Researches About The Lakes' Development And Palaeoclimate Changes In The Area Of Cuoqin Of North Tibetan Plateau

The global change is one of nowadays important issues that the whole mankind faces, especially climatic change caused the great attention of people and scientists. The thesis is based on the new round of regional geological survey of 1:250000, has fully absorbed forefathers' research data and achievement in this area. The paper adopted multi-disciplinary theories and methods that cross sedimentology, remote sensing geology, Quaternary geology , mineralogy , isotope geochemistry , element geochemistry , paleontology , geomorphology ,etc. We have summarized the evolve of lakes and palaeoclimate changes,in Cuoqin in depth, scientifically and systematically and predicted scientifically to this area future evolution trend and climate changes trend of lake.In the middle and later period of the Pleistocene, an ancient lake developed in the area ofCuoqin------Lanong ancient lake. In the end of Pleistocene, because of the last function tectonicmovement and the corrosion of river, the lakes withers away . During the high lake period of the later pleistocence ,on the whole north plateau of Tibet developed a big ancient lake ---- ancient lake of Qiangtang . In the later period of the pleistocence, ancient lake of Qiangtang shrunk and disintegrated gradually. There are two mainly ancient lakes in the area of Cuoqin---- ancient taruocuo and ancient zharinanmucuo. As the palaeoclimate is developed overallly toward aridity during the Quaternary Period, two ancient lakes shrunk and disintegrated further. Zhabuyechaka was separated from the ancient taruocuo. Since the 36ka BP ,Zhabuyechaka has gone through 4 bigger shrinking stages and 3 bigger expanding stages altogether. During the early of Holocene, this lake turned into Salt lake. in the middle of Holocene, it expanded and desalinized transiently. after that it turned into the Salt lake again. Zharinanmucuo, Garencuo, Dibucuo, Qimaicuo, Taruocuo, Dawacuo, Caijicuo, Qigecuo ,etc, all of which han connected to be a enormous latticed deep lake. During the Late Holocene, the unified big lake ancient zharinanmucuo disjionted into isolated lakes. Zharinanmucuo developed into a salt lake in late Holocene. Zharinanmucuo and Zhabuyechaka have similar development process, at the same time, diversities exist Among them . Zharinanmucuo' development process is latter than Zha bu ye cha ka'.The palaeoclimate of Cuoqin often lies between sugar sea and Namucuo, generally speaking,it is more similar with Namucuo, which corresponds to the three places' geographical position. Qinghai-Tibet Plateau dry and cold climatic change has the characteristics that advance from east to west. The rising grandly in the Qinghai-Tibet Plateau has obvious influence on the climate of Cuoqin and shows the positive correlation in the mass.With the increase of the height of plateau, the climate of Cuoqin is overallly tended to warmth and aridity. In the future, the climate of this area will develop to be warm and aridity in the mass. It will turn to the moist trend in a short time. Lakes will expand lightly and continue to shrink as a whole.