pre grenvillian and grenvillian lithotectonic regions in eastern labrador correlations with the sveconorwegian orogenic belt in sweden the trans labrador batholith groswater bay terrane and lake melville terrane are three major crustal segments located adjacent to or within the grenville province in eastern labrador each crustal segment is a distinct lithotectonic entity displaying contrasts with each other in proportions of rock types structural style and metamorphic imprint together they indicate a unilateral polarity to the region partly reflecting grenvillian tectonism which sliced the region into thrust bound blocks in all three crustal segments an archean or aphebian gneissic basement is inferred onto or adjacent to which ca 1900 1700 ma supracrustal rocks were deposited deformation metamorphism and granitoid pluton emplacement were partly coeval with and partly postdated the supracrustal assemblages in the north tectonothermal effects can be assigned to hudsonian ketilidian orogenesis but their peak was 50 100 ma later farther south post tectonic granitoid plutons and layered mafic intrusions were emplaced at about

restrictions on fluorine depth profiling for exposure age dating in archaeological bones archaeological fragments of bone and teeth that are exposed to a humid environment take up fluorine from the surrounding soil the fluorine ion replaces the hydroxyl group in the mineral phase of the bone forming chemically more stable fluorapatite in cortical parts of the long bone diaphysis a fluorine concentration profile can be observed which decreases from the outer surface and the marrow cavity towards the inner parts of the bone matrix geological time spans are needed for this process to reach equilibrium and for the distribution to become uniform as the shape of the profile which can be described by a diffusion model contains information on the exposure duration of the fossil object several attempts to use fluorine profiling as a dating method have been undertaken the distribution of fluorine in an archaeological sample however is strongly influenced by environmentally induced processes of bone diagenesis i e alteration in the structure and composition of the mineral phase and degradation of organic components that may make the time information indistinct the primary chemical composition of bones can thus be obscured by diagenesis within tens hundreds or thousands of years this depends more on the diagenetic environment than on the geological age to observe the impact of environmental influence on the profile shape samples from several burial sites featuring various soil conditions have been analyzed for their fluorine distribution and preservation state this paper provides an overview on the restrictions that have to be considered when attempts are undertaken to relate a fluorine diffusion pattern to the archaeological age of a bone specimen

late quaternary stratigraphy and sedimentology of orphan basin implications for meltwater dispersal in the southern labrador sea abstract orphan basin is a deep water basin on the continental margin off newfoundland which throughout the late quaternary received proglacial sediment from local ice that crossed the continental shelf sediment from more distant sources was transported southward in the labrador current as proglacial plumes and in icebergs five sedimentary facies related to glacial processes are distinguished in cores recovered from orphan basin hemipelagic sediment nepheloid layer deposits layered mud beds rich in ice rafted detritus ird sand and mud turbidites and glaciogenic debris flow deposits ird rich beds correspond to periods of intensified iceberg calving and layered mud turbidites and glaciogenic debris flow deposits with glacial meltwater discharge in the late wisconsinan eight periods of meltwater discharge and iceberg calving from the newfoundland ice sheet are interpreted from the sediment facies in orphan basin these discharges coincide with the terminations of the colder periods of the d o cycles recorded in greenland ice cores the oldest minor meltwater event 27 5 28 5 cal ka corresponds to the first late wisconsinan ice advance across the grand banks and ne newfoundland shelf the following three meltwater discharges 23 23 5 23 8 24 5 and 25 27 cal ka deposited sand turbidites and glaciogenic debris flow deposits seaward of trinity trough which was occupied by an ice stream at this time and mud turbidites in the southern part of the basin derived from a mid shelf ice margin on the grand banks four periods of meltwater discharge occurred during the deglaciation and are centered at 15 18 5 19 75 and 20 75 cal ka the youngest is correlated to heinrich event 1 in the literature the 18 5 and 20 75 cal ka events have been recorded in multiple glacial settings in the north atlantic and therefore are interpreted as large scale events of meltwater discharge and iceberg calving but in orphan basin the 19 75 cal ka event is also of similar scale

bone and enamel diagenesis from the crystal to the environment a tribute to jean francois saliege a universite de lyon france cnrs france ecole normale superieure de lyon site monod 15 parvis rene descartes bp7000 lyon f 69342 france universite claude bernard lyon 1 43 bd du 11 novembre 1918 f 69622 villeurbanne cedex france b museum national d histoire naturelle cnrs departement ecologie et gestion de la biodiversite usm 303 umr 7209 du cnrs archeozoologie archeobotanique societes pratiques et environnements case postale 56 55 rue buffon f 75231 paris cedex 05 france

isotope compositions c o sr nd of vertebrate fossils from the middle eocene oil shale of messel germany implications for their taphonomy and palaeoenvironment abstract the middle eocene oil shale deposits of messel are famous for their exceptionally well preserved articulated 47 myr old vertebrate fossils that often still display soft tissue preservation the isotopic compositions o c sr nd were analysed from skeletal remains of messel s terrestrial and aquatic vertebrates to determine the condition of geochemical preservation authigenic phosphate minerals and siderite were also analysed to characterise the isotope compositions of diagenetic phases in messel diagenetic end member values of the volcanically influenced and due to methanogenesis 12 c depleted anoxic bottom water of the meromictic eocene maar lake are isotopically very distinct from in vivo bioapatite values of terrestrial vertebrates this unique taphonomic setting allows the assessment of the geochemical preservation of the vertebrate fossils a combined multi isotope approach demonstrates that enamel of fossil vertebrates from messel is geochemically exceptionally well preserved and still contains near in vivo c o sr and possibly even nd isotope compositions while bone and dentine are diagenetically altered enamel of the hippomorph perissodactyl propalaeotherium has low 13 c values 9 0 7 typical for c 3 plant feeders dentine of the same teeth has 13 c values 15 17 higher amongst the highest 13 c bioapatite values reported for terrestrial vertebrates this reflects diagenetic carbonate exchange with the strongly 12 c depleted anoxic lake bottom water enamel 87 sr 86 sr values 0 711 0 001 are consistent with propalaeotherium feeding on palaeozoic bedrocks surrounding lake messel and suggests that the basaltic tuff ring around the maar was already eroded 640 ka after its formation dentine has however much lower volcanically influenced 87 sr 86 sr 0 706 due to diagenetic sr uptake from the lake water oil shale enamel 18 o p values 18 0 6 of propalaeotherium are 2 3 lower than those of bones and scales of aquatic vertebrates that lived in the 18 o enriched lake water using transfer functions a 18 o h 2 o value of 5 1 for meteoric water and a mat of 18 2 5 c were reconstructed for messel

