Viser treff 547-566 av 711

    • A refined late-Cryogenian – Ediacaran Earth history of South China: phosphorous-rich marbles of the Dabie and Sulu orogens 

      Prave, Anthony R; Meng, F.; Lepland, Aivo; Kirsimäe, Kalle; Kreitsmann, Timmu; Jiang, C.Z. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-02)
      The late-Cryogenian – Ediacaran geological framework for South China is constructed principally from sedimentary successions preserved in the central and western regions of the Yangtze Block. New stratigraphic and carbonate-carbon isotope data allow us to extend that framework into the exhumed HP-UHP subduction complexes of the eastern Dabie and Sulu orogens that separate the South and North China ...
    • Regional Morpho-Kinematic Inventory of Slope Movements in Northern Norway 

      Rouyet, Line; Lilleøren, Karianne Staalesen; Böhme, Martina; Vick, Louise Mary; Delaloye, Reynald; Etzelmüller, Bernd; Lauknes, Tom Rune; Larsen, Yngvar; Blikra, Lars Harald (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-25)
      Mountain slopes in periglacial environments are affected by frost- and gravity-driven processes that shape the landscape. Both rock glaciers and rockslides have been intensively inventoried worldwide. Although most inventories are traditionally based on morphologic criteria, kinematic approaches based on satellite remote sensing have more recently been used to identify moving landforms at the regional ...
    • Relating 3D surface displacement from satellite- and ground-based InSAR to structures and geomorphology of the Jettan rockslide, northern Norway 

      Eriksen, Harald Øverli; Bergh, Steffen G; Larsen, Yngvar; Skrede, Ingrid; Kristensen, Lene; Lauknes, Tom Rune; Blikra, Lars Harald; Kierulf, Halfdan Pascal (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-13)
      This study combines remote sensing data from ground- and satellite-based radar to calculate 3D displacement vectors for the Jettan rockslide, Troms, northern Norway. Using 3D displacement vectors, aspect data and strain rates in conjunction with structure (foliation, faults, fractures), geomorphological elements (ridges, scarps, terraces, depressions), topography and borehole data, we identify zones ...
    • Relationship between mega-scale glacial lineations and iceberg ploughmarks on the Bjørnøyrenna Palaeo-Ice Stream bed, Barents Sea 

      Andreassen, Karin; Piasecka, Emilia D.; Stokes, Chris R.; Winsborrow, Monica C.M. (Journal article; Tidsskriftartikkel, 2018-02-24)
      Mega-scale glacial lineations (MSGLs) are ridge-groove corrugations aligned in the direction of the former ice flow, tens of kilometers long and up to a few hundred meters wide. They are the most striking subglacial features on the beds of former ice streams and play an important role in modulating ice flow through their influence on bed roughness and subglacial hydrology. Despite the importance of ...
    • Relationship between microstructures and resistance in mafic assemblages that deform and transform 

      Mansard, Nicolas; Stunitz, Holger; Raimbourg, Hugues; Précigout, Jacques; Plunder, Alexis; Nègre, Lucille (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-18)
      Syn-kinematic mineral reactions play an important role for the mechanical properties of polymineralic rocks. Mineral reactions (i.e., nucleation of new phases) may lead to grain size reduction, producing fine-grained polymineralic mixtures, which have a strongly reduced viscosity because of the activation of grain-size-sensitive deformation processes. In order to study the effect of deformation–reaction ...
    • Removal of methane through hydrological, microbial, and geochemical processes in the shallow sediments of pockmarks along eastern Vestnesa Ridge (Svalbard) 

      Hong, Wei-Li; Sauer, Simone; Panieri, Giuliana; Ambrose, William; James, Rachel; Plaza-Faverola, Andreia; Schneider, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      The recent discovery of methane seeps in the Arctic region requires a better understanding of the fate of methane in marine sediments if we are to understand the contributions of methane to Arctic ecosystems and climate change. To further this goal, we analyze pore water data from five pockmarks along eastern Vestnesa Ridge, a sediment drift northwest of Svalbard, to quantify the consumption ...
    • Repeatability of high-resolution 3D seismic data 

