The finalization of the modern drainage pattern of the Tarim Basin: Insights from petrology and detrital zircon geochronology of sediments from Lop Nur

Abstract The Tarim Basin is the largest arid inland-river basin in China. Although drainage patterns of the basin provide crucial information on the hinterland evolution, the basin-wide river network evolution in this arid region is still poorly understood. This contribution uses a detailed study of the petrology and zircon U-Pb geochronology of sediments from Lop Nur to reconstruct the late Quaternary drainage evolution and source-sink relations of the Tarim Basin. Results reveal a relatively constant and stable sediment supply from the Tianshan Mountains until the middle Pleistocene. Negligible contribution from the Pamirs and Kunlun Mountains, suggests coeval rivers draining the western basin were likely in a premature state with limited propagation toward the basin interior, despite Lop Nur as the rivers’ terminus of the Tarim Basin. This suggested drainage pattern is different from that observed in the historical past or today with rivers draining the western basin crossing the Taklamakan Desert and reaching Lop Nur either after converging into the Tarim River or following separate courses. Combined with reported modern river sediments, ages of river terraces, stratigraphic records and palaeoenvironmental inferences, we tentatively suggest that the modern drainage pattern of the Tarim Basin was likely finalized in the late early Pleistocene or even afterward. Therefore, the ranges along the western Tarim Basin must have experienced fast and strong erosion since the late early Pleistocene that resulted in the steep topography and deep incision of these rivers. Subsequent transport of large quantities of sediment materials into the basin formed the vast and thick deposits of the Taklamakan Desert in a relatively short period of time.