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We present results from a sediment core collected from a pockmark field on the Vestnesa Ridge (~ 80° N) in the eastern Fram Strait. This is the only deep-water gateway to the Arctic, and one of the northernmost marine gas hydrate provinces in the world. Eight 14C AMS dates reveal a detailed chronology for the last 14 ka BP. The δ 13C record measured on the benthonic foraminiferal species Cassidulina neoteretis shows two distinct intervals with negative values termed carbon isotope excursion (CIE I and CIE II, respectively). The values were as low as −4.37‰ in CIE I, correlating with the Bølling–Allerød interstadials, and as low as −3.41‰ in CIE II, correlating with the early Holocene. In the Bølling–Allerød interstadials, the planktonic foraminifera also show negative values, probably indicating secondary methane-derived authigenic precipitation affecting the foraminiferal shells. After a cleaning procedure designed to remove authigenic carbonate coatings on benthonic foraminiferal tests from this event, the 13C values are still negative (as low as −2.75‰). The CIE I and CIE II occurred during periods of ocean warming, sea-level rise and increased concentrations of methane (CH4) in the atmosphere. CIEs with similar timing have been reported from other areas in the North Atlantic, suggesting a regional event. The trigger mechanisms for such regional events remain to be determined. We speculate that sea-level rise and seabed loading due to high sediment supply in combination with increased seismic activity as a result of rapid deglaciation may have triggered the escape of significant amounts of methane to the seafloor and the water column above.

Mulitbeam swath bathymetry and reflection seismic data image large submarine landslide complexes along ocean margins worldwide. However, slope failure initiation, acceleration of motion and mass-transport dynamics of submarine landslides, which are all key to assess their tsunamigenic potential or impact on offshore infrastructure, cannot be conclusively deduced from geometric expression and acoustic characteristics of geophysical data sets alone, but cores and in situ data from the subsurface are needed to complement our understanding of submarine landslide dynamics. Here we present data and results from drilling, logging and coring thick mass-transport deposits (MTDs) in the Nankai Trough accretionary prism during Integrated Ocean Drilling Program (IODP) Expeditions 333 and 338. We integrate analysis on 3D seismic and Logging While Drilling (LWD) data sets, with data from laboratory analysis on core samples (geotechnical shear experiments, X-ray Computed Tomography (X-CT), Scanning Electron Microscopy (SEM) of deformation indicators, and magnetic fabric analysis) to study nature and mode of deformation and dynamics of mass transport in this active tectonic setting. In particular, we show that Fe-S filaments commonly observed on X-ray CT data of marine sediments, likely resulting from early diagenesis of worm burrows, are folded in large MTDs and display preferential orientation at their base. The observed lineation has low dip and is interpreted as the consequence of shear along the basal surface, revealing a new proxy for strain in soft sediments that can be applied to cores that reach through the entire depth of MTDs. Shear deformation in the lower part of thick MTDs is also revealed from AMS data, which ¿ in combination with other paleo-magnetic data - is used to reconstruct strain and transport direction of the landslides

Benthic foraminiferal assemblages from sediments around active or recently active hydrothermal vents in the Aeolian Arc have been investigated in four areas with different hydrothermal mineralization and seafloor exhalative activity at depths between 60 and 300 m. Active hydrothermal spots were distinguished from the surrounding sediments by direct observations by a Remotely Operated Vehicle (ROV) and subsequent seafloor sampling. Samples were taken at different water depths and are characterized by a number of mineralogies reflecting the changing temperature of the hydrothermal fluids. Overall, benthic foraminifera are absent from sites with high-temperature hydrothermal emissions, and their distribution at sites of low-temperature emissions is very patchy, depending on the physical and/or chemical conditions reflecting differences in temperature and composition of the emitted fluids. In the Secca del Capo area, which is free from recent emission activity, the benthic foraminiferal population is indicative of a normal marine environment, with Globocassidulina subglobosa, Cassidulina crassa, and Gavelinopsis lobatulus. In the Basiluzzo, Secca dei Pesci, and Panarea areas, which are characterized by different degrees of hydrothermal activity, three distinct assemblages have been recognized. The first assemblage is dominated by Ammodiscus catinus, Glomospira charoides, and Glomospira gordialis and indicates hydrothermal influence. The second assemblage, with Lobatula lobatula, Asterigerinata mamilla, Rosalina globularis, and Quinqueloculina spp. as main constituents, indicates a seagrass environment influenced by diffuse emissions. The third assemblage with abundant A. catinus, Ammoglobigerina globigeriniformis, G. gordialis and Haplophragmoides canariensis suggests low pH conditions resulting from acidic hydrothermal emissions, leading to the dissolution of calcium carbonate tests.

