methodology of the last climatic cycle reconstruction in france from pollen data abstract a numerical method has been devised to reconstruct the climate of the last climatic cycle from pollen data reliable annual reconstructions have been published recently for the two french long sequences of la grande pile and les echets covering the last 140 millennia this paper gives more details on the method used it proposes new reconstructions based on an extended modern pollen data base these reconstructions are consistent with the previous ones especially detailed information is obtained on the seasonal characteristics of climate computations of gcm on the climate variations from 125 kyr to 115 kyr b p are confirmed for western europe the insolation variations have induced at that time a decrease of seasonality accompanied by an increased cyclonic activity in winter this has been the beginning of the first ice growth after the last interglacial other glacier growth phases are detected at the end of substage 5c and particularly at the end of substage 5a

late glacial climatic changes in eastern france lake lautrey from pollen lake levels and chironomids high temporal resolution analyses of pollen chironomid and lake level records from lake lautrey provide multi proxy quantitative estimates of climatic change during the late glacial period in eastern france past temperature and moisture parameters were estimated using modern analogues and plant functional types transfer function methods for three pollen records obtained from different localities within the paleolake basin the comparison of these methods shows that they provide generally similar climate signals with the exception of the bolling comparison of pollen and chironomid based temperature of the warmest month reconstructions generally agree except during the bolling major abrupt changes associated with the oldest dryas bolling allerod younger dryas and the younger dryas preboreal transitions were quantified as well as other minor fluctuations related to the cold events e g preboreal oscillation the temperature of the warmest month increased by not vert similar5 c at the start of bolling and by 1 5 3 c at the onset of the holocene while it fell by ca 3 to 4 c at the beginning of younger dryas the comparative analysis of the results based on the three lautrey cores have highlighted significant differences in the climate reconstructions related to the location of each core underlining the caution that is needed when studying single cores not taken from deepest part of lake basins

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

younger dryas style cooling events at glacial terminations i vi at odp site 658 associated benthic δ13c anomalies constrain meltwater hypothesis high resolution planktonic and epibenthic stable isotope records from ocean drilling program site 658 off northwest africa provide a basis for a detailed study of glacial terminations i vi during the last 650 000 years the duration of the terminations was about one half to one quarter of an orbital precession cycle 5800 10 700 years when its amplitude was high at low amplitudes the terminations lasted longer than half an obliquity cycle 29 000 years marked climatic rebounds similar to the younger dryas each with a duration of 1000 2500 years subdivided all six terminations into distinct steps a b and c important parts of the deglacial steps were as brief as 700 1000 years the speed of climatic change suggests that special associations existed between orbital forcing and inherent instability of the ice sheets in harmony with published models the more rapid pulses of glacial meltwater incursions to the northern north atlantic led to one or more brief short term shut downs of north atlantic deep water formation this process is reflected by pronounced benthic 13c minima that precisely coincide in most cases with the end of the 18o deglaciation steps and immediately terminate with succeeding younger dryas style cooling events thus we conclude that the rebounds resulted from a short term antecedent estuarine circulation regime in the north atlantic except for the younger dryas itself which succeeded the allerod with its well ventilated atlantic deepwater circulation and hence continues to be an enigma

climatic transfer function from quaternary molluscs in european loess deposits abstract correspondence and multiple regression analysis of terrestrial molluscs in the loess sections of achenheim alsace france has permitted the reconstruction of climatic variations during the last three glacial interglacial cycles back to 339 000 yr b p the sequence has been dated according to the specmap chronology of imbrie et al 1984 and the fossil faunas have been calibrated in relation to recent assemblages sampled in defined ecological conditions in sweden and france transfer functions that relate the abundances of different species to climate allow the reconstruction of temperature and precipitation estimates for the coldest february and warmest august months in present day alsace were obtained and variations in temperature between 13 and 2 c in winter and 10 and 17 c in summer were determined these results are consistent with those yielded by transfer functions using other continental fossils estimates differ for past precipitation summer precipitation is always less than present with values between 50 and 78 mm while modern august values are 76 mm higher winter estimates are always higher than the present mean between 76 and 33 mm while the recent february value is 34 mm comparisons between cycles show that the climatic patterns described for one cycle cannot be strictly applied to the others comparisons have been made with the pollen stratigraphy of la grande pile the nearest quantified sequence to achenheim and with some atlantic cores in order to study the magnitude of deviations from modern mean values of the climatic parameters

the hierarchical structure of glacial climatic oscillations interactions between ice sheet dynamics and climate abrupt climatic oscillations around the north atlantic have been identified recently in greenland ice cores as well as in north atlantic marine sediment cores the good correlation between the dansgaard oeschger events in the ice and the heinrich events in the ocean suggests that climate in the north atlantic region underwent several massive reorganizations in the last glacial period a characteristic feature of these events seems to be their hierarchical structure every 7 to 10 thousand years when the temperature is close to its minimum the ice sheet undergoes a massive iceberg discharge this heinrich event is then followed by an abrupt warming then by several other oscillations each one lasting between one and two thousand years these secondary oscillations do not have a clear signature in marine sediments but constitute most of the dansgaard oeschger events found in the ice here we use a simplified model coupling an ice sheet and an ocean basin in order to illustrate how the interactions between these two components can lead to such a hierarchical structure the ice sheet model exhibits internal oscillations composed of ice sheet growing phases and basal ice melting phases that induce massive iceberg discharges these massive fresh water inputs in the ocean stop for a moment the thermohaline circulation enhancing the temperature contrast between low and high latitudes just after this event the thermohaline circulation restarts and an abrupt warming of high latitude regions is observed for some parameter values these warmer temperatures have in turn some influence on the ice sheet inducing secondary oscillations similar to those found in paleoclimatic records although the mechanism presented here may be too grossly simplified it nevertheless underlines the potential importance of the coupling between ice sheet dynamics and oceanic thermohaline circulation on the structure of the climatic records during the last glacial period

origin and consequences of cyclic ice rafting in the northeast atlantic ocean during the past 130 000 years deep sea sediment cores recovered from the northeast atlantic ocean were examined in order to elucidate the influence of the earth s orbital parameters on major ice rafting analyses of coarse grained ice rafted debris and planktonic foraminifers revealed a strong reaction to the precession signal since 130 000 yr b p dropstone layers have been deposited each half period of a precessional cycle 11 000 1000 yr ice rafting occurs during times of winter minimum summer maximum insolation and summer minimum winter maximum insolation in the first case high summer insolation forces meltwater discharge from the ice sheets into the polar seas which subsequently enhances formation of sea ice during the winter in the second case growth of continental ice enhances iceberg production which also leads to a salinity reduction of surface seawater both situations result in a southward penetration of polar water thus the marine record of dropstones documents ice rafting not only during weichselian stades but also during cold events within interstades the regularity of ice rafting yields a useful framework to calibrate and elucidate climatic changes not only in the region of the north atlantic ocean but also in remote areas such as the pacific ocean and the antarctic

the holocene and upper pleistocene pollen record from padul granada spain a new study two borings were made at the site of padul granada pollen analysis of 200 spectra from two successive sequences 14 8 and 8 m deep enables a description of the vegetational and climatic history of this region the most southern one in europe from early wurmian times the chronology is supported by twenty one 14c dates original equivalents are found for the great european prewurm interstadials a markedly arid though thermically not extreme episode exactly equivalent to stage 4 of the marine isotopic stratigraphy closes this relatively temperate period the middle part of the last glacial shows climatic fluctuations that are poorly characterized as is often the case in europe for this period a long section very probably corresponding to the complete last pleniglacial does not show any climatic amelioration towards 15 000 yr b p a change in the diagram is noted that can only be interpreted as reflecting a larger expansion of a regional steppe cover this event also reported on three occasions in southeast france marks the beginning of the oldest dryas the climatic amelioration of ca 13 000 yr b p is far more pronounced here than anywhere else in europe whereas that at 10 000 yr b p is not so clearly marked this unexpected result may be accounted for by the fact that padul is the first continental site so far south and so near pleniglacial refuges to be known on the other hand this result is consistent with what is known from oceanic isotopic stratigraphy a quite new late glacial and holocene vegetational history is revealed characterized by the early appearance and dominance of quercus ilex oak forests of a southern type and the early occurrence of quercus suber and olea it is the first account of a complete history of the postglacial reafforestation in a region with a modern semi arid mediterranean climate from the palaeoclimatic point of view it shows that the hot and humid holocene optimum was attained slightly before 8000 yr b p and that the holocene climatic fluctuations were of but small amplitude

pollen based continental climate reconstructions at 6 and 21 ka a global synthesis subfossil pollen and plant macrofossil data derived from 14c dated sediment profiles can provide quantitative information on glacial and interglacial climates the data allow climate variables related to growing season warmth winter cold and plant available moisture to be reconstructed continental scale reconstructions have been made for the mid holocene mh around 6 ka and last glacial maximum lgm around 21 ka allowing comparison with palaeoclimate simulations currently being carried out as part of the fifth assessment report ar5 of the intergovernmental panel on climate change the synthesis of the available mh and lgm climate reconstructions and their uncertainties obtained using modern analogue regression and model inversion techniques is presented for four temperature variables and two moisture variables reconstructions of the same variables based on surface pollen assemblages are shown to be accurate and unbiased reconstructed lgm and mh climate anomaly patterns are coherent consistent between variables and robust with respect to the choice of technique they support a conceptual model of the controls of late quaternary climate change whereby the first order effects of orbital variations and greenhouse forcing on the seasonal cycle of temperature are predictably modified by responses of the atmospheric circulation and surface energy balance

