Trias Nord – Utviklingen av Barentshavet i Trias

• Olaussen, Snorre; Grundvåg, Sten-Andreas; Senger, Kim; Anell, Ingrid; Betlem, Peter & Birchall, Thomas [Vis alle 15 forfattere av denne artikkelen] (2023). Svalbard Composite Tectono-Sedimentary Element, Barents Sea”. Geological Society of London Memoirs. ISSN 0435-4052. 57. doi: 10.1144/M57-2021-36. Fulltekst i vitenarkiv Vis sammendrag

  The Svalbard Composite Tectono-Sedimentary Element (SCTSE) is located on the northwestern corner of the Barents Shelf and comprises a Carboniferous–Pleistocene sedimentary succession. Due to Cenozoic uplift, the succession is subaerially exposed in the Svalbard archipelago. The oldest parts of the succession consist of Carboniferous–Permian mixed siliciclastic, carbonate and evaporite, and spiculitic sediments that developed during multiple phases of extension. The majority of the Mesozoic succession is composed of siliciclastic deposits formed in sag basins and continental platforms. Episodes of Late Jurassic and Early Cretaceous contraction are evident in the eastern part of thearchipelago and in nearby offshore areas. Differential uplift related to the opening of the Amerasian Basin and the Cretaceous emplacement of the High Arctic Large Igneous Province created a major hiatus spanning from the Late Cretaceous and early Danian throughout the SvalbardCTSE. The West Spitsbergen Fold and Thrust Belt and the associated foreland basin in central Spitsbergen (Central Tertiary Basin) formed as a response to the Eurekan Orogeny and the progressive northward opening of the North Atlantic during the Paleogene. This event was followed by the formation of yet another major hiatus spanning the Oligocene–Pliocene. Multiple reservoir and source-rock units exposed in Svalbardprovide analogues to the prolific offshore acreages in the SW Barents Sea, and are important for the de-risking of plays and prospects. However, the archipelago itself is regarded as a high-risk acreage for petroleum exploration. This is due to Paleogene contraction and late Neogene uplift of the western and central parts in particular. There is an absence of mature source rocks in the east, and the entire region is subjected to strict environmental protection

• Olaussen, Snorre; Grundvåg, Sten-Andreas; Senger, Kim; Anell, Ingrid; Betlem, Peter & Birchall, Thomas [Vis alle 15 forfattere av denne artikkelen] (2022). The Svalbard Carboniferous to Cenozoic Composite Tectono-Stratigraphic Element. Geological Society of London Memoirs. ISSN 0435-4052. 57(1). doi: 10.1144/M57-2021-36. Fulltekst i vitenarkiv Vis sammendrag

  The Svalbard Composite Tectono-Stratigraphic Element is located on the north-western corner of the Barents Shelf and comprises a Carboniferous to Pleistocene sedimentary succession. Due to Cenozoic uplift the succession is subaerially exposed in the Svalbard archipelago. The oldest parts of the succession consist of Carboniferous to Permian mixed siliciclastic, carbonate and evaporite and spiculitic sediments that developed during multiple phases of extension. The majority of the Mesozoic succession is composed of siliciclastic deposits formed in sag basins and continental platforms. Episodes of Late Jurassic and Early Cretaceous contraction are evident in the eastern partof the archipelago and in nearby offshore areas. Differential uplift related to the opening of the Amerasian Basin and the Cretaceous emplacement of the High Arctic Large Igneous Province created a major hiatus spanning from the Late Cretaceous and early Danian throughout the Svalbard Composite Tectono-Stratigraphic Element

• Smyrak-Sikora, Aleksandra; Osmundsen, Per Terje; Braathen, Alvar; Ogata, Kei; Anell, Ingrid Margareta & Mulrooney, Mark Joseph [Vis alle 7 forfattere av denne artikkelen] (2019). Architecture of growth basins in a tidally influenced, prodelta to delta-front setting: The Triassic succession of Kvalpynten, East Svalbard. Basin Research. ISSN 0950-091X. doi: 10.1111/bre.12410. Fulltekst i vitenarkiv Vis sammendrag

  World‐class examples of fault‐controlled growth basins with associated syn‐kinematic sedimentary fill are developed in Upper Triassic prodelta to delta‐front deposits exposed at Kvalpynten, SW Edgeøya in East Svalbard. They are interpreted to have interacted with north‐westerly progradation of a regional delta system. The syn‐kinematic successions consist of 4 to 5 coarsening‐upward units spanning from offshore mudstones to subtidal heterolithic bars and compound tidal dunes, which were blanketed by regional, post‐kinematic sandstone sheets deposited as laterally continuous, subaqueous tidal dune fields. The rate of growth faulting is reflected in the distribution of accommodation, which governs sedimentary architecture and stacking patterns within the coarsening‐upward units. Fully compartmentalized basins (12, 200–800 m wide and c. 150 m high grabens and half grabens) are characterized by syn‐kinematic sedimentary infill. These grabens and half‐grabens are separated by 60–150 m high horsts composed of pro‐delta to distal delta‐front mudstones. Grabens host tabular tidal dunes (sandwaves), whereas half‐grabens bound by listric faults (mainly south‐dipping) consist of wedge‐shaped, rotated strata with erosive boundaries proximal to the uplifted fault block crests. Heterolithic tidal bars (sand ridges) occur in narrow half‐grabens, showing migration oblique to the faults, up the dipslope. Structureless sandstone wedges and localized subaqueous slumps that formed in response to collapse of the block crests were only documented in half‐grabens. Late‐kinematic deposition during the final stages of faulting occurred in partly compartmentalized basins, filled with variably thick sets of continuous sandstone belts (compound tidal dunes).

• Buckley, Simon John; Ringdal, Kari; Naumann, Nicole; Dolva, Benjamin; Kurz, Tobias Herbert & Howell, John Anthony [Vis alle 7 forfattere av denne artikkelen] (2019). LIME: Software for 3-D visualization, interpretation, and communication of virtual geoscience models. Geosphere. 15(1), s. 222–235. doi: 10.1130/GES02002.1. Fulltekst i vitenarkiv Vis sammendrag

  The use of three-dimensional (3-D), photo-textured representations of topography from laser scanning and photogrammetry is becoming increasingly common across the geosciences. This rapid adoption is driven by recent innovations in acquisition hardware, software automation, and sensor platforms, including unmanned aerial vehicles. In addition, fusion of surface geometry with imaging sensors, such as multispectral, hyperspectral, thermal, and ground-based radar, and geophysical methods creates complex and visual data sets that provide a fundamental spatial framework to address open geoscience research questions. Despite the current ease of acquiring and processing 3-D photo-textured models, the accessibility of tools for analyzing and presenting data remains problematic, characterized by steep learning curves and custom solutions for individual geoscience applications. Interpretation and measurement is essential for quantitative analysis of 3-D data sets, and qualitative methods are valuable for presentation purposes, for planning, and in education. This contribution presents LIME, a lightweight and high-performance 3-D software for interpreting and co-visualizing 3-D models and related image data. The software allows measurement and interpretation via digitizing in the 3-D scene. In addition, it features novel data integration and visualization of 3-D topography with image sources such as logs and interpretation panels, supplementary wavelength imagery, geophysical data sets, and georeferenced maps and images. High-quality visual output can be generated for dissemination to aid researchers with communication of their results. The motivation and an overview of the software are described, illustrated by example usage scenarios from outcrop geology, multi-sensor data fusion, and geophysical-geospatial data integration.

• Haile, Beyene Girma; Czarniecka, Urszula; Xi, Kelai; Smyrak-Sikora, Aleksandra; Jahren, Jens & Braathen, Alvar [Vis alle 7 forfattere av denne artikkelen] (2019). Hydrothermally induced diagenesis: Evidence from shallow marine-deltaic sediments, Wilhelmøya, Svalbard. Geoscience Frontiers (GSF). ISSN 1674-9871. 10(2), s. 629–649. doi: 10.1016/j.gsf.2018.02.015. Fulltekst i vitenarkiv Vis sammendrag

  Sedimentary basins containing igneous intrusions within sedimentary reservoir units represent an important risk in petroleum exploration. The Upper Triassic to Lower Jurassic sediments at Wilhelmøya (Svalbard) contains reservoir heterogeneity as a result of sill emplacement and represent a unique case study to better understand the effect of magmatic intrusions on the general burial diagenesis of siliciclastic sediments. Sills develop contact metamorphic aureoles by conduction as presented in many earlier studies. However, there is significant impact of localized hydrothermal circulation systems affecting reservoir sediments at considerable distance from the sill intrusions. Dolerite sill intrusions in the studied area are of limited vertical extent (∼12 m thick), but created localized hydrothermal convection cells affecting sediments at considerable distance (more than five times the thickness of the sill) from the intrusions. We present evidence that the sedimentary sequence can be divided into two units: (1) the bulk poorly lithified sediment with a maximum burial temperature much lower than 60–70 °C, and (2) thinner intervals outside the contact zone that have experienced hydrothermal temperatures (around 140 °C). The main diagenetic alteration associated with normal burial diagenesis is minor mechanical plastic deformation of ductile grains such as mica. Mineral grain contacts show no evidence of pressure dissolution and the vitrinite reflectance suggests a maximum temperature of ∼40 °C. Contrary to this, part of the sediment, preferentially along calcite cemented flow baffles, show evidence of hydrothermal alteration. These hydrothermally altered sediment sections are characterized by recrystallized carbonate cemented intervals. Further, the hydrothermal solutions have resulted in localized sericitization (illitization) of feldspars, albitization of both K-feldspar and plagioclase and the formation of fibrous illite nucleated on kaolinite. These observations suggest hydrothermal alteration at T > 120–140 °C at distances considerably further away than expected from sill heat dissipation by conduction only, which commonly affect sediments about twice the thickness of the sill intrusion. We propose that carbonate-cemented sections acted as flow baffles already during the hydrothermal fluid mobility and controlled the migration pathways of the buoyant hot fluids. Significant hydrothermally induced diagenetic alterations affecting the porosity and hence reservoir quality was not noted in the noncarbonate-cemented reservoir intervals.

