occurrence stratigraphy and geochemistry of late quaternary tephra layers in the aegean sea and the marmara sea abstract several discrete tephra layers occur in 2 5 10 3 m long cores from the aegean sea whereas a single tephra is identified in 3 5 9 7 m long cores from the marmara sea major and trace element data on these tephras delineate eight distinct groups the geochemical data and multivariate statistics allow the correlation of the tephra layers with six previously described marine tephras from the eastern mediterranean sea potential terrestrial sources are suggested for the others the chronostratigraphy of the tephra layers was established using several radiocarbon dates and the oxygen isotope stratigraphy from two long piston cores four widespread tephra layers occur within the upper quaternary sediments of the aegean sea the two youngest widespread tephra layers were derived from the santorini volcano of south central aegean sea z2 the minoan eruption ca 3 6 ka and y2 the cape riva eruption ca 21 7 ka the y2 tephra is also identified in three piston cores from the marmara sea the two older widespread tephra layers originated from the eruptions which emplaced the campanian ignimbrite of the italian volcanic provinces i e the y5 tephra ca 39 3 ka and from the nisyros volcano of the southeastern aegean sea the consistent occurrence of the nisyros tephra below the y5 tephra confirms similar findings in a lake core on the island of lesbos linear extrapolations using the oxygen isotope stratigraphy suggest an age of 42 44 ka for the nisyros eruption three additional tephra layers with a limited regional distribution are identified in the aegean sea cores two of these tephras originated from the yali volcano of the southeastern aegean sea and from the aeolian islands i e x1 tephra a series of six mugearite tephra beds in the south skiros basin is interpreted as a set of redeposited turbidites

eastern mediterranean sapropel s1 interruption an expression of the onset of climatic deterioration around 7 ka bp we discuss the palaeoclimatic interpretation of unprecedented high resolution micropalaeontological studies of shortterm 2 to 4 centuries interruptions within early holocene organic rich layer sapropel s1 from the eastern mediterranean results for cores from the adriatic and aegean seas that contain double s1 sapropels indicate that these interruptions which are centred roughly around 7000 years 14 cnc bp are genuine and related to climatic deterioration this interpretation is endorsed by a coeval dry event recorded in terrestrial records and indications of climatic deterioration affecting human migration patterns and early societies in egypt the presence of sapropel interruptions in the two major source areas of deep water for the entire eastern mediterranean likely implies that similar intervals may be found throughout the basin provided that sedimentation rates and sampling resolutions allow the detection of events with a duration of only several centuries moreover our results show that the sapropel mode of circulation comprises a delicate balance between reduced ventilation and enhanced productivity which is easily disturbed through surface water cooling triggering a short time of improved deep water ventilation 1999 elsevier science b v all rights reserved

clay minerals in late glacial and holocene sediments of the northern and southern aegean sea different source areas oceanography and climate regimes influenced the clay mineral assemblages and grain size distribution of two sediment cores from the north and south aegean sea during the last glacial and the holocene in the north aegean sea clay mineral composition is mainly controlled by sea level evolution melting of southeastern european glaciers and establishment of the connection between the black sea and aegean sea the long term development of clay mineral assemblages in the south aegean sea reflects changes in the nile discharge and african dust input at this site the establishment of pluvial conditions in the nile catchment during the early to middle holocene resulted in a substantial rise in smectite illite ratios in the late holocene stepwise aridification of the southern borderlands caused an increase in windblown sediment material and a decrease in nile suspended material the clay mineral records exhibit periodic millennial scale fluctuations in the north aegean sea the changes are centred at a period of 1 3 1 8 ka and can be attributed to short term climate and weathering changes in the northern borderlands the changes in the south aegean sea are centred at periods of 3 2 4 3 1 9 2 4 and 1 3 1 7 ka reflecting short term changes in wind strength and northeast african hydrology 2007 elsevier b v all rights reserved

the influence of changing orbital parameters and surface boundary conditions on climate simulations for the past 18 000 years abstract general circulation model experiments at 3000 year intervals for the past 18 000 years were made to estimate the magnitude timing and pattern of the climatic response to prescribed changes of orbital parameters date of perihelion axial tilt eccentricity and glacial age lower boundary conditions ice sheets land albedo sea ice and sea surface temperature the experiments used the community climate model ccm of the national center for atmospheric research ncar the response of monsoon circulations and tropical precipitation to the orbitally produced solar radiation changes was much larger than the response to changes of glacial age boundary conditions the continental interior of eurasia was 2 4 k warmer in summer and summer monsoon precipitation of north africa south asia was increased by 10 20 between 12 000 and 6000 yr bp before present when perihelion occurred during northern summer rather than in winter as now and the earth s axial tilt was larger than now southern hemisphe

the mesolithic neolithic transition in southern iberia new data and a review of historiographic information from neolithic sites of the malaga and algarve coasts southern iberian peninsula and from the maghreb north africa reveal the existence of a neolithic settlement at least from 7 5 cal ka bp the agricultural and pastoralist food producing economy of that population rapidly replaced the coastal economies of the mesolithic populations the timing of this population and economic turnover coincided with major changes in the continental and marine ecosystems including upwelling intensity sea level changes and increased aridity in the sahara and along the iberian coast these changes likely impacted the subsistence strategies of the mesolithic populations along the iberian seascapes and resulted in abandonments manifested as sedimentary hiatuses in some areas during the mesolithic neolithic transition the rapid expansion and area of dispersal of the early neolithic traits suggest the use of marine technology different evidences for a maghrebian origin for the first colonists have been summarized the recognition of an early north african neolithic influence in southern iberia and the maghreb is vital for understanding the appearance and development of the neolithic in western europe our review suggests links between climate change resource allocation and population turnover

deglacial warming of the northeastern atlantic ocean correlation with the paleoclimatic evolution of the european continent abstract isotopic micropaleontologic and pollen analyses of deep sea cores from the bay of biscay and the northeastern atlantic ocean show that the deglacial warming of this oceanic area was closely correlated with the paleoclimatic evolution of the adjacent european continent temperatures were at least as warm as those of today in the bay of biscay between 13 300 and 11 000 b p coinciding with the combined bolling allerod warm continental events a major spread of polar water occurred between 11 000 and 10 000 b p during this event which coincides with the younger dryas continental cold event marine temperatures were almost as low as those of the last glacial maximum the final deglacial warming of the norteastern atlatntic ocean occurred during the following 3000 yr

northern levantine and adriatic quaternary planktic foraminifera reconstruction of paleoenvironmental gradients rohling e j jorissen f j vergnaud grazzini c and zachariasse w j 1993 northern levantine and adriatic quaternary planktic foraminifera reconstruction of paleoenvironmental gradients mar micropaleontol 21 191 218 a detailed study of the planktic foraminiferal records of three cores recovered near crete shows very consistent changes unfortunately the record of t87 2 13g our shallowest core is bioturbated too much for detailed comparisons but it can still be used to discuss the general trends the mutual record of the other two cores t87 2 20g and t87 2 27g extends back to about 125 000 yr b p principal components analyses performed on the combined records of t87 2 20g and t87 2 27g yield two axes that can be interpreted paleoecologically namely a temperature axis and an annual stability axis the latter is a measure of stratification within the euphoric layer in this study we consider t87 2 20g and t87 2 27g to be reference cores for the eastern mediterranean subsequently we interprete the faunal variation in two cores from the adriatic sea in 68 5 and in 68 9 containing records extending back to 15 000 and 18 000 yr b p in the context of these reference cores this is done by calculating scores of the adriatic records along the two relevant pca axes derived from the northern levantine records also cluster analyses of the adriatic and northern levantine records are compared on the average the adriatic sea appears to have been considerably colder than the region around crete during the past 18 000 years this temperature difference was largest during the pleniglacial and only small during the holocene we found no distinct expression of a younger dryas cooling event in the adriatic records neither on our pca axis nor in the oxygen isotope record this contradicts previous paleoclimatic reconstructions based mainly on paleobotanical evidence which suggests that the younger dryas event greatly influenced circum mediterranean areas as yet we have no ready explanation for this discrepancy low annual stability values dominate both the pleniglacial and the holocene intervals of the adriatic records this suggests that homothermal conditions were as prevalent in the adriatic euphoric layer at pleniglacial times as they are at present in the present day adriatic homothermal conditions are associated with deep convection and subsequent eastern mediterranean deep water emdw formation and therefore our data suggest that emdw formation was as effective at pleniglacial times as it is at present high annual stability values in the transitional interval from 12 700 to 9600 yr b p in the adriatic records are suggestive of low emdw formation rates at that time in combination with high productivity throughout the eastern mediterranean which has previously been inferred from the planktic foraminiferal record these low emdw formation rates may have preconditioned the eastern mediterranean for sapropel formation

a stratigraphically controlled multiproxy chronostratigraphy for the eastern mediterranean 1 an accelerator mass spectrometry ams 14c dated multiparameter event stratigraphy is developed for the aegean sea on the basis of highly resolved centimeter to subcentimeter multiproxy data collected from four late glacial to holocene sediment cores we quantify the degree of proportionality and synchroneity of sediment accumulation in these cores and use this framework to optimize the confidence levels in regional marine radiocarbon based chronostratigraphies the applicability of the framework to published lower resolution records from the aegean sea is assessed next this is extended into the wider eastern mediterranean using new and previously published high resolution data from the northern levantine and adriatic cores we determine that the magnitude of uncertainties in the intercore comparison of ams 14c datings based on planktonic foraminifera in the eastern mediterranean is of the order of 240 years 2 se these uncertainties are attributed to synsedimentary and postsedimentary processes that affect the materials dated this study also offers a background age control that allows for vital refinements to radiocarbon based chronostratigraphy in the eastern mediterranean with the potential for similar frameworks to be developed for any other well studied region

