a gradual drowning of the southwestern black sea shelf evidence for a progressive rather than abrupt holocene reconnection with the eastern mediterranean sea through the marmara sea gateway core m02 45 recovered 9 5 m of a 12 m thick transgressive succession on the sw black sea shelf the underlying transgressive unconformity a deepens toward the shelf edge so that the coresite was never isolated from the open black sea fourteen radiocarbon dates indicate sedimentation from 9 3 ka to the present with only one hiatus at 270 cm depth spanning 4 5 2 5 ka three units are present in the core unit a 0 270 cm burrowed mud with laminated silt beds and mollusc shells of mediterranean affinity accumulation rate 125 cm ky unit b 270 525 cm silty mud with shelly interbeds containing truncatella subcylindrica mytilus galloprovincialis parvicardium exiguum rissoa spp and modiolula phaseolina rate 85 cm ky unit c 525 950 cm burrowed silty mud with graded beds of silt and fine sand and shells of t subcylindrica p exiguum and dreissena polymorpha rate 360 cm ky unit c developed below storm wave base at a time when proponents of a catastrophic flood in the black sea claim that the shelf was subaerially exposed clearly it was not ostracoda of caspian affinity indicate 5 salinity until 7 5 ka dinocysts and foraminifera confirm a low but rising salinity after 8 6 ka an increase of d 34 s from 5 30 through 8 4 7 6 ka is attributed to a first pulse of sulfate rich aegean water into an already high black sea after which this sulfate was quantitatively precipitated as sulfide d 34 s then dropped at 8k a to 20 as dysoxia and water column stratification were established because of the initiation of two way flow through the bosphorus earlier water exchange with the mediterranean was likely impeded by strong black sea outflow which prevented easy access of the aegean water mass r 2006 published by elsevier ltd

was the black sea catastrophically flooded in the early holocene abstract a catastrophic flooding of the black sea basin was proposed to have occurred during its reconnection to the ocean in the early holocene possible cultural consequences of the flood include the migration of neolithic farmers from around the black sea towards central europe as well as the creation of flood myths stratigraphic and paleo geomorphologic information from danube delta aided by radiocarbon ages on articulated mollusks constrain the level in the black sea before the marine reconnection to ca 30 m below the present sea level rather than 80 m or lower if the flood occurred at all the sea level increase and the flooded area during the reconnection were significantly smaller than previously proposed

did postglacial catastrophic flooding trigger massive changes in the black sea gas hydrate reservoir after the last glacial maximum the semi land locked black sea basin was flooded by warm water from the mediterranean sea this major sea level rise and change of physical water properties had a large impact on the gas hydrate reservoir in the sediments below modelling of the regional response of the gas hydrate stability zone ghsz to the black sea flooding 7100 years ago shows that a strong effect of near bottom temperature increase pushes the gas hydrate reservoir to a large shrinking of 15 62 that may release up to 1 1 4 6 gt of methane this catastrophic scenario is however delayed because of the transient nature of the heat wave propagation the large scale reduction of the ghsz is only to take place within the next thousand years at present widespread hydrate dissociation is only expected to occur where there is a minimum water depth for hydrate stability

glacial hydrologic conditions in the black sea reconstructed using geochemical pore water profiles abstract chloride and 18 o compositions of interstitial water extracted from a long sediment core retrieved from the nw coast of the black sea allowed us to constrain the main hydrologic changes of the back sea during the late pleistocene and holocene prior to its reconnection with the mediterranean sea through the marmara sea at approximately 9000 calendar yr before present 9 ka cal bp the black sea has evolved as a fresh to brackish water lake at the time of reconnection hydrologic changes were drastic bottom water salinities changed from a few psu practical salinity unit to 22 psu since solutes in the interstitial water column within sediments are advected and diffused the measured concentrations do not reflect those of past bottom waters in order to reconstruct these former concentrations we used an advection diffusion model different scenarios of bottom water chloride and 18 o variations were accounted for in this model in order to simulate present day vertical profiles for concentrations of interstitial water in order to compare them to measured ones the comparison suggests that the glacial black sea was a homogeneous freshwater lake with a 18 o of 10 and a salinity of 1 psu modern hydrologic conditions would only have been reached at 2 ka cal bp concomitant with the onset of coccolith rich thin layers that characterize modern basin sediments such delayed salinization over 7000 yr in the basin may have been due to higher precipitation during the early holocene we also simulated the impact of a catastrophic reconnection and a smoother reconnection both salinity scenarios lead to undistinguishable modelled present day profiles indicating that the precise impact of the last reconnection was lost due to the advection diffusion processes

climatic controls on holocene lake level changes in europe sensitivity experiments with a simple water balance model were used to constrain the possible climatic causes of distinct holocene patterns of lake level variation in different regions of europe lakes in s sweden were low at 9 ka high around 6 5 ka low again around 4 ka and are high now lakes in estonia show similar but weaker trends lakes in s france were highest around 9 ka lowest around 4 ka intermediate now lakes in greece were also high around 9 ka but continued rising until 7 5 ka then fell gradually from 5 ka with a brief high phase around 3 ka and are low now the model was forced with insolation anomalies deduced from orbital variations temperature anomalies inferred from the pollen record and cloudiness anomalies derived from changes in the position of the subtropical anticyclone inferred from reconstructed changes in the equator to pole temperature gradient in order to evaluate the effects of resultant evaporation changes on catchment water balance the resulting simulated changes in runoff precipitation minus actual evapotranspiration were slight and frequently opposite to the observed trends larger changes in precipitation are plausible and are required to explain the data the required precipitation increase in n europe from 9 ka low to 6 ka high is suggested by gcm experiments to have been a consequence of interacting insolation and residual ice sheet effects on the atmospheric circulation over the north atlantic the explanation of other observed changes including the drying trend during the holocene in s europe has not been provided by gcm experiments to date explanations may lie in changes in mesoscale circulation sea surface temperature patterns and the coupling between these phenomena that may not follow orbital changes in any simple way

the holocene black sea reconnection to the mediterranean sea new insights from the northeastern caucasian shelf abstract recent findings about the evolution of palaeogeographic conditions of the black sea during the holocene have significantly improved our understanding of the profound environmental changes that took place around 9 ka ago when the neoeuxinian lake reconnected to the global ocean in contrast to the western and southeastern regions where numerous studies have been recently performed the northeast region remains relatively under investigated we carried out the first multi proxy continuous study of a sediment core ak 2575 from the northeastern black sea shelf that includes benthic calcareous fossils ostracods molluscs and foraminifers dinoflagellate cysts dinocysts and sedimentology thus providing reconstructions of surface and bottom water conditions the age model of the core is based on 10 ams 14 c dates calibrated ages are used throughout the manuscript the first appearance of mediterranean elements is documented at 9 6 cal ka bp our data provide evidence of sustained cohabitation of benthic species of caspian and mediterranean origins represented by different ontogenetic stages from at least 7 8 or even 8 8 to 6 7 cal ka bp with the gradual disappearance of brackish species suggesting a gradual increase in salinity and most likely a change in the salt composition dinocyst assemblages show species succession that is coherent across the black sea basin with brackish taxa dominating until 8 5 cal ka bp and being slowly replaced by euryhaline species the occurrences of authigenic gypsum crystals especially abundant at 7 4 and 6 5 cal ka bp suggest the temporal appearance of hydrogen sulphide at the shelf edge which during certain periods appears to reduce the abundance of benthic fauna

late quaternary history of the marmara sea and black sea from high resolution seismic and gravity core studies abstract lithologic and multi proxy paleoenvironmental data from 21 dated cores have been used to define three allostratigraphic units allounits within the late quaternary successions of the marmara sea and black sea allounits are bounded by unconformities and their correlative conformities in both regions allounit a extends from the seafloor downward to a 12 11 ka sequence boundary which is a major shelf crossing unconformity in water depths less than 100 110 m in deep basins of the marmara sea the lower part of allounit a designated subunit a2 is a laminated sapropel m1 on the shelf subunit a2 consists of backstepping delta lobes and early transgressive barrier islands and sand sheets allounit b has only been recovered in marmara sea cores collected at water depths greater than 90 m and represents basinal or prodeltaic deposition during the 23 12 ka late pleistocene lowstand during the last glacial maximum the shelves surrounding the marmara sea were subaerially exposed and deltas of allounit b accumulated along the present day shelf edge following the post glacial rise of global sea level to 75 m at 12 ka the marmara sea quickly became inundated and thereafter rose in synchroneity with the mediterranean by 10 ka the black sea rose to start spilling into the marmara sea leading to establishment of a brackish water lid that has persisted to the modern day the strongest black sea outflow began at 10 ka and persisted to 6 ka promoting the accumulation of sapropel m1 in the deep marmara sea and progradation of an overflow delta just south of the exit from the bosphorus strait allounit c is a laminated sapropel m2 in basinal cores dated at 30 23 ka like m1 it is believed that m2 accumulated during a period of increased brackish water input into the marmara sea mainly from the black sea in the black sea wave erosion kept the shelf stripped of unconsolidated sediments during the falling sea level associated with the last glaciation and subsequent early stages of the post glacial holocene transgression this erosion created a major unconformity shelf edge deltas of allounit b received their sediment during the last lowstand from small rivers that likely coalesced into a single system toward the shelf edge at modern water depths of 100 to 110 m these deltas were active until 11 10 5 ka subsequently sea level in the black sea rose to 40 m by 10 ka and a set of backstepping barrier islands developed on the shelf as part of the associated transgressive systems tract once water level reached 40 m continued sea level rise stalled until 9 ka as the black sea began to spill across the bosphorus strait into the marmara sea

geological and morphological setting of 2778 methane seeps in the dnepr paleo delta northwestern black sea abstract the dnepr paleo delta area in the nw black sea is characterized by an abundant presence of methane seeps during the expeditions of may june 2003 and 2004 within the eu funded crimea project detailed multibeam seismic and hydro acoustic water column investigations were carried out to study the relation between the spatial distribution of methane seeps sea floor morphology and sub surface structures 2778 new methane seeps were detected on echosounding records in an area of 1540 km 2 all seeps are located in the transition zone between the continental shelf and slope in water depths of 66 to 825 m the integration of the different geophysical datasets clearly indicates that methane seeps are not randomly distributed in this area but are concentrated in specific locations the depth limit for the majority of the detected seeps is 725 m water depth which corresponds more or less with the stability limit for pure methane hydrate at the ambient bottom temperature 8 9 c in this part of the black sea this suggests that where gas hydrates are stable they play the role of buffer for the upward migration of methane gas and thus prevent seepage of methane bubbles into the water column higher up on the margin gas seeps are widespread but accurate mapping illustrates that seeps occur preferentially in association with particular morphological and sub surface features on the shelf the highest concentration of seeps is found in elongated depressions pockmarks above the margins of filled channels on the continental slope where no pockmarks have been observed seepage occurs along crests of sedimentary ridges there seepage is focussed by a parallel stratified sediment cover that thins out towards the ridge crests on the slope seepage also appears in the vicinity of canyons bottom flanks and margins or near the scarps of submarine landslides where mass wasting breaches the fine grained sediment cover that acts as a stratigraphic seal the seismic data show the presence of a distinct gas front which has been used to map the depth of the free gas within the sea floor sediments the depth of this gas front is variable and locally domes up to the sea floor where the gas front approaches the seafloor gas bubbles were detected in the water column a regional map of the sub surface depth of the gas front emphasises this gas front versus seep relationship the integration of all data sets indicates that the spatial distribution of methane seeps in the dnepr paleo delta is mainly controlled by the gas hydrate stability zone as well as by stratigraphic and sedimentary factors

