The late Pleistocene of Death Valley: A climatic reconstruction based on macrofossil data

Abstract

Wood rat ( Neotoma) macrofossil deposits from Death Valley, California (northern Mohave Dessert), dating from the Wisconsinan glacial epoch provide a basis for reconstruction of the glacial-age climate at low elevations of the area. Elevational depression of the woodland zone (1200–1500 m relative to today), presence of a woodland/semidesert ecotone at approximately 450 m, and species composition of the low-elevation semidesert, which included a Yucca species ( Yucca whipplei), chaparral yucca) now locally extinct, point toward a Pleistocene climate which was less arid and more equable than today. Precipitation is estimated to have been three to four times the present values and summers 8–14°C cooler. The increase in precipitation is inferred to be part of a generally wetter regional in the northern Mohave Desert and the central Great Basin during the last glacial. Presence of warm-desert species at 10,200 yr B.P. indicates that climatic conditions similar to those of the present were established at the lower elevations by this time.