Massive and rapid predominantly volcanic CO ₂ emission during the end-Permian mass extinction

Abstract

The end-Permian mass extinction event (∼252 Mya) is associated with one of the largest global carbon cycle perturbations in the Phanerozoic and is thought to be triggered by the Siberian Traps volcanism. Sizable carbon isotope excursions (CIEs) have been found at numerous sites around the world, suggesting massive quantities of 13C-depleted CO2 input into the ocean and atmosphere system. The exact magnitude and cause of the CIEs, the pace of CO2 emission, and the total quantity of CO2, however, remain poorly known. Here, we quantify the CO2 emission in an Earth system model based on new compound-specific carbon isotope records from the Finnmark Platform and an astronomically tuned age model. By quantitatively comparing the modeled surface ocean pH and boron isotope pH proxy, a massive (∼36,000 Gt C) and rapid emission (∼5 Gt C yr−1) of largely volcanic CO2 source (∼−15%) is necessary to drive the observed pattern of CIE, the abrupt decline in surface ocean pH, and the extreme global temperature increase. This suggests that the massive amount of greenhouse gases may have pushed the Earth system toward a critical tipping point, beyond which extreme changes in ocean pH and temperature led to irreversible mass extinction. The comparatively amplified CIE observed in higher plant leaf waxes suggests that the surface waters of the Finnmark Platform were likely out of equilibrium with the initial massive centennial-scale release of carbon from the massive Siberian Traps volcanism, supporting the rapidity of carbon injection. Our modeling work reveals that carbon emission pulses are accompanied by organic carbon burial, facilitated by widespread ocean anoxia.

Volcanic CO 2 degassing postdates thermogenic carbon emission during the end-Permian mass extinction

“…Degassing style change based on δ 13 C-PCO 2 "double inversion" Previous carbon cycle modeling studies on the EPME mostly adopted a forward box modeling approach (12,13,(20)(21)(22)(23)(24). The few published inverse modeling studies, in which continuously varying carbon emissions were diagnosed, were based on a carbon isotope assimilation approach, targeting δ 13 C signal of marine dissolved inorganic carbon (DIC) inferred from a single site of either marine carbonates (17) or marine algae biomarker based on short-chain n-alkanes (18). However, this approach is only capable of generating a nonunique carbon emission solution that is dependent on the assumed δ 13 C source , which is further considered to be invariant, precluding understanding of whether and how the δ 13 C source values evolve with changes in degassing styles of the volcanism.…”

“…We use these as inputs to the cGENIE Earth system model configured in a data inversion mode [e.g., (25) and see Materials and Methods for detailed model descriptions] and use δ 11 B-based pH proxy data subsequently as a test of the derived scenarios. Our chosen records of δ 13 C carb and PCO 2 have several advantages for constraining the carbon emission history during the EPME: (i) The use of a δ 13 C carb stack rather than a single δ 13 C profile of marine carbonate or algae biomarker (18) helps exclude minor fluctuations caused by local effects and/or sparse sampling in a single record; (ii) the high-resolution PCO 2 record estimated by carbon isotope fractionation of C 3 land plants from southwestern China is near continuous and has already been aligned with the δ 13 C carb forcing (9); and (iii) the near-continuous PCO 2 record has a higher temporal resolution than the available pH datasets (12,13) or phytane-based PCO 2 estimates (11,30), enabling the potential to offer previously unidentified insight into the evolving carbon emissions across the EPME.…”

“…The trigger for the event and source of the 13 C-depleted carbon, at least of the initial CO 2 release to the atmosphere, is generally ascribed to the Siberian Traps Large Igneous Province (LIP), with possible contributions from felsic volcanism along the circum-Pangea subduction zone (14)(15)(16). However, in previous studies reconstructing CO 2 emission rates, the carbon isotopic values of the carbon source (δ 13 C source ) were assumed to be constant across the event (17,18) or just two potential isotopically distinct end-member inputs were considered with a rapid switch between them (12,13). For instance, using a carbon cycle box model to match observed δ 13 C and surface ocean pH (δ 11 B) trends, Jurikova et al (13) inferred an initially slow release of 13 C-enriched mantle CO 2 (−6‰) that predated the rapid release of 13 C-depleted carbon emission (−18‰).…”

Stratigraphic and Spatial Extent of HALIP Magmatism in Central Spitsbergen

“…The large volumes of lava erupted during a LIP can release immense volumes of CO 2 (Courtillot & Renne, 2003; Cui et al., 2021). In addition, contact metamorphism in the shallow plumbing systems of LIPs emplaced in sedimentary basins can generate extensive amounts of greenhouse gases (Aarnes et al., 2010), which may be subsequently released to the atmosphere through, for instance, hydrothermal venting (Svensen et al., 2004).…”

“…In addition, contact metamorphism in the shallow plumbing systems of LIPs emplaced in sedimentary basins can generate extensive amounts of greenhouse gases (Aarnes et al., 2010), which may be subsequently released to the atmosphere through, for instance, hydrothermal venting (Svensen et al., 2004). The eruption of large igneous provinces (LIPs), and the emplacement of their subsurface plumbing systems, is often correlated with global climate change, which potentially lead to mass extinctions (Courtillot & Renne, 2003; Cui et al., 2021; Ernst & Youbi, 2017; Svensen et al., 2019).…”