Cambrian (Series 3 – Furongian) conodonts from the Alum Shale Formation at Slemmestad, Oslo Region, Norway

Nine samples from the Alum Shale of Slemmestad, Oslo Region, were processed for conodonts. The limestone-rich interval extending from the mid Cambrian Paradoxides paradoxissimus trilobite Zone to the Lower Ordovician Boeckaspis trilobite Zone yielded a sparse conodont fauna. The fauna is dominated by the protoconodont species Phakelodus elongatus (Zhang in An et al., 1983) and Phakelodus tenuis Müller, 1959, the paraconodont species Westergaardodina polymorpha Müller & Hinz, 1991, Westergaardodina ligula Müller & Hinz, 1991, Problematoconites perforatus Müller, 1959 and Trolmenia acies Müller & Hinz, 1991; the euconodont species Cordylodus proavus Müller, 1959 is present in the Acerocarina Superzone. The presence of the cosmopolitan Cordylodus proavus Müller, 1956 at Slemmestad provides an important tie for regional and international correlation.publishedVersio

Scale dependent diversity of bryozoan assemblages in the reefs of the Late Ordovician Vasalemma Formation, Estonia

The fieldwork for BK and AP was partly funded by the Academy of Finland project ‘Ecological Engineering as a Biodiversity Driver in Deep Time’ (Decision No. 309422). Deutsche Forschungsgemeinschaft (DFG) is appreciated for financial support of AE (project ER 278/10.1). The work is a contribution to the IGCP program 735 ‘Rocks and the Rise of Ordovician Life’.The reefs of the Vasalemma Formation, late Sandbian, Late Ordovician, of northern Estonia contain an exceptional rich and abundant bryozoan fauna. They are an example of contemporaneous bryozoan-rich reefs known from around the world, representing the peak diversification interval of this group during the Ordovician. The global Ordovician bryozoan diversification was associated with a decrease in provinciality, a pattern known from other skeletal marine metazoans of this period. The diversification is associated with climatic cooling and increasing atmospheric and sea water oxygenation. However, the mechanisms that led to the bryozoan diversification are poorly known. Here we estimate the bryozoan richness (α and γ diversity) and turnover (β diversity) at the level of samples, reefs, and formations in the Vasalemma Formation and in contemporaneous reef limestone occurrences of the Baltoscandian region. The resulting richness and turnover values differ among the three observational levels and hence are scale dependent. A consistent pattern with lowest between-reef turnover and relatively high between-sample turnover could be detected, reflecting high small-scale (within reef) heterogeneities in lithology and original bryozoan habitat. This is consistent with published work, in which evidence has been presented for small-scale substrate heterogeneity as the most important diversification driver of the Ordovician brachiopod diversification in the Baltoscandian region. The fact that reefs and their local substrate are strongly organism moderated environments sheds light on the potentially important ecosystem engineering role of organisms, such as bryozoans, for the Ordovician diversification.Publisher PDFPeer reviewe

A Cambrian–Ordovician boundary section in the Rafnes–Herøya submarine tunnel, Skien–Langesund District, southern Norway

Rock specimens and contained fossils collected in 1976 from a submarine tunnel driven between Herøya and Rafnes in the Skien–Langesund area of southern Norway, have been restudied. The contained fossils include olenid and agnostoid trilobites, graptolites and brachiopods, groups described in detail for the first time from the area and documenting a Cambrian–Ordovician boundary section unique in the district where the upper Cambrian Alum Shale Formation is elsewhere overlain by the Middle Ordovician Rognstranda Member of the Huk Formation (Kundan in terms of Baltoscandian chronostratigraphy). The hiatus at the base of the Huk Formation is thus smaller in the section described herein, beginning at a level within rather than below the Tremadocian. Estimated thickness of the Alum Shale includes 10–12 m of Miaolingian and 20–22 m of Furongian strata with trilobite zones identified, and a Tremadocian section of 8.1 m identified by species of the dendroid graptolite Rhabdinopora in the basal 2.6 m and Bryograptus ramosus at the top. The Tremadocian section is preserved in a postulated zone of synsedimentary subsidence along the Porsgrunn–Kristiansand Fault Zone, while at the same time there was extensive erosion across an emergent, level platform elsewhere in the Skien–Langesund District and the southern part of the Eiker–Sandsvær District to the north. Aspects of stratigraphy and tectonics are highlighted together with a discussion on the Cambrian– Ordovician boundary locally and worldwide

