aftsolve a program for multi kinetic modeling of apatite fission track data aftsolve is a computer program for deriving thermal history information from apatite fission track data it implements a new fission track annealing model that takes into account the known kinetic variability among different apatite species to fully utilize this model a fission track worker must obtain data that can be used to infer the kinetic characteristics of each apatite grain from which a measurement was taken such data can consist of etch figure lengths or chemical composition the benefit of this overall approach is that it allows useful information to be derived from previously unusable analyses extends the practical range of geological temperatures constrained by fission track analyses and increases overall confidence in model predictions aftsolve also incorporates the effects of fission track orientation relative to the apatite crystallographic c axis variation in initial track length and the biasing effect of 2 5 2 cf irradiation for enhancing confined horizontal track length detection aftsolve is written for windows operating systems and has a graphical interface that allows interactive input of thermal histories and real time generation of estimates for fission track length distributions and ages for up to six simultaneously modeled kinetic populations it also includes procedures for estimating the range of time temperature histories that are statistically consistent with a data set and constraints entered by the user

plio quaternary kinematic development and paleostress pattern of the edremit basin western turkey abstract the edremit basin and kazdag high are the most prominent morphological features of the biga peninsula in northwest anatolia there is still no consensus on the formation of edremit basin and debates are on whether the basin evolved through a normal a right lateral or a left lateral strike slip faulting in this study the geometric structural and kinematic characteristics of the edremit basin are investigated to make an analytical approach to this problem the structural and kinematic features of the faults in the region are described according to field observations these fault slip data derived from the fault planes were analyzed to determine the paleostress pattern of faulting in the region according to the performed analysis the southern end of the biga peninsula is under the influence of the ene wsw trending faults of the region such as the yenice gonen the edremit the pazarkoy and the havran balikesir fault zones the right step over geometry and related extension caused to the development of the edremit basin as a transtensional pull apart basin between the havran balikesir fault zone and the edremit fault zone field observations showed that the plio quaternary faults at the edremit gulf and adjacent areas are prominently right lateral strike slip faults our paleostress analyses suggest a dominant ne sw extension in the study area as well as nw se direction this pattern indicates the major effects of the north anatolian fault system and the component of aegean extensional system in the region however our kinematic analysis represents the dominant signature of the north anatolian fault system in basin bounding faults the field observations and kinematic findings of this study are also consistent with the regional gps paleomagnetic and seismological data this study concludes that the north anatolian fault system is the prominent structure in the current morphotectonic framework of the edremit gulf and adjacent areas

petrochemical features of miocene volcanism around the cubukludag graben and karaburun peninsula western turkey implications for crustal melting related silicic volcanism abstract widespread neogene volcanism mainly intermediate and rarely mafic and felsic in composition was controlled by the extensional tectonic regime in western turkey the karaburun and cumaovasi volcanics are the cases for understanding the magma source s and petrological processes producing the extension related mafic and felsic volcanism the karaburun volcanics kv are mainly oriented north to south in the karaburun peninsula and span a wide spectrum from basalt 20 ma to rhyolite 16 ma and younger trachyte and trachydacites 13 ma the products of the subaerial silicic volcanism the cumaovasi volcanics cv 17 ma which are represented by cluster of rhyolite domes related pyroclastics occur within the ne sw trending cubukludag graben and intermediate and mafic volcanic rocks are lack in this area the lavas of the cumaovasi volcanics are high silica rhyolites and rare dacites which are calc alkaline peralumious and enriched significantly in lile extremely low sr ba values extremely eu depletions and very low la n yb n ratios are typical for the rhyolites of cv similar to the topaz rhyolites the karaburun volcanics with the exception of the minor alkaline basaltic and trachytic lavas are mainly calc alkaline and metaluminous intermediate lavas 87 sr 86 sr ratios of the kv and dacitic samples of cv are close to each other and range from 0 708 to 0 709 while sr isotopic ratios of the rhyolites are significantly high and variable 0 724 0 786 143 nd 144 nd ratios of the cv and kv except for the alkaline samples are similar for both sequences vary from 0 51230 to 0 51242 geological geochemical isotopic and radiochronologic data reveal that the kv and cv were formed in extensional tectonic setting but evolved by different petrological processes in different magma chambers during the neogene underplated mafic magma was injected into the crust and hybridized by mantle and crustal derived materials geochemical features and trace element modeling for the mafic members of the kv indicate that they were derived from enriched lithospheric mantle and modified by fractional crystallization from basalt to rhyolite helvaci et al 2009 unexpectedly the felsic lavas from cumaovasi region have a unique chemical composition and similar to the extension related rhyolites formed from small magma bodies our data reveal that extension related mafic inputs caused crustal anatectic melting and formed felsic melts that rapidly ascended into the upper crust the cumaovasi felsic rocks were differentiated into the highly evolved silica rich melts within the magma chambers trapped near the surface

timing kinematics and cause of aegean extension a scenario based on a comparison with simple analogue experiments abstract since the early 1970s most geodynamic models proposed for the eastern mediterranean consider that the initiation of extension in the aegean during the late middle miocene or later was a direct consequence of the westward extrusion of anatolia away from the arabia eurasia collision front in the late 1990s a few models have taken into account the increasing evidence for an earlier initiation of aegean extension arising mostly from the analysis of deformation within the various alpine metamorphic complexes of the area based largely on our own investigations we first present a review of the data that reliably constrain the minimum age for the initiation of extension in these complexes it shows that regional scale extension with a pattern of stretching orientations similar to that of the pliocene pleistocene was already strongly active in the aegean before the onset of arabian indentation into eurasia lower miocene vs middle or upper miocene this implies that the initiation of aegean extension did not result from the lateral extrusion of anatolia instead extension may have started owing to a process of gravity spreading of the continental lithosphere that had previously been thickened during alpine collision the main arguments favouring this interpretation are presented and a preliminary scenario is proposed for the neogene evolution of the eastern mediterranean in which lateral extrusion of anatolia occurred lately during southward spreading of the aegean lithosphere in order to test this hypothesis further physical experiments simulating the horizontal spreading of a continental lithosphere toward a free boundary have been carried out the analysis of various elements of the deformation field displacements strain rotations fault pattern and kinematics both in the experiments and in the aegean domain reveals an excellent agreement between the two not only do early stages of aegean extension appear to fit the gravity spreading hypothesis but so does the recent to present internal deformation of the aegean transverse e w active shortening observed in the northern aegean is commonly taken as one of the most striking pieces of evidence that aegean extension results from the lateral extrusion of anatolia the experiments indicate that such transverse shortening may equally develop as a result of pure gravity spreading associated with a pattern of faults and rotations that compares well with that of the northern aegean pure dextral shearing along some strands of the north aegean trough fault system and the related development of an asymmetric pattern of faults in the northern aegean are eventually the only features that evidently arise from the extrusion of anatolia since less than 3 ma finally we argue that during the early stages of aegean extension since at least 21 ma and until ca 11 ma the distribution of extensional strain on a regional scale has been controlled by the distribution of earlier thickening post thickening thermal weakening through partial melting of deep levels of the crust probably accounts for the localization of extensional strain within the areas of thick crust restoring the aegean in its most likely configuration at the onset of bulk crustal extension suggests that 1 the extensional strain rate remained roughly constant or has eventually decreased since the onset of aegean extension and 2 the amounts of extension before and after 16 ma have been roughly equal

