meltwater floods into the black and caspian seas during heinrich stadial 1 abstract deglaciation of the eurasian ice sheet dispensed vast amounts of meltwater laden with red brown clay into black and caspian sea s freshwater lakes between 16 350 and 15 400 calendar years bp the arriving sediment had a mineral composition and strontium neodymium isotope signatures 87sr 86sr and end consistent with the crystalline bedrock that lay beneath the ice sheet as opposed to sources from landscapes crossed by the rivers that carried meltwater to the lakes the magnitude and rapidity of the shifts of 87sr 86sr and 18o in shells of ostracods and mollusks an eight fold increase in sediment accumulation rate and a plunge of 1250 14c years in the radiocarbon reservoir age indicate a volume of meltwater sufficient to have replaced most or all of the pre existing lake water if the release of 25 000 km3 of water from the caspian into the black sea s new euxine lake was abrupt by judging the magnitude of erosion in the floor of the manych strait spillway this event qualifies as a megaflood deeply scoured furrows channel floor bars and swaths of mounds 5 20 km in length and 5 20 m in height are reminiscent of scabland landscapes the meltwater is coincident with heinrich stadial 1 when the alpine and eurasian ice sheets re advanced and temperatures of the black sea s lake surface remained cold sand grains within the red brown clay indicate they were transported by lake surface ice

lateglacial and holocene sea level changes in semi enclosed seas of north eurasia examples from the contrasting black and white seas abstract a comparison of the black and white seas which differ in their tectonic glacial and climatic history but which share a strong dependence upon limited water exchange with the world ocean represents an opportunity for the identification of major factors controlling sea level changes during the lateglacial and holocene and for the correlation of these changes existing data were critically analyzed and compared with the results of geological geomorphological and palaeohydrological studies obtained by the present authors during the past two decades we conclude that glacioeustatic processes played a major role in relative sea level changes on most coasts of both areas however along several coastlines other factors overwhelm glacioeustasy during some time intervals in the black sea water level rose from its minimum position 100 120 m at 18 17 ka bp to 20 30 m at nearly 9 ka bp in the white sea the decreasing trend in relative sea level is well illustrated on the kola peninsula and in karelia subject to glacioisostatic emergence a drastic sea level fall from 15 to 25 m occurred with the drainage of glacial lakes in the eastern white sea 12 5 9 5 ka bp the black and white sea histories changed drastically in the early holocene or in the beginning of the middle holocene 9 5 7 5 ka bp due to the intrusion of water from the mediterranean and the barents seas respectively during this period the white sea developed under the strong influence of the formation of ice shelves and dead ice blocks retreating glaciers as well as of glacioisostatic and related processes the black sea history however was determined by water exchange with the mediterranean via the shallow dardanelles and bosporus straits outflow from the black sea 10 9 5 ka bp and inflow from 9 7 5 ka bp according to various data and partially by river discharge variations caused by climatic changes on the russian plain the hypothesis of a catastrophic sea level rise from 120 150 to 15 20 m nearly 7550 calendar years bp is not supported by our data water intrusion from the mediterranean was fast but not catastrophic in the black sea periods of high sea levels after the intrusion of mediterranean waters are dated from four sedimentary complexes vityazevian kalamitian dzhemetian and nymphaean from nearly 7 5 7 6 5 5 4 5 and 2 2 1 7 ka bp respectively a fluctuating pattern of sea level change was established in the white sea after the drainage of proglacial lakes and intrusion of ocean waters at the end of the early holocene nearly 8 5 8 2 ka bp major periods of sea level rise in the white sea are dated from the late boreal early atlantic 8 5 7 5 ka bp late atlantic 6 5 5 2 ka bp middle subboreal 4 5 4 ka bp and middle subatlantic 1 8 1 5 ka bp fluctuations of relative sea level during the middle and late holocene were possibly on the order of several meters from 2 3 to 2 3 m in the black sea and from 3 5 to 2 3 m in the white sea lower estimates of regressive stages are principally derived from archaeological data on ancient settlements in tectonically submerging deltaic areas and cannot be regarded as reliable palaeohydrological analysis does not indicate that intensive 15 25 m or greater sea level fluctuations were present in the black sea or in the white sea during the middle and late holocene instead such analysis provides independent evidence to support the argument that significant differences in water level between the black sea and the mediterranean could not be maintained for an extended period of time