was there an abrupt cold climatic event in the middle eemian pollen record from a palaeolake at the hieronimowo site ne poland abstract seventy samples of lacustrine sediments from a palaeolake at the hieronimowo site ne poland were investigated by pollen analysis method the obtained results indicate that the examined sequence spans the whole eemian interglacial mis 5e the beginning of the early vistulian weichselian mis 5d and some undefined period of the plenivistulian middle weichselian mis 2 4 the specific feature of the studied profile is the great thickness of deposits representing the hornbeam phase of the eemian interglacial e5 r paz which was the younger part of the climatic optimum of this interglacial and the very well developed pollen record of this phase that is absent in other profiles in ne poland due to this our study allowed for the first time in ne poland the detailed reconstruction of changes in the vegetation and in the mean january and july temperature during the middle part of the eemian interglacial this reconstruction unequivocally rules out the existence of an abrupt short lasting cold event at that time only a gradual slight increase in temperature was apparent during the older part of the hornbeam phase to 21 c for july and to 0 c for january and gradual decrease during its younger part to 17 c for july and to 5 c and

predicting reach specific properties of fluvial terraces to guide future fieldwork a case study for the late quaternary river allier france with the fluver2 model numerical models have not yet systematically been used to predict properties of fluvial terrace records in order to guide fieldwork and sampling this paper explores the potential of the longitudinal profile model fluver2 to predict testable field properties of the relatively well studied late quaternary allier system in france for the allier terraces an overlapping 14c and u series chronology as well as a record of 10be erosion rates exist the fluver2 modelling exercise is focused on the last 50 ka of the upper allier reach because for this location and period the constraints of the available dating techniques are tightest a systematic calibration based on terrace occurrence and thicknesses was done using three internal parameters related to 1 the sediment erodibility 2 the sediment transport distance and 3 the sediment supply derived from the surrounding landscape as external model inputs the best available reconstructed tectonic climatic and base level data were used calibrated model outputs demonstrate a plausible match with the existing fluvial record validation of model output was done by comparing the modelled and measured timing of aggradation and incision phases for the three locations the modelled range of landscape erosion rates showed a reasonably good match with existing erosion rate estimates derived from 10be measurements of fluvial sands the quasi validated model simulation was subsequently used to make new testable predictions about the timing and location of aggradation and erosion phases for three locations along the allier river the validated simulations predict that along the allier reach specific dynamics of incision and aggradation related to the variations in sediment supply by major tributaries cause relevant differences in the local fluvial terrace stratigraphy numerical models have not yet systematically been used to predict properties of fluvial terrace records in order to guide fieldwork and sampling this paper explores the potential of the longitudinal profile model fluver2 to predict testable field properties of the relatively well studied late quaternary allier system in france for the allier terraces an overlapping 14 c and u series chronology as well as a record of 10 be erosion rates exist the fluver2 modelling exercise is focused on the last 50 ka of the upper allier reach because for this location and period the constraints of the available dating techniques are tightest a systematic calibration based on terrace occurrence and thicknesses was done using three internal parameters related to 1 the sediment erodibility 2 the sediment transport distance and 3 the sediment supply derived from the surrounding landscape as external model inputs the best available reconstructed tectonic climatic and base level data were used calibrated model outputs demonstrate a plausible match with the existing fluvial record validation of model output was done by comparing the modelled and measured timing of aggradation and incision phases for the three locations the modelled range of landscape erosion rates showed a reasonably good match with existing erosion rate estimates derived from 10 be measurements of fluvial sands the quasi validated model simulation was subsequently used to make new testable predictions about the timing and location of aggradation and erosion phases for three locations along the allier river the validated simulations predict that along the allier reach specific dynamics of incision and aggradation related to the variations in sediment supply by major tributaries cause relevant differences in the local fluvial terrace stratigraphy copyright 2016 john wiley sons ltd

clumped isotope paleotemperatures from mis 5 soil carbonates in southern hungary abstract quantitative paleotemperature reconstructions for the continents including east central europe over marine isotope stage 5 mis 5 and specifically the last interglacial lig mis 5e are scarce and mostly based on pollen assemblages here we provide soil and air temperature reconstructions for the summer season of mis 5e 5c using carbonate clumped isotope thermometry applied to soil carbonate concretions in the dunaszekcs loess paleosol record southern hungary the sediments making up the s1 pedocomplex investigated represent the mis 5 as demonstrated by bracketing k feldspar post ir irsl225 290 ages of 63 to 164 ka both the absolute ages and pedogenic susceptibility p curve indicate that all the subtages of mis 5 were found to be recorded in the sequence and soil carbonates found 1 m depth below the paleosurface of the s1 soil provide pristine undisturbed isotopic signals the soil carbonate concretions likely formed during mis 5e at a relatively shallow 20 50 cm depth but a later formation during mis 5c at 50 cm depth is also plausible clumped isotope based soil temperatures st 47sc ranged from 16 to 20 c and reconstructed summer season air temperatures sats for the lig are consistently lower than the modern values at the site by 1 5 c matching surprisingly well the soil bacteria membrane lipid based mis 5e air temperature estimates from a nearby serbian site at the same time the reconstructed sat values do not match the 2 4 c positive warm season anomalies modeled for east central europe between lig and present day in paleoclimate simulations st uncertainties of 1 6 c infiltration driven cooling of soil temperatures and the possibility of mis 5c formation of the investigated carbonates may account for this proxy model data discrepancy oxygen isotope compositions of summer season paleo rainwaters for mis 5e 5c as reconstructed using the st 47sc and 18osc data of soil carbonates were found in a range of 6 7 and 6 4 matching the modern mean summer season value of 6 2 0 94 within error

antarctic sea ice and palaeoproductivity variation over the last 156 000 years in the indian sector of southern ocean abstract antarctic sea ice plays a vital role in global climate via its impact on ocean circulation biological productivity and co2 partitioning between the ocean and the atmosphere however very little is known about its past history especially in the southwestern indian sector of the southern ocean so we here provide new quantitative records of winter sea ice concentration wsic and duration wsid sea surface temperatures sst and productivity in sediment core sk 200 33 55 s 45 e from the permanently open ocean zone over the last 156 000 years the new records combined with regional records indicate that the hydrological structures migrated northward by a few degrees of latitude during all glacial periods with the southern antarctic circumpolar current front reaching the core site the antarctic polar front located at 46 s and the winter sea ice wsi probably extending to 49 s in contrast hydrological fronts and wsi edge migrated poleward by a couple of degrees of latitude during the early holocene and last interglacial comparison to sst and wsi records from different sectors of the so suggests higher amplitude variations in wsi in the atlantic sector as compared to the indian and western pacific sectors over the last glacial interglacial cycle which we attribute to the presence of the weddell gyre transporting far to the north the sea ice produced in the weddell sea the new records also suggest a drop in productivity in the pooz during glacial periods probably related to greater wsi extent and reduced growing season

reconstruction of the grande pile eemian using inverse modeling of biomes and δ13c abstract a new method to reconstruct past climatic conditions between 130 and 100 ka bp from pollen and isotopic data is applied to a previously unanalyzed grande pile core gpxxi we applied the inverse mode to the biome4 vegetation model the method utilizes 13 c measured in parallel to the pollen samples as a constraint for the model first the biomes and the 13 c simulated by the model are compared with the biome allocation of the pollen data the 13 c to be simulated takes into account the degradation effect on the preserved organic matter this procedure allows the reconstruction of the mean annual temperature and precipitation as well as the mean temperatures of the warmest and coldest months we show that during the eemian sensu stricto the reconstructed precipitation is similar to modern values with low variability the cold stadials and the penultimate glaciation are characterized by very low precipitation amounts the temperature estimates however indicate differences with several oscillations identified the peak values are reached at about 124 125 ka bp but two other warm intervals are also identified the variations in temperature appear to be related to sea surface temperature oscillations in the north atlantic region and are also in agreement with the timing of ice sheet build up in the northern hemisphere seasonal variations are also identified in the estimated temperatures of the warmest and coldest months

supra regional correlations of the most ancient paleosols and paleolithic layers of kostenki borschevo region russian plain abstract the archaeological site kostenki12 located on the middle don river provides a key stratigraphic profile for regional paleopedological paleoenvironmental geological and cultural sequences containing the oldest known cultural layers of the region layer v paleolithic layer iv upper paleolithic layer iii kostenki strelets culture early phase dating to the early part of mis3 or in chronometric terms to 54 42 ka kostenki12 complements kostenki14 markina gora which is a key profile for the interval 42 27 ka the new data from kostenki12 show that the east european upper paleolithic began 45 ka the stratigraphy exhibits similarities to that of borschevo5 the kostenki12 pollen diagram is correlated with 1 other pollen diagrams from kostenki borschevo region 2 the most detailed climatostratigraphical scale of the russian plain late pleistocene 3 16 o 18 o greenland gisp2 scale 4 13 c 14 c record from stalagmite at villars cave france as well as with pollen records 5 7 from 5 lake monticchio italy 6 southern black sea m72 5 25 gc1 and 7 glinde and moershoofd northern germany the results of the supra regional paleoenvironmental correlations demonstrate that the lowest paleolithic layer v and paleosol d characterized by elm dominance correlate to the second half of the optimum of the glinde interstadial at 51 48 ka corresponding to do 14 the earliest upper paleolithic layer iv and paleosol b characterized by coexistence of elm forests and wet meadows began to form during the second part of the moershoofd interstadial optimum at 46 44 ka correlating with do 12 paleosol a and layer iii kostenki strelets culture began to form after the abrupt end of the moershoofd interstadial 43 5 ka during unstable conditions according to pollen and paleozoological data steppe with horse dominance and later spruce forest tundra with reindeer dominance in paleozoological complex these correlations provide more accurate dating of the paleolithic layers and paleosols at kostenki borschevo suggesting that previously reported radiocarbon dates on units below ci tephra layer are too young but that the osl chronology is generally accurate