kinematic reconstructions and magmatic evolution illuminating crustal and mantle dynamics of the eastern mediterranean region since the late cretaceous the relationship between subduction dynamics and crustal deformation in the mediterranean region has been recently studied using three dimensional 3d numerical models such models require however a detailed information concerning the past geological evolution we use stratigraphic petrologic metamorphic structural paleomagnetic and magmatic data to build new kinematic reconstructions of the eastern mediterranean region since the late cretaceous using the principle of non rigid domains the motions of the 56 deforming domains defined in this work are calculated based on published paleomagnetic rotations the directions and amounts of displacement on crustal scale shear zones and the burial and exhumation histories of the main metamorphic units extracted from these reconstructions paleotectonic maps and lithospheric scale cross sections illustrate that the present day subduction zone has been continuously retreating southward since the late cretaceous and has accreted several small continental domains in the process we find evidence for two back arc related extensional events 1 slow extension along the balkans and the pontides in the late cretaceous while the trench was long and linear and 2 faster extension in the rhodope aegean west anatolian region since the eocene oligocene rapid rotation of the hellenides between 15 and 8 ma probably indicates a slab tearing event below western anatolia that could have further accelerated this extensional kinematics spatial distribution and the geochemical signature of magmatic centers integrated in these reconstructions allow us to trace mantle related processes revealing the deep dynamics that controls both the magma genesis and the crustal deformation

discriminating between tectonic and sedimentary burial in a foredeep succession northern apennines an extensive apatite fission track survey has been carried out on the marnoso arenacea foredeep succession in the northern apennines the data show a general decrease of the maximum paleotemperature undergone by the sediments toward the foreland areas the maximum burial calculated by using a geothermal gradient of 20 c km 1 spans from more than 5 km to less than 2 5 km and indicates that the previously assessed total thickness of the marnoso arenacea succession is not enough to justify the determined values it is concluded that a now eroded ligurian wedge up to 5 km thick was present on top of the marnoso arenacea sediments

miocene nne directed extensional unroofing in the menderes massif southwestern turkey structural investigations in the central part of the menderes massif odemio kiraz submas sif reveal the presence of a large scale low angle extensional shear zone with a top to the n ne shear sense regional ductile deformation was accompanied by the intrusion of two syntectonic granodiorites that have been dated with the 40 ar 39 ar method one hornblende isochron age of 19 5 1 4 ma and two biotite plateau ages of 13 1 0 2 and 12 2 0 4 ma respectively constrain that extension was already active in the early miocene successive tectonic denudation of the odemio kiraz submassif resulted in the formation of a n dipping detachment fault in which ductile fabrics were severely reworked by cataclasis under decreasing temperature syntectonic neogene sediments currently exposed along the southern margin of the gediz graben were deposited in the hanging wall of the extensional fault system and were tectonically emplaced onto the cataclasites during progressive exhumation minor rotation c 15 caused southward tilting of the sediments ongoing nne directed extension created a steep normal fault that truncates the detachment fault and constitutes the southern boundary fault of the gediz graben

tectonic evolution of the gediz graben field evidence for an episodic two stage extension in western turkey western turkey is one of the most spectacular regions of widespread active continental extension in the world the most prominent structures of this region are e w trending grabens e g gediz and buyuk menderes grabens and intervening horsts exposing the menderes massif this paper documents the result of a recent field campaign field geological mapping and structural analysis along the southern margin of the modern gediz graben of pliocene 5 ma age this work provides field evidence that the presently low angle ductile brittle detachment fault is cut and displaced by the high angle graben bounding normal faults with total displacement exceeding 2 0 km the evolution of the n s extension along the gediz graben occurred during two episodes each characterized by a distinct structural styles 1 rapid exhumation of menderes massif in the footwall of low angle normal fault core complex mode during the miocene 2 late stretching of crust producing e w grabens along high angle normal faults rift mode during pliocene quaternary times separated by a short time gap the later phase is characterized by the deposition of now nearly horizontal sediments of pliocene age in the hanging walls of the high angle normal faults and present day graben floor sediments the evolution of extension is at variance with orogenic collapse and or back arc extension followed by the combined effect of tectonic escape and subduction rollback processes along the aegean cyprean subduction zone consequently it is misleading to describe the miocene sediments exhumed on shoulders of the gediz graben as simple graben fill

exhumation and doming of the thasos metamorphic core complex s rhodope greece structural and geochronological constraints abstract the thasos island metamorphic core complex s rhodope n aegean sea was generated between 26 and 13 ma progressive extensional tectonics was associated with upwarping of the deeper parts of this core complex to a narrow gneiss dome and with formation of a steep topographic high we present a combined structural microstructural and geochronological study that constrains the deformation time path of progressive extension and exhumation thasos island consists of three superimposed more or less flat lying metamorphic units with downward decreasing geochronologic ages which are separated by two systems of low angle normal detachment surfaces trending nw se the upper unit stayed in supracrustal level since 50 ma representing the upper plate during an early phase of extension not later than 26 23 ma upper levels of the core complex intermediate unit underwent pervasive mylonitization with top to the sw shear from about 21 ma onward the intermediate unit was rigid and top to the sw slip continued at least until 13 8 ma on the discrete detachment surface that separates the core complex from the upper plate yet in the 21 15 ma period deeper levels lower unit still deformed plastically and deformation successively concentrated in zones of high strain and in discrete detachment surfaces that caused decoupling of the lower from the intermediate unit these indicate downdip movements in opposite sense associated with doming of the lower unit at that stage simultaneously the intermediate unit was fragmented on high angle normal faults that sole into the dome bounding detachment surface and roof into the core complex bounding detachment surface these faults confine tilt blocks that are arranged around the lower unit gneiss dome doming of the core complex occurred simultaneously with subsidence of basins located on the upper plate

constraints on the kinematics of post orogenic extension imposed by stretching lineations in the aegean region abstract new kinematic data from shear zones of tertiary age in the metamorphosed basement of the aegean region in combination with published kinematic lithological and palaeomagnetic data have enabled us to determine a detailed kinematic evolution of the region during post orogenic extension in the aegean three distinct stages are recognised firstly extension of both the western and eastern aegean started in the late oligocene early miocene 36 25 ma ago initially in an 023 direction stage two started shortly after this with the division of the aegean crust into the west aegean block a coupled assemblage of small blocks bound on its northwestern and southeastern margins by the scutari pec line and mid cycladic lineament fracture zones respectively between 25 ma and 3 ma the west aegean block underwent 30 clockwise rotation whilst the eastern aegean underwent on average 19 anticlockwise rotation rotation of the west aegean block as a semi coherent block was aided by the relative coolness of the block compared to the warmer eastern aegean region as the crust thinned and rotated the nw se trending faults which characterise the west aegean block were cross cut by e w trending faults in the latest miocene pliocene the thermal front migrated westwards into the west aegean block and the mid cycladic lineament ceased activity the final kinematic stage marked the start of the subdivision of the west aegean block into two portions in the pliocene the southeastern portion nw cycladic area coupled with the sw cycladic area to form a central aegean block that started to translate southwest the northern and western portion rotated a further 10 15 clockwise whilst the southeastern rim rotated anticlockwise these data demonstrate that aegean post orogenic extension is not dominated by a single block rotation or radial spreading event but is characterised by the sequential formation and reformation of lithospheric scale blocks that have developed in response to large scale partitioning of rotational strain

