Viser treff 203-222 av 711

    • Experimental grain growth of quartz aggregates under wet conditions and its application to deformation in nature 

      Fukuda, Junichi; Raimbourg, Hugues; Shimizu, Ichiko; Neufeld, Kai; Stünitz, Holger (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-13)
      Grain growth of quartz was investigated using two quartz samples (powder and novaculite) with water under pressure and temperature conditions of 1.0–2.5 GPa and 800–1100 ∘C. The compacted powder preserved a substantial porosity, which caused a slower grain growth than in the novaculite. We assumed a grain growth law of <i>d<sup>n</sup>−d<sup>n</sup><sub>0</sub>=k</i><sub>0</sub><i>f<sup>r</sup><su ...
    • Experimental investigation of the brittle-viscous transition in mafic rocks – Interplay between fracturing, reaction, and viscous deformation 

      Marti, Sina; Stunitz, Holger; Heilbronner, Renée; Drury, Martyn; Plümper, Oliver; Drury, Martyn (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-03)
      Rock deformation experiments are performed on fault gouge fabricated from ‘Maryland Diabase’ rock powder to investigate the transition from dominant brittle to dominant viscous behaviour. At the imposed strain rates of γ = 3 • 10⁻⁵ − 3 • 10⁻⁶ s-1 the transition is observed in the temperature range of (600 °C < T < 800 °C) at confining pressures of (0.5 GPa ≤ Pc ≤ 1.5 GPa). The transition thereby ...
    • Exploring late Pleistocene bioturbation on Yermak Plateau to assess sea-ice conditions and primary productivity through the Ethological Ichno Quotient 

      Singh, Akanksha; O’Regan, Matt; Coxall, Helen K.; Forwick, Matthias; Löwemark, Ludvig (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-13)
      Central Arctic, interglacial intervals have traditionally been associated with diverse and intense bioturbation, and abundant foraminifera, interpreted as indicating relatively low sea-ice concentrations and productive surface waters, while glacial intervals, typically barren, support the inverse. In this respect, the Yermak Plateau is anomalous. Biomarker studies suggest that glacial intervals were ...
    • Exploring the teaching environment in a higher education geoscience programme 

      Malm, Rie Hjørnegaard; Martens, Iver (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-19)
      This paper explores the teaching environment among the teaching staff in thegeoscience programme at UiT The Arctic University of Norway. The findings in this paper are based on a large baseline study conducted in 2018. This paper operationalises the teaching culture by analysing the teachers’ ideas, collaborations, and attitudes towards teaching. In-depth interviews ...
    • Extensive release of methane from Arctic seabed west of Svalbard during summer 2014 does not influence the atmosphere 

      Myhre, Cathrine Lund; Ferré, Benedicte; Platt, Stephen Matthew; Silyakova, Anna; Hermansen, Ove; Allen, Grant; Pisso, Ignacio; Schmidbauer, Josef Norbert; Stohl, Andreas; Pitt, Joseph R.; Jansson, Pær; Greinert, Jens; Percival, Carl; Fjæraa, Ann Mari; O'Shea, Sebastian J.; Gallagher, Martin; Le Breton, Michael; Bower, Keith N.; Bauguitte, Stéphane Jean-Bernard; Dalsøren, Stig Bjørløw; Vadakkepuliyambatta, Sunil; Fisher, Rebecca E.; Nisbet, Euan G.; Lowry, David; Myhre, Gunnar; Pyle, John Adrian; Cain, Michelle; Mienert, Jurgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-07)
      We find that summer methane (CH4) release from seabed sediments west of Svalbard substantially increases CH4 concentrations in the ocean but has limited influence on the atmospheric CH4 levels. Our conclusion stems from complementary measurements at the seafloor, in the ocean, and in the atmosphere from land-based, ship and aircraft platforms during a summer campaign in 2014. We detected high ...
    • Extraordinary runoff from the Greenland ice sheet in 2012 amplified by hypsometry and depleted firn retention 

      Mikkelsen, A.B.; Hubbard, Alun Lloyd; MacFerrin, Mike; Box, Jason Eric; Doyle, Sam H.; Fitzpatrick, Andrew; Hasholt, Bent; Bailey, Hannah L.; Lindbäck, Katrin; Pettersson, Rickard (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-30)
      It has been argued that the infiltration and retention of meltwater within firn across the percolation zone of the Greenland ice sheet has the potential to buffer up to  ∼  3.6 mm of global sea-level rise (Harper et al., 2012). Despite evidence confirming active refreezing processes above the equilibrium line, their impact on runoff and proglacial discharge has yet to be assessed. Here, we compare ...
    • The extreme yet transient nature of glacial erosion 

