Investigations of the Dunes Geothermal Anomaly,Imperial Valley,California:Part 1. Geochemistry of Geothermal Fluids,

摘要

A geothermal test corehole, DWR Dunes No. 1,was drilled in the Dunes geothermal anomaly by the State of California Department of Water Resources. Water samples from this geothermal system were collected from perforations at 109and 260meters depth. These water samples were analyzed for chemical and isotopic composition. These tests indicate that the source of the geothermal fluid is partially evaporated Colorado River water. An investigation of chloride/bromide ratios was used to determine the source of the salt in the geothermal fluid from Dunes. The result may suggest that the salt in the Salton Sea geothermal system and in the Dunes geothermal anomaly is derived from the Colorado River and that this water has not done any leaching or been mixed with water from other sources. It was determined that further geophysical studies (gravity,seismic refraction,electrical resistivity,and magnetotelluric sounding) are needed to locate the reservoir of geothermal fluid in the Dunes system.