a penultimate glacial monsoon record from hulu cave and two phase glacial terminations oxygen isotope records of three stalagmites from hulu cave china extend the previous high resolution absolute dated hulu asian monsoon record from the last to the penultimate glacial and deglacial periods the penultimate glacial monsoon broadly follows orbitally induced insolation variations and is punctuated by at least 16 millennial scale events we confirm a weak monsoon interval between 135 5 1 0 and 129 0 1 0 ka prior to the abrupt increase in monsoon intensity at asian monsoon termination ii based on correlations with both marine ice rafted debris and atmospheric ch 4 records we demonstrate that most of marine termination ii the full rise in antarctic temperature and atmospheric co 2 and much of the rise in ch 4 occurred within the weak monsoon interval when the high northern latitudes were probably cold from these relationships and similar relationships observed for termination i we identify a two phase glacial termination process that was probably driven by orbital forcing in both hemispheres affecting the atmospheric hydrological cycle and combined with ice sheet dynamics

active tectonics and human survival strategies tectonic movements continuously remould the surface of earth in response to plate motion yet such deformation is rarely taken into account when assessing landscape change and its impact on human land use except perhaps as an occasional hazard to human life or a temporary disruption in the longer term parems of human history however active tectonics also create and sustain landscapes that can be beneficial to human survival forming a complex topography of potentially fertile sedimentary basins enclosed by mountain bard that can facilitate the control and exploitation of food resources especially animal prey we discuss the tectonic history of northwest greece and show how the paleolithic sites of the region are located to take advantage of tectonically created features at both a local and a regional scale we suggest that the association of significant concentrations of early paleolithic sites with tectonically active regions is not coincidental and that on the longer time spans of human biological evolution active tectonics has been an importam selective agent contributing to the development of the human species as an intelligent predator

the dole effect over the last two glacial interglacial cycles detailed measurements of 18 o of atmospheric oxygen performed on air trapped in the vostok ice cores antarctica are used to extend the record of the dole effect over two climatic cycles back to 240 kyr b p except for glacial terminations i and ii and for an unexpected minimum occurring around 175 kyr the dole effect shows small variations adole within 0 5 these small variations however show a well marked 23 kyr precessional periodicity thus confirming the results obtained by bender et al 1994a for the first climatic cycle to explain the minimum value reached around 175 kyr we invoke the possibility of a peak in the oceanic productivity linked to climatic events induced at low latitudes under glacial conditions

vegetation and climate changes during the last two glacial interglacial cycles in the western mediterranean a new long pollen record from padul southern iberian peninsula abstract a new sediment core from padul padul 15 05 provides a long and continuous sedimentary and paleoenvironmental record of the last 200 kyr here we present a detailed palynological study from this sedimentary sequence with new vegetation and paleoenvironmental data and a climatic interpretation for the last two climatic cycles from the southern iberian peninsula in the western mediterranean region pollen analysis from this core shows orbital scale vegetation oscillations mainly forced by precession and eccentricity pointing into insolation as the principal factor controlling vegetation changes at this latitude the last two glacial interglacial cycles from mis 6 to the present as well as stadial and interstadial phases are well represented and characterized by significant oscillations in mediterranean forest in the area but several differences with respect to other mediterranean long pollen records can be recognized some of these disparities between regions seem to be more related to different precipitation rates linked to the specific geographical features e g strong topographic relief than to latitudinal differences between the sites in addition a lake level reconstruction based on palynological data was developed and compared with the previous reconstruction from this record representing local environmental changes in the padul wetland that seems to be related to precipitation evapotranspiration balance and therefore to changes in regional climate conditions during glacial stadial conditions recorded by maxima in xerophytes the p e increased due to very low evapotranspiration resulting in high lake levels while during warmer interglacial interstadial phases except for the mis 5e mainly represented in this record by maxima in the mediterranean forest water level decreased as a result of high evapotranspiration exceeding precipitation input the comparison of the new padul 15 05 pollen record with the two previous palynological studies from padul shows significant differences mainly due to disagreements in the age control of the sequences this study shows that an accurate age depth model becomes essential when interpreting long paleoenvironmental and paleoclimate records

dancing to the rhythms of the pleistocene early middle paleolithic population dynamics in nw iberia duero basin and cantabrian region the northwest of iberia has yielded one of the most complete european middle paleolithic records despite this wealth of information very little is known about population dynamics during this period for that reason the main concern of this paper is to provide socio environmental models that may help explain early middle paleolithic emp population dynamics in nw iberia assessing to what extent they were shaped by climate forces the archaeological record is analyzed on the basis of the heuristics of ecological models already employed in the european pleistocene record but never at a regional scale in order to detect long term changes in the composition of emp populations and the environmental biological and sociocultural process influencing those changes according to the models proposed we have detected a long term population dynamic between mis 11 and mis 6 characterized by low environmental stress high biological productivity interaction among populations and sociocultural complexity eventually this population dynamic was broken due to an extreme climate phase in late mis 6 that had a profound impact on populations and sociocultural structures as a result the upper pleistocene population of nw iberia was concentrated in the cantabrian region this area became an isolated neanderthal glacial refugium that hosted a population with different origins and fragile long term demographic stability

dansgaard oeschger and heinrich event imprints in alboran sea paleotemperatures past sea surface temperature sst evolution in the alboran sea western mediterranean during the last 50 000 years has been inferred from the study of c37 alkenones in international marine global change studies md952043 core this record has a time resolution of 200 years allowing the study of millennial scale and even shorter climatic changes the observed sst curve displays characteristic sequences of extremely rapid warming and cooling events along the glacial period comparison of this alboran record with 18o from greenland ice greenland ice sheet project 2 core shows a strong parallelism between these sst oscillations and the dansgaard oeschger events five prominent cooling episodes standing out in the sst profile are accompanied by an anomalous high abundance of neogloboquadrina pachyderma sinistral which is confined to the duration of these cold intervals these features and the isotopic record reflect drastic changes in the surface hydrography of the alboran sea in association with heinrich events hl 5

the selection of sites for paleovegetational studies the judicious selection of sites for paleovegetational and paleoclimatic studies permits paleoecologists to answer specific research questions that go beyond primary descriptions of past vegetation we present a model that describes the relationship between basin size and pollen source area and predicts the proportions of local extralocal and regional pollen sampled by lake basins of different size the distinctive sampling properties of lakes peats and small hollows can be exploited to provide details of pattern in paleovegetation so long as attention is given to the limitations and problems of these types of sites combinations of site types in a single study most fully exploit the information contained in sediments

the sapropel record of the eastern mediterranean sea results of ocean drilling program leg 160 research on sediments recovered during ocean drilling leg 160 has concentrated on two issues the first concerned the stratigraphy of sapropel formation the second was oriented to clarify specific processes that explain sapropel origin progress has been made in the construction of stratigraphic composites out of sedimentary sequences from individual holes at each of the palaeoceanographic sites on the composites initial work has resulted in the establishment of high resolution and intermediate resolution stratigraphies for three sites 963 964 967 correlation of sedimentary cycles to astronomical insolation cycles extends the stratigraphies to sites 969 and 966 the sapropel occurrences in the marine and land sequences over the entire eastern mediterranean are correlated with the resolution that can be obtained from isotope studies groups of sapropels occurred simultaneously over the entire basin in detail however the temporal and facies patterns of sapropel sequences differ between individual sites and depositional basins the differences may be related to effects of water depth diagenesis and post depositional tectonic attenuation of sequences studies on the geochemistry and facies of sapropels agree that anoxic conditions favoured preservation of organic matter in sapropels caused the enrichment of trace metals associated with sapropels and helped to preserve primary sedimentary structures besides all evidence is consistent with elevated fluxes of organic matter and associated elements during sapropel events

