environmental inferences and chironomid based temperature reconstructions from fragmentary records of the weichselian early glacial and pleniglacial periods in the niederlausitz area eastern germany abstract we inferred past climate conditions from lacustrine sediments intercalated in weichselian early glacial and early pleniglacial fluvial and aeolian sediments exposed in two opencast lignite mines from the niederlausitz area eastern germany a chronology was established using radiocarbon and luminescence dating methods both lithology and chironomid fauna indicate that the former shallow lakes were situated on a floodplain palaeotemperature estimates calculated from the fossil chironomid assemblages of the early glacial lacustrine deposit indicate mean july air temperatures of ca 15 c which is in line with results derived in earlier studies from the niederlausitz area and from northwestern europe the early pleniglacial lacustrine deposits consist of an organic rich gyttja intercalated with sand and silt lenses the chironomid assemblages show that a shallow meso to eutrophic lake was present at the study site and chironomid inferred palaeotemperature estimates indicate an abrupt decline in july air temperatures from 15 16 c to ca 13 c in combination with other proxies from the same record this suggests a dansgaard oeschger like climate event

short climatic oscillations in a western european loess sequence kesselt belgium this new study of the loess section at kesselt is focused mainly on the reconstruction of palaeoenvironments of the last glacial period in the belgian dutch region detailed grain size analyses in combination with the study of the palaeosols and periglacial structures indicate the occurrence of climatic cycles during loess deposition permafrost development coincided with enhanced deposition of relatively coarse loess and alternated with permafrost degradation decreased deposition of finer loess and tundra soil formation a newly designated palaeosol lafelt soil is described in detail particularly in terms of its micromorphological properties it is a luvisol and its chronostratigraphical position is still open to debate but radiocarbon dating places it in the weichselian middle pleniglacial 1998 john wiley sons ltd

biostratigraphy of the last glacial period in europe the european early weichselian early wurmian is characterized by two long and relatively warm interstadials brorup and odderade which can be traced and correlated with certainty across large parts of europe the amersfoort interstadial described earlier from the netherlands has been included in the brorup and represents the older part of it both great interstadials were forested in north west central and southern europe in the north conifer forests prevailed giving way towards the south to deciduous forests the climatic gradient was distinctly steeper mainly due to southward displacement of the gulf stream the two great interstadials are synchronous with the isotopic stages 5a and 5c in the deep sea cores subsequent to eemian brorup and odderade and from within the context of a continuous series two additional and clearly delimited interstadials have been recorded in a new standard profile from oerel nw germany these are now described as the oerel and glinde interstadials they were not forested and belong to the early pleni weichselian the lower one oerel can probably be correlated with the 3rd weichselian wurmian interstadial in southern central europe ognon ii durnten samerberg 3 while the upper one glinde has so far no known counterpart for the younger pleni glacial it is assumed that there was a long phase during which it was not too cold the formation of humic layers during this phase took place at different times partly due to local edaphic factors so that the relevant 14c dates show a wide scatter the hengelo and denekamp interstadials represent only slight ameliorations which facilitated the formation of shrub tundra and can be recorded in certain regions only

age and origin of clayey silt brickearth in west london england the loamy brickearth deposits overlying coarse cold climate kempton park lynch hill and taplow gravels of the r thames in west london are dated by thermoluminescence and mineralogical comparisons with loesses of three known ages although much of the brickearth resembles loess it often contains more sand or clay than typical loess and the mineralogical studies suggest that even the coarse silt 16 63 m fraction is rarely similar in composition to any known english loess the thermoluminescence measurements suggest that most of the brickearth on the taplow and lynch hill gravels was deposited in the late devensian whereas that on the park gravel is mainly flandrian it is suggested that the latter is mainly floodloam whereas the earlier brickearth is a mixed aeolian sediment derived from various local sources in and close to the thames valley

u series dating of the late pleistocene mammalian fauna from wood quarry steetley nottinghamshire uk we present the u series dating of bones from wood quarry steetley quarry cave using the diffusion adsorption model to account for uranium uptake the results give a weighted mean date of 66 8 3 0 kyr placing this assemblage within or just before marine oxygen isotope stage 4 the fauna is thought to correlate with the banwell bone cave mammal assemblage zone of the early devensian in britain our results support the idea that this assemblage zone immediately precedes the assemblage represented nearby at pin hole in creswell crags which is contemporary with the mid devensian and correlates with mis 3 our dates and dates for the banwell bone cave mammal assemblage zone from stump cross cavern and evidence from other sites may indicate a longevity for this fauna copyright 2005 john wiley sons ltd

validity of the radiocarbon dates beyond 35 000 years b p abstract if we take in account both the different kinds of material used for 14c dating and the old and new methods of sample preparation it is possible to estimate the reliability of the oldest of all the radiocarbon dates published it becomes clear that most of them should be considered as minimal ages and in particular those which were obtained by the isotopic enrichment method consequently all the radiocarbon ages attributed to the first interstadials of the early wurm may be considered as too young

