assessment of the impact of climate and anthropogenic factors on holocene mediterranean vegetation in europe on the basis of palaeohydrological records abstract correlations between lake level and river activity records from the western mediterranean and palaeohydrological records from northern africa and central europe suggest a distinction in the western mediterranean region between an early holocene period characterised by cooler and moister conditions than at present favourable to temperate deciduous trees and after 5000 yr bp a later holocene period with a warmer and drier climate the second phase was favourable to the extension of evergreen sclerophyllous trees possibly reinforced by human activities these two successive holocene periods reflect orbitally induced changes in summer insolation furthermore superimposed on this general climatic trend century scale climatic oscillations punctuated the whole holocene period decreases in river activity in the western mediterranean region occurred at ca 11 500 10 500 9000 7000 4000 3000 2000 and 800 cal yr bp these decreases coincided with lake level lowering in jura eastern france and glacier retreat in the northern alps and could be associated with a temporary expansion of sclerophyllous trees this general pattern could have resulted from an alternatingly southward northward displacement of the atlantic westerly jet

monsoonal variability in the northeastern arabian sea during the past 5000years geochemical evidence from laminated sediments abstract a high resolution laminated sediment record from the oxygen minimum zone in the northeastern arabian sea off pakistan was studied to reconstruct climatic variations to infer the monsoon driven moisture history in the northeastern arabian sea during the past 5000 years we have used three types of independant proxies 1 varve thickness 2 stable isotope ratios of planktic foraminifera and 3 inorganic geochemical composition on the basis of these proxies we have subdivided the sedimentary record into five intervals the first time interval from 5000 to 3900 yr bp period i is dominated by summer monsoon activity deduced from ti al zr al k al and sr ca ratios and oxygen isotope data of planktonic foraminifera slightly enhanced winter monsoon conditions can be inferred for the period from 3900 to about 3000 yr bp period ii maximum precipitation during enhanced winter monsoon activity at about 3100 yr bp was followed by an onset of aridification at 3000 yr bp which continued until about 2000 2200 yr bp period iii the textural mineralogical and geochemical data suggest that this aridification was a gradual century scale process rather than an abrupt event comparison to late holocene records in nw and sw india the near east and tropical africa supports our interpretation that period iii from 3000 to 2000 yr bp is characterized by a gradual change in the atmospherical moisture budget over much of this area reduced monsoonal rainfall may be linked to variations of eurasian snow cover as deduced from varve thickness and element to al ratios period iv from 2000 to about 1500 yr bp is characterized by a summer monsoon dominated sequence with higher precipitation than during period iii the 18o record shows an abrupt shift at 2000 yr bp coinciding with an increase of varve thickness which suggests a cooling of surface waters in the northern arabian sea present day conditions in the makran area were established at 1500 yr bp period v based on inorganic geochemical data and meteorological records at several stations in the makran we conclude that period v is dominated by precipitation during the winter season here declined rainfall associated with the summer monsoon may be related to a less northward position of the intertropical convergence zone itcz during summer and a stronger influence of winter monsoon linked phenomenona

a record of holocene climate change from lake geochemical analyses in southeastern arabia lacustrine sediments from southeastern arabia reveal variations in lake level corresponding to changes in the strength and duration of indian ocean monsoon iom summer rainfall and winter cyclonic rainfall the late glacial holocene transition of the region was characterised by the development of mega linear dunes these dunes became stabilised and vegetated during the early holocene and interdunal lakes formed in response to the incursion of the iom at approximately 8500 cal yr bp with the development of c3 dominated savanna grasslands the iom weakened ca 6000 cal yr bp with the onset of regional aridity aeolian sedimentation and dune reactivation and accretion despite this reduction in precipitation the lake was maintained by winter dominated rainfall there was a shift to drier adapted c4 grasslands across the dune field lake sediment geochemical analyses record precipitation minima at 8200 5000 and 4200 cal yr bp that coincide with bond events in the north atlantic a number of these events correspond with changes in cultural periods suggesting that climate was a key mechanism affecting human occupation and exploitation of this region

