二叠系乐平统底界新“金钉子”剖面牙形类序列  

Conodont succession from the new GSSP section of the basal Lopingian(Upper Permian)

作　　者：袁东勋 张华[3] 郑全锋[3] 李乾 张以春[3] 侯章帅 戴昱 沈树忠 YUAN Dongxun;ZHANG Hua;ZHENG Quanfeng;LI Qian;ZHANG Yichun;HOU Zhangshuai;DAI Yu;SHEN Shuzhong(School of Resources and Geosciences,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;State Key Laboratory for Mineral Deposits Research,Frontiers Science Center for Critical Earth Material Cycling,School of Earth Sciences and Engineering,Nanjing University,Nanjing,Jiangsu 210023,China;Key Laboratory of Palaeobiology and Petroleum Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing,Jiangsu 210008,China;Guangxi Institute of Regional Geological Survey,Guilin,Guangxi 541003,China)

机构地区：[1]中国矿业大学资源与地球科学学院,江苏徐州221116 [2]南京大学地球科学与工程学院,内生金属矿床成矿机制研究国家重点实验室,关键地球物质循环前沿科学中心,江苏南京210023 [3]中国科学院南京地质古生物研究所,古生物学与油气地层应用重点实验室,江苏南京210008 [4]广西壮族自治区区域地质调查研究院,广西桂林541003

出　　处：《地质学报》2024年第10期3002-3016,共15页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42272031,42261144668,42072013);江苏省重大科技开放合作平台建设项目(编号BZ2023068)联合资助的成果。

摘　　要：二叠系乐平统底界原全球界线层型剖面和层型点(俗称“金钉子”)确立在我国华南广西来宾蓬莱滩剖面,但由于大藤峡水利枢纽工程的建设,目前,蓬莱滩剖面已经长期被淹没于水面之下。近期,乐平统底界新的“金钉子”被正式批准确定在蓬莱滩原剖面附近的蓬莱滩新剖面,依据牙形类化石Clarkina postbitteri的首现层位作为新界线标准。鉴于乐平统底界新“金钉子”的层型剖面、界线层位以及界线标志物种均有改变,本文详细报道了蓬莱滩新剖面的牙形类动物群及它们的产出层位。基于对该剖面茅口组顶部至合山组底部高分辨率的牙形类样品研究,共识别出不少于5属7种,包括Clarkina dukouensis、C.postbitteri、Hindeodus sp.、Iranognathus sp.、Jinogondolella granti、J.xuanhanensis和Sweetognathus fengshanensis等,并对重要属种进行了详细的对比讨论。该剖面由下至上可划分出4个牙形类化石带Jinogondolella xuanhanensis带、J.granti带、Clarkina postbitteri带和C.dukouensis带,并确定C.postbitteri精确的首现层位位于蓬莱滩新剖面第n6L层的底面。蓬莱滩新剖面的牙形类动物群也很好地解释了Jinogondolella granti作为Clarkina postbitteri直接祖先种的唯一可能性。The original Global Stratotype Section and Point(GSSP)for the base boundary of the Lopingian Stage(Permian)was defined at the Penglaitan section in Laibin of Guangxi,South China.Unfortunately,this section has been permanently submerged due to the construction of a hydroelectric dam.Recently,a new GSSP for the Lopingian base,defined by the first appearance datum(FAD)of the conodont Clarkina postbitteri within the lineage Jinogondolella granti→Clarkina postbitteri→C.dukouensis at the new Penglaitan section,which is nearby the original Penglaitan section,has been formally ratified by the International Commission on Stratigraphy(ICS)of the International Union of Geological Sciences(IUGS).This paper presents in detail the conodont biostratigraphy from the new Penglaitan section.Based on high-resolution conodont sampling,at least seven species belonging to five genera have been identified from the uppermost part of the Maokou Formation to the base of the Heshan Formation.These include Clarkina dukouensis,C.postbitteri,Hindeodus sp.,Iranognathus sp.,Jinogondolella granti,J.xuanhanensis,and Sweetognathus fengshanensis.The taxonomy and lineage of key species within the Clarkina to Jinogondolella transition are discussed,confirming that Jinogondolella granti is the direct ancestor of Clarkina postbitteri.Four conodont zones,in ascending order,are recognized in this section:the Jinogondolella xuanhanensis Zone,the J.granti Zone,the Clarkina postbitteri Zone,and the C.dukouensis Zone.The FAD of the index conodont species C.postbitteri occurs at the base of Bed n6L,which has been redefined as the base-Lopingian GSSP.

关 键 词：全球界线层型 乐平统 牙形类 蓬莱滩新剖面 吴家坪阶 

分 类 号：Q913.85[天文地球—古生物学与地层学] P534.46[生物学—古生物学] P535