submerged and eroded drumlins off northeastern massachusetts abstract streamlined oval shaped oriented topographic highs in massachusetts bay are identified as the erosional remnants of drumlins the topographic highs correlate with outlines of lag gravel deposits on the sea floor and both the highs and lag gravel seafloor footprint have a distinct east southeast long axis trend this trend is similar to the preferred orientation of the long axes of drumlins in the boston basin and indicates the flow direction of the late wisconsinan laurentide ice sheet modification of the drumlins occurred during two passages of the shoreline the first during the late wisconsinan regression when the drumlins were only slightly eroded the second passage of the shoreline occurred during the marine transgression when erosion in the form of cliff face retreat removed the upper part of the drumlins

co2 isotopes as tracers of firn air diffusion and age in an arctic ice cap with summer melting devon island canada 1 firn air and ice have been sampled and analyzed for trace gases co2 n2o ch4 and co and isotopes 14c 13c and 18o of co2 3h of ice at 3 m intervals from the surface to the depth of closure at 60 m on the devon island ice cap a low elevation permanent glacier in the canadian arctic islands to investigate firn diffusion and the effects of summer melting the 14co2 profile from the permeable firn includes the 1963 thermonuclear peak at a depth of 53 9 1 5 m the twofold increase and rapid decay that characterize the recent atmospheric history for 14co2 provide a robust atmospheric scenario that is used with a firn air diffusion model to inversely construct the firn diffusivity profile the results show a permeable but essentially nondiffusive zone from 50 to 60 m depth a firn ice age profile was produced from density measurements and accumulation rates were calibrated with the depth of the 1963 thermonuclear 3h peak the average ages for co2 in the sampled firn air profile were determined by a new method based on the rate of 18o exchange between co2 and the ice matrix calibrated with the 1963 peak for thermonuclear 14co2 a 21 2 year reaction halftime is calculated for exchange taking place at the firn temperature of 22 8 c on devon this gives an average age of 54 9 6 0 12 0 years for firn air at 60 m depth in 140 year old ice thus co2 has a mean age 85 years younger than associated ice at the point of occlusion the measured in firn air provides no indication of alteration by summer melting which is attributed to a high degree of convective and diffusive flushing of the upper firn as shown by diffusion modeling this suggests that ice sheets with summer melt layers can reliably preserve atmospheric trace gas signals

successful application of uranium series dating of fossil bone abstract a novel approach to uranium series disequilibrium dating is presented and used successfully to date bones from several european archaeological and palaeontological sites a method is described based on a proposed mechanism of uranium uptake and fixation derived from present understanding of the biochemistry of fossilizing bones and the geochemistry of uranium stability of uranium in fossil bone is predicted under particular conditions of local depositional environment and the importance of the inhomogeneous distribution of uranium through bone to uranium series dating is explained sample bones from several different sites have been examined taking into account the three factors of uptake mechanism uranium distribution and sedimentary environment and have yielded ages in good agreement with those derived by alternative dating methods or from chronologically fixed stratigraphical positions

relative sea level changes from ne ireland during the last glacial termination deglacial sea level records from ne ireland between 21 and 11 cal ka bp record marine transgressions and sensitive lithospheric responses to ice loading the sawtooth sea level curve contains four intervals characterized by 1 strong net uplift subaerial channelling and a global meltwater pulse 21 19 cal ka bp 2 ice loading isostatic depression and high relative sea level 19 17 5 cal ka bp 3 ice loading renewed isostatic depression and high relative sea level for 1000 years 17 14 5 cal ka bp 4 catastrophic ice wastage rapid uplift and lowstand 14 5 13 cal ka bp geophysical models do not capture these fluctuations

dated evidence of the interaction between humans and megafauna in the late pleistocene of sergipe state northeastern brazil abstract we present a radiocarbon date 12 742 12 562 cal bp for an eremotherium laurillardi tooth found in sergipe state northeastern brazil which shows anthropogenic marks our result provides additional information and reinforces the hypothesis that humans was present in south america earlier than accepted currently and interacted with megafauna during the late pleistocene in this region

unveiling the taphonomy of elusive natural tank deposits a study case in the pleistocene of northeastern brazil abstract fossiliferous natural tanks are a singular type of sedimentary deposit restricted to northeastern brazil which usually preserves a diversified late pleistocene vertebrate fauna their fossil assemblages are taxonomically well known but their taphonomy is poorly understood this work presents a detailed taphonomic analysis of a tank deposit from jirau site ceara state northeastern brazil to improve understanding of the processes that influenced fossil deposition and preservation in natural tanks and to shed light on paleoecological and paleoenvironmental aspects related to the late pleistocene vertebrate fauna from northeastern brazil tank deposits from different localities were also compared to figure out potential taphonomic patterns among them additionally comparisons with other brazilian pleistocene deposits and other debris flow deposits bearing vertebrates were undertaken the study revealed the predominance of the megamammal eremotherium laurillardi in the deposit which we attributed to its abundance in late pleistocene biocoenosis as well as bone resistance scarcity of non mammalian vertebrates is likely related to their paucity in late pleistocene biocoenosis time averaging was evidenced by the co occurrence of different weathering petrographic and color patterns and may have affected the ontogenetic profile of the accumulation relative to the original biocoenosis analyses of weathering stages tooth and trample marks indicate wide exposition of the thanatocoenosis before burial abrasion and petrographic patterns allow reworking in the assemblage to be inferred permineralization and substitution are the fossilization processes observed taphonomy indicates that floods deposited clasts and bioclasts in the tank under an arid or semiarid climate in a debris flow regime comparison with other tank deposits revealed several similar taphonomic features and differences related to sedimentology and stratigraphy taphonomic similarities suggest rather homogeneous environmental conditions in the northeastern brazil during the late pleistocene as previously suggested by taxonomic studies comparison with other brazilian pleistocene deposits shows that tanks have more temporal fidelity than caves coastal and some fluvial deposits the jirau vertebrate accumulation was produced by the reworking and transport of skeletal elements accumulated in a nearby thanatocoenosis and is similar to other better known debris flow hosted vertebrate accumulations

the quaternary vertebrate fauna of the limestone cave gruta do ioio northeastern brazil o quaternary pleistocene bahia brazil cave deposits abstract the present study reports the quaternary vertebrate fauna of gruta do ioi a partially submerged limestone cave located in central bahia northeastern brazil a semi arid weather prevails nowadays in the area which is mostly covered by a xeric low arboreal scrubland known as caatinga the identified taxa include rhamdia osteichtyes siluriformes caiman crocodyliformes caimaninae myocastor cf myocastor coypus rodentia myocastoridae holochilus sciureus rodentia sigmodontinae natalus cf natalus macrourus chiroptera natalidae tonatia bidens trachops cirrhosus chiroptera phyllostomi dae and eira cf eira barbara carnivora mustelidae whereas rhamdia and caiman have scarce fossil records the recovered mammals have already been reported from quaternary localities of northeastern brazil although only two of them are present in the current local fauna taphonomic signatures and the nature of the fossiliferous site indicate that the vertebrates lived inside or nearby the cave including the swamp by its main entrance radiocarbon dating of dental bioapatite yielded calibrated ages between 19 980 and 22 040 bp this indicates that the accumulation started at least during the late pleistocene within the last glacial maximum in agreement with the mode of life of most taxa recognized here previous studies indicated that this was a wetter period in the region