architecture of late orogenic quaternary basins in northeastern mediterranean sea abstract in the northeastern mediterranean sea pliocene to quaternary depocentres have formed in extensional basins bounded by splays of the east anatolian transform fault this tectonic regime is superimposed on a miocene and older back arc environment that experienced late miocene compression along the misis kyrenia thrust which now lies in the middle of the extensional zone the thrust zone is now represented by a narrow horst that appears to be bounded by strike slip faults pliocene quaternary extension took place on listric fault fans that are orthogonal to the bounding transform splays and sole at a messinian evaporite horizon and on some deeper soling listric faults parallel to and near the bounding faults the rapid extension has resulted in progressive landward migration of paleoshorelines and low depositional gradients glacio eustatic fluctuations in shoreline positions strongly influenced sediment distribution most sediment dispersion was from deltaic plumes with turbidites of minor significance depocentres landward of the maximum seaward extent of paleoshorelines were formed almost entirely by tectonic subsidence minor deep water depocentres controlled by halokinesis accumulated mud turbidites during extreme low stands of sea level

abrupt changes of temperature and water chemistry in the late pleistocene and early holocene black sea new mg ca sr ca and published stable oxygen isotope and 87sr 86sr data obtained on ostracods from gravity cores located on the northwestern black sea slope were used to infer changes in the black sea hydrology and water chemistry for the period between 30 to 8 ka b p calibrated radiocarbon years the period prior to 16 5 ka b p was characterized by stable conditions in all records until a distinct drop in 18o values combined with a sharp increase in 87sr 86sr occurred between 16 5 and 14 8 ka b p this event is attributed to an increased runoff from the northern drainage area of the black sea between heinrich event 1 and the onset of the bolling warm period while the mg ca and sr ca records remained rather unaffected by this inflow they show an abrupt rise with the onset of the bolling allerod warm period this rise was caused by calcite precipitation in the surface water which led to a sudden increase of the sr ca and mg ca ratios of the black sea water the stable oxygen isotopes also start to increase around 15 ka b p although in a more gradual manner due to isotopically enriched meteoric precipitation while sr ca remains constant during the following interval of the younger dryas cold period a decrease in the mg ca ratio implies that the intermediate water masses of the black sea temporarily cooled by 1 2 c during the younger dryas the 87sr 86sr values drop after the cessation of the water inflow at 15 ka b p to a lower level until the younger dryas where they reach values similar to those observed during the last glacial maximum this might point to a potential outflow to the mediterranean sea via the sea of marmara during this period the inflow of mediterranean water started around 9 3 ka b p which is clearly detectable in the abruptly increasing mg ca sr ca and 87sr 86sr values the accompanying increase in the 18o record is less pronounced and would fit to an inflow lasting 100 a

review of the late quaternary stratigraphy of the northern gulf of cadiz continental margin new insights into controlling factors and global implications abstract over the past decades the northern gulf of cadiz has been the focus of a wide range of late quaternary seismic and sequence stratigraphic studies either addressing the slope contourite depositional system cds or the development of the continental shelf yet high resolution seismic data bridging between these domains and age information have remained sparse this study based on new high resolution reflection seismic profiles calibrated to iodp expedition 339 sites u1386 u1387 now presents an updated stratigraphic framework that integrates for the first time the late quaternary records of the northern gulf of cadiz middle slope to shelf off the guadiana river seismic stratigraphic analysis of the stacking depocenter distribution stratal architecture and facies of the seismic sub units reveals the influence of 100 kyr sea level variations paced by milankovitch eccentricity cycles tectonics manifesting as two pulses of uplift and margin progradation sediment supply and bottom current activity this work furthermore contributes to the application and understanding of high resolution late quaternary sequence stratigraphy firstly the proposed sequence stratigraphic interpretation shows that adaptations to the basic models are required to integrate the shelf and slope record and to account for the presence of a significant alongslope bottom current controlled component secondly the results confirm that the sequences are dominantly composed of regressive deposits whereas the preservation of transgressive to highstand deposits is more irregular significantly the common assumption that successive major glacial lowstands are consistently recorded as well marked shelf wide erosional unconformities is demonstrated to be occasionally invalid as tectonics can obliterate this one to one relationship

further evidence of abrupt holocene drowning of the black sea shelf a 1999 survey of the black sea continental shelf off the north central turkish seaport of sinop using a side scan sonar small remotely operated vehicles and a series of dredge lowerings located inspected and sampled an exposed high energy paleoshoreline at a depth of 155 m radiocarbon dating of mollusk shells collected from this ancient beach revealed that the marine flooding of the black sea took place between 7460 and 6820 yr b p all ages are reported in radiocarbon years not calendar years without correction for reservoir age or dendro calibration changing it from a lacustrine to marine environment this relic surface remained in contact with the bottom waters of the black sea for a long period of time before being draped by a thin layer of sapropel mud wood samples recovered from this same location were very well preserved and yielded dates as old as 3580 yr b p q 2000 elsevier science b v all rights reserved

the ponto caspian basin as a final trap for southeastern scandinavian ice sheet meltwater this paper provides new data on the evolution of the caspian sea and black sea from the last glacial maximum until ca 12 cal kyr bp we present new analyses clay mineralogy grain size nd isotopes and pollen applied to sediments from the river terraces in the lower volga from the middle caspian sea and from the western part of the black sea the results show that during the last deglaciation the ponto caspian basin collected meltwater and fine grained sediment from the southern margin of the scandinavian ice sheet sis via the dniepr and volga rivers it induced the deposition of characteristic red brownish chocolate coloured illite rich sediments red layers in the black sea and chocolate clays in the caspian sea that originated from the baltic shield area according to nd data this general evolution common to both seas was nevertheless differentiated over time due to the specificities of their catchment areas and due to the movement of the southern margin of the sis our results indicate that in the eastern part of the east european plain the meltwater from the sis margin supplied the caspian sea during the deglaciation until 13 8 cal kyr bp and possibly from the lgm that led to the early khvalynian transgressive stage s and chocolate clays deposition in the now emerged northern flat part of the caspian sea river terraces in the modern lower volga and in its middle basin in the western part of the east european plain our results confirm the release of meltwater from the sis margin into the black sea that occurred between 17 2 and 15 7 cal kyr bp as previously proposed indeed recent findings concerning the evolution of the southern margin of the sis and the black sea show that during the last deglaciation occurred a westward release of meltwater into the north atlantic between ca 20 and 16 7 cal kyr bp and a southward one into the black sea between 17 2 and 15 7 cal kyr bp after the red layers chocolate clays deposition in both seas and until 12 cal kyr bp smectite became the dominant clay mineral the east european plain is clearly identified as the source for smectite in the caspian sea sediments in the black sea smectite originated either from the east european plain or from the danube river catchment previous studies consider smectite as being only of anatolian origin however our results highlight both the european source for smectite and the impact of this source on the depositional environment of the black sea during considered period

oxygen isotopes and sea level from the time that detailed oxygen isotope records derived from foraminifera living in the constant temperature environment of the abyssal ocean became available there has been a discrepancy between the ice volume record that these records imply and that derived from the altitude of dated coral terraces around the world here we re examine the data and conclude that the temperature of the abyssal ocean has been an actively varying component of the climate system

late pleistocene holocene sea level dynamics in the caspian and black seas data synthesis and paradoxical interpretations abstract different multidisciplinary data concerning the paleodynamics of sea level variations in the caspian and black seas are controversial in some aspects there are at least three paradoxes that are discussed in the paper the paradox no 1 relates to the early and late khvalynian transgressions that occurred in the cs during the second part of mis 3 35 25 ka bp and the late glacial epoch 17 12 ka bp respectively it is unclear what the main source or sources of water were that caused them paradox no 2 emerges from the comparison of climate events and transgressive regressive cycles in the caspian sea and the black sea it implies that large sea level anomalies occurred in accordance with global climate changes because they are influenced by climate variations however other not so long lived sea level fluctuations are poorly correlated with climate events the question is why climatically induced sea level changes did not follow climatic variations paradox no 3 concerns the contradiction between the massive water discharge from the black sea into the sea of marmara via the bosphorus strait and the black sea level fluctuations in the latest pleistocene holocene that could not exist simultaneously it is shown that paradox no 2 has been solved at least on conceptual level solutions to paradoxes no 1 and no 3 are still lacking further geological and geochronological evidence as well as climate simulation are required formulation of solutions for these paradoxes should make a major contribution not only to the problems of the caspian and black seas paleogeography but also provide help in explaining the reasons for inadequate simulation of regional climate changes this is important in the context of the development of models for future climate prediction

architecture of stacked quaternary deltas correlated with global oxygen isotopic curve a distinctive pattern of quaternary stacked prograded deltas and intervening transgressions on a rapidly subsiding continental margin in the eastern mediterranean has been dated from offshore wells simple modeling using the quaternary oxygen isotope record as a proxy sea level curve has demonstrated that this pattern is a consequence of sea level change the progradational pattern is dependent principally on the amount of time that is available between successive highstands to provide accommodation space by subsidence on rapidly subsiding continental margins the standard pattern of stacked deltas can be used as a chronological tool in undated quaternary seismic sequences

constraining holocene sea surface conditions in the south western black sea using dinoflagellate cysts this paper presents two dinoflagellate cyst records from the south western shelf of the black sea a new site mar05 13 from the sakarya shelf is described and placed into context with site mar02 45 250 km distant on the thracian shelf the records provide a centennial resolution of surface water conditions in the holocene analysis of the data suggests that the surface salinity of the south western shelf increased in a gradual and progressive manner in the period 11 000 9000 cal a bp the assemblages suggest surface water salinities between 7 13 psu the initial arrival of euryhaline species 8100 cal a bp is linked to the reconnection of the black sea and marmara sea the suggested surface water changes related to the reconnection took approximately 1000 years following this initial change in assemblages a further increase in the number of euryhaline species is noted between 5000 and 4000 cal a bp this is linked to the establishment of more saline surface water conditions close to present day values the record for mar05 13 highlights the complexity of the changes in cyst assemblages during the mid holocene copyright 2012 john wiley sons ltd

flexure due to the messinian pontian sea level drop in the black sea paleowater depth observations suggest that a large sea level drop occurred in the black sea coeval with the messinian salinity crisis in the mediterranean sea this sea level drop would have induced vertical motions of the solid earth which influenced strait dynamics with major implications for the hydrological regime of the region using three dimensional flexure models we find that a sea level drop between 1730 and 2230 m is required to reproduce the observed paleowater depths the models predict that uplift reduced the seaway connectivity between the black sea and the mediterranean sea aegean region and between the black sea and the caspian sea stavropol highlands the miocene paratethys sea consequently became fragmented and the remaining subseas likely became more sensitive to climate change this agrees with the discovery of erosional surfaces in the caspian sea and in the pannonian basin to explain the synchronicity of the sea level lowering in the black sea and the mediterranean we speculate that a regional shift toward a drier climate occurred in response to the messinian salinity crisis in the mediterranean which led to a fall in sea level within the black sea

