Title: Stable isotope systematics of oxygen and carbon in and around the Cerro Prieto geothermal anomaly, Baja California, Mexico
Abstract: Rock samples from a total of 50 drillholes in the Cerro Prieto geothermal area have been analyzed by stable isotopic techniques. In particular, calcite in cuttings and core samples from these wells have been analyzed to observe systematic variation in carbon (delta/sup 13/C) and oxygen (delta/sup 18/O) isotopic compositions. Consistent behaviors of these isotopic systems were observed and provide a large amount of information on the processes of calcite-water isotopic equilibration, dissolution-precipitation and descarbonation occurring within and around the reservoir. Oxygen isotopic equilibration of calcite and the geothermal fluid provides a useful indicator of the variations of temperature throughout the area before the drilling of geothermal wells. Data on several additional wells drilled into previously unexplored areas and depth intervals have been accumulated to permit clarification of details in the three-dimensional picture of the Cerro Prieto thermal anomaly. Long-term natural flow directions within the geothermal system can often be inferred directly from the three-dimensional distribution of temperatures within the field. Within the geothermal reservoir, a gradual disappearance of calcite, with increasing temperature, correlates generally with a slight decrease in delta/sup 13/C of the calcite. Although this pattern is nearly identical to the isotopic changes occurring during descarbonation of calcite inmore » skarn areas, it is probable that other processes involving dissolution by the brines or isotopic exchange with an external carbon reservoir are also locally important.« less
Publication Year: 1982
Publication Date: 1982-08-10
Language: en
Type: article
Access and Citation
Cited By Count: 1
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot