OPTICAL DATING OF HOLOCENE DUNE SANDS FROM THE HULUN BUIR DESERT, NORTHEASTERN CHINA

Abstract

Aeolian deposits from the Hulun Buir Desert of northeastern China are studied with optically stimulated luminescence dating methods to establish the chronology of dune building phases and climatic changes since the last deglaciation. Our results indicate that wet climate, marked by dune stabilization and soil development in the Hulun Buir Desert, commenced at-11 ka ago, and this early episode of dune stabilization lasted until 4.4 ka ago. This optimum climate between -11 and -4.4 ka ago is mostly the response to the strengthened monsoon circulation and increased precipitation in the Northern Hemisphere. The environment generally became arid after - 4.4 ka ago, but the dry climate was interrupted by three phases of weak soil development occurring at - 1.8-1.4, - 1.2-1.0 and - 0.84-0.5 ka ago, respectively. Such short events of dune stabilization were associated with the warm and humid climate in historical time. However, the present dune mobilization in the Hulun Buir Desert is mainly the result of poor land-use practices (land cultivation and overgrazing) since about 300 years ago.