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

quaternary sedimentary history of adana cilicia and iskenderun basins northeast mediterranean sea detailed single channel airgun and 3 5 khz profiles from the northeastern mediterranean sea show that the continental shelf is formed by superimposed deltaic successions depositional sequences separated by major erosional unconformities each depositional sequence is composed of a sigmoid prograding package overlain by an oblique prograding package representing respectively delta progradation during high and low sea levels of interglacial and subsequent glacial stages during the glacio eustatic lowstands of sea level deltas prograded seaward the present day shelf break denotes the topset to forest transition at maximum progradation during the last glacial period during post glacial transgressions the deltas initially lost their dynamic equilibrium with the environment and rapidly retreated landward leading to the deposition of a thin veneer of sediments originating from reworking of formerly coastal sediments at the highstand position the deltas were re established in the ancestral adana bay and foreset progradation started chronology suggests that the cilicia and iskenderum basins are subsiding at rates of 0 38 m 1000 yr 1 and 0 33 m 1000 yr 1 respectively seismic reflection profiling shows that delta architecture in the adana cilicia and iskenderun basins is mainly controlled by glacio eustatic sea level fluctuations and continuous basin subsidence

a post younger dryas black sea regression identified from sequence stratigraphy correlated to core analysis and dating the north western black sea shelf is the widest continental shelf of the black sea where the danube delta prodelta system includes important records on the black sea water level fluctuations this study integrates newly acquired high resolution single channel seismic reflection profiles and calypso piston cores recovered along a transect extending from the danube delta deep into its deep sea fan the correlated results provide information on the late quaternary architecture of the danube black sea shelf and on the role of global glacio eustatic fluctuations on the building of the danube delta prodelta the sedimentary sequences in the black sea are strongly affected by water level changes for the whole duration of late glacial holocene period the level of the black sea was controlled by the regional climate modifications rather than the global eustatic changes the seismic sequences recognized on a very high resolution seismic profile were dated by two calypso piston cores based on the obtained data during the last glacial maximum the black sea was a land locked lake with the level below 120 m in the course of the deglaciation the lake level rose up to 40 m which is confirmed by occurrence of the prodelta lobes formed after the rise in water level originated from the melt water following the younger dryas 11 000 8500 c 14 bp there occurred a new level lowering to the level of 100 m identified by the forced regression deposits recorded on the romanian shelf this last lowstand previously recognized by a pronounced shoreline with a characteristic beach profile and a belt of coastal dunes is also indicated by the prodelta at 100 m depth all these coastal features as well as the incised anastomosed channel system remained preserved on the shelf resulting from a rapid ultimate transgression starting immediately after 8500 c 14 bp c 2010 elsevier ltd and inqua all rights reserved

aspects of carbon isotope biogeochemistry of late quaternary sediments from the marmara sea and black sea abstract the marmara sea is situated between the world s largest permanently anoxic basin the black sea and an enclosed marginal sea the aegean sea which experienced quasi periodic sapropel deposition since miocene time it is connected to the black sea and the aegean sea through the straits of bosphorus and dardanelles respectively sapropel m1 which contains from 1 to 2 total organic carbon was deposited in the marmara sea between 6 and 10 5 ka we inferred the carbon isotopic composition of dissolved inorganic carbon dic in the water column of the marmara sea before during and after the deposition of sapropel m1 from the carbon isotopic composition of a planktonic foraminifera turborotalita quinqueloba and individual hexadecanoic and octadecanoic fatty acids the period of sapropel deposition is marked by a depletion of 13 c in the water column dic contrary to what may be expected if sapropel deposition represents a period of enhanced primary productivity instead we propose that both the relative 13 c depletion of dic during sapropel deposition and the absolute values we estimated 13 c 13 to 14 are consistent with enhancement of the relative contribution of 13 c depleted respired carbon to the water column dic pool such enhancement possibly resulted from density stratification that existed during sapropel m1 deposition the existence of density stratification is also argued from palynological and other lines of evidence other papers in this issue and is believed to have resulted from the encroachment of black sea water into the sea of marmara before 10 000 yr ago thus sapropel m1 appears to have formed during periods of enhanced runoff and preservation and not enhanced primary productivity

reply to comment on the timing and evolution of the post glacial transgression across the sea of marmara shelf south of istanbul by hiscott et al marine geology 248 228 236 in their comment hiscott and co authors adhere rigidly to ages and sources for sedimentary units in the subsurface of the marmara shelf that they have previously reported in their publications from 2002 through 2007 this adherence is in spite of a superior age depth model from our 13 m long sediment core that penetrated deeply into the deposits under consideration and in disregard to the results of subsequent more detailed and full coverage mapping of the region under scrutiny the age revisions are dismissed by the authors of the comment as representing sediments severely disturbed during coring we rebut this criticism the bosporus source attributed by them to the sedimentary units sampled and dated by us appears to be driven by their conception that the black sea had a persistent outflow prior to its two way connection with marmara irrespective of whether the outflow was persistent our reply shows that the drawing of the isopachs of the sedimentary units by hiscott and co authors was accomplished in a fashion to promote the bosporus source hypothesis regardless of the geographic limits of their survey the ages assigned to the units are equally indeterminate because the cores used by them have missing core tops of unknown lengths that are not discussed in their publications furthermore the sub bottom reflectors at the sites where the reflectors were calibrated to their only core without a missing top are actually hidden by the finite width of the bottom reflecting wavelet

an abrupt drowning of the black sea shelf abstract during latest quaternary glaciation the black sea became a giant freshwater lake the surface of this lake drew down to levels more than 100 m below its outlet when the mediterranean rose to the bosporus sill at 7 150 yr bp 1 saltwater poured through this spillway to refill the lake and submerge catastrophically more than 100 000 km2 of its exposed continental shelf the permanent drowning of a vast terrestrial landscape may possibly have accelerated the dispersal of early neolithic foragers and farmers into the interior of europe at that time

comment on the timing and evolution of the post glacial transgression across the sea of marmara shelf south of istanbul by eris et al marine geology 243 57 76 abstract in their recent paper eris and co authors attempt to refute much of our work on deltaic sediments at the southern exit of the bosphorus strait turkey first their age model is completely inconsistent with the well constrained chronology of our cores mar02 110 and mar02 111 their calypso core md 2750 must have seriously oversampled the holocene section giving an erroneous impression of true thicknesses and ties to seismic data and therefore leading to an incorrect assessment of the timing of deltaic sedimentation second they have ignored evaporative drawdown in the marmara sea from 14 7 11 3 ka lowering of the sea surface by evaporation is a better explanation for a lowstand shoreline at 83 m elevation than their proposal that the dardanelles sill was this deep at the time of reconnection with the global ocean third we contest their conclusion that the uppermost delta in this area was sourced from the kurbagalidere river the sediment flux of this river is too little it cannot account for the strong upward climb of the topset to foreset transition into a rapidly rising ocean and eris et al make no attempt to explain the absence of a precursor shelf edge delta that would be mandatory if this river had the water and sediment discharge that they suggest

stratal architecture of western mediterranean margins as the result of the stacking of quaternary lowstand deposits below glacio eustatic fluctuation base level abstract through a comparison of high resolution seismic stratigraphy of seven western mediterranean margins similarities and differences in stratigraphic architecture were highlighted and a hierarchy of controlling factors was established the areas are northwestern alboran ebro and northern catalonia in the spanish margin rho ne in the french margin and tuscany latium and calabria in the italian tyrrhenian margin despite their different tectonic physiographic and depositional setting the seismic facies and growth pattern of the middle late pleistocene deposits are comparable the margins are in fact the result of the stacking of lowstand systems tracts of 4th order depositional sequences bounded by polygenetic unconforniities on the shelf and condensed sections on the upper slope this lowstand nature results from the high frequency 100 ka high amplitude 100 m asymmetry falling 65 of the time and stationariness between 10 and 120 m with respect to the present of the glacio eustatic sea level curve if eustasy directly controls the types of deposits making up the margins tectonism conditions their growth pattern as it is the only factor accounting for similarities and differences in the external geometry stratal pattern and distribution of the middle late pleistocene depositional sequences an evolutionary model for the quaternary growth of young passive continental margins is proposed in this model tectonics determines the degree of preservation of lowstand deposits because it conditions the accommodation space left below the erosional profile produced by each glacio eustatic cycle thus some of the sequence stratigraphy principles widely used to set up the model have been modified and adjusted to take into consideration the peculiar nature of quaternary glacio eustasy

holocene paleoecology and paleoceanography of the southwestern black sea shelf revealed by ostracod assemblages abstract the holocene replacement of ponto caspian ostracod assemblages by mediterranean species is studied in two long composite cores m02 45 a composite of cores m02 45p m02 45 t and m05 03p and m05 50 a composite of cores m05 50p and m05 51g acquired at sites 69 m and 91 m deep on the southwestern black sea shelf composite core m02 45 was collected from the middle shelf and composite core m05 50 was acquired on the distal fringe of the eastern levee of a saline underflow channel emanating from the strait of bosphorus sixteen radiocarbon dates in m02 45 and nine in m05 50 are used to construct age models which show recovery of sediments as old as 12 915 cal yr bp m02 45 site and 12 010 cal yr bp m05 50 site a total of 45 ostracod species are identified in the two cores from 12 000 to 7425 cal yr bp the ostracod assemblage is dominated by ponto caspian species mainly loxoconcha sublepida l lepida and tyrrhenocythere amnicola donetziensis from 7425 to 6315 cal yr bp the assemblage consists of nearly equal abundances of mediterranean species cytheroma variabilis in m02 45 sagmatocythere littoralis in m05 50 and the ponto caspian species after 6315 cal yr bp to the tops of the cores the assemblage is dominated by mediterranean species including palmoconcha agilis carinocythereis carinata hiltermannicythere rubra and pterygocythereis jonesii cluster analysis further subdivides the stratigraphic succession into six bioecozones with different ostracod assemblages the changes in the ostracod assemblages from one bioecozone to the next indicate that progressive environmental changes took place on the southwestern black sea shelf from at least 7500 cal yr bp to the present the first hint of changing conditions at 7500 cal yr bp lags the initial reconnection to the mediterranean sea through the strait of bosphorus by 2000 yr demonstrating that black sea salinity increased slowly and took that long to reach values tolerable to marine ostracod immigrants widespread colonization by mediterranean species took even longer 3000 years from the time of the initial reconnection

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

young danube delta documents stable black sea level since the middle holocene morphodynamic paleogeographic and archaeological implications new radiocarbon and optical dates show that the holocene danube delta started to build out of a black sea embayment 5200 yr ago delta lobe development phases differ by as much as 5 k y from previously proposed ages the new chronology allows for a better understanding of the danube delta paleogeography includ ing the demise of istria the main ancient greek roman city in the region prior reconstructions of sea level in the black sea inferred fluctuations to 15 m in range however stratigraphy of beach ridg es in the delta shows that the relative black sea level for the past 5 k y was stable in the danube delta region within 2 m and 1 5 of the current level hydroisostatic effects related to a proposed catastrophic reconnection of the black sea to the world ocean in the early holocene may have been responsible for the sea level reaching the highstand earlier than estimated by models the new sea level data suggest that submergence at several ancient settle ments around the black sea may be better explained by local fac tors such as subsidence rather than by basin wide sea level fluctuations

reconstruction of late quaternary sea and lake level changes in a tectonically active marginal basin using seismic stratigraphy the gulf of cariaco ne venezuela abstract the gulf of cariaco is a marginal basin located between the cariaco basin and the paria gulf offshore ne venezuela along a system of active right lateral strike slip faults it is connected to the caribbean sea via a shallow 58 m deep sill implying that the gulf was disconnected from the global ocean during eustatic lowstands a dense grid of high resolution reflection seismic profiles has been used to determine the overall tectonic structure of the gulf and to establish the seismic stratigraphy of its sedimentary infill six unconformity bounded seismic stratigraphic units were identified in the upper 200 m of the sedimentary infill detailed seismic stratigraphic and seismic facies analysis allowed defining a series of sedimentary features that can be used as indicators of past sea or lake level in the gulf of cariaco i delta offlap breaks ii evaporites and iii erosional unconformities using accurate measurements of these various indicators at several locations in the gulf and a simple total subsidence model a relative sea lake level history encompassing the last 130 kyr could be reconstructed in periods of connection with the open ocean reconstructed relative sea level correlates well with eustatic sea level in times of disconnection distinct lake level fluctuations occurred which sometimes resulted in total dessication of the gulf lake level fluctuations appear to correlate with major heinrich events stadials and interstadials mis 4 the lgm and the younger dryas were thus identified in the gulf of cariaco sedimentary record the last reconnection to the caribbean sea occurred during mwp1b around 11 5 kyr the very good fit of the cariaco sea lake level curve with the eustatic sea level curves both in terms of amplitude and of timing underscores potential for future paleoclimate research of the sedimentary record contained in this marginal basin despite its active tectonic setting

