middle pleistocene bivalves of the iznik lake basin eastern marmara nw turkey and a new paleobiogeographical approach iznik lake is a tectonically originated basin mainly controlled by the e w trending middle strand of the north anatolian fault naf system pleistocene sediments occurring in front of the faults are well exposed both in the northern and in the southern shorelines of the basin in this study two endemic brackish water bivalve species didacna subpyramidata pravoslavkev 1939 and didacna nov sp were found in the oldest terrace of the northern pleistocene sequence having characterized morphology these species serve as stratigraphic indicators in the regional pleistocene stratigraphy of the ponto caspian region and thus are well correlated to the assemblages of the early khazarian subhorizon middle pleistocene hence these data demonstrate that the early khazarian brackish water sea covered the study area additionally a model for the formation of the basin is proposed the iznik lake basin was a gulf of the former marmara sea in the early khazarian connecting the marmara to the black sea and the caspian sea the subsequent regional prograding uplifts main dextral strike slip fault and many normal faults of the naf zone cut off the marine connections to the basin leading to its present location and topographic level

sequence stratigraphy tectonics and depositional history in eastern thrace basin nw turkey abstract the eastern thrace basin forms the eastern portion of the turkish thrace basin in nw turkey the pre tertiary crystalline basement shows platform and deep basin depositional morphology which results in facies pattern and thickness distribution localization during the early stages of basin development in middle to late eocene time normal fault controlled early and lateral reverse fault controlled later stage tectonic events characterize basin geometry and the present topography respectively the early stage normal faulting caused subsidence and sediment accumulation in the late eocene and early oligocene while later stage tectonic events caused intense deformation and structuration in the early to middle miocene as a result southeastern and northern regions were folded or uplifted and deeply eroded outcrop well log core and reflection seismic studies reveal that the sedimentary succession can be subdivided into five characteristic depositional sequences bounded at their base by unconformities these unconformities were dated using paleontological data the sequence boundaries underlying consecutively sequences 1 2 3 and 5 were dated at 39 5 36 30 and 25 5 ma from older to young in order of succession corresponding to the major erosional breaks between the middle and upper eocene the upper eocene and the lower oligocene the lower and upper oligocene and the upper oligocene and the lower miocene the sequence boundary underlying sequence 4 was determined to lie within the late oligocene succession and as an age designation could not be assigned it was termed intra sequence boundary isb the first two sequences correspond to relative sea level rises and a normal fault controlled tectonism coincides with them reefal carbonates coarse grained clastics and marine shales with abundant volcanic flows or layers represent the sedimentary facies of these two early sequences the third and fourth sequences correspond to either a decreased relative rise of sea level or a relative still stand of sea level and a sediment induced subsidence related to thermal relaxation provides accommodation prograding delta sediments of varying extent constitute the sedimentary packages of these two sequences the depositional sequence 5 which makes up the uppermost part of the sedimentary succession in the basin corresponds to a relative sea level fall and a tectonic style shaped by lateral and inversion faulting characterizes this period nonmarine alluvial fan fluvial channel and various lagoonal deposits constitute the sedimentary facies of this last sequence porous reefal limestones and shallow marine beach sandstones of sequence 1 and deltaic sandstones of sequences 3 and 4 provide good reservoir rocks for the hydrocarbons produced in the study area the marine shales and marls of the second and the third sequences provide good source rocks as they are rich in disseminated organic matter content although the non marine alluvial and fluvial channel deposits of sequence 5 are good reservoirs they lack effective seals the time interval in which sequence 5 was deposited represents a period of major structural and trap development in the basin

