Sverre Planke

• Senger, Kim; Ammerlaan, Fenna; Betlem, Peter; Gaina, Carmen; Galland, Olivier & Grundvåg, Sten-Andreas [Show all 21 contributors for this article] (2026). A Field Guide to the High Arctic Large Igneous Province in and Around Isfjorden, Svalbard. Tektonika. 3(2), p. 176–216. doi: https:/tektonika.online/index.php/home/article/view/124/197. Full text in Research Archive Show summary

  The High Arctic Large Igneous Province (HALIP) is a major tectono-magmatic element that affected large parts of the Arctic during the Cretaceous (magmatism occurred from 126 to 78 million years ago [Ma]). In Svalbard, HALIP intrusive and extrusive rocks are grouped and classified as the Diabasodden Suite. Sills and dykes are present throughout Svalbard, emplaced in units stratigraphically ranging from crystalline basement to Jurassic-Cretaceous siliciclastics. Time-equivalent lava flows are exposed on Kong Karls Land in eastern Svalbard. In this contribution, we firstly define and introduce major features of the circum-Arctic HALIP. Secondly, we zoom into Svalbard where we document and summarize the attributes of HALIP outcrops (i.e., the Diabasodden Suite) located in and around Isfjorden, the most accessible location that is reachable on day trips using boats from Longyearbyen. For each of the 15 sites we focus on specific aspects of HALIP characterization, including geochronology, geochemistry and geometry of volcanic and intrusive rocks. We complement field descriptions of the sites with digital geoscientific data, including digital outcrop models and photospheres. Finally, we synthesize the Isfjorden study area in the context of data and knowledge gaps for the HALIP in general. We hope that this contribution will stimulate further HALIP research in Isfjorden and beyond.

• Telmon, Maria; Grundvåg, Sten-Andreas; Senger, Kim; Planke, Sverre; Horota, Rafael Kenji & Betlem, Peter [Show all 12 contributors for this article] (2026). Miocene flood basalts in NW Spitsbergen: Emplacement environment and Arctic paleoclimate context. Journal of Volcanology and Geothermal Research. ISSN 0377-0273. 479. doi: 10.1016/j.jvolgeores.2026.108724. Full text in Research Archive Show summary

  Large parts of the Arctic, including Svalbard, have experienced recurrent episodes of uplift and erosion over the last 15–20 million years, coinciding with localized magmatism and seafloor spreading. This has left sparse onshore stratigraphic records of the Miocene period, limiting our understanding of the tectono-sedimentary and paleo-landscape evolution across this vast region. The volcanic Seidfjellet Formation in northwestern Spitsbergen thus provides a rare e onshore Miocene record. To determine emplacement mechanisms, volcanic architecture, and the pre-volcanic paleoenvironment, we combined detailed field-based facies analysis with digital outcrop models, thin-section petrography, and palynology. We document 10–20 basaltic lava flows, totaling ~400 m in cumulative thickness, now exposed at 600–1350 m elevation. The lava sequence rests on a gently undulating Devonian peneplane that locally is incised by several-hundred-meters-wide, up to 150-m-deep depressions interpreted as paleo-valleys. These valleys likely formed by stream rejuvenation associated with Miocene peneplane uplift. At valley bases we report previously unrecognized pockets of unconsolidated sediment, evidence of pre-volcanic sedimentation. Valley margins are locally draped by volcaniclastic deposits that contain in-situ charcoal-lined tree molds, indicating forested margins before eruption. The main valley fills are hyaloclastite deposits up to 150 m thick, arranged in steeply dipping forests that record southward progradation of a lava-fed delta after base-level rise and drowning of the valleys. Palynological data indicate a conifer-dominated wetland prior to lava emplacement, while the dinocyst assemblages appear partly reworked and are consistent with a Late Oligocene–Early Miocene signal but more likely reflect a Late Miocene age. This study provides the first systematic description of the Seidfjellet Formation volcanic facies and architecture, constrains its spatial extent, and, through its pre-volcanic sedimentary records, offers new paleoenvironmental reconstructions. Finally, our findings highlight the interplay between magmatism and uplift during Svalbard’s Miocene evolution

• Rosenqvist, Marija Plahter; Dunkel, Kristina; Nogueira, Liebert Parreiras; Planke, Sverre; Polteau, Stephane & Ardit, M. [Show all 8 contributors for this article] (2026). Natural CO<inf>2</inf>sequestration: mechanisms and conditions of carbonate precipitation in basalt. Geochimica et Cosmochimica Acta. ISSN 0016-7037. 427, p. 381–402. doi: 10.1016/j.gca.2026.07.013. Full text in Research Archive
• Minakov, Alexander; Kämpf, Horst; Varılsüha, Deniz; Senger, Kim; Smirnov, Maxim & Niedermann, Samuel [Show all 16 contributors for this article] (2026). Structure and Origin of an Active Hydrothermal System in NW Svalbard: A Combined Magnetotelluric and Gas‐Water Isotope Study. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 131(7). doi: 10.1029/2025jb033374. Full text in Research Archive Show summary

  The Woodfjorden area in northwestern Svalbard hosts the world's northernmost onshore thermal springs, extinct Quaternary volcanoes (the Bockfjorden Volcanic Complex), late Miocene lava flows (the Seidfjellet Formation) that overlie a Devonian sedimentary basin, and a long‐lived regional fault zone. To contribute to a better understanding of subsurface fluid flow in this volcanic region, we conducted a 3D magnetotelluric (MT) survey at 12 sites, combined with water and gas sampling at the thermal spring clusters (Trollkjeldene and Jotunkjeldene). While the MT survey has a limited aperture due to the remoteness of the region and complex logistics, the identified structural features put several constraints on the evolution of this poorly studied hydrothermal system. The electrically conductive zones (1–10 m), under Trollkjeldene and the Halvdanpiggen volcanic center, are interpreted as signatures of deep hydrothermal fluids or mineralized zones; the resistive anomalies (1–10 km) at 1–4 km depth under the Sverrefjllet volcano indicate buried magmatic or basement rocks. Stable isotope data indicate both meteoric and crustal components for thermal waters. Carbon and noble gas isotope ratios support a mixed gas source involving crustal, atmospheric, and mantle components. Helium isotope ratios suggest a mantle‐derived fraction of 6%–8%. These findings suggest extinct magmatic activity and ongoing hydrothermal circulation, likely prolonged due to fluid compartmentalization at depth by low‐permeability magmatic or metamorphic rocks.

• Tegner, C.; Guo, P.; Chatterjee, S.; Lambart, S.; Jones, Morgan Thomas & Planke, Sverre [Show all 27 contributors for this article] (2026). A whole rock geochemical dataset for magmatic rocks drilled on the mid-Norwegian margin. Scientific Data. 13. doi: 10.1038/s41597-026-07073-x. Full text in Research Archive Show summary

  The mid-Norwegian margin is one of the best studied volcanic rifted margins on Earth. Geophysical investigations have demonstrated the presence of well-developed inner and outer Seaward Dipping Reflectors (SDRs), landward flows, lava deltas, marginal highs, volcanic centers, ash layers, and sill complexes. These features have been proven to consist of magmatic rocks through the international Deep Sea Drilling Program (DSDP Leg 38, 1974), Ocean Drilling Program (ODP Leg 104, 1985), International Ocean Discovery Program (IODP Expedition 396, 2021), and commercial drilling. A total of fifteen drill cores penetrated magmatic rocks that formed between 57 and 50 million years ago (Ma). Here we provide (i) new ( n =  224) major and trace element compositions obtained by X-ray fluorescence (XRF), inductively-coupled plasma mass spectrometry (ICP-MS), and inductively-coupled optical emission spectrometry (ICP–OES) on whole rock powders of magmatic rocks for IODP Exp. 396 ( n  = 119), ODP Exp. 104 ( n =  79), DSDP Exp. 38 ( n  = 24); and (ii) a compilation of all new and published data for magmatic rocks in the fifteen drill cores ( n  = 563). Portable X-ray fluorescence (pXRF) data ( n  = 381) for the IODP Exp. 396 cores are also reported. These datasets provide a resource for examining the origin of magmatism associated with continental breakup and rifted margin formation, particularly the formation of excess magmatism compared to normal mid-oceanic spreading ridges, mantle-crust interaction, and the linkage of magmatism to global hyperthermal events on Earth’s surface.

• Morris, Richard Ashley; Lambart, Sarah; Zarikian, Carlos A. Alvarez; Millett, John; Jones, Morgan Thomas & Planke, Sverre [Show all 16 contributors for this article] (2026). Recommendations for using core X-ray fluorescence data on basaltic rock as a tool to assess compositional variability. Scientific Drilling. ISSN 1816-8957. 35, p. 21–37. doi: 10.5194/sd-35-21-2026. Full text in Research Archive Show summary

  Portable and core-scanning X-ray fluorescence (XRF) instruments have become increasingly utilized in making rapid, non-destructive chemical characterizations with high spatial resolution on a range of materials. Since basaltic cores are often highly fractured and uneven, portable XRF (pXRF) is preferred to conduct discrete chemical analyses. However, in this case, the user must select the location for each analysis, which can lead to biased datasets. Alternatively, XRF core-scanning (XRF-cs) instruments take a series of measurements along a section of core, increasing the number of analyses and, therefore, eliminating some of the bias introduced by discrete analyses conducted with a pXRF. The XRF-cs does, however, still require a flat sampling surface along the core that does not include void spaces, making rigid, vesicular, and often cracked basalts suboptimal targets. We collected 797 XRF-cs measurements on three basaltic cores collected during the International Ocean Discovery Program Expedition 396 to evaluate how effectively an XRF core scanner can build large, chemically representative datasets. We developed a method for filtering XRF-cs measurements and calibrated the data using discrete calibrated pXRF analyses and compared the XRF-cs data to pXRF and conventional bulk-rock data using various immobile (e.g., Al, Ti, Zr, Ni, Mn, Zn) and mobile (e.g., K, Ca, Sr) elements. The comparison between datasets shows that (1) the XRF-cs data reproduce trends observed by pXRF and conventional bulk-rock data at both the regional scale and the core scale, and (2) in some cases, the higher spatial resolution of the XRF-cs data reveals geochemical variations that are otherwise obscured using discrete analyses. The workflow outlined by this study can be used to select samples for future studies by efficiently providing reliable geochemical data for characterizing new and legacy hard-rock cores.

• Johannesen, Rakul Maria Ingunardóttir; Galland, Olivier; Kjøll, Hans Jørgen; Ólavsdóttir, Jana; Eidesgaard, Óluva & Planke, Sverre (2026). Impact of fractures on basaltic reservoirs - Field characterisation of fracture distribution in lava flows, Faroe Islands. International Journal of Greenhouse Gas Control. ISSN 1750-5836. 151. doi: 10.1016/j.ijggc.2026.104620. Full text in Research Archive
• Zastrozhnov, Dmitrii; Zastrozhnov, Dmitry; Millett, John; Millett, John M.; Planke, Sverre & Polteau, Stéphane [Show all 18 contributors for this article] (2026). Polymetallic nodules offshore NE Greenland: links to Fram Strait opening and local hydrothermal activity. Sedimentary Geology. ISSN 0037-0738. 495, p. 107033–107033. doi: 10.1016/j.sedgeo.2026.107033. Full text in Research Archive Show summary

  This study presents the first documentation and analysis of polymetallic Fe–Mn seafloor nodules from offshore Northeast Greenland. Samples were collected from three sites by dredging and gravity coring along the slopes of both the outer and transform margin highs. The morphology, petrography, and whole-rock geochemistry of twenty-four nodules were determined. 10Be/9Be and (U–Th)/He dating were undertaken for representative samples to constrain the time of formation. Two nodule groups were identified in all studied sampling sites. Group 1 (n = 19) are light banded, primarily hydrogenetic nodules with notable enrichments in Mn and Fe, as well as several trace elements including rare earth elements (REE), V, Co, and Y. They have geochemical and textural similarities to Fe–Mn deposits from the Arctic Basin. 10Be/9Be age estimates suggest that growth initiated around 13,5 Ma, shortly after the opening of the Fram Strait, which influence deep-water circulation and inflow of nutrient-rich Arctic waters onto the NE Greenland shelf. Group 2 nodules (n = 5) are dense with high Fe (up to 64 wt% Fe2O3), low Mn content and little to no enrichment in trace elements and REEs. They are interpreted as hydrothermal in origin, with preliminary (U–Th)/He ages suggesting Quaternary formation under weak, diffuse fluid circulation in near-bottom environments of uncertain source. This study expands our understanding of seafloor mineralization in the Arctic–North Atlantic gateway, revealing that on the NE Greenland shelf this process reflects a long-term interplay between tectonic evolution, ocean circulation, and fluid-driven alteration.

