Now showing items 253-272 of 315

    • Sea ice and millennial-scale climate variability in the Nordic seas 90 kyr ago to present 

      Hoff, Ulrike; Rasmussen, Tine Lander; Stein, Ruediger; Ezat, Mohamed; Fahl, Kirsten (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-07-26)
      In the light of rapidly diminishing sea ice cover in the Arctic during the present atmospheric warming, it is imperative to study the distribution of sea ice in the past in relation to rapid climate change. Here we focus on glacial millennial-scale climatic events (Dansgaard/Oeschger events) using the sea ice proxy IP25 in combination with phytoplankton proxy data and quantification of diatom species ...
    • Sea ice and primary production proxies in surface sediments from a High Arctic Greenland fjord: Spatial distribution and implications for palaeoenvironmental studies 

      Ribeiro, Sofia; Sejr, Mikael K.; Limoges, Audrey; Heikkilä, Maija; Andersen, Thorbjørn Joest; Tallberg, Petra; Weckström, Kaarina; Husum, Katrine; Forwick, Matthias; Dalsgaard, Tage; Massé, Guillaume; Seidenkrantz, Marit-Solveig; Rysgaard, Søren (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-23)
      In order to establish a baseline for proxy-based reconstructions for the Young Sound–Tyrolerfjord system (Northeast Greenland), we analysed the spatial distribution of primary production and sea ice proxies in surface sediments from the fjord, against monitoring data from the Greenland Ecosystem Monitoring Programme. Clear spatial gradients in organic carbon and biogenic silica contents reflected ...
    • Sea-ice dynamics in an Arctic coastal polynya during the past 6500 years 

      Knies, Jochen; Pathirana, Irene Dorothea; Cabedo-Sanz, Patricia; Banica, Ana; Fabian, Karl; Rasmussen, Tine Lander; Forwick, Matthias; Belt, Simon T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-23)
      The production of high-salinity brines during sea-ice freezing in circum-arctic coastal polynyas is thought to be part of northern deep water formation as it supplies additional dense waters to the Atlantic meridional overturning circulation system. To better predict the effect of possible future summer ice-free conditions in the Arctic Ocean on global climate, it is important to improve our ...
    • Seabed morphology and sedimentary processes on high-gradient trough mouth fans offshore Troms, northern Norway 

      Rydningen, Tom Arne; Laberg, Jan Sverre; Kolstad, Vidar (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-01)
      Trough mouth fans (TMF) situated at the mouths of formerly glaciated cross-shelf troughs are important paleoclimatic archives. Whereas the sedimentary processes of large, low-gradient TMFs have received considerable interest, little attention has been paid to the other end member of this landform class, i.e. TMFs with higher slope gradients. Detailed swath-bathymetric data and seismic profiles from ...
    • Sediment transport on the Palos Verdes shelf, California 

      Ferré, Benedicte; Sherwood, Christopher R.; Wiberg, Patricia L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2010-02-01)
      Sediment transport and the potential for erosion or deposition have been investigated on the Palos Verdes (PV) and San Pedro shelves in southern California to help assess the fate of an effluent-affected deposit contaminated with DDT and PCBs. Bottom boundary layer measurements at two 60-m sites in spring 2004 were used to set model parameters and evaluate a one-dimensional (vertical) model of local, ...
    • Sedimentary ancient DNA from Lake Skartjørna, Svalbard: Assessing the resilience of arctic flora to Holocene climate change 

      Alsos, Inger Greve; Sjögren, Per Johan E.; Edwards, Mary E.; Landvik, Jon Y.; Gielly, Ludovic; Forwick, Matthias; Coissac, Eric; Brown, Antony G; Jakobsen, Leif Vidar; Merkel, Marie Kristine Føreid; Pedersen, Mikkel Winter (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-11)
    • Sedimentology and palynology of the Lower Cretaceous succession of central Spitsbergen: integration of subsurface and outcrop data 

