[B-CG06] 地球史解読：冥王代から現代まで

[BCG06-16] 火山活動・小天体衝突による堆積岩加熱の温度が大量絶滅時の寒冷化/温暖化を決める

*海保 邦夫¹ (1.東北大学)

キーワード：大規模火山活動、小天体衝突、加熱温度、成層圏エアロゾル、気候変動、大量絶滅

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.