28 results on '"Rydningen, Tom Arne"'
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2. Seabed morphology and sedimentary processes on high-gradient trough mouth fans offshore Troms, northern Norway
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Rydningen, Tom Arne, Laberg, Jan Sverre, and Kolstad, Vidar
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- 2015
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3. A High Arctic inner shelf–fjord system from the Last Glacial Maximum to the present: Bessel Fjord and southwest Dove Bugt, northeastern Greenland.
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Zoller, Kevin, Laberg, Jan Sverre, Rydningen, Tom Arne, Husum, Katrine, and Forwick, Matthias
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LAST Glacial Maximum ,FJORDS ,GREENLAND ice ,WATERSHEDS ,ICE caps - Abstract
The Greenland Ice Sheet (GrIS) responds rapidly to the present climate; therefore, its response to the predicted future warming is of concern. To learn more about the impact of future climatic warming on the ice sheet, decoding its behavior during past periods of warmer than present climate is important. However, due to the scarcity of marine studies reconstructing ice sheet conditions on the Northeast Greenland shelf and adjacent fjords, the timing of the deglaciation over marine regions and its connection to forcing factors remain poorly constrained. This includes data collected in fjords that encompass the Holocene thermal maximum (HTM), a period in which the climate was warmer than it is at present. This paper aims to use new bathymetric data and the analysis of sediment gravity cores to enhance our understanding of ice dynamics of the GrIS in a fjord and inner shelf environment as well as give insight into the timing of deglaciation and provide a palaeoenvironmental reconstruction of southwestern Dove Bugt and Bessel Fjord since the Last Glacial Maximum (LGM). North–south-oriented glacial lineations and the absence of pronounced moraines in southwest Dove Bugt, an inner continental shelf embayment (trough), suggest the southwards and offshore flow of Storstrømmen, the southern branch of the Northeast Greenland Ice Stream (NEGIS). Sedimentological data suggest that an ice body, theorized to be the NEGIS, may have retreated from the region slightly before ∼ 11.4 cal ka BP. The seabed morphology of Bessel Fjord, a fjord terminating in southern Dove Bugt, includes numerous basins separated by thresholds. The position of basin thresholds, which include some recessional moraines, suggest that the GrIS had undergone multiple halts or readvances during deglaciation, likely during one of the cold events identified in the Greenland Summit temperature records. A minimum age of 7.1 cal ka BP is proposed for the retreat of ice through the fjord to or west of its present-day position in the Bessel Fjord catchment area. This suggests that the GrIS retreated from the marine realm in Early Holocene, around the onset of the HTM in this region, a period when the mean July temperature was at least 2–3 ∘ C higher than at present and remained at or west of this onshore position for the remainder of the Holocene. The transition from predominantly mud to muddy sand layers in a mid-fjord core at ∼ 4 cal ka BP may be the result of increased sediment input from nearby and growing ice caps. This shift may suggest that in the Late Holocene (Meghalayan), a period characterized by a temperature drop to modern values, ice caps in Bessel Fjord probably fluctuated with greater sensitivity to climatic conditions than the northeastern sector of the GrIS. [ABSTRACT FROM AUTHOR]
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- 2023
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4. Hammerfest Basin Composite Tectono-Sedimentary Element
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Henriksen, Erik, Kvamme, L., and Rydningen, Tom Arne
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The Hammerfest Basin is an E -W trending graben located between the Loppa High and the Finnmark Platform in the southern part of the Norwegian Barents Sea. Mainly siliciclastic strata of Carboniferous to Cenozoic age cover the Caledonian basement and have a total estimated thickness of 5-8 km. The basin evolved through several tectonic phases: the Carboniferous rifting, Late Jurassic rifting, the opening of the Atlantic Ocean, Oligocene reorganisation of plate movements and postglacial isostatic rebound. An E-W trending dome in the centre of the basin developed during the main extensional tectonic event in Late Jurassic. Horst structures represent the main hydrocarbon traps. Erosional channels on the flanks of the basin represent entry points for Lower Cretaceous sands. For the rest of the Cretaceous and Cenozoic intervals no significant reservoir sands are expected. The first exploration well in the Barents Sea in 1980 was located in the Hammerfest basin, and by 2019 a total of 45 wells had been drilled in the basin where 34 are classified as exploration wells. The result is 18 oil and gas discoveries, which gives a discovery rate of 53%. Two fields are now in production: the Snøhvit gas-condensate fields and the Goliat oil field. A total of 340 Msm3 (2140 Mbbl) recoverable oil equivalents have been discovered. For the middle Jurassic Play, the yet-to-find potential may be around 50 Msm3, distributed in several small structures in the basin. Following the oil discovery in the Middle Triassic interval in the Goliat structure, and because several of the previously drilled structures only penetrated the Jurassic and the uppermost Triassic section, considerable exploration potential may exist in the deeper Triassic interval in structures with the best reservoir facies. Stratigraphic traps of Cretaceous age may have a moderate petroleum potential, with excellent reservoirs encountered along the flank of the basin. Exploration potential may also exist in Upper Permian sandstones along the southern and eastern flanks of the basin. However, in large parts of the basin, the remaining potential is in the deep structures and hence is gas prone.