      Grundvåg, Sten-A; Jelby, Mads Engholm; Śliwińska, Kasia Kamila; Nøhr-Hansen, Henrik; Aadland, Tore; Sandvik, Sara Elvelund; Tennvassås, Ingrid; Engen, Thea; Olaussen, Snorre (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-27)
      The Lower Cretaceous succession in Svalbard is commonly considered as an important analogue to age-equivalent strata on the Barents Shelf which are sporadically targeted by exploration wells. In this study, the stratigraphic and genetic relationship between the Rurikfjellet (open marine), Helvetiafjellet (paralic) and Carolinefjellet (open marine) formations of the Lower Cretaceous succession in ...
    • Sedimentology of the Lower Cretaceous at Kikutodden and Keilhaufjellet, southern Spitsbergen: implications for an onshore-offshore link 

      Grundvåg, Sten-Andreas; Olaussen, Snorre (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-10)
      Detailed sedimentological investigations of the Lower Cretaceous succession of southernmost Spitsbergen indicate deposition during a long-term fall and rise in relative sea level. The Rurikfjellet Formation shows an overall regressive development and consists of offshore deposits grading upwards into progradationally stacked shoreface parasequences. The overlying Helvetiafjellet Formation shows a ...
    • Seepage from an arctic shallow marine gas hydrate reservoir is insensitive to momentary ocean warming 

      Hong, Wei-Li; Torres, Marta E.; Carroll, JoLynn; Cremiere, Antoine; Panieri, Giuliana; Yao, Haoyi; Serov, Pavel (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-07)
      Arctic gas hydrate reservoirs located in shallow water and proximal to the sediment-water interface are thought to be sensitive to bottom water warming that may trigger gas hydrate dissociation and the release of methane. Here, we evaluate bottom water temperature as a potential driver for hydrate dissociation and methane release from a recently discovered, gas-hydrate-bearing system south of ...
    • Seismic evidence for complex sedimentary control of Greenland Ice Sheet flow 

      Kulessa, Bernd; Hubbard, Alun Lloyd; Booth, Adam D.; Bougamont, Marion; Dow, Christine F.; Doyle, Samuel H.; Christoffersen, Poul; Lindbäck, Katrin; Pettersson, Rickard; Fitzpatrick, Andrew A.W.; Jones, Glenn A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-16)
      The land-terminating margin of the Greenland Ice Sheet has slowed down in recent decades, although the causes and implications for future ice flow are unclear. Explained originally by a self-regulating mechanism where basal slip reduces as drainage evolves from low to high efficiency, recent numerical modeling invokes a sedimentary control of ice sheet flow as an alternative hypothesis. Although ...
    • Semi-quantitative reconstruction of early to late Holocene spring and summer sea ice conditions in the northern Barents Sea 

      Berben, Sarah Miche Patricia; Husum, Katrine; Navarro-Rodriguez, Alba; Belt, Simon T.; Sørensen, Steffen Aagaard (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-07)
      Semi-quantitative estimates of early to late Holocene spring sea ice concentration (SpSIC) andoccurrence of summer sea ice for the northern Barents Sea have been obtained by analysing the biomarkers IP<sub>25</sub>,brassicasterol and a tri-unsaturated highly branched isoprenoid lipid in a Holocene marine sediment core.Sub-surface water mass variations were derived from planktic foraminiferal assemblages ...
    • Semibrittle deformation and partial melting of perthitic K-feldspar: An experimental study 

      Negrini, Marianne; Stunitz, Holger; Nasipuri, Pritam; Menegon, Luca; Morales, Luiz F.G. (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • Shallow carbon storage in ancient buried thermokarst in the South Kara Sea 

      Portnov, Aleksei D; Mienert, Jürgen; Winsborrow, Monica; Andreassen, Karin; Vadakkepuliyambatta, Sunil; Semenov, Peter; Gataullin, Valery (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-25)
      Geophysical data from the South Kara Sea reveal U-shaped erosional structures buried beneath the 50–250 m deep seafloor of the continental shelf across an area of ~32 000 km<sup>2</sup>. These structures are interpreted as thermokarst, formed in ancient yedoma terrains during Quaternary interglacial periods. Based on comparison to modern yedoma terrains, we suggest that these thermokarst features ...
    • Shallow methane hydrate system controls ongoing, downslope sediment transport in a low-velocity active submarine landslide complex, Hikurangi Margin, New Zealand 

