论文部分内容阅读
依据洞穴充填物岩性、孢粉化石、主元素、痕量元素和稀土元素特征分析,结合区域构造演化资料,探讨了川中下寒武统龙王庙组大型洞穴的形成时期和充填过程。洞穴充填泥中孢粉化石时代为石炭纪—早白垩世,泥质岩具有高B含量、低Sr/Ba、稀土元素配分模式差别大的元素地化特征。认为龙王庙组洞穴主要形成于石炭纪—早二叠世古隆起大规模隆升暴露期,为风化壳喀斯特作用和顺层喀斯特作用叠加形成的,并经历了石炭纪—早二叠世的沉积充填和潜流携带古隆起高部位物质充填,及中生代—新生代构造活动期地表水携带溶解残余物沿断裂下渗充填过程。邻近龙王庙组尖灭线,受石炭纪—早二叠世风化壳喀斯特作用和顺层喀斯特作用影响的颗粒滩发育带为川中龙王庙组储层发育最有利地区。
Based on the characteristics of cave fillings, sporopollen fossils, major elements, trace elements and rare earth elements and the regional tectonic evolution data, the formation and filling process of the Longwangmiao large caves in the Central Sichuan Basin are discussed. The age of sporopollen fossils in the cave filling mudstone is Carboniferous-Early Cretaceous. The argillaceous rocks have the features of high content of element B, low Sr / Ba, and elemental features with large difference in REE patterns. It is concluded that the Longwangmiao Formation caves were mainly formed during the large uplift and expanse of the Carboniferous-Early Permian paleo-uplift, formed by superimposition of karst weathering and bedding karst, and experienced sedimentary filling of Carboniferous-Early Permian The subsurface flow carries the high-level material filling of the paleohighs and the infiltration and filling process of the dissolved water along the fault during the Mesozoic-Cenozoic tectonic activity period. Adjacent to the Longwangmiao Formation cut-off line, the granulite development zone affected by the Carboniferous-Early Permian weathering crust karst and the bedding karst play the most favorable area for the development of the Longwangmiao Formation in central Sichuan.