Carmen Gaina

• Senger, Kim; Ammerlaan, Fenna; Betlem, Peter; Gaina, Carmen; Galland, Olivier & Grundvåg, Sten-Andreas [Vis alle 21 forfattere av denne artikkelen] (2026). A Field Guide to the High Arctic Large Igneous Province in and Around Isfjorden, Svalbard. Tektonika. 3(2), s. 176–216. doi: https:/tektonika.online/index.php/home/article/view/124/197. Fulltekst i vitenarkiv Vis sammendrag

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

• Heincke, Björn H.; Szwillus, Wolfgang; Freienstein, Judith; Ebbing, Jörg; Gaina, Carmen & Ruppel, Antonia [Vis alle 8 forfattere av denne artikkelen] (2026). A new magnetic anomaly map for Greenland based on a combination of equivalent source modeling and spherical harmonic expansion. Earth System Science Data. ISSN 1866-3508. 18(3), s. 1967–1967. doi: 10.5194/essd-18-1943-2026. Fulltekst i vitenarkiv Vis sammendrag

  The Greenland Magnetic Map (GREENMAG) is a new compilation of magnetic anomaly data that covers the inland ice, ice-free coastal areas, and adjacent shelf regions of Greenland (https://doi.org/10.22008/FK2/LQN5YJ, Heincke and Szwillus, 2025). GREENMAG is based on all accessible modern regional aeromagnetic surveys from Greenland and vintage datasets without GPS positioning in areas where modern data are lacking. The magnetic anomaly map is generated by a combination of equivalent source (ES) modeling and spherical harmonic expansion. Hereby, the data points are used at their actual measurement location as input data for the inversion of the ES modeling. The equivalent sources are represented by magnetic dipoles that are arranged in three uniform grids with different source spacing and depths (coarsest spacing: 10 × 10 km; medium spacing: 2 × 2 km; finest spacing: 0.7 × 0.7 km). Regularization in the inversion for the different equivalent source grids are chosen such that the resulting resolution is adapted to the largely varying magnetic data coverage in Greenland. Since long wavelength components in aeromagnetic data are considered unreliable, they are replaced by the LCS-1 satellite model based on magnetic gradient measurements of the Swarm and CHAMP missions. For merging, the responses from the individual equivalent dipole sources are transferred to spherical harmonics and replaced for degree n = 13–133 by the Gaussian coefficients of the LCS-1 model. The final magnetic anomaly map is calculated from the combined model at a constant height of 2000 m a.s.l. (WGS84) and with a grid spacing of 400 × 400 m. The comparison between the GREENMAG and the earlier compilation from the Circum-Arctic Mapping Project (CAMP-M) highlights the enhanced level of detail now available across many regions of Greenland.

• Escartín, Javier; Sautter, Benjamin; Gaina, Carmen; Granot, Roi; Petersen, Sven & Pubellier, Manuel (2026). Global geometry of mid-ocean and back-arc ridge systems: Ridge segments, transform faults, and non-transform offsets. Earth-Science Reviews. ISSN 0012-8252. 281, s. 105633–105633. doi: 10.1016/j.earscirev.2026.105633. Fulltekst i vitenarkiv Vis sammendrag

  The total length of the global mid-ocean ridge system length is currently estimated at 50000 to 100000 km. To define in detail the complex structure of divergent plate boundaries, and to accurately evaluate its length and the geometry of ridge offsets, we present the MAPRIDGES database. It provides the first comprehensive global compilation of mid-ocean ridge geometry interpreted from multibeam bathymetry, encompassing in detail individual ridge segments, transform faults, and non-transform offsets (NTOs). The database includes 262 transform faults and 10 transform zones, totalling ∼28.000 km. We quantify for the first time both overlapping and underlapping NTOs at divergent plate boundaries and find a cumulative lateral offset of ∼9.000 km, representing one-third of the cumulative length of transform offsets. The database incorporates 1471 ridge segments reaching a total length of ∼71200 km, while the global ridge length corrected for NTOs overlaps and underlaps amounts to ∼67900 km. Mid-ocean ridge spreading rate exerts a first-order control on the geometry and nature of mid-ocean ridge segmentation. We document that at rates below a spreading rate threshold of ∼80-100 mm/yr, the proportion of overlapping NTOs increases with spreading rate, while the cumulative lateral offset decreases. At rates above this spreading rate threshold there is no apparent dependence of NTOs geometry on spreading rate. We also document that the lateral offset of NTOs and transforms show a significant overlap, with numerous transforms displaying offset lengths below 40 km, and NTOs exceeding 50 km. NTOs affect about 10% of the oceanic crust along-axis, reshaping the lithosphere with tectonic deformation, volcanism, hydrothermal activity and alteration. Consequently, these non-transform discontinuities, together with transform faults, should be systematically included in global assessments of lithospheric accretion, alteration, and associated fluxes of fluids and elements at mid-ocean ridges. We suggest that ridge segmentation and the nature of discontinuities are influenced by multiple factors beyond spreading rate, including mantle temperature, melt supply, and ridge obliquity, in addition to local intra- and inter-segment variability. Analyses of the patterns reported here might help understanding the nature and evolution of magmatic vs. tectonic-dominated ridge segments and their terminations.

• Shephard, Grace; Abdelmalak, Mohamed Mansour; Faleide, Jan Inge; Clennett, Edward; Zahirovic, Sabin & Gac, Sebastien [Vis alle 9 forfattere av denne artikkelen] (2026). Multi-phase intra-plate rifting and deformable plate modelling of the Northeast Atlantic back to the Permian. Gondwana Research. ISSN 1342-937X. 149, s. 465–490. doi: 10.1016/j.gr.2025.09.002. Fulltekst i vitenarkiv
• Knies, Jochen Manfred; Killops, Stephen; Brekke, Trond; Grøsfjeld, Kari; Sliwinska, Kasia K. & Planke, Sverre [Vis alle 13 forfattere av denne artikkelen] (2025). A prolific Tertiary source rock of terrestrial origin in the eastern Nordic Seas. Marine and Petroleum Geology. ISSN 0264-8172. 183. doi: 10.1016/j.marpetgeo.2025.107637. Fulltekst i vitenarkiv Vis sammendrag

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

• Ershova, Victoria; Stockli, Daniel; Gaina, Carmen; Khudoley, Andrey & Shimanskiy, Sergey (2025). When Big Rivers Started to Drain to the Arctic Basin: A View from the Kara Sea. Geosciences. 15(9). doi: 10.3390/geosciences15090342. Fulltekst i vitenarkiv Vis sammendrag

  This study provides new constraints on the paleogeographic evolution of the Arctic during the Mesozoic. U–Pb geochronology of detrital zircon and rutile grains, together with (U–Th)/He zircon thermochronological data from the uppermost Middle Jurassic to Cretaceous strata of the Sverdrup well in the Kara Sea, reveals a major shift in sediment provenance. Two distinct age populations of detrital zircon define this transition: Group 1 (Middle Jurassic–Hauterivian) shows dominant Neoproterozoic–Cambrian (ca. 700–500 Ma) and Paleozoic (ca. 350–290 Ma) peaks, whereas Group 2 (Aptian–Albian) is characterized by prominent Paleoproterozoic (ca. 1980–1720 Ma), Paleozoic (ca. 350–255 Ma), and Early Mesozoic (ca. 240–115 Ma) ages. Corresponding variations in (U–Th)/He zircon ages—from a Triassic peak (~225 Ma) in Group 1 to a dominant Early Cretaceous peak (~140 Ma) in Group 2—support a switch from a proximal to more distal sediment source. We propose that the emergence of large continent-scale river systems transported clastic material from the southern margin of the Siberian Craton to the Arctic Ocean starting in the late Early Cretaceous. The development of a significant freshwater supply potentially initiated a thick low-salinity layer within the surface waters of the central Arctic Ocean, possibly leading to the onset of a strong salinity stratification of near-surface water masses as in the modern Arctic Ocean.

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

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

• Anzulovic, Ana; Davis, Anne Hope; Gaina, Carmen & Caracas, Razvan (2025). Buoyancy of volatile-rich kimberlite melts, magma ascent, and xenolith transport. Geology. ISSN 0091-7613. 53(11), s. 919–923. doi: 10.1130/g53387.1. Fulltekst i vitenarkiv Vis sammendrag

  Kimberlite melts are primary carriers of mantle-derived carbon and hydrogen, playing an important role in Earth’s deep carbon cycle and diamond transport. Their low densities, viscosities, and vapor exsolution enable fast ascent rates. Ascending from the upper mantle, kimberlite melts incorporate xenoliths and xenocrysts and exsolve volatiles. These processes alter their initial composition, increasing the discrepancy between the proto-kimberlite magma and the magma that reaches the surface. To explain kimberlite volcanism, we examine atomic diffusivities and densities of kimberlite melts with varying volatile contents. We show that water makes the melts more diffusive, which should also lower their viscosity. All our kimberlite melts are positively buoyant below the lower continental crust (the MOHO discontinuity). They require ∼8.2 wt% CO2 to cross and rise through the MOHO. Above the MOHO, the most volatile-rich kimberlite melts can carry up to ∼44% xenolithic fragments of depleted peridotite type.

• Gaina, Carmen; Jakobsson, Martin; Straume, Eivind Olavson; Timmermans, Mary-Louise; Boggild, Kai & Bünz, Stefan [Vis alle 8 forfattere av denne artikkelen] (2025). Arctic Ocean bathymetry and its connections to tectonics, oceanography and climate. Nature Reviews Earth & Environment. 6, s. 211–227. doi: 10.1038/s43017-025-00647-0. Fulltekst i vitenarkiv Vis sammendrag

  For at least the past 50 million years, the Arctic region has had a major role in regulating global climate regimes and their variations through time. In this Review, we discuss the role of the Arctic oceanic basin and its complex bathymetry in controlling ocean circulation and marine cryosphere development. The spatial distribution and depth of various seafloor features, such as ocean gateways, submarine plateaus and continental shelves, influence the pathways of ocean currents, both today and in the past. The Arctic Ocean was an enclosed basin until the Early Eocene (56–48 million years ago), when the Eurasian Basin started to form and a shallow sea connected the Arctic to the Tethys Ocean. The connections with the North Atlantic and the global ocean through shallow and deep gateways prompted the transition from a global greenhouse to icehouse climate. However, the Arctic Ocean remains underexplored, as less than one-quarter of its seafloor is mapped in detail. Future integrated geoscience research, modern bathymetric mapping technology and active international programmes are needed to close these data gaps

• Salajegheh, Farshad; Afonso, Juan Carlos; Minakov, Alexander; Ajourlou, Parviz; Gaina, Carmen & Ortega-Gelabert, Olga (2025). The Lithosphere-Asthenosphere System Beneath the North Atlantic and Surroundings: Results From Multi-Observable Probabilistic Inversions. Geochemistry Geophysics Geosystems. 26(2). doi: 10.1029/2024GC011724. Fulltekst i vitenarkiv Vis sammendrag

  The North Atlantic region is a complex geodynamic setting that comprises multiple continental blocks, sedimentary basins, mid-ocean ridge systems and prominent hotspots. Recent geophysical surveys of the near-surface have enhanced our understanding of crustal elements and the shallow lithosphere. However, our knowledge of the deep lithospheric structure and the physical state and dynamics of the upper mantle is still limited. Here, we exploit the combined sensitivity of surface-wave data, geoid anomalies, absolute topography and surface heat flow to obtain full thermochemical models of the region from the surface down to 350 km. We jointly invert these data sets using a simulation-based, multi-observable probabilistic framework. We validate our results with independent thermobarometric and chemical information from mantle xenoliths and test the effects of using different seismic models on the inversion results. Our model reveals an intricate sublithospheric flow system, driven by the interaction of deep upwellings with the highly irregular lithospheric structure. We corroborate that the main thermal anomaly in the sublithospheric mantle shows a tilted geometry, moving toward Greenland with depth. We reveal that this large-scale anomaly transition into a more complex pattern once it reaches depths of 150 km beneath the North Atlantic. Small-scale downwellings originate from the margins of continental domains, resulting in a complex circulation pattern that limits the radial spread of the deep upwellings and preferentially focuses them within regions of thin lithosphere along a N–S direction. Distinct compositional anomalies in the Greenland lithosphere delineate the North Atlantic Craton, the Nagssugtoqidian mobile belt, and the covered remnants of the Disko Craton. In continental Europe, the East European Craton shows clear indications of depletion in incompatible elements, with the Kola-Karelian cratonic region showing the highest levels of depletion. Our model serves as a base to make interpretations on the enigmatic paleotectonic history of the North-Atlantic region.

