Methane Release from Igneous Intrusion of Coal during Late Permian Extinction Events

Unusually large and locally variable carbon isotope excursions coincident with mass extinctions at the end of the Permian Period (253 Ma) and Guadalupian Epoch (260 Ma) can be attributed to methane outbursts to the atmosphere. Methane has isotopic values (δ13C) low enough to reduce to feasible amounts the carbon required for isotopic mass balance. The duration of the carbon isotopic excursions and inferred methane releases are here constrained to