the exposed base of a collapsing wedge the nestos shear zone rhodope metamorphic province greece 1 the nestos shear zone nsz in the rhodope metamorphic province is a major high strain zone between two metamorphic terranes microdiamond bearing ultrahigh pressure uhp rocks occur in the nsz which was therefore interpreted as a suture zone where subduction and exhumation of these rocks and terrain accretion occurred during the mesozoic our petrological study of samples from the lower part of the nsz together with monazite dating of a microdiamond bearing garnet schist structural observations already published results from the upper part and other published timing constraints results in a fundamentally different picture the nsz is the base of an eocene age southwestward thrust wedge which included not only the structurally higher parts of the rhodope metamorphic province but also the entire internal hellenides the uhp rocks for the peak pressure of which we derive an age of 200 ma by monazite dating are unrelated to the tectonic processes in the nsz and probably represent slivers of a higher tectonic unit captured by thrusting along the nsz pressure decrease in the footwall and regional extension and basin formation in the hanging wall during the activity of the nsz show that the overlying thrust wedge was collapsing in late eocene times we hypothesize that the transition from subduction to continental collision may start with a pronounced accretion event when the first detachment horizon forms in the middle crust of the downgoing plate such an event could trigger slab retreat an extensional collapse of the internal wedge and subsequent magmatism

mesozoic tertiary structural evolution of an extensional gneiss dome the kesebir kardamos dome eastern rhodope bulgaria greece the tectonic evolution of the rhodope massif involves mid cretaceous contractional deformation and protracted oligocene and miocene extension we present structural kinematic and strain data on the kesebir kardamos dome in eastern rhodope which document early tertiary extension the dome consists of three superposed crustal units bounded by a low angle nne dipping detachment on its northern flank in bulgaria the detachment separates footwall gneiss and migmatite in a lower unit from intermediate metamorphic and overlying upper sedimentary units in the hanging wall the high grade metamorphic rocks of the footwall have recorded isothermal decompression direct juxtaposition of the sedimentary unit onto footwall rocks is due to local extensional omission of the intermediate unit structural analysis and deformational metamorphic relationships give evidence for several events the earliest event corresponds to top to the sse ductile shearing within the intermediate unit interpreted as reflecting mid late cretaceous crustal thickening and nappe stacking late cretaceous palaeocene eocene late tectonic to post tectonic granitoids that intruded into the intermediate unit between 70 and 53 ma constrain at least pre latest late cretaceous age for the crustal stacking event subsequent extension related deformation caused pervasive mylonitisation of the footwall with top to the nne ductile then brittle shear ductile flow was dominated by non coaxial deformation indicated by quartz c axis fabrics but was nearly coaxial in the dome core latest events relate to brittle faulting that accommodated extension at shallow crustal levels on high angle normal faults and additional movement along strike slip faults radiometric and stratigraphic constraints bracket the ductile then brittle extensional events at the kesebir kardamos dome between 55 and 35 ma extension began in paleocene early eocene time and displacement on the detachment led to unroofing of the intermediate unit which supplied material for the syn detachment deposits in supra detachment basin subsequent cooling and exhumation of the footwall unit from beneath the detachment occurred between 42 and 37 ma as indicated by mica cooling ages in footwall rocks and extension proceeded at brittle levels with high angle faulting constrained at 35 ma by the age of hydrothermal adularia crystallized in open spaces created along the faults this was followed by late eocene oligocene post detachment overlap successions and volcanic activity crustal extension described herein is contemporaneous with the closure of the vardar ocean to the southwest it has accommodated an earlier hinterland directed unroofing of the rhodope nappe complex and may be pre cursor of and or make a transition to the aegean back arc extension that further contributed to its exhumation during the late miocene this study underlines the importance of crustal extension at the scale of the rhodope massif in particular in the eastern rhodope region as it recognizes an early tertiary extension that should be considered in future tectonic models of the rhodope and north aegean regions

syn metamorphic nappe complex in the rhodope massif structure and kinematics mylonitic gneisses of the bulgarian and greek rhodope were deformed under medium pressure type metamorphism the kinematic information contained in these gneisses shows that shear deformation occurred during development of a nappe complex lithologies and metamorphic histories allow a lower footwall and an upper hanging wall terrane to be distinguished that define a crustal scale duplex as oceanic crust is involved collision between two continental units with subsequent crustal thickening is inferred the blocks would be moesia to the north and the lower rhodope promontory to the south which collided in the mesozoic to early cenozoic the nappe complex is characterized by south to southwestward foreland directed piling up and is associated with both coeval and subsequent extension the late extension is associated with the establishment of a high temperature low pressure metamorphic gradient and plutonism that predates but makes a transition to the lithospheric extension of the aegean arc