palaeontology and taphonomy of late quaternary fossil assemblages at somersham cambridgeshire england and the problem of reworking assemblages of foraminifers ostracods and molluscs from temperate ipswichian stage last temperate stage sediments and overlying cold devensian stage last cold stage sediments at somersham in the southern fenland of cambridgeshire have been analysed the ipswichian sediments contain faunas consistent with temperate brackish water conditions under tidal influence the devensian assemblages were recovered from a series of sands and gravels laterally accreting in a channel cutting into ipswichian sediments in contrast to the ipswichian faunas the faunas of particular devensian samples show a complex mixture of temperate freshwater brackish and marine taxa the molluscs are mainly freshwater with few land snails they occur together with foraminifers and ostracods freshwater brackish water and marine ostracods are present with foraminifers a sample of devensian fine laminated sediment in the channel was analysed for pollen only abundant pre quaternary spores were present with abundant foraminifers in the same sample the taphonomy of the assemblages and the difficulties of their interpretation in environmental terms are discussed the importance of taphonomy in assessing environments climate range of taxa and dating is stressed

climatic and environmental reconstructions based on fossil assemblages from middle devensian weichselian deposits of the river thames at south kensington central london uk abstract fossiliferous silts within the late pleistocene kempton park gravel of the river thames valley were exposed in 1980 during foundation works for the ismaili centre in south kensington london the results of a multidisciplinary study of the geomorphology sediments fossil plants vertebrates molluscs ostracods and insects are reported the silts were deposited under two distinct climatic regimes a lower unit accumulated when the climate was arctic and an upper when the temperatures were at least as warm as those of the present day both these units occupy the same channel system and are separated from one another by less than a metre of sediment implying that the climatic change was probably sudden and intense the strongest evidence for this climatic difference comes from a study of the coleoptera which show an almost complete replacement of the arctic element in the fauna by a suite of temperate species palaeotemperature reconstructions using the mutual climatic range method based on the coleopteran assemblages from the lower unit suggest that the mean temperature of the warmest month was 9 2 c and that of the coldest month 22 10 c for the upper unit the mean temperature of the warmest month had risen to about 17 c and that of the coldest month to about 4 c the episode represented by the lower unit with its arctic climate had not previously been recognized in the thames valley the fauna from the upper temperate unit is very similar to that from other sites in the kempton park gravel such as that from isleworth 10 km upriver which like the upper unit at the ismaili centre was characterized by the virtual absence of trees it would appear that in such cases this treelessness does not indicate cold conditions equivalent to those of the modern tundra but may instead result from a combination of ecological and temporal factors the value of multidisciplinary studies in reaching such conclusions is emphasized the temperate episode described here is correlated with the thermal maximum at the early part of the upton warren interstadial complex an earlier suggestion based on amino acid epimerization ratios that the upton warren interstadial correlates with oxygen isotope sub stage 5a is not supported by the data which show no evidence of the forested environments that characterized this period in both britain and the adjacent continent it is thought that the temperate deposits at the ismaili centre belong to the middle pleniglacial rather than the early devensian weichselian and are equivalent to oxygen isotope stage 3

modest summer temperature variability during do cycles in western europe abrupt climatic shifts between cold stadials and warm interstadials termed dansgaard oeschger do cycles occurred frequently during the last glacial their imprint is registered in paleorecords

the upper pleistocene deposits at cassington near oxford england for much of the middle and all of the upper pleistocene the upper thames valley has remained outside the limit of ice advance the main agents of landform evolution have been the river thames and its tributaries which have cut down episodically and in so doing have abandoned a series of river terraces this study reports the findings of an investigation into exposures in the deposits underlying the floodplain terrace at cassington near oxford england the sequence exposed reveals a stratigraphy of basal predominantly fine grained lithofacies overlain by coarser gravel lithofacies the fluvial architecture of these deposits indicates a major change in fluvial style from a low energy meandering to a high energy braided channel system the flora and fauna from the lower fine grained lithofacies display a marked change from temperate at the base to colder conditions towards the top indicating a close association between deteriorating climate and changing fluvial depositional style amino acid and luminescence geochronology from the basal fine grained lithofacies suggest correlation with oxygen isotope stage 5 and hence it is argued that the major environmental change recorded at the site relates to the oxygen isotope stage 5 4 transition deposition of much of the overlying gravel sequence probably occurred during oxygen isotope stage 4 suggesting that the latter half of the devensian may be less significant in terms of fluvial landscape evolution in the upper thames valley than was believed previously c 1998 john wiley sons ltd

periglacial fluvial systems in northwest europe during marine isotope stages 4 and 3 comparison of fluvial successions in river valleys dating from marine isotope mi stages 4 and 3 in a west east transect from britain to poland shows the spatial and temporal variation in palaeohydrological characteristics of northwest european river valleys during these stages mi stage 4 has been a period of deep fluvial incision following this erosion most valleys were filled during mi stage 3 with successions of gravelly river deposits britain or sand silt peat successions northwest european lowlands the sedimentology of the deposits suggests strong discharge variations caused by a nival discharge regime with pronounced spring snowmelt discharges the mi stage 3 climate oscillations generally cannot be traced in the fluvial record an incision phase of hengelo interstadial age has been found in the netherlands but similar incision phases related to other warming events have not been proved convincingly the restricted reaction of the river systems is caused by the absence of geomorphologically effective vegetation changes and relatively minor variations in precipitation during mi stage 3 over longer time scales silt and peat beds gradually decrease in the younger post hengelo upton warren part of mi stage 3 corresponding with evidence of aeolian activity and permafrost this is related to the longer duration of the stadials in this part of mi stage 3

