Viser treff 901-920 av 1121

    • Thermal conditions and kinematics associated with final emplacement of the Lyngen nappe 

      Klæbo, Erik Vågå (Master thesis; Mastergradsoppgave, 2017-05-15)
      The tectonic boundary of between the Lyngen magmatic complex and the underlaying Nordmannvik have been examined for kinematic indicators. This boundary is characterised by an amphibole facies garnet-mica-kyanite gneiss overlain by a greenschist facies amphibolite/meta-gabbro succession separated by heavily foliated and lineated garnet-mica schist, phyllites and quartzites. Two main populations of ...
    • Microstructural changes during melt-assisted modification of quartzofeldspatic rocks. An example from the Eger Complex, North-Western Bohemian Massif 

      Hafne, Kristine (Master thesis; Mastergradsoppgave, 2017-05-15)
      The Eger Complex is situated in the Saxothuringian domain at the western margin of Bohemian Massif (Czech Republic). Migmatitic orthogneisses associated with granofelses and high-pressure felsic granulites make up the majority of the complex, which is interpreted as an upper crystalline nappe exhumed from underneath the fore-arc Teplá-Barrandian domain during the Variscan orogeny. Studies conducted ...
    • Drill cutting release in Ingøydjupet, SW Barents Sea from a well drilled in 1987, and its impact on benthic foraminifera 

      Berg, Julie (Master thesis; Mastergradsoppgave, 2017-05-15)
      In the nearby areas of the SW Barents Sea, large hydrocarbon reserves have been identified. During drilling procedures, drill cuttings are produced and some are released to sea. The disposal of drill cuttings may cause environmental degradation to the marine environment. Increasing petroleum activities, therefore requires further knowledge of ocean current transportation of fine sediment particles ...
    • Connection between chemical zonation and crystallographic preferred orientation as an indicator for the fabric development in eclogites. Example from the Saxothuringian eclogites, Bohemian massif, Czech Republic 

      Finstad, Ane Kongsro (Master thesis; Mastergradsoppgave, 2017-05-15)
      The presence of eclogites is one of the strongest evidences for high pressure metamorphism, and for the presence of a paleo subduction zone. Deformation of eclogites can yield important information about the kinematics of subduction zones. The main mechanism for fabric development in eclogites is still a matter of debate among various research groups and has split the field in two. Most previous ...
    • Shallow gas accumulations and fluid flow in the vicinity of the Goliat field, SW Barents Sea 

      Paulsen, Renate Strugstad (Master thesis; Mastergradsoppgave, 2017-05-15)
      This thesis focuses on the Goliat area located in the Hammerfest Basin, SW Barents Sea. The overall aim of this study is to increase the understanding of fluid flow processes between deeper thermogenic sources, and shallow gas accumulations. Indications of an active fluid flow system has been observed throughout the southwestern Barents Sea. Much of the fluid flow from deep hydrocarbon reservoirs ...
    • Shallow stratigraphic cores NW of Bjørnøya, results and implications 

      Eikelmann, Isak Emil Skadsem (Master thesis; Mastergradsoppgave, 2017-05-15)
      Two shallow boreholes, 7418/01-U-01 and 7517/12-U-01, were in 1994 drilled by IKU / SINTEF on behalf of the Norwegian Petroleum Directorate (NPD) northwest of Bjørnøya in the western Barents Sea. These were part of a program totalling nine boreholes at six different locations between Bjørnøya and Svalbard. This area is not opened for petroleum activity, and the shallow boreholes were aimed at ...
    • Carbonate concretions in an ice-contact delta, Skarmunken, Ullsfjord, northern Norway 

