Climatic And Environmental Evolution During72.4～51.0Ka B.P.in The Northwest Of Lop Nur

Lop Nur is located in the southeast of Xinjiang, China.lt is one of the driest places in the world. The environmental change in Lop Nur is the representative of the ancient climate and environment change of the mountainous region of Tarim Basin and its surroundings. Therefore, research on climate and environment change in this area is very valuable for researches on Global Change, ecological environment preservation and resources development and utilization of the drought desert area, and realistic for siting great construction projects with long-term safety evaluation during construction and after-construction.This article studied the LX02section on the north bank of Kongque River located on the northwest of the Lop Nur, based on the OSL of sediments of section, With the help of statistical methods72.4～51.0ka B.P. climate and environment change sequence on the northwest edge of the Lop Nur is established, according to the analysis and judgment of granularity, chroma, clay minerals, carbonate, geochemical elements and pollen of the sediment of the Late Pleistocene epoch, and the regional climate response to the global change is discussed. The following conclusions are developed:The whole change sequences can be classified as three stages according to each environmental index changing with time:72.4～66.8ka B.P. was a cold-arid period, and the trend became stronger with the time;66.8～56.1ka B.P. was a warm-humid period with small amplitude climatic fluctuations;56.1～51.0ka B.P. was a cold-arid period, though obviously weaker than in the period of72.4～66.8ka B.P. with a tend to another warm-humid period.The characteristics of hydrothermal allocation in the climate change in the northwest of the Lop Nur are different from those in the west westerlies, but similar with the monsoon climate mode, i.e., moist in warm period, and draught in cold period.The PCA (principal component analysis) is used for extracting the comprehensive information, such as global chemical elements index and indexes of granularity, chroma and carbonate.The average value of the first principal component (F1and F1’)in each stage is defined as warm and moisture index. Combined with B.T.P./(S.P.+H.P.) and the contents of the pine and oak pollens in sporopollen index, and compared with the change sequence of the oxygen isotopes of Guliya ice cores, as well as Greenland Highland and change sequence of radiant quantity of the sun at the northern latitude65°, it is initially determined that the climate and environment change progress in the area during the period of72.4～51.0ka B.P. had been restricted by the global change. However, the degree of change was related with the environmental factors in this region.Based on the comprehensive study of high resolution and multi environmental index, the waves of cold and warm, dry and moist and the climate change mode in the area of the northwest edge of the Lop Nur in the period of72.4～51.0kaB.P. are shown. The establishment of the environment change sequence makes the achievement of the climate and environment change study of the middle of the late Pleistocene of the Lop Nur, which provides a reliable basis for forecasting in this area the extreme climate conditions and unexpected environmental events that may occur in future hundreds and thousands of years.