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Home My WebLink AboutUnalaska Outside Review Comments 1985 2REQEIYED \SE.O7.ORMEMORANDUMyaspe'State:of Alaska ALACAA POWER AUTHOR]TO:David Denig-Chakroff bate: Unalaska geothermal project manager April 30,1985 Alaska Power Authority FILE NO:' TELEPHONE NO:688-3555 From:Dr.John W.Reeder suspect:Reviewof Republic Geothermal,Geologist Inc.4/2/85 reportEngr.Geol./DGGS 8 First,I appreciate you sending the 4/2/85 draft of the Unalaska Geothermal Project,Phase III Final Report by Republic Geothermal,Inc.,and I appreciate your request for comments on this report.The Alaska PowerAuthorityhasalottobeproudofwithrespecttoitsgeothermalworkat Unalaska Island.We all knew the risk of failure was going to be very high with respect to the geothermal exploratory drilling.But,the Alaska Power Authority continuously kept a firm commitment of following through with this risky exploratory drilling project,which has led to extremely impressive results!I wish you success with your planned Unalaska geothermal feasibility project. With respect to the Republic Geothermal,Inc.draft report,I do have several minor comments that you might consider in your own review comments and/or recommended changes to Republic Geothermal,Inc.First,on their page 3,they state "These investigations resulted in the identification of 23 thermal manifestation areas of which only 12 were previously known".This statement is not true since nearly all of these thermal manifestation areas are located within the original nine fumarole and/or hot-spring fields of the Makushin Volcano region as recognized in 1980 and 1981.I would suggest that they say "These investigations resulted in the description of 23 thermal manifestation areas,some of which were previously unknown". do not like the first two sentences of the last paragraph of page 90.Geological...and-geophysical --evidence does not suggest that thé "Makushinoe--géothermal reservoir is situated primarily within-the Makushin gabbronorite . \Bet Second,I do not like the first sentence of the middle paragraph and I ?c _Stock,or that this reservoir.."is structurally controlled by a major north)."striking fracture zone".Two years ago,they were saying the reservoir was_\Structurally 'controlled by a major northeast striking fracture zone.I hope7of9theirevidenceforthisnorthstrikingfracturezoneisnotjusttheirSOresistivitydataasstatedinthesecondsentenceofthelastparagraphof page 90.The resistivity data is not very strong evidence,although I reallyaliketheresistivitydatasinceitstronglysupportsmanyofmyideasaboutapthisregion.I also have problems with their second sentence on paragraph91.The "inconspicuous east-west striking fracture"and the\7 "northwest-trending fracture"were originally mapped by me in 1980.These-are very pronounced fractures,and the intersection of these fractures infactisthelocationoffumarolefieldno.1.The east-west fracture hasoreaboutaonefootscarponit;i.e.,it should be considered an active fault.\°At first Republic Geothermal,Inc.argued that these faults did not even(uk ,exist.I am now glad that they are finally starting to agree with what I wasY,telling them three years ago.Nevertheless,the word "inconspicuous"is verymakeinappropriatehereandIwouldsuggestthatitbeleftout.}4 02-001 (Rev.10/79) April 30 memorandum to David Denig-Chakroff continued Page 2 My final comment is with respect to the temperature values for the exploratory hole.These values are different from what Republic Geothermal, Inc.originally reported and are different from what they published'at the 1985 Stanford Geothermal Workshop.I would suggest that you ask them to give a complete explanation as part of their Appendix in this final report.Such an explanation should include what data was collected,what instruments were used,what problems occurred in the field,and what was actually done to obtain the final values that were used in this final report.The temperature data is a very important part of their work,so I feel this request for more details is very justified. I only had time to briefly go through the report.Nevertheless,I hope my comments will be of some value to you. .Roari[19S Frese SF-07.0> CRITIQUE ON REPUBLIC GEOTHERMAL'S FINAL REPORT by M.J.Economides The RGI final report is comprehensive and conventional in scope, but at times it deviates into details of minor interest,losing sight of major items.For instance it nowhere explicitly states the steam quality.[I derived it indirectly from Section 5 curves and got confirmation of my calculation from the Denig-Chakroff et al.G.R.C.paper.In fact,this paper is far more informative and gets to the point of whether or not the geothermal resource is worth developing and which technical and economic conditions are important. The Appendices contain a lot of trivial information,including a lengthy treatise on instrument and measurement calibration that should be either routine or included and taken into account by the manufacturer.1!can hardly believe that the A.P.A.paid RGI for a course in instrument calibration. Economics General Impression:It is quite clear that no con- ventional electricity conversion process such as_single flash or dual flash steam cycles can compete with a diesel fired plant in the adverse climatic and logistical environment of the Makushin site.So,with all things considered,geothermal resource development at Unalaska should rely on an advanced conversion cycle and process capable of maximizing the geothermal well output.This should also consider the low steam quality of the resource and the fracture dominated porosity of the reservoir which makes the probability of a second productive well away from ST1 highly uncertain.Hence only those cycles capable of supplying a net power at well head of 10 Mwe from a single well (13 3/8")should be considered.This sort of thinking is not evident in RGI's report. !have many comments on the economic calculations and considerations of RGI and on the rationale which inspired them.It is very,very conservative and inconsistant with exploration findings. Makuschin well capacity (starting p.93):The productive capacity of a 13 3/8"wellbore located at ST1 site and with a minimum 60 PS!IA well head pressure,is estimated at 1,200,000 Ibs/hr total flow.Assuming a 16%steam quality the well would thus yield 192,000 Ibs/hr of superheated steam,which by current standards is roughly equivalent to 8.5 MWe for a dual flash condensing cycle at the worst.How RGI derive the net power figures of Table 16 is a mystery to me.It would definitely deserve at least an explanatory notice inserted in the (too)voluminous appendices. Field Development Costs (starting on p.97):More offensive are the field development costs which are in total contradiction with the abundantly detailed previous exploration work and inconsistent with the logical findings of this project.To me it seems an obvious fact that a reservoir has been hit at about 2000 ft with a full well sustained total flow above 1,200,000 Ibs/hr,of which almost 180,000 Ibs/hr is flashed steam.Then why drill deeper wells (6000 ft)as suggested by costs listed in Tables 14 and 15 as was the case in a previous report by RGI.Also the necessity or lack thereof of injection is not discussed although injection wells are assessed. The report elaborates a great deal on water chemistry.The reservoir is almost fresh water.Why not discharge effluent into a nearby stream.A pertinent environmental impact section should discuss it. My conclusion,from what |know of the water quality of near surface streams,is that there is no need for an injection well and that instead the waste fluid might be turned into an asset by adding a mini hydroelectric turbine (170 kwe). The bottom hole temperature issue,its reversal and the differences between flowing and static temperatures are not even discussed.A potentially critical issue is bypassed. In general the report is not what |would like to see.It does not have a generalized,logical and comprehensive outline of the project.Frankly it does not even come close to a conclusive statement that is remotely of the quality of our recent papers. This narrative should be the centrepiece of the report. As far as the development economics,it is my opinion that they should be removed all together.They are inconsistent with the report's own findings.They are prejudicial and potentially detrimental and contradictory to APA's own reconnaissance study. JE-O7.CR CRITIQUE ON PROFESSOR E.WESCOTT'S SUGGESTION Dr.Wescott is right in stating that resistivity techniques would likely provide the best geophysical method for delineating the reservoir around Makushin.Data acquisition should concentrate in the region west of,and including,Sugarload Plateau.Therefore,I question the validity of running a dipole-dipole profile the length of Makushin Valley. Although this profile may provide useful background data,I believe field work should first be centered around the voleano,and as time permits other profiles could be completed. The rugged terrain around Makushin could be studied by the pole-pole method,as Dr.Wescott states.Also,his idea to incorporate the writing of computer programs,field work,and geophysical interpretation in a thesis project for a graduate student should be given further consideration since a modest monetary expenditure could yield good results. In summary,the geophysical methods proposed by Dr.Wescott are valid and could -yield some very significant results.My question is why didn't Republic Geothermal undertake these studies during their previous two summers on Unalaska.The proposed resistivity project could have been completed for less money by utilizing the personnel and equipment which were already on Unalaska in 1982 and 1983. SE.O7-OR MEMOR.NDUM St e of Alaska TO:David Denig-Chakroff DATE:April 30,1985 RECEIVED Unalaska geothermal project manager , Alaska Power Authority FILE NO:JU!10 1985 TELEPHONE No;688-3555 ALASKA POWER AUTHORITY from:Dr.John W.Reeder susvect.Review of Republic Geothermal, Geologist /,Inc.4/2/85 report.Engr.Geol./DGGS ay First,I appreciate you sending the 4/2/85 draft of the Unalaska Geothermal Project,Phase III Final Report by Republic Geothermal,Inc.,and I appreciate your request for comments on this report.The Alaska PowerAuthorityhasalottobeproudofwithrespecttoitsgeothermalworkatUnalaskaIsland.We all knew the risk of failure was going to be very high with respect to the geothermal exploratory drilling.But,the Alaska Power Authority continuously kept a firm commitment of following through with this risky exploratory drilling project,which has led to extremely impressive results!I wish you success with your planned Unalaska geothermal feasibility project. With respect to the Republic Geothermal,Inc.draft report,I do have several minor comments that you might consider in your own review comments and/or recommended changes to Republic Geothermal,Inc.First,on their page 3,they state "These investigations resulted in the identification of 23 thermal manifestation areas of which only 12 were previously known".This statement is not true since nearly all of these thermal manifestation areas are located within the original nine fumarole and/or hot-spring fields of the Makushin Volcano region as recognized in 1980 and 1981.I would suggest that they say "These investigations resulted in the description of 23 thermal manifestation areas,some of which were previously unknown". Second,I do not like the first sentence of the middle paragraph and I do not like the first two sentences of the last paragraph of page 90. Geological and geophysical evidence does not suggest that the "Makushin geothermal reservoir is situated primarily within the Makushin gabbronorite stock,or that this reservoir "is structurally controlled by a major northstrikingfracturezone".Two years ago,they were saying the reservoir was structurally controlled by a major northeast striking fracture zone.I hope their evidence for this north striking fracture zone is not just their resistivity data as stated in the second sentence of the last paragraph of page 90.The resistivity data is not very strong evidence,although I really like the resistivity data since it strongly supports many of my ideas about this region.I also have problems with their second sentence on paragraph 91.The "inconspicuous east-west striking fracture"and the "northwest-trending fracture"were originally mapped by me in 1980.These are very pronounced fractures,and the intersection of these fractures infactisthelocationoffumarolefieldno.1.The east-west fracture has about a one foot scarp on it;i.e.,it should be consideredan active fault.At first Republic Geothermal,Inc.argued that these faults did not evenexist.I am now glad that they are finally starting to agree with what I was telling them three years ago.Nevertheless,the word "inconspicuous"is very inappropriate here and I would suggest that it be left out. 02-001 (Rev.10/79) April 30 memorandum to David Denig-Chakroff continued Page 2 My final comment is with respect to the temperature values for the exploratory hole.These values are different from what Republic Geothermal, Inc.originally reported and are different from what they published at the 1985 Stanford Geothermal Workshop.I would suggest that you ask them to give a complete explanation as part of their Appendix in this final report.Such an explanation should include what data was collected,what instruments were used,what problems occurred in the field,and what was actually done to obtain the final values that were used in this final report.The temperature data is a very important part of their work,so I feel this request for more details is very justified. I only had time to briefly go through the report.Nevertheless,I hope my comments will be of some value to you. rs areswerPayPe SS -OS O58 MEMOR,DUM otu.e of Alaska To:David Denig-Chakroff DATE:April 30,1985 RECEIVED Unalaska geothermal project manager ; Alaska Power Authority FILE NO:JU!.10 1985 TELEPHONE No:688-3555 ALASKA POWER AUTHORITY From:Dr.John W.Reeder susyect:Review of Republic Geothermal,Geologist A Inc.4/2/85 report.Engr.Geol./DGGS aa First,I appreciate you sending the 4/2/85 draft of the Unalaska Geothermal Project,Phase III Final Report by Republic Geothermal,Inc.,and I appreciate your request for comments on this report.The Alaska:Power Authority has a lot to be proud of with respect to its geothermal work at Unalaska Island.We all knew-the risk of failure was going to be very high with respect to the geothermal exploratory drilling.But,the Alaska Power Authority continuously kept a firm commitment of following through with this risky exploratory drilling project,which has led to extremely impressive results!I wish you success with your planned Unalaska geothermal feasibility project. With respect to the Republic Geothermal,Inc.draft report,I do have several minor comments that you might consider in your own review comments and/or recommended changes to Republic Geothermal,Inc.First,on their page 3,they state "These investigations resulted in the identification of 23 thermal manifestation areas of which only 12 were previously known".This statement is not true since nearly all of these thermal manifestation areas are located within the original nine fumarole and/or hot-spring fields of the Makushin Volcano region as recognized in 1980 and 1981.I would suggest that they say "These investigations resulted in the description of 23 thermal manifestation areas,some of which were previously unknown". Second,I do not like the first sentence of the middle paragraph and I do not like the first two sentences of the last paragraph of page 90. Geological and geophysical evidence does not suggest that the "Makushin geothermal reservoir is situated primarily within the Makushin gabbronorite stock,or that this reservoir "is structurally controlled by a major northstrikingfracturezone".Two years ago,they were saying the reservoir was structurally controlled by a major northeast striking fracture zone.I hope their evidence for this north striking fracture zone is not just their resistivity data as stated in the second sentence of the last paragraph of page 90.The resistivity data is not very strong evidence,although I really like the resistivity data since it strongly supports many of my ideas about this region.I also have problems with their second sentence on paragraph 91.The "inconspicuous east-west striking fracture"and the "northwest-trending fracture"were originally mapped by me in 1980.These are very pronounced fractures,and the intersection of these fractures infactisthelocationoffumarolefieldno.1.The east-west fracture has- about a one foot scarp on it;i.e.,it should be consideredan active fault.At first Republic Geothermal,Inc.argued that these faults did not evenexist.I am now glad that they are finally starting to agree with what I was telling them three years ago.Nevertheless,the word "inconspicuous"is veryinappropriatehereandIwouldsuggestthatitbeleftout. 02-001 (Rev.10/79) April 30 memorandum to David Denig-Chakroff continued Page 2 My final comment is with respect to the temperature values for the exploratory hole.These values are different from what Republic Geothermal, Inc.originally reported and are different from what they published at the 1985 Stanford Geothermal Workshop.I would suggest that you ask them to give a complete explanation as part of their Appendix in this final report.Such an explanation should include what data was collected,what instruments were used,what problems occurred in the field,and what was actually done to obtain the final values that were used in this final report.The temperature data is a very important part of their work,so I feel this request for more details is very justified. I only had time to briefly go through the report.Nevertheless,I hope my comments will be of some value to you. a OS OP UK ahetten serene oer|i |;Yr |1 rd 7 t =fist Pai iss rots US Army Corps Date:october 28,1985 | of Engineers Identification No.: pr_g¢_oeAlaskaDistrictInreplyrefertoaboveIdentification NumberPlanFormulationSection NOTICE OF DECLARATION OF NO FEDERAL INTEREST IN HYDROELECTRIC POWER AT UNALASKA,ALASKA I am announcing a decision by the Board of Engineers for RiversandHarbors(BERH)and by the Assistant Secretary of the Army thatFederaldevelopmentofhydropowerfacilitiesatUnalaska,Alaskawillnotbepursuedatthistime.A 960-kilowatt (kW)plant tosupplementtheexistingdieselgenerationsysteminUnalaskawas studied by my Planning Branch and submitted to the BERH in March 1985. The Board found the Unalaska hydropower plan to be economicallyjustified,technically sound,and environmentally acceptable.However,it also found that non-Federal implementation of the planispracticalandwithinthefinancialcapabilityoflocalinterests,and that all benefits would be realized throughnon-Federal development.Under these conditions,the.Administration's policy is to decline Federal development and encourage non-Federal interests to develop their own hydropowerpotentialunderFederalEnergyRegulatoryCommissionprocedures.Federal authorization for the project is no longer being pursued. Hydropower at Unalaska was studied pursuant to a resolution of theU.S.Senate Committee on Public Works dated October 1,1976,directing the Corps of Engineers to determine the feasibility ofinstallingsmallhydroelectricplantsinisolatedAlaskan communities. Unalaska is located on Unalaska Island in the eastern Aleutian chain,about 800 miles southwest of Anchorage.The community'seconomicbaseiscommercialfishingandseafoodprocessing,withnewoil-related industry growing in importance.Unalaska scores well as a potential hydropower location because it has a mild climate,it is a stable community with a growing population,andithastwogoodhydropowersitesfromatechnicalstandpoint. The proposed Unalaska hydropower system,presented in a Feasibility Report dated June 1984,has two parts:a run-of-river facility on the Shaishnikof River and a pressure reducing turbine in the existing water supply penstock on Pyramid Creek.The Shaishnikof project would have two small generators totaling 700 kW in capacity;the Pyramid Creek turbine would add 260 kW. In addition,a fishery enhancement measure was proposed for the Shaishnikof River. The estimated first cost of the Shaishnikof River portion was $5.6 million,based on October 1983 price levels.The estimated first cost of the Pyramid Creek portion was $816,000.The combined projects would produce an estimated 5,288,000 kilowatt-hours of energy annually. The Feasibility Report describing the Unalaska hydropower plans was furnished to State,Federal,and local agencies.The BERH recommended that it be sent forward to the Acting Assistant Secretary of the Army (Civil Works),who returned the report to the Alaska District.A limited number of copies of the report, including the Environmental Impact Statement,may be purchased for $4.50 each. Further information on this study may be obtained from my office or from Mr.Carl Borash,Chief of my Plan Formulation Section, P.0.Box 898,Anchorage,Alaska 99506-0898.The telephone number is (907)753-2620. Wilbur T.Gregoryy ur. Colonel,Corps of Engineers District Engineer TRAIL LAKE a} BERING SEA Py 7)Mere,ow 'Gi Guilt of AleckeA. GRE FIGURE BELOW ZzBERING SEA Nikoiek! PACIFIC OCEAN Unalaska,Alaska SMALL HYDROPOWER INTERIM FEASIBILITY STUDY LOCATION &VICINITY MAP Alaska District,Corpe of Engineers FIGURE | SCALE IN KILOMETERS EaSHAISHNIKOF RIVER DAMSITE TRAIL LAKE QUARRY *SITE PYRAMID CREEK ]ANYON AREAPINKSALMON"5 (FISHERIES ENHANCEMENTBLOCKCONSTRUCTIONAREA) Wa eS UNALASKA,ALASKA SMALL HYDROPOWERis@WERHOUSEFEASIBILITYSTUDY Alaska District,Corps of Engineers PLATE CITY OF UNALASKA P.O,BOX 89 UNALASKA,ALASKA 99685 (907)581-1251 "Capital,of the q{feutianss UNALASKA,ALASKA John Parisena Arthur Young and Company 1031 West 4th Avenue Suite 600 Anchorage,Alaska 99501 Dear Mr.Parisena: We wish to thank you for your recent draft of the "Electrical Rate and Load Projection"study dated November,1984.We apprec- iate the time and effort that you and your staff have invested in this study. The November copy of the draft was a considerable improvement over your previous effort.Upon review,we find that some areas need to be addressed more specifically.To do this we need to re-evaluate,in my opinion,the original purpose or need for this study. The Alaska Power Authority provided a grant for an electrical rate and load projection study for possible use with the legislature in determining the feasibility of installing a geothermal generation plant on Unalaska Island. The Unalaska Electric Utility Department had hoped to be able to use the study for the following: a.Bettering customer relations involving projected rates. b.Clarification of projects or needs when addressing the city council. c.To help identify and forecast various types of loads. d.Provide cogeneration avoided costs. e.Assist the Utility in providing data pertinent to future funding. f.Justify the installation of our heat recovery system that is funded with a grant from Alaska Power Authority. One of the concerns with the draft is that most of our stated considerations were not addressed to the community's benefit. Some of the changes that we envision necessary to make the draft useable,within the limits stated,would be: Consider the cost of all added equipment at current in- dustry prices,i.e.,reference "generation at bargain prices."Our reasoning is that the generation grant from the State of Alaska (not A.P.A.)is inadequate to cover all expenses for added new generation.We,there- fore,must use this study as a tool to justify and ob- tain funds. Your alternative regarding large interruptable power users appears to utilize cogeneration from various sources presently installed and privately owned.In our opinion,formed from discussion with these users,and by the cogeneration ordinance,the costs associated with parallel operation would prohibit customer interest. Suggest you provide a "glossary of terms"to assist the unfamiliar reader with definitions for terms such as: a.Tilted b.Load Factors c.True-ups d.Ratchet Cost of fuel used for preparation of tables on our cur- rent system should reflect a $1.00 per gallon average. We believe the source of confusion here rests with the fact that fuel cost will be approximately $.88 in our new facility. Our primary area of concern is the need for a straight- forward,understandable narrative which explains the present rate structure,as compared to the proposed sys- tem,and the true associated costs for both.It appears as though you presented information in the same format as you would have for a much larger utility;this is not what we had in mind. We desired tables in a readable style,possibly in text, that would help us make an informed decision involving complex issues.An example would be Task Two,Page one. One possible solution (or aid)may be two sets of tables,one for our current system,and another for your proposed method of operation. We find that the operating costs projected into Table #6 do not include: a.Fringe benefits,costs,or overtime consideration. b.Interest expense. c.Lease purchase cost associated with l-Cat.3512 and leased powerhouse. 7.Table #5A shows 1500 Kw (total system)installed. This figure should also include one leased powerhouse: Unit 5 130 Kw Unit 6 100 Kw Unit 7 100 Kw Unit 8 300 Kw bringing the system total generation to 2130 Kw,plus the installations at our new powerhouse projected for 1985 and 1986. 8.Table 5A also shows the system average demand to be 300 Kw for test year 1983 or table year 1984.This projec- tion would be more accurate if we include both power- houses at 500 Kw total. Again,we appreciate your work.We do feel that there have been too many people involved with this draft.This,partly due to the changes in personnel within the City of Unalaska,and the report problems partly due to communication between the parties. We believe that proper,complete information was provided and now we simply must understand each other's needs and project the necessary relative information to paper.To do this we suggest, possibly,that you send a person to Unalaska with a Compag com- puter and software;this would allow us the opportunity to assist in the preparation of information and the printing of the projec- ted data. May we get together and see if there is some timely solution to providing this needed material so that we may all look profess- ional to these third parties involved? If you have any input or questions,please contact: Carl McCommell,Utility Manager or Jeff Currier,Public Works Director,at 481-1260. Sincerely, Cant NeComvdO=ar Carl McConnell Utility Manager CM :rg:mh cce:Nancy Gross,City Manager Department of Public Works Dave Denig Shakroff,A.P.A. MEMORANDUM TO: FROM: 02-001A(Rev.10/79) S¥.O7.02 State of Alaska David Denig-Chakroff DATE:|January 8,1985 Project Manager Mike Hubbard -7#ihe. FILE NO: TELEPHONE NO: SUBJECT:Review of Draft Financial Analyst Electrical Rate and Load Projection Study -City of Unalaska Pursuant to your request,I have reviewed the draft Electrical Rate andLoadProjectionStudy(November 1984)performed by Arthur Young and Company for the City of Unalaska.The report is divided into sections per task number,and my comments below are set forth accordingly. Because of my unfamiliarity with the City,its customers,and its load characteristics,some of my comments may not be significant or can readily be explained. Task 1 -Estimate Future Peak and Energy Requirements 1.The customer growth rates shown on Table 3 for the 1989-1993timeperiod(4 years)is the same as that shown for the two ensuing five-year periods (1993-1998 and 1998-2003).Although not critical to the overall analysis,the rate should be 8.24 percent.This error is found on most of the tables. The compounded annual increase in energy use per customer shown on Table 4 from 1984 to 1989 for each class is:GS-1 - 3.1 percent;GS-2 -13.5 percent;Large power -3.6 percent; and Street lights -7.0 percent.Both GS-2 and Street lights are significantly higher than the rest,although street light increases may be explained by an expansion of the system. There does not appear to be any backup to the load factors input on Table 5B,and they increase significantly through 1989.Even the text of the report points out their signif- icance on page I-4.Because of the level of increase in load factor in relation to the energy use per customer,the peakdemandineachcustomerclasslexceptGS-2)decreases.This implies that the customers are using increasing amounts ofenergy(from Table 4)and energy consumption is shifting to off-peak periods. Task 2 -System Expansion to Currently Unserved Consumers 1. 7758/314 The projected annual energy requirements shown for the poten- tial customers appear to be a function of demand and load factor assumptions.I presume that many of these provide their own generation,and historical energy requirements may be available.Additionally,there is no discussion on load growth for any of these customers. Memo to Davi)2nig-Chakroff January 9,lsou Page 2 The task does not appear to be complete as there is little discussion on the costs involved to provide service to these customers or the rate at which these customers would purchase such power.This rate would probably be at or below their avoided cost. Task 3 -Cogeneration Potential 1. 7758/314 The report refers to those potential customers listed in Task 2,however,the existing resources,installed capacities,anduse(heat or power)are not shown.These should be listed to get a better feel for the potential. The discussion on page III-5 on the avoided energy cost refers to significant changes in the future.Will heat rates change that significantly? The application of avoided capacity costs discussed on page III-5,can be related to intermediate requirements and not just baseload and peaking. Page III-6 and III-7 refer to generating resources available to the City at "bargain"prices.What is the definition of "bargin";and does it refer to installed,operating or life-cycle costs? The discussion on page III-8 refers to a potential hydro- electric purchase,but the report does not recommend such action because of the availability of grant money or low-cost loans.The alternative to the hydro project is,I assume,a diesel-fired generator which is characterized by relatively low installed costs and high operating costs.Did the report take this into account,or is the recommendation purely subjective? Page III-9 discussed capacity credit,and this discussion should pertain to not only hydro,but all cogeneration. Technically,cogeneration is the generation of two products(i.e.,heat and power)from the same resource,and hydro and wind do not fall into this category.They do,however,use renewable resources and are treated favorably by FERC and the APUC. I am not sure what the second-to-last paragraph on page III-9 means. Memo to Davi =anig-ChakroffJanuary8,lsvs Page 3 8.The task does not appear to be complete as several questions are left unanswered.These include: What is the City's avoided capacity cost? -What are the effects of the City's cogeneration policy on the economics of cogenerated power? -What is the existing electrical generation (both City andothers)? Task 4 -Waste Heat Recovery Potential 1.The report does not take into account existing heat recovery systems in the City,because the existing loads will be taken off the system.Why is this being done?Were there problems, and,if so,what were they? 2.The report does not recommend the Airport site because of economics.A quick calculation shows that the present valueofthe$8,400 annual savings escalated at $500 per year is approximately $287,000 over a 15 year period using a discount factor of 10 percent.This is double the installed cost of$132,000. 3.Where are the numbers that substantiate the claim that the economics are not in favor of providing waste heat to distant points?What is the breakeven distance? 4.The first paragraph under "Long Term"on page IV-2 needsfurtherexplanation. 5.The study refers to the current heat recovery system and briefly touched on its problems,including noise and matching heating requirements with power requirements.What are the economics of operating the generator for additional heat when needed in lieu of connecting to a direct-fired system? Task 5 -Capacity Addition/Retirement Plan and Rate Requirements 1.What year is the annual interest expense on page V-3 calcu- lated for?Will it change significantly in the next few years? 2.Future expenses are estimated by past inflation "trends." What length of time was used to find those trends,and are the influencing factors found during that period still in exis- tence? 3.To ensure that the rates set via a rate study will collect revenues,a good estimate of the next couple years'expenses must be developed.This requires more effort than "trending" past inflation. 7758/314 Memo to Davic :nig-Chakroff January 8,lou. Page 4 10. Is the bad debt expense ratio (page V-5)increased each year or held at a constant ratio? Is 3 percent fuel escalation a reasonable rate?This is less than or equal to all of the other assumed inflation rates except purchased power and leased equipment. Why is the fuel efficiency increased from 10 Kwh/gal to 12 Kwh/gal?Is this consistent with the avoided energy cost analysis is Task 3? Page V-7 refers to two versions of Table 10.Where is the second? The expenses included in the revenue requirements does not appear to include interest expense.This could result in adeficitofnearly$50,000 per year. The study states that principal reduction on loans is to be funded through depreciation.Given the interest expense on page V-3,the principal requirements are approximately$106,540,an amount less than the $70,662 depreciation ex-pense.If the $36,210 return on rate base is included,there is enough for principal reduction but no interest expense or capital additions funded through revenues. I am not convinced that the capacity charge for large power on Table 10 is calculated correctly.After the fixed charges are allocated based on coincident peak,the rate should be deter- mined using the billing demand.The billing demand in eachmonthisequaltothegreaterof1)the actual monthly non-coincident peak demand or 2)the ratchet applied to the non-coincident peak during the previous 12 months.On an annual basis (assuming that the peak during the remaining 11 months is less than the annual peak),the rate should be determined by the following ratio: Allocated Fixed Costs (NCP+(11)(.75)(NCP)) or Allocated Fixed Costs 9.25 NCP Where NCP =Non-Coincident Peak If the monthly demands in the off-peak months are greater than the ratcheted demand,then the denominator of the above ratio would increase and the rate decrease. 7758/314 'Memo to Davic nig-Chakroff January 9,1¢L. Page 5 11.The language on capacity additions on page V-12 refers to a "worse case scenario."What is the definition of "worse case"?If it refers to additional loads being added to the system,it may help spread the utility's fixed costs over more generation. General The report,in my opinion,falls short of fully addressing the tasks identified.There is very little analysis,and the report is filled with generalities.Additionally,there are numerous typos and areas of unclear language. I would be happy to discuss the above with you to clarify any of my thoughts. MH/ald 7758/314 BB.07.0Aa ST Ava ib L A S A bE |BILL SHEFFIELD,GOVERNOR DEPARTMENT OF NATURAL RESOURCES O POUCH 7-028DIVISIONOFGEOLOGICAL&GEOPHYSICAL SURVEYS PHONE,RE ALASKA 99510 794 UNIVERSITYFAIRBANKS,ALASKA govon ee May 1,1984 (907)474-7147 .RE Dave Denig-Chakroff CEIVED Alaska Power Authority . 334 W.5th Ave.,2nd floor MA'08 1983 Anchorage,Alaska 99501 ALASKA PowER AUTHORITY Dear Dave: Please find enclosed our review of the draft version of thd phase II final report on the Unalaska Geothermal Exploration Project prepared by Republic Geothermal,Inc.(RGI)of Santa Fe Springs,California.Both of the undersigned have reviewed the report with Nye concentrating on geologic aspects and Motyka on thermal fluids and well-test.Larry Queen,a graduate student studying mineral alteration in the Makushin cores,has also contributed to the review. As you can see we found several areas that we felt deserved commentary.Our criticisms and suggestions are offered in the spirit of scientific inquiry and exchange and we hope that RGI will receive them in the same manner.In order to expedite matters we have taken the liberty of sending our review directly to RGI.We hope our comments and subsequent discussions of differences in interpretation will serve to further increase our mutual understanding of the Makushin geothermal system. We have included a number of data tables giving our preliminary analyses of well fluids and a preliminary copy of a well-log report prepared by Larry Queen.We hope these data will be of benefit to the Unalaska geothermal program. On page XII -41 of the RGI report there is reference to a "Geothermal Electrical Power Generating Analysis,Unalaska Island,"Republic Geothermal, Inc.Report to the Alaska Power Authority,March 1984.We have not as yet received this report and would like a copy of if available. We look forward to working on the Makushin project once again this summer and plan to be on hand for the terminal stages of the 45-day flow test and for deepening ST-1R.However,lack of funding may curtail our operations.We shall keep you appraised of our plans as our funding situation clarifies. Sincerely, Kormon Moyha Con) Roman J.Motyka Dr.Christopher Nye Manager,DGGS Geothermal Program Geologist DGGS Review of "Phase II final report: The Unalaska Geothermal Exploration Project",draft, by Republic Geothermal,Inc. General Comments -Motyka 1)The report is almost completely devoid of documenting references.Is there a presumption that by this stage in the project contributing investigators are known to one another and references are unnecessary or were references omitted as a matter of expediency?Either way,anyone outside of the working group reading this RGI report would have difficulty finding the necessary background information for the project and for the Makushin geothermal area in general. References would also help people within the working group track the source of ideas about which there is not universal agreement.Numerous articles and reports by RGI,DGGS,and other investigators have been published and could and should have been referenced to document the report.Additionally the laboratories performing the analyses of stable isotopes and water chemistry of well-fluids are not cited. 2)In view of the poor documentation elsewhere in the report it is puzzling that the comments of Dr.Doug Sheppard should appear in the text (pg.XII-32 to 33).Doug's comments were informally addressed to us (DGGS)and accompanied gas analyses that Doug had performed on the test-well samples. Copies of Doug's letter and preliminary results were sent to RGI as a courtesy because of the problems RGI had in their own sampling program.It seems inappropriate to us that informal comments received second hand by RGI should be quoted without at least further discussion with Doug. Please also note that the USGS'participation in the sampling program is through a cooperative program with DGGS.The sampling and analysis of the well-fluids are a joint DGGS-USGS effort.Also,Doug's analyses were preliminary and should have been referenced as such. 3)With regard to the last point,we have found a discrepancy in Doug's H,S analyses.Re-analysis by Cathy Janik (USGS)and examination of gas data by Motyka indicate Doug's H,S values are an order of magnitude too low.Doug has since returned to DSIR in New Zealand.We are in communication with him and are trying to determine the source of the discrepancy.We feel the revised analyses given in Table 6 (attached)are valid and apologize for the inconvenience the change in H,S analysis may cause you.The change should not affect your report's conclusions other than gas geothermometer results (see our Table 9). 4)DGGS and RGI employed different sampling techniques for collecting test-well waters and gases.We used a New Zealand type mini-cyclone separator;the RGI method is described in the report.The results of the analyses offer a good opportunity to check consistency between the methods. Except for silica and fluoride,the reservoir water chemistries of samples collected by the two different methods compare quite well (compare our Table 3 to RGI table 15).The differences in Si0,and F may be due to lab techniquesratherthesamplingmethod. Comparing stable isotope values we are in agreement on 189/165 but differ slightly on D/H (compare our Table 5 to pg.XII-27).Again the difference may be due to lab techniques.Regarding gas analyses,RGI's CO,analyses and estimates of concentration of co,in total fluids appear similar to thosedeterminedbyDGGS-USGS. 5)There is no discussion of the potential importance the presence of anhydrite in the 1949'fracture zone has on understanding the geothermal system.Using a chip from the 1949'fracture supplied to us by RGI our ow XRD analyses showed the outermost mineral on the fracture to be anhydrite. The anhydrite was deposited on a layer of quartz+calcite which in turn covers chloritized gabbronorite.Anhydrite was also identified in a vein at 1944' and in veins at about 600°. Anhydrite deposition in the 1949'fracture system may indicate that the well is in an area of recharge,on the edge of the geothermal system,or has penetrated a zone where aerated surface waters mix with reservoir waters. Anhydrite implications are discussed further under "Note on caso)". 6)Although our chemical analyses show a much lower concentration of dissolved silica in the well waters than the RGI results (292 ppm vs.388 ppm),our quartz geothermometer still indicates resgrvoir temperatures of about 208°C.Our other geothermometers,including del 0,H,0-SO »give reservoirtemperaturesrangingfrom210°to 240°C (see our tafle 9).If anhydrite is being actively deposited,then the SO,concentration is also out ofequilibriumwiththemeasuredBHToft93°c (see discussion in "Note on CASO,").As noted by RGI,the apparent disequilibrium between the variousgeotfermometersandthemeasuredBHTremainspuzzling. 7)There is no discussion of the apparent recent and rapid depletion of water from the reservoir as manifested by the depth of the water table,Bamford's trace element geochemistry,alteration mineralogy,and occurrence of halite deposits.Possibility -some of the recharge zone may have been cut-off by recent debris flows and lava flows. 8)Some key anomalies and differences which need to be resolved during this summer's field season are:1)the apparent disequilibrium between BHT and reservoir fluid chemistry,2)discrepancies in downhole temperature and pressure measurements,3)the cause of the recent change in the upper part of the geothermal system from liquid to vapor dominated,4)discrepancies between DGGS and RGI SiO,and F analyses,and 5)geometry of the reservoir (possiblythroughresistivitystudies). Specific Comments -Motyka Pg.X-9 and Table 1:Why wasn't the temperature logging of hole E-1 extended beyond 925'depth? Pg.X-21 and 22:(Compare RGI table 3 -to DGGS Table 6,gas chemistry for 672'fracture.Our analysis shows a much lower gas/steam ratio (Xg about0.113).The probable reason that no H,S odor was detected is because thenon-condensible fraction was so low and H,S is a small fraction of the non-condensibles.For comparison a sample obtained from fumarole #1 in 1983 was analyzed and gave a Xg of about 0.180 and about 2.2 mole %HASofnon-condensibles. Pe. Pg. Pg. Pg. Pg. Pg. Peg. Pg. Pg. Pg. XI-1,Table 10:HCO,is probably much less than 55 ppm (see notes onHCO,). XI-5:Our gas chemistry showed the non-condensible gas fraction for the 672'fracture to be quite low (see DGGS Table 6).Gas chemistries for the 672'and 1949'fracture zones are roughly similar,although the 1949' zone has a lower gas/steam ratio.Gas/steam ratio for fluids flashed to atmospheric pressure for the 1949"zone would probably be less than 0.05 compared to about 0.1 for the 672'fracture.Note the similarity in initial wellhead pressure buildup for the two fracture systems (about 108 psig). XII-18 B.1.:Isn't it possible that the fracture zones at 670'and 1949! are connected to one another via the same hot-water reservoir?With the water table estimated to be at a depth of 900",steam and gases could be boiling off the hot-water system and feeding the 672"fracture.What effect would such internal communication between the two fracture systems have on the well test? XII-24,Table 13:Lab and analyst not cited.HCO,is probably less than10ppm. XII-25,Table 14:Need references for geothermometers.Fournier,1981, has a general review.What is the reference for improved Si0,and Na/Li thermometers?We are in disagreement with regard to silica témperatures (see DGGS Table 9). Which "reliable"geothermometers were used? XII-28,Table 15:A HCO,value of 12 ppm does not follow from Table 14(see discussion on XII-29).Our average chemistry for reservoir fluid (DGGS Table 3)compares well with RGI Table 15 except for Si0,and F.These discrepancies need to be sorted out.Our lab normally fakes special care in Sid,analyses because of their importance forgeothermometry. XII-27,Table 16:Compare with DGGS Tablegs.Also,please cite lab doingRGIisotopeanalyses.Note:The small "0 shift between the reservoir waters and meteoric water line (about 1 per mil)suggests one or a combination of the following:a large water-rock ratio;fast flow-through and little interaction;or low exchange due to low temperatures sess than 200°C).Samples of the gabbro core are beinganalyzedfor0todeterminedegreeofexchangeandwater-rock ratio. XII-28,Figure 11:Where did the data come from?References? XII-29,top paragraph:I do not see how these two conclusions follow from RGI isotope chemistry. XII-29,section 4:Note on carbonate chemistry:DGGS sample 77 (see DGGS Table 2)was titrated,back-titrated and re-titrated in the field to eliminate the interferences of boron,silica and ammonia.The titrations showed the reservoir waters had essentially no HCO,.Similar titrationsofsamples74,75,and 76 back at the DGGS lab contirmed this conclusion. -3- Additional evidence for lack of HCO,in the reservoir waters comes from C.Janik of the U.S.Geological Survey.Two liters of water were needed to obtain any noticeable precipitate when ammoniacal Sygl,was added tothewaters.The precipitate is used to determine del C-HCO,by evolving CO,from SrC0,.The CO,yield was extremely low (leSs than 22%)indicating that little of the precipitate was Src0,. In the second paragraph of section 4,do you mean anhydrite rather than gypsum?Also,we have identified calcite in the fracture zone but it has been covered by a layer of anhydrite.The question is whether anhydrite is being actively deposited (see note later on). Pg.XII-32:Doug Sheppard (actually of DSIR in New Zealand)should not be quoted without talking to him directly. Pg.XII-33,Table 18:The gas data have been re-examined and the corrected values are given in DGGS Table 6.(Note that the "less than"symbols under the He heading should be reversed). Pg.XII-34,section 5:A re-sampling and re-analysis of gases from fumarole #1 in 1983 gave the following results:Xg about 0.18;CO,=79.32;HS =2.20;H,=0.24;Ar =0.21;0,=0.12;and N,=17.24,alf in mole %.°IEacorrectionismadeforthehighNo(probably the result of aircontaminationwith0,having been rémoved in oxidation reactions)thenthe672'fracture and fumarole #1 do appear similar.Our gas chemistry gives a geothermometer temperature for 670'(DGGS sample #49)of about 233°C.(Note:Please cite or reference the type of gas geothermometer you are using). Also,see discussion on the possibility that fracture 672'(and fumarole #12)are fed from the 1949'hot-water reservoir. Pg.XII-35,numbers 7 and 8:We differ in our silica determinations and geothermometry.Ours predict a reservoir temperature of about 208°C (see DGGS table 9). Pg.XII-36:Needs numerous documenting references. Pg.XII-37:Needs numerous documenting references. Pg.XII-37,bottom paragraph:I agree that the enthalpy transfer from the "intrusion"to the geothermal reservoir is probably predominantly conductive.However,I disagree with the implications you have drawn from DGGS'summit fumarole data.First of all,the sampled fumarole was at boiling point and was probably highly contaminated with near-surface snow yelt,which would mask any "magmatic"steam component.Second,thehighHe{,He ratio of 7.8 clearly indicates a magmatic influence.Third,the del C-CO,for the summit fumarole (#6 in Table 11)is -10.0,which is heavier than the CO,in most of the flank fumaroles and close to the range estimated for "magmatic"co,of -4 to 9. Pg.XII-39,top paragraph:Although an offset asymmetric heat source may be RGI's working hypothesis I believe the evidence cited by RGI to support this hypothesis is incorrect. Point 1:1)The west side of Makushin volcano retains the shape of a shield volcano,indicating that a substantial number of more recent flows have been shed to the west;2)the thick sequence of lava flows that fill Driftwood Valley appear to have had their source high up on the east flank of Makushin volcano and not east of the volcano;3)post-glacial volcanic vents occur south (Pakushin)and west (Kadin Craters),as well as east (Sugarloaf)of Makushin volcano. Point 2:As I noted last year when this same "argument™was presented, the temperature profiles of D-1l and E-1 are not directly comparable because of the difference in stratigraphy at the two holes.900-1200'of volcanic flows overlie the gabbro at D-l.Cold ground waters infiltrating the porous flows produce a nearly isothermal low-temperature region down to 1,000".Such masking of deeper conditions by volcanic flows is seen at other volcanic-type geothermal systems,such as in the Cascades.It would be more appropriate to compare isotherms at similar depths into the gabbro in which case D-1 and E-1 are similar. References to literature discussing offset heat sources at Cerro Prieto, etc.would be appreciated. The regional resistivity study suggested by DGGS should help answer questions on the geometry of the geothermal system. Pg.XII-40,last paragraph:Halite deposits and glacier valley waters are discussed in Motyka and others,1983. Note on CaSO, The following discussion was drawn from Blount and Dickson (1969,Geochim. Cosmochim.Acta,v.33 p.227-245),Marshall and others (1964,J.Chem.Eng. Data,v.9 p.187-191),and Giggenbach (1980,Geochim.Cosmochim.Acta,v.44 p.2021-2032). Anhydrite was found at both the 1949'fracture and in veins above the fracture.Precipitation of anhydrite can indicate that waters are migrating up-temperature (i.e.,in the recharge zone).Although CaSO,solubility is dependent on both T and P,the temperature dependence is much greater than pressure effect.Thus as waters become hotter,CaSO,becomes increasingly less soluble and therefore precipitates.In contrast,for waters migrating down temperature gradient (i.e.,upflow from warmer to cooler temperature regions),CaSO,becomes increasingly soluble and is unlikely to precipitate. An alternate possibility is that the rising column of thermal fluids is coming into contact with aerated,non-thermal ground water producing oxidizing conditions and decreasing CaSO,solubility. Both of these possibilities suggest that ST-1 is at the margin of the system. One further possibility is that a nearly saturated solution rises at a constant temperature (isothermal)along a pressure gradient.Decreasing pressure would decrease solubility leading to precipitation.This is the least likely possibility because of the small pressure dependence of CaSO solubility. The calculated concentration of CaSO,in the Makushin reservoir fluids isabout0.00077 moles CaSO,/kg H,0. 