A desert responds to Pleistocene climate change: Saline lacustrine sediments, Death Valley, California, USA

A core taken in 1993 from the modern saltpan at Badwater Basin in Death Valley, California, USA recovered about 185 m of saline lacustrine sediments. The sediments reflect climate fluctuations during the last 200 ka, encompassing two major glacial-interglacial cycles. This paper describes sediments in the lower half of the core, dated from about 200 to 100 ka. Perennial saline lake black muds and associated evaporite sediments, deposited between about 186 and 120 ka, encompass over half of the lower core. They are bracketed by saline mudflat and saltpan/ephemeral saline lake facies. Halite dominates evaporite mineralogy in the lower core; primary growth textures and syndepositional alteration fabrics provide qualitative indicators of brine depth and stratification and subaerial exposure events. Paleotemperatures from fluid inclusions in halite and pseudomorphs of hydrohalite suggest a climate 10 to 15°C cooler than present, with winter lows below 0°C. The Amargosa River may have begun to drain into Death Valley sometime during the early phase of the perennial lake. Sierra Nevada runoff via a series of over flowing basins probably reached Death Valley briefly just before the end of the perennial lake phase. The perennial lake interval, which reflects increased precipitation regionally, began at the beginning of global glacial stage 6 and persisted through it into the early stage 5 interglacial. The appearance or growth of perennial lakes during glacial periods has been noted in other interior-drained valleys in the US Great Basin, opposite to the response of many global desert-latitude areas, which become drier during glacial periods.