ESD
The Center for Isotope Geochemistry
project with researchers from the U.S. Geological Survey and Oxbow Geothermal, it is shown that noble gas concentrations, water isotopes and chloride concentrations in geothermal production streams provide a quantitative measure for tracing the return of injectate to geothermal reservoirs. The rate at which cooler injectate fluids invade a production reservoir is extremely important for establishing injection programs and constraining future reservoir models. Other research has shown that co-variations between helium and neodynium isotopes in continental basalts can be used to differentiate between magma sources or chambers and to assess the present rate of magma chamber recharge with new mantle material.This provides valuable information for assessing volcano hazards and the potential of a region for geothermal energy development. The drift-scale heater test at Yucca Mountain, Neva d a , the proposed nu clear waste repository site, is being conducted to test the effect of heat generated by the stored nu clear waste. Researchers a re monitoring the time evolution of the CO2 carbon isotopic composition in gas released during the heating test.The changing isotopic composition will help quantify factors such as the degree of porewater degassing and identify zones of calcite deposition within the therm a l ly disturbed re gion which bear dire c t ly on fluid movement and changing perm e ability of the system. The Environmental Measurements Laboratory (EML) consoli-
dates the inorganic and organic chemical analytical facilities of the Earth Sciences Division.The EML provides chemical characterization of soil, rock, mineral and fluid samples for many researchers and projects within the division and the UC campus. The EML is equipped with state-of-the-art instrumentation, including ICP-MS with laser ablation capabilities, atomic adsorption spectrometry, GC/MS, HPLC, and facilities for standard wet chemical analysis.
Funding The research of the Center for Isotope Geochemistry has been supported by the Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering and Geosciences divisions; the Environmental Science Management Program; the Office of Energy Efficiency and Renewable Energy, Office of Geothermal Technologies; the U.S. Environmental Protection Agency, via Energy Efficiency and Renewable Energy, Office of Building Technologies and State Community Programs of the U.S. Department of Energy. Research has also been supported by the U.S. Navy; the Office of Space Science of the National Aeronautics and Space Administration; the Office of Polar Programs of the National Science Foundation; and the LBNL Laboratory Directed Research and Development Program.
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