Present-day uplift of the East Kunlun Shan, Northern Tibetan Plateau

Abstract

<p>Part of the 5-km high Tibetan plateau is undergoing eastward extension and crustal thinning, which might be the signature of a waning orogeny. However, the actual extent of such processes throughout the high plateau remains uncertain. Here, we examine the impact of tectonic, geodynamic, and climate-related surface processes on the vertical deformation monitored since 2007 by continuous Global Positioning System (GPS) across the East Kunlun Shan (EKS), the largest relief inside the Tibetan plateau. GPS measurements reveal 1-2 mm/yr uplift of the EKS relative to the 2-km-lower Qaidam Basin. However, the range-perpendicular shortening is limited at most to ~1 mm/yr, which is not adequate to drive the observed vertical motion. Instead, (1) the isostatic response to erosion and regional deglaciation since the last glacial period likely accounts for a significant fraction, up to 40%, of our GPS derived vertical rate, and (2) the EKS and its surrounding region to the south are probably still rising at ~1 mm/yr, rather than subsiding. Thus, our results show that this part of the northern Tibetan plateau is rising, demonstrating that the Tibetan Plateau is still actively growing, in contrast with previous models proposing the passive demise of the high plateau due to erosion and gravitational collapse.</p>