structural evolution of the latakia ridge and cyprus basin at the front of the cyprus arc eastern mediterranean sea abstract the active deformation front between the african and anatolian plates in the eastern mediterranean is delineated by the cyprus arc present plate kinematic vectors and earthquake data suggest that the movement along the eastern extent of the cyprus arc is largely sinistral strike slip it is however widely accepted that subduction took place beneath cyprus until the early miocene subduction has since thought to have become impeded by the collision of the eratosthenes seamount with the island of cyprus the deformation front of the cyprus arc is dominated by the latakia ridge a steep narrow high which merges gradually with the lower slope of the broad hecataeus rise in the west and extends to the northern levantine coast in the east where the expression of the ridge changes to a number of narrow northeast trending ridges and basins the latakia ridge has previously been interpreted as either a thrust culmination or a positive flower structure this study uses high resolution marine seismic reflection profiles to delineate the stratigraphic and structural architecture of the deformation front from seismic profiles four stratigraphic units bounded by major basin wide unconformities can be identified these units are eocene lower miocene miocene uppermost miocene messinian and pliocene quaternary the timing of deformation determined from growth stratal architectures on the flanks of the major structures show that two main phases of deformation characterize the structural history of the deformation front each of these phases represents a different kinematic regime a compressional regime dominated during the miocene whereas a strike slip regime dominated in the pliocene quaternary

melange genesis and ophiolite emplacement related to subduction of the northern margin of the tauride anatolide continent central and western turkey the tauride anatolide continent stretching for c 900 km across western and central turkey is one of the world s best example of a subducted exhumed passive margin within a collisional orogen twelve widely separated areas were studied and correlated to develop a new plate tectonic model a metamorphosed rifted continental margin of triassic lower cretaceous age tauride anatolide platform is overlain by upper cretaceous cenomanian lower maastrichtian pelagic sediments and then by both tectonic melange subduction complexes and sedimentary melange foredeep gravity complexes the melanges are overthrust by unmetamorphosed ophiolitic rocks commonly peridotites with swarms of diabase gabbro dykes and are underlain by metamorphic soles new geochemical evidence from basaltic blocks in the melange indicates predominantly subduction influenced within plate and mid ocean ridge type settings the dykes cutting the ophiolites were probably intruded during early stage intra oceanic arc genesis the metamorphosed continental margin melanges and ophiolites in the north anatolides are correlated with unmetamorphosed equivalents in the taurides further south e g beysehir and lycian nappes oceanic crust of triassic late cretaceous age formed between the gondwana related tauride anatolide continent in the south and the eurasia related sakarya microcontinent in the north following late triassic early cretaceous passive margin subsidence the continental margin was covered by cenomanian turonian pelagic carbonates c 98 90 ma ophiolites formed in an intra oceanic subduction zone setting in response to northward subduction probably within a two stranded ocean with the inner tauride ocean in the se and the izmir ankara erzincan ocean in the north nw metamorphic soles relate to intra oceanic subduction c 95 90 ma oceanic sedimentary igneous rocks accreted to the advancing supra subduction oceanic slab the tauride anatolide continental margin then underwent diachronous collision with the trench c 85 ma deeply subducted and metamorphosed at hp lt c 80 ma accretionary ophiolitic and exhumed hp lt rocks were gravity reworked into a southward migrating flexural foredeep and progressively overridden c 70 63 ma slices of the upper part of the platform and its margin detached and were thrust southwards as the tauride lycian and beysehir nappes together with regional scale ophiolites the continental margin and melange were simultaneously exhumed during maastrichtian early paleocene 70 63 ma and transgressed by shallow water sediments beginning in the late maastrichtian in the east c 64 ma and the mid late paleocene c 60 ma further west remnant oceanic crust was consumed during early cenozoic time followed by mid eocene 45 40 ma diachronous continental collision and a second phase of regional deformation rather than being progressive there were two stages of collision first upper cretaceous ophiolite emplacement driven by continental margin subduction trench collision and secondly eocene collision of the tauride and sakarya eurasian continents

model for the origin of the troodos massif cyprus and other mideast ophiolites any comprehensive model for the origin of the troodos complex and other mideast ophiolite complexes must explain the geochemical evidence for subduction zone involvement the thin inferred oceanic crust the extensional environment indicated by sheeted dikes the existence of fault zones perpendicular to the inferred spreading axes and the discontinuous nature of ophiolite exposures around the arabian block the andaman sea region of the indian ocean may provide an actualistic model for the origin of these ophiolites there spreading takes place in short segments above a subduction zone in the region of active spreading the andaman sea model substantially accounts for the known geologic and geophysical data from the circum arabian ophiolite belt and it leads to some predictions about the structural and geophysical relationships to be expected in this important belt the model also predicts that andaman sea spreading center magmas may be similar in composition to those found in the mideast ophiolites

spreading structure of the troodos ophiolite cyprus some paleomagnetic constraints it has been suggested that grabens on the northern flank of the troodos ophiolite formed by listric faulting in an oceanic environment and represent axial valleys fossilized by ridge jumping this paleomagnetic survey of the solea graben was carried out to constrain the structural interpretation an analysis was devised which restores both the dikes sampled to vertical and the primary remanent magnetizations to a previously derived structurally corrected remanent magnetization direction typically two solutions for the original dike orientation and the pole and angle of net rotation are obtained for each dike sampled these solutions can be separated if a locally consistent original dike strike is assumed reasons are discussed for the selection of the solution that gives an original northwesterly dike strike results are consistent with a graben rotations are up to 78 at the sites studied rotation vectors are subhorizontal and subparallel to the original dike strike suggestive of an axial process for the development of the structure however on the basis of field observations an alternative mode of origin is proposed invoking ephemeral extreme upper crustal extension by listric faulting on the west flank of an intermediate to fast spreading axis the grabens being formed by antithetic faulting

spreading structure of the troodos ophiolite cyprus orientations of dikes within the sheeted dike complex of the troodos ophiolite reveal primary spreading structure produced at a complex ridge transform intersection three structural grabens are defined by listric and planar normal faults and rotated dikes that dip symmetrically toward graben axes faults flatten at depth into a detachment within the upper parts of the plutonic complex large exhalative massive sulfide deposits occur within the pillow sections of two of the grabens and appear to be associated with underlying altered and mineralized normal fault zones that channeled hydrothermal fluids we suggest that the grabens are fossil axial valleys produced by successive eastward jumps of an approximately north trending present coordinates slow spreading ridge crest a simple model for ridge migration indicates eastward jumps of 8 13 km changes in ridge orientation are suggested by changes in trends of dikes and graben axes comparison of the pattern of dikes near the arakapas fault zone with the structure of active ridge transform intersections suggests that the fault is a right offset sinistral transform in contrast to earlier models in which a ridge to the west of the exposed troodos complex was proposed

segmented african lithosphere beneath the anatolian region inferred from teleseismic p wave tomography summary lithospheric deformation throughout anatolia a part of the alpine himalayan orogenic belt is controlled mainly by collision related tectonic escape of the anatolian plate and subduction roll back along the aegean subduction zone we study the deeper lithosphere and mantle structure of anatolia using teleseismic finite frequency p wave traveltime tomography we use data from several temporary and permanent seismic networks deployed in the region approximately 34 000 p wave relative traveltime residuals measured in multiple frequency bands are inverted using approximate finite frequency sensitivity kernels our tomograms reveal segmented fast seismic anomalies beneath anatolia that corresponds to the subducted portion of the african lithosphere along the cyprean and the aegean trenches we identify these anomalies as the subducted aegean and the cyprus slabs that are separated from each other by a gap as wide as 300 km beneath western anatolia this gap is occupied by slow velocity perturbations that we interpret as hot upwelling asthenosphere the eastern termination of the subducting african lithosphere is located near the transition from central anatolia to the eastern anatolian plateau or arabian eurasian collision front that is underlain by large volumes of hot underplating asthenosphere marked by slow velocity perturbations our tomograms also show fast velocity perturbations at shallow depths beneath northwestern anatolia that sharply terminates towards the south at the north anatolian fault zone nafz the associated velocity contrast across the nafz persists down to a depth of 100 150 km hence our study is the first to investigate and interpret the vertical extent of deformation along this nascent transform plate boundary overall the resolved upper mantle structure of anatolia is directly related with the geology and tectonic features observed at the surface of the anatolian plate and suggest that the segmented nature of the subducted african lithosphere plays an important role in the evolution of anatolia and distribution of its tectonic provinces

