Atmospheric P co ₂ Perturbations Associated with the Central Atlantic Magmatic Province

Abstract

The effects of a large igneous province on the concentration of atmospheric carbon dioxide (PCO₂) are mostly unknown. In this study, we estimate PCO₂ from stable isotopic values of pedogenic carbonates interbedded with volcanics of the Central Atlantic Magmatic Province (CAMP) in the Newark Basin, eastern North America. We find pre-CAMP PCO₂ values of ~2000 parts per million (ppm), increasing to ~4400 ppm immediately after the first volcanic unit, followed by a steady decrease toward pre-eruptive levels over the subsequent 300 thousand years, a pattern that is repeated after the second and third flow units. We interpret each PCO₂ increase as a direct response to magmatic activity (primary outgassing or contact metamorphism). The systematic decreases in PCO₂ after each magmatic episode probably reflect consumption of atmospheric CO₂ by weathering of silicates, stimulated by fresh CAMP volcanics.

Comment on “Atmospheric P co 2 Perturbations Associated with the Central Atlantic Magmatic Province”

“…1). Instantaneous release of 10 16 kg of CO 2 results in an increase of PCO 2 of about 1300 ppm over a high early Jurassic background of about 2000 ppm, similar to results of Schaller et al (1). If the release is accomplished over a substantial time period, then one must take into account uptake of CO 2 by the oceans, and if long enough, interactions with the solid earth through rock weathering.…”

Episodic photic zone euxinia in the northeastern Panthalassic Ocean during the end-Triassic extinction

“…The expansion of OMZs during hothouse conditions may be aided by density stratification due to intense evaporation over epicontinental basins and/or a reduced latitudinal thermal gradient, suppressing high-latitude deep-water formation, thermohaline circulation, and ocean ventilation (Kidder and Worsley, 2010). Massive pulses of atmospheric CO 2 (to ~4400 ppm) from phases of Central Atlantic magmatic province volcanism (Schaller et al, 2011) are now more precisely dated to the ETE (Blackburn et al, 2013), and are synchronous with marine extinctions (e.g., Whiteside et al, 2010), fossil flora suggestive of increased CO 2 and extreme warming (McElwain et al, 1999), and enhanced wildfire activity (Belcher et al, 2010). The rise in pCO 2 was also coincident with a major disruption in biocalcification (van de Schootbrugge et al, 2007), possibly caused by ocean acidification, such as during the late Permian.…”

On the reconstruction of plant photosynthetic and stress physiology across the Triassic–Jurassic boundary

“…The development of the Central Atlantic Magmatic Province (CAMP) at the boundary is widely considered to be a cause of the TJB event (e.g., Hesselbo et al, 2002;Guex et al, 2004;Marzoli et al, 2004;Kürschner et al, 2007;Ruhl et al, 2009;Van de Schootbrugge et al, 2009;Schoene et al, 2010) releasing large volumes of CO 2 (McElwain et al, 1999;Beerling and Berner, 2002;Galli et al, 2005;Huynh and Poulsen, 2005;Berner and Beerling, 2007;Cleveland et al, 2008;Van de Schootbrugge et al, 2008;Bacon et al, 2011;Schaller et al, 2011;Steinthorsdottir et al, 2011) and toxic gases such as sulfur dioxide (SO 2 ) into the atmosphere (Guex et al, 2004;Berner and Beerling, 2007;Hori et al, 2007;Van de Schootbrugge et al, 2009;Bacon et al, 2013). However, a firm mechanistic explanation for how CAMPinduced environmental changes triggered Late Triassic floral biodiversity losses is still lacking (Bonis et al, 2009).…”