tectonometamorphic evolution of the rhodope orogen 1 this study combines new data on tectonostratigraphy macrostructures and microstructures petrology and geochronology to propose a comprehensive model for the tectonometamorphic evolution of the rhodope orogen from the jurassic to the early paleogene rocks from two study areas in the central and eastern greek rhodope represent a continental suture zone rhodope suture zone with the included material most likely forming an extensional allochthon south of the european continent during permo triassic times that was subsequently subducted beneath europe in the early jurassic 180 ma on the basis of comparable metamorphic ages and coherent structures but differences in metamorphic conditions and lithologies the rocks of the rhodope suture zone are subdivided into an upper and a lower part the prograde history is linked with subduction related structures in the lower part uniaxial stretching deformation stage d1 in metapelites the earliest stage of metamorphism recorded at circa 180 ma occurred at least under ultrahigh pressure metamorphic conditions the rocks of the upper part experienced isothermal decompression with partial anatexis exhumation paths of both parts differ in temperature because of the relative tectonic position within the exhuming wedge exhumation was forced by the nestos shear zone that controlled the early phase of normal displacement by sw shearing at the base lower part and ne shearing on top upper part from the late jurassic to the late cretaceous deformation stage d2 an intervening stage of mineral recrystallization and thermal reequilibration in the upper part was followed by a common exhumation history of both parts at pressures lower than about 12 kbar 35 40 km depth during this stage exhumation was controlled by southwest directed shearing and folding deformation stage d3 slab retreat to the south led to subsequent extension deformation stage d4 and final exhumation coeval with the formation of basement domes thus making the rhodope a classic core complex juxtaposed with former structurally higher units

exhumation of high pressure rocks driven by slab rollback rocks metamorphosed under high pressure hp and ultra high pressure uhp conditions in subduction zones come back to the surface relatively soon after their burial and at rates comparable to plate boundary velocities in the mediterranean realm their occurrence in several belts related to a single subduction event shows that the burial exhumation cycle is a recurrent transient process using the calabria apennine and aegean belts as examples we show that the exhumation of hp rocks is associated in time and space with the subduction of small continental lithosphere blocks that triggers slab rollback creating the necessary space for the exhumation of the buoyant continental crust that was deeply buried just before the buoyancy force of the subducted crust increases until this crust detaches from the downgoing slab it then exhumes at a rate that depends directly on the velocity of trench retreat to become part of the overriding plate heated from below by the asthenosphere that flows into the opening mantle wedge the exhumed crust weakens and undergoes core complex type extension responsible for a second stage of exhumation at a lower rate the full sequence of events that characterizes this model crust mantle delamination slab rollback and trench retreat hp rock exhumation asthenosphere heating and core complex formation arises entirely from the initial condition imposed by the subduction of a small continental block no specific condition is required regarding the rheology and erosion rate of hp rocks the burial exhumation cycle is transient and can recur every time a small continental block is subducted

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

structural and geochronological evidence for paleogene thrusting in the western rhodopes sw bulgaria elements for a new tectonic model of the rhodope metamorphic province 1 the rhodope metamorphic province in the area around the mesta graben sw bulgaria exposes a structurally lower complex the pangaion pirin complex of variscan continental crust and its cover mostly orthogneiss and marble and a higher complex the rhodope terrane of mixed oceanic and continental origin with metamorphosed jurassic arc magmatites the boundary between the two is the top to the southwest nestos shear zone the regional top to the southwest shearing of the two basement complexes is related to the emplacement of the rhodope terrane over the pangaion pirin complex along this shear zone syntectonic and posttectonic alpine intrusions within the basement can provide age limits for the thrusting zircons from the posttectonic teshovo south pirin granitoid pluton in the pangaion pirin complex yielded crystallization ages of 32 0 2 ma la sf icp ms u pb method zircons from two syntectonic granite plutons in the rhodope terrane dolno dryanovo and spanchevo have circa 143 to 145 ma old inherited magmatic cores and circa 55 to 56 ma old magmatic rims these ages especially the presence of the upper jurassic lower cretaceous cores in the plutons from the rhodope terrane and the structural relations indicate that the southwestward thrusting of the rhodope terrane over the pangaion pirin complex took place in the paleogene a model is proposed in which the pangaion pirin complex represents the margin of apulia and the structure of the rhodopes is explained by a switch of subduction polarity from sw dipping in the jurassic and early cretaceous to ne dipping in the late cretaceous and paleogene