spatial variation of biologically available strontium isotopes 87sr 86sr in an archipelagic setting a case study from the caribbean this paper presents the results of strontium sr isotope analysis of modern and archaeological animal remains and modern plant samples from the caribbean region the goal is to assess if patterns of human mobility can be determined from the archaeological record in an archipelagic setting the range of variability and spatial distribution of biologically available strontium isotope signatures is reported and data evaluated to determine if sufficient heterogeneity exists to permit the identification of mobility despite the presence of potentially large contributions of marine strontium in island and coastal ecosystems the is landscape is divided into several sub regions based on the age and lithology of underlying geology and the variability of

maize mounds and the movement of people isotope analysis of a mississippian fort ancient region abstract the development of farming traditions has long interested archaeologists worldwide the relationship between this process and human movement has become increasingly well defined in recent years here we examine this issue in a case study concerning the longstanding question of the spread of maize agriculture and mississippian cultural traditions throughout much of the eastern u s although it has long been common to interpret the spread of mississippian maize agriculture partially as a result of human migration there have been very few direct studies of the question we do so here by analyzing human tooth enamel from burials for 87sr 86sr and 13c our results suggest that fort ancient societies adopted maize agriculture quickly with high levels of consumption at early sites the intensity of maize consumption declined over time however in contrast to the current model there is evidence for the presence of non local individuals at early fort ancient sites particularly turpin with the majority likely attributable to neighboring mississippian regions these developments occurred at some of the larger fort ancient sites by the mouths of the great and little miami rivers in ohio where the most abundant evidence for mississippian house styles and objects is concentrated

solubility profiles of synthetic apatites and of modern and fossil bones abstract strontium has been shown to vary within trophic levels in natural foodwebs so that previous criteria used to identify biogenic strontium in fossils namely consistent differences between herbivores and carnivores may be inappropriate in this article two alternative approaches are explored these include first experimental studies of the behaviour of synthetic apatites in the solubility profile system and second solubility profile studies of fossils from the pleistocene site of swartkrans the synthetic apatite studies show that simple mixtures of apatites dissolve discretely in the system study of swartkrans specimens reveals that while diagenetic sr is clearly present some recoverable sr varies in a manner similar to that seen in modern african foodwebs and is therefore unlikely to be of diagenetic origin

late ordovician chatfieldian catastrophic volcanism and abrupt carbonate platform interior subsidence a tectonic link across a taconian foreland basin quebec embayment due to inherited crustal weakness the late ordovician trenton group of new york state and equivalent strata in south central canada peripheral to the quebec embayment form a regional carbonate platform succession within the taconian foreland basin the upper and lower group boundaries record geodynamically controlled changes in regional subsidence whereas a higher order allocyclic stratigraphy traced south along the foreland interior of the eastern united states may identify shorter term eustatic controls a tectonomagmatic event extending across the foreland basin is recorded a few million years prior to the regional collapse of the foreland platform in the quebec embayment within the lower c spiniferus graptolite zone platform margin retreat 50 km in southern quebec is contemporaneous with a shale rich limestone succession that thins 30 10 m westward over 300 km into the ottawa embayment eastern ontario west of the appalachian structural front this stratigraphic record coincides with catastrophic volcanism within the once distant volcanic arc terranes as recorded by a bentonite traced geophysically from the platform margin to the michigan basin core from the ottawa embayment demonstrates western directed transport of lithic bearing ash the lithic material representing reworked deep water sedimentary and or volcaniclastic sediment was entrained by eruption of calc alkaline felsic to basaltic andesitic and trachyandesitic magmatic sources the above geological history documents a short period of diminishing influence of subsidence moving into the platform interior an event that enhanced briefly cross platform oceanographic circulation as recorded by elevated shale abundance and change in macrofaunal assemblages short lived differential subsidence of the continental crust in this region in response to distal tectonism may have been predicated by inherited weakness of a shallowly buried intracratonic 400km precambrian fault system manifest today by the ottawa bonnechere graben the resulting thin 10 to 30 m stratigraphic record of the tectonomagmatic event is of similar thickness to high order allostratigraphic patterns within the taconic foreland interior of the eastern united states because there is a heterogeneous distribution of precambrian fault systems underlying the taconian foreland interior of eastern laurentia differential structural response of the foreland interior can be anticipated the apparent regional allostratigraphy may contain subtle facies differences along the strike of the foreland basin that reflect this tectonic component

trace elements and their isotopes in bones and teeth diet environments diagenesis and dating of archeological and paleontological samples fossil biogenic apatites display trace element te compositions that can record environmental and biological signals give insights into past water compositions or be used for dating paleontological and archeological bones and teeth processes of te incorporation into apatites of skeletal phosphatic tissues are described ranging from those active in living organisms to those active during diagenesis abiotic incorporation mechanisms have been modeled theoretically and experimentally and include crystallographic controls on te partitioning coefficients inorganic surface adsorption and adsorption mediated through chelation and diffusion adsorption processes each leading to specific fractionation patterns predictions from models and experiments have been tested against te concentration and isotopic composition data on remains of contemporary wild or raised animals and on fossils of various ages and environments in living organisms tes incorporated in apatite are separated in two categories non essential elements whose concentration is compared to that of an essential element with similar behavior e g sr ca to reconstruct trophic chains and essential elements whose isotopic ratios are used to trace metabolic activity diet etc in fossils elements are incorporated during diagenesis such as rare earth elements rees and trace diagenetic processes ranging from very early quantitative adsorption likely mediated by chelators protracted diagenesis through inorganic adsorption and fractionation through diffusion adsorption to low grade metamorphism associated with intense redistribution under crystal chemical control these different steps are also identified as steps of radionuclide incorporation only samples where the earliest steps can be deciphered are useful for determining stratigraphic and archeological ages other samples will date late diagenetic events that have obliterated the paleoenvironmental signals but may be of geological significance e g tectonic events