• Lord, Gareth Steven; Mørk, Mai Britt Engeness; Mørk, Atle & Olaussen, Snorre (2019). Sedimentology and petrography of the Svenskøya Formation on Hopen, Svalbard: an analogue to sandstone reservoirs in the Realgrunnen Subgroup. Polar Research. ISSN 0800-0395. 38. doi: 10.33265/polar.v38.3523. Fulltekst i vitenarkiv Vis sammendrag

  On the island of Hopen, in the Svalbard Archipelago, the Svenskøya Formation is a succession 35 m in thickness, consisting primarily of sandstone beds and forming the youngest strata exposed on the island. We present a sedimentological and petrographic study of the formation and compare the unit with its exposures on Wilhelmøya and in Kong Karls Land, Svalbard. We also compare the onshore characteristics of the Svenskøya Formation with those of the Tubåen Formation, its time-equivalent unit in the Sentralbanken area of the northern Barents Sea. On Hopen, the Svenskøya Formation is interpreted as representing coarse clastic sediments deposited in a fluvial to tidal setting, prior to being overlain by a thin interval composed of tidal channel and marine shale deposits. The unit sits atop the regional “Rhaetian Unconformity” and represents sediments deposited during a regressive system that terminates at a flooding surface representing a local transgression of the palaeo-coastline. Petrographic studies show the formation as being arkosic, both on Hopen and in the Sentralbanken area. The reservoir quality of sandstone samples recovered from Hopen is somewhat lower compared to sandstone reservoirs in the Sentralbanken area. We attribute this to greater effects of diagenesis in the Hopen area, which caused increased compaction, mineral dissolution and extensive precipitation of pore-filling clay minerals.

• Mulrooney, Mark Joseph; Larsen, Leif; Stappen, Jeroen Van; Rismyhr, Bjarte; Senger, Kim & Braathen, Alvar [Vis alle 10 forfattere av denne artikkelen] (2018). Fluid flow properties of the Wilhelmøya Subgroup, a potential unconventional CO2 storage unit in central Spitsbergen. Norwegian Journal of Geology. ISSN 2387-5844. 99(4), s. 85–116. doi: 10.17850/njg002. Fulltekst i vitenarkiv Vis sammendrag

  The Upper Triassic to Middle Jurassic Wilhelmøya Subgroup forms one of the more suitable reservoir units on the Norwegian Arctic archipelago of Svalbard. The target siliciclastic storage unit, which is encountered at approx. 670 m depth at the potential injection site in Adventdalen, central Spitsbergen, is a severely under-pressured (at least 35 bar), tight and compartmentalised reservoir with significant contribution of natural fractures to permeability. In this contribution, we characterise the 15–24 m-thick Wilhelmøya Subgroup storage unit using both borehole and outcrop data and present water-injection test results that indicate the presence of fluid-flow barriers and the generation of new, and propagation of pre-existing natural fractures during injection. Whole core samples from drillcores and outcrops were sampled for pore network characterisation and analysed using high-resolution X-ray computed tomography (Micro-CT). We demonstrate that heterogeneities such as structural discontinuities, igneous bodies and lateral facies variations, as examined in well core and equivalent outcrops, will strongly influence fluid flow in the target reservoir, both by steering and baffling fluid migration. Many of these heterogeneities are considered to be subseismic, and their detailed characterisation is important to predict subsurface CO2 storage potential and optimise injection strategy.

• Line, Lina Hedvig; Jahren, Jens & Hellevang, Helge (2018). Mechanical compaction in chlorite-coated sandstone reservoirs - Examples from Middle - Late Triassic channels in the southwestern Barents Sea. Marine and Petroleum Geology. ISSN 0264-8172. 96, s. 348–370. doi: 10.1016/j.marpetgeo.2018.05.025. Fulltekst i vitenarkiv Vis sammendrag

  The relationship between diagenetic evolution and reservoir quality in large-scale Middle – Late Triassic aged channel systems (up to 20 km wide) in the southwestern Barents Sea is investigated through core plug data, XRD, SEM- and modal analyses. The studied channel systems are likely sourced from the southeastern Uralide mountain range and are characterized by chemically unstable clastic sediment and well-developed, porosity-preserving chlorite coatings. Chlorite coatings occupy potential quartz nucleation sites on the framework grain surfaces and likely prevent significant chemical compaction in deeply buried sandstones. Porosity-reduction is believed to follow mechanical compaction trends of similar sandstone compositions. Modelling and prediction of porosity preservation in Middle - Late Triassic channel sandstones in the study area is therefore possible, if temperature histories and sandstone compositions are well constrained. The tidally influenced channel and fluvial-dominated channels in this study show significant variation in reservoir quality. These differences are found to be linked to amount of allogenic matrix and grain size, which significantly reduces the permeability in the tidally influenced channel. If seismic distinction between different channel types is impossible, the distribution of permeability is considered unpredictable. Chlorite coatings in the investigated channels are interpreted to be diagenetic overprints of a precursor clay phase, which appears to have a strong link to the Uralian provenance. Coating precursor emplacement likely occurs prior to significant burial, but the exact physical conditions enabling this process remain elusive without systematic laboratory and analogue studie

• Eide, Christian Haug; Muller, Reidar & Helland-Hansen, William (2018). Using climate to relate water-discharge and area in modern and ancient catchments. Sedimentology. ISSN 0037-0746. 65(4), s. 1378–1389. doi: 10.1111/sed.12426. Fulltekst i vitenarkiv Vis sammendrag

  Models relating sediment supply to catchment properties are important in order to use the geological record to deduce landscape evolution and interplay between tectonics and climate. Water-discharge (Qw) is an important factor in the widely used BQART-model of Syvitski and Milliman (2007), which relates sediment load to a set of measureable catchment parameters. Although many of the factors in this equation may be independently estimated with some degree of certainty in ancient systems, water-discharge (Qw) certainly cannot. An analysis of a world database of modern catchments (Milliman and Farnsworth, 2011) shows that the commonly applied equation relating catchment area (A) to water-discharge (Qw=0.075A0.8), does not predict water-discharge from catchment area well in many cases (R2=0.5 and an error spanning c. 3 orders-of-magnitude). This is because the method does not incorporate the effect of arid and wet climate on river water-discharge. The inclusion of climate-data into such estimations is an opportunity to refine these estimates, because generalized estimates of palaeoclimate can often be deduced on the basis of sedimentological data such as palaeosol types, mineralogy and palaeohydraulics. This paper investigates how the relationship between catchment area and river discharge vary with four runoff categories (arid, semiarid, humid, and wet) which are recognizable in the geological record, and modifies the coefficient and exponent of the abovementioned equation according to these classes. Our modified model yields improved results in relating discharge to catchment area (R2=0.95 and error spanning 1 order-of-magnitude) when core-, outcrop- or regional palaeoclimate reconstruction data are available in non-arid systems. Arid systems have an inherently variable water-discharge, and catchment area is less important as a control due to downstream losses. The model here is sufficient for many geological applications and makes it possible to include variations in catchment humidity in mass-flux estimates in ancient settings.

• Eide, Christian Haug; Schofield, Nick; Lecomte, Isabelle; Buckley, Simon John & Howell, John Anthony (2018). Seismic interpretation of sill complexes in sedimentary basins: Implications for the sub-sill imaging problem. Journal of the Geological Society. ISSN 0016-7649. 175(2), s. 193–209. doi: 10.1144/jgs2017-096. Fulltekst i vitenarkiv Vis sammendrag

  Application of 3D-seismic reflection-data to igneous systems in sedimentary basins has led to a revolution in the understanding of mafic sill-complexes. However, there is considerable uncertainty on how geometries and architecture of sill-complexes within the subsurface relates to those imaged in seismic reflection-data. To provide constraints on how sill-complexes in seismic data should be interpreted, we present synthetic seismograms generated from a seismic-scale (22x0.25 km) outcrop in East Greenland constrained by abundant field-data. This study highlights how overlying igneous rocks adversely affect imaging of underlying intrusions and rocks by decreasing seismic amplitude, frequency and making steeply dipping features near-impossible to image. Furthermore, seismic modelling in this study shows that, because of the high impedance contrast between siliciclastic host-rock and dolerites, very thin (1-5 m) intrusions should in principle be imaged in reflection-seismic data at 3 km depth. However, comparison with actual seismic data with well-data shows significant amounts of un-imaged sill intrusions, and this is likely due to limited seismic resolution, overburden complexity, inadequate velocity-models, and interference between reflections from closely spaced sills and sill-splays. Significant improvements to sill imaging and interpretation could be made by better predicting occurrence and geometry of sill intrusions and including these in velocity models.

