Viser treff 821-840 av 1012

    • Origin and K-Ar age of the phreatomagmatic breccia at the Trepča Pb-Zn-Ag skarn deposit, Kosovo: Implications for ore-forming processes 

      Strmic Palinkas, Sabina; Palinkaš, Ladislav A.; Mandić, Magda; Roller-Lutz, Zvjezdana; Pécskay, Zoltan; Maliqi, Gani; Bermanec, Vladimir (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-02-29)
      The Trepča Pb-Zn-Ag skarn deposit in Kosovo is spatially and temporarily related to the phreatomagmatic breccia of Oligocene age (~23Ma). The deposit shows features typical for skarn deposits worldwide, including a stage of isochemical metamorphism, a prograde stage of an anhydrous, low oxygen and low sulfur fugacity character, and a retrograde stage characterized by an increase in the water ...
    • The last 2 Myr of accretionary wedge construction in the central Hikurangi margin (North Island, New Zealand): Insights from structural modeling 

      Ghisetti, Francesca C.; Barnes, Philip M.; Ellis, Susan; Plaza-Faverola, Andreia; Barker, Daniel H.N. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-07-17)
      Three depth-converted and geologically interpreted seismic profiles provide a clear image of the offshore outer accretionary wedge associated with oblique subduction of the Pacific Plate beneath the central Hikurangi margin. Plio-Quaternary turbidites deposited over the pelagic cover sequence of the Hikurangi Plateau have been accreted to the margin by imbrication along E-verging thrust faults that ...
    • Splay fault branching from the Hikurangi subduction shear zone: Implications for slow slip and fluid flow 

      Plaza-Faverola, Andreia; Henrys, Stuart; Pecher, Ingo; Wallace, L.; Klaeschen, Dirk (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-25)
      Prestack depth migration data across the Hikurangi margin, East Coast of the North Island, New Zealand, are used to derive subducting slab geometry, upper crustal structure, and seismic velocities resolved to ∼14 km depth. We investigate the potential relationship between the crustal architecture, fluid migration, and short-term geodetically determined slow slip events. The subduction interface is ...
    • Reconstruction of hydrographic changes in the southern Norwegian Sea during the past 135 kyr and the impact of different foraminiferal Mg/Ca cleaning protocols 

      Ezat, Mohamed; Rasmussen, Tine Lander; Groeneveld, Jeroen (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-08-20)
      The shallow subsurface hydrography in the southern Norwegian Sea during the past 135,000 years was investigated using parallel measurements of Mg/Ca and δ18O in shells of the planktic foraminiferal species Neogloboquadrina pachyderma. Two cleaning methods were applied prior to Mg/Ca analysis, “Mg cleaning” and “full cleaning” methods. Different results were obtained, which are most likely due to a ...
    • Simulating seismic chimney structures as potential vertical migration pathways for CO2 in the Snøhvit area, SW Barents Sea: model challenges and outcomes 

      Tasianas, Alexandros; Mahl, Lena; Darcis, Melanie; Bünz, Stefan; Class, Holger (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-16)
      Carbon capture and storage (CCS) activities at the Snøhvit field, Barents Sea, will involve carrying out an analysis to determine which parameters affect the migration process of CO2 from the gas reservoir, to what degree they do so and how sensitive these parameters are to any changes. This analysis will aim to evaluate the effects of applying a broad but realistic range of reservoir, fault and gas ...
    • The build-up, configuration, and dynamical sensitivity of the Eurasian ice-sheet complex to Late Weichselian climatic and oceanic forcing 

      Patton, Henry; Hubbard, Alun Lloyd; Andreassen, Karin; Winsborrow, Monica; Stroeven, Arjen P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-01)
      The Eurasian ice-sheet complex (EISC) was the third largest ice mass during the Last Glacial Maximum (LGM), after the Antarctic and North American ice sheets. Despite its global significance, a comprehensive account of its evolution from independent nucleation centres to its maximum extent is conspicuously lacking. Here, a first-order, thermomechanical model, robustly constrained by empirical evidence, ...
    • Evolution of a high-latitude sediment drift inside a glacially-carved trough based on high-resolution seismic stratigraphy (Kveithola, NW Barents Sea) 