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- 2021
5. Last glacial ice sheet dynamics offshore NE Greenland – a case study from Store Koldewey Trough
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Olsen, Ingrid Leirvik, primary, Rydningen, Tom Arne, additional, Forwick, Matthias, additional, Laberg, Jan Sverre, additional, and Husum, Katrine, additional
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- 2020
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6. Relief preservation of a polar deep-sea channel system: the INBIS Channel (NW Barents Sea, Arctic)
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Rui, L., Rebesco, Michele, Casamor, J. L., Laberg, Jan Sverre, Rydningen, Tom Arne, Caburlotto, Andrea, Forwick, Matthias, Urgeles, Roger, Accettella, Daniela, Lucchi, Renata G., Delbono, Ivana, Barsanti, Mattia, Demarte, Maurizio, and Ivaldi, Roberta
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34th International Association of Sedimentologists (IAS) Meeting of Sedimentology, Sedimentology to face societal challenges on risk, resources and record of the past, 10-13 September 2019, Rome
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- 2019
7. Reviewing the Cenozoic Net Erosion of the Barents Sea Shelf
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Lasabuda, Amando Putra Ersaid, Laberg, Jan Sverre, Knutsen, Stig-Morten, and Rydningen, Tom Arne
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VDP::Mathematics and natural science: 400::Geosciences: 450 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 - Abstract
Presentation at the conference "Vinterkonferansen", 7. - 9.01.19, Bergen, arranged by NGF (Norsk Geologisk forening). https://www.geologi.no/konferanser/vinterkonferanser/item/947-vk19.
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- 2019
8. Cenozoic Erosion of the Barents Sea Shelf, Norwegian Arctic: A Review
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Lasabuda, Amando Putra Ersaid, Laberg, Jan Sverre, Knutsen, Stig-Morten, and Rydningen, Tom Arne
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VDP::Mathematics and natural science: 400::Geosciences: 450::Quaternary geology, glaciology: 465 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Kvartærgeologi, glasiologi: 465 - Abstract
The circum North Atlantic-Arctic continental margin and adjacent land areas have experienced several episodes of uplift and erosion during the Cenozoic. A series of efforts quantifying this erosion for the Barents Sea shelf, where the Arctic shelf is at its widest and deepest have been done since the early 90’s using different methods. As the seismic and well database have expanded considerably, our understanding of the Cenozoic evolution of this climatic sensitive and hydrocarbon prospective area has improved. This review includes a comparison of results from different methods (e.g. the mass balance technique,shale compaction, apatite fission track, sandstone diagenesis, and seismic velocities). The Cenozoic erosion is divided into a pre-glacial and a glacial erosion. The pre-glacial erosion is related to the early Cenozoic tectonics and riftflank uplift due to the onset of rifting, shear, and compression followed by sea-floor spreading between Norway and Greenland, whereas the glacial erosion occurred during the late Cenozoic Northern Hemisphere Glaciations when grounded ice sheets repeatedly covered the Barents Sea shelf. The different methods generally show the same order of magnitude of erosion for the major source areas in the Barents Sea, i.e. northern Norway, the Loppa High, the Stappen High, Svalbard, and from the northern Barents Sea margin. Furthermore, we compare sediment load and size of drainage area from various settings and different periods. For similar size of drainage area, sediment load for glacial period is generally higher than for the pre-glacial one. Our review shows that the ratio between the Cenozoic pre-glacial and glacial sedimentation along this part of the Arctic margin is ~40%, ~50%, and ~70% for the southwestern, northwestern, and the northern Barents Sea, respectively. Thus, there is a N-S trend of increasing pre-glacial erosion of the Barents Sea shelf, whereas an W-E trend of increasing erosion is inferred for the glacial period. Future directions of research in refining the erosion estimates and better understanding the mechanisms of uplift and erosion will be addressed.
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- 2018
9. Depicting a high-latitude channel system: the INBIS Channel (NW Barents Sea)
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Rui, L., Rebesco, Michele, Casamor, J. L., Laberg, Jan Sverre, Rydningen, Tom Arne, Caburlotto, Andrea, Forwick, Matthias, Urgeles, Roger, Accettella, Daniela, Madrussani, Gianni, Demarte, Maurizio, Ivaldi, Roberta, and Lucchi, Renata G.
- Abstract
European Geosciences Union (EGU) General Assembly 2018, 8-13 April 2018, Vienna, Austria.-- 1 page, The INBIS (Interfan Bear Island and Storfjorden) Channel System is a rare example of deep-sea channel on andbeyond a glaciated continental margin. This channel system is located between the Bear Island and Kveithola-Storfjorden Trough Mouth Fans on the SW Barents Sea continental margin. A new compilation of bathymetry datashows that a series of 40 gullies, about 150-600 m wide and with incision depth of 10-60 m, incises the upperpart of the continental slope. These merge and increase in size downslope, transit into larger tributary channels andconverge into the INBIS Channel. The fringes of the INBIS tributary channels are buried below glacigenic debrisflows originating from the upper slope and shelf of the adjacent Trough-Mouth Fans during glacial maxima. Thissuggests that the INBIS Channel was not generated primarily by mass flows released at the mouth of the troughs.We infer that this gully-dominated part of the INBIS Channel System developed mainly in interglacial periodsfrom dense water cascading from the continental shelf and meltwaters. This gully-dominated part was relativelyprotected, by its location to the west of Bear Island, from recurrent glacigenic debris flows allowing meltwaters tocontinuously increase gullies (and channels) dimensions during interglacial periods
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- 2018
10. Late Cenozoic Erosion Estimates for the Northern Barents Sea: Quantifying Glacial Sediment Input to the Arctic Ocean
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Lasabuda, Amando, primary, Geissler, Wolfram H., additional, Laberg, Jan Sverre, additional, Knutsen, Stig-Morten, additional, Rydningen, Tom Arne, additional, and Berglar, Kai, additional
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- 2018
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11. Chronology and extent of the Lofoten–Vesterålen sector of the Scandinavian Ice Sheet from 26 to 16 cal. ka BP
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Vorren, Tore O., primary, Rydningen, Tom Arne, additional, Baeten, Nicole J., additional, and Laberg, Jan Sverre, additional
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- 2015
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12. Inter-trough glacial landforms on the outermost NE Greenland shelf – preliminary results.