coal characteristics palynology and palaeoenvironmental interpretation of the yenikoy coal of late oligocene age in the thrace basin nw turkey abstract the yenikoy coal field is located in a narrow area between the black sea coast and the istranca standrja mountain in the thrace basin the aims of this study are to characterize coal petrographical mineralogical palynological geochemical and sedimentological properties of the yenikoy coal deposit and to reconstruct palaeoenvironmental conditions during peat accumulation a total of 9 coal samples collected from the coal seam section are almost entirely composed of xylite rich lithotype and are characterized by low ash yield 7 9 21 1 average 13 6 on dry basis and high total s contents 1 0 3 7 average 2 2 on dry basis the macroscopic features maceral composition and coal facies suggest that the peat was accumulated under mesotrophic anoxic conditions and the peat forming vegetation consisted mainly of arboreal species e g cupressaceae ulmus carya zelkova alnus pterocarya and quercus the low hi values of the analysed samples are presumably related to presence of xylite rich lithotype rather than the dominance of herbaceous plant and or low preservation of organic matter in the palaeomire even though relatively b enrichments high total s contents and weak anomalies of some rey e g y ce and gd in the analysed samples could refer possible sea water influence into palaeomire in the study area during late oligocene the sedimentological and palynological freshwater algaes pediastrum spirogyra and mougeotia data that indicate the palaeomire was located within a delta plain environment where small freshwater lakes and or ponds developed the statistical analysis and sem edx data show the vast majority of elements in the analysed coal samples have inorganic affinity the major elements al k and enriched elements like b v cr hg and u seem to be affiliated with aluminosilicate minerals whereas fe ni and as have probably sulphide affinity the detrital presences of apatite crystals as detected by sem edx analysis indicate that rey have mainly phosphate affinity in the analysed samples vertical distributions of the elements and ash yields suggest that the detrital input ratio was changeable and controlled some elemental enrichment during peat accumulation these variations could be related to development of and fluvial conditions in the study area which interrupted peat accumulation several times during late oligocene

seismic reflections from the mantle represent relict subduction zones within the continental lithosphere in many areas of the world the continental lithospheric upper mantle contains bright continuous regionally extensive seismic reflectors despite the increasingly common observation of such mantle reflectors on deep seismic reflection profiles their significance and geologic origin remain obscure we report results from a series of seismic experiments acquired across two of the brightest of these reflectors and provide new constraints upon the composition and thickness of the reflecting region these new seismic data reveal regionally extensive dipping and subhorizonal slabs of high velocity 8 4 km s high density 3500 kg m 3 material several kilometres 2 km thick entrained within otherwise unremarkable upper mantle the geometry physical properties and geologic setting of these mantle reflectors suggest that they represent fragments of eclogitic oceanic crust a relict of pre caledonian oceanic subduction now preserved within the lower continental lithosphere such relict subduction zones appear to be widespread within the continental lithosphere and to exert an important influence upon the location and style of subsequent continental deformation

fission track evidence for late oligocene and mid miocene activity along the north anatolian fault in south western thrace apatite fission track ft analyses of sandstone samples collected across the trace of the ganos segment of the north anatolian fault naf in south western thrace turkey indicate that a significant structural discontinuity was in existence at least by the latest oligocene such discontinuity had a complex kinematic history as exhumation south of it occurred during the latest oligocene and north of it during the mid miocene our data imply that early pliocene westward propagation of the naf in the marmara region followed a pre existing structural discontinuity such discontinuity could be related to the development of the intra pontide suture marking the terminal closure of the intra pontide ocean during the oligocene

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

palaeogeographical evolution of the thrace neogene basin and the tethys paratethys relations at northwestern turkey thrace abstract the thrace neogene basin situated in northwestern turkey was initiated by strike slip faulting that was active from the early miocene until the end of the pliocene during the early miocene it began to form under the control of the thrace eskisehir fault zone initiated by continental collision in northwestern anatolia late oligocene early miocene during the late early miocene the basin was a site of mainly fluviatile and limnic sedimentation to the west and marine sedimentation via the paratethyan transgression in the north with the onset of the middle miocene the thrace block started to rotate in a counterclockwise sense and escaped westward with respect to the strandja istanbul block owing to rejuvenation of fossil fault systems within it in this period warm marine conditions were also established around the gulf of saros through a mediterranean originated transgression during the middle late miocene fluviatile and limnic conditions were created over the western thrace by the westerly propagation of the thrace eskisehir fault zone one of the principal results of the early middle miocene tectonics is the tilting of the strandja istanbul block to the south severing the tethys and the paratethys during the latest miocene early pliocene period the thrace eskisehir fault zone was deactivated because of the evolution of the north anatolian fault zone to the south the resurrected ganos fault zone situated on the dissected fossil suture zone in the sea of marmara also joined the north anatolian fault zone uplifting the gelibolu peninsula and thus severing the connection that existed between the sea of marmara and the paratethys the sea of marmara eventually became an endemic basin by the activity of the north anatolian fault zone

