Effect of local variations of vertical and horizontal stresses on the Cenozoic structuring of the mid-Norwegian shelf

The mid-Norwegian margin has a complex history and has experienced several phases of changing horizontal and vertical stresses on regional and local scale during the Cenozoic time. In addition to regional stresses related the opening of the North Atlantic (i.e. ridge push) local variations in stress history may be important for development, distribution and reactivation of structures in the Vøring area in Cenozoic time. Presence and stability of flexural hinge zones between areas of relative uplift and subsidence have played an important role for focusing shallow horizontal stresses within the basins.
Results from modelling the effects of intra plate stress in a 2D section over the area show that this process may have given substantial vertical motions in certain areas of the mid Norwegian shelf, especially in the Hel- Vigrid- and Någrind Synclines where Cenozoic compressional structuring are observed. Our modelling take into account the tectonic and isostatic effects of loading, faulting and lithospheric thinning throughout the geological history, during and after several phases of extension prior to the Cenozoic compression. This approach emphasize the importance of the deformation history of the lithosphere compared to other studies that only take into account the effects of Cenozoic processes of compression and loading on the sedimentary units.