climate instability during the last interglacial period recorded in the grip ice core isotope and chemical analyses of the grip ice core from summit central greenland reveal that climate in greenland during the last interglacial period was characterized by a series of severe cold periods which began extremely rapidly and lasted from decades to centuries as the last interglacial seems to have been slightly warmer than the present one its unstable climate raises questions about the effects of future global warming

absolute calibration of the greenland time scale implications for antarctic time scales and for δ14c abstract we propose a new age scale for the two ice cores grip and gisp2 that were drilled at greenland summit based on accelerator mass spectrometry 14c dating of foraminifera in core md95 2042 paleoceanography 15 2000 565 calibrated by means of recently obtained paired 14c and 230th measurements on pristine corals marine radiocarbon calibration curve spanning 10 500 to 50 000 years bp thousand years before present based on paired 230th 234u 238u and 14c dates on pristine corals geological society of america bulletin 2003 submitted for publication the record of core md95 2042 can be correlated very precisely to the greenland ice cores between 30 and 40 ka bp our scale is 1 4 ka older than the grip ss09sea time scale journal of quaternary science 16 2001 299 at the older end of marine isotope stage 3 we use published 230th dates from speleothems to calibrate the record using this scale we show a 14c record that is broadly consistent with the modelled record earth planet sci lett 200 2002 177 and with the data of hughen et al science 303 2004 202 but not consistent with the high values obtained by beck et al science 292 2001 2453 or by voelker et al radiocarbon 40 1998 517 we show how a set of age scales for the antarctic ice cores can be derived that are both fully consistent with the greenland scale and glaciologically reasonable

when did hominids first leave africa new high resolution magnetostratigraphy from the erk el ahmar formation israel new paleomagnetic results from the erk el ahmar formation israel resolve age ambiguities of one of the oldest hominid sites outside africa where ancient oldowan tools and artifacts were excavated we identified in the section the upper and lower boundaries of the olduvai subchron and we conclude that these sediments were deposited between ca 1 7 and 2 0 ma this result is consistent with the hypothesis that earliest hominid migrations from africa to eurasia during the early paleolithic traversed the levantine corridor

revised magnetostratigraphy of the plio pleistocene sedimentary sequence of the olduvai formation tanzania abstract the magnetic stratigraphy of the plio pleistocene sedimentary formation of the olduvai gorge tanzania which contains a well known series of prehistoric pebble cultures and hominid remains has been reinvestigated sixty one sites were sampled along 90 metres of stratigraphic section extending from the base of bed i into the masek beds palaeo and rock magnetic analyses reveal that magnetizations are stable carried by low coercivity magnetic minerals titano magnetites and are likely to be of depositional origin a revised magnetostratigraphic scale is proposed the base of the major normal magnetozone n1 interpreted as the olduvai sub chron lies ca 6 m below tuff ia i e significantly below the previously defined position this revision associated to 40ar 39ar ages recently determined on the tuffs of bed i supports the validity of the astronomical calibration of the geomagnetic polarity time scale for the olduvai sub chron the correlation of the normal magnetozone n2 with jaramillo or jaramillo cobb mountain is suggested by the discovery of a reverse magnetozone r3 in the uppermost part of the pleistocene sequence masek beds and implies that the fossiliferous sequence of the olduvai formation was entirely deposited before the brunhes matuyama boundary

