geology and structure of the continental margin off northern israel and the adjacent part of the levantine basin abstract the continental margin off northern israel and southern lebanon is characterized by a narrow coastal plain in places it is absent a narrow shelf a narrow slope which is incised by numerous submarine canyons and by a complex topography of the adjacent deep sea levantine platform detailed seismic reflection surveys have revealed the development of the area since the late miocene during the messinian when the level of the mediterranean sea dropped the present continental slope area was exposed eroded and covered by thinly scattered sediments in the deep basin evaporite bearing series accumulated reaching 1 km in thickness about 60 km offshore during the pliocene quaternary the area was covered by a fine clastic sequence up to 1 5 km thick that forms the present continental margin basinward gravitational slumping of these sediments over the messinian evaporites which acted as a lubricant resulted in a complex topography and many shore parallel rootless growth faults along the base of the continental slope and the adjacent deep sea young faults which are exposed in northern israel and extend seaward comprise the most important structural feature of the study area these faults were active during the pliocene and quaternary possibly also during the miocene the major nw trending young yagur carmel fault and e w trending rosh hanniqra fault extend to the base of the continental slope where they converge enclosing the complex western galilee graben the relief of the base of the pliocene quaternary sequence was affected by motions of these faults and of smaller faults inside the graben farther seaward a horst like block is developed along the extension of the carmel fault still farther basinward there is a group of diapiric ridges trending nw to e w they were formed by flowage of messinian evaporites in some cases these ridges seem to be aligned along underlying faults this group of diapirs is unique in the area the diapir ridges are interpreted as expressions of deeply rooted faults

the origin of the dead sea rift abstract the dead sea rift is considered to be a plate boundary of the transform type several key questions regarding its structure and evolution are does sea floor spreading activity propagate from the red sea into the dead sea rift did rifting activity start simultaneously along the entire length of the dead sea rift or did it propagate from several centres why did the initial propagation of the red sea into the gulf of suez stop and an opening of the gulf of elat start using crustal structure data from north africa and the eastern mediterranean and approximating the deformation of the lithosphere by a deformation of a multilayer thin sheet that overlies an inviscid half space the regional stress field in this region was calculated using this approach it is possible to take into account variations of lithospheric thickness and the transition from a continental to an oceanic crust by application of a strain dependent visco elastic model of a solid with damage it is possible to describe the process of creation and evolution of narrow zones of strain rate localization corresponding to the high value of the damage parameter i e fault zones mathematical simulation of the plate motion and faulting process suggests that the dead sea rift was created as a result of a simultaneous propagation of two different transforms one propagated from the red sea through the gulf of elat to the north the other transform started at the collision zone in turkey and propagated to the south

mesozoic volcanism in the middle east geochemical isotopic and petrogenetic evolution of extension related alkali basalts from central lebanon mesozoic picritic and alkali basalts from central lebanon represent a significant part of an extension related upper jurassic to upper cretaceous discontinuous volcanic belt which occurs throughout the middle east volcanism was associated with an episode of intraplate extension that followed a period of continental break up where mesozoic micro continental blocks separated from gondwana as the neotethys ocean opened in jurassic times this volcanic episode produced mafic lava flows ranging in thickness from 5 to 20 m along with some minor pyroclastic flows these flows are stratigraphically intercalated with thick carbonate platform deposits the basalts are made up of about 15 20 olivine fo 78 91 30 35 clinopyroxene salite 40 50 plagioclase an 56 71 and opaque fe ti oxides 5 geochemically the rocks exhibit a relatively wide range of sio 2 40 4 to 50 5 wt and mgo 5 1 to 15 5 wt contents are relatively enriched in tio 2 1 7 to 3 7 wt and vary in composition from alkali picrite and basanite to alkali basalt the mg numbers range from 0 56 to 0 70 with an average of 0 63 the rocks are enriched in incompatible trace elements such as zr 86 247 ppm nb 16 66 ppm and y 19 30 ppm such compositions are typical of those of himu oib and plume related magmas the ree patterns are fractionated la yb n 11 lree enriched and are generally parallel to subparallel elemental ratios such as k p 1 1 4 7 la ta 11 13 la nb 0 57 0 70 nb y 0 68 1 55 and th nb 0 20 0 36 suggest that crustal contamination was minor or absent this may be related to a rapid ascent of the magma in agreement with the nature mafic oceanic like and the small thickness about 12 km of the mesozoic crust of the eastern mediterranean region the 143 nd 144 nd isotopic compositions of the lavas range from 0 512826 to 0 512886 and 87 sr 86 sr from 0 702971 to 0 703669 suggesting a himu like mantle source trace element compositions indicate a melt segregation depth of 100 110 km well within the garnet lherzolite stability field the geochemical characteristics of the rocks are typical of within plate alkali basalts and suggest that the magmas were derived from a fertile possibly plume related enriched mantle source petrogenetic modelling indicates that the magmas were produced by very small degrees of batch partial melting f 1 5 of a primitive garnet bearing mantle source garnet lherzolite

multiple opening and closing of the eastern mediterranean and south china basins the eastern mediterranean east of crete and the south china basin are small ocean basins surrounded by continental masses and are currently undergoing closure they were both formed by the rifting of continental fragments away from large continents a comparison of the geological evolution of the two basins indicates a remarkable similarity in the sequence of evolutionary stages that took place in both basins although the age of these stages is probably different for each of the two the formation of the two basins is a consequence of a much larger process in which large lithospheric plates south and north of the basins move toward each other africa including sinai and arabia toward eurasia and india australia toward eurasia and the pacific each basin went through several stages of evolution during which oceanic crust was created and destroyed during each stage the area of the newly formed oceanic crust was smaller than the area formed in the previous stage it appears as if similar evolutionary patterns also occurred in other marginal and small ocean basins formed by continental rifting

permian early mesozoic tectonism and continental margin formation in israel and its implications for the history of the eastern mediterranean summary the early mesozoic tectonic reorganization of the tethys region also affected the levant area here two processes were superimposed a the pattern of long wavelength vertical motions of the arabo nubian platform changed in the late permian when israel and nearby areas began to subside b rifting occurred in this subsiding area probably in several phases late anisian and ladinian carnian norian and liassic differential movements reached 2 3 km and magmatism occurred in the liassic and perhaps also in the triassic the tectonism was strongly felt up to 50 km landward of the present coast the crust was thinned and modified under the present continental margin and in the main rifts passive margin conditions were established in late liassic times over the previously faulted area later in the jurassic a carbonate shelf was constructed along this subsiding margin its basinward edge was 1 1 5 km high which shows that the adjacent se mediterranean was already a deep sea hence this basin and its passive margin are considered to have been shaped by the early mesozoic rifting which is recognized in israel the rifting process probably signifies oblique separation of the tauride block from the levant part of gondwana

intraplate rotational deformation induced by faults vertical axis rotations provide important constraints on the tectonic history of plate boundaries geodetic measurements can be used to calculate interseismic rotations whereas paleomagnetic remanence directions provide constraints on the long term rotations accumulated over geological timescales here we present a new mechanical modeling approach that links between intraplate deformational patterns of these timescales we construct mechanical models of active faults at their locked state to simulate the presumed to be elastic interseismic deformation rate observed by gps measurements we then apply a slip to the faults above the locking depth to simulate the long term deformation of the crust from which we derive the accumulated rotations we test this approach in northern israel along the dead sea fault and carmel gilboa fault system we use 12 years of interseismic gps measurements to constrain a slip model of the major faults found in this region next we compare the modeled rotations against long term rotations determined based on new primary magnetic remanence directions from 29 sites with known age the distributional pattern of site mean declinations is in general agreement with the vertical axis rotations predicted by the mechanical model both showing anomalously high rotations near fault tips and bending points overall the results from northern israel validate the effectiveness of our approach and indicate that rotations induced by motion along faults may act in parallel or alone to rigid block rotations finally the new suggested method unravels important insights on the evolution timing magnitude and style of deformation along major faults