4 The solubility of CaSO,in pure water as a function of T and P,from BlountandDickson,1969 is: log,m =-2.917 -0.02314T +0.001179P +6.02 x 10 °pr*- 2.07 x 107'p* The calculated equilibrium saturated temperature for pressure at the bottom of ST-1 is: T =185°C The effect of salinity must now be considered because CaSO,becomes increasingly more soluble with increasing concentration of 'NaCl.The molar concentration of salts for the Makushin reservoir is about 0.09. Extrapolating data from Blount and Dickson (1969),and Marshall and others (1964)indicates the equilibrium saturation temperature for the CaSO concentration present in the Makushin test-well waters must be greater than 200°C and probably about 210 to 220°C.(Effects of P are negligible at the pressures of the system.) Thus,once again we are faced with disparity between mineral-water equilibria and the measured BHT at ST-l. Regardless of whether CaSO,is presently being precipitated,the occurrence of anhydrite indicates it must have been deposited in the recent past. Comments -Nye XII-16,paragraph 2:How do you reconcile a single geochemical signature with two distinct alteration assemblages (above and below 676',XII-8)? XII-37,paragraph 3:Sugarloaf is older than,and unrelated to,the andesite flows that surround it,underlie D-l,and fill Driftwood Valley.These flows have been overrun by a post-Pleistocene glaciation.Thus,while Sugarloaf is post-Pleistocene,it is not post-glacial,and its age is somewhere between 10,000 and 3,000 yrs.Note also that Sugarloaf is a relatively small flank vent,especially compared to the Driftwood Valley flows.The source vent for the Driftwood Valley flows must be west of (uphill from)D-1. XII-39,paragraph 1:I agree with Motyka's comments on this paragraph and note,additionally,that the Driftwood Valley flows are the largest volume post-Pleistocene volcanic event.Also,the mixed nature of these flows strongly suggests that an old,evolved magma chamber did (or does) exist under the summit region of Makushin.Thus,based on the evidence from volcanic chemical stratigraphy,I do not believe that the heat source is asymetric to the volcano. XII-39,paragraph 2:As a rule,Makushin volcanics overlying the gabbro are not altered.The "altered basalt members"are more likely to be altered pyroclastics.Thus the evidence around the drill holes suggests that the self-sealed portion of the gabbro may be the most efffective cap to the system.The ashy matrix of the Unalaska Formation must also be fairly impermeable to fluids,since it does not support fractures very well. XII-40,paragraph 1:We have looked in vain for NE-trending structures. There is certainly no field evidence we could find for an "older,highly tectonized fracture",The "contemporary seismicity"is down Makushin Valley,well east of the proposed fracture zone.We have seen no evidence of recent movement on any fractures,except in the case of landsliding and slumping,but there are no major slumps in the vicinity of active geothermal manifestations. The only clear evidence that I am aware of suggesting a NE-trending structure is the alignment of the Glacier Valley and Makushin Valley hot springs and fumaroles.Even this evidence is not completely compelling since a line enclosing all surface geothermal manifestations is roughly circular. Because of the lack of independent evidence for a NE-trending fracture I think it is important to entertain additional possibilities for the apparent alignment of fumaroles and hot springs.Such possibilities include.1)A greater depth of erosion in the Glacier and Makushin Valley region,which comes closer to penetrating the self-sealed gabbro cap.2)More complete unroofing of the gabbro in the west than in the east,which more effectively penetrates the (probably)impermeable Unalaska Formation.And 3)a heat source which is symmetrical beneath the Makushin summit.In this case the westernmost part of the reservoir gabbro would be the hottest.West of ST-l the thick cover of highly permeable volcanics would prohibit the hot water or steam from reaching the surface.Geothermal fluids would instead vent along the path of least resistance,which should be through the gabbro to low elevations. XII-40,paragraph 2:Once again,I doubt that fractures are important in determining resource position.In spite of a concerted effort to find faults we found few with significant offset,and none with significant breccia zones.I expect the pervasive jointing to be most important in determining permeability. Combined Comments -Queen 1.Thin sections of the pluton indicate plagioclase compositions of An ' clinopyroxenes and orthopyroxenes making up between 10-30%of the mode, and an absence of alkali feldspars.The absence of alkali feldspar was confirmed by staining a representative suite of samples.This puts the composition of the pluton in the gabbro field of the IUGS classification. We don't want to quibble over details of classification but note that if the geothermal system is hosted by the pluton then the type of alteration products are directly influenced by the pluton's composition. 2.(XII-2)My examination of the core indicates that there are very few if any younger plutonic dikes (i.e.,no gabbro or diorite dikes in the -7- 3. pluton).Some features which appear to be dikes may actually be a) deuteric alteration of the gabbro to albite+quartztepidote+biotite,b) hornfelsed sheets of Unalaska Formation,these may be quite dark and well crystallized,or c)intrusive breccia which has been deuterically altered so that it contains biotite and hornblende rather than pyroxenes.There are also dikes of hypabyssal andesite. (XII-2)I do not believe that the differences in fracturing,veining,and alteration can all be related to the present geothermal regime.There are at least five alteration assemblages which I can determine from the core (see my discussion of alteration assemblages in the text of the enclosed core log).Only two of these appear to be related to the present stage of the geothermal system.The two most common alteration assemblages are,as I now interpret them,deuteric and have nothing to do with the present system.The other assemblage which is found in ST-1 and D-1 consists of anhydritet+tcalcitetmagnetite+pyrite+chloritetepidote. This is the assemblage which occurs above the 672 ft fracture zone in D-l and at the bottom of D-1.This assemblage was deposited by hot waters under fairly low fo.-This cannot be taken to represent a part of thecurrentsystem. (XII-2)Magnetite is an abundant and important alteration mineral above 672 ft in ST-l. (XII-2)My x-ray studies indicate montmorillonite rather than kaolinite is the dominant clay mineral seen in all the cores. (XII-15)Tectonic activity is not the only,or even most likely,way to reopen existing veins.Veins are zones of weakness in a rock and thus can be reopened any phenomina which alters the existing stress regime in a rock.Changes in temperature and loss of confining pressure due to erosion of overburden or retreat of glaciers may be the actual cause of refracturing. (XTI-18)The sample which is stated to have come from the 672'steam entry zone actually came from 644"(see Appendix J).The core log on page XII-3 and my log both show an aplitic dike at 644'.The aplitic dikes seen throughout the pluton are for the most part late stage pegmatites. Thus while the assemblage seen from this sample is indicative of high temperature alteration it predates the current hydrothermal system. (XII-27)Gypsum is not found in the core. (XII-39)The recent lava flows in the core are not altered.It seems unlikely that they would form the cap.There is a basal lahar which is scattered and limited in extent which may act as a cap.It may be that the pluton does not extend much further westward. Table 1.Fraction of Steam Separated from Flashed Well Fluids! Sample #9 Collection Collection Steam DGGS USGS Date Time Pressure,Bars Temperature,°C Fraction 71 1 8-27-83 (+1.5 hr)2.00 120 0.144 74 2A 9-1-83 17:30 3.17 135.5 0.116 75 3B 9-2-83 10:10 3.03 134 0.119 76 4B 9-2-83 16:20 4.48 147.5 0.093 77 5A 9-3-83 19:50 4.55 147.5 0.092 1.Fluids collected using New Zealand type mini-cyclone separator. 2.Parenthetical value for 71 is the time elapsed after initial discharge from fracture zone at 1946'depth. Well was then shut-off until 9-1-83.Well was re-opened at 14:40,9-1-83 and was run continuously until about 22:00,9-3-83. 3.At the separator.These are absolute values calculated from gauge pressure plus atmosphere pressure which was assumed to be 0.96 bars. 4.Determined from the collection pressure assuming liquid-vapor equilibrium (Keenan et al.,1969). 5.Steam fraction calculated using a BHT=193°C and reservoir enthalpy value of 821 kJ/kg (Keenan et al.,1969). \lley test well ST-1,Samples? tr unless specified). 'ipe Ru Steam Condensates Ru767ana48 77 13 13 <0.01 0.04 <0.01 <0.01 <0.01 <0.01 1420 2456 2.3 6.4 301 307 0.1 0.9 0.1 0.1 0.2 0.1 0.2 0.2 0.05 <0.05 <0.05 <0.05 «0.05 <0.05 175 181 0 0.5 <0.1 0.2 40.1 0 3.3 3.1 <0.05 <0.05 <¢0.05 <0.05 <¢0.05 <0.05 ----5.6 6.3 7.0 ---- 1200 4220 11 1.5 <0.1 <0.1 <0.1 <0.1 402 395 1 1 1 1 1 2 77 78 0.8 0.8 0.6 0.6 0.9 0.5 14.5 15.0 --------4.55 4,65 3.58 3.61 -------- 1/2/83 9/3/83 8/24/83 8/27/83 9/1/83 9/2/83 9/2/83 9/3/83 irveys,M.A.Moorman,analyst. Detection Levels Table 3.Chemical Analyses of Makushin Valley test well ST-1,Samples Hot Water Corrected to Reservoir Values (concentrations in milligrams/liter unless specified) 71 74 75 76 77 Average Cations Li 9.4 9.4 9.5 9.1 9.4 9.4 Na 1817 1782 1777 1725 1822 1785 K 234 248 237 226 230 235 Cs 1.2 1.2 1.2 1.3 1.3 1.2 Mg 0.2 0.1 0.1 0.1 0.1 0.1 Ca 128 123 124 116 131 124 Sr 2.1 2.0 2.5 2.3 2.4 2.3 NH,----------------<1.0 <1.0 Anions HCO,<5 <5 <5 <5 1.0 45 so 78 76 75 70 73 74?7.3 7.2 7.1 6.7 7.3 7.1 cl 3140 3130 3090 2930 3060 3070 Br 12 11 11 11 12 ll sio 294 296 300 278 293 292H,8 ----2.4 1.3 ----_---1.9 B 58 57 57 54 56 56 Trace Al -------- --=----0.02 0.02 As 10.6 9.7 11.2 10.5 10.7 10.5 Fe ----------------0.12 0.12 TDS 5782 5740 5696 5426 5694 5668 Date Sampled 8/27/83 9/1/83 9/2/83 9/2/83 9/3/83 Table 4,Makushin Valley test well ST-1,Oxygen and deuterium isotope analyses -steam and water. (parts per mil with respect to SMOW) Sample #Water Steam pecs vuscs pate v/H (smu)80/18 ¢smyy 180/18 (uses)py csmuy 180748 csmuy !8074%0 uses) -9.2 71 \8/27/83 -9.5 -9.1 -96 -13.4 _-9.9 _-9.3 _-98 _=13,5 -79 x= 9.7 x =79.2 y=797 -13.9 x =713.45 -10.0 -9.5 -13.0 1h 2 9/1/83 _-10.1 _-945 _H13.4 -77 x =7-10.05 x =79.5 -90 -13.2 x =-13.05 -13.1 -13.1 75 3 9/2/83 -10.0 -9.6 -90.5 -13.3 -13.0 _ =9.9 -9.6 _ =90 =13,3 _13.0 -77.5 x =-9.95 x =-9.6 y =-90 x =-13.2 x =-13.05 -8.4 -9.6 -13.1 -12.9 1%9/2/83 8.4 9.6 _=13.2 _=12.8-17.5 x=-8.4 x =-9.6 -87.3.x =-13015 x =712.85 -9.6 7 5 9/3/83 -9.6 9.7 -13.0 _=10.0 _=9.6 _13.0 -77.6 x=-9.8 x =-9.6 -88.3 -13.1 x =-13.0 SMU =Southern Methodist University,Stable Isotope Laboratory,R.Harmon and J.Borthwick,analysts. USGS =U.S.Geological Survey,Menlo Park,C.Janik,analyst. Table 5.Makushin Valley test well ST-1,stable isotope analyses corrected to reservoir conditions (parts per mil with respect to SMOW) ne 74 75 76 77 Average D/H (SMU)-81 -78.5 -79 -78.5 -78.5 -78.5 185/18 (smu)-10.3 -10.4 -10.3 (-8.8)°-10.1 -10.3 1857/16 (ys¢s) 10.2 9.9 -10.0 -9.9 9.9 9.9 a)A slight amount of chloride was detected in the #71 condensate indicating incomplete separation. Analyses for 71 were therefore not included in the average. b)Suspect value;not used in computing average. Table 6.Makushin Valley test well ST-1,gas analyses,mole %without H,0° Sample #Collection DGGS USGS Date T,°C Xg co,H,S NH,He H,Ar 0, 49 -7/20/83 121 0.113 89.70 1.23 1.03 0.0006 0.53 0.089 <0.0001 64 -8/24/83 137.5 0.924 79.91 1.44 7.62 <0.0001 <0.0001 0.100 2.03 71 1 8/27/83 120 0.066 88.03 2.02 0.89 0.003 0.254 0.161 0.003 74 2A 9/1/83 135.5 0.082 90.08 2.21 0.24 <0.0001 0.361 0.096 0.033 75 3B 9/2/83 134 0.071 92.64 2.19 0.31 <0.0001 0.169 0.065 0.002 76 4B 9/2/83 147.5 0.103 93.30 1.83 0.24 0.001 0.112 0.067 0.0007 77 5A 9/3/83 147.5 0.098 93.34 2.02 0.22 0.002 0.094 0.067 <0.0001 a)C.Janik and D.Sheppard,U.S.Geological Survey,Menlo Park,analysts. Xg =ratio,moles gas to moles gas plus steam in %.bdPPPnwoon Table 7.Makushin Valley test well ST-1l,mass % gas content of total discharge. steam mass %gas mass %gas content, Sample #fraction in steam total discharge 1 0.144 0.15 0.022 2A 0.116 0.19 0.022 3B 0.119 !0.17 0.020 4B 0.093 0.25 0.023 5A 0.092 0.23 0.021 Partial pressure co,in solution. mole fraction Sample #co,in total fluid?PCO,s bars? l 8.366 x 107 0.54 2A 8.568 x 10_;0.56 3B 7.827 x 10 0.51 4B 8.936 x 10-2 0.58 5A 8.415 x 10 0.55 a)Computed from co,=XCcO,,Xg Xs 1 +Xg Xs where XCO,and Xg are the CO,and gas fractions from Table 6 and Xs is the steam fraction from Table 1. b)Computed from PCO, bars/mole fraction at T =193°C). =Kh XCO,where Kh is Henry's law constant (6500 Table 8.Makushin Valley test well ST-1l,Unalaska Island,Alaska,sulfate/water isotope temperatures . Date Temp Sample #Collected Sep,°C MVIW-2 9/01/83 135 MVTW-3 9/02/83 134 MVTW-4 9/02/83 148 MVTW-5 9/03/83 148 580 (so > -3.76 -3.42 -3.44 -3.29 s'°0(H,0) -9.47 -9.58 -9.61 -9.61 a)C.Janik,U.S.Geological Survey,Menlo Park,analyst. Calculated Temp °C 244 235 238 235 Sample # DGGS USGS 49 -- 64 -- 71 1 74 2A 75 3B 76 4B 77 5A Ave.chem. Table 9.Makushin Valley test well ST-1, chemical and isotopic geothermometers Gas a)See Fournier (1981)for review of chemical geothermometers. b)Gas geothermometer of D'Amore and Panichi,1980,using PCO c)Hy 2 S geothermometer of D'Amore and Truesdell,estimated from Water 18Qz -Sid Na-Ca-K Na-K 6-0 (H,0-SO,)(b) -------------233 218 227 238 ------- 208 224 240 ----227 208 229 247 244 235 209 227 243 235 214 204 225 241 238 203 208 223 238 235 200 207 226 242 238 -<- =0.54 bars. their Figure 8. Table 10.Makushin Valley test well ST-1l,Unalaska Island,Alaska,carbon isotope analyses,co,in gas and steam . Sample #Date Collected T,°C Sep 6 Cone MVTW-1 8/27/83 120 -13.34 MVTW-3 9/02/83 134 -13.45 MVTW-4 9/02/83 148 -13.30 MVTW-5 9/03/83 148 -13.26 a)C.Janik,U.S.Geological Survey,Menlo Park,analyst. Table 11.Makushin geothermal area,carbon isotope analyses,fumaroles and hot springs 13LocationDataCollected+3)CopR fF #2 1982 -11.65fF#3 1982 -10.2 fEH4 1982 -12.37 £FHS 1982 -12.47£FHG6 1982 -10.07 Spring G-j 1983 -15.47 Spring G-p 1983 -13.67 a)L.White and W.Evans,U.S.Geological Survey,Menlo Park, analysts. b)J.Welhan,Scripps Inst.Oceanography,La Jolla,analyst. O7.O'u STATE OF ALANS IB foe enente covmon DEPARTMENT OF NATURAL RESOURCES oe ANCHORee ALASKA 99510PHONE:(907)27DIVISIONOFGEOLOGICAL&GEOPHYSICAL SURVEYS 907-68 PTAA) OQ P.O.BOX 80007 COLLEGE,ALASKA 99708 PHONE:(907)474-7147 June 24,1983 Patti DeJong Director of Project Evaluations Alaska Power Authority 334 West 5th Avenue Anchorage,Alaska 99501 Dear Patti, Attached is the copy of the Phase 1B Final Report by Republic Geothermal, Inc.along with my review of this report.I appreciate the opportunity to review this interesting report and I hope my review is not too late to be helpful to both you and Republic Geothermal,Inc. In general,there is still a lot we do not know about the geothermal resources of Makushin,but our efforts have increased our knowledge about this resource greatiy.Believe it or not,my own attitude still is that we are not looking at just one hydrothermal system and that the developable part of this system(s)is indeed several kms deep. Knowing my luck,the drilling this summer at Makushin will probably prove me wrong (Let us hope it does!). I have been officially removed from geothermal by the "powers to be" in Fairbanks,but unofficially I am still working on Unalaska geothermal. Independent of these changes,please do not hesitate to contact me if you ever have any questions about geothermal,especially with respect to Unalaska.I have and always will enjoy working with you and naturally I will always have time to talk about Unalaska. Cordially, o ""7 John W.Reeder,Ph.D. Geologist cc:Don Markle,Special Geothermal Consultant to APA Proj.Code: File Code:38.OT.ORD | J.pete 83.1785./| P Os) dune 13,1983 Dr.Gerald Hutterer Republic Geothermal,Inc.11823 E.Slauson Avenue Santa Fe Springs,California 90670 Dear Dr.Hutterer: Attached are the final comments on the Unalaska Phase 1B Final Report.I have attached Dr.Economede's review comments for your consideration as well.I would like to thank you on behalf of theAlaskaPowerAuthorityforawelldonereport..The thoroughpresentationoftheworkcompletedtodatewillbeusefulfor generations. As we discussed last week,due to the length of time taken by myself in forwarding comments on the report to you,the submitted date for the final report is hereby extended to July 30,1983. . ,Sincerely, FOR THE EXECUTIVE DIRECTOR Patti DeJong Director of Project Evaluation Attachments as stated. 9122 "Prol.Code: File Code:o3e.OF 22 | J.Deter BB.LOY.(: ,,7 [eeJniversityofAlas.a ° PETROLEUM ENGINEERING DEPARTMENT ROOM 17,DUCKERING BUILDING FAIRBANKS,ALASKA 99701 PETROLEUM ENGINEERING re (907)474-7734 May 25,1983 Ce Pee LUT Ms.Patti DeJong Alaska Power Authority 334 W.5th Ave. Second Floor Anchorage,AK 99501 Dear Ms.DeJong: The following comments are cursory observations on the Republic Geothermal Report.We have not had the time to do an indepth examination in view of the fact that we have had the report for only a few days before the critique was due.Hence,this list is not as complete as we would have wished. Page 19,second paragraph:Fumarolic activity in the Aleutian Islands has been found to vary with the time of year (season)and also with the barometric pressure;intense fumarolic activity is common during the spring when barometric pressure is low. Page 36,last paragraph:The report states that "the limited size of the Driftwood BayValleyandFumaroleField8mercuryanomaliesindicatesthattheydonothavemajorgeothermalsignificance."But,Republic recommends in Executive Summary (page 2) that a 2000 foot hole be drilled near Sugarloaf Cone.This would mean drilling a well in an area which is known to be of low potential. Page 40,first paragraph:The report states that "the pluton was sampled at eight places so as to obtain reasonable geographic and statistical representation."Eight locations is not statistically valid.Many more locations should be examined to yield valid, reproducible results. Page 44,last paragraph:"The graywackes contain alteration mineral assemblagescharacteristicofgreenschistmetamorphism(calcite,with intense chloritization)." Actually,chloritized calcite is not always indicative of greenschist facies.Rocksconsistingofquartz+calcite ++illite (phengite)persist unchanged from diagenesisthroughmedium-grade (amphibolite)metamorphism,and the assemblage calcite +quartz persists to even higher grades.The mineral assemblage which is actually characteristicofgreenschistmetamorphismischlorite+zoisite/clinozoisite +actinolite +quartz. -- annPrey.COULL oe eecronBLO2.0R- Ms.Patti DeJong May 25,1983 Page Two (2) Page 45,last paragraph:The composition of the Makushin voleanies actually ranges from basalt to dacite,and not just from basalt to andesite. Page 46,second paragraph:The report states that the widespread areal distribution of meteorie and snowmelt-derived waters,"coupled with the vertical permeability in some areas,could easily facilitate recharge of the geothermal reservoir."However,it takes thousands of years to reach the temperatures of geothermal reservoirs.Furthermore, the net heat recharge is less than 0.6%of the current heat production rate at The Geysers (see Section Two,Economides et al (1983)).Therefore,geothermal reservoirs cannot be construed as renewable resources. Page 46,last paragraph:The report states that "pyroclastic flows have been mapped near Fumarole Field 1".The deposits are not pyroclastic flows,but rather voleanic mudflows (lahars).This is significant since pyroclastic flows are much more dangerous. Also,the report states that Sugarloaf Cone "is still virtually uneroded",when in fact theconehasbeensubjectedtosignificanterosionwhichformedthegentleslopesandroundedsummit. Page 47,first paragraph:The text states that the plateau near Fumarole Field 1 is covered by "successive accumulations of ash approximately 100 meters thick."This is unlikely,for nowhere on Unalaska Island are there accumulations of ash which even approach a thickness of 100 meters.The thickest deposits are between 10 to 15 meters thick. Page 72,first paragraph:"The meteoric waters percolate downward into the diorite andareheatedbyconductionfromamagmaatdepthtoatemperatureover200°C."This is the same recharge problem as noted on Page 46. Page 134,last paragraph:"Stable isotope concentrations reveal that meteoric waters originating on the flanks of Makushin Voleano recharge the reservoir."Same problem noted on Pages 46 and 72. Page 125,Total Data Integration (Commentary on sources of the data presented): 1.New data contributed by RGI. 2.Already known from Motyka et al (1981)and Reeder (1982).3.Already known from Plate 77 of Drewes et al (1961). 4.New data contributed by RGI. 5.New data contributed by RGI.6.Already known from Reeder (1982). 7.New data from RGI. 8.New data. 9.New data. 10.Already known from Drewes et al (1961)and Reeder (1982).11.Already known from Arce (1983).Also,Tabletop Mountain and Wide Bay Cone are comagmatie with the rest of the voleanie rocks on Unalaska Island (Swanson, 1983). 12.Already known from Reeder (1982). University of Alaska,Petroleum Engineering Department,Room 17,Duckering Building,Fairbanks,Alaska 99701 Ms.Patti DeJong May 25,1983 Page Three (3) 13.Already known from Motyka et al (1981). 14.Already known from Motyka et al (1981). 15.Already known from Motyka et al (1981,1983). 16.New data from RGI. 17.Irrelevant. 18.New data from RGI. 19.New data from RGI. Emphasis should be placed on data acquired through the thermal gradient holes. From an editorial viewpoint,they should be up front in the listing of the conclusions. We will be happy to submit a further critique. Sincerely, PF ni -» Michael J.Economides Assistant Professor Petroleum Engineering Department MJE:bb University of Alaska,Petroleum Engineering Department,Room 17,Duckering Building,Fairbanks,Alaska 99701 DEPARTMENT OF NATURAL RESOURCES DIVISION OF GEOLOGICAL &GEOPHYSICAL SURVEYS May 20,1983 VEor ain,2.Ms.Patricia DeJong ","5 8AlaskaPowerAuthorityMYDares, 334 West 5th Avenue "st LUT on, Anchorage,Alaska 99501 Dear Patti: Ale Ol AILNSIAA i ag O7-dR j Rewiewr|SHEFFIELD,GOVERNOR 1&6 /QO POUCH 7-028/ANCHORAGE,ALASKA 99510 PHONE:(907)274-9681 P.O.BOX 80007 COLLEGE,ALASKA 99708 PHONE:(907)474-7147 This is in response to your request for comments on the Republic Geothermal, Inc.(RGI)Phase IB final report,"The Unalaska Geothermal Exploration Project",First Draft.As you know,DGGS and RGI have been in close communication over the past several months regarding the interchange and interpretation of data.We've learned much through discussions with RGI scientists and have modified many of the interpretations presented in our own initial report.These changes have been incorporated into a revised version of the geothermal fluids study,which will be issued shortly as a DGGS Report of Investigation, Although we are in mutual agreement on many aspects of the Makushin geothermal system,significant and spirited debate still persists with regard to interpreting some of the data.These disagreements are reflected in the numerous comments I've pencilled into the margins of RGI's report,My con-mentary is restricted to the main text and concentrates primarily,the geo thermal fluid chemistry and thermal models,areas with which I am most familiar.To expedite matters I have sent the original copy of my comments directly to RGI;a xerox copy of these comments is enclosed for your review. For the most part,I found the report to be a well-organized,comprehensive summary and synthesis of data relating to the Makushin geothermal resource. Several parts were particularly good: thermal areas including the sketch maps3 1)the detailed descriptions of the 2)the descriptions of the thermal gradient holes,core lithology,and interpretation of hydrothermal alteration minerqlogy;and 3)the results of Dr.Bamford's geochemical studies. RGI's synthesis of geologic maps has brought out areas of controversy and deficiency,particularly as regards faults and contacts --problems we hope to address this coming field season. RGI has made a good case for the siting of the deep test well,the type of drilling and the well-testing to be performed. Proj.Code: Fite Cede:Sf,97.08 | J.date:BS.1YO,1| Ms.Patricia DeJong -2-May 20,1983 Some specific criticisms: 1)RGI's discussion of Cl-Mg springs in lower Glacier Valley must examine alternate possibilities for the source of Cl in the waters.We are in strong disagreement as to whether the geochemical and isotopic data indicate mixing with deep Cl-rich hot waters. 2)I object to the way the Silicon mixing model is being used in this report (see attached). 3)I disagree with RGI's manner of interpreting thermal gradient hole temperature data to support their heat source hypothesis (see attached). 4)No mention is made of a direct indication of minimum reservoir temperature,namely that the superheated fumarole originated from a source >190°C (a temperature deduced without drilling any holes,I might add). I have enclosed a copy of a preliminary report by Prof.Sam Swanson from the University of Alaska on the "Petrology of the Makushin Volcanic Field, Unalaska Island,Alaska".In this report,Prof.Swanson presents arguments for the existence of a single shallow-lying magma body underlying the Makushin Volcanic Field.This interpretation differs from an earlier one made by Reeder and Langmuir.Prof.Swanson,who bases his judgement on the much greater data base that is now available,is in contact with Dr.Langmuir,and they hope to collaborate on a mutually acceptable model for the volcanic system at Makushin. Should you have any questions regarding my comments on RGI's report,please do not hesitate to call. dnf MeRomanJ.Motyka Geologist Enclosure ec.G.Huttrer,Republic Geothermal,Inc. A note on the use of the Si0,mixing the model (pg.59): I found the only way to generate RGI's results was to assume no steam loss and to use 87 ppm S10,concentration (RGI analysis,table 6)for the : "mixed"water (see attached graph).All DGGS analyses of the Cl-spring waters show Sid,concentrations of 100 ppm or greater.Note that because of the implications for reservoir temperature we take particular care in our Si0, determination.At least two and sometimes three analyses are'performed on z, separate samples to check consistency of results.oo / If 100 ppm is used for the SiO,concentration in the mixed water,the2 mixing line does not intersect the quartz solubility curve.Also,because of the steep slope,this particular mixing line is very sensitive to the choice - made for temperature and Si0,concentration for the cold water fraction.I think it is very misleading for RGI in this instance to present the results of the mixing model analysis without alerting the reader for possible pitfalls and without offering a more detailed explanation 'of how the results were obtained. The USGS does not ordinarily use geothermometer temperatures predicted by Si0,mixing models,unless a linear trend is shown between either or both spring temperature vs.Cl concentration and §D vs.Cl (USGS Circ.790). Neither of these trends occur in the Glacier Valley Cl-spring waters nor is 2 deep water were mixing with cold waters. there an increase in Si0,with Cl as would be expected if a Sid,-rich I have taken particular exception to the application of the SiO,mixing model because of RGI's repeated use of the results of this analysis in later discussions as an indicator of a subsurface Cl reservoir,its temperature and chemistry. 50 ESTIMATING TEMPERATURE,HOT-WATER COMPONENT IN MIXED WATER TPrryprrrrperrrprrrrperrrprryrvprrryr yt Lh700 600 500 400 300 SILICA,INMILLIGRAMSPERKILOGRAMboulilipelooblibtURIRENEEMERERORSEEDSROPEEEOORRODSEESOOSPRESBORESPRESEREERs| 200 i. A ! tJ {o?ie> a \©100(ep) O | Qa - er t-.= 9 M1 11 bparrdiritphitrrptlorrorallyt Lis O 1 100 -200 .300ENTHALPY,IN INTERNATIONAL TABLE.CALORIES PER GRAM FIGURE 1.-Dissolved silica-enthalpy graph for determining temperature of a hot-water component mixed with coldwateryieldingwarmspringwater.. steam is assumed to have escaped before mixing is intersected (point F in fig.4).Point F gives (point E for 100°Cin fig.4).the enthalpy of the hot-water component before3.Move horizontally across the diagram parallel to.the onset of boiling,and point G gives the orig-the abscissa until the maximum steam-Joss curve,.inal silica content before loss of steam occurred. Notes on paragraph two,pg.132. ."f . , : The data may suggest your conclusion that E-1 is horizontally closer to the heat source,but I disagree that it requires it. 1) 2) 3) 4) The elevation of D-1 is 600 ft.higher that E-1,and this must be taken into account.4 Isothermal conditions ( 10°C)prevail to a depth of nearly 800 ft.at D-1,presumably as a result of cold water circulation in vertical frac- tures.Similar temperatures extend to depths of only 100 ft.at E-1l. The 10°C temperature boundary is therefore at a much greater depth in D-1l than at E-l.The location of the cold water temperature boundary and the rock type areconditions which influence the temperature profile.Any comparison must take these factors into account.| The thermal regimes in the two holes are distinctly different.The temperature profile in D-1 appears to be predominately controlled by convection while most of the E-1 profile indicates conductive heat transfer.These differing heat transfer mechanisms must also be taken into account. Temperature profiles can be readily modified by convection of hotter or colder waters.Such convection can easily mask the presence (or non- presence)of a heat source. ceU-2@ EK- F%2 u-25-K-E2 "(>3)RE LM ont CZY-22 -€2 ?/ UM-2%3-K -2 2 B-17 C2-Uyy THE UNALASKA GEOTHERMAL oo. EXPLORATION PROJECT PHASE IB FINAL REPORT Prepared by . Republic Geothermal,Inc.f for The Alaska Power Authority -First Draft - April 30,1983 8}yrTABLE OF CONTENTS EXECUTIVE SUMMARY '. «oe @¢¢©@ @¢@ ee @#@ ©@ @ &#®©©©©©©@©@ ©&@ @©&@ INTRODUCTION.2.1 wee ee ee ee wt et te Seeeeee STAGE III -LAND AND ENVIRONMENTAL FIELD WORK A.-Wellisite Selection Data Collection «es e@ @ @ @ ©©@ @ &©@ @&©@ B.-Environmental Baseline Data.....eeeeee STAGE IV -FIELD EXPLORATION..2...2...22.2 ew ee ee we ew ew wee A.Geology..2...2 2.52 eeeer B.Geochemistry ce ee we we ww th ttt ht tt tht ew -oe C.Mercury Soil Survey.........-6.2.2000.(Ce ee ees D.Self-Potential Survey...2...2 2 ew ew ee ew ew we eee STAGE V -DATA COMPILATION AND TEMPERATURE GRADIENT "HOLE PROGRAM PLANNING .2.2.2.1.2 2 ww ee we ww we ew ene A.Geology.6...eee ee ee ee eee teeweeee 1.Petrographic Studies.2...1.6 1 ww we ew ww we ee 2.X-ray Diffraction Analysis and Interpretation ofHydrothermalAlterationZones...2...2 2 2 ee eee 3.Geologic Summary...0:2.2 we ee ew we te te we ww ae a.Lithology.......Pe ee ee b.Geologic Structure...2...2 ee ee ew ee ewewee B.Geochemistry ..2...2.2 2 ee we we wwe toeeeee. 1.Chemical Analyses cee ee we we we ee ee ee te ee 2.Classification..2...2.2 2 2 ee ww we ew ee ee we 3.Water Chemistry .2...2.2 2 2 we ew ew we we we we we 4.Reservoir Type..6 2 6 ee we we we ew ee we ew ee es TABLE OF CONTENTS,(continued) 5.Reservoir Temperature.........22-6."Te ee ee 6.Isotopic Composition of Fluids.....2.242.222 02. 7.Gas Chemistry ..2...2 2 ee ee ew ew ew we we bee 8.Summary .2 2 2 eww ee we we ee we tw tt we wwe C.Geophysics ..22 ee ee ee ee ee ee eee 2 FF arD.Refined Geothermal Resource Model |.J.oe ee E.Temperature Gradient Hole Site Selection ........2.. F.Temperature Gradient Hole Drilling Program......mee G.Permit Approvals ..2...2.2 we ww ew we wwe we ew ew we ww H.ODrilling Program Logistics ...2...2.1.2 2 ee ww ew we ee Z 1.Helicopter Support..2...2 2 2 ee ee ee ee ee we i 2.Drilling Equipment and Personnel..7...2.22220 3.Camp Facilities and Operation.Doeeeeeeeee 4.Communications a a rs STAGE VI -TEMPERATURE GRADIENT HOLE DRILLING.....2-22.22ees A.Move In and Rig Up .2 2 2 0 ww we we we ww ww ee ww B.Orilling Supervision se ee we ee we tw tt ww tt tw C.Data Acquisition .2...6.6 ew we ee we ewe et ee we D.Environmental Monitoring....2.2.2.2.2 ee ee eee eee STAGE VII -DATA SYNTHESIS AND DEEP WELLSITE SELECTION....fe ees A.Analysis of Data from Temperature Gradient Holes ....... 1.Temperature Gradient Hole D-1 .....2.2.22.2+.2.24064648-48 4 2e TABLE OF CONTENTS,(continued) 3.Temperature Gradient Hole 1-1 ce ee a B.Aerial Photograph Interpretation ..........2.2.2:i6 6 C.Gravity Data.:ce ee ee tw we te tt th tt th et D.Tota?Data Integration ..2...2.2.2 we we ew we we ew we ee -E.Geothermal Resource Model Refinement II.........2..2. F.Resource "Target”Identification ..2...2...2 ee we wee G.Deep Wellsite Selection........-.20-0080ceeeee H.Deep Exploratory Well Drilling Program....°.....2.22-. l.Preliminary Deep Well Testing Program.........a : 1.Ory Steam Resource..2.2 2 ee ew ew ew ew wwe wwe 2.Hot Water Resource.........me eee ee .eee 3.Preliminary Well Test Cost Estimates......2...2..2..2.. J.Deep Well Budget and Scheduling........-eeeeeee STAGE VIII -DEEP WELL PERMIT ACQUISITION..........224.222.-. A.Fluid Disposal Methods...2.1.2.2.2 0 ee ew we ew ew ww ew B.Environmental Measures .....ee C.Permit Applications..2.2.2 2.2 2 2 0 ©ee ew ew we ew we eww 0.Environmental Documents...2...2.2 2 ee 0 ee et E.Permit Approvals ......+.22s a REFERENCES..2.-..ce wee we Lee eeeeee Vii Temperature Gradient Hole E-1.......2.2....ae ifA):"twonN10 iW 12 13 44 15 16 17 18 LISTOF FIGURES ;Page Fumarole Field #1 and Hot Springs Group #10 .-. -.es 672 Fumarole Field #2 and Hot Springs Group #9.....-13 Fumarole Field #3............eee 15 Fumarole Field#4.........2.000008 nF Fumarole Field#5.........02.-0004 S.ee.18 |_#Fumarole Field #8..........2..-."Se oe ee 20HotSpringsGroup#11 and #12.............22 Fumarole Field #19...1.1 6 we ewe ew ew ew ww wens 24 Cation Ratios in Waters from the ;Makushin Geothermal Area........ee ew ee 55 -Stable Oxygen and Hydrogen Isotopes in Thermal and - Non-Thermal Makushin Geothermal Area Waters ......62 Refined Geologic Model of the Makushin Geothermal Area..2...a a a a .713 Lithology of Temperature Gradient Hole 0-1, Makushin Geothermal Area...2.2.1.1 we we we ew een 93 Temperature Data of Temperature Gradient Hole D-1, Makushin Geothermal Area...2.1.2.2 2 ee ew we wee 101 Distribution of Indicative Geochemical Elements in Temperature Gradient Hole D-1 ......2..+242424+246-.2 102 -Lithology of Temperature Gradient Hole E-1, Makushin Geothermal Area....2.2.2 2 ©2 2 e we ww 104 Temperature Data of Temperature Gradient Hole E-1,© Makushin Geothermal-Area....2...2 we ee we ew we wwe 112 Distribution of Indicative Geochemical Elements in Temperature Gradient Hole E-1 ......4424.2424-ee6-e 113 Lithology of Temperature Gradient Hole I-1,SO Makushin Geothermal Area...2.2.2.0 2 ee ew we wee 115 19 20 2} 22 23 LIST OF FIGURES,(continued) Temperature Data of Temperature Gradient Hole I-1, Makushin Geothermal Area.ce ee et ew eg ew ew ww Distribution of Indicative Geochemical Elements in Temperature Gradient Hole I-]........46.6 ees Lineament Azimuth Frequency Plot, Makushin Geothermal Area...2.1.2 2 2 2 2 eee eee Azimuth Frequency Plot,Makushin Geothermal Area..... North-South and East-West Cross Sections of the Makushin Geothermal Area,with Temperature Data.... vi Photograph Photograph Photograph Photograph Photograph Photograph Photograph Photograph Photograph Photograph Photograph Photograph 10 2 12 LIST OF PHOTOGRAPHS Temperature Gradient Hole D-1 -376 Feet Photomicrograph of Porphyritic Andesite .. Temperature Gradient Hole D-1 -1,239 Feet so ©e @ @ Photomicrograph of Fine-grained Altered Diorite ... Temperature Gradient Hole D-1 -1,386 Feet Photomicrograph of Andesitic Dike .... Temperature Gradient Hole 0-1 -1,429.5 Feet _Temperature Gradient Hole D-1 -1,429.5-reéyyPhotomicrographofAlteredDiorite..fe Photomicrograph of Alteration Minerals in Diorite .. Temperature Gradient Hole E-1 -1,379 Feet Photomicrograph of Diorite....."es ew ee Temperature Gradient Hole E-1 -177 Feet Photomicrograph of Porphyritic Diorite... Temperature Gradient Hole E-1 -616 Feet Photomicrograph of Altered Diar ite oe eeTemperatureGradientHoleE-1 -"781 Feet -«©e@ e@ @ Photomicrograph of Alteration Minerals in Diorite .. Temperature Gradient Hole E-1 -1,220 Feet Core Showing Fractures of Diorite Temperature Gradient Hole E-1 -911 Feet Photomicrograph of Altered Diorite..... Temperature Gradient Hole E-1-1,056 FeetPhotomicrographofMineralizedHydrothermal Veins .. "ova 98 108 W 4eieCnifLIST OF TABLES Page Lithological Samples Collected in the Makushin Geothermal Area.....2.2 ew ow we eee 9 Field Geochemical Methods........2-02e00e0ee 27 Geochemical Field Observations of Makushin Volcano Geothermal Manifestations........ee 28 Mercury Monitoring at a Standard Reference Point.....34 X-ray Diffractometer Analysis of Altered Rocks from Makushin Geothermal Area.......oe ee te we 43 Chemical Analyses of Thermal Waters, Makushin Geothermal Area....2...oe re 5°) Chemical Analyses of Ground Waters,:Makushin Volcano Geothermal Area......2 2 ee ee 51 Typical Classified Thermal Waters........2..4.2424+2. «593 Tentative Reservoir Temperatures Calculated Using Various Geothermometers,Makushin Geothermal Area....58 Stable Oxygen and Hydrogen Values for Waters from | Makushin Volcano Geothermal Area....2.2.2 ese 61 Chemical Composition of Fumarole and Thermal Spring Gases from Makushin Thermal Field,Preliminary Results .64 Temperature Data of Temperature Gradient Holes, Makushin Volcano Geothermal Area......2.2...100 Roosevelt Hot Springs KGRA,Utah Geothermal Reservoir Field..2.ew wee we we ewe ww wes oe es ee)6995 iv GPAppendix A Appendix Appendix Appendix Appendix Appendix Appendix Appendix Appendix Appendix Appendix Appendix Appendix _Appendix Appendix B LIST OF APPENDICES 1982 Environmental Baseline Data Collection Program Final Report Final Report of the Geotechnical Reconnaissance:Access RoadsandDrillPadPreparation Self-Potential Survey,Makushin Volcano Area,Unalaska Island,Alaska Detailed Description of Thin Sect ions From Surface LithologySamplesandAnX-ray Diffraction1 Analysis of Samples M-2throughM-28 iovA Chemical Analyses of Makushin Volcano Area Watefs,UnalaskaIsland,Alaska Drilling Program,Unalaska Temperature Gradient Holes Permit Applications and Approvals for 1982 Field Operations Permit Compliance Correspondence for 1982 Field Operations_ Temperature Gradient Holes D-1,E-1,and I-1 Drilling Histories Geochemical Logging of Cuttings and Core Samples from Drill Holes 0-1,E-1,and I-1,Makushin Volcano Geothermal Prospect,Unalaska Island,Alaska Drilling Programs for Preduction-Size Deep Exploratory Well, $ma11-Diameter Geothermal Exploratory Well,and Temperature Gradient Hole Budget and Schedule for Phase II Projects Permit Applications for 1983 Field Operations Correspondence with Native Alaskan Corporations for 1983 Field Operations Permit Approvals for 1983 Field Operations vidi Plate Plate VII VIII IX LIST OF PLATES (in pockets) Geothermal Manifestations in Makushin Volcano_Geothermal Area,Unalaska Island,Alaska Geology of Northwestern Unalaska Island,Alaska Makushin Volcano Area Mercury Soil Gas Survey Unalaska Island,Alaska Self-Potential Survey Lines and Contours Makushin Volcano Area,Unalaska Island,Alaska Geologic Map of Unalaska,Makushin Volcano Area, Unalaska Island,Alaska Geologic Cross Sections,Makushin Volcano Area,Unalaska Island,Alaska Drilling Locations,Makushin Volcano Geothermal Area, Unalaska Island,Alaska Air Photo Lineament Interpretation,Makushin Volcano Geothermal Area,Unalaska Island,Alaska Unalaska Complete Bouguer Anamoly Map,Northern Part of Unalaska Island 4x waygeophysical,and temperature gradient drilling activities.:LeEXECUTIVE SUMMARY Republic Geothermal,Inc.(Republic)has been selected by the Alaska Power Authority (APA)to explore for geothermal resources on Makushin | Volcano,Unalaska'Island,Alaska,under the terms and conditions of Contract CC-08-2334.Phases IA and IB of Republic's exploration program were con- ducted in 1982 and Phase II will be undertaken in 1983.This final report describes and summarizes the Phase IB environmental,geologic,geochemical,Vie , 27 The environmental work centered about the acquisition of Kaseline data regarding water quality,freshwater aquatic biology,terrestrial habitat quality,and cultural resources.The information obtained was used in prep- aration of permit applications and in helping determine optimum drilling sites. The geologic work comprised field mapping of surface geology,geothermal features,alteration zones,and tectonic structure.The work was accomplished by Republic geologists in cooperation with Alaska Division of Geological and Geophysical Surveys (DGGS)scientists and included the acquisition of color and black and white aerial photographs plus preparation of a large-scale topograpnic map of the interest area.As a result of this work,the known areal extent of the dioritic stock was greatly increased,and fifteen newthermalmanifestationswerediscovered. Geochemical field work was also conducted by Republic in cooperation with the 0GGS.Several thermal and nonthermal waters were sampled and analyzed so as to identify discrete groundwater and hot water regimes and to help develop a geothermal system model.Additionally,'Republic conducted a mercury soil survey in and around the Makushin Geothermal Area.”This study resulted in the delineation of six anomalies having mercury soil concentrations in excess of 324 parts per billion (ppb). A Self-Potential survey was determined to be cost-effective;therefore,a study covering about.78 line-kilometers was accomplished under Republic supervision.Two of the highly anomalous zones that were detected wereinterpretedtobeindicativeofsubsurfacegeothermalresources. Analysis of all of the geologic,geochemical,geophysical,and environ- mental parameters,together with consideration of logistical constraints, resulted in the identification of three primary temperature gradient hole drilling sites.Temperature gradient holes 0-1,E-1,and I-1 were drilled to'nominal depths of 1,500 feet using a diamond core rig.Highty*4noma lousthermalgradientsrangingupto24°F per 100 feet were recordéd as were temperatures of up to 195°C (383°F). Republic and DGGS personnel together developed a model of the Makushin geothermal system based on the data acquired.It is believed that the resource is water-dominated,that it may be overlain locally by a steam cap, that it is located predominantly on the eastern flank of Makushin Volcano, that reservoir temperatures are in excess of 250°C,and that the depth to the reservoir will be less than 4,000 feet.a Based on the encouraging results of the Phase IB work and the geothermal model derived therefrom,Republic has recommended that Phase II consist of a deep exploratory well to be drilled to a depth of approximately 4,000 feet near the site of temperature gradient hole E-1,and a shallower hole to be drilled to a depth of approximately 2,000 feet near Sugarloaf Cone.The deep well is intended to penetrate the geothermal reservoir,while the shallower hole is meant to seek the limits of the resource. Since completion of the field work,Republic has analyzed the data com- piled,planned Phase II work,applied for relevant permits,and prepared this report. THE UNALASKA GEOTHERMAL EXPLORATION PHASE IB FINAL REPORT 7 ; Introduction Unalaska Island,situated approximately 900 miles southwest of Anchorage, Alaska,belongs to the Aleutian archipelago.It is composed predominantly of extrusive and intrusive igneous rocks and sediments derived therefrom.TheyoungestigneousrocksarelavasextrudedfromtheactiveMakushinVolcano. 'Geologic mapping of the island revealed the existence of numerous fumarolesLandhotspringsthatappearedtoreflectasignificantgeothérmalresource at depth. Because the towns of Unalaska and Dutch Harbor project significant growth - in the near-term future and because high-cost diesel o11 is currently used to fuel the towns'electric power producing generators,a project was initiated to determine the feasibility of cost-effectively generating electricity using geothermal energy from the eastern flank of Makushin Volcano. In early 1981,the Alaskan legislature authorized the expenditure of approximately $5,000,000 for geothermal exploration on Unalaska and delegated project responsibility to the Alaska Power Authority (APA).In November 1981,Republic Geothermal,Inc.(Republic)was awarded Contract CC-08-2334 to undertake the project with Dames and Moore of Anchorage as prime subcontrac- tor.Initial contracts were executed in January 1982. The exploration program proposed by Republic and accepted by the APA has two phases.Phase I was to be completed in early 1983 and Phase II was to be finished in early 1984.Phase IA comprised data review,a technical planning meeting,data synthesis,and detailed planning for Phase IB.Phase IB in- cluded efforts related to geologic,geochemical,geophysical,drilling, environmental,and permit acquisition activities.Phase IA encompassed Stages I and II (Data Review and Technical Planning Meeting;and Data Synthesis and Detailed Planning).Executed as part of Phase IB were Stages f III through VIII (Land and Environmental Field Work;Field Exploration;Data Compilation and Temperature Gradient Hole Program Planning;Temperature Gradient Hole Drilling;Data Synthesis and Deep Wellsite Selection;and Deep Well Permit Acquisition). ) The Phase IA report was submitted to the APA on April 30,1982.It is hereby incorporated with and made a part of the Phase IB Final Report pre-.sented below.The document that follows describes,in turn,af}of the )-activities in Stages III through VIII as mandated in snendnent*No.3 to Contract CC-08-2334./ The report has many authors,including members of Republic's Exploration, Production,and Land Department staffs and representatives of Dames and . Moore's Anchorage and Seattle offices.Their cooperation and diligence as well as that of scientists of the Alaska Division of Geological and Geo- physical Surveys (DGGS)4s acknowledged and greatly appreciated by the a Project Manager. ih70NALiSSTAGE III -LAND AND ENVIRONMENTAL FIELD WORK A.Wellsite Selection Data:Collection Because of the logistical and geological constraints placed on the selection of temperature gradient hole locations and deep well sites atUnalaska,environmental and geotechnical information was expected to play only a "fine-tuning"role in the actual wellsite selection process.However, with the decision to evaluate potential temporary access road adignments to"the alternative 1983 deep wellsites,both environmental and "geotechnical information became much more important.Accordingly,two complementary programs were undertaken during the 1982 field season to provide the environmental and geotechnical information appropriate to the temperature gradient hole,deep wellsite,and,most importantly,temporary access road route selection processes. The "1982 Environmental Baseline Data Collection Program Final Report"(Appendix A)presents,jin part,environmental information regarding water quality;freshwater aquatic biology;terrestrial habitat quality and threatened,rare,or endangered species;and cultural resources.This report was valuable in the process of selecting environmentally sound temporary access routes to the proposed 1983 deep well location."The Final Report of the Geotechnical Reconnaissance:Access Routes and Drill Pad Preparation" (Appendix B)identifies technically feasible access road alignments and provides rough estimates of the construction costs,time,and problems .associated with constructing the access roads and well pads.Because the decision was eventually made to conduct the 1983 operations without the use of access roads,the environmental and geotechnical data collected specifi- cally to assist in the siting of these access routes became academic,but still can be used in the future should additional operations be contemplated. B.Environmental Baseline Data la In accordance with the 'Alaska Power Authority contract,Republic requested Dames &Moore to design and implement an environmental baseline data collection program that could:1)provide data useful in the location and design of proposed operations;2)acquire that environmental information which is,or may be,required by permit-issuing agencies or other interested parties;and 3)establish an environmental data base upon which to judge the _impacts of operations..;wfVa Dames &Moore based design of the program upon results of an analysis that combined the known (or assumed)characteristics of the area's environ- ment,the potential requirements of the regulatory agencies,and the design and potential impact of the proposed operations.The "1982 Environmental Baseline Data Collection Program Final Report"presents specific information on water quality;freshwater aquatic biology;terrestrial habitat quality and threatened,rare,or endangered species;and cultural resources.Please see Appendix A for the results of the environmental baseline data collection program. iad)' STAGE IV -FIELD EXPLORATION A.Geology - From April 26,1982 through September 8,1982,the geology of the, Makushin Volcano geothermal area was studied in the field by Republic geologists.Work accomplished during the field season included remappingandsamplingofmajorlithologicalunits,collection of hydrothermally ) altered materials,detailed mapping of altered areas,location and charac- terization of all geothermal manifestations in the interest area,and examination of the surface traces of fractures and faults.All of these studies were conducted to refine our understanding of the Makushin Volcano geothermal resource and to allow the identification of the optimum sites at which to drill three 1,500-foot deep temperature gradient holes. Republic's geological field work confirmed that the existing geological maps compiled by Drewes et al.(1961)and by Reeder (1981)were basically accurate.The one major exception was the extent -of plutonic rock in the area.Previous mapping indicated that the plutonic rock was limited to four relatively small outcrops.The 1982 field examination,facilitated by heli- copter access,quickly restudied the complete plutonic outcrop pattern and determined that at least six outcrops of diorite were present,and that these outcrops were part of one large stock,hereafter named the Makushin Stock.The stock is predominantly dioritic in composition and has textures that grade from fine-grained at the intrusive contacts to coarse-grained as the distance from the contacts increases.The essential mineral suite observed in field examination of the diorite includes plagioclase,horn- blende,and pyroxene.Accessory minerals are magnetite,biotite,and pyrite. Additional lithologies studied in the field were recent Makushin Volcano extrusive rocks,young igneous flow rocks derived from satellite vents of Makushin Volcano,and the Miocene Unalaska Formation.These rocks were vy 7 A a”}cad:f tr}.u mei.jv)aby tA /I,.JA,}Rear Maw examined by numerous traverses during which contacts were mapped and closely studied to determine structural positioning,age relationships,and anyadditionalgeologicalinformation. In conjunction with the contact mapping,major lithologies were classi- fied and characterized.Representative samples of major rock types were megascopically studied in the field and selected samples were then shipped to Los Angeles for microscopic study and X-ray diffraction anlaysis.Table 1 lists the samples shipped to Los Angeles,including both the hydrothermal alteration samples that were collected and the fresh rock samples discussed above.Plate 1 illustrates the sampling sites,and Appendix C-1 contains » the detailed microscopic descriptions of the Surface samples.i t</_#f ities gs ft gathers:!”sg chin Cyasfe!