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Sediment cores from the Mid-Norwegian Margin, IODP Expedition 396 recovered several glendonite (calcite) pseudomorphs after cold-water ikaite, CaCO3•6H2O, within sediments deposited during the Paleocene-Eocene Thermal Maximum hyperthermal and the early Eocene greenhouse. This presents an apparent climate paradox, since during this time interval, deep sea bottom water temperatures are not believed to have been lower than c. 10 °C anywhere on Earth, mostly much warmer (Meckler et al., 2022 and references therein), far above temperatures typical for natural ikaite formation (Vickers et al., 2022 and references therein). The glendonites are found in close association with ash horizons from the nearby North Atlantic large igneous province (NAIP), with some actually in the infill of a hydrothermal. This, coupled with the presence of glendonites in sediments of the same age from Svalbard and Denmark (Spielhagen and Tripati, 2009; Vickers et al., 2020), may point to volcanically-driven climate and environmental changes in this region, perhaps on temporal and spatial scales hitherto unresolved by global-scale datasets. Here, we present reconstructed ikaite crystallisation temperatures from clumped isotope palaeothermometry and biomarker sea surface and air temperature reconstructions from glendonite-bearing horizons in ash-rich sediments at four IODP Expedition 396 sites. We find that the glendonites indicate bottom water temperatures considerably lower than the majority of other localities so far studied for this time interval (0 – 10 °C). The biomarker signals are harder to interpret, but may indicate sea surface and air temperatures significantly lower than many other studies across this time interval. We discuss possible causes and mechanisms for this cooling, and the conditions driving ikaite growth, focussing on whether these both may be linked to NAIP volcanism.

Extensive magmatism during the NE Atlantic break-up generated about 6-10 million cubic kilometers of magma in the Paleogene. Magmatic degassing and explosive discharge of thermogenic gases by contact metamorphism is implicated in triggering the Paleocene-Eocene Thermal Maximum (PETM; 56 Ma). In 2022, the CAGE22-5 research cruise collected high-resolution seismic, sub-bottom profiler, and multibeam data across the central and northern Vøring Plateau to tie IODP Expedition 396 Sites U1571 to U1574. One high-resolution P-Cable 3D seismic cube (10.3 by 1.8 km) was collected on the Skoll High, covering both sites U1571 and U1572. The data were fast-track processed with a bin size of 6.1 x 6.1 m. Four Cenozoic sedimentary horizons and the Top Basalt horizon were subsequently interpreted, followed by horizon attribute analyses. The Top Basalt horizon reveals unprecedented details of the nature of the volcanic paleosurface. A faulted and eroded lava horizon characterizes the southeastern part of the cube at 150-250 m below sea floor (bsf) around the U1571 site location. In contrast, in the northwestern part of the cube, the Top Basalt attribute maps reveal a pitted surface and lobate structures with linear ridges with characteristic inter-ridge spacings of a few tens of meters. The pitted basalt surface is mapped in an area of about 5.5 km2 at depths of 250-350 m bsf and drilled by Site U1572. About 270 individual pits have been mapped with radius ranging from about six meters, within the horizontal resolution of the data, to about 50 meters with a mean radius of c. 16 meters. The holes are interpreted as rootless cones, which comprise volcanic craters resulting from the explosive reaction between lava flows which flow over water-saturated sediments. The dimensions of the rootless cones in the Skoll 3D survey are comparable with the field analogue of rootless cones mapped in the Myvatn lake area of NE Iceland. Unlike at Myvatn and at other field analogues, the Skoll3D data allow unique 3D imaging of the rootless cones revealing internal structures and geometries including the base of the cone structures. The cone depths vary from meters to a few tens of meters. The lobate structures are interpreted as separate subaerial lava flows with compressional ridges. These lava flows are similar to outcrop analogue lava flows and compressional ridges imaged by elevation model ISN2016 with a 2x2 m resolution near the Myvatn lake. In conclusion, the interpreted patterns of the basaltic pitted surface within the Skoll3D suggest a wet terrestrial paleoenvironment during effusive volcanism. Unlike in the eastern faulted area of the survey, the extremely well imaged pitted basalt surface of the Skoll3D area did not experience significant erosion, suggesting rapid subsidence and drowning of the paleo-land surface in a low-energy coastal environment. This study demonstrates the unprecedented detail that is possible when high resolution 3D seismic data acquisition is applied to buried volcanic landscapes and opens the potential for unique associated insights in the Northeast Atlantic and further afield.

In the Siberian Traps Large igneous province (LIP), the emplacement of magma in sedimentary strata led to explosive release of volatiles and the formation of large pipe structures with explosion craters. Of the hundreds of pipes present, several still have preserved crater lake sediments, representing the only known end-Permian sedimentary archive proximal to the Siberian Traps. Here we present new data from a core from the best studied crater lake section, the October pipe/crater located west of Bratsk in East Siberia. The S26 core contains 505 meters of sediments and in order to investigate the geochemical processes in the lake and the possible role of brine influx from the breccia pipe below, we have analysed carbon isotopes, the mercury content, δ34S and δ56Fe in pyrite and δ56Fe in magnetite, from the breccia pipe and crater sediments. In addition, reference samples from two other breccia pipes and relevant sedimentary strata from the Tunguska Basin were analysed for comparison. Our previous work has shown that the lake was saline, stratified and anoxic/euxinic, with up to 4 wt.% TOC, and abundant framboidal pyrite. The sediments are dominated by sandstone and siltstone, sourced from the material ejected during the pipe formation, and have not experienced heating above ca. 50 °C. The basal deposits are coarse and contain reworked magnetite-apatite ore that originally precipitated from hydrothermal fluids within the upper parts of the pipe. The sediments are calcite-cemented and the volcanic minerals altered to clays and zeolites, with occasional oxidized zones showing that the water level fluctuated, in accordance with rapid subsidence resulting from dissolution of deeper-seated Cambrian evaporites. New results show a marked shift in the isotope systems from the breccia pipe and into the basal lake deposits. The δ34S shifts from background sedimentary values (+20-30‰) in the pipe breccia, to -7-0‰ in the lower half of the lake sediments followed by an increase to +20 ‰ towards the top of the lake. The trend is evident in the δ56Fe in magnetite as well, with a 0.4 ‰ negative shift from the breccia and into the lake sediments, followed by an upward increase in the stratigraphy. We suggest that basinal brines rich in iron and sulphate were partly reduced in the stratified lake, leading to pyrite precipitation and isotope fractionation. The data shows the interplay between lake processes and fluid seepage from a hydrothermal system, making these deposits unique for understanding the consequences of LIP formation.

