OSL chronology of sand deposits and climate change of last 18ka in Gurbantunggut Desert, northwest China

Abstract

The development of the Gurbantunggut Desert is mainly controlled by the Westerly wind, and at present has little influence from Indian and Southeast Asian monsoons. A combined study using optically stimulated luminescence (OSL) dating, ground-penetrating radar (GPR) surveys and climatic proxies analysis was carried out in the southern part of the desert. The chronology extends back to 18ka and is constructed based on 16 OSL ages from boreholes in the linear dune body and the inter-dune area. The chronology suggests that sand deposition in the last 18ka experienced two rapid accumulation phases at 11 and 2.5ka ago which were also evident from the GPR surveys. These periods relate to increased aridity in the region. Five climate phases are identified from the last 18ka, based on the OSL chronology and climatic proxy analysis with grain size and magnetic susceptibility measurements. The deglacial period (18.3-10.4ka) is characterized by climate instability and possible glacial melting events. The Holocene Optimum peaked 8.5ka and terminated 3.6ka ago, when the regional climate became arid. OSL samples from the dune body cluster around 2.5ka, which indicates rapid advance/extension of dune bodies at this time. © 2011 John Wiley & Sons, Ltd.