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Recent studies, coordinated by the CNR-IGAG, have allowed us to discover a previously unknown active hydrothermal system off the coast of Zannone Island (western Pontine Archipelago, central Tyrrhenian Sea). Morphological features produced by hydrothermal activity include five, large-scale depressions (length >250 m) detected using multibeam data acquired by research vessels of the National Research Council (CNR, Italy). After this discovery, multidisciplinary investigations (geophysical, geochemical, micro-paleontological, mineralogica-petrographical, etc) were conducted within the framework of the Ritmare Project to define the processes that formed the depressions, to infer the origin of the fluids, and to explore the sub-seafloor architecture. The main focus was devoted to the most complex depression among the five: the Zannone Giant Pockmark - ZGP, which is characterized by several active fluid emissions. The ZGP represents a unique case in the Mediterranean of large-scale complex depression (0.5 km2) formed by numerous craters, mounds, and pockmarks associated with different types of emissions. To date, examples of similar hydrothermal morphologies are very rare (i.e., depression located offshore Panarea Island, MONECKE et alii, 2012; the Yellowstone Lake seafloor, MORGAN et alii, 2003), and their formation and evolution are not yet well understood (e.g., explosive hydrothermal activity, collapse, self-sealing, and alteration processes).

European Geosciences Union (EGU) General Assembly 2018, 8-13 April 2018, Vienna, Austria.-- 1 page, The upper continental slope off Capo Vaticano (Calabro-Tyrrhenian continental margin) is characterized by a contourite depositional system (postglacial elongated drifts) built by a northward-directed bottom current, likely similar to the present-day modified-LIW, outflowing from the Messina Strait. In this area, both along-slope and down-slope processes shaped the seafloor during the Late-Quaternary, producing a complex and dynamic environment. Here, the knowledge of sedimentary processes and controlling factors, particularly for contourite deposition is rather limited; nowadays, it is based only on high resolution seismic stratigraphy, whereas studies regarding the nature of contourite deposition and sedimentary facies are still lacking. In this study, we show preliminary results from the integrate analysis of sediment cores (visual description and grain size analysis) and high resolution seismic profiles, in order to reconstruct the shallow stratigraphy and to characterize contourite deposition during the postglacial period. The two gravity cores were collected at 153 and 156 m water depth, from drift and moat domains of an elongatedseparated drift. The sediment cores (2.30 m and 3.55 m long) recovered the uppermost part of drift deposit. They reveal the occurrence of intervals of sandy-silty layers or lenses embedded within muddy intervals. Sedimentary structures and vertical trend of grain-size suggest the occurrence of partial (e.g., topcut-out type) and complete (C1 to C5) contourite bi-gradational sequences, ca. 40-60 cm thick. Complete sequences characterize the drift domain, where three sequences can be recognized. In the moat domain, where seismic profiles indicate thin contourite facies separated by erosive/non depositional surfaces, the cored contourite interval is composed of silty-sandy laminae and pockets, dispersed in a muddy matrix, and by a basal layer of muddy fine sand. In this case, the subdivision of contourite deposits into classical sequences is not straightforward, however at least one sequence can be recognized. The integration of core data and seismic profiles indicate that sandy-silty intervals correlate with high-amplitude seismic reflectors observed on profiles crossing the drift. In contrast, muddy intervals correlate with transparent facies. Particularly, the homogeneous mud recovered in the first 1.15-1.3 m of the gravity cores is associated with a semi-transparent seismic facies possibly related to the highstand hemipelagic deposition. Seismic