Paleoenvironmental Records In Aertashi Section In The Southwestern Margin Of The Tarim Basin

The aridification of the Asian continental interior is one of the important research problems about Cenozoic environmental studies. Aertashi section is a pretty good section in the southwestern margin of the Tarim Basin, which is able to provide us with new and direct evidence about uplift of Tibetan plateau, regression of Paratethys and the aridification of the Asian continental interior, owing to its special location, controlled by westerlies, adjacent with northern margin of the Tibetan plateau, along the West Kunlun Shan and South Tian Shan. This study reports Lithostratigraphy, Chronology and Geological records of Aertashi section, and analyses paleoclimate and paleoenvironmental evolution with the results of particle size, magnetic susceptibility and sedimental color, and tries to explain uplift of Tibetan plateau and the aridification of the Asian continental interior.The following points mark the main conclusions of this thesis:1. In the framework of age, lithological catastrophe and different sedimentary facies are consistent with three large tectonic events:Early Himalayan Movement at late Eocene and twice uplifts of the Tibetan plateau with different amplitude at late Miocene and Pliocene.2. The change of grain size of sedimentation indicates the northward uplift of the Tibetan-Pamirs plateau.3. Cenozoic sediment grain size was maximal at Pliocene, indicating a strong uplift of the Tibetan plateau at Pliocene.4. The whole different experience of sedimental color from Paleocene to Pliocene shows that the climate at Cenozoic at northwest of China has been turning cold gradually.5. Increasing trends of magnetic susceptibility indicates dry and cold weather at northwest of China.6. Gypsum deposition in the sediments, lithological description and paleontological resources show the arid environment during Cenozoic.