内蒙古桌子山中奥陶统拉什仲组沉积特征及沉积环境

he middle Ordocivian Lashizhong Formation in Zhuozishan Area contained mainly of grayish-green sandstone,siltstone,shale and conglomerate,it could be divided into three members.Based on a analysis of the lithologic charater,sedimentary structure,palaeobiologic fossils and geochemical indicators,the authors hold that the sedimentary environment of Lashizhong Formation was a deep-water slope to basin environment. The results of sedimentary facies analysis show that the first member and the third member formed by submarine fan located in the continental slope,which can be further divided into two sedimentary subfacies--distributary channels and inter-channels in the middle fan,the second member formed in the deep-water basin far from the continent.Litho-section on the whole covers a complete sedimentation cycle of marine transgression and marine ingression.