扬子地台西缘志留系牙形刺研究新进展

Recent progress in the research on the Sinian conodonts from the western margin of the Yangtze platform

笔者详细研究了扬子地台西缘宁蒗 盐边地区志留系岩石地层和牙形刺生物地层的特征 ,该岩系自下而上可建立 3个牙形刺组合带 :①Panderodusgracilis Panderodussimplex组合带 ;②PterospathoduscelloniWalliser组合带 ;③PterospathodusamorphognathoidesWalliser组合带 ;从生物地层学、沉积学和区域对比的角度对地层进行了重新划分 ,分析了PterospathoduscelloniWal liser带和PterospathodusamorphognathoidesWalliser带之间的相互重叠关系 ,并认为其相互关系为渐变演化关系 ,而不是突变关系 ;并对部分重要属种进行了描述。

The Silurian lithostratigraphy and conodont biostratigraphy are focused for the Ninglang Yanbian region on the western margin of the Yangtze platform. Three assemblage zones have been discriminated: Panderodus gracilis Panderodus simplex, Pterospathodus celloni Walliser and Pterospathodus amorphognathoides Walliser zones. The strata in this region are redivided on the basis of biostratigraphy, sedimentology and regional correlation, and some important genera are described in detail. The study of the interrelations shows that there is a gradational rather than sharp contact between the Pterospathodus celloni Walliser and Pterospathodus amorphognathoides Walliser zones.