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

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

• Belosa, Lea; Callegaro, Sara; Meyzen, Christine M; Gaina, Carmen; Polteau, Stephane & Bizimis, Michael [Vis alle 7 forfattere av denne artikkelen] (2024). Deep Mantle Component and Continental Crust Remobilization in the Source of Vesteris Seamount, East Greenland Margin. Geochemistry Geophysics Geosystems. 25(1). doi: 10.1029/2023GC011196. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Vesteris Seamount is a large Quaternary intraplate submarine volcano in the SW Greenland Sea, about 1,000 km NE of Iceland and 300 km NW of the Mohn's spreading ridge, whose mode of formation remains unsolved. We present geochemical data for new samples dredged from the Vesteris edifice, including major, trace elements and Sr‐Nd‐Pb‐Hf isotopes. The isotopic characteristics of the alkaline lavas, covering the basanite/tephrite to benmoreite range, indicate the involvement of depleted and enriched mantle components. The source is dominated by the depleted mantle (85%–90%) and a deep enriched component possibly supplied by the Iceland Plume (IP) (10%–15%). Additional source enrichment was due to recycled crust and sub‐continental lithospheric mantle, as suggested by Hf isotopes (0.283147 ± 0.000005) measured for the first time in Vesteris lavas and by a decoupling in Pb isotopes evidenced by relatively low‐radiogenic 207 Pb/ 204 Pb (15.510) and high‐radiogenic 208 Pb/ 204 Pb (38.554) with respect to the Northern Hemisphere Reference Line. We interpret the geochemical results using existing knowledge about the regional lithospheric and upper mantle structure. Our findings suggest that a deep (ca. 420–320 km) mantle anomaly, with seismological characteristics of the Iceland mantle plume, extends from East Greenland to the north of Jan Mayen Fracture Zone. The regional lithospheric thinning toward the Greenland Basin enabled the melting events that produced the Vesteris seamount. This lateral NNE‐directed flow lobe of the Iceland plume may have carved and transferred enriched components from the continental lithospheric margin of Greenland north of Scoresby Sund toward the Vesteris source.

• Neukirch, Maik; Minakov, Alexander; Smirnov, Maxim; Gaina, Carmen; Munteanu, Ioan & Panea, Ionelia (2024). Electrical Resistivity Imaging of the Northeast Carpathian Volcanic Arc With 3-D Magnetotellurics Reveals Shallow Hydrothermal System. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 129(7). doi: 10.1029/2023JB028230. Fulltekst i vitenarkiv Vis sammendrag

  The Carpathian belt is one of Europe's major metallogenic provinces, where magmatic ore mineralization is associated with the past subduction environment. The upper crust is mapped for the first time in the Northeast Carpathian Volcanic Arc using magnetotelluric data inversion. The obtained 3-D electrical resistivity model is interpreted in conjunction with geological information and magnetic anomaly data. The model illustrates the deep magmatic plumbing system including kilometer-scale plutonic bodies at a depth of 2–7 km. The model implies that the transport of magma and fluids in the uppermost crust was controlled by pre-existing faults and décollement horizons. Present ore mineralization, mined since historical times, can be attributed to an electrically conductive conduit that is mapped from the surface to a depth of about 30 km. It is suggested that this conduit connected a shallow magmatic chamber to a deep source region in the southeast during late Miocene time. An observed northwest deflection of the deep magmatic conduit at a depth of more than 10 km may explain the spatial gap in the distribution of the Miocene volcanic activity along the Eastern Carpathians.

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

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

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

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

• Murphy, David; Moore, Tim A.; Amijaya, D. Hendra; Anggara, Ferian; Friederich, Mike & Gaina, Carmen [Vis alle 9 forfattere av denne artikkelen] (2024). Constraints from lamprophyre petrogenesis on the timing of Eocene lithospheric thinning and associated rifting of Borneo and Sulawesi. Journal of Asian Earth Sciences. ISSN 1367-9120. 260. doi: 10.1016/j.jseaes.2023.105952. Fulltekst i vitenarkiv Vis sammendrag

  The petrogenetic history of well characterised magmatic rocks may contain invaluable information of paleo-lithospheric thickness and structure that can inform on tectonic evolution. Petrographically distinctive rocks, such as lamprophyres, provide temporal and spatial constraints to build, assess, and verify tectonic models. An alkaline lamprophyre dyke that intrudes the rift-related sediments of the Eocene Tanjung Formation of the Senakin Peninsula in South Kalimantan, Indonesia has been investigated using petrology, whole rock geochemistry and Ar-Ar geochronology. The Senakin lamprophyre dyke is mostly geochemically homogenous but petrographically stratified with vesicle free monchiquite alkaline lamprophyre mineralogy at the base and an amygdale bearing kaersutite phenocryst free upper zone. The major and trace element chemistry is consistent with an intra-plate Ocean Island Basalt like affinity. 40Ar/39Ar dating of hornblende and groundmass aliquots indicates an emplacement age of 37.45 ± 0.10 Ma (2σ), which is consistent with the Late Eocene age of the Tanjung Formation derived from microfossil analysis. The petrology and geochemistry of the Senakin lamprophyre dyke is consistent with magma genesis at > 2GPa beneath a thick lithosphere followed by fractional crystallisation at Moho depths equivalent to 0.5–0.8 GPa. This indicates a much thicker southeastern Kalimantan paleo-lithosphere. Lamprophyre magmatism was initiated by lithospheric extension associated with the opening of the Makassar Strait and also regional thermal upwelling. This extension continued to thin the lithosphere to its current thickness equivalent to 0.5 GPa.

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

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

• Panea, Ionelia; Munteanu, Ioan; Gaina, Carmen; Mocanu, Victor; Roban, Relu Dumitru & Bouaru, Catalin Florin (2023). Miocene tectonic activity at the boundary between NE Pannonian and NW Transylvanian basins (Romania): Insight from new seismic data. Terra Nova. ISSN 0954-4879. 35(6), s. 542–551. doi: 10.1111/ter.12677. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Situated at the junction between the Eastern Carpathians Mountains, the Pannonian and the Transylvanian basins, the Baia Mare region (Romania) has a complex geological history that witnessed the interaction among the three main tectonic provinces. Here, we report results from new seismic reflection measurements that provide modern information about the subsurface geological structure. The integrated analysis of the newly acquired and vintage seismic reflection data from the study area reveals details about the architecture of the Palaeogene and the Neogene deposits at the contact between the northeastern Pannonian and northwestern Transylvanian basins. In particular, it unveils a fault zone that most probably controlled the tectonic evolution of the eastern Pannonian and Transylvanian basins. A better understanding of the crustal structure and tectonic features in the study area is a first step into evaluating the geothermal potential of the region.

• Blischke, Anett; Brandsdóttir, Bryndís; Stoker, Martyn S.; Gaina, Carmen; Erlendsson, Ögmundur & Tegner, Christian Maughan [Vis alle 12 forfattere av denne artikkelen] (2022). Seismic Volcanostratigraphy: The Key to Resolving the Jan Mayen Microcontinent and Iceland Plateau Rift Evolution. Geochemistry Geophysics Geosystems. 23(4). doi: 10.1029/2021GC009948. Fulltekst i vitenarkiv Vis sammendrag

  Volcanostratigraphic and igneous province mapping of the Jan Mayen microcontinent (JMMC) and Iceland Plateau Rift (IPR) region have provided new insight into the development of rift systems during breakup processes. The microcontinent's formation involved two breakup events associated with seven distinct tectono-magmatic phases (∼63–21 Ma), resulting in a fan-shaped JMMC-IPR igneous domain. Primary structural trends and anomalous magmatic activity guided initial opening (∼63–56 Ma) along a SE-NW trend from the European margin and along a WNW-ESE trend from East Greenland. The eastern margin of the microcontinent formed during the first breakup (∼55–53 Ma), with voluminous subaerial volcanism and emplacement of multiple sets of SSW–NNE-aligned seaward-dipping reflector sequences. The more gradual, second breakup (∼52–23 Ma) consisted of four northwestward migrating IPR (I–IV) rift zones along the microcontinent's southern and western margins. IPR I and II (∼52–36 Ma) migrated obliquely into East Greenland, interlinked via segments of the Iceland-Faroe Fracture Zone, in overlapping sub-aerial and sub-surface igneous formations. IPR III and IV (∼35–23 Ma) formed a wide igneous domain south and west of the microcontinent, accompanied by uplift, regional tilting, and erosion as the area moved closer to the Iceland hotspot. The proto-Kolbeinsey Ridge formed at ∼22–21 Ma and connected to the Reykjanes Ridge via the Northwest Iceland Rift Zone, near the center of the hotspot. Eastward rift transfers, toward the proto-Iceland hotspot, commenced at ∼15 Ma, marking the initiation of segmented rift zones comparable to present-day Iceland.

• Straume, Eivind Olavson; Nummelin, Aleksi Henrynpoika; Gaina, Carmen & Nisancioglu, Kerim Hestnes (2022). Climate transition at the Eocene-Oligocene influenced by bathymetric changes to the Atlantic-Arctic oceanic gateways. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 119(17). doi: 10.1073/pnas.2115346119. Fulltekst i vitenarkiv Vis sammendrag

  The Eocene–Oligocene Transition (∼33.9 Ma) marks the largest step transformation within the Cenozoic cooling trend and is characterized by a sudden growth of the Antarctic ice sheets, cooling of the interior ocean, and the establishment of strong meridional temperature gradients. Here we examine the climatic impact of oceanic gateway changes at the Eocene–Oligocene Transition by implementing detailed paleogeographic reconstructions with realistic paleobathymetric models for the Atlantic–Arctic basins in a state-of-the-art earth system model (the Norwegian Earth System Model [NorESM-F]). We demonstrate that the warm Eocene climate is highly sensitive to depth variations of the Greenland–Scotland Ridge and the proto–Fram Strait as they control the freshwater leakage from the Arctic to the North Atlantic. Our results, and proxy evidence, suggest that changes in these gateways controlled the ocean circulation and played a critical role in the growth of land-based ice sheets, alongside CO2-driven global cooling. Specifically, we suggest that a shallow connection between the Arctic and North Atlantic restricted the southward flow of fresh surface waters during the Late Eocene allowing for a North Atlantic overturning circulation. Consequently, the Southern Hemisphere cooled by several degrees paving the way for the glaciation of Antarctica. Shortly after, the connection to the Arctic deepened due to weakening dynamic support from the Iceland Mantle Plume. This weakened the North Atlantic overturning and cooled the Northern Hemisphere, thereby promoting glaciations there. Our study points to a controlling role of the Northeast Atlantic gateways and decreasing atmospheric CO2 in the onset of glaciations in both hemispheres.

