燕山冀北凹陷雾迷山组沉积相研究

Study of Sedimentary Facies of the Neoproterozoic Wumishan Formation in the Jibei Depression, Yanshan Mountains

在收集前人及野外采集资料基础上,利用薄片鉴定、岩石密度分析,对冀北坳陷中新元古界雾迷山组的岩石类型与特征、沉积相标志、剖面相研究了其沉积相类型。结果认为研究区属于典型的陆表海碳酸盐台地沉积环境,根据岩性及叠层石特征可细分为潮下、潮间和潮上带。其中一、二段由近35个小型韵律层组成了一个完整的由海侵到海退的沉积序列,具有自潮下至潮间再至潮上的潮坪相为主的沉积样式,为典型的雾迷山韵律沉积。第三段小型叠层石只见于三段的下部,而从第12层开始出现大型叠层石。第四段灰质白云岩中含沥青质块体,层理一般平直,或微波状,有时可见斜层理和波痕,为潮间带-潮下带沉积。

This paper has a discussion rock types and their characteristics and sedimentary facies and their marks of the Neoproterozoic Wumishan Formation in the Jibei Depression. The study indicates that the studied area belonged to typical epeiric sea carbonate platform sedimentary environment which bay be divided into subtidal, intertidal and supratidal zones based on lithologie character and stromatolite. The first and the second Members constitute a complete transgressive-regression sequence which is typical rhythmic deposit of the Wumishan Formation. The third Member yields small stromatolite in the lower and large stromatolite in the upper. The forth Member is a deposit in intertidal and subtidal zones.