Now showing items 118-137 of 316

    • High-resolution 3D seismic exhibits new insights into the middle-late Pleistocene stratigraphic evolution and sedimentary processes of the Bear Island trough mouth fan 

      Waage, Malin; Bünz, Stefan; Bøe, Reidulv; Mienert, Jurgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-21)
      Arctic Ocean trough mouth fans (TMFs) represent a valuable archive of glacial-interglacial sedimentary processes that are especially important when reconstructing pre-Weichselian glaciations that may lack distinct imprints on the shelves. In 2011, we acquired the first high-resolution 3D seismic cube (~3 m vertical and 6 m horizontal resolution) on the continental slope of the SW Barents Sea by use ...
    • 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 ...
    • A High-Resolution Geomagnetic Relative Paleointensity Record From the Arctic Ocean Deep-Water Gateway Deposits During the Last 60 kyr 

      Caricchi, Chiara; Lucchi, Renata Giulia; Sagnotti, Leonardo; Macri, Patrizia; Di Roberto, Alessio; Del Carlo, Paola; Husum, Katrine; Laberg, Jan Sverre; Morigi, Caterina (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-16)
      We present a paleomagnetic and rock magnetic data set from two long sediment cores collected from Bellsund and Isfjorden contourite drifts located on the eastern side of the Fram Strait (western Spitsbergen margin). The data set gave the opportunity to define the behavior of the past geomagnetic field at high latitude and to constrain the palaeoclimatic events that occurred in a time framework ...
    • High-resolution landform assemblage along a buried glacio-erosive surface in the SW Barents Sea revealed by P-Cable 3D seismic data 

      Bellwald, Benjamin; Planke, Sverre; Lebedeva-Ivanova, Nina; Piasecka, Emilia Daria; Andreassen, Karin (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-01)
      The Quaternary sedimentary record in the Arctic captures a diverse and evolving range of landscapes reflecting cli-mate changes. Here we study the geological landform assemblage of the Upper Regional Unconformity (URU) in theSW Barents Sea. The aims are (i) to characterize buried geological landforms on a meter-scale resolution, (ii) to un-derstand their link with underlying structures, and (iii) ...
    • High-resolution underwater laser spectrometer sensing provides new insights into methane distribution at an Arctic seepage site 

      Jansson, Pär; Triest, Jack; Grilli, Roberto; Ferré, Benedicte; Silyakova, Anna; Mienert, Jurgen; Chappellaz, Jérôme (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-13)
      Methane (CH4) in marine sediments has the potential to contribute to changes in the ocean and climate system. Physical and biochemical processes that are difficult to quantify with current standard methods such as acoustic surveys and discrete sampling govern the distribution of dissolved CH4 in oceans and lakes. Detailed observations of aquatic CH4 concentrations are required for a better understanding ...
    • The history and future trends of ocean warming-induced gas hydrate dissociation in the SW Barents Sea 

      Vadakkepuliyambatta, Sunil; Chand, Shyam; Bünz, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-13)
      The Barents Sea is a major part of the Arctic where the Gulf Stream mixes with the cold Arctic waters. Late Cenozoic uplift and glacial erosion have resulted in hydrocarbon leakage from reservoirs, evolution of fluid flow systems, shallow gas accumulations, and hydrate formation throughout the Barents Sea. Here we integrate seismic data observations of gas hydrate accumulations along with gas hydrate ...
    • Holocene atmospheric circulation in the central North Pacific: A new terrestrial diatom and d18O dataset from the Aleutian Islands 

      Bailey, Hannah L.; Kaufman, Darrell S.; Sloane, Hilary J.; Hubbard, Alun Lloyd; Henderson, Andrew C.G.; Leng, Melanie J.; Meyer, Hanno; Welker, Jeffrey M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-02)
      The North Pacific is a zone of cyclogenesis that modulates synoptic-scale atmospheric circulation, yet there is a paucity of instrumental and paleoclimate data to fully constrain its long-term state and variability. We present the first Holocene oxygen isotope record (δ<sup>18</sup>O<sub>diatom</sub>) from the Aleutian Islands, using siliceous diatoms preserved in Heart Lake on Adak Island (51.85° ...
    • Holocene development of subarctic permafrost peatlands in Finnmark, northern Norway 

      Kjellman, Sofia E.; Axelsson, Pia E.; Etzelmüller, Bernd; Westermann, Sebastian; Sannel, A. Britta K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-01)
      Subarctic permafrost peatlands are important soil organic carbon pools, and improved knowledge about peat properties and peatland sensitivity to past climate change is essential when predicting future response to a warmer climate and associated feedback mechanisms. In this study, Holocene peatland development and permafrost dynamics of four subarctic peat plateaus in Finnmark, northern Norway have ...
    • Holocene relative sea-level changes and deglaciation chronology in Finnmark, northern Norway 

      Bennike, Ole; Romundset, Anders; Bondevik, Stein (Preprint; Manuskript, 2010-10)
      The outer coast of Finnmark in northern Norway is where the former Fennoscandian and Barents Sea ice sheets coalesced. This key area for isostatic modelling and deglaciation history of the ice sheets has abundant raised shorelines, but only a few existing radiocarbon dates relate to them. Here we present three Holocene sea-level curves based on radiocarbon ages from deposits in isolation basins ...
    • Holocene sub-centennial evolution of Atlantic water inflow and sea ice distribution in the western Barents Sea 

      Berben, Sarah; Husum, Katrine; Cabedo Sanz, Patricia; Belt, Simon T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-01-23)
      A marine sediment core (JM09-KA11-GC) from the Kveithola Trough at the western Barents Sea margin has been investigated in order to reconstruct sub-surface temperatures and sea ice distribution at a sub-centennial resolution throughout the Holocene. The relationship between past variability of Atlantic water inflow and sea ice distribution has been established by measurement of planktic foraminifera, ...
    • How robust are in situ observations for validating satellite-derived albedo over the dark zone of the Greenland Ice Sheet? 

