策勒绿洲与荒漠交错带达木沟剖面地化元素分布与古气候

策勒绿洲与荒漠交错带的达木沟剖面地化元素的分布及古气候意义的研究表明，虽然近四千来来气候的干旱状况持续未变，但其间仍有若干次相对湿润与干旱化加剧的波动。以２００ａＢＰ为界，其前以相对湿润为主，而其后则以持续干旱为主要特征，且存在三次干旱化程度加剧时期，即１５００ａＢＰ，１２００ａＢＰ和１０００ａＢＰ。

THE DISTRIBUTION OF GEOCHEMICAL ELEMENTS AND ITS PALEOCLIMATIC SIGNIFICANCE IN DAMUGOU SECTION IN THE OASIS-DESERT TRANSITIONAL BELT, CELE, SOUTHERN XINJIANG SINCE ABOUT 4000a B.P

Located in the southern part of Xinjiang Uygur Autonomous Region, Cele County is a typical oasis in the southern margin of the Taklamakan Desert. The annual precipitation, evaporation and air temperature are 34mm, 2 595. 3mm and 11. gi respectively. The scope of Cele oasis changed greatly since the late Quaternary. This change process itself contained a lot of information of the environmental evolution, and was sensitively recorded by the different geologic bodies in the transitional belt between the Cele oasis and desert. This paper discusses the distribution of geochemical elements in Damugou section which locates in Cele oasis-desert transitional belt. The results show that since about 4000a BP, although the dry regime already existed, there were still several fluctuations of relative wet periods and dry-aggravated periods. Combining with the chronological and sedimentary studies, before about 2000aB. P., climate was dominated dy relative wet, but then it was characterized by consecutive drought with three intense desertification periods, i. e. since about 1500aB. P., the climatic characteristics were similar to that in modern times in this area. At about 1200aB. P. and 1000aB. P., the fringe desertification in Cele oasis tended to aggravation again. Especially since 1000aB. P., the modern environmental features in this area have formed, and coincided with the study resluts obtained from the other ditricts in China. This study shows clearly that climate tended consecutively to dry, and aggravated lately.