esr dating of the neanderthal site kebara cave israel abstract in 1985 a neanderthal skeleton was found in the cave of kebara in southern mt carmel electron spin resonance esr dates have been obtained on tooth enamel of gazelles found in layer x just overlying the layer in which the skeleton was found assuming early uptake of uranium by the teeth they yield an age of 60 6 ka assuming gradual linear uptake of uranium yields an age of 64 6 ka both age estimates are consistent with a previous estimate for the skeleton based on tl dating of burnt flint of 60 4 ka

el castillo cantabria northern iberia and the transitional aurignacian using radiocarbon dating to assess site taphonomy abstract the majority of archaeological remains found at el castillo in northern iberia were excavated between 1910 and 1914 by hugo obermaier since the 1980s el castillo has been studied through a detailed analysis of obermaier s original excavation notes the cleaning and study of the extant section and the excavation of material in the shelter entrance radiocarbon dating of charcoal from the modern 1980s onwards excavation suggested that unit 18 corresponding to aurignacian delta of the 1910s excavation was significantly earlier than other aurignacian assemblages in western europe combined with a reanalysis of the lithic and osseous industry these dates led to the suggestion that material in unit 18 and aurignacian delta was a transitional industry showing a gradual transformation of the mousterian into the upper palaeolithic the conclusion has profound implications for understanding the appearance of the upper palaeolithic in western europe however the theory has been heavily debated with criticism focusing on the analysis of the lithic and bone assemblage as well as the chronology we focus on the latter and assess whether the original dates were accurate whether they were well associated with the archaeology and whether there was vertical and lateral variation in the age of the assemblages within unit 18 and aurignacian delta new radiocarbon dates on humanly modified bone suggest that in the new area of excavation unit 18 is found to be earlier than 42 cal kbp with no evidence of material of a younger age in contrast in the old excavation area aurignacian delta does include material of a younger age this suggests that discussion of the transitional aurignacian can only include material from unit 18 in the new area of excavation

volcano hazards and potential risks on st paul island pribilof islands bering sea alaska abstract volcano hazards and potential risks on st paul island alaska are assessed on the basis of the recent volcanic history of the island the long term frequency of volcanic eruptions is estimated using a count of 40 identifiable vents considered to represent separate eruptions assuming regular temporal spacing of these events during the period 360 000 to 3230 y b p the estimated mean recurrence time is 0 11 10 3 eruption year and the eruptive interval is approximately 8900 years volcano hazards on st paul are associated exclusively with the eruption of low viscosity alkali basaltic magma the most important are lava flows tephra fallout and base surges other hazards include volcanic gases seismicity and ground deformation associated with dike intrusion beneath rift zones and explosive lava water interactions along coastal regions and water saturated ground the general characteristics of past volcanism on st paul indicate that the most likely styles of future eruptions will be 1 hawaiian style eruptions with fire fountains and pahoehoe lava flows issuing from one of two polygenetic shield volcanoes on the island 2 strombolian style scoria cone building eruptions with associated tephra fallout and eruption of short pahoehoe lava flows and 3 explosive surtseyan style phreatomagmatic eruptions initiating at some point along st paul s insular shelf given the relatively restricted range in volcanic phenomena on st paul the most significant question regarding volcano hazard and risk assessment is whether future eruptions will be confined to the same region on the island as the most recent activity if future activity follows the recent past resulting volcano hazards will most likely be located at inland areas sufficiently far from habitation that they will pose little threat to life or property an important caveat however is that st paul is constructed almost entirely from the products of volcanic eruptions with vents located all over the island thus a new vent could form at any place on the island including st paul s insular shelf and areas farther offshore because of the remote location of st paul in the storm lashed bering sea risks related to volcano hazards may be greater than they would be in a different setting where more stable meteorological conditions prevail and access by monitoring and relief groups is less challenging

historical ecology in beringia the south land bridge coast at st paul island a 14 m core of lake sediments from st paul island yields a long environmental history of the south coast of the bering land bridge tritium assay demonstrates that sands in the bottom 8 m of deposit are injected with modern water suggesting that a radiocarbon anomaly is the result of modern carbon introduced in groundwater the remaining radiocarbon chronology coupled with a time stratigraphic pollen zone boundary suggests that the record penetrates to the mid wisconsin interstadial pollen percentage data picea pollen influx and pollen species lists allow reconstruction of the land bridge vegetation which was tundra without shrubs or trees with bare ground and comparable to bering land bridge tundras found further north there was no coastal mild or wet strip plant associations comparable to those of the modern aleutians or pribilofs probably did not exist along the land bridge coast and the region was probably not suitable for breeding by fur seals and other marine mammals a cold dry continental air mass system reached to the coast itself the south land bridge coast did not offer an environment to aboriginal human populations that was significantly milder than that of the land bridge plains to the north at about 11 000 yr b p the wisconsin dry climate was replaced by a regimen comparable to that at the modern tree line of the interior and this climate in turn was replaced with the modern system at about 9500 yr b p climatic change was independent of fluctuating sea level

impact of climate and humans on the range dynamics of the woolly mammoth mammuthus primigenius in europe during mis 2 the woolly mammoth mammuthus primigenius was widespread in almost all of europe during the late pleistocene however its distribution changed because of population fluctuations and range expansions and reductions during marine oxygen isotope stage 2 mis 2 these processes were highly dynamic our analyses of 318 radiocarbon dates from 162 localities obtained directly from mammoth material confirmed important changes in mammoth range between 28 6 and 14 1 ka the greenland stadial 3 interval 27 5 23 3 ka was the time of maximum expansion of the mammoth in europe during mis 2 the continuous range was soon fragmented and reduced resulting in the disappearance of mammuthus during the last glacial maximum from 21 4 to 19 2 ka in all parts of the north european plain it is not clear whether mammoths survived in the east european plain the mammoth returned to europe soon after 19 0 ka and for the next 3 4 millennia played an important role in the lifeways of epigravettian societies in eastern europe mammoths became extinct in most of europe by 14 0 ka except for core areas such as the far northeast of europe where they survived until the beginning of the holocene no significant correlation was found between the distribution of the mammoth in europe and human activity