oxygen isotopic composition of the mediterranean sea since the last glacial maximum constraints from pore water analyses abstract interstitial waters recovered from ocean drilling program leg 161 site 976 in the western mediterranean sea are used in conjunction with a numerical model to constrain the 18o of seawater in the basin since the last glacial maximum including sapropel event 1 to resolve the oxygen isotopic composition of the deep mediterranean we use a model that couples fluid diffusion with advective transport thus producing a profile of seawater 18o variability that is unaffected by glacial interglacial variations in marine temperature comparing our reconstructed seawater 18o to recent determinations of 1 0 for the mean ocean change in glacial interglacial 18o due to the expansion of global ice volume we calculate an additional 0 2 increase in mediterranean 18o caused by local evaporative enrichment this estimate of 18o change due to salinity variability is smaller than previous studies have proposed and demonstrates that mediterranean records of foraminiferal calcite 18o from the last glacial period include a strong temperature component paleotemperatures determined in combination with a stacked record of foraminiferal calcite depict almost 9 c of regional cooling for the last glacial maximum model results suggest a decrease of 1 1 in seawater 18o relative to the modern value caused by increased freshwater input and reduced salinity accompanying the formation of the most recent sapropel the results additionally indicate the existence of isotopically light water circulating down to bottom water depths at least in the western mediterranean supporting the existence of an anti estuarine thermohaline circulation pattern during sapropel event 1

timing and dynamics of the last deglaciation from european and north african δ13c stalagmite profiles comparison with chinese and south hemisphere stalagmites abstract the last deglaciation and its climatic events such as the bolling allerod ba and the younger dryas yd have been clearly recorded in the 13 c profiles of three stalagmites from caves from southern france to northern tunisia the three 13 c records dated by thermal ionization mass spectrometric uranium thorium method tims show great synchroneity and similarity in shape with the chinese cave 18 o records and with the marine tropical records leading to the hypothesis of an in phase between 15 5 and 16 ka 0 5 ka postglacial warming in the northern hemisphere up to at least 45 n the ba transition appears more gradual in the speleothem records than in the greenland records and the allerod seems warmer than the bolling showing here close similarities with other marine and continental archives a north south gradient is observed in the ba trend it cools in greenland and warms in our speleothem records several climatic events are clearly recognizable a cooler period at about 14 ka older dryas od the intra allerod cold period at about 13 3 ka the yd cooling onset between 12 7 and 12 9 0 3 ka similar to the ba the yd displays a gradual climate amelioration just after its onset at 12 75 0 25 ka up to the preboreal and is punctuated by a short climatic event at 12 15 ka even though the southern hemisphere stalagmite records seem to indicate that the postglacial warming started about 3 ka 1 8 ka earlier in new zealand 41 s and about 1 to 2 ka earlier in south africa 24 1 s large age uncertainties essentially due to slow growth rates make the comparison still perilous the overall 13 c speleothem record seems to follow a baseline temperature increase controlled by the increase in insolation and punctuated by cold events possibly due to the n america freshwater lake discharges

the mutual climatic range method of palaeoclimate reconstruction based on insect fossils new applications and interhemispheric comparisons abstract the mutual climatic range mcr method of palaeoclimate reconstruction has been employed in europe for the last decade a quantitative calibrated method mcr has many advantages over qualitative methods more recent applications deal with eastern and central north america and the method is also being developed for desert and arctic faunas the climate envelopes for north american beetles have been compiled using a 25 km gridded north american climate database that pairs climate parameters with modern collection sites modern tests of the reliability of the mcr method for north american species yielded similar results to prior european tests linear regressions of predicted on observed values yielded equations used to calibrate the mcr estimates work is under way to develop mcr estimates of mean annual precipitation for fossil assemblages from the desert southwest where moisture conditions may play a more important role in determining beetle species ranges an examination of british and north american mean july temperature reconstructions during the late wisconsinan glacial interval compares and contrasts three sets of records the north american records show no indication of the younger dryas cooling that is clearly marked in records from northwest europe the mcr method adds vigour to our reconstructions and allows us to compare between regions and with other palaeoenvironmental methods

speleothem evidence of warm episodes in northeast france during marine oxygen isotope stage 3 and implications for permafrost distribution in northern europe u th ages have been obtained by tims on the growth periods of a stalagmite from the grotte des puits de pierre la treiche northeastern france during the middle part of the weichselian glaciation marine isotope stage 3 between 55 36 0 95 and 53 34 0 49 ka and around 45 85 0 49 ka these episodes are contemporaneous with abrupt climatic variations recorded in greenland ice cores greenland interstadials 12 14 and 15 that have been previously recognized in european speleothems they also coincide with two interstadials known as goulotte and pile in the grande pile pollen sequence eastern france which have been correlated with the moershoofd complex in the netherlands such evidence of speleothem deposition related to temperate episodes gives a strong indication of the absence of continuous shallow permafrost during the middle part of mis 3 in northeastern france

correlation of the eemian and the weichselian with deep sea oxygen isotope stratigraphy abstract the eemian interglacial was defined in the netherlands and is correlated all over northern europe it is now demonstrated that the eemian was the last interglacial in europe thus it is obvious that it should correlate with either the entire stage 5 in the deep sea oxygen isotope stratigraphy or with parts of stage 5 several observations prove that the eemian correlates with substage 5e the two other peaks in stage 5 correlates with the warm interstadials brorup and odderade in northern europe

abrupt cold spells in the northwest mediterranean hitherto unknown abundance peaks of left coiling l c neogloboquadrina pachyderma from a gulf of lions piston core indicate that abrupt cold spells associated with atlantic heinrich events affected the mediterranean n pachyderma l c is typical of sub polar waters in the open ocean the southern edge of its glacial north atlantic bioprovince reached south portugal only trace abundances of n pachyderma l c are known from quaternary mediterranean sediments suggesting that no significant invasions occured via the strait of gibraltar the gulf of lions abundance peaks therefore seem to reflect area specific thriving of a normally rare but indigenous taxon in the western mediterranean through local favorable habitat development the general planktonic foraminiferal record suggests that the basic hydrographic regime in the gulf of lions with wintertime deep convective overturn was relatively stable over the past 60 kyr under these conditions high abundances of n pachyderma l c would essentially imply temperature reductions of the order of 5 8 relative to the present

the last climatic cycles in western europe a comparison between long continuous lacustrine sequences from france and other terrestrial records abstract during the last two decades numerous studies applied to various continental deposits have highly improved the knowledge of environmental changes in western europe during the last climatic cycles here we review a set of available data and try to correlate and compare the three long lacustrine sequences from france la grande pile les echets and le velay with other west european discontinuous limnic deposits fluvial systems and l ss accumulations limnic sequences provide the best records of the last interglacial and early glacial ca 125 75 kyr allowing a clear picture of environmental changes during this interval nevertheless there are divergent interpretations on the timing and climate regime of the last interglacial during the last glacial in the north atlantic deep sea cores and greenland ice cores short term abrupt climatic fluctuations bond events dansgaard oeschger events which are poorly or partly reflected on the continent have been recognised the classical subdivision in a lower ca 75 55 kyr very cold middle ca 55 29 kyr cold and upper pleniglacial ca 29 15 kyr very cold is confirmed both by limnic and terrestrial sequences in the rhine valley north eastern france belgium and the netherlands subcontinuous l ss accumulation river systems and associated periglacial features provide quantitative climate reconstructions that are compared with those obtained from limnic sequences interstadial events may be correlated with the major warm oscillations of the grip core during the upper pleniglacial no clear vegetation changes are apparent from lacustrine pollen sequences whereas thick l ss accumulations have registered a succession of climatic changes the timing of the lateglacial warming is now well documented from rare annually laminated lake sediments

a late pleistocene long pollen record from lake urmia nw iran abstract a palynological study based on two 100 m long cores from lake urmia in northwestern iran provides a vegetation record spanning 200 ka the longest pollen record for the continental interior of the near east during both penultimate and last glaciations a steppe of artemisia and poaceae dominated the upland vegetation with a high proportion of chenopodiaceae in both upland and lowland saline ecosystems while juniperus and deciduous quercus trees were extremely rare and restricted to some refugia hippophae rhamnoides constituted an important phanerophyte particularly during the late last glacial period a pronounced expansion in ephedra shrub steppe occurred at the end of the penultimate late glacial period but was followed by extreme aridity that favoured an artemisia steppe very high lake levels registered by both pollen and sedimentary markers occurred during the middle of the last glaciation and late part of the penultimate glaciation the late glacial to early holocene transition is represented by a succession of hippophae ephedra betula pistacia and finally juniperus and quercus the last interglacial period eemian slightly warmer and moister than the holocene was followed by two interstadial phases similar in pattern to those recorded in the marine isotope record and southern european pollen sequences

climatic interpretation of terrestrial malacofaunas of the last interglacial in southeastern france abstract the sequence of the ruisseau de l amourette in the french alps covering the isotope stages 5e 5d 5c and part of 5a and 6 was studied for terrestrial mollusks correspondence analysis of the mollusk assemblages permits reconstruction of temperature and moisture trends using knowledge of the modern ecology of the recognized species the classic environmental succession of the last interglacial early glacial wurmian is recognized the eemian sub stage 5e suggests warm and moist conditions it is followed by the cold melisey i sub stage 5d showing moisture variation from dry in the lower part to moist in the upper part the mollusk equivalent of st germain i and ii also indicates warm and moist conditions the melisey ii stadial sub stage 5b is missing but may be reflected by the deposition of barren gravel layers all these environmental oscillations agree with the fluctuations described in the literature however stage 5e indicates a particular trend as the mollusks recorded two well individual cool events which seem to correspond to variations identified in various west european continental records however as no particular cold indicator species were identified these events cannot be related to strong climatic fluctuations as emphasized in the early studies of the greenland grip ice core or in north atlantic and western european records

