由于地处低纬度下扬子碳酸盐缓坡台地较深水区，安徽巢湖地区的下三叠统由一系列泥、灰岩旋回层组成，并含有丰富的菊石化石。通过对巢北平顶山和马家山一带上二叠统顶部和下三叠统多条剖面的系统研究，建立了在华南乃至低纬度特提斯地区具有代表性的、以属级分类单位为基础的下三叠统菊石生物地层序列(从下而上)：Ophicerns—Lytophiceras带、Gyronites-Prionolobus带、Flemingites—Euflemingites带、Anasibirites带、Columbites—Tirolites带和Subccdumbites带。在提议的全球印度阶-奥伦尼克阶界线层型候选剖面——巢湖平顶山西坡剖面上，Flemingites-Euflemingites带之底与牙形石Neospathodus waageni首现点比较接近，可以作为本界线主要辅助标志之一。记述采自该区上二叠统顶部及下三叠统，尤其是印度阶-奥伦尼克阶界线附近的一些具有年代地层意义的菊石化石资料，以供该界线层型确定和选择参考。

The uppermost Permian and Lower Triassic are completely exposed in Mt. Pingdingshan and Mt. Ma jiashan , Northwest Chaohu City, Anhui Province, East China, where the Lower Triassic is well developed and composed of the alternations of mudrock and limestone deposited on a deep part of the Lower Yangtze carbonate ramp, containing rich ammonoid fossils. 37 genera and 60 species are recognized from the uppermost Permian and Lower Triassic at the North Pingdingshan Section, West Pingdingshan Section and South Majiashan Section. In addition, many specimens were also collected from the North Majiashan Section and the Guimengguan Section in South Chaohu. A complete Lower Triassic ammonoid zonation can be retrieved in ascending order: Ophiceras Lytophiceras Zone, Gyronites Prionolobus Zone, Flemingites Euflemingites Zone, Anasibirites Zone, Columbites Tirolites Zone and Subcolumbites Zone. The base of the Flemingites Euflemingites Zone is very close to the FAD of conodont Neospathodus waageni at the West Pingdingshan Section, which was proposed as the GSSP of the Induan Olenekian boundary. This paper describes some better preserved ammonoid fossils of biostratigraphic importance with emphasis on those around the Induan Olenekian boundary, plus a few specimens from the uppermost Permian Tapashanites Pleuronodoceras Zone.

Q914.2

国家自然科学基金 (No .40 0 72 0 11，40 3 2 5 0 0 4)，国家重点基础研究发展规划项目 (G2 0 0 0 0 7770 5 )资助