the western alps from the jurassic to oligocene spatio temporal constraints and evolutionary reconstructions abstract despite extensive research in the last 150 years the regional tectonic reconstruction of the western alps has remained controversial the curved orogenic belt consists of several ribbon like continental terranes sesia austroalpine internal crystalline massifs brianconnais which are separated by two or more ophiolitic sutures piemonte valais antrona lanzo canavese high pressure hp metamorphism of each terrane occurred during distinct orogenic episodes at 65 ma in the sesia austroalpine at 45 ma in the piemonte zone and at 35 ma in the internal crystalline massifs it is suggested that these events reflect individual accretionary episodes which together with kinematic indicators and the speed and direction of plate motions provide constraints for the discussed reconstruction model the model involves a prolonged orogenic history that took place during relative convergence of europe and adria here considered as a promontory of the african plate the first accretionary event involved the sesia austroalpine terrane final closure of the piemonte ocean occurred during the eocene 45 ma and involved ultra high pressure uhp metamorphism of the piemonte oceanic crust incorporation of the brianconnais terrane in the accretionary wedge occurred thereafter possibly during or after subduction of the valais ocean in the late eocene 45 35 ma this subduction was terminated at ca 35 ma when the internal crystalline massifs i e the assumed internal parts of the brianconnais terrane were buried into great depths and underwent hp and uhp metamorphism

separate eocene early oligocene and miocene stages of extension and core complex formation in the western rhodopes mesta basin and pirin mountains bulgaria abstract the rhodope metamorphic province in bulgaria and northern greece has been affected by significant extensional tectonics since the middle to late eocene an important fault system active in the eocene and early oligocene includes the ribnovo fault on the eastern side of the mesta basin in bulgaria and the vertiskos kerdilion fault in greece together with several minor normal fault relicts identified during this study these represent an originally west southwest dipping low angle at least at the end of faulting normal fault with greenschist facies mylonites in the footwall and cataclasites along the fault plane the mesta kerdilion detachment exposed over ca 150 km along strike and about 50 km parallel to the slip direction during the intrusion of several plutons in the pirin mountains at ca 32 ma the footwall of the fault was uplifted to form a large anticline parallel to fault strike and the fault was offset by a system of antithetic northeast dipping normal faults along the northeastern flank of this anticline dobrotino and breznitsa faults the mesta kerdilion detachment was later in the miocene again crosscut and offset by the southwest dipping strimon valley detachment which accommodated important core complex like exhumation to the south strongly diminishing and finally ceasing towards north this rotational activity of the strimon valley detachment represents the onset of the extension that led to opening of the aegean basin the mesta kerdilion detachment can be viewed as a precursor of this but with slightly different kinematics i e not involving significant vertical axis rotation and separated in time from the following events by a phase of relative tectonic quiescence in the late oligocene

the isochron ray in seismic modeling and imaging the isochron the name given to a surface of equal two way time has a profound position in seismic imaging in this paper i introduce a framework for construction of isochrons for a given velocity model the basic idea is to let trajectories called isochron rays be associated with iso chrons in an way analogous to the association of conventional rays with wavefronts in the context of prestack depth migration an isochron ray based on conventional ray theory represents a simultaneous downward continuation from both source and receiver the isochron ray is a generalization of the normal ray for poststack map migration i have organized the process with systems of ordinary differential equations appearing on two levels the upper level is model independent and the lower level consists of conventional one way ray tracing an advantage of the new method is that interpolation in a ray domain using isochron rays is able to treat triplications multiarrivals accurately as opposed to interpolation in the dep

metamorphozed hercynian granitoids in the alpine structures of the central rhodope bulgaria geotectonic position and geochemistry abstract orthogneisses of late hercynian protolith age crop out in the central rhodope high grade metamorphic complex which is part of the alpine orogen in south eastern europe they compose a tectonic unit bordered by late alpine extensional shear zones these rocks reflect eocene amphibolite facies migmatization

