a lower palaeolithic industry from the cromerian mis 13 baginton formation of waverley wood and wood farm pits bubbenhall warwickshire uk artefacts of cromerian mis 13 age recovered from extensions to the classic site of waverley wood farm pit warwickshire give new insights into the lower palaeolithic and pleistocene geological record of the english midlands the baginton formation in the area to the south and southwest of coventry has been the major source of lower palaeolithic artefacts in the midlands since the first discoveries in the 1930s current sand and gravel workings at waverley wood and wood farm pits near the village of bubbenhall have provided artefacts of quartzite andesite and flint together with sparse large mammal material some of the lower palaeolithic finds were in situ in the succession providing for the first time firm evidence of their geological provenance the variety and number of the artefacts allows detailed evaluation of the largest group of lower palaeolithic tools to be found in the west midlands the petrology of some of the tools and associated clasts in the gravels at the base of the baginton formation allow speculation on the origin of the rock types from northwest and eastern england which may have been brought to the west midlands by a pre anglian glaciation or just possibly by human transport copyright 2006 john wiley sons ltd

the west runton freshwater bed and the west runton mammoth summary and conclusions 1 introductionthis paper aims to synthesize the main conclusions from thevariouscontributionstothisissuecoveringthepalaeoenvironment palaeoclimate and age of the west runton freshwater bed wrfb as well as the life and death of the west runton mammoth wrm itself selectedpreviousresearchisalsobrie ydiscussed thewealthand breadth of the available information for the wrfb is almostunprecedented for any pleistocene site although there are somerelativelyminordifferencesininterpretation forthemostpartthereis verygood agreement between the various lines of evidence for completeness several mammalian taxa not otherwiseconsidered in this volume are included in table 1 which lists thecomplete vertebrate fauna so far recorded from the wrfb 2 sediments and depositional environmentasdiscussedbygibbardetal 2010 fieldandpeglar 2010 andmaul and par tt 2010 west 1980 described a composite vege tational sequence pieced together from pollen and plant macro fossil assemblages at several localities along the wrfb exposure he distinguished a beestonian late glacial cold assemblage l be atthe base of the sequence succeeded by a series of cromeriantemperate interglacial assemblages pollen subzones cr ia cr ib criia and cr iib of the cromerian interglacial although the entiresequence is not present at any one place and the depositsundoubtedly include hiatuses and some reworking see gibbardet al 2010 the various phases of vegetational development ofthe rst part of the cromerian are represented however siltshigherinthecliffwestofwestruntongap whichwestassignedtothe second half of the cromerian interglacial almost certainlybelong to a distinct younger episode zagwijn 1996 preece andpar tt 2000 gibbard et al 2010 consider that the wrfb sediments weredeposited in a uvial valley oor accumulation at least 100 mwide which trended west to east sub parallel to the modern cliffline the internal sequence of the wrfb is highly complex andshows considerable lateral and vertical discontinuity of individualunits representing widely varying rates of deposition and hiatusesduetonon depositionand orsubsequenterosion the depositionalbasin was subject to episodes of ooding on the one hand andperiodic drying out on the other nevertheless gibbard et al consider that as a whole the wrfb represents the late part of thebeestonian and the rst half of the cromerian interglacial which isconsistent with the pollen sequence described bywest 1980 thisinterpretation implies that the composite wrfb sequence spansseveral thousand years although there was never continuity ofdeposition at any one location according to gibbard et al deposition of thewrfb began duringthelate glacial partof thebeestonian cold stage in lling an unevengravel surface that was inherited from a pre existing braided cold climate stream and continued into the rst half of a temperate climate interglacial event the cromerian stage s s initial activestreamchannelswerefollowedbylowerenergyconditionsinwhich ne grained silt was deposited in standing water punctuated byshort intermittent ood events which washed in sand while localerosion of channel banks and oors also occurred subsequentdecreased ood intensity resulted in vertical accretion of ne grained organic fossiliferous sediments in carbonate rich springwater followed by increased organic deposition that producedatransitiontoblackdetritalsediment run offandriver owvelocitydiminished later as forest vegetation stabilised catchment andvalley oor ground surfaces the lower part of the wrfb wasdisturbed syndepositionally by water release structures and bio turbation by large mammals the mollusc fauna preece 2010 alsoindicates faster owing conditions at the base of the sequence

a single southern exit of modern humans from africa before or after toba abstract during the late pleistocene anatomically modern humans amh dispersed out of africa they first spread north with game across the sahara to the levant during the eemian interglacial c 125 ka and there is some recent evidence they may also have spread via arabia to the far east at the same time however they failed to continue to europe then occupied by neanderthals the sahara and arabia then reverted to aridity and amh vanished from the fossil record after 92 ka being later replaced in the levant again by neanderthals there is recent fragmentary evidence amh may also have spread via arabia to the far east but the archaeological record fades similarly long before the toba eruption there is no evidence of surviving non african dna lineages dating from anywhere near the eemian to contradict this narrative genetic evidence indicates that amh successfully left africa much later as a single group by the southern route to india since all non african uniparental lineages date to this later exit this appears to have been the only ultimately successful amh exit amh reached the isolated sahul continent at least by 48 ka and possibly by 60 50 ka amh only finally arrived in europe from south asia before 46 ka probably linked to climatic amelioration during mis 3 dating the definitive exit without adequate fossil evidence relies on disputed genetic dates with wide confidence intervals at the top end independent genetic dates combined with ash associated data from malaysia and from india argue for a pre toba exit although the consensus view is still largely post toba recent correction for non linearity due to purifying selection and recalibration of the mtdna clock has improved confidence in genetic dating but reduced the age of the main exit lineage l3 which effectively embodies its maximum estimate to just below that of toba 71 6 ka although relevant 95 confidence intervals ci 57 1 86 6 ka still include the toba event this weakening of the genetic argument puts more pressure on the archaeological evidence associated with toba ash and the need for diagnostic well dated fossil data between 90 70 ka

