K-bentonite beds and high-resolution integrated strati- graphy of the uppermost Ordovician Wufeng and the lowest Silurian Longmaxi formations in South China  

作　　者：苏文博 何龙清 王永标 龚淑云 周湖云 

机构地区：[1]School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China [2]Yichang Institute of Geology and Mineral Resources, China Geological Survey, Yichang 443003, China [3]Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China [4]Test Center, China University of Geosciences, Wuhan 430074, China

出　　处：《Science China Earth Sciences》2003年第11期1121-1133,共13页中国科学（地球科学英文版）

基　　金：the National Natural Science Foundation of China(Grant No.49802002);the State Key Project of Sequence Stratigraphy and Earth Rhythms ; the Lab of Earth Surface Systems of Hubei Province.

摘　　要：More than 20 K-bentonite beds were discovered from the Wufeng Formation and the lowest Longmaxi Formation in two sections, both adjacent to the Ordovician-Silurian (O-S) bound-ary and located in Tongzi, Guizhou Province and Yichang, Hubei Province, some 500 km apart from each other in South China. This indicates that many volcanic eruptions occurred near the southeast margin of the Yangtze Platform between the latest Ordovician and the earliest Silurian. Mainly through biostratigraphic and sequence stratigraphic studies, it was found that almost all these far-apart K-bentonite beds may be correlated with each other. This is the first time that a succession of volcanic ash deposits with high potential of correlation was discovered within a strata interval on the main platforms of China. Therefore, these K-bentonite beds may afford ex-cellent event-marker beds helpful to high-resolution research in integrated stratigraphy as well as other lines of research on the O-S boundary in South China.More than 20 K-bentonite beds were discovered from the Wufeng Formation and the lowest Longmaxi Formation in two sections, both adjacent to the Ordovician-Silurian (O-S) boundary and located in Tongzi, Guizhou Province and Yichang, Hubei Province, some 500 km apart from each other in South China. This indicates that many volcanic eruptions occurred near the southeast margin of the Yangtze Platform between the latest Ordovician and the earliest Silurian. Mainly through biostratigraphic and sequence stratigraphic studies, it was found that almost all these far-apart K-bentonite beds may be correlated with each other. This is the first time that a succession of volcanic ash deposits with high potential of correlation was discovered within a strata interval on the main platforms of China. Therefore, these K-bentonite beds may afford excellent event-marker beds helpful to high-resolution research in integrated stratigraphy as well as other lines of research on the O-S boundary in South China.

关 键 词：K-BENTONITE bed  event-marker  HIGH-RESOLUTION INTEGRATED stratigraphy  Ordovician-Silurian Boundary  Wufeng & Longmaxi formations  Yangtze Platform. 

分 类 号：P539[天文地球—古生物学与地层学]