A Middle Holocene Vegetation Record from the Mojave Desert of North America and its Paleoclimatic Significance

Abstract

Abstract Packrat middens from the McCullough Range, in the southeastern Mojave Desert of Nevada, record vegetation conditions during the periods 6800 to 5060 yr B.P. and 1250 yr B.P. to present. Their age and location are ideal to test for middle Holocene aridity; the period between 6800 and 5060 yr B.P. does appear to have been more arid than during the late Holocene period of record. This agrees with other evidence for middle Holocene aridity from the Southwest. Arguments for strengthened middle Holocene monsoons in the region are based chiefly on packrat midden samples older than 7500 yr B.P., or on samples that are younger than 5500 yr B.P. Simulations of 6000 yr B.P. climate that fail to show strong subtropical flow into the Southwest are therefore supported by evidence for enhanced aridity in that region.