塔里木盆地上泥盆统与石炭系层序地层分析

Sequence Stratigraphic Analysis of the Neodevonian—Carboniferous in the Tarim Basin

塔里木盆地晚泥盆世—石炭纪为远离陆棚边缘的陆棚内部碎屑岩和碳酸盐岩陆表海沉积环境，在层序地层分布模式上与Ｖａｉｌ等根据被动大陆边缘盆地提出的层序地层分布模式有所不同。共将上泥盆统—石炭系划分出五个层序，十四个体系域。其中，第Ｉ层序是在快速的海平面上升和陆源碎屑物质快速补偿条件下形成的；第Ⅱ层序代表陆源物质补给由快变慢的条件下形成的；第Ⅲ层序代表海面由慢速上升至快速下降过程中且陆源物质补给相对稳定条件下形成的；第Ⅳ层序代表海平面快速上升与陆源物质补给相对稳定的条件下形成的；第Ⅴ层序是在快速海平面上升及陆源物质供给补偿不足的条件下形成的。塔里木盆地晚泥盆世—石炭纪的沉积史是在相对海平面呈阶段性上升的海侵过程中发生的，可将这一时期的海平面变化划分为五个二级周期旋回。其中构造作用对第Ｉ、Ｉ、Ｖ周期的形成起了重要的作用。

Tarim Basin, enclosed or semienclosed by the paleocontinent or islands on the south, north and east, was the vast epicontinental sea on the continental shelf in the Neodevonian-Carboniferous which formed a series of multitype and multicyclic carbonate rocks, evaporites, clastic rocks and transitional rocks. The sequence stratigraphic patterns of the Tarim Basin are different from those proposed by P.R.Vail et al. mainly on the basis of passive continental margin basins.The Neodevonian-Carboniferous of the Tarim Basin can be divided into five sequences and subdivided into fourteen system tracts. The Sequence I was formed under the conditions of the rising of sea level and quick compensation of more terrigenous clastic materials.The Sequence Ⅱ formed in an environment in which the feeding of terrigenous materials changed from quick to slow.The Sequence Ⅲ formed in an environment in which the rising of sea level changed from quick to slow and the feeding of terrigenous clastic was relatively constant.The Sequence Ⅳ formed in an environment in which the rising rate of sea level gradually slowed down and terrigenous clastic feeding was relatively constant,and the Sequence Ⅴ formed in an environment of quick rising of sea level and lacking of terrigenous clastic feeding. The Neodevonian-Carboniferous deposition in the Tarim Basin occurred during a general transgression process of rising of the relative sea level by stages. The changes of the sea level in the Neodevonian～Carboniferous may be divided into five 3rnd order cycles, of which the generation of the Cycle Ⅰ、Ⅱ、Ⅴ were mainly controlled by the regional tectonism and the others by the eustasy.