Interpretation of depth to the magnetic basement in the northern Barents Sea.

Abstract

The Geological Survey of Norway (NGU), in co-operation with Geco, conducted aeromagnetic measurements over the northern Barents Sea on behalf of the five oil companies Statoil, Norsk Hydro, Esso Norge, Elf Aquitaine Norge and Norsk Agip. The survey area, situated between 74 gr 30' and 77 gr.N, and 15 gr and 32 gr E, covered some 135 000 km2 with 34000 km of aeromagnetic profiles. The study area embraces the Svalbard Platform, the Hopen High, the Sørkapp Basin, the Bjørnøya-Sørkapp High and the continent-ocean transition zone, as well as other major structural features. The main result of the study is a contour map of the depth to the top of the magnetic basement. The interpreted depths to the magnetic basement exceed 10 km in the Sørkapp Basin, in parts of Storfjorden, and towards the Olga Basin. The crystalline basement is found at depths of less than 2 to 3 km at the Bjørnøya-Sørkapp High and the Hopen High, and at depths of about 6 km on the Gardarbanken High. Depths in the area of the central platform vary smoothly and gradually from 6 to 9 km. It is believed that in some areas pre-Permian sediments may consti\u00FFtue more than half of the total sedimentary column. The continent-ocean transition zone is clearly reflected in both the magnetic map and the magnetic basement map. Strong gradients in the contour map of depth to magnetic basement coincide with the well-known Bjørnøya-Sørkapp and the Hornsund-Fault-Zones. it is therefore believed that the strongest ........