Volcanism and wildfire associated with deep-time deglaciation during the Artinskian (early Permian)  

The deep-time geological record can provide insights into the processes and mechanisms of glacier retreat. Ice sheets of the Late Paleozoic Ice Age (LPIA) collapsed extensively during the early Artinskian (early Permian) approximately 290 million years ago through massive glacial melting that was associated with dramatic increases in global temperature, atmospheric pCO2, sea level, and resulted in profound changes in terrestrial plant distribution and diversity. A hypothesized mode of this extensively glacial melting is multiple large-scale volcanic events, but the causes and effects have not yet been clearly established because of the lack of detailed coeval records of volcanism and environmental changes. Here, we present a record of these events from an Artinskian terrestrial succession in the Liujiang Coalfield, North China. Our new U–Pb zircon dating, high-resolution chemostratigraphy, and kerogen maceral data reveal that environmental changes (carbon cycle perturbation, wildfire, and continental weathering) in the region were intricately linked with the large-scale volcanism associated with the Tarim-II, Panjal and Choiyoi volcanic provinces. Our study shows that hypothesized volcanism and wildfire raised temperatures by releasing greenhouse gases, while the ensuing warming led to ice sheet melting, the release of terrestrial Hg and C and resulting Hg and C cycle anomalies.