济阳坳陷古近系页岩的纹层组合及成因分类

Laminae Combination and Genetic Classification of Eogene Shale in Jiyang Depression

在济阳坳陷古近系中发育大量湖相页岩及纹层状的碳酸盐岩,页岩类型多样。通过对300多块页岩薄片的显微镜下观察分析表明,这些湖相页岩和纹层状碳酸盐岩均由3种基本纹层构成:富有机质纹层(即富含有机质的黏土矿物纹层)、隐晶碳酸盐纹层和黏土纹层。按纹层组合和比例的不同,可将页岩和纹层状碳酸盐岩系统地划分为黑页岩、钙质纹层页岩、富有机质纹层页岩、泥页岩、钙质页岩、纹层状泥灰岩和纹层状灰岩等7种类型,并尝试提出利用纹层组分划分页岩类型的三角形成因分类方案。由于不同纹层形成的古湖泊条件不同,该分类方案不仅能够反映各种页岩的纹层组成,同时也可反映页岩的成因。

Various types of lacustrine shale and laminated carbonate rock are extensively developed in Eogene of Jiyang depression. Observation and analysis under microscope of more than 300 shale thinsections show that these lacustrine shale and laminated carbonate rock are all composed of three basic laminae which are organic-rich laminae （i. e. , organic-rich clay mineral laminae）, aphanitic carbonate laminae and clay laminae. According to the difference of laminaecombination and proportion, seven types of lacustrine shale and laminated carbonate rock can be systematically classified, which are black shale, calcareouslaminated shale, organic-rich laminated shale, mud shale, calcareous shale, laminated muddy limestoneand laminated limestone. Meanwhile, based on the laminae component, a triangular genetic classification scheme is alsoproposed. Since different laminae are formed in different ancient lake conditions, the proposed classification scheme canindicatetheir laminae composition and genesis.