Climate changes caused by degassing of sediments during the emplacement of large igneous provinces
نویسندگان
چکیده
11 Most mass extinctions during the last 500 m.y. coincide with eruptions of large igneous 12 provinces (LIP): the Cretaceous-Tertiary extinction was synchronous with the Deccan 13 flood volcanism, Permian-Triassic extinction with the eruption of the enormous 14 Siberian Traps, and End-Guadalupian extinction with the Emeishan volcanic province. 15 The causal link remains disputed, however, and many LIPs apparently had no 16 significant impact on the biosphere. Here we show that a key control on the destructive 17 consequences of LIP emplacement is the type of sedimentary rock in basins beneath the 18 flood basalts. Contact metamorphism around intrusions in dolomite, evaporite, coal or 19 organic-rich shale generates large quantities of greenhouse and toxic gases (CO2, CH4, 20 SO2) which subsequently vent to the atmosphere and cause global warming and mass 21 extinctions. The release of sediment-derived gases had a far greater impact on the 22 environment than the emission of magmatic gases. 23
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