lateglacial and early flandrian coleoptera from la taphanel massif central france climatic and ecological implications a lateglacial and early holocene sequence of coleopteran assemblages is described from la taphanel in the massif central france the site is a sediment filled small lake at an altitude of almost 1000 m the insect fauna provides evidence for a detailed palaeoecological reconstruction and in particular enables a reconstruction of climatic changes at the close of the last glaciation a sudden climatic warming occurs at about 13000 yr bp followed by a temperate episode equivalent in time to the bolling period there is clear evidence of a short cold period between the bolling and allerod that is approximately equivalent to the older dryas period the allerod phase is decidedly cooler than the bolling as is shown by the coleoptera from several sites in northwest europe a clear younger dryas signal is provided by the coleoptera with climates similar in severity to those of the glacial period the climatic improvement at the start of the holocene is also sudden so that by preboreal times temperatures were equivalent to those of the present day

late devensian and holocene palaeoecology and palaeoenvironments of the morrone birkwoods aberdeenshire scotland results are presented from analyses of pollen vascular plant macrofossils and bryophyte remains at the morrone birkwoods a site in the eastern highlands of scotland the sedimentary record spans the past ca 12 500 yr and is dated by a series of radiocarbon determinations quantitative palaeoclimate reconstructions are made using pollen climate response surfaces with the selection of analogues constrained using evidence from the macrofossil stratigraphy the results generally are in remarkably close agreement with those reconstructed from beetle remains by atkinson et al the only significant discrepancy is with respect to the extent of the warming at ca 12500 yr bp the palaeoclimate record indicates a marked cooling that coincides in age with the older dryas event and which interrupts an overall cooling trend throughout the duration of the late glacial interstadial that culminates in the younger dryas there is also evidence of a climate fluctuation during the first 500 yr of the holocene the mid and late holocene record of palaeoclimate is in contrast remarkably invariant until the last ca 1500 yr during which there is evidence of a period of warming followed by a subsequent cooling it is speculated that these may correspond to the medieval warm period and to the little ice age respectively the morrone birkwoods are noted today for their sub arctic vegetation and their rich flora with the arctic alpine and northern montane biogeographical elements especially well represented the macrofossil record indicates that the flora has long had this general character whilst both this and the pollen record indicate that the sub arctic character of the vegetation has most likely persisted since earliest holocene times

holocene climatic change in morocco a quantitative reconstruction from pollen data annual precipitation july and january temperatures were reconstructed from a continuous holocene pollen sequence from the middle atlas morocco using the best modern analogues method the reconstructions show a clear difference between the early and late holocene from 10 ka to 6 5 ka the climate was drier and warmer than during the period since 6 5 ka the average value of annual precipitation was 870 mm until 6 5 ka then rose to 940 mm between 10 ka and 6 5 ka january and july temperatures were about 4 c higher than the present both temperatures show a marked decrease between 7 ka and 6 ka after 6 5 ka july and january temperatures fluctuated between 21 and 23 c and 2 5 and 5 c respectively january temperatures show a period of intermediate values 3 5 c between 4 ka and 5 5 ka the reconstructed climate values generally match palaeolimnological data from the same core which show five intervals of low lake level during the holocene they are also consistent with regional scale cohmap simulated palaeoclimate that shows contrasting patterns of rainfall variation between the northwesternmost part of africa and the intertropical band

pollen analysis of a long upper pleistocene continental sequence in a velay maar massif central france abstract a new 20 m sequence is presented which is based on 279 spectra derived from a coring at le bouchet lake massif central france the vegetational history of this region is described back to the end of the last interglacial ribains interglacial the two preglacial early glacial forested interstadials st geneys 1 and st geneys 2 are evidence for the first time in the massif central in spite of the altitude of the site 1200 m they suggest a quite temperate vegetation with the same mesophilous character as during the holocene the pleniglacial appears to be threefold with two cold episodes lower and upper pleniglacial divided by a long complex period of moderate climatic improvement the vegetation history of this mountain region is compared with that evidenced for the same period on the basis of the sequence of les echets at a lower altitude 267 m botanical and climatic inferences are discussed

meandering rivers in modern desert basins implications for channel planform controls and prevegetation rivers the influence of biotic processes in controlling the development of meandering channels in fluvial systems is controversial the majority of the depositional history of the earth s continents was devoid of significant biogeomorphic interactions particularly those between vegetation and sedimentation processes the prevailing perspective has been that prevegetation meandering channels rarely developed and that rivers with braided planforms dominated however recently acquired data demonstrate that meandering channel planforms are more widely preserved in prevegetation fluvial successions than previously thought understanding the role of prevailing fluvial dynamics in non and poorly vegetated environments must rely on actualistic models derived from presently active rivers developed in sedimentary basins subject to desert climate settings the sparsest vegetated regions experiencing active sedimentation on earth these systems have fluvial depositional settings that most closely resemble those present in prevegetation and extra terrestrial environments here we present an analysis based on satellite imagery which reveals that rivers with meandering channel planforms are common in modern sedimentary basins in desert settings morphometric analysis of meandering fluvial channel behaviour where vegetation is absent or highly restricted shows that modern sparsely and non vegetated meandering rivers occur across a range of slope gradients and basin settings and possess a broad range of channel and meander belt dimensions the importance of meandering rivers in modern desert settings suggests that their abundance is likely underestimated in the prevegetation rock record and models for recognition of their deposits need to be improved

rodent paleofaunas as indicators of climatic change in europe during the last 125 000 years abstract this paper presents a quantitative reconstruction of the european late pleistocene paleoclimate based on 72 rodent assemblages of five sequences from france germany and bulgaria covering the last interglacial glacial cycle they show a pattern of severe changes in temperature with reduced precipitation during the coldest periods a tentative correlation between the isotopic and palynological records and the paleotemperature changes is shown these changes are consistent with variations in atmospheric circulation patterns in response to an expanding retracting fennoscandian ice sheet they can be attributed to the enhancement weakening of the scandinavian polar anticyclone and its associated dry winds the south north shifting of the north atlantic polar front and the varying supply of moist air from the atlantic qualitative paleoenvironmental analysis shows broadleaved deciduous forests in france and bulgaria during most of the studied period taiga and tundra appeared in eastern france during the lower wurm the german sequence indicates the presence of coniferous forests these results are broadly consistent with other paleobiological records mammalian avian and insect faunas isotopic record in dental tissue palynology the main discrepancies with the paleoclimate inferred from the palynological record are found during the coldest periods and are probably due to the interaction between vegetation climate and atmospheric co2 levels

reconstruction of climate and vegetation changes of lake bayanchagan inner mongolia holocene variability of the east asian monsoon a high resolution pollen and pediastrum record spanning 12 500 yr is presented for lake bayanchagan 115 21 e 41 65 n and 1355 m a s l southern inner mongolia individual pollen taxa pt mat and the pft affinity scores pft mat were used for quantitative climatic reconstruction from pollen and algal data both techniques indicate that a cold and dry climate similar to that of today prevailed before 10 500 cal yr b p the wettest climate occurred between 10 500 and 6500 cal yr b p at which time annual precipitation was up to 30 60 higher than today the early holocene increases in temperature and precipitation occurred simultaneously but mid holocene cooling started at approximately 8000 cal yr b p 1500 yr earlier than the drying vegetation reconstruction was based on the objective assignment of pollen taxa to the plant functional type the results suggest that this region was dominated by steppe vegetation throughout the holocene except for the period 9200 to 6700 cal yr b p when forest patches were relatively common inner mongolia is situated at the limit of the present east asian monsoon and patterns of vegetation and climate changes in that region during the holocene probably reflect fluctuations in the monsoon s response to solar insolation variations the early to middle holocene monsoon undoubtedly extended to more northern latitudes than at present

calibration of the climatic signal in a new pollen sequence from la grande pile a new core gpxx from la grande pile vosges france has enabled a more precise evaluation of pollen data concerning the last climatic cycle at this site and has enabled reconstruction of the monthly temperature and precipitation this paper shows that the various components of the reconstructed climatic signal are clearly separated and that they are coherent with the vegetation dynamics the eemian interglacial was influenced first by an oceanic climate and second by a more continental one the two interstadials st germain i and ii were mainly continental these three temperate periods ended with a cool and humid transition period dominated by boreal forests which may have been favourable to ice accretion the dansgaard oeschger oscillations from 55 to 25 kyr bp are not significantly recorded in la grande pile

the climate in western europe during the last glacial interglacial cycle derived from pollen and insect remains using the pollen sequence of la grande pile xx france we review problems with the application of transfer functions in paleoclimatic reconstructions one of them is to find modern analogues for the herbaceous vegetation of the cold periods we propose a method to distinguish between steppes and tundra vegetations for which the moderns are only partial analogues of the glacial periods another method to solve these problems is based on constraining by insect remains the two methods provide coherent reconstructions the results are also compared with other paleodata there is a good correlation with the six cold heinrich events between 70 and 15 ka b p a cooling event during the eemian period marked by high percentages of taxas at about 125 ka b p needs still to be correlated with high resolution ocean and ice cores

the climate and landscape of the middle part of the weichselian glaciation in europe the stage 3 project abstract oxygen isotope stage 3 ois 3 was a mild interval between the two cold maxima of the last weichselian glaciation marked by climate changes oscillating on a 100 1000 yr time scale between near interglacial and peak glacial conditions during ois 3 modern humans entered europe and somewhat later their neanderthal predecessors became extinct our understanding of this momentous event depends on an answer to the question did the unstable environmental conditions of the time play a significant role in early human history the stage 3 project is an interdisciplinary study with two main goals 1 to describe with existing data and to simulate the climates and landscapes of typical warm and cold phases between 45 000 and 30 000 yr ago and 2 to compare the results with the spatial and temporal distribution of human beings in this context this paper introduces the stage 3 project and provides background to a set of papers on the climate and landscape aspects of the project that will appear in quaternary research and to studies of their relevance to the early upper paleolithic of europe to appear in journals yet to be determined

