Compositional variation of Cenozoic detritus in the Lulehe area, Qaidam Basin, and its implications for Tibetan Plateau tectonic uplift

The change of detrital composition is a typical manifestation of the evolutionary process of sedimentary sources.As an im-portant part of the Qaidam Basin, the sedimentary strata in Lulehe have recorded tectonic uplift evolution of northern Tibetan since the Indo-Asian collision.All signatures, along with high feldspar content, provenance and contrast with adjacent mountain rocks, re-veal that the source region for Lulehe mainly came from Qilian and Saibei thrust.And there existed a coupling relationship between the change of clastic composition content and surrounding orogen.Three significant depositing transformation events occurred in Lu-lehe area, corresponding to the Indo-Asian collision and plateau tectonic uplift from Cenozoic in 53.5~2.9 Ma.The rapid uplift of southern Qilian, which happened at ca.50.1~46.6 Ma, responded to the propagation of initial continental collision.The uplift of Ti-betan Plateau with crustal vertical growth and thrust structure caused top erosion of Saibei thrust and provenance transformation event in Lulehe in Eocene (44.5 Ma).Both of Saishiteng and Qilian Mountain supplied sediments at the end of Oligocene (22.6 Ma) when different regions in plateau were raised synchronously.The findings will provide new crucial sedimentary data for deep under-standing of evolutionary history of whole Tibetan Plateau and distant effect of the continental collision.