Viser treff 316-335 av 711

    • Influence of a rigid backstop on the flow pattern during thrusting of the supracrustal Balsfjord Series of the North Norwegian Caledonides 

      Höpfl, Stephan Maximilian; Konopásek, Jiří; Sláma, Jiří (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-17)
      The Caledonian evolution of the low–medium grade Balsfjord Series (Troms, Northern Norway) is characterized by four sets of deformation structures that developed progressively during burial and exhumation from underneath the high-grade Nakkedal and Tromsø nappe complexes. The Balsfjord Series commonly displays top-to-the SSE–SE directed movement during the development of the main metamorphic fabric ...
    • The influence of Coriolis force driven water circulation on the palaeoenvironment of Hornsund (S Spitsbergen) over the last century 

      Pawłowska, Joanna; Zajączkowski, Marek; Szczuciński, Witold; Zaborska, Agata; Kucharska, Małgorzata; Jernas, Patrycja Ewa; Forwick, Matthias (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-22)
      The influence of the Coriolis force on the Hornsund fjord environment (southern Spitsbergen) was investigated in the marine sedimentary record from the last century. Due to the influence of the rotational effects, Atlantic and Arctic Water enter the fjord along the southern shore and exit along the northern shore. Thus, the sedimentary record from the southern part reflects the large‐scale hydrological ...
    • Influence of methane seepage on isotopic signatures in living deep-sea benthic foraminifera, 79° N 

      Melaniuk, Katarzyna; Sztybor, Kamila; Treude, Tina; Sommer, Stefan; Rasmussen, Tine Lander (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-21)
      Fossil benthic foraminifera are used to trace past methane release linked to climate change. However, it is still debated whether isotopic signatures of living foraminifera from methane-charged sediments refect incorporation of methane-derived carbon. A deeper understanding of isotopic signatures of living benthic foraminifera from methane-rich environments will help to improve reconstructions of ...
    • The inheritance of a Mesozoic landscape in western Scandinavia 

      Fredin, Ola; Viola, Giulio; Zwingmann, Horst; Sørlie, Ronald; Brönner, Marco; Lie, Jan-Erik; Grandal, Else Margrethe; Müller, Axel Bernd; Margreth, Annina; Vogt, Christoph; Knies, Jochen (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-28)
      In-situ weathered bedrock, saprolite, is locally found in Scandinavia, where it is commonly thought to represent pre-Pleistocene weathering possibly associated with landscape formation. The age of weathering, however, remains loosely constrained, which has an impact on existing geological and landscape evolution models and morphotectonic correlations. Here we provide new geochronological evidence ...
    • Innovative methods to monitor rock and mountain slope deformation 

      Hormes, Anne; Adams, Marc; Amabile, Anna Sara; Blauensteiner, Franz; Demmler, Christian; Fey, Christine; Ostermann, Marc; Rechberger, Christina; Sausgruber, Thomas; Vecchiotti, Filippo; Vick, Louise Mary; Zangerl, Christian (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-17)
      Displacement rates of mountain slope deformations that can affect entire valley mountain flanks are often measured spatially distributed in‐situ without spatial significance. The spatially explicit measurement and recording of time series of slope deformations is a challenge, as the unstable slopes are often disintegrated into several subdomains, which move with different deformation rates. The ...
    • Insights into the REY inventory of seep carbonates from the Northern Norwegian margin using geochemical screening 

      Schier, Katharina; Himmler, Tobias; Lepland, Aivo; Kraemer, Dennis; Schönenberger, Jasmin; Bau, Michael (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-27)
      Rare earth element and yttrium (REY) systematics of authigenic seep carbonates can provide insights into the physico-chemical characteristics of seep systems and allow discrimination of carbonate precipitation under seawater- or porewater-dominated fluid regimes. However, care must be taken when interpreting their REY systematics, since seep carbonates comprise a mixture of detrital silicates and ...
    • An integrated view of the methane system in the pockmarks at Vestnesa Ridge, 79°N 

      Panieri, Giuliana; Bünz, Stefan; Fornari, Daniel J.; Escartin, Javier; Serov, Pavel; Jansson, Pär; Torres, Marta E.; Hong, Wei-Li; Sauer, Simone; Garcia, Rafael; Gracias, Nuno (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-08)
      The Vestnesa Ridge is a NW-SE trending, ~ 100 km-long, 1–2 km-thick contourite sediment section located in the Arctic Ocean, west of Svalbard, at 79°N. Pockmarks align along the ridge summit at water depths of ~ 1200 m; they are ~ 700 m in diameter and ~ 10 m deep relative to the surrounding seafloor. Observations of methane seepage in this area have been reported since 2008. Here we summarize and ...
    • An Integrative Taxonomic Survey of Benthic Foraminiferal Species (Protista, Rhizaria) from the Eastern Clarion-Clipperton Zone 