numerical simulation of barotropic jets over a sloping bottom comparison to a laboratory model of the northern current 1 in order to study the role of a sloping bottom on the mesoscale variability of the northern current a series of barotropic laboratory experiments was performed on a rotating table setup the present work is devoted to a numerical model which aims to simulate these laboratory conditions in order to further investigate aspects which are difficult to treat in the laboratory the onset of instabilities the influence of the velocity profile the relative position of the jet over the slope and the influence of the jet width on the resulting instabilities are discussed the robustness and the origin of a shelf break topographic rossby wave detected in our westward laboratory flows is also discussed the barotropic model for westward currents such as the northern current with rossby numbers in the range ro 0 1 0 2 predicts wavelengths of 50 75 km similar to those observed in sst images the periods associated with the model instabilities 3 3 3 8 days would be close to a 3 5 day band of mesoscale activity recorded from current meter devices in the gulf of lions which lies out of the traditionally considered baroclinic instability theory other particularities such as the up slope migration of the northern current and the increasing mesoscale activity for increasing jet velocities can also be explained through the present model these results would point out barotropic instability as a factor to consider apart from the traditional idea of baroclinic instability in order to partially explain the northern current mesoscale variability

quaternary river terraces in england forms sediments and processes abstract flights of quaternary river terraces in south and east england have common characteristics involving low gradient planed or irregular bedrock surfaces and single or multi storey gravel deposits rather than depending on warm cold or cold warm transitions it is suggested that bedrock planation working depths of gravel and later stage relatively shallow aggradations are all dominantly of cold climate origin basal sediments show active incorporation of plucked and periglacially shattered materials whilst super incumbent units incorporating up catchment and slope derived materials demonstrate later cold stage sediment influx and consequent cessation of active bedrock erosion channel activity effecting both planation and deposition are reviewed together with the detailed sedimentology of gravelly sediments which show evidence of both autogenic processes bar migration channel switching and infilling and truncation of upper sedimentation units cold climate indicators turbation ice wedge casts and frozen block transport and specifically for the last glacial interglacial cycle varying sediment flux as climates changed both interglacial and transitional activities are believed to be of lesser morphological significance whilst prior uplift is taken as enabling rather than being a generator of terrace within the timescale of a glacial interglacial cycle variations within cold stage climates varying sediment influx and channel belt bedrock erosion are stressed as dominating mid catchment and mid latitude quaternary terracing at the glacial interglacial scale

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

recent tims dating results from british late pleistocene vertebrate faunal localities context and interpretation new tims dates from british sites underpin and extend the growing model of mammalian faunal history during the late pleistocene the sequence of british faunas during the three successive warm phases of mis 5 presents a challenging model in which the mammal faunas of the first two temperate phases 5e and 5c is dominated by species of a classically interglacial character while that of the final phase sub stage 5a is dominated by bison and reindeer this we see as the cold fauna appearing in britain during the cool isotope sub stage 5b and subsequently isolated by the rising sea level of isotope sub stage 5a all these three faunas are true island faunas copyright 2007 john wiley sons ltd

the nature of mis 3 stadial interstadial transitions in europe new insights from model data comparisons 15 abrupt warming transitions perturbed glacial climate in greenland during marine isotope stage 3 mis 3 60 27 ka bp one hypothesis states that the 8 16 degrees c warming between greenland stad

low frequency waves in the ligurian sea during december 1977 observations of low frequency waves in the ligurian sea in december 1977 are presented from time series of thermal infrared images obtained by satellite noaa 5 the mean wavelength and phase velocity are estimated they are respectively 38 km and 18 cm s 1 these waves are analyzed as large amplitude baroclinic waves fairly good agreement is found with a two layer model

the behavior of jet currents over a continental slope topography with a possible application to the northern current abstract the northern current is a slope current in the northwest mediterranean that shows high mesoscale variability generally associated with meander and eddy formation a barotropic laboratory model of this current is used here to study the role of the bottom topography on the current variability for this purpose a source sink setup in a cylindrical tank placed on a rotating table is used to generate an axisymmetric barotropic current to study inviscid topographic effects experiments are performed over a topographic slope and also over a constant depth setup the latter being used as a reference for the former with the aim of obtaining a fully comprehensive view of the vorticity balance at play the flow may be forced in either azimuthal direction leading to a westward prograde current similar to the northern current or an eastward retrograde current for slow flows eastward and westward currents showed similar patterns dominated by kelvin helmholtz type instabilities for high speed flo

circulation over a submarine canyon in the nw mediterranean 1 the circulation in blanes canyon an interruption in the nw mediterranean continental shelf north of barcelona was investigated the study employs data from oceanographic surveys carried out in the summer and fall of 2003 velocity data show that in the vicinity of the shelf break the flow is deflected along the canyon walls a cyclonic mean flow can be seen over the canyon mouth owing to vortex stretching of fluid parcels advected across the shelf break field observations are in qualitative agreement with fundamental fluid dynamic considerations based on potential vorticity conservation and friction effects at lateral boundaries evidence is given that upwelling is found near the shelf break inside the canyon in the two field experiments this upwelling extends vertically from the seasonal thermocline at about 100 m to the shelf slope front at about 200 m there is no evidence that upwelled water can reach the continental shelf

