Jan Inge Faleide

• Shephard, Grace; Abdelmalak, Mohamed Mansour; Faleide, Jan Inge; Clennett, Edward; Zahirovic, Sabin & Gac, Sebastien [Vis alle 9 forfattere av denne artikkelen] (2026). Multi-phase intra-plate rifting and deformable plate modelling of the Northeast Atlantic back to the Permian. Gondwana Research. ISSN 1342-937X. 149, s. 465–490. doi: 10.1016/j.gr.2025.09.002. Fulltekst i vitenarkiv
• Brekke, Harald; Bunkholt, Halvor Sverre Sæter; Faleide, Jan Inge & Fyhn, Michael B.W. (2025). Definition of tectono-sedimentary elements for rifted continental margins of the Norwegian and Greenland seas. Geological Society of London Memoirs. ISSN 0435-4052. 57(1), s. 97–102. doi: 10.1144/M57-2021-31. Fulltekst i vitenarkiv Vis sammendrag

  The geology of the conjugate continental margins of the Norwegian and Greenland Seas reflects 400 myr of post-Caledonian continental rifting, continental break-up between early Eocene and Miocene times, and subsequent passive-margin conditions accompanying seafloor spreading. During Devonian–Carboniferous time, rifting and continental deposition prevailed, but from the mid-Carboniferous rifting decreased and marine deposition commenced in the north, culminating in a Late Permian open seaway as rifting resumed. The seaway became partly filled by Triassic and Lower Jurassic sediments causing mixed marine–non-marine deposition. A permanent, open seaway was established by the end of the Early Jurassic and was followed by the development of an axial line of deep-marine Cretaceous basins. The final, strong rift pulse of continental break-up occurred along a line oblique to the axis of these basins. The Jan Mayen microcontinent formed by resumed rifting in a part of the East Greenland margin in Eocene–Miocene times. This complex tectonic development is reflected in the sedimentary record in the two conjugate margins, which clearly shows their common pre-break-up geological development. The strong correlation between the two present margins is the basis for defining seven tectono-sedimentary elements (TSEs) and establishing eight composite tectono-sedimentary elements (CTSEs) in the region.

• Aarseth, Iselin; Minakov, Alexander; Shulgin, Alexey; Hauge, Brede Engum; Breivik, Asbjørn & Faleide, Jan Inge [Vis alle 8 forfattere av denne artikkelen] (2025). The Storfjorden earthquake sequence: role of inherited crustal heterogeneity. Geophysical Journal International. ISSN 0956-540X. 243(3). doi: 10.1093/gji/ggaf386. Fulltekst i vitenarkiv Vis sammendrag

  A strong earthquake sequence in Storfjorden, south of Svalbard, was initiated by an Mw 6.1 event on 2008 February 21. Earthquake distribution and fault plane solutions indicate that seismic activity is controlled by unmapped NE-SW striking oblique-normal faults, contrasting with the major N-S oriented faults mapped onshore Svalbard. We present a geophysical model derived from an ocean bottom seismometer profile crossing the seismogenic zone to identify structures in the crust and uppermost mantle that potentially control the earthquake source mechanism. Traveltime forward modelling using ray tracing, combined with traveltime tomography and gravity-magnetic modelling, reveal distinct crustal domains across the earthquake region. Crystalline crustal P-wave velocities range from 6.1 to 6.7 km s−1 at the Moho depth in the eastern section. The western profile section exhibits a higher Vp velocity lower crust (6.6–7.0 km s−1) with Vp/Vs ratios of 1.75–1.8 and high density (∼3100 kg m−3). Basement depth reaches 8 km in the west, forming a sedimentary basin, and shallows eastward. The Moho remains relatively flat at 29–32 km depth throughout the profile. The N–S oriented Caledonian suture, identified from deep seismic and potential field data, traverses the Storfjorden earthquake zone. The lithological contacts within the suture zone, inferred from the new OBS data, may facilitate seismic failure oblique to the N–S oriented structure, following the regional stress field.

• Rahman, Md Jamilur; Huff, Owen Rohwer; Ahmadigoltapeh, Sajjad; Faleide, Jan Inge; Fawad, Manzar & Mondol, Nazmul Haque (2025). A Simple Method for Estimating Shale Brittleness From Seismic Data: An Example From Offshore Norway. Geophysical Prospecting. ISSN 0016-8025. 73(7). doi: 10.1111/1365-2478.70076. Fulltekst i vitenarkiv Vis sammendrag

  The brittleness of a caprock layer is an important property to measure, as it influences sealing integrity for subsurface fluid injection projects. However, brittleness is a complex function of various factors, such as mineral composition, diagenesis and effective stress, and consequently can vary spatially. Because well log‐based methods for brittleness estimation are often spatially limited, we develop a simple workflow to estimate the brittleness of a shale formation directly from seismic data. The shale in question is the Draupne Formation of the Upper Jurassic age, which acts as a primary seal of Viking Group sandstones in the Horda Platform area of the northern North Sea for hydrocarbon extraction (e.g., the Troll field) and geological CO 2 storage (e.g., Smeaheia). First, well log data from 26 wells in the Horda Platform area is aggregated, focusing on the compressional sonic, bulk density and resistivity values of the Draupne Formation. This data are used to establish a linear model relating the acoustic impedance and elastic properties‐estimated brittleness index (BI) of the Draupne Formation; these two quantities display a correlation of 0.86. By combining this acoustic impedance information with a wavelet extracted from field seismic data and using average acoustic properties for the relatively homogeneous underlying sandstone reservoir, synthetic seismograms corresponding to different BI values of the Draupne Formation are generated. The amplitudes extracted from the synthetic seismograms are then used to establish a quadratic model relating seismic amplitudes at the base Draupne reflection with the BI. Applying this quadratic model on a 2D seismic line from the Stord Basin (south of the Horda Platform) results in BI values that are close to elastic‐properties‐based values at wells which intersect the seismic line and an expected trend of increasing brittleness with respect to depth. This integrated method can be used as part of a workflow to characterize top seal effectiveness, which may be useful in fluid storage prospect evaluation.

• Smyrak-Sikora, Aleksandra; Betlem, Peter; Engelschiøn, Victoria Sjøholt; Foster, William J.; Grundvåg, Sten-Andreas & Jelby, Mads Engholm [Vis alle 26 forfattere av denne artikkelen] (2025). Phanerozoic paleoenvironmental and paleoclimatic evolution in Svalbard. Climate of the Past. ISSN 1814-9324. 21(11), s. 2133–2187. doi: 10.5194/cp-21-2133-2025. Fulltekst i vitenarkiv Vis sammendrag

  Sedimentary rocks can provide information about the Earth paleoenvironment and are studied extensively to understand the causes and consequences of global climate changes in deep time. They facilitate long-time perspectives that constrain climate models and provide analogues for how Earth systems may respond to, and recover from, intervals of profound environmental change, including projected anthropogenic change. The Norwegian Svalbard archipelago offers an extensive Phanerozoic stratigraphic record that reflects the geological evolution of the northern flanks of continental assemblages that include Laurentia, Eurasia, and Pangea. Svalbard's Phanerozoic sedimentary and paleoclimatic archive is controlled largely by Svalbard's overall northward plate-tectonic motion from equatorial to high latitudes but also by regional to local formation of topography and basins in response to long-term plate reorganization, as well as the near- and far-field influence of large igneous province activity on the tectono-stratigraphic and paleoclimatic development. Various sedimentary and geochemical proxies, such as bentonite beds and carbon isotope excursions associated with the far-reaching environmental effects of the Siberian Traps, the High Arctic Large Igneous Province, and the North Atlantic Igneous Province, are present in Svalbard's near complete geological record. As such, Svalbard is unique in that these and numerous other global environmental perturbations are recorded within a relatively restricted study area, with most of the key events preserved and recorded in easily accessible drill cores and well-exposed outcrop sections. Here we review deep-time paleoenvironmental and paleoclimate research in Svalbard by summarizing 148 peer-reviewed scientific articles. The review builds on the well-established tectono-stratigraphic and lithostratigraphic framework, as well as state-of-the art environmental reconstructions, to provide insights into the Earth system during the Phanerozoic northward drift of Svalbard and the many major biotic crises in the geological past. We focus on globally significant events including (i) the expansion of Devonian vegetation, (ii) the Carboniferous–Permian response to icehouse conditions during the Late Paleozoic Ice Age (LPIA), (iii) the End-Permian Mass Extinction (EPME) and the subsequent Triassic recovery, the (iv) Carnian Pluvial Episode, (v) Jurassic–Early Cretaceous climate perturbations including the Volgian Isotopic Carbon Excursion (VOICE) and the Aptian Ocean Anoxic Event 1a (OAE1a), and (vi) the Paleocene–Eocene Thermal Maximum (PETM). We present and synthesize existing core and outcrop data that preserve biological and geochemical proxies and climate-sensitive sedimentary facies that reflect environmental change in terrestrial and marine settings. Finally, we discuss the Phanerozoic climate recorded in Svalbard and its role in providing high-latitude calibration points for several global paleoclimate events to provide a higher-latitude perspective to complement the dominance of mid- and low-latitude locations and datasets in the literature.

• Nygaard, Madeleine Skov; Planke, Sverre; Zastrozhnov, Dmitry; Midtkandal, Ivar; Huismans, Ritske Sipke & Faleide, Jan Inge [Vis alle 13 forfattere av denne artikkelen] (2025). A tectonostratigraphic interpretation of the Mimir High through seismic-borehole tie: New insights into the Paleogene evolution of the Vøring Transform Margin. SEG technical program expanded abstracts. doi: 10.1190/image2025-4307795.1. Fulltekst i vitenarkiv Vis sammendrag

  The Mimir High is a structural high along the Vøring Transform Margin (VTM), offshore Mid-Norway, having excellent coverage of high-resolution seismic 2D and 3D data and borehole data from five wells drilled during the International Ocean Discovery Program (IODP) Expedition 396. The Mimir High developed through rift tectonics and thermal uplift that resulted in a transition through different paleoenvironments from shallow marine to coastal or subaerial and finally marine again.

• Cala, Juan Camilo Meza; Faleide, Jan Inge; Minakov, Alexander; Abdelmalak, Mohamed Mansour; Shephard, Grace & Geissler, Wolfram H. [Vis alle 9 forfattere av denne artikkelen] (2025). Crustal structure of the North Svalbard margin: Continental breakup and Eurasia Basin opening. Tectonophysics. ISSN 0040-1951. 912. doi: 10.1016/j.tecto.2025.230861. Fulltekst i vitenarkiv Vis sammendrag

  Continental breakup at the North Svalbard margin and the northern Barents Sea during the Paleogene led to the opening of the oceanic Eurasia Basin. However, the mechanisms behind this rift-to-drift evolution remain unclear. Here, we present seven crustal transects (CT1–7) integrating 2D forward modelling of potential field data and constrained by structural interpretation of multichannel seismic reflection profiles. These transects extend from the continental regions of North Svalbard to the oceanic domain in southwest Eurasia Basin. The Yermak Plateau comprises two juxtaposed tectono-magmatic blocks: the Northeast Yermak Plateau, linked to pre- or early Eurekan settings, and the Southwest Yermak Plateau, formed by shearing and oblique extension along the West Svalbard margin. Broadly, the North Svalbard margin is divided into three segments: (1) Northwest Spitsbergen-Southwest Yermak Plateau, (2) Northeast Spitsbergen-Northwest Kvitøya, and (3) Northeast Kvitøya-North Barents. Segmentation follows inherited north-northwest trending weak zones, guiding Paleogene multi-phase oblique rifting and formation of the Sophia Basin, underlain by thinned, high-density metamorphic crust. The results indicate a rift-shear breakup mode with exhumation of continental lower crust and/or serpentinized subcontinental mantle blocks within the continent-ocean transition (COT) that precedes seafloor spreading which started at ca. 53 Ma during magnetic chron C24. The continental breakup processes that led to margin segmentation reflect the interplay between inherited basement fabrics and plate opening directions of the Eurasia Basin region.

• Bauck, Marit Stokke; Faleide, Jan Inge; Fossen, Haakon & Gawthorpe, Rob (2025). Paleolandscapes recorded by the Top Basement surface in the Norwegian North Sea. Marine and Petroleum Geology. ISSN 0264-8172. 181. doi: 10.1016/j.marpetgeo.2025.107527. Fulltekst i vitenarkiv Vis sammendrag

  Mapping the diachronous Top Basement in the North Sea reveals a complex amalgamation of paleolandscapes and provides valuable insights into the Late Paleozoic and Mesozoic geologic history. To illuminate the temporal geologic and geomorphic evolution, we document and analyze geomorphic characteristics and relate these to the regional tectonostratigraphic events. The paleolandscapes represented by the Top Basement surface generally fall into the following categories: rough, irregular terrains; rough, confined drainage networks; and smooth, planar landscapes. Notably, the irregular landscape found at the base of the deep basins is covered by Upper Paleozoic sediments and represents a potential late stage of the Devonian denudation of the Caledonian mountain chain. A distinct drainage network on the Top Basement of the Patch Bank Ridge represents two exposure phases: one related to extension during Devonian exhumation and the other associated with Carboniferous exhumation. Two regional tectonic events are candidates for such Carboniferous exhumation, one is Variscan contraction, the other is the Pennsylvanian event dated onshore Greenland and Fenoscandia. Preserved drainage networks observed on various basement highs correspond to local Late Permian to Early Triassic fault block uplift. In tilted fault blocks, these features are significant, while in horst block structures, smooth, planar landscape expression occurs. This is linked to repeated uplift of horst block structures, while tilted fault blocks get buried sooner. A distinct terrain observed in a confined area on the western Måløy Slope exhibits geomorphic characteristics comparable to those found on the tilted Vette and Tusse fault blocks overlain by sediment of Triassic or older origin. Thus, we suggest that this is a strong indication that Late Permian to Early Triassic rifting impacted the Måløy Slope. Tectonic and climatic processes controlled the relief and spatial extent of these landscapes. Our findings correlate with onshore exhumation and landscape development documented from other studies onshore East Greenland and Fennoscandia. These insights highlight the potential for identifying further paleolandscape features across the wider North Sea region and beyond.

• Huff, Owen Rohwer; Evensen, Andreas Kjelsrud; Lie, Jan Erik; Bugge, Aina Juell; Sablon, Ronan & Thorkildsen, Vemund Stenbekk [Vis alle 7 forfattere av denne artikkelen] (2025). Automatic conditioning of marine seismic angle stack data with a convolutional neural network. Interpretation. ISSN 2324-8858. 13(1), s. T177–T202. doi: 10.1190/INT-2024-0034.1. Fulltekst i vitenarkiv Vis sammendrag

  Misalignment of reflections is a common problem in migrated prestack seismic data, which occurs due to moveout correction with incomplete knowledge of the velocity model. This issue persists in partial angle stack data often used for amplitude-variation-with offset (AVO) analyses and is traditionally treated with residual moveout (RMO) and trim static corrections. However, these methods require time-consuming velocity selection and parameter tuning and commonly lead to spurious alignment of reflections with noise. Therefore, we train a convolutional neural network (CNN) on synthetic examples to automatically perform conditioning and alignment of angle stack data. First, 2D synthetic common-depth point gathers are created using a convolutional modeling method and then made into input-target pairs, where the inputs are poorly moveout corrected (using inaccurate normal-moveout velocities) and the targets are accurately moveout corrected. These input-target examples are split into angle stacks for the near, mid, and far offsets and then used to train a CNN to transform the misaligned angle stacks into their more-aligned counterparts. In testing, the trained network increases the alignment of unseen synthetic data, improving the correlation with the target far-offset trace from 0.76 to 0.85 on average. The network is applied on two field examples from offshore Norway with class 3 and class 2P AVO responses, respectively. In both cases, the angle stack data predicted by the network indicate improved alignment, greater resolution in the far-offset stacked section, and increased correspondence to a well-tie synthetic seismogram, all while retaining the AVO responses. The CNN predictions are compared with angle stack data after traditional conditioning (RMO and trim static corrections), with the results being of similar or greater quality. This method enables high-quality conditioning of angle stack data at a fraction of the time required for conventional methods and is easily adaptable to different data sets.