• Ogata, Kei; Mulrooney, Mark; Braathen, Alvar; Maher, Harmon; Osmundsen, Per Terje & Anell, Ingrid Margareta [Vis alle 8 forfattere av denne artikkelen] (2018). Architecture, deformation style and petrophysical properties of growth fault systems: the Late Triassic deltaic succession of southern Edgeøya (East Svalbard). Basin Research. ISSN 0950-091X. 30(5), s. 1042–1073. doi: 10.1111/bre.12296. Fulltekst i vitenarkiv Vis sammendrag

  The Late Triassic outcrops on southern Edgeøya, East Svalbard, allow a multiscale study of syn‐sedimentary listric growth faults located in the prodelta region of a regional prograding system. At least three hierarchical orders of growth faults have been recognized, each showing different deformation mechanisms, styles and stratigraphic locations of the associated detachment interval. The faults, characterized by mutually influencing deformation envelopes over space‐time, generally show SW‐ to SE‐dipping directions, indicating a counter‐regional trend with respect to the inferred W‐NW directed progradation of the associated delta system. The down‐dip movement is accommodated by polyphase deformation, with the different fault architectural elements recording a time‐dependent transition from fluidal‐hydroplastic to ductile‐brittle deformation, which is also conceptually scale‐dependent, from the smaller‐ (3rd order) to the larger‐scale (1st order) end‐member faults respectively. A shift from distributed strain to strain localization towards the fault cores is observed at the meso to microscale (<1 mm), and in the variation in petrophysical parameters of the litho‐structural facies across and along the fault envelope, with bulk porosity, density, pore size and microcrack intensity varying accordingly to deformation and reworking intensity of inherited structural fabrics. The second‐ and third‐order listric fault nucleation points appear to be located above blind fault tip‐related monoclines involving cemented organic shales. Close to planar, through‐going, first‐order faults cut across this boundary, eventually connecting with other favourable lower‐hierarchy fault to create seismic‐scale fault zones similar to those imaged in the nearby offshore areas. The inferred large‐scale driving mechanisms for the first‐order faults are related to the combined effect of tectonic reactivation of deeper Palaeozoic structures in a far field stress regime due to the Uralide orogeny, and differential compaction associated with increased sand sedimentary input in a fine‐grained, water‐saturated, low‐accommodation, prodeltaic depositional environment. In synergy to this large‐scale picture, small‐scale causative factors favouring second‐ and third‐order faulting seem to be related to mechanical‐rheological instabilities related to localized shallow diagenesis and liquidization fronts.

• Braathen, Alvar; Midtkandal, Ivar; Mulrooney, Mark; Appleyard, Tyler Ross; Haile, Beyene Girma & Yperen, Anna Elisabeth van (2018). Growth-faults from delta collapse - structural and sedimentological investigation of the Last Chance delta, Ferron Sandstone, Utah. Basin Research. ISSN 0950-091X. 30(4), s. 688–707. doi: 10.1111/bre.12271. Fulltekst i vitenarkiv
• Olaussen, Snorre; Larssen, Geir Birger; Helland-Hansen, William; Johannessen, Erik P.; Nøttvedt, Arvid & Riis, Fridtjof [Vis alle 9 forfattere av denne artikkelen] (2018). Mesozoic strata of Kong Karls Land, Svalbard, Norway; a link to the northern Barents Sea basins and platforms. Norwegian Journal of Geology. ISSN 2387-5844. 98(4), s. 1–69. doi: 10.17850/njg98-4-06. Fulltekst i vitenarkiv
• Mulrooney, Mark; Rismyhr, Bjarte; Yenwongfai, Honore Dzekamelive; Leutscher, Johan; Olaussen, Snorre & Braathen, Alvar (2018). Impacts of small-scale faults on continental to coastal plain deposition: Evidence from the Realgrunnen Subgroup in the Goliat field, southwest Barents Sea, Norway. Marine and Petroleum Geology. ISSN 0264-8172. 95, s. 276–302. doi: 10.1016/j.marpetgeo.2018.04.023. Fulltekst i vitenarkiv Vis sammendrag

  In this study we synthesise sedimentological, fault, and Amplitude Versus Angle (AVA) analysis and propose that the Fruholmen and Tubåen formations (Realgrunnen Subgroup) are syn-kinematic deposits that record a previously undocumented early phase of Mesozoic rifting on the Troms-Finnmark fault Complex and within the Hammerfest Basin. The Realgrunnen Subgroup hosts one of two Triassic reservoirs currently being produced in the Goliat field. Here, the subgroup sits unconformably on top of the Storfjorden Subgroup (Carnian Snadd Formation). Away from the Goliat field, which is characterised by a periclinal anticline, the Realgrunnen Subgroup also comprises the Lower–Middle Jurassic Nordmela and Stø formations. Sedimentological analysis of six exploration wells reveals that the Fruholmen Formation was deposited in a prodelta to delta plain environment where tide-influenced and fluvial-dominated distributary channels are represented by clay/siltstones and very fine grained sandstones. The overlying Tubåen Formation is characterised by medium to very coarse-grained deposits (locally conglomeratic) and represents a widespread braid plain with localised alluvial fans. Displacement profiles of faults and along-fault thickness variations demonstrate that an immature fault system was active during deposition of the Realgrunnen Subgroup. A series of unconnected fault segments hosted isolated sub-basins and erosional catchment areas in their hanging and footwalls, respectively. An AVA attribute map generated from a 10 ms interval of the uppermost part of the subgroup reveals gross sand-prone depositional bodies, i.e., individual and amalgamated channels, (some of which show meandering geometries), ox-bow lakes and alluvial fans. Sand bodies frequently show elongate geometries parallel to faults indicative of syn-depositional fault-related subsidence. Driving mechanisms responsible for the Norian to Rhaetian event may relate to contemporaneous rejuvenation of the Fennoscandian hinterland, development of the Novaya Zemlya fold-and-thrust belt and/or the early Cimmerian tectonic phase in northern Europe.

• Haile, Beyene Girma; Klausen, Tore Grane; Czarniecka, Urszula; Xi, Kelai; Jahren, Jens & Hellevang, Helge (2018). How are diagenesis and reservoir quality linked to depositional facies? A deltaic succession, Edgeøya, Svalbard. Marine and Petroleum Geology. ISSN 0264-8172. 92, s. 519–546. doi: 10.1016/j.marpetgeo.2017.11.019. Fulltekst i vitenarkiv
• Haile, Beyene Girma; Klausen, Tore Grane; Jahren, Jens; Braathen, Alvar & Hellevang, Helge (2018). Thermal history of a Triassic sedimentary sequence verified by a multi-method approach: Edgeøya, Svalbard, Norway. Basin Research. ISSN 0950-091X. 30(6), s. 1075–1097. doi: 10.1111/bre.12292. Fulltekst i vitenarkiv
• Yenwongfai, Honore Dzekamelive; Mondol, Nazmul Haque; Lecomte, Isabelle; Faleide, Jan Inge & Leutscher, Johan (2018). Integrating facies-based Bayesian inversion and supervised machine learning for petro-facies characterization in the Snadd Formation of the Goliat Field, south-western Barents Sea. Geophysical Prospecting. ISSN 0016-8025. 67, s. 1020–1039. doi: 10.1111/1365-2478.12654. Fulltekst i vitenarkiv Vis sammendrag

  Seismic petro‐facies characterization in low net‐to‐gross reservoirs with poor reservoir properties such as the Snadd Formation in the Goliat field requires a multidisciplinary approach. This is especially important when the elastic properties of the desired petro‐facies significantly overlap. Pore fluid corrected endmember sand and shale depth trends have been used to generate stochastic forward models for different lithology and fluid combinations in order to assess the degree of separation of different petro‐facies. Subsequently, a spectral decomposition and blending of selected frequency volumes reveal some seismic fluvial geomorphological features. We then jointly inverted for impedance and facies within a Bayesian framework using facies‐dependent rock physics depth trends as input. The results from the inversion are then integrated into a supervised machine learning neural network for effective porosity discrimination. Probability density functions derived from stochastic forward modelling of endmember depth trends show a decreasing seismic fluid discrimination with depth. Spectral decomposition and blending of selected frequencies reveal a dominant NNE trend compared to the regional SE–NW pro‐gradational trend, and a local E–W trend potentially related to fault activity at branches of the Troms‐Finnmark Fault Complex. The facies‐based inversion captures the main reservoir facies within the limits of the seismic bandwidth. Meanwhile the effective porosity predictions from the multilayer feed forward neural network are consistent with the inverted facies model, and can be used to qualitatively highlight the cleanest regions within the inverted facies model. A combination of facies‐based inversion and neural network improves the seismic reservoir delineation of the Snadd Formation in the Goliat Field.

• Eide, Christian Haug; Klausen, Tore Grane; Katkov, Denis; Suslova, Anna & Helland-Hansen, William (2017). Linking an Early Triassic delta to antecedent topography: Source-to-sink study of the southwestern Barents Sea margin. Geological Society of America Bulletin. ISSN 0016-7606. 130(1-2), s. 263–283. doi: 10.1130/B31639.1. Fulltekst i vitenarkiv Vis sammendrag

  Present-day catchments adjacent to sedimentary basins may preserve geomorphic elements that have been active through long intervals of time. Relicts of ancient catchments in present-day landscapes may be investigated using mass-balance models and can give important information about upland landscape evolution and reservoir distribution in adjacent basins. However, such methods are in their infancy and are often difficult to apply in deep-time settings due to later landscape modification. The southern Barents Sea margin of N Norway and NW Russia is ideal for investigating source-to-sink models, because it has been subject to minor tectonic activity since the Carboniferous, and large parts have eluded significant Quaternary glacial erosion. A zone close to the present-day coast has likely acted as the boundary between basin and catchments since the Carboniferous. Around the Permian-Triassic transition, a large delta system started to prograde from the same area as the present-day largest river in the area, the Tana River, which has long been interpreted to show features indicating that it was developed prior to present-day topography. We performed a source-to-sink study of this ancient system in order to investigate potential linkages between present-day geomorphology and ancient deposits. We investigated the sediment load of the ancient delta using well, core, two-dimensional and three-dimensional seismic data, and digital elevation models to investigate the geomorphology of the onshore catchment and surrounding areas. Our results imply that the present-day Tana catchment was formed close to the Permian-Triassic transition, and that the Triassic delta system has much better reservoir properties compared to the rest of Triassic basin infill. This implies that landscapes may indeed preserve catchment geometries for extended periods of time, and it demonstrates that source-to-sink techniques can be instrumental in predicting the extent and quality of subsurface reservoirs.

