| Titre | Seismic imaging of Alpha Ridge and the magmatic overprinting of the adjacent Lomonosov Ridge and Marvin Spur |
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| Auteur | Funck, T; Shimeld, J |
| Source | Online Program for the 2019 Chapman Conference on Large-scale Volcanism in the Arctic: The Role of the Mantle and Tectonics; 2019 p. 1  Accès ouvert |
| Liens | Online - En ligne
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| Image |  |
| Année | 2019 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20190264 |
| Éditeur | American Geophysical Union |
| Réunion | Chapman Conference on Large-scale Volcanism in the Arctic: The Role of the Mantle and Tectonics; Selfoss; IS; Octobre 13-18, 2019 |
| Document | site Web |
| Lang. | anglais |
| Media | en ligne; numérique |
| Formats | html; pdf |
| Province | Nunavut; Région extracotière du nord |
| Région | Océan Arctique |
| Sujets | levés géophysiques; levés sismiques marins; antécédents tectoniques; magmatisme; intrusions; modèles; tectonique; géologie marine; géophysique; Sciences et technologie; Nature et environnement |
| Programme | Délimitation du plateau continental du Canada en vertu de la Convention des Nations Unies sur le droit de la mer (UNCLOS) |
| Diffusé | 2019 10 01 |
| Résumé | (disponible en anglais seulement)
In 2016, coincident seismic reflection and refraction data were acquired over the northern flank of Alpha Ridge and the adjacent areas of Lomonosov Ridge. The
experiment was part of the Canada-Sweden Polar Expedition which employed the Canadian icebreaker Louis S. St-Laurent and the Swedish icebreaker Oden. Wide-angle reflections and refractions were recorded using sonobuoys and on-ice seismometer
stations. A 100-m-long hydrophone streamer was utilized to record the coincident seismic reflection data. The source array consisted of up to four G-guns with a maximum volume of 2000 in3. Results will be presented from two transects across the
Lomonosov Ridge, one of which continues onto the Alpha Ridge, and a third transect along the Marvin Spur. Velocity models for the crust were developed by forward modelling of travel times, supplemented by gravity modelling to provide better control
on deeper structures, in particular the Moho depth. In addition, the coincident seismic reflection data were used to extract information on the geometry of layer boundaries in the upper part of the models.
The models for the northern flank of
Alpha Ridge show up to 2 km of sediments overlying a three-layer crust consisting of: a 2-km-thick top layer with velocities between 4.4 and 4.8 km/s; a 3-km-thick layer of 5.6 km/s; and, a lower crustal layer of 6.8 km/s. The Moho depth is
determined by gravity modelling and lies around 17 km but deepens to 22 km beneath the Fedotov Seamount. The velocity structure is similar to other models from the Alpha Ridge and Mendeleev Rise, indicating that the High-Arctic Large Igneous Province
(HALIP) volcanism has created a highly homogeneous crust. The crust on Marvin Spur at the Amerasian flank of Lomonosov Ridge differs from igneous crust on Alpha Ridge. Lower crustal velocities are 6.3 km/s and are consistent with interpretations that
the spur is a continental sliver. However, like Alpha Ridge, the Marvin Spur is overlain by volcanics, and a high-amplitude wide-angle reflection multiple is modelled as a 6-km-thick high-velocity lower crust, indicating significant HALIP-related
magmatic overprinting of the spur. This overprint extends to the southern flank of Lomonosov Ridge where there is a volcanic edifice and also a 60-km-wide zone of elevated lower crustal velocities interpreted as magmatic intrusion. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Dans le cadre de l'expédition polaire Canada-Suède de 2016, des données de réflexion et de réfraction sismiques ont été recueillies sur le flanc
nord des dorsales Alpha et Lomonosov, qui figurent parmi les principales caractéristiques du bassin de l'océan Arctique. Les nouvelles données fournissent des informations précieuses sur la vitesse acoustique et, en définitive, sur la nature
géologique des roches constituant les crêtes. Cela contribue énormément à la compréhension de la formation des dorsales et de leurs relations avec la création du bassin de l'océan Arctique |
| GEOSCAN ID | 314892 |
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