u th dating of striated fault planes direct dating of brittle fault activity is of fundamental importance to tectonic reconstructions and paleoseismic studies one way to address this issue is by constraining the timing of fault striations but this requires a better understanding of the striation formation mechanism and associated mineralization we present results from a microstructural geochemical and geochronological study of calcite precipitates associated with striated fault planes from the dead sea fault zone in northern israel we recognize four types of coexisting calcite precipitates including calcite cement in dilation breccia calcite in striated groove morphology calcite gouge associated with hydraulic fracturing and pressure solution and calcite coating of the fault surface carbon oxygen isotopes 87sr 86sr ratios and rare earth element and yttrium rey patterns indicate various precipitation mechanisms associated with formation of syntectonic calcite cement and striations coseismic calcite gouge and interseismic calcite coating precipitates in the fault zone using u th dating of samples from three adjacent fault planes we delineate four welldefined deformation ages in the period from 220 to 60 ka we conclude that these ages constrain the timing of activity along the dead sea fault zone in northern israel and argue that a similar methodological approach could potentially shed light on the timing of deformation in other brittle fault zones

the deep structure of the north anatolian fault zone abstract multi scale full waveform inversion of complete continental and regional scale seismograms reveals the crustal and upper mantle signature of the north anatolian fault zone which shapes the neotectonics of turkey and the eastern mediterranean within the crust the fault zone is mostly bounded by several high velocity blocks suggesting that it developed along the edges of continental fragments with high rigidity below the crust the surface expression of the eastern and central parts of the north anatolian fault zone correlate with a pronounced low velocity band that extends laterally over 600 km around 100 km depth the low velocity band merges into the shallow anatolian asthenosphere thereby providing a link to the kirka afyon isparta volcanic field and the central anatolian volcanics we interpret the low velocity band beneath the north anatolian fault zone as the upper mantle expression of the tethyan sutures that formed 60 15 ma ago as a result of africa eurasian convergence the structurally weak suture facilitated the formation of the younger less than 10 ma crustal fault zone in this sense the north anatolian fault zone is not only a crustal feature but a narrow zone of weakness that extends into the upper mantle

rare earth elements as indicators of groundwater environment changes in a fractured rock system evidence from fracture filling calcite rare earth element ree abundances in core samples from precambrian crystalline rocks at the samkwang mine site provide evidence of the solution chemistry involved in precipitation of calcite on fractures the rock types collected in core samples are mainly banded gneisses with mineral assemblages dominated by biotite k feldspar quartz and plagioclase calcite chlorite muscovite and sericite occur as secondary minerals with calcite being the main filling material in fractures in general the core samples from 4 boreholes are enriched in light ree lree and depleted in heavy ree hree with negative eu anomalies however positive eu anomalies also occur at specific depths within 3 boreholes variation of chondrite normalized ree patterns results from the fracture filling calcite in core samples calcite fracture fillings provide a record of paleo hydrology where eu has been reduced and selectively concentrated in the solutions from which calcite has precipitated

backarc rifting constructional volcanism and nascent disorganised spreading in the southern havre trough backarc rifts sw pacific high resolution multibeam em300 and seabeam data of the southern havre trough sht combined with observations and sample collections from the submersible shinkai6500 and deep tow camera are used to develop a model for the evolution and magmatism of this backarc system the havre trough and the associated kermadec arc are the product of westward subduction at the pacific australian plate boundary detailed studies focus on newly discovered features including a seamount saito seamount and a deep graben ngatoroirangi rift 4000 m water depth floored with a constructional axial volcanic ridge 5 km in length and in excess of 200 m high both of which are characterised by pillow and lobate flows estimated at elongate volcanic ridges at 35 15 s and 34 30 s and backarc seamounts 35 30 s 178 30 e occur at the eastern margin of the sht similar seafloor morphology is observed in the central and western portions of the basin suggesting that recent volcanism may be broadly distributed across the backarc mass balance modelling indicates a maximum crustal thickness of 11 km to 4000 m spreading systems these discontinuous spreading systems are characterised by failed rifts rift segmentation and propagation successive episodes of magmatic intrusion into thinned faulted arc basement results in defocused asymmetrical accretion cross arc volcanic chains isolated volcanoes and underlying basement plateaus are interpreted to represent a cap of recent extrusives however they may also be composed entirely of newly accreted crust and the spatially extensive basement fabric of elongated volcanic ridges may be the surface expression of pervasive dike intrusion that has thoroughly penetrated and essentially replaced the original arc crust with newly accreted intrusives

evidence for episodic cementation and diagenetic recording of seismic pumping events north coles levee california u s a abstract bands of calcite and dolomite cements alternating with zones of nearly carbonate free sand occur in the stevens sandston aat north coles levee san joaquin valley california temperatures calculated from o isotopes suggest that the calcite cement bands were emplaced episodically as a result of repeated injections of hot water from deeper in the section burial analysis suggests that these cements precipitated from 7 ma to the present over the temperature range of 45 to 95 c carbon isotope data suggest that the c in the cements is a mixture derived from two sources detrital shell material 13c pdb and co2 liberated from maturing kerogen 13c 24 plots of 13c vs time and depth of crystallization show that the cementation sequence was 1 dolomite cements possibly concretionary precipitated at depths a log of 13c vs calculated depth of crystallization correlates with the stratigraphic column at north coles levee if the correlation is valid the light 13 in each cement sample can be tied to its source a model based on this interpretation suggests that the early light c was derived from maturing kerogen in the kreyenhagen formation eocene as it passed through the oil window between 4 and 5 ma the subsequent passage of younger sediments with less organic material produced correspondingly smaller amounts of light co2 which was reflected in the relatively heavier c isotopes in the later cements it is suggested that the epidsodic injections of hot water carried dissolved gases and minerals principally calcite upward from rocks as deep as 2 3 km below the stevens sandstone and reprecipitated the calcite in more permeable zones in the rock degassing of co2 from rising pore waters likely triggered the precipitation and accounts for the relatively large volumes of cement the sibson model for seismic pumping of pore fluids is considered a likely explanation for the observed cementation

sedimentation in pull apart basins active examples in eastern turkey the erzincan susehri niksar and lake hazar basins are actively evolving pull apart basins in eastern turkey their structural drainage and depositional systems generally support a pull apart basin sedimentation model based on ancient pull apart basin deposits this model involves marginal coarse grained sedimentation adjacent to master faults axial fine grained sedimentation away from master faults and high sedimentation rates however studies of the turkish pull apart basins suggest the following refinements in the model 1 detailed sedimentary facies patterns and the dominant facies of a pull apart basin vary according to basin shape climate drainage character and volcanic activity depositional environments near fault bounded margins include alluvial fan fan delta and alluvial apron depositional environments in central areas away from fault bounded margins include active braid plain inactive braid plain meander plain salt playa marsh lacustrine mouth bar delta and volcanic 2 i

geodynamic control on carbonate diagenesis petrographic and isotopic investigation of the upper jurassic formations of the paris basin france abstract the oxfordian and kimmeridgian carbonates of the eastern edge of the paris basin display poor reservoir properties stable isotope investigation of these non recrystallized cements through both microdrilling sampling and in situ sims secondary ion mass spectrometry analysis shows that they originated from slightly buffered meteoric fluids 3 smow to 8 smow flowing through the malm carbonate aquifers of the eastern edge of the paris basin after a review of the post upper jurassic history of the paris basin it appears that meteoric water supplies leading to such cementations were associated with the evolution of the basin s geodynamic setting and notably with the lcu late cimmerian unconformity major event which corresponds to the uplift of the london brabant massif denudation of the oxfordian and kimmeridgian carbonates on the southern flank of the london brabant massif to the north of the study area then lead to lateral recharging of the associated aquifers with meteoric fluids this scenario is similar to the one proposed to explain cementations of the jurassic carbonates in the wessex weald basins which emphasizes the main role played by the cretaceous unconformities over carbonate diagenesis at the scale of the northwestern tethys margin

microstructural observations on natural syntectonic fibrous veins implications for the growth process abstract syntectonic antitaxial and ataxial fibrous veins were investigated using sem microprobe cathodoluminescence cl and optical microscopy in antitaxial calcite veins fibres and surrounding selvage grew simultaneously with similar growth rates of crystallographically differently oriented grains new material precipitated at the vein margin in antitaxial and bi mineralic ataxial microstructures bridges of country rock material formed during vein growth in an initial en echelon vein system in our antitaxial and bi mineralic ataxial samples the spacing of solid inclusions does not reflect individual crack seal openings

