Levant Margin Research Articles

Internal deformation of the southeast Levant margin through continued activity of buried mass transport deposits

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.

Hierarchy of source-to-sink systems — Example from the Nile distribution across the eastern Mediterranean

A standard source-to-sink approach examines sediment transport along an imaginary axis (regarded here as primary) extending between land, the continental margin and a nearby basin. This approach oversimplifies the development of depositional environments located off the axis (regarded here as secondary). Similarly, it imposes that factors affecting the primary source (e.g. climate) will directly be reflected in the secondary sink. The current study examines this suggested hierarchy in a confined basin, where the sedimentary budget remains closed. It evaluates the mechanism connecting between the primary and secondary axes. The study focuses on the Nile sedimentary system, across northeastern Africa and the eastern Mediterranean basin (primary axis) and the Levant depositional system (secondary sink). We hypothesize that since secondary river input into the Levant basin is negligible, the main secondary source is seafloor currents. The Levant Jet System (LJS) transported sediments from the Nile cone along the Levant margin at depths between 0 and 350m, during the Holocene and until today. Once the LJS reaches its capacity to transport sediments, the surplus falls downslope to the deep basin. By integrating seismic and bathymetric data, this paper suggests a unifying mechanism integrating deposition, erosion and transport of sediments across the Levant margin and basin throughout the Quaternary. Results show that during both highstand and lowstand conditions the primary source-to-sink axis delivers sediments to the deep basin via south to north meandering channels. The LJS transports sediments that build the shelf, while unconfined overspills slide downslope to accumulate across the continental rise. However, when sea levels drop, the capacity of the LJS weakens. This results in a drastic decrease in sedimentation across the shelf and rise, accompanied by confined downslope turbidity flows into the deep basin. We conclude that seafloor currents serve as an immediate supplier from the mouth of the primary source (i.e. a major river) to the off-axis system. Variations in seafloor current dynamics and their capacity to transport sediments will be directly reflected in the secondary sink. The primary continental source is expected to have only an indirect effect on the secondary sink.

Stromatolitic biotic systems in the mid-Triassic of Israel — A product of stress on an epicontinental margin

Phanerozoic microbialites are carbonate-precipitating biotic forms that are often described in modern systems from inter- or supratidal, hypersaline or fresh-water environments, and from beds associated with a variety of ecologically stressed environments, over geologic time. Middle to Late Triassic microbialitic successions from southern Israel were commonly subtidal, and thrived under cryptic ecological stress conditions related to the regional configuration of the Levant margin at that time.The Ladinian and Carnian sequence at the Ramon outcrop contains 18 successions with 28 microbialitic horizons. These microbialites form isolated patches, small bioherms and biostromes interleaved with other calcareous sediments including poorly diverse molluscan accumulations. Three distinct microbialitic facies and two associated molluscan facies were identified. Most were distinctly subtidal. The two associated molluscan biofacies include a subtidal bivalve boundstone forming mounds, and a bedded packstone of minute gastropods.The Ladinian–Carnian microbialites were not climatically forced. Environmental stress was caused by partial restriction of marine circulation due to tectonic movements and biotic accumulation on the outer edge of the Levant margin. Comparison of coeval successions from central and northern Israel and the North Calcareous Alps and Southern Alps in Europe, indicates a Tethyan or global carbonate system of microbial producers separated from the open marine environment by shelf-edge barriers. Therefore, we conclude that the Ramon microbialites represent a response to ecological stress of the carbonate system within the subtidal environment, rather than solely to normal stresses of the intertidal environment.

Crustal seismic velocity structure from Eratosthenes Seamount to Hecataeus Rise across the Cyprus Arc, eastern Mediterranean

