Viser treff 501-520 av 729

    • 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 ...
    • Methane at Svalbard and over the European Arctic Ocean 

      Platt, Stephen Matthew; Eckhardt, Sabine; Ferré, Benedicte; Fisher, Rebecca E.; Hermansen, Ove; Jansson, Pär; Lowry, David; Nisbet, Euan G.; Pisso, Ignacio; Schmidbauer, Norbert; Silyakova, Anna; Stohl, Andreas; Svendby, Tove Marit; Vadakkepuliyambatta, Sunil; Mienert, Jurgen; Myhre, Cathrine Lund (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-05)
      Methane (CH<sub>4</sub>) is a powerful greenhouse gas. Its atmospheric mixing ratios have been increasing since 2005. Therefore, quantification of CH<sub>4</sub> sources is essential for effective climate change mitigation. Here we report observations of the CH<sub>4</sub> mixing ratios measured at the Zeppelin Observatory (Svalbard) in the Arctic and aboard the research vessel (RV) Helmer Hanssen ...
    • Comment on“The Keisarhjelmen detachment records Silurian–Devonian extensional collapse in Northern Svalbard” 

      Dallmann, Winfried; Piepjohn, Karsten (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-30)
      <p><i>Introduction</i>: The discussed area has been investigated since the 1960s. Scientists of the Norwegian Polar Institute, the Cambridge scholar environment, the University of Münster and others have mapped, described, interpreted and contributed to the discussion through decades. Very little of this is reflected in the paper by Braathen, Osmundsen, Maher, and Ganerød, (2018). A discussion of ...
    • OBS Data Analysis to Quantify Gas Hydrate and Free Gas in the South Shetland Margin (Antarctica) 

      Song, Sha; Tinivella, Umberta; Giustiniani, Michela; Singhroha, Sunny; Bünz, Stefan; Cassiani, Giorgio (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-25)
      The presence of a gas hydrate reservoir and free gas layer along the South Shetland margin (offshore Antarctic Peninsula) has been well documented in recent years. In order to better characterize gas hydrate reservoirs, with a particular focus on the quantification of gas hydrate and free gas and the petrophysical properties of the subsurface, we performed travel time inversion of ocean-bottom ...
    • Ice‐rafting patterns on the western Svalbard slope 74–0 ka: interplay between ice‐sheet activity, climate and ocean circulation 

      Jessen, Simon Pind; Rasmussen, Tine Lander (Journal article; Tidsskriftartikkel, 2018-11-14)
      The distribution of ice‐rafted detritus (IRD) is studied in three cores from the western Svalbard slope (1130–1880 m water depth, 76–78°N) covering the period 74–0 ka. The aim was to provide new insight into the dynamics of the Svalbard–Barents Sea Ice Sheet during Marine Isotope Stages (MIS) 4–1 to get a better understanding of ice‐sheet interactions with changes in ocean circulation and climate ...
    • Late Cenozoic erosion estimates for the northern Barents Sea: Quantifying glacial sediment input to the Arctic Ocean 

      Lasabuda, Amando Putra Ersaid; Geissler, Wolfram H.; Laberg, Jan Sverre; Knutsen, Stig-Morten; Rydningen, Tom Arne; Berglar, Kai (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-14)
      A compilation of seismic data has been used to characterize the Neogene – Quaternary sedimentary succession of the northwestern Barents Sea continental margin to better understand the paleoenvironmental evolution and the sedimentary processes involved. The Neogene strata are dominated by contourites related to the ocean circulation established from the opening of the Fram Strait connecting the ...
    • Particle sources and downward fluxes in the eastern Fram strait under the influence of the west Spitsbergen current 

      Sanchez-Vidal, Anna; Veres, Oriol; Langone, Leonardo; Ferré, Benedicte; Calafat, Antoni; Canals, Miquel; Durrieu de Madron, Xavier; Heussner, Serge; Mienert, Jurgen; Grimalt, Joan O.; Pusceddu, Antonio; Danovaro, Roberto (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-06-10)
      <p>The carbon cycle of the Arctic Ocean is tightly regulated by land–atmosphere–cryosphere–ocean interactions. Characterizing these environmental exchanges and feedbacks is critical to facilitate projections of the carbon cycle under changing climate conditions. The environmental drivers of sinking particles including organic carbon (OC) to the deep-sea floor are investigated with four moorings ...
    • The Lower Cretaceous succession of the northwestern Barents Shelf: Onshore and offshore correlations 