Euthecosomata pteropods were analysed in core sediments collected in the framework of the 2016 EUROFLEETS2 SEMSEEP cruise, offshore of Israel, in the eastern Mediterranean Sea. The investigated cores were retrieved in a deep-sea coral area at 690 m depth, an actively methane-seeping pockmark area at 1038 m depth, and a deep-sea channel area at 1310 m water depth. We identified and documented the pteropod species belonging to the families Heliconoididae, Limacinidae, Creseidae, Cavoliniidae, Cliidae, and Hyalocylidae and to some heteropods. Our study highlights the importance of investigating pteropods in the size fractions > 63 μm instead of the > 125 μm only. In particular, neglecting the small size fraction may result in a remarkable (up to 50 %-60 %) underestimation of the relative abundance of the epipelagic species Creseis acicula and Creseis conica and the mesopelagic species Heliconoides inflatus. This may significantly affect palaeoenvironmental reconstructions. The observed presence of tropical species supports the suggestion that the eastern Mediterranean is a refugium for these species. This study provides a basic benchmark for the late Holocene evolution of pteropod and heteropod distribution over 5800-5300 cal BP across the base of the south-eastern Levantine margin., Journal of Micropalaeontology, 42 (1), ISSN:0262-821X

Pteropods are holoplanktonic molluscs presently endangered because their fragile aragonitic shell is very sensitive to ocean acidification. The preservation of pteropods, and in particular of the mesopelagic Heliconoides (Limacina) inflatus, has been used to assess aragonite saturation state in Quaternary sediments (Limacina Dissolution Index, LDX) as an inferred proxy for climatic changes. Three deep-sea cores retrieved in 2016 during the EUROFLEETS2 SEMSEEP cruise offshore Israel are investigated to assess the preservation degree of H. inflatus (d'Orbigny, 1835) in representative environments across the base of the southeastern Mediterranean margin (cold water coral, active seepage pockmark and deep sea channel areas). In some core intervals, yellowish, recrystallized internal molds of this species are present. They have been previously observed in the Eastern Mediterranean, but the nature and origin of their colour was never explained. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD) revealed that the recrystallized molds of the H. inflatus shells are formed by aragonite needles and high-Mg calcite crystals. The formation and preservation of these internal molds is induced by advective methane emissions, typically precipitating aragonite and High-Mg calcite phases close to the sediment–water interface. These molds were never used in previous applications of the LDX or in any existing ranking of pteropod preservation. Therefore, we have categorized these peculiar features combining previous pteropod ranking descriptions with the new observations to develop a modified biotic index (Heliconoides Modified Dissolution Index-HMDI). High values of the HMDI at the base of the pockmark core correspond to the interval where also active seepage-related features – e.g., bubble emissions, low-oxygen benthic foraminifera, chemosymbiotic molluscs, small fragments of authigenic carbonate crusts and slightly depleted δ13C values – occur, showing the applicability of the HMDI to methane seeps environments., Ecological Indicators, 152, ISSN:1470-160X, ISSN:1872-7034

The origin of modern seafloor methane emissions in the Barents Sea is tightly connected to the glacio-tectonic and oceanographic transformations following the last ice age. Those regional events induced geological structure re-activation and destabilization of gas hydrate reservoirs over large areas of the European continental margins, sustaining widespread fluid plumbing systems. Despite the increasing number of new active seep discoveries, their accurate geochronology and paleo-dynamic is still poorly resolved, thus hindering precise identification of triggering factors and mechanisms controlling past and future seafloor emissions. Here, we report the distribution, petrographic (thin section, electron backscatter diffraction), isotopic (δ13C, δ18O) and lipid biomarker composition of methane-derived carbonates collected from Leirdjupet Fault Complex, SW Barents Sea, at 300 m depth during an ROV survey in 2021. Carbonates are located inside a 120 x 220 m elongated pockmark and form 2 bodies protruding for about 2 m above the adjacent seafloor. Microstructural analyses of vein-filling cements showed the occurrence of three–five generations of isopachous aragonitic cement separated by dissolution surfaces indicative of intermittent oxidizing conditions. The integration of phase-specific isotopic analysis and U/Th dating showed δ13C values between −28.6‰ to −10.1‰ and δ18O between 4.6‰ and 5.3‰, enabling us to track carbonate mineral precipitation over the last ∼8 ka. Lipid biomarkers and their compound-specific δ13C analysis in the bulk carbonate revealed the presence of anaerobic methanotrophic archaea of the ANME-2 clade associated with sulfate-reducing bacteria of the Seep-SRB1 clade, as well as traces of petroleum. Our results indicate that methane and petroleum seepage in this area followed a similar evolution as in other southernmost Barents Sea sites controlled by the asynchronous deglaciation of the Barents Sea shelf, and that methane-derived carbonate precipitation is still an active process at many Arctic locations.

