| Titre | Lower Triassic river-dominated deltaic successions from the Sverdrup Basin, Canadian Arctic |
| Auteur | Midwinter, D; Hadlari, T; Dewing, K |
| Source | Palaeogeography, Palaeoclimatology, Palaeoecology vol 476, (2017), 2017 p. 55-67, https://doi.org/10.1016/j.palaeo.2017.03.017 |
| Année | 2017 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20160435 |
| Éditeur | Elsevier |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.palaeo.2017.03.017 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Territoires du Nord-Ouest; Nunavut |
| SNRC | 120; 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 |
| Sujets | deltas; dépôt deltaïque; chenaux anastomosés; bassins; milieu sédimentaire; végétation; grès; débit de sedimentation; sédimentologie; stratigraphie |
| Illustrations | location maps; stratigraphic columns; tables; photographs; photomicrographs; ternary diagrams |
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| Programme | Bassin 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 ID | 299875 |
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