taphonomic analysis of a late pleistocene vertebrate accumulation from lage grande paleontological site pernambuco state northeastern brazil new remarks on preservational aspects of tank deposits biological stratigraphic and temporal processes act on the origin of fossil concentrations the influence of these phenomena on fossil vertebrate accumulations from tank deposits recently began to be analyzed in detail this paper documents taphonomic patterns recognized in the late pleistocene fossil vertebrate accumulation from a tank deposit of lage grande paleontological site lgps pernambuco state northeastern brazil the preservation observed in lgps differs strongly from the expected for tank accumulations and given the high quality of preservation and the low rate of time averaging inferred indicated by the low degrees of surface bone modifications it seems reasonable that lgps accumulation reflects nearly non biased biocenotic patterns under this hypothesis eremotherium laurillardi was the most abundant species in the region of lage grande during the late pleistocene similarly to other areas with tank deposits surprisingly cingulates were rare or absent non mammalian vertebrates and glossotherium were rare in that area taphonomic signatures indicate that the thanatocoenosis of lage grande experienced a short time span of subaerial exposure prior to burial and short transport to inside the tanks by debris flows thus lgps accumulation can be classified as parautochthonous besides the inferred rapid burial of the lgps assemblage when compared to other tank accumulations another feature that may had generated the peculiar taphonomic setting of lgps accumulation is the uncommon pond like morphology of this deposit morphology of the tanks may be one additional factor responsible for differential preservation of vertebrates in this kind of deposit

fossil bats from the quaternary of serra da capivara northeast brazil abstract the serra da capivara national park in the southeast of state of piaui is widely recognized for its important archeological sites however in the areas surrounding the park there are also paleontological sites especially limestone caves where fossils of small mammals have been found this material was recovered from deposits attributed to the late pleistocene and early holocene previous works have listed the occurrence of eight species of bats in two caves toca do gordo do garrincho and toca da janela da barra do antoniao the present study reports new data on the chiroptera from serra da capivara based on cranio mandibular fragments from three caves from toca do barrigudo we identified tonatia sp phyllostomus discolor and artibeus planirostris the latter two species have also been identified from toca do serrote do artur in addition to lophostoma sp and eptesicus fuscus from toca do gordo do garrincho the record of desmodus rotundus is confirmed along with the identification of lophostoma sp thus the following taxa are recorded for the first time for the quaternary of the serra da capivara region lophostoma sp phyllostomus discolor and eptesicus fuscus all taxa currently occur in the area except eptesicus fuscus which has previously been recorded for the quaternary of brazil in the states of rio grande do sul and bahia suggesting a much wider geographical distribution at least until the beginning of the holocene which is corroborated by the serra da capivara findings

holocene survival of late pleistocene megafauna in china a critical review of the evidence late quaternary megafaunal extinction chronologies are poorly understood across eastern and southeast asia previous radiometric studies suggested that surprisingly many extinct late pleistocene large mammal species survived into the holocene in northern china bos primigenius coelodonta antiquitatis mammuthus primigenius and southern china ailuropoda baconi crocuta crocuta ultima megatapirus augustus stegodon orientalis sus cf xiaozhu indicating that chinese megafaunal extinctions may have been staggered across the late quaternary we critically re examined all radiometric evidence suggesting holocene survival of chinese late quaternary megafauna and conducted new dating of mammal material from reportedly holocene sites containing characteristically late pleistocene faunas evidence for holocene survival of any chinese late pleistocene megafaunal species is weak or untenable no previous radiometric dates used to support holocene megafaunal survival represent direct bone dates for species of interest and stratigraphic association between material yielding holocene dates and megafaunal remains is dubious at most sites concerns over accurate identification of faunal material further confuse claims for holocene survival of many species robust radiometric last occurrence dates for extinct chinese megafauna are all restricted to the late pleistocene similar to the timing of many other late quaternary megafaunal species extinctions elsewhere in eurasia and the americas c 2013 elsevier ltd all rights reserved

u series dating of bone using the diffusion adsorption model abstract u series dating of bone has suffered problems of reliability since its inception because bone remains an open system with respect to uranium commonly applied a priori assumptions of u uptake such as early uptake or linear uptake are inadequate because they have no physical or chemical bases no means of demonstrating which model is suitable for a particular bone and no intrinsic tests of reliability despite this and numerous examples of anomalous u series dates such assumptions are still routinely applied we address this problem using the diffusion adsorption d a model of u uptake millard and hedges 1996 which incorporates a physicochemical description of u uptake using this model we show how the u uptake of a bone responds to geochemical changes in the burial environment which can lead to phenomena such as the removal of u from bones leaching or u uptake late in their burial history recent uptake and we show how the overall uptake history is reflected in distributions profiles of u and u series isotopes across a bone section we present measurements of u concentration profiles and 230 th 234 u profiles on archeological bone from a number of different sites and burial environments and compare the results to profiles predicted by the d a model bones that have undergone complex uptake histories which include u leaching or recent uptake are identified on the basis of these profiles and rejected as unsuitable for dating for bones that appear to have undergone uptake under constant geochemical conditions the d a model is applied to calculate u series dates with much improved reliability

an improved glacial isostatic adjustment model for the british isles the glacial isostatic adjustment gia of the british isles is of interest due to the constraints that can be provided on key model parameters such as the global meltwater signal local ice sheet history and viscoelastic earth structure a number of recent studies have modelled relative sea level rsl data from this region to constrain model parameters as indicated in these studies the sensitivity of these data to both local and global parameters results in a highly non unique problem this study aims to address this inherent non uniqueness by combining a previously published british irish ice model that is based on the most recent geomorphological data with a new global ice sheet model that provides an accurate prediction of eustatic sea level change in addition constraints from global positioning system gps measurements of present day vertical land motion are considered alongside the entirety of rsl data from both great britain and ireland a model solution is found that provides a high quality fit to both the rsl data and the gps data within the range of earth viscosity values considered the optimal data model fits were achieved with a relatively thin lithosphere 71 km upper mantle viscosities in the range 4 6 1020 pa s and lower mantle viscosities 3 1022 pa s copyright 2011 john wiley sons ltd

cyclic sedimentation in brazilian caves mechanisms and palaeoenvironmental significance abstract caves associated with doline slopes in the tectonically stable area of eastern brazil display remarkable sequences of clastic sediment intercalated with calcite layers sediment erosion has also occurred allowing access to formerly sediment filled passages the palaeoenvironmental meaning and chronology of these three processes i e clastic sediment input clastic sediment erosion and speleothem precipitation were studied in both semi arid campo formoso and sub humid lagoa santa areas through 230 th dating and stratigraphical analyses the dry climate of the campo formoso area prevents speleothem deposition at present but soil erosion results in valley aggradation and cave infilling growth periods of speleothems and travertines in this area have allowed the recognition of recurrent past phases of increased humidity correlated with wet conditions recorded in southeastern brazil speleothem calcite at the lagoa santa area there is limited speleothem precipitation and sediment input at present however sediment entrainment is actively exhuming speleothems and exposing cave passages sediment erosion inside caves in the area is interpreted as being due to intermediate climatic conditions not wet enough to favour speleothem deposition and not too dry to allow doline slope erosion and sediment transport into caves due to the low rates of denudation and isostatic rebound inherent to tectonically stable areas cave passages will remain within the range of sediment infill and erosion for a much longer time than in tectonically active areas spanning in average at least three full glacial interglacial cycles as uplift proceeds cave passages will be decoupled from the doline bottom and no longer will be affected by erosion or infilling episodes sediment filled passages in many caves in the lagoa santa region are relict features that display ancient clastic and chemical precipitation the three processes described above have occurred throughout the life history of the caves resulting in complex sediment assemblages that can however show significant intra and inter site variations

stratigraphical and palaeontological data from the early pleistocene pirro 10 site of pirro nord puglia south eastern italy the pirro nord palaeontological and archaeological locality has been the object of recent field research to investigate the fossil content of its early pleistocene vertebrate palaeocommunities and to understand the genesis of the karst network and related deposits that delivered the lithic industry representing the earliest human occupation of europe known so far spanning 1 7e1 3 ma the succession of the pirro 10 site has been described in terms of facies and fossil vertebrate content of the 37 distinguished sedimentary units su on the whole the succession is made of chemical and clastic sediments that include debris fall and alluvial deposits su are distinguished according to lithology colour discontinuities lamination fossil concentration and taphonomical parameters palaeomagnetic data and biochronological characteristics refer the pirro 10 site to the latest late villafranchian mammal age of the italian biochronological mammal scale the fossil content is quite homogenous common taxa are axis eurygonos hystrix refossa ursus etruscus canis mosbachensis together with small mammal remains mainly represented by chiroptera and the arvicolid microtus allophaiomys e x gr ruffoi a significant change in the taxonomic record occurs in

