| 1. |
- Agic, Heda, et al.
(author)
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Late Ediacaran occurrences of the organic-walled microfossils Granomarginata and flask-shaped Lagoenaforma collaris gen. et sp. nov.
- 2022
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In: Geological Magazine. - : Cambridge University Press. - 0016-7568 .- 1469-5081. ; 159:7, s. 1071-1092
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Journal article (peer-reviewed)abstract
- New occurrences of flask-shaped and envelope-bearing microfossils, including the predominantly Cambrian taxon Granomarginata, are reported from new localities, as well as from earlier in time (Ediacaran) than previously known. The stratigraphic range of Granomarginata extends into the Cambrian System, where it had a cosmopolitan distribution. This newly reported Ediacaran record includes areas from Norway (Baltica), Newfoundland (Avalonia) and Namibia (adjacent to the Kalahari Craton), and puts the oldest global occurrence of Granomarginata in the Indreelva Member (< 563 Ma) of the Stahpogieddi Formation on the Digermulen Peninsula, Arctic Norway. Although Granomarginata is rare within the assemblage, these new occurrences together with previously reported occurrences from India and Poland, suggest a potentially widespread palaeogeographic distribution of Granomarginata through the middle-late Ediacaran interval. A new flask-shaped microfossil Lagoenaforma collaris gen. et sp. nov. is also reported in horizons containing Granomarginata from the Stahpogieddi Formation in Norway and the Dabis Formation in Namibia, and flask-shaped fossils are also found in the Gibbett Hill Formation in Newfoundland. The Granomarginata-Lagoenaforma association, in addition to a low-diversity organic-walled microfossil assemblage, occurs in the strata postdating the Shuram carbon isotope excursion, and may eventually be of use in terminal Ediacaran biostratigraphy. These older occurrences of Granomarginata add to a growing record of body fossil taxa spanning the Ediacaran-Cambrian boundary.
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| 2. |
- Agic, Heda, et al.
(author)
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Life through an Ediacaran glaciation : Shale- and diamictite-hosted organic-walled microfossil assemblages from the late Neoproterozoic of the Tanafjorden area, northern Norway
- 2024
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In: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier. - 0031-0182 .- 1872-616X. ; 635
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Journal article (peer-reviewed)abstract
- New organic-walled microfossil (OWM) assemblages are reported from upper Neoproterozoic glacial and interglacial siliciclastic deposits in Finnmark, northern Norway. A nearly continuous sedimentary succession of the Vestertana Group contains two glaciogenic units, the Smalfjorden and Mortensnes formations, interpreted as end-Cryogenian Marinoan and Ediacaran glaciations, respectively. We investigated the OWM record in the Nyborg, Mortensnes, and St ' ahpogieddi formations to assess the impact of a glacial interval on the diversity of microscopic eukaryotes. A modified acid-extraction technique was applied to recover OWM from the diamictite matrix. The upper Nyborg Formation contains morphologically complex Doushantuo-Pertatataka acritarchs (DPA), restricting the age of the Nyborg Formation to early-mid Ediacaran. DPA occur below the dolostones that record a negative carbon isotope excursion correlated with the Shuram anomaly and below a glacial diamictite. A decline in species richness and compositional change is observed in the Mortensnes glacial assemblage. DPA are replaced by bacterial filaments and cell aggregates. The overlying Indreelva Member, St ' ahpogieddi Formation contains Ediacara-type biota and palaeopascichnids, but only a depauperate OWM assemblage of leiosphaerids and flask-shaped microfossils characteristic of the late Ediacaran.The succession of assemblages in the Vestertana Group demonstrates a turnover from large eukaryotic OWM to a microbial community in the glacial interval, to a low diversity post-glacial assemblage during the rise of macroscopic life. We compared the Vestertana record to global DPA occurrences. Although one DPA assemblage zone postdates the Shuram excursion, no DPA occur above Ediacaran glacial diamictites in successions where those deposits are present. Considering this, and the community changes in the Vestertana succession, we suggest that DPA were affected by the onset of an Ediacaran glaciation. Lastly, we combined the biostratigraphic markers in the Vestertana Group to constrain the age of the Mortensnes diamictite.
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| 3. |
- Cederstrom, Peter, et al.
(author)
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Morphology, ontogeny and distribution of the Cambrian Series 2 ellipsocephalid trilobite Strenuaeva spinosa from Scandinavia
- 2012
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In: GFF. - : Informa UK Limited. - 2000-0863 .- 1103-5897. ; 134:3, s. 157-171
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Journal article (peer-reviewed)abstract
- The ellipsocephalid trilobite Strenuaeva spinosa occurs widely in Scandinavia in the lower part of the Ornamentaspis? linnarssoni Zone (Cambrian Series 2). Its first appearance is a readily recognisable, widespread biohorizon in Scandinavia. During ontogeny, intergenal spines are lost and the librigenae develop from a generative zone in the genal region. The palpebro-ocular ridges are distinct and connected to the posterior part of the frontal glabellar lobe in the early meraspid period, but eye ridges become separate from the palpebral lobes and the glabella in the late meraspid period. S. spinosa is characterised by large genal spines, distinct axial spines and falcate pleural tips. The spines may have functioned in predation resistance. S. spinosa also has a small pointed projection at the anterolateral corners of some thoracic pleurae, the function of which is unknown. The presence of five furrows in the cephalic axial lobe of S. spinosa, best expressed in meraspides, suggests that the head of this ellipsocephalid trilobite was composed of six fused primary segments.
