Recovering geological samples from the deep basins and ridges of the central Arctic Ocean presents significant challenges because of remote access and thick ice cover. During the 2016 Canada-Sweden Polar Expedition to the Arctic Ocean, volcaniclastic breccia was dredged from the Alpha Ridge, part of an underwater mountain chain extending from the Canadian polar margin to the Siberian shelf. Argon geochronology of plagioclase crystals within glassy lava fragments dates the sample to 90.4 ± 0.26 Ma. The geochemical composition of basalt clasts in the volcaniclastic breccia closely resembles that of igneous rocks from the High Arctic Large Igneous Province suggesting that the Alpha Ridge was an active volcanic feature within the circum-Arctic in the Late Cretaceous. Our results support lava–water interactions in a littoral environment, driven by the growth and emergence of a central igneous platform and accompanied by eruptive activity at constructional volcanic edifices along its margins. Fresh basaltic glass preserved in a sample of volcanic breccia record a single eruptive event at the Alpha Ridge around 90 Ma, suggesting that parts of the ridge were emergent during the final stages of magmatism in the High Arctic Large Igneous Province, according to geochemical and geochronological analysis of the sample.

The Northeast Atlantic was one of the last regions of the Pangea supercontinent to undergo complete break-up, experiencing over 200 million years of episodic continental stretching before final separation. This prolonged tectonic evolution has been studied using recent geological and geophysical data obtained from the midNorwegian and East Greenland margins, which provide constraints on the timing, location, amount, and direction of extension. To analyse these parameters, we adopt a basin-to-plate scale approach and develop a deformable plate reconstruction. We implement four discrete phases of rifting: Phase I (264-247 Ma), Phase II (166-140 Ma), Phase III (125-110 Ma), Phase IV (80-56 Ma), with a progressive shift in extension direction from east-west to southeast-northwest. A key component of our methodology is the restoration of basin hinges for each rift episode. These hinges mark the outermost rigid boundaries of the deforming region and provide essential structural constraints. Over time, the width of the rifting domain narrows from approximately 300 km to 220 km, depending on margin location. Our model predicts cumulative stretching ranging from 240 km in the north to 310 km in the south of the domain. Extension rates and amounts vary by phase; for a mid-margin location, Phase I accounts for approximately 90 km of extension at 0.5 cm/yr, Phase II for 30 km at 0.13 cm/yr, Phase III for 90 km at 0.58 cm/yr, and Phase IV for 80 km at 0.32 cm/yr. By comparing forwards- and backwards-in-time crustal thickness reconstructions, our results suggest an initial crustal thickness exceeding 35 km before the onset of Permian rifting, and that lateral variations of non-linear stretching were likely. Our framework indicates that both rigid and deforming reconstructions should be developed in tandem with regional basin-scale constraints. Our model will form the basis for additional regional temporal and structural investigations including the Barents Sea, North Sea, and Northwest North Atlantic.

Fluid dynamics simulations are a powerful tool for understanding processes in the Earth's deep interior. Mantle circulation models (MCMs), for example, provide important insight into the present-day structure of the mantle and its thermodynamic state when coupled with mineralogical models, which is essential information for other fields in the geosciences. The evolution of the heat flux through the core-mantle boundary, for instance, is a prerequisite for geodynamo simulations that aim to model the reversal frequency pattern of the Earth's magnetic field on geologic time scales. However, geodynamical modelling requires extensive knowledge of deep Earth properties and plate motions over time. Uncertainties in these model inputs propagate into the MCMs, which subsequently have to be evaluated with independent data, such as the seismological or geological record. Although state-of-the-art MCMs typically explain statistical properties of seismological data, they do not consistently reproduce the location of features in the mantle. In this contribution, we explore the effect of varying the absolute position of mantle structure on seismic data by applying first-order modifications to an initial MCM. Normal mode data are particularly well suited for assessing the resulting changes in the location of mantle structure, as they capture its long-wavelength component throughout the entire mantle. In addition, the global sensitivity of normal modes reduces the drawbacks of uneven data coverage. Specifically, we use two different seismic forward modelling approaches, an iterative direct solution method for computing full-coupling spectra and a splitting function calculation that is based on the self-coupling approximation. Our goal is to quantify the effects of a limited number of large-magnitude earthquakes, the adequacy of the self-coupling approximation, and the resolvability of relevant model differences through a comprehensive data analysis. Our synthetic forward modelling framework is moreover well suited for testing the depth sensitivity associated with specific frequency intervals in the spectrum that generally is inferred from seismic 1-D profiles within the splitting function approximation.

