late cretaceous to palaeogene thin skinned tectonics of the palmyrides belt syria abstract detailed mapping in the palmyrides belt syria shows that its structure resulted from thin skinned tectonics and includes duplexes anticlinal stacks and imbricate thrusts in the frontal palmyrides the main decollement level is formed by triassic evaporites but a cenomanian marl interval locally forms a subsidiary decollement ramps linking the two decollement levels generate duplexes formed by thin horses of jurassic and lower cretaceous material to the north in the central palmyrides the decollement ramps down from a triassic to an eocambrian level in which it continues as a main basal decollement the ramp connection between the cambrian and triassic decollement levels is responsible for the anticlinal structure of the central palmyrides bilas block accurate mapping balanced cross sections and forward deformation modelling allowed calculation of the amount of shortening of the sedimentary cover the minimum estimate is 20 km this independent field based result is compatible with previous estimates from a general seismic study of the cenozoic mesozoic series due to the presence of folded neogene deposits the deformation of the palmyrides belt was thought to be miocene pliocene in age however eocene carbonates unconformably overlie various thrust units in the frontal palmyrides reconstruction indicates 15 km of shortening during the late maastrichtian to upper eocene and 5 km of shortening since the late miocene thus the main shortening event of the palmyrides occurred during the palaeocene seismic well and gravity data are used to integrate the shallow structure in a crustal scale deformation model gravity modelling confirms previous interpretations of a relatively flat moho beneath the palmyrides belt and suggests that deformation of the belt resulted from a movement of the sedimentary cover of northern syria 20 km to the south along a 200 km long flat decollement within the eocambrian this syrian decollement between the sedimentary cover and the basement is supposed to root down north of syria within the north arabian plate boundary such a decollement implies four times more shortening in the sedimentary cover than in the palmyrides basement

crustal shortening in the palmyride fold belt syria and implications for movement along the dead sea fault system an edited version of this paper was published in tectonics by the american geophysical union agu copyright 1990 agu see also http www agu org journals tc http atlas geo cornell edu syria chaimov tectonics 1990 html

volcanic morphology of west mata volcano ne lau basin based on high resolution bathymetry and depth changes high resolution 1 5 m mapping from the autonomous underwater vehicle auv d allan b of west mata volcano in the northern lau basin is used to identify the processes that construct and modify the volcano the surface consists largely of volcaniclastic debris that forms smooth slopes to the nw and se with smaller lava flows forming gently sloping plateaus concentrated along the ene and wsw rift zones and more elongate flows radiating from the summit two active volcanic vents prometheus and hades are located 50 and 150 m wsw of the 1159 m summit respectively and are slightly nw of the ridgeline so the most abundant clastic deposits are emplaced on the nw flank this eruptive activity and the location of vents appears to have been persistent for more than a decade based on comparison of ship based bathymetric surveys in 1996 and 2008 2010 which show positive depth changes up to 96 m on the summit and north flank of the volcano the widespread distribution of clastic deposits downslope from the rift zones as well as from the current vents suggests that pyroclastic activity occurs at least as deep as 2200 m the similar morphology of additional nearby volcanoes suggests that they too have abundant pyroclastic deposits

mesozoic and cenozoic deformation inferred from seismic stratigraphy in the southwestern intracontinental palmyride fold thrust belt syria this paper was published in the geological society of america bulletin the geological society of america retains the copyright to this paper geological society of america p o box 9140 boulder co 80301 9140 usa see also http www geosociety org http atlas geo cornell edu syria chaimov gsa bull 1992 html

basement depth and sedimentary velocity structure in the northern arabian platform eastern syria an edited version of this paper was published in geophysical journal international by blackwell publishing blackwell publishing retains the copyright see also http www blackwellpublishing com journal asp ref 0956 540xs http atlas geo cornell edu syria brew gji 1997 htm

