关键词: 新疆, 黄土分布, 粉尘来源

Abstract: The loess cover of Xinjiang is one part of the loess belt in China.Based on the differences of regional landform,sedimentary feature and material components of Xinjiang loess(mineral,grain size and contents of CaCO₃),it can be divided into three subregions,namely the Northern Subregion,Southern Subregion and Western Subregion.The results studying on local topographic condition,the regional atmospheric motion and the transportation and depositional processes of dust show that the loess in different subregions of Xinjiang has various sources.It was affected by general atmospheric circulation on several scales and related to the weather processes of dust sources.The Southern Subregion is located at the south of Tianshan Mountains.The loess cover is mainly widespread along the northern slope of Kunlun Mountains.The sediments accumulated in Tarim Basin and Taklimakan Desert supported plentiful silts for the loess formation of this subregion since 880 ka BP.In the northern part of Tianshan Mountains,namely the Northern subregion,the loess cover lies at the foot of the West Mountains and northern slope of Tianshan mountains.The dust to form the loess mainly comes from the desert of Junggar Basin.According the TL dating,the loess had been accumulated since 285 ka BP.The Western Subregion is situated at the Yili area and belongs to an intermountane basin of Tianshan Mountain.The loess distributes along the steppe and desert steppe and was mainly accumulated during the Late Pleistocene.The westerly circulation is accounted for the transportation of dust and Central Asia Deserts is the main source of loess materials of this region.

Key words: Xinjiang, loess distribution, dust source