• Cunningham, Emily H.; Lambart, Sarah; Guo, Pengyuan; Chatterjee, Sayantani; Tegner, Christian Maughan & Hartley, Autumn [Show all 25 contributors for this article] (2026). Evolution of the Source Mineralogy and Lithospheric Controls on Magmatism During the Northeast Atlantic Continental Breakup. Geochemistry Geophysics Geosystems. 27(2). doi: 10.1029/2025gc012556. Full text in Research Archive Show summary

  The mid‐Norwegian Margin, part of the North Atlantic Igneous Province (NAIP), is a well‐studied volcanic rifted margin formed during the breakup between Greenland and Eurasia ∼56 Ma, with the largest accumulation of magmatic material hosted by the Vøring Margin section. Despite extensive study in the area, the main controls on magmatic productivity during continental breakup remain debated. To constrain the drivers of breakup magmatism, we developed an inverse Monte Carlo statistical melting model that infers source mineralogy from basalt chemistry. When applied to basalts recently recovered on the Vøring Margin, our results reveal a clear shift in source mineralogy during rifting, with peak magmatism coinciding with clinopyroxene enrichment, despite mantle potential temperatures likely being capped below 1500°C. We also establish that, while the proto‐Iceland mantle plume played a role during the emplacement of the NAIP, the main driver for the continental breakup magmatism is lithospheric thinning as a consequence of continent breakup. This study provides new insights into the magmatic and geodynamic evolution of the mid‐Norwegian Margin, emphasizing the role of lithospheric refertilization in driving breakup magmatism.

• Polteau, Stéphane; Smalley, P. Craig; Devegowda, Vani N.; Johansen, Ingar; Millett, John & Rosenqvist, Marija Plahter [Show all 8 contributors for this article] (2026). Well-connected basalt sequences as potential reservoirs for large-scale carbon sequestration revealed by strontium isotopes. Communications Earth & Environment. 7(1). doi: 10.1038/s43247-025-03020-7. Full text in Research Archive Show summary

  Abstract Permanent storage of gigatons of carbon in basalt requires thick, uncompartmentalized sequences that allow lateral dissipation of CO 2 away from injection sites. Here we assess the presence of flow barriers by evaluating the variations in 87 Sr/ 86 Sr patterns in pore water, a method used extensively in sedimentary successions. Present-day pore water 87 Sr/ 86 Sr was measured from residual salts in core samples, while past water compositions were reconstructed from carbonate cements of different ages. We reveal smooth and uninterrupted trends in strontium isotopes through a 100 m thick basalt section indicating a common fluid reservoir unaffected by low-permeability massive lava flow interiors. The data further indicate that unconsolidated overburden sediments act as a good seal preventing seawater to mix with in situ pore water, and buoyant supercritical CO 2 to leak. Finally, basaltic sequences form viable targets for CO 2 storage and suggests that fractures may bypass low-permeability units to create a well-connected reservoir system.

• Betlem, Peter; Rosenqvist, Marija Plahter; Millett, John; Griffiths, Luke; Filina, Irina & Park, Joonsang [Show all 9 contributors for this article] (2025). Fluid flow behaviour in vesicular basalt samples from the Skoll High, Vøring Margin. Geomechanics and Geophysics for Geo-Energy and Geo-Resources. ISSN 2363-8419. 12(1). doi: 10.1007/s40948-025-01080-9. Full text in Research Archive Show summary

  Abstract This study presents the fluid flow testing results of 32 lava flow samples recovered from IODP Sites U1571/U1572 (145–315 mbsf) on the Skoll High, Vøring Margin. Few past studies have investigated the mid-Norwegian margin’s basalt reservoir and flow properties. Even fewer implement subsurface-like conditions to explore in-situ fluid flow and the possible response to changing pore fluids during injection. These aspects are critical for large-scale carbon sequestration. In this study, hydraulic properties including porosity and permeability were measured at ambient conditions for all samples along with multi-stress, multi-fluid core flooding experiments on a representative sample enclosed in an X-ray µCT scanner. Petrographic observations reveal varying degrees of alteration with secondary clays, including smectite, commonly lining pores and vesicles. He-porosities (4.2–45.6%) fall mostly below the theoretical percolation threshold of ~ 30% for randomly distributed spherical pores. Klinkenberg-corrected nitrogen-gas permeability (0.0038–361.9 mD) shows weak correlation to porosity and no apparent depth dependence. Further, brine permeability is four orders of magnitude lower than gas permeability, with no notable flow reduction during injection of CO 2 . Rather than being stress-dependent, we argue that brine-induced swelling significantly reduced the accessibility of microstructural elements to fluids. The findings urge caution when using literature-reported, ambient gas measurements for basalts with similar levels of alteration as they may not accurately reflect in-situ fluid flow properties. Low matrix permeability of the moderately to highly altered vesicular basalts and prevalence of swelling clays may, without major contributions from fractures, limit the injectivity potential into the basaltic lava flows on the Skoll High, Vøring Margin.

• Jones, Morgan Thomas; Augland, Lars Eivind; Ovtcharova, Maria; Stokke, Ella Wulfsberg; Ganerød, Morgan & Planke, Sverre (2025). New constraints on the absolute age and duration of the Paleocene – Eocene Thermal Maximum (PETM) from ash layer +19 in Denmark. Earth and Planetary Science Letters. ISSN 0012-821X. 671. doi: 10.1016/j.epsl.2025.119643. Full text in Research Archive Show summary

  Precise age constraints for the onset and duration of the Paleocene–Eocene Thermal Maximum (PETM) are essential for understanding the mechanisms that triggered and sustained this major climate perturbation. However, establishing a precise PETM geochronology is complicated by uncertainties in orbital tuning and a current lack of precise radiometrically dated marker horizons. An early Eocene rhyolitic ash layer named +19 is a promising marker horizon due to its distinct geochemistry, its occurrence in key offshore archives, and well-preserved outcrops in Denmark such as Stolleklint, where it conformably overlies PETM strata. We present a new high-precision U-Pb zircon age of 55.331 ± 0.053/(0.060)/[0.080] Ma for ash +19, supported by a new Ar-Ar age of 55.424 ± 0.115/(0.116)/[0.320] Ma within uncertainty. The ash +19 U-Pb age enables direct comparison with ash SB01–1 in Svalbard that was erupted during the PETM carbon isotope excursion (CIE), yielding a 454 ± 90 kyr interval between the two layers. This provides a robust geochronological link from the PETM to ash +19 that is independent of stratigraphic interpretations. Using end-member PETM durations (94–170 kyr), we estimate the time between the PETM onset and ash +19 as 528–604 ± 102 kyr, which is significantly shorter than the 862 ± 20 kyr interval derived from astronomical tuning. Adopting the longer helium isotope-based PETM duration yields an onset age of 55.935 ± 0.102 Ma, with a CIE recovery end at 55.700 Ma. A shorter PETM duration requires a younger PETM onset age. The positive ash series in Denmark, correlating with the offshore Balder Formation, is now constrained to a 250 kyr interval between 55.367 and 55.117 ± 0.080 Ma. This refined age model provides a robust framework for testing and improving early Eocene astronomical time scales.

• Tiller, B. K.; Batchelor, C. L.; Bellwald, Benjamin; Manton, B.; Winter, K. & Ross, N. [Show all 7 contributors for this article] (2025). Stad Slide: Preconditioning and failure of one of the world's largest megaslides. Journal of Quaternary Science. ISSN 0267-8179. 40(8), p. 1392–1406. doi: 10.1002/jqs.70022. Full text in Research Archive Show summary

  ABSTRACT Submarine landslides can generate tsunamis and pose risks to underwater infrastructure, but a lack of direct observations of such slides hinders our understanding of their development and hazard potential. Studying the morphology of past slides can offer insights into their preconditioning and failure. Here, new high‐quality 2D and 3D seismic data were used to determine, for the first time, the extent and morphology of the Stad Slide (~0.4 Ma) on the northeast Atlantic margin. With a volume of ~4300 km 3 and a maximum thickness of ~360 m, we reveal that this slide is the largest by volume on the proximal North Sea Fan and amongst the largest known megaslides globally. Its large volume was likely facilitated by retrogressive development along layers of glacimarine and contouritic sediment. The broad timing of the Stad Slide aligns with enhanced glacial sedimentation in this region, which is likely to have preconditioned failure by increasing overpressure in underlying sediments. The slide headwalls are infilled by an ~200 m‐thick contourite drift that may have formed the weak layer for subsequent sliding on the North Sea Fan.

• Knies, Jochen Manfred; Killops, Stephen; Brekke, Trond; Grøsfjeld, Kari; Sliwinska, Kasia K. & Planke, Sverre [Show all 13 contributors for this article] (2025). A prolific Tertiary source rock of terrestrial origin in the eastern Nordic Seas. Marine and Petroleum Geology. ISSN 0264-8172. 183. doi: 10.1016/j.marpetgeo.2025.107637. Full text in Research Archive Show summary

  This study evaluates the source rock potential, organic matter input, and depositional environments of Miocene-aged sediments in the eastern Nordic Seas. It focuses on ODP/IODP Sites 909, 985, and U1572, two exploration wells (7316/5-1 and 6608/10-1), and oil seeps offshore western Svalbard. Integrated marine palynological, biomarker, and geochemical analyses indicate a mainly Early to Middle Miocene age and a mixed terrestrial-marine origin of the sedimentary organic matter and associated oil seeps. Angiosperm-derived biomarkers, especially triterpenoids like oleananes and oleanenes, are abundant and help link seeping oils to deltaic terrestrial sources. Depositional settings ranged from oxic in the Fram Strait (Hole 909C) to dysoxic or anoxic in southern Sites (Holes 985A and U1572B), influenced by the semi-enclosed Nordic Seas. Geochemical indicators such as sulfur content, TOC/S ratios, and Pr/Ph values reflect variations in bottom water oxygenation and sediment conditions. Terrestrial organic input is linked to Miocene deltaic systems, likely formed by tectonic uplift in East Greenland, the Barents Sea, and central Norway. Basin modeling in the southwestern Barents Sea, using seismic and well data, shows that Miocene source rocks have reached maturity levels sufficient for hydrocarbon generation, especially beneath thick Plio-Pleistocene glacial overburden. The presence of oleanene and oleanane in both boreholes and oil seeps supports the conclusion that these Miocene source rocks are regionally widespread and part of an active petroleum system

• Jakobsen, Frank Werner; Winsborrow, Monica; Nielsen, Tove; Laberg, Jan Sverre; Plaza-Faverola, Andreia & Böttner, Christoph [Show all 9 contributors for this article] (2025). Continental shelf glaciations off Northeast Greenland since the Late Miocene. Climate of the Past. ISSN 1814-9324. 21(11), p. 2441–2464. doi: 10.5194/cp-21-2441-2025. Full text in Research Archive Show summary

  Amplified Arctic warming is triggering dramatic changes to the Greenland Ice Sheet (GrIS). Studying past warm periods can provide process insights valuable to predictions of future ice sheet response. Miocene (23.03–5.33 Ma) and Pliocene (5.33–2.58 Ma) global climatic records include periods of warmer than present temperatures thought to represent analogues to near-future scenarios. Despite this, the details of the long-term glacial history of the eastern and northeastern sectors of Greenland are still largely unresolved. Here, we use seismic reflection and borehole data to describe the late Cenozoic glacial architectural development of the Northeast Greenland continental margin and thereby reconstruct long-term ice sheet evolution. We identify three key unconformable seismic surfaces that define three mega units of predominantly glacial origin. Two of the surfaces are for the first time correlated across the entire outer Northeast Greenland margin and tied to both Ocean Drilling Program Site 909 and Site 913. We show that the Late Miocene onset of shelf progradation occurs around 6.4 Ma, marking the first recorded advance of grounded ice masses across the NE Greenland shelf, forming depocentres (trough mouth fans) beyond the palaeo-shelf edge. Subsequently during the Late Miocene and Early Pliocene, the GrIS expands multiple times across the shelf, extending the continental shelf seawards. Based on the development of more extensive and thicker depocentres along the entire outer shelf and upper slope, we suggest an intensification of shelf glaciations sometime after ∼ 4.1 Ma, possibly coinciding with the intensification of the Northern Hemisphere glaciations (3.6–2.7 Ma).

• Smyrak-Sikora, Aleksandra; Betlem, Peter; Engelschiøn, Victoria Sjøholt; Foster, William J.; Grundvåg, Sten-Andreas & Jelby, Mads Engholm [Show all 26 contributors for this article] (2025). Phanerozoic paleoenvironmental and paleoclimatic evolution in Svalbard. Climate of the Past. ISSN 1814-9324. 21(11), p. 2133–2187. doi: 10.5194/cp-21-2133-2025. Full text in Research Archive Show summary

  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.

