BEIJING, Sept. 28, 2023 /PRNewswire/ — Mountains play a significant role in regulating global climate. Therefore, the formation of mountain ranges is of great interest to scientists. The Tibetan Plateau is usually thought to have been formed by the collision between the Indian and Eurasian plates. But this claim is controversial owing to a lack of unaltered terrestrial sediments required for estimating the past elevation of the Tibetan Plateau through paleoaltimetry techniques.
Now, a groundbreaking study, led by Professor Chengshan Wang from the School of Earth Sciences and Resources at China University of Geosciences, has employed an innovative approach to paleoaltimetry to obtain remarkable insights into the formation of the Tibetan Plateau. The work was published in the journal Nature Geosciences on 10 August 2023.
The study used 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 technique: “Oxygen exists as three stable isotopes or chemical variants in nature: oxygen 16, 17, and 18. 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 Tibetan Plateau. The findings also underscore the need to reconsider elevation estimates for other mountain ranges around the world, including that of the Andes, Urals, and Rocky Mountains.
The Tibetan Plateau has always fascinated humankind, but this study brings us a step closer to the understanding of its remarkable history.
Title of original paper: High-elevation Tibetan Plateau before India–Eurasia collision recorded by triple oxygen isotopes
Journal: Nature Geoscience
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SOURCE China University of Geosciences, CUGB