ice sheet variability around the north atlantic ocean during the last deglaciation millennial scale variability in the flux of ice rafted detritus to north atlantic sediments during the last glacial period has been interpreted to reflect a climate forced increase in the discharge of icebergs from ice sheet margins surrounding the northern north atlantic ocean 1 but the relationship between ice sheet variability and climate change is not clear as both the sources of ice rafted detritus and the ice marginal processes are varied and complex 2 4 terrestrial records are helpful in unravelling this complexity because they can demonstrate the scale of ice sheet oscillations and whether the ice sheet or sector was advancing or retreating with respect to climate change here we constrain the age and anatomy of a prominent readvance of the british ice sheet in the northern irish sea region at similar to 14 14 c kyr bp similar to 16 4 calendar kyr bp the analysis indicates that the british ice sheet participated in an iceberg discharge episode known as heinrich event 1 comparison with other terrestrial and marine ice sheet records suggests that the dynamic collapse of the laurentide ice sheet beginning at 14 6 15 0 c 14 kyr bp1 4 similar to 17 2 17 6 calendar kyr bp 5 initiated varied responses from other ice sheet margins around the northern north atlantic region these observations support the argument that the release of icebergs and meltwater during heinrich event 1 disrupted the north atlantic thermohaline circulation 6 8 leading to a delay or reversal of deglaciation of the northern hemisphere and at least as far south as 40 degrees s for two to three thousand years 5 9 10 suggesting a climate forcing and response similar to that of the ensuing younger dryas cold snap 11 12

late quaternary evolution and sea level history of a glaciated marine embayment bantry bay sw ireland ireland experienced a spatially complex pattern of relative sea level rsl changes and shoreline development caused by the interplay of isostatic and eustatic ice equivalent sea level processes since the last glacial maximum lgm using a combination of high resolution marine geophysical data vibrocores foraminiferal analysis and 10 ams radiocarbon dates we reconstruct the late quaternary evolution and rsl history of bantry bay a large 40 km long 5 10 km wide embayment in sw ireland the data indicate two infill phases one before and one after the lgm separated by glacial and lowstand sediments the pre lgm history is not dated and the depositional history is inferred a large sediment lobe formed at the outer edge of bantry bay as a lowstand ice proximal glacimarine outwash system as the ice retreated after the lgm at a sea level ca 80 m lower than present iceberg scour immediately west of this location likely relate to the break up of the local kerry cork ice cap long curvilinear ridges seen both offshore and on top of the sediment lobe probably formed as shoreface ridges under stronger than present tidal currents during a period of rsl stability pre 14 6 ka cal bp a subsequent infill phase is characterised by a basin wide erosional ravinement surface and the deposition of inter and sub tidal estuarine sediments although our data support the general trends our stratigraphic and radiocarbon data suggest a higher sea level between 11 and 13 5 ka cal bp than predicted by existing glacial isostatic adjustment models

evaluation of a numerical model of the british irish ice sheet using relative sea level data implications for the interpretation of trimline observations the glacial isostatic adjustment gia of the british isles is complex due to the interplay between local and non local signals a number of recent studies have modelled the gia response of the british isles using relative sea level data this study extends these previous analyses by using output from a numerical glaciological model as input to a gia model this is a necessary step towards more realistic gia models and although there have been similar studies for the major late pleistocene ice sheets this is the first study to do so for the british isles we test three reconstructions classed as minimal median and maximal in terms of their volume at maximum extent and find it is possible to obtain good data model fits the minimal reconstruction is clearly preferred by the sea level data the ice reconstructions tested were not constrained by geomorphological information of past ice extent lateral and vertical as a consequence the reconstructions extend further than much of this information suggests particularly in terms of ice thickness it is notable however that the reconstructions produce good fits to many sea level data from central mountainous regions e g scottish highlands which lends support to the suggestion that trimlines often used as an constraint on the palaeo ice surface location are in fact features formed at the transition from warm to cold based ice and so mark a minimum constraint on the ice surface altitude based on data model misfits suggestions are made for improving the ice model reconstructions however in many locations the cause of the misfit could be due to non local predominantly fennoscandian ice and so interpretation is not straightforward as a result we suggest that future analyses of this type consider models and observations for both fennoscandia and the british isles copyright 2012 john wiley sons ltd

a new record of a scelidotheriine ground sloth xenarthra mylodontidae from central brazil quaternary cave stratigraphy taxonomy and stable isotopes abstract an upper fourth molariform of a scelidotheriine ground sloth is reported from carneiro cave which is located in the karstic region of serra da mesa goias in this limestone cave the tooth was found at the base of a depositional sequence associated with a 2 m thick debris flows deposit which is covered by the lowest carbonate crust dated at approximately 200 000 yr bp detailed morphological description stable isotope data and stratigraphic context are provided this represents the first megafauna record for this region of central brazil where this record is found in direct association with a diverse microvertebrate fauna

the age of the air in the firn and the ice at summit greenland in the framework of the eurocore drilling project 1989 at summit central greenland air samples were collected from a drill hole in the firn at several depth levels the samples have been analyzed for 85kr co2 ch4 cfc s f 11 and f 12 contents and for the isotopic composition of nitrogen and oxygen the measured data are compared with the results of a diffusion model co2 for example takes 12 years with a standard deviation of 7 5 years to diffuse from the surface to the firn ice transition under the present climatic conditions at summit the difference between the age of the ice and the mean age of the occluded air is approximately 210 years an enrichment of the heavier isotopes due to separation by gravity has been observed molecular diffusion alone suffices to explain the observed concentration trends in the firn column we can however not exclude the existence of a convective zone below the surface we have also measured the density and closed porosity along the firn core that has been retrieved when drilling the hole the porosity data reveal that the air is occluded into bubbles mainly between 65 and 80 m corresponding to densities of 790 and 830 kg m3 respectively

high precision 14c measurements demonstrate production of in situ cosmogenic 14ch4 and rapid loss of in situ cosmogenic 14co in shallow greenland firn abstract measurements of radiocarbon 14 c in carbon dioxide co 2 methane ch 4 and carbon monoxide co from glacial ice are potentially useful for absolute dating of ice cores studies of the past atmospheric ch 4 budget and for reconstructing the past cosmic ray flux and solar activity interpretation of 14 c signals in ice is complicated by the fact that the two major 14 c components trapped atmospheric and in situ cosmogenic are present in a combined form as well as by a very limited understanding of the in situ component this study measured 14 ch 4 and 14 co content in glacial firn with unprecedented precision to advance understanding of the in situ 14 c component 14 ch 4 and 14 co were melt extracted on site at summit greenland from three very large 1000 kg each replicate samples of firn that spanned a depth range of 3 6 5 6 m non cosmogenic 14 c contributions were carefully characterized through simulated extractions and a suite of supporting measurements in situ cosmogenic 14 co was quantified to better than 0 6 molecules g 1 ice improving on the precision of the best prior ice 14 co measurements by an order of magnitude the 14 co measurements indicate that most 99 of the in situ cosmogenic 14 c is rapidly lost from shallow summit firn to the atmosphere despite this rapid 14 c loss our measurements successfully quantified 14 ch 4 in the retained fraction of cosmogenic 14 c to 0 01 molecules g 1 ice or better and demonstrate for the first time that a significant amount of 14 ch 4 is produced by cosmic rays in natural ice this conclusion increases the confidence in the results of an earlier study that used measurements of 14 ch 4 in glacial ice to show that wetlands were the likely main driver of the large and rapid atmospheric ch 4 increase approximately 11 6 kyr ago