• Böttner, Christoph; Jakobsen, Frank Werner; Nielsen, Tove; Winsborrow, Monica; Polteau, Stephane & Mazzini, Adriano [Show all 14 contributors for this article] (2025). Natural hydrocarbon seepage at the Northeast Greenland continental shelf. Communications Earth & Environment. 6. doi: 10.1038/s43247-025-02932-8. Full text in Research Archive Show summary

  In the Arctic, substantial amounts of methane are stored in marine sediments. Yet, the distribution and stability of methane reservoirs is poorly understood, especially offshore Greenland. As Arctic warming accelerates, understanding natural methane seepage is crucial for assessing its role in the carbon cycle and climate impact. Here, we present a unique interdisciplinary geoscientific data set that spans the ice-covered Northeast Greenland shelf and captures entire fluid flow systems from source to sink. Our data documents widespread natural seepage of oil and gas from the seafloor through the water column, locally reaching the sea surface. The released hydrocarbons are sourced from deep petroleum systems and primarily migrate along permeable beds towards the seafloor. Glacial erosion during the Quaternary has effectively removed the sealing units, creating geologic windows that allow widespread natural seepage. Our first-order estimates suggest that minimum 677–1460 Mt of thermogenic gas ( ~ 0.5–1.1 Gt of carbon) has been released into the ocean since grounded ice retreated from the shelf around ~15 ka BP. These findings provide new insight into the impact of active natural seepage in a rapidly changing climate and have substantial implications for the Arctic Ocean’s carbon cycle and marine ecosystems.

• Binde, Cornelia Mentzoni; Manton, B.; Plaza-Faverola, Andreia; Bünz, Stefan & Planke, S. (2025). Seismic Characteristics and Morphology of an Igneous Intrusion in the Vøring Basin, Offshore Norway: New Insights on the Lateral Evolution of Elongated Intrusions. Geochemistry Geophysics Geosystems. 26(10). doi: 10.1029/2025gc012429. Full text in Research Archive Show summary

  Igneous sill intrusions are common features in volcanic basins worldwide, constituting important components of basin‐scale magma plumbing systems. While sills exhibiting simple geometries, such as saucer‐shaped sills, are commonly linked to distinct mechanical processes, emplacement mechanisms for sills exhibiting more complex geometries are debated. To better understand the emplacement of complex sills, this study aims to constrain the formation mechanisms associated with the Infinity Sill, a 237 km 2 elongated sill located in the SW Vøring Basin. Detailed seismic interpretation and attribute analysis of an industry‐standard 15,000 km 2 3D seismic data set reveal that the 36 km long and 4–8 km wide Infinity Sill intruded mud‐dominated Late Cretaceous strata. The thickness of the sill has been estimated to be dominantly 50–150 m, with a volume of ∼20 km 3 (ranging between 7.9 and 25.5 km 3 ). The shape of the sill and geometry of the sill elements suggest that the sill propagated as a large, magma‐filled fracture exploiting a pre‐existing polygonal fault network during propagation. The sill originated at a source in the SW, and the asymmetric propagation away from the source facilitated a 36 km lateral elongation of the sill, contrasting along‐axis dike models for elongated intrusion geometries. Local deformation around the sill initially facilitated continuous transgression, but with increasing sill length, forced folding of the overburden triggered abrupt transgression of the sill margins, resulting in a lateral change in geometry. The Infinity Sill, with its distinct geometrical features and changing cross‐sectional geometry, demonstrates that complex sill geometries are formed by a combination of emplacement mechanisms.

• Beaty, Brian; Foster, William J.; Zuchuat, Valentin; Moller, Spencer R.; Buchwald, Stella Z. & Brooks, Hannah [Show all 13 contributors for this article] (2025). Bioturbation Shapes Marine Biogeochemical Cycling Following the End‐Permian Mass Extinction in Northern Pangea. Geobiology. ISSN 1472-4677. 23(5). doi: 10.1111/gbi.70032. Full text in Research Archive Show summary

  During the end‐Permian mass extinction, a global decline in seafloor sediment mixing and burrowing (bioturbation) provides critical evidence for the collapse of marine ecosystems, likely triggered by rapid ocean warming and deoxygenation. However, the decline and subsequent recovery of bioturbation after the extinction event may not only have been a symptom of environmental change but also a driver, influencing nutrient exchange and reductant burial across the sediment–water interface and thus water column oxygen availability and seafloor habitability more broadly. Here we test this hypothesis through combined analyses of bioturbation and sedimentary geochemistry, focusing on marine siliciclastic records of the Permian–Triassic transition from Svalbard. We find that total organic carbon, total sulfur, and organic phosphorus decrease with increasing bioturbation intensity, whereas inorganic reactive phosphorus phases (authigenic and iron oxide‐bound phosphorus) increase. These differences are most strongly associated with biodiffusion (particle mixing) rather than bioirrigation (solute exchange). Our findings suggest that bioturbation primarily influenced sediment chemistry by enhancing organic matter oxidation, in contrast to some modern settings where downward mixing may promote organic matter preservation within the anoxic portion of seafloor sediments. The early return of shallow‐tier bioturbators in this region < 200 kyr after the extinction event likely promoted a rapid restoration of efficient carbon and sulfur cycling within benthic ecosystems. In contrast, efficient phosphorus burial via sink‐switching may not have resumed until deeper‐tier bioturbators achieved pre‐extinction levels of sediment mixing > 1 Myr after the mass extinction.

• Kjøll, Hans Jørgen; Midtkandal, Ivar; Manton, Ben & Planke, Sverre (2025). Seismic Geomorphology of an Early Eocene Canyon‐Channel‐Lobe System North of Shetland. Basin Research. ISSN 0950-091X. 37(3), p. 78–105. doi: 10.1111/bre.70031. Full text in Research Archive Show summary

  Submarine canyon and channel systems are the primary paths for sediment transport from platforms to deep‐sea terminal depositional fans and are present on all continental margins. The temporal morphological expression of such systems should be documented in order to fully understand the development of these important sediment pathways. We utilise a 3D seismic dataset from the northern Shetland Platform to the southern Møre Basin region and map two regionally continuous seismic horizons. The dataset includes an early Eocene northward‐oriented canyon‐channel system that allows high‐resolution mapping of erosion and sedimentation. The morphology of the system allows a subdivision of platform, upper, middle, and lower slope, and basin floor. It is further subdivided from east to west according to the degree of erosive maturity. The platform contains channel shapes and their fill stretching from the south towards the platform edge and upper slope, where dendritic canyon heads developed. Scars in the canyon sidewalls indicate slope failure as an important widening mechanism. The slope canyons progressively shallow and widen basinward. At the canyon exits, deepwater submarine channels developed and continued onto the basin floor. We document progressive filling and overspilling of channels towards the terminal fan. The filling of the channels that resulted in overbank deposition is likely due to a decrease in slope gradient leading to an increased deposition rate that exceeds the channel capacity. Post‐depositional differential compaction of the clastic channel fill and the surrounding muddy sediments causes the channel fills to form elongated ridges that lead towards the terminal fan. It is further shown that the morphological elements observed in the canyon‐channel system adjust towards an equilibrium profile with a shallower gradient. These detailed observations provide an enhanced understanding of how canyon‐channel systems develop on active margins and how sediment transport pathways are influenced by the submarine equilibrium profile and post‐depositional processes.

• Nygaard, Madeleine Skov; Planke, Sverre; Zastrozhnov, Dmitry; Midtkandal, Ivar; Huismans, Ritske Sipke & Faleide, Jan Inge [Show all 13 contributors for this article] (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. Full text in Research Archive Show summary

  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.

• Senger, Kim; Ammerlaan, Fenna; Betlem, Peter; Dumais, Marie-Andrée; Eagles, Graeme & Foster, William [Show all 29 contributors for this article] (2025). Geology of Svalbard: Deep-time and Deep-Earth (SVALGEOL). In Neuber, R.; Łupikasza, E.; Hübner, C. & Holmén, K. (Ed.), The State of Environmental Science in Svalbard – an annual report. Svalbard Integrated Arctic Earth Observing System. ISSN 9788293871149. p. 52–83. doi: 10.5281/zenodo.14425478. Full text in Research Archive Show summary

  Geology is omnipresent in Svalbard, defining among other parameters the location of all major settlements. The SVALGEOL chapter provides an overview of the geology of Svalbard, and how it influences local and global society. We briefly describe the history of geological exploration and mapping of Svalbard, before outlining the various data sets geoscientists use in their work. We then focus on two key aspects of geology: the study of “deep-time” (i.e., rocks older than 2.58 million years; the pre-Quaternary period) and the study of “deep-Earth” (i.e., integration of data from Earth’s surface to the interior). By investigating the Earth System at the scale of millions to billions of years, geologists can decipher how the global climate has varied through time. Furthermore, studying different proxies allows us to investigate the processes linking the geosphere with the biosphere (e.g., evolution of life, recovery following mass extinctions). By using field and various geophysical data, geologists can understand the properties of the Earth from its surface to its core, and the processes causing them. Furthermore, by coupling deep, shallow and surface observations with a time component, geoscientists can characterise the underlying processes that also influence society (e.g., natural gas emissions, permafrost development, geothermal potential, earthquakes)

• Abdelmalak, Mohamed Mansour; Rossetti, Lucas M.; Millett, John M.; Planke, Sverre; Jerram, Dougal Alexander & Faleide, Jan Inge [Show all 7 contributors for this article] (2025). Breakup Magmatism in the South Atlantic: Mechanisms and Implications. Earth-Science Reviews. ISSN 0012-8252. 264. doi: 10.1016/j.earscirev.2025.105088. Full text in Research Archive Show summary

  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 [Show all 8 contributors for this article] (2025). Møre–Vøring Composite Tectono-Sedimentary Element, Norwegian Rifted Margin, Norwegian Sea. Geological Society of London Memoirs. ISSN 0435-4052. 57, p. 174–196. doi: 10.1144/M57-2023-14. Full text in Research Archive Show summary

  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.

• Millett, J.M.; Jolley, D.W.; Hole, M.J.; Augland, Lars Eivind; Pugsley, J.H. & McLeod, G.W. [Show all 7 contributors for this article] (2024). High-precision U/Pb zircon dating of explosive volcanism in an early bi-modal volcano-sedimentary sequence from the Isle of Mull, North Atlantic Igneous Province. Lithos. ISSN 0024-4937. 482-483. doi: 10.1016/j.lithos.2024.107729. Full text in Research Archive Show summary

  The North Atlantic Igneous Province (NAIP) forms one of the best studied Large Igneous Provinces (LIP) on the planet, however, significant uncertainties regarding the age and nature of the early onset of volcanism across the province remain. In order to better understand the onset and timing of volcanism within the NAIP, we present a new study of the mixed volcano-sedimentary deposits exposed at the base of the Isle of Mull lava pile, Inner Hebrides, Scotland. The study area comprises organic rich estuarine sediments, intimately mixed and interdigitated with bi-modal composition volcaniclastic and pyroclastic interlayers, including a prominent stratigraphically constrained c. 30 cm thick water-lain rhyolitic ignimbrite. Pristine magmatic zircons liberated from the ignimbrite reveal a high precision Usingle bondPb age of 62.035 ± 0.041 Ma (2σ) giving a robust age for early volcanism in this part of the province. Field observations reveal evidence for mafic phreatomagmatic eruptive deposits both above and below the rhyolite documenting the bimodal explosive nature of the initial magmatism in this area and, importantly, that mafic magmatism initiated before the dated unit. The bi-modal explosive eruptions periodically inundated an otherwise quiet and low energy Danian aged estuarine environment prior to its inundation with lava as magmatism took hold in the region.

• Millett, John M.; Rossetti, Lucas; Bischoff, Alan; Rossetti, Marcos; Rosenqvist, Marija Plahter & Avseth, Per Åge [Show all 11 contributors for this article] (2024). Lava flow-hosted reservoirs: a review. Geological Society Special Publication. ISSN 0305-8719. 547(1), p. 357–387. doi: 10.1144/SP547-2023-102. Full text in Research Archive Show summary

  Lava flows form important fluid reservoirs and have been extensively exploited for water aquifers, geothermal energy, hydrocarbon production and, more recently, for carbon storage. Effusive subaerial mafic to intermediate lava flows account for vast rock volumes globally, and form reservoirs with properties dictated by well-known lava flow facies ranging from pāhoehoe through several transitional forms to ‘a’ā lava. These variations in flow type lead to critical differences in the pore structure, distribution, connectivity, strength and fracturing of individual lava flows, which, alongside lava flow package architectures, determine primary reservoir potential. Lava flow margins with vesicular, fracture and often autobreccia-hosted pore structures can have porosities commonly exceeding 40% and matrix permeabilities over 10−11 m2 (>10 D) separated by much lower porosity and permeability flow interiors. Secondary post-emplacement physicochemical changes related to fracturing, meteoric, diagenetic and hydrothermal alteration can significantly modify reservoir potential through a complex interplay of mineral transformation, pore-clogging secondary minerals and dissolution, which must be carefully characterized and assessed during exploration and appraisal. Within this contribution, a review of selected global lava flow-hosted reservoir occurrences is presented, followed by a discussion of the factors that influence lava flow reservoir potential.

