HomeMy WebLinkAboutPreliminary Geological Evaluation-Naknek AK Geothermal ResouNaknek Electric Association I , -- I,&, 7 Society for Sedimentary Geology mm.seprn.oq I -r4 -
PRELIMINARY GEOLOGICAL EVALUATION
NAKNEK GEOTHERMAL SOURCES, ALASKA
HDL 07-302
September 13, 2007
Lorie M. Dilley, PElCPG
Principal Geologist
3335 Arctic Blvd., Ste. 100
Anchorage, AK 99503
Phone: 907.564.2120
Fax: 907.564.2122
TABLE OF CONTENTS ......................................................................... 1.0 INTRODUCTION 1 2.0 BACKGROUND AND GEOTHERMAL RESOURCE CHARACTERIZATION ............................................................ 1 2.1 LOCATION ............................................................................. .l 2.2 GEOTHERMAL SYSTEMS.. ......................................................... 2 2.3 GEOLOGY ............................................................................. ..3 2.4 HYDROGEOLOGY .................................................................. -1 0 3.0 NAKNEK ELECTRIC ASSOCIATION STUDIES ............................. .12 3.1 SOILSAMPLMG .......................................................................... 12 3.2 GEOCHEMISTRY ..................................................................... 1 6 4.0 GEOTHERMAL POTENTIAL .................................................... 18 5.0 CONCLUSIONS ........................................................................ 19 6.0 LIMITATIONS ........................................................................... 20 7.0 BIBLIOGRAPHY ........................................................................ 21 Figure 1 Figure 2a Figure 2b Figure 3 Figure 4 Figure 5a
Figure 5b
Figure 5c
Figure 5d
Figure 6a
Figure 6b
Figure 6c
Figure 6d
Figure 7a
Figure 7b
Figure 7c
Figure 7d
LlST OF FIGURES Vicinity Map Site Map - Topographic Site Map - Political Geologic Cross Section GIs Map Legend GIs Map - NEA Testing Sites - Landsat
GIs Map - NEA Testing Sites - Geology Overlay
GIs Map - NEA Testing Sites - Magnetic Anomaly Overlay
GIs Map - NEA Testing Sites - Bouguer Gravity Anomaly
Overlay
GIs Map - Naknek Region - Landsat
GIs Map - Naknek Region - Geology Overlay
GIs Map - Naknek Region - Magnetic Anomaly Overlay
GIs Map - Naknek Region - Bouguer Gravity Anomaly
Overlay
GIs Map - Alaska Peninsula - Landsat
GIs Map - Alaska Peninsula - Geology Overlay
GIs Map - Alaska Peninsula - Magnetic Anomaly Overlay
GIs Map - Alaska Peninsula - Bouguer Gravity Anomaly
Overlay
LlST OF APPENDICES
Appendix A Jim Cough's Report on the Naknek Core
Appendix B NEA Soil Sampling Locations and Notes
Naknek Electric Association HDL 07-302 Preliminary Geological Evaluation Naknek Geothermal Sources. Alaska PRELIMINARY GEOLOGICAL EVALUATION NAKNEK GEOTHERMAL SOURCES, ALASKA 1 .O INTRODUCTION This study presents the results of our preliminary geological evaluation of geothermal potential in the Naknek region of the Alaska Peninsula. The purpose of this preliminary study was to evaluate the previous studies and to indicate the feasibility of developing an active geothermal resource in this area. This report is based on the literature review conducted, Naknek Electric Association (NEA) field work, an HDL site visit, and geochemical analysis of fluids from one shallow well. This is a preliminary study to indicate the potential feasibility of developing an active geothermal resource for power generation. 2.0 BACKGROUND AND GEOTHERMAL RESOURCE CHARACTERIZATION 2.1 LOCATION Naknek is located on the Alaska Peninsula in the Bristol Bay Borough, Alaska. The area is located at Latitude at 58"44'23"N, Longitude 156O58'18"W. Naknek is located on the
north bank of the Naknek River, close to where the river runs into the Kvichak Bay arm
of the northeastern end of Bristol Bay. A vicinity map is presented in Figure 1 and
topographic and political site maps in Figures 2a and 2b. Naknek is accessible by air
and sea, and connects to King Salmon via a 15.5-mile road. The Tibbetts Airport in
Naknek has a lighted 1,700 foot long by 60 foot wide gravel runway. The State-owned
Naknek Airport is located one mile north of Naknek. It has a 1,950 foot long by 50 foot
wide lighted gravel runway and a 2,000 foot float plane landing area. Jet services are
available at King Salmon. The Borough operates the cargo dock at Naknek, which is a
port on Bristol Bay.
Traveling west to east across the Alaska Peninsula near Naknek, four distinct
physiographic regions are encountered: the coast, the Aleutian Range, the lake county,
and the Bristol Bay lowlands (U.S. National Park Service, 1994). Although the large
mountains and volcanoes contained in Katmai National Park are visible to the east,
Naknek is located on the Bristol Bay lowlands, an area of low relief and moist tundra.
Katmai National Park is approximately 10 miles from the King Salmon Airport.
NEA generates power to meet the demand of 3 megawatts (MW) in the winter with an
increase to 7.3 MW during the summer months due to the canneries and fish
September 2007 Page 1
Naknek Electric Association HDL 07-302 Preliminary Geological Evaluation Naknek Geothermal Sources, Alaska processing. The communities of Naknek and King Salmon have a population of 1120 according to the 2000 census. The regional power peak demand is approximately 8.4 MW in the winter and 13.1 MW in the summer, and includes the load from 23 local communities. The production of a regional geothermal facility has the potential to displace the use of 3.5 million gallons of diesel fuel annually. The cost of diesel ranges from $2.20 to $4.46 per gallon in the area. NEA envisions as many as 30 local communities could eventually benefit from a geothermal power project, starting with a 25-megawatt plant and expanding the capacity in 12.5 MW increments as additional communities are connected and demand increases. Financial feasibility of this project depends on the existence of an economically viable resource in the Naknek area. Figure 3 presents a geologic cross section of the Alaska Peninsula from south to north. Figure 4 is the key to the GIs project maps which follow. These maps start with the immediate vicinity of the NEA test hole and soil sampling sites in Figures 5a-d. Each map in the series shows various possible overlays of the different data sets available as a tool to visualize the synthesis of the geologic data. Figures 6a-d zoom out a bit to show the greater Naknek area, and Figures 7a-d zoom out further to show the Alaska Peninsula. 2.2 GEOTHERMAL SYSTEMS Geothermal systems can be divided into volcanic hosted systems, sedimentary basin systems, and isolated systems. If a geothermal system is near Naknek it would most likely be a volcanic hosted system. Volcanic hosted systems can be further broken down to island arc systems, typified by New Zealand systems; rift systems, typified by
East Africa and Iceland systems; basin and range systems such as Dixie Valley and
Beowawe in Nevada, and California-Sierran mixed with extensional and transverse fault
systems such as Coso and Imperial Valley. In each of these systems there is a heat
source either from current or recently solidified magma bodies. It is the flow of fluid in
hydrothermal convective systems that determine the temperature and fluid distribution in
the reservoirs. In addition to their geological setting, geothermal systems are classified
as either vapor-dominated or hot-water systems. Vapordominated systems have pure
high-temperature steam that is greater than 455°F. In liquid-water systems typical
temperatures range is 300°F to 570°F.
A variety of models have been developed over the years to explain specific systems,
with only a few attempting to apply general principles to a "typical" system. In 1983,
Henly and Ellis produced two generalized models of a typical liquiddominated
geothermal system in two types of volcanic environments: continental and island arc.