reconciling diverse lacustrine and terrestrial system response to penultimate deglacial warming in southern europe unlike the most recent deglaciation the regional expression of climate changes during the penultimate deglaciation remains understudied even though it led into a period of excess warmth with estimates of global average temperature 1 2 c and sea level 6 m above pre industrial values we present the first complete high resolution southern european diatom record capturing the penultimate glacial interglacial transition from lake ioannina northwest greece it forms part of a suite of proxies selected to assess the character and phase relationships of terrestrial and aquatic ecosystem response to rapid climate warming and to resolve apparent conflicts in proxy evidence for regional paleohydrology the diatom data suggest a complex penultimate deglaciation driven primarily by multiple oscillations in lake level and provide firm evidence for the regional influence of abrupt changes in north atlantic conditions there is diachroneity in lake and terrestrial ecosystem response to warming at the onset of the last interglacial with an abrupt increase in lake level occurring 2 7 k y prior to sustained forest expansion with peak precipitation we identify the potentially important role of direct input of snow melt and glacial meltwater transfer to the subterranean karst system in response to warming which would cause rising regional groundwater levels this explanation and the greater sensitivity of diatoms to subtle changes in temperature reconciles the divergent lacustrine and terrestrial proxy evidence and highlights the sensitivity of lakes situated in mountainous karstic environments to past climate warming

climate and vegetation changes 180 000 to 345 000 years ago recorded in a deep sea core off portugal a new high resolution combined marine proxy pollen sequence from the portuguese margin md01 2443 enables direct comparison of ocean and ice volume changes with vegetation development in south west iberia during marine isotope stages mis 7 8 and 9 changes in sea surface conditions on both orbital and millennial time scales are closely mirrored by forest extent indicating a coherence of climate variability between the north atlantic and south west iberia deglacial warming at the start of mis 7 and 9 was interrupted by incursions of subpolar water masses at the site accompanied by reversals in tree population expansion during mis 7e and 9e the close relationship in timing and amplitude between vegetation and offshore conditions broke down early forest collapse points to pronounced cooling and aridification on land which although not accompanied by a change in water masses at the portuguese margin appears to have coincided with abrupt decreases in atmospheric methane concentration recorded in antarctic ice cores the most extreme glacial conditions of mis 8 occurred during the early part followed by an interval of warmer conditions and tree population expansion similar to 263 ka this has sometimes been considered as indicating an early deglaciation but the data presented here show that it was distinct from termination iii which occurred later in line with milankovitch forcing a sub orbital oscillation in both isotopic and pollen records is observed at the end of mis 7 ca 184 ka which appears to be coeval with a recently identified sea level high stand c 2006 elsevier b v all rights reserved

comparison of changes in vegetation in northeast greece with records of climate variability on orbital and suborbital frequencies over the last 450 000 years abstract a new direct pollen orbital tuning procedure based on a correspondence between changes in certain vegetation elements and march and june perihelion configurations is applied to the tenaghi philippon record northeast greece the development of a refined chronological scheme allows comparisons to be made with records of climate variability from the north atlantic as well as of global sea level ice volume and atmospheric co2 content on orbital frequencies the comparison reveals a close correspondence between relative ice volume extent and tree population size during glacial intervals during interglacial and interstadial periods the degree of forest development is more closely associated with high latitude insolation and related climate regimes rather than extent of residual ice volume on suborbital frequencies the greek record shows similar repeat times in peaks of steppe vegetation with north atlantic ice rafting events but the amplitude of this variability in the two records is not always proportional overall what emerges is that the major shifts in the relative abundance of forest v open vegetation communities at tenaghi philippon on orbital and suborbital frequencies over the last 450 000 years are coherent with high latitude changes affecting atmospheric and oceanic circulation glacial decreases in atmospheric co2 content contributed to the elimination of tree populations by exacerbating water stress conditions during arid intervals but do not appear to be the primary driver of the observed vegetation changes at this latitude variations in co2 levels in the order of 40 ppmv between different interglacial interstadials periods with adequate moisture availability appear to have had a limited effect on the nature and size of tree populations

onset of hudson strait heinrich events in the eastern north atlantic at the end of the middle pleistocene transition 640 ka 1 heinrich events are well documented for the last glaciation but little is known about their occurrence in older glacial periods of the pleistocene here we report scanning xrf and bulk carbonate 18o results from integrated ocean drilling program site u1308 reoccupation of deep sea drilling project site 609 that are used to develop proxy records of ice rafted detritus ird for the last 1 4 ma ca sr is used as an indicator of ird layers that are rich in detrital carbonate i e heinrich layers whereas si sr reflects layers that are poor in biogenic carbonate and relatively rich in detrital silicate minerals a pronounced change occurred in the composition and frequency of ird at 640 ka during marine isotope stage mis 16 coinciding with the end of the middle pleistocene transition at this time hudson strait heinrich layers suddenly appeared in the sedimentary record of site u1308 and the dominant period of the si sr proxy shifted from 41 ka prior to 640 ka to 100 ka afterward the onset of heinrich layers during mis 16 represents either the initiation of surging of the laurentide ice sheet lis off hudson strait or the first time icebergs produced by this process survived the transport to site u1308 we speculate that ice volume i e thickness and duration surpassed a critical threshold during mis 16 and activated the dynamical processes responsible for lis instability in the region of hudson strait we also observe a strong coupling between ird proxies and benthic 13c variation at site u1308 throughout the pleistocene supporting a link between iceberg discharge and weakening of thermohaline circulation in the north atlantic

four climate cycles of recurring deep and surface water destabilizations on the iberian margin centennial climate variability over the last ice age exhibits clear bipolar behavior high resolution analyses of marine sediment cores from the iberian margin trace a number of associated changes simultaneously proxies of sea surface temperature and water mass distribution as well as relative biomarker content demonstrate that this typical north south coupling was pervasive for the cold phases of climate during the past 420 000 years cold episodes after relatively warm and largely ice free periods occurred when the predominance of deep water formation changed from northern to southern sources these results reinforce the connection between rapid climate changes at mediterranean latitudes and century to millennial variability in northern and southern polar regions

sea level during the penultimate interglacial period based on a submerged stalagmite from argentarola cave italy accurate constraints are presented for the absolute age duration and sea level for the highstand corresponding to marine isotope stage mis 7 1 our work is based on a stalagmite collected in a currently submerged cave from italy argentarola cave flooding of this coastal cave is clearly marked within the stalagmite by a thick marine overgrowth of serpulid worms precise uranium thorium u th ages measured by thermal ionization mass spectrometry suggest that the stalagmite growth varied in phase with climate during mis 7 2 and mis 6 the penultimate glacial period in addition the period of marine transgression is bracketed between 202 and 190 kyr bp defining a mis 7 1 duration of 11 2 kyr comparison with previous studies provides a new constraint on the sea level during mis 7 1 that has approximately remained between 318 and 39 m relative to present sea level the timing of the mis 7 1 highstand is in full agreement with the specmap chronology which contrasts with the growing body of evidence showing a significant phase difference for mis 5 5 a tempting conclusion is that second order sea level highstands such as mis 7 1 may be purely driven by astronomical changes in contrast with major terminations such as termination ii atmospheric co2 levels may partly explain this contrast since the two sea level transitions mis 7 2 7 1 and mis 6 5 5 are characterized by very different co2 rises 20 vs 100 ppm fl 2002 elsevier science b v all rights reserved

