a diffusion adsorption model of uranium uptake by archaeological bone abstract an argument for the possibility of uranium uptake by buried bone taking place through the adsorption of uranyl species on bone mineral is advanced in the light of this a diffusion adsorption model for uranium uptake by buried bone is developed the necessary constants are evaluated from the literature and from laboratory measurements of the partition coefficient between solution and bone mineral the geochemical and hydrological parameters which control uptake are discussed the predictions of the model are shown to be in general accordance with the timescale magnitude and distribution of uranium uptake in archaeological bone using the model specific predictions of the variation of apparent uranium series ages in bone can be made and bone is shown clearly not to conform to the closed system assumption when the model is extended to tooth enamel it is found to be incompatible with the early uptake model used for esr dating but to fall between the early uptake and linear uptake models similarly it suggests that uranium series dates on enamel assuming a closed system are liable to underestimate the true age by at least one third

models of diffusion limited uptake of trace elements in fossils and rates of fossilization abstract many fossils are assumed to take up trace elements by a process of combined diffusion plus adsorption da yet in principle composition profiles can be explained by several different diffusion limited processes including diffusion plus reaction or recrystallization dr and double medium diffusion dmd the da and dmd models are supported by ree and u composition profiles across fossil teeth measured by laser ablation icp ms that show error function like diffusion profiles into enamel from the dentine enamel interface and concentrations in the interior of enamel that are at original biogenic levels or higher published composition and age profiles in some pleistocene bones may be better explained by a dr model all three diffusion models imply linear behavior between age and distance squared vastly simplifying u series dating methods for pleistocene fossils modeled uptake rates for fossil teeth yield a strict minimum bound on durations of about one decade to one century the similarity of diffusion profiles in teeth irrespective of depositional ages ranging from 30 ka to 30 ma implies that uptake occurred quickly with a maximum duration of a few tens of kyr for typical fossil enamel faster uptake is implied for typical fossil bone and dentine disparities in these uptake estimates compared to some archeological bone may reflect sampling and preservation bias for paleontological vs archeological materials

early diagenesis and recrystallization of bone abstract one of the most challenging problems in paleobiology is determining how bone transforms from a living tissue into a fossil the geologic record is replete with vertebrate fossils preserved from a range of depositional environments including wetland systems however thermodynamic models suggest that bone modeled as hydroxylapatite is generally unstable in a range of varying geochemical conditions and should readily dissolve if it does not alter to a more thermodynamically stable phase such as a fluorine enriched apatite here we assess diagenesis of alligator bone from fleshed articulated skeletons buried in wetland soils and from de fleshed bones in experimental mesocosms with and without microbial colonization when microbial colonization of bone was inhibited bioapatite recrystallization to a more stable apatite phase occurred after one month of burial ca fe phosphate phases in bone developed after several months to years due to ion substitutions from the protonation of the hydroxyl ion these rapid changes demonstrate a continuum of structural and bonding transformations to bone that have not been observed previously when bones were directly in contact with sediment and microbial cells rapid bioerosion and compositional alteration occurred after one week but slowed after one month because biofilms reduced exposed surfaces and subsequent bioapatite lattice substitutions microbial contributions are likely essential in forming stable apatite phases during early diagenesis and for enabling bone preservation and fossilization

early diagenesis of bone and tooth apatite in fluvial and marine settings constraints from combined oxygen isotope nitrogen and ree analysis abstract fossil bones and teeth of late pleistocene terrestrial mammals from rhine river gravels rs and the north sea ns that have been exposed to chemically and isotopically distinct diagenetic fluids fresh water versus seawater were investigated to study the effects of early diagenesis on biogenic apatite changes in phosphate oxygen isotopic composition 18opo4 nitrogen content wt n and rare earth element ree concentrations were measured along profiles within bones that have not been completely fossilized and in skeletal tissues bone dentine enamel with different susceptibilities to diagenetic alteration early diagenetic changes of elemental and isotopic compositions of apatite in fossil bone are related to the loss of the stabilizing collagen matrix the ree concentration is negatively correlated with the nitrogen content and therefore the amount of collagen provides a sensitive proxy for early diagenetic alteration ree patterns of rs and ns bones indicate initial fossilization in a fresh water fluid with similar ree compositions bones from both settings have nearly collagen free ree u f and sr enriched altered outer rims while the collagen bearing bone compacta in the central part often display early diagenetic pyrite void fillings however ns bones exposed to holocene seawater have outer rim 18opo4 values that are 1 1 to 2 6 higher compared to the central part of the same bones 18opo4 18 2 0 9 n 19 surprisingly even the collagen rich bone compacta with low ree contents and apatite crystallinity seems altered as ns tooth enamel 18opo4 15 0 0 3 n 4 has about 3 lower 18opo4 values values that are also similar to those of enamel from rs teeth therefore ree concentration n content and apatite crystallinity are in this case only poor proxies for the alteration of 18opo4 values seawater exposure of a few years up to 8 kyr can change the 18opo4 values of the bone apatite by 3 therefore bones fossilized in marine settings must be treated with caution for palaeoclimatic reconstructions however enamel seems to preserve pristine 18opo4 values on this time scale using species specific calibrations for modern mammals a mean 18oh2o value can be reconstructed for late pleistocene mammalian drinking water of around 9 2 0 5 which is similar to that of late pleistocene groundwater from central europe

putative dicynodont coprolites from the upper triassic of poland abstract a significant number more than 100 of brown to dark and silty carbonate or pyrite mineralized in part organic carbon rich spherical or oval shaped structures have been collected from the upper triassic uppermost norian lower rhaetian sediments of the lipie l skie clay pit at lisowice near lubliniec town poland their geological context morphology content geochemistry and association with skeletal remains suggest they are fecal masses of a sizable herbivorous tetrapod the only large herbivore known from the site is a giant 5 meter long dicynodont synapsida anomodontia represented by numerous bones and also by large oval shaped footprints the putative dicynodont coprolites were collected from mudstone and siltstone with numerous organic remains that were deposited in anoxic conditions in addition rees and other trace element concentrations suggest that the burial environment and diagenesis of these coprolites were under anoxic conditions sem and thin section images of the coprolite matrix show numerous nests with pyrite probably bacterial in origin and large amount of mineral particles the putative dicynodont coprolites contain also amorphous dark organic matter poorly preserved palynomorphs small fragments of plant cuticle detailed characteristic of these coprolites reveals possible implications for the ecology and physiology of the source animal species the 13 c values of the gymnosperm cuticle and dark organic matter measured in three coprolites are 23 4 21 2 and 20 3 all average the evidence from these coprolites suggests that dicynodonts processed plant soft elements into very small pieces but wood fragments were found also in a mass accumulation in two coprolites

geochemical taphonomy of the standing rock hadrosaur site exploring links between rare earth elements and cellular and soft tissue preservation abstract the standing rock hadrosaur site srhs in south dakota preserves a mass death assemblage of the hadrosaurine dinosaur edmontosaurus annectens in the upper cretaceous hell creek formation a previous study of srhs bones found many of them to yield microstructures morphologically consistent with vertebrate osteocytes blood vessels and proteinaceous matrix upon demineralization with weak acid to examine the geochemical history of these specimens in detail we herein document the intra bone distribution of rare earth elements ree within nine of these previously examined edmontosaurus limb bones from srhs laser ablation inductively coupled plasma mass spectrometry was used to determine the trace element composition of the specimens which revealed the bones to possess unusually low ree concentrations for bones of mesozoic age consistent and steep declines in light ree concentrations with increasing cortical depth and uniformly low concentrations of middle ree and elements with moderate and low diffusivities through the middle cortex these attributes imply 1 at least partial preservation of early diagenetic trace element signatures 2 that trace element uptake occurred primarily during a single early diagenetic phase and 3 that the duration of trace element diffusion was brief in these bones as we previously reported low permeability of the fine grain host matrix and early diagenetic cementation of portions of the host matrix by precipitation of siderite concretions impeded pore fluid replenishment this partial hindrance of fluid flow was also likely responsible for the minimal trace element uptake observed in the nine srhs specimens further studied herein from a paleontological perspective minimal trace element uptake reflects minimal chemical alteration meaning bones from this site are predicted to be ideal candidates for preservation of original organics according to hypotheses previously advanced by geochemical studies because low ree concentrations reflect limited interaction with groundwaters during diagenesis we propose that late diagenetic overprinting of early diagenetic ree profiles was minimal and that hydrolytic degradation of soft tissues was limited in the burial environment at srhs mitigation of biomolecular decay by hydrolysis would favor ultrastructure stabilization and is therefore advanced as a partial explanation for the preservation of cells and soft tissue microstructures in these fossil bones

bone diagenesis and origin of calcium phosphate nodules from a hominid site in the lukeino formation tugen hills kenya the lukeino formation 6 09 5 68 ma kenya is a fossiliferous fluvio lacustrine sedimentary sequence 100 m thick which yielded the fossil remains of the oldest east african bipedal hominid called orrorin tugenensis at one of the hominid sites aragai centimetric to pluri centimetric indurated calcium phosphate nodules occur in a specific sedimentary layer mineralogical and geochemical analyses coupled with sem optical microscopy and cathodoluminescence observations were performed on four calcium phosphate nodules and one bone showing differential alteration with characteristics locally similar to that of the nodules in order to determine the nature and origin of these nodules a crystallinity index ci and histological index hi were also assigned to these samples to characterize their degree of transformation analyses reveal that all nodules and the studied bone have a similar mineralogical and chemical composition nodules show no internal structure and are composed of a carbonate fluorapatite matrix including feldspars clays and spheres of iron and manganese oxides their high ci indicates significant recrystallization compared to modern bone the altered bone shows infilling of the trabecular cavities characterized by a clay deposit along the walls oxide spheres with a silica center and carbonate fluorapatite baguettes in the highly altered area of the bone a phenomenon of dissolution and dismantlement of bone structures adjacent to an area characterized by the presence of a phosphate matrix is observed the genesis of these calcium phosphate nodules seems to result from an advanced stage of transformation of bones due to a combination of physical chemical and biological bacterial processes the different stages of diagenesis are characterized by the incorporation of components from the sedimentary layer including diatoms and by neoformations of clays and oxides in the bone pores the bone structure is affected by fracturing and dissolution of carbonate hydroxylapatite which reprecipitated in bone cavities under the form of carbonate fluorapatite automorphic crystals then the bone structures and mineral neoformations were affected by a dismantlement phenomenon which increased the dissolution of the bone apatite this resulted in a carbonate fluorapatite matrix in which no trace of the initial bone structure is visible this particular mechanism of genesis of calcium phosphate nodules most probably takes place by action of fluid circulation in a confined environment such as a lake edge or marsh