geochemical variation in microstructural shell layers of the southern quahog mercenaria campechiensis implications for reconstructing seasonality abstract shells of the northern and southern quahogs mercenaria mercenaria and mercenaria campechiensis respectively from paleontological and archaeological deposits have been used to reconstruct climate environmental conditions and ecological relationships seasonal fluctuations in temperature and salinity are recorded in shell carbonate as variations in 18 o and 13 c values and sr ca ratios however these environmental proxies have not yet been calibrated for m campechiensis previous geochemical studies of quahog shells focused on the outer prismatic layer as an ecological archive the outer layer is often not preserved in fossil and archaeological shells moreover recent innovations in microsampling techniques allow high resolution sampling of the middle cross lamellar layer this study tests whether outer prismatic and middle cross lamellar layers record similar variations in 18 o and 13 c values and sr ca ratios in modern shells of m campechiensis and whether profiles are similar among individuals the last 2 years of shell growth from three individuals 6 7 and 9 years old collected alive near bokeelia southwest florida were microsampled for geochemical analyses 18 o varies seasonally relative to translucent summer and opaque winter growth increments variation of 18 o from outer and middle layers are identical within and among shells however the oldest individual did not preserve the most positive values represented in the two younger shells 13 c from both layers are similar within shells although the outer layer is more variable and the range of values varies somewhat among individuals sr ca ratios from the outer and middle layers within shells do not track each other well and profiles among individuals are different to evaluate whether a seasonal signal was present sr ca ratios were compared to 18 o values there was no co variation within the outer layer in any of the shells therefore this layer should be avoided when using sr ca ratios as a temperature proxy the middle layer from the 6 year old shell showed no co variation the 7 year old shell exhibited a moderate negative co variation r 2 0 55 p r 2 0 72 p 18 o and environmental interpretations made using 13 c values should be treated with caution

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

abrupt chemical weathering increase across the permian triassic boundary previous studies have suggested a variety of causes for the end permian extinction event including a bolide impact flood basalt volcanism methane clathrate dissociation or some combination of catastrophic processes one common feature of these hypotheses is the prediction of an enhanced earliest triassic greenhouse new high resolution geochemical results from graphite peak antarctica support an abrupt increase in chemical weathering in the earliest triassic among otherwise genetically similar paleosols of similar provenance relative to the latest permian paleosols the earliest triassic paleosol exhibits greater leaching greater accumulation of immobile rees and evidence of lower soil po2 with no evidence of an erosional unconformity between the paleosols which are separated by 15 cm stratigraphically these results support a rapid shift perhaps 10 000 years to an earliest triassic greenhouse and a role for methane release in the extinction event and its aftermath

multicentennial scale hydrological changes in the black sea and northern red sea during the holocene and the arctic north atlantic oscillation 1 paleoenvironmental proxy data for ocean properties eolian sediment input and continental rainfall based on high resolution analyses of sediment cores from the southwestern black sea and the northernmost gulf of aqaba were used to infer hydroclimatic changes in northern anatolia and the northern red sea region during the last 7500 years pronounced and coherent multicentennial variations in these records reveal patterns that strongly resemble modern temperature and rainfall anomalies related to the arctic oscillation north atlantic oscillation ao nao these patterns suggest a prominent role of ao nao like atmospheric variability during the holocene beyond interannual to interdecadal timescales most likely originating from solar output changes

