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This expedition ran between July 28 and August 3 2020, targeting three sites in the Barents Sea, an area of glacial landforms in Ingøydjupet trough, the Håkon Mosby Mud Volcano and the Sorvestnaget Sand Wave area. Our short but productive expedition gave three post-doctoral researchers the opportunity to follow a research hypothesis from conception through planning and data collection aboard the research vessel, as well as plan and lead a research expedition. At the Ingøydjupet and Håkon Mosby Mud Volcano study areas, our objectives were to collect cores for geochemical analyses of the area and bathymetry data for geophysical analyses while the objectives at the sand waves are were to collect a time-lapse multibeam survey and grab samples for sedimentological analysis The cruise may be known as: CAGE20_3

Lake Baikal (LB) is the only freshwater ancient lake on Earth where animals inhabit all bathymetric zones down to the deepest sites (approximately 1640 m). However, there is very little data on the composition of their abyssal harpacticoid fauna. On the basis of the samples collected in LB in 2010–2017 at a depth of 270–1632 m, analysis of the fauna composition and species diversity of harpacticoids in the deep-water zone is presented. Studies were conducted in all parts of the lake, including areas of a hydrothermal, oil–methane seeps, and mud volcanoes. Nineteen Baikal endemic morphological species of the genera Bryocamptus, Attheyella, and Moraria (Baikalomoraria) were found. A brief description of the taxa morphology is presented. The genus Bryocamptus was the richest by species number at the studied sites, and Bryocamptus smirnovi Borutzky was the most frequent. The most diverse (8 species) was the fauna of the Saint Petersburg methane seep. Studies have shown that the taxonomic diversity of harpacticoid copepods in the deep-water zone of LB is lower than in its littoral zone. According to two non-parametric species estimators (Chao 2 and Jackknife 1), a 1.5-fold increase of species richness of harpacticoids of the LB abyssal is expected.

International audience; Numerous studies of the offshore Niger Delta have documented substrate-related collapse systems based on widely spaced 2D seismic data that generally lack detailed age calibration, but shale evolution through time remains poorly understood. This is investigated in this study through a detailed interpretation of an industry 3D seismic survey and calibration with biostratigraphic data. Our results show an overall thinning of stratigraphy towards mobile shale in the northeast of the study area at least since the Burdigalian. This suggests the onset of shale deformation in the Burdigalian, contrary to suggestions that it initiated in the Tortonian or later. Increase in sedimentation rates over the late Eocene-Serravallian is interpreted to have contributed to early generation of overpressure and progradation of the offshore western Niger Delta siliciclastic wedge. This is inferred to have contributed to shale deformation and release of overpressured fluids and solid particles through mud volcanoes and sea floor pockmarks. While mud volcanoes and giant pockmarks provide clue on deeper fluid migration, smaller pockmarks above normal faults, buried submarine channels and MTDs, suggest shallower fluid migration. The presence of buckle folds support previous observations that the active compressional zone of the Niger Delta was in the present-day continental slope during the late Eocene before migrating to the outer fold-thrust-belt in the Pliocene. This study provides new insight into the long-term control (18 million years) of mobile shales on the stratigraphic evolution of the offshore western Niger Delta.

Introduction: The behavior and the rheology of mud during the emplacement of terrestrial sedimentary volcanism has been previously investigated (e.g., [1,2]). In contrast, this is not the case for Mars nor for other planetary bodies within the Solar System for which sedimentary volcanism has been proposed [e.g., 3]. The propagation behavior of low viscosity mud in a low-pressure chamber that partly simulated the surface environment of Mars was experimentally studied for the first time by [4,5]. Their work revealed that low viscosity mud flows could propagate over cold (273 K) surfaces at martian atmospheric pressure, however, the mechanism of such propagation is different to that observed on Earth. On Mars, mud propagating over cold surfaces should rapidly freeze due to evaporative cooling [6] forming an icy-crust leading to propagation in a similar manner to pahoehoe lava flows on Earth [4]. In contrast, mud propagating over a warm surface boils and levitates above the surface. The viscosity of ascending mud varies depending on its water content, and the behavior of high viscosity mud under martian atmospheric pressure remains unexplored. Experimental setup: We used the Mars Simulation Chamber at the Open University (UK) into which we inserted a 0.9 × 0.4 m plastic box filled with a ~10 cm thick layer of natural sand (ø ~200 µm) mixed with water to limit the infiltration of mud into the sand and to better maintain the temperature below 0°C. Inside was placed a container to accommodate 600 ml of mud (Fig. 1). The infilled box was cooled to a temperature of ~-20°C. The temperature of the mud when inserted into the container was 1-3°C and 20-22°C respectively. Two different viscosities were tested – the first mix contained 50 wt% clay (a bentonite composed of 76% montmorillonite, 23% illite and 1% kaolinite) and water (1:1 mix). The other was prepared by mixing 75 wt% clay with 25 wt% water (3:1). The pressure was gradually reduced from 1 bar to 6 mbar within a timeframe of minutes (rapid) or in >hour (slow). Each experimental run was triplicated to confirm reproducibility. Observations: With the 1:1 mixture, once the atmospheric pressure was reduced, the mud started to boil (Figure 2). In the case of mud at room temperature and a rapid pressure drop, significant boiling caused an ejection of muddy droplets from the container into the surroundings. Such behavior was not observed for other experiments and mud was extruded due to the volumetric increase. Once the pressure dropped below 7 mbar, freezing occurred leading to the formation of an icy-muddy crust. Once this crust covered the entire mud surface, additional boiling and volumetric increase was limited. However, when the crust broke up, gasses were capable to escape and the deflation was observed. For the 3:1 mixture vigorous boiling was not observed during the pressure drop. Instead, as the pressure decreased, the mud volume increased and sets of cracks developed on the surface. Regardless of the tested parameters, the volumetric increase was observed during all experiments as bubbles within the mud developed and increased their volume. In the case of 1:1 and 3:1 mixture the mud inflation reached up to ~15% and ~28% respectively (the observed volumetric changes were quantified by semi-manual processing of selected images using the PIV [Particle Image Velocimetry] and photogrammetry methods). In addition, we also observed a partial collapse of the newly formed foamy edifice as the gas trapped inside the mud escaped. This inflation and deflation of the mud often repeated and the magnitude of volumetric change leads to different morphologies (Figure 3). Discussion and conclusion: The volumetric increase is caused by the formation of small water vapor bubbles which are trapped within the mud (Figure 4). The buoyancy of the bubbles is not sufficient to overcome the drag force within the viscous material and rise to the surface. Hence, these bubbles remain trapped and gradually grow up to centimeter scale sizes. During their growth they push the mud out of the container resulting in horizontal and vertical inflation of the mud surface over cm- scales (e.g., see outlines in Figure 2). This behavior is not observed at terrestrial mud flows. Our experimental approach hence shows that viscous mud exposed to reduced atmospheric pressure behaves differently when compared to conditions on Earth. Acknowledgments: The access to the Large Mars Chamber at the Open University was provided by Europlanet 2024 RI which has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 871149. References: [1] O’Brien and Julien (1988), Journal of Hydraulic Engineering 114 [2] Laigle and Coussot (1997), J. Hydraul. Eng., 123 [3] Ruesch et al. (2019) Nature Geoscience 12 [4] Brož et al. (2020), Nature Geoscience [5] Brož et al. (2020), EPSL 545 [6] Bargery et al. (2010), Icarus 210(1). Fig. 1: Experimental setup. Figure 2: A sequence of images capturing the volumetric change of 1:1 mud (T=1°C) depending on the pressure value. The simplified sketch shows the extent of such changes indicated with different colors. Figure 3: Examples of morphologies resulting from inflation of the mud induced by low pressure conditions. The blue and red boxes mark different temperatures of the mud. Morphologies of 3:1 mud are relatively uniform, in contrast a wider variety exists for less viscous 1:1 mud. The white dashed lines mark the position of the 9 cm large container. Figure 4: Simplified concept of mud inflation due to the pressure drop. Behaviour of 1:3 mud based on work of [4].

Mud volcanoes are mud emissions generated by the rising gas from deep hydrocarbon deposits. The extruded material is mainly composed of methane, fossil salt water and clays, and results deposited on the ground forming cones and pools. The Salse di Nirano reserve is one of the oldest and ancient example of geological protected area, in Italy and in Europe. In this technical report it is widely described the terrestrial laser scanning (TLS) measurement campaign performed on February 2020 together with results and considerations/opportunities for planning an exhaustive monitoring of the area. The research aims at providing a reliable contribute in searching for possible correlations between areas movements and mud extrusions. In summary, this paper shows the first TLS observation carried out to start the monitoring of the studied phenomena., I vulcani di fango sono emissioni di fango generate dalla risalita di gas dai depositi profondi di idrocarburi. Il materiale che fuoriesce è costituito prevalentemente da metano, acqua salata fossile e argille, che si depositano intorno all’apertura generando le tipiche formazioni a cono e polla. Le Salse di Nirano costituiscono l’esempio più antico di vulcani di fango tutelati in Italia e tra i meglio conservati d’Europa. In questo rapporto tecnico si descrive il rilievo con laser scanning terrestre (TLS) realizzato nel febbraio 2020 per ottenere un modello di riferimento ad alta precisione, mostrando le fasi di studio e preparazione della campagna di misura e mettendo in evidenza limiti e opportunità di tale approccio. Lo scopo è quello di contribuire allo studio ed alla comprensione di eventuali correlazioni tra i movimenti superficiali del terreno ed eventi di estrusione dei fanghi. In sostanza, è la prima fase di misura per il monitoraggio dell’area e per la ricerca di pattern di deformazione relativi ai fenomeni presenti.

International audience; Different regimes are usually observed for fluid migration through an immersed granular layer. In this work, we report a puzzling behavior when injecting water at a constant flow rate through a nozzle at the bottom of an immersed granular layer in a Hele-Shaw cell. In a given range of parameters (granular layer height and fluid flow-rate) the granular bed is not only fuidized, but the particle-laden jet also exhibits periodic oscillations. The frequency and amplitude of the oscillations are quantified. The Strouhal number displays a power-law behavior as a function of a non-dimensional parameter, J, defined as the ratio between the jet velocity at the initial granular bed height and the inertial particle velocity. Fluid-particle coupling is responsible for the jet oscillations. This mechanism could be at the origin of the cyclic behavior of pockmarks and mud volcanoes in sedimentary basins.