profiles also indicates that contourite deposits overlies a wedge-shaped infra-littoral prograding deposit, likely formed during the LGM period. Therefore it is proposed that contourite facies were deposited during the postglacial sea level rise, whereas hemipelagic mud dominated during the Holocene highstand. Both gravity cores and seismic stratigraphy show that contourite processes varied during the postglacial period. Based on this preliminary results and on ongoing studies on sediment composition and foraminiferal assemblages we will try to analyze the influence of climate/sea-level variations, variability of bottom current velocity/position and changes in sediment provenance on contourite deposition

Rock samples dredged offshore the Pontine Archipelago (400–2000 m water depth) were studied by palaeontological analyses of planktic foraminifera and endo-epilithozoan faunas colonising Fe–Mn crusts and by petrographic analyses of volcanic samples. Palaeontological and petrographic analyses have revealed a complex Plio-Pleistocene depositional history controlled by hemipelagic sedimentation and volcanic activity with episodic non-depositional phases. The sedimentary deposits are associated with ferromanganese hardgrounds, more or less colonised by endolithic and epilithozoan organisms. The presence of foraminifera typical of tropical and subtropical waters (such as Globigerinoides ruber , Globigerinoides trilobus , Pulleniatina obliquiloculata and Sphaeroidinella dehiscens ) indicates that the micritic deposition occurred during warm climatic periods, whilst micrite cementation and hardground formation are here attributed to colder climates. The depositional processes recognised on the Pontine continental slope reveal a sediment-starved condition that locally resemble those of seamount environment. The slope sedimentation found in the Pontine Archipelago can be helpful in the interpretation of ancient deposits from seamounts and continental slope depositional environments, characterised by hardground and hiatuses.

Sedimentary facies and foraminiferal assemblages of sediments sampled into seven Posidonia oceanica meadows from Western Mediterranean Sea were investigated. Six sampling sites are localised in Italy (Maratea, Ponza Island, Santa Marinella, Giglio Island, Osalla and Alghero), and one in France (Argentella, Crovani Bay, Corsica). The role of P. oceanica meadows in the sedimentary processes was investigated in different contexts: sampled meadows are set up both on soft and hard substrates, often forming “mattes”, in geographical areas subject to different wind and sea conditions (waves and longshore currents) and characterised by various coastal landforms and terrigenous inputs derived from costal erosional processes and/or fluvial contributions. A sedimentological, compositional, micropaleontological and geochemical characterisation of 111 bottom sediment samples, collected by SCUBA diving between 0 and 35 mwd, was carried out and finally tested with a Q-mode cluster analysis. Five sedimentary facies have been recognised, from terrigenous to mixed siliciclastic-carbonate and carbonate. Facies (and subfacies) are distinguishable by sorting, gravel content, abundance and maturity of clastic sediments, and weighted average of carbonate content. In all facies, foraminifers and red algae dominate the bioclastic fraction, whereas other bioclastic components are very subordinate and show a variable distribution. In all the investigated sites, benthic foraminiferal assemblages are generally dominated by typical epiphytic species, such as Asterigerinata mamilla, Lobatula lobatula, Peneroplis pertusus, Planorbulina mediterranensis, Rosalina spp. and miliolids. Nevertheless, these assemblages show some differences in the different sites according to the presence or absence of terrigenous contributions and, consequently, to the water turbidity. This parameter influences symbiont-bearing foraminifer as P. pertusus. Moreover, the samples from Argentella (Crovany Bay) are characterised by a peculiar assemblage, in which Miniacina miniacea dominates with very high frequencies.

