Eratosthenes Seamount Research Articles

Echinoderid mud dragons (Cyclorhagida: Kinorhyncha) from Senghor Seamount (NE Atlantic Ocean) including general discussion of faunistic characters and distribution patterns of seamount kinorhynchs

Investigation of Kinorhyncha from Senghor Seamount (tropical northeastern Atlantic Ocean) and the adjacent deep-sea floor revealed seven species of Echinoderes. Of these, Echinoderes kaempfae sp. nov. and Echinoderes schwieringae sp. nov. are described as new species. Echinoderes multiporus originally found on Eratosthenes Seamount, Mediterranean Sea, and Echinoderes cf. adrianovi originally found off Florida, northwestern Atlantic Ocean, were also recovered. In addition, three additional species, which possibly represent undescribed species, occurred on Senghor Seamount. Because of the low number of available specimens or necessity of further observations of closely related congeners for these three undescribed species, we provide only a brief description of them without naming them as new species. The comparison of each species with morphologically similar congeners is also provided. Based on all records of kinorhynchs from seamounts and the adjacent deep-sea floor in the Northeastern Atlantic Ocean, Mediterranean Sea, and Arctic Sea, it is suggested that (1) the kinorhynch fauna on seamounts is partly unique, (2) seamount kinorhynchs originate both from shallow waters and the deep sea, and (3) a few kinorhynch species diversified on seamounts.

Environmental evolution and geological significance of the Miocene carbonates of the Eratosthenes Seamount (ODP Leg 160)

Miocene carbonates of the Eratosthenes Seamount, located offshore from Cyprus in the Eastern Mediterranean (ODP Leg 160, Site 966), have been re-analysed. The use of SEDEX sequential extraction to evaluate the nutrient concentrations and of CT-Scan for the identification of large benthic foraminifera has resulted in a more detailed palaeoenvironmental reconstruction and an improved stratigraphic framework. Three intervals are recognised in the succession and are attributed to the lower, middle and upper Miocene, respectively. The lower Miocene interval is dominated by large benthic foraminifera and echinoids. This association colonized the top of the seamount following its uplift from deep-water to the photic zone. The middle Miocene interval is characterised by rhodoliths and corals at its base and near the top, whereas seagrass/seaweed assemblages (with epiphytic foraminifera and hooked coralline-algal crusts) dominate its central part. The upper Miocene is represented by coral reef facies near its base and lagoonal facies toward its top. The succession was deposited in an oligotrophic environment and exhibits a general shallowing-upward trend that was mainly controlled by tectonic activity related to the northward subduction of the African plate. The succession of the Eratosthenes Seamount is characterised by a diverse large benthic foraminifera assemblage in its lower part and by corals in its uppermost part, whereas corallines characterise the central interval. This trend is common in Miocene Mediterranean carbonates and its occurrence on an isolated seamount confirms its connection with the general evolution of the basin. The decline of miogypsinids and lepidocyclinids after the early Miocene is notable because the Eratosthenes Seamount was geographically close to the Indo-Pacific Ocean where both groups also thrived during the middle Miocene. This decline was probably caused by the early Miocene closure of the deep-water connection between the Indo-Pacific and the Mediterranean.

Geochemical and petrographic investigation of Triassic and Late Miocene organic-rich intervals from onshore Cyprus, Eastern Mediterranean

