EVIDENCE FOR A PLUVIAL LAKE HIGHSTAND IN WESTERN NEVADA DURING MARINE ISOTOPE STAGE 4

Smith Valley, in west-central Nevada, was occupied by pluvial Lake Wellington, which reached its final highstand of approximately 1,477-m elevation during late Pleistocene time. Evidence for Lake Wellington includes lacustrine deposits and shorelines, whose surface geomorphology, sedimentology, and stratigraphy were used to interpret lake history. Based on modern valley topography and Geographic Information Systems (GIS) modeling, Lake Wellington had a surface area of approximately 217 km² at its last highstand.

On the basis of soil development on lacustrine sediment, and a tephra layer within the sequence, the 1,477-m highstand of Lake Wellington occurred between 80 and 60 ka, approximately corresponding to Marine Isotope Stage (MIS) 4. Smith Valley provides the most complete evidence of a pluvial lake highstand in Nevada during MIS 4.