GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 88-11
Presentation Time: 10:50 AM


LYU, Zhengyi1, ORCHARD, Michael J.2, GOLDING, Martyn L.3, CHEN, Zhong-Qiang4 and ZHAO, Laishi1, (1)State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Wuhan), No. 388 Lumo Road, Wuhan, 430074, China, (2)Geological Survey of Canada, 605 Robson Street, Vancouver, BC V6B 5J3, Canada, (3)Geological Survey of Canada, 1500-605 Robson Street, Vancouver, BC V6B 5J3, Canada, (4)State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), No. 388 Lumo Road, Wuhan, 430074, China

Lower Triassic conodont biostratigraphy offers one of the most useful and practical tools for developing a high-resolution timescale for the recovery of marine ecosystems after the end-Permian mass extinction, and plays an important role in the stratigraphic correlation between different marine depositional environments.

The Guryul Ravine section in Kashmir is an important section for Lower Triassic stratigraphy, and was once a candidate GSSP section for the Permian-Triassic Boundary (PTB). During the Permian-Triassic (P-T) transition, the section was located on the northern margin of Gondwana, on the southern side of the Palaeo-Tethys inner sea. It has a clear geologic record and abundant fossil fauna, making it an ideal region for biostratigraphic and chronostratigraphic research.

A total of 198 samples were collected from the Guryul Ravine section. A total of 6452 elements including 1621 P1 elements were recovered. Seven conodont zones can be recognized; in ascending order, they are: Hindeodus parvus Zone, Isarcicella staeschei Zone, Neoclarkina krystyni Zone, Neospathodus dieneri Zone, Novispathodus waageni Zone, Novispathodus pingdingshanensis Zone, and Triassospathodus homeri Zone. The PTB is placed within Bed 52 in Unit E2, 80 cm above the base of Unit E2, based on the first occurrence (FO) of Hindeodus parvus. This corresponds to the minimum level for the FO of Hindeodus parvus reported by previous workers. The conodont fossil Novispathodus pingdingshanensis, used to recognize the Smithian-Spathian Boundary interval, was also identified from this section, which is of value for the stratigraphic correlation between high latitude areas and South China.

The conodont sequence erected from the study area compares well with counterparts in South China (e.g. Meishan, Chaohu). Overall, the established conodont zones from the Guryul Ravine section provide a high precision time frame for the study of the coevolution of biology and the environment during the P-T transition, and provide additional data for conodont differentiation and their evolution during this crucial period of Earth history.