In order to improve the understanding of potential petroleum systems in the still underexplored Eastern Mediterranean Sea, two field campaigns were performed to investigate potential source rocks onshore Cyprus. Elemental data (total organic (TOC) and inorganic carbon (TIC), total sulfur (TS), Fe, Ni, V), Rock-Eval® pyrolysis, biomarker and microscopic analysis (organic petrography, random vitrinite reflectance (VRr), palynofacies) of the obtained Mesozoic to Cenozoic samples have proven the existence of organic matter (OM) rich deposits within the following two geological formations:(1)The Triassic Vlambouros Formation (Fm.) of the Mamonia Complex comprises frequently occurring, few centimeter thin clay layers interbedded between meter thick sandstone units. The clay layers of this formation are characterized by TOC contents of about 1 wt% representing a Type III kerogen showing hydrogen index (HI) values of 48 mg HC/g TOC on average. VRr values of 0.5 to 0.6% as well as several biomarker ratios indicate low thermal maturity. The formation was deposited at the northern margin of Gondwana and similar strata may be present in the basement of the Levant Basin and the Eratosthenes Seamount. There, thermal maturity would be higher and such rocks might contribute to thermogenic gas systems.(2)In the Miocene Pakhna Fm., OM-bearing intervals are mainly present in the upper part of the formation in outcrops east of the Troodos Mountain, while organic-rich intervals are very scarce to absent in the south and southwest of the island. The eastern outcrops show abundant fine-grained, (marly) mud- to wackestones interbedded with coarser-grained carbonates. The fine-grained intervals have TOC contents of about 4 wt% representing mainly Type II-III kerogen with HI values of 238 mg HC/g TOC on average. The OM is immature as indicated by VRr values between 0.3 and 0.5%. TS/TOC ≥ 2.8 and several biomarker ratios indicate oxygen-depleted, even anoxic conditions during deposition. A negative correlation between the TOC and TIC indicates that such conditions were reached during enhanced primary bioproductivity controlled by local and regional clastic derived nutrient input. Similar conditions may have been present along the southeastern margin of the Eratosthenes Seamount, south of Cyprus. Presence of abundant organic matter and high sedimentation rates during the Miocene were favorable for microbial gas generation in the deeper parts of the basins.

The tectonic evolution of the eastern Mediterranean basin and its control on hydrocarbon distribution

Recent discoveries of giant, deep-water gas fields in the Eastern Mediterranean Basin (EMB) have revealed abundant hydrocarbon resources and significant exploration potential in turbidite and reef reservoirs (e.g., in the Tamar and Levantine fields, and the Zohr and Calypso fields, respectively). However, further exploration is currently constrained by the lack of detailed knowledge on the development of the basin. This paper presents a systematic model of the tectonic evolution of the EMB based on an analysis of new 2D seismic data and relevant published literature, assesses the main petroleum systems operating in the basin, and identifies prospective zones for future exploration. The modeling of a sequence of 12 prototype basins, restored from the seismic data, enable the tectonic evolution of the EMB to be divided into three stages: a rift stage, a ‘drift’ stage (including post-rift thermal subsidence), and a ‘convergence and transformation’ stage. This latest stage can be divided into four chronologically and geographically distinct sub-stages.The structural and stratigraphic architecture of the EMB, and hence the hydrocarbon distribution in the basin, evolved during the rifting of continental fragments from Gondwana (e.g., the Tauride–Anatolian plate, and the Kyrenia, Troodos, and Eratosthenes micro-plates), followed by their northward drift and collision with Eurasia. Six hydrocarbon plays are identified in this paper, two of which are previously unrecognized: the Mesozoic intra-platform reef play in the Eratosthenes Seamount, and the Mesozoic and Miocene ‘double-stacked’ platform-margin reef play in the ‘high–low structure belt’ south of the Eratosthenes Seamount. These two high-quality reef plays, together with stratigraphic and fault-block traps in the northern Levant Basin, are identified as the most prospective hydrocarbon exploration targets in the EMB.

Mode conversion noise attenuation, modelling and removal: case studies from Cyprus and Egypt

