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Investigations of the Dunes geothermal anomaly, Imperial Valley, California. Part IV. Geochemical studies of water, calcite, and silicates

Technical Report ·
OSTI ID:7328985

The Dunes geothermal system on the southeast margin of the Salton Trough exhibits a positive heat flow anomaly, a positive residual gravity anomaly, and electrical resistivity low, and a silicified cap rock emplaced in late Tertiary and Quaternary age sediments. Hydrogen and oxygen isotope studies of water samples indicate the source of the hydrothermal fluid is Colorado River water. Although not previously tested to such low temperatures, the quartz-water and alkali feldspar-water oxygen isotope geothermometers agree very well with the in situ temperature of 104C. The isotopic studies support the conclusions that silicification of the cap rock in the system occurred near the in situ temperature from Colorado River water. Two chemical geothermometers were tested. Chloride/bromide ratios were measured to determine the source of the salt in the hydrothermal fluid. The ratio Cl/Br in DWR Dunes No. 1, in the Salton Sea geothermal system, and in Colorado River water, is identical at 1600, suggesting that the salts in both of these geothermal systems are derived from the Colorado River.

Research Organization:
California Univ., Riverside (USA). Inst. of Geophysics and Planetary Physics
OSTI ID:
7328985
Report Number(s):
PB-259819; IGPP-UCR-75-20
Country of Publication:
United States
Language:
English