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Laberg, Jan Sverre, Rydningen, Tom Arne, Olsen, Ingrid L., Forwick, Matthias, and Husum, Katrine
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GLACIAL landforms , *GREENLAND ice , *LAST Glacial Maximum , *ICE sheets , *SEDIMENT analysis , *GLACIOLOGY - Abstract
Today the Arctic is undergoing far-reaching changes with rising air and sea-water temperatures, and rapidly decreasing glaciers and ice sheets. In order to model future changes of the ice sheet-ocean-atmosphere climate system, it is urgent to obtain more knowledge on the glacier dynamics of the Greenland Ice Sheet. Very little is known about the past evolution of the eastern sector of this ice sheet, e.g. it has not been established where its maximum position was during the Last Glacial Maximum (LGM). Furthermore, neither ice dynamics, sediment production by subglacial erosion or timing and nature of ice recession from the shelf is established. In this study, we have investigated the outermost part of the northeastern Greenland continental shelf. This is the widest shelf surrounding Greenland, with a shelf edge located more than 200 km off the coastline. Here, the shelf morphology comprises two large troughs (Norske Trough and the Westwind Trough) separated by a shallow bank complex (Belgica Bank, Northwind Shoal and the AWI Bank). Previous studies differ strongly on where this sector of the Greenland Ice Sheet reached its maximum position during the LGM. The studies point to positions from the inner shelf, mid-shelf or the shelf edge with the largest uncertainty related to the area of the shallow bank complex. During favorable sea-ice conditions in 2017, a ~130 km2 area on the outermost part of the shelf was surveyed by multi-beam echo-sounder and a sub-bottom profiler (Chirp). Close to the shelf break, the data displays part of a shelf-break parallel ridge that is heavily scoured by icebergs. The ridge is c. 30 m high, up to 9 km wide and with a steep western (proximal) and a gentler eastern (distal) slope. Compared to the recessional moraines reported from elsewhere in this area (Arndt et al., 2017), this feature is wider and higher, and its shape resembles a grounding-zone wedge identified in the nearby Norske Trough. Thus, we tentatively suggest that the observed ridge is also a grounding zone wedge formed at the grounding line of an ice sheet or ice cap reaching the outermost shelf. Part of a second ridge is seen approx. 10 km west of (inside) this ridge, implying a dynamic ice front with several halts or readvances during the retreat from the outer shelf. The age of these features remains to be determined, and this will be part of the future analysis of the sediment cores obtained in the study area. [ABSTRACT FROM AUTHOR]
- Published
- 2019
13. The deglaciation of the NW Barents Sea – new insights from swath-bathymetry and sub-bottom profiler data from east of the Svalbard archipelago.
- Author
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Rydningen, Tom Arne, Eilertsen, Vårin Trælvik, Forwick, Matthias, Husum, Katrine, Lasabuda, Amando, Laberg, Jan Sverre, and Ninnemann, Ulysses Silas
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GLACIAL landforms , *GLACIAL melting , *ICE sheet thawing , *SEA ice , *ICE sheets , *LAST Glacial Maximum - Abstract
With the decay of marine-based ice sheets observed today, e.g. in Antarctica and Greenland, there is a pressing need also for an improved understanding of marine paleo-ice sheets and their decay, as they provide critical constraints for a better understanding of the dynamics of modern ice sheets and their future behavior.Here we present new multi-beam swath-bathymetry and high-resolution Topas seismic data from the NW Barents Sea acquired during the Nansen Legacy (https://arvenetternansen.com/) Paleo-cruise in 2018, which provide new insights on the deglaciation history of the marine based Svalbard-Barents Sea Ice Sheet. Previous multi-beam data from the straits and troughs east of the Svalbard archipelago provided unclear or even conflicting evidence of full-glacial flow; i) eastwards, through the Erik Eriksen Strait and its eastward continuation, terminating in the Franz Victoria Trough, and ii) northwards through the Kvitøya Trough (Dowdeswell et al., 2010; Hogan et al., 2010).The new data provide evidence of a dynamic ice-sheet retreat during the deglaciation of the Erik Eriksen Strait and its eastern extension. A succession of superposing transverse ridges with a zig-zag like morphology characterize the eastern part of the mapped area. These ridges are interpreted to be recessional push-moraines, resulting from several smaller re-advances of the ice front during overall retreat through this part of the strait. To the west, ridges are buried by a ~40 m high and 20 km long sedimentary wedge, characterized by a smooth surface. The internal seismic configuration of the wedge is transparent. This sediment accumulation is interpreted to be a grounding zone wedge that likely formed during a major eastward oriented re-advance of the Svalbard-Barents Sea Ice Sheet during the deglaciation, burying some of the older recessional push-moraines. Thus, the eastward flow previously identified may be due to a major re-advance during the deglaciation rather than formed during full-glacial conditions.A ~3 msec thick layer of acoustically transparent sediments covering the grounding zone wedge and the recessional push-moraines, has been ground-truthed by gravity cores, both in front (east) of, and on top of the wedge. Radiocarbon dating will provide a minimum age for the formation of the glacial landforms, and thus add to our knowledge on the timing and dynamics of the retreat of this marine-based sector of the Svalbard-Barents Sea Ice Sheet following the Last Glacial Maximum, and this will enable improved modelling of this marine-based ice sheet.References:Dowdeswell, J.A., Hogan, K.A., Evans, J., Noormets, R., Ó Cofaigh, C., and Ottesen, D. (2010). Past ice-sheet flow east of Svalbard inferred from streamlined subglacial landforms. Geology, 38(2), 163-166.Hogan, K.A., Dowdeswell, J.A., Noormets, R., Evans, J., Cofaigh, C.Ó., and Jakobsson, M. (2010). Submarine landforms and ice-sheet flow in the Kvitøya Trough, northwestern Barents Sea. Quaternary Science Reviews, 29(25), 3545-3562. [ABSTRACT FROM AUTHOR]
