贵州熊家场寒武系梅树村阶磷块岩中小壳动物化石微结构特征及与成磷关系分析

MICRO-STRUCTURAL CHARACTERISTICS OF THE SMALL SHELLY FOSSILS AND THE RELATIONSHIP WITH FORMING PHOSPHORUS IN CAMBRIAN MEISHUCUN STAGE PHOSPHORITES,XIONGJIACHANG,GUIZHOU

寒武纪早期是全球小壳动物化石大幅射的时期,贵州寒武纪初期磷块岩中就含有大量种类丰富的小壳动物化石,而前人对其研究多局限于外观形态的描述,对其微观结构方面的研究较少。文中通过对贵州熊家场地区磷块岩中小壳动物Turcutheca,Paracircotheca,Loculitheca zhijinensis以及Protospongia化石进行电子显微镜观察,描述其显微结构特征。并对Turcutheca,Paracircotheca进行重点生物结构研究,探讨其壳体形态、生长发育方式。通过对小壳动物化石壳体进行SEM-EDS分析,确定组成壳体主要成分为碳氟磷灰石。另外,对化石Turcutheca内核填充部分、壳壁、围岩进行EDS能谱分析,及其元素特征进行对比,初步探讨生物体与成磷之间的关系,认为寒武纪早期小壳动物的繁盛对同期磷块岩的形成起到了至关重要的作用。

The early period with the Cambrian is the most abundant global small shelly fossils. In the early Cambrian period of Guizhou, phosphate rock contains a large number of and rich species of small shelly fossils, and the predecessors limited their research to the description of appearance, and less research on the microstructure. Through observing small shelly fossils of phosphate rock in the Xiongjiaehang of Guizhou with electron microscope, such as Turcutheca, Paracircotheca, Loculitheca zhijinensis and Protospongia fossils, the authors describe the characteristics of microstructure. This paper mainly studies the biological structure of Turcutheca and Paracircotheca and discusses their shell morphology and growth and development. Through SEM-EDS analysis of the fossil shells of sma｜l shelly fossils, we can be sure that. the main components of the shell are fluorocarbon apatite. In addition, through making EDS analysis of the filling part, shell wall and surrounding rocks of the fossil Turcutheca kernel and making a contrast of element property, and the relationship between the organism and the phosphorus is preliminarily discussed, and it is considered that the prosperity of the early small shelly animals in the early Cambrian plays an important role in the formation of phosphate rocks in the same period.