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

Mesophotic reefs are found in water depths greater than 30m and as such are, for the most part, removed from most direct wave activity, notably in the Mediterranean Sea. There, they are protected from anthropogenic impact and serve as a possible refuge for marine biodiversity in a warming ocean. Yet, like any reef, their growth is modulated by the distribution of the sediment they produce and supply of nutrients. Here we explore the mechanisms governing the sediment distribution around a coralligenous mesophotic reef system as a case study of the long-term governing mechanisms in this environment. A detailed survey of a mesophotic reef offshore Israel was carried out using acoustic imaging from an autonomous underwater vehicle. This survey generated a highly detailed (cm-scale) resolution dataset with wide area coverage of the sediment distribution patterns around the reef. The mesophotic reefs are built as a series of asymmetric ridges with biogenic sediment filling the depressions between them. Two types of sediment bedforms were identified in the sediment fill - elongated linear bedforms aligned north-south; and intersecting smaller bedforms aligned NW-SE and NE-SW, forming chevron-like shapes. Both types of bedforms are composed of coarse-grained material (sand to gravel) and their distribution is partially related to their location relative to the hard substrate. The bedform present and the ridge asymmetry points to a prominent role of a south-to-north bottom current. These current supplies nutrients to the reefs, but also loads sediment on their southern side, leading to asymmetry. Additionally, the chevron bedforms are attributed to interactions with the rocky substrate and internal waves. These internal waves likely also play a role in modulating the reefs’ growth. The geometries and growth of mesophotic reefs, and the distribution of the sediment around them, are controlled by the combination of both internal waves and bottom currents.

In this study we revisited the Cretaceous of the Eratosthenes Seamount (ESM) from IODP LEG 160 Hole 967E, updating the chronology, depositional environment, and paleobathymetry of the ESM. Our goal was also to address the spatio-temporal distribution of organic matter and, by comparison with the eastern margins of the Levant Basin, discuss basin-wide controls on its deposition and preservation. The investigated core has a relatively continuous Cretaceous succession from the Aptian to the Danian. By identifying the Pα Zone we conclude that the base of the Paleocene is included in the 967E section. A total of 17 ages were identified, with low sedimentation rates of 0.04– 2.37 cm/kyr. Petrographic analysis revealed pronounced differences, from micritic pellets, benthic foraminifera, algae, and mollusks in the bottom part of the core, to deep water facies in the uppermost Cretaceous. Paleobathymetry ranged between 0.5 and 5 m in the Aptian to 300–600 m in the Maastrichtian. Both high productivity and OMZ conditions prevailed during the Cenomanian–Turonian, as well as elsewhere in the eastern Mediterranean. While the low core recovery might affect reliable interpretation, we present two alternative explanations for the high vs. low organic content of the Campanian–Maastrichtian in the eastern Levant Basin vs. the ESM: (1) Location relative to upwelling cells; (2) Relative bathymetry, with the ESM representing a paleohigh for much of the Cretaceous, similar to the organic-poor anticline deposits in the eastern Levant, where the massive intervals of organic-rich carbonates accumulated only in the synclines of the Syrian Arc deformational belt.

Highlights • Multilevel Composition is an innovative method involving color composition and co-rendering of multilevel attribute maps. • It is useful for characterizing multi-depth geological features based on their spatiotemporal distribution within three-dimensional seismic data. • The technique produces a single image map, in which inter-window/layer depth information is coded in colors for reliable representation of the actual geology. • In the eastern Nile fan, it was applied to visualize and resolve the complexities of buried clastic deep-water depositional elements. • On the Omakere Ridge, it successfully illuminated seafloor seeps and reveals their link to deeper fluid-bearing intervals. Abstract Advanced seismic data and multi-attribute visualization techniques, such as color blending of attributes, have considerably enhanced the capability of interpreters to characterize geological features in three-dimensional (3D) seismic reflection datasets. However, high resolution investigation of complex, vertically linked geological features such as channel systems and fluid conduits, remains challenging. These features may appear in the dataset as pronounced attribute anomalies, such as high-amplitude or spectrally or structurally enhanced seismic reflectivity bands, at several depth levels. Vertical linkages between these features, however, may not be readily established. We have developed an innovative method, Multilevel Composition, for an intuitive display of vertically connected features. Our method involves the composition of attribute maps from three different depth/time windows or slices onto a single map, in which inter-window/layer depth information is coded in colors. Multilevel Composition starts with the identification of suitable seismic attributes, such as high amplitudes in the examples displayed here, to map features of geological interest. At least one reference horizon is then identified and mapped in the vicinity of the target window of interest. Three sub-windows are then defined with respect to the reference horizon(s) based on the vertical and spatial distribution of the geological features. Relevant seismic attributes are computed for each of the sub-windows, and the resulting maps, one from each sub-window, are assigned basic color channels and are co-rendered to reveal multilevel linkages between these features. We demonstrate the efficacy of this method by applying it to two 3D seismic datasets, one illuminating deep-water depositional elements in the eastern Nile fan, eastern Mediterranean and the other targeting seafloor seeps and underlying gas migration systems beneath the Omakere Ridge, offshore New Zealand. The new method is simple and should be easy to implement to enhance seismic interpretation workflows.

Polygonal, layer-bound normal faults can extend over very large areas (>2,000,000 km2) of sedimentary basins. Best developed in very fine-grained rocks, these faults are thought to form during early burial in response to a range of diagenetic processes, including compaction and water expulsion. Local deviations from this idealised polygonal pattern are common; however, basin-scale, layer-bound faults with non-polygonal map-view are not well-documented and accordingly, their genesis is not well-understood. In this study we use 3D seismic reflection data, biostratigraphy, and well-logs from the Southern Levant Basin, offshore Israel, to develop an age-constrained seismic-stratigraphic framework and determine the geometry and kinematics of such basin-scale fault system. The faults tip-out downwards along an Eocene Unconformity, but unlike layer-bound faults in the Northern Levant Basin, they do not reach the base of the Messinian evaporites, instead tipping-out upwards at the top Langhian. On average, the faults in the Southern Levant Basin are 6.3 km long, have an average throw of 120 m, and consistently strike NW-SE. Throw-depth plots, accompanied by thickness changes, indicate the faults nucleated as syn-depositional faults in a mudstone-dominated unit, and are spatially and kinematically associated with a WSW-ESE-striking strike-slip fault. Unlike true polygonal faults, these faults propagated through ~2 km-thick sandstone-dominated Oligocene-Miocene strata. Whereas previous studies from the Northern Levant Basin associate fault nucleation and growth with burial-related diagenesis, the sandstone-dominated character of the Oligocene-Miocene suggests that this process cannot be readily applied to the Southern Levant Basin. Instead, we highlight potential tectonic events that occurred during and may have triggered thin-skinned extension at times of fault growth. Layer-bound normal faults therefore should be considered in the geodynamic and structural context of the basin in which they formed.

