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  • The configuration, sensitivity and rapid retreat of the Late Weichselian Icelandic ice sheet 

    Patton, Henry; Hubbard, Alun Lloyd; Bradwell, T.; Schomacker, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-03)
    The fragmentary glacial-geological record across the Icelandic continental shelf has hampered reconstruction of the volume, extent and chronology of the Late Weichselian ice sheet particularly in key offshore zones. Marine geophysical data collected over the last two decades reveal that the ice sheet likely attained a continental shelf-break position in all sectors during the Last Glacial Maximum, ...
  • A Theoretical Model of Drumlin Formation Based on Observations at Múlajökull, Iceland 

    Iverson, N. R.; McCracken, R. G.; Zoet, L. K.; Benediktsson, Í. Ö.; Schomacker, Anders; Johnson, M. D.; Woodard, J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-20)
    The drumlin field at the surge‐type glacier, Múlajökull, provides an unusual opportunity to build a model of drumlin formation based on field observations in a modern drumlin‐forming environment. These observations indicate that surges deposit till layers that drape the glacier forefield, conform to drumlin surfaces, and are deposited in shear. Observations also indicate that erosion helps create ...
  • Structural glaciology of Isunguata Sermia, West Greenland 

    Jones, Christine; Ryan, Jonathan; Holt, Tom; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-26)
    We present a 1:42,000 scale map of Isunguata Sermia, a land-terminating outlet glacier draining the western-sector of the Greenland Ice Sheet. Structure-from-Motion software applied to ∼3,600 aerial images collected by a fixed-wing unmanned aerial vehicle in July 2015 allowed us to produce a high resolution (0.3 m ground sampling distance (GSD)) orthomosaic and digital elevation model (DEM; 1.5 m ...
  • BedMachine v3: Complete bed topography and ocean bathymetry mapping of Greenland from multi-beam echo sounding combined with mass conservation 

    Morlighem, Mathieu; Williams, Chris N.; Rignot, Eric J.M.; An, Lu; Arndt, Jan Erik; Bamber, Jonathan L.; Catania, Ginny A.; Chauché, Nolwenn; Dowdeswell, Julian A.; Dorschel, Boris; Fenty, Ian; Hogan, Kelly A.; Howat, Ian M.; Hubbard, Alun Lloyd; Jakobsson, Martin; Jordan, Thomas M.; Kjeldsen, Kristian Kjellerup; Millan, Romain; Mayer, Larry; Mouginot, Jérémie; Noël, Brice P.Y.; O'Cofaigh, Colm; Palmer, Steven; Rysgaard, Søren; Seroussi, Hélène; Siegert, Martin J.; Slabon, Patricia; Straneo, Fiamma; van den Broeke, Michiel R.; Weinrebe, Wilhelm Reimer; Wood, Michael; Zinglersen, Karl Brix (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-18)
    Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic water (AW) that rapidly melts and undercuts Greenland's marine‐terminating glaciers. Here we present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness ...
  • Direct measurements of meltwater runoff on the Greenland ice sheet surface 

    Smith, Laurence C.; Yang, Kang; Pitcher, Lincoln H.; Overstreet, Brandon T.; Chu, Vena W.; Rennermalm, Åsa K.; Ryan, Jonathan C.; Cooper, Matthew G.; Gleason, Colin J.; Tedesco, Marco; Jeyaratnam, Jeyavinoth; van As, Dirk; van den Broeke, Michiel R.; van de Berg, Willem Jan; Noël, Brice; Langen, Peter L.; Cullather, Richard I.; Zhao, Bin; Willis, Michael J.; Hubbard, Alun Lloyd; Box, Jason E.; Jenner, Brittany A.; Behar, Alberto E. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-05)
    Meltwater runoff from the Greenland ice sheet surface influences surface mass balance (SMB), ice dynamics, and global sea level rise, but is estimated with climate models and thus difficult to validate. We present a way to measure ice surface runoff directly, from hourly in situ supraglacial river discharge measurements and simultaneous high-resolution satellite/drone remote sensing of upstream ...
  • Late Pliocene–early Pleistocene deep-sea basin sedimentation at high-latitudes: mega-scale submarine slides of the north-western Barents Sea margin prior to the shelf-edge glaciations 