vegetation history of the penultimate glacial period marine isotope stage 6 at ioannina north west greece the vegetational history of the penultimate glacial period marine isotope stage mis 6 c 185 135 ka has remained relatively unexplored here we present a new record from the ioannina basin north west greece which constitutes the highest resolution terrestrial pollen record for this interval produced to date it shows that the vegetation history of mis 6 in this region can be divided into two parts an early period 185 155 ka with pronounced oscillations in tree population extent and a later period 155 135 ka with much smaller tree populations and subdued oscillations this pattern is analogous to the mis 3 mis 2 division during the last glacial in the same sequence although the early part of mis 6 had larger pinus populations and fewer temperate trees relative to the equivalent interval in mis 3 this implies cooler and wetter conditions which is somewhat counterintuitive given the high summer insolation during mis 6e but is in line with other palaeoclimatic evidence from the mediterranean comparison with north atlantic records suggests that despite the absence of pronounced iceberg discharges during mis 6 north atlantic millennial scale variability had a significant downstream impact on tree populations in north west greece copyright c 2011 john wiley sons ltd

rapid environmental changes in southern europe during the last glacial period oxygen isotope records from greenland ice cores1 2 indicate numerous rapid climate fluctuations during the last glacial period north atlantic marine sediment cores show comparable variability in sea surface temperature and the deposition of ice rafted debris3 4 5 in contrast very few continental records of this time period provide the temporal resolution and environmental sensitivity necessary to reveal the extent and effects of these environmental fluctuations on the continents here we present high resolution geochemical physical and pollen data from lake sediments in italy and from a mediterranean sediment core linked by a common tephrochronology our lacustrine sequence extends to the past 102 000 years many of its features correlate well with the greenland ice core records demonstrating that the closely coupled ocean atmosphere system of the northern hemisphere during the last glacial4 extended its influence at least as far as the central mediterranean region numerous vegetation changes were rapid frequently occurring in less than 200 years showing that the terrestrial biosphere participated fully in last glacial climate variability earlier than 65 000 years ago our record shows more climate fluctuations than are apparent in the greenland ice cores together the multi proxy data from the continental and marine records reveal differences in the seasonal character of climate during successive interstadials and provide a step towards determining the underlying mechanisms of the centennial millennial scale variability

effective precipitation in southern spain 266 to 46 ka based on a speleothem stable carbon isotope record abstract we present the longest duration directly dated terrestrial palaeoclimate record from the western mediterranean region a flowstone speleothem from gitana cave southeast spain the main phase of growth was 274 to 58 ka dated by multi collector inductively coupled plasma mass spectrometry mc icpms u series methods effective precipitation which we consider primarily responsible for flowstone calcite 13 c variations measured at 300 m resolution was higher during interglacials associated with marine oxygen isotope stages mis 7 and 5 and lower during glacial mis 6 there is a close correspondence between speleothem 13 c and sea surface temperature sst estimates from adjacent atlantic ocean cores during mis 6 which implies that oceanic conditions are critical in controlling the western mediterranean terrestrial moisture balance during glacial periods other features of our record such as the sequence of termination ii warming moistening between approximately 133 and 127 ka including a pause around 130 128 ka and the lagged termination of mis 5 warm intervals 5e 5c and 5a are similar to other terrestrial records within the mediterranean basin indicating climate synchroneity along the northern mediterranean coast the gitana cave region also may have been a refugium for temperate species during short lived cold arid periods during mis 5

orbital and millennial antarctic climate variability over the past 800 000 years a high resolution deuterium profile is now available along the entire european project for ice coring in antarctica dome c ice core extending this climate record back to marine isotope stage 20 2 800 000 years ago experiments performed with an atmospheric general circulation model including water isotopes support its temperature interpretation we assessed the general correspondence between dansgaard oeschger events and their smoothed antarctic counterparts for this dome c record which reveals the presence of such features with similar amplitudes during previous glacial periods we suggest that the interplay between obliquity and precession accounts for the variable intensity of interglacial periods in ice core records

sea land oxygen isotopic relationships from planktonic foraminifera and speleothems in the eastern mediterranean region and their implication for paleorainfall during interglacial intervals the oxygen and carbon stable isotope compositions of cave speleothems provide a powerful method for understanding continental climate change here we examine the question of the regionality of this isotopic record and its linkage with the marine isotopic record in the eastern mediterranean em region the study presents a new accurately dated 250 kyr 18o and 13c record determined from speleothems of the peqiin cave northern israel its comparison with the continuous 185 kyr isotopic record of the soreq cave speleothems from central israel reveals striking similarities thus a strong regional climatic signal brought about by variations in temperature and rainfall amount is reflected in both cave records low 18o minima in the peqiin profile for the last 250 to 185 kyr period interglacial marine isotopic stage 7 match the timing of sapropels 9 to 7 and are indicative of high rainfall in the em region at these times the combined soreq and peqiin 18o record for the last 250 kyr excellently matches the published globigerinoides ruber g ruber marine 18o record for the em sea with the isotopic compositional difference g ruber speleothems remaining relatively constant at 5 6 0 7 thus establishing for the first time a robust exploitable link between the land and the marine isotopic records the correspondence of low 18o speleothem values and high cave water stands with low g ruber 18o values during interglacial sapropel events indicates that these periods were characterized by enhanced rainfall in the em land and sea regions by use of sea surface temperatures derived from alkenone data as a proxy for land temperatures at the soreq cave we calculate the paleorainfall 18o values and its amounts maximum rainfall and lowest temperature conditions occurred at the beginning of the sapropel events and were followed by decrease in rainfall and increase in temperatures leading to arid conditions the record for the last 7000 yr shows a trend toward increasing aridity and agrees well with climatic and archeological data from north africa and the middle east

phase relationships between millennial scale events 64 000 24 000 years ago a core recovered on the iberian margin off southern portugal can be correlated with greenland ice cores using oxygen isotope variability in planktonic foraminifera which closely matches the ice core records of temperature over greenland our age model identifies the base of every interstadial between 64 000 and 24 000 years ago and uses the greenland ice core project grip timescale the oxygen isotope signal in benthic foraminifera on this grip based timescale is quite different from the planktonic record and resembles the temperature record over antarctica when this is synchronized with greenland using the record of methane in the atmospheric air in the polar ice cores we interpret the benthic record as indicating significant fluctuations in ice volume during millennial events and we suggest that antarctic temperature changed as a function of ice volume

