Spheroidal Fossils From The Terreneuvian Yanjiahe Formation In Yichang,Hubei

The phosphatized spheroidal fossils of Early Cambrian small shelly fossils are a group of common and multi-source problematic fossils,including algae,acritarches,animal embryos and other biological types.Herein the spheroidal fossils from Yanjiahe Biota(Cambrian Terreneuvian)in Yichang,Hubei province are selected as the main research objects to study the fossil morphology and discuss the genetic relationship.The main conclusions are as follows:1.Eight types of spheroidal fossils were identified,such as Olivoodes pearformis,Archaeoodes granulates,A.kuanchuanpuensis,Aetholicopalla adnata,folded spheroidal fossils,pseudomorphs spheroidal fossils of microorganisms,porous spheroidal ones and split spheroidal fossils.These materials supplement the deficiency of the study on spheroidal fossils in Yanjiahe Biota,and provide the carrier of research for exploring the diversity of spheroidal fossils and paleoenvironment change.2.Based on the previous research data and combined with fossil materials herein,it is considered that Olivooides may contain a variety of animal embryos.Archaeooides,folded spheroidal fossils and split spheroidal ones may be the resting animal embryos,but their exact biological affinities still need more anatomical evidences.3.Aetholicopalla adnata,a spiny spheroidal fossil,is firstly reported in Yanjiahe Formation.According to the complex multi-layer wall structure,A.adnata is placed in algal fossils.The Cope's rule of Aetholicopalla adnata may be related to the enrichment of phosphorus in the Cambrian marine environment.4.Microsphere polymer is a pseudomorphs spheroidal fossils of microorganisms formed by the degradation process of spheroids.The discovery of microbial pseudospherical fossils with sphalerite mineralized coating indicates that hydrothermal fluid involved in the burial process of fossils,which is the late metasomatic origin.