Sammendrag
The Hoop Fault Complex is an old zone of weakness in SW Barents Sea which intersects Bjarmeland Platform and separates Maud Basin from Mercurius High. Reactivations during its long-lived activity have brought to the complex of geometry, style and geological history of this fault complex. A set of 2D and 3D seismic lines has been interpreted to map and characterize the structural geometry, genesis and evolution of the Hoop fault Complex.
The Hoop Fault Complex is an obviously extensional fault complex with graben system. It can be divided laterally and vertically into distinct major segments of different fault geometry, orientation and style. Laterally, this fault complex comprises NE-SW trending half graben in the south, NE-SW trending full graben in the central part and N-S trending full graben in the north. Vertically, this fault complex consists of several depth-dependent segments which are characterized by different fault geometry and separated by detachments. The main detachment coincides with upper Carboniferous-lower Permian carbonate-evaporite succession separating late Carboniferous interval from the post-early Permian interval. Late Carboniferous interval is characterized by a set of extensional planar normal faults defining a wide graben with tilted fault blocks and faulted platform which are formed by late Carboniferous major rifting. Post-early Permian interval is characterized by complex geometry of moderate-steeply dipping, slightly curved, extensional master normal faults which are segmented into three depth-dependent intervals. Each depth-dependent interval has different normal fault characteristics which are influenced by different reactivation process, from growth faulting in early-middle Triassic, mild inversion in middle-earliest late Triassic and major extension in late Jurassic-early Cretaceous. Organic rich-shales within upper Permian Ørret Formation and middle Triassic Snadd-Kobbe Formations have acted as minor detachments separating mentioned depth-dependent intervals.
Evolution of the Hoop Fault Complex in study area was started from late Carboniferous ESE-WNW regional rifting which was followed by thermal subsidence in early-late Permian. No indication of faulting related to late Permian-early Triassic regional rifting can be observed in study area. Growth faulting active during early-middle Triassic which was followed by mild inversion related to the NW-SE head-on contraction in middle-earliest late Triassic. Subsidence occurred during early-middle Jurassic, which was broke by the late Jurassic-early Cretaceous NW-SE rifting. Late Cretaceous was marked by the regional uplift and erosion, which was followed by Paleogene subsidence and Neogene glaciation uplift and erosion.