provenancing of hominid and mammalian fossils from kanjera kenya using edxrf abstract we describe a rapid non destructive energy dispersive x ray fluorescence edxrf technique for provenancing fossil bone and apply it to surface collected fossils from kanjera kenya the locality is best known for its controversial anatomically modern human fossils potentially among the earliest from africa excavations of the 1987 1988 smithsonian expedition provided the in situ fossil sample necessary to provenance the previous finds relative sr y zr u rb rn and th concentrations were used to characterize 301 fossils from six stratigraphic units the sources of the surface fossils important fossils from past kanjera expeditions including the hominid and theropithecus oswaldi samples were analysed and their relative elemental values used to assign them to a reference sample the hominids post date kanjera formation deposition the t oswaldi fossils are largely attributable to the early pleistocene kanjera bed kn 2a secondary deposition of kanjera formation fossils into later strata was noted

rare earth element complexation behavior in circumneutral ph groundwaters assessing the role of carbonate and phosphate ions rare earth element ree concentrations were determined in circumneutral ph 7 ph 9 groundwaters from south central nevada and the mojave desert in eastern california u s a the inorganic speciation of the rees in these water were evaluated primarily to assess the relative importance of carbonate lnhco32 lnco3 and ln co3 2 and phosphate lnh2po42 lnhpo4 ln hpo4 2 and lnpo40 complexes other ree complexes with sulfate hydroxyl chloride and fluoride ions were also assessed as was the significance of the free metal ion species i e ln3 our speciation calculations indicate that ree carbonate complexes dominate and typically account for more than 99 of each ree in solution moreover carbonato complexes lnco3 were predicted to be the dominant species for the light rees and dicarbonato complexes ln co3 2 were predicted to increase in importance with increasing atomic number all other complexes were predicted to be negligible furthermore the combined percentage of all ree phosphate complexes never accounted for more than 0 1 of the dissolved rees and generally much less than 0 1 phosphate complexes can not compete with carbonate complexes in these groundwaters because of the low po43 concentrations 0 3 1 58 mol kg the much lower concentrations of the free phosphate ion i e po43 f 10 9 10 6 mol kg due to ion pair formation with ca2 and mg2 and the much higher free carbonate ion concentrations co32 f 0 32 87 mol kg

nd and sr isotope compositions in modern and fossil bones proxies for vertebrate provenance and taphonomy abstract rare earth elements ree while not essential for the physiologic functions of animals are ingested and incorporated in ppb concentrations in bones and teeth nd isotope compositions of modern bones of animals from isotopically distinct habitats demonstrate that the 143 nd 144 nd of the apatite can be used as a fingerprint for bedrock geology or ambient water mass this potentially allows the provenance and migration of extant vertebrates to be traced similar to the use of sr isotopes although ree may be enriched by up to 5 orders of magnitude during diagenesis and recrystallization of bone apatite in vivo 143 nd 144 nd may be preserved in the inner cortex of fossil bones or enamel however tracking the provenance of ancient or extinct vertebrates is possible only for well preserved archeological and paleontological skeletal remains with in vivo like nd contents at the ppb level intra bone and tooth ree analysis can be used to screen for appropriate areas large intra bone nd concentration gradients of 10 1 10 3 are often measured nd concentrations in the inner bone cortex increase over timescales of millions of years while bone rims may be enriched over millenial timescales nevertheless e nd values are often similar within one e nd unit within a single bone larger intra bone differences in specimens may either reflect a partial preservation of in vivo values or changing e nd values of the diagenetic fluid during fossilization however most fossil specimens and the outer rims of bones will record taphonomic 143 nd 144 nd incorporated post mortem during diagenesis unlike ree patterns 143 nd 144 nd are not biased by fractionation processes during ree uptake into the apatite crystal lattice hence the e nd value is an important tracer for taphonomy and reworking bones and teeth from autochthonous fossil assemblages have small variations of 1 e nd unit only in contrast fossil bones and teeth from over 20 different marine and terrestrial fossil sites have a total range of e nd values from 13 0 to 4 9 n 80 often matching the composition of the embedding sediment this implies that the surrounding sediment is the source of nd in the fossil bones and that the specimens of this study seem not to have been reworked differences in e nd values between skeletal remains and embedding sediment may either indicate reworking of fossils and or a ree uptake from a diagenetic fluid with non sediment derived e nd values the latter often applies to fossil shark teeth which may preserve paleo seawater values complementary to e nd values 87 sr 86 sr can help to further constrain the fossil provenance and reworking

heterogeneous rare earth element ree patterns and concentrations in a fossil bone implications for the use of ree in vertebrate taphonomy and fossilization history abstract a bone fragment cgdq 3 of falcarius utahensis a therizinosaur from the early cretaceous cedar mountain formation utah contained within a carbonate nodule was analyzed by laser ablation inductively coupled plasma mass spectrometry la icp ms in order to investigate ree variability within a thin walled phalanx previous studies have found depth related ree pattern variations however in cgdq 3 variation occurs along the circumference of the bone nasc normalized ree patterns and concentrations vary between two apparent end members a light ree enriched lree pattern similar to solution icp ms analysis of this bone characterizes approximately two thirds of the bone fragment total ree concentrations are high and do not vary significantly from the periosteal surface to the medullar surface conversely the remaining one third of the bone has ree patterns that are mree depleted and low in total ree concentrations ree concentrations in this part of the bone do not vary significantly from the periosteal to the medullar surface a positive ce anomaly is found throughout the entire bone and is greatest within the lree enriched portion of the bone this in combination with the lree enrichment suggests that the bone fossilized under reducing conditions the distance between the lree enriched and mree depleted regions is less than 1 mm isotopic and petrographic analyses of the bone and surrounding carbonate matrix suggest the ree patterns in the bone were the result of partial fossilization incomplete filling of micro pore spaces around bone crystallites in an environment with changing redox conditions the lower mree depleted part of the bone fossilized contemporaneously with a pendant cement that formed on the underside of the bone in the vadose zone formation of the pendant cement restricted water flow through the bone isolating the lower portion which incorporated a mree depleted pattern the upper part of the bone lree enriched side fossilized under more reducing conditions than the lower part this resulted in reductive dissolution of minerals such as hydrous ferric oxides and manganese oxides which were lree enriched with positive ce anomalies these ree were then incorporated into the upper part of the bone this likely occurred after the bone entered the saturated zone below the water table the thinness of the bone and presence of a pendant cement helped facilitate partial fossilization of the bone preserving the ree signature of an earlier fluid as demonstrated by this case study differences in ree patterns within a fossil may record changes in geochemical conditions during fossilization particularly when bones are encased in a material that reduces fluid permeability such as micritic vadose calcite analysis of such bones may offer the opportunity to decipher complex fluid histories that occur during fossilization la icp ms should be utilized to confirm solution icp ms analysis if it yields high ree variability prior to an interpretation of reworking or time averaging

physical properties geochemistry and diagenesis of xenarthran teeth prospects for interpreting the paleoecology of extinct species abstract xenarthrans also called edentates include modern armadillos sloths and numerous extinct clades e g glyptodonts and ground sloths that lack enamel on their teeth in contrast to mammals with tooth enamel which oftentimes preserves geochemical proxy data paleoecological interpretations of xenarthrans based on geochemical analyses e g stable isotopes have been limited xenarthrans have evolved a distinctive outer dentine layer that seems to be the functional analog of enamel here we evaluate the physical and chemical properties of xenarthran outer dentine to understand its potential use for investigating geochemical proxies the mean hardness h of xenarthran outer dentine 3 8 is significantly less than that of enamel 5 7 and there is no difference in h between the two main groups i e armadillos cingulates and pilosans sloths although the mean h does not change significantly during diagenesis its range increases indicating the replacement of secondary minerals e g carbonate representing the lower range within the original hydroxylapatite mineral lattice results of ft ir analyses indicate that xenarthran outer dentine has a high degree of organics and h2o similar to normal dentine and its crystallinity index and carbonate content are affected in varying degrees during diagenesis thus although xenarthran outer dentine functions like enamel it retains compositional similarities to dentine the uptake of rare earth elements ree was analyzed from three late neogene localities in florida as a proxy for understanding diagenesis in xenarthrans as compared to other mammals relative to modern specimens the fossils have about two orders of magnitude higher concentrations of ree uptake rates vary significantly among different dental tissues i e bone dentine both inner and outer enamel ree concentrations of fossil vertebrate specimens vary significantly between different localities the ree index ratio of outer dentine bone or enamel bone for a given specimen is proposed here to evaluate relative diagenesis in xenarthrans and other mammals respectively other non xenarthran mammals tend to have a lower ree index interpreted to represent less diagenesis nevertheless many xenarthrans likewise have a low ree index relative to other mammals at the same locality indicating a similar degree of diagenesis while the ree index will likely be a reliable indicator of relative diagenesis in xenarthrans the outer dentine provides challenges to the ultimate goal of interpreting proxy geochemical e g stable isotope data from these extinct mammals

chemical evolution of rare earth elements fractionation between colloidal and solution phases of filtered river water abstract within the dissolved fraction of connecticut river water there is large scale fractionation of rare earth elements between colloidal and solution phases colloidal particles carry a large part of the dissolved ree pool filtration through filters with progressively smaller pore size 0 45 0 22 and 0 025 m results in filtrates with lower absolute concentrations of ree and more fractionated compositions with decreasing pore size the filtrates have shale normalized abundances which become systematically more depleted in the lree relative to the hree hence both the solution and colloidal phases are significantly fractionated with respect to the dissolved fraction these conclusions are consistent with previous studies of ree in rivers estuaries and soils and with surface solution speciation models colloids play an important role in the aquatic geochemistry of rare earth elements they are responsible for the fractionation of ree during the estuarine removal of ree the removal of suspended and colloidal particles from river water leaves the solution phase of river water with compositions of ree as evolved as those of surface seawater hence the evolution of the composition of ree in river water and seawater is significantly influenced by colloid formation during chemical weathering on the continents

