内蒙古乌拉特后旗乌兰敖包地区石炭系—二叠系阿木山组沉积环境

对内蒙古乌兰敖包地区野外剖面进行观测,结合剖面岩性组合、地层古生物、沉积构造、岩石学等沉积特征分析,认为剖面整体分为3段。下段为辫状河三角洲相向滨海相过渡,中段为碳酸盐台地相,上段为滨、浅海相。剖面沉积特征反映了该区石炭系—二叠系阿木山组沉积环境位于盆地边缘,经历了陆相向海相的转变,属于上超沉积。沉积相研究及边缘相的确定从沉积学角度证明额济纳旗及其邻区在石炭纪—二叠纪时期是一个裂谷盆地。研究成果可为盆地演化和沉积相研究提供依据。

Sedimentary environment of Carboniferous-Permian Amushan Formation in Wulanaobao area of Urad Rear Banner, Inner Mongolia.

Based on field section survey of Wulanaobao area in Inner Mongolia and an analysis of such sedimentary features as litho- logic composition, stratigraphy, paleontology, sedimentary structure and petrology, the authors divided the section into three segments. The lower segment is braided river delta facies transformed into littoral facies, the middle segment is carbonate platform facies, and the upper segment is littoral and neritic facies. These sedimentary features suggest that in the Carboniferous-Permian Amushan period this area was located at the edge of the basin and experienced transformation from continental facies to marine facies, belonging to an onlap deposition process. In addition, the research on sedimentary facies and the determination of marginal facies prove that in the Carbonif- erous-Permian period Ejin Banner and its adjacent areas constituted a rift basin from the angle of sedimentology. The results of the re- search provide some evidence for the study of basin evolution and sedimentarv facies.