Ammonoid succession across the Wuchiapingian/Changhsingian boundary of the northern Penglaitan Section in the Laibin area, Guangxi, South China

摘要

A detailed examination has been made of the Lopingian (Late Permian) ammonoid succession across the Wuchiapingian/Changhsingian boundary of the northern Penglaitan Section in the Laibin area, South China. Five ammonoid interval zones were identified via bed-by-bed collection: the Prototoceras-Konglingites, Etoushanoceras-Jinjiangoceras, Shevyrevites, Penglaites and Pleuronodoceras-Rotodiscoceras zones, in ascending order. The lower three zones, located in the upper part of the Heshan Formation, are all of Wuchiapingian age in terms of the associated conodonts, whereas the Penglaites Zone, which crosses the lithologic boundary between the Heshan and Talung formations, and the uppermost zone in the lower part of the Talung Formation are of Changhsingian age. Ammonoid faunal turnover, from otoceratoid-dominated to Xenodiscoid-dominated faunas, occurred between the Etoushanoceras-Jitijiangoceras and Shevyrevites zones. This horizon is slightly lower than the Wuchiapingian/Changhsingian boundary, which is located between the Shevyrevites Zone and the Pen glaites Zone of the northern Penglaitan Section in the Laibin area, South China. Copyright (C) 2010 John Wiley & Sons, Ltd.