*Vhsfs iy:J Ot:iw Own .TT"gatan Ch,{>oar,[ee Republic geologists covered a great deal of terrain while conducting the 1982 field work.During their surveys,emphasis was placed on field identi-fication of faults.Nevertheless,only three significant faults were jiden- 'tified as a result of their observations.All three of these faults are located in upper Glacier Valley (Plate II).The northern-most fault 1s .E evidenced by a one-meter wide,silica-cemented breccia zone oriented ina'Vs (north-south direction within the main river channel.The breccia fragmentsianarepredominantlyangular,altered,yellowish plutonic rock which have beena|completely cemented in a matrix of secondary silica.River erosion has:-.,tf \removed any signs of offset that may have existed;however,field examina-wype"tion suggests the fault plane is essentially vertical..Ne few Gled viie WF fart Boge!at A second fault,located between the northern and southern faults, strikes northeast-southwest and is exposed in the western bank of the river in upper Glacier Valley (Plate II).At this location,evidence for the fault comprises an altered breccia zone that separates Unalaska Formation graywacke froma young,narrow volcanic dike.Field relationships indicate that the breccia zone reflects a nearly vertical fault plane. Oi TABLE 1 ) " LITHOLOGICAL SAMPLES COLLECTED IN THE MAKUSHIN GEOTHERMAL AREA,UNALASKA ISLAND,ALASKA(See Plate I for Sampling Locations) General Location Field Determined Lithology-Notes©Sample # M-1 1 km East of Sugarloaf Cone Quaternary Basalt Hg Stat.38-M-2 Fumarole Field #8 Argillic Alteration M-3 Fumarole Field #8 Fresh Andesite w/pyrite and chalcopyriteM-4 Upper Glacier Valley Fine Grain Plutonic Hg Stat.53M-5 Upper Makushin Valley Altered Quartz and Clay SP Stat.G M-6 Upper Makushin Valley Grey Hornblende Andesite 250m NE of Hg Stat.6]M-7 Sugarloaf Plateau Quaternary Basalt Near Hg Stat.68M-8 Upper Glacier Valley Argillic Alteration SP Stat.E +4900N -M-9 Upper Glacier Valley Plutonic Same as M-8 M-10 East of Sugarloaf Cone Andesite w/quartz veins SP Stat C +1000E M-1)Upper Makushin Valley Altered Rock Near Hg Stat.86M-12 Upper Makushin Valley Altered Graywacke SP Stat.P+200 W M-13 Upper Makushin Valley Plutonic 200m S of Camp M-14 Pass between Fumarole Fields #2 &#3 Altered Ash Hg Stat.106 M-15 Hot Spring Group #9 Argillic Alteration M-16 Fumarole Field #1 Argil'lic Alteration M-17 NOT SAMPLED M-18 Fumarole Field #1 Argillic Alteration. M-19 Plateau above Fumarole Field #3 Glassy Andesite SP Stat.U +2880 M-20 Near Fumarole Field #2 Altered Volcanic .SP Stat.SS+3200 M-21 Fumarole Field #2 Argillic Alteration Nae: M-22 Fumarole Field #2 Argillic Alteration Wy M-23 Fumarole Field #3 Argillic Alteration M-24 Fumarole Field #3 Plutonic M-25 Fumarole Field #3 Argillic Alteration M-26 rumarole Field #3 Sub]imates M-27 Fumarole Field #3 Metacinnabar 1 M-28 Fumarole Field #3 Argillic Alteration MK=17 Upper Glacier Valley Hornfels(?) The southern-most of the three observed faults is visible from the river in west Glacier Valley where it appears as a linear offset of the recent alluvium in the.northeastern 'river bank.The fault appears to strike northwest-southeast with the southern side downthrown.Unfortunately,thick vegetation and lack of surface expression preclude direct fault examination. Hydrothermal alteration areas of varying sizes and intensity surround all of the surface geothermal manifestations;the great majority of these. areas outcrop along a linear zone extending from upper Glacier Valley to the"upper Makushin Valley.The alteration around all of these<fumaroles andspringsappearstoberecent;therefore,it was mapped in de Ail.There also exists a type of alteration that is particularly associated with the linear zone,which is intense,of near-neutral pH,orange in color,pyritic and siliceous.This alteration seems to be associated with an older hydro- thermal event;therefore,it was not studied as carefully as the younger altered zones.7 Hydrothermal alteration studies included detailed mapping of alteredareas,cursory field examination of the alteration.products,sampling of. representative materials,and classification by age,intensity of altera- tion,pH conditions,and alteration type.Selected samples of recent alteration products were shipped to Los Angeles for mineralogic X-ray analysis studies (Table 1). Geothermal manifestations occurring in the Makushin Volcano geothermal prospect consist of fumaroles,hot springs,warm ground,mud pots,mud volcanoes,and hydrothermal alteration zones.Of the 23 manifestations currently identified in the prospect area,8 were known before this inves- tigation (Motyka et alesey)and 15 were 'discovered during the 1982 fieldwork.cone The locations of all 23 of the Makushin Volcano geothermal manifesta- tions were accurately determined and then mapped (Plate I);surface tempera- tures were measured,flow rates estimated,and secondary.geothermal deposits re) noted.This information and the hydrothermal alteration data have been combined in the descriptions of each manifestation which follow.Some fumarole fields and hot springs groups include several areas of geothermal manifestations;these areas have been designated as subgroups in the mapping or written descriptions. Coordinates given for thermal phenomena that are within the area topographically mapped as part of this contract are based on the Alaska ; State Plane Coordinate System.The location of thermal features outside of the topographic map area have been defined by latitude and longitude. iv -Fumarole Field #12Pycgefwre Fumarole Field #1,which is located on the northwestern side of a steepcanyonatapproximatelyN1,181,600 £4,972,700 (Plate I),consists of numerous steam vents situated in a zone of intense hydrothermal alteration that covers approximately 500 square meters and a larger halo of less intense alteration (Figure 1).Within a 10-meter by 20-meter area there-are at least 15 steam vents that emit vapor with surface temperatures between 68°C and 100°C.Venting steam locally forms mud volcanoes and mud pots in marshy depressions."Surface runoff water enters the steam vents at several locations and mixes to form warm rivulets and warm (<21°C)water seeps atlowerelevations.The vents emit a mild odor of H9oS,and the orifices of the vents are lined with sublimated sulfur crystals,sulfates,and abundant disseminated pyrite.The hydrothermal alteration type,as determined by X-ray analyses,is mainly argillic with iron oxide and sulfate minerals fairly abundant.Both kaolinite and montmorillonite clay,which occur in the argillic alteration,indicate an acidic type alteration.The acidic hydrothermal fluids have completely altered both the original rock and young talus deposits,suggesting that intense hydrothermal alteration is continuing. Fumarole Field #2 Fumarole Field #2,the largest thermal area on Makushin Volcano,con- sists of five separate vent groups aligned on a northeast-trending line centered at N1,174,900 £4,968,700 (Figure 2).The vents occur in intense hydrothermal alteration zones that are distributed from elevations of approximately 2,000 feet to 2,400 feet,with the elevation decreasing to the north.The escaping vapor contains some H9S gas and ranges in temperature from 81°C to 99°C.Surface runoff locally mixes with the emitted vapor to form warm creeks and hot-water seeps that flow from several orifices down- slope of the vents.The two hot springs that emerge in Area 2-4 have temperatures of 32°C (water sample M-2)and 96°C,respectively and a com- bined flow rate of about 90 liters per minute. 14 vFIGURE 1 . eae <ay +1,118,600 7 FUMAROLE FIELD #1 E 4,972,700 GROUP Moaff (TRIBUTARY OFMAKUSHINVALLEY RIVER 68°-100°C LEGEND WEAK ALTERATION INTENSE ALTERATION ZONE OF HYDROTHERMAL ALTERATION |ffQmv ZONE OF STEAM VENTS WITH TEMPERATURE OF VENTS HOT SPRINGS GROUP #10 '¥GrooacuNts AM STEAM VENTS OR MUD VOLCANO WAAM WATER SEEPS ANO WARM CREEKE HOT SPRINGS Men:GEOLOGIC SAMPLE |* Quaternery Altuvium Quaternary Till a y Mab Pyr Quaternary Makuthin Voicanies Tartlary Plutonics Miocene Unalaske Fm, hin Py AGI C94S vax FIGURE 2 |FUMAROLE FIELD #2 AND'HOT SPRINGS GROUP #9 i HOT SPRINGS GROUP #9 ED,|"]38° e. |AREA 2-5 /. .Tmu 87 "/&Np 81°-99°C /SCALE - %.'ia 4 0 50 100 mj96°C N 1,174,900|E 4,968,700 Tp LEGEND 'AREA 2-2 ¢:WEAK ALTERATION INTENSE ALTERATION ZONE OF HYDROTHERMAL ALTERATION |i79°-99°C ZONE OF STEAM VENTS WITH TEMPERATURE OF VENTS APPROXIMATE BOUNDARIES OF MAIN GEOLOGIC UNITS -e STEAM VENTS OR MUD VOLCANOY/Y Tp _'ot A WAAM WATER SEEPS ANO WARM CREEKS | Sx)a a HOT SPRINGSoeWyaNAREA2-1 \we ."Pe |Ment GEOLOGIC SAMPLE .Tmuy s Qal Quaternary Alluvium ot /Gt Quaternary TillOmpOoyMekushin Pyrociasti Omy Quaternary Makushin Volcanics Te Tertlary Plutonics : °1 Tmu Miocene Unalaska Fm. Rat C948 |b The hydrothermal alteration zone in Fumarole Field #2 ts recent and ;extends fairly continuously for at least 600 meters in a northeast-southwest C3direction.The alteration is intensely developed in the dioritic rocks,but - is virtually nonexistent in the younger Makushin Volcanics that cap the*diorite.Minerals present'in the alteration consist mostly of kaoliniteclay,quartz,and iron oxides,with locally abundant disseminated pyrite. This acid alteration assemblage is characteristic of vapor-dominated areas. Fumarole Field#3 Fumarole Field #3 consists of three main steam vent areas and one hot spring group separated by weakly to intensely altered bedrock outcrops.| These vents and hot springs are within a crude triangle whose center is at NI,167,200 £4,964,800 (Figure 3).-A.fi rsTheventshavebeenseparatedintothreegroups(Areas 3-¥,3-2,and3-3)according to their location.The main fumarolic area (3-1)consists of numerous steam vents,whose surface temperatures and activity vary widely, scattered in subgroups separated by intensely altered outcrops.The most intense fumarolic activity in Area 3-1 occurs at a series of approximately 10 vents having steam temperatures that range from 99°C to 152°C.The :superheated steam escapes at high velocity from intensely altered,fractured diorite and emits a mild odor of HoS.The outcrop immediately above these steam vents is a 100-meter thick,unaltered,Makushin series andesitic laVa flow,which acts as a cap rock over the superheated steam vents of Area 3-1.The hydrothermal alteration in Area 3-1,whichis recent,appearssimilartothatseenattheotherMakushinVolcanofumarolicareas,andconsistsprincipallyofkaoliniteclay,quartz,orthoclase,sulfides,and sulfates.Sublimates from the steam vents include-native sulfur and iron oxides.The altered rocks between Areas 3-1 and 3-2 contain moderate amounts of a black mineral tentatively identified as metacinnabar. Fumarole Area 3-2 comprises four minor groups of steam vents having surface temperatures that range from 83°C to 98°C.The altered rocks surrounding the vents consist mostly of clay minerals,large amounts of disseminated pyrite and locally abundant iron oxide.Warm creeks,created by the steam mixing with surface water runoff,are stained with iron oxide. A series of hot springs emerge at the base of Area 3-2.These springs have extremely low flow rates,range in temperature from 81°C to 100°C,and 'appear to result from the influx of steam into ponded surface water.They are characterized by an abundance of colorful algae and locally small deposits of calcium carbonate (travertine). Fumarole Area 3-3 was inaccessible at the time of this survey,but it appears to consist of two steam vents emanating from an intensely altered area.The two vents are small in comparison to areas 3-1 and 3-2. 14 >FIGURE 3 ¢N 1,167,200: 15 eS LEGEND -ome aa: ce ")_ZONE OF HYDROTHERMAL ALTERATION WEAK ALTERATION INTENSE ALTERATION ZONE OF STEAM VENTS WITHTEMPERATUREOFVENTS APPROXIMATE BOUNDARIES OF MAINGEOLOGICunrTS STEAM VENTSOR MUD VOLCANQ WARM WATER SEEPS AND WARM CREEKS |9 HOOT SPRINGS M-a GEOLOGIC SAMPLE Gusternary Alluvium Quaternary Til Quaternery Mekushin Pyroctastics OCxcoternary Makushin Volcanics Tertiary Ptutonics Weocene Unelasia Fm.Rot ceas |fl act C313 Fumarole Field#4 Fumarole Field #4 lies about 1.5 kilometers east of Fumarole Field #3 along the west side of a small valley tributary to Glacier Valley (Figure 4).This fumarole field is located at N1,167,050 E4,960,500 within an area of intense hydrothermal alteration.There are two large wet-steam vents,approximately 20 smaller steam vents,and several hot water seeps, all of which are situated on the banks of a moderate size stream that flows south along the base of the steep cliffs which form the west side of the valley.Their surface temperatures range from 71°C to 100°C.Steam and 89°C to 100°C hot water surge periodically from the two largest vents. Total flow from the system ts very difficult to estimate,but it is probablylessthan400litersperminute.The vents extend for 100 meters to 125-meters along the stream bank and emanate froma glacial till that is intensely altered to kaolinite and montmorillonite clays. Bedrock was not visible due to mantling by ti11 and talus deposits, however,it is probable that bedrock is the altered diorite that forms thecliffsontheeastsideofthevalley.7 Fumarole Field #5 Fumarole Field #5,which is located within a minor glacial depression at approximately N1,164,650 £4,955,300,consists of two steam vent areas - (Figure 5).Area 5-1 contains four orifices concentrated in a 7-meter by 15-meter area.The orifices emit 98°C steam at moderate pressures that decrease eastward.Surface runoff enters a few of the steam vents and mixes to form warm water seeps.The steam vents emit a-strong HoS odor,and the orifices of the steam vents have native sulfur crystals deposited around them.Steam at high pressure flows constantly from the single orifice at \Area 5-2.Intermittently,this flow.is interrupted by violent eruptions of boiling water. Both steam vent areas are surrounded by a halo of moderately altered rocks.The alteration within the halo is spotty,with an acid-argillic type predominating.Clays observed within the halo zone are kaolinite and montmorillonite,both of which are tinted by red iron oxides. Fumarole Field #6 This extremely active fumarolic field is located approximately at 53°53'20"N 166°55'00"W in the summit crater of Makushin Volcano and consists of two large solfataric areas that emit a large amount of HoS-rich steam. The main solfatara.is a dome-shaped agglomerate of dark volcanic cinders which have been weakly altered to dark-colored clay minerals.The agglom- erate also contains abundant sublimated sulfur.The steam produced fro numerous vents in this area has a strong H9S odor. 16 ' FUMAROLE FIELD #4 FIGURE4 ee a Corres NN 1,167,050|E 4,960,500 GLACIER AND SNOW FIELD LEGEND rw)PPPapel23WEAK ALTERATION INTENSE ALTERATION ZONE OF MYOROTHERMAL ALTERATION ZONE OF STEAM VENTS WITH TEMPERATURE OF VENTS APPROXIMATE BOUNDARIES OF MAIN GEOLOGIC UNITS : STEAM VENTS OR MUD VOLCANO WARM WATER SEEPS AND WARM CREEKS MOT SPRINGS M=x GEOLOGIC SAMPLE Quaternary Alluvium Quaternary Till Quaternary Makushin Pyrociastics Ousternary Makushin Volcenics Tertiary Ptutonics Miocene Unsiasia Fm. FIGURE 5. PRE ay ne rey seereerenns SRE eer ree rere rena FUMAROLE FIELD #5 |é ms, ._N 1,164,650iaan|64,955,300” Ef 4 VENT AREA 5-2©Fek 98°C LEGEND WEAK ALTERATION INTENSE ALTERATION ZONE OF HYDROTHERMAL ALTERATION ZONE OF STEAM VENTS WITHTempERATUREOFVENTS APPROXIMATE BOUNDARIES OF Main, GEOLOGIC UNITS. STEAM VENTS OR saus0 VOLCANO WARM WATER SEEPS AND WARM CREEKS MOT SPRINGS Mx:GEOLOGIC SAMPLE Quaternary Alluviers Custernary Til Quaternary Makushin Pyroctastics Ou nary hen V :J ve Tertiary Plutonics '- Miocene Unsiaskea Fin. 'Esk C946 The second fumarolic area in the Makushin Volcano crater is revealed byalargecylindricaldepressioninthesnowandicecoverofapproximately50-meters diameter.Steam escapes at high flow rates from the bottom partofthecavity,possibly under superheated conditions,as reported by Maddren(1919).The icy walls are coated with sulfur sublimated from the steam. However,the obviously dangerous terrain conditions did not permit any studyofthisarea. The amount of steam discharge has been reported by Dutch Harbor fresi-dents to vary in a pulsating fashion;however,the flow rate observed duringthissurveyappearedtobefairlyconstantandverylarge. Fumarole Field #7 This fumarole is located on the northern flank of Makushin Volcano,at an elevation of about 2,800 feet,at approximately 53°54'SO"N 166°55'15"W. It consists of an argillaceous-altered area of approximately 500 square meters,and several small vents which intermittently emit steam;however,no steam was being emitted during two separate surveys made in July and August.Although geothermal activity of this area is not particularly intense,the existence of this fumarole suggests that a geothermal reservoir may lie at depth beneath the northern side of Makushin Volcano crater.A peculiar red coloration of the streams in the steep glacial valley northwest of Fumarole Field #7 is due to iron oxides leached from hydrothermallyalteredbedrock.a""' oa f s$Fumarole Field #8 _of ak ped\This small fumarolic field is located at N1,189,200 £4,974,600.on\a fA ridge approximately 500 meters due west of Sugarloaf Cone,at an elevation 4See,of 1,610 feet (Figure 6)..It consists of two active steam vents approxi- mately 10 meters apart that have surface steam temperatures of 78°C and 83°C,and an extinct vent.The emitted steam has a small flow rate,and does not appear to contain high concentrations of HoS in comparison with other,more spectacular fumarolic areas.The hydrothermally altered zone, which appears to be recent,is approximately 30 meters long,surrounds the steam vents,and appears to consist of clays,minor silica,and iron oxide. Bedrock in the area is andesitic lava containing sulfide minerals (chalco- pyrite and pyrite)and silica veins. Hot Springs Group #9 e These hot springs are located downslope from Fumar ote Field #2 and arediscussedwithFumaroleField#2. Hot Springs Group #10 This area,which is located downslope and slightly upstream from Fumarole Field #1,comprises a warm pond,four warm springs,and a large outcrop of hydrothermally altered rock (Figure 1).The springs have surface J 02"©-EXTINCT FUMAROLE VENT 4"1,189,200E4,974,6000 FUMAROLE FIELD #8 10 LEGEND WEAK ALTERATION INTENSE ALTERATION ZONE OF HYDROTHERMAL ALTERATION ZONE OF STEAM VENTS WITH TEMPERATURE OF VENTS APPROXIMATE BOUNDARIES OF MAIN GEOLOGIC UNITS STEAM VENTS OR MUD VOLCANO WARM WATER SEEPS AND WARM CREEKS HOT SPRINGS M-nt GEOLOGIC SAMPLE Quaternary Altuvium Quaternary Till Quaternary Makushin Pyroctastios Quaternary Makushin Volcenics Tertiary Plutonices Miocene Unalaska Fm. RG!C948 | act C936 temperatures of 29°C,45°C,49°C,and 50°C,and an estimated total flow rate of about 35 liters per minute.The hot spring waters have a chloride concentration of 6 milligrams per liter and deposit a thin layer of whitescaleonthesurroundingrocks.Field tests indicate that this precipitateisamorphoussilica.A large outcrop of andesitic tuff,from which the springs emanate,has been intensely altered into sericite,quartz,ortho- clase,and abundant disseminated pyrite. Hot Springs Group #11 At N1,166,000 £4,965,300,a series of hot springs emerge along the eastern Flank of Glacier Valley approximately 75 meters downstream from Fumarole Field #3 (Figure 7).These springs contain a variety "of colorfulalgae,and they are depositing smal]amounts of calcium carbon;e.The"springs have an average flow rate of 17 liters per minute and,a maximumsurfacetemperatureof70°C.yj A pervasively altered outcrop of diorite 1s located approximately 100meterssouthofHotSpringGroup#11.This outcrop is.well fractured and may constitute evidence for the existence of a high angle north-south striking fault. Hot Springs Group #12 - Four major hot springs and several warm water seeps are located approxi- mately 200 meters downstream and across the Glacier Valley river from HotSpringsGroup#11 (Figure 7).The larger orifices produce thermal water at . less than 20 liters per minute and have maximum surface temperatures of 43°C.The vents are completely surrounded by gras$and contain colorful algae and minor travertine deposits. Thermal Area #13 7A This area is located at N1,184,000 £4,975,750 within a recent landslidescarp-on the western flank of Makushin Valley canyon.The 10-meter long area is hydrothermally altered in a style similar to that seen at Fumarole Field #8,and it may be an extinct fumarolic area. Thermal Area #14 This area,located at N1,179,000 E4,971,850,consists of a minor heat flow anomaly that is expressed by anomalous snowmelt on the canyon flank adjacent to the 1982 base camp.This feature is within pyroclastic deposits that mantle diorite bedrock.: Thermal Area #15 This thermal area,located at N1,200,450 £4,976,050 on the Sugar loaf Cone plateau,was detected by a conspicuous absence of snow,possibly due to anomalous heat flow.This 20-meter diameter area does not contain steaming 21 FIGURE 7 HOT SPRINGS GROUPS #11 AND #12ay PYROCLASTICS FUMAROLE FIELD #3EaHOTSPRINGS 70°C *.N 1,164,000sedosd200 Pa ie |g HOT SPRINGS GROUP #11 NH LEGEND WEAK ALTERATION INTENSE ALTERAT#OS ZONE OF HYDROTHERMAL ALTERATION ZONE OF STEAM VENTS WITH TEMPERATURE OF WENTS APPROXIMATE SCAMEDARIES OF MAIN GEOLOGIC UNITS STEAM VENTS OR REID VOLCANG WARM WATER SEEPS AND WARM CREEKSEYRIVERUv HOT SPRINGS M-a:GEOLOGIC SAMPLE Quaternary Alluviurs Quaternary Till Gusternary Mekushin Pyrociastcs Quaternary Makushin Voicanics Tertiery Plutonics - Miocene Unelesia Fen.GRPxapelGLACIERVALLRGIC94S nA *ground,nor 4s the measured ground temperature anomalous,but bedrock has undergone a significant degree of argillaceous and siliceous hydrothermal alteration. Thermal Area #16 - This area is located across the canyon from Thermal Area #17 at N1,181,600 £4,970,700,and consists of a zone approximately 50-meters long and 10-meters wide,oriented in an east-west direction.This area shows anomalous heat flow,as expressed by the absence of snow in patches,and by minor steaming activity.The ground temperature in the snow-free area wasapproximately10°C,while the surrounding ground was frozen. Thermal Area #17 This large area is centered at N1,180,600 £€4,969,800,on the steep southwestern flank of the canyon bordering the "Fox Canyon"plateau.It consists of a large,intensely altered zone seeping minor amounts of steam and HoS.This hydrothermal area could not be reached because it is ona virtual cliff;however,it was studied from Thermal Area #16 and from theridgeimmediatelytotheeast. Hot Springs Group #18 ed Three large hot springs and numerous warm water seeps are located in a canyon off the western side of upper Glacier Valley at N1,164,350£4,962,000.All three springs issue froma grassy knoll approximately 20 feet above the river,and are roughly aligned along the river.Nearly 30 meters separate the downstream spring from the middle spring which is,in turn,about 45 meters from the upstream spring.The flow of water from each spring ranges between 35 and 85 liters per minute with identical surface temperatures of 59°C.Minor deposits of calcite and red iron oxides occur at all three spring orifices. Fumarole Field #19 This previously unreported fumarole field 1s located near N1,164,900 £4,960,000 about 650 meters south-southwest of Fumarole Field #4 in a small tributary valley to Glacier Valley (Figure 8).Its location is about200-meters upstream of the confluence of this small stream and the larger stream that drains the valley and glacier of the Fumarote Field #4.The Fumarole Field #19 area comprises small fumaroles and mud pots that flow from a remnant spur of glacial till about 7 meters to 10 meters above thestream., There are 5 major vents and 6 smaller vents with vapor temperatures between 97°C and 98°C.Most of the vents produce saturated steam and minor amounts of water.Some vents flow steam only,and a few of the larger vents are now mud pots that have nearly dried up.-The active vents trend 23 FIGURE 8 FUMAROLE FIELD #19 XN N 1,164,90042xE4,960,000 LEGEND WEAK ALTERATION INTENSE ALTERATION ZONE OF HYORCTHERMAL ALTERATION ZONE OF STEAM VENTS WITHTEMPERATUREOFVENTS. APPROXIMATE BOUNDARIES OF Mal'. GEOLOGIC UNITS STEAM VENTS OR MUD VOLCANO WARM WATER SEEPS AND WARM CREEKS HOT SPRINGS Ma-n:GEOLOGIC SAMPLE Quaternary Alluvium Quaternary Till Quaternary Mekushin Pyrociarnes Quaternary Makushin Voicania Tertiary Plutonics . Miocene Unslasks Fn. "ML CeSz AatidNaenorthwest-southeast and are spread over an area of about 7 meters by15meters.There 18 also a second area (5 meters by 10 meters)of.hydro-thermal alteration that is located about 10 meters to the south of the primary area.It trends in,the same direction,and appears to be a steamseepthathasrecentlydriedup.The hydrothermally altered ground around both the active and extinct vents is composed of predominantly grey,soft,sticky clays that are probably kaolinite and montmorillonite.Their altera- tion appears to be of a recent,low-pH type.Some of the vents have sulfursublimatesaroundthemandothersareringedbyafine-grained whitesublimate.: % *oyhe an fief ,.[ve =lowhe m fi.114 7s¢hecho .fate "Hot Sprin s Group #20 :an id {|7Gels.aThishotspringsgroupcomprisesthreeareasofhotwaterSeepsandsmallpondslocatedinthewesternpartofGlacierValley.Most of thesewerediscoveredin1982byRomanMotykaoftheAlaskaDivisionofGeological and Geophysical Surveys (DGGS).Each group consists of several warm springswithverylowflowrates,average temperatures of 30°to 40°C,local traver- tine deposits,and minor gas emission.These three springs located at N1,160,500 £4,962,500;N1,158,300 £4,962,700 and at N1,152,150 £4,960,600, have reportedly higher chloride contents than the other 'hot springs on Makushin Volcano.The significance of this is discussed under Stage V.B.4. = Hot Springs Group #21 These newly discovered warm springs are located 600 meters southwest of Fumarole Field #1 and are centered at N1,180,550 £4,971,050 (Plate 1).The group consists of one small spring of approximately 38°C flowing a few liters per minute and several (3-4)smaller seeps at 10°C to 16°C spread over a distance of 150 meters.All the vents issue from talus deposits overlying highly altered diorite slightly above the stream level on the south bank.Steaming ground is exposed several hundred meters above the springs. Hot Springs Group #22 This newly discovered group of warm springs is located at the head of Nateekin Valley,where a series of 4 travertine mounds,approximately"J-meter high and 3-meters wide are distributed near the Nateekin River and on the northern flank of the valley.The mounds are distributed in an area approximately 50-meters long,and locally contain warm (30°C to 35°C) puddles of water,with very small intermittent flow and fairly constant gasemission.An attempt to sample the hot springs did not succeed due to thelimitedflowrate.Since the hot springs have notbeen previously studied,it is sug-gested that further attempts be made to obtain reliable water and gas samples. Fumarole Field #23Thisnewlydiscoveredareaissituatedonthe tupper slopes of the .northern flank of the head of Nateekin River valley,approximately 60 meters above Hot Springs Group #22.The area consists of several fumarolic vents that were not steaming at the time of the survey,but which emitted a fairly (nestrongHoSodor,suggesting that the area is active.The fumaroles are Sar situated near the top of a 100-meter wide alteration zone within dioriticrocks.They may be localized by a nearby flow of Makushin lavas which cap the diorite.The alteration type appears similar to that observed at theoutcropnearFumaroleField#3.Therefore,Fumarole Field #23 may represent a local eastward extension of the geothermal system. B.Geochemistry Aqueous samples from both hot and cold springs were collected and analyzed by Republic staff during the 1982 studies of the Makusiin Volcanogeothermalarea.In addition,field assistance was rendered fo visiting chemists from the DGGS and Dames and Moore.Approximately five man-days of geochemical field work were required to sample the area.Field conditions during the geochemical survey ranged from sunny and dry to cold and snowy. Although a helicopter was utilized,most site examinations still required -hiking across rugged topography. At each site examined,the following field investigation method typically was used:first,the orifices of major springs were located and the effluent surface temperature measured;next,the estimated flow rates and the extent and nature of secondary geothermal deposits were noted and recorded;then,based on all this information (but mainly on the tempera- tures and flow rates),individual major springs were selected for deter- mination of pH and chloride concentration;finally,analysis of this data, incorporated with the previously acquired data,was used to select springs that were sampled for complete laboratory chemical analyses. Numerous measuring and analytical methods exist for each of the field geochemical parameters determined.Republic's experience using many of these methods,combined with the stringent field mobility requirementspeculiartotheMakushin.Volcano work,resulted in the choice of the techniques listed in Table 2 to accurately measure each parameter. |TABLE 2 FoldFIELDGEOCHEMICALMETHODS0,a Parameter -Method _AA a Temperature Taylor satan neadtna.Thermometer pH pHydrion Papers Chloride concentration Argentometric Titration : Eight hot springs groups and three cold springs located on Makushin Volcano were investigated by Republic geochemists.All of our field- measured values agreed with analyses by Motyka et al.(1981).Measured surface temperatures (Table 3)ranged from 7°C at a cold spring to 99°C at Hot Springs Group #3-4.Low chloride concentrations,which ranged from 5.5 to 11.4 milligrams per liter,were determined at all sites except the three southern-most hot springs in Glacier Valley.The pH range was from acid (3.3)to neutral (7.0).The majority of Makushin Volcano thermal waters are,therefore,geochemically characterized in the field as slightly acid; low-chloride waters,while the three southern Glacier Valley thermal waters Fs,ace neutral,chlor ide-rich waters.The cold springs are characterized as .neutral-pH waters i ow ones €-aba Oo {dd ae foreapfh5fagsi-a Ih Jj be Lay}«;ot ie reyac veka oof talc Py uly,Republic geochemists collected nine water samples for complete confirma- tory analysis in the laboratory.In addition,Republic assisted Dames and Moore's chemist in collecting waters from Makushin Valley,Driftwood Bay, and Glacier Valley rivers for complete laboratory analyses.At each selected spring,except Hot Springs Group #20,Republic geochemists collected three samples:°platen [L40-J.Mey,laenaeaeAMScemean, rar io1.A 250-m1 sample 6f 0.45 micron-metliquid for pH,Na,K,(HCO,3 ogy CTF SOq,F »By and Br 'halyses. 2.A 250-mi sample of 0.45 micron-filtered liquid which was acidified with nitric actd to a pH of 2.This sample was analyzed for Ca, Mg,Li,heavy metals,and trace elements.rece TABLE 3 €- GEOCHEMICAL FIELD OBSERVATIONS OF MAKUSHIN VOLCANO GEOTHERMAL MANIFESTATIONS Surface Estimated - Tempera-Flow Rate Chloride Secondary Location ture °C Ipm mg/1 Deposits pH Sample No. Hot Springs #10 29 <10 6.2 45 <10 8.5 6.2 49 <10 8.5 6.2 50 <10 8.5 6.2 M-1 Hot Springs #2 32 10 7.4 5.2 M-2 32 10 7.4 5.2 Hot Springs #3-1 58 <10 7.2 Sulfur 5.3 4-3 29 <10 7.5 Sulfur 5.3 * Hot Springs #3-2 86 <10 9.6 Pyrite 3.3 -__76 10 5.6 3.9 Hot Springs #3-4 99 <10 5.5 Pyrite 3.3 84 <10 6 Pyrite 3.3 Hot Springs #11 70 <10 5.5 Calcite 6.3 M-4 ;48 10 8.6 Calcite 8.6 - Glacier Valley Cold Spring 7 100 9.2 6.6 "M-10 Driftwood Bay x <>Cold Spring 8 200 11.4 7.0 M-1]'GF Makushin Valley Cold Spring 8 40 10.8 6.4 4-12 | Hot Springs #18 59 °20 5.9 Calcite GV-1 59 90 5.9 Calcite GV-2 59 40 7.5 Calcite Hot Springs #20 37 <10 ND Calcite ND SG-1 39 <10 ND Calcite ND PV-1 .ESte.located broad Hg anomalies outlining tthe>geothermal areas. 3.An unfiltered 10-ml sample which was added to 100 mi of deionized water for Si0,analysis. . "¢ a At Hot Springs Group #20,only a 250-m1?grab sample was collected. All samples were stored in sealed,acid-washed polyethylene bottles,which were shipped to Vetter Research,a Los Angeles-based analytical laboratoryhavingextensiveexperienceinthechemicalanalysisofgeothermalfluids.'Detailed chemical analysis worksheets for each sample can r found inAppendixE.doer gis)pps dl thle'Ca)bs he C.Mercury Soil Survey Several workers have illustrated that anomalously high mercury (Hg) concentrations exist in soils that overlie high-temperature geothermalsystems.Matlick and.Buseck (1976)determined the Hg concentrations of"Alhorizon soils ona 1.6 kilometer spacing interval in three geothermal oe-areas in the United States.They concludedthat broad 'Hig anomalies Sta oothethreegeothermalareasandthattheHgsoilgas.survey"could 'success fully be utilized as a|geothermal exploration technique. In 1978,Phelps and Buseck continued evaluation of the Hg soil 'mappingmethodasaregionalindicatorofgeothermalresourcesbySurveyingtwo.additional geothermal areas in the United States.These studies also a ef Pr reedLandressandKlusman(1977)sampled and analyzed both 'Ae and B-horizonsoilsingeothermalareas.Their results again indicated that high Hgconcentrationsoccurinthesoilswithingeothermalareas., Capuano and Bamford (1978)conducted five,closely spaced (100-foot)'mercury-in-soil traverses across the Roosevelt Hot Springs,Utah,Known : Geothermal Resource Area (KGRA).The distribution of their Hg values defined structures controlling fluid flow in the Roosevelt geothermal resource and delineated areas overlying near-surface thermal activity. All of these previous studies convincingly demonstrate that Hg anomalies and geothermal activity coincide.They further suggest that the Hg soil mapping technique can define broad regions having geothermal potential.- bee Matlick and Shiraki (1981)compared soil concentrations of Hg with measured temperature gradients at three high-temperature (>150°C) geothermal fields.In all three study areas,Hg anomalies that exceeded background by a 4:1 ratio were located,with the highest detected ratio approximately 110:1.These Hg anomalies always over lapped the thermalgradientanomalies,with the highest Hg soil concentrations occurring near thehighest measured gradient.a a ce"This 'coincidence 'of Hg soiland "high tenperatuze-gradient anomalies ees elmakestheHgsoil,mapping technique a very useful 'geothermal explorationmethod.Other'advantages 'of this exploration technique,including lowcosts,field portable equipment,and mobility add to the cost effectiveness _of the technique. me - The Hg soil mapping exploration survey takes advantage ¢of the high vapor-pressure of Hg which,at ambient temperatures,allows for its easy volatili-'zation.At elevated temperatures,the Hg vapor pressure increases,allowing ">for additional volatilization of Hg.Volatilized lig 1s extremely mobile andisknowntohavepenetratedatleastseveralhundredmetersofrockoverlyingbasemetaloredeposits(McNerney and Buseck,1975).Mercury in"vapor”form will also migrate through water.Thus,once volatilized near a geo- thermal system,Hg will diffuse through wet or dry overburden above the - reservoir.This migration is enhanced by faults and fractures. an mEUpon reaching the surface,Hg can be captured by adsorption on clay. minerals,reaction with organic materials forming organomercury compounds, and by adsorption by iron and manganese oxides (Fang,1978).The result is that soils overlying geothermal resources are enriched in Hg:- Sampling methods employed in Hg soi]mapping consistof collecting B-horizon soils along a regular grid when possible.Experience hasindicatedthataone-kilometer sampling grid will permit detection anddefinitionofHganomaliesoriginatingfromageothermalsysteminthe most cost-effective way.Sizing the collected soils with an 80-mes stainlesssteelsieveandimmediatelysealingtheminus80-meter fractfon in an airtight glass vial prevent contamination and permit analytical reproduci- bility.The analyses are usually performed as soon as possible to Preservesampleequilibrium.t Of the numerous analytical procedures available to determine the soiT's Hg concentration,the technique most commonly utilized employs a gold film -Hg detector manufactured by the Jerome InstrumentCorporation.”The.Anstru-_ee"mental method is based on the phenomenon that a thin gold film undergoes aoeee1)Significantincrease in:resistance when Hg is absorbed."HeNerney,Buseck,"and Hanson (1972)discuss the analytical theory and operation of the goldfilmHgdetector.a uN E 7 oe .vo He . ":. A mercury soil mapping survey was conducted by Republic at the Makushin Volcano geothermal area between April 30 and May 25,1982.Approximately oe-188 soil samples were collected and analyzed to determine their Hg concen oetrationsatthistime.An additional 42 soiy samples were gathered at”} higher elevations and analyzed later tn the summer .°ONE AB RRA SESSatteSoild "The survey covered "approximately 450,Squarekilometers centered ontheBe Te,summit crater of Makushin Volcano.Air temperatures during the surveyrangedfrom-2°C to 13°C with high winds occurring often and the 'deposition _:of fresh snow nearly daily during”the first month of surveying.-)_ are : All soil samples were collected from the B-1 soil horizon utilizing a standard sampling technique which first requires the selection of a contamination-free site.At the selected site,topsoil was removed until the B-1 soil horizon was exposed.A sample of the B-1?horizon soi4]was:thencollectedandsealedinathickplasticbag.Later the same day,the sample was air-dried at ambient temperatures.The dry sample was sized in an 80-mesh stainless steel sieve with the minus 80-mesh fraction stored ina clean glass bottle sealed with a polyseal cap.. a r weyThecollectedsoilsrangedfrombrownclaystolight-brown "andy silts..The soil type accounting for over 95%of the samples was a dafk chocolate- colored clayey silt.This soil contained both anomalous and background concentrations of'Hg.A comparison of soil]type and Hg values indicated that no correlation was detected between Hg concentrations and soil type. The optimum depth of soil sampling in a Hg soil survey is usually = determined by collecting and analyzing soils from three different soil:horizons {A-3,B-1,C=1),at the same location..These repetitive samplings, interference and the c-1 horizon soils on Makushin Volcano occur at. unreasonable sampling depths (>3 feet).The selection of the B-1 soil horizon as the best sampling interval is consistent with previous studies (Landress and Klusman,1977).ee mo ok,os,:7 The sampling on Makushin Volcano was conducted at two different scales.The initial sampling,which surveyed the main area of geothermal Anterest ©:acre e.,the 'east slope of Makushin Volcano and the Point Kadin Rift),was at_600-meter spacing along traverse lines.The second method consisted of .random spot-sampling,to”FAT1-in unsamp led areas.Naturally,soil sampleswereneithercollectedfrombeneathglaciersandpermanentsnowfields,nor =- from areas of obviously allochthonous material such as alluvial fans,stream beds,etc.The final sampling pattern consists of an asymmetric grid that has a high sampling density in the geothermal resource area and a more "scattered sampling distribution in the secondary areas.Oe 22 waa at Makushin Volcano indicated B-1 to be the proper:"sampling horizon.The-.°©7A-3 $01]hor4zon.contains an organic-rich material which caused analytical ©2 eo All 230 soil samples were analyzed for Hg with a Model 301 Jerome Hg Detector which utilizes the thin gold film technique.This technique employs the linearly proportional increase in resistance upon mercury-gold amalgamation to determine mercury concentrations.The detector is - field-portable and has an absolute sensitivity of less than 1 part per billion (ppb). An analysis starts by placing a measured sample into a quartz test tubethatisentrainedintheanalyticalpath.Heating the sample with a propane 'torch for 30 seconds causes mercury in the soil to vaporize.f he vapor isthenblownacrossathingoldFilm.The gold film adsorbs tKe Hg,causing a resistance change,which is converted by a sensitive DC Wheatstone bridge to voltage,and displayed for concentration determination by utilizing the calibration curve method. . , . The analytical range of the 230 Makushin Volcano soil samples 1s between 8 and greater than 31,450 ppb Hg,with an average |value of ASA ppbRie TRG oss_median value As 600 ppb Hg and the mode As.36ppb.Paosew. ie _="An 'ongoing evaluation of the 'Jerome mercury detector s5 day-to-day ..performance was conducted during the survey.The possible effects of.. changes in temperature,atmospheric pressure,and humidity upon Hg -caer,concentrations were also monitored.This monitoring was accomplished by "yas,repeatedly analyzing a soil sample from a standard reference point..The Hg.concentrations determined in these repeated samples are listed in Table Ae.These data indicate that the detector continued to perform satisfactorilyandthatweatherconditionswereofnegligibleeffectontheHigconcen-cae.,tration observed. Sos square |kilometers.This Ag anomaly has four 'arms?with the northwestern TABLE 4 Cs MERCURY MONITORING AT A STANDARD REFERENCE POINT " Observed Hg Value '(ppb)22,27,20,22,20,20,21,23,.2422,25,24,26,26 , X =23 6 =2.4 r or Plate III illustrates the Hg soil concentrations observed v4 each samplesite.Analyses of the Makushin Volcano Hg data indicated ingt the Hg back- ground is 36 ppb.The contours on Plate III are drawn at three times back- ground (108 ppb),five times background (180 ppb),seven times background (252 ppb),and nine times background (324 ppb). The contours outline six Hg anomalies on Makushin Volcano,with each Hg anomaly exceeding 324 ppb.The largest of the six Hg anomalies is situated _on the eastern portion of Makushin Volcano and covers approximately 50 Auto.& arm,Tadiating from Fumarote Field #6 at the summit”toward Fumarole Field #1"Sna north-south trend..The southwestern arm of the this anomaly iscenteredonFumaroleField#5.Although snow cover limited sampling,this anomaly appears to extend southward at least 3 kilometers.The two eastern arms,°'which trend in a nor theast-southwest direction,are composed of Four.individual Hg anomalies.The three northern anomalies,"Fox Canyon",."Camp",and "Upper Glacier Valley",respectively,include Fumarole Fields .#1,#2,-#3,and #4,in addition to numerous minor hot springs and steam a_seeps.:me Two Hg anomaliesaresituated on the Driftwood Bay plateau.:Both are single-point anomalies which occur in hydrothermally altered soil.Active minor steam seeps at Fumarole Field #8 accompany the Hg anomaly west of Sugarloaf Cone. Three Hg anomalies are located along the edges of Makushin Valley. These anomalies cover 20 square kilometers and a1]exceed 324 ppb Hg.Geothermal manifestations are not known to occur within or nearany of 'thesethreeHganomalies. . = Hg anomalies are known to originate from three types of source,e.g., geothermal activity,metal/mineral deposits,and human contamination.The remoteness and lack of significant human occupation within the survey area eliminates contamination as an origin of any of the six Makushin Volcano Hg anomalies.The remaining processes may produce Hg anomalies Pp MakushinVolcanobecausebothgeothermalactivityandmetal/mineral déposits are known to exist within the survey area. Motyka et al.(1981)defined the location of 8 fumarole fields and 4 hot springs groups.During this current survey at least 15 additional geothermal manifestations were discovered,including a 150°C superheated” fumarole in upper Glacier Valley.Metal/mineral deposits on Unalaska Island2._Anclude gold,zinc,pyrite,and copper (Drewes:'et'al.1961),withgold”oe ."peported to occur 'in upper Makushin Valley.Geological 'mapping during:'nis._a"survey located:copper sulfide and mercury sulfide mineralization.oo Therefore,each mercury anomaly may originate from either geothermal activity or a metal/mineral deposit. The three Hg anomalies in and on the edge of Makushin Valley do not occur near known geothermal activity.They do exist near.known-metal/mineral deposits.Field examination of the geology in MakushinVanleyindicatesthathydrothermal'alteration commonly associated with rmetal/mineral deposits 4s widely present in Makushin Valley.Therefore,ab|"appears that these three anomalies:may not reflect a geothermal,source.a" ” The two single-point Hg anomalies situated on the Driftwood Bay plateau are accompanied by both geothermal activity and metal/mineral deposit indicators.The northern anomaly occurs at an area of hydrothermal altera- tion reflecting metal/mineral deposition and in a snowmelt area.In the southern anomaly,steam actively seeps from hydrothermally altered clay at Fumarole Field #8.At this site,the Republic survey team also discovered rock outcrops containing copper sulfide mineralization.The origin of these anomalies appears to be a combination of both geothermal activity and metal/mineral deposits. )| The large Hg anomaly.situated on the eastern flank of Makushin Volcano is associated with both geothermal activity and metal/mineral deposits. Numerous geothermal manifestation (Motyka et al.1981),including fumaroles©with 150°C surface temperatures,exist throughout the anomaly,”Metals . observed during the survey,within the anomaly,include both fhassive pyrite and metacinnabar deposits.Both of these minerals are commonly formed by geothermal activity and may not reflect metal/mineral deposits.Therefore, this Hg anomaly originates at least partially from geothermal activity. _The Hg soil survey determined that large areas situated on the eastern flanks of Makushin Volcano contain soils with high concentrations of Hg.-These high concentrations suggest that much of _the eastern half of Makushin 7 Yotcano may be an excellent geothermal drilling target.The Hg values and- *anomaly patterns.suggest that the best drilling sites are located within: 1)'The 252 ppb contour of the "Fumarole Field #5"anomaly. 2).The 252 ppb contour of the "Upper Glacier Valley”anomaly. 3)The 180 ppb contour of the "Camp*anomaly. ) 4)The 180 ppb contour of the "Fox Ganyon"anomaly. _.The limited size of the Driftwood Bay valley and Fumarole Field #8 Hganomaliesindicatesthattheymaynothavemajorgeothermalsignificance and wee;Suggests that they do not constitute an ear ly arttiing target...- D.Self-Potential Survey There are many geophysical techniques that are used in geothermal prospecting.They include gravity,magnetic,seismic,and electric methods, and also subcategories of each method."After careful consideration of the applicability of each of these techniques to exploration of the HakushinVolcanogeothermalarea,Republic chose the self-potential method as beingmostcost-effective.:_mo Republic selected Dr.Robert Corwin of Harding-Lawson Associates toconducttheself-potential (S--P)survey.Or.Corwin's survey included acquisition of self-potential field data,interpretation and modeling of the data,and preparation of a report.Findings contained in the Final report,attached as Appendix C,are summarized below. The 1982 S-P survey covered approximately 78 line-kilometers.A modified "fixed-base"procedure was used in the data acquisition.The main.7(3-:modification to "standard methods"consisted of using 34--gage "disposable"7 .wire insulated with "Formvar":varnish instead of 'a,20--gage "retrievable" plastic-coated wire.An additional 'change was the deletion of continuouselectrodedriftandpolarizationmonitoring.These modifications were required to obtain reasonable daily data acquisition rates and did 'not affect data quality.|nn The typical field procedure started by digging through the A-3 soil .horizon until fresh soil was exposed.A Tinker and Rasor Model 6B.-nonpolarizing copper/copper sulfate electrode was placedin the fresh soilwitharotatingmotiontoinsureapositivecontactwiththesoll;This) electrode was connected to one side of a Fluke Model 8020A digital multi-meter with an identicalbasestation electrode connectedto the other side. Voltages and contact resistances were then read with this 10-megachminput impedance multimeter. |os Vine.The smoothed 'values,are calculated by a 5-"point unweighted:running.: Self-potential field data was collected along traverse lines.'Normal ..C station spacing on the lines was 200 meters,with closer recordings in interesting areas and wider readings in a limited number of areas having thick snow cover or hazardous terrain.:8%- Time-varying telluric currents which can affect self-potential readings were continuously monitored by a strip-chart recorder connected across a stationary electrode dipole pair.Maximum observed telluric var tations wereapproximately+12 mV/km with a period of nearly 30 seconds.Sélf-potential'readings taken during these rarely occurring electrical stormgwere obtainedbyobservingforseveralminutesandaveragingseveralsucceésivepeak values.Longer period variations did not occur during this survey. The self-potential survey results are shown on Plate IV.All of the smoothed self-potential values (millivolts)are tied and referenced to an assumed zero potential value at the mouth of Makushin Valley (Point A)except.for the Point Kadin lines which are zeroed at the adjacent shores _mean.ae ue __+.mee ..ct .pop tes we =an a :2B,goer :Y . The contours on Plate IV outline two anomalous areas.One negative anomaly of about -600 mV amplitude is centered 1 kilometer northeast of Sugarloaf Cone.A second negative anomaly,with nearly a -500mV amplitude,occurs in Fox Canyon,3 kilometers southwest of Sugarloaf Cone.In addi- tion,a smajlj amplitude me ipolar anomaly was detected near Point Kadin.Lhs Cop (es Mi dwomal pd fuls #9 gf3Theextentoftheseanomalies1sreasonablywelldefinedbythemeasur--Ving station locations.Cumulative tie-in errors around all the closed Tops,were well under 100 mV,which allows for reproducibility of the.measured .self-potential within one contour interval.Therefore,the anomalies are real and not a mathematical function of data reduction.Interpretation of these anomalies is discussed under Stage V.a Poy''A.AymeYue""1.Petrographic Studies:fs a STAGE V -DATA COMPILATION AND TEMPERATURE GRADIENT HOLE PROGRAM PLANNING A.Geology -i The geologic survey of the Makushin geothermal area was conducted prin- cipally during the exploration stages of the project that preceded the drilling of thermal gradient holes.Geologic data compilation included petrographic studies of thin sections made from representative 1rock samples,X-ray analyses of the alteration products found in geothermal manifestation"areas,and development of a geologic map and cross sections,w ich incorpo- rate geothermal,structural and lithologic information.The "purposesof these geologic studies were to determine the distribution and interrelations of the geologic units,to define structural features controlling the surface expression of the geothermal manifestations,to determine the probable location and extent of the geothermal reservoir,to estimate geologic influences on the geothermal resource,and to predict the lithologies to be _encountered in the temperature gradient holes. . .?-}coe :fase or Lone ast yee toe Dobe vd te eosJoepae04LaeBit:deal ¥Lon ; Eighteen samples of rocks judged to be representative of the four: major Makushin geologic units were collected in the field.Subse- quently,fifteen thin sections made from these samples were examined using a petrographic microscope.The following descriptionsof the 2 major formations are summarized from the thin section studies.Detailed petrographic descriptions can be found in Appendix D-1.;ct _The Unalaska Formation outcropping near Makushin Volcano consists ©primarily of tuffs _and lavas.The petrographically studied samples are"andesitic tuffs and 1lavas having porphyritic and trachytic textures. These rocks consist primarily of plagioclase (labradorite),ortho-and° clinopyroxene phenocrysts,and opaque minerals in a glassy to micro- crystalline groundmass that is locally devitrified.The plagioclase crystals are commonly altered to calcite.Other alteration products products include pyrite,clays (mostly chlorite)and iron oxides. Locally,quartz veins and vug fillings reflect hydrothermal conditions(encrustations)similar,to those seen in and near sulfide ore bodies. PaPlutonicrocksintheMakushingeothermalareawereinitially mapped as small dikes and stocks (Reeder et al.,1981).Mapping by Republic and Alaska Division of Geological and Geophysical Surveys (DGGS)staff in 1982 has shown that these plutonic outcrops are part of a fairly large pluton of predominantly dioritic composition,The plutonwassampledineightplacessoastoobtainreasonable'geographic andstatisticalrepresentation.Study of four thin 'sections 'made from these samples confirms that it 1s a fine-to coarse-grained diorite,with plagioclase (labradorite),and ortho-and clinopyroxene crystals.Minor minerals include hornblende,magnetiteand biotite.Alteration of the Makushin diorite is locally intense and appears to have occurred in at least two discrete episodes.The first stage is probably related tothe emplacement of the 'pluton and resulted in the formation of silica andmetallicsulfideaalterationproducts.The later alteration event © "characterized by pervasive argillic alteration accompanied by Tocattyabundantsulfidemineralizationandsilicification.