HAL : hal-00371235, version 1

DOI : 10.1130/G25325A.1

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Geology 37, 4 (2009) 323-326

Climate changes caused by degassing of sediments during the emplacement of large igneous provinces

Clément Ganino 1, 2, Nicholas Arndt 1

(01/04/2009)

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

1 :	Laboratoire de géodynamique des chaines alpines (LGCA)
	CNRS : UMR5025 – OSUG – INSU – Université de Savoie – Université Joseph Fourier - Grenoble I
2 :	Géoazur (GEOAZUR)
	Université Nice Sophia Antipolis [UNS] – CNRS : UMR6526 – Institut de recherche pour le développement [IRD] – Observatoire de la Côte d'Azur – INSU – Université Pierre et Marie Curie [UPMC] - Paris VI

Domaine

:

Planète et Univers/Sciences de la Terre Planète et Univers/Interfaces continentales, environnement Sciences de l'environnement/Milieux et Changements globaux

Mots Clés : large igneous province – mass extinction – contact metamorphism – sedimentary wall-rock – Emeishan

hal-00371235, version 1

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Contributeur : Clément Ganino <>

Soumis le : Vendredi 27 Mars 2009, 09:23:24

Dernière modification le : Lundi 30 Mars 2009, 11:58:48