Carboniferous-Permian high-resolution conodont biostratigraphy and paleoclimate change in North China

Abstract

The Carboniferous-Permian transition is a critical period for the Late Paleozoic Ice Age that evolved from an acme to the subsequent demise with the initiation of long-term drying in low latitudes. During this time interval, extensive epicontinental deposition occurred in North China in the eastern tropical Tethyan region, and archived important information of climate and sea-level changes. Though several high-precision zircon UPb ages have been reported, they have some conflicts with previously defined biostratigraphic correlations, especially for the Taiyuan Formation. Lack of high-resolution conodont biostratigraphy has impeded the correlation with other well-studied Pangean records. In this study, five conodont zones were established for the successions of the Taiyuan Formation in southern North China. They are Streptognathodus wabaunsensis, S. isolatus, S. sigmoidalis, S. constrictus and S. fusus biozones in ascending order, constraining a late Gzhelian to late Asselian age for the Taiyuan Formation in southern North China, which is consistent with published high-precision zircon UPb ages. The Unitary Association (UA) analysis was used to reconcile the conodont biostratigraphy of the Taiyuan Formation in North China, and was combined with previously published high-precision UPb ages to construct a new chronostratigraphic framework for the Carboniferous-Permian strata across North China. It explicitly indicates an earlier initiation of climate aridification in the northern part than in the southern part of North China possibly due to northward drift and/or increased atmospheric pCO2 and associated global warming.