      Himmighofen, Oceanne E.; Holzmann, Maria; Barrenechea Angeles, Inés; Pawlowski, Jan; Gooday, Andrew J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-24)
      The abyssal Pacific Clarion Clipperton Zone (CCZ) hosts vast, commercially valuable seafloor deposits of polymetallic nodules. Foraminifera (testate protists) dominate benthic communities in this region. Here, we present a taxonomic survey, combining morphological and genetic data and focussing on mainly meiofauna-sized Foraminifera from the eastern CCZ. Sequences obtained from >100 specimens, the ...
    • Interactions between deep formation fluid and gas hydrate dynamics inferred from pore fluid geochemistry at active pockmarks of the Vestnesa Ridge, west Svalbard margin 

      Hong, Wei-Li; Pape, T; Schmidt, C.; Yao, Haoyi; Wallmann, K.; Plaza-Faverola, Andreia; Rae, J.W.B; Lepland, Aivo; Bünz, Stefan; Bohrmann, G. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-11)
      Seafloor seepage sites along the Vestnesa Ridge off west-Svalbard have been, for decades, a natural laboratory for the studies of fluid flow and gas hydrate dynamics at passive continental margins. The lack of ground truth evidence for fluid composition and gas hydrate abundance deep in the sediment sequence however prohibits us from further assessing the current model of pockmark evolution from the ...
    • Introduction to the volume, and definition and use of the term ‘tectono-sedimentary element’ 

      Drachev, Sergey; Brekke, Harald; Henriksen, Erik; Moore, Thomas (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-20)
      The present volume is rooted in a map of sedimentary successions of the Arctic Region by Grantz et al. (2011), and contains a brief, but comprehensive compilation of geological and geophysical data characterizing all significant sedimentary successions in the Arctic, which cover 57% of the polar area north of 64°N. Two main goals have been designated: (i) to provide, based on the present-day ...
    • Introduction: Processes and Palaeo-Environmental Changes in the Arctic from Past to Present (PalaeoArc) special issue 

      Lyså, Astrid; Jennings, Anne; Morigi, Caterina; Stokes, Chris R.; Winsborrow, Monica (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-05)
      PalaeoArc (Processes and Palaeo-Environmental Changes in the Arctic: From Past to Present) is an international network research programme, the aim of which is to understand and explain the climatically induced environmental changes in the Arctic that have taken place throughout the Quaternary and continue in the present-day (see http://www.palaeoarc.no/). This network builds on and extends the ...
    • Ionospheric Response Observed by EISCAT During the 6–8 September 2017 Space Weather Event: Overview 

      Yamauchi, M; Sergiengko, Timothy; Enell, Carl-Fredrik; Schillings, A.; Slapak, R.; Johnsen, Magnar Gullikstad; Tjulin, A.; Nilsson, H. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-03)
      We present ionospheric plasma conditions observed by the EISCAT radars in Tromsø and on Svalbard, covering 68°–81° geomagnetic latitude, during 6–8 September 2017. This is a period when X2.2 and X9.3 X‐ray flares occurred, two interplanetary coronal mass ejections (ICMEs) arrived at the Earth accompanied by enhancements of MeV‐range energetic particle flux in both the solar wind (SEP event) and inner ...
    • Iron cycling in Arctic methane seeps 

      Hong, Wei-Li; Latour, Pauline; Sauer, Simone; Sen, Arunima; Gilhooly, William P.; Lepland, Aivo; Fouskas, Fotios (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-26)
      Anoxic marine sediments contribute a significant amount of dissolved iron (Fe<sup>2+</sup>) to the ocean which is crucial for the global carbon cycle. Here, we investigate iron cycling in four Arctic cold seeps where sediments are anoxic and sulfidic due to the high rates of methane-fueled sulfate reduction. We estimated Fe<sup>2+</sup> diffusive fluxes towards the oxic sediment layer to be in the ...
    • Iron isotopes constrain sub-seafloor hydrothermal processes at the Trans-Atlantic Geotraverse (TAG) active sulfide mound 

      Sahlström, Fredrik; Troll, Valentin R; Strmic Palinkas, Sabina; Kooijman, Ellen; Zheng, Xinyuan (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-29)
      Sub-seafloor hydrothermal processes along volcanically active plate boundaries are integral to the formation of seafloor massive sulfide deposits and to oceanic iron cycling, yet the nature of their relationship is poorly understood. Here we apply iron isotope analysis to sulfide minerals from the Trans-Atlantic Geotraverse (TAG) mound and underlying stockwork, 26°N Mid-Atlantic Ridge, to trace ...
    • Is there a Climatic Control on Icelandic Volcanism? 

