Lower Triassic conodont sequence in Chaohu, Anhui Province, China and its global correlation

Abstract

The Early Triassic paleogeographical setting of the Chaohu section in China was in a deep part of the Yangtze platform and this has resulted in a rather complete Lower Triassic sequence with rich ammonoid and conodont successions. Three Lower Triassic sections, West Pingdingshan, North Pingdingshan and South Majiashan, have been sampled in detail for a systematic conodont study. Eight conodont zones are recognized; in ascending order these are the zones of Hindeodus typicalis, Neogondolella krystyni, Neospathodus kummeli, Neospathodus dieneri, Neospathodus waageni, Neospathodus pingdingshanensis, Neospathodus homeri, and Neospathodus anhuinensis. These are correlated with the sequences in North America and other areas of the world. The succession provides a good basis for the definition of the global stratotype of the Induan–Olenekian boundary (GSSP), which has been proposed at the base of the Neospathodus waageni Zone in West Pingdingshan. Seven new species are introduced: Neospathodus chaohuensis, N. chii, N. concavus, N. eotriangularis, N. pingdingshanensis, N. posterolongatus, N. tongi, a new subspecies N. waageni eowaageni, and three morphotypes of N. dieneri.