| Titre | Compositional changes in deglacial red mud event beds off the Laurentian Channel reveal source mixing, grain-size partitioning and ice retreat |
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| Auteur | Leng, W; von Dobeneck, T; Just, J; Govin, A; St-Onge, G; Piper, D J W |
| Source | Quaternary Science Reviews vol. 215, 2019 p. 98-115, https://doi.org/10.1016/j.quascirev.2019.04.031  Accès ouvert |
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| Année | 2019 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20180365 |
| Éditeur | Elsevier BV |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.quascirev.2019.04.031 |
| Media | papier; en ligne; numérique |
| Formats | pdf (Adobe® Reader®) |
| Province | Terre-Neuve-et-Labrador; Nouvelle-Écosse; Nouveau-Brunswick; Île-du-Prince-Édouard; Québec; Région extracotière de l'est |
| SNRC | 1; 2; 10; 11; 12; 20; 21; 22 |
| Région | Laurentian Channel; Laurentian Fan; Grand Banks of Newfoundland; Golfe du Saint-Laurent; Détroit de Cabot; Océan Atlantique |
| Lat/Long OENS | -72.0000 -52.0000 52.0000 43.0000 |
| Sujets | marges continentales; plate-forme continentale; talus continental; antecedents glaciaires; nappes glaciaires; déglaciation; retrait de la glace; antecedents de sedimentation; sédiments marins; boues;
débris; couches rouges; moraines; lithologie des galets; origine; régions émettrices; repartition granulométrique; géochimie des éléments majeurs; propriétés magnétiques; magnetite; hématite; transport des sediments; dispersion des sédiments; profils
de dispersion; dispersion géochimique; distribution des éléments; distribution minérale; modèles; échantillons carrotés; géologie du substratum rocheux; lithologie; analyses stratigraphiques; corrélations stratigraphiques; Calotte glaciaire
Laurentide; Bouclier Canadien; Province Appalachienne; sédiments glaciomarins; géologie marine; géologie des dépôts meubles/géomorphologie; géochimie; minéralogie; stratigraphie; Phanérozoïque; Cénozoïque; Quaternaire |
| Illustrations | cartes géolscientiques généralisées; graphique à barres; graphiques; profils; images géophysiques; diagrammes de distribution des fréquences; tableaux; diagrammes 3D; diagrammes ternaires;
modèles |
| Programme | Géoscience pour la sécurité publique Géo-risques marins |
| Diffusé | 2019 05 23 |
| Résumé | (disponible en anglais seulement)
Between 22 and 17 cal ka BP, five large meltwater events from within the Laurentian Channel Ice Stream deposited mud beds meters thick across a large area of
the Laurentian Fan and adjacent continental slopes. This study determines the sources of these event beds and relates them to the glaciological evolution of the retreating Laurentian Ice Stream. We analyzed major element and magnetic mineral contents
of these event beds and compare them with a new collection of 80 source reference samples from the Gulf of St. Lawrence area. Element ratios suggest a steady compositional change from older to younger outburst event beds, while element-specific
offsets from reference sample compositions indicate grain-size and mineral/element partitioning during suspension transport. Their magnetic properties place event beds on the source mixing trend of four reference samples groups, which represent two
magnetite-rich sources (Canadian Shield and/or Southern Newfoundland) and two hematite-rich sources (Appalachian red beds). Using a deterministic linear source mixing model based on IRM100mT, HIRM and Ca%, we find that the earlier two outburst events
had higher contributions from granitic and calcareous sources than the later three events. Combining materials, timing and scenarios of the outburst events with ice-sheet retreat and ice-stream dynamics, we argue that the subglacial sediment
depocenter of the earlier two event beds was located in the lower Laurentian Channel while that of the later three events was upstream from Cabot Strait. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Cette étude identifie les sources changeantes de dépôts de boue très épais dans les eaux profondes au large de la Nouvelle-Écosse. Le dépôt
rapide de ces lits les rend particulièrement vulnérables aux glissements de terrain sous-marins. |
| GEOSCAN ID | 313532 |
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