Figure 2.1 shows these two models. In the first model (a) chloride waters, created by
chemical interactions of water-rock-magma at depth, rise and boil, and the resultant
steam migrates to the surface. Near-surface condensation and oxidation of transported
H2S produces sulfate-dominated, steam-heated waters. Near-neutral pH chloride springs
September 2007 Page 2 gDL1w*zez
Naknek Electric Association Preliminary Geological Evaluation HDL 07-302 Naknek Geothermal Sources, Alaska occur on the surface. High relief andesite volcanoes, similar to Katmai, (b) create lateral flow of hot chloride water, and near-surface exsolving gases escaping from solution produce acid-sulfate-chloride lakes and large argillic alteration zones. This second type of system would be the expected type in the Naknek area. Figure 2.1 a) Typical geothermal system in silicic-volcanic environment. Temperature distribution is based on the system at Wairakei, New Zealand. b) Typical geothermal system in andesitic volcanics. Note the extensive lateral flow and large advanced-argillic alteration zone related to high-level volcanism. (Henley 1985).
Researchers now believe that geothermal systems are much more complicated than the
simple models produced two decades ago. However, the simple models presented form
the basis for exploring new systems.
2.3 GEOLOGY
Regional Tectonics
The Alaska Peninsula is a 500-mile long extension of the continental mainland of Alaska,
and the Aleutian Range forms its eastern backbone. Rising more than 7,000 feet above
sea level the Aleutian Range marks the convergent margin of the North American and
the Pacific Plates. Along the Aleutian Range, the Pacific Plate is moving generally
north-west at approximately 2.5 incheslyear with respect to, and subducting (diving)
underneath, the North American Plate. The off-shore Aleutian Trench marks the location
where the Pacific Plate begins its dive beneath the North American Plate (see Figure
2.3.1 for a general schematic of subduction zones.) The Aleutian subduction zone is a
segment of the circum-pacific Ring of Fire, one of the most active volcanic belts in the
world. Recent and ongoing volcanism in the Aleutians is the result of this subduction
September 2007 Page 3
Naknek Electric Association Preliminary Geological Evaluation HDL 07-302 Naknek Geothermal Sources, Alaska (Figure 2.3.1). Volcanism generally occurs directly above where the subducting slab reaches a depth of about 80 miles. The reasons for this are not fully understood, but are thought to be related to water released from and heating of the subducting plate. I' TY PlCAL SUBDUCTION ZONE COMPONENTS 1 yii I4 ~ Y. Volcano A. The model of a simple subducting slab is complicated by other factors. In the region of the Wrangells to the east, a block known as the Yakutat Terrane is colliding with continental Alaska, and has been for the past 5 to 10 million years. This is squeezing
crust westward along major faults such as the Denali and Castle mountain systems.
Faults mapped on the Alaska Peninsula, such as the Castle Mountain Fault and the
Bruin Bay fault, may help take up some of this lateral movement (see the faulting section
below).
Non-volcanic mountains in the Aleutian range of the Alaska Peninsula near Naknek are
comprised mainly of Jurassic rocks, presumably formed in a similar tectonic environment
in the distant past. Granites and metamorphics are remnants of the roots of these
ancient volcanoes, and sedimentary rocks, often with plant or sea-life fossils, represent
the material eroded from these volcanoes and mountains and deposited in lowlands and
near-shore oceans. These strata have since been upthrust by the ongoing convergence
of the plates to heights of 4000 feet or more. A north-south geologic cross-section of the
Alaska Peninsula has been inferred from oil well borings and seismic reflection data
(Figure 3). This shows that the Naknek region is likely underlain by Jurassic aged
(approximately 144 to 206 million years old) gMnlte and metamorphic rocks and covered
by roughly 2000 feet of glacial sedimentary formations (the Pleistocene Nushagak and
Pliocene Milky River Formations.) This cross-section infers a much shallower depth to
the granitic material in the near vicinity to Naknek than further south along the section.
September 2007 Page 4
Naknek Electric Association Preliminary Geological Evaluation HDL 07-302 Naknek Geothermal Sources, Alaska Granitic rocks generally have high radiogenic components and can generate crustal heat anomalies. It may be possible that temperature gradients beneath Naknek differ from the local oil wells. These local wells on the west side of the peninsula are all significantly south of Naknek, and the cross-section infers that the depth to granitic material is about 5,000 feet or more. Some regions of subduction, such as the Marianas subduction zone, exhibit back-arc spreading (Figure 2.3.2). This thins the overriding crust and leads to high heat flow. This process is unlikely to be occurring in the Alaska Peninsula region. Factors associated with back-arc spreading are old, thick, cold and dense rocks that dip steeply in subduction with a resulting deep trench and no great compressional earthquakes. Although the exact behavior of the Aleutian back-arc area is not well constrained, it is more likely to be in compression such as the Chilean system with a younger (and thus thinner, hotter, and more buoyant), shallowly dipping, subducting lithosphere and great compressional earthquakes (such as the 1960 Chilean Earthquake of magnitude 9.5 and the I964 Alaska Earthquake of magnitude 9.2.) ,bsohte Plate Moth !&tiw Plate Motians
Figure 2.3.2 Model of Mananas-style Back-arc spreading.
n
September 2007 Page 5 ="'ti . 1
Naknek Electric Association Preliminary Geological Evaluation HDL 07-302 Naknek Geothermal Sources, Alaska Local Faulting The occurrence and behavior of faults is important in geothermal exploration. Geothermal potential is related to open fractures and faults which may provide pathways for geotherrnally heated fluids to migrate in the crust, and the movement of faults in the presence of friction provides a mechanism for heat generation. The Bruin Bay Fault cuts through Katmai National Park to the east of Naknek and can be mapped for 330 miles from Mt. Susitna to the south shore of Becharof Lake (Figure 7b). Magnetic data suggests it may continue southwest toward Aniakchak caldera (Stevens et al, 2003, Detterman et al, 1987). This fault is described as a major thrust fault (upidown motion) dipping 45 to 80 degrees to the northwest, although Haeussler and Saltus also call it a strike-slip (IeWright motion) fault system. Significant evidence exists for both strike-slip and vertical thrust behavior on the nearby Lake ClarklCastle Mountain fault system. Given the dynamics of the region, including convergence of the Pacific and North American plates as well as the collision of the Yakutat block to the east, it makes sense for these faults to take up motion in both of these senses. Evidence for vertical motion on the Bruin Bay Fault includes early Jurassic granite and Tertiary volcanics upthrown on the northwest side into surface contact with relatively flat-lying later Jurassic Naknek sandstone on the southeast side (Ward and Matumoto, 1967). The detailed geology and associated structure are very complex. The Lake Clark Fault to the northwest has had around 16 miles of offset to the right in the past 34 to 39 million years (Haeussler and Saltus, 2004). See Figure 7b. There are suspicions of active strike slip faults running along the volcanic arc in the
Katmai area (Freymuller, personal communication). Mapped faults often stop at the
edge of where the mapping was done, but the faults likely continue. Unrecognized faults
and continuations of faults are likely to exist on the peninsula. These faults may be
hidden by sediments (such as the thick glacial sediments overlying the Naknek area,)
ocean, or vegetation; or they may just exist in relatively unexplored regions.
GPS data can show present crustal movement of plates, blocks or across faults. GPS
data collected by Freymueller and others from the University of Alaska at Fairbanks
show that the entire Alaska Peninsula is moving, which they have recently interpreted in
terms of a rigid Bering plate (Cross and Freymueller, 2007). The deformation observed
across the Peninsula is interpreted as mainly being due to elastic strain from the locked
subduction zone. The stations are relatively sparse on the peninsula, and do not resolve
motion across individual faults. In this area of complex tectonic processes, faulting and
fracturing on many scales is to be expected.