      Grundvåg, Sten-Andreas; Marin Restrepo, Dora Luz; Kairanov, Bereke; Sliwinska, Kasia; Nøhr-Hansen, Henrik; Jelbye, Mads; Escalona Varela, Alejandro; Olaussen, Snorre (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-24)
      The Lower Cretaceous succession in the Barents Sea is listed as a potential play model by the Norwegian Petroleum Directorate. Reservoirs may occur in deep to shallow marine clastic wedges located in proximity to palaeo-highs and along basin margins. In addition, shelf-prism-scale clinoforms with high amplitude anomalies in their top- and bottomsets have been reported from reflection seismic but ...
    • The emergence of modern sea ice cover in the Arctic Ocean 

      Knies, Jochen; Cabedo-Sanz, Patricia; Belt, Simon T.; Baranwal, Soma; Fietz, Susanne; Rosell-Melé, Antoni (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-11-28)
      Arctic sea ice coverage is shrinking in response to global climate change and summer ice-free conditions in the Arctic Ocean are predicted by the end of the century. The validity of this prediction could potentially be tested through the reconstruction of the climate of the Pliocene epoch (5.33–2.58 million years ago), an analogue of a future warmer Earth. Here we show that, in the Eurasian sector ...
    • Redox-dependent niche differentiation provides evidence for multiple bacterial sources of glycerol tetraether lipids in lakes 

      Weber, Yuki; Sinninghe Damsté, Jaap S.; Zopfi, Jakob; De Jonge, Cindy; Gilli, Adrian; Schubert, Carsten J.; Lepori, Fabio; Lehmann, Moritz F.; Niemann, Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-23)
      Terrestrial paleoclimate archives such as lake sediments are essential for our understanding of the continental climate system and for the modeling of future climate scenarios. However, quantitative proxies for the determination of paleotemperatures are sparse. The relative abundances of certain bacterial lipids, i.e., branched glycerol dialkyl glycerol tetraethers (brGDGTs), respond to changes in ...
    • 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 ...
    • Subglacial water storage and drainage beneath the Fennoscandian and Barents Sea ice sheets 

      Shackleton, Calvin; Patton, Henry; Hubbard, Alun Lloyd; Winsborrow, Monica; Kingslake, Jonathan; Esteves, Mariana da Silveira Ramos; Andreassen, Karin; Greenwood, Sarah L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-17)
      Subglacial hydrology modulates how ice sheets flow, respond to climate, and deliver meltwater, sediment and nutrients to proglacial and marine environments. Here, we investigate the development of subglacial lakes and drainage networks beneath the Fennoscandian and Barents Sea ice sheets over the Late Weichselian. Utilizing an established coupled climate/ice flow model, we calculate high-resolution, ...
    • Neoproterozoic and post-Caledonian exhumation and shallow faulting in NW Finnmark from K–Ar dating and p/T analysis of fault rocks 

      Koehl, Jean-Baptiste P.; Bergh, Steffen G; Wemmer, Klaus (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-20)
      Well-preserved fault gouge along brittle faults in Paleoproterozoic, volcano-sedimentary rocks of the Raipas Supergroup exposed in the Alta–Kvænangen tectonic window in northern Norway yielded latest Mesoproterozoic (approximately 1050 15 Ma) to mid-Neoproterozoic (approximately 825–810 18 Ma) K–Ar ages. Pressure–temperature estimates from microtextural and mineralogy analyses of fault ...
    • The impact of submarine copper mine tailing disposal from the 1970s on Repparfjorden, northern Norway 

      Sternal, Beata; Junttila, Juho; Skirbekk, Kari; Forwick, Matthias; Carroll, JoLynn; Pedersen, Kristine Bondo (Journal article; Tidsskriftartikkel, 2017-05-10)
      We investigate the state of sedimentological environment and contaminant status of Repparfjorden (N Norway) impacted by submarine disposal of mine tailings during the 1970s using sedimentological and geochemical properties of seventeen sediment cores. The impact of tailings disposal is mainly restricted to the inner fjord where the discharge occurred. Sediment cores retrieved from the inner fjord ...
    • SUB-OCEAN: subsea dissolved methane measurements using an embedded laser spectrometer technology 

