Characteristics and evolution of inertinite abundance and atmospheric pO2 during China’s coal-forming periods

Abstract Coal, especially the inertinite in it, is highly sensitive to climate changes, showing an obvious response to paleoclimate conditions, in particular, to paleo-oxygen concentration (pO2). In this study, the inertinite abundance data of typical coal-forming periods in China were systematically collected and analyzed. Its characteristics and control factors were studied, and its evolution was established. Based on inertinite abundance data, pO2 evolution curves of various coal-forming periods in China were established, which fluctuated between 15% and 30% during the entire Phanerozoic. The inertinite abundance in coal deposits during Paleozoic in China was basically consistent with that of other areas of the world, while it was quite different globally from the Mesozoic to the Cenozoic. The results show that the inertinite abundance in coal deposits is controlled by pO2 and other factors including climatic zones, plant differentiation, sedimentary environments, and tectonic activities. The inertinite abundance in coal deposits in China during the Jurassic was high, suggesting dry paleoclimate of inland China.