sea surface temperature variability in the north atlantic during the last two glacial interglacial cycles comparison of faunal oxygen isotopic and mg ca derived records climate variability in the northeast atlantic was investigated on glacial interglacial and millennial time scales during the last 200 000 years using sea surface temperature sst records derived from planktonic foraminiferal diversities and from mg ca measurements on globigerina bulloides paleoceanographical interpretations are supported by species composition analyses benthic and planktonic isotopic data as well as records of iceberg rafted debris ird differences of climate development are recognized for both interglacial and glacial periods temperature estimates indicate slightly warmer conditions up to 2 c during marine oxygen isotope stage mis 5e than during the holocene in contrast to the last glaciation when the sst minimum coincided with a minimum in solar insolation immediately before termination i during the penultimate glaciation a long sst minimum occurred at times of intermediate solar insolation well preceding the onset of termination ii this discrepancy between two glacial terminations may be explained by an inherently different orbital configuration characteristic for each glacial interval despite these differences between the two glacial trends the superimposed shorter lived climatic events reveal the same order of principal steps implying their common causal nature a direct comparison of faunal ssts with those retrieved from mg ca analysis shows that mg ca derived temperatures follow the general glacial interglacial trend however the latter appear to be largely overestimated supported by 18o data in g bulloides which show little response to millennial scale variability there seems to be a need for species dependent calibration experiments that also consider the different oceanographic settings this particular species can live in

climatic reconstruction of the weichselian pleniglacial in northwestern and central europe a multiproxy approach is applied to reconstructing accurately the weichselian pleniglacial climate 72 13 ka in northwestern and central europe standardised translations are used to transform proxy data into climate parameter values for six characteristic time windows quantitative reconstructions of the temperature regime are derived from periglacial coleoptera and botanical evidence while aeolian and fluvial evidence provide qualitative information on wind activity and precipitation respectively the early pleniglacial 74 59 ka the cold period between 41 38 ka and the late pleniglacial 27 13 ka are characterised by a strong north to south climatic gradient over northwestern europe during the last glacial maximum discontinuous permafrost was established in northern france whereas the continuous permafrost zone extended from the uk belgium the netherlands germany and poland to the nordic ice sheets prominent wind activity and a relatively low precipitation typify these periods in contrast an indistinct west to east climate gradient was present in the relatively more temperate intervals e g 50 41 ka seasonally frozen ground conditions prevailed in northwestern europe whereas discontinuous permafrost may be suggested for central germany it appears that the climate conditions in northwest and central europe were controlled by three major factors the scandinavian ice sheet the north atlantic surface water circulation and the russian continent 1998 john wiley sons ltd

role of the thermohaline circulation in the abrupt warming after heinrich events evidence of rapid climate oscillations during the last glacial period has been identified in climate records from greenland ice cores1 2 and ocean sediments in the north atlantic3 4 these records show that periods of gradual cooling are terminated by abrupt warming events5 with the coldest periods coinciding with the deposition of ice rafted debris so called heinrich events throughout the north atlantic heinrich events are thought to be a signature of massive iceberg discharges owing to collapse of the laurentide ice sheet bond et al 5 have proposed that the decrease in meltwater flux following collapse and retreat of the ice sheet enhanced the ocean s thermohaline circulation6 thereby increasing advection of heat from the tropics and giving rise to abrupt climate warming here we test this idea using a simple ocean model coupled to a model of a periodically surging ice sheet we find that massive discharges of icebergs first stop the thermohaline circulation because of the consequent freshwater influx cooling the north atlantic region this is followed by a rapid restart of the circulation leading to abrupt warming thus our model can reproduce the qualitative features of the climate oscillations seen in the ice core and ocean records

increasing vegetation and climate gradient in western europe over the last glacial inception 122 110 ka data model comparison high resolution terrestrial pollen and marine planktic and benthic isotopes coarse fraction and n pachyderma s analyses have been performed in the marine isotope stage mis 5 interval of images core md99 2331 retrieved in the northwestern iberian margin this study shows the occurrence of a zeifen interstadial stadial succession on land and in the ocean during the first part of mis 5e in northwestern iberia the eemian is marked from 126 to 122 ka by the development of deciduous quercus forest at the same time as mediterranean forest colonised southern iberia and deciduous quercus corylus forest occupied northernmost european regions from 121 to 115 ka carpinus betulus forest developed in nw iberia indicating a winter cooling by 2degreesc on land and an increase in annual precipitation by 100 200 min along with a sea surface temperature sst decreasing trend off iberia a similar cooling has been documented at the same time in northern germany 52degreesn by the replacement of deciduous forest by coniferous abies picea formations implying a southward displacement of the deciduous tree line between similar to60degreesn and 50degreesn as early as 120 ka the southward migration of the tree line between 72degreesn and 58degreesn simulated by the earth model of intermediate complexity mobidic from 122 and 120 ka and considered as a major process to initiate the last glaciation is therefore compatible with data between 115 and 110 ka the substantial ice accumulation in northern high latitudes mis 5e 5d transition was synchronous with successive drops c26 and c25 in northeastern atlantic sst in northwestern iberia abies pinus trees developed at the expense of quercus carpinus forest a tundra like environment occupied northern germany marking the end of the interglacial in northwestern europe at 115 ka and boreal forest likely colonised northeastern france the first displacement of the vegetation belts at 121 ka was enhanced at 115 ka indicating an amplification of the vegetation and climate gradients in northeastern atlantic and european borderlands probably related with the well developed ice caps at that time the comparison between the general trend in the estimated and simulated mobidic winter and summer temperatures for latitudes between 35 and 45degreesn shows that both follow quite straightforwardly the precession signal although the simulated and reconstructed temperatures agree better in the south than north of 40degreesn annual precipitation is exhibiting opposite trend in the data and in the model this contradiction is likely the fact that the zonal climate simulated by the model may not accurately represent the regional climate features as reconstructed from the pollen c 2004 elsevier b v all rights reserved

a mutual climatic range method for reconstructing palaeoclimate from plant remains the mutual climatic range mcr technique for reconstructing palaeoclimate relies on establishing the present day climatic tolerance ranges of living species which are also found as fossils in quaternary deposits the palaeoclimate under which the species in a fossil assemblage co existed can be inferred to lie within the intersection of the individual species9 tolerance ranges this paper describes a factor analysis of modern european climate data to determine two compound variables that describe the main features of the climate 9summer warmth and dryness9 and 9wetness and winter warmth9 distribution maps of 80 plants from atlas florae europaeae were combined with the climate data to determine each species9 climatic range in factor space mcrs were determined for two living plant assemblages from southeast england and found to give a reliable although rather imprecise reconstruction of the true thermal and precipitation climate reconstructions for two plant macro fossil assemblages from devensian gravels at earith cambridgeshire demonstrated palaeoclimates that were colder and more continental than the present but with similar total amounts of precipitation the study demonstrates the potential of the mcr method for use with quaternary macrofossil plant remains although there are methodological drawbacks in employing a climate space defined by factor analysis

last glacial maximum climate of the former soviet union and mongolia reconstructed from pollen and plant macrofossil data an improved concept of the best analogues method was used to reconstruct the last glacial maximum lgm climate from a set of botanical records from the former soviet union and mongolia terrestrial pollen and macrofossil taxa were grouped into broad classes plant functional types pfts defined by the ecological and climatic parameters used in the biome1 model pft scores were then calibrated in terms of modern climate using 1245 surface pollen spectra from eurasia and north america in contrast to individual taxa which exhibit great variability and may not be present in the palaeoassemblages even in suitable climates pfts are more characteristic of the vegetation types the modified method thus allows climate reconstruction at time intervals with partial direct analogues of modern vegetation e g the lgm at 18 kbp mean temperatures were 20 29 degrees c colder than today in winter and 5 11 degrees c colder in summer in european russia and ukraine sites from western georgia show negative but moderate temperature anomalies compared to today 8 11 degrees c in january and 5 7 degrees c in july lgm winters were 7 15 degrees c colder and summers were 1 7 degrees c colder in siberia and mongolia annual precipitation sums were 50 750 mm lower than today across northern eurasia suggesting a weakening of the atlantic and pacific influences reconstructed drought index shows much drier lgm conditions in northern and mid latitude russia but similar to or slightly wetter than today around the black sea and in mongolia suggesting compensation of precipitation losses by lower than present evaporation

calibration of geomagnetic paleointensity data based on redeposition of sedimentary rocks abstract a new express method for redeposition of sedimentary rocks is proposed the method may be used for calibration of the ancient geomagnetic field intensity data obtained using sedimentary rocks the results of testing of the method for assessment of the intensity of ancient geomagnetic field using redeposition on the modern sediments formed in different climatic zones are presented it is shown that the error of a single determination of the magnetic field intensity on the contemporary marine sediments does not exceed 20 the results of determination of the ancient geomagnetic field intensity from sedimentary rocks available to date are summarized the average values of the paleointensity in the late cretaceous early jurassic late jurassic triassic permian late and early carboniferous obtained from sedimentary and thermomagnetized rocks has been compared it is revealed that sedimentary and thermomagnetized rocks have similar potentials for the assessment of the dynamics of the late paleozoic mesozoic paleointensity

