黄河源风沙沉积及意义

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

考察发现黄河源发育有广泛的现代、古代风沙沉积和沙漠化草地。地貌、沉积和年代学的分析表明，这些沙丘都是就地形成的半成熟沙丘，粒度粗，分选中等，形成于四个主要时期，即倒数第二次冰期末、末次冰期最盛期，全新世寒冷时期和现代，为青藏高原及邻区黄土提供了丰富的粉尘。

We found a vast area of modern and paleo-sand dunes and desertifized grassland in the source area of mentological and chronological analyses have demonstrated that these sand dunes are locally formed semi-matured dunes characterized by coarse and moderately sorted grains and a majority of semi-matured aeolian sands. They are formed mainly in four periods, i. e., the late penultimate glacial, last glacial maximun, cold episodes of the Holocene, and present day. The distribution of sand dunes and the aeolian maturity of sands increase significantly with time, suggesting an intensified air circulation, with which tremendous dusts were transported to loess deposition areas on the eastern front of the Qinghai-Xizang Plateau and its adjacent downwind area.