structure and kinematics of upper cenozoic extensional detachment on naxos and paros cyclades islands greece this paper presents a study of the ductile and brittle deformation on naxos and paros islands cyclades greece previous maps and studies of the two islands have shown that a major low angle fault zone separates surface rocks above the contact from an initially deep seated unit below showing a metamorphic evolution from high to low pressures structural analysis as well as available stratigraphical metamorphic and geochronological data taken together demonstrate that this fault zone is a major normal sense detachment zone dipping to the north rapid denudation of footwall rocks subsequent to high temperature metamorphism at an estimated rate of 1 8 9 5 mm yr attests for tectonic unroofing during regional scale top to the north ductile shearing the change from ductile to brittle behavior of the footwall rocks together with a progressive localization of high strain intensity deformations just below the hangingwall is explained by the progressive cooling of the uprisen footwall of the detachment mio pliocene clastic sediments in the hangingwall represent the infilling of half grabens opened in between major normal faults that are synthetic to the underlying ductile shear zone these sediments are as old as aquitanian 25 ma or younger than the earliest recognized evidence of ductile extension in the footwall this provides a minimum age for the onset of extension in the cyclades which appears significantly older than maximum ages reported up to now 13 5 ma structural data strongly suggest that the detachment fault was initially rather low dipping 35 an evolutionary model is proposed in which migmatite domes in the footwall correspond to the uprise of the lower ductile crust between two separating upper crustal blocks during a process of asymmetric boudinage of the crust this detachment model applies to a previously thickened continental lithosphere which then suffers thermal relaxation and weakening allowing extensional deformation to reach a climax during and subsequent to high temperature metamorphism in the cyclades crustal scale extension started after early cenozoic thrusting while the crust was still thick or less likely before late underthrusting below the present surface

u pb and 40ar 39ar geochronology of the symvolon granodiorite implications for the thermal and structural evolution of the rhodope metamorphic core complex northeastern greece north aegean continental lithosphere was thickened by southwest vergent thrusting and continental subduction within the alpine collisional orogen but has subsequently been greatly extended on a northeast southwest axis in the back arc of the hellenic subduction zone crosscutting relationships with two granodiorite bodies emplaced at 31 33 ma the xanthi and eastern vrondou plutons constrain a pre mid oligocene origin of alpine convergent structures in northeastern greece post alpine thinning of the north aegean nappe pile began in earliest miocene time and has been accommodated by a succession of distinct structural systems the earliest of these the symvolon shear zone appears to represent a midcrustal coaxial rupture of the falakron marble series a carbonate platform 5000 m thick that was subducted northeastward beneath high grade rocks of the rhodope metamorphic province in late alpine time zircon and titanite u pb dates and hornblende 40ar 39ar dates obtained in this study constrain the intrusion and incipient mylonitization of the symvolon or kavala granodiorite within the symvolon shear zone at 21 22 ma following its emplacement the symvolon body resided at temperatures between 300 c and 500 c for 5 7 m y during which coaxial deformation may have continued within a widening symvolon rupture the strymon valley detachment a regionally south west dipping low angle normal fault succeeded the symvolon shear zone in middle miocene time southwestward displacement of the serbo macedonian gneiss complex by as much as 80 km in the hanging wall of this detachment facilitated the unroofing of the rhodope metamorphic core complex including the falakron marble series and several tertiary plutons in its footwall biotite and k feldspar 40ar 39ar dates from 11 1 0 2 ma to 15 5 0 3 ma yielded by symvolon granodiorite samples document the cooling of the rhodope core complex below 150 c 300 c during its southwestward progressive exhumation in the footwall of the strymon valley detachment

an active bivergent rolling hinge detachment system central menderes metamorphic core complex in western turkey two symmetrically arranged detachment systems delimit the central menderes metamorphic core complex and define a bivergent continental breakaway zone in the anatolide belt of western turkey structural analysis and apatite fission track thermochronology show that a large east trending syncline within the alpine nappe stack in the central part of the orogen is related to late miocene early pliocene to recent core complex formation the syncline formed as a result of two opposite facing rolling hinges in the footwalls of each of the two detachments back rotation of the syncline limbs suggests that the detachments rotated from an initial dip of 408 608 to a currently shallow orientation of 08 208

u pb zircon geochronology of the paleogene neogene volcanism in the nw anatolia its implications for the late mesozoic cenozoic geodynamic evolution of the aegean abstract the northern aegean region was shaped by subduction obduction collision and post collisional extension processes two areas in this region the rhodope thrace biga peninsula to the west and armutlu almacik nallihan the central sakarya to the east are characterized by extensive eocene to miocene post collisional magmatic associations we suggest that comparison of the cenozoic magmatic events of these two regions may provide insights into the late mesozoic to cenozoic tectonic evolution of the aegean with this aim we present an improved cenozoic stratigraphy of the biga peninsula derived from a new comprehensive set of u pb zircon age data obtained from the eocene to miocene volcanic units in the region the compiled radiometric age data show that calc alkaline volcanic activity occurred at 43 15 ma in the biga peninsula 43 17 ma in the rhodope and thrace regions and 53 38 ma in the armutlu almacik nallihan region which are slightly overlapping we discuss the possible cause for the distinct cenozoic geodynamic evolution of the eastern and western parts of the region and propose that the rhodope thrace and biga regions in the north aegean share the same late mesozoic to cenozoic geodynamic evolution which is consistent with continuous subduction crustal accretion southwestward trench migration and accompanying extension all preceded by the late cretaceous paleocene collision along the vardar suture zone in contrast the armutlu almacik nallihan region was shaped by slab break off and related processes following the late cretaceous paleocene collision along the izmir ankara suture zone the eastern and western parts of the region are presently separated by a northeast southwest trending transfer zone that was likely originally present as a transform fault in the subducted tethys oceanic crust and demonstrates that the regional geodynamic evolution can be strongly influenced by the geographical distribution of geologic features on the subducting plate

origin and evolution of hydrothermal fluids in epithermal pb zn cu au ag deposits at koru and tesbihdere mining districts canakkale biga peninsula nw turkey abstract the koru and tesbihdere mining districts in biga peninsula northwestern turkey consist of twelve deposits covering approximately 12 km 2 the epithermal au ag enriched base metal veins and associated low grade breccia and stockwork at koru and tesbihdere are hosted by oligocene subaerial and calc alkaline volcanic rocks including basaltic andesite lavas dacitic lava tuffs rhyolitic lava domes and tuffs nw to n trending strike slip faults and e and ne trending faults constitute the most important ore controlling structures in the koru and tesbihdere districts respectively in the koru mining district galena is the dominant ore mineral in barite quartz veins containing sphalerite chalcopyrite pyrite bornite enargite and tennantite according to base metal content the tesbihdere mining district can be subdivided into sphalerite galena dominated tesbihdere mineralization and chalcopyrite pyrite dominated bakir and kuyu zones mineralization gold is present in small quantities with maximum 3 14 g t au values either as free grains in quartz or as micro inclusions in pyrite and galena the most widespread silver minerals are polybasite pearceite argentite and native silver which commonly occur as replacements of galena sphalerite and pyrite and other sulfides or as fillings of microfractures in sulfides and quartz microthermometric measurements of primary liquid rich fluid inclusions in sphalerite barite and quartz in koru indicate that the veins were formed at temperatures between 407 and 146 c from fluids with salinities between 0 7 and 12 5 wt equiv nacl barite from the tahtalikuyu kuyutasi and 5 th viraj mineralization show the highest homogenization temperatures fluid inclusion data for ore stage quartz and sphalerite from the tesbihdere mining district indicate that these minerals were deposited at temperatures between 387 and 232 c from more diluted fluids with moderate salinities between 0 2 and 10 6 wt nacl equiv tahtalikuyu and 5 th viraj mineralization show only boiling trends while kuyutasi tesbihdere bakir and kuyu zones mineralization show both boiling and isothermal mixing trends the o and h isotope compositions of ore fluids from the tahtalikuyu 18 o 1 40 to 0 25 d 72 49 to 52 68 and kuyutasi 18 o 2 29 to 3 59 d 90 70 to 70 93 mineralization indicate that there was a major contribution from a magmatic component to ore genesis based on 9 quartz samples associated with orebodies at the tesbihdere mining district the relatively higher 18 o and lower d isotope compositions from hydrothermal fluids could be attributed to a relatively dilute fluid derived by the mixing with meteoric water the pb isotope compositions also reveal that most of the lead in both mining districts is derived from the oligocene miocene magmatic rocks possibly with smaller contributions from the eocene magmatic rocks