quantitative interpretation of fossil pollen spectra dissimilarity coefficients and the method of modern analogs abstract dissimilarity coefficients measure the difference between multivariate samples and provide a quantitative aid to the identification of modern analogs for fossil pollen samples how eight coefficients responded to differences among modern pollen samples from eastern north america was tested these coefficients represent three different classes 1 unweighted coefficients that are most strongly influenced by large valued pollen types 2 equal weight coefficients that weight all pollen types equally but can be too sensitive to variations among rare types and 3 signal0to noise coefficients that are intermediate in their weighting of pollen types the studies with modern pollen allowed definition of critical values for each coefficient which when not exceeded indicate that two pollen samples originate from the same vegetation region dissimilarity coefficients were used to compare modern and fossil pollen samples and modern samples so similar to fossil samples were found that most of three late quaternary pollen diagrams could be reconstructed by substituting modern samples for fossil samples when the coefficients indicated that the fossil spectra had no modern analogs then the reconstructed diagrams did not match all aspects of the originals no modern analogs existed for samples from before 9300 yr b p at kirchner marsh minnesota and from before 11 000 yr b p at wintergreen lake michigan but modern analogs existed for almost all holocene samples from these two sites and brandreth bog new york

high resolution palynological record off the iberian margin direct land sea correlation for the last interglacial complex abstract we present high resolution pollen dinocyst and isotopic data for the last interglacial complex from marine core md952042 southwestern margin of the iberian peninsula 37 48 n 10 10 w 3148 m direct land sea correlation from this core indicates that during this period north atlantic sea surface temperatures were in phase with iberian climate our palynological analysis suggests a younger dryas like event at the marine isotope stage mis 6 5 transition the analysis also indicates that the eemian spans from the lightest isotopic values of mis 5e ca 126 ky bp to the heavier isotopic values towards the mis 5e 5d transition therefore the eemian is not entirely equivalent to mis 5e pollen analysis identifies four climatic phases of low amplitude during the eemian a mediterranean climate in southwestern europe is gradually replaced by oceanic conditions the middle of the eemian is characterized by an increase in precipitation on the land and ocean associated with a slight cooling this seems to be the result of a displacement of the polar front as far south as southern europe during this period after the eemian three relatively short climatic phases on land melisey i st germain ia and montaigu cold event occurred contemporaneously with three shifts of sea surface temperatures the montaigu event first identified in terrestrial pollen sequences is therefore also recorded in core md952042 on the basis of pollen dinocyst and planktonic isotopic data our results also show that the warm periods of mis 5 are not characterized by similar climatic conditions on land

chronostratigraphy of silt dominated pleistocene periglacial slope deposits on mt śleza sw poland palaeoenvironmental and pedogenic significance abstract slope deposits with aeolian silt admixture are a widespread parent material of soils in the temperate zone but may be neglected when rates of soil production are quantified the concept of periglacial cover beds differentiates slope deposits with or without aeolian silt admixture yet there is a remaining debate on processes and the timing of their formation a previous study done by us at mt leza sw poland concluded that slope deposits with variable aeolian silt admixture or its lack have a significant influence on the pathway of soil formation the present work builds upon this finding by adding further granulometric and micromorphological data from three representative profiles along a toposequence in order to refine our understanding of local slope deposits and soil formation additionally seven numerical ages using luminescence dating provide a chronological framework for our reconstructions and allow linking the forming processes of these pedosedimentary records to regional palaeoenvironmental conditions the oldest aeolian deposits are of middle pleistocene age 280 19 ka with interlayered palaeosol marine isotope stage mis 9 or older late pleistocene slope deposits encompass the maximum loess thickness and are dated to mis 2 luminescence ages from the upper layers indicate shallow reworking which we tentatively correlate to the younger dryas yd two profiles with thick loess mantles have strong clay illuviation features presumably formed during the holocene however weak clay illuviation in the third profile with a thin loess mantle having an age of yd over granite regolith seems to have occurred before the holocene as only fragmented clay coatings probably mis 2 pedogenesis could be found

ch4 and δ18o of o2 records from antarctic and greenland ice a clue for stratigraphic disturbance in the bottom part of the greenland ice core project and the greenland ice sheet project 2 ice cores the suggestion of climatic instability during the last interglacial period eem based on the bottom 10 of the greenland ice core project grip isotopic profile has been questioned because the bottom record from the neighboring greenland ice sheet project 2 gisp2 core 28 km away is strikingly different over the same interval and because records of the 18o of atmospheric o2 from both cores showed unexpected rapid fluctuations here we present detailed methane records from the vostok antarctica grip and gisp2 cores over the relevant intervals the grip and gisp2 data show rapid and large changes in methane concentration which are correlative with variations of the 18o of the ice while the vostok record shows no such variations this discrepancy reinforces the suggestion that the bottom sections of the greenland records are disturbed by combining the methane data with measurements of 18o of o2 in the same samples we attempt to constrain the nature of the stratigraphic disturbance and the age of the analyzed ice samples our results suggest that ice layers from part of the last interglacial period exist in the lower section of both ice cores and that some of the apparent climate instabilities in the grip core would be the result of a mixture of ice from the last interglacial with ice from the beginning of the last glaciation or from the penultimate glaciation

paleoclimatology of the achenheim series middle and upper pleistocene alsace france a malacological analysis abstract the loessic series of achenheim show an uninterrupted stratigraphical sequence dating from the middle and upper pleistocene they contain very abundant paleontological material especially land snails statistical analysis of the malacofaunas multivariate methods has allowed the reconstruction of the climatic evolution of that site during this period five cycles have been recognized which correspond to the glacial cycles b c d e and f comparison with the section of cerveny kopec czechoslovakia indicates the existence of a major climatic event during the pleniglacial of cycle d with a general expansion of the loess steppe in europe an environment which later never appeared in alsace the analogy of the climatic sedimentary sequences of cycle c suggests that alsace and central europe belong to the same geographical entity the development of alsace to an intermediary status between northwestern and central europe

vostok ice core provides 160 000 year record of atmospheric co2 direct evidence of past atmospheric co2 changes has been extended to the past 160 000 years from the vostok ice core these changes are most notably an inherent phenomenon of change between glacial and interglacial periods besides this major 100 000 year cycle the co2 record seems to exhibit a cyclic change with a period of some 21 000 years

a long pollen record from laghi di monticchio southern italy a preiminary account a pollen diagram from lake monticchio a volcanic crater lake in s central italy east of naples shows a long vegetation record for the holocene and the later portion of the last weichselian glacial period the upper 735 cm of a 2550 cm core is assigned to the holocene it begins with expansion of betula birch and quercus oak followed by fagus beech tilia lime and other mesic trees in the next phase the flora is dominated by oak with an increase in herb pollen in the later holocene the flora is again diversified by the appearance of abies fir curpinus hornbeam and other trees in the latest pleistocene portion of the core the vegetation is dominated by grasses artemisia sage brush and chenopods indicating a treeless environment the base of the core shows continued dominance by steppe like vegetation with 9interstadial9 episodes in which trees especially oak beech and fir were abundant the climatic interpretation is that the late pleistocene was very dry at least in the summer growing season and probably although not necessarily colder than now in the holocene increased precipitation favoured expansion of tree populations for a brief period there was a return of water stress in the growing season marked by a loss of tree species diversity and an increase in herbs in the later holocene a progressive diversification of tree species indicates a return to a more humid and perhaps cooler climate the vegetation history and climatic inferences are closely similar to records available from greece the available radiocarbon dates which show a consistent pattern indicate that the core is much older than 40000 years at the base but not old enough to include the major post eemian interstadials the 9holocene9 birch expansion began nearly 20000 years ago these dates appear to be systematically too old in the light of present knowledge the preliminary character of the study is emphasized further radiocarbon dates especially of the 9holocene9 section are needed as are more detailed studies of sedimentation processes and tephra occurrences

temperatures at the last interglacial simulated by a coupled ocean atmosphere climate model the last interglacial eemian 125 000 years ago has generally been considered the warmest time period in the last 200 000 years and thus sometimes been used as a reference for greenhouse projections herein we report results from a coupled ocean atmosphere climate model of the surface temperature response to changes in the radiative forcing at the last interglacial although the model generates the expected summer warming in the northern hemisphere winter cooling of a comparable magnitude occurs over north africa and tropical asia the global annual mean temperature for the eemian run is 0 3 degrees c cooler than the control run validation of simulated sea surface temperatures ssts against reconstructed ssts supports this conclusion and also the assumption that the flux correction fitted for the present state operates satisfactorily for modest perturbations our results imply that contrary to conventional expectations eemian global temperatures may already have been reached by the mid 20th century

asian provenance of glacial dust stage 2 in the greenland ice sheet project 2 ice core summit greenland samples of dust from the greenland ice sheet project 2 gisp2 ice core summit greenland dated within marine isotope stage 2 between 23 340 and 26 180 calendar years b p around the time of the coldest local last glacial temperatures have been analyzed to determine their provenance to accomplish this we have compared them with approximately coeval aeolian sediments mostly loesses sampled in possible source areas psas from around the northern hemisphere the 5 m grain size fraction of these samples was analyzed on the basis that it corresponds to the atmospheric dust component of that time and locale which was sufficiently fine grained to be transported over long distances on the basis of comparison of the clay mineralogy and sr nd and pb isotope composition with ice dust and psas and assuming that we have sampled the most important psas we have determined that the probable source area of these gisp2 dusts was in eastern asia the dust was not derived from either the midcontinental united states or the sahara two more proximal areas that have been suggested as potential sources based on atmospheric circulation modeling except for a brief period during an interstadial when dust transport was exceptionally low for glacial times and had a mineralogical composition indicative of a slightly more southern provenance the source area of the dust did not change significantly during times of variably higher fluxes of dust with larger mean grain size or lower fluxes of dust with smaller mean grain size this includes the high dust period that correlates with the heinrich 2 period of major iceberg discharge into the north atlantic variable wind strengths must therefore be invoked to account for these abrupt and significant changes in dust flux and grain size

