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 inScandinavia with sedimentation across the Ediacaran–Cambrian transition without a significant hiatus. Geologicalinvestigations started in the 1930’s, but the Peninsula was first mapped in the 60’s. Ediacara-type fossils werefirst discovered in the late 80’s but recent discoveries will establish the Digermulen Peninsula as one of the mostsignificant Ediacaran sites in northern Europe. The parautochthonous strata are exposed in the Tanafjord areaalong the coast and in valleys on the east side of the Peninsula. The beds dip slightly to the west with the strikefollowing 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 astacked succession of diamictites of the Cryogenian Smalfjord Formation. After a hiatus follows the glaciogenicdiamictites of the Mortensnes Formation (~60 m thick), which is commonly seen to represent the ~582 Ma-oldGaskiers glaciation. Upwards, the contact to the overlying Stáhpogiedde Formation is not exposed locally, but hasbeen 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 upwardssuccession of laminated mudstone with intercalated sand bodies showing load structures. Preliminary microfossilssamples of the Member have so far proven almost barren, making dating more challenging. The basal part of thesucceeding Manndraperelva Member consists of three cycles; first a succession of reddish sandstone followed bytwo coarsening-upward cycles. Each starts with mudstone and fine sandstone and terminates in cross-beddedsandstone. The Ediacaran–Cambrian boundary is located within the third cycle, identified by the trace fossilTreptichnus pedum and associated trilobed trace fossils.The Digermulen Early Life Research Group has since2011 made significant new finds, and focused fieldwork aims to resolve tighter age constraints, provenance of thesediments and the range and diversity of the extended Ediacaran biota.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Annan geovetenskap och miljövetenskap (hsv//swe)

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

Nyckelord

Digermulen

Ediacaran

Finnmark

Norway

Earth Science with specialization in Historical Geology and Palaeontology

Geovetenskap med inriktning mot historisk geologi och paleontologi

Publikations- och innehållstyp

vet (ämneskategori)

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