• Abiotic methane from ultraslow-spreading ridges can charge Arctic gas hydrates 

      Johnson, Joel E; Mienert, Jurgen; Plaza-Faverola, Andreia; Vadakkepuliyambatta, Sunil; Knies, Jochen; Bünz, Stefan; Andreassen, Karin; Ferré, Benedicte (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-05)
      Biotic gas generation from the degradation of organic carbon in marine sediments supplies and maintains gas hydrates throughout the world’s oceans. In nascent, ultraslow-spreading ocean basins, methane generation can also be abiotic, occurring during the high-temperature (>200 °C) serpentinization of ultramafic rocks. Here, we report on the evolution of a growing Arctic gas- and gas hydrate–charged ...
    • Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone 

      Singh, Asmita; Fietz, Susanne; Thomalla, Sandy J.; Sanchez, Nicolas; Ardelan, Murat V.; Moreau, Sebastian; Kauko, Hanna Maria; Fransson, Agneta; Chierici, Melissa; Samanta, Saumik; Mtshali, Thato N.; Roychoudhury, Alakendra N.; Ryan-Keogh, Thomas J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-31)
      he high nutrient–low chlorophyll condition of the Southern Ocean is generally thought to be caused by the low bioavailability of micronutrients, particularly iron, which plays an integral role in phytoplankton photosynthesis. Nevertheless, the Southern Ocean experiences seasonal blooms that generally initiate in austral spring, peak in summer, and extend into autumn. This seasonal increase in primary ...
    • Acoustic generation of underwater cavities - Comparing modeled and measured acoustic signals generated by seismic air gun arrays 

      Khodabandeloo, Babak; Landrø, Martin; Hanssen, Alfred (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-14)
      Underwater vapor cavities can be generated by acoustic stimulation. When the acoustic signals from several air guns are reflected from the sea surface, the pressure drop at some locations is sufficient for cavity growth and subsequent collapse. In this paper the generation of multiple water vapor cavities and their collapses are numerically modeled and the results are validated by comparing with ...
    • Active Nordic Seas deep-water formation during the last glacial maximum 

      Larkin, Christina S.; Mohamed, Mohamed Mahmoud Ezat Ahmed; Roberts, Natalie L.; Bauch, Henning A.; Spielhagen, Robert F.; Noormets, Riko; Polyak, Leonid; Moreton, Steven G.; Rasmussen, Tine Lander; Sarnthein, Michael; Tipper, Edward T.; Piotrowski, Alex M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-24)
      The Nordic Seas are the primary location where the warm waters of the North Atlantic Current densify to form North Atlantic Deep Water, which plays a key part in the modern Atlantic Meridional Overturning Circulation. The formation of dense water in the Nordic Seas and Arctic Ocean and resulting ocean circulation changes were probably driven by and contributed to the regional and global climate of ...
    • Adamastor – an ocean that never existed? 

      Konopasek, Jiri; Cavalcante, Carolina; Fossen, Haakon; Janoušek, Vojtěch (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-08)
      <p>Existing models of tectonic evolution of the Neoproterozoic orogenic system rimming the shores of the South Atlantic Ocean (the Araçuaí–Ribeira–Congo and Dom Feliciano–Kaoko–Gariep belts) interpret the belts as subduction-related orogens and emphasize the role of the “Adamastor Ocean” in their pre-collisional evolution. A critical problem in such an interpretation is the confined nature of the ...
    • Advances in understanding subglacial meltwater drainage from past ice sheets 

      Simkins, Lauren M; Greenwood, Sarah L.; Winsborrow, Monica; Bjarnadóttir, Lilja Rún; Lepp, Allison (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-17)
      Meltwater drainage beneath ice sheets is a fundamental consideration for understanding ice–bed conditions and bed-modulated ice flow, with potential impacts on terminus behavior and iceshelf mass balance. While contemporary observations reveal the presence of basal water movement in the subglacial environment and inferred styles of drainage, the geological record of former ice sheets, including ...
    • Aligned glaciotectonic rafts on the central Barents Sea seafloor revealing extensive glacitectonic erosion during the last deglaciation 

      Ruther, Denise Christina; Andreassen, Karin; Spagnolo, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-12-07)
      Erosion rates on glaciated continental shelves are remarkably high, especially within ice stream troughs. Although glaciotectonic erosion may have considerably contributed to enhanced glacial erosion of these landscapes, entrainment mechanisms of glaciotectonically emplaced megablocks and rafts remain little understood. Here we report a northeast-southwest trending chain of over 1300 glacial rafts, ...
    • Amino acid racemization in Quaternary foraminifera from the Yermak Plateau, Arctic Ocean 

