A DIATOM RECORD OF CLIMATE AND HYDROLOGY FOR THE PAST 200 KA FROM OWENS LAKE, CALIFORNIA WITH COMPARISON TO OTHER GREAT-BASIN RECORDS

Diatoms from lake sediments beneath Owens Lake playa, Inyo County, Cal ifornia, document a nearly continuous paleolimnological record of clim ate and hydrologic change since the penultimate glacial-interglacial c ycle based on a chronology established by radiocarbon, tephrochronolog y, and paleomagnetic control. Freshwater planktic diatoms (especially species of Stephanodiscus), plagioclase feldspar-rich sediments with h igh magnetic susceptibility, and Juniperus-type pollen characterized t he penultimate glaciation at Owens Lake. Saline diatoms dominated in t he following interglacial period, and there are several episodes durin g which freshwater planktic diatoms became abundant between 100 and 50 ka that may represent interstadial climatic conditions. Saline diatom s fell to low values after 50 ka, but warm-season Aulacoseira species indicate episodes of significant summer precipitation in the hydrologi c balance of Owens Lake prior to the last glacial maximum. By 25 ka, g lacial environments were again characterized by abundant Juniperus, pl agioclase feldspar, and Stephanodiscus species. Generally arid Holocen e climates were recorded in Owens Lake by short-term fluctuations of s aline and freshwater diatoms, desiccation, and oolitic sediments barre n of diatoms. Comparison to paleoclimate records both noah and south o f Owens Lake suggest a southerly displacement of storm tracks originat ing from the Aleutian Low during glacial episodes. Published by Elsevi er Science Ltd.