Vol15 No.4: 708-721
【Title】Tracing the provenance of aeolian loess in the Yangtze River Delta through zircon U–Pb age and geochemical investigations
【Author】QIAN Peng1；ZHENG Xiang-min2*；CHENG Jun3；HAN Yu-jie1；DONG Yan1；ZHANG Jian-guo1
【Addresses】1 School of Geography, Nantong University, Nantong 226007, China; 2 Department of Geography, East China Normal University, Shanghai 200241, China; 3 School of Geosciences, University of South Florida, Tampa, Florida 33620, USA
【Corresponding author】ZHENG Xiang-min
【Citation】Qin P, Zheng XM, Cheng J, et al. (2018) Tracing the provenance of aeolian loess in the Yangtze River Delta through zircon U–Pb age and geochemical investigations. Journal of Mountain Science 15(4). https://doi.org/10.1007/s11629-017-4437-5
【Abstract】Given the conflicts over the proposed formation mechanisms of Xiashu loess, the question of the provenance of sediments comprising the Xiashu loess in the Yangtze River Delta has not been satisfactorily resolved. In this study, the provenance of aeolian sediments of the Yangtze River Delta, China was examined by applying the detrial zircon U–Pb dating technique, Sr–Nd isotopic and trace element compositional analysis. U-Pb dating analysis was conducted on the Xiashu loess at three locations over the Yangtze River Delta, including Huangnishan (HNS) hill, Shengshan (SS) island and the Xuancheng (XC) area. The Xiashu loess and the sediments of the Yangtze River Valley share considerable similarity in their zircon U-Pb age spectra with the same main age peak and comparable age distribution. By contrast, significant differences in the age spectra, exist between the Xiashu loess and loess deposits of Chinese Loess Plateau. Coarse grains of the Yangtze River Delta loess may have a proximal material source identical to the sediments from the Yangtze River valley. Sr–Nd isotopic values of the Xiashu loess match those from the northern margin of the Tibetan Plateau. Rare earth element ratios independent of grain size illustrate that the values from loess of the Yangtze River Deltamostly overlap with those of CLP (Chinese Loess Plateau) loess. This feature implies that loess from the Yangtze River Delta hasa dominant source of distant material similar as the CLP loess. As such, we conclude that multi-proxy analysis of sediments can shed new light on tracing the provenance of aeolian loess in the Yangtze River Delta.
【Keywords】Aeolian loess; Provenance tracing; Zircon U–Pb age; Geochemistry; Yangtze River Delta