• Celli, Nicolas Luca; Lebedev, Sergei; Schaeffer, Andrew & Gaina, Carmen (2021). The tilted Iceland Plume and its effect on the North Atlantic evolution and magmatism. Earth and Planetary Science Letters. ISSN 0012-821X. 569. doi: 10.1016/j.epsl.2021.117048. Fulltekst i vitenarkiv
• Minakov, Alexander & Gaina, Carmen (2021). Probabilistic Linear Inversion of Satellite Gravity Gradient Data Applied to the Northeast Atlantic. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 126(12). doi: 10.1029/2021JB021854. Fulltekst i vitenarkiv Vis sammendrag

  We explore the mantle density structure of the northeast Atlantic region using constrained linear inversion of the satellite gravity gradient data based on statistical prior information and assuming a Gaussian model. The uncertainty of the residual gravity gradient signal is characterized by a covariance matrix obtained using geostatistical analysis of controlled-source seismic data. The forward modeling of the gravity gradients in the 3D reference crustal model is performed using a global spherical harmonics analysis. We estimate the model covariance function in the radial and angular directions using a variogram method. We compute volumetric gravity gradient kernels for a spherical shell covering the northeast Atlantic region down to the mantle transition zone (410 km depth). The solution of the linear inverse problem in the form of the mean density model and the posterior covariance matrix follows a least squares approach. The results indicate that on average the seismic velocity variation is proportional to the density variation in the northeast Atlantic region. However, a noticeable mismatch or anti-correlation exists in some areas, such as the Greenland-Iceland-Faroe ridge and southwestern Norway. The predicted low-density anomalies at depths of 100–150 km underneath the northeast Atlantic Ocean are correlated with the distribution of Cenozoic submarine volcanoes and seamount-like features of the seafloor.

• Hinsbergen, Douwe J.J. van; Steinberger, Bernhard; Guilmette, Carl; Maffione, Marco; Gurer, Derya & Peters, Kalijn [Vis alle 12 forfattere av denne artikkelen] (2021). A record of plume-induced plate rotation triggering subduction initiation. Nature Geoscience. ISSN 1752-0894. 14, s. 626–630. doi: 10.1038/s41561-021-00780-7. Fulltekst i vitenarkiv Vis sammendrag

  The formation of a global network of plate boundaries surrounding a mosaic of lithospheric fragments was a key step in the emergence of Earth’s plate tectonics. So far, propositions for plate boundary formation are regional in nature; how plate boundaries are created over thousands of kilometres in geologically short periods remains elusive. Here we show from geological observations that a >12,000-km-long plate boundary formed between the Indian and African plates around 105 Myr ago. This boundary comprised subduction segments from the eastern Mediterranean region to a newly established India–Africa rotation pole in the west Indian Ocean, where it transitioned into a ridge between India and Madagascar. We identify coeval mantle plume rise below Madagascar–India as the only viable trigger of this plate rotation. For this, we provide a proof of concept by torque balance modelling, which reveals that the Indian and African cratonic keels were important in determining plate rotation and subduction initiation in response to the spreading plume head. Our results show that plumes may provide a non-plate-tectonic mechanism for large-plate rotation, initiating divergent and convergent plate boundaries far away from the plume head. We suggest that this mechanism may be an underlying cause of the emergence of modern plate tectonics.

• Magni, Valentina; Naliboff, John; Prada, Manel & Gaina, Carmen (2021). Ridge jumps and mantle exhumation in back-arc basins. Geosciences. 11(11). doi: 10.3390/geosciences11110475. Fulltekst i vitenarkiv Vis sammendrag

  Back-arc basins in continental settings can develop into oceanic basins, when extension lasts long enough to break up the continental lithosphere and allow mantle melting that generates new oceanic crust. Often, the basement of these basins is not only composed of oceanic crust, but also of exhumed mantle, fragments of continental crust, intrusive magmatic bodies, and a complex mid-ocean ridge system characterised by distinct relocations of the spreading centre. To better understand the dynamics that lead to these characteristic structures in back-arc basins, we performed 2D numerical models of continental extension with asymmetric and time-dependent boundary conditions that simulate episodic trench retreat. We find that, in all models, episodic extension leads to rift and/or ridge jumps. In our parameter space, the length of the jump ranges between 1 and 65 km and the timing necessary to produce a new spreading ridge varies between 0.4 and 7 Myr. With the shortest duration of the first extensional phase, we observe a strong asymmetry in the margins of the basin, with the margin further from trench being characterised by outcropping lithospheric mantle and a long section of thinned continental crust. In other cases, ridge jump creates two consecutive oceanic basins, leaving a continental fragment and exhumed mantle in between the two basins. Finally, when the first extensional phase is long enough to form a well-developed oceanic basin (>35 km long), we observe a very short intra-oceanic ridge jump. Our models are able to reproduce many of the structures observed in back-arc basins today, showing that the transient nature of trench retreat that leads to episodes of fast and slow extension is the cause of ridge jumps, mantle exhumation, and continental fragments formation.

• Døssing, Arne; Gaina, Carmen; Jackson, H. Ruth & Andersen, Ole Baltazar (2020). Cretaceous ocean formation in the High Arctic. Earth and Planetary Science Letters. ISSN 0012-821X. 551. doi: 10.1016/j.epsl.2020.116552. Fulltekst i vitenarkiv
• Broek, Joost Martijn van den; Magni, Valentina; Gaina, Carmen & Buiter, Susanne (2020). The Formation of Continental Fragments in Subduction Settings: The Importance of Structural Inheritance and Subduction System Dynamics. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 125(1). doi: 10.1029/2019JB018370. Fulltekst i vitenarkiv Vis sammendrag

  Microcontinents and continental fragments are pieces of continental lithosphere, formed by extension and breakup, followed by plate boundary relocations. Microcontinents or continental fragments affiliated with passive margins are well documented, but those close to active margins are less studied. We use dynamic two‐ and three‐dimensional numerical experiments to investigate how preexisting weaknesses within a continental upper plate affect extension and the possible formation of continental fragments. Our parametric study of the configuration (width and viscosity) of this imposed weakness indicates that stress localization and breakup of the upper plate are most efficient for narrow weak zones and a viscosity contrast between the weak zone and the surrounding crust of at least 1 order of magnitude. Moreover, upper plate extension and breakup occurs only if extension has a rotational component, here caused by the presence of a continental indenter on the downgoing plate. The width of the indenter relative to oceanic part of the downgoing plate controls differential slab pull that triggers trench retreat and upper plate deformation. A downgoing plate with a relatively large continental indenter yields large enough slab rotation to detach a continental block from the overriding plate and form wide back‐arc basins. Variations in the weak zone angle with respect to the trench result in different basin geometries. We successfully modeled the first step in breakup of active continental margins and determined the settings that may facilitate microcontinent formation in a subduction framework.

• Karlsen, Krister Stræte; Domeier, Mathew; Gaina, Carmen & Conrad, Clinton Phillips (2020). A tracer-based algorithm for automatic generation of seafloor age grids from plate tectonic reconstructions. Computers & Geosciences. ISSN 0098-3004. 140. doi: 10.1016/j.cageo.2020.104508. Fulltekst i vitenarkiv Vis sammendrag

  The age of the ocean floor and its time-dependent age distribution control fundamental features of the Earth, such as bathymetry, sea level and mantle heat loss. Recently, the development of increasingly sophisticated reconstructions of past plate motions has provided models for plate kinematics and plate boundary evolution back in geological time. These models implicitly include the information necessary to determine the age of ocean floor that has since been lost to subduction. However, due to the lack of an automated and efficient method for generating global seafloor age grids, many tectonic models, most notably those extending back into the Paleozoic, are published without an accompanying set of age models for oceanic lithosphere. Here we present an automatic, tracer-based algorithm that generates seafloor age grids from global plate tectonic reconstructions with defined plate boundaries. Our method enables us to produce novel seafloor age models for the Paleozoic’s lost ocean basins. Estimated changes in sea level based on bathymetry inferred from our new age grids show good agreement with sea level record estimations from proxies, providing a possible explanation for the peak in sea level during the assembly phase of Pangea. This demonstrates how our seafloor age models can be directly compared with observables from the geologic record that extend further back in time than the constraints from preserved seafloor. Thus, our new algorithm may also aid the further development of plate tectonic reconstructions by strengthening the links between geological observations and tectonic reconstructions of deeper time.

• Celli, Nicolas Luca; Lebedev, Sergei; Schaeffer, Andrew; Ravenna, Matteoo & Gaina, Carmen (2020). The upper mantle beneath the South Atlantic Ocean, South America and Africa from waveform tomography with massive data sets. Geophysical Journal International. ISSN 0956-540X. 221(1), s. 178–204. doi: 10.1093/gji/ggz574. Fulltekst i vitenarkiv
• Celli, Nicolas Luca; Lebedev, Sergei; Schaeffer, Andrew & Gaina, Carmen (2020). African cratonic lithosphere carved by mantle plumes. Nature Communications. 11(1). doi: 10.1038/s41467-019-13871-2. Fulltekst i vitenarkiv Vis sammendrag

  How cratons, the ancient cores of continents, evolved since their formation over 2.5 Ga ago is debated. Seismic tomography can map the thick lithosphere of cratons, but its resolution is low in sparsely sampled continents. Here we show, using waveform tomography with a large, newly available dataset, that cratonic lithosphere beneath Africa is more complex and fragmented than seen previously. Most known diamondiferous kimberlites, indicative of thick lithosphere at the time of eruption, are where the lithosphere is thin today, implying surprisingly widespread lithospheric erosion over the last 200 Ma. Large igneous provinces, attributed to deep-mantle plumes, were emplaced near all lithosphere-loss locations, concurrently with or preceding the loss. This suggests that the cratonic roots foundered once modified by mantle plumes. Our results imply that the total volume of cratonic lithosphere has decreased since its Archean formation, with the fate of each craton depending on its movements relative to plumes.

• Straume, Eivind Olavson; Gaina, Carmen; Medvedev, Sergei & Nisancioglu, Kerim Hestnes (2020). Global Cenozoic Paleobathymetry with a focus on the Northern Hemisphere Oceanic Gateways. Gondwana Research. ISSN 1342-937X. 86, s. 126–143. doi: 10.1016/j.gr.2020.05.011. Fulltekst i vitenarkiv Vis sammendrag

  The evolution of the Northern Hemisphere oceanic gateways has facilitated ocean circulation changes and may have influenced climatic variations in the Cenozoic time (66 Ma–0 Ma). However, the timing of these oceanic gateway events is poorly constrained and is often neglected in global paleobathymetric reconstructions. We have therefore re-evaluated the evolution of the Northern hemisphere oceanic gateways (i.e. the Fram Strait, Greenland–Scotland Ridge, the Central American Seaway, and the Tethys Seaway) and embedded their tectonic histories in a new global paleobathymetry and topography model for the Cenozoic time. Our new paleobathymetry model incorporates Northeast Atlantic paleobathymetric variations due to Iceland mantle plume activity, updated regional plate kinematics, and models for the oceanic lithospheric age, sediment thickness, and reconstructed oceanic plateaus and microcontinents. We also provide a global paleotopography model based on new and previously published regional models. In particular, the new model documents important bathymetric changes in the Northeast Atlantic and in the Tethys Seaway near the Eocene–Oligocene transition (~34 Ma), the time of the first glaciations of Antarctica, believed to be triggered by the opening of the Southern Ocean gateways (i.e. the Drake Passage and the Tasman Gateway) and subsequent Antarctic Circumpolar Current initiation. Our new model can be used to test whether the Northern Hemisphere gateways could have also played an important role modulating ocean circulation and climate at that time. In addition, we provide a set of realistic global bathymetric and topographic reconstructions for the Cenozoic time at one million-year interval for further use in paleo-ocean circulation and climate models.