Intrusion of magma into sedimentary basins leads to devolatilization of the host rock in contact metamorphic aureoles. Hydrothermal vent complexes are formed by fracturing the overburden sediments if sufficient overpressure is developed in the aureoles, releasing hot fluids and gases into the hydrosphere and atmosphere. We have mapped the structure and distribution of hydrothermal vent complexes using extensive 3D seismic reflection surveys (c. 40,000 km2) in the Møre and Vøring basins offshore mid-Norway by a combination of seismic horizon and attribute mapping. The seismic horizons have been tied to exploration wells to constrain the timing of their formation. A shallowly buried vent complex, the Modgunn Vent, was subsequently imaged by high-resolution P-Cable 3D seismic data collected using the R/V Helmer Hansen. The upper part of this vent complex was recently drilled by five holes during IODP Expedition 396. In total, more than a thousand hydrothermal vent complexes have been identified in the two basins. A typical vent complex has a diameter of between a few hundred meters and five kilometers and extends from the tip of a sill intrusion to the paleosurface. The upper part of the vent complexes are commonly eye-shaped, where the lower surface represents the base of a crater and the upper dome-shaped surface represents the top of the crater infill. Overlying reflections are sub-parallel to the upper vent surface, locally associated with discontinuous high-amplitude reflections and minor faulting. The chimney-shaped lower part of the vent complexes are characterized by disrupted reflections, sometimes including bulbous-shaped transparent bodies with high-amplitude reflections at the top and base. Surrounding reflections are often dipping towards the center of the chimneys. The structure of the vent complexes suggest they were dominantly formed by erupting fluids and sediments during the Paleocene-Eocene Thermal Maximum (PETM), about 56 million years ago. The craters were subsequently rapidly infilled by sediments, and later inverted forming domes above the craters. High-amplitude discontinuous reflections above some vent complexes are interpreted as evidence of long-term fluid flow, sometimes lasting until recent times.

Magnetotellurics (MT) image the Earth’s electrical resistivity down to the mantle but is rarely used for investigation of offshore rifted margins. In such setting, the stretched lithosphere is altered by distinct tectono-thermal processes such as partial melt, hydration, or chemical alteration. However, lower crustal and upper mantle often display similar seismic velocities, density, and magnetic properties. Integration of resistivity models from MT data can lift this ambiguity in a hyper-extended rift system. In this project, we use an extensive marine MT database consisting of 337 receivers located along seven regional transects, emanating from ~70 000 km2 of 3-D CSEM surveys acquired for hydrocarbon exploration in the SW Barents Sea. 3D inversion of long period, marine MT data (1 – 3000 s) is performed on 104 receivers located along two, ~300 km long transects located over the Bjørnøya Basin, located ~300 km offshore northern Norway. We also apply 1D Bayesian inversion to a selection of receivers as an alternative to the deterministic approach for a more comprehensive exploration of the solution space.The resolving power of MT data is assessed with synthetic tests in an archetypal rift system where ample crustal thickness variation occurs. The results highlight that our MT data sense the transition from necking to hyper-extended domain where the crust (

Continental breakup in the NE Atlantic was associated with mafic magmatism recorded by basalt flows, volcanogenic sediments, magmatic underplates, and intrusive sheet complexes in the nearby sedimentary basins and continental crust. The voluminous magmatism is concomitant with the global hot-house climate in the Paleogene, and the injection of magma into organic-rich sedimentary basins is a proposed mechanism for triggering short-term global warming during the Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma). IODP Expedition 396 drilled 21 holes along three transects on the mid-Norwegian continental margin to sample 1) Paleogene sediments along the Vøring Transform Margin and in hydrothermal vent complexes, and 2) basalt deposits from the Vøring Marginal High into the oceanic Lofoten Basin. A total of 2 km of core were recovered, including more than 350 m of basalt, 15 m of granite, and 900 m of late Paleocene to early Eocene sediments. Wireline logging data were recorded in eight holes. All the sites were located on industry-standard 2D and 3D seismic data. In addition, high-resolution seismic data were acquired in 2020 and 2022 over all the 21 Expedition 396 boreholes and 5 legacy ODP/DSDP sites using R/V Helmer Hansen. The seismic surveys included three P-Cable 3D cubes covering the 14 boreholes on the Modgunn (5), Mimir (5), and Skoll (4) transects. A comprehensive core-log-seismic integration program is ongoing for each site, based on an integration of high-resolution biostratigraphy, core and log based petrophysical data, and seismic modelling. The expedition recovered the first sub-basalt cores on the mid-Norwegian continental margin, recovering 15 m of granite. It furthermore collected the first samples from an Outer High at Site U1574, recovering both pillow basalts and hyaloclastites. These cores documented a shallow marine depositional environment of the emergent Eldhø volcano located near the foot of the Vøring Plateau. Finally, we drilled five holes through the upper part of a hydrothermal vent complex with a very expanded Paleocene-Eocene Thermal Maximum (PETM) interval dominated by biogenic ooze and volcanic ash deposits, documenting the temporal correlation of intrusive breakup magmatism in the Vøring Basin and a major hypothermal event. Collectively, the Expedition 396 sample archive offers unprecedented insight into tectonomagmatic processes in the NE Atlantic, including links to both rapid and long-term climate variation in the Paleogene.

The NE Canada Rifted Margin (NCRM) Composite Tectono-Sedimentary Element (CTSE) developed during a long and complex history that produced two tectono-sedimentary elements (TSEs): (1) the pre-rift TSE of pre-Cretaceous age; and (2) the synrift TSE of Early Cretaceous–Paleocene age. The pre-rift TSE includes the oldest and most poorly known offshore sedimentary accumulations that mainly evolved in a cratonic setting. In contrast, Cretaceous–lower Paleocene sedimentary basins of the synrift TSE are known from several wells, seismic data, outcrops and seabed samples, and their extent and distribution are mapped in most parts of the margin. The synrift TSE is the most prospective part of the margin, and hydrocarbon shows have been documented in some wells and offshore seeps studies. This review provides insights into the Paleozoic–Cenozoic evolution of the NE Canada rifted margin in the Labrador Sea, Davis Strait and Baffin Bay. In this context, we discuss structural inheritance and rift development, and account for confirmed and potential hydrocarbon systems and plays.

There is a temporal correlation between the peak activity of the North Atlantic Igneous Province (NAIP) and the Paleocene–Eocene Thermal Maximum (PETM), suggesting that the NAIP may have initiated and/or prolonged this extreme warming event. However, corroborating a causal relationship is hampered by a scarcity of expanded sedimentary records that contain both climatic and volcanic proxies. One locality hosting such a record is Fur Island in Denmark, where an expanded pre- to post-PETM succession containing hundreds of NAIP ash layers is exceptionally well preserved. We compiled a range of environmental proxies, including mercury (Hg) anomalies, paleotemperature proxies, and lithium (Li) and osmium (Os) isotopes, to trace NAIP activity, hydrological changes, weathering, and seawater connectivity across this interval. Volcanic proxies suggest that NAIP activity was elevated before the PETM and appears to have peaked during the body of the δ13C excursion, but decreased considerably during the PETM recovery. This suggests that the acme in NAIP activity, dominated by flood basalt volcanism and thermogenic degassing from contact metamorphism, was likely confined to just ~200 kyr (ca. 56.0–55.8 Ma). The hundreds of thick basaltic ashes in the post-PETM strata likely represent a change from effusive to explosive activity, rather than an increase in NAIP activity. Detrital δ7Li values and clay abundances suggest that volcanic ash production increased basaltic reactive surface area, likely enhancing silicate weathering and atmospheric carbon sequestration in the early Eocene. Signals in lipid biomarkers and Os isotopes, traditionally used to trace paleotemperature and weathering changes, are used here to track seaway connectivity. These proxies indicate that the North Sea was rapidly cut off from the North Atlantic in under 12 kyr during the PETM recovery due to NAIP thermal uplift. Our findings reinforce the hypothesis that the emplacement of the NAIP had a profound and complex impact on Paleocene–Eocene climate, both directly through volcanic and thermogenic degassing, and indirectly by driving regional uplift and changing seaway connectivity.

