桂东云开地区上奥陶统兰瓮组腕足动物群特征与对比  

Characteristics and Comparison of the Brachiopod Fauna of the Upper Ordovician Lanweng Formation in Yunkai Area,Eastern Guangxi

作　　者：吴琛 牛志军 何垚砚 张雨晨 曾庆銮 柯学[1] 胡昆 王志宏 李出安 Wu Chen;Niu Zhijun;He Yaoyan;Zhang Yuchen;Zeng Qingluan;Ke Xue;Hu Kun;Wang Zhihong;Li Chu’an(Institute of Geological Survey,China University of Geosciences,Wuhan 430074,China;Hubei Key Laboratory of Paleontology and Environment Evolution,Wuhan 430205,China;Wuhan Center,China Geological Survey(Geosciences Innovation Center of Central South China),Wuhan 430205,China;State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008,China;Guangdong Institute of Geological Survey,Guangzhou 510110,China;Guangdong Institute of Marine Geological Survey,Guangzhou 510110,China)

机构地区：[1]中国地质大学地质调查研究院,湖北武汉430074 [2]古生物与地质环境演化湖北省重点实验室,湖北武汉430205 [3]中国地质调查局武汉地质调查中心(中南地质科技创新中心),湖北武汉430205 [4]中国科学院南京地质古生物研究所现代古生物学和地层学国家重点实验室,江苏南京210008 [5]广东省地质调查院,广东广州510110 [6]广东省海洋地质调查院,广东广州510110

出　　处：《地球科学》2024年第9期3228-3240,共13页Earth Science

基　　金：中国地质调查局地质调查项目(Nos.DD20221645,DD20230226);国家自然科学基金项目(Nos.U2244212,41772019).

摘　　要：华南记录了从新元古代至早古生代多期次与超大陆聚合、裂解相关的重大地质事件,然而对于组成华南的两大块体之一的华夏地块目前尚未很好解决最基本的地层序列划分与对比,进而导致其大地构造属性及其与超大陆聚散等关系存在较大争议,因而作为划分时代与对比最直接的地质证据——生物化石对华夏地块研究显得极其重要.本文报道了产于广西岑溪地区上奥陶统兰瓮组三段的腕足类化石,初步鉴定计有13属13种,以Christiania和Dedzetina两属数量最为丰富.动物群总体表现出个体小、壳体薄、丰度高、分异度中等,且以扭月贝类和正形贝类占绝对优势的特点,与区域上非典型叶月贝动物群具有一定的相似性.化石产出于泥岩、粉砂质泥岩中,推测该动物群栖居于以BA4为主体的底域生态位.经腕足类区域对比,确定赋存层位地质时代为晚奥陶世凯迪中‒晚期,为研究区上奥陶统的划分对比以及华南古地理重建增添了古生物学证据.South China has recorded multiple significant geological events related to the assembly and breakup of supercontinents from the Neoproterozoic to the Early Paleozoic.However,the Cathaysia Block,one of the two major blocks constituting South China,still faces unresolved issues in the basic stratigraphic sequencing and correlation,resulting in considerable controversy regarding its tectonic attributes and its relationship with supercontinent cycles.Therefore,the marine fossils,which serve as the most direct geological evidence for stratigraphic division and correlation,is of exceptional importance in the Cathaysia Block.This paper reports the brachiopod fossils from the third member of Upper Ordovician Lanweng Formation in Cenxi area,Guangxi,of which 13 genera and 13 species have been identified.Christiania and Dedzetina are the dominant genera.The fauna generally shows the characteristics of small size,thin shell,high abundance and moderate diversity,and is dominated by Strophomenida and Orthotetida,which is similar to the atypical Foliomena fauna in the region.The fossils are produced in mudstone and silty mudstone.It is speculated that the fauna inhabits in relatively deep water environment,corresponding to BA4.The regional comparison of brachiopods confirms that the age of the occurrence horizon is the Middle-Late Katian of Late Ordovician.This fauna provides paleontological evidence for the division and correlation of the Upper Ordovician in the study area and the paleogeographic reconstruction of the South China Paleoplate.

关 键 词：云开地区 晚奥陶世 腕足类 兰瓮组 华夏地块 地层学. 

分 类 号：P52[天文地球—古生物学与地层学]