The present study shows the preliminary micropaleontological results carried out on grab and box corer samples collected during the Eurofleet marine geological survey in the Terceira offshore (Azores Archipelago, Portugal) occurred in September 2011. A main WNW-ESE oriented fissural eruptive zone crosses the Terceira Island extending down to the sea, along the Serreta Ridge. An intermediate-depth submarine eruption occurred in 1998-2001 producing a consistent amount of volcanic materials scattered around the vent. Benthic foraminiferal assemblages were studied in order to obtain an ecological characterization of sea-floor and water masses in natural stressed environments like volcanic area of the Azores Islands, after the last volcanic eruption. The samples collected in a bathymetrical interval ranging between 260 and 410 m water depth, are constituted of blackish, sand-sized glass shards, in which highly vesicular to scoriaceous clasts prevail on fluidal striated fragments. All samples were stained with Rose Bengal to distinguish living and dead assemblages. Diversity index (?-Fisher index), Faunal density and Foraminiferal Abnormality Index (FAI) were calculated to define the structure of the assemblage and the degree of environmental stress. The preliminary results show that the living taxa number ranges from 18 to 43 while the ?-Fisher index shows constant values around 15-16. The living benthic assemblage is dominated by deep infaunal species like Angulogerina angulosa, and Bolivina spp. Angulogerina angulosa is considered in some cases epifaunal and in other ones infaunal species. In this study, the record of living specimens of A. angulosa along the whole box-corer, almost until 10 cm depth, suggests a certain capability of this taxon to migrate into the bottom sediments. Subordinately, epifaunal (Lenticulina spp., Eherenbergina bradyi, Stomatorbina concentrica, Quinqueloculina seminulum) and agglutinated (Aplophragmoides canariensis, Ammoglobigerina globigeriniformis, Spiroplectinella wrightii, Textularia spp., Eggerelloides scabrus) species are recorded too. Significant frequencies of specimens, showing signs of decalcification of the tests, were found. Similar test alterations, due to hydrothermal fluids, were recorded in foraminiferal specimens coming from other volcanic bottoms (Aeolian Arc, Tyrrhenian Sea).The dominance of living and dead A. angulosa specimens allows to consider this species as opportunistic pioneer taxon able to colonize stressed environments. In fact, the highest values of FAI (>2), recorded in the most samples, indicate a persisting environmental stress due to the occurrence of repeated volcanic events. Angulogerina angulosa and Bolivina spp. are the species showing more abundant deformed specimens. The test abnormalities consist mainly of irregular development of chambers and aberrant tests.

The marine sector between Piombino-Elba Island to the north and Argentario-Giglio Island to the south is dominated by the Ombrone River delta. Such river has a considerable load discharge in comparison to the limited drainage basin area and is responsible for the natural processes of transport and coastal evolution of the entire basin. Its fine sediments are dispersed along a wide area between the Elba Island and the Argentario Promontory. During the last low-stand, the continental shelf was largely exposed and the Ombrone River flowed into the Tyrrhenian Sea several kilometres to the west of the present mouth (Carboni et al., 2005). The Holocene evolution of the Ombrone delta was characterised by flooding of the coastal plain during the rapid sea-level rise, thus giving rise to brackish marshes or lagoons. Sea-level rise was punctuated by minor still stands, during which the river was able to build fluviodeltaic bodies into the paleovalley (Bellotti et al., 2004). At the end of postglacial sea-level rise (about 6000 yr BP), the Ombrone River flowed in a large lagoon, partly closed by prograding barrier-beaches (Bellotti et al., 2004). Sediment deposits referable to Etruscanearly Middle Ages (2800 to 700 yr BP), are considerable, as fluvial supplies were very high during cool-humid periods. At 700 yr BP, sedimentation values were low because of anthropic impact on this area (Bellotti et al., 2004). From 500 to 200 years BP, a new phase of high sedimentation rate started, related to a cool-humid climatic oscillation kwon as the Little Ice Age (LIA) coinciding with the maximum progradation of the delta. Successively an erosive phase affected the delta area caused by a decrease in solid supply, related to human actions (dams, wetland reclamations) or to a rainfall decrease. The submarine portion of the Ombrone River delta can be subdivided into delta front and prodelta slope. The prodelta slope develops between 20 m and about 90-100 mwd. Single-channel, very high resolution seismic profiles show three distinct seismic units (A, B and C), overlying the LGM unconformity, and formed during the last sea-level rise and highstand. The most recent unit (unit A) has a distinct seismic facies characterised by highamplitude and high-continuity reflectors generally affected by soft-sediment deformation (creep). This unit formed during the highstand phase and covers almost