Now showing items 183-202 of 315

    • Natural variability of benthic foraminiferal assemblages and metal concentrations during the last 150 years in the Ingøydjupet trough, SW Barents Sea. 

      Dijkstra, Noortje; Junttila, Juho; Husum, Katrine; Carroll, JoLynn; Hald, Morten (Journal article; Tidsskriftartikkel, 2015-12)
      While today the SW Barents Sea is a relatively un-impacted and uncontaminated area, industrial activities related to the petroleum industry are projected to increase in the coming decades. This makes the area a valuable natural laboratory to establish pre-impacted baselines as a precursor for future seabed monitoring programs. Here we present benthic foraminiferal assemblages and metal concentrations ...
    • Neogene dinoflagellate cysts and acritarchs from the high northern latitudes and their relation to sea surface temperature 

      Schreck, Michael; Nam, Seung-Il; Clotten, Caroline; Fahl, Kirsten; De Schepper, Stijn; Forwick, Matthias; Matthiessen, Jens (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-13)
      <p>Organic-walled dinoflagellate cysts and acritarchs are a vital tool for reconstructing past environmental change, in particular in the Neogene of the high northern latitudes where marine deposits are virtually barren of traditionally used calcareous microfossils. Yet only little is known about the paleoenvironmental value of fossil assemblages that do not have modern analogues, so that reconstructions ...
    • Neoproterozoic and post-Caledonian exhumation and shallow faulting in NW Finnmark from K–Ar dating and p/T analysis of fault rocks 

      Koehl, Jean-Baptiste P.; Bergh, Steffen G; Wemmer, Klaus (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-20)
      Well-preserved fault gouge along brittle faults in Paleoproterozoic, volcano-sedimentary rocks of the Raipas Supergroup exposed in the Alta–Kvænangen tectonic window in northern Norway yielded latest Mesoproterozoic (approximately 1050 15 Ma) to mid-Neoproterozoic (approximately 825–810 18 Ma) K–Ar ages. Pressure–temperature estimates from microtextural and mineralogy analyses of fault ...
    • A new genus and two new species of Thyasiridae associated with methane seeps off Svalbard, Arctic Ocean 

      Åström, Emmelie; Oliver, Graham; Carroll, Michael Leslie (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-05-16)
      Bivalves have been found in unique benthic assemblages associated with active methane seeps and mounds along the western and southern margins of the Svalbard shelf (75–79°N) at 350–380 m depth. Among the samples collected were a number of shells of Thyasiridae that are distinct from any species previously described. Here we describe one new genus Rhacothyas gen. nov. and two new species Thyasira ...
    • New geophysical evidence for a revised maximum position of part of the NE sector of the Greenland ice sheet during the last glacial maximum 

      Laberg, Jan Sverre; Forwick, Matthias; Husum, Katrine; Laberg, Jan Sverre (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-26)
      The extent and dynamics of the north-eastern sector of the Greenland ice sheet (GIS) during the last glacial still remain very uncertain, and maximum ice extents to inner-shelf, mid-shelf and outer-shelf positions have been suggested. Here we argue that the margin of the GIS reached the shelf break along part of its NE sector during the last glacial maximum. Swath-bathymetry and sub-bottom profiler ...
    • A new numerical model for understanding free and dissolved gasprogression toward the atmosphere in aquatic methane seepage systems 

      Jansson, Pär; Ferré, Benedicte; Silyakova, Anna; Dølven, Knut Ola; Omstedt, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-16)
      We present a marine two‐phase gas model in one dimension (M2PG1) resolving interaction between the free and dissolved gas phases and the gas propagation toward the atmosphere in aquatic environments. The motivation for the model development was to improve the understanding of benthic methane seepage impact on aquatic environments and its effect on atmospheric greenhouse gas composition. Rising, ...
    • Nordic Seas polynyas and their role in preconditioning marine productivity during the Last Glacial Maximum 

      Knies, Jochen; Koseoglu, Denizcan; Rise, Leif; Baeten, Nicole; Bellec, Valerie K; Bøe, Reidulv; Klug, Martin; Panieri, Giuliana; Jernas, Patrycja Ewa; Belt, Simon T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-27)
      Arctic and Antarctic polynyas are crucial sites for deep-water formation, which helps sustain global ocean circulation. During glacial times, the occurrence of polynyas proximal to expansive ice sheets in both hemispheres has been proposed to explain limited ocean ventilation and a habitat requirement for marine and higher-trophic terrestrial fauna. Nonetheless, their existence remains equivocal, ...
    • Norges grenser i dyphavet 

      Vorren, Tore Ola; Laberg, Jan Sverre (Chronicle; Kronikk, 2010-08-14)
    • A North Atlantic tephrostratigraphical framework for 130–60 ka b2k: new tephra discoveries, marine-based correlations, and future challenges 

      Davies, Siwan M.; Abbott, Peter M.; Meara., Rhian H.; Pearce, Nicholas J.G.; Austin, William E.N.; Chapman, Mark R.; Svensson, Anders; Bigler, Matthias; Rasmussen, Tine Lander; Rasmussen, Sune O.; Farmer, Elisabeth J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • North Atlantic warming during Dansgaard-Oeschger events synchronous with Antarctic warming and out-of-phase with Greenland climate 

