Crustal structure and evolution of the outer Møre Margin, NE Atlantic

Abstract

Five regional Ocean Bottom Seismic profiles from the northwestern part of the Møre Margin, NE Atlantic, have been modeled with regard to crustal structure, and the interpretations have been supported by the use of multi-channel seismic and potential field data. The chi-squared values (uncertainty) for the studied profiles are generally in the range 1–3, and the uncertainty in the Moho depth is estimated to ± 1 km. The Continent–Ocean-Transition is found to be relatively sharp (10–40 km wide) expressing a change in physical properties corresponding to felsic continental crust along the landward part of the marginal high ( V p = 6.2–6.5 km/s), and thick, mafic oceanic crust further northwestwards. The Early Eocene breakup was associated with excessive magmatism, and the models document direct continuity between this magmatism and a lower crustal high-velocity layer in the Møre Basin ( V p = 7.1–7.3 km/s), suggesting a genetic link. The Jan Mayen Lineament is observed across the entire study area as northeastward termination of the lower crustal body, as well as structuring in the top of the crystalline basement and the Moho. We present a speculative model involving lower crustal bodies of eclogites ( V p > 8 km/s) inferred in the easternmost part of the Møre Basin linking the Jan Mayen Lineament to the post-Caledonian Nordfjord-Sogn Detachment.