towards a middle pleistocene terrestrial climate reconstruction based on herpetofaunal assemblages from the iberian peninsula state of the art and perspectives abstract the pattern of the varying climatic conditions in southern europe over the last million years is well known from isotope studies on deep ocean sediment cores and the long pollen records that have been produced for lacustrine and marine sedimentary sequences from greece italy and the iberian margin however although relative glacial and interglacial intensities are well studied there are still few proxies that permit quantitative terrestrial temperature and precipitation reconstruction in this context fauna based climate reconstructions based on evidence preserved in archaeological or palaeontological sites are of great interest even if they only document short windows of that climate variability because a they provide a range of temperature and precipitation estimates that are understandable in comparison with present climate b they may allow the testing of predicted temperature changes under scenarios of future climate change and c quantitative temperature and precipitation estimates for past glacials and interglacials for specific regions latitudes can help to understand their effects on flora fauna and hominids as they are directly associated with those cultural and or biological events moreover such reconstructions can bring further arguments to the discussion about important climatic events like the mid bruhnes event a climatic transition between moderate warmths and greater warmths during interglacials in this paper we review a decade of amphibian and reptile based climate reconstructions carried out for the iberian peninsula using the mutual ecogeographic range method in order to present a regional synthesis from mis 22 to mis 6 discuss the climate pattern in relation to the mid bruhnes event and the thermal amplitude suggested by these estimates and finally to identify the chronological gaps that have still to be investigated

dissimilarity mapping between fossil and contemporary pollen spectra in europe for the past 13 000 years abstract the degree of analogy between fossil and contemporary pollen spectra in europe has been investigated using the chord distance dissimilarity measure no analog pollen spectra represent vegetation without a modern analog and hence by inference represent macroclimatic conditions different from any occurring in the region today such spectra have minimum chord distances that exceed a threshold value assessed using contemporary samples from the same and different vegetation u units contoured maps of minimum chord distance portray the changing patterns of analogous and no analog pollen spectra and hence vegetation units since 13 000 yr b p no analog vegetation units have been extensive in some regions for much of the holocene persisting as recently as 1000 years ago in many areas the chord distance measure has also been used to explore the patterns extent and rates of change in european pollen spectra since 13 000 yr b p pollen spectra changed rapidly during late glacial and early holocene times and during the last millennium paleoclimatic changes have brought about the major changes in the holocene paleovegetation of europe human impact upon european vegetation has obscured neither the contemporary relationship between pollen spectra and vegetation nor the climatically determined long term changes of vegetation across the continent since 13 000 yr b p

the last climatic cycle at la grande pile vosges france a new pollen profile a new pollen diagram has been made from an old unanalyzed core from la grande pile gp xx correlations with the previous work of woillard 1975 1978 leads to the following conclusions the end of the eemian was marked by a minor climatic change prior to the melisey i stadial the ognon ii and ognon iii interstadials are not consistent and correspond to the level of reworking of mesophilous taxa during the last pleniglacial the limitations of the botanical interpretation of pollen spectra from the last pleniglacial are underlined lastly bruckenthalia and larix are identified for the first time at la grande pile the respective roles of these taxa following the eemian are additional arguments for correlating the st germain i and ii with the early weichsel interstadials in the north of middle europe

rissian eemian and wurmian coleoptera assemblages from la grande pile vosges france abstract the grande pile peat bog sequence is one of the few west european sites that cover the entire time span of the last major climatic cycle 140 000 years a recent program of coring has provided material for insect analysis the aim of this palaeoentomological study is to interpret the environmental and climatic evolution from the end of the rissian glaciation to the holocene using subfossil coleoptera the studied samples yielded 394 taxa of coleoptera half of them identified to species level 19 of which do not belong to the present day french fauna the large number of taxa suggests a wide variety of habitats and provides much detailed palaeoecological evidence for the period studied the lowermost sediments of the sequence corresponding to the end of the rissian glaciation were deposited under very cold conditions in a tundra environment this is succeeded by a forest period in which two cool interludes of grassland environment occur although these periods are decidedly poor in tree dependent coleoptera they do not contain any really cold adapted taxa they divide the forest phase into three periods the first one corresponding to the eemian interglacial shows an early stage in which the beetle fauna is characterized by species dependent on deciduous trees a later stage in which this fauna is mixed with many conifer dependent elements some of which e g platypus oxyurus suggest warmer and perhaps wetter climatic condition than today the two later woodland periods yielded coleopteran assemblages rather similar to those recorded in the second part of the eemian i e with both deciduous and conifer dependent taxa there is some evidence to suggest that these two periods were slightly cooler than the eemian proper marked climatic deterioration becomes obvious in the upper half of the sedimentary sequence attributed to the last glacial period wurm with the reappearance of tundra beetle assemblages sediment and insect evidence suggest that the climate was extremely cold and continental at la grande pile at about 30 000 b p a comparison of the insect analysis with previous palynological works enables precise correlation between the results provided by these two independent approaches however large numbers of running water coleoptera in the forest periods replaced by standing water coleoptera in cold periods raise questions concerning the lacustrine origin of the sedimentation at la grande pile

late quaternary climatic change in france estimated from multivariate pollen time series abstract in regions like southern france where usual analytical techniques are unsatisfactory due to the heavy influence of human activity and the existence of a complex climate the quantitative reconstruction of climate from pollen is particularly difficult that is why an original method has been performed the first step of the method based on best analogs estimation and multiple regression is to calculate a relationship between climate monthly temperature and precipitation and modern pollen spectra for data from 182 sites the result is called the analog climate the second step of the method an original combination of canonical correlation and principal components analyses extracts the common information from several fossil pollen sequences to produce a so called paleobioclimate this step removes the effects of local differences in the vegetation among nearby sites and also reduces the effects of human disturbance in the third step the signals obtained from the first two steps are merged by kalman filter into a final reconstruction where the noise is reduced by around 37 the results presented with a 95 confidence level suggest that the pleni wurm was 7 to 13 c colder than present and had 20 to 60 less precipitation than today this large confidence takes into account the climatic diversity of the region at 13 000 yr b p the climate reached the modern level of precipitation but the temperature was just less than present the subsequent decrease of precipitation is less important than that of temperature this fact may explain the advance of alpine glaciers during the younger dryas preboreal warming was abrupt 3 to 4 c per 500 yr and precipitation increased more slowly

eemian and early weichselian 140 60 ka paleoceanography and paleoclimate in the nordic seas with comparisons to holocene conditions paleoceanographic and paleoclimatic time series were extracted from norwegian iceland and greenland sea the nordic seas sediment sequences covering the time intervals 60 140 ka and 0 15 ka on the basis of stable isotope stratigraphy planktonic foraminiferal faunas and sedimentological methods the proxy temperature records from the norwegian iceland sea display a number of high frequency and high amplitude variations within the last interglacial the eemian indicating marked changes in heat flux at high northern latitudes eemian holocene comparisons document that the climate of the norwegian iceland sea in the last interglacial was less stable than that of the present interglacial and that the distribution of surface water masses in the eemian differed from that of the holocene within the greenland sea uniform cold conditions prevailed throughout both interglacials cooling of the nordic seas as well as the initial growth of the surrounding ice sheets began within the eemian interval before the main increase in global ice volume heat flux to the nordic seas was significantly higher during the interglacials than at any time during the early weichselian 60 113 ka and no marked stadial interstadial changes in sea surface temperature and deep water ventilation are documented in the early weichselian records contrary to the pattern found in north atlantic sediment records however fluctuations in planktonic foraminiferal content planktonic 13c and ice rafting on suborbital timescales mostly comparable in number and age to the stadial interstadial fluctuations in the greenland ice cores are demonstrated in our records the ice rafted detritus records provide a more detailed account of ice sheet variability than previously known for the early weichselian period and demonstrate that glaciers advanced to sea level somewhere around the nordic seas several times during this interval

evidence for large amplitude biome and climate changes in atlantic canada during the last interglacial and mid wisconsinan periods abstract last interglacial and mid wisconsinan pollen data from sedimentary sequences of cape breton island in atlantic canada were analyzed to reconstruct biome and climate conditions our results show warm and humid climate with mean annual temperature 6 7 c higher than today up to 15 20 more sunshine and significantly longer growing season that fostered growth of temperate trees during the optimum of the last interglacial the northern limit of the deciduous forest biome was then about 500 km north of its modern limit towards the end of the interglacial the deciduous forest was replaced by conifer hardwood forest and boreal forest climate was then similar to modern the transition from interglacial to glacial was marked by a change towards coniferous forest related to colder and dryer conditions during the mid wisconsinan the development of forest tundra to boreal forest reflects migration of the arctic front and significant cooling with mean annual temperature anomalies of 8 to 12 c the overall time series reflect large amplitude climate changes that point to high sensitivity of the southeastern canadian margins likely as a response to latitudinal shifts of the gulf stream and variable strength of the labrador current together with changes in large scale atmospheric circulation pattern

tentative palaeoclimatic reconstruction linking pollen and sedimentology in la grande pile vosges france quantitative values of palaeotemperature and palaeoprecipitation were reconstructed from pollen record in la grande pile guiot et al 1989 some weaknesses appear in the reconstruction particularly for the cold periods and for the periods of deglaciation from sedimentological data i e organic carbon content periglacial loess content and smectite content it is attempted to refine the palaeoclimate reconstruction more accurate values are calculated between the upper and the lower limits of the pollen data during the deltao 18 stages 4 and 2 of the last glacial cycle the climate was the coldest and the driest it was less cold and more humid during the stage 3

