Temporal constraints on basin inversion provided by 3D seismic and well data: a case study from the South Viking Graben, offshore Norway

Three-dimensional (3D) seismic, well and biostratigraphic data are integrated to determine the timing of inversion on the hangingwall of the South Viking Graben, offshore Norway. Within the study area two, NW-SE to NE-SW trending normal faults are developed which were active during a Late Jurassic rift event. In the hangingwall of these faults asymmetric, 2-5 km wide anticlines are developed which trend parallel to the adjacent faults and are interpreted as growth folds formed in response to compressional shortening (inversion) of the syn-rift basin-fill. Marked thickness variations are observed in Late Jurassic and Early Cretaceous growth strata with respect to the inversion-related folds, with seismic data indicating onlap and thinning of these units across the folds. In addition, well data suggests that not only are erosional surfaces only locally developed towards the crests of the folds, but these surfaces may also truncate underlying flooding surfaces towards the fold crests. Taken together, these observations indicate that inversion and growth of inversion-related structures initiated in the late Early Volgian and continued until the Late Albian. Furthermore, it is demonstrated that individual folds amplified and propagated laterally through time, and that fold growth was not synchronous across the study area. This study demonstrates that the temporal evolution of structures associated with the inversion of sedimentary basins can be accurately determined through the integration of 3D seismic, well and biostratigraphic data. Furthermore, this study has local implications for constraining the timing of inversion within the South Viking Graben during the Late Mesozoic.