September 2007 Page 6 r#C",?S
Naknek Electric Association HDL 07-302 Preliminary Geological Evaluation Naknek Geothermal Sources. Alaska Volcanic Activity The majority of geothermal systems in the world are associated with volcanic centers. The closest volcanic centers to Naknek include the Katmai group of volcanoes about 70 miles to the southeast and Ukinrek Maars and Ugashik Peulik volcanoes about 70 miles to the south (refer to Figure 7b inset). Abundant evidence for the recent and present activity of the Katmai volcanoes comes from observations of volcanic eruptions since 1870 and ash stratigraphy (Ward and Matumoto, 1967). In 1912, Novarupta erupted violently, ejecting over 8 cubic miles of pyroclastic material, making it the most voluminous eruption of the twentieth century (Hildreth, 1987). For comparison, in historic times, only Greece's Santorini in 1500 B.C. ejected more volcanic matter than Novarupta. The 1883 eruption of Indonesia's Krakatoa ejected only a bit more than one half as much material. In addition to Novarupta, five other volcanoes in the vicinity of Novarupta have been intermittently active since 1912: Mount Katmai, Mount Martin, Mount Mageik, Trident Volcano and Mount Griggs. Six more volcanoes, which have had no activity recorded in the last 200 years, are considered active: Mount Dension, Mount Stellar, Kukak Volcano, Kaguyak Volcano, Four-Peaked Mountain, and Mount Douglas (U.S. National Park Service, 1994). See Figure 7b inset for a map of volcanoes in the area. Steam plumes occasionally rise from Mountains Mageik, Martin, and Trident. Mount Trident has erupted four times in recent decades, its last eruptive explosion taking place in 1968. The Ukinrek Maars are located on a low (less than 330 feet high), 2.5-mile-long, ridge in the Bering Sea Lowland 1 mile south of Becharof Lake and 7.5 miles northwest of Peulik Volcano. They represent one of the few examples of back-arc volcanism in Alaska
(Miller et al., 1998). The pair of explosion vents formed during a 10 day eruption of
basalts in 1977 where no volcano previously existed. The Maars are near the Gas
Rocks, which is an older volcanic area, and both the olivine basalts from the Maars
(Kienle et al., 1980). and the carbon dioxide that continuously issues from the nearby
Gas Rocks (Barnes and McCoy, 1979) appears derived from the mantle of the earth.
According to the Alaska Volcano Observatory web site, the Maars are the result of the
explosive interaction of surface or subsurface water and magma. West Maar is elliptical
in shape and up to 560 feet in diameter and 115 feet deep, on the northwest end of the
ridge (Kienle and others, 1980). East Maar, 2000 feet east of West Maar, is at a lower
elevation and is circular, approximately 1000 feet in diameter and 230 feet deep, and
has a 160-foot-high central lava dome that is now partly covered by a crater lake.
Location of the maars apparently coincides with, and may be controlled by, the
intersection of the Bruin Bay fault and regional structures (Kienle and others, 1980;
Detterman and others, 1983).
Mount Peulik is a small stratovolcano located just north of the main axis of the Aleutian
Range near Becharof Lake on the Alaska Peninsula (Figure 7b). The volcano lies west
of the axis of a northeast-striking syncline (fold) (Detterman and others, 1987) and is
September 2007 Page 7
Naknek Electric Association Preliminary Geological Evaluation HDL 07-302 Naknek Geothermal Sources, Alaska built upon Jurassic sedimentary rocks. The volcano partially overlaps the north flank of Ugashik caldera, a small circular structure about 3 miles in diameter and of probable late Pleistocene age. There are only two reports of historical activity at Mount Peulik, in 1814 and 1852. However, there is evidence of ongoing activity beneath the volcano. Remote sensing (inSAR) data showed inflation between October 1996 to September 1998 centered on the southwest flank of the volcano of about 7.8 inches. From this data, scientists deduced that a magma body about 4.1 miles beneath the volcano expanded by about 65 million cubic yards during 1996 to 1998. Fumaroles and Hot Springs The closest zones of known geothermal resource are associated with the volcanic centers in Katmai and at Ukinrek Maars and gas rocks. After the valley of 10,000 smokes in Katmai was blanketed with pumiceous fallout from the 1912 Novarupta eruption, fumaroles discharged from the ash-flow sheet and were vigorously active when discovered in 1916 (Griggs, 1922). Cooling of the ash-flow sheet and the influx of surface waters caused the fumaroles away from the volcanic vent to gradually cool and die out [Allen and Zies (1923), Fenner (1923), Zies (1924)l. In the vicinity of the vent, hydrothermally active areas as hot as 90°C (194°F) in 1986 have been mapped as discontinuous, elongate, clay-altered layers concentrated along some of the concentric fractures outlining the Novarupta caldera, as well as along systems of cross-fractures (Keith, 1986). The hottest thermal springs in the Katmai Cluster are measured at 167°C (333°F) on Mount Mageik according to the Geothermal Resources of Aleutian Arc. The most recent temperature measurement of the surface waters at Ukinrek Maars is
16°C (61°F). Gas Rocks is located a little over a mile north of the Maars. Even before
the eruption and formation of the Maars, large amounts of carbon dioxide gas were
discharged at this site. Following the formation of the Maars, the amount of this gas
increased significantly and briny thermal springs appeared. These have a measured
surface temperature of 39°C (102"F), with a reservoir temperature of 108°C (226°F)
listed in the Geothermal Resources of Aleutian Arc.
Aeromagnetic Anomalies
Aeromagnetic data on the Alaska Peninsula shows both positive and negative anomalies
in the near vicinity of Naknek (see Figures 5c, 6c and 7c). There are apparent northeast
to southwest linear trends in both the high and low magnetic anomaly areas, as well as a
more "blobby" structure. Glacial sediments tend to be non-magnetic. Magnetic
anomalies could represent underlying rocks with a more magnetic signature, such as
buried volcanic flows or intrusions or sedimentary rocks with magnetic components. In
the Lake Clark region (Haeussler & Saltus, 2004), volcanic intrusives (interior magma
bodies) dated to the Late Cretaceous though Paleocene (approximately 57 to 72 million
years ago) are not associated with strong magnetic highs, but Oligocene dated (34 to 39
September 2007 Page 8 =??'%
Naknek Electric Association HDL 07-302 Preliminary Geological Evaluation Naknek Geothermal Sources. Alaska million years ago) volcanic intrusives are associated with magnetic highs. The polarity of the earth's magnetic field has switched many times in the past, and thus a highly magnetized body could be a high or low anomaly depending upon the time of emplacement. Magnetic lows in the Lake Clark area have been interpreted to indicate fault traces. Smith et al (2002) show that high gradients in the magnetic anomalies (such as abrupt changes from high to low) often correspond to fault traces, and use the data to identify buried faults in Dixie Valley, Nevada. Gravity Anomalies Gravity anomalies have also been mapped on the Alaska Peninsula (Figures 5d, 6d, and 7d). The resolution is relatively low, but shows the Naknek area to be in a region of a moderately high Bouguer gravity anomaly. Gravity lows may be expected for fractured rock associated with faults or relatively low density material (rock or magma) at depth. The resolution of this data does not seem to be high enough to preclude the presence of local faulting with associated gravity lows, even though none are apparent. Remote Sensing A remote sensing study was undertaken by Lapp Resources, Inc. They used airborne digital multispectral video to visually search for evidence of natural linear trends in the region that could be significant geologic features such as faults. They also used the visual colored images to search for anomalous or unusual looking areas. These areas may represent altered sediments or stressed vegetation, and could be caused by hydrocarbon or geothermal "microseepage". Three larger areas of these anomalies are identified near the Naknek River in the vicinity of King Salmon. These areas also seem
to nearly correspond with the location of the crossing area of two linear aeromagnetic
lows (see Figures 4, 5a-d, and 6a-d for a key and the mapped features.)
