摘要
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<20μm 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 Mountains and 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.
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 Mountains and 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.
基金
supported by the National Natural Science Foundation of China (No.41262007)
the Collaborative Innovation Center for Major Ecological Security Issues of Jiangxi Province and Monitoring Implementation (No.JXS-EW-00)
the Innovation Fund Designated for Graduate Students of Jiangxi Normal University(YJS2018069)
the Foundation of Jiangxi Educational Committee (No.8884)
the Opening Fund of Key Laboratory of Poyang Lake Wetland and Watershed Research(Jiangxi Normal University),Ministry of Education (PK2018004)