chemistry microstructure petrology and diagenetic model of jurassic dinosaur bones dinosaur national monument utah abstract the fossil bone mineral in dinosaurs from the morrison formation is well crystallized stoichiometric francolite the closely packed subparallel francolite crystals have equidimensional cross sections mostly 10 40 nm wide in contrast crystallites in unaltered mammal bone tissue are poorly crystallized nonstoichiometric carbonate hydroxyapatite a few nanometers thick and plate rod or needle shaped the diagenetic francolite crystals are elongated in the c axis direction as are bone tissue crystallites along permeable cracks francolite crystals grew to 250 nm wide compared to unaltered crystallites in mammal bones the francolite has higher concentrations of ba ce cr f la mn ni pb rb sr th u v and y and perhaps zr na and mg are lower in concentration diagene ic francolite grew from groundwater enriched in ions from silicic ashes in the brushy basin member and from dissolution of bone tissue crystallites after burial francolite grew on crystallite seeds filling the space formerly occupied by collagen perhaps half the tissue volume and dissolved crystallites the micron scale structures such as haversian canals and laminae are preserved because the diagenetic francolite retains the orientations of the seeds the laminae 1 10 m thick commonly preserve an orthogonal plywood structure the diagenetic growth of francolite during this type of bone fossilization implies that oxygen isotopic ratios measured in dinosaur bones even those that appear fresh and unaltered may dominantly reflect groundwater temperature rather than dinosaur body temperature trace element concentrations in the francolite may reflect groundwater composition rather than dinosaur diet pore filling cements precipitated in the sands and bones at shallow burial depths as evidenced by the 35 52 minus cement porosities of the sandstones and numerous uncompacted oversize pores filled by cements gypsum and calcite were precipitated from shallow alkaline groundwater as the groundwater became increasingly dominated by ions from silicic ash argentite chalcopyrite native gold native silver tiemannite and uraninite replaced areas of bone a few microns to tens of microns in size along cracks a thin chlorite crust commonly mantled francolite crystals along bone cracks and lined openings in bones and sandstones pervasive precipitation of a chalcedony crust followed with pseudomorphs of chalcedony after gypsum in larger cancellous openings the remaining space was fi led by the various forms of silica the bones are brown due to goethite filled cracks that cut pore filling minerals

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

palaeoenvironments of vertebrates on the southern shore of tethys the nonmarine early cretaceous of tunisia abstract through the late jurassic and early cretaceous the southern shore of the tethys ocean migrated north and south over short distances these vicissitudes are documented in the continental intercalaire a long series of mainly non marine sediments deposited across north africa a combined taxonomic physical and chemical taphonomic study provides independent lines of evidence for reconstruction of palaeoenvironments within this marginal marine setting the douiret chenini and oum ed diab formations from the tataouine basin of southern tunisia span the later part of the early cretaceous microvertebrates from four sites in these formations show different modes of physical abrasion time averaging and mixing based on a taphonomic analysis using a combination of physical and chemical methods the taxonomic composition of each assemblage and trends in rare earth element ree compositions of bones from each locality were used as independent lines of evidence to indicate differences in early depositional environments the jebel boulouha assemblage douiret formation is interpreted as a terrestrial carbonate rich environment with relatively little mixing the touil el mra assemblage oum ed diab formation suggests a marginal marine environment with some mixing of previously interred bones the oued el khil assemblage chenini formation and the oum ed diab assemblage oum ed diab formation are more equivocal suggesting mixed freshwater and marine influences interpreting salinity in marginal marine settings is difficult and best attempted from multiple independent lines of evidence we suggest that ree geochemistry can contribute to palaeoenvironmental reconstruction when used in combination with other independent physical palaeontological and or geochemical methods

rare earth element concentrations and speciation in organic rich blackwaters of the great dismal swamp virginia usa concentrations of rare earth elements ree major inorganic solutes and dissolved organic carbon doc were measured in waters from the great dismal swamp in southeastern virginia including lake drummond ph 4 3 and its principal surface inflows and outflow concentrations of ree are high in the lake average nd 8 nmol kg and the acidic doc rich inflow and out flow waters i e nd 12 5 nmol kg in jericho washington ditch and 8 nmol kg in feeder ditch respectively the slightly acidic ph 6 6 4 inflow waters from west of the suffolk scarp that comprise the chief source of surface water flow into lake drummond exhibit lower ree concentrations nd 3 4 7 nmol kg great dismal swamp waters are all enriched in the middle rees compared to the light and heavy rees lree and hree when normalized to upper continental crustal ucc values rare earths are positively correlated to doc concentrations in great dismal swamp waters and inversely correlated with ph speciation calculations using a modified version of the well established humic ion binding model v predict that organic matter complexes are the predominant form of dissolved rees in great dismal swamp waters despite significant competition from aqueous fe and al for organic matter binding sites adsorptive cathodic stripping voltammetry acsv was employed using a previously developed competitive ligand equilibration approach that involved adding the o cresolphthalexon ocp ligand to directly investigate ree complexation with natural organic ligands in great dismal swamp waters although preliminary the results of the acs voltammetric titrations are consistent with dominance of organic matter complexes of rees in great dismal swamp waters the results of the speciation modeling and the voltammetric titrations all point towards control of dissolved rees in great dismal swamp waters by complexation of these heavy metals with natural organic matter

salinity of the eocene arctic ocean from oxygen isotope analysis of fish bone carbonate stable isotope analysis was performed on the structural carbonate of fish bone apatite from early and early middle eocene samples 55 to 45 ma recently recovered from the lomonosov ridge by integrated ocean drilling program expedition 302 the arctic coring expedition the 18o values of the eocene samples ranged from 6 84 to 2 96 vienna peedee belemnite with a mean value of 4 89 compared to 2 77 for a miocene sample in the overlying section an average salinity of 21 to 25 was calculated for the eocene arctic compared to 35 for the miocene with lower salinities during the paleocene eocene thermal maximum the azolla event at 48 7 ma and a third previously unidentified event at 47 6 ma at the azolla event where the organic carbon content of the sediment reaches a maximum a positive 13c excursion was observed indicating unusually high productivity in the surface waters

rare earth elements in solnhofen biogenic apatite geochemical clues to the palaeoenvironment rare earth element ree concentrations in biogenic apatite samples coprolite bone and soft tissue were used to investigate the environment of deposition of the celebrated solnhofen fossil lagerstatten the measured ree patterns are similar between different localities lithologies flinz faule and levels in the upper solnhofen plattenkalk suggestive of a stable ree supply during deposition the behaviour of cerium in the solnhofen samples implies that bottom water conditions were not anoxic and variations in the cerium anomaly can be explained by differences in burial rate these results provide further geochemical support for current depositional models barthel k w 1978 solnhofen ein blick in die erdgeschichte ott verlag thun barthel k w swinburne n h m conway morris s 1990 solnhofen a study in mesozoic palaeontology cambridge univ press cambridge that propose that extra basinal processes are responsible for the interbedded nature of the solnhofen deposits rather than intra basinal processes such as water turnover events

high resolution records of location and stratigraphic provenance from the rare earth element composition of fossil bones abstract bone apatite acts as a natural timed sampling device scavenging trace elements from local pore waters over timescales of ca 1 50 ka the rare earth element ree and u th composition of fossil bones reflects associated pore water compositions during the period of recrystallisation the ree composition of fossil bones is controlled by partitioning of ree between pore waters and particle surfaces and the ree composition of fossil bones reflects the ree composition of pore waters which vary spatially and temporally light ree are preferentially sorped onto particle surfaces thus the high la yb values seen in many bones from coastal marine and aeolian environments are best explained by release of ree from light ree enriched particles to local pore waters and subsequent immobilisation in recrystallising bones the ree compositions of bones recovered from pedogenically altered diatomite sediments of the olorgesailie formation of southern kenya vary over spatial scales of less than 10 m location accounts for 48 of the observed variation in bone chemistry and bones recovered from eight discrete excavations within the same time equivalent stratigraphic layer can be assigned to their excavation location with 70 accuracy based on a discriminant analysis of ree u and th composition despite this within layer variation bones recovered from different stratigraphic horizons within the olorgesailie formation can also be distinguished on the basis of their trace element composition bones recovered from four stratigraphic horizons spanning ca 0 5 million years were assigned to their correct stratigraphic layer with 90 accuracy where sedimentological conditions are favourable the trace element composition of fossil bone may be used to test stratigraphic provenance and burial location in excavated bone with a temporal resolution of

solubilities of bone mineral from archaeological sites the recrystallization window abstract bone mineral solubility is an important parameter for understanding the preservation of bones in the archaeological and palaeontological records in this study we have measured the solubility of the carbonated hydroxyl apatite of sub recent and fossil bones as well as synthetic hydroxyl apatite in deionized water and in ph buffered solutions the solutions were open to the atmosphere and the ph values were around neutral measurement conditions that are relevant to bone mineral preservation in nature but that were absent from most previous studies we obtained internally consistent results from both the water and the buffered experiments supporting the notion that we are measuring an inherent property of the mineral phase we found that bone mineral is much more soluble than synthetic hydroxyl apatite we measured the ionic activity products at steady state conditions and we identify a recrystallization window between ph 7 6 and 8 1 which defines the conditions under which bone crystals dissolve and reprecipitate as a more insoluble form of carbonated hydroxyl apatite as these conditions are common in nature most fossil bones will not maintain their original crystals with time we also found that bones that contained small amounts of calcite did not dissolve at all during our experiments these results provide a basis for better understanding the conditions in sediments under which bones are preserved and the relative states of preservation of bone they also have important implications for the selection of the most appropriate bone samples for paleoenvironmental and paleodiet analyses and dating