f content variation in mammoth ivory from aurignacian contexts preservation alteration and implications for ivory procurement strategies abstract this article presents the results of two series of micro pixe pige analysis on mammoth ivory samples from four aurignacian sites in france abri castanet grotte d isturitz and germany hohle fels vogelherd specifically we report variation in ivory preservation as indicated by fluorine f content and ratios of mgo cao from aurignacian horizons known to contain ivory industries though all samples derive from respectively homogenous sedimentary contexts results show very different pattern of f content variation among sites f uptake in ivory is a more complex process than that observed for bone and the structural morphological reasons for this are explained high resolution data on the archaeological context of the samples from abri castanet also allows for examination of the effects of horizontal and vertical distribution on f content and the sorting of f content data by sedimentary unit a definitive model for fluorine uptake during ivory diagenesis will require further investigation but a close examination of the current data provides novel insight into processes of taphonomy and diagenesis in this exceptional and highly valued raw material as well as further evidence to support regionally distinct strategies of ivory procurement in the early aurignacian in combination with additional lines of faunal and archaeological evidence it is demonstrated that ivory procurement in the swabian jura focused on fresh local sources of ivory while procurement strategies in northern aquitaine focused on ivory collection from natural deposits of varying age

micro pixe pige analysis of palaeolithic mammoth ivory potential chemical markers of provenance and relative dating abstract micro proton induced x ray and gamma ray emission micro pixe pige provide non destructive methods for the evaluation of the major minor and trace element compositions of archaeological material the current study applies micro pixe pige analysis to mammoth ivory artefacts from four palaeolithic sites abri castanet vogelherd cave grottes de la verpilliere i and ii in france and germany in order to assess the effectiveness of this approach to material older than 30 000 y bp it has thus far not been established whether such methods of analysis can yield results of scientific and archaeological interest on ivory material that has undergone such extended periods of diagenesis this approach evaluated preservation state in terms of mean elemental concentrations mg vs ca and a comparative assessment of f content as an indication of relative burial time the results also indicate that analysis of trace elements sr zn br can provide chemical markers of archaeological provenance the results of this study are compared to data in the existing database established by the same methods of analysis on ivory objects from several different time periods and archaeological sources the implications of these results for the study of archaeological ivories from palaeolithic contexts are discussed

bioapatite 87sr 86sr of the last woolly mammoths implications for the isolation of wrangel island the movements of terminal pleistocene and holocene mammoths on wrangel island off northeastern siberia were investigated using the isotopic composition of sr in skeletal remains a significant shift toward more radiogenic 87 sr 86 sr ratios from 0 71218 0 00103 to 0 71491 0 00138 in bioapatite marks the beginning of the holocene the higher sr isotope values in mid holocene mammoth remains are interpreted as an influence of radiogenic sr derived from the neoproterozoic rocks in the central part of wrangel island the shift implies a change in the ranging and feeding areas of the animals ultimately reflecting the inundation of the mainland connection and isolation of the population the shift indicates also that the late pleistocene animals were not permanent occupants in the territory that makes up present day wrangel island

the double mer formation and the lake melville rift system eastern labrador the double mer formation is a sequence of redbed arkosic sandstone conglomerate siltstone and shale in the grenville province of eastern labrador the formation is closely associated with a rift system extending inland for at least 300 km from the labrador coast substantial thicknesses of strata of double mer formation are confined to two basins the lake melville graben and the double mer half graben strata correlated with the double mer formation are found elsewhere in southeast labrador one isolated outcrop occurs within the sandwich bay graben a separate smaller basin 100 km to the southeast that trends parallel to the lake melville graben the only definite age constraint on the double mer formation is that it postdates grenvillian deformation previously the formation was assigned a latest precambrian to early cambrian age based on lithological similarity with the lower cambrian bradore formation of the southeast coast of labrador on the basis of a structural model proposed here that sugges

diagenesis in prehistoric bone problems and solutions abstract post depositional chemical alteration or diagenesis in prehistoric human bone is the major problem in the use of trace element analyses for dietary reconstruction following a review of recent studies of diagenesis we discuss means for evaluating post depositional chemical change in bone and for removing such contaminants three different procedures are described which reflect current efforts to evaluate and reduce the effects of diagenesis these include 1 mechanical cleaning 2 chemical cleaning through acid washing and 3 washing with a reducing agent these procedures usually remove major contaminants leaving significant potential of trace element analyses for the investigation of past diet

sr isotope evidence for population movement within the hebridean norse community of nw scotland the excavation at cnip isle of lewis scotland of the largest and only known family cemetery from the early norse period in the hebrides provided a unique opportunity to use sr isotope analysis to examine the origins of people who may have been norwegian vikings sr isotope analysis permits direct investigation of a person s place of origin rather than indirectly through acquired cultural and artefactual affiliations sr isotope data suggest that the norse group at cnip was of mixed origins the majority were consistent with indigenous origins but two individuals of middle age and different sex were immigrants they were however not from norway but were raised separately most probably on tertiary volcanic rocks e g the inner hebrides or ne ireland or for the female on marine carbonate rocks

crustal structures of grenville makkovik and southern nain provinces along the lithoprobe ecsoot transect regional seismic refraction and gravity models and their tectonic implications crustal structures of the eastern grenville makkovik and southern nain provinces are determined using seismic reflection refraction and gravity data along the lithoprobe eastern canadian shield onshore offshore transect ecsoot within the grenville province the velocity model contains a 5 km thick upper crust and a variable thickness middle to lower crust the total crustal thickness varies from 25 to 43 km with the thickest crust in the south and thinnest crust in the north a high velocity lower crustal wedge is coincident with a strong band of northward dipping reflectors the two dimensional velocity structure is compatible with modelling of a 60 mgal gravity high over the hawke river terrane in the makkovik province the thickness of upper crustal velocities increases to 17 km the velocity decrease in the upper to middle crust from the grenville province to the makkovik province is similar to that of refraction models across the grenville front in ontario and quebec it is possibly related t

