Be in the Salton Sea Geothermal System, California (USA): Salton Sea Scientific Drilling Project, California State 2-14 Well: Final Report

摘要

The Salton Sea Geothermal System lies in the old Colorado River Delta, where sediments have been metamorphosed by hydrothermal processes. Fluids, from well Fee No. 5 and deep hole SSSDP California State 2-14, as well as rocks from the deep hole were studied for (sup 10)Be and (sup 9)Be. In the solid samples (sup 10)Be concentration ranges from 29 to 259 X 10(sup 6) atom/g and (sup 9)Be from 0.49 to 2.52 ppM. The (sup 10)Be concentration in the geothermal waters ranges from 2 X 10 (sup 3) to 2.9 X 10(sup 6) atom/g and (sup 9)Be from 0.7 to 16.6 ppB. Compared to the steady-state inventory which represents the quantity of sup 10 Be expected from rain deposition alone (/approximately/1 X 10 (sup 12) atom/cm( sup 2)), the (sup 10)Be inventory in the deep core is 3 orders of magnitude higher (>1 X 10 (sup 15) atom/cm(sup 2)). This indicates that most (sup 10)Be is inherited and that the sediments hosting the geothermal field down to 3250m are young, less than few million year old. (sup 10)Be and (sup 9)Be Kds decrease from surface to bottom (3333 to 48 and 727 to 393, respectively) expressing the strong leaching effect of the solid material by the geothermal waters. This process is more active at depth where pH is