Now showing items 21-40 of 315

    • Bottom-simulating reflector dynamics at Arctic thermogenic gas provinces: An example from Vestnesa Ridge, offshore west Svalbard 

      Plaza-Faverola, Andreia; Vadakkepuliyambatta, Sunil; Hong, Wei-Li; Mienert, Jurgen; Bünz, Stefan; Chand, Shyam; Greinert, Jens (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06)
    • Brine formation in relation to climate changes and ice retreat during the last 15,000 years in Storfjorden, Svalbard, 76–78°N 

      Rasmussen, Tine Lander; Thomsen, Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-10-06)
      Storfjorden, Svalbard, is an area of intense brine formation. The brine is cold, dense, rich in oxygen and CO2, and has reduced pH. Storfjorden is unique because it contains well-preserved agglutinated foraminifera dating back to the beginning of the last deglaciation. We have investigated the distribution of calcareous and agglutinated benthic foraminifera, benthic oxygen and carbon isotopes, ...
    • The build-up, configuration, and dynamical sensitivity of the Eurasian ice-sheet complex to Late Weichselian climatic and oceanic forcing 

      Patton, Henry; Hubbard, Alun Lloyd; Andreassen, Karin; Winsborrow, Monica; Stroeven, Arjen P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-01)
      The Eurasian ice-sheet complex (EISC) was the third largest ice mass during the Last Glacial Maximum (LGM), after the Antarctic and North American ice sheets. Despite its global significance, a comprehensive account of its evolution from independent nucleation centres to its maximum extent is conspicuously lacking. Here, a first-order, thermomechanical model, robustly constrained by empirical evidence, ...
    • Carbon isotope (d13C) excursions suggest times of major methane release during the last 14 ka in Fram Strait, the deep-water gateway to the Arctic 

      Consolaro, Chiara; Rasmussen, Tine Lander; Panieri, Giuliana; Mienert, Jurgen; Bünz, Stefan; Sztybor, Kamila (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • Cascading lake drainage on the Greenland Ice Sheet triggered by tensile shock and fracture 

      Christoffersen, Poul; Bougamont, Marion; Hubbard, Alun; Doyle, Samuel H.; Grigsby, Shane; Pettersson, Rickard (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-14)
      Supraglacial lakes on the Greenland Ice Sheet are expanding inland, but the impact on ice flow is equivocal because interior surface conditions may preclude the transfer of surface water to the bed. Here we use a well-constrained 3D model to demonstrate that supraglacial lakes in Greenland drain when tensile-stress perturbations propagate fractures in areas where fractures are normally absent or ...
    • Cenozoic Erosion of the Barents Sea Shelf, Norwegian Arctic: A Review 

      Lasabuda, Amando Putra Ersaid; Laberg, Jan Sverre; Knutsen, Stig-Morten; Rydningen, Tom Arne (Conference object; Konferansebidrag, 2018-12)
      The circum North Atlantic-Arctic continental margin and adjacent land areas have experienced several episodes of uplift and erosion during the Cenozoic. A series of efforts quantifying this erosion for the Barents Sea shelf, where the Arctic shelf is at its widest and deepest have been done since the early 90’s using different methods. As the seismic and well database have expanded considerably, ...
    • The Cenozoic pre-glacial tectono-stratigraphy and erosion estimates for the NW Barents Sea 

      Lasabuda, Amando Putra Ersaid; Laberg, Jan Sverre; Knutsen, Stig-Morten; Safronova, Polina (Conference object; Konferansebidrag, 2017-04-24)
    • Cenozoic tectonostratigraphy and pre-glacial erosion: A mass-balance study of the northwestern Barents Sea margin 

      Lasabuda, Amando Putra Ersaid; Laberg, Jan Sverre; Knutsen, Stig-Morten; Safronova, Polina (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-26)
      <p>The evolution of the northwestern Barents Sea continental margin, part of a NW-SE trending mega shear zone, has been reconstructed in order to quantify the sedimentation and erosion affecting this area during and after its formation in the Paleogene–Neogene. This development was closely related to the sea-floor opening of the Norwegian-Greenland Sea. Our study incorporated 2D seismic data, well ...
    • Changes in sea ice cover and ice sheet extent at the Yermak Plateau during the last 160 ka - Reconstructions from biomarker records 