early diagenesis of elephant tusk in marine environment three elephant tusks recovered from a 18th century dutch shipwreck in brittany seawaters were analyzed to study early diagenetic changes of ivory in a marine environment micro small angle x ray scattering saxs analysis revealed sub microscopic structural modifications of ivory hydroxyapatite particle thickness mineralized collagen fibers organization and orientation chemical compositional changes of the organic fraction nitrogen and carbon loss and of the mineral part magnesium loss carbonate calcium chlorine and strontium uptake were investigated by non invasive micro particle induced x ray emission gamma ray emission rutherford and elastic backscattering spectrometry analysis pixe pige rbs ebs these chemical and structural markers can serve as proxies for the early diagenesis of elephant tusk in marine settings the results show that the macroscopic preservation state of the tusk surface does not reflect its microscopic preservation state a diagenetic sequence is proposed depending on the local environment of each tusk first collagen hydrolysis and ion adsorptions from the marine environment are proposed to occur second a tusk buried in the sand was protected from ca enrichment of the surface and the formation of a flaky white concretion whereas tusks out of the sand were subjected to these latter phenomena as well as sea urchin attacks third ion leaching and uptake increased crystallinity of the hydroxyapatite crystals and the modifications of the mineralized collagen fiber network are assumed to happen for all three tusks with different level of completion

red deer antler technology and early modern humans in southeast europe an experimental study abstract in technological approaches to prehistoric industries there is currently a renewed interest in the transformation of osseous materials this approach requires the construction of a technical reference base of manufacturing stigmata as well as of the procedures and methods used to produce tool blanks one of the better known processes for the production of blanks in the upper palaeolithic is extraction by a double longitudinal groove observed only in the gravettian aurignacian artefacts indicate that during this period blanks were obtained through a procedure of longitudinal fracturing splitting or diffuse percussion fracturing the manner of implementing these procedures is however still poorly known in order to better characterise this stage in the manufacturing of blanks for antler points we conducted an experimental study based on a thorough analysis of the spanish archaeological materials we tested the procedure of fracturing by indirect percussion on deer antler the results provide new criteria for the identification of blanks and their manufacturing processes they also emphasize the possibility of predetermining the size of the blank and consequently the size of future projectile point

measurement of vertical profiles of snow specific surface area with a 1 cm resolution using infrared reflectance instrument description and validation the specific surface area ssa defined as the surface area of ice per unit mass is an important variable characterizing the complex microstructure of snow its application range covers the physical evolution of snow metamorphism photochemistry and optical and microwave remote sensing this paper presents a new device posssum profiler of snow specific surface area using swir reflectance measurement designed to allow the rapid acquisition of ssa profiles down to 20 m depth and with an effective vertical resolution of 10 20 mm posssum is based on the infrared ir reflectance technique a laser diode operating at 1310 nm illuminates the snow at nadir incidence angle along the face of a drilled hole the reflected radiance is measured at three zenith angles 20 40 and 60 each for two azimuth angles 0 and 180 a second laser operating at a shorter wavelength 635 nm which is almost insensitive to ssa allows the distance to the snow face to be estimated the reflected ir radiance and the distance are combined to estimate bidirectional reflectances these reflectances are converted into hemispherical reflectances and in turn into ssa using a theoretical formulation based on an asymptotic solution of the radiative transfer equation the evaluation and validation of posssum s ssa measurements took place in spring 2009 in the french alps the new method was compared with the methane adsorption technique and dufisss another well validated instrument based on the ir technique the overall measurement error is in the range 10 15

crustal structure of the grenville province in southeastern labrador from refraction seismic data evidence for a high velocity lower crustal wedge the crustal structure of the eastern grenville and makkovik provinces was determined using two onshore offshore refraction seismic lines of the lithoprobe eastern canadian shield onshore offshore transect ecsoot a gravity high in the hawke river terrane correlates with increased p wave velocities in the upper 30 km of the crust 6 2 6 7 km s in the upper and middle crust and 6 9 7 1 km s below which we interpret as structure inherited from the labradorian orogen velocities in the adjacent groswater bay terrane are 6 0 6 55 km s in the upper and middle crust and 6 6 6 95 km s in the lower crust the entire grenville crust is underlain by a 15 20 km thick high velocity lower crustal hvlc wedge consisting of an upper layer 7 1 7 4 km s and a lower layer 7 6 7 8 km s the hvlc wedge is interpreted as an underplated layer formed during iapetan rifting this interpretation is based on the correlation with the 615 ma long range dykes onshore and the eastward termination of the wedge at the cartwright

measurements and relationships of diagenetic alteration of bone from three archaeological sites four diagenetic parameters have been chosen to represent the state of diagenesis of bone buried on archaeological sites they are histological preservation protein content crystallinity and porosity how these parameters are measured is described and results from populations of bones from three different sites are presented the results show the extent and variation in the degree of change both within a site and between sites in particular the correlations between diagenetic parameters are examined which give clues about the processes which cause alteration the value of porosity determinations both at the intercrystalline level and at coarser levels in revealing the degree of diagenetic change in bone and in underlying the dynamics of the interaction between buried bone and the surrounding water is stressed the data also indicate but are too restricted to prove the following microbiological attack is generally complete within less than 500 years substantial levels of protein may remain in bone after maximal micromorphological alteration loss of protein appears to be independent of other diagenetic change the correlated lose of microporosity with increase of crystallinity suggests these changes may arise from the dissolution perhaps with subsequent recrystallization of the smallest hydroxyapatite crystallites

