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

holocene palaeoclimates from peat stratigraphy macrofossil proxy climate records from three oceanic raised bogs in england and ireland quantified analyses of plant macrofossil remains have been made from three profiles of peat from raised bogs spanning a distance of 425 km from western ireland to northern england the reconstructed vegetation of each profile is related to changing bog surface wetness bsw and since the bogs are ombrotrophic these bsw changes are interpreted in terms of changing climate using age depth models based on a total of 49 radiocarbon dates a number of wetter and drier phases are identified and phase shifts to wetter and or cooler climates are defined prominent coincident changes to wetter conditions are dated in at least two of the profiles to ca 4400 4000 1750 1400 and 1000 cal bp and in all three profiles at 3200 2750 2350 2250 and around 700 cal bp these phases are related to proxy climate changes in other terrestrial data sets from northwest europe and a broad degree of synchroneity is demonstrated

backthrusting in accretionary wedges backthrusting of the rear of the accretionary wedge arcward over the rocks of the forearc basin is a common aspect of accretionary tectonics an older assumption that backstops of accretionary wedges dip back toward the arc and that accreted material is emplaced below such backstops is contradicted by observations from many active forearcs that indicate 1 backthrusting is common 2 forearc basins are nearly ubiquitous associates of accretionary wedges and 3 forearc basement where imaged appears to diverge from the sedimentary package dipping under the wedge while the overlying sediments are often lifted up against it backthrusting may be favored where relief is high between the crest of the wedge and the surface of the forearc basin because the relief must be supported by shear stress along the backthrust we find ratios of lt lb averaging 2 64 0 8 where lt is the horizontal distance from the crest of the wedge to the front of the toe and lb is the distance from the crest of the wedge to the surface projection of the backthrust this ratio is predicted to increase with total convergence and with sedimentation because the toe undergoes higher deformation rates than the backthrust and sedimentation in the trench favors outbuilding of the toe whereas sedimentation in the forearc basin tends to cancel the gravitational component of the driving stress for the backthrust

interpreting avulsion process from ancient alluvial sequences guadalope matarranya system northern spain and wasatch formation western colorado alluvial deposits of the guadalope matarranya system oligocene ebro basin spain and the wasatch formation eocene western colorado provide time integrated records of the process of river channel avulsion these sequences consist of isolated channel belt sandstones incised into and abruptly overlain by flood plain siltstones indicating deposition by avulsive river systems the geometry and distribution of channel incisions suggest that avulsion was not controlled by tectonics climate or base level changes but formed by autocyclic processes measurements from 221 channel fills in the guadalope matarranya system and 38 from the wasatch formation allow us to statistically characterize channel geometries we infer to be associated with establishment and abandonment of individual river avulsions paleoflow depths in both systems average 1 4 to 1 6 m aggradation height superelevation of channel margin levees are on average 0 6 and 1 1 times paleoflow depth in the guadalope matarranya and wasatch systems respectively these results are consistent with values from recently avulsed modern rivers and suggest that 1 flow depth is the appropriate parameter against which to scale the critical superelevation necessary for channel avulsion and 2 the increase in potential energy due to channel perching drives the lateral instability that is needed for avulsion to be successful numerous stacked channel fills indicate repeated reoccupation of the same site by avulsing channels these reoccupation channels indicate that inherited flood plain topography here abandoned channel forms was an important control on the arrival site of newly avulsed channels comparison of our results to others suggests two end member types of avulsion can take place incisional avulsion seen here is characterized by an early incision phase followed by infilling by migrating bar forms aggradational avulsion begins with aggradation followed in time by stream integration into a single downcutting channel we suggest that the type of avulsion is strongly influenced by whether or not the adjacent flood plain is well or poorly drained in both cases subsequent aggradation and channel perching increase the chances that some triggering event will lead to avulsion

coupling hydrus 1d code with geoelectrical measurements to investigate the infiltration process in the soil passage in the western part of damascus syria the daily climate data of two climate stations in the western part of damascus were used to calculate the local potential evapotranspiration the calculated evapotranspiration together with the precipitation and the saturated hydraulic conductivity of the soil was processed in hydrus 1d to simulate the infiltration process through the soil passage the simulation shows that the bottom flux has a maximum value of 2e 2 cm day while the soil water storage has a value of 30 cm furthermore four geoelectrical profiles were measured in 2011 to estimate the water content in the soil profile and to investigate the subsurface the measurements revealed the existence of two distinguishable layers the overlying agricultural soil of up to 3 4 m and an underlying clay horizon of up to more than 25 m thickness a comparison with lithological profiles from boreholes confirms the results of the geoelectrical measurements the water content of the first layer was estimated and the results show a saturation degree of 40 which represents retained water mainly originating from irrigation the existence of the clay layer is proof for confining conditions in the aquifer in this part of the area and that recharge does not take place through infiltration from surface

log boats wooden structures peat and palaeochannels the challenges and opportunities afforded by decadal monitoring of an active quarry a case study from shardlow quarry middle trent valley uk abstract the river trent uk is renowned for a rich palimpsest of alluvial archaeological remains buried within the holocene sands and gravels of the valley floor since the late 1990 s extraction of these postglacial deposits at shardlow quarry in the middle reach of the valley close to the confluence of the river trent and river derwent has been investigated and monitored on a weekly basis by a project team including geoarchaeologists such monitoring of large exposures of floodplain sand and gravel and adjacent pleistocene terrace deposits initially by volunteer activity but latterly funded by the aggregate company under a formal planning agreement has revealed significant alluvial archaeological remains including two logboats a possible brushwood platform several fish weirs and organic rich palaeochannel deposits this paper provides a summary of the wealth of this resource but also reflects on the challenges of undertaking geoarchaeological studies in complex alluvial environments over such an extended time period it concludes by providing advice for best practice that could be applied to other long term studies within similar environments

mineralogy petrography and whole rock geochemistry of the tertiary granitic intrusions in the eastern pontides turkey abstract granitic intrusions in eocene and post eocene volcanic rocks outcrop in the northern and southern zones of the eastern pontides ne turkey intrusions in the northern zone extend nw se whereas those in the southern zone are nearly e w orientated the contacts of the intrusions with the volcanic rocks are sharp epidotized and include volcanic xenoliths the margins of southern zone intrusions often contain abundant angular mafic microgranular enclaves of diorite to quartz diorite composition the rocks also show evidence of mingling and mixing between coeval mafic and felsic magmas field observations suggest a stopping type of ascent and emplacement style for the intrusions petrographically intrusions show variations in both colour and mineralogy with fine to medium granular monzonitic poikilitic rapakivi anti rapakivi and graphic textures based on modal mineralogy the northern rocks are monzonite quartz monzonite monzodiorite and quartz monzodiorite whereas the southern samples are monzogranite and granodiorite the rocks are generally calc alkaline to mildly alkaline transitional and metaluminous and show a cafemic trend the northern zone intrusions form a post collisional a type alkaline monzonitic association and southern zone intrusions form a post collisional i type granodioritic calc alkaline transitional association whole rock compositional data indicate that differentiation occurred via fractional crystallisation with or without magma mixing incompatible and rare earth element patterns indicate that both the northern and the southern zone intrusions were derived from melting of a mantle region enriched by subduction related fluids but evolved differently during ascent and emplacement u pb zircon dating in the southern zone yields an intrusion age of 44 4 0 3 ma regional geodynamics indicates post collisional extensional tectonics in the region crustal involvement and the level of emplacement may have been important for magmatic evolution especially for the southern zone intrusions after the cessation of subduction and subsequent crustal thickening

holocene climate variability as reflected by mid european lake level fluctuations and its probable impact on prehistoric human settlements abstract a data set of 180 radiocarbon tree ring and archaeological dates obtained from sediment sequences of 26 lakes in the jura mountains the northern french pre alps and the swiss plateau was used to construct a holocene mid european lake level record the dates do not indicate a random distribution over the holocene but form clusters suggesting an alternation of lower and higher climatically driven lake level phases they provide evidence of a rather unstable holocene climate punctuated by 15 phases of higher lake level 11 250 11 050 10 300 10 000 9550 9150 8300 8050 7550 7250 6350 5900 5650 5200 4850 4800 4150 3950 3500 3100 2750 2350 1800 1700 1300 1100 750 650 cal bp and after 1394 ad a comparison of this mid european lake level record with the gisp2 polar circulation index pci record the north atlantic ice rafting debris ird events and the 14 c record suggests teleconnections in a complex cryosphere ocean atmosphere system correlations between the gisp2 pci the mid european lake level the north atlantic ird and the residual 14 c records suggest that changes in the solar activity played a major role in holocene climate oscillations over the north atlantic area

