贵州清镇寒武系底部首次发现埃迪卡拉型盘状化石:生物学、埋藏学及其古地理意义  

First discovery of the Ediacaran-type discoid fossils at the bottom of Cambrian in Qingzhen,Guizhou:Biological,taphonomic and palaeogeographic implications

作　　者：高磊 杨瑞东[1,2] 高军波[1,2] 倪莘然 李鑫正 彭柔 刘林林 高川黔 吴桐 GAO Lei;YANG Ruidong;GAO Junbo;NI Xinran;LI Xinzheng;PENG Rou;LIU Linlin;GAO Chuanqian;WU Tong(College of Resources and Environmental Engineering,Guizhou University,Guiyang,550025;Key laboratory of Karst Georesources and Environment,Ministry of Education Guizhou University,Guiyang,550025;Guizhou Research Center for Palaeontology,Guiyang,550025;Resource and Environmental College,Henan University of Engineering,Zhengzhou,450000)

机构地区：[1]贵州大学资源与环境工程学院,贵阳550025 [2]贵州大学喀斯特地质资源与环境教育部重点实验室,贵阳550025 [3]贵州省古生物研究中心,贵阳550025 [4]河南工程大学资源与环境学院,郑州450000

出　　处：《地质论评》2025年第2期635-654,共20页Geological Review

基　　金：国家重点研发计划项目(编号:2023YFC2906604);国家自然科学基金资助项目(编号:41890841,42163006);贵州省科技支撑资助项目(编号:黔科合支撑[2024]一般128)的成果。

摘　　要：盘状化石是埃迪卡拉纪(Ediacaran,≈震旦纪)最早被描述的生物分子,也是全球埃迪卡拉生物群最重要的组成部分,对于重建埃迪卡拉纪—寒武纪过渡时期的生态系统,了解“寒武纪大爆发”时期生物的早期演化至关重要。Aspidella是埃迪卡拉纪圆盘状化石的一个形态属,也是全球分布的埃迪卡拉纪沉积物中的典型化石。笔者等描述了在贵州清镇埃迪卡拉系—寒武系桃子冲组下部硅质岩中,首次被记录的埃迪卡拉纪疑似Aspidella盘状化石(cf.Aspidella),表现为以同心圆环、中央凸起和凹痕为特征的圆盘,三维结构扫描观察到其明显的阶梯状圈层变化。笔者等倾向于认为桃子冲组cf.Aspidella作为底栖软躯体叶状生物的固着器,其内部沉积物是在海水正常沉积作用下形成的,并发现了含Fe、Al物质的固着器生物膜碎片。证实生物固着器官受到微生物席的影响优先保存,而茎干和复叶却消失不见,黏土和砂砾的差异压实作用导致死亡后的生物固着器的球壁上产生了阶梯状的轮廓。结合贵州清镇埃迪卡拉系—寒武系桃子冲组地层中出现的生物组合与华北、柴达木地块的埃迪卡拉纪生物地层的相似性,以及埃迪卡拉纪到寒武纪过渡时期的全球古地理格局,华南板块由中纬度持续地向华北、柴达木地块所处的低纬度区域漂移,环境的改变可能是导致埃迪卡拉纪晚期生物分子在华南寒武系地层中得到种群延续的诱导因素,并进一步扩展了经典埃迪卡拉型化石在时间和空间的分布。Objectives:Discoid fossils are the earliest and the most important components in the Ediacaran biota.Aspidella,a disk-like Ediacaran form genus,is a typical fossil in Ediacaran sediments distributed worldwide.This article describes the Ediacaran biota element Aspidella disc-like fossil(cf.Aspidella)which is here first recorded in siliceous rocks at the bottom of the Taozichong Formation of the Ediacaran–Cambrian transitional strata in Qingzhen of Guizhou,and studies its biological and ecological characteristics,as well as its preservation mechanism in the Cambrian strata.This is crucial for the rebuilding of the ecosystem during the Ediacaran–Cambrian transition and for the understanding of the early evolution of organisms during the“Cambrian Explosion of life”.Methods:In this article,the 3D view image of fossils was taken using the Leica-DVM63D microscopy system.And the micromorphological observations and microchemical analysis of fossils were performed using a HITACHI-SU8010 scanning electron microscope(SEM)equipped with an energy dispersive spectrometer(EDS).The mineral composition of the fossil was analyzed by whole rock X-ray diffraction(XRD,PANalytical B.V.)and Raman spectroscopy(LabRAM HR Evolution).Results:Ediacaran biota element Aspidella disc-like fossil(cf.Aspidella)which is here first recorded in siliceous rocks at the bottom of the Taozichong Formation of the Ediacaran–Cambrian transitional strata in Qingzhen of Guizhou as a disc characterized by concentric ring,central bulge and indentation.A 3D image of the Aspidella fossil shows obvious step-like layer changes.In summary,according to the SEM—EDS analysis,combined with the in situ Raman spectroscopy and the XRD analysis,cf.Aspidella is the morphological remains of holdfasts of organisms on the seabed,rather than geological sedimentary phenomena such as solid fossils or gas escape structures.Its special ring structures are formed by the rapid filling of holdfasts by sand and clay minerals during the process of burial and mutation.Conclus

关 键 词：cf.Aspidella 固着器官 埃迪卡拉生物分子 埋藏学 震旦纪 寒武纪 

分 类 号：G63[文化科学—教育学]