The wavefront from a source that strikes an acoustic impedance contrast separates into four variables: transmitted and reflected compressional waves (P-wave) and transmitted and reflected shear waves (S-wave). Converted waves are those whose mode changes at the interface and can be recorded in a marine environment in the presence of large velocity contrasts. The difference in acoustic velocities at the boundary means that in high contrast media the distinction between compressional and shear velocities across the boundary is small; shear waves are not as refracted as compressional waves and can be recorded as partially converted reflected energy. The eastern Mediterranean contains two major sedimentary basins, the Levantine and Herodotus (see Figure 1). They have shared depositional regimes and therefore contain similar sedimentary sequences. The Levantine Basin sits offshore Cyprus, Israel, Palestine and Lebanon, and was formed by prolonged phased rifting, with subsequent subsidence and loading by deltaic sediments (Gradmann et al., 2005; Gardosh and Druckman, 2006). It forms a northeast-oriented depression about 2 km deep and contains more than 14 km of Mesozoic and Cenozoic sequences that include up to 2 km of Messinian salt (Druckman et al., 1995; Ben-Avraham et al., 2002; Netzeband et al., 2006). The local reservoirs include both Cretaceous and Jurassic sandstones and limestones, with older potential reservoirs in the Triassic sandstones. Shales and marls of Paleogene, Neogene, Cretaceous and Jurassic, along with Messinian salt and Triassic evaporites all form local seals (Roberts and Peace, 2007) in plays of a both stratigraphic and structural nature. The Herodotus Basin is a northeast trending 3 km deep depression, and represents a slab of the Early Mesozoic Neo-Tethys Ocean (see Figures 1 and 2). The basin is bounded on the north by the Mediterranean Ridge; on the northeast by the west portion of the Cyprus Arc and on the south by the Nile Delta cone. The Eratosthenes Seamount (ESM), a fragment of continental crust (Robertson, 1998), forms the eastern limit of the Herodotus Basin, and additionally delineates the boundary between the cone of the Nile Delta, the Herodotus Basin, and the Levant Basin. The Herodotus Basin itself contains up to 7 km of Mesozoic–Cenozoic sediment (Voogd and Truffert, 1992; Garfunkel, 1998), and is overlain by up to 3 km of Messinian salt (Garfunkel, 1998; Aal et al., 2000; Loncke et al., 2006).

Structural pattern recognition applied on bathymetric data from the Eratosthenes Seamount (Eastern Mediterranean, Levantine Basin)

The scope of the present work is to apply tested techniques of pattern recognition on bathymetric data from the Eratosthenes Seamount to (a) detect topographic highs and linear-curvilinear lineaments present on the seabed, (b) evaluate the morphostucture of the seamount and its relation with the degree of deformation the region has suffered, and (c) to check if shallow salt movements are associated with specific patterns on bathymetric data. Our scope is implemented by applying a two-step procedure on bathymetric data. Initially, the topographic highs in the study area are detected and their geomorphologic attributes (orientation, average slope, eccentricity, and shape complexity) associated with the degree of seabed deformation are computed. Then, quantitative attributes (slope, aspect, and their derivatives) are combined to automatically detect seabed morphologic structures (lineaments, highs, or depressions), which are potentially related to the presence of geological faults or triggered by other subsurface processes. Based on the analysis in this work, two major segments (the northern and the southern) are identified on the Eratosthenes Seamount and related to E–W trending oblique faults. These two segments are highly deformed according to the quantitative estimation of the geomorphologic attributes. Furthermore, ENE–WSW to NE–SW and WNW–ESE to NW–SE lineaments are identified and limit this prominent topographic high. Smaller topographic highs accompanied by topographic depressions, north and southwest of the Eratosthenes Seamount are also detected, showing medium to strong deformation and reflecting a similar geodynamic activity in this area. As a corollary, a comparison of the bathymetric patterns shows that the present seabed morphology north of the Eratosthenes Seamount relates to shallow salt movements, which create a chaotic pattern. This pattern is expressed by short and curved normal faults, shear zones, possible small-scale reverse faults, massive extrusion of salt bodies (possibly allochthonous), and Pliocene–Quaternary minibasins or peripheral sinks.

