安徽巢湖平顶山下三叠统牙形石生物地层序列

Lower Triassic Conodont Biostratigraphical Sequence at West Pingdingshan Section, Chaohu, Anhui Province, China

简要介绍安徽巢湖平顶山下三叠统牙形石生物地层研究的最新成果 .对平顶山西坡剖面 112 .8m厚的下三叠统地层所采集的 2 86件牙形石样品 ,经处理后获得 2 870余枚牙形石样本 ,经鉴定共有 11属 5 1种 .这些属分别是Hindeodus,Isarcicella(?) ,Neogondolella ,Neospathodus,Platyvillosus ,Cratognathodus,Parachirognathus,Pachycladina ,Ellisonia ,Aduncodina和Cornudina .牙形石生物地层从老到新可划分为 9个牙形石带 :(1)Hindeodustypicalis-Neogondolellaplanata带 ;(2 )Neogondolellakrystyni带 ;(3)Neospathoduskummeli带 ;(4 )Neospathodusdieneri带 ;(5 )Neospathodusn .sp .C -Neospathodusn .sp .D带 ;(6 )Neospathoduswaageni带 ;(7)Neospathodusn .sp .M带 ;(8)Neospathoduseotriangularis带 ;(9)Neospathodusabruptus-Neospathodushomeri带 .牙形石的组合面貌基本可与国内外其他地区牙形石带相对比 .但其中牙形石 (2 ) ,(3) ,(5 ) ,(7) ,(8)带为巢湖地区首次建立 .在下三叠统菊石带控制下所建立的连续的牙形石分带对全球的三叠系阶的对比具有十分重要的意义 .

The authors provide a brief introduction on the Lower Triassic conodont zonation at West Pingdingshan Section, Chaohu, Anhui Province, China. Rich conodont fossils have been extracted from 172 productive samples in 286 analyzed samples, from the Lower Triassic Yinkeng, Helongshan, and the lower part of Nanlinghu Formation exposed at the section of 112.8 m thick. The extracted 2 187 conodont elements include 51 stratigraphically significant species referable to 11 genera: Hindeodus, Isarcicella(?), Neogondolella, Neospathodus, Platyvillosus, Cratognathodus, Parachirognathus, Pachycladina, Ellisonia, Aduncodina and Cornudina. Nine conodont zones are recognized in ascending order as follows: (1)Hindeodus typicalis-Neogondolella planataZone; (2)Neogondolella krystyniZone; (3)Neospathodus kummeliZone; (4)Neospathodus dieneriZone; (5)Neospathodusn. sp. C-Neospathodusn. sp. D Zone; (6)Neospathodus waageniZone; (7)Neospathodusn. sp. M Zone; (8)Neospathodus eotriangularisZone; (9)Neospathodus abruptus-Neospathodus homeriZone. Zones (2), (3), (5), (7) and (8) are first established and also Neospathodus waageniis reported for the first time from the Yinkeng Formation. Associated with conodonts also occur macrofossils such as ammonoids and bivalves, which confirm the conodont biochronostratigraphy to a certain degree.