​

Our work emphasizes identifying pinch-outs and erosion areas, providing improved visualization of potential stratigraphic traps.

​

The interpreted surface merges the Top of the Permian Zechstein formation with the basement and therefore represents the base of the interval of interest for the Triassic, Jurassic, and Cretaceous ages. Depending on the location within the Zechstein Permian basin, the lithology of the formation varies—carbonates and sandstones within intra-basin highs transition to evaporites, such as halite and anhydrites, within the slopes and depressions of the paleo-Permian basin. Mobilized halite forms large diapirs, while strikes of anhydrites complicate the seismic imaging within the Zechstein Supergroup. Bright reflectors within halite intervals often indicate lithological changes. Due to gravitational gliding and differential loading, mobile salt forms various structural features. Clark and Jackson recently published work exploring how syn-depositional salt flow influenced the post-depositional deformation of the salt and its overburden. Numerous Triassic minibasins exhibit strata onlapping the edges of salt deformed by differential loading. Analyzing relationships between reflectors within these basins has helped define areas where bright reflectors correspond not to salt but to Triassic sands, in which oil and gas discoveries have been made in the Southern Viking Graben. These sands are confirmed by well data.

​

In the Central North Sea, grabens are observed to have formed due to salt diapir collapses. Jurassic and Cretaceous onlaps are often visible on the sides of post-depositional salt diapirs.

​

Salt structures began forming during syn-depositional Permian rifting. Early Permian rifting, associated with the development of the Central Graben, influenced the location and extent of the Zechstein Supergroup evaporites, directly affecting lithological distribution within the Zechstein Supergroup. Carbonate- and anhydrite-rich units were deposited at the basin margins and intra-basin structural highs during highstands, while halite- and K–Mg-rich salt units were deposited in deeper basins during lowstands (Joffe and Jackson, 2022).

​

Within structural highs such as Utsira, Jurassic or Triassic strata are patchily distributed. At the apex of these highs, Cretaceous sediments often directly overlie the basement, with Jurassic and Triassic strata fully eroded. Well data was analyzed to confirm such areas. Near Utsira, numerous patchy grabens are preserved. Published gravity data (Jan Erik Lie, Espen Harris Nilsen, 2016) indicates the location of grabens within the granitic basement and aids in distinguishing them in areas with unclear seismic imaging. The grabens are filled with Permian and Triassic sediments, with a focus on grabens containing Triassic-age sediments, as numerous oil and gas discoveries have been made there (e.g., Edvard Grieg, Luno).

​

• Clark, J.A., Stewart, S.A., & Cartwright, J.A. (1998). Evolution of the NW margin of the North Permian Basin, UK North Sea. Journal of the Geological Society of London, 155, 663–676.

• Marín, D., Cardozo, N., & Escalona, A. (2022). Compositional variation of the Zechstein Group in the Norwegian North Sea: Implications for underground storage in salt caverns.

• Jackson, C., Evrard, E., Elliott, G., & Gawthorpe, R. (2014). Lithology distribution in the Zechstein Supergroup and controls on rift structure: Greater South Viking Graben, Northern North Sea.

• Joffe, A., Jackson, C.A.-L., & Pichel, L.M. (2022). Syn-depositional halokinesis in the Zechstein Supergroup (Lopingian) controls Triassic minibasin genesis and location. First published: 25 November 2022.