Now showing items 681-700 of 1012

    • Thermogenic methane injection via bubble transport into the upper Arctic Ocean from the hydrate-charged Vestnesa Ridge, Svalbard 

      Smith, Andrew James; Mienert, Jurgen; Bünz, Stefan; Greinert, Jens (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-04-21)
      We use new gas‐hydrate geochemistry analyses, echosounder data, and three‐dimensional P‐Cable seismic data to study a gas‐hydrate and free‐gas system in 1200 m water depth at the Vestnesa Ridge offshore NW Svalbard. Geochemical measurements of gas from hydrates collected at the ridge revealed a thermogenic source. The presence of thermogenic gas and temperatures of ∼3.3°C result in a shallow top of ...
    • Enhanced CO2 uptake at a shallow Arctic Ocean seep field overwhelms the positive warming potential of emitted methane 

      Pohlman, John; Greinert, Jens; Ruppel, Carolyn; Silyakova, Anna; Vielstädte, Lisa; Casso, Michael; Mienert, Jürgen; Bünz, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-05-08)
      Continued warming of the Arctic Ocean in coming decades is projected to trigger the release of teragrams (1 Tg = 106 tons) of methane from thawing subsea permafrost on shallow continental shelves and dissociation of methane hydrate on upper continental slopes. On the shallow shelves (<100 m water depth), methane released from the seafloor may reach the atmosphere and potentially amplify global ...
    • Geofaglig kunnskap og holdninger til norsk petroleumsnæring. En casestudie av Alta/Gohta 

      Forsberg, Mariann (Master thesis; Mastergradsoppgave, 2018-05-15)
      Denne oppgaven har som hovedfokus å belyse holdninger og geofaglig kunnskap knyttet til norsk petroleumsnæring. Oppgaven tar utgangspunkt i olje- og gassfunnene Alta/Gohta i Barentshavet. Et geofaglig litteraturstudie har blitt gjennomført for å oppnå en forståelse av funnenes geologi og særegenheter. Intervjuer med norsk petroleumsnærings hovedaktører; olje- og energidepartementet, oljedirektoratet, ...
    • Geochemical characterisation of northern Norwegian fjord surface sediments: A baseline for further paleo-environmental investigations 

      Faust, Johan Christoph; Scheiber, Thomas; Fabian, Karl; Vogt, Christoph; Knies, Jochen (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-26)
      Norwegian fjord sediments are promising archives for very high resolution records of past environmental changes. Recent investigations of the modern depositional environment within fjords revealed that the accurate quantification of the inputs, sources, and sedimentary preservation of organic and inorganic material is crucial to decipher long term past climate signals in the sedimentary record ...
    • Identifying past petroleum exploration related drill cutting releases and influences on the marine environment and benthic foraminiferal communities, Goliat Field, SW Barents Sea, Norway 

      Sørensen, Steffen Aagaard; Junttila, Juho; Dijkstra, Noortje (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-01)
      The present multiproxy investigation of marine sediment cores aims at: 1) Identifying dispersion of petroleum exploration related drill cutting releases within the Goliat Field, Barents Sea in 2006/07 and 2) Assessing past and present influence of drill cuttings on the marine environment. The cores were recovered 5, 30, 60, 125 and 250 m from the drill site in the eastward downstream direction.<p> ...
    • 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) ...
    • Formation of a large submarine crack during the final stage of retrogressive mass wasting on the continental slope offshore northern Norway 

      Laberg, Jan Sverre; Baeten, Nicole Jeanne; Lågstad, Petter Arthur; Forwick, Matthias; Vorren, Tore Ola (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-08-30)
      High-resolution swath-bathymetry data integrated with sub-bottom profiles and single-channel seismics reveal an 18 km long, up to 1000 m wide and 10-15 m deep crack located approx. 4 km upslope from a slide scar on the continental slope off northern Norway. This crack is formed by subsidence of the sea-floor sediments to a depth of 120 m due to downslope movement of a ~80 km2 large sediment slab ...
    • Triassic Channel Systems on the northern Loppa High, SW Barents Sea 

