蓟县地区雾迷山组风暴硅质岩沉积序列  

Origin of Siliceous Rock in Wumishan Formation,Jixian,Tianjin

作　　者：任国选[1] 孟祥化[1] 葛铭[1] 王德海[1] 郭峰[1] 

机构地区：[1]中国地质大学沉积盆地研究所,北京100083

出　　处：《地质科技情报》2007年第5期11-16,共6页Geological Science and Technology Information

基　　金：国际地质对比计划IGCP447项目(SC/GEO/546/447);科技部国家重点基础研究项目(001CB711002);国家自然科学基金项目(4017204340572073);中国地质调查局项目(200313000055)

摘　　要：从岩石学和沉积学方面对蓟县雾迷山组硅质岩沉积序列的研究表明,蓟县雾迷山组硅质岩沉积为典型的风暴沉积。蓟县雾迷山组广泛发育风暴沉积,在硅质条带状白云岩中发育的硅质砾屑具奇特的菊花状构造,这种构造形成于成岩作用后期,在岩石尚未完全固结成坚硬的岩石时期,遭遇风暴破坏,将原有的水平层理打碎,继而被风暴流搅起,风暴流的涡动使得岩石碎片或直立,或呈发散状,后经成岩作用保留了这种构造形态,与上下岩层形成典型的风暴沉积序列。通过野外与镜下观察并结合有机地球化学分析得出,蓟县地区雾迷山组硅质岩来源于海底热水活动。风暴硅质岩有两种沉积环境,对于异地搬运再沉积的风暴硅质岩,其沉积环境为潮上坪低能环境,即开阔台地中的泛溢沉积;而对于原地型的风暴硅质岩,其沉积环境应该是潮间带,因此推测其沉积环境为碳酸盐岩台地前缘斜坡。The paper makes a series of research from petrology to sedimentology on siliceous rock in Precambrian Wumishan Formation, and works out that typical storm deposits are well developed in siliceous rocks in Wumishan Formation. Meanwhile, it is also found that the stromatolite and coagulum stone bioherm are well developed, which mainly consist of dolomite interbeded with siliceous rocks. The research shows that siliceous rocks are developed storm in this area, which have scouring surface and siliceous gravel arranged as daisy. These rocks were formed in storm surge, and destroyed in the late period of the diagenetic stage before they became consolidated or compacted, which resulted in the siliceous fragments straight on the under layers, and formed typical storm deposit. Stromatolithic dolomite interbeded with siliceous strip was normal weather deposit. And the origin of the siliceous rock mostly could be seemed as the thermal water activities offering the SiO2. It is concluded through the micro photo and field work that parts of the typical storm depositional series in Wumishan Formation were the fast and proximal sedimentary deposit in slope of the carbonate platform, and the other parts were transported from slope of the carbonate platform to the carbonate platform; at last they formed overflowing deposit.

关 键 词：硅质岩 风暴序列 雾迷山组 

分 类 号：P588.24[天文地球—岩石学]