The Svalbard archipelago, located in the Norwegian High Arctic, preserves more than 650 million years of near-continuous sedimentary rock records spanning from the Neoproterozoic to the Cenozoic. The polar paleogeographic location of Svalbard in the late Mesozoic and the Cenozoic makes sites in Svalbard unique amongst well-studied temporally equivalent successions from lower paleolatitudes, allowing investigation of the polar amplification climatic effect over geological time. The sedimentary record of Svalbard has been largely controlled by northward drift of constituent geological provinces throughout much of the Phanerozoic and evolving tectono-stratigraphic environments including the influence of several Large Igneous Provinces (LIPs) and global climate fluctuations. The SVALCLIME initiative aims to systematically drill and core the sedimentary successions in Svalbard. Two sub-projects currently being evaluated by the ICDP materialized from an international workshop held in Longyearbyen in October 2022. The first is a full ICDP proposal focused on hyperthermals from the Permian to Paleogene (SVALCLIME P2P) and an ICDP-IODP Land to Sea preproposal on hothouse to coldhouse transitions in the late Paleozoic and across the Eocene–Oligocene transition (SVALCLIME Hot2Cold).The SVALCLIME P2P project aims to investigate the high-resolution Arctic paleoclimate record from 255 to 45 Ma onshore Svalbard that encompasses several Mesozoic and Cenozoic hyperthermal events and the near-field impacts of three LIPs (the Siberian Traps, the High Arctic LIP and the North Atlantic Igneous Province). Our focus will also be on the deep biosphere to uncover the relationship between mineral substrates and taxonomic and metabolic diversity of intraterrestrial microbiomes. We propose to core seven boreholes at three locations (Nordenskiöldfjellet, Botneheia and Kropotkinfjellet), with a cumulative total cored length of ~3.4 km. The SVALCLIME Hot2Cold project aims to address global transitions from hothouse to icehouse conditions during the late Paleozoic and the Eocene to Oligocene. In the preproposal we identify suitable drill sites both onshore and offshore to characterize these periods. The Forlandsundet Graben in western Spitsbergen offers an opportunity to decipher the evolution of the Fram Strait and its impact on global oceanographic circulation during the Eocene–Oligocene transition. The Upper Carboniferous to Early Permian syn and post-rift deposits of the Billefjorden Trough will be targeted to investigate >130 cyclothems originating from glacioeustatic sea level fluctuations.In this contribution, we outline the background and motivation of the SVALCLIME initiative and present the scientific objectives and the proposed drill sites.

Between about 130 and 75 Ma, the Arctic was impacted by widespread and long-lived volcanism known as the High Arctic Large Igneous Province (HALIP). HALIP is a very unusual large igneous province because it exhibits prolonged melting over more than 50 Myr with pulses of activity, an observation that is difficult to reconcile with the classic view of large igneous provinces and associated melting in plume heads. Hence, the suggested plume-related origin and classification of HALIP as a large igneous province has been questioned, and alternative mechanisms have been invoked to explain at least part of the volcanism. However, the Arctic also exhibits a very complex and time-dependent tectonic history that includes cratons, continental margins and rifting, all of which are expected to interact with the rising plume and affect its melting behaviour. Here, we use 2-D numerical models that include melting and melt migration to investigate a rising plume interacting with a lithosphere of variable thickness, i.e. an extended-basin-to-craton setting. Models reveal significant spatial and temporal variations in melt volumes and pulses of melt production, including protracted melting for at least about 30-40 Myr, but only if feedback between melt and mantle convection is accounted for. In particular, we find that melt migration transports heat upwards and enhances local lithospheric thinning, resulting in a more heterogeneous distribution of melting zones within the plume head underneath the Sverdrup Basin. Once the thicker continental and cratonic lithosphere move over the plume, plume material is deflected from underneath the Greenland craton and can then re-activate melting zones below the previously plume-influenced Sverdrup Basin, even though the plume is already ∼500 km away. Hence, melting zones may not represent the location of the deeper plume stem at a given time. Plume flux pulses associated with mantle processes, rifting of tectonic plates or magmatic processes within the crust may alter the timing and volume of secondary pulses and their surface expression, but are not required to generate pulses in magmatic activity. Hence, we propose that the prolonged period of rejuvenated magmatism of HALIP is consistent with plume impingement on a cratonic edge and subsequent plume-lithosphere interaction. Based on melt fractions, our models suggest that HALIP magmatism should exhibit plume-related trace element signatures through time, but potentially shifting from mostly tholeiitic magmas in the first pulse towards more alkalic compositions for secondary pulses, with regional variations in timing of magma types.