The continental shelf of Israel experienced major geomorphological changes during the past 250,000 years as a consequence of global sea level changes and oscillating sedimentation patterns of the Nile River. This study aims to provide insights into the geomorphological evolution of the Israeli continental shelf through time in relation to sea level oscillations. This research is based on geophysical interpretation of high resolution seismic surveys acquired along the Israeli continental shelf, complemented by statistical analysis of the interpretation picks. The main task included the identification of unconformities, erosional truncations and similar surfaces in the seismic profiles; and their chronological assemblage according to their stratigraphic order and ages obtained by previous studies. Seismic stratigraphy analysis of the geophysical dataset allowed dividing the shelf into four main seismic units (SU1 to SU4) bounded by distinctive four horizons. Two units (SU1 and SU3) represent transgression periods, probably during Marine Isotope Stages MIS1 and MIS5; and the two other units (SU2 and SU4) show morphologies suggesting marine regressive conditions, probably during MIS2 and MIS6. Overall the seismic units represent two major sedimentary cycles, which occurred presumably since MIS7 (ages according to previous studies) and correlate with the Hefer Formation stratigraphy (Tel Aviv and Ashdod members). Moreover, high resolution seismic interpretation reveals a distinctive morphology of some of the bounding surfaces in the form of depth-controlled terraces. Geomorphological and statistical analyses of these features, and their correlation with past sea level curves, suggest that their genesis is related to paleo-shoreline environments that probably occurred during MIS2 and MIS6. Particularly, the presumed MIS6 terrace serves as a prominent regional marker that was further used for estimating the average subsidence rates of the Israeli continental shelf to 0.18 mm/y since 136,000 ka. This study suggests the utilization of a novel statistical approach to unravel the mechanisms controlling the geomorphological evolution of the Israeli continental shelf, which can be applied to other shelf environments worldwide.

Authigenic seep carbonates, which are found globally at continental margins, can serve to characterise the seepage of hydrocarbon-enriched fluids into the oceans. This study aims to identify past seepage activity and gas migration pathways on the south-eastern margin of the Mediterranean, based on the analysis of authigenic seep carbonates collected during the 2016 EUROFLEETS 2 SEMSEEP expedition aboard the RV AEGEO. Seep carbonates with three different morphologies (chimneys, crusts and pavements), are studied using standard sediment petrography (fluorescence, CL and standard optical microscopy), as well as X-ray diffraction, Raman spectroscopy and stable isotope analyses. Recurrent cement and replacement phases identified contain different amounts of aragonite, low-magnesium calcite (LMC), high-magnesium calcite (HMC) and dolomite. Carbonate chimneys consist of micrite (δ13CVPDB of -10 to +5 ‰) with dispersed barite and dolomite crystals and fan-shaped aragonite (δ13CVPDB of -52 to -30 ‰). Locally, aragonite fans are replaced by LMC spherulites and blocky HMC. Botryoidal LMC cements are forming in small cavities. Carbonate crusts consist mainly of micrite rich in fossils and detrital grains with LMC breccias, HMC nodules (δ13CVPDB of -35 to -20 ‰) and cements and fan-shaped aragonite cement. These are partly replaced by LMC microsparite and show several growth stages. Carbonate pavements consist mainly of micritic dolomite and HMC. LMC microsparite can be identified as well. Fan-shaped aragonites are locally present as pore-lining cement. Fe-oxides are coating the low- and high-Mg calcitic and dolomitic cements. Raman spectroscopic analyses confirm the presence of aragonite, dolomite and specific organic compounds associated to different crystals.Sediment petrography, XRD and stable isotope analysis reveal several phases of methane seepage through time. Distinct mineralogies (dolomite and aragonite) within the seep carbonate morphologies, result from different formation mechanisms (anaerobic oxidation of methane during aragonite formation and predominately sulphate reduction during dolomite formation). Raman spectroscopy highlights the presence of organic compounds within specific carbonate phases, which might play an important role in the carbonate formation.

Nile derived siliciclastic sediments are the main source for sedimentation along the Levant continental margins. The sediments are transported along the southeastern Mediterranean coast via jet and longshore currents, mainly operating along the shelf. However, the cross shelf component of sediments transport, responsible for conveying sediments towards the upper slope, is less known. To better understand the cross-shelf vs. the longshore components of sediment transport, we studied two ~5.5 m piston cores: DOR280 and DOR350, sampled on the upper continental slope at 280 m and 350 m water depth, respectively.We analyzed the particle size distribution (PSD) as well as the benthic-foraminiferal assemblages and their shells taphonomy, for documenting both the source and the transport mechanism of the upper continental-slope sediments. The radiocarbon sediment age at the DOR280 core-base is ~660 ±70 Cal Yrs. B.P., indicating an exceptionally high average sedimentation rate of ~800 cm/kyr. DOR280 consists of alternating two sedimentary facies: (1) Laminated (L) intervals with bimodal PSD and high ratio of allochthonous vs. autochthonous (allo/auto) foraminiferal species, characterized by a high percentage of benthic-foraminiferal broken and poorly preserved shells, indicating contribution of transported sediments originating from mid-shelf habitats. (2) Non-laminated (NL) intervals with unimodal PSD, low allo/auto ratio (in-situ deposition. The L intervals are interpreted as sediment laden gravity currents, possibly turbidites. Numerous centimeters-thick turbiditic events were identified, based on grain-size grading and discontinuous eroded lower stratigraphic-contacts. Sedimentation rate calculated only for the NL intervals is still exceptionally high, excluding hemipelagic sedimentation as the sole deposition. Thus, a contour bottom-current transported component is suggested for the NL sediments of DOR280 (i.e. contourites). DOR350 reveals higher sedimentation rates (age of ~350 ±80 Cal Yrs. B.P. at the core-base) and consists mostly of the L facies. Hence, the sediments of DOR350 are mostly consist of transported (by turbidities) sediments with only minor contribution of hemipelagic sedimentation or contourites.We conclude that a hybrid contourite-turbidite system actively prevails along the Levant upper continental slope offshore Israel, apparently at water depth of less than 350 m.