The Paleocene-Eocene Thermal Maximum (PETM) around 56 Ma was associated with 5-6 °C global warming, resulting from massive carbon release into the ocean–atmosphere system. One potential driver of hyperthermal conditions was the North Atlantic Igneous Province (NAIP), as both volcanic degassing and thermogenic volatile release during contact metamorphism during its emplacement were large potential emitters of carbon. Despite a broad temporal correlation between NAIP activity and the PETM, the exact relationship is obscured by multiple climate forcings, imprecise geochronological data, uncertainties in the timing and magnitude of volatile fluxes from volcanic and thermogenic sources, and limited availability from crucial NAIP localities that could constrain these unknowns. Here we present new seismic and borehole data for the Modgunn hydrothermal vent complex in the Northeast Atlantic (IODP Sites U1567-U1568). Stable carbon isotope stratigraphy and dinoflagellate cyst biostratigraphy reveal a negative carbon isotope excursion coincident with the appearance of Apectodinium augustum in the vent crater infill. Modern examples of submarine explosion craters suggest they have filled in within decades to centuries, so the preservation of the PETM onset within the Modgunn vent suggests an extremely close temporal correlation between the crate formation and the onset of hyperthermal conditions. Furthermore, the majority of the craters across the entire NAIP are likely to have vented in very shallow water, implying that the vast majority of emitted CO2 and CH4 gases directly entered the atmosphere during eruptions. These findings add considerable weight to the hypothesis that thermogenic degassing aided the initiation of the PETM.

The overall goal of this expedition was the acquisition of geophysical data on the Vøring Plateau and the southernmost part of the Lofoten Basin to improve the understanding of the subsurface structures and geological processes at four sites (U1571-U1574) where scientific drilling was recently successfully completed as a part of the the International Ocean Discovery Program (IODP) Expedition 396 The cruise may be known as: CAGE22_5

[Example of collonade and entablature cooling joints within a ponded lava of the Rosebank Field Upper Volcanics revealed by formation microimager log data alongside a field analogue example from the Isle of Staffa. , Abstract The Rosebank Field is located in the Faroe‐Shetland Basin and hosts hydrocarbons within siliciclastic sediments interlayered with volcanic packages of the Late Paleocene to Early Eocene aged Flett Formation. Within this study the volcanic sequences are investigated based on an integrated appraisal of available drill cuttings, sidewall cores, core and wireline logs including image log and geochemical logs from eight wells supported by 3D seismic data. The Rosebank lower (RLV), middle (RMV) and upper (RUV) volcanic sequences are inter‐layered with Colsay Member (C1–C4) fluvial to shallow marine siliciclastic intervals. A comprehensive cross‐field borehole based lithofacies interpretation is presented characterising simple, compound and ponded effusive lava flow facies along with pillow lavas, invasive lava flows, volcaniclastic sediments and complex lava–sediment interactions. Geochemical analyses of core, sidewall core, and hand‐picked cuttings spanning the field reveal separate high‐titanium (RHT) and relatively lower‐titanium (RLT) basaltic magma suites. These compositions can be identified and correlated across much of the field utilising geochemical logging data which, in combination with the geochemical analyses, reveals a two‐part stratigraphic sub‐division of each of the RLV, RMV and RUV. Geochemical logging data is also used to define a volcanic proxy (Fe/10+Ti) which utilises the elevated iron (Fe) and titanium (Ti) within all effusive and volcaniclastic basaltic lithologies to differentiate siliciclastic from volcaniclastic sediments where other logging parameters overlap. By comparing the borehole analyses with seismic data, a localised eruptive vent is interpreted within the north of the field. Finally, a cross‐field volcanic model is presented and compared with relevant global field analogues, providing a constrained spatial framework for sub‐surface modelling of inter‐volcanic sequences.]

Incised drainage systems can provide a record of the timing, duration and magnitude of ancient vertical crustal motion. The NE Atlantic underwent rapid uplift at c. 56 Ma, resulting in widespread incision and the formation of Paleogene unconformities across the Faroe–Shetland Basin. We used 3D seismic data to map a newly identified incised drainage system in the northern Faroe–Shetland Basin that formed during this period of uplift and compared it with similar incision surfaces in the region. The c. 30 km × 50 km erosional surface is a composite feature, comprising the Upper Thanetian Unconformity, which was rejuvenated and eroded by the younger Flett Unconformity, and records prolonged regional uplift during the late Thanetian–earliest Ypresian punctuated by a phase of subsidence. The drainage system was influenced by igneous intrusions, resulting in the diversion of channels around forced fold structures. Several preserved palaeoshorelines occur close to the basinward limit of the incision surface, recording progressive back-stepping of the shoreline and marine transgression during early Ypresian subsidence. The drainage system may have supplied ‘clean’ sand, eroded from the North Shetland Platform, to the Flett Sub-basin, with the potential to form high-quality reservoir units. Such sands may have been concentrated along shorelines coeval with the drainage system, but potentially were also delivered further out into the basin.

While carbon capture and storage (CCS) has been recognized as a major enabler to reduce the amount of CO2 released into the atmosphere, the industry is still in its infancy. Both new technology and cost-effective approaches will be necessary if CCS is to live up to its potential to reduce global warming in the decades to come. Energy data companies such as TGS can, with help from partners, work on concepts and technologies that will be key for the CCS market, and current products made for the oil and gas market can potentially be repurposed for use in CCS. Technologies are also being developed for the 4D monitoring of stored carbon in the decades to come. Furthermore, the storage of carbon within basalt rocks has been proposed by TGS as an alternative to the sedimentary rocks targeted by most CCS endeavours today.

The nature and growth of magmatic plumbing systems are of fundamental importance to igneous geology. Traditionally, magma chambers have been viewed as rapidly emplaced bodies of molten rock or partially crystallized “magma mush” connected to the surface by a narrow cylindrical conduit (referred to as the “balloon-and-straw” model). Recent data suggest, however, that magma chambers beneath volcanoes are formed incrementally through amalgamation of smaller intrusions. Here we present the first high-resolution three-dimensional reconstruction of an ancient volcanic plumbing system as a large laccolithic complex. By integrating seismic reflection and gravity data, we show that the ∼200 km3 laccolith appears to have formed through partial amalgamation of smaller intrusions. The complex appears to have fed both surface volcanism and an extensive sill network beneath the volcanic edifice. Numerous sills are imaged within the volcanic conduit, indicating that magma stalled at various levels during its ascent. Our results reveal for the first time the entire multicomponent plumbing system within a large ancient shield volcano.

Trough mouth fans comprise the largest sediment deposits along glaciated margins, and record Pleistocene climate changes on a multi-decadal time scale. Here we present a model for the formation of the North Sea Fan derived from detailed horizon and attribute interpretations of high-resolution processed 3D seismic reflection data. The interpretation shows that stacked channel-levee systems form up to 400 m thick sedimentary sequences. The channels are elongated and can be traced from the shelf edge towards the deep basin for distances of >150 km, and document long-distance sediment transport in completely disintegrated water-rich turbidite flows. Downslope sediment transport was a continuous process during shelf-edge glaciations, reaching accumulation rates of 100 m/kyr. Our data highlight that exceptionally large volumes of meltwater may discharge to the slopes of trough mouth fans and trigger erosive turbidite flows. We conclude that freshwater supply is likely an underestimated factor for sedimentary processes during glacial cycles., Trough mouth fans are created via repeated glacigenic sediment transport from ice sheets. Here the authors use 3D seismic reflection data to present a formation model for the North Sea Fan and find that exceptionally large volumes of meltwater may mean that freshwater supply is underestimated during glacial cycles.