• Abdelmalak, Mohamed Mansour; Rossetti, Lucas M.; Millett, John M.; Planke, Sverre; Jerram, Dougal Alexander & Faleide, Jan Inge [Vis alle 7 forfattere av denne artikkelen] (2025). Breakup Magmatism in the South Atlantic: Mechanisms and Implications. Earth-Science Reviews. ISSN 0012-8252. 264. doi: 10.1016/j.earscirev.2025.105088. Fulltekst i vitenarkiv Vis sammendrag

  The Early Cretaceous opening of the South Atlantic Ocean was accompanied by extensive intrusive and extrusive magmatism collectively grouped in the South Atlantic Igneous Province (SAIP). The SAIP includes the onshore Paraná-Etendeka large igneous province (PELIP), offshore seaward-dipping reflectors sequences, the Rio Grande Rise and Walvis Ridge, and voluminous intrusive magmatism. Nonetheless, the nature of the processes that lead to continental breakup remain controversial, and the environmental impact of these events is not yet fully understood. In order to investigate the tectonomagmatic evolution of the South Atlantic, we present a new compilation of the various geochemical compositions and radiometric ages associated with the SAIP as well as an estimation of magma volumes constrained by extensive seismic, gravity, and magnetic datasets. The SAIP was formed during the Early Cretaceous, from the Valanginian to Albian (135–110 Ma), with the majority of the magmatic activity lasting c. 3.5 Myr interval between 135.5 and 132 Ma. Onshore magmatism is characterized by massive outpourings of tholeiitic basaltic flows formed by melting of hotter than normal mantle along with significant lithospheric thinning. Magma source compositions varied during magmatism with enriched “plume-like” components transitioning to more depleted “MORB-like” (Mid-Ocean-Ridge-Basalt) signatures. The total magma volume of the SAIP ranges between 10 × 106 km3 and 16 × 106 km3 with a striking asymmetry in volumes of the onshore and offshore volcanism along the conjugate margins. Offshore, ∼67 to 70 % of the total magma volume is located on the African side whereas 30 to 33 % of the total magma volume is located on the South American side. Onshore, ∼10 % of the total magma volume is located on the African side whereas 90 % of the total magma volume is located on the South American side. This asymmetry in volume distribution is attributed to different factors including variations in rifting mode, differences in initial lithospheric thickness, and structural inheritance. The geochemical data were analyzed and integrated to provide insights on magma generation and source compositions along with an updated geological model for the South Atlantic magmatism. The onset of the activity of the SAIP at the start of the Weissert Event suggests that the SAIP may have played a major role on the climatic and oceanographic changes during the mid-Valanginian.

• Faleide, Jan Inge; Zastrozhnov, Dmitrii; Abdelmalak, Mohamed Mansour; Manton, Ben M.; Planke, Sverre & Gernigon, Laurent [Vis alle 8 forfattere av denne artikkelen] (2025). Møre–Vøring Composite Tectono-Sedimentary Element, Norwegian Rifted Margin, Norwegian Sea. Geological Society of London Memoirs. ISSN 0435-4052. 57, s. 174–196. doi: 10.1144/M57-2023-14. Fulltekst i vitenarkiv Vis sammendrag

  The Møre and Vøring basins at the mid-Norwegian margin were affected by a series of rift phases separated by periods of tectonic quiescence from Caledonian collapse in the Devonian to final continental break-up in the earliest Eocene. The tectonic phases were mostly extensional in nature, and the pre-drift extension across the Møre and Vøring basins since mid-Permian time has been estimated to be of the order of 200–250 km. The pre-Cretaceous basin configuration is poorly constrained due to limited seismic resolution at great depths and a lack of borehole control. A fundamental change occurred in the crustal deformation regime: from Late Jurassic distributed stretching of the upper crust to Early Cretaceous thinning at lower-crustal levels located along the axis of the Møre and Vøring basins. A westward migration of Late Cretaceous–Paleocene depocentres in the Vøring Basin reflects the focus of deformation towards the time and line of break-up. The basin architecture and evolution are summarized in relation to tectono-sedimentary elements corresponding to the main tectonic and depositional phases, and represent characteristic megasequences in the seismic data. Finally, the exploration history and main petroleum systems of the Møre and Vøring basins are presented.

• Abdelmalak, Mohamed Mansour; Minakov, Alexander; Cala, Juan Camilo Meza; Faleide, Jan Inge; Gaina, Carmen & Drachev, Sergey (2024). Eurasian Arctic Rifted Margin Composite Tectono-Sedimentary Element. Geological Society of London Memoirs. ISSN 0435-4052. 57(1). doi: 10.1144/M57-2023-24. Fulltekst i vitenarkiv Vis sammendrag

  The Eurasian Arctic Rifted Margin (EARM) spans a poorly studied transition region between the Eurasian continental shelf and the deep-water Nansen Basin. It is a conjugate margin to the Lomonosov Ridge, as both domains were united before the opening of the oceanic Eurasia Basin. The EARM is considered as a Composite Tectono-Sedimentary Element (CTSE) consisting of two individual tectono-sedimentary elements (TSEs): (1) an undefined group of poorly known pre-rift Mesozoic and Paleozoic sedimentary successions; and (2) Late Cretaceous–Paleocene synrift strata. The latter are bounded by a c. 56 Ma break-up unconformity and are overlain by the Eurasia Basin prograded margin TSE, which is not included in EARM. In the absence of drilled wells, we utilize multichannel seismic reflection (MCS) data for seismic stratigraphic correlations with nearby, better-explored, areas. The EARM CTSE is subdivided into three along-strike segments (from west to east): Svalbard–Barents Sea, the North Kara Sea and the Taimyr–Laptev Sea. Across-strike, the EARM CTSE is composed of a proximal zone of stretched crust characterized by normal faulting and a relatively narrow distal transition zone that may contain unroofed serpentinized mantle. The lack of drilled wells makes it challenging to evaluate the petroleum potential of the CTSE, although some indications of a working petroleum system presence exist.

• Abdelmalak, Mohamed Mansour; Minakov, Alexander; Faleide, Jan Inge & Drachev, Sergey (2024). Lomonosov Ridge Composite Tectono-Sedimentary Element, Arctic Ocean. Geological Society of London Memoirs. ISSN 0435-4052. 57(1). doi: 10.1144/M57-2022-72. Fulltekst i vitenarkiv Vis sammendrag

  The Lomonosov Ridge (LR) is a sliver of continental crust, a microcontinent that stretches across the Arctic Ocean and separates the Mesozoic Amerasia Basin from the Cenozoic Eurasia Basin. The LR is thought to have been separated from the northern Barents Sea–Kara Sea passive continental margin by continental rifting at about 56–53 Ma and the subsequent formation of the oceanic crust in the Eurasia Basin. Following the nomenclature of this volume, the sedimentary succession of the LR and nearby area forms a composite tectono-sedimentary element containing an assemblage of the following main tectono-sedimentary elements (TSEs): (1) an undefined group of pre-rift TSEs mostly composed of Mesozoic and poorly known Paleozoic successions; (2) the Cretaceous–Paleocene synrift TSE; and (3) the Eocene–Holocene post-rift TSE. The age of the LR's folded and metamorphosed basement can be inferred based on correlations to basement units of the northern Eurasian passive continental margin, which may include a variety of geological structures formed during Timanian, Caledonian, late Paleozoic and Mesozoic orogenic events. The pre-rift TSE includes the oldest and most poorly known offshore sedimentary succession in the Arctic region. The lithostratigraphic units of these basins were mainly characterized from a handful samples collected at the seafloor and by correlation with better known stratigraphy of the conjugate continental margin. The synrift TSE of Cretaceous–Paleocene age has been defined based on seismic data and samples of sedimentary rocks recovered during the Arctic Coring Expedition (ACEX), as well as from seismic facies correlation between the LR and the Podvodnikov–Makarov, Laptev and East Siberian Sea basins. The post-rift Cenozoic sedimentary record was documented by the ACEX well in the central part of the LR.

• Faleide, Jan Inge; Wong, Po Wan; Hassaan, Muhammad; Gabrielsen, Roy Helge; Abdelmalak, Mohamed Mansour & Planke, Sverre [Vis alle 9 forfattere av denne artikkelen] (2024). West Barents Sheared Margin Composite Tectono-Sedimentary Element, Norwegian Greenland Sea and Fram Strait. Geological Society of London Memoirs. ISSN 0435-4052. 57(1). doi: 10.1144/M57-2023-19. Fulltekst i vitenarkiv Vis sammendrag

  The West Barents Sheared Margin developed in response to break-up and initial opening of the NE Atlantic and links to the Arctic Eurasia Basin. It consists of three first-order segments: (1) a southern sheared margin segment bounding the deep SW Barents Sea basins; (2) a central rifted margin segment west of Bjørnøya; and (3) a northern initially sheared margin segment that was later exposed to oblique extension west of Svalbard. The geometry of the margin included releasing, as well as restraining, bends that inflicted substantial impact on the deformation along the sheared margin. In light of structural, stratigraphic and sedimentological investigations in recent years, the first-order three-fold subdivision of the Barents shear margin has been strengthened and expanded on. It has become even clearer that this subdivision reflects the margin geometry and the shifting far-field and local stress configurations. Prior to the final stages of rifting and break-up of the NE Atlantic in the Paleogene, the study area was part of a broad and extensive basin province comprising deep sedimentary basins. The line of break-up cut diagonally across the regional basin province so that different parts of it are now located in the mid-Norwegian margin, in the NE Greenland margin and in the SW Barents Sea. These areas share a long and complex history of multiple rift phases throughout Late Paleozoic and Mesozoic times, and information from these areas is integrated into the description of the West Barents Sheared Margin Composite Tectono-Sedimentary Element. The marginal basins in the SW Barents Sea are the least explored area on the Norwegian continental shelf and sporadic exploration activity has had limited success. A petroleum potential still exist that will be elaborated in renewed upcoming activity.

• Cala, Juan Camilo Meza; Minakov, Alexander; Faleide, Jan Inge; Abdelmalak, Mohamed Mansour; Shephard, Grace & Mattingsdal, Rune [Vis alle 8 forfattere av denne artikkelen] (2024). Late Cenozoic intraplate volcanism as a trigger for hydrothermal venting in the Arctic southwestern Eurasia Basin. Communications Earth & Environment. 5. doi: 10.1038/s43247-024-01843-4. Fulltekst i vitenarkiv Vis sammendrag

  Intraplate volcanism has occurred for the last 35 million years within Northeast Atlantic and Arctic margins, including the western Barents Sea, Svalbard, and northern Greenland. Earlier studies have suggested that some of this volcanism might be sourced from nearby mid-ocean ridges. However, legacy data does not reveal correlations between the sporadic volcanism, despite comparable setting, ages, and compositions of basalts across the area. Here, we utilize a compilation of geophysical data to document late Cenozoic intraplate volcanism affecting the northeastern Yermak Plateau and southwestern Eurasia Basin located north of Svalbard. The identified seabed and subsurface features include volcanic (Mound-A) and hydrothermal vent systems (Tayrona Vent) formed approximately 10 and 2.6 million years ago, respectively. These intraplate volcanic products are coincident in age and origin with observed hydrothermal systems on Svalbard and Northeast Atlantic. We propose that these magmatic features are the result of intraplate volcanism associated with seismic and thermal anomalies in the mantle beneath northern Svalbard.

• Bauck, Marit Stokke; Faleide, Jan Inge; Fossen, Haakon; Hassaan, Muhammad & Braathen, Alvar (2024). Late Palaeozoic structural evolution of the Patch Bank Ridge and Utsira High, northern North Sea. Basin Research. ISSN 0950-091X. 36(5). doi: 10.1111/bre.12890. Fulltekst i vitenarkiv Vis sammendrag

  This study focuses on the Late Palaeozoic development of the area east of Utsira High in the North Sea, where the stratigraphic section below the late Permian Rotliegend Group is undrilled. We use regional 3D seismic data to study structuring, sediment distribution and geomorphology across the Patch Bank Ridge and Utsira High in the North Sea. The results show that the Stord Basin and the bounding Utsira East fault initially developed during the Late Palaeozoic extension, probably during the Devonian, and that the Utsira Shear Zone controlled the location of Late Palaeozoic depocentres. The Patch Bank Ridge is an uplifted part of the Stord Basin where we identify Late Palaeozoic growth strata along the southern and northern flanks, indicating a similar timing of the structural evolution in this area. Two key wells, in the Sele High and Ling Depression, are used to relate a Late Palaeozoic isopach map with regional structuring, surface tilt and basement morphology to the enigmatic parts of the Late Palaeozoic basin system. Our results supplement regional models for the Late Palaeozoic basin development, we suggest that the deeply eroded Devonian half-grabens preserved on the Utsira High formed parts of an extensive basin system that show stratigraphic expansion towards their bounding faults. The Top Basement surface at these highs offers several distinct geomorphologies that evolved during three periods of exposure, expressed as (i) a tilted and rugose landscape, (ii) distinct drainage networks and (iii) peneplain surfaces. Cover sediments place these landscapes to the (i) Devonian, (ii) Carboniferous/Permian/Triassic and (iii) Late Triassic periods.