Here we present the results of our mapping of a large field of landforms characterized by flow-like morphology in the southwestern part of Utopia Planitia. They have been previously interpreted as mud flows associated with a partly frozen muddy ocean [1,2]. We find that these features can be grouped into four separate classes with distinct shapes and sizes and a clear evolutionary sequence among them. This suggests that all 205 studied features spread across the 500 × 1300 km large area were formed by the same basic process and that the material likely originated from the same source. Introduction The deepest parts of Utopia Planitia served as depocenters or sinks since early in the Martian history [2,3] and would be the final destination for any material released during Hesperian catastrophic floods [4]. Consequently, it was proposed that a large body of water might once or repetitively have been present there [1,5]. However, such hypothesis is still controversial due to the lack of unambiguous morphological evidence [6]. A promising area to search for such evidence is Adamas Labyrinthus, where the presence of putative mud flows has been previously reported [2,5]. Data and Methods Our mapping is based on the global CTX Mosaic (5m/pixel) [7] which served as the base map for delineation of the observed features. The features were marked as point, linear, and polygonal features in a QGIS environment. HiRISE (0.3 m/pixel) and CTX stereo pairs were processed using the MarsSI service [8] to produce digital elevation models (DEM) for some studied landforms. This enabled us to calculate their basic morphometric characteristics, height and volume, but also to reveal the relative stratigraphy among them and their surroundings. Results We found and mapped 205 features with positive topography characterized by flow-like appearance (Fig. 1). We classified them into four groups based on their extent, shape, and morphological properties (e.g., surface roughness). The resulting classes are ‘hills’ (Fig. 2a), ‘ridges’ (Fig. 2b), ‘plateaus’ (Fig. 2c), and ‘complexly layered units’ (CLUs, Fig. 2d), but we note that landforms commonly show transitional stages, hence share characteristics of multiple classes (such as in Fig. 2b). Hills are the smallest studied features. They are characterized by circular plan-map appearance. Their surface texture can be either smooth or rough with flow-like structures extending beyond their bases (Fig. 2a). Hills can be solitary features or be associated with fractures, in which case they form hill chains. Ridges are elongated features with rough surface. They vary in width from narrow sub-kilometer stretches to wide and elevated smooth plateau-like features (see Fig. 2b) surrounded by hummocky rims. Plateaus (referred to in [2] as “etched flows”) are kilometer-sized features characterized by a smooth central uplifted unit usually surrounded by a rough boundary (Fig. 2c). The smooth unit often contains rimless pits. Plateaus sometimes superpose the polygonal throughs typical for Adamas Labyrinthus. The final type are CLUs represented by extensive and often chaotic combination of overlapping landforms mentioned above (Fig. 2d). Their relative stratigraphy is decipherable only with the use of DEMs. Discussion Previously, many flow-like features have been described elsewhere on Mars as lava flows [9,10]. At the first glance this might seem like a plausible scenario even here as the studied features bear many morphological similarities with terrestrial and martian lava flows. However, our survey did not reveal signs of subsidence or explosive excavation associated with studied features, which are commonly accompanying volcanic eruptions [e.g. 9,10]. We also did not find evidence of lava-water interactions (e.g., rootless cones) which would have favorable conditions to occur at this location as the studied features are superposed on terrain enriched in volatiles as documented by polygonal troughs, ghost craters and pedestal craters [2]. Instead, the morphological characteristics of the mapped features, transitions between their categories and the spatial context of the study suggest that the landforms are of sedimentary (mud) volcanic origin. Recently, Brož et al. [11] showed experimentally that low viscosity mud effusively emplaced onto the cold martian surface under the low atmospheric pressure of 7 mbar would behave similar to pahoehoe lava, and resulting landforms might have similar appearance. This is because the evaporative cooling of water would cause the formation of an icy crust on the surface of the mud flow, analogous to a solidified lava crust. This process might explain the observed shapes of the studied features. Conclusions We propose that the studied features were formed due to the expulsion of mud from a gradually freezing muddy body. Because of the climatic conditions on Mars such body would be freezing from the top down, causing an increase in the internal pressure of the still liquid mixture underneath. This would trigger the ascent of the mud towards the surface via cracks in the frozen crust and subsequent effusive eruptions. Once the mud would be exposed to the surface, it would spread by flowing over the surface, while freezing at the same time. This would limit its ability to flow but cause the resulting outflow to have an appearance similar to terrestrial lava flows. This process gave rise to the observed hills, ridges, plateaus and complexly layered units. Emergent landforms degraded over time as the volatile part of the compound sublimed away eventually leading to the characteristic morphology we observe today. Acknowledgements: VC, PB & YM were supported by Czech Science Foundation (#20-27624Y). References: [1] Jöns (1985), Lunar Planet. Sci. 16, 414–415; [2] Ivanov et al. (2014), Icarus 228, 121-140; [3] Frey et al. (2002), Geophysical Research Letters 29, no. 10, 22-1-22-4; [4] Carr (1996), Planetary and Space Science 44, 1411-1423; [5] Ivanov et al. (2015), Icarus 248, 383-391; [6] Sholes et al. (2021), Journal of Geophysical Research: Planets 126, no. 5; [7] Dickson et al. (2018), 49th Lunar and Planetary Science Conference 2018, LPI Contrib. No. 2083 ; [8] Quantin-Nataf et al. (2018), Planetary and Space Science 150, 157-170; [9] Hodges & Moore (1994), Atlas of volcanic features on Mars; [10] Hauber et al. (2009), JVGR 185, 69-95; [11] Brož et al. (2020), Nat. Geo. 13, 403-407

Mud volcanoes are rapidly-evolving geological phenomena characterized by the surface expulsion of sediments and fluids from over-pressurized underlying reservoirs. We investigate the Nirano Mud Volcano, Northern Italy, with seismic methods to better understand the dynamic evolution of the system and shed light on its subsurface structure. Our study allowed to detect and characterize three different types of high-frequency drumbeat signals that are present in the most active part of the mud volcano plumbing system. With a back-projection method based on the cross-correlation envelope of signals recorded at different station pairs, we can determine the source location of the drumbeats. These coincide with the location of V/H (vertical-to-horizontal) amplitude peaks obtained from an ambient vibration profile and resistivity anomalies identified in a previous study. We observe that the drumbeats are P-wave dominated signals, with characteristics similar to those found in magmatic settings, i.e. LPs (long-period signals). We suggest that such tremors originate from the migration of mud and gas inside the mud volcanic conduits. The source location, waveform and frequency content of the drumbeats evolve over time. We found that drumbeat occurrence is directly linked with morphological changes at surface.

Kilometre-sized flows (KSFs) have been observed in many regions on Mars and have been typically interpreted as lava flows. However, sedimentary volcanism has been proposed as an alternative origin for some KSFs. Remarkable examples of such hypothesized sedimentary KSFs are located at the southern margin of Chryse Planitia. There, the flows are associated with conical and dome-shaped edifices; however their formation mechanism remains enigmatic due to the absence of ground truth. Previous studies revealed that these KSFs consist of three morphological elements: a central depression, leveed central channels, and a distal portion of the fading channel(s). Here, we present new morphological results obtained on these KSFs using seven newly available Digital Elevation Models computed from HiRISE stereo pairs. Our investigation confirms that these features are aggradational and formed by the transport of a liquid. This material emerged from identified depressions and the presence of subtle mounds inside them is interpreted to mark the position of feeder vents. We also observe that the margins surrounding the central large channels are not continuous. They are cut by meter-sized troughs linking the central channels to units which have distinctive albedo and roughness compared to their surroundings. These bright units do not have a clear topographical expression, suggesting that the effused material originally flowing away from the central channel was easily removed after its emplacement. Such surface features are unlikely to be related to igneous deposits, since once lava is released from a main channel, it would rapidly solidify due to the heat loss and hence result in topographically distinct features. In contrast, such morphological expressions are more likely related to sedimentary volcanism and the emplacement of low viscosity water-rich mud. Sublimation, evaporation, infiltration or a combination of these processes should lead to water loss from the flows without leaving a detectable topographic expression but changing the roughness and hence albedo of the surface. The southern part of Chryse Planitia is a region on Mars where subsurface sediment mobilization could have operated in the past and hence represents a promising site for future exploration where deeper-sourced sedimentary deposits are exposed at the surface.

The article describes four populations (Pop) of the rare species (Tulipa biflora Pall., Ophrys apifera Huds., Rosa azerbajdzhanica Novopokr. & Rzazade, Pyrus salicifolia Pall.) found on mud volcanoes in the Greater Caucasus. Studying the flora of two volcanoes it has established that in the local flora of the Gyzmeidan mud volcano, were recorded 46 species belonging to 45 genera and 21 families, and in the Toragay mud volcano 23 species belonging 22 genera and 12 families. The types, density, ontogenetic condition state and demographic structure of populations have been determined. According to the spatial and demographic indicators of rare species populations has been determined that the highest average density and number of individuals of all ontogenetic states were noted in Pop 1 and the lowest in Pop 2. According to the indices Δ and ω, only Pop 4 is transitional, and the remaining populations are assigned as young type., В статье описаны четыре популяции (Pop) редких видов (Tulipa biflora Pall., Ophrys apifera Huds., Rosa azerbajdzhanica Novopokr. & Rzazade, Pyrus salicifolia Pall.), обнаруженных на грязевых вулканах Большого Кавказа. При изучении флоры двух вулканов установлено, что в мест-ной флоре грязевого вулкана Гызмейдан зарегистрировано 46 видов, принадлежащих к 45 родам и 21 семейству, а в грязевом вулкане Торагай – 23 вида, принадлежащих к 22 родам и 12 семействам. Изучены типы, плотность, онтогенетическое состояние и демографическая структура популяций. По пространственно-демографическим показателям популяций изученных видов установлено, что наибольшая средняя плотность и число особей всех онтогенетических состояний отмечена в Pop 1, а наименьшая – в Pop 2. По показателям Δ и ω только Pop 4 является переходной, а остальные являются молодыми.