the myth of the brackish sarmatian sea the biota of the 1 5 ma period of the middle miocene sarmatian of the central paratethys lack stenohaline components this was the reason to interpret the sarmatian stage as transitional between the marine badenian and the lacustrine pannonian stages however our new data indicate that brackish water conditions could not have prevailed sarmatian foraminifera molluscs serpulids bryozoans dasycladacean and corallinacean algae as well as diatoms clearly indicate normal marine conditions for the entire sarmatian during the lower sarmatian however a sea level lowstand forced the development of many marginal marine environments during the late sarmatian a highly productive carbonate factory of oolite shoals mass occurrences of thick shelled molluscs and larger foraminifera as well as marine cements clearly point to normal marine to hypersaline conditions this trend is not restricted to the western margin of the pannonian basin system but can be observed in the entire central and even eastern paratethys

paleobiogeography and historical biogeography of the non marine caenogastropod family melanopsidae abstract we investigate the distributions of representatives of the family melanopsidae gastropoda caenogastropoda cerithioidea from the late cretaceous to present day the present contribution discusses and partly revises former schemes of melanopsid dispersal during the cenozoic all of which were based on outdated stratigraphic and tectonic concepts as well as an incompletely considered fossil record conflating a comprehensive and stratigraphically well constrained fossil record modern paleogeographical reconstructions and contemporary climate data our goal is to present a thorough model of melanopsid distribution and its changes over the cenozoic as well as its paleogeographical and climatic constraints the family melanopsidae evolved about 90 ma ago in the late turonian from brackish cerithioidean ancestors cretaceous and paleogene species occur in marginal marine to brackish environments along the shores of the tethys and paratethys seas the extant clades of melanopsis likely derive from the evolution of freshwater melanopsis on the balkan peninsula back in the late early miocene up to the pliocene freshwater species spread toward southwestern and southeastern europe and successively replaced brackish water representatives paralleling a general decline of latter systems during the late cenozoic the southwards expansion of melanopsis and its simultaneous retreat from northern latitudes resulted in the disjunct distribution pattern observed today the genus holandriana first appeared in northern italy in the late early miocene the genera microcolpia and esperiana both first occurred in the late miocene and likely derive from brackish water melanopsis species native to peri paratethyan lakes the present day biogeographic isolation of the three latter genera and melanopsis roots in the climatic deterioration and the disappearance of major lake systems in southeastern europe while thermophilous melanopsis retreated to the warm dry climates of the mediterranean and middle east holandriana microcolpia and esperiana adapted to the seasonal cold temperate climate of southeastern and eastern europe and some species became restricted to thermal springs

interaction between trench retreat and anatolian escape as recorded by neogene basins in the northern aegean sea the evolution of the north aegean sea is studied through the development of three deep basins the north aegean trough the north skyros basin and the ikaria basin bathymetric data a 2d seismic dataset and the well investigated stratigraphic records of the onshore deep basins of northern greece and western turkey were used to make structural and seismic stratigraphic interpretations the study area shows two sharp unconformities that correspond to the eocene oligocene transition and the miocene pliocene shift these discontinuities were used as marker horizons for a more detailed structural and seismic stratigraphic interpretation resulting in the identification of several seismic units a general seismic signature chart was established using onshore basin stratigraphy and well data which was then used to constrain the ages of the different seismic units the main features observed in the basins are interpreted as 1 trans tensional growth patterns in pliocene and quaternary sediments that combine ne sw trending and steeply dipping fault zones that likely correspond to strike slip corridors and e w wnw ese trending normal faults 2 regional erosional truncations of miocene sediments likely related to the messinian salinity crisis msc 3 thick delta turbidite deposits of neogene age only the north aegean trough shows evidence of earlier development and polyphase deformation through inversion structures and additional seismic units extension processes in the aegean region have been driven by the hellenic slab rollback since the middle eocene the widespread development of neogene basins at the whole aegean scale attests to a major tectonic change due to an acceleration of the trench retreat in the middle miocene the present study shows that the neogene basins of the north aegean sea developed in dextral transtension with the northward migration of the associated ne sw trending strike slip faults at regional scale this tectonic pattern indicates that the westward escape of anatolia started to interact with the trench retreat in the middle miocene around 10 myr before the arrival of the north anatolian fault in the north aegean sea