      Kremer, A; Stein, R; Fahl, K.; Ji, Z; Yang, Z; Wiers, Steffen; Matthiessen, J; Forwick, Matthias; Löwemark, Ludvig; O'Regan, M; Chen, J; Snowball, Ian (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-15)
      The Yermak Plateau is located north of Svalbard at the entrance to the Arctic Ocean, i.e. in an area highly sensitive to climate change. A multi proxy approach was carried out on Core PS92/039-2 to study glacial-interglacial environmental changes at the northern Barents Sea margin during the last 160 ka. The main emphasis was on the reconstruction of sea ice cover, based on the sea ice proxy ...
    • Changing surface–atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland 

      Charalampidis, C.; Van As, D.; Box, J.E.; van den Broeke, M.R.; Colgan, W.T.; Doyle, S.H.; Hubbard, Alun Lloyd; MacFerrin, M.; Machguth, H.; Smeets, C.J.P.P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-18)
      We present 5 years (2009–2013) of automatic weather station measurements from the lower accumulation area (1840 m a.s.l. – above sea level) of the Greenland ice sheet in the Kangerlussuaq region. Here, the summers of 2010 and 2012 were both exceptionally warm, but only 2012 resulted in a strongly negative surface mass budget (SMB) and surface meltwater run-off. The observed run-off was ...
    • Character of seismic motion at a location of a gas hydrate-bearing mud volcano on the SW Barents Sea margin 

      Franek, Peter; Mienert, Jürgen; Buenz, Stefan; Géli, Louis (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-07-09)
      The Håkon Mosby mud volcano (HMMV) at 1270 m water depth on the SW Barents Sea slope has been intensively studied since its discovery in 1989. A variety of sensors monitored morphological, hydrological, geochemical, and biological parameters in the HMMV area. An ocean bottom seismometer deployment allowed us to register seismic motion for 2 years, from October 2008 to October 2010. The analysis of ...
    • Characterization of Carbonate Crust from a Recently Discovered Methane Seep on the North Atlantic Continental Margin of the USA 

      Gabitov, Rinat; Borrelli, Chiara; Buettner, Jacob; Kirkland, Brenda; Skarke, Adam; Trail, Dustin; Garner, Brittany; Testa, Maurice; Wahidi, Mahnaz; Hoff, Christopher; Khasanov, Salavat; Panieri, Giuliana; Thirumalai, Roobanvenkatesh; Thomas, Jay; Weremeichik, Jeremy; Zverkova, Irina (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-26)
      This study is focused on mineralogical and chemical characterization of an authigenic carbonate rock (crust) collected at a recently discovered cold seep on the US North Atlantic continental margin. X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicate that the carbonate rock is composed of microcrystalline aragonite cement, white acicular aragonite crystals (AcAr), equant quartz ...
    • Chemosynthesis influences food web and community structure in high-Arctic benthos 

      Åström, Emmelie; Carroll, Michael; Sen, Arunima; Niemann, Helge; Ambrose Jr., William G.; Lehmann, Moritz F; Carroll, JoLynn (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-25)
      Cold seeps are locations where seafloor communities are influenced by the seepage of methane and other reduced compounds from the seabed. We examined macro-infaunal benthos through community analysis and trophic structure using stable isotope analysis at 3 seep locations in the Barents Sea. These seeps were characterized by high densities of the chemosymbiotic polychaetes Siboglinidae, clade Frenulata ...
    • CO2 flux over young and snow-covered Arctic pack ice in winter and spring 

