uranium series dating of pedogenic silica and carbonate crater flat nevada a 230th 234u 238u dating study on pedogenic silica carbonate clast rinds and matrix laminae from alluvium in crater flat nevada was conducted using small sample thermal ionization mass spectrometry tims analyses on a large suite of samples though the 232th content of these soils is not particularly low mostly 0 1 9 ppm the high u content of the silica component mostly 4 26 ppm makes them particularly suitable for 230th u dating on single 10 to 200 mg totally digested samples using tims we observed that 1 both micro within rind and macro stratigraphic mappable deposit order of the 230th u ages were preserved in all cases 2 back calculated initial 234u 238u fall in a restricted range typically 1 67 0 19 so that 234u 238u ages with errors of about 100 kyr 2 could be reliably determined for the oldest 400 to 1000 ka rinds and 3 though 13 of the samples were 350 ka only three showed evidence for an open system history even though the sensitivity of such old samples to isotopic disruption is very high an attempt to use leach residue techniques to separate pedogenic from detrital u and th failed yielding corrupt 230th u ages we conclude that 230th u ages determined from totally dissolved multiple sub mm size subsamples provide more reliable estimates of soil chronology than methods employing larger samples chemical enhancement of 238u 232th or isochrons

drizzle in stratiform boundary layer clouds part ii microphysical aspects abstract this is the second of two observational papers examining drizzle in stratiform boundary layer clouds part i details the vertical and horizontal structure of cloud and drizzle parameters including some bulk microphysical variables in this paper the focus is on the in situ size resolved microphysical measurements particularly of drizzle drops r 20 m layer averaged size distributions of drizzle drops within cloud are shown to be well represented using either a truncated exponential or a truncated lognormal size distribution the size resolved microphysical measurements are used to estimate autoconversion and accretion rates by integration of the stochastic collection equation sce these rates are compared with a number of commonly used bulk parameterizations of warm rain formation while parameterized accretion rates agree well with those derived from the sce initialized with observed spectra the autoconversion rates seriously disagree in some cases these disagreements need to be addr

cloud radar doppler spectra in drizzling stratiform clouds 1 forward modeling and remote sensing applications 1 several aspects of spectral broadening and drizzle growth in shallow liquid clouds remain not well understood detailed cloud scale observations of microphysics and dynamics are essential to guide and evaluate corresponding modeling efforts profiling millimeter wavelength cloud radars can provide such observations in particular the first three moments of the recorded cloud radar doppler spectra the radar reflectivity mean doppler velocity and spectrum width are often used to retrieve cloud microphysical and dynamical properties such retrievals are subject to errors introduced by the assumptions made in the inversion process here we introduce two additional morphological parameters of the radar doppler spectrum the skewness and kurtosis in an effort to reduce the retrieval uncertainties a forward model that emulates observed radar doppler spectra is constructed and used to investigate these relationships general analytical relationships that relate the five radar observables to cloud and drizzle microphysical parameters and cloud turbulence are presented the relationships are valid for cloud only cloud mixed with drizzle and drizzle only particles in the radar sampling volume and provide a seamless link between observations and cloud microphysics and dynamics the sensitivity of the five observed parameters to the radar operational parameters such as signal to noise ratio and doppler spectra velocity resolution are presented the predicted values of the five observed radar parameters agree well with the output of the forward model the novel use of the skewness of the radar doppler spectrum as an early qualitative predictor of drizzle onset in clouds is introduced it is found that skewness is a parameter very sensitive to early drizzle generation in addition the significance of the five parameters of the cloud radar doppler spectrum for constraining drizzle microphysical retrievals is discussed