late quaternary paleoclimate in the eastern mediterranean region from stable isotope analysis of speleothems at soreq cave israel abstract the eastern mediterranean continental paleoclimate during the past 25 000 years was determined by a high resolution petrographic stable isotopic and age study of speleothems from soreq cave israel 18o 13c trends indicate that all speleothems older than 7000 yr formed under conditions that differ from those of today the period from 25 000 to 17 000 yr b p was characterized by the highest 18o and 13c values which indicate deposition at temperatures of 12 16 c annual rainfall of 300 450 mm and vegetation typical of a mixed c3 c4type from 17 000 to 10 000 yr b p deglaciation in northern europe 18o values dropped progressively correlative with warming 2 3 c and a gradual increase in precipitation a simultaneous decrease in 13c gives a range expected for c3 type vegetation this period also shows significant 18o and 13c spikes which are correlatable with global events e g heinrich events and the younger dryas stade the speleothems that grew between 10 000 and 7000 yr b p have a unique petrography showing irregular thin laminae of various colors and much detritus they have the lowest 18o corresponding to 1000 mm rain coupled with the highest 13c caused by flooding events which stripped the soil cover from 7000 to 1000 yr b p conditions became closer to those of today this study demonstrates that global events which were recognized in northern europe and north africa are also evident in the eastern mediterranean and are reflected principally by large changes in the rainfall rate

early seafaring activity in the southern ionian islands mediterranean sea abstract this paper summarises the current development in the southern ionian islands kefallinia and zakynthos prehistory and places it within the context of seafaring archaeological data from the southern ionian islands show human habitation since middle palaeolithic going back to 110 ka bp yet bathymetry sea level changes and the late quaternary geology show that kefallinia and zakynthos were insular at that time hence human presence in these islands indicates inter island mainland seafaring seafaring most likely started some time between 110 and 35 ka bp and the seafarers were the neanderthals seafaring was encouraged by the coastal configuration which offered the right conditions for developing seafaring skills according to the voyaging nurseries and autocatalysis concepts

evaluation of palaeoenvironmental changes during the last 18 000 years in the myrtoon basin sw aegean sea abstract high resolution last glacial maximum to holocene palaeoenvironmental changes corresponding to a time interval between 200 and 500 years are examined in the myrtoon basin in the sw aegean sea using the abundance variation in foraminifera and pollen in relation to accelerator mass spectrometry 14 c dating and limited oxygen isotope data foram abundance variation shows that from 18 ka to the late glacial holocene boundary at around 10 5 to 9 5 ka the sea surface was cold during this period two intervals of relatively high and low sea surface temperature sst were observed the first high sst occurred at around 14 2 ka whereas the second high sst was centred at around 12 8 ka and appears to correspond to the termination 1a event the first low sst was centred at around 13 7 ka and the second low sst occurred between 11 8 and 10 8 ka the former event may correspond to the heinrich 1 event and the latter to the younger dryas chronozone the holocene started with a sharp warming of sea surface water reaching present day levels and probably associated with a reduction in salinity the formation of the sapropel sequence in the myrtoon basin started at about 10 ka about the same time as the sapropel formation in the other aegean basins which means that the environmental conditions became suitable for the formation of sapropels in the aegean about 800 years earlier than in the adriatic ionian and levantine basins within the sapropel sequence there are two high organic carbon corg content sublayers s 1 a 9 7 9 ka and s 1 b 7 3 6 9 ka separated by a lower corg content sublayer indicating variation in the oceanographic and climatic conditions prevailing in the area during the sapropel sequence formation the depositions of s 1 a and s 1 b coincide with an increase in sst increased temperature and enhanced fresh water inputs from the outflowing rivers in to the aegean sea which later was supplemented by the overflowing of the black sea lowered the sea surface density and reduced the vertical water masses circulation resulting in reduced bottom water ventilation the reduction of o 2 supply to the seabed in combination with increased fluxes of terrigenous and or marine organic matter were responsible for the creation of dysoxic to anoxic conditions in the seabed which led to the formation of sapropel s 1 the sapropel formation ended at 5 2 ka and about the same time the sst attained present day levels during the last glacial maximum and late glacial periods the pollen source area was providing a suitable environment for the growth and survival of arboreal taxa the source area was apparently ice free and was characterized by sufficient humidity and non lethal low temperatures probably only a few degrees colder than present day

model data comparison for the 8 2 ka bp event confirmation of a forcing mechanism by catastrophic drainage of laurentide lakes abstract to improve our understanding of the mechanism behind the 8 2 ka bp cooling event we compare proxy evidence with climate model simulations in which the thermohaline ocean circulation is perturbed by a freshwater pulse into the labrador sea both the proxy data and model results show a cooling that is mainly concentrated in the north atlantic region ranging from more than 5 c cooling in the nordic seas to about 0 5 1 c over europe and less than 0 5 c over the subtropical north atlantic data and model also indicate a weakening of the summer monsoon and generally a drier circum north atlantic over the south atlantic ocean the model simulates a slight warming mostly less than 0 5 c which falls within the uncertainty of proxy data and thus could not be confirmed to examine in detail the structure of the 8 2 ka bp event we also compare the modeled climatological evolution at two locations with high quality records revealing a generally consistent picture the good model data agreement confirms the hypothesis that the 8 2 ka bp event was forced by a freshwater induced weakening of the thermohaline circulation other forcings are unlikely since they would result in an alternative geographical distribution and expression of the climate response

the nature distribution and origin of a sapropelic layer in sediments of the silicia basin northeastern mediterranean a sapropelic layer with organic carbon contents of 1 0 1 5 in contrast to the usual 0 2 0 5 of adjacent normal basin sediments is found to be widespread in sediment cores collected from the cilicia basin northeastern mediterranean the horizon is thought to be equivalent to the s1 sapropel of other workers it is finely laminated with no evidence of bioturbation has a very markedly low magnetic susceptibility and contains a significantly higher content of pollen and plant debris than is found in the normal basin sediment the stable oxygen and carbon isotope values suggest that the layer formed during post glacial climatic warming when fresh nutrient rich surface water flowed into the cilicia basin from the surrounding land to produce a stratified water mass which allowed the development of anoxic bottom waters the distribution of the sapropelic layer indicates that anoxic conditions extended to within approximately 350 m of sea level during deposition a depth shallower than previously recorded in the eastern mediterranean

foraminiferal ecozones a high resolution proxy for the late quaternary biochronology in the central mediterranean sea the planktic foraminiferal distribution identified in 60 cores collected in different basins of the mediterranean sea allowed to establish an ecostratigraphical scheme which provides a very important tool for the biochronological subdivision of the uppermost quaternary we identified a succession of ten ecozones during the last 23 ka in the tyrrhenian basin and eight ecozones in the adriatic sea during the last 15 ka the ecozones boundaries have been calibrated by 14c ams radiometric data and by the stable oxygen isotope record the chronological framework defined by the successive bioevents shows a very high resolution millenary scale and evidences that the changes in the planktic microfauna occurred more or less synchronously throughout the central mediterranean sea differences due to different oceanographic settings of the basins do not affect the general distributional pattern of planktic foraminifera

deciphering late quaternary land snail shell δ18o and δ13c from franchthi cave argolid greece this paper investigates the stable isotopic composition from late pleistocene holocene 13 to 10 5 cal ka bp shells of the land snail helix figulina from franchthi cave greece it explores the palaeoclimatic and palaeoenvironmental implications of the isotope palaeoecology of archaeological shells at the time of human occupation of the cave modern shells from around the cave were also analysed and their isotopic signatures compared with those of the archaeological shells the carbon isotope composition of modern shells depicts the consumption of c3 vegetation shell oxygen isotopic values are consistent with other mediterranean snail shells from coastal areas combining empirical linear regression and an evaporative model the 18os suggest that modern snails in the study area are active during periods of higher relative humidity and lower rainfall 18o probably at night late glacial and early holocene 18os show lower values compared to modern ones early holocene 18os values likely track enhanced moisture and isotopic changes in the precipitation source by contrast lower late glacial 18o could reflect lower temperatures and 18op compared to the present day shell carbon isotope values indicate the presence of c3 vegetation as main source of carbon to late glacial and early holocene snails

palynology of sapropelic layers from the marmara sea palynological records of the sediments from the deep basins of the marmara sea revealed four palynological zones indicating the changing climatic conditions during late glacial to holocene the lower two zones were defined by the high abundance of artemisia and chenopodiaceae that suggest the climate of the source area was cold and arid however the establishment of mediterranean warm and wet climate and corresponding regression of continental aridity were shown by the decreasing chenopodiaceae and increasing pollen grains of humid type vegetation in zone c the highest total pollen with the dominance of quercus identifies the deglaciation and coincides with the formation of sapropelic layers in the marmara sea the warmer and humid condition of deglaciation was indicated with diversified moisture demanding deciduous and coniferous pollen grains in zone b these pollen assemblages and their distribution pattern indicate that the source area was warm and wet during the deposition of sapropelic layers in the marmara sea and also reflect signals of black sea origin