the cilicia adana basin complex eastern mediterranean neogene evolution of an active fore arc basin in an obliquely convergent margin abstract detailed interpretation of multi channel seismic reflection profiles showed that the deposition of the miocene successions in the cilicia adana basin complex occurred within a foredeep south of the arcuate tauride fold thrust belt the misis kyrenia fault zone defined the northernmost of a number of smaller thrust culminations developed within this foredeep fluvio deltaic successions suggest that the adana and inner cilicia basins became emergent during the tortonian when the western portion of the piggy back basin retained a marine connection the entire region became emergent during the messinian salinity crisis and up to 1000 m of evaporites were deposited in the cilicia and southern adana basins stratigraphic and structural relationships demonstrated that the late plio quaternary cilicia adana basin complex evolved as an asymmetric piggy back basin on the hanging wall of the large south verging misis kyrenia thrust culmination on the misis kyrenia segment of the culmination thrust activity ceased in early messinian whereas on the kyrenia segment it continued to the present the shift in the kinematics is expressed by the development of the ne sw trending steep faults with extensional separations bounding the plio quaternary depocentre in the adana and inner cilicia basins these basement rooted faults are incompatible with the contractional regime that existed in this part of the basin complex during the miocene in the outer cilicia basin the incompatibility between a domain of continued south directed fold thrust activity and uplift on the kyrenia range and a domain of extension associated with the development of plio quaternary depocentre indicates that strain is strongly partitioned across the e w trending southern basin bounding fault system along the southern margin of the outer cilicia basin progressive westward displacement of the tauride block within the aegean anatolian microplate created a localised transtensional regime within the inner cilicia and adana basins suggesting the presence of hard intra plate fault boundaries centred along the misis kyrenia horst block and the southern basin bounding fault system the northern basin bounding fault system including the kozan fault in the cilicia basin is a set of large antithetic structures linked to the master faults the westward pull out of the tauride block is related to the overall westward escape of the aegean anatolian microplate during the latest miocene to early pliocene whereas the continued contraction south of the basin complex across cyprus is related to the evolving collision and under plating of the continental micro fragment the eratosthenes we propose that the southern master fault of the outer cilicia basin primarily functions as a boundary separating a contractional microplate domain to the south from a transtensional microplate domain to the north

biostratigraphy of the supra ophiolite sediments of the troodos massif cyprus the cretaceous perapedhi kannaviou moni and kathikas formations the troodos massif of cyprus exposes a classic and much studied ophiolite sequence representing oceanic crust of late cretaceous age k ar dating of the sheeted dykes and of the overlying pillow lavas gives a range of 83 3 ma earliest campanian and 75 5 ma late campanian respectively for the formation of the upper levels of the ophiolite an autochthonous sequence of late cretaceous to recent age sediments is exposed resting on the ophiolite the oldest part of which reflects sedimentation in an apparently deep marine oceanic setting little biostratigraphical information is available to constrain the chronostratigraphy of these sediments in relation to the complex geological history of the island including the uplift and unroofing of the ophiolite despite their richness in microfauna and flora this paper provides an integrated biostratigraphical study based on radiolaria planktonic foraminifera and calcareous nannofossils of the oldest part of the supra ophiolite succession of the cretaceous perapedhi kannaviou moni and kathikas formations for the first time well defined micropalaeontological evidence establishes the relative ages of these formations the umbers of the perapedhi formation are no younger than campanian in age while the volcaniclastic sediments of the kannaviou formation were also deposited during campanian times the matrix of the moni formation contains a microfauna consistent with the hypothesis that it is derived from the kannaviou in contrast the kathikas formation is composed of sediment derived mainly from the allochthonous mamonia complex but autochthonous pelagic interbed horizons demonstrate that it was deposited probably within a very short time interval during the late maastrichtian key index species are figured including the first published micrographs of cretaceous planktonic foraminifera from cyprus

late miocene surface uplift of the southern margin of the central anatolian plateau central taurides turkey the timing and pattern of surface uplift of miocene marine sediments capping the southern margin of the central anatolian plateau in southern turkey provide a first order constraint on possible mechanisms of regional uplift nannofossil ostracod and planktic foraminifera biostratigraphy of the basyayla section mut ermenek basin within the mut and koselerli formations suggests a tortonian age for marine sediments unconformably capping basement rocks at 2 km elevation the identification of biozone mmi 12a 7 81 8 35 ma from planktic foraminifera in the upper part of the section provides the tightest constraint on the age which is further limited to 8 35 8 108 ma as a result of the reverse polarity of the collected samples chron 4r 1r or 4r 2r this provides a limiting age for the onset of surface uplift at the margin of one of the world s major orogenic plateaus from which an average uplift rate of 0 24 0 25 mm yr can be calculated subhorizontal beds of the uppermost marine sediments exposed throughout the mut ermenek basin suggest minimal localized deformation with just minor faulting at the basin margin and broad antiformal deformation across the basin this implies that the post 8 ma uplift mechanism must be rooted deep within the crust or in the upper mantle published pn wave velocity data for the region are compatible with topography compensated by asthenosphere across the southern margin of the plateau showing a close match to the highest topography when elevations are filtered with a 100 km wide smoothing window uplift along the southern margin of the central anatolian plateau is also reflected by the pattern of miocene marine sediments capping the margin which form an asymmetric drape fold over the topography these observations together with tomographic evidence for slab steepening and break off beneath the eastern anatolian plateau suggest that at least some of the 2 km of post 8 ma uplift of the southern central anatolian plateau margin is compensated by low density asthenospheric mantle that upwelled following slab break off

surface expression of eastern mediterranean slab dynamics neogene topographic and structural evolution of the southwest margin of the central anatolian plateau turkey 1 the southwest margin of the central anatolian plateau has experienced multiple phases of topographic growth including the formation of localized highs prior to the late miocene that were later affected by wholesale uplift of the plateau margin our new biostratigraphic data limit the age of uplifted marine sediments at the southwest plateau margin at 1 5 km elevation to 7 17 ma and regional lithostratigraphic correlations imply that the age is 6 7 ma single grain ca tims u pb zircon analyses from a reworked ash within the marine sediments yield dates as young as 10 6 ma indicating a maximum age that is consistent with the biostratigraphy our structural measurements within the uplifted region and fault inversion modeling agree with previous findings in surrounding regions with early contraction followed by strike slip and extensional deformation during uplift focal mechanisms from shallow earthquakes show that the extensional phase has continued to the present broad similarities in the change in the tectonic stress regime after 8 ma and the onset of surface uplift after 7 ma imply that deep seated process es caused post 7 ma uplift the geometry of lithospheric slabs beneath the plateau margin pliocene to recent alkaline volcanism and the uplift pattern with accompanying normal faulting point toward slab tearing and localized heating at the base of the lithosphere as a probable mechanism for post 7 ma uplift of the southwest margin considering previous work in the region there appears to be an important link between slab dynamics and surface uplift throughout the anatolian plateau s southern margin

record of cenozoic sedimentation from the amanos mountains southern turkey implications for the inception and evolution of the arabia eurasia continental collision abstract the sedimentary succession of the southern amanos mountains bordering the eastern margin of the karasu rift in south central turkey provides a record of environmental change from the eocene lutetian to the upper miocene tortonian that charts the final evolution of the northern margin of the arabian plate prior to and during continental collision eocene shallow marine carbonates hacidagi formation are interpreted as the youngest unit of the arabian passive margin succession deposited on a northwards facing carbonate ramp subsequent deformation and uplift took place during the oligocene represented by folding of the eocene and older strata this is interpreted to be the result of initial continental collision between arabia and eurasia unconformably overlying the eocene limestone are lower miocene conglomerates sandstones and palaeosols up to 150 m thick kici formation these were deposited in a range of marginal marine settings consisting of alluvial fan fan delta facies flood plain as well as basinal facies subsequently during the middle miocene local patch reefs developed in restricted areas kepez formation followed by upper miocene sediments gokdere formation composed of relatively deep water hemipelagic marl with clastic interbeds which represent a transgression during this period the upper miocene becomes sandier upwards this records the regression from the relatively deep water facies to coastal sediments water depth gradually became shallower until during pliocene time the area became continental in nature by the quaternary rifting had resulted in the development of the karasu rift with active alluvial fans along the margins and braided rivers depositing coarse conglomerates in the axial zone these conglomerates are interbedded with basaltic lava flows that resulted from the region extension across the area this research shows that initial continental collision occurred in this area after the lutetian 40 4 ma and before the aquitanian 23 03 ma supporting the hypothesis that the southern neotethys ocean closed during the late eocene to oligocene this was a time of climatic change including the onset of southern hemisphere glaciation in which the closure of the southern neotethys may have had played an important role

geochemistry and timing of post metamorphic dyke emplacement in the mersin ophiolite southern turkey new age constraints from40ar 39ar geochronology the mersin ophiolite which is a relic of the late cretaceous neotethyan ocean domain in the eastern mediterranean is situated on the southern flank of the central tauride belt the ophiolite body is cross cut at all structural levels by numerous mafic dyke intrusions the dykes do not intrude the underlying melange of platform carbonates therefore dyke emplacement post dates the formation of the opholite and metamorphic sole but pre dates the final obduction onto the tauride platform the post metamorphic dyke swarms suggest the geochemical characteristics of island arc tholeiites iat 40ar 39ar geochronology of the post metamorphic microgabbroic diabasic dykes cutting both mantle tectonites and metamorphic sole revealed ages ranging from 89 6 0 7 63 8 0 9 myr old respectively indicating widespread magmatic activity during the late cretaceous early palaeocene in the neotethyan ocean these data suggest that island arc development in the neotethyan ocean in southern turkey was as early as late cretaceous

tectonic map and geologic evolution of syria the role of gis this paper was published in the journal the leading edge by the society of exploration geophysicists seg retains the copyright to this paper see also http www edge online org http atlas geo cornell edu syria brew tle 2000 html