• Garcia, Aurora Machado; Bellwald, Benjamin; Planke, Sverre; Anell, Ingrid; Myklebust, Reidun & Sternai, Pietro [Show all 7 contributors for this article] (2024). Sedimentation record of a complete glacial-interglacial cycle: Down-slope deposits, contourites and plumites of the North Sea trough mouth fan. Quaternary Science Reviews. ISSN 0277-3791. 339. doi: 10.1016/j.quascirev.2024.108839. Full text in Research Archive Show summary

  Trough mouth fans (TMFs) are major submarine depocentres that form in front of ice streams advancing onto the continental shelf, and they provide extensive records of past glaciations and ice-sheet dynamics. However, early research about TMFs was conducted using primarily 2D seismic data, which limits the insights on the deposit's geometries and internal structures and more recent studies using 3D data have focused on the general depositional history of TMFs. Here, we assess the spatial and temporal changes of the glacio-marine landforms and deposits throughout the last glacial-interglacial cycle (Marine Isotope Stage (MIS) 6 to 1, ∼130 ka to present) recorded in a >550 m thick progradational sequence. We use 3D reflection seismic data with significant vertical resolution (up to 2 m) imaging over 14000 km2 from the uppermost North Sea Fan (NSF) to document the seismic stratigraphy and sedimentary processes, by combining horizon picking and geomorphological analyses. The studied interval comprises five mappable units, four on the slope and one on the shelf, spanning from the modern seabed down to the top of the Tampen Slide (∼130 ka). Five different channel types (here included slide scars), as well as contourite and plumite packages are described based on their seismic facies, morphology, geometry, and stratigraphical position. We propose that contour currents are responsible for sediment delivery after the Tampen Slide deposition during the interglacial period before the onset of the Last Glacial Maximum, when high meltwater influx from the shelf produced turbidites. Sedimentation became debris-flow-dominated towards the end of the period of shelf-edge glaciation. The deglacial interval is characterized by the deposition of plumites on the slope. On the shelf, subglacial tills are deposited during both glacial and deglacial periods. We calculate an average sedimentation rate of <1 m/kyr during the interglacial (MIS 5-3), and around 50–65 m/kyr during the glacial and deglacial periods (MIS2-early MIS1). Thus, we document a change of two orders of magnitude in sedimentation rate during a glacial cycle on the slope of a glaciated margin.

• Famelli, Natália; Millett, John; Hole, Malcolm; Jerram, Dougal Alexander; Oliveira, Leonardo C. de & Lima, Evandro F. [Show all 12 contributors for this article] (2024). Understanding the petrophysical properties, seismic responses and impacts of the basalt-sediment transition in prospective sedimentary basins. Journal of South American Earth Sciences. ISSN 0895-9811. 148. doi: 10.1016/j.jsames.2024.105113. Full text in Research Archive
• Faleide, Jan Inge; Wong, Po Wan; Hassaan, Muhammad; Gabrielsen, Roy Helge; Abdelmalak, Mohamed Mansour & Planke, Sverre [Show all 9 contributors for this article] (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. Full text in Research Archive Show summary

  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.

• Lovecchio, Juan Pablo; Abdelmalak, Mohamed Mansour; Planke, Sverre; Silio, Ofelia Soledad; Rohais, Sébastien & Arismendi, Sebastián [Show all 10 contributors for this article] (2024). Mesozoic rifting in SW Gondwana and break-up of the Southern South Atlantic Ocean. Geological Society Special Publication. ISSN 0305-8719. 547(1), p. 75–107. doi: 10.1144/SP547-2023-140. Full text in Research Archive
• 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. Full text in Research Archive
• Bellwald, Benjamin; Manton, Ben; Lebedeva-Ivanova, Nina; Zastrozhnov, Dmitry; Myklebust, Reidun & Planke, Sverre [Show all 9 contributors for this article] (2024). Rapid glacial sedimentation and overpressure in oozes causing large craters on the mid-Norwegian margin: integrated interpretation of the Naust, Kai and Brygge formations. Geological Society Special Publication. ISSN 0305-8719. 525(1), p. 77–109. doi: 10.1144/SP525-2023-25. Full text in Research Archive
• Faleide, Jan Inge; Abdelmalak, Mohamed Mansour; Zastrozhnov, Dmitrii; Lasabuda, Amando P. E.; Hjelstuen, Berit Oline Blihovde & Laberg, Jan Sverre [Show all 7 contributors for this article] (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. Full text in Research Archive Show summary

  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

• Morris, A.M.; Lambart, S.; Stearns, M.A.; Bowman, J.R.; Jones, Morgan Thomas & Mohn, G. [Show all 30 contributors for this article] (2024). Evidence for Low-Pressure Crustal Anatexis During the Northeast Atlantic Break-Up. Geochemistry Geophysics Geosystems. 25(7). doi: 10.1029/2023GC011413. Full text in Research Archive
• Huebner, Nico; Fowler, Jim; Manton, Ben; Zastrozhnov, Dmitrii; Planke, Sverre & Badics, Balasz [Show all 7 contributors for this article] (2024). Sub-Basalt Hydrocarbon Exploration at the Vøring Marginal High, 85th EAGE Annual Conference & Exhibition. European Association of Geoscientists and Engineers (EAGE). ISSN 9789462824980. doi: 10.3997/2214-4609.202410990. Full text in Research Archive
• Maharjan, Dwarika; Planke, Sverre; Bellwald, Benjamin; Millett, John M.; Abdelmalak, Mohamed Mansour & Manton, Ben [Show all 9 contributors for this article] (2024). Rapid loading and deformation of soft sediments during emplacement of a Lava Delta in the Vøring Basin, Mid-Norwegian Margin. Geological Society Special Publication. ISSN 0305-8719. 547(1), p. 465–482. doi: 10.6084/m9.figshare.c.6946691.v1. Full text in Research Archive
• Manton, Ben; Millett, John; Zastrozhnov, Dmitrii; Lebedeva-Ivanova, Nina N.; Planke, Sverre & Myklebust, Reidun [Show all 7 contributors for this article] (2024). Sedimentary and Volcanic Systems at the Flanks of the South Gjallar Ridge, offshore Norway, 85th EAGE Annual Conference & Exhibition. European Association of Geoscientists and Engineers (EAGE). ISSN 9789462824980. doi: 10.3997/2214-4609.2024101544. Full text in Research Archive
• Senger, Kim; Betlem, Peter; Helland-Hansen, Annikken; Horota, Rafael Kenji; Kämpf, Horst & Kontny, Agnes M. [Show all 11 contributors for this article] (2024). Multi-disciplinary geoscientific expedition to Woodfjorden, NW Svalbard: Field sites, methods, and preliminary results. Czech Polar Reports. ISSN 1805-0689. 13(2), p. 142–161. doi: 10.5817/CPR2023-2-12. Full text in Research Archive Show summary

  The Woodfjorden area of northern Spitsbergen (NW Svalbard) offers access to the world’s northernmost onshore thermal springs, extinct Pleistocene alkali basaltic volcanoes and Miocene flood basalts including extensive hyaloclastites. In July 2023, we undertook a 14-day international multi-disciplinary geoscientific expedition to Woodfjorden-Bockfjorden to investigate the Cenozoic geological evolution of the area. The expedition objectives spanned a wide range of scientific topics from sampling of fluids and gas in the thermal springs to constraining the lithosphere by acquiring magnetotelluric data and sampling volcanic rocks. More specifically, we have 1) conducted gas, fluid and travertine sampling at the thermal springs of Gygrekjelda, Jotunkjeldene and Trollkjeldene, 2) mapped and sampled the Quaternary volcanic centers at Sverrefjellet and Halvdanpiggen, 3) sampled the Miocene basalts of the Seidfjellet Formation along seven profiles plus the underlying Devonian sedimentary rocks, 4) acquired magnetotell

• Vickers, Madeleine Larissa; Jones, Morgan Thomas; Longman, Jack; Evans, David; Ullmann, Clemens V. & Stokke, Ella Wulfsberg [Show all 33 contributors for this article] (2024). Paleocene-Eocene age glendonites from the Mid-Norwegian Margin - indicators of cold snaps in the hothouse? Climate of the Past. ISSN 1814-9324. 20, p. 1–23. doi: 10.5194/cp-20-1-2024. Full text in Research Archive Show summary

  Abstract. The International Ocean Discovery Program (IODP) Expedition 396 to the mid-Norwegian margin recovered &gt; 1300 m of pristinely preserved, volcanic-ash-rich sediments deposited during the late Paleocene and early Eocene from close to the centre of the North Atlantic Igneous Province (NAIP). Remarkably, many of these cores contain glendonites, pseudomorphs after the purported cold-water mineral ikaite, from sediments dated to the late Paleocene and early Eocene. These time intervals span some of the hottest climates of the Cenozoic, including the Paleocene–Eocene Thermal Maximum (PETM). Global deep-ocean temperatures are not thought to have dropped below 10 ∘C at any point during this time, making the occurrence of supposedly cold-water (near-freezing temperature) glendonite pseudomorphs seemingly paradoxical. This study presents a detailed sedimentological, geochemical, and microscopic study of the IODP Exp. 396 glendonites and presents an updated model for the ikaite-to-calcite transformation for these glendonites. Specifically, we show that early diagenesis of basaltic ashes of the NAIP appear to have chemically promoted ikaite growth in the sediments in this region. Together with existing knowledge of late Paleocene and early Eocene glendonites from Svalbard to the north and early Eocene glendonites from Denmark to the south, these new glendonite finds possibly imply episodic, short-duration, and likely localized cooling in the Nordic Seas region, which may have been directly or indirectly linked to the emplacement of the NAIP.

• Bellwald, Benjamin; Maharjan, Dwarika; Planke, Sverre; Winsborrow, Monica Caroline Mackay; Rydningen, Tom Arne & Alexandropoulou, Nikolitsa [Show all 7 contributors for this article] (2024). Major tunnel valleys and sedimentation changes document extensive Early Pleistocene glaciations of the Barents Sea. Communications Earth & Environment. 5. doi: 10.1038/s43247-024-01688-x. Full text in Research Archive Show summary

  Sedimentary records of Early Pleistocene (~2.6–0.8 Ma) glaciations are sparse on shelves, yet trough mouth fans on adjacent continental slopes provide a continuous record of ice-sheet and climate development throughout the Quaternary. Here, we interpret high-quality 3D seismic reflection data combined with borehole and chronostratigraphic information from a shelf-slope setting in the southwestern Barents Sea to study meltwater and sediment inputs to the deep ocean, focusing on the onset of Pleistocene glaciations. Sandy deposits were brought to the slopes of the high-latitude Bear Island Fan by a preglacial contourite-turbidite system from ⁓2.6–2.4 Ma. Muddy glacigenic debris flows document the first shelf-edge glaciation at ⁓2.4 Ma. From 1.78–0.78 Ma, muddy turbidity-current- and debris-flow-derived sediments were delivered from shelf to slope via six tunnel valleys measuring up to 12 km in width and 200 m in depth. These tunnel valleys and associated downslope deposits formed during the 41-kyr climate cycles of the Early Pleistocene, and evidence abundant channelized, meltwater discharges from these glaciations. Following the mid-Pleistocene transition to 100-kyr cycles, a change in the style of glaciation is suggested by a change in landform and facies associations consistent with a reduced meltwater contribution. This study shows that the Norwegian-Barents shelf was extensively glaciated in the Early Pleistocene, with a first shelf-edge glaciation from ~2.4 Ma

• Corseri, Romain; Seillé, Hoel; Faleide, Jan Inge; Planke, Sverre; Senger, Kim & Abdelmalak, Mohamed Mansour [Show all 9 contributors for this article] (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), p. 420–432. doi: 10.1093/gji/ggae166. Full text in Research Archive Show summary

  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.

• Rosenqvist, Marija Plahter; Millett, John M.; Planke, Sverre; Johannesen, Rakul Maria Ingunardóttir; Passey, Simon R. & Sørensen, Erik V. [Show all 8 contributors for this article] (2024). The architecture of basalt reservoirs in the North Atlantic Igneous Province with implications for basalt carbon sequestration. Geological Society Special Publication. ISSN 0305-8719. 547(1), p. 389–413. doi: 10.1144/SP547-2023-96. Full text in Research Archive Show summary

  Offshore CO2 sequestration in basaltic formations of the North Atlantic Igneous Province may allow permanent storage of large volumes of CO2 through rapid carbonate mineralization. Characterizing the internal architecture of such reservoirs is key to assessing the storage potential. In this study, six photogrammetry models and three boreholes on the Faroe Islands have been used to characterize the internal lava sequence architectures as a direct analogue to potential offshore North Atlantic Igneous Province storage sites. The studied formations are dominated by c. 5 to 50 m thick simple and compound lava flows, with drill core observations documenting a transition from pāhoehoe moving towards ‘a’ā lava flow types interbedded with thin (<5 m thick) volcaniclastic rock units. The identification of flow margin breccias is potentially important as these units form excellent reservoirs in several other localities globally. Stacked, thick simple flows may present sealing units associated with dense flow interiors. Connected porous and permeable lava flow crusts present potential reservoirs; however, the degree of secondary mineralization and alteration can alter initially good reservoir units to impermeable barriers for fluid flow. Large-scale reservoir volumes may be present mainly within both vesicular, fractured pāhoehoe and brecciated flow margins of transitional simple lava flows.