stable isotope records of late quaternary climate and hydrology from mediterranean lakes the isomed synthesis lake isotope records can be used to assess the spatial coherency of late quaternary climate change across the circum mediterranean region we place modern and palaeo data within a simple conceptual lake response model to show that the isotope hydrology of most mediterranean lakes has been influenced strongly by water balance even in those systems that are chemically dilute i e freshwater 18o data on biogenic and endogenic carbonates from 24 lake basins are used to reconstruct multi millennial scale trends since the lgm while it is difficult to make direct comparisons between lake records in terms of single climatic parameters coherent regional isotopic trends can be identified during glacial times mediterranean lakes deposited carbonates isotopically heavier in 18o compared to the holocene partly due to source area effects isotopic enrichment was most marked during intervals corresponding to the h1 and younger dryas events confirming that late pleistocene cold stages in the north atlantic region were marked by aridity around much of the mediterranean almost all mediterranean lake records shifted to more depleted isotopic values during the last glacial interglacial transition lgit this shift is the reverse of the trend which characterised the same transition in lakes from northern and central europe and suggests that temperature changes were not an important direct driver of mediterranean lake isotopic records over glacial interglacial timescales in the early holocene many lakes in the eastern part of the region were more depleted isotopically than in recent millennia this corresponds with marine sapropel formation both chronologically and geographically and implies that increases in local rainfall contributed significantly to the creation of a freshwater lid and anoxia in the east mediterranean sea in contrast no such pattern is currently apparent from lake isotope records from the west mediterranean suggesting a possible nw se contrast in climate history during the holocene

palynology sedimentology and palaeoecology of the late holocene dead sea abstract palynological and sedimentological studies were performed at two holocene profiles in erosion gullies ze elim and ein feshkha which dissect the retreating western shore of the dead sea the aim of the project was to analyse possible links between climate lithology and vegetation development the section in ze elim shows both lacustrine and fluvial sediments whereas sedimentation at ein feshkha is predominantly lacustrine the ze elim profile previously used for paleo lake reconstruction provides an opportunity to compare climate triggered lake levels as paleo hydrological indicators and vegetation history by use of palynology the vegetation development in ze elim and ein feshkha is influenced by both climate and human impact the pollen record of ze elim begins in the pottery neolithic the section of ein feshkha in the late bronze age both records end in the middle ages the ze elim section is characterized by sedimentary hiati between the beginning of the chalcolithic period until the middle bronze age and within the late bronze age settlement periods during the middle bronze age iron age and hellenistic roman byzantine period are indicated by high values of anthropogenic indicators and or mediterranean trees collapses of agriculture which can be related to climate effects are evident during the late bronze age during the iron age and at the end of the byzantine period when the lake level curve indicates arid conditions a comparison of the two pollen records from different environments illustrates a more prominent influence of mediterranean vegetation and cultivated plants in the pollen diagram of ein feshkha the southern dead sea region at the desert fringe is more vulnerable to regional climate change

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

river inflow and salinity changes in the caspian sea during the last 5500 years abstract pollen spores and dinoflagellate cysts have been analysed on three sediment cores 1 8 1 4 m long taken from the south and middle basins of the caspian sea a chronology available for one of the cores is based on calibrated radiocarbon dates ca 5 5 0 8 cal ka bp the pollen and spores assemblages indicate fluctuations between steppe and desert in addition there are some outstanding zones with a bias introduced by strong river inflow the dinocyst assemblages change between slightly brackish abundance of pyxidinopsis psilata and spiniferites cruciformis and more brackish dominance of impagidinium caspienense conditions during the second part of the holocene important flow modifications of the uzboy river and the volga river as well as salinity changes of the caspian sea causing sea level fluctuations have been reconstructed a major change is suggested at ca 4 cal ka bp with the end of a high level phase in the south basin amongst other hypotheses this could be caused by the end of a late and abundant flow of the uzboy river now defunct carrying to the caspian sea either meltwater from higher latitudes or water from the amu daria a similar later clear phase of water inflow has also been observed from 2 1 to 1 7 cal ka bp in the south basin and probably also in the north of the middle basin

