内蒙古通辽南部石炭纪岩相古地理特征

Carboniferous lithofacies-paleogeography in the southern part of Tongliao ,Inner Mongolia

研究区位于内蒙古自治区奈曼旗和库伦旗南部。构造区划属于华北板块北缘的天山—赤峰活动带[1]。区内晚石炭世地层以陆源碎屑岩和碳酸盐岩沉积为主。二者在空间上具有相变关系。按微相组合或基本层序、沉积构造、生物特征及其空间分布规律,可划分出滨岸相、潮坪相、台后盆地相及台地相4种岩相,8个微相。它们构成一个较为完整的海进层序,属于海侵体系域沉积。反映华北板块北缘晚石炭世海槽属于被动陆源盆地—即陆表海环境。

Located in the Naiman Banner and southern Hure Banner,Inner Mongoli a,the study area tec-tonically belongs to the Tianshan-Chifeng mobile belt on the northern margin of the North China plate.The Late Carboniferous strata i n the area consist dominantly of terrestrial clastic rocks and carbonate rocks ,which have a facies change relation in space.According to the microfacies ass emblage or essential sequence,sedimentary structures,biological features and their spatial distribution characteristics,four facies,namely lit-toral faci es,tidal-flat facies,back-platform basin facies and platform facies,and eig ht microfacies may be distinguished;they form a relatively complete transgress ive sequence,belonging to deposits of the transgres-sive systems tract.This suggests that the Late Carbonate sea trough on the northern margin of the Nort h China plate is a passive terrestrial basin,i.e.the epicontinental environme nt.