• Abdelmalak, Mohamed Mansour; Polteau, Stephane; Planke, Sverre; Faleide, Jan Inge; Lebedeva-Ivanova, Nina N. & Myklebust, Reidun (2024). NE Canada Rifted Margin Composite Tectono-Sedimentary Element, Baffin Bay, Davis Strait and Labrador Sea. Geological Society of London Memoirs. ISSN 0435-4052. 57(1). doi: 10.1144/M57-2021-44. Fulltekst i vitenarkiv
• Faleide, Jan Inge; Abdelmalak, Mohamed Mansour; Zastrozhnov, Dmitrii; Lasabuda, Amando P. E.; Hjelstuen, Berit Oline Blihovde & Laberg, Jan Sverre [Vis alle 7 forfattere av denne artikkelen] (2024). Norwegian Sea Oceanic Basin and Prograded Margins Composite Tectono-Sedimentary Element. Geological Society of London Memoirs. ISSN 0435-4052. 57(1). doi: 10.1144/M57-2023-26. Fulltekst i vitenarkiv Vis sammendrag

  The Norwegian Sea oceanic basins and prograded margins have developed since NE Atlantic break-up in the earliest Eocene. Significant amounts of sediments were fed to the regionally subsiding and widening Norwegian Sea during the Cenozoic as a result of several phases of uplift and erosion of the bounding shelves and their hinterland. Despite an overall passive-margin evolution, the area experienced tectonic events and associated processes that interrupted the regional subsidence, causing contraction/inversion and tilting. The post-break-up depositional history of the mid-Norwegian margin comprises two main stages: (1) middle Eocene–Pliocene margin subsidence and relatively modest sedimentation during a period of climatic decline; and (2) latest Pliocene–Pleistocene full-scale northern hemisphere glaciations that resulted in deep erosion of shelves and hinterlands, and very high sedimentation rates and large-scale continental margin progradation. Slope failures within rapidly deposited glacial sediments affect

• Huff, Owen Rohwer; Thorkildsen, Vemund Stenbekk; Greiner, Thomas Andre Larsen; Lie, Jan Erik; Evensen, Andreas & Bugge, Aina Juell [Vis alle 7 forfattere av denne artikkelen] (2024). Near offset reconstruction for marine seismic data using a convolutional neural network. Geophysical Prospecting. ISSN 0016-8025. 72(6), s. 2164–2185. doi: 10.1111/1365-2478.13505. Fulltekst i vitenarkiv Vis sammendrag

  Marine seismic data is often missing near offset information due to separation between the source and receiver cables. To solve this problem, a convolutional neural network is trained on synthetic seismic data to reconstruct the near offset gap. The synthetic data is created using a two-dimensional finite difference method within a heterogeneous velocity model. These synthetics are generated with a source-over-receiver acquisition geometry so that they contain complete near offset data. The convolutional neural network is then trained on input-target synthetic pairs where the inputs are common midpoint gathers with the near offset section removed, and the targets are the same gathers with the near offset section retained. Following training, the robustness of the method is investigated with regards to common midpoint data sorting, normal moveout correction and changes in the velocity model. It is found that training on common midpoint-sorted data results in 2.8 times lower error than training on shot gathers, that normal moveout correction of the training data makes no significant difference in error levels, and that the model can reconstruct realistic near offsets on synthetic data generated 10 km away within the heterogeneous velocity model. In field data testing, first a dataset with source-over-cable acquisition geometry from the Barents Sea is used to compare the reconstructed wavefields to ground truth values. Although the reconstructed amplitudes require minor scaling to match the true values, predictions on this dataset yield 2.5 times lower near offset reconstruction error compared to a simple Radon transform interpolation method. Furthermore, amplitude versus offset gradient and intercept sections from the Barents Sea dataset are estimated with half the error when including the convolutional neural network-predicted near offset data, compared to only using the conventionally-acquirable portion of the data (beyond 112.5 m of offset). In a secondary field data test, a conventional northern North Sea dataset is used to demonstrate how the method may be applied in practice. Here, the convolutional neural network generates more realistic predictions than the Radon method, and the gradient and intercept sections calculated using the convolutional neural network-predicted traces have higher signal-to-noise ratios than the sections calculated using only the original data. The combination of high-quality synthetic training data and interpolation in the common midpoint domain enables near offset reconstruction at significant depth (1 s of two-way traveltime or more), which is demonstrated in both synthetic and field examples.

• Faleide, Jan Inge; Abdelmalak, Mohamed Mansour; Minakov, Alexander; Cala, Juan Camilo Meza; Lasabuda, Amando P. E. & Gaina, Carmen [Vis alle 7 forfattere av denne artikkelen] (2024). Eurasia Basin Composite Tectono-Sedimentary Element. Geological Society of London Memoirs. ISSN 0435-4052. 57(1). doi: 10.1144/m57-2023-16. Fulltekst i vitenarkiv Vis sammendrag

  The Eurasia Basin formed by continental breakup and separation of the Lomonosov Ridge from the northern Barents-Kara shelves at about 54-56 Ma. It was a restricted oceanic basin since its formation until the Miocene, when extensive water circulation between the North Atlantic and Arctic commenced through the Fram Strait gateway. The opening of the oceanic gateway had large impact on paleoceanography and paleoclimate, which evolved from an Eocene greenhouse to a Neogene icehouse associated with northern hemisphere glaciations. The Eocene to present sedimentary fill of the Eurasia Basin was mainly sourced from surrounding shelf areas in the Barents, Kara and Laptev seas, which experienced widespread Cenozoic uplift and erosion during several phases. The stratigraphy of the Eurasia Basin is poorly constrained due to lack of boreholes penetrating the basin fill. We therefore have to rely on seismic stratigraphy and tentative ages assigned to sequences and their boundaries terminating on top of oceanic basement of

• Bott, Judith; Scheck-Wenderoth, Magdalena; Kumar, Ajay; Cacace, Mauro; Noe, Sebastian & Faleide, Jan Inge (2024). Density and strength variations in the mantle lithosphere affect the distribution of intraplate earthquakes. Communications Earth & Environment. 5. doi: 10.1038/s43247-024-01417-4. Fulltekst i vitenarkiv Vis sammendrag

  The distribution of earthquakes in stable intracontinental tectonic settings is typically far more diffuse than along plate boundaries and the causative mechanisms underlying some recognizable clustering are not understood. Here we show that seismicity in intraplate western and central Europe is largely limited to regions that exhibit a low-density layer in the uppermost lithospheric mantle and preferentially clustered above lateral gradients in upper mantle effective viscosity. The basis for these new insights into the thermal and density configuration of the upper mantle is provided by a shear-wave tomographic model. We propose that the spatial correlations between mantle low-density bodies and crustal seismicity reflect the importance of buoyancy forces within the mantle lithosphere. In addition, under the interaction of forces due to mantle gravitational instabilities, plate tectonics and postglacial rebound, the variably hot and strong mantle lithosphere responds by localized deformation which imposes differential loading on the overlying crust.

• Corseri, Romain; Seillé, Hoel; Faleide, Jan Inge; Planke, Sverre; Senger, Kim & Abdelmalak, Mohamed Mansour [Vis alle 9 forfattere av denne artikkelen] (2024). Deep basin conductor characterization using machine learning-assisted magnetotelluric Bayesian inversion in the SW Barents Sea. Geophysical Journal International. ISSN 0956-540X. 238(1), s. 420–432. doi: 10.1093/gji/ggae166. Fulltekst i vitenarkiv Vis sammendrag

  In this paper, we use a new workflow to substantiate the characterization of a prominent, deep sediment conductor in the hyperextended Bjørnøya Basin (SW Barents Sea) previously identified in smooth resistivity models from 3-D deterministic inversion of magnetotelluric data. In low-dimensionality environments like layered sedimentary basin, 1-D Bayesian inversion can be advantageous for a thorough exploration of the solution space, but the violation of the 1-D assumption has to be efficiently handled. The primary geological objectives of this work is therefore preceded by a secondary task: the application of a new machine learning approach for handling the 1-D violation assumption for 21 MT field stations in the Barents Sea. We find that a decision tree can adequately learn the relationship between MT dimensionality parameters and the 1-D–3-D residual response for a training set of synthetic models, mimicking typical resistivity structures of the SW Barents Sea. The machine learning model is then used to predict the dimensionality compensation error for MT signal periods ranging of 1–3000 s for 21 receivers located over the Bjørnøya Basin and Veslemøy High. After running 1-D Bayesian inversion, we generated a posterior resistivity distribution for an ensemble of 6000 1-D models fitting the compensated MT data for each 21 field stations. The proportion of 1-D models showing ρ < 1 Ω·m is consistently beyond 80 per cent and systemically reaches a maximum of 100 per cent in the Early Aptian–Albian interval in the Bjørnøya Basin. In hyperextended basins of the SW Barents Sea, the dimensionality compensation workflow has permitted to refine the characterization of the deep basin conductor by leveraging the increased vertical resolution and optimal used of MT data. In comparison, the smooth 3-D deterministic models only poorly constrained depth and lateral extent of the basin anomaly. The highest probability of finding ρ < 1 Ω·m is robustly assigned to the syn-tectonic Early Aptian–Albian marine shales, now buried at 6–8 km depth. Based on a theoretical two phase fluid-rock model, we show that the pore fluid of these marine shales must have a higher salinity than seawater to explain the anomaly ρ < 1 Ω·m. Therefore, the primary pore fluid underwent mixing with a secondary brine during rifting. Using analogue rift systems in palaeomargins, we argue that two possible secondary brine reservoir may contribute to deep saline fluid circulation in the hyperextended basin: (1) Permian salt-derived fluid and, (2) mantle-reacted fluid from serpentinization.

• Senger, Kim; Shephard, Grace; Ammerlaan, Fenna; Anfinson, Owen; Audet, Pascal & Coakley, Bernard [Vis alle 20 forfattere av denne artikkelen] (2024). Arctic Tectonics and Volcanism: a multi-scale, multi-disciplinary educational approach. Geoscience Communication. ISSN 2569-7102. 7(4), s. 267–295. doi: 10.5194/gc-7-267-2024. Fulltekst i vitenarkiv Vis sammendrag

  Geologically, the Arctic is one of the least-explored regions of Earth. Obtaining data in the high Arctic is logistically, economically, and environmentally expensive, but the township of Longyearbyen (population of 2617 as of 2024) at 78° N represents a relatively easily accessible gateway to Arctic geology and is home to The University Centre in Svalbard (UNIS). These unique factors provide a foundation from which to teach and explore Arctic geology via the classroom, the laboratory, and the field. UNIS was founded in 1993 as the Norwegian “field university”, offering field-based courses in Arctic geology, geophysics, biology, and technology to students from Norway and abroad. In this contribution, we present one of the educational components of the international collaboration project NOR-R-AM (a Norwegian-Russian-North American collaboration in Arctic research and collaboration, titled Changes at the Top of the World through Volcanism and Plate Tectonics) which ran from 2017 to 2024. One of the key deliverables of NOR-R-AM was a new graduate (Master's and PhD-level) course called Arctic Tectonics and Volcanism that we have established and taught annually at UNIS since 2018 and detail herein. The course's main objective is to teach the complex geological evolution of the Arctic from the Devonian period (∼ 420 million years ago, Ma) to the present day through integrating multi-scale datasets and a broad range of geoscientific disciplines. We outline the course itself before presenting student perspectives based on both an anonymous questionnaire (n=27) and in-depth perceptions of four selected students. The course, with an annual intake of up to 20 MSc and PhD students, is held over a 6-week period, typically in spring or autumn. The course comprises modules on field and polar safety, Svalbard/Barents Sea geology, wider Arctic geology, plate tectonics, mantle dynamics, geo- and thermochronology, and geochemistry of igneous systems. A field component, which in some years included an overnight expedition, provides an opportunity to appreciate Arctic geology and gather field observations and data. Digital outcrop models, photospheres, and tectonic plate reconstructions provide complementary state-of-the-art data visualization tools in the classroom and facilitate efficient fieldwork through pre-fieldwork preparation and post-fieldwork quantitative analyses. The course assessment is centred around an individual research project that is presented orally and in a short and impactful Geology journal-style article. Considering the complex subject and the diversity of students' backgrounds and level of geological knowledge before the course, the student experiences during this course demonstrate that the multi-disciplinary, multi-lecturer field-and-classroom teaching is efficient and increases their motivation to explore Arctic science.

• Aleshina, Ksenia F.; Nikishin, Anatoly M.; Malyshev, Nikolay A. & Faleide, Jan Inge (2024). East Barents Megabasin: Tectonostratigraphy and main epochs of geological history. Marine Geology. ISSN 0025-3227. 469. doi: 10.1016/j.margeo.2024.107239. Fulltekst i vitenarkiv
• Pichel, Leonardo Muniz; Huismans, Ritske Sipke; Gawthorpe, Rob & Faleide, Jan Inge (2023). How post-salt sediment flux and progradation rate influence salt tectonics on rifted margins: Insights from geodynamic modelling. Basin Research. ISSN 0950-091X. 35(6), s. 2364–2380. doi: 10.1111/bre.12802. Fulltekst i vitenarkiv Vis sammendrag

  Continental rifted margins can be associated with widespread and thick salt deposits, which are often formed during the final stages of rifting, prior to breakup. These salt-bearing margins are typically characterized by pronounced post-rift salt tectonics with variable and complex structural styles and evolution. We use a lithosphere-scale geodynamic numerical model to investigate the role of varying post-rift sediment fluxes and progradation rates on rifted margin salt tectonics. We focus on a single, intermediate, rifted margin type and salt basin geometry to explore scenarios with different: (i) constant and (ii) time-varying post-salt sediment fluxes. We demonstrate that these promote significant contrasts in the style and magnitude of salt tectonics in the proximal, transitional and distal margin domains. The differences are primarily controlled by the relationship between the rates of sediment progradation (Vprog) and salt flow (Vs). When Vprog > Vs, the salt is rapidly buried and both vertical and lateral salt flow are suppressed across the entire margin. When Vprog < Vs, the salt flows vertically and seaward faster than sediments prograde producing major diapirism in the proximal domain and major distal nappe advance, but only moderate overburden extension and distal diapirism. When Vprog ~ Vs, there is moderate proximal diapirism and distal nappe advance, but major updip extension and downdip shortening, which produces major distal diapirism. Modelling results are comparable to various natural systems and help improve our understanding of the controls and dynamics of salt tectonics along salt-bearing rifted margins.

• Wong, Po Wan; Midtkandal, Ivar & Faleide, Jan Inge (2023). Origin of paired extension-compression during rotational rifting: An early Paleogene example from the northeast Atlantic region and its implications. Geology. ISSN 0091-7613. 52(1), s. 27–32. doi: 10.1130/G51730.1. Fulltekst i vitenarkiv Vis sammendrag

  Abstract The formation of paired extension-compression (PEC) postulated by rotational kinematics of rift propagation is demonstrated by analogue models but rarely observed in nature. In our study of the early Paleogene continental rift in the northeast Atlantic, a PEC is proposed based on the northeastward propagation and the coeval compression at the rift tip. The propagation is deduced from tectono-magmatic trends, including along-axis development of magmatism, and migration of tectonic faulting inward and toward the rift tip. Where this propagation terminated, we documented coeval extension and compression in the form of a horst-and-graben system (H&amp;G) and V-shaped anticline (VA), respectively. Given their structural characteristics and spatiotemporal relationships with the rift, their origin is best illustrated by a three-stage model: (1) Rifting initiated at the site of mantle upwelling and propagated northeastward in the Paleocene. (2) The rift tip was stalled by an elevated mafic-ultramafic body at the Barents Shelf, which led to forward projection of the rift’s driving force to create the H&amp;G and the VA (PEC), dissipating the along-axis force component. (3) Domination of axis-perpendicular components then promoted orthogonal extension and sheared margin development. Our study suggests that PEC has a crucial role in both termination of propagation and rift-mode conversion.

• Pichel, Leonardo Muniz; Huismans, Ritske Sipke; Gawthorpe, Robert Leslie & Faleide, Jan Inge (2023). Post-salt carbonates control salt-tectonic minibasin formation. Geology. ISSN 0091-7613. 52(1), s. 82–86. doi: 10.1130/G51717.1. Fulltekst i vitenarkiv
• Berndt, Christian; Planke, Sverre; Zarikian, Carlos A. Alvarez; Frieling, Joost; Jones, Morgan Thomas & Millett, John M. [Vis alle 36 forfattere av denne artikkelen] (2023). Shallow-water hydrothermal venting linked to the Palaeocene–Eocene Thermal Maximum. Nature Geoscience. ISSN 1752-0894. 16, s. 803–809. doi: 10.1038/s41561-023-01246-8. Fulltekst i vitenarkiv Vis sammendrag

  The Palaeocene–Eocene Thermal Maximum (PETM) was a global warming event of 5–6 °C around 56 million years ago caused by input of carbon into the ocean and atmosphere. Hydrothermal venting of greenhouse gases produced in contact aureoles surrounding magmatic intrusions in the North Atlantic Igneous Province have been proposed to play a key role in the PETM carbon-cycle perturbation, but the precise timing, magnitude and climatic impact of such venting remains uncertain. Here we present seismic data and the results of a five-borehole transect sampling the crater of a hydrothermal vent complex in the Northeast Atlantic. Stable carbon isotope stratigraphy and dinoflagellate cyst biostratigraphy reveal a negative carbon isotope excursion coincident with the appearance of the index taxon Apectodinium augustum in the vent crater, firmly tying the infill to the PETM. The shape of the crater and stratified sediments suggests large-scale explosive gas release during the initial phase of vent formation followed by rapid, but largely undisturbed, diatomite-rich infill. Moreover, we show that these vents erupted in very shallow water across the North Atlantic Igneous Province, such that volatile emissions would have entered the atmosphere almost directly without oxidation to CO2 and at the onset of the PETM.

