安徽石台奥陶纪弗洛期—大坪期牙形刺多样性的演变

基于安徽石台栗阳柳树亭下、中奥陶统紫台组牙形刺的系统研究，对该地区早奥陶世弗洛期一中奥陶世大坪期牙形刺多样性演变作了初步分析，发现牙形刺的简单分异度在弗洛晚期Oepikodusevae带达到峰值，有17属20种。之后，牙形刺分异度呈下降趋势。演变的总体趋势与湖北宜昌地区同期牙形刺的研究结果一致，其峰值出现的时间（Oepikodusevae带，相当于笔石Didymograptellus eobifidus带上部，Corymbograptusdeflexus带，及Azygograptussuecicus带下部）与华南上扬子区腕足动物宏演化趋势（首次峰值出现在Didymograptelluseob—ifidus带）大体相似，但比三叶虫多样性演变在奥陶纪的首次峰值（出现在Exigraptus clavus带）早，比扬子台地笔石多样性演变的首次峰值（在Acrograptusfiliformis带和Didymograptelluseobifidus带下部）晚。分析显示，该地区早、中奥陶世牙形刺多样性演变与海平面变化存在密切关联。

CONODONT DIVERSIFICATION IN THE ZITAI FORMATION(FLOIAN-DAPINGIAN,LATE EARLY-EARLY MID ORDOVICIAN) OF SHITAI,ANHUI PROVINCE,EAST CHINA

Based on the preliminary research of the conodonts from the Zitai Formation at Liushuting Section,Shitai County,the conodont biodiversity changes during the Floian and the Dapingian are discussed according to the conodont biozones. The Ordovician conodont radiation in the study area got its first acme during the Oepikodus evae Biozone,which was consistent with the macroevolutionary trend of brachiopods in South China. The brachiopod faunas had their first biodiversification acme in the graptolite Didymograp...