• Mandea, Mioara; Gaina, Carmen & Lesur, Vincent (2020). Magnetic Modeling, Theory, and Computation. Encyclopedia of Earth Sciences Series. ISSN 1388-4360. s. 1–15. doi: 10.1007/978-3-030-10475-7_232-1. Fulltekst i vitenarkiv
• Gaina, Carmen & Whittaker, Joanne (2020). Microcontinents. Encyclopedia of Earth Sciences Series. ISSN 1388-4360. 4, s. 1–5. doi: 10.1007/978-3-030-10475-7_240-1. Fulltekst i vitenarkiv
• Broek, Joost Martijn van den & Gaina, Carmen (2020). Microcontinents and Continental Fragments Associated With Subduction Systems. Tectonics. ISSN 0278-7407. 39(8). doi: 10.1029/2020TC006063. Fulltekst i vitenarkiv Vis sammendrag

  Microcontinents and continental fragments are small pieces of continental crust that are surrounded by oceanic lithosphere. Although classically associated with passive margin formation, here we present several preserved microcontinents and continental fragments associated with subduction systems. They are located in the Coral Sea, South China Sea, central Mediterranean and Scotia Sea regions, and a “proto‐microcontinent,” in the Gulf of California. Reviewing the tectonic history of each region and interpreting a variety of geophysical data allows us to identify parameters controlling the formation of microcontinents and continental fragments in subduction settings. All these tectonic blocks experienced long, complex tectonic histories with an important role for developing inherited structures. They tend to form in back‐arc locations and separate from their parent continent by oblique or rotational kinematics. The separated continental pieces and associated marginal basins are generally small and their formation is quick (<50 Myr). Microcontinents and continental fragments formed close to large continental masses tend to form faster than those created in systems bordered by large oceanic plates. A common triggering mechanism for their formation is difficult to identify, but seems to be linked with rapid changes of complex subduction dynamics. The young ages of all contemporary pieces found in situ suggest that microcontinents and continental fragments in these settings are short lived. Although presently the amount of in‐situ subduction‐related microcontinents is meager (an area of 0.56% and 0.28% of global, non‐cratonic, continental crustal area and crustal volume, respectively), through time microcontinents contributed to terrane amalgamation and larger continent formation.

• Straume, Eivind Olavson; Gaina, Carmen; Medvedev, Sergei; Hochmuth, Karsten; Gohl, Karsten & Whittaker, Joanne M. [Vis alle 9 forfattere av denne artikkelen] (2019). GlobSed: Updated Total Sediment Thickness in the World's Oceans. Geochemistry Geophysics Geosystems. 20(4), s. 1756–1772. doi: 10.1029/2018GC008115. Fulltekst i vitenarkiv Vis sammendrag

  We present GlobSed, a new global 5‐arc‐minute total sediment thickness grid for the world's oceans and marginal seas. GlobSed covers a larger area than previously published global grids and incorporates updates for the NE Atlantic, Arctic, Southern Ocean, and Mediterranean regions, which results in a 29.7% increase in estimated total oceanic sediment volume. We use this new global grid and a revised global oceanic lithospheric age grid to assess the relationship between the total sediment thickness and age of the underlying oceanic lithosphere and its latitude. An analytical approximation model is used to mathematically describe sedimentation trends in major oceanic basins and to allow paleobathymetric reconstructions at any given geological time. This study provides a much‐needed update of the sediment thickness distribution of the world oceans and delivers a model for sedimentation rates on oceanic crust through time that agrees well with selected drill data used for comparison.

• Khudoley, Andrey K.; Sobolev, Nikolai N.; Petrov, Eugene O; Ershova, Victoria B.; Makariev, Alexander A & Makarieva, Elena V [Vis alle 8 forfattere av denne artikkelen] (2019). A reconnaissance provenance study of Triassic–Jurassic clastic rocks of the Russian Barents Sea. GFF. ISSN 1103-5897. 141(4), s. 263–271. doi: 10.1080/11035897.2019.1621372. Fulltekst i vitenarkiv
• Lebedeva-Ivanova, Nina; Gaina, Carmen; Minakov, Alexander & Kashubin, Sergey (2019). ArcCRUST: Arctic Crustal Thickness From 3‐D Gravity Inversion. Geochemistry Geophysics Geosystems. 20(7), s. 3225–3247. doi: 10.1029/2018GC008098. Fulltekst i vitenarkiv
• Torsvik, Trond Helge; Steinberger, Bernhard; Shephard, Grace; Doubrovine, Pavel; Gaina, Carmen & Domeier, Mathew [Vis alle 8 forfattere av denne artikkelen] (2019). Pacific‐Panthalassic reconstructions: Overview, errata and the way forward. Geochemistry Geophysics Geosystems. 20(7), s. 3659–3689. doi: 10.1029/2019GC008402. Fulltekst i vitenarkiv Vis sammendrag

  We have devised a new absolute Late Jurassic‐Cretaceous Pacific plate model using a fixed hot spot approach coupled with paleomagnetic data from Pacific large igneous provinces (LIPs) while simultaneously minimizing plate velocity and net lithosphere rotation (NR). This study was motivated because published Pacific plate models for the 83.5‐ to 150‐Ma time interval are variably flawed, and their use affects modeling of the entire Pacific‐Panthalassic Ocean and interpretation of its margin evolution. These flaws could be corrected, but the revised models would imply unrealistically high plate velocities and NR. We have developed three new Pacific realm models with varying degrees of complexity, but we focus on the one that we consider most realistic. This model reproduces many of the Pacific volcanic paths, modeled paleomagnetic latitudes fit well with direct observations, plate velocities and NR resulting from the model are low, and all reconstructed Pacific LIPs align along the surface‐projected margin of the Pacific large low shear wave velocity province. The emplacement of the Shatsky Rise LIP at ~144 Ma probably caused a major plate boundary reorganization as indicated by a major jump of the Pacific‐Izanagi‐Farallon triple junction and a noteworthy change of the Pacific‐Izanagi seafloor spreading direction at around chron M20 time.

• Owen-Smith, T.M.; Ganerød, Morgan; Hinsbergen, Douwe J J van; Gaina, Carmen; Ashwal, Lewis D. & Torsvik, Trond Helge (2019). Testing Early Cretaceous Africa - South America fits with new palaeomagnetic data from the Etendeka Magmatic Province (Namibia). Tectonophysics. ISSN 0040-1951. 760, s. 23–35. doi: 10.1016/j.tecto.2017.11.010. Fulltekst i vitenarkiv Vis sammendrag

  We provide an independent test for the proposed pre-breakup fits between the South American and African continental margins based on new palaeomagnetic data. In the course of modelling the opening of the South Atlantic Ocean, several reconstructions have been proposed, which correspond to different estimates of the amount of pre-drift extension in the South American and African continental margins, and amounts of displacement along intracontinental accommodation zones. The Paraná–Etendeka Large Igneous Province erupted during a brief time interval between ~ 136 and ~ 131 Ma, just prior to opening of the South Atlantic, and has magmatic products on both the African (Etendeka lavas) and South American (Paraná lavas) plates. Here we provide new palaeomagnetic constraints on the Etendeka volcanic rocks. These yield a declination of D ± ∆ Dx = 314.4 ± 7.0° and inclination of I ± ∆ Ix = − 42.7 ± 8.3° (Plat = 47.5, PLon = 88.9, K = 26.1, A95 = 6.3, n = 21). When our results are combined with another recently published dataset, we obtain an Etendeka palaeopole at 49.1° S, 87.6° E (D ± ∆ Dx = 315.9 ± 3.8°, I ± ∆ Ix = − 43.9 ± 4.4°, K = 23.4, A95 = 3.5, n = 75). We compare three recent models for South Atlantic Ocean opening, discuss which of the models best fits the palaeomagnetic data, and present a revised reconstruction for West Gondwana during the Early Cretaceous.

• Afonso, Juan Carlos; Salajegheh, Farshad; Szwillus, Wolfgang; Ebbing, Jörg & Gaina, Carmen (2019). A global reference model of the lithosphere and upper mantle from joint inversion and analysis of multiple data sets. Geophysical Journal International. ISSN 0956-540X. 217(3), s. 1602–1628. doi: 10.1093/gji/ggz094. Fulltekst i vitenarkiv
• Gaina, Carmen & Jakob, Johannes (2018). Global Eocene tectonic unrest: Possible causes and effects around the North American plate. Tectonophysics. ISSN 0040-1951. doi: 10.1016/j.tecto.2018.08.010. Fulltekst i vitenarkiv Vis sammendrag

  Many of our planet's “crises” were the result of sudden changes in plate tectonic configuration or catastrophic outbursts of volcanism caused by mantle plume impingement at the base of the lithosphere. At the Paleocene-Eocene boundary and in the Early Eocene several mantle plumes, continental collision and mid-ocean ridge subduction triggered a series of changes in seafloor spreading dynamics. We have constructed a detailed global model of oceanic lithosphere age and spreading rates for the 60 to 35 Ma interval. We revise evidence for changes in seafloor spreading direction in the North Atlantic, Arctic and NE Pacific oceans. At least two periods of spreading rate highs, which are separated by sharp value decrease, occurred along the entire eastern North American plate boundary from C25 to C18 time (c. 57 to 40 Ma). The collision and incipient subduction of the Early Eocene Siletzia oceanic LIP may have caused the sharp decrease in spreading rate at C23 time in the Labrador Sea and north of Charlie-Gibbs fracture zone. The post C23 rapid Farallon slab-break-off and subsequent upper mantle flow upwelling may have led to further variations in North Atlantic spreading rates at C22-21 time. Eastward Pacific subduction may have resumed at c. 43 Ma as indicated by a steady NE Pacific seafloor-spreading regime which resumed at or shortly after C21. The North Atlantic realm shows a delayed response to tectonic events west of North America, with an increase in spreading rate south of Charlie-Gibbs fracture zone from C20 to C18 time, followed by a steady decrease until the Oligocene. North American Late Paleocene-Early Eocene kimberlite magma that erupted more than 1000 km from its western plate boundary constitutes additional evidence that tectonic stresses due to changes in the mantle-lithosphere interactions may have affected the entire plate, and therefore also its eastern boundaries.

• Struijk, Erzsébet L.M.; Tesauro, Magdala; Lebedeva-Ivanova, Nina N.; Gaina, Carmen; Beekman, Fred & Cloetingh, Sierd A.P.L (2018). The Arctic lithosphere: Thermo-mechanical structure and effective elastic thickness. Global and Planetary Change. ISSN 0921-8181. 171, s. 2–17. doi: 10.1016/j.gloplacha.2018.07.014. Fulltekst i vitenarkiv Vis sammendrag

  For the first time, lithospheric temperatures, strength, and effective elastic thickness (Te) distributions are estimated for the Arctic region north of 68°. To this aim, we use ArcCRUST, a recent model of the Arctic crust, which includes the thickness and density of the crust and sediments, the boundaries between the continental and oceanic crust, and the age of the oceanic lithosphere. We estimate the temperature variations in the continental lithosphere assuming steady-state conditions, for a constant surface heat flow of 50 mWm−2 and 62 mWm−2 for the onshore and offshore regions, respectively. In the oceanic domain, the temperature variations are estimated adopting a global depth and heat flow model. We discuss the robustness of the results by comparing the new thermal field with temperatures obtained from inversion of a regional seismic velocity model. The results are used as input for estimating integrated strength and Te, assuming a mafic crustal rheology. Our models predict a sharp transition between cratonic areas, characterized by high strength and Te, and tectonically active areas with a weaker lithosphere, corresponding to the continental shelves and the oceanic spreading ridges. The significant lateral change in our modeled strength and Te at the edges of Greenland and Canadian Arctic and along the active mid-ocean ridge in the NE Atlantic corresponds to increased observed seismic activity.

