Segmentation of Rifting and Magmatism along the Outer Vøring Basin, North Atlantic Margin, Norway

Laurent Gernigon1, Jean Claude Ringenbach2, Sverre Planke3, Helene Jonquet-Kolstø2, and Bernard Le Gall1. (1) Marine Geosciences, Brest University, IUEM, Place Nicolas Copernic, 29280 Plouzané, France, phone: 00(47) 51 50 35 40, fax: 00(47)51 50 37 75, laurent.gernigon@elfep.no, (2) Exploration, TotalFinaElf Petroleum Norge, P.O Box 168, N-4001, Stavanger, Norway, (3) Volcanic Basin Petroleum Research (VBPR), Forskningsparken, Gaustadalleen 21, N-0349, Oslo, Norway

The Norwegian Volcanic Rifted Margin has undergone several rifting phases since Caledonian time. The crustal and magmatic processes involved during the last phase of rifting, so called Atlantic Rifting, is ended by break-up at about 55Ma. In this context, the outer Vøring Margin have been investigated in detail for the preparation of the 16th Norwegian Round, using recent seismic and potential field data. Five NE-SW trending segments with different structural styles and evolution have been defined along the Outer Vøring Basin, they correspond to ridges and sub-basins separated by NW-SE oriented transfer zones: (1) Nyk High-Naglfar dome, (2) North Gjallar Ridge, (3) Gleipne Saddle, (4) South Gjallar Ridge and (5) Jan Mayen. In the Campanian-Paleocene, doming and listric faulting took place along the Naglfar and Gjallar segments contemporaneously with flexure and sagging in the central Vøring Basin. The southernmost Jan Mayen transform segment does not exhibit obvious rifted structures. However, normal and strike-slip faults are expected to be found beneath the volcanics. Deep smooth domal shape reflections, mainly observed beneath the North and South Gjallar Ridge, are interpreted as shear zone induced by boudinage and isostatic instability of the lower ductile crust during the Atlantic Rifting. The repartition of magmatic sills in the sedimentary basin and of the volcanics emplaced during the break-up suggests that important stretched areas may have a control on the late magma rising in the crust. Sills are mainly intruded in areas where the post rift subsidence is important and between the crustal domes.

AAPG Annual Meeting 2001: An Energy Odyssey