Study on Characteristics and Its Stratigraphic Classification and Correlation of Cambrian in Sichuan Basin

Based on the theory of multiple stratigraphic classification,by the analysis and study of outcrop,drilling and logging data,as the study of Sichuan Basin and its adjacent areas' different division program of Cambrian,together with the characteristics of lithostratigraphic,paleontological and electrical,Cambrian of Sichuan Basin can be divided into five Formations: Qiongzhusi,Canglangpu and Longwangmiao Formation of lower Cambrian,Douposi Formation of middle Cambrian,and Xixiangchi Formation of Middle-Upper Cambrian.Conduct a detailed study of the lithological characteristics,Qiongzhusi Fm.is mainly composed of carbonaceous shale,shale and mudstone;Canglangpu Fm.is mainly composed of siltstone and argillaceous siltstone;Douposi Fm.is mainly composed of oolitic limestone,calcite dolomite and dolomite;the lower part of Douposi Fm.is mainly composed of argillaceous dolomite folded aubergine mudstone,the upper part of Douposi Fm.is mainly composed of aubergine argillaceous siltstone,dolomitic siltstone,folded aubergine mudstone;Xixiangchi Fm.is mainly composed of large set of thick bedded aplite-dolomite and crustal powder dolomite.Cambrian of Sichuan Basin is widespread and thick,only exists a Northeast erosion area of the western basin.There is a thickness of low-value area in the south-central basin,east,south,north thickness increases.