sedimentation processes in the eastern mediterranean sea during the late glacial and holocene revealed by end member modelling of the terrigenous fraction in marine sediments we present grain size distributions of the terrigenous fraction of two sediment cores from the southeast levantine sea sl112 and the northern aegean sea sl148 spanning the time interval from the late glacial to the present end member modelling of the grain size distribution allows discriminating between aeolian and fluvial transport of the sediments and helps to infer palaeoenvironmental conditions in the source areas sedimentary and depositional processes during the late glacial and holocene were controlled by climatic variations of both the northern high latitudes and the african climate system the sedimentation at site sl112 off israel is dominated by the suspension load of the river nile and aeolian dust from the sahara variations in grain size reflect the early to mid holocene climate transition from the african humid period to recent arid conditions this climate change was gradual in contrast to the abrupt humidity change documented in western saharan records this implies a successive decrease in nile river sediment supply due to a step wise aridification of the headwaters the grain size data of sl112 show a humidity maximum at 5 kyr bp coincident with a regionally restricted wet phase in the levantine sea the sediments at the north aegean site sl148 consist of riverine particles and low amounts of aeolian dust probably derived from south european sources and with probably minor saharan influence the sedimentation processes are controlled by climate conditions being characterized by enhanced deposition of dust during the cold and dry glacial period and by decreased aeolian influx during the temperate and humid holocene

late pliocene to early pleistocene astronomically forced sea surface productivity and temperature variations in the mediterranean abstract principal component analysis of late pliocene to early pleistocene planktonic foraminiferal abundances from the mediterranean yielded two significant components which represent first order approximations for sea surface productivity and temperature this interpretation is confirmed by the good fit between the score plots and sea surface productivity and sea surface temperature proxy records based on selected eutrophic and temperature sensitive species using present day habitat characteristics spectral analysis revealed significant peaks in the orbital frequency bands of the spectrum suggesting that variations in sea surface productivity and temperature are controlled by the quasi periodic variations in the earth s orbit precession forced variations are reflected primarily in sea surface productivity and to a lesser degree in sea surface temperature maxima in sea surface productivity and temperature in this frequency band occurred at times of sapropel formation the sea surface productivity maxima can be explained by an increased input of river borne nutrients and by the shoaling of the pycnocline and the associated intensification of the deep chlorophyll maximum dcm layer precession forced variations in sea surface temperature are not related to glacial cycles since this frequency component is almost completely absent in ice volume proxy records for this time interval sapropel bound sea surface temperature maxima presumably reflect periods of maximum insolation during the northern hemisphere summer the contrasting winter signal corresponds to minimum insolation values which may be reflected by peak abundances ofgloborotalia inflata obliquity forced variations are reflected primarily in sea surface temperature and not in sea surface productivity these temperature fluctuations correspond with ice volume changes registered in the oxygen isotope record at the north atlantic dsdp site 607 this shows that obliquity forced sea surface temperature variations in the mediterranean are primarily driven by glacial cycles

high resolution seismic reflection profiles for the reconstruction of postglacial transgressive shorelines an example from greece abstract in 1982 we carried out a shallow penetration high resolution seismic profiling study on the shelf of the southern argolid peloponnesos greece to identify and map the shores of the late pleistocene and holocene and to establish their coastal environments portable equipment and a local boat were used the lowest glacial shore occurs at 115 to 118 m within the range of global values the subsequent rise across the distinct old land surface left behind many shore features scaps beaches and beach ridges channels and lagoons now buried under a few meters of post transgressive deposits these features cluster at a small number of depths below present sea level suggesting that the rise of the sea usually too fast to leave an imprint was episodically interrupted by brief stillstands or even temporary reversals of climatic or tectonic origin the clusters can be roughly dated with reference to a global sea level rise curve after 6000 yr b p sparse archaeological data establish a local curve the seismic profiling technique convenient and not costly holds promise for the identification of postglacial shores elsewhere prior to sampling for dating it has wide application for environmental reconstructions of vanished coastal zones as a basis for prehistoric resource assessments these applications are illustrated with examples from this study

glacial holocene salinity changes in the mediterranean sea hydrographic and depositional effects oxygen isotope changes as recorded by pleistocene foraminifera from open ocean sediments are primarily a function of changes in the isotopic composition of the global seawater reservoir caused by ice volume changes with a secondary temperature component1 oxygen isotope records from marginal basins such as the gulf of mexico2 the mediterranean sea3 5 and the red sea6 also exhibit the global signal but are far more complicated owing to the strong overprint of local climate conditions in particular glacial interglacial changes in continental aridity and river runoff produce significant salinity changes in these semi enclosed basins using available oxygen isotope records we estimate that glacial 18 000 yr bp salinities in the eastern and western mediterranean sea were 2 7 and 1 2 higher respectively than at present these elevated glacial salinities played an important part in preconditioning the eastern mediterranean for the eventual accumulation of organic carbon rich sediments sapropels at the end of deglaciation

holocene climatic instability a prominent widespread event 8200 yr ago the most prominent holocene climatic event in greenland ice core proxies with approximately half the amplitude of the younger dryas occurred 8000 to 8400 yr ago this holocene event affected regions well beyond the north atlantic basin as shown by synchronous increases in windblown chemical indicators together with a significant decrease in methane widespread proxy records from the tropics to the north polar regions show a short lived cool dry or windy event of similar age the spatial pattern of terrestrial and marine changes is similar to that of the younger dryas event suggesting a role for north atlantic thermohaline circulation possible forcings identified thus far for this holocene event are small consistent with recent model results indicating high sensitivity and strong linkages in the climatic system

evidence for the evolution of an oxygen minimum layer at the beginning of s 1 sapropel deposition in the eastern mediterranean the sediments of the eastern mediterranean basin contain a series of organic rich sapropels intercalated with organic poor nannofossil oozes until recently the timing of the onset of sapropel formation was not known accurately because of the low resolution achievable by conventional radiocarbon dating compilation of all available 14c ams dates show that the base of s 1 the most recent sapropel was initiated 8800 years b p 14c age corrected by 400 years for reservoir effect under a 500 m water column and moved progressively into deeper water reaching depths of 3500 m at 8200 years b p the linear correlation between the age of s 1 onset and water depth r 0 71 suggests that formation of sapropels moved into deeper water at a rate of 1000 m 200 year a model is suggested in which export production which sank below the well mixed surface layers 500 m was respired consuming dissolved oxygen in the levantine deep water until a threshold value was reached when sapropels began to be preserved in the sediment this resulted in a progressively deepening oxygen minimum zone with time until eventually the entire deep water in the basin was oxygen depleted assuming that the threshold value for sapropel formation was complete anoxia it was calculated that primary productivity in the basin during the deposition of s 1 was a factor of 5 greater than that found at present

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

late quaternary planktonic foraminiferal biostratrigraphy strait of sicily mediterranean sea abstract the development of a detailed planktonic foraminiferal biostratigraphy for the late quaternary latest 180 000 years has allowed the dating and correlation of sediments from the strait of sicily principal component analysis of the assemblages has extracted a climatic history similar to that based upon oxygen isotopic oscillations intercore correlations are supported by tephrochronology and sapropel layer stratigraphy identification of termination ia and ib in several high sedimentation rate cores indicates that the mediterranean sea experienced a two stage warming during the last deglaciation cores collected between water depths of 200 and 600 m contain an erosional hiatus near their tops reflecting an increase in the levantine intermediate water flow sometime since 25 000 years b p and as recently as 7000 years b p during deposition of the youngest sapropel layer a distinct and unusual planktonic foraminiferal succession is associated with sapropel layers this begins in a protosapropel layer immediately beneath a sapropel horizon and continues upwards to the immediately overlying oxidized layer

mediterranean climate and oceanography and the periodic development of anoxic events sapropels mediterranean sapropels are layers with elevated organic carbon concentrations that contrast with surrounding sediments which are organic poor sapropels occur quasi periodically in sedimentary sequences of the last 13 5 million years and exist both in the eastern and western mediterranean sub basins they have been the subject of extensive study based on records from both short conventional and long ocean drilling program sediment cores and from a wide variety of uplifted marine sediment sequences on the basin margins and islands previous syntheses in the 1990s and 2000s have discussed how the formation of sapropels is commonly ascribed to deep sea anoxia enhanced export productivity or a combination of these effects however a wealth of new evidence and insights has emerged during the past 1 2 decades based on traditional and novel proxy data as well as modelling which has revealed intriguing new aspects and nuances to the reconstructed conditions hence it is timely to present a new synthesis of current understanding of the processes behind the formation of sapropels which have over the past decade also become a matter of commercial interest in sub salt hydrocarbon exploration in this review we present a context of modern mediterranean climate and oceanography followed by an integrated assessment of the growing understanding of climatological and ocean circulation changes that were associated with sapropel deposition we find that sapropels predominantly formed during astronomically timed episodes when climatic and oceanographic conditions and ecological responses broadly preconditioned the basin for sapropel deposition there is strong correspondence with times of monsoon intensification fuelling runoff from north africa into the mediterranean sea while preconditioning due to sea level rise and regional precipitation and runoff may have contributed as well within these broad episodes of surface buoyancy gain and resultant decline in deep water ventilation specific deposition under dysoxic anoxic or even euxinic conditions occurred within a clearly dynamic system that was characterised by complex spatial and depth dependent patterns gradients with distinct temporal variability on at least decadal to centennial millennial timescales in the final section we evaluate the implications of different modes of deep water removal from silled basins to investigate why sapropels are more frequently and often more intensely developed in the eastern mediterranean than in the western mediterranean

