江西信丰县铁石口地区二叠—三叠纪牙形石动物群的发现及其地质意义

本文首次报道并描述了江西信丰县铁石口地区的二叠—三叠纪的牙形石动物群;根据牙形石和菊石、双壳类、腕足类,将“铁石口系”划分为三部分:下部(层1～10)、中部(层11～20)、上部(层21～23),它们分别相当于Griesbachian阶、Nammalian阶、Spathian阶。层2～8中发现了二叠纪型和三叠纪化石伴生的混生动物群。三叠系与二叠系之间可暂时以层1厚约3cm的黄白色粘土岩为界线,二系为整合关系。

Discovery of Permian-Triassic Conodont Fauna in Tieshikou Area, Xinfeng, Jiangxi and Its Geological Significance

This paper for the first time reports and describes the Permian-Triassic conodont fauna from the "Tieshikou series" of Tieshikou Area, Xinfeng County, Jiangxi Province. Based on the study of conodonts, ammonoids, bivalves and brachiopods, "Tieshikon series" may be divided into 3 division, the Lower Part (beds 1-10), the Middle Part (beds 11-20) and the Upper Part (beds 21-23), they are equivalent to Early Triassic Griesbachian stage, Nammalian stage and Spathian stage respectively. The mixed-fauna with a coexistence of the Permian-type and Triassic-type fossils were discovered in bed's 2-8. The Permian-Triassic boundary may be placed temporarily at the clay rock (bed 1). The clay bed is yellow and white in color, only 3cm in thickness. The Latest Permian (Changhsingian) Neogondolella changxingensis-Neogondolella deflecta-Palaeofusulina assemblage was found below the clay bed. Anchignathodus cf. parvus-Towapteria scythica -Hollinella tingi-Crurithyris speciosa assemblage was found above the clay bed. The eon-tact between two systems is conformable. The discovery of Neospathodus homeri-N. tri-angularis conodont assemblage in Tieshikou area proves the existence of Spathian there.