【摘要】 对雅鲁藏布江江当宽谷附近地表堆积物的粒度和矿物分析结果表明，沙丘沙的平均粒径、分选性、主粒组构成以及矿物成分与附近沙源物质具有一致性和继承性。河流冲积物是最主要的沙源，其次是洪积物和基岩风化物。河谷沙漠化从根本上就是沙源物质“就地起沙”导致的土地退化过程。同时，沙源物质的差异决定了沙漠化发展速度和性质的复杂性更多还原

【Abstract】 Laboratory analysis results of the land surface sediments from Jiangdang wide valley area of Yarlung Zangbu River reveal that there are chiefly three different kinds of source sediments. Among them, the fluvial deposit consists of the majority, and secondly come the alluvial deposit and weathered bedrock residue. Desertification in this area is fundamentally resulted from soure sediments activation by wind. Meanwhile, the differences of sand soure sediments influence the rate and feature of desertification.更多还原