    Safronova, Polina; Laberg, Jan Sverre; Andreassen, Karin; Shlykova, V.; Vorren, Tore Ola; Chernikov, S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-01)
    At high‐latitude continental margins, large‐scale submarine sliding has been an important process for deep‐sea sediment transfer during glacial and interglacial periods. Little is, however, known about the importance of this process prior to the arrival of the ice sheet on the continental shelf. Based on new two‐dimensional seismic data from the NW Barents Sea continental margin, this study documents ...
  • 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, ...
  • Energy barriers in three-dimensional micromagnetic models and the physics of thermoviscous magnetization 

    Fabian, Karl; Shcherbakov, Valera P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-17)
    A first-principle micromagnetic and statistical calculation of viscous remanent magnetization (VRM) in an ensemble of cubic magnetite pseudo-single domain (PSD) particles is presented. The theoretical methods developed apply to all magnetic particle sizes, from single domain to multidomain. The numerical implementation is based on a fast relaxation algorithm for finding optimal transition paths ...
  • Cohesive and mixed sediment in the Regional Ocean Modeling System (ROMS v3.6) implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST r1234) 

    Sherwood, Christopher R.; Aretxabaleta, Alfredo L.; Harris, Courtney K.; Rinehimer, J. Paul; Verney, Romaric; Ferré, Benedicte (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-14)
    We describe and demonstrate algorithms for treating cohesive and mixed sediment that have been added to the Regional Ocean Modeling System (ROMS version 3.6), as implemented in the Coupled Ocean–Atmosphere–Wave– Sediment Transport Modeling System (COAWST Subversion repository revision 1234). These include the following: floc dynamics (aggregation and disaggregation in the water column); changes in ...
  • Resolving the internal and basal geometry of ice masses using imaging phase-sensitive radar 

    Young, Tun Jan; Schroeder, Dustin M.; Christoffersen, Poul; Lok, Lai B.; Nicholls, Keith W.; Brennan, Paul V.; Doyle, Samuel H.; Hubbard, Bryn; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-19)
    The phase-sensitive radio-echo sounder (pRES) is a powerful new instrument that can measure the depth of internal layers and the glacier bed to millimetre accuracy. We use a stationary 16-antenna pRES array on Store Glacier in West Greenland to measure the three-dimensional orientation of dipping internal reflectors, extending the capabilities of pRES beyond conventional depth sounding. This novel ...
  • Physical Conditions of Fast Glacier Flow: 2. Variable Extent of Anisotropic Ice and Soft Basal Sediment From Seismic Reflection Data Acquired on Store Glacier, West Greenland 

    Hofstede, C.; Christoffersen, P.; Hubbard, B.; Doyle, S.H.; Young, T.J.; Diez, A.; Eisen, O.; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-09)
    Outlet glaciers of the Greenland Ice Sheet transport ice from the interior to the ocean and contribute directly to sea level rise because discharge and ablation often exceed the accumulation. To develop a better understanding of these fast‐flowing glaciers, we investigate the basal conditions of Store Glacier, a large outlet glacier flowing into Uummannaq Fjord in west Greenland. We use two crossing ...
  • Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland 

    Doyle, S. H.; Hubbard, B.; Christoffersen, P.; Young, T.J.; Hofstede, C; Bougamont, M.; Box, J.E.; Hubbard, A.L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-21)
    Marine‐terminating outlet glaciers of the Greenland Ice Sheet make significant contributions to global sea level rise, yet the conditions that facilitate their fast flow remain poorly constrained owing to a paucity of data. We drilled and instrumented seven boreholes on Store Glacier, Greenland, to monitor subglacial water pressure, temperature, electrical conductivity, and turbidity along with ...
  • Monitoring marine mammals using unmanned aerial vehicles: quantifying detection certainty 

    Aniceto, Ana Sofia; Biuw, Martin; Lindstrøm, Ulf; Solbø, Stian; Broms, Fredrik Björn; Carroll, JoLynn (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-08)
    Unmanned aerial vehicles (UAVs) are increasingly being recognized as potentially useful for detection of marine mammals in their natural habitats, but an important consideration is the associated uncertainties in animal detection. We present a study based on field trials using UAVs to carry out image‐based monitoring of cetaceans in two fjords in northern Norway. We conducted 12 missions to assess ...
  • High-resolution 3D seismic study of pockmarks and shallow fluid flow systems at the Snøhvit hydrocarbon field in the SW Barents Sea 

