Rapid changes in Late Pleistocene precipitation and stream discharge determined from medium- and coarse-grained sediment in saline lakes

Abstract

Sediment-trapping investigations in Pyramid Lake, Nevada show that medium- to coarse-grained clastic sediments suspended in streamflow after periods of low flow can be transported several kilometers in plumes of freshwater discharged over the surface of a saline lake. Analogous conditions are postulated to explain changes in the abundance of detrital quartz in lake clay near the center of Estancia Basin, New Mexico during the Late Pleistocene. Abrupt increases in the abundance of quartz grains mark the onset of lake freshening, and ostracode and trace-metal proxies for salinity indicate repeated, brief episodes of streamflow and lake freshening during the Last Glacial Maximum (LGM).