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

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

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

The Lower Cretaceous succession in Svalbard contains numerous glendonites, pseudomorphs after the cold-water carbonate mineral ikaite, which have been used in conjunction with other evidence to argue for episodic global cooling punctuating the greenhouse climates of the Early Cretaceous. Recent fieldwork in central Spitsbergen has recovered giant bladed glendonites of up to half a metre long, the largest ever recorded in a Lower Cretaceous site, and comparable in size to outlier glendonites found in similar-aged strata of the Sverdrup Basin in Arctic Canada. Unlike the rosette to pineapple-like morphologies seen in some of the largest Canadian Arctic specimens, the new finds in Svalbard appear only as single or crossed blades. These large glendonites, found closely associated with numerous smaller, stellate examples in the same stratigraphic interval, indicate that very local variations in pore water chemistry governed whether numerous small ikaite crystals or few large crystals grew. Taken with evidence from modern ikaite and other large ancient glendonites, we argue that large glendonites such as these (>30 cm long) are pseudomorphs after ikaites that took, at the shortest, decades, but potentially millennia to even tens of millennia to attain their massive size. As growth of the parent ikaite took place in the sediments just below the seafloor of the shallow, epicontinental seas of the High Arctic (then situated at c. 63–66°N), this is consistent with the hypothesis that geologically short-term cooling episodes interrupted the background warmth of the Early Cretaceous greenhouse, although the duration, extent, and cause of such cooling is still debated.

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

The Lundy Island granite (Bristol Channel, UK) is a felsic expression of the southernmost igneous centre of the North Atlantic Igneous Province (NAIP) that emplaced millions of km³ of magma in the Paleogene. The distinctive S-type, peraluminous, two mica ± garnet ± tourmaline composition has led to the hypothesis that eruptions from the Lundy volcanic centre may be the source of thick felsic ash layers within the early Eocene Fur Formation (Denmark) that act as key marker horizons for the onset and duration of the Paleocene–Eocene Thermal Maximum (PETM). This study presents high-precision zircon U-Pb emplacement ages of 57.24 ± 0.11/0.12/0.13 Ma for the granite and 55.970 ± 0.021/0.030/0.070 Ma for a felsic 'lundyite' dyke. Trace and REE element patterns indicate close similarities between late-stage Lundy activity and ash layer '-33' in Denmark that was deposited during the PETM carbon isotope excursion, suggesting that this centre is likely to be the source of this key ash horizon and that magmatism at Lundy likely continued into the early Eocene.

The Late Paleozoic ice age (LPIA) is the longest-lived Phanerozoic icehouse climate and the only recorded greenhouse–icehouse–greenhouse cycle on a vegetated Earth. Sedimentary archives partially detail the glaciation events, but the reasons and timing of the LPIA's onset (∼330 Ma) and end (∼260 Ma) remain debated. In many models, the shift to icehouse conditions is linked to enhanced CO2 uptake through silicate weathering, but the causes of this increased carbon sink are unclear. Most carbon cycle models are limited by their non-dimensional nature, and spatially resolved models rely heavily on variables such as topography and bathymetry, which are difficult to constrain over time. This study investigates the influence of weatherability reconstructions in non-dimensional versus spatially resolved models in the context of the LPIA's onset and ending. We review constraints on simulated silicate weathering fluxes and test forcings affecting its rate. Our paleogeographic forcing review uses newly developed land-maps and reconstructed climatic belts to constrain weathering based on fossil paleo-indicators. Our findings suggest that increased land availability in the high weatherability zones (HWZ) led to enhanced weathering processes, likely contributing to the glaciation onset. However, when a high solid Earth degassing factor is included, the likelihood of an extensive glaciation diminishes, indicating the need for an intensified CO2 sink driven by higher erosion rates and associated chemical weathering tied to topographic elevation to instigate widespread glaciation. A reduction in available land for weathering in the HWZ appears to have a determining role in the LPIA's termination.

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

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.

Geologically, the Arctic is one of the least-explored regions of Earth. Obtaining data in the high Arctic is logistically, economically, and environmentally expensive, but the township of Longyearbyen (population of 2617 as of 2024) at 78° N represents a relatively easily accessible gateway to Arctic geology and is home to The University Centre in Svalbard (UNIS). These unique factors provide a foundation from which to teach and explore Arctic geology via the classroom, the laboratory, and the field. UNIS was founded in 1993 as the Norwegian “field university”, offering field-based courses in Arctic geology, geophysics, biology, and technology to students from Norway and abroad.

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