early middle pleistocene sediments at sidestrand northeast norfolk yield the most extensive preglacial cold stage beetle assemblage from britain fluvial sediments cromer forest bed formation at sidestrand northeast norfolk have yielded the most extensive preglacial early middle pleistocene cold arctic stage beetle assemblage known from britain the assemblage is composed of 59 taxa indicating severely cold and continental climatic conditions mutual climatic range reconstructions suggest that the mean temperature of the warmest month july was between 10 c and 13 c and the mean temperature of the coldest months january and february between 17 c and 10 c although the actual palaeotemperatures were probably towards the lower end of these ranges associated pollen and macroflora remains were poorly represented but all are known from other cold stage contexts excavations reveal that this freshwater arctic assemblage occurs within units between two important stratigraphic marker horizons the sidestrand hall member of the cromer forest bed formation and the first lowland glacigenic deposit happisburgh till member in eastern england although the ages of both remain equivocal recent amino acid chronologies of molluscan faunas from the sidestrand hall member indicate a mis 13 age with by inference a mis 12 age for the overlying arctic units with cold beetle fauna and for the happisburgh till member however the arctic units are separated from the two stratigraphic marker horizons by shallow marine deposits wroxham crag formation demonstrating at least two intervening phases of marine transgression and a cold climate marine regression the climatic significance of these marine transgressions and their chronostratigraphic implications are currently uncertain

an optimized scheme of lettered marine isotope substages for the last 1 0 million years and the climatostratigraphic nature of isotope stages and substages a complete and optimized scheme of lettered marine isotope substages spanning the last 1 0 million years is proposed lettered substages for marine isotope stage mis 5 were explicitly defined by shackleton 1969 but analogous substages before or after mis 5 have not been coherently defined short term discrete events in the isotopic record were defined in the 1980s and given decimal style numbers rather than letters but unlike substages they were neither intended nor suited to identify contiguous intervals of time substages for time outside mis 5 have been lettered or in some cases numbered piecemeal and with conflicting designations we therefore propose a system of lettered substages that is complete without missing substages and optimized to match previous published usage to the maximum extent possible our goal is to provide order and unity to a taxonomy and nomenclature that has developed ad hoc and somewhat chaotically over the decades our system is defined relative to the lr04 stack of marine benthic oxygen isotope records and thus it is grounded in a continuous record responsive largely to changes in ice volume that are inherently global this system is intended specifically for marine oxygen isotope stages but it has relevance also for oxygen isotope stages recognized in time series of non marine oxygen isotope data and more generally for climatic stages which are recognized in time series of non isotopic as well as isotopic data the terms stage and substage in this context are best considered to represent climatostratigraphic units and thus climatic stages and climatic substages because they are recognized from geochemical and sedimentary responses to climate change that may not have been synchronous at global scale

comment on environmental impact of the 73ka toba super eruption in south asia by m a j williams s h ambrose s van der kaars c ruehlemann u chattopadhyaya j pal and p r chauhan palaeogeography palaeoclimatology palaeoecology 284 2009 295 314 abstract williams et al williams m ambrose s h van der kaars s ruehlemann c chattopadhyaya u pal j n chauhan p 2009 environmental impact of the 73 ka toba super eruption in south asia palaeogeography palaeoclimatology palaeoecology 284 295 314 recently reported late pleistocene palaeoenvironment indicators from terrestrial sites in central india and a marine core from the bay of bengal they correlate isotopic data from soil carbonates and pollen from the marine core using occurrences of the youngest toba tuff ytt a widespread tephra erupted from the sumatran toba caldera 74 000 years ago they conclude that the toba eruption caused both climatic cooling and prolonged deforestation in south asia however consideration of the bases for these claims reveals that the ytt eruption is used as a chronological marker of cooling at the end of dansgaard oeschger interstadial 20 and no evidence is provided that the eruption caused or prolonged this process furthermore while the presented data add to the south asian palaeoenvironmental literature the applicability of the results to questions of impact on human and other populations is overstated