post collisional plutonism with adakite like signatures the eocene saraycik granodiorite eastern pontides turkey the post collisional saraycik granodiorite intruded into a late paleocene to early eocene nappe pile that formed during collision of the pontides in the north and the anatolide tauride platform in the south leading to the formation of the izmir ankara erzincan suture a relatively shallow pluton intrusion depth 5 to 8 km was estimated from al in hornblende geobarometry and contact metamorphic assemblages the emplacement age is tightly constrained to 52 ma by two ar ar plateau and total fusion ages on biotite the main mass of the pluton consists of metaluminous to peraluminous biotite granodiorite and hornblende biotite granodiorite in addition up to 10 m thick dacitic and 25 cm thick aplitic dikes occur granodiorites and dacites show many close compositional similarities to high silica adakites from supra subduction zone settings but tend to be slightly more felsic and to have a higher aluminium saturation index chondrite normalized cn rare earth element patterns are characterized by high ratios of la yb cn concave upward shapes of the hree and a lack of significant eu anomalies in conjunction with relatively high abundances of ba and sr as well as low abundances of y hree and sc these patterns suggest a feldspar poor garnet amphibole rich fractionating mineral assemblage residue all samples have very similar nd sr isotopic characteristics regardless of rock type initial end values range from 0 3 to 1 2 and initial 87sr 86sr ratios from 0 70491 to 0 70529 it is suggested that the magmas formed by partial melting of mafic lower crust at elevated pressures 1 to 2 gpa

geodynamic significance of granitoid magmatism in the southeast anatolian orogen geochemical and geochronogical evidence from goksun afsin kahramanmaras turkey region in southeast anatolia there are number of tectonomagmatic units in the kahramanmaras malatya elazig region that are important in understanding the geological evolution of the southeast anatolian orogenic belt during the late cretaceous these are a metamorphic massifs b ophiolites c ophiolite related metamorphics and d granitoids the granitoids i e goksun afsin in kahramanmaras dogansehir in malatya and baskil in elazig intrude all the former units in a ne sw trending direction the granitoid in goksun afsin kahramanmaras region is mainly composed of granodioritic and granitic in composition the granodiorite contains a number of amphibole bearing mafic microgranular enclaves of different sizes whereas the granite is intruded by numerous aplitic dikes the granitoid rocks have typical calcalkaline geochemical features the ree and ocean ridge granite normalized multi element patterns and tectonomagmatic discrimination diagrams as well as biotite geochemistry suggest that the granitoids were formed in a volcanic arc setting the k ar geochronology of the granitoid rocks yielded ages ranging from 85 76 3 17 to 77 49 1 91 ma the field geochemical and geochronological data suggest the following late cretaceous tectonomagmatic scenario for southeast anatolia the ophiolites were formed in a suprasubduction zone tectonic setting whereas the ophiolite related metamorphic rocks formed either during the initiation of intraoceanic subduction or late thrusting 90 ma these units were then overthrust by the malatya keban platform during the progressive elimination of the southern neotethys thrusting of the malatya keban platform over the ophiolites and related metamorphic rocks was followed by the intrusion of the granitoids 88 85 ma along the tauride active continental margin in the southern neotethys

cenozoic evolution of the eastern black sea a test of depth dependent stretching models abstract subsidence analysis of the eastern black sea basin suggests that the stratigraphy of this deep extensional basin can be explained by a predominantly pure shear stretching history a strain rate inversion method that assumes pure shear extension obtains good fits between observed and predicted stratigraphy a relatively pure shear strain distribution is also obtained when a strain rate inversion algorithm is applied that allows extension to vary with depth without assuming its existence or form the timing of opening of the eastern black sea which occupied a back arc position during the closure of the tethys ocean has also been a subject of intense debate competing theories called for basin opening during the jurassic cretaceous or paleocene eocene our work suggests that extension likely continued into the early cenozoic in agreement with stratigraphic relationships onshore and with estimates for the timing of arc magmatism further basin deepening also appears to have occurred in the last 20 myr this anomalous subsidence event is focused in the northern part of the basin and reaches its peak at 15 10 ma we suggest that this comparatively localized shortening is associated with the northward movement of the arabian plate we also explore the effects of paleowater depth and elastic thickness on the results these parameters are controversial particularly for deep water basins and margins but their estimation is a necessary step in any analysis of the tectonic subsidence record stored in stratigraphy

mineral chemical investigation on sulfide mineralization of the istala deposit gumushane ne turkey abstract the mineralogy of the istala deposit gumushane northeastern turkey was studied in detail and a geochemical investigation was carried out using electron probe micro analysis epma sphalerite galena chalcopyrite and pyrite are the major sulfide minerals found in the istala deposit with minor amounts of bornite idaite tetrahedrite tennantite anilite yarrowite mckinstryite covellite and chalcocite in addition to these barite and a small quantity of quartz occur as gangue minerals based on the textural relations and mineral assemblages five different stages of crystallization have been recognized mineral paragenesis of the first four stages has been found to be similar whereas clear enrichment has been observed in the modal abundance of the copper sulfide mineral assemblage at the fifth stage ore formation whole rock geochemical analyses of the istala ore show an enrichment of ag content up to 3328 ppm optical observations and epma study indicated that abundant silver mineralization was found in the istala ore especially during the later stage ore deposition repetition to the presence of native silver in the samples a significant amount of silver was incorporated in bornite idaite tetrahedrite tennantite anilite yarrowite mckinstryite covellite and chalcocite whereas a trace amount of silver has been detected in sphalerite galena chalcopyrite and pyrite the homogenization temperatures th of the primary fluid inclusions were measured between 98 and 284 c with frequency peaks around 140 c 190 c and 240 c all data obtained support the theory that later stage copper rich sulfides formed under the low temperature conditions are responsible for the large amounts of silver content in the istala mine

a type granitoids from the eastern pontides ne turkey records for generation of hybrid a type rocks in a subduction related environment the eastern pontides is characterized by the many of intrusive bodies formed throughout the late mesozoic early cenozoic most of these are i type granitoids but here we present for the first time an a type pluton from the region to assess source characteristics and geodynamic implications the a type pirnalli pluton has a shrimp zircon u pb age of 81 2 1 ma it is composed of granite syenite and quartz monzonite and its enclaves are monzonitic in composition with elevated ga al ratios and low mg 42 the pluton is dominantly metaluminous a cnk 0 88 to 1 00 and belong to shoshonitic and ultra potassic series the samples are highly enriched in lree and show significant negative eu eu eu 0 33 to 0 92 ba nb sr and ti anomalies in the spidergrams the host rocks and their enclaves posses quite similar sr nd isotopic compositions isr 0 70693 to 0 70736 end 81 ma 2 6 to 2 0 tdm 0 94 to 1 12 ga pointing to a lower crustal parental magma with a minor contribution of lithospheric mantle we hypothesize that upwelling of asthenosphere triggered melting of chemically enriched upper mantle and basic magma formed melting of lower crust was provided by the underplating of this basic magma mixing between lower crust and mantle derived melts at depths of lower crust appears to be most reasonable petrogenetic process responsible for generation of the pluton sr nd isotope modeling suggests mixing of 82 90 of the lower crustal derived melt with 10 18 of the mantle derived melt then the hybrid melt ascended to shallower crustal level and underwent a limited fractionation process to generate a variety of rock types our data also suggest that the a type pirnalli pluton likely formed at an extensional environment of active continental margin throughout the late cretaceous ongoing extension then led to opening of black sea as a back arc basin further north of the eastern pontides

robust chronologies for landform development obtaining chronological control for geomorphological sequences can be problematic due to the fragmentary and non sequential nature of sediment and landform archives the robust analysis of 14c ages is often critical for the interpretation of these complicated sequences this paper demonstrates a robust methodology for the 14c dating of geomorphological sequences using a case study from the lower ribble valley northwest england the approach adopted incorporates using greater numbers of ages targeting plant macrofossils obtaining replicate measurements from single horizons to assess the extent of reworking and the use of bayesian approaches to test models of the relative order of events the extent of reworking of organic materials and space time dynamics of fluvial change means that it is critical that chronological control is sufficiently resourced with 14c measurements as a result bayesian approaches are increasingly important for the evaluation of large data sets assessing the conformability of relative order models informed by interpretation of the geomorphology can identify contexts or materials that are out of sequence and focuses attention on problem materials reworking and errors in interpretation outlier ages these relative order models provide a framework for the interrogation of sequences and a means for securing probability based age estimates for events that occur between dated contexts this approach has potential value in constraining the sequence of geomorphological development at scales that vary from individual sites to a catchment or region furthering understanding of forcing and change in geomorphological systems copyright 2008 john wiley sons ltd

bifurcation dynamics and avulsion duration in meandering rivers by one dimensional and three dimensional models at river bifurcations water and sediment are divided over two branches the dynamics of the bifurcation determine the long term evolution centuries of the downstream branches potentially leading to avulsion but the dynamics are poorly understood the long term evolution can only be studied by one dimensional models because of computational costs for such models a relation describing the sediment division is necessary but only few relations are available and these remain poorly tested so far we study the division of sediment and the morphodynamics on a timescale of decades to centuries by idealized three dimensional modeling of bifurcations with upstream meanders and dominantly bed load transport an upstream meander favors one bifurcate with more sediment and the other with more water leading to destabilization the bifurcations commonly attain a highly asymmetrical division of discharge and sediment after a few decades to a few centuries depending on combinations of the relevant parameters although past work on avulsions focused on slope advantage we found that bifurcations can be quasibalanced by opposing factors such as a bifurcate connected to the inner bend with a downstream slope advantage nearly balanced bifurcations develop much slower than unbalanced bifurcations which explains the observed variation in avulsion duration in natural systems which branch becomes dominant and the timescale to attain model equilibrium are determined by the length of the downstream bifurcates the radius of the upstream bend a possible gradient advantage for one bifurcate and notably the width depth ratio the latter determines the character of the bars which may result in overdeepening and unstable bars the distance between the beginning of the upstream bend and the bifurcation determines the location of such bars and pools which may switch the dominant bifurcate in fact when the bifurcation is quasibalanced by opposing factors any minor disturbance or a different choice of roughness or sediment transport predictor may switch the dominant bifurcate the division of sediment is nearly the same as the division of flow discharge in most runs until the discharge division becomes very asymmetrical so that a bifurcate does not close off entirely this partly explains the sustained existence of residual channels and existence of anastomosing rivers and the potential for reoccupation of old channel courses we develop a new relation for sediment division at bifurcations in one dimensional models incorporating the effect of meandering the flow and sediment divisions predicted by two existing relations and the new relation for one dimensional models are in qualitative agreement with the three dimensional model these one dimensional relations are however of limited value for wider rivers because they lack the highly three dimensional bar dynamics that may switch the direction of bifurcation evolution the potential effects of bed sediment sorting bank erosion and levee formation on bifurcation stability and avulsion duration are discussed

