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Home My WebLink AboutGeothermal Resources of the Aleutian ARC 1993GEOTHERMAL RESOURCES OF THE ALEUTIAN ARC By Roman J. Motyka, Shirley A. Liss, Christopher J. Nye, and Mary A. Moorman Professional Report 114 Published by STATE OF ALASKA DEPARTMENT OF NATURAL RESOURCES DIVISION OF GEOLOGICAL & GEOPHYSICAL SURVEYS ney lars aia j aad NEO VANe 1993 : ' RESOURCES GEOTHERMAL RESOURCES OF THE ALEUTIAN ARC By Roman J. Motyka, Shirley A. Liss, Christopher J. Nye, and Mary A. Moorman Professional Report 114 Division of Geological & Geophysical Surveys Cover photo: "Old Faithful" of the Geyser Bight geothermal resource area. When- ever it has been observed (1870, 1948, 1980, and 1988), spring G8, Fairbanks, Alaska shown here at maximum activity, has had an eruption cycle of > 1993 12 minutes. Photo by Shirley Liss. STATE OF ALASKA Walter J. Hickel, Governor DEPARTMENT OF NATURAL RESOURCES Harry A. Noah, Commissioner DIVISION OF GEOLOGICAL & GEOPHYSICAL SURVEYS Thomas E. Smith, State Geologist Division of Geological & Geophysical Surveys publications can be inspected at the following locations. Address mail orders to the Fairbanks office. Alaska Division of Geological University of Alaska Anchorage Library & Geophysical Surveys 3211 Providence Drive 794 University Avenue, Suite 200 Anchorage, Alaska 99508 Fairbanks, Alaska 99709-3645 Elmer E. Rasmuson Library Alaska Resource Library University of Alaska Fairbanks 222 W. 7th Avenue Fairbanks, Alaska 99775-1005 Anchorage, Alaska 99513-7589 Alaska State Library State Office Building, 8th Floor 333 Willoughby Avenue Juneau, Alaska 99811-0571 This publication released by the Division of Geological & Geophysical Surveys, was produced and printed in Fairbanks, Alaska, by Graphic North Printing, at a cost of $14 per copy. Publication is required by Alaska Statute 41, “to determine the potential of Alaskan land for production of metals, minerals, fuels, and geothermal resources; the location and supplies of groundwater and construction materials; the potential geologic hazards to buildings, roads, bridges, and other installations and structures; and shall conduct such other surveys and investigations as will advance knowledge of the geology of Alaska.” ii CONTENTS Introduction 1 Regional geology 1 Volcanoes 4 Hydrothermal systems 4 Thermal waters 5 Fumaroles 8 Resource base 10 Present use 11 Future use 11 Acknowledgments 12 References cited 12 Figures 1. Location map of active volcanoes of the Aleutian arc 2 2. Location map of geothermal sites in the Aleutian arc 3 3. Ternary diagram of relative CI, HCO,,, and SO,? contents of Aleutian arc thermal waters based on weight 6 4. Ternary diagram of relative Na*-K*-Mg* contents of Aleutian arc thermal waters based on weight 7 5. Plot of stable isotope composition of meteoric waters in the Aleutian arc. Standard mean ocean water (SMOW), Bering Sea waters, Gulf of Alaska waters, and Craig (1961) meteoric waterline shown for comparison 9 6. Plot of stable-isotope composition of thermal waters in the Aleutian arc. Craig (1961) meteoric waterline shown for comparison 9 Tables—See sheet 4 for tables 1-8 1. XN 8. Locations of geothermal sites in the Aleutian arc, from west to east. Thermal manifestations listed in order of importance Quaternary volcanoes of the Aleutian arc Water chemistry, isotopic analyses, and geothermometry of thermal waters in the Aleutian arc Chemistry and geothermometry of gases emitted from geothermal fumarole fields and chloride thermal spring systems in the Aleutian arc Chemistry of gases emitted from fumaroles associated with volcanic vents in the Aleutian arc Isotopic analyses of gases emitted from geothermal fumarole fields, thermal springs, and fumaroles associated with volcanic vents in the Aleutian arc Estimates of reservoir temperatures, volumes, and energy stored in identified hydrothermal systems Additional sites suspected of having hydrothermal systems Sheets—In pocket PYNYP Geothermal Resources of the Aleutian Arc, Alaska, Part 1—Western Arc Geothermal Resources of the Aleutian Arc, Alaska, Part 2—Central Arc Geothermal Resources of the Aleutian Arc, Alaska, Part 3—Eastern Arc Geothermal Resources of the Aleutian Arc, Alaska, Part 4—Supplemental data iii GEOTHERMAL RESOURCES OF THE ALEUTIAN ARC by Roman J. Motyka, Shirley A. Liss, Christopher J. Nye, and Mary A. Moorman INTRODUCTION Quaternary Aleutian volcanism extends for over 2,500 km, from Buldir Island on the west to Mount Hayes on the east (fig. 1). This belt of volcanic activity lies immediately north of the Aleutian trench, a convergent boundary between the North American and Pacific lithospheric plates. The convergence of these plates has produced one of the most seismically active zones in the world. Active volcanic systems, shallow, magmatically heated rock, and deep fracture and fault systems have combined to create favorable settings for the development of hydrothermal systems. We have tentatively identified at least 56 sites in the Aleutian arc (fig. 2) where surface expressions of these hydrothermal systems, such as thermal springs and fumaroles, are found (table 1, sheet 4). Many of these sites were first reported by Waring (1917) and later summarized in Miller (1973), White and Williams (1975), Markle (1979), Muffler (1979), Turner and others (1980), and Motyka and others (1983a). This report is based on studies conducted by the Alaska Division of Geological & Geophysical Sur- veys (DGGS) between 1980 and 1988, frequently in cooperation with investigators from the University of Alaska Fairbanks. Our earlier reconnaissance stud- ies concentrated on the geochemistry of thermal spring waters and fumaroles. Later site-specific stud- ies included geological and geophysical surveys and additional fluid geochemistry investigations. Explor- atory geothermal wells were drilled at Makushin and Summer Bay on northern Unalaska Island. Our initial survey (1980) covered the area between Atka Island in the central Aleutians and Becharof Lake on the Alaska Peninsula (Motyka and others, 1981). We extended this coverage west to Adak Island in 1981 (Motyka, 1983) and east to Mount Spurr in 1982. Several sites reported but not substantiated by Waring could not be found by DGGS and therefore are not included in this report (Motyka and others, 1981). Some sites not previously reported, or only briefly mentioned, were investigated by DGGS and are described on the map plates. We did not visit sites west of Adak Island or many of the more remote sites between Adak Island and Mount Spurr. Information on these sites was obtained from published and unpublished sources. We maintain a bibliography of all references relevant to geothermal resources in Alaska. The bibliography is periodically updated and is available to the public (Liss, Motyka, and Nye, 1988). REGIONAL GEOLOGY This summary of the geologic setting of the Aleutian arc is taken largely from Kienle and Nye (1990). Aleutian arc volcanism is the result of active subduction of the Pacific lithospheric plate beneath the North American lithospheric plate. The 3,400-km- long Aleutian trench that extends from the northern end of the Kamchatka trench to the Gulf of Alaska marks the boundary between the two plates. The Quaternary Aleutian arc, which spans about 2,500 km of the Alaska mainland and the Aleutian Islands, is built on continental crust in the east and on oceanic crust in the west. The eastern and western parts of the arc are divided by the Bering Sea continental shelf, which intersects it near Unalaska, Akutan, and Unimak Islands. The volcanic front is sharp and closely aligned with the 100-km depth contour to the Wadati-Benioff zone (Jacob, 1986; Kienle and others, 1983). The island-forming Quaternary volcanoes of the oceanic part of the arc were built on the Aleutian Ridge, which rises 3,000 m above the Bering Sea floor to the north and more than 6,000 m above the Aleu- tian trench to the south. Scholl and others (1987) describe three rock sequences that record the major evolutionary growth of the Aleutian Ridge: (1) Arc volcanism in early to middle Eocene time (55 to 50 Ma) formed most of the ridge. The lower series consists of igneous and volcaniclastic basement rocks. (2) Growth by volcanism subsided during Oligocene and Miocene time, when erosional processes buried the ridge flanks with thick marine sedimentary units. Plutonic activity increased during Oligocene through early Miocene time (35 to 8 Ma). (3) Pliocene and Quaternary age (younger than 5.3 Ma) slope-mantling and crustal basin sedimentary © °o RUSSIA ALASKA Sheet 3 s o 60° Sheet 1 Sheet 2 7 LOCATION INDEX Figure 1. Active volcanoes of the Aleutian arc. Numbers keyed to table 2, sheet 4. pI] 14oday jouorssaforg o. 2 RUSSIA ALASKA Sheet 3 ~ ne) } 60° Sheet 1 Sheet 2 ° r ™ A 47,48,49, @ ef 44,45,41 L oe Oye oP” LOCATION INDEX Figure 2. Geothermal sites in the Aleutian arc. Site numbers are keyed to table 1, sheet 4. oy upynaly ayl fo saznosay [DULLaYyJoaH 4 Professional Report 114 sequences that unconformably overlie the older units form the upper series. Regional subsidence and block faulting affected the ridge crest in late Cenozoic time. Subsequent wave erosion created a prominent summit platform. The Quaternary volcanic belt developed near the northern edge of this platform. Whereas no terrestrial rocks older than Tertiary have been found in the oceanic part of the arc, terres- trial rocks of Mesozoic and Paleozoic age make up the basement of the continental part of the arc on the Alaska Peninsula and in the Cook Inlet region (Burk, 1965; Beikman, 1980). VOLCANOES The Aleutian arc includes 89 Quaternary volcanoes, of which 44 have been historically active (Simkin and others, 1981) (table 2, sheet 4). At least 21 of the Quaternary volcanic centers have calderas (Miller and Smith, 1987), and as many as 19 of these may have formed in Holocene time. Aleutian arc volcanoes are intimately related to the subduction of the Pacific Plate beneath the North American Plate. Material from the subducted slab mixes with material from the astherospheric mantle to produce primary magmas. However, the relative distribution is unknown. Aleutian magmas have major and trace element and isotopic compositions broadly typical of relatively mature arcs built on oceanic or thin continental crust (Kienle and Nye, 1990). They are dominantly medium potassium basalts through dacites with both calc-alkaline and tholeiitic affinities. Rhyolite is volumetrically minor and occurs as glass shards, ash flows, and small pods and domes on the flanks of a few volcanoes. Aleutian volcanic rocks are typically porphyritic, with plagioclase almost always dominant. Mafic lavas usually contain olivine and clinopyroxene phenocrysts, whereas intermediate and silicic lavas usually contain orthopyroxene and clinopyroxene. Amphibole phenocrysts are less common, but do occur throughout the compositional range of Aleutian calc-alkaline magmas. Biotite, which is even more rare, has been reported from a few eruptive centers. Magmas from the eastern part of the arc are domi- nantly calc-alkaline andesite; tholeiitic magmas are rare. Magmas from the central part of the arc are domi- nantly tholeiitic basalt and basaltic andesite. The central part of the arc also contains the most volumi- nous volcanoes. Volcanoes in the western part of the arc erupt calc-alkaline and tholeiitic basalt, basaltic andesite, and andesite. Table 2 (sheet 4) lists known Quatemary volcanoes of the Aleutian arc and provides information on volcano elevation, current morphology, and eruptive history. It also includes a qualitative estimate of the potential for the presence of a developable hydrothermal resource. Numbers are keyed to the map sheets. HYDROTHERMAL SYSTEMS Thermal springs, fumaroles, and heated ground are the surface manifestations of subsurface hydrothermal systems. In such systems, heat is transported primarily by convective circulation of fluids (usually water or steam) rather than by thermal conduction through solid rock. Hydrothermal systems have been classified as either hot-water or vapor- dominated, depending on the dominant pressure- controlling fluid in fractures and pores. Most explored systems in the world are hot-water dominated (White and Williams, 1975). Vapor-dominated systems are relatively rare. Although fumarole fields are associated with many Aleutian arc thermal sites, these steam-phase manifestations are probably surface expressions of shallow, vapor-dominated systems