late glacial to holocene climate and sedimentation history in the nw black sea abstract gravity cores from the continental slope in the northwestern black sea were studied using high resolution stable isotope grain size and xrf scanning data the measurements provide a 30 000 years ams 14c dated record of variations in the hydrological regime of the black sea and give insight into changing paleoenvironments in the surrounding areas stable climatic conditions during the last glacial maximum were followed by a series of meltwater pulses most likely originating from the scandinavian ice sheet between 18 000 and 15 500 yr bp 1 this meltwater input rose the level of the caspian sea to a point that caspian water could spill into the black sea via the manych depression north of the caucasian mountains high frequency oscillations in the xrf data during this period suggest a probable link to the arctic climate regime later during the bolling allerod and the early holocene prevailing high temperatures led to authigenic calcite precipitation through increased phytoplankton activity interrupted by the younger dryas and the 8200 yr bp cold event with dominant clastic sedimentation

environmental controls on the stable isotopic composition of mercenaria mercenaria potential application to paleoenvironmental studies 1 we have investigated the environmental controls of seasonally resolved records of oxygen and carbon isotopes of modern mercenaria mercenaria bivalves collected live from five coastal sites along the east coast of north america seasonal profiles of 18o and 13c obtained by subsampling the incremental growth layers of aragonite were compared with in situ historical records of temperature and salinity we show that m mercenaria 18o profiles track accurately the seasonal variations of water temperature and that variations in growth rates do not affect the shell 18o values growth rates are strongly reduced or interrupted below water temperatures ranging from 8 to 10 c implying that only bivalves sampled in tropical areas track the full amplitude of seasonal variations although further measurements of water 18o and a better understanding of seasonal variations of the water 18o salinity relationships are necessary mercenaria mercenaria bivalves appear to precipitate their shell close to isotopic equilibrium whereas the amplitude of the seasonal profiles of 18o reflects variations in water temperature the annual average 18o decreases with latitude reflecting the trend of rainfall and riverwater 18o with latitude over the northern american continent

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

changes in coastline positions during the holocene in the shelf of the northwestern black sea the first evidence for the reconnection of the black sea with the mediterranean sea are euryhaline mollusc species that appear in the bottom sediments lacustrine conditions existed over the larger part of study area at the beginning of the holocene early holocene beds are characterized by a wide distribution of continental facies e g lacustrine marshy and alluvial the lacustrine phase was followed by a marine phase and the transition occurred around ca 8 9 8 5 ka bp the holocene was marked by a gradual increase of mytilus sp shells in sediments reconstructions of coastline positions during the holocene in the northwestern black sea shelf are presented extensive sampling of the study area during several decades allowed the acquisition of a comprehensive data base for paleogeographic reconstructions positions of ancient coastlines are discussed analysis of relief features lithological composition and bottom sediments distribution and faunal complexes allowed identification of paleofacies in the northwestern part of the black sea facial and paloegeographic maps of the holocene discrete time intervals such as the bugazian from ca 10 5 10 to 8 9 8 5 ka bp the vityazevian from ca 8 9 8 5 to 7 1 6 2 ka bp the kalamitian from ca 7 1 6 2 to 4 1 4 0 ka bp and the dzhemetinian from ca 4 1 4 0 to present are presented dating of the sediments is based on uncalibrated radiocarbon determinations study of the granulometry of sediments provided evidence that supports the proposed ancient coastline positions the samples from the cores recovered from different facial zones enabled the characterization of sedimentological environments for each time interval the position of the early holocene coastal sediments is marked out on the level of modern isobaths approximately from 25 to 35 m in the range of time from ca 8 9 8 5 to 7 1 6 2 ka bp the coastline was located at depths from 20 to 25 m the position of the coastline which existed from ca 7 1 6 2 to 4 1 4 ka bp is allocated on the level of modern isobaths from 0 to 15 m comparison of the various positions of the coastline and their facies changes through time indicates that the holocene transgression had a progressively and oscillatory course