late tertiary paleodepth reconstruction of the levant margin off israel abstract paleodepth reconstructions of the late tertiary levant continental margin off israel using one and two dimensional quantitative basin analysis reveals several interesting phenomena in the evolution of the margin such as tilting events of the deep basin in north south and east west directions westward progradation of the continental shelf in the southern levant and the variation in style along the levant margin this variation may be the result from the decreasing influence of the nile to the north and the increasing influence of the nearby plate boundaries in general the bathymetry of the margin from the deep basin to the base of the slope has become shallower since base neogene this reflects the general filling of the eastern mediterranean at a time when the sediment supply from the continental margin exceeds the subsidence the paleodepth reconstruction also suggests the existence of a deep basin in pre messinian time which resembles the present one thus implying that the deposition of the evaporites during the messinian desiccation of the mediterranean sea occurred in a deep basin

weak motion based attenuation relationships for israel summary we performed a regional study of earthquake ground motion scaling relations to provide the seismic hazard community of israel with a new attenuation relationship that could be used for the prediction of earthquake induced ground motion strong earthquakes are rather scarce in israel and the existing collection of records from strong earthquakes is not sufficient to allow the use of traditional regression methods to develop a regional attenuation relationship we used velocity seismograms from the israel seismic network to estimate the distance and frequency dependence of ground motion in the israel region from frequent smaller regional earthquakes our analyses included 4814 waveforms recorded by 30 stations of the israel seismic network from 2000 to 2005 we restricted our analysis to 330 events recorded at five or more stations with duration magnitudes ranging between 1 0 and 5 2 we derived empirical excitation site and regional attenuation terms by regressing the peak amplitudes of narrowband filtered seismograms around the shear wave arrivals and the rms fourier spectral amplitudes taken around the specific sampling frequency in order to optimize the attenuation parameters in our scaling model we used a simple grid search an optimal solution for minimal error between empirical and theoretical attenuation function was found for the quality parameter q f 298f0 67 and the geometrical spreading g r parametrized as a bilinear piecewise function r 0 74 for r 60 km and r 0 47 for r 60 km the spectral parameters of 0 015 s and stress drop increasing from 0 3 to 4 mpa were used to model the excitation spectra a theoretical modelling effort based on brune s source spectrum and random vibration theory rvt was performed on the attenuation and source parameters estimated in this study comparison of the attenuation relationship derived with locally measured ground motions shows excellent agreement with the data in the magnitude range for which we have observations and seems to be adequate for predictions of earthquake ground motion for the israel region comparison of peak ground acceleration pga predictions based on our scaling relationship with those that have been recently used for seismic hazard analysis in israel shows that our attenuation relationship predicts significantly lower ground motions than other relations

magnetic susceptibility evolution and sedimentary environments on carbonate platform sediments and atolls comparison of the frasnian from belgium and alberta canada article i nfo magnetic susceptibility ms measurements on carbonate rocks are considered as a proxy for impurities delivered to the carbonate environments in the absence of strong climatic or tectonic variations bulk ms values have been linked to sea level variations because sea level fall increases clastic supply and therefore increases in magnetic mineral deposition in this paper we explore the relationship between the average magnitude of bulk ms with shallowing up sequences and facies evolution in different devonian carbonate complexes similarities and differences between these parameters have been scrutinized in carbonate attached platform and detached platforms mounds and or atolls from belgium and canada in the carbonate attached platforms from belgium and canada the ms patterns are directly related to depositional environment mean ms values increase from the most distal towards the most proximal facies and towards the top of the majority of fourth order shallowing up sequences these trends are in agreement with theoretical background ms increases with regression

development of the palaeogeography of pangaea from late carboniferous to early permian abstract old and new well and poorly known lithofacies data of moscovian and artinskian age in the area limited by the arctic sea and central africa the atlantic ocean and the ural mountains have been plotted on present day maps the facies mapped and related environments allow the recognition of a series of different palaeogeographic palaeotectonic units including the late carboniferous to early permian deep sea to palaeo tethyan ocean west siberia kazakhstan continent and uralian kazakhstan tienshan arc uralian foredeep up to the closing arms of the uralian ocean precaspian basin russian platform donets rift basin caucasian moesian dobrogean polish oslo basinal belt syn tectonic hercynian foreland basin intramontane post hercynian basins iran anatolian hellenic dinaric carnic basin branching into the hungarian seaway apennine basin branching into the cantabrian and south portuguese basins oman iraq levantine sicily deep basin and inferred oceanic sea way south peri tethyan platform basins east arabian cratonic basin and north african intracratonic basins the subsidence sedimentation trends of these units were correlated and compared through lithostratigraphic logs bathymetric curves and uncorrected cumulative stratigraphic curves the sets of original and processed data were used to test two different palaeodynamic models a pangaea a model static from late carboniferous to triassic and a mobile pangaea b model with different dextral displacements between laurussia and gondwanaland in the same time interval the best fit for our data requires a strike slip offset of about 800 km from moscovian to artinskian time this model implies a first quasi pangaea or pangaea b assembly at the carboniferous permian transition an ephemeral pangaea b break up driven by an early permian oblique rift across the mediterranean to caribbean areas and a final pangaea a assembly in the mid to late permian the two palinspastic maps describing the model have been cross checked by comparison with an independent set of biogeographic features of late carboniferous and early permian overall floral reptile and marine benthic organism distribution is consistent with the early permian trans pangaea seaway inferred from facies and palaeodynamic analyses

curie depth map for sinai peninsula egypt deduced from the analysis of magnetic data abstract sinai peninsula is considered as a unique region in the world due to its geographical location tectonic and thermal activities it is located geographically at the crossroads of europe asia and africa constituting a triple junction point between the three continents it is also characterized by thermal manifestations represented by several hot springs with varied temperatures 30 70 c most of these hot springs are located along the shoreline of the gulf of suez in this study we aim to map the curie depth isotherm surface for sinai peninsula based on the analysis of ground magnetic data spectral analysis technique will be used to estimate the boundaries top and bottom of the magnetized crust the depths obtained for the bottom of magnetized crust are assumed to correspond to curie point depths where the magnetic layer loss its magnetization results of this study indicate that the shallow curie depths 15 18 km are located at the southern part of sinai peninsula and along the shoreline of the gulf of suez and depths increase 22 25 km towards the central and north western portions of sinai peninsula the whole average curie depth point of sinai peninsula is about 20 km generally the shallow depths to curie isotherm indicate that sinai peninsula is a promising area for further geothermal exploration particularly near the eastern side of the gulf of suez

origin and role of major strike slip transfers during plate collision in the central mediterranean variations in the crustal structure along the northern african plate margin have caused different modes of collision with eurasia lateral density variations along the central mediterranean collision zone are expressed in a change of the angle of the downbending african plate and lead to the formation of strike slip transfers in these transition zones that are roughly perpendicular to the trend of the collisional zone in some cases these transfer zones are developed into hinge faults while in others they can be developed into transform faults this process governs the segmentation of the collision zone in the central mediterranean region south of the maghrebian thrust belt in tunisia and sicily through the calabrian arc to the northeastern hellenic arc extending further to the cyprian arc and to the taurus zagros chain

