The Cambrian strata in the North China Platform are fully exposed. A wide variety of carbonate oncoids with different shapes occur in the Xuzhuang and Zhangxia formations (Miaolingian Series) from six Cambrian sections in the study area. A comprehensive study involving outcrop description, microscopic observation, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and carbon and oxygen isotope analysis is conducted to determine the facies, morphology, internal structure, and geochemical properties of the oncoids. The oncoids are divided into six types based on their morphology and internal structure. Microscopic and ultrastructural observations reveal typical microbial fossils ( Girvanella ) and microbially-related sediments (framboidal pyrite), indicating the biogenicity of the oncoids. Additionally, the XRD and carbon and oxygen isotope analysis results suggest that the formational environments of these oncoids are different due to terrestrial influences. Statistical data on the oncoids from the six sections show that there are obvious differences in the types of oncoids and the proportions of different varieties in each section. The spatial differences in the oncoid morphologies are associated with different palaeogeographic settings. The rough oncoid growth patterns developed in nearshore environments were influenced by terrigenous debris and steep terrain, whereas the delicate oncoid growth patterns developed in offshore environments were less affected by terrestrial factors and were featured by more stable depositional processes related to microbial mats.

中文翻译：

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华北地台寒武纪类核生物的形态特征及对古地理的响应

华北地台寒武系地层充分出露。研究区6个寒武系剖面的徐庄组和张夏组（庙岭系）发育多种不同形状的碳酸盐岩类。进行了涉及露头描述、显微观察、扫描电子显微镜 (SEM)、能量色散 X 射线光谱 (EDX)、X 射线衍射 (XRD) 和碳氧同位素分析的综合研究，以确定相、形貌、类瘤的内部结构和地球化学性质。类瘤根据其形态和内部结构分为六种类型。显微和超微结构观察揭示了典型的微生物化石 (Girvanella) 和微生物相关沉积物 (framboidal pyrite)，表明 oncoids 的生物成因。此外，XRD 和碳氧同位素分析结果表明，由于陆地影响，这些类瘤的形成环境有所不同。6个断面的类圆粒统计数据表明，各断面类圆粒的种类和不同品种的比例存在明显差异。瘤状体形态的空间差异与不同的古地理环境有关。在近岸环境中发育的粗糙的类癌生长模式受到陆源碎屑和陡峭地形的影响，而在近海环境中发育的精细的类癌生长模式受陆地因素的影响较小，并且具有与微生物垫相关的更稳定的沉积过程。XRD和碳氧同位素分析结果表明，这些类瘤的形成环境因陆地影响而不同。6个断面的类瘤统计数据表明，各断面类瘤的种类和不同品种的比例存在明显差异。瘤状体形态的空间差异与不同的古地理环境有关。在近岸环境中发育的粗糙的类癌生长模式受到陆源碎屑和陡峭地形的影响，而在近海环境中发育的精细的类癌生长模式受陆地因素的影响较小，并且具有与微生物垫相关的更稳定的沉积过程。XRD 和碳氧同位素分析结果表明，这些类瘤的形成环境因陆地影响而不同。6个断面的类圆粒统计数据表明，各断面类圆粒的种类和不同品种的比例存在明显差异。瘤状体形态的空间差异与不同的古地理环境有关。在近岸环境中发育的粗糙的类癌生长模式受到陆源碎屑和陡峭地形的影响，而在近海环境中发育的精细的类癌生长模式受陆地因素的影响较小，并且具有与微生物垫相关的更稳定的沉积过程。