• Cala, Juan Camilo Meza; Tsikalas, Filippos; Abdelmalak, Mohamed Mansour & Faleide, Jan Inge (2023). Structural analysis and measured extension in fault complexes along the Lofoten-Vesterålen margin, offshore Norway, in the context of crustal-scale rifting towards breakup in NE Atlantic. Basin Research. ISSN 0950-091X. 35(4), s. 1329–1361. doi: 10.1111/bre.12756. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Late Cretaceous–Palaeocene continental extension within the Lofoten‐Vesterålen margin is investigated by integrating 2D‐3D seismic and potential field datasets, together with updated crustal transects. Most of that deformation is recorded by two low‐angle detachment structures named West Røst High Fault Complex (WRHFC) and North Utrøst Ridge Fault Complex (NURFC) located at the southern and central‐northern portions of the studied area, respectively. Multiple extensional episodes of various intensities were mapped as different fault stages, including one Albian‐Cenomanian phase, four early Late Cretaceous phases, three Late Cretaceous to latest Cretaceous–Palaeocene phases, and one Palaeocene phase. The WRHFC is narrower in extent and has accommodated a relatively greater amount of localized extension (ca. 18–19 km), whereas the NURFC occupies a wider area with widespread extension intensity (ca. 6–8 km). In comparison, the total across‐margin average extension within the southern, central, and northern portions of the Lofoten‐Vesterålen and NE Greenland conjugate margins are ca. 192, 221, and 266 km, respectively. Such results indicate an apparent extension discrepancy between derived extension from measured fault‐block geometries within the fault complexes and the whole conjugate margin system, with only ca. 11% and 13% of the extension seen on the studied seismic profiles on the WRHFC and NURFC, respectively. The corrected maximum extension for purely sub‐seismic resolution faulting on both the WRHFC and NURFC fault complexes is ca. 164 and 46 km, respectively. Finally, both WRHFC and NURFC structures provide key evidence for a ductile mode of deformation towards breakup that is expressed through shear zones‐rift topography interactions with overlaying listric/detachment faults. These features reflect the resulting multiphase tectonic evolution across the asymmetric Lofoten‐Vesterålen and NE Greenland conjugate margins, and the obliquity in the breakup axis location along them. The study outcomes are pertinent and applicable to understand the breakup evolution of the northern NE Atlantic and its vicinity.

• Würtzen, Camilla Louise; Hassaan, Muhammad; Anell, Ingrid; Nystuen, Johan Petter; Faleide, Jan Inge & Midtkandal, Ivar (2023). Alluvial development during climate fluctuations depicted with spectral decomposition of the Middle Triassic to Lower Jurassic post-rift succession in the Horda Platform (Norway) and the impact on reservoir properties. Basin Research. ISSN 0950-091X. 35(6), s. 2301–2327. doi: 10.1111/bre.12799. Fulltekst i vitenarkiv Vis sammendrag

  Abstract For the first time, this study presents interpretations of alluvial fans in spectral decomposition RGB Blends, analysed in seismic time slices from the Middle Triassic to Lower Jurassic stratigraphical interval of the Horda Platform (northern North Sea). The time slices record a shifting alluvial fan front, fluvial variability, uplift and erosion and reveals depositional elements that may set the common conception of the geological development of this area during the Early–Middle Mesozoic up for discussion. Results show that the Upper Triassic Lunde Formation in the eastern margin of the Horda Platform was characterized by the deposition of coalesced alluvial fans. A variable extent of the fan front through the Upper Triassic is linked to interplaying allogenic factors: uplifted source areas in the aftermath of Early–Middle Triassic rifting determined sediment availability; climate transitioning from arid to semi‐humid, with increasingly fluctuating precipitation, controlled sedimentation, and run‐off; provenance dictated bulk sedimentology and affected prevailing alluvial processes. An overall retreat of the fan system through the Late Triassic coincided with a significant change in landscape characteristics at the transition into the overlying Statfjord Group. Uplift and initial tilting of the Horda Platform caused landscape degradation and the formation of plateaus and incised valleys, contemporaneous with increased humidity and marine transgression, forming estuaries. The shift in depositional style has implications for reservoir properties, creating complexity and heterogeneity in terms of facies distribution and connectivity, which may benefit potential CO 2 storage. Upper Triassic alluvial fan development in the Horda Platform (northern North Sea) depicted through spectral decomposition of seismic time slices Enhanced level of seismic stratigraphic interpretation with RGB blending Impact of allogenic factors on alluvial depositional development Implications of alluvial variability on reservoir properties

• Gabrielsen, Roy Helge; Gianennas, Pangiptis, A.; Sokoutis, Dimitrios; Willingshofer, Ernst; Hassaan, Muhammad & Faleide, Jan Inge (2023). Analogue experiments on releasing and restraining bends and their application to the study of the Barents Shear Margin. Solid Earth (SE). ISSN 1869-9510. 14(9), s. 961–983. doi: 10.5194/se-14-961-2023. Fulltekst i vitenarkiv Vis sammendrag

  The Barents Shear Margin separates the Svalbard and Barents Sea from the North Atlantic. During the break-up of the North Atlantic the plate tectonic configuration was characterized by sequential dextral shear, extension, and eventually contraction and inversion. This generated a complex zone of deformation that contains several structural families of overlapping and reactivated structures. A series of crustal-scale analogue experiments, utilizing a scaled and stratified sand–silicon polymer sequence, was used in the study of the structural evolution of the shear margin. The most significant observations for interpreting the structural configuration of the Barents Shear Margin are the following. 1. Prominent early-stage positive structural elements (e.g. folds, push-ups) interacted with younger (e.g. inversion) structures and contributed to a hybrid final structural pattern. 2. Several structural features that were initiated during the early (dextral shear) stage became overprinted and obliterated in the subsequent stages. 3. All master faults, pull-apart basins, and extensional shear duplexes initiated during the shear stage quickly became linked in the extension stage, generating a connected basin system along the entire shear margin at the stage of maximum extension. 4. The fold pattern was generated during the terminal stage (contraction–inversion became dominant in the basin areas) and was characterized by fold axes striking parallel to the basin margins. These folds, however, strongly affected the shallow intra-basin layers. The experiments reproduced the geometry and positions of the major basins and relations between structural elements (fault-and-fold systems) as observed along and adjacent to the Barents Shear Margin. This supports the present structural model for the shear margin.

• Lasabuda, Amando P. E.; Hanssen, Alfred; Laberg, Jan Sverre; Faleide, Jan Inge; Patton, Henry & Abdelmalak, Mohamed Mansour [Vis alle 8 forfattere av denne artikkelen] (2023). Paleobathymetric reconstructions of the SW Barents Seaway and their implications for Atlantic–Arctic ocean circulation. Communications Earth & Environment. 4. doi: 10.1038/s43247-023-00899-y. Fulltekst i vitenarkiv Vis sammendrag

  Unravelling past, large-scale ocean circulation patterns is crucial for deciphering the longterm global paleoclimate. Here we apply numerical modelling to reconstruct the detailed paleobathymetry-topography of the southwestern inlet of the Barents Seaway that presently connects the Atlantic and Arctic oceans. Subaerial topography was likely enough to block Atlantic Water from entering the Barents Seaway in the earliest Eocene (c. 55 Ma). The water may have entered in the middle Eocene (c. 47 Ma) as observed from major basin subsidence, but paleotopographic highs to the east may have hindered connections between the two oceans. From the Oligocene (c. 33 Ma) until the onset of the Quaternary (c. 2.7 Ma), basin shallowing and regional shelf uplift blocked Atlantic Water from entering the Barents Seaway. Our results imply that the Fram Strait remained the sole gateway for Atlantic Water into the Arctic Ocean since its opening in the Miocene until the Quaternary.

• Dacal, María Laura Gómez; Scheck-Wenderoth, Magdalena; Faleide, Jan Inge; Abdelmalak, Mohamed Mansour; Bott, Judith & Anikiev, Denis (2023). Tracing the Iceland plume and North East Atlantic breakup in the lithosphere. Communications Earth & Environment. 4. doi: 10.1038/s43247-023-01120-w. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Plumes are domains where hotter material rises through Earth´s mantle, heating also the moving lithospheric plates that may experience thinning or even continental breakup. In particular, the Iceland plume in the NE Atlantic (NEA) could have been instrumental in facilitating the breakup between Europe and Laurentia in the earliest Eocene. Here we present an open access three-dimensional density model of the NEA crust and uppermost mantle that is consistent with previously un-integrated available data. We propose that high-density anomalies in the crust represent the preserved modifications of the lithosphere in consequence of the plate’s journey over the hot mantle plume. Besides, low-density anomalies in the uppermost mantle would represent the present-day effect of the mantle plume and its interaction with the mid-ocean ridges. Overall, the model indicates that the presence of the plume together with the pre-existing crustal configuration controlled the timing, mechanisms and localization of the NEA breakup.

• Pichel, Leonardo Muniz; Huismans, Ritske Sipke; Gawthorpe, Rob; Faleide, Jan Inge & Theunissen, Thomas Louis Roger Dominique (2022). Coupling Crustal-Scale Rift Architecture With Passive Margin Salt Tectonics: A Geodynamic Modeling Approach. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 127(11). doi: 10.1029/2022JB025177. Fulltekst i vitenarkiv Vis sammendrag

  Continental rifted margins are often associated with widespread, thick evaporite (i.e., salt) deposits and pronounced salt tectonics. The majority of salt basins formed during the latest stages of rifting, prior to continental breakup. We use 2D thermo-mechanical finite element modeling of lithospheric extension to investigate the interplay between rifted margin architecture, late syn-rift salt deposition, and post-rift salt tectonics. We focus on four different types of continental margins: (a) narrow, (b) intermediate, (c) wide, and (d) ultra-wide margins. We evaluate the: (a) interplay between laterally variable syn-rift extension, salt deposition and salt tectonics, (b) influence of syn-rift basin architecture on post-rift salt flow, (c) spatial and temporal distribution of salt-related structural domains, and (d) contrasting styles of salt tectonics for different margin types. Narrow and intermediate margins form partially isolated salt basins associated with prominent base-salt relief, limited translation but significant diapirism, and minibasin development. Wide and ultra-wide margins form wide salt basins with subtle base-salt relief that results in significant seaward salt expulsion and overburden translation. These wide margins demonstrate significant updip extension with the development of post-rift normal faults and rollovers, mid-margin translation associated with complex diapirism and downdip diapir shortening. All margins contain a distal salt nappe that varies in width and complexity. We also test the effect of different salt viscosities, relative post-salt progradation rates, and pre-salt sediment thicknesses. The results are comparable to several examples of salt-bearing rifted margins and improve our understanding of their dynamics and on the controls on their salt tectonics variability.

• Serck, Christopher Sæbø; Braathen, Alvar; Hassaan, Muhammad; Faleide, Jan Inge; Riber, Lars & Messager, Grégoire [Vis alle 7 forfattere av denne artikkelen] (2022). From metamorphic core complex to crustal scale rollover: Post-Caledonian tectonic development of the Utsira High, North Sea. Tectonophysics. ISSN 0040-1951. 836. doi: 10.1016/j.tecto.2022.229416. Fulltekst i vitenarkiv
• Corseri, Romain; Planke, Sverre; Gelius, Leiv Jacob; Faleide, Jan Inge; Senger, Kim & Abdelmalak, Mohamed Mansour (2022). Magnetotelluric image of a hyper-extended and serpentinized rift system. Earth and Planetary Science Letters. ISSN 0012-821X. 602. doi: 10.1016/j.epsl.2022.117914. Fulltekst i vitenarkiv Vis sammendrag

  Magnetotelluric (MT) data can image the Earth's electrical resistivity down to the mantle but are rarely used for investigation of offshore rifted margins. In such settings, the lower crust and upper mantle are altered by distinct tectono-thermal processes but often display similar seismic velocities and densities. By integrating resistivity models from MT data, we aim at resolving such ambiguity. Here, 3D inversion of long period, marine MT data (1 – 3000 s) is performed on 104 receivers located along two, ∼300 km long transects in the SW Barents Sea. The resolving power of MT data is assessed with synthetic tests in an archetypal rift system where ample crustal thickness variation occurs. The results highlight that our MT data sense the transition from necking to hyper-extended domain where the crust (<10 km) is not recovered by 3D inversion. In the Bjørnøya Basin – the northernmost member of a hyper-extended Cretaceous basin chain in the NE Atlantic – we combine seismic interpretation and MT inversion models to assign resistivity properties at two depth intervals: (1) 0.1-1 Ωm within Lower Cretaceous marine shales buried at 10-15 km depth (2) 1-10 Ωm within the uppermost mantle. Based on a fluid-rock model, we emphasize that seawater as a sole pore fluid phase is not conductive enough to explain such high bulk conductivities at both intervals. A 25% serpentinization of mantle rocks can account for a fivefold rise in salinity of the residual fluid and is compatible with bulk resistivity, density, and seismic velocities in the Bjørnøya Basin. Such high-salinity fluid can ascend and mix with seawater in pore spaces of the sediments, supporting our model of saline fluid circulation in hyper-extended basins. In conclusion, electrical resistivity models can disambiguate interpretation of deep structures in rifted margin by detecting saline fluids from partial serpentinization, intermixing with seawater in overlying marine sediments.

• Gabrielsen, Roy Helge; Roberts, David; Gjelsvik, Tone; Sygnabere, Trond Olav; Hassaan, Muhammad & Faleide, Jan Inge (2022). Double-folding and thrust-front geometries associated with the Timanian and Caledonian orogenies in the Varanger Peninsula, Finnmark, North Norway. Journal of the Geological Society. ISSN 0016-7649. 179(6). doi: 10.1144/jgs2021-153. Fulltekst i vitenarkiv Vis sammendrag

  On Varanger Peninsula, the roughly NW–SE-trending Trollfjorden–Komagelva Fault Zone separates Neoproterozoic successions that accumulated in a shallow-marine platformal domain to the SW of the fault from deepmarine basinal to deltaic sediments to the NE. In Ediacaran time the fault scarp acted as a buttress in a period of basinal inversion during the top-to-the-SW, contractional Timanian orogeny. During the subsequent, top-to-the-SE to -ESE, polyphase Caledonian orogenesis the fault acted as a dextral strike-slip megafracture and lateral ramp. In the northeastern terrane, Timanian and Caledonian fold interference has produced several examples of double-folding and intersecting cleavages. In the southwestern terrane, the Lower Allochthon Gaissa Thrust Belt overlies the Parautochthon, below which a 45 km long deformation front has been mapped. Tectonic shortening within this frontal zone varies from top-to-the-SSE in the west to topto-the-ESE in the east. Imbricate thrust sheets disrupt the succession in the northeastern terrane, below which a floor décollement is speculated to emerge as a frontal fault along a prominent footwall of the precursor fault that acted on the seabed in outermost Varangerfjorden. By use of potential field data, the Caledonian structures on Varanger can be followed to the north into the Barents Sea where the nappe pile in the pre-Carboniferous basement reaches a thickness of several kilometres.