palaeomagnetic evidence for clockwise rotations related to dextral shear along the southern troodos transform fault cyprus abstract the southern troodos arakapas fault represents a late cretaceous oceanic fracture zone which was locally disrupted during late cretaceous eocene palaeorotation of the troodos microplate opinions are divided as to the sense of displacement along the transform fault and the exact timing of initiation of palaeorotation palaeomagnetic studies of turonian zeolite facies lavas and sediments exposed within the transform domain have revealed considerable variations in the declination of remanent magnetisation between sites along the arakapas fault belt the western margin of the limassol forest complex and the eastern flank of the troodos ophiolite at seven sites clockwise rotation of fault blocks has occurred about steeply inclined axes one fault block at the western end of the arakapas fault belt has experienced a net anticlockwise rotation while at six other sites only simple tilting about sub horizontal axes is indicated the overall clockwise sense of block rotation and initial dyke strikes calculated at three sites are consistent with right lateral slip along the transform cross cutting relationships revealed by the analysis of one site demonstrate that these rotations took place during crustal genesis and are not a product of post spreading disruption of the fracture zone sites located further south in the eastern limassol forest complex show no relative rotation with respect to the main troodos ophiolite to the north and have experienced only simple tilting however if our results are considered in conjunction with existing palaeomagnetic data from the area it appears that the entire area lay within a complicated zone of localised and predominantly clockwise block rotations produced by dextral slip along the transform some areas were rotated by over 100 about steeply inclined axes whereas others experienced only simple tilting the whole area was later subjected to a bulk 90 anticlockwise rotation along with the troodos microplate data obtained from the umbers and radiolarites perapedhi fm exposed on the eastern flank of the limassol forest block indicate that at least 30 and possibly up to 45 of this 90 rotation took place over a maximum of 15 ma

serpentinization of cumulate ultramafic rocks from the north arm mountain massif of the bay of islands ophiolite abstract partially serpentinized dunites and wehrlites comprise the bulk of the cumulate ultramafic unit at the north arm mountain massif of the bay of islands ophiolite complex newfoundland in a suite of 59 dunites and werhlites from the base of the unit the serpentinized portions consist of lizardite chrysotile brucite accessory magnetite the ratio of lizardite chrysotile to brucite 8 2 weight percent petrographic observations show that most serpentinization occurred at the expense of olivine only limited amounts of clinopyroxene were serpentized an estimated volume increase of 32 accompanied serpentinization of the peridotites reconstructions of the primary modal proportions of wehrlites made taking this volume increase into account contain an average of 6 more clinopyroxene and 6 less olivine than do modal reconstructions that ignore the volume increase mass balance calculations provide no clear evidence for appreciable metasomatism of al2o3 cao feo mgo or sio2 during serpentinization the presence of brucite the evidence that most serpentinization occurred at the expense of olivine and the lack of appreciable metasomatism suggest that the primary reaction that controlled serpentinization of the peridotites is 2mg 2 sio 2 3h 2 o mg 3 si 2 o 5 oh 4 mg oh 2 olivine added serpentine brucite

origin and emplacement of the late cretaceous baer bassit ophiolite and its metamorphic sole in nw syria abstract the baer bassit ophiolite of inferred late cretaceous age was emplaced from the south tethys ocean onto the leading edge of the arabian continental margin in latest cretaceous maastrichtian time dismembered sequences in different thrust sheets can be correlated to produce a complete ophiolite sequence with a metamorphic sole at the base overlain in turn by upper mantle tectonite rare cumulates massive and layered gabbros localized high level plagiogranites sheeted dykes basic extrusives and minor fe mn sediments umbers the restored ophiolite sequence is similar to that of the more intact troodos and hatay ophiolites but dissimilar to oman the baer bassit extrusives are magnesian and strongly depleted comparable to primitive island arc tholeiites and some boninitic lavas which favours a subduction related origin a well developed metamorphic sole is divisible into high grade amphibolite facies assemblages in the north and lower grade greenschist facies assemblages in the centre of the region but no complete inverted metamorphic gradient is preserved in any one local area the protoliths of both the high grade amphibolites and lower grade rocks greenschists are interpreted as alkali basalts and pelagic sediments including chert similar to the volcanic rocks in an underlying unmetamorphosed melange the metamorphic fabrics progressively evolved from ductile to brittle during tectonic transport towards the southeast most of the metamorphic fabrics evolved during intense shearing but some of the alkaline metabasites apparently were metamorphosed under relatively static strain conditions the apparent absence of preserved inverted metamorphic gradients in baer bassit may reflect a complex deformation history during emplacement alternatively differing p t conditions may be recorded at different depths at the base of the over riding mantle wedge during emplacement the front of the ophiolite was tectonically imbricated and overthrust by the main ultramafic slab bassit massif the thickest massif baer is underlain by a high grade metamorphic sole and was internally shortened but without thrust duplication of the entire ophiolite sequence following covering by late maastrichtian palaeogene marine calcareous sediments the area was subjected to mid tertiary regional folding this was followed by neogene dominantly left lateral strike slip deformation along the african eurasian plate boundary extending from south of cyprus to the dead sea transform fault as a result the originally emplaced thrust sheets were dissected into three main composite units baer bassit and the southeastern units separated by strongly faulted and sheared ophiolitic blocks and unmetamorphosed volcanic sedimentary melange

thermo mechanical modeling of the obduction process based on the oman ophiolite case obduction emplaces regional scale fragments of oceanic lithosphere ophiolites over continental lithosphere margins of much lower density for this reason the mechanisms responsible for obduction remain enigmatic in the framework of plate tectonics we present two dimensional 2d thermo mechanical models of obduction and investigate possible dynamics and physical controls of this process model geometry and boundary conditions are based on available geological and geochronological data and numerical modeling results are validated against petrological and structural observations of the oman semail ophiolite our model reproduces the stages of oceanic subduction initiation away from the arabian margin the emplacement of the oman ophiolite on top of it and the domal exhumation of the metamorphosed margin through the ophiolitic nappe a systematic study indicates that 350 400 km of bulk shortening provides the best fit for both the maximum pressure temperature conditions of the metamorphosed margin 1 5 2 5 gpa 450 600 c and the dimension of the ophiolitic nappe 170 km width our results confirm that a thermal anomaly located close to the arabian margin 100 km is needed to initiate obduction we further suggest that a strong continental basement rheology is a prerequisite for ophiolite emplacement

tectonic significance of the geochemistry and petrology of ophiolites in southeast anatolia turkey abstract the southeast anatolian ophiolites form discontinuous linear belts of oceanic fragments immediately north of the bitlis zagros suture which marks a continental collision zone between the arabian platform to the south and the taurides to the north the late cretaceous ophiolites in the southeast anatolia are represented by the kizildag in the hatay area the goksun and the berit to the north of kahramanmaras ispendere in the malatya area and komurhan guleman in the elazig area the goksun berit ispendere komurhan and guleman ophiolites were attached to the base of the tauride platform i e the malatya keban along its northern active margin and intruded by the i type calc alkaline granitoids of late cretaceous age in contrast the kizildag hatay ophiolite was thrust over the arabian passive margin in the south the cumulate rocks in the ophiolites are represented by dunite wehrlite lherzolite olivine clinopyroxenite olivine gabbronorite olivine gabbro gabbronorite and gabbro highly magnesian olivines fo88 to 74 and pyroxenes mg 95 to 60 as well as highly calcic plagioclases an95 to 68 from the cumulate rocks differ from oceanic equivalents which mainly formed from a mor basaltic melt the order of crystallization in mineral phases whole rock and mineral chemistry data from the cumulates suggest that the primary magma is compositionaly similar to that observed in modern island arc tholeiitic sequences the volcanic and subvolcanic rocks exhibit tholeiitic compositions chondrite normalized ree n morb normalized multi element patterns and tectonic discrimination diagrams suggest the existence of two main types of parental basic magmas in the crustal rocks of the se anatolian ophiolites these are i iat series that characterize the kizildag goksun ispendere komurhan and guleman ophiolites and ii low ti boninitic series known only in the kizildag ophiolite the geochemistry of the crustal rocks suggests that they formed in a suprasubduction zone tectonic setting including arc forearc environments in the southern neotethys these well preserved plutonic oceanic crustal remnants mainly exhibit an intact ophiolite pseudostratigraphy and are overlain by a volcanic sedimentary unit made up of alternations of basic to acidic extrusive rocks debris flows volcaniclastic sandstones and pelagic limestones interpreted as a tholeiitic ensimatic island arc assemblage built on the suprasubduction zone type crust the metamorphism of some of the ophiolites i e berit in the se anatolia might be related to later stages of intraoceanic subduction during the evolution of the southern neotethys