Advanced seismic data and multi-attribute visualization techniques such as the red-green-blue (RGB) have considerably augmented the capability of interpreters to characterize geological features on three-dimensional (3D) seismic reflection datasets. However, high resolution investigation of complex features remains challenging, requiring additional approaches to improve all round interpreters’ performance. Intervals of interest are commonly associated with intricate geological features, including channel systems and fluid migration pathways, which may be concealed in the dataset as multilevel high-amplitude seismic reflectivity bands. Delineating such features onto a single, intuitive map is often an arduous task. This may prove even more demanding where such features are spatially connected and occur near discontinuous and difficult-to-interpret horizons. To aid this task, we have developed an innovative technique involving RGB-blending and composition of multilevel amplitude maps, multilevel composition. Multilevel composition involves identification of high-amplitude features of geological interest within the dataset and defining their window of occurrence . This is followed by the interpretation of at least one reflecting horizon within/around the target window and the division of the window into three sub-windows based on the spatiotemporal distribution of the geological features. Amplitude-accentuating seismic attributes are computed for the sub-windows, the resulting maps are assigned to red (shallowest level), green (intermediate level) and blue (deepest level) colors and are co-rendered in the RGB color space. This results in a single map in which inter-window/layer depth information is coded in colors for reliable representation of the actual geology . We demonstrate the efficacy of this technique by applying it to characterize classic deep-water depositional elements in the eastern Nile fan, eastern Mediterranean, and to investigate seafloor seeps and underlying fluid plumbing systems beneath the Omakere Ridge, offshore New Zealand, using high-resolution 3D seismic data. The new technique is simple and easy to execute and enhances existing seismic interpretation workflows.

Several oil shows have been reported from offshore and onshore wells of the Levant Basin, which promoted research and exploration as indicators for potential economic discoveries in the yet unpenetrated Mesozoic interval of the basin. In most cases, no definitive source to oil correlation has been established, advocating the need for the fingerprinting of regional source rocks to compare their organic geochemical signatures to those of oils. A summary of known properties of oils sampled from different wells in the region raised several questions regarding source–oil and oil–oil correlation, maturity, and source of the organic matter. In this part of the project we examined the Cretaceous section in the region by conducting a sedimentological and organic geochemical investigation of organic-rich intervals from ODP well material and onshore wells in the Levant region. We show that organic-rich Upper Cretaceous deposits, Turonian OAE2, and lowermost Cretaceous Barremian organic-rich deposits, should be considered as viable candidates for sourcing hydrocarbon formation in the deep basin, where they might have matured.

Jellyfish locomotion and orientation have been studied in the past both in the laboratory, testing mostly small jellyfish, and in the field, where it was impossible to control the seawater currents. Utilizing an outdoor water flume, we tested the locomotion of jellyfish when swimming against and with currents of up to 4.5 cm s−1. We used adult jellyfish from two of the most abundant species in the eastern Mediterranean, Rhopilema nomadica and Rhizostoma pulmo, and measured their pulsation frequency and swimming speed relative to the water. While pulsation frequency was not affected by the water velocity, jellyfish swam faster against the current than with it. This finding suggests that jellyfish possess a sensory ability, whose mechanism is currently unknown, enabling them to gauge the flow and react to it, possibly in order to reduce the risk of stranding.

[The southeastern mediterranean continental slope bathymetry is impacted by interleaved imprints of mass transport processes. These are delineated, classified and mapped through semi‐automatic bathymetric spectral decomposition, appraising their role in sediments bypassing and maintenance of a long‐term shelf‐to‐basin equilibrium profile. , Abstract Understanding continental‐slope morphological evolution is essential for predicting basin deposition. However, separating the imprints and chronology of different seafloor shaping processes is difficult. This study explores the utility of bathymetric spectral decomposition for separating and characterizing the variety of interleaved seafloor imprints of mass wasting, and clarifying their role in the morphological evolution of the southeastern Mediterranean Sea passive‐margin slope. Bathymetric spectral decomposition, integrated with interpretation of seismic profiles, highlights the long‐term shape of the slope and separates the observed mass transport elements into several genetic groups: (1) a series of ~25 km wide, now‐buried slide scars and lobes; (2) slope‐parallel bathymetric scarps representing shallow faults; (3) slope‐perpendicular, open slope slide scars; (4) bathymetric roughness representing debris lobes; (5) slope‐confined gullies. Our results provide a multi‐scale view of the interplay between sediment transport, mass transport and shallow faulting in the evolution of the slope morphology. The base of the slope and focused disturbances are controlled by ~1 km deep salt retreat, and mimic the Messinian base of slope. The top of the open‐slope is delimited by faults, accommodating internal collapse of the margin. The now‐buried slides were slope‐confined and presumably cohesive, and mostly nucleated along the upper‐slope faults. Sediment accumulations, infilling the now‐buried scars, generated more recent open‐slope slides. These latter slides transported ~10 km3 of sediments, depositing a significant fraction (~3 m in average) of the sediments along the base of the studied slope during the past < 50 ka. South to north decrease in the volume of the open‐slope slides highlight their role in counterbalancing the northwards diminishing sediment supply and helping to maintain a long‐term steady‐state bathymetric profile. The latest phase slope‐confined gullies were presumably created by channelling of bottom currents into slide‐scar depressions, possibly establishing incipient canyon headword erosion.]

