龙门山南段前陆盆地中-新生代砂岩特征及物源分析

龙门山南段前陆盆地发育了巨厚的陆源沉积岩，其中砂岩分布最广、含量最多。在详细观察描述砂岩宏观特征的基础上，通过薄片鉴定、粒度分析等方法，研究了中—新生代砂岩的物质成分及结构特征，指出砂岩的成分成熟度和结构成熟度均中等至低，并按成分—成因分类方法划分了砂岩的岩石类型。根据砂岩特征，分析岩石的组成物质来源于龙门山造山带，再结合前陆盆地充填地层的沉积特征，提出了砂岩的沉积模式。

Characteristics and provenance analysis of the Mesozoic and Cenozoic sandstone in the foreland basin of the south part of Longmenshan Mountain

Terrigenous sediment rock develops with a great thickness in the foreland basin of the south part of Longmenshan Mountain, but the sandstone of which distributes most widely and its content ranks first. On the basis of observing and describing the macro characteristics of the sandstone in detail, the mineral composition and texture of the sandstone of Mesozoic and Cenozoic are studied by means of thin section and grain size analysis, the results show that both the composition maturity and texture maturity range from middle to low. The sandstone is classified, according to the scheme of genesis composition. In the light of the characteristics of sandstone as well as sedimentary features of deposited strata in the foreland basin, it is concluded that the provenance of the sandstone is Longmenshan orogenic belt, and the sedimentary model is established finally.