Deep CO2 from the Central Atlantic Magmatic Province during the end-Triassic mass extinction

Abstract

<p>Throughout Earth’s history, the coincidence in time between Large Igneous Province eruptions and mass extinctions points out a potential causality, where volcanic degassing may drive the global-scale climatic and environmental changes leading to biotic crises. The volcanic activity of the Central Atlantic Magmatic Province (CAMP, ca. 201 Ma), one of Earth’s most voluminous Large Igneous Provinces, is synchronous with the end-Triassic mass extinction event, among the most severe extinctions during the Phanerozoic. Combining different in situ analytical techniques (optical microscopy, confocal Raman microspectroscopy, EMP, SEM-EDS, and NanoSIMS analyses), bubble-bearing melt inclusions within basaltic rocks revealed the abundance of CO<sub>2</sub> (up to 1.0 wt.%) in CAMP magmas [1]. Gaseous CO<sub>2 </sub>and solid elemental C, alternatively preserved by gas exsolution bubbles within melt inclusions mainly hosted in clinopyroxene crystal clots, represent direct evidence for large amounts of volcanic CO<sub>2</sub> (up to 10<sup>5</sup> Gt) emitted into Earth’s surface during the entire CAMP activity [1]. The entrapment conditions of these melt inclusions within clinopyroxene aggregates constrain the degassed CO<sub>2</sub> to a mantle and/or lower-middle crustal origin, indicating a deep source of carbon which may favour rapid and intense CAMP eruption pulses. Each magmatic pulse may have injected CO<sub>2</sub> into the end-Triassic atmosphere in amounts similar to those projected for the anthropogenic emissions during the 21<sup>st</sup> century [1]. Therefore, volcanic CO<sub>2</sub> degassed during CAMP eruptions likely contributed to end-Triassic global warming and ocean acidification with catastrophic consequences for the biosphere.</p><p> </p><p>[1] Capriolo et al. (2020), Nat. Commun. <strong>11</strong>, 1670.</p>