Shallow stratigraphic cores NW of Bjørnøya, results and implications

Abstract

Two shallow boreholes, 7418/01-U-01 and 7517/12-U-01, were in 1994 drilled by IKU / SINTEF on behalf of the Norwegian Petroleum Directorate (NPD) northwest of Bjørnøya in the western Barents Sea. These were part of a program totalling nine boreholes at six different locations between Bjørnøya and Svalbard. This area is not opened for petroleum activity, and the shallow boreholes were aimed at providing new data and increased geological knowledge. The two drill sites are located were reflections are subcropping below the late Neogene and Quaternary overburden, and in two different sub-basins within the Hornsund fault complex. Borehole 7418/01-U-01 was drilled at a water depth of 181.5m. Total depth from seabed was 126.15m and 113.3m of cores were cut. Borehole 7515/12-U-01 was drilled at a water depth of 156m. Total depth from seabed was 200m and 87.8m of cores were cut. Borehole 7418/01-U-01 penetrates Late Paleocene to Early Eocene strata, while borehole 7517/12-U-01 penetrates Late Paleocene strata. The cores show a diverse set of sedimentary features, ranging from primary depositional structures to detrimental bioturbation. The cores are dated to Paleogene age and show a variety of sedimentary features such as ample bioturbation, ripples and various cross stratifications. The lithology varies from mud to several sandy intervals and thinner beds of conglomerate. The findings indicate a deep marine setting for core 7418/01-U-01 and a shallow marine setting for 7517/12-U-01. This suggests that core 7418/01-U-01 correlate to the deep marine paleoenvironment to the south, while core 7517/12-U-01 correlates to the shallow marine paleoenvironment of Svalbard.