paleogeographic evidence on the jurassic tectonic history of the pontides new paleomagnetic data from the sakarya continent and eastern pontides the jurassic paleogeographic position of the pontides is not well studied because of insufficient paleomagnetic data for this reason a paleomagnetic study was carried out in order to constrain the paleolatitudinal drift of the turkish blocks during the jurassic period a total of 32 sites were sampled from volcanic and volcanoclastic rocks of the lower middle jurassic kelkit formation eastern pontides mudurnu formation sakarya continent and upper jurassic lower cretaceous ferhatkaya formation exposed around amasya region eastern pontides rock magnetic experiments demonstrate that the main ferromagnetic mineral is pseudo single domain titanomagnetite in these rocks paleomagnetic analysis revealed two main components of the natural remanent magnetization during stepwise thermal and alternating field demagnetization the first component is a low coercivity unblocking temperature component with a direction sometimes similar to that of the earth s present field or a viscous component the second component which is interpreted as the characteristic remanent magnetization chrm direction has low to high coercivity properties between 20 and 100 mt or unblocking temperatures between 300 and 580 c a positive fold test at the 95 level of confidence proved that the chrm of the sites is primary paleomagnetic directions calculated for the kelkit formation in the eastern pontides have a mean direction of d 334 8 i 49 7 95 7 1 after tilt correction a mean direction of d 332 2 i 48 5 95 14 6 was obtained from the volcanoclastic rocks of the mudurnu formation and d 324 3 i 43 3 95 9 5 was calculated for the upper jurassic lower cretaceous limestones ferhatkaya formation of the amasya region the jurassic rocks in the eastern pontides and mudurnu region are considered to represent products of the rifted neo tethys ocean while the upper jurassic lower cretaceous sediments in amasya are related to basin filling materials the data suggest that the kelkit formation was formed at 30 5 n paleolatitude and the equivalent mudurnu formation at 29 5 n paleolatitude the paleolatitude of the eastern pontides indicates that this rifting block was separated from eurasia by a marginal basin instead of being a part of eurasia the lower paleolatitude of the amasya region at 24 8 n in the upper jurassic to lower cretaceous clearly indicates southward drift of the turkish blocks during the jurassic to lower cretaceous period together with the motion of eurasia

fluids along the north anatolian fault niksar basin north central turkey insight from stable isotopic and geochemical analysis of calcite veins abstract six limestone assemblages along the north anatolian fault naf niksar pull apart basin in northern turkey were analyzed for 18opdb and 13cpdb using bulk isotope ratio mass spectrometry irms matrix vein differences in 18opdb 2 1 to 6 3 and 13cpdb 0 9 to 4 6 suggest a closed fluid system and rock buffering veins in one travertine and two limestone assemblages were further subjected to cathodoluminescence trace element laser ablation inductively coupled plasma mass spectrometry and 18opdb secondary ion mass spectrometry sims analyses fluid inclusions in one limestone sample yield th of 83 8 7 3 c 1 mean average sims 18opdb values across veins show fine scale variations interpreted as evolving thermal conditions during growth and limited rock buffering seen at a higher resolution than irms rare earth element data suggest calcite veins precipitated from seawater whereas the travertine has a hydrothermal source the 18osmow fluid for the mineralizing fluid that reproduces th is 2 in range of cretaceous brines as opposed to negative 18osmow fluid from meteoric groundwater and geothermal sites in the region and highly positive 18osmow fluid expected for mantle derived fluids calcite veins at this location do not record evidence for deeply sourced metamorphic and magmatic fluids an observation that differs from what is reported for the naf elsewhere along strike

novel applications of fluid inclusions and isotope geochemistry in unravelling the genesis of fossil travertine systems the denizli basin is a fault bounded neogene quaternary depression located in the western anatolian extensional province western turkey the basin is a unique geological site with abundant active and fossil quaternary travertine and tufa deposits fluid inclusion microthermometry and isotopic analysis were applied to study the genesis of the ballk fossil travertine deposits located in the south eastern part of the basin microthermometry on fluid inclusions indicates that the main travertine precipitating and cementing fluids are characterized by low salinity 07wt nacl equivalent and variable temperatures that cluster at 50 degrees c and ca 100 degrees c fluids of meteoric origin have been heated by migration to the deeper subsurface possibly in a local high geothermal gradient setting a later uncommon cementation phase is related to a fluid with a significantly higher salinity 255 to 260wt bulk the fluid obtained its salinity by interaction with late triassic evaporite layers strontium isotopes indicate that the parent carbonate source rock of the different travertine precipitates is very likely to be the triassic limestone of the lycian nappes carbon isotopes suggest that the parent co2 gas originated from thermal decarbonation of the lycian limestones with minor contributions of magmatic degassing and organic soil co2 oxygen isotopes confirm the meteoric origin of the fluids and indicate disequilibrium precipitation because of evaporation and degassing results were integrated within the available geological data of the denizli basin in a generalized travertine precipitation model which enhanced the understanding of fossil travertine systems the study highlights the novel application of fluid inclusion research in unravelling the genesis of continental carbonates and provides several recommendations for hydrocarbon exploration in travertine bearing sedimentary basins the findings suggest that travertine bodies and their parent carbonate source rocks have the potential to constitute interesting subsurface hydrocarbon reservoirs

faulting associated with historical and recent earthquakes in the eastern mediterranean region summary this paper summarizes evidence for surface faulting in historical and recent earthquakes in the eastern mediterranean region and in the middle east such information is particularly important for studies of active tectonics and for palaeoseismology we have found 78 cases of faulting pre 1900 and 72 post 1900 some of which show that faults that have apparently been inactive this century had already ruptured before 1900 for some cases faulting could not have been predicted from 20th century activity and in others it could have been expected but has not been observed during the instrumental period the data are suycient to allow the derivation of relationships between magnitude and rupture length

the influence of fault geometry on small strike slip fault mechanics abstract meter scale subvertical strike slip fault traces in the central californian sierra nevada exhibit geometric complexities that significantly contribute to their mechanical behavior sections of faults that opened at depth channelized fluid flow as evidenced by hydrothermal mineral infillings and alteration haloes thin sections show a variation in the style of ductile deformation of infill along the fault with greater intensities of deformation along restraining bends orthorectified photomosaics of outcrops provide model geometries and parameter constraints used in a two dimensional displacement discontinuity model incorporating a complementarity algorithm model results show that fault shape influences the distribution of opening and consequently the spatial distribution of fluid conduits geometric irregularities are present at many scales and sections of opening occur along both releasing and restraining bends model sensitivity tests focus on boundary conditions along the fault frictional properties on closed sections and fluid pressure within sections of opening the influence of the remote stress state varies along a non planar fault complicating the relationships between remote stresses frictional properties slip and opening discontinuous sections of opening along model faults are similar in spatial distribution and aperture to the epidote infill assemblages observed in the field

morphology displacement and slip rates along the north anatolian fault turkey 1 geological and geomorphological offsets at different scales are used to constrain the localization of deformation total displacement and slip rates over various timescales along the central and eastern north anatolian fault naf in turkey the naf total displacement is reevaluated using large rivers valleys 80 15 km and structural markers pontide suture 85 25 km tosya vezirkopru basins 80 10 km these suggest a neogene slip rate of 6 5 mm yr over 13 myr the river network morphology shows offsets at a range of scales 20 m to 14 km across the main fault trace and is also used to estimate the degree to which deformation is localized at a smaller scale the morphology associated with small rivers is offset by 200 m along the naf the age of these features can be correlated with the holocene deglaciation and a slip rate of 18 3 5 mm yr is determined this is consistent with a rate of 18 5 mm yr deduced independently from the 14c dating of stream terrace offsets over the short term gps data gives a similar rate of 22 3 mm yr all our results tend to show that most of the deformation between the anatolian and eurasian lithospheric plates has been accommodated along or very close to the active trace of the naf the difference between the neogene and the holocene slip rate may be due to the recent establishment of the current plate geometry after the creation of the naf

