华北地区中奥陶统蒸发盐岩溶解坍塌角砾岩化作用  

SOLUTION-COLLAPSE BRECCIATION OF THE MIDDLE ORDOVICIAN EVAPORITES IN NORTH CHINA

作　　者：王兆升 沙庆安[1] 

机构地区：[1]中国科学院地质研究所,北京100029

出　　处：《地质科学》1991年第3期246-253,T001,共9页Chinese Journal of Geology(Scientia Geologica Sinica)

摘　　要：华北地区中奥陶统下马家沟组第二、四段及上马家沟组第三段广泛分布着三层角砾岩。角砾岩系由蒸发盐溶解致使其白云岩夹层及残留蒸发盐岩沉陷坍塌所形成。这是一个复杂的过程,可划分为四个阶段:1.蒸发盐岩层塑性变形和矿物相的转变导致原生沉积构造破坏和部分角砾岩化;2.形成具蒸发盐和白云石基质的角砾岩;3.形成具白云石基质的角砾岩;4.形成细-粗晶石灰岩、角砾灰岩。The Middle Ordovician breccia is widely distributed in the Second and Fourth Members of the Lower Majiagou Formation and the Third Member of the Upper Majiagou Formation in North China. They were evidently formed by solution, subsidence and collapse of interbed-ded evaporites and dolomites. This process is very complicated and can be divided into four sages:1. Destruction of primary sedimentary structures and partial brecciation by plastic deformation of evaporites and by phase change of some minerals;2. Formation of breccias by solution, reprecipitation and flowing;3. Formation of breccias by further solution;4. Formation of fine -and coarse-grained limestones and brecciated Limestones by dedolo-mitization.

关 键 词：蒸发岩 中奥陶世 角砾岩 岩化作用 

分 类 号：P588.247[天文地球—岩石学]