高级检索

    湖北宜昌黄花场下奥陶统弗洛阶上部牙形刺生物地层分带及对比

    Conodont zonation and correlation of upper part of Fuluoian of Lower Ordovician in Huanghuachang section,Yichang, Hubei

    • 摘要: 提要:在宜昌黄花场剖面弗洛期原Oepikodus evae带牙形刺生物地层系统研究的基础上,笔者等讨论了Stolodus stola, L. gladiatus, O. intermedius, Oepikodus communis, Prioniodus honghuayuanensis等重要的多分子器官种分类问题。认为Oepikodus evae带上部时限范围内并未见Oepikodus evae分子,所以与国际地层指南(2000)关于间隔带和延限带的含义相悖。本文通过对黄花场剖面牙形刺样品补充采样、系统检查和厘定原O. evae带内一些牙形石属种分类,分析了牙形刺垂向分布特征。厘定了原Stolodus stola亚带的首现层位,修订了原Oepikodus evae带的含义。在此基础上,以牙形刺带分子首现为标志,将红花园组上部—大湾组下段自下而上划分为4个间隔带和3个亚带。其中4个间隔带为:Prioniodus honghuayuanensis带,O. evae带,Trapezognathus diprion带和Baltoniodus cf. B. triangularis带。其中Prioniodus honghuayuanensis带,Trapezognathus diprion带,Baltoniodus cf. B. triangularis带为新建化石带。并在Trapezognathus diprion和Baltoniodus cf. B. triangularis带时限范围内划分3个亚带:Stolodus stola亚带,Oepikodus intermedius亚带, Microzkodina sp. A.亚带;其中Oepikodus intermedius亚带, Microzkodina sp. A.亚带为新建亚带。由于黄花场剖面中Trapezognathus diprion带-Baltoniodus cf. B. triangularis带时限范围内发现丰富的Reutterodus andinus,Oepikodus intermedius, Juanognathus variabilis等暖水型牙形刺,故此这两个间隔带可为北美中大陆地区同期地层划分对比提供良好的标准。这一划分方案也为进行洲际间不同生物地理分区的精细地层划分对比提供了详实的资料。

       

      Abstract: Abstract:Based on a systematic study of the conodont biostratigraphic data in the former Oepikodus evae zone of the Fuluoian in the Huanghuachang section, the authors discussed several problems concerning the apparatus classification of some important multi-element conodonts: Stolodus stola, L. gladiatus, O. intermedius, Oepikodus communis, Prioniodus honghuayuanensis. The upper part of the former Oepikodus evae zone, without the zonal index fossil Oepikodus evae itself in the Huanghuachang section, conflicts with the definition of interval zone and range zone in International Stratigraphic Guide (2000). Through further collecting conodont samples, checking and revising some of the conodont general and species in the former O. evae zone, the authors analyzed the vertical conodont distribution. The interval from the base of Honghuayuan Formation to the top of Lower Member of Dawan Formation was divided to 4 interval zones: Prioniodus honghuayuanensis zone, O. evae zone, Trapezognathus diprion zone and Baltoniodus cf. B. triangularis zone, and 3 subzones: Stolodus stola subzone, Oepikodus intermedius subzone and Microzarkodina sp.A, in upward succession. The Prioniodus honghuayuanensis zone, Trapezognathus diprion zone and Baltoniodus cf. B. triangularis zone are new zones, and the Oepikodus intermedius subzone and Microzarkodina sp.A are new subzones in this paper. The former Stolodus stola subzone is revised herein. Abundant warm-water fauna conodonts, including Reutterodus andinus,Oepikodus intermedius, Juanognathus variabilis, were found in Trapezognathus diprion zone -Baltoniodus cf. B. triangularis zone in the Huanghuachang section; consequently, these two zones could be serving as a standard for the stratigraphic division and correlation of the relevant strata in central continent of North America. Furthermore, the above bio-stratigraphic division scheme can supply reasonable advice for the precise stratigraphic division and correlation for different biogeographical zones among different continents around the world.

       

    /

    返回文章
    返回