Wide-angle reflection/refraction seismic profiles were recorded across the Cyprus Arc, the plate boundary between the African Plate and the Aegean–Anatolian microplate, from the Eratosthenes Seamount to the Hecataeus Rise immediately south of Cyprus. The resultant models were able to resolve detail of significant lateral velocity variations, though the deepest crust and Moho are not well resolved from the seismic data alone. Conclusions from the modelling suggest that (i) Eratosthenes Seamount consists of continental crust but exhibits a laterally variable velocity structure with a thicker middle crust and thinner lower crust to the northeast; (ii) the Hecataeus Rise has a thick sedimentary rock cover on an indeterminate crust (likely continental) and the crust is significantly thinner than Eratosthenes Seamount based on gravity modelling; (iii) high velocity basement blocks, coincident with highs in the magnetic field, occur in the deep water between Eratosthenes and Hecataeus, and are separated and bounded by deep low-velocity troughs and (iv) one of the high velocity blocks runs parallel to the Cyprus Arc, while the other two appear linked based on the magnetic data and run NW–SE, parallel to the margin of the Hecataeus Rise. The high velocity block beneath the edge of Eratosthenes Seamount is interpreted as an older magmatic intrusion while the linked high velocity blocks along Hecataeus Rise are interpreted as deformed remnant Tethyan oceanic crust or mafic intrusives from the NNW–SSE oriented transform margin marking the northern boundary of Eratosthenes Seamount. Eratosthenes Seamount, the northwestern limit of rifted continental crust from the Levant Margin, is part of a jagged rifted margin transected by transform faults on the northern edge of the lower African Plate that is being obliquely subducted under the Aegean–Anatolian upper plate. The thicker crust of Eratosthenes Seamount may be acting as an asperity on the subducting slab, locally locking up subduction of the Cyprus Arc on its northern margin, while deformed Tethyan oceanic crust remains trapped between its northeastern margin and the Hecataeus Rise.

Physiographic discontinuity along the Levant-Margin hinge-belt of the Arabian Plate (Late Cenomanian, northern Israel)

The paleo-depositional hinge-belt of the Levant is a zone of rapid proximal-to-distal carbonate facies transitions that defined the western edge of the passive Mesozoic Levant Margin of the Arabian Plate. It was striking parallel to the present day Mediterranean coastline, from northern Sinai to northern Lebanon, but in the mid-Cretaceous a “gap zone”, in which the facies transitions are unclear, extended from northern Israel to southern Mt. Lebanon. This study examines the paleo-physiography and sedimentary evolution in this “gap zone” in the Late Cenomanian of northern Israel. The sedimentary evolution in this region is reflected by five genetic–stratigraphic units representing systems tracts, which were proximal in the Galilee region to the north and distal to the SSW in the Carmel region. During the early Late Cenomanian a carbonate ramp sloped gently from the Galilee towards the Carmel region. Later in the Cenomanian the Galilean part of the ramp was strongly uplifted and faulting enhanced the topography of this region. A steep SSW-facing slope was formed in the Galilee, subdivided into extensional basins tens to hundreds of meters in length. Carbonate sand filled these small basins and was mass-transported further downslope, forming sheeted calciturbidites to the south in the Carmel region. This depositional phase terminated in sea-level fall and subaerial exposure. During the latest Cenomanian, faulting was renewed in the Galilee region, muddy carbonate was deposited on the slope and shelf, and debrites and slides were mass-transported downslope as far as the Carmel region. This depositional phase ended by a second episode of subaerial exposure that was followed by Early Turonian sea-level rise. The direction of mass transport in this region and the trend of proximal-to-distal facies transitions, as well as the strike of the Cenomanian faults, indicate that the depositional strike of the Levantine hinge-belt shifted in this region toward the east, departing markedly from the general NNE–SSW Levantine trend.

Constraining sediment transport to deep marine basins through submarine channels: The Levant margin in the Late Cenozoic

The recent world-class gas discoveries in Early Miocene sand units offshore Israel raises the question of their origin. Apparently, the simplest explanation is to relate them to a fluvial system that arrived from Arabia at that time. This system predated the modern (Pliocene) Nile River supply and existed until captured by the Dead Sea valley. Interestingly, however, very little sedimentation occurred along the Levant continental margin before the Pliocene in spite of its stepped structure that provided much space for accommodation. The only way that sediments could have bypassed the continental margin and arrive at the deep basin without being trapped in the middle is through submarine channels that crossed the continental margin. Here we explore this possibility using 3-D stratigraphic modeling techniques that quantify the sediment load and the water discharge required to fill the basin by pushing enough sediment through submarine channels. We show that such a scenario requires a fluvial system in the order of the largest rivers that exist today on earth in terms of drainage area and water discharge. Alternatively, it requires extreme hydraulic conditions in terms of diffusion coefficients and an elevated drainage basin that could not have existed in the study area. We therefore challenge the traditional view of Arabia as the main source for Oligo-Miocene deposits in the Levant Basin and suggest that the basin was mainly fed by a proto-Nile system that transported clastic material to the North African margin and then farther east by ocean currents. In a wider view we demonstrate how numerical modeling can constrain sediment transport through submarine channels as a function of basin geometry and hydraulic conditions, and how paleogeographic knowledge can be combined with current data on world rivers to evaluate if modeling results are plausible.