sedimentation and diagenesis of an oligocene manganese deposit in a shallow subbasin of the paratethys thrace basin turkey abstract the northern part of the thrace basin intermittently connected to the paratethys seaway was the site of micritic carbonate sedimentation during the eocene pisolite and coarse shell debris in the earliest oligocene and clastic sediments through into the neogene near the transition from carbonate to clastic facies thin and discontinuous manganese ores at binkilic consist of interlayers of dominantly oxide and lesser carbonate minerals these occur as disseminated pisolitic oolitic concretionary and massive forms chief ore minerals are pyrolusite manganite cryptomelane rhodochrosite and kutnahorite in thin and polished sections mn carbonates in originally calcite monaxon sponge spicules are seen to have been replaced by mn oxides thus documenting the introduction of dissolved mn and major diagenetic alteration of primary calcite to mn carbonate and finally to mn oxide throughout the ore sequence the rees show pronounced positive eu and small negative ce anomalies carbon isotopes in the sequence show a narrow range of values from about 5 to 7 pdb within the range characterizing modern fresh waters the ore body formed during a marine regression and it was positioned adjacent to an embayment in the basin margin facts which support the hypothesis that the ore fluid was groundwater draining from mn bearing rocks of the nearby stranjha massif at a time when the basin was cut off from the paratethys this scenario thus differs significantly from that suggested for penecontemporaneous paratethyan mn deposits redox controlled primary precipitation of oxides and carbonates in segregated environments

assessment of impact of coal mining on ground and surface waters in tozakli coal field kirklareli northeast of thrace turkey in this study the surface and groundwaters of tozakli coal field were investigated in order to determine possible environmental impacts of coal mining on water pollution the water samples were analyzed for chemical trace metal and microbiological quality and compared with international directives epa and who in order to determine the impact of the mining activities as a source of pollution on bodies of water tozakli coal was lignitic rank and sulfur content varied between 9 and 4 the ph values of the waters were between 8 04 and 6 92 for the mine ponds and 8 7 and 6 6 for the groundwater and surface water the ca 2 mg 2 na k cl so 4 2 and no3 values of the waters varied between 394 2 and 52 195 and 1 200 and 22 6 and 1 1 and 0 9 756 and 20 2 4 and 1 1 mg l respectively in the mine ponds all the major cation and anion and trace element concentrations were below admissible limits of both epa and who except for so4 and no3 all the mine ponds and tap waters of the villages were contaminated by enterococcus spp while e coli and total coliforms were only present in the mine pond waters the geoaccumulation index igeo values of the clay samples from the mining area revealed that the soils were moderately contaminated by ni whereas as and ni concentrations had high anthropogenic shares due to coal mining the surface and groundwaters of the study area were not polluted by the coal mining operations

from tethys to eastern paratethys oligocene depositional environments paleoecology and paleobiogeography of the thrace basin nw turkey the oligocene depositional history of the thrace basin documents a unique paleogeographic position at a junction between the western tethys and the eastern paratethys as part of the tethys shallow marine carbonate platforms prevailed during the eocene subsequently a three staged process of isolation started with the oligocene during the early rupelian the thrace basin was still part of the western tethys indicated by typical western tethyan marine assemblages the isolation from the tethys during the early oligocene is reflected by oolite formation and endemic eastern paratethyan faunas of the solenovian stage the third phase reflects an increasing continentalisation of the thrace basin with widespread coastal swamps during the late solenovian the mollusc assemblages are predominated by mangrove dwelling taxa and the mangrove plant avicennia is recorded in the pollen spectra the final continentalisation is indicated by the replacement of the coastal swamps by pure freshwater swamps and fluvial plains during the late oligocene mammal zone mp 26 this paleogeographic affiliation of the thrace basin with the eastern paratethys after 32 ma contrasts all currently used reconstructions which treat the basin as embayment of the eastern mediterranean basin

