The Relationship between the “Green-Bean Rock” Layers and Conodont Chiosella timorensis and Implications on Defining the Early–Middle Triassic Boundary in the Nanpanjiang Basin, South China  

作　　者：Chunbo Yan Haishui Jiang Xulong Lai Yadong Sun Bo Yang Lina Wang 

机构地区：[1]State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences [2]Wuhan Center of Geological Survey [3]School of Earth Sciences, China University of Geosciences

出　　处：《Journal of Earth Science》2015年第2期236-245,共10页地球科学学刊（英文版）

基　　金：supported by 973 Program (No. 2011CB808800);the Natural Science Foundation of China (Nos. 41172024, 41272044, 41402005);the "111" project (No. B08030);the ‘Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan);the State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (No. GBL11202)

摘　　要：The Triassic ＂Green-bean Rock＂ （GBR） layers were widely recognized around the Early-Middle Triassic boundary interval in the Nanpanjiang Basin, South China. To determine the precise relationship between the GBR layers and the first appearance datum （FAD） of the conodont Chiosella timorensis, four Lower-Middle Triassic sections from the Nanpanjiang Basin, including the Gaimao, Bianyang lI, Zuodeng and Wantou sections have been studied in detail. Detailed conodont biostratigraphy convinces us that there is no exact temporal relationship between the GBR layers and first occurrence of Ch. timorensis. Moreover, the numbers of the GBR layers are different from the place to place within the Nanpanjiang Basin, and the time span of the GBR layers was much longer than previously estimated. Global correlations show that the FAD of Ch. timorensis is contemporaneous basinwide and worldwide and more suitable marker defining the Olenekian-Anisian boundary （Early-Middle Triassic boundary） than any other proxies.The Triassic ＂Green-bean Rock＂ （GBR） layers were widely recognized around the Early-Middle Triassic boundary interval in the Nanpanjiang Basin, South China. To determine the precise relationship between the GBR layers and the first appearance datum （FAD） of the conodont Chiosella timorensis, four Lower-Middle Triassic sections from the Nanpanjiang Basin, including the Gaimao, Bianyang lI, Zuodeng and Wantou sections have been studied in detail. Detailed conodont biostratigraphy convinces us that there is no exact temporal relationship between the GBR layers and first occurrence of Ch. timorensis. Moreover, the numbers of the GBR layers are different from the place to place within the Nanpanjiang Basin, and the time span of the GBR layers was much longer than previously estimated. Global correlations show that the FAD of Ch. timorensis is contemporaneous basinwide and worldwide and more suitable marker defining the Olenekian-Anisian boundary （Early-Middle Triassic boundary） than any other proxies.

关 键 词：Early-Middle Triassic boundary Green-bean Rock Chiosella timorensis Nanpanjiang Basin. 

分 类 号：P534.51[天文地球—古生物学与地层学] TV12[天文地球—地质学]