Carbon‐dioxide releases associated with a mid‐Cretaceous super plume and the emplacement of the Ontong‐Java Plateau have been suggested as a principal cause of the mid‐Cretaceous global warming. We developed a carbonate‐silicate cycle model to quantify the possible climatic effects of these CO2 releases, utilizing four different formulations for the rate of silicate‐rock weathering as a function of atmospheric CO2. We find that CO2 emissions resulting from super‐plume tectonics could have produced atmospheric CO2 levels from 3.7 to 14.7 times the modern pre‐industrial value of 285 ppm. Based on the temperature sensitivity to CO2 increases used in the weathering‐rate formulations, this would cause a global warming of from 2.8 to 7.7°C over today's global mean temperature. Altered continental positions and higher sea level may have been contributed about 4.8°C to mid‐Cretaceous warming. Thus, the combined effects of paleogeographic changes and super‐plume related CO2 emissions could be in the range of 7.6 to 12.5°C, within the 6 to 14°C range previously estimated for mid‐Cretaceous warming. CO2 releases from oceanic plateaus alone are unlikely to have been directly responsible for more than 20% of the mid‐Cretaceous increase in atmospheric CO2.
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)