Late Pleistocene lakes and wetlands, Panamint Valley, Inyo County, California

Pleistocene deposits in Panamint Valley, California, document the changes in pluvial lake level, source water, and elevation of the regional groundwater table associated with climate change. The oxygen isotope stage (OIS) 2 and 6 lacustrine record is well preserved in surficial deposits, whereas the OIS 3-5 lacustrine-paludal and lacustrine record is mainly derived from an archived core sample. Amino acid racemization ratios in ostracodes and gastropods suggest that the shoreline and groundwater-discharge features that lie between ∼600 and 550 m elevation formed during one highstand, probably during OIS 6. A fossiliferous part of the ∼100-m-deep core DH-1, which was drilled in the Bal-larat Basin during the late 1950s, was resampled in this study. Comparison of DH-1 with core DH-3 from Panamint Valley and core OL-92 from Owens Lake suggests the 34-78-m-depth interval of DH-1 may span all or much of OIS 4. The microfauna from this depth interval indicate a saline marsh or shallow lacustrine environment, but not a large lake. The ostracode assemblage requires low ratios of alkalinity to calcium (alk/Ca) water likely indicative of solutes in deep regional groundwater sources rather than the high alk/Ca solutes common to the Owens River system. OIS 2-aged sediment from surficial deposits, a shallow auger hole, and core DH-1 contain faunas, including the ostracode Limnocythere sappaensis, which require the high alk/Ca evolved solutes common to the Owens River. The elevation of the lacustrine sediments further indicates a moderate-sized saline lake around 180-200 m depth. In the northern Lake Hill basin, a saline lake persisted until at least 16 ka, and it was succeeded by fresh, groundwater-supported wetlands, which were fully developed by ca. 12,575 ¹⁴ C yr B.P. and which persisted until around 10,500 ¹⁴ C yr B.P., when the basin became a dry playa.