landform characterization using geophysics recent advances applications and emerging tools abstract this paper presents an overview of the strengths and limitations of existing and emerging geophysical tools for landform studies the objectives are to discuss recent technical developments and to provide a review of relevant recent literature with a focus on propagating field methods with terrestrial applications for various methods in this category including ground penetrating radar gpr electrical resistivity er seismics and electromagnetic em induction the technical backgrounds are introduced followed by section on novel developments relevant to landform characterization for several decades gpr has been popular for characterization of the shallow subsurface and in particular sedimentary systems novel developments in gpr include the use of multi offset systems to improve signal to noise ratios and data collection efficiency amongst others and the increased use of 3d data multi electrode er systems have become popular in recent years as they allow for relatively fast and detailed mapping novel developments include time lapse monitoring of dynamic processes as well as the use of capacitively coupled systems for fast non invasive surveys em induction methods are especially popular for fast mapping of spatial variation but can also be used to obtain information on the vertical variation in subsurface electrical conductivity in recent years several examples of the use of plane wave em for characterization of landforms have been published seismic methods for landform characterization include seismic reflection and refraction techniques and the use of surface waves a recent development is the use of passive sensing approaches the use of multiple geophysical methods which can benefit from the sensitivity to different subsurface parameters is becoming more common strategies for coupled and joint inversion of complementary datasets will once more widely available benefit the geophysical study of landforms three cases studies are presented on the use of electrical and gpr methods for characterization of landforms in the range of meters to 100 s of meters in dimension in a study of polygonal patterned ground in the saginaw lowlands michigan usa electrical resistivity tomography was used to characterize differences in subsurface texture and water content associated with polygon swale topography also a sand filled thermokarst feature was identified using electrical resistivity data the second example is on the use of constant spread traversing cst for characterization of large scale glaciotectonic deformation in the ludington ridge michigan multiple cst surveys parallel to an 60 m high cliff where broad 100 m synclines and narrow clay rich anticlines are visible illustrated that at least one of the narrow structures extended inland a third case study discusses internal structures of an eolian dune on a coastal spit in new zealand both 35 and 200 mhz gpr data which clearly identified a paleosol and internal sedimentary structures of the dune were used to improve understanding of the development of the dune which may shed light on paleo wind directions

geoarchaeology of the ancient and medieval danube delta modeling environmental and historical changes a review abstract the study presents a brief review of the main evolutionary stages of the danube deltaic area according to the most recent discoveries in the field as well as an emphasis on the new delimitating criteria for the hinterland in the ancient 7th century b c 5th century a d and medieval times 14th 18th centuries a d a cartographic delimitation model for the studied settlements hinterlands was created the danube delta is a dynamic interface between the geological history the deltaic morphogenesis and the human occupation the danube delta complex is one of the most important geo political and cultural entities which can be described as a compound geographical unit that provides an exceptional biodiversity although this area has been intensely inhabited during the previous historical periods underlined in the case of several ancient and medieval sources only limited archaeological sites have been identified up to the present and they are affected by the permanent extension and mobility of the danube delta the greek cities of istros histria and orgame argamum colonies established by miletus which later continued their development as roman cities were located in the lagoonal region on the coast the roman fortification of halmyris was situated on the danube delta s southern branch and the small bastion was located on the island called bisericuta two other medieval fortresses were identified heraclea probably a genovese fortress present day enisala and the ottoman fortification of vadu situated respectively at the western and southern limits of the razim sinoie lagoon there are still numerous scientific debates on the origin and evolution of the danube delta and the black sea the specific studies on the recent evolution of the danube s mouths antiquity and the middle ages can provide essential and significant contributions to the habitat s dynamics in relation to the deltaic geomorphology the rapid changes in the shoreline caused a massive exodus of the populations from the areas covered by water the milesian colonies of histria and argamum disappeared because of the rising sea level and because a barrier spit was built in front of the halmyris gulf which caused the formation of the razim sinoie lagoon

subsidence history of australia s southern margin constraints on basin models the subsidence history of australia s southern margin is shown to consist of two distinct tectonic phases and has important implications for models of sedimentary basin formation the first phase is characterized by rapid tectonic subsidence about 50 m m y which lasted for about 25 30 m y during the early cretaceous the period of rapid subsidence represents the rifting phase of margin development this early stage is correlated with associated rifting phenomena faulting and extension of the brittle upper crust formation of grabens and half grabens and the rapid accumulation of volcanogenic detritus otway group the amount of extension 20 50 is estimated from a comparison of observed and modeled tectonic subsidence at several exploratory wells along the margin the model includes uniform extension and thinning of the continental lithosphere a prolonged extensional event followed by simple cooling horizontal and vertical conduction of heat and radioactive heat production by the crust the rift phase may have begun earlier but the most rapid and widespread subsidence occurred during the early cretaceous the end of rapid and widespread subsidence occurred during the early cretaceous the end of rapid subsidence coincides closely with the age of the oldest sea floor spreading magnetic anomaly about 90 ma adjacent to the continent ocean boundary cob the second stage of margin development is the post rift or drift phase a period of much slower rates of subsidence and relative tectonic quiescence subsidence during the post rift stage is modeled as cooling and contraction of extended continental lithosphere estimates of extension and thinning from subsidence modeling agree with seismic refraction measurements of the thickness of continental crust near the cob estimates of extension from the geometry of basement blocks near the cob do not agree with the analysis from subsidence modeling upper crustal extension seems to record only a small proportion of total lithospheric extension alternative or supplementary mechanisms of extension are explored with emphasis on implications from a model that includes localized shear along a lithospheric detachment system

high resolution sr isotopic evolution of black sea water during the holocene implications for reconnection with the global ocean abstract the 10 m thick holocene succession at core site m02 45 41 41 17 n 28 19 08 e 69 m water depth has key advantages for investigation of the sr isotopic evolution of the holocene black sea earlier studies have focussed on thinner successions and coquinas at the m02 45 site augmented by nearby core m05 03p 87sr 86sr determinations on mollusc shells extracted at mostly 10 20 cm depth increments provide a temporal resolution mostly

the timing of the black sea flood event insights from modeling of glacial isostatic adjustment abstract we present a suite of gravitationally self consistent predictions of sea level change since last glacial maximum lgm in the vicinity of the bosphorus and dardanelles straits that combine signals associated with glacial isostatic adjustment gia and the flooding of the black sea our predictions are tuned to fit a relative sea level rsl record at the island of samothrace in the north aegean sea and they include realistic 3 d variations in viscoelastic structure including lateral variations in mantle viscosity and the elastic thickness of the lithosphere as well as weak plate boundary zones we demonstrate that 3 d earth structure and the magnitude of the flood event which depends on the pre flood level of the lake both have significant impact on the predicted rsl change at the location of the bosphorus sill and therefore on the inferred timing of the marine incursion we summarize our results in a plot showing the predicted rsl change at the bosphorus sill as a function of the timing of the flood event for different flood magnitudes up to 100 m these results suggest for example that a flood event at 9 ka implies that the elevation of the sill was lowered through erosion by 14 21 m during and after the flood in contrast a flood event at 7 ka suggests erosion of 24 31 m at the sill since the flood more generally our results will be useful for future research aimed at constraining the details of this controversial and widely debated geological event

the circulation and hydrography of the marmara sea abstract a comprehensive set of data collected during 1986 1992 reveal seasonal and interannual variability in the circulation and hydrography of the marmara sea waters which have contrasting properties and originate from the adjacent basins supply the two layer stratified flows in the sea of marmara turbulent entrainment into the upper layer in the exit region of the bosphorus jet and wind stirring in winter both contribute equally to the basin vertical mixing the upper layer circulation of the marmara sea is determined from adcp measurements and from dynamical calculations based on hydrographic data the mean upper layer circulation is anti cyclonic mainly driven by the southward flowing bosphorus jet in the enclosed domain the bosphorus inflow is well defined except during the periods of low discharge in autumn and winter when the jet becomes weaker and tends to become attached to the west coast near the exit mediterranean water entering from the dardanelles supply the suhalocline layer the negatively buoyant plume of well oxygenated water is the only means of renewal of the deep waters partially compensating for the oxygen consumed by the degradation of organic matter sinking from the upper layer into the lower layer yet the subhalocline waters remain permanently deficient in oxygen as a result of the internal balances of diffusion advection and consumption the depth to which the plume penetrates is a function of the seasonal characteristics of the inflow density modified in the strait and the weak interior stratification

aeolian erosion and sand transport over the mejillones pampa in the coastal atacama desert of northern chile article i nfo the mejillones peninsula in the coastal atacama desert of northern chile is a region in which ocean atmosphere land interactions are particularly strong resulting in enhanced alongshore winds that erode the surface and transport sand particles to the sea because the aeolian particles in the laminated sediments at the bottom of mejillones bay record long term changes in the intensity of prevailing southerly winds it is fundamental to understand aeolian processes such as wind erosion and sand transport to improve paleoceanographic reconstructions the aim of the present study is to characterize the wind erosion process over the flat geomorphology of the northern portion of the mejillones peninsula the mejillones pampa including the influence of wind erosion on the initial particle size distribution and the associated fractionation processes of the mineralogical composition of moving particles through field measurements in addition we test the ability of an existing saltation model mb95 to reproduce the variability of the erosion process during the field experiment soil samples from 17 locations on this flat surface contain significant amounts of highly erodible particles with diameters in the 200 300 m and 100 150 m size ranges aeolian particles collected in bsne sand traps located at different heights near the surface exhibit a bimodal size distribution similar to that of the erodible fraction of the soils the abundance of the fine class increasing with height small stones that have a spatially variable distribution can locally reduce the intensity of wind erosion the mineralogical composition of moving particles is similar to that of the soils with quartz feldspar and calcite as the most important minerals followed by clay minerals gypsum and amphibole a value of u t is calculated for each soil particle size class subsequently the elementary contribution of each size class to the horizontal flux is calculated using white 1979 s equation and the total flux is finally obtained by integration the saltation model successfully reproduces the variability of the wind erosion process during the field experiment but over estimates the vertically integrated mass fluxes measured in situ by two orders of magnitude

modelling the provenance of detritus flushed through the strait of bosphorus turkey during early holocene outflow from the black sea to the world ocean abstract source to sink tracing of very fine sand supplied to a controversial lower holocene deltaic lobe in the northeastern marmara sea was undertaken using sem backscatter mapping and quantitative mineral liberation analysis of very fine sand fractions forty two samples from the kurbagalidere goksu golden horn and riva watersheds and from oligo miocene outcrops along the southwestern black sea coast show that each of these potential sources has a distinct mineralogical fingerprint comparison with 11 samples from the lower holocene delta and 19 samples from the overlying mud drape show that no single source can account for the mineral proportions in the sand fractions of these depositional sinks but a mixed provenance provides good matches for the deltaic lobe quantitative mixing based on 250 000 monte carlo simulations suggests 50 contribution from oligo miocene successions of the southwestern black sea coast and inner shelf 20 contribution from the goksu stream and minor contributions from other sources including the kurbagalidere stream this balance of source contributions continued to supply the holocene mud drape until 6 cal ka after which local sources became more important it is hypothesized that unconsolidated sediment from a number of watersheds was parked along the coast of the neoeuxine lake and in the paleo bosphorus valley during the mis 2 lowstand a rising neoeuxine lake possibly swollen by glacial outburst floods from the altay region of central asia flushed 0 5 km 3 of this sediment through the strait of bosphorus to the deltaic lobe and permitted it to rapidly advance into the marmara sea which at that time was rising 1 m each 100 yr provenance of the lower portion of the holocene mud drape is consistent with continued black sea outflow throughout the deposition of sapropel m1 in the marmara sea