created by boiling of a deeper hot-water system (for example, Makushin [Motyka and others, 1983b; Motyka and others, 1988]). Hot-water convection systems are divided into three categories based on reservoir temperatures: high temperature (>150°C); intermediate temperature (90 to 150°C); and low temperature (<90°C) (Muffler, 1979). The temperature of the hottest spring or fuma- role, the estimated convective heat discharged at the surface by spring flow, the total dissolved solids in the waters from the principal spring, and the estimated reservoir temperature based on chemical geothermometry for each thermal site are shown on the map sheets. A dash indicates no data for that en- try. Site numbers are keyed to table 1 (sheet 4), which lists location by geographic coordinates. In addition, brief site descriptions accompany the diagrams. Larger scale insets (1:250,000) are provided for sev- eral areas that were more intensively investigated. Chemical geothermometers are based on temperature-sensitive chemical reactions in hydrothermal fluids and are commonly used to estimate subsurface temperatures at sites where drilling data are not available. These reactions may control either the absolute amount of an element (for Geothermal Resources of the Aleutian Arc 5 example, silica), the relative concentrations of elements (for example, cations), or the fractionation of isotopes. The estimated reservoir temperatures derived from geothermometry calculations may represent actual subsurface temperatures if several assumptions about the nature of an individual hydrothermal system are satisfied. For a review of chemical and isotopic geothermometers, see Fournier (1981). THERMAL WATERS Only four thermal-spring sites in the Aleutian arc are located near population centers. These include Kiguga (site 4, sheet 1) and Andrew Bay (site 5, sheet 1), near the Adak naval station; Summer Bay (site 21, sheet 2), near Unalaska village; and Hot Springs Bay (site 23, sheet 2), near Akutan village. False Pass (site 28, sheet 2) and Port Moller (site 35, sheet 3) thermal springs are located within 12 km of small villages. Sites 7, 8, and 9 (sheet 1) on northeast Atka Island lie about 15 km north of Atka village; the Makushin geothermal area (site 20, sheet 2) is located 20 km west of Unalaska village; while Nikolski, the closest village to Geyser Bight (site 13, sheet 2), is located 40 km west of this geothermal area. The remaining thermal springs are located in remote areas, commonly near tidewater or on the flanks of active volcanoes. Table 3 (sheet 4) provides chemical analyses of water from the principal thermal spring, geothermal well, or crater lake at each visited site. Plots of major anions (Cl-, HCO3", and SO4°2) provide a convenient method of classifying thermal waters based on the dominant anion (fig. 3) and can also provide insights into the origin of the thermal water. In figure 3, compositional ranges are indicated for several typical thermal-water groups (Giggenbach and Goguel, 1989). Acid “volcanic” waters are formed when volcanic crater lakes or shallow groundwater absorb high-temperature, sulfur- and chlorite-rich volcanic gases (for example, sites 48, 51, and 56a, sheet 3). Sulfate-rich “‘steam-heated” waters form when shallow groundwater absorbs steam, hydrogen- sulfide, and other gases produced by boiling of a deeper hot-water system (for example, sites 6, 7, 8, and 9, sheet 1; site 22, sheet 2). Neutralization of these generally acidic waters through subsurface water- rock-gas interactions can produce waters enriched in bicarbonate (for example, sites 19 and 20, sheet 2). High-sulfate, steam-heated waters are usually only encountered at higher elevations of a geothermal field. Geothermometers are generally not suitable for application to these steam-heated waters. Neutral, low-sulfate, high-chloride waters that lie along or near the Cl--HCO3° axis, close to the Cl” corner (fig. 3) are considered to be directly related to deep thermal waters and are best suited for estimating reservoir temperatures. High bicarbonate concentrations indicate the waters are derived from the margins of a thermal area, whereas waters containing near-equal proportions of anions are probably of mixed origin. Considerable caution is required in applying geothermometers to these waters. The Nat-K*-Mg?? diagram (fig. 4) and its application to geothermal systems are described by Giggenbach (1988). The “full-equilibrium” curve represents water compositions in full equilibrium with the mineral system albite-potassium feldspar- muscovite-clinochlore-silica at the temperatures indicated. The boundary between partially equilibrated and immature waters is somewhat arbitrary and serves only as a rough guide. The isotherms correspond to equilibrium between the pairs potassium-sodium and potassium-magnesium at various temperatures as derived by Giggenbach (1988). Magnesium concentrations in thermal waters are highly temperature dependent; hotter temperatures favor magnesium depletion through hydrothermal reactions. In mature thermal waters, magnesium is commonly present in trace amounts only. Water from Makushin Well ST-1 (site 20a, sheet 2) plots close to the full equilibrium line, while Geyser Bight thermal spring waters (sites 13a,b,c, sheet 2) and several other chloride thermal spring waters trend toward the magnesium corner in the partial-equilibrium field. This trend reflects the greater speed with which the potassium and magnesium conceutrations adjust to changes in temperature as compared with potassium and sodium as the water ascends to the surface. Several thermal waters plot in the compositional range marked “immature waters” near the magnesium corner. For some, magnesium may be added by dissolution of minerals in the shallow environment as the waters cooled conductively or mixed with cold groundwater (for example, sites 23, 28, and 32, sheet 2). The remaining waters analyzed in this study are typically either acid (sites 6, 7, 8, and 9, sheet 1; sites 22, 48, 51, and 56a, sheet 3) or carbon-dioxide-rich (sites 18 and 19, sheet 2; sites 40, 44, and 56b, sheet 3). 6 Professional Report 114 Because these waters are usually not in chemical equilibrium application of geothermometers to these “immature” thermal waters may be inappropriate and interpreting temperatures based on the water’s chemical composition must be carefully considered. We have applied silica and several cation geothermometers to Aleutian arc thermal water chemistry (table 3, sheet 4) (see Fournier, 1981, fora review of geothermometry). These geothermometers are most reliable for “chloride” thermal waters and are less certain for “mixed and peripheral” waters. They are probably not valid for steam-heated and “acid-volcanic” waters. The potassium-magnesium geothermometer is useful for evaluating low- temperature waters (Giggenbach, 1988), while the magnesium-lithium geothermometer was developed specifically for sedimentary formation waters (Kharaka and Mariner, 1989). The rate of the sulfate- water oxygen isotope exchange reaction is very slow compared with silica solubility and cation exchange reactions (McKenzie and Truesdell, 1977). Therefore, temperatures predicted by the sulfate-water oxygen isotope geothermometer serve as potential indicators of temperatures at greater depths. The results of stable isotope analysis of 94 meteoric stream waters and precipitation collected in the Aleutian arc are shown in figure 5. Linear regression analysis shows that the best fit to these points is nearly identical to Craig’s meteoric water line (1961). Also plotted are values for Bering Sea waters, Gulf of Alaska waters, and Standard mean ocean water (SMOW). Values for stable isotope compositions of Aleutian arc thermal waters are plotted in figure 6. The coincidence of most thermal- water values with meteoric-water values indicates that meteoric waters constitute the primary source of recharge for Aleutian arc hydrothermal systems. Some SO,” Figure 3. Relative Cl", HCO3", and SO4? contents of Aleutian arc thermal waters on weight (mg/kg) basis (after Giggenbach and Goguel, 1989). Numbers re- fer to thermal-spring sites shown on sheets and listed in table 1 (sheet 4). Geothermal Resources of the Aleutian Arc thermal waters have 8!80 displaced +1 to +2 per mil from local meteoric water values (for example, sites 13, 20, sheet 2; fig. 6). Such positive shifts have been attributed to oxygen-18 exchange between the deeply circulating meteoric waters and reservoir wallrocks. The degree of shift depends on temperature and on the rock/water ratio (Truesdell and Hulston, 1980). Springs 5, 41, and perhaps 40 may have been partially derived from connate brines. Such waters are typically enriched in deuterium and oxygen-18 (Truesdell and Hulston, 1980). The relatively heavier stable-isotope composition of the boiling acid-sulfate waters at springs 7 and 22 is probably attributable to evaporative effects: the lighter isotopes fractionate into the vapor phase. Na‘*/1000 Full 60 equilibrium %Na*/1000 Analysis of gas emissions collected from chloride thermal spring sites in the Aleutian arc are given in table 4 (sheet 4). Thermal-spring gases were collected by immersing a funnel connected to an evacuated flask over a train of gas bubbles emerging from the hot spring or pool. When water in the funnel was displaced by gases, a stopcock was opened and the gases were collected in the evacuated flasks. Methane is the primary component at Cold Bay (site 31, sheet 2) and Port Moller (site 35, sheet 2), whereas carbon-dioxide predominates at Andrew Bay (site 5, sheet 1), lower Glacier Valley (site 18, sheet 2), and Gas Rocks (site 41, sheet 3). Nitrogen is the major component at the remaining springs. The nitrogen- argon ratios at most sites are close to the atmospheric MZ K*/100. @ DOS Figure 4. Relative Na*-K*-Mg*? contents of Aleutian arc thermal waters on weight (mg/kg) basis (after Giggenbach and Goguel, 1989). Na-K-Mg temperatures from Giggenbach (1988). Numbers refer to thermal-spring sites shown on sheets and listed in table 1 (sheet 4). ratio (~84) or lie between the air ratio and air- saturated groundwater (~34) ratios, indicating that nitrogen and argon are largely derived from air. Because of oxidation reactions, oxygen is usually only present in very minute quantities in equilibrated hydrothermal fluids. Its presence in measurable amounts indicates air contamination. Except for Hot Springs Bay (site 23, sheet 2), the gas emissions are commonly depleted in hydrogen sulfide and hydrogen when compared with fumarolic gases (table 4, sheet 4). Oxidation and other reactions probably removed these gases from the thermal water, and methane is probably of thermo-biogenic origin. We suspect that the carbon dioxide is mostly derived from magmatic sources although some carbon dioxide may be thermo-biogenic in origin. Most Aleutian arc chloride thermal springs probably originate as meteoric waters that circulate along fracture and fault systems produced by tectonic forces associated with the collision of the Pacific and North American lithospheric plates. Waters that circulate through the fractures are heated by thermal conduction from the surrounding rock and, in some cases, by direct absorption of volcanic steam and gases. Near active volcanism, heat is supplied by magmatic sources; at locations farther from volcanoes, heat is supplied by the regional heat flux. Net enthalpy per kilogram of discharge from each spring area was calculated as the difference between the discharge temperature and an assumed reference temperature of 10°C at the land surface. The total heat discharged at the surface by thermal springs in the Aleutian arc is conservatively estimated at 78 MW. FUMAROLES Fumaroles are found at numerous geothermal sites in the Aleutian arc. In many cases, they are the dominant surface manifestation of the hydrothermal resource (table 1, sheet 4). We distinguish between “geothermal” and “volcanic” fumaroles primarily by their spatial association with active volcanic vents. In the Aleutain arc, “geothermal” fumaroles typically lie at mid-elevations on the flanks of volcanoes, relatively distant from an obvious volcanic vent. The fumaroles usually occur in clusters that cover several to tens of hectares in area, and commonly are associated with steam-heated or acid-sulfate springs. Hydrothermal alteration is usually widespread and ubiquitous, indicating long-term fumarolic activity. In some cases, chloride thermal springs may emerge Professional