Intrusion Induced Global Warming Preceding Continental Flood Basalt Volcanism

Abstract

Temporal correlations between continental flood basalt eruptions and mass extinctions are well known 1. Massive carbon degassing from volcanism of Large Igneous Provinces can cause catastrophic global climatic and biotic perturbations 1–3. However, recent more accurate dating of the Deccan Traps 4 and Columbia River Basalts 5 challenges this causal link by showing that global warming preceded the major phase of flood basalts eruptions by several hundred thousand years. Here, we argue that major eruptions of continental flood basalts may require densification of the crust by intrusion of larger volumes of magma than are extruded. Simple models show that magma crystallization and release of CO2 from such intrusions could produce global warming before the main phase of flood basalt eruptions on the observed timescale. Being consistent with many geological, geophysical, geochemical and paleoclimate data, our model suggests that the evolving crustal density has a first order control on timing of the major phase of continental flood basalt volcanism while the preceding intrusion induced underground degassing of CO2 plays a significant role in controlling the Earth's climate and habitability.