Changing provenance of late Cenozoic sediments in the Jianghan Basin

Abstract

The Yangtze River is one of the most important components of the East Asia river system. In this study, sediments in the Jianghan Basin, middle Yangtze River, were selected for trace element and rare earth element (REE) measurements, in order to decipher information on the change of sediment provenance and evolution of the Yangtze River. According to the elemental variations, the late Cenozoic sediments of the Jianghan Basin could be divided into four parts. During 2.68–2.28 Ma and 1.25–0 Ma, provenance of the sediments was consistent, whereas sediments were derived from variable sources during 2.28–1.25 Ma. Comparison of the elemental compositions between the Pliocene and Quaternary sediments revealed a change in sediment source from a more felsic source area to a more basic source area around the Pliocene–Quaternary boundary. Input from the Emeishan LIP should account for this provenance change. Based on the provenance analysis of sediments in the Jianghan Basin, we infer that the Yangtze River developed into a large river with its drainage basin extended to the Emeishan LIP no later than the Pliocene–Quaternary boundary.