Report 114 at lower elevations (for example, sites 13, 19, and 22, sheet 2). Aleutian arc “geothermal” fumaroles are typically at boiling point temperatures. Carbon dioxide is the dominant dry-gas component, and hydrogen sulfide is the only sulfur gas present (table 4, sheet 4). We presume these fumaroles are the surface expressions of boiling, subsurface, liquid- dominated hydrothermal systems, although at a few locations in the world such fumaroles reflect deep, vapor-dominated systems (for example, Geysers, California, and Lardellero, Italy). Although magma is probably the heat source and probably contributes carbon dioxide, sulfur gases, and halogens to the overlying liquid-dominated hydrothermal systems, “geothermal” fumarolic gas compositions are controlled by water-gas-rock interactions and boiling within the hydrothermal reservoir. In contrast, fumaroles associated with volcanic vents are commonly superheated and may emit sulfur-dioxide and halogen-rich gases (table 5, sheet 4). Steam content is highly variable, and in some cases sulfur gases equal or exceed carbon dioxide as the dominant dry-gas component. “Volcanic” fumaroles are located on the floors, rims, and flanks of active craters (sites 17, sheet 2; sites 43, 51, and 56, sheet 3); on active lava domes (sites 44 and 52, sheet 3); and on the cones and summits of active volcanoes (sites 16, sheet 2; sites 46, and 47, sheet 3). Their location and correlation with volcanic activity and gas chemistry suggest a more direct connection to magmatic sources with fumarolic compositions controlled by magma- and rock-gas interactions (sites 51 and 52, sheet 3). In some cases, meteoric water may flood and quench the surface of residual magma to create a boiling hydrothermal layer and give rise to “geothermal” gas emissions (sites 17, sheet 2; site 56, sheet 3). Although it is unlikely that volcanic vents will be commercially developed for geothermal energy, “volcanic” gas samples provide useful information on the magmatic heat sources that may underlie geothermal systems and serve as a reference for comparison with “geothermal” gas emissions. Because oxygen in fumarole gases should be virtually nonexistent, any oxygen detected in our samples is attributed to air contamination. Most “geothermal” and “volcanic” fumaroles have nitrogen-argon ratios that lie between atmospheric (~84) and air-saturated groundwater (~34) ratios, indicating an atmospheric origin for the nitrogen and argon, with oxygen removed in oxidation reactions. Geothermal Resources of the Aleutian Arc TY eet O Aleutian meteoric waters 4 Bering Sea waters -20 v Gulf of Alaska waters SMOW = -40 = -60 bey o o -80 A -100 -120 —Craig MWL -140 OOS tte Aleutian-Alaska Peninsula MWL -160 ! ! ! | ! | 1 1 ! ! ! -20 -18 -16 -14 -12 1 8 6 4 -2 O 2 4 6 O, per mil Figure 5. Stable isotope composition of meteoric waters in the Aleutian arc. Standard mean ocean water (SMOW), Bering Sea waters, Gulf of Alaska waters, and Craig (1961) meteoric waterline shown for comparison. Dotted line represents linear regression fit to Aleutian and Alaska Peninsula meteoric water data. 20 T a — + — uy T T Tr T T of © Fumarole condensates 6D, per mil 8 -100 + Thermal waters © Chloride -120 4 Brines V_ Mixed and peripheral -140 v : @ Steam-heated 56 Craig MWL @ = Acid-sulfate -160 1 1 ri 1. 1 . . 1 1 —20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 2 4 18 : 6 O, per mil Figure 6. Stable-isotope composition of thermal waters in the Aleutian arc. Craig (1961) meteoric waterline shown for comparison. Numbers refer to thermal-spring sites shown on sheets and listed in table 1 (sheet 4). 10 Professional Report 114 In some cases, the nitrogen-argon ratio substantially exceeds the atmospheric ratio. The excess nitrogen may be derived from a magmatic source. A magmatic influence on the Aleutian arc fumarole fluids is supported by helium isotope ratios, where R/Ra is the ratio of 3He/*He in the sample to 3He/4He in the atmosphere (table 6, sheet 4). This ratio ranges from 6.5 to 8.0 for Aleutian arc “volcanic” fumaroles compared to 8 + 1 for mid-ocean-ridge basalts (Poreda and Craig, 1989). Values for Aleutain arc “geothermal” fields range from 2.1 at Port Moller (site 35, sheet 3) to 7.5 at Geyser Bight (site 13, sheet 2). The lower values are probably caused by mixing of varying proportions of crustal helium (R/Ra<0.02) with mantle-derived helium. Although a few sites have isotopic values of 8'3C-CO, that lie within the range of mantle-derived carbon dioxide (-4 to -9 per mil), 8!3C-CO, values for most Aleutian arc fumaroles are lighter than mantle carbon dioxide, but lie within the range for marine organic carbon (-7 to -17 per mil; Truesdell and Hulston, 1980; table 6, sheet 4). These ranges allow for the possibility that Aleutian arc fumarolic carbon dioxide is a mixture of mantle carbon diox- ide and carbon dioxide derived from marine-organic sources. Using empirical data, D’Amore and Panichi (1980) devised a gas geothermometer to estimate geothermal reservoir temperatures based on the proportions of carbon dioxide, hydrogen sulfide, hydrogen, and methane in geothermal fumarolic gases. The geothermometer, which assumes a gas-water-rock equilibrium in a hydrothermal system and preservation of this “deep” equilibrium composition in the emergent gases, was applied to geothermal fumarolic gases using an assumed partial pressure for carbon dioxide of 1 bar (table 4, sheet 4). These temperature estimates must be treated cautiously because gas-rock interactions and oxidation reactions with entrained air can affect gas composition, particularly hydrogen and hydrogen sulfide, during fluid ascent and sampling. To circumvent some of the problems of multi-component geothermomters, Giggenbach and Goguel (1989) devised gas geothermometers based on isomolar concentrations of hydrogen and carbon dioxide with respect to argon. Argon was chosen because it is inert and because itis introduced almost exclusively with the meteoric water component that forms the bulk of most geothermal waters. Results of applying the hydrogen-argon and carbon dioxide-argon geothermometers to Aleutian arc geothermal fumaroles are shown in table 4 (sheet 4). Temperatures predicted by these two geothermometers are similar, but generally lower than estimates obtained from the D’Amore and Panichi (1980) geothermometer. The highest temperatures estimated by gas geothermometry are 300°C (Milky River, site 9, sheet 1; upper Glacier Valley, site 19, sheet 2). These geothermal geothermometers were not applied to volcanic vent fumaroles because of uncertainties about the environment of subsurface volcanic gas equilibration. Subsurface temperatures at these sites probably exceed 150°C. Where sulfide and halogen gases are emitted from fumarolic vents, gas source temperatures probably exceed 350°C. Methods for reconstructing subsurface volcanic gas assemblages and determining equilibrium tempera- tures from fumarolic gas compositions have been developed by Reed and Symonds (1992) and Giggenbach (1987). These methods have been applied to Augustine (site 52, sheet 3) 1984 samples (Kodosky and others, 1991; Te~800°C); post-eruptive 1986 Augustine gas samples (Symonds and others, 1990; Te>1,200°C); and to samples from Katmai National Park (Sheppard and others, 1992; Te>600°C). RESOURCE BASE We evaluated the Aleutian arc geothermal resource base according to methods developed by White and Williams (1975) and Muffler (1979). Our expanded data base, acquired since 1979, allowed us to identify several hydrothermal systems that were not reported in earlier assessments of the geothermal resources of the Aleutian arc. At least 14 sites potentially host high-temperature (>150°C) hydrothermal reservoirs; four sites host intermediate- temperature systems (90 to 150°C); and six sites host low-temperature systems (<90°C; table 7, sheet 4). Geothermal drilling in 1983 and 1984 confirmed a liquid-dominated hydrothermal resource of at least 195°C at Makushin Valley (site 20, sheet 2). Reservoir temperatures for Makushin Valley and the remaining geothermal sites were estimated using applicable geothermometers (table 7, sheet 4). Mean reservoir temperatures are based on the average of minimum, maximum, and most likely temperatures determined by geothermometry, geothermal well temperature (sites 20 and 21, sheet 2), and thermal-spring vent temperature (site 28, sheet 2) following methods similar to those described in Brook and others (1979). Geothermal Resources of the Aleutian Arc 11 At least 20 other sites probably have reservoirs with temperatures >150°C (table 8, sheet 4), but development of these sites is unlikely because they are located on or near active volcanic vents or in national conservation units. The amount of thermal energy stored in the Accessible Resource Base as defined by Brook and others (1979) is estimated at 42x1018 J for the 14 high-temperature systems; 3.8x10!8 J for the four intermediate-temperature systems; and 0.9x10!8 J for the six low-temperature systems (table 7, sheet 4). For T>90°C, these estimates are based on an assumed mean reservoir thickness of 1.67 km3 (Mariner and others, 1978). Estimates of reservoir area are based on the surface expression of the geothermal resource. Where a single group of springs or fumaroles are the only evidence of a reservoir, the subsurface reservoir volume is estimated to be 3.3 km3 (Mariner and others, 1978; Brook and others, 1979) and 1 km3 for T<90°C (Sorey and others, 1983). Heat energy in the reservoir is referenced to 15°C as defined by Brook and others (1979). Wellhead thermal energy, available work, electrical energy, and beneficial heat were calculated using methods described in Brook and others (1979). We estimate that the combined 30-yr electric-power- production potential for the 14 high-temperature sites >1,000 Mw. A much greater store of geothermal energy resides in shallow magma chambers and hot rock beneath volcanic edifices (table 2, sheet 4), but estimates of the heat content of these magmas are highly speculative. Using estimates of high-level magma-chamber volumes and radiometric ages of the youngest related volcanism, Smith and Shaw (1975; 1979) estimate that 12x 102! J of thermal energy remains in Aleutian arc igneous systems. Given the highly speculative nature of estimating igneous-related thermal energy and the improbability that technological advances will allow commercial development of such resources in the foreseeable future, further refinement of these estimates is not justified. PRESENT USE A test well drilled near the head of Makushin Valley (site 20, sheet 2) on northern Unalaska Island, as part of a state-funded geothermal exploration program, successfully produced 195°C water from a depth of 590 m (Republic Geothermal, Inc., 1983, 1984, 1985; Motyka and others, 1988). Battle Mountain Gold Company purchased the land and leased the geothermal resource to OESI Power Corporation (formerly Ormat Energy, Inc.). The Alaska Energy Authority has analyzed OESI’s plans to develop a 12 MW geothermal power plant at the site. The project would provide base load power to the residents of the city of Unalaska and to the fishing and shipping industry at the international Port of Dutch Harbor. If developed, Makushin Valley would be the first site in Alaska to use geothermal energy to produce electric power. The state of Alaska has leased two tracts southeast of Mount Spurr to a private company for geothermal development. The lease-holders have announced plans to develop the site for hydroponic gardening, but no action has been taken. During a pilot geothermal-drilling program sponsored by the Alaska Division of Energy and Power Development (now the Alaska Energy Authority), a shallow, warm- water aquifer was delineated at Summer Bay (site 21, sheet 2) at a depth of about 50 m. Unfortunately, the flow rate and resource temperature were too low to use for direct-heat applications. Several scientific studies have been conducted in Katmai National Park as part of the Katmai Sci- entific Drilling Project, an interdisciplinary surface and drilling investigation of the 1912 eruption from Novarupta. The surface phase of the investigation has been completed, and plans call for drilling two core holes into the vent and one through the ash- flow sheet in 1994-95. The drilling must first be ap- proved by the National Park Service following completion of an Environmental Impact Statement. Little or no development has occurred at thermal sites elsewhere in the