Structuring of the Northern Viking Graben and the More Basin; the influence of basement structural grain, and the particular role of the More-Trondelag Fault Complex

A comparison between structural histories of the Mere Basin of the Mid Norw egian shelf and the northernmost Viking Graben of the northern North Sea, s uggests that the basement structural grains of the two areas are not entire ly similar. However, considerable differences in timing and stretching magn itudes occur. These differences are clearly seen by Permian times, as contr asting stretching estimates are obtained for this period. The contrasts wer e even more pronounced in the Triassic-Cretaceous when extension was initia ted earlier and terminated later in the More Basin area than in the norther n Viking Graben. Furthermore, relatively pronounced late early Cretaceous a nd (?)Oligocene-Miocene inversion, which affected the More Basin, cannot be identified in the northern Viking Graben. Two reasons for these differences are proposed: firstly, the two basins are separated by segments of the More-Trondelag Fault Complex, and secondly, t hey had different positions in relation to the opening of the North Atlanti c. The More-Trondelag Fault Complex has been active during changing stress conditions since the Palaeozoic, and a correlation between dated events in the onshore part of the fault complex correlates well with the observations made in the offshore basins. This emphasises the regional significance of the More-Trondelag Fault Complex, and seismic activity in the area suggests that the fault complex is still active. (C) 1999 Elsevier Science Ltd. All rights reserved.