rare earth element evolution of phanerozoic seawater recorded in biogenic apatites rare earth element ree contents of marine biogenic apatites have been shown to record seawater compositions a data base of available and newly acquired rare earth element ree contents of marine biogenic apatites has been created to assess the past seawater ree compositions to ensure that this data base contains only the pristine ree signals altered samples characterized by very low la sm n ratios where n stands for ree ratios normalized to the nasc composition gromet et al 1984 geochim cosmochim acta 48 1984 2469 acquired during apatite recrystallization are not included in the database these data reveal a change in the tethyan seawater composition between 110 and 80 ma after the end of the cretaceous the ree chemistry of seawater remains constant until present day this seawater composition change is likely due to concurrent changes in ree scavenging processes a strong correlation between decreasing sm yb n ratios and increasing ce anomalies for samples deposited during the 80 110 ma period is observed as ce anomalies are attributed to ocean water redox conditions changes in ree scavenging could reflect an evolution from stratified and poorly oxygenated waters towards well mixed and oxygenated waters this could have resulted from changing current patterns stemming from the contemporaneous opening of the atlantic ocean a major change in middle and late cretaceous oceanic circulation linked to plate tectonics would have favored the colonization of pelagic environments

preservation of successive diagenetic stages in middle triassic bonebeds evidence from in situ trace element and strontium isotope analysis of vertebrate fossils abstract bonebeds comprise reworked and time averaged constituents of different phosphatic vertebrate remains and hence provide an ideal substrate for the study of long and short term diagenetic processes to test whether trace elements u sr ree and 87 sr 86 sr ratios can be used for distinguishing between successive diagenetic signals we performed geochemical analyses on vertebrate remains bones teeth scales and coprolites from two triassic bonebeds located near palzem germany trace element analysis was done on 170 vertebrate remains by la icp ms while 87 sr 86 sr ratios were determined for 39 bioclasts using la mc icp ms although a low inter and intra bioclast ree variability indicates long term open system behaviour the observed ree patterns suggest the preservation of different diagenetic stages a distinct difference in the geochemical composition exists between dark luminescent sem cl domains and greyish ones dark domains represent dense diagenetically more resistant material of low porosities such as enamel and ganoine these domains display distinctly lower ree contents and a higher inter clast variability than those of various grey tones together with lower hence more seawater like 87 sr 86 sr ratios this argues for a preservation of an earlier diagenetic signal notably most dark domains are characterised by negative eu anomalies while all grey ones display positive eu anomalies with the exception of eu both domains display almost identical ree patterns with different concentrations indicating that late diagenetic ree uptake is not necessarily accompanied by fractionation processes in vertebrate bioclasts negative eu anomalies are most likely inherited from eu depleted surface waters possibly as a result of eu depleted aeolian input conversely positive eu anomalies were presumably affected by eu enriched late diagenetic fluids with a possible high temperature origin causing a fractionation of europium our study therefore demonstrates the potential of high resolution geochemical analysis in bonebed strata to disentangle different stages of diagenesis and to detect least altered areas in vertebrate fossils for recovering pristine palaeoenvironmental signals

protracted diagenetic alteration of ree contents in fossil bioapatites direct evidence from lu hf isotope systematics abstract fossil bones and teeth are potentially important repository for geochemical proxy data and a target for radiometric dating the concentration of many trace elements in bones and teeth increases by orders of magnitude after death and it is this diagenetic incorporation that forms the basis for several areas of geochemical study the use of bones and teeth in this context relies on two assumptions first that target metal ions are incorporated rapidly after death reflecting a known environmental signal and second that after early incorporation the bone or tooth remains as an essentially closed system resistant to later diagenetic change a wide literature has developed exploring these assumptions but relatively little direct evidence has been used to assess the long term diagenetic stability of trace elements within bones and teeth in this study we use the lu hf isotope system to show that bones and teeth of cretaceous and triassic age from both terrestrial and marine settings experience continued long term diagenetic change most likely through gradual addition of trace elements modelling suggests that diagenetic addition after initial recrystallisation may account for 50 of the total ree content in the sampled bones the extent depending on initial uptake conditions tooth enamel and enameloid may be more resistant to late diagenetic changes but dentine is probably altered to the same extent as bone these results have significant implications for the use of bones and teeth as hosts of chronological palaeoceanographic palaeoenvironmental and taphonomic information particularly in mesozoic and palaeozoic contexts

patterns of chemical change during bone fossilization the uptake of elements by bone during fossilization is a well recognized phenomenon but the nature of and the factors leading to chemical heterogeneity in fossil bone are only just starting to be elucidated indeed in the recent past the assumption that fossil bone is chemically homogeneous has been commonly used in several investigations including those of bone dating and dietary studies in an attempt to understand the processes of element uptake we have investigated some chemical heterogeneities in a fossil bone and have assessed the potential use of bone composition as an indicator of the trace element contents of associated groundwater our study extends other work1 2 by giving the first analysis of rare earth element ree distribution in a fossil bone and by showing that information on the redox state and ree abundance pattern of the groundwater can be obtained the results contribute to the interpretation of bone analyses in studies on provenance and age determination as well as in the diet and health of past populations

geochemical study of vertebrate fossils from the upper cretaceous santonian csehbanya formation hungary evidence for a freshwater habitat of mosasaurs and pycnodont fish abstract the diverse vertebrate remains from the upper cretaceous freshwater settings at iharkut hungary contain two fossil groups pycnodontiformes fish and mosasauridae that are almost exclusively known from marine palaeo environments hence their appearance in alluvial sediments is very unusual trace element and isotope compositions of the remains have been analyzed to investigate the taphonomy and the ecological differences among the different fossil groups present at iharkut all examined fossils have undergone post depositional diagenetic alteration which resulted in high concentrations of ree u and fe together with almost complete homogenization of 18oco3 values similar ree patterns in different fossils suggest a common origin for all remains hence the discovered species most likely lived in the same local ecosystem despite partial diagenetic overprinting the 18opo4 values of the fossils indicate sufficient taxon specific isotopic diversity to permit some broad conclusions on the palaeo environment of the fossils in particular it is apparent that the isotopic composition of the pycnodontiformes fish and mosasauridae remains is most compatible with a freshwater palaeo habitat and incompatible with a marine palaeo environment in addition the sr concentration and isotope data indicate that the pycnodontiformes and mosasauridae likely lived predominantly in a freshwater environment and were not simply occasional visitors to the iharkut river ecosystem regarding other fossil groups high 18opo4 values of alligatoroidea and iharkutosuchus teeth suggest that these small crocodile species might have inhabited swamps and ponds where the water was relatively rich in 18o due to evaporation

ion probe measurement of rare earth elements in biogenic phosphates abstract the rare earth element ree distributions in individual fish teeth and conodonts have been measured by ion probe concentrations and la yb ratios show little variations except in the enamel which suggests that ree uptake from the sedimented biogenic debris takes place at the water sediment interface as an essentially quantitative process without fractionation late diagenetic disturbances remained of marginal importance hence ree in phosphatic debris might reflect the input from the overlying water column

patterns of diagenesis in bone i the effects of site environments abstract we have measured a suite of diagenetic parameters for several populations of archaeological bones buried in a number of northwest european sites since the last ice age these are the structural damage due to microbes changes in bone micro and macro porosity protein content a measure of the crystallinity of hydroxyapatite as reflected in the phosphate infra red spectrum peak splitting and a measure of the carbonate content as given by the ratio of carbonate to phosphate infra red absorption peaks the results provide a database that clearly characterises the patterns which are often site dependent of diagenetic change in buried bone our main conclusions are that individual site hydrology appears to have a strong influence on the outcome of bone preservation and that porosity is the most effective single diagenetic parameter which both determines and reflects the preservation of bone in the burial environment

first cosmogenic 10be age constraint on the timing of younger dryas glaciation and ice cap thickness western scottish highlands we use cosmogenic 10 be surface exposure age techniques at a locality close to rannoch moor western scottish highlands in order to establish the age and chronology of its most recent glaciation glacial erratics and an in situ bedrock quartz vein sampled from this site the summit of beinn inverveigh have yielded zero erosion exposure ages of 12 9 1 5 ka to 11 6 1 0 ka implying complete ice cover of the mountain during the younger dryas or loch lomond stadial these results fit closely with published 14 c dates that bracket the maximum lateral extent of ice cap outlet glaciers and are the first internally consistent ages to specifically address this period of glaciation in scotland furthermore the dates imply that previous palaeoglaciological reconstructions for this area may have underestimated both the thickness of the former ice cap and by implication its volume british geological survey natural environment research council copyright 2007 reproduced with the permission of bgs nerc published by john wiley sons ltd

crystal chemical controls on rare earth element concentrations in fossil biogenic apatites and implications for paleoenvironmental reconstructions abstract fossil biogenic apatites display rare earth element ree patterns which have been proposed to reflect environmental and biological controls on past seawater composition these patterns can be separated in two groups 1 patterns that are similar to those of open ocean and epicontinental waters and 2 patterns that exhibit a strong enrichment in intermediate ree bell shaped patterns because ree trapping in biogenic apatites occurs mostly post mortem it is essential to understand the crystal chemical inorganic factors that can influence the fractionation of ree between apatite and water a model is proposed by which partition coefficients of ree between apatite and water for a substitution mechanism can be extrapolated from mineral melt partition data to seawater or sedimentary basin conditions these are compared with available experimental partition coefficients for ree adsorption mechanism and used to discuss ree patterns in fossil biogenic apatites calculations of ree patterns for apatites at equilibrium with water show that the bell shaped patterns in fossil apatites can be explained by fractionation with seawater or continental fluids at low temperature under crystal chemical control involving a substitution mechanism and in the context of extensive or late diagenesis in that case the equilibrium composition of the fluid cannot be unequivocally determined from observed ree concentrations in fossil apatites this type of sample is inappropriate to discuss the past environmental or biological controls on ree concentrations in the ocean other sample compositions suggest little to moderate alteration of the original oceanic to freshwater pattern through the adsorption mechanism in the context of weak or early diagenesis and may be used with caution for that purpose