Aleutian arc, largely because of their remoteness and the costs associated with developing resources in remote localities. Several thermal-spring areas located near villages are used as recreational sites: Andrew Bay (site 5, sheet 1), Hot Springs Bay (site 23, sheet 2), Port Moller (site 35, sheet 3), and False Pass (site 28, sheet 2). Early historic accounts suggest that thermal springs on northeast Atka Island and on Umnak Island may have been used by native populations for recreational and ceremonial purposes. FUTURE USE Most remote thermal sites in the Aleutian arc will probably remain undeveloped, particularly those located within national conservation units. However, 12 Professional Report 114 in addition to Makushin Valley, three sites located near population centers have excellent potential for future development. These include sites on northern Adak Island near the Adak Naval Station, sites on northern Atka Island near the Atka village, and Hot Springs Bay, near Akutan village. Development of the latter site is particularly attractive because of its accessibility from the sea and its proximity (4 km) to Akutan Harbor and village. Other sites that warrant consideration for future development are the Geyser Bight geothermal area on Umnak Island, Glacier Valley in the Makushin geothermal area, and the Mount Spurr area, west of Anchorage. Land at these sites is owned by Native corporations or by the state of Alaska. High-temperature (T>150°C) hydrothermal systems that are capable of producing electric power have been identified at each of these sites. ACKNOWLEDGMENTS We thank Eugene Wescott, Donald Turner, John Reeder, Robert Poreda, Malcolm Robb, and many others, too numerous to list, for their valuable assistance in performing field work (sometimes under extraordinarily adverse conditions); Cathy Janik, William Evans, John Welhan, and many others who helped perform lab analyses; and our many colleagues for sharing and discussing their ideas on geothermal resources. We also thank Howard Ross and Joseph Moore (University of Utah Research Institute), Milton Wiltse (DGGS), and Robert Forbes (DGGS and University of Alaska, Fairbanks) for their technical reviews and helpful suggestions for improving this report. We wish also to acknowledge Nori Bowman for the cartography of the colored sheets. Funding for this project was provided in part by a grant from the U.S. Department of Energy (Grant DE-FG07- 88ID 12744). Any opinions, findings, conclusions, or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the U.S. Department of Energy. REFERENCES CITED Alaska Volcano Observatory, 1993, Mt. Spurr's erup- tion: EOS, Transactions, American Geophysical Union, v. 74, no. 19, p. 217, 221-222. Ballard, Sanford, Carrigan, C.R., and McConnell, VS., 1991, Shallow conductive component of heat flow near Novarupta Dome, Katmai, Alaska: Geophysical Research Letters, v. 18, no. 8, p. 1529-1532. Barnes, Ivan, and McCoy, G.A., 1979, Possible role of mantle-derived CO, in causing two “phreatic” explosions in Alaska: Geology, v. 7, no. 9, p. 434-435. Beikman, H.M., 1974a, Preliminary geologic map of the southwest quadrant of Alaska: U.S. Geo- logical Survey Miscellaneous Field Studies Map MF-611, scale 1:1,000,000. 1974b, Preliminary geologic map of the southeast quadrant of Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-612, scale 1:1,000,000. 1975, Preliminary geologic map of the Alaska Peninsula and Aleutian Islands: U.S. Geological Survey Miscellaneous Field Studies Map MF-674, scale 1:1,000,000. 1980, Geologic map of Alaska: U.S. Geological Survey, Professional Paper 171, scale 1:2,500,000. Black, R.F,, 1975, Late Quaternary geomorphic pro- cesses: Effects on the ancient Aleuts of Umnak Island in the Aleutians: Arctic, v. 28, no. 3, p. 159-169. Brook, C.A., Mariner, R.H., Mabey, D.R., Swanson, James, Guffanti, Marianne, and Muffler, L.J.P., 1979, Hydrothermal convection systems with reservoir temperatures >90°C, in Muffler, L.J.P., ed., Assessment of geothermal resources of the United States-1978: U.S. Geological Survey Circular 790, p. 18-85. Burk, C.A., 1965, Geology of the Alaska Peninsula- island arc and continental margin, pts. 1, 2, and 3: Geological Society of America Memoir 99, 250 p., 3 pls., scale 1:500,000 and 1:250,000. Byers, F.M., Jr., 1959, Geology of Umnak and Bogoslof Islands, Aleutian Island, Alaska: U.S. Geological Survey Bulletin 1028-L, p. 107-367. Byers, F.M., Jr., and Brannock, W.W., 1949, Volca- nic activity on Umnak and Great Sitkin Islands, 1946-1948: American Geophysical Union Trans- action, v. 30, no. 5, p. 719-734. Casadevall, T.J., 1990, The 1989-1990 eruption of Redoubt Volcano, Alaska: Impacts on aircraft operations in the vicinity of Anchorage [abs.]: American Geophysical Union Transactions, v. 71, no. 43, p. 1701. Coats, R.R., 1950, Volcanic activity in the Aleutian arc: U.S. Geological Survey Bulletin 974-B, p. 1-47. Geothermal Resources of the Aleutian Arc 13 1956a, Geology of northern Adak Island, Alaska: U.S. Geological Survey Bulletin 1028-C, p. 45-67. 1956b, Geology of northern Kanaga Island, Alaska: U.S. Geological Survey Bulletin 1028-D, p. 69-81. 1956c, Reconnaissance geology of some western Aleutian Islands, Alaska: U.S. Geologi- cal Survey Bulletin 1028-E, p. 82-100. 1959, Geological reconnaissance of Semisopochnoi Island, western Aleutian Islands, Alaska: U.S. Geological Survey Bulletin 1028-0, p. 447-519. Craig, H.A., 1961, Isotopic variations in meteoric waters: Science, v. 133, p. 1702. Dall, W.H., 1870, Alaska and its resources: Boston, Lee and Shepard, 627 p. (Reprinted 1970, Arno and New York Times Press, American Environ- mental Studies series.) D’ Amore, Franco, and Panichi, C.R., 1980, Evalua- tion of deep temperature of hydrothermal systems by a new gas geothermometer: Geochimica et Cosmochimica Acta, v. 44, p. 549-556. Eakins, G.R., 1970, Mineralization near Stepovak Bay, Alaska Peninsula, Alaska: Fairbanks, Alaska Division of Mines and Geology, Special Report 4,12p. Fenner, C.N., 1930, Mount Katmai and Mount Mageik: Zeitschrift fiir Vulkanologie, v. 13, p. 1-24. Foillac, C., and Michard, G., 1981, Sodium/lithium ratio in water applied to geothermometry of geo- thermal reservoirs: Geothermics, v. 10, no. 1, p. 55-70. Fournelle, John, 1990, Shishaldin, Isanotski, and Roundtop Volcanoes, in Wood, C.A., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cambridge University Press, p. 48-50. 1991, Geology and geochemistry of Fisher Caldera, Unimak Island, Aleutians: Initial results {abs.]: American Geophysical Union Trans- actions, v. 71, no. 43, p. 1698-1699. Fournier, R.O., 1981,Application of water chemistry to geothermal exploration and reservoir engineering, in Rybach, L., and Muffler, L.J.P., eds., Geothermal systems: Principles and case histories: New York, Wiley, p. 109-143. Fournier, R.O., and Potter, R.W. II, 1979, A magnesium correction for the Na-K-Ca geothermometer: Geochimica et Cosmochimica Acta, v. 43, p. 1543-1550. 1982, An equation correlating the solu- bility of quartz in water from 25° to 900° C at pressures up to 10,000 bars: Geochimica et Cosmochimica Acta, v. 46, p. 1969-1973. Fritz, Peter, and Fontes, J. Ch., 1980, eds., Handbook of environmental isotope geochemistry, v. 1: New York, Elsevier, 545 p. Giggenbach, W.F., 1987, Redox processes govern- ing the chemistry of fumarolic gas discharges from White Island, New Zealand: Applied Geochemistry, v. 2, p. 143-162. 1988, Geothermal solute equilibria - derivation of Na-K-Ca_geoindicators: Geochimica et Cosmochimica Acta, v. 52, p. 2749-2765. Giggenbach, W.F,, and Goguel, R.L., 1989, Collec- tion and analysis of geothermal and volcanic water and gas discharges: Petone, New Zealand, Department of Science and Industrial Research, Chemistry Division, Report CD 3401, 81 p. Grewingk, C., 1850, Beitrag zur Kenntnisse der orographischen und _ geognostischen Beschaffenheir de Nordwest-Kuste Amerikas mit den aliegenden Inseln: Verhandlungen der Russich-Kaiserlichen Mineralogischen Gesellschalt zur St. Petersburg, Jahrgan 1848 ung 1849, p. 76-342. Griggs, R.F., 1922, The Valley of Ten Thousand Smokes: Washington, D.C., National Geographic Society, 340 p. Hildreth, Wes, 1990, Mageik, Trident, Novarupta, Falling Mountain, Cerberus, Katmai, and Griggs Volcanoes, in Wood, C.A., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cambridge University Press, p. 67-72. Hrdlicka, A., 1945, The Aleutian and Commander Islands and their inhabitants: Philadelphia, Wister Institute of Anatomy and Biology, 630 p. Jacob, K.H., 1986, Seismicity, tectonics, and geohazards of the Gulf of Alaska regions, in Hood, D.W., and Zimmerman, S.T., eds., The Gulf of Alaska, physical environment and biological resources: Washington, D.C., U.S. Department of Commerce, National Oceanic and Atmospheric Administration, and other organizations, U.S. Department of the Interior (Minerals Management Service), p. 145-184. Juhle, R.W., 1955, Iliamna Volcano and its basement: U.S. Geological Survey Open-file Report 55-77, 74 p. 14 Professional Report 114 Katzenstein, A.M., and Whelan, J.A., 1985, Geother- mal potential of Adak Island, Alaska: China Lake, California, Naval Weapons Center, NWC TP 6676, 92 p. Keith, T.E.C., 1991, Fossil and active fumaroles in the 1912 eruptive deposits, Valley of Ten Thou- sand Smokes, Alaska: Journal of Volcanology and Geothermal Research, v. 45, no. 3-4, p. 227-254. Keith, T.E.C., Thompson, J.M., Hutchinson, R.A., White, L.D., 1992, Geochemistry of waters in the Valley of Ten Thousand Smokes region, Alaska: Journal of Volcanology and Geothermal Research, v. 49, no. 2, p. 209-231. Keller, A.S., and Reiser, H.N., 1959, Geology of the Mt. Katmai area, Alaska: U.S. Geological Sur- vey Bulletin 1058-G, p. 261-298. Kennedy, G.C., and Waldron, H.H., 1955, Geol- ogy of Pavlof Volcano and vicinity, Alaska: U.S. Geological Survey Bulletin 1028-A, p. 1-18. Kharaka, Y.K., and Mariner, R.H., 1989, Chemical geothermometers and their application to formation waters from sedimentary basins, in Naeser, N.D., and McCulloch, T.H., eds., Thermal history of sedimentary basins: New York, Springer-Verlag, p. 99-117. Kienle, Jurgen, 1990, Ukinrek maars, Augustine Volcano, and Buzzard Creek volcanics, in Wood, C.A., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cambridge University Press, p. 65-66, 79-80, 85-86. Kienle, Jurgen, 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, no. 1, p. 11-37. Kienle, Jurgen, and Nye, C.J., 1990, Volcano tecton- ics of Alaska, in Wood, C.A., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cambridge University Press, p. 8-16. Kienle, Jurgen, and Swanson, S.E., 1983, Volcanism in the eastern Aleutian arc: Late Quaternary and Holocene centers, tectonic setting, and petrology: Journal of Volcanology and Geothermal Research, v. 17, nos. 1-4, p. 393-432. Kienle, Jurgen, Swanson, S.E., and Pulpan, Hans, 1983, Magmatism and subduction in the eastern Aleutian arc, in Shimozuru, D., and Yokoyama, I, eds., Arc volcanism: physics and Tectonics: Tokyo, Terra Scientific Publishing Company, p. 29, 41. Kodosky, L.G., 1989, Surface mercury geochemis- try as a guide to volcanic vent structure and zones of high heat flow in the Valley of Ten Thousand Smokes, Katmai National Park, Alaska: Journal of Volcanology and Geothermal Research, v. 38, no. 3/4, p. 227-242. Kodosky, L.G., and Keskinen, Mary, 1990, Fuma- role distribution, morphology, and encrustation mineralogy associated with the 1986 eruptive deposits of Mount St. Augustine, Alaska: Bulle- tin of Volcanology, v. 52, no. 3, p. 175-185. Kodosky, L.G., Motyka, R.J., and Symonds, R.B., 1991, Fumarolic emissions from Mount St. Au- gustine, Alaska: 1979-1984 degassing trends, volatile sources, and their possible role in erup- tive style: Bulletin of Volcanology, v. 53, no. 5, p. 381-394. Lawver, L.A., Lachenbruch, A.H., and Moses, T.H., Jr., 1979, Status of regional heat-flow studies in Alaska, in Johnson, K. M., and Williams, J. R., eds., U.S. Geological Survey in Alaska: Accomplishments during 1978: U. S. Geological Survey Circular 804-B, p. B5-B7. Liss, S.A., Motyka, R.J., and Nye, C.J., 1988, Alaska geothermal bibliography: Alaska Division of Geological & Geophysical Surveys, Report of Investigations 88-18, 44 p. Luedke, R.G., and Smith, R.L., 1986, Map showing distribution, composition, and age of late Cenozoic volcanic centers in Alaska: U.S. Geological Survey Miscellaneous Investigations Map I-1091-F, 3 pls., scale 1:1,000,000. Lyle, W.M., 1973, Geology and mineral evaluation of the Aniakchak River drainage, Alaska Peninsula: Fairbanks, Alaska Division of Geological & Geophysical Surveys Open-File Report 26, 11 p. Maddren, A.G., 1919, Sulphur on Unalaska and Akun Islands and near Stepovak Bay, Alaska: U.S. Geological Survey Bulletin 692-E, p. 283-298. Mariner, R.H., Brook, C.A., Swanson, J.R., and Mabey, D.R., 1978, Selected data for hydrother- mal convection systems in the United States with reservoir temperatures greater than or equal to 90° C: U.S. Geological Survey Open-file Report 78-858, 475 p. Markle, D.R., 1979, Geothermal energy in Alaska: Site data base and development status: Anchor- Geothermal Resources of the Aleutian Arc 15 age, Alaska Division of Minerals & Energy Management report to U.S. Department of En- ergy, DE-ACO3-79SF1049, 2 v., 545 p. Marsh, B.D., 1990, Buldir, Gareloi, Moffett, Adagdak, Atka, and Amak, Volcanoes, in Wood, C.A., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cambridge Univer- sity Press, p. 18, 22-23, 25-26, 29-31, 51. McKenzie, W.F., and Truesdell, A.H., 1977, Geothermal reservoir temperatures estimated from the oxygen isotope compositions of dissolved sulfate and water from hot springs and shallow drill holes: Geothermics, v. 5, nos. 1-4, p. 51-62. Miller, T.P., 1973, Distribution and chemical analyses of thermal springs in Alaska: U.S. Geological Survey Open-file Map 570, scale 1:2,500,000. 