This paper presents major, trace element and Sr-Nd isotope data on two large, east-west trending dolerite dykes in the southeastern part of the Karoo Basin, the South Gap (155 km long, ≤275 m wide) and the North Gap (150 km long, ≤190 m wide) dykes. The Gap dykes represent a rare case in the Karoo Large Igneous Province (LIP) where low-Ti (Gap1

The NE Atlantic volcanic rifted margins include vast underexplored basin areas neighbouring mature petroleum-producing regions. We appraise the cross-border prospectivity of the outer and central Faroe–Shetland, Møre and southern Vøring basins and present insights from extensive new 3D seismic surveys. Regional seismic surfaces are used to compile a cross-border seismic profile highlighting key discoveries from the UK Rosebank field in the SW to the Norwegian Ormen Lange field in the NE. Cretaceous to Paleocene reservoirs remain the main exploration focus seaward of the platform areas, and the presence of several large untested structures presents important exploration targets in the mid-Norway region. Improved imaging of the areas affected by Paleogene igneous rocks reveals major untested sub-basalt structures including some regions on the marginal highs where the basalt cover has been entirely removed by erosion, revealing sub-basalt stratigraphy and structures with pre-Cretaceous potential prospectivity. The influence of igneous rocks on both discovered and prospective hydrocarbon systems is discussed. Neogene sand injectite fields and Quaternary glacial sand bodies are extremely well imaged in the Møre Basin, documenting shallow prospectivity supported by the presence of successful regional analogue plays. New 3D seismic data are revealing previously unseen prospectivity in frontier and underexplored regions.

Trough mouth fans comprise the largest sediment deposits along glaciated margins, and record Pleistocene climate changes on a multi-decadal time scale. Sedimentation related to climate warming in polar regions and new challenges associated with the energy transition highlight the urge for better knowledge of these depocenters. Here, we present sedimentation models for the two largest of these depocenters – the Bear Island Fan on the western Barents Sea margin and the North Sea Fan on the northern North Sea margin – which are analogues for large glacial fans along the Antarctic and Greenland margins. We use extensive high-quality 3D reflection seismic cubes (37,200 km2) as well as conventional 2D reflection seismic lines, and combine these datasets with lithological and geophysical borehole logs.The stratigraphy of trough mouth fans is dominated by contourites, glacigenic debris flows, meltwater turbidites, and megaslides, which together result in a thickness exceeding 2 km. Neogene to early Quaternary-age contourites are characterized by continuous and high-amplitude reflections in the seismic data. The contourites of the late Quaternary, in contrast, have a more transparent seismic facies, and onlap the escarpments shaped by the megaslides. The lithology of the contourites varies from fine clays to coarse sands. Meltwater turbidites are identified as high-amplitude reflections characterized by 4-100 m deep channels and sourced from multiple regions along the paleo-shelf break. The well-connected turbidite channels are 90-2100 m wide, and can be traced for distances of >100 km. These channels are both deeper and wider in the North Sea Fan compared to the Bear Island Fan. The lithology of these deposits has yet to be cored. Glacigenic debris flows are transparent packages of sediments, with a lens-shaped expression in the seismic profiles and lobe-shaped geomorphology in planar view. The grain size of glacigenic debris flows is typically more mud-dominated than for contourites, but glacigenic debris flows do include sandy beds at selected intervals. Glacigenic debris flows are more dominant in the high-latitude Bear Island Fan compared to the mid-latitude North Sea Fan. Megaslides consist of high-amplitude, deformed sediment that is constrained by steep headwalls and sidewalls. The megaslides within these two trough mouth fans have mainly occurred since the Late Pleistocene and fail along contouritic basal layers.The contourites were fed by fluvial systems on the East Shetland Platform and the Norwegian mainland, and are, in turn, often trapped by megaslide escarpments or deeper structural elements. The rapid glacial deposition of debris flows and turbidites delivered large sediment volumes to gently-dipping slopes, which then failed as megaslides. Trough mouth fans are excellent depocenters to study the interaction between along-slope and down-slope processes in high-resolution, both in space and time. We suggest that contourites are most active during interglacial periods, while turbidites and debris flows are more common during glacial periods. The timing of the megaslides, however, still includes large uncertainties. Meltwater contribution seems to be a more dominant factor for sedimentary processes in mid-latitude glacial fans than in their high-latitude counterparts.

Trough mouth fans are important depocenters for glacial sedimentation in high latitude margins, recording sedimentological processes and their relationship with paleoclimatic fluctuations on short timescales - from decades to millennia. The volume of sediments accumulated in these fans varies significantly depending on the phase of the glacial cycle, with higher values typically reached during early retreats. The input of large volumes during short time intervals can potentially trigger submarine landslides and overpressure build-up, making the understanding of processes and proportions related to sedimentation in glaciated margins crucial, especially during periods of global warming. In this study we use high-quality 3D seismic cubes (vertical resolution of 2 m and bin size of 6.25 x 18.75 m) to delimitate different types of deposits on an area over 14000 km2 on the North Sea Trough Mouth Fan during a full glacial-interglacial cycle of the last glaciation (Weichselian). After mapping the corresponding top and base surfaces of each type of deposit their volumes were calculated using the mean thickness of the beds multiplied by their extent. The base of the studied package comprises a contourite body deposited on top of the Tampen Slide, whose failure is estimated to have happened around 130 ka ago. Next we have a thick (> 400 m) mixed package of debris flows and meltwater turbidites, with its rapid deposition happening during approximately 4 ka (~23 to 19 ka). The package is then completed with plume settling related to the full retreat of the ice stream. Although not completely interpreted due to limitations of the dataset extent and remobilization of a part of the fan by the Storegga Slide in the northern part, the last glacial cycle comprises a total of 7160 km3 of sediments, with more than half of it (4850 km3) originated from the downslope processes. The plumites and contourites comprise volumes of 1105 km3 and 1205 km3. This accounts to a significant variability of the magnitude of sediment volume coming into the sink per year, with the downslope deposits having over 100 times more sediment input and the plumites 5 times more when compared to the contourites. These results highlight the range of sediment volume that can be delivered in a glaciated margin depending on changes in processes and climatic fluctuations, which may also entail changes in the potential geohazards.

