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norskBrowsing Fakultet for naturvitenskap og teknologi by Title
Now showing items 1660-1679 of 4765
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Geochemical characterisation of northern Norwegian fjord surface sediments: A baseline for further paleo-environmental investigations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-26)Norwegian fjord sediments are promising archives for very high resolution records of past environmental changes. Recent investigations of the modern depositional environment within fjords revealed that the accurate quantification of the inputs, sources, and sedimentary preservation of organic and inorganic material is crucial to decipher long term past climate signals in the sedimentary record ... -
Geochemical characteristics of sediment- and mafic rock-hosted Cu deposits in the Kåfjord area, Alta-Kvænangen Tectonic Window, Northern Norway
(Mastergradsoppgave; Master thesis, 2021-06-15)The Precambrian Alta-Kvænangen Tectonic Window (AKTW) located in the northern part of Norway, hosts different types of copper mineralization. Some of Cu occurrences have been previously mined, but their geochemical and stable isotope characteristics have not been a subject of detailed investigations, and therefore the relevant ore-forming processes are still poorly understood. This study, brings new ... -
Geochemical evidence for seabed fluid flow linked to the subsea permafrost outer border in the South Kara Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-16)Driven by rising bottom water temperatures, the thawing of subsea permafrost leads to an increase in fluid flow intensity in shallow marine sediments and results in the emission of methane into the water column. Limiting the release of permafrost-related gas hydrates and permafrost- sequestered methane into the global carbon cycle are of primary importance to the prevention of future Arctic Ocean ... -
Geochemical investigations of northern Norwegian fjord sediments - Sources and spatial variability of marine and terrigenous components
(Master thesis; Mastergradsoppgave, 2016-05-11)Fjords represent unique coastal marine environments with high sedimentation rates. They can be used for intensive investigations focusing on geochemical, mineralogical, biological, and sedimentological processes. In this study I investigate 42 surface sediment samples from the outer and inner parts of the Vestfjord, Ofotfjord, Tysfjord and tributary fjord arms in northern Norway. Samples were analysed ... -
The geochemical signature of Cu mineralisation preserved in stream sediments from the Alta-Kvænangen Tectonic Window, Northern Norway
(Master thesis; Mastergradsoppgave, 2021-06-13)The Paleoproterozoic Greenstone Belts of Fennoscandia are metamorphosed and deformed volcanic and sedimentary basins with a high metallic ore potential. One of those, the Alta-Kvænangen Tectonic Window (AKTW), is exposed as a window below the Caledonides of Northern Norway. The Kåfjord area located within the AKTW hosts numerous known Cu occurrences. The Cu mineralisation in Kåfjord occurs mostly ... -
Geochemistry of rutile-bearing veins at Engebøfjellet, Naustdal, Norway.
(Master thesis; Mastergradsoppgave, 2018-11-15)The Engebøfjellet eclogite, located in Naustdal, Norway, contain quartz veins with large rutile (TiO2) phenocrystals. Trace element composition of rutile deposited in veins and in the eclogite matrix was analysed with the use of LA-ICP-MS. The Nb content decrease with increasing V in the rutile, and contents of these elements vary depending on depositional environment. One quartz vein associated ... -
Geochemistry of sediment-hosted copper deposits and their environmental impact: A case study from the Nussir and Ulveryggen deposits, Repparfjord Tectonic Window, Northern Norway
(Doctoral thesis; Doktorgradsavhandling, 2019-11-07)Modern growing economy and technology require metals. Therefore mining is an unavoidable process. Mining in its turn results in the production of large amounts of mine waste. This research is focused on one type of mine waste, mine tailings, formed after the processing of Cu-sulphides deposits. Acid mine drainage (AMD) is a consequence of the oxidation of sulphide-rich rocks and has a drastic impact ... -
Geochemistry of the stratiform iron Dunderlandsdalen deposits, Nordland
(Master thesis; Mastergradsoppgave, 2019-05-15)The Dunderlandsdalen iron district, Northern Norway, hosts a world-class stratiform Fe-mineralization (total tonnage of ~500 Mt at 33% Fe). The iron ore units belong to the Dunderland Formation in the Ramnålia Nappe, which further belongs to the Rødingsfjellet Nappe of the Caledonian Uppermost Allochthon. Hematite and magnetite represent the principal ore minerals and are hosted by amphibolite grade ... -
Geochronology and chemostratigraphy of the 2.47–1.96 Ga rift-related volcano-sedimentary succession in the Karasjok Greenstone Belt, northern Norway, and its regional correlation within the Fennoscandian Shield
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-09)New geochronological data for the amphibolite-facies volcano-sedimentary Karasjok Greenstone Belt in northwestern Fennoscandia bracket its age between 2.47 and 1.96 Ga. The volcano-sedimentary units were deposited on the 3005 24 to 2776 69 Ma crystalline basement rocks of the Jergul Gneiss Complex. The lowermost Vuomegielas Formation contains rhyodacites dated at 2469 12 Ma that were deposited in ... -