1990, Fisher, Dutton, Emmons, Hague, Pavlov, Pavlov Sister, Black Peak, Aniakchak, Ugashik, Peulik, and Iliamna volcanoes, in Wood, C.A., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cambridge University Press, p. 46-48, 51-54, 58-60, 63-64, 80-81. Miller, T.P., and Davies, J.N., 1991, The 1989-1990 eruption of Redoubt Volcano: Chronology, char- acter and effects [abs.], in Casadeval, T.J., ed., First international symposium on volcanic ash and aviation safety, Seattle, Wash., 1991, Pro- grams and abstracts: U.S. Geological Survey Circular 1065, p. 33. Miller, T.P., and Smith, R.L., 1987, Late Quatern- ary caldera-forming eruptions in the eastern Aleutian arc, Alaska: Geology, v. 15, no. 5, p. 434-438. Motyka, R.J., 1977, Katmai caldera: glacier growth, lake rise, and geothermal activity, in Short Notes on Alaskan Geology, 1977: Fairbanks, Alaska Division of Geological & Geophysical Surveys Geologic Report 55, p. 17-22. 1978, Surveillance of Katmai caldera and Crater Lake, Alaska, 1977: Fairbanks, Uni- versity of Alaska Geophysical Institute report to U.S. Park Service, contract P.O. PX9100-7-1009, 19 p. 1983, High-temperature hydrothermal resources in the Aleutian arc, in Alaska Geological Society Symposium on western Alaska geology and resource potential: Anchorage, 1982, Proceedings, Journal of Alaska Geological Society, v. 3, p. 87-99. Motyka, R.J., Moorman, M.A., and Liss, S.A., 1981, Assessment of thermal spring sites, Aleutian arc, Atka Island to Becharof Lake-preliminary results and evaluation: Fairbanks, Alaska Division of Geological & Geophysical Surveys Open-file Report 144, 173 p. 1983, Geothermal resources of Alaska: Washington, D.C., Geophysical Data Center, Na- tional Oceanic and Atmospheric Administration, 1 pl. scale 1:2,500,000. Motyka, R.J., Moorman, M.A., and Poreda, RJ., 1983, Progress report - thermal fluid investiga- tions of the Makushin geothermal area: Alaska Division of Geological & Geophysical Surveys Report of Investigations 83-15, 48 p. Motyka, R.J., and Nye, C.J., eds., 1988, A geologi- cal, geochemical, and geophysical survey of the geothermal resources at Hot Springs Bay val- ley, Akutan Island, Alaska: Fairbanks, Alaska Division of Geological & Geophysical Surveys, Report of Investigations 88-3, 115 p., 2 sheets, scale 1:20,000 and 1:4,000. Motyka, R.J., and Nye, C.J., 1993, Thermal water and fumarole gas chemistry, Crater Peak, Mt. Spurr, Alaska: Fairbanks, in Alaska Division of Geological & Geophysical Surveys Short Notes on Alaskan Geology, Special Report 113, p. 31-40. Motyka, R.J., Nye, C.J., Turner, D.L., and Liss, S.A., 1993, The Geyser Bight Geothermal area, Umnak Island, Alaska: Geothermics, v. 22, no. 4, p. 301-327. Motyka, R.J., Queen, L.D., Janik, C.J., Sheppard, D.S., Poreda, R.J., and Liss, $.A., 1988, Fluid geochemistry and fluid-mineral equilibria in test wells and thermal-gradient holes at the Makushin geothermal area, Unalaska Island, Alaska: Fairbanks, Alaska Division of Geologi- cal & Geophysical Surveys Report of Investi- gations 88-14, 90 p. Moffler, L.J.P., ed., 1979, Assessment of geothermal resources of the United States-1978: U.S. Geo- logical Survey Circular 790, 163 p. Myers, J.D., 1990, Seguam, Amukta, Chagulak, Herbert, Carlisle, Cleveland, Chuginadak, Uliaga, and Kagamil Volcanoes, in Wood, C.A.., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cambridge University Press, p. 31-37. Newhall, C.G., and Dzurisin, Daniel, 1988, Historical unrest at large calderas of the world: U.S. Geological Survey Bulletin 1855, 2 v., 1108 p. 16 Professional Report 114 Nye, C.J., 1990, Vsevidof, Recheschnoi, Okmok, Makushin, Gilbert, Spurr, Wrangell, Teller, Espenberg, Imuruk, Koyuk-Buckland volcanic centers, in Wood, C.A., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cam- bridge University Press, p. 37-40, 41-43, 44, 83-84, 88-89, 105-108. Nye, C.J., Motyka, R.J., Turner, D.L., and Liss, S.A., 1992, Geology and geochemistry of the Geyser Bight geothermal area, Umnak Island, Aleutian Islands, Alaska: Fairbanks, Alaska Division of Geological & Geophysical Surveys, Report of Investigations 92-1, 85 p., 2 sheets, scale 1:24,000. Nye, C.J., Queen, L.D., and Motyka, R.J., 1984, Geologic map of the Makushin geothermal area, Unalaska Island, Alaska: Fairbanks, Alaska Di- vision of Geological & Geophysical Surveys Report of Investigations 84-3, 1 pl., scale 1:24,000. Nye, C.J., and Turner, D.L., 1990, Petrology, geochemistry, and age of the Spurr volcanic complex, eastern Aleutian arc: Bulletin of Volcanology, v. 52, no. 3, p. 205-226. Poreda, R.J., and Craig, Harmon, 1989, Helium isotope ratios in circum-Pacific volcanic arcs: Nature, v. 338, p. 473-478. Queen, L.D., 1989, Alteration, fluid inclusion, and water-rock equilibrium in the Makushin hydro- thermal system, Unalaska Island, Alaska: Fairbanks, University of Alaska M.S. thesis, 128 p. Reed, M.H., and Symonds, R.B., in press, Calculation of multi-component chemical equilibria in gas- solid-liquid systems, pt. I: Calculation methods: American Journal of Science. Reeder, J.W., 1981, Initial assessment of hydrother- mal resources of the Summer Bay region on Unalaska Island, Alaska: Geothermal Resources Council Transactions, v. 5, p. 123-126. ____1982a, Hydrothermal resources of the northern part of Unalaska Island, Alaska: Alaska Division of Geological & Geophysical Surveys Open-file Report 163, 17 p. 1982b, Hydrothermal resources of the Makushin Volcano region of Unalaska Island, Alaska: in Watson, S.T., ed., Conference on Circum-Pacific Energy and Mineral Re- sources, 3rd, Honolulu, 1982, Transactions, p.441-450. Republic Geothermal, Inc., 1983, The Unalaska geothermal exploration project, phase 1B: Final report toAlaska Power Authority, 160 p., 16 app., 9 pls., scale 1:24,000 and 1:50,000. 1984, The Unalaska geothermal explo- ration project, phase II: Final report to Alaska Power Authority, 104 p., 13 app. 1985, The Unalaska geothermal explo- ration project, phase III.: Final report to Alaska Power Authority, 105 p., 11 app. Riehle, J.R., 1990, Yantarni, Chiginagak, Kialagvik, Hayes, and Edgecumbe Volcanoes, in Wood, C.A., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cambridge Univer- sity Press, p. 60-63, 84-85, 93-93. Sass, J.H., and Monroe, R.J., 1970, Heat flow from deep bore holes on two island arcs: Journal of Geophysical Research, v. 75, no. 23, p. 4378-4395. Scholl, D.W., Valier, T.L., and Stevenson, A.J., 1987, Geological evolution and petroleum geology of the Aleutian ridge, in Scholl, D.W., Grantz, Arthur, and Vedder, J.G., eds., Geology and resource potential of the continental margin of western North America and adjacent ocean basins - Beaufort Sea to Baja California: Houston, Tex., Circum-Pacific Council for Energy and Mineral Resources Earth Science Series, v. 6, p. 123-155. SEAN, 1987, Scientific Event Alert Network Bulle- tin, v. 12, p. 9. Sheppard, D.S., Janik, C.J., Keith, T.E.C., 1992, A comparison of gas chemistry of fumaroles on the 1912 ash flow sheet and on active stratovolcanoes, Katmai National Park, Alaska: Journal of Volcanology and Geothermal Research, v. 53, nos. 1-4, p. 185-197. Simkin, Tom, Siebert, Lee, McClelland, Lindsay, Bridge, David, Newhall, C.G., and Latten, J.H., 1981, Volcanoes of the world: Smithsonian In- stitution, Hutchinson Ross Publishing Company, Stroudsberg, 232 p. Simons, F.S., and Mathewson, D.E., 1955, Geology of Great Sitkin Island, Alaska: U.S. Geological Survey Bulletin 1028-B, p. 21-43. Smith, R.L., and Shaw, H.R., 1975, Igneous-related geothermal systems, in White, D.E., and Williams, D.L., eds., Assessment of geothermal resources of the United States - 1975: U.S. Geological Survey Circular 726, p. 58-84. __________1979, Igneous-related geothermal systems, in Muffler, L.J.P., ed., Assessment of geothermal resources of the United States 1978: U.S. Geological Survey Circular 790, p. 12-17. Geothermal Resources of the Aleutian Arc 17 Smith, W.R., and Baker, A.A., 1924, The Cold Bay- Chignik district, Alaska: U.S. Geological Survey Bulletin 755-D, p. 151-218. Snyder, G.L., 1954, Eruption of Trident Volcano, Katmai National Monument, Alaska, February- June 1953: U.S. Geological Survey Circular 318, p. 318-324. 1959, Geology of Little Sitkin Island, Alaska: U.S. Geological Survey Bulletin 1028-H, p. 169-210. Sorey, M.L., Nathenson, Manuel, and Smith, Christian, 1983, Methods for assessing low- temperature geothermal resources, in Reed, M.J., ed., Assessment of low-temperature geothermal resources of the United States - 1982: U.S. Geological Survey Circular 892, p. 17-29. Spurr, J.E., 1900, A reconnaissance in southwestern Alaska in 1898: U.S. Geological Survey 20th Annual Report, v. 7, p. 43-263. Swanson, S. E., 1990, Akutan, Pogromni, Westdall, Kejulik, Martin, Snowy, Denisom, Steller, Kukak, Devils Desk, Kaguyak, Fourpeaked, and Douglas Volcanoes, in Wood, C.A., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cambridge University Press, p. 43-44, 44-46, 66-67, 73-78. Symonds, R.B., Rose, W.I., Gerlach, T.M., Briggs, P.H., and Harmon, R.S., 1990, Evaluation of gases, condensates, and SO, emissions from Augustine Volcano, Alaska: The degassing of a Cl-rich volcanic system: Bulletin of Volcanol- ogy, v. 52, no. 5, p. 355-374. Truesdell, A.H., and Hulston, J.R., 1980, Isotopic evi- dence on environments of geothermal systems, in Fritz, Peter, and Fontes, J.Ch., eds., Handbook of environmental isotope geochemistry, v. 1: New York, Elsevier, p. 179-226. Turner, D.L., Forbes, R.B., Albanese, M.D., Lockhart, A.B., and Seed, S.M., 1980, Geothermal resources of Alaska: Fairbanks, University of Alaska Geophysical Institute Report UAG-R-279, 19 p., 2 pls, scale 1:2,500,000. Turner, D.L., and Wescott, E.M., 1985, Geothermal energy resource investigations at Mt. Spurr, Alaska: Fairbanks, University of Alaska, Geo- physical Institute Report UAG-R-308, 105 p., 4 sheets, scale 1:63,360; 1:25,000. Waldron, H.H., 1961, Geologic reconnaissance of Frosty Peak Volcano and vicinity, Alaska: U.S. Geological Survey Bulletin 1028-T, p. 677-708. Waring, G.A., 1917, Mineral springs of Alaska: U.S. Geological Survey Water-Supply Paper 418, 114p. Wescott, E.M., Witte, William, Turner, D.L., and Petzinger, Becky, 1988, Geophysical surveys of Hot Springs Bay valley, Akutan Island, Alaska, in Motyka, R.J., and Nye, C.J., eds., A geological, geochemical, and geophysical survey of the geothermal resources at Hot Springs Bay Valley, Akutan Island, Alaska: Fairbanks, Alaska Division of Geological & Geophysical Surveys, Report of Investigations 88-3, p. 39-66, 2 pls., scale 1:20,000 and 1:4,000. White, D.E., and Williams, D.L., 1975, Assessment of geothermal resources of the United States - 1975: U.S. Geological Survey Circular 726, 155 p. Wilson, F.H., 1990, Kupreanof volcano, in Wood, C.A., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cambridge Univer- sity Press, p. 55-56. Wood, C.A., and Kienle, Jurgen, 1990, Volcanoes of North America: New York, Cambridge Univer- sity Press, 354 p. Yount, M.E., 1990, Dana, Veniaminof, and Redoubt Volcanoes, in Wood, C.A., and Kienle, Jurgen, eds., Volcanoes of North America: New York, Cambridge University Press, p. 54-55, 56-58, 81-82. Yount, M.E., Wilson, F.H., and Miller, J.W., 1985, Newly discovered Holocene volcanic vents, Port Moller and Stepovak Bay quadrangles, in Bartsch-Winkler, S., and Reed, K. M., eds., U.S. Geological Survey in Alaska: Accomplishments during 1983: U.S. Geological Survey Circular 945, p. 60-62. Es a - = w+ + P ee Va a 3 eee ee - ° x ee 4 ae _— ny c 8 , rs 2 aia oO 8 3 ae O $ T . a fo 3 um & cis j ae sro aoa es » = oO BElSERS 28 22 FERRO & s ao) ‘ sa 2522-58 rc ESSER REET ESSS = eels eg esseges eset st = - o Ss ees cs 5 2 g 78 eer B52 2580958 5E= o— © \ = | shes ateiedig has eel ES canve =z § P2zeehaees €<538<5¢ x Pied een BS885 . 