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

circum mediterranean oligo miocene biogeographic evolution the gastropods point of view based on studies in iran qom basin esfahan sirjan basin zagros mountains in turkey mut and sivas basins in the mesohellenic basin and in northeastern egypt a new palaeobiogeographic concept for the oligocene and miocene in the circum mediterranean area with special emphasis on the distribution patterns of gastropod faunas is presented a very strict biogeographic terminology is proposed to avoid the common fusion of geographic faunistic and geodynamic terms in the palaeontologists jargon our main interest focuses on the affinities and the faunistic interactions between the early mediterranean and the early indo pacific regions during the oligo miocene especially the role of the early indo pacific faunas as the mythic centre of origination of early neogene european mollusc faunas as often vaguely indicated in the literature is critically evaluated this leads to the establishment of a mediterranean iranian province and a western indian eastern african province as palaeobiogeographic subunits of the western tethys region during the oligocene due to major geodynamic and related biogeographic changes in the early miocene the western tethys region no longer existed and was replaced by the proto mediterranean atlantic region for the area of the paratethys the palaeobiogeographic unit danubian province which includes the protocaspian subprovince is proposed furthermore the underrated transatlantic communication of the oligo miocene nearshore mollusc faunas is demonstrated altogether this paper is a contribution to the discussion on the biogeographic concepts classification and nomenclature in palaeontology as initiated by westermann palaeogeogr palaeoclimatol palaeobiogeogr 158 2000 1 13 163 2000 49 68 2002 elsevier science b v all rights reserved

paleoenvironmental evolution of the paratethys in the slovenian basin during the late paleogene several sections from the uppermost eocene and oligocene of northern slovenia have been investigated with respect to sedimentary facies foraminiferal assemblages stable isotopes carbonate microfacies and palynology the main objective was to reconstruct the paleoenvironmental history of the paleogene paratethys in this region of the eastern alpine realm the sediments exhibit a transgressive succession beginning with conglomerates sandstones and mudstones of fluvial and lacustrine origin followed by carbonates and muddy marls indicating marine conditions the foraminiferal faunal changes from brackish to shallow marine to deeper marine assemblages and the distribution of the palynofloras corroborate the sedimentological results microfacies analysis of the limestones shows a wide variation of shallow water generally mud rich facies dominated by coralline algae foraminifera and corals microfaunas adapted to low oxygen conditions indicate temporal sluggish bottom water circulation which can be associated with high fresh water fluxes these results are discussed as reflecting both the global sea level rise during the early oligocene and the regional tectonic and climatic evolution

geochemistry of trace elements in the kesan coal and its effect on the physicochemical features of ground and surface waters in the coal fields edirne thrace region turkey abstract in this study concentration and origin of trace elements of the kesan coals in edirne thrace basin have been investigated in order to determine possible environmental impacts on water pollution the coal ground and surface waters and clay samples were taken from the coal mining area the concentration of trace elements in 14 coal ashes 15 water samples and seven clays was determined by inductively coupled plasma mass spectrometry additionally 11 of these coal samples were studied by proximate and seven coal samples were also studied by x ray diffraction analyses the mineralogical composition of the studied coal samples is made up mainly of quartz clay minerals feldspar group minerals pyrite and amorphous matter the kesan coal ash samples have higher average concentrations of cr 180 ppm ni 192 ppm rb 91 ppm and sr 1701 ppm average values of other trace elements are lower than the world average of brown coal ashes the sulfur content of the kesan coals ranges from 0 4 to 3 90 2 02 on average the ph values of the waters vary between 6 55 and 8 36 in coal fields 7 21 and 7 54 in springs the f cl no 3 so 4 ca mg na and k values of the waters vary between 0 11 and 0 25 mg l 33 49 and 52 90 mg l 0 05 and 59 27 mg l 85 and 2829 mg l 66 and 349 mg l 64 and 222 mg l 41 and 1187 mg l 2 and 13 mg l respectively in coal fields some elements are anomalous in concentrations in some water samples e g cr up to 49 6 ppb mn up to 1185 ppb fe up to 10 352 ppb ni up to 55 8 ppb as up to 9 7 ppb ppb it has been interpreted that the lower trace element concentrations in the water samples may be due to clay intercalated with coal the clays are smectite type and they are enriched in cr co ni as sr and th e g up to 394 ppm cr up to 305 ppm ni and up to 35 5 ppm as

