Marine and Terrestrial Carbon Cycle Responses to Large Igneous Province Volcanism at the Triassic–Jurassic (Tr–J) Boundary

The end–Triassic mass extinction (ETME) and global biotic disturbance resulted from marine and continental environmental perturbance linked to the onset of Central Atlantic Magmatic Province (CAMP) emplacement. Major and rapid carbon release during this time, associated changes in the global carbon cycle are recorded as successive negative carbon isotope excursions (CIEs) in sedimentary archives. This study aims, for the first time, to resolve the coupling between atmospheric pCO2 variations, carbon cycle perturbation, onset of CAMP volcanism, and associated extinction dynamics, through integration with high-resolution carbon isotope (δ13C) records from marine sedimentary archive of Carnduff–2 (CRN–2) core from the Larne Basin (Northern Ireland) and terrestrial sedimentary archive of Astartekløft (Jameson Land Basin, East Greenland). The CRN–2 is characterized by a ~5‰ negative carbon-isotope excursion (CIE) associated with the ETME, and cyclostratigraphic analysis of sedimentary elemental and magnetic susceptibility data enables high-resolution depth–time conversion, indicating a ~230 kyr duration for the negative CIE that reflects a Tr–J global carbon cycle perturbation and providing a detailed chronology and timescale across the Tr–J transition. We also present new δ13CTOC and plant (wood) and sedimentary mercury (Hg) data from the Astartekløft section, shows ~3‰ negative CIE and elevated Hg levels at the ETME event horizon. Refined chemostratigraphic (δ13CTOC) correlation between the Jameson Land (Astartekløft section) and Larne (CRN–2 core) basin provides the robust and temporally constrained linkage between atmospheric Hg loading from CAMP emplacement (inferred from plant sedimentary Hg enrichment), elevated atmospheric pCO2 (inferred from previous stomatal density analyses of fossil leaves from the same sections), and global carbon cycle disturbance and underscoring the dynamic environmental instability that during the Tr–J transition.