贵州三穗地区隆里组的沉积物源与沉积环境分析

Sedimentary Environments and Provenance Analysis of Longli Formation in Sansui Area,Guizhou Province

对贵州三穗地区隆里组砂岩的地球化学、稀土元素、微量元素及沉积构造进行了研究,分析了隆里组砂岩的物源方向、母岩类型及源区的构造背景:主要为长英质火成、镁质火成物源区,其次为火山弧物源区(基本为深成)和过渡区,物源是上地壳剥蚀而来,且隆起基底多为稳定克拉通,具有被动大陆边缘的构造背景。沉积构造与地球化学研究进一步证明,该地区隆里组为淡水环境沉积,是裂谷盆地由拉张裂陷演化为逐渐萎缩阶段沉积而成的产物。

Based on geochemistry, sedimentary structure, trace element and rare earth element analyses for sand- stone from Longli Formation in Sansui area of Guizhou Province, the provenance, mother rocks and tectonic back- ground are summed up. It is inferred that the mother rock belongs to felsic and magnesian magma rocks which form in stable continental, partially form in volcanic arc and transition zone. It is proposed that the provenance might be derived from upper crust, the uplift basement belongs to stable craton, and the tectonic background is passive continental margin. Sedimentary structures and geochemistry data from Longli Formation reflectes a fresh- water environment which correspond to the depression stage of rift basin extension.