THE PERMIAN-TRIASSIC TRANSITION IN THE CENTRAL COASTAL PLAIN OF ISRAEL (NORTH ARABIAN PLATE MARGIN), DAVID 1 BOREHOLE

A succession that includes the Permian–Triassic transition was penetrated in the David 1 Borehole (Israel), located on the Levant margin sector of the northwestern Gondwanan plate. This is a fully marine section with a complex depositional interplay of distal siliciclastic and ramp carbonate sediment. Foraminifera distribution, sedimentary microfacies, δ13C excursions and e-log (gamma-ray; resistivity) data were analyzed. The local P-T boundary is placed at the first appearance of Triassic taxa, but there is a 90 m interval of overlapping faunas where the Permian taxa are small species atypical of the underlying Permian strata, and some specimens are clearly reworked. Carbonate strata were deposited in mid- to outer-ramp environments under varying conditions of sea level, storm regime, and siliciclastic (mostly silty) influx. Sea level, tracked by facies shifts, follows a low-order cyclic pattern. Two higher orders of cyclicity are also present: a short-term oscillation in storm frequency in the local depositional basin and a high-order mode in which clastic supply alternates with clastic-free carbonates, interpreted as reflecting humid-arid climate shifts of a remote, continental source region. The last mode lies within the Milankovich band of frequencies. Negative δ13C excursions, glauconite, and pyrite-rich horizons indicate hypoxic or anoxic conditions and reflect perturbations of the global carbon system in the oceans during this time. Although lithification of the latest Permian carbonates in the transitional interval was suppressed, the state of preservation of the carbonate components is not indicative of deposition under conditions of oceanic acidification.

Tectono-stratigraphic evolution of the northern Levant Basin (offshore Lebanon)

Seismic interpretation constrained by a detailed assessment of the Levant paleogeography allowed subdividing the sedimentary infill of the northern Levant Basin (offshore Lebanon) in eight major seismic packages. Fifteen seismic facies have been identified with distinctive characteristics. The Levant Basin architecture is pre-determined by a Late Paleozoic/Early Mesozoic rift that led to the formation of a passive margin. Dominant aggrading carbonate platforms are observed along the Levant margin and deepwater mixed-settings (i.e., carbonates and siliciclastics) are suggested to prevail in the basin. The collision of Afro-Arabia with Eurasia led to the development of a flexural basin in the northernmost offshore Lebanon since the Late Cretaceous. A southward migration of this flexural depocenter in the Miocene is hindered by the change in the stress field along the Latakia Ridge and by the westward escape of the Anatolian Plate in Late Miocene and Pliocene times. Interplay between major geodynamic events as well as sea level fluctuations in the Mesozoic and Cenozoic induced important marginal uplifts and emersion. Sediments sourced from the erosion of Nubian siliciclastic material and from the exposed granitic Red Sea rift shoulders and Arabian Shield, were driven into the Levant Basin. The sediment sources diversity, the mechanisms of sediment transport through varied pathways (i.e., the Levant margin canyons, the Latakia region and the Nile Delta deep-sea cone) are expected to strongly impact the reservoir characteristics and prospectivity of the northern Levant Basin.

Sedimentological and stratigraphic evolution of northern Lebanon since the Late Cretaceous: implications for the Levant margin and basin

This paper presents an updated review of the Upper Mesozoic and Cenozoic sedimentological and stratigraphic evolution of the Levant margin with a focus on the northern Lebanon. Facies and microfacies analysis of outcrop sections and onshore well cores (i.e., Kousba and Chekka) supported by nannofossil and planktonic foraminifers biostratigraphy, allowed to constrain the depositional environments prevailing in the Turonian to Late Miocene. The “Senonian” (a historical term used to define the Coniacian to Maastrichtian) source rock interval was subdivided into four sub-units with related outer-shelfal facies: (1) Upper Santonian, (2) Lower, (3) Upper Campanian, and (4) Lower Maastrichtian. This Upper Cretaceous rock unit marks the major drowning of the former Turonian rudist platform. This paper confirms the Late Lutetian to Late Burdigalian hiatus, which appears to be a direct consequence of major geodynamic events affecting the Levant region (i.e., the continued collision of Afro-Arabia with Eurasia), potentially enhanced by regressional cycles (e.g., Rupelian lowstand). The distribution of Late Burdigalian–Serravallian rhodalgal banks identified in northern Lebanon was controlled by pre-existing structures inherited from the pulsating onshore deformation. Reef barriers facies occur around the Qalhat anticline, separating an eastern, restricted back-reef setting from a western, coastal to open marine one. The acme of Mount Lebanon’s uplift and exposure is dated back to the Middle–Late Miocene; it led to important erosion of carbonates that were subsequently deposited in paleo-topographic lows. The Late Cretaceous to Cenozoic facies variations and hiatuses show that the northern Lebanon was in a higher structural position compared to the south since at least the Late Cretaceous.

