Magmatic domes and the initiation of oceanic processes at the Norwegian margin

The Wilson-cycle is a conceptual model accounting for the assembly, dismembering, and separation of continental masses on Earth. Yet, beyond the widely used concept, the mechanics of the final breakup of continents as a fundamental step remain weakly constrained. The beginning of oceanic accretion is nowhere firmly observed. It is usually reported as corresponding to gradual structural and/or magmatic variations, but no specific geometry has been identified as witnessing the actual onset of an oceanic spreading ridge. Based on a deep penetrating high resolution seismic reflection dataset, this contribution reports new geometries from the outer domain of the Mid-Norwegian rifted margin. A series of systematic magma-related features is observed and described within the context of the lithospheric breakup. The reported geometries may help better understand the transition from rift to drift processes, including possible domes of accumulated frozen magma, fractures and dikes radiating systems, intrusives and lava flows.