      Rebesco, Michele; Özmaral, Asli; Urgeles, Roger; Accettella, Daniela; Lucchi, Renata G.; Rüther, Denise Christina; Winsborrow, Monica; Llopart, Jaume; Caburlotto, Andrea; Lantzsch, Hendrik; Hanebuth, Till J.J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-01)
      Kveithola is a glacially-carved, E-W trending trough located in the NW Barents Sea, an epicontinental shelf sea of the Arctic Ocean located off northern Norway and Russia. A set of confined sediment drifts (the “Kveithola Drift”) is located in the inner part of the trough. In general, drift deposits are commonly characterized by high lateral continuity, restricted occurrence of hiatuses and relatively ...
    • Distribution and characteristics of overdeepenings beneath the Greenland and Antarctic ice sheets: Implications for overdeepening origin and evolution 

      Patton, Henry; Swift, D.A.; Clark, C.D.; Livingstone, Stephen J.; Cook, S.J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-15)
      Glacier bed overdeepenings are ubiquitous in glacier systems and likely exert significant influence on ice dynamics, subglacial hydrology, and ice stability. Understanding of overdeepening formation and evolution has been hampered by an absence of quantitative empirical studies of their distribution and morphology, with process insights having been drawn largely from theoretical or numerical studies. ...
    • Linking the basement geology along the Africa-South America coasts in the South Atlantic 

      Konopasek, Jiri; Slama, Jiri; Košler, Jan (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-13)
      The match of geological units of the dissected Kaoko-Dom Feliciano-Gariep orogenic system exposed along the coasts of the South Atlantic is poorly understood. Two suites of intrusive rocks crop out in the Angra Fria Bay area, a part of the Coastal Terrane of the Kaoko Belt in Namibia. U–Pb zircon dating of three samples from the younger suite provided ages of 574 ± 6, 586 ± 3 and 584 ± 7 Ma, similar ...
    • Position, swimming direction and group size of fin whales (Balaenoptera physalus) in the presence of a fast-ferry in the Bay of Biscay 

      Aniceto, Ana Sofia Albuquerque Lima; Carroll, JoLynn; Tetley, Michael J; van Oosterhout, Cock (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-12)
      We analyze group size, swimming direction and the orientation of fin whales relative to a fast ferry in the Bay of Biscay. Fin whale groups (≥3 individuals) were on average closer to the vessel than single individuals and pairs (F1,114 = 4.94, p = 0.028) and were more often observed within a high-risk angle ahead of the ferry (binomial probability: p = 7.60 × 10−11). Also, small groups tend to swim ...
    • Gas hydrate stability zone of the Barents Sea and Kara Sea region 

      Klitzke, Peter; Luzi-Helbing, Manja; Schicks, Judith M.; Cacace, Mauro; Jacquey, Antoine B.; Scheck-Wenderoth, Magdalena; Faleide, Jan Inge (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-29)
      In this study we assess the present-day gas hydrate stability zone for the Barents Sea and Kara Sea region. Thereby, we make use of a data-based 3D lithosphere-scale pressure and thermal model. The resulting gas hydrate stability zone varies within >1km across the study area and strongly correlates with the local geological settings and the corresponding geothermal gradient. Gas hydrates containing ...
    • Extraordinary runoff from the Greenland ice sheet in 2012 amplified by hypsometry and depleted firn retention 

      Mikkelsen, A.B.; Hubbard, Alun Lloyd; MacFerrin, Mike; Box, Jason Eric; Doyle, Sam H.; Fitzpatrick, Andrew; Hasholt, Bent; Bailey, Hannah L.; Lindbäck, Katrin; Pettersson, Rickard (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-30)
      It has been argued that the infiltration and retention of meltwater within firn across the percolation zone of the Greenland ice sheet has the potential to buffer up to  ∼  3.6 mm of global sea-level rise (Harper et al., 2012). Despite evidence confirming active refreezing processes above the equilibrium line, their impact on runoff and proglacial discharge has yet to be assessed. Here, we compare ...
    • Past methane emissions in the earliest Pleistocene on Yermak Plateau, NW Svalbard. 