field based validation of a diagenetic effect on g ruber mg ca paleothermometry core top results from the aegean sea eastern mediterranean recent work across the mediterranean sea has illustrated the salinity and overgrowth effects on planktonic foraminiferal mg ca which potentially confound the use of this as a temperature proxy for paleoceanographic reconstructions to test and verify these effects we present new aegean sea results which reveal mg ca values that were unreasonably high to be explained by temperature or salinity variations alone confirming that foraminiferal mg ca is affected by diagenesis we have specifically targeted globigerinoides ruber w sensu stricto from a series of modern core tops spanning a strong sea surface salinity gradient and a minor sea surface temperature range along a north south aegean sea transect scanning electron microscopy analyses show that g ruber specimens were covered by microscale euhedral crystallites of inorganic precipitates this secondary calcite phase seems to be responsible for the anomalously high mg ca ratios and likely formed near the sediment water interface from caco3 supersaturated interstitial seawater we also have clear evidence of diagenetic alteration in a north south direction along the aegean sea possibly depending on salinity and calcite saturation state gradients these observations illustrate the necessity of alternative techniques e g flow through time resolved analysis or laser ablation inductively coupled plasma mass spectrometry to potentially overcome these diagenetic issues and develop a more reliable and sensitive temperature proxy in similar subtropical settings characterized by high salinity excessive evaporation and restricted circulation

eastern mediterranean palaeoclimates from 26 to 5 ka b p documented by pollen and isotopic analysis of a core in the anoxic bannock basin continuous pollen and isotopic records were established for core ban 84 09 gc retrieved from the anoxic bannock basin in the eastern mediterranean on the basis of two 14c dates they document the palaeoclimate between about 25 7 ka b p and 5 2 ka b p in the northern borderlands of the ionian basin the upper half of the core has been redeposited the isotopic record displays a correlation with pollen percentages that is strong and positive for artemisia sage brush and negative for quercus oak the last glacial maximum and the deglaciation are identified by these combined taxa together with chenopodiaceae the glacial maximum around 18 ka b p which has elsewhere been dated from 20 to 15 ka b p has pollen percentages that are high for artemisia and low for quercus the climate in the pollen source area was arid cold in winter briefly warm in summer and sustained the vegetation of a semi desert the onset of deglaciation after 18 ka b p coincides with that of the decline in artemisia pollen percentage however this decline does not indicate reduced aridity because it is accompanied by a pollen percentage rise of the even more arid herbs chenopodiaceae and ephedra throughout the deglaciation from 18 to 11 ka b p the aridity progressively increases culminating at 11 ka b p this trend is briefly interrupted by a more humid event shown by a peak in artemisia pollen percentage and a smaller peak in oak these two peaks are coeval with the bolling allerod chronozone 13 11 ka b p maximum aridity occurs during the younger dryas chronozone 11 10 ka b p afterwards the oak pollen percentage begins a steady increase and its maximum value is coeval with the lowest isotopic value dated at 8760 170 yr b p this period was one of high moisture warm summers and according to altitude mild to cool winters this climate sustained forests that were mediterranean in the lowlands and warm temperate in the uplands a high pollen concentration is observed during this period and reveals the presence of sapropel s1 which is otherwise unrecognizable in this entirely black core during the following period between 8760 170 and 5200 yr b p the 180 reverts to slightly higher values and the quercus pollen percentage decreases while the pollen percentage of the wetter ostrya the oriental hornbeam increases the high pollen concentration during the deposition of sapropel s1 cannot have been caused by increased pollen input into the sea this pollen being wind borne nor by increased pollen production for all taxa both trees and herbs we conclude that it is entirely due to increased preservation of this allochtonous organic material by the deep anoxia of the bottom water below a thick anoxic water column the coincidence of sapropel deposition with warm and humid local climate as well as with the second global meltwater pulse suggests that the cessation of bottom water ventilation was due to decreased surface water density resulting from less saline incoming atlantic surface water increased local runoff and warmer winters

limestone caves and the quaternary record of terrestrial tetrapods on islands the potential for finding quaternary tetrapod fossils on islands is governed by a combination of biodiversity geology fossil preservation and time span of records islands with extensive limestone exposures are particularly well represented at low and middle latitudes where biodiversity is potentially high and the caves and karst fissures in these landscapes have proven to be rich reliquaries of the quaternary fossil record this is particularly apparent when we contrast limestone islands with volcanic islands in the lesser antilles the latter present a serious deficiency in the fossil vertebrate record and an impediment to understanding the biogeography of the region caves and karst fissures are also ephemeral on geological time scales and few tropical island sites are known that are older than the last interglacial in britain important cave sites of middle pleistocene age are known but are rare

paleoenvironmental changes since 3000 bc in the coastal marsh of vravron attica se greece abstract the coastal area of the vravron bay in the vicinity of the homonym archaeological site is a marshy plain located on the eastern part of the attica peninsula eastern greece in order to provide evidence for palaeoenvironmental changes and landscape evolution of the area detailed micropaleontological palynological and sedimentological analyses have been conducted at the underlying late holocene coastal deposits the recovered sediments lithostratigraphic units a d represent a continuous record of the environmental history of the area since the early bronze age covering all subsequent historical periods the base of the recovered deposits is older than the 3rd millennium bc until late medieval times the studied sequence contains plenty evidence for the existence of the natural port reported from the mycenaean lithostratigraphic unit a that infilled after repeated flooding events during the classic period lithostratigraphic unit b and gradually developed into a shallower marine environment lithostratigraphic unit c in the uppermost part of the sequence lithostratigraphic unit d a transition towards brackish environment with intense fresh water input is featured around 1540 ad signs of human agricultural activities in vravron appear since 3000 bc early bronze age and are linked to the history of inhabitation in the area

climatic changes in the northern red sea during the last 22 000 years as recorded by calcareous nannofossils 1 we present a high resolution record of calcareous nannofossils from the northern red sea for the last 22 kyr extreme conditions with enhanced salinities during the last glacial maximum are characterized by high values of gephyrocapsa ericsonii the dominance of emiliania huxleyi in heinrich event 1 indicates a climatic cooling favoring the bloom of opportunistic species the calcareous nannofossils record a two step onset of the postglacial humid climate punctuated by the younger dryas both steps show an early oligotrophic phase dominated by florisphaera profunda and gladiolithus flabellatus and a subsequent fertile phase characterized by e huxleyi the younger dryas is described by high values of gephyrocapsa oceanica indicating an increased mixing of the water column in the late holocene repetitive increases in abundance of f profunda and g flabellatus reflect restricted oligotrophic conditions caused by the high aridity following the holocene humid period

reconstructing the seafloor environment during sapropel formation using benthic foraminiferal trace metals stable isotopes and sediment composition the evolution of productivity redox conditions temperature and ventilation during the deposition of an aegean sapropel s1 is independently constrained using bulk sediment composition and high resolution single specimen benthic foraminiferal trace metal and stable isotope data the occurrence of benthic foraminifer hoeglundina elegans h elegans through a shallow water 260 m sapropel permits for the first time a comparison between dissolved and particulate concentrations of ba and mn and the construction of a mg ca based temperature record through sapropel s1 the simultaneous increase in sedimentary ba and incorporated ba in foraminiferal test carbonate ba ca h elegans points to a close coupling between ba cycling and export productivity during sapropel deposition sedimentary mn content mn al sed is reduced corresponding to enhanced mn2 mobilization from sedimentary mn oxides under suboxic conditions the consequently elevated dissolved mn2 concentrations are reflected in enhanced mn ca h elegans levels the magnitude and duration of the sapropel interruption and other short term cooling events are constrained using mg ca thermometry based on integrating productivity and ventilation records with the temperature record we propose a two mode hysteresis model for sapropel formation

coccolithophore assemblages during the holocene climatic optimum in the ne mediterranean aegean and northern levantine seas greece paleoceanographic and paleoclimatic implications recent paleoceanographic findings suggest that during the holocene ne mediterranean climate was less stable than previously thought several recently generated aegean paleoceanographic records of sapropel s1 suggest that during the holocene short term potentially global cooling episodes reflecting the n atlantic climatic fluctuations and possibly related to solar variability are superimposed on the underlying regional subtropical tropical control on the hydrography and ecosystems detailed quantitative analyses of coccolithophores have been performed on the deep sea deposits of the ne mediterranean sea four gravity core records from north aegean sea sl 152 se aegean ns 14 ns 18 and south cretan continental margin northern levantine sea hcmr 2 22 respectively with a focus on the regional expression of sapropel s1 deposition in all sites higher values of florisphaera profunda helicosphaera carteri braarudosphaera bigelowii and the increase of stratification s index within sapropel intervals can be interpreted as the result of elevated marine production in the deep photic zone and enhanced inflow of fresh water input during the s1 period the stratification s index is significantly higher in the north aegean in respect to se aegean and the south cretan margin scm reflecting increased coccolithophore productivity at the lower photic zone being associated with a remarkably stratified water column the concomitant increased presence of b bigelowii indicates the prominent riverine input in the north aegean basins and possible influx of black sea waters after 9 0 ka bp consequently the increased stratification of the water column is linked to the significant freshening of the north aegean surface waters particularly during the early stages of the holocene climatic optimum s1a depositional interval a series of cooling events detected towards the end of sapropelic conditions 7 2 ka bp mostly in the north aegean site may be linked to outbursts of cold northerly air masses and relevant pulses in the deep intermediate water ventilation that caused the enhancement of surface marine productivity and the temporary cessation of s1 at 8 0 ka bp in contrast in the se aegean and the northern levantine sea the water column remains still warm and stratified influenced by moderate fresh water input for at least 1 more ky