- Published
- 2019
14. Depicting a high-latitude channel system: the INBIS Channel (NW Barents Sea).
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Rui, Leonardo, Rebesco, Michele, Casamor, José Luis, Laberg, Jan Sverre, Rydningen, Tom Arne, Caburlotto, Andrea, Forwick, Matthias, Urgeles, Roger, Accettella, Daniela, Madrussani, Gianni, Demarte, Maurizio, Ivaldi, Roberta, and Lucchi, Renata Giulia
- Published
- 2018
15. Late Cenozoic development of the mid-Norwegian continental margin – a study of the Naust Formation based on 3D-seismic data
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Lundegaard, Marius, Rydningen, Tom Arne, and Laberg, Jan Sverre
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VDP::Mathematics and natural science: 400::Geosciences: 450 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 ,GEO-3900 - Abstract
The late Cenozoic evolution of the outer continental shelf and slope on the northern part of the mid-Norwegian margin is studied using 3D seismic data. The late Cenozoic stratigraphy is subdivided into four main seismic units: unit A (oldest) to D and correlated to the established stratigraphic framework of the Naust Formation, where the oldest unit in this study correlates to the upper part of Naust unit A. The internal seismic signature of the units and the geomorphology of the unit boundaries form the basis for reconstructing the margin evolution. Palaeo-troughs and mega-scale glacial lineations (MSGLs) observed on buried shelf horizons suggest that fast-flowing ice streams drained from the Scandinavian mainland, traversed the shelf within Trænadjupet and Sklinnadjupet troughs, and reached the shelf break. Consequently, the palaeo-slope prograded westwards as downslope processes build out the margin. Based on seismic facies and geophysical attributes, the slope sediments were predominantly deposited by debris flows, but turbidity currents have also occurred. Large amount of glacial till was subglacially transported and deposited on the outer shelf and upper slope, before the sediments became unstable and redistributed downslope by gravity driven processes. The sediment distribution of the area suggests that both Trænadjupet and Sklinnadjupet troughs have been active during the glaciations; however, Sklinnadjupet Trough has been the main source of sediment during deposition of Naust A, U, S and T. Iceberg plough marks on all the buried surfaces testify to free-floating icebergs of sizes capable of eroding the outer shelf and upper slope. The Norwegian Atlantic Current was active during the margin buildout, as suggested by along slope drifting iceberg directions and the presence of the Nyk Drift on the slope.
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- 2020
16. Upper Triassic to lower Cretaceous tectonostratigraphic development of the Barents Sea South East
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Kristiansen, Ådne Frostad, Knutsen, Stig-Morten, Rydningen, Tom Arne, and Heiberg, Vegard
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VDP::Mathematics and natural science: 400::Geosciences: 450::Petroleum geology and petroleum geophysics: 464 ,GEO-3900 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Petroleumsgeologi og -geofysikk: 464 - Abstract
The aim of this study is to investigate the tectonic- and evolutionary differences between major structural elements of the Barents Sea South East (BSSE) during the uppermost Triassic to lower Cretaceous. The study area comprises the following structural elements: the Bjarmeland- and Finnmark platforms, the Nordkapp- and Tiddlybanken basins, the Signalhorn-, Haapet- and Veslekari domes and the Fedynsky High. Interpretation of seismic 2D- and well-data from the exploration well 7435/12-1 have provided the stratigraphic framework on the uppermost Triassic to lower Cretaceous, represented by the Realgrunnen Subgroup (late Norian to Bajocian), the Fuglen Formation (Callovian to Oxfordian) and the Hekkingen Formation (late Oxfordian to Tithonian). Thickness variations, and seismic stratigraphy as reflection geometries and terminations were applied to identify structural events such as uplift, subsidence and periods of erosion. Insight in the tectono-stratigraphic evolution of the Barents Sea South East have been provided by variations in the thickness and termination patterns of the uppermost Triassic to lower Cretaceous units. This study suggests a late Norian to Bajocian (represented by the Realgrunnen Subgroup) elevation of the Fedynsky High, Finnmark Platform, Veslekari- and Signalhorn domes. During the same period, a relatively stable platform configuration was valid for the Bjarmeland Platform and northern section of the Finnmark Platform, and concurrent basin configuration of the Nordkapp Basin, what today is the Haapet Dome and the area northeast of the dome structure. The structural trends valid for the late Norian to Bajocian continued into the Callovian to Oxfordian (represented by the Fuglen Formation), excluding the Haapet Dome, Bjarmeland Platform and north part of the Finnmark Platform in which the former experienced uplift and the two latter experienced subsidence during this period. The tectono-stratigraphic evolution of the Callovian to Oxfordian persisted through the late Oxfordian to Tithonian, accompanied by a rise in relative sea-level (represented by the Hekkingen Formation), in addition to subsidence of the Tiddlybanken Basin. Late Norian to Tithonian structuring of the BSSE are suggested to be linked to the possible reactivation of deep lineaments by the final upthrusting of the Novaya Zemlya (Late Triassic – Early Jurassic) and also the tectonic events that influenced the NE Atlantic rifting (Late Jurassic – Early Cretaceous) and later opening
- Published
- 2020