the lateglacial and holocene environmental history of the ioannina basin north west greece this study centres on palaeoenvironmental analysis of the upper part of a long core from the partially drained tectonic ioannina basin north west greece the data span the lateglacial and holocene and comprise pollen mollusc magnetic susceptibility loss on ignition and particle size analyses these augment previously published ostracod and stable isotope data from the same sediment sequence the age model for the sequence is based on 19 ams dates five of which were obtained using a novel procedure for the separation of microcharcoal from sediment the pollen data suggest that although temperate woodland expanded at the beginning of the lateglacial only limited woodland contraction occurred during the younger dryas chronozone despite strong evidence for a sharp drop in sea surface temperature in the neighbouring adriatic at this time in contrast large scale vegetational and sedimentological changes occur in concert during the holocene some of which may be ascribed to human impact comparison with other records from the ioannina basin suggests that previous more littoral pollen sequences did not constitute a wholly representative record of lateglacial and holocene vegetational change

ecological thresholds and patterns of millennial scale climate variability the response of vegetation in greece during the last glacial period the regional expression of millennial scale climate variability during the last glacial is examined with particular reference to the vegetation response in greece inspection of three pollen records from contrasting bioclimatic areas suggests that differences in the magnitude of cold events as recognized in the north atlantic and western mediterranean are expressed in terms of tree population changes only in areas with a range of favorable habitats by contrast records from sites where populations approach their tolerance threshold do not appear to resolve differences in the amplitude of the climate oscillations understanding the importance of local factors in modulating the biological response to climate change is critical when attempting to establish the spatial pattern of millennial variability

duration of last interglacial conditions in northwestern greece a new astronomical calibration method for long pollen records from southern europe is applied to the last interglacial interval of the ioannina sequence northwest greece this shows that the last interglacial in this region as defined by the presence of forest communities lasted c 15 500 years from 127 300 to 111 800 yr b p interglacial conditions developed within marine isotope sub stage mis 5e and persisted into mis 5d lagging changes in global ice volume

synchroneity between marine and terrestrial responses to millennial scale climatic variability during the last glacial period in the mediterranean region land sea climatic proxies have been obtained from the last glacial section of images core md95 2043 western mediterranean sea vegetation and alkenone derived sst curves indicate rapid 150 years and synchronous terrestrial and marine climatic changes paralleling the dansgaard oeschger d o climatic variability over greenland this frequency of climate change can be related to shifts between the two modes of operation of the north atlantic oscillation nao transfer functions applied to the pollen data indicate that there was an amplification of the climatic signal during heinrich events hes in comparison with other d o stadials the development and persistence of both scandinavian and atlantic mobile polar highs over southwestern europe may explain the extreme cooling 10 c and dryness 400 mm during heinrich events 5 and 4 in the mediterranean region comparison of the results of core md95 2043 with similar climatic data from images core md95 2042 located off portugal indicates that thermal and precipitation gradients occurred between the mediterranean and the atlantic sides of iberia within hes hes 4 and 5 are associated with more humid conditions in the atlantic by 200 mm than in the mediterranean site as is the case at the present time this comparison also illustrates the different behaviour of these areas during the d o stadials in contrast with the mediterranean site the atlantic site shows similar precipitation and temperature drops for all the d o stadials including those related to the hes here we propose the operation of different mobile polar highs mph as the driving mechanism for this difference in behaviour between the atlantic and mediterranean sides of iberia hes are related to a stronger influence of the scandinavian mph forcing a severe aridification and cooling of the full iberian peninsula the atlantic mph may have been dominant during the other stadials which would preferentially affect southwestern iberia

impact of multiscale modelling on predicted porosity and permeability distributions in the fluvial deposits of the upper lunde member snorre field norwegian continental shelf

the response of nw iberian vegetation to north atlantic climate oscillations during the last 65 kyr pollen and oceanographic data from deep ocean core md95 2039 provide a centennial to millennial scale record of conditions offshore and of the vegetation of north west iberia for the period 10 65 ka the planktonic oxygen isotope record of this core reflecting predominantly sea surface temperature sst shows a pattern of millennial scale oscillations that is very similar to climatic changes recorded by the greenland ice core records over the same interval in turn tree populations show a pattern of rapid expansions and contractions that follow the pronounced and abrupt isotopic shifts recorded offshore through marine isotope stage mis 3 this millennial scale pattern of vegetation change alternating between steppe and open woodland is superimposed on a longer term pattern of shrinking ericaceous heathland and decreasing size of successive interstadial tree populations trees persisted during the last glacial maximum lgm at greater abundance than during many of the coldest episodes of mis 3 this agrees with the marine data which indicate that lgm sea surface temperatures here were significantly warmer than the minima recorded in mis 3 our combined marine terrestrial record together with data from nearby sequences provides a stepping stone between terrestrial sequences and the greenland ice core and north atlantic marine records this will permit a better understanding of the behaviour of vegetation across different regions at several scales of climatic forcing

the nature of millennial scale climate variability during the past two glacial periods periodic iceberg discharges during the last glacial period led to a slowdown of the atlantic meridional overturning circulation sediment records from the portuguese margin show that similar events punctuated the penultimate glacial period as well although their duration and broader climatic impacts were modified by different background climate conditions during the last glacial period iceberg discharges into the north atlantic disrupted the meridional overturning circulation leading to cooling in the northern hemisphere and warming in antarctica1 2 this asymmetric response can be explained by a bipolar see saw mechanism3 4 5 whereby changes in the strength of the meridional overturning circulation lead to changes in the interhemispheric heat transport it is unclear however to what extent the response of the overturning circulation is a function of freshwater flux and boundary climate conditions4 here we use foraminiferal isotope and pollen records from the portuguese margin to reconstruct surface and deep water hydrography and atmospheric changes during the last and penultimate glacial periods when we compare our records with temperature reconstructions from antarctica6 we find that the bipolar see saw was a characteristic feature of both glacial periods however the comparison also underlines the dependence of the bipolar see saw on background climate and magnitude of iceberg discharge it also suggests that an intensified hydrological cycle may lead to a weaker overturning circulation with a smaller disruption threshold and extended north atlantic stadial durations

tephra correlations and climatic events between the mis6 5 transition and the beginning of mis3 in theopetra cave central greece abstract three cryptotephra layers associated with important periods of climatic change were identified in the middle palaeolithic sequence of theopetra cave greece the lower cryptotephra layer thp tii5 is correlated with the p 11 pantellerian eruption dated to 128 131 ka this cryptotephra postdates a thick sequence of combustion layers that show a complex vegetation succession quite similar to that of the last deglaciation succession in the cave two other cryptotephras thp tii10 and thp tii12 are correlated with the nisyros upper pumice and the pantellerian y6 green tuff dated to 50 ka and 45 7 ka respectively this sequence confirms the position of the nisyros upper tephra below the pantellerian green tuff in the volcanic event stratigraphy of the mediterranean moreover these two upper cryptotephras bracket an extended combustion layer with interstadial vegetation characteristics that may be coincident with the complex greenland interstadial 13 14 on the basis of this new chronology it can be deduced that the intensity of occupation and presence or absence of humans in the cave were closely related to climatic changes in addition a remarkable similarity in the pattern of occupational intensity during the last two deglaciations can be suggested