Carnian (Triassic) aridization on the Levant margin: evidence from the M1 member, Mohilla Formation, Makhtesh Ramon, south Israel

The Carnian Pluvial Event was followed by extreme aridity around the Mediterranean region, but the relationship between these climatic modes and the evaporite deposits of the north Arabian margin has not been established. The Mohilla Formation in Israel was deposited on the rifted Levant margin of the Neotethyan seaway during the Carnian (Late Triassic). The lowermost member, M1 (carbonate, shale, minor evaporite), records sea-level and climate change of the transition from open-marine deposits to the thick evaporite of the overlying M2 member. Field, petrographic and cathodoluminescence investigation of the M1 member exposed at Makhtesh Ramon, southern Israel, enabled tracking of changing paleoenvironments. The M1 member can be subdivided into six sea-level controlled sedimentary cycles, each terminating in subaerial exposure. Open-marine, lagoonal, and supratidal belts are represented, but environments become increasingly restricted upwards. Three of the exposure horizons are marked by well-developed early diagenetic features, including dissolution porosity and meteoric cements. These changing facies belts and the superposed diagenetic modes formed under an oscillating climate regime of three relatively humid episodes dominated by deposition of carbonate, alternating with evaporitic sediments indicating aridity. Deposition of the M1 member can be correlated with the transition in the western Tethys from the Carnian pluvial episode to aridity. This transition in the Levant region is characterized by an oscillatory climate that culminated in a thick evaporite unit from the extreme arid phase. The oscillations may be attributed to shifting global climate belts, overprinted by monsoonal strengthening and weakening, in the equatorial belt.

Lithofacies and cyclicity of Mohilla evaporite basins on the rifted margin of the Levant in the Late Triassic, Makhtesh Ramon, southern Israel

AbstractMarine‐connected basins with evaporites occur beneath most extensional continental margins that originated at low‐latitudes and often are of major economic significance. Cyclicity in the evaporite lithofacies reflects the degree of restriction of the basin, overprinted by sea‐level changes, and caused by structural movements in the barrier region, whether by fault‐block rotation, footwall uplift or hanging wall subsidence, in both extensional and compressional basins. The Upper Triassic evaporites of the Ramon section in southern Israel model cyclic sedimentation in such environments. The Mohilla Formation is a carbonate–evaporate–siliciclastic succession of Carnian age that fills a chain of basins extending along the Levant margin from southern Israel to Jordan and Syria. The basins developed in half‐grabens adjacent to normal faults that formed during a period of regional extension. Evaporites of this formation are well‐exposed in outcrops at Makhtesh Ramon, the southernmost of these basins. The M2 Member of the Mohilla Formation is composed of 42 sub‐metre cycles of alternating dolostone, gypsum and calcareous shales. Field and microfacies analysis showed these cycles to conform mostly to restricted shallow and marginal marine environments, spatially limited by the uplifted shoulders of the half‐graben systems. A total of 10 facies types belonging to six depositional environments have been identified. From stacking patterns and analysis of bed to bed change, cycles can be categorized into three groupings: (i) low frequency exposure to exposure cycles that developed under eustatic or climate control; (ii) high frequency deepening/shallowing‐upward cycles, characterized by gradual transitions due to short‐term sea‐level or runoff‐event oscillations possibly referable to orbital forcing; and (iii) high frequency shallowing‐upward cycles, characterized by abrupt transitions, attributable to sporadic tectonic events affecting accommodation space or barrier effectiveness. The way facies and cycling of the sedimentary environments was deciphered in the Mohilla evaporite basin can be used to unravel the genesis of many other evaporite basins with barriers of tectonic origin.