circulation changes and nutrient concentrations in the late quaternary aegean sea a nonsteady state concept for sapropel formation sapropel forming conditions we identify the start of seasonal stratification and highlight a lag in d 18 o response of the planktonic foraminifer n pachyderma to termination t1b as identified in the d 18 o record of g ruber by use of a simple model we determine that this offset cannot be a function of bioturbation effects the lag is of the order of 1 kyr and suggests that isolation of intermediate deep water preceded the start of sapropel formation by up to 1 5 kyr using this discovery we propose an explanation for the major unresolved problem in sapropel studies namely the source of nutrient supply required for export productivity to reach levels needed for sustained sapropel deposition we suggest that nutrients had been accumulating in astagnant basin for 1 1 5 kyr and that these accumulated resources wereutilized duringthe deposition of s1 in addition we provide a first quantitative estimate of the diffusive 1 e mixing timescale for the eastern mediterranean in its stratified sapropel mode which is of the order of 450 years index terms 1050 geochemistry marine geochemistry 4835 4850 3030 marine geology and geophysics micropaleontology 3339 meteorology and atmospheric dynamics ocean atmosphere interactions 0312 4504 4267 oceanography general paleoceanography 4870 oceanography biological and chemical stable isotopes keywords sapropel mediterranean holocene foraminifera climate variability

atlantic mediterranean water exchange during the late neocene the nature of water exchange between the mediterranean and the atlantic is examined for three time periods during the late neogene in order to assess the impact of flow patterns between these basins on bottom water conditions in the oceans the large volume of carbonates and evaporites deposited in the mediterranean during the messinian salinity crisis appears to have caused the open ocean to become more undersaturated in calcium carbonate resulting in increased dissolution of deep sea carbonates during the latest miocene during the earliest pliocene an estuarine type of flow existed between the atlantic and mediterranean waters entered the mediterranean at depth and flowed out at the surface benthic foraminiferal stable isotopic evidence from the north atlantic indicates that north atlantic deep water nadw was produced throughout the early pliocene and that the absence of saline mediterranean outflow did not have a significant effect on bottom water production eustatic lowering of sea level during the last glacial maximum 18 000 years b p reduced water exchange between the atlantic and the mediterranean as a result salinities in the mediterranean increased substantially but it seems unlikely that diminished nadw production during the last glacial episode can be attributed to a reduction in mediterranean outflow

vertical distribution and isotopic fractionation of living planktonic foraminifera from the panama basin a model1 2 which explains the vertical and seasonal distribution of planktonic foraminifera was developed using data from the western north atlantic and is comprised of three tenets 1 the conditions in the photic zone upper 80 100 m exclusively dictate planktonic foraminifera species composition and abundance throughout the water column 2 species are vertically stratified within the photic zone according to their temperature preference depth distribution according to temperature preference has been proposed by several authors3 based on isotope analyses of sediments due to seasonal temperature variations seasonal variations in the 18o composition of seawater and species specific isotope fractionation rigorous proof of this hypothesis cannot be provided from sediment analyses alone 3 the chlorophyll maximum is a major food source zone which is preferentially exploited by foraminifera our data from the panama basin which are presented here are confirmation of this model the panama basin in the eastern equatorial pacific which has a shallow and steep thermocline was sampled for living planktonic foraminifera a multiple opening closing net and environmental sensing system mocness 4 was used to collect 13 sets of eight vertically stratified oblique samples we report here the quantitative distribution and stable isotopic composition of planktonic foraminifera from four mocness tows taken over 5 days during august 1979 rv knorr cruise 73 at 5 20 n 8 50 w each tow consisted of eight samples which integrated 12 5 m intervals from 0 to 100 m for moc 126 25 m intervals from 0 to 200 m for moc 127 100 150 m intervals from 0 to 1 000 m on moc 128 and 250 m intervals from 0 to 2 000 m on moc 131

a multiproxy approach of the holocene evolution of shelf slope circulation on the nw iberian continental shelf abstract textural mineralogical geochemical and microfaunal data benthic foraminifera were studied along the omex core ksgx 40 recovered in the galicia mud deposit of the nw iberian outer continental shelf off the ria de vigo north of spain this core included the records of the last ca 4 8 ka cal bp and consists from the base to the top of a sedimentary sequence exhibiting gradual upward decrease in grain size sediments of this core are mainly siliciclastic largely composed of quartz k feldspars plagioclases and phyllosilicates mica illite kaolinite and chlorite showing a great continental influence in this zone two periods of deposition of finer sediments are registered between 2 2 1 2 ka cal bp and 0 5 0 ka cal bp since the last 2 2 ka bp but mainly during both muddy intervals the galicia mud deposit was nourished with a lower and finer supply of detrital minerals compensated by higher amounts of organic matter as it is suggested by a benthic foraminifera high productivity bfhp proxy processes involved in organic matter degradation by aerobic organisms led to depressed levels of oxygen in the sediments as shown by a benthic foraminiferal oxygen index bfoi peaks of redox sensitive elements like mn fe cu ni cr co zn ni and pb as well as the presence of diagenetic minerals such as pyrite suggest the development of anoxic conditions beneath the sedimentary surface and early diagenetic changes due to high organic matter flux in both muddy intervals two different hydrodynamic regimes were inferred through the analysis of the different proxies textural mineralogical geochemical and benthic foraminifera 1 a strong hydrodynamic regime between 4 8 and 2 2 ka cal bp characterized by the prevalence of winter storms which gave rise to a deep mixed layer on the shelf 2 weak hydrodynamic regime between 2 2 1 2 ka cal bp and 0 5 0 ka cal bp with a high predominance of upwelling and an increase in oceanic stratification

variation of deepwater convection in the western mediterranean sea gulf of lion during the last 28 ka abstract the oxygen and carbon isotopes record from fossil foraminifera in deep sea sediments are commonly used as proxy for global thermohaline and productivity changes the last 28 ka record of oxygen and carbon isotopes are characterized by a slow transfer of isotopic signal from surface to deep mediterranean at the beginning of heinrich events h2 and h1 and during the bolling allerod these changes in deep waters properties occur some 180 years later indicating a decrease of ventilation in the beginning of these events the slowing of the thermohaline convection is more marked in the early holocene characterized by less than 500 years of lag time between the isotopic signals

chronology of quaternary shoreline progradational sequences related to eustatic sea level changes sedimentation and subsidence in saronikos gulf greece abstract the stacking pattern of shoreline progradational sequences in subsiding basins have been used as a chronologic tool in the mediterranean region most previous studies have used a few key seismic lines seaward of deltas where the record is complicated by deltaic distributary switching southeastern saronikos gulf in the western aegean sea at the northwestern end of the south aegean arc lacks large river input of sediment the ene wsw and nw se trending neotectonic aegina and methana basins lie between the tectonically active gulf of corinth and the relatively stable cyclades plateau new high resolution seismic profiles from southeastern saronikos gulf have been interpreted according to the principles of seismic and sequence stratigraphy alpine basement and marine pliocene sediments have been recognized in the surrounding basin margins and more than 300 m and 150 m of unconsolidated sediments have been mapped in aegina and methana basin respectively progradational clinoforms that toplap against transgressive surfaces have been traced along strike leading to the establishment of a robust chronostratigraphic framework further controlled by sedimentation rates as extracted from cores southeastern saronikos gulf poses an outstanding example of development of progradational wedges formed within a microtidal wave dominated regime of low sedimentation rates between 2 8 cm ka and 3 2 cm ka within the framework of low subsiding basins with rates between 0 03 and 0 31 m ka in this environment more than 180 well preserved shoreline progradational units with attributes similar to the ones reported from the aegean and eastern mediterranean seas have been mapped and correlated to sea level lowstands back to 866 ka deeper mid pleistocene progradational units are also recognized tentatively back to 1 4 ma subsidence rate shows a dramatic decrease in the last 1 ma and significant numbers of faults became inactive during the last 130 ka in early middle quaternary methana basin was an isolated lake and extended terrestrial areas were shaped in the poros agios georgios plateau during sea level lowstands aegina basin was continuously connected to the aegean through the agios georgios fault valley this study demonstrates the robustness of chronology based on stacked shoreline progradational sequences and its applicability to determining rates of tectonic subsidence

a novel mineralogical approach for provenance analysis of late quaternary marine sediments the case of myrtoon basin and cretan sea aegean greece abstract sediments from two deep sea bottom cores from the myrtoon basin in the sw aegean sea and eastern cretan sea were examined by quantitative mineralogical and geochemical analysis to infer sediment provenance and climatic conditions and palaeo environmental control on sediment deposition both cores contain calcareous muds and silts with dark olive grey organic rich intervals corresponding to the regional sapropel s1 horizon the presence of a few tephra layers documents volcanic activity in the southern part of the aegean sea the bulk sediments contain abundant carbonate minerals mainly calcite and mg calcite and clay minerals mainly illite and smectite and accessory serpentine talc and hornblende which attest to contributions from ultrabasic sources there is a sharp decrease of the mg calcite content and the mg ca ratio of the carbonate fraction in sapropelic sediments followed by an increase of the average grain size a well expressed negative relationship between illite and smectite was observed in the clay fraction in full accordance with previous studies however this trend is absent from the bulk sediments because smectite is significantly overestimated in the oriented clay fractions clay mineral distribution is controlled mainly by sediment sorting with deposition in the sapropelic sediments being also affected by climatic changes the different types of smectite in the cores and the presence of smectite with high dehydroxylation temperature in the se aegean suggests that the sediment supply from se mediterranean sources should be limited