detrital supply from subduction accretion complexes to the eocene oligocene post collisional southern thrace basin nw turkey and ne greece abstract the thrace basin is a large mostly eocene oligocene post collisional sedimentary basin which developed following the closure of the vardar izmir ankara oceanic domain latest cretaceous paleocene sandstone petrologic data framework and heavy mineral analyses and the synthesis of preexisting and new sedimentological observations along representative stratigraphic sections show that the basin fill of the southern thrace basin was mostly derived from the izmir ankara and biga intra pontide subduction accretion complexes to the south proximal facies consistently show northward paleocurrents whereas most paleocurrent indicators measured downcurrent point to an eastward paleoflow likely the result of the deflection of primary gravity flows originated along the southern margin of the basin detrital contributions from the rhodopian basement complex to the west are virtually absent within the southern thrace basin fill conversely rhodopes derived eocene proximal facies in northeastern greece are characterized by a series of coarse grained fan deltas prograding eastward and likely feeding the basin plain turbidites of the depocentral portion of the thrace basin now concealed in the subsurface to the north of our study area arenites of the southern thrace basin are mostly lithic arkoses and arkosic litharenites provenance from the izmir ankara and biga suture zones to the south is characterized by ophiolitic granitoid gneissic low grade metamorphic and extrabasinal carbonate rock fragments as well as by picotite and glaucophane the application of detailed petrographic observations for discriminating paleo vs neovolcanic and penecontemporaneous vs noncoeval terrigenous sands lead to a substantial revision of the geodynamic interpretation of the thrace basin formerly considered a forearc basin a significant penecontemporaneous volcanic component is common in the upper eocene lower oligocene section and can be related to extensive post collisional volcanism following the closure of the vardar izmir ankara ocean the coexistence of pure neovolcanic layers crystal tuffs and cinerites and hybrid arenites rich in penecontemporaneous carbonate grains with sands derived from a continental basement and ophiolitic suites indicates the presence of episutural basins where shallow water carbonates were deposited on top of the exhuming subduction accretion prism these carbonates were mixed with penecontemporaneous neovolcanic and terrigeneous components and redeposited in deeper marine environments

late cenozoic extension in northeastern greece strymon valley detachment system and rhodope metamorphic core complex the strymon valley detachment system accommodated at least 25 km of extension at the northern margin of the aegean extensional province from middle miocene through early pliocene time the primary detachment surface is exposed as a gently southwest dipping low angle normal fault similar to those widely known in core complex settings of the u s basin and range province for more than 150 km along strike from the aegean sea coast in northeastern greece northward into the struma valley of southern bulgaria hanging wall rocks in the strymon valley detachment system moved in a s53 w direction relative to the footwall resulting ultimately in the tectonic unroofing of the rhodope metamorphic core complex several segments of the strymon valley detachment have previously been interpreted as thrust faults formed during a miocene compressional event our results negate the principal evidence for this event and imply instead that extensional deformation has characterized the northern aegean region since at least middle miocene time displacement ceased on the strymon valley detachment with the late pliocene development of the strymon and drama basins we propose that those basins together with the other principal basins of the northern aegean region are subsiding above an active northeast dipping extensional detachment zone that forms a unified kinematic system with the western offshore continuation of the dextral north anatolian strike slip fault the north aegean trough if this hypothesis is correct then the north aegean trough the western strands of the north anatolian fault and the principal modern depocenters of the northern aegean region may all have originated no earlier than late pliocene time

aegean tectonics strain localisation slab tearing and trench retreat abstract we review the geodynamic evolution of the aegean anatolia region and discuss strain localisation there over geological times from late eocene to present crustal deformation in the aegean backarc has localised progressively during slab retreat extension started with the formation of the rhodope metamorphic core complex eocene and migrated to the cyclades and the northern menderes massif oligocene and miocene accommodated by crustal scale detachments and a first series of core complexes mccs extension then localised in western turkey the corinth rift and the external hellenic arc after messinian times while the north anatolian fault penetrated the aegean sea through time the direction and style of extension have not changed significantly except in terms of localisation the contributions of progressive slab retreat and tearing basal drag extrusion tectonics and tectonic inheritance are discussed and we favour a model 1 where slab retreat is the main driving engine 2 successive slab tearing episodes are the main causes of this stepwise strain localisation and 3 the inherited heterogeneity of the crust is a major factor for localising detachments the continental crust has an inherited strong heterogeneity and crustal scale contacts such as major thrust planes act as weak zones or as zones of contrast of resistance and viscosity that can localise later deformation the dynamics of slabs at depth and the asthenospheric flow due to slab retreat also have influence strain localisation in the upper plate successive slab ruptures from the middle miocene to the late miocene have isolated a narrow strip of lithosphere still attached to the african lithosphere below crete the formation of the north anatolian fault is partly a consequence of this evolution the extrusion of anatolia and the aegean extension are partly driven from below asthenospheric flow and from above extrusion of a lid of rigid crust

the late alpine evolution of an extensional shear zone naxos greece the mid miocene structural evolution of the metamorphic complex on naxos involved deformation in a kilometre scale low angle ductile shear zone the structures described are consistent with exhumation of the metamorphic complex during crustal extension after and possibly during localized high temperature barrovian style metamorphism non coaxial fabrics developed throughout the structural history indicate that upper levels were transported to the north during ductile extension this shear sense is opposite that inferred previously for the development cordilleran style metamophic core complexes in the cvclades ductile deformation was accompanied during its later stages by e w directed compression

timing aegean extension evidence from in situ u pb geochronology and cathodoluminescence imaging of granitoids from nw turkey abstract the biga peninsula of nw turkey hosts granitoid plutons that record the timing of extension in the aegean region here we focus on three plutons the kozak eybek and kestanbol and apply new methods to obtain a detailed tectonic history of their generation and exhumation in situ in thin section ion microprobe zircon geochronology and color cathodoluminescence cl imaging of zircon grains and whole thin sections show these granites experienced magma mixing brittle deformation and significant fluid rock interactions zircon ages range from the late eocene to late miocene with two ages from a single grain that are permian the late eocene early oligocene ages record the end stages of subduction during the closure of a branch of the neo tethyan ocean whereas late oligocene late miocene ages record the plutons extension and exhumation we present a model in which kozak eybek and kestanbol magmas were initially generated by fluid flux melting from dehydration of the subducting anatolide tauride block as evidenced by the late eocene to early oligocene ages late oligocene ages document the initiation of extension in the biga peninsula region and correlate to ages timing exhumation of the kazdag massif early miocene ages indicate continued aegean extension in the southern biga peninsula region at this time

a fore arc origin for the thrace basin nw turkey hydrocarbon bearing thrace basin occupies much of the european part of turkey the middle eocene to oligocene sequence in the centre of the basin exceeds 9 km in thickness based on the stratigraphy structure and the regional context of this basin we propose that it developed as a fore arc basin between the medial eocene and the oligocene above the northward subducting intra pontide ocean its post miocene history has been dominated mainly by wrench tectonics resulting from the activity of the now deactivated northwestern strand of the present day north anatolian fault zone