miocene adakitic intrusions in the zhongba terrane implications for the origin and geochemical variations of post collisional adakitic rocks in southern tibet abstract post collisional adakitic rocks 26 9 ma have been recognized in southern tibet for almost 20 years however their origins and geodynamics remain highly controversial this paper reports geochronological and geochemical data for the lasa intrusion exposed in the zhongba terrane and proposes implications for the origins of the miocene adakitic rocks in southern tibet the lasa intrusion consists of granite and granodiorite porphyries with zircon u pb ages of ca 16 ma the porphyries have high sio2 65 14 67 61 wt al2o3 15 13 16 10 wt k2o 2 87 3 54 wt and sr 727 1046 ppm contents and low y 9 13 ppm and yb 0 82 1 19 ppm contents they are enriched in light rare earth elements lrees and depleted in heavy rare earth elements hrees the porphyries display relatively low mgo contents 1 39 1 98 wt high sr y 65 98 and la yb n 18 8 25 5 ratios initial 87sr 86sr i ratios of 0 70912 0 70805 end t values of 6 4 to 7 9 206pb 204pb t ratios of 18 7108 18 7665 207pb 204pb t ratios of 15 6837 15 7118 and 208pb 204pb t ratios of 39 1600 39 3034 these signatures indicate that the lasa porphyries are adakitic rocks derived from the partial melting of a thickened lower crust the miocene adakitic rocks in the zhongba terrane have similar sr nd isotopic compositions to those of western lhasa and the himalaya terrane which differ from coetaneous adakitic rocks of the eastern lhasa terrane in terms of sr nd isotopic compositions based on the spatial distributions and isotopic features of the post collisional adakitic rocks in southern tibet we suggest that all of the adakitic rocks were derived from the partial melting of thickened lower crust and that their geochemical variations are mainly caused by the heterogeneity of lower crust

the aurignacian way of life contextualizing early modern human adaptation in the carpathian basin abstract the culture and dispersal of early modern humans are top priorities of many research agendas while the debate primarily centers on genetics dispersal trajectories and points of earliest presence the context climate landscape demography culture of the colonizing process is usually considered in a coarse grained manner or even ignored to understand the context of human dispersal and to decipher relevant push and pull factors requires the consideration of multiple environmental proxies and the research on different geographic scales in this paper we present the late quaternary carpathian basin as a specific context area of early modern human dispersal into europe the multitude of early upper paleolithic sites in this region suggests that it was part of a major dispersal corridor along the danube and its catchment area some 40 000 years ago the aurignacian land use model describes the interaction of early modern humans with their environment one important parameter is the specific distribution of archaeological sites that exemplifies their boundedness to specific eco zones to reconstruct the latter paleo environmental proxies and archaeological data are examined together in regional vector models and in a gis based landscape archaeology approach in the final section we present the carpathian basin as an idiosyncratic habitat that mirrors the dynamics and complexity of early modern human adaptation

identification of aniakchak alaska tephra in greenland ice core challenges the 1645 bc date for minoan eruption of santorini pearce nicholas westgate j a eastwood w j preece s j 2006 identification of aniakchak alaska tephra in greenland ice core challenges the 1645 bc date for minoan eruption of santorini geochemistry geophysics and geosystems 5 pp q03005 rae2008

a deglacial and holocene record of climate variability in south central alaska from stable oxygen isotopes and plant macrofossils in peat we used stable oxygen isotopes derived from bulk peat d 18 otom in conjunction with plant macrofossils and previously published carbon accumulation records in a w14 500 cal yr bp peat core ht fen from the kenai lowlands in south central alaska to reconstruct the climate history of the area we find that patterns are broadly consistent with those from lacustrine records across the region and agree with the interpretation that major shifts in d 18 otom values indicate changes in strength and position of the aleutian low al a semi permanent low pressure cell that delivers winter moisture to the region we find decreased strength or a more westerly position of the al relatively higher d 18 otom values during the bolling allerod holocene thermal maximum htm and late holocene which also correspond to warmer climate regimes these intervals coincide with greater peat preservation and enhanced carbon c accumulation rates at the ht fen and with peatland expansion across alaska the htm in particular may have experienced greater summer precipitation as a result of an enhanced pacific subtropical high a pattern consistent with modern d 18 o values for summer precipitation the combined warm summer temperatures and greater summer precipitation helped promote the observed rapid peat accumulation a strengthened al relatively lower d 18 otom values is most evident during the younger dryas neoglaciation and the little ice age consistent with lower peat preservation and c accumulation at the ht fen suggesting less precipitation reaches the leeward side of the kenai mountains during periods of enhanced al strength the peatlands on the kenai peninsula thrive when the al is weak and the contribution of summer precipitation is higher highlighting the importance of precipitation seasonality in promoting peat accumulation this study demonstrates that d 18 otom values in peat can be applied

evaluating the transitional mosaic frameworks of change from neanderthals to homo sapiens in eastern europe defining varying spatial and temporal analytical scales is essential before evaluating the responses of late neanderthals and early homo sapiens to abrupt environmental transitions aets and environmental disasters for the period 130 25 ka recent advances in addressing the population histories and interactions using both genetic and archaeological evidence of neanderthals and h sapiens have encouraged consideration of more subtle dynamics of archaeological change descriptions of change based on methodologies pioneered some 160 years ago are no longer adequate to explain the patterning we now see in the record new chronological results using multiple dating methods allow us to begin to unpick the spatial and temporal scales of change isochronic markers such as specific volcanic eruptions can be used to create temporal frameworks lattices and results from other dating techniques compared against them a combination of chronological lattices and direct dating of diagnostic artefacts and human fossils permits us for the first time to have greater confidence in connecting human recent hominin species and their behavioural responses to environmental conditions and in quantifying scales of change over time and space time transgression the timing of innovations particularly those in bone antler and ivory can be directly quantified and tested and used to re evaluate longstanding models of cultural change this paper also uses these new chronologies to explore the ecologies of late neanderthals and early h sapiens their population densities mobilities resources exploited and possible interactions environmental productivity estimates are used to generate new questions of potential population densities and mobilities and thus the sensitivity of these groups to environmental perturbations scales and intensities of effect on environments from natural disasters and aets notably heinrich events and the campanian ignimbrite eruption are defined as a scale from proximal to distal with local conditions topographic shelter or exposure serving to intensify or mitigate those effects

