Integrated biochemostratigraphy of the Permian-Triassic boundary beds in a shallow carbonate platform setting (Yangou, South China)

• Published in: Global and planetary change Vol. 206; p. 103583
• Main Authors: Zhao, He, Lyu, Zhengyi, Chen, Zhong-Qiang, Algeo, Thomas J., Orchard, Michael J., Liu, Yongsheng, Hu, Zhaochu, Zhang, Lei, Zhang, Xiumei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2021
• Subjects: Carbon isotopes; Conodonts; End-Permian mass extinction; Microfacies; Ooids; Yangtze Platform; End-Permian mass extinction; Yangtze Platform; Ooids; Conodonts; Carbon isotopes; Microfacies
• ISSN: 0921-8181; 1872-6364
• DOI: 10.1016/j.gloplacha.2021.103583

Investigation of the end-Permian mass extinction (EPME) has been greatly facilitated by high-resolution conodont biostratigraphic studies. To date, however, a detailed biostratigraphic framework has been lacking for shallow-marine successions of the Tethys region. In the present study, we analyzed carbonate microfacies, conodont biostratigraphy, and carbonate carbon isotopes of the Yangou Quarry section, a shallow-marine EPME succession that accumulated on an isolated carbonate bank on the northern margin of the Yangtze Platform. Microfacies analysis yielded four facies and 8 microfacies that record a seawater deepening immediately following the EPME. Ooids were abundantly produced during the EPME and earliest Triassic mass extinction (ETME) but were replaced by microbial mats, algae, bivalves, and brachiopods during an earliest Triassic transgression. A total of three conodont zones are recognized from the uppermost Changhsingian to the lowermost Griesbachian, in ascending order, the Hindeodus praeparvus Zone, H. parvus Zone, and Isarcicella staeschei Zone. The EPME and PTB (Permian-Triassic boundary) horizons are marked by the first occurrences of H. praeparvus at 6.18 m and H. parvus at 6.57 m, respectively, above the base of the section. The conodont biostratigraphic framework of the Yangou Quarry section was refined through intercalibration with its δ13Ccarb profile. This section records two discrete negative carbon isotope excursions (CIEs) that are correlative with the EPME and ETME horizons, and that can be correlated with similar CIEs at Meishan D and other PTB sections globally. Our study provides the first integrated, high-resolution biochemostratigraphic framework for a shallow-marine PTB succession in the eastern Tethys region, which will facilitate paleoenvironmental studies of similar facies elsewhere as well as correlations with deeper-water facies. •Uppermost Permian-Lowermost Triassic at Yangou Quarry provides a continuous shallow-marine sequence.•3 conodont zones are established and facilitate definition of EPME and PTB.•Carbonate microfacies reveals a sea-level deepening immediately following the EPME.•>7-m-thick oolitic beds occurs from the uppermost Changhsingian through the lowermost Griesbachian.•Two-episode patterns of negative CIE during the PTB transition that is globally comparable.