Rift architecture of the Lofoten-Vesterålen margin, offshore Norway

Abstract

The Lofoten-Vesterålen margin (LVM) located offshore northern Norway, is the least explored and understood margin segment within the Norwegian passive margin. Three previous models have been proposed to explain the evolution and architecture of the margin: 1) segmentation by NW–SE-striking transform faults; 2) temporal and spatial segmentation of different phases of rifting; and 3) segmentation by an E–W-striking accommodation zone. In this study, we utilize industry 2D seismic data, potential field data, and well and outcrop published data information to revise the evolution, structural styles, and segmentation of the margin.The rift evolution of the LVM consists of: a pre-rifting/marginal rifting event during the Triassic and Jurassic, shown by the localized distribution of wedge-shaped sedimentary packages; a main-rift event during the Early Cretaceous with the development of large half-graben depocenters; and a post-rift event during Late Cretaceous to present. Three margin segments were defined (Southern Lofoten, Northern Lofoten and Vesterålen-Andøya) based on variations in the structural styles and basin-fill along the margin. The margin segments are separated by two time-transgressive NW–SE-striking transfer zones. The first transfer zone (North Lofoten transfer zone) separated the Southern Lofoten segment from the Northern Lofoten-Vesterålen-Andøya segments in the Late Jurassic. The second transfer zone (Vesterålen Transfer zone) separated the Northern Lofoten from the Vesterålen-Andøya segments in the Early-Late Cretaceous.The LVM is classified into three distinct rift domains: proximal, necking and oceanic. Each of these domains consistently shows prominent structural similarities across the margin. The necking domain is suggested as the most hydrocarbon prospective area based on similarities with the same domain in mid-Norway where source rock reservoir preservation is the highest.