ecoregions and stream morphology in eastern oklahoma abstract broad scale variables i e geology topography climate land use vegetation and soils influence channel morphology how and to what extent the longitudinal pattern of channel morphology is influenced by broad scale variables is important to fluvial geomorphologists and stream ecologists in the last couple of decades there has been an increase in the amount of interdisciplinary research between fluvial geomorphologists and stream ecologists in a historical context fluvial geomorphologists are more apt to use physiographic regions to distinguish broad scale variables while stream ecologists are more apt to use the concept of an ecosystem to address the broad scale variables that influence stream habitat for this reason we designed a study using ecoregions which uses physical and biological variables to understand how landscapes influence channel processes ecoregions are delineated by similarities in geology climate soils land use and potential natural vegetation in the fluvial system stream form and function are dictated by processes observed throughout the fluvial hierarchy recognizing that stream form and function should differ by ecoregion a study was designed to evaluate how the characteristics of stream channels differed longitudinally among three ecoregions in eastern oklahoma usa boston mountains ozark highlands and ouachita mountains channel morphology of 149 stream reaches was surveyed in 1st through 4th order streams and effects of drainage area and ecoregion on channel morphology was evaluated using multiple regressions differences existed 0 05 among ecoregions for particle size bankfull width and width depth ratio no differences existed among ecoregions for gradient or sinuosity particle size was smallest in the ozark highlands and largest in the ouachita mountains bankfull width was larger in the ozark highlands than in the boston mountains and ouachita mountains in larger streams width depth ratios of the boston mountains and ozark highlands were not statistically different significant differences existed however between the boston mountains and ozark highlands when compared individually to the ouachita mountains we found that ecoregions afforded a good spatial structure that can help in understanding longitudinal trends in stream reach morphology surveyed at the reach scale the hierarchy of the fluvial system begins within a broad relatively homogenous setting that imparts control on processes that affect stream function ecoregions provide an adequate regional division to begin a large scale geomorphic study of processes in stream channels

hierarchical patterns of physical biological associations in river ecosystems abstract the interplay of biological and physical patterns and processes within river ecosystems generates a complex matrix of interactions a challenge in interdisciplinary river science is to dissect patterns and processes in multi causal river ecosystems into hierarchical levels of organization hierarchy theory and the associated concept of scale provides a sound framework for achieving this we present two interdisciplinary case studies that demonstrate how a multi scale approach can dissect hierarchies of organization in river ecosystems the first case study examined patterns of large wood character and distribution at three scales of a hierarchy of morphological river system organization in the large lowland river murray the character and distribution of large wood was uniform at the largest reach scale 95 km length of river because stream energy conditions are relatively uniform within the reach however there was an association between lower level functional sets straight or bend sections of river and functional units 12 quadrats within each functional set and the character and distribution of large wood because stream energy differs between straight and bend morphologies and the inner and outer channel functional units thus functional sets and functional units are important levels of organization for large wood in the river murray the second case study examined the associations between macroinvertebrate assemblage distribution and environmental influences across a hierarchy of river system organization in the upland murrumbidgee river catchment we previously demonstrated that macroinvertebrate assemblages were arranged hierarchically at the region cluster within region reach within cluster and riffle within reach scales with region and reach being the strongest signatures in this study we related different scaled environmental factors collected across a hierarchy of catchment zone valley confinement reach similar stream orders and riffle scales to the region and cluster levels of macroinvertebrate distribution the hierarchical pattern of large region level and local reach level macroinvertebrate distribution was matched by a large catchment scale and local reach scale of environmental influence intermediate zone scale environmental factors and smaller riffle scale factors were not important influences thus large regions and catchments and local reaches are important levels of organization for macroinvertebrate environment associations in rivers of the upper murrumbidgee catchment both case studies support the applicability of hierarchy theory to describe the organization of physical biological associations in river ecosystems the multi scaled approach allowed the detection of levels of hierarchical organization and showed other hierarchical characteristics such as emergent properties and top down constraint bottom up influence hierarchical understanding of river ecosystem organization will enhance river conservation and management because it facilitates a holistic ecosystem perspective rather than a partial single scale single component or single discipline perspective

transtensional model for the sierra nevada frontal fault system eastern california active strike slip and normal faults along the eastern margin of the sierra nevada primarily accommodate northwestward translation of the sierra nevada central valley i e sierran microplate with respect to stable north america strike slip faults bordering the eastern sierran microplate are subparallel to small circles about the sierra nevada north american euler pole normal faults of the sierra nevada frontal fault system strike 45 clockwise of the small circle trajectories and exhibit well defined left stepping en echelon patterns consistent with formation in dextral transcurrent regime major graben bordering the northeastern sierran microplate are located in regions where the locus of range front deformation steps abruptly eastward in a releasing geometry relative to sierra nevada north american motion crustal shortening occurs at the northern end of the sierran microplate where a component of northwest dextral shear steps westward in a left restraining geometry across the sierran crest to the sacramento valley kinematic inversions of earthquake focal mechanisms from the walker lane belt bordering the eastern sierra nevada indicate that seismogenic deformation primarily is characterized by horizontal shearing and oblique crustal thinning directions of macroscopic dextral shear inferred from the inversions are subparallel to the trajectories of small circles about the sierra nevada north american euler pole normal faulting along most of the eastern sierran range front thus appears to primarily accommodate microplate translation rather than sierran uplift or regional basin and range extension

input storage and distribution of large woody debris along a mountain river continuum the drome river france abstract large woody debris lwd input storage and distribution were studied along the drome river a french alpine river with an active shifting channel and a well developed riparian forest lwd input from the floodplain is low 669 6 mg year 1 between 1948 and 1971 and 569 3 mg year 1 between 1971 and 1991 based on estimates of average lwd mass per study plot a range of 766 2122 mg year 1 of lwd were stored within the active channel e g unvegetated bars and low flow channel 60 km course covering 492 ha lwd accumulations are mainly observed on gravel bars at a limited number of preferential sites they are relatively rare and are randomly distributed in the low flow channel consequently lwd location is mainly associated with the decrease of flow level in shallow sectors in the low flow channel lwd stop en route is primarily caused by in channel structures such as boulders or vegetated islets general geomorphological factors e g pattern slope etc provide less explanation of lwd distribution moreover the residence time of lwd accumulations on the drome river is short lwd storage 1 3 3 7 times the annual lwd input from the floodplain and their morphogenic role is negligible few of the accumulations are buried or characterized by vegetation shoots and associated pools

northwest basin and range tectonic deformation observed with the global positioning system 1999 2003 1 we use geodetic velocities obtained with the global positioning system gps to quantify tectonic deformation of the northwest basin and range province of the western united states the results are based on gps data collected in 1999 and 2003 across five new quasi linear networks in northern nevada northeast california and southeast oregon the velocities show 3 mm yr westward movement of northern nevada with respect to stable north america west of longitude 119 w the velocities increase and turn northwest parallel to sierra nevada great valley microplate motion and similar to velocities previously obtained to the south the observations are explained by a kinematic model with three domains that rotate around euler poles in eastern oregon and western idaho northeast california experiences internal dextral shear deformation 11 2 3 6 nstrain yr subparallel to pacific north america motion relative motions of the domains imply 2 5 mm yr approximately east west extension in northwest nevada and 1 4 mm yr approximately north south contraction near the california oregon border the northward decreasing approximately east west extension in northwest nevada is consistent with the northern termination of basin and range deformation faulting and characteristic topography no significant extension is detected in the oregon basin and range the oregon cascade arc moves north at 3 5 mm yr and is possibly influenced by the approximately eastward motion of the juan de fuca plate these results disagree with secular northwest trenchward motion of the oregon forearc inferred from paleomagnetic rotations south of latitude 43 however trenchward motion exists and is consistent with block rotations approximately east west basin and range extension and northwest sierra nevada translation

