华南贵州罗旬纳水剖面宾夕法尼亚亚系各阶之界线

贵州罗甸纳水剖面是研究宾夕法尼亚亚系牙形刺和各阶界线的良好剖面.经详细研究,从石炭系中间界线至石炭-二叠系界线,一个新的牙形刺序列为Gnathodus bilineatus bollandensis(密西西比亚系顶部),Declinog-nathodus noduliferus, Idiognathoides sulcatus sulcatus, Id. sinuatus, Id. corrugatus-Id. pacificus, Neognatho-dus symmetricus, Idiognathodus primulus-Neognathodus symmetricus, Idiognathodus primulus-Neognathodus bassleri, Idiognathoides sulcatus parva, Streptognathodus expansus, Idiognathoides ouachitensis, Diplognatho-dus coloradoensis, Di. ellesmerensis, Gondolella donbassica-Go, clarki, Idiognathodus podolskensis, Swadelina subexcelsa, Sw. makhlina-Sw, nodocarinata, Idiognathodus sagittalis, Streptognathodus cancellosus, St. graci-lis, St. guizhouensis, Idiognathodus simulator, I. nashuiensis, Streptognathodus firmus, St. tenuialveus, St. wabaunsensis和St. isolatus(二叠系)等带.Declinognathodus noduliferus和Streptognathodus isolatus的首次现分别代表宾夕法尼亚亚系和二叠系之底;Diplognathodus ellesmerensis, Idiognathodus sagittalis和J. simula-tor的首现则可分别代表莫斯科阶(Moscovian),卡西莫夫阶(Kasimovian)和格舍尔阶(Gzhelian)之底界.作者较为详细讨论了巴什基尔阶与莫斯科阶以及卡西莫夫阶与格舍尔阶之界线,并认为以Diplognathodus ellesmerensis的首现作为巴什基尔阶(Bashkirian)与莫斯科阶之界线足目前最合适的标志.Diplognathodus ellesmerensis是一易于识别、分布广泛及层位稳定的牙形刺种,其产出又十分接近巴什基尔阶与莫斯科阶的传统界线,因此是划分此界线的良好标志.作者拟推荐纳水剖面为莫斯科阶底界之候选层型剖面,这一界线详细的工作正在大量采样分析和深入研究中,成果将在以后陆续发表.