deep flow variability in a deeply incised mediterranean submarine valley blanes canyon abstract deep flow variability in blanes canyon is analyzed by means of a unique dataset in which the canyon was instrumented at its axis and at the two canyon walls from march 2003 to july 2004 the mean intensity of deep currents range between 3 5 cm s 1 at the canyon axis 1500 m and 5 4 cm s 1 upstream canyon wall 900 m a wavelet analysis shows that the energy is concentrated in the 2 30 day band and it is mainly associated to single not periodical not wave related events uncoupled at the different canyon sites an empirical orthogonal function analysis shows two main patterns of current variability explaining 65 of the total variance the first mode represents intensifications of the typical along bathymetry pattern of currents over the canyon the second mode corresponds to near bottom upwelling events along the canyon axis with water exiting the canyon through the canyon head after discussing possible forcing mechanisms it is here suggested that such deep upwelling events are associated to offshore displacements of the northern current namely the interaction of the current with the particular shape of the canyon topography at large depths 1800 m would be responsible for the observed deep upwelling events

evidence of a several day propagating wave abstract a large 8 day oscillation was recorded during several months by current meters moored at several depths and places on the continental slope off the gulf of lions in the northwestern mediterranean sea this signal is clearly associated with a propagating wave the location of the moorings the space and time scale and specific features of the signal account for a relationship between the characteristics of the wave and the mean bottom slope as supported by the results of a simple analytical model it is suggested that the bottom slope acts like a wave guide for the wave

luminescence dating indicates radiocarbon age underestimation in late pleistocene fluvial deposits from eastern england robust geochronological control is crucial for interpreting and correlating the environmental record from fragmentary terrestrial sequences from the last glacial period traditional terrestrial stratigraphies are typically reliant on radiocarbon dating although estimates of antiquity for samples older than 40 ka may be unreliable optically stimulated luminescence osl dating of sediments is an alternative for dating the whole of the last glacial period and also provides the opportunity to independently test radiocarbon based chronologies this paper presents a set of nine directly comparable paired osl and accelerator mass spectrometry ams radiocarbon ages from multiple sites within devensian fluvial sediments in lowland britain and shows that it is possible to obtain robust osl age estimates throughout this time period the two techniques agree well for ages younger than ca 29 14c ka bp ca 35 cal ka bp but disagree beyond ca 35 14c ka bp ca 40 cal ka bp this is thought to be due to radiocarbon ages on older organic material having been contaminated by low levels of modern carbon it is therefore suggested that all conventionally pre treated radiocarbon ages greater than 35 14c ka bp should be treated with extreme caution copyright 2009 john wiley sons ltd

northern current variability and its impact on the blanes canyon circulation a numerical study a high resolution 1 2 km 3d numerical model was used to analyze the interaction of the northern current a right bounded flow with the blanes submarine canyon bc nw mediterranean although it refers to a climatological simulation the model properly suites our purpose since it simulates the northern current nc mesoscale variability as well as its seasonal variability model results were validated with satellite sea surface temperature and current meter data the simulated nc tends to be faster and deeper in winter and slower and shallower in summer according to our results nc meanders and eddies are recurrent in the bc area and produce highly fluctuating three dimensional circulation patterns within the canyon we found that nc meanders and anticyclonic eddies propagating along the current pathway tend to be deep and consequently their effects extend down to the deeper part of the bc we also found that the meandering of the nc plays a key role in enhancing vertical motions inside the bc upwelling and downwelling events occurring on timescales of 4 20 days are associated with nc meanders crests and troughs passing over the bc net upwelling downwelling events are accordingly influenced by the nc seasonality they are more predominant in winter while damped in summer our results show the importance of nc meanders in creating local net upwelling downwelling and strengthen the evidence that continuous right bounded downwelling favorable flows can also produce net upwelling inside submarine canyons

the late pleistocene loess deposits and palaeosols of eastern belgium new tl age determinations fourteen samples from the pleistocene loess exposures at kesselt belgian limbourg have been dated with the thermoluminescence method using the regeneration technique and a double analysis with two types of blue transmittant filters reproducible age estimates were obtained up to about 130 140 ka for the basal part of the late weichselian brabant loess and the underlying cryorurbated nagelbeek horizon we arrived at ages of 20 22 ka which is consistent with the radiocarbon age of this horizon 22 3 ka our tl dates further constrain the formation of a lower luvisol profile the bt horizon of which has been correlated with the rocourt palaeosol to the period 50 60 ka these dates however may overstimate the true age of the sediment because they were obtained on reworked loess they indicate that this palaeosol was formed during a middle weichselian interstadial and not during the eemian as is generally accepted the boundary between the weichselian and the older loess is situated at a lower level in the kesselt profile the loess bracketing the deeper tundra gleysols yielded tl ages up to 130 140 ka and the ages further rapidly increased with depth indicating that the sediments may even be much older than saalian 1998 john wiley sons ltd