the estuarine geochemical reactivity of zn isotopes and its relevance for the biomonitoring of anthropogenic zn and cd contaminations from metallurgical activities example of the gironde fluvial estuarine system france abstract zinc stable isotopes measurements by mc icp ms validated by laboratory intercalibrations were performed on wild oysters suspended particles and filtered river estuarine water samples to provide new constraints for the use of zn isotopes as environmental tracers the samples selected were representative of the long range 400 km transport of metal zn cd etc contamination from former zn refining activities at decazeville i e 66 zn 1 and its phasing out recorded during 30 years in wild oysters from the gironde estuary mouth rno rocch sample bank the study also addresses additional anthropogenic sources urban and viticulture and focuses on geochemical reactivity of zn in the turbidity gradient and the maximum turbidity zone mtz of the fluvial gironde estuary in this area dissolved zn showed a strong removal onto suspended particulate matter spm and progressive enrichment in heavy isotopes with increasing spm concentrations varying from 66 zn 0 02 at 2 mg l to 0 90 at 1310 mg l these signatures were attributed to kinetically driven adsorption due to strongly increasing sorption sites in the turbidity gradient and mtz of the estuary oysters from the estuary mouth contaminated sediments from the lot river and spm entering the estuary showed parallel historical evolutions 1979 2010 for zn cd ratios but not for 66 zn values oysters had signatures varying from 66 zn 1 43 in 1983 to 1 18 in 2010 and were offset by 66 zn 0 6 0 7 compared to past 1988 and present spm from the salinity gradient isotopic signatures in river borne particles entering the gironde estuary under contrasting freshwater discharge regimes during 2003 2011 showed similar values 66 zn 0 35 0 03 1sd n 15 i e they were neither related to former metal refining activities at least for the past decade nor clearly affected by other anthropogenic sources therefore the zn isotopic signatures in gironde oysters reflect the geochemical reactivity of zn in the estuary rather than signatures of past metallurgical contaminations in the watershed as recorded in contaminated river sediments the study also shows that the isotopic composition of zn is strongly fractionated by its geochemical reactivity in the gironde estuary representative of meso macrotidal estuarine systems

the sima de los huesos hominids date to beyond u th equilibrium 350 kyr and perhaps to 400 500 kyr new radiometric dates the sima de los huesos site of the atapuerca complex near burgos spain contains the skeletal remains of at least 28 individuals in a mud breccia underlying an accumulation of the middle pleistocene cave bear u deningeri earlier dating estimates of 200 to 320 kyr were based on u series and esr methods applied to bones made inaccurate by unquantifiable uranium cycling we report here on a new discovery within the sima de los huesos of human bones stratigraphically underlying an in situ speleothem u series analyses of the speleothem shows the lower part to be at isotopic u th equilibrium translating to a firm lower limit of 350 kyr for the sh hominids finite dates on the upper part suggest a speleothem growth rate of c 1 cm 32 kyr this rate along with paleontological constraints place the likely age of the hominids in the interval of 400 to 600 kyr

dating the earliest lowland glaciation of eastern england a pre mis 12 early middle pleistocene happisburgh glaciation this paper outlines the evidence for the happisburgh glaciation the first middle pleistocene glaciation of lowland eastern england and the adjacent margins of the north sea basin we propose that this glaciation occurred during a pre elsterian anglian mis 12 cold stage based on evidence of clasts of till erratics and heavy minerals from the third youngest terrace of the pre glacial bytham river in southern norfolk the heavy minerals show a progressive increase in glacially sourced materials from the bottom to the top of the bytham river third terrace sediments the till clasts are correlated with the extensive deposits of the happisburgh formation on the basis of their colour heavy minerals and particle size properties thus the happisburgh glaciation occurred during the accumulation of the bytham river terrace deposits and prior to mis 12 when the bytham river system was destroyed by the anglian glaciation in the absence of any geochronology or robust biostratigraphy the age of the happisburgh glaciation is estimated by the synchronisation of the pattern of large scale river activity with patterns of milankovitch forced global climate change on this basis and assuming the british ice sheet acted in phase with global patterns of ice volume the happisburgh glaciation is considered to have occurred during mis 16 and be equivalent of the don glaciation of eastern europe

