Structural style and tectonic evolution of the northern part of the Bjørnøya Basin, South-Western Barents Sea, Norway

Abstract

Interpretation of new three-dimensional seismic data and regional two-dimensional seismic lines supported by well data reveal a complex tectonic evolution of the northern part of the Bjornoya Basin, SW Barents Sea. The study area has experienced at least three rift phases during the Late Paleozoic to Cenozoic time: Late Permian, Early Cretaceous and Early Cenozoic. The Late Permian Rift phase led to formation of large NE-SW-oriented faults dipping towards the west and offsetting the Permo-Carboniferous strata. The Early Cretaceous Rift phase resulted in a formation of two major sets of normal faults: NE-SW-oriented and WNW-ESE-oriented. These two sets of faults were reactivated later most likely during the Late Cretaceous. The youngest Rift phase took place in the Early Cenozoic as a result of the opening of the Norwegian-Greenland Sea and caused formation of NNW-SSE normal faults. The Bjornoya Basin developed during the Late Jurassic-Early Cretaceous as a major, asymmetrical half-graben with a highly faulted south-eastern margin defining a set of narrow terraces stepping down to the north-west, and generally unfaulted “flexural” margin in the NW. The present symmetric appearance of the Bjornoya Basin on seismic data is due to uplift of the Stappen High.