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

mis 13 12 in britain and the north atlantic understanding the palaeoclimatic context of the earliest acheulean research over the last two decades has revealed a rich record of lower palaeolithic occupation in britain before 450 000 years acheulean industries mode ii first appear in the later part of the early middle pleistocene marine isotope stage mis 19 13 this paper reviews i the age of the earliest acheulean in britain ii the climates under which the earliest acheulean industries occur as recorded by the palaeoecological assemblages that are found at key archaeological sites and iii the spatial and temporal pattern of regional climate change i e the magnitude of glacial interglacial cycles that occurred as a backdrop to the first arrival of mode ii archaeology in britain this review suggests that in britain the earliest acheulean populations arrived during mis 13 and that early occupation occurred under a range of climatic environmental settings but frequently under post temperate late interglacial or interstadial type cool boreal environments furthermore this review shows that the pattern of climate forcing in western europe during mis 13 12 was not analogous to the interglacial cycles of the past 450 000 years as latitudinal climate gradients appear to have been less pronounced the paper concludes by discussing the significance of these observations for understanding the arrival of the earliest acheulean in britain

geochemical and sedimentological control of the magnetic properties of hemipelagic sediments owing to their high sedimentation rates and wide areal extent hemipelagic sediments along continental borderlands are potentially important high resolution recorders of geomagnetic secular variation to assess this possibility we studied suboxic hemipelagic muds from the oregon continental slope and anoxic laminated diatomaceous oozes from the gulf of california these sediments were rapidly deposited with average sedimentation rates of 121 and 135 cm kyr respectively bulk sediment sedimentological and geochemical analyses indicate that the two areas represent contrasting depositional regimes the remanence in both environments resides in fine grained magnetite particles although minor amounts of hematite were observed in the topmost gulf of california sediments despite first order differences the sediments from both areas show similar downcore patterns of systematic increases in solid sulfur mainly as pyrite dramatic decreases in natural nrm anhysteretic and isothermal remanent magnetization intensities and accompanying shifts in the magnetic stabilities these changes are consistent with reduction and dissolution of the ferrimagnetic iron oxides with depth due to early diagenesis of organic matter the magnetic grain size distribution first appears to rapidly coarsen downcore as the smallest and most abundant grains are removed then slowly grows finer as the remaining particles dissolve no evidence was observed for authigenic formation of magnetite provided sufficient concentration and stability of the detrital magnetic particles paleomagnetic directions can survive this dissolution diagenesis however relative paleointensity determinations based on normalization of nrm by concentration in related parameters will give erroneous estimates of paleofield behavior in such diagenetically altered sediments

a synthesis of magnetostratigraphic results from pliocene pleistocene sediments cored using the hydraulic piston corer we present a summary evaluation of the distribution and qualitative ranking of the plio pleistocene magnetostratigraphic results obtained to date from deep sea drilling project and ocean drilling program piston cored sites a review of the published magnetostratigraphic records provides insights into the important extrinsic and intrinsic factors which affect the quality of the paleomagnetic records the extrinsic factors originate with drilling processes such as core barrel remagnetization and steps can be taken to reduce these effects and improve the data quality the distribution of the high quality records correlates well both with areas of terrigenous sediment input as well as regions of moderate biological productivity this suggests that important intrinsic factors include the origin of the original magnetic carrier in the sediment lithogenic or biogenic and the degree to which the magnetic carder has been affected by reduction diagenesis

fossil bacterial magnetite in deep sea sediments from the south atlantic ocean the magnetostratigraphy of deep sea sediment cores has proven to be a powerful and high resolution method of dating and comparing sedimentary records in contrast to this widespread application relatively few attempts have been made to analyse and identify the mineralogy grain size and origin of the carrier of the remanent magnetization1 2 it is widely assumed that dominant ferrimagnetic minerals in deep sea sediments are of lithogenic origin that is that they derive from oceanic or continental detritus volcanic ashfalls micrometeorites hydrothermal precipitation or chemical mineralization processes a very different view was taken by kirschvink and lowenstam3 who suggested that fossil remnants of magnetite mineralizing organisms in particular magnetotactic bacteria might play an important part in the magnetization of sediments deposited in certain detritus poor aquatic systems we have used rock magnetic diagnostic methods to characterize the magnetic phases in deep sea sediments from the south atlantic these phases were then extracted and studied with the electron microscope our results indicate that fossil bacterial magnetite is the main carrier of the natural remanent magnetization in sediments ranging in age from quarternary to eocene different types of bacterial magnetosomes were detected most of them occurring in chains of identical particles and nearly all of them falling into the theoretically determined4 size range of single domain magnetitite

biostratigraphic and aminostratigraphic constraints on the age of the middle pleistocene glacial succession in north norfolk uk considerable debate surrounds the age of the middle pleistocene glacial succession in east anglia following some recent stratigraphical reinterpretations resolution of the stratigraphy here is important since it not only concerns the glacial history of the region but also has a bearing on our understanding of the earliest human occupation of north western europe the orthodox consensus that all the tills were emplaced during the anglian marine isotope stage mis 12 has recently been challenged by a view assigning each major till to a different glacial stage before during and after mis 12 between trimingham and sidestrand on the north norfolk coast datable organic sediments occur immediately below and above the glacial succession the oldest glacial deposit happisburgh till directly overlies the sidestrand unio bed here defined as the sidestrand hall member of the cromer forest bed formation dating of these sediments therefore has a bearing on the maximum age of the glacial sequence this paper reviews the palaeobotany and describes the faunal assemblages recovered from the sidestrand unio bed which accumulated in a fluvial environment in a fully temperate climate with regional deciduous woodland there are indications from the ostracods for weakly brackish conditions significant differences are apparent between the sidestrand assemblages and those from west runton the type site of the cromerian stage these differences do not result from contrasting facies or taphonomy but reflect warmer palaeotemperatures at sidestrand and a much younger age this conclusion is suggested by the higher proportion of thermophiles at sidestrand and the occurrence of a water vole with unrooted molars arvicola rather than its ancestor mimomyssavini with rooted molars amino acid racemisation data also indicate that sidestrand is significantly younger than west runton these data further highlight the stratigraphical complexity of the cromerian complex and support the conventional view that the happisburgh till was emplaced during the anglian rather than the recently advanced view that it dates from mis 16 moreover new evidence from the trimingham lake bed sidestrand cliff formation above the youngest glacial outwash sediments briton s lane formation indicates that they also accumulated during a middle pleistocene interglacial probably mis 11 all of this evidence is consistent with a short chronology placing the glacial deposits within mis 12 rather than invoking multiple episodes of glaciation envisaged in the new glacial stratigraphy during mis 16 12 10 and 6 copyright 2009 john wiley sons ltd