paleoenvironments in russkaya gavan fjord nw novaya zemlya barents sea during the last millennium the 6 m long sediment core asv 987 was collected from the deep part of the glaciated russkaya gavan fjord at the northwestern coast of novaya zemlya barents sea in 1997 r v akademik sergei vavilov the core was investigated for lithology grain size coarse debris organic carbon foraminifera macrobenthic remains and stable isotopes in foraminiferal tests age control was provided by seven ams 14 c ages the recovered sedimentary section spans approximately 800 years from ca 1170 ad the proxy records reveal variations in sedimentation processes bioproductivity glacier front position seaice conditions and the hydrographic regime in the fjord these characteristics are interpreted in terms of regional and global climatic changes during the last millennium we distinguish four stages in the development of sedimentary environments in russkaya gavan which generally correspond to major climatic events the medieval warm period mwp the early and late phases of the little ice age lia and recent warming the most pronounced change in sedimentation regime occurred at the onset of the lia ca 1400 presumably due to the advance of a glacier into the fjord subsequent evolution of sedimentary environments included stabilization and retreat of the glacier front the most recent facies are interpreted to indicate a change towards warmer conditions d 2004 elsevier b v all rights reserved

hydraulic calculations of postglacial connections between the mediterranean and the black sea a series of simple hydraulic calculations has been performed to examine some of the questions associated with the reconnection of the black sea to the mediterranean through the turkish strait system during the holocene ryan et al s catastrophic flood scenario whereby the erosive power of the marine in fluxes initiated after eustatic sea level reached the sill depth opened up the bosphorus allowing saline water to pour into the black sea and filling it on a short time scale is examined the calculations show that although it might be possible to fill the palaeo black sea within the order of a decade a 1 2 year filling time scale is not physically possible a hydraulic model is also used to examine the more traditional connection hypothesis of near continuous freshwater outflow from the black sea with a slowly increasing saline inflow from the mediterranean beginning around 8 9 kyr bp the model considers two forms for the structure of the bosphorus a shallow sill as seen today and a deep sill associated with no sediments filling the 100 m gorge above the bedrock in the strait sensitivity experiments with the hydraulic model show what possible strait geometric configurations may lead to the black sea reaching its present day salinity of 18 psu salinity transients within the black sea are shown as a function of time providing for values that can be validated against estimates from cores to consider a deep non sediment filled bosphorus 100 m deep the entry of mediterranean water into the sea of marmara after 12 0 kyr bp is examined a rapid entry of marine water into the sea of marmara is only consistent with small freshwater fluxes flowing through the turkish strait system smaller than those of the present day by a factor of at least 4 such a small freshwater flux would lead to the salinification of the black sea being complete by an early date of 10 2 9 6 kyr bp thus the possibility of a deep bosphorus sill should be discounted

constraints on black sea outflow to the sea of marmara during the last glacial interglacial transition new cores from the upper continental slope off romania in the western black sea provide a continuous high resolution record of sedimentation rates clay mineralogy calcium carbonate content and stable isotopes of oxygen and carbon over the last 20 000 yr in the western black sea these records all indicate major changes occurring at 15 000 12 800 8400 and 7100 yr before present these results are interpreted to reflect an evolving balance between water supplied by melting glacial ice and other river runoff and water removed by evaporation and outflow the marked retreat of the fennoscandian and alpine ice between 15 000 and 14 000 yr is recorded by an increase in clays indicative of northern provenance in black sea sediments a short return toward glacial values in all the measured series occurs during the younger dryas cold period the timing of the first marine inflow to the black sea is dependent on the sill depths of the bosporus and dardanelles channels the depth of the latter is known to be 80 5 m which is consistent with first evidence of marine inundation in the sea of marmara around 12 000 yr the bedrock gorge of the bosporus reaches depths in excess of 100 m relative to present sea level though it is now filled with sediments to depths as shallow as 32 m two scenarios are developed for the connection of the black sea with the sea of marmara one is based on a deep bosporus sill depth effectively equivalent to the dardanelles and the other is based on a shallow bosporus sill less than 35 m in the deep sill scenario the black sea s surface rises in tandem with the sea of marmara once the latter connected with the aegean sea and black sea outflow remains continuous with inflowing marine water gradually displacing the freshwater in the deep basin the increase in the 18 o of mollusk shells at 12 800 yr and the simultaneous appearance of inorganic calcite with low 18 o is compatible with such an early marine water influx causing periodic weak stratification of the water column in the shallow sill scenario the black sea level is decoupled from world sea level and experiences rise and fall depending on the regional water budget until water from the rising sea of marmara breaches the shallow sill in this case the oxygen isotope trend and the inorganic calcite precipitation is caused by increased evaporation in the basin and the other changes in sediment properties reflect climate driven river runoff variations within the black sea watershed the presence of saline ponds on the black sea shelf circa 9600 yr support such evaporative drawdown but a sensitive geochemical indicator of marine water one that is not subject to temperature salinity or biological fractionation is required to resolve whether the sill was deep or shallow