fluid induced disturbance of the monazite th pb chronometer in situ dating and element mapping in pegmatites from the rhodope greece bulgaria abstract the monazite th pb chronometer is widely used in a variety of geological contexts but may be affected by interaction with fluids in the central part of the rhodope massif greece bulgaria synfolial pegmatite veins were emplaced within two major synmetamorphic shear zones in the chepelare shear zone czs which displays no evidence of post metamorphic fluid flow consistent monazite th pb ages of 36 ma are interpreted as dating vein emplacement higher in the metamorphic pile zircon and monazite give u th pb ages of 42 ma for vein emplacement in the nestos shear zone nsz pegmatites show evidence of post emplacement interaction with fluids during greenschist facies ductile deformation evidence for this includes the precipitation of calcite in microscale tension gashes within feldspar porphyroclasts and the oxygen isotope disequilibrium between quartz and feldspar aqueous carbonic fluids deriving from carbonate lithologies in the footwall of the nsz are identifiable in the pegmatites by the high 18 o value of quartz up to 21 8 and the presence of calcium in calcite veinlets in these samples some of the monazite grains show large intragrain scattering of th pb age spanning up to 12 ma with intergrain scattering reaching 16 ma from 39 to 55 ma within individual grains age domains correlate with chemical heterogeneities and some show a characteristic ca excess these chemical and isotopic alterations are interpreted to be caused by interaction with fluids derived from carbonate lithologies complementary u pb data on zircons from the nsz pegmatites yield mostly mesozoic ages related to an older metamorphic cycle and an age of 48 ma for one grain with typical magmatic zoning the th pb ages of 49 3 1 6 to 54 9 1 7 ma probably relate to the emplacement of the pegmatites the spread of younger th pb ages from 38 6 1 1 to 46 2 1 6 ma probably reflects the period of fluid circulation during progressive cooling to greenschist facies conditions or variable perturbations of the monazite isotope system during fluid assisted greenschist facies deformation this is consistent with 39 ar 40 ar mica ages of 32 to 34 ma interpreted as a tighter constraint for the timing of the greenschist facies metamorphism this study illustrates the capacity of monazite to record distinct events in a single rock and highlights the need for identifying the potential involvement of fluids in order to interpret monazite ages

evidence from the mesta half graben sw bulgaria for the late eocene beginning of aegean extension in the central balkan peninsula abstract the ene tilted mesta half graben contains a 3 km thick section of priabonian late eocene to oligocene sedimentary and volcanic rocks that rest unconformably on basement metamorphic rocks along its west side basal strata dip 50 60 e and dip at progressively lower angles upward indicating synrotational deposition the southern part of the half graben contains nested volcanic caldera complexes formed during the deposition of the middle part of the sedimentary sequence which have been rotated by about half the total rotation of the sedimentary succession the half graben is bounded on the east by a fault that steepens from more deeply exposed structural levels in the south 8 18 w to shallower exposed structural levels in the north 70 w and together with the rotation of paleogene strata during deposition indicate the mesta half graben is underlain by a listric detachment fault the mesta detachment subhorizontal middle miocene strata that unconformably overlie tilted paleogene strata yield an upper age limit to the extension west and northwest of the mesta half graben are many other nnw trending ne tilted paleogene half grabens which we suggest are part of an important extended area in sw bulgaria and eastern macedonia that lies above one or more west dipping detachment faults and date the beginning of aegean extension in the southern balkan region as at least as old as priabonian the mesta detachment is oblique to the trend of a contemporaneous paleogene magmatic arc in the southern balkans and the origin of the detachment is probably related to gravitationally induced spreading of thickened hot arc crust and hellenic trench roll back

subsidence and growth of pacific cretaceous plateaus abstract the ontong java manihiki and shatsky oceanic plateaus are among the earth s largest igneous provinces and are commonly believed to have erupted rapidly during the surfacing of giant heads of initiating mantle plumes we investigate this hypothesis by using sediment descriptions of deep sea drilling project dsdp and ocean drilling program odp drill cores to constrain plateau subsidence histories which reflect mantle thermal and crustal accretionary processes we find that total plateau subsidence is comparable to that expected of normal seafloor but less than predictions of thermal models of hotspot affected lithosphere if crustal emplacement was rapid then uncertainties in paleo water depths allow for the anomalous subsidence predicted for plumes with only moderate temperature anomalies and volumes comparable to the sources of modern day hotspots such as hawaii and iceland rapid emplacement over a plume head of high temperature and volume however is difficult to reconcile with the subsidence reconstructions an alternative possibility that reconciles low subsidence over a high temperature high volume plume source is a scenario in which plateau subsidence is the superposition of 1 subsidence due to the cooling of the plume source and 2 uplift due to prolonged crustal growth in the form of magmatic underplating this prolonged crustal growth and uplift scenario may explain the low and thus submarine relief during plume initiation the late stage eruptions found on ontong java 90 ma and manihiki 70 ma a large portion of the high seismic velocity lower crust and the widespread normal faults observed throughout and along the margins of the three plateaus such late stage underplating may have occurred continuously or in discrete stages over 30 m y and implies lower magmatic fluxes than previously estimated

