12:00 PM - 12:50 PM
Evidence for the persistence of large inland lakes in western North America during the Pliocene and Pleistocene provides first-order constraints on the regional water balance. In this talk I will discuss completed and ongoing work to investigate the climatological conditions driving lake levels in western North America during the mid-Pliocene warm period and Pleistocene glacial maxima. Geologic evidence suggests wet conditions persisted in this region during both periods despite dramatically different boundary conditions and pCO2 levels. I will present results of lake isotope mass balance modeling and compare them to climate model simulations of the Last Glacial Maximum (LGM) and mid-Pliocene produced by the Paleoclimate Modelling Intercomparison Project (PMIP and PlioMIP). Reduced evaporation and moderate increases in precipitation, relative to modern, led to moderate lake levels during the LGM. In contrast, larger precipitation increases may be the primary driver of lake levels during the Pliocene, suggesting a role for El Niño teleconnections during the mid-Pliocene.