composition and structural features of two permian parareptile deltavjatia vjatkensis kotelnich site russia bone fragments and their alteration during fossilisation abstract the kotelnich vertebrate fossil site one of the richest of the permian period is characterised by the excellent preservation of fossil remains due to their burial in a silty anaerobic environment similar to modern peat bogs the aim of the work is to carry out a comprehensive study of the composition and structure of bone fragments of the permian parareptile deltavjatia vjatkensis as well as that of its embedding rocks to support further paleoecological and fossilisation reconstructions fossil bones and their surrounding strata were investigated using optical and scanning electron microscopy raman spectroscopy x ray diffraction and inductively coupled plasma mass spectrometry icp ms the carbonate rich composition of the sediment was found to favour the preservation of the bone apatite the mineral phase of the bone tissue corresponds to fluorapatite organic matrix vibration bands arising on the raman spectra correspond to c h vibrations of lipids and proteins and possibly cholesterol the obtained data indicate a high degree of integrity of both bone mineral phase and its organic proteinaceous residue white blood cell wbc like structures were detected which possibly could be interpreted as leukocytes elemental mapping of fossil bones was used to reveal element distribution features uniform or with zones of apparent enrichment depletion and secondary mineralisation zones ca p mg mn and s are uniformly distributed through the bone conversely elevated quantities of fe are assigned to cracks and large pores formed as a consequence of the decomposition of organic materials as compared to bone apatite the authigenic calcite filling of bone porosities is significantly depleted in terms of microelements the apatite rare earth element ree composition of bone tissue which is inherited from seawater can be used for paleoreconstructions of redox conditions and water composition la sm ratios 0 4 0 5 high y ho ratios high uranium content and high la yb ratios 2 3 in the bone apatite indicate the absence of recrystallisation during the late stages of diagenesis a positive cerium anomaly detected in the bones indicates the presence of an oxidising and possibly alkaline environment during the early stages of diagenesis in shallow coastal basin of the kotelnich paleolocality it is shown that 10 to 20 of ree in bone apatite is derived from seawater absorption hydrogenous source with the remainder having been derived from host rock lithogenic sources

la icp ms analysis of rare earth elements in marine reptile bones from the middle triassic bonebed upper silesia s poland impact of long lasting diagenesis and factors controlling the uptake abstract the rare earth elements ree contained in fossil bones are widely used for provenance and palaeoenvironmental studies earlier works suggested that the ree uptake is limited to early diagenesis but more recent research provided evidence of long term open system diffusion in fossil bones we analysed thin walled reptile bones all collected from the same middle triassic 245 ma marine bonebed comprising vertebrate remains of likely different ages to check the influence of the long term diagenesis on the concentrations of ree in terms of impact of pore water the upper parts of the bones are contained in a low permeability crinoidal limestone whereas their lower parts have been affected by diagenetic fluids for a long time we measured ree and other trace element contents in 29 bones using la icp ms totally 660 spots in 45 depth profiles neither the absolute concentrations of the ree and the ree intra bone paas normalised patterns nor the inter element ratios and the la ce and eu anomalies appear useful to distinguish between the likely older and younger bones in the bonebed the mree n enrichment combined with the flat intra bone distributions of the ree lead to conclusion that ree fractionation and substitution for ca were the most important processes responsible for the selective uptake the low permeability host rock and diagenetic fluids had a significant impact on the trace element uptake and their intra bone distribution patterns the lower parts of the bones that likely had a long lasting contact with the diagenetic fluids reveal a relative enrichment in the ree and their easier diffusion into the bone centres the ability of fossil bones to incorporate trace elements over a long time span strongly limits the usage of particularly the older samples for provenance and palaeoenvironmental reconstructions additionally the presented new analyses fill the gap between the available databases of trace element concentrations in fossil bones with regard to middle triassic samples

stratigraphic interpretation of rare earth element signatures in pleistocene mammal bones a case study from kharabai site east siberia a significant portion of the quaternary mammal remains is not found in situ which limits their biostratigraphic potential and the possibility of studying evolutionary changes to determine stratigraphic position of such finds we used the geochemical interpretations of rare earth element relative concentrations and fractionations ree signatures in the faunal remains and surrounding sediments ree signatures vary between different profile deposits due to differences in deposit sources conditions and ree fractionation during deposition and diagenesis redeposited faunal remains can retain evidence of unique ree signatures of surrounding deposits which allows assigning such bones to their proper depositional units this method is tested here on the material from the kharabai site viluy river central yakutia 63 77 n 121 10 e we determined that the ree signatures from the faunal remains collected at the base of the exposure showed a statistically significant correspondence to certain stratigraphic layers indicating the original deposition location of these remains importantly the biochronological age of the mammals determined using their evolutionary position was consistent with the stratigraphic position of the layers with which they were associated using the ree signatures this research suggests that the lower layers of the kharabai site date to early middle pleistocene while the upper ones date to late pleistocene

anthropogenic units fingerprinted by ree in archaeological stratigraphy mas d is spain case abstract on occasions archaeologists have to deal with serious difficulties to differentiate between processes that ultimately are responsible for the formation of stratigraphic units sometimes we face problems related with depositional units in multilayered deposits and other times we ask for the character of some dark surface soils very similar to natural paleosols and usually associated with archaeological findings in both cases the problems we must address concern the relative impact of human activities the imbalance between anthropic and natural processes in the formation of archaeological deposits is crucial for a correct interpretation of the processes involved in the formation of archaeological sites but also of their occupation abandonment dynamics and the understanding of their spatial behaviors and relationship with the environment in this paper we propose a new methodological approach for the identification of anthropogenic fingerprints in stratigraphic units through rare earth elements ree soil analysis the role of ree for the effective identification of sediment provenance due to their coherent behavior during weathering erosion and fluvial transportation and their high resistance to chemical mobilization is well known in other areas of knowledge we try to explore its potentiality in a challenging archaeological context our purpose was to identify human traces in stratigraphic units where archaeological materials are scarce or absent intertwined with others richer in archaeological remains by the determination of multiple elements and statistical studies we believe that rare earth elements ree soil analysis provides unique insights for a better characterization of natural and archaeological sediments but more importantly to recognize different stages of the gradient we expect to discern between natural versus anthropic units and between primary versus secondary deposits redeposition using the case of the neolithic site of mas d is alicante spain as an example the application of the principal component analysis pca remarks differences in ree values those analysis show differences between units of undoubtedly anthropogenic origin and control samples taken from natural sediments including marls bedrock in their vicinity but also we could notice finer nuances like the degree of human contributions to paleosols formation

a geochemical method to trace the taphonomic history of reworked bones in sedimentary settings rare earth element ree signatures can be used to identify the original mode of deposition of fossil bones and teeth that have been reworked this new technique may resolve the notoriously difficult problem of assessing the amount of transport or reworking undergone by fossil bones and teeth on the basis of physical parameters such as degree of abrasion different ree signals characterize different pore water environments bones and teeth composed of apatite incorporate rees rapidly during early diagenesis and the ree signature in the bone is controlled by that of the surrounding pore waters reworked bones and teeth may show ree traces suggesting early diagenetic pore water conditions different from those indicated by in situ sedimentary or geochemical evidence this situation is demonstrated in a case study from the rhaetian latest triassic of southwest england where different bone beds are compared in one case the original environmental setting of reworked bone is traced by matching ree traces with contemporaneous unreworked bone assemblages in neighboring areas

l apatite de durango mexique analyse d un mineral standard pour la datation par traces de fission abstract durango apatite is analyzed by four analysts using three different dating techniques both the annealing technique and the external detector technique are applied to basal and prismatic sections cut from single crystals the population technique is applied to mounts of randomly oriented grains provided an individual determination of the geometry factor is performed all ages are indistinguishable from the reference age of 31 4 0 5 ma there is no noticeable influence of either the dating technique or the crystallographic orientation of the dated section on the ft age based on the projected lengths of surface tracks spontaneous track length reduction varies from 4 to 10 mean 6 depending on the analyst two simple corrections are applied to eliminate the net effect of the missing short tracks on the mean projected length after correction the amount of shortening of the spontaneous tracks is found to be slightly larger mean 8 but is still dependent on the analyst 4 to 12 the mean is in fairly good agreement with the value obtained from confined track length measurements 9 finally an isochronal 1 h plateau annealing procedure was applied to a separate set of basal and prismatic sections cut from the same single crystals annealing temperatures up to 300 c do not affect the ft age erratic ages at 350 c are ascribed to the occurrence of unetchable gaps it is argued that the absence of a distinct plateau up to temperatures where it could be expected from theoretical considerations indicates that the ft age of durango apatite needs no correction

surface water freshening and high latitude river discharge in the eocene north sea abstract a shark tooth apatite 18 o record of the early palaeogene north sea reflects changes in regional hydrography by showing variable temperatures and salinities a 2 4 ma period in the early eocene was particularly influenced by substantial surface water freshening indicated by a 3 4 reduction of 18 o values the magnitude of the 18 o decrease indicates a depletion in 18 o of surface waters by 2 3 relative to eocene mean ocean water this value is lower than that of coeval lakes reconstructed from freshwater gastropod 18 o values from the paris basin suggesting that large rivers with high latitude catchment areas drained into the north sea the period of surface water freshening began close to the palaeocene eocene thermal maximum when relative sea level fall tectonic uplift and basaltic volcanism caused a temporary isolation of the north sea north atlantic and north sea surface waters became reconnected during a series of early eocene transgressions

rare earth distributions with a positive ce anomaly in the western north atlantic ocean from the vertical distributions of the rare earth elements ree in the sargasso sea we now report the first profiles of pr tb ho tm and lu in seawater together with profiles for la ce sm eu and yb the first observations of positive ce anomalies in seawater are ascribed to reducing inshore sediments as a source for ce ref 1 all vertical profiles are consistent with adsorption of trivalent rare earths by settling particles possibly siliceous or calcareous followed by their release at or near the sea floor on dissolution of the carriers the very different ce profile demonstrates the additional effects of oxidation reduction reactions

