四川盆地蜀南地区寒武系地层划分及对比研究

Characteristics and Stratigraphic Classification and Correlation of Cambrian on South Sichuan Basin

通过对大量单井及地面露头资料的研究,并在对比前人对四川盆地蜀南地区及其邻区寒武系地层划分方案的基础上,以岩石地层特征为主要依据,综合分析了该层系古生物特征及电性特征,将其自下而上四分为下寒武统九老洞组和龙王庙组,中寒武统高台组,中上寒武统洗象池群,并对其地层特征及展布进行了分析,指出下寒武统九老洞组以碎屑岩为主,夹少量碳酸盐岩,下寒武统龙王庙组以海相碳酸盐岩为主,中寒武统高台组为碎屑岩与海相碳酸盐岩混合沉积,中上寒武统洗象池群为海相碳酸盐岩沉积;寒武系各组(群)地层西薄东厚、北薄南厚,整体呈西北薄、东南厚的展布形式。

Abstract：By analysis and study of bulk of wells and outcrops, on the basis of generalizing various structures and stratigraphic classifications of Cambrian strata of different periods in south Sichuan basin, in terms of lithostratigraphic characteristics and comprehensive analysis of its paleontologic characteristics and rock resistivity, the Cambrian strata in south Sichuan basin can be divided into four formations. Jiulaodong and Longwangmiao Formations of Lower Cambrian, Gaotai Formation of Middle Cambrian, and Xixiangchi Group of Middle-Upper Cambrian. Study on the stratigraphic characteristics and distribution indicates that the Jiulaodong Formation of Lower Cambrian mainly develops clastic rock with little carbonate rock, the Longwangmiao Formation of Lower Cambrian mainly develops marine carbonate, the Gaotai Formation of Middle Cambrian develops mixing deposit of clastic and marine carbonates, and the Xixiangchi Group of Middle-Upper Cambrian develops marine carbonates. The thickness of each Cambrian Formation （Group） in the study area decreases gradually from southeast to northwest.