late quaternary changes in mediterranean intermediate water density and formation rate three recently acquired eastern mediterranean cores containing late quaternary sediments display a marked faunal contrast between the holocene and older sapropels it is suggested that the absence of neogloboquadrinids in the holocene sapropel and their abundance in older sapropels reflect differences in food availability related to the extent of development of a deep chlorophyll maximum layer dcm and the intensity of new primary production associated with this layer the depth of such a layer which consists of phytoplankton with a characteristic taxonomic composition is determined by the vertical hydrodynamical structure during deposition of the older sapropels the pycnocline was apparently positioned well above the base of the euphotic layer a situation that favors a pronounced dcm and an associated relatively high rate of new production shallowing of the pycnocline implies a relatively low density of the mediterranean intermediate water miw on the other hand during deposition of the holocene sapropel the pycnocline had apparently vanished due to termination of miw formation

deep sea benthic foraminifera record of the last 1500 years in the north aegean trough northeastern mediterranean a paleoclimatic reconstruction scenario abstract a 1500 year high resolution deep sea benthic foraminifera record from the athos basin of the north aegean trough northeastern mediterranean has been analyzed for the development of a paleoclimatic scenario the data analysis points out that the quantity and quality of the seafloor s organic matter could be a crucial controlling factor for the faunal succession during 550 1000 ad within the medieval climate anomaly the relatively high benthic foraminiferal accumulation rates together with the predominance of meso eutrophic taxa such as bolivina dilatata spathulata may be interpreted as the result of high precipitation consequently increased riverine discharges into the north aegean sea and the associated warm climatic conditions appear to persist for a long time and are related to a negative phase of the north atlantic oscillation later on the establishment of an oligo mesotrophic seafloor environment is documented by the diminishing benthic foraminiferal accumulation rates associated with an increment in the abundances of gyroidinoides altiformis during a colder phase of the little ice age 17th century the relative abundances of the opportunistic foraminiferal species bulimina inflata and bulimina marginata can be related to high marine productivity most probably due to enhanced winter mixing conditions finally during the last 100 years a faunal shift to eutrophication preferent species and the persistent occurrence of chilostomella mediterranensis reflects a pronounced change in trophic conditions characterized by high amounts of potentially low quality organic matter in the seafloor which are the result of a gradual temperature increase accompanied with enhanced terrigenous inputs

after the deluge mediterranean stagnation and sapropel formation in an east mediterranean marine core the upper sapropel begins soon after the start of a global event a very heavy precipitation which occurred in the equatorial latitudes during the late glacial early holocene this heavy precipitation in africa channelled by the nile river across 35 of latitude produced a low salinity surface layer in the east mediterranean in this confined basin with high bottom salinity the steep salinity gradient stratified the water column the stagnant bottom waters triggered the sapropel formation cretaceous sapropels in the tropical oceans may result from the same chain of events in warm humid climates with contrasting wet and dry seasonal rhythm

living stained deep sea foraminifera from the sea of marmara a preliminary study abstract in this preliminary study we investigate living stained foraminifera from the sea of marmara we focus on the faunal composition and geochemical signatures trace elements carbon and oxygen stable isotopes in foraminiferal tests at two deep sea sites 329 and 1240 m depth respectively documented by rov observations and sampling both study areas are heterogeneous including bacterial mats and carbonate concretions proximal to cold seeps and consist of dysoxic bottom water o2

the impact of rapid early to mid holocene palaeoenvironmental changes on neolithic settlement at nea nikomideia thessaloniki plain greece the site of nea nikomideia is one of the oldest and most important neolithic settlements in northern greece and the wider balkan peninsula having been first occupied by early farmers at around 6500 cal bc important archaeological excavations conducted in the 1960s suggested that the settlement was located close to an ancient coastline during the neolithic however palaeoenvironmental change and landscape evolution in the vicinity of the site have seldom been considered in detail six cores from the western and central parts of the thessaloniki plain were therefore drilled in 2008 and subjected to palaeoenvironmental analyses including sedimentology laser grain size and magnetic susceptibility measurements chemical analysis loss on ignition and carbonate content stable isotopes analysis coupled with x ray diffraction measurements molluscan faunal analysis and radiocarbon dating the recognition of several important facies representing freshwater lacustrine and fluvial and brackish lagoonal and marine influenced conditions have shed light on the environmental and landscape evolution of the western part of the thessaloniki plain and associated impacts on human occupation during the last 10 000 years the general sequence proved in the cores indicates the predominance of lacustrine conditions during the early holocene with the occurrence of a marine transgression at c 6000 5800 cal b c this major palaeoenvironmental change corresponds with the 8 2 ka event and is a likely cause for the desertion of nea nikomideia at that time subsequent regression of the shoreline to the east saw that the area around nea nikomideia returns to predominantly terrestrial conditions and the deposition of lacustrine and fluvial deposits

seasonal salinity changes during mediterranean sapropel deposition 9000 years b p evidence from isotopic analyses of individual planktonic foraminifera using stable isotopic analyses of individual tests of planktonic foraminifera with different seasonal and depth habitats we have investigated temporal variations in surface water salinities in the eastern mediterranean during the past 13 000 years low oxygen isotopic values document the presence of anomalously low salinity conditions in the eastern mediterranean at about 13 000 years b p 4000 years before the deposition of the youngest sapropel by 11 000 years b p during the deposition of presapropel sediments low salinity surface waters were more pervasive but were restricted to summer months and only affected the surface of the water column at the onset of sapropel deposition about 9000 years b p surface salinities in the eastern mediterranean had decreased by almost 4 and had extended to depths of at least 75 m the low salinity surface lens was not however a permanent feature of the eastern mediterranean during sapropel deposition low salinity surface conditions occurred in the fall and winter seasons but normal sea surface salinities returned during spring months on a seasonal and or interannual basis thus a low salinity surface lens could have existed continuously for months or decades at a time but would have been interrupted intermittently by a return to normal conditions any triggering mechanism proposed for mediterranean sapropels must account for the seasonal fluctuations and ephemeral nature of low salinity conditions in the eastern mediterranean despite normal salinities returning occasionally during spring months a low salinity surface lens may have greatly inhibited the production of levantine intermediate water prevented the formation of adriatic deep water and consequently reduced ventilation of the eastern mediterranean

late quaternary central mediterranean biochronology jorissen f j asioli a borsetti a m capotondi l de visser j p hilgen f j rohling e j van der borg k vergnaud grazzini c and zachariasse w j 1993 late quaternary central mediterranean biochronology mar micropaleontol 21 169 189 a high resolution biochronology is presented for the late quaternary of the central mediterranean in the late pleistocene holocene successions three assemblage zones are distinguished on the basis of frequency patterns of planktic foraminifera the age of these zones is determined by accelerator mass spectrometry ams t4c dating the zonal boundaries are dated at 12 700 yr b p the end of termination la and 9600 yr b p the start of termination ib respectively the ams dates show that major changes in the planktic and benthic realms occurred synchronously over wide areas although records of individual species may show important regional differences in the studied areas resedimentation processes revealed by anomalous successions of 14c dates play a far more important role than indicated by the sedimentological and micropaleontological data possibly these processes contribute to the very high accumulation rates in the glacial zone ill although the ams technique has increased the accuracy of lac measurements of older carbonate may still lead to substantial age differences between areas with different sedimentary regimes

organic geochemical evidence of late glacial holocene climate instability in the north aegean sea sedimentary molecular biomarker compositions organic carbon and caco3 concentrations and bulk organic 13c and total 15n values document a series of paleoclimatic changes that have affected organic matter production and sedimentation in the north aegean sea from the termination of the latest glacial maximum through the middle holocene continental environmental conditions have been inferred from land plant biomarkers paleoproductivity patterns of diatoms prymnesiophytes dinoflagellates and nannoplankton were discerned from marine derived biomarkers although organic matter is predominantly marine variations in the proportion of marine and land contributions and in its general preservation are evident rapid changes in the eastern mediterranean thermohaline circulation evidently occurred in parallel to sea surface temperature oscillations enhanced deep water ventilation accompanied cold intervals in the late last glacial the younger dryas and during an interruption of deposition of the s1 sapropel probably in response to strengthening of north winds over the region in contrast decreased thermohaline circulation occurred during the warm interval associated with the s1 sapropel during this period increased freshwater inputs diminished ventilation of deep water masses and enhanced organic matter production and preservation intriguing fluctuations in sea surface temperatures and the concentrations of marine and terrestrial biomarkers within the sapropelic layer most prominently in the interruption from 8 2 to 7 8 calibrated radiocarbon conventional kyr bp support the hypothesis that several distinct events of deep water reoxygenation occurred in the north aegean sea during deposition of the s1 sapropel these events reflect centennial excursions to the more common low productivity and well ventilated conditions of the mediterranean that may possibly be related to north atlantic oscillation cycles

vegetation dynamics and climate during the deglaciation in the south adriatic basin from a marine record the pollen record of a marine core in the south adriatic basin that is radiometrically dated and correlated to the global climate variation by the oxygen isotope curve documents the vegetation changes which occurred around that basin since 17 ka thousands year bp during the end of the last glacial maximum at 16 7 15 ka the altitudinal range is occupied at low and high elevations by a desert and a semi desert dominated by the shrubby sage brush artemisia and at middle elevation by a grass steppe with stands of pine trees where soil conditions are favourable during the deglaciation between 15 and 10 ka a steppe forest with a succession of deciduous trees appears at middle elevation within the grass steppe but its development is interrupted by a set back a re expansion of the semi desert which is coeval with the younger dryas of higher european latitude the holocene is identified by the spread of the mixed deciduous and mediterranean forests which culminates between 8 6 and 6 ka during the end of the boreal and the atlantic chronozones while the most recent sapropel is formed in the deep marine basins of the eastern mediterranean including the south adriatic one between the cold and arid glacial maximum and the warmest and wettest climate optimum during the atlantic chronozone this vegetation dynamics is constrained by the availability of moisture at low elevation by temperature at high elevation and by a combination of both at middle elevation