relation between low latitude insolation and δ18o change of atmospheric oxygen for the last 200 kyrs as revealed by mediterranean sapropels the isotopic ratio of atmospheric o2 18oatm deduced from ice cores displays large fluctuations during climatic cycles these are caused principally by changes in the oxygen isotopic ratio of sea water 18osw and changes in the biosphere and in the hydrological cycle as both 18oatm and 18osw coincide closely over the last 135 kyr bp it is generally believed that 18oatm is driven mainly by 18osw here we focus on the major discrepancy which arises between those two signals during the prior isotopic glacial stage 6 around 175 kyr bp discrepancy which calls into question the role of changes in 18osw as the driving mechanism for 18oatm we present arguments based on the occurrence and pollen content of mediterranean sapropels for another source of the 18oatm change insolation at low latitudes via hydrosphere biosphere activity

mediterranean pluvial periods and sapropel formation over the last 200 000 years abstract three mediterranean deep sea cores have been studied to reconstruct the hydrological conditions at the time of deposition of interglacial and glacial sapropels during the time interval 200 60 kyr bp the isotopic and sea surface temperature records of planktonic foraminifera were used to estimate the oxygen isotopic composition of surface water w in the tyrrhenian sea and levantine basin our results show a strong w salinity decrease in both basins associated with each sapropel these w decreases reflect a drastic change in the local freshwater budget and were comparable to that observed during the last sapropel s 1 centred at ca 8 kyr bp a strong precipitation increase transformed the whole mediterranean sea into a non concentration basin the low surface salinity was responsible for the water column stratification while nutrients brought in by the runoff enhanced productivity it resulted in a significant reduction in the rate of deep water oxygenation and sapropel formation in the eastern basin in addition the mediterranean sea 18 o record is very similar to that of the bay of bengal as the latter is very sensitive to the summer monsoon rain this similarity suggests that both glacial and interglacial sapropels result from enhanced monsoon like precipitation due to an increase in summer insolation driven by precession variations

simulation of intense monsoons under glacial conditions paleoenvironmental and paleoclimatological proxy data indicate that strong continental monsoons took place under glacial conditions during marine isotopic stage 6 5 175 ka bp so far no climate model has explored the possible coexistence of glacial conditions at mid and high latitudes and of interglacial monsoons in the tropics here we use an atmospheric general circulation model and clearly demonstrate that high insolation can generate increased monsoon activity even with surface glacial conditions our experiments show that indian and african monsoons at 175 ka were stronger than nowadays and induced an increase in outflow of the nile river to the mediterranean sea this freshwater supply combined with the local low glacial evaporation may explain the stagnation of the eastern mediterranean sea leading to the deposit of sapropel s6 our simulations show also increased surface winds in the northern atlantic and pacific oceans which may have affected the bioproductivity in these areas

millennial climatic instability during penultimate glacial period recorded in a south western france speleothem abstract this study focuses on an earlier mis marine isotopic stage 6 flowstone deposit vil car 1 core villars cave sw france that recorded millennial scale climatic events this speleothem provides a high resolution record of the penultimate glacial period on mid latitude land the flowstone high growth rate and the episodes with depleted calcite 13 c c values suggest that marine isotopic substage 6e environmental conditions were relatively warm and humid its 13 c c profile clearly displays five main climatic oscillations from 177 to 165 ka correlated with stadial interstadial events similarly to the mis3 period the transitions in between those interstadials and stadials are characterised by abrupt changes and intra interstadial variability is observed

african monsoons an immediate climate response to orbital insolation the croll milankovitch astronomical theory of climate1 3 has received strong support from the evidence of a linear climatic forcing by obliquity and precession although nonlinearity had to be assumed for eccentricity4 5 moreover interglacials have appeared to be controlled by the orbital insolation6 although a phase shift of 6 000 5 000 yr is seen between an astronomical climate index and terrestrial climate indicators dominated by the northern ice sheet dynamics climate proxy data of low latitudes are less directly dependent on the ice sheets here it is shown that during the past 464 000 yr african monsoons signalled by the east mediterranean sapropels were heaviest always and only when a northern summer monsoon index computed from the orbital variation of insolation reached maximum values this occurred during all the interglacials but also twice during glacial periods thus tropical aridity is not the single climatic pattern of glacial periods an immediate terrestrial climate response to orbital variations of insolation is established

climate variability in northwest greece during the last interglacial isotopic and palynological data over the period 115 000 to 135 000 years ago from a lacustrine sequence in northwest greece show distinct oscillations during the intervals leading into and out of the full interglacial whereas in between changes were less pronounced but included a brief fluctuation after peak interglacial conditions temperatures decreased and precipitation increased in a series of steps these data suggest that eemian climate variability was similar to that of the holocene both in terms of amplitude and possibly of pacing

middle pleistocene cold stage climates in the mediterranean new evidence from the glacial record abstract a major reduction in summer temperatures during a middle pleistocene glacial cycle caused the most extensive glaciation recorded in the mediterranean region glaciers in the mountains of greece formed during marine isotope stage mis 12 474 000 427 000 years bp under climatic conditions characterised by mean summer temperatures at least 11 c cooler than today and annual precipitation of 2300 mm at the equilibrium line altitude 1741 m a s l this represents the coldest mean summer temperatures recorded in greece during at least the last 430 000 years later pleistocene glaciations mis 6 and 5d 2 were characterised by warmer summer temperatures and higher annual precipitation

abrupt temperature changes in the western mediterranean over the past 250 000 years a continuous high resolution western mediterranean sea surface temperature sst alkenone record spanning the past 250 000 years shows that abrupt changes were more common at warming than at cooling during marine isotope stage mis 6 sst oscillated following a stadial interstadial pattern but at lower intensities and rates of change than in the dansgaard oeschger events of mis 3 some of the most prominent events occurred over miss 5 and 7 after prolonged warm periods of high stability climate during the whole period was predominantly maintained in interglacial interstadial conditions whereas the duration of stadials was much shorter

orbital signatures and long term vegetation patterns in the mediterranean abstract an attempt is made to explore the relation between vegetation phases and orbital configurations by comparing long pollen sequences from the mediterranean region and astronomical curves on the basis of their independent chronologies three recurring patterns emerge from this comparison i all intervals with perihelion passage occurring during northern winter were associated with significant contractions of tree populations ii all temperate stage expansions of certain mediterranean vegetation elements occurred when perihelion passage was in summer and iii temperate stage forests reached maximum extent at times of autumn perihelion of these patterns the first corresponds to extreme dry cold episodes culminating at times of march perihelion and the second to maximum summer temperature and evaporation regimes following june perihelion the third associated with the occurrence of september perihelion appears to be more diffuse both in time and space possibly reflecting local variations in hydrological regimes the consistency of at least the first two cases provides some support for the notion that certain recurring vegetation patterns appear to be a result of climate changes linked to specific orbital signatures this could eventually lead to the development of improved terrestrial chronologies through astronomical tuning

combined marine proxy and pollen analyses reveal rapid iberian vegetation response to north atlantic millennial scale climate oscillations abstract a deep sea sediment core from the western portuguese margin has provided a continuous high resolution record of millennial scale climatic oscillations during the interval 9000 65 000 yr b p pollen analysis of the same sequence allows direct in situ assessment of the phase relationship between the north atlantic climate system and vegetation changes on the adjacent landmass this demonstrates for the first time that variability in nw iberian tree population size closely tracked millennial scale climate variability