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Eesessresgucaggetaes 4 3 o Z z 2§a8r2 25e25 bn dE QE OES eeeeees22 3 Ris UR we Sh Ve 2 £r2 c -ao 9% o s2q eo Soo : aSpeea S25525 ple] ae 9, S < 26a wie e ceo es Ges PBaoe 9 fF 8 ore a ae cee eee © a = ig oo fess gic 5 eas @Eogfcsd Sat 2a,82 z a 8 = % Sepals Eseesue Heng Ge BSe co>se soa2s oo = 5 Keos = ca 2ah aw. wf = o> OS <= = = i = Seen ed - oO Se bs abe blise 22 ige88a3 recta lz uyiise = 2 2s & 12 8 Yass Gah 3 os BZESS3S at SeESESEE2E5 SERS: = 6G CE Bo = 8 SS285325 S2essss 7955 5 Peels: 52,8859 22 ;8 o2 S E*¥teas ot 2 pYgge os as a 23x - ¢ 7 roy 328 Eaxssseg Byes seeede gal rSea ras ¢ = p 2s 33 5G = Leseer esc § ieee ci 4) - |o =a 28 abetiegitiise’ diate B32 és Spe ssas 23eo sr SEB Ee ao E e SSESaeLSRE eS Da eo fw wo 3a ea SESBEL no £3 ors Ss8ESoq Ke ag aaris oe 22 a 22 _ ae as cc % go a moO Ee \ 85 23 ase oO = 8 oo £a i= o§ 23 wo g Be In e.s oa 2 E2% gas g<8 o 8s Ea? ges of ons 622 61°} 60° |~ 59° 58° 57° 56° F 55° | ALASKA DIVISION OF GEOLOGICAL & PROFESSIONAL REPORT 114 GEOPHYSICAL SURVEYS Motyka and others 1993, sheet 4 of 4 Table 1. Locations of geothermal sites in the Aleutian arc, from west to east. Thermal manifestations listed in orde Table 2. Quaternary volcanoes of the Aleuti js of importance H : spuapdihchad 2 fea f geese Table 3. Water chemistry, isotopic analyses, and geothermometry of thermal waters in the Aleutian arc. Waters collected and analyzed by DGGS unless otherwise noted : feet . b Isotope analyses . Location® Eruptive histo: Eruptive products : ; : a eri : : P ry Water chemistry (per mil, SMOW) Seon ec? _ Site names N WwW Type of activity’ : : i i i ivi iti Mi Geothi 1 Fa Volcano Latitude Longitude Elevation Current Most recent activity Compositional lost eo! ermal 18 ‘ : yi hanes ra a in) morphology’ Date Type ange recent potential’ HCO; 5 80 5D Quartz Na-K Na-K-Ca Mgcorr K-Mg Mg-Li Na-Li H,0-SO, } | | | } | Map Date Temp. no. Site name sampled °C pH Li Sr Little Sitkin 51°57'55" 178°28'50"P F, HS? ie ae 31303 Teh MS 2 Buldir 52°21'00" _175°54'38"° 656 Strato-P eee : ey PAO 00 SE East Cape 52°21'54" —-175°56'24"° 610 Strato-P Kipues Warm Spunes eee sors psc Kiska 52°06'10" —-177°36'07" 1,220 Strato pried Hot Springs 51 aoe 17073200; HSc : Segula 52°00'55" 178°08'08"" 1,160 Strato a oa ae Leos 40 Fe HSs:ME Little Sitkin 51°5700" 178°32'35"° «822; 1,174 Strato w/cald-A-5S ae oa Ve a0 F, HSac/HSs, MP Semisopochnoi 51°5723" 179°37'50"* 180; 850 Shield wicald-A-7S-P Pani rae LOE p> HBac Gareloi 5194725" 178°47'38" 1,573 Composite-P meet Bae Ue a. Sajaka 5195232" 178°11°36" 1,304 Strato neon Rss 0i0 pect ee Mr Tanaga 51°53'06" —_-178°08'45" 1,768 Composite Kagami 52°59'00" 169°42'00" F, HS iO Tekeyanshe Piece eae ee Stn any ee farce : | vil Bobrof 51°54'36" —177°26'18" 738 Strato ee na) ee He, Ge, SE, HSac 51°55'22" 17791004" 1,253; 1 Strato w/eald-C Hot Springs Cove 53°14'41" 168°21'39" HSc Vi2 Kanaga 25331, ato wical eee Rites ee ne V13 Moffett 51°56'38" 1,196 Strato-4P ln Sasi eae 3 V4 Adagdak 51°59'1 610 Strato-P eae as peau eet Z V15 Great Sitkin 52°04'34" 1,280; 1,750 Strato wicald-A-6P Towa Glacier Valley Pais eae eek V16 _Kasatochi 52°1039" 17°30 314 Strato Upper Glacier Valley 53°50'48" 166°53'00" SF, HSs Se onIE Peale Omens pel Salo Seater eine oo > VI8 Korovin 52°22'52" 17490915" 1,533 Strato-C-P in Valley 53°53'27 166°50'09 WLe, F, HSs, HSac, MP Cee rae See SommerBay aac nese aes V9 Kluichef 52°19'54" —174°08'12" 1,451 trato-C- | Akutan Fumaroles 54°08'40" 165°54'28" F, HSac 20 Konia §2921'37 174°07'45 1,125 Strato-C V21 Sarichef 52°20'52" 1740248" 610 Strato-C Hot Springs Bay 54°08'55" 164°51'43" HSe Akun Strait 54°08'24" 165°38'24" WSe 22 Seguam (Pyre Peak) 9 52°18'55" 172°30'35" 1,054 Strato-C-A-3P | Pogromni 54°40'00" 164°42'00" HS? 23 Sequam East 52°20'00" 172°21'35" 854 Strato-C-A-3P Mount Finch 54°40'00" 164°22'00" F, CLac V24 = Amukta §2°30'00" 171°15'08" 1,067 Strato V25 Chagulak 52°34'36" 171°08'00" 1,142 Strato Shishaldin 54°45'20" 163°58'15" F cevtee iit t | False Pass 54°55'49" 163°14'24" HSc v26 Yunaska 5293834" 170°3743" 610 Strato w/eald-C-A-9P Kenmore 163 WS V27 Herbert 52°44°32" —-170°06'38 1,280 Strato w/cald Egg Island HSc V28 = Carlisle §2°53'38" 170°03'15" 1,620 Strato | Cold Bay HSc v29 Cleveland 52°49'30" 169°56'3 1,730 Strato Emmons Lake 55°20'00' HSh V30 —_Uliaga 53°03'54" 169°46'0 888 Strato Hague §5°22'05 161°57'3 F V31 + Chuginadak East 52°50'26" 169°45'3 1,170 Strato Pavlov §5°25'20 161°53'3 F | V32 Kagamil 52°58'25" 893 Strato Port Moller 55°51'42 160°29'30" V33 ~~ Vsevidof 53°07'48" 2,134 Strato-P Kupreanof 55°59'07 159°51'33 F 34 ~—- Recheshnoi 53°09'24" 168°32'20 1,984 Strato-2P Aniakchak 56°56'03" 158°07'10' V35 Okmok 53°24'20" 168°10'4: 670; 1,072 Shield w/cald-A-7S-P Mother Goose 57°10'48 157°01'06' oh V36 ~~ =Bogoslof 53°55'46" 168°0O1'4: AA Dome complex 1992 Dome Chiginagak §7°09'00 156°58'48" V37~—- Pakushin Cone 53°49'42" 166°58'42 1,035 Strato Holocene ? : Ukinrek 57°50'00 156°30'35" V38 = Makushin 53°53'2T" 166°55'2 2,036 Shield w/cald-A-S 1987 Explosive Gas Rocks 57°51'16 156°29'3 39 Table Top Mountain —53°58'05" 166°40'3: 792 Strato Holocene 2 Mount Martin 58°10'10 155°21'1 V40 Wide Bay Cone 53°57'43" 166°36'46" 610 Strato Holocene Mount Magick 58°11"41" 155°15'1 V41 Akutan 54°08'04" 165°59'10" 1,303 Strato w/cald-A-S 1992 Explosive Novarupta 58°16'00" 155°09'2 V42_— Gilbert 54°15'10" 165°39'35" 818 Strato Pleistocene 7? | Magiek Creek 58°11'40" 155°08'3 W: a V43— Pogromni 54°34'24" 164°41'48" 2,002 Strato-S-P 1830 Explosive Mount Trident §8°13'45" 155°06'S F : V44 = Westdahl 54°31'06" 164°39'00" 1,560 Shield-S-P 1992 Effusive Mount Griggs 58°20'45" 155°06'2 SF V45_—‘ Fisher 54°40'44" 164°28'52" 1,094 Strato w/cald-A-S 1826 Ash : Katmai Crater Lake 58°15'50" 154°58'30" V46 ~~ Shishaldin 54°45'20" 163°58'00" 2,856 Strato-25P 1993 Ash, steam Snowy Mountain §8°20'10" 154°40'10" SG : V47 ~~ Isanotski 54°45'54" 163°43'21" 2,446 Strato 1845 Explosive Kukak 58°27'10" 154°21'18" FE ; V48 ~=Roundtop 54°48'00" 163°35'20" 1,871 Strato Holocene Mount Douglas 58°51'24" 153°32'31" v49 = Amak 55°25'26" 163°08'57" 488 Strato 1796 ? Augustine Volcano 59°21'48" 153°26'00" SF V50 Cold Bay 55°04'54" 162°48'50" 2,012 Strato Holocene ? Tliamna 60°01'55" 153°05'25" F V51 =‘ Dutton 162°16'18" 1,474 Dome complex Holocene Block & ash flow Redoubt 60°29'07" 152°41'31" SG : 52 Emmons 55°20'26' 162°04'43" 1,326; 1,436 Strato-C Holocene ? : 55 Mount Spurr 61°17'58" 152°15'04" F, SG V53 ~~ Hague 55°22'04" 161°59'30" 1,341 Strato-C-P 1990 Steam | Crater Peak 61°15'56" 152°14'19" F, CLac, WSh 54 ~~ Double Crater 55°22'24" 161°58'20" 1,463 Strato-C Holocene ? — V55_—-Pavilof 55°25'00" 161°53'15" 2,519 Strato-C-S 1988 Explosive ‘Abbreviations: V56 —Pavlof Sister 55°27'10" —-161°50'35" 2,143 Strato 1786 Explosive ac - acid spring, ph <5.5. MP.- mud pot. V57 Dana 55°38'28" —:161°12'50" 1,280 Dome complex 3480 BP Block & ash flow c¢- chloride anion dominant. s - sulfate anion dominant. V58 Kupreanof 56°00'40" 159°47'50" 1,890 Strato-5S 1987 Explosive CcCL-C 5 SF - rhe le. A = Cie eee 59 Veniaminof 56°11'44" 159°23'18" 2,155; 2,500 Strato w/cald-A-S-P 1993 Explosive, effusive G- geyser. WL - geothermal well. V60 Black Peak 56°33'09" 158°47'05" 1,032 Strato w/cald-A Holocene Dome 1931 Explosive, Dome? GV - gas vent, boiling point. WS - warm spring, T <30°C. | V61 Aniakchak 56°52'55" 158°09'08" 1,020; 1,341 Strato w/cald-A h - bicarbonate anion dominant. ? - activity questioned where unconfirmed. V62 Yantarni 57°01'07" 157°11'06" 1,345 Strato-2P Holocene 9 HS - hot springs, T >50°C. 63 Chiginagak 57°08'06" —-156°59"24” 2,221 Strato-P 1972 Explosive Sites 1 and 2 ate east longitude: vo4— Kialagvik 57°12'10" —-156°44'43" 1,677 Strato Holocene? V65 —- Ukinrek 57°49'54" 156°30'35" 16 Maar 1977 Explosive V66 ~~ Ugashik 57°43'43" 156°22'10" 840; 921 Strato w/cald-A-S Pleistocene ? V67_~—~Peulik 57°45'03" 156°22'05" 1,471 Strato-C-S 1852 Explosive V68 = Kejulik 58°03'14" 155°40'08" 1,585 Strato Pleistocene 7? V69 = Martin 58°10'20" 155°21'40 1,863 Strato 1953 Explosive V70. = -Mageik 58°11'41" 155°15'10' 2,165 Strato 1946? Explosive? V71~— «Cerberus 58°14'47" 155°11'56 1,098 Dome Holocene ? V72_~—«*Failling Mountain 58°15'20" 155°10'19' 1,160 Dome Holocene 7 V73 ~~“ Novarupta 58°16'00" 155°09'24 841 Dome 1912 Ashflow = / : f V74_— Trident 58°14'08" = 155°06'00' 1,864 Strato-cluster 1968 Explosive = : \ : V75 Griggs 58°21'14" _ 155°05'30" 2,317 Strato Holocene? i | V76 Katmai 58°16'47" 154°57'48" 2,047 Strato cluster w/cald-A 1912-1916 Dome V77_~—«- Snowy Mountain 58°20'08" 154°40'55" 2,162 Strato Holocene 2 V78 ~~ Dennison 58°25'04" 154°26'57" 2,287 Strato Holocene? V79— Kukak 58°27'10" 154°21'18" 2,043 Strato Pleistocene V80 Devils Desk 58°28'28" 154°18'20" 1,955 Strato Pleistocene V81 Kaguyak Crater 58°36'30" 154°01'40" 901 Strato w/cald-S Holocene V82 = -Fourpeaked 58°46'12" 153°40'20" 2,105 Strato Pleistocene V83 = Douglas 58°51'19" 153°32'31" 2,135 Strato Holocene V84 = Augustine 59°21'48" 153°26'00" 1,282 Strato, Dome complex 1986 Dome, nuee | : V85 ~~ Iliamna 60°01'55" 153°05'25" 3,054 Strato-5S 14 1987 Steam f V86 Redoubt 60°29'07" 152°44'31" 3,109 Strato 1990 Dome, nuee, lahar V87~—s Spurr 61°17'58" 152°15'04 3,374 Strato Holocene Explosive x V88 ~~ Crater Peak 61°16'10" 152°14'15" 2,309 Strato-C 1992 Explosive, lahar E| v89 = Hayes 61°38'25" 152°24'41" 3,034 Strato 3500 B.P. Explosive Chloride waters 2 4 Kiguga Warm Springs® 7-81 20 7.0 5 86. 94 87 43 56 - - 5 Andrew Bay Hot Springs 7-21-81 57 6.0 : 12,000 : 118 186 13a Geyser Bight - G8 4 7-10-88 100 15 K 62 657 f NC 225 249 13b Geyser Bight - H6 7-16-88 104 19 . 32 556 : : ‘ 164 : NC 215 248 13c Geyser Bight - J1 7-24-88 80 8.2 52 589 : i : 200 NC 220 242 14 Hot Springs Cove - E1 7-29-80 94 6.5 1,260 ; ; A NC 160 143 15 Partov Cove 7-31-80 84 6.6 1,100 : . 144 NC 150 219 20. Makushin Valley, Well ST-1° 8-07-84 16 12 3,500 ‘ NC 261 193 21a Summer Bay - Well 1 9-26-80 50 - . - 923 / . A 60 NC Al 8 Summer Bay 8-07-80 35 7.0 . B 404 86 NC 57 42 23 Hot Springs Bay - A3 8-07-80 84 7.0 424 : y . NC 123 168 | 24 ~~ Akun Strait 8-10-80 43 15 : 82 3,400 . 62 6 ) 28 ‘False Pass 7-02-80 62 8.4 . 45 53 . NC 89 102 29 Kenmore 7-03-80 43 74 3 ‘ 1,600 : . NC 38 17 | 30‘ Egg Island 8-21-80 51 17 i 67 4,500 p : t NC 97 36 | 31 Cold Bay-L 7-06-80 54 6.7 : 1,370 . : i . NC 89 35 Port Moller 8-18-80 71 8.2 . 71 1,600 3 , r NC 37 40 Ukinrek 8-24-80 16 9.0 : ; 199 210 n - 41 Gas Rocks 8-17-81 39 5.7 72 26,100 . 54 ? hbA pxA > Pleistocene ? Pleistocene Dome 1990 Explosive Holocene 2 1900 Explosive 1987 Explosive 1987 Effusive 2 1 1914 Explosive Holocene 2 ? Z 1994 Explosive Pleistocene ? Pleistocene 7? 1975 Dome, effusive 1828 Dome ? ? 1987 Explosive 1812 ? . some px A,D Historic? ? , some px A, D 1812? ? B, some px A, D 1993 Lava flow B, A, D, RD 2 2 B, A, D, RD 1987 Explosive A? Holocene 2 1937 Explosive Holocene ? 1987 Explosive 1987 Effusive Holocene 2 ? 2 1929 Explosive 1957 Explosive 3000 BP Effusive 1988 Explosive x tg o _ WaornunbhwvN = COm>ROUSCNSSH OHNSHFOONCOCHRORNUWOASCS >>> PE > >E vuouDY DUO SES OR > >> e > ib A, hb D > BE > , some px A,D Damme row Mixed and peripheral waters 18 LowerGlacier Valley-Gp . 7-20-82 40 - 63 380 . . 65 32 Emmons Lake f 8-21-80 65 6.2 Y . 100 : NC 37 Aniakchak - Surprise Lake 725-516 ~~ 23 5.7 ; 86 . 33 38 Mother Goose 8-23-80 66 6.4 528 ! . . 