新构造运动在塔里木盆地演化中作用

THE ROLE OF THE NEOTECTONIC MOVEMENT IN THE EVOLUTION OF THE TARIM BASIN

在第四纪以来的新构造运动的影响下,塔里木盆地逐渐向封闭的干旱盆地演化。由于波动式的新构造运动在每阶段表现的形式有差异,因而盆地的演化也相应表现出明显的阶段性。该盆地新构造运动大致经历了上新世末—早更新世、早更新世末—中更新世以及晚更新世三个阶段,其中以早更新世末的一次构造运动对盆地的地貌影响最大。新构造运动是由印度板块和欧亚板块挤压引起的,故塔里木盆地与青藏高原的演化阶段在时间上大致吻合。

The Tarim Basin has gradually evolved into a closed arid basin under theinfluence of the neotectonic movement since the Quaternary. The process of the basinevolution can be divided into three stages. In the first stage, i. e. from the end of the Pliocene to the early Pleistocene,the margins of the Tarim basin sank intensely and the basin became widea; gentlepiedmont belt appeared around the basin, and desert of certain scale began to formin the centre of the basin. In the Second stage, i.e.from the end of the early Pleis-tocene to the mid--Pleistocene, the basin was deformed and narrowed, and the neo-tectonic movement brought about large--scale migration of rivers and lakes and chan-ges of the types and distribution of deposits, rivers and lakes. Meanwhile, the devel-opment of the landform of sand mounds might have been restricted to a certainextent. The late Pleistocene is the third stage. Since then the neotectonic move-ment in the basin has been attenuated; the active fractures on the margins of thebasin have been developed, which are also more or less manifested in the centralpart but relatively weak; the landform of sand mounds has expanded rapidly. Theblock activity of the basement caused the deformation of the covers.