the reset project constructing a european tephra lattice for refined synchronisation of environmental and archaeological events during the last c 100 ka this paper introduces the aims and scope of the reset project response of humans to abrupt environmental transitions a programme of research funded by the natural environment research council uk between 2008 and 2013 it also provides the context and rationale for papers included in a special volume of quaternary science reviews that report some of the project s findings reset examined the chronological and correlation methods employed to establish causal links between the timing of abrupt environmental transitions aets on the one hand and of human dispersal and development on the other with a focus on the middle and upper palaeolithic periods the period of interest is the last glacial cycle and the early holocene c 100 8 ka during which time a number of pronounced aets occurred a long running topic of debate is the degree to which human history in europe and the mediterranean region during the palaeolithic was shaped by these aets but this has proved difficult to assess because of poor dating control in an attempt to move the science forward reset examined the potential that tephra isochrons and in particular non visible ash layers cryptotephras might offer for synchronising palaeo records with a greater degree of finesse new tephrostratigraphical data generated by the project augment previously established tephra frameworks for the region and underpin a more evolved tephra lattice that links palaeo records between greenland the european mainland sub marine sequences in the mediterranean and north africa the paper also outlines the significance of other contributions to this special volume collectively these illustrate how the lattice was constructed how it links with cognate tephra research in europe and elsewhere and how the evidence of tephra isochrons is beginning to challenge long held views about the impacts of environmental change on humans during the palaeolithic

revision of the cretaceous paleogene stratigraphic framework facies architecture and provenance of the xigaze forearc basin along the yarlung zangbo suture zone abstract new field investigation structural analysis review of biostratigraphy stratigraphic framework facies architecture provenance and flow direction of the cretaceous paleogene sedimentary strata in southern tibet resulted in reinterpretation of the evolution of the xigaze forearc basin xfb the xfb is comprised by flysch dominant xigaze group consisting of ngamring chongdoi and sangzugang formations and of the shallow marine cuojiangding group padana qubeiya quxia and gyalaze formations with their ages herein revised as the albian coniacian and the santonian ypresian respectively the deep sea flysch represented by the ngamring formation constitutes the early sedimentary fill of the xfb it was subdivided into five megasequences ms1 ms5 in order the early submarine fan facies stage channel submarine fan stage the mature submarine fan stage the highstand submarine fan stage and outer fan pelagic stage the paleocurrent flows were eastwards and westwards during the early and late stages of basin development and northwards and southwards during its middle stage indicating typical forearc basin sedimentation with longitudinal supply and lateral filling provenance studies point to multiple sources with andesitic debris sourced from the jurassic lower cretaceous yeba formation and sangri group formed in the volcanic island arc chains in the southern gangdese the four periods of the xfb development are 1 the formation of the xfb basement by the xigaze ophiolite and completed before the aptian the coeval deposits on the shelf are the sangzugang formation carbonate 2 the earliest xfb deposits of the earliest aptian age ca 125 120 ma represented by the chongdoi formation related to the residual forearc 3 composite forearc developed represented by the late albian late cenomanian flysch megasequences ms1 ms2 and the turonian coniacian flysch megasequences ms3 ms5 respectively and 4 the final stage of the xfb development started the terminal forearc stage represented by the late late cretaceous early paleogene shallow marine cuojiangding group and terminated during middle ypresian when the gyalaze formation was deposited

using palaeoenvironmental dna to reconstruct past environments progress and prospects palaeoenvironmental dna palendna is defined as ancient dna adna originating from disseminated genetic material within palaeoenvironmental samples sources of palendna include marine and lake sediments peat loess till ice permafrost palaeosols coprolites preserved gut contents dental calculus tephras and soils as well as deposits in caves rockshelters and at archaeological sites palendna analysis provides a relatively new tool for quaternary and archaeological sciences and its applications have included palaeoenvironmental and palaeodietary reconstructions testing hypotheses regarding megafaunal extinctions human environment interactions taxonomic studies and studies of dna damage because palendna samples comprise markedly different materials and represent wide ranging depositional and taphonomic contexts various issues must be addressed to achieve robust reproducible findings such issues include climatic and temporal limitations the biological origin and state free versus bound of palendna stratigraphic reliability sterile sampling ability to distinguish modern from adna signals dna damage and pcr amplification dna extraction methods and taxonomic resolution in this review we provide a non specialist introduction to the use of palendna for quaternary and archaeological researchers assess attributes and limitations of this palaeoenvir onmental tool and discuss future prospects of using palendna to reconstruct past environments copyright 2014 the authors journal of quaternary science published by john wiley sons ltd on behalf of quaternary research association

improved age estimates for key late quaternary european tephra horizons in the reset lattice abstract the research project response of humans to abrupt environmental transitions reset used tephra layers to tie together and synchronise the chronologies of stratigraphic records at archaeological and environmental sites with the increasing importance of tephra as chronological markers in sedimentary sequences both in this project and more generally comes a requirement to have good estimates for the absolute age of these volcanic horizons this paper summarises the chronology of the key tephra in the reset tephra lattice in the time range 10 60 ka bp from the existing literature from papers produced as part of the reset project and reanalysis conducted for this paper the paper outlines the chronological approach taken to the dating of tephra within the reset project and the basis for further work as part of the intimate integrating ice core marine and terrestrial records initiative for each of the tephra layers in the lattice the existing literature is discussed and where relevant date estimates updated using the latest radiocarbon calibration curves intcal13 and marine13 and methods maps show the approximate extent of tephra finds giving a visual indication of the coverage of the lattice in different time periods

magura cave bulgaria a multidisciplinary study of late pleistocene human palaeoenvironment in the balkans abstract two trenches excavated at magura cave north west bulgaria have provided late pleistocene lithic artefacts as well as environmental evidence in the form of large and small mammals herpetofauna and pollen recovered from crocuta coprolites one of the trenches also has a visible tephra layer which has been confirmed as representing the major campanian ignimbrite eruption and is accurately dated at the source area to 39 280 55 yrs and radiocarbon determinations have added to chronological resolution at the site the palaeoenvironment of the region during the late pleistocene is discussed in the context of hominin presence and shows a mosaic landscape in a region considered a crucial refugium for both plants and mammals including hominins