the early cambrian bradore formation of southeastern labrador and adjacent parts of quebec architecture and genesis of clastic strata on an early paleozoic wave swept shallow marine shelf abstract strata of the bradore formation have been interpreted in terms of a marine transgression developed at the onset of spreading of iapetus ocean with a basal member of fluvial origin a middle member of lagoonal origin and an upper member of tidal channel origin in labrador the formation rests directly on a low relief surface developed on metamorphic rocks of the grenville orogen with no well developed paleosoils re examination of the architecture of pebbly sandstones in the basal blanc sablon member indicate that these formed on an open storm influenced wave swept shelf as part of a low relief sand sheet with evidence of multiple accretionary events structure in sandstones in the middle crow head member is largely obscured by a high density of skolithos linearis domichnia abundance of hummocky cross stratification indicates deepening with a transition to an open storm influenced shallow shelf large scale cross stratification in the glauconite bearing upper l anse au clair member reflects shoaling with a return to deposition of medium scale marine sandwave complexes with no clear evidence of any tidal signature strata of the bradore formation were at least partly lithified prior to deposition of reefal and platformal carbonates in the overlying forteau formation paleocurrent indicators in the upper and lower members suggests that during the initial drift phase of iapetus this segment st lawrence promontory of the laurentian margin was swept by both geostrophic and storm influenced currents largely oriented parallel to the paleocoastline

the influence of meltwater on the labrador current in heinrich event 1 and the younger dryas abstract the labrador current transports freshwater from the arctic regions to the northern atlantic and the freshwater flux can influence the meridional overturning circulation the response of the labrador current to meltwater processes is unclear during the deglaciation of the ice sheets around the northwest atlantic this study utilized cores from flemish pass to monitor variations in the strength of the labrador current by using the sortable silt proxy the carbonate content the amount of ice rafted detritus and xrf chemical data were measured to identify the main meltwater events during the last deglaciation this study observed a clear enhancement of the flow strength of the labrador current in heinrich event 1 and the younger dryas with the greatest flow strength during the younger dryas event the onset of the current enhancement was dated at ca 13 cal ka bp which preceded the enhanced ice rafted deposition in hudson strait by about one thousand years the current enhancement in flemish pass during the younger dryas event corresponds to the freshening of the surface water thus meltwater preceding significant iceberg supply has an important effect on the labrador current in heinrich events on the laurentide ice sheet margin

measuring specific surface area of snow by near infrared photography the specific surface area ssa is considered an essential microstructural parameter for the characterization of snow photography in the near infrared nir spectrum is sensitive to the ssa we calculated the snow reflectance from calibrated nir images of snow pit walls and measured the ssa of samples obtained at the same locations this new method is used to map the snow stratigraphy the correlation between reflectance and ssa was found to be 90 calibrated nir photography allows quantitative determination of ssa and its spatial variation in a snow profile in two dimensions within an uncertainty of 15 in an image covering 0 5 1 0 m 2 even layers of 1 mm thickness can be documented and measured spatial maps of ssa are an important tool in initializing and validating physical and chemical models of the snowpack

why do crystallinity values fail to predict the extent of diagenetic alteration of bone mineral spectroscopic indicators of bone crystallinity such as the infrared splitting factor irsf are commonly used to determine the general state of preservation of ancient bone in principle such indices might be expected to act as a proxy for alteration of bone mineral and thus could be used to screen bones or portions of bones for likely preservation of in vivo biogenic trace element and stable isotope signals we tested the relationship between irsf and bone mineral composition in two suites of well characterised recent and pleistocene bones initially crystallinity change and trace element uptake are correlated apparently both controlled by decomposition of the organic phase and exposure of bone crystal surfaces this relationship breaks down in older bones where authigenic phosphate growth and mineral pore water interactions are no longer rate limited by the breakdown of collagen and exposure of crystal surfaces in these conditions the extent of chemical alteration of bone will be controlled by site specific conditions and thus while ftir spectra of bone provide a broad indication of organic content and apatite recrystallisation they are not reliable proxies for the degree of diagenetic alteration in terms of biogenic geochemical signals

paleomagnetism of pre grenvillian mafic rocks from the northeast grenville province labrador implications for the grenville track a paleomagnetic study of mafic plutonic rocks in the northeast grenville province found five magnetizations interpreted as grenvillian and later overprints components a b and c with the highest unblocking temperatures and distinct regional distributions have paleopoles that appear to lie on the grenville track component c with pole at 348 e 11 s p m 2 4 and mostly distributed in lower grade mafic rocks in the groswater bay terrane near the grenville front is interpreted as a post ca 970 ma grenville overprint predating components a and b the latter components nearly coextensive in distribution in the groswater bay and sandwich bay regions farther south have respective poles at 326 e 02 n n 9 sites p m 8 11 and 348 e 13 n n 13 sites p m 6 8 component b could be interpreted either as a grenville overprint or more likely as a later overprint of late neoproterozoic 615 ma to cambrian age due to rifting in the lake melville region if so many other so

bone diagenesis in arid environments an intra skeletal approach bone trace element content and isotopic composition are closely related to human nutrition the investigation of archaeological bone geochemistry can help us to better understand the relationship between past populations and their environment alongside cultural practices as inferred from dietary reconstruction however dietary in formation may be altered post mortem by diagenetic processes in soil in this study bone mineralogy ca p sec ondary minerals organic matter content and bone apatite crystallinity histology element content mg na f sr ba mn fe la ce and u and stable isotope composition 13cand 18o carbonate were investigated at the intra individual scale in order to understand the effects of diagenesis on skeletons buried in different saharo sahelian environments between 10 to 18 bone samples were taken from 4 neolithic skeletons excavated in the mauritanian dhar oualata and nema and in the daounas mali additionally the enamel of two third molar teeth was also analysed from each skeleton for comparison with bone the results show that the four skeletons buried in the same desert climate area all exhibited different degrees of diageneticmodification relatedto localtaphonomic conditions highly drainedand periodically flooded environments generated substantial bone bacterial damage low to moderate apatite crystallinity and secondary minerals in bone pores bone trace element content and isotopic composition were more diagenetically affected than in bones from skeletons buried in a drier environment which display little bioerosion high apatite crystallinity and the absence or late precipitation of secondary minerals in their bone pores intra skeletal variability of the geochemical composition and the comparison of geochemical data from bones and teeth enables the approximation of ante mortem bone trace element and stable isotope compositions using the best preserved bones from each skeleton