early diagenesis of trace metals cd cu co ni u mo and v in the freshwater reaches of a macrotidal estuary vertical profiles from the water column including the maximum turbidity zone mtz to the consolidated sediment were sampled in september 2000 in the freshwater reaches of the gironde estuary during a complete neap tide spring tide cycle the vertical distributions of dissolved major redox parameters and metals mn fe cd cu v co ni mo and u were determined reactive particulate metal fractions were also determined from selective leaching the studied system is characterized by density layers functioning at different time scales consisting of two mobile layers i e the liquid lm and the soft mud sm overlying consolidated sediments cs this results in a three zone diagenetic regime where 1 o2 dynamics are fast enough to show depletion in the rapidly mixed lm sequence tidal time scale 2 denitrification occurs on the weekly time scale mixing sm sequence and 3 the mn fe and sulfate cycling occurs in the cs layer annual time scale the studied trace metals show differential behavior during early diagenesis 1 cd cu and v are released into pore water preferentially from organic matter in the sm 2 co ni and u are released in the cs from mn and fe oxides during reductive dissolution and 3 mo from both processes transient conditions i e oscillations of redox fronts and reoxidation processes due to the dynamics of the mobile layers strongly influence the trace metal distributions as inducing resolubilization cd cu and mo in the cs authigenic metal phases accumulate either by direct precipitation with sulfides cu cd or co precipitation with fe sulfides mo microbially mediated reduction of fe oxides is proposed to control u removal from pore water by reduction of u vi to u iv at depth however a significant fraction of the trace metals is trapped in the sediment in exchangeable forms and therefore is susceptible to be mobilized due to resuspension of estuarine sediment during strong river flood periods and or dredging activities

eight glacial cycles from an antarctic ice core the antarctic vostok ice core provided compelling evidence of the nature of climate and of climate feedbacks over the past 420 000 years marine records suggest that the amplitude of climate variability was smaller before that time but such records are often poorly resolved moreover it is not possible to infer the abundance of greenhouse gases in the atmosphere from marine records here we report the recovery of a deep ice core from dome c antarctica that provides a climate record for the past 740 000 years for the four most recent glacial cycles the data agree well with the record from vostok the earlier period between 740 000 and 430 000 years ago was characterized by less pronounced warmth in interglacial periods in antarctica but a higher proportion of each cycle was spent in the warm mode the transition from glacial to interglacial conditions about 430 000 years ago termination v resembles the transition into the present interglacial period in terms of the magnitude of change in temperatures and greenhouse gases but there are significant differences in the patterns of change the interglacial stage following termination v was exceptionally long 28 000 years compared to for example the 12 000 years recorded so far in the present interglacial period given the similarities between this earlier warm period and today our results may imply that without human intervention a climate similar to the present one would extend well into the future

the biface assemblage from gesher benot ya aqov israel illuminating patterns in out of africa dispersal abstract this article presents the main characteristics of a lithic assemblage in particular its biface component from the acheulean site of gesher benot ya aqov israel we endeavor to demonstrate that this tradition did not evolve locally within the levant but was rather a result of a diffusion of ideas and or population from africa into the levant during the end of the lower beginning of the middle pleistocene the fact that other acheulean industries present in the northern dead sea rift resemble corresponding african traditions rather than each other may indicate that the gesher benot ya aqov occurrence was not an isolated event this phenomenon may be interpreted as representing a dynamic system in which populations and or ideas dispersed out of africa during the lower and middle pleistocene in repetitive distinct and separate waves

hominin responses to pleistocene environmental change in arabia and south asia palaeoanthropologists typically outline human evolution within a framework of pleistocene environmental change environmental change occurring across the early middle pleistocene transition is examined relative to patterns of hominin dispersal ecological adaptations cognitive advances and behavioural flexibility although climatic information has been used as the backdrop to human evolution major lacunae exist in our understanding of the ecological settings where hominins evolved data from investigations conducted in the arabian peninsula and the indian subcontinent are reviewed indicating the nature of palaeolithic localities and their physical settings although much information remains to be obtained from these terrestrial records significant changes are recognized in the environmental and archaeological record the early middle pleistocene transition shows some conservative trends in hominin adaptations and technology yet it is also an interval that evidences an increasing ability to transcend environmental controls through a greater level of behavioural flexibility and innovation

