The Vikinghøgda Formation - The New Lower Triassic Type Section for Central and Eastern Svalbard

Although the P-T boundary is exposed in many places in the world, few show good possibilities for detailed description of the boundary beds. The main reason is that the boundary is often associated with an extensive hiatus, omitting both the latest Permian and earliest Triassic succession. This is partly also the case in the three widespread basins of East Siberia, Arctic Canada and Svalbard of the Barents Shelf. At the margin of these arctic basins large parts of the succession are missing, however, the P-T boundary beds may be preserved in the central parts of the individual basins. In all these basinal areas the ammonoid Otoceras occurs in the lowermost part of the Triassic succession. However other age diagnostic fossils are sparse, except for palynomorphs, which are most useful as basinal facies indicators. Age diagnostic macrofossils are sparse in the latest Permian beds, and again only palynomorphs give any help in refining our understanding of the boundary beds. The Barents Sea covers an extensive continental shelf with thick Permian and Triassic successions. The archipelago of Svalbard forms the northwestern corner of this shelf and gives excellent opportunities to study the P-T boundary beds. A stable platform formed during the Permian, which slowly covered major parts of the Barents Sea Shelf, forming an extensive carbonate ramp. Towards the late Permian siliciclastic sediments dominated with cherty shale being the main lithology. These weathering resistant rocks form a pronounced contrast with the soft shales and sandstones of the overlying lower Triassic succession. Pronounced hiati occur at several distant localities on Svalbard, like eroded Permian limestones, not transgressed before the Smithian at Edgeøya; the missing latest Permian succession at Bjørnøya transgressed in the Dienerian, and the condensed Permian section at the Sørkapp - Hornsund High on southern Spitsbergen also transgressed in the Dienerian. In the central part of the basin we also observe a clear shift in lithology at the P/T boundary, although, no erosional break is seen. Palynomorphs, including a peculiar fungal bloom around the boundary beds may indicate a nearly continuous, but punctuated, succession. We have performed detail studies of sedimentology, mineralogy, macropalaeontology, micropalaeontology (mainly conodonts), palynology and magnetostratigraphy across the boundary and throughout the Triassic succession of Svalbard. Our poster and presentation will present these Artic successions, which are good candidates for type areas for understanding the P-T boundary, and the Triassic succession of the Boreal seas.