      Mountjoy, J.J.; Pecher, Ingo; Henrys, Stuart; Crutchley, Gareth; Barnes, P.M.; Plaza-Faverola, Andreia (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-10-14)
    • Significance of substrate soil moisture content for rockfall hazard assessment 

      Vick, Louise Mary; Zimmer, Valerie; White, Christopher; Massey, Chris; Davies, Tim (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-27)
      Rockfall modelling is an important tool for hazard analysis in steep terrain. Calibrating terrain parameters ensures that the model results more accurately represent the site-specific hazard. Parameterizing rockfall models is challenging because rockfall runout is highly sensitive to initial conditions, rock shape, size and material properties, terrain morphology, and terrain material properties. ...
    • Simulating seismic chimney structures as potential vertical migration pathways for CO2 in the Snøhvit area, SW Barents Sea: model challenges and outcomes 

      Tasianas, Alexandros; Mahl, Lena; Darcis, Melanie; Bünz, Stefan; Class, Holger (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-16)
      Carbon capture and storage (CCS) activities at the Snøhvit field, Barents Sea, will involve carrying out an analysis to determine which parameters affect the migration process of CO2 from the gas reservoir, to what degree they do so and how sensitive these parameters are to any changes. This analysis will aim to evaluate the effects of applying a broad but realistic range of reservoir, fault and gas ...
    • Some giant submarine landslides do not produce large tsunamis 

      Løvholt, Finn; Bondevik, Stein; Laberg, Jan Sverre; Kim, Jihwan; Boylan, Noel (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-07)
      Landslides are the second-most important cause of tsunamis after earthquakes, and their potential for generating large tsunamis depend on the slide process. Among the world's largest submarine landslides is the Storegga Slide that generated an ocean-wide catastrophic tsunami, while no traces of a tsunami generated from the similar and nearby Trænadjupet Slide have been found. Previous models for ...
    • Sources and turnover of organic carbon and methane in fjord and shelf sediments off Northern Norway 

      Sauer, Simone; Hong, Wei-Li; Knies, Jochen; Lepland, Aivo; Forwick, Matthias; Klug, Martin; Eichinger, Florian; Baranwal, Soma; Cremiere, Antoine; Chand, Shyam; Schubert, Carsten J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-10-22)
      To better understand the present and past carbon cycling and transformation processes in methane-influenced fjord and shelf areas of northern Norway, we compared two sediment cores from the Hola trough and from Ullsfjorden. We investigated (1) the organic matter composition and sedimentological characteristics to study the sources of organic carbon (C<sub>org</sub>) and the factors influencing ...
    • Splay fault branching from the Hikurangi subduction shear zone: Implications for slow slip and fluid flow 

      Plaza-Faverola, Andreia; Henrys, Stuart; Pecher, Ingo; Wallace, L.; Klaeschen, Dirk (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-25)
      Prestack depth migration data across the Hikurangi margin, East Coast of the North Island, New Zealand, are used to derive subducting slab geometry, upper crustal structure, and seismic velocities resolved to ∼14 km depth. We investigate the potential relationship between the crustal architecture, fluid migration, and short-term geodetically determined slow slip events. The subduction interface is ...
    • Spreading of drill cuttings and sediment recovery of three exploration wells of different ages, SW Barents Sea, Norway 

      Junttila, Juho; Dijkstra, Noortje; Sørensen, Steffen Aagaard (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-14)
      Five stations (≤250 m from the well heads) from three exploration wells of different ages from the SW Barents Sea were studied to investigate the spreading of drill cuttings and sediment quality. Two of the wells were drilled before the restriction of use of oil-based drilling fluids (1993). Elevated concentrations of Ba were found in sediments near all the wells with the highest concentrations ...