Conodont evolution and stratotype sign of carboniferous Tournaisian-Visean boundary in South China  

作　　者：Michel Coen 

机构地区：[1]Louvian University of Belgium, B-1348 Louvian-la-Neuve, Belgium

出　　处：《Science China Earth Sciences》2005年第12期2131-2141,共11页中国科学（地球科学英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant No.40242001).

摘　　要：A stratotype section, boundary point and conodont sign have been recommended for GSSP of the Tournaisian-Visean boundary, based on studies of sectional sedimentology, conodont facies and phylogeneses in South China. Two areas representing margin and inner of the Yangtzi Plate and three sections of different facies were chosen, i.e. the Longdianshan sec-tion of the platform facies in Liuzhou of Guangxi, the Yudong section of the ramp facies in Shidian of Yunnan and the Pengchong section of the basin facies in Liuzhou of Guangxi. Stratigraphic frameworks of two areas were set up by systematical studies of carbonate facies and cycles. Conodont facies-distribution and paleoecologic conditions were researched on statistics of fossil variation and richness, and a kind of planktonic conodont, gnathodids that were widespread, is chosen to select the sign-fossil from it. Seven conodont pedigrees were supplemented or erected by studies of statistics and transitional forms. Conodont evolution in the Early Carboniferous could be divided into three stages, i.e. the Siphonodella stage, the Gnathodus typicus stage and the Gnathodus bilineatus stage. The transform-surface between the later two stages could be put as the Tournaisian-Visean boundary. Finally, this paper proposes that the Pengchong section can be the stratotype candidate of the Tournaisian-Visean boundary, the boundary point be put at the bottom of bed 58 and the stratotype sign of conodont be the first occurrence of Gnathodus praebilineatus of the Gnathodus semiglaber branch.A stratotype section, boundary point and conodont sign have been recommended for GSSP of the Tournaisian-Visean boundary, based on studies of sectional sedimentology, conodont facies and phylogeneses in South China. Two areas representing margin and inner of the Yangtzi Plate and three sections of different facies were chosen, i.e. the Longdianshan sec-tion of the platform facies in Liuzhou of Guangxi, the Yudong section of the ramp facies in Shidian of Yunnan and the Pengchong section of the basin facies in Liuzhou of Guangxi. Stratigraphic frameworks of two areas were set up by systematical studies of carbonate facies and cycles. Conodont facies-distribution and paleoecologic conditions were researched on statistics of fossil variation and richness, and a kind of planktonic conodont, gnathodids that were widespread, is chosen to select the sign-fossil from it. Seven conodont pedigrees were supplemented or erected by studies of statistics and transitional forms. Conodont evolution in the Early Carboniferous could be divided into three stages, i.e. the Siphonodella stage, the Gnathodus typicus stage and the Gnathodus bilineatus stage. The transform-surface between the later two stages could be put as the Tournaisian-Visean boundary. Finally, this paper proposes that the Pengchong section can be the stratotype candidate of the Tournaisian-Visean boundary, the boundary point be put at the bottom of bed 58 and the stratotype sign of conodont be the first occurrence of Gnathodus praebilineatus of the Gnathodus semiglaber branch.

关 键 词：Tournaisian-Visean boundary  global stratotype  CONODONT evolution. 

分 类 号：P534.45[天文地球—古生物学与地层学]