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

rare earth elements in old biogenic apatites abstract the ree distributions in individual upper devonian conodonts have been measured by ion probe the patterns of all analyzed conodonts are enriched in middle ree eu gd and have a weak or no ce anomaly concentrations and la yb or la sm ratios vary very little within or among individuals from the same zone which suggests that uptake of labile ree from sediments was essentially quantitative therefore the ree signature of the primary carriers probably organic and oxyhydroxides particulates from marine suspensions was efficiently transferred to biogenic apatites and survived late diagenetic processes ree patterns of conodonts do not resemble those of present day seawater and post cretaceous biogenic phosphates which are typically depleted in nd and sm with a negative ce anomaly since ree distributions in the modern water column mimic those of nutrients we assume that in pre cretaceous seawater they were not controlled by surface biological activity we assume instead that ree in pre cretaceous seawater can be explained by mechanism of desorption adsorption on particle surfaces progressive extraction of lree from river water by oxyhydroxides leads to precipitates enriched in middle ree a simple quantitative model was calculated in order to illustrate the proposed mechanism

rare earth element geochemistry of groundwaters from a thick till and clay rich aquitard sequence saskatchewan canada rare earth elements ree were determined in groundwater samples collected from a thick till and clay rich aquitard sequence located in southern saskatchewan canada the groundwaters are na mg so4 type waters that range from highly concentrated brines e g i up to 2 moles kg near the ground surface to relatively dilute waters i 0 04 moles kg at depth the majority of these groundwaters have ph values between 7 and 8 although the deepest samples are more alkaline 9 ph 9 6 groundwater ree concentrations are relatively constant in the overlying till but increase by up to a factor of 50 in the underlying clay bedrock shallow groundwaters have heavy ree hree enriched shale normalized patterns whereas the ree patterns of the deep groundwaters are relatively flat solution complexation modelling indicates that variations in ree patterns reflect differences in solution complexation across the ree suite in the shallow groundwaters strongly adsorbed positively charged carbonate complexes lnco3 sulfate complexes lnso4 and free metal ion species ln3 dominate the speciation of light rees lree whereas hrees occur chiefly as more stable negatively charged dicarbonato complexes i e ln co3 2 for the deepest groundwaters however all of the rees are predicted to occur in solution as dicarbonato complexes the large hree enrichments of the shallow groundwaters reflect the greater affinity of the positively charged lree solution species to adsorb to clay minerals or coatings on clay minerals in the aquitard sequence compared to the more stable negatively charged hree dicarbonato complexes on the other hand the flat ree patterns of the deep groundwaters reflect the dominance of the negatively charged dicarbonato complex for all rees the solution complexation model along with the strong positive correlation between rees and co32 f 0 79 r 0 95 and to a lesser extent ph 0 57 r 0 72 indicates that carbonate ion concentrations and thus ph exert important controls on aqueous ree concentrations in these groundwaters

rare earth element composition of paleogene vertebrate fossils from toadstool geologic park nebraska usa fossil bones and teeth from terrestrial environments encode unique rare earth and trace element ree and te signatures as a function of redox conditions ph concentrations of complexing ligands and water colloid interactions this signature is set early in the fossilization process and serves as a paleoenvironmental and paleoclimatic proxy these signatures can also be used to interpret temporal and spatial averaging within vertebrate accumulations and can help relocate displaced fossil bones back into stratigraphic context rare earth elements in vertebrate fossils from upper eocene and oligocene strata of toadstool geologic park northwestern nebraska record mixing and evolution of paleogene vadose or groundwaters and variations in paleoenvironments ree signatures indicate that hree enriched alkaline groundwater reacted with lree and mree enriched sediments to produce 3 component mixtures ree signatures become increasingly lree and mree enriched toward the top of the studied section as the paleoenvironment became cooler and drier suggesting that ree signatures may be climate proxies time series analysis suggests that ree ratios are influenced by cycles of ca 1050 800 570 440 and 225 ka similar to some previously determined milankovitch astronomical and climate periodicities

multiproxy reconstruction of the palaeoclimate and palaeoenvironment of the middle miocene somosaguas site madrid spain using herbivore dental enamel profound palaeoclimatic changes took place during the middle miocene the miocene climatic optimum 20 to 14 13 5 ma was followed by a sudden 200 ka decrease in temperature and an increase in aridity around the world as a consequence of the reestablishment of the ice cap in antarctica somosaguas palaeontological site madrid basin spain has provided a rich record of mammal remains coincident with this global event middle miocene biozone e 14 1 13 8 ma it contains four fossiliferous levels t1 t3 1 t3 2 and t3 3 with t1 being the oldest that span an estimated time of 105 125 ka scanning electron microscope sem and rare earth element ree analyses performed on herbivore tooth enamel gomphotherium angustidens anchitherium cf a cursor conohyus simorrensis prosantorhinus douvillei and ruminants indicate that diagenetic processes have not been intense enough as to obscure the original geochemical signal stable isotope 18oco3 13cco3 and 18opo4 analyses have been measured on the herbivore tooth enamel across these levels with the aim of determining to what extent the global cooling and aridity pattern is recorded at this site a decrease in 18oco3 and 18opo4 has been detected from t1 to t3 3 and t3 1 to t3 3 respectively indicating a progressive drop of about 6 c from around 18 c to 12 c in mean annual temperatures within t3 tooth enamel 13c values experience an increase from t3 1 to t3 3 suggesting an increase in aridity ba ca analyses have also been performed on the tooth enamel in order to detect changes in the palaeoecology of the studied taxa this ratio allows the establishment of particular feeding patterns such as a more browsing habit in the case of gomphotherium angustidens compared to anchitherium cf a cursor as suggested by higher ba ca values in the latter trace elements do not support any significant change across the succession in the dietary behaviour of the species analyzed despite the stable isotopes evidence of an important palaeoclimatic shift from t1 to t3 3

origin of archaeological black bones within a waterlogged context a multidisciplinary approach abstract this paper presents the interdisciplinary study on the origin of black bones at the neolithic lakeside settlement of dispilio greece 5500 3500 bce where animal bones have been recovered from a waterlogged and organic soil matrix containing charcoal ash and burnt cultural remains in the past this has been interpreted as the result of the destruction of the village by fire and abandonment this study aims to examine this theory through the distinction of burnt vs oxide stained bones a selection of 44 fish and 19 mammal bone samples are examined through optical microscopy scanning electron microscopy sem x ray microanalysis eds x ray diffraction xrd rietveld analysis infrared spectroscopy atr nir and chemical analyses icp ms alterations of histology mineralogy chemistry crystallinity and structural parameters prove that the black bones from dispilio owe their colour to mn and fe oxide staining light coloured bones found at the site have not been affected by this diagenetic procedure which suggests that they were buried in a totally different geochemical environment the analytical techniques employed did not offer any proof that the studied material is burnt however due to the fact that most techniques used to this day allow for the identification of thermal alteration of bone at temperatures usually higher than 300 450 c the possibility of thermal alterations due to an indirect fire thus at lower temperatures or a fire of small duration cannot be identified and thus be ruled out

visualizing fossilization using laser ablation inductively coupled plasma mass spectrometry maps of trace elements in late cretaceous bones elemental maps generated by laser ablation inductively coupled plasma mass spectrometry la icp ms provide a previously unavailable high resolution visualization of the complex physicochemical conditions operating within individual bones during the early stages of diagenesis and fossilization a selection of la icp ms maps of bones collected from the late cretaceous of montana united states and madagascar graphically illustrate diverse paths to recrystallization and reveal unique insights into geochemical aspects of taphonomic history some bones show distinct gradients in concentrations of rare earth elements and uranium with highest concentrations at external bone margins others exhibit more intricate patterns of trace element uptake related to bone histology and its control on the flow paths of pore waters patterns of element uptake as revealed by la icp ms maps can be used to guide sampling strategies and call into question previous studies that hinge upon localized bulk samples of fossilized bone tissue la icp ms maps also allow for comparison of recrystallization rates among fossil bones and afford a novel approach to identifying bones or regions of bones potentially suitable for extracting intact biogeochemical signals

effect of paleosol formation on rare earth element signatures in fossil bone the rare earth element ree content of fossil bones was analyzed and compared with the degree of ancient pedogenic development and depositional environments from several locations in the orellan scenic member of the oligocene brule formation in badlands national park south dakota paleosols ranged from weakly developed entisols to more strongly developed inceptisols all typical of fluvial environments and possible paleocatena variation paleosols were alkaline and well drained sediments with sparse soil features from an oxbow lake system suggest that conditions were too waterlogged and sedimentation rates too rapid for significant pedogenesis the variance of ree signatures in fossil bones from the paleosol sites was significantly greater than that of fossils from minimally altered sediments of the former oxbow lake positive ce anomalies were associated with low u concentrations and indicate paleoredox conditions greater degrees of pedogenesis regardless of the horizon in which the bone was found systematically correlated with increased heavy ree enrichment in fossil bones the fossil bone ree signatures from the different paleosols and depositional environments were significantly different and distinguishable

rare earth element contents of jurassic fish and reptile teeth and their potential relation to seawater composition anglo paris basin france and england the rare earth element ree chemistry of jurassic shelf seawater from western europe anglo paris basin was investigated by analyzing the fish and reptile teeth deposited in shallow to deeper water 200 m environments ree patterns in apatites are controlled by the host sediments vertebrate teeth sampled from the siliciclastic sediments calcareous sandstones and shales show flat shale normalized ree patterns that reflect the dominant influence of the continental source from which the ree were derived carbonate deposits protected from the clastic sources contain fish and reptile teeth whose ree patterns reflect more accurately the ree composition of the overlying water column the ree patterns are similar through the bajocian to the oxfordian and are characterized by a depletion in heavy rare earth element dy ybn 1 8 5 0 compared to modern seawater compositions dy ybn 0 8 0 9 the fractionations among hree in the jurassic seawater are more efficient than in modern oceans and increases with depth instead of decreasing these hree removal processes operated as early as the paleozoic and disappeared during the late cretaceous the fractionation of hree relative to lree is correlated with the increasing depth of the basin as indicated by two independent criteria that are the sedimentary structures and the oxygen isotope composition of coexisting brachiopods the dy ybn ratio of the marine biogenic phosphates can be used as a proxy of paleo water depths at the scale of a water mass ce anomalies ce in biogenic apatite bearing limestones are variable and systematically negative relative to modern surface seawater and bathonian values mean ce 0 63 0 10 weak ce anomalies during the callovian mean ce 0 21 0 09 suggest the onset of more reducing conditions this redox change coincided with an increase of seawater temperatures as suggested by the oxygen isotope compositions measured on the same teeth we speculated that the callovian low ce could result from a decrease in the po2 due to the warming of seawater

