Abstract:
A semi-quantitative pollen index and stable isotopes of carbon and nitrogen are used to reconstruct late Holocene changes in moisture availability in the Darhad Basin, northern Mongolia. Palynomorphs extracted from cores of lake Dood indicate that the surrounding Darhad Basin was much wetter at 4,200 cal. yrs B.P. Beginning at 2,900 cal. yrs B.P., humidity in the Darhad Basin decreased until 300 cal. yrs B.P. Humidity and warmth returned briefly during the Medieval Warm Epoch, from 1,370 to 930 cal yrs B.P. (AD. 580 to 892). Increasing proportions of forest to steppe pollen types suggests a response to warmer summer temperatures and/or increased moisture during the 20th century warming. Differences in lake levels between lakes Dood, Telmen (300km to the south), and Hövsgöl (60km to the east), suggest that available moisture varies over short distances. Temperature changes driven by solar insolation appear to exert significant control over the regional water budgets of both lake Telmen and lake Hövsgöl, whereas moisture availability in the lake Dood region is affected by changes in atmospheric circulation over Eurasia.
