Climatic Changes Inferred From Analyses of Lake-Sediment Cores, Walker Lake, Nevada.

摘要

Organic and inorganic fractions of sediment collected from the bottom of Walker Lake, Nevada, have been dated by carbon-14 techniques. Sedimentation rates and the organic-carbon content of the sediment were correlated with climatic change. The cold climate between 25,000 and 21,000 years ago caused little runoff, snow accumulation on the mountains, and rapid substantial glacial advances; this period of cold climate resulted in a slow sedimentation rate (0.20 millimeter per year) and in a small organic-carbon content in the sediment. Also, organic-carbon accumulation rates in the lake during this period were slow. The most recent period of slow sedimentation rate and small organic-carbon content occurred between 10,000 and 5500 years ago, indicative of low lake stage and dry climatic conditions. This period of dry climate also was evidenced by dry conditions for Lake Lahontan in Nevada and Searles Lake in California, as cited in the literature. Walker Lake filled rapidly with water between 5500 and 4500 years ago. The data published in this report was not produced under an approved Site Investigation Plan (SIP) or Study Plan (SP) and will not be used in the licensing process. 10 refs., 3 figs., 2 tabs. (ERA citation 14:027119)