stable isotopic variation in pteropods and atlantids from north pacific sediment traps abstract to determine their usefulness in paleoenvironmental studies and to better understand isotopic equilibrium in biogenic aragonite carbon and oxygen isotopic analyses were performed on six species of pteropod and two species of atlantid collected with free drifting sediment traps from the north pacific ocean where the depth habitat of a species is constrained enough to permit estimation of the ambient temperature and water 18o the isotopic compositions of the shells are close to aragonite water 18o equilibrium with the ambient water none of the fauna are in 13c equilibrium with the dissolved bicarbonate assuming aragonite water equilibrium fractionation the 18o values of the shells provide reasonable average depths of shell growth the distribution is as follows 1 shallow water species 125 m l bulimoides small the 18o variation within specimens of c columnella a large easily sectioned species is complex with no clear record of seasonality however some minor seasonal effects are observed the 13 c values within specimens consistently show a 1 2 decrease from the caudal septum to the aperture perhaps reflecting increased incorporation of metabolic co2 with age

is the abrupt drowning of the black sea shelf at 7150yrbp a myth abstract sedimentological and chronostratigraphic studies of the coastal plain sediments of the black sea near the sakarya river turkey and seismic stratigraphic survey of the shelf sediments off this river s mouth were carried out the results indicate that just prior to its flooding by the mediterranean waters at about 7200 yr bp the black sea was a fresh water lake emptying its waters into the sea of marmara the water level of this lake was about 18 m lower than the present sea level but above the 35 m sill depth of the bosphorus this finding contradicts with ryan et al 1997a ryan et al 1997b hypothesis that the black sea lake water level was more than 100 m below the sill depth of the bosphorus and that the drowning of the black sea shelf at 7150 yr bp was abrupt

geological and mineralogical study of co rich ferromanganese crusts from a submerged atoll in the tuamotu archipelago french polynesia the tuamotu archipelago in french polynesia is a co rich ferromanganese crust province the nodco i survey 1986 provided detailed data on co rich crusts in this environment through the exploration of a restricted zone in the vicinity of niau island on the southern flank of the archipelago this flat zone is a fossil atoll which under the action of subsidence and tectonic movements has collapsed to a water depth of 1000 m the plateau is partially filled with coralline sediments outcrops of ferromanganese crusts associated with rare nodules and slabs are located on the inner side of the coral reef which bounds the ancient lagoon the successive episodes of plateau history have been recorded in the different growth periods of the ferromanganese crusts the crusts nodules and slabs belong to the same morphological mineralogical and geochemical family cobalt contents vary from 0 7 to 1 3 the highest values belong to the thinnest ferromanganese crusts which are located on the flanks of the plateau average ni contents are about 0 5 and cu contents about 0 1 pt contents vary from 0 2 to 1 3 ppm platinum and co are enriched in the outermost oxide zone of the crusts poorly crystallized mno2 is the dominant mineralogical phase cobalt enrichment seems to be related to mno2 particle size the greatest contents are located in the finest material where the particle size is less than 0 1 m cobalt rich crusts of the niau zone have the same characteristics as the co rich crusts from the equatorial north pacific they differ in original setting the reefal environment in the niau zone is superficial overlying a volcanic substrate

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

the holocene history of the ne black sea and surrounding areas an integrated record of marine and terrestrial palaeoenvironmental change here we present an almost complete and integrated holocene record of marine and terrestrial palaeoenvironmental change from the ne shelf of the black sea a dinoflagellate cyst record used to recon

