鄂东伍家冲剖面乐平世牙形石生物地层及大隆组的时代  

Lopingian Conodont Biostratigraphy and Age of Dalong Formation at Wujiachong Section,East Hubei Province

作　　者：郝少波 陈龑 黄攀 陈寒超 江海水[1] Hao Shaobo;Chen Yan;Huang Pan;Chen Hanchao;Jiang Haishui(School of Earth Sciences,China University of Geosciences,Wuhan 430074,China;No.3 Geological Party,Xinjiang Bureau of Geology and Mineral Resources,Korla 841000,China)

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074 [2]新疆地矿局第三地质大队,新疆库尔勒841000

出　　处：《地球科学》2021年第11期4057-4071,共15页Earth Science

基　　金：国家自然科学基金项目(Nos.41972033,41830320,41572324)。

摘　　要：大隆组是华南地区乐平世一种重要的较深水沉积.为进一步探讨大隆组沉积的时空分布,选择对鄂东伍家冲剖面吴家坪组和大隆组重点进行了牙形石生物地层研究,此次研究共鉴定出牙形石1属5种,均为Clarkina,并由老到新识别出4个牙形石带:C.guangyuanensis带、C.transcaucasica带、C.orientalis带及C.wangi带.根据牙形石C.wangi的首现,将伍家冲剖面的吴家坪阶-长兴阶界线(Wuchiapingian-Changhsingian boundary,简称WCB)置于第18层底部.根据菊石Ophiceras的首现将伍家冲剖面的二叠系-三叠系界线(Permian-Triassic boundary,简称PTB)置于第20层顶部,仅高于WCB界线0.72 m.牙形石生物地层指示伍家冲剖面大隆组的主体为吴家坪期沉积产物.数个长兴期牙形石带的缺失和极短的长兴阶表明,该剖面长兴阶中上部可能因沉积间断存在缺失.The Dalong Formation is an important deep-water deposition during late Lopingian in South China.For better understanding of the spatial and temporal distribution of the Dalong Formation,detailed conodont biostratigraphic research is conducted from the Wujiaping Formation and Dalong Formation,at the Wujiachong section,East Hubei,South China.As a result,five species of genus Clarkina are recognized.Four conodont zones are established,and they are C.guangyuanensis,C.transcaucasica,C.orientalis and C.wangi zones,in ascending order.The Wuchiapingian-Changhsingian boundary(WCB) is placed at the base of bed 18 of the Wujiachong section based on the first occurrence of conodont C.wangi.The PermianTriassic boundary(PTB) is placed at the top of bed 20 according to the first occurrence of ammonoid Ophiceras,only 0.72 m higher than WCB.Conodont biozones correlation suggests that the Dalong Formation of the Wujiachong section is mainly in age of Wuchiapingian.The absence of the several Changhsingian conodont zones and shorten Changhsingian deposition suggest that the middle and upper parts of Changhsingian of this section may be absent due to a hiatus.

关 键 词：吴家坪阶-长兴阶界线 Clarkina wangi 二叠系-三叠系界线 古生物学 

分 类 号：P52[天文地球—古生物学与地层学]