a new classification of the turkish terranes and sutures and its implication for the paleotectonic history of the region abstract the turkish part of the tethyan realm is represented by a series of terranes juxtaposed through alpine convergent movements and separated by complex suture zones different terranes can be defined and characterized by their dominant geological background the pontides domain represents a segment of the former active margin of eurasia where back arc basins opened in the triassic and separated the sakarya terrane from neighbouring regions sakarya was re accreted to laurasia through the balkanic mid cretaceous orogenic event that also affected the rhodope and strandja zones the whole region from the balkans to the caucasus was then affected by a reversal of subduction and creation of a late cretaceous arc before collision with the anatolian domain in the eocene if the anatolian terrane underwent an evolution similar to sakarya during the late paleozoic and early triassic times both terranes had a diverging history during and after the eo cimmerian collision north of sakarya the kure back arc was closed during the jurassic whereas north of the anatolian domain the back arc type oceans did not close before the late cretaceous during the cretaceous both domains were affected by ophiolite obduction but in very different ways north directed diachronous middle to late cretaceous melange obduction on the jurassic sakarya passive margin senonian synchronous southward obduction on the triassic passive margin of anatolia from this it appears that the izmir ankara suture currently separating both terranes is composite and that the passive margin of sakarya is not the conjugate margin of anatolia to the south the cimmerian taurus domain together with the beydaglari domain part of the larger greater apulian terrane were detached from north gondwana in the permian during the opening of the neotethys east mediterranean basin the drifting cimmerian blocks entered into a soft collision with the anatolian and related terranes in the eo cimmerian orogenic phase late triassic thus suturing the paleotethys at that time the taurus plate developed foreland type basins filled with flysch molasse deposits that locally overstepped the lower plate taurus terrane and were deposited in the opening neotethys to the south these olistostromal deposits are characterized by pelagic carboniferous and permian material from the paleotethys suture zone found in the mersin melange the latter as well as the antalya and mamonia domains are represented by a series of exotic units now found south of the main taurus range part of the mersin exotic material was clearly derived from the former north anatolian passive margin huglu type series and re displaced during the paleogene this led us to propose a plate tectonic model where the anatolian ophiolitic front is linked up with the samail baer bassit obduction front found along the arabian margin the obduction front was indented by the anatolian promontory whose eastern end was partially subducted continued slab roll back of the neotethys allowed anatolian exotics to continue their course southwestward until their emplacement along the taurus southern margin mersin and up to the beydaglari promontory antaya mamonia in the latest cretaceous paleocene the supra subduction ocean opening at the back of the obduction front troodos type ocean was finally closed by eocene north south shortening between africa and eurasia this brought close to each other cretaceous ophiolites derived from the north of anatolia and those obducted on the arabian promontory the latter were sealed by a maastrichtian platform and locally never affected by alpine tectonism whereas those located on the eastern anatolian plate are strongly deformed and metamorphosed and affected by eocene arc magmatism these observations help to reconstruct the larger frame of the central tethyan realm geodynamic evolution

varying tectonic control on basin development at an active microplate margin latakia basin eastern mediterranean abstract detailed interpretation of multichannel seismic reflection profiles show that the latakia basin evolved in two distinct tectonic stages southeast directed contraction that culminated in the latest miocene followed in the early middle pliocene by progressive transition to partitioned contraction and extension related to the initiation of strike slip along the eastern anatolian transform fault and its marine extensions the miocene fold thrust belt comprises two arcuate culminations enclosing a miocene piggy back depocentre situated on the backlimb of the amanos larnaka ramp anticline in the early middle miocene this piggy back basin was part of a much wider foredeep that also encompassed the miocene successions of the cilicia adana basin complex to the north the misis kyrenia fold thrust belt evolved in the tortonian effectively dividing the foredeep into two large piggy back basins our data demonstrate that a fundamental change in kinematic regime occurred during the messinian to early pliocene involving the onset of strike slip movements resulting in transtension along the northeast trending portion of the main lineaments bounding the latakia basin and continued contraction across the east trending portion of the lineaments in the northeastern portion of the latakia basin southeast directed thrusting ceased in the early messinian and was followed in the lower pliocene by the development of horst and grabzen structures bounded by faults linking onland with the strands of the east anatolian transform fault

neotethyan intraoceanic microplate rotation and variations in spreading axis orientation palaeomagnetic evidence from the hatay ophiolite southern turkey abstract insights into tectonic processes operating in ancient ocean basins are provided by analyses of fragments of oceanic lithosphere preserved as ophiolites during collisional orogenesis here we present a palaeomagnetic analysis of the upper cretaceous hatay kizil dag ophiolite of turkey that provides evidence for intraoceanic microplate rotation and variations in ridge axis orientation in a neotethyan ocean basin magnetizations at 46 sites are shown to be pre deformational in origin and rotated from the relevant reference direction a net tectonic rotation approach to the analysis of the data provides information on permissible net rotation poles and angles and allows uncertainties in input vectors to be considered results demonstrate that all levels of the ophiolite have been rotated anticlockwise by angles in excess of 90 around steeply inclined axes the hatay ophiolite formed in the same supra subduction zone spreading system as the troodos ophiolite cyprus which is known to have rotated 90 anticlockwise in an intraoceanic setting in the late cretaceous to early eocene by considering our results in the context of the known timing of the troodos rotation we infer that 50 60 of rotation of the hatay ophiolite took place as part of an areally extensive troodos microplate this phase of rotation was triggered by initial impingement of the arabian continental margin with the neotethyan subduction trench consistent with models for modern day oceanic microplate rotation in complex convergent plate boundaries the hatay ophiolite then became detached from the actively rotating microplate and was emplaced onto the arabian margin in the maastrichtian undergoing a further 30 40 of anticlockwise rotation during thrusting back stripping of rotations allows correction of the hatay sheeted dykes to their initial orientations the restored dyke trend of 020 differs from that inferred previously for the troodos sheeted dyke complex demonstrating a primary variation in orientation of neotethyan spreading axes such variability is commonly observed in modern spreading systems in marginal basins these may act as analogues for the supra subduction zone spreading inferred for many ophiolites

tectono stratigraphic evolution of the northern levant basin offshore lebanon abstract seismic interpretation constrained by a detailed assessment of the levant paleogeography allowed subdividing the sedimentary infill of the northern levant basin offshore lebanon in eight major seismic packages fifteen seismic facies have been identified with distinctive characteristics the levant basin architecture is pre determined by a late paleozoic early mesozoic rift that led to the formation of a passive margin dominant aggrading carbonate platforms are observed along the levant margin and deepwater mixed settings i e carbonates and siliciclastics are suggested to prevail in the basin the collision of afro arabia with eurasia led to the development of a flexural basin in the northernmost offshore lebanon since the late cretaceous a southward migration of this flexural depocenter in the miocene is hindered by the change in the stress field along the latakia ridge and by the westward escape of the anatolian plate in late miocene and pliocene times interplay between major geodynamic events as well as sea level fluctuations in the mesozoic and cenozoic induced important marginal uplifts and emersion sediments sourced from the erosion of nubian siliciclastic material and from the exposed granitic red sea rift shoulders and arabian shield were driven into the levant basin the sediment sources diversity the mechanisms of sediment transport through varied pathways i e the levant margin canyons the latakia region and the nile delta deep sea cone are expected to strongly impact the reservoir characteristics and prospectivity of the northern levant basin

extreme tectonic rotations within an eastern mediterranean ophiolite baer bassit syria palaeomagnetic results from 27 sites at five localities within the dismembered bae r bassit ophiolite of northern syria are presented the ophiolite forms part of a series of thrust sheets emplaced over mesozoic carbonates of the arabian platform in the middle maastrichtian a positive inclination only area wide tilt test applied to four locality mean remanences and positive fold and reversal tests from palaeohorizontal units pillow lavas lava flows within one of these localities indicate that the ophiolite preserves pre deformation magnetisations variable directions of remanence between localities demonstrate that the ophiolite has experienced extreme relative anticlockwise rotations on a kilometric scale within the most extensively sampled ophiolite massif bassit sheet there is a progressive increase in rotation from north to south the southernmost units at the lowest structural level in the imbricate thrust stack record the highest rotation exceeding 200 although tectonic rotation during imbricate thrusting has been reported in a number of orogenic belts the pattern of rotations in the bassit sheet is difficult to explain by differential thrust sheet rotation instead regional comparisons with the hatay ophiolite of southern turkey and the troodos ophiolite of cyprus suggest that a significant component of rotation may be ascribed to intraoceanic deformation of a coherent region of oceanic crust within the southern neotethyan basin prior to ophiolite emplacement the partially rotated bae r bassit ophiolite was then emplaced and structurally dismembered by thrust faulting during the late tertiary the ophiolitic units were further rotated during the initiation and development of a major sinistral strike slip fault zone linking the cyprus subduction zone to the dead sea transform system the extreme rotations observed in the study are therefore of composite origin and reflect the complex development of structural fabrics within the ophiolite 2002 elsevier science b v all rights reserved

a miocene onset of the modern extensional regime in the isparta angle constraints from the yalvac basin southwest turkey the pre neogene tauride fold and thrust belt comprising cretaceous ophiolites and metamorphic rocks and non metamorphic carbonate thrust slices in southern turkey is flanked and overlain by neogene sedimentary basins these include poorly studied intra montane basins including the yalvac basin in this paper we study the stratigraphy sedimentology and structure of the yalvac basin which has a middle miocene and younger stratigraphy our results show that the basin formed as a result of multi directional extension with ne sw to e w extension dominating over subordinate nw se to n s extension we show that faults bounding the modern basin also governed basin formation with proximal facies close to the basin margins grading upwards and basinwards into lacustrine deposits representing the local depocentre the yalvac basin was a local basin but a similar contemporaneous history recently reconstructed from the altinapa basin 100 km to the south shows that multi directional extension dominated by e w extension was a regional phenomenon extension is still active today and we conclude that this tectonic regime in the study area has prevailed since middle miocene times previously documented e w shortening in the isparta angle along the aksu thrust 100 km to the southwest of our study area is synchronous with the extensional history documented here and e w extension to its east shows that anatolian westwards push is likely not the cause synchronous e w shortening in the heart and e w extension in the east of the isparta angle may be explained by an eastwards dipping subduction zone previously documented with seismic tomography and earthquake hypocentres we suggest that this slab surfaces along the aksu thrust and creates e w overriding plate extension in the east of the isparta angle neogene and modern anatolian geodynamics may thus have been driven by an aegean antalya and cyprus slab segment that each had their own specific evolution

