Regional classification and developing trend of desertification in Northern China

From the geologic point of view,land desertification in Northern China is mainly controlled by geologic backg rounds suchas tectonic-sedimentary characteristics,hydrogeologic conditions,global climatic changes,especially the mon soon currentin East Asia,which were formed since the a scent of the Qinghai-Tibet plateau.The regional classification and distribution,formation process and developing trends of sandy and watereroding desertification a rediscu ssed mainly in this paper.Sandy desertification in Northern China could bedivided in to three types,the localized type,the windblown type and the coarsegrained type. Localized sandy desertification is mainly dist ributed in northwest in land basins and alluvial fans a round them,in marginal area saround deserts,in paleo-river channels which flew through deserts,in areas in which fluviatile and lacustrine sandy sedimenta ries are widely spread,and in the areas in which soils are developed on sandy sedimentary materials as well. The windblown type is distributed mainly in the leeward areas at the edge of deserts,such as the south rimdistricts of Badanjilin desert and Tenggerli deserts,sand-covered loess areas at the south of Mu Us Shadi desert,Horqin Shadi and the Liaohe plain.Coarsegra in type desertification is distributed mainly in the transitional areas of deserts and gobi,in sandy grass-land in middle and east plateaus.