STRUCTURE AND EVOLUTION OF THE LOFOTEN CONTINENTAL-MARGIN, OFFSHORE NORWAY

The continental margin of western Norway, in the Lofoten area between 67-degrees-N and 69-degrees-30'N, is geologically complex. The continental shelf is narrow and dominated by rotated extensional fault blocks. The inner shelf has a series of deep half grabens infilled by thick sedimentary sequences, primarily of Cretaceous age. The outer shelf is dominated by a complex structural high, the Utrost Ridge, where crystalline basement rocks are at the seabed or covered by a thin veneer of sediments. Seaward of the Utrost Ridge, beneath the continental slope and extending out to water depths of approximately 3000 m, a possible Mesozoic rift basin is buried by Paleogene flow basalts and Cenozoic sediments several kilometers thick. The Lofoten Escarpment marks the approximate edge of the Tertiary oceanic crust. West of the Lofoten Escarpment a zone of seaward dipping reflectors is observed within the oceanic basalts, interpreted to be controlled by a series of landward dipping listric faults, The oceanic basalts are overlain by a sequence of Eocene and younger Cenozoic sediments. This paper discusses the observed geological structure and presents a general model for this part of the Norwegian margin.