No significant provenance changes in the Hoh Xil Basin, central-northern Tibetan Plateau, from the Late Cretaceous to the Early Miocene

Abstract

The construction and uplift of the Tibetan Plateau has played a critical role in Cenozoic global climatic cooling due to extensive chemical weathering and establishment of the Asian monsoons. However, the models, mechanisms, and timing of Tibet's uplift remain rigorously debated. Important outstanding questions include what were surface elevations of the Tibetan Plateau prior to the Paleogene India-Asia collision and what mechanisms were responsible for the Cenozoic uplift of the central Tibetan Plateau. In this study, we integrated new detrital zircon data from the Tuotuohe Basin, a sub-basin of the Hoh Xil Basin in the central Tibetan Plateau, with paleocurrent directions, petrological textures, sedimentary facies, and eastern and western Hoh Xil Basin isotopes to investigate the source-to-sink relationship between the Tanggula Range and the Hoh Xil Basin. Any notable provenance shifts would have implications for the topographic evolution of the central and northern Tibet and proposed plateau uplift mechanisms. Our detrital zircon data from the Tuotuohe sub-basin revealed no provenance changes between ca. 37 and ca. 20 Ma. Detrital zircon data from the Tuotuohe section and the eastern and western Hoh Xil Basins, paleocurrent directions, petrologic analysis, strata characteristics, and isotopic evidence suggest that there was a single expansive Hoh Xil Basin from the Late Cretaceous to the Early Miocene. Furthermore, the Tanggula Range has been the primary source region for the Hoh Xil Basin since the Late Cretaceous. However, the Fenghuo Range may have provided a significant secondary source of detritus starting in the Late Oligocene-Early Miocene. Our results imply that there was established topographic relief in central-northern Tibet between mountainous highlands in the south and the Hoh Xil Basin in the north since the Late Cretaceous. The Tanggula Range-Hoh Xil Basin experienced surface deformation and uplift from the Late Cretaceous to ca. 40 Ma, induced by the Lhasa-Qiangtang and India-Asia collisions, after which the deformation intensity ceased by ca. 27–24 Ma. Therefore, the additional ∼1.5 km surface uplift of the Hoh Xil Basin since the Middle Miocene cannot be the result of crustal shortening. Instead, surface uplift may have been caused by the convective removal of the mantle lithosphere or magmatic inflation, which explains the sub-horizontal attitudes of the Middle Miocene Wudaoliang Formation in the region.