内蒙古西部银额盆地及邻区二叠系隆林阶—冷坞阶层序地层格架

The sequence stratigraphic framework of Permian Longlinian-Lengwuan Stage in Yingen-Ejin Banner basin and its adjacent areas,western Inner Mongolia

依据露头层序地层学原理,对银额盆地及邻区二叠系隆林阶—冷坞阶露头剖面进行层序界面的识别和层序划分,共划分为2个Ⅲ级层序。在对东西、南北向层序地层对比的基础上,初步建立了研究区的层序地层格架。隆林期—罗甸期全区发生大范围的海侵接受海相沉积,以滨海—浅海陆棚相为主,局部发育碳酸盐岩台地相,盆地边缘发育过渡相沉积,有2个沉积中心,黑鹰山-额济纳旗坳陷带的沉积中心在碧云泉南-芦草井地区,柳园-巴丹吉林坳陷带的沉积中心在卡路山-杭乌拉一带。祥播期-冷坞期继承了前期的沉积格局,只是沉积范围向北西缩小,黑鹰山-额济纳旗坳陷带的沉积中心在芦草井地区,柳园-巴丹吉林坳陷带水体变浅,沉积中心在古硐井地区。

According to the basic principles of outcrop sequence stratigraphy, the strata of Permian Longlinian-Lengwuan Stage in Yingen-Ejin Banner basin and its adjacent areas are divided into two third-order sequences through sequence interface identification and sequence classification. The sequence stratigraphic framework of the study area was established by comparing E-W-trending and N-S-trending sequence stratigraphic criteria. In Permian Longlinian-Luodianian Stage, the study area was of marine facies deposition through marine transgression, mainly developed offshore and neritic shelf facies sediments, and partly developed carbonafite plateau fa- cies, with the development of transition facies sediments along the boundary of the basin. It had two depocenters. The depocenter of Heiyingshan-Ejin Banner depression was Biyunquannan-Lucaojing area, whereas the depocenter of Liuyuan-Badanjilin depression was Kalushan-Hangwnla area. The study area inherited the sedimentary framework of the early Permian Xiangboan-Lengwuan Stage, only the deposition range shrank northwestward. The depocenter of Heiyingshan-Ejin Banner depression was Lucaojing area. The water body of Liuyuan-Badanjilin depression became shallow, and the depocenter was Gudon^ing area.