palaeorotation of the troodos microplate cyprus the troodos ophiolite represents one of the best preserved fragments of ocean floor crust that is exposed on land as the extrusive series of the ophiolite retains a stable magnetization that is directed westward the ocean crust is considered to have rotated anticlockwise through 90 since its formation in the late cretaceous1 to determine the timing of the rotation event over 3 000 orientated samples have been collected from the ophiolite and from its in situ turonian to recent sedimentary cover here we report that pelagic chalks immediately overlying the highest extrusive lava units of the ophiolite complex give reliable magnetic vector directions indicating that at least 60 of rotation occurred before the lower eocene and that rotation was completed by the end of the lower eocene rotation cannot have occurred within a single late miocene event as reported previously2 regional geological considerations support the rotation of only a small fragment of oceanic crust that was stranded adjacent to an active continental margin in this tectonic setting the oblique consumption of oceanic crust beneath troodos crust could provide the necessary driving force for tectonic rotation

retrodeforming the arabia eurasia collision zone age of collision versus magnitude of continental subduction the arabia eurasia collision has been linked to global cooling the slowing of africa mediterranean extension the rifting of the red sea an increase in exhumation and sedimentation on the eurasian plate and the slowing and deformation of the arabian plate collision age estimates range from the late cretaceous to pliocene with most estimates between 35 and 20 ma we assess the consequences of these collision ages on the magnitude and location of continental consumption by compiling all documented shortening within the region and integrating this with plate kinematic reconstructions shortening estimates across the orogen allow for 350 km of neogene upper crustal contraction necessitating collision by 20 ma a 35 ma collision requires additional subduction of 400 600 km of arabian continental crust using the oman ophiolite as an analogue ophiolitic fragments preserved along the zagros suture zone permit 180 km of subduction of the arabian continental margin plus overlying ophiolites wholesale subduction of this more dense continental margin plus ophiolites would reconstruct 400 500 km of postcollisional arabia eurasia convergence consistent with a ca 27 ma initial collision age this younger arabia eurasia collision suggests a noncollisional mechanism for the slowing of africa and associated extension

east anatolian high plateau as a mantle supported north south shortened domal structure an edited version of this paper was published by the american geophysical union agu copyright 2003 agu see also http www agu org pubs crossref 2003 2003gl017858 shtml http atlas geo cornell edu turkey publications sengor et al 2003 htm

the role of the kyrenia range lineament cyprus in the geological evolution of the eastern mediterranean area rewarding insights into major crustal lineaments come from the integrated study of well exposed examples one is the kyrenia range a narrow arcuate lineament of several hundred kilometres in length comprising northern cyprus and its offshore extension the kyrenia range consists mostly of mesozoic and tertiary sedimentary and subordinate volcanic and metamorphic rocks disposed in four rock groups separated by unconformities recording deformation events the lineament is dominated by a steeply dipping composite thrust pile located partly along and partly straddling the abrupt northward termination of crust similar to the troodos igneous complex at depth the 200 ma history of the lineament involved episodic rift passive margin active margin strike slip and uplift phases the area was rifted off gondwana in the late triassic to form a southerly turkish microcontinent capped by a gently subsiding carbonate platform after formation of a small ocean basin to the south during the cretaceous troodos ocean northward subduction began santonian the first major deformation d1 is attributed to pervasive dextral strike slip which removed the mesozoic passive margin and brecciated and metamorphosed the remaining platform in the maastrichtian and early tertiary the area subsided and scree breccias were shed from scarps into pelagic carbonate depositing seas while bimodal within plate type lavas were erupted in an extensional setting influenced by strike slip by mid eocene time shortening first evidence by flysch and olistostrome deposition culminated in strong southward thrusting d2 and localized metamorphism northward subduction south of cyprus ensued and the range lay in an extensional fore arc setting in late eocene and miocene time the area then subsided dramatically and accumulated thick turbidite sequences derived from eroding tauride mountain areas to the northeast faulting and general uplift in the late miocene was followed by renewed compressional deformation climaxing in mid pliocene time d3 with large scale thrusting and tilting pulsed vertical uplift continued through the quaternary similar volcanic and metamorphic rocks formed along the kyrenia lineament at intervals sedimentary rocks emerge as the most sensitive tectonic setting indicators long lived lineaments like the kyrenia range are inherently very complicated and perceived simple solutions in other cases should be viewed with some scepticism

late eocene neogene sedimentary geology of the girne kyrenia range northern cyprus a case history of sedimentation related to progressive and diachronous continental collision abstract sedimentary geology can shed light on the processes of continental collision the easternmost mediterranean provides an exceptional opportunity to study sediments deposited during progressive and diachronous continental collision with implications for comparable settings elsewhere here we focus on sediment sources pathways and deposition of mostly deep sea clastic sediments exposed in northern cyprus the sedimentary basin forms part of the northern continental margin of the southern neotethys ocean and is represented by a ca 200 km long e w trending arcuate lineament encompassing northern cyprus and its submarine link with turkey the upper eocene upper miocene basin was divided into northerly and southerly sub basins during mid to late miocene time by an e w trending inferred syn depositional fault lineament the sequence begins with non marine to shallow marine basal conglomerates late eocene that abruptly fine upwards into siliciclastic turbidites oligocene followed by biogenic calciturbidites and marls aquitanian langhian during mid late miocene the northerly sub basin was characterised by thin to medium bedded calciturbidites and marls serravallian overlain by thick bedded medium grained lithic sandstones tortonian in contrast the southern sub basin is dominated by siliciclastic turbidites with abundant sole structures burdigalian tortonian palaeocurrent evidence indicates dominantly westward sediment transport especially during the late miocene the serravallian tortonian sandstones of the northern sub basin are relatively rich in carbonates while the southern sub basin contains more siliciclastic and ophiolite derived detritus indicating differences in sediment supply in general the upper eocene basal conglomerates were mainly derived from the north from within the girne kyrenia range and its inferred northward extension in response to rapid subsidence reflecting possible southward subduction zone retreat clastic sediment sources to the north then submerged while clastic sediment was instead mainly supplied from the south neotethyan suture zone to the east and northeast in southern turkey reflecting diachronous collision deep water deposition persisted in the easternmost mediterranean basin further west until this was terminated in northern cyprus by thrusting folding during latest miocene earliest pliocene quaternary collision related uplift ensued similar sedimentary development is to be expected in collisional settings elsewhere e g tethyan closure in the himalayas iapetus closure in the appalachians

tectonic framework and late cenozoic tectonic history of the northern part of cyprus implications for earthquake hazards and regional tectonics abstract located near the triple junction of the african arabia and eurasian plate cyprus has had an active and complex neotectonic history which includes devastating historical earthquakes investigations into the tectonic framework of the northern part of cyprus provide important insights into regional tectonism of the eastern mediterranean and middle east the northern part of cyprus is divided into two tectono stratigraphic terranes the boundary of which is the ovgos fault zone in the middle miocene the ovgos fault zone was a marine platform margin which separated open marine platform carbonates from deep marine turbidites transpressive movement along easterly and northeasterly trending structures dominated the late miocene deposition and preservation of messinian evaporites occurred in grabens at intersections of these trends n s compression began in the early pliocene and produced contractional tectonism along east west trends including major thrusting of allochthonous rocks in the kyrenia range quaternary deformation has been dominated by strike slip faults along northeast and northwest trends movement during the pleistocene occurred on several of these faults holocene movement is documented on one of these faults a seismic hazard is implied for the nicosia area because its proximity to the quaternary faults since the miocene cyprus has been continuously uplifted but the tectonic setting is controversial as some researchers invoke a subduction zone setting and others ascribe to a regime of strike slip tectonics our neotectonic framework is consistent with a restraining bend model for cyprus in a regional strike slip regime

structural development of the central kyrenia range north cyprus in its regional setting in the eastern mediterranean region a detailed structural analysis of the mesozoic cenozoic geological development of the central segment of the kyrenia range in its regional tectonic context is given here the structural evidence comes from five structural traverses outcrop observations small scale structures and related regional evidence the majority of the structures are fault planes of which a subordinate number exhibit slickenlines fault plane data n 2688 with kinematics n 537 additional kinematic data were obtained from c s fabrics and folds small scale structures in each stratigraphic unit were backstripped to reveal relative chronology synthesis of the structural information indicates three phases of convergence related deformation 1 late cretaceous associated with greenschist facies metamorphism followed by exhumation that was probably associated with wnw ese to ene wsw trending high angle faulting 2 mid eocene associated with southward thrusting coupled with n s strike slip transfer faulting and oblique faulting in an overall sinistral transpressive stress regime 3 late miocene earliest pliocene involving southward thrusting and folding localised back thrusting extensive fault reactivation and large scale segmentation of the range intense uplift of the kyrenia range took place during the plio pleistocene possibly related to the collision of the eratosthenes seamount with the cyprus trench to the south of the island the three main convergent phases relate to stages of northward subduction and diachronous continental collision affecting the northerly active continental margin of the southern neotethys