Calcareous nannofossil palaeoenvironmental reconstruction and preservation in sapropel S1 at the Eratosthenes Seamount (Eastern Mediterranean)

The most recent organic carbon-enriched layer (sapropel S1) deposited at the Eratosthenes Seamount has unique features, such as an early lithological interruption, fine light silt laminae and an exceptional vertical extent that is over 25 cm thick. Here we investigate calcareous nannofossil assemblages to reconstruct very high-resolution palaeoenvironmental and palaeoceanographic variations recorded before, during and after the perturbation episode that involved the eastern Mediterranean Sea, due to the massive freshwater discharge via Nile River. Our results show that the deep chlorophyll maximum development, observed in all micropalaeontological groups from previous studies, is a gradual process that started well before the base of sapropel S1. A high-frequency variability in the nutricline depth is evident at millennial- and/or centennial-scale throughout the sapropel deposition time interval. Also we highlight the poor-preservation of delicate tiny holococcolith crystals while anoxia was occurring at the seafloor and we suggest that such a phenomenon may be used to mark the original thickness of sapropel deposition where oxygen re-ventilation fronts were developed. Finally, calcareous nannofossil reworking peaks shed light on the nature of fine silt laminae within the sapropel S1 at the Eratosthenes Seamount, which may be ascribed to fine sediment plumes from the Nile River deposited during exceptional runoff events.

Velocity model building in the major basins of the eastern Mediterranean Sea for imaging regional prospectivity

Hydrocarbon prospectivity in the eastern Mediterranean is challenged by the presence of the Messinian salt layer, which varies in complexity across the area. The macro salt layer geometry itself varies from the deep abyssal planes in the middle of two major basins (the Herodotus and Levant basins), where it shows simple top and base relief to more complicated geometries near the continental salt-free shelf. Building depth velocity models for imaging the eastern Mediterranean basins requires accurate determination of the complex salt top and base, as well as accurate estimation of their velocities. Since 2006, many 2D and 3D megasurveys using conventional and dual-sensor acquisitions have been carried out across the area. Regional and relatively simple velocity models are used to image the Messinian salt layer extensions from offshore West Egypt to offshore Lebanon, passing by the Cypriot waters and the Eratosthenes Seamount. The data acquired include shallow and deepwater surveys, and technologies such as full-waveform inversion are applied to produce high-resolution images for the shallow post-Messinian section. Shallow-water imaging challenges such as acquisition footprint issues and low-angle illumination are solved by imaging with multiples using dual-sensor acquisition data. The Messinian salt layer is modeled with a simple constant regional velocity, while the pre-Messinian section is modeled with a simple combination of velocity gradient models. The regional model-building scheme introduces a good correction for the pre-Messinian structure and provides reliable multiclient data ready for outlining new prospects.

New species of Echinoderes (Kinorhyncha: Cyclorhagida) from Mediterranean seamounts and from the deep-sea floor in the Northeast Atlantic Ocean, including notes on two undescribed species.

Two new species of Echinoderes from the Eratosthenes Seamount and a deep-sea station near the Sedlo Seamount are described. Echinoderes multiporus sp. nov. from the Eratosthenes Seamount is characterized by a combination of the presence of middorsal acicular spines on segments 4, 6, and 8, ventrolateral tubes on segment 2, lateroventral tubes on segment 5, lateroventral acicular spines on segments 6-9, midlateral tubes on segment 10, and type-2 glandular cell outlets in subdorsal position on segment 2 and in laterodorsal position on segments 4-9. Echinoderes unispinosus sp. nov. from the deep-sea station differs from its congeners by the combination of middorsal acicular spine on segment 4, lateroventral acicular spines on segments 6 and 7, type-2 glandular cell outlets present in midlateral position on segment 1, in subdorsal, laterodorsal, sublateral, and ventrolateral position on segment 2, in lateral accessory position on segment 5, and in sublateral position on segment 8, and densely aligned pectinate fringe teeth of the primary pectinate fringes similar in width on segments 1-10. In addition, the morphological data of two undescribed species from the Anaximenes Seamount and a deep-sea station near the Sedlo Seamount are given. An undescribed species from the Anaximenes Seamount is morphologically similar to Echinoderes unispinosus sp. nov., but differs in the smaller trunk length, the presence of broader pectinate fringe teeth of the primary pectinate fringe on segment 1, and the absence of ventromedial sensory spots on segment 8. Another undescribed species from the deep-sea station differs from its congeners in the pattern of spines, tubes, and type-2 glandular cell outlets and length of middorsal and lateral terminal spines. New names are not given to both undescribed species in this study, because only one specimen is available for each species, and both of the specimens were damaged during the preparation.