      Patton, Henry; Hubbard, Alun; Heyman, J.; Alexandropoulou, Nikolitsa; Lasabuda, Amando P. E.; Stroeven, A.P.; Hall, A.M.; Winsborrow, Monica; Sugden, David E.; Kleman, J.; Andreassen, Karin Marie (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-30)
      Ice can sculpt extraordinary landscapes, yet the efficacy of, and controls governing, glacial erosion on geological timescales remain poorly understood and contended, particularly across Polar continental shields. Here, we assimilate geophysical data with modelling of the Eurasian Ice Sheet — the third largest Quaternary ice mass that spanned 49°N to 82°N — to decipher its erosional footprint during ...
    • Factors controlling the net ecosystem production of cryoconite on Western Himalayan glaciers 

      Shamurailatpam, Monica S.; Telling, Jon; Wadham, Jemma Louise; Ramanathan, A. L.; Yates, Christopher A.; Raju, N. Janardhana (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-07)
      In situ experiments were conducted to determine the net ecosystem production (NEP) in cryoconite holes from the surface of two glaciers (Patsio glacier and Chhota Shigri glacier) in the Western Himalaya during the melt season from August to September 2019. The study aimed to gain an insight into the factors controlling microbial activity on glacier surfaces in this region. A wide range of parameters, ...
    • Fast and slow components of interstadial warming in the North Atlantic during the last glacial 

      Margari, Vasiliki; Skinner, Luke C.; Menviel, Laurie; Capron, Emilie; Rhodes, Rachael H; Mleneck-Vautravers, Maryline J.; Ezat, Mohamed; Martrat, Belen; Grimalt, Joan O.; Hodell, David A; Tzedakis, Polychronis (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-13)
      The abrupt nature of warming events recorded in Greenland ice-cores during the last glacial has generated much debate over their underlying mechanisms. Here, we present joint marine and terrestrial analyses from the Portuguese Margin, showing a succession of cold stadials and warm interstadials over the interval 35–57 ka. Heinrich stadials 4 and 5 contain considerable structure, with a short ...
    • The fate of plastic in the ocean environment – a minireview 

      Wayman, Chloe; Niemann, Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-14)
      The presence of plastics in the marine environment poses a threat to ocean life and has received much scientific and public attention in recent years. Plastics were introduced to the market in the 1950s and since then, global production figures and ocean plastic littering have increased exponentially. Of the 359 million tonnes (Mt) produced in 2018, an estimated 14.5 Mt has entered the ocean. In ...
    • Fault-controlled asymmetric landscapes and low-relief surfaces on Vestvågøya, Lofoten, North Norway: inherited Mesozoic rift-margin structures? 

      Bergh, Steffen G; Liland, Kristian; Corner, Geoffrey D.; Henningsen, Tormod; Lundekvam, Petter (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-20)
      The Lofoten Ridge is an integral basement horst of the hyperextended continental rift-margin off northern Norway. It is a key area for studying onshore–offshore rift-related faults, and for evaluating tectonic control on landscape development along the North Atlantic margin. This paper combines onshore geomorphological relief/aspect data and fault/fracture analysis with offshore bathymetric and ...
    • Fault-controlled fluid circulation and diagenesis along basin-bounding fault systems in rifts - Insights from the East Greenland rift system 

      Salomon, Eric; Rotevatn, Atle; Kristensen, Thomas Berg; Grundvåg, Sten-Andreas; Henstra, Gijs Allard; Meckler, Anna Nele; Albert, Richard; Gerdes, Axel (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-05)
      In marine rift basins, deep-water clastics (>200 m) in the hanging wall of rift- or basin-bounding fault systems are commonly juxtaposed against crystalline “basement” rocks in the footwall. A distinct feature of such fault systems is therefore the juxtaposition of relatively highly permeable, unconsolidated sediments against relatively low-permeable basement rocks. Due to limited surface exposure ...
    • Feasibility of using the P-Cable high-resolution 3D seismic system in detecting and monitoring CO2 leakage 

      Waage, Malin; Singhroha, Sunny; Bünz, Stefan; Planke, Sverre; Waghorn, Kate Alyse; Bellwald, Benjamin (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-23)
      The P-Cable technology is an acquisition principle for high-resolution and ultra-high-resolution 3D seismic data. Many 3D seismic datasets have been acquired over the last decade, but the application in time-lapse studies for monitoring of CO2 storage is a new and intriguing topic. High-resolution 3D (HR3D) seismic has the potential to detect and monitor CO2 leakage at carbon capture and storage ...
    • The First International Conference on 'Processes and Palaeo-Environmental Changes in the Arctic: From Past to Present' (PalaeoArc) 

      Lyså, Astrid; Benediktsson, Ívar Örn; Emery, Andy; Gregoire, Lauren; Jennings, Anne; Morigi, Caterina; Müller, Juliane; O'Regan, Matt; Sarala, Pertti; Stokes, Chris; Szczuciński, Witold; Winsborrow, Monica (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-13)
      The new international network PalaeoArc (Processes and Palaeo Environmental Changes in the Arctic: From Past to Present) held its first meeting in Poznan, 20-24 May 2019. The meeting was hosted by the Faculty of Geographical and Geological Sciences, Adam Mickiewicz University, Poznan, and organized by a local committee chaired by Witold Szczuciński.
    • First record of catacrinid crinoid from the Lower Permian of Spitsbergen 

