HYDROLOGIC AND CLIMATIC IMPLICATIONS OF LATE QUATERNARY PALEOLAKES IN THE SOUTHERN BASIN AND RANGE PROVINCE

Relative changes in the surface areas of late Pleistocene paleolakes in the southern Basin and Range province (SBAR), as reconstructed from relict shoreline features, mirror the precipitation-evaporation balance that characterized successive humid intervals. Well dated beach and near-shore deposits provide unambiguous constraints on the timing and paleohydrologic significance of these intervals, information that is otherwise difficult to detect in high-resolution time series—such as the speleothem d¹⁸O records from Carlsbad Caverns in New Mexico, and Cave-of-the-Bells in Arizona. Taken together, several shoreline chronologies from a region can reveal the strength and nature of inter-hemispheric teleconnections through comparison with proxy records of atmospheric and oceanic circulation. Unfortunately, a lack of knowledge about the history of lake area changes in the SBAR—largely due to ¹⁴C-related uncertainties and incomplete dating of shoreline deposits—has left great uncertainty about regional hydroclimate during the period of interest. Collectively, several studies reveal multiple lake level oscillations during and following MIS 3, including those from four paleolakes: one in central New Mexico (Estancia), two in southwestern New Mexico (Playas and Cloverdale), and one in southeastern Arizona (Cochise). In sum, there is evidence for high stand conditions in two or more paleolake basins prior to the Last Glacial Maximum (LGM) >28 cal Kyr BP (Ka), as well as during the LGM ~23-19 Ka, deglaciation ~17-14 Ka, and the Pleistocene-Holocene transition ~13-11.5 Ka. This presentation will examine shoreline evidence for regional hydrologic responses to changes in oceanic-atmospheric circulation that are distinctly expressed in global climate records, along with implications for atmospheric circulation patterns in western North America during late MIS 3 and MIS 2.