the copper isotope geochemistry of rivers and the oceans abstract we present the first extensive dataset for copper cu isotopes in rivers as well as preliminary data for estuaries and seawater rivers exhibit a range in dissolved 65 cu relative to nist srm 976 of 0 02 to 1 45 per mil the discharge weighted average dissolved 65 cu and cu concentration for the studied rivers representing around 25 of the global riverine water discharge are 0 68 and 18 8 nmol kg 1 respectively isotopic data for the dissolved phase in two small estuaries in se england exhibit relatively minor variation through the salinity gradient 0 42 to 0 94 and are close to both the data for the rivers upstream from the estuaries and a measurement of the coastal sea at their mouths analyses of the particulate phase in the estuaries reveal a complementary light pool 0 24 to 1 02 the isotopic composition of the total cu inventory is however close to that of the crustal source these data along with published constraints suggest that the isotopically heavy dissolved phase of all the rivers originates in an isotopic partitioning of the weathered pool of cu between a light fraction adsorbed to particulates and a heavy dissolved fraction dominated by cu bound to strong organic complexes open ocean seawater samples generally exhibit even heavier dissolved cu isotopic compositions than the riverine input 65 cu 0 9 to 1 5 the heavy isotopic composition of seawater is inferred to originate from intra oceanic processes the small dataset presented here is most consistent with further isotopic partitioning between an isotopically light pool adsorbed to particulates and a heavy dissolved pool strongly bound to organic ligands scavenging appears to have greatest impact in the surface ocean and least in both the oxygen minimum zone and the ocean bottom perhaps reflecting the relative importance of scavenging and thus the sequestration of light cu to particulate material at different depths

anthropogenic sources and biogeochemical reactivity of particulate and dissolved cu isotopes in the turbidity gradient of the garonne river france abstract high precision mc icp ms cu isotope measurements were performed on suspended particulate matter spm and filtered water sampled along the turbidity gradient of the fluvial gironde estuary garonne branch following a summer lasting period of low freshwater discharge high cu concentrations up to 200 g g in particulate organic carbon poc rich up to 14 particles upstream from the maximum turbidity zone mtz coincide with the most negative 65 cu values down to 0 39 this suggests the preferential uptake of light cu isotopes by phytoplankton or anthropogenic contamination from cuso 4 fungicides related to intensive wine farming in the area 65 cu 0 37 for vineyard soils suspended particulate matter samples in the mtz exhibit lower cu concentrations 35 g g and heavier isotopic compositions 65 cu 0 20 in average as recorded by other samples from the gironde watershed along the fluvial estuary dissolved cu is mostly enriched in heavy isotopes up to 65 cu 0 21 but negative signatures down to 65 cu 0 66 occur near the city of bordeaux release of dissolved cu was attributed to the mineralization of organic matter with a total addition of 600 ng l in the fluvial estuary continuously decreasing amounts of dissolved cu added with distance suggest that the observed cu release evolved towards completion in the mtz and contributed to negative values for dissolved cu isotopes as modeled by a rayleigh process urban wastewater effluents probably also contribute to both i the dissolved cu addition 10 20 in the mtz and ii negative cu isotope signatures further work is necessary to assess the respective roles of anthropogenic sources and biogeochemical fractionation processes accordingly the present study provides new insights into the potential of cu isotopes for fingerprinting sources and mechanisms involved in the biogeochemical cycle of cu in temperate aquatic environments impacted by anthropogenic activities

africa and iberia in the pleistocene abstract the strait of gibraltar would logically seem to be a major point of contact between africa and europe yet controversy about possible trans gibraltar human movements in the lower middle and even upper pleistocene has reigned for over a century and continues to do so imbricated with biogeographical arguments about faunal transfers and the creation of hominid niches in iberia the problem of the relationships between africa and iberia is one of the knottiest in stone age prehistory did early homo h ergaster erectus or antecessor cross into iberia from the maghreb as has long been argued on the basis of general archeological similarities this old hypothesis still unproven is made somewhat more plausible by the re dating of the site of ain hanech in algeria and in particular by the spectacular lower pleistocene fossil and artifactual discoveries at atapuerca in north central spain and less securely in the guadix baza basin of granada middle pleistocene contacts remain problematic with direct peopling of iberia from northwest africa during the mid upper pleistocene seeming ironically to be out of the question as southern spain and portugal were one of the last refugia of neanderthals using mousterian technology despite proximity to the putative source of anatomical modernity and cultural superiority similarly despite years of speculation on a migrationist cause for the similarity between tanged points in the aterian of north africa and in the solutrean of mediterranean spain and portugal the chronological and archeological data solidly disprove this seductive hypothesis for the upper pleistocene it is only in the terminal paleolithic that with clear evidence of marine fishing and probable navigation a credible case can be made for trans gibraltar human contacts

