Volume and rate of volcanic CO ₂ emissions governed the severity of past environmental crises

Abstract

The emplacement of large igneous provinces (LIPs) has been linked to catastrophic mass extinctions in Earth’s history, but some LIPs are only associated with less severe oceanic anoxic events, and others have negligible environmental effects. Although it is widely accepted that massive magma outpouring can affect the environment through volatile degassing, it remains debated what controls the severity of environmental crises. Here, we demonstrate that the second-most-voluminous Phanerozoic LIP, the Kerguelen LIP, may have contributed to the early Aptian oceanic anoxic event 1a, a global event previously believed to have been caused by the Ontong Java LIP. Geochronological data show that the earliest eruptions of the Kerguelen LIP preceded the onset of oceanic anoxic event 1a by at least ∼5 million years. Analyses of CO 2 abundances in melt inclusions combined with Monte Carlo simulations reveal that the volume and degassing rate of CO 2 emissions from the Kerguelen LIP are an order of magnitude lower compared to LIPs that caused severe mass extinctions. We propose that the severity of volcanism-related environmental and biotic perturbations is positively correlated with the volume and rate of CO 2 emissions. Our results highlight the significant importance of reducing and slowing down CO 2 emission in preventing future disastrous environmental consequences.

Early Jurassic large igneous province carbon emissions constrained by sedimentary mercury

“…We compare estimated carbon emitted during the T-OAE n-CIE (KFLIP main phase) between ~183 and 182 Ma with independent total carbon and average emission rate estimates from LIP-volcanology-based proxies (for example, melt inclusions, igneous geochemistry and modelling of magmatic processes) for several other LIPs 45 (Fig. 4).…”

“…A Hg/CO 2 ratio of 5 × 10 −8 is shown to illustrate the maximum possible CO 2 emissions that may occur in specific diffusive degassing scenarios 53 , although it is unlikely to represent a long-term net composition. Other LIP carbon emissions from a literature compilation 3,45,54 : the green bars on the right of the plot represent LIP-proxy-based estimates of the quantity of total carbon emissions for several other LIPs (based on a combination of CO 2 content estimates, from melt inclusions and geochemical ratios, and thermogenic emissions estimates, and total LIP volumes), and the green dotted lines represent the average rate of carbon emission for those LIPs (based on the total quantity and the estimated emplacement duration). The Siberian Traps and CAMP represent LIPs with substantial associated thermogenic carbon emissions, and the Deccan Traps and Kerguelen Plateau represent LIPs with minimal thermogenic carbon emissions.…”