      Gorzelak, Przemyslaw; Blazejowski, Blazej; Uchman, Alfred; Hanken, Nils-Martin (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      An early Permian (late Artinskian–Roadian) cladid crinoid (Catacrinidae gen. et sp. indet.) is reported for the first time from the Vøringen Member of the Kapp Starostin Formation of Spitsbergen. The specimen is partly articulated and preserves a considerable part of its stalk and a complete cup, but only the proximal portions of its arms. Thus, it can− not be identified with any degree of ...
    • A flexural isostasy model for the Pleistocene evolution of the Barents Sea bathymetry 

      Zieba, Krzysztof Jan; Omosanya, Kamaldeen Olakunle; Knies, Jochen (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-24)
      The topographic relief of the Barents Sea was subjected to major changes during the past 1.5 million years mostly due to sediment redistribution driven by glacial activity. This paper addresses the problem of Pleistocene bathymetric evolution of the southern Barents Sea using a numerical modelling approach that considers the influence of regional isostasy on relief development. The model presented ...
    • Fluid flow and methane occurrences in the Disko Bugt area offshore West Greenland: indications for gas hydrates? 

      Nielsen, Tove; Laier, Troels; Kuijpers, Antoon; Rasmussen, Tine Lander; Mikkelsen, Naja E.; Nørgård-Pedersen, Niels (Journal article; Tidsskriftartikkel, 2014-09-04)
      The present study is the first to directly address the issue of gas hydrates offshore West Greenland, where numerous occurrences of shallow hydrocarbons have been documented in the vicinity of Disko Bugt (Bay). Furthermore, decomposing gas hydrate has been implied to explain seabed features in this climate-sensitive area. The study is based on archive data and new (2011, 2012) shallow seismic and ...
    • Food/feed and environmental risk assessment of genetically modified glufosinate-tolerant oilseed rape MS8, RF3 and MS8 x RF3 for import, processing and feed uses under Directive 2001/18/EC (Notification C/BE/96/01) 

      Andreassen, Åshild Kristine; Brandtzæg, Per; Finne, Merethe Aasmo; Holck, Askild Lorentz; Jevnaker, Anne Marthe; Junttila, Juho; Konestabo, Heidi Sjursen; Meadow, Richard; Mikalsen, Arne; Nielsen, Kaare Magne; Sipinen, Ville Erling; Sorteberg, Hilde-Gunn Opsahl; Vikse, Rose (Research report; Forskningsrapport, 2014-03-28)
      In preparation for a legal implementation of EU-regulation 1829/2003, the Norwegian Environment Agency (former Norwegian Directorate for Nature Management) has requested the Norwegian Food Safety Authority (NFSA) to give final opinions on all genetically modified organisms (GMOs) and products containing or consisting of GMOs that are authorized in the European Union ...
    • Foraminiferal δ18O reveals gas hydrate dissociation in Arctic and North Atlantic ocean sediments 

      Dessandier, Pierre-Antoine; Borrelli, Chiara; Yao, Haoyi; Sauer, Simone; Hong, Wei-Li; Panieri, Giuliana (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-07)
      Paleoceanographic investigations in the Arctic and north Atlantic are crucial to understanding past and current climate change, in particular considering amounts of pressure-temperature sensitive gas stored in marine sediments of the region. Many paleoceanographic studies are based on foraminiferal oxygen and carbon stable isotope compositions (δ<sup>18</sup>O, δ<sup>13</sup>C) from either planktonic ...
    • Foreløpig helse- og miljørisikovurdering av genmodifisert maislinje Event 5307 fra Syngenta Crop Protection AG (EFSA/GMO/DE/2011/95) 

      Nerland, Audun Helge; Brandtzæg, Per; Finne, Merethe Aasmo; Holck, Askild Lorentz; Junttila, Juho; Konestabo, Heidi Sjursen; Meadow, Richard; Mikalsen, Arne; Nielsen, Kaare Magne; Sorteberg, Hilde-Gunn Opsahl; Sanden, Monica; Andreassen, Åshild Kristine; Vikse, Rose; Bernhoft, Aksel (Research report; Forskningsrapport, 2011-11-25)
      Den foreløpige helse- og miljørisikovurderingen av insektresistent maislinje 5307 (EFSA/GMO/DE/2011/95) fra Syngenta Crop Protection AG er utført av Faggruppe for genmodifiserte organismer i Vitenskapskomiteen for mattrygghet (VKM). Vitenskapskomiteen for mattrygghet er bedt av Mattilsynet og Direktoratet for naturforvalting ...