[B-CG06] Decoding the history of Earth: From Hadean to the present

[BCG06-16] Role of volcanism and impact heating in mass extinction climate shifts

*Kunio Kaiho¹ (1.Tohoku University)

Keywords:large volcanism, bolide impact, heating temperature, stratospheric aerosols, climate change, mass extinction

This study delves into the mechanisms behind the diverse climate changes observed during mass extinctions in the Phanerozoic era, marked by both global cooling and global warming effects, yet with unclear causes for these variations. We emphasize the significance of sedimentary rock temperature in comprehending these climate shifts. Our research reveals that low-temperature heating of sulfide leads to global cooling through the release of sulfur dioxide (SO₂), while intermediate-temperature heating of hydrocarbons and carbonates releases substantial carbon dioxide (CO₂), contributing to global warming. High-temperature heating additionally generates SO₂ from sulfate, further contributing to global cooling. Different degrees of contact heating of the host rock can lead to different dominant volatile gas emissions, crucially driving either warming or cooling. Moreover, medium to high-temperature shock-heating resulting from asteroid impacts produces soot from hydrocarbons, also contributing to global cooling. Large-scale volcanic activity and asteroid impacts are both events that heat rocks, emitting the same gases and particles, causing climate changes. The findings elucidate the critical role of heating temperature and heating time in understanding major climate changes during mass extinctions.