identification and importance of critical depositional gaps in pitfall cave environments the fossiliferous deposit of cuvieri cave eastern brazil abstract the majority of extinct brazilian late quaternary mammal i e megafauna remains comes from cave deposits and was retrieved through excavations lacking detailed stratigraphical context this poses a major problem since these deposits present multifaceted processes of formation based on the meticulous excavation of a pitfall site within cuvieri cave minas gerais eastern brazil this article describes a critical albeit subtle temporal discontinuity between different fossiliferous sedimentary facies and discusses its significance to the contextualization of the paleontological remains recovered from the site the discontinuity was described based on sedimentary analyses bone deposition processes taxonomy and ams radiocarbon chronology two facies were distinguished and named according to their color and texture an upper dark brown silt loam bsl and a lower dark reddish brown silt loam rbsl besides color differences they present differences in grain size distribution and chemical composition these analyses show that the rbsl has in its composition only half the sand and one third more the silt than bsl it also shows that mean percent values for the rbsl in comparison to the bsl are higher for silica 42 35 versus 15 80 aluminum 18 63 versus 7 58 and iron 8 45 versus 3 79 and lower for calcium 10 07 versus 36 14 and volatiles 13 86 versus 30 10 these differences are attributed to changes in sediment source and entrance route differences were also observed in the faunal remain analyses rbsl has abundant megafauna remains originally deposited within this facies while the scarce megafauna material found in bsl is the result of mixing processes despite these differences animal entrapment is considered the best scenario to explain bone accumulation in both facies ams radiocarbon dates indicate that the bsl was deposited during the holocene with dates ranging from 8580 cal yr bp to the present while the rbsl deposition dates to the holocene pleistocene transition 13 600 10 660 cal yr bp radiocarbon dating also indicates that the subtle erosional surface that limits both facies represents a temporal gap between a minimum age of 8 4 cal kyr bp and a maximum age of 11 0 cal kyr bp the recognition of this discontinuity allows for a more accurate interpretation of bone accumulation enabling the differentiation of faunal assemblages that might otherwise be considered part of a continuum

late quaternary sea level change and evolution of belfast lough northern ireland new offshore evidence and implications for sea level reconstruction the interplay of eustatic and isostatic factors causes complex relative sea level rsl histories particularly in paraglacial settings in this context the past record of rsl is important in understanding ice sheet history earth rheology and resulting glacio isostatic adjustment field data to develop sea level reconstructions are often limited to shallow depths and uncertainty exists as to the veracity of modelled sea level curves we use seismic stratigraphy 39 vibrocores and 26 radiocarbon dates to investigate the deglacial history of belfast lough northern ireland and reconstruct past rsl a typical sequence of till glacimarine and holocene sediments is preserved two sea level lowstands both max 40 m are recorded at c 13 5 and 11 5k cal a bp each is followed by a rapid transgression and subsequent periods of rsl stability the first transgression coincides temporally with a late stage of meltwater pulse 1a and the rsl stability occurred between c 13 0 and c 12 2k cal a bp younger dryas the second still slowstand occurred between c 10 3 and c 11 5k cal a bp our data provide constraints on the direction and timing of rsl change during deglaciation application of the depth of closure concept adds an error term to sea level reconstructions based on seismic stratigraphic reconstructions

submerged early holocene coastal and terrestrial landforms on the inner shelves of atlantic canada coastal and terrestrial landforms that formed with lowered relative sea levels during the early postglacial period in atlantic canada were submerged during the holocene transgression however these landforms are seldom seen on sea floor imagery factors that contribute to their destruction include the brevity of sea level lowstands and high wave energy on shallow modern shelves we identify one situation within which preservation has been relatively good large coastal lakes that existed for many thousands of years before being connected to the ocean by rising sea level in the mid holocene we describe bedford basin near halifax nova scotia and deal more exhaustively with the bras d or lakes an inland sea in cape breton nova scotia the preservation of shore platforms barrier beaches and spits and fluvial systems was due to the rapid onset of the transgression and the relatively low wave energy in the subsequent marine phases the well preserved early holocene coastlines are highly favourable targets in the search for evidence of human occupation in the early to mid holocene

growth and decay of a marine terminating sector of the last british irish ice sheet a geomorphological reconstruction the boundary conditions that govern ice sheet dynamics can change significantly with the development of marine margins this paper uses the glacial landscape in western scotland to reconstruct changes in the british irish ice sheet that accompanied the growth and decay of a marine sector over the malin shelf ice advanced from a restricted mountain ice sheet with tidewater margins after 35 ka bp and reached the continental shelf in 7 ka average rate of 30 m a 1 early ice flow had been directed through north south geologically controlled over deepened fjords that were carved during previous restricted glaciations this flow regime was abandoned with development of the malin shelf ice sheet sector ice flow direction switched by 90 degrees and was drawn westwards towards the shelf edge the marine ice sheet phase saw episodes of west east ice divide migration by up to 60 km over west central scotland possibly linked to ice streaming and calving events at the ice sheet margin however permanent and stationary ice divides and zones of cold based ice associated with subglacial topographic highs also characterised the marine glacial stage over western scotland the north channel ice divide remained a constant though migratory feature while the biis occupied the malin shelf it finally collapsed at the end of the killard point stadial when the irish ice sheet began to rapidly decay 16 5 ka bp this permitted the scottish ice sheet to temporarily advance over north east ireland previously identified as the east antrim coastal readvance before it too retreated at rates in the order of 10 2 m a 1 although the imprint of extensive shelf edge ice sheet glaciation exists in the coastal landscape of western scotland the dominant landscape features relate to a restricted marine proximal mountain ice sheet with markedly different flow configurations similar first order geomorphological features relating to restricted glacial conditions are likely to be preserved in subglacial highlands under interior parts of modern ice sheets

the 14c bomb spike determines the age spread and age of co2 in law dome firn and ice we report a precise model independent determination of the age and age spread of co2 in air trapped in ice a large pulse of atmospheric radiocarbon generated in the atmosphere by nuclear tests peaked in the early to mid 1960 s we measure the profile of the radiocarbon bomb spike in firn air and ice bubbles from high snow accumulation sites drilled in 1987 and 1993 on law dome east antarctica by employing high precision ams accelerator mass spectrometry large 14c atmospheric growth rates and a high signal to noise ratio lead to a direct and precise determination of the co2 age and age spread in the ice a least squares comparison with the atmospheric history gives a mean co2 age of 8 9 0 5 years at the bottom of the firn where vertical gas diffusion ceases with an age spread in the ice full width of a moving average smoothing window of 12 5 1 5 years these results confirm the possibility of examining decadal trace gas variations prior to direct instrumental measurements

megafauna from the late pleistocene holocene deposits of the upper ribeira karst area southeast brazil abstract the carbonate caves of the upper ribeira valley southeastern sao paulo state brazil preserve an abundant fossil record of pleistocene holocene south american megafauna nevertheless in comparison with other localities of the country its paleontological knowledge still can be considered sparse and in need of further research this work presents an update taxonomic survey of the megafauna material collected since the beginning of the explorations in the area based on this it discusses paleobiogeographic and paleoecological questions the fossil megafauna of the upper ribeira karst region include eremotherium laurillardi nothrotherium maquinense lestodon armatus catonyx cuvieri ocnopus gracilis ahytherium aff aureum glyptodon clavipes g reticulatus hoplophorus cf toxodon spp stegomastodon waringi equidae hippidion cf tapirus terrestris panthera onca and smilodon populator only p onca and t terrestris still remain in the region despite the occurrence of some typical taxa of the pampean paleobiogeographical province the fossil assemblage recorded shows greater affinity to the mega mammal community of the intertropical region the ecology of species found suggests the previous occurrence of fairly different environmental settings than the existing one in the area there were more temperate climates both dry and wet until the current mesophytic forest was finally established the studied material does not show any kind of chrono correlation given the type of genesis of the cave accumulations these fossils depict different faunistic moments related to climate changes during the quaternary to better understand the information provided by these deposits efforts on dating and detailed taphonomic investigations should be conducted the studies of the quaternary fauna in the state of sao paulo fill an important gap in the intricate biogeographical history of the south american megafauna