southward migration of arc magmatism during latest cretaceous associated with slab steepening east pontides n turkey new paleomagnetic data from the amasya region abstract a new paleomagnetic study was carried out on the findikli formation in the amasya region which is to the north of the ankara erzincan neotethyan suture zone in order to better understand the paleogeographic evolution of the pontides tectonic belt during the maastrichtian samples were collected from volcanoclastic sandstones and lavas at 51 sites rock magnetic experiments identified pseudo single domain psd titanomagnetite as the main magnetic carriers at the majority of sites progressive thermal and alternating demagnetization revealed that the characteristic remanent component is removed between 400 and 580 c or 20 100 mt respectively a high temperature component which indicates the presence of titano hematite is found only in some lavas declinations show a systematic dispersion across the study area related to tectonic rotations about vertical axes inclinations are consistent however and yield a mean paleolatitude of 20 0 n 2 5 for the maastrichtian comparison of the results from this study with the reference direction of the east pontides from the turonian campanian is best explained with a model involving slab roll back and marginal basin formation between 90 and 65 ma period

upper crustal emplacement and deformation of granitoids inside the uppermost unit of the cretan nappe stack constraints from u pb zircon dating microfabrics and paleostress analyses the present study is dealing with the emplacement and deformation of diorite and quartz diorite exposed along new road cuts between agios nikolaos and sitia uppermost unit eastern crete mingling of both melt types is indicated by enclaves of diorite inside quartz diorite and vice versa the diorite and quartz diorite intruded into coarse grained white marble which is in lateral contact to but also forms the roof of the intrusive body evidence for contact metamorphism is indicated by increasing grain size of calcite in the marble with decreasing distance from the diorite u pb tims dating of zircons separated from quartz diorite yielded a concordant age at 74 0 0 25 ma which is interpreted as emplacement age as this age is close to published k ar cooling ages of hornblende and biotite the melt should have intruded and cooled down rapidly at upper structural levels which is not common for granitoids of the uppermost unit of crete upper crustal melt emplacement is also documented by stoped blocks and by the lack of any ductile viscous deformation the diorite and quartz diorite however are affected by strong post oligocene brittle faulting paleostress analysis based on these faults revealed a change in stress field from n s and nnw sse shortening by thrusting convergence between african and european plates to nne ssw and ne sw shortening accommodated by strike slip sw ward extrusion of the anatolian microplate calcite twin density indicates high differential stress 260 20 mpa related to these phases of crustal shortening

validation and sensitivities of frontal clouds simulated by the ecmwf model abstract clouds simulated by the european centre for medium range weather forecasts ecmwf model are composited to derive the typical organization of clouds surrounding a midlatitude baroclinic system comparison of this composite of about 200 cyclones with that based on satellite data reveals that the ecmwf model quite accurately simulates the general positioning of clouds relative to a low pressure center however the optical depths of the model s high low clouds are too small large relative to the satellite observations and the model lacks the midlevel topped clouds observed to the west of the surface cold front sensitivity studies with the ecmwf model reveal that the error in high cloud optical depths is more sensitive to the assumptions applied to the ice microphysics than to the inclusion of cloud advection or a change of horizontal resolution from 0 5625 to 1 69 lat this reflects the fact that in the ecmwf model gravitational settling is the most rapid process controlling the abundance of ic

questions about myrmekite in deformed rocks abstract several questions about the development of myrmekite in deformed felsic and metapelitic rocks remain unanswered although a general relationship between deformation and myrmekite appears to be well established the fact that myrmekite grows into relatively non deformed k feldspar while being simultaneously deformed and recrystallized at the rear of the growing lobes suggests that strain energy may not be a major contributor to the advance of the growth interface of the myrmekite colony furthermore because myrmekite typically nucleates on existing plagioclase rather than in k feldspar strain energy may not contribute directly to nucleation of myrmekite either at least in many instances however strain energy probably contributes indirectly by facilitating access of fluids to growth sites thereby altering the local chemical environment and so promoting development of myrmekite because myrmekite recrystallizes readily in deformed felsic rocks it is one of the main contributors to the development of folia

