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TitreLower Triassic river-dominated deltaic successions from the Sverdrup Basin, Canadian Arctic
AuteurMidwinter, D; Hadlari, T; Dewing, K
SourcePalaeogeography, Palaeoclimatology, Palaeoecology vol 476, (2017), 2017 p. 55-67, https://doi.org/10.1016/j.palaeo.2017.03.017
Année2017
Séries alt.Secteur des sciences de la Terre, Contribution externe 20160435
ÉditeurElsevier
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1016/j.palaeo.2017.03.017
Mediapapier; en ligne; numérique
Formatspdf
ProvinceTerritoires du Nord-Ouest; Nunavut
SNRC120; 28; 29; 340; 38; 39; 48; 49; 540; 58; 59; 68; 69; 78; 79; 88; 89; 98; 99
Lat/Long OENS-128.0000 -64.0000 84.0000 72.0000
Sujetsdeltas; dépôt deltaïque; chenaux anastomosés; bassins; milieu sédimentaire; végétation; grès; débit de sedimentation; sédimentologie; stratigraphie
Illustrationslocation maps; stratigraphic columns; tables; photographs; photomicrographs; ternary diagrams
ProgrammeBassin de Sverdrup de l'ouest de l'Arctique, GEM2 : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
Sedimentary facies analysis of Lower Triassic deltaic deposits tests a hypothesis that the Latest Permian Mass Extinction influenced sedimentation in the Sverdrup Basin. The pre-existing stratigraphic framework sub-divides the coeval Blind Fiord and Bjorne formations into three T-R sequences and component braid-deltaic successions, with the Latest Permian Mass Extinction at the base of the first. As described here, river-dominated deltaic facies of the first sequence are indicative of high-magnitude flood flows resulting in a predominance of upper flow regime sedimentary structures. River-dominated deltaic facies of the second sequence contain fewer upper flow regime structures recording lower energy flows that generated mostly 3D and 2D dunes. The third sequence marks the furthest progradation of the braid-delta into the basin.

Beyond the gross braided stream characteristics of the three river-dominated deltaic successions, the lower two provide a compelling comparison of depositional environments because they formed in the same basin within only a few millions years and thereby were probably subject to similar boundary conditions. We propose that the lower, Induan, sequence is dominated by upper-flow regime plane beds due to the effect of the Latest Permian Mass Extinction on vegetative cover, whereas the middle sequence is dominated by dune-scale cross-stratification formed by lower magnitude, less flood-type flows during the Olenekian.
Résumé(Résumé en langage clair et simple, non publié)
Nous avons étudié les dépôts de delta qui s'étaient formés peu de temps après l'une des plus grandes extinctions de masse de la Terre à la limite Permo-Triasique. Nous avons constaté que la signature sédimentaire ressemblait beaucoup aux paysages avant l'évolution des plantes terrestres et a conclu que l'extinction massive affectait probablement la vegetation.
GEOSCAN ID299875