cenozoic granitoids in the dinarides of southern serbia age of intrusion isotope geochemistry exhumation history and significance for the geodynamic evolution of the balkan peninsula two age groups were determined for the cenozoic granitoids in the dinarides of southern serbia by high precision single grain u pb dating of thermally annealed and chemically abraded zircons 1 oligocene ages kopaonik drenje eljin ranging from 31 7 to 30 6 ma 2 miocene ages golija and polumir at 20 58 20 17 and 18 06 17 74 ma respectively apatite fission track central ages modelling combined with zircon central ages and additionally local structural observations constrain the subsequent exhumation history of the magmatic rocks they indicate rapid cooling from above 300 c to ca 80 c between 16 and 10 ma for both age groups induced by extensional exhumation of the plutons located in the footwall of core complexes hence miocene magmatism and core complex formation not only affected the pannonian basin but also a part of the mountainous areas of the internal dinarides based on an extensive set of existing age data combined with our own analyses we propose a geodynamical model for the balkan peninsula the late eocene to oligocene magmatism which affects the adria derived lower plate units of the internal dinarides was caused by delamination of the adriatic mantle from the overlying crust associated with post collisional convergence that propagated outward into the external dinarides miocene magmatism on the other hand is associated with core complex formation along the southern margin of the pannonian basin probably associated with the w directed subduction of the european lithosphere beneath the carpathians and interfering with ongoing dinaridic hellenic back arc extension

geology and geochronology of the arnea sithonia and ouranopolis intrusions chalkidiki peninsula northern greece abstract the chalkidiki peninsula comprises the greek geotectonic units of the vardar axios zone and the serbo macedonian massif several granitic bodies of various ages intrude this area and many of them are of unknown or disputed age the ages of the arnea sithonia and ouranopolis granitoids are investigated using 40 ar 39 ar stepheated mineral and rb sr whole rock analyses the arnea granite has experienced intense but variable deformation recrystallization and retrogression in general it lacks easily datable minerals because of it s highly evolved silica rich composition however coarse grained phlogopitic mica separated from a minor less evolved porphyritic part of the intrusion yields an excellent 40 ar 39 ar plateau age of 136 1 ma rb sr whole rock samples give a regression line of age 155 11ma and an initial 87 sr 86 sr ratio of 0 7174 0 0017 mswd 280 the scatter may reflect the widespread recrystallization and deformation of the arnea granite the arnea granite is at least late jurassic in age and has undergone regional greenschist metamorphism during the early cretaceous biotite from the sithonia granitoid yields a plateau age of 43 0 6 ma muscovites from crosscutting pegmatites within the granitoid give slightly saddle shaped age spectra with minimum ages of 49 ma and 50 ma suggesting argon 40 excess biotite and muscovite from the ouranopolis granitoid yield plateau ages of 44 1 1 ma and 47 0 7 ma respectively it is suggested that this granitoid is coeval and cogenetic with the sithonia granitoid both intrusions are eocene in age rb sr whole rock samples from the sithonia and ouranopolis granitoids failed to provide any isochrons this is interpreted to be due to inhomogeneities in these young intrusions the age data strongly suggest that the sithonia and ouranopolis granitoids are unrelated to the arnea granite coupled with geochemical and petrographic data these results clarify the relationships between some of the granitic intrusions and have important regional implications

timing of tectonic emplacement of the ophiolites and terrane paleogeography in the hellenides the timing of tectonic emplacement of the ophiolites is analyzed in the four oceanic terranes of the hellenides h2 h4 h6 h8 the criteria for this analysis are based on a the post emplacement sedimentary cover or intrusive rocks b the syn emplacement tectonostratigraphic formations and c the youngest rocks involved in the structure of the autochthon and the allochthon unit in each case the timing becomes younger towards the more external tectonic units of the hellenides with i late eocene oligocene age in the external ophiolite belt of the pindos cyclades oceanic terrane h2 ii late jurassic early cretaceous age in the internal ophiolite belt of the vardar axios oceanic terrane h4 iii post liassic pre late jurassic age in the ophiolites of lesvos circum rhodope oceanic terrane h6 and iv pre late jurassic age in the ophiolites of volvi eastern rhodope terrane h8 an ophiolite obduction model can be applied with the ophiolitic nappes always emplaced on top of pre alpine continental terranes with mesozoic shallow water carbonate platforms the geometry of the continental terranes drifting during the mesozoic within the tethys ocean controls the number and dimensions of the tethyan oceanic basins where a continental terrane dies out the two adjacent oceanic basins merge into one larger basin this seems to be the case of the pelagonian terrane h3 which is terminated north of skopje where the pindos oceanic basin h2 merges with the vardar axios oceanic basin h4