unusual micro and nano inclusions in diamonds from the juina area brazil abstract a series of uncommon micro and nano inclusions has been identified in diamonds from the rio soriso placer deposit in mato grosso state brazil the micro inclusions are variable in size from 1 to 300 m usually they are polymineralic being formed predominantly by intergrowths of carbonates silicates and other minerals carbonates are represented mostly by dolomite and occasionally by calcite silicates found are coesite wollastonite ii cuspidine and monticellite sulphides and ilmenite form micro inclusions as well nano inclusions are different from micro inclusions not only in size not exceeding 200 nm they are usually included in micro inclusions among nano inclusions halides nacl kcl cacl2 and pbcl2 anhydrite spinel phlogopite pbo2 tio2 with an pbo2 structure native fe and other phases are identified all these minerals are of the eclogitic association they are either associated with coesite or are included in a diamond with a light organic carbon isotopic composition with 13c from 14 to 25 pdb this confirms our earlier conclusion that diamonds from the juina area may have formed as a result of subduction of the crustal material to depths of at least the lower transition zone or even the lower mantle the pressure estimates for the investigated diamonds vary in a range from 3 to 10 gpa an interesting assemblage of calcite cuspidine wollastonite monticellite fluid identified in one of the studied diamonds is considered as a product of a reaction of wollastonite fluid forming cuspidine monticellite the presence of numerous pores cavities and bubbles in mineral inclusions and identification of an association of volatile containing mineral inclusions such as halides nacl kcl cacl2 and pbcl2 fluorine containing silicate cuspidine and phlogopite emphasize the important role of volatiles particularly chlorine and fluorine in the formation of the diamonds

palaeoenvironmental reconstructions by stable isotopes of middle miocene gastropods of the central paratethys abstract the stable isotopes of carbon and oxygen were used to provide information of mixing of marine and freshwater and subsequently used to determine palaeosalinities in the middle to late miocene st margarethen zollhaus section upper sarmatian mactra zone pannonian a succession of three gastropod assemblages indicates changing environmental conditions from a limnic fluviatile to littoral mudflat and a sublittoral marine environment several shells of the main representatives of the three assemblages potamides hartbergensis hilber granulolabium bicinctum brocchi potamides disjunctus sowerby and additionally shells of lymnaea sp a typical freshwater gastropod and pomatias conicus a terrestrial gastropod were taken for stable isotope analyses oxygen and carbon isotope data of the freshwater endmember are distinctively lower 18 o 4 5 13 c 9 than of the marine endmembers 18 o 2 2 13 c 2 3 in contrast to the expected intermediate isotopic composition between the freshwater and marine environment the shells of supposed brackish environments have higher 18 o values than the shells of the marine environment these higher 18 o values are explained by evaporation which affected the protected areas of riverine to lacustrine environments and small pools on mudflats formerly considered to be the habitats of the brackish assemblages thus the oxygen and carbon isotope data extend the already existing palaeoenvironmental information