slow senonian and fast palaeocene early eocene uplift of the granitoids in the central eastern pontides turkey apatite fission track results abstract dating and forward modelling of the fission track data of apatite samples from the dereli ebinkarahisar region south of giresun in the eastern turkish pontides provides quantitative data on the regional tectonics resulting from the closure of neo thetys and the collision of eurasia and gondwana the age vs elevation profiles identified senonian 80 7 3 2 to 62 4 2 5 ma slow uplift and denudation interpreted as the result of the diapiric ascent of subduction related plutons above the neo tethyan subduction zone beneath the eurasian continent this was followed by rapid differential uplift during the palaeocene early eocene 57 4 2 4 to 47 8 2 4 ma which juxtaposed granitoid units of different ages compositions and emplacement levels in the crust and is thought to be related to the collision between the pontide eurasian and anatolide gondwana basements the modelling results must be interpreted with caution but appear to indicate a period of mio pliocene ca 5 ma reheating related to volcanism associated with the westward escape of the anatolian plate and uplift from the pliocene ca 3 5 ma up to the present

quaternary river terraces in england forms sediments and processes abstract flights of quaternary river terraces in south and east england have common characteristics involving low gradient planed or irregular bedrock surfaces and single or multi storey gravel deposits rather than depending on warm cold or cold warm transitions it is suggested that bedrock planation working depths of gravel and later stage relatively shallow aggradations are all dominantly of cold climate origin basal sediments show active incorporation of plucked and periglacially shattered materials whilst super incumbent units incorporating up catchment and slope derived materials demonstrate later cold stage sediment influx and consequent cessation of active bedrock erosion channel activity effecting both planation and deposition are reviewed together with the detailed sedimentology of gravelly sediments which show evidence of both autogenic processes bar migration channel switching and infilling and truncation of upper sedimentation units cold climate indicators turbation ice wedge casts and frozen block transport and specifically for the last glacial interglacial cycle varying sediment flux as climates changed both interglacial and transitional activities are believed to be of lesser morphological significance whilst prior uplift is taken as enabling rather than being a generator of terrace within the timescale of a glacial interglacial cycle variations within cold stage climates varying sediment influx and channel belt bedrock erosion are stressed as dominating mid catchment and mid latitude quaternary terracing at the glacial interglacial scale

alteration mineralogy lithochemistry and stable isotope geochemistry of the murgul artvin ne turkey volcanic hosted massive sulfide deposit implications for the alteration age and ore forming fluids abstract the murgul artvin ne turkey massive sulfide deposit is hosted dominantly by late cretaceous calc alkaline to transitional felsic volcanics the footwall rocks are represented by dacitic flows and pyroclastics whereas the hanging wall rocks consist of epiclastic rocks chemical exhalative rocks gypsum bearing vitric tuff purple vitric tuff and dacitic flows multi element variation diagrams of the hanging wall and footwall rocks exhibit similar patterns with considerable enrichment in k rb and ba and depletion in nb sr ti and p the chondrite normalized rare earth element rees patterns of all the rocks are characterized by pronounced positive negative eu anomalies as a result of different degrees of hydrothermal alteration and the semi protected effects of plagioclase fractionation mineralogical results suggest illite illite smectite chlorite kaolinite and chlorite in the footwall rocks and illite smectite kaolinite and chlorite illite in the hanging wall rocks overall the alteration pattern is represented by silica sericite chlorite and chlorite carbonate epidote sericite and quartz albite zones increments of ishikawa alteration indexes resulting from gains in k 2 o and losses in na 2 o and the chlorite carbonate pyrite index towards to the center of the stringer zone indicate the inner parts of the alteration zones calculations of the changes in the chemical mass imply a general volume increase in the footwall rocks abnormal volume increases are explained by silica and iron enrichments and a total depletion of alkalis in silica zone relative k increments are linked to the sericitization of plagioclase and glass shards and the formation of illite smectite in the sericite zone in addition fe enrichment is always met by pyrite formation accompanied by quartz and chlorite illite is favored over chlorite smectite and kaolinite in the central part of the ore body due to the increase in the al k na ca ratio although the rees were enriched in the silicification zone light rees show depletion in the silicification zone and enrichment in the other zones in contrast to the heavy rees behavior hydrothermal alteration within the hanging wall rocks apart from the gypsum bearing vitric tuffs is primarily controlled by chloritization with proportional fe and mg enrichments and sericitization the 18 o and d values of clay minerals systematically change with increasing formation temperature from 6 6 to 8 7 and 42 to 50 for illites and 8 6 and 52 for chlorite respectively the o and h stable isotopic data imply that hydrothermal alteration processes occurred at 253 332 c for illites and 136 c for chlorite with a temperature decrease outward from the center of the deposit the positive 34 s values 20 3 to 20 4 for gypsum suggest contributions from seawater sulfate reduced by fe oxide hydroxide phases within altered volcanic units thus the hydrothermal alteration possibly formed via a dissolution precipitation mechanism that operated under acidic conditions the k ar dating 73 62 ma of the illites indicates an illitization process from the maastrichtian to early danian period

geoarchaeological records in temperate european river valleys quantifying the resource assessing its potential and managing its future throughout the quaternary episodes of glaciation and associated low sea level have resulted in the connection of the terrestrial landmasses of britain and mainland europe the river systems that established themselves across these newly emergent land surfaces of the coastal plain would have created important migration corridors for both animals and humans a point corroborated by the affinity of palaeolithic remains across britain and europe technological developments within the last decade have allowed these now submerged valley floors and adjacent terrestrial landscapes associated with the last cold stage and early and middle parts of the current holocene interglacial to be explored and their archaeological legacies unravelled providing geoarchaeologists with an opportunity to contribute to major cultural debates however in order to maximize knowledge it is essential that geoarchaeologists working within river valleys across both britain and the european continent are addressing similar research questions by collecting data using comparable methodologies this paper reviews the approach taken in different regions and provides a baseline assessment to allow the development of a coherent european wide framework for alluvial geoarchaeology and geoprospection particularly with respect to the holocene record

quantitative metrics that describe river deltas and their channel networks 1 densely populated river deltas are losing land at an alarming rate and to successfully restore these environments we must understand the details of their morphology toward this end we present a set of five metrics that describe delta morphology 1 the fractal dimension 2 the distribution of island sizes 3 the nearest edge distance 4 a synthetic distribution of sediment fluxes at the shoreline and 5 the nourishment area the nearest edge distance is the shortest distance to channelized or unchannelized water from a given location on the delta and is analogous to the inverse of drainage density in tributary networks the nourishment area is the downstream delta area supplied by the sediment coming through a given channel cross section and is analogous to catchment area in tributary networks as a first step we apply these metrics to four relatively simple fluvially dominated delta networks for all these deltas the average nearest edge distances are remarkably constant moving down delta suggesting that the network organizes itself to maintain a consistent distance to the nearest channel nourishment area distributions can be predicted from a river mouth bar model of delta growth and also scale with the width of the channel and with the length of the longest channel analogous to hack s law for drainage basins the four delta channel networks are fractal but power laws and scale invariance appear to be less pervasive than in tributary networks thus deltas may occupy an advantageous middle ground between complete similarity and complete dissimilarity where morphologic differences indicate different behavior

late pleistocene holocene river dynamics at the trent soar confluence england uk although river confluences have received geomorphic attention in recent years it is difficult to upscale these studies so confluence dominated reaches are commonly presumed to be either 1 braided or 2 meandering and characterized by laterally migrating channels if the geomorphology of a confluence zone is to be considered over longer timescales changes in river style need to be taken into account this paper uses a combination of remote sensing techniques lidar gpr er borehole survey and chronometric dating to test this differentiation in the confluence zone of a medium sized mixed load temperate river system trent uk which on the basis of planform evidence appears to conform to the meandering model however the analysis of confluence sediment body stratigraphy demonstrates that the confluence does not correspond with a simple meander migration model and chronostratigraphic data suggests it has undergone two major transformations firstly from a high energy braid plain confluence in the lateglacial 25 13 k yrs cal bp to a lower energy braided confluence in the early to middle holocene early holocene 2 4 kyr bp which created a compound terrace second incision into this terrace creating a single channel confluence 2 4 0 5 kyr cal bp with a high sinuosity south bank tributary the river soar the confluence sediment body stratigraphy is characterized by a basal suite of late pleistocene gravels bisected by younger channel fills which grade into the intervening levee and overbank sediments the best explanation for the confluence sediment body stratigraphy encountered is that frequent switching soft avulsions sensu edmonds et al 2011 of the tributary are responsible for the downstream movement of the channel confluence at an average rate of approximately 0 5 m per year dissecting and reworking older braid plain sediments the late holocene evolution of the confluence can be seen as a variant of the incisional frequent channel reorganization avulsion model with sequential downstream migration of the reattachment point copyright 2012 john wiley sons ltd

