Large Igneous Provinces and Biotic Extinctions

The radiometrically determined ages of large igneous provinces (LIPs) show a good correlation with the ages of mass extinction events and ocean anoxic events. Several lines of evidence suggest that gases such as carbon dioxide (CO2), methane (CH4), and sulfur dioxide (SO2) released by LIP volcanism and related intrusions may be capable of causing significant environmental effects that could lead to extinctions. Factors that contribute to the environmental impact of LIP volcanism include: (1) rapid global warming and ocean acidification resulting from greenhouse gas emission, especially from related magma intrusions into carbon-bearing sedimentary rocks; this factor has led at times to oceanic anoxia events, (2) ocean surface acidification from CO2 and SO2 release, possibly leading to biocalcification crises, (3) cooling resulting from conversion of SO2 to sulfuric acid aerosols in the troposphere and lower stratosphere, and (4) acid rain from SO2, hydrochloric acid (HCl), and hydrofluoric acid (HF) emissions.