安徽巢北地区下志留统坟头组沉积环境分析

巢北地区下志留统坟头组出露较好.巢北志留系仅发育下统高家边组、下统坟头组,缺失下统茅山组,志留系组成背斜核部.坟头组沉积物组分为石英细砂岩、泥质细砂岩夹粉砂质泥岩,向上变为互层状细碎屑沉积物.本文以巢湖7410厂剖面坟头组地层为研究对象,通过该区地层的野外形态和镜下特征的研究,以及成因分析、成岩后生变化的观察,同时,配合野外构造和薄片粒度分析等方法对沉积环境进行了判别分析.通过分析认为本地区坟头组属于沉积速度较快的滨浅海-陆棚相沉积环境.

ANALYSIS OF SEDIMENTARY ENVIRONMENT OF THE FENTOU FORMATION OF LOWER SILURIAN IN THE NORTHERN CHAOHU AREA,ANHUI

The Fentou Formation of lower Silurian is well outcropped in the northern Chaohu area,where the Silurian strata only consists of the lower series of Gaojiabian Formation and Fentou Formation,without Maoshan Formation.The Silurian strata make up the anticline core.The Formation is composed of quartz fine-grained sandstone,muddy fine-grained sandstone intercalated with silty mudstone,changing upwardly to interbedded fine-clastic sediments.On the basis of the Fentou Formation disclosed by the profile across Chaohu No.7410 Factory,including field survey of strata forms,optical features study,genetic analysis,observation of post-diagenetic changes,structures and thin-section analysis of samples,this paper analysed the sedimentary environment,which was thought to be littoral-shallow sea-continental shelf facies of quick sedimentation.