orbital forcing of climate over south africa a 200 000 year rainfall record from the pretoria saltpan late pleistocene variations in rainfall in subtropical southern african are estimated from sediments preserved in the pretoria saltpan a 200000 year old closed basin crater lake on the interior plateau of south africa we show that south african summer rainfall covaried with changes in southern hemisphere summer insolation resulting from orbital precession as predicted by orbital precession geometry berger 1978 this south african record is out of phase with north african palaeomonsoon indices street and grove 1979 rossignol strick 1983 mcintyre et al 1989 the amplitude of the rainfall response to insolation forcing agrees with climate model estimates prell and kutzbach 1987 these results document the importance of direct orbital insolation forcing on both subtropical north and south african climate as well as the predicted antiphase sensitivity to precessional insolation forcing

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

copper isotope fractionation during excretion from a phototrophic biofilm abstract the metal excretion and metal sorption are two important microbial processes in the regulation of intracellular metal concentration however the contribution of freshwater phototrophic biofilm to metal efflux in the environment and its related isotopic fractionation remain poorly known in this study cu efflux from a mature phototrophic biofilm and related cu isotopic fractionation between the biofilm and aqueous solution were studied over 4 days in closed batch and open drip flow reactors br and dfr respectively the impact of a 48 h drying event on cu efflux from the biofilm and its isotopic signature was quantified in the br cu excretion from the biofilm depended on cu concentration in the biomass and did not show a latent phase for the wet biofilm in dfr the cu efflux rate decreased over time whereas in br cu efflux exhibited fluctuations with a net re sorption phase during short term early excretion over the first 4 h br and 24 h dfr the enrichment of solution in heavy isotopes with a 65cu sol biofilm of 0 7 0 2 could be explained by a combination of i desorption via competition between h and cu2 for surface sites and ii release of isotopically heavy cu ii organic complexes in addition there was a retention of isotopically light cu i within the cells which is consistent with the biofilm ability to reduce cu with further exposure of the wet biofilm to the solution a progressive decrease of 65cu sol biofilm down to 0 and 0 36 respectively in br and dfr after 96 h could be explained by an active efflux of cu i and by a passive diffusion of cu2 both of these processes favoring light isotopes the re hydrated and wet biofilms showed distinctly different behavior during excretion in terms of magnitude of the flux and direction of the fractionation for long term exposure indeed the efflux from the re hydrated biofilm was ten times higher than the one from the wet biofilm and the re hydrated biofilm did not exhibit a decrease of 65cu sol biofilm after 24 h of reaction this could be related to partial devitalization of the biofilm during drying producing a release of isotopically heavy cu and decreasing the intensity of cu i active efflux of light isotopes taken together the cu isotopic signature in natural aquatic environments containing phototrophic biofilms varies up to 1 on a daily scale

early italy and the colonization of western europe abstract the early phases of human occupation in italy are considered in the context of discussions on the chronology and patterns of hominid dispersal out of africa and into western europe this paper is therefore a synthesis and an evaluation of new data on three interrelated topics a the question of direct contacts between italy and north africa in the lower and middle pleistocene through the sicilian channel b the evidence for the successive dispersal in western europe of two different technical traditions and c the nature and chronology of the earliest human occupation of italy interpretations of bifaces and biface industries are discussed as they are an important aspect of out of africa models hominid presence in italy is documented at the beginning of the middle pleistocene their route of entry apparently not through sicily but from the north in contrast to the ubeidiya and gesher benot ya aqov assemblages in israel the earliest dated biface assemblages in italy with a preliminary date at about 640 70 ka show no specific characteristics that would tie them to the african acheulean evidence for a precedence of core and flake over handaxe industries is ambiguous their interpretation as designating different groups of hominids lacks a sound archaeological basis since faunal exchanges with continental europe are documented throughout the pleistocene the hypothesis of multiple episodes of human migration into italy should be considered however we can neither support it or refute it because the archaeological assemblages do not inform us on specific migration events