log jam effects on bed load mobility from experiments conducted in a small gravel bed forest ditch abstract bed load transport experiments have been conducted in a steep gravel bed open ditch this initially straight ditch has been neglected for many years and looks at present like a second order natural stream channel the channel flows through a spruce forest and several log jams have produced chutes and pools creating supplementary roughness the total shear stress has been evaluated using the slope hydraulic radius product and the ratio between grain and bed form shear stresses has been calculated using different methods the shear stress has also been evaluated from the shear velocities and this gives a good evaluation of the grain shear stress additional experiments have been conducted with marked pebbles to estimate particle mobility and to improve the motion equations equations such as c a di d50 b b defined by andrews apply in these cases but the values of a and b are lower than those produced by this author in a second stage of experimentation we have destroyed the log jams resulting in a diminution of the roughness and critical shear stress when the total shear stress is used an increase of the grain shear stress and thus greater bed particle mobility for the same discharge it emerges from these experiments that the log jams contribute to the reduction of bed load evacuation and explain the very weak bed load discharge measured by a bed load trap 0 3 t km 2 yr 1

geomorphology and ecosystems challenges and keys for success in bridging disciplines geomorphology plays a fundamental role in controlling many ecosystem processes and in turn ecosystems can have a profound influence on many geomorphic forms and processes over the past few decades a proliferation of research has developed at the interface of geomorphology and ecosystems ecology the 2005 binghamton symposium brought together some of the leading researchers from both communities to address these critical interfaces between the disciplines this paper reviews some of the aspects of the disciplines of geomorphology and ecosystems ecology and the papers presented at the symposium the papers in this volume illustrate the current status of the disciplines the difficulties in bridging the disciplines and the issues that are emerging as research priorities

acid sulfate alteration of fluorapatite basaltic glass and olivine by hydrothermal vapors and fluids implications for fumarolic activity and secondary phosphate phases in sulfate rich paso robles soil at gusev crater mars 1 phosphate rich rocks and a nearby phosphate rich soil paso robles were analyzed in gusev crater mars by the mars exploration rover spirit and interpreted to be highly altered possibly by hydrothermal or fumarolic alteration of primary phosphate rich material to test mineral phases resulting from such alteration we performed hydrothermal acid vapor and acid fluid experiments on olivine ol fluorapatite ap and basaltic glass gl as single phases and a mixture of phases minerals formed include ca al fe and mg sulfates with different hydration states anhydrite bassanite gypsum alunogen hexahydrite and pentahydrite phosphate bearing minerals formed included monocalcium phosphate monohydrate mcp acid vapor and acid fluid alteration of fluorapatite only and ferrian giniite acid fluid alteration of the ol gl ap mixture mcp is likely present in paso robles if primary ca phosphate minerals reacted with sulfuric acid with little transport of phosphate under fluid rock ratios allowing transport of phosphate a ferric phosphate phase such as ferrian giniite might form instead mossbauer measurements of ferrian giniite bearing alteration products and synthetic ferrian giniite are consistent with spirit s mossbauer measurements of the ferric bearing phase in paso robes soil but are also consistent with ferric sulfate phases in the low p soil arad samra therefore mossbauer data alone do not constrain the fluid rock ratio however the excess iron hematite in paso robles soil which implies aqueous transport combined with our laboratory experiments suggest acid sulfate alteration in a hydrothermal fumarolic environment at fluid rock ratios sufficient to allow dissolution transport and precipitation of secondary chemical components including a ferric phosphate such as ferrian giniite

radiocarbon and mammoth bones what s in a date the radiocarbon dating method has developed into a reliable dating method for organic sample materials the latest calibration curve released enables numerical dating covering the complete dating range of the method however the category of fossil bones is the subject of discussion concerning validity of the dates in particular for the oldest part of the c 14 timescale this is a complex interplay of sample material integrity contamination issues and proper blanks in practice a safe upper limit for c 14 dates of bone material appears to be 45 000 bp 50 000 calbp c 2014 elsevier ltd and inqua all rights reserved

thermoluminescence dating of flint abstract our ancestors have been making flint tools for over a million years the tools or the flakes left by the flint knappers have become important markers of prehistoric habitats the imperishable and ubiquitous nature of flint explains why generations of prehistorians have used it to build a stone age chronology to be dateable by tl flint must be heated to at least 450 c while human use of fire may be as old as half a million years the first true hearths appear late during the lower paleolithic period at terra amata one of the oldest hearths discovered in france was dated to 230 40 ka bp by wintle and aitken 1977 by the dawn of the middle paleolithic fire must have become fully domesticated judging by the accumulations of charred debris that henceforth litter human habitats for example at the middle paleolithic site of kebara the profusion of hearths is vividly illustrated by numerous superposed white ash and black charcoal layers extending to a depth of 4 m meignen et al 1989

laser ablation u series analysis of fossil bones and teeth abstract over the past decade we have applied laser ablation icp mass spectrometry u series analysis to a large number of bones and teeth the method is fast and provides high resolution data of u series isotopes which give insights into the complexity of uranium migration into within and out of bones in this paper we present our laser ablation approach in detail from the experimental set up to data reduction and uranium diffusion modelling laser ablation analysis can now be applied with minimum damage complete diffusion data sets can be obtained by laser drilling which leaves a hole of around 200 m in diameter and 1 2 mm depth if the natural u diffusion follows a simple single stage process valuable age information can be obtained in other cases highly complex u migrations have been observed which make any age assessment impossible two examples from wadjak and callao illustrate the potential of nearly non destructive laser ablation u series analysis of human skeletal tissues the results demonstrate the physical presence of modern humans in south east asia at a time when our species just started to migrate into europe

challenges in sample processing within radiocarbon dating and their impact in 14c dates as data studies abstract for decades researchers have employed sets of radiocarbon dates to reconstruct trends in ancient human populations the overarching assumption in this analysis is that the frequency of dates is proportional to the magnitude of past human activity thus the distribution of summed or otherwise summarized dates is used to extrapolate population density and mobility patterns there are however a number of underlying assumptions associated with this analysis that workers address to varying degrees and which if false and not critically accounted for will introduce bias misrepresent the magnitude of activity and ultimately prove misleading in archaeological interpretations in this regard research has so far mainly focused on correcting for the effects of time dependent degradation of archaeological sites and constituent materials calibration irregularities and the efficacy of the statistical methods used assumptions directly related to sample processing in radiocarbon dating however are less discussed in 14c dates as data analyses it is for example assumed that all carbonaceous materials will yield sufficient endogenous carbon for radiocarbon measurement yet sample failure in radiocarbon dating is common and contingent on largely deterministic factors such as post depositional environment sets of radiocarbon dates analyzed therefore represent successful measurements independent of reliability in this work we discuss the biases introduced by challenges in radiocarbon processing and their impact on 14c dates as data studies

floodplain river ecosystems lateral connections and the implications of human interference abstract floodplains are ecotones that form a transition between aquatic and terrestrial environments these important ecosystems can be described as dynamic spatial mosaics in which water plays an important role in connecting various patches on the floodplain surface hydrological connections facilitate the exchange of carbon and nutrients between the river channel and the floodplain and therefore influence the productivity of the entire river system this paper examines the influence of hydrological connections on the potential exchange of dissolved organic carbon between a large australian floodplain to a river channel and the effects of land and water developments on these exchanges the paper proposes that an understanding of floodplain ecosystems requires an interdisciplinary approach a recognition of the importance of the three disciplines hydrology geomorphology and ecology large scale water resources and floodplain development has significantly altered the spatial and temporal patterns of hydrological characteristics in the lower balonne floodplain australia the magnitude frequency and duration of flooding events have all been reduced the construction of levees and water storages has also reduced the reactive floodplain surface area the presented data show the impacts of these changes on the potential supply of dissolved organic carbon from the floodplain surface during periods of inundation annual reductions of up to 1293 tonnes of dissolved organic carbon supply were noted and reductions were especially significant for floods with an average recurrence interval of 2 years or less some small flood events no longer facilitate the potential supply of dissolved organic carbon from the floodplain to the river channel because of water resources and floodplain developments