seismotectonics of the sinai subplate the eastern mediterranean region summary we define the sinai subplate from a seismotectonic perspective as a distinct component in the plate tectonics of the eastern mediterranean region this is based on the tectonic characteristics of a comprehensive listing of all ml 4 recorded seismicity in the region during the 20th century on newly calculated and recalculated fault plane mechanisms of first p wave arrivals and on published solutions based on waveform inversion of broad band data the low seismicity level and scarcity of strong events in the region required a thorough search for useful data and a careful examination of the reliability of the focal solutions we gathered all available records of first p wave onsets from the iss and isc bulletins and the local seismic networks altogether we were able to calculate 48 new focal mechanisms and 33 recalculated ones of events that occurred during the years 1940 1992 with the increasing number of teleseismic and regional broad band stations in the later years we added 37 solutions based on teleseismic and regional waveform inversions of events that occurred during 1977 2001 these mechanisms enabled us to examine the seismotectonic character of the sinai subplate the strike and rake directions of the calculated mechanisms usually reflect the geometry and the large scale type of deformation observed along the boundaries of the sinai subplate the dead sea transform the cypriot arc convergent zone and the suez rift nevertheless along each of these boundaries we found anomalous solutions that attest to the complexity of the deformation processes along plate margins earthquakes along the dead sea transform exhibit mainly sinistral transtension and transpression reflecting its leaky manner and local change in the transform geometry the presence of other unexpected mechanisms near the transform however reflects the heterogeneous deformation it induces around as expected thrust mechanisms along the cypriot arc mirror its convergent nature and typical curved geometry transtension and transpressional solutions in the eastern segment of the arc reflect the sinistral shear motion between anatolia and sinai there however shear mechanisms found between cyprus and the eratosthenes seamount pose a problem regarding its collision process most intriguing of all are ml 4 thrust and shear solutions found in the gulf of suez they are associated with predominantly normal mechanisms within a rift zone and therefore constitute a unique phenomenon yet to be deciphered

stratigraphic evidence for shear in structural development of the triassic levant margin new borehole data on the epicontinental to deep marine transition in israel abstract 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

tectonic processes in offshore northern israel and the evolution of the carmel structure abstract the carmel structure in northern israel is an elevated tilted block that extends from the land into the continental shelf and divides the levant continental margin into two distinct provinces its axis trends at a high angle to the levant margin and deflects mesozoic and cenozoic sedimentary and basement rocks the carmel structure is probably older than the levant margin itself and has been through several phases of activity most of the multichannel seismic profiles in the offshore of northern israel were reprocessed through time migration and then interpreted the resultant maps combined with gravimetric magnetic and bathymetric maps show a complex tectonic picture of the carmel structure and its vicinity four evolutionary stages can be recognized in this area a early mesozoic rifting along the present levant margin we speculate that the carmel was at that time a triple junction a thick mesozoic volcanic and carbonatic section of more than 6500 m indicates rapid subsidence probably accompanied by normal faulting b folding along the nne axis this is probably part of the syrian arc compressional system which was active from the late cretaceous until the eocene normal faults of the previous stage were probably reactivated becoming reverse faults c left lateral strike slips faulting this formed a north west fault system which resulted in a clockwise rotation of segments of the fold axis and was active from the late miocene to early pliocene d a tensional tectonic regime prevails since the pliocene and is probably still active at present the well pronounced kishon graben which extends from land to the continental shelf was formed during this period the first two stages are of regional extent whereas the latter stages are the reslt of local modification of the regional stress fields

crustal structure variations and transcurrent faulting at the eastern and western margins of the eastern mediterranean abstract crustal structure variations within the crust of the eastern mediterranean as well as within the continental crust of the land areas east and west of the basin have caused segmentation of the collision zones which extend from sicily through the calabrian arc the hellenic arc and the cyprian arc to the taurus chain on both sides of the eastern mediterranean in southeastern sicily and in the levant similar tectonic features have developed hinge faults exist along both continental margins due to the different modes of collision between the land areas and the adjacent oceanic areas landward of the margins two large transcurrent fault systems the scicli fault zone and the dead sea rift have developed due to the existence of unique crustal units within the continental crust adjacent to the margins on both sides these units are more buoyant than the adjacent crust and resist underthrusting the initial faulting along both transcurrent fault systems probably started at the collision zone in the north and propagated to the south where large extensional areas the pantelleria rift and the red sea exist

internal structure of the dead sea leaky transform rift in relation to plate kinematics abstract the structures along the dead sea transform rift are related to the motions of the sinai and arabia plates which border it and to the irregularities of their boundaries the total slip was 105 km left lateral but the present structures were formed mainly during the last 40 km of slip which probably occurred in the plio pleistocene along the southern half of the transform the strike slip motion takes place on en echelon faults this produces rhomb shaped grabens or pull aparts which are sometimes composite and in which there is local crustal separation thus much of the transform is leaky these structures occur in a morpho tectonic rift valley delimited by normal faults which express a small component of transverse extension along a few segments the shape of the transform is such that lateral motion produces local transverse compression the geometric relations of the structures along the transform define an eulerian pole of relative plate motions at 32 8 n 22 6 e 0 5 the older motion was somewhat different and is described by a pole located about 5 west of the above then the component of transverse extension and crustal separation was much smaller than now while local transverse compression was more important the northern half of the dead sea transform has an irregular shape and the bordering plates did not remain rigid as lateral motion continued here transverse compression is often important

teleseismic traveltimes residuals across the dead sea basin new findings of the structure of the dead sea sedimentary basin and its eastern and western bordering regions are obtained by p and pkp wave relative traveltime residuals of 644 teleseisms as recorded by the dead sea integrated research portable seismic network in the dead sea basin and its neighboring regions the lisan peninsula is characterized by relatively small teleseismic traveltime residuals of about 0 14 s in the latitude range of 31 22 31 37 and at the longitude of 35 50 slowly decreasing toward the west the largest teleseismic traveltime residuals are in the southern dead sea basin south of the lisan peninsula in the latitude range of 31 05 31 15 and along longitude 35 45 and continuing southward toward the amaziahu fault reaching values of 0 4 0 5 s there is a small positive residual at the amaziahu fault and a small negative residual south of it probably marking the southern end of the dead sea basin east and west of the dead sea basin the mean teleseismic traveltime residuals are negative with overall averages of 0 35 s and 0 45 s respectively using the teleseismic residuals we estimate the horizontal dimensions of the lisan salt diapir to be 23 km 13 km at its widest and a maximal thickness of about 7 2 km the thickness of the mount sodom salt diapir is estimated as 6 2 km

crustal deformation along the dead sea transform and the carmel fault inferred from 12 years of gps measurements received 20 february 2012 revised 27 june 2012 accepted 30 june 2012 published 17 august 2012 1 large scale crustal deformation in the levant is mainly related to the dst and the cfs the former is an active left lateral transform bounding the arabian plate and the sinai sub plate and the latter branches out of the former and separates the sinai sub plate into two tectonic domains in this study we obtain the velocities of 33 permanent gps stations and 145 survey stations that were surveyed in three campaigns between 1996 and 2008 we use a simple 1 d elastic dislocation model to infer the slip rate and locking depth along various segments of the dst we infer a 3 1 4 5 mm yr slip rate and a 7 8 16 5 km locking depth along the dst north of the cfs and a slip rate of 4 6 5 9 mm yr and locking depth of 11 8 24 km along the jericho valley south of the cfs further south along the arava valley we obtain a slip rate of 4 7 5 4 mm yr and a locking depth of 12 1 23 km we identify an oblique motion along the carmel fault with 0 7 mm yr left lateral and 0 6 mm yr extension rates resulting in n s extension across the carmel fault this result together with the decrease in dst slip velocity from the jericho valley to the segment north of the cfs confirms previous suggestions according to which part of the slip between arabia and sinai is being transferred from the dst to the cfs