Our study comprises a high-resolution multi-proxy investigation of a ~6 m long piston core DOR280, sampled from the headscarp of a mapped landslide on the upper continental slope (280 m water depth) at the Dor Disturbance area, northern central Israel. The core retrieved the sediment sequence overlaying the sliding plane of the last major landsliding event. Benthic foraminiferal assemblages and taphonomy, alongside particle size distribution, were used to determine the provenance, transport distance, and reoccurrence time of mass transport events in this area. Radiocarbon ages were measured along the core revealed an age of ~600 Cal Yrs. B.P. for the core base, suggesting unexpectedly high average sedimentation rate of ~10 m/kyr, which is highest at the core top meter. Computed Tomography (CT) of DOR280 shows two alternating sedimentary facies: 5 – 208 cm thick Non-Laminated (NL) and 5 – 37 cm thick Laminated (L). The L-facies sequences also include 0 – 4 cm thick High-Density Laminas (HDL). The NL-facies intervals consist of unimodal fine-sediments dominated by clay minerals. Their foraminiferal assemblage is dominated by autochthonous species (e.g. Uvigerina spp.) and low percentage of broken shells. This indicates that the NL-facies represents mostly in-situ hemipelagic deposition. The L-facies intervals also record unimodal size-distribution of fine-sediments dominated by clay minerals, but their foraminiferal assemblages are dominated by allochthonous species (e.g. Ammonia spp.) and high percentage of broken shells, indicating a contribution of transported sediments, originated from mid-shelf habitats. The HDL-facies consist of bimodal sediments comprised of fine silty-clay (~5 µm) and coarse silty components (~40 µm), dominated by quartz and calcite; as well as poorly preserved and broken shells of allochthonous foraminifera species. Thus, the HDL represent significant contribution of mid-shelf-origin sediments and are interpreted as turbidite-like mass transport events.The temporal distribution of the 27 HDL events is nonrandom, revealing clusters at 59 ± 14 (n=9), 134 ± 12 (n=8), 453 ± 21 (n=4) and 641 ± 10 (n=4) years before present. These findings show prevailing cross-shelf and down slope sediments transport in the Dor Disturbance area. The HDL events can be triggered by large remote earthquakes (> 6.5), tsunami, winter storms or by sediment load that coincided with high-stand Nilotic episodes. However, mechanisms controlling the observed recent mass transport in the Dor Disturbance area still need to be studied.DOR280 is the first piston core studied in high resolution at the upper continental slope of of the Isreali offshore. The use of benthic foraminifera assemblages and their shells taphonomy reveals the transported sediments within the core and enables an assessment regarding their source. The findings reported here identified much higher sediments accumulation rate than previously known and thus have implications to the evaluation and mitigation of marine geo-hazard in the studied area.

The Eastern Mediterranean continental slope offshore Israel became a focus of exploration for, and production of, natural gas in recent years. The 2010–2011 Nautilus ROV expedition performed detailed video recordings and sampling in two areas offshore Israel: the Palmachim disturbance, southwest of Tel Aviv, and an area offshore Acre, north of Haifa. An analytical programme regarding the carbonate structures was carried out, examining the overall mineralogy, stable C and O isotopes, and Ca, Mg, and Mn concentrations. This provided information on their composition and as a result, an indication of the carbon sources and temperature of formation. The major authigenic minerals identified comprised magnesian calcite, dolomite, aragonite, and kutnohorite. The detrital minerals included quartz, clays, feldspars, and rare augite and enstatite, likely transported from the Nile estuary. The carbon isotope composition of aliquots taken from nineteen samples from these areas have an overall δ13C range from −62.0 to −0.1‰PDB, indicating a range of microbial/biogenic and thermogenic methane contributions. The range of δ18O from 2.7 to 7.0‰PDB reflects the range of temperatures of formation. The δ18O characteristics differ among areas. In general, high values; δ18O >5‰PDB are recorded from area N2 of the Palmachim disturbance, indicating low temperature of formation. Low values of δ18O (13C increase from −39.9 to −0.1‰(PDB), and δ18O decrease from 6.2 to 4.7‰(PDB). These values indicate a decrease in the methane-derived carbon contribution and an increase in temperature. Kutnohorite, Ca(Mn2+, Mg, Fe 2+)(CO3)2 is a major component in samples from Acre, and less so in the Palmachim disturbance. An exploratory investigation of the relationship between Mn/Ca, δ18O and δ13C revealed that samples having Mn/Ca < 0.1(wt./wt.) have δ13C 0.1 have δ13C between −35 and −22‰PDB suggesting a thermogenic origin. These results suggest that the mineralogical, isotopic δ13, δ18O, and chemical (Mn/Ca indicative of kutnohorite) characteristics of surficial carbonate structures can indicate and distinguish between deep and shallow methane sources in the Eastern Mediterranean.

In this paper we present a methodology and first results of seafloor compressional sound speed estimation in a compacting passive margin setting of the southeastern Mediterranean Sea, offshore Israel. The estimation was obtained through a coupled wide-angle reflection-refraction travel time analysis of standard commercial 2D multichannel seismic data, acquired with a 7.2km long horizontal receivers array, and geoacoustic inversion. We found that three parameters were needed to model the observed travel times: 1) the compressional sound speed at water-sediment interface c0; 2) a constant velocity gradient K within the sub-bottom sediments layer; and 3) the thickness of the relevant sub-bottom layer H2. The model considered consists of a water layer with a vertically varying sound speed profile according to the season. The thickness of this layer is constrained by the pre-known seafloor bathymetric depth of 1200 m. The base of the model is the top of a regional salt layer, which underlies the investigated sub-bottom layer and constrains H2. The estimated c0 and K are 1550 m s−1 and 0.7 s−1, respectively. The proposed method allows to estimate a relatively low (∼1500-1650 m s−1) sound speed at water-sediment interface, where it is challenging to use conventional refraction-based methods.

