Abstract:

Recently, a new Ordovician-Silurian boundary section has been discovered at Nanbazi village of the Honghuayuan Township, Tongzi County, Guizhou Province, South China. In this perfect section, the outcrop of the strata interval, which include the Baota Fm., the Jiancaogou Fm., and the Wufeng Fm., as well as the Longmaxi Fm., in ascending order, exposed pretty well with low dip direction of the beds and abundant of various fossils. The transition interval of the Ordovician-Silurian boundary, from the top of the Guanyinqiao Member of Wufeng Fm. through into the lowermost Longmaxi Fm., can be traced horizontaly about one hundred meters. Moreover, 25 layers of K-bentonite beds have been recognized from the Wufeng Fm. through into the lower part of Longmaxi Fm. With the studies of biostratigraphy and sequence stratigraphy, the present K-bentonite beds have been determined preliminarily that they can be correlated fairly well in high-resolution with those of in Yichang, Hubei Province and other areas. This new section will be a valuable clue for the relevant study focused on the Ordovician-Silurian boundary in South China.

Key words: boundary section, Ordovician, Silurian, South China