24 44. -VTTS- Mid-Valley Spring 2® 6-04-90 29 59 f 90 : NC 45 Mageik Creek 2° 8-03-82 42 6.8 279 3 23 56b Crater Peak Warm Spring 8-03-85 40 254 k : 17 oe > ne) Steam-neated waters Great Sitkin 7-22-81 79 ‘ 10 0.1 Korovin - A 7-15-80 99 4 5.0 02 Kluichef - Al 7-14-80 94 : E 5.0 0.0 Milky River 7-29-81 45 . $3) 11 Upper Glacier Valley - Gf 7-05-81 79 : . IS 02 Makushin Valley - Mb 8-13-80 87 : 5.0 01 Akutan Fumaroles 7-09-81 92 F lO : : } “ N so eur OU F>p> 5 a WDrrvvyw vw Eee. pep a = DOMMVUAVVIUVAMAMVOMNVIAHOVIAAVAAMAANONDVY Q p> Acid “volcanic” waters h 48 Katmai Crater Lake 7-08-75 6-20 ere 140 300 62 590 1,200 1,750 51 Mount Douglas Crater Lake! 7-20-91 21 12 Ai7 33 TA 8.6 E 1,230 2,070 56a Crater Peak Crater Lake’ 1972 - 22 - 182-70 a5 315 1,100 - a Optwrporrryr yyy yyy 2 > 9 -- = no data. per mil with respect to standard mean ocean water (SMOW). DGGS samples analyzed at Southern Methodist University, Dallas, Texas. Geothermometers: Quartz -- Fournier and Potter (1982). Adiabatic geothermometer used for boiling springs. Chalcedony -- Founier and Potter (1982). Adiabatic geothermometer used for boiling springs. Na-K -- Fournier (1981). Fournier's equation used. Na-K-Ca -- Fournier (1981). | Mg Correction to Na-K-Ca -- Fournier (1981); Fournier and Potter (1979). NC - no correction. | K-Mg -- Giggenbach (1988). Mg-Li —- Kharaka and Mariner (1989). Na-Li -- Fouillac and Michard (1981). 8 180, H,O-SO, -- McKenzie and Truesdell (1977). a atzenstein and Whelan (1985). Collected by DGGS. Analyzed by DGGS and University of Utah Research Institute (Salt Lake City, Utah). Analysis of water collected from Weber-separator at well-head (Motyka and others, 1988). Ivan Barnes, U.S. Geological Survey, written commun. (Menlo Park, California). 8vrts = Valley of Ten Thousand Smokes; Keith and others (1992). Botyka (1977). ‘Miller (1973), ANWhROWDS www w~ noo wo Pw ~ poo - pP> OU ~ ~ or OoWn 2 C., DOW > Opry oF 2 p > Onomwowoew or Horr ocooce ~DOWWO~> 0 3 Table 4. Chemistry and geothermometry of gases emitted from geothermal fumarole fields and chloride thermal spring systems in the Aleutain arc b. Gas chemistry” ‘ Geothermometry (°C) Dry composition (mole %) Map Temp. H,O CO; Has. no. Site names °C — (mole %) + CO, HS" Hp CH, NH, No 02 Ar Hy-CH, —-HofAr® ~— CO/Ar® 7 Fumarole fields ’ Table 8. Additional sites suspected of having hydrothermal systems 6 Great Sitkin 98 11 0.37 0.64 = <0.01 696 = 17.4 0.82 NA 167 129 7 Korovin 97 65.1 2.65 0.26 0.11 29.1 2.21 0.58 151 184 Reservoir temperatures unknown, probably >150°C. 8 Kluichef 96 58.7 6.14 4.18 0.07 278 2.51 0.56 236 183 9 Milky River 96 9 = 15.2 7.36 0.03 523 0.07 0.10 306 227 Map Land Makushin Volcano - ff5 98 39.9 0.93 0.51 0.0039 825 0.28 0.065 244 246 Shenae eae Resear 17c Makushin Volcano - ff? 97 81.2 1.79 1.09 2.45 13.0 0.24 0.085 256 236 19a Upper Glacier Valley - £f3 88.0 6.37 0.95 0.0096 448 0.013 0.056 261 244 eee Upper Glacier Valley -£¥4 98 919 O81 120 <O01 6.12 0.18 0.06 20 ~=—«-246 Tittle Sitkin NWR, W 19¢ Upper Glacier Valley - ff9 99 914 3.94 0.85 0.0041 3.72 0.024 0.026 282 262 Makushin Valley - ffl 98 81.8 2.27 0.21 0.039 15.1 0.11 0.18 182 218 Seguam NWR, W ? Novarupta Makushin Valley - {£2 93 90.2 2.92 0.35 0.012 638 0.042 0.073 224 239 : Kagamil | NWR, W Mount Trident 22 Akutan Fumaroles 99 94.4 1.41 0.19 0.91 i 3.07 0.048 ~— 0.021 246 269 Geyser Bight SF N, AK Mount Griggs 22. Akutan Fumaroles 87 92.5 2.83 0.34 1.32 2.96 <0.01 0.02 261 267 16 Okmok Caldera N Katmai Crater Lake 17a Makushin Voleano Summit N Snowy Mountain Chloride thermal spring systems : ' 26 = Mount Finch NWR, W Kukak 5 Andrew Bay Hot Springs 57, 95.1 - <0.01 0.13 359) 1.10 0.04 25 27 ~~ Shishaldin NWR, W Mount Douglas 13a Geyser Bight 97 13.5, <0.0) 0.09 0.04 85.3 0.70 0.78 100 33 Hague NWR Augustine Volcano 13a Geyser Bight 98 412 ~ 0.03 <0.01 54.0 43.9 0.64 62 34 Pavlov NWR Tliamna 18 Lower Glacier Valley 44 98.2 <0.02 <0.005 0.052 0.96 0.31 0.02 <50 36 Kupreanof NWR Redoubt 23 Hot Springs Bay 85 10.3 6.26 0.45 4,58 76.7 <0.01 L73: 12 / 37 Aniakchak NMP Mount Spurr 31 Cold Bay 54 285 <0.01 0.10 66.04 27.1 6.038 2,000 : 38 Mother Goose BLM, N Chater Peak 32 Emmons Lake 65 474 <0.01 0.01 4.36 47.6 20.2 0.66 100 39 Chiginagak NWR Latitude, longitude, and elevation are given for the highest point on the volcano, except for those volcanoes with calderas. If there is an active eruptive center within the caldera, the latitude, longitude, elevation listed are 35 Port Moller al 0.02 <0.0 10.01 87.89 11.6 0.02 0.25 100 for the eruptive center.When the elevation of the eruptive center is lower than the elevation of the caldera rim, the maximum elevation of the rim is the second listed value. When there is no active eruptive center, the 41 Gas Rocks 39 99. gof iat 0.0002 0.00045 0.0114 0.0026 0.00026 1 . position given is for the center of the caldera, and listed elevation is for the highest point on the rim. : i ‘ . S : . / Reservoir temperatures unknown, probably < 150°C. : : Rock codes are B - basalt, BA - basaltic andesite, A - andesite, D - dacite, RD - rhyodacite, and R - rhyolite. Mineralogical modifiers are hb - hornblende and px - pyroxene. lees ee ROT eT =| oe “Letters used after the primary morphologic designation have the following meanings: “Gas analyser Ee GPE ueEES: Map Land a Syste: Map Land | : : fF Site name status type no. Site name status” - indi ivity within a summit 1. ater. i ase ce pea pe seas of an older caldera : NaOH: sodium hydroxide-charged evacuated flasks; analyzed by R.J. Motyka (DGGS), C.J. Janik (U.S. Geological Survey, Menlo Park, California), M.A. Moorman (DGGS), and S.A. Liss (DGGS). i 2 He: helium impermeable 1720 Corning glass evacuated flask, analyzed by J.A. Welhan and R.J, Poreda (Scripps Institution of Oceanography, LaJolla, California), and R.J. Motyka (DGGS). TIVO UV U NVM INV UU IN UN VU VU VU UUN aN : wn rPUOUUYY YP PMY er oOY wn “ a s 3 ~ an ot wp TU a 3 Mount Martin Kanaga NWR, W Mount Mageik o vUN Uy UU wecocoocoonouwnrosd : bef 4 uP oO a UPUPY ER YOM ENO a U> PRD >>> p> U wom Tt ohon w<<<<<<<<<<c<<< <a<<<<<<<<20 “fA 33 o_o oA - indi s the LI 8 t ur on the flanks of calderas, stratovolcanoes, or shield volcanoes. Ce ee Pe et et ateanlien Goctt on ihe Haas of calc SATORU Clear Reg: uncharged evacuated flasks; analyzed by W.C. Evans (U.S, Geological Survey) and R.J, Motyka (DGGS) : 2 Semisopochnoi NWR, W 40 Ukinrek N Vv - oe “wills 6 Gr © gives Un waeaivesiof oavnlite volcanoes, cones, or vents. Sometimes this value is a minimum. b NaOH+He: Mole % CO, and sulfur gases determined from NaOH sample by RJ. Motyka (DGGS). Ratio of CO + sulfur gases to total dry gases and all other constituents determined from He flask by J.A. Welhan (Scripps Institution of Oceanography, Lajolla, ‘ iM Chuginadak NWR, W 44 —_ Novarupta - Mid-Valley Springs NPP, W V,G ‘Abbreviations: F = fumaroles; SF = super heated fumaroles; HS = thermal spring, T > 50°C; WS = thermal spring, T < 50°C; lower case letters, c = chloride, h = bicarbonate, ac = acid spring. : 18 Lower Glacier Valley N 45 Mageik Creek NPP, W V,G Geothermal potential indicates estimated potential for presence of developable hydrothermal system. a C - Confirmed: a hydrothermal system with temperatures suitable for power generation has been confirmed by direct observation or by drilling. “Total mole % sulfur gases collected in NaOH charged flasks are reported as H2$ which is the stable equilibrium sulfur gas phase in most hydrothermal systems. ; : 25 Pogromni NWR, W {by Amore and Panichi (1980). G - Good: abundant thermal springs and/or fumarolic activity. ee F - Fair: some thermal springs and/or fumarolic activity or Holocene activity with geologic evidence of a shallow magmatic system. pCigeenbach and Goguel (1989). Land status: AK = State of Alaska; BLM = Bureau of Land Management; N = Native lands; NMP = National Monument and Preserve; P - Poor: no surficial thermal manifestations or geologic evidence of a shallow magmatic system. Reported as COz + HaS. pNPP = National Park and Preserve; NWR = National Wildlife Refuge; W = Wilderness. Map numbers V1-V6 are east longitude. EReported as Op + Ar. ‘Type of system: G = geothermal; V = volcanic vent. i Sees =| 5 ene eee = jaan | | | Table 5. Chemistry of gases emitted from fumaroles associated with volcanic vents in the Aleutain arc 1 Table 6. Isotopic analyses of gases emitted from geothermal fumarole fields, thermal springs, and fumaroles associated with volcanic vents in the Aleutian arc Table 7. Estimates of reservoir temperatures, volumes, and energy stored in identified hydrothermal systems Gas chemistry” Isotope analysis | Dry gas composition (mole %) 5p! Reservoir" Wellhead” | Map Gas Sample Date Temp. H,0 ste Ns@ Map Date 3He/*He Electrical | ‘ b is ‘ P | 5 Site name source type sampled C (mole %) CO, (orSO) (or HS) Hp HCl HF CH, No 0, Ar no. Site names Gas source” sampled R/Ra? Hy ___ Estimated temperature (°C) Estimated Thermal Thermal Available energy Beneficial | ; Map Most volume energy energy work (MWe for heat | 16 Okmok Caldera Cone -F NaOH+He 7-14-81 97 - 57.0 0.09 = 0.20 <0.01 35.8 6.55 0.42 Geothermal fumarole fields | no. Site name Min Max likely Mean ___(km*) __—0* J) ao’ }) (10'* J) 30 yr) doy) a | 17a Makushin Volcano CraterRim-F NaOH 7-18-82 96 9833 87.5 55300 = 0.21 0.047 6.57 0,093 - 6 Great Sitkin 7-23-81 68 -384 17a Makushin Volcano CraterRim-F He 714-85 940 89.8 ss (6.3) 0.019 0.019 37 0.04 0.0061 i Korovin 7-31-81 53 -488 >150°C 40 Ukinrek Crater - CL Reg 824-77 BL = TIS oor - <0.01 -~ 1.88 15.1 3.19 0.34 Kluichef 7-29-81 3.8 ~ . Andrew Bay Hot Spring 43 Mount Magick CraterRim-SF NaOH 7-10-79 99.15 90.1 43 0.1 2.84 0.66 0.0762 1.81 <0.00001 0.011 Milky River F 7-29-81 63 629 Great Sitkin 44 Novarupta Dome - GV NaOH 6-16-78 47 10.9 - 0.28 RI 153 0.88 ' Makushin Volcano - ff5 F 7-14-85 53 “542 . Korovin 46 Mount Trident® Summit - F NaOH 703-79 97 9959 «360-523 4, 2 . 0.00027 698 0. , Makushin Volcano - £f7 F Eas 8S “987 i unt Triden' urnmi jal 9 >4.0 7 2.3 <0.000: 0.012 0.099 Upper Glacier Valley - £3 SF 7-08-83 45 “582 Kluichef a Mount Griggs Summit 3 SF NaOH 7-02-79 105 99.35 79.6 13.1 21 0.292 5.85 0.042 1.05 0.016 0.010 : : Upper Glacier Valley - ff4 HS 7-14-82 ~ 619 s Milky River ount Douglas Crater Rim - F Reg 8-02-82 94 - 90.3 9.91 <0.05 -- — <0.01 1.76 0.08 - i Upper Glacier Valley - ff9 F 7-11-83 610 ie Geyser Bight 51. Mount Douglas Crater Rim - SF NaOH 7-21-91 114 95.03 23.4 27.2 - 0.016 8.07 <0.001 36.5 44 0.45 Mekathin Valley - fl F 7-17-83 67 “sag ; / ; Hot Springs Cove 51 Mount Douglas Crater Rim - SF Reg 7-21-91 114 - 52.1 (39.7) (<0.001) 0.048 -- <0.0002 10.0 0.0045 0.12 : Makushin Valley - £f2 HSac 7-17-83 54 -587 . 3 Makushin Volcano ff5 52 Augustine Voleano 1976Dome-SF NaOH 7-84 357 99.83 19.5 9.43 - 53.7 13.7 0.094 “2.95 0.1 0.038 | Akutan Fumaroles HSac 7-07-81 T | Makushin Volcano ff7 52 Augustine Volcano, 1976 Dome-SF Reg 7-84 357 - 7.12 (1.4) (<0.01) 62.0 -- <0.01 23.8 TA 0.36 <500 7 Upper Glacier Valley 52. Augustine Volcano 1986 Dome-SF NaOH 8-28-87 870 = - 74.84 14.8 46.4 -- 3.54 34.8 nr - 0.44 0.006 = i | Thermal springs ce Makushin Valley 56 Crater Peak Crater Rim - F NaOH 8-04-82 95 97.89 94.7 0.77 - 0.32 -- 0,034 <0.001 4.09 0.042 0.055 <10 5 Andrew Bay Hot Springs HSc 7-21-81 6.6 - Akutan Fumaroles — | Wa Geyser Bight HSac 7-14-81 TS - : Hot Springs Bay x =not done; nr = not reported; Tr = trace. 18 Lower Glacier Valley WSh 7-16-83 2.8 -14.0 ; | Emmons Lake ‘Analyses of gases collected by DGGS: NaOH = sodium-hydroxide cherged evacuated flasks analyzed by RJ. Motyka (DGGS), C.J. Janik (U.S. Geological Survey, Menlo Park, California), M.A. Moorman (DGGS), and S.A. Liss (DGGS). He = helium impermeable 1720 23 Hot Springs Bay HSe 7-09-81 6.5 -18.1 Corning glass evacuated flask analyzed by A.W.A. Jeffrey (Global Geochemistry Inc., Canoga Park, California), RJ. Poreda (Scripps Institution of Oceanography, LaJolla, California), and RJ. Motyka (DGGS). Reg: uncharged evacuated flasks analyzed by |. 31 Cold Bay HSc 7-06-81 3.9 - W.C. Evans (U.S. Geological Survey, Menlo Park, California) and R.J. Motyka (DGGS). NaOH+He = mole % CO, and sulfur gases determined from NaOH sample by RJ. Motyka (DGGS); ratio of CO, + sulfur gases to total dry gases and all other constituents : 35 Port Moller HSe 8-18-80 2.1 - determined from He flask by J.A. Welhan (Scripps Institution of Oceanography, LaJolla, California). : 41 Gas Rocks HSe. 7-21-81 69 -27.4 ’ Partov Cove N I5le Abbreviations: F = fumaroles; SF = super-heated fumaroles; GV = gas vent below boiling point; CL = crater lake. ee a Cold Bay NWBW Lae: Total mole % sulfur gases collected in NaOH-charged flasks or mole % Sy (for gases collected in uncharged flasks). : : Volcanic vents la Port Moller BLM & AK 124 f Average oxidation state of sulfur in NaOH flasks ( cf. Giggenbach and Goguel, 1989) or mole % H,S (for uncharged flasks). : 16 Okmok Caldera Cone - F 7-14-81 65 -36.8 Gas Rocks N 153 g Reported as Op + Ar. 17a Makushin Volcano Crater rim - F 7-18-82 78 -39.5 eee aoe and McCoy (1979). 