rock buffered fluid rock interaction in deformed quartz rich turbidite sequences eastern australia quartz vein 18o 16o ratios across a 500 km transect through the lachlan fold belt of southeastern australia are remarkably uniform 1 1 5 permil at both local centimeter to meter and regional over 104 km2 scales they define isotopic zones that correlate with the tectonic divisions of the cambrian through devonian dominantly ordovician quartz rich turbidites determined by regional mapping from west to east these divisions are 1 stawell 18o 14 7 1 1 47 samples 2 bendigo ballarat 18o 17 5 1 3 204 samples 3 melbourne 18o 19 0 1 6 80 samples 4 tabberabbera 18o 16 3 1 9 12 samples and 5 omeo 18o 14 4 1 0 26 samples isotope profiles across zone boundaries and intrazone fault zones particularly within the bendigo ballarat zone show steps indicating abrupt changes across faults with little or no evidence of fluid mixing within the fault zones 18o values of veins are insensitive to relative age type of vein and immediate host rock lithologies the 18o values of coexisting vein and host rocks show nonequilibrium relationships which can be explained in terms of rock buffering under conditions of low fluid rock ratios water rock 1 limited d h determinations on fluid inclusions fall mainly in the range 70 and 100 with one value as low as 140 these low deuterium values when considered in the context of paleolatitude may have been inherited from deutrium depleted detrital minerals and do not necessarily require the direct penetration of meteoric fluids to midcrustal depths the work suggests that vein formation is possible in regions where the integrated water rock w r ratio is very low w r 1 as long as a pervasive fluid phase is present this fluid appears to achieve a steady state isotopic composition on scales of hundreds of meters and once a quasi steady state has been reached the isotopic compositions of the resultant quartz veins are rather insensitive to the diachronous and nonisothermal conditions under which vein growth occurs advective cycling of the fluid on this scale is by episodic dilatancy pumping in fracture networks associated with localized faulting

carbon dioxide earth degassing and seismogenesis in central and southern italy 1 we present the first regional map of co2 earth degassing from a large area most of central and south italy derived from the carbon of deep provenance dissolved in the main springs of the region the investigation shows that a globally significant amount of deeply derived co2 10 of the estimated global co2 emitted from subaerial volcanoes is released by two large areas located in western italy the anomalous flux of co2 suddenly disappears in the apennine in correspondence to a narrow band where most of seismicity concentrates here at depth the gas accumulates in crustal traps generating co2 overpressurized reservoirs which induce seismicity

discriminating between different genetic types of marine ferro manganese crusts and nodules based on rare earth elements and yttrium marine ferro manganese fe mn crusts and nodules are metal rich chemical sediments that are archives of paleoceanographic proxies and potential metal resources and targets of deep sea mining traditionally crusts and nodules are subdivided into hydrogenetic diagenetic and hydrothermal types because these are characterized by different compositions and hence economic resource potential a useable genetic classification is not only a tool for geochemical studies but may also help to characterize potential exploration targets we propose two easy to use yet robust discrimination diagrams based on geochemical relationships controlling the rare earths and yttrium rey inventory of marine fe mn oxyhydr oxide deposits the rey are a set of trace elements that show coherent behavior are routinely determined in geochemical studies and for which the analytical quality can easily be evaluated graphs of ce anomaly vs nd concentration and ce anomaly vs y anomaly effectively discriminate between the different types of precipitates regardless of their diverse mineralogical composition both hydrogenetic crusts and nodules show positive ce anomalies negative y anomalies and high nd concentrations of 100 mg kg 1 although nodules tend to have slightly lower nd concentrations than crusts in marked contrast hydrothermal deposits generally yield negative ce anomalies positive y anomalies and low nd concentrations of 10 mg kg 1 in spite of their large geochemical mineralogical and sedimentological diversity diagenetic nodules show negative ce anomalies negative y anomalies and intermediate nd concentrations between 10 and 100 mg kg 1 we discuss the geochemical background of these diagrams the respective sources of rey in the different precipitates and address the processes that control their rey inventory besides the three end members we also use rey systematics to define mixed type diagenetic hydrogenetic nodules and classify well studied international reference standards

development of pull apart basins a comparative study of well mapped active and ancient pull apart basins suggests a qualitative model for their continuous development pull aparts evolve from incipient to extremely developed basins through a sequence of closely related states new and compiled map data from several areas including the northern caribbean and turkey suggests the following stages in pull apart development 1 in rigid intracontinental strike slip plate boundary zones larger pull aparts nucleate at releasing fault bends along segments of the principal displacement strike slip fault zone which are oblique to the theoretical interplate slip lines 2 initial opening across releasing fault bends produces spindle shaped basins defined and often bisected by oblique slip faults connecting the discontinuous ends of the strike slip faults 3 increased strike slip offset produces basin shapes which we colloquially call lazy s shape for basins between sinistral faults and lazy z shape for basins between dextral faults 4

genesis of the dogankuzu and mortas bauxite deposits taurides turkey separation of al fe and mn and implications for passive margin metallogeny the taurides region of turkey is host to a number of important bauxite al rich laterite and mn deposits the most important bauxite deposits dog ankuzu and mortas are karst related unconformity type deposits in upper cretaceous limestone the bottom contact of the bauxite ore is undulatory and bauxite fills depressions and sinkholes in the footwall limestone whereas its top surface is concordant with the hanging wall limestone the thickness of the bauxite varies from 1 to 40 m and consists of bohmite hematite pyrite marcasite anatase diaspore gypsum kaolinite and smectite the strata bound sulfide and sulfate bearing low grade lower part of the bauxite ore bed contains pyrite pseudomorphs after hematite and is deep red in outcrop owing to supergene oxidation the lower part of the bauxite body contains local intercalations of calcareous conglomerate that formed in fault controlled depressions and sinkholes bauxite ore is overlain by fine grained fe sulfidebearing and calcareous claystone and argillaceous limestone which are in turn overlain by massive compact limestone of santonian age that 50 m thick limestone is in turn overlain by well bedded bioclastic limestone of campanian or maastrichtian age rich with rudist fossils fracture fillings in the bauxite orebody are up to 1 m thick and consist of bluish gray green pyrite and marcasite 20 with bohmite diaspore and anatase these sulfide veins crosscut and offset the strata bound sulfide zones sulfur for the sulfides was derived from the bacterial reduction of seawater sulfate and fe was derived from alteration of oxides in the bauxite iron sulfides do not occur within either the immediately underlying or overlying limestone the platform limestone and shale that host the bauxite deposits formed at a passive margin of the tethys ocean extensive vegetation developed on land as the result of a humid climate thereby creating thick and acidic soils and enhancing the transport of large amounts of organic matter to the ocean alteration of the organic matter provided co2 that contributed to formation of a relatively 12 c rich marine footwall limestone relative sea level fall resulted from strike slip faulting associated with closure of the ocean and local uplift of the passive margin that uplift resulted in karstification and bauxite formation in topographic lows as repre

the geochemistry of rare earth elements in groundwater from the carnmenellis area southwest england shallow groundwater samples from the carnmenellis area of southwest england collected from wells boreholes springs adits and stream baseflow represent recently recharged waters of low salinity their major ion concentrations closely reflect the lithology of their host rocks which comprise the carnmenellis granite and devonian metasediments and metabasite of greenschist grade groundwaters from the granite are predominantly na cl or na ca cl type whilst those from the metasediment are na ca mg cl hco3 waters with a larger range of compositions the major ion compositions are predominantly a function of water rock interaction processes and the larger range of metasediment water compositions probably reflects the greater lithological variation the ph of groundwater samples circulating through granite is typically lower than that of groundwater in the metasediments the range being 4 3 to 7 2 median 5 7 and 4 7 to 8 0 median 6 6 respectively rare earth element ree concentrations of 0 45 m filtered groundwater samples have been determined by inductively coupled plasma mass spectrometry icp ms a large range of concentrations exists and many are below detection limits but levels reach up to 229 g 1 1 6 m total rees the rees are strongly controlled by ph with higher levels in groundwaters of ph 6 chondrite normalised profiles are light rare earth element lree enriched compared to heavy rare earths hrees with a common slight negative eu anomaly both features reflecting the compositions of their host rocks ree profiles therefore appear to be controlled by water rock interactions involving predominantly ree enriched minerals in the granite the rees are probably derived mainly from the accessory minerals monazite and apatite as well as the high ree framework minerals biotite and muscovite the source of rees in groundwater from the metasediments is more uncertain but probably includes clay minerals chlorite and carbonate ree compositions normalised to shale have flatter profiles although many are slightly convex with higher normalised sm eu and gd values a few metasediment derived waters with high total ree concentrations have lree enriched shale normalised patterns it is suggested that the bulk of the rees in these few samples is colloidal rather than totally dissolved groundwaters from the metasediments have a notable depletion in ce which is distinct from waters in the granite this depletion is problematic in that it is difficult to see how redox processes could be the dominant control since groundwaters from the metasediments are unlikely to be more oxidising than those from the granite likewise variations in ph fail to totally explain the distinctions in ce concentration and la ce ratios between the two water types it is therefore suggested that the ce contents are largely source related rather than process related the observed ree compositions of granite and metasedimentderived groundwaters from the carnmenellis area are so distinctive that the rees in general and ce in particular might be useful as future tracers in studies of water rock interaction and groundwater provenance