Gas hydrate is found in cold, high-pressure, marine sediments around the world. Hydrate is important as a carbon sink, a natural geohazard, and a valuable economic resource. I use classic sedimentologic analyses, well log analysis, X-ray CT, seismic stratigraphy, pore pressure estimation, and basin modeling to elucidate the geologic conditions within highly-saturated, natural gas hydrate reservoirs in the deepwater northern Gulf of Mexico. I begin with the characterization of the channel-levee hydrate reservoir in GC-955 with grain size experiments, lithofacies mapping. Hydrate is found in thin-bedded layers of sandy silt that increase in net-to-gross and mean grainsize downhole. I use these results to interpret deposition of overbank sediment gravity flows from a deepwater bypass channel as it becomes increasingly confined by the levees it builds. Next, I use 3D seismic data to identify the relationship between similar channel-levee systems and venting seafloor gas mounds in the Terrebonne Basin of the Walker Ridge protraction area. I estimate the pore pressures, and show that below the hydrate phase boundary, free gas in the levees builds to a critical pressure and creates hydraulic fractures to the seafloor. I describe a conceptual model by which the venting process perturbs the hydrate stability zone, leading to further venting from shallower positions and the formation of distinct rows of gas mounds on the seafloor. Finally, I combine geomechanical properties of the GC-955 reservoir with the structure of the Terrebonne Basin system to show that the pressure estimates are well within reason. Together, these studies provide new insights into where hydrate is found, and how hydrate systems can both control and in turn be controlled by fluid flow, pressure, and stress in the deepwater environment

In the municipality of Canalete - Córdoba, in the village of La Lorenza, there is an important sedimentary volcanic system made up of volcanoes such as Palmar and San Diego, the western sector of the San Diego volcano being considered as the study area in the present investigation, the main objective of the study was to characterize the geomorphological features of the sector in order to provide information that favors the identification of threats due to sedimentary volcanism, this objective was achieved through the interpretation and analysis of UAV photographs by means of GIS in conjunction with field control. ; This project was worked on at a scale of 1: 500, managing to detail as many geoforms as possible in the studied area, within which taps, sauces, pools and multicrater leaks were found that could be correlated with different types of threat, thus allowing to determine that the San Diego mud volcano area studied is associated with mud gap and flow ejection threats and fires. RESUMEN ABSTRACT INTRODUCCIÓN OBJETIVOS REVISIÓN BIBLIOGRÁFICA MARCO CONCEPTUAL Volcanismo sedimentario Sensores remotos y teledetección Aplicación de imágenes VANT en la cartografía Caracterización geomorfológica ANTECEDENTES MATERIALES Y METODOS RESULTADOS Y DISCUSION CONCLUSIONES RECOMENDACIONES BIBLIOGRAFIA En el municipio de Canalete - Córdoba, en el corregimiento La Lorenza, se aprecia un importante sistema volcánico sedimentario constituido por volcanes como el Palmar y San Diego, siendo el sector occidental del volcán San Diego considerado como área de estudio en la presente investigación, el objetivo principal del estudio fue caracterizar los rasgos geomorfológicos del sector con el fin de aportar información que favorezca en la identificación de amenazas por volcanismo sedimentario, dicho objetivo fue alcanzado mediante la interpretación y análisis de fotografías VANT por medio de SIG en conjunto con control de campo; este proyecto se trabajó a escala de 1:500 logrando detallar la mayor cantidad de geoformas posibles en la zona estudiada, dentro de las cuales se encontraron grifos, salsas, piscinas y filtraciones multicrater que pudieron ser correlacionadas con distintos tipos de amenaza permitiendo así determinar que la zona estudiada del volcán de lodo San Diego está relacionado con amenazas por expulsión de flujo y brecha de lodo e incendios. Pregrado Ingeniero(a) Ambiental Trabajos de Investigación y/o Extensión

The article shows that the immersion of clay strata in the region of high temperatures and pressures creates two fluid dynamic zones. In the upper zone, clay porosity decreases, and sedimentation and diagenetic waters are released; these elision phenomena create abnormal reservoir pressure in reservoir layers and give rise to a complex system of fluid dynamics. It involves water and oil hydrocarbons penetrating. In the upper zone, hydrolysis of carbonates and cementation of sand formations take place. In the lower zone, compacted clays are developed, forming a closed physicochemical system. Background changes in water and organic matter give rise to ultrahigh fluid pressures. Crystallization waters, sybotaxic water vapor and gaseous hydrocarbons that arose at high temperatures are concentrated in different parts of the strata, and slowly migrate along cleavage cracks in the direction of areas with low pressure. The roots of vertical tectonic faults and non-cemented types are especially attractive for ultrahigh pressures. The formation of classical dikes, «horizons with inclusions» and mud volcanoes, as well as seismic phenomena accompanying eruptions of mud volcanoes, are associated with these sites.

Based on an analytical review of factual materials, the article discusses the peculiarities of the distribution of gas hydrates in the development zones of mud volcanism of the Mediterranean, Black and Caspian seas, which are direct indications of sedimentary gas complex. A comparative analysis of the composition of hydrate-forming fluids, sources and depths of gas hydrates distribution was performed. The article provides information on gas seeps and pokmarks. The presence of gas seepsand pokmarks in the water column and at the bottom of the Southern Caspian is assumed.

Three leptostracan species (Crustacea: Phyllocarida) are reported from mud volcanoes at the Moroccan margin of the Gulf of Cadiz (NE Atlantic). Nebalia strausi Risso, 1826 and N. abyssicola Fage, 1929 were found in experimentally deployed organic substrates in Mercator, Meknès and Darwin mud volcanoes; N. abyssicola was also found among bathymodiolin bivalves and is recorded for the first time in the Atlantic Ocean. The third species was collected from the Gemini mud volcanoes and is described herein as Sarsinebalia ledoyeri sp. nov. The new species is characterised by having the eyes provided with ommatidia and lacking pigment, the ventral margin of the eye is concave along distal half, the antennular scale is more than twice as long as wide, the second article of the mandibular palp bears one seta on lateral surface about 0.5 times as long as the article and one subterminal seta longer than the third article, the distal article of the maxilla II endopod is about 1.8 times as long as the proximal article, the maxilla II exopod is clearly longer than the endopod proximal article, the lateral margin of the pleopod I exopod lacks setae and the posterodorsal border of pleonites VI–VII is provided with rounded to pointed denticles.

Eight species of Ophryotrocha and one of Parougia were identified from organic substrata (wood and alfalfa) sampled at the Gulf of Cadiz and Western Iberian Margin (NE Atlantic). Morphological examination and molecular phylogenetic analyses, based on the nuclear gene H3 and the mitochondrial gene 16S, indicate the presence of four species new to science: Ophryotrocha chemecoli sp. nov., O. nunezi sp. nov., O. geoffreadi sp. nov. and Parougia ougi sp. nov. The geographic and/or bathymetric distribution is extended for four previously known species: O. cantabrica, O. hartmanni, O. mammillata and O. scutellus. Another species may also have its distribution extended, pending the molecular confirmation of its identity: O. lipscombae. Full descriptions and figures are given for all the new species and, when justified, also for the previously known ones. The original description of O. scutellus is amended. New DNA sequences are given for eight of the nine species studied here. The ecology and geographic distribution of the reported species is discussed.

Earthquakes can influence the activity of mud volcanoes and other fluid expulsion systems, which may erupt or change their activity shortly after the seismic event. This study investigates the influence of static and dynamic stresses, produced by some important earthquakes in Taiwan, on fluid expulsion systems that have coseismically responded to such events. Peak dynamic stresses have been estimated at the considered seepage features using available peak ground velocities, while computation of static stress changes has been performed considering the orientation of the feeder systems that are structurally controlling mud volcano development. Feeder dike orientations have been determined on the basis of the geometric characteristics of mud volcanoes (e.g., volcano elongation, vent alignments), and their spatial distribution shows some correlation with regional structures and the active tectonic stress field. The responses of Taiwanese fluid expulsion systems to earthquakes are correlated with the amplitude of dynamic stresses generated by seismic waves, while static stresses have or have not contributed to the triggering depending on the case. This observation suggests that static stresses are unlikely to be a necessary causative mechanism, as seepage systems do respond to earthquakes even when changes in static stress are unfavourable.

Mud volcanoes serve as direct indicators of deep deposits of oil and gas, and often accumulations of iron, mercury, arsenic and other elements. Mud volcanoes in Azerbaijan are occured in groups or detached in the area of Southeast immersion of the Greater Caucasus and in the foothills of the Kura depression and in adjacent waters of the Caspian Sea. Mud volcanoes are located mainly within the mobile belts of the globe with a high level of seismic activity, the intensity values of speeds of neotectonic and contemporary movements, etc. For seismically active zones are rifts and subduction zones, and the second the most active areas. As is well known, the zone associated with oil and gas well above the crust elements. On the other hand, all the mud volcanic and seismic phenomena are confined to fault zones of different depths of burial and age, which on one hand are conducting channels, on the other screens for hydrocarbon accumulations. High seismic area of mud volcanoes may be considered zones of hydrocarbon accumulations.

A geochemical study was carried out on gas, water and mud samples from four mud volcanoes in Gorgan Plain, SE Caspian Sea (Iran) in order to investigate fluid primary sources and secondary processes controlling fluid chemistry. The chemical composition of light alkanes and the isotopic feature of methane indicated an origin related to a thermogenic source. Gases discharged from Neftlijeh evidenced anaerobic biodegradation processes with addition of secondary microbial methane. Chemical composition of discharged waters revealed two main groups i) brine-type Na+–Cl− waters from Gharenyaregh and Neftlijeh mud volcanoes, which were marked by relatively high Na+/Cl−, B/Cl− and Li/Cl− ratios and low Ca2+/Cl−, Mg2+/Cl− and K+/Cl− ratios, ii) waters from Sofikam and Inche, characterized by relatively low Na+/Cl−, B/Cl− and Li/Cl− ratios and relatively high Ca2+/Cl−, Mg2+/Cl− and K+/Cl− ratios. The chemical and isotopic characteristics of the discharged waters suggest that evaporated Caspian seawater trapped in sediments is likely representing a reliable water source. The maximum formation depth at Gharenyaregh and Neftlijeh mud volcanoes were estimated at about 6 km depth whereas the generation depth of the rest was significantly shallower. Thus, the observed compositional differences can be related to the different depths of the fluid source feeding them.

В статье представлена характеристика биогеоценозов, а также определены геохимические показатели и медико-бальнеологический потенциал грязевулканических проявлений в долине «Источники Дачные» на юге Камчатского края. Определены валовые концентрации 9 оксидов и 12 химических элементов в сопочной глине площадки грязепроявлений севернее Мутновской геоТЭС. Отмечено богатство образцов грязевулканической брекчии органическими веществами, Al2O3, P2O5, хромом, серой, ванадием, в сопоставлении с эталонно-фоновыми образцами. Выявлена ландшафтно-геохимическая уникальность рассматриваемой территории и необходимость зарегулирования туристско-бальнеологической активности на ней., The article presents the characteristics of biogeocenoses, as well as the geochemical indicators and medical and balneological potential of mud-volcanic manifestations in the valley «Springs Dachnye» on the south of the Kamchatka peninsula. The total concentrations of 9 oxides and 12 chemical elements in the clay of the mud-bearing site, situated on the north of the Mutnovskaya geothermal power station, were determined. The richness of samples of mud-volcanic breccia with organic substances, Al2O3, P2O5, chromium, sulfur and vanadium, in comparison with background samples, is noted. The landscape and geochemical uniqueness of the described territory and the need to regulate tourist and balneological activity on it are revealed.