geometry and kinematics of mykonos detachment cyclades greece evidence for slip at shallow dip 1 the eastern part of mykonos island cyclades greece shows the detailed internal structure of a two branch shallow dipping extensional detachment system of miocene age this paper shows that the last stage of slip along the detachment during the deposition of syn rift sediments occurred with a very low dip and proposes that this geometry prevailed since the initiation of extension extensional deformation during and after a 13 ma old granite intrusion is taken up by two main shallow dipping shear zones 1 the lower livada detachment which extends laterally across tinos island is a ductile structure located at the interface between the granite and the upper cycladic nappe metabasites a pervasive top to the ne shearing deformation is observed throughout the granite in this island with a strong gradient toward the intrusive contact later brittle faults shallowly and steeply dipping rework the ductile deformation with the same overall shear sense 2 the upper mykonos detachment is brittle and separates the metabasites from late miocene sandstones and conglomerates the detachment fault dips 12 15 toward the nne and its sense of shear is consistent with that of the livada detachment soft sediment deformation during the time of detachment faulting and the presence of steep normal faults that root into the detachment gouge indicate a shallow depth of deformation rotations about vertical and horizontal axes can be reconstructed within and below the detachment zone indicating that the overall direction of extension is nne ssw with a sense of shear toward the nne and the dip of the fault is throughout very low the two detachments have accommodated several tens of kilometers of horizontal extension during the formation of the aegean sea which emphasizes the importance of low angle extensional faults and shear zones in extensional tectonics

age and tectonic setting of bocsa and ocna de fier dognecea granodiorites southwest romania and of associated skarn mineralisation the granodiorite intrusion at ocna de fier dognecea in the western south carpathians romania triggered the formation of a classic fe pb zn skarn deposit the intrusive is related to the larger composite bocsa laccolith five kilometres north that is part of the regional banatite suite previous work indicated a k ar age of 65 57 ma and postulated an andean type subduction related tectonic setting for the intrusions we report ion probe u pb zircon ages of 79 6 2 5 ma for the bocsa laccolith and 75 5 1 6 ma for the ocna de fier pluton which date their emplacement fission track dating on titanite gives slightly younger ages 78 4 ma for bocsa and 73 4 ma for ocna de fier together with zircon and apatite data from the same samples average cooling rates of 52 c ma and 83 c ma are calculated for the bocsa and ocna de fier intrusives respectively a post collision tectonic setting is proposed on the basis of field evidence the timing of intrusions in the context of regional tectonic evolution and trace element geochemistry

tectonic controls on metamorphism partial melting and intrusion timing and duration of regional metamorphism and magmatism in the nigde massif turkey protracted heating and melting of orogenic middle crust followed by emplacement of a syn extensional pluton during decompression and cooling are demonstrated for a metamorphic core complex in central turkey new geochronologic data for the nigde massif of the central anatolian crystalline complex document an interval of melting crystallization and pb loss at elevated ambient temperature 85 92 ma determined by u pb shrimp within a single sample of peraluminous granite crustal melting was syn to post peak metamorphism 725 c dated at 91 0 2 0 ma by shrimp analysis of zircon rims in sillimanite schist that is part of the country rock to the pluton metamorphic monazite in sillimanite schist yields a younger age of 84 7 0 7 ma for matrix grains and inclusions in garnet hornblende 40ar 39ar ages from amphibolites interlayered with the sillimanite schists coincide with the timing of emplacement of magma into metamorphic country rock that had experienced cooling and decompression to 12 km and 550 c the similarity of 40ar 39ar ages for biotite in the pluton 79 ma and hornblende 79 81 ma biotite 74 76 ma and muscovite 78 83 ma in the metamorphic country rock document rapid cooling 100 c my following intrusion the coincidence of the youngest u pb magmatic zircon ages and the oldest 40ar 39ar ages combined with structural evidence for normal sense shearing and tectonic unroofing in the late cretaceous suggests that intrusion was driven by extension we propose that crustal melting occurred in the middle crust during prograde metamorphism and or initial decompression and that ascent and emplacement of magma as a pluton were only triggered once extension occurred and removed upper crustal rocks