AbstractGravity data provide constraints on lateral subsurface density variations and thus provide crucial insights into the geological evolution of the region. Previously, gravity data from the Norwegian Arctic archipelago of Svalbard comprised an onshore regional gravity database with coarse station spacing of 2–20 km, offshore gravity profiles acquired in some fjords, airborne gravity, and satellite altimetry. The sparse regional point‐based onshore coverage hampered the direct integration of gravity data with seismic profiles acquired onshore Svalbard in the late 1980s and early 1990s. In April 2022, we acquired gravity data at 260 new stations along seven profiles from western to eastern Spitsbergen, with a cumulative length of 329 km. The profiles were acquired directly along selected seismic profiles and provide much closer station spacing (0.5–2 km) compared to the regional inland grid (2–20 km) acquired in the late 1980s (total number of onshore stations: 1,037). Having processed the data, we compared the first‐order density trends of our new data with the legacy regional grid. The new gravity data are consistent with the regional data, imaging a gravity low in the western part of the area underlying a foreland basin and a gravity high in the northwestern part of the area likely associated with a basement high or denser basement. We compare the new and vintage gravity using maps and profiles, linked to the known major tectonic features such as major basinal axes and fault zones, as well as other geophysical data sets including seismics and magnetics.

Large Igneous Provinces are defined as magmatic provinces with large magma volumes (> 100,000 km3) emplaced and/or erupted in an intraplate tectonic setting over a vast area within a few Myr, thus having the potential for significant impact on the global climate. The High Arctic Large Igneous Province (HALIP) was emplaced during the Cretaceous. The available ages, ranging between ~140 and 80 Ma, suggests that the magmatism was apparently long-lived and multi-phase. Extrusive and intrusive remnants of the HALIP can be found across the circum-Arctic, specifically in Arctic Canada, Russia, Svalbard, Northern Greenland, and the Arctic Ocean. On Svalbard, the HALIP magmatism is regionally called the Diabasodden Suite. Here, the dolerites have mainly been emplaced as sills at shallow depths and occur all over the archipelago. Despite the relative accessibility of outcrops, the HALIP on Svalbard has been mostly unexplored. As such, available U-Pb geochronology of the Diabasodden Suite is limited, but indicates a shorter time span of 125 – 122 Ma. Yearly field campaigns since 2020 have resulted in over 150 collected samples from Spitsbergen and Nordaustlandet. This has been accomplished through a collaborative effort, and by strategically targeting outcrops to build a good representative dataset of the Diabasodden Suite. Additionally, a large number of samples have also been taken for a detailed case-study in central Spitsbergen. The dolerite samples are used for whole-rock major and trace element geochemical analysis, U-Pb baddeleyite geochronology and petrological studies. Furthermore, during all field campaigns, high-resolution drone images have also been acquired. These data form the basis for digital outcrop models (DOMs), which are used for thickness measurements of the sills and to put the geochemical data into a 3D perspective. The resulting DOMs are made openly available through the geoscientific database of Svalbard, SvalBox. Here we present a review of the available geochronology of the HALIP in the circum-Arctic, as well as new data from Svalbard. Specifically, new U-Pb baddeleyite ages of one mafic sill in northern Isfjorden, and an extensive dataset of whole-rock geochemical data from the HALIP on Svalbard to better understand the magmatic history of the HALIP as a whole.

Constraining the evolution of the opening of the northernmost region of the Northeast Atlantic Ocean is of particular importance for understanding the diversity of ocean basin opening dynamics, including the development of oblique margins and shear zones. Accurately determining the timing and kinematics of the motion along the Senja Shear Zone and opening of the Fram Strait is of particular importance for climate research as this region forms the only deep-water gateway between the Northeast Atlantic Ocean and Arctic Ocean. This study combines new and legacy data and presents an analysis of the tectonic evolution of the northern Norwegian passive margin over the past 200 Ma, including integrating structural field observations and plate tectonics models. Fieldwork took place on the islands of Senja and Kvaløya in Troms County of northern Norway. The field observations reveal four dominant brittle fault groups corresponding to four normal-oblique extension directions: E-W, NNW-SSE, NW-SE, NE-SW. In the Senja Shear Zone, the strike-slip faults are predominantly oriented NNW-SSE to NW-SE. Analysis of existing plate motion models for the region for 200 Ma to present day includes three prominent extension phases in chronological order: E-W, NNW-SSE, and NW-SE. This study suggests that during the E-W oriented crustal thinning phase, normal faulting and minor strike-slip faulting dominated and gave way to basement-seated strike-slip faults during the NNW-SSE oriented extension phase. The presence of mid-upper crust faulting is argued by fault mineral striation assemblages and hydrothermal alteration. In the NW-SE oriented extensional phase, both normal faults and strike-slip faults were active. Comparisons to existing rigid plate tectonic models for the region suggest a revised deformable plate framework is required, and offers insights into the original thickness of the North-American and European plates and the role of mid-crustal tectonics in the breakup. The role of inheritance, including earlier shear zones and extensional phases will also be discussed. In addition, the present research encourages scientists to digitize analogue maps and data, preventing loss of knowledge during the analogue to digital transition.

