川东北下三叠统飞仙关组白云岩成因及分布

THE ORIGIN AND DISTRIBUTION OF DOLOSTONE IN FEIXIANGUAN FORMATION IN LOWER TRIASSIC SERIES, NORTHEAST SICHUAN

根据白云石的沉积学、岩石学、地球化学等理论,对四川盆地东北部地区下三叠统飞仙关组白云岩地球化学特征及岩石学特征进行了多种技术分析,认为飞仙关组白云岩有混合水白云石化和回流渗透白云石化两种成因类型。混合水白云石化形成的鲕粒白云岩主要沿台地边缘呈带状分布,回流渗透白云石化形成的膏质泥晶白云岩或膏质砂屑白云岩呈片状分布于泻湖环境中。进行了白云石化分区分带研究,为下步勘探部署指明了方向。

According to the geochemistry, sedimentology, lithology, the dolostone in Feixianguan Formation in lower Triassic series, northeast Sichuan is studied in terms of geochemistry and lithology, it is pointed out there are two kinds of dolomization in Feixingguan Formation, they are mixed-water and seepage-reflux dolomitization. Oolitic dolostone formed by mixed-water dolomitization distributes along platform edge in the shape of band. Gypsiferous mi-crocrystal dolostone and dolarenite formed by seepage-reflux dolomitization distributes planarly in lagoon. Distribution research of dolomitization is made, and next exploration target is pointed out.