      Amundsen, Mats (Master thesis; Mastergradsoppgave, 2017-03-10)
      At Skarmunken, a small village south of Ullsfjord, northern Troms, Norway, an outcrop containing carbonate concretions have been investigated. From sedimentary logging, five facies (facies A-E) have been classified by their grading and composition. Depositional data from logs, maximum pebble size (MPS) and earlier investigations suggests an ice-contact delta. TOC/TS data have revealed a dominantly ...
    • 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 ...
    • Paleo-methane emissions recorded in foraminifera near the landward limit of the gas hydrate stability zone offshore western Svalbard 

      Panieri, Giuliana; Graves, Carolyn; James, Rachel (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-02-26)
      We present stable isotope and geochemical data from four sediment cores from west of Prins Karls Forland (ca. 340 m water depth), offshore western Svalbard, recovered from close to sites of active methane seepage, as well as from shallower water depths where methane seepage is not presently observed. Our analyses provide insight into the record of methane seepage in an area where ongoing ocean ...
    • A late-Holocene multi-proxy record from the northern Norwegian margin: Temperature and salinity variability 

      Berben, Sarah Miche Patricia; Husum, Katrine; Sørensen, Steffen Aagaard (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-01)
      To elucidate the natural variability of Atlantic and Coastal water, a late-Holocene multi-proxy analysis is performed on a marine sediment core from the northern Norwegian margin. This includes planktic foraminiferal fauna and their preservation indicators, stable isotopes (δ18Oc, δ13C), sub-surface temperature (SSTMg/Ca) and salinity (SSS) records based on paired Mg/Ca and δ18Oc measurements of ...
    • The influence of a model subglacial lake on ice dynamics and internal layering 

      Gudlaugsson, Eythor; Humbert, Angelika; Kleiner, Thomas; Kohler, Jack; Andreassen, Karin (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-05)
      As ice flows over a subglacial lake, the drop in bed resistance leads to an increase in ice velocities and a draw down of isochrones and cold ice. The ice surface flattens as it adjusts to the lack of resisting forces at the base. The rapid transition in velocity induces changes in ice viscosity and releases deformation energy that can raise the temperature locally. Recent studies of Antarctic ...
    • Gas hydrate and free gas detection using seismic quality factor estimates from high-resolution P-cable 3D seismic data 

      Singhroha, Sunny; Bünz, Stefan; Plaza-Faverola, Andreia; Chand, Shyam (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-09-23)
      We have estimated the seismic attenuation in gas hydrate and free-gas-bearing sediments from high-resolution P-cable 3D seismic data from the Vestnesa Ridge on the Arctic continental margin of Svalbard. P-cable data have a broad bandwidth (20–300 Hz), which is extremely advantageous in estimating seismic attenuation in a medium. The seismic quality factor (Q), the inverse of seismic attenuation, ...
    • Submarginal drumlin formation and late Holocene history of Fláajökull, southeast Iceland 

      Jónsson, Sverrir A.; Benediktsson, Ívar Örn; Ingólfsson, Ólafur; Schomacker, Anders; Bergsdóttir, Helga Lucia; Jacobson Jr., William R.; Linderson, Hans (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Fláajökull is a non-surging outlet glacier draining the south-eastern part of the Vatnajökull, southeast Iceland. Fláajökull was stationary or advanced slightly between 1966 and 1995 and formed a prominent end moraine. Glacial retreat since then has revealed a cluster of 15 drumlins. This study focuses on the morphology and sedimentology of the drumlins. They are 100–600 m long, 40–130 m wide, and ...
    • Production of fluorescent dissolved organic matter in Arctic Ocean sediments 

      Chen, Meilian; Kim, Ji-Hoon; Nam, Seung-Il; Niessen, Frank; Hong, Wei-Li; Kang, Moo-Hee; Hur, Jin (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Little is known about the production of fluorescent dissolved organic matter (FDOM) in the anoxic oceanic sediments. In this study, sediment pore waters were sampled from four different sites in the Chukchi-East Siberian Seas area to examine the bulk dissolved organic carbon (DOC) and their optical properties. The production of FDOM, coupled with the increase of nutrients, was observed above the ...
    • Arctic megaslide at presumed rest 

