Inversion of Late Miocene uplift history from the transient Daxia River landscape, NE Tibetan Plateau

Abstract

The mechanisms of the upward and outward growth of the Tibetan Plateau are crucial for understanding the geodynamic significance of Cenozoic continental collisions. Northeastern Tibet has been suggested as one of the youngest deforming and uplifting margins surrounding the plateau. The existence of fluvial knickpoints and low-relief topographic surfaces along the Yellow River and its tributaries indicate the transience of the landscape in response to active tectonic uplift. Therefore, the uplift history of the North Eastern Tibetan Plateau (NETP) can be potentially inverted from the disequilibrium channel profiles of the Yellow River and its tributaries. The West Qinling Fault (WQF) is part of the geomorphological and topographic boundaries of the NETP. Its uplift history helps to clarify the deformation history of the Tibetan Plateau. In this study, the focus was on the Daxia River (one of the Yellow River tributaries) to identify the distribution of peneplain surfaces and knickpoints, and to present a linear inversion on the fluvial longitudinal profiles for the relative uplift history of the West Qinling. We obtained a relative uplift history with two pulses of change in the uplift rates at ∼5 and ∼2 Ma. Rates of relative uplift maintained low values during the Late Miocene, then slowly increased from 0.1 to 0.2 mm a −1 after ∼5 Ma and suddenly jumped to 0.3 mm a −1 at ∼2 Ma, consistent with recent findings on the deformation records in the NE Tibetan Plateau. We suggest that (1) the Late Miocene–Pliocene landscape evolution was driven by both tectonics and climate change and (2) inversion of the transient longitudinal channel profiles, if applied, may provide broader insights into the upward and outward growth patterns of the NE Tibetan Plateau. Thematic collection: This article is part of the Mesozoic and Cenozoic tectonics, landscape and climate change collection available at: https://www.lyellcollection.org/topic/collections/mesozoic-and-cenozoic-tectonics-landscape-and-climate-change