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

flora fauna and climate of scotland during the weichselian middle pleniglacial palynological macrofossil and coleopteran investigations thin lenses of organic rich material on the upper surface of a layer of glacio fluvial deposits have been studied in an open cast coal mine near sourlie western scotland radiocarbon dates on antler fragments plant debris and bulk organic matter from silt showed that the sediments accumulated between ca 33 500 and 29 000 14c yr bp during a period when this part of western scotland was free of glaciers the organic rich sediments yielded a very rich flora and fauna and in total about 160 plant taxa and 61 coleopteran taxa were recorded together with other invertebrates the sourlie flora is one of the richest late middle weichselian floras yet studied within the british isles leg bones of coelodonta antiquitatis woolly rhinoceros and rangifer tarandus reindeer were also found at the site during this period the landscape was treeless and the vegetation could be characterised as an intermediate between a low shrub tundra and sedge grass moss tundra both the flora and arthropod fauna suggest that during formation of the organic rich layers at sourlie mean july temperatures were 9 10 c the flora suggests also that at the beginning of formation of these layers minimum mean july temperatures increased from 7 to 9 10 c but later dropped again to 7 8 c a possible time correlation with one of the warmer periods of the dansgaard oeschger cycles in the stable oxygen isotope record of the greenland ice cores during this period is proposed the arthropod fauna suggests that mean january temperatures were somewhere between 34 and 11 c mean annual temperatures lay probably between 1 and 10 c which implies the possible presence of discontinuous or continuous permafrost in the area during winter a protective snow cover of varying thickness probably enabled perennial plants especially shrubs to survive

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

the last interglacial glacial cycle mis 5 2 re examined based on long proxy records from central and northern europe abstract current multi proxy studies on a long sediment sequence preserved at sokli n finland i e in the central area of fennoscandian glaciations are drastically changing classic ideas of glaciations vegetation and climate in northern europe during the late pleistocene the sediments in the sokli basin have escaped major glacial erosion due to non typical bedrock conditions in this review the sokli record is compared in great detail with other long proxy records from central temperate and northern boreal europe these comprise the classic records of la grande pile e france and oerel n germany and more recently obtained records from horoszki duze e poland and lake yamozero nw russia the focus of the review is on pollen lithology and macrofossil and insect based temperature inferences the long records are further compared with recent proxy data from nearby terrestrial sites as well as with the rapidly accumulating high resolution proxy data from the ocean realm the comparison allows a re examination of the environmental history and climate evolution of the last interglacial glacial li g cycle mis 5 2 it shows that environmental and climate conditions during mis 5 ca 130 70 ka bp were distinctly different from those during mis 4 2 ca 70 15 ka bp mis 5 is characterized by three long forested intervals broadly corresponding to mis 5e 5c 5a both in temperate and northern boreal europe these mild periods were interrupted by two short relatively cold and dry intervals mis 5d and 5b with mountain centered glaciation in fennoscandia millennial scale climate events were superimposed upon these longer lasting climate fluctuations the time interval encompassing mis 4 2 shows open vegetation it is characterized by two glacial maxima mis 4 and 2 with sub continental scale glaciation over northern europe and dry conditions in strongly continental eastern european settings high amplitude climate oscillations of millennial duration characterized the climate variability of mis 3 mild climate conditions in early mis 3 caused large scale deglaciation of the fennoscandian ice sheet and ice free conditions with betula dominated vegetation including tree birch persisted over large parts of fennoscandia possibly interrupted by glaciation during major part of mis 3 till ca 35 ka bp overall mis 5 was mostly mild with warmest or peak interglacial conditions at the very start during mis 5e mis 4 2 was mostly cold with most extreme or peak glacial conditions in the closing phase during mis 2 this points to a subdivision of the last climate cycle into an early overall mild interglacial half and a late overall cold glacial half each with duration of ca 50 ka this review also shows that the climate variability in central and northern europe during the li g cycle was mostly in degrees of continentality with major shifts in winter temperature and precipitation values summer temperatures on the other hand remained largely unchanged it points to the waxing and waning of sea ice over the north atlantic ocean as a possible characteristic feature of the late pleistocene the present compilation based on long terrestrial sequences high resolution multi proxy data from the oceans and quantified paleo climate data strongly favors a definition of entire marine oxygen isotope stage 5 as the last interglacial similar as in the original marine stratigraphy and the stratigraphy at la grande pile in france the proxy based climate data places the start of the last glacial at the base of mis 4 and the northwest european pleniglacial it shows that the division between the eemian mis 5e and the early weichselian mis 5d a is not useful as not relevant from a climate point of view

a late middle pleistocene temperate periglacial temperate sequence oxygen isotope stages 7 5e near marsworth buckinghamshire uk abstract river channel and colluvial deposits near marsworth buckinghamshire record a temperate periglacial temperate sequence during the late middle pleistocene the deposits of a lower channel contain tufa clasts bearing leaf impressions that include acer sp and sorbus aucuparia and containing temperate arboreal pollen attributed to ash dominated woodland the tufa probably formed at the mouth of a limestone spring before being redeposited in a small river whose deposits contain plant remains mollusca coleoptera ostracoda and vertebrate bones of temperate affinities the sediments sedimentary structures and limited biological remains above the lower channel deposits indicate that fluvial deposition preceded climatic cooling into periglacial conditions fluvial deposition recurred during a later temperate episode as shown by the mammalian bone assemblage in stratigraphically higher channel deposits the upper channel deposits are confidently attributed to oxygen isotope sub stage 5e ipswichian on the basis of their vertebrate remains however the age of the lower channel deposits is less clear the mammalian and coleopteran remains in the lower channel strongly suggest correlation with oxygen isotope stage 7 on the basis of their similarities to other sites whose stratigraphy is better known and the clear difference of the lower channel assemblage from well established faunas of ipswichian or any other age by contrast u th dating of the tufa clasts suggests an age post 160 ka bp while aile ile ratios on mollusca point to an ipswichian age and younger four ways of interpreting this age discrepancy are considered the preferred one correlating the lower channel deposits with oxygen isotope stage 7