dinoflagellate cysts freshwater algae and fungal spores as salinity indicators in late quaternary cores from marmara and black seas abstract seismic profiles and mollusks have been used to suggest that from 12 500 to 7000 yr bp the black sea was an isolated freshwater lake containing potable water and implying a surface salinity of 24 and that spiniferites cruciformis spiniferites inaequalis peridinium ponticum polykrikos spp and quinquecuspis concreta characterize the lower salinity of the marmara and or black seas the core top data and correlatable down core assemblage changes in time equivalent sapropelic and brown muds show that there is no evidence for differential aerobic decay of dinocysts in the study area the main acritarchs are sigmopollis psilatum concentricystes cf c rubinus and cf acritarch 8 of traverse 1978 all of which are absent from the aegean sea and decrease in abundance with increasing salinity the first two taxa have been reported previously as freshwater species fungal remains show a similar distribution pattern to the freshwater acritarchs indicating their origin from terrestrial environments freshwater chlorococcales are almost confined to the black sea but they have rare occurrences in the aegean indicating long distance transport microforaminiferal linings are abundant in the marmara sea but are absent in deep water of the black sea in the marmara sea mid late holocene assemblages

modes rates and geomorphological consequences of active tectonics in the marmara region nw turkey a critical overview based on seismotectonic field observations abstract the marmara region is a tectonically active belt in northwestern turkey where field evidence of the collusion escape and strike slip tectonics is manifested the effect of tectonics on the modification of coastal and morphological features of nw turkey is although extensive relatively unknown and rarely appreciated active tectonics in the region has normal and reverse forms of dip slip namely uplift and subsidence and strike slip as is plainly demonstrated by the 1999 marmara earthquake sequence along the north anatolian fault naf these tectonic effects are presently related to the geometry of the naf the mode of lateral movement along it and proximity to the fault the 1999 earthquakes provided data indicating that over a return period of about 250 years seismotectonic strike slip movements recur up to 5 m and dip slip movements up to 2 6 m suggesting the rate of tectonics along the naf in the marmara region is on the order of 20 mm a for strike slip and 10 mm a for dip slip movements these rates are sufficiently large to form during the late quaternary prominent features of the landscape in the marmara region

evidence of magmatic co 2 rich fluids in peraluminous graphite bearing leucogranites from deep freeze range northern victoria land antarctica fine grained peraluminous synkinematic leuco monzogranites skg of cambro ordovician age occur as veins and sills up to 20 30 m thick in the deep freeze range within the medium to high grade metamorphics of the wilson terrane secondary fibrolite graphite intergrowths occur in feldspars and subordinately in quartz four main solid and fluid inclusion populations are observed primary mixed co2 h2o inclusions al2sio5 brines in garnet type 1 early co2 rich inclusions brines in quartz type 2 early co2 ch4 up to 4 mol h2o inclusions graphite fibrolite in quartz type 3 late ch4 co2 n2 inclusions and h2o inclusions in quartz type 4 densities of type 1 inclusions are consistent with the crystallization conditions of skg 750 c and 3 kbar the other types are post magmatic densities of type 2 and 3 inclusions suggest isobaric cooling at high temperature 700 550 c type 4 inclusions were trapped below 500 c the skg crystallized from a magma that was at some stage vapour saturated fluids were co2 rich possibly with immiscible brines co2 rich fluids brines characterize the transition from magmatic to post magmatic stages progressive isobaric cooling t 670 c led to a continuous decrease off o 2 can entering in the graphite stability field at the same time the feldspars reacted with co2 rich fluids to give secondary fibrolite graphite decrease oft andf o 2 can explain the progressive variation in the fluid composition from co2 rich to ch4 and water dominated in a closed system in situ evolution the presence of n2 the late stages indicates interaction with external metamorphic fluids

geochemistry of the black sea during the last 15 kyr a protracted evolution of its hydrography and ecology the black sea is a 2200 m deep anoxic marine sea connected to the mediterranean sea via the dardanelles strait marmara sea and the 3 km wide 35 m deep bosphorus strait the biogeochemistry of sediment from the anatolia slope has recorded changes to the hydrography leading up to and following the input of mediterranean water at 9 4 ka 103 yr bp when global sea level rose to the level of the bosphorus sill and high salinity water from the mediterranean began to spill into the then brackish lake the water initially mixed little with the lake water but cascaded to the bottom where it remained essentially isolated for ca 1 6 kyr the time required to fill the basin from the bottom up at its present input rate the accumulation of mo in the sea floor sediments a proxy of bottom water anoxia increased sharply 8 6 ka when bacterial respiration in the bottom water advanced to so42 reduction by the oxidation of organic detritus that settled out of the photic zone its accumulation remained elevated to 5 6 ka when it decreased 60 only to again increase slightly at 2 0 ka the accumulation of corg a proxy of primary productivity increased 3 to 4 fold at 7 8 ka when upward mixing of the high salinity bottom water replaced the then thin veneer of the brackish photic zone in less than 50 yrs from that time onward the accumulation of corg mo and additional trace metals have reflected the hydrography of the basin and bosphorus strait controlled largely by climate

paleoenvironmental changes on the northeastern and southwestern black sea shelves during the holocene abstract four paleoceanographic events are distinguished during the holocene based on changes in macro and microfossil assemblages studied from three sediment cores ak 521 522 2571 from the outer northeast shelf and from core mar02 45 situated on the southwest shelf of the black sea west to the bosphorus the lithology and fossils were previously studied from cores ak 521 and ak 522 and mar02 45 however high resolution ostracod analyses from the ams 14 c dated core ak 2571 allowed for a revision of the taxonomy and paleoecological interpretation of this microfaunal group on the ne shelf downcore changes in the relative abundance of the polyhaline ostracods are found to be contemporaneous in all three cores from the ne shelf as a result centennial millennial scale fluctuations of the bottom water salinity are resolved in the area a broader scale examination of paleoenvironmental changes between the ne and sw shelves is also made and the surface to bottom salinity gradient is discussed an uncalibrated radiocarbon based chronology is used throughout this paper to facilitate comparison with the regional chronostratigraphy of marine transgression and regressions in the black sea the calibrated ages corrected for the changes in reservoir age through the holocene are also provided the first paleoceanographic event is associated with the pulse of mediterranean water previously established at about 9 8 9 3 ka bp this event is clearly observed in the sw region but not on the ne shelf due to a hiatus in the longest core ak 521 the second event is represented on both the ne and sw shelves as a replacement of brackish benthic fauna and surface phytoplankton with marine ones between 8 4 and 6 9 ka bp indicating a gradual increase in salinity the third event is marked by opposing trends in surface and bottom water salinity changes on the ne shelf bottom water salinity rose to modern values by 6 5 ka bp and then decreased within the interval 6 4 5 3 ka bp as recorded by the ostracod assemblages on the sw shelf surface water salinity reached modern values by 5 6 ka bp and remained constant until present day as inferred from the dinoflagellate cyst assemblages the fourth event is marked by a recurring increase in bottom water salinity to modern values indicated by the polyhaline ostracod assemblages at 5 3 ka bp in the ne region after which only minor salinity fluctuations are observed

oscillating quaternary water levels of the marmara sea and vigorous outflow into the aegean sea from the marmara sea black sea drainage corridor abstract detailed interpretation of single channel air gun and deep tow boomer profiles demonstrates that the marmara sea turkey experienced small amplitude 70 m fluctuations in sea level during the later quaternary limited in magnitude by the sill depth of the strait of dardanelles moderate subsidence along the southern shelf and quaternary glacio eustatic sea level variations created several stacked deltaic successions separated by major shelf crossing unconformities which developed during the transitions from global glacial to interglacial periods near the strait of dardanelles a series of sand prone deposits are identified beneath an uppermost holocene transparent mud drape the sandy deposits thicken into mounds with the morphology and cross sectional geometries of barrier islands sand waves and current generated marine bars all cross stratification indicates unidirectional flow towards the dardanelles prior to the deposition of the transparent drape which began 7000 years bp in strong support of the notion that the marmara sea flowed westwards into the aegean sea through the dardanelles at times of deglaciation in northern europe the global sea level curve shows that at 11 000 and 9500 years bp sea level rose to the sill depths of the straits of dardanelles and bosphorus respectively the effect from 11 000 to 9500 years bp was seawater incursion into the marmara sea drowning and formation of algal serpulid bioherms atop lowstand barrier islands and transgression of shelves and lowstand deltas at 9500 years bp glacial meltwater temporarily stored in the black sea lake developed into a vigorous southward flow toward the aegean sea forming west directed sandy bedforms in the western marmara sea and initiating deposition of sapropel s1 in the aegean sea this strong outflow persisted until 7000 years bp after which a mud drape began to accumulate in the marmara sea and euryhaline mediterranean mollusks successfully migrated into a progressively more saline black sea where sapropel deposition began most eastern mediterranean sapropels from s1 to s11 appear to correlate with periods of rising sea level and breaching or near breaching of the bosphorus sill these events are believed to coincide with times of vigorous outflow of low salinity fresh surface waters transiting the black sea marmara sea corridor and ultimately derived from melting of northern european ice sheets

rise and fall of the paratethys sea during the messinian salinity crisis abstract extremely thick evaporite units were deposited during the so called messinian salinity crisis msc 5 96 5 33 ma in a deep mediterranean basin that was progressively disconnected from the atlantic ocean a crucial but still poorly understood component in messinian evaporite models is the connectivity between mediterranean and paratethys i e the former black sea domain inadequate stratigraphic correlations and insufficient age control for paratethys sediments have so far hampered a thorough understanding of hydrological fluxes and paleoenvironmental changes here we present a new chronology for the eastern paratethys by integrating biostratigraphic and paleomagnetic data from mio pliocene sedimentary successions of romania and russia we show that a major flooding event from the mediterranean surged the paratethys basins at the maeotian pontian boundary 6 04 million years ago this indicates that sea level in both mediterranean and paratethys was high at the beginning of the msc we argue in favor of changes in paratethys mediterranean connectivity to initiate the msc in combination with elusive tectonic processes in the gibraltar arc a subsequent fall of paratethyan water level closely coincides to the mediterranean isolation event corresponding in age to the glacial cycles tg12 14 5 60 5 50 myr in the latest messinian a major climate change towards more humid conditions produced a positive hydrological balance and likely a transgression in the paratethys although our stratigraphic resolution cannot exclude a possible relation to the pliocene flooding of the mediterranean here

deltas south of the bosphorus strait record persistent black sea outflow to the marmara sea since 10 ka at the southern exit of the bosphorus strait in the northeastern marmara sea high resolution seismic profiles reveal two lobate progradational delta lobes in modern water depths of v40 65 m the younger delta was active from v10 to 9 ka based on radiocarbon dates of equivalent prodelta deposits and the elevation of its topset to foreset transition the topset to foreset transition climbs in the seaward direction because the delta prograded into a rising sea low abundances of marine fauna and flora in the 10 9 ka interval support a deltaic interpretation there are no rivers in the area that could have fed the delta instead all evidence points to the strait itself as the source of sediment and water when this outflow was strongest v10 6 6 0 ka sapropels accumulated in basinal areas of both the aegean and marmara seas benthic foraminiferal and dinoflagellate cyst data from contemporary deposits elsewhere in the marmara sea point to the continual presence through the holocene of a surface layer of brackish water that we ascribe to this same outflow from the black sea through the bosphorus strait by v9 1 8 5 ka two layer flow developed in the bosphorus strait as global sea level continued to rise and the sediment supply to the younger delta was cut off because the outflowing black sea water ceased to be in contact with the floor of the strait the older delta lobe lies below a prominent lowstand unconformity and is tentatively interpreted to have formed from v29 5 to 23 5 ka oxygen isotopic stage 3 when the marmara sea stood at v355 m and a second sapropel accumulated in deep basinal areas crown copyright 2002 elsevier science b v all rights reserved