Seafloor video surveys were carried out with the ROV Max Rover in the Palmahim Disturbance (PD) area, offshore Israel, in September 2016 during the EUROFLEETS2 SEMSEEP cruise on board the R/V AEGAEO. Preliminary observations of distribution and frequencies of bivalve accumulations show that they are mostly composed by Lucinoma kazani shells. Valves are distributed mainly along the base of authigenic carbonate crusts, in association with bacterial mats and inside inactive chimney-like structures, sometimes associated with crabs and living tubeworms. However, no living molluscs were observed.The relation between distribution of bivalve beds and seepage activity is not straightforward in the PD area. However, the presence of these accumulations and the size of L. kazani, suggest that seepages may have lasted for at least one decade, before its reduction/cessation that induced L. kazani mortality. The presence of few articulated valves of this species indicates that they were alive up to one year before the ROV observations and their different preservation state may imply different seepage phases. This research shows that chemosymbiotic benthic communities may be used as a proxy for better understanding the past dynamics of fluid emissions at the seafloor. However, further quantitative studies are needed to confirm these observations.

The Messinian salinity crisis (MSC) is perceived as an environmental crisis governed by climatic and tectonic controls, affecting global oceans' salinity and shaping the Mediterranean Sea's biochemical composition. Recently drilled offshore wells in the Levant Basin retrieved a sedimentary record of the deep-basin Mediterranean MSC salt deposits and the underlying pre-evaporite unit. In this study, we have concentrated on the pre-evaporite interval and its transition into the overlying evaporites. Analysis of this data set changes the way these deposits have been perceived since the 1970s, when they were first penetrated in their uppermost part during Deep Sea Drilling Project expeditions. Using sedimentology, seismic interpretation, biostratigraphy, and astronomical tuning, we show that Messinian salt deposition in the Eastern Mediterranean began during stage 1 of the MSC. In contrast to the present paradigm, salt was deposited synchronously with gypsum in the marginal and intermediate-depth basins significantly before the 50 k.y. interval coined as the "MSC acme event", ~400 k.y. after the crisis began. Thus salt precipitation took place in a non-desiccated deep basin, having a restricted but often open connection with the Atlantic Ocean, substantially altering our understanding of the mechanisms governing the deposition of salt giants. A coeval onset of basinal halite and marginal gypsum precipitation calls for a revaluation of global-scale climatic and oceanographic models of the MSC, taking into account a much older age for the beginning of halite deposition.

Maritime connectivity between Cyprus and other Eastern Mediterranean coastal regions on the mainland constitutes a critical factor towards understanding the origins of the early visitors to Cyprus during the onset of the Holocene (circa 12,000 years before present) in connection with the spread of the Neolithic in the region (Dawson, 2014). In this work, ocean circulation modeling and particle tracking are employed for characterizing drift-induced sea-borne connectivity for that period, using data and assumptions to approximate prevailing paleo-geographical conditions (re-constructed coastline from global sea level curves), and rudimentary vessel (rafts, dugouts) characteristics, as well as present-day weather conditions. The Regional Ocean Modeling System (ROMS, Shchepetkin and mcWilliams, 2005), forced by Copernicus Marine portal hydrological data, with wave and wind forcing derived from a combination of global reanalysis data and regional-scale numerical weather predictions (ERA5 and E-WAVE project products), are employed to provide the physical domain and atmospheric conditions. Particle-tracking is carried out using the OpenDrift model (Dagestad et al., 2018) to simulate drift-induced (involuntary) sea-borne movement. The sensitivity of the results on the hydrodynamic response (e.g. drag) of rudimentary vessels, such as rafts of postulated shape, size, and weight, that are believed to have been used for maritime travel during the period of interest, is also investigated. The simulation results are used to estimate the degree of maritime connectivity, due to drift-induced sea-borne movement, between segments of Cyprus coastline as well as its neighboring mainlands, and identify areas of both coastlines where landing/departure might be most favorable.This work aims to provide novel insights into the possible prehistoric maritime pathways between Cyprus and other Eastern Mediterranean coastal regions, and is carried out within the context of project SaRoCy (https://sarocy.cut.ac.cy), a two-year research project implemented under the “Excellence Hubs” Programme (contract number EXCELLENCE/0198/0143) of the RESTART 2016-2020 Programmes for Research, Technological Development and Innovation administered by the Research and Innovation Foundation of Cyprus.ReferencesDagestad K.-F., Röhrs J., Breivik Ø., Aadlandsvik B. 2018. “OpenDrift: A generic framework for trajectory modeling'', Geoscientific Model Development 11, 1405-1420. https://doi.org/10.5194/gmd-11-1405-2018.Dawson, H. 2014. Mediterranean Voyages: The Archaeology of Island Colonisation and Abandonment. Publications of the Institute of Archaeology, University College London. Walnut Creek, California: Left Coast Press Inc.Shchepetkin, A. F., & McWilliams, J. C. 2005. “The regional oceanic modeling system (ROMS): A split-explicit, free-surface, topography-following-coordinate oceanic model”. Ocean Modelling 9, no. 4, 347-404. https://doi:10.1016/j.ocemod.2004.08.002.

