Distribution Of U-Pb Ages Of The Detrital Zircon From The Hobq Desert And Its Implications For Provenance

The provenance of the Hobq Desert is still under great debates with views ranging from erosion of surrounding mountains to desertification of local bed rocks,and to material supply from Yellow River.The U-Pb age of detrital zircon is a powerful tool for source tracing.The study,with helps from field investigation,tries to resolve the material source of Hobq Desert by comparing zircon U-Pb age population of the desert sands of different location and their potential source materials.Totally 900 zircon grain of nine samples,include beach sand of Hetao paleo-lake,exposed bedrock desert,sands of modern sand duns,fluvial sand in the channel of Yellow River and its local tributaries,were analyzed.The ages of the paleo-lake sediment were also determined by OSL Dating.The results show that zircon U-Pb ages of the Hobq desert are mainly distributed around 2.5Ga,1.9Ga,960Ma,450Ma and 280Ma.The zircon age distribution show clear spatial pattern.which reflect decreasing eastward contribution of Yellow River and thus increasing contribution of local material.The Hetao paleo-lake may have played an important role collecting the local material and Yellow River contribution.which indirectly contribute the mixed material to the eastern Hobq Deset after its mobilization.Through further comparison with the potential source region,the main sources of west and central desert maybe the northern Tibet,local paleolake rework sand dominate in the east of the desert.