holocene climate change in the eastern mediterranean region a comparison of stable isotope and pollen data from lake golhisar southwest turkey stable isotope and pollen data from golhisar golu a small intramontane lake located in southwest turkey provide complementary records of holocene climate change modern oxygen and hydrogen isotope water data are used as a means of comparing present day isotope composition of the lake water to the past oxygen isotope composition of the lake water as calculated from 18o 16o ratios in calcite precipitated in the summer months despite the lake system being chemically dilute the modern isotope data clearly establish that the lake water is evaporated in relation to its spring input suggesting that the palaeo data can be interpreted primarily in terms of changing precipitation evaporation ratios 18o and 13c values from authigenic calcite through the holocene show predominantly negative values indicating climatic conditions wetter than today particularly notable are low depleted isotope values during the earliest holocene ca 10 600 8800 cal yr bp a period for which pollen data imply drier conditions than at present this divergence between pollen inferred and stable isotope palaeoclimate data is found in other east mediterranean lake sediment records and suggests that vegetation may have taken several millennia to reach climatic equilibrium at the start of the holocene isotopic fluctuations during the early to mid holocene 8800 5100 cal yr bp suggest oscillations between aridity and humidity higher 18o and 13c values for the second half of the holocene indicate generally drier conditions than during the period before ca 5100 cal yr bp although there is some evidence for increased humidity coinciding with pollen evidence for increasing human impact and intensification of agriculture notably during the so called beyehir occupation phase classical and early byzantine periods the modern trend towards aridity started about 1300 yr ago

mid to late holocene climate change in central turkey the tecer lake record the mineralogy and grain size distribution of sediments from tecer lake in central anatolia provides a 6000 year record of mid to late holocene climate trends and events correspondences between k

interdecadal variation in an antarctic sponge and its predators from oceanographic climate shifts during the 1960s there was extensive formation of anchor ice to depths of 30 meters at mcmurdo station antarctica during this period the sponge homaxinella balfourensis was rare as were its predators in that depth zone most of the existing sponges were killed by anchor ice during the 1970s anchor ice formation was reduced and there was a massive recruitment of homaxinella which covered as much as 80 percent of the substrata in that zone many predators appeared but did not control the sponge population and it continued to grow through that decade the early 1980s were characterized by ice formation and almost all of the homaxinella were eliminated leaving an order of magnitude more predators in that zone the interdecadal increases in anchor ice probably result from local upwelling of extremely cold deep water possibly in response to shifts in the strengths of regional currents

evironmental change in southwestern iran the holocene ostracod fauna of lake mirabad ostracod faunal data are presented from a sediment core taken from extant iranian lake mirabad ostracod faunal successions indicate relatively high concentrations of mainly nektonic taxa between c 9265 and 6505 cal 14c yr bp followed by lower concentrations of mainly benthic forms after 6505 cal bp these results suggest that lake levels were low during the early holocene and that water levels rose during mid holocene times notably after c 4048 cal 14c yr bp these findings confirm and consolidate palaeoclimatic inferences based on previously published pollen diagrams from the region but indicate an apparent timelag between the early to mid holocene forest advance and increased lake levels this may be explained by changes in precipitation evaporation ratios the increase in winter precipitation was sufficient to allow the expansion of arboreal vegetation but summer evaporation remained high this also gives support to the idea that the delayed readvance of forests in eastern turkey and western