Launched in early 2022, the s-Ink project makes high-quality (geo)scientific figures freely available via an always-on online platform, https://s-ink.org. The website hosts figures that can be searched and downloaded by everyone, including students, researchers, teachers, the media, and the public. Hosted content is intentionally broad in nature, and can include data visualisations, animations, artistic impressions, icons, templates, and more.The open graphics collection, that is also designed for you to share your own graphics, is built around the fundamental principles of science: accuracy, accessibility, and acknowledgment. First, the graphics hosted on s-ink.org are subject to transparent and permanent community-review, versioned and therefore updatable to the latest understanding – an academic novelty. Second, s-Ink graphics are, without exception, universally readable, also to colour-blind viewers – an academic rarity. Third, all content has metadata and is licenced (e.g., via Creative Commons), so those who create the images and the sources they are based on will receive credit.The s-Ink.org initiative is currently coordinated by three scientists, working on a volunteer-based approach with non-permanent contracts (one a free-lancer, two with the backing of employers). We are finding financial sponsors to cover the minimal costs involved and actively bridge other valuable community initiatives by hosting their graphical and providing our educational resources.Both the collection and the contributing creators are ever-growing, and the rising views and downloads are signalling the demand. The open collection of geoscience graphics that we envisage (see Crameri et al., 2022) is of direct use well beyond to geoscience community. Indeed, somewhat of a holy grail to science communication.Crameri, F., G.E. Shephard, and E.O. Straume (2022, Pre-print), The open collection of geoscience graphics, EarthArXiv, https://doi.org/10.31223/X51P78

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

The Northeast Atlantic is a key region where advances in plate tectonics have been developed, tested, and refined. Final breakup and the onset of seafloor spreading started around magnetic Chron C24n (~55 Ma; earliest Eocene). However, prior to breakup, the Northeast Atlantic’s margins underwent at least four discrete phases of lithospheric-scale rifting and basin formation, extending back to mid-Permian times (ca. 264 Ma) following the Caledonian orogeny. The total amounts of extension are in the order of several hundred kilometers and therefore relevant to implement in regional and global plate tectonic reconstructions. Recently, deformable plate models using the GPlates software have emerged as a tool to capture such non-rigid domains. However, deformable models to-date have been largely constructed in an overall rigid plate framework, applying pre-existing Euler rotations from the surrounding plates to the intervening rift. Here we detail why, and how, a basin-to-plate scale approach should be considered in future regional and global refinements of deforming reconstructions, using the multi-phase Northeast Atlantic rifting as a focus site. We place basin-scale observations based on extensive seismic, stratigraphic and geophysical interpretations for the Norwegian margin and its Greenland conjugate (Abdelmalak et al. 2023) into new digital plate tectonic model (Shephard et al., in review). Central to our methodology is identification and restoration of rift basin hinges, and accounting for their along-margin variability. In this presentation we will detail the timing, location, amount and direction of extension across four discrete rift phases and their associated time-dependent rotations. A conjugate profile from the Foster and Northern Vøring margins (totalling 282 km of extension at average rates ranging between 0.13-0.58 cm/yr during rifting) yields the best fit accounting for along-margin heterogeneity whilst retaining the overall rigid framework requirements. We compare our results to previous regional models, including Barnett-Moore et al. (2018) and Müller et al (2019), and showcase some of the GPlates scalar field functionality including crustal stretching and tectonic subsidence. Finally, we have also developed an external routine for a backward-restored crustal thickness workflow which successively restores present-day thickness in conjunction with our deformable model.

Seismic imaging of the Earth’s interior reveals plumes originating from relatively hot regions of the lowermost mantle, surrounded by cooler material thought to be remnants of ancient subducted oceans. Currently, there is no clear consensus on the internal composition of the hot regions, with end-member conditions being that they are thermo-chemical in nature or purely thermal plume clusters. Previous modelling studies have shown a range of scenarios where deep chemical heterogenities or purely thermal anomalies are essential in developing appropriate present-day mantle dynamics. Here, we add to this discus- sion by quantifying the location of rising mantle plumes using numerical 3-D global mantle convection models constrained by 410 million years of palaeo-ocean evolution (encompassing the formation and breakup of supercontinent Pangea). Our study compares numerical simulations with purely thermal convection to those where a deep thermo-chemical anomaly is laterally mobile. The results show that models both with and without large-scale chemical heterogeneities can generate appropriate present-day plume dynamics, which illustrate the power of sinking ocean plates to stir mantle ow and control the thermal evolution of the mantle. Our models add to the discussion on bottom-up and top-down mantle dynamics, indicating the difficulty in unravelling the processes using numerical models alone.