      Nomura, Daiki; Granskog, Mats A.; Fransson, Agneta; Chierici, Melissa; Silyakova, Anna; Ohshima, Kay; Cohen, Lana; Delille, Bruno; Hudson, Stephen R.; Dieckmann, Gerhard (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-05)
      Rare CO2 flux measurements from Arctic pack ice show that two types of ice contribute to the release of CO2 from the ice to the atmosphere during winter and spring: young, thin ice with a thin layer of snow and older (several weeks), thicker ice with thick snow cover. Young, thin sea ice is characterized by high salinity and high porosity, and snow-covered thick ice remains relatively warm ( >  −7.5 °C) ...
    • Cohesive and mixed sediment in the Regional Ocean Modeling System (ROMS v3.6) implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST r1234) 

      Sherwood, Christopher R.; Aretxabaleta, Alfredo L.; Harris, Courtney K.; Rinehimer, J. Paul; Verney, Romaric; Ferré, Benedicte (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-14)
      We describe and demonstrate algorithms for treating cohesive and mixed sediment that have been added to the Regional Ocean Modeling System (ROMS version 3.6), as implemented in the Coupled Ocean–Atmosphere–Wave– Sediment Transport Modeling System (COAWST Subversion repository revision 1234). These include the following: floc dynamics (aggregation and disaggregation in the water column); changes in ...
    • Cold-seep ostracods from the western Svalbard margin: direct palaeo-indicator for methane seepage? 

      Yasuhara, Moriaki; Sztybor, Kamila; Rasmussen, Tine Lander; Okahashi, Hisayo; Sato, Runa; Tanaka, Hayato (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-05)
      Despite their high abundance and diversity, microfossil taxa adapted to a particular chemosynthetic environment have rarely been studied and are therefore poorly known. Here we report on an ostracod species, Rosaliella svalbardensis gen. et sp. nov., from a cold methane seep site at the western Svalbard margin, Fram Strait. The new species shows a distinct morphology, different from other ...
    • Comment on“The Keisarhjelmen detachment records Silurian–Devonian extensional collapse in Northern Svalbard” 

      Dallmann, Winfried; Piepjohn, Karsten (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-30)
      <p><i>Introduction</i>: The discussed area has been investigated since the 1960s. Scientists of the Norwegian Polar Institute, the Cambridge scholar environment, the University of Münster and others have mapped, described, interpreted and contributed to the discussion through decades. Very little of this is reflected in the paper by Braathen, Osmundsen, Maher, and Ganerød, (2018). A discussion of ...
    • Complementary biomarker-based methods for characterising Arctic sea ice conditions: A case study comparison between multivariate analysis and the PIP25 index 

      Koseoglu, Denizcan; Belt, Simon T.; Smik, Lukas; Yao, Haoyi; Panieri, Giuliana; Knies, Jochen (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-10)
      The discovery of IP25 as a qualitative biomarker proxy for Arctic sea ice and subsequent introduction of the so-called PIP25 index for semi-quantitative descriptions of sea ice conditions has significantly advanced our understanding of long-term paleo Arctic sea ice conditions over the past decade. We investigated the potential for classification tree1 (CT) models to provide a further approach ...
    • Conduit processes during the February 11, 2010 Vulcanian eruption of Soufriere Hills, Montserrat 

      Burgisser, Alain; Bechon, Tonin; Chevalier, Laure; Collombet, Marielle; Arbaret, Laurent; Forien, Melanie (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-29)
      We analyzed pumice from the February 11, 2010 Vulcanian explosion that immediately followed a large dome collapse at Soufrière Hills volcano. We obtained pre-explosive values of porosity, pressure, and depth by combining textural analyses and glass water content determinations. Our data suggest that the February 2010 explosion evacuated the upper 3 km of the conduit from the dense magma (≤10 vol% ...
    • The configuration, sensitivity and rapid retreat of the Late Weichselian Icelandic ice sheet 

      Patton, Henry; Hubbard, Alun Lloyd; Bradwell, T.; Schomacker, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-03)
      The fragmentary glacial-geological record across the Icelandic continental shelf has hampered reconstruction of the volume, extent and chronology of the Late Weichselian ice sheet particularly in key offshore zones. Marine geophysical data collected over the last two decades reveal that the ice sheet likely attained a continental shelf-break position in all sectors during the Last Glacial Maximum, ...