all toba tephra occurrences across peninsular india belong to the 75 000 yr b p eruption abstract a controversy currently exists regarding the number of toba eruptive events represented in the tephra occurrences across peninsular india some claim the presence of a single bed the 75 000 yr old toba tephra others argue that dating and archaeological evidence suggest the presence of earlier toba tephra resolution of this issue was sought through detailed geochemical analyses of a comprehensive suite of samples allowing comparison of the indian samples to those from the toba caldera in northern sumatra malaysia and importantly the sedimentary core at odp site 758 in the indian ocean a core that contains several of the earlier toba tephra beds in addition two samples of toba tephra from western india were dated by the fission track method the results unequivocally demonstrate that all the presently known toba tephra occurrences in peninsular india belong to the 75 000 yr b p toba eruption hence this tephra bed can be used as an effective tool in the correlation and dating of late quaternary sedimentary sequences across india and it can no longer be used in support of a middle pleistocene age for associated acheulian artifacts

the toba volcanic super eruption environmental change and hominin occupation history in india over the last 140 000 years a prolonged interdisciplinary fieldwork program was initiated in india to investigate the impact of the toba super eruption on terrestrial ecosystems and hominins fieldwork was centered on the jurreru river valley and the middle son river valley in southern and northern india archaeological sites span from 140 000 years ago through to the holocene providing a long term view about hominin occupation history primary air fall deposits of the young toba tuff ytt were identified and changes in terrestrial environments prior to and after the super eruption are indicated prior to the toba eruption drying of local ecological settings was underway the emplacement of ash on landscapes and its subsequent erosion had local ecological and hydrological effects although drier conditions are indicated after the deposition of the ash deposits a mosaic of environments was present in india indicating that animals and hominins could have survived the volcanic event evidence indicates that middle paleolithic industries in stratified contexts are present in india prior to and after the toba super eruption middle paleolithic hominins appear to have survived the negative effects of the volcanic eruption and climatic fluctuations in the late pleistocene middle paleolithic industries produced from ca 77e38 000 years ago in india were probably manufactured by homo sapiens

aerosol size confines climate response to volcanic super eruptions extremely large volcanic eruptions have been linked to global climate change biotic turnover and for the younger toba tuff ytt eruption 74 000 years ago near extinction of modern humans one of the largest uncertainties of the climate effects involves evolution and growth of aerosol particles a huge atmospheric concentration of sulfate causes higher collision rates larger particle sizes and rapid fall out which in turn greatly affects radiative feedbacks we address this key process by incorporating the effects of aerosol microphysical processes into an earth system model the temperature response is shorter 9 10 years and three times weaker 3 5 k at maximum globally than estimated before although cooling could still have reached 12 k in some midlatitude continental regions after one year the smaller response plus its geographic patchiness suggests that most biota may have escaped threshold extinction pressures from the eruption

improved age constraint for pre and post anglian temperate stage deposits in north norfolk uk from analysis of serine decomposition in bithynia opercula the new glacial stratigraphy ngs of britain postulates that deposits hitherto assigned to the anglian glaciation in marine isotope stage mis 12 represent mis 16 12 10 and 6 this controversial idea can be tested at sidestrand in north norfolk where fossiliferous temperate stage deposits underlie the oldest and overlie the youngest of the glacial deposits previous work has considered biostratigraphy and amino acid dating of these temperate stage deposits but did not achieve tight age constraint using the amino acid evidence alone the total hydrolysable amino acid fraction in intra crystalline protein from bithynia tentaculata opercula has previously been analysed for concentrations of serine and alanine statistical screening of these data gives alanine serine ratios of 4 572 0 114 for the sidestrand hall member beneath the glacial deposits and 3 564 0 091 for the sidestrand cliff formation overlying the glacial deposits these ratios imply ages of mis 13a and 11c respectively indicating the latest cromerian and early hoxnian interglacials and invalidating the ngs copyright 2009 john wiley sons ltd

