Quantifying volcanism and organic carbon burial across Oceanic Anoxic Event 2

Oceanic Anoxic Event 2 (ca. 94 Ma; OAE2) was one of the largest Mesozoic carbon cycle perturbations, but associated carbon emissions, primarily from the Caribbean large igneous province (LIP) and marine burial fluxes, are poorly constrained. Here, we use the carbon cycle box model LOSCAR-P to quantify the role of LIP volcanism and enhanced marine organic carbon (C-org) burial as constrained by the magnitude and shape of the positive stable carbon isotope (delta C-13) excursion (CIE) in the exogenic carbon pool and atmospheric pCO 2 reconstructions. In our best fit scenario, two pulses of volcanic carbon input-0.065 Pg C yr(-1) over 170 k.y. and 0.075 Pg C yr(-1) over 40 k.y., separated by an 80 k.y. interval with an input of 0.02 Pg C yr l-are required to simulate observed changes in delta C-13 and pCO(2). Reduced LIP activity and C ore burial lead to pronounced pCO(2) reductions at the termination of both volcanic pulses, consistent with widespread evidence for cooling and a temporal negative trend in the global exogenic delta C-13 record. Finally, we show that observed leads and lags between such features in the records and simulations are explained by differences in the response time of components of the carbon cycle to volcanic forcing.

Automated summary

In this study, the carbon cycle box model LOSCAR-P is used to quantify the impact of Caribbean large igneous province (LIP) volcanism and enhanced marine organic carbon burial on the carbon cycle perturbation during the Oceanic Anoxic Event 2 (OAE2). The results show that two pulses of volcanic carbon input are required to simulate the observed changes in delta C-13 and pCO2, and reduced LIP activity and carbon burial lead to pronounced pCO2 reductions.