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 Qi nghai-Xizang (Tibetan) Plateau and its adjacent area shows that along the boundary of Kunlun Mts.-Buqing Mts.-A 'nyemaqen Mts.-South Qinling (Motianling), the Malan loess falls roughly into two main depositiona l 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 possibl e causative factors and processes for the loess difference are the upl ift of the Plateau and the effects of its resultant particular landfor m, the interactions of its induced Asian monsoon, by-flowing westlies and plateau monsoon, and the difference of sediments of source areas.