• Ershova, Victoria; Anfinson, Owen; Prokopiev, Andrei; Khudoley, Andrei; Stockli, Daniel & Faleide, Jan Inge [Vis alle 8 forfattere av denne artikkelen] (2018). Detrital zircon (U-Th)/He ages from Paleozoic strata of the Severnaya Zemlya Archipelago: Deciphering multiple episodes of Paleozoic tectonic evolution within the Russian High Arctic. Journal of Geodynamics. ISSN 0264-3707. 119, s. 210–220. doi: 10.1016/j.jog.2018.02.007. Fulltekst i vitenarkiv Vis sammendrag

  Combined (U-Th)/He and U-Pb detrital zircon geochronological data are reported from Ordovician to Devonian strata of the Severnaya Zemlya archipelago to address the paleogeography of the Kara Terrane in the Russian High Arctic. (U-Th)/He ages from all six samples analyzed were not reset after sediment deposition, indicating that detrital zircons carry information on the exhumation history in the source region of the clastic material. In Ordovician-Silurian strata, (U-Th)/He ages range from 583.8 ± 46.7 to 429.0 ± 34.3 Ma. These ages nicely coincide with significant regional exhumation during the Caledonian and Timanian orogenies. In addition, combined U-Pb and (U-Th)/He dating show that within the source region, zircons that were crystalized during the Timanian Orogeny (U-Pb ages 680–560 Ma) were likely exhumed during younger Caledonian events ((U-Th)/He ages of 455–495 Ma), suggesting potential overlap of these orogens within the source region. In Devonian strata, detrital zircon (U-Th)/He ages range from 517.2 ± 41.38 to 332.9 ± 26.6 Ma, with a peak age of ca. 375 Ma. This 375 Ma event may be correlated with either the Ellesmerian Orogeny or the terminal Solundian/Svalbardian stages of the Caledonian Orogeny.

• Nikishin, AM; Gaina, Carmen; Petrov, E.I.; Malyshev, NA & Freiman, SI (2018). Eurasia Basin and Gakkel Ridge, Arctic Ocean: Crustal asymmetry, ultra-slow spreading and continental rifting revealed by new seismic data. Tectonophysics. ISSN 0040-1951. 746, s. 64–82. doi: 10.1016/j.tecto.2017.09.006. Fulltekst i vitenarkiv Vis sammendrag

  High Arctic new seismic data, collected by Russian Federation from 2011 to 2014, and additional geological and geophysical information, are used to interpret the basement and sedimentary structure of central and eastern Eurasia Basin, the Gakkel Ridge, and their transition into the Laptev Sea. We find that significant changes in basement topography occur in Nansen Basin at C20 (43.43 Ma) and in the Amundsen basins at C21 (45.7 Ma), and in both basins at C13 (33 Ma). A long seismic profile, that documents for the first time the structure of conjugate flanks and their margins in the central-eastern Eurasia Basin, confirms that oceanic accretion was asymmetric, with 10% less crust developed in the Amundsen Basin since continental break-up. In the eastern Amundsen Basin, we observe mid-ocean ridge uplift since C13 (33 Ma). We identify four distinct sedimentary packages in the Eurasia Basin: Early to Mid Eocene (c. 56 to 45.7 Ma), Mid Eocene to Early Oligocene (45.7 to 33.2 Ma), Early Oligocene to Early Miocene (33.2 to 19.7) and Early Miocene to Present (19.7 to 0 Ma); they are linked to the oceanic lithosphere age determined from magnetic data. The deepest part of the Gakkel Ridge (5215 m), situated close to the easternmost part of this mid ocean ridge, is imaged for the first time by seismic data that reveals volcanic constructions within the older axial ridges and on the flanks. Gakkel Ridge's asymmetric flanks with shallow, regularly-spaced, and rugged structure, typical to ultra-slow spreading ridges, imply periodicity of tectonic phases. The Khatanga-Lomonosov Fault between Lomonosov Ridge and the Laptev Sea region, is identified on few seismic profiles; kinematic models predict that it may have been active only for a maximum of 10 myr after continental break-up.

• Døssing, Arne; Gaina, Carmen & Brozena, J.M. (2017). Building and breaking a large igneous province: An example from the High Arctic. Geophysical Research Letters. ISSN 0094-8276. 44(12), s. 6011–6019. doi: 10.1002/2016GL072420. Fulltekst i vitenarkiv Vis sammendrag

  The genesis of the Amerasia Basin in the Arctic Ocean has been difficult to discern due to overprint of the Cretaceous High‐Arctic Large Igneous Province (HALIP). Based on detailed analysis of bathymetry data, new Arctic magnetic and gravity compilations, and recently published radiometric and seismic data, we present a revised plate kinematic model of the northernmost Amerasia Basin. We show that the smaller Makarov Basin is formed by rifting and seafloor spreading during the latest Cretaceous (to middle Paleocene). The opening progressively migrated into the Alpha Ridge structure, which was the focus of Early‐to‐Middle Cretaceous HALIP formation, causing breakup of the proto‐Alpha Ridge into the present‐day Alpha Ridge and Alpha Ridge West Plateau. We propose that breakup of the Makarov Basin was triggered by extension between the North America and Eurasian plates and possibly North Pacific plate rollback.

• Blischke, A; Gaina, Carmen; Hopper, J.R.; Péron-Pinvidic, Gwenn; Brandsdóttir, Bryndís & Guarnieri, P [Vis alle 8 forfattere av denne artikkelen] (2017). The Jan Mayen microcontinent: an update of its architecture, structural development and role during the transition from the Ægir Ridge to the mid-oceanic Kolbeinsey Ridge. Geological Society Special Publication. ISSN 0305-8719. 447, s. 299–337. doi: 10.1144/SP447.5. Fulltekst i vitenarkiv Vis sammendrag

  We present a revised tectonostratigraphy of the Jan Mayen microcontinent (JMMC) and its southern extent, with the focus on its relationship to the Greenland–Iceland–Faroe Ridge area and the Faroe–Iceland Fracture Zone. The microcontinent's Cenozoic evolution consists of six main phases corresponding to regional stratigraphic unconformities. Emplacement of Early Eocene plateau basalts at pre-break-up time (56–55 Ma), preceded the continental break-up (55 Ma) and the formation of seawards-dipping reflectors (SDRs) along the eastern and SE flanks of the JMMC. Simultaneously with SDR formation, orthogonal seafloor spreading initiated along the Ægir Ridge (Norway Basin) during the Early Eocene (C24n2r, 53.36 Ma to C22n, 49.3 Ma). Changes in plate motions at C21n (47.33 Ma) led to oblique seafloor spreading offset by transform faults and uplift along the microcontinent's southern flank. At C13n (33.2 Ma), spreading rates along the Ægir Ridge started to decrease, first south and then in the north. This was probably complemented by intra-continental extension within the JMMC, as indicated by the opening of the Jan Mayen Basin – a series of small pull-apart basins along the microcontinent's NW flank. JMMC was completely isolated when the mid-oceanic Kolbeinsey Ridge became fully established and the Ægir Ridge was abandoned between C7 and C6b (24–21.56 Ma).

• Gaina, Carmen; Blischke, Anett; Geissler, Wolfram H.; Kimbell, Geoffrey S & Erlendsson, Ögmundur (2017). Seamounts and oceanic igneous features in the NE Atlantic: A link between plate motions and mantle dynamics. Geological Society Special Publication. ISSN 0305-8719. 447, s. 419–442. doi: 10.1144/SP447.6. Fulltekst i vitenarkiv Vis sammendrag

  A new regional compilation of seamount-like oceanic igneous features (SOIFs) in the NE Atlantic points to three distinct oceanic areas of abundant seamount clusters. Seamounts on oceanic crust dated 54–50 Ma are formed on smooth oceanic basement, which resulted from high spreading rates and magmatic productivity enhanced by higher than usual mantle plume activity. Late Eocene–Early Miocene SOIF clusters are located close to newly formed tectonic features on rough oceanic crust in the Irminger, Iceland and Norway basins, reflecting an unstable tectonic regime prone to local readjustments of mid-ocean ridge and fracture zone segments accompanied by extra igneous activity. A SOIF population observed on Mid-Miocene–Present rough oceanic basement in the Greenland and Lofoten basins, and on conjugate Kolbeinsey Ridge flanks, coincides with an increase in spreading rate and magmatic productivity. We suggest that both tectonic/kinematic and magmatic triggers produced Mid-Miocene–Present SOIFs, but the Early Miocene westwards ridge relocation may have played a role in delaying SOIF formation south of the Jan Mayen Fracture Zone. We conclude that Iceland plume episodic activity combined with regional changes in relative plate motion led to local mid-ocean ridge readjustments, which enhanced the likelihood of seamount formation.

• Geissler, Wolfram H.; Gaina, Carmen; Hopper, John R.; Funck, Thomas; Blischke, Anett & Árting, Uni Egholm [Vis alle 9 forfattere av denne artikkelen] (2017). Seismic volcanostratigraphy of the NE Greenland continental margin. Geological Society Special Publication. ISSN 0305-8719. 447, s. 149–170. doi: 10.1144/SP447.11. Fulltekst i vitenarkiv Vis sammendrag

  The Early Eocene continental break-up between the NE Greenland and the mid-Norwegian–SW Barents Sea margins was associated with voluminous magmatism and led to the emplacement of massive volcanic complexes including wedges of seawards-dipping reflections (SDR). We study the distribution of these break-up-related volcanic rocks along the NE Greenland margin by revisiting existing seismic reflection data and comparing our observations to better-studied segments of the conjugate margin. Seismic facies types match between the conjugate margins and show strong lateral variations. Seaward-dipping wedges are mapped offshore East Greenland, the conjugate to the Vøring continental margin. The geophysical signature of the SDRs becomes less visible towards the north, as it does along the conjugate Lofoten–Vesterålen margin. We suggest that the Traill Ø volcanic ridge is a result of plume–ridge interactions formed between approximately 54 and 47 Ma. North of the East Greenland Ridge, strong basement reflections conjugate to the Vestbakken Volcanic Province are interpreted as lava flows or ‘spurious’ SDRs. We discuss our findings in conjunction with results from seismic wide-angle experiments, gravity and magnetic data. We focus on the spatial and temporal relationships of the break-up volcanic rocks, and their structural setting in a late rift and initial oceanic drift stage.

• Domeier, Mathew; Shephard, Grace; Jakob, Johannes; Gaina, Carmen; Doubrovine, Pavel & Torsvik, Trond Helge (2017). Intraoceanic subduction spanned the Pacific in the Late Cretaceous–Paleocene. Science Advances. 3(11). doi: 10.1126/sciadv.aao2303. Fulltekst i vitenarkiv Vis sammendrag

  The notorious ~60° bend separating the Hawaiian and Emperor chains marked a prominent change in the motion of the Pacific plate at ~47 Ma (million years ago), but the origin of that change remains an outstanding controversy that bears on the nature of major plate reorganizations. Lesser known but equally significant is a conundrum posed by the pre-bend (~80 to 47 Ma) motion of the Pacific plate, which, according to conventional plate models, was directed toward a fast-spreading ridge, in contradiction to tectonic forcing expectations. Using constraints provided by seismic tomography, paleomagnetism, and continental margin geology, we demonstrate that two intraoceanic subduction zones spanned the width of the North Pacific Ocean in Late Cretaceous through Paleocene time, and we present a simple plate tectonic model that explains how those intraoceanic subduction zones shaped the ~80 to 47 Ma kinematic history of the Pacific realm and drove a major plate reorganization.