adakite like granitoid porphyries in the eastern pontides ne turkey potential parental melts and geodynamic implications abstract the tectonic setting of the eastern pontides during the late mesozoic to early cenozoic remains a subject of debate petrogenesis of adakite like granitoid porphyries plays a critical role in determining the nature of the lower continental crust and mantle dynamics during orogenic processes in the region here we describe for the first time the late paleocene to early eocene adakite like granitoid porphyries from the northern part of the eastern pontides although their counterparts in the southern part have recently been found the adakitic porphyries which emplaced into the subduction related turonian santonian volcanics from northern part of the region consist of i type calc alkaline quartz monzonite tonalite sio2 62 89 65 07 wt and high k calc alkaline granodiorite granite associations sio2 69 06 70 43 wt the former displays peraluminous to metaluminous signatures whereas the latter shows peraluminous geochemical character the granite granodiorite porphyries have high k2o 3 32 3 84 wt and low na2o 3 48 4 61 wt and mgo 0 91 1 04 wt relative to the quartz monzonite tonalite association k2o 1 50 1 92 wt na2o 4 08 6 45 wt mgo 1 44 2 07 wt ar ar geochronology studies on the amphibole separates reveal that the adakite like porphyries have a crystallization ages of 51 34 0 27 to 53 55 0 34 ma here we contend that these rocks were formed by partial fusion of a mafic lower continental crust in a collisional phase but not in a subduction setting all the samples exhibit the typical geochemical characteristics of adakite that is high sr 250 1141 ppm high sr y ratios 16 147 low y 6 8 14 8 ppm and low hree concentrations they are similar to adakites formed by slab melting associated with the subduction zone however the rocks exhibit heterogeneity in isotopic composition with isr ranging from 0 70554 to 0 70986 end 51 ma from 8 5 to 0 9 and nd model ages from 0 72 to 1 26 ga the samples are characterized by relatively high th th u and no significant eu anomalies implying that garnet was stable in their source during partial melting the compositional diversity between rock groups is probably related to partial melting of heterogeneous lower crustal source all of the features are inconsistent with a slab melting origin and slab related petrogenetic model but instead they favor an origin by melting of heterogeneous lower continental crust due to a thermal anomaly that was induced by the upwelling of the asthenosphere through a slab break off in a collisional setting these interpretations argue against the evidence for the presence of an early cenozoic arc setting in the eastern pontides instead the early cenozoic time in the region may be attributed to a geodynamic response to a post collisional uplift phase that occurred along the continent continent collision between the pontide and the anatolide tauride blocks

evolution of a bifurcation in a meandering river with adjustable channel widths rhine delta apex the netherlands rivers may dramatically change course on a fluvial plain such an avulsion temporarily leads to two active channels connected at a bifurcation here we study the effect of dynamic meandering at the bifurcation and the effect of channel width adjustment to changing discharge in both downstream branches on the evolution of a bifurcation and coexisting channels as an example we reconstructed the last major avulsion at the rhine delta apex we combined historical and geological data to reconstruct a slowly developing avulsion process spanning 2000 years and involving channel width adjustment and meandering at the bifurcation based on earlier idealised models we developed a one dimensional model for long term morphodynamic prediction of upstream channel and bifurcates connected at the bifurcation node the model predicts flow and sediment partitioning at the node including the effect of migrating meanders at the bifurcation and channel width adjustment bifurcate channel width adaptation to changing discharge partitioning dramatically slows the pacing of bifurcation evolution because the sediment balance for width adjustment and bed evolution are coupled the model further shows that meandering at the bifurcation modulates channel abandonment or enlargement periodically this explains hitherto unrecognised reactivation signals in the sedimentary record of the studied bifurcation meander belts newly identified in our geological reconstruction historical maps show that bifurcation migration due to meander bend dynamics increases the bifurcation angle which increases the rate of closure of one bifurcate the combination of model and reconstruction identifies the relevant timescales for bifurcation evolution and avulsion duration these are the time required to fill one downstream channel over one backwater length the time to translate one meander wavelength downstream and for strong river banks the adaptation timescale to adjust channel width the findings have relevance for all avulsions where channel width can adjust to changing discharge and where meandering occurs copyright 2011 john wiley sons ltd

petrology and geochemistry of tertiary volcanic rocks from the ikizce ordu area ne turkey implications for the evolution of the eastern pontide paleo magmatic arc abstract tertiary volcanism in the ikizce region at the western edge of the eastern pontides paleo magmatic arc is represented by basaltic and andesitic rocks associated with sediments deposited in a shallow basin environment the basaltic rocks contain plagioclase an58 80 olivine fo82 84 clinopyroxene wo44 48en35 42fs7 17 hornblende mg 0 68 0 76 phenocrysts and magnetite microcrysts whereas the andesitic rocks include plagioclase an25 61 clinopyroxene wo46 49en38 43fs11 13 hornblende mg 0 48 0 81 biotite mg 0 48 0 60 phenocrysts titanomagnetite apatite and zircon microcrysts geochemical data indicate magmatic evolution from tholeiitic alkaline transitional to calc alkaline characteristics with medium k contents the geochemical variation in the rocks can be explained by fractionation of common mineral phases such as clinopyroxene olivine hornblende plagioclase magnetite and apatite the trace elements distributions of the volcanic rocks show similarities to those of e type morb have a shape that is typical of rocks from subduction related tectonic setting with enrichment in lile and to a lesser extent in lree but depletion in hfse the rocks evolved from a parental magma derived from an enriched source formed by subduction induced metasomatism of basaltic rocks the latter formed through clinopyroxene olivine controlled fractionation in a high level magma chamber the andesitic rocks developed through hornblende plagioclase controlled fractionation in shallow level magma chamber s

from sedimentary records to sediment budgets multiple approaches to catchment sediment flux this paper reviews the traditional approach to sediment budget studies in geomorphology new approaches and more specifically the potential impact of new methodological advances each component of the budget is discussed including the spatial and volumetric estimations of erosion deposition and storage and the precision and accuracy of flux rate estimation examples are used from recent work in germany the netherlands and the uk and include the pedogenic approach to erosion estimation remote sensing lidar geophysics and sediment based dating techniques for flux rate estimation the precision and accuracy of catchment sediment flux estimates based upon sediment storage is not only dependant upon volumetric accuracy but also on the precision and accuracy of sediment dating in this area there has been a revolution with direct sediment dating techniques tl osl esr freeing budget studies from the constraints and biases of radiocarbon of particular importance is the use of cosmogenic nuclides for dating but which can also be used to derive long term erosion rates but only using a steady state assumption finally a tentative initial application of the sediment budget approach to pleistocene terrace staircase in unglaciated basins is discussed it is argued that only now do we have the techniques available to be able to produce accurate sediment budget estimations at spatial scales greater than that of zero order basins and over time periods greater than that covered by direct observations

petrochemistry and petrology of i type granitoids in an arc setting the composite torul pluton eastern pontides ne turkey the upper cretaceous torul pluton located in the eastern pontides is of sub alkaline affinity and displays features typical of volcanic arc granitoids it is a composite pluton consisting of granodiorite biotite hornblende monzogranite quartz monzodiorite quartz monzonite and hornblende biotite monzogranite the oldest syenogranite 77 9 0 3 ma and the youngest quartz diorite form small stocks within the pluton samples from the granodiorites biotite hornblende monzogranites quartz monzodiorites quartz monzonites and hornblende biotite monzogranites have sio2 between 57 and 68 wt and display high k calc alkaline metaluminous to peraluminous characteristics chondrite normalized ree patterns are fractionated lacn lucn 6 0 14 2 with pronounced negative eu anomalies eu eu 0 59 0 84 initial nd i values vary between 3 1 and 4 1 initial 87sr 86sr values between 0 7058 and 0 7072 and 18o values between 4 4 and 7 3 the quartz diorites are characterized by relatively high mg number of 36 38 low contents of na2o 2 3 2 5 wt and sio2 52 55 wt and medium k calc alkaline metaluminous composition chondrite normalized ree patterns are relatively flat la yb cn 2 8 3 3 tb yb cn 1 2 and show small negative eu anomalies eu eu 0 74 0 76 compared to the other rock types radiogenic isotope signatures of the quartz diorites show higher 87sr 86sr 0 7075 0 7079 and lower nd i 4 5 to 5 3 the syenogranites have high sio2 70 74 wt and display high k calc alkaline peraluminous characteristics their ree patterns are characterized by higher lacn lucn 12 9 and eu eu 0 76 0 77 values compared to the quartz diorites isotopic signatures of these rocks nd i 4 0 to 3 3 87sr 86sr i 0 7034 0 7060 18 o 4 9 to 8 2 are largely similar to the other rock types but differ from that of the quartz diorites fractionation of plagioclase hornblende pyroxene and fe ti oxides played an important role in the evolution of torul granitoids the crystallization temperatures of the melts ranged from 800 to 900 c as determined from zircon and apatite saturation thermometry all these characteristics combined with low k2o na2o low al2o3 feot mgo tio2 and low na2o k2o feot mgo tio2 ratios suggest an origin through dehydration melting of mafic lower crustal source rocks