      Geissler, Wolfram H.; Gebhardt, Catalina; Gross, Felix; Wollenburg, Jutta; Jensen, Laura; Schmidt-Aursch, Mechita; Krastel, Sebastian; Elger, Judith; Osti, Giacomo (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Slope failure like in the Hinlopen/Yermak Megaslide is one of the major geohazards in a changing Arctic environment. We analysed hydroacoustic and 2D high-resolution seismic data from the apparently intact continental slope immediately north of the Hinlopen/Yermak Megaslide for signs of past and future instabilities. Our new bathymetry and seismic data show clear evidence for incipient slope ...
    • Freshwater ostracods (Crustacea) and environmental variability of polygon ponds in the tundra of the Indigirka Lowland, north-east Siberia 

      Schneider, Andrea; Wetterich, Sebastian; Schirrmeister, Lutz; Herzschuh, Ulrike; Meyer, Hanno; Pestryakova, Luidmila A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Freshwater ostracods (Crustacea, Ostracoda) are valuable biological indicators. In Arctic environments, their habitat conditions are barely known and the abundance and diversity of ostracods is documented only in scattered records with incomplete ecological characterization. To determine the taxonomic range of ostracod assemblages and their habitat conditions in polygon ponds in the Indigirka Lowland, ...
    • Depositional environment, ichnological features and oxygenation of Permian to earliest Triassic marine sediments in central Spitsbergen, Svalbard 

      Uchman, Alfred; Hanken, Nils-Martin; Nielsen, Jesper Kresten; Grundvåg, Sten-Andreas; Piasecki, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Late Early Permian–lowermost Triassic carbonate, siliceous (spiculites) and clastic marine sediments in the Marmierfjellet area (Isfjorden, central Spitsbergen) contain a relatively diverse and abundant trace fossil assemblage providing important information about the depositional processes. The Vøringen Member (Late Artinskian–Kungurian) of the Kapp Starostin Formation (Late Artinskian–? Changhsingian) ...
    • Timescales of methane seepage on the Norwegian margin following collapse of the Scandinavian Ice Sheet 

      Cremiere, Antoine; Lepland, Aivo; Chand, Shyam; Sahy, Diana; Condon, Daniel J.; Noble, Stephen R.; Martma, Tõnu; Thorsnes, Terje; Sauer, Simone; Brunstad, Harald (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-11)
      Gas hydrates stored on continental shelves are susceptible to dissociation triggered by environmental changes. Knowledge of the timescales of gas hydrate dissociation and subsequent methane release are critical in understanding the impact of marine gas hydrates on the ocean–atmosphere system. Here we report a methane efflux chronology from five sites, at depths of 220–400 m, in the southwest Barents ...
    • Two-stage exhumation of subducted Saxothuringian continental crust records underplating in the subduction channel and collisional forced folding (Krkonoše-Jizera Mts., Bohemian Massif) 

      Jerabek, Petr; Konopasek, Jiri; Žáčková, Eliška (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-08)
      The Krkonoše-Jizera Massif in the northern part of the Variscan Bohemian Massif provides insight into the exhumation mechanisms for subducted continental crust. The studied region exposes a relatively large portion of a flat-lying subduction-related complex that extends approximately 50 km away from the paleosuture. wide extent of HP-LT metamorphism has been confirmed by new P-T estimates indicating ...
    • Ice-sheet-driven methane storage and release in the Arctic 

      Portnov, Aleksei D; Vadakkepuliyambatta, Sunil; Mienert, Jurgen; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-07)
      It is established that late-twentieth and twenty-first century ocean warming has forced dissociation of gas hydrates with concomitant seabed methane release. However, recent dating of methane expulsion sites suggests that gas release has been ongoing over many millennia. Here we synthesize observations of B1,900 fluid escape features—pockmarks and active gas flares—across a previously glaciated ...