|- The Makushin Volcanics are a fairly homogeneous series of extrusive rocks that locally overlie the Unalaska Formation and/or plutonic rocks and which can be divided into two age groups.Rocks of the younger stage,which is the only age group that outcrops at the surface within the Makushin geothermal area,are mostly andesitic lavas with local cinder.intercalations.-Six thin sections of representative samples ofthelavaswerepetrographicallystudied.They indicate that the younger oeMakushinVolcanics-'are predominantly porphyritic andesites withplagioclase(labradorite),ortho-and clinopyroxenes comprising the major phenocrysts with an accessory mineral suite containing magnetite and rare olivine crystals.The phenocrysts are within hyaloptitic,pilotaxitic,¢or vitrophyric groundmasses. appears'to be:closely related to present-day geothermal activity,and is ee pron suite.surrounding geothermal "surface manifestationswere 'collected | Quaternary pyroclastic flows are distributed in several areas around Makushin Volcano,but their component units were not routinelymicroscopicallystudiedindetail.Nevertheless,one outcrop of altered pyroclastic rock,approximately 150 meters south of Fumarole Field #1, was sampled and a thin section made."Microscopic examination revealed the rock to be a highly altered,recrystallized tuff,or a lahar,'with intense silicification,sericitization,and abundant sulfide mineralization. | a" Five geologic units which are recognized in the Makushin geothermalareawerenotsampledformicroscopicexaminationsincetheycomprise various types of unconsolidated Sedimentary or cinder deposits,which are easily characterized in the field and whose distribution can readily be mapped on air photographs. 2.X-ray Diffraction Analysis and interpretation of HydrothermalAlterationZonesaeeteh5_'Thirteen.samples'Fepresentative of the hydrothermal”"atteration.Detrs$e me, |during the Field survey 'of May 1982.'The samples were sent 'to SEM/TECLaboratories,Tempe,Arizona,for X-ray diffraction (XRD)analyses andmineralogicaldetermination(Appendix 0-2). -The XRD analytical procedure required pulverization of the 'samplesandcreationofa"spindle"which was:then 'mounted on 'a glass slide and 7subjectedtoadiffractometerscan.To assist in identification of the -diffraction peaks and in estimation.of mineral percentages,'energy.dispersive spectra of all thirteen samples were recorded.rng,oriented diffraction.scans were obtained for selected samples.having -unusual diffraction patterns.These data were "interpreted to 'dentity.and estimate relative concentrations of the minerals present. The results of the XRD analyses are summarized in Table 5.Most of the samples consist of argillic alteration minerals that range in clay content from 10 percent to 80 percent.Alteration minerals surrounding Fumarole Fields #1,#2,and #3 were found to be predominantly kaolinite while montmorillonite,sericite,albite,and chlorite were the primary minerals found at the remaining locations sampled.'The occurrence of pyrophyllite at Fumarole Fields #2 and #3 indicates intense.'high |Ne eeetemperatureaalteration,,since pyrophyLlite,only forms above 100°C.-eyAROTHE,eae atewee,tingtieennee Fee,aL wnat Santen haga "Older"first-stage alteration can apparently be distinguished from the "recent"second-stage alteration in the Makushin geothermal area by the higher percentage of albite in the older alteration products. Additional characteristics of the first-stage alteration seem to be low quartz concentrations and a scarcity of kaolinite. The suite of alteration minerals found at Fumarole Field #8 contains 50 percent chlorite and 10 percent albite plus megascopically _observed iron--copper sulfides.'This suggests that the geochemicalcharacteristicsofFumaroteField#8 are different from those at other _fumaroles and that propylitization,near the outer edge of the-:geothermal field,is in progress. 3.Geologic Summary During the 1982 field season,Republic geologists mapped the||_Vithologies,structures,and hydrothermal alteration of the Makushin.Volcano geothermal area.This information was interpreted so as to weliyntle' -ereeeemeaaenty, 'permit construction of detailed geologic maps,and cross sections.-This | asectionofthereport summarizes the information accumulated dur ing the 7geologicsurveys. The geological data available for analysis included that obtained. by Republic personnel,information resulting from geological and geophysical investigations conducted by DGGS geologists during 1982 MN FROM MAKUSHIN GEOTHERMAL AREA,UNALASKA ISLAND,ALASKA .(See Plate 1 for detail location) CR, }Tutt o-TABLE 5 X-RAY DIFFRACTOMETER ANALYSES OF ALTERED ROCKS A?[s) a2 a ..wm. go :-2 .'8 ,g Pe)2 gy ra n7$fe 8%§$GF ££ge &"none i $¢.9 8 £€£35 8 2 BgGeneralco<x 6 ow e ff &£§2 @B Sample #Location ae ae BQ BR cS nS eS eS)32 Be 32 Fumarole os M-2:Field #8 0 10 "--0-*30 -0 0 10 QO 50 0 0 Makushin aeM-5 'Valley -20 40 >O°"0 0 Q 40 0 0 0 0 Glacier - M-8 Valley 50 5 0 0 0 0 45 0 0 0 0 Makushin M-1]Valley 10 30 0 50 0 0 10 0 0 0 0 Hot Spring...aM-15 Group #9 45 0 10 0 0 5 40 0 0 0 0 Fumarole tf M-16 Field #1 30 0 10 10 0 0 0 0 0 50 0 Fumarole,...a be'M-18 Field #1 5 0 0 30 5 °0 QO 60 0 0 :0 Fumarole a M-21 Field #2 20 0 0 40 0 0 0 30*0 .0 10 Fumarole 1 NY 5M-22 Field #2 35 |0 0.0 0 5 0 60 0 0 _.Fumarole |Sts . M-23 "Field #3 20 0 10.°5 5 Tr.5 55 0 0 0 Fumarole ; M-25 Field #3 20 0 5 -0 ,0 5 0 60 0 0 10 Fumarole 7 M-26 Field #3 30 0 10 10 20 0 10 #10 0 0 10 -Fumarole o ° M-28 Field #3 -10 0::0-°::10:°.--0 °0 0 80 0 0 0 (which have not been formally released,but which were made available through personal communications in the spirit of technical cooperation), =and published reports already listed in the Phase IA Final Report.The discussion in this report will focus on that geologic data directly pertinent to the geothermal resource.Aspects of the regional geology are reported in Reeder (1981)and in Drewes et al.(1961). a.Lithology . , The Makushin Volcano geothermal area and its "enyirons areunderlainbyEarlyMioceneageUnalaskaFormationthathasbeen intruded by Miocene(?)plutonic rocks and by Plio-Pleistocene to Recent volcanic rocks that locally mantle both older |units.The area is1S")transected by faults trending'N-S,E-W,NW-SEEan:-SW?the latter of+ae 'Ne aVY-,which predominates.Na "DM ML Shawm -eo os learn nena ™m BetomeneCopog -ae _The Unalaska Formation observed in the Makushin Volcano areaconsistspredominantlyofinterbeddedvolcanicrocks(andesites and"minor pyroclastics)with subsidiary sedimentary rocks (voleanogentesandstonesand'conglomerates),and other sediments derived from . volcanic products (tuffaceous silts and graywacke). The Unalaska Formation rocks have a regional dip of 10 to 15° ;degrees north-northwest.Their attitudecan be best observed on the northern flank of the Nateekin River valley,where the exposed rocks are predominantly lavas and pyroclastics.Similar strikes and dips canbeobservedinthesouthernpartofGlacierValley,where the outcropssteepty :.consist mainly off graywacke.°--;ew TeThegraywackescontain alteration mineral assemblages |characteristic of greenschist metamorphism (calcite,with intense chloritization).The Unalaska Formation exposed at the surface apparently has not been hydrothermally altered by fluids belonging to the present geothermal systems,though these fluids have commonly C,affectedthe intrusive diorite and the overlying Makushin Volcanics. The Tertiary plutonic rocks were found to have a wider surface 7 distribution than previously reported,and it appears that the discrete a.plutonic rock outcrops are actually the surface expression of a ple - moderately large stock (hereinafter referred to as the Makushin ck} lying at shallow depths beneath the Makushin Volcano geothermal area. Field observations and thin section microscopy suggest that -the various outcrops represent a fairly homogeneous intrusive body of dioritic composition;however,it is possible that the diorite pluton may.be a composite of successive distinct stock intrusions. The dioritic rocks appear to have undergone at least two stages of hydrothermal alteration.The first stage,characterized by copious | deposition of silica and sulfides and by intense argillic alteration, was apparently related to the intrusive event when late-stage hydrothermal fluids intensely altered the crystallized diorite and possibly the adjacent wall rock.The second alteration stage 1s obviously related to the presently active geothermal regime.in which'the hydrothermal Fluids have created argiilic alteration zones.The a"superposition of the 'hydrothermal stages:'can be recognized 'both in thepaeerTbeWateheaegtryeeepose.field andPy X-"ray analyses<SE ies Dt 8)ASE bP SES Diorite outcrops examined show relatively dense (0.3-2.5m)joint "patterns.The continuation of these and other tectonic fractures into the subsurface suggest that this relatively large plutonic body may beanexcellenthostrockforthegeothermalreservoir.- Locally,the Unalaska Formation and the diorite are unconformablyoverlainbythePliocene(?2)to Recent Makushin Volcanics.”Thesevolcanicrocksarebasaltictoandesiticlavas,pyroclastics,and .cinders.The Makushin Volcanics have,in the past,emanated from ,several distinct eruption centers.The fumarolic activity and the high temperatures observed (154°C)the crater of Makushin Volcano. OS a indicate that this is presently the most active eruptive center. oa -\oe (ts eaglesubejwadv/s Although no detailed chronological data exist regarding the various Makushin volcanic units,the volcanics have been tentatively divided into two groups on the geologic maps and cross sections (PlatesII,V,and VI).The first is an older,pre-glaciation groupof rocks . which have been subsequently eroded by glacial activity.The second group is a younger series of volcanics which have been deposited in glacially eroded valleys that transect outcrops of the older Makushin -Volcanics and the diorite intrusive.University of Alaska geoscien- tists and DGGS staff are now conducting detailed geochemical andage-dating analyses which will allow stratigraphi¢™d}fferentiation inmoredetailandwithmoreconfidence.f Locdily,the Makushin Volcanics appear to have relatively low vertical permeability,as evidenced in Fumarole Fields#2 and #3,where . _unaltered and apparently impermeable volcanicscap outcrops of diorite that have been strongly altered by intense hydrothermal action.How- ever,other areas have high vertical permeability as evidenced by the _isothermal.'temperature profile in the.'upper 700 feet of temperatureoegradientholeD-1 (see Stage VII.A.1.).The Makushin Voleanics also-appear to have high horizontal permeability within cinder layers, vesiculated lava flows,lava tunnels,and cooling fractures.The high . horizontal permeability permits widespread areal distribution of meteoric and snowmelt-derived waters.This,coupled with the vertical permeability in some areas,could easily facilitate recharge of the geothermal reservoir. Two other volcanic rock types are exposed in the Makushin area. _They are:1)cinder cones,including Sugar loaf Cone and unnamed cones 7 west of Makushin Volcano near Point Kadin;and 2)pyroclastic flows'that have been'mapped near Fumarole Field #1,in Glacier:Valley,in an-unnamed,northwest-oriented,deeply incised valley on the north side of Makushin Volcano,and in several other locations.Sugar loaf Cone is a Cinder cone which is most certainly the product of recent,post- glaciation volcanism and is still virtually uneroded. Cc ROgreel fae geses Se The pyroclastic deposits near Fumarole Field #1 form an extensive plateau (approximately 2 sq.km.)that 4s underlain by lahars and byterracedeposits'that have been covered by successive accumulations of ash approximately 100-meters thick.The pyroclastic plateau.in Glacier Valley is composed primarily of ash layers.It 4s approximately | 15-meters thick and covers an area approximately 100-meters long and 70-meters wide.The third major pyroclastic plateau is in the northwestern part of the area away from geothermal activity and,- therefore,was not mapped in detail.” The other geologic formations which exist in v,Makushin geothermal area include various deposits createdas a result of past and present glacial activity,Quaternary age alluvial fans,and valley-filling alluvium.These granular materials were examined and mapped in order to identify sources of aggregate,potential road building materials,and land features whose presence could - significantly affect road building plans or drill pad design. .Geologie Structure | The regional structural trends of Unalaska Island were described in the Phase IA Final Report;however,more detailed structural studies were conducted in Phase 1B.The direct observation of geologic structuresin the Makushin geothermal area 1s restricted by the cover of young volcanic rocks,by the widespread snow cover,by predominantly oopoorvisibility.due to rain and fog,and by the limited accessibilityoflargeareas.However,several structural elements have been-recognized dur ing Republic!s geologic field surveys and are considered_to.bear significantly on the evaluation of the geothermal potential ofthearea.The "structural analyses of the Makushin geothermal |area byairphotolineamentstudies(Plates VII and VIII)and the:>'Anterpretation of gravity data (Plate IX)are described in sections covering Stage VII.B.and Stage VII.C.The discussions below are restricted to results of the field surveys.ve a , Although the Phase IA Final Report contained references to the € nor thwest-trending "Point Kadin Rift",it 1s apparent from the presents\Ye)study that the main structural direction is northeast,with less well_§'Sener grr rte e'.ae .NY :developed northwest,north and easterly trends.The importance of the -No \northeast trend is emphasized by the correspondence of the locations ofrerFumaroleFields#1,#2,#3,and #8,with the outcrop of MakushinSVayStock.The existence of this major northeast-striking|structure ises \surther supported by the results of the DGGS gravity survey. {aThenorth-south alignment of Fumarole Field #8,fife centralMy,Makushin crater (Fumarole Field #6),and Fumarole Field #1 similarly t may be due to subsurface faults or to the location of the buried western edge of the diorite pluton. are,Other structures of importance that were identified as a result ofthefieldgeologicsurveysandaerialphotographanalysisincludeanNee"east-west trending structure that seems to pass through or near |at -D Fumarole Fiélds #5,#4,#3,and the fumarolic area in the NateekingeMeRivervalley(Fumarole Field #23),and those other faults PreviouslyEedescribedunderStageIV.: B.Geochemistry lL Chemical Analyses ae , abe 4 ae .The chemical analyses of 47 aqueous samples collected from the Makushin Volcano region are listed in Tables 6 and 7,with detailed . 'chemical worksheets in Appendix E.”The samples represent 31 hot springwatersand16groundwaterscollectedbythreedifferentfieldparties.--ae we,a mieThe31thermalwateranalysesdocumentvaluesfortotaldissolved solids (TDS)ranging from 123 mg/l to 1,770 mg/1.Most of the thermal waters have pH values near neutral,although acidic waters do exist within the fumarolic areas.All of the thermal waters,except those C: we' y\tLocationFum.#2 Fum.#2 Fum,#3 Sample #M2 M-9 M3 Temp (°C)32 84 58 pit (units)5.2 "6 5.3 $102 79 154 203 Fe .06 2.5 V1.7. Ca 23.7 65 .65Mg3.7 13 27.4 Na 14 54 28.7 K 2.5 9.0 5.0 .HCO3 81 ND < -C03 0 0 <1 S04 °-40 344 450 Ci 4.8 <10 6.1 F 1.0 <1 1.1 B <.005 <1.0 +38 Li <.01}02 <.01 Sr 3)od os +08 Mn rae '4.9 Zn 09CollectorMatlickMotykaMatlick wl be os ren ND =Not determined TABLE 6 CHEMICAL ANALYSES OF THERMAL WATERS,MAKUSHIN GEOTHERMAL AREA "UNALASKA ISLAND,ALASKA (Concentrations are mg/1 except where noted) Fum.#3)Fum.#3 -Fum,#3 Fum,#3 «S49 HS #9 HS #10 HS #10 HS #10 HS #10 #8 #9 #10 -#11 -06GS1 M-b M-c M-c M-d DGGS2 97 B2 78..«68.B7.4 =87 57.5 35 67 67 6.4 6.5 4.3 ND 5.5 5.5 5.28 6.8 5.32 §.3 94 125 120 138 ==-«140 140 88 105 '88 88 P|01 ND 02 -=.09 .09 .07 ol .03 .03 11.07 32.1 25.4 258 = .«69.3.69.3 23.3 34 23.1 23.1 4.0 10.6 8.0 9.6 .12.2 12.2 5.5 6.1 8.0 8.0 52 87 62 61:28 28 24 32 13.9 13.9 4.8 |5.7 §.2 -3.3:5.6 5.6 3.2 4.3 3.4 3.4 37 288 60 ND:191 191 ND 190 116 16 0..,0 0 ND 0 0 0 0 0 0 129 95 218 491 155.3 155 25 15 21 21.4 <10 5 6.1 203 5 §7.8 7.9 5 5 14 28 oJ "426 12 12 13 <1]|Pah aR] <5 <5 <.01 <0)2 <5 <5 01 1.0 ©5 <5 <.01 <.01 <01 ©,04.%'<.01 <01 <.01 <.01 <.01 <.01 J 10 ol07.26 2/6018 .28 28 <0 . Motyka Motyka Motyka Motyka.Motyka Motyka Motyka Motyka Motyka Motyka tog :ty : :te yo % HS #10 WS 41)WS #11 M1 #2 M4 50 79 70 6.2 6.4 6.4 39 142 143 01 2]06 42.5 208 160 8.9 7.8 7.17 22.4 81 74.7 3.5 4.8 4.4 183 256 .252 0 07 U 34 476 392 6 7.5 6.5 1.4 224 1.1 <.005 <.01 <.005 <.01 03 <.01 2]<.01 1.4 Matlick Motyka Matlick Location HS #11 Sample #G2 Temp (°C)68 pl (units)NO S102 138 Fe 02 Ca 258 Mg 9.59 Na 61 K 3.2711C03ND C03 .NO $04 491 Cl 2.3 F 26 B Li 04 Sr 1.08 Mn Collector Motyka ND -Not Determined 1 HS #1HSa63*\GI-C 79 77.5 6.4 4.3 142 120 2 ND 208 25.4 7.8 8.0 81 62 4.8 |5.16 511 6 0 0 476 218 7.5 "6.1 224 <.1 203 01 1.1 2 Motyka §Motyka HS #1l OWS #12|DGGS2 #13 82.4 60.5 6.5 6.0 125 145 <,01 4 32.1 243 10.6 10.7 87.2 64 5.7 3.8 288 360 .0 0 95 472 5 5.8 28 <1 <.05 <} <.01 03 26 1.2 MotykaMotyka TABLE 6 (Continued)CHEMICAL ANALYSES OF THERMAL WATERS,MAKUSHIN GEOTHERMAL AREAUNALASKAISLAND,ALASKA(Concentrations are mg/l except where noted) HS #18 #4 41.5 _03 1.4 is #18 GV2 "§9 "yNS ND 160 <,003 241 10.1 64.1 4.36 0 528 1 5al 44 229 01 1.0 NS #18 GV) 59 7.8 135 <.003 246 10.9 61.1 3.93 305 0 516 5.5 47 28 01 1.1 HS #18 5 62.5 US #20 #16 Motyka Matlick Matlick Motyka Motyka hy HS #20 #17 Motyka Motyka Parmentier NS #20 #18 HS #20 HS#20 PY}SGI 39 40 ND mS NO 101 *86.7 2.1 8 191 159 33.2 27.9 194 33) 20.4 33.8 428 498 0 0 372 212 170.436 02 02 3.6 u.3 5 J 1.2 1.4 1.64 1.64 Parmentier at Makushin Makushin Makushin Makushin Location Valley Valley ;Valley ValleySample#MV BC "MV oS BCTemp(°C)4.8 4.4 °°:4,1 5.1 pl (units)6.1 66°.6.7.°°7.4S102|16 13.1 W9"°F 24Fe1.6 12 °,04)06 Ca 6.3 6.5 V2.7 «22.5 Mg 2.0 1.5 -3.2 4.4 Na 4.8 3.8 16 -9.9 K . 55 026 *75 ;t?1.09C03-3.3 2.1...8.5 *;16.5 C03 0 0 .O Fe 0$04 21.7 17.9 25 >§0Cl.2.4 2.2 -13.5 16.5 Fo -..08 05°.08 .,.088BeeTe||See 7 |P|!she 922:Li 410002 410°002003Srrr Collector Peterson Peterson..Peterson Peterson iu Boaw ND -Not determined ces (Concentrations are mg/]except where noted) Makushin Valley Spring 6 TABLE 7 CHEMICAL ANALYSIS OF GROUND WATERS _MAKUSHIN GEOTHERMAL AREA-UNALASKA ISLAND,ALASKA aa .a) Makushin Glacier Glacfer Glacier Valley "Valley Valley ValleySpring«River -;Spring RiverMi20GVM10GRM1BFI74.96.4 (hk 7.2:6.622.8 3.13 J,14.6 20 039-4 44 245 0.0 5.9 42.9.3.0 9 3645 5.7 (149 1.9 8 nD.5 4.7:rae 1.4 38 8 20s 15.2 4 33 ND 0 "<"Ys,0 0 24 w J20°-°<3 29 10.=18°BA?5.6 73 :Pa ie 66 <1 <.005 <2°619 <.005<01 ):'.009:.<01 0/6 oo oy 208 ;88 Matlick Peterson Matlick Motyka s Drift-ODrift-Drift-Orift-Driftwood Glacier wood wood wood wood BayValleyBayBayBayBayValleyRiverRiverRiverRiverRiverStream GV DW DE DRM OW #7 4.9 3.1 9.0 3.8 7.1 3.8 5.7 6.5 6.3 6,4 ND 27.5 Nn 2)4.5 19.3 4.5 3.7 -03 12 -06 .09 06 29 14,5 9.1 2.6 3.0 2.6 3.6 3.9 2.8 5 1.0 05 6.5 7.4 24 2 6.0 z.0 ,88 259 2.58 -06 47 .06 1.4 6.1 13.4 ND 3.9 ND. 0 0 0 0 0 0 83.5 7 5 3 7.5 3.) 6.2 13.5 45 2.6 4.4 2.6 18 -06 .09 <1}-05 Pe|<.10 <.10 44 °<.0) .001 085 <0] 008 .006 .01 rt <.01 ye ' Peterson PetatgonsPeterson Motyka Peterson Motyka Drift- wood Bay Spring Mi 8 I <.01 74 Matlick __foncentrations,'together with the relatively high.temperature (6°C.aboveotherDriftwoodBayriver.waters),suggest strongly,that thermal "water : from Hot Springs Group #20,contain chloride concentrations betow 10 mg/1,significant amounts of bicarbonate and sulfate anions,and varying values of calcium,sodium,and magnesium (although calcium usually| predominates).Hot Springs Group #20 flows chloride-rich waters thatarealsoenrichedinmagnesium,potassium,and boron.Chmpm)-(>SP Rin eabies in uf petfordofvialbyThe16nonthermalwatersamples,whose surface temperatures range from 3.1°C to 9°C,have TDS concentrations between 15 mg/T and 229 - mg/l.These stightly acid-to-neutral waters are exceedingly fresh,withamaximumchloridevalueofonly18mg/1 (disregarding,the"thermattycontaminatedsample#DE).The sulfate anion is usually dominant in these nonthermal waters,with bicarbonate varying from minor to commanding importance. _Sample #DE,collected at the head of the eastern fork of the Driftwood Bay river,represents a mixture of thermal water and ground water.The relatively high chloride (45 mg/1)and potassium (2.6 mg/1) 'exists in Driftwood.Bay valley.This previously unknown occurrence of ' oe ny) thermal water dramatically increases the known areal extent of the Makushin geothermal resource. (u2.0 Classification The 'chemicat classification of thermal waters and gases may define}their origins.Water characteristics "Fingerprint®the waters"_interaction with rock.This interaction permits a qualitative 2 determination of reservoir type.Chloride-rich waters 'commonly occur inliquid-dominated-areas,while sulfate and bicarbonate type waters arecommonlyassociatedwithdrysteamreservoirs. Most chemical species of geothermal waters found in high-temperature areas can be classified under the general headings of: (a)alkali-chloride;(b)acid sulfate;(c)acid-sulfate-chloride:and (d)bicarbonate (Ellis and Mahon,1977).These classifications have successfully been applied to thermal waters jn nonvolcanic as well as volcanic areas and are convenient for use in discussions of the origin of hot spring waters.Examples of various hot water classifications are given in Table 8.°a" TABLE 8 TYPICAL CLASSIFIED THERMAL WATERS Location .Classification .Resource Type Takinoue,Hachimantat,Japan Alkali Chloride.Hot Water Matsukawa,Hachimantai,Japan Acid Sulfate _,Ory Steam-_..Valles Caldera,New-Mexico,U.S.A.--Acid-Sulfate-"ehlor ide os tet Water:->Dixie Valley,Nevada,Y.S.A,1 Bicarbonate _Hot Water...ee ped.Peet Awe:}Nae Ella dateTinta-_the tow BB and chloride values,accompanied by "high sulfate”"and.scar ete ane emer place all Makushin thermal waters,except thermal waters\in southern Glacier Valley (Hot Springs Group #20)and .Sample DE,in the(acid sulfate class.Acid sulfate waters,low inchloridecontent,can result from steam condensation in surface waters.Hydrogen sulfide gas in the steam is subsequently oxidized to sulfate. Acid sulfate waters are usually found in areas where steam rises fromsubsurfacesteamreservoirsandinvolcanicareaswhere,in the:coolingstagesofvolcanism,only carbon dioxide and sulfur.gases remain,in thevaporsrisingthroughtherocks.The constituents 'present "an the watersaremainlyleachedfromtherockssurroundingthesurfacehot”"springs.Their geochemical significance 4s usually minor in 'exploration work because of their generally superficial nature. ".P NS The southern Glacier Valley thermal waters at Hot Springs Group #20 and sample DE from the Driftwood Bay river contain enough chloride to place them -in the alkali chloride class.Alkali chloride waters commonly form in a liquid-dominated geothermal reservoir when a high till pplivalsof &a \.cet fn Liat 3vw£4,f HO),mm Fick AC wee dennywl temperature water reacts with the wall rock.This reaction char eke.S$bows, ges the water with soluble salts and anomalously high concentrations of silica, sulfa fTw© te,boron,and trace elements. The classification study of Makushin thermad waters indicates that |.the hot springs originate from two different sources.The”largest Spourty "lw Mba riod ry N volume of surface thermal waters forms from near-surface/mixing and ground water. Cou!)byt AstDyed.i L aly bret yfaJUlm.ferseG hes hy Lbs Ly Arte ret of steam : Only the thermal waters of Hot Springs Group #20 and Dr if twood Bay river appear to originate in a hot water geothermal reser voir.This evidence implies that both a vapor .zone (steam cap)and . a liquid-dominated geothermal resource exist beneath the Makushin Volca tote a OO a ae tt 3. no geothermal area. Water oa clybl Lin tbh re te.ec?yl (9;Loe,itell ed0.by@Thtdentitityofjoniccomponentsinthermatwatersiscontrolledby)water-rock (hydrothermal)interaction that charges the water with cals.Experiments by Ellis and Mahon (1967)illustrated the ability of hot water to leach chemical constituents from rocks; chemi therefore,knowledge of thermal water composition aids in modeling _\ geothermal systems. ground waters from the Makushin Volcano region. sodium-calcium-magnesium-type waters, Figure 9 is a trilinear plot of cations in both thermal waters and©_This_dtagram indicatesthatboththermalwatersandgroundwatersarepotasstum-def icient=>-...neThesimilarity-between the.lon .C(R [ratUrey dete laeLOPULR chemistry of the ground waters and the thermal waters suggest a common iS l-_-relationship with mixing accounting for the linear trend This mixing Get /ealappearstoaffectboththermalwatersandgroundwaters and it further suggests that a significant portion of the soluble salts in the rivers .oaoftheMakushinVolcanoareaareduetogeothermallyrelatedprocesses. Age .on .3 a vy ay : ;ho -©BIGURE9CATIONRATIOSINWATERS FROM"THE MAKUSHIN GEOTHERMAL AREA,UNALASKA ISLAND,ALASKAdurAROplibln,aYCompostonof.ke definat ws -catty af |,t.-$e af Covaso fhife:ell he TD O\ banter (tern)4 War -i)(ates Noth ws Ca ws oy oil Mr fs ov lihe)2 Me i °anon7AoFof.Sa |->1sSoe,To abd (sen fay,/we N ee Aca ee yo phat es e Ci -POOR THERMAL WATERS |fll trmes,i =GROUND WATERStmendictsMoy|ns %SEA WATER 5 ,nt we $C.-RICH THERMAL WATERSPeesDing$|.watiappv Pt aCoesooecag ACE €967 4.Reservoir Type er Determination or prediction of the reservoir type (dry steam or hot water)is the initial geochemical exploration objective.Chloride is the most critical single constituent in distinguishing hot water from dry steam systems.Common metal chlorides have negligible volatility at temperatures below 400°C and are not soluble in steam.Hot springs associated with known vapor-dominated reservoirs have chloride . concentrations less than 50 mg/1}(White,1970).Examples 'pc lude hotSpringsatMatsukawa,Japan (3 mg/l),and The Geysers,Uni,fed States(1.8 mg/1)."Hydrothermally altered ground and naturally Aow discharge of waters (10-100 Ipm)are also characteristics of dry steam systems., In addition,sulfate concentrations are anomalously high in hot : springs whose waters are derived from vapor-dominated geothermal reservoirs.The sulfate is formed when hydrogen sulfide gas entrained in the dry steam is oxidized near the surface.This sulfide-to-sulfate oxidation provides several free hydronium ions which produce the low pH E3 (high acid)springs commonly associated with dry steam areas.The high sulfate concentrations and the low chloride concentrations result in high sulfate/chloride ratios in dry steam areas;therefore,a high sulfate/chloride ratio is a geochemical indicator of vapor-dominated geothermal reservoirs. Hot water systems can be identified by chloride concentrations exceeding 50 mg/l.The main hot springs related to hot water reservoirs always have higher chloride values than nearby cold springs and ground waters.They also tend to -discharge water high in potassium,sodium,and boron,and low in magnesium;their pH is usually near neutral. Ground waters in the Makushin geothermal area have chloride values ranging from 2.2 mg/l to 45 mg/1 (Table 7),with only one sample exceeding 18 mg/1.Chloride concentrations in thermal waters (Table 6) occur in two groups:chloride-poor (<10 mg/1)and chloride-rich on, (>140 mg/1).The chloride-poor group accounts for all thermal waters a AL:GHSpd SP except Driftwood Bay river and Hot Springs 'Group #20,whoseose Chloridevaluesare142mg/1,164 mg/1,212 mg/l,372 mg/1,and 38282mg/i.>Thesetwochloridegroupssuggestthatatwo-layer geothermal resource existsCamaonceed beneath the Makushin geothermal area.The upper layer,-a steam cap, overlays a liquid-dominated reservoir.This type of double-layer reservoir is known to occur near active volcanoes in Japan and Indonesia (Mahon et al.,1980).afly wry ol gin,d{ a fect cht)be digeyg as an In the chloride-poor waters,sulfate concentrations range between 15 mg/l and 581 mg/1 with sulfate/chloride ratios exceeding 200:1.The chloride-rich thermal watershave sulfate/chlor ide ratios of 0.47:1 and2.3:1.These discrepant Fatiostsupport the existence of a double-layer reservoir system with the te a steam cap and thelowerratioahotwatersystem...y ya tts twrty.Mar Bh veagi 7.|fy fe:5S.Reservoir Temperature {itr AS falc - Geochemistry is useful in predicting minimum.subsurface reservoir.temperatures of 'Miguid-dominated geothermal reservoirs.Experience 'in."developed geothermal fields has shown that several ionic.concentrationsandratiosarécontrolledbytemperature.At present,the commonly used : chemical geothermometer s are S10,,Na/K,Ca/Na/K+(alka)andMacorrectedalkali. Tentative geothermal reservoir equilibrium temperatures have beencalculatedforMakushinthermalwatersandarelistedinTable9. However,several basic conditions have to exist in order to obtain valid temperature estimations (Fournier et al.,1974),and these conditions -cannot be certified when hot water does not escape from the reservoir.Therefore,the chlor ide--poor water samples from the Makushin Volcanogeothermalareathatlacka"deep"hot water component cannot accurately predict subsurface temperatures.The samples fromHot_Springs Group #20etandDriftwoodBayriverarethe.only”"samples that contain a "deep"ho: 7 Se,Te te eee Tad atid 'aa q *. .\:|ww Yue |_tat \.a}|\W ay \we (5.©TABLE 9 a a SAY >\M GrMy!er TENTATIVE RESERVOIR TEMPERATURES (°C)\CALCULATED USING VARIOUS GEQTHERMOMETERS@ MAKUSHIN GEOTHERMAL AREA,UNALASKA ISLAND,ALASKA Amorphous ,Mg-corrected Alkali Location Sample #Quartz Quartz Na/K Alkali Mq/Ca/Na/K Fum.#2 M-2 127 VW 244 46 46 Fum.#2 M-9 163 40 265 63 :63 Fum.#3 M-3 181 57 270 4]41 Fum.#3 #8 130 14 210 19°7)68 Fum.#3 #9 150 29 183 68 Z 68 'Fum.#3 #10°148 26 202 67 i:67 Fum.#3 #11 156 34 169 /15 HS #9 DGGS1 157 35 285 43 43 HS #9 M-b 157 35 285 43 43 HS #10 M-c 127 Rl 243 46 46 HS #10°M-c 140 19 244 50 ; 50 HS #10 M-d 127 1 308 -43 43... HS #10 |DGGS2 127 11 308 43 43 HS #10 |M-1 93 24 259 37 al HS #11 #12 158 36 176 29 29 HS #11 M-4 158 36 176 3]31 HS #11 G-2 -156 34 169 15 15 HS #11 G-3 158 36 176 29 29 HS #11 G1-C 148 26 202 67 67 HS #11 DGGS}.130 14 218 719 68 HS #11 DGGS2 150 29 183 69 69 HS #12 #13 --750 37 176 20°20 HS #18 #14 159 23 182 14 14 HS #18 GV-2 165 43 186 23 23 HS #18 GV-1 155 33 182 20 20 HS #18 #15 182 30 190 22 22 HS #20 #16 137 W 225 76 76 HS #20 #17 141 20 225 78 718 HS #20 #18 139 18 -221 175 66 _HS #20 PV-1 -138 7 221 80 80 HS #20 SG-1 126 10 219 175 "86 aGeothermometers applied to Makushin geothermal area waters cannot accuratelypredictreservoirtemperatures.Please refer to text. i tet 'odgfe(*|beth ¢ap Liwial otat{'qt Tt Ju fret 'cb /*reWwByyheh:Py vbupt Jol:goa)i >al .t {3%vf of o L,}-("haba"ater component.Their chemistry suggests unrealistically low reservoir temperatures because of the intimate mixing-of the reservoir water withpenceRaeNOERNgroundwaters.That is,confirmed by their low surface temperatures and their high magnesium values.= However,there is a geothermometer that can be used in such cases. The "mixing model"allows the calculation of the original hot water's temperature and the fraction of cold water in the thermal spring..Subsurface mixing can occur by two methods.In one case,ascending hot| water from the reservoir mixes with cooler ground watet wi thout losingsteam.In the second case,the mixing occurs after elasking,with steam separation and loss.In both cases,temperature calculations depend upon knowing the temperature and silica concentration of the cold water before mixing,and of the hot spring after mixing.|Also,it is assumed - that the initial silica content of the reservoir water 1s controlled by quartz solubility and that silica was not precipitated before or aftér Me an sera Toohey eat ES wo SEER kick Cav.|"ee Fournier and 'Truesdei)(1974)devised methods to redict reservoir it. °temperatures for both 'mixing cases!-_In the case ee i ltSpringsGroup#20,two equations are solved simultaneously for the 4unknownsubsurfacetemperatureandthemixingratios.The first.equation (1)relates the enthalples of the three waters.In a similarmanner,the second equation (2)compares the silica concentrations |ofthethreewaters.pon NS , : *.wh Lee wet da ron ooo.- ua HO)+Hy (T=X)=Hg Bee AY Be Set)+Sy (1X)=Ssees (2H=Enthatpy (calvg)."rglvsdS$.=$109 Concentration (mg/1)oy)de tfNe=Cold Water 'Vet tee J 'Ny =Hot Water popu ™ Ns =Thermal Spring x =Fraction of Cold Water ga Chun fy Ch Tn GP Tine C Py *.oF -"y4aOFow)Ve.Cf 4 ae)af fede:ches py forkn.ty) .'Utilizing this mixing model for Hot Springs Group #20 wiwaters with a C:.ca Glacier Valley ground water temperature of 7°C and 14 mg/1 §°$105>Valenawe(Tables 6 and 7),the cold water fraction in Hot Springs Group #20 t*7/orm one accounts for 89 percent of the total flow.The calculattons(Suggesty / ty 7d,ts \Ve oN that the "true"reservoir temperature 1F 286°C )So ,a TE byl Urlat 1°.\Ny 6.Isotopic Composition of Fluids (iw CI,_Ly Be red sSAe -, The stable isotope composition of geothermal fluids can be used toestimatesourcesofrecharge,circulation time,temperdturé,and fluidmixingpaths.Since only hydrogen and oxygen stable isotope analysesareavailablefromMakushinthermalwaters,circulation and temperature _ ?cannot be predicted.These isotope values are illustrated in Table ":y"pee4aq yoo, Generally,the Makushin stable isotope samples plot near the meteoric water line (Figure 10)except for the high temperature steam condensate samples.The thermal waters'stable isotopes form a band between D values of -78 and -84.This band appears to be an average of ah the Makushin ground waters,indicating a multi-level recharge system .with both high and low elevation meteoric water components.The cA Flechloride-rich thermal waters have a slight 5 '8o Shift,as can be tab.a expected from the large near-surface mixing that has occurred.A higher eile 3 CSnAEE can be estimated by continuing this shift until it intersects the Fumarole Field #3 steam condensate boiling trend calculated for a el temperature of 150°C (Truesdell and Hulston,1980).Thisyeintersection(implies that the chloride-rich hot springs are a mixture of approximately 10 percent reservoir water and 90 percent ground water,aa yplichevi.ratio confirmed by the mixing model geothermometriccalculations=ued hn fi 3 |ae J an mM ne (wast kG Ate es ban./5/it pu):'J a _je wesStableisotopevaluesfortheFumaroleField#6 steam condensate suggest that the summit fumaroles do not originate from the same reservoir as the other thermal fluids sampled.The isotopes indicate that the steam originates by boiling a water that originated as meteoric precipitation at high elevations on the mountain.The residual water's Oo{sotopes are not observed in the sampled waters. A note on the use of the Si0,mixing the model (pg.59): I found the only way to generate RGI's results was to assume no steam loss and to use 87 ppm SiO,concentration (RGI analysis,table6)for the2 "mixed"water (see attached graph).All DGGS analyses of the Cl-spring waters show Si0,concentrations of 100 ppm or greater.Note that because of the implications for reservoir temperature we take particular care in our Sid, determination.At least two and sometimes three analyses are performed <n separate samples to check consistency of results. If 100 ppm is used for the SiO,concentration in the mixed water,the2 . mixing line does not intersect the quartz solubility curve.Also,because of the steep slope,this particular mixing line is very sensitive to the choice made.for temperature and $10,concentration for the cold water fraction.I2 think it is very misleading for RGI in this instance to present the results of the mixing model analysis without alerting the reader for possible pitfalls and without offering a more detailed explanaticn 'of how the results were "obtained.| The USGS does not ordinarily use geothermometer temperatures predicted by Si0,mixing models,unless a linear trend is shown between either or both spring temperature vs.Cl concentration and §D vs.Cl (USGS Circ.790). Neither of these trends occur in the Glacier Valley Cl-spring waters nor is there an increase in S10,with Cl as would be expected if a 810,-rich deep water were mixing with cold waters. I have taken particular exception to the application of the Si0,mixing2 model because of RGI's repeated use of the results of this analysis in later discussions as an indicator of a subsurface Cl reservoir,its temperature and chemistry. 50 ESTIMATING TEMPERATURE,HOT-WATER COMPONENT IN MIXED WATER ITDOO CATA TTT TT Tt 700 600 500 400 300 SILICA,INMILLIGRAMSPERKILOGRAM200 100 EROSUREAReLsLLeeDISSOLVED'aRrrtrizyirtliyit LiloloulierdilerddLdLipp etrrrathirytby 100 200 -300O..ENTHALPY,IN INTERNATIONAL TABLE»CALORIES PER GRAM FIGURE 1.-Dissolved silica enthalpy graph for determining temperature of a hot-water component mixed with cold”water yielding warm spring water. steam is assumed to have escaped before mixing (point E for 100°Cin fig.4).3.Move horizontally across the diagram parallel totheabscissauntilthemaximumsteam-loss curve, is intersected (point F in fig.4).Point F gives the enthalpy of the hot-water component before the onset of boiling,and point G gives the orig- inal silica content béfore loss of steam occurred. ee07vbgfXe Sample Location Fumarole #6 Fumarole #6 Fumarole #2 Hot Spring #9 Hot Spring #9 Hot Spring #10 Hot Spring #10 Hot Spring #10 Hot Spring #10 Hot Spring #10 TABLE 10 STABLE OXYGEN AND HYDROGEN VALUES FOR WATERS FROM MAKUSHIN VOLCANO GEOTHERMAL AREAUNALASKAISLAND,ALASKA (From Motyka et al.,1983)Le. Type 'Steam condensate Upper Makushin River Fumarole #3 Fumarole #3 Fumarole #3 Fumarole #3 Fumarole #3 ..Fumarole#3)'Fumarole #3”. Fumarole #3. Fumarole #3 0:Fumarole #3 Hot Spring #11 Hot Spring #12 Hot Spring #12 Upper Glacier River Hot Spring #18- Hot Spring #18 Hot Spring #20 Hot Spring #20 Hot Spring #20 Snow melt Thermal water Thermal water Cold stream Thermal water Thermal water Cold stream. Thermal water Cold stream Cold springs Steam condensate Cold stream Thermal water Thermal water Thermal water Cold spring. Snow melt... Cold stream;.Cold stream a Thermal water Thermal water Thermal water Thermal water Cold spring Thermal water Cold stream Thermal water Thermal water Thermal water 61 -10.9 ...18 §**0(0/00)6H{0/00) -13.0 -107 -15.9 121 -11.05 -17 * -11.9 -18 13.0 -89 -12.4 -81 -11.7 -84 -11.9 -82 -12.1 -81 -11.3 -83 -9.65 -67 -10.4 ¢-85 -13.5 °-88.5 -8.9 -10 = 11.6 -80 -11.9 ||-83 -..VM.ATT1B.eee (-16 | 12.0 2).:86.502T4227AQ -12.2 -80 -12.5 -83 -11.7 -82 -11.0 -19 -10.1 =76.5 -11.9 -83 -12.6 -88 -11.1 -80 -11.05 -82 6244(00)FIGURE10 STABLE OXYGEN AND HYDROGEN ISOTOPES IN THERMAL AND NON-THERMAL MAKUSHIN GEOTHERMAL AREA WATERS -65 I -70 \y - -80--o %-| e -85--A _ FUMAROLE #3 -95--- 100 - ¢SQ4 THERMAL WATERS A A*STEAM CONDENSATE -110 be FUMAROLE #6 ©GROUNDWATERS - ©CI THERMAL WATERS a) -120 I l .-17 {eJ 15 13 rr act oven §189(%a0) 7.Gas Chemistry The available chemical analyses of the Makushin geothermal area gases are listed in Table 11.All of these samples were collected and analyzed by Motyka et al.(1983),who also provided the following discussion.. The Makushin geothermal gases are similar to those of other high- temperature systems (Giggenbach,1980)with C0,N,and H of)predominating.A significant amount of Ho is also prekinteparticularlyatFumaroleField#3 where Ho is one to two'percent of the total gas composition.Concentrations of Ho greater than one percent are commonly associated with high temperature geothermal systems. 0-C0.,-H,S-NH,-H -CHTheinvestigationoftheHo27H,g-Ha-CH,gas system (Giggenbach,1980)lead to the observation that in Equation 1; increasing equilibration temperatures favored the right-hand side.. a RE pee Oy 6 20a a y::"ws. The low valuesof CH,,combined with the large concentrations of . we +"2 at ramus snmeass that a nigh temperature exists.|: D'Amore and Panachi (1980)suggested that geothermal gases can.'beutiizedasageothermometertoestimatereservoirtemperatures.oeAlthoughtheirmethodsarenotwidelyacceptedandmustbeusedwith.great caution,a useful indication 'of 'subsurface temperatures can 'be.obtained from their data.The Makushin gas samples suggest reservoirtemperaturesbetween230°C and 297°c (Motyka et.al.,1983)..Analyses of.ansamples.'from the superheated Fumarole Field #3,"which,should provide thebestestimateofsubsurfacetemperature,predicts 297°C. "TABLE 11 CHEMICAL COMPOSITION OF FUMAROLE AND THERMAL SPRING GASES FROMMAKUSHINVOLCANOTHERMALFIELDS,PRELIMINARY RESULTS,MOLE PERCENT (from Motyka et al.,1983) 1a 3c qd 5e 6f gh gi COs 91.68 87.90 86.39 87.11 :94.81 81.20 92.3 87.5]93.9 HoS 2.63 2.65 5.89 *1.55 10.81 0.8 5.53.3.0 Ho 0.24 0.54 0.74 1.80 1.12 1.23 0.58 0.28 --0.72 Chg 0.03 0.002 0.021 0.02 0.006 0.07 nd 0.07 .nd No 5.36 8.8]6.87 9.41 4.04 4.43 3.6 5.64 6.2 Ar 0.07 0.09 0.06 0.11 0.04 02 bd bd 0.04 bd bd 0.42 0.1 0.06 0.6 He (ppm)8.0 5.6 8.1 4.5 3.0 4.25 nd 17.4 ondT(°C)--98 98 78 98 152 98 .96 97 Date Sampled 8/13/80 8/13/80 7/14/81 7/5/81 7/5/81 7/8/82 7/13/82 7/18/82 ©7/14/82 (a)Steam vent,field #1 (b)Steam vent near center of field #2 (c)Steam vent near center of field #2 wi(d)Acid spring at base of field #3 (e)Steam vent below superheated fumarole in field #2 (f)Superheated fumarole near top of field #3 (g)High-pressure fumarole/geyser,field #5 -(h)Steam vent,near active water,Makushin Summit oo (4)Mudpot,fumarole field #9 SSNyS nd-Not determined. bd -Below detection. 1 8.Summary Analyses of the 31 thermal waters and 16 ground waters show a wide range in concentration of major components.The ground waters tend to be of the low-salinity,fresh,slightly acid,calcium-sodium-sulfate-type. The thermal waters are both chloride-poor and chloride-rich.The,nth. 49chloride-poor group,which is typically a/weak”to 'intermediatecacid pH,moderately concentrated,calcium-sulfate-type”water,has surface o temperatures between 32°C and 97°C.The chor ide-"rich waters,having amaximumchloridevalueof(436mg/1,occur in upper Glacier Valley and inDriftwoodBayvalleyandhave'pur face |temperatures between 9°C and 40°C.- .eat ben dpb The thermal waters are also classified into acid sulfate and alkali chloride groups.The acid sulfate class has low chloride (<10 mg/1). concentrations and high sulfate values,which together indicate mixing Pricesofsteamandgroundwater.The alkali chloride class requires ->aidinteractionoffairlyhightemperaturewaterwithwal}rock to account fase iforitschemicaTconstitution.The presence of these two classes"cesuggeststhatbothasteamcapandhotwaterreservoirexistinthe-|Makushin geothermal area.”The segregation of the acid sulfate.group to | elevations above 800 feet above sea level,and the alkali chloride group to levels below the 800-foot elevation,indicates that steam overlies a liquid-dominated reservoir.,- "The chemical components are similar for both Makushin thermal and cold ground waters.They are potass1um-poor (<4 percent of cations) and appear to be a mixture of geothermal fluids and ground waters.Thismixingisseeninboththethermalwaterchemistry,where low 'Surfacetemperatureandhighmagnesiumconcentrationssuggestmixing,and in )_Driftwood Bay valley ground waters,which have anomalously high chloride - values.The occurrence of high chloride water at lower elevations in both upper Glacier Valley and Driftwood Bay valley (indicates that aliquid-dominated geothermal resource probably under Web ihe Makushin geothermal area.The elevation of the observed chloride-rich waters G suggests that the steam-water interface may exist at approximately 800feetabovesealevel.=): Reservoir temperatures cannot be accurately predicted from thermo-equilibrium calculations utvitzing tthethermal waters'chemicalanalysis.In all cases,mixing of the:'pure!geothermal fluid with ground waters results in erroneous subsurface temperature estimates." However,use of mixing models,which utilize enthalpy and silica NYDB}concentrations in both thermal water and ground water,'"prgduce a (pvt temperature:estimate of 294°C for the resource.Stable {sotope mixing prine'" models also suggest a subsurface temperature on this order.Motyka et } -(1983)calculated a maximum reservoir temperature of 297°C utilizing gas ratios from Fumarole Field #3. C.Geophysics -During May 1982,Or.Robert Corwin,of Harding-Lawson Associates,®EIA ."assisted by Republic geologists.and.G.Arce of the:"University of 'Alaska,*conducted.a Self-Potential (S-P)survey "covering 78 line kilometers on the:"flanks of Makushin Volcano.The quality of the data acquired was excellentanditsinterpretationrevealedthreesignificantanomalies:a 600mv-7 negative anomaly centered northeast of Sugarloaf Cone;a "500mV negative ooanomalyoccurringnearFoxCanyon(about 3km southwest of Sugarloaf Cone);and a dipolar anomaly of about +100mV amplitude about 2km east of Point_Kadin on the west flank of Makushin Volcano..Data collection procedures and.anomaly shapes have been discussed previously in the section on Stage Iv.De|Harding-Lawson Associates!final project report is attached as 'Appendix c.ceetowhichthereadershouldreferfora'thorough discussion of thesurvey 'and |oesats:results.Lo,oto ce a oe moa reetyleyunkotSPdomlyeye|tn on,af ohutyve tbeaewins2chaly",bicoss) Oey oe ams weld a oie:MEaLfSeveeTheoretically,self-potential anomalies can be generated by cultural features,significant soil property variations,conductive mineral deposits, streaming potentials,and 'thermo-electric activity (heat flow).-Thestreamingpotentialmaybecausedbygeothermal]fluids or by cool groundwater. In the vicinity of Makushin Volcano,cultural features and soil property variations can be ruled-out as factors contributing to the observed S-P aanomalies.The survey area is ina pristine,undeveloped state,and 4s:'unaffected by cultural features of any kind.Laboratory ekperYmentsindicatethatthemaximumeffectofsoilvariationsonS-P réadings are on the order of a few tens of millivolts,.far less than the magnitude of the observed anomalies.Additionally,field experimentation showed that S-P readings at Makushin Volcano do not change measurably as a function of soil-type changes. Experience has shown that deposits of electrically conductive mineralsBaecangeneratenegativepolarity.self-'potential anomalies that.are centered"close”to the geometric center.of the deposit.Thé,wavelength and "shape of:;Such anomalies depend on the size,geometry,and subsurface depth of the oe'deposit.-Se The amplitudes,shapes,polarities,and wavelengths of the Sugarloaf Cone and Fox Canyon anomalies are similar to those commonly associated with:oemetallicsulfidedeposits.However,there is evidence that tends to argue :against the possibility that these anomalies are caused by conductive”anmineral'sources:oe oe en 1. Self-potential anomalies were not recorded in several Jocat tons onMakushinVolcanoatwhichabundantpyriteisknowntobe. disseminated;_ 2.The anaerobic,stagnant,reducing environment that is required to generate self-potential anomalies over mineral deposits does not exist near the surface on Makushin Volcano;and 3.Both the Sugarloaf Cone and Fox Canyon anomaly areas are underlain by at least several hundred meters of Recent lava flows in which, to date,there have been no indications of sulfide concentrations. Large self-potential anomalies have been recorded in areas having Significant topographic relief.These anomalies appear to be generated by "streaming potentials"caused by the downward flow of cool,near-surface water.Such anomalies typically become more negative with increasing a"elevation.Plots of self-potential versus elevation show 'that readingscomprisingthethreeS-P anomalies observed on Makushin Volcano do notcorrelate"normally"with topographic conditions.On the contrary,S-P . readings taken below elevations of 1,000 feet (where positive readings might be expected)were consistently in the -0.25 mV range (a condition characteristic of higher elevations).This observation seems to rule out topography as a contributing factor in the genesis of the Sugarloaf Cone andFoxCanyonanomalies. Geothermal resources which are characterized _by high temperature,JargeFluidflows,and geochemical 'conditions that strongly contrast with thesurroundingenvironmentcanalsogenerateself-potential anomalies.The mechanisms that generate these electric current flows are called thermoelectric and electrokinetic coupling.These couplings produce a current flow where 1)either heat or fluid flow is added or subtracted from a point in a uniform earth,or 2)a flow of heat or fluid impinges upon. different geologic environments.Both of these mechanisms can be modeled_by computer to allow estimation of the depth to,and the extent of,the geothermal resource.; IN A preliminary analysis of a geothermal source mechanism for S-P'anomalies detected on Makushin Volcano suggests a model in which a pair of v4 " northwest-trending faults might serve as conduits for bringing geothermal fluids into the region between the Sugarloaf Cone and Fox-Canyon anomalies. However,this computer model requires unreasonably large resistivity 'contrasts between the fault blocks and a very large electrical potentialfrondchaviv.eas-L See Nw?CC along the two faults.Actually,the implied magnitudes of the source plane potentials (2,000 mV to 8,000 mV)far exceed theoretical maxima.In view of ..-the information discussed above,it 4s unlikely that this postulated model for Sugarloaf Cone and Fox Canyon anomalies is correct. | Geothermal self-potential models using one-and two-dimensional sources located beneath the Fox Canyon anomaly predict that the source depth lies between 0.3 kilometers and 0.5 kilometers (980 feet to 1,640 feet).Similar interpretations of the Sugarloaf Cone anomaly estimate an average sourcedepthof0.3 kilometers.Such simple,single-point source 'nodes seem to be supportable. The small,multipolar Point Kadin anomaly could be generated by geothermal activity along a pair of faults that bracket:the recent explosion craters with depth to the faults of 100 meters or less.However,the self-potential data do not suggest that a major resource exists at Point Kadin.we .a .Be a”-eeaecat Soman ao :eat.: iad :Based on the.self-potential data and computer"generated models,both the =."Fox Canyon and Sugarloaf,Cone anomalies seem to be discrete geothermalmydrillingtargets.The geothermal model developed for the Fox Canyon anomalyhasbeenverifiedbydatafromtemperaturegradienthole0-1 (see Stage VII.A.1.);it would seem prudent to drill the smaller Sugarloaf Cone anomalyinthefuture.*.