The Mortensnes Formation: A Comparative Study

On the Digermulen Peninsula, the succession starts with the classic Neoproterozoic glacial tillite of the Mortensnes Formation (Fig. 3). This tillite has traditionally been tentatively correlated by many workers (e.g., Rice et al. 2011, and references therein) with the type 'Gaskiers' glaciogenic succession in Newfoundland, which is between 584 and 582 Ma old, based on zircon U–Pb ages from intercalated ash beds (Bowring et al. 2002). The Mortensnes Formation is separated downwards from the 'Marinoan' (Cryogenian) glacial deposits of the Smalfjord Formation by some 400 m of siliciclastic sediments of the Nyborg Formation (Fig. 2). Nystuen et al. (2016) recently suggested that the Mortensnes Formation probably correlates with the 'Marinoan'
Sandstones of the Lillevannet Member are very mature and were deposited in fluvial and shallow marine environments. These sediments are conformably overlain by mudrocks and sandstones of the Innerevla Member yielding Ediacara-type fossils. The latter, originally described by Farmer et al. (1992), consist of various genera of discoidal forms, but this is in need of more documentation (Fedonkin et al. 2007, p. 199). During recent field expeditions by the "Digermulen Early Life Research Group", where the applicant is a member, new Ediacara-type fossils and other traces of early life were discovered in sections along the eastern part of the peninsula (Fig. 3), the only area in Scandinavia where Ediacara-type fossils have been found. Interestingly, the apparent lack of trace fossils may be an indication that the Ediacara-type fossils from the Digermulen Peninsula in fact are older than comparable ones from the White Sea (>555 Ma), which also could explain the lack of more complex forms such as Dickinsonia (Fig. 2). Other explanations are possible, including lack of preservation (see recent discussion in Boag et al. 2016). Narbonne (2005) included the Innerelva Member fossils in his category of Fermeuse-style preservation,