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norskInstitutt for geovitenskap: Recent submissions
Now showing items 761-780 of 1012
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The inheritance of a Mesozoic landscape in western Scandinavia
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-28)In-situ weathered bedrock, saprolite, is locally found in Scandinavia, where it is commonly thought to represent pre-Pleistocene weathering possibly associated with landscape formation. The age of weathering, however, remains loosely constrained, which has an impact on existing geological and landscape evolution models and morphotectonic correlations. Here we provide new geochronological evidence ... -
Assessing impacts of simulated oil spills on the Northeast Arctic cod fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-04)We simulate oil spills of 1500 and 4500 m3/day lasting 14, 45, and 90 days in the spawning grounds of the commercial fish species, Northeast Arctic cod. Modeling the life history of individual fish eggs and larvae, we predict deviations from the historical pattern of recruitment to the adult population due to toxic oil exposures. Reductions in survival for pelagic stages of cod were 0–10%, up to a ... -
Acoustic generation of underwater cavities - Comparing modeled and measured acoustic signals generated by seismic air gun arrays
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-14)Underwater vapor cavities can be generated by acoustic stimulation. When the acoustic signals from several air guns are reflected from the sea surface, the pressure drop at some locations is sufficient for cavity growth and subsequent collapse. In this paper the generation of multiple water vapor cavities and their collapses are numerically modeled and the results are validated by comparing with ... -
Seepage from an arctic shallow marine gas hydrate reservoir is insensitive to momentary ocean warming
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-07)Arctic gas hydrate reservoirs located in shallow water and proximal to the sediment-water interface are thought to be sensitive to bottom water warming that may trigger gas hydrate dissociation and the release of methane. Here, we evaluate bottom water temperature as a potential driver for hydrate dissociation and methane release from a recently discovered, gas-hydrate-bearing system south of ... -
Episodic release of CO2 from the high-latitude North Atlantic Ocean during the last 135 kyrs
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-22)Antarctic ice cores document glacial-interglacial and millennial-scale variability in atmospheric pCO2 over the past 800 kyr. The ocean, as the largest active carbon reservoir on this timescale, is thought to have played a dominant role in these pCO2 fluctuations, but it remains unclear how and where in the ocean CO2 was stored during glaciations and released during (de)glacial millennial-scale ... -
Comparison and classification of an Arctic Transitional snow climate in Tromsø, Norway
(Master thesis; Mastergradsoppgave, 2017-10-11)Winter tourism in Tromsø has increased significantly over the last years, consequently also the skiing tourism. It is advertised that Tromsø has a mild coastal climate compared to other destinations at similar latitudes. Existing snow climate classes separate covers into a maritime, continental and a transitional class where persistent weak layers are rare in the maritime class. Rain and average air ... -
Volume measurements and change of Longyearbreen and Tellbreen, Svalbard
(Master thesis; Mastergradsoppgave, 2017-08-12)Climate change is a comprehensive field of research. The cryosphere is only a small portion of the entire spectrum but is still a very important constituent to try and understand. Thermal expansion of the oceans is the second largest cause for sea level rise around the world after the global melting of glaciers and ice sheets combined. Even the smallest valley glaciers, with small individual volumes, ... -
Strukturgeologisk og geomorfologisk studium av fjellskred ved Skredan, Tromsø kommune
(Master thesis; Mastergradsoppgave, 2017-09-06)Hovedfokuset med denne oppgaven har vært å få en forståelse for betydningen av sprø og duktile strukturer i berggrunnen i forbindelse med skredet ved Skredan. Studiet innebærer kartlegging av strukturer i berggrunnen, innsamling av strukturdata og kartlegging av morfologiske elementer og relatere de ulike morfologiske elementene til strukturer i berggrunnen. Berggrunnen ved Skredan består av godt ... -
Petroleum systems of the Barents shelf. A regional well-based study of the mesozoic
(Master thesis; Mastergradsoppgave, 2017-06-30)The entire Barents Sea area has experienced a complex geological evolution. From orogenic processes connected to Caledonian mountain building in Palaeozoic to basin formation related to the opening of the Atlantic Ocean in Paleogene. Uplift and erosion processes (Exhumation) that fined place in Ceinozoic contribute to erosion and redepositing of thick sedimentary sequences over Barents Sea ... -
Some giant submarine landslides do not produce large tsunamis
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-07)Landslides are the second-most important cause of tsunamis after earthquakes, and their potential for generating large tsunamis depend on the slide process. Among the world's largest submarine landslides is the Storegga Slide that generated an ocean-wide catastrophic tsunami, while no traces of a tsunami generated from the similar and nearby Trænadjupet Slide have been found. Previous models for ... -
Reconstructing the holocene. Benthic foraminifera as a proxy for the paleoceonography of the nordic seas
