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Title: Strontium isotope study of the VC-1 core hole and associated hydrothermal fluids and rocks from Valles caldera, Jemez Mountains, New Mexico

Abstract

Chemical and strontium isotopic analyses have been performed on 10 geothermal waters from the Valles caldera/Jemez Mountain region, as well as 10 rock samples collected in the VC-1 scientific core hole. The /sup 87/Sr//sup 86/Sr values of other rocks sampled in the Jemez Mountains have also been used in this study to understand relations between the fluids and rocks of the volcanically driven geothermal system and the lateral outflow plume, discharging down the Jemez fault zone. The strontium content of ground-water is linked to the host rock composition, the aquifer temperature, and therefore the solubility of Sr-containing minerals. Low Sr concentrations in the fluid are found with a high temperature and/or volcanic host rocks, whereas high Sr concentrations are characteristic of a low temperature and/or a Paloezoic sedimentary aquifer. Important variations of the /sup 87/Sr//sup 86/Sr value in hydrothermal waters (0.70842--0.72193) are related to chemical composition, Sr content, and host rocks. For VC-1 core samples, the Sr isotopic ratios are also markedly variable (0.70459--0.75686), low for the Quaternary volcanics and high for the Paleozoic sedimentary rocks. The same observation is made for other Jemez Mountains rocks (0.70465--0.8163) with, in addition, high /sup 87/Sr//sup 86/Sr values for Precambrian crystalline rocks. Amore » good correspondence is generally found between the waters and the reservoir rocks studied here, which indicates that isotopic equilibrium is rapidly attained. The following suite of hydraulically related fluids displays a progressive enrichment in radiogenic strontium: Baca wells (/sup 87/Sr--/sup 86/Sr = 0.7084--0.7094), VC-1 core hole at 483 m (0.7152--0.7154), Main Jemez Spring (0.7217), and Soda Dam (0.7219).« less

Authors:
; ; ;
Publication Date:
Research Org.:
Institut Mixte de Recherches Geexclamation; aothermiques, Bureau de Recherches Geologiques et Minieres, Orleans, France
OSTI Identifier:
6959276
Resource Type:
Journal Article
Journal Name:
J. Geophys. Res.; (United States)
Additional Journal Information:
Journal Volume: 93:B6
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; GEOTHERMAL WELLS; CHEMICAL ANALYSIS; NEW MEXICO; CALDERAS; HYDROTHERMAL SYSTEMS; GEOCHEMISTRY; ISOTOPE DATING; JEMEZ MOUNTAINS; PALEOZOIC ERA; SAMPLING; STRONTIUM ISOTOPES; THERMAL WATERS; VOLCANIC ROCKS; AGE ESTIMATION; ALKALINE EARTH ISOTOPES; CHEMISTRY; ENERGY SYSTEMS; FEDERAL REGION VI; GEOLOGIC AGES; GEOTHERMAL SYSTEMS; IGNEOUS ROCKS; ISOTOPES; MOUNTAINS; NORTH AMERICA; ROCKS; USA; WELLS; 150201* - Geology & Hydrology of Geothermal Systems- USA- (-1989)

Citation Formats

Vuataz, F, Goff, F, Fouillac, C, and Calvez, J. Strontium isotope study of the VC-1 core hole and associated hydrothermal fluids and rocks from Valles caldera, Jemez Mountains, New Mexico. United States: N. p., 1988. Web. doi:10.1029/JB093iB06p06059.
Vuataz, F, Goff, F, Fouillac, C, & Calvez, J. Strontium isotope study of the VC-1 core hole and associated hydrothermal fluids and rocks from Valles caldera, Jemez Mountains, New Mexico. United States. doi:10.1029/JB093iB06p06059.
Vuataz, F, Goff, F, Fouillac, C, and Calvez, J. Fri . "Strontium isotope study of the VC-1 core hole and associated hydrothermal fluids and rocks from Valles caldera, Jemez Mountains, New Mexico". United States. doi:10.1029/JB093iB06p06059.
@article{osti_6959276,
title = {Strontium isotope study of the VC-1 core hole and associated hydrothermal fluids and rocks from Valles caldera, Jemez Mountains, New Mexico},
author = {Vuataz, F and Goff, F and Fouillac, C and Calvez, J},
abstractNote = {Chemical and strontium isotopic analyses have been performed on 10 geothermal waters from the Valles caldera/Jemez Mountain region, as well as 10 rock samples collected in the VC-1 scientific core hole. The /sup 87/Sr//sup 86/Sr values of other rocks sampled in the Jemez Mountains have also been used in this study to understand relations between the fluids and rocks of the volcanically driven geothermal system and the lateral outflow plume, discharging down the Jemez fault zone. The strontium content of ground-water is linked to the host rock composition, the aquifer temperature, and therefore the solubility of Sr-containing minerals. Low Sr concentrations in the fluid are found with a high temperature and/or volcanic host rocks, whereas high Sr concentrations are characteristic of a low temperature and/or a Paloezoic sedimentary aquifer. Important variations of the /sup 87/Sr//sup 86/Sr value in hydrothermal waters (0.70842--0.72193) are related to chemical composition, Sr content, and host rocks. For VC-1 core samples, the Sr isotopic ratios are also markedly variable (0.70459--0.75686), low for the Quaternary volcanics and high for the Paleozoic sedimentary rocks. The same observation is made for other Jemez Mountains rocks (0.70465--0.8163) with, in addition, high /sup 87/Sr//sup 86/Sr values for Precambrian crystalline rocks. A good correspondence is generally found between the waters and the reservoir rocks studied here, which indicates that isotopic equilibrium is rapidly attained. The following suite of hydraulically related fluids displays a progressive enrichment in radiogenic strontium: Baca wells (/sup 87/Sr--/sup 86/Sr = 0.7084--0.7094), VC-1 core hole at 483 m (0.7152--0.7154), Main Jemez Spring (0.7217), and Soda Dam (0.7219).},
doi = {10.1029/JB093iB06p06059},
journal = {J. Geophys. Res.; (United States)},
number = ,
volume = 93:B6,
place = {United States},
year = {1988},
month = {6}
}