snow contribution to first year and second year arctic sea ice mass balance north of svalbard the salinity and water oxygen isotope composition 18o of twenty nine first year fyi and second year syi arctic sea ice cores total length 32 0 m from the drifting ice pack north of svalbard were examined to quantify the contribution of snow to sea ice mass five cores total length 6 4 m were analyzed for their structural composition showing variable contribution of 10 30 by granular ice in these cores snow had been entrained in 6 to 28 of the total ice thickness we found evidence of snow contribution in about three quarter of the sea ice cores when surface granular layers had very low 18o values snow contributed 7 5 9 7 to sea ice mass balance on average including also cores with no snow using 18o mass balance calculations in syi cores snow fraction by mass 12 7 16 3 was much higher than in fyi cores 3 3 4 4 while the bulk salinity of fyi 4 9 was distinctively higher than for syi 2 7 we surmise that oxygen isotopes and salinity profiles can give information on the age of the ice and allows to distinguish between fyi and syi or older ice in the area north of svalbard this article is protected by copyright all rights reserved

distributed neotectonic deformation in the anatolides of turkey a palaeomagnetic analysis abstract the palaeotectonic phase of deformation in anatolia accompanied closure of the tethyan ocean and was finally completed with sealing of the bitlis suture bordering the arabian shield at 12 ma arabia has since continued to indent the collage of terranes accreted to the eurasian margin by differential northward movement relative to africa along the dead sea fault zone and counterclockwise ccw rotation accompanying the opening of the red sea this neotectonic phase of deformation has accompanied uplift of the anatolian plateau and establishment of intracontinental transforms comprising the north and east anatolian fault zones deformation has included extrusion and rotation of blocks away from the arabian syntaxis by tectonic escape we produce an updated summary of palaeomagnetic results from this region to show that deformation has been distributed so that block rotations vary systematically across anatolia ranging from strongly ccw in the zone of high strain north of the arabian indenter to near zero in central anatolia and then progressively cw in western anatolia new palaeomagnetic results from the ankara igneous district are also reported and help to constrain the east to west change from ccw to cw rotation within central anatolia the transition of tectonic regimes from compression in the east to extension in the west involves the expulsion of blocks and their rotation along arcuate strike slip faults at an acute angle to the maximum compressive stress 1 between arabia and eurasia the comparable distribution of rotations in palaeotectonic and neotectonic units indicates that the bulk of the observed palaeomagnetic rotations have been concentrated within the last plio pleistocene phase of the neotectonic era as is found in the aegean domain to the west and has involved blocks of the order of 100 km in size the weak collage of accretionary terranes sandwiched between the arabian indenter and the eurasian margin now defined by the north anatolian fault zone has evidently taken up the bulk of the strain imparted by the continuing northward motion of arabia to expand the radius of the tauride arc and the perimeter of extruded crust bordering the limit of the extensional province in western turkey the distributed character of neotectonic deformation is illustrated by equivalent polar distributions both palaeotectonic and neotectonic palaeomagnetic poles show arcuate distributions with poles to best fitting small circles focussed close to the study area differences between the distributed neotectonic deformation resolved from palaeomagnetism and the contemporary gps record reflect the contrasting time periods being evaluated the palaeomagnetic record incorporates evolving and changing tectonic regimes whereas the gps signature has no long term validity within the weak anatolian collage hence the full spectrum of techniques for resolving neotectonic deformation is relevant to unravelling deformation in such regions

geochemical constraints on the origin and migration of palaeofluids at the northern margin of the variscan foreland southern belgium three major fracture types in the dinantian of the namur syncline at the northern margin of the variscan foreland in southern belgium have been investigated by fluid inclusion and stable isotope analysis the oldest and volumetrically most important fracture type is characterized by conjugated and sigmoidal en echelon calcite veins which formed during the variscan folding these veins and the surrounding limestones have both a similar dull brown orange luminescence and stable isotopic composition 18o 11 to 8 pdb and 13c 0 to 3 pdb this indicates precipitation of the calcite cement from a fluid buffered by the rock in the area studied only a limited amount of fluids was expelled through the dinantian during the main phase of variscan compressional tectonism fractures filled with ferroan calcites cross cut the variscan folds fluid inclusion and stable isotopic evidence indicates that the calcites precipitated at 40 60 c from a saline fluid 9 2 to 23 2 eq wt nacl with an estimated 18o composition between 2 0 and 0 6 smow the most likely origin of these high salinity fluids with a relatively low oxygen isotopic composition is a gravity driven meteoric water which underwent an intense water rock interaction the topographic relief created by the variscan tectonism could have allowed groundwater to penetrate into the deeper subsurface and to migrate towards the margin of the foreland basin non ferroan fracture filling calcites formed later during the mesozoic or tertiary low salinity meteoric waters and high salinity cacl2 nacl brines with a temperature around 50 c migrated through this fracture system along these fractures meteoric water migrated down into the subsurface and the brines could have flowed upward from the basement

curie point depth investigation of central anatolia turkey the residual aeromagnetic total field intensity anomalies in central anatolia were calculated from the regional aeromagnetic anomalies surveyed by the mineral research and exploration mta of turkey the residual aeromagnetic data were analyzed to produce curie point estimates by the method of okubo et al 1985 the curie point depth of central anatolia varies from 7 9 km and 22 6 km the shallowest curie point depths were observed around the cappadocia and erciyes volcanic complexes in central anatolia a good correlation was deduced between the curie point depths and the heat flow data measured previously which is most certainly important for the geothermal resources of the region the shallow curie point depths also correlate well with the hot spring locations in central anatolia

the north anatolian fault a new look dedicated to the memory of three pioneers ihsan ketin sirri erinc and melih tokay and a recent student aykut barka who burnt himself out in pursuit of the mysteries of the north anatolian fault abstract the north anatolian fault naf is a 1200 km long dextral strike slip fault zone that formed by progressive strain localization in a generally westerly widening right lateral keirogen in northern turkey mostly along an interface juxtaposing subduction accretion material to its south and older and stiffer continental basements to its north the naf formed approximately 13 to 11 ma ago in the east and propagated westward it reached the sea of marmara no earlier than 200 ka ago although shear related deformation in a broad zone there had already commenced in the late miocene the fault zone has a very distinct morphological expression and is seismically active since the seventeenth century it has shown cyclical seismic behavior with century long cycles beginning in the east and progressing westwa

slip distribution along the north anatolian fault associated with the large earthquakes of the period 1939 to 1967 abstract between 1939 and 1967 six large fault ruptures formed a westward migrating sequence of events along a 900 km long nearly continuous portion of the north anatolian fault for these events the 1939 erzincan 1942 niksar erbaa 1943 tosya 1944 bolu gerede 1957 abant and 1967 mudurnu valley earthquakes i have compiled a record of dextral slip which contains nearly 100 points these data indicate that the amount of slip is irregularly distributed along the 1939 to 1967 rupture zone the maximum slip 7 5 m occurred during the 1939 earthquake in the eastern 150 km of the 900 km long rupture zone dextral offsets diminish very abruptly eastward but very gradually westward the rate of westward decrease in the 1939 to 1967 offsets is only slightly greater than the rate of westward decrease of post miocene displacement along the north anatolian fault this suggests that westward decrease in slip can be expected to be a general characteristic of earthquake ruptures along the north anatolian fault in the future nevertheless within the 1939 to 1967 slip distribution there are three regions that had less slip than the neighboring regions these i interpret as possible sites of large future earthquakes one of these seismic gaps has already experienced another earthquake in 1951 and subsequent creep

constraints on fluid origins and migration velocities along the marmara main fault sea of marmara turkey using helium isotopes abstract fluids venting from the submarine portion of the marmara main fault part of the north anatolian fault system turkey were sampled in ti bottles deployed by submersible the fluids consist of mixtures of fault derived gases fault related cold seep fluids and ambient seawater these components can readily be distinguished using the isotopes of he and the he ne ratios 3he 4he ratios range between 0 03 0 1 and 4 9 0 4 ra indicating that both crustal and mantle derived sources of helium are sampled by the fault the dominant gas in all the samples analyzed is methane with the abundance of co2 below detection 2 in the mantle rich high 3he 4he fluids this is in contrast to nearly all mantle derived fluids where the c species are dominated by co2 while high ch4 co2 ratios may reflect organic or inorganic reactions within the crust which reduce mantle derived co2 to methane this is not a priori necessary we show that simple dilution of mantle fluids with methane produced within local sediments could result in the high 3he 4he methane rich gases currently emanating from the fault this observation is supported by an anticorrelation between 3he 4he and c 3he which is consistent with addition of c and 4he simultaneously to the fluids the highest 3he 4he ratios were found in the tekirdag basin at the foot of the escarpment bordering the western sea of marmara where seismic data are consistent with the presence of a fault network at depth which could provide conduits permitting deep seated fluids to rise to the surface the lack of recent volcanism or any evidence of underlying magmatism in the area along with low temperature fluids strongly suggests that the 3he rich helium in these fluids was derived from the mantle itself with the marmara main fault providing a high permeability conduit from the mantle to the surface assuming that the mantle source to the fluids originally had a 3he 4he ratio of 6 ra the minimum fluid velocities considering only vertical transport and no mixing with parentless 4he implied by the high 3he 4he ratios are of the order of 1 100 mm yr 1