ecosystem impact of the campanian ignimbrite eruption in late pleistocene europe the dating of the campanian ignimbrite ci eruption to 37 000 cal yr b p draws attention to the coincidence of this volcanic catastrophe and the suite of coeval late pleistocene biocultural changes that occurred within and outside the mediterranean region these included the middle to upper paleolithic cultural transition and the supposed change from neanderthal to modern homo sapiens anatomy a subject of sustained debate no less than 150 km3 of magma were extruded in the ci eruption the signal of which can be detected in greenland ice cores as widespread discontinuities in archaeological sequences are observed at or following the ci event a significant interference with ongoing human processes in mediterranean europe is hypothesized

influence of bering strait flow and north atlantic circulation on glacial sea level changes sea level fluctuations of about 20 30m occurred throughout the last glacial period these fluctuations seem to have been derived primarily from changes in the volume of northern hemisphere ice sheets 1 3 and cannot be attributed solely to ice melt caused by varying solar radiation 4 here we use a fully coupled climate model to show that the transport of relatively fresh pacific water into the north atlantic ocean was limited when lower sea level restricted or closed the bering strait resulting in saltier north atlantic surface waters this invigorated deep convection in the north atlantic ocean strengthening meridional overturning circulation and northward heat transport in our model which consequently promoted melting of ice sheets in north america and europe our simulations show that the associated sea level rise led to a reopening of the bering strait the flux of relatively fresh water into the north atlantic ocean muted meridional overturning circulation and led to cooling and ice sheet advance in the northern hemisphere we conclude that the repetition of this cycle could produce the sea level changes that have been observed throughout the last glacial cycle

volcanic ash layers illuminate the resilience of neanderthals and early modern humans to natural hazards marked changes in human dispersal and development during the middle to upper paleolithic transition have been attributed to massive volcanic eruption and or severe climatic deterioration we test this concept using records of volcanic ash layers of the campanian ignimbrite eruption dated to ca 40 000 y ago 40 ka b p the distribution of the campanian ignimbrite has been enhanced by the discovery of cryptotephra deposits volcanic ash layers that are not visible to the naked eye in archaeological cave sequences they enable us to synchronize archaeological and paleoclimatic records through the period of transition from neanderthal to the earliest anatomically modern human populations in europe our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on neanderthals or early modern humans in europe we infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters

patterns of faunal extinction and paleoclimatic change from mid holocene mammoth and polar bear remains pribilof islands alaska abstract qagnax cave a lava tube cave on st paul island in the pribilofs has recently produced a mid holocene vertebrate faunal assemblage including woolly mammoth polar bear caribou and arctic fox several dates on the mammoth remains converge on 5700 14c yr bp these dates 2300 yr younger than mammoth dates previously published from the pribilof islands make these the youngest remains of proboscideans and of non extinct quaternary megafauna recovered from north america persistence of mammoths on the pribilofs is most parsimoniously explained by the isolation of the pribilofs and the lack of human presence in pre russian contact times but an additional factor may have been the local existence of high quality forage in the form of grasses enriched by nutrients derived from local holocene tephras this interpretation is reinforced by stable carbon and nitrogen isotope values obtained from the mammoth remains the endpoint of mammoth survival in the pribilofs is unknown but maybe coterminous with the arrival of polar bears whose remains in the cave date to the neoglacial cold period of 4500 to 3500 14c yr bp the polar bear record corroborates a widespread cooling of the bering sea region at that time

collection of radiocarbon dates on the mammoths mammuthus primigenius and other genera of wrangel island northeast siberia russia we present and discuss a full list of radiocarbon dates for woolly mammoth and other species of the mammoth fauna available from wrangel island northeast siberia russia most of the radiocarbon dates are published here for the first time of the124 radiocarbon dates on mammoth bone 106 fall between 3700 and 9000 yr ago we believe these dates bracket the period of mammoth isolation on wrangel island and their ultimate extinction which we attribute to natural causes the absence of dates between 9 12 ka probably indicates a period when mammoths were absent from wrangel island long bone dimensions of holocene mammoths from wrangel island indicate that these animals were comparable in size to those on the mainland although they were not large animals neither can they be classified as dwarfs occurrence of mammoth holocene refugia on the mainland is suggested based on other species of the mammoth fauna that have also been radiocarbon on wrangel island including horse bison musk ox and woolly rhinoceros it appears that the mammoth was the only species of that fauna that inhabited wrangel island in the mid holocene

last glacial vegetation of northern eurasia in order to investigate the potential role of vegetation changes in megafaunal extinctions during the later part of the last glacial stage and early holocene 42 10 ka bp the palaeovegetation of northern eurasia and alaska was simulated using the lpj guess dynamic vegetation model palaeoclimatic driving data were derived from simulations made for 22 time slices using the hadley centre unified model modelled annual net primary productivity anpp of a series of plant functional types pfts is mapped for selected time slices and summarised for major geographical regions for all time slices strong canonical correlations are demonstrated between model outputs and pollen data compiled for the same period and region simulated anpp values especially for tree pfts and for a mesophilous herb pft provide evidence of the structure and productivity of last glacial vegetation the mesophilous herb pft anpp is higher in many areas during the glacial than at present or during the early holocene glacial stage vegetation whilst open and largely treeless in much of europe thus had a higher capacity to support large vertebrate herbivore populations than did early holocene vegetation a marked and rapid decrease in anpp of mesophilous herbs began shortly after the last glacial maximum especially in western eurasia this is likely implicated in extinction of several large herbivorous mammals during the latter part of the glacial stage and the transition to the holocene

ams radiocarbon dating of middle and upper palaeolithic bone in the british isles improved reliability using ultrafiltration recent research at the oxford radiocarbon accelerator unit orau has shown that ultrafiltration of gelatin from archaeological bone can in many instances remove low molecular weight contaminants these can sometimes be of a different radiocarbon age and unless removed may severely influence results particularly when dating bones greater than two to three half lives of 14c in this study this methodology is applied to samples of late middle and early upper palaeolithic age from the british isles in many instances the results of redating invite serious reconsideration of the chronology for these periods copyright 2006 john wiley sons ltd

