Influence of fault reactivation during multiphase rifting: The Oseberg area, northern North Sea rift

During the Middle Jurassic - Early Cretaceous rifting, faults of all orientations (N-S, NW-SE and NE-SW) were active. However, faults initiated during the Middle Jurassic - Early Cretaceous rifting show mainly N-S orientation, indicating E-W extension during this phase. These observations suggest a reorientation of the stress field from E-W during the Permian - Early Triassic rift phase to NE-SW during inter-rift fault growth and back to E-W during the Middle Jurassic - Early Cretaceous rift phase in the Oseberg area. Hence, the current study demonstrates that rift activity between established rift phases can locally develop faults with new orientations that add to the geometric and kinematic complexity of the final fault population.