| Titre | Contrasting styles of magmatism and rifting in the High Arctic LIP, Sverdrup Basin, Canadian Arctic |
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| Auteur | Williamson, M -C ;
Shephard, G E; Kellett, D A |
| Source | EGU Assembly 2021; Geophysical Research Abstracts 2021 p. 1, https://doi.org/10.5194/egusphere-egu21-12230 |
| Image |  |
| Année | 2021 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200686 |
| Éditeur | Copernicus |
| Réunion | European Geophysical Union Assembly 2021; avril 19-30, 2021 |
| Document | site Web |
| Lang. | anglais |
| DOI | https://doi.org/10.5194/egusphere-egu21-12230 |
| Media | en ligne; numérique |
| Formats | html; pdf |
| Province | Nunavut; Région extracotière du nord |
| SNRC | 49G; 59E; 59F; 59G; 59H; 120F; 340B; 340C; 340D; 340E; 340F; 560A; 560D |
| Région | Axel Heiberg Island; île d'Ellesmere; Océan Arctique |
| Lat/Long OENS | -96.0000 -64.0000 83.5000 78.0000 |
| Sujets | antécédents tectoniques; magmatisme; intrusions; volcanisme; mise en place; décrochement horizontal; expansion océanique; marges continentales; bassins sédimentaires; modèles; logiciel; fluage;
lithosphère; épaisseur de la croûte; manteau terrestre; Bassin de Sverdrup ; Bassin d'Amerasia ; Bassin de Canada ; Bassin de Makarov ; tectonique; géochronologie; géochimie; Nature et environnement; Sciences et technologie; Phanérozoïque;
Mésozoïque; Crétacé; Paléozoïque; Permien; Carbonifère |
| Programme | Division de la CGC du Centre du Canada |
| Diffusé | 2021 03 04 |
| Résumé | (disponible en anglais seulement)
Located along the Canadian polar continental margin, the Sverdrup Basin is an elongated, intracontinental sedimentary basin that originated during
Carboniferous-Early Permian rifting. Starting in the Early Cretaceous, volcanic complexes (VC) were emplaced throughout the basin, which are associated with the High Arctic Large Igneous Province (HALIP). Geochronological and geochemical data on
HALIP rocks exposed on Axel Heiberg Island and northern Ellesmere Island suggest several discrete stages of emplacement; (1) voluminous mafic intrusive activity of tholeiitic character accompanied by minor extrusive volcanism at ca. 125-110 Ma
(VC1a); the eruption of tholeiitic flood basalts on Axel Heiberg Island at ca. 100-90 Ma (VC1b); the emplacement of mildly alkaline lava flows, sills and dykes on Ellesmere Island at ca. 100-90 Ma (VC2); and the eruption of a suite of alkaline lava
flows from central volcanoes at ca. 85-75 Ma (VC3). Each magmatic episode is characterized by a distinctive eruptive style and coherent geochemical signature regardless of the mode of emplacement. In this context, onshore manifestations of the HALIP
can be viewed as time-markers in the evolution of the adjacent polar continental margin.
We use digital plate tectonic models, constructed via the GPlates software, to explore the parallel development of the Sverdrup Basin and proto-Arctic Ocean
(Amerasia Basin) during the Early Cretaceous, and the transition from a sedimentary to volcanic Sverdrup Basin. Plate reconstructions of the Amerasia Basin at ca. 125 Ma suggest two zones of extension; one within the Canada Basin, which may include
seafloor spreading, (Zone 1, more distal to the Sverdrup Basin) and the second further northwards in the Alpha-Mendeleev Ridge and Makarov Basin domains offshore northern Ellesmere Island (Zone 2, proximal to the northeastern portion of the Sverdrup
Basin). The potential for enhanced melting caused by mantle flow (possibly related to the arrival of a mantle plume) towards the Sverdrup Basin depocentre could explain widespread magmatism of tholeiitic character from ca. 125-90 Ma (VC1). The
transition to mildly alkaline (VC2) and alkaline magmatism (VC3) at ca. 100 Ma may have signaled the end of extension in Zone 1. The persistence of localized extension in Zone 2 could explain the shift in magmatic style and compositional diversity of
igneous rocks emplaced at intrusive complexes (VC2) vs constructional volcanic edifices (VC3). In addition, greater depth to Moho along the northeastern Sverdrup Basin may have contributed to restricted mantle flow in Zone 2. We propose that the
spatio-temporal evolution of HALIP magmatism in the Sverdrup Basin during the Cretaceous relates to (1) different styles of tectonic extension (distal vs proximal, protracted vs discrete, widespread vs narrow, seafloor spreading vs hyper-extensional
rifting), and (2) the presence of hot, thin lithosphere close to the basin depocentre vs cold and thick lithosphere in the northeastern part of the basin. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Dans cette présentation, nous utilisons des modèles numériques de la tectonique des plaques, construits à partir du logiciel GPlates, pour
explorer le développement parallèle du bassin de Sverdrup et de l'océan Arctique (bassin d'Amerasia) au cours du Crétacé. Une comparaison du régime d'extension dans les deux régions d'étude avec l'âge de chaque épisode magmatique de la Grande
Province Ignée de l'Extrême-Arctique (HALIP) suggère deux styles d'extension tectonique distincts dans le bassin de Sverdrup. Les résultats de cette étude améliorent notre compréhension du cadre tectonique de l'océan Arctique, de la marge
continentale polaire et du bassin de Sverdrup au cours du Crétacé. |
| GEOSCAN ID | 327974 |
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