Mid to Late Holocene moisture evolution of semi-arid Mongolia and its anti-phase relationship with monsoonal Asia
Marcel Bliedtner, Paul Strobel, Julian Struck, Maximilian Prochnow, Enkhtuya Bazarradnaa, Roland Zech
Abstract
The spatial and temporal interaction of the Westerlies and the Asian Summer Monsoon (ASM) are often suggested to drive the Holocene moisture evolution of semi-arid Mongolia and Central Asia, but so far, it has remained a controversial topic of debate. In this context, we established a high-resolution 7.4 cal ka paleohydrological record from Shireet Naiman Nuur in the central Mongolian Khangai Mountains using compound-specific biomarker δ2H analyses. Our results suggest that drier conditions from 7.4 to 3.6 cal ka BP and wetter conditions since 3.6 cal ka BP until present are indeed related to changes in atmospheric circulation pattern. A strong anti-phasing between our record and records in monsoonal Asia shows that ASM intensification during the Mid Holocene shifted the ASM limit and adjacent subsidence dry-zones northwards, leading to increased dryness at Shireet Naiman Nuur. Overall wetter conditions during the Late Holocene are related to negative North Atlantic Oscillation phases advecting moisture into central Mongolia and Shireet Naiman Nuur by southerly-displaced Westerlies.