Viser treff 102-121 av 711

    • Correlation between tectonic stress regimes and methane seepage on the western Svalbard margin 

      Plaza-Faverola, Andreia; Keiding, Marie (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-15)
      Methane seepage occurs across the western Svalbard margin at water depths ranging from < 300 m, landward from the shelf break, to > 1000 m in regions just a few kilometres from the mid-ocean ridges in the Fram Strait. The mechanisms controlling seepage remain elusive. The Vestnesa sedimentary ridge, located on oceanic crust at a depth of 1000–1700 m, hosts a perennial gas hydrate and associated free ...
    • Correspondence: 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)
      As the title of the correspondence by Fossen et al. 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.
    • Crustal processes sustain Arctic abiotic gas hydrate and fluid flow systems 

      Waghorn, Kate Alyse; Vadakkepuliyambatta, Sunil; Plaza-Faverola, Andreia; Johnson, Joel E; Bünz, Stefan; Waage, Malin (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-30)
      The Svyatogor Ridge and surroundings, located on the sediment-covered western flank of the Northern Knipovich Ridge, host extensive gas hydrate and related fluid flow systems. The fluid flow system here manifests in the upper sedimentary sequence as gas hydrates and free gas, indicated by bottom simulating reflections (BSRs) and amplitude anomalies. Using 2D seismic lines and bathymetric data, we ...
    • Cryptic frenulates are the dominant chemosymbiotrophic fauna at Arctic and high latitude Atlantic cold seeps 

      Sen, Arunima; Duperron, Sebastien; Hourdez, Stephane; Piquet, Berenice; Léger, Nelly; Gebruk, Andrey; Le Port, Anne-Sophie; Svenning, Mette Marianne; Andersen, Ann C. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-28)
      We provide the first detailed identification of Barents Sea cold seep frenulate hosts and their symbionts. Mitochondrial COI sequence analysis, in combination with detailed morphological investigations through both light and electron microscopy was used for identifying frenulate hosts, and comparing them to Oligobrachia haakonmosbiensis and Oligobrachia webbi, two morphologically similar species ...
    • Crystal rotations and alignment in spatially varying magma flows: 2-D examples of common subvolcanic flow geometries 

      Vachon, Remi Elie Celestin; Bazargan, Mohsen; Hieronymus, Christoph F.; Ronchin, Erika; Almqvist, Bjarne (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-31)
      Elongate inclusions immersed in a viscous fluid generally rotate at a rate that is different from the local angular velocity of the flow. Often, a net alignment of the inclusions develops, and the resulting shape preferred orientation of the particle ensemble can then be used as a strain marker that allows reconstruction of the fluid’s velocity field. Much of the previous work on the dynamics of ...
    • The current status of environmental forensic science in the member institutes of the European Network of Forensic Science Institutes (ENFSI) 

      Mäkelä, Tuukka; Huhtala, Sami; Lindqvist, Mimmi A.; Bucht, Rebecca (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-04)
      The paper presents the results of a questionnaire survey carried out by The Forensic laboratory of the National Bureau of Investigation (NBI-FL), aiming to get an overview of the current status of environmental forensic science (EFS) and environmental crimes investigation in the European Network of Forensic Science Institutes (ENFSI). A questionnaire was sent out to 71 ENFSI member institutes and ...
    • Cyclostratigraphic age constraining for Quaternary sediments in the Makarov Basin of the western Arctic Ocean using manganese variability 

      Park, Kwangkyu; Kim, Jung-Hyun; Asahi, Hirofumi; Polyak, Leonid; Khim, Boo-Keun; Schreck, Michael; Niessen, Frank; Kong, Gee Soo; Nam, Seung-Il (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-26)
      The Quaternary paleoenvironmental history of the Arctic Ocean remains uncertain, mainly due to the limited chronological constraints, especially beyond the 14C dating limits of accelerator mass spectrometry (AMS). The difficulty in establishing reliable chronostratigraphies is mainly attributed to low sedimentation rates and diagenetic sediment changes, resulting in very poor preservation of ...
    • Dark zone of the Greenland Ice Sheet controlled by distributed biologically-active impurities 