h4 abrupt event and late neanderthal presence in iberia heinrich event 4 h4 is well documented in the north atlantic ocean and the adjacent continents as a cooling event 39 000 yr before present bp to quantify the impact of this event with respect to climate and vegetation over the iberian peninsula we perform numerical experiments using a high resolution general circulation model forced by sea surface temperatures before and during h4 our model simulates an expansion of aridity over the peninsula during h4 a desertification of the south and a replacement of arboreal by herbaceous plants in the north all of which are in agreement with contemporaneous pollen sequences from marine cores located off the iberian peninsula our simulations demonstrate that the h4 marine event imprinted drastic changes over southern iberia which would not have favoured its occupation by anatomically modern humans therefore providing a plausible explanation for the delayed extinction of neanderthals in this region inferred from the archaeological record

timing and causes of mid holocene mammoth extinction on st paul island alaska relict woolly mammoth mammuthus primigenius populations survived on several small beringian islands for thousands of years after mainland populations went extinct here we present multiproxy paleoenvironmental records to investigate the timing causes and consequences of mammoth disappearance from st paul island alaska five independent indicators of extinction show that mammoths survived on st paul until 5 600 100 y ago vegetation composition remained stable during the extinction window and there is no evidence of human presence on the island before 1787 ce suggesting that these factors were not extinction drivers instead the extinction coincided with declining freshwater resources and drier climates between 7 850 and 5 600 y ago as inferred from sedimentary magnetic susceptibility oxygen isotopes and diatom and cladoceran assemblages in a sediment core from a freshwater lake on the island and stable nitrogen isotopes from mammoth remains contrary to other extinction models for the st paul mammoth population this evidence indicates that this mammoth population died out because of the synergistic effects of shrinking island area and freshwater scarcity caused by rising sea levels and regional climate change degradation of water quality by intensified mammoth activity around the lake likely exacerbated the situation the st paul mammoth demise is now one of the best dated prehistoric extinctions highlighting freshwater limitation as an overlooked extinction driver and underscoring the vulnerability of small island populations to environmental change even in the absence of human influence

tephra correlations and climatic events between the mis6 5 transition and the beginning of mis3 in theopetra cave central greece abstract three cryptotephra layers associated with important periods of climatic change were identified in the middle palaeolithic sequence of theopetra cave greece the lower cryptotephra layer thp tii5 is correlated with the p 11 pantellerian eruption dated to 128 131 ka this cryptotephra postdates a thick sequence of combustion layers that show a complex vegetation succession quite similar to that of the last deglaciation succession in the cave two other cryptotephras thp tii10 and thp tii12 are correlated with the nisyros upper pumice and the pantellerian y6 green tuff dated to 50 ka and 45 7 ka respectively this sequence confirms the position of the nisyros upper tephra below the pantellerian green tuff in the volcanic event stratigraphy of the mediterranean moreover these two upper cryptotephras bracket an extended combustion layer with interstadial vegetation characteristics that may be coincident with the complex greenland interstadial 13 14 on the basis of this new chronology it can be deduced that the intensity of occupation and presence or absence of humans in the cave were closely related to climatic changes in addition a remarkable similarity in the pattern of occupational intensity during the last two deglaciations can be suggested

spores of coprophilous fungi from under the dawson tephra 25 300 14c years bp yukon territory northwestern canada based on the analysis of pollen and macrofossils zazula et al zazula g d froesne d g elias s a kuzmina s la farge c reyes a v sanborn p t schweger c e smith c a s mathewes r w 2006 vegetation buried under dawson tephra 25 300 14c yr bp and locally diverse late pleistocene paleoenvironments of goldbottom creek yukon canada palaeogeography palaeoclimatology palaeoecology 242 253 286 reported an in situ riparian grassy meadow ecosystem and regional well drained steppe tundra buried by dawson tephra ca 25 300 bp at goldbottom creek in the canadian yukon territory an additional study of fungal spores in pollen slides from that site was completed ascospores of the coprophilous sordaria type sporormiella type and podospora type appeared to be of common occurrence pointing to the former presence of herbivores the analysis of the various spore types of coprophilous fungi in pollen slides is useful and may lead to further knowledge of the role of different herbivore taxa in past ecosystems 2007 elsevier b v all rights reserved

estimates of upper palaeolithic meta population size in europe from archaeological data abstract three databases 2961 georeferenced archeological sites simulated climatic variables simulating a typical warm phase of the isotopic stage 3 ios3 project and ethnographic of hunter gatherers hg were used to estimate the size growth rate and kinetics of the metapopulation of hg during four periods of the upper paleolithic in europe the size of the metapopulation was obtained by multiplying a demographic density per 100 km 2 by the size of the population territory of hg demographic density for each period was calculated by successively backprojecting a reference density obtained for the late glacial with inter period growth rate of the archeological sites from the aurignacian to the glacial maximum the metapopulation remained in a positive quasi stationary state with about 4400 5900 inhabitants 95 confidence interval ci95 1700 37 700 inhabitants during the glacial maximum the metapopulation responded to the cold i by moving the northern limits of its maximum expansion zone towards the low latitudes by 150 500 km from west to east ii by concentrating in few refuge zones mainly perigord cantabria and the iberian coasts iii by becoming perhaps distributed in smaller groups than during the pre and post glacial maximum the metapopulation reached 28 800 inhabitants ci95 11 300 72 600 during the mid late glacial recolonisation

paleoclimate modeling and paleoenvironmental interpretations for three instances of island dwelling mammoths abstract island dwelling mammoths are rare known from just three geographic locations wrangel island arctic ocean siberia the pribolof islands bering sea alaska and the northern channel islands northeast pacific ocean california in each of these locations they appear to inhabit refugia formed by post pleistocene eustatic sea level rise mammoths existed without the presence of humans wrangel island and the pribolofs until extinction or until contemporary with human colonization santa rosa island using a paleoclimate model developed by the senior author rab the paleoenvironmental conditions of these islands are depicted analyzed and interpreted this provided paleoclimatic evidence for the environments of the latest pleistocene and mid to late holocene mammoth populations and their demise

