Paleogene topography of the northern Tibetan plateau: insights from flexural modeling

Abstract:

Understanding the Paleogene topography of the Tibetan plateau has vital implications for the growth of the entire plateau and climate evolution in Asian during the Cenozoic. Yet, the Paleogene topography along the northern edge of the Tibetan plateau remains ambiguous. In this study, we conducted flexural modeling to estimate the topographic load of the Qilian Shan and Eastern Kunlun Shan using the Paleogene isopach data obtained from the Qaidam basin. Our modeling results reveal a greater topography load in the Qilian Shan region to the north comparing with the low topography load in the Eastern Kunlun Shan to the south. This finding indicates a relative high relief in the Qilian Shan and a low relief in the Eastern Kunlun Shan in the Early Cenozoic. Taking a previous proposal of low Paleogene elevation of the Qaidam basin into account, we infer that the relative high topography has been established in the northern Tibetan plateau, shortly after the India-Asian collision during the Early Cenozoic. Given that the Eastern Kunlun Shan and Qilian Shan share a similar mean elevation, our results might further suggest the pulsed and out-of sequence deformation in the northern Tibetan plateau during the Neogene.