The influence of dry lakebeds, degraded sandy grasslands and abandoned farmland in the arid inlands of northern China on the grain size distribution of East Asian aeolian dust

Dry lakes, degraded sandy grasslands, abandoned farmland and mobile dunes which are widely distributed throughout the arid areas of northern China have been investigated in this work. Gain-size distribution of the surface sediments of Manas lake in Junggar basin, Juyan lake in the Alxa plateau, Zhuye lake in Minqin basin and most deserts (such as Mu Us desert, Otindag desert, Horqin desert and Hulun Buir desert) in China have been analyzed. The results show clay with particle sized < 10 mu m on the surface sediments of dry lakebed and sandy grassland developed from dry lakebed, respectively, account for > 60% and similar to 50% of the total mass. Since the tiny particles on the surface of abandoned farmland are blown away easily and rapidly, the content of clay particles in Minqin basin is < 14%. The grain-size distribution of mobile dunes in northern China mainly consists of particles > 63 mu m and few particles < 10 mu m. Consequently, although sand/dust storms originate primarily in the western deserts, the gobi areas of the Alxa plateau, the north and east of Hexi Corridor and in central Mongolia, the widely distributed dry lakebeds, sandy grasslands and abandoned farmland adjacent to the deserts also contribute to aeolian dusts. Hence, the material sources for sand dust storm in East Asia include inland deserts, but also dry lakes, sandy grasslands and abandoned farmland, which are widely distributed throughout the arid inlands of northern China.