sea level change and inner shelf stratigraphy off northern ireland new seismic stratigraphic vibracore and ams c 14 dates from two sites off the northern ireland coast yield information on the deglacial to present sea level history and shelf evolution of the region a lowstand of sea level at about 30 m below present sea level recorded by fossils in a lowstand shoreline deposit occurred around 13 4 cal ka b p following a period of rapid isostatic uplift associated with a rsl fall of 6 7 cm yr following the lowstand contrasting styles of sedimentation characterized the two study sites in the sheltered environment of belfast lough the lowstand shoreline was overtopped and buried by transgressive facies of intertidal and shallow sub tidal mud and sandy mud on the high energy portrush coast the inner shelf sedimentary sequence is characterized by a basal conglomerate overlain by well sorted sands with occasional interbedded gravel c 2006 elsevier b v all rights reserved

stratigraphic evolution of the inner continental shelf in response to late quaternary relative sea level change northwestern gulf of maine accumulations of deltaic and littoral sediments on the inner continental shelf of maine gulf of maine preserve a record of postglacial sea level changes and shoreline migrations the depositional response of coastal environments to a cycle of regression lowstand and transgression was examined with seismic reflection profiles vibracores and radiocarbon dates collected from sediments at the mouths of the kennebec and penobscot rivers sequence stratigraphic analysis of these data reveals two distinctly different successions of late quaternary deposits that represent end members in an evolutionary model for this glaciated coast seaward of the kennebec river coarse grained shorelines with foreset beds occur at depths of 20 60 m and outline the lobate margin of the kennebec river paleodelta a complex rock framed accumulation of glaciomarine and deltaic sediments capped by estuarine and marine deposits sand derived from this system today supports large barrier spits and extensive salt marshes in contrast the mouth of the penobscot river is characterized by thick deposits of glaciomarine mud overlain by marine mud of holocene age including gas charged zones that have locally evolved into fields of pockmarks the distinct lack of sand and gravel seaward of the penobscot river and its abundance seaward of the kennebec river probably reflect differences in sediment sources and the physiography of the two watersheds the contrasting stratigraphic framework of these systems demonstrates the importance of understanding local and regional differences in sediment supply sea level change bedrock structure and exposure to waves and tides in order to model river mouth deposition on glaciated coasts evolution of shelf deposits was largely controlled by relative sea level which locally fell from a highstand 60 to 70 m at 14 ka contemporary with deglaciation to a lowstand 55 m at 10 8 ka the sea level lowering was accompanied by fluvial incision of older deposits producing a regressive basal unconformity major rivers deposited abundant sediment over this surface sea level then rose at varying rates extensively reworking formerly emergent parts of the shelf and producing a shoreface ravinement surface in areas exposed to waves a tidal ravinement surface has developed in sheltered embayments where erosion is due mainly to tidal currents incised valleys in both settings preserve transgressive estuarine deposits that contain lagoonal bivalves and salt marsh foraminifera at depths of 15 30 m these deposits accumulated ca 9 2 7 3 ka locally a period of relatively slow sea level rise

reconstructing diagenetic conditions of bone at the gray fossil site tennessee usa abstract the preservation of vertebrate fossils requires transformation of the original bioapatite mineral matrix predominantly hydroxylapatite during diagenesis into a thermodynamically more stable phase fossil bone geochemistry and structure provides a wealth of information on the conditions present during diagenesis including site redox and ph and about sedimentation rates during burial the gray fossil site preserves late neogene lacustrine deposits that serve as one of a few records of north american paleoclimate during a critical period of the cenozoic despite having 40 vertebrate species and diverse plant assemblages none of the prior studies used bone composition to understand what paleoenvironmental and diagenetic conditions must have been like to facilitate bone preservation and fossilization alligator sp phalanges were examined using multiple geochemical tools including fourier transform infrared spectroscopy x ray diffraction and electron microprobe analyses evidence of bioerosion within thin cortical and isolated trabecular regions of bone suggests biotic utilization of organics collagen and or the mineral s following deposition chemically zoned and laminated cortical alligator bone is interpreted as preserved lines of arrested growth that developed during life and supports previous interpretations of a regional seasonal climate lastly the alligator bones are mineralogically heterogeneous as fluorinated and iron containing apatite phases compared to modern bone iron concentrations were high at up to 3 wt the uptake of fe by the alligator bones examined in this study suggests that fluids present during diagenesis that led to bone preservation within the lacustrine sediment at the gray fossil site were likely acidic anoxic and reducing

extended range luminescence chronologies suggest potentially complex bone accumulation histories at the early to middle pleistocene palaeontological site of huescar 1 guadix baza basin spain abstract the palaeontological site of huescar 1 contains a diverse faunal assemblage and has played an important role in establishing local scale biozone successions in the guadix baza basin here we provide the first ages for the fossil bearing deposits at this site using a suite of extended range luminescence dating approaches including optically stimulated luminescence osl of quartz supergrains multi grain and single grain thermally transferred osl of quartz and post infrared infrared stimulated luminescence of k feldspars assessments of luminescence characteristics and laboratory quality assurance tests indicate that the huescar 1 sediments are well suited for extended range dating applications and the resultant chronologies obtained using different luminescence approaches display a high degree of consistency our combined luminescence ages reveal that the fossil bearing fluvial sediments at this marginal lacustrine site were deposited 420 460 ka or possibly 420 570 ka which is younger than some of the tentative late early to early middle pleistocene ages inferred from faunal associations comparison of the dating results with taphonomic taxonomic and geomorphic evidence suggests that the site may preserve an admixture of bones in primary depositional context and reworked fossils sourced from potentially older deposits in the surrounding valley as such the luminescence ages obtained for the host sediments may not be contemporaneous with all of the faunal remains preserved at huescar 1

comments on an anthropogenic modification in an eremotherium tooth from northeastern brazil over150yearsago peterw lundproposedthatlatequaternaryextinct megafauna henceforth just megafauna and homo sapienscoexisted in brazil lund 1844 but only recently his hypothesiswas supported by direct radiocarbon dating on megafauna bones neves and pilo 2003 hubbe et al 2007 2009 2011 these datesshowed that in some brazilian regions at least some speciessurvived until the beginning of the holocene and became extinctafter the arrival of the rst human groups besides the chronolog ical evidence which indicates that humans and megafauna lived inthe same region at the same time there are also claims that theymayhaveinteractedmoreactivelybasedonthe ndingofsingle orvery few bones or bone fragments associated with human occu pation levels near archeological material or showing marks thatsuggest their usage by humans however based on the meticulousrevision provided by prous 2002 it is possible to rule out most ofthese cases due to theircontroversial nature in fact few of those ifany can be held as solid evidence of this close interaction notconsidering scavengingon bones from a long ago deceased animal prous and fogaca 1999 recently dantas et al in press reported the nding of a singletooth fragment of the ground sloth eremotherium in sergipe state northeastern brazil that according to the authors presentsanthropogenic marks that favor the coexistence of this species andh sapiens however in our opinion their work does not providesolid evidence of an interaction of this nature and therefore theaim of this comment is to discuss the validity of their nding asreliable evidence of megafauna more speci cally eremotherium and humans coexistence in sergipe the coexistence and notablythe close interaction between the former and the later may haveimportant implications to the understanding of the initial humanoccupation of south america hence this kind of nding should notbe taken as granted but rather should be analyzed with rigorouscriteria in the following comments we question the interpretationof the marks seen in the tooth as human made cutmarks based on1 thenatureandlocationofthecutmarksand2 thearchaeologicalandpaleontologicalcontextof the nding furthermore wediscussreasons why the conclusions based on this nding could beseverely distorted dantas et al in press 1 described the marks found on thereported tooth as an effort to build a triangular object based onthe material the location of the marks and the scant informationprovided e g it is notclear if morebones fromeremotheriumwerefound if there are more bones from other species with marks whichother species were found it is hardtoaccept that the marksobserved are the result of human intervention on the tooth themarks are described by dantas et al in press 1 as being humanbecause they have parallel grooved striations narrower anddeeper which follow the curvature of the tooth along apical andlateral borders unfortunately these characteristics are unclear tous in the pictures presented by the authors fig 2f shows onlystriations fig 2g appear to show microwear striations when thescaleofthephoto 0 1mm istakenintoaccount andfig 2hshowsa network of shallow striations that crisscross the surface in everydirection in summary it is not possible to see the diagnosticfeatures in the pictures presented by the authors to justify theirconclusions of an anthropogenic origin for them added to the diagnostic dif culties of the marks in this tooth their occurrence is not in accordance to the standard patternsobserved for food processing in ethnographic and archaeologicalcontexts e g walker 1978 lupo 2002 lyman 2005 martinez 2009 thus diminishing the possibility of butchering marks onthis tooth indeed dantas et al in press never claimed thesemarks were the result of butchering however it is very hard to