      Heimdal, Karianne (Master thesis; Mastergradsoppgave, 2016-05-15)
      Hole 912A (Ocean Drilling Program (ODP) Leg 151) drilled on the Yermak Plateau (eastern Arctic Ocean) is used to investigate past methane emissions in the earliest Pleistocene. Preliminary work showed depleted δ¹³C values at 93-96 meters below sea floor (mbsf), and an increase in methane concentration between 11, 5 and 23 mbsf. A secondary sampling focused on intervals between 10 and 23 mbsf (core ...
    • Ice sheet dynamics in the Brunt Basin, Weddell Sea, Antarctica, since the last glacial period 

      Sørli, Simon Helle (Master thesis; Mastergradsoppgave, 2016-11-15)
      High-resolution swath bathymetry, TOPAS sub-bottom profiles and four gravity cores from the Brunt Basin, southeastern Weddell Sea in Antarctica, were analysed with the purpose of reconstructing the ice sheet dynamics since the last glacial. Data collection was carried out by the British Antarctic Survey (BAS) and data analyses were carried out in a collaboration between the Department of Geosciences ...
    • Bretilbaketrekningshistorie og landformer foran Steindalsbreen, Lyngen, Troms 

      Nilsen, Carina (Master thesis; Mastergradsoppgave, 2016-06-15)
      Steindalen er lokalisert sør på Lyngenhalvøya, i Troms fylke. Steindalsbreen er en av de lettest tilgjengelige breer i området. Dette gjør breen til et yndet turmål, men det gjør det også lettere å studere en bre på nært hold. Undersøkelse av Steindalsbreen har foregått ved hjelp av feltturer til området, ved å studere foto og flybilder over området og ved å sammenstille data samlet over mange år, ...
    • Structure and flow properties of syn-rift border faults: The interplay between fault damage and fault-related chemical alteration (Dombjerg Fault, Wollaston Forland, NE Greenland) 

      Kristensen, Thomas B.; Rotevatn, Atle; Peacock, David C.P.; Henstra, Gijs A.; Midtkandal, Ivar; Grundvåg, Sten-Andreas (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-29)
      Structurally controlled, syn-rift, clastic depocentres are of economic interest as hydrocarbon reservoirs; understanding the structure of their bounding faults is of great relevance, e.g. in the assessment of fault-controlled hydrocarbon retention potential. Here we investigate the structure of the Dombjerg Fault Zone (Wollaston Forland, NE Greenland), a syn-rift border fault that juxtaposes syn-rift ...
    • Petrographic investigation of methane-derived authigenic carbonate crusts from Barents Sea and Norwegian Sea 

      Røde, Silje (Master thesis; Mastergradsoppgave, 2016-06-15)
      Methane-derived authigenic carbonate crusts from four seepage sites at the Loppa High in the southwestern Barents Sea, and one seepage site at Hola, off Vesterålen in the Norwegian Sea, have been investigated, with the main focus of understanding if and how the tests of benthic and planktonic foraminifera occurring in the crusts could serve as nucleation centers for the precipitated carbonates.
    • Paleoceanographic development in Leirdjupet, during the last deglaciation 

      Tønnessen, Lasse Aase (Master thesis; Mastergradsoppgave, 2016-08-23)
      The focus of this master thesis is to investigate the paleoenvironmental and paleoceanography during the last deglaciation in Leirdjupet, a small submarine trough in the southwestern Barents Sea. The lower half of the piston corer HH15-1303PC has been investigated for the distribution pattern of benthic foraminifera faunas, ice rafted debris (IRD), lithology and oxygen and carbon isotopes covering; ...
    • Reconstructions of paleoceanography and ice retreat based on benthic foraminifera, stable isotopes and sedimentological investigations from the northwestern Barents Sea south of Nordaustlandet, Svalbard 

      Eilertsen, Vårin Trælvik (Master thesis; Mastergradsoppgave, 2016-07-12)
      One gracity core NP05–11–49GC was retrieved from a 320 m water depth in the central part of Erik Eriksen Strait, south of Nordaustlandet, northwestern Barents Sea. The core was investigated for benthic foraminiferal distribution patterns, stable isotopes and sedimentological parameters in order to reconstruct the Late Weichselian deglaciation and Holocene paleoenvironment and paleoceanography of the ...
    • Metamorphic conditions in the Coastal-Punta del Este Terrane of the Kaoko-Dom Feliciano Belt in Namibia and Uruguay 

      Skagseth, Ida Grindal (Master thesis; Mastergradsoppgave, 2016-06-24)
      The metasediementary rocks of the Coastal Terrane in the Kaoko Belt (Namibia) and the meta-igneous rocks of the Punta del Este-Terrane in the Dom Feliciano Belt (Uruguay) both share one high-grade metamorphic event at approximately the same time of c. 650-630 Ma. Metamorphic conditions of this high-grade event were estimated in four samples from the Punta del Este Terrane and two samples from ...