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Title: The Geyser Bight geothermal area, Umnak Island, Alaska

Abstract

The Geyser Bight geothermal area contains one of the hottest and most extensive areas of thermal springs in Alaska, and is the only site in the state with geysers. Heat for the geothermal system is derived from crustal magma associated with Mt. Recheshnoi volcano. Successive injections of magma have probably heated the crust to near its minimum melting point and produced the only high-SiO[sub 2] rhyolites in the oceanic part of the Aleutian arc. At least two hydrothermal reservoirs are postulated to underlie the geothermal area and have temperatures of 165 and 200 C, respectively, as estimated by geothermometry. Sulfate-water isotope geothermometers suggest a deeper reservoir with a temperature of 265 C. The thermal spring waters have relatively low concentrations of Cl (600 ppm) but are rich in B (60 ppm) and As (6 ppm). The As/Cl ratio is among the highest reported for geothermal waters. 41 refs., 12 figs., 8 tabs.

Authors:
 [1];  [2];  [3];  [4]
  1. (Alaska Div. of Geological and Geophysical Surveys, Juneau, AK (United States))
  2. (Alaska Div. of Geological and Geophysical Surveys, Fairbanks, AK (United States) Univ. of Alaska, Fairbanks, AK (United States). Geophysical Inst.)
  3. (Univ. of Alaska, Fairbanks, AK (United States). Geophysical Inst.)
  4. (Alaska Div. of Geological and Geophysical Surveys, Fairbanks, AK (United States))
Publication Date:
OSTI Identifier:
5569894
DOE Contract Number:
FG07-88ID12742; FG07-88ID12744
Resource Type:
Journal Article
Resource Relation:
Journal Name: Geothermics (International Journal of Geothermal Research and its Applications); (United States); Journal Volume: 22:4
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; ALASKA; KGRA; GEOLOGY; COMPILED DATA; GEOCHEMISTRY; GEOTHERMAL FLUIDS; ISOTOPE DATING; MAPS; WATER CHEMISTRY; AGE ESTIMATION; CHEMISTRY; DATA; DEVELOPED COUNTRIES; FLUIDS; INFORMATION; NORTH AMERICA; NUMERICAL DATA; USA; 150200* - Geology & Hydrology of Geothermal Systems

Citation Formats

Motyka, R.J., Nye, C.J., Turner, D.L., and Liss, S.A.. The Geyser Bight geothermal area, Umnak Island, Alaska. United States: N. p., 1993. Web. doi:10.1016/0375-6505(93)90005-8.
Motyka, R.J., Nye, C.J., Turner, D.L., & Liss, S.A.. The Geyser Bight geothermal area, Umnak Island, Alaska. United States. doi:10.1016/0375-6505(93)90005-8.
Motyka, R.J., Nye, C.J., Turner, D.L., and Liss, S.A.. 1993. "The Geyser Bight geothermal area, Umnak Island, Alaska". United States. doi:10.1016/0375-6505(93)90005-8.
@article{osti_5569894,
title = {The Geyser Bight geothermal area, Umnak Island, Alaska},
author = {Motyka, R.J. and Nye, C.J. and Turner, D.L. and Liss, S.A.},
abstractNote = {The Geyser Bight geothermal area contains one of the hottest and most extensive areas of thermal springs in Alaska, and is the only site in the state with geysers. Heat for the geothermal system is derived from crustal magma associated with Mt. Recheshnoi volcano. Successive injections of magma have probably heated the crust to near its minimum melting point and produced the only high-SiO[sub 2] rhyolites in the oceanic part of the Aleutian arc. At least two hydrothermal reservoirs are postulated to underlie the geothermal area and have temperatures of 165 and 200 C, respectively, as estimated by geothermometry. Sulfate-water isotope geothermometers suggest a deeper reservoir with a temperature of 265 C. The thermal spring waters have relatively low concentrations of Cl (600 ppm) but are rich in B (60 ppm) and As (6 ppm). The As/Cl ratio is among the highest reported for geothermal waters. 41 refs., 12 figs., 8 tabs.},
doi = {10.1016/0375-6505(93)90005-8},
journal = {Geothermics (International Journal of Geothermal Research and its Applications); (United States)},
number = ,
volume = 22:4,
place = {United States},
year = 1993,
month = 8
}
  • The Geyser Bight geothermal area is located on Umnak Island in the central Aleutian Islands. It contains one of the hottest and most extensive areas of thermal springs and fumaroles in Alaska, and is only documented site in Alaska with geysers. The zone of hot springs and fumaroles lies at the head of Geyser Creek, 5 km up a broad, flat, alluvial valley from Geyser Bight. At present central Umnak is remote and undeveloped. This report describes results of a combined program of geologic mapping, K-Ar dating, detailed description of hot springs, petrology and geochemistry of volcanic and plutonic rockmore » units, and chemistry of geothermal fluids. Our mapping documents the presence of plutonic rock much closer to the area of hotsprings and fumaroles than previously known, thus increasing the probability that plutonic rock may host the geothermal system. K-Ar dating of 23 samples provides a time framework for the eruptive history of volcanic rocks as well as a plutonic cooling age.« less
  • Several fumarole fields and numerous thermal springs occur on the eastern flanks of Makushin volcano. The thermal springs at Makushin are typically near-neutral in pH, have very low chloride levels (10 ppm), and are comparatively rich in Mg, Ca, SO/sub 4/, HCO/sub 3/ and SiO/sub 2/. Similarities in cation and isotopic compositions of Makushin thermal springs and local surface streams indicate the thermal waters are locally derived meteoric waters. These surface waters infiltrate to relatively shallow depths where they are heated by steam and gases rising from a vapor-dominated zone. Predominate fumarolic gases are CO/sub 2/, N/sub 2/, and sulfurmore » gases. All samples showed a significant level of H/sub 2/ and a high H/sub 2//CH/sub 4/ ratio. The ratio of He//sup 4/He WRT atmospheric levels range from 4.5 to 6.0. Fumaroles and hot springs in the upper parts of Glacier and Makushin Valleys form a roughly linear trend, suggesting their distribution may be structurally controlled.« less
  • Large vapor-dominated hydrothermal reservoirs are suspected to exist in the region marked by fumarole fields on the southeast flank of Makushin Volcano on Unalaska Island, Alaska. In this paper, economic and engineering considerations with respect to potential hydrothermal development in the Makushin Volcano region are presented.
  • A rapid expansion in the seafood industry and projected oil, gas and mining developments have resulted in a shortage of power on Unalaska Island. Currently, all power is supplied by small diesel generators at a cost of 340 mills/kwh for the local utility system. Available data indicate the potential for a significant high temperature geothermal resource on Makushin Volcano, west of the town of Unalaska. A summary of the considerations affecting the development of the Makushin resource to supply power to Unalaska is presented. A preliminary economic analysis of various resource and development assumptions indicated that geothermal power can bemore » competitive with diesel power even though capital investment is high.« less
  • A study was conducted to obtain baseline data on trace metal levels in zooplankton from New York Bight and Long Island Sound, and to determine any differences in metal levels related to geographical location of sampling. It was shown that the levels of silver, cadmium and nickel in plankton did not differ markedly for the various locations. Silver levels ranged from 0.5 to 1.4 ppM in all samples, whereas Cd levels were in the range of 0.5 to 2.4 ppM and Ni levels ranged from 0.9 to 4.6 ppM for all samples. Most lower limits for Cr were less thanmore » 7 ppM which the highest level was 35.2 ppM. The copper, lead, and zinc levels in zooplankton obtained from the New York Bight varied greatly as a function of either species or geographic location.« less