Diversity and spatial turnover of bryozoan assemblages in the reefs of the Vasalemma Formation (Late Ordovician), Estonia

The reefs of the Vasalemma Formation, late Sandbian, Late Ordovician, of northern Estonia contain an exceptionally rich and abundant bryozoan fauna. They are an example of contemporaneous bryozoan-rich reefs known from around the world, representing the peak diversification interval of this group during the Ordovician. The diversification is associated with global climatic cooling and increasing atmospheric and sea water oxygenation. However, the mechanisms that led to the bryozoan diversification are poorly known. Here we estimate the bryozoan richness (α and γ diversity) and turnover (β diversity) at the level of samples, reefs, and formations in the Vasalemma Formation. The resulting richness and turnover values differ among the three observational levels and hence are scale dependent. A pattern with lowest between-reef turnover and relatively high between-sample turnover could be detected, reflecting high small-scale (within reef) heterogeneities in lithology and original bryozoan habitat. This is consistent with the hypothesis that small-scale substrate heterogeneity was the most important diversification driver in the Vasalemma Formation

Late Jurassic–Early Cretaceous hydrocarbon seep boulders from Novaya Zemlya and their faunas

The paper describes Late Jurassic–Early Cretaceous seep carbonate boulders from the Russian Arctic island of Novaya Zemlya, collected in 1875 by A.E. Nordenskiöld during his expedition to Siberia. The carbonates are significantly depleted in heavy carbon isotopes (δ13C values as low as ca. − 40‰) and show textures typical for carbonates formed under the influence of hydrocarbons, such as fibrous carbonate cements and corrosion cavities. The rocks contain index fossils of Late Oxfordian–Early Kimmeridgian, Late Tithonian (Jurassic) and latest Berriasian–Early Valanginian (Cretaceous) age. The fossil fauna is species rich and dominated by molluscs, with subordinate brachiopods, echinoderms, foraminifera, serpulids and ostracods. Most of the species, including two chemosymbiotic bivalve species, likely belong to the ‘background’ fauna. Only a species of a hokkaidoconchid gastropod, and a possible abyssochrysoid gastropod, can be interpreted as restricted to the seep environment. Other seep faunas with similar taxonomic structure are suggestive of rather shallow water settings, but in case of Novaya Zemlya seep faunas such structure might result also from high northern latitude

Paleocene methane seep and wood-fall marine environments from Spitsbergen, Svalbard

A recently discovered Paleocene seep locality from Fossildalen on Spitsbergen, Svalbard, is described. This is one of a very few seep communities of the latest Cretaceous–earliest Palaeogene age, and the best preserved Paleocene seep community known so far. The seep carbonates and associated fossils have been first identified in museum collections, and subsequently sampled in the field. The carbonates are exclusively ex-situ and come from the offshore siltstones of the Basilika Formation. Isotopically light composition (δ13C values approaching -50‰ V-PDB), and characteristic petrographic textures of the carbonates combined with the isotopically light archaeal lipid are consistent with the formation at fossil hydrocarbon seep. The invertebrate fauna associated with the carbonates is of moderate diversity (16 species) and has a shallow water affinity. It contains a species of the thyasirid genus Conchocele, common in other seeps of that age. The finding sheds new light onto the history of seepage on Svalbard, and onto the evolution and ecology of seep faunas during the latest Cretaceous–earliest Palaeogene time interval

FIGURE 9 in Gastropods from the Late Jurassic - Early Cretaceous seep deposits in Spitsbergen, Svalbard

FIGURE 9. Hyalogyrina knorringfjelletensis sp. nov. Sassenfjorden, Svalbard; late Berriasian (Early Cretaceous). A, F. PMO 217.508, Seep deposit #12. B, H, I. Paratype (PMO 217.510), Seep deposit #12. C, D, E, J. Holotype (PMO 217.511a), Seep deposit #12. G. Juvenile (PMO 224.763), Seep deposit #9

Innspill til forvaltningsplan for Steinvika og Langesundstangen naturreservater i Telemark - Geologi