quaternary science 2007 a 50 year retrospective this paper reviews 50 years of progress in understanding the recent history of the earth as contained within the stratigraphical record of the quaternary it describes some of the major technological and methodological advances that have occurred in quaternary geochronology examines the impressive range of palaeoenvironmental evidence that has been assembled from terrestrial marine and cryospheric archives assesses the progress that has been made towards an understanding of quaternary climatic variability discusses the development of numerical modelling as a basis for explaining and predicting climatic and environmental change and outlines the present status of the quaternary in relation to the geological time scale the review concludes with a consideration of the global quaternary community and the challenge for the future

bio geomorphology and resilience thinking common ground and challenges abstract geomorphology plays a fundamental role in shaping and maintaining landscapes as well as influencing the social and ecological systems that occupy and utilize these landscapes in turn social ecological systems can have a profound influence on geomorphic forms and processes these interactions highlight the tightly coupled nature of geomorphic systems over the past decade there has been a proliferation of research at the interface of geomorphology and resilience thinking and the 2017 binghamton symposium brought together leading researchers from both communities to address mutual concerns and challenges of these two disciplines this paper reviews some of the key intersections between the disciplines of bio geomorphology and resilience thinking and the papers presented at the symposium the papers in this volume illustrate the current status of the disciplines the difficulties in bridging the disciplines and the issues that are emerging as research priorities

gps derived strain in northwestern california termination of the san andreas fault system and convergence of the sierra nevada great valley block contribute to southern cascadia forearc contraction abstract gps derived velocities 1993 2002 in northwestern california show that processes other than subduction are in part accountable for observed upper plate contraction north of the mendocino triple junction mtj region after removing the component of elastic strain accumulation due to the cascadia subduction zone from the station velocities two additional processes account for accumulated strain in northern california the first is the westward convergence of the sierra nevada great valley sngv block toward the coast and the second is the north northwest impingement of the san andreas fault system from the south on the northern california coastal region in the vicinity of humboldt bay sierra nevada great valley block motion is northwest toward the coast convergent with the more northerly north northwest san andreas transform fault parallel motion in addition to the westward converging sierra nevada great valley block san andreas transform parallel shortening also occurs in the humboldt bay region approximately 22 mm yr of distributed pacific sngv motion is observed inland of cape mendocino across the northern projections of the maacama and bartlett springs fault zones but station velocities decrease rapidly north of cape mendocino the resultant 6 10 mm yr of san andreas fault parallel shortening occurs above the southern edge of the subducted gorda plate and at the latitude of humboldt bay part of the san andreas fault parallel shortening may be due to the viscous coupling of the southern edge of the gorda plate to overlying north american plate we conclude that significant portions of the upper plate contraction observed north of the mtj region are not solely a result of subduction of the gorda plate but also a consequence of impingement of the western edge of the sierra nevada great valley block and growth of the northernmost segments of the san andreas fault system

prediction of effects of woody debris removal on flow resistance a simple technique for predicting the darcy weisbach friction factor for river channels with varying amounts of large woody debris was developed first debris density is determined based on measurement or visual estimation of cross sectional areas of debris formations in the plane perpendicular to flow the darcy weisbach friction factor is then computed using debris density channel geometry mean flow velocity and the debris drag coefficient the debris drag coefficient may be computed fom a power function with experimentally determined coefficients for verification of the proposed procedure debris density and friction factors were measured in river reaches in western tennessee and southeastern new south wales australia friction factors computed using the procedure were within 30 of measured values for straight sand bed reaches and within 38 of measured values for sinuous gravel bed reaches the computational procedure explained 84 of the variance in observed values

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

thermoluminescence dating of le moustier dordogne france the chronology of the neanderthal cultures commonly called mousterian which flourished between 100 000 and 40 000 yr ago has not been well established the lower rock shelter of le moustier provides one of the most important stratigraphic sequences incorporating ten main mousterian layers originally identified by peyrony1 and two early upper palaeolithic layers the stratigraphy of which is mainly defined in terms of the regional climatic chronostratigraphy derived from the alpine glacial sequence1 4 a correlation has recently been proposed between the chronostratigraphy of dordogne and the past 125 000 yr of the well established stratigraphy based on oceanic oxygen isotope ratios5 6 but the lack of absolute datings of mousterian settlements makes this correlation uncertain between 100 000 and 40 000 yr bp we now report dates obtained by thermoluminescence measurements of 34 specimens of burnt flint recovered from the upper 3 m of the mousterian deposits and from the superimposed upper palaeolithic layer the dates which range from 56 000 to 40 000 yr bp allow us to correlate the cold sediment deposits of le moustier with cold intervals of the oxygen isotopic record of the mediterranean sea during isotopic stage 3

graph theory recent developments of its application in geomorphology abstract applications of graph theory have proliferated across the academic spectrum in recent years whereas geosciences and landscape ecology have made rich use of graph theory its use seems limited in physical geography and particularly in geomorphology common applications of graph theory analyses of connectivity path or transport efficiencies subnetworks network structure system behaviour and dynamics and network optimization or engineering all have uses or potential uses in geomorphology and closely related fields in this paper we give a short introduction to graph theory and review previous geomorphological applications or works in related fields that have been particularly influential network like geomorphic systems can be classified into nonspatial or spatially implicit system components linked by statistical causal relationships and spatial units linked by some spatial relationship for example by fluxes of matter and or energy we argue that if geomorphic system properties and behaviour e g complexity sensitivity synchronisability historical contingency connectivity etc depend on system structure and if graph theory is able to quantitatively describe the configuration of system components then graph theory should provide us with tools that help in quantifying system properties and in inferring system behaviour

flint thermoluminescence dates from the cfr laboratory at gif contributions to the study of the chronology of the middle palaeolithic abstract flint tools are among the most durable objects marking the presence of prehistoric humans methodological advances of the last decade have made thermoluminescence of burnt flint a reliable dating tool and have provided new dates which require reassessment of the chronology of numerous middle palaeolithic sites dates for several near eastern sites show the presence of neanderthals from at least oxygen isotope stage 6 until after 50 ka ago and push the appearance of modern humans to before 100 ka ago long before their arrival in europe whether the two populations were present continuously or intermittently and precisely when they appeared is uncertain at the moment thermoluminescence results suggest that the mousterian lithic industries were introduced at about the same time in europe as in the near east with the difference that in the latter area this industry was used by early modern humans as well as by neanderthals the new tl chronology assigns a much longer life span to specific types of levantine mousterian lithic industries than previously believed finally new dates for the ch telperronian site of saint cesaire open up the possibility that the last neanderthals were still present after some cro magnons had already settled in western europe