      Ryan, J.C.; Hubbard, Alun Lloyd; Irvine-Fynn, T.; Doyle, S.H.; Cook, J.M.; Stibal, Marek; Box, J.E. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-17)
      Calibration and validation of satellite‐derived ice sheet albedo data require high‐quality, in situ measurements commonly acquired by up and down facing pyranometers mounted on automated weather stations (AWS). However, direct comparison between ground and satellite‐derived albedo can only be justified when the measured surface is homogeneous at the length‐scale of both satellite pixel and in situ ...
    • Hydrate occurrence in Europe: A review of available evidence 

      Minshull, Timothy A.; Marin-Moreno, Hector; Betlem, Peter; Bialas, Joerg; Bünz, Stefan; Burwicz, Ewa; Cameselle, Alejandra L.; Cifci, Gunay; Giustiniani, Michela; Hillman, Jess I.T.; Hölz, Sebastian; Hopper, John R.; Ion, Gabriel; Leon, Ricardo; Magalhaes, Vitor; Makovsky, Yizhaq; Mata, Maria-Pilar; Max, Michael D.; Nielsen, Tove; Okay, Seda; Ostrovsky, Ilia; O'Neil, Nick; Pinheiro, Luis M.; Plaza-Faverola, Andreia; Rey, Daniel; Roy, Srikumar; Schwalenberg, Katrin; Senger, Kim; Vadakkepuliyambatta, Sunil; Vasilev, Atanas; Vázquez, Juan-Tomás (Journal article; Tidsskriftartikkel, 2019-08-16)
      Large national programs in the United States and several Asian countries have defined and characterised their marine methane hydrate occurrences in some detail, but European hydrate occurrence has received less attention. The European Union-funded project “Marine gas hydrate – an indigenous resource of natural gas for Europe” (MIGRATE) aimed to determine the European potential inventory of exploitable ...
    • Ice-sheet-driven methane storage and release in the Arctic 

      Portnov, Aleksei D; Vadakkepuliyambatta, Sunil; Mienert, Jurgen; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-07)
      It is established that late-twentieth and twenty-first century ocean warming has forced dissociation of gas hydrates with concomitant seabed methane release. However, recent dating of methane expulsion sites suggests that gas release has been ongoing over many millennia. Here we synthesize observations of B1,900 fluid escape features—pockmarks and active gas flares—across a previously glaciated ...
    • Ice-stream dynamics of the SW Barents Sea revealed by high-resolution 3D seismic imaging of glacial deposits in the Hoop area 

      Bellwald, Benjamin; Planke, Sverre; Piasecka, Emilia Daria; Matar, M.A.; Andreassen, Karin (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-07)
      Recent developments in seismic acquisition systems and seismic data visualization have contributed to improve the imaging of seismic geomorphologies over a broad range of topics. This study focuses on a new high-resolution P-Cable 3D seismic cube located in the Hoop area in the SW Barents Sea. The scientific motivations of the study are (1) to document glacial landforms on a meter-scale, (2) to study ...
    • 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; Preprint; Manuskript, 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 ...
    • Identifying past petroleum exploration related drill cutting releases and influences on the marine environment and benthic foraminiferal communities, Goliat Field, SW Barents Sea, Norway 

      Sørensen, Steffen Aagaard; Junttila, Juho; Dijkstra, Noortje (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-01)
      The present multiproxy investigation of marine sediment cores aims at: 1) Identifying dispersion of petroleum exploration related drill cutting releases within the Goliat Field, Barents Sea in 2006/07 and 2) Assessing past and present influence of drill cuttings on the marine environment. The cores were recovered 5, 30, 60, 125 and 250 m from the drill site in the eastward downstream direction.<p> ...
    • Image based quantitative comparisons indicate heightened megabenthos diversity and abundance at a site of weak hydrocarbon seepage in the southwestern Barents Sea 

      Sen, Arunima; Chitkara, Chestaa; Hong, Wei-Li; Lepland, Aivo; Cochrane, Sabine; Di Primio, Rolando; Brunstad, Harald (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-08)
      <p><i>Background - </i>High primary productivity in the midst of high toxicity defines hydrocarbon seeps; this feature usually results in significantly higher biomass, but in lower diversity communities at seeps rather than in the surrounding non-seep benthos. Qualitative estimates indicate that this dichotomy does not necessarily hold true in high latitude regions with respect to megafauna. Instead, ...
    • Impact of Arctic shelf summer stratification on Holocene climate variability 

      Thibodeau, Benoit; Bauch, Henning A.; Knies, Jochen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-21)
      Understanding the dynamic of freshwater and sea-ice export from the Arctic is crucial to better comprehend the potential near-future climate change consequences. Here, we report nitrogen isotope data of a core from the Laptev Sea to shed light on the impact of the Holocene Siberian transgression on the summer stratification of the Laptev Sea. Our data suggest that the oceanographic setting was ...
    • 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 ...
    • 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 ...