Erikstad, L. og Nakrem, H.A. 2016. Innspill til forvaltningsplan for Steinvika og Langesundstangen naturreservater i Telemark – Geologi - NINA Rapport 1281. 45 s. De to naturreservatene Steinvika og Langesundstangen ligger i Bamble kommune i Telemark fylke. De ligger i et område med kalkrike bergarter helt vest i den geologiske provinsen som kalles Oslofeltet. Bergartene er fra den geologiske perioden ordovicium og det er definert fire separate enheter knyttet til dem innen området: Fossumformasjonen, Steinvikformasjonen, Venstøpformasjonen og Herøyformasjonen. Bergartene er fossilrike og områdene fremviser et rikt geologisk mangfold knyttet til fossilene og bergartene og deres strukturer. Landformene er sterkt preget av bergartslagenes helning mot øst-nordøst, noe som gir stup og skrenter i den vestlige delen av området og roligere terreng i øst. Breenes erosjon og modifisering av disse bergrunnsgeologiske bestemte terrengformene er tydelig innen området. Området har store biologiske verdier og forvaltningen må så langt som råd ta vare både på geologiske og biologiske verdier uten at tiltakene kommer i konflikt med hverandre. Grovt sett kan man si at kystområdene med strandberg og bart berg sammen med stup og skrenter er de viktigste geologiske verdiene, mens skogområdene og grunnlendt mark er de viktigste biologisk. Bart fjell inneholder en del sjeldne skorpelav som kan forstyrre dette bilde noe, men de fleste stedene er denne lavveksten ikke så omfattende at de forstyrrer mulighetene til å se, studere og oppleve geologien. Noen steder er det påvist behov for å rydde i vegetasjonen. Her er det mange steder et innslag av fremmede arter slik at det er et visst sammenfall i forvaltningsønskene fra de ulike fagfeltene. Det er stor ferdsel i området og noen steder er det påvist en del slitasje, men uten at dette går ut over de geologiske verdiene. Tilrettelegging av ferdsel og for bading kan komme i konflikt med de geologiske verdiene og det er viktig at man i slike saker utøver stor forsiktighet og benytter geologisk ekspertise. Bruk av åpen ild er forbudt og åpen ild inkludert engangsgriller er en trussel mot fine strukturer og fossiler i berggrunnen. Det bør vurderes om det er mulig å etablere faste grillplasser i området og samtidig øke informasjonen om hvorfor engangsgriller og bål på fjell-grunn er et problem. Området er en del av Gea Norvegica Geopark og det er satt opp informasjonsskilt i området. Skiltingen utenfor disse geoparkskiltene kan imidlertid forbedres noe.Erikstad, L. and Nakrem, H.A. 2016. Geological input to a management plan for the nature reserves Steinvika and Langesundstangen in Telemark County. - NINA Rapport 1281. 45 s. The two nature reserves Steinvika and Langesundtangen are situated in Bamble municipality in the county of Telemark. They belong the geological province Oslofeltet (the Oslo area) and have a dominance of Ordovician limestone. Four different formations are defined within the area: The Fossum formation, the Steinvika formation, the Venstøp formation and the Herøya formation. The limestone is rich in fossils and the area have a large geodiversity linked to its fossils, the rocks and the bedrock structures. The landforms are strongly influenced by the structure of the bedrock with a dip towards east-northeast. This results in cliffs and steep terrain in the western part of the area and calmer terrain in the eastern part. The influence of the last glaciation is also clearly visible. The area has also high biological value and the management must pay close attention to both to biodiversity and geodiversity values (geoheritage) and build strategies to avoid conflict be-tween the two. A general classification of the terrain that define where geological and biological values dominate can serve as a guideline. Geology has its main values in rock outcrops along the shoreline and in cliffs, while the forested area and the areas with shallow vegetation-covered soils have highest biological value. On the bedrock outcrops it is, however, identified some rare crustaceous lichen species who can represent a management challenge, but on most places the occurrence of lichens is not so extensive that they disturb the possibility to see, study and expe-rience the geology. Some places have the need of clearing of vegetation. These are starting to be overgrown with bushes and some trees. Several places have a distinct element of alien invasive species which also represent a threat to the biological values. Therefore, it is a common management need to stop this type of overgrowing of the area. The area is much used for recreation and a degree of threat from wear and tear is documented a couple of places. The need for measures to facilitate paths, bathing platforms etc. may be in conflict with the geological values and it is important that the management show great care about such activities and consult geologists if in doubt. Use of open fire is not allowed in the area and the use of open fires and disposable grills is a threat to fossils and fine bedrock structures. Measures like building more permanent grills should be assessed together with increased infor-mation of the rationale for banning open fire in the area. The area is a part of the Gea Norvegica Geopark and information signs is established in few selected places. Signposting outside these localities may however bee improved.© Norsk institutt for naturforskning. Publikasjonen kan siteres fritt med kildeangivelse