• Klausen, Tore Grane; Muller, Reidar; Slama, Jiri; Olaussen, Snorre; Rismyhr, Bjarte & Helland-Hansen, William (2017). Depositional history of a condensed shallow marine reservoir succession: stratigraphy and detrital zircon geochronology of the Jurassic Stø Formation, Barents Sea. Journal of the Geological Society. ISSN 0016-7649. 175(1), s. 130–145. doi: 10.1144/jgs2017-024. Fulltekst i vitenarkiv
• Mulrooney, Mark; Leutscher, J & Braathen, Alvar (2017). A 3D structural analysis of the Goliat field, Barents Sea, Norway. Marine and Petroleum Geology. ISSN 0264-8172. 86, s. 192–212. doi: 10.1016/j.marpetgeo.2017.05.038. Fulltekst i vitenarkiv
• Maher, Harmon; Ogata, Kei & Braathen, Alvar (2017). Cone-in-cone and beef mineralization associated with Triassic growth basin faulting and shallow shale diagenesis, Edgeøya, Svalbard. Geological Magazine. ISSN 0016-7568. 154(2), s. 201–216. doi: 10.1017/S0016756815000886. Fulltekst i vitenarkiv Vis sammendrag

  Cone-in-cone (CIC) and beef (BF) carbonate lenses ornament detachment zone faults underlying Triassic growth basins on Edgeøya. Field relationships place CIC and BF growth as during early diagenesis and a transition from hydroplastic to a later brittle-style of faulting that is marked by coarser calcite veining. Deformation is constrained to have occurred at <300 m depth. Multiple models exist for CIC formation. For the Edgeøya example, textural analysis of thin-sections suggests that small tensile fractures and carbonate shell fragments nucleated development of calcite aggregates with CIC and BF morphology within unconsolidated to poorly consolidated sediment to form asymmetric antitaxial tensile aggregates subparallel to bedding and fault surfaces. The conical forms result from differential growth on stepped, cleavage-parallel faces of fibres facing host sediment, with preferential inclusion incorporation at inner corners. The preferred directions of calcite growth are attributed to local stresses and seepage flow associated with pore pressure gradients. Substantial framboidal pyrite in the sediments represents an early phase of microbially driven sulphate reduction, which may have induced calcite mineralization. The transition to brittle-style faulting was marked by development of deformation twins in CIC/BF fibres, and a transition to coarse, blocky calcite growth in relay arrays of steeply oriented microveins. This indicates local fault-related stresses substantially changed during shallow diagenesis and lithification, an evolution attributed to changing pore pressures, seepage forces and material moduli. Calcite mineralizations at Edgeøya track the very significant changes in mechanical properties and stress states that occur during synlithification deformation at very shallow crustal levels.

• Anell, Ingrid Margareta & Midtkandal, Ivar (2017). The quantifiable clinothem – types, shapes and geometric relationships in the Plio-Pleistocene Giant Foresets Formation, Taranaki Basin, New Zealand. Basin Research. ISSN 0950-091X. 29, s. 277–297. doi: 10.1111/bre.12149. Fulltekst i vitenarkiv
• Klausen, Tore Grane; Torland, Jonas Aas; Eide, Christian Haug; Alaei, Behzad; Olaussen, Snorre & Chiarella, Domenico (2017). Clinoform development and topset evolution in a mud-rich delta - the Middle Triassic Kobbe Formation, Norwegian Barents Sea. Sedimentology. ISSN 0037-0746. 65(4), s. 1132–1169. doi: 10.1111/sed.12417. Fulltekst i vitenarkiv Vis sammendrag

  Clinoform surfaces are routinely used to mark transitions from shallow waters to deep basins. This concept represents a valuable tool for screening potential reservoir intervals in frontier basins where limited data are available. Variations in the character of clinoform geometries and shoreline and shelf-edge trajectories are indicators of a range of different factors, such as palaeobathymetry, changes in relative sea-level and sediment supply. Applications of conceptual and generalized models might however lead to erroneous assumptions about the supply of coarse-grained material to the delta front and basin when superficial similarities between clinoform geometries are not treated holistically. The present study examines the mudstone-dominated Middle Triassic Kobbe Formation – a potential hydrocarbon reservoir interval in the Barents Sea, where prodeltaic to deltaic deposits can be examined in cores, well logs and two-dimensional and three-dimensional seismic data. Despite pronounced acoustic impedance contrast to the surrounding shale, channel belt networks are not observed close to the platform-edge in seismic datasets, even at maximum regressive stages. However, sub-seismic prodeltaic deposits observed on the shallow platform indicate that prodeltaic deposits were sourced directly from the delta plain. Clinoform surfaces with different geometries and scale are observed basinward of the palaeo platform-edge of underlying progradational sequences, correlative to mudstone-dominated prodeltaic core sections. Results indicate that platform-edge deltas developed at discrete sites in the basin due to normal regression, but the positions of these deltas are not directly relatable to variations in clinoform geometries. Transitions from third-order to fourth-order clinoform geometries record discrete transgressive–regressive cycles but are not necessarily good indicators of sandstone deposition. Because of prolonged periods with high accommodation, channel avulsions were frequent and only very fine-grained sandstone was deposited in heterolithic units at the delta front. Sandstones with good reservoir properties are predominantly found along basin margins.

• Ringdal, Kari; Buckley, Simon John; Lecomte, Isabelle; Anell, Ingrid Margareta & Braathen, Alvar (2016). From photorealistic outcrop models to synthetic seismic images. I Buckley, Simon John; Naumann, Nicole; Kurz, Tobias Herbert & Eide, Christian Haug (Red.), 2nd Virtual Geoscience Conference, Proceedings Volume. NORCE Research AS. ISSN 9788283610048. s. 182–182. Fulltekst i vitenarkiv
• Nyberg, Björn; Eide, Christian Haug; Buckley, Simon John & Howell, John Anthony (2016). Advances in the automated geometric extraction and analysis of geological bodies from virtual outcrops. I Buckley, Simon John; Naumann, Nicole; Kurz, Tobias Herbert & Eide, Christian Haug (Red.), 2nd Virtual Geoscience Conference, Proceedings Volume. NORCE Research AS. ISSN 9788283610048. s. 67–68. Fulltekst i vitenarkiv
• Anell, Ingrid Margareta; Lecomte, Isabelle; Braathen, Alvar & Buckley, Simon John (2016). Synthetic seismic illumination of small-scale growth faults, paralic deposits and low-angle clinoforms: A case study of the Triassic successions on Edgeøya, NW Barents Shelf. Marine and Petroleum Geology. ISSN 0264-8172. 77, s. 625–639. doi: 10.1016/j.marpetgeo.2016.07.005. Fulltekst i vitenarkiv
• Helland-Hansen, William; Sømme, Tor Oftedal; Martinsen, Ole Jakob; Lunt, Ian & Thurmond, John (2016). Deciphering earth's natural hourglasses: Perspectives on source-to-sink analysis. Journal of Sedimentary Research. ISSN 1527-1404. 86(9), s. 1008–1033. doi: 10.2110/jsr.2016.56. Fulltekst i vitenarkiv
• Lecomte, Isabelle; Lubrano-Lavadera, Paul Louis Francois; Botter, Charlotte; Anell, Ingrid Margareta; Buckley, Simon John & Eide, Christian Haug [Vis alle 9 forfattere av denne artikkelen] (2016). 2(3)D convolution modelling of complex geological targets – beyond 1D convolution. First Break. ISSN 0263-5046. 34(5), s. 99–107. Fulltekst i vitenarkiv
• Eide, Christian Haug; Schofield, Nick; Jerram, Dougal Alexander & Howell, John Anthony (2016). Basin-scale architecture of deeply emplaced sill complexes: Jameson Land, East Greenland Christian. Journal of the Geological Society. ISSN 0016-7649. 174(1), s. 23–40. doi: 10.1144/jgs2016-018. Fulltekst i vitenarkiv Vis sammendrag

  Igneous sills are common components in rifted sedimentary basins globally. Much work has focused on intrusions emplaced at relatively shallow palaeodepths (0 – 1.5 km). However, owing to constraints of seismic reflection imaging and limited field exposures, intrusions emplaced at deeper palaeodepths (>1.5 km) within sedimentary basins are not as well understood in regard to their emplacement mechanisms and host-rock interactions. Results from a world-class, seismic-scale outcrop of intruded Jurassic sedimentary rocks in East Greenland are presented here. Igneous intrusions and their host rocks have been studied in the field and utilizing a 22 km long ‘virtual outcrop’ acquired using helicopter-mounted lidar. The results suggest that the geometries of the deeply emplaced sills (c. 3 km) are dominantly controlled by host-rock lithology, sedimentology and cementation state. Sills favour mudstones and even exploit centimetre-scale mudstone-draped dune-foresets in otherwise homogeneous sandstones. Sills in poorly cemented intervals show clear ductile structures, in contrast to sills in cemented units, which show only brittle emplacement structures. The studied host rock is remarkably undeformed despite intrusion. Volumetric expansion caused by the intrusions is almost exclusively accommodated by vertical jack-up of the overburden, on a 1:1 ratio, implying that intrusions may play a significant role in uplift of a basin if emplaced at deep basinal levels.