Chemosymbiotic micro- and macro-fauna related to cold-seep sites were recovered in the Palmahim Disturbance (PD), offshore Israel, during EU EUROFLEETS2 SEMSEEP Cruise, by box-coring and Remotely Operated Vehicle (ROV) dives. No live macrofauna was identified in the collected sediments, with the exception of the seep-related crustacean Calliax lobata (de Gaillande and Lagardère, 1966). Numerous Calliax claws testify the past colonization of these soft bottoms by several generations of this ghost shrimp. After sediment sieving on 1 mm, we identified gastropods belonging to the families Trochidae, Eucyclidae, unassigned Seguenzioidea (genus Anekes), Rissoidae, Elachisinidae, Raphitomidae, Mangeliidae, Architectonicidae, Orbitestellidae, and Acteonidae. The identified bivalves belong to the families Nuculidae, Yoldiidae, Mytilidae, Lucinidae, Thyasiridae, Semelidae, Kelliellidae, Vesicomyidae, Xylophagidae, and Cuspidariidae. A seep-related group of chemosymbiotic molluscs was detected, including: Taranis moerchii (Malm, 1861), Lurifax vitreus Warén and Bouchet, 2001, Idas ghisottii Warén and Carrozza, 1990, Lucinoma kazani Salas and Woodside, 2002, Thyasira biplicata (Philippi, 1836), Isorropodon perplexum Sturany, 1896, and the newly described Vesicomyid species Waisiuconcha corsellii n. sp., that represents also the first record of the genus Waisiuconcha in recent Mediterranean sediments.The ROV dives recorded local patches of several m2 of seafloor covered by dead shells of L. kazani, with a density of up to about 200 loose shells per square meter. The potential occurrence of seep-related foraminifera, among low-oxygen tolerant species, was explored by comparison with previously sampled adjacent localities, and lead to the identification of Chilostomella oolina, Globobulimina affinis and G. pseudospinescens as potential foraminiferal seep indicators in the southeastern Mediterranean Sea. The absence of live, seep-related fauna in surface sediments in the PD, where seepage has been confirmed, suggests intermittent activity and a pause or decline of the investigated seeps.

Large national programs in the United States and several Asian countries have defined and characterised their marine methane hydrate occurrences in some detail, but European hydrate occurrence has received less attention. The European Union-funded project “Marine gas hydrate – an indigenous resource of natural gas for Europe” (MIGRATE) aimed to determine the European potential inventory of exploitable gas hydrate, to assess current technologies for their production, and to evaluate the associated risks. We present a synthesis of results from a MIGRATE working group that focused on the definition and assessment of hydrate in Europe. Our review includes the western and eastern margins of Greenland, the Barents Sea and onshore and offshore Svalbard, the Atlantic margin of Europe, extending south to the northwestern margin of Morocco, the Mediterranean Sea, the Sea of Marmara, and the western and southern margins of the Black Sea. We have not attempted to cover the high Arctic, the Russian, Ukrainian and Georgian sectors of the Black Sea, or overseas territories of European nations. Following a formalised process, we defined a range of indicators of hydrate presence based on geophysical, geochemical and geological data. Our study was framed by the constraint of the hydrate stability field in European seas. Direct hydrate indicators included sampling of hydrate; the presence of bottom simulating reflectors in seismic reflection profiles; gas seepage into the ocean; and chlorinity anomalies in sediment cores. Indirect indicators included geophysical survey evidence for seismic velocity and/or resistivity anomalies, seismic reflectivity anomalies or subsurface gas escape structures; various seabed features associated with gas escape, and the presence of an underlying conventional petroleum system. We used these indicators to develop a database of hydrate occurrence across Europe. We identified a series of regions where there is substantial evidence for hydrate occurrence (some areas offshore Greenland, offshore west Svalbard, the Barents Sea, the midNorwegian margin, the Gulf of Cadiz, parts of the eastern Mediterranean, the Sea of Marmara and the Black Sea) and regions where the evidence is more tenuous (other areas offshore Greenland and of the eastern Mediterranean, onshore Svalbard, offshore Ireland and offshore northwest Iberia). We provide an overview of the evidence for hydrate occurrence in each of these regions. We conclude that around Europe, areas with strong evidence for the presence of hydrate commonly coincide with conventional thermogenic hydrocarbon provinces., Sí

To estimate The potential inventory of natural gas hydrates in the Levant Basin we correlated the gas hydrate stability zone (GHSZ), modeled with locally estimated thermodynamic parameters, with seismic indicators of gas. Compilation of oceanographic measurements define the deep-water temperature and salinity to 13.8°C and 38.8‰ respectively, predicting the top GHSZ at a water depth of 1250±5 m. Assuming beneath the seafloor a hydrostatic pore-pressure, the water body salinity, and geothermal gradients ranging between 20 to 28.5°C/km, yields a useful first-order base-GHSZ approximation. Our model predicts that the entire northwestern half of the Levant Basin lies within the GHSZ, with a median thickness of ~150 m. High amplitude seismic reflectivity (HASR) imaged on an extensive 3D seismic dataset, consistently correlates with verified active seafloor gas seepage and is pervasively distributed across the deep-sea fan of the Nile within the Levant. Two main trends observed for the distribution of HASR are suggested to represent: (1) shallow gas and possibly hydrates, within buried channel-lobe systems 25 to 100 m beneath the seafloor; and (2) a regionally discontinuous bottom simulating reflection (BSR) broadly matching the modeled base GHSZ. We therefore estimate the potential methane hydrates reserve within the Levant Basin at ~4 Tcf.

Mass transport deposits (MTDs) are commonly regarded as motionless evidences of past mass wasting events. Three-dimensional seismic surveys acquired offshore central Israel reveal continued long-lasting and even current deformation of >1.5 Myr old MTDs, now buried hundreds of meters beneath and still impacting the seafloor. Faulting and folding of the Messinian-Pliocene unconformity (M), at the base of the studied interval, represent the possible impacts of tectonic and halokinematic deformation. However, an ~200 m thick continuous stratified unit straddles the M and entirely separates the overlaying Plio-Quaternary sedimentary stack from underlying faulting. Overlaying and etched into this stratified unit are headscarp regions of two up to 450 m thick buried MTDs, characterized by distinct combinations of chaotic seismic reflections and typically ~1 km wide detached and rotated blocks. “Crowns” of growth faults emanate upward from these MTD headwalls, truncating and deforming the overburden and offsetting overlaying reflections by tens of meters up to ~100 m below the seafloor. Moreover, asymmetric sagging and faulting of the overburden mimic the layout and flow pattern of the MTDs and rafted blocks within, providing kinematic indications of combined compaction and lateral flow. These observations imply that the MTDs undergo continuous postslumping differential compaction, combined with lateral mobilization. Additional smaller and younger buried MTDs distributed within the overburden are observed to portray similar deformation kinematics. We suggest that the buried MTDs provide deformational foci and pathways for downslope internal collapse of the continental margin at large, offering a new possible mechanism of thin-skinned extension.

