Nature of Palaeozoic extension in Lofoten, north Norwegian Continental Shelf: insights from 3-D seismic analysis of a Cordilleran-style metamorphic core complex

Abstract

Analyses of 3-D seismic data reveal that pre-Triassic basins are present underneath the Mesozoic North Træna Basin (Lofoten Margin, Norway). These are linked to a Cordilleran-style metamorphic core complex that developed in Palaeozoic times, including rotated fault blocks with hanging wall ‘growth’ wedges, bounded by listric faults that sole into a sub-horizontal detachment. On the basis of similarity in age, structural style and transport direction, we propose a kinematic link with a Permian mylonitic detachment documented onshore. This study presents the first offshore evidence for Palaeozoic detachment faulting, elucidating the mechanisms behind the long-lived exhumation history of the Lofoten basement.