• Wysocka, A; Welc, F & Czarniecka, Urszula (2016). Sedimentary environment of the Early Pleistocene gravels of the Edfu Formation from the Saqqara archaeological site (Egypt) – preliminary results. Quaternary studies in Poland. ISSN 1641-5558. 33(1), s. 69–78. doi: 10.1515/squa-2016-0007. Fulltekst i vitenarkiv
• Bojanowski, Maciej J.; Czarniecka, Urszula; Gąsiński, Arkadiusz; Jokubauskas, Petras; Kobylińska, Urszula & Kobyliński, Zbigniew [Vis alle 7 forfattere av denne artikkelen] (2016). Petrografia ceramiki pradziejowej i średniowiecznej z grodzisk zachodniej części ziem pruskic. Archaeologica Hereditas. ISSN 2451-0521. s. 113–146. Fulltekst i vitenarkiv
• Klausen, Tore Grane; Ryseth, Alf Eivind; Helland-Hansen, William & Gjelberg, Helge Kollsete (2016). Progradational and backstepping shoreface deposits in the Ladinian to Early Norian Snadd Formation of the Barents Sea. Sedimentology. ISSN 0037-0746. 63(4), s. 893–916. doi: 10.1111/sed.12242. Fulltekst i vitenarkiv
• Klausen, Tore Grane; Müller, Reidar; Slama, Jiri & Helland-Hansen, William (2016). Evidence for Late Triassic provenance areas and Early Jurassic sediment supply turnover in the Barents Sea Basin of northern Pangea. Lithosphere. ISSN 1941-8264. 9(1), s. 14–28. doi: 10.1130/L556.1. Fulltekst i vitenarkiv
• Gabrielsen, Roy Helge; Sokoutis, Dimitrios; Willingshofer, Ernst & Faleide, Jan Inge (2016). Fault linkage across weak layers during extension: an experimental approach with reference to the Hoop Fault Complex of the SW Barents Sea. Petroleum Geoscience. ISSN 1354-0793. 22(2), s. 123–135. doi: 10.1144/petgeo2015-029. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Anell, Ingrid Margareta; Serck, Christopher Sæbø; Zuchuat, Valentin & Braathen, Alvar (2020). Structural influence on Triassic deposition on the Northern Barents Shelf. Fulltekst i vitenarkiv
• Friestad, Espen; Eide, Christian Haug & Lecomte, Isabelle (2019). Synthetic seismic modelling of fluvial channels in the Blackhawk Formation as an analogue to the Triassic Barents Sea. Fulltekst i vitenarkiv
• Faleide, Jan Inge (2018). Barents Sea basin evolution - in time and space. Fulltekst i vitenarkiv
• Osmundsen, Per Terje (2018). Linking onshore and off shore structures and their role in basin development on the continental margin. Fulltekst i vitenarkiv
• Braathen, Alvar (2018). Brittle structures in southern Norway. Fulltekst i vitenarkiv
• Nystuen, Johan Petter (2018). How Old are the Mountains in South Norway. Fulltekst i vitenarkiv
• Gabrielsen, Roy Helge (2018). Sum up and looks into the future. Fulltekst i vitenarkiv
• Eide, Christian Haug; Lecomte, Isabelle; Schofield, Nick; Buckley, Simon John & Howell, John Anthony (2018). Seismic Interpretation of Mafic Sill-Complexes in Sedimentary Basins. Fulltekst i vitenarkiv Vis sammendrag

  Application of 3D-seismic reflection-data to igneous systems in sedimentary basins has led to a revolution in the understanding of mafic sill-complexes. However, there is considerable uncertainty on how geometries and architecture of sill-complexes within the subsurface relates to those imaged in seismic reflection-data. To provide constraints on how sill-complexes in seismic data should be interpreted, we present synthetic seismograms generated from a seismic-scale (22x0.25 km) outcrop in East Greenland constrained by abundant field-data. This study highlights how overlying igneous rocks adversely affect imaging of underlying intrusions and rocks by decreasing seismic amplitude, frequency and making steeply dipping features near-impossible to image. Furthermore, seismic modelling in this study shows that, because of the high impedance contrast between siliciclastic host-rock and dolerites, very thin (1-5 m) intrusions should in principle be imaged in reflection-seismic data at 3 km depth. However, comparison with actual seismic data with well-data shows significant amounts of un-imaged sill intrusions, and this is likely due to limited seismic resolution, overburden complexity, inadequate velocity-models, and interference between reflections from closely spaced sills and sill-splays. Significant improvements to sill imaging and interpretation could be made by better predicting occurrence and geometry of sill intrusions and including these in velocity models.

• Buckley, Simon John; Ringdal, Kari; Dolva, Benjamin; Lecomte, Isabelle; Anell, Ingrid Margareta & Braathen, Alvar (2018). A virtual field trip to seismic-scale outcrops of the Triassic, Edgeøya, Svalbard. Fulltekst i vitenarkiv Vis sammendrag

  Large-scale cliff sections on Edgeøya, an island in the eastern part of the Svalbard Archipelago, comprise mostly Triassic sedimentary successions, and are onshore outcrops of formations found on the offshore Barents Shelf. These outcrops are of high interest for studying the subsurface geology found offshore on the Barents Shelf, using seismic-scale features such as small-scale growth faults, paralic deposits and low-angle clinoforms (Anell et al., 2016). At Kvalpynten, an outcrop at the southern end of Edgeøya, these features can be observed, providing the opportunity to compare offshore seismic data with the outcrop expression using seismic modelling. Synthetic seismic modelling provides a means of aiding interpretation of seismic data by quantitatively and qualitatively assessing resolution, scale and level of detail of modelled onshore structures (Lecomte et al., 2015). This can give valuable insights into potential resolution and survey parameter issues, as well as limitations with seismic data. Developments in digital outcrop modelling techniques, such as lidar and photogrammetry, now allow the accurate and high-resolution capture of large and inaccessible outcrop sections, at scales comparable with seismic vertical resolution. This opens up new possibilities for generating georeferenced input to synthetic seismic modelling, which allows generation of highly visual end products for educational purposes. This contribution presents a virtual field trip to the Triassic outcrops at Kvalpynten. The dataset is based on virtual outcrop models collected using boat-based photogrammetry, covering over 10km of continuous cliff sections. The 3D outcrop model is combined with geological interpretations, logs, field photos and information panels, as well as regional elevation data to set the context of the trip. In addition, synthetic seismic data are fused with the virtual outcrop models to highlight the scale of the exposures compared to offshore seismic data. The combined dataset is explored in LIME, a high performance viewer designed for displaying disparate geospatial and field datasets (http://virtualoutcrop.com/lime).

• Czarniecka, Urszula; Haile, Beyene Girma & Krajewski, Krzysztof (2018). Middle Triassic siliciclastic deposits of Svalbard as a part of source to sink framework of the Arctic. Fulltekst i vitenarkiv
• Eide, Christian Haug; Klausen, Tore Grane; Katkov, Denis; Suslova, Anna & Helland-Hansen, William (2017). Linking an Early Triassic delta to antecedent topography: source-to-sink study of the southwestern Barents Sea margin. Fulltekst i vitenarkiv
• Ogata, Kei; Mulrooney, Mark; Braathen, Alvar; Maher, Harmon; Smyrak-Sikora, Aleksandra Anna & Anell, Ingrid Margareta [Vis alle 12 forfattere av denne artikkelen] (2017). Architecture, deformation style and petrophysical properties of a Late Triassic growth fault system in southern Edgeøya, East Svalbard. Fulltekst i vitenarkiv
• Maher, Harmon; Braathen, Alvar; Mulrooney, Mark; Ogata, Kei; Osmundsen, Per Terje & Senger, Kim [Vis alle 7 forfattere av denne artikkelen] (2017). Regional fracture systems & local fracture domains in Svalbard's diabase sills. Fulltekst i vitenarkiv
• Haile, Beyene Girma; Klausen, Tore Grane; Czarniecka, Urszula; Xi, Kelai; Jahren, Jens & Braathen, Alvar [Vis alle 7 forfattere av denne artikkelen] (2017). Diagenesis of Upper Triassic sandstones, Edgeøya, Svalbard. Fulltekst i vitenarkiv
• Braathen, Alvar (2017). Trias North – from ambitions to results – did we answer the key questions? Fulltekst i vitenarkiv
• Anell, Ingrid Margareta; Braathen, Alvar; Røhnert, Daniela; Ogata, Kei; Osmundsen, Per Terje & Smyrak-Sikora, Aleksandra Anna [Vis alle 10 forfattere av denne artikkelen] (2017). Findings of five field foragings. Sandbody distribution, clinoform geometries and depositional environments of Edgeøya, Svalbard. Fulltekst i vitenarkiv
• Line, Lina Hedvig; Jahren, Jens & Hellevang, Helge (2017). Diagenesis and Reservoir Quality of Anisian and Carnian channels in the southwestern Barents Sea. Fulltekst i vitenarkiv
• Czarniecka, Urszula (2017). Westerly-sourced siliciclastic deposits in the Triassic of Svalbard as a part of the source to sink framework of the Arctic. Fulltekst i vitenarkiv
• Buckley, Simon John; Ringdal, Kari; Dolva, Benjamin; Lecomte, Isabelle; Eide, Christian Haug & Anell, Ingrid Margareta [Vis alle 7 forfattere av denne artikkelen] (2017). Digital outcrop modelling results and workflows for derived synthetic seismic imaging. Fulltekst i vitenarkiv
• Mulrooney, Mark; Rismyhr, Bjarte; Yenwongfai, Honore Dzekamelive; Leutscher, Johan; Olaussen, Snorre & Braathen, Alvar (2017). Impacts of small‐scale faults on continental to coastal plain deposition: Evidence from the Realgrunnen Subgroup in the Goliat field, Southwest Barents Sea, Norway. Fulltekst i vitenarkiv
• Yenwongfai, Honore Dzekamelive; Mondol, Nazmul Haque; Lecomte, Isabelle & Faleide, Jan Inge (2017). Quantitative Seismic interpretation strategies for petrofacies discrimination within the Triassic: A Goliat Case Study. Fulltekst i vitenarkiv
• Faleide, Jan Inge (2017). Barents shelf tectonic evolution – recent advances. Fulltekst i vitenarkiv
• Smyrak-Sikora, Aleksandra Anna (2017). Sedimentary architecture of halfgrabens and grabens fill; Kvalpynten, SW Edgeøya. Fulltekst i vitenarkiv
• Eide, Christian Haug; Klausen, Tore Grane & Helland-Hansen, William (2017). An integrated view of sedimentary systems in the Triassic Barents Sea. Fulltekst i vitenarkiv
• Braathen, Alvar; Mulrooney, Mark; Haile, Beyene Girma; Appleyard, Tyler Ross; Yperen, Anna Elisabeth van & Smyrak-Sikora, Aleksandra Anna [Vis alle 12 forfattere av denne artikkelen] (2017). “Delta collapse” – Edgeøya delta system compared to the Ferron delta (Utah). Fulltekst i vitenarkiv
• Yenwongfai, Honore Dzekamelive; Mondol, Nazmul Haque; Faleide, Jan Inge & Lecomte, Isabelle (2017). Petrofacies characterization using prestack inversion and neural networks within the Snadd Formation of the Goliat Field, SW Barents Sea. Fulltekst i vitenarkiv Vis sammendrag

