During the Ordovician, huge biological revolutions and environmental changes happened in Earth’s history, including the Great Ordovician Biodiversification Event, global cooling and so on, but the cause of these events remains controversial. Herein, we conducted a paired carbon iso-topic analysis of carbonate (d13Ccarb) and organic matter (d13Corg) through the Ordovician in the Qiliao section on the Yangtze platform of South China. Our results showed that the d13Ccarb trend of the Qiliao section can be correlated with local and global curves. The d13Corg trend seems is less clear than the d13Ccarb trend for stratigraphic correlations, but some d13Corg positive excursion sin the Middle and Upper Ordovician may be used for correlation studies. These carbon isotopic records may have global significance rather than local significance, revealing several fluctuations to the global carbon cycle during the Ordovician. Several known d13Ccarb and d13Corg negative and positive excursions have been recognised in this study, including the early Floian Negative Inorganic Carbon (d13Ccarb) Excursion (EFNICE), as well as the early Floian Positive Organic Carbon(d13Ccarb) Excursion, the mid-Darriwilian Inorganic Carbon (d13Ccarb and d13Corg) Excursion (MDICE),and the early Katian Guttenberg Inorganic Carbon (d13Ccarb and d13Corg) Excursion (GICE). These positive excursions and a smooth decline trend of d13Corg values during the early to mid-Floian may imply multiple episodes of enhanced organic carbon burial that began at the early Floian stage, probably resulting in further decline in atmospheric pCO2 and then global cooling.
carbon isotope stratigraphy; Ordovician; positive excursion; global cooling; Yangtze platform