=)fa FP dasate al y of CaM sid fp ,fefel fuente,"hy \/'D.Refined Geothermal Resource Model I "The geothermal model as described in the Phase IA Final Report 4was |modified and refined by.Antegrating and interpreting all newly acquired as _geological,geochemical,-and geophysical data.The revised model was then .. utilized to determine opt imum thermal gradient hole drilling sites.oa The field exploration surveys conducted on Unalaska confirmed the -.existence of a significant geothermal system with surface manifestations """that include fumaroles,hot springs,anomalous heat flow areas,mud pots, and abundant exposures of hydrothermally altered rocks.Fumaroles which 'Soccurintensites.have surface temperatures ranging from slightly below boiling to a superheated temperature of 152°C.Thermal waters extst at ten hot springs locations within the Makushin geothermal area. The surface , temperatures of these hot springs are between 27°C and 100°C,and secondary chemical deposits include sulfur,silica,calcium carbonate,and pyrite. Hydrothermally altered areas of varying sizes and intensity surround the geothermal manifestations and are also found along a linear zone that _- extends from upper Glacier Valley to upper Makushin Valley.Alteration in.the linear zone is of an orange-colored,kaolinitic,pyrttic,”albitic typethatappearstoberepresentativeofanolderhydrothermalfystem.Argillic 'alteration predominates around the manifestations and is occurring at present.This argillic alteration is characterized by formation of kaolinite,montmorillonite,albite,chlorite,and pyrophyllite (a : high-temperature clay). The Makushin geothermal area is underlain by early Miocene Unalaska |Formation that has béen intruded by Miocene Plutonic rocks.Pleistocene 'to"Recent volcanic rocks mantle both older units.'The Unalaska Formation oeobservedintheMakushingeothermalareaconsistspredominantlyof: interbedded volcanic rocks and sedimentary rocks.The plutonic rocks appear to form a fairly homogeneous stock of dioritic composition.The overlying volcanics include andesitic lavas,pyroclastics,and cinders.The more recent volcanics,which include cinder cones and large pyroclastic flows, are of post-glacial age.This recent volcanism is the surface expression of an underlying magma source which appears to be the heat source for the;Makushin geothermal resource.|| A large percentage of the geothermal manifestations occurs within the diorite.The reservoir rock for the Makushin geothermal system appears to be fractured Makushin diorite.The diorite contains both.ts,which tectonic fractures which areoccurona0.3-meter to 2.5-meter pattern,antrendingpredominantlynortheasttosouthwest -ja this fd CGet-fades ro), not \Ve Led lly'.a ;(07 °fo f ratQP-estimate that the steam's fmaxtmum temperature As 297°Ce:eswae Chemical analysis of Makushin thermal waters indicate two water types exist.The predominant type is near-neutral to acidic,chloride-poor (S10 mg/1)water that contains significant amountsof sulfate and carbonate with varying values of calcium,sodium,and magnesium,although calcium usually> predominates.The second type is a chloride-rich water that is enriched inMagnesium,potassium,and boron. Makushin ground waters are fresh waters whose chloride concentration,Aslessthan18milligramsperliter.The calcium and sulfate ions.usually'dominate.The ground waters in eastern Driftwood Bay valléy dre apparently a mixture of normal ground waters and the chloride-rich thermal waters. The chloride-poor thermal waters,which are classified as acid sulfate, obtain their thermal energy from steam and conductive heat flow.The low . chloride values indicate that only steam accompanied by hot gases arepresent,and that a reservoir water,{Vs "Teeking.The steam has migrated fromasteamcapthatalsosuppliesthetenfumaroles._Gas geothermometers ie ak few etLee.wes Tae eo ne a we Fae 34:wore ewer %-ae a "The chlor ide-rich waters occurring in both Glacter Valley and Driftwood ieBayvalleysuggestthataliquid-dominated geothermal resource exists. beneath the steam cap.The magnesium concentrations,stable isotope values, and surface temperatureCindicate)the reservoir water has mixed with groundwatersinthesehotsprings.Mixing model geothermometers predict a .subsurface temperature of (294°C.SStable isotopes of Makushin waters plotnearthemeteoricwaterTine,except for the high temperature steam:necondensatesamples.The chlor ide-rich.water has a slight go shift._that aam"Suggests |"nearly the same."subsurface temperature as the mixing model :*<8"-ee ° a geotneFnoneter The mercury concentrations of the Makushin geothermal area soils are© anomalous in six broad areas.The large mercury concentrations (>31 ppm) indicate that exceedingly high temperatures exist in the subsurface,and that the rock 1s moderately to highly fractured.Self-potential _.boiling and produce--Steam.The steam rises to the surface where it.escapes.er asinintenselyalteredzonesandlocallymixeswith:'surface ground water to - measurements outline three significant anomalies anda minor low trough CwhichextendsfromupperGlacierValleytoFumaroleField#1.Modeling indicates that.geothermal fluid or heat flow produces these anomalies... Point source models predict that the source that lies between 300 and 500 meters below the surface. All of these findings have been integrated into the geothermal Model I (Figure 11),which is a schematic east-west cross section of the Makushin geothermal area.The geothermal fluids originate via precipitation on'recharge areas that are underlain primarily by rocks of the'usa laskaFormationandtheMakushinVolcanics.The meteoric waters pércolate downwards into the diorite and are heated by conduction from a magma at depth to temperatures over 200°C.These hot hydrothermal waters then alter their host rocks at depth and rock-water interaction charge the water with ° dissolved salts.Minor flows of the hydrothermal waters rise to the surface where either they undergo mixing or cooling with meteoric water to form several dilute hot springs or reach temperature and pressure conditions of form several acid hot springs..The high temperatures in the geothermal yN system cause the mercury to rise to the surface,creating high mercury concentrations in soils,while the heat and the circulation of high temperature fluids create self-potential anomalies. - nn sh ve Did .Fumarole Fields #3,#2,#1,and #8 appears to be a large,tectonically fractured zone that has been fractured at least two different times.The 'First fracturing accompanied the older alteration type with the second mot rupturing controlling the present Makushin geothermal system.An "east-westfracturewhichintersectsthelargenortheast-southwest linear in:'upperGlacierValleyappearstocontrolthelocationofFumaroleFields#4,#5,and #23. 3OUNOS LVaH" w CLSEAWAY«*WANpeNIZLI2 LANL GAy\ NOLN1 DLLIWOIG Ej BOINVOIOA NiHSNXWW b ] s3uluoved -y” NOH VUsIIVIVWHEHLOLOAH ONIVdSs JOH a OuvANS apuviowv owonW IE AN3IWIAON ONT WwWuaHLOWdAH a eal ie)CANRAN Es\ NOLLVIUOS VxSYTWNN VaYUV TVWYAHLOADS NIHSNAIVW AHL dO |TAGOW 91ID01049 GINIS3Y | LL AYNDIA t The major geothermal target is the northeast-southwest linear zone, Surface manifestations,hydrothermal alteration minerals,soil mercury concentrations,and diorite reservoir rock coinciding with the zone suggestthatanactive,high temperature (>150°C),liquid-dominated geothermal system occurs at relatively shallow depths. -£.Temperature Gradient Hole Site Selection The integration of the data obtained from the geological,geophysical-and geochemical surveys resulted in development of a refined othermal model.This model was evaluated to outline areas having maxifnum potential for hosting high temperature geothermal fluids.This evaluation resulted in ° the selection of three primary and three alternate drilling sites for temperature gradient holes (Plate VII).The six sites were themprioritized in accordance with terrain,weather,logistics,and environmental parameters.The six sites selected were Sites A,0,E,I,H,and L.These site designations reflect the identification letter assigned on the5application|for the U.S.Fish andWildlife Service Special,Use Permit(see aaAppendixM,Phase IA Final Report).Oe Bs te PS The D site was-selected because of the close correspondence of both | geophysical and geochemical (soil mercury)anomalies in Fox Canyon and | . because of its location close to the postulated heat source.Jhis site also offered the possibility of testing the characteristicsof the Makushin volcanic rocks and of determining the thickness of the volcanics and the_hature of the underlying rock.This site initially had no unusually.adverselogisticalorenvironmentalproblems.Later in the project,strong winds-and fog made logistics less favorable.-me,: The site locatedatthe western edge of the pyroclastic plateau supporting the base camp,site E,was selected to test the area in which a geothermal mercury anomaly and the northeast-trending alignment of 7 geothermal surface manifestations overlap.This site was logistically 74 FEEDODpyroclastic plateau,site E,was preferred because of better access {bility practical and also permitted the evaluation of plutonic rockcharacteristics.It had no unusual environmental problems,and logisticallywastheleasttroublesome: ra Drill site I,located on the small pyroclastic plateau in upper Glacier Valley,was selected as a terrain-and logistical-compromise sitetotest an area that had high soil mercury concentrations,was in proximity to strong geothermal surface manifestations,and was an extension of the a northeast-trending alignment of surface manifestations in uepsr GlacierValley.This site was the most logistically practical for this:area,and itwasthoughttobecloseenoughtotheobviousgeothermalsurface : manifestations to provide information regarding the system boundaries.No significant environmental constraints were detected for this site. An alternate gradient hole site adjacent to Sugarloaf Cone,site A,was selected in order to evaluate the geothermal significance of Fumarole Field #8 and the large negative self-potential anomaly centered near Sugar loaf.”nto)"7 Gone.This.site was considered to have lower priority than the three °.-"primary sites because no significant mercury anomaly was located near"the"".Sugarloaf Cone and the geothermal activity appeared to 'be relatively |restricted. The alternate gradient hole site located between the pyroclastic ("Camp")plateau and Fumarole Field #2,site L,was selected on the basis of its location within the high mercury geochemical anomaly,its high degree of hydrothermal alteration,and its situation along the northeast-trending alignment of geothermal manifestations.The primary site located on the _. and closer proximity to drilling water. A third alternate gradient hole site,site H,was selected below- Fumarole Field #3 in Glacier Valley on the basis of the high mercury geochemical anomaly,the abundant alteration of outcrops,and because of its _proximity to superheated fumarolic activity..The second priority assigned to this site was based on its poor accessibility and the higher potential of |Gx incurring an uncontrolled blowout because of the highly altered nature of . the ground.Also,site I was considered to be more likely to define the southern boundary of the system,especially in view of the existence of hot springs in the southern part of Glacier Valley. F.Temperature Gradient Hole Drilling Program Under "normal"operating conditions in the "Lower 48*,a+500--foottemperaturegradientholesareusuallydrilledusinginteriedjate-sized,rotary,water-well drilling equipment with rock bits,and either air or mud as the circulating medium.Typical completions have 7-inch casing cemented in an 8-3/4-inch hole to 150+feet and 2-3/8-inch tubing then cemented ina. 6-1/4-inch hole to 1,500+feet.However,on Unalaska the following two conditions dictated that this approach would be totally impractical from both economic and operational standpoints:7 -a.It wasanticipated that,both *hard*rock and highly unconsolidated -rock would be encountered,resulting in extremely low penetrationratesorearly.'suspension of the drilling; 2.Terrain and weather constraints were such that even though anticipated drill sites were only 10 miles to 15 miles from Dutch Harbor,camp facilities would be required,and out of necessity the rig,equipment,supplies,and personnel would be transportedand Supported solely by helicopter. | Based”'on 'these 'conditions,and in view.of available funding,the ©decision was made to drill the temperature gradient holes with a small,|portable rig capable of penetrating to 1,500-foot depth using relatively light equipment.Consequently,the generalized drilling procedure described in Appendix F was geared to the utilization of diamond core drilling equipment common to hard rock mining exploratory operations.C) igor” wre te ie) Na G.Permit Approvals Permitting requirements'were discussed in detail in the Phase 1A FinalReport(Task 3,page 11-19).Because of permitting time requirements,approvals for several permits for the temperature gradient hole operations had not been obtained at the time of the completion of the Phase 1A report. Permit applications and approvals which had been submitted or obtained at that time were discussed in Task 5,Subtask B (pages 58-59)and were included as Appendices I-M of the Phase IA Report.4 ° ;aAThepermitapplicationssubmittedandthepermitapprovals received after the Phase 1A Report was completed are included as Appendix G of this report.They are: G-1)Approved Special Use Permit No.AI-82-10,signed by the U.S.Fish and Wildlife Service on April 27,19823.;- .G-2),Solid Waste Permit No.8221-BA002,approved by the Alaska,"Department of Environmental Conservattén on April 29,1982; nr,:PZ sore Re .Soop hee pee .OO gstLteoe-oo ad le r wie,eT 2 eM art res a ae -toe DAT daeG-3)Biological Sampling Permit No.82-87,approved by the Alaska Department of Fish and Game on April 27,1982;- G-4)Temporary Water Use Application,submitted to.the Maska © .Department of Natural Resources on May 6,1982;-aa G-5)Temporary Water.Use.Permit No.82-12,approved by the Maska -Department of.Natural Resources on May 17,1982;::faptentie | G-6)Letter from the Alaska Department of vstural Resources regarding "approval of temperature gradient hole operations,signed by David Hedderly-Smith and dated May 4,1982;es G-7) G-8) G-93) G-10) G-11) 6-12) 6-13). 6-14) G-15) G-16) Geothermal Drilling Authorization,issued by the Alaska DepartmentofNaturalResourcesonMay27,1982;_ Application for Permit for Food Service Operation,submitted to the Alaska Department of Environmental Conservation on May 6,1982; Eating and Drinking Establishment Permit,issued by the Alaska Department of Environmental Conservation on May 17,1982;'BeApplication for a Habitat Protection Permit,submitted to theAlaskaDepartmentofFishandGameonMay11,1987; Letter from the Alaska Department of Fish and Game stating that no Habitat Protection Permit is necessary,dated June 3,1982; Letter to Alaska Department of Fish and Game regarding modifica- tion in the scope of exploration activities and a brief status report of"initial |baseline data collection.fieldI works "<<eelautee):aeReportoftelephoneconversationbetiecnAAlaska=pesartment of Fish - and GameandDames and Moore stating no Habitat Protection Permit is necessary for modified project; Diagram of water system for base camp,submitted to the Alaska Department of Environmental Conservation on June 25,1982; Drinking Water Analysis Report for Inorganic,Organic and Radio- chemical Contaminants,submitted to the Alaska Department of. Environmental Conservation;. - "28 Class C Water and Waste Systems Construction and Operation. Certificate,approved by the Alaska Department of Environmental Conservation; 72 G-17)Cultural resources clearance statement,issued by the Alaska-Department of Natural Resources,Division of Parks,State HistoricPreservationOfficer,on May 27,1982; s G-18)Letter to the U.S.Fish and Wildlife Service regarding cultural resource potential,submitted May 25,1982; G-19)Cultural resources clearance statement,issued by U.S.Fish and-Wildlife Service on June 8,1982.g Some permits had conditions which required correspondence with the agency during the course of operationsor notification of the agency after field work was completed.Letters written to comply with such permitconditionsareincludedasAppendixHofthisreport.They are: H-1)Letter to the U.S.Fish and Wildlife Service in compliance with Special Use Permit;AT-82-08,dated Apri)23,1982; |H-2)-Letter to the U.S.Fash and Wide Service in canpltancettn'ae_Special Use Permit AI-82-10,dated May'25;1982;aaate H-3)Letter to the U.S.Fish and Wildlife Service in compliance with | Special Use Permit AI-82-10,dated August 20,1982;; H-4)Letter to the U.S.Fish and Wildlife Service in compl tance withSpecialUsePermitsAI-82-09 and Al-82-10,dateda September 23,1982;a H-5)Letter to the Alaska Department of Natural Resources An compliancewithGeothermalDrillingAuthorization,'dated September:j23,1982;H-6)Letter to the Alaska Department of Fish and Game in simp tance: with Biological Sampling Permit 82-87,dated December 8,1982. 7a H.Drilling Program Logistics -;Es _.The four major cost items in the drtiing portion of the project were bid on a competitive basis.The following Alaskan firms were chosen as the successful bidders based on economic evaluation: a)Helicopter support -ERA Helicopter,Inc. b)Drilling equipment and personnel -Fxploration Equipment andSupplyCo.(EXSCO)of c)Camp facilities and operation -Production Services,Inc.(PSI)- d)Radto communications system -Trident Communications ° 1.Helicopter Support ..Helicopter Support of the field geology and environmental parties & |was begun in early April using an A-Star-350 that.subsequently was used antosupportthedrillingoperation.Personnel required for helicopter operations were a pilot and a full-time mechanic.Load-carrying capacity of the A-Star is 1,400+pounds on a sling,or five passengers plus the pilot.Fuel consumption was approximately 30 gallons of "Jet A"per hour.Fuel was purchased from Reeve Aleutian Airways,Inc.in Dutch Harbor.Exclusive of rig and camp mobilization and demobilization operations,the helicopter flew an average of approximately 4-1/2 hours per day.Activities were primarily the transportation of rig and camp fuel,drilling equipment and supplies,and camp suppTies.ThehelicopterenabledcrewchangestobemadetwicedailyattemperaturegradientholesitesDandI,barring weather which prohibited flying (site E could be reached by foot from camp).Additionally,two complete rig moves were accomplished by helicopter.Each move required five days from the time of completion of one hole to spudding of the next. 2.ODritling Equipment and Personnel Due to the remoteness of Unalaska Island relative to drilling. services and supply sources,it was decided that all equipment and materials required for the entire three-well program would be transported to a Dutch Harbor staging area and stored -until actuallyrequiredonsite. In early April 1982,meetings were held with EXSCO me agenent toquantify,as accurately as possible,the requirements for/th e projectincludingalldrillingequipmentwithback-up spare parts,tubular goods,blowout prevention equipment,bits and coring equipment,mud supplies,water supply pumps and lines,welding equipment and supplies, etc.At all times it was necessary to remember that no single equipment - item could weigh in excess of 1,400 pounds due to helicopter load capacity limitations.> "Approximatély 32 tons of material were shipped by barge fromAnchoragetoDutchHarbor'in mid-May.°Near the end of May 1982,"'the ."equipment and supplies were unloaded from the Sea Land Services,'Ltd.containers at the Unalaska staging area located at Carl's Inc.Timbers were obtained locally and set at drill site D in order to elevate the rig approximately 5 feet above ground level so as to provide clearance for the blowout prevention equipment.oe .Beginning May 28,drilling equipment was lifted from the stagingareatothedrillsiteandtemperaturegradienthole(TGH)D-V was”spudded on June 7.a a.:PhD Ag Ee 3.camp ract1it1é and Operation Camp facilities were shipped to Dutch Harbor in early April and some tents were erected for the use of the field geologists and environmental scientists.Construction of the entire camp was completed 81 approximately May 29 and full-scale operation began on May 30.The camp ee remained in continuous operation from that time until the completion ofTGHI-1 on September 8,with occupancy ranging from eight to:twelve persons.Physically,the camp comprised six "Weather-Port"type floored tents (one kitchen-mess.hall tent,one bath-shower-laundry tent,and four sleeping tents).Food stuffs,fuel,and consumables were purchased from Carl's Inc.and air-lifted to the camp or drill site on an "as needed"bess. ;- For TGH's D-1 and I-1,which were located considefabJé distancesfromthecamp,an onsite survival tent was erected and a/stock of food supplies maintained in the event that weather conditions prevented scheduled crew changes.The I-1 TGH location proved particularly troublesome from a weather standpoint and on numerous occasions crews : were forced to make use of the survival facility. 4,Communications a mee oo!'er re ee .:In late May,Trident Corporation installed a single sideband,high frequency (SSB-HF )radio system with one base station at the camp and one in Dutch Harbor.Unfortunately,the rugged topography made it impossible to effectively communicate from the camp to Dutch Harbor, although the camp could occasionally reach Trident's Anchorage base station.._ The system was modified in early June to a line-of-sight,very high frequency (VHF)system with base station units provided by EXSCO (the drilling contractor)at no charge.However,again due to topography;a repeater station,leased from Trident,was requiredto enable contactwithDutchHarbor.This VHF system eventually provided reliable| communication between units at the camp,the drill site,and Dutch Harbor. Q9 arContact with the helicopter was achieved by use of ultra high frequency (UHF)hand-held units.When drilling operations were moved to Glacier Valley (TGH I-1 location),a second repeater unit was required for transmission over the pass between Glacier and Makushin Valleys. This second repeater allowed communications betweenall base units and the helicopter as well. -Once the basic problems were recognized and resolved,the radio communications network was very effective.It is anticipated that the VHF system (or slight variations thereof)will be utilized for future operations. |f aaa eepity!vaia4 STAGE VI -TEMPERATURE GRADIENT HOLE DRILLING A.Move In And Rig Up These operations have been discussed under Stage V.H."Drilling Program Logistics*. B.Drilling Supervision ia Under the onsite supervision of Republic personnel,and/.4n Compliance with the generalized program attached as Appendix F,three temperature gradient we oe)were drilled and completed according to the following schedule:|Gt We | :;we '\TCH Total Depth -=- Spud Date Completion Date. D-1 1,438!6/07/82 7/14/82 = ET 1,501!|1/19/82,8/08/82 ae aOy)nee 1,500!-8/18/8200 9/08/82eerioaPeet:woe .-"TO ...ae ttle :Saar,panaAwom::we a .we, 4 wae : uo wd fo.ape te.LY lac 3 :a +.:.WE a be OE le soon 8 ope The first temperature gradient hole,D-1,required fmore actual driiting_time (28 days)than succeeding holes.A portion of this may be attributed to start-up problems commonly incurred when drilling in a new area;however,themajorproblemwasduetothenecessityofpenetratinganunexpectedlylongsection(1250+feet)of highly fractured and,in some cases,unconsolidatedvolcanicrocksoverlyingthedioritepluton.Drill hole conditions in the 7volcanicrocksoftencausedpoorcore'recovery and resulted in two time-consuming fishing jobs. ;Temperature gradient hole E-1,drilled at the campsite,was relatively-trouble-free.The diorite pluton was encountered at 40 feet"and dritling.| "proceeded smoothly to total depth (T.D.).The hole was drilled and completed ) in 21 days. The final TGH,I-1,was drilled in Glacier Valley.After some initial sloughing problems in bouldery colluvium which required moving the rig approximately 100 yards,the hole was drilled and completed without incident. The overall drilling time of 26 days included three days lost due to hole . problems prior to moving the rig and an additional estimated five days that were lost due to weather when,because of extreme fog,helicopter support was not possible and crew changes and refueling operations could not be accom- plished on schedule._ Detailed histories of the three TGH's are found in Appendices I-1,I-2, and 1-3.: C.Data Acquisition Throughout the drill operations,drilling cuttings and cores from the three temperature gradient holes on Makushin Volcano were collected,logged, -and stored.Drill cuttings were collected from 0 to 344 feet on hole D-1,O- _.._to 110 feet on holé E-1,and 0 to 100 feet on hole I-1.The remaining footage _.Was cut with NC,NX,and BQ size cores.A total of 4,430 feet of hole was »drilled and sampled. The 554 feet of drill cuttings were collected as 10-foot composite samples by sieving the mud return line until a volume of cuttings amounting to two | standard cloth sample bags was caught.These samples were then washed in clean water several times and stored in cloth bags that were marked in water- proof ink with the hole number.and the sampled interval. oo .The recovered core was washed and broken into two-foot sections.The .cleaned sections were then placed into divided,plastic-coated 'cardboard . boxes.The top,bottom,and other important depths were marked on the core while the sampling depth,hole number,and area name (Makushin)were recorded on the top and side of the box. o Both the cuttings and cores were examined at the camp with a 10x hand lens and an adjustable (10-70x)microscope.The examination enabled determinationofthelithology,alteration mineralogy,and fracture pattern of:the rocks. Rock chip samples were collected during the field examination for both whole-rock geochemical analyses and for examination via petrographic thin sections.The whole-rock chips were sampled every foot and combined into composite samples of 10 or 12 feet,and the chips were sealed in thick plasticbagsforshipment.Approximately 300 grams of chips were collected for every-sampling interval.Thin section samples were selected as téference for allmajortithologiesandtoaidininterpretationofrocktypedadalteration mineralogy. The whole-rock and thin-section samples were shipped to Los Angeles,while. the remaining cuttings and core were given to the Alaska Division of Geological and Geophysical Surveys (DGGS)for further analyses and study. OD Environmental Monitoring 6 0.3.3 Environmental "impacts resulting from the initial geologic work and the _temperature gradient hole operations were monitored in two ways:4p 'through site inspections in May,June and late August-early September by environmen- tally trained personnel from Republic and Dames and Moore,and from var tousregulatoryagencies;and 2)through.the environmental baseline data program.- As discussed below,environmental impacts resulting from these operations were-determined to be negligible,and the experience gained should make the 1983Thy!|operations |even less impacting.Be ata weet The site inspections were conducted in three different time periods whichroughlycorrespondedwiththedifferentphasesoftheoperations.-The site inspections in May coincided with the initial geologic work and set-up of the base camp;the inspections in June coincided with the drilling of the first temperature gradient hole;and the inspections in August-September coincided with the completion of the temperature gradient hole operations.The May and © 6 ww -- August-September site visits were conducted by the Dames and Moore Project CG Manager concurrent with the field collection of data for the environmental baseline data program,and 'the June inspections were conducted by Republic's7"Senior Environmental Planner and Dames and Moore's Project Manager concurrent with site inspectionsby regulatory agency personnel. Because the initial geologic work was primarily conducted 'on foot with helicopter assistance,no significant environmental impacts were anticipated.Observations made during the May site inspections of the temporary base camp- confirmed the absence of significant impacts.The following'observations,recommendations.and/or actions resulted from the May inspections: 1.The camp facilities were installed in accordance with applicable permit applications and approvals,with two minor exceptions as ° discussed in Items 3 and 4 below. 2.The camp operations appeared to be very clean,and in keeping withAlaskaDepartmentofEnvironmentalConservations(ADEC)Solid Waste | Disposal Permit.Burnable waste was incjnerated and,at this stage'of the operations,the residue,along with non-burnable waste,was flown to the Dutch Harbor landfill.Camp water was withdrawn froma small]stream apparently above barriers to fish passage. 3.The base camp was located on a plateau at approximately the 1,250- }foot elevation,jin the headwater area of Makushin Valley river and bounded by several sharply-incised canyons.The Dames and MooreProjectManagerobservedthatgraywaterwasnotbeingdischarged into a leach line,but rather was simply released over the edge of asteepbluff.Republic's field personnel corrected this by 'digging agraywaterleachlineinthelocationrecommendedbyDamesandMoore. 4.The Dames and Moore Project Manager observed that the outhouse was close enough to the edge of the bluff to allow some visible leaching of black waste water.Republic's field personnel corrected this C. =* problem by moving the outhouse to another location away from the edge of the bluff. At the time of the June site inspections,the initial geologic work had been completed and drillingof the first temperature gradient hole was under-__ way.On the first day of these visits only representatives of Dames and Moore and Republic visited the sites,with agency representatives joining the second day.The following observations,recommendations,and/or actions were made by Republic and Dames and Moore as a result of the June site visits: 1. PetOverall,both the base camp and the drill site were Found to be in excellent conditon.Both sites were very clean.Operations appeared to be conducted and maintained in accordance with the conditions of the various permits.Copies of the permits were located in a readily. accessible place in the cook tent and were available for easy refer- ence.Also,reminders of certain permit conditions and environmental concerns were posted in the cook tent.The onsite project manager_appeared tobe 'providing an environment where awareness of clean rere"operations and compliance withn permit coridt tions was known to have a o 7"high priority.« Some lumber previously had been blown from the campsite into thecanyon.Prior to the site visit,field personnel had retrieved allthatcouldberetrieved,but a minor amount of lumber stil]remained "perched onthe canyon wall.This was judged to be an unavoidable and-unmitigatable Impact,albeit.4 minor one.» a rR ps ne boee .. on the.first day of the visits,itwas recommended to the onsite:project manager that more dirt be used in the garbage pit after.the.burning of wastes.This recommendation was immediately put intoeffect;on the second day of the site visits the situation was cor- rected.° 4.The first temperature gradient hole was drilled in an area with very LO, poor,rocky soil,and no topsoil had been removed to create the site.However,site at the base camp was to be drilled in an area of tundra,where topsoil was thin and important to the revegetation process.Field personnel were requested to stockpile the topsoil cleared from the two remaining temperature gradient hole sites at the periphery of each site for use in site reclamation. 5.Field personnel were observed feeding an arctic fox which approached the cook tent at the base camp.Upon further investigation,it was noted that a fox den with two foxes was located approximately 100 yards from the camp,and that the female fox had begun approaching camp on a regular basis.The fox appeared to be unafraid of humans, and personnel had been feeding the fox table scraps when the animal _approached.The onsite project manager was reminded of the condition -of the Special Use Permit issued by the U.S.Fish and Wildlife Service which prohibited the feeding of wildlife,and was requested __to discontinue the practice.This was followed-up in a memorandum oRreportofthesitevisits.>a Cee Oe 6.The small amounts of waste drilling muds,cement,and cuttings produced during drilling at the temperature gradient hole site were being discharged at the surface on one side of the site and not being contained.At the time of the site inspection,the volume produced had been relatively minimal so the problem was mostly one of aesthet-ics.Recommendations were made in the field and back in the office that steps should be taken to contain the muds,etc.,in one area anddisposeofthemproperlyatthecompletionofoperations.These recommendations were followed for both the second and third tempera-ture gradient holes. On the second day of the June site inspections,representatives of the U.S.Fish and Wildlife Service and the Alaska Department of Fish and Game also visited the sites.A representative of the Alaska Department of Environmental C: an vswy.Conservation who was scheduled to visit,cancelled.Agency personnel who visited the sites specifically stated that they were impressed with how well the operations.were being:conducted,and with how only very minor environ-. mental impacts were created.- . In late August-early September,Dames and Moore's Project Manager observed the operations while in the area to complete collection of environmental baseline data.The following were observations,recommendations,and/or. results of the August-September site visits:a : 1.Temperature gradient hole operations at all three sftes had been very clean.Drilling mud was seldom used;it was often replaced with water.The mud that was used was contained in small pits and buried in the appropriate fashion at the conclusion of drilling.Garbage . had been removed from the temperature gradient hole sites to the appropriate waste disposal site.- ...2.The base camp and vicinity was kept clean despite the potential for.wind-blown waste scatter.Base camp operations continued to be,maintained in accordance with applicable permits,with only”oneexception(see Item 3).. 3.Field personnel were again observed feeding the foxes and were again requested to discontinue the practice.For the 1983 field operations a special effort will be made to prevent a recurrence of this persis- tent problem.The foxes may inhabit the same den and will likely approach the cook tent again for food.Field personnel will be instructed on how to discourage the foxes from approaching,and all feeding by any Personnel will be-strictly prohibited. 4.Environmental impacts from the temperature gradient holee operations were minimal.The operations occurred away from areas of environ- mental concern (e.g.streams,valleys,coastal areas).All drilling water was withdrawn from streams above barriers to fish passage.No an geothermal fluid was encountered,and thus no geothermal fluid dis- charges to.the surface or into the streams occurred.All equipment, facilities,and wastes were removed from the area of operations and topsoil?was replaced in areas that had been cleared for the drill- rig.All operations were conducted in a clean and workmanlike manner. The 1982 Baseline Environmental Data Collection Program (discussed as Section III.8.of this report and presented in Appendix 8),although primar tlyundertakenforotherreasons,was an additional tool by which environmentalimpactsresultingfromthefirstyear's field operations quate monitored. Impacts potentially could be observed by comparing the results of the May sampling of water quality and fishery resources with the September sampling. However,as expected,natural seasonal variations in water quality and fishery resources between May and September were many orders of magnitude greater than- any impacts likely to be detectable from the initial geologic and temperature gradient hole drilling operations.Thus,no impacts resulting from geothermal operations were discernible in the baseline environmental data. "wT aa STAGE VII -DATA SYNTHESIS AND DEEP WELL SITE SELECTION A.Analysis of Data from Temperature Gradient Holes The following discussion describes and interprets geological,thermal, and geochemical data derived from the three temperature gradient holes drilled during 1982 in the Makushin Volcano geothermal area. 1.Temperature Gradient Hole 0-1 : .we Teniperature gradient hole 0-1 was drilled on the heau adjacenttoFoxCanyon(Plate VII),approximately 1.6 km northwest of the base camp at State Plane Coordinates N1,183,750 £4,969,300.As shown on Figure 12,the hole was spudded in glacial boulder till 40-feet thick that mantles a sequence of Makushin Volcanics that extended from 40 feet to 1,222 feet.The volcanics are a series of essentially unaltered - porphyritic andesite and basaltic andesite flows (Photo 1)with | _.interbeds of scofiaceous andesitic cinders,lahars and gravel |(Figure 12).Below the volcanics,from 1,222"feet to total depth at1,429 feet,the hole penetrated a highly altered (propylitized)and. fractured,fine-grained to cryptocrystalline diorite (Photo 2),which is cut by an andesite dike from 1,370 feet to 1,393 feet (Photo 3).The diorite is intensely fractured and veined in the upper portion,with most fractures having near-vertical inclinations.Alteration minerals include suifur,pyrite,kaolinite,calcite,epidote,quartz,anhydrite, and chlorite (Photos 4 and 5).Most of these minerals are products of the reaction between the rock and high temperature (>150°C) at hydrothermal fluids.The quartz,epidote,anhydrite,and sulfur are primarily found as fracture fillings,although epidote is also found inthegroundmass.The andesite dike transecting the diorite 4s probably related to the young Makushin volcanic sequence. FIGUR TEMPE E 12 RATURE GRADIENT HOLE D-1 LITHOLOGY OF MAKUSHIN GEOTHERMAL AREA UNALASKA ISLAND,ALASKA lun ¢DEPTH(FEET)1,300 1,40¢ * 1,500 LOCATION:__N 1,183,750 E 4,969,300 LITHOLOGY DESCRIPTION SPUD DATE: 6/7/82 7/1 ALTERATION COMPLETION DATE: 4/82 AND MINERALIZATION Andesite Cinders Andesite : Cinders Andesite Gravel Cinders Aaphwenaviodnh 3 oben|Fk Uh th Oh TB Uh Tt pn ae FE Bee4+. rots BE yr vert wr ee reelPett,SikechaeltkeeSt Lahar, Diorite Andesite Diorite &peer ly sertes glactal ttl composed of variety offecktyperangingtasizefromwaltcote large vouléers entrained in &fing saney clay mstein. Black porpayrittc sesaltic andertte containing clear plagioclase phenocrysts IA an spnanitic greunematt. * &Gare grey persnyritic andesite containing clear plaqieclase prenecrysts In an apnenitic grousomast. A red spnanttic ctader rene. Dark grey perpnyritic ansetite containing cleer plagioclase prenecrytts 1A EA SDAGAIETE grewhans. hogan coring at 344 Peet, Dart grey,hard,Gente,porphyritie andesite © containing clear plagieciase prenecrysts in an apnanitic grouneeass that is sltqntly fractured free 382 te 209 feet.Sete the tap and bottom of tne flew are marked by 4 Fed Baked rene. Reatus grey,hard,dense,perpryritic ancerite Contaiming 0.1 inch diameter plagioclase prenscrysts In o@ apnanttic qreuncmase that ig Rtanly fractured. eo A black.hard,perenyritic ancesite containing plagiectase prenecrysts measuring up te G.1 Inch in Clameter in ah spnantti¢c grounemasa.The creck 15 higniy fracturee. A nediua qrey,hard,perpnyritie andesite containing plaqteclase phenecrytts measuring up te 6.1 trea in Elaneter 18 4A ApAantie grouncmass that contains qwiner heratlende crystals.feck it moderately fractured,Slace cinders inteorwtred with winer obsidian layers. @ phenocrysts svesuring ve te G.7 nen im diameter in da apnanttic growaness. Siiqnely freceured below 638 ft. A dart qrey,hard,glassy sncertte containing plagioclase phonecrysts measuring vp te 6.3 inen ta @lammter if an apnanitic glassy grouncmes Very winer herndlende crystals.Reserately fractured, A ewdtus qrey,hard,dente,perpnyritic glassy andetite containing hernsionse and plagiociase PRenetrytts meaturing up te G.2 inch in atameter ta an aprcaitic greunemats.Moderately fractured. &eedius grey,Rard,perpayrttic,glassy andesite leclaze prenecrysts ve te O.1 inch tn Sitentty te hignly fractured.@tandter. &peerly serted anqular uncemented gravel consisting. of a vartety of lithelegic fragments. A hare,massive,well consealiasted lanar that conststs ef a variety ef poerly sorted,anqular, Vitnelegical fragments ve te §Inches in Giameter sot 8 &Brown taney watriz. &Tignt grey,hare,Atqnty fractured, hornetenee crystals. freon. The rece ts lecally ttsined A qreentsn crey,Hard,perpnyritic ancestte containing ayrorens,hernblenee,ene plagioc onenecrysts.Few fractur: A meaiue qrey,Nard,mpcerately fractured Sryotocrystalline Glerite cometee of plagtectase one horaptencel erystets. Oratieg te %,438 feet could set recewer last core barrel,vast core ssowle at 1,629.5 feet. Rteer weatnertng ane a@uidation ' Mmoreximately 20%of the @ red entde ttain. Gow of the fractures aoe liqntly casted with 4 weiTewtsh tam clay. mm toe fracteres are Wignely costed witn 6puesbrowclay.'ene Me@lasty,qreen aatorial wetn a feemy texture |canes numerous fractures, Memereus fractures are Megnely coated with tan whey.;'wour very narrew renes of Wpelinttic clay and miner mrrite. oe MH eglatsy.green matortal worth a fesmy texture wats Aumereus fractures. M@ qtassy,green material ePARN &foamy texture mats Aumereut fracture. Srracture zene from $24 te oE27 ft. fled ane wlace cineers..Recovered only 4 feet ef core cryptecrystalline etertte competes of plagioclase smaji i Rene 3 A sarrow Leeliatte rene N St 1.211 feet. A Niqnls fractured ang atgnly alteroe siorite containing native sulfur, sytite,kaslinite clay, wearts, annyerite,z9eelites,and 7 calerite. Miner calerite with einer epteete a¢1,593 foot. A Rigniy alteros sterite contarning easlintte, annyertte sduncant pyrite,episete,ane cnlertte.ss29'a3aAGICIGINore.©Quarta,Ca ©Calcite, Thin Section Locationsx E =Eprsore.A ©Annyarite.P&Pveice,K ©Kagimte ie).Che lay,C ©Chiorne,2 ©Zeoute,§©Suitur .a -."¢ . .eo aep * PHOTO 1:Photomicrograph of porphyritic andesite from TGH D-1core at 376 ft. (2.5 x objective lens,with crossed nicols) epee ie *Ny FbSSey5MsPsBag PHOTO 2:Photomicrograph of very fine grained altered diorite from core at 1239 ft.in TGH D-1 showing secondary carbonate ,anhydrite and zoisite (?). (10 x objective fens with crossed nicols) PHOTO 3:Photomicrograph of a young andesite dike from core at 1386 ft.in TGH D-1 .showing porphyritic texture and alteration of the phenocrysts. (2.5 x objective lens with crossed nicols) PHOTO 4:Photomicrograph of altered fine grained diorite from core at 1429.5 ft.in TGH D-1showing alteration of the rock to chlorite and calcite. (10 x objective lens with crossed nicols) PHOTO 5:Photomicrograph of quartz,calcite,anhydrite vein cutting altered diorite *in TGH D-1 at 1429.5 ft. (10 x objective lens with crossed nicols) .to approximately 700 feet (Figure a Below this depth the temperature ( \ t 'ret :.nd _a Js ,ine "a A ve)il t int |”'°4b a ae)\uetTemperaturemeasurementsmadeinTa0h(Tabte 12)indicated We byessentiallyisothermalconvectiveconditions(ground water circulation)Gwin . increases at high rates (from 8.6°F/100 feet,up to 38°F/100 feet)in a conductive (linear)manner to total depth (7.D.).The zone of high temperature gradients corresponds with a self-sealedzone defined by the whole-rock geochemical studies (Appendix J).The gradient over the last 125 feet is 15.4°F/100 feet.This gradient is still very high (averagetemperaturegradientworldwideis1.8°F/100 feet)and it Wsgteates thathighertemperaturesexistatdepth,although the depthY'toy ffax mumtemperaturecannotbeestimatedonthebasisofdatafronfthishole alone.The elevated temperature recorded at T.D.[212.36°F (100.2°C)], the high gradient over the last several hundred feet.of hole,and the high-temperature alteration of the surrounding rock.all suggest the presence of a relatively shallow hydrothermal system. Chemical analyses for 12 selected elements (Hg,As,Pb,F,S105,Li,S,Ca,Mo,Zn,Ag,Cu)were performed on samples of the core.recovered from TGH D-1.Samples were collected over 10-foot intervals™:"and initial analyses.were made of 100-foot composites of the 10-foot oe samples.Selected anomalous 100-foot intervals were then reanalyzed at 10-foot intervals to define the anomalies more precisely.A detailed report of these analyses can be found in Appendix J. The D-1 core is strongly enriched in Hg from 300 feet to 500 Feetandfrom1,200 feet 1,300 feet (Figure 14).The upper enriched zoneshowsnoassociatedenrichmentoftheotherelements,whereas the lower feks '<nintervalshowscorrespondingstronggainsinAs,S,Li,and F.These other elements are also enriched in the 1,300-foot to 1,430-footintervalwithaconcomitantdecreaseinHgcontent.These chemical Ra OMectJore patterns suggest that hot water (>200°C)has been in contact with the rocks between 1,304 feet and 1,393 feet (Bamford et al.,1980).The thermal data does show a decrease in gradient in that interval,but the measured temperature is still below 100°C and the likelihood of a-(ompa(tvg ta {ony bh --_)Jas db Se (pie °Cyn oom cubs puls 2 TABLE 12 C. _TEMPERATURE DATA OF TEMPERATURE GRADIENT HOLESMAKUSHINVOLCANOGEOTHERMALAREA ; '/UNALASKA ISLAND,ALASKA TGH 0-14 TGH E-1 TGH'I-1 9/18/82 °9/15/82 9/18/82 9/18/82 Enviro-Lab>Enviro-Lab>Kuster”Enviro-Lab Depth (ft.)Temp.°C Temp.°C Temp.°C -Temp.°C Surface 9.8 8.0 (air)L 13.5 25 44 12.3 100 $8.9 16.0 *fF 16.3 200 .8.2 36.3"'23.2 250 , :41.8 2715 46.0 300 7.5 57.3 "46.9 350 49.2 375 . '49.5 400 8.4 79.4 50.1 500 9.8 97.1 (water)59.1 550 104.6 59.77 690 9.7 1711.2 a 61.3 650 _118.2 °63.a675oo,OO oo -121.4 mp ee os _700 ;10.90 ;125.3 113.6 .64.on726eeoe129.2 ee ) 750 Ce oo 132.5 9°=ey Te -65.2 775 oo 135.8 |te 800 16.1 139.0 130.1 66.5 825 142.1 850 145.2 300°20.4 143.7 . 69.2 950 69.7 1000 '34.4 (no measurement)70.7 .(clock stopped) 1050 a 10.2 1100 62.8 173.3 71.7 1150 ::71.8 1200 an 71.8 -186.4 74.6 1250 ..75.0 1300 89.5-oo 190.8 :715.2 1375 -°79.4 1400 96.0 192.2 79.8 1425 99.8 1435 100.2 1450 78.5 1475 77.6 1485 195.0 |C150077.5 aTGH-Temperature Gradient Hole Dtool used for measurement 0 ee 'FIGURE 13 . TEMPERATURE GRADIENT HOLE D-1_|SPUD DATE: TEMPERATURE DATA OF MAKUSHIN GEOTHERMAL AREA 6/7/82 UNALASKA ISLAND,ALASKA COMPLETION DATE: Dee es eee .7/14/32 LOCATION:_N 1,183,750 E 4,969,300 y ye LITHOLOGY TEMPERATURE °C wi i OQ 20 40 60 80 100 120 140 160 180 200 '3 TH, --Ge 100 - an ie Fa a yeftyX ;+400 *bsx oie?any AndesitaSeesteehee woOofs)ist:Tole)ecmerrnernaeresperupocsceaterneSoeur Cinders 700 +]Andesite DEPTH(FEET)0-1 FOX CANYON 1 Gravel R.E.Y,9/18/82 dcinders _\ ehrit atemetats dahonan tsSatbatndebodedabraded:dake nz tates |veBabbatededamthadl"amie aie harendhFinBeachatLa1,200 Fae 3TERESAPRETNTRTEERShef+©©©©©. 1 ,30 re)Oiorite *xie ¢©©©©@ .re FH aH oO et140gavertetesfa]Andesite 2°; . ; nes 100.2°C @ 1425' : 'bl Srerererarares Diorite \T.D.1425'HECe?Thin Section Locations « 101 7 S88 hua ie,AAO a oe ranean 1?gf e els sy ° ._.FIGURE 14 DISTRIBUTION OF INDICATIVE GEOCHEMICAL ELEMENTS IN TEMPERATURE GRADIENT HOLE D-1 :Hg.Aes So Lie Fe Cor $102,Cue Her Phe ond Zn Getne &Leoeese (Cal)'we Depth fer binpoctte (100-feet)Cuttinge end Core Samples from Drill Hele O-t- te mo,Mount Makuchin Prespect.\Unotoske Leland.Aleska.® PPB He Oat PPM Ae OaL |;XS OAL pen Le Gal PPM F GAL X Co Oa X 8102 Gal PPM Ce O8t PPM He Oat prt Pe Oat PPM Za al749.200,0 10.6 09-9 0 =.10 1.09 0 3.20,°-300,400,r)»4.00 4.09 0 ¢10.00 10.09 0 =100.200,0 F?8,0 S$.20,0 >100.200, ' 4 c q a a q ...y = .==6f so.0 f ."2.. +¢ ."hy7ee'a }nn ®Rae so if i}+30 CI -a-se '2 if 0 ' \Bo 2. "2.2.8 Ot :"5. q -20..0 f .032 -.00 33..s.t. 2 2 .at rEg ree 2f at 2}fb 2t 23 -3.6.8 j -02 F |a .+EF |ond 3 +'3.F '.."4. 3 5)9 3}.oE af 3 3f H 3 xf 300.4 _4 *04 |2 ;"90.F<|was : 2.40 ar .»'az. 4 4 'at HH ee 3 4 4 at 4 4 ae-q ft rr)+00 s -40."34 3 "1.80 23.®Fy 10. 5 5 os 5 5 5 5 st L 5 5 3.<8 +00 Yr =10.ota 2.30 e '..4. 6 6 Gir 6 6 6 6 6 r 6 6 e.3 00 oa."10.an 228 «40 =.6."le 6. LU wee '?7 7 re ??r ?7 "3.a 400 A ao.”OE oa -.20 ®.'"6. 8 8 ,a 8 8 8 8 _Of 8 7 ae.7 -.00 ot oto.|AZ $030 »|3.e. of $9 9 9 9 9 9 9ia.tn +00 a4,'230.3 708 7-20 f hte of ..e .ode 'e of .e ol.3 ."40 *0 of *10 tl any)a "sof "vot ' e.e "00 ®.E ..100 :100 '2neTyaTFa0:ne "ON ng ;. 4 .ote Pe +20.a #a |"0.|e ll anny)|*ak ]1 FF oR yak LST ak o tL vat ©vat . 204.-4 36.4 mn i"{wae "2.4 ae ot oat.it : @.ote. ;j oak : .[i 30.9 [106-4 [We [:aor.[:-.08 [2048 [f a4.['.[;e.[ot. }a.ry tee nay ft v7]eee |ha FE |Ja-20 | e100,"ft ."PT o4 16. | : ae i Bo i : | 13 se"15 1s?15%137 1%13 1s%1s" Nolet Depth choon tm 100 fool unites@Plottedvaluceereepperont getne &lecvee (OAL)coleolated by eubtractingRechgreundvalues(lebte 2)fram original geechemtael date (Appendin DieoOIndtenteesoneofpovetblehetovelerentriosfeoeFableI). significant,present-day water entry 1s small.This interval may have been a zone of hot water movement in the not-too-distant past which js, however,presently sealed.The rocks between 700 feet and 1,200 feet in TGH D-1 appear to be self-sealed and lacking in significant fractures. They probably constitute an impermeable cap for the reservoir in this area based on the general lack of trace element losses or gains in this interval.Although the stratigraphic section between 700 feet and 1,200 feet does contain cinder and gravel interbeds which one would expect tobeporous,the temperature profile shows a marked increase 'n gradientindicatingaconductive(no vertical fluid circulation):T ime.In this case,both the geochemical data and the temperature dataAndicate the existence of an impermeable cap.OQverail,the geochemistry from TGH 0-1 suggests proximity to a geothermal resource having temperatures inexcessof200°C. 2.Temperature Gradient Hole E-1_|\'jul ( "aTemperature”gradient hole E-1,"which ts located at State PlaneCoordinates.NI,179,200 £4,971,650,was drilled:'near the base camp,'closetothecontactbetweenthetuffsunderlyingtheplateau'and the dior iteoutcroppingonthemountainside. _* The E-1 hole penetrated a sandy tuff from surface to approximately 40 feet.It then encountered weathered diorite which quickly graded into relatively fresh,hard,massive diorite (Figure 15).The diorite extends from 40 feet to T.D.at 1,501 feet,in marked contrast to the D-1 hole where andes ites and other volcanic rocks comprise the first1,200 feet of hole.In general,the diorite in TGH E-1 is massive and fine-to coarse-grained with hypidiomor phic-granular texture (Photo 6),although the upper 300 feet are texturally more like a porphyry. (Photo 7).The diorite is generally propylitized,but the degree of alteration and chloritization can vary dramatically over distances of a few feet (Photos 8 and 9).Veins and fractures are present throughout the hole,but are commonly found in 10-foot_or 15-foot thick zones oN som FIGURE 15 TEMPERATURE GRADIENT HOLE E-1LITHOLOGYOFMAKUSHINGEOTHERMAL AREA UNALASKA ISLAND,ALASKA Lc N DEPTH(FEET)a900 1,000 #1,500 LOCATION:N 1,179,200 "E 4,971,650 LITHOLOGY DESCRIPTION SPUD DATE: 7/19/82 COMPLETION DATE: 8/8/82 ALTERATION AND MINERALIZATION ee Srowntsn grey st1t and sand with 9 little clay ene wentneregpaaSandyTufflaterowdsofash(vttrie tuff). 'ek ik dak tol Tok Sok Toke to.Gark grey.course grained crystalline,locally+¢©©©|Weathered Diorite weathered te clay." >¢+©©©©4 Diorite ._ §.eorererere a tor .Medium qrey,mederately course grained with seworad |ctey jeutertuat),seltenst-=(Began Coring @ 90')|fractures tines wien clay minerals (200ttterys Qe*age (4Leeorerenefractures6.5 ma wide with 48°to vertical attteudes.Tate etnerettont terttel c.gooe+©e+©©semmanet eyrtee ae?»©oe ¢@¢a a Same a8 above with tome biotite crystals.Conan torre wtaorstteed wetoasetay.§C,9,ofo©©©@ »»&|Diorite cdiertte ant lecaiitene latome c :Otertte becomes fine grained at 125 Ft.or \ttastien,te wees Ste>+©@ tees 1"+¢6 ©+"Goce becomes course greineg at 180 ft,calerstae a Ses ete heed>++©6 &Precem fresh with minorialized zene at 177 Ft.Frese |sities,epiecred ona oprite «ec atetite crystals ia dierite.nee _-Leeatty s18 te we>+©©©©+Several hiqn angle fractures vith argiliie 'comet wotonsorrt:Ce a er 2rye+mineralization (cnlerite?}less bietite,are fewensitet)oon eo a "” eo ©©6 @ @|hernalende ef pyrezenes at 240 ft...first gresmanase ff (eral 050 stitconee wens,pyrite £%.£,@SOCSRESESEwetaetenreetfeeettnwere:Me ES>>eo ©©©@ 4 Finewandiun qratned dierite.on.Vt"Precterwestertta,clay,e Pyoe¢©@ Oe 6@ Wetite-nernelense diorite with meqnetite,lecally owen.Gave-F ©oo ©©eo .thows stltea commented brecctated tontere.&foo cone stiten weten,sprite =e'sg.9,cooo++ ¢1°section with senolttas at 263 ft.--,e ¥7 Saft argiliic section (sessy texture)”-°*Sf Caeltertel,syria,st tvea 3 272 Pt.