a coleopteran fauna from the middle wurm weichselian of switzerland and its bearing on palaeobiogeography palaeoeclimate and palaeoecology recent exposures of the upper lignite layer from the gossau section on the swiss plateau near zurich have shown that it contains a rich fauna of fossil coleopteran remains beetles these deposits have been radiocarbon dated to 28 500 yr bp up to now the environment of the middle wurm period has not been well documented in switzerland so this exposure provides a rare opportunity to investigate the palaeobiogeography local environment and palaeoclimate of this episode a coleopteran assemblage was obtained from the upper lignite in which 30 taxa were identified of which 26 could be determined to the species level all the species are still living today though ten of them are no longer found in switzerland their modern geographical ranges are boreal or boreo montane and on the whole the fauna is typical of lower alpine or northern tundras of the present day the mcr mutual climatic range method was used here to estimate the mean temperatures of the warmest month 9 c and of the coldest months 21 c comparing these estimated palaeotemperatures with modern values from the nearest meteorological station zurich airport middle wurm mean july palaeotemperatures were about 10 c lower and mean january february palaeotemperatures were about 20 c lower than today copyright 2001 john wiley sons ltd

quaternary volcano lacustrine patterns and palaeobotanical data in southern armenia the morphogenetic evolution of the lesser caucasus has been strongly influenced by plio quaternary volcanic and tectonic events and pleistocene glaciations fluvio lacustrine environments indicated by diatomaceous deposits prevailed in the syunik region of southern armenia during the pliocene and pleistocene the pleistocene diatomaceous deposits studied contain leaf impressions and pollen allowing local palaeoclimatic reconstructions the chronology of morphogenetic events has been determined by 17 radiometric dates k ar ar ar u th palaeomagnetic investigations and is placed in a spatial context by a detailed geomorphological map and a 24 km geological transect of the vorotan valley the main area studied before 1 21 ma tectonic movements antecedents of the lower part of the vorotan valley generated extensive lake formations with diatomaceous deposits from 993 ka volcanic eruptions produced lava flows that covered the fluvio lacustrine accumulations during marine isotopic stages 12 6 and 4 glaciers and fluvio glacial deposits were probably present overall the principal uplands and valleys of southern armenia at 53 68 ka mis 3 12 6 ka 10 78 ka and 4 14 ka mis 1 the development of travertines on some slopes and in some valleys highlights temperate and humid climatic phases palaeobotanical studies of leaf and pollen floras show that the vegetation changed several times from forested to steppic phases in response to the climate oscillations of the lower pleistocene this work proposes a first morphogenic and palaeoclimatic reconstruction from the lower pleistocene to the postglacial period when the first settlements of the population in the lesser caucasus were influenced by tectono volcanic events lake level changes and glacialeinterglacial oscillations forced by the obliquity orbital parameter 41 ky cycles

osl chronology of the huksan mud belt south eastern yellow sea and its paleoenvironmental implications abstract the huksan mud belt hmb is located in the south eastern yellow sea the radiocarbon 14c and optically stimulated luminescence osl age datings of the pre holocene hmb sediments were compared precisely osl dates for the uppermost hmb sediments showed the recent and short term chronological development of the hmb osl and 14c ages of the holocene sediment hmb cores 101 103 were relatively consistent by contrast the osl ages of the pre holocene sediment unit were considerably older than the 14c ages by approximately 30 where the osl ages corresponded broadly to marine isotope stages mis 5 and 4 from about 125 ka to 50 ka an overall comparison of 14c and osl dates suggests that the age of the holocene mud unit is well constrained by 14c dating however 14c ages older than 40 ka may be unreliable the surficial sedimentation rate and depositional ages for a 6 5 m thick sequence of the uppermost unit 12hmb cores were determined twenty osl samples gave an age of approximately 8 5 ka most of the osl ages for each site were in stratigraphic order the surficial sediment ages for the 12 hmb cores were 2 6 ka for p 08 7 7 ka for p 10 7 3 ka for p 11 and 0 05 ka for p 14 the approximate surficial sediment ages of the uppermost unit of the hmb 101 102 and 103 cores were 6 7 ka 6 8 ka and 1 1 ka respectively the spatiotemporal differences in deposition and erosion of the hmb holocene muds supposedly driven by changes in large strong tidal forces and marine water depth and an increase in ocean current velocity could account for the various surficial deposition ages in the area

irregular glacial interstadials recorded in a new greenland ice core the greenland ice sheet offers the most favourable conditions in the northern hemisphere for obtaining high resolution continuous time series of climate related parameters profiles of 18o 16o ratio along three previous deep greenland ice cores1 3 seemed to reveal irregular but well defined episodes of relatively mild climate conditions interstadials during the mid and late parts of the last glaciation but there has been some doubt as to whether the shifts in oxygen isotope ratio were genuine representations of changes in climate rather than artefacts due to disturbed stratification here we present results from a new deep ice core drilled at the summit of the greenland ice sheet where the depositional environ ment and the flow pattern of the ice are close to ideal for core recovery and analysis the results reproduce the previous findings to such a degree that the existence of the interstadial episodes can no longer be in doubt according to a preliminary timescale based on stratigraphic studies the interstadials lasted from 500 to 2 000 years and their irregular occurrence suggests complexity in the behaviour of the north atlantic ocean circulation