Regional Temperature Gradients
Temperature gradients from regional oil and gas wells are shown below in Table 2.3.
The wells are listed in order of distance from Naknek, although other factors such as
distance from volcanic centers, will also impact their correlation with expected gradients
at Naknek. Temperature gradient is either listed as reported in other sources or
calculated. Sources include Magwn et al., 1995 except for Becharof 1 which the
temperature gradient if from a plot of drill stem test temperatures. Temperature gradient
was calculated as (Temperature - 40°F)/depth (assumes a surface temperature of 40°F).
Well locations are shown in Figures 7a-dl the lniskin wells are off the maps to the
northeast. Wells in the vicinity shown on Figures 7a-d that are not listed here have no
thermal data available. Temperatures are bottom hole temperatures except where
noted. It should be noted that all of these wells are closer to the volcanoes of the
Aleutians than is Naknek. The highest gradient is seen in the Big River well, and this
well is in an area of volcanic activity.
September 2007 Page 9
Naknek Electric Association HDL 07-302 Preliminary Geological Evaluation Naknek Geothermal Sources. Alaska Gas Wells Table 2.3 Temperature Gradients from Oil and Temp. Gradient Well Name Date Approx. Distance to Naknek Depth(ft) I I Great Basins 1 1 11,080 I 183°F Temp. 60 miles 70 miles Becharof I Bear Creek unit 1 Wide Bay I Ugashik 1 Painter Creek KoniagChevron 1 90 miles 95 miles 95 miles 110 miles 9,023 12,063 12,568 9,476 7,912 10,905 Big River 11,371 398°F COST I 17,155 316°F Hoodoo 1 Hoodoo 2 11,243 194°F David River 13,769 285°F 21 0°F 227°F 283"F* 198°F 150°F 126"F* 0.79"F/IOO ft 0.69"F/100 ft 1.75-1 -91 "F/IOOft 1.62"FM 00 ft 1.47"F/100 ft 1.86"F/100 ft 3.21 -3.61 OF11 00ft 1.7"F/100 ft 1.65"F/100 ft 1 -73-2.27"F/IOOft 2.07"F/100 ft 1981 1985 1972 1955 1959 1963 1977 1983 1970 1970 1969 Canoe Bay Cathedral River
* indicates maximum measured temperature
120miles 130 miles 140 miles 150 miles 150miles 200 miles 220 miles 250 miles 250 miles 250 miles 250miles 2.2g°F/1 00 ft 1.65-1.94"F/100ft
nstead of bottom hole temperature.
6,642 14,301
2.4 HYDROGEOLOGY
160°F 278°F 1961 1974
Physiography
The Aleutian Range separates the Katmai coastal region from the lake country, which is
comprised of low, rolling hills, white spruce forest and large deep lakes, such as Naknek,
Coville and Grosvenor. Lake basins were carved out by glaciers originating in the
Aleutian Range during several advances between 8,000 and 25,000 years ago. The
deepest recorded lake depth is 530 feet in the lliuk Arm of Naknek Lake. Lakes become
much shallower toward the west as a result of glacial deposition (U.S. National Park
Service, 1994). Lake basins are made of various rocks, as igneous intrusions are
juxtaposed with sedimentary formations (Gunther, 1992). Rivers drain from the highland
areas to these lakes and eventually flow into the Naknek River in the moist tundra of the
Bristol Bay lowlands. This tundra is similar to that found in arctic Alaska due to the
maritime climatic influences at this lower latitude. Bedrock here is covered by thick
deposits of quaternary glacial sediments. The Naknek River runs into Kvichak Bay very
270 miles 280 miles
September 2007 Page 10 Kr""-
Naknek Electric Association Preliminary Geological Evaluation HDL 07-302 Naknek Geothermal Sources, Alaska near the town of Naknek. The Naknek River drainage area is approximately 3,700 square miles and includes seven interconnecting lakes. The Naknek River is tidally influenced as far up as King Salmon (NCDC, 1988). Groundwater Hydrology The King Salmon area has at least 3 known aquifers, designated A, B, and C (Paug-Vik Development Corp et al., 2000). These consist of unconsolidated silty and gravelly sands separated by aquitard units of silty sands, silts and clays. Aquifer A is the shallowest. It is unconfined and exposed in places, ranging from the surface at the Naknek River to 45 feet below ground surface (bgs). The saturated thickness ranges from 0 to 15 feet. Groundwater movement is toward drainages and topographic lows such as wetlands and creeks and it is believed to be recharged by precipitation and stream flow. The depth to the top of Aquifer B ranges from 50 to 80 feet bgs, and its total thickness is from 15 to 40 feet. It is likely in hydrostatic equilibrium with Aquifer A. Aquifer C lays at a depth of about 200 feet bgs. It is probably confined, but its thickness and direction of groundwater movement are unknown. Glaciers, Lake Ice, and Snowpack The region has a history of multiple glaciations which at their maximum, extended nearly 100 miles west of the Aleutian Range across Kvichak Bay (Muller and Ward, 1966). The hydrologic cycle in the Naknek region is influenced in part by extensive glaciers and snowfields that supply large quantities of silty melt water to the headwaters of drainage
basins during the summer months. Mean annual frozen precipitation totals for King
Salmon is 46.1 inches. In comparison, the Katmai coast on the other side of the
Aleutian range experiences frozen precipitation totals approaching those of Kodiak at
77.4 inches (National Oceanic and Atmospheric Administration, 1998). Seasonal ice and
snow cover affects the characteristics of aquatic ecosystems. It controls the amount of
light reaching the unfrozen water beneath the ice (Prowse and Stephenson, 1986). Ice
can also prevent gas exchange between underlying waters and the atmosphere and
may commonly lead to depletion of dissolved oxygen and the build up of reduced gasses
such as C02, CH4 and H2S (Rouse et al., 1997). The region is also underlain by
discontinuous or isolated masses of permafrost, which can greatly influence the
hydrologic cycle (Dearbom, 1979). For example, permafrost can prevent precipitation
from recharging aquifer systems, thus surface runoff provides a greater contribution to
lake and stream recharge.
[-
September 2007 Page 11 ~w-T?:d.d
Naknek Electric Association HDL 07-302 Preliminary Geological Evaluation Naknek Geothermal Sources. Alaska 3.0 NAKNEK ELECTRIC ASSOCIATION STUDIES Naknek Electric Association (NEA) conducted a number of studies prior to June 2007. These have included soil sampling at several locations throughout the Naknek area and advancing three borings to between 255 to 400 feet. Figures 5a-d show the locations of the soil sampling and borings. The three borings were advanced using an airlwater rotary drilling rig provided by Denali Drilling of Anchorage, Alaska. Borehole 1 was located on the southside of Naknek River and was advanced to 395 feet. Borehole 2 was located at Herman's Pit and was advanced to 255 feet. Borehole 3 was located on Pikes Ridge and was advanced to 400 feet. Bedrock was encountered in the bottom of Borehole 2 and approximately 10 feet of core was obtained. Jim Clough of the Alaska Division of Geological & Geophysical Surveys identified the rock sample as Meshik formation volcanics of Oligocene age (Appendix A). It was further identified as a pyroclastic or spatter deposit. Water samples were collected from Borehole 2 as well. 3.1 Soil Sampling Mercury and Arsenic Elevated levels of mercury (Hg) and arsenic (As) in soils are often used as tracers for geothermal activity. Mercury is easily volatized and mobilized by heat and transported upwards from any geothermal source, thus it can indicate high vertical permeability and hydrothermal circulation. Arsenic is mobilized by geothermal fluids. Soils concentrations of either element, however, can be affected by other factors. In the case of mercury, the presence of organics, clays, or iron and manganese oxides are all known to elevate measured levels of mercury, and pH can also be a factor.