texture and strength changes of buried surface hoar layers with implications for dry snow slab avalanche release buried layers of surface hoar are the failure plane for many slab avalanches including fatal human triggered avalanches in various mountain regions these layers may persist as weak layers in the snow cover for weeks or months it is therefore essential for operational avalanche forecasters to monitor the evolution of persistent weak layers such as buried surface hoar traditional grain shape observations of isolated grains with a magnifier and crystal screen do not show bonding that is decisive for strength in this study we used in situ microphotography and observations of texture to complement strength measurements from shear frame tests buried layers of surface hoar consist of crystals most of which extend from the layer below to the layer above and may exhibit a columnar or truss like structure observations and measurements show that texture and crystal size change little over periods of up to several months during which the snowpack remains dry under these conditions layer thickness decreases while density and strength increase based on field measurements we argue that the increase in strength is primarily due to penetration of the surface hoar crystals into the adjacent layers especially at the bottom of the buried surface hoar layer where bonding is critical the weak bonding at the bottom implies that shear failure occurs at the lower interface rather than within the weak layer on slopes we find that surface hoar crystals that were initially surface normal are tilted downslope faster than predicted by published shear strain rates for settled snow indicating that shear strain is concentrated in these layers the characteristic texture of buried surface hoar columnar or truss like permits collapsing at the time of fracture the gravitational energy released by the displacement of the slab may contribute to the extensive fracture propagation associated with buried surface hoar layers

strontium isotope ratios in fossil teeth from south africa assessing laser ablation mc icp ms analysis and the extent of diagenesis abstract this study tests the precision and accuracy of laser ablation multi collector inductively coupled plasma mass spectrometry la mc icp ms for measuring strontium isotope ratios 87 sr 86 sr in fossil teeth from swartkrans and sterkfontein in south africa and explores the extent of diagenesis in these specimens compared to solution mc icp ms or thermal ionization mass spectrometry tims methods la mc icp ms can be faster and less expensive but has lower precision and accuracy we found that 87 sr 86 sr ratios in fossil rodent teeth measured by la mc icp ms were offset from solution values by a mean of 0 0005 0 0010 2 because of the very wide spread of biologically available 87 sr 86 sr ratios 0 710 to 0 790 in the region la mc icp ms is more than sufficient for assessing the geographic origins of the fossil rodents the concentration of strontium in modern and fossil enamel from the area is statistically indistinguishable as is the range of 87 sr 86 sr ratios in modern rodents and fossil rodents from swartkrans thus there is little evidence of diagenetic sr in the fossil enamel in contrast the fossil dentine may contain up to 50 diagenetic strontium although many dentine 87 sr 86 sr ratios are still far removed from the background cave value of 0 729 we propose that la mc icp ms will also be of use for investigating the geographic origins of other non rodent fossil teeth from the sterkfontein and swartkrans collections and may prove of similar utility at other suitable sites

as a dietary indicator in modern and archaeological bone strontium isotope ratios 87sr86sr in human and animal bone are inherited via foodstuffs from rocks in the areas in which an individual lived if such an area includes more than one rock type with differing 87sr86sr or is coastal region with terrestrial 87sr86sr different from that of the sea then bone strontium isotope ratio measurements provide a measure of the relative importance of foods from each isotopic zone in the southwestern cape of south africa marine and coastal terrestrial areas covered by marine sands should yield foods with 87sr86sr close to the marine average while the cambrian and pre cambrian shales and sandstones of the hinterland ought to be enriched in 87sr from radioactive decay of 87rb during the considerable time elapsed since they were laid down analyses of modern animal bones show that these patterns do prevail furnishing us with a new means of reconstructing prehistoric diets preliminary measurements on archaeological human material recovered from coastal shell midden sites apparently reflect heavy reliance on coastal foods however these bones have been shown to be contaminated with diagenetic marine strontium from the shells in the middens experiments on faunal specimens show that diagenetic strontium can be removed by repeated washing in acetic acid sodium acetate buffer mineral with 87sr86sr similar to the burial environment dissolves first while subsequent washes remove strontium with different 87sr86sr for two coastal human skeletons however the marine coastal terrestrial nature of the isotopic signature remains further experimental work is required in order to establish the limits of the technique however a combination of the solubility profile method and strontium isotope analysis promises to provide a powerful tool for reconstructing palaeodiets

sr isotopic composition of hydroxyapatite from recent and fossil salmon the record of lifetime migration and diagenesis by comparing the sr isotopic composition of migratory fossil salmon which lived in the ocean but died in continental regions to the well established marine sr isotopic record the age of the continental deposit could be determined with high accuracy this approach to marine continental correlation and dating requires 1 that marine resident salmon bear a marine s7sr 86sr value in their bones or teeth and 2 that the original s7sr 86sr value of fossils is not overprinted by diagenesis the vertebrae of modern hatchery reared salmon exhibit sr isotopic variations indicative of freshwater to marine migration during bone growth modern marine s7sr s6sr values were preserved in growth layers formed later in life marine phase growth layers in the bones and teeth of the late miocene migratory salmon oncorhynchus rastrosus were subjected to stepwise selective leaching to separate biogenic hydroxyapatite from diagenetic calcium carbonate and recrystallized hydroxyapatite although the procedure yielded leachates with sr ca and ca p values characteristic of apatite the leachates had 87sr s6sr values consistently less radiogenic than values for late miocene seawater 0 7087 the fossils were substantially contaminated by sr from the hosting clastic sediments specimens in continental deposits differed in 87sr 86sr value from host sediments by 0 0002 to 0 0200 supporting the conclusion that these salmon were migrants from marine waters however because the original sr isotopic composition of fossil bones and teeth cannot be determined with confidence archaeological paleobiological and stratigraphic applications of this technique may be limited