An appraisal of ancient Earth’s climate dynamics is crucial for understanding the modern climate system and predicting how this might change in the future. Major climate-shift events in the Earth’s past demonstrate the scale, duration and response of the climate system to various global and local climate stressors. More than 650 million years of deep-time paleoclimate changes are archived in the sedimentary succession of Svalbard; an archipelago located in the Norwegian High Arctic. The excellently outcropping geological successions of Svalbard date back to the Proterozoic, and record both temporal and spatial changing climatic and environmental conditions strongly linked to the northward continental drift of the archipelago from southern hemisphere in Precambrian to its present-day Polar latitudes.The oldest deposits that record major climatic events and associated environmental perturbations in Svalbard include tillites related to several Cryogenian glacial events and the overlying Ediacaran carbonates. The Lower Paleozoic succession documents episodes of marine biodiversification, including the Great Ordovician Biodiversification Event (GOBE), which is linked to cooling of previously warm tropical oceans. The arid to semi-arid climate of the Devonian promoted a terrestrial plant diversification. The Lower Carboniferous coal-bearing strata were deposited in humid and tropical climate settings prevailing in northern Pangea. The Upper Carboniferous-Lower Permian succession consists of interbedded carbonates, evaporites and red siliciclastics, including remains of paleokarst. The continued northward drift into subtropical latitudes promoted a change back to arid to semi-arid climates, occurring during the overall global icehouse conditions. During the Late Permian, marine sponges were occupying most of the ecological niches, leading to the deposition of weathering-resistant spiculites. But these ecosystems were rapidly and dramatically impacted by the End Permian Mass Extinction (EPME), which lasted well into the Early Triassic.By the Mesozoic, Svalbard was approaching mid-latitudes. The exposed in Svalbard deposits of Triassic mega-delta features evidence for a temperate or humid climate, indicated by thick coal beds that transitioned to an arid climatic environment at the end of the Triassic and Early Jurassic succession with caliche and calcareous soil profiles. The Lower Cretaceous strata (deposited at c. 66 °N) record several cold snaps despite the overall greenhouse climate characterizing the period and most notably the global crisis associated with the Aptian oceanic anoxic event 1a (OAE1a).By the Paleogene, Svalbard had reached Arctic latitudes, and as characterised by overall moderate to warm temperate climate, punctuated by warming episodes, including the Palaeocene–Eocene Thermal maximum (PETM). The Neogene cooling is missing from onshore records, but high-resolution glacial climate evidence exists offshore and from geomorphology and unconsolidated strata of Late Quaternary-Holocene age.In this contribution, we synthesize former and ongoing studies of deep-time paleoclimate in Svalbard and provide knowledge gaps to optimize the use of Svalbard as an archive for deep-time paleoclimate research. The exceptional exposures, accessibility, and completeness of the 650 million long sedimentary records makes Svalbard unique archive for deep-time paleoclimate research. In addition to Svalbard’s excellent outcrops, fully cored research and coal exploration boreholes provide an excellent foundation for further research with minimal environmental consequences.

About 252 million years ago, near the end of the Permian, the Earth experienced its most dramatic mass extinction, caused by magmatic intrusions and volcanic eruptions associated with the Siberian Traps Large Igneous Province. This led to catastrophic global climatic changes, impacts of which lasted well into the Early Triassic.Here, we summarise the results gathered from the study of sedimentary successions spread across the Barents Shelf that recorded the End Permian Mass Extinction (EPME) and its aftermaths across the Permian-Triassic boundary. Data and samples were collected from the Festningen section in western Spitsbergen; the DD-1 core and the associated river section in Deltadalen, central Spitsbergen; a core (7933/4-U-3) drilled by the Norwegian Petroleum Directorate offshore Kvitøya in northern Svalbard; and a core (7130/4-1; production licence 586) recovered from the Finnmark Platform in the Barents Sea. A series of state-of-the-art analyses were conducted on the collected material, including detailed facies analysis, organic and C-isotope geochemistry, mercury content, geochronology, high resolution XRF core scanning, petrography, ichnology, and palaeontology. Analyses were, where relevant, tied to the outcrops using digital outcrop models.Traditionally, the Permian-Triassic boundary in Svalbard (and across the High Arctic regions) was placed at the marked and rapid facies change at the top of the siliceous mudstones and spiculites of the Kapp Starostin Formation, which are overlain by soft, non-siliceous mudstones and siltstones of the Vardebukta and Vikinghøgda formations. This abrupt facies change, which also marks the collapse of sponges, occurs across a few centimetres. Given that the non-siliceous mudstones were definitely of Early Triassic age, based on ammonoid biostratigraphy, this lithostratigraphic boundary was believed to represent a lacuna or a hiatus of several million years, with the uppermost Permian strata absent from the sedimentary record.The base of the Triassic, however, is not defined by ammonoid biostratigraphy but by the conodont Hindeodus parvus, which was recently reported to occur a few meters above the lithostratigraphic boundary in the Deltadalen section. This means that the lithostratigraphic boundary is of Permian age. Additionally, our new data show that sedimentation was continuous across this lithostratigraphic boundary, corresponding to major environmental changes, potentially associated with a reorganisation of the basin(s) physiography.Furthermore, the 6-8 ‰ δ13Corg negative excursion associated with the EPME falls between the lithostratigraphic and the Permian-Triassic boundary at all measured sections. These negative carbon isotope excursions occur in intervals with numerous tephra layers, the lowest of which has been dated at 252.13 ± 0.62 Ma, potentially connecting the recorded changes to the Siberian Traps. The EPME is also corroborated by the very abrupt decline of trace fossil abundance and diversity, as anoxia extended from proximal and shallow water to deeper settings. Geochemical and ichnological data support the existence of multiple anoxic pulses, separated by very brief periods of enhanced oxygen levels. It took ca. 150 Kyr for life to recover after the EPME, based on sedimentation rate calculations. Data also suggest that the hinterland of the basin experienced a shift towards more arid climatic conditions and increased eutrophication.

The NE Atlantic conjugate volcanic rifted margins are characterized by extensive breakup-related magmatism recorded by basalt flows, volcanogenic sediments, magmatic underplates, and intrusive complexes in sedimentary basins and the crust. Onset of this voluminous magmatism is concomitant with the global hot-house climate in the Paleogene, and the injection of magma into organic-rich sedimentary basins is a proposed mechanism for triggering short-term global warming during the Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma).The aims of IODP Exp. 396 (August-September 2021) were to drill three transects on the mid-Norwegian continental margin to sample 1) hydrothermal vent complexes formed by eruption of hot fluids and sediments above sill intrusions (Modgunn Transect), 2) Paleogene sediments, with particular focus on the Paleocene-Eocene transition (Mimir Transect), and 3) basalt and sub-basalt sequences across the volcanic rifted margin and the initial oceanic crust (Basement Transect). A total of 21 boreholes were drilled, successfully coring all nine primary and one alternate sites. A comprehensive suite of wireline logs was collected in eight boreholes. Most of the sites were located on industry-standard 3D seismic reflection data, whereas additional high-resolution 2D and 3D P-Cable site survey data were acquired across six sites which were highly useful during the Mimir and Modgunn transect drilling. In total, more than 2000 m of core were recovered during 48 days of operations, including more than 350 m of basalt, 15 m of granite, and 900 m of late Paleocene to early Eocene sediments. Drilling was done using a combination of RCB, XCB, and APC drill bits, commonly with half-advances (c. 5 m) to optimize core recovery. Particularly high recovery (almost 100%) was obtained by half-length APC coring of Eocene sediments in two holes on the outer Vøring Margin, whereas basaltic basement recovery was above 60% in seven holes.Expedition 396 probed the key elements of a typical volcanic rifted margin and the associated sedimentary archive. Of particular importance is the Modgunn Transect, where we drilled five holes through the upper part of a hydrothermal vent complex with a very expanded Paleocene-Eocene Thermal Maximum (PETM) interval dominated by biogenic ooze and volcanic ash deposits. The expedition also recovered an unprecedented suite of basalt cores across a volcanic rifted margin, including both subaerial and deep marine sheet flows with inter-lava sediments and spectacular shallow marine pillow basalts and hyaloclastites, as well as high-resolution interstitial water samples to assess sediment diagenesis and fluid migration in the region. Lastly, we recovered the first cores of sub-basalt granitic igneous rocks and upper Paleocene sediments along the mid-Norwegian continental margin. Collectively, this unique sample archive offers unprecedented insight on tectonomagmatic processes in the NE Atlantic, and links to rapid climate evolution across the Cenozoic.

