Water Sampling At Valles Caldera - Sulphur Springs Area (Rao, Et Al., 1996)

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Exploration Activity: Water Sampling At Valles Caldera - Sulphur Springs Area (Rao, Et Al., 1996)

Exploration Activity Details
Location Valles Caldera - Sulphur Springs Geothermal Area
Exploration Technique Water Sampling
Activity Date 1982 - 1996
Usefulness useful
DOE-funding Unknown

Isotopic analysis of waters sampled from 3 meteoric-dominated springs, 7 high-temperature drill holes, and 6 surface hot springs was conducted to determine fluid pathways and the origin of chloride in the system. Most of the samples analyzed during this investigation were analyzed for their hydrogen and oxygen isotope contents as a part of previous studies (Goff & Grigsby, 1982; Vuataz & Goff, 1986). The present study focuses on the interpretation of 36Cl- concentrations of the water samples measured by accelerator mass spectrometry (AMS). 36Cl/Cl ratios indicate that deeply circulating meteoric waters derive their high chloride contents from Precambrian basement and Paleozoic rocks before ascending into more shallow volcaniclastic reservoirs, and that residence times for these waters are <100,000 years. 36Cl/Cl ratios also confirm previous classifications of the sampled waters as meteoric or thermal waters established by previous stable isotope results (Vuataz & Goff, 1986).


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