During the Miocene, hydrocarbon seep-carbonates located atop intrabasinal highs and associated with sediment instability, formed commonly at the deformation front of the Northern Apennine collisional orogen. The parallelism between the structural trend and the distribution of seep-carbonates suggests a close relationship between tectonics and gas/fluid emission. The “Montepetra intrabasinal high” was formed during the closure stage of the foredeep, being related to the synsedimentary growth of an anticline. Field geometry suggests that detachment folding was the leading mechanism of anticline growth and synsedimentary instability along the anticline flanks. Ten different bodies of seep-carbonates occur in the Tortonian–early Messinian sediments: nine in the hinge zone and one in the southern backlimb of the anticline. Foraminiferal study, geochemistry, facies investigation and the three-dimensional geometry of carbonate bodies with respect to the encasing terrigenous sediments indicate a protracted (late Tortonian–early Messinian) activity of fluid migration with re-mobilization and ascent of sediments from the core of the anticline, stabilization of chemosynthesis-related communities, and in-situ brecciation. Seepage atop the intrabasinal high was fed by different circuits: one related to the compaction-dewatering of shallow (Tortonian–early Messinian) sediments, and a deeper one related to the deformation of the anticline core and to the activity of detachment surfaces and of faults propagating through the sedimentary cover.

Benthic foraminifera from seep carbonates and from enclosing non-seep marls present within Miocene formations in the Northern Apennines (Italy) were investigated as proxies of methane seepage in the marine environment Negative delta(13)C values of benthic foraminifera from these seeps indicate unambiguously the local influence of CO(2) produced by microbial anaerobic methane oxidation on the benthic ecosystem. Calcareous species living within methane seeps display delta(13)C values ranging from -9.04 to -25.74 parts per thousand PDB, whereas in the coeval surrounding marls the same species display delta(13)C values from -1.54 to 0.62 parts per thousand PDB. Different species (Cibicidoides kullenbergi C. pachyderma, Siphonina rethiculata, Planulina wuellestorfi, Bolivina miocenica, Brizalina dilatata, Vulvulina pennatula, and Cibicides praecinctus) in different seep carbonates indicate that benthic foraminifera, independently of the taxa and of microhabitat preferences, have more negative delta(13)C values than those found in the enclosing marls. Therefore each species represents a potential proxy for past seafloor methane emissions. In addition to the calcareous species, the agglutinated species Vulvulina pennatula displays -27.5 parts per thousand PDB in seep carbonates against -2.69 parts per thousand PDB in the enclosing marls. This suggests that the species utilized strongly (13)C depleted carbonate particles from authigenic carbonate precipitation during the mineralization of their tests.

Immersive virtual reality can potentially open up interesting geological sites to students, academics and others who may not have had the opportunity to visit such sites previously. We study how users perceive the usefulness of an immersive virtual reality approach applied to Earth Sciences teaching and communication. During nine immersive virtual reality-based events held in 2018 and 2019 in various locations (Vienna in Austria, Milan and Catania in Italy, Santorini in Greece), a large number of visitors had the opportunity to navigate, in immersive mode, across geological landscapes reconstructed by cutting-edge, unmanned aerial system-based photogrammetry techniques. The reconstructed virtual geological environments are specifically chosen virtual geosites, from Santorini (Greece), the North Volcanic Zone (Iceland), and Mt. Etna (Italy). Following the user experiences, we collected 459 questionnaires, with a large spread in participant age and cultural background. We find that the majority of respondents would be willing to repeat the immersive virtual reality experience, and importantly, most of the students and Earth Science academics who took part in the navigation confirmed the usefulness of this approach for geo-education purposes.

Seafloor exploration using geo-referenced imagery from towed camera systems permits the investigation of small-scale (sub-cm) seabed features and a better understanding of submarine biogeochemical and physical processes, environments and their linkages. Decades of visual exploration of cold seeps have uncovered a variety of chemosynthetic communities often associated with gas bubbling and methane-derived authigenic carbonates, with the spatial distribution of these features reflecting the magnitude of methane flux through the sediment. In this study, the benefits of an integrated approach based on site-specific seafloor imaging and pore water analysis are demonstrated in quantifying total methane fluxes associated with different seep-habitats. This includes the investigation of a newly discovered cold seep in the SW Barents Sea, identified as the Leirdjupet Fault Complex (73.5° N, 21° E, 300–350 m water depth), using a total of 18 km of TowCam dives and four multicore sediment samples. The results document an extreme variability in methane flux linked to seafloor habitats with estimated total fluxes of 136.2 g CH4 yr−1 from an area characterized by microbial mats and tubeworms (85 m2) and 87.8 g CH4 yr−1 from a methane-derived authigenic carbonate area (50 m2). Further integrated studies, at both habitat- and regional-scales, are required for monitoring cold seep evolution at high-latitude continental margins. These include the investigation of sites where the contemporaneous ice-sheet retreat, coupled with ocean warming, could lead to enhanced seafloor methane emissions from deep hydrocarbon and gas hydrate reservoirs.