Sea-level fluctuations are a dominant mechanism that control coastal environmental changes through time. This is especially the case for the successive regressions and transgressions over the last interglacial cycle, which have shaped the deposition, preservation and erosion patterns of unconsolidated sediments currently submerged on continental shelves. The current study focuses on creating an integrated marine and terrestrial geophysical and litho-stratigraphic framework of the coastal zone of Hadera, north-central Israel. This research presents a case study, investigating the changing sedimentological units in the study area. Analysis suggest these represent various coastal environments and were deposited during times of lower than present sea level and during the later stages of the Holocene transgression. A multi-disciplinary approach was applied by compiling existing elevation raster grids, bathymetric charts, one hundred lithological borehole data-sets, and a 110 km-long sub-bottom geophysical survey. Based on seismic stratigraphic analysis, observed geometries, and reflective appearances, six bounding surfaces and seven seismic units were identified and characterized. These seismic units have been correlated with the available borehole data to produce a chronologically constrained lithostratigraphy for the area. This approach allowed us to propose a relationship between the lithological units and sea-level change and thus enable the reconstruction of Hadera coastal evolution over the last ~ 100 ka. This reconstruction suggests that the stratigraphy is dominated by lowstand aeolian and fluvial terrestrial environments, subsequently transgressed during the Holocene. The results of this study provide a valuable framework for future national strategic shallow-water infrastructure construction and also for the possible locations of past human settlements in relation to coastal evolution through time.

Volcanic atolls host exceptionally important marine ecosystems in the modern oceans. Yet, due to limited exposures, fossil atolls are poorly constrained. Multiple drowned Cretaceous volcanic atolls have been reported in the Pacific, but less information exists regarding those in the Tethys. Here we report on two early Cenomanian age volcanic atolls outcropping in Mt. Carmel (northern Israel), along the eastern Levant margin. These atolls are a few kilometers in diameter and differ significantly in facies from their surroundings, which are dominated by chalky calcareous mudstone and wackestone. The atolls are composed of grainstone, floatstone, rudstone and bafflestone facies, which are dominated by molluscans, notably gastropods, rudists, oysters and other bivalves. Corals and green algae are absent throughout these atolls. The studied sections of these atolls display a full succession, beginning with aggradation and ending with drowning. Age constraints for the volcanic phases suggest that deposition occurred within a relatively short time interval (

Oil shows from wells in the Levant Basin and Egypt are suggestive of potential economic discoveries within unpenetrated Mesozoic reservoirs in the Eastern Mediterranean. Analysis of some of these oils indicate a non-marine source of mixed deltaic-terrestrial or lacustrine origin for the organic matter. Data from Barremian-Aptian sediments from the MNUPH-1 core in northern Israel opens a window on potential importance of terrestrial-sourced kerogen deposited in source rocks in a marine depositional environment. Core analyses of the Barremian Nabi Sa'id Fm. demonstrate the occurrence of a gas-prone immature source rock of >77 m gross thickness averaging 4.6% TOC, peaking at 37% TOC. Rock-Eval pyrolysis, biomarker n-alkane, sterane, and tricyclic terpane indices, atomic C/N ratios, and δ13Corg ranges indicate mixed terrestrial-marine organic source rocks for the Barremian, while higher up, the Aptian Hidra Fm. contains source rocks with organic matter derived dominantly from carbohydrate-rich land plants. The interval at MNUPH-1 includes abundant evidence for off-shelf mass transport of terrestrial and proximal marine sediments into the deep marine basin. These features are used to explain the anomaly of a terrestrial source for organic matter in this setting. Mass transport and consequent mixing of distal marine, proximal marine and land-derived sediment is, in fact, the norm at the foot of continental slopes globally. The dominantly type III source rocks described here would be unlikely to expel oil but might produce thermogenic gas. Thermogenic gas identified in similar marine settings might wrongly be interpreted as having been generated from marine organic matter, misleadingly indicative of a prospective oil source. When prospecting for deep-rooted hydrocarbon accumulations in offshore marine settings, an alternative system dominated by basinward sediment transport of gas-prone ‘terrestrial’ source rocks into strategically-positioned toe-of-slope marine settings, is supported here, and could well be producing gas in the Levant Basin.

Summary Analysis of high-resolution seismic reflection data reveals fluid-flow elements within the buried intra- to post-Messinian salt features and the overlying Plio-Quaternary unit of the Levant Basin. Additionally, natural methane seepages through seafloor sediments have been identified across the Nile deep-sea fan, Levant Basin, Eratosthenes Seamount, and other localities in the Eastern Mediterranean. Lastly, gas was discovered in sandstone of latest Miocene-Early Pliocene age at a depth of 1130 m and in Pleistocene calcareous sandstone units at depths of 300–450 m (the Noa-1, Mari-B, Nir, Or and Gaza Marine gas fields). The reservoir rock is the Yafo Sand Member, which is found at the base of the Pliocene Yafo Fm overlaying Messinian evaporites. However, the source rock of these biogenic gas discoveries is still unknown. We integrate geophysical and sedimentological/geochemical analysis of offshore well samples, with the intent of identifying these source rocks, and have identified three potential organic-rich (1–4 % TOC) source rocks, composed of gas-prone kerogen type III organic matter: a ∼200 m interval underlying the thick (1.8 km) MSC salt; discreet diatomite layers with a cumulative thickness of 25–40 m interbedded within the salt; a 20 m interval about 25 m above the top of the MSC unit.