cloud radar doppler spectra in drizzling stratiform clouds 2 observations and microphysical modeling of drizzle evolution sites is presented the evolution of the doppler spectra moments is consistent with the onset and growth of drizzle particles and can be used to assist modeling studies of drizzle onset and growth time height radar observations are used to exhibit the coherency of the doppler spectra shape parameters and demonstrate their potential to improve the interpretation and use of radar observations in addition a simplified microphysical approach to modeling the vertical evolution of the drizzle particle size distribution in warm stratiform clouds is described and used to analyze the observations the formation rate of embryonic drizzle droplets due to the autoconversion process is not calculated explicitly however accretion and evaporation processes are explicitly modeled the microphysical model is used as input to a radar doppler spectrum forward model and synthetic radar doppler spectra moments are generated three areas of interest are studied in detail early drizzle growth near the cloud top growth by accretion of the well developed drizzle and drizzle depletion below the cloud base due to evaporation the modeling results are in good agreement with the continental and maritime observations this demonstrates that steady state one dimensional explicit microphysical models coupled with a forward model and comprehensive radar doppler spectra observations offer a powerful method to explore the vertical evolution of the drizzle particle size distribution

phase boundary mobility in naturally deformed high grade quartzofeldspathic rocks evidence for diffusional creep abstract grain shape fabrics and optical microstructures of some quartzofeldspathic rocks deformed under upper amphibolite facies conditions in the southwestern grenville province ontario canada suggest that quartz and feldspar have accommodated intracrystalline plastic strains by both diffusional and dislocation creep in these rocks quartz and feldspar form polycrystalline domains separated by gently curved and locally cuspate phase boundaries whose morphology is similar in certain respects to the phase boundary morphology of rocks annealed experimentally under hydrostatic stress conditions in the naturally deformed rocks however phase boundary cusps consistently point along the foliation and parallel to the mineral fibre lineation i e in directions of inferred finite extension which implies that phase boundary motion and cusp formation occurred during deformation optical microstructures in feldspar and crystallographic preferred orientations in quartz are consistent with the accommodation of some intracrystalline plastic strains by dislocation creep however the morphology of quartz feldspar phase boundaries cannot be explained by either dislocation creep or static annealing alone we propose that phase boundary motion resulted from a diffusion assisted process involving dissolution at foliation parallel quartz feldspar phase boundaries mass transfer over length scales of the order of feldspar domain size 200 m or greater and precipitation at quartz feldspar phase boundary cusps this study extends the range of natural deformation conditions under which diffusional creep has been identified in quartzofeldspathic rocks it also has important implications for the natural rheological behavior of the mid and lower continental crust