seismic evidence for neogene and active shortening offshore of lebanon shalimar cruise 1 lebanon located on a 160 km long transpressional bend of the left lateral levant dead sea fault system lfs has been the site of infrequent but large earthquakes including one submarine tsunamigenic event the main objective of the shalimar marine survey was to characterize and map active deformation offshore of lebanon using a range of geophysical techniques particularly seismic reflection profiling the cruise results clearly establish the presence of young submarine thrust faults and folds and clarify the structure of this part of the levant margin a submarine fold belt bounded by thrusts and lateral ramps and extending up to 30 km from the shoreline is interpreted as the foreland thrust system of the actively growing mount lebanon range there is no large fault extending into the levant basin toward cyprus which indicates that thrusting only absorbs local transpression resulting from the lebanese restraining bend both the miocene and plio quaternary sedimentary sequences are affected by shortening with landward dipping blind thrusts and associated growth strata the presence of the messinian evaporites creates complex deformation patterns including normal faults due both to folding accommodation and to gravity spreading all well imaged in the seismic reflection profiles because the evaporite layer acts as a decollement level shortening extends farther out seaward through a series of thrust imbricates or duplexes the strongest shortening observed between beirut and batroun decreases toward the south between saida and tyre north of tripoli the passive margin is not affected by neogene deformation and is well preserved we propose that since the miocene the northward propagating lfs interacted with margin structures inherited from the mesozoic rifting phase and was deviated along the more rigid oceanic crust flooring the levant basin a process which led to the formation of the lebanese restraining bend of the lfs and consequently to the offshore shortening we document here such coastal transpression has resulted in local 100 km inversion of the passive margin which might eventually evolve into a new subduction zone

transform margin of the northern levant eastern mediterranean from formation to reactivation 1 the levant continental margin eastern mediterranean is usually defined as a passive margin that developed between the late paleozoic early mid mesozoic previous studies suggest that the margin is composed of two segments with different structural characteristics the southern segment south of the carmel structure was formed by rifting whereas the origin of the northern segment is not known the present study focuses on the northern segment which is a key for understanding the tectonic history of the eastern mediterranean investigation is carried out offshore on two scales 1 deep crustal observations analysis of seismic refraction and magnetic data and their comparison with other continental margins worldwide and 2 shallow crustal scale observations of recent tectonic deformations based on multichannel and single channel seismic reflection profiles integration of the deep and shallow observations with reevaluation of geological data onland show strong structural resemblance between the northern levant segment and other transform margins a modified scenario is suggested for the formation and development of the levant basin and its margins combining all previous studies into one simple picture where a signature of older structures on more recent features is evident located in the midst of the progressive afro eurasian collision the northern levant presents a unique lifecycle for transform margins worldwide from formation to reactivation

the origin of sedimentary basins a status report from the task force of the international lithosphere program abstract better insights into the mechanisms of basin formation have a direct bearing on the predictive power of forward models for basin fill models that link flexure normal faulting and thrusting on a subbasin scale provide important constraints on the tectonic control of the sedimentary record enabling a quantitative comparsion with eustatic contributions to the basin architecture thus of special importance is the need to link processes with different spatial and temporal scales involved in the evolution of extensional and compressional basins by numerical modelling a new generation of basin modelling concepts and techniques is one of the main objectives of the task force origin of sedimentary basins of the international lithosphere program the focus of this work is on the quantification of the effects of the thermomechanical structure of the lithosphere and its interplay with regional and local stress changes other important developments include the step towards three dimensional modelling and the full integration of rapidly expanding fission track and other data sets to constrain vertical motions in basins as natural laboratories for the interactive testing and development of new basin modelling techniques a number of basins with high quality data from industry government and academia have been selected on the basis of specific testable problems

sedimentary basins and the blockage of lg wave propagation in the continents the phenomenon of lg blockage where lg is strongly attenuated by crustal heterogeneities poses a serious problem to ctbt monitoring because lg is an important seismic phase for discrimination this paper examines blockage in three continental regions where the lg blockages may be caused by large enclosed sedimentary basins along the propagation path the barents sea basin blocks lg propagation across the barents sea from the russian nuclear test sites at novaya zemlya to scandinavian stations also early lg waves are observed in sn codas on norsar noress and arcess recordings of novaya zemlya explosions where direct lg is blocked early lg waves may have resulted from sn to lg mode conversion at the contact between the barents basin and the kola peninsula the northern and southern caspian sea basins also block lg waves from pnes and earthquakes perhaps due to thick low velocity low q sediments replacing the granitic layer rocks in the crust lg blockage has also been observed in the western mediterranean levantine basin due to low q sediments and crustal thinning a basin capture model is proposed to explain lg blockage in sedimentary basins in this model shear waves that reverberate in the crust and constitute the lg wave train are captured delayed and attenuated by thick low velocity sediments that replace the granitic layer rocks of the upper crust along part of the propagation path sn waves which propagate below the basin would not be blocked and in fact the blocked lg waves may be diverted downward into sn waves by the low velocity sediments in the basin

segmentation of the levant continental margin eastern mediterranean 1 the levant continental margin is divided into two major segments by the carmel structure which extends from the dead sea fault into the eastern mediterranean new seismic reflection data over the unexplored northern segment are used for completing the structural framework of the levant area together with existing data south of it inclusive depth structural maps of the area were produced for the base pliocene and base messinian evaporites previous studies indicate that differences between the two segments are well expressed in the deep crustal structure the present study which focuses mainly on the shallow section shows that these differences are maintained throughout the accumulation of young sedimentary units and even in the bathymetry this preservation of segmentation both in the shallow and in the deep structure insinuates that the two segments were formed through different continental breakup processes which continue to dictate the style of sediment accumulation

tectonic isolation of the levant basin offshore galilee lebanon effects of the dead sea fault plate boundary on the levant continental margin eastern mediterranean abstract the continental margin of the central levant offshore northern israel and southern lebanon is characterized by a sharp continental oceanic crustal transition exhibited on the bathymetry as a steep continental slope at the base of the slope a narrow zone of faulting deforms the upper messinian recent sedimentary sequence further into the basin no major deformations are observed however onland a restraining bend along the dead sea fault plate boundary results in the formation of the lebanon and anti lebanon mountain ranges which exhibit a large positive isostatic anomaly not compensated at depth all these geologic features follow a nne ssw trend a dense network of multi channel and single channel seismic profiles covering 5000 km of ship track offshore northern israel and southern lebanon was analyzed for the purpose of characterizing the continental margin additional seismic surveys covering the area between the levant margin and the cyprean arc were examined data were then incorporated with magnetic gravity and earthquake measurements to reveal the deep crustal structure of the area and integrated with bathymetry data to describe the behavior of the young sedimentary basin fill results indicate that the levant basin offshore northern israel and southern lebanon up to beirut is more or less unaffected by the intense tectonic deformation occurring onland the transition between the deformed area onland and the undeformed levant basin occurs along the base of the continental slope along the base the upper messinian recent sedimentary sequence is cut by two sets of faults shallow growth faults resulting from salt tectonics and high angle faults marking the surface expression of a deeper crustal discontinuity the marine extension of the carmel fault zone the central levant continental margin is being reactivated by transpressional faulting of the marine continuation of the carmel fault at the base of the continental slope this fault system coincides with the sharp continental oceanic crustal transition and acts as an isolator between the levant basin and its land counterpart to the north this feature may initiate the formation of a new triple junction with the latakia ridge part of the eastern cyprean arc and the east anatolian fault