natural and anthropogenic changes in atmospheric co2 over the last 1000 years from air in antarctic ice and firn a record of atmospheric co2 mixing ratios from 1006 a d to 1978 a d has been produced by analysing the air enclosed in three ice cores from law dome antarctica the enclosed air has unparalleled age resolution and extends into recent decades because of the high rate of snow accumulation at the ice core sites the co2 data overlap with the record from direct atmospheric measurements for up to 20 years the effects of diffusion in the firn on the co2 mixing ratio and age of the ice core air were determined by analyzing air sampled from the surface down to the bubble close off depth the uncertainty of the ice core co2 mixing ratios is 1 2 ppm 1 preindustrial co2 mixing ratios were in the range 275 284 ppm with the lower levels during 1550 1800 a d probably as a result of colder global climate natural co2 variations of this magnitude make it inappropriate to refer to a single preindustrial co2 level major co2 growth occurred over the industrial period except during 1935 1945 a d when co2 mixing ratios stabilized or decreased slightly probably as a result of natural variations of the carbon cycle on a decadal timescale

the 18o isotope exchange rate between firn air co2 and the firn matrix at three antarctic sites 1 having measured 18o of firn air co2 for three antarctic sites dronning maud land dome concordia and berkner island we established that at depth the 18o co2 values are systematically shifted away from atmospheric values toward isotope equilibrium with h2o from precipitation firn matrix the 18o co2 shifts increase with depth and thus with co2 age the equation of a first order reaction is used to describe and calculate co2 oxygen isotope exchange rates the calculated exchange rates clearly show a correlation with firn temperatures assuming that the same mechanism operates at different sites and at different temperatures a pseudoactivation energy of 7 8 0 8 kcal mol is estimated the occurrence of exchange means that firn is not chemically inert in that sense that some form of co2 hydration takes place possible mechanisms of co2 oxygen isotope exchange are discussed and liquid like layers on firn grains are the most likely interface where this exchange takes place other gases e g cos may likewise be sensitive to hydration or related reactions and this may reduce their integrity in firn a formal translation of the reaction rates of co2 oxygen isotope exchange in firn to a cos hydration rate appears to indicate cos preservation on the scale of tens of thousands of years we suggest that the value of co2 oxygen exchange rate in firn expressed as half reaction time t may be used as a new firn characteristic giving a measure of hydration activity in firn an indirect measure of firn metamorphism and be correlated with other firn processes near a pore close off depth t values may possibly correlate with the process of he and ne diffusion expulsion during the close off of pores in firn as well as the release of 14co produced in situ in the firn matrix

a new greenland ice core chronology for the last glacial termination 1 we present a new common stratigraphic timescale for the north greenland ice core project ngrip and grip ice cores the timescale covers the period 7 9 14 8 kyr before present and includes the bolling allerod younger dryas and early holocene periods we use a combination of new and previously published data the most prominent being new high resolution continuous flow analysis cfa impurity records from the ngrip ice core several investigators have identified and counted annual layers using a multiparameter approach and the maximum counting error is estimated to be up to 2 in the holocene part and about 3 for the older parts these counting error estimates reflect the number of annual layers that were hard to interpret but not a possible bias in the set of rules used for annual layer identification as the grip and ngrip ice cores are not optimal for annual layer counting in the middle and late holocene the timescale is tied to a prominent volcanic event inside the 8 2 kyr cold event recently dated in the dye 3 ice core to 8236 years before a d 2000 b2k with a maximum counting error of 47 years the new timescale dates the younger dryas preboreal transition to 11 703 b2k which is 100 150 years older than according to the present grip and ngrip timescales the age of the transition matches the gisp2 timescale within a few years but viewed over the entire 7 9 14 8 kyr section there are significant differences between the new timescale and the gisp2 timescale the transition from the glacial into the bolling interstadial is dated to 14 692 b2k the presented timescale is a part of a new greenland ice core chronology common to the dye 3 grip and ngrip ice cores named the greenland ice core chronology 2005 gicc05 the annual layer thicknesses are observed to be log normally distributed with good approximation and compared to the early holocene the mean accumulation rates in the younger dryas and bolling periods are found to be 47 2 and 88 2 respectively

insights into holocene megafauna survival and extinction in southeastern brazil from new ams 14 c dates abstract the extinction of late quaternary megafauna in south america has been extensively debated in past decades the majority of the hypotheses explaining this phenomenon argue that the extinction was the result of human activities environmental changes or even synergism between the two although still limited a good chronological framework is imperative to discuss the plausibility of the available hypotheses here we present six new direct ams 14 c radiocarbon dates from the state of sao paulo brazil to further characterize the chronological distribution of extinct fauna in this part of south america the new dates make evident that ground sloths toxodonts and saber toothed cats lived in the region around the pleistocene holocene transition and in agreement with previous studies also suggest an early holocene survival for the ground sloth catonyx cuvieri taken together with local paleoclimatic and archaeological data the new dates do not support hunting or indirect human activities as a major cause for megafauna extinction although more data are required parsimony suggests that climatic changes played a major role in this extinction event

u series dating and taphonomy of quaternary vertebrates from brazilian caves abstract the geochronology and taphonomy of internationally important fossil bearing cave deposits were studied both in the semi arid northern bahia area and the subtropical southeastern lagoa santa area of brazil taphonomic analysis suggests that the processes responsible for bone accumulation in the brazilian caves vary between sites and taphonomic bias can therefore be significant in causing differences in faunal composition in the toca da boa vista caves the presence of single articulated skeletons and the entrance related distribution indicate that random penetration of animals is the main mechanism of fossil accumulation a process that biases the assemblage to smaller species and takes place over extended time periods in nearby toca dos ossos cave transport by runoff in the cave river is predominant and biases the fauna remains to larger more robust bones and species deposition probably also occurred only at times of enhanced runoff giving a more contemporaneous assemblage similar processes were responsible for emplacement of the copious fossil remains in the more humid lagoa santa area where terrigenous fossil deposits are found intercalated by massive speleothem calcite layers in this area runoff under a drier climate probably accounts for the sediment emplacement inside caves in both areas the mode of emplacement implies bias in the fossil record resulting in fossil assemblages that do not mirror surface faunas limiting palaeoenvironmental reconstruction mass spectrometric u series analysis of speleothem calcite overlaying fossil remains gives minimum ages for fossil deposition these ages confirm the previous view that many of the deposits derive from the late glacial but also show that much older material some 350 000 yr is also present the habitat requirements of critical fossil species such as bats and monkeys strongly suggest that they derive from much wetter periods when forest cover was present in the currently semi arid northern bahia area taphonomy exerts a major control on the diversity and mode of emplacement of cave fossil deposits in eastern brazil and thus detailed sedimentological and hydrological studies coupled with a sound geochronological approach are essential in quantifying the relative importance of each taphonomic processes before faunal and palaeoecological interpretations can be attempted