The recurrence of mass-flow units within sapropel S1, an organic carbon-rich lower Holocene marker bed in the Eastern Mediterranean Sea, was used to study the interplay between earthquakes and sedimentation along the seismically active Calabrian Arc (Ionian Sea). Nine turbidite beds interrupt anoxic conditions during the deposition of sapropel S1. Each of these turbidites is associated with sharp grain size and geochemical elemental anomalies (high Al and Si, low Ca and coarse-grained basal part marked by Zr peaks), and with displaced foraminiferal species from different bathymetric ranges. We used these proxies to identify turbidite beds also above and below the sapropel, where turbidite signature is less clear due to the absence of major color changes. Turbidite structure and composition, as well as comparison with historical seismoturbidites, suggest a seismic triggering for such mass flow events. The peculiar color, well-known composition, geochemistry and age of sapropel S1, make this unit a key bed within which turbidites may be considered a sort of sedimentary “bar code” recording high-energy events within the background pelagic sedimentation; deciphering this code will reconstruct paleo-seismicity in this well-defined stratigraphic interval. The pelagic units bracketing turbidite beds were radiometrically dated, and the age of the sapropel S1, deduced through age modeling, is between 6.0 and 10.2 kyr cal BP. The emplacement age of each turbidite was estimated considering the average time-interval between successive turbidite beds (from pelagic sediment thickness and sedimentation rate). Subsequently these ages were further refined through age modeling. In this way, we compiled a catalogue of mass flow events during sapropel S1 deposition, a time span long enough to include several earthquake cycles and allow reliable seismic and tsunami hazard assessment in this area.

La Grotta delle Spade è stata scoperta all’interno della Miniera di Naica nel 1910 ed è diventata immediatamente una delle più famose grotte di miniera del mondo per i gradi cristalli di gesso di origine idrotermale (fino ad oltre 2 m di lunghezza), che la rivestivano completamente. Nonostante la sua fama, comunque, nessuno studio specifico era stato effettuato sino ad oggi al suo interno. Lo studio ha permesso di evidenziare la presenza di associazioni di ossidi-idrossidi idrati di ferro, manganese, piombo e zinco, spesso in forma amorfa o criptocristallina, e, a volte, chiaramente depositatisi su biomasse. La loro presenza è da correlare all’ossidazione della parte più superficiale dei giacimenti minerari che è stata particolarmente intensa durante uno degli stadi evolutivi della grotta. Con minore frequenza sono stati osservati anche altri minerali, quali celestina, dolomite ed hectorite, la presenza dei quali permette di meglio definire la storia evolutiva di questa cavità, che è risultata essere molto più complessa rispetto a quella delle analoghe grotte scoperte solo recentemente al livello -290 m della stessa miniera

Benthic foraminiferal assemblages from sediments around active or recently active hydrothermal vents in the Aeolian Arc have been investigated in four areas with different hydrothermal mineralization and seafloor exhalative activity at depths between ~60 and ~300 m. Active hydrothermal spots were distinguished from the surrounding sediments by direct observations by a Remotely Operated Vehicle (ROV) and subsequent seafloor sampling. Samples were taken at different water depths and are characterized by a number of mineralogies reflecting the changing temperature of the hydrothermal fluids. Overall, benthic foraminifera are absent from sites with high-temperature hydrothermal emissions, and their distribution at sites of low-temperature emissions is very patchy, depending on the physical and/or chemical conditions reflecting differences in temperature and composition of the emitted fluids. In the Secca del Capo area, which is free from recent emission activity, the benthic foraminiferal population is indicative of a normal marine environment, with Globocassidulina subglobosa, Cassidulina crassa, and Gavelinopsis lobatulus. In the Basiluzzo, Secca dei Pesci, and Panarea areas, which are characterized by different degrees of hydrothermal activity, three distinct assemblages have been recognized. The first assemblage is dominated by Ammodiscus catinus, Glomospira charoides, and Glomospira gordialis and indicates hydrothermal influence. The second assemblage, with Lobatula lobatula, Asterigerinata mamilla, Rosalina globularis, and Quinqueloculina spp. as main constituents, indicates a seagrass environment influenced by diffuse emissions. The third assemblage with abundant A. catinus, Ammoglobigerina globigeriniformis, G. gordialis and Haplophragmoides canariensis suggests low pH conditions resulting from acidic hydrothermal emissions, leading to the dissolution of calcium carbonate tests. D 2005 Elsevier B.V. All rights reserved.