Tectono-stratigraphic evolution of the western margin of the Levant Basin (offshore Cyprus)

Abstract Stratigraphic interpretation of twenty-four 2D seismic reflection profiles coupled with available well data from the Ocean Drilling Program (ODP) offshore Cyprus enabled identification of the main unconformities and the seismic packages in the western part of the Levant Basin and their correlation with major geodynamic events. The basic concepts of seismic stratigraphy were applied to improve our understanding of the tectonostratigraphy and the sedimentary architecture of Eratosthenes isolated carbonate platform. This platform is composed of dominant retrograding and aggrading Mesozoic carbonate build-ups and its evolution partly resembles that of the Egyptian margin. Deep-water mixed carbonates and siliciclastics probably prevailed in the basin during the Early Cretaceous. During the Late Cretaceous, these platforms were drowned. Following the convergence of the two plates, both the Eratosthenes Seamount (ESM) area and the Levant Basin progressively became part of a foreland basin along the Cyprus Arc. Different units in the Eratosthenes carbonate platforms (ECPs) and the transition to the deep Levant Basin are detailed here for the first time. We present a 3D conceptual model for the evolution of the western margin of the Levant Basin. We discuss the effect of the Miocene collision between the Cyprus Arc and Eratosthenes to understand the presence of upper Miocene Mass transport complexes (MTCs) in the deep basin and the tilting of the top of the adjacent ECPs. We briefly examine the deformation mechanisms of the Messinian salt near the paleo-shelves of the ECPs.

Source rock characterization of mesozoic to cenozoic organic matter rich marls and shales of the Eratosthenes Seamount, Eastern Mediterranean Sea

Several significant hydrocarbon accumulations were discovered over the past decade in the Levant Basin, Eastern Mediterranean Sea. Onshore studies have investigated potential source rock intervals to the east and south of the Levant Basin, whereas its offshore western margin is still relatively underexplored. Only a few cores were recovered from four boreholes offshore southern Cyprus by the Ocean Drilling Program (ODP) during the drilling campaign Leg 160 in 1995. These wells transect the Eratosthenes Seamount, a drowned bathymetric high, and recovered a thick sequence of both pre- and post-Messinian sedimentary rocks, containing mainly marine marls and shales. In this study, 122 core samples of Late Cretaceous to Messinian age were analyzed in order to identify organic-matter-rich intervals and to determine their depositional environment as well as their source rock potential and thermal maturity. Both Total Organic and Inorganic Carbon (TOC, TIC) analyses as well as Rock-Eval pyrolysis were firstly performed for the complete set of samples whereas Total Sulfur (TS) analysis was only carried out on samples containing significant amount of organic matter (>0.3 wt.% TOC). Based on the Rock-Eval results, eight samples were selected for organic petrographic investigations and twelve samples for analysis of major aliphatic hydrocarbon compounds. The organic content is highly variable in the analyzed samples (0–9.3 wt.%). TS/TOC as well as several biomarker ratios (e.g.Pr/Ph < 2) indicate a deposition under dysoxic conditions for the organic matter-rich sections, which were probably reached during sporadically active upwelling periods. Results prove potential oil prone Type II kerogen source rock intervals of fair to very good quality being present in Turonian to Coniacian (average: TOC = 0.93 wt.%, HI = 319 mg HC/g TOC) and in Bartonian to Priabonian (average: TOC = 4.8 wt.%, HI = 469 mg HC/g TOC) intervals. A precise determination of the actual source rock thickness is prevented by low core recovery rates for the respective intervals. All analyzed samples are immature to early mature. However, the presence of deeper buried, thermally mature source rocks and hydrocarbon migration is indicated by the observation of solid bitumen impregnation in one Upper Cretaceous and in one Lower Eocene sample.

