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Sabellidites cambriensis is a tubular non-mineralized metazoan that appears as compressed ribbon-shaped imprints with transverse wrinkling, thick walls and an even tube diameter of up to 3 mm. The distribution of Sabellidites is investigated in three Ediacaran–Cambrian sections on the Digermulen Peninsula in Arctic Norway, spanning the Manndrapselva Member of the Stáhpogieddi Formation and the lower member of the Breidvika Formation. Here, the Ediacaran–Cambrian boundary is located in the lower part of the upper parasequence (third cycle) of the Manndrapselva Member. Specimens of Sabellidites are rare but consistently present close to the lowest level of Treptichnus pedum and upsection, whereas the taxon is common and abundant in the lower part of the lower member of the Breidvika Formation, with an upper record at c. 55 m above the base. The range is comparable with that of the GSSP section in Newfoundland, Canada, establishing Sabellidites as an index fossil for the lowermost Cambrian. In the Manndrapselva Member, Sabellidites co-occurs with the acritarch Granomarginata, indicative of the lowermost Cambrian Granomarginata Zone, whereas in the Breidvika Formation it co-occurs with Asteridium. Sabellidites is widely distributed in Baltica, through the Rovnian and Lontovan regional stages but confined to the Fortunian global stage. In its lower range, Sabellidites is associated with a Treptichnus pedum trace fossil association and a depauperate leiosphaerid acritarch assemblage, followed by a Granomarginata assemblage. In its upper range, Sabellidites co-occurs with acritarchs of the Asteridium–Comasphaeridium Zone and the tubular foraminiferan Platysolenites. In Baltica, Sabellidites is a useful index fossil., The Digermulen Early Life Research Group acknowledges funding to Anette E. S. Högström from the Norwegian Research Council (NRC, project number 231103). Travel support was given to Frida Hybertsen by the Department of Earth Sciences, Palaeobiology, Uppsala University. T. P. & S. J. acknowledge funding from ‘Ministerio de Economía. Industria y Competitividad’ grant CGL 2017-87631-P.To view supplementary material for this article, please visit https://doi.org/10.1017/S0016756821001187

New information on acritarchs from the Duolbagaisa Formation, Digermulen Peninsula, Arctic Norway, enable recognition of the three Cambrian Series 2 acritarch-based zones: the Skiagia ornata-Fimbriaglomerella membranacea, Heliosphaeridium dissimilare-Skiagia ciliosa and Volkovia dentifera-Liepaina plana Assemblage zones. Acritarchs of the Skiagia ornata-Fimbriaglomerella membranacea Zone (Cambrian Stage 3) appear near the base of the unit, close to an undetermined trilobite. In the Upper Member of the Duolbagaisa Formation, in levels with Kjerulfia n. sp. and Elliptocephala n. sp., appears an assemblage with abundant Skiagia ciliosa, indicative of the Heliosphaeridium dissimilare-Skiagia ciliosa Zone. A few metres higher appear Liepaina plana, Heliosphaeridium notatum and Retisphaeridium dichamerum, which indicate the Volkovia dentifera-Liepaina plana Zone (Cambrian Stage 4). The transition between the Duolbagaisa Formation and the overlying Kistedalen Formation is marked by the appearance of Comasphaeridium longispinosum, Multiplicisphaeridium llynense and Eliasum llaniscum, diagnostic of the Miaolingian Series. This coincides with the disappearance of Skiagia; occurrences of Skiagia in Miaolingian strata consist of reworked material related to the Hawke Bay regression at the Cambrian Stage 4-Wuliuan transition. The absence of Skiagia in higher levels of the Duolbagaisa Formation and Kistedalen Formation suggests that no unconformity formed during the Hawke Bay regression in this area. The chronostratigraphical significance of the Skiagia ornata-Fimbriaglomerella membranacea, Heliosphaeridium dissimilare-Skiagia ciliosa and Volkovia dentifera-Liepaina plana zones is critically analysed. Correlation of the Duolbagaisa Formation with peri-Gondwanan terrains of Avalonia and Iberia is established. The Digermulen Peninsula has great potential as a reference section for establishing a Cambrian chronostratigraphy based on acritarchs.

Results of in situ U-Pb dating of calcite spherulites, cone-in-cone (CIC) calcite and calcite fibres from a calcareous concretion of the upper Ediacaran of Finnmark, Arctic Norway, are reported. Calcite spherulites from the innermost layers of the concretion yielded a lower intercept age of 563 +/- 70 Ma, which, although imprecise, is within uncertainty of the age of sedimentation based on fossil assemblages. Non-deformed CIC calcite from the bottom part of the concretion yielded an age of 475 +/- 25 Ma, which is interpreted as the age of CIC calcite formation during a period of fluid overpressure induced during burial of the sediments. Deformed CIC calcite from the top part of the concretion yielded an age of 418 +/- 23 Ma, which overlaps with a known Caledonian tectono-metamorphic event, and indicates a potential post-depositional overprint at this time. Calcite fibres that grew in small fissures along spherulite rims, which are interpreted as a recrystallization feature during deformation and formation of a cleavage, gave an imprecise age of 486 +/- 161 Ma. Our results show that U-Pb dating of calcite can provide age constraints for ancient carbonates and syn- to post-depositional processes that operated during burial and metamorphic overprinting.