Changes of sediment composition at the dawn of animal life: Insights from the Ediacaran‒Cambrian boundary section of the Digermulen Peninsula (Finnmark, Arctic Norway)

• The Digermulen Peninsula in northern Norway is the only fossiliferous site in Scandinavia with sedimentationacross the Ediacaran–Cambrian transition without a significant hiatus. Furthermore, it is the only locality inScandinavia where Ediacara-type fossils have been found. The site is located at the edge of Baltica during theEdiacaran–Cambrian transition, where potentially the dramatic climatic turnover from icehouse to greenhouseconditions can be deduced and tied to large-scale plate tectonics. Since 2011, studies by the Digermulen EarlyLife Research Group have recorded significant new finds, promising to establish the site as a significant Ediacaranbiota locality. The Ediacaran succession is about 1000 m thick. Ediacara-type fossils occur in the InnerelvaMember of the Stáhpogiedde Formation. Discoidal fossils dominate the Ediacaran assemblage, although apotentially much greater diversity is suggested because of the recent discovery of a frond-shaped fossil. TheEdiacaran–Cambrian boundary is located within the Manndraperelva Member of the Stáhpogiedde Formation,based on biostratigraphic age control, followed by the Lower Cambrian Breidvika Formation. The successionconsists mainly of quartz-rich sandstones and mudrocks. Deposition took place in various environments, includingfluvial, shallow marine and deeper marine settings. As shown by previous studies using palaeocurrent data,sediment supply was from the Baltic Shield toward the passive margin of Baltica in pre-Ediacaran time. At onepoint within the Ediacaran succession, it shifted by 180 degrees due to the newly formed Timanian orogen. Thisorogen formed in north-eastern Baltica during the late Neoproterozoic and caused a shift in sediment transportdirection and change in source area due to the formation of the Timanian foreland basin to the east of DigermulenPeninsula. In order to track sediment supply and to test current palaeotectonic models a multi-disciplinaryapproach on late Neoproterozoic and Cambrian sediments of the Digermulen Peninsula has been applied. Themethods include, amongst other things, thin section petrography, bulk rock geochemistry (XRF, ICP-MS, ICPOES),bulk rock mineralogy (XRD), heavy mineral analysis, single grain chemistry (EMP, LA-ICP-MS) and zirconU-Pb geochronology.

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 Peninsula

Ediacara

provenance

Norway

Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics

Geovetenskap med inriktning mot mineralogi, petrologi och tektonik

Publikations- och innehållstyp

vet (ämneskategori)

kon (ämneskategori)