Wayfarers of the ancient world

Ben Ballard and his colleagues explore the Eratosthenes seamount, an underwater plateau south of Cyprus, on expeditions supported by the Ocean Exploration Trust (OET). The team found two shipwrecks and 70 artefacts and they discovered a third shipwreck and 149 further artefacts. Eratosthenes seamount is an ideal preservation site because of its depth. Ballard says the Mediterranean seabed probably holds thousands of wrecks from the last few millennia.

Deep-water archaeological discoveries on Eratosthenes Seamount

A team of earth scientists conducted a series of exploratory transects across the summit of Eratosthenes Seamount in 2010 and 2012 to better understand the geologic structure of this unique flat-topped feature in the East Mediterranean Sea. The team encountered 219 isolated amphorae and 3 shipwrecks using remotely operated vehicles equiped with both acoustic and optical image systems. The researchers could instantaneously communicate with archaeologists on shore by utilizing a high bandwidth satellite system on the E/V Nautilus. This system allowed researchers and archaeologists to better take advantage of this series of discoveries. The data collected during these field seasons, presented and discussed in this article, contributes to existing literature on the maritime traffic patterns of the ancient Eastern Mediterranean, and of open-sea travel over the underwater plateau from 800 BC—800 CE.

Structural implications of strain localization towards a continental transform fault: The example of the shift between the Levant margin and the Dead Sea Fault plate boundary

Continental transform faults accommodate lateral motion between two adjacent plates. Often, evidence for such motion is hard to detect due to onland processes of erosion. Investigation of a submerged passive continental margin adjacent to a transform plate boundary might provide indications for the developmental stages of the transform. To examine this hypothesis, we analyzed the Messinian-to-recent stratigraphy and structure of the Levant continental margin that resides ca. 100 km from the Dead Sea fault (DSF) continental transform. The analysis is based on interpretation of seismic reflection data (2D and 3D time migrated, and pre-stack 3D depth migrated) and four boreholes. It includes construction of structural maps, tracking of stacking patterns and calculations of sedimentation rates. Data show that the Levant margin developed through three phases: (1) Late Miocene-Earliest Zanclean (∼6-∼5 Ma) NNE-SSW left lateral strike-slip faulting (2) Zanclean-Late Gelasian (∼5–1.8 Ma) syn-depositional folding striking in the same direction. The top Gelasian surface marks an abrupt change, which is expressed as (3) mass slumping that occurred due to regional basinward tilt. Continuation of differential subsidence is manifested by Calabrian-to-recent progradation (1.8–0 Ma). While Nile sediment flux peaked at 1.8 Ma and decreased during the Calabrian-to-recent, our data shows an increase in sedimentation on the Levant margin throughout the entire Plio-Pleistocene. This discrepancy is caused by the regional tilting of phase 3, which shifted the depocenter to the west. Correlations to onshore findings suggest that the faulting, folding and tilting observed on the continental margin represent localization of strain towards the DSF during the Pliocene-Gelasian (5.3–1.8 Ma). This is attributed to the consequent deepening of the DSF and the incipient collision of the Eratosthenes Seamount with the Cyprus Arc. The continental margin records the development of the nearby active transform through structural and sedimentary modifications.

Structural characteristics and petroleum exploration of Levant Basin in Eastern Mediterranean

Abstract By using geologic and seismic data, this study restored the proto-type basins and lithofacies paleogeography of the Levant basin in Eastern Mediterranean during main geological periods, carried out comparison analysis on the basin architecture characteristics, and based on careful examination of the characteristics of discovered gas reservoirs, established the reservoir forming pattern and discussed the favorable reservoir forming combinations and future exploration direction in this region. Three structural architectures can be identified in the basin, the early-stage faults, the mid-stage faults and the late-stage faults. The early-stage faults are mainly controlled by intercontinental depression, which were less influenced by later compression stress in the southern deep water area of the basin. Controlled by the lateral structural stress and the Syrian Arc Fold Belt, the mid-stage faults became less active from north to south and from east to west. Influenced by the collision and/or Dead Sea strike-slip Fault Zone, the late-stage faults were active but did not pierce the thick Upper Miocene evaporites. Combined with the discovered reservoirs and outcrops, the Mesozoic sandstones and carbonates in deep water area near Eratosthenes seamount of Israel offshore and the Cenozoic carbonates and Tamar sands of Lebanon offshore are the main petroleum exploration targets in the next step.

