X-Ray Diffraction (XRD) At Long Valley Caldera Geothermal Area (Flexser, 1991)

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Exploration Activity: X-Ray Diffraction (XRD) At Long Valley Caldera Geothermal Area (Flexser, 1991)

Exploration Activity Details
Location Long Valley Caldera Geothermal Area
Exploration Technique X-Ray Diffraction (XRD)
Activity Date 1985 - 1988
Usefulness useful
DOE-funding Unknown

Exploration Basis
Sorey et al. (1991) integrated information from previous scientific and private industry investigations with new data obtained from fluid sampling, test drilling, and geological and geophysical studies conducted between 1985-1988 into a comprehensive conceptual model of the present-day hydrothermal flow system at Long Valley caldera. Lithology and temperature gradient data from wells drilled prior to 1988 are summarized in detail in the compilation, which includes information from numerous wells described in previous studies, and data from many of the wells are available online through the U.S. Geological Survey (Farrar et al., 2010). Thermal conductivity, XRD, and isotopic analyses of core cuttings from several of the wells discussed have been completed in several studies, and seem to prove useful in most cases (Flexser, 1991; Goff et al., 1991; Smith and Suemnicht, 1991). Results from these studies are also summarized in Sorey et al. (1991). Relevant data from chemical and isotopic studies published during the same year are also considered in the review.
"Detailed XRD studies of alteration mineralogy in west-moat drill holes (Flexser, 1989, 1991-this volume) show that the present temperatures in RDO-8, PLV-1, and INYO-4 are well below (65°C or more) alteration temperatures, except in the lower part of RDO-8 (below about 300 m). No XRD evidence of epidote or other relatively high-temperature ( > 230°C) alteration products was found in any of the core."

Additional References