The shallowest sediment of three mud volcanoes (MVs) located in the middle slope of the Gulf of Cadiz, Anastasya, Pipoca and St. Petersburg, have been seasonally studied during June and December 2016. These structures are locally important contributors of many biogeochemical active substances to the water column, with a special attention in the emission of methane (CH4). Along this study, the role of organic matter diagenesis and its contribution to the diffusive fluxes estimated in the sediment–water interface from the three MVs have been investigated mainly. For this, the first combined analyses of sediment properties (granulometry, porosity, density, organic carbon) and pore water chemistry (major elements, dissolved inorganic carbon (DIC), nutrients, CH4 and nitrous oxide) have been carried out. Anastasya and St. Petersburg MVs presented similar behaviours, with a slight concentration variation for the chemical variables in the top layers of the sedimentary record followed by a more intense vertical variation in deeper layers. Anastasya MV showed some typical processes of these structures, such as the clay dehydration, the dissolution of halite and the precipitation of authigenic carbonates, which was also observed in St. Petersburg MV. Organic matter diagenesis clearly altered the biogeochemical profiles, except for Pipoca MV. Moreover, mud breccia with a mousse-like texture has been identified in the deepest levels of Anastasya and St. Petersburg MVs. Here, anaerobic oxidation of methane is linked to the decrease of $${\mathrm{SO}}_{4}^{2-}$$ and the increases of CH4 and DIC with the core depth. Changes across the sediment–water interface presented low diffusive fluxes in the three MVs due to the presence of other processes as the irrigation by benthic macrofauna, the action of bottom currents and/or the upward fluid migration. From the obtained results, we can conclude that Anastasya MV presents a certain venting activity at present.

In 2012, the canton of Geneva and the SIG (Services Industriels de Genève) started the Geothermie2020 program, aiming to exploit geothermal energy in the Greater Geneva Basin (GGB), Western Switzerland. Before the geothermal drilling operations start, it is key to know the local microseismicity, its relationship with local faults and their activation state. It is also important to ensure that the possible microseismicity can always be detected and located throughout the geothermal project. For this reason, a dense seismic network with sufficient sensitivity to monitor and control the seismicity levels in case of an unexpected event. In 2016, only two seismic stations were deployed in the basin, reaching a magnitude of completeness of 1.8-2.0. I deployed a temporary seismic network of 20 broadband stations around and within the Greater Geneva Basin for over 1.5 years (August 2016 - January 2018), lowering the magnitude of completeness to 0.5. This network served two purposes: to assess the seismotectonics of the basin and to perform an ambient-noise tomography study. We retrieved a new local 1D velocity model, with respective station corrections from the local earthquakes detected at the stations. The depth of the events increased after the relocation with the new model, indicating that the local faults might be deeper than expected. Newly computed focal mechanisms were used for a stress inversion. The stress inversion results show that the strike-slip faults that offset the basin are sub-parallel to the principal stress component, sigma 1, implying that these faults are currently active or prone to be re-activated. During the future exploitation of geothermal resources in the GGB, various types of microseimic events may be detected. Among them, weak emergent events with complex waveforms can occur (e.g., Larderello-Travale Geothermal Field, Italy). To locate such unconventional events, I developed a specifically designed location tool. The tool uses the cross-correlation of signals at different station pairs to provide a likelihood source location. The code was tested and applied to seismic signals associated with well-drilling operations in Larderello (Italy), LP events at magmatic volcanoes (Costa Rica) and drumbeat signals generated at mud volcanoes. I applied some of the previous techniques to identify, characterize and locate weak drumbeat signals at the at the Nirano Mud Volcano Field (Italy). I located the signals using the newly developed location tool and considering the seismic velocities that I locally retrieved with active seismic experiments. I used the drumbeat signals and V/H ratios to study the activity and evolution of the system. I found a correlation between the presence of the drumbeats and morphological changes, suggesting that the drumbeat signals can be used to access and monitor the evolution of the Nirano mud plumbing system.

This paper presents the investigation results of geodynamic, geothermal and geochemical conditions of gas emission zones in the anoxic Black Sea Basin. Gases are manifested in the form of seeps, fountains, mud volcanoes (MV), gas hydrates and authigenic carbonates. Several thousand gas seeps and more than 80 MVs have been found in the Black Sea Basin. Most of them are associated with fault zones, abyssal fractures, shale diapir and others zones of neo-tectonic activity. Gas seeps occur mostly on the outer shelf and in the upper part of continental slope (at a depth of 50—800 m), and MVs are distinguished in the central and the most submerged part of the Western Black Sea sub-basin, as well as in the periphery troughs. Gas hydrates occur in subsurface sedimentary layers near MVs and gas seeps at a water depth of more than 700 m. Methane is the dominant component among natural gases (90—95 %) from seeps and MVs. Methane homologous, carbon dioxide, hydrogen sulphide, nitrogen etc. are also present in different proportions. Breccia from MVs also contains oil components, different minerals (carbonates, sulphides, sulphates, phosphates) and dispersed particles of native metals. Based on seismic refraction data, the feeder channels of MVs penetrate to the base of Maykop sediments or to the Mesozoic basement (at a depth of 10—16 km). An analysis of the isotopic composition of methane from different sources (sediments, seeps, MVs and authigenic carbonates) has been performed. The stable carbon isotopic composition values (13C) range from -90 ‰ to -30 ‰ in methane and from -46.9 ‰ to - 8.5 ‰ in carbonates. Carbon isotopic composition in methane depends on its origin (organic or anorganic), as well as on thermodynamic conditions of its formation and migration. Changes in these conditions are accompanied by changes in chemical composition of hydrocarbon gases (from СО2 to СН4), as well as by isotopic composition fractionation of their components. These changes are possible only under mantle conditions. Heterogeneity of carbon isotopic composition in methane of the Black Sea Basin represents the variety of terms of its formation and is coherent with geotectonic zoning at the level of basement, as well as with peculiarities of geodynamic and geothermal conditions. Such coherence attests a significant (maybe even critical) role of abyssal processes in Earth degassing.Based on comprehensive analysis of manifestation peculiarities of gas emission, chemical and isotopic composition of carbon gases, as well as of geodynamic and geothermal conditions, it can be assumed that methane in the Black Sea Basin seems to be a product of the mixture in variable proportions of methane of different origin with distinct carbon isotopic composition: microbiogenic in near bottom layer of sediments, thermogenic in sedimentary layer and abyssal, entered through the fault zones from mantle in the form of fluid-and-gas flows. Hydrocarbon formation takes place under certain thermodynamic conditions (250, Приведены результаты исследований геодинамических, геотермических и геохимических условий зон газовой эмиссии в анаэробном бассейне Черного моря. Выделение газа в осадочной толще и на ее поверхности проявляются в форме фонтанов, сипов, грязевых вулканов, газовых гидратов, аутигенных карбонатов. В Черноморском бассейне выявлено несколько тысяч газовых сипов и свыше 80 грязевых вулканов. Они находятся преимущественно в зонах тектонических нарушений, глубинных разломов, глиняных диапиров и других проявлений неотектонической активности. Большинство газовых сипов концентрируется на внешнем шельфе и в верхней части континентального склона (в интервале глубин 50—800 м), а грязевые вулканы — в центральной, наиболее погруженной части Западно-Черноморского суббассейна и в периферических прогибах. Газовые гидраты фиксируются вблизи газовых сипов и грязевых вулканов в приповерхностном шаре осадков на глубине моря свыше 700 м. Среди газов преобладает метан (90—95 %). В качестве примесей отмечаются также гомологи метана, диоксид углерода, сероводород, азот и др. В брекчии грязевых вулканов содержатся нефтепродукты, разные минералы (карбонаты, сульфиды, сульфаты, фосфаты), дисперсные частички самородных металлов. По сейсмическим данным подводящие каналы грязевых вулканов проникают к основанию майкопских отложений и в некоторых случаях к мезозойскому фундаменту (до глубин 10—16 км).Проанализирован изотопный состав метана из разных источников (осадков, сипов, грязевых вулканов и аутигенных карбонатов). Показатель изотопного состава углерода (δ13С) изменяется от -90 до -30 в метане и от -46,9 до -8,5 ‰ в карбонатах. Изотопный состав углерода в метане зависит от его происхождения (органического или неорганического), термодинамических условий образования и миграции. Изменение этих условий сопровождается изменением химического состава углеродсодержащих газов (от СО2 до СН4) и фракционированием изотопного состава их компонентов. Такие изменения возможны только в мантийных условиях. Гетерогенность изотопного состава углерода в метане Черноморского бассейна отображает разнообразие условий его образования и согласуется с геотектоническим районированием на уровне фундамента и особенностями геодинамического и геотермического режима. Такая согласованность свидетельствует о значительной (если не решающей) роли глубинных процессов в дегазации Земли.По результатам комплексного анализа особенностей проявлений газовой эмиссии, химического и изотопного состава углеродных газов, геодинамических и геотермических условий можно сделать предположение, что метан в Черноморском бассейне является продуктом смешивания в изменяющихся пропорциях метана разного происхождения с отличающимся изотопным составом углерода: микробиогенного в придонном шаре осадков, термогенного в осадочном шаре и глубинного, который поступает по разломным зонам из мантии в виде флюидогазовых потоков. Образование углеводородов происходит при определенных термодинамических условиях (250, Наведено результати дослідження геодинамічних, геотермічних і геохімічних умов зон газової емісії в анаеробному басейні Чорного моря. Виділення газу в осадовій товщі і на її поверхні виявляються у вигляді фонтанів, сипів, грязьових вулканів, газових гідратів, аутигенних карбонатів. У Чорноморському басейні виявлено декілька тисяч газових сипів і понад 80 грязьових вулканів. Вони розміщуються переважно в зонах тектонічних порушень, глибинних розломів, глиняних діапірів та інших проявів неотектонічної активності. Більшість газових сипів концентруються на зовнішньому шельфі та у верхній частині континентального схилу (в інтервалі глибин 50—800 м), а грязьові вулкани — у центральній, найбільш зануреній частині Західночорноморського суббасейну і в периферійних прогинах. Газові гідрати трапляються поблизу газових сипів і грязьових вулканів у приповерхневому шарі осадів за глибини моря понад 700 м. Серед газів переважає метан (90—95 %). Як домішки зафіксовано також гомологи метану, діоксид вуглецю, сірководень, азот та ін. У брекчії грязьових вулканів містяться нафтопродукти, різні мінерали (карбонати, сульфіди, сульфати, фосфати), дисперсні частинки самородних металів. За сейсмічними даними підвідні канали грязьових вулканів проникають до підошви майкопських відкладів або мезозойського фундаменту (до глибин 10—16 км).Проаналізовано ізотопний склад метану із різних джерел (осадів, сипів, грязьових вулканів та аутигенних карбонатів). Показник ізотопного складу вуглецю (δ13С) змінюється від -90 до -30 ‰ у метані і від -46,9 до -8,5 ‰ у карбонатах. Ізотопний склад вуглецю у метані залежить від його походження (органічного чи неорганічного), термодинамічних умов утворення та міграції. Зміна цих умов супроводжується зміною хімічного складу вуглеводневих газів (від СО2 до СН4) і фракціонуванням ізотопного складу їх компонентів. Такі зміни можливі лише в мантійних умовах. Гетерогенність ізотопного складу вуглецю в метані Чорноморського басейну відображає різноманітність умов його утворення і узгоджується з геотектонічним районуванням на рівні фундаменту та особливостями геодинамічного й геотермічного режиму. Така узгодженість свідчить про значну (якщо не вирішальну) роль глибинних процесів у дегазації Землі.За комплексним аналізом особливостей вияву газової емісії, хімічного та ізотопного складу вуглецевих газів, геодинамічних і геотермічних умов можна припустити, що метан у Чорноморському басейні є продуктом змішування в змінних пропорціях метану різного походження з відмінним ізотопним складом вуглецю: мікробіогенного у придонному шарі осадів, термогенного в осадовому шарі й глибинного, що надходить по розломних зонах із мантії у вигляді флюїдогазових потоків. Вуглеводні утворюються за певних термодинамічних умов (250

