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Title: Alteration mineralogy of the Dixie Valley geothermal system, Nevada

Abstract

Petrographic studies along the Stillwater fault zone in Dixie Valley, Nevada document a variety of overlapping alteration assemblages that represent different physical and chemical conditions. At depth in the northern portion of the Dixie Valley geothermal field, wairakite, illite-smectite, and chalcedonic quartz are present in the hanging wall where measured, static and flowing temperatures are close to 248{degrees}C. Although the presence of wairakite is consistent with the observed temperatures, both the illite-smectite and chalcedonic quartz suggest lower temperature conditions. In outcrop, samples from the footwall of the Stillwater fault contain quartz, kaolin, smectite, dolomite, biotite, and epidote. Crosscutting relationships indicate that quartz and kaolin postdate formation of older biotite and epidote veins. The superposition of lower temperature assemblages (kaolin, dolomite, smectite) upon higher temperature minerals (biotite, epidote) characterizes the alteration in the footwall, whereas, the superposition of higher temperature minerals (wairakite) upon lower temperature phases (chalcedonic quartz, illite-smectite) is characteristic of the alteration in the geothermal reservoir within the hanging wall. This retrograde and prograde progression of alteration should be expected along this active normal fault as the footwall is uplifted and exhumed through time, and simultaneously, the hanging wall is down dropped.

Authors:
; ;
Publication Date:
OSTI Identifier:
494378
Report Number(s):
CONF-960913-
TRN: 97:002642-0053
DOE Contract Number:  
AC07-95ID13274
Resource Type:
Conference
Resource Relation:
Conference: Annual meeting of the Geothermal Resources Council, Portland, OR (United States), 29 Sep - 2 Oct 1996; Other Information: PBD: 1996; Related Information: Is Part Of Geothermal development in the Pacific rim. Transactions, Volume 20; PB: 886 p.
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; NEVADA; GEOTHERMAL RESOURCES; GEOTHERMAL FIELDS; GEOTHERMAL SYSTEMS; GEOCHEMISTRY; HYDROTHERMAL ALTERATION

Citation Formats

Lutz, S J, Moore, J N, and Benoit, D. Alteration mineralogy of the Dixie Valley geothermal system, Nevada. United States: N. p., 1996. Web.
Lutz, S J, Moore, J N, & Benoit, D. Alteration mineralogy of the Dixie Valley geothermal system, Nevada. United States.
Lutz, S J, Moore, J N, and Benoit, D. 1996. "Alteration mineralogy of the Dixie Valley geothermal system, Nevada". United States.
@article{osti_494378,
title = {Alteration mineralogy of the Dixie Valley geothermal system, Nevada},
author = {Lutz, S J and Moore, J N and Benoit, D},
abstractNote = {Petrographic studies along the Stillwater fault zone in Dixie Valley, Nevada document a variety of overlapping alteration assemblages that represent different physical and chemical conditions. At depth in the northern portion of the Dixie Valley geothermal field, wairakite, illite-smectite, and chalcedonic quartz are present in the hanging wall where measured, static and flowing temperatures are close to 248{degrees}C. Although the presence of wairakite is consistent with the observed temperatures, both the illite-smectite and chalcedonic quartz suggest lower temperature conditions. In outcrop, samples from the footwall of the Stillwater fault contain quartz, kaolin, smectite, dolomite, biotite, and epidote. Crosscutting relationships indicate that quartz and kaolin postdate formation of older biotite and epidote veins. The superposition of lower temperature assemblages (kaolin, dolomite, smectite) upon higher temperature minerals (biotite, epidote) characterizes the alteration in the footwall, whereas, the superposition of higher temperature minerals (wairakite) upon lower temperature phases (chalcedonic quartz, illite-smectite) is characteristic of the alteration in the geothermal reservoir within the hanging wall. This retrograde and prograde progression of alteration should be expected along this active normal fault as the footwall is uplifted and exhumed through time, and simultaneously, the hanging wall is down dropped.},
doi = {},
url = {https://www.osti.gov/biblio/494378}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Dec 31 00:00:00 EST 1996},
month = {Tue Dec 31 00:00:00 EST 1996}
}

Conference:
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