Sedimentary and OSL dating evidence for the development of the present Hobq desert landscape, northern China

The sedimentary sequence and landscape of the Hobq desert was observed through twelve profiles along five N-S sections extending through the entire desert.Aeolian sands were found to overlie the alluvial,diluvial,and lacustrine sediments in this desert.Optically stimulated luminescence(OSL)dating results were obtained from post-IR OSL signals of quartz fractions of sand samples at the bottom of sand dunes and hills by using the Double-SAR protocol.The OSL ages reveal that the latest sand accumulation began around 19 ka in the northwestern part and 9 ka in the eastern part of the Hobq Desert.Around 7 ka,the sand accumulation was strengthened and extended southward and northward 2 ka to develop the present desert landscape.Our study suggests that the aeolian sand accumulation around 19,9 and 7 ka resulted from the weakening of the Asian summer monsoon over this region.However,the rapid development of the present Hobq desert landscape since 2 ka was likely triggered by human activities in this desert.