petrological evidence for crustal thickening and extension in the serre granulite terrane calabria southern italy the paper presents the metamorphic trajectory recorded by metapelitic migmatites of the upper part of the hercynian lower continental crust of the serre southern calabria italy the relict minerals reaction textures and phase equilibria define a clockwise p t path the prograde metamorphism from temperature of about 500 c and pressure of 4 5 kbar to t 700 ca nd p 8 kbar stabilized the assemblage grt ky bt ms si 11ox 3 26 3 29 in the uppermost metapelites of the profile progressive heating led to h2o fluxed and dehydration melting first of ms then of bt at t 700 c in the stability field of sillimanite this process was followed by nearly isothermal decompression producing additional melt with a transition from grt to a grt crd stability field further decompression caused the formation of crd corona around garnet nearly isobaric cooling led to rehydration and retrogression across the stability field of andalusite up to the stability field of kyanite the lowermost metapelites of the studied profile have lost most of the memory of the prograde p t path they record decompression and cooling high temperature mylonites occur in which boudinage elongation and pull aparts characterize the porphyroclasts the pull aparts in the high t mylonites are filled with low p minerals crd spl the hercynian metamorphic trajectory and the microtextures are consistent with crustal thickening and subsequent extensional regime during extension an important tectonic denudation probably caused the isothermal decompression extension also occurred in post hercynian times as documented by pull aparts in sillimanite porphyroclasts filled with chloritoid within a low grade mylonite

late holocene lake levels of the dead sea this work presents a high resolution lake level record of the late holocene dead sea a hypersaline terminal lake whose drainage basin encompasses both mediterranean and hyperarid climatic zones the lake level curve reflects the regional hydrologic variations in the drainage basin which in turn represent the levant paleoclimates the curve is based on 46 radiocarbon ages of organic remains from well exposed sedimentary sequences along the dead sea shores these sequences record fluvial and lacustrine depositional environments the paleolakeshores are marked by shore ridges coarse sand units and aragonite crusts in the modern dead sea such features indicate the exact elevation of the shore the late holocene dead sea level fluctuated within the range of 390 to 415 m below sea level mbsl for most of the time the lake was below the topographic sill 402 mbsl separating the northern and southern basins of the dead sea and was confined to the deep northern basin nevertheless short term rises in the late holocene dead sea level caused the flooding of the shallow and flat southern basin highstands occurred in the second and first centuries b c and the fourth century a d during the roman and early byzan tine periods respectively in the eleventh and twelfth centuries a d during the crusader period and at the end of the nineteenth century a d the rises mark a significant change in the annual rainfall in the region which likely exceeded the instrumentally measured modern average the curve also indicates drastic drops that exposed the sedimentary sequences to erosion the oldest and probably deepest drop in the lake level culminated during the fifteenth and fourteenth centuries b c after a retreat from a higher lake stand the longest lowstand occurred after the byzantine period and continued at least until the ninth century a d this arid period coincided with the invasion of moslem arab tribes into the area during the seventh century a d the dramatic fall of the dead sea level during the twentieth century is primarily artificial and has been caused by the diversion of runoff water for the drainage basin but the magnitude is not considered exceptional for the late holocene although the past drops in the lake never exceeded the modern artificial drop rates they do represent extreme arid conditions that occurred frequently over the past several thousand years

palaeolimnology of lake zeribar iran and its climatic implications lake zeribar sediments covering the time period of the last 25 000 years were examined for the contents of seeds fruits characeae diatoms and molluscs reconstructions of the variations in the lake water level salinity and trophy suggest a sequence of climatic changes three pronounced stages of low and varying lake water level occurred ca 17 700 15 400 12 600 12 000 and 10 000 6000 cal yr bp some water level changes were correlated with variations in salinity the most pronounced increase of salinity occurred 17 700 15 700 and 12 600 12 000 cal yr bp and less distinct ones occurred about 6400 5900 and 2500 cal yr bp diatom assemblages indicated a strong increase of lake trophy ca 20 200 cal yr bp between 6000 and 5000 cal yr bp diatoms characteristic of eutrophy increased in core 63j and at about 3200 cal yr bp a distinct increase in mesotrophic forms occurred in core 70b the changes in the occurrence of various organisms indicate increased temperatures about 21 000 cal yr bp between 15 400 and 12 600 about 12 000 and about 11 700 cal yr bp the reduced occurrence or disappearance of some of them suggest temperature decreases about 17 700 15 400 and 12 600 12 000 cal yr bp

