Late Quaternary arid/humid cycles in the Mojave Desert and western Great Basin of North America

This paper discusses the late Quaternary environmental changes that occurred in the drylands of western North America, with particular emphasis on the aeolian/lacustrine record from the Mojave Desert. The Basin and Range Province (which includes the Great Basin and the Mojave, Sonoran and Chihuahuan deserts), the primary physiographic region within the. North American arid zone, is characterized by a wide variety of landforms within a predominantly endoreic, block-faulted, tectonic setting. In these closed drainage basins, lacustrine and aeolian geomorphic features and sediments, have provided some of the best records for deciphering environmental changes. About 100 of the basins contained lakes during the Last Glacial Maximum (LGM). At larger temporal scales (Milankovitch, Dansgaard-Oeschger cycles), lake levels seem to be well correlated with large-scale atmospheric circulation controls, such as the higher lake stands associated with wetter than present conditions in the southwestern drylands during the LGM. On the other hand, aeolian deposition was highly episodic during late Quaternary time and is believed to be largely controlled by variations in sediment supply and production, storage and transport capacity. (C) 2002 Elsevier Science Ltd. All rights reserved.