The Central Tertiary Basin of Spitsbergen: Sedimentary Development of a Sheared-Margin Basin

Abstract

Abstract The Central Tertiary Basin of Spitsbergen developed during the early phases of the opening of the Norwegian-Greenland Sea, so that the 2 km thick Paleocene-Eocene sedimentary succession in this basin accumulated during the transform motion between the Greenland and Barents Sea blocks. The internal details of the succession are therefore of special interest, since they provide a unique record of the behaviour of the flank of a sheared continental margin. The Paleocene-Eocene sediments were deposited mainly on coastal plains and wave or tide-dominated delta systems. The succession had three main stages of sedimentary development: a transgressive phase, during which deltas prograded repeatedly west and southwestward out across a shallow platform; and two regressive phases where larger delta systems built east and southeastward out from a westerly hinterland which was rapidly rising during the earliest transgressive stages of the West Spitsbergen Orogeny. The latest of these two regressive sequences, some 1.5 km thick, provides a particularly striking record of this western uplift. Its prodelta/lower delta front succession contains thick turbidites and slumped horizons, while the thick delta plain deposits show an extraordinary degree of soft sediment deformation.