混积岩一例——滇东震旦系陡山沱组砂质砂屑白云岩的成因  

AN EXAMPLE OF HUNJI ROCK──ORIGIN OF SANDY DOLOARENITE OF THE SINIAN DOUSHANTUO FORMATION IN EASTERN YUNNAN PROVINCE

作　　者：沙庆安[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029

出　　处：《古地理学报》2001年第4期56-60,共5页Journal of Palaeogeography：Chinese Edition

摘　　要：滇东震旦系陡山沱组顶部的砂质砂屑白云岩是一例典型的混积岩 ,即狭义的混合沉积。岩石中的石英砂分选好 ,圆度和球度高 ,它们时稀时密地呈“悬浮”状散布在白云石砂屑沉积物中。其产状及结构构造特征表明 ,它是当时的海滩砂在海进过程中被搬运到海洋中 ,并与白云石砂屑混合而形成的。The sandy dolarenite of the Sinian Doushantuo Formation in the eastern Yunnan Province is a typical example of hunji rock, a mixed sediments in narrow sense. All sand grains are quartz sands. Sorting and roundness and sphericity of particles are in good grade-level. Quartz sands are scattered in microcrystalline dolomitic sands in 'floating' state. The occurrence and texture and structure of sandy dolarenite show that the beach sands was transported into to the sea in the process of transgression, and mixed with dolomitic interclastics.

关 键 词：混积岩 震旦系 砂质砂屑白云岩 混合沉积 

分 类 号：P588.2[天文地球—岩石学]