• Gernigon, Laurent; Knies, Jochen Manfred; Schönenberger, Jasmin; Piraquive, Alejandro; Lelij, Roelant van der & Huyskens, Magdalena H. [Show all 12 contributors for this article] (2024). Understanding volcanic margin evolution through the lens of Norway's youngest granite. Terra Nova. ISSN 0954-4879. 36(4), p. 250–257. doi: 10.1111/ter.12705. Full text in Research Archive
• Galland, Olivier; Villar, Héctor J.; Mescua, José; Jerram, Dougal Alexander; Messager, Gregoire Eugene Philippe & Medialdea, Adrian [Show all 11 contributors for this article] (2024). Structural control of igneous intrusions on fluid migration in sedimentary basins: the case study of large bitumen seeps at Cerro Alquitrán and Cerro La Paloma, northern Neuquén Basin, Argentina. Geological Society Special Publication. ISSN 0305-8719. 547(1), p. 231–259. doi: 10.1144/SP547-2023-115. Full text in Research Archive
• Kjøll, Hans Jørgen; Midtkandal, Ivar; Planke, Sverre; Millett, John; Manton, Ben & Anderskouv, Kresten (2023). The interplay between siliciclastic and carbonate depositional systems: Maastrichtian to Danian basin-floor sediments of the mid-Norwegian Møre Basin. Basin Research. ISSN 0950-091X. 36(1). doi: 10.1111/bre.12827. Full text in Research Archive Show summary

  Abstract Source‐to‐sink sedimentary systems associated with volcanic rifted margins serve as important archives for basin development by recording lithospheric changes affecting the depositional systems. Distinguishing between sediment transport processes and their sediment source(s) can guide the interpretation of a basin's history, and thereby inform regional paleogeographic reconstructions. In this contribution, we integrate and utilize wireline geophysical logs, detailed petrographic observations from side‐wall cores, and seismic analysis to describe and decipher a Maastrichtian to Danian‐aged basin‐floor depositional system in the deep outer Møre Basin, mid‐Norwegian margin. Well 6302/6‐1 (Tulipan) is a spatially isolated borehole drilled in 2001 that penetrates Maastrichtian and younger strata. A succession of hitherto undescribed carbonates and sandstones in the outer Møre Basin was discovered. It is investigated for sediment transport, provenance, and depositional processes on the basin floor surrounded by structural highs and ridges. The strata from the lower parts form a basin‐floor apron consisting of redeposited carbonate sourced from a westerly sub‐aerial high. The apron transitions vertically from mixed siliciclastic and carbonate into a purely siliciclastic fan with intercalated sandstone and mudstone, providing a rare high‐resolution record of how depositional environments experience a complete shift in dominant processes. The development coincides with similar latest Cretaceous‐earliest Palaeocene sequences recorded south of this region (e.g., well 219/20‐1) and may have been influenced by regional uplift associated with the onset of magmatism in the Northeast Atlantic. This study improves our understanding of a late, pre‐breakup source‐to‐sink sedimentary system developed near the breakup axis of an infant ocean, and documents what is possibly the northernmost chalk deposit in the Chalk Group.

• Berndt, Christian; Planke, Sverre; Zarikian, Carlos A. Alvarez; Frieling, Joost; Jones, Morgan Thomas & Millett, John M. [Show all 36 contributors for this article] (2023). Shallow-water hydrothermal venting linked to the Palaeocene–Eocene Thermal Maximum. Nature Geoscience. ISSN 1752-0894. 16, p. 803–809. doi: 10.1038/s41561-023-01246-8. Full text in Research Archive Show summary

  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.

• Planke, Sverre; Christian, Berndt; A, Alvarez Zarikian Carlos & 396, Scientific Party Expedition (2023). Mid-Norwegian Margin Magmatism and Paleoclimate Implications. Proceedings of the International Ocean Discovery Program. Expedition reports. doi: 10.14379/iodp.proc.396.2023. Full text in Research Archive
• Rosenqvist, Marija Plahter; Meakins, Max William John; Planke, Sverre; Millett, John M.; Kjøll, Hans Jørgen & Voigt, Martin J. [Show all 7 contributors for this article] (2023). Reservoir properties and reactivity of the Faroe Islands Basalt Group: Investigating the potential for CO<inf>2</inf> storage in the North Atlantic Igneous Province. International Journal of Greenhouse Gas Control. ISSN 1750-5836. 123. doi: 10.1016/j.ijggc.2023.103838. Full text in Research Archive Show summary

  Offshore injection of CO2 into volcanic sequences of the North Atlantic Igneous Province may present a large-scale, permanent storage option through carbonate mineralization. To investigate this potential, onshore studies of reservoir properties and reactivity of the subaerially erupted Faroe Islands Basalt Group have been conducted. Outcrop and borehole samples reveal that the lava flow crusts commonly contain vesicles that have been filled with secondary minerals due to hydrothermal fluid circulation, however, unmineralized and highly porous layers do occur. Bulk density measurements, micro-computed tomography (µ-CT) image analysis, and microscope studies of samples from onshore boreholes give present-day porosities ranging from 0.5% to 36.2% in the volcanic sequences. The unmineralized brecciated lava flow crusts contain the largest estimated porosity and simulated absolute permeability (reaching up to 10−12 m2). µ-CT studies of the mineralized, brecciated flow crusts indicate initial porosities reaching up to 45%, before clogging. Kinetic experiments of rock dissolution show that the reactivity of the basalt and volcaniclastic sediments depends on the alteration state with more altered basalt being less reactive. However, the presence of reactive, high porosity, and high permeability flow crusts prior to clogging indicate the existence of promising and very large CO2 reservoirs in less altered offshore sequences.

• Senger, Kim; Kulhanek, Denise; Jones, Morgan Thomas; Smyrak-Sikora, Aleksandra; Planke, Sverre & Zuchuat, Valentin [Show all 13 contributors for this article] (2023). Deep-time Arctic climate archives: high-resolution coring of Svalbard's sedimentary record – SVALCLIME, a workshop report. Scientific Drilling. ISSN 1816-8957. 32, p. 113–135. doi: 10.5194/sd-32-113-2023. Full text in Research Archive Show summary

  ​​​​​​​We held the MagellanPlus workshop SVALCLIME “Deep-time Arctic climate archives: high-resolution coring of Svalbard's sedimentary record”, from 18 to 21 October​​​​​​​ 2022 in Longyearbyen, to discuss scientific drilling of the unique high-resolution climate archives of Neoproterozoic to Paleogene age present in the sedimentary record of Svalbard. Svalbard is globally unique in that it facilitates scientific coring across multiple stratigraphic intervals within a relatively small area. The polar location of Svalbard for some of the Mesozoic and the entire Cenozoic makes sites in Svalbard highly complementary to the more easily accessible mid-latitude sites, allowing for investigation of the polar amplification effect over geological time. The workshop focused on how understanding the geological history of Svalbard can improve our ability to predict future environmental changes, especially at higher latitudes. This topic is highly relevant for the ICDP 2020–2030 Science Plan Theme 4 “Environmental Change” and Theme 1 “Geodynamic Processes”. We concluded that systematic coring of selected Paleozoic, Mesozoic, and Paleogene age sediments in the Arctic should provide important new constraints on deep-time climate change events and the evolution of Earth's hydrosphere–atmosphere–biosphere system. We developed a scientific plan to address three main objectives through scientific onshore drilling on Svalbard: a. Investigate the coevolution of life and repeated icehouse–greenhouse climate transitions, likely forced by orbital variations, by coring Neoproterozoic and Paleozoic glacial and interglacial intervals in the Cryogenian (“Snowball/Slushball Earth”) and late Carboniferous to early Permian time periods. b. Assess the impact of Mesozoic Large Igneous Province emplacement on rapid climate change and mass extinctions, including the end-Permian mass extinction, the end-Triassic mass extinction, the Jenkyns Event (Toarcian Oceanic Anoxic Event), the Jurassic Volgian Carbon Isotopic Excursion and the Cretaceous Weissert Event and Oceanic Anoxic Event 1a. c. Examine the early Eocene hothouse and subsequent transition to a coolhouse world in the Oligocene by coring Paleogene sediments, including records of the Paleocene–Eocene Thermal Maximum, the Eocene Thermal Maximum 2, and the Eocene–Oligocene transition. The SVALCLIME science team created plans for a 3-year drilling programme using two platforms: (1) a lightweight coring system for holes of ∼ 100 m length (4–6 sites) and (2) a larger platform that can drill deep holes of up to ∼ 2 km (1–2 sites). In situ wireline log data and fluid samples will be collected in the holes, and core description and sampling will take place at The University Centre in Svalbard (UNIS) in Longyearbyen. The results from the proposed scientific drilling will be integrated with existing industry and scientific boreholes to establish an almost continuous succession of geological environmental data spanning the Phanerozoic. The results will significantly advance our understanding of how the interplay of internal and external Earth processes are linked with global climate change dynamics, the evolution of life, and mass extinctions.

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• Polteau, Stephane; Smalley, P. Craig; Devegowda, Vani; Millett, John; Rosenqvist, Marija Plahter & Abdelmalak, Mohamed Mansour [Show all 8 contributors for this article] (2026). Well-connected basalt sequences as potential reservoirs for large-scale carbon sequestration revealed by strontium isotopes. doi: https:/www.egu26.eu/. Full text in Research Archive Show summary

  Basalt complexes can cover hundreds to thousands of km2 and be several km thick; with an estimated global capacity of 40 Tt for carbon storage, they represent a solution for the large-scale injection of CO2 to reach the 2050 emission targets. However, the hydraulic conductivity of basalt sequences is difficult to predict because it has never been the focus in basalt research. In this contribution, we evaluate for the first time the vertical fluid connectivity of a basalt sequence using the Sr isotope composition of pore waters, sampled using the strontium residual salt analysis (SrRSA) method. Thirty seven samples were collected in the U1571A borehole (IODP Expedition 396 on the Skoll High, offshore Mid-Norway). Sampling of the well targeted the most representative lithologies in the core, and hence included vesicular and tight basalt. The SrRSA method measures the 87Sr/86Sr ratio in the salt residue that precipitated in the pores of core samples after the pore water evaporated, and the value measured in the laboratory should accurately reflect that of the in situ pore water. However, since the well was drilled using seawater with barite and sepiolite additives, each sample was washed in de-ionized water to reduce potential contamination. The samples were subsequently dried, crushed, the salts were leached, the leachate filtered, and the strontium analyzed using a MC-ICPS. The results show that the Sr concentrations are very low: 1-35 ppb in vesicular basalt samples and up to 2 ppb in tight basalt samples. The 87Sr/86Sr ratio of the vesicular basalt varies little away from the average value of 0.7085, while the values of tight basalts show more variability with an average of 0.7093. The SrRSA pattern vs. depth for the vesicular basalt samples is smooth, indicating limited contamination from drilling fluids, and further suggesting a good vertical connectivity. On the other hand, the pattern of the tight basalts is shifted towards heavier values similar to modern seawater, suggesting the SrRSA for these samples to be contaminated by the drilling fluids. In addition to the residual salts, we are currently analyzing the 87Sr/86Sr in carbonate vesicles and in basalt, which together represent the three main reservoirs of strontium in the samples. These additional results should help us constrain the source of the strontium in the pore system (i.e.: external, flowing or diffusing through the sequence). These results further show that the fluid connectivity of basalt sequences can be characterized using the SrRSA method by focusing the analyses on vesicular basalt samples. Finaly, this study will provide additional constrains to follow-up numerical models simulating the injectivity and capacity of intra- and inter-basalt reservoir units.

• Polteau, Stephane; Smalley, P. Craig; Devegowda, Vani; Johansen, Ingar; Millett, John & Rosenqvist, Marija Plahter [Show all 8 contributors for this article] (2026). Fluid connectivity and evolution of pore water in breakup basalt offshore mid-Norway with implications for CO2 storage. doi: https:/ngwm2026.fi/. Full text in Research Archive Show summary

  Basalt complexes can cover thousands of square kilometres and be several kilometres thick. With an estimated global carbon storage capacity of 40 Tt they represent a possible solution to reach the 2050 emission targets. However, the injection of gigatons of CO2 into basaltic formations requires a thick reservoir system lacking barriers to lateral fluid flow for the CO2 to dissipate away from injection points. In this contribution, we evaluate for the first time the vertical fluid connectivity of a basalt sequence using the Sr isotope composition of pore waters, sampled using the strontium residual salt analysis (SrRSA) method. Thirty-seven samples were collected in the U1571A borehole (IODP Expedition 396 on the Skoll High, offshore mid-Norway). Sampling of the well targeted the most representative lithologies and hence included vesicular basalt and massive flow interiors. The SrRSA method measures the 87Sr/86Sr ratio in the salt residue that precipitated in the pores of core samples after the pore water evaporated, and the value measured in the laboratory should accurately reflect that of the in-situ pore water. In addition to present-day pore water from the residual salts, the 87Sr/86Sr of past water compositions were reconstructed from carbonate cements of different ages. We reveal smooth and uninterrupted trends in strontium isotopes through a 100 m thick basalt section indicating a common fluid reservoir unaffected by the low-permeability massive lava flow interiors. The data further indicate that the unconsolidated overburden sediments act as a good seal preventing seawater to mix with in situ porewater and may prevent CO2 leakage to the surface for buoyant supercritical CO2 injection scenarios. This study supports the premise that basaltic sequences form viable targets for CO2 storage and suggests that fractures may bypass low-permeability units to create a well-connected reservoir system. Finally, the 87Sr/86Sr method is demonstrably useful in basalts, and warrants being included routinely in evaluating thick basalt sequences for large-scale CO2 storage.

