Viser treff 201-215 av 215

    • U-Th chronology and formation controls of methane-derived authigenic carbonates from the Hola trough seep area, northern Norway 

      Sauer, Simone; Knies, Jochen; Lepland, Aivo; Sahy, Diana; Martma, Tõnu; Noble, Stephen R.; Schönenbergerb, Jasmin; Klug, Martin; Schubert, Carsten J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-20)
      We investigated methane-derived authigenic carbonate (MDAC) crusts and nodules from a cold seep site on the northern Norwegian continental shelf in ca. 220 m water depth to determine the timing and mode of their formation. Gas bubbling observed during remotely operated vehicle (ROV)-assisted sampling of MDAC crusts revealed ongoing seep activity. Authigenic carbonates were present as crusts on the ...
    • UAV photogrammetry and structure from motion to assess calving dynamics at Store Glacier, a large outlet draining the Greenland ice sheet 

      Ryan, Johnny C.; Hubbard, Alun Lloyd; Box, Jason E.; Todd, Joe; Christoffersen, Poul; Carr, J. Rachel; Holt, Tom O.; Snooke, Neal A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-06)
      This study presents the application of a costeffective, unmanned aerial vehicle (UAV) to investigate calving dynamics at a major marine-terminating outlet glacier draining the western sector of the Greenland ice sheet. The UAV was flown over Store Glacier on three sorties during summer 2013 and acquired over 2000 overlapping, geotagged images of the calving front at an ∼ 40 cm ground sampling ...
    • Undersjøiske daler og oljereservoar 

      Vorren, Tore Ola; Laberg, Jan Sverre (Chronicle; Kronikk, 2010-10-02)
    • Undersjøiske kjempeskred og flodbølger 

      Vorren, Tore Ola; Laberg, Jan Sverre (Chronicle; Kronikk, 2010-09-25)
    • Unravelling key controls on the rift climax to post-rift fill of marine rift basins: insights from 3D seismic analysis of the Lower Cretaceous of the Hammerfest Basin, SW Barents Sea 

      Marin Restrepo, Dora Luz; Escalona Varela, Alejandro; Grundvåg, Sten-Andreas; Olaussen, Snorre; Sandvik, Sara; Śliwińska, Kasia K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-19)
      In this study, we investigate key factors controlling the rift climax to post‐rift marine basin fill. We use two‐ and three‐dimensional seismic data in combination with sedimentological core descriptions from the Hammerfest Basin, south‐western Barents Sea to characterize and analyse the tectonostratigraphy and seismic facies of the Lower Cretaceous succession. Based on our biostratigraphic analyses, ...
    • Variability of present and past PAH concentrations in sediments of the SW Barents Sea 

      Junttila, Juho; Carroll, JoLynn; Dijkstra, Noortje (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-09)
      The concentration and distribution of polyaromatic hydrocarbons (PAHs) in surface and subsurface sediment samples from Tromsøflaket and Ingøydjupet, southwestern Barents Sea, were investigated in order to provide insight into the levels and origins of PAHs in a region with petroleum activities. PAH profiles in sediments were evaluated in context with sediment grain size and total organic carbon ...
    • Variations in benthic foraminiferal assemblages in the Tagus mud belt during the last 5700 years: Implications for Tagus River discharge 

      Dessandier, Pierre-Antoine; Bonnin, Jérôme; Malaizé, Bruno; Lambert, Clément; Tjallingii, Rik; Warden, Lisa; Sinninghe Damsté, Jaap S.; Kim, Jung-Hyun (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-31)
      We analyzed a 10-m sediment core retrieved at 82 m water depth off the coast of the Tagus River (Western Iberian Margin, Portugal) to investigate a linkage between variations in benthic foraminiferal assemblages and Tagus River discharge over the last 5700 years. Benthic foraminiferal assemblages were studied at high resolution in combination with the stable carbon and oxygen isotopic composition ...
    • Variations in gas and water pulses at an Arctic seep: fluid sources and methane transport 

      Hong, Wei-Li; Torres, Marta E.; Portnov, Aleksei D; Waage, Malin; Haley, B.; Lepland, Aivo (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-04-19)
      Methane fluxes into the oceans are largely dependent on the methane phase as it migrates upward through the sediments. Here we document decoupled methane transport by gaseous and aqueous phases in Storfjordrenna (offshore Svalbard) and propose a three‐stage evolution model for active seepage in the region where gas hydrates are present in the shallow subsurface. In a preactive seepage stage, solute ...
    • Variations in pockmark composition at the Vestnesa Ridge: Insights from marine controlled source electromagnetic and seismic data 