coeval plutonism and metamorphism in a latest oligocene metamorphic core complex in northwest turkey a metamorphic core complex of latest oligocene age crops out in the kazdag mountain range in northwest turkey the footwall of the core complex consists of gneiss amphibolite and marble metamorphosed at 5 1 kbar and 640 50 c the average muscovite and biotite rb sr ages from the gneisses are 19 ma and 22 ma respectively and imply high temperature metamorphism during latest oligocene times the hangingwall is made up of an unmetamorphosed lower tertiary oceanic accretionary melange with upper cretaceous eclogite lenses the hangingwall and footwall are separated by an extensional ductile shear zone two kilometres thick mylonites and underlying high grade metamorphic rocks show a n trending mineral lineation with the structural fabrics indicat ing down dip top to the north shear sense the shear zone the accretionary melange and the high grade metamorphic rocks are cut by an undeformed granitoid with a 21 ma rb sr biotite age analytically indistinguishable from the rb sr biotite ages in the surrounding footwall gneisses the estimated pressure of the metamorphism and that of the granitoid emplacement indicate that the high grade metamorphic rocks were rapidly exhumed at 24 ma from a depth of 14 km to 7 km by activity along the shear zone the subsequent exhumation of the metamorphic rocks to the surface occurred during pliocene quaternary times in a transpressive ridge between two overstepping fault segments of the north anatolian fault zone the high grade metamorphic rocks of the kazdag range are surrounded by voluminous calc alkaline volcanic and plutonic rocks of late oligocene early miocene age which formed above the northward dipping hellenic subduction zone the magmatic arc setting of the core complex and stratigraphic evidence for subdued topography in northwest turkey prior to the onset of extension suggest that the latest oligocene regional extension was primarily related to the roll back of the subduction zone rather than to the gravitational collapse

a comparison of geodetic and finite strain pattern in the aegean geodynamic implications abstract a comparison of the active strain pattern of the aegean constrained by global positioning system measurements and the oligo miocene finite strain field shows some striking similarities in terms of direction and rates of extension the geometry of extension at crustal scale is also very similar with north dipping normal faults connecting near the brittle ductile transition to shallow north dipping shear zones this pattern of extension is not significantly modified by the recent extrusion of the motion of anatolia and aegea the persistence over more than 25 myr of the same pattern of extension suggests that the cause for extension resides within the aegean lithosphere gravitational collapse allowed by extensional boundary conditions after 30 ma slab retreat is the primary cause for post orogenic extension in the aegean and western anatolia

the 40ar 39ar age of extensional ductile deformation and granitoid intrusion in the northern menderes core complex implications for the initiation of extensional tectonics in western turkey the simav detachment fault in the northern part of menderes core complex in western turkey separates cover sequence rocks with brittle deformation from high grade metamorphic core rocks and young granitoid intrusions the timing of shear zone formation and the intrusion of syn tectonic granitoids is constrained by 40ar 39ar geochronology on muscovite from mylonitic gneiss and biotite from the egrigoz granitoid 40ar 39ar data indicate that mylonitic deformation occurred at 22 86 0 47 ma whilst the cooling age of the granitoid is 20 19 0 28 ma the intrusion and cooling of the egrigoz granitoid occurred between 23 20 ma these data demonstrate that extensional deformation in the northern menderes core complex began before early miocene times and represents an early stage in the tertiary extensional tectonics of western turkey

the rhodope zone as a primary sediment source of the southern thrace basin ne greece and nw turkey evidence from detrital heavy minerals and implications for central eastern mediterranean palaeogeography detrital heavy mineral analysis coupled with a regional geological review provide key elements to re evaluate the distribution of the rhodope metamorphic zone se europe in the region and its role in determining the evolution of the thrace basin we focus on the eocene oligocene sedimentary successions exposed in the southern thrace basin margin to determine the dispersal pathways of eroded crustal elements of both oceanic and continental origins as well as their different contributions through time lithological aspects and tectonic data coupled with geochemistry and geochronology of metamorphic terranes exposed in the area point to a common origin of tectonic units exposed in nw turkey biga peninsula with those of ne greece and se bulgaria rhodope region the entire region displays 1 common extensional signatures consisting of comparable granitoid intrusion ages and a ne sw sense of shear 2 matching zircon age populations between the metapelitic and metamafic rocks of the circum rhodope belt ne greece and those of the camlica kemer complex and cetmi melange exposed in nw turkey detrital heavy mineral abundances from eocene oligocene sandstones of the southern thrace basin demonstrate the influence of two main sediment sources mostly of ultramafic ophiolitic and low to medium grade metamorphic lithologies plus a third volcanic source limited to the late eocene oligocene detrital cr spinel chemistry is used to understand the origin of the ultramafic material and to discriminate the numerous ultramafic sources exposed in the region compositional and stratigraphic data indicate a major influence of the metapelitic source in the eastern part gallipoli peninsula during the initial stages of sedimentation with increasing contributions from metamafic sources through time on the other hand the western and more external part of the southern thrace margin gokceada samothraki and limnos displays compositional signatures according to a mixed provenance from the metapelitic and metamafic sources of the circum rhodope belt camlica kemer complex and cetmi melange tectonic restoration and compositional signatures provide constraints on the palaeogene palaeogeography of this sector of the central eastern mediterranean region

rapid early middle miocene exhumation of the kazdag massif western anatolia apatite fission track analyses indicate that the kazdag massif in northwestern anatolia was exhumed above the apatite partial annealing zone between 20 and 10 ma i e early middle miocene with a cluster of ages at 17 14 ma the structural analysis of low angle shear zones high angle normal faults and strike slip faults as well as stratigraphic analysis of upper plate sedimentary successions and previous radiometric ages point to a two stage structural evolution of the massif the first stage encompassing much of the rapid thermal evolution of the massif comprised late oligocene early miocene low angle detachment faulting and the associated development of small supradetachment grabens filled with a mixture of epiclastic volcaniclastic and volcanic rocks kucukkuyu fm the second stage plio quaternary has been dominated by i strike slip faulting related to the westward propagation of the north anatolian fault system and ii normal faulting associated with present day extension this later stage affected the distribution of fission track ages but did not have a component of vertical normal movement large enough to exhume a new partial annealing zone the thermochronological data presented here support the notion that neogene extensional tectonism in the northern aegean region has been episodic with accelerated pulses in the early middle miocene and plio quaternary

multiple exhumation phases in the central pontides n turkey new temporal constraints on major geodynamic changes associated with the closure of the neo tethys ocean

stress coupling between earthquakes in northwest turkey and the north aegean sea we have investigated the coulomb stress interactions of 29 earthquakes m s greater than or equal to 6 0 that have occurred in the region of northwest turkey and north aegean sea since 1912 of these events 23 may be related to earlier events and 16 are clearly related to earlier events all events after 1967 are related to previous events events in the early part of our time interval that show no correlation could be related to historical events as yet unidentified in some cases faults that have received a stress reduction from earlier events are prepared for an event by an earthquake occurring a few years before that creates a local coulomb stress rise thus regions of coulomb stress shadow can become regions where a damaging earthquake may occur the relation between smaller events and the coulomb stress distribution is less clear but may be related to poor data quality and practical limitations of our modeling technique nonetheless there are 4 times as many events per unit area in regions of enhanced stress than where stress is reduced we discuss the contemporary distribution of coulomb stress and argue that it is possible to identify the likely locations of future damaging earthquakes including identifying the most likely candidate faults

the bursa gonen depression nw turkey a complex basin developed on the north anatolian fault in this study we show that the southern branch of the north anatolian fault has been active since late pliocene time and that evidence of activity is supported by geological and seismological data the southern branch of the north anatolian fault consists of four segments from west to east yenice gonen manyas mustafakemalpasa uluabat and bursa these faults delimit the bursa gonen depression with the bandirma mudanya uplift to the north and uludag sularya uplift to the south the bursa gonen depression includes upper pliocene to recent sediments that thicken to the south suggesting a deposition pattern under active fault control study of fault kinematics suggests that the bursa gonen depression started as a small pull apart basin during late pliocene time and then evolved to a large depression the faults delimiting this depression are still active and capable of producing future earthquakes