Historical earthquakes such as the 1755 Lisbon earthquake and tsunami demonstrated that the plate boundary between Eurasia and Africa constitutes a significant earthquake and tsunami threat to neighboring coastal communities. Cruise M149 of R/V Meteor aimed at collecting short and long sediment cores and installing borehole observatories with the seafloor drill rig MARUM-MeBo70 (Meeresboden-Bohrgerät) to obtain records of the past and current tectonic activity of the plate boundary in the Gulf of Cadiz and Alboran Sea (W Mediterranean Sea). The cruise focused on 1) two NNW-SSE trending strike-slip faults (Lineament Center and South) cutting through the Gulf of Cadiz accretionary prism, 2) two SW-NE trending strike-slip faults in the Alboran Sea, and 3) adjacent mud volcanoes that are supposed to be hydraulically connected to deeper levels of the fault zones and plates interface. From July 24 to August 24, 2018, the M149 cruise collected in total 383.2 m of core, conducted 38 in situ heat flow measurements, mapped approximately 12500 km2 of seafloor and installed 3 borehole observatories. Three new mud volcanoes were discovered during the cruise (and at least two more supposed buried), of which one is located on the SW edge of the accretionary prism - outside of the predominant mud volcano distribution. We also re-visited various small mud volcanoes (Meknes, Rabat, El Cid, Almanzor) and the known Yuma and Ginsburg in the Gulf of Cadiz where we installed one of the borehole observatories at Ginsburg. Two further observatories were installed into strike-slip-faults – one in the Gulf of Cadiz and the other in the Alboran Sea. Thus, the M149 cruise fulfilled its primary objective of collecting long and short term records (i.e. sediment cores) of the tectonic activity associated with the plate boundary between Eurasia and Africa offshore SW Europe, which will provide the basis for further post-cruise research.

Este artículo contiene 25 páginas, 3 tablas, 14 figuras., Mud volcanoes are singular seafloor structures classified as ‘sensitive habitats’. Here we report on the sponge fauna from a field of eight mud volcanoes located in the Spanish margin of the northern Gulf of Cadiz (North-eastern Atlantic), at depths ranging from 380 to 1146 m. Thirty-eight beam-trawl samplings were conducted (covering over 61,000 m2) from 2010 to 2012, in the frame of a EC-LIFE + INDEMARES grant. A total of 1659 specimens were retrieved, belonging to 82 species, from which 79 were in the Class Demospongiae and three in Hexactinellida. Two species were new to science (Jaspis sinuoxea sp. nov.; Myrmekioderma indemaresi sp. nov.) and three others recorded for the first time in the Atlantic Ocean (Geodia anceps, Coelosphaera cryosi and Petrosia raphida). Five additional species were ‘Atlantic oddities’, since this study provides their second record in the Atlantic Ocean (Lanuginella cf. pupa, Geodia cf. spherastrella, Cladocroce spathiformis, Cladocroce fibrosa and Haliclona pedunculata). Basic numerical analyses indicated a significant linear relationship between the species richness per m2 and the number of sponge individuals per m2, meaning that in most volcanoes many species occur in equivalent, moderate abundance. Likewise, sponge species richness increased with depth, while the abundance of hard substrata resulting from carbonate precipitation and the fishing activities around the volcanoes had no detectable effect on the sponge fauna. However, in the latter case, a negative trend – lacking statistical support – underlaid the analyses, suggesting that a more extensive sampling would be necessary to derive more definitive conclusions in this regard., This research has benefited from funds of two grants of the European Community (LIFE + INDEMARES 07/NAT/E/000732 and INTEMARES LIFE15 IPE/ES/000012) awarded to co-authors at the IEO. Likewise, this research has benefited from funds of a Spanish Ministry of Economy and Competitiveness grant (MINECO– CTM2015-6722-1R) and a European Union Horizon 2020 SponGES (no. 679849) grant awarded to the CEAB-CSIC.

Between August and November 2016, three major earthquake events occurred in Central Italy. The first event, with M6.1, took place on 24 August 2016, the second (M5.9) on 26 October, and the third (M6.5) on 30 October 2016. Each event was followed by numerous aftershocks. The 24 August event caused massive damages especially to the villages of Arquata del Tronto, Accumoli, Amatrice, and Pescara del Tronto. In total, there were 299 fatalities, generally from collapses of unreinforced masonry dwellings. The October events caused significant new damage in the villages of Visso, Ussita, and Norcia, although not producing fatalities, since the area had largely been evacuated. The Italy-US Geotechnical Extreme Events Reconnaissance team investigated earthquake effects on slopes, villages, and major infrastructures. The approach adopted to carry out post-earthquake reconnaissance surveys was to combine traditional reconnaissance activities of on-ground evidences and mapping of field conditions with advanced imaging and damage detection routines enabled by state-of-the-art geomatics technology. Presented herein are the outcomes of the post-event reconnaissance surveys conducted after both the August main shock and the October events, focusing on geotechnical aspects, such as earthquake-triggered slope failures, mud volcanoes, performance of different geotechnical structures (i.e., dams, retaining walls, rockfall barriers, road embankments) and building damage patterns related to site amplification.

Subsurface gas hydrates over all the area of their potential occurrence under the floor of Lake Baikal, the only freshwater body where they occur, have been sought and studied since 2000. Two of three known gas hydrates cubic structures (structure 1 biogenic methane hydrates and structure 2 biogenic methane and thermogenic ethane hydrates) have been found in the lake sediments. Large autogenic carbonaceous formations atypical for the lake have been discovered in the areas of gas hydrates occurrence. A new so-called “Baikal” mud volcanoes formation mechanism with shallow roots previously unknown in the seas is described. This mechanism is related to destruction of gas hydrates under their stability zone due to a tectonic activity and warm fluid income. The focus and source of the gas-saturated fluid are determined to be buried depositions of delta fronts, depocenters in the middle of the basins and subsurface ancient sedimentation masses at the eastern flank. The 2018 integrated geological and geophysical survey allowed to discover 54 hydrate-bearing structures represented by 26 mud volcanoes, 18 hydrate mounds, 9 seeps and 1 pockmark. Not only sedimentation masses of various age and many kilometers thick, but also the tectonic dislocation grid determine the distribution of these structures on the floor of Lake Baikal. The fluid pathways are formed through impaired vertical and gently inclined zones of the main rift faults and secondary faults as well as along permeable lithological sedimentation boundaries when the layers rise from the depocenters in the center of the basin to its flanks.

The data presented in this article is related to the Master thesis; entitled âSurvey Aerobic Microbial Diversity Mud Volcanoes in Chabahar and Khash Ports in Southern Iranâ by the first author of this article, year 2011, Islamic Azad University, Iran (reference number (Parsia, 2011) [1] of this article). This article shows microbial biodiversity and evaluates bio-emulsifier and bio-demulsifier abilities of capnophile isolates, in order to introduce a superior isolate for the Microbial Enhanced Oil Recovery (MEOR) process in the petrochemical industry. Keywords: Mud volcanoes, Biodiversity, Bio-emulsification, Bio-demulsification, Petrochemistry

The concentration of CH in water was measured along five transects in the Gulf of Cadiz (Trafalgar, Sancti Petri, Guadalquivir, Tinto - Odiel and Guadiana) during four cruises throughout the months of March, June, September and December 2016. For two of the cruises water overlying three mud volcanoes situated in the Gulf of Cadiz were also sampled (San Petersburgo, 860 m; Pipoca, 460 m; and Anastasya, 500 m. In addition, the stable carbon isotopic compositions of dissolved CH (δC) were measured in the study area in June and December 2016. The mean CH value for the whole water column was 10.5 ± 4.3 nmol L, with large spatial and temporal variations. The highest values were found in June 2016 and the lowest in March 2016. In surface waters, the mean dissolved methane concentration was of 9.6 ± 2.6 nmol L. In most of the sampling area, high concentrations of CH were found in subsurface waters at depths close to the thermocline and at the coastal stations. The highest concentrations were obtained from the bottom waters above the Anastasya mud volcano (125 nmol L). The stable carbon isotope compositions ranged between - 29.2 and - 58.4‰, and the least negative values were associated with the highest CH concentrations in samples from above the mud volcanoes, related to thermogenic values. The sea-air fluxes of CH ranged from 12.4 to 37.7 μmol m d, showing that the study area acts as a source of CH to the atmosphere., A. Sierra was financed by the Spanish Ministry of Education with a FPU fellowship (FPU2014-04048) and M.D. Jiménez-López was financed by the University of Cádiz with a FPI fellowship (FPI-UCA). We thank the crews of the R/V's Angeles Alvariño and Ramon Margalef for their assistance during field work. This study was supported by the Spanish CICYT (Spanish Program for Science and Technology) under contract CTM2014-59244-C3-1-R.

Актуальность темы обуславливается проявлением в последнее время повышенного интереса ряда развитых стран к природным энергетическим ресурсам Черного моря. Преобладающий интерес в первую очередь вызывают гигантские углеводородные запасы и неисчерпаемые ресурсы сероводорода Черноморского бассейна. В данной работе рассмотрен энергетический потенциал Черного моря, а именно: газовые струи, газ грязевых вулканов, метан и сероводород. Составлена схема для изучения геоэкологической безопасности Черноморского бассейна. Проведен анализ влияния энергетических ресурсов на экологическую обстановку моря. Исследованы разделы геологии, тектоники, сейсмичности Черноморского региона, а также источники выделения газов на дне моря.

The Iberian margin in the Gulf of Cádiz hosts a fluid venting area embedded into a contourite depositional drift and is a natural laboratory to study how multiple interacting processes shape the seafloor. A high-resolution morpho-sedimentary analysis, based on geophysical data, sediment samples and submarine imagery, has been carried out; the onset and evolution of the main geoforms are discussed; and the influence of geological, oceanographic and biogenic processes conditioning substrate types and benthic community distribution are evaluated. The interplay of geological (e.g., salt and shale diapirism, mud volcanism), oceanographic (e.g., water mass circulation, secondary circulation, vertical eddies, internal waves) and biogenic (e.g., methane derived authigenic carbonates formation, coral mound aggradations) processes drive the formation of a large variety of geoforms including, among others, contourite drifts, channels, diapiric ridges, mud volcanoes, pockmarks, and coral mounds. At a smaller scale, the interaction between massive and fluid extrusive, biogenic, and bottom current-related processes (both depositional and erosive) determines the distribution of substrate types and benthic communities, which have been classified as belonging to different biotopes.