seismic depth domain stratigraphic classification of the golan heights central dead sea fault abstract a set of twenty five 2 d seismic profiles acquired over the golan heights basaltic plateau central dead sea fault segment was processed and analyzed in the depth domain the data were processed by the pre stack depth migration techniques and despite the thick basaltic layer entirely covering the plateau shows surprisingly good quality the study presents stratigraphic identification of eleven seismic markers recognized on the output depth domain sections and their correlation with the adjacent syrian jordanian and israeli stratigraphic columns based on this regional correlation the deep seated structure and stratigraphic column underlying the extensive basaltic cover are addressed through structural mapping and isopach calculations as well as through compilation of regional geological cross sections results of the depth domain seismic interpretation suggest that the golan heights covers a structural depression in which more than 8500 m of late proterozoic to neogene sedimentary succession has accumulated amid the jordanian highlands and the mt hermon anticline the infracambrian paleozoic succession attains a thickness of 3000 3500 m while as much as 1500 m of this figure is attributed to the late proterozoic saramuj formation the mesozoic succession outlined by the significant northward and north western thickening of the triassic and jurassic successions attains a cumulative thickness of 5 km in the northern golan the senonian cenozoic succession outlines the syncline nature of the golan plateau attaining a thickness of 1 5 2 km at the central parts of the plateau the estimated thickness of the plio pleistocene basalt flows that cover the study area locally exceeds 1000 m two fault strands of the dead sea fault system are recognized in the subsurface of the plateau the sheikh ali and shamir faults the strands are interpreted beneath the basalt cover extending into the plateau at a considerable distance from their surface expression next to the arabian sinai plate boundary frontier exhibiting various styles of deformation

structure and tectonic development of the ghab basin and the dead sea fault system syria we examine the structure and evolution of the ghab basin that formed on the active yet poorly understood northern segment of the dead sea transform fault system the basin formed in plio quaternary time at a complex step over zone on the fault subsidence occurred along cross basin and transform parallel faults in two asymmetric depocentres the larger depocentre in the south of the basin is asymmetric towards the east the margin along which most active transform displacement apparently occurs the syrian coastal ranges located directly west of the ghab basin are a consequence of late cretaceous and cenozoic regional compression heavily modified by the dead sea fault system and ghab basin formation we prefer a model whereby the dead sea fault system in northwest syria developed in plio quaternary time consistent with previously proposed models of two phase dead sea fault system movement and red sea spreading

hydroacoustic detection of volcanic activity on the gorda ridge february march 1996 abstract beginning at 0700 gmt on 28 february 1996 intense seismicity was detected in the northeast pacific ocean using the t phase monitoring system developed by noaa pmel to access the u s navy s sound surveillance system sosus in the north pacific the event was preliminarily located on the northernmost segment of the gorda ridge near 42 67 n and 126 8 w in the vicinity of the ridge segment high narrowgate the nature of the seismicity was similar to that observed in june 1993 at the coaxial segment of the juan de fuca ridge which was later documented to be a lateral magma injection with subsequent eruption due to several gaps in the data the detection information was not as comprehensive as during the coaxial event but an initial migration of epicenters from the narrowgate area down rift is inferred based on arrival bearings from a single array there is evidence for an additional diking event on the second and third day of activity there is also indication of a concentration of epicenters located near 42 6 n as occurred during the coaxial episode at what was later determined to be an eruption site examination of t wave rise times generally supports this interpretation based on the nature and duration of the activity a response effort was initiated which later confirmed hot water plumes and fresh lava flows at the site based on both hydroacoustic information and field observations it is proposed that the episode began with a lateral dike injection possibly with eruptive activity in the summit region followed by multiple magma pulses and eventual focusing of the seismic activity and extrusion near 42 6 n

seismic reflection structure of intracratonic palmyride fold thrust belt and surrounding arabian platform syria copyright 1990 aapg reprinted by permission of the aapg whose permission is required for further use see also http aapgbull geoscienceworld org http atlas geo cornell edu syria mcbride aapg 1990 html

bouguer gravity trends and crustal structure of the palmyride mountain belt and surrounding northern arabian platform in syria copyright 1990 geological society of america see also http dx doi org 10 1130 2f0091 7613 281990 29018 3c1235 3abgtacs 3e2 3 co 3b2 http atlas geo cornell edu syria best 1990 html

crustal structure of central syria the intracontinental palmyride mountain belt an edited version of this paper was published in tectonophysics by elsevier science copyright 1992 elsevier science see also http dx doi org 10 1016 0040 1951 92 90395 m http atlas geo cornell edu syria al saad et al 1992 html

