Permian carbon isotope and clay mineral records from the Xikou section, Zhen'an, Shaanxi Province, central China: Climatological implications for the easternmost Paleo-Tethys

Permian carbon isotopic and clay mineralogical records were recovered from the carbonates in the Xikou section, a complete and uninterrupted Upper Carboniferous to Lower Triassic carbonate-dominated succession exposed in Zhen'an, Shaanxi Province, central China, which were used to document carbon isotopic signatures and climatic changes affecting the easternmost Paleo-Tethys region during the Permian. Both carbon isotope and clay mineralogical data suggest fluctuating climatic conditions and trends that can be approximately correlated with eastern Australian glaciations and North American craton during the Artinskian to Capitanian Stages. Two global carbon isotopic anomalies across the Permian-Triassic boundary and the Guadalupian-Lopingian Series boundary were detected for the first time in the stratigraphic record of the South Qinling micro-continental block. The Capitanian Stage comprises an early phase of climatic warming followed by a later phase of climatic cooling. The Kungurian Stage represents a climatic warming interval and the main phase of deglaciation during the Late Paleozoic Ice Age (LPIA). A delta C-13 positive shift across the boundary of the Artinskian to Kungurian Stages, together with the following negative excursion recorded in the early Kungurian Stage can be used as an indicator for the boundary between the Artinskian and Kungurian Stage.