• Abdelmalak, Mohamed Mansour; Gac, Sebastien; Faleide, Jan Inge; Shephard, Grace; Tsikalas, Filippos & Polteau, Stephane [Vis alle 8 forfattere av denne artikkelen] (2022). Quantification and Restoration of the Pre-Drift Extension Across the NE Atlantic Conjugate Margins During the Mid-Permian-Early Cenozoic Multi-Rifting Phases. Tectonics. ISSN 0278-7407. 42(1). doi: 10.1029/2022TC007386. Fulltekst i vitenarkiv Vis sammendrag

  The formation of the NE Atlantic conjugate margins is the result of multiple rifting phases spanning from the Late Paleozoic and culminating in the early Eocene when breakup was accompanied with intense magmatic activity. The pre-breakup configuration of the NE Atlantic continental margins is controlled by crustal extension, magmatism, and sub-lithospheric processes, all of which need to be quantified for the pre-breakup architecture to be restored. Key parameters that need to be extracted from the analysis of crustal structures and sediment record include stretching factors, timing of rifting phases, and nature of the deep crustal structures. The aim of this study is to quantify the pre-drift extension of the NE Atlantic conjugate margins using interpreted crustal structure and forward basin modeling. We use a set of eight 2D conjugate crustal transects and corresponding stratigraphic models, constrained from an integrated analysis of 2D and 3D seismic and well data. The geometry and thickness of the present-day crust is compared to a reference thickness which has experienced limited or no crustal extension since Permian time allowing the quantification of crustal stretching. Based on the eight conjugate crustal transects, the total pre-drift extension is estimated to range between 181 and 390 km with an average of 270–295 km. These estimates are supported by the results of forward basin modeling, which predict total extension between 173 and 325 km, averaging 264 km. The cumulative pre-drift extension estimates derived from basin modeling are in turn used to calculate the incremental crustal stretching factors at each of the three main rifting phases between the conjugate Greenland-Norwegian margins. The mid-Permian early Triassic rifting phase represents 32% of the total extension, while the equivalent values are 41% for the mid-Jurassic to mid-Cretaceous and 27% for the Late Cretaceous-Paleocene rifting phases. These values are used to establish and present at first, a full-fit palinspastic plate kinematic model for the NE Atlantic since the mid-Permian and will be the base for future work on more elaborated models in order to build accurate paleogeographic and tectonic maps.

• Osmond, Johnathon; Mulrooney, Mark Joseph; Holden, Nora; Skurtveit, Elin; Faleide, Jan Inge & Braathen, Alvar (2022). Structural traps and seals for expanding CO<inf>2</inf> storage in the northern Horda platform, North Sea. American Association of Petroleum Geologists Bulletin. ISSN 0149-1423. 106(9), s. 1711–1752. doi: 10.1306/03222221110. Fulltekst i vitenarkiv Vis sammendrag

  Development and maturation of geological carbon dioxide (CO2) storage projects along the Norwegian Continental shelf is ongoing, but even more storage locations are needed to reach climate mitigation goals by 2050. To augment the future Aurora injection site and expand CO2 storage in the northern Horda platform of the North Sea, the region’s potential must be assessed. Here, we leverage the latest wellbore and seismic data to map storage aquifers, identify structural traps, and assess possible top and fault seals associated with Lower and Upper Jurassic storage complexes in four major fault blocks. Our results indicate that both storage complex aquifers are preserved throughout the study area. From our minimum size criteria, we have identified a total of 95 Lower and 64 Upper Jurassic traps representing approximately 2.37 × 1010 and 5.80 × 1010 m3 in gross rock volume, respectively. Mapping, modeling, and formation pressure analyses suggest that top seals are sufficiently thick over the majority of structural traps and provide vertical pressure barriers between storage aquifers. Across-fault juxtaposition seals are abundant but dominate the Upper Jurassic storage complexes. Lower Jurassic aquifers, however, are often upthrown against Upper Jurassic aquifers, but apparent across-fault pressure differentials and shale gouge ratio values >0.15 correlate, suggesting fault rock membrane seal presence. Aquifer self-juxtapositions, however, are likely areas with poor fault seal. Overall, our work provides added support that the northern Horda platform represents a promising location for CO2 storage expansion, carrying the potential to become a future storage hub in the North Sea.

• Tsikalas, Filippos; Cala, Juan Camilo Meza; Abdelmalak, Mohamed Mansour; Faleide, Jan Inge & Brekke, Harald (2022). Lofoten Composite Tectono-Sedimentary Element, Norwegian Rifted Margin, Norwegian Sea. Geological Society of London Memoirs. ISSN 0435-4052. 57. doi: 10.1144/M57-2021-43. Fulltekst i vitenarkiv Vis sammendrag

  The Lofoten Rifted Margin is a composite tectono-sedimentary element (CTSE), located offshore northern Norway, and comprises the northernmost part of the Norwegian Sea margin at its transition to the West Barents Sea margin. We refine the late Paleozoic–early Cenozoic evolution of the margin with emphasis on the late Mesozoic–early Cenozoic rift phases, and we provide new and better-refined structural elements for the area. Distinct along-margin segmentation is evident and is imposed by transfer zones/systems that reflect the structural inheritance. These divide the study area into three main margin segments, namely the Lofoten, Vesterålen and Andøya segments, that are accounted for by observed along-margin tectonostratigraphic changes and are briefly viewed in a conjugate margin setting. Confirmed and potential plays within five main reservoir groups are also described and evaluated.

• Pichel, Leonardo Muniz; Huismans, Ritske Sipke; Gawthorpe, Rob; Faleide, Jan Inge & Theunissen, Thomas Louis Roger Dominique (2022). Late-syn- to post-rift salt tectonics on wide rifted margins—Insights from geodynamic modeling. Tectonics. ISSN 0278-7407. 41(8). doi: 10.1029/2021TC007158. Fulltekst i vitenarkiv Vis sammendrag

  Rifted margins are often associated with widespread and thick evaporite (salt) deposits and pronounced salt tectonics. The largest salt basins formed during the latest stages of rifting, immediately prior to continental breakup. Salt tectonics along these rifted margins commonly exhibit structural domains characterized by gravity-driven updip extension, translation, downdip shortening, and salt nappe advance. The precise spatial and temporal links between these structural processes, their relative contributions and dynamics are still a topic of debate on many margins. We use 2D thermo-mechanically coupled finite-element modeling of lithospheric extension to investigate the evolution of salt tectonics along wide rifted margins and the interplay between rifting and post-rift deformation. The models integrate lithospheric extension with post-rift salt tectonics using a geodynamically self-consistent approach where the geometries of the lithosphere and salt basins are not prescribed. They confirm that wide salt-bearing rifted margins are characterized by gravity-driven updip extension and downdip shortening, but also that syn-depositional salt flow and salt stretching occurs in their distal portions prior to and during continental breakup. This produces widening of the basin and emplacement of a salt nappe over newly formed oceanic crust. Post-rift updip extension is mostly balanced by downdip diapir shortening, all related to Couette flow. The salt nappe initiated by late syn-rift stretching advances further by post-rift pressure-driven Poiseuille salt flow so that its final width is a product of both processes. The results can be directly compared to examples from various salt-bearing rifted margins and improve our understanding of their enigmatic genesis and evolution.

• Bellwald, Benjamin; Planke, Sverre; Polteau, Stephane; Lebedeva-Ivanova, Nina; Faleide, Jan Inge & Zengaffinen-Morris, Sunniva Margrethe [Vis alle 8 forfattere av denne artikkelen] (2021). Characterization of a glacial paleo-outburst flood using high-resolution 3-D seismic data: Bjørnelva River Valley, SW Barents Sea. Journal of Glaciology. ISSN 0022-1430. 67(263), s. 404–420. doi: 10.1017/jog.2020.115. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Proglacial braided river systems discharge large volumes of meltwater from ice sheets and transport coarse-grained sediments from the glaciated areas to the oceans. Here, we test the hypothesis if high-energy hydrological events can leave distinctive signatures in the sedimentary record of braided river systems. We characterize the morphology and infer a mode of formation of a 25 km long and 1–3 km wide Early Pleistocene incised valley recently imaged in 3-D seismic data in the Hoop area, SW Barents Sea. The fluvial system, named Bjørnelva River Valley, carved 20 m deep channels into Lower Cretaceous bedrock at a glacial paleo-surface and deposited 28 channel bars along a paleo-slope gradient of ~0.64 m km −1 . The landform morphologies and position relative to the paleo-surface support that Bjørnelva River Valley was formed in the proglacial domain of the Barents Sea Ice Sheet. Based on valley width and valley depth, we suggest that Bjørnelva River Valley represents a braided river system fed by violent outburst floods from a glacial lake, with estimated outburst discharges of ~160 000 m 3 s −1 . The morphological configuration of Bjørnelva River Valley can inform geohazard assessments in areas at risk of outburst flooding today and is an analogue for landscapes evolving in areas currently covered by the Greenland and Antarctic ice sheets.

• Hassaan, Muhammad; Faleide, Jan Inge; Gabrielsen, Roy Helge & Tsikalas, Filippos (2021). Effects of basement structures and Carboniferous basin configuration on evaporite distribution and the development of salt structures in Nordkapp Basin, Barents Sea—Part I. Basin Research. ISSN 0950-091X. 33(4), s. 2474–2499. doi: 10.1111/bre.12565. Fulltekst i vitenarkiv Vis sammendrag

  Potential field data, reprocessed regional 2D seismic reflection profiles and 3D seismic tied to wells were used to study the late Devonian-Permian development of the Nordkapp Basin in Barents Sea. The composite basin can be subdivided into the northeastern, central and southwestern segments that developed above a basement that contains elements of the Timanian and Caledonian regimes. The transition between the Timanian and Caledonian structures is positioned below the central basin segment. The rheological properties, locations, orientations and interaction of inherited structures together with two subsequent extensional phases, defined the presalt rift architecture and gave rise to seven subbasins within Nordkapp Basin. During the late Devonian-early Carboniferous NE-SW oriented extension, the basin consisted of two regional half-grabens (northern and southern) separated by an interbasin ridge. During the late Carboniferous, the shift of extension direction to NW-SE orientation reshaped the two regional half-grabens. In particular, an interbasin transfer zone divided the northern regional half-graben by separating its hinged-margin portion (incipient northeastern segment) from the deeper part (incipient central segment). At the same time, the elevated interbasin ridge separated the incipient central and southwestern segments. Internally within the seven subbasins, the evolving structural elements including cross-cutting master faults and structural highs have influenced the deposition and character of the Pennsylvanian-lower Permian layered evaporite sequence and the distribution of subsequent salt structures. We suggest that the synrift to early postrift processes, relative depth of each subbasin, arrangement of the structural highs and depositional palaeo-environment all controlled the thickness and facies of the layered evaporite sequence. The latter in combination with the presalt architecture comprised a laterally varying in thickness and character substratum that during the earliest Triassic influenced the sediment routings and deposition of the progradational system arriving in Nordkapp Basin. The study outcomes are pertinent and applicable to other salt-influenced rift basins worldwide.

• Lasabuda, Amando Putra Ersaid; Johansen, Nora Johanne Synnestvedt; Laberg, Jan Sverre; Faleide, Jan Inge; Senger, Kim & Rydningen, Tom Arne [Vis alle 9 forfattere av denne artikkelen] (2021). Cenozoic uplift and erosion of the Norwegian Barents Shelf – A review. Earth-Science Reviews. ISSN 0012-8252. 217. doi: 10.1016/j.earscirev.2021.103609. Fulltekst i vitenarkiv Vis sammendrag

  Uplift and erosion are complex phenomena in terms of their governing processes, precise timing and exact magnitude. The intricate relationship between different geodynamic processes leading to uplift may increase uncertainties in estimating spatial and temporal patterns. Sediment distribution from uplifted (and eroded) topography and the corresponding paleoenvironmental reconstructions require reliable constrains. The Barents Shelf provides a unique arena to study uplift and erosion due to extensive seismic and well data attributed to high petroleum activity. This particular interest has led to a voluminous literature about this topic over the last three decades. Here, we present the current status of the Cenozoic uplift and erosion on the Norwegian Barents Shelf by reviewing the key terminology, its tectonic history and paleoenvironment, methods in quantifying uplift and erosion, as well as timing and possible mechanisms. Our new erosion maps show an increase in net erosion to the north and northeast that represents key underlying concepts, including tectonic (compression, rift-flank uplift, thermo-mechanical coupling, mantle dynamics, flexural/isostatic response) as well as magmatic and glacial processes. We have integrated pre-glacial and glacial net erosion using the mass balance method and added our results from sonic velocity, interval velocity and sandstone diagenesis methods to the new maps. This review shows that discrepancies of net erosion estimates from different methods are on the order of 500 m. Finally, we identify research gaps for future studies, with implications for the Barents Shelf and other uplifted basins worldwide

• Würtzen, Camilla Louise; Osmond, Johnathon; Faleide, Jan Inge; Nystuen, Johan Petter; Anell, Ingrid & Midtkandal, Ivar (2021). Syn- to post-rift alluvial basin fill: seismic stratigraphic analysis of Permian-Triassic deposition in the Horda Platform, Norway. Basin Research. ISSN 0950-091X. doi: 10.1111/bre.12644. Fulltekst i vitenarkiv
• Gernigon, Laurent; Zastrozhnov, Dmitrii; Planke, Sverre; Manton, Ben; Abdelmalak, Mohamed Mansour & Olesen, Odleiv [Vis alle 9 forfattere av denne artikkelen] (2021). A digital compilation of structural and magmatic elements of the mid-Norwegian continental margin (Version 1.0). Norwegian Journal of Geology. ISSN 2387-5844. 101. doi: 10.17850/njg101-3-2. Fulltekst i vitenarkiv Vis sammendrag

  A new generation of long-offset 2D seismic reflection lines, 2D-cubed seismic volumes, extensive 3D seismic surveys, high-resolution potential field data, and exploration wells has resulted in improved geological mapping of the Mid–Norwegian continental margin. Over the past decade, we have conducted an integrated seismic-gravity-magnetic interpretation of the entire volcanic rifted margin. This work has resulted in the reassessment and identification of several structural and magmatic elements. The elements have been classified and assembled in a regional and digital geological map compilation that documents both 1) the pre-breakup and 2) the syn-to post-breakup outlines of the volcanic rifted margin. The 1:1,000,000 digital compilation includes layers with structural elements defined at the Base Cretaceous, Base Paleogene and Mid–Miocene levels, as well as major detachment faults. The main sets of faults identified in the sedimentary basins were active during the Late Jurassic–Early Cretaceous and Late Cretaceous–Paleocene rifting episodes before 2 2 the earliest Eocene continental breakup. In the oceanic province, magnetic anomaly chrons and oceanic fracture zones have been revised based on up-to-date aeromagnetic data. The syn-to post-breakup elements feature late Paleocene–early Eocene volcanic facies units, which were mapped using seismic volcanostratigraphy and igneous seismic geomorphology. We have further mapped the distribution of igneous sills and associated hydrothermal vent complexes, compressional domes, arches, slides and glacial depocentres. The project datasets include layers in standard GIS formats (e.g., shapefiles) as well as a ready-to-use QGIS project that includes embedded files, dedicated colour codes and standards. This open-source compilation is intended for exploration and academic purposes. The 1.0 version of this compilation will be periodically updated and revised depending on the availability of new data and scientific results.

