Propagating uplift controls on high-elevation, low-relief landscape formation in Southeast Tibetan Plateau - Archive ouverte HAL Access content directly
Conference Poster Year : 2021

Propagating uplift controls on high-elevation, low-relief landscape formation in Southeast Tibetan Plateau

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Abstract

High-elevation, low-relief surfaces are widespread in many mountain belts. However, the origin of these surfaces has long been debated. In particular, the Southeast (SE) Tibetan Plateau has extensive low-relief surfaces perched above deep valleys and in the headwaters of three of the world’s largest rivers (Salween, Mekong and Yangtze). Synthesized low-temperature thermochronologic data indicate that uplift of the Tibetan Plateau may have propagated progressively from NW to SE, with thermochronologic ages at ~50 Ma observed in the headwaters and interfluves of the rivers but young ages <10 Ma measured in deep valleys. Various geologic data and geodynamic models also show that many mountain belts grow first to a certain height and then laterally in an outward propagation sequence. By translating this information into a kinematic propagating uplift function in a landscape evolution model, we propose that the high-elevation, low-relief surfaces in the SE Tibetan Plateau are simply a consequence of mountain growth and do not require a special process to form. The propagating uplift forms an elongated river network geometry with broad high-elevation, low-relief headwaters and interfluves that persist for tens of millions of years, consistent with the observed geochronology. We suggest that the low-relief interfluves can be long-lived because they are lack of drainage network to keep pace with rapid incision of the large mainstem rivers. Our results reproduce the observed co-planarity of these low-relief surfaces, their height 2-3-km above adjacent valleys, as well as their progressive decrease in elevation from NW to SE across the plateau margin. The propagating uplift also produces spatial and temporal exhumation patterns and river profile morphologies that match observations. Our modeling therefore reconciles geomorphic observations with geodynamic models of uplift of the SE Tibetan Plateau, and provides a simple mechanism to explain low-relief surfaces observed in several mountain belts on Earth.
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Dates and versions

insu-03532446 , version 1 (18-01-2022)

Identifiers

  • HAL Id : insu-03532446 , version 1

Cite

Yuan Xiaoping, Kimberly Huppert, Jean Braun, Xiaoming Cheng, Liu Jing, et al.. Propagating uplift controls on high-elevation, low-relief landscape formation in Southeast Tibetan Plateau. American Geophysical Union Fall Meeting (AGU 2021), Dec 2021, virtual, United States. pp.EP15F-1380, 2021. ⟨insu-03532446⟩
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