seismic cycles recorded in late quaternary calcite veins geochronological geochemical and microstructural evidence southwest turkey is seismically active as a result of the hellenic subduction process in the eastern mediterranean we conducted high resolution micro sampling high precision u series dating and microchemical analysis on an extensional vein system in a tectonically active but non hydrothermal area u th age data and microscopic observations provide evidence of repeated fracturing of a previously sealed crack system followed by a new increment of veining repeated injection of veinlets suggests that the vein system was formed by the crack seal mechanism four major u th age groups for the emplacement of the vein system fall between 23 9 0 2 ka and 23 2 0 4 ka 21 7 0 4 ka and 19 2 0 2 ka 17 3 0 1 ka and 16 2 0 3 ka and at 11 8 0 2 ka stable and sr isotope geochemistry of the calcite vein samples indicates that surface water interacting with the soil cover was the major component of the groundwater system from which the extensional veins precipitated trace element and 0 isotope data of the vein system are interpreted to reflect carbonate precipitation associated with seismic cycles involving fluids with different trace element compositions and co2 contents initial carbonate precipitation during a single seismic cycle occurred from co2 dominated fluids that were degassed from the original co2 water mixture this was followed consecutively by carbonate precipitation from the remaining water which was relatively impure with higher trace element contents millimetre to submillimetre scale u series dating in conjunction with geochemistry of carbonate veins related to active tectonism offers an innovative means of constraining the absolute timing of late quaternary seismic and inter seismic events c 2010 elsevier b v all rights reserved

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

the impact of topography on isotopes in precipitation across the central anatolian plateau turkey paleoelevation reconstructions of mountain belts and orogenic plateaus based on stable isotope climate and precipitation records benefit greatly from present day calibrations that relate the fractionation of hydrogen d and oxygen 18o isotopes in precipitation to orographic rainfall here we establish a first order template of d and 18o of modern meteoric waters across the central anatolian plateau cap and its bordering pontic and taurus mountains we identify key regions in the plateau interior and along the plateau margins that have the potential to reliably record topography related paleotemperature and paleoprecipitation changes as recovered from stable isotope paleosol fossil teeth or lipid proxy data based on d and 18o data of more than 480 surface water samples from small catchments and springs we characterize moisture sources affecting the net isotopic budget of precipitation over the cap and analyze how orographic rainout and plateau aridity shape modern patterns of d and 18o in precipitation the taurus mountains bordering the cap to the south act as a major orographic barrier for transport of predominantly winter moisture and exhibit isotopic lapse rates of approximately 20 km for d and 2 9 km for 18o across an elevation range of nearly 3000 m the pontic mountains at the northern margin of the cap force perennial moisture to ascend and condensate revealing lapse rates of 19 km for d and 2 6 km for 18o the difference in the predominant moisture source for the southern and northern margins of the cap north african versus atlantic air masses is manifested in systematic north south differences in near sea level meteoric water compositions of dn s 20 permil and 18on s 3 permil in a swath across the central part of the plateau stable isotope data from the semi arid plateau interior with rainfall as low as 300 to 500 mm yr and mean summer temperatures attaining 23 c provide clear evidence for an evaporative regime that drastically affects surface water and runoff compositions and results in a local meteoric water line for the plateau interior that follows d 4 0 18o 29 3 strongly evaporitic conditions contrast rainfall patterns along the plateau margins including their immediate leeward flanks where d and 18o elevation relationships are reliable predictors of modern topography

isotopic evidence for the infiltration of mantle and metamorphic co2 h2o fluids from below in faulted rocks from the san andreas fault system to characterize the origin of the fluids involved in the san andreas fault saf system we carried out an isotope study of exhumed faulted rocks from deformation zones vein fillings and their hosts and the fluid inclusions associated with these materials samples were collected from segments along the saf system selected to provide a depth profile from upper to lower crust in all 75 samples from various structures and lithologies from 13 localities were analyzed for noble gas carbon and oxygen isotope compositions fluid inclusions exhibit helium isotope ratios 3he 4he of 0 1 2 5 times the ratio in air indicating that past fluids percolating through the saf system contained mantle helium contributions of at least 35 similar to what has been measured in present day ground waters associated with the fault kennedy et al 1997 calcite is the predominant vein mineral and is a common accessory mineral in deformation zones a systematic variation of c and o isotope compositions of carbonates from veins deformation zones and their hosts suggests percolation by external fluids of similar compositions and origin with the amount of fluid infiltration increasing from host rocks to vein to deformation zones the isotopic trend observed for carbonates in veins and deformation zones follows that shown by carbonates in host limestones marbles and other host rocks increasing with increasing contribution of deep metamorphic crustal volatiles at each crustal level the composition of the infiltrating fluids is thus buffered by deeper metamorphic sources a negative correlation between calcite 13c and fluid inclusion 3he 4he is consistent with a mantle origin for a fraction of the infiltrating co2 noble gas and stable isotope systematics show consistent evidence for the involvement of mantle derived fluids combined with infiltration of deep metamorphic h2o and co2 in faulting supporting the involvement of deep fluids percolating through and perhaps weakening the fault zone there is no clear evidence for a significant contribution from meteoric water except for overprinting related to late weathering

surface rupture and slip distribution of the 12 november 1999 duzce earthquake m 7 1 north anatolian fault bolu turkey the 12 november 1999 earthquake m 7 1 occurred on the duzce fault a splay of the north anatolian fault in the bolu basin approximately three months after the 17 august 1999 m 7 4 earthquake the surface rupture was 40 km long and the maximum right lateral offset was 500 5 cm averaging 300 cm the 9 km of the westernmost part of the rupture along the southern margin of the eften lake had a 350 cm maximum vertical displacement normal faulting some of which was already ruptured during the 17 august 1999 event with few tens of centimeters the surface rupture has a generally simple narrow deformation zone of 0 5 5 m however in some places it widens to 50 m transtensional and transpressional structures were observed within releasing and restraining step over areas respectively the larger dextral offsets on some streams indicate previous events the dextral slip measurements along the rupture reflect a symmetric distribution the eastern connection of this rupture zone with the main trace of north anatolian fault remains unclear because the bakacak and elmalik fault which are connecting faults had no surface rupture manuscript received 14 november 2000

seawater ph and isotopic paleotemperatures of cretaceous oceans abstract stable oxygen isotope ratios 18 o of foraminifera are widely used to reconstruct the climatic history of earth it is well known that temperature reconstructions based on 18 o are complicated by factors such as the unknown isotopic composition of the ocean in addition recent experimental and theoretical work has shown that the seawater ph has a marked effect on the 18 o of foraminifera here i employ this effect to demonstrate that reconstructions based on 18 o of foraminifera may underestimate sea surface temperatures in the geological past ocean surface temperatures for the mid cretaceous are estimated to have been 2 3 5 c higher than previously thought

oxygen isotopes in meteoric calcite cements as indicators of continental paleoclimate because meteoric water 18 o values decrease with decreasing ambient temperature and increasing latitude 18 o values of meteoric calcite cement should exhibit a similar relation with paleolatitude and be an indicator of continental paleotemperatures to test this we compiled isotopic and paleolatitude data for 20 meteoric cements and nine speleothems ranging in age from devonian to modern and in paleolatitude from 3 5 to 83 mean 18 o values for meteoric cements and speleothems both show the same negative correlation with paleolatitude the 18 o vs latitude trend for these carbonates is almost identical to that predicted for modern inland environments but differs from the trend for coastal environments this suggests that the ground water controlling the ultimate composition of meteoric cement is derived predominantly from inland recharge if it is assumed that the modern meteoric water 18 o vs temperature relation is valid for the past and that insignificant evaporation occurred prior to carbonate precipitation then coastal and inland paleotemperatures can be calculated from the 18 o values of meteoric calcite 18 o mcl and seawater 18 o sw by using the equations t coastal 13 3 32 6 0 231 0 0613 18 o mcl 18 o sw and t inland 17 8 16 2 0 572 0 1233 18 o mcl 18 o sw where t is temperature in c calcite precipitated from coastal meteoric water at temperatures between 0 and 25 c will exhibit a narrow range in 18 o 6 to 4 where 18 o sw 0 the 18 o of calcite precipitated from inland meteoric water will be sensitive to paleotemperature ranging from 14 to 5 where 18 o sw 0 for temperatures of 0 to 25 c