17a Makushin Volcano Crater rim - F 7-14-85 8.0 -23.7 poheppard and others (1992). / -| 47 Mount Griggs Summit - SF 6-20-78 det -- - Kiguga Warm Springs 56f Symonds and others (1990). : 51 Mount Douglas Crater rim - F 8-02-82, 8.0 -6.0 -31.4 . ‘a ED Summer Bay 66 f ‘ 51 Mount Douglas Crater rim - SF 7-21-91 FA -6.6 - oe Akun Strait 106 € 52 Augustine Volcano ff1 1976 dome-SF 7-25-84 - -8.6 ad : False Pass 91f 52 Augustine Volcano ff2 1976 dome -SF — 7-25-84 76 42.4 -53.3 7 Kenmore Bd 56 Crater Peak Crater rim - F 8-04-82 6.6 -12.4 -22.5 : ' Egg Island 97 ¢ a= not done. pAbbreviations same as for tables 3 and 4. | = not applicabl RRa: ratio of 3He/*He in sample to 3He/4He in atmosphere corrected for air contamination. Analyses performed by R.J. Poreda (Scripps Institution of Oceanography, La Jolla, California). ape Pp ieanles . . . . . 8 13C in per mil referenced to PDB (Fritz and Fontes, 1980). Analyses performed at U.S, Geological Survey (Menlo Park, California) and Global Geochemistry Inc. (Canoga Park, California). ‘eservoir temperatures, volumes, and stored thermal energy estimated following methods discussed in Mariner and others (1978), Brook and others (1979) and Sorey and others (1983). a. Reservoir temperatures estimated using geothermometry and geothermal well data. ag D and 8 !80 are in per mil referenced to standard mean ocean water (SMOW) (Fritz and Fontes, 1980). Analyses of § D-CH,, 5 D-H,, and 8 !80-CO, performed at U.S. Geological Survey (Menlo : : Park, California) and at Global Geochemistry, Inc. (Canoga Park, California). Analyses of 8 D and 6 !80 of H,0-vapor (fumarole condensates) performed at Southern Methodist University (Dallas, eae b. Estimated volumes for unexplored systems calculated using 1.67 km for mean reservoir thickness (Mariner and others, 1978). Subsurface area represents the largest uncertainty in estimating a Texas), ee reservoir volume. Area estimates are based on surface expressions of the geothermal resource. Where the only evidence of a hot water reservoir is one spring or fumarole or a group of 75/'5N in per mil referenced to standard NBS-14 (Fritz and Fontes, 1980). Analyses of gas samples collected in July 1985 performed at Global Geochemistry, Inc. (Canoga Park, California). L co or fumaroles, the subsurface reservoir volume is assumed to be 3.3 km’ for T > 90°C (Mariner and others, 1978; Brooks and others, 1979) and 1 km’ for T < 90°C (Sorey and others, Steam phase. i . c. Thermal energy stored in the geothermal reservoir calculated from Q, = pe * V * (T - T,,¢), where Q, is reservoir thermal energy in joules; pe is volumetric specific heat of rock plus water b (2.7 vem’ /°C); V is estimated reservoir volume; T is mean reservoir temperature; and Tref is reference temperature, 15°C. Wellhead thermal energy, available work, electrical energy, and beneficial heat calculated using methods described in Brooks and others (1979). a. Wellhead thermal energy computed from Qy., = Ry *Q, where Ry is a recovery factor (assumed at 0.25). b. Available work calculated from W, = R, * Q, where R, is the ratio of available work to reservoir thermal energy (determined from figure 5 in Brooks and others, 1979). cE energy (MWe for 30 yr) computed from E = W,, * N,, where N,, is a utilization factor. The value of 0.4 is assigned to N,, for these calculations based on discussion in Brooks and others (1979). d. Beneficial heat calculated from By, = Qy, * Up, where Uj, is a beneficial heat utilization factor equal to 0.24 (Brooks and others, 1979). qlower-case letters "a" through “I” keyed to tables 3 and 4; w = geothermal well temperature; v = vent temperature. : ee ee hea fe a ie a NAT Roman J. Mota and Mary ctr f Land status: AK = State of Alaska; BLM = Bureau of Land Management; N = Native lands; NWR = National Wildlife Refuge; P = Private land; USN = U.S. Navy; W = Wilderness. i oe “ le i i Ce A 4 : mAeiRe CES PROFESSIONAL REPORT 114 Motyka and others 1993, sheet 2 of 4 ALASKA DIVISION OF GEOLOGICAL & GEOPHYSICAL SURVEYS 174° I EXPLANATION GEOTHERMAL SITES LAND STATUS Geothermal site, 90°C > reservoir temperature State land (patented or approved) Geothermal site, 90°C < reservoir temperature <150° ; ; oe ; ; : : ; ; ake nS \ oe : i : : SBE Native land (patented or approved) : . : : oo : oO . : Oo DO — : : : : : 3 W.. rd Me _Fumaro ‘ 56° Geothermal site, 150°C > reservoir temperature Geothermal site, reservoir temperature unknown eyed Geothermal well Wilderness land Geothermal gradient test hole’ National park, monument, wildlife refuge, and forest; |_(*Celsius/km) not classified as wilderness Federal land managed by Bureau of Land Management; may include selections by state or natives (Above classifications may include private land) GEOLOGY? Quaternary volcanic rocks = Sea reservoir temperature (°C) GEOTHERMAL DATA 2? Site not verified during this study na Not applicable -- No data Surface temperature (°C) (spring), {fumarole)—~ Convective heat discharge le 99°,'97° by spring flow (MW) Total dissolved solids (mg/l) Jurassic to Tertiary plutonic rocks METRIC CONVERSION FACTORS 1 meter = 3.281 feet 1 liter = 0.2642 gallon 1 milligram/liter = 1 part per million °C = 5/9 (°F - 32) °F = 9/5 °C + 32 * Quaternary caldera (numbered; see table 2) * Quaternary volcanoe (most are numbered; see table 2) Quaternary vent (unnumbered) 1Geothermal gradient data from Katzenstein and Whelan (1985), Republic Geothermal, inc. (1983, 1984, 1985) and Turner and others (1980). : CSS 4 f ; é e ¢ : fi ql g 3 2From Beikman (1974a, 1974b, 1975, 1980), Burk (1965), and Luedke and Smith (1986). . : . : es wk yras a : awar d Meridian. é several minor oo + : ‘ d dikes (Burk j dikes, pillow : ox : oe / ‘ ORIN Gees REN STER SD oe Mee tage z 55° TEIN — end of Unima N., long 162°08'24" W., Cold a co ) 1:250,000 Quadrangle, sec. 16, T. 56 S., R. 84 W., ' ' . 7 Seward Meridian. Two clusters of hot springs (com- PEAS ae Pe] 54° Mb ERS 54° 53° ae 53° nad A alana a: : re ms F : hra er r g : oe oe os : : p exploratory geothermal well me, Seite eo inbred el sp : : : \ drilled near the head of Makushin Valley produced I laska to use geothermal energy for electric-power 4 : j Boe ee oe 195°C water. The thermal resource can probab! at several spring vents. production. A synopsis of some thermal zones that . A oe : : ? oe : : s : p ly 52° diy caves, and a “DutevHarberacdUnaeskaoniondsclentedbyme, : — ’ . ; | : as | with a post Pleistocene pyrociastic flow, Quater- : Corpo! under terms of the oe : 4 O10 : é oe My k oS : S nary lava tlows and pyroclastic rocks trom Makushin : ‘ Volcano lie tothe north and west. ee —<— — en — il. flan POS : oo : : _forite pluton, The pluton intrudes the Unalaska = at 59°49 "04". long 166°54'26" W. Unalaska : . 4, : ’ ‘ oe : - 21. SUMMER BAY 52° oF — . West of Nikoiski Vilage on Umnak island Waring oo i — Fr atration ana 5 unconforvety ovata by _ 1:250,000 Quadiangle, sec. 16,7. 73S.,R. 120W., - A ey oo — oo : : : : a ; j oo a : : Makushin lavas. Watets emanate either direclly = === Seward Meridian. Sulfate-rich chloride springs with _feolosietecamcm canes enn ee home Big the ution from ts comact aureats or “has not been substantiated Theislandisclassified = oo oe a : oe oe : : : on as wilderness in the Aleutian Islands National Wild. tees > Chuginadak Island consisis of two east-west- aligned Quatemary voleanoes (Beikman, 1980). ow discharge and moderate temperatures (30° to — iet Valley is a 10 km long, 3 to oe — . oe haped valley that trends northeast os ? ¢ : ‘ : s ; Nome, Lat'9°S3'08"N., long 166°26'54" W,, Unalaska and heads on Makushin Voleano. Springs emerge — pee : x é a : : : j ‘ *4:250,000 Quadrangle, sec. 8,1. 73. S..R.117 W. trom alluvium in warn, shallow ponds and marshy : cs : 4 | : ( Oe ni SN Seward Maridian, Warm springs (36°C). emerge _ from alluvium intoa shallow pool near the base ofthe Lat 52°18" N, -4:250,000 Quadrangl eward Meridian. Based on 19th-c Mount Cleveland, the westetn stratovoleano, is one. ofthe most active volcanoes inthe Aleutian chain. last erupted in 1987 (Myers, 1990). : teas where tributary streams enter Glacier Valley. ‘The springs lie near of on faults. Water chemistry suggests the spring waters ate related to thermal. activity at the head of Glacier Valley. These springs east slope of a north-south-trending valley, 2 km ~ south of Summer Bay. The spring has road access from Unalaska village, 5.5 km to the southwest, In fall 1980, two shallow test wells encountered slightly Information, Waring (1917)reponiedhotspringsand = a Sas oo oo a ee : Os : a : Oe are 5 km northeast of Makushin Bay and 27 km : Tos é ‘ , oe : : thud pots on Seguam Island, 100 km northeast of ee — Os ok oe noe Co os S ri iss oe oS oe a : southwest of the villages of Dutch Harbor and oe ae ’ ae ‘ oo saline, warm water (44° to 80°C) under artesian Aika Island, {n 1987, a thermally active zone was : — ——s —CS—sti‘“‘isO—r—————C“‘C‘CRS : ~~ sis Uinta. Lands in the area have been selected by 4 " : 5 : ce : pressure at a depth of 13 m (Reeder, 1981). Lands: observed southo/ Pyre Peak (Myers, 1980). Seguam me : — Ce Soe a oe Pe Oe the Ounalashka Native Corporation under terms of in the area have been selected by the Ounalashka - is classified as wildemess in the Aleutian Island ‘the Alaska Native Land Claims Settlement Act. Native Corporation under terms of the Alaska Native. : ‘The lower part of Glacier Valley contains debris Land Claims Settlement Act. : oo . flaws, glacial ddft, alluvium, and colluvium and ts a : § 7 . < Suromer Bay valley is covered with alluvial underlain by the Unalaska Formation, a thick = ‘ ; : eo ' ; : S deposits. Bedrock consists of the Unataska Forma { fine sedimentary and. ‘ Oe eC & y SOO. S x tian (described under Makushin geothermal area) tspringliesnear : (a4 | a Re _ cut by west-northwest-trending feldspathic basalt, oe OS : eae 8 porphyry dikes. Basaltic chips from 17m depth 51° _wete recovered from diiiholee ee | 174° : : Base modified from Arctic Environmental Information and Data Center, Cartography by N.D. Bowman Southeast Alaska, 1978. Revised December 1981. Universal Transverse SCALE 1:1,000,000 Mercator projection. 10 0 10 20 30 40 50 miles LOCATION INDEX 10 0 10 20 30 40 50 kilometers CONTOUR INTERVAL 1000 FEET % oO DATUM MEAN SEA LEVEL GEOTHERMAL RESOURCES OF THE ALEUTIAN ARC, ALASKA Part 2 - Central Arc Sheet 1 By Roman J. Motyka, Shirley A. Liss, Christopher J. Nye, and Mary A. Moorman 1993 ALASKA DIVISION OF GEOLOGICAL & PROFESSIONAL REPORT 114 GEOPHYSICAL SURVEYS Motyka and others 1993, sheet 1 of 4 172° 174° / 7 EXPLANATION 180° 176° ; ; 1 74° Pea ie oe 0 Wate GEOTHERMAL SITES LAND STATUS @ i °, ; Geothermal site, 90°C > reservoir temperature Native land (patented or approved) ®@ Geothermal site, 150°C > reservoir temperature . Military land oe © Geothermal site, reservoir temperature unknown 4. Geothermal gradient test hole’ || Wilbetnges tae (°Celsius/km) > > Y oe @ ( ; ; : 4 Heat flow measurement site? (Above classifications may include private land) : : - : : ; - : Ne - oO oo : ce a : — . . : 56° (Milliwatts/m?) : oe GEOTHERMAL DATA 3 2? Site not verified during this study GEOLOGY: -- No data Surface temperature (°C) Quaternary volcanic rocks Convective heat discharge (spring), fumarate) g9° fo7s 0.15 x by spring flow (MW) 169°. * Quaternary caldera (numbered; see table 2) A 553 Be METRIC CONVERSION FACTORS * Quaternary volcano (most are numbered; see table 2) Total dissolved solids (mg/l) Mean reservoir temperature (°C) 1 meter = 3.281 feet 1 liter = 0.2642 gallon * Quaternary vent (unnumbered) 1 milligranvliter = 1 part per million °C = 5/9 (°F - 32) °F =9/5 °C +32 54° ~7Geothermal gradient data from Katzenstein and Whelan (1985), Republic Geothermal, Inc. (1983, 1984, 1985) and Tumer and others (1980). 2Heat flow data from Ballard and others (1991), Lawver and others (1979), and Sass and Monroe (1970). 3From Beikman (1974a, 1974b, 1975, 1980), Burk (1965), and Luedke and Smith (1986). 55° 53° | 54° 52° 73 53° oO - a Re aN S 2 51° 52° | : : oo So oo : - ome me : a 176° 174° 174 176 178 0 Cartography by N.D. Bowman Base modified from Arctic Environmental Information and Data Center, Southeast Alaska, 1978. Revised December 1981. Universal Transverse SCALE 1:1,000,000 Mercator projection. 10 0 40 20 30 40 50 miles | SE LOCATION INDEX 10 0 10 20 30 40 50 kilometers CONTOUR INTERVAL 1000 FEET DATUM MEAN SEA LEVEL & o GEOTHERMAL RESOURCES OF THE ALEUTIAN ARC, ALASKA cy LQ | Part 1 - Western Arc weg By Roman J. Motyka, Shirley A. Liss, Christopher J. Nye, and Mary A. Moorman 1993