关键词: 塔里木盆地, 晚第三纪, 第四纪, 环境演变, 古植被

Abstract: The Tarim Basin has undergone a process from the gradua formation of a wide united basin combinedwith separated basins, then to the wilting evolution of the basin.The landforms of the basin has occured a complex changing process with change of deposition center because of the tectonic movement.Finally the condition of the basin with higher at the southwest and lower at the northeast.The climate of the Tarim Basin had obvious evidence of changing into arity from Miocenc time to Pliocene time.The arity was developed during Quaternary period.Semi-desert and desert formed and gradually increased since Pliocene time.Extremely arid desert was formed at the basin center in late Pleistocene time. Late Pleistocene time was also a most important period of the enlargement of sandy desert, although limited sandy desert might present earlier.The arid environment of the Tarim basin has existed for long.Although there were several small fluctuations from arity to moisture, the arid condition has never changed, and also there is no evidence of extremely deterioration lately.Embryonic form of the Tarim River was probably formed in early Pleistocene.Then the river went to prosperous time during the Mid-Pleistocene.The branches of the river is continuously tending to move castward today.