Coupling between uplift of the Central Asian Orogenic Belt-NE Tibetan Plateau and accumulation of aeolian Red Clay in the inner Asia began at ~7 Ma

Abstract

The Asian interior contains the Central Asian Orogenic Belt (CAOB, the longest accretionary orogen on Earth), the largest mid-latitude desert, and the most widespread late Cenozoic airborne dust deposits (Red Clay) in the Chinese Loess Plateau. This Quaternary loess deposit is underlain by aeolian Red Clay, which has a basal age of ~7 Ma throughout most of the Loess Plateau (except for several sites with latest Oligocene age in its western margin). By integrating the most recent knowledge of the reactivation and uplift history of the CAOB and the northeastern (NE) Tibetan Plateau with the magnetostratigraphic ages of the aeolian Red Clay, we provide evidence for coeval timing between the reactivation of the CAOB-NE Tibetan Plateau and the accumulation of the Red Clay, both of which began at ∼7 Ma. We suggest that the reactivation of the CAOB and the NE Tibetan Plateau played an important role in the deposition of the Red Clay in the latest Miocene-Pliocene through its control of the production of vast amounts of silt-sized debris created by frost weathering and of the transportation by the enhanced strength of the northwesterly wind systems. Detrital zircon ages demonstrate that the source materials of the late Cenozoic Red Clay were mainly derived from a mixed provenance of enlarged alluvial fans coherently linked to the late Cenozoic uplift of the CAOB and the NE Tibetan Plateau. These relations provide the basis for understanding the connections between the deep Earth (lithosphere) and surface processes and their impact on the ecosystem in Asia.