Este artículo contiene 20 páginas, 14 figuras, 5 tablas., The Mediterranean is a semi-enclosed sea, with a narrow natural connection —the Strait of Gibraltar— through its western basin to the North Atlantic. Many studies have investigated how the inflow of North Atlantic Surface water into the Mediterranean shapes the faunal composition and abundance of the shallow-water benthic communities of the Western Mediterranean. However, the reverse effect remains little explored, that is, at what level the relatively deep (>200 m deep) outflow of Mediterranean water (MOW) exports bathyal Mediterranean benthos into the North Atlantic and what is the fate of the exported fauna. In this study, we have investigated that process, using the bathyal sponge fauna known from a total of 9 biogeographical areas in the Northeastern Atlantic and 9 in the Western and Central Mediterranean, which accounted for a total of 456 spp. Prior to this general analysis, an exhaustive description of the bathyal sponge fauna (82 spp.) associated to 8 mud volcanoes located in the Gulf of Cadiz (Eastern North Atlantic) was conducted. This was necessary because the bathyal sponge fauna in the North Atlantic zone adjacent to the Strait of Gibraltar remained relatively poorly studied and that situation hindered relevant comparisons with the much better known bathyal fauna of the Western Mediterranean. The results of the clustering, ordination and regression analyses first revealed that the bathyal sponge fauna described from the mud volcanoes field in the Gulf of Cadiz was not essentially different from that previously described in pre-existing studies of other bathyal environments in the Gulf of Cadiz. The large scale subsequent assessment across the Atlantic-Mediterranean biogeographical gradient revealed that the sponge faunas of all Western Mediterranean areas form a relative cohesive group, except for the idiosyncratic nature of the Tyrrhenian Sea. More importantly, the deep-sea sponge fauna of the Gulf of Cadiz (in the easternmost Atlantic side of the Atlantic-Mediterranean gradient) showed more affinity with the fauna of the Western Mediterranean than with the fauna of the remaining Northeastern Atlantic areas considered in the study (i.e., Cape Verde, Canary Islands, Madeira, the Moroccan slope, Lusitanian Banks, Southern Azores Banks and Azores). The Mediterranean area with the highest faunal similarity to the Gulf of Cadiz was the Alboran Sea, followed by the Gulf of Lion, the Strait of Sicily and, the Gulf of Taranto, sharing collectively about 17% of their species. These patterns of faunal affinities clearly illustrate the importance of the MOW in transporting components of the Mediterranean deep-sea sponge communities towards the bathyal communities of the Gulf of Cadiz. The contrasting low faunal affinity between the deep-water sponge fauna of the Gulf of Cadiz and the remaining North Atlantic areas considered in the analyses also revealed that the Mediterranean faunal export is largely circumscribed to the Gulf of Cadiz. It is likely that the North-Atlantic trajectory of the MOW, turning north after the Strait of Gibraltar and staying attached to the slope of the Iberian margin, hinders subsequent colonization of the slopes of the Macaronesia region by the deep-water Mediterranean sponges exported to the Gulf of Cadiz. The results of this study, combined with previous literature on biogeographical sponge transport by marine currents, suggest that the sponge fauna provides a useful tool to reveal the future shifts in the biogeographic patterns predicted in our man-impacted and changing ocean., This research has benefited from funds of two grants of the European Community (LIFE + INDEMARES 07/NAT/E/000732 and INTEMARES LIFE15 IPE/ES/ 000012) awarded to co-authors at the IEO. Likewise, this research has benefited from funds of a Spanish Ministry of Economy and Competitiveness grant (MINECO– CTM2015-6722-1R) and a European Union Horizon 2020 SponGES (no. 679849) grant awarded to the CEAB-CSIC.

Clay dehydration at great depth generates fluids and overpressures in organic-rich sediments that can release isotopically light boron from mature organic matter, producing 10B-rich fluids. The B can be incorporated into the tetrahedral sites of authigenic illite during the illitization of smectite. Therefore, the crystal-chemical and geochemical characterization of illite, smectite or interlayered illite&ndash, smectite clay minerals can be an indicator of depth (temperature) and reactions with the basin fluids. The aim of this study was to determine the detailed clay mineralogy, B-content and isotopic composition in illite&ndash, smectite rich samples of mud volcanoes from the Gulf of C&aacute, diz, in order to evaluate interactions of hydrocarbon-rich fluids with clays. Molecular modeling of the illite structure was performed, using electron density functional theory (DFT) methods to examine the phenomenon of B incorporation into illite at the atomic level. We found that it is energetically preferable for B to reside in the tetrahedral sites replacing Si atoms than in the interlayer of expandable clays. The B abundances in this study are high and consistent with previous results of B data on interstitial fluids, suggesting that hydrocarbon-related fluids approaching temperatures of methane generation (150 &deg, C) are the likely source of B-rich illite in the studied samples.

The occurrence of mud volcanoes (MVs) in the deep Ionian Sea was first recognised in the early 1980s from the recovery of cores of mud breccia, initially hypothesised to record tectonic or diapiric processes, but eventually shown to record a long (> 1 Ma) history of seafloor extrusion from the accretionary prisms along the Europe-Africa subduction zone. Provinces of MVs were identified along the crest of the Mediterranean Ridge south and west of Greece, but few data were available from the Calabrian offshore until early in this century when new geophysical and geological data were acquired in the context of European-funded programmes. The acquisition of regional multibeam bathymetric and backscatter data, as well as seismic reflection profiles and cores from selected features, resulted in the discovery of a new province of MVs on the Calabrian accretionary prism (CAP), as well as insights into their activity through time. A total of 54 MVs were identified on the inner CAP across water depths of 150-2750 m from their distinctive morphologies and/or high backscatter character, in several cases proven by coring. Seismic reflection grids across two proven MVs showed them to record a history of activity dating back to an interpreted mid-Pliocene unconformity, one of the longest known records of extrusion. Sediment cores indicate recurrent eruptive episodes during the last glacial-interglacial cycle (, La presenza di vulcani di fango (MV) nelle acque profonde del Mar Ionio è stata riconosciuta all’inizio degli anni ’80 dalla presenza di brecce di fango in carotaggi. Inizialmente si era ipotizzato che questa litologia indicasse processi tettonici o diapirici, mentre successivamente la sua genesi è stata attribuita ad un lungo (> 1 Ma) processo di estrusione sul fondo marino avvenuto nei prismi di accrezione nella zona di subduzione Europa-Africa. Province di MV sono state identificate lungo la cresta del Mediterranean Ridge a sud e a ovest della Grecia, ma pochi dati relativi all’offshore calabrese sono stati disponibili fino all’inizio di questo secolo, quando nuovi dati geofisici e geologici sono stati acquisiti nel contesto di programmi finanziati dall’UE. L’acquisizione dei dati batimetrici e di backscatter multibeam, così come profili di sismica a riflessione e carotaggi hanno portato alla scoperta di una nuova provincia di MV sul prisma di accrezione calabrese (CAP), insieme a informazioni sulla loro attività nel tempo. Sulla CAP interna sono stati identificati 54 MV, a profondità comprese tra 150 e 2750 metri, identificati sulla base delle caratteristiche morfologiche e/o dell’elevato backscatter, supportati in diversi casi da carotaggi. Le registrazioni sismiche eseguite in corrispondenza di due MV hanno mostrato tracce di attività risalente a una discordanza del Pliocene medio, uno dei record di estrusione fra i più antichi. I campioni di sedimento indicano episodi eruttivi ricorrenti durante l’ultimo ciclo glaciale-interglaciale (

Terrestrial mud volcanoes are unique structures driven by tectonic pressure and fluids from the deep subsurface. These structures are mainly found in active tectonic zones, such as the area near the Los Bajos Fault in Trinidad. Here we report a chemical and microbiological characterization of three mud volcanoes, which included analyses of multiple liquid and solid samples from the mud volcanoes. Our study confirms previous suggestions that at least some of the mud volcano fluids are a mixture of deeper salt-rich water and surficial/precipitation water. No apparent water quality differences were found between sampling sites north and south of a major geological fault line. Microbiological analyses revealed diverse communities, both aerobic and anaerobic, including sulfate reducers, methanogens, carbon dioxide fixing and denitrifying bacteria. Several identified species were halophilic and likely derived from the deeper salt-rich subsurface water, while we also cultivated pathogenic species from the Vibrionaceae, Enterobacteriaceae, Shewanellaceae, and Clostridiaceae. These microorganisms were likely introduced into the mud volcano fluids both from surface water or shallow ground-water, and perhaps to a more minor degree by rain water. The identified pathogens are a major health concern that needs to be addressed.

Azooxanthellate cold-water corals (CWCs) have a global distribution and have commonly been found in areas of active fluid seepage. The relationship between the CWCs and these fluids, however, is not well understood. This study aims to unravel the relationship between CWC development and hydrocarbon-rich seepage in Pompeia Province (Gulf of Cádiz, Atlantic Ocean). This region is comprised of mud volcanoes (MVs), coral ridges and fields of coral mounds, which are all affected by the tectonically driven seepage of hydrocarbon-rich fluids. These types of seepage, for example, focused, scattered, diffused or eruptive, is tightly controlled by a complex system of faults and diapirs. Early diagenetic carbonates from the currently active Al Gacel MV exhibit δ13C signatures down to −28.77 ‰ Vienna Pee Dee Belemnite (VPDB), which indicate biologically derived methane as the main carbon source. The same samples contain 13C-depleted lipid biomarkers diagnostic for archaea such as crocetane (δ13C down to −101.2 ‰ VPDB) and pentamethylicosane (PMI) (δ13C down to −102.9 ‰ VPDB), which is evidence of microbially mediated anaerobic oxidation of methane (AOM). This is further supported by next generation DNA sequencing data, demonstrating the presence of AOM-related microorganisms (ANMEs, archaea, sulfate-reducing bacteria) in the carbonate. Embedded corals in some of the carbonates and CWC fragments exhibit less negative δ13C values (−8.08 ‰ to −1.39 ‰ VPDB), pointing against the use of methane as the carbon source. Likewise, the absence of DNA from methane- and sulfide-oxidizing microbes in sampled coral does not support the idea of these organisms having a chemosynthetic lifestyle. In light of these findings, it appears that the CWCs benefit rather indirectly from hydrocarbon-rich seepage by using methane-derived authigenic carbonates as a substratum for colonization. At the same time, chemosynthetic organisms at active sites prevent coral dissolution and necrosis by feeding on the seeping fluids (i.e., methane, sulfate, hydrogen sulfide), allowing cold-water corals to colonize carbonates currently affected by hydrocarbon-rich seepage.

