广西全州地区晚泥盆世牙形石和腕足类生物地层

    Upper Devonian conodonot and brachiopod biostratigraphic in Quanzhou area, Guangxi

    • 摘要: 广西东北部泥盆系发育良好,化石丰富,对研究中国华南地区泥盆纪生物地层具有重要意义。对广西全州地区东山剖面上泥盆统佘田桥组、锡矿山组和孟公坳组进行了系统的化石采集及室内分析,共获得104枚牙形石化石和34件腕足类化石。经鉴定,牙形石共21属19种,腕足类化石共6属9种。根据化石种属在东山剖面上的分布,自下而上可划分出8个牙形石带:Icriodus brecis带,Schmidtognathus hermanni-Polygnathus cristatus带,Schmidtognatus wittekindtii带,Palmatolepis linguiformis带,Palmatolepis triangularis带,Palmatolepis rhomboidea带,Icriodus cornutus带和Palmatolepis gracilis manca-Rhodalepis polylophodontiformis带,指示研究区内佘田桥组、锡矿山组、孟公坳组分别对应国际年代地层单位的弗拉斯阶上部、法门阶下部和法门阶中上部,并通过Palmatolepis triangularis的首现确立了该地区弗拉斯阶和法门阶(F-F)的界线;在东山剖面共划分出2个腕足类组合带:弓石燕(Cyrtospirifer)组合带和云南贝(Yunnanella)-帐幕石燕(Tenticosififer)组合带,它们分别与东山剖面中牙形石Palmatolepis falsiovalis-Palmatolepis linguiformis带、Palmatolepis rhomboidea-Palmatolepis marginifera带对应。

       

      Abstract: The Devonian strata are developed in northeastern Guilin area, where there exist large quantities of fossils, which are of great significance for studying the Devonian biostratigraphy in southern China. The authors collected and studied conodonts and brachiopods from Changlongjie Formation, Xikuangshan Formation and Menggongao Formation in the Middle-Upper Devonian strata of the study area and obtained 104 pieces of conodonts and 34 brachiopod fossils. 20 species of 21 genus of conodonts as well as 9 species of 6 genus of conodonts were identified. According to the important conodonts fossils, 8 conodont zones were set up from the bottom to the top in the study area:Icriodus brecis Zone, Schmidtognathus hermanni-Polygnathus cristatus Zone, Schmidtognathus wittekindtii Zone, Palmatolepis linguiformis Zone, Palmatolepis triangularis Zone, Palmatolepis rhomboidea Zone, Icriodus cornutus Zone, Palmatolepis gracilis manca-Rhodalepis polylophodontiformis Zone, which indicates that Changlongjie Formation, Xikuangshan Formation and Menggongao Formation correspond to the upper part of Frasnian stage, the bottom part of Famennian stage and the middle and upper part of Famennian stage, respectively. In addition, the authors indicated Frasnian stageFamennian stage boundary in the study area according to the first appearance of Palmatolepis triangularis, 2 combinations were established in the study area:Cyrtospirifer Zone and the Yunnanella-Tenticosififer Zone, which correspond to Palmatolepis falsiovalis Zone, Palmatolepis linguiformis Zone, Palmatolepis marginifera.

       

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