Measured levels of mercury depend on the method used and background levels can be
very different in different areas. Usually, researchers search for locally anomalous
values to indicate zones of higher vertical permeability and geothermal fluids at depth.
In Naknek, samples were collected on 911012006 approximately every 2 miles along
three lines that paralleled the Naknek River. Samples were taken from 2 to 3 feet in
depth and organic matter was avoided where possible. Sample A7B had lots of
organics; sample A4B had roots sieved out of it; ASA and A5B are noted as 'muddy' and
may have some organics; and samples C3A and C3B had a sulfur smell, which likely
indicates the presence of anaerobic organic material, but this smell can also be
associated with geothermal activity. Samples AIA-T2 and B8B were clayey, which can
lead to elevated levels of mercury, but in this case does not seem to be associated with
relatively high levels of mercury or arsenic. The highest concentrations of As and Hg
were found in sample C3, as can be seen in Figures 3.1.1 and 3.1.2 below. See map
(Figures 5a-d) and Appendix B for sampling locations and notes.
September 2007 Page 12
Naknek Electric Association Preliminary Geological Evaluation HDL 07-302 Naknek Geothermal Sources, Alaska I i , Arsenic in Soil Samples I - - - - - .- -- - -. Figure 3.1.1 Arsenic levels in NEA soil samples - see map in Figure 5a for locations 8' Sample #
September 2007 Page 13
Naknek Electric Association Preliminary Geological Evahtath HDL 07-302 Naknek Geothermal Sources, Alaska Mercury in Soil Samples 4 5 Sample #
Figure 3.1.2 Mercury levels in NEA soil samples. See map in Figure Sa for locations.
Soil samples tested from the Zimin Allotment (Pikes Ridge, See Figure 5a for locations)
are plotted below in Figure 3.1.3 and 3.1.4. It can be seen that arsenic values are
slightly higher to the east of the allotment, and higher mercury values to the north.
These sampes are plotted separately from the other soil sampling results to show the
high variability possible in a small area.
September 2007 Page 14
Naknek Electric Association HDL 07-302 Preliminary Geological Evaluation Naknek Geothermal Sources. Alaska . - --- - - - Zimin Allotment: Arsenic Figure 3.1.3 Samples \ . - - - - . . -- - Zimin Allotment: Mercury west Figure 3.1.4 e also taken from the three drill holes advanced in the spring 2007 for this projed (see Figure 5a for a map) and were analyzed for metals including arsenic using method ME-ICP41. The arsenic values vs. depth in each drill hole can be seen in Figure 3.1.5 below. - - - - - - - - - - - - - - - - - I I Arsenic in Drill Holes I
0-30 30-6060-90 90- 120- 150- 180- 210- 240- 270- 300- 330- 360-
120 150 180 210 240 270 300 330 360 400
Depth in Hole (R)
...
Figure 3.1.5
Areas that rarely or never freeze were also sampled (both water and soil) in the fall of
2006 were also tested for mercury and arsenic levels. In no case was mercury detected
above the limit of 0.135 mg/kg in dry sample in the soils or 0.0002 mg/L in the water.
Arsenic levels are depicted in Figure 3.1.6 below for each sample. The water samples
had little or no detectable arsenic.
September 2007 Page 15 mm!
Naknek Electric Association HDL 07-302 Preliminary Geological Evaluation Naknek Geothermal Sources. Alaska Unfrozen Areas: Arsenic I Sample name Figure 3.1.6 In all cases of testing, the arsenic and mercury levels were moderate, and high values were usually within two standard deviations of the mean of the samples' values. Only in soil sample C3A and in one sample from Drill Hole 2 (Hermann's Pit) were the arsenic levels above two standard deviations. Only in soil sample C2A and C3A were mercury levels above two standard deviations.
3.2 GEOCHEMISTRY
Deuterium and Oxygen-1 8
Three samples of water were collected during the drilling of Borehole 2 (Hermann's Pit).
The samples were of local river water, water collected during the drilling of Borehole 2
and water collected from the bottom of Borehole 2. These were analyzed by the UAF
Alaska Stable Isotope Facility for deuterium and oxygen-I 8. Deuterium and oxygen-1 8
(or 180) are heavy, stable forms of the elements hydrogen and oxygen, respectively. 6 D
is the ratio of deuterium to normal hydrogen relative to a standard known as SMOW
(standard mean ocean water) in parts per thousand. 6 180 is the ratio of oxygen-1 8 to
oxygen-16 relative to SMOW in parts per thousand. Meteoric waters (those waters
derived from precipitation) fall on a line defined by 6 D = 8 6 180 + 10, as seen in Figure
3.2 below. Magmatic waters plot significantly off this line. Thermal alteration of meteoric
waters in contact with rocks can increase the value of 6 180, but since rocks contain very
little hydrogen, they do not significantly alter the value of 6 D. This can be seen in
Figure 3.2. When the three Naknek samples are plotted, they fall on or very near the
meteoric water line. The sample from the bottom of the boring falls slightly to the right of
September 2007 Page 16 mp#$?%
Naknek Electric Association HDL 07-302 Preliminary Geological Evaluation Naknek Geothermal Sources. Alaska this line, perhaps indicating a small amount of interaction with the surrounding ground, but not enough to show significant thermal alteration. ALTERED METEORIC THERMAL WATERS /2S,a \Losoan Peak /Steamboat Springs Is' 8 '*o (%o) Figure 3.2 Oxygen-18 and Deuterium compositions of hot spring, fumerole, and drill hole thermal fluids derived from meteoric waters (black open symbols) and of meteoric waters local to each system (black dosed symbols). From Truesdell and Hulston (1980). Geothermometry The three samples of water collected during the drilling of Borehole 2 (Herrnann's Pit) were also analyzed chemically by the laboratory at New Mexico Tech for
geothermometry. Geothermometry is the process of using the chemistry of a fluid to
indicate what its deeper reservoir temperature may be. In the case of silica
geothermometry, the concentration of silica in the water is used to calculate the highest
temperature the water may have been subjected to in its past. Generally, the solubility
of silica is temperature dependent; the hotter the fluid, the more silica gets dissolved in it
from surrounding rocks. As a fluid cools conductively, the temperature loss is slow and
the loss of dissolved silica in the water is also slow enough to generally be considered
negligible. If fluid is lost as steam due to boiling, or if mixing with cold water has
occurred, this result will need a correction for these factors. If the boiling and mixing
history of the water is unknown, such as in our case, the derived temperatures will need
to be used cautiously. Note that this geothermometry does not give an indication of how
deep or where this temperature may be found.