the north anatolian fault zone and the role of fluids in seismogenic deformation a study of the north anatolian fault zone turkey in dicates significant spatial variations of deformation mechanisms and fluid flow along and across a major active strike slip fault brittle deformation and later dissolution are mostly localized within the fault core whereas crystal plastic deformation and diffusive mass transfer are more widely distributed the fault underwent a three stage development i repeated episodes of frictional failure pressure solution fluid migration and subsequent healing cataclasites and veins were formed during this stage we propose that the episodic events are associated with open and closed fluid systems during seismogenic cycles the progressive brittle failure led to stage ii a more open system with increasing dilation connected with dissolution the dramatic increase of dissolution processes terminated the episodic character of deformation and marked the beginning of a stage iii mostly characterized by diagenetic processes the fluid regime is now an op

tectonic evolution of the ganos segment of the north anatolian fault nw turkey we analyzed the paleostress field ongoing deformation meso to micro scale faulting cataclasis fault rock alteration and veining within turbidite and limestone sequences at the ganos fault which represent a major branch of the north anatolian fault zone in nw turkey fault damage was found to occur across a several kilometers wide zone effects of faulting are shown by localized subsidiary brittle faults and fault rock alteration in the turbidites as well as fault breccia formation in the limestone sequence microseismicity along the ganos fault cluster at two locations the more pronounced being located offshore at a fault bend associated with a change from a transpressional to a transtensional regime kinematic analysis reveals a dextral strike slip regime with components of normal and thrust faulting along strike paleostress orientation at the ganos fault is rather uniform deformation mechanisms and fluid inclusion data from quartz and calcite veins suggest that fault related quartz veins were formed at temperatures between 170 and 250 c and pressures between 40 and 120 mpa fault related calcite vein

palaeomagnetic study of block rotations in the niksar overlap region of the north anatolian fault zone central turkey abstract this palaeomagnetic study investigates crustal deformation within and adjacent to the niksar overlap area of the north anatolian fault zone nafz in central east turkey the studied rock formations comprise 1 red limestones of late cretaceous age 3 sites 2 mafic lavas of eocene age on the north side 13 sites and south side 9 sites of the nafz and 3 volcanic rocks of pliocene quaternary age from the niksar pull apart basin within the nafz 8 sites comparisons with reference palaeofield directions computed from apparent polar wander paths of the eurasian and afro arabian plates identify two scales of regional and local tectonic rotation 1 1 a pre tilting remanence in the eocene volcanic rocks south of the nafz d i 144 1 47 5 95 7 6 is interpreted to reflect counterclockwise rotation by 30 40 from the reference palaeofields contemporaneous volcanic rocks from the north side of the nafz have the same reverse polarity recorded in pre tilting magnetisations the remanence is also rotated counterclockwise d i 152 4 42 5 95 11 3 but by about 8 less than the volcanics on the south side of the nafz hence similar amounts of rotation are observed on both sides of the nafz and are interpreted to reflect motions during the pre middle miocene collisional history in this sector of the pontides no distributed clockwise rotations anticipated from subsequent dextral motion along the nafz intracontinental transform are observed the slightly larger anticlockwise rotation found on the south side of the nafz probably records relative rotation of en echelon wedges by continental escape during post middle miocene strike slip along the transform 2 2 within the narrow zone of intense deformation along the nafz cretaceous limestones appear to be rotated clockwise by dextral strike slip motion whilst plio quaternary lavas within a fault bounded block in the overlap region associated with the niksar pull apart basin have magnetisations consistently directed 240 270 e magnetic inclinations are not diagnostic of polarity but both polarity solutions identify rapid clockwise rotation at rates in excess of 50 m y a normal polarity solution is favoured and implies that a block ca 5 km across has undergone a strike slip displacement of around 12 km within the nafz during the last polarity chron cretaceous eocene palaeolatitudes are closer to those predicted from eurasia than afro arabia but a study of older rocks is required to resolve affinities of this sector of the anatolian block theoretical models of crustal deformation across intracontinental transforms obeying power law behaviour and treating the lithosphere as a viscous medium predict that distributed clockwise rotations should be observed about as broad across the nafz these rotations are not observed instead intense clockwise rotation is confined to a narrow zone close to the major fault break the concentration of historic seismic activity here also implies that the bulk of the dextral motion between the eurasian plate and the anatolian block is accommodated by slip along faults close and parallel to the main trace of the nafz

control of mechanical stratigraphy on bed restricted jointing and normal faulting eagle ford formation south central texas outcrops of the middle eagle ford formation in south central texas reveal well developed joint networks in subhorizontal competent carbonate chalk beds and less well developed networks in interlayered incompetent calcareous mudrock beds northeast striking bed perpendicular joints in competent beds have the longest trace lengths and are abutted by northwest striking joints all observed joints terminate vertically in incompetent beds normal faults are common but less abundant than joints dominantly dip north northwest or southeast and are abutted by the joint sets and thus predated jointing the faults cut multiple competent and incompetent beds providing vertical connectivity across mechanical layering products of hybrid and shear failure the dip of these faults is steep through competent beds and moderate through incompetent beds resulting in refracted fault profiles with dilation and calcite precipitation along steep segments fluid inclusions in fault zone calcite commonly contain liquid hydrocarbons rare two phase fluid inclusions homogenized between about 1 40 and 58 c and 2 90 and 100 c suggesting trapping of aqueous fluids at elevated temperatures and depths on the order of 2 km 6562 ft fluid inclusion and stable isotope geochemistry analyses suggest that faults transmitted externally derived fluids these faults likely formed at depths equivalent to portions of the present day oil and gas production from the eagle ford play in south texas faults connect across layering and provide pathways for vertical fluid movement within the eagle ford formation in contrast to vertically restricted joints that produce bed parallel fracture permeability these observations elucidate natural fractures and induced hydraulic fracturing within the eagle ford formation

geochemistry and mineralogy of travertine deposits of the sw flank of mt etna italy relationships with past volcanic and degassing activity abstract travertine deposits outcropping in the lower sw flank of mt etna were studied for their mapping as well as for their chemical mineralogical and isotopic compositions these deposits are dated to about 24 to 5 ka in the adrano area located at the western limit of the study area in this area travertines show high mg contents and are composed mostly of dolomite thus apparently ruling out any primary deposition in favour of a diagenetic origin travertines outcropping near paterno in the east part of the study area should be younger than 18 ka those located to the ssw of paterno paterno diga show high sr contents and aragonite as dominant mineralogical phase thus suggesting primary deposition those located to the w of paterno paterno simeto stazione are instead poor both in mg and in sr and show calcite as dominant phase carbon isotope composition of travertines indicates a magmatic origin of co2 that formed them based on the estimated volume of travertines between 10 and 20 gg a of co2 were involved in their formation the time span of travertine formation coincided with the eruptive cycles of ellittico and the first part of mongibello which were probably characterised by a greater amount of co2 transported through groundwater circulation widespread travertine deposition probably ceased after the opening of the valle del bove depression that modified the volcanologic and hydrologic conditions in the summit crater area

quantifying submarine fluid seep activity along the north anatolian fault zone in the sea of marmara abstract the sea of marmara presents the rare case where active seafloor venting sites are found on the surface trace of a major plate boundary fault the north anatolian fault zone the objective of the 2007 marnaut project was to quantify the level of activity of these venting sites and the source of the fluids emitted with the goal of understanding the processes involved and setting a baseline for long term studies of the relationship between seismic activity and fluid migration expulsion processes sites for flow meter and fluid sampler deployment and coring included basin bounding transtensional faults and strike slip faults cutting through the topographic highs significant fluid flow appears to be primarily an episodic phenomenon at all sites with background rates on the order of mm yr to cm yr except at or very near rare focused vents basin bounding faults expel primarily shallow sourced fluid with a strong influence of brackish pleistocene lake marmara water with the notable exception of the main active fault along the northern edge of the cinarcik basin expulsion sites where the main fault crosses topographic highs are more complex with evidence for deep sourced fluids including thermogenic gas one site on the western high displayed two mound structures that appear to be chemoherms atop a deep seated fluid conduit the fluids being expelled are brines with an exotic fluid chemistry along with thermogenic gas and oil our work shows that submerged continental transform plate boundaries can be hydrologically active and exhibit a diversity of sources and processes

