Different provenance of separate loess sites in Yangtze River Basin and its paleoenvironmental implications Different provenance of separate loess sites in Yangtze River Basin and its paleoenvironmental implications

最小化 最大化

Vol16 No.7: 1616-1628

Title】Different provenance of separate loess sites in Yangtze River Basin and its paleoenvironmental implications

Author】ZHANG Zhi1,2; JIA Yu-lian1*

Addresses】1 School of Geography and Environment, Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, Nanchang 330022,China; 2 College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, China

Corresponding author】JIA Yu-lian

Citation】Zhang Z, Jia YL (2019) Different provenance of separate loess sites in Yangtze River Basin and its paleoenvironmental implications. Journal of Mountain Science 16(7). https://doi.org/10.1007/s11629-018-5278-6

DOI】https://doi.org/10.1007/s11629-018-5278-6

Abstract】The dust deposits in the Yangtze River Basin (YRB) have been widely distributed along the Yangtze River valley. Previous studies mainly concentrated in its provenance of each loess site, however, the differences in provenance of loess among different sites in this area have rarely been studied. Here, the geochemical characteristics of the <20 μm fraction in the loess in separate Jiujiang, Xuancheng and Nanjing sites were analyzed. The result shows that the loess in Jiujiang and Nanjing sites, near Yangtze River riverway, share similar geochemical characteristics that may commonly derived from the detrital materials of Yangtze River. However, both sites have significantly different elemental compositions compared with Xuancheng site, which is ~60 km away from the Yangtze River riverway. These sites share different geochemical characteristics with Eastern Qinling Mountainsand Xifeng section on the Chinese Loess Plateau, North China. Combining the distribution of the aeolian sand hills and the loess in this area published by previous studies, we suggest that the exposed river valley floodplain caused by weak summer monsoon provided abundant materials to form local dust cells controlled by strong winter monsoon during the glacial periods. Therefore, those local loess deposits should be identified as the “valley-sourced loess”. These reveal the inherent connection between the monsoon system and the loess deposits in Yangtze River Basin.

Keywords】Yangtze River Basin; Geochemistry; Loess provenance; Valley-sourced loess; Loess Plateau