high frequency pulses of east asian monsoon climate in the last two glaciations link with the north atlantic three loess sections in the loess plateau of china have been studied to characterize the variations of the east asian monsoon climate in the late quaternary period paleo weathering profiles based on two weathering indices reveal a series of spatially correlative intervals of lower weathering intensity lw in the last glacial and late penultimate glacial loess indicating significantly cooler or and drier conditions most of them are identified at or near the transitional boundaries between loess and soil units suggesting that climatic conditions favorable for lw events tended to occur at or near major climatic boundaries twenty eight radiocarbon and thermoluminescence measurements combined with kukla s magnetic susceptibility age model date these events at 14 21 29 38 52 71 135 and 145 ka bp with 5 10 ka frequency inlaid within the orbitally induced 20 ka periodicity the ages of the first six events in the last glacial period are therefore close to those of the coarse grained heinrich layers in the north atlantic ocean which resulted from massive discharges of icebergs the results indicate that the climate in the area affected by the east asian monsoon has experienced high frequency changes more or less synchronous with the heinrich events these high frequency changes have been reported by porter and an based on the grain size time series from the luochuan loess section our data also reveal that similar events also occurred during the penultimate glaciation the mechanisms linking the heinrich events and the east asian monsoon climate may be similar to that driving the younger dryas event which has been identified in a large number of records in china and in the surrounding oceans

eemian climate fluctuations observed in a european pollen record recent ice core data from greenland1 2 suggest that the climate during the last interglacial period the eemian was more unstable than that of the holocene about 10 000 years ago to the present being characterized in particular by a series of cold episodes each lasting about 70 to 750 years subsequent analysis of a second greenland ice core3 4 however failed to corroborate the details of these eemian climate fluctuations a result that may be attributable to the effects of ice flow4 to resolve this discrepancy it is imperative to seek alternative sources of information about the eemian climate here we present climate reconstructions from pollen data from the annually laminated eemian lake sediment record at bispingen5 and from the eemian and holocene peat records at la grande pile6 the former record indicates that an initially warm period of 2 900 yr was followed by cooling and a series of colder episodes one of which had winter temperatures comparable to those at the end of the preceding cold stage the latter records show greater climate instability during the eemian than the holocene these results are in broad agreement with those from the grip ice core but contrast both with the gisp2 core3 4 and with recent high resolution marine records from the north atlantic7 8

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

stratigraphy palaeoenvironments and model for the deposition of the abdur reef limestone context for an important archaeological site from the last interglacial on the red sea coast of eritrea stone tools discovered within uplifted marine terraces along the red sea coast of eritrea at the abdur archaeological site dated to 125 7 ka the last interglacial marine isotope stage 5e show that early humans occupied coastal areas by this time walter et al 2000 nature 405 65 69 in the present paper the stratigraphy facies types and faunal composition from 25 measured sections of the tool bearing abdur reef limestone arl are documented in detail and interpreted to provide a palaeoenvironmental context for the stone artefacts and a model for the deposition of the arl the arl represents a complex marine terrace sequence erosional surfaces indicative of interrupted sedimentation are locally observed at two levels within the arl they subdivide the complex into three subunits named 5e1 5e2 and 5e3 representing different stages of the marine isotope stage 5e sea level highstand comprising six depositional phases i vi of the arl subunit 5e1 begins with the initial transgression of the 5e sea level highstand leading to the deposition of widespread lag gravels on which rich oyster beds developed in shallow water phase i it further records rapid deepening accompanied by the deposition of low energy carbonates with scarce corals phase ii and later shoaling characterised by local development of a fringing reef tract in a sedimented environment phase iii subunit 5e1 is capped locally by a burrowed hardground that is laterally equivalent to depositional discontinuities interpreted as caused by a globally recognised mid 5e sea level low stand phase iv extensive reef build up in response to sea level rise and improved conditions for coral growth characterises subunit 5e2 phase v a possible second sea level drop during the 5e highstand is inferred from the oyster encrusted upper surface of subunit 5e2 subunit 5e3 encompasses restricted coral patches that developed on the upper surface of the underlying subunit during the last stage of the 5e marine high stand phase vi two different toolkits are found in the arl one consists of bifacial hand axes and cores of the acheulian industry typically associated with the oyster beds encrusted on the transgressive lag deposits the other consists of middle stone age msa type obsidian flakes and blades mainly found in the nearshore and beach environments alongside debris from marine invertebrates and large land mammals the distribution of these tools suggests that foraging activities of early humans varied with environmental setting the abdur archaeological site represents a late example of the acheulian msa transition seen as a benchmark for early modern human behaviour and is to date the earliest well dated example of early human adaptation to marine food resources

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

magnetic susceptibility applied as an age depth climate relative dating technique using sediments from scladina cave a late pleistocene cave site in belgium abstract here we demonstrate that magnetic susceptibility ms data from scladina cave belgium provide a time depth climate relationship that is correlated to the marine oxygen isotopic record and thus yields a high resolution relative dating method for sediments recovered from many archaeological sites this methodology will help resolve one of the major problems facing archaeologists namely the difficulty of acquiring absolute dates with reasonable precision for the period from 40 000 to 400 000 years or so the problem is that dating techniques applicable to most materials within this age range are subject to significant errors relative dating techniques such as magnetic secular variation or stable isotope methods offer the potential to improve this precision but both methods suffer from problems that make broad application to many sites impossible however for most archaeological cave sites ms measurements of cave sediments offers the potential for intra site correlation and paleoclimate estimation this is possible in protected cave environments because the ms of cave sediments results from climate processes active outside caves which cause variations in magnetic properties of the sediments that ultimately accumulate inside caves once deposited these materials are often preserved and their stratigraphy provides a time depth climate signal that can be identified therefore ms data can be used as an independent methodology alongside conventional methods such as sedimentology and palynology for relative age dates and correlation within and between sites by tracing evidence of paleoclimatic change this correlation has been used to infer an age of 90 000 7000 years for neanderthal skeletal remains recovered from scladina cave an important middle paleolithic archaeological site in belgium

eemian climatic and hydrographical instability on a marine shelf in northern denmark abstract benthic foraminifera and stable isotope data from the last interglaciation eemian substage 5e from a borehole at skagen denmark provide evidence for major environmental and hydrographic changes during this period during the first millennium of the eemian water masses covering northern denmark became gradually warmer temperate conditions prevailed during most of the interglaciation but these were interrupted by two periods with decreased water temperatures the first cooling event s 1 was not very distinct at skagen but the second event s 2 seen in both the foraminiferal and oxygen isotope record represents a large shift to subarctic conditions carbon isotopes indicate a change in ocean circulation during both events no comparable climate variations are seen within the holocene record at the site the final cooling of the water masses associated with the substage 5e 5d boundary occurred within a few hundred years these last interglacial climatic changes were probably caused by variations in strength and or position of the north atlantic drift possibly as a result of varying vigor of the atlantic conveyor in addition minor variations in the fossil assemblages also indicate fluctuations in the inflow of atlantic water to the skagerrak kattegat area during the warm intervals of substage 5e

pollen inferred palaeoclimate reconstruction in the alps during the lateglacial and the early holocene how to estimate the effect of elevation and local parameters the modern analogue technique mat was applied to six pollen sequences from the belledonne massif northwestern french alps to estimate the effect of altitude and local parameters on pollen based climate reconstruction during the lateglacial and the early holocene the six sites le vivier 345 m a s l les etelles 700 m a s l la coche 980 m a s l montendry 1330 m a s l le grand leyat 1660 m a s l la gouille 1800 m a s l are located in different vegetation belts mixed deciduous woods conifer woods alpine pastures with maple the main vegetation changes in the past are recorded at each site the evolution of four climate parameters coldest month temperature warmest month temperature mean annual temperature annual precipitation was quantitatively inferred from pollen data using mat the curves obtained were compared to the les etelles site which was the least affected by non local pollen transport the results show consistent trends for the climate parameters reconstructed at the different sites however the reconstruction does not indicate a decrease in temperature values related to the increasing elevation difficulties in reconstructing the altitudinal variations of climate parameters from pollen data during the periods studied are discussed and perspectives for improvement are considered copyright 2009 john wiley sons ltd

direct land sea correlations in the last interglacial complex isotopic and pollen analyses of an eastern atlantic core permit the first direct correlation of substages 5e and 5c of the marine climatostratigraphical system with the eemian and st germain i respectively of the classical grande pile pollen sequence north east france the vegetational sequences during the warm intervals of the last interglacial complex 125 000 75 000 yr bp indicate that climatic deterioration occurred late on the mid european continent after the initiation of glaciation over continental masses in high latitudes

age dating and the orbital theory of the ice ages development of a high resolution 0 to 300 000 year chronostratigraphy using the concept of orbital tuning a continuous high resolution deep sea chronostratigraphy has been developed spanning the last 300 000 yr the chronology is developed using a stacked oxygen isotope stratigraphy and four different orbital tuning approaches each of which is based upon a different assumption concerning the response of the orbital signal recorded in the data each approach yields a separate chronology the error measured by the standard deviation about the average of these four results which represents the best chronology has an average magnitude of only 2500 yr this small value indicates that the chronology produced is insensitive to the specific orbital tuning technique used excellent convergence between chronologies developed using each of five different paleoclimatological indicators from a single core is also obtained the resultant chronology is also insensitive to the specific indicator used the error associated with each tuning approach is estimated independently and propagated through to the average result the resulting error estimate is independent of that associated with the degree of convergence and has an average magnitude of 3500 yr in excellent agreement with the 2500 yr estimate transfer of the final chronology to the stacked record leads to an estimated error of 1500 yr thus the final chronology has an average error of 5000 yr