      West, Gabriel; Kaufman, Darrell S; Muschitiello, Francesco; Forwick, Matthias; Matthiessen, Jens; Wollenburg, Jutta; O’Regan, Matt (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-18)
      Amino acid racemization (AAR) geochronology is a powerful tool for dating Quaternary marine sediments across the globe, yet its application to Arctic Ocean sediments has been limited. Anomalous rates of AAR in foraminifera from the central Arctic were reported in previously published studies, indicating that either the rate of racemization is higher in this area, or inaccurate age models were used ...
    • Ammonium and Sulfate Assimilation Is Widespread in Benthic Foraminifera 

      LeKieffre, Charlotte; Jauffrais, Thierry; Bernhard, Joan M.; Filipsson, Helena L.; Schmidt, Christiane; Roberge, Helene; Maire, Olivier; Panieri, Giuliana; Geslin, Emmanuelle; Meibom, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-20)
      Nitrogen and sulfur are key elements in the biogeochemical cycles of marine ecosystems to which benthic foraminifera contribute significantly. Yet, cell-specific assimilation of ammonium, nitrate and sulfate by these protists is poorly characterized and understood across their wide range of species-specific trophic strategies. For example, detailed knowledge about ammonium and sulfate assimilation ...
    • Amorphous material in experimentally deformed mafic rock and its temperature dependence: Implications for fault rheology during aseismic creep and seismic rupture 

      Marti, Sina; Stünitz, Holger; Heilbronner, Renee; Plümper, Oliver (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-20)
      Amorphous materials are frequently observed in natural and experimentally produced fault rocks. Their common occurrence suggests that amorphous materials are of importance to fault zone dynamics. However, little is known about the physico-chemical impact of amorphous materials on fault rheology. Here we present deformation experiments on mafic fault rock, where amorphous material forms due to intense ...
    • Analyse av mesozoiske forkastninger og asymmetriske landskap i et profil over Lofotryggen ved Leknes, Vestvågøy. Implikasjoner for dannelsen av roterte forkastningsblokker, riftrelaterte bassenger og nedforkastningen av Leknesgruppen 

      Haraldsvik, Kristian Liland (Master thesis; Mastergradsoppgave, 2015-07-15)
      Dette studiet fokuserer på asymmetriske landskap og deres relasjon til sprø forkastninger, bassenger og roterte forkastningsblokker i et profil over Lofotryggen ved Leknes. Det anvendte datasettet består av sammensatte data fra feltarbeid og landskapsobservasjoner, batymatriske kart og seismiske profiler fra kontinentalsokkelen i Lofoten og Vesterålen. Lofotryggen er definert av to prominente NØ-SV ...
    • Analyse av paleozoiske forkastninger og deres relasjon til devon-karbon avsetninger langs Sassenfjorden og Tempelfjorden, Svalbard, basert på multiverktøy land og fjord-datasett. 

      Nergård, Alf Petter (Master thesis; Mastergradsoppgave, 2020-09-02)
      Ledd i Billefjordforkastningssonen kan man finne på begge sidene av Sassenfjorden. Disse leddene er forsøkt knyttet sammen i denne analysen. Batymetriske data fra Sassenfjordens fjordbunn avslører rygger og andre strukturer som har en spennende innvirkning på de seismiske dataene. Hovedfunnene i denne analysen er kategorisert i tre kategorier. Kategori 1 omtaler en obskur sone på seismikken som ...
    • Analyse av strukturer og bevegelsesdata i det ustabile fjellskredområdet Gámmanjunni 3, Kåfjord kommune, Troms og Finnmark fylke. Med vekt på kontrollerende faktorer, skråningsprosesser, bevegelsesdynamikk og skredmodeller. 

      Hansen, Anne-Marte (Master thesis; Mastergradsoppgave, 2020-05-15)
      Gámanjunni 3 er et av de ustabile fjellpartiene i Norge med høyest bevegelseshastighet. Hovedmålet med studiet er å sammenstille gamle og nye feltdata, bevegelsesdata og geofysiske data fra tidligere studier ved Gámanjunni 3 til en helhetlig geologisk modell i 3D, og undersøke hvilke interne og eksterne faktorer som kontrollerer fjellpartiet. I tillegg skal det fokuseres på bevegelsesdynamikk, ...
    • Analyses of Paleozoic and Mesozoic brittle fractures in West-Finnmark. Geometry, kinematics and relations to structures on the Finnmark Platform in the southwestern Barents Sea 