      Goswami, Bedanta K.; Weitemeyer, Karen A.; Bünz, Stefan; Minshull, Timothy A.; Westbrook, Graham K.; Ker, Stephan; Sinha, Martin C. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-10)
      The Vestnesa Ridge marks the northern boundary of a known submarine gas hydrate province in the west Svalbard margin. Several seafloor pockmarks at the eastern segment of the ridge are sites of active methane venting. Until recently, seismic reflection data were the main tool for imaging beneath the ridge. Coincident controlled source electromagnetic (CSEM), high‐resolution two‐dimensional (2‐D) ...
    • Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14C dates 

      Mohamed, Ezat M.; Rasmussen, Tine L.; Thornalley, David J.R.; Olsen, Jesper; Skinner, Luke C.; Hönisch, Bärbel; Groeneveld, Jeroen (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-10)
      Formation of deep water in the high‐latitude North Atlantic is important for the global meridional ocean circulation, and its variability in the past may have played an important role in regional and global climate change. Here we study ocean circulation associated with the last (de)glacial period, using water‐column radiocarbon age reconstructions in the Faroe‐Shetland Channel, southeastern Norwegian ...
    • Visualizing and interpreting surface displacement patterns on unstable slopes using multi-geometry satellite SAR interferometry (2D InSAR) 

      Eriksen, Harald Øverli; Lauknes, Tom Rune; Larsen, Yngvar; Corner, Geoffrey D.; Bergh, Steffen G; Dehls, John; Kierulf, Halfdan Pascal (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-05)
      It is well known that satellite radar interferometry (InSAR) is capable of measuring surface displacement with a typical accuracy on the order of millimeters to centimeters. However, when the true deformation vector differs from the satellite line-of-sight (LOS), the sensitivity decreases and interpretation of InSAR deformationmeasurements becomes challenging. By combining displacement data ...
    • Visualizing tephra deposits and sedimentary processes in the marine environment: The potential of X-ray microtomography 

      Griggs, Adam J.; Davies, Siwan M.; Abbott, Peter M.; Coleman, Mark; Palmer, Adrian P.; Rasmussen, Tine Lander; Johnston, Richard (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12-30)
      Localized tephra deposition in marine sequences is the product of many complex primary and secondary depositional processes. These can significantl y influence the potential applicability of tephra depos- its as isochronous marker horizons and current techniques, used in isolation, may be insufficient to fully unravel these processes. Here we demonstrate the innovative application of X-ray ...
    • Water column methanotrophy controlled by a rapid oceanographic switch 

      Steinle, Lea; Graves, Carolyn A.; Treude, Tina; Ferré, Benedicte; Biastoch, Arne; Bussmann, Ingeborg; Berndt, Christian; Krastel, Sebastian; James, Rachel H.; Behrens, Erik; Böning, Claus W.; Greinert, Jens; Sapart, Célia-Julia; Scheinert, Markus; Sommer, Stefan; Lehmann, Moritz F.; Niemann, Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-04-20)
      Large amounts of the greenhouse gas methane are released from the seabed to the water column, where it may be consumed by aerobic methanotrophic bacteria. The size and activity of methanotrophic communities, which determine the amount of methane consumed in the water column, are thought to be mainly controlled by nutrient and redox dynamics. Here, we report repeated measurements of methanotrophic ...
    • Water mass exchange between the Nordic Seas and the Arctic Ocean on millennial time scale during MIS 4–2 

      Rasmussen, Tine Lander; Thomsen, Erik; Nielsen, Tove (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      The climate of the last glaciation circa 65,000–25,000 years ago was interrupted by about 15 abrupt temperature fluctuations, the so-called Dansgaard-Oeschger events consisting of warm interstadials and cold stadials recorded in Greenland ice cores. The largest fluctuations occur in the North Atlantic region, but they have been registered over the most of the world. The events are linked to changes ...
    • Water redistribution in experimentally deformed natural milky quartz single crystals?Implications for H2O-weakening processes 

      Stünitz, H.; Thust, A.; Heilbronner, R.; Behrens, H.; Kilian, R.; Tarantola, A.; Fitz Gerald, J.D. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-22)
      Natural quartz single crystals were experimentally deformed in two orientations: (1) ⊥ to one prism plane and (2) in O+ orientation at 900 and 1000°C, 1.0 and 1.5 GPa, and strain rates of ~1 × 10−6 s−1. In addition, hydrostatic and annealing experiments were performed. The starting material was milky quartz, which consisted of dry quartz with a large number of fluid inclusions of variable size up ...