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

Summary Magnetotelluric (MT) data allow for electrical resistivity probing of the Earth's subsurface. Integration of resistivity models in passive margin studies could help disambiguate non-unique interpretations of crustal composition derived from seismic and potential field data, a recurrent issue in the distal domain. In this contribution, we present the first marine MT data in the Barents Sea, derived from industrial controlled-source electromagnetic (CSEM) surveys. We characterize data quality, dimensionality, depth penetration and elaborate an analysis strategy. The extensive MT database consists of 337 receivers located along 7 regional transects, emanating from ∼70,000 km2 of 3D CSEM surveys acquired for hydrocarbon exploration from 2007 to 2019. High-quality MT data are extracted for periods ranging from 0.5 s to 5000 s. The data show no apparent contamination by the active source nor effects related to large time-gaps in data collection and variable solar activity. Along receiver profiles, abrupt lateral variations of apparent resistivity and phase trends coincide with major structural boundaries and underline the geological information contained in the data. Dimensionality analysis reveals a dichotomy between the western domain of the SW Barents Sea, dominated by a single N-S electromagnetic strike, and the eastern domain, with a two-fold, period-dependent strike. 35 receivers show 3D distortion caused by nearby bathymetric slopes, evidenced by elevated skew values. We delineate geographical areas where the 2D assumption is tenable and lay the foundation for future MT modelling strategies in the SW Barents Sea. We performed 2D MT inversion along one of the regional transects, a ∼220 km-long, E-W profile encompassing a major structural high and sedimentary basin approaching the continent-ocean transition. The resistivity model reveals low crustal resistivity values (1–10 Ω.m) beneath the deep sedimentary basins, in marked contrast with high resistivity values (1000–5000 Ω.m) of the thick crystalline crust on the structural high. We interpret this abrupt lateral resistivity variation as a rapid transition from a thick, dry continental crust to a hyperextended and hydrated crustal domain. Integration of resistivity with seismic velocity, density and magnetic susceptibility models may further refine these structural models and the underlying tectonic processes in the SW Barents Sea margin. Our methodology is applicable globally where 3D CSEM surveys are acquired and has a large potential for harvesting new knowledge on the electrical resistivity properties of the lithosphere.

[Abstract Hyaloclastites develop where lava interacts with water resulting in deposits that have a unique and often complex range of petrophysical properties. A combination of eruptive style and emplacement environment dictates the size, geometry and distribution of different hyaloclastite facies and their associated primary physical properties such as porosity, permeability and velocity. To date, links between the 3D facies variability within these systems and their petrophysical properties remain poorly understood. Hjorleifshofði in southern Iceland presents an exceptional outcrop exposure of an emergent hyaloclastite sequence >1 km wide by >200 m high and enables an investigation of the distribution of the hyaloclastite deposits at seismic scale. Within this study we present a photogrammetry‐based 3D model from part of this recent hyaloclastite delta and incorporate previous work by Watton et al. (Journal of Volcanology and Geothermal Research, 2013, 250, 19) to undertake detailed facies interpretation and quantification. Laboratory petrophysical analyses were performed on 34 core plugs cut from key field facies samples, including P‐ and S‐wave velocity, density, porosity and permeability at both ambient and confining pressure. Integration of the 3D model with the petrophysical data has enabled the production of pseudo‐wireline logs and property distribution maps which demonstrate the variability of physical properties within hyaloclastite sequences at outcrop to seismic scale. Through comparison of our data with examples of older buried hyaloclastite sequences we demonstrate that the wide‐ranging properties of young hyaloclastites become highly uniform in older sequences making their identification by remote geophysical methods for similar facies variations more challenging. Our study provides an improved understanding of the petrophysical property distribution within hyaloclastite sequences and forms a valuable step towards improving the understanding of similar subsurface sequences and their implications for imaging and fluid flow., We present a photogrammetry‐based 3D reconstruction of Hjorleifshofði in southern Iceland which provides an exceptional outcrop exposure of an emergent hyaloclastite sequence. By incorporating detailed facies interpretations and laboratory petrophysical analyses into the model, we have produced pseudo‐wireline logs and property distribution maps to demonstrate the variability of physical properties at seismic scale. Our study provides an improved understanding of the petrophysical property distribution within hyaloclastite sequences and forms a valuable step towards improving the understanding of similar subsurface sequences and their implications for imaging and fluid flow. ]

A comprehensive dataset is collated in a study on sediment transport, timing and basin physiography during the Early Cretaceous Period in the Boreal Basin (Barents Sea), one of the world’s largest and longest active epicontinental basins. Long-wavelength tectonic tilt related to the Early Cretaceous High Arctic Large Igneous Province (HALIP) set up a fluvial system that developed from a sediment source area in the NW, which flowed SE across the Svalbard archipelago, terminating in a low-accommodation shallow sea within the Bjarmeland Platform area of the present-day Barents Sea. The basin deepened to the SE with a ramp-like basin floor with gentle dip. Seismic data show sedimentary lobes with internal clinoform geometry that advanced from the NW. These lobes interfingered with, and were overlain by, another younger depositional system with similar lobes sourced from the NE. The integrated data allow mapping of architectural patterns that provide information on basin physiography and control factors on source-to-sink transport and depositional patterns within the giant epicontinental basin. The results highlight how low-gradient, low-accommodation sediment transport and deposition has taken place along proximal to distal profiles for several hundred kilometres, in response to subtle changes in base level and by intra-basinal highs and troughs. Long-distance correlation along depositional dip is therefore possible, but should be treated with caution to avoid misidentification of timelines for diachronous surfaces.

The Jan Mayen Microplate Complex (JMMC) in the NE Atlantic is interpreted to mostly consist of continental fragments with possible interstitial embryonic oceanic crust. A complex Cenozoic rifting history accompanied by extensive extrusive and intrusive volcanism have made the geological characterization of the JMMC challenging especially due to poor seismic imaging beneath the breakup basalt succession. The presence of continental crust in the JMMC is inferred by seismic and magnetic data, but ground truthing evidence have yet to be provided. Here, we present the results from a seafloor sampling campaign undertaken in 2011 on the Southern Jan Mayen Ridge complex. Seabed samples were recovered using a gravity corer and a dredge along a 1000 m high escarpment with a 19° slope. Sampling locations were selected based on the interpretation of seismic profiles that suggest the presence of possible pre-breakup successions outcropping along this steep escarpment. Results include a sequence of samples with age diagnostic palynomorph assemblages ranging from Permian/Triassic to Eocene, and including igneous samples related to the Early Eocene breakup volcanism. Importantly, the samples were retrieved from hard substrate in an erosional gully lacking overburden sediments and have ages arranged in younging upward sequential order, supporting their near in-situ position. The sampling results were integrated into a lithostratigraphic pseudo-well that can be used to constrain the evolution and breakup of the JMMC. Additionally, evidence for active migration of Jurassic sourced hydrocarbons comprise the first indication of a working hydrocarbon system, with important implications for the petroleum prospectivity of the Dreki area. Finally, these results confirm that the Southern Jan Mayen Ridge is indeed a sliver of continental crust.