14c activity and global carbon cycle changes over the past 50 000 years a series of 14c measurements in ocean drilling program cores from the tropical cariaco basin which have been correlated to the annual layer counted chronology for the greenland ice sheet project 2 gisp2 ice core provides a high resolution calibration of the radiocarbon time scale back to 50 000 years before the present independent radiometric dating of events correlated to gisp2 suggests that the calibration is accurate reconstructed 14c activities varied substantially during the last glacial period including sharp peaks synchronous with the laschamp and mono lake geomagnetic field intensity minimal and cosmogenic nuclide peaks in ice cores and marine sediments simulations with a geochemical box model suggest that much of the variability can be explained by geomagnetically modulated changes in 14c production rate together with plausible changes in deep ocean ventilation and the global carbon cycle during glaciation

geoarchaeology the four dimensional 4d fluvial matrix and climatic causality abstract geoarchaeology is the application of geological and geomorphological techniques to archaeology and the study of the interactions of hominins with the natural environment at a variety of temporal and spatial scales geoarchaeology in the uk over the last twenty years has flourished largely because it has gone beyond technological and scientific applications over the same period our ability to reconstruct the 3 dimensional stratigraphy of fluvial deposits and the matrix of fluvial sites has increased dramatically because of a number of technological advances these have included the use of lidar laser imaging and radar to produce high resolution digital surface models the use of geophysics particularly ground penetrating radar and electrical resistivity to produce sediment depth models and the use of gis and data visualisation techniques to manipulate and display the data these techniques along with more systematic and detailed sedimentological recording of exposed sections have allowed the construction of more precise 3 dimensional volumetric models of the matrix of artefacts within fluvial deposits additionally a revolution in dating techniques particularly direct sediment dating by luminescence methods has enabled the creation of 4 dimensional models of the creation and preservation of these sites these 4 dimensional models have the ability to provide far more information about the processes of site creation preservation and even destruction and also allow the integration of these processes with independent data sources concerning cultural evolution and climatic change all improvements in the precision of dating fluvial deposits have archaeological importance in our need to translate events from a sequential or geological timeframe to human timescales this allows geoarchaeology to make a more direct contribution to cultural history through the recognition of agency at the individual or group level this data can then form a component of biocomplexity or agent based modelling which is becoming increasingly used in the natural sciences particularly ecology and geomorphology and which can be used to test scenarios including the impact on and response of hominins to abrupt or catastrophic environmental change whilst catastrophic events clearly represent the atypical they can be illuminating in revealing cognitive processes resulting in abandonment coping mitigation and innovation these points are exemplified using two in depth case studies one from the holocene geoarchaeological record of the river trent in central england and the other from the palaeolithic record from rivers in south west britain in the former the interaction between climate change and human activity is illustrated at the year to century timescale whilst in the other the timescale is millennial these case studies have deliberately been chosen to be as different as possible in temporal and spatial scale with the aim of examining the applicability of methodological and theoretical aspects of geoarchaeology lastly the paper considers the problem of scale in geoarchaeology and concludes it is process dependency which ultimately affects the questions we can ask and that questions of human response to climate change are fundamentally a product of materiality and cognitive processes this demands an in depth contextual approach to such questions rather than database driven assertions of causality

the role of acids in electrical conduction through ice 1 electrical conduction through meteoric polar ice is controlled by soluble impurities that originate mostly from sea salt biomass burning and volcanic eruptions the strongest conductivity response is to acids yet the mechanism causing this response has been unclear here we elucidate conduction mechanisms in ice using broadband dielectric spectroscopy of meteoric polar ice cores we find that conduction through polycrystalline polar ice is consistent with jaccard theory for migration of charged protonic point defects through single ice crystals except that bulk dc conduction is impeded by grain boundaries neither our observations nor modeling using archie s law support the hypothesis that grain boundary networks of unfrozen acids cause significant electrolytic conduction common electrical logs of ice cores by electrical conductivity measurement ecm or dielectric profiling dep and the attenuation of radio waves in ice sheets thus respond to protonic point defects only this response implies that joint interpretation of electrical and chemical logs can determine impurity partitioning between the lattice and grain boundaries or inclusions for example in the greenland ice core project grip ice core from central greenland on average more than half of the available lattice soluble impurities h cl nh4 create defects understanding this partitioning could help further resolve the nature of past changes in atmospheric chemistry

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

patterns and processes of wood debris accumulation in the queets river basin washington field surveys in the 724 km 2 queets river basin on the west slope of the olympic mountains in nw washington reveal basin wide patterns of distinctive wood debris wd accumulations that arise from different mechanisms of wd recruitment hydraulic geometry and physical characteristics of wd individual pieces of wd in an accumulation or jam can be separated into key racked and loose members ten types of wd accumulations are identified based on the mode of recruitment and the orientation of key racked and loose debris relative to the channel axis although some types of wd accumulation have few geomorphic effects others form stable in stream structures that influence alluvial morphology at both subreach and reach length scales ranging from less than 1 to greater than 10 channel widths in the queets river stable accumulations of wd directly influence channel anabranching planform geometry flood plain topography and establishment of long term riparian refugia for old growth forest development the classification of wood debris accumulations in the queets river basin is based on physical observations that offer a template potentially applicable to other forested mountain regions d 2002 elsevier science b v all rights reserved

regional three dimensional seismic velocity model of the crust and uppermost mantle of northern california 1 we present a three dimensional 3d tomographic model of the p wave velocity vp structure of northern california we employed a regional scale double difference tomography algorithm that incorporates a finite difference travel time calculator and spatial smoothing constraints arrival times from earthquakes and travel times from controlled source explosions recorded at network and or temporary stations were inverted for vp on a 3d grid with horizontal node spacing of 10 to 20 km and vertical node spacing of 3 to 8 km our model provides an unprecedented comprehensive view of the regional scale structure of northern california putting many previously identified features into a broader regional context and improving the resolution of a number of them and revealing a number of new features especially in the middle and lower crust that have never before been reported examples of the former include the complex subducting gorda slab a steep deeply penetrating fault beneath the sacramento river delta crustal low velocity zones beneath geysers clear lake and long valley and the high velocity ophiolite body underlying the great valley examples of the latter include mid crustal low velocity zones beneath mount shasta and north of lake tahoe

current sierra nevada north america motion from very long baseline interferometry implications for the kinematics of the western united states we use geodetic measurements from very long baseline interferometry to estimate the motion of the sierra nevadan microplate which is composed of the sierra nevada and the great valley the motion of the sierra nevadan microplate relative to the north american plate is described by a right handed rotation of 0 61 m y about lat 32 n long 128 w this euler pole lies only 10 southwest of the sierra nevadan microplate and predicts a significant counterclockwise rotation about a local vertical axis it further predicts a velocity of the eastern edge of the sierra nevada at 38 0 n 119 3 w relative to stable north america of 11 1 mm yr toward n36 3 w quoted uncertainties are plus or minus one standard error which accounts for about one fourth of the velocity between the pacific and north american plates and is 25 clockwise of many prior estimates the velocity nearly parallels the boundary between the sierra nevada and the great basin which implies that current motion within the great basin results in a rotational noncoaxial deformation we use this velocity to estimate how motion is distributed across the broad deforming zone taking up pacific north america plate motion we find that the vector sum of strike slip along the san andreas fault and motion of the sierra nevada relative to stable north america taken up by deformation within the great basin differs little from the pacific north america plate velocity the difference can be described at 36 n along the san andreas fault by a vector of 6 mm yr directed toward n20 w this vector resolves into components of 5 mm yr parallel to the fault and 2 mm yr perpendicular to the fault with 95 confidence intervals of 0 to 10 mm yr and 1 to 5 mm yr respectively the component perpendicular to the fault is several times smaller than found in prior studies and places a small upper bound on fault perpendicular shortening we conclude that motion previously inferred to be taken up by deformation other than strike slip along the san andreas fault or deformation within the great basin is much smaller than previously thought