      Ryan, Jonathan C.; Hubbard, Alun Lloyd; Stibal, Marek; Irvine-Fynn, Tristam D.; Cook, Joseph; Smith, Lawrence C.; Cameron, Karen; Box, Jason E (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-14)
      Albedo—a primary control on surface melt—varies considerably across the Greenland Ice Sheet yet the specific surface types that comprise its dark zone remain unquantified. Here we use UAV imagery to attribute seven distinct surface types to observed albedo along a 25 km transect dissecting the western, ablating sector of the ice sheet. Our results demonstrate that distributed surface impurities—an ...
    • Dating submarine landslides using the transient response of gas hydrate stability 

      Portnov, Aleksei D; You, Kehua; Flemings, Peter B.; Cook, Ann E.; Heidari, Mahdi; Sawyer, Derek E.; Bünz, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-02)
      Submarine landslides are prevalent on the modern-day seafloor, yet an elusive problem is constraining the timing of past slope failure. We present a novel age-dating technique based on perturbations to underlying gas hydrate stability caused by slide-impacted seafloor changes. Using three-dimensional (3-D) seismic data, we mapped an irregular bottom simulating reflection (BSR) underneath a submarine ...
    • Decadal trend of plankton community change and habitat shoaling in the Arctic gateway recorded by planktonic foraminifera 

      Greco, Mattia; Werner, Kristin; Zamelczyk, Katarzyna; Rasmussen, Tine Lander; Kucera, Michal (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-16)
      The Fram Strait plays a crucial role in regulating the heat and sea-ice dynamics in the Arctic. In response to the ongoing global warming, the marine biota of this Arctic gateway is experiencing significant changes with increasing advection of Atlantic species. The footprint of this ‘Atlantification’ has been identified in isolated observations across the plankton community, but a systematic, ...
    • Deciphering late Devonian–early Carboniferous P–T–t path of mylonitized garnet-mica schists from Prins Karls Forland, Svalbard 

      Kośmińska, Karolina; Spear, Frank S.; Majka, Jarosław; Faehnrich, Karol; Manecki, Maciej; Piepjohn, Karsten; Dallmann, Winfried (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-03)
      Quartz‐in‐garnet inclusion barometry integrated with trace element thermometry and calculated phase relations is applied to mylonitized schists of the Pinkie unit cropping out on the island of Prins Karls Forland, western part of the Svalbard Archipelago. This approach combines conventional and novel techniques and allows deciphering of the pressure–temperature (<i>P–T</i>) evolution of mylonitic ...
    • Deconvoluting complex structural histories archived in brittle fault zones 

      Viola, Giulio; Scheiber, Thomas; Fredin, Ola; Zwingmann, Horst; Margreth, A (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-16)
      Brittle deformation can saturate the Earth’s crust with faults and fractures in an apparently chaotic fashion. The details of brittle deformational histories and implications on, for example, seismotectonics and landscape, can thus be difficult to untangle. Fortunately, brittle faults archive subtle details of the stress and physical/chemical conditions at the time of initial strain localization ...
    • Deep ocean 14C ventilation age reconstructions from the Arctic Mediterranean reassessed 

      Ezat, Mohamed; Rasmussen, Tine Lander; Skinner, Luke C.; Zamelczyk, Katarzyna (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-13)
      The present-day ocean ventilation in the Arctic Mediterranean (Nordic Seas and Arctic Ocean), via transformation of northward inflowing warm Atlantic surface water into cold deep water, affects regional climate, atmospheric circulation and carbon storage in the deep ocean. Here we study the glacial evolution of the Arctic Mediterranean circulation and its influence on glacial climate using ...
    • Deep ocean storage of heat and CO2 in the Fram Strait, Arctic Ocean during the last glacial period 

      Ezat, Mohamed; Rasmussen, Tine Lander; Hain, Mathis P.; Greaves, Mervyn; Rae, James W.B.; Zamelczyk, Katarzyna; Marchitto, Thomas M.; Szidat, Sönke; Skinner, Luke C. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-19)
      The Fram Strait is the only deep gateway between the Arctic Ocean and the Nordic Seas and thus is a key area to study past changes in ocean circulation and the marine carbon cycle. Here, we study deep ocean temperature, δ18O, carbonate chemistry (i.e., carbonate ion concentration [CO32−]), and nutrient content in the Fram Strait during the late glacial (35,000–19,000 years BP) and the Holocene based ...
    • Deep-time Arctic climate archives: high-resolution coring of Svalbard's sedimentary record – SVALCLIME, a workshop report 

