Keywords: 
• dry-lake sediments /
• grain-size analysis /
• sand-dust weather in East Asia /
• Northwest of China

Abstract: Some dry lakes widely distributed in the north of China has been investigated in this paper based on analysis of grain-size distribution of the sediments of these dry lakes, including Manas Lake in Junggar Basin, Juyan Lake in the Alxa Plateau, Yezhu Lake in Minqin Basin and so on. The analyzed results are as followed: the total volume-percentage of the particles (10 μm) of dry lake-bed surface sediments is above 60%. There are plenty of clay particles (10 μm) on the surface of sandy grassland developed from dry lake-bed and the content amount to about 50%. The tiny particles on the surface of abandoned land can be blown away easily and rapidly, so the content of clay particles in Minqin Basin is less than 13.9%. The grain-size distribution of active dune in northwest of China is the fewness of particles (63 μm) and very little of the particles(10 μm). Frequently, sands of active dune in northwest desert areas have weak influence on North China and East China. It is considered that although the weather of sand-dust storm, blowing-sand and suspending-dust occur originally in the western desert, sandy areas of the Alxa Plateau, the north of Hexi Corridor and the east, center of Mongolia, it is the sand-dust materials(63μm),especially those dust(10μm) really influence North China and East China for limitation of transportation distance and height of coarse particles. It is concluded that material sources that influence the sand-dust weather of East Asia are not only inland deserts, more importantly, but also the dry lake, abandoned land and bare sand-gravel grassland.