  The studied Goliat Field is the first oil field to be in production in the Norwegian sector of the Barents Sea despite an exploration history spanning over three decades. The reserves within Triassic Snadd Formation were not included in PDO (Plan for Development and Operations). This was due to poorer reservoir properties compared to the Realgrunnen Subgroup and the Kobbe Formation which together constitute the primary reservoir target in the Goliat Field. The field has an expected life time of 15 years. However, this life time can potentially be extended by applying quantitative seismic reservoir characterization techniques within more challenging minor reservoir intervals like the Snadd formation. Fluid discrimination by geophysical technique in uplifted Barents Sea areas has additional challenges as a result of a reduction in the seismic fluid sensitivity associated with rock stiffening (overconsolidation) due to prior deeper burial and quartz cementation. A multidisciplinary approach involving geology, rock physics, and geophysics has been used for petrofacies characterization from long offset prestack angle gathers and petrophysical well logs. A rock physics feasibility and AVA forward modelling reveal the sensitivity of the defined petrofacies classes to different elastic properties. The optimum prestack inversion method is subsequently selected based on the rock physics feasibility. The output from the inversion is used to derive the PEIL (Pseudo-Elastic Impedance), PI (Poisson Impedance), and LMR (Lambda-Mhu-Rho) attributes. These derived prestack attributes are then combined with poststack trace attributes in a neural network analysis. Neural networks utilize the non-linear relationships between the parameters to further optimize the inverted result and to predict the effective porosity, gamma ray, and resistivity log responses. Finally probability density functions (PDFs) extracted from the best well log training dataset are applied to a composite seismic attribute volume from which probability estimates of the classified petrofacies are obtained. Geological interpretations are then inferred based on the seismic geomorphological character observed from the different attributes. Probability maps obtained from this integrated approach has the potential to guide petrophysical reservoir modelling workflows and optimization of reservoir drainage strategies.

• Yenwongfai, Honore Dzekamelive; Mondol, Nazmul Haque; Lecomte, Isabelle; Faleide, Jan Inge & Leutscher, J (2017). Integrating prestack inversion, machine learning, and forward seismic modelling for petrofacies characterization: A Barents Sea case study. Fulltekst i vitenarkiv
• Olaussen, Snorre (2017). Upper Triassic to Middle Jurassic key sequence stratigraphic surfaces onshore offshore Arctic Norway; guidelines for prediction of facies development. Fulltekst i vitenarkiv
• Line, Lina Hedvig; Jahren, Jens & Hellevang, Helge (2017). Diagenesis and Reservoir quality of Anisian and Carnian channels in the southwestern Barents Sea. Fulltekst i vitenarkiv
• Helland-Hansen, William; Eide, Christian Haug; Klausen, Tore Grane & Braathen, Alvar (2017). Internasjonal forskningsgruppe studerer triaslagrekken på Svalbard og i Barentshavet med nytt blikk: Ny forståelse av et gigantisk elve- og deltasystem. Fulltekst i vitenarkiv
• Czarniecka, Urszula (2017). Provenance signature of the westerly-sourced siliciclastic deposits in the Triassic of Svalbard. Fulltekst i vitenarkiv
• Line, Lina Hedvig; Jahren, Jens & Hellevang, Helge (2017). Reservoir characterization of Triassic sandstones in the southwestern Barents Sea. Fulltekst i vitenarkiv
• Haile, Beyene Girma; Jahren, Jens & Hellevang, Helge (2017). New insights about thermally driven diagenetic changes due to the emplacement of magmatic sills into reservoir sediments at Wilhelmøya (Svalbard): Implications for reservoir quality. Fulltekst i vitenarkiv
• Eide, Christian Haug; Schofield, Nick; Jerram, Dougal Alexander & Howell, John Anthony (2017). Basin-scale architecture of deeply emplaced sill complexes. Fulltekst i vitenarkiv
• Flesland, Malin; Rotevatn, Atle; Lecomte, Isabelle & Eide, Christian Haug (2017). Understanding seismic imaging and controls on sill intrusions using lidar data from East Greenland. Fulltekst i vitenarkiv
• Smyrak-Sikora, Aleksandra Anna; Osmundsen, Per Terje; Braathen, Alvar; Ogata, Kei; Anell, Ingrid Margareta & Husteli, Berit [Vis alle 8 forfattere av denne artikkelen] (2017). Sedimentary architecture of siliciclastic, syntectonic graben and halfgraben fill in Kvalpynten, Edgeøya, Svalbard. Fulltekst i vitenarkiv Vis sammendrag

  An array of ten grabens/ half-grabens and their associated syntectonic basin fill (averaging approx. 700 m across) are exposed along a 9 km cliff section at Kvalpynten, Edgeøya, offering a unique opportunity to study the silisiclastic architecture of listric graben basin fill. The exposures at Kvalpynten provide a unique opportunity to correlate fault-controlled sedimentary architecture on the scale of meters to hundreds of meters with detailed facies relationships, and thus fault-induced differential accommodation with the depositional environments that filled it. The basins developed in the Late Triassic, during the deposition of the Early Carnian to Early Norian deltaic successions of Tchermakfjellet and De Geerdalen formations which is approximately the onshore equivalent to the offshore Snadd Formation. The lowermost part of the ca 400 m high Kvalpynten cliff section reveals a number of NW–SE striking growth faults with 50–100 m offset, which bound basins filled with shale and sandstone wedges. Up section, the growth faults tip out, and are buried by undeformed deltaic deposits. Integrated field studies including sedimentology and structural geology combined with surfaces mapping on a photogrammetric virtual outcrop model allowed incremental reconstruction of the grabens/ half-grabens evolution. Four transgressive surfaces were identified and mapped, allowing correlation of the sandstone packages between each basin. The sequence of faulting has been defined with respect to the mapped flooding surfaces. Faulting clearly occurred in several phases as evident by the syn-kinematic fault’s control on sediments of different ages, and from the occurrence of later forming faults rotating earlier formed fault blocks. In general, early faults defined a relatively symmetrical basin configuration whereas later phases of movement were localized mainly along south-dipping faults. This gave rise to a change to more asymmetric basins and to the formation of asymmetric, composite sedimentary bodies with stacked shoreface and offshore transition deposits. Locally, fault crests were eroded. Our sedimentological observations suggest that tidal processes were dominant during sandstone deposition within the grabens/half-grabens, expressed by the widespread occurrence of tidal bar and tidal flat deposits.

• Line, Lina Hedvig & Jahren, Jens (2017). Reservoir quality of Anisian and Carnian channels on the southwestern Barents Shelf. Fulltekst i vitenarkiv
• Smyrak-Sikora, Aleksandra Anna; Osmundsen, Per Terje; Braathen, Alvar; Mulrooney, Mark & Olaussen, Snorre (2016). Three-dimensional model of facies distribution within a Triassic half-graben, SW Edgeøya, Svalbard. Fulltekst i vitenarkiv
• Yenwongfai, Honore Dzekamelive; Mondol, Nazmul Haque; Faleide, Jan Inge & Lecomte, Isabelle (2016). Quantitative seismic reservoir characterization within the Realgrunnen Subgroup and the Havert Formation in the Goliat Field, SW Barents Sea. Fulltekst i vitenarkiv
• Yenwongfai, Honore Dzekamelive; Mondol, Nazmul Haque; Faleide, Jan Inge & Lecomte, Isabelle (2016). Prestack Simultaneous Inversion to Predict Lithology in the Realgrunnen Subgroup of the Goliat Field, SW Bareants Sea. Fulltekst i vitenarkiv
• Eide, Christian Haug; Schofield, Nick; Lecomte, Isabelle; Buckley, Simon John & Howell, John Anthony (2016). Seismic imaging of deeply emplaced sill complexes. Fulltekst i vitenarkiv
• Braathen, Alvar (2016). Svalbardfjell løser oljegåten i Barentshavet. [Journal]. Apollon. Fulltekst i vitenarkiv
• Klausen, Tore Grane; Helland-Hansen, William & Müller, Reidar (2016). Quantitative clinoform characterization –Triassic Barents Sea offshore Northern Norway. Fulltekst i vitenarkiv
• Eide, Christian Haug (2016). Jakta på storflaumen - Ka vil DU bli? Feltgeolog? Fulltekst i vitenarkiv
• Eide, Christian Haug (2016). Flaum på Vestlandet - Tankar om den store flaumen i 2014. Fulltekst i vitenarkiv
• Maher, Harmon; Senger, Kim; Ogata, Kei; Braathen, Alvar; Mulrooney, Mark & Smyrak-Sikora, Aleksandra Anna [Vis alle 7 forfattere av denne artikkelen] (2016). Mesozoic Regional Stress Field Evolution in Svalbard. Fulltekst i vitenarkiv
• Eide, Christian Haug (2016). Deeply emplaced igneous intrusions in sedimentary basins: examples from East Greenland. Fulltekst i vitenarkiv
• Line, Lina Hedvig & Jahren, Jens (2016). Reservoir quality of Middle – Late Triassic sandstones in the southwestern Barents Sea: How can we predict distribution of high reservoir quality at a sub-seismic scale? Fulltekst i vitenarkiv
• Line, Lina Hedvig & Jahren, Jens (2016). Reservoir characterization of Middle – Upper Triassic Kobbe and Snadd Formations in the southwestern Barents Sea. Fulltekst i vitenarkiv
• Anell, Ingrid Margareta; Lecomte, Isabelle; Braathen, Alvar & Buckley, Simon John (2016). Synthetic seismic expression of the onshore Kvalpynten case study: Growth-faults. Low-angle prograding deltaic system. Fulltekst i vitenarkiv
• Braathen, Alvar (2016). The Trias North project - status per May 2016. Fulltekst i vitenarkiv
• Eide, Christian Haug & Haflidason, Haflidi (2016). Den store flaumen i 2014 - Fjordsediment som arkiv for før-instrumentelle flaumar på Vestlandet. Fulltekst i vitenarkiv
• Eide, Christian Haug (2016). Tana - a very old river: Linking an Early Triassic delta to antecedent topography. Fulltekst i vitenarkiv
• Eide, Christian Haug (2016). Magmatiske intrusjoner på Øst-Grønland. geoforskning.no. Fulltekst i vitenarkiv
• Eide, Christian Haug; Klausen, Tore Grane; Anell, Ingrid Margareta; Suslova, Anna; Katov, Denis & Helland-Hansen, William (2016). Source-to-sink and mass-balance of the entire Triassic Barents Sea - Ideas, Plans and preliminary results. Fulltekst i vitenarkiv
• Ogata, Kei; Mulrooney, Mark; Braathen, Alvar; Maher, Harmon; Smyrak-Sikora, Aleksandra Anna & Anell, Ingrid Margareta [Vis alle 12 forfattere av denne artikkelen] (2016). Field-based characterisation and analogue modelling of the South Edgeøya growth faults systems. Fulltekst i vitenarkiv
• Paterson, Niall William & Mangerud, Gunn (2016). Heading towards a refined palynozonation for the late Middle - Late Triassic of the Barents Sea area. Fulltekst i vitenarkiv
• Haile, Beyene Girma; Hellevang, Helge & Jahren, Jens (2018). Reservoir quality of the Upper Triassic to Lower Jurassic sediments, NW Barents Shelf: understanding porosity evolution through diagenesis and sedimentology. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  This work presents a study on the interrelationship of burial diagenesis, depositional facies, the origin and distribution of diagenetic clay minerals, and diagenesis in sediment–sill sequences, as well as the thermal history evolution and their effect on reservoir quality distribution of the Upper Triassic to Lower Jurassic sequences on Svalbard. The study unequivocally demonstrates that there is systematic variability of diagenetic signatures as a function of depositional facies. Chlorite coating that inhibits porosity-occluding quartz cement is facies controlled. Sorting, grain size distribution and the clay fraction percentage exert a stronger control on the modes of occurrence of chlorite than on its abundance. This suggests that the best reservoir quality in a deltaic setting can be predicted with knowledge on the distribution of diagenetic signatures, specific depositional facies and sediment composition. Sedimentary basins containing igneous intrusions within sedimentary reservoir units represent an important degree of uncertainty in petroleum exploration. The intrusions obscure the normal burial diagenesis and thermal history of the basin. A new approach is employed in this study, coupling organic with inorganic paleotemperature proxies. The thermal history of a basin can then be accurately constrained. The method works well also in the important task of discriminating between sill-induced diagenesis and burial diagenesis. The findings of this study can be applicable for understanding and predicting reservoir quality distribution of the exploration target potential petroleum reservoir rocks in the subsurface.