northern hemisphere forcing of climatic cycles in antarctica over the past 360 000 years the milankovitch theory of climate change proposes that glacial interglacial cycles are driven by changes in summer insolation at high northern latitudes the timing of climate change in the southern hemisphere at glacial interglacial transitions which are known as terminations relative to variations in summer insolation in the northern hemisphere is an important test of this hypothesis so far it has only been possible to apply this test to the most recent termination because the dating uncertainty associated with older terminations is too large to allow phase relationships to be determined here we present a new chronology of antarctic climate change over the past 360 000 years that is based on the ratio of oxygen to nitrogen molecules in air trapped in the dome fuji and vostok ice cores this ratio is a proxy for local summer insolation5 and thus allows the chronology to be constructed by orbital tuning without the need to assume a lag between a climate record and an orbital parameter the accuracy of the chronology allows us to examine the phase relationships between climate records from the ice cores and changes in insolation our results indicate that orbital scale antarctic climate change lags northern hemisphere insolation by a few millennia and that the increases in antarctic temperature and atmospheric carbon dioxide concentration during the last four terminations occurred within the rising phase of northern hemisphere summer insolation these results support the milankovitch theory that northern hemisphere summer insolation triggered the last four deglaciations

speleothem record from pentadactylos cave cyprus new insights into climatic variations during mis 6 and mis 5 in the eastern mediterranean abstract a new paleoclimate record from cyprus gives valuable insights into climatic variations during marine isotope stages mis 6 5 for the east mediterranean region two stalagmites from pentadactylos cave in the kyrenia mountain range 800 m altitude in cyprus grew from 174 6 0 7 to 112 2 0 5 ka bp with major hiatuses at 163 142 and 132 128 ka during early mis6 the stalagmite suggests through a relatively low growth rate 57 5 mm ka and variable but rather negative d18o that climate conditions were highly variable on a millennial scale with wet and cold climate conditions during sapropel 6 deposition at the end of mis6 141 132 ka growth rate varied from 123 to 18 mm ka and less negative 18 o c suggests general dry cold conditions followed by a growth stop during h11 the onset of mis5e is marked by the highest growth rate 217 mm ka the most negative 18o values at the onset and during the eemian wet period in cyprus are driven mostly by the source effect sapropel 5 and enhanced rainfall amounts stable conditions during mis 5e were rather short as shown in the growth and isotopic signal consistent with other em records after 122 ka growth decreased drastically 8 2 mm ka and a slow deterioration of the soil cover is suggested from continuously less negative 13c values fluid inclusion d18o shows a clear shift 4 5 between end mis 6 and mis 5e clumped isotopes measurements indicate kinetic effects between calcite and water of up to 1 after correction for kinetic effects using 47 a minimum estimate for the mis 6 5 temperature shift in the em is ca 9 c similarly drastic changes in rainfall amounts are inferred from measured fluid inclusion and calculated water d18o

petrography chemistry and isotopic ages of peninsular gneiss dharwar acid volcanic rocks and the chitradurga granite with special reference to the late archean evolution of the karnataka craton southern india abstract new petrographic major and trace element and isotopic age data are presented for four suites of rocks from the low to medium grade part of the south indian archaean craton in central karnataka two suites are from the peninsular gneiss basement to the late archaean dharwar supergroup the third is a suite of dharwar potassic rhyolites and the fourth is from the chitradurga granite which has intrusive contacts with the dharwar supergroup the chikmagalur granite granodiorite which with its host gneisses forms part of the basement peninsular gneiss to the dharwar supergroup in the bababudan basin yields rb sr and pb pb whole rock isochron dates of 3080 110 ma and 3175 45 ma respectively an initial 87 sr 86 sr ratio of 0 7013 0 0009 and a 1 value 238 u 204 pb of 7 98 host tonalitic gneisses to the chikmagalur granite give an rb sr whole rock isochron date of 3060 160 ma with an initial 87 sr 86 sr ratio of 0 7015 0 0004 and a pb pb whole rock isochron date of 3190 100 ma with a model 1 value of 8 00 a suite of granites and granodioritic tonalitic gneisses chitradurga granitic rocks and gneisses forming part of the peninsular gneiss basement to the dharwar supergroup west of the chitradurga belt yields rb sr and pb pb whole rock isochron dates of 2970 100 ma and 3028 28 ma respectively with an initial 87 sr 86 sr ratio of 0 7035 0 0013 and a model 1 value of 7 62 the suite of dharwar acid volcanic rocks from north of honnali defines a poorly fitted 207 pb 206 pb linear array mswd 15 8 which gives an apparent age of 2565 28 ma and a model 1 value of 7 46 the poor fit of this isochron shows that a closed system was not maintained a conclusion supported by high k abundances which are attributed to a syn or post magmatic ion exchange process the chitradurga granite which intrudes the older rocks of the dharwar supergroup in the chitradurga belt yields a well fitted pb pb whole rock isochron date of 2605 18 ma with a model 1 value of 7 68 the u pb relations in these suites from karnataka are in marked contrast with the commonly severe u depletion and consequently unradiogenic pb isotopic compositions observed in deeply eroded high grade archaean gneiss terranes such as those bordering the north atlantic this contrast indicates that the cratonic rocks in central karnataka represent a relatively high level in the original archaean continental crust

seven ambiguities in the mediterranean palaeoenvironmental narrative abstract a review of seven outstanding issues on mediterranean palaeoenvironments is presented these are related to the dominant orbital pacing of climate variability the length of the interglacial vegetation succession the influence of the african summer monsoon the seasonality of precipitation during boreal insolation maxima the moisture balance during glacial maxima and the appearance of the mediterranean type climate rhythm and evolution of mediterranean sclerophyllous plants what emerges is that 1 marine 18oplanktonic and sst records show that precession has been a fundamental tempo of mediterranean climate change representing both a low latitude signal runoff from north africa and the direct influence of insolation at mediterranean latitudes but high latitude glacial effects 41 kyr and 100 kyr cycles became superimposed after 2 8 ma sapropel and dust deposition patterns in marine cores reveal that obliquity also has an effect on mediterranean climate through dry wet oscillations which are independent of glacial interglacial variability 2 the temperate part of interglacial vegetation succession has a duration of approximately half a precession cycle this persisted during the interval of obliquity dominated glacial cycles 2 8 1 ma with distinct forest successions following the precessional cycles however these are not always separated by an open vegetation phase because of minimal ice growth producing an impression of a prolonged interglacial forest interval 3 the effect of an enhanced african monsoon during summer insolation maxima has been mainly indirect in terms of nile discharge and runoff along the north african coast leading to increased freshwater input into the mediterranean sea reduced deep water ventilation and sapropel deposition 4 the notion of an accentuated summer rain regime in the northern mediterranean borderlands also contributing to a freshening of the mediterranean sea during boreal insolation maxima is not supported by the available evidence which suggests increased summer aridity 5 recent improvements in chronological precision and data resolution point to an increase in aridity and decreased temperatures during the last glacial maximum 21 2 ka but suggest an increase in effective moisture during the immediately preceding interval of 24 27 ka 6 the mediterranean type climate is not exclusively a post 3 6 ma phenomenon but may have appeared intermittently during the course of the tertiary or before 7 if that is the case then the paradigm that the sclerophyllous evergreen habit represents a pre adaptation to summer drought may need re evaluation

