【摘要】 湖南桑植县仁村坪剖面二叠—三叠系界线地层连续,菊石动物化石丰富。根据该剖面上二叠统大隆组至下三叠统大冶组底部菊石动物群的分布,自下而上划分为4个菊石带:Araxoceras-Konglingites-Sanyangites带、Sinoceltites带、Pseudotirolites-Rotodiscoceras带和Hypophiceras-Ophiceras-Lytophiceras带。通过对该剖面菊石和牙形石生物地层及其与华南其他剖面的对比可知,Araxoceras-Konglingites-Sanyangites带与牙形石Neospathodu sorientalis带同期,为吴家坪期晚期;Sinoceltites带与牙形石N.subcarinata-N.wangi带同期,为长兴期晚P期;seudotirolites-Rotodiscoceras带与牙形石N.postwangi-N.changxin-gensis带和N.xiangsiensis-N.changxingensis带同期,为长兴期晚期;Hypophiceras-Ophiceras-Lytophiceras带与H.parvus、I.isarcica-I.staesche和N.planata3个牙形石带同期,相当于印度期早期。根据仁村坪剖面菊石Hypophiceras-Ophiceras-Lyto-phiceras带底界的出现位置,将该剖面的二叠—三叠系界线确定在第27a层的中部。更多还原

【Abstract】 At the Rencunping Section,Sangzhi County,Hunan Province,abundant ammonoids were found in the Permian/Triassic(P/T) boundary strata.Based on the distribution of ammonoid fauna from the Upper Permian Dalong Formation to the base of the Lower Triassic Daye Formation,four ammonoid zones are recognized:(1)Araxoceras-Konglingites-Sanyangites zone,(2)Sinoceltites zone,(3)Pseudotirolites-Rotodiscoceras zone,and(4)Hypophiceras-Ophiceras-Lytophiceras zone.Compared with the other sections of South China,the Araxoceras-Konglingites-Sanyangites zone is equal to the conodont Neospathodus orientalis zone,indicating Wujiapingian in age;the Sinoceltites zone is equal to the conodont N.subcarinata-N.wangi zone,indicating the Early Changhsingian;the Pseudotirolites-Rotodiscoceras zone is equal to the conodont N.postwangi-N.changxingensis zone and N.xiangsiensis-N.changxingensis zone,indicating the Late Changhsingian;the Hypophiceras-Ophiceras-Lytophiceras zone is equal to the conodont H.parvus、I.isarcica-I.staesche and N.planata zones,indicating the Early Induan.Based on the first appearance of the Hypophiceras and Ophiceras of the Hypophiceras-Ophiceras-Lytophiceras zone and the correlation of the PTB clays,the P-T Boundary is identified in bed 27a at the Rencunping Section.更多还原