A new Rhaetian plant assemblage from Zilanba, the northern Sichuan Basin, South China

Abstract

Triassic and Jurassic strata are thick and widely distributed in the Sichuan Basin, South China. In particular, the continental Upper Triassic Xujiahe Formation is well-exposed in this region, yielding rich assemblages of fossil plants. Here, a new Rhaetian fossil assemblage is reported from Zilanba in the Guangyuan area, northern Sichuan Basin. In this locality, 29 species of fossil plants belonging to 17 genera have been newly collected and identified within Member III of the Xujiahe Formation. Based on the floral assemblages and previous magnetostratigraphic and palynostratigraphic studies, the host strata are considered Rhaetian in age. This flora in the Guangyuan area is dominated by Cycadales and Bennettitales but also contains abundant ferns and less common sphenopsids, conifers and other gymnosperms. The occurrence of some climate-diagnostic plants, such as Dipteridaceae, Anthrophyopsis and Ptilozamites, indicate that this area experienced a humid and warm tropical or subtropical climate during the Rhaetian.