    Tasianas, Alexandros; Bünz, Stefan; Bellwald, Benjamin; Hammer, Øyvind; Planke, Sverre; Lebedeva-Ivanova, Nina; Krassakis, Pavlos (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-21)
    The Barents Sea is an epicontinental shelf sea with a fragmented structure consisting of long fault complexes, basins and basement highs. Fluid leakage from deep-seated hydrocarbon accumulations is a widespread phenomenon and mostly related to its denudation history during the glacial/interglacial cycles. In this study, we aimed to better understand shallow fluid flow processes that have led to the ...
  • Sea ice and primary production proxies in surface sediments from a High Arctic Greenland fjord: Spatial distribution and implications for palaeoenvironmental studies 

    Ribeiro, Sofia; Sejr, Mikael K.; Limoges, Audrey; Heikkilä, Maija; Andersen, Thorbjørn Joest; Tallberg, Petra; Weckström, Kaarina; Husum, Katrine; Forwick, Matthias; Dalsgaard, Tage; Massé, Guillaume; Seidenkrantz, Marit-Solveig; Rysgaard, Søren (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-23)
    In order to establish a baseline for proxy-based reconstructions for the Young Sound–Tyrolerfjord system (Northeast Greenland), we analysed the spatial distribution of primary production and sea ice proxies in surface sediments from the fjord, against monitoring data from the Greenland Ecosystem Monitoring Programme. Clear spatial gradients in organic carbon and biogenic silica contents reflected ...
  • Geophysical and geochemical controls on the megafaunal community of a high Arctic cold seep 

    Sen, Arunima; Åström, Emmelie Karin Linnea; Hong, Wei-Li; Portnov, Aleksei D; Waage, Malin; Serov, Pavel; Carroll, Michael Leslie; Carroll, JoLynn (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-25)
    Cold-seep megafaunal communities around gas hydrate mounds (pingos) in the western Barents Sea (76°N, 16°E,  ∼ 400 m depth) were investigated with high-resolution, geographically referenced images acquired with an ROV and towed camera. Four pingos associated with seabed methane release hosted diverse biological communities of mainly nonseep (background) species including commercially important fish ...
  • 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; Preprint; Manuskript, 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 ...
  • Neogene dinoflagellate cysts and acritarchs from the high northern latitudes and their relation to sea surface temperature 

    Schreck, Michael; Nam, Seung-Il; Clotten, Caroline; Fahl, Kirsten; De Schepper, Stijn; Forwick, Matthias; Matthiessen, Jens (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-13)
    <p>Organic-walled dinoflagellate cysts and acritarchs are a vital tool for reconstructing past environmental change, in particular in the Neogene of the high northern latitudes where marine deposits are virtually barren of traditionally used calcareous microfossils. Yet only little is known about the paleoenvironmental value of fossil assemblages that do not have modern analogues, so that reconstructions ...
  • Novel biomineralization strategy in calcareous foraminifera 

    Borrelli, Chiara; Panieri, Giuliana; Dahl, Trine Merete; Neufeld, Kai (Journal article; Tidsskriftartikkel; Peer reviewed, 2018)
    This work shows that calcareous benthic foraminifera are capable of agglutinating sedimentary particles also. In particular, we focus on Melonis barleeanus. Traditionally considered a calcareous species, our data revealed the presence of minute (~3 μm) sedimentary particles (silicate grains) inside the chamber walls of the examined shells. These particles were arranged in a definitive and systematic ...
  • Rheological Weakening of Olivine + Orthopyroxene Aggregates Due To Phase Mixing: Part 2. Microstructural Development 

    Tasaka, Miki; Zimmerman, Mark E; Kohlstedt, David L.; Stünitz, Holger; Heilbronner, Renée (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-08)
    To understand the processes involved in phase mixing during deformation and the resulting changes in rheological behavior, we conducted torsion experiments on samples of iron‐rich olivine plus orthopyroxene. The experiments were conducted at a temperature, T, of 1200°C and a confining pressure, P, of 300 MPa using a gas‐medium deformation apparatus. Samples composed of olivine plus 26% orthopyroxene ...

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