Study on Grain-size of the Aeolian Sediments in the Northern Fringe of Xiangshan Mountain During the Last Glacial

Grain size is the most fundamental property of sediment particles,affecting their entrainment,transport and deposition.The aeolian sand and dust has been taken as an important proxy of expansion and contraction of the desert during geological period.The signals of the desert evolution were well preserved in the aeolian deposits on the margin of the desert,which are effective to reconstruct the desert expansion and contraction.According to the dominant wind direction,generally NW-SE,the authors systematically studied 7 sections of Malan loess in the Northern fringe of Xiangshan Mountain during the Last Glacial period.Detailed granular analyses show the properties of temporal and spatial of the Malan loess,and reducing of the percentage of the sand from northwest to southeast.The study indicates a new linear correlation model of sand percentage with altitude and distance,and the altitude has a more influence to the sand fraction.