WATER BALANCE MODELING AND PALEOCLIMATE INVESTIGATION OF PLEISTOCENE PLUVIAL LAKE CLOVER, NEVADA, USA

The Great Basin was occupied by pluvial lakes of varying size during Pleistocene glaciations. Many of the smaller pluvial lakes, including Lake Clover, formed in the northern part of the Great Basin in Nevada and reached highstands during the Latest Pleistocene at ~17.0 cal. ka BP. Previous attempts to model the climatic conditions of Lake Clover and other small pluvial lakes have encountered obstacles, especially in estimating potential evaporation of the lake and watershed. An evaporation expression for modern lakes and watersheds is developed using meteorological data, including temperature and evaporation data from Ruby Lake, NV and monthly solar radiation measurements at Elko, NV. Potential evaporation is reproduced by the evaporation expression within 4% error of pan evaporation data at Ruby Lake for each month with available measurements (April through October). Meteorological data and the calibrated evaporation expression were combined in a water balance model to determine a broad range of possible temperature and precipitation conditions during the Lake Clover highstand.

These results were then combined with results of glacier mass balance models applied to the Ruby Mountains to narrow the range of possible climate conditions for the last glaciation in northeastern Nevada. Model results suggest that the Lake Clover highstand was accompanied by temperatures 7.4°C to 8.4°C less than modern, and precipitation 1.8 to 1.9 times modern values. These estimates strongly suggest that both colder and wetter conditions accompanied the highstands of pluvial lakes. Additional testing of the evaporation scheme and model sensitivity to precipitation and scale are needed before the model can be more broadly applied.