on the supposed precambrian palaeosuture along the dead sea rift jordan the evidence that the dead sea rift has existed as a zone of crustal weakness since precambrian time is critically examined based on i the distribution and abundance of dykes in the precambrian basement and ii the distribution of the lower cambrian basal conglomerates it is shown that dyke and clastic sediment occurrence is not preferentially associated with the modern rift zone and thus that some earlier tectonic interpretations must now be discounted

mesofabric microfabric and submicrofabric of ice thrust bedrock highvale mine wabamun lake area alberta the fabric of the ice thrust argillaceous bedrock from a shear zone was studied in hand specimens under a polarizing microscope and a scanning electron microscope the fabric included principal di

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

paleostress analyses in nw syria constraints on the cenozoic evolution of the northwestern margin of the arabian plate abstract fault analysis between the dead sea transform and the euphrates region in northern syria shows two main directions of compression connected to the recent evolution of the northwestern wedge of the arabian plate e w open folds due to n s compression gently deform the cretaceous to tortonian successions of the aleppo plateau and the eastern termination of the palmyrides west of the euphrates conjugate sets of strike slip and normal faults pre as well as post dating folding occur in the plateau and are still consistent with the same stress field n s normal faults cross recent deposits and control quaternary volcanoes along the euphrates suggesting the persistence of this stress regime a nw se compression related to the syrian segment of the dead sea transform dst was detected in the western part of the study area the activation of large n s left lateral strike slip and wnw ese right lateral faults follows in time the growth of in line folds and thrusts permutation of the 1 and 2 stress axes is related to activation of nw se normal faults which generally accompany strike slip faults and post date e w folds within the plateau recent e w extension in the euphrates region is consistent with a horizontal n s maximum direction of compression and seems to be partially coeval with the stress regime induced by the dst this stress pattern can be explained by the superposition of the northward push of the arabian plate to the n s left lateral shearing along the dst

anisotropy of a shear zone the behaviour of landslides in clay is essentially governed by a shear zone located at the base of the soil mass while some data regarding the shear zones of slides are available information is rather poor about the shear zones of mudslides the paper reports some results of investigations on the shear zone located at the base of a mudslide showing the strong hydraulic and mechanical anisotropy of the material

some outstanding issues in the geology of lebanon and their importance in the tectonic evolution of the levantine region abstract the concept of pervasive and disruptive late neogene quaternary strike slip tectonics in lebanon has made establishing a satisfactory pre neogene palaeogeographic and palaeotectonic history for the area difficult research has allowed clarification of three fundamental issues that permit the setting of lebanon against its adjacent regions to be more firmly assigned the first issue is the identification of the significance of the 100 km long nne ssw trending monocline of the western lebanon flexure this feature is interpreted as a modified and rejuvenated early mesozoic hinge line that is presumed to be the northern continuation of the carmel sinai hinge line to the south the second issue is the correlation of the mount lebanon bekaa and anti lebanon complex with the adjacent intracontinental palmyride fold belt of syria through recognition in each of common divisions in structural style between a higher northern zone dominated by broadly spaced box folds and a lower southern zone with more numerous closely spaced and more internally complex folds the third issue involves the identification of major two stage late cretaceous to palaeogene syrian arc tectonism within lebanon resolution of these issues suggests a tectonic model for the region whereby the levantine region formed in two main phases the first of these was the multiphase late palaeozoic early mesozoic rifting of the area which imposed a fundamental extensional fabric over much of the region the second tectonic phase was the subsequent inversion of these extensional structures in the two stage syrian arc deformation of senonian and late palaeogene age which gave rise to the main lebanon structures it is this syrian arc tectonism rather than the late cenozoic strike slip that was probably the main structuring agent which affected the lebanon area the transpression from the braided dead sea fault motion although locally complex is an essentially neotectonic overprint on an already existing fabric offset of syrian arc structures in lebanon suggests that the total sinistral motion of the yammouneh fault segment of the dead sea fault is around 47 km

