Abstract Among the varieties of microbial carbonate rocks, leiolites are rare in ancient rock records and have only few examples in the modern environment, which makes them difficult to study. This study documents the sedimentary environment, characteristics and composition of microbial carbonates, dominated by calcified microbes, which developed in the Cambrian Miaolingian Xuzhuang Formation on the North China Platform. The upper part of the formation in the Xinji section of Lushan City, Henan Province is bounded by a drowning-unconformity surface of a third-order depositional sequence. Beside the development of an ooid shoal in response to sea-level fall, a bioherm dominated by leiolite also developed in the upper part of the Xuzhuang Formation. These leiolites represent special sedimentary phenomena due to their occurrence with high-energy ooid shoals. Microscopically, they are characterized by abundant calcified cyanobacteria fossils, such as dichotomous-branching Epiphyton and filamentous cyanobacteria, thus showing the diversity and complexity of the cyanobacterial microbial mats that predominate the leolitic bioherm. Four groups are confirmed for Epiphyton based on the morphological characteristics of calcified filaments. The filamentous cyanobacteria can be divided into Girvanella and Subtifloria, and their possible forming mechanisms are discussed. The macroscopic and microscopic characteristics of the current leiolites provide important research clues and typical examples for understanding the origin of the Miaolingian leiolitic bioherm and its paleoenvironmental significance.

中文翻译：

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以钙化微生物为主的中寒武统粳石生物礁的发育——以辛集剖面（华北地台）为例

摘要 在微生物碳酸盐岩的种类中，燧岩在古代岩石记录中很少见，在现代环境中的例子也很少，研究难度很大。本研究记录了在华北地台寒武系庙岭阶徐庄组发育的以钙化微生物为主的微生物碳酸盐的沉积环境、特征和组成。河南省庐山市辛集段地层上部以三级沉积层序淹没不整合面为界。徐庄组上部除了响应海平面下降而发育鲕粒滩外，还发育了以砑光岩为主的生物礁。由于它们与高能鲕粒浅滩一起出现，这些砗磲岩代表了特殊的沉积现象。微观上，它们以丰富的钙化蓝藻化石为特征，如二分枝附生藻和丝状蓝藻，从而显示出占主导​​地位的青橄榄岩生物礁蓝藻微生物垫的多样性和复杂性。根据钙化丝的形态特征，确定了四组附生菌。丝状蓝藻可分为Girvanella和Subtifloria，并讨论了它们可能的形成机制。现今燧石的宏观和微观特征为了解苗岭期碲岩生物礁的成因及其古环境意义提供了重要的研究线索和典型实例。