evidence from the gediz graben for episodic two stage extension in western turkey western turkey falls within a wide belt of nne ssw directed active continental extension generally similar to the basin and range province of the usa it comprises a zone of wnw ese trending major grabens detailed study of the gediz graben reveals two contrasting infills that represent two distinct extensional stages separated by a short phase of compression the older infill consists of an 800 m thick folded and exhumed continental sedimentary sequence with intercalated calc alkaline volcanics it accumulated in a basin formed in the northern hanging wall of a detachment fault during miocene early pliocene times the younger infill rests on the older infill with angular unconformity and consists of about 170 m of undeformed terraced continental sediments and basaltic lavas it accumulated during plio quaternary times in an asymmetric graben bounded by step like normal faults this later extension was probably triggered by the commencement of sea floor spreading along the red sea in early pliocene times and has persisted to the present almost all the grabens in western turkey are best explained by this episodic two stage graben model with an intervening phase of short term compression which differs from the progressive evolution inferred for the basin and range province of the usa

zircon u pb ages and hf o isotopic composition of migmatites from the zanjan takab complex nw iran constraints on partial melting of metasediments abstract we study migmatites and other metamorphic rocks in the zanjan takab region of nw iran and use these results to report the first evidence of oligocene core complex formation in iran four samples of migmatites associated with paragneisses including leucosomes and associated para amphibolite melanosomes were selected for u pb dating and hf o isotopic analysis zircon cores interpreted as originally detrital zircons have variable ages that peak at ca 100 110 ma but their sedimentation age indicated by the youngest 206 pb 238 u ages is ca 35 40 ma new zircons associated with incipient melting occur as overgrowths around zircon cores and or as newly grown grains morphologies and internal structures suggest that rim growth and formation of new zircons were associated with partial melting all four samples contain zircons with rims that yield 206 pb 238 u ages of 28 25 ma indicating that partial melting occurred in late oligocene time 18 o values for zircon rims vary between 8 2 and 12 3 significantly higher than expected for mantle inputs 18 o 6 and consistent with equilibrium with surface materials zircon rims yield ehf t between 2 2 and 12 4 and two stage hf model ages of 448 562 ma indicating that the region is underlain by cadomian caledonian crust according to the hf o isotopic values the main mechanism forming zircon rims was dissolution of pre existing detrital zircons with reprecipitation of new zircon shortly thereafter oligocene ages indicate that partial melting accompanied core complex formation in the zanjan takab region extension melting and core complex formation in south central iran are eocene in age but younger ages of oligocene miocene in nw iran and turkey indicate that extension was distributed throughout the region during cenozoic time

timing of cenozoic extensional tectonics in west turkey the timing of the transition from compressional to extensional tectonics in the late cenozoic evolution of west turkey has been constrained by k ar geochronology from acidic volcanic rocks and tourmaline leucogranite dykes in the central and east margin respectively of the gordes basin dacites and rhyolites in the centre of the gordes neogene sedimentary basin cut both the basement ophiolites of the izmir ankara suture zone and the neogene sediments on the basin s eastern margin the leucogranites cut metamorphic basement along a major ne sw trending normal fault that controls the regional structure of the basin pebbles of these leucogranites occur in adjacent neogene turfites and conglomerates k ar dates on biotites from the central volcanic rocks vary from 18 4 0 8 ma to 16 3 0 5 ma early miocene whilst muscovite from a leucogranite on the eastern margin of the basin provides ages of 24 2 0 8 ma and 21 1 1 1 ma latest oligocene to early miocene geochronological data and field relationships demonstrate that the earlier compressional regime had been replaced by extensional tectonics by latest oligocene early miocene

a prospective sector in the tethyan metallogenic belt geology and geochronology of mineral deposits in the biga peninsula nw turkey abstract the tethyan metallogenic belt tmb extending from europe through anatolia to iran is one of the world s major metal producing belts and consists of many sectors mineral deposits of the biga peninsula in northwestern turkey exhibit in many ways the characteristics of mineral deposits found throughout the belt biga peninsula tectonically forms the westernmost part of the sakarya zone and easternmost part of the rhodope zone at the intersection of gondwana and laurasia the biga peninsula metallogeny research and exploration project created a gis inventory of mineral deposits and prospects and classified them genetically to evaluate the mineral deposit potential using genetic models based on descriptive data the gis database consisting of 128 deposits or prospects helped to generate new prospects and potential prospects this field based study indicated that the biga peninsula forms a prime target for gold copper exploration not only in turkey but in the world the current economically significant mineral deposits of the biga peninsula were shaped by cenozoic calc alkaline magmatism ranging between 52 and 18 ma and related to mainly collisional and post collisional tectonic regime epithermal au ag deposits including high hs low ls and intermediate sulfidation is styles porphyry au cu mo and base metal skarn systems are economically the most important though there are no currently economic examples of some of them in the biga peninsula other deposit types include carlin like distal disseminated au ag orogenic au especially listwanite hosted volcanogenic mn and u lateritic ferricrete fe deposits carbonate replacement cr and placers several active metal mines such as balya arapucandere and koru are operating in the biga peninsula kucukdere au ag deposit in balikesir is the only gold mine in the biga peninsula except for by product gold produced from base metal deposits results of the study show current total gold endowment of the biga peninsula including reserves and or resources is 9 18 moz gold 284 2 t contained in twelve different deposits of these only 6 contain significant gold 0 3 moz or 10 t halilaga porphyry and agi dagi and kirazli hs epithermal systems have an ongoing resource estimate and halilaga is a candidate to be one of the largest cu au deposits not only in the biga peninsula but in turkey currently newly discovered tepeoba is the largest porphyry cu mo au deposit with known resources in the biga peninsula here the first 40 ar 39 ar step heating age data conducted on some of the major hs epithermal gold deposits and causative intrusives in the biga peninsula are reported geochronological results from this project evaluated with previous studies indicate at least 3 phases of porphyry and 2 phases of high sulfidation epithermal gold mineralization in the biga peninsula the most important mineralizing phases and related host rocks for gold mineralization range from 38 to 22 ma the oligocene is especially important for economic epithermal and porphyry systems in the biga peninsula which is comparable to deposits in the oligo miocene serbomacedonian rhodope metallogenic belt of the balkan peninsula in se europe

a precursor of the north anatolian fault in the marmara sea region abstract apatite u th he and fission track analyses of both basement and sedimentary cover samples collected around the marmara sea point to the existence of a system of major e w trending structural discontinuities active at least from the late oligocene in the early pliocene inception of the present day north anatolian fault naf system in the marmara region occurred by reactivation of these older tectonic structures this is particularly evident across the ganos fault in southern thrace as exhumation south of it occurred during the latest oligocene and north of it during the mid miocene in this area large tectonic structures long interpreted as the results of plio quaternary naf related transpressional deformation i e the ganos monocline the korudag anticline and the gelibolu folds were in fact produced during the late oligocene early miocene the overall lack of significant u th he age differences across the naf indicates that the early pliocene inception of strike slip motion in the marmara region represents a relatively minor episode at the scale of the entire marmara region the geographic pattern of exhumation ages shown in this study results instead from the complex superposition of older tectonic events including i the amalgamation of sakarya and anatolide tauride terranes and ii aegean related extension