long term investigations on the pore pressure regime in saturated and unsaturated sloping soils abstract pore pressure changes play a major role in the stability of natural slopes whose safety factor value is usually much smaller than that generally accepted in any other geotechnical problem correct assessment of potential seasonal pore pressure distributions is therefore a crucial issue in slope stability analysis based on long term monitoring of some natural slopes this paper compares the pore pressure distribution recorded in saturated fine grained deposits and in shallow unsaturated granular covers both monitored in southern italy in spite of the expected differences the soils display some common features in particular from december to mid may wet period in all examined cases the pore water pressures are quite constant over a monthly scale thus an essentially steady state pore pressure condition establishes it is in this phase which is characterised by an essentially downward flux that the safety factor drops to its lowest yearly value finally a simplified method is adopted to model the steady state pore pressure during the wet period and to calculate the average rain infiltration in equilibrium with the steady state condition the results thereby obtained are compared with the findings of an advanced approach based on the hydrological balance

joint inversion of local regional and teleseismic data for crustal thickness in the eurasia africa plate boundary region summary a new map for the moho discontinuity eam02 in the eurasia africa plate boundary region is presented reliable results have also been obtained for the southern and eastern mediterranean basin the northern african coasts and the eastern atlantic ocean regions only occasionally considered in studies on the mediterranean region the moho topography model is derived from two independent sets of constraints information contained in the fundamental and highermode rayleigh waves obtained from waveform modelling is used to constrain the moho depth between estimates of crustal thickness taken from published reflection and refraction surveys gravity studies and receiver function analysis strong lateral variations in the moho topography have been observed in the mediterranean sea confirming the complex evolution of this plate boundary region in the west the moho discontinuity has been found at 15 20 km depth suggesting extended and at least in some locations oceanic crust while in the east the crust is on average 25 30 km thick there it is interpreted either as mesozoic oceanic or thinned precambrian continental crust covered by thick sedimentary deposits standard continental crust 30 35 km is observed along the eastern part of the northern african coast while to the west a rapid change from a relatively deep moho down to 42 km below the atlas mountain range to the thin crust of the southwestern mediterranean sea has been found the crust beneath the eastern north atlantic ocean can be up to 5 km thicker compared with standard oceanic crust 6 km the crust has been interpreted to be heterogeneous as a consequence of irregular magma supply at the mid atlantic ridge in addition serpentinization of the submoho mantle could contribute to the imaging of apparently anomalous thick oceanic crust in europe the presence of crustal roots 45 km beneath the major mountain belts has been confirmed while thin crust 25 km has been found beneath extensional basins comparing the obtained moho topography and moho depth computed assuming isostatic compensation at 60 km depth shows that most of the mediterranean and eastern atlantic region appears to be in isostatic equilibrium the large positive residuals observed for the eastern mediterranean are likely to be due to overestimating crustal thickness owing to the thick sediment deposits present

tectonic and deposition model of late precambrian cambrian arabian and adjoining plates during the late precambrian the terranes of the arabian and adjoining plates were fused along the northeastern flank of the african plate in gondwanaland this phase which ended approximately 640 to 620 ma was followed by continental failure 620 to 580 ma and intracontinental extension 600 to approximately 550 ma during the infracambrian extensional phase a triple junction may have evolved near the sinai peninsula and may have consisted of the 1 jordan valley and dead sea rift branch 2 sinai and north egypt rift branch and 3 the najd wrench rift branch the najd hawasina and zagros fault systems may have been transverse faults that accompanied rifting in the arabian gulf and zagros mountains southern oman pakistan and kerman in central iran while the area was extending and subsiding the tethys ocean flooded the eastern side of the arabian plate and iran and deposited calcareous clastics carbonates and evaporites including the hormuz and ara halites this transgression extended into the western part of the arabian plate via the najd rift system the termination of the extensional phase during the late early cambrian was accompanied by a major regression and terrestrial conditions on the arabian peninsula however by the early ordovician as sea level peaked to a highstand the arabian plate was blanketed with marginal marine sediments