moho depth and three dimensional p and s structure of the crust and uppermost mantle in the eastern mediterranean and middle east derived from tomographic inversion of local isc data summary 82 000 p and s arrival times from 3000 sources recorded by 250 seismic stations from the revised isc catalogue are employed to study a circular area of 6 radius centred on the dead sea we use the linearized tomographic approach based on the rays constructed in a 1 d spherical velocity model and corrected for the moho depth variation and relief all the sources were relocated as the result of simultaneous iterative inversion we get 3 d p and s velocity anomalies in the crust and uppermost mantle moho depth and corrected source parameters the resulting images fit well with the existing tectonic elements in the study area in the crust a narrow p and s low velocity anomaly marks the position of the dead sea transform dst that is interpreted as sediments in the shallower layer and a zone of fractured and deformed rocks in the middle and lower crust there is a narrow 50 km wide band of thickening of the crust along the dst in the arava valley between the red sea and dead sea and some 100 km north of the dead sea this zone may be associated with the minimum of the lithospheric strength and therefore explain the location of the dst in the arava valley the velocity anomalies under the crust and the map of the moho depth clearly distinguish the oceanic levant basin and continental types of crust asia minor zagros cyprus and eratosthenes mount verification of the results takes an important part in this study inversions of different starting models and independent processing of data subsets show high robustness of the results synthetic tests clearly show the limits of the resolving power of the inversion with the existing data set

determination of the lower edges of magnetized bodies by using geothermal data summary the determination of the lower edges of magnetized bodies in the earth s crust is a complex geophysical problem although these values can be estimated by using geothermal data an analysis of the temperature regime and location of the lower edges of magnetized bodies has been carried out for the geosynclinal region of the southern caucasus and the area joining the ancient platform with the arabian shield in israel geothermal calculations for israel have been performed for three models of the thermal regime for the earth s crust and upper mantle the process of ultrabasic rock serpentinization is accompanied by the transformation of iron suboxide to iron oxide both these processes run under identical thermodynamic conditions within an average temperature interval of 200 400 c the curie surface controls the position of lower edges only in fault zones where oxidation conditions hold up to great depths

magnetic anomalies over the central levant continental margin abstract the magnetic field over the central levant continental margin off northern israel and southern lebanon and the adjacent levant basin has two distinct trends mount carmel and its offshore continuation carmel nose which are the surface expression of a large subbottom structure that extends from the land area across the continental shelf to the continental slope form a dividing zone between the two magnetic trends south of the carmel structure the magnetic field trends east west while north of the carmel structure it trends northeast and north northeast several pronounced magnetic anomalies exist mainly north of the carmel structure the majority of which trend north northeast and northeast parallel and sub parallel to the trend of the magnetic field in this area some also trend northwest perpendicular to the trend of the magnetic field in several cases the magnetic anomalies indicate large lithological elements which continue from land to sea gravity and seismic refraction data show that the two magnetic domains north and south of the carmel structure are associated with areas of different crustal structure south of the carmel structure the continetal oceanic crustal transition zone is located beyond the continental margin at the base of the continental slope while north of the carmel structure it is located under the continental shelf near the shore on land there are also differences in the structure of the crust north and south of the carmel structure the crust being much thinner north of the structure than south of it we suggest that some of the large magnetic anomalies off the central levant were formed during the rifting phase of the eastern mediterranean

accretionary processes at subduction zones in the eastern mediterranean abstract the tectonic history of the eastern mediterranean as well as the present tectonic style are affected by the collision and accretion of oceanic plateaus at subduction zones small but distinct oceanic plateaus exist today in the eastern mediterranean away from the plate boundary many other oceanic plateaus crowd the plate boundary particularly in the hellenic arc area their presence results in the unusual complexity of this subduction zone as is evidenced by the seismicity and bathymetry patterns the present two arcs system in this region the hellenic and cyprean arcs is probably the consequence of the collision of a large continental plateau with an older arc this plateau has been thrusted over the continental mass of anatolia and pieces of it are to be found in the region between the two arcs active subduction in the hellenic arc takes place in the outer trenches particularly in the ionian and strabo trenches subduction of mediterranean lithosphere in the pliny and ptolemy trenches is limited to their western parts inner segments of these trenches served as the main subduction trenches before the subduction zones migrated outward following the collision of oceanic plateaus

a review of the tectonics of the northern middle east region the structure of the northern part of the arabian platform is reviewed in the light of hitherto unpublished exploration data and the presently accepted kinematic model of plate motion in the region the palmyra and sinjar zones share a common history of development involving two stages of rifting one in the triassic jurassic and the other during late cretaceous to early tertiary times deformation of the palmyra zone during the mio pliocene is attributed to north south compression on the eastern block of the dead sea transcurrent system which occurred after continental collision in the north in southeast turkey the asymmetry of the palmyra zone is believed to result from northward underthrusting along the southern boundary facilitated by the presence of shallow triassic evaporites an important nw se cross plate shear zone has been identified which can be traced for 600 km and which controls the course of the river euphrates over long distances in syria and iraq transcurrent motion along this zone resulted in the formation of narrow grabens during the late cretaceous which were compressed during the mio pliocene to a large extent present day structures in the region result from compressional reactivation of old lineaments within the arabian plate by the transcurrent motion of the dead sea fault zone and subsequent continental collision

eastern mediterranean combined geological geophysical zonation and paleogeodynamics of the mesozoic and cenozoic structural sedimentation stages abstract the eastern mediterranean in the neo tethyan collision zone consists mainly of the mesozoic terrane belt and the adjoining oceanic crust complex of the northern part of the sinai plate the recent discovery of large hydrocarbon deposits has attracted considerable attention to this region combined analysis of gravity magnetic paleomagnetic tectonic structural and paleogeographical data sheds light on the tectonic evolution of this region the kiama paleomagnetic zone of inverse polarity discovered in the oceanic crust of the eastern mediterranean suggests transport along transform faults from the eastern part of the tethys ocean the discrepancy between the terrane belt and the nubian arabian foreland oceanic crust and terrane belt testify to the allochthonous nature of the eastern mediterranean for the first time formation paleogeographical maps of structural stages from the triassic to the neogene quaternary have been compiled the integrated tectono geophysical and paleogeographical specifics of deep zonation call for a reevaluation of regional criteria for oil and gas exploration

overview of the late tertiary recent tectonic and palaeo environmental development of the mediterranean region the late tertiary history of the mediterranean region exemplifies processes of ocean basin closure and continental collision as determined from integrated land and marine evidence during the mesozoic early tertiary tectonic settings were dominated by evolution of neotethys this ocean generally widened eastwards with a number of oceanic strands in the eastern mediterranean area great diversity of tectonic settings and palaeo environments developed during the tertiary closure history of these oceanic basins in the eastern mediterranean region more northerly neotethyan strands were closed by the mid tertiary while oceanic crust remained in the south in the present eastern mediterranean sea area northwards subduction of the remaining southerly neotethyan strand was probably active by the early miocene different areas exhibit different stages of convergence and ocean basin closure in the east the amalgamated eurasian plate had collided with the arabian margin africa by the late miocene while oceanic crust still persisted further west steady state subduction during the late tertiary gave rise to the mediterranean ridge as a substantial mud dominated accretionary wedge in the aegean area sufficient northward subduction took place to activate arc volcanism and pervasive back arc extension short of marginal basin opening in the easternmost mediterranean only limited subduction took place associated with supra subduction zone extension e g in cyprus today steady state subduction continues only locally where vestiges of neotethys remain e g herodotus abyssal plain in the western mediterranean area suturing of the african and eurasian plates initially took place in the betic region early mid tertiary where the neotethys had existed only as a narrow connection with the central north atlantic in the central mediterranean region where the western neotethys was wider northward subduction was active apparently as early as the late cretaceous in a widely accepted interpretation an andean type magmatic arc developed along the southern margin of europe and was then rifted off in the late oligocene early miocene to form the corsica sardinia block opening the north balearic marginal basin in its wake the migrating subduction zone and microcontinent then collided diachronously with north africa related continental units north africa and apulia from late oligocene early miocene giving rise to collisional thrust belts in the northern and southern apennines and along the north african continental margin i e the maghrebian chain to the betic rif area from the early miocene onwards a separate subduction system became active related to removal of neotethyan oceanic crust to the southeast ionian sea fueling suprasubduction zone extension and opening of the tyrrhenian sea orogenic collapse is an alternative mechanism of such extension and is widely believed to have caused divergent thrusting in the betic and rif regions of the westernmost mediterranean at the same time as crustal extension and subsidence of the alboran sea