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.

A number of widely used colour palettes applied to display critical scientific results not only distort data but are also inaccessible to a proportion of the population. An issue with the rainbow palette (and variants such as “jet”) is that the gradients between the colours are not even. The impact of an uneven colour gradient is that certain colours are highlighted over others, distorting the underlying data. Furthermore, an uneven colour palette like rainbow may be inaccessible for people with colour vision deficiencies or colour blindness. When communicating scientific results, data should always be presented without distortion and be universally accessible. This is particularly important when communicating public-facing and time-critical information such as hazards. Here, we show the impact of changing the visualisation profile of seismic hazard maps on the perception of risk, as well as qualifying the public accessibility of this information. Using Canadian seismic hazard as an example, our results reveal that an uneven colour map applied to seismic hazard data can exaggerate lower hazard values and reduce the perception of extremely high hazard values. Applying an even colour gradient to our sample data not only allows this essential public resource to be universally accessible but was found to lead to the greatest visual change in regions with the most populated cities. The choice of colour map and subsequent data interpretations also holds relevance for considerations such as insurance. We highlight potential next steps to promote inclusiveness in data visualisation and welcome discussion on science communication best practices.

In a scientific context, a suitable color choice is more than simple decoration. Color handling, as part of scientific visualization, is a scientific methodology that is one of the most widely used, given the importance of figures and images in conveying results. Yet, an expert-level understanding and application of proper scientific coloring is rare. Here, a concise overview of important color tools is provided and complemented by ready-to-apply resources for using color in science research, publishing, communication, tool development, editing, and teaching. This overview offers a guide to spot problems, master the methodology, and support accessible and accurate use of color for science figures in both short and long terms. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC.

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

Large igneous provinces (LIPs) have been linked to both surface and deep mantle processes. During the formation, tenure and break-up of the supercontinent Pangaea, there is an increase in emplacement events for both continental and oceanic LIPs. There is currently no clear consensus on the origin of LIPs, but a hypothesis relates their formation to crustal emplacement of hot plume material originating in the deep mantle. The interaction of subducted slabs with the lowermost mantle thermal boundary and subsequent return flow is a key control on such plume generation. This mechanism has been explored for LIPs below the interior of a supercontinent (i.e. continental LIPs). However, a number of LIPs formed exterior to Pangaea (e.g. Ontong Java Plateau), with no consensus on their formation mechanism. Here, we consider the dynamics of supercontinent processes as predicted by numerical models of mantle convection and analyse whether circum-supercontinent subduction could generate both interior (continental) and exterior (oceanic) deep mantle plumes. Our numerical models show that subduction related to the supercontinent cycle can reproduce the location and timing of the Ontong Java Plateau, Caribbean LIP and potentially the Shatsky Rise by linking the origin of these LIPs to the return flow that generated deep mantle exterior plumes.

The widespread High Arctic Large Igneous Province (HALIP) exhibits prolonged melting over more than 50 Myr, an observation that is difficult to reconcile with the classic view of large igneous provinces and associated melting in plume heads. Hence, the suggested plume-related origin and classification of HALIP as a large igneous province have been questioned. Here, we use numerical models that include melting and melt migration to investigate a rising plume interacting with variable lithosphere thickness, i.e. an extended-basin-to-craton setting. Models reveal significant spatial and temporal variations in melt volumes and pulses of melt production, including protracted melting for at least about 30-40 Myr, but only if migrating melt transports heat upwards and enhances local lithospheric thinning. Plume material deflected from underneath the Greenland craton can then re-activate melting zones below the previously plume-influenced Sverdrup Basin, even though the plume is already ~500 km away. Hence, melting zones may not represent the location of the deeper plume stem at a given time. Plume flux pulses associated with mantle processes or magma processes within the crust may alter the timing and volume of secondary pulses and their surface expression. Our models suggest that HALIP magmatism is expected to exhibit plume-related trace element signatures throughout time, but potentially shift from mostly tholeiitic magmas in the first pulse towards more alkalic compositions for secondary pulses, with regional variations in timing of magma types. We propose that the prolonged period of rejuvenated magmatism of HALIP is consistent with plume impingement on a cratonic edge.

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