geomorphic and stratigraphic signals of postglacial meltwater pulses on continental shelves selective development and preservation of major shoreline complexes on the continental shelf provide geomorphic evidence in support of alternating periods of holocene sea level stillstand and rapid rise during meltwater pulses on a tectonically stable far fi eld setting the southeast african shelf regionally developed well preserved shoreline complexes occur at 100 m and 60 m within an overall shelf sequence dominated by transgressive ravinement non preservation of shorelines the development of geomorphically mature submerged shorelines with equilibrium forms is attributed to extended periods of sea level stability and their preservation is the result of early cementation followed by very rapid sea level rise several centimeters per year that caused overstepping meltwater pulses 1a and 1b are recorded in the shelf stratigraphy and geomorphology setting aside local infl uences of topography and sediment supply we hypothesize that shelf stratigraphies should preferentially preserve shorelines at water depths associated with the stillstands or slowstands immediately preceding meltwater pulses a reappraisal of shelf stratigraphy and geomorphology in particular the preservation potential of former shorelines is required in the light of contemporary understanding of postglacial sea level history

local scale proxy evidence for the presence of closed canopy forest in north western borneo in the late pleistocene bones of strategy i bats from the archaeological record of the great cave of niah sarawak abstract the limits of the distribution of closed canopy forest in southeast asia during the glacial cycles of the pleistocene are the subject of continuing debate in this context this paper reports the results of an analysis of a novel line of evidence as a local scale case study 22 dated assemblages of bat bones that were recovered from the archaeological sequences of the great cave of niah in sarawak malaysian borneo were examined by examination of the morphological characteristics of the distal articulation of the humerus seven families and nine genera were identified five species level attributions could be made these assemblages formed a time series of 14 chronological intervals 48 0 35 ky bp ky bp 103 calibrated years before present 1950 incorporating samples from the high glacial interval 26 18 ky bp and last glacial maximum 23 19 ky bp bones of bat taxa that are adapted to forage in the cluttered environments in the interior of closed canopy forest strategy i bats were employed as proxy evidence for the presence of closed canopy forested habitats in the vicinity bones of strategy i bats principally small hipposideros spp were identified in all examined assemblages and intervals in the time series statistical testing indicated no evidence of differences in the absolute frequency of distal humeri from strategy i bats in the pleistocene samples 48 11 8 ky bp or in the entire time series 48 0 35 ky bp and no significant linear trend was found in the time series to suggest an increase of the bones strategy i bat taxa with the onset of the holocene these findings suggest that closed canopy forest habitats have been a persistent component in the landscape around the great cave of niah since 48 ky bp a taphonomic hypothesis is proposed to explain the dichotomy between the findings of this study and the pollen record of the site

the brazilian megamastofauna of the pleistocene holocene transition and its relationship with the early human settlement of the continent abstract one of the most intriguing questions regarding the brazilian late quaternary extinct megafauna and homo sapiens is to what extent they coexisted and how humans could have contributed to the former s extinction the aim of this article is to review the chronological and archaeological evidences of their coexistence in brazil and to evaluate the degree of direct interaction between them critical assessment of the brazilian megafauna chronological data shows that several of the late pleistoscene early holocene dates available so far cannot be considered reliable but the few that do suggest that at least two species catonyx cuvieri ground sloth smilodon populator saber toothed cat survived until the beginning of the holocene in southeast brazil archaeological data indicates that the first human groups arrived in brazil and were inhabiting this region during the last millennia of the pleistocene and consequently they coexisted with the extinct fauna in some parts of brazil for at least one thousand years there is no robust evidence favoring any kind of direct interaction between humans and megafauna prior to their extinction to date it is not possible to properly judge the indirect influence of humans landscape transformation introduction of predators among others in this extinction event intense and to some extent unique climate changes between the last glacial maximum and the holocene favors the interpretation that they had a major contribution to the megafauna extinction although the scarcity of data impedes the proper testing of this hypothesis

missing records and depositional breaks in french late pleistocene cave sediments abstract cave entrance and rock shelter infillings are positioned within the pleistocene chronology for three areas of france northern alps franche comte and perigord despite minor local variations it is possible to identify regional types with a consistent depositional record over long intervals of time the interregional variability relates to the frequency and position of the gaps within the infillings sites in the northern alps have not yielded any artifacts older than the upper paleolithic magdalenian and dated sedimentary sequences do not go back beyond the older dryas more complete sequences in franche comte contain mousterian industries two major gaps occur here one lasting about 50 000 yr during the lower glacial and lower pleniglacial periods and the other lasting some 10 000 yr during the upper pleniglacial the sequences are more complete in the perigord where all major climatic phases have been identified with no significant sedimentary gaps differences in sedimentary records can be explained by variations in regional conditions during the last interglacial glacial cycle and especially by the distance from the maximum advance of ice daring glaciation

vertebrate taphonomy and paleoecology in an upper pleistocene tank deposit of paraiba brazil taphonomic modes evidence of temporal and spatial resolutions and paleoecological patterns of the brazilian intertropical region abstract curimatas paleontological site cps preserved one of the most iconic fossil assemblages of late pleistocene vertebrates of brazil fossils were collected in a tank deposit a singular type of quaternary vertebrate bearing deposit of south america in this work a detailed taphonomic study of the tank assemblage of cps is presented this analysis also provides taphonomic and paleoecological data obtained through the application of common multivariate techniques and provides estimates of time and spatial resolution for tank deposits the results show that although the cps assemblage has experienced an array of taphonomic processes the long distance transport was the main process controlling the taphonomic pathway of the thanatocoenosis during the biostratinomic phase and was responsible for the co occurrence of other processes such as abrasion fragmentation and bioclastic sorting the origin of the taphonomic modes of vertebrates in the tank deposit of cps may have been controlled by three major taphonomic phenomena i a taphonomic bias towards the large bodied size ii long time span of transportation towards the final burial environment and iii some degree of reworking furthermore the analysis of these taphonomic modes supports a previous hypothesis although taphonomic biases affect the origin of tank assemblages paleoecological patterns can be preserved with considerable fidelity the time resolution in tank accumulations is of the order of 10 3 to 104 years and their spatial resolution seems to be from local to regional

a key site for inferring the timing of dispersal of giant deer in sardinia the su fossu de cannas cave sadali italy abstract su fossu de cannas sfc cave is one of several known cavities in the sadali plateau in sardinia italy the evolution of the cave is the result of complex erosional and deposital processes that occurred during the neogene and quaternary a fossiliferous cemented conglomerate containing various deer remains now forms the ceiling of a cavity tunnel the faunal remains belong to a large cervid which show some morphological affinity with large deer that have an endemic sardinian lineage praemegaceros sardous praemegaceros cazioti palaeoecological data based on some peculiar features and the large size of the sfc deer suggest that it is the most primitive megacerine found in sardinia to date and the first representative of the endemic lineage the 450 ka u th age for the flowstone capping the fossiliferous layer defines the end of sedimentation in which sadali deer remains are preserved and the dispersal from the mainland of the ancestor of the endemic sardinian megacerini stratigraphic and micromorphological analyses of the cave deposits allow the reconstruction of the timing of the cave s development throughout the pliocene to the holocene

the dominance of an extant gregarious taxon in an attritional accumulation taphonomy and palaeoecological implications abstract a recurrent aspect of the fossil record is the observation of a disproportionate number of specimens or individuals of a single taxon in some deposits which is stated as dominance commonly the dominance is explained as the result of catastrophic or short term mass death events or are proxies for palaeoecological inferences regarding gregariousness however taphonomic stratigraphic and chronologic analyses of fossiliferous deposits have shown that this is not always true to contribute to the study of dominance in fossil assemblages we describe a probable quaternary skeletal accumulation dominated by the extant gregarious rock dwelling rodent kerodon rupestris recovered from sumidouro do sansao a 65 m deep pitfall cave in northeast brazil and discuss the palaeoecological implications of our findings we provide taxonomic identification taphonomic analyses and chronological assessment besides k rupestris minimum number of individuals mni 35 we recorded three taxonomic groups that are the ground sloth catonyx cuvieri mni 1 the anteater tamandua tetradactyla mni 1 and the cougar puma concolor mni 1 the taphonomic analysis of the k rupestris remains supports the idea that entrapment of individuals was the main process of bone accumulation and that the death of cave inhabitants followed by short transport to the main hall possibly occurred kerodon rupestris remains persisted on the surface of the cave deposit for different time spans and were exposed to fragmentation weathering invertebrate boring and encrustation inside the cave environment direct dating suggests differences in the ages obtained and intermittent deposition of the individuals inside the cave it highlights the influence of taphonomic controls on gregarious taxa such as k rupestris towards dominating attritional time averaged assemblages furthermore it demonstrates that such assemblages do not necessarily support inferences about single event mortality and gregariousness of the dominant taxon