middle to upper palaeolithic site formation processes at the bordes fitte rockshelter central france transformation in technological patterns associated with the middle to upper palaeolithic transition between 50 and 40 ka in western europe and their relationship with the neanderthal and anatomically modern human populations and behaviors are issues that continue to stimulate heated debate in this article we use the middle and early upper palaeolithic archaeo stratigraphic record from the bordes fitte rockshelter les roches d abilly site central france a bayesian analysis of the ages obtained by accelerator mass spectrometry radiocarbon on ultrafiltered collagen and by luminescence on quartz and feldspar grains to establish a timeline for material culture and sedimentary dynamic changes during the middle to upper palaeolithic transition technology refitting studies and taphonomy of lithic artifacts recovered in the geoarchaeological field units d1 and d2 permit to characterize 3 reduction strategies levallois discoidal and ch telperronian blade that took place between the cold heinrich events 5 and 4 we discuss the implications of the results to characterize the end of the middle palaeolithic and for distinguishing anthropogenic and non anthropogenic factors in middle to upper palaeolithic assemblage s variability

synchronization and scale in geomorphic systems abstract geomorphic systems consist of coupled subsystems with traits of small world networks swn characterized by tightly connected clusters of components with fewer connections between the clusters geomorphic systems based on scale hierarchies often exhibit a connected caveman small world network ccswn structure swns are efficient for linking a large number of components with a relatively small number of links but effects of ccswn structure on synchronization and scale linkage have not been examined synchronization is analyzed via graph theory and applied to 1 relationships among three levels of form process interaction in stream channels 2 hierarchical relationships of weathering systems at scales from weathering profiles to landscapes and 3 interactions in fluviokarst systems at the scale of flow processes and of landscape evolution relationships among system components are represented as simple unweighted graphs the largest eigenvalue of the adjacency matrix spectral radius reflects the critical coupling strength required to synchronize the system the second smallest eigenvalue of the laplacian of the adjacency matrix algebraic connectivity is a measure of the synchronizability in all examples both are much less than the maximum for networks of the same number of nodes the sparseness of the networks is the major contributor to the low synchronization but the specific pattern of connections wiring is also significant where ccswn structures arise naturally they help explain how geomorphic effects are transmitted between disparate scales in the absence of obvious scale linkage where ccswns are an option for representation of geomorphic systems in models and data structures they will not improve scale linkage despite the efficiency of swns in other respects methods developed here can be applied to evaluating alternative spatial data structures or mapping strategies which either increase synchronization supporting a lumping or aggregation approach or decrease synchronization indicating disaggregation or splitting into scale hierarchies

ams 14c analysis of teeth from archaeological sites showing anomalous esr dating results abstract we have carried out ams radiocarbon analysis on two groups of samples the first one gave reasonable esr age estimates and the second one yielded serious age underestinations all samples were supposedly older than 35 ka the oldest being around 160 ka two pretreatment techniques were used for radiocarbon dating acid evolution and thermal release heating to 600 750 and 900 c combined with total de gassing at these temperatures was chosen to obtain age estimates on the organic fraction secondary carbonates and original carbonate present in the hydroxyapatite mineral phase respectively all radiocarbon results present serious age underestimations the secondary carbonate fraction gives almost modern results indicating an extremely rapid exchange of this component owing to this very rapid carbonate exchange it is not likely that the esr signals used for dating are associated with the secondary carbonates one tooth from tabun with independent age estimates of 150 ka was further investigated by the oxford ams laboratory yielding an age estimate of 1930 100 bp on the residual collagen from dentine and 18 000 160 bp on the carbonate component of the enamel bioapatite we did not however find an explanation of why some samples give serious esr underestimatioils whilst many others provide reasonable results

crustal deformation across the sierra nevada northern walker lane basin and range transition western united states measured with gps 2000 2004 1 global positioning system gps data collected in campaigns in 2000 and 2004 were processed and interpreted with other gps data in the western basin and range province to provide new constraints on the rate style and pattern of deformation of the central and northern walker lane wl which lies near the western boundary of the basin and range across the central wl near 38n latitude the velocities with respect to north america increase westward by 10 mm yr inducing dextral shear farther north between 40 and 41n latitude a western zone of 7 mm yr relative motion undergoes dextral shear and an eastern zone of 3 mm yr relative motion undergoes extension and shear these data show that the northern wl is essentially a dextral shear zone experiencing minor net dilatation ed 2 6 0 8 nstrain yr near most holocene normal faults dilatation inferred from the velocity field is not greater than the uncertainties however near the central nevada seismic belt we detect significant dilatation expressed as extension in a direction approximately normal to the range fronts ed 23 0 3 9 nstrain yr some of which is attributable to transient postseismic deformation following large historic earthquakes a block model constrained by velocities corrected for transient effects shows that the sum of dextral slip rates across the honey lake warm springs east pyramid fault system and mohawk valley faults is 7 mm yr the wl is a zone whose width and dilatation rate increase northwestward consistent with counterclockwise rotation of the sierra nevada microplate and transfer of deformation into the pacific northwest

development of spatial pattern in large woody debris and debris dams in streams the spatial distribution of large woody debris lwd in streams was evaluated using neighbor k statistics following extensive wood deposition from an ice storm in the eastern adirondack mountains new york two years after wood deposition we surveyed individual pieces of lwd in one stream and surveyed debris dam locations in eight streams within the ice storm area to examine the linear pattern of debris dams within a stream we used a one dimensional version of ripley s k a second order statistic that evaluates the spatial pattern of points within a landscape both aggregated and segregated regularly spaced distributions of wood were identified individual pieces of lwd were aggregated at spatial extents ranging from 0 to 40 m and were segregated at spatial extents ranging from 80 to 100 m in two streams we found that debris dams were segregated at distances ranging from 100 to 300 m relative to randomly chosen locations but debris dams showed no significant spatial pattern in six other study streams previous studies of wood distribution in streams have not observed segregated distribution patterns spatial segregation of debris dams in the study area likely occurred in response to regularly spaced stream features or processes that allow movement of individual pieces of lwd toward more stable accumulation points neighbor k statistics can be used to identify and describe spatial pattern in large woody debris and such patterns can be used to help evaluate and identify processes responsible for their generation

extinction chronology of the woolly rhinoceros coelodonta antiquitatis in the context of late quaternary megafaunal extinctions in northern eurasia abstract megafaunal extinctions in northern eurasia excluding mediterranean islands since the last interglacial claimed about 37 of species with body weights 44 kg here we review the dating evidence for the timings of these extinctions which were staggered over tens of millennia moreover individual species disappeared at different times in different geographical areas for example cave bear probably disappeared ca 30 5 28 5 ka at approximately the onset of gs 3 beginning of lgm whereas cave lion survived until the lateglacial ca 14 ka others survived into the holocene woolly mammoth until ca 10 7 ka in the new siberian islands and ca 4 ka on wrangel island giant deer to at least 7 7 ka in western siberia and european russia it is evident that climatic and vegetational changes had major impacts on species ranges and moreover the contrasting chronologies and geographical range contractions are consistent with environmental drivers relating to their differing ecologies however the possible role of humans in this process has still to be satisfactorily explored we present a detailed review of the radiocarbon record and extinction chronology of an exclusively northern eurasian species the woolly rhinoceros coelodonta antiquitatis an animal adapted to feeding on low growing herbaceous vegetation and a dry climate with minimal snowfall during the last glacial the overall time averaged range of c antiquitatis extended across most of northern eurasia but the species failed to reach north america on the basis of 233 ultrafiltered ams radiocarbon dates together with 50 others which pass our auditing criteria we reconstruct a detailed chronology for this species c antiquitatis was widespread over most of the time span covered by radiocarbon dating but from ca 35 ka calibrated it apparently contracted towards the east culminating in its probable extinction ca 14 ka with the latest dates from north eastern siberia it disappeared from britain at the western more oceanic end of its range at ca 35 ka bp apparently corresponding with the onset of interstadial gi 7 in north eastern siberia c antiquitatis survived through much of gi 1d e and probably went extinct at or close to the onset of gi 1c allerod ca 13 9 ka bp its final extinction probably relates to lateglacial interstadial warming and increased precipitation especially snowfall accompanied by the replacement of low growing herbaceous vegetation by shrubs and trees the survival of woolly rhinoceros in north eastern siberia when it had disappeared further west may relate to the later persistence of open vegetation in that region the timing of its final extinction could relate to the fact that the lateglacial interstadial was significantly warmer than any other event in the previous 50 millennia there are indications of gaps in the pattern of dates in certain areas that may have significance in terms of temporary absences of c antiquitatis some of which may correspond to interstadial phases the radiocarbon record of c antiquitatis is still poor in some potentially important areas and further work will corroborate or reject the hypotheses of regional gaps in occurrence and might perhaps reveal currently unsuspected later survival