• Eide, Christian Haug & Løvestad, Aasmund Olav (2018). Mudstone-rich fluvial systems as reservoirs: The Brushy Basin Member of the Morrison Formation, Eastern Utah. Universitetet i Bergen. Fulltekst i vitenarkiv Vis sammendrag

  Mudstone-rich fluvial systems are common in the sedimentary record, such as the Triassic of the Barents Sea, but have received little scientific attention compared to their sandstonerich counterparts. However, mudstone-rich fluvial systems often have large river channels which are easily imaged on seismic data, and thus make good exploration targets. The late stages of the Jurassic sedimentary succession of Utah, USA, comprise of a collection of lowgradient, mudstone-rich fluvial continental deposits known as the Brushy Basin Member of the Morrison Formation. This thesis investigates the Jurassic Brushy Basin Member as an analogue to mudstone-rich fluvial reservoirs and offers new insight into distributary fluvial systems. Fieldwork was done on a 2x2 km, v-shaped outcrop which offers a high degree of threedimensionality. Data acquisition was done through combining traditional fieldwork techniques with modern digital acquisition techniques and a virtual model of the outcrop was constructed. Through interpreting and correlating logs with the virtual-outcrop, facies associations and their spatial organization was identified and understood. A conceptual geological model was constructed which schematically captures the upwards changes in the fluvial system. A reservoir model based on the geological model was then built with the goal of flow-simulating oil production from the reservoir model. The results from studying the Brushy Basin Member implies a retrograding distributary fluvial system, with an upwards decrease in channel-belt width, thickness, amalgamation and interconnection. This interpretation has not been described in previous work. Production results from flow simulating the reservoir model shows that a mudstone-rich fluvial system highly depend on channel-to-channel connection which can be established through crevasse-splays. In exploration of new and poorly understood mudstone-rich fluvial systems, sub-seismic channels and crevasse-splays should be considered an upside in terms of connectivity and reservoir volumes.

• Eide, Christian Haug & Friestad, Espen (2018). Synthetic seismic modelling of fluvial channels in the Blackhawk Formation as an analogue to the Triassic Barents Sea. Universitetet i Bergen. Fulltekst i vitenarkiv Vis sammendrag

  Seismic modelling studies based on field analogues is a promising tool to close the gap between observations in field and interpretations of seismic data. Fluvial channel deposits can be great reservoirs for hydrocarbons, water and CO2-storage in the subsurface. However, there are considerable uncertainties on how size, geometries and architecture of such deposits are resolved in subsurface seismic. By seismic modelling outcrops of fluvial channel deposits that have such variation in size, geometry and architecture, the resulting synthetic seismic data can be analysed and used to better understand subsurface fluvial reservoirs. To increase knowledge about seismic imaging of fluvial deposits, I will present different synthetic seismograms from non-marine deposits in the Blackhawk Formation from a seismic-scale (250 m x 5.3 km) outcrop in Book Cliffs (Utah, USA). The study highlights what impact the dominant frequency has on the detail-level for such deposits in seismic data. In comparison with actual seismic data from the Triassic Barents Sea, synthetic seismic data with equivalent frequency show several similarities in detail. Furthermore, the process of analogue seismic modelling is evaluated, where the input from a high-detailed (down to 14 cm) outcrop-mapping shows a difference of up to 36 % in seismic amplitude compared to more conventional and simplified input-modelling. A survey in seismic interpretation of fluvial deposits was conducted using the generated seismograms, where nine participants that are geologists with different levels of experience, were asked to map out fluvial deposits at different resolutions. This gives an objective view of how the different synthetic seismograms would be interpreted by unbiased interpreters, where the results show that high-resolution seismic are interpreted in more detail but still have large uncertainties. By improving the understanding of fluvial deposits at different resolution-levels, it is possible to make seismic interpretations that are closer to the real stratigraphy.

• Solvang, Ole-Marius; Eide, Christian Haug; Helland-Hansen, William; Mangerud, Gunn & Olaussen, Snorre (2017). Sedimentological and petrographical investigations of the Early Triassic Vardebukta Formation on western Spitsbergen. Universitetet i Bergen. Fulltekst i vitenarkiv Vis sammendrag

  The earliest Triassic Barents Sea Basin received sediments from three sedimentary systems. Of these, the Fennoscandian and the Uralian systems have been well studied highlighting their sedimentology, provenance, extent and reservoir parameters. Contrarily, the system originating from Greenland/Arctic Canada has received little attention and remains poorly constrained. This study has investigated the latter system by detailed sedimentological outcrop analysis of the Induan Vardebukta Formation on western Spitsbergen at Festningen, Selmaneset and Studentdalen. The composition and texture of collected sandstone samples have been investigated by thin section analysis, warranting a comparison to its synchronous deposits in the Barents Sea. Based on the sedimentological analysis, 6 facies associations are recognized; supratidal flats, tidal sandflats, tidally influenced channels, delta front deposits, offshore transition zone and prodelta deposits. These are interpreted to have been deposited in a mixed type delta as evidenced by the great variety of sedimentary processes, and the clear progradational signature. Furthermore, the depositional environment was characterized by extensive biogenic carbonate production with a storm and wave agitated shelf. Point counting of the sandstones reveals high mineralogical maturity whereas the textural observations do not, suggesting a short transport from a nearby sedimentary source area. Additionally, the sediments show evidence of deep burial prior to deposition expressed through the sutured grain shape and the relative abundance of quartzite grains. Also, a clear bimodal grain size distribution is found in one of the samples, implying that the Vardebukta Formation partially originates from two distinctive source areas. It is possible that the sudden influx of sediments in the Induan is linked to Late Paleozoic – Early Mesozoic tectonism, which at the time led to a general tectonic uplift of the uplands to the Barents Sea Basin. This was possibly due to the onset of rifting along the western Norway - eastern Greenland margin, creating large denudation areas of previously deeply buried sediments originally sourced from Greenland/Arctic Canada.