Inland jump of the Arabian northwest plate boundary from the Levant continental margin to the Dead Sea Transform

While the breakup of Arabia and Africa began in the early Oligocene, the northwestern boundary of the Arabian Plate along the Dead Sea Transform (DST) formed 10–15 Myr later (early–middle Miocene). During the early stage of breakup the Red Sea Rift continued propagating northwestward, forming the Suez Rift. The present ∼45° northward twist of the plate boundary from the Red Sea toward the Gulf of Eilat (Aqaba) still did not exist. What happened at the northern tip of the Suez Rift at that time? How was strain distributed to its surroundings, and where did the plate boundary continue from there? Here we describe an abandoned segment of the Arabian northwestern plate boundary that extended from the northern tip of the Suez Rift northeastward, along the Levant margin. Seismic data collected offshore Israel support a subsurface, deep‐rooted fault zone running along the base of the continental slope. These faults indicate Oligocene transpressional lateral shearing. We propose that during the early stage of continental breakup a left‐lateral strike‐slip motion of ∼10 km took place along this embryonic plate boundary. Such deep‐rooted tectonism implies that unlike the passive situation of the Israel‐Sinai continental margin witnessed presently and before the Oligocene, during the early stage of the Africa‐Arabia breakup this part of the continental margin was reactivated. We further suggest that the inland jump of the plate boundary toward the DST was not immediate and that during the transitional period the Israel‐Sinai triangular block was an independent subplate with deformation all around it.

Strain partitioning in gravity-driven shortening of a thick, multilayered evaporite sequence

Abstract Three-dimensional seismic data from the Levant Basin, eastern Mediterranean, was used to quantify longitudinal strains in thick, multilayered Messinian evaporites at an early stage of salt tectonics. Gravity-spreading is driven by basin subsidence and tilting of the Levant margin and by progradation of the Nile Cone. Similar styles of shortening in two separate 3D survey areas comprise detachment folds, thrust-ramp folds and conjugate arrays of strike-slip faults. These Pleistocene structures can be explained with a single deformation phase with a tectonic transport direction of NE to ENE, obliquely opposed to the extension updip, which began in the Late Pliocene. Four major detachments within the Messinian are probably halite-rich intervals in the multilayer. Shortening of competent interlayers varies from 1–2% near the base to c. 7% near the top of the Messinian, with a sharp reduction in shortening at the top Messinian and roof to 1–2%. This shortening profile is attributed to asymmetric Poiseuille flow, indicating that salt is flowing downdip faster than the overburden is translating. Physical modelling supports the inferred flow profile, showing that each mobile layer flows faster than adjoining competent layers and that strains in evaporites can be far greater than in the overburden. This is the first published use of seismic data to demonstrate the flow regime within salt on a regional scale.

Stratigraphic evidence for shear in structural development of the Triassic Levant margin: New borehole data on the epicontinental to deep marine transition in Israel

Triassic tectonic movements that include shear along a significant portion of the Levant margin, are evidenced from microfacies analysis of material recovered from the Asher-Atlit 1, Ga'ash-2, Meged-2, Devora-2 and Ramalla-1 onshore boreholes.Seismic studies showed that structural lineaments attributed to early Mesozoic extension underlie coastal and central Israel, trending NE-SW beneath southern Israel and sub-parallel to the then- extensional Palmyride basin of Syria. A more curved trend, approximately NNW–SSE, lies to the north beneath central Israel. Coast-parallel sedimentary domains formed above these lineaments, which constitute the newly formed passive margin of the Levant coast in the Triassic. The sedimentary history of these domains indicates that some were linked to each other, and others disconnected. The relative vertical movement between one domain and another is explained by activation of transpressional and trans-tensional shear movements on the underlying curved faults. These subordinate vertical movements also created the discontinuous barriers and small subsiding basins that separate the epicontinental sedimentary domain from the open Tethys, causing partial restriction necessary for the intermittent development of thick evaporites in the internal domains, alternating with a regionally suppressed carbonate system. This zone is here named the Onshore Levant Margin Shear Zone (OLMSZ).Shear was invoked theoretically in a number of models for the tectonic evolution of the eastern Mediterranean as part of a Neotethyan opening system. This paper provides rock-based evidence for such shear applicable to 20% of the eastern Levant margin in the Triassic.

