New occurrences and extension of the stratigraphical range of discoidal Ediacara‑type fossils on the Digermul Peninsula, northern Norway

• In Scandinavia the evolutionary events across the Ediacaran–Cambrian transition can only be studied in continuous section on the Digermul Peninsula, northern Norway, in the siliciclastic Stáhpogiedde Formation. This roughly 500 m-thick unit comprises, in ascending order, the Lillevannet, Innerelva and Manndraperelva members. Trace fossils, including Treptichnus pedum, and organic-walled microfossils, including Granomarginata prima, position the base of the Cambrian in the upper part of the Manndraperelva Member. Some 20 years ago discoidal Ediacara-type fossils were found in the middle part of Innerelva Member. Recent field seasons have provided abundant new material of Aspidella-type fossils and extended their stratigraphical range to within about 15 m above the Lillevannet Member. The exclusive presence of discoidal forms may reflect a taphonomic bias and/or be evidence of a greater age than that of the more diverse Ediacaran assemblages. That the latter may be the case is indicated by the stratigraphic proximity of the lowest occurrences of Aspidella to the Mortensnes diamictite, recently tentatively considered a Gaskiers glaciation equivalent (c.580 Ma). This raises the question of hitherto unrecognised breaks in sedimentation in the Stáhpogiedde Formation. In order to explore this question we have sampled the succession for organic-walled microfossils, detrital mineral geochronology and sediment geochemistry.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Geologi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Geology (hsv//eng)

Nyckelord

Earth Science with specialization in Historical Geology and Palaeontology

Geovetenskap med inriktning mot historisk geologi och paleontologi

Publikations- och innehållstyp

vet (ämneskategori)

kon (ämneskategori)