(Master thesis; Mastergradsoppgave, 2017-08-01)The benthic foraminifera of two marine sediment cores were studied as a proxy for paleoenvironment reconstructions throughout the Late to Early Holocene. The two cores were sampled in different localities to allow a spatial comparison of changing environments in the Nordic Seas and sampled for benthic foraminiferal assemblages, grain size, IRD, sortable silts and benthic foraminifera isotopes. While ... -
Removal of methane through hydrological, microbial, and geochemical processes in the shallow sediments of pockmarks along eastern Vestnesa Ridge (Svalbard)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016)The recent discovery of methane seeps in the Arctic region requires a better understanding of the fate of methane in marine sediments if we are to understand the contributions of methane to Arctic ecosystems and climate change. To further this goal, we analyze pore water data from five pockmarks along eastern Vestnesa Ridge, a sediment drift northwest of Svalbard, to quantify the consumption ... -
Structural and metamorphic implications of the final emplacement of the Lyngen Nappe
(Master thesis; Mastergradsoppgave, 2017-06-15)The Lyngen Nappe, an allochthonous unit of the Northern Norwegian Caledonides, consists of Greenschist-facies rocks overlying Amphibolite- to Granulite-facies rocks in the Nordmannvik Nappe. The lower-grade metamorphism seen in the Lyngen rocks juxtaposes higher-grade rocks both above and below. The nature and origin of this metamorphic break is investigated, specifically in the sheared rock units ... -
Stress distribution calculations through a snow slab of varying hardness. Comparison with stability evaluation in the field
(Master thesis; Mastergradsoppgave, 2017-05-05)Field observations are the main tools for assessing the snow stability concerning dry snow slab avalanche release. Often, theoretical studies cannot directly be translated into useful information for avalanche recreationists and forecasters in the field, and vice versa; field observations are not always objective and quantifiable for theoretical studies. Moreover, numerical models often oversimplify ... -
Geomorfologisk og strukturgeologisk undersøking av ustabile skråningar og skredavsettingar. Regional analyse av fjellområdet mellom Tromsøysundet og Ullsfjorden -Troms, Norge.
(Master thesis; Mastergradsoppgave, 2017-05-15)Samandrag Troms er det fylket i landet med flest registrerte ustabile fjellsider. Ved å kartlegga større områder for ustabile fjellparti og historiske skred, kan ein gjera ei regional analyse. Dette kan bidra til å forstå dei styrande faktorane for utrasing i eit regionalt perspektiv. Denne avhandlinga omhandlar hovudsakleg geomorfologi, og er skreve parallelt med Andreas Grumstad som har omtala ... -
Reconstruction of late Holocene paleoenvironment in Kongsfjorden, West Spitsbergen. Based on analysis of benthic foraminifera
(Master thesis; Mastergradsoppgave, 2017-05-15)The benthic foraminiferal fauna of two marine sediment records from the Kongsfjorden Trough and the inner part of Kongsfjorden were analyzed to reconstruct the paleoenvironmental development throughout the last ~ 2000 years. A generally cold period is evident in both records, lasting from ~ 700 to 1400 CE at the Kongsfjorden Trough and from ~ 350 to 1200 CE in the inner part of Kongsfjorden, with ... -
Paleoceanographic Development in Nordfjord, North East Greenland, During the Mid- and Late Holocene
(Master thesis; Mastergradsoppgave, 2017-05-15)Sediment core HH13-012GC-TUNU, retrieved from Nordfjord, North-East Greenland, has been investigated in order to reconstruct the paleoceanographic development during the mid- and late Holocene. Nordfjord is one of three tributary fjords to Kaiser Franz Joseph Fjord, and Waltershausen Gletcher is located at its head. The fjord system is largely influenced by the Eastern Greenland Current. Most of ... -
Processing and interpretation of the Svyatogor 2016 high-resolution P-Cable 3D seismic dataset. Investigating the dynamics of a sub-seabed gas hydrate system with a potential abiotic methane source
(Master thesis; Mastergradsoppgave, 2017-06-01)A new high-resolution P-Cable 3D seismic dataset was acquired in July 2016 targeting a seafloor pockmark cluster at the northern end of Svyatogor Ridge, offshore west Svalbard. The processing and interpretation of this dataset formed the primary focus of this thesis. The seismic processing sequence was designed to enhance the signal-to-noise ratio of the data while preserving the useful signal ... -
Exploratory data analysis of flexural waves in Arctic fjord ice seismic data
(Master thesis; Mastergradsoppgave, 2017-05-14)A seismic source on floating ice induces flexural waves in the ice layer. An exploratory data analysis of Arctic fjord ice seismic data is performed for the purpose of identifying and studying characteristics of flexural waves and other related wave modes. Both geophone and hydrophone data are examined with the purpose of studying ice properties from ice wave behavior. Power spectral density estimates ... -
Glacial history and geomorphology of Trygghamna, western Svalbard
(Master thesis; Mastergradsoppgave, 2017-05-15)This study investigates Trygghamna, a small fjord on the western coast of Spitsbergen, Svalbard. In order to investigate its glacial history, high-resolution aerial images and swath bathymetry are used to produce a detailed geomorphological map of the area, with a focus on the Neoglacial extent of the three largest glaciers in the fjord, Protektor-, Harriet- and Kjerulfbreen. The landforms are ...