constraints on arabian plate motion and extensional history of the red sea analysis of the geologic and geophysical data from the western and northern margin of the arabian plate combined with data from the red sea gulf of aden leads to an interpretation of arabian plate motion that supports an episodic extensional history in the red sea and gulf of aden phase 1 extension began in medial to late eocene and was caused by the nw propagation of the reoriented central indian ridge spreading center it stretched and thinned continental crust along numerous wrench and normal faults that reactivated preexisting structures first phase extension stopped when the arabian plate terminally sutured to eurasia in the medial miocene and halted northward movement of arabia relative to africa the combined african arabian plates moved north more slowly constricting and thickening continental crust in the bitlis zagros sutures while the red sea remained technically quiescent and accumulated salt by the early pliocene continued northward movement was accommodated by lateral extrusion of large continental wedges north of the bitlis zagros sutures this allowed arabia to move northward faster than africa and reopen the red sea where phase 2 extension was expressed by seafloor spreading extension within the red sea gulf of aden rift system has been controlled by the interactions and effects of two factors 1 convergent processes between the north margin of the arabian plate and the eurasian plate to the north and 2 northwest propagation of extension associated with the medial eocene reorganization of the central indian spreading center

crustal structure of the northern levant region multiple source werner deconvolution estimates for bouguer gravity anomalies summary the opening of the gulf of aden and the red sea and the collision of the arabian plate with the jigsaw southern margin of the anatolian plate have sheared the sinai levant microplate off the nw part of the arabian plate and created the left lateral dead sea levant transform fault the structural setting of the northern levant region particularly lebanon and the palmyrides has been complicated by detachments along incompetent evaporitic horizons roughly separating the post triassic succession from the underlying crustal material the interpretation of the multiple source werner deconvolution mswd estimates of bouguer gravity profiles which were separately calculated for syria and lebanon integrated with the available geological and geophysical results leads to the following interpretations 1 the crust of syria thickens southeastwards from approximately 32 km under the al ghab graben to 36 km under the aleppo high the palmyride fold belt and the rutbah high 2 the lower crustal basaltic layer thickens northwestwards from the hinterland to the al ghab graben at the expense of the overlying andesitic layer 3 the mid beqa a fault is delineated by the mswd estimates in lebanon and its ne extension in syria 4 the phanerozoic section in the southwesternmost parts of the palmyrides is 13 km thick and the shortening there could exceed 30 km 5 the palmyride fold belt and the serghaya and mid beqa a faults could have accounted for about 70 km of the 105 km left lateral displacement along the southern segment of the dead sea transform fault system without transmission to the syrian northern segment of the fault system 6 the splitting of the dead sea transform fault in the kuleh depression into the serghaya mid beqa a yammouneh and roum faults could be explained by the rotation of the detached post triassic succession over a stable deep left lateral fracture of the dead sea fault in the underlying crustal material

a record of eruption and intrusion at a fast spreading ridge axis axial summit trough of the east pacific rise at 9 10 n 1 high resolution side scan sonar near bottom multibeam bathymetry and deep sea photo and bathymetry traverses are used to map the axial summit trough ast at the east pacific rise between 9 and 10 n we define three ridge axis morphologic types no ast narrow ast and wide ast which characterize distinct ridge crest domains spanning tens of kilometers along strike near bottom observations modeling of deformation above intruding dikes and comparisons to the geologic and geophysical structure of the ridge crest are used to develop a revised model of ast genesis and evolution this model helps constrain the record of intrusive and extrusive magmatism and styles of lava deposition along the ridge crest at time scales from hundreds to tens of thousands of years the grabens in the narrow ast domain 9 43 53 n are consistent with deformation above the most recent 10 diking events beneath the ridge crest frequent high effusion rate extrusive volcanism in this domain several eruptions every 100 years overprints near axis deformation and maintains a consistent ast width the most recent eruption at the ridge crest occurred in this area and did not significantly modify the physical characteristics of the ast the grabens in the wide ast domain 9 23 43 n originated with similar dimensions to the narrow ast spreading driven primarily by the intrusion of shallow dikes within a narrow axial zone causes the initial graben bounding faults to migrate away from the axis infrequent extrusive volcanism several eruptions every 1000 years fills a portion of the subsidence that accumulates over time but does not significantly modify the width of the ast outside of these domains lower effusion rate constructional volcanism without efficient drain back fills and erases the signature of the ast the relative frequency of intrusive versus extrusive magmatic events controls the morphology of the ridge crest and appears to remain constant over millennial time scales within the domains we have identified however over longer time scales 10 25 ka domain specific intrusive to extrusive ratios do not appear to be fixed in space resulting in a fairly consistent volcanic accretion over the length scale of the second order ridge segment between 9 n and 10 n