wood storage within the active zone of a large european gravel bed river wood storage within the active zone of the dynamic gravel bed fiume tagliamento italy was investigated at eight sites along the river s main stem the quantity nature and mode of wood storage revealed a number of trends related to active zone morphology cover type and distance from the river s source relatively small quantities of wood were stored on open gravel surfaces estimates ranged from 1 to 21 t ha 1 intermediate quantities were associated with established islands 24 186 t ha 1 and large quantities were associated with pioneer islands 293 1664 t ha 1 thus variations in the geomorphological style of the river which are associated with changes in these three cover types are reflected in variations in the amount of wood that is stored in different reaches in addition although wood was found in many locations within the active zone it was preferentially stored in three specific locations i bar crests the main open gravel location for wood accumulations and pioneer islands ii the margins and iii surfaces of established islands the proportion of the stored wood that was living sprouting increased downstream and was higher on the open gravel than in association with established islands there was a downstream gradient in the dominant type of wood accumulation individual logs predominated at the most upstream site thereafter on the open gravel whole shrubs and trees dominated the more confined sites in the headwaters and middle reaches whereas jams were the most frequent form of accumulation in the downstream reaches jams were the most frequent type of accumulation associated with established islands throughout the river in contrast to small streams where debris dams constitute the major type of wood accumulation complex patterns and trends of wood storage were revealed along the tagliamento although further studies are needed it is clear that erosion of woody vegetation its subsequent transport and deposition play a major role in structuring the geomorphological and ecological character of this relatively natural large european river system insight into the mechanisms underlying the observed spatial patterns will contribute to a better understanding of the dynamic processes involved and is essential for more effective management of river ecosystems

radiometric dating of the middle palaeolithic tool industry and associated fauna of pin hole cave creswell crags england uranium series dating of derived speleothem suggests that the sediments enclosing a middle palaeolithic stone artefact assemblage in pin hole cave probably accumulated after about 64 ka and 14c dates indicate a likely age of 40 ka for the large mammal fauna associated with it electron spin resonance data from the fauna conform with these age constraints and are consistent with accumulation between 38 and 50 ka this evidence supports the view that britain was recolonised by hominids during oxygen isotope stage 3 stratigraphically higher stone tool industries demonstrate the local presence of both early upper and late upper palaeolithic cultures 1998 john wiley sons ltd

testing of a single grain osl chronology across the middle to upper palaeolithic transition at les cottes france abstract the timing of the middle palaeolithic to upper palaeolithic transition in france is important to help understand when where and how neanderthals have been replaced by homo sapiens radiocarbon dating has been the dating workhorse in constructing the chronological framework pertinent to these questions in this study we are testing whether single grain osl dating has the accuracy and precision to be useful as a complementary dating method the site of les cottes provides an ideal testing ground because of its stratigraphic integrity and reliable radiocarbon chronology we applied single grain osl dating of quartz to 19 samples and multi aliquot met pirir dating of potassium rich feldspar grains to 5 samples to explicitly test assumptions of pre depositional resetting of the osl signal and post depositional exposure to variable beta dose rates the good agreement between the single grain osl and the multi aliquot met pirir ages suggest that the optical signals of both quartz and feldspar grains were reset prior to deposition and that much of the extra scatter observed in the equivalent dose distribution of quartz grains are likely due to the small scale differences in beta dose delivered to individual grains both the quartz osl and feldspar met pirir ages show great consistency with the 14 c ages on bone collected from the same units this gives confidence in the measurement and analytical approaches used to derive both the equivalent dose and dose rate the numerator and denominator respectively of the luminescence age equation these results suggest that a systematic and detailed single grain osl dating study can have the accuracy and precision that is necessary to play a powerful role in the dating of the middle and upper palaeolithic transition and other questions of importance in this time range and geographical area

seismogenic deformation between the sierran microplate and oregon coast block california usa the sierran microplate is a northwest translating block entrained in distributed motion east of the pacific plate to the north the oregon coast block ocb moves northward within the hanging wall of the cascadia subduction zone above the obliquely converging juan de fuca plate analysis of gps velocity data indicates that relative motion between the rigid sierran and ocb microplates is characterized by several millimeters per year of dextral shear directed n70 w which is distinct from and counterclockwise to macroscopic dextral shear in the walker lane east of the sierran microplate we present a new analysis of focal mechanisms from small earthquakes in an 80 km wide zone that spans the geodetically defined sierran ocb boundary to evaluate patterns of distributed deformation we find that the direction of macroscopic dextral shear in this region is parallel to sierran ocb motion derived from gps data the seismogenic deformation is consistent with postulated dextral shear within an incompletely studied west northwest trending zone of faults and lineaments that traverses the northern sierra nevada the faults and lineaments terminate westward against quaternary folds in the northern sacramento valley active deformation at the sierran ocb boundary accommodates the relative motion of the bounding microplates and probably does not represent discrete transfer of walker lane motion to the cascadia subduction zone in a restraining left step across the northern sierra and sacramento valley

the complementarity of luminescence dating methods illustrated on the mousterian sequence of the roc de marsal a series of reindeer dominated quina mousterian layers dated to mis 3 abstract located in southwest france roc de marsal is a cave with a rich mousterian stratigraphic sequence the lower part of the sequence layers 9 5 are characterized by assemblages dominated by levallois lithic technology associated with composite faunal spectra including red deer roe deer and reindeer that shows a gradual increase in the frequency of reindeer the top of the sequence layers 4 2 are characterised instead by quina lithic technology both in terms of technology and typology with the faunal remains dominated by reindeer roc de marsal thus provides a very interesting case study to place behavioural changes in a context of changing climates and environments in western europe during the late pleistocene to link the occupations at roc de marsal with global and regional climatic conditions known independently a robust chronology is needed with this aim in mind we applied three luminescence dating methods tl osl and irsl on different minerals flint quartz and k feldspar extracts here the results of two of these methods are presented in detail tl and osl and compared with preliminary irsl data at roc de marsal a comparison of methods was necessary to overcome a complex sedimentary history with very heterogeneous dose rate distributions both at the beta mm and gamma dm dose rate scales the results indicate that the lower levallois layers are dated to 65 70 ka while overlying quina layers are dated to 49 ka these ages for the lower layers fit well with some models that place mixed faunal assemblages in the initial mis 4 however while the quina ages overlap with several other quina assemblages from the region they place the reindeer dominated fauna well after the peak cold of mis 4 and suggest a more extended and complex period of contemporaneous lithic techno complexes than posited by some current models