hydrological conditions over the western mediterranean basin during the deposition of the cold sapropel 6 ca 175 kyr bp a new oxygen isotope record is reported from a stalagmite collected in the argentarola cave located on the tyrrhenian coast of italy as shown from observations and numerical modeling of n 18 o in modern precipitation the recorded n 18 o variability for this zone is dominated by the amount of precipitation so called amount effect the n 18 o profile measured in the stalagmite is characterized by a prominent negative excursion ca 2 3x between 180 and 170 kyr bp this paleoclimatic feature is interpreted as being due to a relatively wet period which occurred during the penultimate glacial period more precisely during marine isotope stage 6 5 this pluvial phase is shown to correspond chronologically to the deposition of the sapropel event 6 s6 although this particular sapropel event occurred during a cold phase the n 18 o excursion is similar to those corresponding to other sapropels s4 s3 and s2 the evidence for humid conditions during s6 in the western mediterranean basin agrees with previous studies based on deep sea sediment cores taken collectively the data suggest that during sapropel events dilution of ocean surface waters was not restricted to the output of the river nile but was rather widespread over the entire mediterranean sea due to increased rainfall 2002 elsevier science b v all rights reserved

extent and chronology of glaciations abstract the goal of the inqua commission on glaciation work group 5 extent and chronology of glaciations was to assemble glacial chronologies from around the world to better understand ice sheet volumes and extents at various times and to compile a gis supported database for past ice sheet extents the project involved the contribution of over 200 scientists working in more than 80 countries and territories throughout the world the resulting compilation represents the most complete survey of evidence of glaciation ever attempted the results are published in the form of three volumes europe north america and south america asia africa australia antarctica quaternary glaciations extent and chronology part i europe 2003a quaternary glaciations extent and chronology part ii north america 2003b quaternary glaciations extent and chronology part iii south america 2003c each of which contain a series of maps in digital format accompanied by an explanatory text which includes discussion of the type and quality of data used

global glacier dynamics during 100 ka pleistocene glacial cycles ice volume during the last ten 100 ka glacial cycles was driven by solar radiation flux in the northern hemisphere early minima in solar radiation combined with critical levels of atmospheric co 2 drove initial glacier expansion glacial cycles between marine isotope stage mis 24 and mis 13 whilst at 100 ka periodicity were irregular in amplitude and the shift to the largest amplitude 100 ka glacial cycles occurred after mis 16 mountain glaciers in the mid latitudes and asia reached their maximum extents early in glacial cycles then retreated as global climate became increasingly arid in contrast larger ice masses close to maritime moisture sources continued to build up and dominated global glacial maxima reflected in marine isotope and sea level records the effect of this pattern of glaciation on the state of the global atmosphere is evident in dust records from antarctic ice cores where pronounced double peaks in dust flux occur in all of the last eight glacial cycles glacier growth is strongly modulated by variations in solar radiation especially in glacial inceptions this external control accounts for 50 60 of ice volume change through glacial cycles internal global glacier climate dynamics account for the rest of the change which is controlled by the geographic distributions of glaciers

on the timing and mechanism of millennial scale climate variability during the last glacial cycle the demonstration that natural climate variability during the last glacial cycle shifted rapidly between remarkable extremes has dramatically revised the understanding of climate change to further advance our understanding research continues into the timings geographic distribution and nature of the millennial scale climate extremes and into the mechanisms for intra and inter hemispheric transmission of variability through the climate ocean system complementing the traditional definition of the timings of millennial scale climate variability from ice core 18o records we here further narrow down the temporal constraints by determining statistically significant anomalies in the major ion series of the gisp2 ice core this exercise offers an objective definition of the timing of climatic anomalies in northern hemisphere palaeoclimate proxy records of the last 110 000 years that significantly improves the potential for inter calibration of ice core tuned chronostratigraphies we then present a process oriented synthesis of proxy records from the northern hemisphere this leads to a conclusion that the dansgaard oeschger d o style fluctuations in these records are virtually in phase since all fall within a clear atmospheric pattern of concerted relative dominance shifts between polar westerly dominated winter type conditions and tropical monsoon dominated summer type conditions finally we speculate on a monsoon related mechanism that could help explain the anomalously long duration of d o interstadials 12 8 and 1 which coincided with cooling trends in antarctic records

multidisciplinary approach for palaeoclimatic signals of the non marine carbonates the case of the sarikavak tufa deposits afyon sw turkey abstract non marine carbonates such as travertine tufa and speleothem are quite sensitive for climatic fluctuations this study presents the new dating and the first pollen records from afyon sarikavak tufas sw turkey together with lithofacies descriptions geochemical and petrographic results obtained from drilling cores sl 2 sl 6 and sl 7 the data extensively provides insight into palaeoenvironmental and palaeoclimatic changes during the middle late pleistocene period according to core samples these fluvial tufa occurrences formed in high gradient and stepped fluvial conditions have been defined as barrage dammed and terraced slope systems in the investigated area the depositional lithofacies are moss tufa included macrophytes bryophytes and vertical stems phytoclastic tufa peloidal tufa micritic tufa microbial tufa intraclastic tufa extra formational tufa lime muddy clay and paleosol level in respectively the new u th radiometric dating and stable isotopes are evaluated together with previously published results in regard to new radiometric data tufa deposits occurred predominantly during the marine isotopic stages at 313 3 21 mis 9 295 8 63 mis 8 9 230 8 42 mis 7d e 228 8 12 mis 7d 215 7 17 mis 7c and 188 2 16 mis 6 7a ka respectively the climatic changes occurring between glacial and interglacial periods such as during the middle late pleistocene might probably influenced the precipitation of tufas in the area in addition the less negative and the more positive carbon isotopic values between 0 8 and 1 3 v pdb could be related to the progressive downstream co2 degassing from host rocks enhanced by high velocity current conditions changes in the soil co2 contribution and photosynthesis the changes of 18o values between 8 3 and 10 1 v pdb are most probably related to variable effects of evaporation in depositional environment palynofloral data gives important clues about the paleovegetation and paleoclimate of the region this field survey has been conducted the first time in this area both carbon values and palynological findings show that drought conditions were dominantly present in the pleistocene period but in some processes drought conditions decreased depending on the amount of rainfall the increasing amount of gymnosperm pollens is more likely to appear in more humid conditions due to the decreasing of drought condition in this time interval

palynology after y2k understanding the source area of pollen in sediments pollen grains preserved in lake and bog sediment provide a record of past vegetation that has been an important source of information about climate and land cover during the quaternary period yet from the beginning questions have been raised about the source area of pollen in sediment interpretation has been hampered by the lack of well developed theory treating the relationship between the spatial distribution of trees on the landscape and the percentages of pollen in sediment within the past decade however new theory models and empirical data show how heterogeneous vegetation is represented by pollen the distinction between local and regional pollen is explained by the prentice sugita dispersal deposition models which predict how the ratio of regional to local pollen changes with lake size sugita s model simulating a landscape with heterogeneous vegetation predicts the size of the relevant source area the area of vegetation reflected in between lake variations in pollen loading while demo