evidence of basal erosion and shearing as mechanisms contributing the development of lateral ridges in mudslides flow slides and other flow like gravitational movements abstract the origin of lateral ridges in flow like gravitational movements is controversial four examples of movements showing lateral ridge development are examined bedwellty in south wales u k la coma and gosol in the eastern pyrenees spain and los olivares in the baetic range southern spain several trenches dug in these sites showed that lateral ridges appear related to erosion of the pre existing ground surface and that shear surfaces develop at both lateral and bottom boundaries of the moving masses textural characteristics of the basal debris at bedwellty show that pre existing ground material has been incorporated within the slide material no erosion was found where lateral ridges disappear at the toe of the movements an additional mechanism is proposed to explain the origin of the lateral ridges in relation to these erosional features erosion of the pre existing ground during the downward progression of the sliding or flowing mass contributes to both the generation and isolation of lateral ridges as the outer edges of the flowing mass move more slowly than the main mass they become progressively detached either basal erosion or failure of the ground causes the subsidence of the surface of the moving mass leaving the outer boundary materials as abandoned standing lateral ridges this mechanism of lateral ridge generation may occur simultaneously with other mechanisms in the examples presented here however the amount of basal erosion and the fact that ridges are only present where erosion occurs suggest that subsidence of the whole moving mass due to ground erosion or shearing is a critical factor for the ridge development

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

preeruptive flow focussing in dikes feeding historical pillow ridges on the juan de fuca and gorda ridges linear hummocky pillow mound volcanism dominates at slow and intermediate spreading rate mid ocean ridges volcanic hummocks are thought to be formed by low effusion rates or as a result of flow focussing during effusive fissure style eruptions in which the initial dike intercepts the seafloor and erupts along its entire length in this study high resolution autonomous underwater vehicle auv bathymetry is used to accurately map the extents of four historical fissure eruptions of the juan de fuca and gorda ridges on the north gorda north cleft and coaxial ridge segments the four mapped eruptions take the form of pillow mounds which are similar in both lithology and dimension to hummocks on the mid atlantic ridge pillow mounds may be isolated or coalesce to form composite mounds aligned as ridges or as clustered groups in three of the four mapped sites the eruptions were discontinuous along their lengths with pillow mounds and composite mounds commonly separated by areas of older seafloor this style of discontinuous eruption is inconsistent with typical en echelon fissure eruptions and is probably due to a mildly overpressured fingering dike intersecting the seafloor along parts of its length

tectonic evolution of the ne palmyride mountain belt syria the bishri crustal block investigation of the bishri block centrally positioned amid the diverse tectonic and structural zones of syria reveals details of the intraplate phanerozoic development of the northern arabian platform the bishri block is a broad ne plunging inverted basin located at the ne portion of the palmyride mountain belt where the mountains intersect the euphrates fault system well and seismic data show that subsidence and sedimentation in the bishri area was generally continuous from carboniferous to paleocene time with the bishri block part of the extensive palmyride sinjar trough major bounding faults and a rift type environment are documented in the permo triassic jurassic and cretaceous the present bishri structural and topographic high has been formed through transpressive structural inversion since the mid miocene high angle mesozoic bounding normal faults now have net reverse offsets with a significant dextral strike slip component east of the bishri block towards the euphrates fault system nnw sse striking normal faults exhibit less reverse movement this deformation history correlates with the opening and closing of the nearby neotethys ocean that has driven the evolution of intracontinental syria

numerical assessment of the effects of end restraints and a pre existing fissure on the interpretation of triaxial tests on stiff clays conventional laboratory triaxial tests apply axisymmetric boundary conditions to a cylindrical sample which has an axisymmetric geometry for a homogeneous sample this implies that the deformed sha

upper crustal velocity structure and basement morphology beneath the intracontinental palmyride fold thrust belt and north arabian platform in syria an edited version of this paper was published in geophysical journal international by blackwell publishing copyright 1993 blackwell publishing see also http www blackwellpublishing com journal asp ref 0956 540xs http atlas geo cornell edu syria seber gji 1993 htm