seismic activity along fault branches of the dead sea jordan transform system the carmel tirtza fault system abstract about 550 earthquakes 1 0 m l 5 3 along the carmel tirtza fault a branching fault of the jordandashdead sea transform system recorded by the israel seismograph network isn between 1984 and 1994 were analyzed the seismicity pattern reveals significant activity often confined to known surface traces of active faults or within local grabens earthquake clusters are also observed the seismicity pattern within the mediterranean seems more diffuse possibly due to observational inaccuracies and insufficient knowledge of how the carmel tirtza fault system extends towards the northwest the seismicity along the carmel tirtza fault system since the beginning of this century is characterized by a b value of about 0 9 for 15 events with 3 1 m l 5 3 we found seismic moment estimates m 0 of 0 7 10 14 m 0 10 17 nm and brune stress drop estimates between 0 9 and 16 4 mpa these characteristics are comparable to those for events occurring on the main dead sea jordan transform fault ten individual earthquake focal mechanisms and three joint focal mechanisms for earthquake clusters have been obtained towards the northeastern part of the carmel tirtza fault system a left lateral motion seems to dominate while the seismicity pattern and the focal mechanism solutions near the branching of the carmel tirtza fault and the dead sea jordan rift suggest the present day existence of a complicated tectonic regime stress inversion assuming one stress tensor for the whole region indicates nne ssw extension and wnw ese compression

late tertiary seismic facies and structures of the levant passive margin off central israel eastern mediterranean abstract the late tertiary seismic facies and structures of the levant passive margin off central israel in the eastern mediterranean sea were studied by the interpretation of more than 3000 km of seismic reflection profiles most of them previously unpublished single channel profiles the neogene growth and evolution of this margin was influenced by the interaction of three main processes 1 the outbuilding and loading of the margin by the nile sediments since the pliocene 2 uplift and tectonic subsidence related to the tectonic activity along the dead sea transform and 3 the effect of the above processes on the thick messinian evaporites which caused many salt tectonic features including flowage piercement diapirs slumps and en echelon listric normal faults in the supra salt sediments we suggest that the study area may be divided into two segments north and south of caesarea these segments vary in their depositional environment the amount of sediment supply and load salt related features and tectonic activity we propose that the northern segment is affected by low sediment supply and by the continued uplift of the carmel structure and that this segment may even be a part of this structure the southern segment has been affected by the deposition and loading in the nile derived sediments since the pliocene three main depositional sequences were observed in the southern segment 1 sequence i early pliocene onlaps the top of the messinian evaporites representing a rise of sea level and renewed subsidence 2 sequence ii early pleistocene is lens shaped thinning to the north west and east and was derived during a relatively short time interval from the pre nile and 3 sequence iii since the pleistocene represents a major episode of continental shelf construction

crustal structure of northern israel abstract in the course of a seismic refraction wide angle reflection experiment in the eastern mediterranean an east west reversed refraction profile was recorded onshore northern israel the purpose of the line was to obtain reliable velocity and structural information about the crust in this area in addition a multi coverage reflection profile was shot over part of the refraction profile the results indicate that the crust in northern israel is a high velocity continental crust considerably thinner than the crust to the south the reflection profile indicates an unusually reflective upper crust and a transparent lower crust similar to those recorded at a number of compressional belts the overall results confirm the presence of a crust which is markedly different from that encountered to the south the provenance of which is probably very different

seismic refraction profiles between cyprus and israel and their interpretation summary a long seismic refraction profile was carried out between southern israel and cyprus the seismic energy was generated by 33 sea shots each of 0 8 t explosives and was recorded by land stations in israel and cyprus and by ocean bottom seismographs deployed along the profile the results showed that the continental crust of southern israel thins towards the mediterranean underneath a northward thickening sedimentary cover cyprus is underlain by a 35 km thick continental crust thinning south wards and extending to mt eratosthenes between mt eratosthenes and the israel continental shelf the crystalline crust is composed of high velocity 6 5 km s 1 material and is about 8 km thick it is covered by 12 14 km of sediments and may represent a fossil oceanic crust

oceanic plateaus the fragmentation of continents and mountain building many anomalous rises in today s oceans may be submerged continental fragments detached from previous continents ancient island arcs or basaltic piles formed by hot spots and spreading centers these rises are embedded in their respective moving oceanic plates and are fated to be consumed at active margins where such rises are being consumed at present e g the nazca ridge they cause cessation of volcanism disruption of the downgoing slab and possible shifts in plate boundary configuration many past rises including numerous continental fragments have been recognized within mountain belts as allochthonous terranes they constitute a large portion of the orogenic belts in the north pacific from mexico through western north america alaska east siberia japan and in new zealand the orogenic deformation in these belts is possibly the result of the accretion of the allochthonous terranes many terranes have been accreted with substantial deformation also in the alpine chain well before major continent continent collisions it is suggested therefore that the accretion of fragments may be the common process of the deformation phase of mountain building subduction of normal oceanic crust may be insufficient for deformation whereas full continent continent collision may not be necessary the general validity of this conclusion depends critically on whether allochthonous terranes caused orogenic deformation in the andes or not most of the accreted fragments with continental affinities in the mesozoic cenozoic orogenic belts of the world can be traced back to the breakup of gondwana beginning with a pacifica domain in the permian through a larger india domain in the early mesozoic and continuing through the separation of the somalia plate in the near future the reasons for this 250 million year breakup process are not known but some kind of thermal process possible of mantle wide scale is implied

crustal structure of the levant basin eastern mediterranean abstract a seismic refraction wide angle reflection experiment was undertaken in the levant basin eastern mediterranean two roughly east west profiles extend from the continental shelf of israel toward the levant basin the northern profile crosses the eratosthenes seamount and the southern profile crosses several distinct magnetic anomalies the marine operation used 16 ocean bottom seismometers deployed along the profiles with an air gun array and explosive charges as energy sources the results of this study strongly suggest the existence of oceanic crust under portions of the levant basin and continental crust under the eratosthenes seamount the seismic refraction data also indicate a large sedimentary sequence 10 14 km thick in the levant basin and below the levant continental margin assuming the crust is of cretaceous age this gives a fairly high sedimentation rate the sequence can be divided into several units a prominent unit is the 4 2 km s layer which is probably composed of the messinian evaporites overlying the evaporitic layer are layers composed of plio pleistocene sediments whose velocity is 2 0 km s the refraction profiles and gravity and magnetic models indicate that a transition from a two layer continental to a single layer oceanic crust takes place along the levant margin the transition in the structure along the southern profile is located beyond the continental margin and it is quite gradual the northern profile north of the carmel structure presents a different structure the continental crust is much thinner there and the transition in the crustal structure is more rapid the crustal thinning begins under western galilee and terminates at the continental slope the results of the present study indicate that the levant basin is composed of distinct crustal units and that the levant continental margin is divided into at least two provinces of different crustal structure

