STRATIGRAPHY OF THE EDIACARAN AND BASAL CAMBRIAN OF THE DIGERMULEN PENINSULA, NORTHERN NORWAY

The succession of the Digermulen Peninsula in Finnmark, northern Norway, is the only fossiliferous site in Scandinavia with sedimentation across the Ediacaran–Cambrian transition without a significant hiatus. Geological investigations started in the 1930’s, but the Peninsula was first mapped in the 60’s. Ediacara-type fossils were first discovered in the late 80’s but recent discoveries will establish the Digermulen Peninsula as one of the most significant Ediacaran sites in northern Europe. The parautochthonous strata are exposed in the Tanafjord area along the coast and in valleys on the east side of the Peninsula. The beds dip slightly to the west with the strike following the coastline (ca. 045°). The Ediacaran succession is close to 1000 m thick and dominantly siliciclastic. It starts with interglacial sediments of the Nyborg Formation (tentatively the earliest Ediacaran), overlying a stacked succession of diamictites of the Cryogenian Smalfjord Formation. After a hiatus follows the glaciogenic diamictites of the Mortensnes Formation (~60 m thick), which is commonly seen to represent the ~582 Ma-old Gaskiers glaciation. Upwards, the contact to the overlying Stáhpogiedde Formation is not exposed locally, but has been shown to represent a hiatus followed by transitional fluvial to marine sediments of the Lillevannet Member. Ediacaran-type fossils appear in the succeeding Innerelva Member. This is a two-cycle deepening upwards succession of laminated mudstone with intercalated sand bodies showing load structures. Preliminary microfossils samples of the Member have so far proven almost barren, making dating more challenging. The basal part of the succeeding Manndraperelva Member consists of three cycles; first a succession of reddish sandstone followed by two coarsening-upward cycles. Each starts with mudstone and fine sandstone and terminates in cross-bedded sandstone. The Ediacaran–Cambrian boundary is located within the third cycle, identified by the trace fossil Treptichnus pedum and associated trilobed trace fossils.The Digermulen Early Life Research Group has since 2011 made significant new finds, and focused fieldwork aims to resolve tighter age constraints, provenance of the sediments and the range and diversity of the extended Ediacaran biota.