• Flesland, Malin; Eide, Christian Haug & Lecomte, Isabelle (2017). Controls on architecture and seismic imaging of igneous intrusions: Examples from LIDAR outcrop data on Traill Ø (East Greenland) and seismic data from the conjugate Møre Margin. Universitetet i Bergen. Fulltekst i vitenarkiv Vis sammendrag

  Intrusion of sills into sedimentary successions is a fundamental and widespread process in basins at volcanic rifted margins. Although intrusions emplaced at shallow paleodepths (<1.5 km) are relatively well understood, intrusions emplaced at deeper basinal levels (<1.5 km) are much less understood due to lack of large-scale outcrops and limitation in seismic illumination and resolution. This study makes an attempt to improve the understanding of emplacement mechanisms of deeply emplaced intrusions and how these are controlled by host rock structure and stratigraphy, by using a 25 km long digital outcrop LIDAR model from exceptionally well-exposed outcrops at Traill Ø, East Greenland. This is a world-class outcrop, exposing thick sill intrusions (up to 200 m) emplaced in a complex host rock with faults and variable stratigraphy. Traill Ø shares much of its history with the conjugate Møre Margin on the Norwegian continental shelf, and therefore provides an excellent analogue for understanding igneous sills seen in seismic data from the Møre Basin. Synthetic seismic is compared to seismic data from the Møre Margin to fill the gap between field observations and seismic data. Results show that the emplacement of deeply emplaced sill intrusions (c. 3-4 km) is controlled by host rock lithology, pre-existing structures and the strength of the host rock. Sills show brittle emplacement structures with little deformation around the sill margins despite the intrusions of large amount of sills into the host rock. Sill intrusions seems to prefer extensive mudstone units, thinly interbedded mudstone and sandstone and carbonate/evaporite units. Comparison between outcrop data, synthetic seismic and seismic data can improve the understanding of deeply emplaced sill complexes in the subsurface. Thin sills and steeply dipping intrusions are commonly not imaged in seismic, leading to underestimation of the volume of sills in basins. This study demonstrates the importance of host rock lithology, pre-existing structures and basin history, in order to predict emplacement mechanisms and expression in seismic data of deeply emplaced sill intrusions. Furthermore, it contributes to the understanding of deep sill complexes in sedimentary basins on volcanic margins worldwide.

• Støen, Simen Jenvin; Mørk, Atle & Olaussen, Snorre (2016). Late Triassic sedimentology and diagenesis of Barentsøya, Wilhelmøya and eastern Spitsbergen. Norges teknisk-naturvitenskapelige universitet. Fulltekst i vitenarkiv Vis sammendrag

  This study documents and discusses the sedimentology and diagenesis of the Triassic De Geerdalen Formation on eastern Svalbard. In addition to sandstone sampling, nine sedimentary sections have been measured. These include the mountains of; Klement evfjellet, Friedrichfjellet and Smidtberget in Agardhbukta, Teistberget and Hellwaldfjellet on eastern Spitsbergen, Krefftberget, Svartnosa and Mistakodden on Barentsøya and Tumlingodden on Wilhelmøya. Based on field observations 15 facies have been defined. In turn, these have been grouped into eight facies associations that reflect environments on the marine offshore to lower shoreface (FA 1), delta front (FA 2) and delta plain (FA 3). The interpretations presented herein, is based on previous reseach in adjacent areas and cooperation with other master students. Thin section analysis and SEM investigations have been applied in order to complement sedimentological analysis, with data on sediment texture and composition, and to document factors affecting porosity in the sandstones. The De Geerdalen Formation represents a major shallowing upward sequence, and the establishment of a paralic delta plain environment is documented in the upper part of measured sections. Recurring upwards coarsening and shallowing parasequences reflects a dynamic delta nature. Delta front facies on Barentsøya and Teistberget show a fluvial dominance upon deposition, in a proximal setting (relative to a westwards prograding distributary system) compared to visited outcrops on Spitsbergen. Towards the southern (Agardhbukta) and northern exposures (Hellwaldfjellet and Wilhelmøya) thinning of delta front sandstones (FA 2) and increased influence of basinal processes upon sedimentation is documented. Distribution of porosity in the studied deltaic sandstones is largely controlled by diagenetic processes. Locally, early calcite cement has inhibited mechanical compaction, allowing an open sandstone fabric and intergranular porosity where cementation shows a patchy distribution. However, calcite cement is commonly extensive and the majority of porosity occurs as poorly connected molds. Other authigenic minerals include siderite, kaolinite, illite, chlorite, albite and quartz, with precipitation often associated with dissolution of unstable lithic fragments. Mechanisms affecting porosity are closely related to the immature composition of the De Geerdalen Formation sandstones.

• Johansen, Sondre Krogh; Mørk, Atle & Olaussen, Snorre (2016). Sedimentology and facies distribution of the Upper Triassic De Geerdalen Formation in the Storfjorden area and Wilhelmøya, eastern Svalbard. Norges teknisk-naturvitenskapelige universitet. Fulltekst i vitenarkiv Vis sammendrag

  This study investigates sediments of the Upper Triassic De Geerdalen Formation, as it is exposed on eastern Svalbard. The De Geerdalen Formation was deposited during the Early Carnian to Early Norian, on the distal area of a shallow embayment on the northern margin of Pangea. It includes a wide range of depositional environments, ranging from offshore shallow marine, paralic delta front and shoreface to coastal plain environments. The aim of the study is to document and interpret the sedimentology of the formation and the spatial and temporal evolution of depositional environments, through detailed facies analysis. Fifteen facies and eight facies associations have been defined based on observations and outcrop data. These data were collected during a one-month field season in 2015 on eastern Spitsbergen, western Barentsøya and on Wilhelmøya. The interpretation presented here is based on previous research in neighbouring areas, as well as cooperation with other master students. From the measured sections, a strong fluvial dominance is observed on the northern part of Barentsøya and interpreted to reflect a proximal position to an eastern source compared to exposures further west and north. Waves and tides become increasingly dominant towards the west, particularly in the outcrops in the Agardhbukta area and represent more distal and transitional environments compared to the succession in the eastern exposures. The succession on eastern Spitsbergen and Wilhelmøya is mostly dominated by tidal and wave processes and reflect more distal depositional environments compared to the southern and eastern part of the study area. The De Geerdalen Formation shows a typical development of multiple coarsening upwards sequences that constitute parasequences normally associated with regressive depositional systems.

• Harstad, Trond Svånå; Mørk, Atle & Olaussen, Snorre (2016). Sandstone Provenance of the De Geerdalen Formation, Svalbard - Emphasis on Petrography and Chromium Spinel Compositions. Norges teknisk-naturvitenskapelige universitet. Fulltekst i vitenarkiv Vis sammendrag

  Detrital chromium spinel mineral-chemical analyses, in combination with sandstone petrography, were conducted on samples from the Upper Triassic De Geerdalen Formation from several locations on Svalbard, in order to interpret sandstone provenance. Petrographic identification of detrital minerals and lithic fragments was used to identify source rock lithology. The accessory mineral chromium spinel was used as a petrogenetic marker to distinguish tectonic setting of mafic and ultra- mafic source rocks to the De Geerdalen Formation. All detrital chromium spinels have a Fe3+ content above 25% and an Al content below 30%, when comparing the trivalent cations Cr, Fe3+ and Al. Comparing the divalent cations Mg and Fe2+, the Mg content is between 38 and 94%. Apatite, chromium spinel, garnet, rutile, tourmaline and zircon heavy minerals are observed in sandstones along with various lithic fragments of volcanic and metapelitic origin. A considerable polycrystalline quartz content represents deformed quartzite grains, chert and spiculites. Comparing the observed chromium spinel compositional range to that in the literature indicates a compositional match with mafic to ultra- mafic continental intrusions, covering flood basalts, sub- volcanic intrusions and layered intrusions. The observed volcanic lithic fragments in the De Geerdalen Formation may have a similar origin as the detrital chromium spinels. On the other hand, the lithic clasts and heavy minerals indicate varying source rock lithologies of metasedimentary, sedimentary, volcanic and felsitic intrusive origin. The closest known possible source to chromium spinel of continental intrusion composition, and likely source to De Geerdalen Formation chromium spinel, is located on the Taimyr peninsula, representing the northernmost part of the Siberian Traps Large Igneous Province. This provenance interpretation is supported by the existence of Siberian Traps related zircon age peaks in detrital zircons of the De Geerdalen Formation. No observations suggesting varying provenance between the different Svalbard locations and samples are made.

• Haugen, Turid; Mørk, Atle & Olaussen, Snorre (2016). A Sedimentological Study of the De Geerdalen Formation with Focus on the Isfjorden Member and Palaeosols. Norges teknisk-naturvitenskapelige universitet. Fulltekst i vitenarkiv Vis sammendrag

  In this study sedimentological depositional environments of the Upper Triassic De Geerdalen Formation in Svalbard have been investigated. Facies and facies associations of the formation are presented, however the main focus has been on delta top sediments and in particular palaeosols. Special attention has been paid to the Isfjorden Member, which constitutes the uppermost part of the De Geerdalen Formation. The purpose of the study has been to identify palaeosols, and relate them to the overall depositional environments. The palaeosols have been identified by three main characteristics: roots, soil horizons and soil structure. Based on field observations an attempt to classify the palaeosols has been made. There are notable differences between brown and yellow palaeosols found in the middle and upper parts of the De Geerdalen Formation and the red and green palaeosols restricted to the Isfjorden Member. The yellow and brown palaeosols are in general immature compared to the green and red palaeosols of the Isfjorden Member. Thin sections from the Isfjorden Member on Deltaneset show excellent examples of calcrete, with clear biogenetic indicators. Distinct and alternating green and red colours might be related to fluctuations in groundwater level and reduction and oxidation of the soil profile. The palaeosols are found on floodplains, interdistributary areas and on top of proximal shoreface deposits. The number, thickness and maturity of palaeosols tend to increase upwards in the De Geerdalen Formation. The Isfjorden Member is present on Wilhelmøya, Hahnfjella, Hellwaldfjellet, Teistberget, Klement evfjellet, Friedrichfjellet, Schmidtberget and Deltaneset. The Isfjorden Member is not present at Krefftberget, Blanknuten and Muen, probably due to erosion of the upper part of the De Geerdalen Formation. The Isfjorden Member is easily recognized by coquina beds and alternating red and green mudrocks, but the lower base of the member is not clearly defined. Field-data were collected in 2014 (5th -23th of August) and 2015 (2nd of August to 6th of September). In this thesis mainly data from 2015 is presented. The localities visited are situated on Edgeøya, Barentsøya, Wilhelmøya, Agardhdalen, and west Spitsbergen. Contemporary field work was conducted in order to collect the data. In addition XRD and thin section analyses have been performed on selected samples. Collected data is compared with previous studies.

Se alle arbeider i NVA