tohoku earthquake a surprise abstract we consider three questions related to the 2011 tohoku mega earthquake 1 why was the event size so grossly underestimated by japan s national hazard map 2 how should we evaluate the chances of giant earthquakes in subduction zones 3 what is the repeat time for magnitude 9 earthquakes off the tohoku coast the maximum earthquake size is often guessed from the available history of earthquakes a method known for its significant downward bias we show that historical magnitudes systematically underestimate this maximum size of future events but the discrepancy shrinks with time there are two quantitative methods for estimating the corner magnitude in any region a statistical analysis of the available earthquake record and the moment conservation principle however for individual zones the statistical method is usually ineffective in estimating the maximum magnitude only the lower limit can be evaluated the moment conservation technique which we prefer matches the tectonic deformation rate to that predicted by earthquakes with a truncated or tapered magnitude frequency distribution for subduction zones the seismic or historical record is insufficient to constrain either the maximum or corner magnitude however the moment conservation principle yields consistent estimates for all the subduction zones the corner magnitude is of the order 9 0 9 7 moreover moment conservation indicates that variations in estimated corner magnitude among subduction zones are not statistically significant another moment conservation method applied at a point on a major fault or plate boundary also suggests that magnitude 9 events are required to explain observed displacement rates at least for the tohoku area the global rate of magnitude 9 earthquakes in subduction zones predicted from statistical analysis of seismicity as well as from moment conservation is about five per century five actually happened

stable isotope chemistry of fossil bone as a new paleoclimate indicator abstract during fossilization bone is thought to recrystallize and alter chemically on timescales of kyr to a few tens of kyr i e similar to the timescale for formation of soils therefore c and o isotope compositions of bone apatite should correlate with trends in soil water composition and aridity and serve as paleoclimate indicators this hypothesis was tested by analyzing c and o isotope compositions of the co 3 component of fossil bone apatite from mid oligocene through late pleistocene units in oregon and western idaho including the john day 19 4 30 0 ma mascall 15 2 15 8 ma and rattlesnake 7 2 7 8 ma formations whose paleosol sequences have been studied in detail and the juntura 10 11 ma hagerman 3 2 ma and fossil lake 18 o values provide a baseline of meteoric water compositions stable isotope compositions of bone co 3 do change in response to broad climatic trends but show poor correlation with compositions of corresponding paleosol co 3 at specific horizons instead compositional deviations between bone and paleosol co 3 correlate with compositional deviations with the next higher paleosol this suggests that the timescale for fossilization exceeds one paleosol cycle based on stratigraphic evidence and simple alteration models fossilization timescales are estimated at 20 50 kyr indicating that bone co 3 will prove most useful for sequences spanning 100 kyr c isotopes show negative and strong positive deviations during wet and dry climates respectively and short term trends correspond well with changes in aridity within the mascall and rattlesnake formations as inferred from paleosols a proposed correction to 18 o values based on 13 c anomalies implies a small 1 5 increase in meteoric water 18 o during the late oligocene global warming event consistent with a minimum temperature increase of 4 c a strong inferred decrease in 18 o of 4 5 after 7 ma closely parallels compositional changes in tooth enamel and reflects a doubling in the height of the cascade range

identifying the geochemical taphonomy of the osteological material from katsambas rockshelter we report analytical work undertaken in order to identify the geochemical taphonomy of the osteological collection human and animal bones recovered from a 1950s excavation at katsambas a small cavity in the marly limestone on the west bank of kairatos river crete the site had funerary use and yielded material of neolithic and minoan age with poor stratigraphical association disintegration of provenance labels from bags has introduced further uncertainty about the contexts of recovery samples of human and animal bones that macroscopically appear to belong to three taphonomic categories were studied by means of ft ir spectroscopy tem microscopy and ree analysis to explore the taphonomical processes the bones have undergone although not novel in palaeontological research the use of ree opens a new path to investigating poorly provenanced osteological collections from old excavations such geochemical work offers a proxy to their relative dating through the evaluation of the time span bones have remained in the sediments and their respective taphonomic histories

fractionation of rare earth elements within bone mineral a natural cation exchange system the distribution of rare earth elements rees within fossil bones is controlled by their partition coefficients between apatite and pore waters and the rate of diffusion through the bone using simple theoretical models we show that rees are strongly fractionated from one another during diffusive transport and adsorption fractionation occurs due to the relative ease of substituting ree ions of differing ionic radius into the ca sites in the apatite lattice and the degree of fractionation is dependent on the rate of diffusion of ions within bone and therefore the rate of recrystallisation variations in bone thickness recrystallisation rate and potentially pore water composition may all influence the relative distribution of rees and thus ree ratios within bones increases in bone thickness and reductions in either diffusion coefficients or the duration of ree uptake lead to enhanced fractionation of rees in our model simulations interpretations of ree ratios in fossil bones either for palaeoenvironmental or taphonomic applications must consider how fractionation will influence ree ratios within bones particularly when interpreting spatially resolved analyses within single bones

paleoenvironmental interpretations of rare earth element signatures in mosasaurs reptilia from the upper cretaceous pierre shale central south dakota usa abstract rare earth elements were analyzed from fossil marine reptile mosasauridae bones collected from five superposed members sharon springs gregory crow creek degrey and verendrye of the upper cretaceous pierre shale at localities along the missouri river in brule buffalo hughes and hyde counties in central south dakota fossil bones from each member of the pierre shale have different rare earth element ree signatures that may be distinctive over wide geographic areas fossils from the sharon springs member have distinctive ree signatures that may be further subdivided into three superposed groups that correspond with the upper middle and lower sharon springs member ree signatures are distinctive from each stratigraphic unit therefore fossils eroded from their stratigraphic context may be assigned to their proper depositional unit based on ree signature comparisons differences in ree compositions of bones among members appear to result from differential mixing of oxygenated and anoxic seawaters if differences in mixing are interpreted as depth differences the lower sharon springs member was deposited in deep anoxic water water depths decrease in the middle and upper sharon springs and the overlying gregory and crow creek members were deposited in even more shallow water finally according to this interpretation the overlying degrey and verendrye members were deposited in progressively deeper marine waters but not as deep as the lower sharon springs these interpretations are generally consistent with those based on faunal diversity and eustatic sea level curves

the post mortem history of a bone revealed by its trace element signature the case of a fossil whale rostrum abstract studies dedicated to palaeoenvironments and taphonomy have made wide use of rare earth elements ree contents of fossil bones as proxies however the complex diagenetic history of individual specimens combined with intra bone ree fractionation and the uncertain timing of ree uptake generally prevents the robust interpretation of ree patterns in this case study we show that combining ree analysis with on the one hand histology and microstructural observations and on the other hand additional analyses of other trace elements allows deciphering at least three distinct trace element uptake stages as well as one leaching event more than 35 trace elements including the ree are analysed using laser ablation inductively coupled plasma mass spectrometry la icpms within compact rostrum bones of the miocene pliocene beaked whale globicetus hiberus from deep sea deposits and a comparable extant specimen blainville s beaked whale mesoplodon densirostris comparison of the extinct and the extant bones allows a better quantification of the diagenetic trace element content this study highlights the crucial role played by diagenetic minerals such as the fe mn oxyhydroxides in the uptake and release of trace elements co ni ti v zr hf and nb and ree by bones in response to changes of the diagenetic fluid redox conditions over time such changes of the geochemical environment help constraining the post mortem history of the bone and its interaction with diagenetic fluids we conclude that the unique interpretation of geochemical proxies within individual fossil bones requires a thorough investigation of each individual specimen

submicroscopic accessory minerals overprinting clay mineral ree patterns celadonite glauconite group examples abstract samples of glauconite representing different stages of glauconitisation as well as different formation environments were analysed for rare earth elements ree and other trace elements using a combination of bulk sample and spatially resolved in situ techniques the results indicate that the high sensitivity spatially resolved technique of laser ablation inductively coupled plasma mass spectrometry la icp ms produces values up to two orders of magnitude lower than the bulk sample analyses this suggests that submicroscopic rare earth element bearing phases are distributed within the glauconite aggregates comprising the bulk samples analytical scanning electron microscopy asem revealed the presence of micrometre sized grains of apatite and pore filling precipitates of an unidentified ree ca phosphate approximate composition ca 0 3 0 4 ce 0 4 la 0 1 0 2 nd 0 1 po 4 in some glauconite grains the inherent ree concentrations of the glauconite aggregates i e glauconite crystallites without accidental mechanical inclusions or authigenic not layer silicate mineral precipitates was found to be relatively low e g typically less than 100 ppm and this value decreased with increasing glauconitisation smectite mica transformation through a series of recrystallisation processes these results suggest that the rees substitute for ca in the interlayer space of the layer silicate structure and therefore the ree content decreases as ca is progressively removed from the interlayer smectite mica transition la icp ms when combined with electron probe microanalysis epma or asem offers an opportunity to exclude submicroscopic accessory minerals from glauconite trace element analyses and so produces reliable trace element data for the respective minerals which host those elements these results illustrate that accessory minerals are difficult to eliminate from clay samples and that care needs to be taken in the interpretation of clay mineral ree distributions irrespective of the aggregation state of the studied clay i e whether finely dispersed within the sedimentary rock or forming millimetre sized aggregates model calculations showed that authigenic apatite associated with the studied green marine clays tends to have higher ree content than bioapatites the total ree content being above 10 000 ppm