an oxygen isotope record of holocene climate change in the south central brooks range alaska abstract understanding the ecological and socio economic impacts of climatic warming requires knowledge of associated changes in moisture balance reconstructions of holocene moisture balance variation offer indispensible baseline information against which recent changes can be evaluated we analyzed chara stem encrustations in the sediments of takahula lake located in the south central brooks range of alaska for oxygen and carbon isotope composition to infer climatic change over the past 8000 years to help constrain climatic interpretations of the sediment 18 o record we also analyzed water samples from takahula and other lakes in the region for oxygen and hydrogen isotope composition results show that winter precipitation dominates the water balance of these lakes and that post input evaporation is a key control of lake water isotope composition of takahula lake stratigraphic patterns in chara 18 o supplemented by those in 13 c and sediment lithology reveal distinct changes in effective moisture precipitation minus evaporation over the past 8000 years effective moisture was relatively high from 8000 to 5000 cal bp with marked fluctuations between 6800 and 5000 cal bp it then decreased to reach a minimum around 4000 cal bp and increased with fluctuations from 4000 to 2500 cal bp followed by a decreasing trend toward the present that was interrupted by a wet little ice age centered at 400 cal bp aridity during the 20th century was among the highest of the entire 8000 year record at the millennial timescale the temporal patterns of moisture balance shifts at takahula lake are broadly coherent with those inferred from previous paleoclimate records from the region the chara 18 o values around 5600 cal bp and during the little ice age are up to 5 lower than at present and 3 6 lower than that of the modern input water to the lake these exceptionally low values suggest that factors other than effective moisture must have contributed to the pronounced variations in the takahula lake 18 o record increased winter precipitation associated with a westerly aleutian low position may account for 1 of the 18 o decrease other factors leading to the 18 o depletion during these periods probably include decreased temperatures as well as increased lake ice cover and associated reductions in evaporation

holocene climate variability although the dramatic climate disruptions of the last glacial period have received considerable attention relatively little has been directed toward climate variability in the holocene 11 500 cal yr b p to the present examination of similar to50 globally distributed paleoclimate records reveals as many as six periods of significant rapid climate change during the time periods 9000 8000 6000 5000 4200 3800 3500 2500 1200 1000 and 600 150 cal yr b p most of the climate change events in these globally distributed records are characterized by polar cooling tropical aridity and major atmospheric circulation changes although in the most recent interval 600 150 cal yr b p polar cooling was accompanied by increased moisture in some parts of the tropics several intervals coincide with major disruptions of civilization illustrating the human significance of holocene climate variability c 2004 university of washington all rights reserved

collagen stable isotopes provide insights into the end of the mammoth steppe in the central east european plains during the epigravettian higher 15 n values in bone collagen of mammoth mammuthus primigenius compared with coeval large herbivores is a classic trait of the mammoth steppe an exception applies to the epigravettian site of mezhyrich ca 18 17 4 ka cal bp in the central east european plains where mammoth bones have 15 n values equivalent to or in a lower range than those of horse specimens equus sp we expanded our preliminary dataset to a larger sampling size of mammoth other large herbivores and carnivores from contemporaneous and nearby sites of buzhanka 2 eliseevichi and yudinovo the unusual low mammoth 15 n values were confirmed at buzhanka 2 and for some specimens from eliseevichi while most individuals from yudinovo displayed the expected high 15 n values meaning similar to those of the large canids the possibility of a contrast in migration pattern is not supported since the 34 s values a marker of mobility do not correlate with the 15 n values of mammoth bone collagen no clear chronological tendency could be revealed at least not at the scale of radiocarbon dating the low range in 15 n values is likely to reflect a change in the specific niche of the mammoth in the southern part of its distribution

archaeozoological data from the mousterian level from moula guercy ardeche france bearing cannibalised neanderthal remains abstract the moula guercy cave in the southeast of france contains an important stratigraphic sequence attributed to the mousterian of middle and upper pleistocene age the faunal assemblages are rich and have been biostratigraphically well dated after methodical excavations from 1992 to 1999 layer xv representing a temperate optimum mis 5 5 yielded over a hundred neanderthal remains with evidence of cannibalism on six specimens this paper presents the detailed and hitherto unpublished results of the archaeozoological study of the large mammals from this level in 1999 relatively classical analytical methods were applied in order to compare the results with those of the cannibalised human remains studied separately the fauna from layer xv is not abundant but is very diversified represented by over 1500 remains from 23 different species the red deer is the second most consumed species after the human species layer xv appears to correspond to a summer or autumn hunting halt

late mesozoic tectonic evolution and growth of the tibetan plateau prior to the indo asian collision abstract the elevation of the tibetan plateau is a revolutionary event in the earth history which resulted in change not only of cenozoic regional and global climate but also of monsoon intensity a critical aspect for the development of the tibetan plateau that remains open to intense debate is whether the collision among the tibetan continental blocks or the subduction of the tethys prior to the indo asian collision in the cenozoic contributed to the plateau growth we propose here that an andean type orogen could have been present in southern tibet from the jurassic to early cretaceous but collapsed during the middle cretaceous based on a synthesis of existing structural sedimentary geochronological and geochemical data the orogeny is marked by north verging jurassic early cretaceous thrusting in the lhasa block a result of flat subduction of the yarlung zangpo neo tethys that is recorded by a narrow belt of 205 174 ma adakitic rocks along the southernmost margin of the lhasa block denudation of the orogen produced a thick up to 15 km sequence of jurassic turbidites and molasse type sediments on the northern lhasa block widespread middle cretaceous 135 100 ma postorogenic strongly peraluminous to calc alkaline magmatism and extensional deformation in the lhasa block and an extensive marine transgression in tibet indicate that the orogen broke down due to extension resulting from lithosphere delamination and asthenosphere upwelling meanwhile the north dipping subduction of the bangong meso tethys produced a wide jurassic middle cretaceous magmatic arc along the southern margin of the qiangtang block findings of 132 108 ma aged ophiolites rich with middle cretaceous radiolarians in central tibet indicate that the bangong meso tethys did not close until the late cretaceous repeated flat slab subduction of the yarlung zangpo neo tethys occurred during the late cretaceous 90 78 ma as indicated by the adakites in the southernmost lhasa block which together with the ongoing qiangtang lhasa collision could have contributed to the growth of the tibetan plateau