high resolution paleoclimatic information from chinese eolian sediments based on grayscale intensity profiles abstract grayscale intensity profiles from photographic images offer a rapid means of obtaining paleoclimate proxy records from chinese loess dune sand and paleosols although the data can be obtained using conventional 35 mm film images a digital camera and laptop computer will produce a high resolution grayscale profile at a field site within minutes comparison of grayscale profiles with profiles of magnetic susceptibility measured down loess and dune sand sections at sites on the loess plateau and tibetan plateau in a range of altitudes and climatic regimes shows that the two parameters are highly correlated therefore grayscale intensity is a convenient alternative to magnetic susceptibility for generating paleoclimatic data in the loess and desert margin regions of china the resolution of both grayscale and susceptibility profiles ultimately is limited by bioturbation which is most pronounced in paleosols

abundance of zinc isotopes as a marine biogeochemical tracer 1 the zn isotopic compositions of ferromanganese nodules sediment trap samples sediments and organic reference samples have been analyzed by multiple collector inductively coupled plasma mass spectrometry icp ms the range of isotopic variations 1 for 66zn 64zn is significant with respect to the analytical precision 0 04 at the 95 confidence level marine argillaceous sediments show rather constant values consistent with those of continental shales and loess and with the value of a basalt from reunion island we infer that the depletion of the light zn isotopes in marine particles and in ferromanganese nodules presumably equilibrated with seawater results from biological activity in the upper water column the 66zn values of sediment trap samples collected near the upwelling off the coast of mauritania central atlantic show a seasonal isotopic fluctuation consistent with biological pumping during the high productivity period higher values of 66zn in nodules appear to be associated with the amplitude of seasonal variations rather than with the mean values of the biological productivity

an isotopic study of paleosol carbonates from olduvai gorge the isotopic composition of paleosol carbonates from olduvai gorge can be used to give estimates of the paleoclimatic history of east africa during the plio pleistocene oxygen isotopes are indicative of major changes in the isotopic composition of meteoric water while carbon isotopes are indicative of major changes in the fraction of biomass using the hatch slack c4 photosynthetic pathway three major periods of climatic change in this terrestrial setting occurred at about 1 67 1 3 and 0 6 myr these involved major changes in flora as well as major changes in the isotopic composition of meteoric water overall the climate has become warmer and more arid over the past 2 2 myr

stratigraphy sedimentology and archaeology of middle pleistocene localities near ceprano campogrande area italy decades of fieldwork in the frosinone ceprano basin latin valley latium central italy have shed light on numerous open air lower palaeolithic localities delivering a human fossil calvarium thousands of scattered faunal remains and a large collection of lithic industries including core and flake type lithic series mode 1 and acheulean assemblages mode 2 the continuously growing number of available geochronological data obtained by 40ar 39ar on volcanic minerals esr u series on large mammal teeth and esr on bleached fluvial quartz allow today the construction of a reliable and precise chronological framework for the lower palaeolithic sites of this area of the latin valley the archaeological horizons with bifaces all appear to belong to a relatively short middle pleistocene time range between about 410 and 350 ka coeval to the end of the interglacial mis 11 and to the beginning of the following glacial mis 10 the acheulean tools are often associated with cores and flakes bifaces are mainly made on limestone secondary flint and quartz the archaeological corpus also yielded tools on fragments of large herbivore bones comparisons between technological strategies and paleo anthropological data at the global scale are now meaningful and enable us to decipher hominin behaviour at a more regional scale such careful work is becoming essential in the frame of the recent discoveries showing that the mis 11 10 period was a pivotal period characterized by the appearance of several new archaeological features later associated with the neanderthal lineage in western europe we present here the first in depth technological study of the acheulean lithic corpus from the major archaeological sites from the frosinone ceprano basin including the campogrande localities cg9 and cg10 intermediate and upper levels colle avarone selvotta isoletta level 4 lademagne upper and lower levels and masseria castellone

stable climatic conditions in central germany during the last interglacial stable isotopic data from the high resolution limnic sequence in the opencast mine at grobern central germany confirm the relatively stable climate of the last interglacial deduced from pollen analyses after significant warming during the transition from the saalian to the eemian stable warm climatic conditions set in once the climatic optimum was reached in the course of biozones e4 to e5 from the middle of biozone e6b a gradual temperature decrease can be observed reaching a minimum at the start of biozone e7 the division of the early weichselian glacial in central germany into two stadials herning rederstall and two interstadials brorup odderade is also documented by the findings copyright 2000 john wiley sons ltd