• Hassaan, Muhammad; Faleide, Jan Inge; Gabrielsen, Roy Helge; Tsikalas, Filippos & Grimstad, Silje (2021). Interplay between base-salt relief, progradational sediment loading and salt tectonics in the Nordkapp Basin, Barents Sea – Part II. Basin Research. ISSN 0950-091X. 33(6), s. 3256–3294. doi: 10.1111/bre.12602. Fulltekst i vitenarkiv Vis sammendrag

  Reprocessed, regional, 2D seismic reflection profiles, 3D seismic volumes and well data (exploration and shallow boreholes), combined with 2D structural restorations and 1D backstripping were used to study the post-salt evolution of the Nordkapp Basin in Barents Sea. The post-salt evolution took place above a pre-salt basement and basin configuration affected by multiple rift events that influenced the depositional facies and thickness of Pennsylvanian-lower Permian-layered evaporite sequence. Initially, regional mid-late Permian extension reactivated pre-salt Carboniferous faults, caused minor normal faulting in the Permian strata and triggered slight salt mobilization towards structural highs. The main phase of salt mobilization occurred during earliest Triassic when thick and rapidly prograding sediments entered from the east into the Nordkapp Basin. In the early-mid-Triassic, the change in the direction of progradation and sediment entry-points shifted to the NW led to rotation of the earlier-formed mini-basins and shift of dominant salt evacuation direction to the south. The prograding sediment influx direction, sediment transport velocity and thickness influenced the dynamics of the early to late passive diapirism, salt expulsion and depletion along the strike of the basin. The basin topography resulting from salt highs and mini-basin lows strongly affected the Triassic progradational fairways and determined the distinct sediment routing patterns. Minor rejuvenation of the salt structures and rotation of the mini-basins took place at the Triassic–Jurassic transition, due to far-field stresses caused by the evolving Novaya Zemlya fold-and-thrust belt to the east. This rejuvenation influenced the sediment dispersal routings and caused formation of dwarf secondary mini-basins. The second and main rejuvenation phase took place during likely early-mid-Eocene when propagated far-field stresses from the transpressional Eurekan/Spitsbergen orogeny to the NW inverted pre-salt normal faults, reactivated the structural highs and rejuvenated the salt structures. The studied processes and study outcomes can be applicable to other evaporite-dominated basins worldwide.

• Shulgin, Alexey A; Faleide, Jan Inge; Mjelde, Rolf; Breivik, Asbjørn Johan & Huismans, Ritske Sipke (2021). Crustal domains in the Western Barents Sea. Geophysical Journal International. ISSN 0956-540X. 221(3), s. 2155–2169. doi: 10.1093/GJI/GGAA112. Fulltekst i vitenarkiv Vis sammendrag

  The crustal architecture of the Barents Sea is still enigmatic due to complex evolution during the Timanian and Caledonian orogeny events, further complicated by several rifting episodes. In this study we present the new results on the crustal structure of the Caledonian–Timanian transition zone in the western Barents. We extend the work of Aarseth et al. (2017), by utilizing the seismic tomography approach to model Vp, Vs and Vp/Vs ratio, combined with the reprocessed seismic reflection line, and further complemented with gravity modelling. Based on our models we document in 3-D the position of the Caledonian nappes in the western Barents Sea. We find that the Caledonian domain is characterized by high crustal reflectivity, caused by strong deformation and/or emplacement of mafic intrusions within the crystalline crust. The Timanian domain shows semi-transparent crust with little internal reflectivity, suggesting less deformation. We find, that the eastern branch of the earlier proposed Caledonian suture, cannot be associated with the Caledonian event, but can rather be a relict from the Timanian terrane assemblance, marking one of the crustal microblocks. This crustal block may have an E–W striking southern boundary, along which the Caledonian nappes were offset. A high-velocity/density crustal body, adjacent to the Caledonian–Timanian contact zone, is interpreted as a zone of metamorphosed rocks based on the comparison with global compilations. The orientation of this body correlates with regional gravity maxima zone. Two scenarios for the origin of the body are proposed: mafic emplacement during the Timanian assembly, or massive mafic intrusions associated with the Devonian extension.

• Tsikalas, Filippos; Blaich, Olav Antonio; Faleide, Jan Inge & Olaussen, Snorre (2021). Stappen High–Bjørnøya Tectono-Sedimentary Element, Barents Sea. Geological Society of London Memoirs. ISSN 0435-4052. 57. doi: 10.1144/M57-2016-24. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Planke, Sverre; Berndt, Christian; Huismans, Ritske Sipke; Faleide, Jan Inge; Bünz, Stefan & Millett, John [Vis alle 8 forfattere av denne artikkelen] (2025). Understanding Volcanic Rifted Margins and Paleoclimate Implications from Scientific Drilling in the NE Atlantic. doi: https:/ui.adsabs.harvard.edu/abs/2024AGUFMPP44A..02P/abstract. Fulltekst i vitenarkiv
• Planke, Sverre; Bünz, Stefan; Berndt, Christian; Zarikian, Carlos A. Alvarez; Lebedeva-Ivanova, Nina N. & Stokke, Henrik Henriksen [Vis alle 18 forfattere av denne artikkelen] (2025). The Ocean-Continent Transition of the Northern Vøring Margin from New High-Resolution 2D Seismic and IODP Expedition 396 Data. Fulltekst i vitenarkiv
• Lasabuda, Amando; Salles, Tristan; Zahirovic, Sabin; Shephard, Grace; Faleide, Jan Inge & Muller, Dietmar (2025). Sedimentary source-to-sink of the northern Barents Shelf and its implication for the opening of the Nansen Basin. doi: https:/zenodo.org/records/16810950. Fulltekst i vitenarkiv Vis sammendrag

  Reconstructing Cenozoic sedimentary source-to-sink in the greater Barents Sea is highly uncertain due to heavily eroded Cenozoic strata during the Quaternary glaciations. This uncertainty led to diverging models of the Barents Shelf paleo-landscape in the Cenozoic, ultimately affecting the accuracy of climate, oceanographic and sediment source-to-sink simulations. The ratio between off-shelf Cenozoic pre-glacial and glacial sediments is relatively higher in the Barents Sea northern continental margin than the western margin. This observation and other studies point to a hypothesis of an elevated terrain of the paleo-northern Barents Sea in the Paleogene-Neogene. However, it is not clear when and how this paleo-topographic high was formed, and how it evolved throughout the Cenozoic. The spatio-temporal pattern of the catchment area supplying sediments to the evolving ultra-slow seafloor spreading of the Nansen Basin remains enigmatic. Moreover, the impact of rift-flank uplift on the sediment routing from the source to the sink area is also unclear, considering a relatively sharp boundary between the continental and oceanic plates in the study area. Here we used Badlands forward modelling coupled with GPlates tectonic reconstructions to simulate the basin-filled stratigraphy in the Nansen Basin and the landscape evolution of the northern Barents Sea. We compared the numerical outcomes with the seismic data from and across the continental margin. Our simulations shed light on constraining the opening configuration of the Nansen Basin, reflecting interactions between tectonic (deeper mantle processes, isostasy), climatic and surface processes (sediment erosion, transport and deposition).

• Shephard, Grace; Abdelmalak, Mohamed Mansour; Faleide, Jan Inge; Clennett, Edward; Gac, Sebastien & Zahirovic, Sabin [Vis alle 9 forfattere av denne artikkelen] (2025). A basin-to-plate deformable plate framework to capture the multi-phase rifting of the Northeast Atlantic. Fulltekst i vitenarkiv
• Nygaard, Madeleine Skov; Planke, Sverre; Berndt, Christian; Zastrozhnov, Dmitry; Faleide, Jan Inge & Jones, Morgan Thomas [Vis alle 18 forfattere av denne artikkelen] (2025). Mimir High Core-log-seismic Integration. Fulltekst i vitenarkiv
• Lasabuda, Amando P. E.; Salles, Tristan; Shephard, Grace; Zahirovic, Sabin; Faleide, Jan Inge & Muller, Dietmar (2024). Impact of landscape evolution on the ocean circulation and glaciation: A forward modelling of basin and landscape dynamics, northern Barents Sea, Norwegian Arctic. Fulltekst i vitenarkiv Vis sammendrag

  Basin and landscape dynamics play a key role in oceanographic and climate evolution, such as connecting two major oceans and establishing a paleotopographic high at the onset of large-scale glaciations. The Barents Sea is an underexplored ocean gateway (also known as the Barents Seaway) connecting the Atlantic and Arctic oceans. However, unlike the Fram Strait Gateway, its formation over the past 66 Myr in the Cenozoic remains unclear. Several studies suggest that a paleo-topographic high was formed in the northern Barents Sea as early as the Miocene (c. 23 Ma), preconditioning an ice cap formation that led to the development of large-scale glaciation in the Northern Hemisphere (c. 2.7 Ma). However, the exact timing of this mountainous terrain remains uncertain. Here we used badlands, an open-source basin and landscape forward modelling framework to simulate the evolution of basin and landscape in the northern Barents Sea in the Cenozoic. To constrain the geometry of the oceanic basin for the sediment filling to the Nansen Basin we take advantage of GPlates. We then test different scenarios of catchment models and their associated sediment transport and accumulation in a source-to-sink context. Paleo-precipitations, sea-level fluctuations and tectonic/flexural response are used to understand the controlling parameters. The numerical results are then compared with seismic profiles and available well and core data. This study contributes to constraining the spatio-temporal pattern of the northern Barents Shelf landscape morphology, which can be applied in other formerly glaciated areas.

• Lasabuda, Amando; Tristan, Salles; Zahirovic, Sabin; Shephard, Grace; Faleide, Jan Inge & Muller, Dietmar (2024). Cenozoic Sediment Multi-source-to-sink in the Barents Sea: Insights from Stratigraphic Forwad Modelling. Fulltekst i vitenarkiv
• Wong, Po Wan; Midtkandal, Ivar & Faleide, Jan Inge (2024). Early Paleogene rift-to-drift transition at the NE Atlantic – new insights from rift propagation and paired extension-compression. Fulltekst i vitenarkiv
• Planke, Sverre; Berndt, Christian; Bünz, Stefan; Huismans, Ritske Sipke; Faleide, Jan Inge & Svensen, Henrik Hovland [Vis alle 11 forfattere av denne artikkelen] (2024). Understanding Volcanic Rifted Margins and Paleoenvironment by Scientific Drilling in the NE Atlantic. Fulltekst i vitenarkiv
• Jones, Morgan; Rooney, Alan; Zuchuat, Valentin; Turner, Holly; Frieling, Joost & Mather, Tamsin [Vis alle 14 forfattere av denne artikkelen] (2024). Volcanic proxies from the northern Pangean margin across the Permian-Triassic boundary: Evidence of intermittent Siberian Traps activity. Fulltekst i vitenarkiv
• Osmond, Johnathon; Faleide, Jan Inge & Braathen, Alvar (2024). Quaternary seismostratigraphic framework and pockmarks within the Norwegian Channel, northern North Sea. Fulltekst i vitenarkiv Vis sammendrag

  https://doi.org/10.3997/2214-4609.2024101728 Summary: The Norwegian Channel is host to a tremendous amount of activity related to the petroleum industry in the northern North Sea, but the area is now receiving new attention related to the ongoing energy transition. Previous workers developed a seismostratigraphic framework for sediments above the Upper Regional Unconformity (URU) based on legacy 2D seismic data and core from the BH8903 geotechnical wellbore located above the Troll East field, but regional horizon surface maps remain absent from the literature. Additionally, sediments within the channel preserve both seafloor and buried pockmarks. While previous studies provided maps of pockmark areal densities and explored a wide range of possible controls over pockmark distributions within the Norwegian Channel, work can be improved by using data with greater coverage and quality. For this work, we have utilised a large, modern 3D seismic survey, wellbore data, and the legacy seismostratigraphic framework in order to produce novel Quaternary seismic horizons surface maps and updated pockmark distribution maps within the Norwegian Channel. Overall, our results have utility for basin studies and hydrocarbon exploration within the region, but also supports work for local CO2 storage and offshore wind developments, which require the mapping of overburden stratigraphy and potential geohazards

• Osmond, Johnathon L.; Holden, Nora; Mulrooney, Mark Joseph; Skurtveit, Elin; Faleide, Jan Inge & Braathen, Alvar (2024). Beyond Aurora and Smeaheia; structural traps and seals for additional CO2 storage within Jurassic Horda Platform aquifers. Fulltekst i vitenarkiv Vis sammendrag

  Summary: Geological carbon dioxide sequestration (CCS) is a relatively small, yet viable solution for reducing CO2 emissions as we approach the year 2050. This is particularly true for emissions resulting from industrial operations that likely cannot be rendered into emissionless processes, such as cement production. The Aurora CO2 storage site located in the northern Horda Platform of the Norwegian North Sea is part of the Longship project, one of the world’s first to demonstrate the full CCS value chain. Injection and containment of CO2 is scheduled take place by 2024 within the Lower Jurassic storage complex comprised of Dunlin Gp siliciclastic saline aquifers capped by mudrocks and shales. While current well tests at Aurora suggest favorable conditions for injection rates of 5 megatons per year, more storage sites are required and under development. Roughly 40 km east of Aurora, a second CO2 storage exploitation license has recently been awarded in the Smeaheia area. In contrast to Aurora, injection is likely to transpire within an Upper Jurassic storage complex, with aquifers of the Viking Gp overlain by fine-grained rocks of the Viking Gp and Lower Cretaceous Cromer Knoll Gp, similar to parts of the nearby Troll field. While storage complexes in both areas are fairly well-established, less is certain about whether or not the same concepts could be utilized throughout greater northern Horda Platform, and what other areas have potential. In order to address the possibility of expanding the northern Horda Platform into a larger CO2 storage hub, we utilized 3D seismic reflection and wellbore data to study the Lower and Upper Jurassic storage complexes with a regional structural trap and seal approach. Here, we show Lower and Upper Jurassic storage aquifers presence, and highlight the array of fault-bound structural traps. We also present top seal thickness variations and evidence of their effectiveness, where we consider fine-grained Cretaceous Shetland Gp and Paleocene Rogaland Gp rock as additional seals of the Upper Jurassic storage complex. Furthermore, because faults have generally been observed to provide barriers or conduits to across-fault fluid migration, we have assessed the lateral fault seals critical for containing injected CO2 within the mapped traps. While across-fault juxtaposition seals are of high confidence and are critical for the Upper Jurassic storage complex, we go on to illustrate that membrane seals are also necessary for success in the Lower Jurassic storage complex, but both pressure data and empirical modeling imply their seal effectiveness. Finally, as the Aurora and Smeaheia storage sites develop and technical work continues to be carried out, the results from this study suggest that the Upper and Lower Jurassic storage complexes could be utilized to develop northern Horda Platform CO2 into a larger storage hub.