This study presents evidences for fluid flow manifested as pipe structures in the post-evaporitic overburden characterised from a 3D seismic data from the Levant Basin, offshore central Israel. Interestingly these pipes are genetically and spatially contextualized east and west of the study area, all rooted in the Messinian evaporite substratum. Pipes in the western group accounts for 83% of the pipe population, are crudely cylindrical, oval to elliptical in planform, with diameter and height ranging ∼350–2000 m and ∼320–420 m, respectively. Internal configurations within this group varies from chaotic to concave upward reflections diagnostic of fluid induced collapse. Pipes in the eastern group are seepage pipes appearing conical in shape, with height of ∼350–510 m and diameter of ∼320–420 m. The eastern group pipes are characterized by lack of internal reflectivity and/or disrupted stratal reflections. The western group indicates an episode of fluid flow till the mid-Pliocene, compared to late Pliocene in the eastern group. A conceptual model for the pipes in the western group is proposed to have occurred from subjacent dissolution of the Messinian evaporite under deep-water marine conditions during the Pliocene by vertically focused fluid flow from intra-Messinian realm dissolving the top evaporites and inducing systematic collapse in the overburden, the onset of which may have been triggered by seismicity. Conversely, pipes in the eastern group are proposed to have developed from breaching the top evaporite by pressurized fluids that developed from lateral pressure transfer due to differential loading of the overburden and salt tectonics. These pipe structures may pose a potential risk to deep-water exploration and development. The fluid expulsion phenomena documented in this study has wider implications for the hydrodynamics of many basins where thick evaporite layers are widely developed.

This study presents geochemical evidence for biogenic methane formation (methanogenesis) in the shallow sediments of the oligotrophic SE Mediterranean continental shelf at water depths between 46 and 88 m. Depth-profiles of methane concentrations and related chemical parameters such as dissolved sulfate, dissolved inorganic carbon (DIC), and the stable carbon isotope composition of DIC and methane (δ 13 C DIC , δ 13 C CH4 , respectively) were measured in six sediment cores (each 4.2–5.4 m long) in order to characterize the processes that involve methane production and decomposition. All the sediment cores reached the consumption depth of the entire sulfate pool and the in-situ microbial methane production (methanogenesis) zone. Methane concentrations reached saturation levels in one of the cores, but not in the others, probably because the zone of maximum methanogenesis was at a greater depth. Although the sediments exhibit a low TOC content of ~1%, the biogenic methane formation indicates a relatively high organic carbon lability capable of sustaining all redox microbial activity potential. Anaerobic oxidation of methane (AOM) was also evident in the sulfate–methane transition zone, showing a distinct isotope signature in diffusion limited conditions.

A new high resolution bathymetric map of the Levant Basin between Israel and the Eratosthenes Seamount reveals previously undetected folds, faults and channels. The map facilitates a regional map-view analysis of structures that were previously examined only in cross section. The systematic mapping of morpho-structural elements in the entire basin is followed by a kinematic interpretation that distinguished between two main processes sculpting the seabed from bottom and top: salt tectonics and sediment transport. We show that the contractional domain related to salt tectonics is far more complex than previously thought. Ridges, previously interpreted as contractional folds are, in fact, surficial undulations of the seabed reminiscent of sediment waves. Moreover, other folds previously interpreted as downdip contraction of the westward gliding Plio-Quaternary section are, in some parts of the basin, caused by updip climbing of this section eastwards as a result of the regional pattern of salt flow away from the Nile Cone. In the context of sediment transport, we show that the northern Sinai continental slope is covered by a dense net of turbidite channels, whereas the Levant slope has no channels at all. Particularly interesting is the Levant Turbidite Channel, described and named here for the first time. This feature begins at the southeastern corner of the Mediterranean at water depths of ~ 1100 m, continues along the valley between the Sinai and Levant slopes, and reaches the deepest part of the basin, in water depths of ~ 2500 m, northeast of the Eratosthenes seamount. However, this prominent feature cannot be explained by the current drainage, consisting of two minor rivers that enter the basin at that point, and thus most likely reflects periods of wetter climate and/or lower sea-level, when these rivers were more active and possibly connected to the submarine channel system.

The northern Gulf of Elat/Aqaba is located in the transition between the deep marine basins of the gulf and the shallow onland basins of the Arava Valley. Interpretation of 500 km of high-resolution seismic reflection data collected across the northern shelf reveals the tectonic structure and evolution of this transition. Six NNE-trending faults and one E-W trending transverse fault are mapped. Slip rates are calculated based on measured offsets and age determination based on a radiocarbon-calibrated sedimentation rate and a Quaternary age model. The most active fault is the Evrona Fault that absorbs most of the left lateral slip within the basin with an average sinistral slip rate of 0.7 ± 0.3 mm/yr through the Late Pleistocene and 2.3–3.4 mm/yr during the Holocene. Two intrabasin faults east of the Evrona Fault that have been inactive for the last several tens of thousands of years were mapped, and motion from these faults has likely transferred to the Evrona Fault. The basin is flanked on the west by the Elat Fault and on the east by the Aqaba Fault. Both faults are marked by large bathymetric escarpments. Based on displaced seismic reflectors, we calculate a Holocene vertical slip rate of 1.0 ± 0.2 and 0.4 ± 0.1 mm/yr for the Elat and Aqaba Faults, respectively. The geometry, slip rates, and slip history of the northern Gulf of Elat/Aqaba faults show that during the Late Pleistocene several intrabasin faults became dominant across the basin but that during the Holocene the Evrona Fault accommodates most of the strike slip.

Methane (CH 4 ) is the most abundant hydrocarbon and one of the most important greenhouse gases in the atmosphere. CH 4 bubble growth and migration within muddy aquatic sediments are closely associated with sediment fracturing. In this paper we present the modeling of buoyancy-driven CH 4 bubble growth in fine-grained muddy aquatic sediment prior to the beginning of its rise. We designed a coupled mechanical/reaction-transport numerical model that enables a differential fracturing over the bubble front (as it occurs in nature), when the fracturing increment stays constant at the bubble head and subsides towards bubble tail during bubble growth. We show that this differential fracturing over the bubble front controls the bubble shape and size temporal evolution, and is significantly affected by the critical stress intensity factor of the muddy sediment. The intercalated stages of elastic expansion and fracturing during the bubble growth shorten with time as the bubble approaches its terminal size (prior to its ascent). Our simulations reveal a high asymmetry in the bubble shape growing with time, with respect to its initial symmetric penny-shaped configuration. It was found that the bubble grows allometrically, while the importance of the bubble surface area growth with time. We also confirmed the earlier predictions about the ”inverted tear-drop” bubble cross-section just prior to the beginning of its rise. Modeling of the terminal bubble characteristics will permit prediction of the delivery of gaseous methane from the sediment to the atmosphere via the water column.