      Arntzen, Marit (Master thesis; Mastergradsoppgave, 2018-06-07)
      During the Triassic, the Barents Sea Basin was filled with sediments from the Uralian and Caledonian mountain belts. High sediment yield and large river systems made progradation possible, resulting in an alluvial to deltaic plain stretching from the mountain belts in the south east to Spitsbergen in the north.This thesis focuses on the northwestern part of the Loppa High area, SW Barents Sea. The ...
    • The regional upper Paleozoic development of the SE part of the Norwegian Barents Sea - from seismic interpretation 

      Slettehaug, Hanne-Lise (Master thesis; Mastergradsoppgave, 2018-05-15)
      This thesis focuses on the Barents Sea South East (BSSE), and the overall goal has been to investigate the regional upper Paleozoic development in the SE part of the Barents Sea. After more than four decades of negotiation between Norway and Russia, a delineation agreement came in effect in 2011. Today, the area known as BSSE is opened up for petroleum operations. As part of the opening of the BSSE, ...
    • Ore petrography and fluid evolution in the Cu-(Zn) VMS deposits at Sulitjelma, Northern Norway 

      Birkeland, Andre (Master thesis; Mastergradsoppgave, 2018-05-29)
      The Sulitjelma deposits, Nordland, Northern Norway, with more than 20 Zn-Cu ore bodies (total tonnage excesses 35 Mt of ore at 1.84 % Cu, 0.86 % Zn, 10 g/t Ag and 0.25 g/t Au) have been described as a classic example of the Zn-Cu volcanogenic massive sulfide (VMS) mineralization. The mineralization is spatially associated with metamorphosed mafic rocks of Ordovician age. Both, ore bodies and their ...
    • The origin of quartz-carbonate veins hosted by ductile shear zones of the Astridal Supracrustal Belt, West-Troms Basement Complex. 

      Forslund, Thea Mathilde (Master thesis; Mastergradsoppgave, 2018-05-29)
      An approximately 1 meter wide NE-SW-oriented mylonitic shear zone hosts hydrothermally precipitated quartz and carbonate veins. The shear zone mainly consists of a secondary mylonitic fabric enriched in chlorite. A similar mylonitic shear zone striking NE-SW, oriented parallel to the axial plane of a F3-fold, consists of the same secondary mylonitic chloritized fabric and are therefore assumingly ...
    • Comparison of 3D and 2D rockfall models. Considering terrain model quality effect on respective model performances 

      Hind, Håvard (Master thesis; Mastergradsoppgave, 2018-05-15)
      Rockfalls are blocks of rock that bounce and roll down slopes. They are commonly detached from rock-slopes with inclinations over 40-45°. They embody high energy and mobility and are a major cause of landslide related deaths. Rockfalls can be simulated using empirical relationships and modelling, of which 2D and 3D variants exist for the latter. 3D models allow for rock fragment- and surface shape ...
    • Regional structural analysis of rock slope failure types, mechanisms and controlling bedrock structures in Kåfjorden, Troms 

      Andresen, Maren Lund (Master thesis; Mastergradsoppgave, 2018-05-15)
      Unstable areas producing rock slope failures come with large consequences. The understanding of why and where they might occur is necessary to mitigate damage and prevent casualties. A total of 133 unstable rock slopes have been detected in Troms, Northern Norway, evidencing that a great focus on these geohazards is important. This study has focused on seven unstable rock slopes in Kåfjorden, Troms, ...
    • Steinsprang. Simulering, bevegelsesanalyse, struktur- og geomorfologisk undersøkelse av steinsprangområdet over Holmen ved Oksfjellet, Kåfjord, Troms. 

