Development of a Late Jurassic shallow marine system controlled by footwall uplift in the Froan Basin and Frøya High, offshore Mid-Norway

The Froan Basin, located on the proximal platform area on the Mid-Norwegian Continental Shelf, contains petroleum-bearing Upper Jurassic syn-rift deposits. Additional isolated Upper Jurassic shallow marine sand bodies have been identified on the Frøya High, but the platform area remains poorly understood in terms of its Late Jurassic tectono-stratigraphic evolution. Improving our understanding, and in particular how fault activity and rift-shoulder uplift influenced rift physiography and the presence of shallow marine reservoirs, is crucial when assessing hydrocarbon prospectivity. In this study, we present a model for the Late Jurassic rift development of the Froan Basin and Frøya High based on seismic interpretation, well data, and reverse subsidence modelling. We show that during the Late Jurassic to Early Cretaceous, major footwall uplift and exposed the western margin of the Froan Basin and Frøya High formed an intra-rift footwall island. Shallow marine areas to the east, immediately adjacent to the footwall island, accumulated shoreface sediments supplied from the eroded footwall. We therefore suggest that the extent of the Late Jurassic shallow marine system was controlled by the magnitude of footwall uplift and geomorphology of the western margin of the platform area.