anatomy of a compound delta from the post glacial transgressive record in the adriatic sea abstract on the mediterranean continental shelves the post glacial transgressive succession is a complex picture composed of seaward progradations related to sea level stillstands and or increased sediment supply to the coasts and minor flooding surfaces associated with phases of enhanced rates of sea level rise among late pleistocene examples major mid shelf progradations have been related to the short term climatic reversal of the younger dryas event a period during which the combination of increased sediment supply from rivers and reduced rates of sea level rise promoted the formation of progradations up to tens meter thick while the documentation of coastal and subaqueous progradations recording the younger dryas interval is widely reported in literature the model of compound progradation within transgressive deposits has not yet been proposed here we present the documentation of a deltaic system where both delta front sands and related fine grained subaqueous progradations prodeltaic to shallow marine have been preserved the paleo gargano compound delta pgcd formed offshore the modern gargano promontory southern adriatic sea and is composed of a coastal coarse grained delta of reduced thickness and a muddy subaqueous clinoform up to 30 m thick the pgcd probably the first worldwide documentation of a compound delta within the transgressive record provides the opportunity to investigate the processes controlling the formation of a compound delta system during an overall sea level rise and the factors that allowed its preservation the finding of the pgcd provides the opportunity for a comparison with modern worldwide compound systems

paleoclimatic and paleoceanographic conditions leading to development of sapropel layer s1 in the aegean sea abstract sapropel s1 occurs as 25 35 cm thick black weakly laminated muds in aegean sea cores s1 was deposited between 9600 and 6400 yr b p during a period of isotopically depleted and relatively cool surface waters micro faunal and floral data indicate a major reduction in surface waters salinity during the deposition of s1 and oxygen isotopic data show a northerly fresh water source relatively light 13 c org and high pollen spore concentrations in s1 suggest increased influx of terrestrial organic carbon probably supplied by major rivers draining into the northern aegean sea benthic foraminifera indicate high nutrient low oxygen bottom waters for s1 and together with silt sized hematite and manganese coatings suggest that during the deposition of s1 surface sediments were oxic visual and xrd evidence of pyrite in s1 together with enrichments in s cu zn as ni cr and fe suggest that subsurface conditions were sufficiently reducing for so 4 2 reduction to occur probably by diffusion from surface oxic into subsurface anoxic sediments palynomorphs in s1 show large increases in terrestrial pollen and spores with the floral assemblage indicating significant influx from northern european rivers and minor african components associated with increased summer monsoonal rain abundance of dinoflagellates and amorphogen suggests some increase in primary productivity in response to increased influx of humic compounds however there is no evidence of upwelling the clay fraction in s1 shows notable decreases in smectite and kaolinite and reciprocal increases in illite and chlorite the combined data suggested that the evolution of s1 in the aegean sea largely resulted from stagnation of the surface waters during the final disintegration of the continental ice sheets rather than an increase in primary productivity and higher preservation of organic carbon on the sea floor

evolution of the danube deep sea fan since the last glacial maximum new insights into black sea water level fluctuations abstract the danube deep sea fan nw black sea is one of the most developed deep sea sediment depositional systems in europe although the morphology and the architecture have been widely described in the past years little is known about the stratigraphy of this depositional system for the late quaternary this results from the lack of significant stratigraphic markers the scarcity of radiocarbon ages and the difficulty in constraining reservoir ages recent robust quantification of reservoir ages has allowed the construction of a new stratigraphic framework for the black sea from the end of the last glacial period to the holocene thus giving the opportunity to correlate sedimentological and geochemical features previously described on the nw black sea margin with climatic events identified in the northern hemisphere based on this approach we propose an improved chrono lithostratigraphic framework for the danube deep sea fan channel levees since the last glacial maximum we show that the danube deep sea fan was active during the last glacial maximum until the younger dryas early holocene transition ca 11 700 cal a bp when the turbidite activity abruptly terminated in the whole system throughout this period the danube river was the main source of the deep depositional system except between ca 17 200 cal a bp and 15 700 300 cal a bp at that time the deposition of red turbidites in the deep basin concomitant with the deposition of the so called red layers onto the continental shelf and the upper slope emphasises the direct impact of the increased meltwater runoff of the dnieper river as far as the danube deep sea fan some significant changes in the location of the depocentre of the danube deep sea fan occurred through time the main change in depocentre location occurred at ca 28 000 cal a bp with the northward avulsion leading to the formation of the middle channel although the middle and northern channel became the preferential turbidite depocentres after this event the deposition of turbidites has persisted in the southern channel levee until 14 700 cal a bp indicating that the southern channel was definitely not abandoned after the upstream northward avulsion unsurprisingly water level fluctuations and river sediment flux acted as the main forcings on the evolution of the danube deep sea fan based on these results and on the morphology of the danube canyon we propose that i lowstand conditions 110 m prevailed during the last glacial maximum and possibly between 15 700 300 cal a bp and 14 700 cal a bp ii water level ranged from 110 and 70 m between 14 700 and 11 700 cal a bp and iii water level ranged from 70 and 30 m from 11 700 cal a bp and until the reconnection of the black sea lake with the global ocean at ca 9000 cal a bp

black sea lake reservoir age evolution since the last glacial hydrologic and climatic implications abstract chronologies of sediments that document the last glacial history of the black sea lake are hampered by issues relating to reservoir age regulated by basin hydrology reservoir ages represent a tool that could potentially be used to better understand the response of black sea lake hydrology to climate change therefore deciphering reservoir age evolution is crucial both for better constraining the basin chronological framework and for providing new insights into our understanding of black sea lake hydrology by tuning a meaningful new high resolution geochemical dataset obtained from core md04 2790 to a climate reference record here we propose a reliable chronology spanning the last 32 kyr bp the chronology is compared to a large ams radiocarbon dataset n 51 pairs of calendar and radiocarbon ages allowed us to compute reservoir ages and to then reconstruct a high resolution quantitative reservoir age record for the last glacial history of the black sea lake the main factor controlling reservoir ages in lakes is the hard water effect hwe which is regulated by basin hydrology therefore changes in the reconstructed reservoir age record have been qualitatively interpreted in terms of the hydrologic responses of the black sea lake to climate change our results allowed us to determine periods of complete isolation or outflow for the black sea lake during heinrich event 2 he2 and during the last glacial maximum lgm the basin was strictly isolated whereas prior to he2 and during he1 it outflowed into the marmara sea following the onset of the bolling allerod factors other than the hwe are thought to have influenced the reservoir age preventing conclusive interpretations we also determined an undocumented to date phase of black sea lake stratification during the full glacial he2 and lgm our results indicate that reservoir age is a powerful tool for investigating and better understanding past hydrologic changes in lakes and inland seas

early holocene marine flooding of the black sea abstract echo sounding data recorded in the black sea in 1969 imaged a chain of hills 5 to 150 m high at a depth of 2000 2200 m that resemble hills on the lower continental rise like those hills the features in the western black sea may have been created by bottom currents the easterly flowing currents inferred to have formed the hills may be related to a catastrophic flood of the black sea from the sea of marmara 7150 yr ago

mediterranean vegetation lake levels and palaeoclimate at the last glacial maximum the apparent conflict between pollen evidence for widespread artemisia steppe1 6 implying semi arid conditions and geomorphological evidence for high lake levels4 7 11 has produced controversy about the ice age palaeoclimate of the mediterranean region here we use a water balance model12 to predict catchment runoff and a biome model13 to predict vegetation type to reconstruct the palaeoenvironment around lake loannina a type locality for the northern mediterranean region we show that both sets of evidence are compatible with a summer dry winter wet regime with seasonal temperature anomalies similar to those predicted by atmospheric model simulations of the last glacial maximum14 18 the drying effect of the cold north atlantic ocean may have been counteracted in winter by increased storm frequency under a southward shifted jet stream as shown by several atmospheric models16 18

last glacial holocene paleoceanography of the black sea and marmara sea stable isotopic foraminiferal and coccolith evidence multi proxy data and radiocarbon dates from several key cores from the black sea and marmara sea document a complex paleoceanographic history for the last v30 000 yr the marmara sea was isolated from both the black sea and the aegean sea during glacial periods when global sea level lowering subaerially exposed the shallow sills at the straits of bosphorus and dardanelles i e lake stage and reconnected through both straits during interglacial periods when rise of global sea level breached the shallow sills i e gateway stage micropaleontological data show that during the lake stage the surface water masses in both the marmara sea and black sea became notably brackish however during the gateway stages there was a low salinity surface layer and normal marine water mass beneath two sapropel layers are identified in the marmara sea cores sapropels m2 and m1 were deposited between v29 5 and 23 5 ka and v10 5 and 6 0 ka respectively micropaleontological and stable isotopic data show that the surface water salinities were reduced considerably during the deposition of both sapropel layers m2 and m1 and calculation using planktonic foraminiferal transfer functions shows that sea surface temperatures were notably lower during these intervals the presence of fauna and flora with black sea affinities and the absence of mediterranean fauna and flora in sapropels m1 and m2 strongly suggest that communication existed with the black sea during these times a benthic foraminiferal oxygen index shows that the onset of suboxic conditions in the marmara sea rapidly followed the establishment of fully marine conditions at v11 10 5 ka and are attributed to black sea outflow into the marmara sea since 10 5 ka these suboxic conditions have persisted to the present the data discussed in this paper are completely at odds with the flood hypothesis of ryan et al 1997 and ryan and pitman 1999 crown copyright 2002 elsevier science b v all rights reserved

late quaternary lake level record from northern eurasia lake records from northern eurasia show regionally coherent patterns of changes during the late quaternary lakes peripheral to the scandinavian ice sheet were lower than those today but lakes in the mediterranean zone were high at the glacial maximum reflecting the dominance of glacial anticyclonic conditions in northern europe and a southward shift of the westerlies the influence of the glacial anticyclonic circulation attenuated through the late glacial period and the westerlies gradually shifted northward such that drier conditions south of the ice sheet were confined to a progressively narrower zone and the mediterranean became drier the early holocene shows a gradual shift to conditions wetter than present in central asia associated with the expanded asian monsoon and in the mediterranean in response to local monsoon type circulation there is no evidence of mid continental aridity in northern eurasia during the mid holocene in contrast the circum baltic region was drier reflecting the increased incidence of blocking anticyclones centered on scandinavia in summer there is a gradual transition to modern conditions after ca 5000 yr b p although these broad scale patterns are interrupted by shorter term fluctuations the long term trends in lake behavior show a clear response to changes in insolation and glaciation

on the origin of the bosphorus abstract the palaeozoic upper cretaceous basement palaeomorphology of the bosphorus the strait of istanbul bears the evidence of a valley of a palaeostream running to the black sea in the north a palaeobasin deeper than 160 m opening to the sea of marmara in the south and a barrier between these two features this suggest that the northern part of the bosphorus was formed mainly by fluvial activity whereas the southern part developed as a basin by faulting the recent sediment thickness exceeds 130 m in the basin indicating that the southern part of the bosphorus was once essentially depositional rather than an erosional the present form of the bosphorus was established in holocene time by the connection of the basin in the south with the stream in the north the barrier and the stream valley in the north have been deepened by erosion and faulting to form a strait connecting the black sea and the mediterranean