high pressure metasediments in central turkey constraints on the neotethyan closure history 1 the distribution of oceanic domains and continental blocks in central anatolia remains a challenge in understanding the alpine geodynamic evolution of the tethys realm the consumption of a neotethys oceanic branch at the mesozoic cenozoic boundary welded the central anatolian crystalline complex in central turkey and the anatolide tauride block in western turkey with the northerly eurasian margin whether those two regions constituted a single or two distinct continental masses is still matter of debate high pressure metamorphism has been locally evidenced in the afyon zone which was however defined as a greenschist facies metamorphic zone of the anatolide tauride block since the afyon zone composes a metamorphic equivalent of a continental margin exposed far south of the izmir ankara suture zone this encouraged us to reevaluate its metamorphic evolution in order to better understand the relation between western and central turkey our investigations reveal that the high pressure minerals fe mg carpholite and glaucophane are present in the entire afyon zone which we reconsider as a blueschist facies zone we additionally present a tectonic reconstruction stripping off the postcollisional tectonics it reveals that today s bending of the high pressure belt is consistent with an eocene collision of the anatolide tauride block around the southern edge of the central anatolian crystalline complex we argue that the central anatolian crystalline complex and the anatolide tauride block were two distinct continental masses separated by a neotethyan oceanic stripe the closure of which engendered subduction related metamorphism in the latter and arc volcanism and high grade metamorphism in the former by late cretaceous to early cenozoic

accelerated subsidence and sedimentation in the levant basin during the late tertiary and concurrent uplift of the arabian platform tectonic versus counteracting sedimentary loading effects 1 since the middle eocene the northwest arabian platform has been emerging from the water and rising above sea level whereas the adjacent levant basin has been subsiding and accumulating a thick sedimentary section this study investigates these opposing vertical motions and the relative roles of tectonic driven versus isostatic adjustment forces involved such a distinction is strongly dependent on a reliable estimation of the paleobathymetry which in pelagic environments may vary substantially we use two different methods to estimate the paleo water depth in the deep levant basin in the tertiary time isostatic balancing calculations with the adjacent inland region are employed to estimate the paleo water depth in the deep levant basin in the middle eocene just before the commencement of the late tertiary tectonic phase for later periods we use morpho structural elements such as abrasion surfaces and incised canyons to build laterally changing topo bathymetry profiles our results indicate that in the mid eocene water depth in the deep levant basin was 2 3 5 km which gradually decreased to 1 5 km today based on these results our analysis shows that the enhanced subsidence of the levant basin reflects an isostatic response to sedimentary filling of a pre existing deep water basin with no involvement of a downward tectonic force on the contrary we suggest that the regional tectonic force was upward counteracting a sedimentary loading effect further regional implication of this understanding is that the cause for uplifting and exposure of the nw arabian platform in the late tertiary extended far westward beyond the inland region

multi phased uplift of the southern margin of the central anatolian plateau turkey a record of tectonic and upper mantle processes abstract uplifted neogene marine sediments and quaternary fluvial terraces in the mut basin southern turkey reveal a detailed history of surface uplift along the southern margin of the central anatolian plateau from the late miocene to the present new surface exposure ages 10be 26al and 21ne of gravels capping fluvial strath terraces located between 28 and 135 m above the goksu river in the mut basin yield ages ranging from ca 25 to 130 ka corresponding to an average incision rate of 0 52 to 0 67 mm yr published biostratigraphic data combined with new interpretations of the fossil assemblages from uplifted marine sediments reveal average uplift rates of 0 25 to 0 37 mm yr since late miocene time starting between 8 and 5 45 ma and 0 72 to 0 74 mm yr after 1 66 to 1 62 ma together with the terrace abandonment ages the data imply 0 6 to 0 7 mm yr uplift rates from 1 6 ma to the present the different post late miocene and post 1 6 ma uplift rates can imply increasing uplift rates through time or multi phased uplift with slow uplift or subsidence in between longitudinal profiles of rivers in the upper catchment of the mut and ermenek basins show no apparent lithologic or fault control on some knickpoints that occur at 1 2 to 1 5 km elevation implying a transient response to a change in uplift rates projections of graded upper relict channel segments to the modern outlet together with constraints from uplifted marine sediments show that a slower incision uplift rate of 0 1 to 0 2 mm yr preceded the 0 7 mm yr uplift rate the river morphology and profile projections therefore reflect multi phased uplift of the plateau margin rather than steadily increasing uplift rates multi phased uplift can be explained by lithospheric slab break off and possibly also the arrival of the eratosthenes seamount at the collision zone south of cyprus

linking slab break off hellenic trench retreat and uplift of the central and eastern anatolian plateaus abstract the central and eastern anatolian plateaus are integral parts of the world s third largest orogenic plateau in the past decade geophysical surveys have provided insights into the crust lithosphere and mantle beneath eastern anatolia these observations are now accompanied by recent surveys in central anatolia and new data constraining the timing and magnitude of uplift along its northern and southern margins together with predictions from geodynamic models on the effects of various processes on surface deformation and uplift the observations can be integrated to identify probable mechanisms of anatolian plateau growth a changeover from shortening to extension along the southern margin of central anatolia that is coeval with the start of uplift can be most easily associated with oceanic slab break off and tearing this interpretation is supported by tomography deep seismicity or lack thereof and gravity data based on the timing of uplift geophysical and geochemical observations and model predictions slab break off likely occurred first beneath eastern anatolia in middle to late miocene time and propagated westward toward cyprus by the latest miocene alternatively the break off near cyprus could have occurred in late pliocene to early pleistocene time in association with collision of the eratosthenes seamount continental fragment with the subduction zone uplift at the northern margin of central anatolia appears to result from crustal shortening starting in the late miocene or early pliocene which has been linked to the broad restraining bend of the north anatolian fault the uplift history of the interior of central anatolia since the late miocene is unclear although shortening there appears to have ended by the late miocene followed by ne sw extension this change in the deformation style broadly coincides with faster retreat of the hellenic trench as well as uplift of the northern and southern margins of central anatolia these different events throughout the plateau may be linked as faster retreat of the hellenic trench has been predicted to occur after slab break off which could have induced extension of central anatolia and helped to form the north anatolian fault through accelerated westward movement of anatolia relative to eurasia correlative geochronologic evidence that we summarize here supports the hypothesis that the geodynamic activity throughout the aegean anatolian domain starting in latest miocene to early pliocene time defines a series of events that may all be linked to slab break off

tectonic reconstruction of cyprus reveals late miocene continental collision of africa and anatolia abstract the extended northern continental margin of africa is currently colliding with and under thrusting northward below cyprus the age of onset of this collision is poorly constrained but is critical if we are to quantify continental subduction and evaluate its role during spectacular recent uplift of southern turkey from 7 ma to the present here we reevaluate the evolution of northern cyprus and document the modern structure of the kyrenia fold thrust belt in a balanced cross section for the first time to determine the timing and amount of shortening the belt deformed an upper cretaceous to miocene stratigraphy which was deposited onto a metamorphic basement the fold thrust belt was previously proposed to have formed during two stages in eocene and late miocene time based on stratigraphic and limited structural evidence we revaluate evidence for an eocene phase of thrusting in kyrenia and find that 1 repetitions of eocene and older rocks are explained by miocene thrusting and newly documented olistoliths were misinterpreted as pre miocene thrust slices 2 uplift in eocene time was not isolated to kyrenia but also affected northern arabia and results from regional dynamic topography or forebulge formation based on kinematic constraints from a plate reconstruction we interpret that metamorphic rocks in kyrenia were metamorphosed by cretaceous burial below the troodos ophiolite and were subsequently exhumed by upper plate extension during latest cretaceous obduction onto the african margin the latest cretaceous miocene plate boundary between africa and the taurides was located to the north of kyrenia the kyrenia fold thrust belt accommodated a minimum of 17 5 km of shortening as a result of 9 6 ma thrusting as a result of initial africa taurides collision the northern edge of african continental crust arrived below the taurides where it has been seismologically imaged in late pleistocene time and may have caused or contributed to recently recognised major tauride uplift since 0 5 ma

the african plate a history of oceanic crust accretion and subduction since the jurassic we present a model for the jurassic to present evolution of plate boundaries and oceanic crust of the african plate based on updated interpretation of magnetic gravity and other geological and geophysical data sets location of continent ocean boundaries and age and geometry of old oceanic crust jurassic and cretaceous are updated in the light of new data and models of passive margin formation a new set of oceanic palaeo age grid models constitutes the basis for estimating the dynamics of oceanic crust through time and can be used as input for quantifying the plate boundary forces that contributed to the african plate palaeo stresses and may have influenced the evolution of intracontinental sedimentary basins as a case study we compute a simple model of palaeo stress for the late cretaceous time in order to assess how ridge push slab pull and horizontal mantle drag might have influenced the continental african plate we note that the changes in length of various plate boundaries especially trenches do not correlate well with absolute plate motion but variations in the mean oceanic crust age seem to be reflected in acceleration or deceleration of the mean absolute plate velocity

uranium lead isotopic ages of plagiogranites from the troodos ophiolite cyprus and their tectonic significance zircon populations from two plagiogranites in the plutonic section of the troodos ophiolite yield u pb dates between 90 3 0 7 and 92 4 0 7 ma zircons from one of the two samples yield u pb dates of 90 3 0 7 and 92 1 0 7 ma this difference is greater than our analytical error and the zircons are therefore considered to be slightly discordant two fractions from another sample are internally and externally concordant and have an average date of 91 6 1 4 ma this date is adopted as the age of plagiogranite crystallization the plutonic section of the troodos ophiolite is complex in that several generations of intrusion can be identified the plagiogranites occur at the top of the intrusive section and represent fractionated residua of magma chambers related to the lower pillow lavas they are possibly slightly older than small ultramafic layered complexes that represent the final intrusive episode within the troodos ophiolite there is good agreement between our results and the ages of radiolaria which occur in umbers intercalated with the upper pillow lavas of troodos blome and irwin 1985 this shows that the 75 to 85 ma k ar dates on the lavas and sheeted dikes desmet et al 1978 delaloye and desmet 1979 delaloye et al 1980 staudigel et al 1986 represent age resetting unrelated to ophiolite formation the troodos u pb zircon ages are slightly lower than u pb zircon ages from the samail ophiolite in oman which vary between 93 5 and 97 9 ma and average 95 ma tilton et al 1981 the small difference in age between the troodos and the samail ophiolites and the geochemical similarities of basalts from both complexes to island arc volcanic rocks imply that a 3000 km axis of rift related island arcs formed between 91 and 98 ma emplacement of the ophiolites followed during the early maastrichtian