Crustal structure of the Eratosthenes Seamount, Cyprus and S. Turkey from an amphibian wide-angle seismic profile

In 2010, project CoCoCo (incipient COntinent-COntinent COllision) recorded a 650km long amphibian N-S wide-angle seismic profile, extending from the Anatolian plateau across southern Turkey and Cyprus to just south of the Eratosthenes Seamount (ESM). The aim of the project is to reveal the impact of the transition from subduction to continent-continent collision of Africa with Anatolia. Arrival picking, finite-differences ray-tracing and inversion of the offshore and on-offshore data produced a tomographic model across southern Cyprus, the accretionary wedge and the ESM. The main features of this model are (1) crustal P-velocities predominantly lower than 6.5km/s beneath the ESM, (2) crustal thickness between 28 and 37km, (3) an upper crustal reflection at 5km depth beneath the ESM, (4) the likely presence of oceanic crust south of the ESM and a transform margin north of it and (5) a 12km thick ophiolite sequence on Cyprus. Land shots on Turkey, also recorded on Cyprus, gravity data and geological and previous seismic investigations allow to derive a layered velocity model beneath Anatolia and the northern part of Cyprus. The main features of this model are (1) Moho depths of 38–45km beneath the Anatolian plateau, (2) an upper and lower crust with large lateral changes in velocity and thickness, (3) a north-dipping subducting plate below Cyprus with a steepening of the dip-angle of the plate at about 45km depth. Thus, the wide-angle seismic and gravity data provide detailed insights into the 2-D geometry and velocity structures associated with the Cyprus Arc collision zone. Finally, integrated analysis of the geophysics and geology allows a comprehensive interpretation of the crustal structure related to the collision process.

Active faults in the Anatolian-Aegean plate boundary region with Nubia

Convergence of the Africa, Arabia, and Eurasia plates and the westward escape of Anatolia have resulted in an evolving plate boundary zone in the Eastern Mediterranean. e current location and nature of the plate boundary between the Anatolian and the African plate is di cult to trace due to the scattered crustal earthquakes and the absence of deep ones. We examine various types and locations for the plate boundary as constrained by seismicity, seismic re ection studies, tomographic studies, and geodetic measurements and we use a spherical plane stress nite element model to test these possibilities. In our regional model, we impose the convergence of Africa, Arabia, and stable Eurasia by applying GPS-derived velocities in the far- eld, as well as the roll-back of the Hellenic trench to solve for regional deformation. Model velocity and stress elds are compared with GPS-derived velocities and stress directions from focal mechanism solutions. We nd that the plate boundary via the Pliny and Strabo trenches, the Anaximander Mountains, the Eratosthenes Seamount collisional segment, and the Latakia-Larnaka ridges gives the best t to the data. e Anaximander Mountains plate boundary has both down-dip and strike-slip motions, and the Latakia segment is pure strike-slip. e Cyprus subduction contact is 42% locked. From a combined analysis of indicators for long-term deformation (predominantly slip-rates on major faults) and model results we infer that this southern plate boundary con guration may have existed since the Late Pliocene.

