Upward and outward growth of north-central Tibet: Mechanisms that build high-elevation, low-relief plateaus.

Abstract

Large orogenic plateaus, such as the Tibetan Plateau, are characterized by high-elevation, low-relief topography, in contrast to the rugged terrains of narrower mountain belts. A key question is how low-elevation hinterland basins, characteristic of broad regions of shortening, were raised while regional relief was flattened. This study uses the Hoh Xil Basin in north-central Tibet as an analogue for late-stage orogenic plateau formation. The precipitation temperatures of lacustrine carbonates deposited between ~19 and ~12 million years ago record an early to middle Miocene phase of surface uplift of 1.0 ± 0.7 km. The results of this study demonstrate the contribution of sub-surface geodynamic processes in driving regional surface uplift and redistribution of crustal material to flatten plateau surfaces during the late stage of orogenic plateau formation.