ultra distal tephra deposits from super eruptions examples from toba indonesia and taupo volcanic zone new zealand abstract voluminous rhyolitic eruptions from toba indonesia and taupo volcanic zone tvz new zealand have dispersed volcanic ash over vast areas in the late quaternary the 74 ka youngest toba tuff ytt eruption deposited ash over the bay of bengal and the indian subcontinent to the west the 340 ka whakamaru eruption tvz deposited the widespread rangitawa tephra dominantly to the southeast in addition to occurrences northwest of vent extending across the landmass of new zealand and the south pacific ocean and tasman sea with distal terrestrial exposures on the chatham islands these super eruptions involved 2500 km 3 and 1500 km 3 of magma dense rock equivalent dre respectively ultra distal terrestrial exposures of ytt at two localities in india middle son valley madhya pradesh and jurreru river valley andhra pradesh at distances of 2000 km from the source caldera show a basal primary ashfall unit 4 cm thick although deposits containing reworked ash are up to 3 m in total thickness exposures of rangitawa tephra on the chatham islands 900 km from the source caldera are 15 30 cm thick at more proximal localities 200 km from source rangitawa tephra is 55 70 cm thick and characterized by a crystal rich basal layer and normal grading both distal tephra deposits are characterized by very fine ash with high pm 10 fractions and are crystal poor glass chemistry stratigraphy and grain size data for these distal tephra deposits are presented with comparisons of their correlation dispersal and preservation using field observations ash transport and deposition were modeled for both eruptions using a semi analytical model hazmap with assumptions concerning average wind direction and strength during eruption column shape and vent size model outputs provide new insights into eruption dynamics and better estimates of eruption volumes associated with tephra fallout modeling based on observed ytt distal tephra thicknesses indicate a relatively low

river response to quaternary climatic fluctuations evidence from the son and belan valleys north central india abstract the last glacial period was cold and dry in peninsular india in north central india the interval from 39 9 to 16 3 ka was associated with widespread and prolonged aggradation in the son and belan valleys the aggradation ended with sustained vertical incision after 16 3 ka and reflects a return to warmer wetter conditions in this region it would appear that terminal pleistocene to holocene river incision was broadly synchronous with a strong summer monsoon regime and higher levels of river discharge and the preceding river aggradation with lower discharge and a weaker or more variable summer monsoon regime two older phases of prolonged aggradation followed by vertical incision are evident in the son and belan valleys before 39 ka one of these phases is centred towards 73 4 ka when ash from the toba mega eruption in sumatra was deposited across peninsular india the following phase of aggradation has yielded infrared stimulated luminescence ages of 58 6 and 45 12 ka the youngest phase of aggradation began towards 5 5 ka and seems to mark a return to a weaker summer monsoon regime

temporal trends of magnetic dissolution in the pelagic realm gauging paleoproductivity abstract magnetic hysteresis data from the western equatorial pacific suggest that the preservation of magnetic remanence in pelagic carbonates is controlled by paleoproductivity hysteresis excursions 100 k y intervals are linked here to greater magnetic dissolution associated with increased glacial organic carbon supply changes in the redox boundary coupled to glacial terminations result in anomalous magnetic features which are preserved in the sedimentary record these high frequency variations are superimposed on a longer term signal of magnetic dissolution which may reflect decreased productivity since the miocene

oceanic circulation as an element in palaeogeographical reconstructions the arenig early ordovician as an example a new conceptual palaeo oceanographical model is outlined in this paper the model differs from previous models by using shifts in hadley circulation caused by orbital variations and the rotation rate of the earth to locate the position of the planetary oceanic low and high pressure systems around which the planetary ocean surface currents flow adapting the model to the arenig early ordovician the temperate low pressure zones were found to be located at 50 latitude and the subtropical high pressure zones at 25 latitude traditionally most palaeozoic palaeogeographical recon structions are reconstructed using palaeomagnetic data supplemented with data from climate sensitive lithofacies and palaeo biogeographical distributions however as a new approach in palaeogeographical reconstructions the con ceptual palaeo oceanographical model is combined with palaeobiogeographical data for the arenig series comple menting the palaeomagnetic data and resulting in a new refined palaeogeographical reconstruction

the early and early middle pleistocene context of human occupation and lowland glaciation in britain and northern europe abstract this paper reviews the stratigraphical and environmental contexts of early human occupation and lowland glaciation in britain and northern europe it highlights the fragmentary nature of most of the critical sequences and the inadequacy of existing stratigraphical frameworks the earliest archaeology known from nw europe has been reported from happisburgh 3 a site on the norfolk coast the flint artefacts from here were recovered from sediments previously assigned to the pastonian stage of the early pleistocene however the mammalian assemblage from happisburgh 3 differs from other local sites attributed to the pastonian indicating a younger age within the early pleistocene the sediments have reversed palaeomagnetic polarity and have palynological features inviting correlation with the leerdam interglacial in the dutch bavelian complex the interglacials of the british cromerian complex are compared and their archaeological record reviewed at most of these sites the archaeology includes hand axes associated with a mammalian assemblage containing the water vole arvicola but at pakefield suffolk a core and flake industry is associated with the ancestral mimomys savini this together with the even older record from happisburgh 3 indicates earlier periods of human occupation than previously known from nw europe at least five temperate episodes with distinct faunal assemblages are now recognized in the british early middle pleistocene but these are unlikely to equate directly with odd numbered stages of the marine isotope record this biostratigraphical framework conflicts with a new glacial stratigraphy for east anglia which proposes glaciations during mis 16 12 10 and 6 evidence is reviewed from sidestrand and trimingham where datable organic sediments occur directly beneath and above the middle pleistocene glacial succession indicating that it was emplaced entirely during the anglian glacial stage mis 12 a new stratigraphical framework is provided ranking british sites in order of relative age which is then compared with a revised scheme for the dutch late early and early middle pleistocene succession the revisions involve the relocation of the waardenburg interglacial interglacial 1 to the bavelian complex and the use of the brunhes matuyama palaeomagnetic reversal to define both the base of the dutch cromerian complex and the early middle pleistocene boundary moreover following recent re interpretation the noordbergum interglacial interglacial iv and glacial c are removed from the cromerian complex and are correlated with mis 11 and mis 12 respectively this scheme imposes greater consistency between the british and dutch successions as well as conformity with guidelines recommended by the international stratigraphic commission