all the shelf area, exceeding 46 m in thickness off the Ombrone River mouth. It can be subdivided into several sub-units (at least six) possibly related to distinct phases of delta construction. Unit B lies above unit C and is characterised by a transparent seismic facies. It is distributed over the shelf with thickness of about 10-14 m and possibly formed during the late transgression-early highstand, before the construction of the wave-dominated delta. In this study we discuss temporal and spatial distribution patterns of the benthic foraminifera collected in cores comprising sediments of Holocene age. The specific aim of this paper is to document the paleoenvironmental changes in the Ombrone River delta area, by comparison with appropriate modern analogues. In this area, recent benthic foraminiferal assemblages have been extensively studied and a bathymetrical zonation parallel to the coast was defined (Frezza and Carboni, 2009). The quantitative and qualitative changes in foraminiferal assemblages reflect the impact of factors as organic matter and oxygen content, sediment type, and presence of seagrass. Seven cores collected in 1996 on the delta front (11-25.1 mwd) and on the outer continental shelf (76.4-105 mwd), were considered in this study. The cores mainly sampled sediment of unit A. The upper part of unit B was found only in one case. Two radiocarbon dates from core NK2 and one from NK3 were performed at the CEDAD (University of Salento, Italy). The analyses were carried out on benthic foraminifera at the bottom (sample NB1) and at -32.5 cm (sample NB16) of the core NK2, and at -136.5 cm (sample NC14) of the core NK3. All the results showed Late Holocene ages: NB1: 2815±100 cal yr BP; NB16: 302±45 yr BP; NC14: 656±93 cal yr BP. The micropaleontological analysis was carried out on a total of 96 samples. The Q-mode Hierarchical Cluster Analysis (HCA) was applied to the results of quantitative analysis. The samples of the 4 cores from the delta front were considered into a single statistical analysis, whereas the 3 cores from the prodelta slope-continental shelf were analysed separately. On the whole, seven clusters were recognised by the HCA. Each cluster is characterised by rather homogeneous foraminiferal content, which may be considered as corresponding to a distinct environment, ranging from infralittoral to lower circalittoral zones. Ammonia parkinsoniana assemblage (20.3-55.4%) was found in 6 samples from the NK7 core and indicates an infralittoral environment characterised by fresh-water input. Ammonia tepida, Elphidium decipiens and Elphidium granosum assemblage was found in 23 samples from the cores NK7, NK8, BOK5, and BOK10. This is a typical infralittoral assemblage characterised by taxa normally found in shallow-marine deposits near fluvial deltas, and it is comparable to the modern Ammonia spp. and Elphidium spp. assemblage (Frezza and Carboni, 2009). Bolivina catanensis assemblage (9.3-16.7%) was found in six samples from core NK8 and it is characterised by a dominance of Bolivina spp. (17.3-29.7%), that could be representative of relatively prolonged periods of dysoxia at the sea bottom. In the recent sediments of this area Bolivina spp. assemblages are not present. However, core NK8 was collected very close to the Ombrone mouth, whereas no recent samples studied by Frezza and Carboni (2009) were located in the same area. Valvulineria bradyana "high dominance" assemblage, comprising 10 samples from core NK4, is dominated by V. bradyana with very high percentages (56.2-72.4%), denoting stressed environmental conditions, related to very elevated input of organic matter by the Ombrone River. This foraminifer shows an opportunistic behaviour in organic matter enriched sediments, and it dominates assemblages corresponding to a transition between infralittoral and upper circalittoral environment, in the Mediterranean areas characterised by the presence of river mouths. Valvulineria bradyana "low dominance" assemblage consists of 10 samples from core NK2, 9 from core NK4, and 4 from core BOK10. Valvulineria bradyana is the dominant species, but with percentages lower than 50% (11-49%). The structure of this assemblage (as regards the percentages of dominance) allows comparison with the modern association found in the recent sediments (Frezza et al., 2005; Frezza and Carboni, 2009). Bulimina marginata and Melonis spp. assemblage includes 7 samples from core NK2 and 9 from NK3. These species are characteristic of circalittoral muds with high organic matter, but Melonis spp. does not seem to tolerate strong ecological stress. This assemblage is comparable to B. marginata assemblage present in recent sediments of the lower circalittoral zone (Frezza and Carboni, 2009). The circalittoral assemblage Uvigerina spp. and Bigenerina nodosaria is characteristic of 12 samples from the core NK3. Uvigerina spp. comprise two species (U. peregrina and U. mediterranea) recorded from the circalittoral zone and very abundant in bathyal muds, as well as B. nodosaria. On the whole, this association shows a high similarity with the circalittoral U. mediterranea assemblage, today present in front of the Ombrone River delta, at water depths exceeding 100 m (Frezza and Carboni, 2009).

