Polygonal fault systems on the mid-Norwegian margin:: a long-term source for fluid flow

2D and 3D seismic data from the mid-Norwegian margin show that polygonal fault systems are widespread within the fine-grained, Miocene sediments of the Kai Formation that overlie the Mesozoic/Early Cenozoic rift basins. Outcropping polygonal faults show that de-watering and development of polygonal faults commenced shortly after burial. On the other hand, the polygonal fault system's stratigraphic setting, upward decreasing fault throw and the association with fluid flow features that are attributed to de-watering of the polygonal fault systems shows that polygonal faulting and fluid expulsion is an ongoing process since Miocene times.