Chemical Geothermometry and Numerical Unmixing of the Diluted Geothermal Waters of the San Bernardino Valley Region of Southern California

Abstract

Multicomponent chemical equilibrium model, conventional geothermometers, and ternary moladlity plots of selected components in San Bernardino Valley waters indicate al low to moderate temperature geothermal component is diluted an cooled by shallow groundwater's. At Arrowhead Hot Springs, 80-90°C waters flow from fractured basement complex along a shear zone associated with the San Andreas fault system. Equilibrium models indicate 100-120°C for waters at depth of this deeply circulated water compositionally resembles fault zones in the adjacent structural basins. Geothermal wells aligned on the Loma Linda fault zone in the South San Bernardino KGRA produce highly mixed waters with maximum temperatures of 60--65°C. Results of numerical modeling suggest temperatures of about 80-85°C for the to water component that comprised 30 to 40% of the productions from the wells. One geothermal well at nearly Harlem Hot Springs KGRA is 40°C downhole and about 40% of the well prediction is a hot water component that may be 55-65°C at depth.