• Stoker, Martyn S.; Stewart, Margaret A.; Shannon, Patrick M.; Bjerager, Morten; Nielsen, Tove & Blischke, Anett [Vis alle 10 forfattere av denne artikkelen] (2017). An overview of the Upper Palaeozoic-Mesozoic stratigraphy of the NE Atlantic region. Geological Society Special Publication. ISSN 0305-8719. 447, s. 11–68. doi: 10.1144/SP447.2. Fulltekst i vitenarkiv Vis sammendrag

  This study describes the distribution and stratigraphic range of the Upper Palaeozoic–Mesozoic succession in the NE Atlantic region, and is correlated between conjugate margins and along the axis of the NE Atlantic rift system. The stratigraphic framework has yielded important new constraints on the timing and nature of sedimentary basin development in the NE Atlantic, with implications for rifting and the break-up of the Pangaean supercontinent. From a regional perspective, the Permian–Triassic succession records a northwards transition from an arid interior to a passively subsiding, mixed carbonate–siliciclastic shelf margin. A Late Permian–earliest Triassic rift pulse has regional expression in the stratigraphic record. A fragmentary paralic to shallow-marine Lower Jurassic succession reflects Early Jurassic thermal subsidence and mild extensional tectonism; this was interrupted by widespread Mid-Jurassic uplift and erosion, and followed by an intense phase of Late Jurassic rifting in some (but not all) parts of the NE Atlantic region. The Cretaceous succession is dominated by thick basinal-marine deposits, which accumulated within and along a broad zone of extension and subsidence between Rockall and NE Greenland. There is no evidence for a substantive and continuous rift system along the proto-NE Atlantic until the Late Cretaceous.

• Torsvik, Trond Helge; Doubrovine, Pavel; Steinberger, Bernhard; Gaina, Carmen; Spakman, Wim & Domeier, Mathew (2017). Pacific plate motion change caused the Hawaiian-Emperor Bend. Nature Communications. 8. doi: 10.1038/ncomms15660. Fulltekst i vitenarkiv Vis sammendrag

  A conspicuous 60° bend of the Hawaiian-Emperor Chain in the north-western Pacific Ocean has variously been interpreted as the result of an abrupt Pacific plate motion change in the Eocene (∼47 Ma), a rapid southward drift of the Hawaiian hotspot before the formation of the bend, or a combination of these two causes. Palaeomagnetic data from the Emperor Seamounts prove ambiguous for constraining the Hawaiian hotspot drift, but mantle flow modelling suggests that the hotspot drifted 4–9° south between 80 and 47 Ma. Here we demonstrate that southward hotspot drift cannot be a sole or dominant mechanism for formation of the Hawaiian-Emperor Bend (HEB). While southward hotspot drift has resulted in more northerly positions of the Emperor Seamounts as they are observed today, formation of the HEB cannot be explained without invoking a prominent change in the direction of Pacific plate motion around 47 Ma.

• Péron-Pinvidic, Gwenn; Hopper, John R.; Stoker, Martyn; Gaina, Carmen; Funck, Thomas & Árting, Uni Egholm [Vis alle 7 forfattere av denne artikkelen] (2017). The NE Atlantic region: A reappraisal of crustal structure, tectonostratigraphy and magmatic evolution - An introduction to the NAG-TEC project. Geological Society Special Publication. ISSN 0305-8719. 447, s. 1–9. doi: 10.1144/SP447.17. Fulltekst i vitenarkiv Vis sammendrag

  The NE Atlantic region and its continental margins (Fig. 1) hold unique information for understanding many aspects of Earth science, from global geodynamics to palaeoceanography and global environmental change. It also holds some of the world's most important hydrocarbon reserves from the North Sea, along the Atlantic margins of Ireland, Britain and Norway, and into the Arctic in the Barents Sea. Historically, studies in the NE Atlantic were important for establishing many of the key ideas during the early part of the plate tectonic revolution. Linear magnetic anomalies along the Reykjanes Ridge were identified as early as in the 1960s (Heirtzler et al. 1966) and provided strong evidence for the seafloor spreading hypothesis (Dietz 1961), which by then had been established as a new and holistic theory (Ewing & Heezen 1956). At the same time, Iceland was already recognized as an intriguing anomalous entity (Böðvarsson & Walker 1964) and contributed to knowledge about how Earth's magnetic field reversed its polarity through time. The fact that rifting occurs in close association with old sutures and orogenic belts led Wilson to propose that the Atlantic Ocean closed and opened again, establishing the concept of the ‘Wilson tectonic cycle’ (Wilson 1966; Dewey 1969). The North Atlantic continental margins have long been considered as archetypal, and divergent margins world-wide are commonly described as ‘Atlantic-type passive margins’. However, it is now accepted that these so-called ‘passive’ margins remain dynamic long after break-up, including post-rift vertical movements of up to kilometre scale. The type examples for such epeirogenic movements being, once again, the North Atlantic margins (Praeg et al. 2005).

• Ershova, Victoria B.; Prokopiev, Andrei V.; Sobolev, Nikolai N.; Petrov, EO; Khudoley, Andrey K. & Faleide, Jan Inge [Vis alle 8 forfattere av denne artikkelen] (2017). New data on the basement of Franz Josef Land, Arctic region. Geotectonics. ISSN 0016-8521. 51(2), s. 121–130. doi: 10.1134/S0016852117020030. Fulltekst i vitenarkiv
• Gaina, Carmen; Nasuti, Aziz; Kimbell, Geoffrey S & Blischke, Anett (2017). Break-up and seafloor spreading domains in the NE Atlantic. Geological Society Special Publication. ISSN 0305-8719. 447, s. 393–417. doi: 10.1144/SP447.12. Fulltekst i vitenarkiv Vis sammendrag

  An updated magnetic anomaly grid of the NE Atlantic and an improved database of magnetic anomaly and fracture zone identifications allow the kinematic history of this region to be revisited. At break-up time, continental rupture occurred parallel to the Mesozoic rift axes in the south, but obliquely to the previous rifting trend in the north, probably due to the proximity of the Iceland plume at 57–54 Ma. The new oceanic lithosphere age grid is based on 30 isochrons (C) from C24n old (53.93 Ma) to C1n old (0.78 Ma), and documents ridge reorganizations in the SE Lofoten Basin, the Jan Mayen Fracture Zone region, in Iceland and offshore Faroe Islands. Updated continent–ocean boundaries, including the Jan Mayen microcontinent, and detailed kinematics of the Eocene–Present Greenland–Eurasia relative motions are included in this model. Variations in the subduction regime in the NE Pacific could have caused the sudden northwards motion of Greenland and subsequent Eurekan deformation. These events caused seafloor spreading changes in the neighbouring Labrador Sea and a decrease in spreading rates in the NE Atlantic. Boundaries between major oceanic crustal domains were formed when the European Plate changed its absolute motion direction, probably caused by successive adjustments along its southern boundary.

• Shephard, Grace Elizabeth; Trønnes, Reidar G; Spakman, Wim; Panet, Isabelle & Gaina, Carmen (2016). Evidence for slab material under Greenland and links to Cretaceous High Arctic magmatism. Geophysical Research Letters. ISSN 0094-8276. 43(8), s. 3717–3726. doi: 10.1002/2016GL068424. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Peron-Pinvidic, Gwenn; Hopper, John R.; Stoker, Martyn; Gaina, Carmen; Doornebal, Hans & Funck, Thomas [Vis alle 7 forfattere av denne artikkelen] (2017). The NE Atlantic region: A reappraisal of crustal structure, tectono-stratigraphy and magmatic evolution. Geological Society of London. ISBN 9781786202789. 460 s. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Tjoflot, Gunn Kristin; Gaina, Carmen & Minakov, Alexander (2025). Ready for the fourth and final GoNorth expedition to explore the Arctic Ocean. [Internet]. geo.uio.no. doi: https:/www.mn.uio.no/geo/english/research/news-and-events/news/2025/ready-for-the-final-gonorth-2025-expedition-to-the-arctic-sea.html. Fulltekst i vitenarkiv Vis sammendrag

  The fourth expedition to the Arctic Ocean in the GoNorth initiative took place in November–December 2025. On board was also UiO researchers Carmen Gaina and Alexander Minakov.

• Albert, Daniel; Jørgensen, Steffen Leth & Gaina, Carmen (2025). GoNorth 2025. doi: https:/vimeo.com/1148035333. Fulltekst i vitenarkiv Vis sammendrag

  Summary of the fourth and last GoNorth expedition.

• Escartín, Javier; Sautter, Benjamin; Gaina, Carmen; Petersen, Sven; Granot, Roi & Pubelier, Manuel (2025). MAPRIDGES: Geometry of global mid-ocean ridge plate boundaries, and the role of transform faults and non-transform offsets. doi: 10.5194/egusphere-egu25-18143. Fulltekst i vitenarkiv Vis sammendrag

  The global mid-ocean ridge system produces the oceanic lithosphere accounting for ~70% of the Earth&#8217;s surface, while hosting active processes (tectonic, volcanic, hydrothermal circulation). The ridge system is segmented by both transform faults and non-transform offsets, and their geometry can be now re-evaluated with existing multibeam bathymetry (with a resolution of ~100 m or better), both from publicly accessible datasets (e.g., GMRT, NCEI, Pangaea, AWI, among others) and available through published studies. This high-resolution bathymetry is now available for ~25% of the ocean seafloor, but covers a significant proportion of the global mid-ocean ridge system (>70%) and is thus suitable to refine and finely define its geometry.&#160;&#160;The MAPRIDGES database (https://doi.org/10.17882/99981) provides a global dataset that includes the newly-defined geometry of individual mid-ocean ridge segments, the most complete catalog to date of transform faults, and identifies non-transform offsets (NTOs). This effort is linked to the World 5M project by CGMW (Commission for the Geological Map of the World). We calculate the lateral offset associated with these NTOs, and determine if they correspond to overlaps of adjacent segments or if they are associated with a gap (underlap). Two different plate models (MORVEL and GSRM) are used to estimate&#160; the length of overlaps, underlaps and their links to variations in spreading direction.&#160;Our new database, gives a global, detailed view of the global mid-ocean ridge geometry, and provides the first&#160; evaluation of the overall lengths of ridges and associated lateral offsets, both transform and non-transform. Mid ocean ridge segments (1471) show a cumulative length of ~71200 km, with and along-axis distance of ~4800 km of overlapping segments, and ~1700 km of underlap; taking these offsets into account this yields a total length of along-axis segments of ~75300 km. We have also digitized the traces of 262 transform faults to obtain the most complete catalogue to date of these structures. Transform faults account for a cumulative lateral offset of ridges of ~27000 km. We report a first estimate of the lateral offset of 1058 identified NTOs at ~10400 km, accounting for >30% of the cumulative transform fault length. The resulting cumulative lateral offset from both transform and non-tranform segments is thus ~37400 km, and is ~50% of the total ridge length. As in the case of transform faults, these NTOs are associated with deformation of a significant volume of the recently accreted oceanic lithosphere, and thus likely facilitating hydrothermal circulation and alteration of the lithosphere. This study will facilitate the quantification of these processes and provides a basis to better understand their implications on local and global environments (e.g., chemical fluxes associated with alteration at all offsets).