Highlights • Determination of the tectonomagmatic evolution of the NW Atlantic • Mapping of the breakup-related magmatism using the vocanostratigraphy concept • Mapping of the magnetic and gravimetric crustal domain patterns and their boundaries using integrated SGM method • Analyses of seabed and onshore samples and field analogues work • New plate tectonic reconstruction for the NW Atlantic Abstract Passive margins are the locus of tectonic and magmatic processes leading to the formation of highly variable along-strike and conjugate margins structures. Using extensive new seismic, gravity, and magnetic datasets, complemented by seabed samples and field work, we investigate the tectonomagmatic evolution of the northwest (NW) Atlantic where breakup-related igneous rocks were emplaced during several Paleogene events associated with lithospheric stretching, continental breakup, and the formation of new oceanic basins. Interpretational methods include integrated seismic-gravity-magnetic (SGM) interpretation and seismic volcanostratigraphy. In addition, seabed and field samples were collected and analyzed to constrain the basin stratigraphy, hydrocarbon potential, and the geochronology and geochemistry of the volcanic sequences. Offshore, 2D seismic data reveal several Seaward Dipping Reflector (SDR) wedges and escarpments in the Labrador Sea, Davis Strait, and Baffin Bay. Onshore, eastward prograding foreset-bedded hyaloclastite delta deposits and overlying horizontal lava successions outcrop on Nuussuaq. These hyaloclastites and lava successions are world class analogues to the Lava Delta and Landward Flows volcanic seismic facies units identified offshore. Our mapping results document an aerial extent of the Paleogene breakup-related volcanics of 0.3 × 106 km2, with an estimated volume of 0.5–0.6 × 106 km3. Basalt samples recovered by dredging the Upernavik Escarpment have late Paleocene to/early Eocene ages, whereas the sedimentary samples provide an excellent seismic tie with the stratigraphy and the geology in this frontier area. From the integrated SGM interpretation, we identify a rapidly thinning crust and changes in top and intra-basement seismic reflection characteristics in the oceanic domain correlated with transition between different magnetic domains. The mapping results were subsequently integrated in a plate tectonic model. The plate tectonic reconstruction and basalt geochronology suggest that the majority of the volcanism in the NW Atlantic occurred between ~62 and ~58 Ma, associated with an increased spreading rate in the Labrador Sea, starting from the onset of the Selandian (~61.6 Ma). A change in the spreading direction during the Eocene (~56 Ma), synchronously with a shift of volcanic activity from the NW to the NE Atlantic, correspond to a northward drift of Greenland and the initiation of the Eurekan Orogeny. Finally, our interpretations reveal a complex rift configuration along the NW Atlantic conjugate margins both prior to and during breakup.

The origin of Large Igneous Provinces (LIPs) associated with continental breakup and the reconstruction of continents older than c. 320 million years (pre-Pangea) are contentious research problems. Here we study the petrology of a 615 - 590 Myr dolerite dyke complex that intruded rift-basins of the magma-rich margin of Baltica and now is exposed in the Scandinavian Caledonides. These dykes are part of the Central Iapetus Magmatic Province (CIMP), a LIP emplaced in Baltica and Laurentia during opening of the Caledonian Wilson Cycle. The >1000 km long dyke complex displays lateral geochemical zonation from enriched to depleted basaltic compositions from south to north. Geochemical modelling of major and trace elements shows these compositions are best explained by melting hot mantle 75-250°C above ambient mantle. Although the trace element modelling solutions are non- unique, the best explanation involves melting a laterally zoned mantle plume with enriched and depleted peridotite lithologies, similar to present-day Iceland and to the North Atlantic Igneous Province. The origin of CIMP appears to have involved several mantle plumes. This is best explained if rifting and breakup magmatism coincided with plume generation zones at the margins of a Large Low Shear-wave Velocity Province (LLSVP) at the core mantle boundary. If the LLSVPs are quasi-stationary back in time as suggested in recent geodynamic models, the CIMP provides a guide for reconstructing the paleogeography of Baltica and Laurentia 615 million years ago to the LLSVP now positioned under the Pacific Ocean. Our results provide a stimulus for using LIPs as piercing points for plate reconstructions.

Mafic sills of the Central Atlantic Magmatic Province (CAMP) in Brazil are temporally linked to the end-Triassic extinction (ETE), one of the largest mass extinctions of the Phanerozoic. The sills were emplaced into the volatile-rich sedimentary rocks of the Amazonas and Solimoes basins in northern Brazil. Here we present a new geochemical study of 26 dolerite samples from 6 deep boreholes in the Brazilian basins, including whole-rock major and trace elements, whole-rock Sr–Nd isotopes and detailed biotite mineral chemistry. The bulk of the dolerites are characterized by phenocrysts of clinopyroxene and plagioclase in subophitic to intergranular textures, Fe–Ti oxides, and rare olivine and orthopyroxene. A different mineralogical assemblage (microphenocrysts of alkali-feldspar, quartz, biotite and apatite) is found in small independent domains, localized within the framework of coarser plagioclase and clinopyroxene laths. These fine-grained evolved domains crystallized in late-stage, evolved melt pockets in the interstitial spaces between earlier crystallized coarser grained crystals. The majority of the studied dolerites are generally evolved tholeiitic basalts and basaltic andesites with low TiO2 concentrations ( 2.0 wt.%), and are found in the eastern part of the Amazonas Basin. Whole-rock major and trace element and Sr–Nd isotope geochemistry of both low- and high-Ti sills is similar to that of previously published CAMP rocks from the two magma types. Low-Ti sills show enriched isotopic signatures (143Nd/144Nd201Ma 0.51215 to 0.51244; 87Sr/86Sr201Ma 0.70568 to 0.70756), coupled with crustal-like characteristics in the incompatible element patters (e.g. depletion in Nb and Ta). Unaltered high-Ti samples show more depleted isotopic signatures (143Nd/144Nd201Ma 0.51260 to 0.51262; 87Sr/86Sr201Ma 0.70363 to 0.70398). Low-Ti dolerites from both the Amazonas and Solimoes basins contain biotite with extremely high Cl concentrations (up to 4.7 wt.%). We show that there is a strong correlation between host-rock lithology and Cl concentrations in biotite from the dolerites, and interpret this to reflect large-scale crustal contamination of the low-Ti magmas by halite-rich evaporites. Our findings support the hypothesis that sill-evaporite interactions increased volatile release during the emplacement of CAMP. This strengthens the case for active involvement of this LIP in the end-Triassic crisis, and suggests that the sub-volcanic part of a LIP can be of major importance in driving climate change and mass extinctions.

Continental breakup between Greenland and NW Europe in the Paleogene was associated with transient massive magmatism and a global hot-house named the Paleocene-Eocene Thermal Maximum (PETM). The International Ocean Discovery Program (IODP) Expedition 396 will study the cause of this magmatism and its climate implication by drilling up to nine boreholes across the Vøring and Møre continental margins in August-September 2021. The expeditions will be conducted in conjunction with ICDP project PVOLC which plan to drill the Paleogene sequences in a more distal setting in Denmark in 2022. The NE Atlantic conjugate volcanic rifted margins are characterized by extensive break-up magmatism recorded by basalt flows, volcanogenic sediments, magmatic underplates, and intrusive complexes in sedimentary basins and the crust. Massive injection of magma into organic-rich sedimentary basins is a likely mechanism for triggering short-term global warming during the Paleocene-Eocene Thermal Maximum (PETM). A key objective of this expedition is to document the nature and explain the causes and consequences of excess magmatism during breakup as the large amount of magmatism cannot be easily be explained by passive decompressional melting of sub-lithospheric mantle with a normal potential temperature. New constraints on 1) melting conditions, 2) timing of magmatism, 3) spatial and temporal variations, 4) eruption environment, 5) sedimentary proxy data, and 6) temporal resolution of magmatism and climate change events are required to resolve current controversies. Systematic IODP drilling is a way to provide these constraints and will allow the development of a quantitatively testable framework for volcanic rifted margin formation and consequences for global climate change. New 3D seismic data collected by the industry and academia during the past few years have provided unique imaging of the basalt and sub-basalt sequences and allowed for optimal planning of the drill sites for scientific purposes. Additional holes are located along and outboard of the continent-ocean boundary to constrain the temporal evolution of the breakup magmatism. Two of the scientific drilling aims of this cruise are to core Paleogene sequences across the PETM and to drill one of the thousands of hydrothermal vent complexes to attain a proximal record of NAIP activity. This will give vital information on the proximal environmental disturbances during the NAIP emplacement.

