Continent-ocean-transitions: Review, and a new tectono-magmatic model of the Vøring Plateau, NE Atlantic

A tectono-magmatic model across the Vøring Plateau, NE Atlantic, has been derived from a densely sampled ocean bottom seismic profile, constrained by multichannel seismic and gravity data. The last phase of rifting, breakup at ca. 55 Ma and first phase of drifting was associated with abundant magmatism, probably related to the arrival of the Icelandic hot-spot. The continent-ocean-transition is modelled over a ca. 25 km wide zone, from an area with clearly defined stretched continental crust, to an area with oceanic crustal velocities and densities. The last phase of rifting is interpreted to be closely related to the development of crustal-scale detachment faults. The initiation of the episode may be referred to as passive rifting, whereas the breakup was actively related to the crustal detachment fault that was closest to the local injection centre on the Vøring Plateau. This detachment fault is defined as the continent-ocean-boundary (COB), since it delimits intruded continental crust to the southeast from anomalous oceanic crust to the northwest. The modelled P-wave velocities and crustal thickness indicates active upwelling of mantle and elevated mantle potential temperatures from breakup to ca. 5 Ma spreading.