=zea rt _DSM eens eotelees ormane 273 #8.1 ct"ee ©©©@ °° -aa>©©©©©@ 4 p 96"ee ©¢@ @ Diorits Several snear vertical frectures with "prene tite oe °>©©©©©©ff ViOri °coatings,a8¢$eoe¢¢¢©Srounomerg cnleritized weerty eet >©©6 ©©©At 353 ft.,7S°fracture with *sttcxensices secanating Reeat e2lteteteerten,atner "eo ¢©©©strshe site aetton.waite "svpobre esa i 1$+¢6 ¢&+fear vertical open fracture with quarts erystain.waved tng Chom?oe .8e+©©©©O 8.Otssawinated groundmass epteste.meer wertical ttitcooms weens,iPerensOrecctatexturewithsomehernfelstccenelithe.eee lly argiiiic,locas '.*.°,°Kenelitne Casemmnated wrens.oor.°°¢ara aetiua grain atorite with nernfels seootsens.|isitteesmerwerttcat wey [te f €lite aike at 657 7%.with fine bietita,atttes.P "er @ @ +'a)veins and fractures.Moe crlertta,tecaltees epteces.."7 +++@ Some nevelitns;at 482 ft.large asqnetite crystals selven, poorer rey:ané clusters ef horns lense.Mesumest,oy7 the he-eto = 4.re *.°bd ...2 ft.vertical fracture with chlorite and reeltte®Vesatty sitverrted,t as,eo ++©oO 4 ..Aise titice vote with quartz crystals ta ascstew Tere steed .9°.bd .*¢.bd .°.°e Diorite Retsive diortte with nernatenseind bietits.. Commun enterstitasten,euteote waved &E.& "ervrve e note:ST core te $76 Pt-;£1 ston oOa"orev a Fine qrained diertte.Cee ee eee EE 7 wee s *freth,mative éierite,seanly en tertei nes."7 € ++Qe "evre8¢©Relatively fresm,fine grained,sastive with Vigne att Rteirves veqisentests,wast a»+o +qreon tint. ¢-¢©&&@ +@ ° . .er eat ftiterug wtetets e°"*letras votePereraerrrmneet:Moar cnlorittzarren,tecat age [ie angle wetoes ttlten emp wereyrroe+©e ©O .Oterite richer in merte minerals,massive aooyertte end meiite QAazoe¢@¢@ ©6 & °Severe'vetersmau clay arsvttien.fci,@ cP.--aleita,aunt oyrtee €Py "+e :*Winer colertetsettes .°>©©©©©4 .Sttteacceterite seve ot 720 ft,fe S oo a er . :1ameayriatteeeterseae tree ES &>©+¢©©©+Dijorite Rattive,fineasvetum grained,fresh mee caleontranetee?'nes! o¢¢¢©@ +Wries/instiates ond syrven oe >ore eee a Sigatly eore felsic oe Se A a ee a 2 Gear catertta,ait cotascatertts jf.#.©iT -Srarar ae ae oe oe Felsie bending,bulk chloritization igvestaava sttven 6-.*+©FT aarpoe+eo ©@ ol4 Fresn,encopt for bulk chleritization ef the recs.'srvema vores ° bd «.:-Wereveteing of eiitea amt ¢>o>©©©o @ i;tag e*¢oerft ee ©O@ @ Quarts moar Valivat wagetovetenensais.d .°°*¢be Silves cat asa ltesee wereGrararerorereSliqatlycalertttzes ae Passive,medium to dart grey with greenisa tine,@teevelinue Crecterercaletta € >+&©©©©courte qrained.a7->r>ee ©©+@ >+©©©©©Locally fine qratned,siigqntly mere calerttized,€ore ee ©F Diorite : tree.-@ cale.,s8ltea,epee.©>¢©©_°*¢Locally cnlerite rica.OV".982°008!code.bide wanes L Qe¢*+-¢©©@ ¢wll.of,ate>@¢6 ©©©@ # "eeee8ees .Plagiociase clear unattered.Caletee 6 611000 ete eregr.a te "eve o Commen chlorite forente etisenesee treet,|*9 * Y_+©©ee e .Cotecte comem oc 1,057 4,bg e¢+©©©©€Carette :a .o¢eo ©4 Caleritized eterite body podiatedi Unt ne.to.86o"oe @ Pp e+e++©o +4 Vee 0 ontd.,comer cate.&sities Ft,ta.©oo ¢©@©©@ ATW sites enerente.&wn.. it © e¢©©o . -3.11.13"ert wetites Seats §6.Ca.8.0Sam.ota,idgarerererereret3"acters at Trin on.ante.harnge088.Boye.Leta.&oye.terrens>©©©©©&4 Diorite Massive chlerttized cieritea,course grained.aetes 1.528".* ”tae [-a}ooo ++©©Tiare'OATS trae.w cate.8 Lee>>&+oO eo &Mase.sore O11,180058°.onpyy & ¢¢©@©6 @ @ on.we...bd t.Ga,&, Ln st ew et Retstve,Nard,courte grained,cnleritized.cate beth:corestegromemare,19,8°ry °e °°bd PerEneied ©Prrite &optente °.+ oParerarerererVeryfinegratnedSapiite®eine 1.207 ft.=ZTE Fe.Frere "Sit cele.&ope..re .>+>©©©©@ 4 wigniy cnlorttized Lehn an wt.sttecg +>-f-©©©o ye wevescreticuttiag vores st Af*s,28,fiJeritizes,ne fractures but ToRa eed eer ones te wet se .Pane eo oe ee Merea tyeties enter seizes,trectoret,cuter ttitsqtem,aliergs o¢©Ohm UH Course crystattiine dierite,cnloritized,ne votes oryaaaadnferacturet.anew°°°Ad a >°- *-¢¢©©@ tore canter.aleve tp cley-e¢©©©©&@ beborns oss -1c ry..Tacrve .* ..¢¢©©©©©IDiorite Massive,menetenous diertte 46 aneve,Meatieres even.erie s>oo oe e+oe ©@ tee want)Sti \ecue wotet gtooo+©©©©@ Less cniorttized,Sarcer St tvea were @ 1,200"&3,388.:perenne SawaherLinee erat mit:"°*¢¢++¢Less greenisn color,more grey,cnlertte still cuamen tore.tar ae Wises:wores ot Ha hewe36. -¢©©©©@ Beirees oeove.h ee ©eo 6 oO a MAtsive Course grained.grey-green Siorite Gaartanca teri were on 3.70647 v1.phe GFoo©©©@ @ S11 enagere,oose 1,60RnE?", a Leceecale,wwre @ *ares>2+©©©©©vereinatow wz eryeists.oe ©&@ @ Ctamtale.were @ }673°238°.omooawereqeren eo.Passive,coarse crystalline,grey-green,enloritized,|Diorite ' 'a +o -C2 *-ca - Thin Section Locations * Note:@ ©Quartz,Ca =Caliente,E =Ennsote,A *Annyarite,P ©Pyrite,K @ Kaolimre,Ci ®Clay,€=Chiorna,Z ©Zeointe,§©Suttur 104 HGICO6t We xdstecSonieae'si,? " aBeo PsaCe8 est:ee p. aah ctSN diorite from core aticiomorphinedhypihofcoarsegraPhotomicrograp 1. lens w in TGHE1379ft. PHOTO 6 icols)th crossed nivet5xobjec(2. NGshowing coarse crystals surrounded by finer grained crystalline ground mass. (2.5 x objective lens with crossed nicols) BRPHOTO 8:Photomicrograph of altered diorite from TGH E-1 core at 616 ft.showing °alteration of rock to clay and some chlorite with a chlorite-carbonite vein cutting thru the section.(2.5 x objective lens with crossed nicols) MO. otpeAePOsat: .PHOTO 10:Photo of TGH E-1core at about 1220 ft.showing near verticle major fractures at about 45°angle to the core axis. ear'aseparated by massive unfractured diorite.The major fractures are dominantly vertical with the smaller fractures and veins dipping about 45°to the core axis (Photo 10).The alteration and vein-filling minerals are essentially the same as those in the D-1 hole,with quartz, epidote,and anhydrite representing the higher temperature hydrothermal alteration minerals.Some portions of the core are pervasively altered to epidote.The diorite is cut by an aplitic diorite dike at 457 feet. There appear to be at least two episodes of alterationof thediorite.The first is a pervasive propylitization that-resulted in itsgeneralalterationtochlorite,carbonate,quartz,and e idote.This 'was followed by localized hydrothermal alteration along joints or fractures by-high temperature fluids (>150°C+)that may be related to a past,or to the present,geothermal system or systems.Several of the veins and fractures show at least.two depositional (vein-f41ling) events,with layers of quartz covered by layers of anhydrite or calcite, or chlorite-lined fractures filled by younger quartz,epidote,or a_ combination of minerals.This situation indicates that these fracturesonwereeitheropened,sealed by mineral deposition,and then reopened andsealedbyasecondperiodofmineraldeposition,or that fluids of at least two different 'compositions flowed through the fractures at different times.The reopening or maintenance of open fractures 1s strong evidence of active tectonism,and the deposition of high temperature minerals in these fractures 1s good evidence for circulation of hydrothermal fluids.Similar features have been found in many active 4 ay Jgeothermalsystems,usually in the self-sealed zone overlying the reservoir.Their existence suggests that fractures are open and |fpermeable,thus providing conduits for fluids from the geothermal - reservoir.This evidence is reinforced by the existence of a zone in which circulation of drilling fluids was temporarily lost (1,360 feet to 1,420 feet). ) 1na ) neCASS)The temperature profile in TGH E-1 is essentially conductive from surface to T.D.Gradients in the first 1,200 feet are quite consistent and high,and range from 22°F/100 feet to 26+°F/100 feet (Table 12 and Figure 16).At 1,200 feet,the profile begins to roll over and-the gradients decline abruptly from 24+°F/100 feet to 3°F/100 feet over the last 285 feet.This may indicate that the hole has nearly penetrated the self-sealed zone and that it is approaching a hydrothermal System in which hot waters are circulating.fi.a ” se .+ The high temperature [383°F (195°C)at 1,485 feet)Ancountered in TGH £-1 is'well within the temperature range for commercial electrical ° power generation.The fact that this temperature was achieved at such a shallow depth,and that the gradient indicates a possible hydrothermalsystemnearby,strongly suggests that if enough interconnected fractures . are available to provide a large enough reservoir,an economical commercial geothermal system may be present. Analyses of core samples for the elements described above under the --description of TGH D-1 were also carried out in TGH E-1.The results of -the multielement geochemical analyses for TGH E-1 are summarized in | Figure 17,which was taken from the detailed report (Appendix J).The same type of geochemical anomaly [enriched Li-F-As-S-(+Hg)]is found in this hole as was found in TGH 0-1.The Hg-F enrichment is confined totheupper500feet,with minor As,S,and Li enrichments which are not always coincident with the Hg-F.These anomalies may be remnants of an older <200°C hydrothermal system.The most interesting portion of TGH E-1 is the 1,100-foot to 1,400-foot interval,where Hg is only slightly enriched or even strongly depleted in.association with strong As,strong S,moderate Li,and moderate F enrichments.The chemical patterns - suggest that there have been significant hot-water zones between 1,190 feet and 1,400 feet.The chemical evaluation of cores from this hole strongly suggests a high probability for the existence of the target reservoir of >200°C fluids not far below depths of 1,500 feet.In - PHOTO 9:Photomicrograph of altered diorite from TGH E-1 core at 781 ft.showing epidote-andhydrite vein with some carbonate. (10 x objective lens with crossed nicols) The temperature profile in TGH E-1 is essentially conductive from surface to T.0.Gradients in the first 1,200 feet are quite consistent and high,and range from 22°F/100 feet to 26+°F/100 feet (Table 12 and Figure 16).At 1,200 feet,the profile begins to roll over and the gradients decline abruptly from 24+°F/100 feet to 3°F/100 feet over the last 285 feet.This may indicate that the hole has nearly penetrated the self-sealed zone and that it 1s approaching a hydrothermal system in which hot waters are circulating.r The high temperature [383°F (195°C)at 1,485 feet]vencountered inTGHE-1 is well within the temperature range for commercial electrical power generation.The fact that this temperature was achieved at such a shallow depth,and that the gradient indicates a possible hydrothermal system nearby,strongly suggests that if enough interconnected fractures are available to provide a large enough reservoir,an economical commercial geothermal system may be present. Analyses of core samples for the elements described above under the . description of TGH D-1 were also carried out in TGH E-1.The results of the multielement geochemical analyses for TGH E-1 are summarized in Figure 17,which was taken from the detailed report (Appendix J).The same type of geochemical anomaly [enriched Li-F-As-S-(+Hg}]is found in this hole as was found in TGH D-1.The Hg-F enrichment is confined to the upper 500 feet,with minor As,S,and Li enrichments which are not always coincident with the Hg-F.These anomalies may be remnants of an older <200°C hydrothermal system.The most interesting portion of TGH E-1 is the 1,100-foot to 1,400-foot interval,where Hg is only slightly enriched or even strongly depleted in association with strong As,strong S,moderate Li,and moderate F enrichments.The chemical patterns suggest that there have been significant hot-water zones between 1,190 feet and 1,400 feet.The chemical evaluation of cores from this hole strongly suggests a high probability for the existence of the target reservoir of >200°C fluids not far below depths of 1,500 feet.In a FIGURE 16 TEMPERATURE GRADIENT HOLE E-1 SPUD DATE:TEMPERATURE DATA OF MAKUSHIN GEOTHERMAL AREA 7/19/82 UNALASKA ISLAND,ALASKA COMPLETION DATE: 8/8/82 LOCATION:_N1,179,200 --«E.4,971,650 .r .LITHOLOGY TEMPERATURE °Cnse020406080100120140160 180 200 4 Sandy Tuff °a? eos»©©©©©«of Weathered Diorita be oe eo +og Diorite106)a [oar ae ee 2 (Began Coring @ 90°) o-¢ ++oo ©so¢©©©+©af Diorite.6+ee oo of. ere eo +a200oe©@©©©@ ooeoad..et at Clarita. pote °. .oat e ree ete .E-1 CAMP SITEEnvirolabTool 7+ee oe ;.REY&LW..iP..¢©©©©of Diorite:9/15/82 Diorite . +DEPTH(FEET)>©o>©+©©145.2°C .SOO ;(293.36°F] 900 i a "eee eee AT =500'-850"=24.73°F/100"Peaew eee |Diorite __,700°-850"=23.88°F/100°Piet elt ee 750'-850'=22.86°F/100" 1,000rSeSeerererer PoP erar ar ar are R.E.Y.&LW.|gerererwrorers:.:qa,9/18/82yeeoeoo©a ::Kuster Tooloo.: #L°.%.%6%.%.%,°%|Diorite 4T 1200-1485°=3.02°F/100" -¢¢©¢©©+4 Diorite 7 Paraeerererere AT 1600-1485"=3.29°F/100" .wd >Cd cd o *" eo Cd cd cd *Cd o 3wererererererea3 ree.%.*.F Diorite 195°C =3583°F@1485"|]3*1 'S 00 Thin Section Locations *:Plot by GWH 9/15/82 CFI 9/24/82 112 a PPB Hg al -40.700of 0 $6 "1 0 20,0 =10)400,f)-4.0 10.090 10.09 aoe.-4 |140 |a a 140.;-1.5s 40 't eae 1 1 iF if aM.a0 :18 1.40.i "1.95 20 2 2 .'2 2F 2 2 4 2 200.4 ]20.8 ' "a +..se0.-4 3 -t.42 2.60 3 ae 3 3 3 Jost LI 3 at.3.4 otf 3.330 °-8.97 2.990 4 4 ath,4 4 |at 4 or ae j AY)1.400.-4 -I oe j 40 5 s stl sf 5 5 5 ;1.or 4 @.|50.E ater 4.00 6 6 6 6 6 an |=ef a2.3.0 00 '.20,[o2.a2 are ??Bae 1 ?rt LA ?J oe..3.8 |oft ve F ](oo,-1.00 30 8 ®®8 8 8 a '8 e.i)-00 6.®. , +00 .00 9 9 /9 9 9 4 9fa 9|32.160.8 os 2.+[200--7.00 20 19 to sof 10 to "10 10 -20,10.8 AY a 130.2.33 +99 """|.any)"." rt 22.8 "08.ry tee.o1.20 +20 Tr |:7|ts [1.04 [bsddag [he |Sts |Pry}|]rT) )13 vw )if WS Uy 13 : t |-".[17.8 lL}a [a [re.L .atte [+90 ":* 3 .;;he on -u.10.8 |08 a ee.7 "18 le15}-1s 15 15 1s ons oa as (6 16 16 16 164 ,16 16 PPM Ae OL 10.9 00.8 x 8 O8L 10 1.09 Hg,AveDepthferbine fn Le oat @e Ss.eotte (100-foet)Cuttinge and wk es =2 2 RyOEMd, '+FIGURE 17 DISTRIBUTION OF INDICATIVE GEOCHEMICAL ELEMENTS IN TEMPERATURE GRADIENT HOLE E-1 Li,Fe Pen F gal O. Ca, Meleet Depth ehovn tn 100 fool entitles@Pleltedvoluceereeppsrent geinebechgroundvaluce(Teble 2)from original geochentoel dete (Appondis Die>Indicates ene of pescible hel-weler entrice feoe Table I). $102,Cue X Ceo OaL 00 4.09 Mo.Pb»and Zn Getne &Leseee (GAL) Core Semplee from Drill Hele Ent,Mount Mehuchin Preepects Unelecks Jelend.Alacha.® K 6:02 Gal &fecece (OL)cnleutated by eubleocting Prt Pe oat20, PPM Ce Ott PP Me oat 100.2004 0 2. ons. : be |a °33.3 ie 2 = "60 te -3 H] 48.te 4 S|"20.|2.5 S 740.. 4 ef -4. 3 iy 7 L 0.a. 8 e.e. e Ga ie LD i. baad @. is 18 Ln94 2. PPM Za Gal oe:200 3 |ae. 1E 2. otF |-40.3F F3 "4. 4 18. os ; ve, 6 1 . ? ve. 8 e. 3 36. 10 } 32. at 1. hw vst ii a. 26. isf =U 16 AGL C379 our opinion,the high temperature,the subsurface geology,and the geochemical indicia encountered Justify the drilling of a larger,deeper exploratory,well., 3.Temperature Gradient Hole I-1 Temperature gradient hole I-1 1s located in Glacier Valley,approx- imately 5 kilometers south-southwest of the camp and TGH E-1.The State Plane Coordinates for the hole location are N1,164,100 £4,964,650. Stratigraphically,TGH I-1 is very similar to TGH EA,as shown on Figure 18,and confirms the hitherto unknown wide distribution of the diorite intrusive body.The hole was spudded on the remnant of a terrace underlain by glacial til]and some pyroclastic rocks:about 40-feet thick.From 40 feet to T.D.at 1,500 feet,the rock drilled consisted of massive,cryptocrystalline to medium-grained diorite . (Photo 11).The diorite is generally propylitized,as in TGH E-1,with _alteration minerals including chlorite,quartz,carbonate,clay,and- )epidote.Some portions of the core were less altered.The upper third of this hole contained pervasive fractures commonly Tined with pyrite,- quartz,and epidote that were deposited during an older,high-- temperature hydrothermal episode.Fractures filled with a variety of secondary minerals were,as in the other holes,distributed throughout the bottom two-thirds of the hole.Although the fractures in the lower part of TGH I-1 are filled with pyrite,quartz,some anhydrite,and epidote (Photo 12),these high-temperature hydrothermal minerals and fractures were not nearly as abundant as in the upper portion of the hole or in TGH E-1. : The temperaturedata recorded in TGH I-1 (Table 12)was quite different from that found in the first two holes (Figure 19).The profile indicates two separate thermal regimes.The first is a shallow (surface to 225+feet)system that produced large flows ( 150 gpm)of 18°C to 25°C artesian water while drilling.The second system extends 114 ° FIGURE 18 TEMPERATURE GRADIENT HOLE I-1LITHOLOGYOFMAKUSHINGEOTHERMAL AREA UNALASKA ISLAND,ALASKA LOCATION:N 1,164,100 E 4,964,650 LITHOLOGY DESCRIPTION SPUD DATE: _8/13/82 COMPLETION DATE: 9/8/82 ALTERATION AND MINERALIZATION Till A mtzture of glacial {11%and ttreem conentts witm |none ne .asm layers.. é we A Vignt-grey,hard,dense,Rignly frectured Aburdant pyrite,grees oocrypecryetallineaieritethetgracesfromweatneredClay,calcite,quarts,natefresmrecs.manierite,optdete and , 20°e uaclintte,9.8 9,et 7)Raetinite renes ot 161 '.at «and 109 feet °1 °Quartz vein at 186 feat.jf-Haha 'Alteration unten ts e A Blact,hard,dente,erypecrystalline dtertta tnat aie teeters out [cetsovearstehaveunsergoneainerreerystallization,mar bdAporonioatelyonefractureperfestandabensastpyrite.One 1a.2°foot thick quartz vein at [?.& foot.A dart te \ignt grey,doase.eryptecrystalitas mreety titeres Norte &Cota=,oo +©©©6 os @orite containing plaqieclasa,pyrevene ang tne iveing sec:a8°«««|Diorite nornelonse crystals.Niqniy frecturee between #23 8e¢¢od Orrtte,epiceta,calcite,Loo +o +o +Oo fhe and 275 #2.340 FR.an 366 FR.STI FE.amd 38O F cares,ctap ang aetHoeee0+©2.©U2 FR,Rumerous mineralized,sealed votnl cut cmlertta.. 300 =>++o 6 ©6 @ ©]the élerite,'7 es ie | -a Mager alteration renes A+f.Parererererer fs are pyriteveinsat223 fy og &q oe oes *E.©281 1t.,epteste oe"oe oe wetm at 260 1,erey Slsy [eo++o ©+@ at 267 fR.,calette at wea7©eo H+oO WOO ft.clay ,pyrtte, ->©©©©@ 4 ang calcite at 306 ft,Se |4 fo)fs)+c3 8 ,ca -¢4 "e+oo 6 @ fero©*,°re A dart green,nard,eente,fine grain te .YS Ne "ee oe eal Dier:erypecrystaltine diertta contatning plaqieclase,°r.°+©©+@ Dio te pyrenene,and Rarnslende crystals.Medoratety ie: o fractured at 4646 ft...between S26 ft.$46 ft...andPererererereDetwoen461Ft,=643 FR s'50 "of ©@ @ ©7°be0f+©++© =>+©©©6 @ 4 oe eo ©HO @ >¢©©©@ @ 4 ef eo ++oO @ a >o¢4*P °*.”¢+os A dare grey,hard,marttve,extroeanty fine grata te Alteration atnerals a >¢¢©¢©@ 4 cryptecrystalline storite contatning plaqtec tase.ineluse calcite,pyrtte,cry600-Prrezene,ang hernslenes crystals.weakly frectered |tseliaite,greee eley.a.ho +7 eo ©©©4 at 600 Ft,seme figPy-¢A black,hard,dente.extremely fine erate ts Alterstion minerals ee>e+©¢6 +4 ws eryptecrystalline giertte contarning plagioclase ane [ancluse pyrite and grey : _°¢©©I Diorite pyroxene crystals.eley.a=>¢*©f°4 °: co+©+6 ©@ -e aetu700er©©©a Py ie -¢©+eo oe 4 &qrey,hard,Gens,fine grain te cryptecrystaltine alteration winerats ® "+oe eo Giorite containing plagioclase,pyrexene,and We lude clay,pyrite,-warererarerers Rornelonce crystals,Fractured betwees calcite,epiaete,and° oo .¥#t,baoltatte.=.°ae o ed Ose rt 660 FC...and at 693 ft t po Ad &a °°.-¢¢@lJgooo4+6 ©+o &ae Q rar "+o?.. a :Cd o ¢+¢¢.A green,hard,Bignly fractured,sonanitic tqnewes alteration minerals"+oo Diorite Fock consisting of calette,cnlorite,and higaty Incluse calcite ane Getl+«««Dior Altered plagioclase.Possinle recrystaliizes famtt fcaterite,' oo *¢reese.;b 3o+¢A qreseish Grey,hard,enloritized,fine grate Only chlorite alteration.Leje¢©©©&@ Ciertte containing plagioclase,pyroxene,and900cmpmmmmmanmenmemamenmmnnanehermelendecrystals.Fractures from 866 ft.te ¢7 oe ©©+©©B76 Fe.and at 602 ft.eo,«-¢©©°°©4 A Vignt grey,hard,dense,sodium grain ciertte.Alteration winerals aeereeee4MignlyPracturedat929Ft.teclvee einer kseliatte,°quer °te °oe 0 +6 ee ane catcite ye oe +©oO 9 °e "ee ©©© «©&¢©©©©41,000 -ae-y ©¢©6 @ Oo 4 aee©©+© Y +©©©°soe,A qrey te cart green,hard,dense,fine qrate etartte |Alteration minerals aoeHL*+oo ©+e Diorite Containing plagteciase,pyresene,ane hernelense ine lude hastinste,clay,>.¢©ee crystals.Nignly fractured from 931 ft.o $47 FE.Prrita,caletts,eptdete eo*.*.*.eee 4 280 ft.=961 ft.,af 3,007 from 1,036 ft.-t.o%2 and cnlertte,a eo 2 4 45 4 4 ft...at 1,967 Ft.,at 1,088 ft.,from o1,100 45 1,063 #2.=1,068 FR.and at 1,083 fe,oe °-©©©++4 -co. -©©+©©+4 2 ¢©©©©©4 "1 ;200 .bd .*.*A *>°-«A Black,hard,spnanitie igneous reck;persthly iy ee ee oe rocrystallizes faslt quuge?e x1 ¢©©©©©©eit¢©©©©©€Pjorj .*%"of ©©©@ Diorite *-+©o oa +oo ©©oO ©«€ 1 3 fe)(0).J +>4 . *-7.©©8 8 °2 @ ©©©©@ 4 oe ef ©©©© Hye «©oe eo eo oo 4 A aare grey,hard,dense,fine grein ctorite Alteration preeuts are [Ct"er ©©©©@ containing plaqieciasse,pyrenene,and herasiousa quarts,-©©©©©©4 erystate.Fractures from 3,253 #t.«1,254 ft.ot enlorite,ané clay.oe eo eo +**4 Y.267 €R..rom 1,987 #¢.»1,283 Ft.5aramawamefree1,308 ft.©1,276 Ft.,at 1,400 $t.,at 1.088 ae1400 Y eo ©©©©©ft...Prom 1,467-Ft,o 1,672 ft.,end at 1,698 PE.'**©@ ©@ ©4 ie ¢©©©©@ 4€q oo ¢©©©@ @ oe a8 2+Le oe ««©««4Diorite % 2 **¢©©©©bad-¢©¢©©@ 4 3°oa cd .cd *<1,500 THIN SECTION LOCATIONS #Note:Q ©Quartz,Ca ©Caicite,=Encore,A=mnnvarite,P ©Pyrite,K *Kaounte,Cle Clay,Ce Chiorne,2 ©Zeoine,S ©Surfur &5 itAyyys,»aid Naeme te from core at icols) ioridd lens with crossed n ium grainehtlyalteredmediPhotomicrographofsligPHOTO11 5 x objectiveinTGH1-1.(2911ft. PHOTO 12:Photomicrograph of veins in diorite filled with quartz,anhydrite,calcite, =clay and chlorite from core at 1056 ft.in TGH J-1. (2.5 x objective lens with crossed nicols) UNALASKA ISLAND,ALASKA COMPLETION DATE: 9/8/82 'oe LOCATION:N 1,164,100 E 4,964,650 ° LITHOLOGY TEMPERATURE °C 0 20 40 60 80 100 120 140 160 180 200 ,T T T T TsaTat"Note:74.5 Hours between 9/15 &9/18 Readings. af .. Diorite N m4ys4 Diorita \am<Recr=Diorits 700 ooo ee oe I-1 GLACIER VALLEY DEPTH(FEET)©o 6 «©©©«©»|Diorite &T 250'-1500'=§.07°F/100°of f+©©+Diorite .°_7 Paneaeae ae aos ENVIROLAB TOOL -1050'-1500'=2.76°F/100° ¢¢*,°o *.°REY &Lew..1400° '500'=-1.98°F/100°rad era ae awa 9/15/8213100"ef ©©©© oo 6 ©&«©@ |Diorite ee7 7 .-hs |,.f 4 7?Leen shia (3 Cur nee fades Or YS:-7 from about 250 feet to =D.andap ears to be a relatively conductivesystemwithgradients.fe2.J°F/100-feet to 5.0°F/100 feet and a maximum;temperature of "79.°C (175.6°F)at 1,400 feet.The data in Figure 19 y»also shows that there is a small temperature reversal (2.3°C)over "last 100 feet of the hole.Th bal hye by arbi)it ne The overall temperature regime and profile of this hole indicates that the hole appears to be on the southern edge of the present a:geothermal system,at least for this depth range,although"the intensefracturingandmineralizationindicatesthepreviouspreseficeofahigh-temperature geothermal system.Definition of the boundaries of the present hydrothermal system was one of the uses and goals of the temperature gradient hole program.It appears that TGH I-1 was fortuitously located and that it achieved one of the major project objectives. A summary of the geochemical data for TGH I-1 is presented in ..Figure 20.As in the other holes,the general type of chemical anomaly .|4s the same.-The upper 700 feet of TGH I-1 contains several zones of.Hg,As,S,Li,and F enrichment,some of which correspond with one pee _another and some of which are isolated (Figure 20).Since the present temperature regime is considerably cooler than that implied by the geochemistry and there is large-scale artesian flow of cool water above 300 feet,indicating high permeability,the rock chip geochemtstry suggests the existence of a self-sealed zone in a paleo-geothermal .system that has since been refractured.re an E eae - we Geochemical analysis of the lower 800 feet of hole shows virtually ©no indication of past or present hydrothermal.systems,even though there.are old,healed fractures containing minor amounts of quartz,anhydrite and epidote.Thus,TGH I-1 appears to be located within the limits of an old geothermal system and on the edge or outside of the present . hydrothermal system. B.Aerial Photograph Interpretation On August 1,1982,two sets of stereo aerial photographs were taken.of the northwestern part of Unalaska Island,including the Makushin Volcano geothermal area.One set of color photographs,at a scale of approximately 1:24,000,and one set of black and white photographs,ata scale of approximately 1:36,000,were obtained by North Pacific Aerial Surveys of Anchorage as subcontractor to Republic.The quality of these photos is _ generally quite good,except for some areas of thin cloud cover,in the upperreachesofGlacierValleyonthecolorphotos.This is renarkableconsideringthevirtuallyconstantcloudcoveroverUnalaskaIsland. Using these photos,North Pacific constructed a 1 inch =2,000 feet scale contour map of the Makushin geothermal area.This map has been usedinportionsofthisreportasabaseforthegeologymap(Plate V)and forotherplates.- Lineament studies using 'the 'color photos resulted An the identificationofthelineamentsshownonPlateVEIL.All of the:-photos were utilized a:except those 'depicting primarily snow and/or clouds ,''and "those along the "trend.ee eastern-most flight line that were too far from the geothermal area. Approximately 520 lineaments are identified in the area. An azimuth frequency plot (Figure 21)of all ineaments identified onthecolorphotosshowsastrongeast-northeast to east-west trend in the -.'data,with a 'secondary northwest trend,and a weaker,northeast anomaly.Byfilteringoutlineamentslessthan'one-"half mile "tn length,a second azimuthafrequencyplot(Figure 22)again.shows the strongest trend,as ; east-northeast,with a secondary northwest maxima followed by the nor theast The east-northeast and east-west trending lineaments are dominantin the southeast near Captain's Bay,in the lower Makushin Valley,and northeast of _Sugarloaf Cone.Most of these are areas underlain by Unalaska Formation.The northwest-trending lineaments appear to be more evenly distributed. ,.FIGURE 20 ; DISTRIBUTION OF INDICATIVE GEOCHEMICAL ELEMENTS IN TEMPERATURE GRADIENT HOLE 1-1 . Hae Awe So Lie Fe Coy S102.Cus Mee Phe ond Zn Getne &Levees (G&L)ve Depth fer Rinpectte (WO0-feel)Cuttings ond Core Semples from Drill Hole I-1,Meunt Mokuchin Prespects Unelooks letend.Aleske.e PPB Hy oat PPM Ae Oa X 8 al PPM Le oat Pen F gat Co OAL K 8102 Oat PPM Ce BAL PPH He O6L PPr Pe ott .PPM Ie Gal>40.200,0 710.0 00-9 0 p.19 ee 0 po 2 10 100.400 0 _4-09 0 r 19:00 10,09 0 -100.200,0 2 LF o 7 204 0 -100.200, "or,mal §ay)®.vero F |[ats baa "13.®..I 3,|it J a ;if --"1k 1f ''fF ']a.49.3 'peg £».180. F ovis -.$0 |o38.ew of oY 2 2 2 2 2¢2k 2 2 "2 "aff | -15 18.3 +33 2 150.10 1.10 to 0.6.F ®. 4 LL a).3 3 a sf 3 3 3 3 oat.Tze |+18 3 2 F ato.i ptt 5 1.80 F ["38.,e.6.: e. af Lo af ak 4 ,|ce at 5 af at at 4 : |nm.nn.oe 3 2.Te |re 3 "10 -10.|"1 ]__"8. 5 Stl 5}sf 5 5 5 5} | 5 5|a.ay .120 F % ; 40.F as ;|-1.60 j "18.e.'@ ot. 6 8 sf of et ef }6 6 6 sf 144.med Ff 40 3 8.$0.|ces |:rT)"08.0.. F on, .7 ?t '7 rt nH Ut 1 ?rt "8.16.3 08 E te ry ;S i -.80 13."te :ae 6. U ef J *ofl 8 8 oa oer af ef I il of 8 "26.ae Ay)F a.|80.Ft 00 3 *4.350 ;20.®.:2.a. 4 .9 7 ate of Ue of a of 9 %9 of om.18.3 08 |rh 3 |90.ro:|[yoo 3 o3.10 1% 3 °:6."14s a vo LI 10 Ty TT:WOES og vo flrs te lof 10 o28.16.3 oe ET ry)ae SO Oe l 4000 RI "wo..Et.«£|-30.4 net "a uN NE ne ig Wee |nig 1 ne ont.et ee ==f 2400 .en 3 *4,00 ayy *.te F a ]F)tr)]Ts!vee AE ef 12}wet.Wak L,ara oar.of "01 i nD :sto.£ov |4.20 i o1.50 o33.E @.g 2 F 10 L 13 , 13 .3p 19El Soap oof os 13 13 wi Ll 3 e rr)00 ®o £2 1 ooo Te | 8.®.6.«. :14 14 vag oe eC:sat 14 14 vad 14 "16.]42.3 0s :@.+00.;'le 3 [+3.00 03.0.;a.|oeu1S15ists2UstisiLUrst.1s "gk Ub.13 . Meleot Depth oheen tn 100 foot entitle..@ Plotted veluse ave apperant geine &levees (Gil)colouleled by eublrecting =bechground valuce (feble 2)from ovtginel geochentoel dole (Appendin Ole 6)-.t lan iN (ACh COTS 123 270260980&i .f 15 ea %7 '.dp ay2Oe,.gs* :Oa,ont oat 125 The major gravity features are the low anomaly (15 mgal to 20 mgal)over Makushin Volcano,and the generally northeast-trending high anomaly -. (#10 mgal)centered over temperature gradient hole E-1l.The gravity high generally coincides with the outcrop and inferred subsurface distribution of the diorite mapped in that area.The transition zone between these twofeaturestrendsnortheasterlyandcoincideswiththenortheast-trendinglinearsandthesurfacealignmentofFumaroleFields#1,#2,#3,#4,and #8. D.Total Data Integration 2 The data gathered in the Makushin geothermal area lead to a number of conclusions: 1.The geologic mapping and lithology from the gradient holes indicate that the diorite unit is much more widespread than previously estimated and is likely to be the geothermal reservoir rock.The occurrence of numerous veins,fractures,and secondary minerals ._indicates that at one time (and possibly.at present)high -_temperature (150°C)|Fluids circulated_through |thee dtorite. 2.Surface manifestations (hot springs,fumaroles,and hydrothermally altered rocks)of the Makushin geothermal system encompass an area of approximately 70 to 80 square kilometers.This strongly -suggests an extensive heat source. 3.)Lineation studies from new aerial photography provide evidence ofpervasivefracturingofthedioriteandUnalaskaFormation.Thesefracturespotentiallyprovideporosity'and the permeability” -hecessary for the existence 'of a geothermal reservoir:The 'major" Vineaments have two major trends;the strongestis east-northeast : while the northwest trend is less well developed (Figure 22). ">present tectonic stress system since most of the faults mapped in the field,sca ertemarty in the younger Makushin Volcanies,have this -orventation.” A major trend that stands out,and is of interest with respect to the de Makushin geothermal.system,1s the set of =N40°E linears that extend from f just northwest of Fumarole Field #1 through Fumarole Field #8 past SugarloafConeintothelong,linear valley south of McLees Lake.This appears to be "the linear seen on the Landsat photo shown in the Phase IA Final Report that . is also close to the postulated alignment of Fumarole Fields #1,#2,#3,and #8.It is also closely aligned with the major trend of the gravity,as discussed in Stage VII.C. fo The majority of the easterly trending linears appear to-beFrelated totheUnalaskaFormationand/or plutonic rocks in the southeast'part of the area.This suggests that these may be the older set of fractures,joints, and faults.There are a few places where northeasterly trending lineaments are offset or cut by northwesterly lineaments.There are also a few locations where the opposite is the case.It may be that some northeasterly faults or fractures have been remobilized because of their inherent weakness.The nor thwest-striking lineaments are probably related to the | von The degree to nich these differing trends control the present or past geothermal systems is stil]unclear.However,the presence of such numerous lineations,representing faults,fractures,and joints,indicates that the rocks have been highly fractured and brittlely deformed,and it increases the potential for finding porosity and permeability in the Makushin7geothermalsystem. '€.Gravity Data The gravity map (Plate IX)presently available is a preliminary edition provided by J.Reeder of the DGGS.Although the stations are irregularly spaced and there may be uncertainties in the terrain corrections (J.Reeder, 1982,personal comm.),the map provides information that can be correlated with the other geologic data presented in this report. 10. The results of the multielement geochemical analysis of cuttings and core from the three temperature gradient holes indicate that the holes are dominated by a broadly occurring single type of ._ geochemical anomaly that is characterized by Li-F-As-S enrichments with or without Hg enrichment.This suggests that the hydrothermal rock alteration occurred primarily in a liquid environment under intermediate or alkaline pH conditions.The analyses also tentatively recognize possible hot water entry zones in TGH DO-1 andTGHE-1 that are surrounded by self-sealed or otherwi§impermeablezones.At TGH I-1,there appear to be fractured,'septoet sealed_rocks that permit lateral flow of thermal waters downslope from thefumarolesnorthandabovethesite.The geothermal resource in the area sampled by these holes js liquid-dominated with a temperature greater than 200°C.The potential for encountering the geothermal resource is greatest in the area of TGH E-1 and least in the area of TGH I-1. ) - albite,lower quartz concentrations,and a lack of kaolinite.The "younger"age alteration,which coincides with the present -.- geothermal system,consists of a dominant argillic type and a less prevalent propylitic type.Pyrophyllite,which occurs at FumaroleField#3 and #4 in the argillic alteration,only forms at high temperatures (>100°C).The propylite alteration surrounds only Fumarole Field #8 and suggests the geochemical characteristics of Fumarole Field #8 are different from other fumarole fields,*and that propylitization near the outer edge ¢of the>geothermal system |is in progress. Geological studies of surface diorite outcrops and of dtorite coresshowthatnumerousnear-vertical fractures exist.The fractures represent joints that occur on a 0.3-meter to 2.5-meter pattern )The X-ray diffraction analysis of 13 "hydrothermaty alteredfetta-suggests that two episodes of alteration occurred in the Makushin:ae"geothermal area.The."older*stage contains a higher percentage of ) The mercury soil survey identified high background values of mercury and several highly anomalous areas that trend northeasterlyalong-a line connecting Fumarole Fields #1,#2,#3,and #8 (Plate III).These extremely high mercury concentrations suggest the Makushin geothermal system is a fractured,high temperature (>180°C)hydrothermal system. , The self-potential (S-P)survey outlined two anomalous areas within the Makushin geothermal area.There is also an elongated S-P low that trends northeast and that overlies the manifestation trend(Plate IV).The S-P survey is interpreted to indicate high temperatures and/or fluid movement along this trend and in the Fox Canyon area where it coincides with the mercury anomaly. The gravity data supports the wider distribution of the diorite and the evidence of a northeast-striking structure that extends from Glacier Valley to Driftwood Bay valley.Field geology,which'discerns no"noticeable Faulting or disruption 'of the stratigraphyalongthisinferrednortheaststructure,-'suggests that the.structure is an older subsurface feature that appears to have beenremobilized.However,it does appear to exert control over the surface distribution of a major portion of the present hydrothermal system.eeThermalinformation(gradients and temperdures obtained from the gradient holes)proves that subsurface emperatures in the Makushingeothermalsystemarehighenough"(383°F)to generate electricitycommercially...The data indicate that-TGH E-1 has the highest temperature at any constant elevation above sea level,although/commercial temperatures could also be reached at site D if a well were to be drilled to 3,000+feet. 13/Chemical composition of the Makushin thermal waters indicates the/chlor ide-poor waters form by mixing of ground waters and steam|accompanied by hot:gases.The larger Cl,Na,K,Li and B values of Tos/'the chloride-rich thermal waters'show that a high-temperature watercomponentexistsinthesewaters,although their relative concen-(¥t ,trations and additional tons confirm that mixing with ground:water.(-rlvwes/has occurred.The presence of these two classes suggests that a ©Ae tated |\liquid-dominated reservoir overlain by a steam cap exists in the., >\rakusntn geothermal area." ,1 f ..fF s15.A mixing model geothermometer predicts a 294°C subsurface tempera - otrwretureintheliquid-dominated reservoir.Gas geothermometry (Motyka Came a'td et al.,1983)estimates a 297°C reservoir temperature.why Ne fede Von ct dina ad Co op WeaAwa,Wuthen ;"e Topln hs fay domes te dees dys16,Stable isotopes of the Makushin waters plot near'the meteoric water Tiny,tehlineexceptforthehightemperature,steam condensate samples.The (40°Cchloride-rich waters have a slight 3!89 shift that,when combined_with the steam condensate isotope values,estimate nearly the same |areservoirtemperature.as.the above geothermometers.A11 stable foes'isotope analyses confirm that meteoricwaters from Makushin --- Volcano's flanks charge the liquid-dominated geothermal reservoir. (1.»Maxing.ratios estimated via the stable isotopes and silica--enthalpy fout)KO.Aea\\t *\technique predict that the reservoir's water is similar in 'chemical an<composition ( 7000)ng/TDS)"Eo ROSSEVETE'Hot Springs,Utah,a xteeaaacommercialgeothermalsystemthatissituatedinagraniticrock|reservoir at approximately the same temperature as 1s estimated fortheMakushingeothermalresource,:"ys 7 Soe time =a id .a_Cee net cot :.re ees_ye ,18."Temperature gradient «data reveal that TCH'I-1 4s situated at the:a |southern boundary of the Makushin geothermal system.The &ints .conductive and convective nature of TGH I-1's gradient voftie\vit 'Andicates several thermal aquifers were penetrated during drilling:Ay ° ._AN of TGH I-1].The isothermal profiles followed by a temperaturewy5\cuf A P\Wy -atlalidy lmdicdion Sy Ning Vi. vd pare yy! \phegess° and/or along tectonically produced ruptures.Lineament maps and field observations suggest that the regional fractures are orientedeast-northeast,northwest,and northeast. Geological relationships show that widespread recent (post-glacial) volcanism has occurred in the Makushin Volcano region.This '4s supported by the reported 14 historical eruptions of Makushin "Volcano (Sean,1980).Recent volcanism has also occurred to the. northeast of Makushin Volcano at Widebay Cone,Tabletép,Mountain,Cinder Dome,and Sugarloaf Cone.Even though Tabletop Mountain and-Z Widebay Cone originated from a separate magmatic source than the _Makushin Volcanics (Reeder and Langmuir,1982,pers.comm.)},theiryoungageimpliesanorthandeastextensionoftheMakushin Volcano heat source,a separate magma source,or a source situated -between the two that differentiates to produce the resulting | differences.Sugar loaf Cone,and the dominance of recent volcanics'on Makushin Volcano's eastern flank,suggest that-'the magma trendseastwardfromthesummitcraterofMakushinVolcano.>Spt liefosLidtey{ev lws dy hd fe Mean -8 CRAY"Structural features in the vocushin Volcano geothermal area are dominated by faults that trend east-northeast,northwest,and northeast.Additionally,the surface geologic map of the Makushin geothermal area (Plate II)shows three faults trending northwest "and a fault striking north-south.The alignment of Fumarole Fields 13. #3,#4,#5,and #23 suggests that.a hidden structure oriented _east-west may localize these fields. Chemical analysis shows that both a chloride-poor and a .chloride-richclass of thermal water exist in the Makushin'®Geothermal Area:The chloride-poor group,which 4s a calcium sulfate type water,usually occurs near fumaroles.The chloride-rich group waters are found in both Glacier Valley and Driftwood Bay valley away from the fumaroles and at lower elevations. | / o . 2are increase and then reversal at T.D0.in TGH I-1 confirms that the C3aquifersaretransmittingthermalwaterdownslopefromtheirpoint "4 .4 'if . 'of mane fh ](J \ibs clyde |t!re wv)flaps 4) \ve ee os 0 dette)ads Inusin bovta fd,E-1,'. fA_19.thermat (dattatin TGHtee ireveal that the geothermal reservoir isQLapparentlyffset>Yo tthe east of Makushin Volcano!s summit..ee oA ASNBe eth ce)by ford rdLieslAtvalsWhe haInsummary,the aggregate evidence collected to date indicates the -presence of a widespread (70 to 80 square kilometers),conmerc}a]temperature (195°C+)geothermal system.The system is probably water-dominated with a steam cap that may vary in thickness and extent. There appears to be enough fracturing present in the rocks to support a reservoir large enough for commercial electricity production.However,this can be verified only by deep drilling and testing. v7 E.Geothermal Resource Model Refinement II The model of the”"Makushin geothermal system that best iMustrates the -_€&"system as it appears on the basis of current interpretations:is depicted on "aFigure23,which are north-south and east-west geologic cross sections - through the Makushin hydrothermal system.This figure includes temperature isotherms that are overlain on the geology.The proposed model of the Makushin geothermal system possesses the three common components required in all commercial geothermal systems:1)a heat source;2)porous,permeable reservoir rock;and 3)fluid for transporting energy (water or steam). The heat source of the Makushin geothermal system appears to bea buried ; igneous intrusion that may be associated with the Makushin volcanic suite.The uneroded summit crater of Makushin Volcano,the glacially carved valleysfilledwithpyroclasticflows,and the construction of Sugar loaf Cone on top of post-glacial pyroclastic rocks al]indicate that the heat source was still molten after the last glacial period [approximately 3000-4000 y.b.p. (Black,1975)].The 14 historical eruptions of Makushin Volcano suggest that molten or semi-molten rock is currently likely to exist beneath CMakushinVolcano.,: ae ee: .i.mbes1hiIs iy posh"pps A .wfhorteewedelletCwtieswall- vadliptdsadThemechanismforenthalpy|transfer from the intrusion to the geothermal (i:reservoir is dominated by conductive heat Flow.This is implied because Ne ars .a "neither the stable-isotopes:-of..the 'thermal waters,nor the stable isotope L a)putofsteamfromMakushin's summit,nor the carbon isotopes of.Fumarovic "Une i }ae Wl by (%an methanéshow "magmatic”Signature (1.e.,one that would be caused by . - -¢onvection into the reservoir of magmatic fluids)..Vhs - | ¢:Argos Q It appears that the heat source is not directly beneath the summit and.that it is offset asymmetrically to the east.Two lines of evidence are;isha?PL"?diagnostic:1)the.dominance of post-glacial Makushin volcanics,including Pupathnidi.Sugarloaf Cone,.on the eastern flanks of Makushin Volcano;and 2)the high ft,Kalan s temperatures:that were measured in TGH E-1,as compared to those in TGH D-1 'Vids e"at any given_elevation,which fact(Fequires Yat the heat source be closer 5 to TGH E-1 (more easterly)than to TGH D-1.stmt tar offset of the heatsourcefromthecentralsurfacevolcanicventhasbeendocumentedatCer 1\ete,teres at Tiwi,Philippines;and at Matsuksaee-3a io accmege) ;Dentin f hdss ft!fre dey tint |we /-a oa The Makushin geothermal reservoir is.situated primarily within the sane s .Makushin dioritic stock at commercially exploitable depths."However,it.'is oh etsno"possible that beneath andto the west of Makushin Volcano's summit crater aceDe,"reservoir.may exist within Makushin Volcanics or 'Unalaska Formation.The occurrence of most of the surface geothermal manifestations within diorite . outcrops,the high,conductive temperature profiles recorded in the diorite, and the elevated observed temperatures are all evidence for a diorite _-reservoir.An impermeable seal for the reservoir is comprised of clayeyalteredbasaltmembersofthecappingvolcanicrocks,as seen in TGH D-1,and by chemical precipitates.which have "self-sealed"the diorite,as seen Be"An TGH E-l.7 cS .ce ,perente eae Sg /Reservoir permeability and porosity relies predominantly upon -theexistenceofopen,high-angle (>45°)to vertical fractures.The fractures follow joint patterns inherent in the rock and ruptures produced by regional: tectonic stresses,as observed in outcrops and in cores.The major joint and fracture orientations,discerned from air photo analysis,are Notes on paragraph two,pg.132. "¢ The data may suggest your conclusion that E-l1 is horizontally closer to the heat source,but I disagree that it requires it. 1) 2) 3) 4) The elevation of D-1 is 600 ft.higher that E-l,and this must be taken r " into account., Isothermal conditions ( 10°C)prevail to a depth of nearly 800 ft.at D-l1,presumably as a result of cold water circulation in vertical frac- tures.Similar temperatures extend to depths of only 100 ft.at E-l.. The 10°C temperature boundary is therefore at a much greater depth in D-1l than at E-l1.The location of the cold water temperature boundary and the rock type are conditions which influence the temperature profile.Any comparison must take these factors into account.--' The thermal regimes in the two holes are distinctly different.The «temperature profile in D-l appears to be predominately controlled by convection while most of the E-1 profile indicates conductive heat transfer.These differing heat transfer mechanisms must also be taken into account. Temperature profiles can be readily modified by convection of hotter or colder waters.Such convection can easily mask the presence (or non- presence)of a heat source. sie an BB ,FIGURE 23. GEOLOGIC CROSS SECTIONS.DEPICTING THE MODEL OFTHEMAKUSHINGEOTHERMALAREA(nA"CROSS SECTION SOUTH FUMAROLE #3 »7FUMAROLE #2 NORTH 4,000 --"THE PASS”. 'GLACIER VALLEY ae --4.000 13,000 --°D-1 --3,000 FEETNOo°of=)m™m1_Aaaevfa>,Nfo]oeOoFEETraw}ee artFettvOeSSS -++++++++t++++++ + ' +++++++++++++++&+4%'SCALEtfetitttteeteeettttteeeeineNIx)9100°C 150°C 200 Cc 0 2,000 4,000 FEET EAST |oa WEST ce}-_R'a eet >5,000 -- B-B'CROSS SECTION :D-1 PROJECTED -5,000 tSOUTHZ |=MAKUSHIN PYROCLASTICS4,000 ---. : :--4,000 va very . be :3.000 effetarr YOUNGER MAKUSHIN VOL _IC!wi 3,000--000 Ge S$F<)OLDER MAKUSHIN VOLCANICS 2,000--- >.---2,009 uw OP rare *MAKUSHIN DIORITE1,000 ---009 &¢Wit!UNALASKA FORMATION, ++++++4 eee meen.X iw ++++6 +++; + ++++++++ otf +4,.%+++++++*S oe *0%0 +n +&.a 4 'o.avonaeedho \:-SCALE .NORTHEAST FRACTURE ZONE ©. -Q 2,000 4,000 FEET act C97) aepeseast-northeast,northwest,and northeast.The northeasterly trending fractures reflect remobilization of older faults,while the fractures withotherorientationsmaybeduetounderthrustingofthePacificPlatebeneath Unalaska Island. * The location of the Makushin geothermal reservoir appears to be struc- turally controlled by a major northeasterly striking fracture zone.This zone 1Sa long,wide,older,highly tectonized feature whose inherent weak- ness probably played a major role in the intrusion of the original diorite stock.The fine-grained texture of the diorite suggests shallow,relatively rapid intrusion followed by a short crystallization period that produced the.closely spaced joints observed in outcrops.This structural zone has been refractured at least twice since the initial dioritic intrusion,as shown by several sequences of vein-filling minerals and as reported in the three gradient holes.More recent movement along this northeastern-trending zone maintains the permeability of the fractures in the present-day geothermal reservoir,and the ruptures in the impermeable cap along which the majority -of.the surface geothermal manifestations (Furiarole Fields #3,#2,#,BooseHotSpringsGroups#20,au,#12,#8,"#10;and the.hidden Driftwood BayPLEttakSoeaeaaheyyevalleythermalwaters)occur.The gravity data and the mercury soil anoma-alieshelpconfirmthepositionéandextentofthenortheasterTytrendingfracturezone. There are two subparallel structures which intersect the northeastern- trending zone and which may extend the Makushin geothermal reservoir.A hidden east-west striking fracture zone may expand the reservoir beneath iFumaroleFields#3,#4,#5,and #23,and a nor thwestern-trending fracture.onwSoe gee ttthesouthedgeofFoxCanyonmayextendthereservoirtowardsFumaroleField7 #7.oh -*co ro on So ete Jae Wal |a Utilizing this model,the commercially exploitable reservoir in the Makushin geothermal area may cover approximately 40 square kilometers.The reservoir.appears likely to be confined to an approximately three-kilometer-wide zone trending-northeast from Glacier Valley to Driftwood Bay valley, with minor lobes extending beneath Fumarole Fields #3,#4,and #5 and Fumarole Field #7.: TABLE 13 ROOSEVELT HOT SPRINGS KGRA,UTAH_GEOTHERMAL.jRESERVOIR FLUID (BAMFORD et al.,1980) = TDS 7000 mg/1 / cl 3500 mg/1- Na 2437 mg/1 $10,260 mg/1ee Lowfee Be"iSincethereservoirfluidsappeartoberelativelyfreshtsZe,"000 onppm)thereis,"apparently,no intrusion of seawater into the syste and recharge is provided by rain and snowmelt water percolating downward,primarily through the volcanic rocks.This condition is similar to that found in the Hawaiian HGP-A geothermal well. : So.In summary,the 'Makushin geothermal system appears to be a eeVyquid-dominated resource situated in fractured:didrite within a onfortheasterlytrendingzonethathasminorlobesextendingwestwardonits esouthwesternandnortheasternends.Reservoir waters rising upward (convecting)boil below an elevation of 1,200 feet in localized open fractures to form a steam cap that is limited in size and extent.Leakage of steam from this cap feeds the fumarolesand mixes with ground waters to form the chloride- poor thermal waters.Reservoir waters appear to be mixing-with ground waters before exiting in Glacier Valley and Driftwood 'Bay,valleys as chlor ide-rich hot springs,and An Glacier Valley”as feed stock |for the numer ous halite occurrences. aAlthoughthisrefined geologic model of the hydrothermal system 4s a considerable improvement over the initial model,there are still some unanswered questions and unproven hypotheses that can only be resolved by deep drilling and production tests./a | "oh The Makushin geothermal resource consists of a liquid-dominated ,Cxreservoirwithasteamcapthatvariesinthicknessandlocation.The chloride-rich-type thermal waters in Glacier Valley and Driftwood Bay valleys,and the numerous occurrences of halite (Motyka,personal comm. 1983)in Glacier Valley,are evidence for a hot-water reservoir.The geochemistry of the cuttings from the gradient holes also supports a: liquid-dominated reservoir.The local existence of fumarolic activity and of chloride-poor thermal waters imply that a steam cap overlies the a" hot-water reservoir.Unfortunately,this vapor zone does not appear to be ubiquitous,as seen in the temperature gradient holes,but appears to be limited to areas beneath the active fumaroles where open fractures permit boiling.It is also implicit that the steam-liquid interface,when it exists,is below 1,200 feet above sea level,the lowest elevation of steam vents in Fumarole Fields #1 and #3.cprk Ih)Buaatel er.wip ldCalculationsutilizingfourgeochemicalgeothermometerssuggest ee thesubsurfacegeothermalreservoirtemperatureexceeds200°C.wdsupportedbythe193°C static temperature measured An TGH.E-1.©The . geochemical signatures of the core recovered from TGH E-1 'Amply a Fluid -temperature greater than 200°C;the silica-enthalpy mixing:modelgeothermometer(Fournier and Truesdell,1974)predicts a 294°C reservoir. temperature;the gas ratios in the superheated steam of Fumarole Field #3 suggest a 297°C subsurface temperature;-and'stable isotope values in the chloride-rich waters,compared to the superheated steam,indicate a resourcetemperatureofapproximately290°C.;Le baad aed che.ethan 2ne---ey ene neseternaaLn Stable isotope concentrations reveal that meteoric waters originating onthe.flanks.of Makushin Volcano recharge the reservoir.Mixing ratios mo"derived from the stable isotopes.suggest”that-the-reservoir-fluid-chemtstry is similar to that at Roosevelt Hot Springs,Utah (Table 13),where a 275°C liquid-dominated geothermal resource 4s contained in a granitic reservoir. am wok v iQ wyis subparallel to the main northeast lineation,and they may provide evidence of enhanced fracture permeability in the vicinityofthe"Base Camp"and "Fox Canyon"target areas. 4.The geology,geophysics,geochemistry,and thermal data discussed above all suggest that these areas appear to overlie a commercial geothermal resource at shallow depths. ! 