寒武系凝块石生物丘的沉积组构：以鲁西地区张夏组为例

摘要

Thrombolite is a non-laminated fabric of microbial carbonate,which is in a sharp contrast with strom-atolite that is characterized by the laminated fabric.Thrombolite bioherm developed in Cambrian Zhangxia For-mation in the western Shandong Province mainly consists of clots,which are composed of dense micrite and mi-crospar.Both the remain of calcified extracelluar ploymers (EPS)and calcified cyanobacteria fossils are ob-served within the clots that make up thrombolite.Within the complex microscopic fabrics it can be observed that the remain of calcified EPS is marked by the spherical structure,the sheet structure,the mat structure and the honeycomb-like structure,and it further indicates that the formation of clots within thrombolite should belong to a complex organic mineralization process.Together with both the dense micrite and the calcified cyanobcteria fossil,the calcified EPS provide some important information for understanding the enigmatic formation mecha-nism of thrombolites.Therefore,the study of Cambrian thrombolite bioherm can provide an important clue and approach for the further research.%凝块石是一种不具纹层状组构的微生物碳酸盐岩，与纹层状组构的叠层石形成鲜明对照。鲁西地区寒武系张夏组中的凝块石生物丘主要由致密泥晶和微亮晶组成的团块构成，在团块中可见到细胞外聚合物质（EPS）钙化作用的残余物及钙化蓝细菌化石。在复杂的微观组构中，表现出球状结构、片状、席状及蜂窝状结构的 EPS 钙化残余物，说明凝块石中团块的形成是一个复杂的有机矿化作用过程。这些 EPS 钙化残余物与较为普遍的致密泥晶和钙化蓝细菌化石一起，为了解凝块石的形成机理提供了一些重要信息。因此，对凝块石生物丘的分析也为今后的深入研究提供了一个重要线索和思考途径。