upb geochronology of gangdese transhimalaya plutonism in the lhasa xigaze region tibet abstract a series of different plutons from the lhasa xigaze segment of the gangdese transhimalaya belt has been studied by high resolution u pb analyses of zircon using zircon fractions of 5 100 grains each selected upon specific grain characteristics for two diorites located east of xigaze dazhuka the zircons yield concordant ages of 93 4 1 0 and 94 2 1 0 m y respectively also concordant ages of 41 1 0 4 and 41 7 0 4 m y have been obtained for two granodiorites collected southwest of lhasa qushui the precision on the ages of two granites from the xigaze and lhasa area is limited by two factors the presence of inherited radiogenic lead and the occurrence of subsequent lead loss however some concordant zircons detected in both granites define approximate ages of about 67 and 53 m y respectively the inherited lead components show that melting of precambrian material was involved in magma genesis the u pb ages substantiate a magmatic activity lasting from mid cretceous cenomanian to eocene lutetian time such a period of plutonism at the southern margin of eurasia as well as the occurrence of magma generation from continental crust suggest that the gangdese range results from the subduction of tethys oceanic lithosphere indian plate underneath eurasia eurasian plate if this model is true the collision of india with eurasia along the lhasa xigaze sector postdates the emplacement of the 41 m y old gangdese granodiorites i e the collision occurred after lutetian time

old crow tephra across eastern beringia a single cataclysmic eruption at the close of marine isotope stage 6 abstract old crow tephra is the largest and most widespread quaternary eruption presently known in eastern beringia its major and trace element geochemistry fe ti oxides and stratigraphic and paleoecological context indicate that it is the result of a single cataclysmic eruption the proximal region may well have experienced tephra fallout from small eruptions just prior to or after the old crow event but there is no evidence to indicate that the distal area was affected we recalculate the glass fission track age at 124 10 ka which coupled with stratigraphic and paleoenvironmental reconstructions indicates that deposition occurred prior to development of the last interglacial boreal forest which suggests a latest marine isotope stage mis 6 age the bulk tephra volume erupted is estimated by three different approaches that are in broad agreement at 200 km 3 but this result must be considered as tentative given the poor controls on definition of isopachs over such a large area the source caldera although presently unrecognized is located in the eastern aleutian arc possibly at or near the emmons lake volcanic center

implications of shortening in the himalayan fold thrust belt for uplift of the tibetan plateau 1 recent research in the himalayan fold thrust belt provides two new sets of observations that are crucial to understanding the evolution of the himalayan tibetan orogenic system first u pb zircon ages and sm nd isotopic studies demonstrate that 1 greater himalayan medium to high grade metasedimentary rocks are much younger than true indian cratonic basement and 2 these rocks were tectonically mobilized and consolidated with the northern margin of gondwana during early paleozoic orogenic activity these observations require that greater himalayan rocks be treated as supracrustal material in restorations of the himalayan fold thrust belt rather than as indian cratonic basement in turn this implies the existence of greater himalayan lower crust that is not exposed anywhere in the fold thrust belt second a regional compilation of shortening estimates along the himalayan arc from pakistan to sikkim reveals that 1 total minimum shortening in the fold thrust belt is up to 670 km 2 total shortening is greatest in western nepal and northern india near the apex of the himalayan salient and 3 the amount of himalayan shortening is equal to the present width of the tibetan plateau measured in an arc normal direction north of the indus yalu suture zone this information suggests that a slab of greater indian lower crust composed of both indian cratonic lower crust and greater himalayan lower crust with a north south length of 700 km may have been inserted beneath the tibetan crust during the cenozoic orogeny we present a modified version of the crustal underthrusting model for himalayan tibetan orogenesis that integrates surface geological data recent results of mantle tomographic studies and broadband seismic studies of the crust and upper mantle beneath the tibetan plateau previous studies have shown that incremental mesozoic and early cenozoic shortening had probably thickened tibetan crust to 45 55 km before the onset of the main cenozoic orogenic event thus the insertion of a slab of greater indian lower crust with maximum thickness of 20 km tapering northward could explain the cenozoic uplift of the tibetan plateau the need for tibetan crust to stretch laterally as the greater indian lower crust was inserted may explain the widespread east west extension in the southern half of the plateau our reconstruction of the himalayan fold thrust belt suggests that indian cratonic lower crust of presumed mafic composition and high strength should extend approximately halfway across the tibetan plateau to the banggong suture from there northward we predict that the tibetan plateau is underlain by more felsic and therefore weaker lower crust of greater himalayan affinity two slab break off events are predicted by the model the first involved neotethyan oceanic lithosphere that foundered 45 35 ma and the second consisted of greater indian lithosphere most likely composed of greater himalayan material that delaminated and foundered 20 10 ma asthenospheric upwelling associated with the break off events may explain patterns of cenozoic volcanism on the tibetan plateau although the model predicts a northward migrating topographic front due solely to insertion of greater indian lower crust the actual uplift history of the plateau was complicated by early middle tertiary shortening of tibetan crust

neandertal and denisovan dna from pleistocene sediments although a rich record of pleistocene human associated archaeological assemblages exists the scarcity of hominin fossils often impedes the understanding of which hominins occupied a site using targeted enrichment of mitochondrial dna we show that cave sediments represent a rich source of ancient mammalian dna that often includes traces of hominin dna even at sites and in layers where no hominin remains have been discovered by automation assisted screening of numerous sediment samples we detected neandertal dna in eight archaeological layers from four caves in eurasia in denisova cave we retrieved denisovan dna in a middle pleistocene layer near the bottom of the stratigraphy our work opens the possibility of detecting the presence of hominin groups at sites and in areas where no skeletal remains are found

