LAUSR

The Bancheng Formation exposed along the Shiti Reservoir nearby Bancheng Town, Qinfang Basin, southern Guangxi, is mainly composed of thin-bedded chert. The radiolarian assemblages in the studied section suggest it was a pelagic setting and the age of the Bancheng Formation is Late Carboniferous to Early Permian. The detrital zircon U-Pb ages from the section are characterized by a Permian peak at ~282 Ma. Detrital zircon provenance analysis suggests that the Permian detrital zircons in the Bancheng Formation were likely from volcanic-magmatic arc rocks related to the subduction of the Paleo-Tethyan Ocean. The long-lived deposition (from Upper Devonian to Middle Permian, about 125 Ma) of the radiolarian cherts in the Qinfang Basin was comparable with that deposited in Ailaoshan Ocean. The radiolarian assemblages in Qinfang Basin show a Tethyan affinity. Together with the Permian subduction-related arc volcanic rocks and the E-MORB type basalts to the northwest of the study area, our data support the existence of a Permian arc-related basin in the Qinfang area.