中文摘要：

微生物碳酸盐岩是微生物与环境相互作用的产物，它的发育对古环境与微生物群落有着重要的指示意义。河北省平泉县地区中元古代高于庄组四段发育有凝块石、纹理石、叠层石多种微生物碳酸盐岩。凝块石以其内部独特的凝块组构而显著区别于具纹层构造的叠层石等其它微生物岩类型。根据尺寸大小与排列特点可将高于庄组凝块石中的凝块组构分为3种类型：厘米级别、致密的中凝块，毫米级别、似层状的小凝块与微米级别、层状分布的微凝块。显微与超显微观察显示，所有的凝块组构均由内核与外壳两个结构单元组成。内核主要为丝状细菌、球状细菌等微生物或有机质残留，围绕内核的是呈放射状、扇状分布的方解石外壳，方解石颗粒之间可见有薄片状胞外聚合物（EPS）残留。凝块中微生物残余及EPS的大量发现，表明了凝块组构的形成与微生物密切相关。环境中海水碳酸盐初始饱和度的高低可能是形成不同类型的凝块组构的原因。

英文摘要：

Microbial carbonate is the product of microbes interact with the environment,and has important significance to the ancient environment and microbial community. There are thrombolites, laminates and stromatolites in Mesoproterozoic Gaoyuzhuang Formation from Pingquan area,Hebei Province. Thrombolites characterized by clotted fabrics is significantly different from the other microbialites who have the laminated structure. Thrombolite in Gaoyuzhuang Formation is divided into three types by the size and arrangement characteristic of their clotted fabrics. They are centimeter level dense mesoclot,millimeter level stratoid miniclot and micrometer layered microclot. Microscopic and ultra-microscopic observation showed that all the clotted fabrics are made up of core and outer layer. The main component of nucleus are the microorganism,like coccoidal and filamentous bacteria,or residual organic matter,surrounding by the radial or fan-shaped distribution of calcite shell,and mucus-to film-like extracellular polymeric substance （EPS） is visible between the calcite particles. Large quantities of residual microorganism and EPS found in clot showed that the formation of clot is closely related to the microorganisms. Different initial saturation of the environment may be the cause that formed different types of thrombolite.