Using analyses on zircons’ (a silicate mineral, ZrSiO4, chemically stable) U-Pb ages, paleocurrent directions, and sandstone composition preserved in detrital sediments with reliable chronology, also combined with the calculation of the contribution of a mixture of sources, a research team from Institute of Earth Environment of the Chinese Academy of Sciences (CAS) have reconstructed the provenance history of the Hoh Xil Basin, central-northern Tibetan Plateau, from the Late Cretaceous to the Early Miocene.
They found that from the Late Cretaceous to the Early Miocene, the detrital zircons age spectra, paleocurrent directions and sandstone compositions of the Hoh Xil Basin did not change evidently, implying that its source did not undergo significant changes during this time period. Calculation of the source contribution indicates that the Late Cretaceous to the Early Miocene source area of the Hoh Xil Basin was mainly the Tanggula Mountains, which are located in the southern part of the present basin.
"This new paper suggests that the basins and ranges landform in the north-central Tibetan Plateau was formed at least as early as the Late Cretaceous, and that the collision of the Indian and Eurasian plates around 55 Ma may have made this geomorphic pattern even more remarkable," Dr. Li said. "One of the distinctive features of the present-day Tibetan Plateau is the very flat plateau surface, so an important and interesting question should be when and how the previously distinctive basins and ranges relief was developed to the present flat plateau surface," Dr. Chang added.
Contact: BAI Jie, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China. Email: baijie@ieecas.cn