      Rasmussen, Tine Lander; Thomsen, Erik; Moros, Matthias (Journal article; Peer reviewed; Tidsskriftartikkel, 2016-02-05)
      The precise reason for the differences and out-of-phase relationship between the abrupt Dansgaard- Oeschger warmings in the Nordic seas and Greenland ice cores and the gradual warmings in the southcentral Atlantic and Antarctic ice cores is poorly understood. Termed the bipolar seesaw, the differences are apparently linked to perturbations in the ocean circulation pattern. Here we show that ...
    • Northward advection of Atlantic water in the eastern Nordic Seas over the last 3000 yr 

      Dylmer, C. V.; Giraudeau, Jacques; Eynaud, F; Husum, Katrine; de Vernal, A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Three marine sediment cores distributed along the Norwegian (MD95-2011), Barents Sea (JM09-KA11-GC), and Svalbard (HH11-134-BC) continental margins have been investigated in order to reconstruct changes in the poleward flow of Atlantic waters (AW) and in the nature of upper surface water masses within the eastern Nordic Seas over the last 3000 yr. These reconstructions are based on a limited set ...
    • Norwegian margin outer shelf cracking: a consequence of climate-induced gas hydrate dissociation? 

      Vanneste, Maarten; Mienert, Jurgen; Haflidason, H; Bünz, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2010)
    • A novel biomarker-based proxy for the spring phytoplankton bloom in Arctic and sub-arctic settings – HBI T25 

      Belt, Simon T.; Smik, Lukas; Köseoğlu, Denizcan; Knies, Jochen; Husum, Katrine (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-19)
      The spring phytoplankton bloom is a characteristic feature of mid-high latitudes in modern times, but can be challenging to identify in palaeo records. In the current study, we investigated the absolute and relative distributions of two diatom-derived tri-unsaturated highly branched isoprenoid (HBI) lipids, at least one of which has previously been suggested to be a possible proxy for the productive ...
    • Novel biomineralization strategy in calcareous foraminifera 

      Borrelli, Chiara; Panieri, Giuliana; Dahl, Trine Merete; Neufeld, Kai (Journal article; Tidsskriftartikkel; Peer reviewed, 2018)
      This work shows that calcareous benthic foraminifera are capable of agglutinating sedimentary particles also. In particular, we focus on Melonis barleeanus. Traditionally considered a calcareous species, our data revealed the presence of minute (~3 μm) sedimentary particles (silicate grains) inside the chamber walls of the examined shells. These particles were arranged in a definitive and systematic ...
    • OBS Data Analysis to Quantify Gas Hydrate and Free Gas in the South Shetland Margin (Antarctica) 

      Song, Sha; Tinivella, Umberta; Giustiniani, Michela; Singhroha, Sunny; Bünz, Stefan; Cassiani, Giorgio (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-25)
      The presence of a gas hydrate reservoir and free gas layer along the South Shetland margin (offshore Antarctic Peninsula) has been well documented in recent years. In order to better characterize gas hydrate reservoirs, with a particular focus on the quantification of gas hydrate and free gas and the petrophysical properties of the subsurface, we performed travel time inversion of ocean-bottom ...
    • Ocean temperature variability for the past 60 years on the Norwegian-Svalbard margin influences gas hydrate stability on human time scales 

      Ferré, Benedicte; Mienert, Jurgen; Feseker, Tomas (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-10-23)
      The potential impact of future climate change on methane release from oceanic gas hydrates is the subject of much debate. We analyzed World Ocean Database quality controlled data on the Norwegian‐Svalbard continental margin from the past 60 years to evaluate the potential effect of ocean temperature variations on continental margin gas hydrate reservoirs. Bottom water temperatures in the Norwegian‐Svalbard ...
    • On Palaeozoic-Mesozoic brittle normal faults along the SW Barents Sea margin: fault processes and implications for basement permeability and margin evolution 

      Indrevær, Kjetil; Stunitz, Holger; Bergh, Steffen G (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • On the causes of Arctic sea ice in the warm Early Pliocene 

      Clotten, Caroline; Stein, Rüdiger; Fahl, Kirsten; Schreck, Michael; Risebrobakken, Bjørg; De Schepper, Stijn (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-30)
      Scattered and indirect evidence suggests that sea ice occurred as far south as the Iceland Sea during the Early Pliocene, when the global climate was warmer than present. However, conclusive evidence as well as potential mechanisms governing sea ice occurrence outside the Arctic Ocean during a time with elevated greenhouse gas concentrations are still elusive. Here we present a suite of organic ...
    • The onset of flysch sedimentation in the Kaoko Belt (NW Namibia) – Implications for the pre-collisional evolution of the Kaoko–Dom Feliciano–Gariep orogen 

      Konopásek, Jiří; Hoffmann, Karl Heinz; Sláma, Jiří; Košler, Jan (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-17)
      <p>Detrital zircon provenance study of a metamorphosed sedimentary succession in the eastern part of the Kaoko Belt in Namibia has revealed two distinct sources for the Neoproterozoic sedimentation along the southwestern Congo Craton margin. The lower part of the succession shows detrital zircon ages consistent with erosion of Paleoproterozoic basement of the Congo Craton with an inferred Mesoproterozoic ...
    • Optimising the use of marine tephrochronology in the North Atlantic: a detailed investigation of the Faroe Marine Ash Zones II, III and IV 

      Griggs, Adam J.; Davies, Siwan M.; Abbott, Peter M.; Rasmussen, Tine Lander; Palmer, A. P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)