discontinuity in the record for hominin occupation in south western europe implications for occupation of the middle latitudes of europe abstract recent discoveries of evidence for hominin activity in britain before mis 13 challenge previous understanding of the nature of the earliest colonization of nw europe insights into the nature of colonization in this region may be obtained by examining the much richer fossil and archaeological record from iberia it has generally been assumed that southern europe was permanently occupied after the first appearance of hominins in the region and that it provided a reliable source for populations re colonizing areas further north however continuity of occupation in these southern areas is still to be demonstrated this paper provides an outline of the palaeoenvironmental archaeological and fossil evidence from iberia during the early pleistocene and early middle pleistocene this evidence is used to argue that hominin occupation in this region and time period was discontinuous this may help to address a number of questions about the earliest occupation history of nw europe who were the colonists and where did they come from were they strongly limited by climatic conditions were source populations always available in nearby areas and did this influence the permanency of occupation in this region

climate response to the toba super eruption regional changes climatic consequences of the young toba tuff ytt eruption about 73 ka are a crucial argument in the current discussion about the fate of modern humans especially in africa and asia earth system model esm simulations of the ytt eruption are used to investigate its regional climate impacts in particular focusing on areas relevant to human evolutionary issues during that time uncertainties concerning the stratospheric sulphur emission for the ytt eruption are addressed by comparing esm simulations of a 100 times pinatubo like eruption as an upper and a 3 times pinatubo like tambora eruption as a lower estimate information about transient changes in vegetation types after the ytt eruption are obtained by forcing an offline dynamical global vegetation model with the climate anomalies simulated by the esm under both glacial and interglacial background climate conditions the simulated temperature changes in those areas that were inhabited by humans suggest thermal discomfort but not a real challenge for survival precipitation is reduced in all regions during the first two years but recovers quickly thereafter some catchments in these regions ganges brahmaputra nile experience an over compensation in precipitation during the third to fifth post eruption years which is also reflected in anomalously strong river runoffs change in vegetation composition may have created the biggest pressure on humans who had to adapt to more open space with fewer trees and more grasses for some decades especially in the african regions the strongest environmental impacts of the ytt eruption are simulated under interglacial background conditions suggesting that the climate effects of the ytt eruption did not impact humans on a major scale and for a period long enough to have dramatic consequences for their survival

geochemical fingerprinting of the widespread toba tephra using biotite compositions toba caldera sumatra is one of the largest and most explosive volcanoes on earth erupting some of the most voluminous volcanic deposits chronologically these eruptions are 790 ka older toba tuff 500 ka middle toba tuff and 74 ka younger toba tuff ash from these eruptions is dispersed over the entire region from india through malaysia to indonesia where it forms isochronous markers that have been documented in a variety of sedimentary sequences including palaeoclimate archives and archaeological sites the chemistry of the volcanic glass shards usually enables distal volcanic ash units to be correlated to a known eruption however the magmas involved in the three largest toba eruptions are compositionally similar and consequently the glass chemistry that is used to differentiate eruption units cannot be used to identify distal deposits here we show that the composition of biotite crystals which occur with glass in the distal deposits can be used to fingerprint the deposits of the younger toba tuff biotite in younger toba tuff has a lower feo mgo 2 1 2 6 than in the products of older eruptions 2 8 3 7 correlations using these distinct biotite compositions indicate that the ash found in malaysia and in archaeological sites in india was from the 74 ka younger toba tuff eruption

late acheulean hominins at the marine isotope stage 6 5e transition in north central india single grain optically stimulated luminescence dating was applied to late quaternary sediments at two sites in the middle son valley madhya pradesh india designated bamburi 1 and patpara these sites contain late acheulean stone tool assemblages which we associate with non modern hominins age determinations of 140 120 ka place the formation of these sites at around the marine oxygen isotope stage 6 5 transition placing them among the youngest acheulean sites in the world we present here the geochronology and sedimentological setting of these sites and consider potential implications of late pleistocene archaic habitation in north central india for the initial dispersal of modern humans across south asia

reply to the comment on environmental impact of the 73 ka toba super eruption in south asia by m a j williams s h ambrose s van der kaars c ruehlemann u chattopadhyaya j pal p r chauhan palaeogeography palaeoclimatology palaeoecology 284 2009 295 314 abstract haslam and petraglia raise three broad questions concerning our paper environmental impact of the 73 ka toba super eruption in south asia by martin a j williams stanley h ambrose sander van der kaars carsten ruehlemann umesh chattopadhyaya jagannath pal parth r chauhan palaeogeography palaeoclimatology palaeoecology 284 2009 295 314 a what was the relationship between the 73 ka toba eruption and the cold stade between the dansgaard oeschger interstades 20 and 19 b what was the regional impact of the eruption on vegetation c what was the possible effect of the eruption upon humans and mammals in response to questions a and b we note that the 73 ka toba eruption was followed by several centuries of intense cooling and wind blown dust accession in the greenland gisp2 ice core by a change from forest to grassland or open woodland in central india carbon isotopic analysis and in the wider region pollen analysis of a marine sediment core in the bay of bengal in regard to c the genetic evidence is as yet too imprecisely dated to demonstrate causality as is the archaeological evidence cited by haslam and petraglia in favour of minimal impact future work supported by higher resolution chronologies than are presently available is needed to provide a less equivocal picture of the environmental impact of the 73 ka toba eruption