changes in solar activity and holocene climatic shifts derived from 14c wiggle match dated peat deposits closely spaced sequences of accelerator mass spectrometer ams 14 c dates of peat deposits display century scale wiggles which can be e tted to the radiocarbon calibration curve by wiggle matching such sequences high precision calendar age chronologiescan be generated which show that changes in mire surface wetness during the bronze age iron age transition c 850 cal bc and the little ice age wolf sporer maunder and dalton minima occurred during periods of suddenly increasing atmospheric concentration of 14 c replicate evidence from peat based proxy climate indicators in northwest europe suggest these changes in climate may have been driven by temporary declines of solar activity carbon accumulation rates of two raised peat bogs in the uk and denmark record low values during the little ice age which ree ects reduced primary productivity of the peat forming vegetation during these periods of climatic deterioration

large scale structure of calamus river deposits nebraska usa revealed using ground penetrating radar the large scale i e bar scale structure of channel deposits of the braided low sinuosity calamus river nebraska is described using ground penetrating radar gpr profiles combined with vibracores basal erosion surfaces are generally overlain by medium scale trough cross stratified sets 3 25 cm thick very coarse to medium sands that are associated with relatively high amplitude discontinuous gpr reflectors overlying deposits are bioturbated small scale cross stratified sets 3 cm thick and vegetation rich fine to very fine sands that are associated with low amplitude discontinuous reflectors near surface peat and turf have no associated gpr reflectors in along stream profiles through braid and point bars most gpr reflectors dip downstream at up to 2 relative to the basal erosion surface but some reflectors in the upstream parts of bars are parallel to the basal erosion surface or dip upstream in cross stream profiles through bars gpr reflectors are either approximately parallel to bar surfaces or have low angle inclinations up to 6 towards cut banks of adjacent curved channels basal erosion surfaces become deeper towards cut banks of curved channels these structures can be explained by lateral and downstream growth of bars combined with vertical accretion convex upwards forms up to 0 5 m high several metres across and tens of metres long represent episodic accretion of unit bars scroll bars and bar heads stratal patterns in channel fills record a complicated history of erosion and deposition during filling including migration of relatively small bars a revised facies model for this type of sandy braided river has been constructed based on this new information on large scale bedding structure

volcanic belts as markers of the mesozoic cenozoic active margin of eurasia abstract from the triassic to the present linear belts of calc alkaline volcanism developed along the southern margin of eurasia in the triassic the calc alkaline belt can be traced in turan fore caucasus crimea and dobrogea its development is related to the closure of the paleo tethys when fragments of gondwana iran afghanistan etc were approaching eurasia since the early jurassic calc alkaline volcanism has been related to subduction of the oceanic crust of the mesozoic tethys five stages of calc alkaline volcanic activity can be distinguished early jurassic middle jurassic early cretaceous late cretaceous paleogene and late miocene quaternary the configuration of the volcanic belts the intensity of the volcanism and the chemistry of the erupted products change considerably from stage to stage mesozoic belts were most pronounced in the pontian transcaucasian segment of the margin starting from the late cretaceous and especially in the cenozoic the volcanic belts can be continuously traced from the balkans to afghanistan most of the belts were actually island arcs formed on the fragments of the hercynian of baikalian basement and in this respect similar to the island arc of japan only the incipient island arcs of senonian age formed close to the passive margin of gondwana are the exceptions they were built on oceanic crust and are geochemically close to the mariana arc at certain times early jurassic eocene parallel chains of island arcs existed in general the situation resembled the present day convergent boundary in the western pacific as closure of the tethys proceeded island arcs gave way to marginal continental volcanic belts with wide spread development of high potassium particularly shoshonitic series peaks of volcanic activity in the bajocian late cretaceous eocene and late miocene present alternated with quiet periods and corresponded to the times when the convergence rate between africa and eurasia increased the opening of the back arc basins is reflected in outbursts of basaltic rift type volcanism these outbursts occurred in the toarcian aalenian bathonian late jurassic aptian turonian and early middle eocene

optical dating of holocene sediments from a variety of geomorphic settings using single grains of quartz this paper presents an improved method for the optical dating of holocene sediments from a variety of geomorphic settings we have measured the equivalent dose de in individual grains of quartz using green laser light for optical stimulation and have simulated the de distributions for multiple grain synthetic aliquots using the single grain data for 12 samples of known independent age we show that application of a minimum age model to the single grain and small 10 grain aliquot de data provides the most accurate estimate of the burial dose for nine of the samples examined 3 aeolian 5 fluvial and 1 marine the weighted mean de as obtained using the central age model gives rise to burial age overestimates of up to a factor of 10 for these nine samples whether single grains small aliquots or large 100 grain aliquots are used for the other three samples two aeolian and one fluvial application of either the minimum age model or the central age model to the single grain small aliquot and large aliquot de data yields burial ages in accord with the independent age control we infer that these three samples were well bleached at the time of deposition these results show that heterogeneous bleaching of the optical dating signal is commonplace in nature and that aeolian transport offers no guarantee that the sample will be well bleached at the time of deposition we also show that grains sensitive to infrared ir stimulation can give rise to low de values which will result in significant underestimation of the burial dose and hence of the age of deposition we demonstrate that use of a modified single aliquot regenerative dose protocol incorporating ir stimulation prior to green light stimulation deals effectively with contamination by ir sensitive grains we conclude that application of the modified protocol to single grains or small aliquots of quartz using the lowest de population to estimate the burial dose is the best means of obtaining reliable ages for holocene sediments from a wide range of depositional environments d 2003 elsevier b v all rights reserved

oxygen and sulfur isotope geochemistry revealing a significant crustal signature in the genesis of the post collisional granitoids in central anatolia turkey abstract late cretaceous granitoid rocks from central anatolia comprise s i a type plutons derived from the collisional stages of the neo tethyan convergence system in central turkey these granitoids intrude the tectonic imbrication zone consisting of blocks of supra subduction zone type ssz type central anatolian ophiolite and crustal metasediments which are present in the izmir ankara erzincan suture zone the plutons are overlain by late palaeocene early eocene or younger detrital sediments granitoid formation is thought to be related to magma generation processes occurring in a post collisional lithospheric detachment related geodynamic setting that resulted from slab break off or lithospheric delamination whole rock s and quartz feldspar o isotope data from these plutons yields a broad range of values and both parameters indicate a nearly exclusively supracrustal origin for the s type granites as well as a significant crustal contribution in the genesis of the hybrid i type and a type granitoids the more mafic i type and a type granitoid rocks of any given suite have lower s and o values indicative of their larger degree of mantle component the combined stable isotope geochemical compositions when coupled with major trace and ree geochemistry and regional geology provide evidence that the significant crustal contribution originated from a metasomatized mantle layer which was affected by earlier ssz derived fluids and then accreted into the subcontinental lithosphere as collision occurred the partial melting of such a metasomatized mantle layer in a post collisional extensional geodynamic setting supplied either by the slab break off or lithospheric delamination mechanisms provided the significant crustal signature in the hybrid magmas of the late cretaceous i type and a type granitoids in central anatolia turkey

k ar ages of granitoids unravel the stages of neo tethyan convergence in the eastern pontides and central anatolia turkey k ar dating of mineral separates extracted from various granitoid rock units of the eastern pontides and central anatolia turkey has provided some new insights unravelling various stages of the neo tethyan convergence system which evolved with northward subduction between the eurasian plate ep to the north and the tauride anatolide platform tap to the south along the izmir ankara erzincan suture iaes zone arc related granitoid rocks are only encountered in the eastern pontides and yield k ar cooling ages of both early cretaceous 138 5 2 2 ma early arc and late cretaceous ranging from 75 7 0 0 to 66 5 1 5 ma mature arc respectively the multi sourced granitoids of the eastern pontides with a predominant mantle component and k ar ages between 40 and 50 ma are considered to be a part of post collisional slab break off magmatism accompanied by tectonic denudation of pre late cretaceous granitoid rocks following juxtaposition of the ep and the tap around 55 50 ma in the eastern pontides the k ar cooling ages of collision related s i and a type granitoids in central anatolia reflect good synchronism between 80 and 65 ma suggesting a coeval genesis in a unique geodynamic setting but with derivation from various sources namely purely crustal purely mantle and or of mixed origin this sort of simultaneous generation model for these s i a type intrusives seems to be consistent with a post collisional lithospheric detachment related geodynamic setting i type granodioritic to tonalitic intrusives with k ar cooling ages ranging from 40 to 48 ma in east central anatolia are interpreted to have been derived from a post collisional within plate extension related geodynamic setting following the amalgamation of the ep and the tap in east central anatolia

