Carbon cycle perturbation and stabilization in the wake of the Triassic‐Jurassic boundary mass‐extinction event

Abstract

[1] The Triassic-Jurassic boundary mass-extinction event (T-J; 199.6 Ma) is associated with major perturbations in the carbon cycle recorded in stable carbon isotopes. Two rapid negative isotope excursions in bulk organic carbon (d 13 C org ) occur within the immediate boundary interval at multiple locations and have been linked to the outgassing of 12 C-enriched CO 2 from the Central Atlantic Magmatic Province. In British Columbia, a positive d 13 C org excursion of +5% (Vienna Peedee belemnite (V-PDB)) spans part or all of the subsequent Hettangian stage. Here, we examine the significance of these carbon isotope excursions as records of global carbon cycle dynamics across the T-J boundary and test the link between carbon cycle perturbation-stabilization and biotic extinction-recovery patterns. A combination of d 13 C org and palynological analyses from the Late Triassic to Early Jurassic in the Mingolsheim core (Germany) suggests that organic carbon isotope variations are best explained as the result of both compositional changes in terrestrial versus marine input and disturbance and recovery patterns of major terrestrial plant groups across the T-J boundary. A new high-resolution d 13 C carb record from the Val Adrara section in the Southern Alps (Italy) spanning from the uppermost Rhaetian through Lower Sinemurian does not exhibit a negative excursion at the T-J boundary but does record a large positive d 13 C carb excursion of +4% (V-PDB) in bulk carbonate that begins at the T-J boundary and reaches a local maximum at the Early Late Hettangian boundary. Values then gradually decrease reaching +0.5% at the Hettangian-Sinemurian boundary and remain relatively constant into the Early Sinemurian. Complementary d 13 C carb data from 4 more sections that span the Hettangian-Sinemurian boundary support carbon cycle stabilization within the Upper Hettangian. Our analyses suggest that isotope changes in organic carbon reservoirs do not necessarily require a shift in the global exogenic carbon reservoir and that the positive excursion in the carbonate carbon isotope record is best explained as the combined result of an increase in atmospheric pCO 2 leading to accelerated carbon cycling, decreased skeletal carbonate production, and increased organic carbon burial lasting several hundred thousand years. The termination of the positive inorganic carbon isotope excursion coincides with the recovery of marine skeletal carbonate producers and coeval changes in terrestrial vegetation and reflects the gradual reduction in pCO 2 and the stabilization of the global carbon cycle during the Sinemurian.

Climatic disaster at the Triassic-Jurassic boundary - a clay minerals and major elements record from the Polish Basin

“…The Tri as sic-Ju ras sic bound ary (TJB) is char ac ter ized by pro nounced neg a tive ex cur sions in ma rine and ter res trial car bon iso tope re cords (e.g., Pálfy et al, 2001;Hesselbo et al, 2002;Guex et al, 2004;Ward et al, 2004;Galli et al, 2005;Williford et al, 2007;Ruhl et al, 2009;Deenen et al, 2010;White side et al, 2010;Pieñkowski et al, 2012) as well as per tur ba tions to other iso to pic sys tems (Co hen andCoe, 2002, 2007;Kuroda et al, 2010;Callegaro et al, 2012;Pieñkowski et al, 2012) . A ma jor Late Rhaetian "ini tial" neg a tive C iso tope ex cur sion (ini tial CIE) is usu ally sep a rated from a sub se quent long-term Hettangian "main" neg a tive C isotope ex cur sion (main CIE) by a dis tinct pos i tive shift in d 13 C values (Hesselbo et al, 2002(Hesselbo et al, , 2007Schootbrugge et al, 2008;Korte et al, 2009;Pieñkowski et al, 2012;Fig. 1).…”

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).…”

A new correlation of Triassic–Jurassic boundary successions in NW Europe, Nevada and Peru, and the Central Atlantic Magmatic Province: A time-line for the end-Triassic mass extinction

“…The Triassic-Jurassic boundary (TJB, 201.36 Ma;Wotzlaw et al, 2014) is associated with one of the most severe biotic crises during the Phanerozoic, the end-Triassic mass extinction (Raup and Sepkoski, 1982;Stanley, 2007), which caused floral and faunal turnovers on land (McElwain et al, 1999(McElwain et al, , 2007Olsen et al, 2002;Whiteside et al, 2007;van de Schootbrugge et al, 2009), and major extinctions in the marine realm (Hallam and Wignall, 1999;Hautmann, 2004;van de Schootbrugge et al, 2007). Based on the ecological severity, the event was ranked the third most severe crisis of the Phanerozoic (McGhee et al, 2004(McGhee et al, , 2013.…”