Revised age of the Fengcheng Formation, Junggar Basin, China: Global implications for the late Paleozoic ice age

Abstract

The age of the Fengcheng Formation in the Junggar Basin, China, is key to understanding the effects of the late Paleozoic ice age (LPIA) on the Northern Hemisphere. Here we present zircon UPb age and Hf isotope data, along with stable CO isotoope data, and discuss the implications of these for the LPIA. The age of the Fengcheng Formation is constrained to ca. 300 Ma (i.e., Kasimovian–Asselian), which is at the Carboniferous–Permian boundary. Most of the Fengcheng Formation was deposited during the late Carboniferous warming period and partly during the LPIA Glacial III/P1. The C isotope data and occurrence of evaporites sensitively record the LPIA. The Hf isotope data record the complete closure of the paleo-Junggar Ocean at ca. 300 Ma. The hydrologically restricted Junggar Basin was likely affected by the LPIA due to an atmosphere–hydrological response. The complete closure of the paleo-Junggar Ocean coincided broadly with the beginning of early Permian glaciation and hints at a subtle relationship between continental amalgamation and glaciation.