the impact of the late holocene coastal changes on the rise and decay of the ancient city of histria southern danube delta histria istros is one of the earliest milesian colonies founded on the black sea coast during the archaic period 7th c bc its remains are located within what is today the razelm sinoe lagoon system which forms the southern part of the danube delta during its 13 centuries of existence histria experienced an environment favourable for a prosperous economy e g fishery farming grazing pottery marine trades as indicated by numerous archeological finds from both in situ and elsewhere in the black sea and mediterranean sea basins moreover it benefited from a strategic position on an open coast which was easy to defend important environmental changes occurred both during and after the existence of the ancient city and the most significant are related to major shoreline displacement this study reports late holocene coastal landscape changes from the open coast stage to the present day lagoon system based on numerical age determination of the paleoshorelines stratigraphic records by cores in lagoons and beach ridges and topographic surveys a new chronological framework is established which reports younger ages than previously suggested for the coastal morphosedimentary units of the histria region further the findings shed new light upon the evolution of the southern part of the danube delta the results point to the development of an ancient deltaic lobe dunav lobe 2000 1300 bp associated with the southernmost danube distributary which was situated 10 20 km north of the settlement the lobe was subsequently reworked by waves providing sediments which were accumulated downdrift southward as a continuous beach ridge plain saele chituc in front of the city leading to its isolation from the sea the abandonment of histria 7th c ad coincides with the decoupling of the city from the open coast as a consequence of the shoreline progradation the new beach ridge plain saele chituc is affected by intense neotectonic movements which led to the recent drowning of its central part and the formation of sinoe lagoon the same processes affected the downdrift part of the dunav lobe and histria and nuntasi lakes the new sea level curve obtained for the histria region shows relative stability within the last four millennia with oscillations within 0 to 2 m of the current level this contradicts the concept of a marine regression phanagorian which is suggested to have occurred during the 1st millennium bc however a few areas containing archeological remains are currently below sea level owing to local neotectonics

seasonal interannual and mesoscale variability of the black sea upper layer circulation derived from altimeter data 1 topex poseidon and ers altimeter data comprising the period from may 1992 to may 1999 are assimilated into a shallow water model for providing a dynamically consistent interpretation of the sea surface height variations and estimation of the temporal and spatial characteristics of the upper layer circulation in the black sea these 7 year long observations offer a new capability for interpretation of major transient and quasi permanent features of the upper layer circulation the instantaneous flow fields involve a complex eddy dominated system with different types of structural organizations in which the eddies and the gyres of the interior cyclonic cell interact continuously among themselves and with meanders and filaments of the rim current the circulation possesses a distinct seasonal cycle whose major characteristic features repeat every year with some year to year variability an organized two gyre winter circulation system disintegrates gradually into a series of interconnecting eddies in the summer and autumn months which are also characterized by more pronounced and complex mesoscale activity in the peripheral flow system our analyses suggest a revised schematic circulation picture of the major quasi permanent and recurrent elements of the black sea

seismic stratigraphy of late quaternary deposits from the southwestern black sea shelf evidence for non catastrophic variations in sea level during the last 10 000 yr abstract detailed interpretation of single channel seismic reflection and huntec deep tow boomer and sparker profiles demonstrates that the southwestern black sea shelf formed by a protracted shelf edge progradation since the miocene pliocene five seismic stratigraphic units are recognized unit 1 represents the last phase of the progradational history and was deposited during the last glacial lowstand and holocene it is divided into four subunits subunit 1a is interpreted as a lowstand systems tract 1b and 1c are interpreted as a transgressive systems tract and subunit 1d is interpreted as a highstand systems tract the lowstand systems tract deposits consist of overlapping and seaward prograding shelf edge wedges deposited during the lowstand and the subsequent initial rise of sea level these shelf edge wedges are best developed along the westernmost and easternmost segments of the study area off the mouths of rivers the transgressive systems tract deposits consist of a set of shingled shore parallel back stepping parasequences deposited during a phase of relatively rapid sea level rise and include a number of prograded sediment bodies including barrier islands beach deposits and thin veneers of seismically transparent muds showing onlap onto the flanks of older sedimentary features a number of radiocarbon dates from gravity cores show that the sedimentary architecture of unit 1 contain a detailed sedimentary record for the post glacial sea level rise along the southwestern black sea shelf these data do not support the catastrophic refilling of the black sea by waters from the mediterranean sea at 7 1 ka postulated by ryan pitman major shimkus maskalenko jones dimitrov gorur sakinc yuce mar geol 138 1997 119 126 ryan pitman touchstone book 1999 319 pp and ballard coleman rosenberg mar geol 170 2000 253 261

holocene and late glacial palaeoceanography and palaeolimnology of the black sea changing sediment provenance and basin hydrography over the past 20 000 years abstract the elemental geochemistry of late pleistocene and holocene sediments of the black sea recovered in box cores from the basin margins and a 5 m gravity core from the central abyssal region of the basin identifies two terrigenous sediment sources over the last 20 kyrs one source region includes anatolia and the southern caucasus the second region is the area drained by rivers entering the black sea from eastern europe alkali metal al and heavy light rare earth element ratios reveal that the relative contribution of the two sources shifted abruptly every few thousand years during the late glacial and early holocene lacustrine phase of the basin the shifts in source were coeval with changes in the lake level as determined from the distribution of quartz and the heavy mineral hosted trace elements ti and zr the geochemistry of the abyssal sediments further recorded a sequence of changes to the geochemistry of the water column following the lacustrine phase when high salinity mediterranean water entered the basin beginning 9 3 kyrs bp bottom water that had been oxic throughout the lake phase became anoxic at approximately 8 4 kyrs bp as recorded by the accumulation from the water column of several redox sensitive trace metals mo re u the accumulation of organic carbon and several trace nutrients cd cu ni zn increased sharply ca 0 4 kyrs later at 8 0 kyrs bp reflecting an increase of primary productivity its increase was coeval with a shift in the dinoflagellate ecology from stenohaline to euryhaline assemblages during this profound environmental change from the lacustrine to the marine phase the accumulation rate of the lithogenous sediment fraction decreased as much as 10 fold in response to the rise of the water level in the basin from a low stand ca 9 3 ka to its current level

holocene sedimentation in the southwestern black sea interplay between riverine supply coastal eddies of the rim current surface and internal waves and saline underflow through the strait of bosphorus abstract an extensive grid of high resolution huntec deep tow seismic reflection profiles 9150 line km complemented by 72 gravity cores and 25 piston cores reveals that the sedimentary architecture of the southwestern black sea above a prominent shelf crossing unconformity is characterized by three allostratigraphic units allounits 1b 1c 1d separated by two regional unconformities and their correlative conformities 1 and 2 a fourth allounit 1a occurs as patchy remnants between the unconformity and a deeper pleistocene erosional unconformity 0 the chronology is established using 56 radiocarbon dates in five key piston cores the unconformity developed as a ravinement surface during the transgression associated with the transition from the last glacial maximum to holocene thus defines the base of the holocene successions allounit 1b is bounded at its base and top by the and 1 unconformities correlative conformities it was deposited between 12 5 and 7 4 cal ka and shows a notably patchy but widespread distribution across the southwestern shelf allounit 1c is bounded at its base and top by the 1 and 2 unconformities correlative conformities it was deposited between 7 4 and 5 3 cal ka allounit 1d accumulated above the 2 unconformity correlative conformity and was deposited since 5 3 cal ka interpretation of radiometrically dated cores and several detailed regional maps reveal that the widespread occurrence of 12 5 7 4 cal ka deposits allounit 1b across the middle and outer shelf provides no possibility for a holocene evaporative drawdown to a lowstand elevation of 120 m at 9 4 cal ka as suggested by yanchilina et al 2017 instead the volume of detritus in allounit 1b can only be explained if base level was sufficiently high to allow major distant rivers in bulgaria and romania e g kamchiya danube to contribute mud through long distance marine transport along a submerged shelf there is no evidence in any cores which sample allounit 1b that the sites were located in limans rather than on a transgressed shelf which had been flooded by post glacial meltwater and enhanced river runoff as the climate became more humid in the early holocene a prolonged stillstand at the spill depth controlled by the sill in the strait of bosphorus is confirmed by the elevation of a drowned recurved spit downdrift from cape emine bulgaria the development of the subaqueous unconformities correlative conformities 1 and 2 was facilitated by storm induced wave erosion transport bypass and erosion under the rim current and its anticyclonic eddies and possibly breaking internal waves volumetrics based on isopach maps and pre industrial sediment discharge rates of various rivers entering the western and southwestern black sea suggest that the total sediment yields of bulgarian and turkish rivers can only account for 13 14 of the total holocene succession allounits 1b 1d and that major input from the danube river via along shelf long distance transport must have occurred through the entire holocene

late quaternary co seismic sedimentation in the sea of marmara s deep basins the deep northern part of the sea of marmara northwestern turkey is composed of several aligned actively subsiding basins which are the direct structural and morphological expression of the north anatolian fault s northern branch the last 20 kyr of their sedimentary fill lacustrine before 12 kyr bp have been investigated through giant piston coring onboard r v marion dufresne marmacore cruise 2001 and chirp subbottom profiler onboard r v atalante during marmarascarps cruise 2002 especially during the lacustrine stage the infilling of the deep basins tekirda central kumburgaz and cinarcic basins up to 1250 m depth was dominated by turbidites with coarse mixed siliciclastic and bioclastic basal part intercalated in hemipelagic type finegrained calcareous and slightly siliceous clays often especially in the thickest ones the turbidites show strong segregation and a sharp boundary between coarse part and suspendedload part in the central basin 8 m of a unique sedimentary event include a 5 to 8m thick homogenite well imaged on seismic profiles the latter is interpreted as related to a major possibly triggered tsunami effect as described in the eastern mediterranean by kastens and cita 1981 in the marine holocene upper part of the sedimentary fill repeated to and from structures affecting silt or fine sand are evidencing seiche like effects and thus earthquake triggering detailed correlations between two deep coring sites 1250 and 1200 m indicate more than 100 overthickening in the deepest one this implies specific processes of distribution of terrigenous input by dense hyperpycnal currents high kinetic energy seiche effect complex reflections on steep slopes the peculiar sedimentary infilling of the sea of marmara s central basin and by extrapolation of the whole set is tentatively interpreted as a direct consequence of the strong seismic activity the imprint of the latter is more obvious prior to the base of the holocene as environmental conditions favoured marginal accumulation especially on the southern shelf of large amounts of erosion products available for mass wasting

late quaternary sedimentation and high resolution sequence stratigraphy of the east texas shelf the shelf margin deltas of the area show a complex pattern of progradation and aggradation that varies from one delta to the next this complexity is due predominantly to the different response of systems with different sediment supplies to fifth order eustatic fluctuations before we understood these autocyclic effects attempts at relating seismic stratigraphic changes to the oxygen isotope curve our proxy for sea level change were unsuccessful

catastrophic flooding of the black sea abstract decades of seabed mapping reflection profiling and seabed sampling reveal that throughout the past two million years the black sea was predominantly a freshwater lake interrupted only briefly by saltwater invasions coincident with global sea level highstand when the exterior ocean lay below the relatively shallow sill of the bosporus outlet the black sea operated in two modes as in the neighboring caspian sea a cold climate mode corresponded with an expanded lake and a warm climate mode with a shrunken lake thus during much of the cold glacial quaternary the expanded black sea s lake spilled into to the marmara sea and from there to the mediterranean however in the warm climate mode after receiving a vast volume of ice sheet meltwater the shoreline of the shrinking lake contracted to the outer shelf and on a few occasions even beyond the shelf edge if the confluence of a falling interior lake and a rising global ocean persisted to the moment when the rising ocean penetrated across