      Senger, Kim; Kulhanek, Denise; Jones, Morgan T.; Smyrak-Sikora, Aleksandra; Planke, Sverre; Zuchuat, Valentin; foster, William J.; Grundvåg, Sten-Andreas; Lorenz, Henning; Ruhl, Micha; Sliwinska, Kasia K.; Vickers, Madeleine L.; Xu, Weimu (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-26)
      ​​​​​​​We held the MagellanPlus workshop SVALCLIME “Deep-time Arctic climate archives: high-resolution coring of Svalbard's sedimentary record”, from 18 to 21 October​​​​​​​ 2022 in Longyearbyen, to discuss scientific drilling of the unique high-resolution climate archives of Neoproterozoic to Paleogene age present in the sedimentary record of Svalbard. Svalbard is globally unique in that it facilitates ...
    • Deep-water sand transfer by hyperpycnal flows, the Eocene of Spitsbergen, Arctic Norway 

      Grundvåg, Sten-Andreas; Helland-Hansen, William; Johannessen, Erik P.; Eggenhuisen, Joris T.; Pohl, Florian; Spychala, Yvonne T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-11)
      Flood-generated hyperpycnal flows are dense, sediment-laden, turbulent flows that can form long-lived, bottom-hugging turbidity currents, which undoubtedly transport large volumes of fine-grained sediments into the ocean. However, their ability in transferring sand into deep-water basins is debated. This study presents sedimentological evidence of sandy hyperpycnal flow deposits (hyperpycnites) in ...
    • Deformation Behavior and Inferred Seismic Properties of Tonalitic Migmatites at the Time of Pre‐melting, Partial Melting, and Post‐Solidification 

      Shao, Yilun; Piazolo, Sandra; Liu, Yongjiang; Lee, Amicia; Jin, Wei; Li, Weimin; Liang, Chenyue; Wen, Quanbo (Journal article; Tidsskriftartikkel, 2021-01-21)
      As seismic data from the lower crust becomes more readily available, it is important to link seismic properties to the ongoing processes within lower crustal evolution. This includes high temperature, pre‐ and post‐migmatization solid state deformation as well as melt‐present deformation. We selected two tonalitic migmatites with variable former melt content (one metatexite and one diatexite) from ...
    • Deformation mechanisms accommodating progressive simple shear thrusting of quartzite and metacarbonate in the southwestern Espinhaço Range, Brazil 

      Taufner, Rhander; Lagoeiro, Leonardo E.; Cavalcante, Carolina; Barbosa, Paola; Silveira, Camila Santos (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-09)
      The accommodation of low-temperature ductile deformation in foreland fold-and-thrust belts is often described in terms of outcrop-based geometric analysis, but microtextural observations are also important, as they relate stress, strain, fluids and temperature and thus the rheology in the peripheral part of the orogen. Such microtextural observations are lacking from the foreland part of the Araçuaí ...
    • Deglacial dynamics of the Vestfjorden - Trænadjupet palaeo-ice stream, northern Norway 

      Laberg, Jan Sverre; Eilertsen, Raymond S; Salomonsen, Gaute R. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-05-18)
      Few well‐dated records of the deglacial dynamics of the large palaeo‐ice streams of the major Northern Hemisphere ice sheets are presently available, a prerequisite for an improved understanding of the ice‐sheet response to the climate warming of this period. Here we present a transect of gravity‐core samples through Trænadjupet and Vestfjorden, northern Norway, the location of the Trænadjupet – ...
    • Deglacial–Holocene Svalbard paleoceanography and evidence of Melt Water Pulse 1B 

      Tian, Skye Y.; Yasuhara, Moriaki; Hong, Y.; Huang, H.-H.; Iwatani, H.; Chiu, W.-T. R.; Mamo, Bryoni; Okahashi, Hisayo; Rasmussen, Tine Lander (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-09)
      Better understanding of deglacial meltwater pulses (MWPs) is imperative for future predictions of human-induced warming and abrupt sea-level change because of their potential for catastrophic damage. However, our knowledge of the second largest meltwater pulse MWP-1B that occurred shortly after the start of the Holocene interglacial remains very limited. Here, we studied fossil ostracods as ...