• Osmond, Johnathon; Holden, Nora; Cruz, Erika H de La; Würtzen, Camilla Louise; Skurtveit, Elin & Faleide, Jan Inge [Vis alle 7 forfattere av denne artikkelen] (2024). Containment derisking of a potential CO2 storage hub in the Horda Platform, Norwegian North Sea. Fulltekst i vitenarkiv
• Osmond, Johnathon; Holden, Nora; Würtzen, Camilla Louise; Cruz, Erika H de La; Skurtveit, Elin & Faleide, Jan Inge [Vis alle 7 forfattere av denne artikkelen] (2024). Distribution of Upper Jurassic–Upper Cretaceous seals in the northern Horda Platform: considerations for CO2 storage within the Smeaheia area (EL002). Fulltekst i vitenarkiv Vis sammendrag

  Summary: On the road towards achieving climate mitigation goals by 2050, geological carbon dioxide sequestration (CCS) will play a key role in reaching net-zero greenhouse gas emissions globally. In the northern Horda Platform of the Norwegian North Sea, the developing Aurora CO2 storage site will be an early contributor to the solution. There, injection of 1.5 megatonnes of CO2 per year or more into a Lower Jurassic storage complex (Dunlin Group) will commence in 2024. However, other storage locations in the northern Horda Platform appear to be on the rise. Of note is the EL002 storage exploitation license in the Smeaheia fault block, which offers an attractive Upper Jurassic storage complex comprised of Viking Group sandstone storage formations (saline aquifer) and younger seals. The Alpha 3-way closure bounded by the Vette fault zone is one of several prospects that could be employed for injected CO2 containment. However, the heterolithic the Draupne Formation, Cromer Knoll Group, and Shetland Group (Upper Jurassic through Upper Cretaceous) must serve as top and lateral (fault) seals, which have not been well studied until recently. In this contribution, we show the distribution of these seals utilizing the latest 3D seismic and wellbore data for detailed interpretation and modeling, while also comparing our observations to the Troll East field along the Tusse fault zone, whose trap and seal provides an excellent analog with respect to CO2 storage within the Alpha prospect. Moreover, we preview new cuttings XRD data coupled with corresponding wireline logs in order to help correlate regional facies changes, particularly their relation to key Alpha trap contacts give that quartz-, carbonate-, and clay-rich facies vary vertically and horizontally. Overall, this study highlights considerations for EL002, as well as the continued development of the northern Horda Platform into a future CO2 storage hub in the North Sea.

• Nygaard, Madeleine Skov; Planke, Sverre; Berndt, Christian; Zastrozhnov, Dmitry; Faleide, Jan Inge & Jones, Morgan Thomas [Vis alle 24 forfattere av denne artikkelen] (2024). PALMAR – Paleogene Basin Development on the Vøring and Møre Margins. Fulltekst i vitenarkiv
• Nygaard, Madeleine Skov; Planke, Sverre; Berndt, Christian; Zastrozhnov, Dmitry; Faleide, Jan Inge & Jones, Morgan Thomas [Vis alle 24 forfattere av denne artikkelen] (2024). IODP Exp. 396 Drilling and High-Resolution 3D Seismic on the Mimir High. Fulltekst i vitenarkiv
• Nygaard, Madeleine Skov; Planke, Sverre; Berndt, Christian; Zastrozhnov, Dmitry; Faleide, Jan Inge & Jones, Morgan Thomas [Vis alle 11 forfattere av denne artikkelen] (2024). Characterization of the Vøring Transform Margin by IODP Exp. 396 Drilling and High-Resolution 3D Seismic on the Mimir High. Fulltekst i vitenarkiv
• Minakov, Alexander; Smirnov, Maxim; Senger, Kim; Betlem, Peter; Faleide, Jan Inge & Helland-Hansen, Anniken [Vis alle 14 forfattere av denne artikkelen] (2024). 3D magnetotelluric survey of a Miocene-Quaternary volcanic province in NW Svalbard. Fulltekst i vitenarkiv
• Osmond, J.L.; Holden, Nora; Mulrooney, Mark Joseph; Skurtveit, Elin; Faleide, Jan Inge & Braathen, Alvar (2023). Beyond Aurora and Smeaheia; structural traps and seals for additional CO2 storage within Jurassic Horda Platform aquifers. Fulltekst i vitenarkiv
• Lasabuda, Amando P. E.; Shephard, Grace; Faleide, Jan Inge; Salles, Tristan & Muller, Dietmar (2023). RECONSTRUCTING THE BARENTS SEAWAY IN THE CENOZOIC – THE BRAVO PROJECT. Fulltekst i vitenarkiv Vis sammendrag

  The Barents Seaway represents an important marine connection between the Atlantic and Arctic oceans. However, how and when precisely the Barents Seaway formed are not very well understood being overshadowed by its neighbor, the Fram Strait Gateway. The Bravo (Barents Sea Evolution) project will address this issue and aims at reconstructing the Barents Seaway paleobathymetry in the Cenozoic. The key challenge is to quantify the spatial distribution and temporal evolution of km-scale vertical movement of Cenozoic uplift and erosion due to glaciations and pre-glacial tectonism. BRAVO approach requires a comprehensive analysis of off-shelf sediment estimation, lithospheric strength, and other mantle-related processes in order to produce a reliable model. BRAVO will use extensive seismic and well data, and utilize numerical modelling technique using pyGPlates software. BRAVO will also test the paleobathymetry reconstructions by simulating the corresponding sediment source-to-sink in the Cenozoic using pyBadlands, an open-source codes for sediment transport, erosion and depositional processes. BRAVO is a Marie Skłodowska-Curie Actions (MSCA) project funded by the European Union’s Horizon Europe and the Research Council of Norway (2023-2026).

• Planke, Sverre; Berndt, Christian; Zarikian, Carlos A. Alvarez; Bünz, Stefan; Zastrozhnov, Dmitrii & Lebedeva-Ivanova, Nina [Vis alle 10 forfattere av denne artikkelen] (2023). The Nature of Outer Highs on Volcanic Rifted Margins: Results from High-Resolution Seismic Data and IODP Drilling on the Vøring Margin, Norwegian Sea. Fulltekst i vitenarkiv
• Planke, Sverre; Lebedeva-Ivanova, Nina; Bünz, Stefan; Binde, Cornelia Mentzoni; Berndt, Christian & Faleide, Jan Inge [Vis alle 11 forfattere av denne artikkelen] (2023). High-resolution core-log-seismic integration and igneous seismic geomorphology of IODP Expedition 396 sites on the mid-Norwegian margin. Fulltekst i vitenarkiv
• Planke, Sverre; Christian, Berndt; Zarikian, Zarikian Alvarez; Huismans, Ritske Sipke; Bünz, Stefan & Faleide, Jan Inge [Vis alle 8 forfattere av denne artikkelen] (2023). Breakup Magmatism and Paleogene Paleoenvironment: Initial Results from IODP Expedition 396 on the Mid-Norwegian Continental Margin. Fulltekst i vitenarkiv
• Osmond, Johnathon; Mulrooney, Mark Joseph; Holden, Nora; Skurtveit, Elin; Faleide, Jan Inge & Braathen, Alvar (2022). Quaternary stratigraphy and pockmark mapping in the Norwegian Channel, northern North Sea. Fulltekst i vitenarkiv
• Shephard, Grace; Faleide, Jan Inge; Gaina, Carmen; Abdelmalak, Mohamed Mansour; Gac, Sebastien & Torsvik, Trond Helge (2022). Building deformable plate models for the Northeast Atlantic. Fulltekst i vitenarkiv
• Osmond, Johnathon; Mulrooney, Mark Joseph; Würtzen, Camilla Louise; Cruz, E. De La; Skurtveit, Elin & Faleide, Jan Inge [Vis alle 7 forfattere av denne artikkelen] (2022). Upper Jurassic through Lower Cretaceous seal characterization in the northern Horda Platform. Fulltekst i vitenarkiv
• Lasabuda, Amando P. E.; Hanssen, Alfred; Laberg, Jan Sverre; Rydningen, Tom Arne; Patton, Henry & Faleide, Jan Inge [Vis alle 8 forfattere av denne artikkelen] (2022). Underexplored continental shelf gateways: timing, mechanisms and role of SW Barents Sea Gateway, Norwegian Arctic. Fulltekst i vitenarkiv Vis sammendrag

  Ocean gateways connecting ocean basins are crucial for water and heat circulation, which influence global temperature, climate evolution and sediment distribution. While deep-water gateways have been a major research focus by the community, very little attention has been drawn to shallower gateways located on the continental shelves, where such circulation also takes place. In this study, we investigate the evolution of a shallow gateway in SW Barents Sea that presently connects NE Atlantic and Arctic oceans. This gateway contributes to about half of the Atlantic–Arctic water exchange, whereas the other half is occurring through the deeper Fram Strait Gateway. When and how this SW Barents Sea Gateway formed are debated and still poorly understood. Outcomes from this study will thus be relevant for regional and global models of ocean circulation. Moreover, this study will contribute to climate evolution models over longer timescale in a climate sensitive region where an Arctic amplification of warming is presently seen.

• Osmond, Johnathon; Mulrooney, Mark Joseph; Holden, Nora; Skurtveit, Elin; Faleide, Jan Inge & Braathen, Alvar (2022). Past fluid containment and present applications toward future CO2 storage in the northern Horda Platform, offshore Norway. Fulltekst i vitenarkiv
• Osmond, Johnathon L.; Mulrooney, Mark Joseph; Holden, Nora; Leon, Elias H.; Cruz, Erika H. de La & Würtzen, Camilla Louise [Vis alle 9 forfattere av denne artikkelen] (2022). Containment derisking of a potential CO2 storage hub in the Horda Platform, Norwegian North Sea. Fulltekst i vitenarkiv
• Osmond, Johnathon; Mulrooney, Mark Joseph; Holden, Nora; Skurtveit, Elin; Faleide, Jan Inge & Braathen, Alvar (2022). Distribution of faulted Mesozoic and Tertiary seals for CO2 storage in the northern Horda Platform, Norwegian North Sea. Fulltekst i vitenarkiv Vis sammendrag

  This lecture summarizes a recent case study involving the derisking of geological seals for a potential offshore CO2 storage site. In the northern Horda Platform of the northern North Sea, the structural and stratigraphic architecture of the producing Troll East hydrocarbon field is directly analogous to the Alpha CO2 storage prospect in the Smeaheia fault block just to the east of the field. Building on this observation, we have mapped the proven regional seal units of Troll East in order to extrapolate and understand their distribution throughout the northern Horda Platform. Here, we utilize our results to compare Alpha with Troll East, and discuss top and fault seal presence in the context of derisking Alpha’s CO2 storage prospectivity.

• Osmond, Johnathon; Mulrooney, Mark Joseph; Holden, Nora; Skurtveit, Elin; Faleide, Jan Inge & Braathen, Alvar (2022). Screening traps and seals for CO2 storage expansion in the northern Horda Platform, Norwegian North Sea. Fulltekst i vitenarkiv Vis sammendrag

  Evaluation and development of new and exciting CO2 storage opportunities on the Norwegian Continental Shelf is on the rise. Of note is the Aurora site located in northern Horda Platform of the Norwegian North Sea, where injection is scheduled to commence in 2024 under project Longship. While the planned injection volumes at Aurora are over 1.5 megatonnes per year, many more storage locations are required in order to meet international climate mitigation targets by 2050. Other parts of the northern Horda Platform show CO2 storage potential, but additional subsurface characterization is required. As a contribution towards this effort, I present two possible Jurassic storage complexes (Lower and Upper), where I discuss the presence of available storage aquifers, structural traps, as well as top and fault seals. Overall, our work supports the notion that the northern Horda Platform may be capable of hosting a future CO2 storage hub for northern Europe.

• Osmond, Johnathon L.; Mulrooney, Mark Joseph; Holden, Nora; Skurtveit, Elin; Faleide, Jan Inge & Braathen, Alvar (2022). Structural traps and seals for expanding CO2 storage in the northern Horda Platform, North Sea. Fulltekst i vitenarkiv Vis sammendrag

  Full-scale CO2 storage within the Norwegian Continental Shelf is scheduled to commence in 2024 at the Aurora site under project Longship and the Northern Lights JV. While tens of megatons of injected CO2 are anticipated over the coming years, many more storage locations are required in order to meet international climate mitigation targets by 2050. In the event of success at Aurora, the northern Horda Platform region could be further developed into a North Sea CO2 storage hub, but more subsurface evaluation is needed to identify prospective sites. Here, I present two possible Jurassic storage complexes (Lower and Upper), and discuss the presence of available storage aquifers, structural traps, as well as top and fault seals based on the latest 3D seismic and wellbore data. Our results indicate that both storage complex aquifers are preserved throughout the study area, and we have identified a total of 95 Lower and 64 Upper Jurassic fault-bound traps. Mapping, modeling, and formation pressure analyses suggest that top seals are sufficiently thick over the majority of identified traps, and provide vertical pressure barriers between storage aquifers. While across-fault juxtaposition seals appear to dominate the Upper Jurassic storage complexes, Lower Jurassic aquifers are often up-thrown against Middle and Upper Jurassic aquifers, posing a potential risk to CO2 containment for many Lower Jurassic footwall traps. However, I go on to show that apparent across fault pressure differentials and shale gouge ratio values >0.15 correlate at such juxtapositions, suggesting fault rock membrane seal presence. Moreover, I illustrate that aquifer self-juxtapositions are likely zones of poor fault seal within the study area. Overall, our work provides added support that the northern Horda Platform represents a promising location for CO2 storage expansion, carrying the potential to become a future storage hub for northern Europe.

• Hassan, Muhammad & Faleide, Jan Inge (2022). Crustal structure and evolution in the northern North Sea - constraints for structural restorations in Suprabasins. Fulltekst i vitenarkiv
• Osmond, Johnathon L.; Mulrooney, Mark Joseph; Holden, Nora; Leon, Elias H.; Cruz, Erika H. de La & Würtzen, Camilla Louise [Vis alle 9 forfattere av denne artikkelen] (2021). Structural traps, seals, and other geologic adventures — entertaining CO2 storage exploitation of the northern Horda Platform, North Sea. Fulltekst i vitenarkiv
• Osmond, Johnathon L.; Leon, Elias H.; Holden, Nora; Mulrooney, Mark Joseph; Skurtveit, Elin & Faleide, Jan Inge [Vis alle 7 forfattere av denne artikkelen] (2021). Geological derisking of a potential CO2 storage hub for Europe in offshore Norway. Fulltekst i vitenarkiv Vis sammendrag

  A Norwegian demonstration of the full-scale CCS value-chain is scheduled to commence in 2024. Carbon-dioxide captured from industrial sites in eastern Norway will be transported west, processed, and injected into the subsurface at the Aurora site in the northern North Sea. While Aurora represents a sizeable CO2 storage location, many more are needed in order to significantly reduce global emissions and meet climate mitigation goals. Ideally, developing additional storage sites within the vicinity of Aurora would expand on its soon-existing infrastructure, and create a potential CO2 storage hub for Norway and northern Europe. However, geological risks to CO2 containment must be identified and assessed before such a development could take place. Here, a summary of ongoing subsurface characterization work is presented in support of the storage hub concept in this region.

• Osmond, Johnathon L.; Holden, Nora; Mulrooney, Mark Joseph; Skurtveit, Elin; Faleide, Jan Inge & Braathen, Alvar (2021). Regional containment derisking for future CO2 storage in the Horda Platform, Norwegian North Sea. Fulltekst i vitenarkiv Vis sammendrag

  Full-scale CO2 storage within the Norwegian Continental Shelf is scheduled to commence in 2024 at the Aurora site under project Longship and the Northern Lights JV. While tens of megatons of injected CO2 are anticipated over the coming years, many more storage locations are required in order to meet international climate mitigation targets. In the event of success at Aurora, the remaining Horda Platform region could be further developed into a larger North Sea CO2 storage hub, but more subsurface evaluation is needed to identify prospective sites. Here, I present two possible Jurassic storage complexes (reservoirs and seals) and discuss some of my ongoing PhD work related to derisking traps, seals, and overburden geology in the region. It is hoped that these results can later be leveraged for more site-specific analyses so that new prospects can be matured to help supplement the storage volumes at Aurora site and to further develop CCS operations in the North Sea.

