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TitleContrasting styles of magmatism and rifting in the High Arctic LIP, Sverdrup Basin, Canadian Arctic
 
AuthorWilliamson, M -CORCID logo; Shephard, G E; Kellett, D AORCID logo
SourceEGU Assembly 2021; Geophysical Research Abstracts 2021 p. 1, https://doi.org/10.5194/egusphere-egu21-12230 Open Access logo Open Access
Image
Year2021
Alt SeriesNatural Resources Canada, Contribution Series 20200686
PublisherCopernicus
MeetingEuropean Geophysical Union Assembly 2021; April 19-30, 2021
DocumentWeb site
Lang.English
Mediaon-line; digital
File formathtml; pdf
ProvinceNunavut; Northern offshore region
NTS49G; 59E; 59F; 59G; 59H; 120F; 340B; 340C; 340D; 340E; 340F; 560A; 560D
AreaAxel Heiberg Island; Ellesmere Island; Arctic Ocean
Lat/Long WENS -96.0000 -64.0000 83.5000 78.0000
Subjectstectonics; geochronology; geochemistry; Nature and Environment; Science and Technology; tectonic history; magmatism; intrusions; volcanism; emplacement; rifting; sea floor spreading; continental margins; sedimentary basins; models; software; fluid flow; lithosphere; crustal thickness; mantle; High Arctic Large Igneous Province (HALIP); Sverdrup Basin; Proto-Arctic Ocean; Amerasia Basin; Canada Basin; Alpha-Mendeleev Ridge; Makarov Basin; Phanerozoic; Mesozoic; Cretaceous; Paleozoic; Permian; Carboniferous
ProgramGSC Central Canada Division
Released2021 03 04
AbstractLocated 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.
Summary(Plain Language Summary, not published)
In this presentation, we use digital plate tectonic models, constructed via the GPlates software, to explore the parallel development of the Sverdrup Basin and Arctic Ocean (Amerasia Basin) during the Cretaceous. A comparison of the extensional regime in the two study areas with the ages of each magmatic episode in the High Arctic Large Igneous Province (HALIP) suggests two different styles of tectonic extension within the Sverdrup Basin. The results of this study improve our understanding of the tectonic setting of the Arctic Ocean, the polar continental margin, and the Sverdrup Basin during the Cretaceous period.
GEOSCAN ID327974

 
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