• Polteau, Stephane; Smalley, P. Craig; Devegowda, Vani N.; Johansen, Ingar; Millett, John & Rosenqvist, Marija Plahter [Show all 8 contributors for this article] (2026). Fluid connectivity and evolution of pore water in breakup basalt offshore mid-Norway with implications for CO2 storage. doi: https:/ngwm2026.fi/conference-programme. Full text in Research Archive
• Svensen, Henrik Hovland & Planke, Sverre (2025). Potensialet for lagring av CO2 i vulkanske bergarter i Norge. Full text in Research Archive
• Tugend, Julie; Mohn, Geoffroy; Kusznir, Nick; Planke, Sverre; Berndt, Christian & Manton, Ben [Show all 8 contributors for this article] (2025). Palaeobathymetry of the Mid-Norwegian volcanic margin during continental breakup and paleoclimate implications. doi: 10.5194/egusphere-egu24-11873. Full text in Research Archive Show summary

  The Mid-Norwegian volcanic rifted margin and its NE-Greenland conjugate formed in relation to continental breakup in the latest Palaeocene to earliest Eocene during the emplacement of the North Atlantic Igneous Province (NAIP). The development of the NAIP and opening of the North Atlantic occurred contemporaneous to the Paleocene Eocene Thermal Maximum (PETM) which corresponded to a rapid 5-6&#160;&#176;C global warming episode.The cause of this rapid global warming, explored as part of IODP Expedition 396, is thought to relate to the thermogenic gases released to the atmosphere via thousands of hydrothermal vents. The thermogenic gases were produced by contact metamorphism of carbon-rich sediments during widespread sill emplacement from the NAIP. The potential of hydrothermally-released greenhouse gases to influence climate depends strongly on the water depth at which they get released. Unless it is released in a shallow marine environment most methane will be oxidized before it reaches the atmosphere.Early results from IODP Expedition 396 have documented that at least one of the Mid-Norwegian hydrothermal vents was emplaced in shallow marine to potentially sub-aerial conditions. The aim of this contribution is to constrain further the paleo-water depth at which hydrothermal vents formed along the other parts of the mid-Norwegian volcanic rifted margin. This study focuses on an integrated workflow of quantitative geophysical and geodynamic analyses calibrated by new IODP drilling results and structural and stratigraphic observations. We use a 3D flexural-backstripping, decompaction and reverse thermal subsidence modelling to predict the palaeobathymetry and palaeostructure at keys stages of the syn- to post-breakup evolution that can be compared with palaeo-water depths estimated from biostratigraphic data. Results provide new constraints on the paleobathymetry of hydrothermal vent complexes required to confirm whether the global warming recorded by the PETM was triggered by the magma-rich continental breakup leading to the opening of the northeast Atlantic Ocean.&#160;

• Millett, John; Planke, Sverre; Jolley, David; Berndt, Christian; Betlem, Peter & Rosenqvist, Marija Plahter [Show all 9 contributors for this article] (2025). Characterizing lava flows in offshore North Atlantic boreholes: a review with implications for basalt carbon storage. doi: 10.5194/egusphere-egu24-12383. Full text in Research Archive Show summary

  Widespread and large-scale volcanism associated with the North Atlantic Igneous Province (NAIP) erupted during the Paleocene and Early Eocene and covers vast regions of the conjugate North Atlantic rifted margins. The majority of the preserved volume occurs in the offshore sequences of the continental shelves of Greenland, the Faroe Islands, UK, and Norway. These vast mafic igneous rock volumes in the offshore NAIP have been proposed as a potential area for permanent CO2 storage. However, a wide range of factors influence the suitability of mafic rock masses to act as fluid reservoirs including perhaps most importantly the volcanic facies (and associated pore structure, permeability, and distribution), along with alteration state, fracturing, and reactivity. In this contribution we focus on assessing the nature, distribution, and reservoir potential of sub-aerial lava flows from available borehole data across the NAIP. Lava flows are chosen for focus as they represent the most favorable reservoir target identified to date whilst also often constituting the dominant facies within much of the accessible NAIP offshore sequences.Over 50 offshore boreholes have penetrated the lava sequences of the NAIP including both industry and scientific boreholes drilled from the 1970&#8217;s onwards. Boreholes have encountered anything from a single lava flow through to several 10&#8217;s of lava flows in volcanic sequences reaching over 2 km in cumulative thickness in the deepest industry wells such as Brugdan (6104/21-1) and Lagavulin (217/15-1z) in the Faroese and UK sectors respectively.A summary of the lava flow nature (simple, compound, thickness, core-crust ratios) and physical property ranges (P-wave velocity, density, resistivity) of the penetrated lava flow sequences is presented utilizing available core, sidewall core, wireline and drill cuttings data to support the facies appraisal.Borehole data and the level of possible interpretation vary significantly depending on the age, purpose, and importantly the drilling operations of the individual boreholes. Some of the most robust and complete datasets are represented by modern hydrocarbon industry boreholes, for example those from the Rosebank Field in the UK sector, and cored boreholes from recent IODP Expedition 396 drilling Mid-Norway. Results from Expedition 396 are presented to highlight formation evaluation approaches for NAIP lava flow sequences including assessing the effects of different lava flow facies on Net to Gross calculations and the impact of alteration and secondary alteration on wireline log responses.This study presents important new constraints on the nature, variability, and distribution of NAIP lava flows from extensive available borehole ground truth data forming a foundational study for the development of reservoir appraisal techniques in the province going forward.

• Rosenqvist, Marija Plahter; Dunkel, Kristina; Planke, Sverre; Nogueira, Liebert Parreiras; Polteau, Stephane & Menegon, Luca (2025). Porosity structures and local compositional variations associated with natural CO2 sequestration in basalts offshore Norway. doi: 10.5194/egusphere-egu25-11073. Full text in Research Archive Show summary

  Permanent storage of CO2 as carbonates in basalt deposits utilises natural weathering reactions between silicate minerals and carbonic water. By studying how CO2-enriched water has altered basalt in 43 samples from the V&#248;ring Margin, offshore Norway, we demonstrate the pathways and reactions of CO2 within a basalt reservoir.The pore spaces occupied by carbonates in the samples were studied through &#956;-CT (computer tomography) studies on three minicores and detailed microanalyses on 32 thin sections via scanning electron microscopy (SEM), electron microprobe analysis, and electron backscatter diffraction (EBSD). Single crystal X-ray diffraction on 15 samples determined the type of carbonate minerals and precipitation ages were determined for two samples through U/Pb-radiomeric dating. &#948;18O and &#948;13C-isotope analyses were used to determine the fluid origin in 11 samples.Three types of carbonate precipitation were characterised based on the pore structures they fill and the associated mineralogy. Type I carbonates, seen in 18 thin sections, fills vesicles, mainly along lava flow margins. SEM analyses showed that all vesicles are initially coated with a smectite layer which incorporates most of the Mg2+ and Fe2+ from dissolving silicate minerals. As pH and Ca concentrations increase, calcite precipitates in some vesicles. The secondary mineral assemblage and precipitation order fit with low-temperature alteration of basalt with pore water and atmospherically balanced CO2 levels (pH&#8805;8). Type II carbonates appear in seven thin sections as

• Tugend, Julie; Mohn, Geoffroy; Kusznir, Nick, J.; Planke, Sverre; Berndt, Christian & Zastrozhnov, Dmitrii [Show all 7 contributors for this article] (2025). Paleo-depth of hydrothermal venting along the Mid-Norwegian volcanic margin during Paleogene continental breakup. doi: 10.5194/egusphere-egu25-10746. Full text in Research Archive Show summary

  Volcanic rifted margins commonly form in association with the emplacement of Large Igneous Provinces. The intense associated volcanic activity coincides with shifts in the global carbon cycle and rapid climate change during several key geological periods and crises. The Mid-Norwegian and NE-Greenland conjugate rifted margins formed after late Paleocene to early Eocene continental breakup in association with the emplacement of the North Atlantic Igneous Province (NAIP). The NAIP and early opening of the North Atlantic occurred contemporaneous to a rapid 5-6&#160;&#176;C global warming episode known as the Paleocene Eocene Thermal Maximum (PETM). The rapid global warming documented during the PETM is hypothesized to result from the release of thermogenic gases into the atmosphere through thousands of hydrothermal vents. The gases were generated by contact metamorphism of carbon-rich sediments during the extensive sill emplacement from the NAIP. The potential climatic impact of these hydrothermally released greenhouse gases is dependent on the water depth at which they were released. Unless it is released in a shallow marine environment most methane, known for its significantly greater global warming potential compared to carbon dioxide, will be oxidized and dissolved in the ocean before it reaches the atmosphere.First results of IODP Expedition 396 conducted on the Mid-Norwegian volcanic margin have documented the shallow marine to potentially sub-aerial setting of at least one of the hydrothermal vents (i.e. Modgunn vent). However, a comprehensive regional assessment of the water depth at which hydrothermal venting occurred remains necessary to validate the overall impact on paleoclimate and the PETM. To do so, we apply 3D flexural-backstripping and decompaction to remove the loading effects of sedimentary sequences and determine the sediment-corrected bathymetry down to the top Palaeocene surface at which most of the vents are mapped. Reverse subsidence cannot be directly modelled without knowing the detailed distribution of syn- and post-rift thermal subsidence from Cretaceous and Paleocene rifting as well as any mantle plume dynamic uplift during NAIP emplacement. Because these tectonic and geodynamic components of subsidence cannot be deterministically predicted at the required accuracy, we use local palaeobathymetric constraints from seismic observations and drilled biostratigraphic data, combined with our flexural backstripping and decompaction results to calibrate palaeobathymetric variations of the Paleocene venting surface at the time of the PETM.Our results predict that hydrothermal venting occurred within a range of palaeo-water depths showing the complex palaeo-structure of the top Paleocene surface. Key post-Paleocene tectonic influences such as a well-documented Miocene doming episode influence the margin history, and hence, at this location, our palaeobathymetric results represent shallowest estimates and must be interpreted with caution. However, most of the vents (>80%) restore to bathymetries shallower than 500&#160;meters, i.e., in sub-aerial to shallow marine conditions. Our work aims to confirm and extend initial results of IODP Expedition 396 from the Modgunn vent. Shallow water-depth hydrothermal venting most likely occurred during magma-rich continental breakup and NAIP emplacement; a large part of the released hydrogenic gas could have directly contributed to the global warming recorded by the PETM.&#160;

• Galerne, Christophe; Sinha, Aniruddha; Bach, Wolfgang; Kahl, Wolf-Achim; Millett, John & Planke, Sverre (2025). Pore-fluid pressure assisted columnar joint initiation: a natural carbon trapping process revealed from IODP Expedition 396 basalt samples. doi: 10.5194/egusphere-egu25-20273. Full text in Research Archive Show summary

  Extensive flood basalt sequences of the North Atlantic Igneous Province (NAIP) offshore Norway comprise promising sequestration reservoirs for permanent CO2 on the doorstep of Europe. However, a key question remains open: How much of the pore space is available at present for Carbon Capture and Sequestration (CCS) endeavours?We investigated carbonate vein and void mineral fills in drill core samples from IODP Expedition 396 which recovered over 350 m of basaltic stratigraphy, to untangle the formation conditions of the carbonates and the origin of the carbon. We examined two main scenarios: carbonates originating from 1) dissolved carbon in seawater, or from 2) thermogenic gas ascending from greater depths within the basin. Several driving mechanisms for this second scenario are explored: natural migration of light petroleum derived from burial and/or contact metamorphism associated with later sill emplacement at depth.We present results of carbon and oxygen isotope analyses of carbonate found distributed down section of the landward-flow volcanic sequence (Site U1566) and the outer seaward-dipping reflector (SDR) sequence of flows (Site U1573). Oxygen isotope thermometry suggests a range of formation temperatures between 50 and 160&#176;C. However, results from micro-CT textural analyses and petro-chemical analyses suggests that some carbonate originated from thermogenic gas at much higher temperature. We interpret these signatures as relating to the early nucleation of contractional cooling joints (columnar joint fractures) in the basaltic lava at the time of emplacement. Newly obtained carbon and oxygen isotopes from this type of carbonate will be presented and discussed.Our result suggests an alternative third scenario in which carbonate originating from below the flood basalts seals the porosity and reduces permeability in the lower section of the SDR sequence. Textural analysis indicates that thermogenic gases mobilized during lava flow emplacement assist in initiating and sealing columnar joint fractures. If confirmed, this process implies that the SDR lava flow sequence above the first lava flow may be relatively carbonate-free, as it is sealed off from post-emplacement thermogenic gas fluxes ascending from depth.