the construction of a palaeodischarge time series for use in a study of fluvial system development of the middle to late pleistocene upper thames recently many studies have attempted to model fluvial system development over a variety of geographical and temporal scales it is generally recognised that one of the main problems especially in studies over longer timescales 100 ka is the reconstruction of a robust palaeodischarge time series over such extended timescales discharge can only be reconstructed using proxy data i e either field based sediment palaeodischarge estimates or transformation of reconstructed palaeoclimate data series e g ice core data with only the latter method allowing the reconstruction of a continuous time series in this study of the upper thames catchment uk we have developed a new palaeodischarge time series a sea surface temperature record odp 980 from the north atlantic off the west coast of ireland is used as a proxy for precipitation across the upper thames catchment a vegetation filter based on pollen data is then applied to this precipitation record in order to create a runoff model finally this runoff model is transformed to a discharge model via the use of a climate change function which attempts to reflect probable changes in the frequency and magnitude of discharge events using our new palaeodischarge model we present output from the fluver2 model of longitudinal profile development for the middle to late pleistocene upper thames valley this model simulates the possible timing and magnitude of sediment aggradation degradation events on the floodplain as well as the timing of floodplain abandonment due to tectonic uplift resulting in terrace formation copyright 2010 john wiley sons ltd

late quaternary climate change in the awatere valley south island new zealand using a sine model with a maximum likelihood envelope on fossil beetle data we present a new climatic reconstruction method appropriate for biological proxies where modern distributions are poorly defined and data sets are small the technique uses a sine function in conjunction with maximum likelihood estimates of best high and best low values for the distribution of each species to demonstrate the model we present temperature reconstructions for the last glacial maximum lgm and holocene from beetle fossil assemblages from the awatere valley new zealand the temperature estimates are determined by the mutual overlap of the climate range for all the species in the assemblage the overlap is then compared with modern physio chemical conditions for our example we estimate the lgm summer february mean temperature was about 3 5 4degreesc cooler and july winter mean daily minimum temperature was about 4 5degreesc cooler than present day temperatures the maximum likelihood estimates broaden the reconstructed temperature ranges to 2 5 5degreesc cooler for february temperatures and 3 5 6 0degreesc cooler for mean minimum daily temperature of the coldest month july these estimates are consistent with lgm temperature estimates of 4 7degreesc from other climate proxy indicators estimates of holocene temperatures are very similar to modern estimates are compared with results from the established mutual climatic range mcr technique and the results are compatible mcr is less robust than the sine model approach for these data because it requires the pre determination of the critical physiochemical controls and assumes gaussian distributions in climate space the sine model is conceptually superior to traditional bioclim modelling with which it shares many features because bioclim also assumes gaussian distributions and the sine model allows attribute testing of the data sets which are not possible with bioclim c 2004 elsevier ltd all rights reserved

european vegetation during marine oxygen isotope stage 3 european vegetation during representative warm and cold intervals of stage 3 was inferred from pollen analytical data the inferred vegetation differs in character and spatial pattern from that of both fully glacial and fully interglacial conditions and exhibits contrasts between warm and cold intervals consistent with other evidence for stage 3 palaeoenvironmental fluctuations european vegetation thus appears to have been an integral component of millennial environmental fluctuations during stage 3 vegetation responded to this scale of environmental change and through feedback mechanisms may have had effects upon the environment the pollen inferred vegetation was compared with vegetation simulated using the biome 3 5 vegetation model for climatic conditions simulated using a regional climate model regcm2 nested within a coupled global climate and vegetation model genesis biome despite some discrepancies in detail both approaches capture the principal features of the present vegetation of europe the simulated vegetation for stage 3 differs markedly from that inferred from pollen analytical data implying substantial discrepancy between the simulated climate and that actually prevailing sensitivity analyses indicate that the simulated climate is too warm and probably has too short a winter season these discrepancies may reflect incorrect specification of sea surface temperature or sea ice conditions and may be exacerbated by vegetation climate feedback in the coupled global model

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

evidence for general instability of past climate from a 250 kyr ice core record recent results1 2 from two ice cores drilled in central greenland have revealed large abrupt climate changes of at least regional extent during the late stages of the last glaciation suggesting that climate in the north atlantic region is able to reorganize itself rapidly perhaps even within a few decades here we present a detailed stable isotope record for the full length of the greenland ice core project summit ice core extending over the past 250 kyr according to a calculated timescale we find that climate instability was not confined to the last glaciation but appears also to have been marked during the last interglacial as explored more fully in a companion paper3 and during the previous saale holstein glacial cycle this is in contrast with the extreme stability of the holocene suggesting that recent climate stability may be the exception rather than the rule the last interglacial seems to have lasted longer than is implied by the deep sea specmap record4 in agreement with other land based observations5 6 we suggest that climate instability in the early part of the last interglacial may have delayed the melting of the saalean ice sheets in america and eurasia perhaps accounting for this discrepancy

