A Tentative Discussion on the Time and the Way of Marine Regression from Tarim Bay during the Cenozoic
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摘要


     The sulfur isotope of eighty-four gypsums or anhydrites was used to mark the transgression-regression cycle and the time of final marine regression from Kuqa Basin during Cenozoic. δ34S curve indicates that there exist two obvious transgression in Middle Paleocene and Middle–Late Eocene, respectively. The final marine regression from Kuqa Basin occurred at the end of Oligocene, which was time-equivalent with the regression from southwest Tarim in Tianshan area, indicating that the retreat of the sea water from Tarim Bay lasted until the end of Oligocene. Based on the regional contrasting study in this paper, the authors sum up the time and the style of the marine regression from Cenozoic Tarim Bay as follows the initial retreat occurred at the beginning of Eocene to the west foot of the Kunlun Mountains; then the retreat moved to Kezi and Aertashi areas at the east foot of the Kunlun Mountains in late Eocene; finally, the retreat migrated to the Tianshan Mountains at the end of Oligocene, which also represents the thorough marine regression from Tarim Bay. This way of marine regression from Tarim further implies that there existed a distant effect caused by India-Asia collision, and the asynchronism of marine regression among different areas in Tarim Basin shows that the transgression-regression cycle of Tarim Bay in Cenzoic was not only controlled by global sea level eustasy but also by some other factors such as regional tectonism.