Aeolian Sand Deposition in the Source area of yellow River and its Sgnificance

Key words: 
• source area of Yellow River /
• sand dune /
• sedimentary characteristic /
• dusts

Abstract: We found a vast area of modern and paleo-sand dunes and desertifized grassland in the source area ofYellow River on the northeastern Qinghai-Xizang (Tibet) Plateau. Remote sensing，geomorphological , sedi-mentological and chronological analyses have demonstrated that these sand dunes are locally formed semi-ma-tured dunes characterized by coarse and moderately sorted grains and a majority of semi-matured aeoliansands. They are formed mainly in four periods, i. e.，the late penultimate glacial，last glacial maximun，coldepisodes of the Holocene , and present day. The distribution of sand dunes and the aeolian maturity of sandsincrease significantly with time，suggesting an intensified air circulation，with which tremendous dusts weretransported to loess deposition areas on the eastern front of the Qinghai-Xizang Plateau and its adjacentdownwind area.