.J yw --. ,
The three samples taken were of local river water, water collected during the drilling of
Borehole 2 and water collected from the bottom of Borehole 2. The result of the silica
geothermometery for the well bottom water is 88°C (190°F). Relative concentrations of
sodium, potassium and magnesium can also be used to derive a temperature. The
analysis plots on Giggenbach's (1986) Na-K-Mg-T diagram at about 90°C (194°F). The
September 2007 Page 17 luJ%
Naknek Electric Association Preliminary Geological Evaluation HDL 07-302 Naknek Geothermal Sources, Alaska bottom well water is chemically different from the other two samples, especially in pH (6.4 in the hole bottom and 7.8 to 7.9 in the other waters) and total dissolved solids, which are much higher in the bottom well water. Chemically, the drill-hole water is a sodium-bicarbonate or sodium-sulfate water. Sodium and sulfate are both typical of geothermal waters, bicarbonate is more typical of cold groundwaters. In the river water, calcium is the predominant cation, as is expected from cold groundwaters. 4.0 GEOTHERMAL POTENTIAL The geologic information admits various possibilities for geothermal potential in the Naknek region. The existence of the large and recent volcanic activity in the nearby Katmai region shows the geothermal potential of the convergent margin. Naknek is over 60 miles from these volcanoes, so it is unlikely to be directly affected by any magma bodies directly under the volcanoes. However, the regional temperature gradient in the whole Alaska Peninsula away from volcanic centers seems to be in the range of 2°F or slightly less per 100 feet. This is corroborated by bottom hole temperatures from wells drilled in the area for oil exploration (see Table 2.3 above). To utilize the regional temperature gradient of 2°F per 100 feet to produce geothermal power in Naknek, a well of 10,700 feet deep would be needed, given that the starting ground temperature at the surface is around 36°F. Traditional geothermal power plants have needed fluids in excess of around 250°F to operate in a commercially viable way. At this temperature, each well is likely to produce
1.5 MW of power or less. This is sustainable only if the fluids can be recharged in the
aquifer tapped by the wells. The energy available at the well heads is based upon the
flow rate and the temperature of the fluid. In order to produce 1.5 MW of power from
250 OF fluid, a well would need a flow rate on the order of 2,000 gallons per minute or
more. The geothermometry from the fluids found in the bottom of the shallow well at the
gravel pit site indicate that they may have been at temperatures of 194°F (see section
3.2 above), at an undetermined depth. Lower temperature fluids of around 165°F have
been utilized at Chena, but the power production per well is much smaller. Chena's
power outputs are on the order of 200 kW. This is based on a known shallow source.
According to NEA, the regional peak power usage is around 13 MW in the summer.
Assuming that the temperature gradient is 2°F per 100 feet, reaching 250 OF fluid would
necessitate drilling to a depth of about 11,000 feet. Nine such successful wells,
producing about 1.5 MW a piece, would be necessary to meet the regional power needs.
Drilling costs from the oil industry for wells this deep is about 4 M$ each.
Natural enhancements to this background geothermal gradient would increase the
geothermal viability of the area. These enhancements could be due to such things as,
September 2007 Page 18 ~NXW em, .-at
Naknek Electric Association Preliminary Geological Evaluation HDL 07-302 Naknek Geothermal Sources, Alaska faults that allow deeper, hotter, fluids to rise towards the surface or laterally from a source near the volcanic centers; high radiogenic heat in subsurface granites (radiogenic heat is that caused by the decay of radioactive elements found naturally in granite); or perhaps (but less likely) older but still warm magma bodies at depth. These mechanisms for providing hotter temperatures nearer the surface are all speculative in this area, but possible thermally anomalous areas have been identified in the region of Naknek by remote sensing (Lapp Resources, Inc, 2006). More work needs to be done to measure the heat flow in these areas, define their geochemistry, and attempt to find associated features such as faults through geophysical methods. The Landsat imagery shows the landforms in the area, including the volcanoes, bodies of water and glacial moraines (see Figures §a, 6a, and 7a). The geologic maps of the area point out the locations of known faults and show the geologic formations on the peninsula (see Figures 5b, 6b, and 7b). The known geologic faults are almost entirely in the region of better exposed bedrock to the east of the Bruin Bay Fault. The maps show that to the west the land is mostly covered with recent glacial material, and thus any faults in this area would be buried. The magnetic anomalies may indicate, among other things, the location of faults in the area (see Figures 5c, 6c, and 7c). Particularly intriguing are the linear magnetic anomaly features in the vicinity of the NEA drilling sites and the three large (possibly thermal) anomalies noted by Lapp Resources, Inc. in their remote sensing study (see Figure 5c). A northeast to southwest-trending linear magnetic low appears to cross one trending northwest to southeast in this region. These lows could indicate the presence of crossing faults in this area, and this area would be a
good place to conduct more research as outlined below in the conclusions. The
Bouguer gravity anomaly may indicate the subsurface geology (see Figures 5d, 6d, and
7d). The NEA test holes reveal clues about the shallow subsurface, and the soil testing
sites may give an indication of relative geothermal potential, where high values of
arsenic and or mercury can result from geothermal action. All of NEA's soil testing sites
in the CA and CB sampling areas lie within or near the area of interest for further
research (see Figures 5a-d).
The shallow test well drilled by NEA this year at the gravel pit site (see Figure 5a) is a
good location to start from as the presence of shallow bedrock and fluids at depth has
been confirmed there, as well as geothermometry indicating the possibility of warm
source fluids.
5.0 CONCLUSIONS
At this time (September, 2007) a resource has not been confirmed. An exploration
followed by a confirmation phase needs to be conducted prior to any decisions about
type of power plant and number of wells. We would recommend that two or more of the
September 2007 Page 19
Naknek Electric Association HDL 07-302 Preliminary Geological Evaluation Naknek Geothermal Sources. Alaska following exploration methods be conducted for assessing the local thermal and hydrological gradient: 1. Accurately and uniformly characterize the chemistry of local springs and river waters; 2. Conduct shallow temperature probes in select areas to develop a refined picture of the local geothermal gradient; 3. Conduct seismic andlor gravity studies to identify local faults and bedrock structures; 4. Conduct COz gas surveys to identify potential faults in select areas; 5. Conduct electric andlor magnetotelluric methods to identify argillic alteration locations and to target potential well locations; 6. Develop a hydrological model of the region by reviewing existing literature and studying deeper wells in the area; and 7. Consider potential locations closer to the volcanoes in the region. 6.0 LIMITATIONS The discussions in this report are based on literature review and on the studies conducted by Naknek Electric Association without direction from Hattenburg Dilley & Linnell. We have provided in this report our preliminary evaluation as to the potential of the area based on the data reviewed. The preliminary evaluation may change as new data is obtained.
Prepared By: Reviewed By:
Hattenburg Dilley & Linnell
@& Michelle Wilber
Hattenburg Dilley & Linnell
Lorie M. Dilley, P~CPG %-
Staff Geologist Principal Geologist
September 2007 Page 20 ).Dc%*
Naknek Electric Association Preliminary Geological Evaluation HDL 07-302 Naknek Geothermal Sources, Alaska Allen, E.T. and Zies. E.G. (1 923) A Chemical Study of the Fumaroles of the Katmai Region. National Geographic Society, Contrib. Tech. Pap., Katmai Series, 275155. Barnes, Ivan and George A. McCoy (1979) Possible role of mantle-derived C02 in causing two "phreatic" explosions in Alaska, Geology v. 7 Cross, R., and J. T. Freymueller (2007) Plate Coupling Variation and Block Translation in the Andreanof Segment of the Aleutian Arc Determined by Subduction Zone Modeling Using GPS data, Geophys. Res. Lett., 2006GL029073. Cross, R., and J. T. Freymueller, Evidence for and Implications of a Bering Plate Based on Geodetic Measurements from the Aleutians and Western Alaska, submitted to J. Geophys. Res., April 2007. Dearbom , L.L. (1979) Potential and Developed Water-Supply Sources in Alaska . [In] , Jour. of the Alaska Geol. Soc. 1981. Anchorage , AK .I :1-11. Detterman, R. L., Case, J. E., Wilson, F. H., Yount, M. E., and Allaway, W. H. Jr. (1983) Generalized geologic map of the Ugashik, Bristol Bay, and part of the Karluk quadrangles, Alaska: US. Geological Survey Miscellaneous Field Studies Map MF 1 539-A, unpaged, 1 sheet, scale 1 :250,000. Detterman, R.L., Case, J.E., Wilson, F.H., and Yount, M.E. (1 987) Geologic map of the Ugashik, Bristol Bay, and western pad of Karluk Quadrangle, Alaska: U.S.
Geological Survey Miscellaneous Investigations Series Map 1-1685, 1:250,000.
