CARBON INJECTION DURING THE END-PERMIAN MASS EXTINCTION: MODEL INVERSION OF CARBON ISOTOPE EXCURSION

Numerous lines of geochemical and stable isotopic evidence indicate that the most devastating mass extinction that occurred at the end of Permian is tied to drastic climate change induced by CO₂ addition. Catastrophic end-Permian Siberian volcanism may have released large amount of CO₂ into the atmosphere and pushed the Earth’s system beyond a critical threshold causing the mass extinction. However, the injection rate, total amount and source of CO₂ is largely unknown. We conducted a suite of simulations using carbon isotope records from the Gartnerkofel-1 core in Carnic Alps, Austria, and section D in Meishan Zhejiang province, China. An Earth System Model of Intermediate Complexity (EMIC) (Genie-1; http://www.genie.ac.uk) was used to extract the pattern of CO₂ release needed to replicate the observed carbon isotope excursion across the P-T boundary. We also assessed the ocean saturation profile, surface water pHs and the ocean buffering capacity in response to the predicted greenhouse gas addition. As with the Paleocene-Eocene boundary event, end-Permian rates of CO₂ addition are small compared with fossil-fuel burning but protracted. In addition, the lack of pelagic carbonate production and thus a seafloor carbonate buffer made the Earth system much more sensitive to CO₂ addition.