Lithological description of subcropping Lower and Middle Triassic rocks from the Svalis Dome, Barents Sea

Eleven shallow cores display 315 m of the >700 m thick Lower and Middle Triassic succession of the Svalis Dome, a salt diapir in the central south-western Barents Sea. The Svalis Dome was uplifted in the late Mesozoic, and Triassic rocks subcrop below Quaternary till around the Upper Palaeozoic core of the dome. Deposition of the Triassic succession took place in deep shelf to basinal environments below storm wave base. The succession is dated by macrofossils and palynomorphs and can be assigned to four formations. The basal beds of the shaly greenish grey Havert Formation (Griesbachian) occur above Permian bioclastic carbonate. The Klappmyss Formation (Smithian) in the lower part contains gravity flow sands deposited as submarine fans possibly triggered by tectonic movements along the adjacent fault zones overlain by silty claystones. An organic-rich dark shale unit is here formally defined as the Steinkobbe Formation, and was deposited in a large bight by restricted water circulation. The Snadd Formation, on top, represents a marine shelf unit deposited in front of an emerging land area in the north-east. A minimum of six higher order transgressive-regressive sequences are recognized at the Svalis Dome and these are correlated with other Arctic areas.