Rare earth elements and neodymium and strontium isotopic constraints on provenance switch and post-depositional alteration of fossiliferous Ediacaran and lowermost Cambrian strata from Arctic Norway

• Upper Ediacaran–lowermost Cambrian mudstones from northern Norway were studied. Ediacara-type macrofossils are associated with a well-oxygenated environment. Neodymium isotopic data indicate terrigenous detritus old continental crust. Brief provenance switch during post-Gaskiers time. Rb–Sr whole-rock isotope system was reset the Scandian Orogeny. The Digermulen Peninsula in northeastern Finnmark, Arctic Norway, comprises one of most complete Ediacaran–Cambrian transitions worldwide nearly continuous record micro- and interval diversification complex life. Here, we report on post-depositional alteration argillaceous using rare earth elements Sm–Nd systematics to provide an environmental context better understand this important transition Earth’s history. studied sections comprise mid-Ediacaran glacial–interglacial cycle, including Nyborg Formation (ca. 590 Ma) Mortensnes (related ca. 580 Ma-old Gaskiers glaciation), Stáhpogieddi 560–537 Ma), which yields fossils Indreelva Member contains boundary Manndrapselva basal part informal Lower Breidvika member 537–530 Ma). Three sample groups, (1) formations, (2) lowermost five samples (3) remaining as well members, can be distinguished, belonging distinct depositional units. All have negative ε Nd (T) values (−6.00 − 21.04) indicating dominant input crust affinity. Significant shifts related changes sediment source, i.e. Svecofennian province vs Karelian plus addition likely some juvenile (late Neoproterozoic volcanic) material, probably reflect palaeotectonic reorganisation along Iapetus-facing margin Baltica. combined all yield errorchron age about 430 Ma reflecting resetting systems tectono-metamorphic event Gaissa Nappe Complex Finnmark. Preservation palaeopascichnids coincides sedimentation regimes groups 2 3 while other fossils, e.g. Aspidella -type frondose forms, limited group 3. Our results similar those earlier studies East European Platform suggesting oxic seafloor conditions late Ediacaran.