• Shephard, Grace; Abdelmalak, Mohamed Mansour; Faleide, Jan Inge; Clennett, Edward; Gac, Sebastien & Zahirovic, Sabin [Vis alle 9 forfattere av denne artikkelen] (2025). A basin-to-plate deformable plate framework to capture the multi-phase rifting of the Northeast Atlantic. Fulltekst i vitenarkiv
• Minakov, Alexander; Klemetsdal, Øystein; Collignon, Marine; Gaina, Carmen; Panea, Ionelia & Neukirch, Maik (2024). Basin-Scale Modeling of the Baia Mare geothermal and Ore-Forming System. EarthDoc. doi: 10.3997/2214-4609.202410836. Fulltekst i vitenarkiv
• Gaina, Carmen (2023). Tracing the ocean's topographyThe Deepest MapLaura Trethewey Harper Wave, 2023. 304 pp. Science. ISSN 0036-8075. 381(6656), s. 381–381. doi: 10.1126/science.adi9346. Fulltekst i vitenarkiv
• Belosa, Lea; Gaina, Carmen; Callegaro, Sara; Mazzini, Adriano; Meyzen, Christine M & Polteau, Stephane [Vis alle 7 forfattere av denne artikkelen] (2022). Plume-Fracture Zone interactions in the NE Atlantic. Fulltekst i vitenarkiv
• Shephard, Grace; Gaina, Carmen; Heyn, Björn Holger; Conrad, Clinton Phillips; Anfinson, Owen & Schaeffer, Andrew [Vis alle 7 forfattere av denne artikkelen] (2022). Exploring potential lower mantle structures and interactions for the origins of HALIP. Fulltekst i vitenarkiv
• Shephard, Grace; Faleide, Jan Inge; Gaina, Carmen; Abdelmalak, Mohamed Mansour; Gac, Sebastien & Torsvik, Trond Helge (2022). Building deformable plate models for the Northeast Atlantic. Fulltekst i vitenarkiv
• Dombrovski, Elisaveta; Mondol, Nazmul Haque; Bohloli, Bahman; Gaina, Carmen & Torabi, Anita (2021). Monitoring ground surface and seafloor deformation caused by subsurface fluid injection. Fulltekst i vitenarkiv
• Belosa, Lea; Gaina, Carmen; Callegaro, Sara; Trønnes, Reidar G; Mazzini, Adriano & Meyzen, Christine M [Vis alle 7 forfattere av denne artikkelen] (2021). Constraining the enigmatic source of Vesteris Seamount volcanism. Fulltekst i vitenarkiv
• Gaina, Carmen; Barletta, V.; Conrad, Clinton Phillips; Ebbing, Jörg; Forsberg, R. & Ferraccioli, Fausto [Vis alle 9 forfattere av denne artikkelen] (2020). Interplay of cryosphere, solid earth and dynamic mantle in the Arctic. Fulltekst i vitenarkiv
• Gaina, Carmen; Schaeffer, A. J.; Nikishin, Anatoly; Lebedev, Sergei; Minakov, Alexander & Breyer, Florianne (2019). The crust and upper mantle of the Eurasia Basin revealed by geophysical data and mantle tomography models. Fulltekst i vitenarkiv
• Gaina, Carmen; Schaeffer, A. J.; Nikishin, Anatoly; Lebedev, Sergei & Minakov, Alexander (2019). The Crust and Upper Mantle of the Eurasia Basin Revealed by Geophysical data and Mantle Tomography Models. Fulltekst i vitenarkiv
• Gaina, Carmen; Schaeffer, A. J.; Nikishin, AM; Lebedev, Sergei & Minakov, Alexander (2019). The Crust and Upper Mantle of the Eurasia Basin Revealed by Geophysical data and Mantle Tomography Models. Fulltekst i vitenarkiv
• Ershova, Victoria; Stockli, Daniel; Khudoley, Andrey K. & Gaina, Carmen (2019). When big river started to drain to Arctic Basin: view from the Sverdrup Well (Kara Sea). Fulltekst i vitenarkiv
• Blischke, Anett; Brandsdottir, Bryndis; Erlendsson, Ögmundur; Planke, Sverre & Gaina, Carmen (2019). The Jan Mayen microcontinent and Iceland Plateau volcanic breakup margins. Fulltekst i vitenarkiv
• Shephard, Grace & Gaina, Carmen (2019). The Arctic in deep time and space - plate tectonics in the Arctic. Fulltekst i vitenarkiv
• Shephard, Grace; Abdelmalak, Mohamed Mansour; Gaina, Carmen; Faleide, Jan Inge; Torsvik, Trond Helge & Jackson, Ruth [Vis alle 9 forfattere av denne artikkelen] (2019). A Greenland centered puzzle: Updated plate reconstructions of the North Atlantic and Arctic. Fulltekst i vitenarkiv
• Shephard, Grace & Gaina, Carmen (2019). The Arctic in deep time and space: a Earth Scientist's perspective. Fulltekst i vitenarkiv
• Shephard, Grace; Crameri, Fabio & Gaina, Carmen (2019). Shifting around, digging up, and colouring in oceans. Fulltekst i vitenarkiv
• Shephard, Grace; Gaina, Carmen; Torsvik, Trond Helge & Faleide, Jan Inge (2019). Plate tectonics and mantle structure of the Arctic, North Atlantic, and Panthalassa: recent updates. Fulltekst i vitenarkiv
• Shephard, Grace; Jackson, Ruth; Gaina, Carmen; Piepjohn, Karsten; Oakey, Gordon & Li, Qingmou [Vis alle 9 forfattere av denne artikkelen] (2019). Updated tectonic reconstructions of the Cretaceous Arctic: Digital plate model and applications. Fulltekst i vitenarkiv
• Gaina, Carmen; Niocaill, Conall Mac; Conrad, Clinton Phillips; Steinberger, Bernhard & Svensen, Henrik (2019). Linking plate tectonics and volcanism to deep earth dynamics - A tribute to Trond H. Torsvik. Tectonophysics. ISSN 0040-1951. 760, s. 1–3. doi: 10.1016/j.tecto.2019.03.002. Fulltekst i vitenarkiv
• Shephard, Grace; Jackson, Ruth; Gaina, Carmen; Piepjohn, Karsten; Oakey, Gordon & Qingmou, Li [Vis alle 9 forfattere av denne artikkelen] (2019). Updated tectonic reconstructions of the Cretaceous Arctic: Digital plate model and applications. Fulltekst i vitenarkiv
• Odlum, M; Anfinson, Owen; Poulaki, E. M.; Shephard, Grace; Stockli, Daniel & Gaina, Carmen (2019). Thermal record of deformation, exhumation, and fluid-rock interactions along the Billefjorden Fault Zone, Pyramiden, Svalbard. Fulltekst i vitenarkiv
• Hopper, John R.; Fatah, Rader Abdul; Gaina, Carmen; Geissler, Wolfram H; Funck, Thomas & Kimbell, Geoffrey S [Vis alle 7 forfattere av denne artikkelen] (2019). Sediment thickness, crustal thickness, and residual topography of the North Atlantic: estimating dynamic topography around Iceland. Fulltekst i vitenarkiv
• Anfinson, Owen; Odlum, M; Shephard, Grace; Gaina, Carmen; Stockli, Daniel & Finley, Jake [Vis alle 7 forfattere av denne artikkelen] (2019). Provenance analysis of the Devonian Andrée Land Basin, Svalbard. Fulltekst i vitenarkiv
• Straume, Eivind Olavson; Gaina, Carmen & Medvedev, Sergei (2019). Cenozoic paleobathymetry of the Atlantic-Arctic oceanic gateways: Iceland plume pulsations and implications on paleo-ocean circulation. Fulltekst i vitenarkiv
• Straume, Eivind Olavson; Gaina, Carmen & Medvedev, Sergei (2019). Cenozoic Paleobathymetry of the Northern Hemisphere Oceanic Gateways: Implications for Paleo-ocean Circulation and Climate. Fulltekst i vitenarkiv
• Blischke, Anett; Brandsdottir, Bryndis; Gaina, Carmen; Stocker, Martin & Erlendsson, Ögmundur (2019). Tectono-magmatic evolution of the Jan Mayen microcontinent and Iceland plateau. Fulltekst i vitenarkiv
• Broek, Joost Martijn van den; Gaina, Carmen; Buiter, Susanne & Andersen, Torgeir Bjørge (2018). Subduction-related continental rifting and microcontinent formation. Fulltekst i vitenarkiv Vis sammendrag

  Continental rifting sometimes results in the formation of microcontinents and continental fragments. A micro- continent is a block of continental crust completely surrounded by oceanic lithosphere,. Classical examples are the Jan-Mayen Microcontinent in the NE Atlantic and the Seychelles in the Indian Ocean. A continental fragment is still attached to its parent continent by highly extended crust which failed to break-up. Examples are fragments off the west coast of Ireland associated with the opening of the NE Atlantic. Proposed scenarios for the formation of microcontinents and continental fragments are mostly associated with rifted continental margins, where rifting followed by seafloor spreading and mid-ocean-ridge relocation can result in the isolation of continental blocks and thus the formation of microcontinents. However, subduction processes can also result in microcontinent and continental fragment formation but the processes involved in their creation are not properly understood so far. Among microcontinents formed in subduction settings are the Corsica-Sardinia block in the Central Mediterranean, the Louisiade Plateau off the NE coast of Australia, and the Macclesfield and Reed Banks in the South China Sea. Using publicly available geophysical and geological data we first review the tectonic structure of micro- continents and conjugate margins. In particular, we analysed the structure of rifted margins by inspecting their geophysical signature from gravity and magnetic data. Observations of bathymetry profiles, where sediment thickness has been subtracted, and Bouguer gravity anomalies show an asymmetry in widths of the margin and the Continent Ocean Transition of these rifted conjugate margins. We then revisit the plate kinematics of regions where microcontinents formed in subduction-related set- tings with the aim to explain why microcontinents and continental fragments form in some areas and not in others. From our examples we find that microcontinents and continental fragments are associated with a component of rotation and/or oblique basin opening. The Central Mediterranean is characterised by a large 50◦ CCW rotation of the Corsica-Sardinia block due to Calabrian slab rollback which triggered rifting in the Liguro-Provençal Basin. In the South China Sea, rifting due to the southward subduction of the Proto-South China Sea propagated towards the SW resulting in a V-shaped basin. The evolution of the Coral Sea is thought to be controlled by the interplay between the northward motion of the Australian plate and the counterclockwise rotation of the Pacific plate. This triggered rifting and seafloor spreading NE of Australia resulting in the detachment of several microcontinents, including the Louisiade Plateau. Our preliminary analysis points towards the importance of small, enclosed basins as the locus of microcontinent formation in subduction settings and of rotational motions that allow separation of microcontinents from the parent continent.

• Straume, Eivind Olavson; Gaina, Carmen; Gjermundsen, Ada; Lacasce, Joseph Henry; Klocker, Andreas & Nikurashin, Maxim (2018). Global Miocene paleobathymetry: implications for paleo-ocean circulation. Fulltekst i vitenarkiv
• Faleide, Jan Inge; Abdelmalak, Mohamed Mansour; Shephard, Grace; Torsvik, Trond Helge; Gaina, Carmen & Tsikalas, Filippos [Vis alle 9 forfattere av denne artikkelen] (2017). Quantification and restoration of pre-drift extension across NE Atlantic conjugate margins. Fulltekst i vitenarkiv
• Stoker, Martyn S.; Stewart, M. A.; Shannon, P.M.; Bjerager, M.; Nielsen, Tove & Blischke, A [Vis alle 10 forfattere av denne artikkelen] (2017). An overview of the Upper Palaeozoic–Mesozoic stratigraphy of the NE Atlantic region. I Peron-Pinvidic, Gwenn; Hopper, John R.; Stoker, Martyn; Gaina, Carmen; Doornebal, Hans; Funck, Thomas & Árting, Uni (Red.), The NE Atlantic region: A reappraisal of crustal structure, tectono-stratigraphy and magmatic evolution. Geological Society of London. ISSN 9781786202789. s. 11–68. doi: 10.1144/SP447.2. Fulltekst i vitenarkiv Vis sammendrag

  This study describes the distribution and stratigraphic range of the Upper Palaeozoic–Mesozoic succession in the NE Atlantic region, and is correlated between conjugate margins and along the axis of the NE Atlantic rift system. The stratigraphic framework has yielded important new constraints on the timing and nature of sedimentary basin development in the NE Atlantic, with implications for rifting and the break-up of the Pangaean supercontinent. From a regional perspective, the Permian–Triassic succession records a northwards transition from an arid interior to a passively subsiding, mixed carbonate–siliciclastic shelf margin. A Late Permian–earliest Triassic rift pulse has regional expression in the stratigraphic record. A fragmentary paralic to shallow-marine Lower Jurassic succession reflects Early Jurassic thermal subsidence and mild extensional tectonism; this was interrupted by widespread Mid-Jurassic uplift and erosion, and followed by an intense phase of Late Jurassic rifting in some (but not all) parts of the NE Atlantic region. The Cretaceous succession is dominated by thick basinal-marine deposits, which accumulated within and along a broad zone of extension and subsidence between Rockall and NE Greenland. There is no evidence for a substantive and continuous rift system along the proto-NE Atlantic until the Late Cretaceous.