changes in the thermal climate in northwestern europe during marine oxygen isotope stage 3 estimated from fossil insect assemblages abstract more than 30 fossil coleopteran beetle assemblages have been recorded from oxygen isotope stage 3 in northern europe comprising several hundred identified species using the mutual climatic range method for quantifying palaeotemperatures these assemblages show that the climates of the times can be divided into two distinct interstadial types one a short phase of temperate oceanic climate occurred between 43 000 and 42 000 14c yr b p when conditions were not much different from those of the present day in spite of the temperate climate trees did not colonize northwestern europe at this time two both before and after this temperate interlude there were phases of cold continental climate during which summers were too cold for trees to grow and winters were of siberian intensity it is possible that periods of even colder conditions intervened from time to time between the interstadial but because of the intensity of the cold biological systems were so inhibited that no fossil evidence for them can be found in northern europe evidence for them must be sought in the fossil records from the warmer parts of southern europe or in the physical evidence in the greenland ice cores

land sea correlations in the pleistocene based on isoleucine epimerization in non marine molluscs the correlation between the oxygen isotope stratigraphy of the oceans and continental stratigraphic records is one of the main challenges for quaternary research most continental classifications however are based on techniques and hypotheses that predate recent advances nevertheless the deep sea oxygen isotope global stratigraphic framework has been extended to the continents by means of some long sequences1 but these are exceptional and regional geology is unsatisfactorily classified for correlation with the oxygen isotope signal because successive geological events produced similar evidence homotaxis geochronometric dating is essential for correlation but available methods are highly site regional or sample specific fortunately non marine molluscs are ubiquitous in time and space and here we use the time dependent epimerization of l isoleucine in these fossils to subdivide the pleistocene of the british isles and to identify more events than recognized by the existing classification2 by calibrating the relative aminostratigraphic scale with independent dating methods we have set up a geochronology which is the basis for land sea correlations back to oxygen isotope stage 15

climatic control on quaternary fluvial sedimentology of a fenland basin river england understanding and interpreting climate response from ancient fluvial deposits requires a combined approach of detailed sedimentological description and interpretation local climate proxies and the accurate comparison of these sequences with further independent climate records application of these multiple lines of evidence is particularly effective in the quaternary period where higher resolution and more detailed palaeoenvironmental reconstruction are possible this paper presents results from a devensian weichselian age sequence in northern fenland england that integrates these approaches detailed sedimentological description has identified three fluvial facies associations overlain by a period of ice wedge cast formation fossil plant and coleopteran material within these sediments have been studied to provide palaeoenvironmental reconstructions for the local landscape including quantitative temperature estimates using the mutual climatic range method on fossil coleoptera in addition joint application of radiocarbon and optically stimulated luminescence osl dating allows this sequence to be compared with the stacked marine isotope record although dates do not agree well at the limit of the radiocarbon technique sedimentological interpretations palaeoenvironments and global ice volume variations a proxy for climatic severity are all in agreement and show clearly how the river nene responded to subtle changes in climate and vegetation cover during the devensian weichselian stage the level of detail possible in this reconstruction shows the importance of this approach in understanding fluvial response to past climate changes

limits to resolving catastrophic events in the quaternary fluvial record a case study from the nene valley northamptonshire uk flood events within rivers are responsible for much erosion and deposition thus deposits laid down during floods could potentially comprise the bulk of the quaternary fluvial record however it is difficult to detect individual flood events as effectively illustrated by the middle devensian weichselian to holocene fluvial sequence from the nene valley northamptonshire described in this paper this is due to limits in the resolution of sedimentological palaeontological and geochronological techniques geochronological techniques have the highest resolution but error bars of c 50 years radiocarbon and up to 2 ka optically stimulated luminescence in the late glacial do not allow detection of floods lasting only a few weeks or less geochronology is however essential for linking periods of fluvial deposition to climatic phases at the marine isotope substage scale thus multiple age determinations show remnant middle devensian deposits within a facies association mainly of younger dryas age showing similar fluvial response to climate during both time periods palaeontological assemblages suggest that climate was also similar although with some subtle differences determining average fluvial activity in response to broad climate phases improves understanding of how rivers behave over long time periods even though determination of the role of flood events in the quaternary fluvial record remains elusive

heat flow pattern at the chicxulub impact crater northern yucatan mexico abstract along an east west profile crossing the chicxulub impact structure in northern yucatan mexico curie depths were obtained from statistical spectral analysis of a grid of aeromagnetic data 256 km wide and 600 km long these depths were corrected for flight height and depth to the sea floor to determine the geothermal gradient assuming a temperature of 580 c for the curie temperature heat flow was then calculated from the geothermal gradients using a value of 2 67 w m k for the mean crustal thermal conductivity the results show a conspicuous heat flow high above on the impact basin in this location the heat flow is 80 mw m 2 approximately available offshore estimates of the depth to the crustal magnetic source bases on the northern yucatan platform and onshore heat flow determination on 8 shallow bore holes and in a 1511 m deep one support the existence of this major high heat flow anomaly associated with the impact crater this high heat flow might be related to the impact through 1 an uplift of the crystalline basement rocks in the center of the crater and 2 impact induced radioactive element concentration into the crust below the impact structure higher thermal conductivities at the lower crust might also play a key role available seismological and thermal property data are compatible with these mechanisms