Mountains play a significant role in regulating global climate, controlling local weather, giving rise to a diverse variety of endemic flora and fauna, and altering rain patterns. Therefore, the formation process of mountain ranges is of great interest to scientists. The Tibetan Plateau has long been thought to have formed primarily due to the collision between the Indian and Eurasian tectonic plates. But this claim is steeped in controversy owing to a lack of unaltered terrestrial sediments required for estimating the past elevation of the Tibetan Plateau through paleoaltimetry techniques—methods by which elevations of land surfaces in pre-history are determined.
Now, a groundbreaking study, led by Professor Chengshan Wang from the School of Earth Sciences and Resources at China University of Geosciences (Beijing) (CUGB), has employed an innovative approach to paleoaltimetry to obtain remarkable insights into the formation of the Tibetan Plateau. It was made possible through an international collaboration between researchers from CUGB, Chengdu University of Technology, Xi'an Jiaotong University, Shandong University of Science and Technology, Chinese Academy of Geological Sciences, Brown University, University of California, Berkeley, and Stanford University. Their work was published in the journal Nature Geosciences on 10 August 2023.
The researchers used a technique called triple oxygen analysis to examine the modern meteoric waters with epithermal Ag–Pb–Zn deposit quartz veins from the Palaeocene Gangdese Arc in Southern Tibetan Plateau. Prof. Wang briefly explains the paleoaltimetry technique: "Oxygen exists as three stable isotopes or chemical variants in nature: oxygen 16, 17, and 18, each with a different number of neutrons in their atoms. Since the chemical composition of rainfall changes with altitude, with lighter isotopes of all constituents occurring near the peaks and heavier ones occurring at lower altitudes, the oxygen isotopic makeup of the rocks can shed light on past elevation."
After more than three years of work, the researchers obtained remarkable results. They found that contrary to previous assumptions, the Gangdese Arc, a region in Southern Tibetan Plateau, had already achieved an elevation of approximately 3.5 kilometers or more than 60% of its present height, by 63 to 61 million years ago, well before the continental collision. This finding challenges the established notion that only massive tectonic events could have produced such a significant uplift. "The suggested uplift was probably caused by crustal shortening in response to low-angle subduction of Neo-Tethyan oceanic lithosphere," points out Prof. Wang.
The present study not only reshapes our understanding of the Tibetan Plateau formation but also has far-reaching implications for climate modeling and the study of biodiversity in the region. It will potentially lead to revisions in paleoclimatic models and shed light on the evolution of weather patterns and ecosystems in the Himalayan region. The findings also underscore the need to reconsider elevation estimates for other mountain ranges around the world, such as that of the Andes, the Urals, and the Rocky Mountains.
The Tibetan Plateau has always fascinated humankind, but this study brings us a step closer to the understanding of its remarkable history. Let us hope that future studies harness such cutting-edge techniques to further advance this understanding of Earth's geological history!
***
Reference
DOI: https://doi.org/10.1038/s41561-023-01243-x
Authors: Daniel E. Ibarra1,2, Jingen Dai3, Yuan Gao3,4, Xinghai Lang5, Pengzhen Duan6, Zongjun Gao7, Jiquan Chen3, Katharina Methner8, Lijuan Sha6, Hui Tong7, Xu Han3, Dicheng Zhu3, Yalin Li3, Juxing Tang9, Hai Cheng6, C. Page Chamberlain8, and Chengshan Wang3,4
Affiliations:
1Department of Earth, Environmental and Planetary Sciences and the Institute at Brown for Environment and Society, Brown University
2Department of Earth and Planetary Science, University of California, Berkeley
3School of Earth Sciences and Resources, China University of Geosciences (Beijing)
4State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing)
5College of Earth Science, Chengdu University of Technology
6Institute of Global Environmental Change, Xi'an Jiaotong University
7College of Earth Science and Engineering, Shandong University of Science and Technology
8Department of Geological Sciences, Stanford University
9Institute of Mineral Resources, Chinese Academy of Geological Sciences
About Professor Chengshan Wang
Chengshan Wang is a Professor at the School of Earth Sciences and Resources at China University of Geosciences (Beijing). He is a member of the Chinese Academy of Sciences, and the President of the Executive Committee of the Deep-time Digital Earth (DDE) Big Science Program. His research interests include the Cretaceous paleoenvironment and paleoclimate, tectonic uplift and sedimentary response, and analysis of petroliferous basins. With over 19000 citations, he is a leader in the field of uplift of mountain ranges and has extensively studied the Tibetan Plateau and the Himalayan range. He has received The Li Siguang Geological Science Award and the National Award of Natural Sciences.