states of preservation of bones from prehistoric sites in the near east a survey abstract a survey of the states of preservation of organic material in 30 fossil bones from 16 different prehistoric sites in the near east shows that whereas almost all the bones have little or no collagen preserved they do with few exceptions contain non collagenous proteins these macromolecules therefore represent an important reservoir of indigenous fossil bone constituents

zinc isotopes in late pleistocene fossil teeth from a southeast asian cave setting preserve paleodietary information stable carbon and nitrogen isotope ratios of collagen from bone and dentin have frequently been used for dietary reconstruction but this method is limited by protein preservation isotopes of the trace element zinc zn in bioapatite constitute a promising proxy to infer dietary information from extant and extinct vertebrates the 66zn 64zn ratio expressed as 66zn value shows an enrichment of the heavy isotope in mammals along each trophic step however preservation of diet related 66zn values in fossil teeth has not been assessed yet here we analyzed enamel of fossil teeth from the late pleistocene 38 4 13 5 ka mammalian assemblage of the tam hay marklot thm cave in northeastern laos to reconstruct the food web and assess the preservation of original 66zn values distinct enamel 66zn values of the fossil taxa 66zncarnivore

differential diagenesis of strontium in archaeological human dental tissues the investigation of prehistoric human migration from the measurement of sr isotope ratios within preserved tissue is critically dependent on the preservation of biogenic sr a number of recent studies have involved isotope ratio measurements on samples of archaeological tooth and bone but doubt remains as to the extent of diagenesis in various skeletal tissues and the effectiveness of procedures designed to decontaminate them the authors have compared sr abundance and isotope ratios in enamel and dentine from archaeological teeth in order to assess the integrity of the biogenic sr signal preserved within the respective tissues it is concluded that enamel appears in most cases to be a reliable reservoir of biogenic sr but that dentine and by implication bone is not the diagenesis of dentine is highly variable even between burials within a single site for the majority of teeth dentine diagenesis was not simply by addition of soil derived sr but involved substantial sometimes complete turnover of the original biogenic material it is suggested that for most of the samples investigated current decontamination techniques may not have been effective in isolating biogenic sr from dentine similar considerations are likely to apply to archaeological and fossil bone but the possibility arises to use dentine and enamel measurements to assess the effectiveness of decontamination procedures which may then be used for bone

mineralogical and compositional changes in bones exposed on soil surfaces in amboseli national park kenya diagenetic mechanisms and the role of sediment pore fluids abstract bones exposed on tropical savannah grasslands of amboseli national park kenya undergo extensive post mortem alteration within 40 years a combined analytical approach involving tem microscopy trace metal analysis ftir spectroscopy and petrographic analysis has revealed a complex dynamic diagenetic environment operating within exposed bones driven by evaporative transport of soil water from the bone soil interface to the upper exposed surface of the bone this process results in extensive bone soil water interaction and is responsible for increases in the concentrations of trace elements such as ba and la of 100 1000 within 15 years the maximum and mean size of bone crystallites increases with continued exposure this change in mean crystallite length is correlated positively with increases in bone crystallinity which in turn is associated with degradation of the bone protein microbial decomposition is rarely observed in the amboseli bones but where present resulted in severe dissolution reprecipitation of bone mineral many bones showed extensive permineralization of the larger vascular spaces with calcite and barite and to a lesser extent crandallite permineralization of unburied bones may account for 95 reduction in macro micron millimeter scale porosity in the bone within 2 years of death we produce a model for pre burial diagenesis of bone in arid tropical environments that highlights extensive alteration of bone chemistry within 1 40 years post mortem

evaluating the impact of acetic acid chemical pre treatment on old and cremated bone with the perio spot technique and perios endos profiles abstract the impacts of diagenesis on archaeological and palaeontological bone complicate investigations of in vivo chemical and isotopic characteristics such bone is often pre treated in an attempt to remove diagenetic alteration prior to trace element or isotopic analyses although very few standardized approaches exist for evaluating pre treatment effectiveness in this pilot study we characterize the diagenetic alteration and assess the impact of acetic acid chemical pre treatment on the trace element and structural characteristics of four bones from belgium including an early medieval cremated bone from broechem and three representative old bones of different ages ca 40 130 ka from the late pleistocene sedimentary sequence of scladina cave each bone was analyzed before and after acetic acid pre treatment using the perio spot technique and perios endos profiles we measured trace element concentrations with laser ablation inductively coupled plasma mass spectrometry la icp ms and micro x ray fluorescence spectroscopy xrf structural characteristics were investigated with raman spectroscopy and fourier transform infrared spectroscopy ftir our results indicate that chemical pre treatment had little to no significant impact on the trace element content of the early medieval cremated bone had the most impact on the youngest bone from scladina cave and had less impact on the trace element content of two older bones from scladina cave this suggests that the effectiveness of acetic acid chemical pre treatment is greater for bones undergoing early diagenetic processes has minimal impact on highly crystalline cremated bone and may preferentially leach in vivo signatures from bones undergoing later diagenesis the weights of leachates removed from each bone also correspond well with their hypothetical diagenetic states indicating that researchers could potentially assess the diagenetic state of bones by weighing the leachates produced during acetic acid pre treatment therefore our new approach may provide a valuable step toward effectively and consistently differentiating among in and ex vivo trace element signatures and by proxy those of their isotopes in archaeological and palaeontological bone

mobility of bell beaker people revealed by strontium isotope ratios of tooth and bone a study of southern bavarian skeletal remains in order to contribute to the continuing discussion of the mobility of the late neolithic bell beaker people 69 skeletons from southern bavaria were analyzed for the 87sr 86sr isotope ratios in tooth enamel and compact bone whereas sr isotope ratios in the enamel of the first permanent molar match the sr isotopic composition at the place of early childhood the respective value in the adult femoral bone matches the sr isotope ratio characteristic of the place of residence over the last few years prior to death significant differences between 87sr 86sr in these tissues indicate that 17 5 25 of these individuals changed residence during their lifetime the overall direction of the migration according to archaeological finds from the area was toward the southwest a relative surplus of migrating females and two cases of evidence for migration in children argue for the movement of small groups exogamy might explain the higher numbers of immigrating females with regard to current information on migration rates in prehistory the southern bavarian bell beaker people were indeed highly mobile especially since the archaeometric method used in this study is likely to underestimate movement