The Paleocene-Eocene Thermal Maximum (PETM) is recognized as one of the potential analogues in the geological record for present-day global warming. The aim of the International Continental Scientific Drilling Program (ICDP) project PVOLC is to test the hypothesis that voluminous magmatism in sedimentary basins in the NE Atlantic triggered the PETM. Two ICDP boreholes are planned to core the boundary in the Limfjorden area in Denmark in 2022. PVOLC will be conducted in conjunction with IODP Exp 396 on the mid-Norwegian continental margin. The North Atlantic Igneous Province (NAIP) was is a large igneous province (5–10 million km3 magma) that coincided with both the opening of the NE Atlantic Ocean and the greenhouse conditions of the early Paleogene. The close temporal correlations suggest a possible causal relationship between the NAIP and both the climatic and tectonic changes around 56– 54 Ma. In particular, the main acme of NAIP activity occurred across the Paleocene–Eocene Thermal Maximum (PETM), an extreme hyperthermal event that represents the warmest conditions of the last 60 million years. The NAIP is among several proposed candidates for driving global warming through CO2/CH4 emissions, both by magmatic degassing and through contact metamorphism around shallow intrusions in organic rich sedimentary basins. What is needed to refine the role of the NAIP during the PETM are key sedimentary sequences that contain abundant volcanic and climatic proxies in the same section, thereby allowing a precise geochronology of events to be attained. The sediments exposed on the Fur island, Denmark, are a key sequence of PETM and post-PETM strata with little thermal overprint and hundreds of well-preserved volcanic ash layers from the NAIP. The effects of Quaternary glaciotectonism have disturbed this key stratigraphic interval at Fur, but seismic surveys indicate that undisturbed strata are found a few km to the south. The ICDP PVOLC project plan is to drill both the Paleocene-Eocene and the Cretaceous-Paleocene boundaries, hopefully recovering pristine cores suitable for high-resolution geochemical and climatic studies.

Tree trunks in lava flows and volcaniclastics of the Siberian Traps witness volcanic activity's violent and rapid onset. Carbonized and petrified trees preserve the peak metamorphic temperatures, which can be estimated using Raman spectroscopy. We have conducted a Raman study of the tree trunks and wooden fragments trapped in the Siberian Traps volcaniclastics and lavas on the Tunguska basin's northwestern region (Norilsk area). The first sample set was taken from volcaniclastic rocks of the Kureika River. The second sample set was collected from the lowermost lava flow of Ivakinskaya Formation that erupted directly on the end-Permian boggy surface (Tunguska Group of Carboniferous-Permian age) and from the coal-bearing inter lava seam at Red Rocks outcrop near Talnakh. The third sample set was taken from in the basal part of the Ivakinskaya Fm lowermost lava flow erupted in a shallow water basin with pillow basalt formation (Ore Brook near Norilsk). The fourth sample set was taken from an open coal pit with shallow dolerites intruded into the late Permian part of the Tunguska Group (near Kajerkan). We analyzed carbonized wood with a Renishaw InVia Qontor with 532 nm laser and processed all spectra with Henry et al. (2018) recommendations. The peak metamorphic temperature was calculated from Deldicque et al. (2016) equation 2. The tree trunks of the first sample set (Kureika River volcaniclastics) have a narrow median temperature range (430-468oC with one sample of 612oC). The second sample set from tree trunks in lavas and the coal-bearing inter lava seam (Red Rocks near Talnakh) ranges between 343-658oC and 742-764oC. The third sample set from pillow basalt at the basal part of Ivakinskaya Fm. (Ore Brook near Norilsk) also has a narrow temperature range (503-535oC with one sample of 650oC). The last sample set from the open coal pit (near Kajerkan) has a wide median temperature range (388-632oC).We explain these variations by different styles of the Siberian Traps eruption. At the Kureika River, the end-Permian forest was buried and carbonized by tephra. At the Talnakh area, lava flow erupted on the boggy surface, whereas in the Norilsk area, the lava flow erupted into the freshwater basin. Henry, D.G. et al. (2018). Int. J Coal Geol, 191: 135-151Deldicque, D. et al. (2016). Carbon, 102: 319-329

The Permian period ended with a mass extinction event about 252 million years ago. A likely trigger of the mass extinction was the eruption of large volumes of magma which had moved through the Tunguska Basin in Siberia. The renowned Festningen section in the outer part of Isfjorden, western Spitsbergen, offers a c. 7 km long nearly continuous stratigraphic section of Lower Carboniferous to Cenozoic strata, where the end-Permian extinction interval is well-exposed. Tectonic deformation associated with the Paleogene West Spitsbergen fold-and-thrust-belt tilted the strata to near-vertical, allowing easy access along the shoreline. The section is a regionally important stratigraphic reference profile and is a key locality for geologists visiting Svalbard. The main objective of our fieldwork in September 2020 was to collect closely spaced mudstone (0.25 to 1 m interval) and ash layer (6 layers of 0.5 to 1.5 cm thickness) samples across the Festningen Permian-Triassic boundary for chemostratigraphic and geochronological assessments. Carbon isotope data reveal a well-defined negative deltaC13 excursion in the lower part of the Vardebukta Fm. Zircons are present in most of the ash layer samples and these will be dated at the University of Oslo TIMS U-Pb Isotope Geology Laboratory. In this contribution, we will also present a new digital outcrop model of the P-Tr boundary section acquired using a UAV (Mavic 2 Pro, 20MP Hasselblad camera). During acquisition, the maximum drone speed was set to 1 meter/second (i.e., “tripod mode”), and photographs were taken automatically at set time intervals (e.g., 1 photo every 5 seconds ≈ meters). The digital outcrop model offers a pixel resolution of 7.27 mm/pixel. The Festningen model will be available online through the Svalbox.no geoscience data platform.

The Barents Sea shelf has been coverded by a numerous wide-angle seismic profiles, aiming to resolve the crustal structure of the shelf. However, the overall structural arcitecture of the crystaline crust is still not fully understood, due to limited and sparse distribution of deep-sampling seismic profiles. The petroleum related seismic exploration in Norwegian waters has been ongoing for decades. The recent increase of the seismic broadband stations onshore (including temporal deployments) provokes the idea to use these stations and the active seismic sources from the regional seismic reflection surveys, including academic and industry seismic projects, to reveal the crustal scale structure of the western Barents Sea.We have analyzed seismic records from 8 permanent seismic stations from Norway, Sweden and Finland, and 12 temporally deployed broadband seismic stations from the ScanArray seismic network, which recorded more than 100’000 marine airgun shots from academic and oil industry campaigns in the south-western quarter of the Barents Sea.The overall quality of the seismic records is exceptionally good. We clearly identify phases recorded from the offsets reaching 750 km. The identified phases include refracted crustal and mantle arrivals as well as Moho reflections, including both P and S waves. The overall quantity, quality, and the geometry of the seismic data makes it perfect for the application of the 3D joint refraction/reflection travel time seismic tomography to study the crustal structure of the Barents Sea.The preliminary results show very complex and laterally inhomogeneous crustal structure of the Barents Sea, which has been known before. However, with the help of 3D seismic tomography we are able to cover the gaps in between isolated deep-sampling seismic profiles and cross-correlate structures identified on them. In this work we would like to present our up-to-date results from the 3D seismic tomography.