华南中泥盆世艾菲尔期浅海相四射珊瑚的组合特征和古生物地理区系

THE ASSEMBLAGE SEQUENCES AND BIOGEOGRAPHIC PROVINCES OF THE EIFELIAN RUGOSE CORALS IN NEAR-SHORE FACIES FROM SOUTH CHINA

虽然在华南中泥盆世艾菲尔期(Eifelian)较深水或斜坡相地层中产有许多国际标准的牙形类带化石,但在广阔的浅海相地层中却很难寻觅到其踪影。华南浅海相沉积地区是否缺失艾菲尔阶?在野外众多剖面的实地考察中表明,从下泥盆统埃姆斯阶到中泥盆统吉维特阶都是连续沉积,中间并没有发现地层的缺失或间断现象。浅海相的艾菲尔阶与其上覆的吉维特阶和下伏的埃姆斯阶都是连续沉积,说明可能是由于海水太浅,不太适合那些国际标准分子的生存而已。艾菲尔期中期末发生一次生物灭绝事件(Mid-Eifelian event),favositids,heliolitids和许多古老类型的珊瑚在地球上灭绝。华南艾菲尔期四射珊瑚可以划分成下、上两个完全不同的组合:1)Utara-tuiasinen sis-Sociop hyllum minor组合(牙形类partitus带—costatus带);2)Columnaria spinosa-Dendrostella praerhenana组合(牙形类australis带—kocklianus带)。

The Eifelian Stage has been divided from bottom to top into four conodont zones： partitus, costatus, australis and kocklianus by SDS. However, we have rarely found the above-mentioned standard zonation conodonts in the near-shore deposits from South China though we have found some important Devonian organism groups such as conodonts, ammonoids, tentaculites and others in the pelagic deposits of South China.