diatom based conductivity reconstruction and palaeoclimatic interpretation of a 40 ka record from lake zeribar iran sediment cores from lake zeribar in the zagros mounitains of western iran provide a record of changes in the diatom flora since about 40 ka conductivity transfer functionis applied to diatom records from the lake indicate generally higher conductivity during the last glacial maximum and lateglacial especially between 15 0 and 10 5 ka this observation is consistent with previous interpretations of relatively arid conditions during this interval based on the lake zeribar pollen records oscillations between high and lowconductivity states during this interval additionally suggest changes in precipitation associated with millennialscale climate events with relatively dry conditions during the younger dryas diatom inferred conductivity is relatively low throughout the holocene shifts in diatomn composition occur in the holocene record however minor variations in reconstrtucted conductivity are not considered significant

a high resolution late holocene lake isotope record from turkey and links to north atlantic and monsoon climate a high resolution proxy record of precipitation and evaporation variability through the past 1700 yr from 18o analysis of a varved lake sequence from central turkey shows rapid shifts between dry periods ad 300 500 and ad 1400 1950 and wetter intervals ad 560 750 and ad 1000 1350 changes are consistent with changes in instrumental and proxy records of the indian monsoon dry summers in the eastern mediterranean being associated with periods of enhanced monsoon rainfall in addition major shifts in the record are coherent with changes in north atlantic winter climate with cold wet periods in the alps occurring at times of dry turkish climate

the dune systems of the konya plain turkey their relation to environmental changes in central anatolia during the late pleistocene and holocene abstract several sand flats located on the northern shores of the late pleistocene palaeolake of the konya plain inner anatolia turkey are related to changes in lake levels in this paper the two main dune systems are mapped according to their geomorphological sedimentological and dynamic characteristics and their significance is discussed with regard to the environmental changes since the late pleistocene both at time of the former lake and during the drier periods of the holocene cross sections show the relationship of the dunes to the topography of the basement analyses of the sand fraction show distinct characteristics in size distribution quartz and shell contents wind erosion effects on the quartz grains and petrographic composition interpretation of the results coupled with information provided by the geomorphology of the dune systems studied in the field and from aerial photographs and satellite images highlights the importance and variations in time of local factors such as prevailing winds sand sources changes in lake levels and vegetation a chronology of the main sand fields is proposed based on the evidence of three main droughts during the upper pleistocene the older one much eroded maximum height 3 m covers a limestone surface at 50 m above the bottom of the dried lake an optical scanning luminescence osl date shows a last period of accumulation at 14 328 3220 years the younger one maximum height 12 m has moved over the emerged late pleistocene lacustrine marls an osl date gives an age of 5674 988 years for the last accumulation period evidence of very recent activation of this younger dune system is apparent as a result of overgrazing and excessive land reclamation a third period of dominant wind action and dune construction is responsible for the installation of a younger and thin dune field over the mid holocene lacustrine deposits of the karapinar lake the success of the stabilization programme of the dunes over the last 30 years shows that the last period of dune movement is not related to climate change but to overpressure on the land due to the needs and activities of an increasing population

