重庆中梁山凉风垭二叠-三叠系界线附近牙形类生物地层研究  

CONODONT SUCCESSION ACROSS THE PERMIAN-TRIASSIC BOUNDARY OF THE LIANGFENGYA SECTION,CHONGQING,SOUTH CHINA

作　　者：袁东勋[1] 沈树忠[1] 

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

出　　处：《古生物学报》2011年第4期420-438,共19页Acta Palaeontologica Sinica

基　　金：中科院方向性项目(KZCX2-YW-Q08-4);国家自然基金委的资助

摘　　要：系统研究重庆中梁山凉风垭剖面二叠-三叠系界线附近的牙形类化石及其地层分布,应用样品居群的方法识别出2属7种,并划分为5个牙形类化石带,由下至上依次为:Clarkina changxingensis带,C.yini带,C.meishanensis带,Hindeodus praeparvus带及H.parvus带。确定Clarkina属占优势的居群与Hindeodus属占优势的居群的更替界面位于样品30-1与30-2之间,在此界面之上腕足类、类和珊瑚类等均发生了大量物种消失现象,仅有少量腕足类延续至三叠系底部,这一生物灭绝过程在时间和模式上与煤山剖面的基本一致。二叠系与三叠系的界线位于34层底部Hindeodus parvus分子首现的位置。The taxonomy and stratigraphic distributions of conodonts from the Permian-Triassic boundary beds of the Liangfengya Section at Zhongliang Hill,Chongqing,are described.Seven species in two genera,including Clarkina changxingensis,C.yini,C.meishanensis,Hindeodus typicalis,H.eurypyge,H.praeparvus and H.parvus,are identified and five conodont zones recognized.They are,in ascending order,the Clarkina chang-xingensis Zone,C.yini Zone,C.meishanensis Zone,Hindeodus praeparvus Zone,and H.parvus Zone.Based on their stratigraphic distribution,the changeover from the Clarkina-dominated to the Hindeodus-dominated populations of conodonts occurs in the horizon between samples 30-1 and 30-2.At this horizon,numerous associated brachiopod,fusulinid and coral species also disappeared except for a few small and thin-shelled brachiopods which survived into the basal Triassic.This extinction pattern is generally comparable with that at the Meishan Section in terms of timing and diversity change.The Permian-Triassic boundary at the Liangfengya Section is at the base of Bed 34 as indicated by the first occurrence of the conodont Hindeodus parvus.

关 键 词：牙形类 化石带 二叠-三叠系界线 凉风垭 重庆 

分 类 号：Q915[天文地球—古生物学与地层学]