• Johannesen, Rakul Maria Ingunardóttir; Galland, Olivier; Ólavsdóttir, Jana; Kjøll, Hans Jørgen; Eidesgaard, Óluva & Planke, Sverre (2025). Fractured basalts as reservoirs for permanent CO2 storage on the Faroe Islands. doi: 10.5194/egusphere-egu25-12801. Full text in Research Archive Show summary

  During the last decade, the pilot CarbFix project in the Iceland rift zone has provided highly promising results for permanently storing CO2 as carbonates in basalts. A key question is whether this method can be applied in other basaltic formations worldwide where the rocks are older, the porosities are lower, the chemical compositions are different, and/or the temperatures are lower. Storing CO2 in the subsurface necessitates injectivity, where two essential properties are permeability and porosity. In basaltic formations, porous volumes are typically found as vesicle zones, near lava flow boundaries and in flow tops, or fractures. Currently, it appears that the permeability necessary for injecting fluids in basalts is dominated by fractures. The Faroe Islands, in the North Atlantic, consist of layered basalts of Paleogene age. The aim of this study is to examine the potential of the Faroe Island Basalt Group (FIBG) as a CO2 reservoir. To evaluate the reservoir properties of the FIBG we interpret and integrate new and existing data at multiple scales, including satellite images, UAV photogrammetric surveys, and field mapping. We have determined the distribution of large-scale lineaments (faults and dykes), flow-scale fractures, and the interaction between them in three dimensions. Here, we focus on the Malinstindur Formation, a compound basalt sequence, which is a potential pilot injection sequence because of its permeability potential. Large-scale mapping of the FIBG volcanostratigraphy is used to map the depth of the Malinstindur Formation and to determine the presence of large strike-slip faults across the archipelago. In addition, large-scale structural lineaments exhibiting a preferred EW-trending orientation are mapped. In addition, fracture analyses on different scales (from islands to outcrops), have been conducted to investigate how lava flow architectures, regional stress, and faults control fracture distribution and connectivity. The results of these analyses show that (1) the fracture density decreases with flow thickness, (2) the orientation of the internal fractures follows the same as those of the sets of regional scale lineaments, and (3) there is no link between the fracture intensity in the basalts and the distance to the regional scale lineaments. This study will serve as a foundation for determining the subsurface distribution of the Malinstindur Formation and the fracture distribution and connectivity at potential injection sites in order to estimate the potential for permanent CO2 storage within the Faroe Islands.

• Planke, Sverre; Berndt, Christian; Huismans, Ritske Sipke; Faleide, Jan Inge; Bünz, Stefan & Millett, John [Show all 8 contributors for this article] (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. Full text in Research Archive
• Lebedeva-Ivanova, Nina N.; Bünz, Stefan; Berndt, Christian; Millett, John; Betlem, Peter & Zastrozhnov, Dmitry [Show all 9 contributors for this article] (2025). High-resolution 2D and 3D seismic imaging and core-log-seismic integration of seaward dipping reflectors on the Vøring volcanic rifted margin. doi: 10.5194/egusphere-egu25-12935. Full text in Research Archive Show summary

  Offshore basalt flow sequences represent potential permanent CO2 sequestration sites along volcanic rifted margins. The International Ocean Discovery Program (IODP) Expedition 396 drilled six basement sites on the V&#248;ring volcanic margin in 2021, recovering more than 350 m of basaltic basement cores and 15 m of granite cores. The cores have been extensively analyzed following the IODP shipboard procedures (e.g., velocity, density, porosity, and magnetic susceptibility measurements). In addition, shore-based petrographic, geochemical, CT scanning, and multi-fluid permeability and flow measurements (nitrogen, brine, liquid and gaseous CO2) have been performed to assess reservoir properties. A standard suite of conventional wireline logs along with borehole image (acoustic and resistivity) logs were acquired in four holes. High-resolution 2D and locally 3D seismic reflection data have been acquired across all sites during three surveys (2020, 2022, and 2024) using R/V Helmer Hansen. In total, four HR3D P-Cable cubes with a total areal extent of 62 km2 and c. 2700 km of HR2D data have been collected. The seismic data are interpreted using the concepts of seismic volcanostratigraphy and igneous seismic geomorphology combined with conventional horizon interpretation and core-log-seismic integration. On the Skoll High, the igneous seismic geomorphology of the Top Basalt horizon reveals two distinct domains: a pitted surface in the west, and a faulted surface in the east. Cross-cutting faults and fracture systems are well imaged in borehole data and the 3D seismic data. Borehole data show that the Inner Seaward Dipping Reflectors (SDR) were emplaced in subaerial and coastal environments, including vesicular flow tops and deposition of inter-basalt volcaniclastic sedimentary horizons. Vesicles are observed to be both open or filled with carbonates and clay minerals within different layers, however, laboratory measured matrix permeability of mini-core plugs is typically low and in the milli to micro-darcy range; brine permeability measurements are indicating even lower. Multiple scales of fracturing are identified within the cores and image logs, and Strontium residual salt analysis revealed that they have an important impact on permeability by enhancing fluid communication between flows. In conclusion, the integrated interpretation suggests that the V&#248;ring Margin basalt sequences may have reservoir potential in fractured intervals and flow tops, but reservoir-scale injection testing linked to fracture network parameterization is required for large-scale assessment.

• Planke, Sverre; Bünz, Stefan; Berndt, Christian; Zarikian, Carlos A. Alvarez; Lebedeva-Ivanova, Nina N. & Stokke, Henrik Henriksen [Show all 18 contributors for this article] (2025). The Ocean-Continent Transition of the Northern Vøring Margin from New High-Resolution 2D Seismic and IODP Expedition 396 Data. Full text in Research Archive
• Planke, Sverre (2025). Exploration history and opportunities in the Vøring volcanic basin. Full text in Research Archive
• Bünz, Stefan; Planke, Sverre; Berndt, Christian; Lebedeva-Ivanova, Nina N.; Stokke, Henrik Henriksen & Binde, Cornelia Mentzoni [Show all 14 contributors for this article] (2025). High-resolution 3D seismic imaging of Northeast Atlantic volcanic break‐up processes. doi: https:/www.geologi.no/konferanser/vinterkonferanser/abstracts/file/298-abst-vk25. Full text in Research Archive Show summary

  During the NE Atlantic breakup in the Paleogene, extensive magmatic activity resulted in the formation of approximately 6–10 Mkm3 of extrusive basaltic deposits and intrusion of magma into sedimentary basins. This magmatism, along with the degassing and explosive release of thermo‐ genic gases due to contact metamorphism, has been linked to the onset of the Paleocene‐Eocene Thermal Maximum (PETM; 56 Ma). During IODP Expedition 396, 21 boreholes were drilled at 10 sites across five geological settings on the mid‐ Norwegian Margin. These sites sampled diverse igneous and sedimentary environments, including lava flow fields, hydrothermal vent complexes (HTVCs), and thick Paleogene strata. In addition, UiT The Arctic University of Norway conducted three research expeditions in 2020, 2022 and 2024 to acquire high‐resolution 2D/3D seismic and multibeam data in order to tie IODP borehole sites together and to regional geology. This presentation focusses on the two high‐resolution 3D seismic surveys, one of which that was repeated during the 2024 expedition to study repeatability effects in basalts. A high‐resolution P‐Cable 3D seismic cube (10 by 2.4 km, 6.25x6.25 m bin size) was collected over the Modgunn Arch (Sites U1567 and U1568), where we have identified a shallowly buried HTVC, known as the Modgunn Vent, and associated sill intrusions. Contact metamorphism of sedimentary rocks generates volatile compounds, generating an overpressure that leads to fracturing of the overlying sediments. As the hot fluids and gases escape through the fractures, they reach the sea‐ floor and create HTVCs. These complexes consist of a large crater structure that is subsequently filled in by sediments some of which may result from erupted material. The vent fill may be alter‐ ed by fluid migration and/or tectonic stress leading to folding and doming. Another high‐resolution 3D seismic survey (10.3 x 1.8 km, 6.25x6.25 m bin size) was conducted on the Skoll High at the northern Vøring margin (Sites U1571 and U1572). The 3D seismic data images the top basalt showing the volcanic paleo‐land‐ scape in unprecedented details. A faulted and eroded lava horizon is observed in the southeast‐ ern cube at 150–250 m depth. In contrast, the northwestern cube shows a pitted surface with lobate structures and linear ridges. These features are interpreted as rootless cones, volcanic craters formed by explosive interactions between lava flows and water‐saturated sediments. This study showcases the exceptional level of detail achievable through high‐resolution 3D seis‐ mic data acquisition of hydrothermal vent complexes and buried volcanic landscapes, offering new opportunities for unique insights in the Northeast Atlantic break‐up processes and beyond

• Binde, Cornelia Mentzoni; Bünz, Stefan; Plaza-Faverola, Andreia; Planke, Sverre & Manton, Ben (2025). Hydrothermal vent complexes associated to the Infinity Sill, Vøring volcanic margin, offshore Norway. doi: https:/www.geologi.no/konferanser/vinterkonferanser/abstracts/file/298-abst-vk25. Full text in Research Archive Show summary

  Hydrothermal vent complexes (HTVCs) are pipe‐like fluid conduits formed in response to metamorphism of organic‐rich sedimentary strata in contact aureoles, venting thermogenic gases at the paleo‐seafloor following hydrofracturing and fluid migration. In the Møre and Vøring basins, extensive sill complexes were emplaced as part of the North Atlantic Igneous Province during the rifting and initial opening of the Norwegian‐Greenland Sea, near the Paleocene‐Eocene transition (c. 56 Ma ago). Hundreds of HTVCs were formed along sill margins, and the temporal coincidence between hydrothermal venting and the Paleocene‐Eocene Thermal Maximum (PETM) suggest that thermogenic gas release from sill aureoles may have contributed to increased temperatures at the Paleocene‐Eocene transition. To better understand the relationship between igneous intrusions and the formation of hydrothermal vent complexes, we are analyzing the distribution, seismic characteristics and morphology of HTVCs associated with the Infinity Sill, a large, elongated sill located in the southern Vøring Basin. We are using a 15 000 km2 3D seismic dataset (courtesy of TGS) across the border of the Møre and Vøring volcanic basins. 79 individual HTVCs, with vent conduits originating at the Infinity Sill margins and/or locals highs/sill steps, have been identified and classified into: i) along‐margin vents, distributed along the sill margins, ii) mid‐sill vents, distributed above the interior of the sill, and iii) mini‐vents, with vent diameters < ~350 m. Key observations from our study include: i) HTVCs occur as individual, amalgamated or clustered vents, ii) vents terminate at different sub surface levels, commonly at or below the regional vent horizon (Near Top Paleocene), iii) the majority of vents have eye‐shaped upper vent morphologies, with domed vent material and internal vent infill reflections, and iv) along‐margin and mid‐sill vents are characterized by radial and concentric faulting. We find that the formation and distribution of hydrothermal vent complexes associated to the Infinity Sill likely reflect variations in sill geometry, fluid generation potentials and/or migration pathways in the sill aureole, ultimately controlling the upper vent termination, size, number and distance between HTVCs