palaeomagnetic insights into the evolution of neotethyan oceanic crust in the eastern mediterranean abstract a synopsis of palaeomagnetic data from three late cretaceous eastern mediter ranean tethyan ophiolites troodos hatay and baer bassit and their sedimentary coversequences is presented these data provide valuable insights into the role of regional andlocal scale tectonic rotations in the geodynamic evolution of neotethyan oceanic crust thegeologically earliest phases of tectonic rotation are documented in the troodos ophiolite where rotations around both subvertical and subhorizontal axes are readily related to thedevelopment of the spreading fabrics and structures during crustal genesis subsequent c 74 anticlockwise intra oceanic rotation of a troodos microplate has been quantified throughanalysis of the in situ sedimentary cover of the troodos ophiolite results indicate that bulkanticlockwise rotation began soon after the cessation of spreading and ended by the end ofthe eocene with c 50 60 of microplate rotation being over by the maastrichtian the timeat which ophiolite thrust sheets were emplaced onto the arabian continental margin to theeast of troodos recent results from the emplaced structurally dismembered baer bassitophiolite indicate extreme anticlockwise rotations of ophiolitic thrust sheets varying on akilometre scale new data from the post emplacement sedimentary cover confirm that onlya small component of these rotations is due to post emplacement tectonism baer bassitrepresents the leading edge of the emplaced ophiolitic sheet new data from the morecoherent section preserved in the hatay ophiolite to the north demonstrate significantanticlockwise rotation this is equivalent to the rotation of the most northerly part of thebaer bassit units to the south and is of the same sense and magnitude as the pre maastrichtian phase of microplate rotation documented in the troodos this suggests acommon intra oceanic origin for the majority of the troodos and hatay rotations and asignificant component of the more variable rotations observed in baer bassit overall therefore the data support a model involving 1 intra oceanic rotation of a coherent regionof crust within the southern neotethyan basin this rotated unit is more areally extensivethan has previously been inferred from consideration of data from the troodos ophiolitealone 2 emplacement of part of the rotated unit onto the arabian platform 3 subsequentlocalized post emplacement modification related to the development of the current plateconfiguration

precise 40ar 39ar ages from the metamorphic sole rocks of the tauride belt ophiolites southern turkey implications for the rapid cooling history the tauride belt ophiolites in southern turkey are located on both sides of the e w trending mesozoic tauride carbonate platform they comprise the lycian antalya beysehir mersin alihoca and pozanti karsanti ophiolites from west to east each ophiolite has a metamorphic rock unit either at the base of the peridotites or in the melange units the metamorphic sole rocks generally consist of amphibolite at the top and near the contact with the overlying tectonized harzburgite of the ophiolites and mica schists mostly at the base near the tectonic contact with the underlying ophiolitic melange 40 ar 39 ar measurements from the metamorphic sole rocks of the lycian antalya and beysehir ophiolites are the first precise ages dating intra oceanic thrusting and the cooling age history during the closure of the neotethyan ocean amphiboles and white micas from the metamorphic sole rocks of the ophiolites yielded 40 ar 39 ar ages between 90 7 0 5 ma and 93 8 1 7 ma and between 91 2 2 3 ma and 93 6 0 8 ma respectively hornblende plateau ages from the amphibolites of the lycian ophiolites near koyce iz agree with those of antalya indicating that they were metamorphosed simultaneously in the neotethyan ocean the white micas display plateau ages concordant with the amphiboles from the same units in koyce iz and yesilova lycian ophiolites and from the pozanti karsanti ophiolite suggesting that the metamorphic sole rocks were rapidly cooled after their generation

crustal accretion and tectonic setting of the troodos ophiolite cyprus abstract the troodos ophiolite is composed of two distinct magmatic suites an early relatively high tio 2 basaltic suite constitutes the upper gabbros the sheeted dike complex and the andesitic to rhyodacitic lower pillow lavas a late low tio 2 basaltic andesite suite constitutes the lower ultramafic to gabbroic cumulates and the upper pillow lavas parental magmas to the early suite originated as partial melts from hydrous relatively undepleted peridotite diapirs rising in a mantle wedge in response to dehydration of a subducting crust the late basaltic andesite suite is highly depleted in incompatible elements and show similarities with second stage or refractory basalts from oceanic spreading centers the troodos basaltic andesites and associated cumulates may thus have formed in response to continued adiabatic upwelling as second stage melts from the hydrous water undersaturated peridotite diapirs from which the earlier spreading related magmas were extracted the basaltic andesites formed in a relatively slow spreading or non spreading tectonic environment and dominantly crystallized in magma chambers underplating the troodos ophiolite the extrusion of the basaltic andesites of the upper pillow lavas occurred simultaneously with still active evolving volcanic centers belonging to the earlier magmatic suite an alternative possibility would be that the basaltic andesites separated from renewed diapirs rising as a consequence of re initiation of subduction and liberation of fluids from the subducting slab into the overlying depleted peridotite the existence of lree and lil enriched lavas among the upper pillow lavas support this possibility the apparent conflict between a spreading related geology and the arc petrology and geochemistry of the troodos ophiolite may be an artifact of lack of detailed studies of the geology and chemistry of oceanic and back arc rifting environments however it is proposed that the available data for the troodos ophiolite are consistent with its formation in a short lived spreading basin formed by splitting of an immature submarine arc

coal and coal macerals as source rocks for oil and gas abstract the role of coals in the generation and migration of hydrocarbons is discussed from the viewpoints of chemistry and petrology extract data and considerations of volatile matter and maturity suggests that under geochemical conditions most coals can give rise to oil as well as gas a distinction is drawn between release of absorbed oil and formation of hydrocarbons by thermal breakdown of the coal matrix itself the generation and preservation of oil require not only that suitable lipidic structures be present but that the product oil can escape before being cracked to gas exinite preferably in large discrete particles is the most oil prone maceral vitrinite can form oil but subsequent migration depends on the availability of cracks and fissures in the coal matrix the most highly reflecting forms of inertinite e g fusinite have no inherent capacity to generate oil low reflectance inertinite such as is common in many australian coals may have minor source potential a speculative attempt is made to quantify the oil generating capacity of coal macerals and mixtures as a general broad rule on a weight basis exinite can produce ten times more oil than vitrinite and a hundred times more than inertinite approximate calculations suggest that thermal maturation of coals can account for all the known oil and gas reserves in the gippsland and cooper basins of australia even if only 1 of generated hydrocarbons is trapped

the oligocene recent evolution of the mesaoria basin cyprus and its western marine extension eastern mediterranean abstract the neogene stratigraphic and structural evolution of the mesaoria basin and kyrenia range is studied using multi channel seismic reflection profiles from their western marine extension the region north of the front of the troodos larnaka culmination constitutes a crustal scale s verging thick skinned linked imbricate thrust system comprising most of the forearc region north of the present day cyprus arc in the eocene thrust activity gave rise to the prominent growth of the troodos larnaka culmination and concurrent imbrication further north in the forearc region creating the root of the kyrenia fold thrust belt northward retreat of the active thrust front in the oligocene miocene led to the development of a foredeep across the root of the kyrenia fold thrust belt with a prominent depositional foredeep ramp situated at the current front of this belt crustal contraction continued in the miocene along the front of the troodos larnaka culmination leading to the progressive shoaling of the basin carried on the backlimb of this culmination in the late miocene thrust activity became widespread in the forearc region with structural contraction being focussed on the kyrenia fold thrust belt pliocene thrust activity in the forearc region is primarily focussed on the kyrenia fold thrust belt with much uplift occurring in the mid late pliocene but continuing to the present the mesaoria basin evolved in the miocene to pliocene as a piggy back basin our data negate earlier models that postulate a phase of crustal extension in the forearc region during the oligocene to mid late pliocene

source to sink the development of the latest messinian to pliocene quaternary cilicia and adana basins and their linkages with the onland mut basin eastern mediterranean abstract multi channel seismic reflection profiles show that there is a thick northeast southwest elongated lobe of uppermost messinian and pliocene quaternary sediments across the cilicia basin extending into the onland adana basin three prominent seismic markers divide this succession into three subunits detailed isopach maps constructed using a dense grid of depth converted seismic reflection profiles show that these three subunits display distinctive sediment distribution patterns that can be confidently related to eastward deposition from the goksu river to the west subsidence rates calculated at 95 locations within the cilicia and adana basins using osxbackstrip show that the central axis of the cilicia adana basin complex is subsiding at a rate of 10 20 mm per year the subsidence rates sharply decrease both toward the misis kyrenia fault zone in the south and east and the turkish continental margin in the west and north to values of 0 10 0 15 mm per year subsidence rates were 0 10 0 20 mm per year during the deposition of the middle and upper pliocene but decreased to 0 05 mm per year sedimentation rates calculated for the three subunits compared to the present day rate of sedimentation by the goksu river clearly show that sedimentation in the early pliocene interval was significantly greater than it is today the data show that the dramatic subsidence of the cilicia basin 2000 m since the messinian occurred in synchroneity with the rise of the mut basin nestled over the central taurus mountains the adjacency of the mut and cilicia basins suggests that there must be a common local cause for the uplift of the mut basin and the subsidence of the cilicia basin we believe that the rise of the central taurus mountains represents an additional load on the underlying asthenosphere the isostatic response of which would have caused the subsidence in the cilicia basin

