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dc.contributor.advisorMienert, Jürgen
dc.contributor.authorRajan, Anupama
dc.date.accessioned2013-05-08T13:56:09Z
dc.date.available2013-05-08T13:56:09Z
dc.date.issued2013-02-06
dc.description.abstractThe thesis consists of four parts and its four main objectives are: (1) to establish a potential link between serpentinization beneath a young sedimented-ocean ridge and carbon release and gas hydrate formation directly above it, (2) to understand the coexistence of free gas and gas-hydrate and to image the geophysical evidence for a geologically controlled gas hydrate, fluid migration pathway and seabed expulsion system, (3) to image the active fluid flow migration path-networks from deep hydrocarbon sources and to assess the distribution of shallow gas accumulation, and (4) to determine in detail the seismic velocity structure of the regions close to the landward limit of hydrate stability zone. The methodology implemented to realize this aims was achieved by integrating 3D seismic imaging, 1D velocity modeling to 2D seismic imaging and bathymetric and oceanographic data mapping. This PhD thesis presents results from four articles that glean into the fluid flow and gas-hydrate systems of the NW-Svalbard and SW-Barents Sea margins. The important results found during this research are: (1) new evidence for carbon release from the deep-seated source rock through the sediments above diapirism and methane capture in the inferred areas of serpentinization at the Knipovich Ridge, (2) new geophysical evidence for gas migration and geologically controlled gas hydrate system offshore NW-Svalbard, where several existing glacigenic debris flow units, which are spatially confined and influence gas migration pathways and hence, the location of gas leakage zones at the seafloor and (3) first findings of the formation of “tilted” bottom-simulating reflector in the SW-Barents Sea. They have formed due to variations in fluid flux along regions of deep-seated fault complexes causing a change in heat flow. The data also provides new evidence for the connection of deep-hydrocarbon and shallow gas hydrate, where existing fault complexes apparently act as pathways for the upward migration of fluids.en
dc.description.doctoraltypeph.d.en
dc.description.popularabstractGas hydrate/free gas reservoirs could be a new future energy resource or if released from shallow sub-surface by natural processes a concern for the environment. The gas /or fluid expulsion at continental margins induce wide range of processes including not only mud volcanism, mud diapirism and gas flares but also continuously seeping methane-rich fluids leading to cold vent site. Seepage of fluids frequently leads to precipitation of authigenic carbonates in the more porous layers that modify sedimentary processes along the margin, and these fluids constitute the energy source for a number of diverse and complex ecosystems. In general the aim of the research was to characterize the fluid flow and gas-hydrate systems of the NW-Svalbard and SW-Barents Sea margins. The methodology implemented to realize this aims was achieved by 3D seismic imaging, 1D velocity modeling to 2D seismic imaging and bathymetric and oceanographic data mapping. The important results found during this research gives new evidence for carbon release from the deep-seated source rock through the sediments above diapirism and methane capture in the areas of serpentinization at the Knipovich Ridge, gas migration and geologically controlled gas hydrate system offshore NW-Svalbard and the connection of deep-hydrocarbon and shallow gas hydrate reservoirs and the unique formation of “tilted” bottom-simulating reflector in the SW-Barents Sea, where existing fault complexes apparently act as pathways for the upward migration of fluids.en
dc.description.sponsorshipTrainee School in Arctic Marine Geology and Geophysics (AMGG),University of Tromsøen
dc.descriptionPapers 2, and 4 of this thesis are not available in Munin: <br/>2. Rajan, A., J. Mienert, and S. Bünz: 'Acoustic evidence for a gas migration and release system in Arctic glaciated continental margins offshore NW-Svalbard', Marine and Petroleum Geology (2012), vol.32(1):36-49. Available at <a href=http://dx.doi.org/10.1016/j.marpetgeo.2011.12.008>http://dx.doi.org/10.1016/j.marpetgeo.2011.12.008</a> <br/>3. Anupama Rajan, Stefan Bünz, Jürgen Mienert and. Andrew J. Smith: 'Tilted bottomsimulating reflectors (TBSRs) provide evidence for active fluid flow from deep hydrocarbon sources in the SW-Barents Sea' (manuscript) <br/>4. Anupama Rajan, Tim A. Minshull and Jürgen Mienert: 'Heterogeneous distribution of gashydrate and free gas in glaciated sediments of the NW-Svalbard continental margin inferred from changes in compressional wave velocity' (manuscript).en
dc.identifier.isbn978-82-8236-089-0
dc.identifier.isbn978-82-8236-088-3
dc.identifier.urihttps://hdl.handle.net/10037/5149
dc.identifier.urnURN:NBN:no-uit_munin_4861
dc.language.isoengen
dc.publisherUniversitetet i Tromsøen
dc.publisherUniversity of Tromsøen
dc.rights.accessRightsopenAccess
dc.rights.holderCopyright 2013 The Author(s)
dc.subject.courseIDDOKTOR-004en
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450::Solid earth physics: 451en
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Faste jords fysikk: 451en
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450::Oceanography: 452en
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Oseanografi: 452en
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450::Petroleum geology and petroleum geophysics: 464en
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Petroleumsgeologi og -geofysikk: 464en
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450::Marine geology: 466en
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466en
dc.titleGeophysical characterizations of fluid flow and gas-hydrate systems of the NW-Svalbard and SW-Barents Sea marginsen
dc.typeDoctoral thesisen
dc.typeDoktorgradsavhandlingen


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