Geodesic Webs and PDE Systems of Euler Equations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2008-10-30)We find necessary and sufficient conditions for the foliation defined by level sets of a function f(x1, ..., xn) to be totally geodesic in a torsion-free connection and apply them to find the conditions for d-webs of hypersurfaces to be geodesic, and in the case of flat connections, for d-webs (d ≥ n + 1) of hypersurfaces to be hyperplanar webs. These conditions are systems of generalized Euler ... -
Geodesic Webs of Hypersurfaces
(Working paper; Arbeidsnotat, 2008-12-11)In the present paper we study geometric structures associated with webs of hypersurfaces. We prove that with any geodesic (n + 2)-web on an n-dimensional manifold there is naturally associated a unique projective structure and, provide that one of web foliations is pointed, there is also associated a unique affine structure. The projective structure can be chosen by the claim that the leaves of all ... -
Geodesic Webs on a Two-Dimensional Manifold and Euler Equations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2008-10-30)We prove that any planar 4-web defines a unique projective structure in the plane in such a way that the leaves of the web foliations are geodesics of this projective structure. We also find conditions for the projective structure mentioned above to contain an affine symmetric connection, and conditions for a planar 4-web to be equivalent to a geodesic 4-web on an affine symmetric surface. Similar ... -
Geoelectrical structures beneath Spitsbergen-Svalbard derived from magnetotelluric imaging
(Doctoral thesis; Doktorgradsavhandling, 2016-05-27)In this thesis a series of geophysical surveys are carried out on the geologically important and remote Svalbard using magnetotelluric imaging, to constrain better the geology particularly defining geothermal resources. Magnetotellurics (MT) relays on natural source time-varying electric and magnetic field data measured at the earth’s surface in order to derive the subsurface resistivity structure. ... -
Geofaglig kunnskap og holdninger til norsk petroleumsnæring. En casestudie av Alta/Gohta
(Master thesis; Mastergradsoppgave, 2018-05-15)Denne oppgaven har som hovedfokus å belyse holdninger og geofaglig kunnskap knyttet til norsk petroleumsnæring. Oppgaven tar utgangspunkt i olje- og gassfunnene Alta/Gohta i Barentshavet. Et geofaglig litteraturstudie har blitt gjennomført for å oppnå en forståelse av funnenes geologi og særegenheter. Intervjuer med norsk petroleumsnærings hovedaktører; olje- og energidepartementet, oljedirektoratet, ... -
Geographical study of the stroke incidence and mortality rates using Bayesian analysis
(Master thesis; Mastergradsoppgave, 2023-09-21)There is large geographical variation in the stroke incidence rate worldwide. In addition, stroke is one of the diseases with highest mortality rate. In this thesis, our main focus is to examine if there are any geographical variation in stroke incidence and mortality rates in Norway. We approach this study using models within the Bayesian framework. Before performing analysis, we first introduce ... -
Geologi og klimaendringer
(Conference object; Konferansebidrag, 2010-09-02) -
Geological controlling parameters on seismic imaging of igneous intrusions on Svalbard
(Master thesis; Mastergradsoppgave, 2017-05-15)Imaging and mapping igneous intrusions such a sills and dykes has been one of the challenges in recent years. However, igneous intrusions in seismic data have properties that make them good targets for visualization, such as high amplitude and sophisticated shapes. 3D visualization methods are especially well suited for sill reflections. One of the main limitations of tying offshore seismic data to ... -
Geological controls of giant crater development on the Arctic seafloor
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-21)Active methane seepage occurs congruent with a high density of up to 1 km-wide and 35 m deep seafloor craters (>100 craters within 700 km<sup>2</sup> area) within lithified sedimentary rocks in the northern Barents Sea. The crater origin has been hypothesized to be related to rapid gas hydrate dissociation and methane release around 15–12 ka BP, but the geological setting that enabled and possibly ... -
Geological controls on fluid flow and gas hydrate pingo development on the Barents Sea margin
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-16)In 2014, the discovery of seafloor mounds leaking methane gas into the water column in the northwestern Barents Sea became the first to document the existence of non‐permafrost related gas hydrate pingos (GHP) on the Eurasian Arctic shelf. The discovered site is given attention because the gas hydrates occur close to the upper limit of the gas hydrate stability, thus may be vulnerable to climatic ... -
Geological fluid flow systems at Nyegga of the Mid-Norwegian margin
(Master thesis; Mastergradsoppgave, 2008-11-15)The Nyegga area is located at the north-eastern escarpment of the large Storegga Slide on the south of the Vøring plateau. The region has long been a natural laboratory for shallow fluid flow investigations, mainly due to the large number of fluid flow expressions found on the bathymetric and seismic data, and the possibility to investigate the relationship between fluid flow, gas hydrate formation ...
