Land-offshore tectonic links in western Norway and the northern North Sea

Aeromagnetic and marine gravity data sets for the northern North Sea and we stern Norway have been interpreted in terms of land to offshore tectonic li nks. The data allow identification of linking-structures both in crystallin e basement and overlying sedimentary rocks and consequently facilitate a mo re comprehensive interpretation of regional structural features and trends. With the help of bathymetric data in the inshore region, major fault struc tures can be traced between western Norway and the offshore region west of the Oygarden Fault Zone. In this way spatial and chronological links have b een established between tectonic events recognized on land and the developm ent of the North Sea Basin. An interpretation of basement geology is propos ed for the region between western Norway and the Uer Terrace. This is compl emented with a depth to top crystalline basement map covering the North Sea Basin between the Uer terrace and the East Shetland Basin. Two regional NW -SE lineaments were recognized offshore western Norway and given the names Marflo Lineament and Troll Lineament. The Marflo Lineament is interpreted t o be a Caledonian or older zone of weakness that accommodated development o f a 20-30 km offset in the Jurassic Viking Graben axis. The lineament can b e traced into the North Atlantic where it parallels oceanic fracture zones and transform faults. The Troll Lineament relates to a deep geological disc ontinuity crossing the Uer and Lomre Terraces. A grouping of earthquake epi centres along part of the lineament suggests that the discontinuity is tect onically active.