5.The "Fox Canyon"and "Base Camp"target areas both permit reasonable access in terms of wind,weather,maneuvering space,and level work areas;although,the "Base Camp"target area has the best overall conditions.Therefore,the "Fox Canyon"and the "Base - Camp"target areas seem to be the best areas for the first deep exploratory well,based on both the refined resource model and -logistical considerations. _G.Deep Welll Site Selection a : , .es vee acre tote .wii hy Pope cee Steerscede-an ..cr .Rat aeomTeesaceSheaeSoan os"Two specific 'deep well aril sttes have been chosen within each 'of theoSCanyon"and "Base Camp*target'areas as shown in Plate VII.'The "Fox!: Canyon"No.1 site is approximately 800 feet east of the D-1 hole location. The site was chosen becauseit is considerably more level than is the. terrain at TGH D-1 and it eliminates having to drill through 40 Feet ofboulder-rich glacial till that was penetrated in TGH D-1. "Fox Canyon"No.2 site,about 2,000 feet north of TGH D-1,1s considered to be the most accessible siteif a road from Driftwood Bay or. Broad Bay to the site was to be built.However,since the cost of building. such a road was determined to be prohibitive compared to access vials”helicopter (see Appendix B),this well location is:considered to bef: secondary to "Fox Canyon"No.1 site. a F.Resource "Target"Identification CYThe geothermal resource model described above has been used to identify the three target areas considered to be most prospective fora deep (2,000° feet to 6,000 feet)exploratory well. Plate VII shows the locations of these three areas.The first, designated as the "upper Glacier Valley"area,in the vicinity of FumaroleField#3,has strong potential in light of the superheated stedm that is-being emitted from Fumarole Field #3.However,access is ferfFavervean duetopersistentheavyfogandclouds,prevalent high winds,and minimal space for helicopter maneuvering.Also,it is near the apparent edge of the hydrothermal system as defined by TGH I-1.Logistics and accessibility are overwhelmingly negative factors that preclude the selection of this site for «+ "the initial deep well. The second and third targets under consideration are designated as the ©"Base Camp"and the "Fox Canyon"areas (Plate VI),These locations have oe @}3beenchosenonthefollowingbases:. 1.The plateau near the base camp and TGH E-1 are on the northeast-trending structure defined by the gravity,S-P,and mercury surveys,the air photo-satellite lineations,and the alignment of the surface manifestations.. 2.Temperatures measured in TGH E-1 at 1,500 feet (195°C)are considered high enough to generate electricity,and thetemperaturesandgradientsinTGH0-1 (Fox Canyon area)suggest that commercial temperatures would be encountered at reasonablyshallowdepths(2,500 feet to 3,000 feet): 3.Both the "Base Camp"and the "Fox Canyon"target areas bracket two areas of steaming ground that are aligned in a northeast direction (Plate I).These manifestations may be emanating from a zone that C: saeSF;sonyreservoir parameters (temperature,fluid chemistry,flow rates,pressure drawdown,and productivity index).This type well would be a permanent producer and was specifically requested in the original Request for Pro- posals from the Alaska Power Authority that initiated this contract.TAprogramfordrillingacommercialsizewellisincludedasAppendixK-1. Experience acquired during the 1982 drilling season made it clear that this type of well would require a rotary rig with a drilling capacity of at least 6,000 feet.Use of that type of rig would cost considerably more than "estimated in the original project budget.A single 6,000-fdot'deep production-sizewell would cost an estimated $6,000,000,primarily due to the costs of rig mobilization and demobilization,and the transportation of an adequate stock of contingency supplies and equipment.Since approxi- mately $2,700,000 remains in the project budget,one production-size well would require additional funding in excess of $3,000,000,a sum which is apparently unavailable for the upcoming drilling season._ a"Option #2 4s toGrii1a small-dtaneter (2-1/2-inch diameter at T.D.)25.0577.**exploratory well to about.4,000 feet using.a much 'smaller coring.rig.°ThisSe"program would utilize a Longyear 44 (or equivalent)wireline diamond core: drill similar to the Longyear 38 used for drilling the temperature gradient. holes in 1982.Although the depth capacity of this rig is roughly twicethatoftherigusedin1982,the mobilization,demobt lization,and'operating costs are.only slightly higher.- A smaii-diameter exploratory well could yield approximately 15 percent -)to 80 percent of the data that could be acquired by testing a production-"size wel](temperature,pressure,fluid composition,and limited drawdown sett7information).However,such a well”would not be capable of commercial”production rates and it would,at best,provide only minimum reservoir.productivity data..:ones 139 The "Base Camp"No.1 deep well site is about 1,000 feet north of TGH E-1.This location features a large,level working area plus proximity to Fumarole Field #1 and to the steaming ground in Fox Canyon.'The "Base Camp"No.2 site is essentially at the same location as TGHE-1,where temperatures are known to be 193°C at 1,485 feet.Both these sites lle on the major northeast-trending zone. All of the sites have relatively equal geothermal potential,except - that:a)commercial temperatures have already been encountered in the "Base Camp"area;and b)the "Fox Canyon"No.2 site is slightly removed from the main anomalies to accommodate road access.Therefore,selection of the prime site for the first exploratory well from the alternative sites described above 1s strongly influenced by logistics and weather patterns (the sites are essentially indistinguishable from an environmental perspective).In this regard,drilling problems at the Base Camp sites are minimized because of the absence of volcanic rocks overlying the diorite. Additionally,the "Fox Canyon"area has considerably more fog and unstable"wind conditions than™the "Base Camp"area.Many times during the 1982 field 7 eS"season”access to the "Fox Canyon"area was delayed due to low clouds or fog,while the "Base Camp"area was relatively clear and accessible by helicopter. On the basis of the superior weather conditions,the known high temperatures,the lack of thick Makushin volcanic rocks,and the large, level working space,the "Base Camp"No.1 site has been chosen as the location for the first deep exploratory well. H.Oeep Exploratory Well Drilling Program - Having selected the optimum site for the deep exploratory well,there are two basic options regarding the type of well to be drilled. The preferred choice is a production-size exploratory well designed to be capable of producing commercial quantities of geothermal fluids. Flow-testing such a well would allow the determination of all the required C. 138 I.Preliminary Deep Well Testing Program Since it appears that the first deep exploratory well willbe a small-diameter well,as described above under Option #2,the Followingwell-testing program is proposed. As soon as the well is completed,and while the drill rig is sti11 on location,the well]will be flowed into the mud pit or other containers for a few hours to:1)clean out any loose cuttings,mud,etc.;2)determine the type of resource encountered (dry steam or hot water);and 3)obtaina sample of the reservoir fluid for chemical analysis.The analysis is likely, to be a condition of any permit to discharge geothermal water into the Makushin Valley river (see Stage VIII.A.and Stage VIII.C.). Once the resource type and the ability of the well 'to flow have beendetermined,and the fluid sample(s)have been acquired,the well will be 'shut--in and the drivi tig moved to the temperature gradient hole location or.a demobilized to Dutch Harbor.A Republic production or facilities engineer "and a technician will then be mobilized to the location 'to begin.ols"construction of the required testing factlities.This activity wilt occur while the fluid samples are being analyzed and actual permission to discharge is being obtained.Once the actual test begins,a Republic geochemist and reservoir engineer will be onsite to oversee careful| 'collection of pressure/rate/temperature data and geochemical samples. Depending on the resource type (steam or iquid-dominated),one of the following test programs will be followed.In either case,the test Asintendedtoachievestabilizedwellproducingconditions,'at one or more flow rates,for the purposes of measuring well and reservoir Performance and sampling the produced fluids. 141. a _production wells.In.the future,it would be highly cost effective to plan The estimated cost for this type well ts $1,750,000,including testing (. and Republic's costs and fees.If the small-diameter well costs stay within the estimate,there would be adequate time and funding available to drill a fourth 1,500-foot to 2,000-foot deep temperature gradient hole near ° Sugarloaf Cone.Such a gradient hole would provide additional vemerdture distribution,geochemical and geological data regarding the extent of the resource at an incremental cost of approximately $500,000.The totalprojectcostsfordrillingthetwoadditionalholesdescribedunderOption#2 is estimated at $2,450,000,still well under the remaining 2,700,000-budgeted.Drilling programs for the deep small-diameter wet]fad the new gradient hole are included as Appendix K-2.} At this point,Republic believes that proceeding under Option #2 is in the best interests of the Alaska Power Authority for the 1983 drilling : season.If the deep small-diameter well is successful in encountering a commercial geothermal resource (as we suspect it will be),the knowledge-_gained will allow the development of firm plans for the drilling of "on drilling several large-scale wells in one season,thereby minimizingmobilizationanddemobilizationcostsbyamortizingthesecostsovermore than one well. -; The drilling of a small-diameter well to 4,000+feet will eliminate the need for much contingency planning that would be required for a future full-scale production well,given the information presently available. _These uncertainties include optimum sizing of the rig (based on a firm total depth),optimum drilling fluids program,specific required quantities and,grades of casing,and surface fluid handling facilities based on resource type and properties,etc. -- Appendix K-1 contains a preliminary program for the drilling of an Option #1 6 ,000+-foot full-sized exploratory well which would be completed as a field producer.Appendix K-2 contains programs for the drilling of a both 4,000+-foot small-diameter exploratory well and an additional C1,500-foot to 1,200-foot temperature gradient hole (Option #2).* EENDuring the flow test,steam would be discharged to the atmosphere.Little or no water would be produced.The actual flowtestisexpected:to last approximately three days.A total of four more days will be required to install and to dismantle the test facility. Hot Water Resource Assuming that the resource is liquid-dominated (which3s currentlyexpected),the following data are normally obtained in conjunctionwiththetest: a.Downhole pressures and temperatures obtained by using Amerada-type wireline instruments,including: i.Downhole pressure and temperature surveys under stabTe static.conditions before and after tthe flow testson 11.Downhole pressure and temperature surveys under stableFlowingconditions(to be repeated at more than one flow rate if possible);and 111.Downhole transient pressure response to step rate - changes (if any)and to the final shut-in at end of flow )test; b.Wellhead pressure and temperature obtained under Flowing andshut-in conditions;.:=.0%fay Paes So wie eae a acc.Flow rate:"as measured by the "modified James method"or+by the"separator-weir"method: d.Noncondensable gas content of the steam (qualitative and semi-quantitative)if facilities permit gas collection;- e.Geochemical samples of produced geothermal water; Dry Steam Resource G If the.resource encountered is-'dry steam,the well testing 1s . fairly straightforward.It is not necessary to handle large volumes of water,and the resource flow is ina single phase so that flow rate measurement is relatively simple.The test will be monitored for well and reservoir performance data necessary for a preliminary evaluation of the resource.Such data normally include the following: . a.Downhole pressures and temperatures obtained by using Amerada-type wireline instruments,including: 1.Downhole pressure and temperature surveys under stable .Static conditions before and after the flow test; Vi.Downhole pressure and temperature surveys under stable"Flowing conditions (to be repeated at |more than one "..Beflowrateifpossible):ee RR Wie Downhole transtent pressure response to step-rate changes (if any)and to the final shut-in at end of flow test; b.Wellhead pressure and temperature obtained under flowing and shut-in conditions; . c.Flow rates as measured by a standard orifice meter;->°°" a ad.Noncondensable gas content of the steam (qualitative «and semi-quantitative); e.Geochemical samples of steam condensate and noncondensable gases..e 1a? $50,000 for the testing program described above.Helicopter,camp, communication,and other ongoing project charges are not included in these cost estimates.7 : 3.Deep Well Budget and Scheduling In light of present project funding uncertainties,budgets for two 1983 drilling programs have been developed.The preliminary budgets and a schedules for the two options are presenteditn Appendices L-1 and L-2. Option #1 (Appendix L-1)is for a 6000+-foot large-diameter production well.Option #2 (Appendix L-2)applies to a program consisting of the drilling of a 4000-foot small-diameter exploratory well "slim hole"and a 2000-foot temperature gradient hole. VAT * o This flow test is expected to last about seven days,depending on the time necessary for the flow rate(s)to stabilize,with an additional total of,four to five days required to install and . dismantle the test equipment.During the test,the produced |liquids will be allowed to flow into tributaries of the Makushin Valley river if the initial chemical analysis from the clean-out flow test indicates that the fluids are not hazardous and'a permit has been obtained. £.Once the onsite testing has been completed,all the tt data will be reduced and interpreted so that a preliminary resource evaluation can be submitted as part of the Phase II final report. The primary results of the evaluation will include physical and chemical characterization of the resource,estimates of potential full-size well deliverability and possible scaling or corrosion problems,and data to facilitate preliminary power conversion cycledesign. a ae Preliminary Well Test.Cost Estimates)3. Estimated costs of Republic labor for the testing phase include the services of a geochemist,a production or facilities engineer,a reservoir engineer,and a technician for a total of 47 man-days ($28,000).This includes overhead and fees which are pro rata amounts based on the small-diameter well project as a whole.It does not include the costs of data synthesis and report preparation "Equipment rentals,supplies,and Non-Repubtic labor"include suchitemsaswirelineequipmentanddownholeinstruments;pressure,temperature,and flow rate instrumentation at the surface;surface f low equipment;sampling expendables;instrument calibration;: transportation;and compressor rental or nitrogen bottles if . necessary to initiate well flow.These charges are estimated to be 144 STAGE VIII -DEEP WELL PERMIT ACQUISITION _.»A.Fluid Disposal Methods< Should the Makushin Volcano resource encountered by the small-diameter resource confirmation well prove to be dry steam,testing of the well will be direct to the atmosphere and produce essentially no waste geothermal liquids. However,should the resource be primarily a liquid,disposal of a potentially significant quantity of waste geothermal liquids must be accomplished inatechnicallyfeasible,cost-effective,and environmentally sound manner.Anumberofpotentiallyviableoptionsfordisposingofthiswastegeothermal liquid have been evaluated,with the recommendation that the liquid be discharged into tributaries of the river in Makushin Valley. Generally,disposal of these waste geothermal liquids can be accomplished eitherby returning the liquids to the geothermal reservoir via subsurface_injection,or by discharging the Vquids to the land or surface waters.Aosfumberofpotential"alternatives are available For each option.aoei 25 pando:a ae eeesubsurfaceinjectionofthewasteLiquids'could be accomplished 'through | use of the small-diameter resource confirmation well,one of the existing temperature gradient holes (TGH's)or a new Injection well specificallydriedforthatpurpose. A new well drilled 'specifically for the purpose of injecting the waste "geothermal liquids produced from testing the small-diameter resourceconfirmationwellwouldbebothaverycostlyandtime-consuming project.|For these reasons,it 1s not considered a reasonable:'option,although itmayberequiredinthefutureshouldthedevelopmentoftheresourceprogressto ;_the stage of long-term,high-volume well flow tests,or to actual utilization.- Conversion of one of the existing TGH's to a temporary waste geothermal liquid disposal well would also be a costly and time-consuming operation, -.although probably not quite as much so as a new injection well.Ata a Vth 89we Direct discharge of the waste geothermal fluids to the ground is a very low-cost disposal technique which has been used frequently in the other geothermal projects,particularly in arid regions where surface waters and vegetation are scarce and,therefore,are unlikely to be significantly impacted by the discharge..However,discharge of geothermal fluids to the ground in an area such as Unalaska,with abundant surface waters and steep, erodible slopes,would very likely bring significant sediment into the rivers,degrading water quality and adversely impacting the important freshwaterfisheryresources.i 2?As an alternative to the above,direct discharge of the Aste geothermal liquid into tributaries of the Makushin Valley river would significantly reduce the sediment load introduced into the surface waters of Unalaska Island from the test.However,tt could increase the impacts to the river due to elevated temperatures.To minimize this temperature problem,the waste liquids could be cooled prior to discharge by short-term storage onsite in tanks or by spraying the liquid out over the tributary and allowing it tofallasalightmist.Degradation of the river!s water quality.(and.thus .Impact,on the river's fishery.resources)would then''be only a function of the.2%river's ability to dilute the salts introduced by the waste 'geothermal Fluids. The impacts of direct discharge of the waste geothermal liquids to tribu-taries of the Makushin Valley river are expected to be negligible because ofthefollowing:the expected flow from the small-diameter resource confir-- mation well is small (0.09 cfs);the expected salinity of the geothermal _fesource is moderate (10,000 mg/1);the fishery resource of greatest concern (pink salmon)has been observed no closer than 3 miles downstream from the,anticipated discharge point;and the Makushtn Valley river 1s expected tohaveahighflowrate(about 270 cfs)at the point of potential First "{mpact |to the pink salmon at "the expected time of discharge.Discussion with the appropriate regulatory agencies regarding this option indicates that they will likely approve the proposal.Since this disposal option is low in cost, probably Tow in environmental impact,and technically feasible,4t is the recommended option. minimum,a coring rig would have to be set up on the hole and the tubing C: pulled out of the.hole or perforated.The technical feasibility of eitheroperationisnotcertain.In addition,the geological feasibility of such aconversionoperationisnotcertainsincetheTGHmaynothaveencountereda fracture of a size sufficient to accommodate all the waste geothermal liquids. For these reasons,the conversion of one of the existing TGH's to a temporary waste geothermal liquid disposal well 1s also not considered a viable option. ' - Returning the produced fluids to the reservoir via the small diameter"resource confirmation well would be a relatively low-cost®"technically feasible alternative,except for the necessity of constructing a storage basin or other facility large enough to hold all the liquid produced from the well flow test prior to filtering and injection.A basin approximately 100-feet square and 4-feet deep would be the minimum required.Since no ° powered earth-moving machinery will likely be available at the site,a basin of this size would be very difficult to construct (although one alternative may be to dam a small gully near the site to form a storage basin).In'addition,the environmental impacts resulting from the construction and ©-es operation of such a basin could be significant.'However,this option remains )potentially viable.A Surface disposal of the waste geothermal liquids could be accomplished through discharge into a storage basin for evaporation,discharge directly onto the land surface,or discharge directly into tributaries of the Makushin Valley river.. . Discharge of the waste geothermal fluids into a storage basin for evapo - ration;in addition to having the problems associated with constructing andoperatingastorage'basin as described above,is probably impractical sincetheprecipitationrateaatthesitealmostcertainlyexceedstheevaporation pate.Thus,use of the basin would increase,rather than decrease,the waste liquids which must be disposed.° 147 a The 1982 environmental baseline data collection program (Appendix A) established late spring and early fall values for both Makushin Valley river water quality and freshwater aquatic biology resources.In general,water quality was pristine.Discharge was low in the spring and relatively high in the fall.Correspondingly,mineralization decreased from spring to fall,and turbidity and suspended solids increased over the same period.Fish 'sampling and observations established the existence of both Dolly Varden char (Salvelinus malma)and pink salmon (Oncorhynchus gorbuscha)in,the MakushinValleyriver.Because of their known sensitivity and commer 141 value,thepinksalmonaretheaquaticspeciesofgreatestconcern.No pink Salmon wereobservedupstreamofapointaboutthreemilesdownstreamoftheproposed discharge point. Republic will endeavor to have the fall pink salmon.spawning run- monitored,in cooperation with the Alaska Department of Fish and Game,from its beginning to approximately establish the size of the run and the upstream Timit prior to,during,and following geothermal waste liquid discharge.-Makushin=valley river water quality and flow rates will also be measured;>prior to,during,and following discharge at the Previously sotabtished iataroe"quality monitoring stations in Makushin Valley (Station MV and Station 8,vasshowninAppendixA)and a new station immediately downstream from the dis- charge point.Conductivity or chloride measurements will likely be used as the prime index of water quality in the field;however,we do anticipate .collecting a relatively complete chemical sample from Station wv both prior ;to and during the test.ae Bee st Environmental impact mitigation measures will consist of both measuresdesignedandimplementedasastandardpartoftheoperationalactivities,-and those measures designed to be implemented on a contingency basis 'shouldcertain.conditions arise., In addition to those impact mitigation measures implemented during the | 1982 field season,Republic will undertake special programs to prevent the B.Environmental Measures G: Environmental measures planned for the 1983 Makushin Geothermal Project field season are divided into environmental impact monitoring,environmental impact mitigation,and emergency contingency measures. Environmental impact monitoring measures planned for the resource confir-- mation well drilling and testing,and the resource delineation well drilling will consist of both Field sampling programs and operation inspection pro- grams. The 1983 operations will be inspected at random by environmentally trained personnet.The operations will also be nearly continuously monitored by supervisory drilling,engineering,and geological personnel.As was thecaseforthesimilaroperationsconductedduring1982,these inspections and monitor ing activities will help to detect and correct minor problems beforetheybecomemajorones. |Monitoring of the 1982 TGH 'dri1iing operations:confirmed that the 'Vkelt-|hood for significant environmental impacts from wireline coring drilling:_operations is remote.In addition,the analysis presented in Section A above indicates that inspected impacts resulting from the discharge of geothermal fluids in the Makushin Valley river are expected to be negligible.However, since this analysis is based upon a number of assumptions,including reser- voir and well production characteristics,dates of discharge,fish spawning status,and river flow rates,there is stil]a potential for impacts to Makushin Valley river water quality and freshwater aquatic biology resources. _The goal for the 1983 field environmental impact monitoring programis toallowearlydetectionofenvironmentalimpactssothatsignificantimpactscanbeavoided,and to establish the level of impact that may be expected should more significant discharges of geothermal fluid be required during future operations. 149 oethe Phase IA Report,plans for the deep well operations have been refined and additional permits have been determined to be necessary.The additionalpermitsaremostlyrelated,to the disposal of geothermal fluid from testingoperations(as discussed in Section VIII.A.)”- Contact with regulatory agencies was maintained throughout the operations in order to keep them informed of the status of both current operations and future plans.Extensive pre-application discussions were held with the ... Alaska Department of Fish and Game (ADFG)the Alaska Department,of Environ-"mental Conservation (ADEC)and the United States Environnehta}Protect tonAgency(USEPA)to determine the appropriate activities and oérmit(s)for the testing operations.The ADEC will require a Short-Term Water Quality Vari- ance for the temporary discharge of geothermal fluid into the stream which feeds into Makushin river.The ADFG will coordinate with the ADEC and will use the.Variance request and approval stipulations as a vehicle for theconcernsoftheiragencyregardinganadromousfishandstreamquality.The USEPA ...(Note to reader of Draft Report:Although an application to theUSEPAwas"submitted,"the USEPA wild most likely not require a permit.How-ever,they hhave.not yet officially made 'this:determination.)ERS fof Poe The following permit applications have been submitted,and copies are- included in Appendix M:(Note to reader of Draft Report:Not all applica- tions have been submitted as of this date.) M-1)Application for a Special Use Permit,submitted to the U.Ss FishandWildlifeServiceonFebruary24,1983; M-2)AShort-Term Water quality Variance Request,submitted to the Alaska Department of Environmental Conservation on February 24,- 1983;0-7 ve nO M-3)Letter to Alaska Department of Natural Resources regarding - proposed drilling operations,in the form of a carbon copy of the Special Use Permit Application,submitted on February 24,1983; 152 reoccurrence of fox feeding which took placein 1982.Republic will also design the flow test in such a way so as to minimize sediment impact to the river..oy Because the expectation that impacts resulting from the discharge of geothermal fluid into the Makushin Valley river will be'negligible is based upon a great number of assumptions,certain environmental impact mitigation measures need to be available on a contingency basis should these assumptions prove false.Should the environmental impact monitoring program establish _that actual impacts to the pink salmon from the test discHargé could begreaterthanthecurrentlyprojectedimpacts(due to lower raver flow,higher 'upstream migration,higher well discharge rate,or greater geothermal reser- voir salinity),a reduction in the actual impacts could be obtained by either lowering the rate of waste geothermal discharge into the river (by either decreasing the well flow rate or creating temporary surface storage to allow actual discharge to the river at a lower rate),or altering the date of waste geothermal fluid discharge to the river so that it coincides with a higher_tiver flow rate.Implementation of these contingency environmental 'impact"mitigation mmeasures will depend upon an analysis of conditions as actually |measured in the field.oe Emergency contingency measures have been developed for the 1983 field operations to deal with injury accidents,fire,security,well control,and emergency notifications.These measures have been compiled in an emergency contingency plan which is included in the Application for a Special Use -Permit submitted to the U.S.Fish and Wildlife Service as Section V, Emergency Action Procedures and Notification List (Appendix M-1,p.12-16).-A copy of the emergency contingency Plan will be at the site of field opera-tions at avy times._.;.Pe - C.Permit Applications Permitting requirements for the deep well drilling and testing operations were discussed in the Phase IA Final Report,Task 3.Since the submittal of EL Permit Approvals _ would cross some lands for which Republic had not yet recieved permission to cross,Republic requested permission from the Ounalashka Corporation and the Aleut Corporation to conduct operations'on lands additional to those for | which permission was earlier granted.Copies of these letters and the AleutCorporationresponseareincludedasAppendixN,as follows: N-1)Letter to the Aleut Corporation,dated August 26,1982; N-2)Letter to the Qunalashka Corporation,dated ragust 35.1982;)é "/ N-3)Letter from the Aleut Corporation,dated Septembet 3,1982; N-4)Letter from the Ounalashka Corporation,dated December 7,1982. Qo.Environmental Documents _Republic and Dames .and Moore held discussions with the U.S.Fish and.Wildlife:Service (USFWS)regarding the need for a Teview under the National ;Environmental Policy”Act (NEPA).'Based upon the {aformation contained in the"1982 Environmental Baseline Data Collection Program Final Report™and the.apparent minor impact from the 1982 operations,the USFWS did not require an Environmental Assessment prior to approval of the proposed 1983 operations. No other environmental documentation was determined to be necessary by stateandlocalregulatoryagencies. (Note to Reader of Draft Report:Not all permit approvals have beenobtainedasofthisdate.However,approval of all permits is anticipated by|the time the Final Report is completed.) 154 M-4)Letter Application for a Habitat Protection Permit,submitted to the Alaska Department of Fish and Game on March 1,1983; M-5)Letter to the United States Environmental Protection Agency requesting determination of the need for a permit,submitted on March 9,1983;- M-6)Letter from United States Environmental Protection Agency a requesting submittal of an Application for a National Pollutant Discharge and Elimination System Permit,dated March 28,1983; M-7)Application for a National Pollutant Discharge and Elimination System Permit,submitted to the United States Environmental Protection Agency on April 4,1983; M-8)Renewal letter for Temporary Water Use Permit 82-12,submitted to the Alaska Department of Natural Resources on April 14,1983; in ce 2oe4ga tow . M-9)Renewal letter for Solid Waste Disposal Permit No.8221-8A002;- submitted to.the Alaska Department of Environmental Conservation on April 14,1983;,; oe M-10)Letter requesting provision drilling authorization,submitted to the Alaska Department of Natural Resource on April 15,1983; M-11)Revised Application for a Food Service Permit,submitted to the Alaska Department of Environmental Conservation on ; M-12)Revised Application for a Drinking Water Permit,submitted to the Alaska Department of Environmental Conservation on a . Midway through the 1982 field season,the scope of the planned 1983 field operations was expanded to include the construction of a temporary road to provide access to the deep well site.Because all of the alternative roads awould cross some lands for which Republic had not yet recieved permission to cross,Republic requested permission from the Ounalashka Corporation and the Aleut Corporation to conduct operationson lands additional to those for which permission was earlier granted.Copies of these letters and the Aleut Corporation response are included as Appendix N,as follows: N-1)Letter to the Aleut Corporation,dated August 26,1982; N-2)Letter to the Ounalashka Corporation,dated August 26,1982; N-3)Letter from the Aleut Corporation,dated September 3,1982; N-4)Letter from the Qunalashka Corporation,dated December 7,1982. D.Environmental Documents Republic and Dames .and Moore held discussions with the U.S.Fish and Wildlife Service (USFWS)regarding the need for a review under the National Environmental Policy Act (NEPA).Based upon the information contained in the "1982 Environmental Baseline Data Collection Program Final Report"and the apparent minor impact from the 1982 operations,the USFWS did not require an Environmental Assessment prior to approval of the proposed 1983 operations. No other environmental documentation was determined to be necessary by state and local regulatory agencies. -E.Permit Approvals (Note to Reader of Draft Report:Not all permit approvals have been obtained as of this date.However,approval of all permits is anticipated by the time the Final Report is completed.) 4 154 All permits for the deep well drilling and testing operations have been C - obtained.The approvals are presented in Appendix 0,as follows:© 0-1)Letter from the Alaska Department of Fish and Game stating that as a Habitat Protection Permit is not necessary,dated March 8,1983; 0-2)Special Use Permit No.AI-83-27,approved by U.S.Fish and Wild- life Service; f 0-3)Short-Term Water Quality Variance No.8321-CA00],;approved by theAlaskaDepartmentofEnvironmentalConservationonApril14,1983; 0-4)Temporary Water Use Permit No.»approved by the Alaska Department of Natural Resources on ; 0-5)Solid Waste Disposal Permit No.»approved by the Alaska Department of Environmental Conservation on ; 0-6)Eating and Drinking Establishment Permit »approved by the Alaska Department of Environmental Conservation on : 0-7)Drinking Water Permit,approved by the Alaska Department of Environmental Conservation on ; 0-8)Geothermal Drilling Authorization,issued by the Alaska Department of Natural Resources on 155 ceREFERENCES Bamford,R.W.,Christensen,0.D.,and Capuano,R.M.,1980,Multielementgeochemistryofsolid-materials in geothermal systems and its applications Part 1:The hot-water system at Roosevelt Hot Springs KGRA,Utah:Earth Sci. Lab.,Univ.of Utah Research Inst.,ESL-30,168 p.' Black,R.F.,1975,Late Quaternary geomorphic processes;Effects on the ancient Aleuts of Umnak Island in the Aleutians:Artic,v.28,no.3,p.159-169. Capuano,R.M.,and Bamford,R.W.,1978,Initial investigations of soil mercurygeochemistryasanaidtodrillsiteselectioningeothermalsystems:°University of Utah Research Institute,Earth Science Laboratory Report1D0/78-1701-b..3.3,32 p.ie aD'Amore,F.,and Panichi,C.,1980,Evaluation of deep tempefatures of hydro-thermal systems by a new gas geothermometer:Geochimica et Cosmochemica ° Acta,v.44,p.549-556. Drewes,H.,Fraser G.D.,Snyder,G.L.and Barnett,H.F.,Jr.;1961,,Geology of Unalaska Island and adjacent insular shelf,Aleutian Islands,Alaska:U.S.Geological Survey Bulletin 1028-S,p.583-669. Ellis,A.J.and Mahon,W.A.J.,1967,Natural hydrothermal systems and exper i-ments hot water /rock interactions:Geochimica et Cosmochemica Acta,Ve 31,:Bees -ite te aatgheviedaeénh"ets,A.J:and|Mahon,WeA.Js,1977,'chemistry.and 'geothernal systems:NewceYork,Academic Press,392 p. Fang,S.C.,1978,'Sorption and transformation of mercury vapor by dry 'soll:| Environ.Science Tech.,v.12,p.285-288. Fournier,R.0.,White,D.E.,and Truesdell,A.H.,1974,Geochemical indicators of subsurface temperature -part 1,basic assumptions:Journal of Research,U.S.Geological]Survey,v.2,no.3,p.259-262.oo Fournier,R.0.,and.Truesdell,A.H.,1974,Geochemical indicators of subsurfacetemperature-part 2,estimation of temperature and fraction of hot water mixed with cold water:Jour.Research U.S.G.Se °V.2,no.3,p.263-270.Giggenbach,W.Fe,1980,Geothermal gas equilibria:Geochimica et CosmochemicaActa,v.44,p.2021-2032.;os Landress,R.A.,and Klusman,R.W.,1977,Nature of the occurrence of mercury insoilsofgeothermalareas:Geo.School of Mines,Dept.of Chem.and Geochem., Final Report,U.S.Geol.Survey Grant no.14-08-001-G-335,p.116. Maddren,A.G.,1919,Sulphur on Unalaska and Akun Islands and near Stepovak Bay, Alaska:U.S.Geological Survey Bulletin 692E,p.283-298. an. Mahon,W.A.J.,Klyen,L.E.,and Rhode,M.,1980,Neutral sodium/bicarbonate/ sulphate hot waters in geothermal systems:Jour.of Japan Geothermal EnergyAssn.,Vv.17,no.1,p.11-24. Matlick,J.$.,and Buseck,P.R.,1975,Exploration for geothermal areas usingmercury:A new geochemical technique:2nd U.N.Symposium om DevelopmentandUseofGeothermalResources,p.785-792. Matlick,J.$.,and Shiraki,M.,1981,Evaluation of the mercury soil:mapping geothermal exploration techniques:Geothermal Resources Council, Transactions,v.5,p.95-98.° McNerney,J.J.,and Buseck,P.R.,1975,Geochemical exploratfon using mercuryvapor,Economic Geology,v.68,p.1313-1320.teMcNerney,J.J.,Buseck,P.R.,and Hanson,R.C.,1972,ie bey detection bymeansofthingoldfilms:Science,v.178,p.e1l-612. Motyka,R.J.,Moorman,M.A.,and Liss,S.A.,1981,Assessment of thermalspringssitesAleutianarc,Atka Island to Becherof Lake -preliminary results and evaluation:Alaska DGGS Open-File Report 144,p.68-85.° Motyka,R.J.,Moorman,M.A.,and Poreda,R.,1983,Progress report .thermalfluidinvestigationsoftheMakushinGeothermalArea:Alaska bGGS,in.press,35 p., Phelps,0.W.,and Buseck,P.R.,1978,Natural concentrations 'of'Hg in the.Yellowstone and Coso geothermal fields:Geothermal Resources Council,:.°°"Transactions,v.2,p.521-522.Te ee Lh db:a Reeder,J.W.,1981,Preliminary assessment of the geothernal resources of 'the"northern part of Unalaska Island:Alaska Dept.Natural Resources,In Press. SEAN (Scientific Event Alert Network Bulletin)1980,National Technical Information Service,U.S.Dept.Commerce,pub.no.PR 81-9157. Truesdell,A.H.,and Hulston,J.R.,1980,Isotopic evidence of environments-Of geothermal systems:in Handbook of -environmental isotope.geochemistry,eds.Fritz and Fontes,p.179-219.., White;D.E.,1970,Geochemistry applied”to the discovery,evaluation,and-exploration of geothermal energy resources:Geothermics,Special Issue 2,p.58-80./- White,D.E.,Muffler,L.J.P.,and Truesdell,A.H.,1971,Vapor-dominatedhydrothermalsystemscomparedwithhot-water systems:Economics Geology,v.66,p.75-97.- C. Petrology of the Makushin Volcanic Field, Unalaska Island,Alaska by Sam Swanson Geophysical Institute and Geology/Geophysics Program University of Alaska May 17,1983 -_INTRODUCTION The Makushin volcanic field is a Holocene,tholeiitic province 7 . . located on the northern side of Unalaska Island in the Aleutian Arc. Glacial erosion has disected portions of the Makushin lavas,but isolated 2remnantssuggestaaerialextentofover400km”for the flows of basalt and andesite.A large composite volcano (Makushin)dominatesthe northern " part of Unalaska Island.Smaller cinder cones,some with associatediox} Unalaska Island lies on the edge of the continental shelf between lava flows,surround Makushin. North America and the Pacific Ocean -Bering Sea.Makushin Volcano thus marks the transition from oceanic -oceanic subduction of the western Aleutians to oceanic -continental subduction in the-eastern portion of the Arc.Both Marsh (1979)and Kay (et al,1982)place Makushin Volcano at the end of a volcanic arc segment,although the configuration ofsegmentsinthesemodelsofAleutianarcsegmentationarequitedifferent. The Makushin volcanic field is developed upon clastic sedimentary and volcanic rocks of the Unalaska Formation of Miocene Age (Drewes et al,°1961;Perfit et al,1980).Several plutons intrude the Unalaska Formation and are also unconformably overlain by the Makushin volcanic field.Radiometric ages determined on two of these plutons yield ages of 11 3m.y.(Marlow et al,1973)and 13 m.y.(Lankford and Hill, 1979).Individual plutons are zoned from mafic (gabbro)margins to felsic (granite)interiors and show calc-alkaline patterns of chemical variation (Perfit et al,1980). aUSSTORERERYGerece,SteeANALYTICAL TECHNIQUES Major Element Chemistry Major element chemistry was determined on 28 samptes of volcanic- rock from the Makushin volcanic field during this study (Appendix I).. The analyses were done at the Alaska Division of Geologic and Geophysical Surveys laboratory in Fairbanks.Samples were trimmed in the field to remove weathered material and ranged in size from 1 to 2 kilograms.The relatively large sample size was taken to ensure a homogeneous sample of the porphyritic rocks.Samples were ground in a crusher faced with tungsten carbide.A split of the crushed sample was powdered in a RockJab pulverizer.Fusion of a portion of the powdered sample with LiB0.produced a giass bead that was used in the analyses.Concentrations of 10 major elements were determined in the glass beads with a Rigaku X-ray fluorescence unit.Calibration curves for the analyses were constructed from 39 rock standards.Wet chemical techniques were used on a portion of the powdered 'samples to determine FeO,subtraction of this value from the totai iron resulted in a value of Feo. Trace Element Chemistry - Trace element concentrations were determined,in duplicate,on splits of 18 of the saiiples crushed for major element analyses (Appendix I).The analyses were performed by Chris Nye in the Earth Science Department at the Santa Cruz campus of the University of California.The powdered samples were.pressed,without binder,into boric acid-backed pellets. A Phillips AXS spectrometer automated by a Data General Nova 3/12 computer coilected dead time-corrected counts.A tungsten tube powdered by a Phillips 5000 generator provided the primary X-rays.Tube voltage and amperage were regulated to maximize the signal quality in each of the two analytical groups (Rb,Sr,Y,Zr,Nb,Ni,and Ce,Nd,Ba,Vv,Cr,La). Generator stavility was monitored by analyzing a single pellet ona regular basis throughout an analytica?run.Analytical data were corrected,via a Fortran 77 data reduction program,for peak overlap,matrix effects and linear and nonlinear backgrounds.Peak overlaps and backgrounds were determined on pure element standards.Corrected count rate data was regressed against concentration in at least 15 geological reference standards for each element.Concentrations are accurate to at least 5%relative "or 1 ppm,whichever is greater.In addition,V,Cr,Ni,'Ba nd Ce are accurate to 3%relative,but are no better than +2 -3 ppm.Detection limits for all elements are a few pom except for Ni and Ba,which have detection limits of 5 -10 ppm due to tube interferences. Electron Microprobe Analysis Mineral compositions of both phenocryst and groundmass phases were measured 'in 16 samples from the Makushin volcanic field.The analyses were done on a Cameca-electron microprobe at Washington State University. The accelerating voltage was 15 kv and the beam diameter was 1-2 microns. Nine elements (Si,Ti,Al,Fe,Mn,Mg,Ca,Na,K)were analyzed in each sample;oxygen was determined by difference.Standards were pure elements and oxides that gave satisfactory results on well-analyzed geological material.The excellent stability of the electron beam permitted 12 hours of analyses between redetermination of the standards.Analytical results were processed with an on-line computer and the results were printed out in weight percent. Over 350 analyses were made of plagioclase,augite,pigeonite, hypersthene,olivine and titanomagnetite.In phenocrysts,compositions were measured in the core and rim of a particular crystal.Due to the small grain size,groundmass phases were only measured in center of the grain.aa We eee oT SETLcaeEmtecteaee ee Modal Analyses Point counts were inade of over 50 thin sections using a Swift automatic point counter.Point spacing was 1.0 mm and 400 -500 points were counted per slide.Mineral percentages quoted in the text or in the petrographic descriptions (Appendix IT)are based on these modal analyses. .PETROLOGY AND MINERALOGY Chemical analyses of rocks from the Makushin volcanic field (Appendix I)show that basalt (Si0,53 weight percent)and andesite (Sid,= 53 to 63 weight percent)are the most common rock types,but some smal] amount of dacite (Si0,63 weight percent)is also found (Fig.1). Volumetrically,lava flows are the most important component in the Makushin volcanic field,but minor amounts of volcanic breccia and ow pyroclastic deposits are also found.Makushin Volcano is the source for most of the lavas in the Makushin volcanic field,but sate}lite vents atPakushinCone,Pt.Kadin vents,Table Top Mountain,Wide Bay Cone and Sugarloaf Cone (Fig.2)are locally important sources. Plagioclase,olivine,hypersthene,augite and titanomagnetite are the phenocryst phases in the Makushin volcanics.Plagioclase is the dominant phenocryst,but the coexisting mafic phenocrysts vary (Appendix II).In the basic.lavas (si0,52 weight percent),augite and olivine are the only maficphenocrysts.Hypersthene joines the phenocryst assemblage with increasing silica content and the olivine content decrease.Olivine is not found in rocks with a higher (Si0,60 weight percent)silica content and the phenocryst assemblage consists of plagioclase,hypersthene and augite. Pigeonite (small 2V,optically positive,moderate birefringence)is foundin the intermediate rocks (Si0,=53 to 60 weight percent)as rims on hypersthene and olivine phenocrysts and occasionally as descrete phenocrysts.Hydrous minerals are not'found in the Makushin volcanics.. Groundmass textures vary from holocrystalline aggregates of plagioclase, clinopyroxene and Fe-Ti oxides to hypocrystalline with smal]amounts of brown glass being found in the groundmass of some rocks. wes: 7OFANALYSISMAKUSHIN VOLCANIC FIELD WEIGHT Si0,-> 0 -Basalt Andesite |Dacite a -_| gb i | | 6 i -_| 4 r aD cee ! "a -_ry Lui ti jj iE Listy 45 50 55 60 65 Figure 1.Histogram of silica contents for lavas from the Makushin volcanic field._-_ 167°00'|:{66°30" ;i")38 ) , Table Top.Mtn. .36 |, 54°00'+Driftwood28)Bay 40 \ 42 | Pt,Kadin "Mokushin -49 veeiisi Volcano”;47 45 a Ped:})\C2 WiVolcanoQ or OK : Pakushin Y Cone ogRr'|_,Makushin Ave _leaoge!54°45 Bay ||04 45 0 i l l I 2kilometers N Contour interval 1000 ft.\| 167°00 {66°30 _Figure 2.Sample location map. oe Ameeemege EE at eewateeBieDTaeSL Tes Plagioclase Plagioclase is the most abundant crystalline phase in the samples. Single crystals of plagioclase exceed 5 mm in length,but a7 -2 mm Tength is more common,Plagioclase crystals form glomeroporphyritic masses,especially in samples from Pakushin Cone and the Table Top Mountain- Wide Bay Cone area. Normal zoning,from a Ca-rich core to a more sodic rim,is found in most of the plagioclase.Zones of inclusions (glass,pyroxene and " opaque minerals)are found in some of the plagioclase,either in the crystal core or concentrated in a zone between the core and rim.Microprobe ; analyses show phenocryst cores are 10 -30 percent richer in the An component than the rim.(Fig.3).Groundmass plagioclase compositions show the same compositional range as the phenocryst rims and are not distinguished on Figure 3. - Piagioclase from the older and recent Makushin volcanics and from the satellite vents show similar patterns of variation (Fig.3).Anorthite- rich plagioclase cores are found in samples from all three rock units and the pattern of normal compositional zoning is similar in all the phenocrysts. Clinopyroxene Augite and pigeonite are found as -both phenocryst and groundmass phases in the rocks of the Makushin volcanic field.Augite is usually the most abundant mafic mineral in the samples.Single phenocrysts range in size from 1 to 5 mm in maximum dimension and are not pleochroic. Glomeroporphyritic augite is found in some samples,especially those from the Table Top Mountain-Wide Bay Cone area.Augite is also found as a rim on some olivine and hypersthene grains. ;,;Lo Figure 3.Plagioclase compositions in pre-glacial (older,A)and post-glacial (recent,B)samples.from the Makushin volcanics and from satellite vents (C)in the Makushin volcanic field.Circles (©)represent phenocryst cores and crosses (%*)represent phenocryst rims andgroundmassplagioclasegrains.' or } be a) were Tetoeeee a aeThlleBOERSmetclaLee OtMicroprobe analyses of augite phenocrysts (summarized on Fig.4)show Tess than 5 mole %MgSi0,variation from core to rim.The typical pattern of zoning is from Mg-rich cores to Fe-rich rims,but this pattern is reversed in some grains.'Augite rims on olivine and hypersthene compositionally correspond to the cores of the augite phenocrysts.Some augite phenocrysts from basalts in the Table Top Mountain-Wide Bay Cone area and from the older Makushin volcanics are high in Al (up to 6.3 wt %A1,03) compared to the other augite (avg.1 -2 wt %A1,0,).Augites from the various units in the Makushin volcanic field are similar in composition (Fig.4),but the augites in the recent Makushin volcanics are slightly more Fe-rich._Augite cores from the satellite vents are slightly more primative (higher Mg and Ca)than cores from the older Makushin volcanics. .Pigeonite is found as rims on some pyroxene crystals.and as small grains within the groundmass of rocks of intermediate composition (Si0,=53 to 56 wt %).The limited number of pigeonites analyzed (Fig.4)© do not'Show any systematic difference between the volcanic units. Hypersthene Hypersthene is found as both a phenocryst and groundmass phase in' samples that contain at least 53 wt %Si0,.Phenocrysts are commonly less than 1 mm in maximum dimension and display a light green to light pink pleochriosm.Some hypersthene grains are rimmed by clinopyroxene. Microprobe analyses (Fig.4)show the hypersthene has a higher Fe/Mg ratio than coexisting augite.Hypersthene phenocrysts are zoned less than 3 mole %MgSi0,,the cores are typically more Mg-rich than the rims. Phenocrysts from the satellite vents are richer in Mg than other phenocrysts (Fig.4),but some groundmass hypersthenes in the older Makushin volcanics have similar compositions.Generally,the hypersthenes from the different. units have very similar compositions. LSES»OsOey.: Figure 4.Pyroxene (circles)ard olivine (triangles)compositions from the pre-glacial (A)and post-glacial (B)Makushin volcanics and from the satellite vents in the Makushin volcanic field (C).Filled symbols represent phenocryst cores,open symbols represent phenocryst rims and groundmass grains (pyroxene only). lee BR ee ieee Olivine Olivine is found as phenocrysts in rocks that contain Tess than 53 wt %Si0,.The phenocrysts range in size from 1 to 3 mm in the largest dimension and vary from anhedral,rounded grains to enhedral phenocrysts. Some olivine grains are rimmed by clinopyroxene. Microprobe analyses of olivine show compositional variation of 28 mole %MgoSi0,(Fig.4).Normally,individual zones phenocrysts vary in composition less than 16 mole %Mg5Si0,from core to rim.Olivine from the different units show similar ranges of compositional variations. Oxides Titanomagnetite and rare ilmenite have been identified as phenocryst and:groundmass phases (titanomagnetite only)in the Makushin volcanic rocks. Phenocrysts are restricted to rocks that contain 51 wt %,or more,Si0, and vary from enhedral to anhedral.Fine-grained,subhedral to enhedral oxides ake a ubiquitous part of the groundmass assemblage. ;Microprobe.analyses reveal -that titanomagnetiteis the dominant oxide phase.Composition of the spinel varies from 25 to 52 mole % FeTi0,.Both phenocrysts and groundmass spinels show similar ranges of compositional variation.A single ilmenite phenocryst (4 mole %R503)was identified in one sample. GEOCHEMISTRY Major Elements”-a aon Major element analyses for 58 (28 new)lavas from the Makushin volcanics are given in Appendix I.These analyses include samples from the satellite vents as well as samples erupted from Makushin Volcano (Makushin volcanics).An attempt was made to distinguish between older and younger (recent)units within the Makushin volcanics based upon thé amount of glacial erosion (Fig.5).As used in this report,older.Makushin volcanicspre-date a major period of glaciation on Unalaska Island dad thus form "isolated ridge-capping outcrops or are exposed in the steep walls of glacially-carved valleys.The exact timing of this glacial event (and hence the upper age limit for the older Makushin volcanics is not known on Unalaska.Elsewhere in the Aleutian Arc,Black (1975)dates recession of this latest period of glaciation at 10,000 to 11,000 y.b.p.on Atka Island and Funk (1973)gives an age of 6,700 y.b.p.for the same recession at Cold Bay on the Alaska Peninsula.The recent Makushin volcanics ) post-date the last major glacial advance and fill glacially-carved ,valleys.Relatively smooth,undisected slopes on the north and southwest flanks of Makushin Volcano are related to a covering of these younger Makushin volcanics.Another sequence of younger Makushin lava flows fills a glacially-carved valley on the eastern flank of Makushin volcano in the vicinity of Sugarloaf Cone (these are the flows of the DI drill site).Some recent.samples from the Makushin volcanics are loose blocks and bombs collected from the rim of Makushin Volcano and from surface pyroclastic deposits around the flank of the volcano.These blocks and bombs probably represent the most recent eruption of Makushin Volcano. 