Grain size characteristics and genesis of the Muxing loess in the Muling- Xingkai Plain,Northeast China

摘要

Thick loess is deposited on the platform in the piedmont zone of Muling-Xingkai Plain(Muxing Plain),but the genesis of the Muxing loess is still unclear.The aims of this study are to analyze the grain size characteristics of Muxing loess collected from the cores of a typical borehole(ZK1)in the piedmont zone of Muxing Plain,and to verify its genesis.The Muxing loess is mainly composed of the particles with diameter less than 50μm,with an average content of 92.48%.The coarse silt particles with diameter of 10-50μm are the basic composition of aeolian sediments,and their average content is 44.34% for the Muxing loess,which is the mode class among the particles with different diameters.The grain size parameters and frequency curves are similar to those of the typical aeolian sediments.The distribution characteristic of the Muxing loess in the C-M scatter diagram is consistent with that of the Xi Feng loess.In addition,the discriminant analysis shows the Muxing loess mostly consists of aeolian sediments.Therefore,it can be concluded that the Muxing loess mainly resulted from aeolian deposition based on the grain size characteristics.Muxing Plain is dominated by the monsoon climate,and the wind-blown dusts are gradually deposited after being transported over long distances.