• Gresseth, Julie Linnea Sehested; Braathen, Alvar; Serck, Christopher Sæbø; Faleide, Jan Inge & Osmundsen, Per Terje (2021). Late Paleozoic Supradetachment Basin Configuration in SW Barents Sea – intrabasement Seismic Facies of the Fingerdjupet Subbasin. Fulltekst i vitenarkiv
• Hassaan, Muhammad; Faleide, Jan Inge; Gabrielsen, Roy Helge & Tsikalas, Filippos (2021). Pre-salt Carboniferous basin architecture, structural inheritance and segmentation in the Nordkapp Basin, Barents Sea. Fulltekst i vitenarkiv Vis sammendrag

  Reprocessed regional 2D seismic reflection profiles, 3D seismic data, available wells, and gravity and magnetic data were used to study the pre-salt rift architecture in the Nordkapp Basin, Barents Sea, and its impact on the evaporite accumulations and distribution of salt structures. The basin is subdivided into three main segments (the northeastern, central, and southwestern sub-basins) and has evolved over the complex interaction between the Timanian and Caledonian structural basement grains. Each segment is characterized by prominent magnetic anomalies related to the Timanian and Caledonian structural inheritance. The rotated magnetic lineations associated with the Caledonian structures beneath the Finnmark Platform pass through the central segment, where the Middle Allochthonous Front creates the major sub-division between the two structural grains. We suggest that the rheological properties, locations, orientations and interaction of the parts of the basement influenced by Timanian and Caledonian structural grains together with two subsequent extensional phases, have strongly influenced the shallower pre-salt rift architecture. During the late Devonian – early Carboniferous NE-SW -oriented extensional phase, the Nordkapp Basin consisted of a northern and a southern regional halfgraben separated by an elevated interbasin ridge. The hinged margins of the northern and southern regional half-grabens were restricted against the NW-SE-striking graben beneath the Veslekari Dome and Troms- Finnmark Fault Complex, respectively. The internal configuration of the regional half-grabens was affected by the NW-SE-striking master faults. During the late Carboniferous to early Permian, a second extension phase took place with a shift in stress orientation to NW -SE and influenced the two regional half-grabens. In particular, a transfer fault with the character of an interbasin transfer zone (the northern transfer zone) divided the northern regional half-graben by separating its hinged margin (incipient northeastern segment) from the deeper part (incipient central segment). At the same time, the elevated interbasin ridge acted as a southern transfer zone, separating the incipient central and southwestern segments of the Nordkapp Basin. The Thor Iversen, Polstjerna, Måsøy and Nysleppen basin border fault systems were formed during the second extensional phase and reshaped the internal configuration of the two regional half-grabens. The structural interaction between the spatially variable Timanian and Caledonian structural grains overprinted by two subsequent phases of NE-SW and NW-SE extension caused the development of seven sub-basins in the Nordkapp Basin. Internally within the sub-basins, the evolving structural elements including cross-cutting master faults and structural highs have influenced the deposition and facies of the layered evaporitic sequences and defined the location of subsequent salt structures. We suggest that the relative depth of each sub-basin, the arrangement of structural highs along with the evolving master faults and the depositional paleo-environment all controlled the thickness and facies of the syn-rift layered evaporitic sequences.

• Serck, Christopher Sæbø; Riber, Lars; Braathen, Alvar; Faleide, Jan Inge & Midtkandal, Ivar (2021). Structural development of the Utsira High - ideas and challenges. Fulltekst i vitenarkiv
• Osmond, Johnathon L.; Mulrooney, Mark Joseph; Holden, Nora; Leon, Elias H.; Cruz, Erika H. de La & Würtzen, Camilla Louise [Vis alle 9 forfattere av denne artikkelen] (2021). Containment derisking of a potential CO2 storage hub in the Horda Platform, Norwegian North Sea. Fulltekst i vitenarkiv
• Hassaan, Muhammad; Faleide, Jan Inge; Gabrielsen, Roy Helge & Tsikalas, Filippos (2021). Southeastern Norwegian Barents Sea, pre-salt and supra salt evolution of the Tiddlybanken Basin and Nordkapp Basin. Fulltekst i vitenarkiv
• Hassaan, Muhammad; Faleide, Jan Inge; Gabrielsen, Roy Helge; Tsikalas, Filippos & Grimstad, Silje (2021). Salt tectonics in the Nordkapp Basin, Barents Sea – Interplay between sediment progradation and differential loading, syn-rift layered evaporitic sequences and pre-salt rift architecture. Fulltekst i vitenarkiv Vis sammendrag

  The study utilised reprocessed regional 2D seismic reflection profiles, 3D seismic data, available wells and basin modelling to reveal the controlling factors for the supra-salt sedimentary evolution of the northeastern, central and southwestern segments of the Nordkapp Basin. The basin offers an excellent environment for the study of diverse supra-salt structural styles, including turtle structures, secondary squeezed and thrusted welds, collided mini-basins, bowl vs wedge geometries, salt wing and megaflap. The observed salt structures show different sizes, shapes, orientations and lateral extent that affect the late Permian to Cenozoic supra-salt sedimentation in the Nordkapp Basin. Some remnant topography existed in the Nordkapp Basin in the earliest Triassic related to the underlying late Devonian to early Carboniferous (NE-SW) and late Carboniferous to early Permian (NW-SE) extension structures that overprinted on the contrasting Timanian and Caledonian basement structural grains. A regional prograding system arrived from the east causing differential loading and triggering of salt movements, which in turn created significant local topography with mini-basins surrounding the growing salt structures. The resulting basin topography strongly influenced the Triassic progradational sediment routings and dictated both where the initial deposition could take place and the formation of distinct depositional fairways. The depositional fairways primarily formed by differential loading and density-driven subsidence caused by the progradational sedimentation, and have restricted the subsidence in the mini-basins outside the fairways. Once the mobile salt was depleted from the layered evaporitic sequences (LES) beneath the axial zone then the salt structure was sourced from the depocenter opposite to it. The salt was evacuated from the LES diachronically along the strike of the basin as the earliest passive diapirism occurred in the northeastern segment and then progressed to the central segment due to the direction of progradation of the approaching deltaic system. We suggest that the direction and the velocity of the prograding system arriving from the east filled the initial depositional fairways over the syn-rift LES and the pre-salt rift architecture thus defined the sedimentary depositional architecture within the Nordkapp Basin. The salt structures were slightly rejuvenated due to the reactivation of the Carboniferous structures caused by the far-field stresses propagating during late Triassic in response to the evolving Novaya Zemlya fold-and-thrust belt farther to the east. The salt was depleted from the LES by the early Cretaceous as the prograding shelf platform complex buried the salt structures. The main phase of rejuvenation of the salt structures took place during the early-middle Eocene as a result of the transpressional Eurekan/Spitsbergen orogeny farther to the northwest until the Cenozoic uplift eroded most of the post-middle Cretaceous sediments.

• Hassaan, Muhammad; Faleide, Jan Inge; Gabrielsen, Roy Helge & Tsikalas, Filippos (2021). Southeastern Norwegian Barents Sea, Tiddlybanken Basin and Nordkapp Basin evolution. Fulltekst i vitenarkiv
• Hassaan, Muhammad; Faleide, Jan Inge; Gabrielsen, Roy Helge & Tsikalas, Filippos (2021). Evaporite-influenced rift basins and salt tectonics in the southeastern Norwegian Barents Sea. Fulltekst i vitenarkiv
• Hassaan, Muhammad; Faleide, Jan Inge; Gabrielsen, Roy Helge & Tsikalas, Filippos (2021). Pre-salt and post-salt evolution of the Nordkapp Basin: valuable insights of APA acreage. Fulltekst i vitenarkiv
• Hassaan, Muhammad; Faleide, Jan Inge; Gabrielsen, Roy Helge & Tsikalas, Filippos (2021). Pre-Salt and Supra-Salt Evolution of the Nordkapp Basin, Barents Sea. Fulltekst i vitenarkiv
• Hassaan, Muhammad; Faleide, Jan Inge; Gabrielsen, Roy Helge & Tsikalas, Filippos (2021). Pre-Salt Carboniferous Basin Configuration and Supra-Salt Evolution of the Nordkapp Basin, Barents Sea: Interplay between Pre-Salt Rift Architecture and Syn-Rift Layered Evaporitic Sequences, Sediment Progradation and Differential Loading. Fulltekst i vitenarkiv Vis sammendrag

  Reprocessed regional 2D seismic reflection profiles, 3D seismic data, available wells, and gravity and magnetic data, together with basin modelling are utilised to comprehend the pre-salt Carboniferous rift architecture and supra-salt evolution of the Nordkapp Basin (study area: ~150000 sqkm). The Nordkapp Basin evolved over a basement that had been affected by complex interaction between the Timanian and Caledonian structural elements. During the late Devonian-early Carboniferous NE-SW-oriented extension, the Nordkapp Basin consisted of a northern and a southern regional half-graben separated by an elevated interbasin ridge. During the late Carboniferous-early Permian, a second extension phase took place with a shift in stress orientation to NW-SE that influenced the two regional half-grabens and caused the development of seven sub-basins separated by interbasin transfer zones in the Nordkapp Basin. The relative depth of each sub-basin, the arrangement of structural highs along with evolving master faults and depositional paleo-environment all controlled the thickness and facies of syn-rift layered evaporitic sequences (LES). Some remnant topography existed in the Nordkapp Basin in the earliest Triassic, when a regional prograding system arrived from the east causing differential loading and triggering the salt movements, which in turn created significant local topography with mini-basins surrounding the growing salt structures. The resulting composite basin topography strongly influenced the Triassic progradational sediment routings and dictated both where the initial deposition could take place and the formation of distinct depositional fairways. Basin modelling and structural restoration have revealed that once the mobile salt depleted from the syn-rift LES beneath the axial zone then the salt structure was sourced from depocenter opposite to it. The salt structures were slightly rejuvenated due to the reactivation of the Carboniferous structures caused by the far-field stresses propagating during late Triassic in response to the evolving Novaya Zemlya fold-and-thrust belt farther to the east. The salt was depleted from the synrift LES by the early Cretaceous as the prograding shelf platform complex buried the salt structures. The main phase of rejuvenation of the salt structures took place during the early-middle Eocene as a result of the transpressional Eurekan/Spitsbergen orogeny farther to the northwest until the Cenozoic uplift eroded most of the post-middle Cretaceous sediments. The spatially diverse salt structures affected the late Permian to Cenozoic supra-salt sedimentary strata in the Nordkapp Basin which offers an excellent environment to study the distinct supra-salt structural styles, including turtle structures, secondary and thrusted welds, bowl vs wedge geometries, collided and secondary mini-basins, salt wings and megaflaps.

• Osmond, Johnathon L.; Mulrooney, Mark Joseph; Holden, Nora; Skurtveit, Elin; Faleide, Jan Inge & Braathen, Alvar (2021). Top and lateral seal characterizations for CCS in Jurassic saline aquifers, Horda Platform, Northern North Sea. Fulltekst i vitenarkiv Vis sammendrag

  Capture of industrially sourced CO₂ and transport to the Aurora subsurface storage site in the northern North Sea are approved to commence in 2024 under the direction of the Longship and Northern Lights projects. Results from well 31/5-7 drilled in early 2020 within exploitation license EL001 confirmed suitable parameters at Aurora (e.g., porosity, injectivity, etc.). While the geology of the site proves promising for CCS, it remains imperative to mature additional locations in order to meet current climate mitigation targets and establish the Horda Platform as a European storage hub. Planned injection and containment at Aurora will be hosted by the Lower Jurassic Dunlin Gp stratigraphic storage complex (storage aquifer and seals), however, the Upper Jurassic Viking Gp represents an additional storage complex. Moreover, Aurora is located in the western-most of three large, basement-rooted fault blocks, each showing storage potential. Hundreds of thick- and thin-skinned faults create two- and three-way structural traps for both storage complexes in all three fault blocks. Some Viking Gp traps contain hydrocarbons (e.g., Troll field), providing direct analogs, but should be avoided for CO₂ storage until the end of their production life around 2050. Nevertheless, the remaining structural traps currently make the most attractive storage prospects, as they can focus injected CO₂ in a predicable fashion, particularly during the early stages of the sequestration process before other trapping mechanisms take over (e.g., residual trapping). As both top and lateral seals must completely envelop the storage aquifer, understanding the distribution and nature of the seals is critical for predicting subsurface CO₂ containment. In order to provide insight towards additional CCS potential in the Horda Platform, we present a summation of top and lateral seal mapping, modeling, and observations for the Dunlin and Viking Gp storage complexes in the three major fault blocks. For the Dunlin Gp storage complex, interpretation of its top seal distribution from 3D seismic and wellbore data confirm seal presence in all three fault blocks, including that of the Aurora site. The majority of small thin-skinned faults at the Jurassic stratigraphic level and create aquifer juxtapositions against the top seal, while larger thick-skinned faults must provide membrane seals along the largest closures. In these latter cases, the Dunlin Gp sandstone aquifer is up-thrown and juxtaposed against the overlying Viking Gp sandstone aquifer, but shale gouge ratio analysis and regional aquifer pressures suggest favorable membrane fault seal potential. Top seal formations above the Viking Gp aquifer are determined to be present throughout the Horda Platform, but only the eastern-most fault block is currently prospective for CO₂ storage, given the high risk of contaminating producing fields in adjacent fault blocks. Fault seals in this case appear to be juxtaposition-controlled, even for thick-skinned faults, which are analogous to Troll East. Considering the availability of structural traps for expanding storage activities in the Horda Platform, our work infers that the presence top and lateral seals is probable for both the Dunlin and Viking Gp storage complexes.

• Würtzen, Camilla Louise; Osmond, Johnathon L.; Faleide, Jan Inge; Nystuen, Johan Petter; Anell, Ingrid Margareta & Midtkandal, Ivar (2021). Syn- to post rift alluvial basin fill: seismic stratigraphic analysis of Permian-Triassic deposition in the Horda Platform. Fulltekst i vitenarkiv
• Osmond, Johnathon L.; Holden, Nora; Leon, Elias H.; Mulrooney, Mark Joseph; Skurtveit, Elin & Faleide, Jan Inge [Vis alle 7 forfattere av denne artikkelen] (2021). Top and lateral seal characterizations for CO2 storage in Jurassic saline aquifers of the Horda Platform. Fulltekst i vitenarkiv
• Hassaan, Muhammad; Faleide, Jan Inge; Gabrielsen, Roy Helge & Tsikalas, Filippos (2021). Evaporite-influenced rift basins and salt tectonics in the southeastern Norwegian Barents Sea. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  The doctoral thesis is a collection of four published journal papers, which investigate the influence of the basement inheritance on the pre-salt basin configuration and its effects on the accumulation of the layered evaporite sequence, salt tectonics and post-salt sedimentation in evaporite-influenced rift basins. The thesis has shown that rheological properties, locations, orientation and interaction of inherited structures created zones of weakness that influenced the development of complex pre-salt basin architecture along with subsequent regional extensional phases. Consequently, the syn-rift to post-rift processes within discrete accommodation space of varying depth and depositional paleo-environment, have influenced the thickness and facies (mobile to non-mobile) of the layered evaporite sequence. The study highlights that the regional extension and prograding sediment influx direction, the sediment transport velocity and the sediment thickness influenced the dynamics of the early to late passive diapirism, the salt expulsion and the depletion, together with the layered evaporite thickness and facies that were affected by the pre-salt rift architecture. The salt structures and evaporite-cored domes were rejuvenated due to far-field contractional stresses and eventually uplift eroded the successions over their crests.

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