      Cooper, Claire L.; Savov, Ivan P.; Patton, Henry; Hubbard, Alun; Ivanovic, Ruza F.; Carrivick, Jonathan L.; Swindles, Graeme T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-07)
      The evidence for periods of increased volcanic activity following deglaciation, such as following ice sheet retreat after the Last Glacial Maximum, has been examined in several formerly glaciated areas, including Iceland, Alaska, and the Andean Southern Volcanic Zone. Here we present new evidence supporting the theory that during episodes of cooling in the Holocene, Icelandic volcanic activity ...
    • K-Ar illite and apatite fission track constraints onbrittle faulting and the evolution of the northern Norwegian passive margin 

      Davids, Corine; Wemmer, Klaus; Zwingmann, Horst; Kohlmann, Fabian; Jacobs, Joachim; Bergh, Steffen G (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Determining the timing of post-Caledonian brittle faulting in northern Norway is important for the understanding of the extensional tectonic evolution of the north Norwegian continental margin. Fault gouges from the Troms and Vesterålen regions of northern Norway yield Carboniferous to Permian and Carboniferous to Cretaceous K–Ar illite ages, respectively. The results show a contrast in fault activity ...
    • Keystone Arctic paleoceanographic proxy association with putative methanotrophic bacteria 

      Bernhard, Joan M.; Panieri, Giuliana (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-13)
      Foraminifera in sediments exposed to gas-hydrate dissociation are not expected to have cellular adaptations that facilitate inhabitation of chemosynthesis-based ecosystems because, to date, there are no known endemic seep foraminifera. To establish if foraminifera inhabit sediments impacted by gas-hydrate dissociation, we examined the cellular ultrastructure of <i>Melonis barleeanus</i> (Williamson, ...
    • Labilibaculum manganireducens gen. nov., sp. nov. and Labilibaculum filiforme sp. nov., Novel Bacteroidetes Isolated from Subsurface Sediments of the Baltic Sea 

      Vandieken, Verona; Marshall, Ian P.G.; Niemann, Helge; Engelen, Bert; Cypionka, Heribert (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-05)
      Microbial communities in deep subsurface sediments are challenged by the decrease in amount and quality of organic substrates with depth. In sediments of the Baltic Sea, they might additionally have to cope with an increase in salinity from ions that have diffused downward from the overlying water during the last 9000 years. Here, we report the isolation and characterization of four novel bacteria ...
    • Lake Sedimentary DNA Research on Past Terrestrial and Aquatic Biodiversity: Overview and Recommendations 

      Capo, Eric; Giguet-Covex, Charline; Rouillard, Alexandra; Nota, Kevin; Heintzman, Peter D.; Vuillemin, Aurèle; Ariztegui, Daniel; Arnaud, Fabien; Belle, Simon; Bertilsson, Stefan; Bigler, Christian; Bindler, Richard; Brown, Antony G.; Clarke, Charlotte L.; Crump, Sarah E.; Debroas, Didier; Englund, Göran; Ficetola, Gentile Francesco; Garner, Rebecca E.; Gauthier, Joanna; Gregory-Eaves, Irene; Heinecke, Liv; Herzschuh, Ulrike; Ibrahim, Anan; Kisand, Veljo; Kjær, Kurt H.; Lammers, Youri; Littlefair, Joanne; Messager, Erwan; Monchamp, Marie-Eve; Olajos, Fredrik; Orsi, William; Pedersen, Mikkel W.; Rijal, Dilli P.; Rydberg, Johan; Spanbauer, Trisha; Stoof-Leichsenring, Kathleen R.; Taberlet, Pierre; Talas, Liisi; Thomas, Camille; Walsh, David A.; Wang, Yucheng; Willerslev, Eske; van Woerkom, Anne; Zimmermann, Heike H.; Coolen, Marco J. L.; Epp, Laura S.; Domaizon, Isabelle; Alsos, Inger G.; Parducci, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-13)
      The use of lake sedimentary DNA to track the long-term changes in both terrestrial and aquatic biota is a rapidly advancing field in paleoecological research. Although largely applied nowadays, knowledge gaps remain in this field and there is therefore still research to be conducted to ensure the reliability of the sedimentary DNA signal. Building on the most recent literature and seven original ...
    • Large subglacial meltwater features in the central Barents Sea 

      Bjarnadóttir, Lilja Rún; Winsborrow, Monica; Andreassen, Karin (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-01)
      During the last glacial period large parts of the Arctic, including the Barents Sea, north of Norway and Russia, were covered by ice sheets. Despite several studies indicating that melting occurred beneath much of the Barents Sea ice sheet, very few meltwater-related landforms have been identified. We document ∼200 seafloor valleys in the central Barents Sea and interpret them to be tunnel valleys ...