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TitreWater mass denitrification during the latest Permian extinction in the Sverdrup Basin, Arctic Canada
AuteurKnies, J; Grasby, S E; Beauchamp, B; Schubert, C J
SourceGeology vol. 41, no. 2, 2013 p. 167-170,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120209
ÉditeurGeological Society of America
Documentpublication en série
Mediapapier; en ligne; numérique
Lat/Long OENS-84.0000 -83.0000 79.7500 79.5000
Sujetsisotopes; rapports carbone-azote; extinctions biotiques; lithologie; Bassin de Sverdrup ; géologie marine; géochimie; Mésozoïque; Trias; Paléozoïque; Permien
Illustrationslocation maps; plots
ProgrammeBassin sédimentaire Sverdrup, GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
Late Permian - Early Triassic bulk sedimentary nitrogen isotope (d15N) and biomarker data have been generated from the northwest margin of Pangea. Sediments from the Buchanan Lake section, Arctic Canada, deposited prior to the latest Permian extinction (LPE) event are characterized by positive d15N values of ~9permil associated with the presence of lycopane, implying upwelling of denitrifi ed waters from an expanded oxygen minimum zone. The data show that anoxic bottom-water conditions were not developed in northeastern Panthalassa during the Late Permian. Promoted by dispersing coal ash from Siberian Traps volcanics, as marked by an abrupt rise in C/N ratios (>20) prior to the LPE event, euxinic conditions fi rst developed at the LPE. Pronounced differences in the nitrogen inventory across the LPE event, however, suggest that while unfavorable conditions prevailed for aerobiosis in the paleo-Tethys, persistent upwelling of deoxygenated (denitrifi ed) waters occurred in the Sverdrup Basin across the LPE, excluding the prevalence of photic zone euxinia along the northwest margin of Pangea.