Sand-loess System in the Middle Reaches of Yangtze River since Late Interglacial Indicated by Grain Size

Based on the grain size analysis on the sand and loess at 5 profiles of the Dingshang-Taiping section in the middle reaches of the Yangtze River,we discussed the connection of sandy hill and loess in this region.The results are as follows:(1)The loess in Dingshang-Taiping section is obviously different from those of fluvial sediments but is the same as the aeolian sediments in other region,so it is aeolian origin.(2)The gradual transition of deposit is indicated by the gradual transition of the grain size of sand,mud and loess in the section.Combined with the timing sequence data of the sediments in this region,we conclude that the fluvial sediments in the the Yangtze River were eroded by the strong winter monsoon and the coarse particle was deposited at leeward in form of sandy hill since the last interglacial.The fine particle from flood plain of the Yangtze River were transported far away and deposited in form of loess.The sand in sandy hill and loess in leeward of sandy hill is just a sort of synchronous deposit accumulated in our study region.The sandy hill sand and loess deposit makes up the regional sand-loess system in north Jiangxi province,China.