В статье рассматриваются валовые концентрации и водорастворимые формы лантаноидов в сопочной глине грязевых вулканов Крыма и в майкопских глинах. В сопочной глине отмечаются повышенные концентрации ряда лантаноидов. Приводится нормирование лантаноидов в сопочных и майкопских глинах к их содержаниям в хондрите, глинах Русской платформы, к верхней части земной коры и нефти. Рассчитан массоэлементоперенос лантаноидов с сопочной грязью в прилегающие ландшафты., The article considers gross concentrations and water-soluble forms of lanthanides in the volcanic clay of the mud volcanoes of the Crimea and in the Maikop clays. Elevated concentrations of a number of lanthanides are observed in the volcanic clay. The article gives information of valuation of lanthanides in the volcanic and Maikop clays to their contents in chondrite, clays of the Russian platform, to the upper part of the earth's crust and oil. Mass transfer of elements of lanthanides with volcanic mud in the surrounding landscapes is calculated., №1(33) (2019)

Mud volcanoes are common in active mountain fronts. At Mt. Etna, located just between the Apennine front in Sicily and its foredeep, there are some manifestations of mud volcanism in the lower border of the volcanic edifice. The activity of these mud volcanoes is characterized by persistent emission of muddy water mixed with salts, which rises to the surface due to the gas pressure in the subsoil. The San Biagio Salinelle is one of the three mud volcano fields located around the Paterno eruptive monogenic apparatus; this old volcanic structure was one of the first subaerial volcanic manifestations that formed in the pre-Etnean phase. It is not fully clear whether and how the activity of the mud fields is connected with the volcanic activity of Mt. Etna. Noninvasive geophysical surveys were carried out in the area of the active cone of the San Biagio Salinelle, in order to identify the probable ascent path of the emitted products. Seismic ambient noise records were collected at the nodes of a specially designed grid and, subsequently, the V s values were obtained from an active seismic survey. A digital elevation model (DEM) of the area was obtained by a topographic survey, carried out with the GNSS technique (global navigation satellite system), in real-time kinematic mode. The DEM and the topographic benchmark installed will represent the reference surface for future periodic monitoring of the ongoing deformation in the area. Our results provide an accurate and detailed 3D subsurface model showing the shallower feeding system of the investigated mud volcano.

Active mud volcanism in the West Alboran Basin (WAB) is closely associated with tectonically mobilized, overpressurized shales and shale-diapirism. This appears to control mud expulsion at Carmen mud volcano, a cone-shaped structure 65 m high and 1 km in basal diameter. The presence of gas-rich mud breccia, living chemosynthetic fauna, the absence of hemipelagic draping and the abrupt transition that occurs between high dissolved sulfate in the uppermost interval and low sulfate together with high methane concentrations in the lowermost sediment interval all point to a recent expulsion of mud breccia at the summit of Carmen MV. For the lowermost interval, the depletion of major elements (i.e., Ca2+ and Mg2+) and the enrichment of trace species (i.e., Li and B) in the pore water all indicate a deep fluid source. The δ18Opw (5.7‰ VSMOW) and δDpw (−10‰ VSMOW) of pore water in the lowermost interval correspond with smectite dehydration as the main pore-water freshening mechanism. Water-formation temperatures calculated with empirical geo-thermometers (K-Na, K-Mg; δ18Opw, δDpw, and dissolved B) reveal that fluids were generated at temperatures of ~140 ± 20 °C. Taking a regional geothermal gradient for the WAB of 25–27 °C/km, this points to a fluid source from ~5 ± 1 km sediment depth. This is not only consistent with the depth of overpressurized shales and megabreccia of Lower to Middle Miocene age, but it also fits nicely with the Upper/Middle-Miocene seawater value for the porewater 87Sr/86Sr derived from dissolving carbonates. The stable carbon and hydrogen isotopic composition of methane (δ13Cmethane ~ −59.4‰ VPDB and δDmethane −184‰ VSMOW) for the deepest samples of summit-core GP05PC is consistent with the mentioned deep origin. Mud breccia expulsion of overpressurized deep sedimentary units would be accompanied by rigorous degassing, leading to rapid, ‘instantaneous’ replacement of pore fluid by bottom water in the upper sediments. The absence of oxidized sediment draping, the seawater-like pore-water composition in the uppermost part of the mud breccia interval, and the abrupt methane to sulfate transition all provide evidence for a very recent mud expulsion. The distinctively kink-shaped pore-water Cl− profile in core GP05PC has been used in a numerical transport-reaction model to derive the timing for this event. This eruptive event appears to have taken place very recently, namely 12 ± 5 yrs prior to the 2012 coring, thus in the year 2000 CE.

The Iberian margin in the Gulf of Cádiz hosts a fluid venting area embedded into a contourite depositional drift and is a natural laboratory to study how multiple interacting processes shape the seafloor. A high-resolution morpho-sedimentary analysis, based on geophysical data, sediment samples and submarine imagery, has been carried out; the onset and evolution of the main geoforms are discussed; and the influence of geological, oceanographic and biogenic processes conditioning substrate types and benthic community distribution are evaluated. The interplay of geological (e.g., salt and shale diapirism, mud volcanism), oceanographic (e.g., water mass circulation, secondary circulation, vertical eddies, internal waves) and biogenic (e.g., methane derived authigenic carbonates formation, coral mound aggradations) processes drive the formation of a large variety of geoforms including, among others, contourite drifts, channels, diapiric ridges, mud volcanoes, pockmarks, and coral mounds. At a smaller scale, the interaction between massive and fluid extrusive, biogenic, and bottom current-related processes (both depositional and erosive) determines the distribution of substrate types and benthic communities, which have been classified as belonging to different biotopes., The authors thank colleagues, captains and crew members who participated in the data acquisition during the 2010–2019 expeditions aboard R/V Emma Bardán, R/V Cornide de Saavedra, R/V Ramón Margalef, and R/V Ángeles Alvariño. We are also grateful for the comments provided by the two anonymous reviewers, which significantly improved this manuscript. This work has been supported by LIFE+ INDEMARES/CHICA (LIFE 07/NAT/E/000732), ISUNEPCA (FB FEP/AC1 20123118_2014; IEO/2015-2017), LIFE IP PAF INTEMARES (LIFE15/IPE/ES/000012), INPULSE (CTM2016 75129 C3 1 R MINECO) and TALUS (CGL2015-74216-JIN) projects. Part of the research was also conducted within the framework of “The Drifters Research Group” at Royal Holloway, University of London (UK), and is related to the projects CTM 2012-39599-C03 and CGL2016-80445-R.

In this paper, we present the results of generalization and analysis of worldwide data on the isotope and chemical composition of gases from terrestrial mud volcanoes. In most cases, methane predominates in mud volcanic gases. The average concentration of methane is about 92.5 vol. %. The concentrations of heavy methane homologues are enough low, i.e. mud volcanic gases are dry. Nearly three-quarters of gas samples show the ethane concentration of less than 0.5 vol. %. We used data on the isotopic composition of carbon and hydrogen in methane to determine the genesis of mud volcanic gases. Methane is thermogenic origin in most mud volcanoes. The carbon isotopic composition of me-thane shows mainly the range from -60 to -25 ‰ PDB. We also see that the gases of many mud volcanoes correspond to the late stages of catagenesis. The results of our researches verify that mud volcanism is an indicator of the oil and gas prospects.

Onshore and offshore mud volcanism in the Makran accretionary prism is related to convergence of the Arabian and Eurasian plates. This study describes the chemical and isotopic composition of hydrocarbon-rich fluids from four active on-shore mud volcanoes located along the Makran coast (southern Iran), namely Borborok, Ain, Napag and Sand Mirsuban (Makran coast, southern Iran), as well as Pirgel mud volcano (SE Iran) that is located between the Taftan and Bazman igneous volcanoes. The main aim was to provide insights into the source region (s) of gases and waters discharged from these systems and the secondary processes controlling their chemical features. The four on-shore mud volcanoes emitted CH4-dominated gases, with significant concentrations of C2+ alkanes suggesting a dominant thermogenic origin, as confirmed by their delta C-13-CH4 values. Carbon dioxide was present at relatively low concentrations (0.78-2.33%) with an isotopic signature (delta C-13-CO2 from -34.2 to -11.1 parts per thousand vs. V-PDB) in the range of that typical of thermogenic gases. Hence, the geochemical features of these mud volcanoes point to the occurrence of a deep gas source rich in hydrocarbons, although the occurrence of an exploitable gas reservoir has to be confirmed by geophysical measurements and detailed geostructural surveys. Gas chemistry from Pirgel mud volcano completely differs with respect to that of the previous ones, since the former emits gases dominated by CO2 and showing relatively high R/Ra values (approximate to 1.6), suggesting a significant fluid contribution from the nearby volcanic systems. Moreover, waters from the on-shore mud volcanoes showed a Na-Cl composition, typically associated with mud volcanism, whereas those discharged from Pirgel were Na-HCO3-type and rich in chemical species typical of hydrothermal fluids such as As. Waters from the on-shore volcanoes were characterized by a strong delta O-18-positive shift and high B and Li concentrations, likely indicating clay mineral dehydration and long-term water-rock interaction. Such geochemical features were also shown by the waters from Pirgel, where the high concentrations of B and Li were possibly related to volcanic source. Estimated temperatures for the on-shore mud volcanoes estimated using the Mg-Li and Mg-K geothermometers range from 84 to 165 degrees C, corresponding to 3-7 km depth.

