Pleistocene northward thrusting of the Danghe Nanshan: Implications for the growth of the Qilian Shan, northeastern Tibetan Plateau

Abstract

Understanding the tectonic history of the Qilian Shan provides significant insights into the growth pattern of the northern Tibetan Plateau. Due to the limitation of methodology and lack of detailed geological information over remote mountain ranges, there has been less information on the Pleistocene evolution of the southern Qilian Shan. Existing models for the Qilian Shan growth also fail to specify whether the southern Qilian Shan grew northward or southward during the late Cenozoic. Here we present provenance data on fieldwork paleocurrents, petrography, heavy mineral analysis, and zircon UPb ages from the Danghe valley between Danghe Nanshan and Yema Nanshan, southern Qilian Shan. Results show a ‘seesaw-like’ change of provenance from Yema Nanshan to the north during the early Pleistocene to Danghe Nanshan to the south, which suggests the northward thrusting of Danghe Nanshan. Integrated with previous studies, our inference of a Quaternary rapid exhumation of the southern Qilian Shan reinforces the argument of northward propagation of the southern Qilian Shan during the Pleistocene and suggests a complex growth pattern of the Qilian Shan, northeastern Tibetan Plateau.