Crustal structure and evolution of the southern Vøring Basin and Vøring Transform Margin, NE Atlantic |
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| Authors: | T Raum R Mjelde H Shimamura Y Murai E Brstein RM Karpuz K Kravik HJ Kolst |
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| Institution: | aDepartment of Earth Science (IFG), Allégt. 41, University of Bergen, 5007 Bergen, Norway;bIFG, University of Bergen, Norway;cInstitute of Seismology and Volcanology (ISV), Hokkaido University, Sapporo 060, Japan;dISV, Hokkaido University, Japan;eNorwegian Petroleum Directorate, Stavanger, Norway;fNorsk Hydro Reseach Centre, Bergen, Norway;gTotal, Stavanger, Norway;hTotal, Stavanger, Norway |
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| Abstract: | The dominantly passive volcanic Vøring and Møre Margins, NE Atlantic, are separated by the 200 km long Vøring Transform Margin (VTM). The southern Vøring Basin and the VTM have been studied by use of four regional Ocean Bottom Seismograph (OBS) profiles, combined by gravity modelling. The models demonstrate a complex pattern of magmatism along the transform margin. The distribution of magmatism seems to be related to the existence and trend of a lower crustal 8+ km/s body, interpreted as eclogitized rocks, present in the southern Vøring Basin. Early Tertiary breakup related magmatic ‘leakage’ across the Continent–Ocean-Transition (COT) appears to be facilitated where this layer is absent. These results support earlier workers who have concluded that the Jan Mayen Fracture Zone originated from a Caledonian zone of weakness. We propose that partly eclogitized rocks were uplifted into the lower crust close to this zone during the Caledonian orogeny and that this body acted as a barrier to magma emplacement during the Late Cretaceous–Early Eocene phase of rifting/breakup. The eclogitized terrain also appears to have caused northeastward channeling of the Late Cretaceous–Early Tertiary intrusions within the Vøring Basin. An up to 10 km thick pre-Cretaceous sedimentary basin in the southern Vøring Basin may be genetically related to the NS-trending Late Paleozoic and Mesozoic rift basins in North-East Greenland. |
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| Keywords: | Wide-angle refraction Eclogitized rocks COT |
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