Fenner, C. N. (1 923) The origin and mode of emplacement of the great tuff deposit of
the Valley of Ten Thousand Smokes: National Geographic Society Contributed
Technical Papers, Katmai Series 0001,74 p.
Giggenbach, W. F. (1986) Graphical techniques for the evaluation of water/rock
equilibration conditions by use of Na, K, Mg, and Ca-contents of discharge waters:
Proceedings of the 8th New Zealand Geothermal Workshop, University of Auckland
Geothermal Institute, p. 37-43.
Griggs, R.F. (1 91 7) The Valley of Ten Thousand Smokes . The National Geographic
Magazine. National Geographic Society, Washington D.C. 31 (1 ):13-68.
Griggs, R. F. (1922) The Valley of Ten Thousand Smokes: Washington, DC, National
Geographic Society, 340 p
Gunther, A.J. (1 992) A Chemical Sunley of Remote Lakes of the Alagnak and Naknek
River Systems, Southwest Alaska. U .S.A. Arctic and Alpine Research 24(1):6468.
September 2007 Page 21
I , Naknek Electric Association HDL 07-302 Preliminary Geological Evaluation Naknek Geothermal Sources. Alaska Haeussler, Peter J. and Richard W. Saltus (2004) 26 km of Offset on the Lake Clark Fault Since Late Eocene Time, US. Geological Survey Professional Paper 1709-A. Hanse, Cedric Nathanael. (2005) Factors Atlkcting Costs of Geothermal Power Development. Geothermal Energy Association. Henley, R.W., A.H. Truesdell & P.B. Barton, Jr. (1 984) Fluid-Mineral Equilibria in Hydrothermal Systems, Reviews in Economic Geology, V. 1, Society of Economic Geologists. Hildreth, W. (1987) New Perspectives on the Eruption of 1912 in the Valley of Ten Thousand Smokes, Katmai National Park, Alaska . Bull. of Volcanology 49:680693. Keith, T.E.C. (1991) Fossil and Active Fumeroles in the 1912 Eruptive Deposits, Valley, of Ten Thousand Smokes, Alaska . Jour. Volcanol. Geotherm. Res., 45:227-244. Kienle, J. and S.E. Swanson (1 983) Volcanism in the Eastern Aleutian Arc: Late Quaternary and Holocene Centers , Tectonic Setting and Petrology. [In] B.H. Baker and A.R. McBirney (eds.), Jour. of Volcanology and Geothermal Research 17:393- 432. Kienle, Juergen, Kyle, P. R., Self, Stephen, Motyka, R. J., and Lorenz, Volker (1980) Ukinrek Maars, Alaska: I, April 1977 eruption sequence, petrology and tectonic setting: Journal of Volcanology and Geothermal Research, v. 7, n. 1, p. 11-37. Lapp Resources, Inc (2006) Remote Sensing Interp~tation, for Naknek Electric Association. Magoon, L.B., C.M. Molenaar, T.R. Bruns, M.A. Fisher, and Z.C. Valin (1 995) 1995
National assessment of United States oil and gas resources - Southern Alaska
Province (OOS), USGS
Miller, T. P., McGimsey, R. G., Richter, D. H., Riehle, J. R., Nye, C. J., Yount, M. E., and
Dumoulin, J. A. (1 998) Catalog of the historically active volcanoes of Alaska: U .S.
Geological Survey Open-File Report OF 98-0582, 104 p.
Motyka, R. J., Liss, S. A., Nye, C. J., and Moorman, M. A. (1993) Geothermal resources
of the Aleutian Arc: Alaska Division of Geological & Geophysical Surveys
Professional Report PR 01 14, 17 p., 4 sheets, scale 1:1,000,000.
Muller, E.H. and P. Ward (1 966) Savonoski Crater, Katmai National Monument, Alaska ,
1964. NSF Grant No. GP-2821. Dept. of Geology, Syracuse University & Lamont
Geological Observatory, Columbia University . 39 pp.
National Climatic Data Center (NCDC), (1988) Climatic Atlas of the Outer Continental
Shelf Waters and Coastal Regions of Alaska. Volume 11: Bering Sea. USDOl Mineral
Management Service, Alaska Outer Continental Region, OCS Study, MMS 87-0012.
September 2007 Page 22 my-,
Naknek Electric Association Preliminary Geological Evaluation HDL 07-302 Naknek Geothermal Sources, Alaska Paug-Vik Development Corp. and OASIS Environmental, Inc. (2000) Record of Decision for Final Remedial Action, North Bluff (L FOO5) and South Bluff (LF07 4) (Groundwater Zone 3 (OT029)), King Salmon Air Station, Department of the Air Force. Prowse, T.D. and R.L. Stephenson, R.L. (1 986) The Relationship Between Winter Lake Cover, Radiation receipts and the Oxygen Deficit in Temperate Lakes . Atmos-Ocean 24:386-403. Rafferty, Kevin (2000) Geothermal Power Generation, a primer on Low-Temperature, Small-Scale Applications: Fact Sheet by Department of Energy Geo-Heat Center. Smith. R.P., V. J. S. Grauch, and D.D. Blackwell (2002) Preliminary Results of a High- Resolution Aeromagnetic Survey To Identify Buried Faults at Dixie Valley, Nevada, Geothermal Resources Council Transactions, Vol26 Stevens, De Anne S.P. and Patty Craw (2003) Geologic Hazards in and Near the Northern Portion of the Bristol Bay Basin, State of Alaska Dept. of Natural Resources. Truesdell, A.H., and Hulston, J. R. (1980) Isotopic Evidence of Environments of Geothermal Systems; in Handbook of Environmental Isotope Geochemistry, v. 1 : P. Fritz and J. Ch. Fontes, eds. U.S. National Park Service (1 994) Resource Management Plan, Katmai National Park :, and Preserve. 324 pp. Ward, P.L. and T. Matumoto (1 967) A summary of volcanic and seismic activity in Katmai National Monument, Alaska; Bulletin of Volcanology, v. 31, no. 1
Wilson, F.H., Detterman, R.L., and DuBois, G.D., 1999, Digital data for geologic
framework of the Alaska Peninsula, southwest Alaska, and the Alaska Peninsula
terrane: U.S. Geological Survey Open-File Report OFR 99-31 7.
Zies, E. G. (1 924) The fumarolic incrustations in the Valley of Ten Thousand Smokes:
National Geographic Society Contributed Technical Papers, Katmai Series 0003, p.
157-1 79.