crustal and upper mantle structure across the dead sea rift and israel from teleseismic p wave tomography and gravity data abstract new findings of the structure of the crust and the upper mantle across the dead sea rift and israel were obtained by applying p and pkp wave relative travel time residuals inversion of 612 teleseisms recorded by the seismic networks in israel and jordan independently of the relative teleseismic travel time residuals the bouguer gravity anomalies were used as an additional aid to examine the structure of the crust and upper mantle an examination of the teleseismic travel time residuals in israel suggests the existence of two prominent provinces of distinct crustal structure the northward increase of the teleseismic travel time residuals is in good agreement with a gradual thickening of the sedimentary sequence and a simultaneous thinning of the crust examination of the inverted velocity anomalies indicates that the upper and lower crusts are sub divided into a number of structures we identify several velocity anomalies that are associated with prominent geological structures the southern dead sea basin is characterized with the largest decrease of velocity in both upper and lower crustal layers due to the infilling of light material relative to the surrounding material the velocity anomaly in the carmel structure is probably associated with variations in the upper part of the upper mantle examination of a cross section that traverses the dead sea transform supports the existence of lighter mass density material on the eastern side relative to that on the western side

lithospheric folding in iberia integration of stress indicator data gravity data crustal kinematics data and analysis of topography and recent vertical motions demonstrates the occurrence of consistently oriented spatial patterns of large scale alpine to recent intraplate deformation in iberia the inferred upper crustal and lithospheric deformation patterns and the timing of the associated expressions at or near the surface support the existence of a close coupling with plate boundary processes operating at the margins of iberia patterns of lithosphere and upper crustal folds are oriented perpendicular to the main axis of present day intraplate compression in iberia inferred from structural analysis of stress indicator data and focal mechanism solutions these findings suggest the presence of lithospheric folds with wavelengths compatible with theoretical predictions of folding wavelengths of variscan lithosphere stress induced intraplate deformation set up by plate interactions is compatible with indications for the absence of present day deep mantle lithosphere interactions inferred from seismic tomography

continental margin evolution of the northern arabian platform in syria copyright aapg 1993 reprinted by permission of the aapg whose permission is required for further use see also http atlas geo cornell edu syria best 1993 html

late tertiary subsidence history of the southern levant margin eastern mediterranean sea and its implications to the understanding of the messinian event the late tertiary subsidence history of the southern levant continental margin situated in the southeastern mediterranean sea was quantitatively analyzed paleodepth reconstruction across the margin off ashdod suggests the existence of a deep basin in pre messinian time which resembles the present one this implies that the deposition of the evaporites in the study area during the messinian desiccation of the mediterranean sea occurred in a deep basin the path of the tectonic subsidence of the basement since early tertiary is generally smooth as expected from the nature of the thermal subsidence the unconformity beneath the messinian indicates erosion of 50 200 m at the coastal plain in the pliocene the tectonic subsidence in the coastal plain and shelf area diverts from the expected thermal path and increases from 250 m to 450 m respectively in the quaternary the rate of tectonic subsidence nearly resumed the predicted thermal subsidence sedimentation and subsidence rates decrease but are still higher than those of the pre messinian we suggest that the evolution of the southern levant margin is most probably influenced by three main causes 1 the messinian event in late miocene 2 the deposition of large volumes of nile derived sediments since the pliocene and 3 the flexural response of the lithosphere to the load from the nile delta and or from the uplift of the judea mountains the western shoulder of the dead sea transform we interpret the latter to be the cause of the anomalous subsidence of the southern levant margin during the pliocene

crustal structure of the dead sea basin from local earthquake tomography summary new findings of the velocity structure of the crust across the dead sea basin are obtained by applying tomography based method to local earthquakes we use p wave traveltime of 614 earthquakes that occurred in the dead sea basin in 1983 2009 at all depths the dead sea basin is characterized by lower velocities relative to both the eastern and western sides of the basin there is significant seismic activity at a depth of about 20 km mainly in the centre and the northern part of the basin at shallow depths 15 km there is more seismic activity on the eastern side of the basin than on the western side and the northern basin is generally more active than the southern basin asymmetry is also observed in the faults that border the dead sea basin the arava fault on the eastern side with nearly vertical dip faulting appears to be a clear boundary at all depths down to about 20 km the depth extension of the jericho fault on the western side of the basin is definitely limited to less than 15 km at greater depths of 20 km or more the western side is only partially bounded by a fault the concentration of earthquakes in the central part of the basin at depths larger than 15 km suggests that the dead sea fault at those depths acts as one single fault that is located in or near the central axis of the basin the existence of a number of clusters of earthquakes that spread from shallow depths of a few kilometres up to a depth of about 22 km points to several defined faults that traverse the dead sea basin one such example is the aftershock sequence of the 2004 earthquake that occurred in the northern dead sea basin seismic activity near mt sodom is relatively low and occurs at shallow depths down to 10 km whereas at larger depths 15 km it ceases this implies that the whole structure is relatively shallow with no wide and deeper extension seismic activity near and within the lisan peninsula extends to somewhat larger depths 15 km and then it ceases the occurrence of earthquakes at large depths suggests that the upper and the lower crust are relatively cool as was also suggested by earlier studies pointing to the fact that the heat flow is significantly below the global average value

age and structure of the levant basin eastern mediterranean abstract large parts of the mediterranean were formed during the mesotethys ocean opening and subsequently became land locked in the midst of the africa eurasia plate convergence since the neogene this convergence has concealed key sections of the original basins previous studies widely agree that the easternmost part of the mediterranean the levant basin opened during the permian to early jurassic pj and accordingly explain the architecture of the basin and its margins however since the pj model was suggested in the late 1990 s a flood of new evidence has arrived since the hydrocarbon exploration some of which do not fit in with the pj model and some remain unexplained the current research re examines the old and new evidence from the levant basin its margins the surrounding landmass the adjacent eratosthenes seamount and the eastern part of the herodotus basin the integration of geological and geophysical data suggests that the levant basin formed 100 myr later than previously thought i e during the cretaceous its opening was triggered by the levant nubia mantle plume that induced a sequence of wide spread ocean island basalt volcanism the resulting crustal updoming and stretching led to the breakup of the levant landmass since 141 ma and drifting of the eratosthenes seamount since 125 ma back arc extension shaped the levant basin as a hybrid crust comprising continental slivers intervened by oceanic patches the basin opened during the long normal cretaceous polarity chrons between 122 and 84 ma and therefore it does not show any magnetic lineation the opening of the levant basin occurred while the herodotus basin floor subducted eastward under the eratosthenes seamount the subduction hinge did a roll back and facilitated the seamount drifting the seamount absorbed intensive volcanism while chasing the subduction roll back and sliding between two subduction transform edge propagator step faults that bounded the stretching levant back arc basin the turonian maastrichtian compression stress regime or inversion halted the extension of the levant basin stagnated its hybrid fabric and prevented the development of a spreading center the evolutionary scenario suggested here is a game changer for future exploration in the levant and may serve as a global analog for the formation of marginal seas

cenozoic volcanism in the middle east petrogenesis of alkali basalts from northern lebanon large discontinuous exposures of basaltic lava flows ranging in age mostly from miocene to recent are present in several localities extending from sinai jordan palestine israel to lebanon and syria dubertret 1955 baldridge et al 1991 mouty et al 1992 heimann et al 1996 shaw et al 2003 these form the cenozoic volcanic province of the middle east occurring mostly along or near the transform faulted boundary the dead sea ghab transform fault system between the arabian and african plates and the levantine subplate fig 1 further to the south several other extensive cenozoic volcanic provinces occur in arabia and east africa mostly ethiopia figure 1 regional geological map showing the distribution of the various cenozoic volcanic provinces in east africa arabia and the middle east the cenozoic continental flood basalts in ethiopia yemen western arabia and jordan have been extensively studied camp roobol 1989 1992 altherr henjes kunst baumann 1990 stein hofmann 1992 baker thirlwall menzies 1996 baker et al 1997 shaw et al 2003 the cenozoic volcanic province of ethiopia is clearly related to the east african rift system barberi et al 1975 mohr 1983 the quaternary intraplate basaltic volcanic field in yemen appears to be the result of melting shallow mantle perhaps in response to small amounts of lithospheric extension that were metasomatized and hydrated by the afar plume during or shortly after oligocene flood volcanism baker et al 1997 the lavas of this basaltic field of western yemen were subjected to variable degrees of contamination 0 20 of an early proterozoic to late archaean silicic lower crustal component baker thirlwall menzies 1996 baker et al 1997 the cenozoic continental flood basalt provinces of