      Waage, Malin; Bünz, Stefan; Landrø, Martin; Plaza-Faverola, Andreia; Waghorn, Kate Alyse (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-21)
      High-resolution 4D (HR4D) seismic data have the potential for improving the current state-of-the-art in detecting shallow (≤500−1000  m below seafloor) subsurface changes on a very fine scale (approximately 3–6 m). Time-lapse seismic investigations commonly use conventional broadband seismic data, considered low to moderate resolution in our context. We have developed the first comprehensive time ...
    • Reply to 'Challenges with dating weathering products to unravel ancient landscapes' 

      Fredin, Ola; Viola, Giulio; Zwingmann, Horst; Sørlie, Ronald; Brönner, Marco; Lie, Jan-Erik; Grandal, Else Margrethe; Müller, Axel; Margreth, Annina; Vogt, Christoph; Knies, Jochen (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-15)
      <i>Introduction</i>: As the title of the correspondence by Fossen et al.1 suggests, determining the age of landscape elements of the Earth surface is difficult. We thus welcome the opportunity to clarify our arguments on the contentious themes touched upon by Fredin et al.2 The age of landscapes has been a recurring research topic for the last century. Often, landscape ages can be deduced indirectly ...
    • Resistivity of reservoir sandstones and organic rich shales on the Barents Shelf: Implications for interpreting CSEM data 

      Senger, Kim; Birchall, Thomas; Betlem, Peter; Ogata, Kei; Ohm, Sverre Ekrene; Olaussen, Snorre; Paulsen, Renate Strugstad (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-03)
      Marine controlled source electromagnetic (CSEM) data have been utilized in the past decade during petroleum exploration of the Barents Shelf, particularly for de-risking the highly porous sandstone reservoirs of the Upper Triassic to Middle Jurassic Realgrunnen Subgroup. In this contribution we compare the resistivity response from CSEM data to resistivity from wireline logs in both water- and ...
    • 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 ...
    • Response of benthic foraminifera to environmental successions of cold seeps from Vestnesa Ridge, Svalbard: Implications for interpretations of paleo-seepage environments 

      Melaniuk, Katarzyna; Sztybor, Kamila; Treude, Tina; Sommer, Stefan; Zajaczkowski, Marek; Rasmussen, Tine Lander (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-15)
      This paper presents the results of a study on the response of living benthic foraminifera to progressing environmental successions in a cold-seep ecosystem. Sediment samples were collected from Vestnesa Ridge (79°N, Fram Strait) at ~1200 m water depth. The distribution of live (Rose Bengal-stained) foraminifera were analyzed in the upper sediment layers in relation to pore water biogeochemical data ...
    • The Response of Tidewater Glacier Termini Positions in Hornsund (Svalbard) to Climate Forcing, 1992–2020 

      Błaszczyk, Małgorzata; Moskalik, Mateusz; Grabiec, Mariusz; Jania, Jacek; Walczowski, Waldemar; Wawrzyniak, Tomasz; Strzelewicz, Agnieszka; Malnes, Eirik; Lauknes, Tom Rune; Pfeffer, W. Tad (Journal article; Tidsskriftartikkel, 2023-05-19)
      Many Arctic marine-terminating glaciers have undergone rapid retreats in recent decades. Seasonal and year-to-year variations in terminus position act on all tidewater glaciers, but the key controls on those changes vary from region to region. Here, we examined seasonal and decadal changes in termini positions of seven tidewater glaciers in the inner part of Hornsund, the southernmost fjord of ...
    • Response time correction of slow-response sensor data by deconvolution of the growth-law equation 

