The origin and provenance of Malan loess along the eastern margin of Qinghai-Xizang(Tibetan)Plateau and its adjacent area

A preliminary study of the Malan loess on the eastern margin of the Qinghai-Xizang (Tibetan)Plateau and its adjacent area shows that along the boundary of Kunlun Mts.-Buqing Mts.-A'nymaqn Mts.-South Qinling(Motianling),the Malun loess falls roughly into two main depositional regions:to its north,a hot loess region in which dusts come mainly from the Asian inland arid area;to its south,a cold loess region in which dusts come chiefly from the Qinghai-Xizang Plateau.The possible causative fac- tors and processes for the loess difference are the uplift of the Plateau and the effects of its resultant particuo lar landform,the interactions of its induced Asian monsoon,by-flowing westlies and plateau monsoon,and the difference of sediments of source areas.