neanderthals in the outermost west technological adaptation in the late middle palaeolithic re colonization of britain marine isotope stage 4 3 abstract despite its long research history and particular palaeogeographic context the british late middle palaeolithic lmp of marine isotope stage 4 and 3 has not been fully integrated in broader discussions of neanderthal behavioural adaptations this is due not only to the lack of a comprehensive account of the archaeological record but also to perceptions that the numerically small character of the record itself and its position at the margins of the neanderthal world are unpromising research contexts this paper addresses the first problem by reporting results from a study of the british lmp lithic assemblages most securely assigned to late mis 4 and mis 3 using a technologically focused approach designed to derive the maximum information from the available material the results suggest a coherent and broadly uniform techno economic system characterised by clear raw material selectivity and high levels of mobility bifaces and scrapers are common and show strong evidence for curation transportation and maintenance discoid centripetal and alternate core reduction methods occur alongside more informal approaches with virtually no evidence for levallois this new data equally demonstrates the relevance of the british lmp to current questions about the diversity of later neanderthal techno economic organisation additionally as this record is the only clearly defined example of a middle palaeolithic colonisation in europe this study provides an opportunity to examine associated behavioural adaptations within the mammoth steppe ecosystem of mis 3

the early lateglacial re colonization of britain new radiocarbon evidence from gough s cave southwest england abstract gough s cave is still britain s most significant later upper palaeolithic site new ultrafiltered radiocarbon determinations on bone change our understanding of its occupation by demonstrating that this lasted for only a very short span of time at the beginning of the lateglacial interstadial greenland interstadial 1 gi 1 bolling and allerod the application of bayesian modelling to the radiocarbon dates from this and other sites from the period in southwest england suggests that re colonization after the last glacial maximum took place only after 14 700 cal bp and is therefore more recent than that of the paris basin and the belgian ardennes on their own the radiocarbon determinations cannot tell us whether re colonization was synchronous with just prior to or after lateglacial warming isotopic studies of humanly modified mammalian tooth enamel may be one way forward

intra level technological change and its implications for mousterian assemblage variability the example of le moustier layer g revealing the multiple factors underlying variability observed in middle palaeolithic lithic assemblages of southwestern france continues to be of great interest dividing scholars both in terms of their interpretation and the approaches applied building sound interpretive models whether in terms of chronology or techno economy is however often hindered by the nature of recovery strategies employed during many early excavations in this important region the site of le moustier lower shelter has played a fundamental role in the definition of the well known and controversial mousterian facies as well as the perception of their chronological patterning based on a technological and taphonomic analysis of material recovered from a small test pit it has recently been shown that the original lithic collections recovered from le moustier by peyrony before the first world war are unrepresentative and that clear technological variations exist that were otherwise undetectable in this brief contribution we present additional data concerning newly discovered material from layer g assigned by bordes to his mta type a variant this material further supports the previously documented separation of a lower levallois dominated assemblage from the overlying one with a heavy emphasis on bifacial shaping faconnage finally these results are discussed in terms of broader definitional issues of middle palaeolithic techno complexes focussing specific attention on assemblages with bifacial tools

ipswichian fauna of victoria cave and the marine palaeoclimatic record the lack of age dating methods which can be applied beyond the limit of radiocarbon dating makes the global correlation of continental climatic events and stratigraphic sequences with the continuous palaeoclimate record obtained by isotopic and faunal analysis of deep sea sediment cores1 3 a difficult task often only a relative time scale can be obtained using complex and perhaps tenuous litho and biostratigraphical data speleothems may assist in this correlation for embodied in their calcium carbonate structures are elemental and isotopic variations which indicate both their age and climatic conditions prevailing during their deposition speleothems may be reliably dated by the 230th 234u method to an age of 350 kyr bp providing they consist of non porous unrecrystallized calcite which is essentially free of clastic detrital sediments4 6 they may also provide palaeoclimatic information for previously glaciated areas 1 because their presence indicates that groundwater movement was not prevented by ice formation at the surface and co2 was produced in the soil zone by root respiration and plant decay limestone bedrock may then be dissolved and reprecipitated as speleothems in caves below the surface and 2 because of the variations in stable isotopic content and fluid inclusion waters contained therein4 7 8 additional climatic and chronological information may be obtained where speleothems are interstratified with deposits characteristic of a particular climatic regime and with deposits containing organic remains we describe here the results of dating speleothems encrusting the remains of mammals from victoria cave in northern england and discuss their significance in terms of the correlation between continental and oceanic palaeoclimatic records

a formal mammalian biostratigraphy for the late pleistocene of britain abstract a series of distinctive mammalian assemblages spanning much of the british late pleistocene is defined on the basis of type localities and a formal biozonation proposed the joint mitnor cave mammal assemblage zone includes the famous hippopotamus fauna of the early part of the last interglacial complex oxygen isotope substage 5e this is succeeded by the bacon hole mammal assemblage zone in which hippopotamus is no longer present and species like mammoth roe deer and northern vole re enter the british region this assemblage zone appears to represent the later substages of ois 5 a faunal grouping dominated by bison and reindeer is named the banwell bone cave mammal assemblage zone and is believed to correlate closely with the early devensian ois 4 the pin hole mammal assemblage zone includes the familiar mammoth steppe faunas of the middle devensian ois 3 dominated by horse woolly rhinoceros and mammoth the lateglacial interstadial is characterized by the gough s cave mammal assemblage zone in which horse red deer and humans are well represented part of ois 2 no definitive evidence for human activity can be found for a period spanning the last interglacial complex ois 5 and the early devensian ois 4 human populations return to britain with the pin hole mammal assemblage zone fauna during the middle devensian ois 3 and reappear after the dimlington stadial during the late devensian ois 2 but in a different faunal association

erratum to rupture process of the 2019 ridgecrest california mw 6 4 foreshock and mw 7 1 earthquake constrained by seismic and geodetic data

steady rotation of the cascade arc displacement of the miocene cascade volcanic arc northwestern north america from the active arc is in the same sense and at nearly the same rate as the present clockwise block motions calculated from gps velocities in a north american reference frame migration of the ancestral arc over the past 16 m y can be explained by clockwise rotation of upper plate blocks at 1 0 m y over a linear melting source moving westward 1 4 5 km m y due to slab rollback block motion and slab rollback are in opposite directions in the northern arc but both are westerly in the southern extensional arc where rollback may be enhanced by proximity to the edge of the juan de fuca slab similarities between post 16 ma arc migration paleomagnetic rotation and modern gps block motions indicate that the secular block motions from decadal gps can be used to calculate long term strain rates and earthquake hazards northwest directed basin and range extension of 140 km is predicted behind the southern arc since 16 ma and 70 km of shortening is predicted in the northern arc the gps rotation poles overlie a high velocity slab of the siletzia terrane dangling into the mantle beneath idaho united states which may provide an anchor for the rotations

high resolution analysis of uranium and thorium concentration as well as u series isotope distributions in a neanderthal tooth from payre ardeche france using laser ablation icp ms we have mapped u 238 u and th 232 th elemental concentrations as well as u series isotope distributions in a neanderthal tooth from the middle palaeolithic site of payre using laser ablation icp ms the u concentrations in an enamel section varied between 1 and 1500 ppb the u concentration maps show that u migration through the external enamel surface is minute the bulk of the uranium having migrated internally via the dentine into the enamel the uranium migration and uptake is critically dependent on the mineralogical structure of the enamel increased u concentrations are observed along lineaments some of which are associated with cracks and others may be related to intra prismatic zones or structural weaknesses reaching from the dentine into the enamel the uranium concentrations in the dentine vary between about 25 000 and 45 000 ppb our systematic mapping of u concentration and u series isotopes provides insight into the time domain of uaccumulation most of the uranium was accumulated in an early stage of burial with some much later overprints none of the uranium concentration and u series profiles across the root of the tooth complied with a single stage diffusion adsorption d a model that is used for quality control in u series dating of bones and teeth nevertheless in the domains that yielded the oldest apparent u series age estimates u leaching could be excluded this means that the oldest apparent u series ages of around 200 ka represent a minimum age for this neanderthal specimen this is in good agreement with independent age assessments 200 230 ka for the archaeological layer in which it was found the th elemental concentrations in the dental tissues were generally low between about 1 and 20 ppb and show little relationship with the nature of the tissue 2008 elsevier ltd all rights reserved