diagenesis of strontium in fossil bone a reconsideration of nelsonet al 1986 abstract in experiments on marine animal fossils that had been buried in terrestrial sediments nelsonet al 1986 geochimica et cosmochimica acta50 1941 1949 reported that the strontium sr of prehistoric bone had nearly completely exchanged with that of the burial environment and therefore cannot be used for paleodietary reconstruction however sealyet al 1991 journal of archaeological science18 399 416 using a solubility profile procedure reported that it was possible to remove diagenetic sr and obtain biologically meaningful sr nevertheless the nelsonet al study is often cited as evidence that a biological signal is irretrievable here infra red spectrometry xrd spectrometry and elemental analyses were used to compare the effects of the nelsonet al protocol with the solubility profile protocol on the crystal structure and crystallinity of the bone and fossil specimens the results show that the procedures used by nelsonet al which include a preliminary ashing step result in severe recrystallization of apatite both before and during the leaching step which deleteriously affects any attempt to recover biological sr by contrast no observable recrystallization takes place in the solubility profile procedure the results imply that the conclusions reached by nelsonet al are primarily artefacts of the specific methods used in their study rather than due to any inherent mechanism of diagenesis

microbial attack of archaeological bones versus high concentrations of heavy metals in the burial environment a case study of animal bones from a mediaeval copper workshop in paris abstract microbial attack is one of the key processes altering archaeological bone during the early stage of diagenesis some burial conditions seem more prone to prevent microbial attack in archaeological bone it is generally admitted that the presence of certain metals in the burial environment such as copper may have an inhibiting effect on microbial destruction of archaeological bone this study was aimed at evidencing such effects by the investigation of different archaeological animal bones excavated from several activity zones of one french archaeological urban site corresponding to a mediaeval copper alloys workshop in paris at hotel de mongelas the analytical approach combined morphological observations sem structural investigations ft ir xrd and tem and chemical analyses sem edx and pixe pige of archaeological bones at different scales down to the nanoscale it permitted the classification of the bones as a function of their contamination with heavy metals their conservation state and the presence of signs of microbial attack correlations between the observed alteration features and the metallurgical activity on this site as well as the underlying alteration processes are discussed an inhibiting effect of heavy metals on the microbial attack could be deduced from the available though restricted data in agreement with the expectation however the relationship between heavy metal uptake and microbial alteration of bone depends on other diagenetic factors and their progress such as bone collagen content crystallinity of bone mineral soil geochemistry and hydrology significant changes in environmental conditions over time which can especially occur in urban sites can also influence alteration phenomena generally simultaneous alterations induced by heavy metal uptake and microbial attack seem to take place in the very early stage of diagenesis and influence one another in sites with soils highly contaminated in heavy metals

87sr 86sr ratios in modern and fossil food webs of the sterkfontein valley implications for early hominid habitat preference this research addresses the potential contribution of strontium isotopes to the reconstruction of early hominid behavior at the swartkrans site in the sterkfontein valley of gauteng provence formally known as the transvaal south africa we report that while there is considerable variability in the 87sr 86sr of whole soils within a 15 km radius of this site available soil and grassland plant 87sr 86sr is much less variable and generally above 0 730 this value is higher more radiogenic than the 87sr 86sr of plants growing within the greenbelt surrounding the blaaubank stream adjacent to swartkrans and streamwater itself 0 721 the difference between grassland and riparian strontium isotope composition suggests a method for determining habitat utilization by early hominids in this study a geological explanation for a natural difference between blaaubank stream and grassland sr is suggested based on relatively less radiogenic sr having lower 87sr 86sr values in the carbonate component of the local dolomite when compared to other nearby geological formations the explanation was tested initially using a top down approach in which the 87sr 86sr ratios of water soil and plants from the entire blaaubank catchment were measured next a bottom up approach was used to examine swartkrans member i faunal species known to have obtained their sr from well defined habitats the results are that 1 pollution is not the explanation for the relatively low 87sr 86sr ratios of the blaaubank stream 2 swartkrans member i carbonate has a similar 87sr 86sr to that of modern blaaubank water indicating that relationships seen today existed in the pleistocene and 3 pleistocene riparian fauna have relatively low 87sr 86sr ratios when compared to fauna adapted to drier habitats together these results make it possible to interpret the strontium isotope composition of pleistocene early hominids from swartkrans in terms of habitat utilization

crustal evolution in eastern labrador constraints from precise u pb ages abstract new u pb ages for rocks of eastern labrador complement previous u pb dates for the grenville and makkovik provinces and substantiate the following conclusions eastern labrador consists of two distinct crustal blocks that are different in age as well as magmatic metamorphic and structural overprint the northern block includes archaean to lower proterozoic basement rocks 1900 ma and two distinct episodes of rhyolitic volcanism at 1860 and 1807 ma high grade metamorphism deformation and anatexis affected this block between 1860 and 1760 ma ago makkovikian orogeny the southern block comprises the trans labrador batholith and the various terranes of the grenville province in contrast to the northern region the southern block shows no proof for the existence of continental crust older than 1710 ma this suggests that large amounts of juvenile material were added between 1710 and 1630 ma ago as dated by a large series of precise rock ages at least towards its end this crust forming event was associated with high grade metamorphism deformation and anatexis labradorian orogeny the 1710 1630 ma period of activity was followed by three distinct phases of anorogenic plutonism causing the emplacement of pegmatites 1500 ma a widespread suite of cotonitic metagabbros michael gabbro 1426 ma and granitic syenitic bodies 1296 ma during the grenvillian orogeny the region achieved its present structural configuration including the emplacement of granitoid plutons the structurally highest regions the mealy mountains and the hawke river terranes were thrust over the lake melville terrane and part of the groswater bay terrane and they were only marginally affected by grenvillian metamorphism the more deeply buried lake melville and groswater bay terranes however were significantly modified during tectonothermal events at 1030 ma and 980 960 ma respectively