| Titre | Down-canyon evolution of turbidity currents at a late-glacial ice margin: Halibut Canyon, offshore southeastern Canada |
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| Auteur | Tang, M; Piper, D J W |
| Source | Marine Geology vol. 424, 106182, 2020 p. 1-20, https://doi.org/10.1016/j.margeo.2020.106182 |
| Image |  |
| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20190311 |
| Éditeur | Elsevier |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.margeo.2020.106182 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Région extracotière de l'est; Terre-Neuve-et-Labrador |
| SNRC | 1 |
| Région | Halibut Canyon |
| Lat/Long OENS | -55.6667 -54.6667 45.3333 44.6667 |
| Sujets | sédiments marins; courants de turbidite; caractéristiques sous-marines; canyons sous-marins; évolution géologique; antecedents de sedimentation; lithofaciès; antecedents glaciaires; déglaciation; marges
glaciaires; carottes de sédiment marin; méthodes de fluorescence aux rayons x; structures sédimentaires; datation radiométrique; datation au radiocarbone; interprétations géophysiques; interpretations sismiques; repartition granulométrique;
corrélations stratigraphiques; micropaléontologie; microfossiles; Foraminifères; effets cumulatifs; géologie marine; géologie des dépôts meubles/géomorphologie; sédimentologie; stratigraphie; géochimie; géochronologie; géophysique; Nature et
environnement; Sciences et technologie; Phanérozoïque; Cénozoïque; Quaternaire |
| Illustrations | cartes de localisation; cartes géolscientiques généralisées; diagrammes 3D; graphiques; profils sismiques; tableaux; coupes de corrélation; profils; photographies; images géophysiques; diagrammes
de distribution des fréquences; séries chronologiques; modèles; coupes schématiques transversales; représentations schématiques |
| Programme | Géosciences marines pour la planification spatiale marine |
| Diffusé | 2020 03 18 |
| Résumé | (disponible en anglais seulement)
Turbidity currents are the most voluminous sediment transport processes on the continental slope, and it is important to understand how they behave through
canyon systems. This study investigated 7 cores from Halibut Canyon, located seaward of a small ice stream draining the Newfoundland Ice Dome. Cores were X-radiographed for sedimentary structures, sediment geochemistry was assessed by X-ray
fluorescence scanning to determine provenance, and age was determined by AMS C-14 dating. High resolution seismic profiles and core records show three phases of canyon evolution: (1) canyon erosion by plunging hyperpycnal meltwater from shelf-edge
ice at maximum ice extent. (2) During deglaciation, active canyon deposition of an inner levee by turbidity currents, adjacent to an erosional talweg system. Cores record this phase from the Younger Dryas (12 ka) to before H1 (16.5 ka). (3) Passive
canyon fill during the Holocene by the alongslope Labrador Current. Evidence suggests that deposition from Laurentian Current dominated during Holocene, with only minor down-canyon sediment supply. In the active canyon deposition phase, turbidity
currents were of variable size, reaching thicknesses >390 m at 40 km down canyon. Numbers of sand beds and mean grain size decrease down canyon, which results from rapid entrainment of ambient seawater on the steep gradient and a downflow thinning of
the lower part of the current with fine sand in suspension. Silt becomes increasingly segregated from muds downcanyon as a result of floc break-up and re-formation. The processes inferred from Halibut Canyon are representative of other canyons on
formerly glaciated margins. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Description et interprétation des processus de sédimentation modernes et tardiglaciaires dans le canyon Halibut. |
| GEOSCAN ID | 315688 |
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