蒙古国南戈壁省二叠系岩性组合特征及其与内蒙古银额盆地的对比

Characteristics of Permian lithic associations in South Gobi Province of Mongolia correlated with Yingen-Ejin Banner basin,Inner Mongolia

蒙古国南戈壁省中蒙边界地区分布多个二叠系大型—特大型煤矿,为一套以砾岩为主的粗碎屑岩和含煤系地层夹火山岩建造。银额盆地周缘地表剖面揭示,二叠系发育一套以海相沉积为主的碎屑岩+碳酸盐岩+火山岩建造。银额盆地希热哈达—赛汗桃来地区的钻井资料揭示其为一套粗碎屑岩+含煤系地层夹火山岩岩性组合,与盆地周缘地表剖面各时代地层的岩性组合均存在巨大差异,而与蒙古国南戈壁省二叠系的岩性组合特征相同。通过中蒙边界地区二叠系地层层序与岩性组合特征的对比,明确了银额盆地希热哈达—赛汗桃来地区钻井资料发现的含煤系地层时代为二叠纪,结合沉积充填特征,对银额盆地二叠纪沉积演化与沉积相平面展布有了新的认识,为银额盆地及邻区石炭纪—二叠纪构造演化的研究提供了新的证据。

There are lots of Permian large-superlarge coal mines in South Gobi province of Mongolia along the border area between China and Mongolia,and the strata are composed of coarse clastic rocks dominated by conglomerate and coal-bearing beds intercalated with volcanic rocks.Besides,Permian strata around Yingen-Ejin Banner basin comprise a suite of littoral facies deposits,which are mainly clastic rocks,carbonate rocks and volcanic rocks.Drilling data obtained from Xirehada-Saihantaolai area in Yingen-Ejin Banner basin revealed that there is a set of coarse clastic rock and coal-bearing beds intercalated with volcanic rocks,which are remarkably different from lithic associations of each era in the periphery of Yingen-Ejin Banner basin but are consistent with the characteristics of Permian lithic associations in South Gobi province,Mongolia.Based on the comparisons of characteristics of Permian stratigraphic sequences and lithic associations along the border area between China and Mongolia and the study of stratigraphic ages of coal-bearing strata discovered by drilling in Xirehada-Saihantaolai area,the authors assign the Yingen-Ejin Banner basin to Permian.Combined with the characteristics of sedimentary sequences,the authors have gained a better understanding of the Permian sedimentary evolution and the planar distribution features of sedimentary facies,which provides some new evidence for the research on Carboniferous-Permian structural evolution in Yingen-Ejin Banner basin and its vicinities.