crustal structure of the north anatolian and east anatolian fault systems from magnetotelluric data abstract magnetotelluric mt studies can map subsurface resistivity structure and have located zones of low resistivity high conductivity within major strike slip fault zones worldwide which have been interpreted as regions of elevated fluid content this study describes mt data from the eastern part of the north anatolian and the east anatolian fault systems nafs and eafs and presents the results of the first mt studies of these faults the inversion of the mt data produced 2 d resistivity models which showed that both fault systems are underlain by a broad low resistivity zone that extended into the lower crust however the resistivity beneath the east anatolian fault system was much lower than beneath the eastern part of the north anatolian fault system these conductors begin at a depth of 10 km not at the surface as on the central san andreas fault safs this difference is interpreted as being due to the fact that the eafs and nafs are young fault systems characterized in the upper crust by multiple fault traces as opposed to the safs that has evolved into a single through going fault different stages of the seismic cycle may also influence the resistivity structure although this is difficult to constrain without knowledge of time variations in resistivity structure at each location

geochemistry and geochronology of meta igneous rocks from the tokat massif north central turkey implications for tethyan reconstructions located in the eastern pontides of the sakarya zone in north central turkey the tokat massif records the closure of both the paleo tethyan karakaya complex and neo tethyan ocean basins meta igneous samples collected from the region were studied to determine their sources and ages we find significant geochemical differences between metagabbros of the karakaya and neo tethyan units in terms of their trace elements neo tethyan rocks are consistent with generation in an island arc setting whereas karakaya assemblages were likely generated in an oceanic spreading center environment karakaya metagabbros also contain glaucophane consistent with subduction subsequent to formation small 2 50 m zircon and baddeleyite grains from four karakaya metagabbros were dated in thin section using an ion microprobe the results demonstrate the reliability of the method to directly constrain the tectonomagmatic history of these types of assemblages the rocks yield late permian early triassic 238u 206pb crystallization ages of 258 14 ma 1 zircon and 254 8 ma 1 baddeleyite and an early cretaceous minimum metamorphic age of 137 8 ma 1 zircon some zircon grains and baddeleyite grains with zircon overgrowths yield early to middle jurassic ages here we present a model in which metamorphism and deformation in this region occurred during northward subduction and closure of a paleo tethyan ocean basin and accretion of the karakaya units to the laurasian continental margin this was followed by the onset of closure of the neo tethys during the campanian paleocene and accretion of island arc units to the tokat region

curie point depth map of turkey summary a curie point isotherm map of the whole of turkey has been prepared from aeromagnetic data by means of a spectral analysis technique the most characteristic signature of this map is that the shallow depths generally correlated with the young volcanic rocks and the thinned crustal thicknesses in the west reveal geothermal fields and several hot springs the orogenic pontide belt of the black sea region in the north the western taurus belt in the south and some high plateaus in eastern turkey show that the deepest curie isotherm depths range between 20 and 29 km depth contour lines elongating in an almost e w direction are due to the overlapping percentage of adjacent data blocks of 50 per cent in the e w direction and to magnetic anomalies trending in the e w direction curie isotherm depths are in the range 6 to 10 km in the aegean region and are characterized by e w and ne sw trending graben structures as expected since the region has crustal thinning and many hot springs and geothermal fields these imply the existence of shallow heat sources that could be utilized for electricity heating of towns and cities greenhouse and health purposes

platform slope transition during rifting the mid cretaceous succession of the amasya region northern anatolia turkey abstract the mid cretaceous rocks of the amasya region north central anatolia record the geological processes that occurred during the break up of the eastern pontide carbonate platform which existed from mid jurassic to early cretaceous the mid cretaceous sedimentary rocks consists of benthic foraminiferal packstones grainstones of ferhatkaya formation and limestone breccias turbidites pelagic foraminiferal wackestones packstones and radiolarites of sarilar formation corresponding to platform and slope apron environments respectively the lithological development of these units was controlled mainly by active subsidence due to block faulting affecting the eastern pontide carbonate platform due to the break up of the platform during late barremian early aptian times slope and basin sediments were deposited on the deeper parts of the platform re deposited sediments such as limestone breccias and calciturbidites document the infilling of asymmetric grabens during the mid cretaceous rifting phase re deposited sequences which were formed as a fault slope apron sedimentary prism related to this rifting were deposited during thinning and fining upward megacycles a typical megacycle commences with breccias deposited at the base of a fault scarp association in addition the upper part of the platform carbonates ferhatkaya formation includes neptunian dykes composed of red mudstones with pelagic fossils indicating a period of extension

regional and temporal variations in co2 3he 3he 4he and δ13c along the north anatolian fault zone turkey abstract new he and c relative abundance isotope and concentration results from nine geothermal locations situated along an 800 km transect of the north anatolian fault zone nafz turkey that were monitored during the period november 2001 november 2004 are reported the geothermal waters were collected every 3 6 months to study possible links between temporal geochemical variations and seismic activity along the nafz at the nine sample locations the he isotope ratios range from 0 24 to 2 3 r a 13 c values range from 4 5 to 5 8 and co 2 3 he ratios range from 5 10 9 to 5 10 14 the following geochemical observations are noted 1 the highest 3 he 4 he ratios are found near the galatean volcanic region in the central section of the nafz 2 at each of the nine sample locations the 3 he 4 he ratios are generally constant however co 2 3 he ratios and he contents both show one order of magnitude variability and 13 c values show up to 4 variability and 3 at all locations except resadiye 13 c values show positive correlations with co 2 contents the results indicate that at least three processes are necessary to account for the geochemical variations 1 binary mixing between crustal and mantle derived volatiles can explain the general characteristics of 3 he 4 he ratios 13 c values and co 2 3 he ratios at the nine sample locations 2 preferential degassing of he from the geothermal waters is responsible for variations in co 2 3 he values and he contents at each sample location and 3 co 2 dissolution followed by calcite precipitation is responsible for variations in co 2 contents and 13 c values at most locations for each of the geochemical parameters anomalies are defined in the temporal record by values that fall outside two standard deviations of average values at each specific location geochemical anomalies that may be related to seismic activity are recorded on june 28 2004 at yalova where a m 4 2 earthquake occurred 43 days earlier at 15 km distance from the sample location and on april 7 2003 at efteni where a m 4 0 earthquake occurred 44 days later at a distance of 12 km at both locations the sampling periods containing geochemical anomalies were preceded by an increase in m 3 earthquakes occurring within 60 days and less than 40 km distance

the use of a combined structural stable isotope and fluid inclusion study to constrain the kinematic history at the northern variscan front zone bettrechies northern france abstract a detailed structural stable isotope and fluid inclusion study of distinct vein generations has been performed in a kilometre scale syncline to correlate the temperature pressure conditions of vein formation with specific deformation episodes the structural relationship of the veins with cleavage folds faults and with one another allows the identification of pre syn and post variscan carbonate vein generations the stable isotope composition of the vein calcites and dolomites is very similar to that of the surrounding limestones and dolostones respectively this indicates that the cements were precipitated from fluids buffered by the host rock and implies that the temperature pressure characteristics of the fluids reflect the thermal history of the deformation history within the syncline microthermometric data of primary fluid inclusions were used to estimate the temperature pressure conditions at precipitation time and thus of the deformation pressure corrected trapping temperatures for the veins show a temperature evolution from pre variscan 310 c to variscan 260 200 c and post variscan 75 c this evolution indicates that the syncline developed not at a specific depth but rather as an active progressive deformation process during transport along the northern variscan thrust front

strain response and re equilibration of ch4 rich synthetic aqueous fluid inclusions in calcite during pressure drops abstract aqueous fluids in sedimentary basins often contain dissolved methane particularly in petroleum environments pvtx pressure volume temperature composition reconstructions performed using fluid inclusion data are largely based on the assumption that inclusions do not change from the time of trapping until the present many authors however consider that fluid inclusions can re equilibrate particularly in fragile minerals like calcite in order to understand this re equilibration phenomenon in the metamorphic domain previous experiments have been performed under high pt conditions but few have been performed at low to medium pt conditions such as those associated with sedimentary burial diagenesis and no previous studies have examined ch 4 bearing aqueous inclusions in calcite an experimental study of the preservation modification of ch 4 rich synthetic fluid inclusions in calcite during isothermal decompression was conducted an autoclave was used for accurate ptx control allowing equilibrium between liquid and vapour in the ch 4 h 2 o system ptx conditions were maintained at four stages of decreasing pressure with each stage held for 7 days to simulate an isothermal pressure drop in order of decreasing pressure the pressure temperature conditions monitored were 276 10 bar at 180 7 c 176 10 bar at 180 7 c 76 10 bar at 180 7 c and 10 3 bar at 180 15 c at the end of the experiment the calcite was recovered and analyzed by microthermometry and raman microspectroscopy for ptx reconstruction a careful procedure was adopted to limit re equilibration of inclusions during analytical procedures four types of inclusion shapes and four types of strain patterns were differentiated classification of the petrographic strain patterns was carried out these strain patterns were associated with inclusion stretching and or leakage regarding ch 4 t h and p h compared to experimental conditions factors controlling the preservation or acquisition of strain patterns included the initial shape and size of the inclusion and the pressure differential p between the confining pressure p cf and the internal pressure p i within the inclusion most fluid inclusions seemed to be trapped during the first 7 days of the experiment although few 4 of these preserved the initial pt conditions of 276 10 bar whereas 8 preserved the second and third run of pt conditions overall the majority of inclusions 88 did not reflect accurately the ptx trapping conditions a petrographic guide to the inclusions is presented here that allows strain identification for pvt reconstructions re equilibration patterns and evidence for preferential methane leakage from aqueous inclusions in calcite are important findings revealed by this study and may be useful for the reconstruction of post trapping events in investigations of natural samples and in other experiments using synthetic inclusions in calcite