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

the temporal evolution of the active margin along the southeast anatolian orogenic belt se turkey evidence from u pb ar ar and fission track chronology abstract the southeast anatolian orogenic belt saob resulted from the north dipping subduction of the southern neotethyan oceanic lithosphere in late mesozoic and early cenozoic however the timing and the rate of the continental collision are still under debate here we present new u pb ar ar and fission track ages from the i type calc alkaline granitoids esence dogansehir and baskil cutting the goksun ispendere and komurhan ophiolites and also the malatya keban metamorphics representing the tauride active continental margin along the saob in this study high to low temperature thermochronological methods applied to the granitoids are used to understand the temporal and geodynamic evolution of the tauride active continental margin and continental collision between tauride and arabian platforms in the frame of the neotethyan convergence during cretaceous and miocene the u pb zircon ages range from 83 to 88 ma for the baskil and from 81 to 83 ma for the esence granitoids the 39 ar 40 ar ages indicate that these late cretaceous granitoids cooled below 300 c in 6 10 ma the formation ages and the timing of the gradual cooling of the late cretaceous granitoids are similar to metamorphism age and the timing of the exhumation of the hp lt bitlis metamorphics during this stage the combined field geochemistry and geo thermochronological data suggest that the first continental collision event occurred between bitlis puturge micro continents to the south and tauride platform to the north in an oblique subduction zone between 84 and 74 ma the granitoids continued uplifting during early middle eocene together with the exhumation of hp uht berit metaophiolite in an extensional regime related to the opening of the maden back arc basin this period also let the intrusion of the dogansehir arc magmatism intruding the puturge and malatya keban metamorphics berit metaophiolite and maden complex the eocene dogansehir granitoid has similar u pb and 39 ar 40 ar ages suggesting a fast cooling the apatite fission track aft ages for all granitoid bodies suggest that they were mainly cooled or uplifted in two episodes where the first one is in the eocene in an extensional setting the aft data marked the final continental collision between the taurides and the arabian platform first in oligocene and the break off of the subducted slab and the delamination process caused fast uplift of the eastern anatolia during middle to late miocene

timing of neotectonic fracturing by fission track dating of obsidian in filling faults in the ikizdere rize area ne black sea region turkey there are several ne sw and nnw sse trending sets of neotectonic faults that are infilled with obsidians in the district of the ne black sea region turkey using the fission track technique it is estimated that these fracturefilling obsidians were formed between 1 73 0 10 and 1 93 0 15 ma this short period is consistent with a unique eruption and is supported by petrographic and geochemical data that reveal very homogenous characteristics although existing literature data indicate that these faults are part of the early pliocene neotectonic fracture system in this region the determination of latest pliocene pleistocene formation for the obsidians better constrains its timing

on the densities of etchable fission tracks in a mineral and co irradiated external detector with reference to fission track dating of minerals abstract the ratio r of the densities of etchable fission tracks in a mineral and co irradiated external detector is shown to depend on the length ratios of the latent l f l f and etched fission tracks l e l e in the two media calculations of l f for apatite titanite zircon and l f for muscovite external detectors allow a precise determination of r and confirm that neglecting r could constitute the most significant source of systematic error in fission track dating with the external detector method the ratios of the measured fission track densities in an external and internal surface of apatite and a muscovite external detector are calculated from r and the track counting efficiencies q the fact that the results are consistent with the experiment supports the accuracy of r and of the q factors the external detector ages of a basal and prismatic section of durango apatite are consistent with its reference age without the need for a length correction a critical examination of the uncertainties related to the thermal neutron fluence measurements fission decay constant calculated r value independently determined q factors and the reference age of the standard demonstrates that the assumption that a reduction of the confined track length of the spontaneous tracks in durango apatite necessitates a proportional correction of its apparent fission track age is the element most in question published u th he ages lend support to the conclusion that such a correction is not required the significance of r and of the ratio q of the q factors for the induced and spontaneous track counts leads us to propose a formalisation of the age equation in which these are included as well as a formal length correction l which is however not set equal to the ratio of the confined track lengths of the induced and spontaneous tracks the accuracy of the thermal neutron fluence and the decay constant leads us to propose a possible deconvolution of the calibration factor if for suitable age standards l 1 the proposed deconvoluted calibration factor 0 is a function of r and q which can be determined in ways that are independent of the reference ages of the standards this can either be interpreted as a multiple calibration or as establishing the fission track method as an independent dating method

gold in turkey a missing link in tethyan metallogeny abstract the gold metallogeny of turkey constitutes a sector of the tethyan eurasian metallogenic belt temb within the alpine himalayan orogenic system that formed from jurassic cretaceous to the present this orogenic system produced many different types of deposits related to subduction collision post collision and rifting processes gold deposits as well as other mineral deposits of turkey are mainly concentrated in late mesozoic and tertiary rocks evaluation of the gold metallogeny of turkey is based on a gis database compilation of known gold deposits and prospects currently available data show that turkey has a gold endowment including reserves and resources of approximately 31 5 m oz 979 tonnes in 51 deposits 21 of which contain more than 0 2 m oz gold the other 30 deposits contain a total of approximately 1 m oz 31 tonnes gold resources two recent discoveries kisladag and copler currently contain total resources of 17 6 m oz au 549 tonnes more than 50 of the total turkish gold endowment turkey possesses a wide spectrum of gold deposits related to mesozoic and cenozoic volcanoplutonic arcs however porphyry gold copper epithermal gold including both high and low sulfidation styles and gold rich volcanic associated massive sulfide including both kuroko and cyprus types are the most economically important to date orogenic gold including listwanite hosted placer gold and skarn hosted gold are relatively less important or abundant deposit types other potential gold systems for exploration include carlin type gold detachment fault related gold iron oxide copper gold and gold in carbonate replacement and manganese deposits

exchanges of sediment between the flood plain and channel of the amazon river in brazil sediment transport through the brazilian sector of the amazon river valley a distance of 2010 km involves exchanges between the channel and the flood plain that in each direction exceed the annual flux of sediment out of the river at obidos 1200 mt yr 1 the exchanges occur through bank erosion bar deposition settling from diffuse overbank flow and sedimentation in flood plain channels we estimated the magnitude of these exchanges for each of 10 reaches of the valley and combined them with calculations of sediment transport into and out of the reaches based on sediment sampling and flow records to define a sediment budget for each reach residuals in the sediment budget of a reach include errors of estimation and erosion or deposition within the channel the annual supply of sediment entering the channel from bank erosion was estimated to average 1570 mt yr 1 1 3 the obidos flux and the amount transferred from channel transport to the bars 380 mt yr 1 and the flood plain 460 mt yr 1 in channelized flow 1230 mt yr 1 in diffuse overbank flow totaled 2070 mt yr 1 1 7 the obidos flux thus deposition on the bars and flood plain exceeded bank erosion by 500 mt yr 1 over a 10 16 yr period sampling and calculation of sediment loads in the channel indicate a net accumulation in the valley floor of approximately 200 mt yr 1 over 16 yr crudely validating the process based calculations of the sediment budget which in turn illuminate the physical controls on each exchange process another 300 400 mt yr 1 are deposited in a delta plain downstream of obidos the components of the sediment budget reflect hydrologic characteristics of the valley floor and geomorphic characteristics of the channel and flood plain which in turn are influenced by tectonic features of the amazon structural trough

geochemistry fluid inclusion and stable isotope constraints c and o of the sivrikaya fe skarn mineralization rize ne turkey abstract the sivrikaya fe skarn mineralization is hosted by dolomitic limestone layers of late cretaceous volcano sedimentary unit comprised of andesite basalt and their pyroclastites including sandstone shale and dolomitic limestone layers intrusion of the late cretaceous eocene ikizdere granitoid in the volcano sedimentary unit resulted in skarn mineralization along the granitoid dolomitic limestone contact the ore is associated with exoskarns and mineralization is characterized by early anhydrous garnet and pyroxene with late hydrous minerals such as epidote tremolite actinolite and chlorite the ore minerals are mainly magnetite and hematite with minor amounts of pyrite and chalcopyrite the composition of garnet and pyroxene in the exoskarn is adr 79 45 99 03 grs 0 17 9 prs 0 97 2 65 and di 69 1 77 1 hd 22 2 29 8 jhn 0 6 1 4 respectively and abundances of magnetite in the ore suggest that the fe skarn mineralization formed under relatively oxidized conditions homogenization temperatures t h of all fluid inclusions and calculated salinity content are in the range of 166 c 462 c and 0 35 14 3 wt nacl equ respectively well defined positive correlation between th and salinity values indicates that meteoric water was involved in the hydrothermal solutions eutectic temperatures te between 40 8 c and 53 6 c correspond to the presence of cacl 2 in the early stage of fluid inclusions on the other hand the te temperatures of later stage fluid inclusions in the range of 38 c and 21 2 c correspond to the presence of mgcl 2 fecl 2 kcl and nacl type salt combinations none of the fluid inclusions were found to contain separated gas phases in microscopy observations however a limited amount of dissolved ch 4 was identified in the early stage high temperature fluid inclusions using raman spectroscopic studies 18 o values in both dolomitic limestone 10 8 12 5 and skarn calcite 7 6 9 8 were highly depleted compared to the typical 18 o values of marine limestones decreases in 18 o values are accepted as an indication of dilution by meteoric water because retrograde brecciation of garnet magnetite and breccia filling epidote and quartz in volcanic host rocks are an indication of increasing permeability allowing infiltration of meteoric water highly depleted 13 c isotopes up to 6 5 of dolomitic limestone indicate that organic matter in carbonates had an effect on the decreasing isotopic ratios the presence of ch 4 and ch 2 in fluid inclusions can be explained by the thermal degradation of these organic materials

