“赫南特阶”和奥陶系—志留系界线的厘定

根据对湖北宜昌王家湾、黄花场、分乡以及新近发现的远安苟家垭奥陶系与志留系界线剖面生物地层、层序地层和化学地层的综合研究将该区最晚奥陶纪到最早志留纪的化石带自下而上重新厘定为Nankinolithus带,Dicellograptus complexus带,Paraorthograptus pacificus带,Nor-malograptus bohemicus-N.extraordinarius带,Hirnantia-Kinnella带,Glyptograptus? persculp—tus带,Akidograptus ascensus带,Parakidograptus acuminatus带和Orthograptus vesiculosus带,其中Paraorthograptus pacificus带可分为Pararetiograptus sinensis亚带,Tangyagraptus typicuas和Diceratograptus mirus亚带。指出目前尚无可靠证据证明国际奥陶系与志留系界线层型剖面,即英格兰Dob’s Linn剖面P. acuminatus带底部与该种首次出现...