middle pleistocene extinction process of pull apart basins along the north anatolian fault zone abstract numerous basins that present in northern turkey formed in plio quaternary period by the strike slip tectonics of the north anatolian fault zone these pull apart basins isolated from their surrounding topographies by major scarps of faults along their margins that mapped as active faults but the mapped recent traces in the pull apart basins are in disagreement about these marginal faults and commonly characterized by the faults that pass through basin floors in the cases of surface rupturings in great earthquakes during the last century these faults have migrated from the basin rims to the center of the basins in agreement with the extinction model of pull apart basins here we review observations about numerous basins along the north anatolian fault zone to show that the migration of these faults in middle pleistocene related with the maturity of basins through their evolution

tectonic evolution of the niksar and tasova erbaa pull apart basins north anatolian fault zone their significance for the motion of the anatolian block abstract the tasova erbaa and niksar basins are two adjacent pull apart basins along the north anatolian fault zone nafz within the tasova erbaa basin sedimentary lithofacies of the upper pontus formation plio pleistocene are asymmetrically distributed with laterally derived alluvial fans coarse braid plain deposits and axial braided stream deposits dominating the northern and western parts of the basin the basin has gently dipping sediments locally affected by pervasive extensional t faulting isolated compressional structures are associated with master faults deformation zone width 500 m pervasive extensional faults t and r and late stage pdz parallel compressional faults are also present an additional set of extensional faults trends perpendicular to the pdz accommodating secondary pull apart stretching within the basin the distribution of sedimentary facies and structural styles is consistent with that predicted by models for pull apart basins the adjacent niksar basin is an active pull apart basin possibly as young as 0 5 1 ma its modern drainage and sedimentary facies are symmetrically arranged adding the lengths of the tasova erbaa and niksar basin suggests 80 km total displacement along the north anatolian fault which is consistent with seymen itu ph d thesis 1975 sengor j geol soc 136 1979 269 282 and armijo et al tectonophysics 243 1999 135 154 who observed about 85 5 km total displacement along the north anatolian fault the change in course of the north anatolian fault marked by the formation of the niksar ezinepazari segment and this new geometry suggest that the anatolian block is rotating anticlockwise by having two separate poles one located near damascus and the other occurring north of the sinai peninsula this change may also mark the transfer of the anatolian triple junction from erzincan to karliova about 1 ma ago furthermore it appears that while the fault shortcuts the older basin a new generation of pull apart basins is formed due to changes of boundary conditions along the fault zone

late cenozoic tectonics and volcanism along the north anatolian fault new structural and geochemical data abstract different types of volcanic activity have developed along the north anatolian fault zone naf in turkey detailed analysis of satellite images and digital elevation models dems and field observations have been made in order to understand the tectonics and the distribution of volcanic vents in the anatolian block some faults are oblique to the naf and delimit extensional escape wedges vents rooted on open tension fractures show that emplacement of the volcanism is related to tensional fracturing of the anatolian continental block which we attribute to the onset of free borders in the south and west along the naf earliest extension 1 is directed s to ssw and the latest 2 towards w to wsw parallel to the sinistral slip along the naf major and trace element geochemical data indicate that the dominant calc alkaline rocks are associated with various alkaline lavas k ar ages of the volcanics range from 22 to 8 5 ma in galatia massif 900 to 100 ka in niksar and 3 to 12 ka in erzincan isotopic and trace element data are interpreted as reflecting a dominantly lithospheric mantle source slightly mixed with asthenospheric liquids most magmas were fractionated and contaminated by continental crust during their ascent 1 and 2 tectono volcanic events have propagated through time and space from west to east the 1 extension is late oligocene in the galatia massif late miocene in niksar and late pliocene in erzincan the 2 extension and strike slip event along the naf began in the late miocene in the galatia massif early pliocene in niksar and quaternary in erzincan signature from an asthenospheric source in the second event in the three regions suggests that an ancient suture zone galatia massif and or the lithospheric naf transform niksar and erzincan have served to channel small quantities of asthenospheric melts existing at the base of the lithosphere

geochemical monitoring of geothermal waters 2002 2004 along the north anatolian fault zone turkey spatial and temporal variations and relationship to seismic activity a total of nine geothermal fields located along an 800 km long e w transect of the north anatolian fault zone nafz turkey were monitored for three years 2002 2004 inclusive 3 sampling periods per year to investigate any possible relationship between seismic activity and temporal variations in the chemistry and isotope characteristics of waters in the fields the geothermal fields monitored in the study were from west to east yalova efteni bolu mudurnu seben kursunlu cankiri hamamozu gozlek and resadiye the chemical major anion cation contents and isotopic 18o 16o d h 3h compositions of hot and cold waters of the geothermal sites were determined in order to both characterize the chemical nature of the individual fields and identify possible temporal variations associated with localized seismic activity the geothermal waters associated with the nafz are dominantly na hco3 whereas the cold waters are of the ca hco3 type the oxygen and hydrogen isotope compositions reveal that the hot waters are meteoric in origin as are their cold water counterparts however the lower 18o d and 3h contents of the hot waters point to the fact that they are older than the cold waters and that their host aquifers are recharged from higher altitudes with virtually no input from recent post bomb precipitation although no major earthquakes e g with m 5 were recorded along the nafz during the course of the monitoring period variations in the chemical and isotopic compositions of some waters were observed indeed the timing of the chemical isotopic changes seems to correlate with the occurrence of seismic activity of moderate magnitude 3 m 5 close to the sampling sites in this respect cl 3h and ca seem to be the most sensitive tracers of seismically induced crustal perturbations and the yalova and efteni fields appear to be the key localities where the effects of seismic activity on the geothermal fluids are most pronounced over the monitoring period the present study has produced a baseline database for future studies directed at characterizing the effects of moderate major earthquakes on the composition of geothermal waters along the nafz future work involving longer monitoring periods with more frequent sampling intervals should lead to a better understanding of the underlying mechanism s producing the observed chemical and isotopic variations

adjacent releases of mantle helium and soil co2 from active faults observations from the marmara region of the north anatolian fault zone turkey volatile releases in terms of co2 efflux and noble gas of mantle origin are investigated in the marmara region of the seismically active north anatolian fault naf zone a total of 180 co2 efflux measurements 1 to 309 g m 2d 1 were carried out along four transects across the naf spatial variability of surface co2 effluxes was higher at faulted sites relative to comparable background areas the 13c values of soil co2 are 24 0 to 15 6 without correlation with co2 efflux values which suggest that co2 efflux anomaly is caused by fault related biogenic gas flow furthermore 36 gas and water samples from spring sites were investigated for 3he 4he ratios which resulted in a range from 0 26 r ra to 4 22 r ra large mantle helium contributions were observed from several sources along the naf the high co2 efflux sector on the gazikoy saros fault along the naf coincides with the area of high mantle helium flux this shows that fault zones play an important role both in transferring mantle helium to the surface and in causing fault related biogenic gas flow

fault deformation mechanisms and fault rocks in micritic limestones examples from corinth rift normal faults abstract a multidisciplinary study investigates the influence of different parameters on fault rock architecture development along normal faults affecting non porous carbonates of the corinth rift southern margin here some fault systems cut the same carbonate unit pindus and the gradual and fast uplift since the initiation of the rift led to the exhumation of deep parts of the older faults this exceptional context allows superficial active fault zones and old exhumed fault zones to be compared our approach includes field studies micro structural optical microscope and cathodoluminescence geochemical analyses 13 c 18 o trace elements and fluid inclusions microthermometry of calcite sin kinematic cements our main results in a depth window ranging from 0 m to about 2500 m are i all cements precipitated from meteoric fluids in a close or open circulation system depending on depth ii depth in terms of p t condition determines the development of some structures and their sealing iii lithology marly levels influences the type of structures and its cohesive non cohesive nature iv early distributed rather than final total displacement along the main fault plane is the responsible for the fault zone architecture v petrophysical properties of each fault zone depend on the variable combination of these factors