diagenesis and anchimetamorphism in an overthrust belt external domain of the taconian orogen southern canadian applachians ii paleogeothermal gradients derived from maturation of different types of organic matter abstract 3hermal maturation patterns have been established for the external domain of taconian orogen of the southern quebec appalachians between quebec city and the u s border reflectance of three types of organic matter om measured in the same sample shows that graptolite reflectance r g is higher than pyrobitumen reflectance r b which in turn is higher than reflectance of amorphous organic matter r a r g r b and r a are converted to vitrinite equivalent reflectance from which maximum paleotemperatures were calculated inverted diagenesis is preserved in northwest part of the chaudiere nappe to the southeast original burial diagenetic grade was upgraded by later synorogenic heating in the st lawrence lowlands paleogeothermal gradients at maximum burial were 33 37 c km a gradual southwestward increase in maturation level suggests increasing post taconian burial depth from 4 6 to 6 7 km indicating an increasing thickness of eroded rocks from northeast to southwest along logan s line one of the most important contributions of this study is the proof that the acadian orogeny has affected the successor basin of the taconian orogeny in the st lawrence lowlands the thermal effect of the mid cretaceous intrusion of the monteregian hills on their country rocks is limited to one diameter or less of the intrusive body as shown by the narrow

paleoclimate climate change across the hemispheres climate records from greenland ice cores have shown that climate has changed rapidly and drastically throughout the last glacial period on a millennial time scale in his perspective shackleton highlights the report by blunier and brook who have correlated the greenland records with an antarctic record there is a systematic difference in the character and timing of temperature changes in the two hemispheres although the mechanism linking the hemispheres remains uncertain absolute dating is essential

the faunal remains from evron quarry in relation to other lower paleolithic hominid sites in the southern levant abstract the mammalian assemblage and archaeological finds from the lower palaeolithic hominid site of evron quarry situated on the northern coastal plain of israel are described and discussed in their lithic and faunal composition the sites of latamne qfiii latamne formation orontes syria and sitt markho nahr elkebir syria resemble evron and are probably contemporaneous it is suggested here based on their lithic and faunal composition that these sites may be chronologically closer to the site of ubeidiya ubeidiya formation jordan valley israel 1 4 myr than to the sites of gesher benot ya akov dated as

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

precise dating of dansgaard oeschger climate oscillations in western europe from stalagmite data the signature of dansgaard oeschger events millennial scale abrupt climate oscillations during the last glacial period is well established in ice cores and marine records but the effects of such events in continental settings are not as clear and their absolute chronology is uncertain beyond the limit of 14 c dating and annual layer counting for marine records and ice cores respectively here we present carbon and oxygen isotope records from a stalagmite collected in southwest france which have been precisely dated using 234u 230th ratios we find rapid climate oscillations coincident with the established dansgaard oeschger events between 83 000 and 32 000 years ago in both isotope records the oxygen isotope signature is similar to a record from soreq cave israel and deep sea records indicating the large spatial scale of the climate oscillations the signal in the carbon isotopes gives evidence of drastic and rapid vegetation changes in western europe an important site in human cultural evolution we also find evidence for a long phase of extremely cold climate in southwest france between 61 2 0 6 and 67 4 0 9 kyr ago

the mid pleistocene climate transition onset of 100 ka cycle lags ice volume build up by 280 ka the mid pleistocene climate transition mpt is the complex climatic change which brought the late pleistocene ice ages we explore the mpt in the time and frequency domains by new methods of time series analysis high resolution oxygen isotope records reveal that the ice volume related increase in 18o mean amplitude 0 29 0 05 1 transition midpoint 922 12 ka duration 40 9 ka significantly preceded the abrupt increase in the amplitude of the 100 ka cycle at 641 9 ka this finding can be quantitatively simulated using a simple ice bedrock model in which due to the additional ice the calving threshold is exceeded the simulated calving events prior to 650 ka are separated by 77 ka whereas after 650 ka they occur pseudo periodically with a mean period of nearly 100 ka the cause for the delay of the 100 ka calving cycle was not a slow bedrock relaxation rather the coincidental combination of insolation existing ice mass and bedrock depression