Quantitative dating of Pleistocene deposits of the Kyrenia Range, northern Cyprus: implications for timing, rates of uplift and driving mechanisms

The Kyrenia Range underwent tectonically driven uplift during the Pliocene to Pleistocene in response to the interaction of various tectonic processes. To understand the tectonic processes driving the uplift and how this is related to uplift of other areas of the Eastern Mediterranean, uranium-series disequilibrium and optically stimulated luminescence dating were applied to marine and non-marine terrace deposits exposed on the northern flank of the range. Palaeomagnetism and strontium isotope dating were used in conjunction to date the final stages of the marine environment adjacent to the Kyrenia Range prior to major surface uplift. Uplift rates range from >1.2 mm a −1 , inferred during the Early Pleistocene, to <0.2 mm a −1 during the Late Pleistocene. The new data show that the Kyrenia Range was uplifted contemporaneously with the Troodos Massif in southern Cyprus. The uplift of the Kyrenia Range appears to have been significantly faster than that affecting other comparable regions in the easternmost Mediterranean during the Pleistocene (e.g. Lebanon coast; southern Anatolian plateau). The driving mechanism for the uplift of both the Kyrenia Range and the Troodos Massif is inferred to be the collision of the Eratosthenes Seamount with the Cyprus trench to the south of Cyprus. Supplementary material : Details of the methods used are available at https://doi.org/10.6084/m9.figshare.c.3260977 .

Active tectonic trends and crustal modeling of the eastern Mediterranean Sea deduced from geophysical data

The eastern Mediterranean Sea is considered as a highly tectonic region evolving from the progressive African-Eurasian collision. The current research is an attempt to resolve the problems related to the geodynamic evolution of this region to delineate the main tectonic trends, the nature and thickness of the crust. These tectonic trends have played a very significant role in the most recent discovery of large gas fields in the mapped region. This has drawn the attention to the needs to investigate this region more thoroughly. Published gravity and magnetic data are utilized and analyzed using the most recent proposed techniques. The integration of the implemented methods revealed more new tectonic trends. The NW–SE trend is the major trend that is associated with Temsah and Misfaq-Bardwil trend while the NE–SW trend that is associated with Rosetta and Eratosthenes Seamount trends. The N–S trend that is associated with Baltim fault trend and another E–W trend is associated with the Neogene hinge zone and the Cyprian Arc. Moreover, a NNE–SSW related to the Tartus thrust trend and the Gulf of Aqaba was observed, in addition to an ENE–WSW trend relates to the Kyrenia-Missi trend. The observed WNW–ESE direction relates to the Animaxander Seamount trend and finally the NNW–SSW trend. Based on the delineated tectonic trends, the mapped region was classified into four main basins namely the Shelf basins, the Margin-dominated basins, the Deep basins, and the Levantine basin to the east. The depth to the basement is an irregular surface and gradually changes from more than 13 km in the northern part and decreases to less than 6 km in the southeastern Mediterranean Sea.

The enigma of the Jonah high in the middle of the Levant basin and its significance to the history of rifting

Recent giant gas discoveries within deeply buried structural highs in the middle of the Levant basin have attracted the attention of the industrial and academic communities striving to understand the origin of such structures, their relations to the tectonic history of the basin, and their evolution through time. Here we focus on the Jonah high, which is one of the largest structures in the basin and is particularly enigmatic in its geometry, dimensions and location compared to nearby structures. It is buried under more than 3km of Late Tertiary sediments, and is associated with one of the largest magnetic anomalies in the basin, though no significant gravity anomaly is observed. Previous studies raised several possibilities explaining its origin: an ancient horst related to the early stage of basin formation (Late Paleozoic or early Mesozoic); a Syrian Arc fold (Late Cretaceous to Neogene); a giant volcanic seamount; and an intrusive magmatic body.A reconstruction of the evolution of this structure is proposed here based on newly produced pre-stack depth migration of five selected seismic reflection lines crossing the Jonah high combined with a basin-wide interpretation of more than 500 2-D time-migrated lines. We suggest that the Jonah high is a horst bounded by grabens, most probably formed during continental breakup related to the Neo-Tethys formation. However, unlike other extensional structures that were reactivated and inverted during the Syrian Arc deformation, the Jonah high was never reactivated. Rather, it formed a prominent seamount that persisted for 120–140Ma until the Early Miocene, when it was finally buried. In a wider perspective the Jonah horst is similar to the Eratosthenes seamount, a fragment of continental crust between the Levant and Herodotus basins.