September 2007 Page 23
Arctic - Barn
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VlCNTY MAP
Alaska Peninsula Geologic Cross Section ide of Alaska Penisu la - Schematic Structure Sections Northwestern S Geologic Units NGURE 3 -81 1-81
Volca
I
noes of the Alaska Peninsula (from: AVO)
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Geologic Units [ Qa Alluvial deposits KJcv Chert and volcanic sequence 'Tv Volcanic rocks I ) Qaf Alluvial fan and landslide deposits - '(he Herendeen Formation 1 Tm Meshik Volcanics 1 Qb Marine beach and estuarine deposits (st Staniukovich Formation 1 TN Volcanic rocks ] Qmt Marine terrace deposits In Naknek Formation 1 Pv Volcanic rocks Qm Moraines and other glacial deposits - Jni Indecision Creek Sandstone Member Qi Intrusive rocks Tmr Milky River Formation Tbl Bear Lake Formation 1 Tta Tachilni Formation 1 Tu Unga Formation 1 Tbe Balkofski Formation I Th Hemlock Conglomerate , Ts Stepovak Formation Tt Tdstoi Formation Tc Copper Lake Formation ( Kh Hoodoo Formation Kc Chignik Formation I Kk Kaguyak Formation Ks Shumagin Formation Ksm Mudstone I Kp Pedmar Formation +Unfrozen Zones aNEA Drill Sites Soil Sampling Sites-As Js Shelikof Formation Jk Kialagvik Formation Jt Talkeetna Formation Trk Kamishak Formation PIS Limestone D Qv Volcanic rocks Qpd Pyrodastic and debris flow deposits / QTv Vdcanic rocks n QTp Pyroclastic flow deposits Jnk Katolinat Conglomerate Member a Ti Intrusive rocks Jns Snug Harbor Siltstone Member Tiu Intrusive rocks, undivided I Jnn Northeast Creek Sandstone Member I Tgd Granodiorite. Mt, Katmai region Jnc Ch~sik Conglomerate Member " I Tqd Quark diorite, Mt. Katmai region 1 Tg Granodiorite, Shumagin. Semidi, and Sanak Island! I Jgd Granodiorite 1 Jgr Granite Jqd Tonalite and quark diorite Jgb Diorite and gabbro QTc Contact-metamorphic rocks 1 JPk Kakhanok Complex ,J 'Trc Cottonwood Bay Greenstone 1 - - ] g Glaciers ] Water QTm Molzhovoi Volcanics Tvu Volcanic rocks, undivided ( Symbol size proportional to value
Soil Sampling Sites-Hg
( Symbol size proportional to value
Remote Sensing Features (LAPP, inc)
-Anomaly
-Circular
-Linear
AOil and Gas Wells
Faults - Normal
ApproximatelyLocated
Inferred Location
Thrust
Concealed
Bouguer Gravity Anomaly Magnetic Anomaly ..............................
Low Iw(aWI) High Low IT 1-..I High
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SCALE:
APPENDIX A Jim Clough's Report on Naknek Core
Naknek Core r-\ i.. ! The rocks encountered in the Naknek core (Photol) appear to be fiom the Eocene to Oligocene age (approx. 48 to 28 million year old) Meshik Volcanics that intertongue with the Stepovak Formation along much of the southwest side of the peninsula (Finzel and others, 2005). The Meshik Volcanics consist of andesitic to basaltic lava, breccia, tuff, and lahars, as much as 1500 m Paleogene sequence on the Alaska Peninsula thick (Detterman, 1985). The Meshik Volcanics (earlier name is Meshik Formation, Burk, 1965) are part of the Meshik arc system that was oriented along the trend of the Alaska Peninsula, subparallel to the present-day Aleutian arc (Wilson, 1985). Wilson (1985, p. 1) states: "Rocks of the Meshik arc are emplaced on Cenozoic, Mesozoic, and older clastic sedimentary rocks of the Alaska Peninsula terrane. Tectonic interpretation suggests: a) the arc represents a relatively stationary period in the otherwise mobile migration of the Alaska Peninsula terrane, b) subduction was an important process along the Alaska Peninsula during Tertiary time, and c) most migration of the Alaska Peninsula terrane since Cretaceous time took place in Paleocene and middle Miocene time." The three pieces of core (bottom, middle and top) were each cut in half by rock saw and photographed (Photos 2. Bottom Core, 3. Middle Core, and 4. Top Core). One half is being sent for thin-sections and the other half is being returned to NEA. Based on visual inspection, these rocks appear to be what is known as "spatter deposits" that result from volcanic vent eruptive activity. The following description of spatter deposits is from http://vulcan.wr.us~s.g0v/Glossary/T~hrddescrivtion tevhra.htm1 "If the scoria or pumice clots are sufficiently soft to flatten or splash as they strike the ground, they are called spatter. The still-molten character of spatter fragments can cause them to stick together to form welded spatter or agglutinate." (From: Tilling, Heliker, and Wright, 1987, Eruptions of Hawaiian Volcanoes: Past, Present, and Future: USGS Special Interest Publication.) References
Burk, C.A., 1965, Geology of the Alaska Peninsula -island arc and continental margin: Geological
Society of America Memoir 99,250 p., scales 1 :250,000 and 1 :500,000,2 sheets.
Detterman, R.L., 1985, Paleogene sequence on the Alaska Peninsula (Abst), AAPG-SEPM-SEG Pacific
section meeting; 22 May 1985; Anchorage, AK , American Association of Petroleum Geologists
Bulletin , Vol. 69, no. 4, P. 661
Finzel, E.S., Reifenstuhl, R.R., Decker, P.L., and Ridgway, K.D., 2005, Sedimentology, stratigraphy, and
hydrocarbon reservoir-source rock potential, using surface and subsurface data, of Tertiary and
Mesozoic strata, Bristol Bay Basin and Alaska Peninsula: Alaska Division of Geological &
Geophysical Surveys Preliminay Interpretive Report 2005-4,69 p.
Wilson, F.H., 1985, The Meshik Arc - an eocene to earliest miocene magmatic arc on the Alaska
Peninsula: Alaska Division of Geological & Geophysical Surveys Professional Report 88, 14 p.
2. Bottom Core
4. Top Core
APPENDIX B NEA Soil Sampling Locations and Notes
Soil Survey for Geothermal Tracer Elements
Conducted August 9-10,2006 Amanda Kolker and Ralph M
Datum: NAD83, coordinates are in deg min'secsec
SAMPLE
A 1 A-T2
A1 B-T2
A2A
A2B
A3A
A3B
A4A
A4B
A5A
A5B
A6A-T3
A6 B-T3
A7A
A7B
B6A
B7A
B7B
B8A
B8B
C2A
C2B
C3A
C3B
C4A
C4B
C6A-T5
C6B-T5
C7A
C7B
C8A-T4
C8B-T4
C8C-T4
LAT(N)
58 47'34.9
58 47'35.4
58 46'20.1
58 46'1 9.7
58 45'50.4
58 45'50.3
58 45'04.0
58 45'05.2
58 45'08.4
58 45'08.4
58 44'1 3.5
58 44'1 3.8
58 43'25.1
58 43'24.8
58 42'27.8
58 38'55.6
58 38'55.9
58 40'14.9
by A
58 42'1 1.6
58 42'12.3
58 41'46.1
58 41'46.5
58 41'15.7
next to A
58 39'21 .O
58 39'22.2
58 38'36.2
58 38'36.3
58 38'00.6
58 38'01.4
58 37'59.9
LONG(W) EL(ft) DEPTH NOTES
156 53'59.7
1 56 54'07.1
1 56 49'07.0
1 56 49'07.8
156 46'51.5
1 56 46'50.7
156 43'43.2
1 56 43'43.8
156 40'25.4
156 40'25.0
156 37'40.4
1 56 37'4 1 .9
156 33'59.3
156 33'58.7
1 56 43'37.4
156 37'25.3
156 37'25.3
I56 30'52.7
by A
156 52'52.4
1 56 52'5 1.3
156 50'07.9
156 50'07.5
I56 47'40.3
next to A
I56 41 '38.7
156 41 '53.2
156 38'22.6
1 56 38'24.3
I56 35'12.1
I56 35'12.8
I56 35'12.9
sandy clay loam wlgravel, under tundra 1' thick
sand, from top of butte, exposed
gravel and sand, top of butte
sand
downhill, on slope, seived because of roots
boggy tundra - muddy sand sample
boggy tundra - muddy sand sample
sand
LOTS of organics - took 2 samples - poured distilled H20 over one
on berm, in birches, close to gravel road but uphill
BLM mon. - sand on ridge (dune or manmade?)
50 ft. from A
Pike Lake
blue clay wl brown sand
permafrost
permafrost
in boggy tundra, S smell
in boggy tundra, S smell
smelt hill - on top, gravel exposed knob
1st of 3 sandblows - line up on 240 degree azimuth
3rd of 3 sandblows - very linear
tundra, hi pt near a lake
inside green band ("linear"/"circular"?) - thicker tundra
inside green band ("linear"/"circular"?) - thicker tundra
outside green band