an absolute chronology for the raised beach and associated deposits at sewerby east yorkshire england the raised beach sediments revealed in the cliffs at sewerby east yorkshire are widely regarded as ipswichian in age previously reported evidence for this dating is reviewed and new results from a range of luminescence dating techniques applied to the blown sand deposit overlying the raised beach are reported these provide the first absolute date for the sewerby site of 120 84 11 82 ka which places the blown sand at the boundary between oxygen isotope stages ois 5e and 5d as the underlying raised beach is little older than the blown sand it probably formed during ois stage 5e as suggested by the faunal evidence

hayonim cave a tl based chronology for this levantine mousterian sequence the thermoluminescence dating method was applied to 77 heated flints from the mousterian layers of hayonim cave in order to provide a precise tl based chronology for this important levantine sequence a detailed dosimetric study was performed by using 76 dosimeter capsules and revealed strong spatial dose rate variations in parallel fourier transform infrared spectrometry enabled the identification of various mineral assemblages in the sediments of the cave and to localize the boundaries of these assemblages by comparing these two data sets it is shown that low dose rate values w500 mgy a are systematically recorded in areas where the calcite dahllite cd assemblage is preserved whereas higher values up to 1300 mgy a are associated with the leucophosphite montgomeryite variscite and siliceous aggregates lmvs assemblage the dosimetric and mineralogical information was combined in order to assess where possible the dose rate experienced by each flint during its burial some of the flint samples analyzed were too close to mineral assemblage boundaries and were therefore discarded this rigorous selection led to tl ages ranging from 230 to 140 ka for the lower part of the mousterian sequence layers f and lower e which contains lithic industries characterized by blade production using the laminar method 2006 elsevier ltd all rights reserved

identifying the spatial pattern of wood distribution in northeastern north american streams article i nfo the spatial distribution of instream wood influences important ecological processes but has proven challenging to describe quantitatively we present a modified version of a previously described metric used to quantify the spatial extent and pattern of instream wood distribution then apply this approach in evaluating the distribution of wood habitat in forested northeastern north american streams this revised metric a binned neighbor k analysis provides greater resolution in evaluating the presence of aggregated periodic or segregated wood distributions in stream ecosystems we employed this metric in evaluating the distribution of wood within 17 streams in two regions of northeastern north america our results indicate that the binned neighbor k approach more accurately represents the spatial extent at which wood accumulates in streams by identifying recurring intervals in streams within which instream wood is not present and by more accurately quantifying the spatial extent of wood aggregations and periodically repeating occurrences of accumulated wood we also used this metric to quantify the overall extent of wood organization in streams which revealed similarities and differences in instream wood distribution patterns in the two regions evaluated wood distribution patterns in both study regions were generally consistent with our expectations of increased organization at an intermediate stream size up to 10 m bankfull width then in larger streams n10 m wood was less organized these observed patterns result from landscape and ecosystem influences upon wood accumulation and movement in streams

revised radiocarbon ages on woolly rhinoceros coelodonta antiquitatis from western central scotland significance for timing the extinction of woolly rhinoceros in britain and the onset of the lgm in central scotland woolly rhinoceros bones from a number of sites in britain have been ams radiocarbon dated following ultrafiltration pre treatment these determinations give a coherent set of ages between 50 and c 35 cal ka bp the youngest 35 864 34 765 cal bp come from the area around bishopbriggs in western central scotland and are derived from glaciofluvial sand and gravel overlain by till both deposited during the last glacial maximum lgm glaciation a previous radiocarbon date from the site suggested that woolly rhinoceros lived c 27 14c ka bp and the region was ice free at the time this date has had significant influence on the timing of extinction of woolly rhinoceros and the onset of glaciation over britain during the lgm the new dates revise this earlier determination and confirm that woolly rhinoceros became extinct in britain after c 35 cal ka bp that central scotland was ice free at this time and glaciation extended across this region sometime after 35 cal ka bp

present tectonic motion across the coast ranges and san andreas fault system in central california geodetic results from very long baseline interferometry vlbi satellite laser ranging slr and the global positioning system gps are used to estimate angular velocities between the sierran microplate pacific plate and north american plate the sierra pacific pole of rotation lies nearer to the san andreas fault than does the pacific north america pole of rotation and leads to different tectonic implications than if the latter is used the angular velocities show that the san andreas fault system and central california coast ranges accommodate motion of 39 2 mm yr mainly by strike slip faulting all confidence limits following signs in this paper are 95 confidence limits fault normal motion is small is mainly convergent at rates up to 3 3 1 0 mm yr and varies along the coast but is divergent at 2 6 1 2 mm yr across san pablo bay and associated topographic lows across which the sierran and central valley watershed drains to the pacific ocean the mountain ranges tend to be larger where the fault normal convergence rates are larger the low convergence rate 0 5 1 8 mm yr normal to the san andreas fault in the carrizo plain differs sharply from that previously inferred 8 2 1 2 mm yr and 4 9 1 6 mm yr by feigl et al 1993 the difference is due to differences between their and our elastic strain accumulation models and between how their and our pacific plate reference frames are defined the ranges in most places require a minimum of 4 2 1 m y of fault normal convergence at the present rate to attain their present cross sectional area if erosion is neglected more if it is not the amount of convergence previously estimated from a balanced cross section across the diablo range in central california requires 10 8 3 m y of convergence at the present rate the former is consistent with widely held views about the onset of the coast range orogeny but the latter is not both are consistent however with the recent plate reconstructions by s cande j stock and colleagues which indicate that pacific plate motion relative to north america changed to a more convergent direction 20 25 clockwise of its prior direction at ca 8 to 6 ma and not at 3 5 ma as had been previously inferred the inferred change in direction of plate motion is large compared with the present angle of convergence across the straight and narrow segment of the san andreas fault of 0 7 4 7 from which we infer that the sierran microplate changed motion relative to north america at the same time ca 8 to 6 ma as did the pacific plate we further infer that the motion accommodated across the great basin must also have changed at the same time we also examine the hypothesis that stable sliding occurs along the san andreas fault and other northwest striking strike slip faults in central california where the fault normal convergence rate is low or negative and that these faults are unstable where the fault normal convergence rate is high such a relationship appears to hold in general but fails in detail in particular there are substantial sections of fault with small inferred rates of fault normal convergence across which the san andreas fault is locked moreover the creeping section of the san andreas fault i e the section between parkfield and the calaveras junction is the locus of greater fault normal convergence 3 2 1 4 mm yr than is the locked part of the fault 0 5 1 8 mm yr south of parkfield thus this hypothesis is at best a partial explanation for the observed distribution of locked and nonlocked sections of the fault

the late glacial reoccupation of the british isles and the creswellian this paper presents a review of ams radiocarbon dating evidence for human occupation of britain during the late glacial interstadial the dates are all on humanly modified materials including artefacts and on human bone the calpal program is used to test whether the earliest evidence of human presence shows any correlation with more widespread climatic events and if the british chronology differs significantly from that of neighbouring regions of northwest europe in the second part of the paper a number of well dated sites with british late upper palaeolithic creswellian technology are examined and compared with lithic assemblages from the netherlands and belgium the main conclusions of this work are that expansion of human populations into the northern edge of the upland zone just before or at the beginning of gi 1 was followed by repopulation of the british isles possibly with very little time lag the british creswellian sites offer evidence of this earliest resettlement which is mainly focused on the upland margins of western and central britain copyright 2003 john wiley sons ltd