      Bergø, Espen (Master thesis; Mastergradsoppgave, 2016-06-12)
      This study focuses on Paleozoic and Mesozoic brittle faults and fractures found onshore and offshore in the northwestern areas of Finnmark, the Finnmark Platform, and the southwestern Barents Sea Margin. These structures have been mapped using software for mapping (ArcGIS 10.5 & Petrel 2013) and analyzing fault-fracture lineaments and faults from bathymetry, digital elevation models, satellite images, ...
    • Analysis of Late Paleozoic-Mesozoic brittle faults and fractures in West-Finnmark: geometry, kinematics, fault rocks and the relationship to offshore structures on the Finnmark Platform in the SW Barents Sea 

      Lea, Halldis (Master thesis; Mastergradsoppgave, 2016-05-29)
      The present work focuses on the onshore/offshore analysis and correlation of brittle faults and fractures on the Porsanger Peninsula area in west-Finnmark, the shelf areas and the immidiate offshore areas (Finnmark Platform and Gjesvær low). Structural field observation, microstructural and SEM analysis provide the basis for the characterization of the geometry, kinematics and fault rocks. This data ...
    • An annual profile of the impacts of simulated oil spills on the Northeast Arctic cod and haddock fisherie 

      Carroll, JoLynn; Frøysa, Håvard Guldbrandsen; Vikebø, Frode Bendiksen; Broch, Ole Jacob; Nepstad, Raymond; Augustine, Starrlight; Skeie, Geir Morten; Bockwoldt, Mathias; Howell, Daniel (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-10)
      We simulate the combined natural and pollutant-induced survival of early life stages of NEA cod and haddock, and the impact on the adult populations in response to the time of a major oil spill in a single year. Our simulations reveal how dynamic ocean processes, controlling both oil transport and fate and the frequency of interactions of oil with drifting fish eggs and larvae, mediate the magnitude ...
    • An annual profile of the impacts of simulated oil spills on the Northeast Arctic cod and haddock fisheries 

      Carroll, JoLynn; Frøysa, Håvard Guldbrandsen; Vikebø, Frode Bendiksen; Broch, Ole Jacob; Howell, Daniel; Nepstad, Raymond; Augustine, Starrlight; Skeie, Geir Morten; Bockwoldt, Mathias (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-10)
      We simulate the combined natural and pollutant-induced survival of early life stages of NEA cod and haddock, and the impact on the adult populations in response to the time of a major oil spill in a single year. Our simulations reveal how dynamic ocean processes, controlling both oil transport and fate and the frequency of interactions of oil with drifting fish eggs and larvae, mediate the magnitude ...
    • Anthropocene rockfalls travel farther than prehistoric predecessors 

      Vick, Louise Mary; Borella, Josh Walter; Quigley, Mark (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-02)
      Human modification of natural landscapes has influenced surface processes in many settings on Earth. Quantitative data comparing the distribution and behavior of geologic phenomena before and after human arrival are sparse but urgently required to evaluate possible anthropogenic influences on geologic hazards. We conduct field and imagery-based mapping, statistical analysis, and numerical modeling ...
    • Anticlockwise metamorphic pressure–temperature paths and nappe stacking in the Reisa Nappe Complex in the Scandinavian Caledonides, northern Norway: evidence for weakening of lower continental crust before and during continental collision 

      Faber, Carly; Stunitz, Holger; Gasser, Deta; Jeřábek, Petr; Kraus, Katrin; Corfu, Fernando; Ravna, Erling Krogh; Konopásek, Jiří (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      This study investigates the tectonostratigraphy and metamorphic and tectonic evolution of the Caledonian Reisa Nappe Complex (RNC; from bottom to top: Vaddas, Kåfjord, and Nordmannvik nappes) in northern Troms, Norway. Structural data, phase equilibrium modelling, and U-Pb zircon and titanite geochronology are used to constrain the timing and pressure–temperature (<i>P–T</i>) conditions of deformation ...
    • Arc-like magmatism in syn- to post-collisional setting: The Ediacaran Angra Fria Magmatic Complex (NW Namibia) and its cross-Atlantic correlatives in the south Brazilian Florianópolis Batholith 

      Janousek, Vojtěch; Florisbal, Luana Moreira; Konopásek, Jiří; Jeřábek, Petr; Bitencourt, Maria de Fatima; Gadas, Petr; Erban, Vojtěch; Kopačková-Strnadová, Veronika (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-27)
      Ediacaran syn-tectonic plutonic rocks (amphibole gabbros, quartz diorites/tonalites to biotite- and muscovite-bearing granites) of the Angra Fria Magmatic Complex (Kaoko Belt, north-western Namibia) belong to two compositionally similar, magnesian, transitional tholeiitic–calc-alkaline suites, the Older (∼625–620 Ma) and the Younger (∼585–575 Ma). Both have counterparts in the broadly contemporaneous ...