      Dølven, Knut Ola; Vierinen, Juha; Grilli, Roberto; Triest, Jack; Ferré, Benedicte (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-11)
      Accurate high-resolution measurements are essential to improve our understanding of environmental processes. Several chemical sensors relying on membrane separation extraction techniques have slow response times due to a dependence on equilibrium partitioning across the membrane separating the measured medium (i.e., a measuring chamber) and the medium of interest (i.e., a solvent). We present a new ...
    • Retreat patterns and dynamics of the former Norske Trough ice stream (NE Greenland): An integrated geomorphological and sedimentological approach 

      López-Quirós, Adrián; Junna, Tuomas; Davies, Joanna; Andresen, Katrine J.; Nielsen, Tove; Haghipour, Negar; Wacker, Lukas; Alstrup, Aage Kristian Olsen; Munk, Ole Lajord; Rasmussen, Tine Lander; Pearce, Christof; Seidenkrantz, Marit Solveig (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-09)
      A better understanding of past extent and dynamics of the Greenland Ice Sheet (GrIS) is required to provide context for present-day observations, to constrain numerical climate models and to predict future scenarios of ice-sheet response to recent climatic change. The presence of a grounded GrIS on the NE Greenland shelf during the Last Glacial Maximum (LGM) is supported by high-resolution seismic ...
    • Retreat patterns and dynamics of the Sentralbankrenna glacial system, central Barents Sea 

      Esteves, Mariana da Silveira Ramos; Bjarnadóttir, Lilja Rún; Winsborrow, Monica; Shackleton, Calvin; Andreassen, Karin (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-26)
      The Barents Sea Ice Sheet (BSIS) is a good palaeo-analogue for the present day West Antarctic Ice Sheet. Both were marine-based ice sheets, particularly vulnerable to ocean warming and sea-level rise. Understanding the BSIS ice dynamics and patterns of retreat since the Last Glacial Maximum (LGM) is useful in developing our knowledge of spatial and temporal variations during marine-based ice sheet ...
    • Reviewing the Cenozoic Net Erosion of the Barents Sea Shelf 

      Lasabuda, Amando Putra Ersaid; Laberg, Jan Sverre; Knutsen, Stig-Morten; Rydningen, Tom Arne (Conference object; Konferansebidrag, 2019-01)
    • Revised ΔR values for the Barents Sea and its archipelagos as a pre-requisite for accurate and robust marine-based 14C chronologies 

      Pienkowski, Anna; Husum, Katrine; Furze, Mark; Missana, Amandine F.J.; Irvali, Nil; Divine, Dmitry V.; Eilertsen, Vårin Trælvik (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-11)
      The calibration of marine 14C dates requires the incorporation of regionally specific marine reservoir offsets known as ΔR, essential for accurate and meaningful inter-archive comparisons. Revised, regional ΔR (‘ΔRR’) values for the Barents Sea are presented for molluscs and cetaceans for the two latest iterations of the marine calibration curve, based on previously published pre-bomb live-collected ...
    • 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 ...
    • Rock glaciers in central Patagonia 

      Selley, Heather; Harrison, Stephan; Glasser, Neil; Wündrich, Olaf; Colson, Daniel; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-22)
      Active rock glaciers are ice and debris-cored landforms common in cold arid mountains. They have not been widely described in the Patagonian Andes of southern South America and here we provide the first rock glacier inventory for the Jeinimeni region to the east of the contemporary North Patagonian Icefield. Detailed analysis of available satellite imagery and fieldwork demonstrates the presence of ...
    • The role of deformation-reaction interactions to localize strain in polymineralic rocks: Insights from experimentally deformed plagioclase-pyroxene assemblages 

      Mansard, Nicolas; Stunitz, Holger; Raimbourg, Hugues; Précigout, Jacques (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-09)
      In order to study the mutual effect of deformation and mineral reactions, we have conducted shear experiments on fine-grained plagioclase-pyroxene assemblages in a Griggs-type solid-medium deformation apparatus. Experiments were performed at a constant shear strain rate of 10<sup>−5</sup> s<sup>−1</sup>, a confining pressure of 1 GPa and temperatures of 800, 850 and 900 °C. While the peak stress of ...