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| 4. |
- Ebbestad, Jan Ove R., 1967-, et al.
(author)
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Distribution and correlation of Sabellidites cambriensis (Annelida?) in the basal Cambrian on Baltica
- 2022
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In: Geological Magazine. - : Cambridge University Press. - 0016-7568 .- 1469-5081. ; 159:7, s. 1262-1283
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Journal article (peer-reviewed)abstract
- 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 Stahpogieddi 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.
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| 5. |
- Hoyberget, Magne, et al.
(author)
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The Skyberg Lagerstatte from the Mjosa area, Norway : a rare window into the late early Cambrian biodiversity of Scandinavia
- 2023
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In: Lethaia. - : Scandinavian University Press / Universitetsforlaget AS. - 0024-1164 .- 1502-3931. ; 56:2, s. 1-28
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Journal article (peer-reviewed)abstract
- The Skyberg Biota is a new early Cambrian Konservat-Lagerstatte, documented from a 7.5-m-thick succession of the Skyberg Member, Ringstranda Formation, in the classical Mjosa area of Norway. It displays a high species diversity and contains: algae; sponges; brachiopods; hyoliths; bivalved arthropods; trilobites; palaeoscolecids and other vermiform organisms; weakly sclerotized fragments of unknown affinity; several tubicolous fossils; the enigmatic genus Lapworthella; and a number of additional problematica together with infrequent trace fossils consisting of burrows and faecal pellets. This novel macro-biota encloses the most diverse fossil assemblage known from the Cambrian Series 2 locally in the Mjosa area, and regionally in Baltoscandia, and currently includes around 50 species of 10 major animal groups and macro-algae. The Skyberg Biota contains taxa previously unknown from Norway, several are new to Baltoscandia and also includes a range of new species. The Skyberg biota offers a rare glimpse into the biodiversity of Baltoscandia just prior to the large faunal turnover at the late-middle Cambrian transition.
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| 6. |
- Jensen, Soren, et al.
(author)
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New occurrences of Palaeopascichnus from the Stahpogieddi Formation, Arctic Norway, and their bearing on the age of the Varanger Ice Age
- 2018
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In: Canadian journal of earth sciences (Print). - : CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS. - 0008-4077 .- 1480-3313. ; 55:11, s. 1253-1261
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Journal article (peer-reviewed)abstract
- We report on new occurrences of the late Ediacaran problematicum Palaeopascichnus (Protista?) from the Stahpogieddi Formation, Arctic Norway. The stratigraphically lowest occurrences are in beds transitional between the Lillevannet and Indreelva members: the highest in the second cycle of the Manndrapselva Member, stratigraphically close to the lowest occurrences of Cambrian-type trace fossils. This establishes a long stratigraphical range of Palaeopascichnus on the Digermulen Peninsula, as has been previously documented from Newfoundland, South Australia, and elsewhere in Baltica. The age range of Palaeopascichnus in Avalonia and Baltica is from similar to 565 to 541 Ma. Since the transition from the Mortensnes Formation to the Stahpogieddi Formation is without a major break in sedimentation, this supports the inference that the underlying glacigenic Mortensnes Formation is ca. 580 Ma, and therefore Gaskiers-equivalent, or younger.
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| 7. |
- Jensen, Soren, et al.
(author)
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Scratch circles from the Ediacaran and Cambrian of Arctic Norway and southern Africa, with a review of scratch circle occurrences
- 2018
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In: Bulletin of Geosciences. - : CZECH GEOLOGICAL SURVEY. - 1214-1119 .- 1802-8225. ; 93:3, s. 287-304
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Research review (peer-reviewed)abstract
- Scratch circles - bedding plane parallel sedimentary structures formed by the passive rotation of a tethered organism into the surrounding sediment - are relatively rare in the geological record. Here new occurrences of scratch circles are described from the Ediacaran-Cambrian Stahpogieddi Formation, Digermulen Peninsula, Arctic Norway, and from the Ediacaran Nudaus and Urusis formations, Nama Group, of southern Africa. A literature survey confirms a previously noted concentration of scratch circles reported from shallow marine upper Ediacaran-lower Cambrian and paralic Carboniferous rocks. Scratch circle identification and nomenclature are discussed. The stratigraphical range of the trace fossils Treptichnus pedum and Gyrolithes isp. in the Stahpogieddi Formation are extended downward. Combined with earlier reports of Harlaniella podolica this adds new precision to the placement of the Ediacaran-Cambrian boundary on the Digermulen Peninsula.