new structural and u pb zircon data from anafi crystalline basement cyclades greece constraints on the evolution of a late cretaceous magmatic arc in the internal hellenides the asterousia crystalline complex consists of late cretaceous amphibolite facies metamorphic rocks and associated granitoids which can be found in exposures on crete and the cyclades greece it is attributed to the uppermost unit and therefore to the pelagonian domain of the internal hellenides the tectonometamorphic evolution of this unit is still a matter of debate we present new structural and petrological data of asterousia type rocks and greenschist facies metamorphic rocks from the island of anafi in the southern aegean sea as well as u pb zircon ages of granitoids from anafi the crystalline sequence of anafi rests on top of eocene flysch and comprises from bottom to top a anafi greenschist b anafi amphibolite group orthoamphibolite with intercalations of metasedimentary rocks at the base and c chalepa group amphibolite facies metasediments with slices of serpentinite and granitoids la icp ms and id tims 206pb 238u zircon ages of granodiorite from the chalepa group reveal several similar zircon populations suggesting continuous emplacement of granitoids inside a magmatic arc from ca 72 5 to 79 ma the minimum emplacement age of granodioritic magma deduced from the 206pb 238u median age of the youngest zircon population is 72 6 0 1 0 2 ma deformation micro fabrics of granodiorite result from low strain obtained at t 600 c this along with the u pb ages and published k ar ages indicates intrusion of the plutonic rocks at deep structural levels followed by very slow cooling monzogranitic dykes cutting through granodiorite in north eastern anafi are undeformed and yielded a 206pb 238u median age of 69 9 0 7 0 7 ma based on the new and published data the following implications for the tectonometamorphic evolution on anafi can be made 1 obduction and accretion of mantle slices serpentinite to the asterousia type rocks were prior to amphibolite facies metamorphism 2 intrusion of granitoids during the middle to late campanian within a magmatic arc setting and coeval shift of the magmatic arc towards the south 3 maastrichtian intrusion of dykes 4 palaeocene greenschist facies metamorphism and coeval ductile top to the se thrusting of the anafi amphibolite group on top of the anafi greenschist 5 post eocene brittle top to the se thrusting of the anafi greenschist and the anafi amphibolite group on top of flysch sediments 6 clockwise rotation of the system and early oligocene brittle top to the se thrusting of the chalepa group on top of all units mentioned above and 7 ongoing clockwise rotation of the aegean block during the oligocene to early miocene and change in stress field ne sw compression

contrasting deformation of s and i type granitoids in the lachlan fold belt eastern australia abstract several examples of contrasting deformation under greenschist facies conditions of closely associated silurian devonian s type peraluminous and i type mainly metaluminous granitoid plutons of very similar age occur in the lachlan fold belt of eastern new south wales australia they occur in and or near the wologorong batholith the wyangala batholith and the kosciusko batholith the s type granitoids generally are strongly foliated and locally mylonitic whereas most of the i type granitoids typically show alteration to hydrous minerals chlorite epidote and actinolite but are unfoliated or only locally weakly foliated commonly fractured and have spaced ductile shear zones the more obvious and penetrative deformation in the s type granitoids probably is due mainly to their larger contents of relatively weak and or ductile minerals especially quartz and biotite and to the common occurrence of quartz in relatively large patches these features providing more continuous strained volumes and enabling quartz and mica rich folia to develop between resistant grains of feldspar in most of the i type granitoids the smaller amounts of quartz and biotite together with the common occurrence of quartz in smaller more scattered patches produce more localized strained volumes and may give rise to local stress concentrations that lead to fracturing the latter provides access to fluids responsible for hydrothermal alteration however some i type granitoids have high enough proportions of less ductile minerals to develop foliations although typically this occurs only adjacent to major faults some variation in the deformation of s types also is to be expected thus the main factor controlling the development of foliations appears to be the ratio of strong to weak or brittle to ductile minerals rather than the s i subdivision with which it generally correlates although other possible factors need further investigation such contrasting styles of deformation could lead to the erroneous interpretation that the massive i types are post deformation plutons and that the s types which commonly are slightly older are foliated by syn emplacement deformation whereas in fact both are pre deformation granitoids

the cretan ophiolite bearing melange greece a remnant of alpine accretionary wedge abstract new data collected in central crete on the ophiolite bearing units result in a better understanding of the role and tectonic significance of these units in the construction of this segment of the hellenides these nappes are composed of three main tectonic units that characterized by different metamorphic facies conditions are represented by an un metamorphosed lower unit a greenschist to hp greenschist facies intermediate unit and a blueschist facies upper unit these chaotic thrust nappes include blocks of oceanic and continental deriving rocks and can be considered as a remnant of an accretionary complex the lower unit represents the toe of the wedge whereas the intermediate and upper units refer to the innermost and deeper subducted portions exhumed and superimposed on top of each other during the early stages of continental collision the structural evolution of the accretionary wedge was controlled by four main contractional deformation events that including distinct groups of structures developed at different crustal levels were driven by sse and ssw directions of tectonic transport our data strongly suggest that the ophiolite bearing tectonic wedge was accreted during the paleogene subduction of a late jurassic cretaceous oceanic realm beneath the continental margin of the pelagonian domain and it was successively involved in the continental collision with the adria block the greenschist to blueschist facies metamorphism and the subsequent exhumation and emplacement of the intermediate and upper units above the frontal portion of the wedge may mainly be due to deep duplexing marking the onset of continental collision we thus suggest that the ophiolite bearing units of crete represent a single suture zone related to the closure of a unique oceanic domain pindos cycladic ocean subducted beneath the internal hellenides platform continental domains thus assuming the significance of a southern oceanic seaway of the largest eastern neotethys developed since the triassic between eurasia and africa