17. Last Glacial Maximum – Holocene palaeoenvironment in Bessel Fjord and southwestern Dove Bugt, Northeast Greenland
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Zoller, Kevin Michael, Laberg, Jan Sverre, Rydningen, Tom Arne, Husum, Katrine, and Forwick, Matthias
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VDP::Mathematics and natural science: 400::Geosciences: 450::Marine geology: 466 ,VDP::Mathematics and natural science: 400::Geosciences: 450::Sedimentology: 456 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 ,GEO-3900 ,VDP::Mathematics and natural science: 400::Geosciences: 450::Quaternary geology, glaciology: 465 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Sedimentologi: 456 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Kvartærgeologi, glasiologi: 465 - Abstract
Marine studies reconstructing ice sheet conditions on the Northeast Greenland shelf and adjacent fjords since the Last Glacial Maximum (LGM) are sparse. As a result, the timing and origin of the deglaciation of the ice sheet over marine areas is not well constrained. This thesis aims to improve our understanding of the LGM, deglaciation, and Holocene ice dynamics of the Greenland Ice Sheet (GrIS) near the southern outlet of the Northeast Greenland Ice Stream (NGIS), as well as reconstruct the palaeoenvironment of this region since the LGM. Here, swath bathymetry data and the multi-proxy analysis of three sediment gravity cores from southwestern Dove Bugt and Bessel Fjord were integrated. Dove Bugt is an embayment that is positioned to the east of Storstrømmen, the southern outlet of the NGIS. Bessel Fjord is a W-E oriented fjord that lies south of Storstrømmen and is connected to southern Dove Bugt via the Store Bælt sound. Bathymetric analysis of Dove Bugt revealed north-south oriented streamlined landforms which have been interpreted as the product of a fast-flowing, topographically bound branch of the NGIS that flowed southwards during the LGM. The sedimentology of a gravity core from southwestern Dove Bugt suggests that the NGIS may have retreat from the region around 11,190 cal. yr. BP, in conformity with previous onshore results. The presence of only a few, small retreat moraines implies that the deglaciation was rapid but may have had brief intervals of halting and/or readvancement. Sedimentation during the remainder of the Holocene is attributed to input from local ice caps and glaciers as well as mass wasting processes. The bathymetry of Bessel Fjord reveals several basins and sub-basin that are separated by basin thresholds. The configuration of geomorphic features suggests that glacial ice may have conformed to the topography during ice expansion and reached the outer fjord. The position of recessional moraines suggests that ice had undergone multiple halts and/or readvances and was topographically bound during deglaciation. Sediments from a gravity core collected in the inner fjord reflect a gradual transition from ice proximal to ice distal settings and an absence of glacial ice after 7,160 cal. yr. BP. A gravity core collected from a mid-fjord basin contains a transition from mud to muddy sand layers at ~4,000 yr. BP, which is believed to be the result of increased sediment input from nearby ice caps. This suggests that local ice caps in Bessel Fjord may have fluctuated with greater sensitivity to changing climatic conditions than the GrIS.
- Published
- 2020
18. Isdynamikk i tre mindre fjord-trausystemer langs Finnmarkskysten
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Skjeldnes, Marie Elise Planting, Rydningen, Tom Arne, Laberg, Jan Sverre, and Corner, Geoffrey
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VDP::Mathematics and natural science: 400::Geosciences: 450::Marine geology: 466 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 ,EOM-3901 - Abstract
Multistråle batymetriske data og seismiske profiler fra den vestlige kysten av Finnmark er analysert med formålet om å rekonstruere dynamikken til det Fennoskandiske Isdekket gjennom siste glasiale maksimum, og påfølgende deglasiasjon. Fokuset har vært på tre prograderende kiler i forlengelsen av de glasiale trauene Rolvsøy-, Hjelmsøy- og Måsøytrauet. En seismisk stratigrafi er definert med tre hovedenheter; A, B og C. Enhet A og B representerer de prograderende kilene med interne klinoformer utbyggende fra sørøst mot nordvest. Enhet C er karakterisert av en transparent seismisk signatur tilskrevet bunnmorene fra siste istids maksimum. En utviklingsmodell for studieområdet er presentert med en tidlig (glasi-) fluvial fase, etterfulgt av faser med større isdekker oscillerende ved munningen til trauene. Siste fase representeres av et isdekke som strekker seg over hele studieområdet og Barentshavet. Glasiale landformer er kartlagt i trauene og på bankene langs kysten, og disse er brukt til å rekonstruere dynamikken til isdekket under siste glasiale maksimum og deglasiasjonen. Strømlinjeformede landformer i trauene vitner om hurtigstrømmede ismasser under siste glasiale maksimum, mens fravær av disse tyder på mer saktestrømmende og passive ismasser på bankene. Deglasiasjonen beskrives som hurtig sammenlignet med nærliggende fjordsystem, og startet trolig i trauene da det forekommer dypere vanndyp og glasiale lineasjoner er bevart. På bankene observeres det to til tre mulig fremrykk/opphold av isdekket. Disse ismassene har trolig drenert fra lokale isdomer på de ytterste øyene langs Finnmarkskysten. Observasjonene i denne oppgaven er korrelert med eksisterende dateringer på land. Risviktrinnet (16-15 000 kal år BP) er tentativt antatt å representere starten på deglasiasjonen i trauene og tilskrives frontavsetningene i Hjelmsøy- og Måsøytrauet. Studieområdet var sannsynligvis isfritt under Ytre Porsangertrinnet (14 000 kal år BP), da en ikke observerer flere randtrinn lengre inn i trauene.