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

pollen stratigraphy of late quaternary cores from marmara sea land sea correlation and paleoclimatic history marine pollen analysis is an important tool for paleoclimatic reconstruction of regions like the eastern mediterranean and near east where few onshore sites provide long pollen records first a compilation was made of core top data from the eastern mediterranean to blackseas to map regional variations in modern marine pollenspore concentrations these data show a strong linkbetween pollen spore concentrations and sea surface salinity with minima of 5 grains g in the southern mediterranean and maxima of 160 000 grains g in the blacksea despite under representation of some forest and herbaceous vegetation indicators e g fagus and pistacia variations in species composition of the marine assemblages correspond closely with the distribution of regional vegetation zones and can be used as proxies for spatial differences in seasonal and total temperature and rainfall pollen spore assemblages in five cores from the marmara sea with multiple ages ranging from 33 550 to 1990 yr bp and one holocene core from southeastern blacksea were used to compile a late quaternary marine pollen stratigraphy these data were then compared with eastern mediterranean onshore reference sites in order to reconstruct a vegetation and paleoclimate history for the blacksea aegean corridor from the pleniglacial interval to present five marine pollen zones are recognized pz 5 v33 6 24 ka corresponds to the late wu rm pleniglacial pz 4 v24 13 ka spans the late glacial maximum lgm pz 3 v13 10 2 ka includes the allero d younger dryas glacial interglacial transition pz 2 10 2 4 ka marks the early holocene interglacial warm wet interval and pz 1 covers the latest holocene colonization phase which may also have been cooler and drier using the steppe forest index of traverse 1975 it is shown that the only intervals of severely dry conditions occurred briefly during the lgm and its transition during most of the pleniglacial and all of the postglacial time precipitation versus evaporation rates were sufficiently high to permit persistence of oro mediterranean forest vegetation furthermore there is no evidence for environmental conditions in the blacksea marmara region that would have encouraged pastoral or agricultural settlement in the littoral region prior to the bronze age commencing 4600 years ago crown copyright a 2002 elsevier science b v all rights reserved

holocene sea level oscillations and environmental changes on the eastern black sea shelf abstract a multi proxy study of four sediment cores from the eastern caucasian black sea shelf revealed five transgressive regressive cycles overprinted on the general trend of glacioeustatic sea level rise during the last 11 000 14c yr these cycles are well represented in micro and macrofossil assemblages sedimentation rates and grain size variations the oldest recovered sediments were deposited in the neoeuxinian semi freshwater basin 10 500 9000 14c yr bp and contain a caspian type mollusk fauna dominated by dreissena rostriformis low 18o and 13c values are measured on this species the first appearance of marine mollusks and ostracodes from the mediterranean is established in this part of the black sea at 8200 14c yr bp i e about 1000 2000 yr later than the appearance of marine microfossils in the deeper part of the sea the early holocene bugazian to vityazevian condensed section of shell and shelly mud sediments with at least two hiatuses represent a high energy shelf edge facies it contains a transitional assemblage representing a mixture of caspian and mediterranean fauna this pattern suggests a dual flow regime via the bosphorus after 8200 14c yr bp caspian species disappear and oligohaline species decrease in abundance during the vityazevian prekalamitian cycle later during the middle to late holocene low sea level stands are characterized by shell layers whereas silty mud with various mollusk and ostracode assemblages rapidly accumulated during transgressions restricted mud accumulation as well as benthic faunal composition and abundance suggest high energy and well ventilated bottom water during low sea level stands a trend of 18o enrichment in mollusk shells points to an increase in bottom water salinity during the vityazevian to kalamitian transgressions 7000 to 5700 14c yr bp due to a more open connection with the mediterranean while a pronounced increase in polyhaline species abundance is established during the kalamitian to djemetean transgressions 6400 to 2700 14c yr bp however the composition of the faunal assemblage indicates that bottom water salinity never exceeded modern values of 18 20 psu

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

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

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