The sequence stratigraphy of Mesozoic successions in the Levant margin, southwestern Israel: A model for the evolution of southern Tethys margins

The Levant margin, in the subsurface of the eastern Mediterranean area, formed during the early Mesozoic following rifting and subsequent opening of the southern Tethys Ocean. This work describes the stratigraphic evolution of the shelf edge and slope for this margin in southwestern Israel and in the adjacent Mediterranean Sea. The study is based on the interpretation of 27 wells and 92 seismic reflection lines totaling 2000 km (1243 mi). Depositional sequences and sequence boundaries of the Jurassic and the Cretaceous age inferred from seismic reflection terminations, wireline-log stacking patterns, lithofacies, and biostratigraphic data. Six low-order and 22 high-order depositional cycles were identified. Their stratigraphic architecture reflects shifts of depocenters from the basin to its margin, controlled by eustasy and regional subsidence. Aggrading and backstepping of carbonate platforms in the Levant shelf is associated with relative rises in sea level. Progradation of siliciclastic and carbonate slopes toward the basin is related to relative drops in sea level. The stratigraphic framework of the Levant margin presented here is in accordance with recently published Mesozoic sequence stratigraphy of the Arabian platform, therefore, it may be used as a working model for reconstructing other rifted Tethyan margins in the region. This study further emphasizes the reservoir potential of Jurassic and Cretaceous deep-water lowstand wedges offshore Israel, where extensive exploration efforts are currently occurring.

Calcareous nannofossil assemblage changes from early to middle Eocene in the Levant margin of the Tethys, central Israel

Abstract. Patterns of change in calcareous nannofossil assemblages during nannozones NP11 to NP16 on the southern Levant margin of the Tethys were observed from sections of early and middle Eocene age sediments of the Avedat Plateau, central Israel. A cooling process following the Early Eocene Climate Optimum (EECO) is supported by several events of biotic change over a 4 Ma interval. The rate of pelagic sedimentation varied from 7.5 at the EECO to 23.6 m Ma–1 at the cooling transition phase. Reduced numbers of discoasters mark the end of the oligotrophic regime within the NP13 nannozone, followed by an increase in nannofossil richness especially marked by Blackites and Chiasmolithus spp. In the middle part of the cooling process a prominent peak of reworked Paleocene taxa, up to 7% of total taxa, suggests that enhanced current activity caused re-sedimentation on the Levant margin slopes. When stability resumed in the upper part of the NP15–16 interval, Coccolithus-type placoliths became rare and Reticulofenestra-type forms became dominant. Calcareous nannoplankton response to this gradual cooling became irreversible in the late Palaeogene, but the change was, however, diachronous across the Tethys.

Platform to shelf edge transect, Triassic of northern Israel, North Arabian Plate

A transect of the Middle to Late Triassic from the epicontinental belt to the shelf edge of the north Arabian margin is presented, based on new data from two boreholes in northern Israel. Two sedimentary systems are encountered along this traverse: the inland Meged-2 borehole represents the seaward extension of the epicontinental belt, with shallow- to deep-water carbonates, salina evaporites, and basinal shales, while Ga'ash-2, on the Levant margin, was positioned on an isolated platform separating the internal shelf-basin system from the open Tethys, displaying a shallower range of facies that is free of evaporites. Proximal-distal facies shifts are bundled into five low-order (LO) T–R cycles, ranging from Anisian (Pelsonian) to Norian, each composed of numerous high-order (HO) shallowing-upwards cycles. Meged-2 paleoenvironments imply an interior basin trapping sediments of the epicontinental belt, with numerous HO facies shifts indicating pulses of subsidence. Ga'ash-2 contains Lofer-like peritidal cycles and a late Anisian — early Carnian hiatus in place of the second LO cycle. The two orders of cycling are controlled by extrabasinal regional or eustatic change, and synsedimentary vertical movements. The divergent sedimentary patterns of the late Anisian–late Carnian can be attributed to NW–SE trans-tensile movements impacting on earlier Neotethyan extensional trends. Synsedimentary movements, represented locally by uplift at Ga'ash-2 and subsidence at Meged-2, controlled the influx of sea water into the epicontinental zone, and consequently, controlled the alternation of evaporite vs. carbonate systems. In the latest Carnian–early Norian, these facies belts become locked together forming a shallow, high energy shelf. This change reflects broad uplift and shifting of the locus of active differential movement into the Levant Basin.