the turbulence structure in a continental stratocumulus cloud from millimeter wavelength radar observations abstract the turbulent scale vertical velocity structure in a continental stratocumulus cloud is studied using a 3 mm wavelength doppler radar operating in a vertically pointing mode the radar observations provided 30 m sampling in the vertical with 2 s averages of 10 000 samples vertical velocity measurements were made continuously for an 8 h period and were further supported by measurements of cloud base height from a laser ceilometer and liquid water path from a microwave radiometer during the beginning of the observational period the cloud layer extended between 200 and 800 m the vertical velocity variance profiles evolved systematically over the period from a well defined peak in the upper part of the cloud layer of 0 7 m2 s 2 to a peak in the lower part of the cloud layer of 0 2 m2 s 2 as the layer became decoupled later in the observing period the vertical velocity skewness during the well coupled conditions was negative through most of the cloud consistent with the presence of relatively n

geochemical sedimentary and micropaleontological evidence for a late maastrichtian oceanic seamount within the pindos ocean arvi unit s crete greece abstract we test the model of bonneau 1984 who hypothesised that the arvi unit in southern crete represents upper cretaceous oceanic crust of a pindos oceanic basin the arvi unit is dominated by basaltic lava flows pelagic carbonates and terrigenous sandstone turbidites the enriched within plate type geochemistry of the basaltic lavas is consistent with a seamount setting the subaqueous lava structures and associated pelagic carbonates further justify a seamount origin peperites composed of lava pelagic carbonate mixtures date the arvi unit as late maastrichtian using diagnostic planktic foraminifera the lavas are overlain by pelagic carbonates also of late maastrichtian age that then pass gradationally upwards into sand to pebble grade gravity flows the clastic sediments contain grains derived from several sources namely continental metamorphic and plutonic ophiolite related e g serpentinite gabbro diabase deep sea e g chert pelagic carbonate and shallow marine e g shell fragments the terrigenous detritus is inferred to have come from the pelagonian microcontinent unit asteroussia nappe then to the northeast where ophiolites and deep sea sediments were obducted during late jurassic time the inferred arvi seamount was accreted at the southeasterly subducting active margin of the pelagonian microcontinent after maastrichtian time related to closure of the pindos ocean the new evidence from the arvi unit provides additional evidence for the existence of the pindos ocean between the apulian and pelagonian continental units in the greece albania region

prism and basal plane parallel subgrain boundaries in quartz a microstructural geothermobarometer empirical data on quartz subgrain patterns from various metamorphic rocks show that at least up to 10 kbar in the stability field of low quartz prismatic subgrain boundaries are dominant whereas basal subgrain boundaries are not developed in the high quartz stability field both prismatic and basal subgrain boundaries occur and form typical rectangular chessboard patterns the likely reason behind the different occurrence of these subgrain patterns is that in high quartz prismatic glide becomes as easy as or probably even easier than basal glide the two types of subgrain patterns can be clearly distinguished by optical microscopy consequently the occurrence of chessboard subgrain patterns in quartz represents a practicable geothermobarometer the possibilities of its application are far reaching and include the specification of deformation conditions at high grade metamorphism the recognition of syntectonic intrusions and the distinction between pluton emplacement at lower and at higher crustal levels

