中国科学院南京地质古生物研究所机构知识库

An integrated study of biostratigraphy, microfacies, and stable carbon isotope stratigraphy was carried out on the late Famennian-early Asselian carbonates of the Long'an section in Guangxi, South China. Stable carbon isotope studies in the Long'an section have revealed four major positive shifts of delta C-13 values in the Carboniferous strata in South China. The first shift occurred in the Siphonodella dasaibaensia zone in the Tournaisian, with an amplitude of 4.19 parts per thousand. The second shift occurred near the Visean/Serpukhovian boundary, with an amplitude of 2.63 parts per thousand. The third shift occurred in the Serpukhovian, with an amplitude of 3.95 parts per thousand. The fourth shift occurred in the Kasimovian, with an amplitude of 3.69 parts per thousand. Furthermore, there were several brief positive delta C-13 shifts during the late Famennian to early Tournaisian. All of these shifts can be well correlated globally, and each corresponds to sea-level regressions in South China and Euro-America, indicating increases in ocean primary productivity and global cooling events. Chronologically, the four major positive excursions of delta C-13, together with several brief positive delta C-13 shifts that were observed during the late Famennian to the early Tournaisian, correspond to the well-accepted Glacial I, II, and III events.