54°00' 54°45' 167°00'{66°30 |cd Driftwood .. Boy Pt.Kadin , 7..frewcatetisFgOta7 LEGEND Surflclal Deposits fs]Elder Pt.Basalts Makushin Volcanics Postglaclal/Preglacial Volcano Bay .UnalaskaMakushin[_}Formation and |Gay Dioritic Plutons O 5 Lot |oa |LJ kilometers 167°00! Figure 5.Geologic map of the Makushin volcanic field,Modified from Drewes (et al.,1961). etSeeeeVariation diagrams for samples from the Makushin volcanic field are presented in Figures 6 -11.The patterns of chemical variation is typical of many Aleutian volcanoes.The rocks are rather alumina-rich (15-22 weight percent):and the potash variation corresponds to the high potassium trend defined by March (1982)for the Aleutian Arc.Other , components,such as MgO or Ti0,(constant at about 1-weight percent, Appendix I)show characteristically low values typical of Aleutian volcanics (Marsh,1982).Some samples of basalt showpetrographic evidence for the accumulation of augite,olivine and/or plagioclase Ain the magma chamber prior to eruption.Such crystal accumulations are reflected in the variation diagrams.However,most samples do not show any petrographic evidence.for crystal accumulation and their compositions form smooth curvilinear patterns of variation.Older and recent Makushin Tayvas define the same variation pattern,but the recent Makushin lavas are the most fractionated rocks analyzed from the Makushin volcanic field (Fig. 6,8,and 10).Samples from the satellite vents show patterns of variation thet are identical to the patterns defined by the Makushin volcanics ) (Figs.7,9,and 11). Fractionation in the Makushin magmatic system results in a moderate amountof iron enrichment.'Figures 8 and 9 show the relative increase in iron with respect to magnesium with increasing silica content.The compositional fields for tholeiitic and calc-alkaline lavas as defined by Miyashiro (1974)for subcuction-related magmas in the Japanese Islands are also shown of Figures 8 and 9.Kay (et al,1982)and Kienle and Swanson (1983)used the Fe0*/MgO vs.Si0,variation diagram to distinguish calc-alkaline and tholeiitic fraction trends in the Aleutian arc.Samples from the Makushin'-volcanics and the satellite vents plot %Alo Oz %Feo”8 %MgO MAKUSHIN VOLCANIC FIELD 2 eT aa "ee xe * e %¥tTTTPteer °Bees0°cary®e °*%*rytTTdrrerrprrbrse4Makushin Volcanics é o's o*Recent e Older oeeeeeeeeersryof.a.2kLSewstceasbtscoseito#6 geLutPrepttprptpt_pt_prtperptreypppsy 50 55 60 65 %S iO5>Figure 6.Harker variation diagram for the Makushin volcanics. MAKUSHIN VOLCANIC FIELDSATELLITEVENTS 20 T fmm aA="A % 18 a vA 2 se.ba -"fo AloOz wef ha ANH oy ' a NS "SAL '4 14 Ba re "s.i raLe/i %FeO -A te '6 - * . 4 AN AS 4 A / =t8aa {a aA%MgO SF &AL\4 \,ii er =oe a TTS2iare'all H >.:Tse -O : 12 CBN 10F \" a>-%CaO0 fF NAAT TS,. 8Fr Se "A x x __L.A bh6aNd .4 C -oPat- '*4Na50 4}ee Se a ee,2}i aa As ara %Ko0 of caoonVeefe)Fe Oe errO505560.65 Figure 7.Harker diagram for the satellite vents in the Makushin volcanic field.Dashed line -. from Figure 6 represents compositions of the Makushin volcanics. MAKUSHIN VOLCANIC FIELD 64r 62r Makushin Volcanics %Si05ox Recent e e Older 46 \{|! 1.0 20 3.0 4.0 FeO*/MgO- Figure 8.FeO/Mg0 vs SiO,diagram for the Makushin volcanics.Calc-alkaline/fholeiitic (CA/TH)is from Miyashiro (1974). .l "1 1.0 2.0 3.0 40 Feo”MgO -°-= Figure 9.Fe0/Mg0 vs Si02 for satellite vents in the Makushin | volcanic field.Calc-alkaline/tholeiitic (CA/TH)is from Miyashiro (1974). MAKUSHIN VOLCANIC FIELD Feo* Makushin Volcanics °*Recent ©Older Na,O+WA K50 Figure 10.AFM diagram for the Makushin volcanics.|Sihdu MAKUSHIN VOLCANIC FIELD Feo* Figure 11.AFM diagram for the satellite vents in the Makushin volcanic ... field.Dashed line is the trend defined by samples from the Makushin volcanics and is taken from Figure 10.waitHbnb in the tholeiitic field (Figs.8 and 9).Kay (et al,1982)considered the Makushin volcanics to be "transitional"between tholeiitic and calc- alkaline,but the current study (besed on approximately three.times more. analyses than was previously available)clearly shows the tholetitic character of lavas from the Makushin volcanic field.Slight trends of iron enrichment characterize the Makushin volcanics and the lavas from the satellite vents on AFM (alkali-iron-magnesium)variation diagrams (Fig.10 and 11)compositional trends for the satellite vents are similar to those of the Makushin volcanics (Figs.8 and 9). Trace Elements Trace element.analyses were done on 19 samples as part of this study (Appendix 2).Several partial trace element analyses were also 'reported by Reeder (et al,1982)and McCulloch and Perfit (1981).Trace elements commonly show a greater level of variability (often greater than an'order.of .magnitude for a given element):than major elements and are sensitive to magma source regions and subsequent frationation processes. The Tow concentrations of trace elements make analyses difficult and this creates particular problems in trying to compare results from different laboratories that utilize different analytical techniques.To date,it has not been possible to compare techniques used by McCulloch and Perfit (1981)or those of Reeder (et al,1982)with those in this study.However,the trace element results of this study define trends that are generally followed by the data of McCulloch and Perfit (1981) and Reeder (et al,1982)suggesting that the different studies yield similar results.tahni Trace elements may be divided inte different.groups based on their geochemical behavior (controlled largely by ionic size and charge,Gill, 1981).Several such groups were analyzed in the Makushin volcanics.-'ghai.Cations with a large ionic radius and a low charge form the K-group.. These elements are fractionated into the liquid during fractional crystalli- zation in basaltic and andesitic systems and their concentrations thus correlate with other measures of fractionation,such as increasing Si. In addition to K;Rb,Ba and Sr from the K-group were anélyzed (AppendixI).Rare earth elements (REE)together with Y do not!preferentiallyconcentrateinpyroxenes,olivine or plagioclase and thus these elements may provide information cn Tava sources prior to extrusion.The light rare earth elements (LREE)La,Le and Nd were analyzed in this study (Appendix I).High field strengths (high charge,small ionic radius) charaterize the elements of the Ti-group.These elements are not fractionated into any common basaltic or andesitic minerals with the exception of Ti in magnetite and ilmenite.Members of the Tf-group thus correlate positively with each other and with measures of fractionation.(such as increasing Si).Zr,in addition to Ti was measured from the Ti-group druing the present study (Appendix I).The compatible group elements (Ni,Cr and V of the present study)are more concentrated in the Fe-Mg silicate minerals than in the coexisting liquid phase and these elements thus show a negative correlation with Si. Variation diagrams for some of the trace elements are shown in Figures 1A-15.All of the trace element data known to the author is consistent with a comagmatic origin for the Makushin lavas (bath early and late)and the lavas from the satellite vents.The smooth patterns of variation in both the trace and major elements suggests a similar pattern of fractionation for Makushin lavas and lavas erupted from the satellite vents. Ti(ppm)(x10)Makushin Volcanic Field c<] =A ]40 2 s -g °8 Z [ }gQ . 20 nm oA areg O i {!i _t {q !i i J L i]L}4 1 i t []q q t 1 Makushin Velicanics8O0O0f-= .*,o recent LL aA o older 4 Satellite Vents 600;° ;Z °°bd A ° 5400;2°8 4 200 t _}J !i]J t j t aa ! 1 T im q q 4 dq q t I qT 8F-_ A a >° _ *cs )cs )6E Q 20 2 = °OA A °%Oo a 0 _ 4 1 7 4 1 iY 1 !1 tf 20 60 100 140 180 220 ZT (ppm) Figure 1h Plots of Y,Sr,and Ti vs Zr abundances in samples from the Makushin volcanic field. WIQNWUOE VOIUaAIN FIeIa E Q a. wT cs _ |*,O recent - o older |Satellite Vents { cron E a. Qa -_ oS - NB (ppm) Figure 12.Plots of Ba.and Nb vs La in samples from the Makushin volcanic field.old. Makushin Volcanic Field 1007 |l l l yl l l l !TT soL - ["L = <c \.omesolfoe)*s bd " £°Se %°° Oo 40Fr .© °*=| ow ; -J goh "*77 4 _Makushin Voleanics - Le °.°:sk,0 recent D9 ooL ae 7 °©older a oo °an .Satellite Vents a . A 10 l ! .48 50 52 "54 56 58 60 -.:«62 %SiOo [ Figure 13.La enrichments vs SiO)contents in samples from the'Makushin volcanic field.The value used for chondritic La is 0.33 ppm. %SiO.-NM kushin VolcanicF Id - 64 ee =.*4 62- °§Makushin Volcanics 7 _@ *,o recent. Z o older ;7 .Satellite Vents 60-- |A .4 oA a A an - |7.58 KS | Z on 2 Oo oO -A A z O = fe) t . "64 Oo e>7 S a oe - ., 52,,° - eo @ a A 4 t+ C)50--= o a 7 fA 48 j J j J j J ! 0 100 200 00 400 V (ppm) Figure 14.Variation on V with Si09 in samples from theMakushinvolcanicfield.i4ticdh. Makushin Volcanic Field 400 t T T 1 T T T T T T T LL A *i ;e A :300 ;°2 5 ss ee e o °@ - =tay . ..20 one2cook.|8 4 .Makushin Volcanics 0 6 -3*,o recent *4 100};e older °4 Satellite Vents bd a 7 O J t }}!|i }ij a]y 0 100 200 300.400 500 600 Ba (ppm) Figure 15.Variation of Ba with V in samples from the Makushin volcanic field.edeat Reeder (et al,1982)report differences in composition between the trace elements of Table Top lavas and other lavas in the Makushin volcanic field.In particular,these workers cite lower K,La and.Ba contents; higher Sr levels,and differences in K/La and Ba/La ratios.Viewed in the context of the present data,the Table Tcp lavas do not appear significantly different.The Ba/La ratios are within the scatter of the Makushin data (Fig.12).Further testing of this Lrhypothesisiswarranted,but based on the current data base all of the i.eTavasintheMakushinvolcanicfieldappeartobecomagfiatic.vieAYES walDISCUSSION Several lines of.evidence indicate that the rocks of the Makushin sale.volcanic field (both satellite vents and Makushin volcanics)are comagmatic. First,the basalt to dacite series plots as coherent and continuous trends on variation diagrams involving silica,zirconium or other measures of fractionation (Figs.6,7,and 11).Deviations from these continuous trends can be expiained by local crystal accumulations (such as the glomero- porphyritic plagioclase or augite).Second,mineral compositions from the different map units within the Makushin volcanic field are quite uniform (Figs.3 and 4).Third,the reactions relations indicated by reaction textures in the rocks or the restriction of certain phases (hyperstene,olivine or pigeonite)to limited ranges of bulk composition. Rocks from all units within the Makushin volcanic field show the same type of reaction relations.For example,the occurrence of pigeonite is restricted to rocks with more than 53 wt %Si0,in not only the satellite vents,but | also in the Makushin volcanics.The similarity in major and trace element variations and the pattern of mineralogic diversity suggests the rocks in _ the Makushin volcanic field are comagmatic. Fractionation Perfit and Gust (1981)suggested that compositional diversity in the Makushin volcanic field is related to a fractionation scheme involving plagioclase,augite and possibly olivine and magnetite.Figure 16 is a test of this fractionation scheme using a basalt (M-27)and a dacite (M-43c) together with average phenocryst compositions from the more basic bulk compositions.The results of this fractionation test confirm the results of Perfit and Gust (1981).Based on experimental studies in basaltic systems at 1 atmosphere (Presnall et al.,1978),plagioclase +augite +spinel 4D 30r io.20 30.40 50 bo. Wry Si 04, 4 2 t ++330HoSobo Jo wt lg Feo*¥ Figure 16.Plots of augite (aug),olivine (01)and plagioclase (pl) compositions in a basalt from the Table Top-Wide Bay , Cone area.Also shown are compositions of a basalt (M-27)and a dacite (M-43c)from the Makushin volcanic field.Fractionation of plt+oltaug can produce the variation in lava composition (M-27 to M-43c).faaal:dota0 KO Figure 17. .Ma0 AFM diagram illustrating the difference between the lavas of the Makushin volcanic field (circles,0)and rocks from_the Captains Bay pluton (crosses+,after Perfit,et al,_1980). bor ° °© Yor 4 éto?©i %+o +-goer te.+¢4207ot+t tt°+ r+ +A x 4 2 4 A.A.S oa bo 1dd 40 Ig 22»=A480=x (Pe) Figure 18.Differences in trace element behavior in the Makushin volcanic field (circles,o)and in the Captains Bay pluton (crosses4,after Perfit et al 1980). fractionation is an indication of low pressure differentiation in basaltic systems.Such low pressure fractionation is consistent with the pigeonite reaction relations fround in the Makushin volcanic field." é Plutonic vs.Volcanic Fractionation Perfit (et al.,1980)developed a fractionation model for the Captains Bay pluton on Unalaska Island.This model has been used to describe fractionation in Aleutian volcanic systems (Kay et al.,{982).Major element chemistry of samples from the Makushin volcanic Field apd from the CaptainsBayplutonaresimilar,but the volcanic rocks seem to show an iron-enrichment trend that is not found in the plutenic rocks (Fig.17).Temperature-oxygen fugacity relations in the plutonic and volcanic systems were apparently different.Other differences between the plutonic and volcanic systems are apparent in the trace element systematics (Fig.18).Differences between the volcanic and plutonic rocks are probably related to differences in température and-oxygen fugacity in these Shal low-level magmatic systems. _Such differences will control the sequence of crystallization in these ) systems and hence the pattern of fractionation.The plutons on Unataska are thus not exact analogues to the magmatic system under the Makushin volcanic fieid. CONCLUSIONS The Makushin volcanic field is underlain by a single magma body that is fractionating at shallow depths and feeds eruptions from the central vent (Makushin Volcano)and from the satellite vents.Assuming that the shape of the sub-Makushin magma system approximates the distribution of volcanic vents (somewhat eloncate northeast-southwest with Pakushin Cone and the Table Top Mountain-Wide Bay Cone areas at opposite ends),taheletihal: the margins of the magma chamber erupt lavas that are more basic than the central vent (Makushin Volcano).The alleged margins of the magma chamber also show more evidence for crystal fractionation in the form of crystal clots of plagioclase and augite.Thus,the sub-Makushin magma chamber seems to have mafic margins and a slightly more fractionated interior,similar to the compositional pattern observed in the plutons on Unalaska (Perfit et al.,1980).However,the details of.crystal fraction- ation in the volcanic and plutonic systems appear to be different.tofiswlas hufebil.ACKNOWLEDGEMENTS VstiChris Nye assisted the author in the field and also preformed the trace analyses.His good humor proved a real asset during many a cold,wet Aleutian day.Scott Cornelius,Washington State University,assisted the author inthemicroprobeanalyses.John Reeder,ADGGS,provided phe author with data on the composition of Makushin samples.Charlie Langmuir provided the author™ with trace element data that allowed for a more complete understanding of the Makushin system. ey Roman Motyka,ADGGS,was responsible for dragging the author out to Unalaska.Without his prodding,the author would have not been involved in the Makushin project.I appreciate the opportunity to Able been a part of the Makushin work. in .-_ REFERENCES CITED Black,R.F.,1975,Late Quaternary geomorphic processes:Effectson the ancient Aleuts of Umnak Island in the Aleutians,Arctic,v.28, p.159-169. Drewes,H.,Fraser,G.F.,Snyder,G.L.,and Bennett,Jr.,H.F.,1961, Geology Unalaska Island and adjacent insular shelf,Aleutian Islands, Alaska,U.S.Geol.Surv.Bull.,1028-S,p.583-676. Funk,J.M.,1973,The late Quaternary history of Cold Bay,Alaska and its implications to the configuration of the Bering land bridge,Geol. Soc.Am..Abs.with Programs,v.5,p.162. Gill,J.B.,1981,Orogenic andesites and plate tectonics,390 p., Springer-Verlag,New York. Kay,S.M.,Kay,R.W.,and Citron,G.P.,1982,Tectonic controls on tholeiitic and calc-alkaline magmatism in the Aleutian arc:J.Geophys. Res.)v.87,p.4051-4072. Kienle,J.,and Swanson,S.E.,1983,Volcanism in the eastern Aleutian arc:JTate Quaternary and Holocene centers,tectonic setting and -petrology,J.Vol.Geotherm.Res.,in press. Lankford,S.M.,and Hill,J.M.,1979,Stratigraphy and depositional environ- ment of the Dutch Harbor memberof the Unalaska Formation,Unalaska Island,Alaska,U.S.Geol.Surv.Bull.,1457-B,BI-Bl14.. Marlow,M.S.,Scholl,D.S.,Buffington,D.S.,and Alpha,T.R.,1973 Tectonic history of the central Aleutian Arc,Geol.Soc.Am.Bull., v.84,p.1555-1574. Marsh,B.D.,1979,Island-arc volcanism,Am.Scientist,v.67,p.161-172.taal :ahs:-weepeyi,oregettheofKe+SORRAUTEMEReet:.McCulloch,M.,and Perfit,M.,1981,'*3ndy'44na,87 constraints on the petrogenesis of the Aleutian island arc magmas, Earth Planet.Sci.Lett.,v.56,p.167-179.ernie Miyashiro,A.,1974,Volcanic rock series in island arcs and active continental margins:Am.J.Sci.,v.274,p.321-355. Perfit,M.R.,Brueckner,H.,Lawrence,J.R.,and Kay,R.W.,1980,Trace element and isotopic variations in a zoned pluton and associated rocks, Unalaska Island,Alaska:A model for fractionationin the Aleutian a)calc-alkaline suite:Contrib.Min.Pet.v.73,sp.69-87. Perfit,M.R.,and Gust,D.A.,1981,Petrochemistry and'experimental crystallization of basalts from the Aleutian Islands,Alaska (abstract), 1981 IAVCEI Symposium,Arc Volcanism,Tokyo and Hakone,Japan, p.288-289,Volcanol.Soc.Japan,Tokyo,1981. Presnall,D.C.,Dixon,S.A°,Dixon,J.R.,O'Donnell,T.H.,Brenner,N.L., Schrock,R.L.,and Dycus,D.W.,1978,Liquidus phase relations ---on-the.join diopside-forsterite-anorthite from Tat m to 20 k bar: _their bearing on the generation and crystallization of basaltic magma:Contrib.Min.Pet.,v.66,p.203-220. Reeder,J.W.,Nichols,C.,Motyka,R.,and Henning,M.,1982,Makushin Volcano geothermal resources,informal report,Alaska Division of Geological and Geophysical Surveys,submitted to the Alaska Power Authority. sr/eosr and trace element.imlilalt Appendix I Recent Makushin Volcanics Loose Block and Bombs from Crater Rim and Flanksof Makushin He MAAN OwowMmonw xt w ° Te) DwWWM 1WAWMNDOMmMNet Lo fos) $ J eo ee e|o©©# #© e@ e@ e « ' e t MOW, WONTMNO N co wmw elon) lO] OO et a oA wo ' Os N me)re oreeeeaeenemmeemmeaencca Se SR A SO o Vs ne 3) ad oOOt ReTAM OM OtMO a) eo x oO ond eo ee¢@#©@@@#@e e e e e KN MOexHtiodOOad tN© oo m we wo {Fo} eq | LS SS EEETCENESESANSCECEE GETTER CORESEDCEDSEEDpoeOEeaeCeeeeeeseeeeeeeeeeeeeeeeeeeoeeeeeeeeeeee LC) OMmMMOWNOAAmH © oo <r OOOn N MtWwOM tN om w © - J eo ©8@ee@@#@@ e6 e ° e 1 NtMOWtooOetrMOnN © oo s+ [oe] Wo C=wo- . Can!JeEDcDSSGYSEEGNSENSGERENSEDSDIGeGUNDSENNoemeeeeeeSoeeygemsGeeGENET)SUMEDGEESGEESSEGSGDGDSEGENTeSSDeSGESSeoeeeoeHH) WOOPTMEAMATAOM MM wn io) im OetTMNO KRFAINMWWA NN s+ mw oa ms 7 e¢ eee.°eeee .. e e ee . e ' metMm NIOON WOta© oo - MUMAMMOMAMWAOWOAAM© hsVey _ AMMAN AMN MO < N rom eo et mo oO MAPOW HOM aN on [oe] N mr) NNOOAON HMN AAA own + ° ° al *0©©©©©©8@@ oe . 0c wo ' MOMMA sTONnTNONO oo + et =Oo aee rn nnnnennnnnren een ee LO OMmn AOC OMnN Oct on ae) NttOoMetet tMOWN On a N foe]- ee¢ es e ee @ . es ¢ oo °@ . . e ' OmAm™NMON Ott © oOo - oa 'oO awoH et anfeeeASDNEDOSDSOA SENNSESNEGREfatONDSDSYKDGETSNDGELGLNDSEEDGERENSMEYGAMING GGEISSGemtNSDGEDGOEYSROUEDGELNAYGEENNDGECRDSAD © ONAAMDBDWANAM ot et m NnMm e ATM TEN MHMON Cae) + fo) aa °*.°eee°°ee e° e e e ' NOMMNMOnRTtTIANO oo -0°ia wn" omere] - oa be NNMMODDOODOWO+1 _ i=2) YVNROOGKGBDVUV>S LOOwerAwk& Oooov ena vNno oo Le)= OM BOK MNYO NZO Oomzaenn em NAL SEO owA AEN 4 - oo AO (an) mS i= Neem wv =a. =x o* S&Sw@Pea a waea lw adQ EW as oe wv c.0) bad ba .| C- -- wvsé 're e +from Drews (et al.,1961) *analysis by DGGS for J.Reeder;trace elements by C.Langmuir,Lamont-Doherty ITT"if 4Fl1 Recent Makushin Volcanics oySWFlankof _..MakushinD-1 Section 12* c i © m WONDMmM DAW etm WOM FW woo oO an *e6e.eeeeee e° e e WOWNNOMERMAHO oo = w WW” et . os MNOAMNRNOMHOAH MOH + ! ONNAAOAMNNMA4 oo ra) to : Vs) eee°°ee e e ee e . e MOAMMOMAMOO oo uw WwW A i ALAO<rLNOOmet£9CON (oe) HOMWwW AWW ODMN ed w we eeeeeeeeeee e e e Me NOMEN MAO N a Orn won oot a Ne peer tt N WOm +NO Ww tO x TOTMNAAWOMUATN N (ow) [a] eeee eee °e e e . WAKRNMNOMNE MAO N Ow + Ow ron) a mne”e Va) arm et w ah © wow NOM OntOnn NO s+ (an) .|e ee @«4oo e¢ @6e ' . e . winnww iigt MHO oo eq fon) lo od paar LesemeeeweeHee Mn creeeeseseSmsSS eSee SM eeSSSanneehcDSSSEEDONESGDNDnentsNDnDGeeeSSoes MNOMODMUNOATRt CO DM\ Too TPA AMORA ATN o.c wsN Oet [on eeeeeeeeeee ee e e °. ee e WARNMNOMN MAO oo oOo wm ANDPTOMOONWMNUWOAMONWO wea (an) ANNO MAMAMNM on) on ea rd et N a faa a te te etee ee ec ea aeSngheeeeeeaweeymYeeeeeceeeeHeHe NWOWMADAOMAMA Ot s+ oN . a WNMAMO AOR HOM oo im wo Lo oOo ran) .ee.e.eesee e . e e . MmONnRNMNON Ot HHO oo n ww MMMM UWOTFAHAWMNHWteOMYO et oO AMNAAMNM wo Lo an Lo ¢ et et roe) ae - siean7anneeeee NWO © fa) m+33Oo OP GQGOAGL BYU LNO> Lea at CONNDCO0O ANDOO Qo YS OER OCOHKMQANHAIOZ NZO OmtAemn mmm VYUVe MD DAA AEA [oe] *” owpm ia [o) SN Mt Caw Troztzrea ax »oOBK EFaed 8 wo o Pom « - fa om ro eee < wvsZ a ; omoma tfrom Drewes (et al.,1961) *xanalysis by DGGS for J.Reeder;trace elements by C.Langmuir,Lamont-Doherty Recent Makushin Volcanics Southeastern Flank,Makushin Volcano DerrrsU-194-R-4 JU-194-R-5 U-208-R-1I [U-208-R-2wtallU-34-S-167U-36-S-1||I ] I I qT T |J q | Side II 57.08 |57.00 ||54.94 |54.61 ||53.56 |53.85 Tidg II 0.90 {|0.90 |{1.00 |0.99 |}1.02 |1.02Al2031117.22 |17.74 ||17.43 |18.26 |}17.99 |18.69Fe7031|2.84 |2.75 ||3.12 |4.55 -|}2.85 |6.30 Fed ||4.95 |4.91 |1 5.19 |4.17 ||6.68 |2.95 MnO [|0.18 |0.17 ||0.20 |0.17)||0.28 4+0.18 MgO II 3.96 |4.00 ||3.62 |3.32 |1 4.31 |4.15 Cad [I 7.48.|7.55 ||8.14 |8.02 ||8.46 |8.49 Nao0 [I 3.31 |3.65 ||3.05 |3.57)|f 3.42 |3.41 K20 II 1.54 |1.42 ||}1.16 |1.00 |}0.95 |1.01 Po05 II 0.25 |0.15 ||0.23 |0.19 |}-0.20 |0.18 il ||||||| Ho0”||||||||| H90.II |||||{| II ||||"||| total 100.96 |100.88 !|99.32 !99.22 !|100.37 |101.25-| Fe0*/IMg01 |1.89 |1.85 ||2.21 [2.49 ||}2.81 |2.08 II ||||||| trace ||I =||||||elements}|||||||I (ppm)||||ee ||l K(x1,000)1]12.8 |-11.8 ||9.6 |8.3 ||7.9 |8.4 Rb |]1}||||| Ba Il 463 |460 ||379 |377 ||323 |337 Sr I|377 |371 ||390 |393 ||397 |410 La {I |||||1 7.5 Jf. Ce Il ||||||| Nd II |||||l | Yd ||||||| Zr {I ||||I | Nb JI |||-|||| Ti(x1,000)1]5.4 |5.4 ||6.0 |5.9 |1 6.1 |6.1 Vil 188 |191 ||239 |277 ||246 |228 Cr {I |||||.|| Ni lI ||||||| K/Rb |}|||||l | K/Ba ||||||-||| Rb/Sr I ||||||l all analyses by DGGS for J.Reeder;trace elements by C.Langmuir,Lamont-Doherty "Older Makushin Volcanics Eider Point Area M-32.-wt 2 Il M-30 J |5 |U-201-R-1* il t.{| Sidp tl 49.49 |49.43 }50.33 |48.74 Ti0p J}0.89 |0.92 |0.86 |0.85Alo03I]17.47 |17.92 |17.96 |14.69 Fes03 «IE:3.52 |03.90 =f 289 |2.44 Fed [}6.10 |5.72 |6.35 |7.11 MnO I}0.18 |0.18 |0.14 |0.19 MgO I!8.10 |7.34 7.24 {9.90 e CaO }1 10.98 |10.57 |10.44 |12.03 Na20 1}2.84 |2.80 |2.67 |2.34 6"/Ko0 jl 0.74 |0.78 |0.86 |0.69 / Po0s r 0:13 !0.17 |0.14 |0.18 HoO*I]0.23 [|0.68 |0.14 | H30_r 0.05 |0.45 |0.13 | total t 100.72 100.86 ||99.16 Fe0*/Mg 0 1.14 !1.26 |1.20 !0.94 trace 11 ||| elements |]||| -(ppm)11°:7 ||| K(x1,000 )If..6.1 [|6.5 1.7.1 |.7 5.7 Rb 6d || Bas {|227 |||210 Sr -s II 550 |||572 ta fl 8 |||6.8 Ce ff 13 ||| Nd Jl 8 ||| Y-[I 15 |||Zr =ft s51 ||| ,Nb lf 3.6 ||| Ti(x1,000)Jf 5.3 |.5.5 |5.2 |5.1 .Vv |]258 |||308 Cr If 130 ||| Ni Il 40.|||K/Rb -s ||695 ||| K/Ba sstLso27--s || Rb/Sr {ft 0.02 ||| *from Drewes (et al.,1961).4*analysis by DGGS for J.Reeder;trace elements by C.Langmuir,Lamont-Doherty dh.bad Older Makushin Volcanics raRedCinderDomeRidge M-34 TOONOADAMMROUWM,M Wo ot© IN RMONN HADOMNeR Oo [oe] oOo [oo] :ke eo e©©@@#@ e6 Cn) . . e e t oan Orsrd OTrTOmMmMooed oo a- [oe] © c=. wa ee fea) =] Nr tOnwoDOnrmwaWM LOetw© " 1 ee 66ee¢68#@© »® e . e '¢@ e8 e = OOnMNMOK ANDO O oo oO WARDMOMAETANW Ae TN OO weo toe © weetOILOetCae owt OdN mt Not Ne WO pefeeaDSeSEDASDNSSDOTHISONEEMemeomeYMNSeureeam}SSGOEDGEESSTOSGEDGOONS GEGENGDOSNSYGORENGEESGOREANNESGNDGENEGOONSCOSEDGerEEDORESCaSGEDGOES OY Ht MN Het tow esoO Ow eoom So 2 MANA AN DOHA eAtOnw Oo Ne]rn No] NS oe] i] ee e©©#©©@@#@@ ee oe«6 e e8 e =) eta nowonrwrnnO OO nA ™ MUWFAetme WM OWat© ©Co an SOct19AONIotAe fosmae] . ' +roO N KO ANDAM™AMOUOMU AE Ow ++ : we TOSTM™ OMAN LOON oo +©c ike) n eee6eeeescd e ee s e e se = NOON WOTAM etO(aoa>)anoo [oe] ive) wa n ' . ;LmaecnneaemeemmaomenseancomacaneguntcometnesSnannSNLeeSONYGSCOGeeeeSEeeteensSEREDSDGSEYGDSESODGSSe SSSDSRSeGamND ONUOEKEMAONMNAINM am ve) [oe] ' N i OMm M M ALON NW Ort oo ™ [oe] [oe] or oO e eeffaee.e ° e e e ee e aA ONnNWOTHM OO oo cOCoa WOMOWNUOAMNSETFTHWORITPTONM © wta fo) AOM Net NO om an LO N + KO NWWWAOMAOMm © (ono) oOmM xs 92) HMA MN etm OMN oOo + (o) e oOo i] o¢@@ ee ©@@© #8 @ ee «¢ . e o- e8 e >> MOMANMOATDAMAO oo nanea NOTMOoOwWMWwonrtw STDs AmKmO wo- n NWWWAAetNO Meta ON oO ew ton LlLastsfavesSanneomASD<mSDGomcint)necessusSLATEDGxnmheNYOOMNLENSYGommeSOE?SAEuneSOSCDSDSSDESDSOSSSNODSSNDSSSDSDEDEDSEEDGNDSDGULo OM OerTwWoODMDADMDAMAO on - fon) mr) THAON OM WOM STON oo + = n ] .e e o ee ee @e¢ e «@ e e e e e = NOONWOTHAMOO oo an- foe) w iote fon) : fefareSRSSRDSESeGNSSSDTSSeOESEDGSGEESSSGD GS AEDEDGDOTDSTNGEEGEDSEESGREYGEEGaGDEDGEGeSERNREEDGERENGEEeeGm SeMAHAADWODM™ WHAM CO On oOx co WOetaAn NANO WOW (ana)anOo nO i.oO oO eee°eeeee ° ee e *° ee e Net OnNWODTOMA O oo fo) ton AOMUMMEAMLM STWDOMOWO Loo oO g AMMAN RKND nN con MWe N Lo fafaeaeeeinseneemeresea eeeeceeeeeet ee ee ceea eeeeacseeareee PeaeaeeeceaeSeeeeeeee eeNYee SE SE SSNYNYSYNSSYCESNSnDceeCoeeencomme ar] -_ bY mo V-_ mn " fo) NNO © oS to+' fie] "= oH ONG kK CVT &AO> Le Oot& ¥CON NOO0C0 NOOO oo »= VEROCMANYHOSZ N=O Oontzarenn mmm VO OWAIA QLAI °*-COVA oa © MS Oe DCW ae mom <a popeon- [o) SGeee . a" stOo oO Homex a! a Lo roww *< ced] aZ a== Cr Anteae en re ee Older Makushin Volcanics myray:ansPointKovrizhkaArea nr a 4 Ul panes OeEYeS ee OtloreeeMet©eymonNIAENeeeMAOmatoOoOedeeemHOMOsipWwnneeeMAOOmWwtHee.eMoomtOoomeeeeMHAOfom] Fe)NO©TMS AIN.= . Fe0*/Mg0 trace elements PoeSetaGNSRCEGENDODGNKSETEGESTSGESGEOEeeaeeeeeeeee(ppm)aASEASAASSTGESmGoNDODGONGSUNASEDGEAGUTGTSGNDGEDGeeeeeGeSSmepeeGmemtGeenGOESGenKeneD GEESSEEDGIRSGRYGEESCometGameei Ae cc SaaD DD tresCNemGEDTTSEESGEDGDGEDSANDeTmAREEDGEEEDSONDTEEDEDISEDGEESGREEDGENEScagesGeGREEDGERENneGanenquGED N wo an oO e . ° e ™ ALM OM [a0] =o amOMmM otot (ooan! srl \O f. to ot wm So e . e ° TOwWnKeMOM vs +o ANON AM On rc w WN [a] MmoO oO e ee eODOWMWMNHnOADAADMMMWWMWHO mae to eHetiWO WONre : WN NJ wo foe) (ve) fd °. foe) ire) WN Oo ot [a] e ee eOwNwAMOATrTwMOTAMUMOWMOO aH MM Net AO Ore rrm©$ : orm NW! ve) rt N e e © wo iw [oe] Mmwo oO e ee °NOAMOWPOW ANDAMAN MAAHO AN tO KIMAtAID OoMm mMuA Ss.0 a WN s+ - oOo -_ DA GCL OVUS LNOO> LeA kt OF NNO ™N=© Oza non a Oo ™.S ea « <3AO bad = - «< aZ eadSaade Xfrom Perfit (1977) Older Nakushin Volcanics Mt.Marshall Reese Area ' WHT NES NetetetON i wt w -) oe e@ ee ©@@©©@©@ ° ) , e IN OomamnnoranmMmMoo N ce No won 'Ww4 fo.sS| La pO NIWO iN] P=pene PUTSCtEDEDSNEGUNSGEESERINE eeeAMENDGULGND eoUoeED tSGee)GETSUNNGEEGEGee GRANND GUEGOESGUTSGSES GENES SEES) Gute geneteeeeeeSEDGeessieGeeeeOeoeoeoefame[ReeSUSSDSRSGENESLNDSENSCUSSUESSUSGDSomSODTSSSENETSOSGESSESGESGEeSmSSRDGESTSSETTDGOEDGmMEESGETENCREDGEEEDGEEEIOGEREN)GUENSGREEDREGREEDGEDGEDGENeEeSOONDNKRORNHAMst MEM Lg MNMNNnNODOIAMmMAWOMet s+in w iw pee) ee ee © e@ #© &® 8@© e . . ° e AOMAMWOMONDO oo ae oO wo wo tom ; to] : aDS CS GaGeeGatCESDGESGDGETEDSSGee eeeet GeesGeeGsGEGeen BeesSeeomeGeeseeeleSeeeeeeeeteeeeeeeeeeeeeeeeeeseeeeeoe eh.. \ JafemmeensenareeeeSettweeeeeaaceSDNYSY eS NSeSSeSENSMDSYNDeSSDMnSYeSnsmseSEGocum”Somme WO, MTOOTRRANNNO DO WNOO 0 ot WOW PHA ARON MA +o wOo N aN oO ' eeoe.eee°e° ee e e ' e@ ee e EI, MAOMMONDMADG O29 DD ww ANE TROADMUWOWUOAMtOO w- rn AMNOMN KINN imnAmMmwom os ot N [oe]paceaRERESeSEERUESOGTONSSOSGiNDGONSNeGRASGYGoSSGOGoRSDGNDGENESGANTQEDGHNESSRONGENSOODGEESSOAKSESSGSGSESGDOESGEESGmwr AM Det AN Am WOO wore oO ht OOwWwtT eH HOM TON +cO a + i °e° °e°ee ®e e e e e c= wownrorsT Orn ™Mno oo OQwt m wo uw (om) e _feaeSeCSeeSYRYSnDcSSTSEGOOEDONSSDSNDSDNDGSSSSENDENGERENGeNDSSUTSGEDSNSGLEEGEDwennGESCYGOMESEEGROTENDGemOESSNESEEGMESDIO OMm rmret tm NOME am o ed want WONDOW HN HFWwOMmnAe Aw Oe fos) s to] [oe] ' .eee°ee®e«° °e e . e e = MONnNWOTOMAO oo (3.0) - N w Ww wot n mt. peeeeeeoSSSNSDRDRE ESSESS ST ON EYSSA ES SS SC CRISNSDODSEESe"OWNNORWODRHO CO wo + a KO NOMYN MAN DTMWUO AN oe Na in rom oO 1 ee°eee°eeee ee . e e °° e pa TeaIm MwMOowsoMneod oo oOeo NWMW MAND etdm Ont OUMAO woro vn ANNO ANMNAM Ss PTuHoOAFON \ ++ aei)o OAODOTtMNUOMOASTWOON. Oe ws [oe] c aa ONnTN MOMet tong Ore oO [oe] (oe) ND oO 1 °.eeeeee°®° °° ° e 76 e. « c= MOoOMnMMOTDMRHO oo (oa) ea NPFNOPAANDWWOMNANDAWOO w7 coy) AIM ANAM AH TLOAwWM oo et N ra)PefacecometSSSnSGoDSESGEONGASeGSDSEEDGONESRTSSOSceeSUTESNDSSGESDSSGEENSESGENTSESEYSEKSDGSLENNYGUSUDGEOUNDWSOSpeefeesSDSSRETDSECTSASINSSeeSEESGREEPSCEDGENESuemOSGomiSEESpmensSeeD EDSaNPSNSGEDGEGERDOEEGEDGEELNNSSESESODGDSSGS & oO _ : CAMs = m wv fan] - NNO © So Lo+'©= VHP LOO GPK DUVUSY LDO> here OOh $ DANNO COCO NOOO oo ed - VU C'GFOMNNHOS NZzO Oz Aeanawn meme VV CMO OWNA NOI oO* owA,a Oo Oe ti wetrowzxwa xx » (o>) &GGaqet a M2 owPotx - (a LL ec - < rob] aZ ew-r CDE GO Bk STILEeeotthe +from Drewes (et al.,1961) "*analysis by DGGS for J.Reeder;trace elements by C.Langmuir,Lamont-Doherty |U-203-R-/*18*heLLGM-44a |wt% Older Makushin Volcanics >Swvont(o) 1 Q i ! , Ce ' ce NOME LOO Det WOAIO fo) mM| © WOODAMNMANAWNMmEM wsN in oad) seeeeeesCyee e ° . e NreAtwondwWonW er4© 2 - LsAIco On a wet OQ edNsf wt $. : ce wom P| Coal= Se, fo Ln BN.aww L r=] NOTMWHOMNAN Net wn + n _ see.e6eeea.e e. e e OOWMNMOMUNMNO oo N iaa t+ ° et oO> aeSeeGeGoNDSEGEeSeSSDENeosOHNEOOemseSSY ne eeeSSES YS EDSS SDSSGeSSeeeSee Q , " co on NN wn t re) *aoe ee e e HHOAIMOMOISS oo N [oe] la & t eC eaSerSAcenaweSeeSNSGSemGSSTSGtSeSSSeeDGDSEEeeesGe)GS SOeSeeeeSSSSS DS eeeeSeSeeeeee wa wo x aA Wx fon) oO ADM MNNAAOATAGO es rte Ls mo o eo ee@@eee eo8o 86 ee e e e OOuMTONDNONOO oo Oo wOa on-g- FameqareceSAEomeGEaeSDSEoneceeSSGmGSSESSENSemSScaeSEOSGEGESONSSNSUREGENUSGSES STEGEDONESDSSSNeSSSSYSSee wvnw)(oF)re) ormnon todraonwnm On =< lo Cal [ag metetetQINAftOOan on re = <r€ Oo Oo *'@ eLZeeeeeeee e. e s eo e nN e MAMAMUOOTADAMAO oo WN NON OADWDDAOMMUOMMOOMDAO-_ La] Ww an! NON SN AMA WON AON : s+ot et WN x « t. . (oe) LesemSNSSAOGeSASSReeeRD DSenSDeytensESnSeycsMenSOcerteeensSeSScesne SD Semoteeeeeecseseeeeee aePa© NMMOTHANOMITRIN WIN ” \ Py oO NOwodOrnt Oowwrdne Ost [oe] N WN wvOo oe @¢ © ee @ #* ®* #@ @°@ eo c) ° e - a Hi DOoMaomMnonmnoo oOo - fe) +4 aan %,)>wv2 e = ey wo" LoneSaneoeSSSESeSESSaeSS De Se aSeSeTSOeeeeeeeGSSSSNEGeSNSNSNDMENGereGSSENSGEeeneSGYeee a rs) : Pabr mo oO = -_ s. > NNO © oO Lob i)= mn on fo) fo] AOY Ea QDONNODOOQO NOOO oo Lie] = OPA O oO aan™m [e} ie] mre VVEDVG NAN NN PP MN sec bBOn siBCOU LaAO Lor SSO oc MONre Caw Serostzwa bsaoeomfo)* KV ere MNndOw NZ 8h?OSZ M«MM-ME Ge os owoO YE Ae ro +« w ao"x « tne tcoed - net eB) x - - Satellite Vents Pakushin Cone wt Z|M-20 |M-2l T U-58-S-1*[7 |U5-154H* T .I |T Silo |55.34 |50.92 |55.61 }51.13 |49.73 Ti0>|0.90 |0.94 |0.88 |0.88 |0.97 Alo03 |19.87 |18.95 |19.77 |18.32.|22.16 Feo03 |2.34 |3.21 |2.99 |3.30 |.9.63 Fed |4.66 |5.59 |4.82 |6.02 { MnO |0.17 |0.18 |0.18 {0.18 |0.18 MgO =|3.05 |4.99 |4.04 }5.94 |7.70 Cao |8.45 |9.28 |8.22 |9.46 1%6.17Naz0|4.19 |3.28 |3.56 |}2.96 |2 2.42Ko0-|1.48 |1.14 |1.42 }1.01 oy 0.19Pos|0.24 |0.19 |0.27 |0.18 id 0.12|H0*|0.00 |0.09 ||0.29 | H50_|0.02 |0.07 ||0.07 |.| total 100.71 !98.83 |101.41 !99.85 !99.27 ° Fed*/Mg0 !2.22 |1.70 |1.86 |1.51 !1.25 trace ||||| elements ||||I (ppm)|||||. K(x1,000)|-12.3 |9.5 {|11.8 |8.4 '|1.6 Rb |20 |16 -||=| Ba |402 |327 '|374 |] Sr |715 |693 |703 || La |11 |7 ||I Ce |28 |22 ||| Nd |17 }13 ||| Y |23 {19 |l I Zr 94 |72 ||| Nb |5.0 [|4.1 |I | Ti(x1,000)|5.4 |5.6 |5.3 1 5.3 |5.8 v |234 =-=«d:s35 |220 || Cr |17 |50 ||| Ni |8 |}18 ||| K/Rb |604 }615 ||| K/Ba_|30 |29 ||I Rb/Sr |0.03 |0.02 ||| *total Fe as Fed *analysis by DGGS for J.Reeder;trace elements byC.Langmuir,Lamont-Doherty °from Drewes (et al.,1961) . Xfrom Perfit (1977) Satellite Vents Pakushin Cone U5-154H*wt Z 1 M-20.|M-21 T U-58-S-I*J 7°| |T ||| Si0g |55.34 |'50:92 |55.61 }51.13 |49.73 Ti0g |0.90 |0.94 |0.88 |0.88 |0.97 Alo03 |19.87 |18.95 |19.77 }18.32 -]22.16 Fe503 |2.34 |3.21 |2.99 |3.30 |9.63* Fe |4.66 |5.59 |4.82 |6.02 |. MnO |0.17 |0.18 |0.18 |0.18 |.0.18 MgO |3.05 |4.99 |4.04 }5.94 }7.70 Cad |8.45 |9.28 |8.22 |9.46 |-6.17Naod|4.19 |3.28 |3.56 |2.96 |-,2.42Ko0|1.48 |1.14 |1.42 }1.01 .-|#0.19Po05|0.24 !0.19 |0.27 |0.18 V 0.12H,0r |0.00 |0.09 ||0.29 | H>0_!0.02 |0.07 |!0.07 | total |100.71 !98.83 !101.41 |99.85 99.27 Fe0*/MgO !2.22 |1.70 |1.86 |1.51 1.25 trace ||||| cTenents |||| |||||K(x:560)}.12.37 |9.5 |11.8 |}8.4 |1.6 - Rb |*20 |16 ||-| Ba |402 |327 |374 || Sr |715 |693 |703 || La |11 1 7 ||| Ce |28 |22 ||| Nd |17 |13 ||[.Y |23 }19 ||| Zr |94 1 72 1 || Nb |5.0 |4.1 ||| Ti(x1,000)|5.4 |5.6 1 5.3 |5.3 |5.8Vv|234 |315 |220 || Cr |17 |50 ||| Ni |8 |18 ||| K/Rb-|604 ]615 \-|| K/Ba_|30 |29 ||| Rb/Sr |0.03 |0.02 ||| total Fe as Fed: *analysis by DGGS for J.Reeder;trace elements by C.Langmuir,Lamont-Doherty °from Drewes (et al.,-1961) Xfrom Perfit (1977) Satellite Vents SugarloaTableTopMtnConeWideBayConePt.Kadin. é wt&%1 co wtatOVLO 22) [oe] MNLOoOLO N Ww of mM 6 NI °.ee.ee e e e . a) e t NOWMPOWANDO aSo - >+ mw ep eos ° 8 s = f [oe] fon) NCO ov wo WOWNN TAOWWMme tO eq oO Kk *@¢ @#e#® @© ee@@ ee e e e a NOWNMNOoOOMANOO oo om oO wo Laan! 7 -eemeomeeeeoneeeeeeeeeomGeeeeoD ReeeCSGDSUTLDNESTSSAYGDGDmEcam 0Os MOmAaM OWWAAIM O OoN ' OornrMetaNomMne ir) tas] we w " We) eoeeee.eeee e e e e e a HOWMOODNNOO ©rot io]tmwo© w rant rrot &Qc fon) NE ' Me 4 Nw -- =A fr "s 0 MONDWDOHONRONND uN © ° TNOOANMMMNWON io) - ine) WN Kv) oo #@# #© #@e6 oo ee 6@ . e . e e ' NHNHsOnNWOONW tA© a ise) * AWwo Mm KOwWct n otettO ' * we Cel =) A AMMO KAA HFOOMMW Os [oo] - et > NNWMOON NW OMA on \OWw N >at ee ee .e ee e ee s e ee e t DNeHtOnNwoonwdaO oo [oo] mM trtTorTonmrneONMeaAMOWOMmcstSP. AM© =wo Comal (on) AMNMN AMON SM rmN -wom Ca] ei mo ve) oO woo loose) o bal ODOM ON SN eMOW tO wo [oe] KY) e os @ @© @® #@ @@ e e8 e . e NOoOMeMmWMOU ANOS oo te wo w >= toeeHer;'cx? NOoOmematNANOMmMANA We) * ' DNDWOWHOMMAN oOw co +st+oOo [oe] cv) oo ee ## @© ©8#8@ e e e QIWOet ° momrTMoOwWUANODO ron) ea Oo NW LOwd emtst- vt oO wo ' * a)and Pomme teOHO femHOet oo Ww rr NI MHWMOWMU HA KHtOMWON oOo oOwn ei Oo t °° ¢© #@# #©©© @© @© o oe ., e e e =| coOoOoertOMNHNOO CoO of! les ss in s+ - = oO NNO © oO wo+U- mn VvuUus Oo Oo AON CONNDOCONDO 00 6= CHES ro) co m =r = YVUCMO VMNN OLA pb CAO GK BYU &OO Ler0 Ore Caw eT EromMwa Te Oo* BU YO MNAOZ NS sreosezuwue P Oo PEW| a (+B) co)*« < lo toad -- ce)MZ Pa Lamont-Dohertymuir,tanalyses by DGGS for J.Reeder;trace elements by C.Lang *from Drewes (et al.,1961) "LS 9 ReeectsDareAeeneacaoa'Appendix II M-3 Lava flow of gray,porphyritic andesite.Phenocrysts form 34 percent of the rock:27 percent plagioclase,4 percent augite,3 percent hypersthene, trace amounts of olivine and opaques.Groundmass consists of plagioclase, pyroxene and opaque microlites in a matrix of devitrified dark-brown glass. H-4 _be i Lava flow of light gray,porphyritic basalt.Phenocrysts comprise 39 percent of the rock:30 percent plagioclase,4 percent augite and hypersthene, 1 percent olivine and opaque.Holocrystalline groundmass of plagioclase,- pyroxene and opaque. 1-6 , Lava flow of slightly oxidized,light-gray,porphyritic andesite. Phenocrysts of plagioclase (47 percent),augite (3 percent),hypersthene (3 percent),opaque (1 percent)and a trace of olivine comprise 54 percent of the rock.The holocrystalline groundmassis composed of plagioclase,-__ pyroxene and opaque. M-10 Lava flow of gray,porphyritic andesite.Phenocrysts comprise 30 percent of the rock:20 percent plagioclase,6 percent augite,3 percent hypersthene,1 percent pigeonite and a trace of olivine and opaque. Pigeonite rims some hypersthene grains.Holocrystalline groumdmass composed of plagioclase,pyroxene and opaque. M-14 Lava flow of brownish-gray,porphyritic andesite.Phenocrysts of plagioclase (20 percent),augite (6 percent),hypersthene (4 percent), olivine (2 percent),pigeonite (1 percent)and a trace of opaque comprise 33 percent of the rock.Pigeonite forms rims on hypersthene.Carbonate and clay minerals replace some of the mafic phenocrysts.Holocrystalline - groundmass is composed of plagioclase,pyroxene and opaques. i Lava flow of brownish-gray,porphyritic andesite.Phenocrysts comprise 33 percent of the rock:18 percent plagioclase,7 percent hypersthene,5 percent augite,2 percent opaque and 1 percent pigeonite.Some hypersthene grains have rims of pigeonite.Clay minerals have replaced some of the mafic phenocrysts.Holocrystalline groundmass is composed of plagioclase, - :pyroxene.and opaque.- = M-19 Lava flow of gray,porphyritic andesite.Phenocrysts form 45 percent of the rock:33 percent plagioclase,7 percent augite,2 percent hypersthene, and 1 percent each of pigeonite,olivine and opaque.Pigeonite forms rims on both olivine and hypersthene.Groundmass consists of plagioclase, pyroxene and opaques in a matrix of dark-brown partially devitrified glass. M-20, Lava flow of gray,porphyritic andesite.Phenocrysts of plagioclase (40 percent),augite and hypersthene (3 percent),pigeonite and olivine (0.5 percent),comprise 47 percent of the rock.Olivine has rims of pigeonite.Plagioclase is glomerophyric.Groundmass contains plagioclase, pyroxene and Opaque in dark-brown glass. M2 , Lava flow of dark-gray,porphyritic basalt.Phenocrysts compose 50 percent of the rock:39 percent plagioclase,6 percent olivine and 5 percent olivine.Plagioclase forms glomerocrysts.Groundmass consists of plagioclase,pyroxene and opaque in dark-brown glass. M-27 --Ly f Lava flow of reddish-gray,porphyritic basalt.Phenocry sts of plagioclase (37 percent),augite (7 percent)and olivine (3 fercent)comprise 47 percent of the rock.Many of the olivine grains are rimmed by opaque, some grains show a sympletitic intergrowth of olivine and opaque. Holocrystalline groundmass is composed of plagioclase,pyroxene and opaque. M-30 Lava flow of gray,porphyritic basalt from the ridge between Table Top and Wide Bay Cove.Phenocrysts compose 45 percent of the rock:28 percent:-- plagioclase,9 percent augite and 8 percent olivine.Groundmass is a holocrystalline mixture of plagioclase,pyroxene and opaques.ey M-32 Lava flow of gray,fine-grained,microporphyritic basalt from the valley between Table Top and Wide Bay Cone.'iicrophenocrysts comprise 33 percent of the rock:plagioclase 21 percent,6 percent augite and 6 pecent olivine.Groundmass is composed of plagioclase,pyroxene and opaques. Serpentine has altered some of the olivine and the groundmass. M-34 , -- Lava flow of reddish-gray,porphyritic basalt.Phenocrysts comprise 34 percent of the rock:31 percent plagioclase,3 percent augite and a trace of pigeonite.Pigeonite rims some augite.Groundmass consists of microlites and dendritesof plagioclase,pyroxene and opaques in brown glass. M-35 -_-_-- Lava flow of gray,porphyritic basalt.Phenocrysts comprise 38 percent f of the rock:.33 percent plagioclase,4 percent augite and 1 percent olivine.iad aaGroundmassconsistsofplagioclase,pyroxene and opaque micrélites in brown glass. M-36 Lava flow of gray,porphyritic andesite.Phenocrysts comprise 35 percent of the rock:30 percent plagioclase,2 percent augite,2 percent olivine, 1 percent pigeonite and trace amounts of hypersthene and opaques.Groundmass is a holocrystalline mixture of plagioclase,pyroxene and opaques. 4-37, Lava flow of gray,porphyritic basalt.Phenocrysts comprise 36 percent of the rock:29 percent plagioclase,4 percent olivine,3 percent augite. Groundmass consistsof plagioclase,pyroxene and opaques in brown,microlite- bearing glass. M-38| Lava flow of light-gray,porphyritic basalt.Phenocrysts comprise 52 percent:plagioclase 45 percent,augite 5 percent,hypersthene 1 percent, opaques 1 percent and traces of pigeonite.Some olivine phenocrysts are rimmed by clinopyroxene.Groundmass is devitrified brown glass with plagioclase,pyroxene and opaque. M-39 Dike of black,.vesicular,porphyritic andesite.Snarse (3 percent) phenocrysts of plagioclaseand a trace of augite ina groundmass of plagioclase,pyroxene and opaque crystals in brown glass. M-40 Lava flow of very light gray,porphyritic basalt.Phenocrysts compose .f 32 percent of the rock:20 percent plagioclase,7 percent augite,5 percent:1. oliving and a trace of opaques.Holocrystalline groundmass is composed of plagioclase,pyroxene and opaque. M-42 Lava flow of brownish-gray,altered,porphyritic basalt.Phenocrysts compose 43 percent of the rock:34 percent plagioclase,6 percent augite and 3 percent olivine.Groundmass is a holocrystalline mixture of plagioclase,- « pyroxene and opaques.: + M-43a Loose block,black,vesicular,porphyritic andesite.Phenocrysts _ compose 13 percent of the rock:10 percent plagioclase,2 percent augite, 1 percent opaque.Groundmass is composed of plagioclase,clinopyroxene and opaque microlites in a brown glass. M-43b Loose block,black,vesicular,porphyritic andesite.Phenocrysts compose 13 percent of the rock:11.5 percent plagioclase,0.5 percent augite,0.5 percent hypersthene,0.5 percent opaques and trace amounts of olivine.Groundmass is a mixture of plagioclase,opaque and pyroxene (?) microlites in a light-brown glass. M-43¢ Loose block,black,flow-banded,porphyritic dacite.Phenocrysts compose 15%of the rock:14 percent plagioclase,0.5 percent augite and 0.5 percent hypersthene.Groundmass is mostly brown glass with a few dendritic microlites of plagioclase,opaques and pyroxene {7?). LS N-43f i-_-_-_- Loose block,dark-gray,porphyritic andesite.Phenocrysts compose 13 percent of the rock:11 percent plagioclase,1 percent augite,1 percent hypersthene and a trace of olivine.Groundmass contains microlites of dendritic plagioclase,pyroxene and opaques in brown glass. M-44a Small plug of gray,porphyritic basalt.Phenocrysts comprise 38 percent of the rock and consist of 33 percent plagioclase and 5 percent opaque.'The ) opaque phenocrysts probably represent oxidized silicates.Hypocrystalline groundmass contains plagioclase,pyroxene and opaque grains in a colorless awaglass. M-44b Loose block,dark-gray,Flow-banded,porphyritic andesite.Phenocrysts compose 4 percent of the rock:°2 percent plagioclase,1 percent hypersthene, and 1 percent augite.Groundmass consists of light-brown glass with microlites of plagioclase,pyroxene and opaque. M-44c Lava flow of pinkish-gray,porphyritic andesite.Phenocryst of plagioclase (21 percent),augite (4 percent),olivine (2 percent),opaque and hypersthene (each 1 percent)constitute 29 percent of the rock.The hypocrystalline groundmass contains plagioclase,pyroxene and opaque crystals in a light-brown glass. M-45 Lava flow of gray,porphyritic basalt.Phenocrysts comprise 30 percent of the rock:14 percent plagioclase,7 percent augite,5 pecent hypersthene, 3 percent olivine,1 percent pigeonite and opaque.Rims of clinopyroxene -are found on some orthopyroxene grains.Groundmass consists of plagioclase, clinopyroxene and opaques. . Lava flow of gray,porphyritic basalt.Phenocrysts comprise 29 percent of the rock:21 percent plagioclase,5 percent augite,2 percent hypersthene and 1 percent olivine..Holocrystalline groundmass composed of plagioclase, |pyroxene and opaque. M-47 Lava flow of light-gray,porphyritic basalt.Phenocrysts comprise 27 percent of the rock:26 percent plagioclase,1 percent olivine and a trace of augite and opaque.Plagioclase is glomerophyric.Holocrystalline trachytitic groundmass composed of plagioclase,pyroxene and opaque. M48 | Lava flow of light-gray,porphyritic basalt.Phenocrysts compose 56 percent of the rock:47 percent plagioclase,8 percent olivine,1 percent augite and a trace of hypersthene.Some hypersthene grains have a rim of clinopyroxene.Fine-grained groundmass is composed of plagioclase and pyroxene. M-49 Lava flow of gray,porphyritic basalt.Phenorysts comprise 47 percent of the rock:46 percent plagioclase,1 percent augite and a trace of - olivine.Groundmass contains pyroxene dendrites,plagioclase and opaque in brown glass.--_- M-52 Samplé of agglutinated spatter-on crater rim.Black,porphyritic andesite.Phenocrysts compose 2 percent of the rock:2 percent plagioclase and a trace of augite.Groundmass contains plagioclase and opaque ina Base light-brown to colorless glass. M21 , Lava flow of dark-gray,porphyritic basalt.Phenocrysts compose 50 percent of the rock:39 percent plagioclase,6 percent olivine and 5 percent olivine.Plagioclase forms glomerocrysts.Groundmass consists of plagioclase,pyroxene and opaque in dark-brown glass. M-27-_--.r Lava flow of reddish-gray,porphyritic basalt.Phenocrysts of plagioclase (37 percent),augite (7 percent)and olivine (3 fercent)comprise 47 percent of the rock.Many of the olivine grains are rimmed by opaque, some grains show a sympletitic intergrowth of olivine and opaque. Holocrystalline groundmass is composed of plagioclase,pyroxene and opaque. M-30 | Lava flow of gray,porphyritic basalt from the ridge between Table Top and Wide Bay Cove.Phenocrysts compose 45 percent of the rock:238 percent.:. plagioctase,9 percent augite and 8 percent olivine.Groundmass isa holocrystalline mixture of plagioclase,pyroxene and opaques.a M-32 Lava flow of gray,fine-grained,microporphyritic basalt from the valley between Table Top and Wide Bay Cone.'Wicrophenocrysts comprise 33 percent of the rock:plagioclase 21 percent,6 percent augite and 6 pecent olivine.Groundmass is composed of plagioclase,pyroxene and opaques. Serpentine has altered some of the olivine and the groundmass. Lava flow of light-gray,porphyritic basalt.Phenocrysts compose 56 percent of the rock:47 percent plagioclase,8 percent olivine,1 percent augite and a trace of hypersthene.Some hypersthene grains have a rim of clinopyroxene.Fine-grained groundmass is composed of plagioclase and pyroxene.r Lava flow of gray,porphyritic basalt.Phenorysts comprise 47 percent of the,rock:46 percent plagioclase,1 percent augite and a trace of olivine.Groundmass contains pyroxene dendrites,plagioclase and opaque in * brown glass.-_ M-52 . Sample of agglutinated spatter-on crater rim.Black,porphyritic andesite.Phenocrysts compose 2 percent of the rock:2 percent plagioclase and a trace of augite.Groundmass contains plagioclase and opaque in a light-brown to colorless glass. ALASKA POWER AUTHORITY-INTEROFFICE ROUTING SLIP=DATE__ osCc)_) OATE TNE TIAL DATE INITIAL REMARKS EXECUTIVE DIRECTOR,ERIC P YOULD GOARD LIAISON,M.BISHOP Ov.STAFFORD Ov.FERGUSON ._|PUBLIC INFORMATION OFFICER,G.GLEASON '|CONSTRUCTION DIRECTOR,J.PERKINS (0.EBERLE OG.RANSOM Ov.LONGACRE OG.LARSON \ ENGINEERING OIRECTOR/SUSITNA PROU.MGR,R.MOHN OT ARMINSK!I {J &BEDARD VJ OR.FLEMING OC.JONes WA DO v.SAARINEN CO B.PETRIE raDD.WOZNIAK O R WILLIAMS Lo FINANCE DIRECTOR,R.BENISH OG.MANNI C)T.ANDREOLA O Cc.HUSEMAN ()#.NOONAN O LBalLey Ob.RIeTZeE »O L.HAYES O R ACUFF PROJECT EVALUATION DIRECTOR,RP DeJONG YAOT.LESNIAK C)N.BLUNCK OO E.MARCHEGIANI O C.THOMAS SYSTEMS PLANNING &OPERATIONS DIRECTOR,M.YERKES OL.WOLF QO) LIBRARY/FILES WwJniversityofAlas..a wie PETROLEUM ENGINEERING DEPARTMENT yeROOM17,DUCKERING BUILDING gl. FAIRBANKS,ALASKA 99701 PETROLEUM ENGINEERING (907)474-7734 hepu ”3 faeElves fe oom 23 1923CLiISKyPuyinyaaUARMay18,1983 STH CRIT Ms.Patricia DeJong Director of Project Evaluations Alaska Power Authority 334 West 5th Avenue Anchorage,Alaska 99501. Dear Patti: Congratulations on the new title.Have you had it for a while? I have received the Republic Geothermal Report and I will submit a critique to you by May 25,1983. Following a recent telephone call with Roman Motyka informing me on an agreement with you I presume that any outstanding issues regarding my supplemental RSA have been ironed out.For university budgetary purposes I would appreciate it if I were to receive the document before July 1,1983.You would oblige me if you could respond to this request. Best regards. Sincerely, Michael J.Economides Assistant Professor Petroleum Engineering 38 97.a2 UNIVERSITYOF ALASKA,FAIRBANKS " Fairbanks,Alaska 99701 September 4,198] -.-be [oo feaon Yog sfMrDonMarkle,Projects Manager Yo >- Division of Energy &Power Deve lopment7thFloorMcKayBuilding 338 Denali St. Anchorage,Alaska 9950] 'Dear Don:a oS,'The'Morrison-Knudson report on the Unalaska geothermal developmentarrivedhere-last'fonday.AS you have requested,I read it and then called Ms.Sue Spencer and offered her my critique on the report. ao Let me offer to-you (in-much blander fashion)my comments: The report has severe flaws. Their estimation of the resource is not only inadequate,it is out- right faulty.Nowhere in the world does a geothermal resourcedependonmeteoricwater.Their evaluationof the rainfall and,i hence,of the available geothermal fluid shows a lack of familiarity with the mechanisms prevalent in geothermal reservoirs.Basic heat transfer calculations can show that the rate of heating from \the magma body to the geothermal fluid (via conduction)is orders\of magnitude slower than the rate of cooling (via convection mixing) i that should occur if meteoric water were to find its way in the reservoir.aleAll geothermal reservoirs are considered closed systems and that3theinhabitingwateriscertaintohavebeenheatedforseveral4thousandyears.Recharge from colder.formations is never considered*is in reservoir evaluation.Den .WINeoeoOHome_*&weespeei 3 While it is true that most of the heat energy (7/8)would be foundintherockmatrix,reinjection of spent fluid (to extract more of the resident heat)is not always successful.This is why both the Italians and the New Zealanders do not attempt to devise massive reinjection systems.They dispose of the water either in adjoininglakesorstreamsortheyreinjectitinformationsthatareseparatedbyfaultswiththeworkingreservoir.They want to avoid fast fluid /™ "breakthrough"with the resulting disastrous.formation cooling, N :<i - €sothermal-is;contrary to theAlaskan folklore,largely &nan-renew=)<<_(7 <=able,depletable resource.aanSsaeil<2.Their economic study fails to compare various sites of geothermal and diesel power plants.While at low MW values,a geothermal power station will undoubtedly prove more expensive and unattractive a \ UNIVERSITY OF AI iKA Page 2 a,-« /(due to heavy logistical and drilling/construction costs);at higher MW values it eventually meets the diesel curve and finally becomes more attractive.That joint can be found,hence,the design of a geothermal power plant must take into account this level whichmustberelatedtothe_present and future needs on Unalaska.This otisthesubjectofGurpape)to be presented in the New Zealand Work-- ashop.|: Finally,the number of wells that the M-K report claims that are needed for the case study of 30 MW is double the real figure.One MW of electricity requires 20,000 Ibs/hr.Hence,a total of 600,000 lbs/hr.would suffice.Three steam wells of 200,000 lbs/hr. each are needed.Even with a 50%dry-wet ratio (which is very con- servative),the drilling costs would be markedly lower than the ones quoted by the M-K report. The above are the most obvious things that come to mind.Let me know if you need a more detailed critique. MJE/bs.- Sincerely, Michael J.Economides Assistant Professor Petroleum Engineering PLEASE REPLY BY AIRMAIL