a crustal structure study of jordan derived from seismic refraction data abstract the interpretation of a deep seismic refraction study in jordan performed in may 1984 shows that much of the country is underlain by continental crust 32 35 km thick and normal mantle with a velocity of 8 0 8 2 km s in the aqaba region southwest and central jordan east of wadi araba the crustal thickness is of the order of 32 35 km while in the amman region it is not less than 35 km in southeast jordan the crust thickens to at least 37 km in what is probably the transition to the arabian shield type of crust the boundaries between the upper and lower crust at about 20 km depth and the lower crust and uppermost mantle are probably transition zones the upper crystalline crust has velocities of 5 8 6 5 km s while the lower crust has velocities greater than or around 6 65 km s while the crystalline basement is exposed in southwest jordan and is at a depth of 2 2 5 km north of amman it is at a depth of not less than 5 km in central jordan a comparison of the crustal type and structure of jordan and the adjacent dead sea rift with that of the black forest and the rhine valley yields a striking resemblance the situation of the jordan dead sea rift is explained in terms of the continental crust of arabia rifting in preference to the thin oceanic crust of the mediterranean sea

faulting processes along the northern dead sea transform and the levant margin the northern dead sea transform is markedly different from the southern segments of the transform the strike of the transform changes in this area that forms a restraining bend and the displacement on it is much less than that on the southern and central dead sea transform the structure and evolution of the northern dead sea transform was simulated using a rheological model of a visco elastic material that takes into consideration the crustal structure variations in this area and the proximity to the collisional belts along the cyprean arc and the taurus mountains the simulation can explain the formation of the restraining bend known in this area as the yammuneh fault and the faulting along the northern levant continental margin providing that a simultaneous propagation of the dead sea transform from the north and south took place this suggests that restraining bends in general which are common features along continental transform faults are formed when two segments of a transform propagate toward each other

displaced terranes and crustal evolution of the levant and the eastern mediterranean geophysical data from the levant and the eastern mediterranean suggest that this area can be divided into distinct crustal units of different origins for example a marked difference in crustal structure and structural style exists in the levant between samaria and judea south of the carmel structure and the galilee and lebanon north of it on the other hand several microcontinental fragments such as cyprus and the eratosthenes and anaximander seamounts are embedded within the oceanic crust of the eastern mediterranean the present location of these units has resulted from complex tectonic processes which were active during the mid paleozoic mesozoic evolution of this area during this period several crustal units were accreted to the northern margin of africa while others were detached away from it the crustal evolution of the eastern mediterranean and the levant is intimately linked with the closure of the paleo tethys the formation of the neo tethys and its subsequent closure

the deep structure of the carmel fault zone northern israel from gravity field analysis the carmel yizre el jordan fault system is a major structural feature in the geology of israel there is a great difference in topographical features structural style seismic activity crustal structure and other geological characteristics to the north and south of this fault system we examine the gravity field of the region around the fault system by combining the techniques of upward continuation and horizontal gradient analysis the results suggest the existence of a system of deep seated n s trending faults that are probably related to the continental breakup of the region in the triassic jurassic the present complex deformation of the area is the result of interaction between the older faults system and the younger stresses resulting from the formation of the dead sea rift

imaging a relic of complex tectonics the lithosphere asthenosphere structure in the eastern mediterranean the crust and upper mantle structure of the eastern mediterranean is investigated through the nonlinear inversion of raleigh wave dispersion curves extracted from broadband records in the region along two profiles crossing the hellenic and cyprian arcs corresponding density models are constructed consistent with the observed gravity anomalies the modelled profiles exhibit a continental crust type overlain by a thick sedimentary cover and underlain by a thick lithospheric mantle the lithosphere asthenosphere system exhibits features which suggest the presence of upducted asthenosphere exhumed to the north of the hellenic arc where the slab extension is limited to depths of about 220 km

nature of the levantine eastern mediterranean crust from multiple source werner deconvolution of bouguer gravity anomalies the nature of the levantine eastern mediterranean crust has been the subject of controversy for many years revolving around two hypotheses the continental crust hypothesis and the oceanic crust hypothesis the proponents of the first hypothesis suggest that the levantine eastern mediterranean basin is characterized by a thick sedimentary succession overlying thinned crust of continental origin through which a number of aborted mesozoic rifts were etched however multiple source werner deconvolution mswd estimates and other geophysical data integrated with earlier geological and geophysical results provide further support to the second hypothesis oceanic crust and lead to the following conclusions 1 the depth to moho ranges from about 20 km to about 28 km below sea level with an average crustal thickness of about 22 km 2 the large thickness about 10 km of phanerozoic section leaves only about 12 km of thickness for the igneous metamorphic basement complex 3 the northern boundary of the levantine easternmost mediterranean lithosphere is delineated by an arcuate belt of seismic activities along the southern margin of cyprus 4 the formation of the phoenician and latakia basins and the iskenderun bay is probably controlled by the counterclockwise rotation of the lithospheric slices southeast of cyprus 5 the apparent absence of magnetic anomaly lineations reversals is due probably to the thick phanerozoic cover and or the formation of the oceanic crust during a long magnetic chron

anomalous enrichments of iron monosulfide in euxinic marine sediments and the role of h 2 s in iron sulfide transformations examples from effingham inlet orca basin and the black sea it is well documented that sedimentary pyrite formation proceeds through an iron monosulfide fes precursor laboratory studies have tradition ally indicated that intermediate s species such as elemental sulfur s 0 or polysul fides sx 2 are responsible for the transformation of fes to pyrite fes2 recent experimental work however has suggested that h2s may also be responsible for the transformation the present study extrapolates reaction pathways respon sible for pyrite formation in the laboratory to two fundamentally different modern anoxic marine systems we hypothesize that on decadal timescales h2s or hs is responsible for transformations of fes into fes2 in natural systems where intermediate s species are isolated from fes production the possibility of prolonged coexistence of high levels of h2s and fes however challenges recent experimental predictions of extremely rapid transformations that is timescales of hours or less of fes to fes2 via the h2s pathway sediments of effingham inlet a fjord on vancouver island and the orca basin an intraslope brine pool in the northern gulf of mexico are both charac terized by atypically high concentrations of fes but contrasting levels of h2s and fes2 production in both systems fes formation is spatially decoupled from intermediate s species as a consequence of either rapid deposition burial or extreme water column stratification within settings that promote this separa tion h2s may be the principal species responsible for pyrite formation fes to fes2 transformations are favored by the high concentrations of h2s in sediments of effingham inlet additional results from the margin of the anoxic black sea corroborate the effingham model for iron sulfide transformation h2s concentrations are controlled by the amount of bacterial sulfate reduc tion and the availability of reactive fe h2s concentrations will be buffered to low levels via the production of fes in systems with appreciable amounts of reactive fe and therefore be unavailable to transform fes to fes2 under conditions where h2s is the only species available for fes to fes2 transformations some degree of fe limitation may promote pyrite formation by allowing h2 st o accumulate in the pore waters ultimately this balance between h2s production and reactive fe availability may strongly influence the amount of pyrite formed in anoxic systems