- Published
- 2019
19. Salt movements in three provinces in the southwestern Barents Sea: development, timing, and implications of regional structural differences
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Thorsen, Truls, Knutsen, Stig-Morten, Rydningen, Tom Arne, and Krogh Johansen, Sondre
- Subjects
Nordkappbassenget ,Svalis Dome ,Norvarg Dome ,Salttektonikk ,Samson Dome ,Salt tectonics ,Nordkapp Basin ,Samsondomen ,VDP::Mathematics and natural science: 400::Geosciences: 450::Petroleum geology and petroleum geophysics: 464 ,GEO-3900 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Petroleumsgeologi og -geofysikk: 464 ,Svalisdomen ,Norvargdomen - Abstract
This study has investigated salt movements in the Nordkapp Basin, on the Loppa High (Svalis Dome) and on the Bjarmeland Platform (Samson- and Norvarg domes). The aim is to discuss how differences in salt growth potentially relates to the structural evolution of - and differences between - these three provinces. Evaluation of seismic 2D- and 3D data together with well correlation, allowed a regional stratigraphic framework to be established for the Permian-Quaternary succession. Four stratigraphic units were defined: Lower Triassic, Lower to Middle Triassic, Middle Triassic-Jurassic and Cretaceous-recent. Thickness variations and reflection configurations within these units, together with salt morphology, documented the timing of salt growth. In the Nordkapp Basin, several phases of salt growth occurred throughout the Triassic, a period usually referred to as tectonically quiet in the southwestern Barents Sea. Extensional forces locally lead to subsidence and faulting/steepening of the basin margins. A regional extensional event lead to renewed salt growth during the Cretaceous, before Cenozoic regional compression squeezed the diapirs, resulting in a final growth phase. At the Svalis Dome, a salt pillow grew during the Early to Middle Triassic-Jurassic. Later uplift and erosion of the dome resulted in renewed growth and diapirism. Little or no salt movements are observed on the Samson- and Norvarg domes during the Mesozoic, but Cenozoic compression appears to have mobilized the salt. The main differences in salt growth between the three provinces seem to relate to the different structural settings; in the Nordkapp Basin, diapirs grew already in the Triassic possibly due to extensional forces in and adjacent to the basin. On the Svalis Dome, the salt growth seems to relate to a large degree of uplift of the Loppa High. At the Bjarmeland Platform, a late initial growth stage reflects a tectonically stable environment until Cenozoic regional compression mobilized the salt.
- Published
- 2019
20. Seismic sequence analysis and petroleum system indicators at the Oligocene-Miocene level in the southern North Sea
- Author
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Poulsen, Johanne Schøning, Rydningen, Tom Arne, and Brunstad, Harald
- Subjects
VDP::Mathematics and natural science: 400::Geosciences: 450::Petroleum geology and petroleum geophysics: 464 ,GEO-3900 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Petroleumsgeologi og -geofysikk: 464 - Abstract
A thorough review of the Oligocene-Miocene stratigraphic evolution and depositional environments in the Norwegian part of the southern North Sea is presented and considered alongside observations of petroleum system indicators, from seismic-, core- and well-data. The reconstructed paleo-environments show a trend of fluctuating eustatic sea-levels, controlled by basin subsidence and uplift of the Fennoscandian Platform in the north, coupled with growth and melt of the Antarctic Ice Sheet. Stages of rising sea-level are reflected by low-angle, sigmoidal clinoforms with ascending shelf-break trajectories deposited simultaneously to rapid basin subsidence. Periods of a relative fall in sea-level are characterized by complex-oblique clinoform stacking patterns, with a distal displacement of the shelf and descending shelf-break trajectories. Falling stage system tracts are dominated by the evolution and progradation of complex channel systems and erosion of the exposed shelf. Lowstand system tracts are recognized where coarser, sand-rich material was deposited towards the distal basin margins. The results provide new insight on the subsurface drainage system, as well as an evaluation of a potential Oligocene reservoir rock, the Vade Formation, which in general showed good reservoir properties. This work proposes an updated depositional model for the sandstone, with a newly defined lateral reach, extending beyond the previously established boundaries of this formation. The suggested model describing the petroleum system favours lateral drainage with migration focused sub-horizontally through the permeable Vade Formation which is capped by transgressive, sealing lithologies. Here a persuasive correlation to a Jurassic source rock, the Mandal Formation, is outlined, providing a tentative basis on which to endorse a thermogenic origin of the observed hydrocarbon indications with long distance lateral migration enabling accumulations to form far from the petroleum kitchen area. A differential entrapment model alongside potential leakage and well-information, provides an explanation for the dry wells adjacent to possible hydrocarbon accumulations in the region. The evaluation of the petroleum system sheds new light on the potential for several hydrocarbon filled structures in the subsurface of the Norwegian southern North Sea.
- Published
- 2019
21. Late Cenozoic erosion in the SW Barents Sea, and its influence on salt movement
- Author
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Martinsen, Birgitta Saue, Knutsen, Stig-Morten, Johansen, Sondre, and Rydningen, Tom Arne
- Subjects
VDP::Mathematics and natural science: 400::Geosciences: 450 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 ,GEO-3900 - Abstract
The late Cenozoic evolution of the southwestern Barents Sea shelf includes periods of uplift, erosion and glaciations. This part of the stratigraphy has been studied using 2D and 3D seismic data, with emphasis on the interplay between uplift, erosion and glaciations and salt movement. The study area comprises the Svalis, Samson and Norvarg domes and the Nordkapp Basin, where halokinesis has been a major influence on the tectonostratigraphic evolution. The study includes systemization and categorization of the timing of salt activity relative to the erosion of the shelf, in the Nordkapp Basin, and on the Svalis, Samson and Norvarg domes. Very late to almost recent salt movement has occurred within some of the diapirs in the Nordkapp Basin and the Svalis Dome, evidenced by uplift of the Upper Regional Unconformity (URU) surface and the seafloor above the salt. Furthermore, the study reveals significant local variations in salt movement of the diapirs in the Nordkapp Basin, with a trend of more late salt movement towards the northeast. This is possibly attributed to a larger original salt thickness in this part of the basin compared to in the southwest. A mini-basin filled with glacigenic sediments is found adjacent to the Svalis Dome, and this is assumed to be a result of a combination of deeper glacial erosion of less resistant strata on the Loppa High, and less exposure to erosion due to the continuous salt rise and elevation of the adjacent dome. The Norvarg and Samson domes are not found to be influenced by late Cenozoic salt movement, which is attributed to factors such as original salt thickness, overburden strength and early Cenozoic erosion. Spatial variations in lithology due to salt-related doming and faulting is assumed to have influenced both the pre-glacial and later glacial erosion of the Norvarg Dome during the Cenozoic. Overall, the relationship between salt diapirism, erosion and glacial influence is found to be complex. The structural elements within the study area have experienced different pre-Cenozoic evolutions and have been exposed to varying degrees of erosion and also phases of grounded glaciers. The halokinetic history of the structural elements is also different, causing the salt structures within the study area to have different responses to the late Cenozoic uplift, erosion and glaciation of the shelf.
