302 research outputs found
Fysiske og biogeokjemiske prosesser : klimaendringer i norsk Arktis : NorACIA delutredning 2
No full textFysiske og biogeokjemiske prosesser : klimaendringer i norsk Arktis : NorACIA delutredning 2
No full textLithostratigraphic lexicon of Svalbard: upper Palaeozoic to Quaternary bedrock / Stratigrafisk komité for Svalbard (SKS)
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Analyse av paleozoiske forkastninger og deres relasjon til devon-karbon avsetninger langs Sassenfjorden og Tempelfjorden, Svalbard, basert på multiverktøy land og fjord-datasett.
No full textLedd i Billefjordforkastningssonen kan man finne på begge sidene av Sassenfjorden. Disse leddene er forsøkt knyttet sammen i denne analysen. Batymetriske data fra Sassenfjordens fjordbunn avslører rygger og andre strukturer som har en spennende innvirkning på de seismiske dataene.
Hovedfunnene i denne analysen er kategorisert i tre kategorier. Kategori 1 omtaler en obskur sone på seismikken som kan relateres direkte til Billefjordforkastningssonen med steile forkastninger og oppknust berggrunn som ikke lar seg godt avbilde på seismikk.
Funn som er plassert i kategori 2 er tolket til å være mesozoiske magmatiske ganger som skaper amplitudeanomalier og fremstående strukturer. Med lokalt skarpe kontraster i intern hastigheter relativt til sedimentære bergarter kan det være at de også påvirker seismikken i området mer enn antatt ved første øyekast.
Konturer og strukturer i fjorden som gir en brå endring i vanndyp er plassert i kategori 3. Det er også en skarp kontrast i intern hastighet mellom vann og sedimentære bergarter, noe som tilsynelatende påvirker store og små deler av den seismiske avbildningen. Det kan se ut som fjorder sammenfaller med synklinaler og odder med antiklinaler. Disse syn- og antiklinalene er ikke observerbare på land
Structural analysis along seismic profiles trough late-Paleozoic deposits in Billefjorden and Sassenfjorden, Svalbard and their relation to the Billefjorden Fault Zone
No full textThe focus of this thesis is structural analysis of the Billefjorden Fault Zone astride Billefjorden and Sassenfjorden in Spitsbergen, with the use of seismic interpretation combined/aided by geological and bathymetric maps, field observations and well data. The aim is to describe structures and the tectonic development of the study area. The focus is on large tectonic events from Devonian to Palaeogene.
The Billefjorden Fault Zone was described in detail by Harland et al. (1974). Since then, many studies have been made on the fault zone, with much focus on along-strike changes and a suggested reactivation history. Most published work is based on land observations from Austfjorden to Pyramiden. Much less work has been done on the offshore domain of the fault zone.
Marine seismic data from Billefjorden and Sassenfjorden were available for this thesis. In order to identify stratigraphic units in the seismic profiles, terrestrial seismics are used in combination with well data and a velocity survey from Reindalen. Furthermore, geological maps, published works and bathymetry are used for structural interpretation.
The seismic data are of very poor quality. This presents a challenge in locating stratigraphic units and identifying structures. No well-tie is available in the study area. Therefore, a well in Reindalen is used. The distance from the well to the study area is problematic since only part of the stratigraphy overlap. Another problem are significant geological changes along the tie-line. The problems with poor data quality is partially solved by combining the seismic data with geological maps and bathymetry.
The result is a number of interpreted seismic lines and bathymetry. The interpretation includes stratigraphic division and structural elements such as faults, folds, horst, graben and basins. Based on the seismic interpretation and bathymetry a suggested tectonic development is presented. The structures described in Billefjorden and Sassenfjorden span form post-Caledonian orogenic collapse, Devonian convergence, Carboniferous basin development, Cretaceous intrusive events and Palaeogene convergence.
Furthermore, a model for the offshore continuation of the BFZ in Billefjorden and Sassenfjorden is presented. The model differs from other published work in regard to the southward extent of the Balliolbreen Fault and Odellfjellet Fault. In this thesis it is suggested that the fault array is preserved between Pyramiden and the south coast of Sassenfjorden. An important along-strike change is the narrowing of a fault-bound horst that is bound by the two faults.
Analysis of the seismic data and bathymetry also suggest the existence of two NW-SE trending lineaments along Sassenfjorden. The two lineaments are suggested faults which have not been mapped previously
Review of Islands of the Arctic, by Julian Dowdeswell & Michael Hambrey
No full textThis is a well illustrated introductory book about the islands of the Arctic
Notes on the stratigraphy, extent and tectonic implications of the Minkinfjellet Basin, Middle Carboniferous of central Spitsbergen
No full textA part of the Carboniferous basin stratigraphy, the clastic to carbonaceous Minkinfjellet “Member” of the Nordenskioldbreen Formation in Central Spitsbergen, is deposited in an asymmetric basin structure (here referred to as the Minkinfjellet Basin), similar to the underlying Ebbadalen Formation. The western boundary -situated within the Billcfjorden Fault Zone -has probably been a little farther east than during deposition of the Ebbadalen strata. The thickness attains ca. 350 m in central parts of the basin, and the strata strongly attenuates to the east and south. The base and top are interpreted as low-angle stratigraphical unconformities. The boundary with the overlying Cadcllfjellet Member of the Nordenskioldbreen Formation is locally disrupted by carbonate breccias of suggested earthquake origin. Formation rank is suggested for the sedimentary succession of the Minkinfjellet basin
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