Middle–Late Eocene structure of the southern Levant continental margin — Tectonic motion versus global sea-level change

During the Paleogene greenhouse episode Earth experienced the warmest period of the Cenozoic while global sea level rose by more than 100 m. However, geological evidence from the Levant margin, northwestern Arabian plate, indicates that throughout this period seabed deepening exceeded 1000 m. Lithology from Israel, Syria, Lebanon and Jordan is mainly pelagic and neritic, interfered by occasional fossil sub-marine slumps. In order to understand this dissimilarity we quantify the vertical tectonic motion of the Levant continental margin through the Paleogene. The margin began to take shape during the Late Permian and it was reactivated during the Oligocene. Based on information from outcrops, drillholes, seismic reflection and refraction, gravity, and previous publications, a multi-layered model of the Levant lithosphere was established. Layers include the Moho, top of the crystalline basement and covering sediments up to the Late Eocene. The model was restored horizontally by 100 km along the younger Dead Sea transform. Assuming local isostatic compensation, vertical restoration yielded the paleo-bathymetry which prevailed across northwestern Arabia during the Middle–Late Eocene. Results show that following the margin subsidence the Cretaceous Levantine platform became ramp shaped during the Eocene. Most parts of the central Levant were submerged under ~ 200 to ~ 1800 m of water, while the paleo-bathymetric gradients ranged from ~ 2° at the shelf to ~ 6° at the slope. The apparent dissimilarity between sea level and our tectonic-based calculations is up to an order of magnitude. These differences may be resolved by accounting for vertical tectonic motions and sediment supply rates. Our results stress the importance of the presented crustal structure. As opposed to the backstripping procedure, the structural map of the top Eocene interface was constructed upwards from the well established top Turonian (Judea Group) interface since only scarce and sporadic outcrops of the target horizon are available. We suggest that a similar approach should be applied to re-evaluate the depositional environments across the entire continental margin of the eastern Mediterranean, an area with proven hydrocarbon prospects.

Tectonic evolution of the southern Levant margin since Mesozoic

Recognition of syndepositional faults and mechanical analysis of fault-slip data are used to reconstruct a high resolution tectonic evolution of Israel, and to characterize the stress fields associated with the major tectonic deformation events of this area since Mesozoic times. Syndepositional normal faults recognized in Mesozoic and Paleogene rocks indicate three extensive deformation phases that were active at least during Early Jurassic, Campanian, and Eocene times. Inversion of fault-slip data indicate that a NE–SW extension characterizes the two first events, whereas orientation of extension during the Eocene was N–S to NNE–SSW. Several scenarios are proposed to explain these newly documented normal faults. Measured faults also document synchronous strike-slip and reverse regimes. Unambiguous chronological relationships between fault-data and bedding attest that a WNW–ESE to NW–SE compression is associated with the Syrian Arc folding event during the Late Cretaceous times. This compression pursued during the development of the Dead Sea transform plate boundary but its relationship with Neogene structures is unclear. Fault-data suggest that folding during the Neogene was driven by a regional NNW–SSE compression. A minor NE–SW compression was also recognized but no compatible large-scale structures were found to date. We also show that the post-Pliocene normal faults developed under a NE–SW extension.

Effects of Cretaceous plume and convergence, and Early Tertiary tectonomagmatic quiescence on the central and southern Levant continental margin

Abstract: This study synthesizes geological and geophysical evidence concerning the structure and character of the central and southern Jurassic Levant continental margin during Cretaceous–Tertiary time. From the beginning of the Cretaceous and until Cenomanian time, the Levant margin was strongly affected by extensional tectonics, cyclical igneous activity and rifting coupled with thermal and vertical fluctuations. It is suggested here that during the Senonian–Maastrichtian convergence of Afro-Arabia and the Mesotethys, and the Tauride part of Eurasia, the Herodotus basin oceanic crust subducted along the Eratosthenes Arc, below the short-lived abandoned Levant back-arc basin. Such a plate configuration assumes regional shear zones, as follows: (1) between the Eratosthenes Arc from the south and the Kyrenia Arc from the north: the NW–SE Carmel–Azraq–Sirhan fault system; (2) between the Sinai and the African plates: the Suez fault system; (3) between the Mesotethys and the African plates: the northern Egypt–Sinai–Negev west–east transversal fault system. Distinct tectonomagmatic quiescence between Late Maastrichtian and Late Eocene time allowed thermal relaxation and subsidence of the Levant margin until the apparent achievement of local isostatic compensation and the consequent development of the longest transgression over the Afro-Arabian ramp. Supplementary material: Details on the construction of the Bouguer gravity map are available at http://www.geolsoc.org.uk/SUP18404 .