superparamagnetism and reduction diagenesis in pelagic sediments enhancement or depletion superparamagnetic grains ultra fine d 0 05 m particles unable to retain a remanence at room temperature have come under increased scrutiny as indicators of the diagenetic and authigenic history of sedimentary rocks in marine sediments fine grained magnetite with large surface area to volume is thought to be preferentially removed during magnetic mineral reduction on the basis of new magnetic hysteresis low temperature and geochemical studies of pelagic sediments from the western equatorial pacific ocean it is proposed that reduction processes increase rather than deplete the ultra fine magnetic grain population at the modern fe redox boundary enhanced superparamagnetism coincides with a coarsening of remanence carrying grains superparamagnetism also tracks proposed temporal changes in magnetite reduction caused by climatically driven fluctuations in organic carbon corg supply together with hysteresis characteristics changes in superparamagnetism may help the identification of paleointensity artifacts resulting from non steady state magnetic mineral reduction

magnetofossils the magnetization of sediments and the evolution of magnetite biomineralization magnetite fe 3o 4 is one of the most stable carriers of natural remanent magnetization nrm in sedimentary rocks and paleomagnetic studies of magnetite bearing sediments such as deep sea cores and pelagic limestones have provided a detailed calibration between the biostratigraphic and magnetic polarity time scales despite this important role there is as yet a very poor understanding of how ultrafine grained 0 1 m magnetite is formed transported and preserved in marine environments a major conceptual advance in our understanding of these processes is the recent discovery that biogenic magnetite formed by magnetotactic bacteria and or other magnetite precipitating organisms is responsible for much of the stable magnetic remanence in many marine sediments and sedimentary rocks since these magnetite particles are of biogenic origin they are termed properly magnetofossils kirschvink chang 1984

age limits on middle pleistocene glacial sediments from osl dating north norfolk uk the lowland region of north norfolk contains some of the best preserved evidence for glacial deposition during the middle pleistocene in northwest europe despite the importance of these deposits there is limited chronological control and it is debated whether they belong to a single glaciation equated to the anglian glaciation marine isotope stage 12 or represent deposition over a number of middle pleistocene cold stages in order to develop an improved chronology for glaciation in this region we obtained 18 samples for optical stimulated luminescence osl dating from glacial outwash facies samples of coarse grained quartz sand were measured using the sar single aliquot regenerative dose protocol the low radioactive isotope concentrations in sediments of this region enable the traditionally accepted age limit of luminescence dating to be extended the form of the dose response curves pre heat plateaux tests and dose recovery experiments also indicate that laboratory doses can be reliably measured in these samples age overestimation due to partial bleaching is thought to be insignificant the osl ages suggest that the glacial sediments studied were deposited during mis 12 rather than in different post mis 12 stages

the great arc of dispersal of modern humans africa to australia abstract during the late pleistocene anatomically modern humans amh dispersed out of africa across the continents their routes obeyed the limitations placed on any large terrestrial mammal dependent on daily drinking water following certain climate permissive corridors amh first spread north with game across the sahara to the levant during the eemian interglacial c 125 ka but failed to continue to europe then occupied by neanderthals the savannah ecosystem in north africa and the middle east then dried up and amh vanished from the levantine fossil record being replaced there by neanderthals later amh successfully left africa as a single group by the southern route to india the added ability to make short but deliberate open water crossings allowed them first to cross the mouth of the red sea from eritrea and subsequently wallace s line to reach the isolated sahul continent at least by 48 000 years ago and possibly by 60 50 000 years ago they only finally arrived in europe from south asia around 45 50 000 years ago probably linked to climatic amelioration during ois 3

an aminostratigraphy for the british quaternary based on bithynia opercula aminostratigraphies of quaternary non marine deposits in europe have been previously based on the racemization of a single amino acid in aragonitic shells from land and freshwater molluscs the value of analysing multiple amino acids from the opercula of the freshwater gastropod bithynia which are composed of calcite has been demonstrated the protocol used for the isolation of intra crystalline proteins from shells has been applied to these calcitic opercula which have been shown to more closely approximate a closed system for indigenous protein residues original amino acids are even preserved in bithyniid opercula from the eocene showing persistence of indigenous organics for over 30 million years geochronological data from opercula are superior to those from shells in two respects first in showing less natural variability and second in the far better preservation of the intra crystalline proteins possibly resulting from the greater stability of calcite these features allow greater temporal resolution and an extension of the dating range beyond the early middle pleistocene here we provide full details of the analyses for 480 samples from 100 horizons 75 sites ranging from late pliocene to modern these show that the dating technique is applicable to the entire quaternary data are provided from all the stratotypes from british stages to have yielded opercula which are shown to be clearly separable using this revised method further checks on the data are provided by reference to other type sites for different stages including some not formally defined additional tests are provided by sites with independent geochronology or which can be associated with a terrace stratigraphy or biostratigraphy this new aminostratigraphy for the non marine quaternary deposits of southern britain provides a framework for understanding the regional geological and archaeological record comparison with reference to sites yielding independent geochronology in combination with other lines of evidence allows tentative correlation with the marine oxygen isotope record