formation of the late palaeozoic early mesozoic karakaya complex and related ophiolites in nw turkey by palaeotethyan subduction accretion several pre jurassic tectonic units in nw turkey are crucial to the current debate regarding the timing and direction of subduction of palaeotethys a major ocean that separated eurasia and gondwana in late palaeozoic early mesozoic times the most critical unit is the karakaya complex a deformed low grade assemblage of oceanic origin which comprises a nw verging se dipping stack of tectonostratigraphic units here interpreted as a palaeotethyan accretionary complex the units display lithologies consistent with origins in seamount trench abyssal and rifted carbonate platform settings clastic basin sequences developed on top of the complex other relevant tectonostratigraphic units in the area include ultrabasic rocks of supra subduction zone affinity which tectonically overlie permian carbonate platform units with intervening metamorphic soles and melanges restored structural trends suggest the presence of a southward dipping palaeotethyan subduction zone bordering gondwana related units during the late permian triassic this was probably additional to more important regional northward subduction along the southern margin of eurasia from the eastern mediterranean to the himalayas

accretionary prism forearc interactions as reflected in the sedimentary fill of southern thrace basin lemnos island ne greece architecture of the well exposed ancient forearc basin successions of northeast aegean sea greece provides useful insights into the interplay between arc magmatism accretionary prism exhumation and sedimentary deposition in forearc basins the upper eocene lower oligocene basin fill of the southern thrace forearc basin reflects the active influence of the uplifted accretionary prism deep marine sediments predominate the basin fill that eventually shoals upwards into shallow marine sediments this trend is related to tectonically driven uplift and compression field stratigraphic sedimentological petrographic geochemical and provenance data on the lower oligocene shallow marine deposits revealed the accretionary prism i e pindic cordillera or biga peninsula as the major contributor of sediments into the forearc region field investigations in these shallow marine deposits revealed the occurrence of conglomerates with 1 mafic and ultramafic igneous rock clasts 2 low grade metamorphic rock fragments and 3 sedimentary rocks the absence of felsic volcanic fragments rules out influence of a felsic source rock geochemical analysis indicates that the studied rocks were accumulated in an active tectonic setting with a sediment source of mainly mafic composition and palaeodispersal analysis revealed a ne nne palaeocurrent trend towards the rhodopian magmatic arc thus these combined provenance results make the accretionary prism the most suitable candidate for the detritus forming these shallow marine deposits

evolution of the bayramic magmatic complex northwestern anatolia abstract during the oligocene middle miocene period widespread magmatic activity developed in western anatolia following the continental collision between the sakarya continent and the tauride anatolide platform this produced both intrusive and extrusive rocks which appear to be associated in space and time as exemplified from the bayramic area in the bayramic area the magmatic activity started with the intrusion of the evciler granite and the coeval lower volcanic association this was followed by the development of the upper volcanic association these rock groups form collectively the bayramic magmatic complex which was generated under an on going north south compressional regime the bayramic magmatic complex has a subalkaline composition displaying a calcalkaline trend trace elements and ree contents resemble to island arc and collision related magmas according to the isotope values the bayramic magmatic complex was derived from the magmas of lithospheric mantle origin which were later contaminated while passing through the thick continental crust in a post collisional tectonic setting during the oligocene early miocene period the latest product of the magmatism is the late miocene pliocene basalt lavas their geochemical properties are clearly different from the oligocene early miocene magmatic rocks the basalts were generated when the north south compression gave way to the north south extensional regime

biostratigraphic data from the cetmi melange northwest turkey palaeogeographic and tectonic implications abstract the cetmi accretionary melange is cropping out in the biga peninsula of northwest turkey it is characterised by an isolated position relatively far from the accretion complexes of the nearest suture zones which raises the question of its lateral correlations a detailed biostratigraphic investigation of the limestone and radiolarite blocks and the matrix of the cetmi melange allowed to propose a solution for this palaeogeographic problem scarce red nodular limestones in the han bulog facies represent the oldest lithology in the melange their late scythian ladinian age is based on chiosella gondolleloides the co occurrence of gladigondolella sp and nicoraella cf kockeli and paragondolella fuelopi light grey limestone blocks are a characteristic feature of the cetmi melange they occur in two distinct facies facies a consists of packstone to grainstone and is characterised by unsorted and poorly washed pelbiosparites facies b consists of wackestone to packstone and is characterised by poorly washed biopelmicrites to biopelsparites the foraminiferal assemblage of facies a containing triasina hantkeni is of late norian to rhaetian age the foraminiferal assemblage of facies b never contains t hantkeni and is characteristic of a late triassic carnian to norian rhaetian age radiolarian cherts are widely distributed in the cetmi melange they record fully pelagic sedimentation from the upper bajocian to the aptian the matrix of the cetmi melange consists of brown to black shales sometimes silty or siliceous intercalated with dark grey greywackes palynomorphs of one sample of brownish silty shale yielded an early to middle albian age based on the co occurrence of several dinoflagellate cysts the age of the matrix representing the youngest lithology within the melange and of the unconformable overlaying section latest albian cenomanian indicate that the melange forming process stopped between the early albian and the latest albian cenomanian at a regional scale the cetmi melange has little in common with the melanges from the izmir ankara and intra pontide sutures of northwestern turkey precluding a direct correlation on the other hand the cetmi melange shares several characteristics with the melange like units of the eastern rhodope zone bulgaria and greece like a major cenomanian transgression the reworking of triassic limestones and middle jurassic lower cretaceous radiolarians and the absence of jurassic cretaceous passive margin lithologies the occurrence of rhodopian units on the biga peninsula suggests that the studied units represent an isolated fragment of the rhodope zone in nw turkey

evidence of early cretaceous remagnetization in the crimean peninsula a palaeomagnetic study from mesozoic rocks in the crimean and western pontides conjugate margins of the western black sea

morphometric age estimate of the last phase of accelerated uplift in the kazdag area biga peninsula nw turkey article i nfo while the plio quaternary uplift of the kazdag mountain range biga peninsula nw turkey is generally acknowledged little is known about its detailed timing partly because of this lack of data the cause of this uplift phase is also debated being associated either to back arc extension in the rear of the hellenic subduc tion zone to transpression along the northern edge of the west moving anatolian microplate or to extension driven by gravitational collapse here we perform a morphometric study of the fluvial landscape at the scale of the biga peninsula coupling the recently developed r sr analysis of the drainage network with concavity and steepness measures of a set of 29 rivers of all sizes while the dependence of profile concavity on basin size confirms that the landscape of the peninsula is still in a transient state the spatial distribution of profile steepness values characterized by higher values for streams flowing down from the kazdag massif shows that the latter undergoes higher uplift rates than the rest of the peninsula we obtain a sr value of 0 324 0 035 that according to the relation established by demoulin 2012 yields an age range of 0 5 1 3 ma and a most probable value of 0 8 ma for the time of the last tectonic perturbation in the region in agreement with the analysis of knickpoint migration in a subset of rivers this suggests that a pulse of uplift occurred at that time and corroborated by sparse published observations in the bayramic and canakkale depressions that the peninsula was uplifted as a whole from that time this uplift pulse might have been caused by transient compressive conditions in the anatolian plate when the eratosthenes seamount came to subduct beneath the cyprus arc around the early to mid pleistocene transition schattner 2010

a major oligo miocene detachment in southern rhodope controlling north aegean extension plutonic and metamorphic rocks of the southwest part of the rhodope massif in greece correspond to ductile lower crust exhumed and deformed along a major detachment during post thickening extensional tectonics extension started during the oligocene and is responsible for the development of miocene quaternary sedimentary basins both brittle and ductile deformations result from gravity collapse of previously thickened lithosphere as proposed for others large extended terranes this interpretation disagrees with the previous models which attributed tertiary ductile deformation to alpine thrusting and brittle extensional deformation to back arc tectonics above a subduction zone

reflection seismic study across the continental shelf of baba burnu promontory of biga peninsula northwest turkey abstract seismic and structural characteristics of the continental shelf of baba burnu promontory of biga peninsula northwest turkey were investigated by 67 km of multi channel seismic reflection survey interpretation of the seismic data indicates that the faults may be divided into two groups i in the southern area almost an e w trending major listric normal fault zone and subsidiary faults formed first and later a strike slip fault on the hanging wall of the major fault formed ii in the northern area a number of spatially developed parallel faults with major strike slip components are seen we propose that the gulf of edremit is a fault bounded basin which began to form in association with the generation of the e w trending faulting phase during the late miocene early pliocene

