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TitreThe High Arctic Magnetic High - The Geophysical Manifestation of a Large (1.36 x 106 km2) and Voluminous (5-10 x 106 km3) Igneous Province
AuteurSaltus, R W; Oakey, G N; Miller, E L; Jackson, R
SourceEuropean Geoscience Union annual symposium, abstracts; .
Séries alt.Secteur des sciences de la Terre, Contribution externe 20140096
ÉditeurEuropean Geiphysical Union
RéunionEuropean Geoscience Union Annual Symposium; Vienna; AT; avril 7-12, 2013
Lang.anglais
Mediapapier
ProgrammePreparation of a submission for an extended continental shelf in the Atlantic and Arctic Oceans under UNCLOS, Délimitation du plateau continental du Canada en vertu de la Convention des Nations Unies sur le droit de la mer (UNCLOS)
Résumé(disponible en anglais seulement)
The High Arctic Magnetic High (HAMH) dominates the magnetic anomaly field of the Earth north of about 75°N; this magnetic domain consists of very high amplitude magnetic highs and lows with variable orientations. The HAMH is visible on satellite magnetic compilations (e.g., MF6) with anomaly amplitudes greater than 200 nT indicating it is a globally significant feature. The magnetic potential of this magnetic feature is a single large intensity high indicative of a large volume of magnetic material in the crust. The map area of this magnetic domain is roughly 1.36 x 106 km2. Geographically the HAMH lies within the Amerasian Basin adjacent to the Lomonosov Ridge, encompasses the region of the Alpha and Mendeleev Ridges, and extends beneath the northern portions of the Canada Basin.
Ocean floor geomorphology, limited seismic and sonobouy data, sparse dredge samples, and dated samples from the perimeter of the Arctic Ocean are consistent with the interpretation of the HAMH as the geophysical manifestation of a Large Igneous Province. The designation ¿High Arctic Large Igneous Province (HALIP)¿ has been applied to portions of the Arctic perimeter based on geologic mapping and sampling. The designation ¿Alpha/Mendeleev Large Igneous Province (AMLIP)¿ has been applied to the offshore Alpha/Mendeleev region (e.g., Grantz et al., 2009) with boundaries defined, in large part, by magnetic anomaly patterns.
We have constructed 2D and 3D models of the HAMH to investigate the structure and geometry of this significant crustal feature. We estimate the overall volume of magnetic material as between 5-10 x 106 km3. The area and volume of this feature are comparable with estimates for the Deccan Traps and the North Atlantic Igneous Province, but are significantly smaller than the Kerguellen or Ontong Java Plateaus (based on tables in Coffin and Eldholm, 1994). In detail we find significant correlation between shorter wavelength portions of this magnetic feature and the comparable wavelength patterns in the complex, basin and range ¿ style bathymetry of the Alpha and Mendeleev Ridges. Although there are many open questions regarding the development of this crustal domain, the broad geophysical expression of this feature show that it represents a substantial portion of the high Arctic crust and, as a large igneous province, a significant influx of mass and heat during its formation. Any successful model for the tectonic development of the Amerasian Basin must account for the effects of these fluxes on the strength and composition of the crust.
Résumé(Résumé en langage clair et simple, non publié)
Une étude de la région du bassin amérasiatique de l'océan Arctique a examiné la configuration complexe des crêtes et des creux de grande amplitude dans le champ d'anomalie magnétique, que l'on désigne comme la crête magnétique du Haut-Arctique (HAMH pour High Arctic Magnetic High). Nous avons élaboré des modèles informatiques 2D et 3D afin d'étudier la géométrie et la composition des roches associées à la HAMH. Les résultats montrent la présence de 5 à 10 x 106 kilomètres cubes de roche volcanique dans cette région. Ces roches volcaniques forment une partie de la grande province ignée du Haut-Arctique, et ces résultats indiquent que cette province ignée est comparable en taille à d'autres grandes provinces ignées du globe. Tout modèle de mise en valeur du bassin amérasiatique doit tenir compte des effets de la masse importante et des propriétés thermiques de ces roches volcaniques sur la résistance et la composition de la croûte.
GEOSCAN ID294803