benthic foraminiferal successions across late quaternary mediterranean sapropels abstract benthic foraminiferal records across late quaternary mediterranean sapropels s6 s5 and s1 are reviewed and re considered in the light of recent advances in foraminiferal ecology it is suggested that the main factor controlling the foraminiferal successions that occur immediately before and after sapropel deposition is the amount of time involved in the onset of anoxic conditions and in the re oxygenation of the benthic environment faunas dominated by deep infaunal taxa such as globobulimina and chilostomella reflect a very gradual decrease or increase of bottom water oxygenation post sapropel faunas dominated by small biconvex trochospiral taxa which are inferred to have a much more opportunistic life strategy are typical of a very rapid re oxygenation of the benthic environment after sapropel deposition the time involved in re oxygenation depends upon the mechanism causing sapropel formation the faunal succession found above sapropel s5 suggests a basin with a strong density gradient in the upper part of the water column during sapropel deposition followed by a rapid turnover of the following column and quick re oxygenation of the benthic environment in contrast the faunal succession above sapropel s6 suggests a water column with a more gradual density gradient deeper in the basin a progressive deepening of the halocline and a very slow increase of bottom water oxygenation

the formation of eastern mediterranean sapropels abstract sapropel formation in the eastern mediterranean is explained by an oceanographic approach it is suggested that sapropels are not only a consequence of eustatic sea level changes as earlier proposed by olausson a model which is widely accepted but rather a result of a very sensitive reaction of the eastern mediterranean to any small climatic amelioration present day aeration of the deep eastern mediterranean basin results from circulation of oxygen rich deep water originating mainly in the adriatic assuming present day conditions a climatic amelioration towards more humid and warmer conditions leading to an increase of the water temperature in the adriatic basin by 0 7 c or to a decrease of its salinity by only 0 2 will cause stratification of water masses and enhance sapropel formation

late glacial holocene climate variability at the south eastern margin of the aegean sea abstract new micropaleontological palynological and geochemical results from a relatively shallow 500 m sediment core ns 14 in the south eastern aegean sea provide a detailed picture of the regional expression of sapropel s1 formation in this sub basin of the eastern mediterranean sea specifically freshwater input during 10 6 10 0 ka bp has preceded the deposition of s1 further decrease in surface water salinity is evidenced between 10 0 and 8 5 ka bp at the lower part of s1a which in respect to s1b is featured by warmer 19 5 c and more productive surface waters associated with dysoxic bottom conditions a series of coolings detected within the s1 depositional interval may be linked to outbursts of cold northerly air masses and relevant pulses in the deep intermediate water ventilation that caused the s1 interruption between 7 9 and 7 3 ka bp and culminated during the deposition of s1b with the decline of deep chlorophyll maximum dcm at 6 5 ka bp the climate instability and the relevant absence of anoxia weakened the organic matter preservation in the shallow south eastern aegean margin during the s1 times ns 14 record provides evidence for a distinct mid holocene warm up to 25 c and wet phase associated with the deposition of the sapropel like layer smh sapropel mid holocene between 5 4 and 4 3 ka bp the smh layer could represent evidence of on going albeit weak african monsoon forcing only expressed at the south eastern edge of the aegean sea its end is associated with the 4 2 ka bp northern hemisphere mega drought event and the termination of the african humid period at 3 8 ka bp

organic carbon distribution and isotopic composition in three records from the eastern mediterranean sea during the holocene we investigated the distribution of organic carbon toc and bulk organic 13 c org values in two cores from the aegean sea and one from the libyan sea eastern mediterranean sea ems with a focus on the timing and regional expression of sapropel s 1 deposition in the early holocene our data indicate that the onset of s 1 occurred earlier in the libyan sea 9 8 kyr bp than in the aegean sea 8 9 kyr bp implying that dysoxia anoxia started earlier in the deeper sites of the ems than in the shallower sites in the aegean sea accumulation rates of organic matter om during the s 1 period have a clear decreasing gradient from north to south with higher values in the aegean sea and toc contents higher in the deep basin the three sedimentary sequences exhibit 13 c org values that fall within the range of algal om 25 to 20 shifts to lighter 13 c org values within sapropel intervals in the aegean sites can be interpreted as the result of elevated marine production enhanced inflow of light terrestrial dissolved inorganic carbon and or of the shoaling of the pycnocline along with the presence of a deep chlorophyll maximum dcm during the s 1 period

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

deep sea ecosystem variability of the aegean sea during the past 22 kyr as revealed by benthic foraminifera abstract specific responses of the regional deep sea ecosystems to climatic and oceanographic processes during the last 22 kyr are revealed by benthic foraminiferal faunas from two cores in the northern and southern aegean sea under glacial boundary conditions high diversity benthic foraminiferal faunas and elevated benthic foraminiferal numbers indicate enhanced organic matter availability and well ventilated deep water masses in the whole aegean sea the glacial termination is accompanied by significant fluctuations in productivity and deep water ventilation in the northern aegean sea meltwater inflow from mountain glaciers during the bolling allerod warm period resulted in a restriction of local deep water formation as mirrored by a dominance of bolivinids during the deposition of sapropel s1 drops in benthic foraminiferal number and diversity are more significant in the southern aegean sea when compared to the north this suggests the persistence of local deep water formation in the northern aegean sea during s1 deposition in addition faunal fluctuations within s1 at both sites suggest the repeated influence of short term cooling events on the re ventilation and re colonization of aegean deep sea ecosystems during the middle and late holocene benthic foraminiferal faunas document the establishment of oligotrophic and well ventilated conditions in the southern aegean sea the corresponding faunas from the northern aegean sea reflect generally mesotrophic conditions and variable deep water oxygenation during the entire holocene the deep sea ecosystems of this region responded very sensitively to short term changes in humidity and temperature these abrupt climate changes controlled the inflow of nutrients from rivers and the black sea and the formation of local deep water masses

water column dynamics during the last interglacial anoxic event in the mediterranean sapropel s5 1 marine organic rich sediments are important for long term carbon sequestration and as a source of fossil hydrocarbons but the processes underlying their formation remain elusive we present a multiproxy analysis of a relatively recent well preserved mediterranean organic rich deposit known as sapropel s5 which formed 124 119 thousand years ago ka b p where b p references year 1950 combining planktonic foraminiferal abundance records with stable isotope and organic biomarker data we reconcile the apparently contradicting coexistence of deep dwelling foraminiferal faunas with green sulphur bacteria that indicate photic zone euxinia s5 started with a rapid freshwater induced increase of density stratification that inhibited vertical mixing and deepwater ventilation through the first 900 years anoxic to euxinic deepwater conditions developed and extended up to roughly 200 m water depth then followed a 4100 year period of variability in the depth intensity of winter mixing with a roughly 1400 year periodicity coincident with fluctuations in water column stability s5 terminated with a marked decrease in density stratification and consequently renewed convective overturn

late quaternary paleoceanography as recorded by benthonic foraminifera in strait of sicily sediment sequences at specific times during the late quaternary a widespread low salinity surface water layer was produced over the eastern mediterranean which created stagnant conditions and associated deposition of sapropelic muds in the deep basins the strait of sicily has been positioned above the anoxic deeper water masses and is therefore devoid of sapropel deposits sediment sequences in the region contain a valuable record of upper bathyal 200 1000 m benthonic foraminiferal change during times of deep basin stagnation quantitative examiniation of benthonic foraminiferal assemblages in strait of sicily quaternary cores generally reveals changes coeval with sapropels s1 s2 s4 s5 and s6 the benthonic foraminiferal expression is seen as increases in frequency ofglobobulimina affinis globobulimina pseudospinescens chilostomella mediterranensis bolivina dilatata and otherbolivina species during intervals corresponding to the episodic abyssal stagnation events some cores also display a decrease incassidulina carinata and an increase inarticulina tubulosa similar assemblage changes have been previously documented to be closely associated with the sapropel layers in the deep basins of the eastern mediterranean the actual sapropel layers usually do not contain benthonic foraminifera however in the strait of sicily area the species exhibit less drastic changes than in the deep eastern basins because of the less severe anoxic conditions in the deep eastern basins benthonic foraminifera almost totally disappeared in sapropel layers at the same time there was a general reduction in foraminiferal numbers in the shallower strait area

short term climate changes in the southern aegean sea over the last 48 000 years abstract high resolution palaeoenvironmental changes corresponding to a mean time interval of 450 years covering the last 48 000 years were examined in a core from the cretan basin in the southern aegean sea the intensity and duration of the climatic and oceanographic events were determined by examining the compositional changes in the planktonic foraminifera and pollen assemblages along with the 18o signal of globigerinoides ruber a reconstruction of sea surface temperatures was attempted using the modern analogue technique mat in total 10 stadials and 6 interstadials occurred over the last 48 000 years these fluctuations in climatic conditions coincide with fluctuations documented in the western and central mediterranean and seem to be associated with dansgaard oeschger events some of these climatic fluctuations are correlated with changes in the vegetation in the surrounding land between 48 and 10 cal kyr bp the most pronounced stadials occurred at 41 cal kyr bp c69 st10 and at 13 cal kyr bp c69 st4 these events are characterized by i high positive 18o values of globigerinoides ruber ii drops in sst and iii increases in aridity these events may be correlated with the heinrich h4 event and the younger dryas event respectively two other stadials at 23 cal kyr bp c69 st6 and at 16 cal kyr bp c69 st5 which are characterized by increases in the abundance of the cold plaktonic foraminifera species and increases in aridity may be correlated with the h2 and h1 events respectively the dominant planktonic foraminiferal species during the stadials witch are correlated with the heinrich events were turborotalita quinqueloba and globorotalia scitula the most pronounced interstadials occurred between 39 5 and 38 5 cal kyr bp c69 ist6 and between 25 and 24 cal kyr bp c69 ist3 and are characterized by depletion in 18o values increases in sst and increases in humidity the former event coincides with the formation of the sapropelitic layer s2 in the holocene the most pronounced stadial occurred between 8 and 6 5 cal kyr bp c69 st2 during the interruption of s1 and is characterized by a reduction in sst and an increase in aridity the most pronounced interstadials of holocene occurred during the formation of s1a and s1b between 9 and 8 cal kyr bp c69 ist1 and between 6 5 and 5 5 cal kyr bp c69 ist2 respectively these events are characterized by depletion in 18o values increased sst and an increase in humidity as is indicated by the expansion of temperate evergreen and mediterranean taxa in the pollen record

