湖北兴山古洞口下奥陶统南津关组牙形类及其地层意义  

EARLY ORDOVICIAN CONODONTS FROM THE NANTSINKUAN FORMATION IN XINGSHAN,HUBEI PROVINCE,CHINA AND THEIR STRATIGRAPHIC SIGNIFICANCE

作　　者：闫冠州 刘建波[2] 栾晓聪 吴荣昌 YAN Guanzhou;LIU Jianbo;LUAN Xiaocong;WU Rongchang(State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008;Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education,School of Earth and Space Sciences,Peking University,Beijing 100871)

机构地区：[1]现代古生物学和地层学国家重点实验室,中国科学院南京地质古生物研究所,南京210008 [2]地球与空间科学学院造山带与地壳演化教育部重点实验室,北京大学,北京100871

出　　处：《微体古生物学报》2023年第4期308-316,共9页Acta Micropalaeontologica Sinica

基　　金：国家自然基金委(41672008,42302029);中国科学院战略性先导科技专项(B类)(XDB26000000);中国科学院青年创新促进会(2019308)的资助。

摘　　要：本文分析了湖北兴山古洞口剖面下奥陶统南津关组的牙形类化石。鉴定牙形类4属5种,包含华南下奥陶统常见的Colaptoconusquadraplicatus和Drepanoistoduscostatus。据牙形类产出,识别出Colaptoconus quadraplicatus带。Drepanoistodus costatus的产出表明兴山地区南津关组下部灰岩的时代晚于秭归、宜昌和石门等地的南津关组下部灰岩。基于牙形类化石记录,兴山地区三游洞群和南津关组之间可能缺失了Cordylodus intermedius带(上部)、Cordylodus lindstromi带、Iapetognathus fluctivagus带、Cordylodus angulatus带和Rossodus manitouensis带(部分)。湖北兴山、秭归、宜昌和湖南张家界等地下奥陶统对比表明,各地特马豆克阶下部普遍可识别沉积间断。古洞口剖面南津关组中上部和分乡组中下部可识别LSICE(Late Stairsian Isotopic Carbon Excursion)碳同位素漂移,时代为特马豆克晚期。In this paper,conodonts from the Gudongkou section in Xingshan,Hubei Province,have been studied.Five species belonging to four genera have been identified,including Colaptoconus quadraplicatus,Drepanoistodus costatus,and other species.The conodont distributions allow us to recognize the Colaptoconus quadraplicatus Zone in the Nantsinkuan Formation.Based on the conodont records,a major biostratigraphic gap,including the Cordylodus lindstromi Zone,the Iapetognathus fluctivagus Zone,the Cordylodus angulatus Zone,and the Rossodus manitouensis Zone,has been proposed between the Sanyoudong Group and the Nantsinkuan Formation at the Xingshan area.This gap has also been identified in the Zigui and Yichang areas of Hubei.Integrated conodont biostratigraphy and carbon isotope chemostratigraphy suggested that the previously recognized C1 positive carbon isotope excursion is correlative with the Late Stairsian Isotopic Carbon Excursion(LSICE),which has been used for correlation of the upper Tremadocian.

关 键 词：牙形类 生物地层 沉积间断 南津关组 奥陶系 

分 类 号：P534.42[天文地球—古生物学与地层学] P535[天文地球—地质学] Q913.85[生物学—古生物学]