a 5000 yr record of climate change in varved sediments from the oxygen minimum zone off pakistan northeastern arabian sea the upper holocene marine section from a kasten core taken from the oxygen minimum zone off karachi pakistan at water depth 700 m contains continuously laminated sediments with a sedimentation rate of 1 2 mm yr and a unique record of monsoonal climatic variability covering the past 5000 years our chronostratigraphy is based on varve counts verified by conventional and ams 14 c dating individual hemipelagic varve couplets are about 0 8 1 5 mm thick with light colored terrigenous laminae a deposited mainly during the winter monsoon alternating with dark colored laminae b rich in marine organic matter coccoliths and fish debris that reflect deposition during the high productivity season of the late summer monsoon august october precipitation and river runoff appear to control varve thickness and turbidite frequency we infer that precipitation decreased in the river watershed indicated by thinning varves after 3500 4000 yr b p this is about the time of increasing aridification in the near east and middle east as documented by decreasing nile river runoff data and lake level lowstands between turkey and northwestern india this precipitation pattern continued until today with precipitation minima about 2200 1900 yr b p 1000 yr b p and in the late middle ages 700 400 yr b p and precipitation maxima in the intervening periods as documented by spectral analysis the thickness of varve couplets responds to the average length of a 250 yr cycle a 125 yr cycle the gleissberg cycle of solar activity 95 yr and a 56 yr cycle of unknown origin higher frequency cycles are also present at 45 39 29 31 and 14 yr the sedimentary gray value also shows strong variability in the 55 yr band plus a 31 yr cycle because high frequency cyclicity in the enso band ca 3 5 and 5 yr is only weakly expressed our data do not support a straightforward interaction of the pacific enso with the monsoon driven climate system of the arabian sea

interpreting lake isotope records of holocene environmental change in the eastern mediterranean oxygen isotope records from lake sediment archives are becoming an increasingly common tool for palaeoenvironmental reconstruction we discuss their interpretation in the eastern mediterranean region with particular reference to three records zeribar van and eski acigol during the holocene the latter two records have been interpreted as controlled by changes in the precipitation to evaporation ratio and the first due to changes in precipitation seasonality in light of recent isotope work in the region and comparison with other proxy data from the same lakes we show both of these initial interpretations to be oversimplified careful interpretations of complex lake isotope systems are therefore required in order that palaeoclimatic inferences are drawn correctly

timing of atmospheric precipitation in the zagros mountains inferred from a multi proxy record from lake mirabad iran abstract a sediment core 7 2 m long from lake mirabad iran was examined for loss on ignition mineralogy oxygen isotopic composition of authigenic calcite and trace element composition of ostracodes to complement earlier pollen and ostracode assemblage studies pollen ostracode inferred lake level and high sr ca ratios indicate that the early holocene 10000 to 6500 cal yr bp was drier than the late holocene low 18 o values during this interval are interpreted as resulting from winter dominated precipitation characteristic of a mediterranean climate increasing 18 o values after 6500 cal yr bp signal a gradual increase in spring rains which are present today a severe 600 yr drought occurred at ca 5500 cal yr bp shortly after the transition from pistachio almond to oak forest during the late holocene two milder droughts occurred at about 1500 and 500 cal yr bp within the resolution of the record no drought is evident during the collapse of the akkadian empire 4200 3900 cal yr bp rather a decrease in 18 o values to early holocene levels may indicate the return to a mediterranean precipitation regime

holocene climate variability and cultural evolution in the near east from the dead sea sedimentary record abstract a comprehensive record of lake level changes in the dead sea has been reconstructed using multiple well dated sediment cores recovered from the dead sea shore interpreting the lake level changes as monitors of precipitation in the dead sea drainage area and the regional eastern mediterranean palaeoclimate we document the presence of two major wet phases 10 8 6 and 5 6 3 5 cal kyr bp and multiple abrupt arid events during the holocene the arid events in the holocene dead sea appear to coincide with major breaks in the near east cultural evolution at 8 6 8 2 4 2 3 5 cal kyr bp wetter periods are marked by the enlargement of smaller settlements and growth of farming communities in desert regions suggesting a parallelism between climate and near east cultural development