map view restoration of aegean west anatolian accretion and extension since the eocene 1 the aegean region greece western turkey is one of the best studied continental extensional provinces here we provide the first detailed kinematic restoration of the aegean region since 35 ma the region consists of stacked upper crustal slices nappes that reflect a complex paleogeography these were decoupled from the subducting african adriatic lithospheric slab especially since 25 ma extensional detachments cut the nappe stack and exhumed its metamorphosed portions in metamorphic core complexes we reconstruct up to 400 km of trench perpendicular ne sw extension in two stages from 25 to 15 ma the aegean forearc rotated clockwise relative to the moesian platform around euler poles in northern greece accommodated by extensional detachments in the north and an inferred transfer fault se of the menderes massif the majority of extension occurred after 15 ma up to 290 km by opposite rotations of the western and eastern parts of the region simultaneously the aegean region underwent up to 650 km of post 25 ma trench parallel extension leading to dramatic crustal thinning on crete we restore a detachment configuration with the mid cycladic lineament representing a detachment that accommodated trench parallel extension in the central aegean region finally we demonstrate that the sakarya zone and cretaceous ophiolites of turkey cannot be traced far into the aegean region and are likely bounded by a pre 35 ma n s fault zone this fault became reactivated since 25 ma as an extensional detachment located west of lesbos island the paleogeographic units south of the izmir ankara sava suture however can be correlated from greece to turkey

the geological signature of a slab tear below the aegean in this paper we explore the geology of the aegean region in the miocene to identify the geological signature of a first order slab tear observed in all tomographic models from 15 to 8 ma the tear is associated spatially and timely with a fast clockwise rotation of the external hellenides alkaline volcanism high temperature metamorphic domes with a predominance of north dipping detachments and south westward migration of granitoid intrusions these features suggest a warmer geodynamic environment during the rotation and the impact of a hot mantle flow associated with the tear the 8 ma duration between the first high temperature metamorphic domes in the centre of the archipelago and the beginning of the fast rotation may correspond to the time needed for the slab to bend stretch and finally tear

the aegean sea we summarize briefly the main features of a kinematic model of evolution of the aegean area since 13 ma the formation of the aegean sea by extensional tectonics is related to the subduction of the mediterranean floor below the hellenic arc we then make a quantitative estimate of vertical movements in the aegean area on the basis of geological data and demonstrate that the outer arc was built since the beginning of this episode of subduction by vertical uplift the easiest way to explain the uplift is by underplating finally we discuss briefly the dynamics of the subduction marginal sea formation processes in this continental collision framework

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

thermochronologic evaluation of postcollision extension in the anatolide orogen western turkey 1 to better understand the driving mechanisms behind the transition from collision to extension in a convergent orogen data from multiple low temperature thermochronometers were obtained from the simav detachment fault sdf the earliest developed major extensional structure recognized in the western anatolide orogen of western turkey twenty two zircon fission track ft 26 apatite ft 12 apatite u th he ages and 26 apatite ft track length analyses are presented the data establish that the sdf was a major extensional fault active between 25 and 19 ma the coincidence in timing of magmatism with cessation of sdf activity implies the detachment became locked owing to doming induced by magma emplacement zircon ft ages away from the influence of miocene magmatism record rapid footwall cooling between 25 and 21 ma at a slip rate of up to 15 km myr and demonstrate that active ductile deformation along the sdf migrated northward with time apatite ft ages from the footwall of the sdf are spatially invariant over 100 km and consistently 2 3 myr younger than the zircon fission track ages from the same samples these data are consistent with a regional but relatively rapid erosion linked cooling phase that removed 2 3 km of overburden following cessation of sdf activity but before deposition of sedimentary rocks on the detachment surface at 16 4 ma postcollision extension of the anatolide orogen with development of the sdf can be best explained as the result of postcollision magmatism and thermal weakening of the crust inducing the extensional reactivation of an earlier major out of sequence thrust

late miocene ductile extension and detachment faulting mykonos greece the geometry and style of structural relations at map to microscopic scale on mykonos cyclades aegean sea greece suggests ductile extension and detachment faulting during the late miocene this island is dominated by granitic rocks that have a well developed shallowly dipping mylonitic foliation and a northeast southwest trending mineral elongation lineation kinematic indicators in these rocks exhibit a top to the northeast down dip sense of shear textural relations suggest that conditions during mylonitic deformation were greenschist to amphibolite facies and published k ar geochronology suggests a late miocene age for this deformation event mylonitic rocks lie in the footwall of a low angle fault and fault striae parallel to the elongation lineation suggest kinematic coordination between mylonitic deformation and movement along the fault translation along the fault juxtaposes younger tilted sedimentary rocks of low metamorphic grade upon the once deeper mylonitic rocks the style and geometry of deformational fabrics and map relations on this island are strikingly similar to those observed in metamorphic core complexes of the western united states

s o and pb isotopic evidence on the origin of the inkaya simav kutahya cu pb zn ag prospect nw turkey abstract the inkaya cu pb zn ag prospect is a typical example of the hydrothermal mineralization occurring in the menderes massif which crop out in western anatolia the prospect located approximately 20 km west of simav kutahya turkey in northern part of the menderes massif have been characterized through the detailed examinations involving geological mineralogical whole rock geochemistry fluid inclusion stable isotope and lead isotope the inkaya cu pb zn ag prospect is located along an e w trending fault in the cambrian simav metamorphics which consist of quartz muscovite schist quartz biotite schist muscovite schist biotite schist and the arikayasi formation which is composed of marbles galena sphalerite chalcopyrite pyrite and fahlore are the main minerals and they are accompanied by small amounts of cerussite anglesite digenite enargite chalcocite covellite bornite and fe oxides with gangue quartz in addition to pb zn cu ag the ore samples contain substantial quantities of as cd and bi and small amount of au average contents of cu pb zn and ag are 77 400 ppm 102 600 ppm 6843 ppm and 203 ppm respectively the 34s values for galena chalcopyrite and pyrite formed in the same stage vary in the range from 1 7 to 2 1 average 2 0 0 1 to 0 3 average 0 2 and 1 5 to 2 6 average 1 5 respectively 34s values for h2s representing the composition of the fluids responsible for the sulfide mineral formations and calculated from the 34s value are between 2 77 and 1 33 it is consistent with the sulfur in sulfide minerals 18oquartz values range from 11 3 to 16 4 and estimated 18ofluid values range from 5 4 to 10 6 pyrite galena and pyrite chalcopyrite pairs calculated to determine equilibrium isotope temperatures based on 34s values are between 254 6 and 277 4 c for pyrite galena and 274 7 c for pyrite chalcopyrite sulfur and oxygen isotope values similar to the values for fluid equilibrated with an felsic magmatic source fluid inclusion studies on quartz of the same silicification stage coexisting with galena sphalerite and chalcopyrite collected from the mineralized vein indicate that the temperature range of the fluids is 235 c to 340 c and that the salinities are 0 7 to 4 49 wt nacl equivalent the wide range of homogenization temperatures and relatively lower salinities of the fluid inclusions indicate that at least two different fluid generations were trapped in the quartz from only one fluid type also lower salinities of fluid inclusion probably indicate mixing of meteoric water and magmatic fluid the galena has 206pb 204pb values of 18 862 18 865 207pb 204pb values of 15 707 15 711 and 208pb 204pb values of 39 033 39 042 the lead isotope values show a similarity with upper crustal values