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| 8. |
- Meinhold, Guido, et al.
(author)
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First record of carbonates with spherulites and cone-in-cone structures from the Precambrian of Arctic Norway, and their palaeoenvironmental significance
- 2019
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In: Precambrian Research. - : Elsevier BV. - 0301-9268 .- 1872-7433. ; 328, s. 99-110
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Journal article (peer-reviewed)abstract
- We report for the first time carbonates from the upper Ediacaran sedimentary succession of Finnmark, Arctic Norway. Carbonates occur as calcareous siliciclastic beds, lenses, and concretions, some with calcite spherulites and cone-in-cone (CIC) calcite, in a mudrock to fine-grained sandstone succession from approximately 3 m to 26 m above the base of the 2nd cycle of the Manndrapselva Member of the Stahpogieddi Formation (Vestertana Group). They occur c. 40 m below the Ediacaran-Cambrian boundary, which is well defined by trace fossils. Thin-section petrography and scanning micro X-ray fluorescence elemental mapping reveal a layered composition of the calcareous sedimentary rocks. In some of those, well-developed nested cones of CIC calcite form the outer layer. Thin clay coatings outline individual cones. The inner layers are composed of (1) carbonate with calcite spherulites (grainstone) and (2) thinly laminated fine-grained calcareous siliciclastics (mudstone and wackestone) indicated by elevated concentrations of Al, Si, Fe, and Ti. The inner siliciclastic layers contain framboidal pyrite and probably organic matter. Formation of calcite spherulites took place probably at the sediment-water interface either in a coastal littoral environment or in situ in the sublittoral zone under high alkaline conditions whereas CIC calcite formed during burial diagenesis and clearly in pre-Caledonian time before metamorphism and cleavage formation. This new record of carbonates with calcite spherulites and CIC structures from the Ediacaran of Arctic Norway adds to their rare occurrences in the geological record.
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| 9. |
- Meinhold, Guido, et al.
(author)
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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
- 2022
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In: Precambrian Research. - : Elsevier. - 0301-9268 .- 1872-7433. ; 381
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Journal article (peer-reviewed)abstract
- The Digermulen Peninsula in northeastern Finnmark, Arctic Norway, comprises one of the most complete Ediacaran-Cambrian transitions worldwide with a nearly continuous record of micro-and macrofossils from the interval of the diversification of complex life. Here, we report on the provenance and post-depositional alteration of argillaceous mudstones from the Digermulen Peninsula using rare earth elements and Sm-Nd and Rb-Sr isotopic systematics to provide an environmental context and better understand this important transition in Earth's history. The studied sections comprise a mid-Ediacaran glacial-interglacial cycle, including the Nyborg Formation (ca. 590 Ma) and Mortensnes Formation (related to the ca. 580 Ma-old Gaskiers glaciation), and the St & PRIME;ahpogieddi Formation (ca. 560-537 Ma), which yields Ediacara-type fossils in the Indreelva Member and contains the Ediacaran-Cambrian boundary interval in the Manndrapselva Member and basal part of the informal Lower Breidvika member (ca. 537-530 Ma). Three sample groups, (1) Nyborg and Mortensnes for-mations, (2) the lowermost five samples from the Indreelva Member and (3) the remaining samples from the Indreelva as well as from the Manndrapselva and Lower Breidvika members, can be distinguished, belonging to distinct depositional units. All samples have negative epsilon(Nd)(T) values (-6.00 to -21.04) indicating a dominant input of terrigenous detritus with an old continental crust affinity. Significant shifts in Sm-Nd isotope values are related to changes in the sediment source, i.e. Svecofennian province vs Karelian province vs Svecofennian province plus in addition likely some juvenile (late Neoproterozoic volcanic) material, and probably reflect palaeotectonic reorganisation along the Iapetus-facing margin of Baltica. The combined Rb-Sr isotopic data of all samples yield an errorchron age of about 430 Ma reflecting the resetting of the Rb-Sr whole-rock isotope systems of the mudstones during the Scandian tectono-metamorphic event in the Gaissa Nappe Complex of Finnmark. Preservation of palaeopascichnids coincides with the sedimentation regimes of sample groups 2 and 3 while other Ediacara-type fossils, e.g. Aspidella-type and frondose forms, are limited to the sample group 3. Our results are similar to those of earlier studies from the East European Platform in suggesting oxic seafloor conditions during the late Ediacaran.
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| 10. |
- Meinhold, Guido, et al.
(author)
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U-Pb dating of calcite in ancient carbonates for age estimates of syn- to post-depositional processes : a case study from the upper Ediacaran strata of Finnmark, Arctic Norway
- 2020
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In: Geological Magazine. - : CAMBRIDGE UNIV PRESS. - 0016-7568 .- 1469-5081. ; 157:8, s. 1367-1372
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Journal article (peer-reviewed)abstract
- 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.
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