high precision lu hf geochronology of eocene eclogite facies rocks from syros cyclades greece abstract garnet bearing high pressure low temperature hp lt metamorphic rocks of the cycladic blueschist unit have been investigated by lu hf geochronology eclogites from syros island yield precise ages of 52 2 0 3 ma 51 4 0 4 ma and 50 2 ma preserved major and trace element growth zoning in garnet suggests that the closure temperature of the lu hf system in garnet was higher than the estimated peak metamorphic temperature of 500 c hence lu hf ages most likely reflect garnet growth in the studied samples our new lu hf grt ages are in excellent agreement with previously published u pb shrimp ages of metamorphic zircon and the maximum reported white mica rb sr and ar ar ages from syros garnet growth in all samples apparently took place over a narrow time interval because the lu hf ages cluster tightly even though the distribution of lu between cores and rims varies among samples we find no evidence for garnet generations that are significantly older or younger than the given isochron ages this in conjunction with the agreement among the ages of metamorphic zircon the maximum white mica ages and the lu hf ages strongly suggests that the 52 ma age dates a single hp event that affected these rocks

thermodynamic properties of white micas on the basis of high pressure experiments in the systems k2omgoal2o3sio2h2o and k2ofeoal3o3sio2h3o abstract experiments in the piston cylinder apparatus were undertaken to synthesize the assemblage of phengite garnet kyanite and quartz or coesite in the system k2o mgo al2o3 sio2 h2o kmash compositional data of phengite were obtained for 13 experimental runs in the range of 30 to 45 kbar and 850 c to 1100 c the same was achieved for 23 runs in the system k2o feo al2o3 sio2 h2o kfash between 600 c and 900 c and 15 to 55 kbar on the basis of the latter runs and 6 additional synthesis experiments the dependence of the lattice dimensions on the composition of 2m1 phengites in kfash was determined to derive thermodynamic data we evaluated the above experiments and those reported by massonne and schreyer 1987 1989 on kmash phengites coexisting with other assemblages considering simple activity model like ams ms we obtained for the mg al celadonite and fe2 al celadonite theoretical endmembers hf0 5832415 3040 and 5492287 6267 j mol s0 288 527 4 008 and 303 148 6 827 j k mol v0 13 870 0 027 and 13 962 0 067 j bar mol the nonideal behavior of the muscovite ms mg al celadomite series was modelled using an asymmetric margules formalism with the following parameters w12h w21h 0 w12s 58 598 8 804 w21s 15 920 3 393 w12v 0 735 0 118 w21v 0 187 0 026 with units as above for the muscovite fe2 al celadonite series we used a symmetric model with wh 0 ws 24 083 3 088 j k mol and wv 0 3394 0 1120 j bar mol the above data were applied to construct a petrogenetic grid the example chosen is related to the kfash system with potassic white mica quartz and h2o in excess it covers the t range from 150 c to 550 c at a p up to 28 kbar the new thermodynamic data are also discussed in regard to their use in geothermobarometry

raman micro spectroscopy on diamond graphite and other carbon polymorphs from the ultrahigh pressure metamorphic kimi complex of the rhodope metamorphic province ne greece raman micro spectroscopy was applied on carbon inclusions in garnet porphyroblasts from kyanite biotite garnet schists of the rhodope metamorphic province rmp ne greece diamond and cuboids of poorly to highly ordered graphite were identified either as single phase inclusions or as polyphase inclusions along with co2 and or carbonates calcite magnesian calcite questionable raman bands that may be assigned to other c phases nanodiamond lonsdaleite a different c polymorph have been observed the presence of diamond confirms beyond any doubt the ultrahigh pressure uhp metamorphism reported by mposkos and kostopoulos 1 e mposkos d kostopoulos diamond former coesite and supersilisic garnet in metasedimentary rocks from the greek rhodope a new ultrahigh pressure metamorphic province established earth planet sci lett 192 2001 497 506 in the rmp cuboid graphite showing variable degree of disordering most probably formed after diamond the possible involvement of co2 and or c o h fluids in the formation of diamond is discussed