摘要
塔里木盆地西南∈—Q的完整地层层序分布较为广泛, 可划分出14个等时地层单元.早古生代沉积相以浅海台地相碳盐岩沉积为主,后期海退出现了陆地边缘相碎屑岩.总体经历了由碳酸盐岩台地相向碎屑岩台地相演化的沉积旋回.晚古生代是由海变陆的转折时期,区内经历了较大规模的来自北西向天山海和南西向昆仑海的石炭纪最大海侵,海水几乎覆盖了整个地区.晚二叠世海水全部退出塔里木西部,整个地区上升为陆.中生代由于盆地与山系的相对升降运动比较剧烈,昆仑山和天山急剧抬升,研究区只是缓慢进行着基底断块活动,形成陆盆.在中生代末期还遭受了相当规模的海侵,直至始新世末.新生代塔西南坳陷下沉,接受古近—新近纪沉积,而麦盖提、巴楚、柯坪地区抬升为陆,缺失该期沉积.渐渐世开始,才开始接近沉积,直至中新世形成统一沉积盆地.
A complete sequence from ∈—Q overlying the Precambrian basement is present in the southwestern region of Tarim basin. And 14 isochronous stratigraphic units could be subdivided. The early Paleozoic sedimentary facies is similar with that of the whole basin, composed of carbonate platform sediments followed by shallow marine clastic sediments, reflecting a sedimentary cycle from carbonate platform facies to clastic platform facies. The late Paleozoic is important for study of change from sea to land. A large-scale transgression occurred during the Carboniferous in the area, from Tianshan sea in the NW and Kunlun sea in the SW. Up to the late Permian the area was uplifted to land after seawater totally retreated. The contrasting uplift and depression of mountains and basins led to the rapid uplift of Tianshan and Kunlun mountains. While in the study area, only faulted basement blocks are moving slowly, resulting in formation of continental basin. Another large-scale transgression occurred during the end of the Mesozoic, and lasted to the end of Eocene. The development of Tarim basin reached its peak during the Cenozoic. The southwestern Tarim depression subsided, with sedimentation of Paleogene-Neogene rocks. While the areas in Maigaiti, Bachu and Kepin were uplifted to land with no synchronous sedimentation. These areas started to receive sediments at the beginning of Oligocene, and became part of a unified sedimentary basin up to the Miocene.
出处
《新疆地质》
CAS
CSCD
2002年第z1期78-82,共5页
Xinjiang Geology
基金
国家95重点科技攻关项目(961110310)资助
关键词
塔里木盆地西南
古生代
沉积相特征
southwestern Tarim basin
Paleozoic
sedimentary facies
