Lake Ivanpah: An overlooked pluvial lake in the southern Great Basin, U. S. A.

A long-held but untested hydroclimatic model maintains that, in the arid southern Great Basin, U.S.A., hydrographically isolated watersheds held no late Quaternary paleolakes, even during pluvial periods. We test this at Ivanpah Dry Lake, which has a watershed lying wholly within mountains of Mojave Desert, and obvious ancient shorelines. Remote imagery was used to identify relict geomorphic features attributable wave action high-lake stands, excavations different parts basin margin revealed beach lacustrine sedimentary sequences, some truncated by playa surfaces, most >2.5 m above current playa. In exposed sediment grades upward near-shore muds, capped alluvium Cima Wash Delta-Fan. Time-dependent changes carbon isotope ratios indicate that saltscrub (Atriplex polycarpa), desert vegetation surrounding dry lake today, did not become dominant until after 5.4 cal ka. comparison Paleolake Ivanpah’s initial radiocarbon chronology regional proxies demonstrates its potential inform on changing sources moisture contributing events. This study shows only lakes occurred also margins these basins are so geomorphically active as entirely obscure evidence their occurrence. However, process often buries protects, rather than obliterates, stratigraphic for past stands. It margin, depocenter, is where should be sought. basin, Holocene paleolakes appear have persisted decades centuries.