18O/16O ratios in cherts associated with the saline lake deposits of East Africa |
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| Authors: | James R O&#x;Neil Richard L Hay |
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| Institution: | U.S. Geological Survey, Menlo Park, California 94025, USA;Department of Geology and Geophysics, University of California, Berkeley, California 94720, USA |
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| Abstract: | The cherts formed from sodium silicate precursors in East African saline, alkaline lakes have δ18O values ranging from 31.1 to 44.1. The δ18O values correlate in general with lake salinities as inferred from geologic evidence, indicating that most chert was formed from its precursor in contact with lake water trapped at the time of deposition. A few of the analyzed cherts probably formed in contact with dilute meteoric water. From the widely varying δ18O values we conclude that precursors were transformed to chert in fluids of widely varying salinity and aNa+/aH+ ratio. |
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