the glacial history of the dinaric alps montenegro abstract large areas of montenegro were glaciated during the pleistocene this paper presents evidence from the massifs of central montenegro including durmitor and sinjajevina moracke planine maganik prekornica and vojnik glacial deposits have been subdivided on the basis of morphostratigraphy and soil weathering and 31 u series ages from cemented tills provided a geochronological framework the largest glaciation occurred before 350 ka when a series of conjoined ice caps over the massifs of central montenegro covered a total area of nearly 1500 km 2 these formed during mis 12 and correspond with the largest skamnellian stage glaciations in greece to the south later middle pleistocene glaciations occurred during the penultimate glacial cycle correlating with the vlasian stage in greece mis 6 when ice caps covered an area of 720 km 2 over central montenegro there is also geochronological evidence of glacial deposits dating from the interval between mis 12 and mis 6 before the interglacial complex of mis 7 this glaciation appears to have been very similar in extent to that which occurred during mis 6 the last glacial cycle in central montenegro was characterised by valley and cirque glaciers covering a total area of 49 km 2 it is very likely that glaciers have been present in the mountains of central montenegro during every glacial cycle since a small glacier still survives today the smaller glaciers of the last glacial cycle are likely to have been associated with summer temperatures that were warmer than those of earlier cold stages the striking contrast in the extent and thickness of ice cover during the cold stages of the pleistocene has an important bearing on the geomorphological and biological evolution of the balkans

millennial scale oceanic climate variability off the western iberian margin during the last two glacial periods high resolution palaeoclimate records recovered from the iberian margin in core md95 2040 exhibit large fluctuations in oceanographic conditions over the last 190 ka large scale cooling of the surface ocean is indicated by the presence of the polar planktonic foraminifer neogloboquadrina pachyderma sinistral and in some instances the occurrence of ice rafted debris ird ice rafting episodes were prevalent in both of the last two glacials with greater intensity in stages 2 through 4 than in stage 6 the six youngest heinrich events are well defined during the last glacial but detrital carbonate is absent from heinrich layers hl6 hl5 and hl3 dansgaard oeschger stadial equivalent sub millennial ird deposition events have been detected in particular during stage 3 allowing a good match with the cooling displayed in the greenland ice core gisp2 sea surface temperature off portugal in stage 6 was in general warmer than during the last glacial pointing towards a weaker southward influence of polar water masses ice rafting occurred mainly in mid mis marine isotope stage 6 between 173 and 153 kyr as a group of poorly differentiated short duration quasi continuous events mainly marked by the high abundance of sinistral n pachyderma differences exist in ird composition relative to the last glacial with a reduced canadian derived detrital carbonate component combined with an important contribution of volcanic particles the lower magnitude and higher frequency of these events suggest that the higher temperatures would have induced iceberg waning closer to the source areas

the extent and chronology of cenozoic global glaciation abstract the quaternary is synonymous with extensive glaciation of earth s mid and high latitudes although there were local precursors significant glaciation began in the latest eocene ca 35 ma in eastern antarctica it was followed by glaciation in mountain areas through the miocene in alaska greenland iceland and patagonia later in the pliocene e g in the bolivian andes and possibly in tasmania and in the earliest pleistocene e g in the alps new zealand iceland and greenland today evidence from both the land and the ocean floors demonstrates that the major continental glaciations outside the polar regions rather than occurring throughout the 2 6 ma of the quaternary were markedly restricted to the last 1 ma 800 ka or less marine isotope stage mis 22 ca 870 880 ka included the first of the major worldwide events with substantial ice volumes that typify the later pleistocene glaciations i e mis 16 12 10 6 4 2

the last and penultimate glaciation in the north alpine foreland new stratigraphical and chronological data from the salzach glacier abstract the northern alpine foreland was repeatedly covered by massive piedmont glaciers during quaternary glacial maxima the salzach palaeoglacier lobe austria germany was the easternmost of a series of pleistocene piedmont glaciers entering the foreland through major alpine valleys it covered an area of more than 1000 km2 during at least four glacial maxima here we aim to bring more light into its history by analyzing multiple drill log data two major outcrops topographic data and absolute chronologies of sediments stratigraphic and lithofacies investigations are focused on proximal i e near the lobe axis and distal i e near terminal moraine deposits of the salzach glacier lobe the glacial carving into the miocene bedrock occurred during early glacial maxima and was rather uniform across the lobe with larger values only in the proximal parts of the glacier more than 100 m of accumulated sediments during later glacial maxima indicate a change in ice sheet dynamics and a characteristic sequence development which varies from proximal to distal lobe positions new luminescence ages suggest a depositional focus at the penultimate glacial period while the impact of the lgm was rather minor sediments of gravelly braided rivers dominate the proximal parts of the former lobe where meltwater discharge was generally high while sheetflood deposits dominate the distal near terminal lobe positions

constraint on the penultimate glacial maximum northern hemisphere ice topography 140 kyrs bp abstract the penultimate glacial maximum pgm 140 kyrs bp is known to be the most extensive glaciation on record that occurred during the last 400 kyrs over eurasia we used a coupled atmosphere ocean sea ice land model to simulate the climate of the pgm accounting for a reconstruction of the large pgm eurasian ice sheet due to uncertainties in the pgm laurentide ice sheet topography two simulations with different ice sheet topographies over north america large as for the last glacial maximum lgm and small as for 13 kyrs bp are performed results show that the simulated pgm glacial maximum climates are of comparable magnitude with previous simulations of the lgm in both cases assuming a small laurentide ice sheet instead of the lgm one in our pgm simulations results in a shift in the planetary waves this causes an increase in storm track activity over the north atlantic as well as higher temperatures and precipitation rates over north america north atlantic and over the eurasian ice sheet in addition it induces a negative temperature anomaly over east siberia yielding a thick snow cover which seems to be in agreement with data from recent arctic campaigns suggesting that an ice cap developed over beringia during the pgm all together the changes in large scale circulation and regional climate simulated using a small laurentide ice sheet match the proxies well based on our findings we suggest that the laurentide ice sheet might have been smaller during the pgm than during the lgm in turn also implying a larger eurasian ice sheet than during the lgm which is supported by various geological evidence of the pgm

vegetation history of the marine isotope stage 7 interglacial complex at ioannina nw greece abstract a new pollen record of the penultimate interglacial complex corresponding approximately to marine isotope stage mis 7 ca 186 000 245 000 years before present has been generated in core i 284 from the ioannina basin in northwest greece it represents the highest resolution terrestrial record for this interval available to date with a mean sampling interval of 200 years the sequence records four forested intervals correlated with mis 7e 7c 7a and a sub orbital scale event following 7a but within mis 7 the longest and most complete warm stage in terms of vegetational succession is mis 7c while the succession in mis 7e appears to be truncated by a shift to colder drier climatic conditions the results of biomisation suggest that during all of these intervals winter temperatures in nw greece remained lower than during the eemian or holocene while smaller populations of sclerophyllous taxa indicate that summers may have been wetter intervening intervals of open vegetation are correlated with mis 7d 7b and an oscillation following 7a low tree pollen percentages during mis 7d are interpreted as reflecting very cold and dry conditions concomitant with a period of low northern hemisphere insolation which resulted from a rare combination of minimum obliquity and maximum precession higher tree pollen percentages throughout mis 7b by contrast are indicative of relatively mild conditions in agreement with marine temperature and ice volume records sub orbital scale oscillations in tree population extent are also recorded in the new i 284 record suggesting that just as in the last climatic cycle nw greece was affected by rapid climatic oscillations that are associated with changes in the north atlantic