mesoscale variability in denmark strait the pv outflow hypothesis abstract the outflow through denmark strait shows remarkable mesoscale variability characterized by the continuous formation of intense mesoscale cyclones just south of the sill these cyclones have a diameter of about 30 km and clear signatures at the sea surface and in currents measured near the bottom they have a remnant of arctic intermediate water aiw in their core the authors hypothesis is that these cyclones are formed by stretching of the high potential vorticity pv water column that outflows through denmark strait the light upper layer of the outflow the east greenland current remains on the surface in the irminger sea while the dense overflow water descends the east greenland continental slope the midlevel waters mostly aiw could thus be stretched by more than 100 which would induce very strong cyclonic relative vorticity the main test of this new hypothesis is by way of numerical experiments carried out with an isopycnal coordinate ocean model configured to have a marginal sea

on using the relationship between doppler velocity and radar reflectivity to identify microphysical processes in midlatitudinal ice clouds 1 ground based 35 ghz profiling doppler cloud radar observations of ice clouds were used to derive the power law relation between doppler velocity vd and radar reflectivity z vd azb by removing the vertical air motion from vd the power law can be rewritten as vt azb with vt being the reflectivity weighted particle terminal fall velocity profiles of this relation are variable with height an attempt was made to relate this variability to the dominant microphysical processes in different layers of the cloud based on that the possibility of using profiles of the parameters a and b to distinguish different microphysical regimes was explored the methodology was applied to long term measurements january 1997 to december 2010 at the atmospheric radiation measurement site in the southern great plains principal component analysis was used to determine the modes of the profiles that explain most of the observed variance in the observations profile averaged means and standard deviations of parameters a and b amounted to 0 65 0 42 and 0 03 0 19 respectively furthermore three commonly used microphysical relations related to bulk quantities were used to determine values of a and b these results were found to compare reasonably well with the values obtained from the radar observations finally microphysical considerations showed that radar derived values of parameter b can be explained in terms of particle size distribution moment changes

3 geochronology and geodynamics of late cretaceous magmatism and cu au mineralization in the panagyurishte region of the apuseni banat timok srednogorie belt bulgaria abstract the apuseni banat timok srednogorie abts belt europe s most extensive belt of calc alkaline magmatism and cu au mineralization is related to the subduction of the tethys ocean beneath the european continental margin during the late cretaceous phase of the alpine himalayan orogeny economic deposits are restricted to certain segments along the belt and all major porphyry style and high sulphidation ore deposits in bulgaria are aligned on the panagyurishte corridor a narrow zone obliquely crossing the abts belt this paper reviews the geology geochemistry and geochronology of igneous and hydrothermal events along this corridor in a profile extending from the european continental basement in the north to the accretionary complex of the rhodopes in the south extensive u pb dating of zircons from subvolcanic intrusions and major plutons supplemented by published age data for magmatic rocks and hydrothermal ore deposits obtained by other methods reveals a general younging of magmatism from ca 92 ma in the north elatsite to ca 78 ma in the south capitan dimitrievo cu au deposits are restricted to the northern and central parts of the profile ranging in age from 92 to 86 ma while the southernmost part exposes more deeply eroded mid crustal plutons devoid of economic mineralization the age progression correlates with a north to south geochemical trend of decreasing crustal input into mantle derived magmas magmatism and ore formation in individual magmatic hydrothermal complexes along the profile is much shorter lived for example subvolcanic intrusions and porphyry cu au mineralization at the elatsite deposit and andesitic volcanism and high sulphidation au as cu mineralization at chelopech all occurred within a time span of about 1 million years the age progression of calc alkaline magmatism within the panagyurishte region bulgaria from north to south is explained as a consequence of slab retreat during oblique subduction this led to transtensional block faulting and subsidence and thus to the preservation of near surface magmatic hydrothermal products including economic cu au deposits accretion of continental fragments in the rhodopes south of the abts belt led to greater uplift of the youngest late cretaceous intrusions this removed any ore deposits that might have been formed in this area