causes of river avulsion insights from the late holocene avulsion history of the mississippi river u s a discussion our understanding of river avulsions is still in its infancy especially if we are to rationally predict how when and where avulsions will occur the recent paper by aslan et al 2005 sheds new light on the late holocene evolution of the lower mississippi valley with particular emphasis on the avulsion that led to the formation of the atchafalaya river although we welcome their contribution and agree with most of their conclusions we also feel that a key point raised in their paper is somewhat misleading aslan et al 2005 contend that factors other than gradient advantage notably the presence of buried sand bodies and or floodplain topography associated with residual channels are at least as important in determining the occurrence

titanite and zircon fission track dating resolves successive igneous episodes in the formation of the composite kackar batholith in the turkish eastern pontides the kackar batholith in the turkish eastern pontides comprises several intrusive units with distinctive textural mineralogical and geochemical characteristics their titanite and zircon fission track ages confirm that the different lithodem units result from consecutive igneous episodes establish their emplacement sequence and together with geochemical data help to relate them to their geodynamic context the camlikaya granitoid 112 4 1 6 ma was emplaced during an immature arc magmatic episode of early cretaceous age the sirtyayla 57 1 1 2 ma and marselevat 52 9 1 3 ma granitoids are late products of a late palaeocene mature arc episode the ayder granitoid 46 4 1 0 ma is the result of middle to late eocene post collisional magmatism related to slab break off the halkalitas quartz diorite 43 7 2 3 ma and the gullubag monzonite 38 1 0 9 ma document a middle to late eocene episode related to post collisional extension the data reveal the advantages of dense sampling spanning a maximum range of elevations apart from the increased precision on the mean redundant sampling allows to shift the basis for interpretation from a priori assumptions to a posteriori numerical criteria when using geochronometers with low to moderate closure temperatures including apatite titanite and zircon fission tracks but also k ar ar ar biotite muscovite and k feldspar

changes in channel size at river confluences with coarse bed material a field survey of thirty stream junctions from a small watershed together with data collected by miller 1958 allowed us to investigate morphometric adjustments occurring at confluences the model proposed by roy and woldenberg 1986 was slightly modified and used as a tool for morphometric analysis two parameters are necessary in order to evaluate the rate of change in channel size at a confluence the area ratio channel capacity above the confluence channel capacity below the confluence and the discharge ratio discharge of the minor tributary discharge of the major tributary our data show that total channel capacity tends to decline below most confluences a reduction in cross sectional area implies an increase in average flow velocity this interpretation is consistent with lyell s observations and with results from recent flume experiments best and reid 1984

petrology of the shoshonitic cambasi pluton in ne turkey and implications for the closure of the neo tethys ocean insights from geochemistry geochronology and sr nd isotopes abstract the eastern pontide orogenic belt epob is one of the well preserved continental magmatic arcs in the alpine himalayan belt and consists of paleozoic to miocene plutonic bodies this paper presents new geological bulk rock major and trace element analyses biotite ar ar ages and sr nd isotope data on representative samples from the cambasi granitic body exposed in the northwestern part of the epob although the majority of the plutons in the epob show calc alkaline affinity and i type character the cambasi pluton has a shoshonitic affinity and an i type metaluminous signature the pluton is composed of mainly monzonite quartz monzonite and granite bodies including monzo dioritic mafic microgranular enclaves mmes excluding the mmes these rocks have 57 7 70 2 wt sio2 13 1 17 5 wt al2o3 3 06 3 64 wt na2o 3 66 5 92 wt k2o 0 33 3 3 wt mgo and mg

latest cretaceous a 2 type granites in the sakarya zone ne turkey partial melting of mafic lower crust in response to roll back of neo tethyan oceanic lithosphere abstract an integrated study of comprehensive geochronological geochemical and sr nd hf isotopic data was undertaken for the a type topcam pluton that intruded within the sakarya zone ne turkey with the aims of elucidating its origin and tectonic significance and gaining new insights into the generation of aluminous a type granites new la icp ms zircon u pb crystallization ages of 72 and 73 ma indicate emplacement in the late cretaceous time just after extensive metaluminous i type magmatism in the area the pluton consists mainly of alkali feldspar quartz plagioclase amphibole and biotite with accessory minerals such as magnetite apatite and zircon the outcrop is composed of granite syenite monzonite and quartz monzonite and possesses a wide range of sio2 content 57 70 wt with elevated ga al ratios and low mg mostly

stratigraphic and structural development of the eastern pontides turkey this paper describes the stratigraphic and structural development of the eastern pontides north turkey based on section logging at eight localities construction of three structural profiles across the mountains and published literature the eastern pontides comprise a late carboniferous to miocene sequence resting on a basement of hercynian metamorphics late carboniferous to scythian sediments are continental clastics interpreted as having been deposited in an extensional half graben the middle triassic is limestone reflecting the development of a south facing passive margin in the late triassic the ocean palaeotethys began to close flysch was deposited in most places with minor shallow water limestones in the sinemurian above an inverted half graben all pre aalenian strata were deformed during the cimmerian orogeny after a phase of subduction related volcanism in the mid jurassic limestones were deposited during the late jurassic and early cretaceous mainly in shallow water the aptian and albian are absent due to doming in the western pontides prior to the opening of the western black sea but there is a thick sequence of upper cretaceous arc volcanic rocks and intervening turbidites the upper palaeocene is absent possibly due to rifting in the eastern black sea major compression affected the pontides from the eocene to the pliocene associated with the closure of the tethyan ocean oligocene and younger rocks are accordingly non marine

sediment transmission and storage the implications for reconstructing landform development the late holocene last 3000 years development of the lower ribble valley northwest england displays evidence for a complex response to a sediment recharge event forced by land use change induced increases in erosion and sediment delivery the deposition of fluvial sediments during the late holocene was restricted to a series of reaches or depocenters separated by zones with no sediment accumulation constrained by older glacial and fluvial terrain apparent reach wide correlations of fluvial terraces break down under the scrutiny applied by comprehensive and extensive radiocarbon control bayesian testing of relative order models show that large scale geomorphological changes e g the progression from one terrace level to another were time transgressive between different depocenters the different histories of sediment delivery and storage are probably a function of local and process scale variations in these depocenters and reflect dis connectivity relationships within a reach in propagating a basin scale change superslug in the sediment regime disconnectivity in the depositional regime through a fluvial reach limits what we can reconstruct in terms of sediment budgets but radiocarbon dating of multiple palaeochannels offers considerable potential for landform based research to uncover rates of change within individual depocenters copyright 2009 john wiley sons ltd

late holocene channel changes of the middle trent channel response to a thousand year flood record this paper presents recent work on the floodplain sedimentology of the middle trent using data from gravel pits archaeological sites and documentary sources the middle trent has been unusually active during the holocene in comparison with other large lowland rivers in the british isles the holocene floodplain fill is dominated by sands and gravels with abundant structural evidence of changes in channel pattern and channel type a thousand year record of channel change has been reconstructed from palaeochannels and gravel units with radiocarbon dating of brushwood palaeomagnetic dating of fine channel fills dendrochronological dating of timber structures and dating via archaeological typologies the trent also has a reasonably well recorded flood history at least since the 11th century ad a comparison of the flood record and channel change indicates that the same degree of morphological and sedimentary response is not necessarily associated with floods of similar magnitudes i e there is no constant relationship between event magnitude and landform change instead the response seems dependent on the existing state of the channel and medium term trajectory of channel change there is evidence at both the hemington and colwick reaches of a cycle of channel change involving a change in channel typology and dating evidence that this may have migrated downstream the results of this work provide a medium term perspective on channel change which may be more appropriate for large british rivers than short term monitoring for both model validation and planning purposes

the exhumation of the western greater caucasus a thermochronometric study this study provides 39 new thermochronometric analyses from the western part of the greater caucasus a region in which existing data are extremely limited and of questionable quality the new results are consistent with field studies that identify triassic to middle jurassic cimmerian and oligo miocene alpine orogenic erosional events an inverse relationship between the fission track and depositional ages of oligo miocene sedimentary samples also implies some degree of eocene erosion of the greater caucasus and intermediate sediment storage cooling ages and field relationships within the core of the range west of mt elbrus require 5 km of permo triassic exhumation and restrict the overall amount of cenozoic exhumation to 2 5 km current exhumation rates are typically low and do not support a plio pleistocene increase in climate driven denudation high 1 km ma 1 rates of exhumation are restricted to the southern flank of the range in northwest georgia despite a general lack of significant seismicity within the study region this exhumation peak is close to the largest instrumentally recorded earthquake in the caucasus ms 7 0 this may suggest that exhumation is associated with the decoupling of the sedimentary succession from its crystalline basement in the southern part of the range and the inversion of the largely jurassic fill of the greater caucasus basin rates of exhumation are compatible with this being driven by active shortening further sampling and analysis are required to provide a higher resolution low temperature thermochronology of alpine exhumation to isolate the drivers for palaeogene dziruli massif cooling and uplift and to constrain better the extent of the current localized phase of rapid exhumation

timing of post obduction granitoids from intrusion through cooling to exhumation in central anatolia turkey abstract the middle to late cretaceous central anatolian granitoids intrude the supra subduction zone type central anatolian ophiolite and medium to high grade metasediments of central anatolian crystalline complex and are overlain by late palaeocene to early middle eocene sediments their single zircon 207 pb 206 pb evaporation ages define three clusters 1 cenomanian turonian weighted mean age 94 9 3 4 ma 2 turonian santonian 85 5 5 5 ma and 3 campanian 74 9 3 8 ma their hornblende and biotite 40 ar 39 ar and k ar cooling ages cluster around 80 65 ma the close hornblende and biotite ages reflect rapid exhumation of a mid crustal section during the campanian maastrichtian early to middle palaeocene 57 62 ma apatite fission track age clusters date the tail end of this exhumation episode it is proposed that the central anatolian granitoid melts were generated in a post collisional extensional setting following the docking of an oceanic island arc onto the tauride anatolide platform campanian maastrichtian to early middle palaeocene rapid exhumation event is considered to result from continent continent collisions between eurasian plate and the tauride anatolide platform along the izmir ankara erzincan suture zone