      Grilli, Roberto; Triest, Jack; Chappellaz, Jérôme; Calzas, Michel; Desbois, Thibault; Jansson, Pær; Guillerm, Christophe; Ferré, Benedicte; Lechevallier, Loïc; Ledoux, Victor; Romanini, Daniele (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-16)
      We present a novel instrument, the Sub-Ocean probe, allowing in situ and continuous measurements of dissolved methane in seawater. It relies on an optical feedback cavity enhanced absorption technique designed for trace gas measurements and coupled to a patent-pending sample extraction method. The considerable advantage of the instrument compared with existing ones lies in its fast response time of ...
    • Surface Meltwater Impounded by Seasonal Englacial Storage in West Greenland 

      Kendrick, A.K.; Schroeder, D.M.; Chu, W.; Young, T.J.; Christoffersen, P.; Todd, J.; Doyle, S.H.; Box, J.E.; Hubbard, A.; Hubbard, B.; Brennan, P.V.; Nicholls, K. W.; Lok, L.B. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-24)
      The delivery of surface meltwater through englacial drainage systems to the bed of the Greenland Ice Sheet modulates ice flow through basal lubrication. Recent studies in Southeast Greenland have identified a perennial firn aquifer; however, there are few observations quantifying the input or residence time of water within the englacial system and it remains unknown whether water can be stored within ...
    • Impact of natural (waves and currents) and anthropogenic (trawl) resuspension on the export of particulate matter to the open ocean: Application to the Gulf of Lion (NW Mediterranean) 

      Ferré, Bénédicte; Durrieu de Madron, X.; Estournel, C.; Ulses, G.; Le Corre, G. (Journal article; Tidsskriftartikkel; Peer reviewed, 2008-02-17)
      <p>Modern sediment deposits on continental margins form a vast reservoir of particulate matter that is regularly affected by resuspension processes. Resuspension by bottom trawling on shelves with strong fishing activity can modify the scale of natural disturbance by waves and currents. Recent field data show that the impact of bottom trawls on fine sediment resuspension per unit surface is comparable ...
    • Temperature observations from northernmost Greenland, 2006-2010 

      Schomacker, Anders; Larsen, Nicolaj K.; Bjørk, Anders A.; Kjær, Kurt H. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-31)
      Air-, surface-, and subsurface temperatures were recorded by automatic weather stations in Bliss Bugt and Moore Gletscher, Johannes V. Jensen Land, North coast of Greenland from 2006-2010. The mean annual surface temperature is -12.1 ℃ in Bliss Bugt and -13.8 ℃ at Moore Gletscher. In 20 cm depth below the surface at Moore Gletscher, the mean annual temperature is -13.2 ℃ (2007-2008). High-amplitude ...
    • Contour current driven continental slope-situated sandwaves with effects from secondary current processes on the Barents Sea margin offshore Norway 

      King, Edward L.; Bøe, Reidulv; Bellec, Valérie K.; Rise, Leif Christian; Skardhamar, Jofrid; Ferré, Bénédicte; Dolan, Margaret F.J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-04-15)
      Seabed data acquired from the southern Barents Sea continental margin offshore Norway reveal detailed morphology of large sandwave fields. Multibeam echosounder bathymetry and backscatter, shallow seismic, sediment samples and seabed video data collected by the MAREANO program have been used to describe and interpret the morphology, distribution and transport of the sandwaves. The bedforms lie on a ...
    • Methane seepage at Vestnesa Ridge (NW Svalbard) since the Last Glacial Maximum 

      Schneider, Andrea; Panieri, Giuliana; Lepland, Aivo; Consolaro, Chiara; Crémière, Antoine; Forwick, Matthias; Johnson, J.E.; Plaza-Faverola, Andreia; Sauer, Simone; Knies, Jochen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-21)
      <p>Multiple proxies in the geological record offshore NW Svalbard track shallow subseafloor diagenesis and seafloor methane seepage during the Last Glacial Maximum (LGM) extent and the disintegration of the Svalbard Barents Sea Ice Sheet (SBIS). Vestnesa Ridge, located at 79°N and in 1200 m water depth, is one of the northernmost known active methane seep sites and is characterised by a subseafloor ...