uranium series chronology and environmental applications of speleothems an increasing number of scientists recognize the value of speleothems1 as often extremely well preserved archives of information about past climate vegetation hydrology sea level nuclide migration water rock interaction landscape evolution tectonics and human action well constrained data are required to document past changes reconstruct past patterns and predict future responses of the earth system at a wide range of spatial and temporal scales speleothems are particularly useful in this regard because they can be found in many locations of the globe sampled at high resolution and reliably dated using high precision uranium series techniques speleothems are bodies of mineral material formed in caves as the result of chemical precipitation from groundwater flowing or dripping in a cave most speleothems are composed of calcite formed by slow degassing of co2 from supersaturated groundwater but aragonite and gypsum forms are also common particularly near cave entrances where evaporative effects are important a host of different speleothem types decorate the walls ceilings and floors of caves and their mineralogy and morphology is a function of fluid flow and chemistry of waters feeding a particular location as well as the ambient conditions temperature chemistry light in the air or water filled void subaerial forms include the familiar stalagmites stalactites draperies flowstones subaqueous forms include rimstone pools rafts mammillary calcite wall coatings and dog tooth spar for an extensive review of the types of speleothem that have been observed see hill and forti 1997 speleothems are used in a multitude of ways to explore past environmental conditions perhaps the most fundamental of which is their very presence or absence deposition of speleothems relies on sufficient water supply and soil co2 to enable dissolution and transport of reactants in the vadose zone to underlying caves in arid or glacial times conditions may not have been favorable for speleothem formation

quaternary ecological and geomorphic changes associated with rainfall events in presently semi arid northeastern brazil several geomorphic features and palaeobiotic remains in now semi arid northeastern brazil indicate major palaeoenvironmental changes during past periods of increased rainfall 230th mass spectrometric ages of speleothems and travertines have allowed the determination of the timing and duration of wetter than present conditions the data demonstrate that wet events have occurred throughout much of the pleistocene present dry conditions having been established at the end of the younger dryas a markedly different fauna comprising megafaunal elements not adapted to the present low arboreal scrubland caatinga vegetation existed in the area palaeobotanical remains embedded in travertine indicate forested vegetation at these wetter intervals suggesting that the caatinga was then replaced or mixed with a semi deciduous forest due to the abundance of travertine sites containing fossil botanical remains in northeastern brazil it is believed that forest expansion occurred over large areas of the now semi arid zone showing that the long hypothesised forested links between biodiversity rich amazon and atlantic rainforests may indeed have existed during these moister phases copyright 2004 john wiley sons ltd

mid pleistocene cave fills megafaunal remains and climate change at naracoorte south australia towards a predictive model using u th dating of speleothems abstract the limestone caves of the naracoorte region in south australia contain extensive deposits of megafauna rich sediments and intercalated cave formation speleothems high precision thermal ionisation mass spectrometry tims u th dating of flowstones directly associated with several large deposits reveals a distinct cyclicity in the timing of sediment and flowstone depositional events in the naracoorte caves this pattern parallels a cyclical alternation of wet phases and intervening periods with a water deficit over the last 500 ka ayliffe et al 1998 geology 26 147 dates from flowstone interlayers in the fossil deposits coincide with the massive speleothem growth events which characterise wet phases hiatuses in flowstone deposition correlatable through several cave systems imply that water deficits were initiated by regional aridity during full glacial and then extended into the succeeding warmer wetter interglacials clastic deposits in caverns with restricted entrance shafts correlate with hiatuses suggesting many of these deposits contain fauna representative of full glacial and interglacial climates caverns with small openings have often been sealed from the surface and dating has constrained the length of accumulation episodes in several fossil deposits one to less than 20 ka the hydrological regimes and environmental conditions inferred from the timing of speleothem deposition have been used to develop a model for cyclic sediment and bone accumulation in the caverns at naracoorte over the last 400 ka the giant victoria fossil chamber deposit accumulated prior to 200 ka and because its entrance is large it may contain faunas representative of all climatic phases there has been no apparent change in faunal diversity at naracoorte over at least three glacial interglacial cycles of the middle pleistocene

isotopic paleoecology δ13c from mammals from iuiu ba and paleoenvironmental reconstruction δ13c δ18o for the brazilian intertropical region through the late pleistocene abstract stable isotopes of carbon and oxygen of fossil specimens are widely used for paleoecological and paleoenvironmental inferences and there has been an effort to better understand the isotopic paleoecology and chronology of herbivores that inhabited the brazilian intertropical region during the late quaternary in the present work new radiocarbon datings and carbon and oxygen isotopes data for eremotherium laurillardi notiomastodon platensis tapirus terrestris tayassu pecari and mazama gouazoubira are presented from specimens that lived on iuiu county toca fria and jatoba caves state of bahia in the brazilian intertropical region e laurillardi was dated as of 32 ka bp representing the oldest direct dating for this species in the brazilian intertropical region while n platensis was dated as of 25 ka bp fossils of the extant species t pecari m gouazoubira and t terrestris presented radiocarbon ages of 23 ka bp 21 ka bp and 15 ka bp respectively showing that some of these species lived in iuiu during the last glacial maximum according to our analyses t terrestris was the only specialist 13c 11 0 pic3 0 76 ba 0 49 whereas the remaining taxa were generalists mixed feeders 13c 1 3 to 10 0 pic3 0 24 to 0 69 ba 0 58 the paleoenvironment reconstruction in iuiu and other localities in bir during 32 ka bp to 15 ka bp allow us to suggest that the dry arboreal to open savanna habitats rich in grass and shrubs were the most common environment

a revised 1000 year atmospheric δ13c co2 record from law dome and south pole antarctica 1 we present new measurements of 13c of co2 extracted from a high resolution ice core from law dome east antarctica together with firn measurements performed at law dome and south pole covering the last 150 years our analysis is motivated by the need to better understand the role and feedback of the carbon c cycle in climate change by advances in measurement methods and by apparent anomalies when comparing ice core and firn air 13c records from law dome and south pole we demonstrate improved consistency between law dome ice south pole firn and the cape grim tasmania atmospheric 13c data providing evidence that our new record reliably extends direct atmospheric measurements back in time we also show a revised version of early 13c measurements covering the last 1000 years with a mean preindustrial level of 6 50 finally we use a kalman filter double deconvolution to infer net natural co2 fluxes between atmosphere ocean and land which cause small 13c deviations from the predominant anthropogenically induced 13c decrease the main features found from the previous 13c record are confirmed including the ocean as the dominant cause for the 1940 a d co2 leveling our new record provides a solid basis for future investigation of the causes of decadal to centennial variations of the preindustrial atmospheric co2 concentration those causes are of potential significance for predicting future co2 levels and when attempting atmospheric verification of recent and future global carbon emission mitigation measures through coupled climate carbon cycle models

a mid pleistocene in situ fossil brown hyaena parahyaena brunnea latrine from gladysvale cave south africa abstract an in situ fossil latrine is reported from gladysvale cave south africa the latrine area is c 1 5 m in observable horizontal length and varies in height with a maximum of 20 cm indicating that deposition may have occurred over a considerable period of time the size of individual coprolites in the latrine varies with larger specimens 30 mm in diameter but the majority generally smaller c 15 20 mm the overall size and morphology of the coprolites and latrine are consistent with modern parahyaena brunnea which inhabit the caves today dated to between 195 and 257 ka the latrine indicates that troglodytic latrine making behaviour in p brunnea may be traced to at least the late middle pleistocene of southern africa