Active mud volcanism in the West Alboran Basin (WAB) is closely associated with tectonically mobilized, overpressurized shales and shale-diapirism. This appears to control mud expulsion at Carmen mud volcano, a cone-shaped structure 65 m high and 1 km in basal diameter. The presence of gas-rich mud breccia, living chemosynthetic fauna, the absence of hemipelagic draping and the abrupt transition that occurs between high dissolved sulfate in the uppermost interval and low sulfate together with high methane concentrations in the lowermost sediment interval all point to a recent expulsion of mud breccia at the summit of Carmen MV. For the lowermost interval, the depletion of major elements (i.e., Ca and Mg) and the enrichment of trace species (i.e., Li and B) in the pore water all indicate a deep fluid source. The δO (5.7‰ VSMOW) and δD (−10‰ VSMOW) of pore water in the lowermost interval correspond with smectite dehydration as the main pore-water freshening mechanism. Water-formation temperatures calculated with empirical geo-thermometers (K-Na, K-Mg; δO, δD, and dissolved B) reveal that fluids were generated at temperatures of ~140 ± 20 °C. Taking a regional geothermal gradient for the WAB of 25–27 °C/km, this points to a fluid source from ~5 ± 1 km sediment depth. This is not only consistent with the depth of overpressurized shales and megabreccia of Lower to Middle Miocene age, but it also fits nicely with the Upper/Middle-Miocene seawater value for the porewater Sr/Sr derived from dissolving carbonates. The stable carbon and hydrogen isotopic composition of methane (δC ~ −59.4‰ VPDB and δD −184‰ VSMOW) for the deepest samples of summit-core GP05PC is consistent with the mentioned deep origin. Mud breccia expulsion of overpressurized deep sedimentary units would be accompanied by rigorous degassing, leading to rapid, ‘instantaneous’ replacement of pore fluid by bottom water in the upper sediments. The absence of oxidized sediment draping, the seawater-like pore-water composition in the uppermost part of the mud breccia interval, and the abrupt methane to sulfate transition all provide evidence for a very recent mud expulsion. The distinctively kink-shaped pore-water Cl profile in core GP05PC has been used in a numerical transport-reaction model to derive the timing for this event. This eruptive event appears to have taken place very recently, namely 12 ± 5 yrs prior to the 2012 coring, thus in the year 2000 CE., This work was supported by MINECO Spanish Projects [CTM2009-07715, CGL2011-1441, CGL2012-32659 and CGL2015-66830-R]; and the Andalusian Government Research Group [RNM-179 and RNM-215]. C. F. López-Rodríguez was funded by a JAE-PhD fellowship from the CSIC (Spain); she acknowledges subsequent funding from the STSM in the framework of COST action ES1301.

A new distribution map of gas seeps and mud volcanoes has been compiled of the Black Sea. It has been derived from the published coordinates for ca. 5000 gas seeps and 80 mud volcanoes. An analysis of the stable isotopic composition of methane has been performed for authigenic carbonates and sediments. The δ13C values of carbonates and sediments form 2 distinct tight groups depending of the geological environments. The diagrams of values of δ13C vs. δD and δ13C vs. C1/(C2 + C3) have been applied to assess earlier classifications of methane. The origin of methane from most of samples has turned out to be uncertainly determined. Based on seismic reflection data, the feeder channels of gas releases and mud volcanoes penetrate to the Pre-Mesozoic basement beneath the Polshkov High, Andrusov and Tetyaev Ridges and Sorokin Trough at a depth of up to 12 km. In the Central Black Sea the feeder channel of mud volcano reaches the mantle surface where a depth is 19 km. The highest concentration of gas seeps distribution is observed at the triple junction of the mantle faults in the NW Black Sea. Assessments of different mechanisms have been made for their ability to produce an unprecedented methane concentration in the Black Sea water column. There occurs thermogenic methane in the sediments from gas seepage and mud volcanoes areas. The thermogenic methane results from post genetic alternation of biogenic methane of the Paleogene—Neogene sediments. Biological methane produced from organic matter plays negligibly small role in accumulating the world’s largest quantities of anaerobic methane in the Black Sea. Nonorganic methane is most likely to form the tremendous reservoir of dissolved gas in the Black Sea water column below 150—200 m. The seeming scarcity of abi-otic methane is accounted for its recycling by microbial activity, misclassificating origin and producing by chemical syntheses, with its biological methane δ13C values., Составлено новую карту выходов газа и грязевых вулканов в Черном море. Основу карты составляют опубликованы координаты около 5000 газовых выходов и 80 грязевых вулканов. Проанализированы стабильный изотопный состав метана для аутиген- них карбонатов и осадков. Изотоп 513C карбонатов и осадков образует две различные плотные группы в зависимости от условий геологической среды. Для оценки ранних классификаций метана применены диаграммы изменений значений 513 C в зависимости от значений 5 D и 513C и от отношений C1 / (C2 + C3). Оказалось, что происхождение метана большинстве образцов является неоднозначным. По данным сейсмического метода отраженных волн, питательные каналы газовых выбросов и грязевых вулканов проникают в передмезозойський фундамент под поднятием Полшков, хребтами Андрусове и Тетяево и прогибом Сороки- на на глубину до 12 км. В центре Черного моря питательный канал грязевого вулкана достигает поверхности мантии, где глубина составляет 19 км. Наибольшую концентрацию газовых выходов зафиксировано на тройном сочленении мантийных разломов в северо-западной части Черного моря. Оценен способность различных механизмов вызвать беспрецедентную концентрацию метана в водной толще Черного моря. В осадочных отложениях в районах выходов газов и грязевых вулканов распространенный термоген- ный метан - результат постгенетичного преобразования биогенного метана палео- ген-неогеновых отложений. Биологический метан, образующийся в результате переработки органического вещества, играет незначительную роль в накоплении большого в мире резервуара анаэробного метана в Черном море. Неорганический метан формирует огромное вместилище растворенного газа в водном столбе Черного моря глубже 150-200 м. Мнимую нищета абиогенного метана объясняем его рециркуляцией микробами, неправильной классификации происхождения и выработки химическим синтезом с изотопом 513C биогенного метана., Складено нову карту виходів газу і грязьових вулканів у Чорному морі. Основу карти складають опубліковані координати близько 5000 газових виходів і 80 грязьових вулканів. Проаналізовано стабільний ізотопний склад метану для аутиген- них карбонатів і осадів. Ізотоп 513C карбонатів і осадів утворює дві різні щільні групи залежно від умов геологічного середовища. Для оцінювання раніших класифікацій метану застосовано діаграми змін значень 513 C залежно від значень 5 D і 513C та від відношень C1/( C2 + C3). Виявилося, що походження метану більшості зразків є неоднозначним. За даними сейсмічного методу відбитих хвиль, живильні канали газових викидів і грязьових вулканів проникають у передмезозойський фундамент під підняттям Полшкова, хребтами Андрусова і Тетяєва і прогином Сорокі- на на глибину до 12 км. У центрі Чорного моря живильний канал грязьового вулкана досягає поверхні мантії, де глибина становить 19 км. Найбільшу концентрацію газових виходів зафіксовано на потрійному зчленуванні мантійних розломів у північно-західній частині Чорного моря. Оцінено здатність різних механізмів зумовити безпрецедентну концентрацію метану у водній товщі Чорного моря. В осадових відкладах у районах виходів газів і грязьових вулканів поширений термоген- ний метан — результат постгенетичного перетворення біогенного метану палео- ген-неогенових відкладів. Біологічний метан, утворений внаслідок переробки органічної речовини, відіграє незначну роль у накопиченні найбільшого у світі резервуара анаеробного метану в Чорному морі. Неорганічний метан формує величезне вмістище розчиненого газу у водному стовпі Чорного моря глибше 150—200 м. Уявну убогість абіогенного метану пояснюємо його рециркуляцією мікробами, неправильною класифікацією походження і вироблення хімічним синтезом з ізотопом 513C біогенного метану.

The mud volcanoes in the valley of the Sazliyka River and its tributaries are a geological phenomenon that has attracted scientific attention for decades. They are a specific element for the local lowland landscapes. This study focuses on the content of heavy metals in mud volcanoes. The total content of the elements: copper (Cu), zinc (Zn), lead (Pb), manganese (Mn), nickel (Ni), cobalt (Co) and chromium (Cr) in mg/kg (ppm) has been identified. The obtained contents have been analyzed by the clarke of concentration indicator (KK) - the ratio between the content of a given element in a given natural component (soil horizon, vegetation, surface water, etc.) - Ci, and a clarke of the same element in the lithosphere - K: The researched geochemical nature of the local litho-geochemical and soil-geochemical conditions may have been influenced by the geochemical specifics of the materials entering the earth’s surface upon activation of mud volcanoes in the area of study. They might have an impact on the geochemical structure of the bottom sediments in the local river currents and hence the influence on the main river artery Sazliyka River. The obtained results give to some extent information about the geochemical nature of this rare phenomenon for our country.

Since the early 80s, technological advances of seabed imagery and exploration of continental margins allowed to discover and study numerous seabed features recording fluid circulation within the sediment column.In this study of mud volcanoes, we propose an innovative method of analysis combining an automated statistical approach including detection and analysis of morphometric parameters together with a classical geological study. We used broad homogenous academic and industrial marine geophysical and geological dataset, at the scale of Eastern Mediterranean sea.The analysis of these parameters shows that the mechanism of formation of the mud volcanoes is directly related to a local or regional constrain that may have a tectonic or gravitational origin.Various geological parameters conditioning the size and shape of mud volcanoes have been studied and lead to propose an original model for the formation of mud volcanoes. The design of this model, which is intended to be generic, makes it possible to group the constituent parameters of a mud volcano system in three spatial stages, from the source layer to the superficial expression.; Depuis le début des années 80, les progrès technologiques de l'imagerie des fonds marins et l'exploration des marges continentales ont permis de découvrir et d'étudier de nombreuses morphologies du fond marin témoignant de la circulation des fluides dans la colonne sédimentaire et de leur expulsion. Dans cette étude des volcans de boue, nous proposons une méthode d'analyse innovante combinant une approche statistique automatisée incluant la détection et l'analyse de paramètres morphométriques avec une étude géologique classique. Nous avons utilisé un vaste jeu de données de géophysiques marines et géologiques, d’origines académiques et industrielles, à l’échelle du bassin oriental de la mer Méditerranée.Il ressort de cette analyse que le mécanisme de formation des volcans de boue est directement lié à une contrainte locale ou régionale pouvant avoir une origine tectonique ou gravitaire.Différents paramètres géologiques conditionnant les dimensions et formes des volcans de boue ont été étudiés permettant de proposer un modèle original de leur formation. La conception de ce modèle, qui se veut générique, permet de regrouper les paramètres constitutifs d’un système de volcan de boue en trois étapes spatiales, depuis la couche source jusqu’à l’expression superficielle.

Diapirs and mud volcanoes (MVs) are formed by the migration and extrusion of fluids and mud to the seafloor, respectively. In the Gulf of Cádiz there are ca. 60 MVs and several diapirs with different environmental conditions and seepage activity. Previous studies, mainly on MVs, have demonstrated that the invertebrate fauna associated with these seafloor structures can be very diverse, including chemosymbiotic species, mostly mollusks and frenulate polychaetes, as well as vulnerable suspension feeders, such as cold-water corals and sponges, among others. Previous studies of the bryozoan fauna in this area have recorded species belonging to 28 families. One of these families is Phidoloporidae, which comprises 27 genera worldwide, including the common Rhynchozoon, Reteporellina, and Reteporella. In the present study, two species belonging to Reteporella are redescribed, and a new species is described from diapirs and MVs on the shelf and slope of the Gulf of Cádiz. The samples were collected during several oceanographic expeditions carried out by the Instituto Español de Oceanografia. This genus is well represented in the NE Atlantic Ocean and the Mediterranean Sea, and our study extends its occurrence on MVs and diapirs fields of the Gulf of Cádiz.

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