      Haukenes, Håvard Lytskjold (Master thesis; Mastergradsoppgave, 2018-05-14)
      Vurdering av skredfare og sikringstiltak i Kåfjord kommune i Troms viste i 2012 at en driftsbygning ved Holmen i Kåfjorddalen var utsatt for steinsprang fra Oksfjellet. Det er registrert flere steinsprang i tillegg til bevegelser i et mindre fjellparti under toppen av Oksfjellet. Studieområdet over Holmen har dermed et unikt potensiale for å studere flere problemstillinger tilknyttet steinsprang. ...
    • Reconstructing the retreat dynamics of the Bjørnøyrenna Ice Stream based on new 3D seismic data from the central Barents Sea 

      Piasecka, Emilia Daria; Winsborrow, Monica; Andreassen, Karin; Stokes, Chris R. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-01)
      The stability of contemporary ice sheets is influenced by the discharge from ice streams - corridors of fast-flowing ice bounded by ice flowing an order of magnitude slower. Reconstructions of palaeo-ice stream dynamics contribute to our understanding of ice stream sensitivity to the ocean-climate system and can aid in the numerical modelling and prediction of future changes in contemporary ice ...
    • Glacial isostatic adjustment associated with the Barents Sea ice sheet: A modelling inter-comparison 

      Auriac, Amandine; Whitehouse, P.L.; Bentley, M.J.; Patton, Henry; Lloyd, J.M.; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-01)
      The 3D geometrical evolution of the Barents Sea Ice Sheet (BSIS), particularly during its late-glacial retreat phase, remains largely ambiguous due to the paucity of direct marine- and terrestrial-based evidence constraining its horizontal and vertical extent and chronology. One way of validating the numerous BSIS reconstructions previously proposed is to collate and apply them under a wide range ...
    • Atmospheric circulation patterns associated with avalanche cycles in the Troms region 

      Jenssen, Marius (Master thesis; Mastergradsoppgave, 2018-05-15)
      Snow avalanches endangers human lives and infrastructure situated in alpine environments during the winter season. Occurrence of avalanche activity is a product of processes taking place in the snow cover situated in steep terrain, which are governed by meteorological conditions induced by synoptic weather patterns. Avalanche forecasting can therefore better forecast avalanche activity if they ...
    • Deposits and processes on the tide-influenced fjord-head delta in Dicksonfjorden, Svalbard 

      Kvam, Maria Huse (Master thesis; Mastergradsoppgave, 2018-05-15)
      This study investigates for the first time the tide-influenced fjord-head delta in Dicksonfjorden, a fjord in central Spitsbergen, Svalbard. In order to examine the deposits and processes, sediment cores, surface observations and bulk samples have been obtained. Sedimentary facies, log transects and composite logs are presented. Sediment cores are dated with the 210Pb dating method to provide an ...
    • Sedimentation in Lake Nordlaguna - a closed basin on Jan Mayen 

      Christoffersen, Marianne (Master thesis; Mastergradsoppgave, 2018-05-15)
      This thesis focuses on the lake Nordlaguna on Jan Mayen. Nordlaguna is closed basin separated from the ocean by a barrier and surrounded by steep mountains and valleys. The lake has the potential to be a paleoclimatic archive and provide information about the unknown sea-level history of the island. When lake sediments are used in paleoclimatic studies, it is useful to acquire knowledge about the ...
    • The Late Paleozoic development of the Ottar basin from seismic 3D interpretation 

      Tonstad, Sigurd August (Master thesis; Mastergradsoppgave, 2018-05-15)
      The Late Paleozoic sedimentary environments of the Ottar basin in the SW Barents Sea was studied using five 3D seismic surveys. By the use of seismic stratigraphic analysis and correlation to wells located in close proximity to the study area, the Paleozoic succession has been subdivided into 4 main units: Billefjorden Group (Late Devonian – Mid Carboniferous), Gipsdalen Group (Mid Carboniferous – ...