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

a new and less destructive laboratory procedure for the physical separation of distal glass tephra shards from sediments abstract tephrochronology a key tool in the correlation of quaternary sequences relies on the extraction of tephra shards from sediments for visual identification and high precision geochemical comparison a prerequisite for the reliable correlation of tephra layers is that the geochemical composition of glass shards remains unaltered by natural processes e g chemical exchange in the sedimentary environment and or by laboratory analytical procedures however natural glasses particularly when in the form of small shards with a high surface to volume ratio are prone to chemical alteration in both acidic and basic environments current techniques for the extraction of distal tephra from sediments involve the cleaning of samples in precisely such environments and at elevated temperatures the acid phase of the cleaning process risks alteration of the geochemical signature of the shards while the basic phase leads to considerable sample loss through dissolution of the silica network here we illustrate the degree of alteration and loss to which distal tephras may be prone and introduce a less destructive procedure for their extraction this method is based on stepped heavy liquid flotation and which results in samples of sufficient quality for analysis while preserving their geochemical integrity in trials this method out performed chemical extraction procedures in terms of the number of shards recovered and has resulted in the detection of new tephra layers with low shard concentrations the implications of this study are highly significant because i the current database of distal tephra records and their corresponding geochemical signatures may require refinement and ii the record of distal tephras may be incomplete due to sample loss induced by corrosive laboratory procedures it is therefore vital that less corrosive laboratory procedures are developed to make the detection and classification of distal glass tephra more secure

the middle and upper palaeolithic at la crouzade cave gruissan aude france new excavations and a chronostratigraphic framework abstract this paper presents new archaeological material and first dates on upper pleistocene layers at the site of la crouzade cave gruissan aude france the site was first excavated by t and p helena at the beginning of the twentieth century and the excavations were recently completed during three years 2016 2018 of systematic campaigns we obtained dates from middle palaeolithic layers using two methods ams 14c dates were obtained from bone and charcoal and combined esr u series dating was undertaken on horse teeth together these methods allowed us to date this mousterian sequence to 49 776 44805 cal bp for the deepest level layer c8 and from 42 000 3000 years bp for the top layer c6 the upper palaeolithic layers are preserved only as patches in the actual excavation area but a date was obtained from a piece of charcoal collected from a small hearth preserved in the first layer c5 above middle palaeolithic deposits which indicates an age similar to that of a modern human maxillary previously analysed and re dated here from 36 014 to 34402 cal bp confirming its stratigraphic attribution the middle palaeolithic lithics at the site were first described as para charentian cultural facies following typological analyses the revision of the earlier collection supplemented with the new material using a technological approach allow to identify two layers dominated by levallois production followed by discoid production layers c8 and c6 surrounding an original assemblage layer c7 characterised by a dominant levallois production completed by three secondary production systems of equal importance including discoid ssda and a quina like production the faunal spectrum predominantly comprises an assemblage of pleistocene large mammals and biochronological studies corroborate the dates obtained

carbon and nitrogen stable isotope analysis of northwest european horse bone and tooth collagen 40 000 bp present palaeoclimatic interpretations abstract carbon and nitrogen stable isotope ratios of bone and tooth dentine collagen from 142 horses were analysed to consider the potential of isotopic analysis of faunal remains as a palaeoenvironmental and palaeoclimatic proxy a general trend through time towards lighter 13 c values was observed but with an obvious depletion at the late glacial holocene transition horse 13 c values appear to track plant 13 c although phenomenon such as the canopy effect may influence faunal 13 c values we believe that the influence on plants of increasing atmospheric co 2 is the primary factor in the change in faunal 13 c values at the late glacial holocene transition a post glacial depletion in horse 15 n values is observed in areas proximal to glacial retreat although no data is available in these areas during the last glacial maximum horse 15 n values are presumed to reflect plant 15 n values depleted plant nitrogen may be attributed to a number of factors e g water availability temperature cycling of nitrogen in the soil soil nutrient availability especially phosphorus in the post glacial period and the type of mycorrhizal associations formed with plant these effects may be interrelated and be linked such that a positive feedback can give a non linear response to a single parameter

nyainqentanglha shear zone a late miocene extensional detachment in the southern tibetan plateau a major low angle ductile shear zone containing s c mylonites involves metamorphosed granitic rocks at the southeastern edge of the nyainqentanglha mountain range southern tibet prominent triangular facet geomorphology is developed by valley erosion of the detachment surface defined by the top of the southeast dipping mylonitec shear zone kinematic criteria consistently indicate a top to southeast sense of shear the ductile shearing deformation is inferred from isotopic cooling ages to have occurred during the interval 11 5 ma late miocene we interpret the shear zone as a regional extensional detachment its development indicates when the extensional tectonics in this area started which in turn may mark the time when the maximum sustainable surface elevation and perhaps crustal thickness was reached in southern tibet

new chronological constraints for middle palaeolithic mis 6 5 3 cave sequences in eastern transylvania romania abstract the middle to upper palaeolithic transition is one of the crucial periods of change in the prehistory of europe due to the full emergence continent wide of modern human lithic technologies and detrimental of neanderthal survival knowledge about the transition is growing however the evidence for cultural and technological developments for the middle palaeolithic in the carpathian lower danube basin is still rather sparse here we discuss latest findings arising from a chronological investigation of middle palaeolithic assemblages within the varghis karst eastern transylvania romania combining our first chronological results with information from previous excavations we can distinguish two main stages of habitation albeit middle palaeolithic lithics and faunal remains appear scattered throughout the investigated profile within the abri 122 rock shelter in order to augment the typological cultural considerations we applied direct radiocarbon dating on bones and charcoal from within the occupation layers radiocarbon dating of bones suggests that the middle palaeolithic sequence is older than the upper dating limit of the method whereas direct luminescence ages on the lowermost productive horizon and immediately above it indicate surprisingly old ages of ca 106 141 ka osl optically stimulated or 99 174 ka irsl infrared stimulated multiple protocol dating of charcoal found within the two habitation layers produced ages 38 14 c ka bp also suggesting that the lowermost lithic rich horizon pertains to the middle palaeolithic industries overall the recovered lithics currently forming one of the most significant collections for romania are fully consistent with two main habitation phases connected to middle palaeolithic cultural affinities the occurrence of a volcanic ash layer within ursului cave and originating from the ciomadul volcanic complex carpathians is first reported here recently dated to 43 50 ka it might represent an important marker horizon providing that it is identified within other palaeolithic cave assemblages