- Published
- 2019
22. 3D-seismic interpretation of the glacial deposits in the outer Ingøydjupet area, SW Barents Sea. Ice sheet dynamics reconstructed from glacial landforms
- Author
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Strømme, Kristine, Rydningen, Tom Arne, Martens, Iver, Brunstad, Harald, and Lie, Jan Erik
- Subjects
VDP::Mathematics and natural science: 400::Geosciences: 450 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 ,GEO-3900 - Abstract
The late Quaternary evolution of the outer Ingøydjupet area (SW Barents Sea) is studied using a merge of conventional 3D-seismic cubes and a new generation of high-resolution 3D-seismic (TopSeis). The glacigenic sequence is subdivided into five main seismic units: unit A1 (oldest) to A5. These are separated by six glacially eroded boundaries: the Upper Regional Unconformity (URU), intra-glacial horizons (Q1-Q4) and the seafloor. A correlation to established seismic stratigraphies suggests that the units A1-A3 were deposited during middle Pleistocene and A4-A5 during late Pleistocene. The internal seismic signature of the units is described and the geomorphologies of the main surfaces are mapped. This forms the basis for a reconstruction of the ice-sheet dynamics and depositional environment during the late Quaternary evolution of the outer Ingøydjupet area. Mega-scale glacial lineations and troughs observed on the paleo-surfaces confirm that fast-flowing ice streams have occupied and eroded the outer Ingøydjupet area at least five times since the formation of the URU. The orientation of the lineations suggests that both the Ingøydjupet- and the Bjørnøyrenna Ice Streams have been active in the area during these glaciations. Buried sediment blocks, which are interpreted to have been entrained, transported and re-deposited by the paleo-ice streams indicate that the ice streams underwent phases of basal freezing. The recessional features on the URU and the seafloor suggest complex and dynamic retreats of the ice sheet following glacial maxima, where repeated halts and re-advances characterized the deglaciation. The intra-glacial horizons on the other hand show evidence of rather rapid ice sheet retreats, where mega-scale glacial lineations are preserved on the paleo-surfaces.
- Published
- 2019
23. Sedimentary processes and paleoenvironment reconstructions in fjords comprising the Bergsfjord peninsula, Northern Norway
- Author
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Kollsgård, Christine Tømmervik, Forwick, Matthias, and Rydningen, Tom Arne
- Subjects
VDP::Mathematics and natural science: 400::Geosciences: 450::Marine geology: 466 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 ,GEO-3900 - Abstract
Low-resolution bathymetry, high-resolution seismic data (chirp) and multi-proxy analyses of three sediment gravity cores were integrated to study sedimentary processes with the purpose of reconstructing paleoenvironments in the three north Norwegian fjords Øksfjorden, Bergsfjorden and Jøkelfjorden since the last glacial. These three fjords are located on the Bergsfjorden peninsula and surround the ice cap Øksfjordjøkelen. The multi-proxy analyses of the sediment cores included measurements of the physical properties (e.g. wet-bulk density, magnetic susceptibility), X-radiography, X-ray fluorescence (XRF) core scanning, grain-size distribution analyses and visual descriptions of the sediment cores. The results suggest that four sedimentary processes occurred in the fjords: glacier-proximal sedimentation with repeated changes of physical conditions in a glacimarine environment, suspension settling in an open-marine environment with occasional ice rafting, mass wasting, as well as deltaic processes. Furthermore, the results suggest that Bergsfjorden was deglaciated prior to c. 11,090 cal. yrs. BP and that a large-scale mass-transport event took place shortly before this time. The glacier Øksfjordjøkelen has terminated in Jøkelfjorden during the last at least 8.7 ka cal. yrs. BP. An advance of Svartfjelljøkelen and Øksfjordjøkelen occurred presumably around 8.2 ka cal. yrs. BP. Glacial activity was very reduced or absent in Bergsfjorden between 7.3 and 5.0 ka cal. yrs. BP in Bergsfjorden. Relatively steady sedimentary environments are observed after 4.2 ka cal. yrs. BP in Bergsfjorden, 5.1 ka cal. yrs. BP Øksfjorden and 5.0 ka cal. yrs. BP in Jøkelfjorden.
- Published
- 2018
24. Use of 2D-seismic data and available wells to investigate the source potential of the Palaeozoic interval in the Loppa High area, SW Barents Sea
- Author
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Hetland, Asbjørn, Martens, Iver, and Rydningen, Tom Arne
- Subjects
GEO-3900 ,VDP::Mathematics and natural science: 400::Geosciences: 450::Petroleum geology and petroleum geophysics: 464 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Petroleumsgeologi og -geofysikk: 464 - Abstract
While most established plays in the Barents Sea have occurred in the Mesozoic, the Alta and Gohta discoveries prove a new carbonate play concept, with a source rock that does not stem from the Jurassic. Based on depositional environment and TOC values from the Palaeozoic interval a source rock with Top Ørn as its bottom and Top Røye as its top was interpreted. Basin modelling carried out on this potential source rock concludes that the Palaeozoic interval in the Loppa High area have a good source potential. A total of 30 different models have been carried out and three highlighted models, the P10, P50 and P90 model all shows evidence of good maturity ranges (ranging from 0.5 %Ro to 1.5 %Ro) and generation potential.