• Polteau, Stephane; Smalley, Craig; Millett, John; Planke, Sverre; Rosenqvist, Marija Plahter & Devegowda, Vani [Show all 7 contributors for this article] (2025). Vertical fluid connectivity of basalt sequence assessed using strontium isotopes in pore waters. Full text in Research Archive
• Polteau, Stephane; Craig, Smalley,; Millett, John; Planke, Sverre; Rosenqvist, Marija Plahter & V., Devegowda, [Show all 7 contributors for this article] (2025). The fluid connectivity of continental margin basalt sequences for CO2 storage revealed by strontium isotopes. Full text in Research Archive
• Nygaard, Madeleine Skov; Planke, Sverre; Berndt, Christian; Zastrozhnov, Dmitry; Faleide, Jan Inge & Jones, Morgan Thomas [Show all 18 contributors for this article] (2025). Mimir High Core-log-seismic Integration. Full text in Research Archive
• Planke, Sverre; Millett, John; Lebedeva-Ivanova, Nina N.; Bünz, Stefan; Jones, Morgan Thomas & Myklebust, R. (2024). Cretaceous and Paleogene Source Rock Potential on the Norwegian Atlantic Margin. doi: 10.3997/2214-4609.2024101502. Full text in Research Archive
• Svensen, Henrik Hovland; Callegaro, Sara; Kjøll, Hans Jørgen; Midtkandal, Ivar; Whattam, Jack William & Dalslåen, Bjørgunn Heggem [Show all 10 contributors for this article] (2024). Rhomb porphyry lavas from the Oslo Rift revisited: New insights from construction-related boreholes and cores. Full text in Research Archive
• Dalslåen, Bjørgunn Heggem; Planke, Sverre; Svensen, Henrik Hovland & Kirkeby, Terje Rogvi (2024). Conquering the sub-surface: Taking on the Oslo Rift lava pile and infrastructure development. Full text in Research Archive
• Jakobsen, Frank Werner; Winsborrow, Monica Caroline Mackay; Nielsen, Tove; Böttner, Christoph; López-Quirós, Adrián & Planke, Sverre [Show all 9 contributors for this article] (2024). Late Miocene onset for shelf glaciation on NE Greenland. Full text in Research Archive
• Planke, Sverre; Berndt, Christian; Bünz, Stefan; Huismans, Ritske Sipke; Faleide, Jan Inge & Svensen, Henrik Hovland [Show all 11 contributors for this article] (2024). Understanding Volcanic Rifted Margins and Paleoenvironment by Scientific Drilling in the NE Atlantic. Full text in Research Archive
• Planke, Sverre (2024). Potensialet for permanent CO2 lagring i vulkanske bergarter i Norskehavet. Full text in Research Archive
• Planke, Sverre; Millett, John M.; Lebedeva-Ivanova, Nina; Bünz, Stefan; Jones, Morgan Thomas & Myklebust, Reidun (2024). Cretaceous and Paleogene Source Rock Potential on the Norwegian Atlantic Margin. Full text in Research Archive
• Stokke, Henrik Henriksen; Planke, Sverre; Lebedeva-Ivanova, Nina & Duarte, Henrique (2024). New Insights to Glaciogenic Sequences Using Ultra-High-Resolution 3D and 2D Seismic in Mjøsa, Norway. 85th EAGE Annual Conference & Exhibition. p. 1–5. doi: 10.3997/2214-4609.2024101579. Full text in Research Archive
• Planke, Sverre (2024). Drilling volcanic rifted margins to understand large igneous provinces and associated global warming. Full text in Research Archive
• Stokke, Henrik Henriksen; Planke, Sverre; Lebedeva-Ivanova, Nina & Duarte, Henrique (2024). New Insights to Glaciogenic Sequences Using Ultra-High-Resolution 3D and 2D Seismic in Mjøsa, Norway. Full text in Research Archive
• Jones, Morgan; Rooney, Alan; Zuchuat, Valentin; Turner, Holly; Frieling, Joost & Mather, Tamsin [Show all 14 contributors for this article] (2024). Volcanic proxies from the northern Pangean margin across the Permian-Triassic boundary: Evidence of intermittent Siberian Traps activity. Full text in Research Archive
• Zastrozhnov, Dmitrii; Planke, Sverre; Millett, John; Horota, Rafael Kenji; Kontny, Agnes M. & Senger, Kim [Show all 12 contributors for this article] (2024). Quaternary Magmatism in NW Svalbard: Refining the Architecture and Evolution of Sverrefjellet Volcano. EGU General Assembly Conference Abstracts. doi: 10.5194/egusphere-egu24-6844. Full text in Research Archive
• Zastrozhnov, Dmitrii; Planke, Sverre; Lebedeva-Ivanova, Nina N.; Millett, John M.; Bünz, Stefan & Binde, Cornelia Mentzoni [Show all 12 contributors for this article] (2024). The Tectonomagmatic Development of the Vøring Marginal High, Norwegian Sea: Core-log-seismic Integration of the IODP Expedition 396 Boreholes U1571 and 1572. Full text in Research Archive
• Tugend, Julie; Mohn, Geoffroy; Kusznir, Nick; Planke, Sverre; Berndt, Christian & Manton, Ben [Show all 8 contributors for this article] (2024). Palaeobathymetry of the Mid-Norwegian volcanic margin during continental breakup and paleoclimate implications. EGU General Assembly Conference Abstracts. Full text in Research Archive
• Augland, Lars Eivind; Midtkandal, Ivar; Svensen, Henrik Hovland & Planke, Sverre (2024). Detrital zircons in reworked tephra deposits – a proxy for contourites? Full text in Research Archive
• Nygaard, Madeleine Skov; Planke, Sverre; Berndt, Christian; Zastrozhnov, Dmitry; Faleide, Jan Inge & Jones, Morgan Thomas [Show all 24 contributors for this article] (2024). PALMAR – Paleogene Basin Development on the Vøring and Møre Margins. Full text in Research Archive
• Nygaard, Madeleine Skov; Planke, Sverre; Berndt, Christian; Zastrozhnov, Dmitry; Faleide, Jan Inge & Jones, Morgan Thomas [Show all 24 contributors for this article] (2024). IODP Exp. 396 Drilling and High-Resolution 3D Seismic on the Mimir High. Full text in Research Archive
• Nygaard, Madeleine Skov; Planke, Sverre; Berndt, Christian; Zastrozhnov, Dmitry; Faleide, Jan Inge & Jones, Morgan Thomas [Show all 11 contributors for this article] (2024). Characterization of the Vøring Transform Margin by IODP Exp. 396 Drilling and High-Resolution 3D Seismic on the Mimir High. Full text in Research Archive
• Tegner, Christian; Andersen, Torgeir Bjørge; Kjøll, Hans Jørgen; Brown, Eric L.; Graham-Hagen, Peter & Corfu, Fernando [Show all 8 contributors for this article] (2024). Dyke Complexes of the Scandinavian Caledonides. Full text in Research Archive Show summary

  Dyke Complexes of the Scandinavian Caledonides Christian Tegnera, Torgeir B. Andersenb, Hans Jørgen Kjøllb, Eric L. Browna, Graham Hagen-Peterc, Fernando Corfub, Sverre Plankeb, and Trond H. Torsvikb aDepartment of Geoscience, Aarhus University, Denmark, christian.tegner@geo.au.dk; bDepartment of Geosciences, University of Oslo, Norway; cEarth Sciences, Vrije Universiteit Amsterdam, Netherlands Dyke complexes (c. 615 – 560 Ma) exposed in the Scandinavian Caledonides are part of the Central Iapetus Magmatic Province, a large igneous province related to the opening of the Iapetus Ocean and an earlier phase of the North Atlantic Wilson Cycle. These include a >1000 km long dyke complex preserved in the Särv, Seve and Corrovarre nappes (Andréasson et al., 1998; Hollocher et al., 2007; Tegner et al., 2019) and dykes of the Seiland Igneous Province preserved in the Kalak nappe (Robins and Takla, 1979; Reginiussen et al., 1995). The compositions of the >1000 km long dyke complex is mainly tholeiitic and displays lateral geochemical zonation from enriched to depleted basaltic compositions from south to north. In addition, the central part of this dyke complex (in Trøndelag, Norway and Jämtland, Sweden) displays alkali basalt compositions. In contrast, the dykes of the Seiland Igneous Province are entirely composed of alkali basalts including ankaramite, picrite and lamprophyres. In this talk we will review the geochemical details of the basaltic magmas in the Scandinavian dyke complexes and discuss their origin from heterogenous and most likely multiple mantle plumes, and from enriched subcontinental lithospheric mantle. References Andréasson, P.G., Svenningsen, O.M., Albrecht, L. (1998). Dawn of Phanerozoic orogeny in the North Atlantic tract; Evidence from the Seve-Kalak Superterrane, Scandinavian Caledonides. Journal of the Geological Society of Sweden GFF 120, 159–172. doi:10.1080/11035899801202159 Hollocher, K., Robinson, P., Walsh, E., Terry, M.P. (2007). The Neoproterozoic Ottfjället dike swarm of the Middle Allochthon, traced geochemically into the Scandian Hinterland, Western Gneiss Region, Norway. American Journal of Science 307, 901–953. doi:10.2475/06.2007.02 Reginiussen, H., Ravna, E.J.K., Berglund, K. (1995). Mafic Dykes from Øksfjord, Seiland Igneous Province, northern Norway: geochemistry and palaeotectonic significance. Geological Magazine 132, 667–681. Robins, B., Takla, M.H. (1979). Geology and geochemistry of a metamorphosed picrite-ankaramite dyke suite from the Seiland province, northern Norway. Norsk Geologisk Tidsskrift 59, 67-95. Tegner, C., Andersen, T.B., Kjøll, H.J., Brown, E.L., Hagen-Peter, G., Corfu, F., Planke, S., and Torsvik, T.H. (2019). A mantle plume origin for the Scandinavian Dyke Complex: a “piercing point” for 615 Ma plate reconstruction of Baltica? Geochemistry, Geophysics, Geosystems 20, 1075-1094. doi:10.1029/2018GC007941

• Minakov, Alexander; Smirnov, Maxim; Senger, Kim; Betlem, Peter; Faleide, Jan Inge & Helland-Hansen, Anniken [Show all 14 contributors for this article] (2024). 3D magnetotelluric survey of a Miocene-Quaternary volcanic province in NW Svalbard. Full text in Research Archive
• Svensen, Henrik Hovland; John, Timm; Polozov, A.; Callegaro, Sara; Jones, Morgan Thomas & Newton, Robert [Show all 8 contributors for this article] (2023). Carbon, sulphur, and mercury geochemistry in a crater lake in the Siberian Traps. Full text in Research Archive
• Callegaro, Sara; Svensen, Henrik Hovland; Heimdal, Thea Hatlen; Guarino, Vincenza; Deegan, Frances M. & Jerram, Dougal Alexander [Show all 8 contributors for this article] (2023). Dolerite sills from the Siberian Traps (Tunguska basin, Russia) bear evidence of halogens mobilization from evaporitic host rocks. Full text in Research Archive
• Callegaro, Sara; Svensen, Henrik Hovland; Heimdal, Thea Hatlen; Deegan, Frances M.; Jerram, Dougal Alexander & Polozov, Alexander [Show all 7 contributors for this article] (2023). Magma-evaporite interaction in doleritic sills from the Siberian Traps: insights from whole-rock and mineral data. Full text in Research Archive
• Jakobsen, Frank Werner; Nielsen, T.; Bellwald, Benjamin; Planke, Sverre; Laberg, Jan Sverre & Winsborrow, Monica (2023). Towards a better understanding of the glacial development of the NE Greenland margin. Full text in Research Archive
• Bellwald, Benjamin; Stokke, Henrik Henriksen; Winsborrow, Monica; Planke, Sverre; Sættem, J. & Lebedeva‐Ivanova, N. [Show all 10 contributors for this article] (2023). Structural and Fluid‐Migration Control on Hill‐Hole Pair Formation: Evidence from High‐Resolution 3D Seismic Data from the SW Barents Sea. Full text in Research Archive
• Planke, Sverre; Berndt, Christian; Zarikian, Carlos A. Alvarez; Bünz, Stefan; Zastrozhnov, Dmitrii & Lebedeva-Ivanova, Nina [Show all 10 contributors for this article] (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. Full text in Research Archive
• Planke, Sverre; Millett, John M.; Manton, Ben M.; Jerram, Dougal Alexander; Rossetti, Lucas & Myklebust, Reidun (2023). Exploring Brazilian Volcanic Basins for Hydrocarbons and Permanent Carbon Storage. Full text in Research Archive
• Planke, Sverre; Lebedeva-Ivanova, Nina; Bünz, Stefan; Binde, Cornelia Mentzoni; Berndt, Christian & Faleide, Jan Inge [Show all 11 contributors for this article] (2023). High-resolution core-log-seismic integration and igneous seismic geomorphology of IODP Expedition 396 sites on the mid-Norwegian margin. Full text in Research Archive
• Planke, Sverre; Christian, Berndt; Zarikian, Zarikian Alvarez; Huismans, Ritske Sipke; Bünz, Stefan & Faleide, Jan Inge [Show all 8 contributors for this article] (2023). Breakup Magmatism and Paleogene Paleoenvironment: Initial Results from IODP Expedition 396 on the Mid-Norwegian Continental Margin. Full text in Research Archive
• Planke, Sverre (2023). Hva skjer på Island nå? [Radio]. NRK Studio 2. Full text in Research Archive
• Zastrozhnov, Dmitrii; Planke, Sverre; Lebedeva-Ivanova, Nina N.; Millett, John M.; Bünz, Stefan & Binde, Cornelia Mentzoni [Show all 10 contributors for this article] (2023). The Paleogene Tectonomagmatic Development of the Vøring Marginal High, offshore mid-Norway. AGU Fall Meeting Abstr.. Full text in Research Archive
• Lebedeva-Ivanova, Nina N.; Planke, Sverre; Millett, John; Bünz, Stefan; Binde, Cornelia Mentzoni & Manton, Ben M. [Show all 10 contributors for this article] (2023). Terrestrial Early Eocene Volcanic Paleoenvironment of the Skoll High, Mid-Norwegian Margin, Based on New High-Resolution 3D Seismic Geomorphology. EGU General Assembly. Full text in Research Archive

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