the effects of the north anatolian fault zone on the latest connection between black sea and sea of marmara abstract the development of the strait of istanbul is also one of the principal results of the tectonics which led to the evolution of the north anatolian fault zone nafz in the marmara region 3 7 ma ago high resolution seismic profiles from the marmara entrance of the strait of istanbul show a folding which occurred after the deposition of the parallel reflected tyrrhenian sediments over the tyrrhenian strata a fondoform zone of a deltaic sequence and marine sediments of the latest sea level rising are present these sediments also display syn depositional folding this situation implies that a local compressional stress field was created over the area probably since the wurm glacial age this recent variation of the tectonic regime in the northern shelf of the sea of marmara may indicate a significant change in the development of the nafz through the sea of marmara this variation of evolution of the nafz affected the latest development of the strait of istanbul via clockwise rotation of the istanbul and kocaeli peninsulas by right lateral shearing between two zone bounding faults this rotation has led to the development of nne ssw left lateral faults in the strait of istanbul and local compressional and tensional areas explaining the compressional structures seen in the southern entrance of the strait of istanbul therefore the latest mediterranean black sea connection was established by means of the sufficient deepening of the bosphorus channel by a variation in the evolution of nafz through the sea of marmara

reconstruction of holocene precipitation patterns in europe using pollen and lake level data abstract lake level data can be used to refine palaeoclimate reconstructions based on pollen data this approach is illustrated for the european holocene estimates of p pet precipitation minus potential evapotranspiration were first inferred from modern pollen analogues the pollen based estimates were then compared with the status of lakes within a 5 radius analogues with p pet anomalies inconsistent with the lake level changes were rejected the constrained sets of analogues were used to estimate continental scale patterns of annual mean temperature and annual precipitation at 3000 yr intervals estimated temperature anomalies differed only slightly from the unconstrained reconstructions estimated precipitation anomalies however showed improved spatial coherence and increased regional contrast and were occasionally reversed in sign the effect of the constraint was to impose a rational selection among almost equally similar modern pollen analogues with similar temperatures but widely varying moisture regimes the resulting maps showed clear spatially coherent patterns of change in precipitation as well as temperature suitable for comparison with climate model results further improvement of these maps will become possible as a more extensive coverage of lake level data is obtained

abrupt drainage cycles of the fennoscandian ice sheet continental ice sheets are a key component of the earth s climate system but their internal dynamics need to be further studied since the last deglaciation the northern eurasian fennoscandian ice sheet fis has been connected to the black sea bs watershed making this basin a suitable location to investigate former ice sheet dynamics here from a core retrieved in the bs we combine the use of neodymium isotopes high resolution elemental analysis and biomarkers to trace changes in sediment provenance and river runoff we reveal cyclic releases of meltwater originating from lake disna a proglacial lake linked to the fis during heinrich stadial 1 regional interactions within the climate lake fis system linked to changes in the availability of subglacial water led to abrupt drainage cycles of the fis into the bs watershed this phenomenon raised the bs water level by 100 m until the sill of the bosphorus strait was reached flooding the vast northwestern bs shelf and deeply affecting the hydrology and circulation of the bs and probably of the marmara and aegean seas

controversy over the great flood hypotheses in the black sea in light of geological paleontological and archaeological evidence abstract legends describing a great flood are found in the narratives of several world religions and the biblical account of noah s flood is the surviving heir to several versions of the ancient mesopotamian flood myth recently the story of the biblical deluge was connected to the black sea together with the suggestion that the story s pre mesopotamian origins might be found in the pontic basin ryan w b f pitman iii w c 1998 noah s flood the new scientific discoveries about the event that changed history simon and schuster new york based on the significance of this flood epic in the judeo christian tradition popular interest surged following publication of the idea currently two great flood scenarios have been proposed for the black sea 1 an early holocene event caused by catastrophic mediterranean inflow at 7 2 ky bp initial hypothesis of ryan et al 1997 an abrupt drowning of the black sea shelf marine geology 138 119 126 or 8 4 ky bp modified hypothesis of ryan et al 2003 catastrophic flooding of the black sea annual review of earth and planetary science 31 525 554 and 2 a late pleistocene event brought on by caspian influx between 16 and 13 ky bp chepalyga a l 2003 late glacial great flood in the black sea and caspian sea gsa annual meeting and exposition 2 5 november 2003 seattle usa p 460 both hypotheses claim that the massive inundations of the black sea basin and ensuing large scale environmental changes had a profound impact on prehistoric human societies of the surrounding areas and both propose that the event formed the basis for the biblical great flood legend this paper attempts to determine whether the preponderance of existing evidence sustains support for these great floods in the evolution of the black sea based upon established geological and paleontological data it finds that the late pleistocene inundation was intense and substantial whereas the early holocene sea level rise was not between 16 and 13 ky bp the late neoeuxinian lake the late pleistocene water body in the pontic basin pre dating the black sea increased rapidly from 14 to 50 m below the present level of the black sea then rose gradually to 20 m by about 11 ky bp at 11 10 ky bp the younger dryas it dropped to 50 m when the black sea re connected with the sea of marmara at about 9 5 ky bp inflowing mediterranean water increased the black sea level very gradually up to 20 m and in so doing it raised the salinity of the basin and brought in the first wave of mediterranean immigrants these data indicate no major drawdown of the black sea after the younger dryas and they do not provide evidence for any catastrophic flooding of the black sea in the early holocene in addition available archaeological and paleoenvironmental evidence from the pontic region reveal no recognizable changes in population dynamics between 14 and 6 ky bp that could be linked to an inundation of large magnitude dolukhanov p shilik k 2006 environment sea level changes and human migrations in the northern pontic area during late pleistocene and holocene times in yanko hombach v gilbert a s panin n dolukhanov p m eds the black sea flood question changes in coastline climate and human settlement springer dordrecht pp 297 318 stanko v n 2006 fluctuations in the level of the black sea and mesolithic settlement of the northern pontic area in yanko hombach v gilbert a s panin n dolukhanov p m eds the black sea flood question changes in coastline climate and human settlement springer dordrecht pp 371 385 more specifically mesolithic and early neolithic archaeological data in southeastern europe and ukraine give no indications of shifts in human subsistence or other behavior at the time of the proposed catastrophic flood in the early holocene anthony d 2006 pontic caspian mesolithic and early neolithic societies at the time of the black sea flood a small audience and small effects in yanko hombach v gilbert a s panin n dolukhanov p m eds the black sea flood question changes in coastline climate and human settlement springer dordrecht pp 345 370 dergachev and dolukhanov 2006 the neolithization of the north pontic area and the balkans in the context of the black sea floods in yanko hombach v gilbert a s panin n dolukhanov p m eds the black sea flood question changes in coastline climate and human settlement springer dordrecht pp 489 514

paleo tsushima water and its effect on surface water properties in the east sea during the last glacial maximum revisited abstract the semi enclosed deep marginal east sea is known by limited sill flow and low sea surface salinity during the last glacial maximum lgm when sea level was about 130 m lower than the present level although three straits the tsugaru the soya and the tartar with shallower than 130 m sills were completely closed the korea strait with a maximum sill depth of 140 m seems to have persisted as a partial connection to the east sea allowing a sill flow the volume transport at the korea strait during the lgm is estimated at approximately 0 3 1 1 1012 m3 yr by using bathymetry seismic reflection profiles and current data the low sea surface salinity has been explained by the east china sea coast water ecscw and high precipitation however the existing geological observations indicate that precipitation was reduced in the glacial east sea the high resolution numerical simulation results predict that evaporation 2 16 mm day exceeded precipitation 1 43 mm day further suggesting net evaporation evaporation minus precipitation rates 0 2 1012 m3 yr over the lgm east sea this signifies that the precipitation was not the factor lowering surface paleosalinity and that the paleo tsushima water carried a huge amount of freshwater from the ecscw than previously expected the calculated surplus evaporation 0 2 1012 m3 yr and sill flow 0 3 1 1 1012 m3 yr are not identical but they could be oceanographically considered as similar the comparison between both values implies that most of the throughflow ultimately escaped the east sea through the evaporation process during the lgm the regional sea level in the almost isolated east sea might be largely maintained by a rough balance between incoming throughflow and outgoing evaporation during the lgm the geographic restriction due to lowered sea level and lower surface salinity by limited vertical mixing in the glacial east sea are analogous to modern oceanographic features in the black sea

late glacial to holocene benthic foraminifera in the marmara sea implications for black sea mediterranean sea connections following the last deglaciation benthic foraminifera were studied from four gravity cores that penetrated holocene marine sediments in the marmara sea morphogroup and assemblage analyses reveal that the holocene sea level rise did not result in a catastrophic flooding event as proposed by w b f ryan and others whereby well oxygenated saline mediterranean waters rapidly inundated a low lying low salinity black sea lake at v7 15 ka popularly known as the noah s flood hypothesis rather the benthic foraminiferal data confirm the hypothesis that the dardanelles sill was breached by the mediterranean at v12 ka allowing saline waters to penetrate the marmara sea these saline waters reached the level of the bosphorus sill at v9 5 ka but were unable to penetrate into the black sea until after v9 1 ka because of the persistent strong outflow of brackish to fresh water from the black sea the initial colonisation of the marmara sea by benthic foraminifera is essentially synchronous with the re establishment of marine connections through the dardanelles strait at v12 ka by v10 ka ammonia dominated faunas developed on the strait exit delta v1 at the southern end of the bosphorus and at v9 1 ka the appearance of fully marine species documents the establishment of a more stratified water column over v1 finally the increase in abundance of planktonic foraminifera at the southern exit of the bosphorus after v6 1 ka reflects a decreased volume of outflow water from the black sea quantitative analysis of benthic foraminiferal morphogroups reveals that the oxygen content of subhalocline water was low below v1 5 ml l throughout the holocene and the occurrence of sapropel sediment in the deeper part of the basin suggests bottom waters may have been anoxic at times after v4 5 ka an increase in benthic foraminiferal oxic morphotypes suggests a reduction in black sea outflow and weakening of the halocline the strong and persistent stratification of the water column in the marmara sea throughout the holocene is entirely incompatible with the noah s flood hypothesis 2002 elsevier science b v all rights reserved

late glacial holocene paleoclimatic and paleoceanographic evolution of the aegean sea micropaleontological and stable isotopic evidence abstract late glacial to holocene paleoclimatic and paleoceanographic changes are examined using records of calcareous and organic walled marine microfossils pollen and terrestrial spores and oxygen isotope data in cores from the aegean sea basins planktic foraminiferal coccolith and dinoflagellate data show that the late glacial holocene transition in the region was associated with a large warming of surface water mediterranean based paleotransfer functions for planktic foraminifera show a 5 10 c increase in surface water temperature from 14 000 to 9600 yr b p estimates of surface water oxygen isotopic composition 18 o w derived from planktic foraminiferal oxygen isotopic and transfer function data indicate that this warming was associated with a 2 0 to 2 5 reduction in 18 o w transfer function results indicate corresponding 1 0 to 1 5 salinity reductions for this tim ca 6400 9600 yr b p throughout the aegean sea pollen dinoflagellate and isotopic data show that the early holocene excess fresh water originated from rapid melting of the northern european and siberian ice sheets supplied primarily from the black sea by the opening of bosphorus and dardanelles channels during the post glacial sea level rise and supplemented by major rivers entering the aegean sea continuous outflow of fresh water into the aegean sea provided a low salinity surface lid preventing the ventilation of the deep water benthic foraminifera shows a major turn over that indicates low dissolved oxygen however bottom waters were not anoxic sapropel level s1 resulted from a combination of stagnant deep water in isolated depressions increased terrigenous organic matter and periods of high primary productivity as indicated by pollen and dinocysts respectively the surface water temperature and salinity reached present day values at 6400 yr b p with little subsequent change despite the major deforestation onshore