eocene oligocene stratigraphy and structural history of the karaburun area southwestern black sea coast turkey transition from extension to compression the stratigraphic succession exposed in the karaburun area southern black sea coast nw turkey records multiple changes in depositional and tectonic settings during cenozoic times it starts with the middle upper eocene sogucak formation of reef limestone that across a normal fault omitting the lower part of the lower oligocene ceylan formation deep marine shale unit abuts the upper part of the ceylan formation that is made up of two facies 1 shallow marine sandstone and 2 shallow marine limestone units containing horizons of submarine slumps both facies are unconformably overlain by the fluvial upper miocene cukurcesme formation the tectonic record includes 1 latest eocene early oligocene ne sw extension 2 early oligocene ne sw shortening and 3 late miocene nw ne extension the earliest normal faults cutting the sogucak and the lower part of the ceylan formations are associated with clastic dykes injected into the deep marine shale these structures suggest a disruption of the eocene carbonate platform and are also known in the neighbouring thrace basin the following ne sw shortening created the ne vergent karaburun thrust that is synchronous with the shallowing and inversion of the ceylan basin rotation of the stress field is recorded by changes in clastic dyke orientation and their deformation compression caused multiple westerly directed submarines slides from uplifts in easterly located regions this event is not recorded in the thrace basin finally the miocene tectonic activity formed nw and ne striking normal faults the outlined tectonic history includes early oligocene extensional and compressional episodes recorded in the southern margin of the black sea that had hitherto not been known

the region of the strandja sill north turkey and the messinian events the two sides of the strandja sill show a highly discontinuous stratigraphic succession since the late oligocene this area together with the sea of marmara basin is usually proposed as the gateway for the paratethyan freshwaters and organisms that constituted the lago mare facies in the mediterranean sea during the messinian salinity crisis msc our investigations involving new field observations and datings together with previous studies suggest that the sill has possibly experienced such a connection at around 8 ma i e significantly before the crisis the proposal of a sea level drop of the black sea before 7 ma is not supported by our data on dinoflagellate cysts consistency of calcareous nannofossil succession at dsdp site 380 is reinforced allowing to reassert that subaerial erosion impacted both the southwestern black sea and the central marmara dardanelles area during the peak of the msc at that time this region was crossed by two oppositely directed fluvial networks further supporting the absence of a marine gateway through the strandja sill it is concluded that none of the lago mare events recorded in the mediterranean during the msc were the consequence of the passage of paratethyan waters and organisms through this area in the black sea the well dated messinian fluvial erosion can be followed offshore the overlying prograding deltaic deposits attest to a fast marine reflooding after the crisis this constitutes a comprehensive erosion sedimentation model in an area intensively explored for hydrocarbons

sedimentology and stratigraphy of cenozoic deposits in the kagizman tuzluca basin northeastern turkey the kagizman tuzluca basin is located in the northeastern anatolia to the east of the intersection point near karliova of the major north and east anatolian fault systems this intermontane basin displays a thick sequence over 2000 m of mostly terrestrial deposits represented by repetitive alternations of the lake and fluvial environments ranging from late eocene oligocene to middle late miocene a marine incursion only mappable in the southeastern margin of the basin deposited limestones and sandy limestones rich in marine mollusks and nummulites in particular n fichteli that constrain an early oligocene age for this marine unit kagan fm the terrestrial basin fill deposits show different thicknesses throughout the basin due to irregular bottom topography and tectonic configuration of the basin margins the thickest deposits were accumulated along the different margins of the basin which received high quantities of siliciclastics from meandering river alluvial and coastal fans fan delta gilbert type delta and wave worked fluvial delta climate changes have also driven the development of lake environments during distinct depositional periods siliciclastic dominated overfilled lakes halikislak and kizilkaya formations and chemical dominated underfilled lakes turabi and tuzluca formations were formed they have been also classified as newark type and fundy type lakes respectively fluvial systems evolved from high energy meandering rivers deposited under humid climate gungoren formation to low energy meandering rivers resulted from arid and semiarid climates cincavat formation the transitional intervals from ephemeral river dry mudflat cincavat formation to saline pan lake tuzluca formation indicate wadi sand flat playa fluvial systems the chronostratigraphic constrains of the entire sequence remain poor and so far solely based on vertebrate fossil assemblages the evaporitic tuzluca formation would be middle miocene in age due to its stratigraphic position over the cincavat formation