stratigraphy and structure of eastern syria across the euphrates depression abstract a n s crustal scale geotransect across the northern arabian platform in eastern syria reveals an alternating series of basement uplifts and basins separated by predominantly transpressional fault zones above an effectively uniform crust four major tectonic provinces are crossed along a 325 100 km corridor that extends from the iraqi border in the south to the turkish border in the north the rutbah uplift the euphrates depression the abd el aziz structural zone and the qamichli uplift these features are the manifestations of reactivated pre cenozoic structures that responded to forces acting along nearby arabian plate boundaries particularly cenozoic convergence and collision along the margins of the northern arabian platform i e the bitlis suture and the east anatolian fault in southern turkey and the zagros suture in iran and iraq the database for this study consists of 3000 km of industry seismic reflection data 28 exploratory wells and geologic and bouguer gravity maps the deep crustal structure and in part the basement geometry along this transect are inferred from two dimensional modeling of bouguer gravity whereas the shallow about 8 km structure is constrained primarily by well and seismic data features of the geotransect reveal 1 1 a relatively uniform crustal column approximately 37 km thick with only minor crustal thinning beneath the euphrates crustal thinning may be slightly more pronounced beneath the euphrates about 35 km to the southeast of the transect where the bouguer gravity anomaly is slightly higher 2 2 along the euphrates depression ongoing subsidence which began during the late cretaceous resulted in the deposition of at least 3 km of late cretaceous and cenozoic rocks the structural complexity of the paleozoic and most of the mesozoic sedimentary sections along the transect contrasts markedly with a relatively simple flat lying cenozoic section along most of the transect a notable exception is the abd el aziz uplift where cenozoic rocks are strongly deformed 3 3 while euphrates subsidence continued throughout the cenozoic the inversion of the e w trending abd el aziz structure into a fault bounded tilted block began in the miocene perhaps as a response to the last episode of intense miocene collision along the nearby bitlis and zagros suture zones

a braided strike slip model for the northern continuation of the dead sea fault and its implications for levantine tectonics abstract the assumption that the 100 110 km sinistral displacement on the dead sea fault is transmitted northwards along a single structure the yammouneh fault which runs ne sw across lebanon is here reviewed a number of valid objections to this concept exist a more attractive model supported by the limited data available from the area is that the motion is transmitted along a number of faults on this basis the temporary rightward flexure of the levant fracture through lebanon has given rise to a braided strike slip fault complex the yammouneh serrhaya fault system this model overcomes the objections against the older concept and allows the explanation of the mt lebanon bekaa valley anti lebanon complex in terms of transpressive and transtensive blocks a tentative outline of the cenozoic structural evolution of the area in terms of two or more phases of motion along the levant fracture is presented

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

structure and evolution of the petroliferous euphrates graben system southeast syria the northwest trending euphrates graben system is an aborted intracontinental rift of late cretaceous age that has subsequently been hidden by cenozoic burial approximately 100 km wide the system comprises an extensive network of grabens and half grabens extending some 160 km from the anah graben in western iraq to the palmyride fold belt in central syria where it becomes more subdued the youngest prerift rocks are presently at a maximum depth of about 5 km based primarily on interpretation of 1500 km of seismic reflection profiles and data from 35 wells we mapped a complex network of numerous branching normal and strike slip faults generally striking northwest and west northwest both branched and single strand linear normal faults of generally steep dip as well as positive and negative flower structures are manifest on seismic sections no single rift bounding fault is observed instead a major flexure coupled with minor normal faulting marks the southwestern edge of the basin with considerable variation along strike to the northeast deformation diminishes on the rawda high near the iraqi border the euphrates graben system likely formed in a transtensional regime with active rifting primarily restricted to the senonian and with an estimated maximum extension of about 6 km minor cenozoic inversion of some structures also is evident approximately 30 oil fields have been discovered in the euphrates graben system since 1984 recoverable reserves discovered to date reportedly exceed 1 billion barrels of oil and lesser amounts of gas light oil is primarily found in lower cretaceous sandstone reservoirs juxtaposed by normal faulting against upper cretaceous synrift sources and seals