四川盆地寒武系划分对比及特征

以多重地层划分理论为指导,根据露头、钻井和测井资料的综合分析,在总结对比四川盆地及其邻区寒武系不同时期﹑不同构造单元地层划分方案的基础上,以岩石地层特征为主要依据,综合分析古生物特征及电性特征,将四川盆地寒武系自下而上划分为:下寒武统筇竹寺组、沧浪铺组和龙王庙组,中寒武统陡坡寺组,中上寒武统洗象池组。对岩性特征进行了详细研究,筇竹寺组主要为炭质页岩﹑页岩及泥岩;沧浪铺组主要为粉砂岩及泥质粉砂岩;龙王庙组主要为鲕粒灰岩﹑灰质白云岩及白云岩;陡坡寺组下部为泥质白云岩夹紫红色泥岩,上部为紫红色泥质粉砂岩﹑白云质粉砂岩夹紫红色泥岩;洗象池组主要为大套厚层状细晶白云岩﹑粉晶白云岩。四川盆地寒武系分布广泛且厚度较大,仅在盆地西部存在一个北东向剥蚀区,整体上在盆地中南部形成一个厚度低值区,向东﹑向南﹑向北厚度逐渐增大。

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 lithologieal characteristics, Qiongzhusi Fm. is mainly composed of carbonaceous shale, shale and mudstone; Canglangpu Fm. is mainly composed of sihstone and argillaceous sihstone; 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 sihstone, dolomitic siltstone, folded aubergine mudstone; Xixiangchi Fro. 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.