tectonic history of the hatay ophiolites south turkey and their relation with the dead sea rift abstract the kizildag ophiolite massif lies in the hatay region of s turkey some structural relationships in the area are examined and two geological sections through the ophiolite are presented a sequence of structural events dealing with the emplacement and post emplacement history is established the significance of the events is discussed and it is suggested that the post emplacement structural history was dominated by movements along the dead sea rift

the structure of the africa anatolia plate boundary in the eastern mediterranean new marine deep seismic reflection data from south of cyprus to the syrian coast provide images of the upper crustal structure of the cyprean arc indicating that the deformation is partitioned along strike slip fault systems distributed over a wide zone rather than forming a sharp plate boundary between african and anatolian plates three major submarine strike slip fault systems tens of kilometers in length are mapped which follow bathymetric features and merge together toward the east these structures exhibit the three dimensional characteristics typical of strike slip deformation zones throughout the seven pre stack depth migrated sections including several sets of positive flower structures forming bathymetric ridges and the intervening contemporaneous subbasins beneath the plio quaternary sediments 500 m thick that are blanketing the whole area and that reflect only the main surface traces of the fault systems the subbasins are of varied dimensions and have rapid lateral changes in the thickness of the sedimentary fill they include two major unconformities that have been correlated throughout the data marked by the m and k reflections the m reflection is well imaged above varied thickness of messinian evaporites and the k reflection commonly appears at the base of syntectonic tertiary age sediments within the eastern cyprean arc the k reflection corresponds to the basement cover contact indicating that the strike slip tectonic scenario may have been active since the uppermost cretaceous or lowermost paleogene times to present the active deformation front of the alpine belt in the eastern mediterranean corresponds to a strike slip fault system that forms a 110 arc and coincides at the southern slope of the hecateaus rise continuing along the latakia ridge to the syrian coast the mapped structures fit within a general kinematic framework of left lateral transcurrent deformation that transfers slip from the subduction zone southwest of cyprus into the dead sea transform system in the east this change in the mode of deformation at the africa anatolia plate boundary occurs toward the junction between african anatolian and arabian plates

alakir cay group antalya complex sw turkey a deformed mesozoic carbonate margin abstract the alakir cay group comprises complexly deformed mesozoic sedimentary rocks originally deposited along a passive carbonate margin the sediments now form a tectonically imbricated stack of thrust sheets kumluca zone emplaced westwards over a relatively autochthonous carbonate platform bey daglari zone the kumluca zone is bounded tectonically to the east by mafic and ultramafic rocks with related sediments godene zone representing oceanic crust produced during early stages of continental separation and originally forming the more distal part of the margin detailed mapping and structural analysis allow the thrust sheets to be pulled back to reconstruct a stretch of the carbonate margin about 10 km wide by 25 km long within the thrust sheets fragmentary basal sequences of quartzose sandstones hatip formation derived from the north were laid down during late triassic continental rifting subsequent late triassic halobia and radiolarian bearing calcilutites bozyer foramtion are comparable with peri platform deep water oozes found for example in the bahamas an end triassic hiatus involved substantial down margin sediment redeposition jurassic to early cretaceous sediments include both non calcareous and calcareous silts laid down together with radiolarites in deep water below the carbonate compensation depth karabuk formation an upward transition to cretaceous planktonic foraminiferal chalks is seen in some more proximal sequences tectonic disruption of the margin began in latest cretaceous time and ended with westward thrusting over the carbonate platform in the miocene small scale facies variation of the margin is illustrated by unstretching the thrust sheets and correlation of 33 measured logs particularly the sediments become more distal across the margin away from the carbonate platform along margin variation is especially evident in the thickness and composition of redeposited carbonates in the late triassic hemipelagic rocks comparison with other carbonate margin sequences in the antalya complex and elsewher implies that the alakir cay sediments represent deep water outer margin facies which lapped over adjacent oceanic crust more proximal redeposited carbonates are not seen perhaps due to overthrusting

evidence from the kyrenia range cyprus of the northerly active margin of the southern neotethys during late cretaceous early cenozoic time sedimentary geology and planktonic foraminiferal biostratigraphy have shed light on the geological development of the northern active continental margin of the southern neotethys in the kyrenia range following regional triassic rifting a carbonate platform developed during jurassic cretaceous time followed by its regional burial deformation and greenschist facies metamorphism the platform was exhumed by late maastrichtian time and unconformably overlain by locally derived carbonate breccias passing upwards into upper maastrichtian pelagic carbonates in places the pelagic carbonates are interbedded with sandstone turbidites derived from mixed continental basic volcanic neritic carbonate and pelagic lithologies in addition two contrasting volcanogenic sequences are exposed in the western central kyrenia range separated by a low angle tectonic contact the first is a thickening upward sequence of campanian lower maastrichtian pelagic carbonates silicic tuffs silicic lava debris flows and thick bedded to massive rhyolitic lava flows the second sequence comprises two intervals of basaltic extrusive rocks interbedded with pelagic carbonates the basaltic rocks unconformably overlie the metamorphosed carbonate platform whereas no base to the silicic volcanic rocks is exposed additional basaltic lavas are exposed throughout the kyrenia range where they are dated as late maastrichtian and late paleocene middle eocene in age in our proposed tectonic model related to northward subduction of the southern neotethys the kyrenia platform was thrust beneath a larger tauride microcontinental unit to the north and then was rapidly exhumed prior to late maastrichtian time pelagic carbonates and sandstone turbidites of mixed largely continental provenance then accumulated along a deeply submerged continental borderland during late maastrichtian time the silicic and basaltic volcanogenic rocks erupted in adjacent areas and were later tectonically juxtaposed the campanian early maastrichtian silicic volcanism reflects continental margin type arc magmatism in contrast the upper maastrichtian and paleocene middle eocene basaltic volcanic rocks erupted in an extensional or transtensional setting likely to relate to the anticlockwise rotation of the troodos microplate

gps constraints on continental deformation in the africa arabia eurasia continental collision zone and implications for the dynamics of plate interactions 1 the gps derived velocity field 1988 2005 for the zone of interaction of the arabian african nubian somalian and eurasian plates indicates counterclockwise rotation of a broad area of the earth s surface including the arabian plate adjacent parts of the zagros and central iran turkey and the aegean peloponnesus relative to eurasia at rates in the range of 20 30 mm yr this relatively rapid motion occurs within the framework of the slow moving 5 mm yr relative motions eurasian nubian and somalian plates the circulatory pattern of motion increases in rate toward the hellenic trench system we develop an elastic block model to constrain present day plate motions relative euler vectors regional deformation within the interplate zone and slip rates for major faults substantial areas of continental lithosphere within the region of plate interaction show coherent motion with internal deformations below 1 2 mm yr including central and eastern anatolia turkey the southwestern aegean peloponnesus the lesser caucasus and central iran geodetic slip rates for major block bounding structures are mostly comparable to geologic rates estimated for the most recent geological period 3 5 myr we find that the convergence of arabia with eurasia is accommodated in large part by lateral transport within the interior part of the collision zone and lithospheric shortening along the caucasus and zagros mountain belts around the periphery of the collision zone in addition we find that the principal boundary between the westerly moving anatolian plate and arabia east anatolian fault is presently characterized by pure left lateral strike slip with no fault normal convergence this implies that extrusion is not presently inducing westward motion of anatolia on the basis of the observed kinematics we hypothesize that deformation in the africa arabia eurasia collision zone is driven in large part by rollback of the subducting african lithosphere beneath the hellenic and cyprus trenches aided by slab pull on the southeastern side of the subducting arabian plate along the makran subduction zone we further suggest that the separation of arabia from africa is a response to plate motions induced by active subduction

the neogene evolution of the outer latakia basin and its extension into the eastern mesaoria basin cyprus eastern mediterranean the neogene stratigraphic and structural evolution of the eastern mesaoria basin is studied using multi channel seismic reflection profiles from the eastern marine extension of the basin into the outer latakia basin the region includes three major tectonic elements troodos larnaka culmination kyrenia fold thrust belt and the intervening mesaoria and outer latakia basins the troodos larnaka culmination is a large ophiolite cored ramp anticline developed above a deep seated s verging thrust complemented by a footwall imbricate thrust fan system extending into the cyprus basin the outer latakia basin is a large piggy back basin carried on the northern flank of the troodos larnaka culmination the kyrenia fold thrust belt is developed as a s verging trailing imbricate fan system these three tectonic elements form part of a crustal scale s directed linked thrust system which has a protracted tectonic history with major pulses of contraction in the eo oligocene the late miocene and the middle plio quaternary this system extends southward well into the cyprus basin and probably links with the subduction zone between the african plate and the anatolian microplate patterns of thrust activity in this linked thrust system exclude models of s migration of the plate boundary from mid tertiary to recent instead the upper plate is viewed as a broad zone of diffuse convergence distributed across a number of active fold thrust zones