dissolution and pyritization of magnetite in anoxie marine sediments concentrations of magnetite were determined with depth in sediments of varying h2s content taken from long island sound foam nwc and sachem sites and from a site in the rapidly depositing subaqueous portion of the mississippi delta for the three long island sound sites dissolution of magnetite during burial is clearly demonstrated and for all four sites the rate of magnetite dissolution is proportional to the concentration of dissolved pore water sulfide by combining magnetite depth distributions with sedimentation rate data and measurements of dissolved sulfide we find that magnetite dissolution is well described by the following rate law dcmagdt 1 1 10 5c0 5bcmagamag where cmag is the concentration of magnetite grams per gram of sediment cs is the concentration of dissolved sulfide mm and amag is the specific surface area of magnetite in the sediment cm2 per gram of magnetite this equation means that for a typical range of magnetite surface areas and dissolved sulfide concentrations the half life of magnetite in anoxic marine sediments ranges from about 50 to 1000 years sem observations of magnetite grains from the different sediment sites reveal that magnetite dissolution may be accompanied by extensive replacement by pyrite this only occurs if magnetite is in contact with high concentrations of h2s 1 mm for relatively long periods of time several hundred years with low concentrations of h2s 1 mm magnetite dissolution occurs without identifiable pyrite replacement we suggest that this feature of magnetite diagenesis may prove to be a useful paleosulfide indicator

toba ash on the indian subcontinent and its implications for correlation of late pleistocene alluvium the toba ash occurs extensively in the indian subcontinent and marks a ca 74 000 yr old event in the bay of bengal and indian ocean it is about 10 cm thick whereas in several alluvial basins it is usually 1 3 m thick the latter occurs in a partly reworked state but as nearly chemically pure first cycle sediments the ash has a broad northwesterly dispersal pattern samples of ash from the indian subcontinent compare closely with the youngest 74 000 yr b p toba tuff and the deep sea toba ash in bulk chemical composition ree signature and bubble wall shard morphology however a more proximally located and thicker 2 5 m ash bed from the alluvial basins in the gneissic area and close to east coast has a lower magnitude negative eu anomaly possibly because of minor contamination by feldspathic silt quaternary sediments in the central narmada and middle son basins contain rich late and middle pleistocene mammalian and cultural records based on the presence of the ash layer marker and stratigraphic relations late pleistocene sediments within the subcontinent can be correlated with those from central india and the deep sea

alder creek sanidine acs 2 a quaternary 40ar 39ar dating standard tied to the cobb mountain geomagnetic event accurate 40ar 39ar dating of quaternary and holocene samples requires a standard neutron fluence monitor of appropriate age this standard should be isotopically homogenous at the scale of analysis and should be well intercalibrated with other standards several such standards have been proposed including sanidine from the 1 19 ma alder creek rhyolite acs turrin et al 1994 turrin b d donnely nolan j m hearn b c jr 1994 40ar 39ar ages from the rhyolite of alder creek california age of the cobb mountain normal polarity subchron revisited geology 22 251 254 this sanidine is satisfactorily homogeneous well intercalibrated with fish canyon sanidine fcs renne et al 1998 renne p r swisher c c deino a l karner d b owens t l depaolo d j 1998 intercalibration of standards absolute ages and uncertainties in 40ar 39ar dating chem geol 145 117 152 and is linked to the astronomically calibrated magnetic polarity time scale since the alder creek rhyolite lava is the type occurrence of the cobb mountain event cm we collected 408 kg of this rock from which we anticipate being able to extract more than 8 kg of 425 m sanidine crystals analyses of sanidine phenocryts from the acs 2 from three separate irradiations and two distinct grain sizes yield ages ranging from 1 190 0 004 to 1 194 0 003 ma1 with a weighted mean age of 1 193 0 001 ma mswd 0 74 n 225 based on fcs 28 02 ma renne et al 1998 renne p r swisher c c deino a l karner d b owens t l depaolo d j 1998 intercalibration of standards absolute ages and uncertainties in 40ar 39ar dating chem geol 145 117 152 the value of the intercalibration factor renne et al 1998 renne p r swisher c c deino a l karner d b owens t l depaolo d j 1998 intercalibration of standards absolute ages and uncertainties in 40ar 39ar dating chem geol 145 117 152 is rfcsacs 2 0 04229 0 00012 n 8 identical with that of the original acs measurements 0 04229 0 00012 renne et al 1998 renne p r swisher c c deino a l karner d b owens t l depaolo d j 1998 intercalibration of standards absolute ages and uncertainties in 40ar 39ar dating chem geol 145 117 152 the age of acs 2 is in agreement with the recent astronomical calibration of the cm event 1 215 to 1 190 ma channell j e t mazaud a sullivan p turner s raymo m e 2002 geomagnetic excursions and paleointensities in the matuyama chron at ocean drilling program sites 983 and 984 iceland basin j geophys res 107 6 10 1029 2001jb000491 the apparent absence of xenocrysts and excess argon suggests that multigrain analyses are feasible and therefore the amount of material can be tailored to experimental requirements aliquots from various grain sizes will be available upon request zircon is also potentially available which may be of interest to u th he researchers