- Published
- 2018
25. Sedimentary environment and seismic anomalies of the upper Brygge and Kai formations on the northern part of the Mid-Norwegian Continental Shelf
- Author
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Krokmyrdal, Suchada Yaiying, Laberg, Jan Sverre, Rydningen, Tom Arne, and Rafaelsen, Bjarne
- Subjects
VDP::Mathematics and natural science: 400::Geosciences: 450::Marine geology: 466 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 ,GEO-3900 - Abstract
The sedimentary environment and seismic anomalies of the upper Brygge and Kai formations on the northern part of the Mid-Norwegian Continental Shelf is analysed from 3D seismic data and the exploration well 6604/2-1. This was done in order to give a better understanding of the paleo-climatic development in the period before the establishment of the large-scale ice sheets of the Northern Hemisphere, and to provides a better insight in the relationship to fluid and/or gas migration from different levels in the subsurface. Based on a seismic stratigraphic analysis, correlation to well logs and previous work in the area, five seismic sub-units were recognized: B1-B2 of the upper Brygge Formation (pre-mid Miocene), and K1-K3 of the Kai Formation (mid Miocene-early Pliocene). The geometry and internal seismic reflection facies, as well as the morphology of buried surfaces have been described and discussed in relation to the depositional environment and the development of the ocean circulation pattern in the Norwegian Sea. Based on the seismic analysis, a signature characteristic of contourite deposits was identified in the study area. Mounded elongated contourite drifts formed by ocean current-controlled deposition was observed in the upper Brygge Formation. After a period of tectonic uplift in the mid-Miocene, local anticlinal highs were developed, including the Helland-Hansen and Modgunn arches. These features probably played a major role in controlling the flow pattern of the ocean currents, associated with the deposition of the Kai Formation sediments. The ocean currents were entering the study area from the south, resulting in erosion in the southern part and deposition in the northern part. During the late Miocene-early Pliocene time, a change of the ocean current pattern led to erosion in the northern part, and deposition in the southeastern part of the study area. Seismic attribute analysis revealed seismic anomalies, including circular forms. These are classified into three types, based on their stratigraphic distribution and dimensions, and association with fluid and/or gas migration from deep to shallow strata. The cluster of high amplitude anomalies, including bright spots and acoustic pipes indicate fluid flow originating from deep stratigraphic levels to terminate at or near the top of the Kai Formation. Paleo-pockmarks resulted from fluid migration along major faults from a deep thermogenic source, and eventually fluid expulsion from the polygonal fault system.
- Published
- 2017
26. Depositional environments of the Upper Triassic Snadd Formation on the Loppa High, SW Barents Sea
- Author
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Johansen, Stian André and Rydningen, Tom Arne
- Subjects
Loppa High ,VDP::Mathematics and natural science: 400::Geosciences: 450::Stratigraphy and paleontology: 461 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Stratigrafi og paleontologi: 461 ,Depositional environment ,EOM-3901 - Abstract
This thesis has focused on the depositional environments of the Upper Triassic Snadd Formation. This formation covers the time-period Ladinian to early Norian with multiple marine regressions and transgressions, resulting in depositional environments ranging from offshore marine shelf to a coastal plain. A 3D seismic dataset and its correlating well have been studied and a refined seismic stratigraphic framework for the Snadd Formation is proposed. The area of investigation is located at the border between the Loppa High, the Bjarmeland Platform and the Hammerfest Basin. The study defines five time-stratigraphic units within the formation, bounded by regional flooding surfaces. Depositional features observed on seismic data, demonstrate distinct depositional environments within each unit. This thesis show that a marine setting dominates the lower units (Ladinian to middle Carnian), with three shorter periods of marine regressions exposing the study area to marginal marine and coastal plain processes. In the upper units (middle Carnian to early Norian), a marine regression shifts the dominating environment from marine to a coastal plain. The deposition of the Snadd Formation ends by a marine transgression, known as the early Norian flooding event.
- Published
- 2016
27. The Cenozoic pre-glacial sedimentary environment of the SW Barents Sea continental margin – Lofoten Basin
- Author
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Høgseth, Gert Vidar, Laberg, Jan Sverre, and Rydningen, Tom Arne
- Subjects
VDP::Mathematics and natural science: 400::Geosciences: 450::Marine geology: 466 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 ,GEO-3900 - Abstract
2D seismic data have been analysed to study the Cenozoic pre-glacial sedimentary environment on the southwest Barents Sea margin and the Lofoten Basin. Based on a seismic stratigraphic analysis and correlation to previous work in the area, the pre-glacial seismic unit G0 has been subdivided into four. The four units have been described and discussed with regards to the geometry and internal seismic facies, and the sedimentary processes and depositional environment dominating during the deposition of the seismic units have been outlined.
- Published
- 2016
28. Seabed depressions in the Ingøydjupet Trough and their relation to buried canyons on the Loppa High, Barents Sea
- Author
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Prytz, Richard, Rydningen, Tom Arne, Martens, Iver, and Myrvang, Jim
- Subjects
VDP::Mathematics and natural science: 400::Geosciences: 450::Marine geology: 466 ,VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 ,EOM-3901 - Abstract
Large seabed depressions in the Ingøydjupet Trough have previously been interpreted to be formed by sub-glacial melt-water. However, fluid migration and gas expulsion occur over large parts of the Barents Sea, which are frequently associated with seabed depressions. This thesis studies how the seabed depressions are related to sub-surface canyons on the southern part of the Loppa High, SW Barents Sea. The canyons are located stratigraphically below the seabed depressions, and high-amplitude zones at the canyon crests indicate accumulation of gas. Migration of fluids seems to take place along the canyon flanks, and the canyons and their infills have been mapped out in order to infer the distribution of shallow gas and their relation to the seabed depressions. Uplift and erosion have influenced the fluid flow system several times since the formation of the canyons. The final phase was related to glacial isostatic adjustment causing the gas to expand and build up pressure before eruption and seepage of shallow gas took place. Severe erosion further caused the seismic unit S2 to the absent in the southwestern parts of the study area. The thickness of S2 appears to affect the distribution of depressions and fluid migration, as it acts as an impermeable barrier where it is present and thus prevents fluids to reach the seabed and form depressions. The large seabed depressions above the canyons occur in areas where S2 is not present, which suggests that shallow gas is indeed a major contributor to the seafloor topography.
- Published
- 2016
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