In September 2011 a marine geological survey, the FAIVI (Features of Acores and Italian Volcanic Islands) cruise, was carried offshore the Terceira Island aboard the French R/V L'Atalante, in the framework of the Eurofleet program. One of the targets of the FAIVI cruise was the study of the Terceira volcanic edifice, particularly the area offshore the NW sector of the island (Serreta Ridge). Here an intermediate-depth submarine eruption occurred in 1998-2001, producing a consistent amount of lava balloons, i.e. balloon-like structures consisting of a thin lava shell surrounding a closed hollow interior, normally corresponding to a single large vesicle, or a few large convoluted vesicles, floating on the sea (Gaspar et al., 2003; Kueppers et al., 2012). Lava balloons are fairly unusual products of submarine eruptions. To date, balloon-like products have only been documented at Pantelleria, Italy in 1891 (Riccò, 1982; Washington, 1909), Mauna Loa, Hawaii in 1877 (Moore et al., 1985); Socorro Island, Mexico in 1993 (Siebe et al., 1995); at the 1998-2001 Serreta eruption offshore Terceira island (Azores) (Gaspar & Wallenstein, 1999) and, very recently offshore El Hierro, Canary Islands in October 2011 (Troll et al., 2012). Their genesis, in the framework of shallow-intermediate-depth submarine eruptions, is still poorly understood although several efforts have been made to improve the knowledge of the mechanisms producing such basaltic floating scorias (Kueppers et al., 2012). In order to reconstruct the style of eruption producing lava balloons and associated volcaniclastic deposits at Serreta, the investigations focused on: i) the identification and characterization of the emission vent(s) associated to the 1998-2001 submarine eruption; ii) the characterization of related deposits dispersal and grain size and, iii) the quantification of physical parameters of the eruptive event from the characteristics of sampled products (e.g., volatile contents, cooling rate). Here, we present preliminary results of the FAIVI cruise and attempt a first comparison with the 1891 eruption at Pantelleria, object of recent marine geological studies (Conte et al., submitted). As a first result, the FAIVI survey allowed to reconstruct with unprecedented detail the bathymetry offshore Terceira Island and, particularly, in the Serreta Ridge area. The latter is characterized by several volcanic features such as linear eruptive centres, volcanic cones and lava flows. Furthermore, bathymetric backscatter data and seafloor samples (collected through rock- and gravity- coring, grabbing and dredging) were preliminary analyzed on board and gave the following results: 1) The main vent of 1998-2001 Serreta eruption was identified; it is a half-cone, some 150 m high with a diameter of 700 m, resting on the top of the Serreta Ridge at 250-300 m water depth. 2) Most samples collected in the area surrounding the vent have been interpreted as related to the 1998-2001 Serreta eruption. They include, in fact, a large amount of fresh, highly vesciculated basaltic scoria, with the typical layered vescicularity observed in the lava balloon crust recovered intact during the 1998-2001 eruption. Material sampled from the top of Serreta Ridge encompasses different types, from large scoriaceous blocks (up to 60 cm length) of black fresh basalt characterized by numerous, large, highly convoluted vesicles with smooth internal walls, to fragments of scoriaceous material with dimensions