the temperature of europe during the holocene reconstructed from pollen data we present the first area average time series reconstructions of warmest month coldest month and mean annual surface air temperatures across europe during the last 12 000 years these series are based on quantitative pollen climate reconstructions from over 500 pollen sites assimilated using an innovative four dimensional gridding procedure this approach combines three dimensional spatial gridding with a fourth dimension represented by time allowing data from irregular time series to be focussed onto a regular time step we provide six regional reconstructed temperature time series as well as summary time series for the whole of europe the results suggest major spatial and seasonal differences in holocene temperature trends within a remarkably balanced regional and annual energy budget the traditional mid holocene thermal maximum is observed only over northern europe and principally during the summer this warming was balanced by a mid holocene cooling over southern europe whilst central europe occupied an intermediary position changes in annual mean temperatures for europe as a whole suggest an almost linear increase in thermal budget up to 7800 bp followed by stable conditions for the remainder of the holocene this early holocene warming and later equilibrium has been mainly modulated by increasing winter temperatures in the west which have continued to rise at a progressively decreasing rate up to the present day

evidence for massive discharges of icebergs into the north atlantic ocean during the last glacial period sediments in the north atlantic ocean contain a series of layers that are rich in ice rafted debris and unusually poor in foraminifera1 here we present evidence that the most recent six of these heinrich layers deposited between 14 000 and 70 000 years ago record marked decreases in sea surface temperature and salinity decreases in the flux of planktonic foraminifera to the sediments and short lived massive discharges of icebergs originating in eastern canada the path of the icebergs clearly marked by the presence of ice rafted detrital carbonate can be traced for more than 3 000 km a remarkable distance attesting to extreme cooling of surface waters and enormous amounts of drifting ice the cause of these extreme events is puzzling they may reflect repeated rapid advances of the laurentide ice sheet perhaps associated with reductions in air temperatures yet temperature records from greenland ice cores appear to exhibit only a weak corresponding signal moreover the 5 10 000 yr intervals between the events are inconsistent with milankovitch orbital periodicities raising the question of what the ultimate cause of the postulated cooling may have been

sea land correlation of pollen records in the eastern mediterranean for the glacial interglacial transition biostratigraphy versus radiometric time scale abstract pollen diagrams based on marine cores from the eastern mediterranean and arabian seas and land cores from greece turkey the levant and western iran during the last deglaciation reveal a similar succession of conspicuous pollen abundance maxima an early phase with chenopodiaceae signaling the highest aridity a late phase with pistacia and gramineae in the mediterranean domain and tropical humid taxa in the arabian sea domain indicating conditions of mildest winter and wettest summer between these two phases the record for deciduous oak in the mediterranean and near east shows a continuous increase that points to rising moisture the chronology of this succession and its exact relationship with the marine isotopic record of global climate are established using marine cores the marine records dated by the ams 14 c method show that the chenopodiaceae phase correlates with the younger dryas chronozone globally dated 11 000 to 10 000 bp during which the climate reversed to quasi glacial conditions at least in the northern hemisphere they also show that the pistacia phase during which the mediterranean climate reached its seasonal optimum occurred from 9000 to 6000 14 c years bp boreal and early atlantic chronozones defined in nw europe in the first half of the holocene the oak pollen abundance increases rapidly from 10 000 to 9000 bp preboreal chronozone thus in terms of climate the younger dryas chronozone is regionally expressed by wide spread desert conditions as a cold and arid period during the pistacia phase the climate was most favourable both for plants that require frost free winters such as the mediterranean pistacia and those that need spring summer moisture such as gramineae at low annual moisture level seasonally 300 mm and deciduous oak at higher levels 600 mm all year without summer drought during the brief intermediary phase the climate changed drastically through an increase of winter temperature and of spring summer moisture the chronologies of the land cores however based on few 14 c dates show significant discrepancies with the marine based time frame these discrepancies imply a lack of coherence in the climate history of this mediterranean irano turanian region we propose using the chronology derived from the marine records for the entire region the local 14 c dates generally appear too old perhaps because of geological contamination of the material by older carbon

mediterranean quaternary sapropels an immediate response of the african monsoon to variation of insolation abstract in the subsurface of the east mediterranean sea eleven discrete basin wide organic rich black sapropels were deposited during the last 465 000 years they are dated by oxygen isotopic chronostratigraphy the most recent sapropel has been shown to be the consequence of heavy nile river summer floods due to increased monsoonal summer precipitation over ethiopia and not of scandinavian ice sheet meltwater influx into the east mediterranean sea as was previously believed while most sapropels were deposited during interglacials two thick sapropels formed during glacial periods as shown by their position in the oxygen isotopic stratigraphy and by their pollen record in core rc9 181 the new evidence presented here is that the sapropel sequence in this core including the two glacial sapropels correlates on a one to one basis with the highest values of an index of insolation on top of the atmosphere the concept of this index derives from an analysis of the african monsoon process the index variation is computed for the last 465 000 years from the caloric northern summer insolation in the tropical latitudes controlled by variations of the earth s orbital parameters it is conjectured that this index might be linked through the climate system to the monsoonal precipitation which in africa produces the nile river summer flood

quaternary neotectonics of the south aegean arc abstract the sedimentary and tectonic quaternary evolution of the south aegean arc has been interpreted from 8000 line km of sparker seismic reflection profiles the older parts of basins formed by e w trending faults and accumulated hemipelagic sediment younger active faulting trends nnw in the western part of the arc and ene in the eastern arc the ene trending faults record sinistral strike slip motion broadly parallel to the convergence direction of the aegean anatolian and african plates the north south faults in the western arc are similar to those on land in the south peloponnese chronology is estimated from sedimentation rates in cores and from stacked progradational units on basin margins controlled by eustatic changes in sea level the younger fault pattern developed at 0 6 0 8 ma in the western and central arc but progressively younger in the southeastern part of the arc the older basin fill with e w faults is of early quaternary and pliocene age an older regional unconformity corresponds to an early pleistocene unconformity in the cretan basin particularly in the area east of santorini faulting has resulted in startling changes in palaeogeography such that some areas were late pliocene basins positive features during the pleistocene and then subsided 600 m in the last 0 2 ma such rapid basin inversion resulted in uplift of stratified hemipelagic muds which were deformed by creep or failure so that debris flow deposits accumulated in valleys and ponded basins these fundamental tectonic changes in the past two million years indicate that much of the deformation resulting from the interaction of the eurasian african and anatolian aegean plates is taken up at the southern margin of the aegean microplate probably because subduction of the african plate has slowed as a result of collision of continental crust regional fault patterns are a consequence of spatially varying effects of subduction roll back

climatic forcing of eastern mediterranean deep water formation and benthic ecosystems during the past 22 000 years abstract lateglacial and holocene faunal and stable isotope records from benthic foraminifers in the eastern mediterranean sea ems suggest a high spatiotemporal variability of deep water oxygenation and biogeochemical processes at the sea floor during that time changes in the oxygenation and food availability of the deep sea ecosystems are closely linked to the hydrology of the ems borderlands they reflect orbital and suborbital climate variations of the high northern latitudes and the african monsoon system during the last glacial maximum cool surface waters and high evaporation resulted in maximum convection and oxic deep waters in all sub basins strong wind induced mixing fostered surface water production with seasonal phytodetritus fluxes during the glacial termination and the holocene oxygenation and food availability of deep sea benthic ecosystems were characterized by a pronounced regional differentiation local deep water formation and trophic conditions were particularly variable in the northern aegean sea as a response to changes in riverine runoff and black sea outflow during the interval of sapropel s1 formation in the early holocene average oxygen levels decreased exponentially with increasing water depth suggesting a basin wide shallowing of vertical convection superimposed by local signals in the northernmost aegean sea deep water ventilation persisted during the early period of s1 formation owing to temperature driven local convection and the absence of low salinity black sea outflow at the same time severe temporary anoxia occurred in the eastern levantine basin at water depths as shallow as 900 m this area was likely influenced by enhanced nutrient input of the nile river that resulted in high organic matter fluxes and related high oxygen consumption rates in the water column in the southern aegean and levantine seas we observe a gradual increase in deep water residence times preceding s1 formation by approximately 1 1 5 kyr once oxygen levels fell below a critical threshold the benthic ecosystems collapsed almost synchronously with the onset of s1 deposition the recovery of benthic ecosystems during the terminal phase of s1 formation is controlled by subsequently deeper convection and re ventilation over a period of approximately 1500 years after the re ventilation of the various sub basins had been completed during the middle and late holocene deep water renewal was more or less similar to recent rates during that time deep sea ecosystem variability was driven by short term changes in food quantity and quality as well as in seasonality all of which are linked to millennial scale changes in riverine runoff and associated nutrient input

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