• Geissler, Wolfram; Gaina, Carmen; Hopper, John R.; Funck, Thomas; Blischke, A & Árting, Uni [Vis alle 9 forfattere av denne artikkelen] (2017). Seismic volcanostratigraphy of the NE Greenland continental margin. I Peron-Pinvidic, Gwenn; Hopper, John R.; Stoker, Martyn; Gaina, Carmen; Doornebal, Hans; Funck, Thomas & Árting, Uni (Red.), The NE Atlantic region: A reappraisal of crustal structure, tectono-stratigraphy and magmatic evolution. Geological Society of London. ISSN 9781786202789. s. 149–170. doi: 10.1144/SP447.11. Fulltekst i vitenarkiv Vis sammendrag

  The Early Eocene continental break-up between the NE Greenland and the mid-Norwegian–SW Barents Sea margins was associated with voluminous magmatism and led to the emplacement of massive volcanic complexes including wedges of seawards-dipping reflections (SDR). We study the distribution of these break-up-related volcanic rocks along the NE Greenland margin by revisiting existing seismic reflection data and comparing our observations to better-studied segments of the conjugate margin. Seismic facies types match between the conjugate margins and show strong lateral variations. Seaward-dipping wedges are mapped offshore East Greenland, the conjugate to the Vøring continental margin. The geophysical signature of the SDRs becomes less visible towards the north, as it does along the conjugate Lofoten–Vesterålen margin. We suggest that the Traill Ø volcanic ridge is a result of plume–ridge interactions formed between approximately 54 and 47 Ma. North of the East Greenland Ridge, strong basement reflections conjugate to the Vestbakken Volcanic Province are interpreted as lava flows or ‘spurious’ SDRs. We discuss our findings in conjunction with results from seismic wide-angle experiments, gravity and magnetic data. We focus on the spatial and temporal relationships of the break-up volcanic rocks, and their structural setting in a late rift and initial oceanic drift stage.

• Blischke, A; Gaina, Carmen; Hopper, John R.; Peron-Pinvidic, Gwenn; Brandsdottir, Bryndis & Guarnieri, Pierpaolo [Vis alle 8 forfattere av denne artikkelen] (2017). The Jan Mayen microcontinent: an update of its architecture, structural development and role during the transition from the Ægir Ridge to the mid-oceanic Kolbeinsey Ridge. I Peron-Pinvidic, Gwenn; Hopper, John R.; Stoker, Martyn; Gaina, Carmen; Doornebal, Hans; Funck, Thomas & Árting, Uni (Red.), The NE Atlantic region: A reappraisal of crustal structure, tectono-stratigraphy and magmatic evolution. Geological Society of London. ISSN 9781786202789. s. 299–337. doi: 10.1144/SP447.5. Fulltekst i vitenarkiv Vis sammendrag

  We present a revised tectonostratigraphy of the Jan Mayen microcontinent (JMMC) and its southern extent, with the focus on its relationship to the Greenland–Iceland–Faroe Ridge area and the Faroe–Iceland Fracture Zone. The microcontinent's Cenozoic evolution consists of six main phases corresponding to regional stratigraphic unconformities. Emplacement of Early Eocene plateau basalts at pre-break-up time (56–55 Ma), preceded the continental break-up (55 Ma) and the formation of seawards-dipping reflectors (SDRs) along the eastern and SE flanks of the JMMC. Simultaneously with SDR formation, orthogonal seafloor spreading initiated along the Ægir Ridge (Norway Basin) during the Early Eocene (C24n2r, 53.36 Ma to C22n, 49.3 Ma). Changes in plate motions at C21n (47.33 Ma) led to oblique seafloor spreading offset by transform faults and uplift along the microcontinent's southern flank. At C13n (33.2 Ma), spreading rates along the Ægir Ridge started to decrease, first south and then in the north. This was probably complemented by intra-continental extension within the JMMC, as indicated by the opening of the Jan Mayen Basin – a series of small pull-apart basins along the microcontinent's NW flank. JMMC was completely isolated when the mid-oceanic Kolbeinsey Ridge became fully established and the Ægir Ridge was abandoned between C7 and C6b (24–21.56 Ma).

• Gaina, Carmen; Nasuti, Aziz; Kimbell, G & Blischke, A (2017). Break-up and seafloor spreading domains in the NE Atlantic. I Peron-Pinvidic, Gwenn; Hopper, John R.; Stoker, Martyn; Gaina, Carmen; Doornebal, Hans; Funck, Thomas & Árting, Uni (Red.), The NE Atlantic region: A reappraisal of crustal structure, tectono-stratigraphy and magmatic evolution. Geological Society of London. ISSN 9781786202789. s. 393–417. doi: 10.1144/SP447.12. Fulltekst i vitenarkiv Vis sammendrag

  An updated magnetic anomaly grid of the NE Atlantic and an improved database of magnetic anomaly and fracture zone identifications allow the kinematic history of this region to be revisited. At break-up time, continental rupture occurred parallel to the Mesozoic rift axes in the south, but obliquely to the previous rifting trend in the north, probably due to the proximity of the Iceland plume at 57–54 Ma. The new oceanic lithosphere age grid is based on 30 isochrons (C) from C24n old (53.93 Ma) to C1n old (0.78 Ma), and documents ridge reorganizations in the SE Lofoten Basin, the Jan Mayen Fracture Zone region, in Iceland and offshore Faroe Islands. Updated continent–ocean boundaries, including the Jan Mayen microcontinent, and detailed kinematics of the Eocene–Present Greenland–Eurasia relative motions are included in this model. Variations in the subduction regime in the NE Pacific could have caused the sudden northwards motion of Greenland and subsequent Eurekan deformation. These events caused seafloor spreading changes in the neighbouring Labrador Sea and a decrease in spreading rates in the NE Atlantic. Boundaries between major oceanic crustal domains were formed when the European Plate changed its absolute motion direction, probably caused by successive adjustments along its southern boundary.

• Gaina, Carmen; Blischke, A; Geissler, Wolfram; Kimbell, G & Erlendsson, Ögmundur (2017). Seamounts and oceanic igneous features in the NE Atlantic: a link between plate motions and mantle dynamics. I Peron-Pinvidic, Gwenn; Hopper, John R.; Stoker, Martyn; Gaina, Carmen; Doornebal, Hans; Funck, Thomas & Árting, Uni (Red.), The NE Atlantic region: A reappraisal of crustal structure, tectono-stratigraphy and magmatic evolution. Geological Society of London. ISSN 9781786202789. s. 419–442. doi: 10.1144/SP447.6. Fulltekst i vitenarkiv Vis sammendrag

  A new regional compilation of seamount-like oceanic igneous features (SOIFs) in the NE Atlantic points to three distinct oceanic areas of abundant seamount clusters. Seamounts on oceanic crust dated 54–50 Ma are formed on smooth oceanic basement, which resulted from high spreading rates and magmatic productivity enhanced by higher than usual mantle plume activity. Late Eocene–Early Miocene SOIF clusters are located close to newly formed tectonic features on rough oceanic crust in the Irminger, Iceland and Norway basins, reflecting an unstable tectonic regime prone to local readjustments of mid-ocean ridge and fracture zone segments accompanied by extra igneous activity. A SOIF population observed on Mid-Miocene–Present rough oceanic basement in the Greenland and Lofoten basins, and on conjugate Kolbeinsey Ridge flanks, coincides with an increase in spreading rate and magmatic productivity. We suggest that both tectonic/ kinematic and magmatic triggers produced Mid-Miocene–Present SOIFs, but the Early Miocene westwards ridge relocation may have played a role in delaying SOIF formation south of the Jan Mayen Fracture Zone. We conclude that Iceland plume episodic activity combined with regional changes in relative plate motion led to local mid-ocean ridge readjustments, which enhanced the likelihood of seamount formation.

• Struijk, Maartje; Tesauro, Magdala; Lebedeva-Ivanova, Nina; Beekman, Fred; Gaina, Carmen & Cloetingh, Sierd (2016). Lithospheric thermal and strength model of the Arctic region. Fulltekst i vitenarkiv
• Medvedev, Sergei; Minakov, Alexander; Lebedeva-Ivanova, Nina & Gaina, Carmen (2016). Understanding lithospheric stresses in Arctic: constraints and models. Fulltekst i vitenarkiv
• Lebedeva-Ivanova, Nina; Gaina, Carmen; Minakov, Alexander & Kashubin, Sergey (2016). Comparison of publically available Moho depth and crustal thickness grids with newly derived grids by 3D gravity inversion for the High Arctic region. Fulltekst i vitenarkiv
• Lebedeva-Ivanova, Nina; Gaina, Carmen & Kashubin, Sergey (2016). Validation of the 3D Moho depth models by active seismic 2D models for the High Arctic. Fulltekst i vitenarkiv
• Gaina, Carmen; Lebedeva-Ivanova, Nina; Minakov, Alexander; Nikishin, Anatoly; Faleide, Jan Inge & Schweitzer, Johannes [Vis alle 11 forfattere av denne artikkelen] (2016). 4D Arctic: Structure and Evolution of Arctic Crust and Mantle Based on Multi-Scale Geophysical Studies – results from an international, multi-disciplinary project. Fulltekst i vitenarkiv
• Anzulovic, Ana; Caracas, Razvan & Gaina, Carmen (2025). Volatile control on kimberlite melt structure, density, and viscosity: Atomistic study with implications for kimberlite volcanism. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  The way a magma erupts is largely controlled by its volatile content, primarily carbon dioxide (CO₂) and water. This is particularly true for volatile-rich kimberlite magmas, which originate deep in the upper mantle beneath thick, cool continental lithosphere. Kimberlites are known for their rapid ascent and ability to transport mantle fragments to the surface; these characteristics make them the natural transport mechanism and primary host rocks of diamonds. As kimberlite magmas no longer erupt, our understanding of their volcanism relies on studying the altered rocks explosively emplaced in carrot-shaped volcanic pipes. To investigate the drivers of kimberlite volcanism, Ana Anzulović has developed an atomistic model of a kimberlite melt. The findings in the doctoral thesis work indicate that the deciding factor for a successful eruption is magma’s CO₂ content; at least 8.2 wt% is required for the melt to reach the surface. Simulting melt chemistry shows that carbon plays a dual role. At high pressure, it polymerizes the melt structure, but at lower pressure, it exsolves from the melt, driving vaporization. Both carbon and water lower the melt's density and viscosity, but water has a particularly strong depolymerizing effect, making the melt highly mobile.

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