petrogenesis of the post collisional volcanic rocks from the borcka artvin area implications for the evolution of the eocene magmatism in the eastern pontides ne turkey abstract whole rock geochemistry 40 ar 39 ar data and sr nd isotopes are presented for the eocene borcka volcanic rocks on the eastern corner of the eastern pontide orogenic belt ne turkey borcka artvin volcanic rocks are divided into three suites basic dyke borcka basalt and civankoy suite these rocks contain plagioclase an 49 88 clinopyroxene wo 38 49 en 38 54 fs 8 25 hornblende mg 0 57 0 74 phenocrysts and magnetite titanomagnetite and apatite microphenocrysts 40 ar 39 ar ages on hornblendes ranging from 46 9 0 1 to 39 9 0 5 ma within the middle eocene the volcanic rocks show tholeiitic calc alkaline affinities and have low to medium k contents they are enriched in large ion lithophile lile and light rare earth elements lree with pronounced depleted high field strength elements hfse the chondrite normalized ree patterns la cn lu cn 1 19 show low to medium enrichment indicating similar sources for the rock suite initial 87 sr 86 sr values 87 sr 86 sr 46 ma vary between 0 70423 and 0 70495 while initial 143 nd 144 nd values 143 nd 144 nd 46 ma lie between 0 51263 and 0 51285 the main solidification processes involved in the evolution of the volcanics consist of fractional crystallization with minor amounts of crustal contamination all our evidences support the conclusion that the parental magma of the rocks probably derived from an enriched mantle previously metasomatized by fluids derived from subducted slab in a post collisional extension related geodynamic setting

sediment transport and bed morphology at river channel confluences river channel confluences form important morphological elements of every river system being points at which rapid changes in flow sediment discharge and hydraulic geometry must be accommodated this article presents results of a quantitative investigation of sediment transport at channel confluences accomplished through both scaled laboratory flume simulation and complementary monitoring of a natural channel confluence bed morphology at channel confluences is characterized by three distinct elements avalanche faces at the mouth of each confluent channel a deep central scour and a bar within the separation zone formed at the downstream junction corner these elements are controlled predominantly by the confluence angle and the ratio of discharges between the tributary and mainstream channels as confluence angle and discharge ratio increase the sediment contributions from the confluent channels are progressively segregated in their paths through the junction with sediment being transported around rather than through the centre of the confluence this segregation of sediment loads is accompanied by the retreat of the main channel avalanche face from the confluence an increase in the scour depth a change in the orientation of the scour and an increase in the size of the separation zone bar field measurements closely replicate the flume simulation a model of sediment transport and bed morphology links these features to the fluid dynamics of these sites an understanding of confluence dynamics is important not only in considerations of channel morphology and design criteria but must form the basis for the interpretation of confluence sediments in the ancient record

relationship between sediment supply and avulsion frequency in braided rivers the interplay between sediment supply s s sedimentation rate s r and the frequency of channel avulsion a f exerts a primary control on alluvial architecture in order to investigate the effect of sediment supply on avulsion frequency four froude scale model experiments of an aggrading braided river were undertaken in which the magnitude of s s was progressively increased over an eightfold range the value of a f increases at a rate slower than the increase in s s contrary to the trend previously reported by bryant falk and paola in their experimental study on alluvial fan dynamics these results suggest that the relationship between a f and s s is dependent upon bed slope and that the response of a f to an increase in s s in unconfined braided rivers may be different than that on steep alluvial fans

geochemical characteristics of the composite kackar batholith generated in a neo tethyan convergence system eastern pontides turkey abstract the composite kackar batholith of cretaceous to late eocene age consists of various intrusions derived from different geodynamic settings ranging from early to mature arc through collision to post collisional extension in the neo tethyan convergence system of the eastern pontides of ne turkey the intrusions were emplaced into cretaceous and middle eocene volcano sedimentary units and are unconformably overlain by late cretaceous early to middle eocene and miocene units the 10 lithological units are grouped into five geodynamic associations on the basis of geological setting and geochemical characteristics 1 early arc origin as represented by the medium k calc alkaline calk camlikaya granitoid of early cretaceous age 2 mature arc origin as represented by the medium to high k calc alkaline sirtyayla and marselevat granitoids of late cretaceous to early palaeocene age 3 syn collisional plutonism as represented by the peraluminous asniyor leucogranite of palaeocene age 4 post collisional plutonism as represented by the high k calc alkaline ayder k feldspar megacrystic granitoid and the sasmistal microgranite of middle to late eocene age 5 the extension related mildly alkaline gullubag monzonite the medium k calc alkaline to slightly tholeiitic thol halkalitas quartz diorite and the low k tholeiitic ardesen gabbro and isina diabase of late eocene age that are mainly exposed as small shallow stocks and n s ne sw nw se and e w trending veins

necessary conditions for a meandering river avulsion there is as yet no rational basis for predicting the conditions leading to avulsion of a meandering river here we present a conceptual model and quantify it under simplifying assumptions as a first step toward the construction of a stability diagram for avulsion initiation it is assumed initially that a rectangular crevasse channel of arbitrary depth is cut into the levee of a meandering river because the water entering the crevasse channel is derived from relatively high in the main flow it contains low concentrations of suspended solids consequently the crevasse flow is under capacity and the entrance is eroded deepening of the entrance increases the crevasse channel discharge and the concentration of suspended solids supplied because more sediment laden waters are tapped from the deeper flow in the main channel the crevasse entrance is predicted to deepen until its sediment carrying capacity is satisfied by the suspended solids entering from the main channel whether an avulsion will occur for a particular combination of initial conditions depends upon whether there exists steady state hydraulic and sediment transport conditions for crevasse channel depths that are equal to or less than the main channel depth this conceptual model is quantified by writing the unsteady gradually varied one dimensional conservation of mass and momentum equations for water and sediment transport through a main and crevasse channel sediment transport is computed as the integral of a cross sectional mean velocity and a rouse concentration profile solutions show that stable crevasse channels exist only for particular combinations of the initial height of the crevasse bed relative to the water depth in the main channel and the ratio of initial crevasse bed slope to main channel slope

kinematic and thermal evolution of the haymana basin a fore arc to foreland basin in central anatolia turkey abstract gondwana tauride kirsehir blocks and eurasia pontides derived continental blocks delimit the haymana basin central turkey to the south and the north respectively the boundaries of these blocks define the izmir ankara erzincan and intra tauride suture zones which are straddled by a number of late cretaceous to oligocene marine to continental basins the haymana basin is located at the junction of the iaesz and itsz and comprises upper cretaceous to middle eocene basin infill deposited in response to the interaction of these blocks the basin provides a unique opportunity to unravel spatio temporal relationships related to the timing of late stage subduction history of neo tethys ocean and subsequent collision of the intervening continental blocks we have conducted a multidisciplinary study in the region that includes mapping of major structures combined with fault kinematic analyses e w striking folds dominate the basin cross section balancing of these structures indicates around 25 roughly n s shortening in the region paleostress studies indicate that the basin was initially subjected to n s to nne ssw extension until the middle paleocene phase 1 and then n s directed syn depositional compression and coeval e w directed extension until the middle miocene phase 2 implying strike slip deformation and pure shear shortening in the basin these different deformation phases are attributed to first fore arc subduction basin development then foreland collision stages of the basin apatite u th he dating of 5 samples indicate that exhumation of the se segment of the basin started in early oligocene whereas the nw segment of the basin exhumed in the early miocene the differential uplift is possibly related to progressive north westwards movement of derekoy basin bounding fault at the north we propose that the haymana basin evolved from extensional forearc basin during the late cretaceous to early paleocene and foreland basin after the terminal subduction and subsequent collision of tauride and pontide blocks

207pb 206pb single zircon evaporation ages of some granitoid rocks reveal continent oceanic island arc collision during the cretaceous geodynamic evolution of the central anatolian crust turkey abstract 207pb 206pb single zircon evaporation age determinations carried out on nine different granitoid units of central anatolia turkey have yielded three distinct granitoid groups with different emplacement ages these are 1 cenomanian turonian granitoids with a weighted mean age wma of 94 9 3 4 ma 2 turonian santonian granitoids with a wma of 85 5 5 5 ma and 3 campanian granitoids with a wma of 74 9 3 8 ma the spatial and temporal relationships between the formation of the metamorphic sole of the supra subduction zone type central anatolian ophiolite ssz type cao crustal metamorphism of the central anatolian crystalline complex cacc and the emplacement of cenomanian turonian to turonian santonian granitoids indicate a geodynamic setting in which all these geological events occurred quasi simultaneously in central anatolia such a geodynamic setting is thought to be related to the cenomanian turonian collision of the tauride anatolide platform tap and an oceanic island arc including the ssz type cao the campanian granitoids appear to be the continuation of this collision related protracted magmatism in central anatolia