calibration of mammoth mammuthus dispersal into north america using rare earth elements of plio pleistocene mammals from florida the first appearance of mammoth mammuthus is currently used to define the beginning of the irvingtonian north american land mammal age at about 1 4 ma thereafter mammoth fossils are common and widespread in north america until the end of the pleistocene in contrast to this generally accepted biochronology recent reports have asserted that mammoth occurs in late pliocene ca 2 5 ma alluvium from the santa fe river of northern florida the supposedly contemporaneous late pliocene fossil assemblage from the santa fe river that produced the mammoth specimens actually consists of a mixture of diagnostic blancan late pliocene and late rancholabrean latest pleistocene species fossil bones and teeth of the two mammalian faunas mixed together along the santa fe river have significantly different rare earth element ree signatures the ree signatures of mammoth are indistinguishable from those of rancholabrean mammals yet they are different from those of diagnostic blancan vertebrates from these same temporally mixed faunas of the santa fe river thus no evidence for late pliocene mammoth exists in florida and mammoth fossils remain reliable biochronological indicators for irvingtonian and rancholabrean terrestrial sequences throughout mid and lower latitude north america

tologoi key section a unique archive for pliocene pleistocene paleoenvironment dynamics of transbaikalia bikal rift zone abstract the multi layered key section of tologoi is situated on the selenga river left bank 15 km southwest of ulan ude city 51o45 n 107o29 e in the western transbaikal region it holds a long record of quaternary sedimentation since early late pliocene through holocene with the only minor gap in the beginning of early pleistocene comprehensive studies have been carried out on the lithology geochemistry fauna succession and paleoenvironment reconstructions this paper summarizes the data acquired on the geology and stratigraphy of the tologoi section the authors investigated the composition structure and formation conditions of the section as well as the intensity of weathering rock geochemistry grain size and biostratigraphy

the distribution of rare earth elements in groundwaters assessing the role of source rock composition redox changes and colloidal particles rare earth element ree dissolved organic carbon doc and trace element al mn fe sr ba u and th concentrations were measured in fourteen well water samples 0 22 m and one spring located along two transects set up in a catchment from western europe kervidy coet dan catchment france previous hydrological and hydrochemical no3 so42 investigations demonstrated that three chemically and spatially distinct groundwater types are present in this catchment which is fully confirmed by the ree and doc results these include i a shallow organic rich groundwater 4 4 doc 34 6 mg l from the wetland areas close to the river network this first groundwater type characterized by the development of temporary reducing conditions records high and variable ree contents 2 ree 16 ppb and displays slight or no negative ce anomaly ce ce 0 8 1 05 ii a shallow organic poor doc 3 mg l no3 rich groundwater type 86 8 no3 155 mg l located in the weathered schists below the hillslope domains this second type corresponds to recently recharged oxidized water and displays also high and variable ree concentrations 2 ppb ree 15 ppb but distinguish from the former by the occurrence of very strong negative ce anomalies ce ce 0 05 0 10 finally iii a deep organic poor doc 1 mg l nitrate poor no3 close to 0 2 mg l detection limit groundwater this third type corresponds to reduced water flowing into the deep fresh schists and yields low to very low ree contents ree 0 15 ppb as well as slight negative ce anomaly ce ce 0 8 to 0 9 temporal ree concentration variations were assessed using samples regularly collected over a six month period results show that the spatially distributed ce anomaly and ree pattern signatures are preserved throughout the studied period by contrast ree concentrations are quite variable through time especially in the wetland waters where the ree concentrations are seen to vary in phase with both redox changes and doc fe u and th content variations three ree rich water samples one doc rich and two doc poor were also filtered through membranes of decreasing pore size 100 000 d 30 000 d 5 000 d the results show that between about 40 to 65 of the ree present in the shallow doc poor groundwater samples are controlled by the colloidal fraction which is likely to consist in these inorganic waters of a mixture of mineral phases in the wetland groundwaters the fraction of ree controlled by microparticles is higher than 65 which confirms the predominant role of organic colloids as major ree carriers in wetland waters using the above data set in conjunction with analyses of soil samples we show that the deep ce anomalies found in the upper non organic part of the aquifer are probably not source rock inherited features most likely these anomalies arise from the oxidative precipitation of ce the very low ree content displayed by waters flooding the deep fresh schists is interpreted as due to the combined effects of i ph variation ii secondary sulfate mineral precipitation and iii the trapping of colloids borne ree by the aquifer rock pores data from wetland groundwaters show that the ree fe u and th budgets of these waters are mainly controlled by seasonal changes in redox conditions and organic matter content however unlike organic poor waters it appears difficult to relate the ce behaviour in these organic rich waters solely to redox conditions it is likely that the complexation of ce by organic colloids in the organic rich waters may mask redox changes by inhibiting the development of negative ce anomalies

variability of trace element uptake in marine reptile bones from three triassic sites s poland influence of diagenetic processes on the host rock and significance of the applied methodology abstract diagenetic alternation of apatite building vertebrate bioclasts is a complex process it is influenced by numerous factors but the impact of diagenetic processes affecting the host rock is commonly underestimated the present study aims at identifying the causes of different concentration levels and distribution patterns of ree and at examining the significance of the material chosen for normalisation we measured ree and other trace element concentrations in three bone assemblages of triassic marine reptiles using la icp ms and in the host rocks using icp ms two groups of hard parts reveal clearly different trace element contents and distribution patterns the remains from gogolin show a distinct mreen enrichment which must have been caused by replacement involving numerous substitutions that was possible due to a relatively high porosity of the host rocks and the presence of pore water the mreen enrichment and low concentrations of mg and sr combined with a relatively high content of u in these bones indicate solutions derived from meteoric water as the source of the incorporated ions the reductive dissolution of fe oxyhydroxides that are abundant in the host rock matrix and that likely were an important source of ree may have influenced and controlled the ree uptake the significant hreen enrichment over lreen as revealed in the rust coloured bones from raciborowice gorne is likely connected with local acidification of the pore water resulting from aqueous oxidation of pyrite infilling the pore spaces in the bones the material selected for normalisation of the chemical composition of apatite can have a significant impact on values of the normalised data used further for interpretations particularly when vertebrate bioclasts from carbonate host rocks are involved the carbonate rocks have element ratios that differ from those characterising the commonly used paas and nasc normalisation materials in particular ce anomaly values can distinctly vary depending on the applied normalisation procedure vertebrate hard parts that definitely spent more time in a host rock than in an animal body must be rigidly handled as a constituent of a specific rock never as a separate item

geochemical taphonomy of shallow marine vertebrate assemblages abstract combined histological and geochemical analyses demonstrate complex processes leading to preservation of microbially altered bone in certain situations a chemical microenvironment distinct from surrounding pore waters is developed and maintained within the bone the bone acts as a closed system and hence palaeoenvironmental interpretations based on fossil bone apatite chemistry may not accurately reflect overall geochemical conditions of the sedimentary deposits where the bones were buried geochemical techniques based on variance in trace element compositions of bones from different assemblages can be used as a measure of the relative degree of mixing or taphonomic averaging within marine vertebrate assemblages

rolling bones taphonomy of jurassic dinosaur bones inferred from diagenetic microcracks and mineral infillings abstract dinosaur bones from the upper jurassic shishugou formation near qitai in the junggar basin nw china show black manganese oxide and light quartz infillings in the bone pore space such as haversian canals and diagenetic cracks the manganese oxides are identified by x ray diffraction as pyrolusite some haversian canals are only partially filled with pyrolusite which forms miniature geologic spirit levels the orientations of these spirit levels have been measured and several generations of pyrolusite infillings determined indicating that the bones were turned around once or several times during their fossilization characteristic desiccation cracks in the dinosaur bones indicate deposition on the soil surface and early diagenesis under dry climate conditions in the upper jurassic in nw china during dry season evaporation and resulting capillary forces drove the groundwater with dissolved manganese ii ions towards the soil surface and further into the capillary system of the bones hence the capillary system of the bones was already in contact with that of the sediment when the bones were still lying on the surface and were not yet totally embedded in the sediment mn oh 2 precipitated under high ph conditions in the pore space of the bones such as haversian canals and cracks during late diagenesis the mn oh 2 was oxidized to mno2 and transformed into pyrolusite mineral infillings and desiccation cracks in fossil bones thus can yield valuable insights into the taphonomic history of skeletal remains such as environmental conditions during diagenesis and fossil reworking

early diagenetic stabilization of trace elements in reptile bone remains as an indicator of maastrichtian late paleocene climatic changes evidence from the naran bulak locality the gobi desert south mongolia abstract maastrichtian dinosaur bone remains from the naran bulak locality the gobi desert with well preserved bone textural features are enriched in some trace elements primarily in ree these features of vertebrate fossils were formed during diagenesis following rapid burial in mudflow sediments and prior to postfossilization epigenetic changes trace elements are mainly concentrated in diagenetic apatite their contents in the bones correlate with that in their enclosing sediments for both maxima and minima fossil and sediment compositions were established under the influence of paleoclimate they are correlated with long term climatic changes with the aridity maximum at the k t boundary climatic changes were recorded via the change of salinity of waters interacting with the buried vertebrate remains

the variation of the trace element content of fossil biogenic apatite through eustatic sea level cycles shark teeth from the oligocene boom clay formation belgium have been analyzed for trace elements by neutron activation analysis to examine whether biogenic apatite might record changes in seawater trace element chemistry throughout a eustatic sequence an additional set of samples from a wide range of depositional environments has been studied to shed light on the nature of factors that govern the trace element variation of fossil apatite biogenic apatite samples from a given sedimentary basin exhibit rather specific and distinctive trace element fingerprints which shows that they reliably record geochemical parameters of the sedimentary environment it appears that sea level changes do not substantially affect geochemical processes in an epicontinental marine sedimentary basin but minor chemical changes do coincide with sequence stratigraphic levels slightly higher la yb ratios correlate with periods of higher turbulence positive ce anomalies indicate that a large fraction of the kee adsorbed by the shark teeth can be derived from the upward flux of reduced pore water this process greatly diminishes the usefulness of the ce anomaly as a palaeoredox probe a factor analysis performed on trace element data and sedimentary environment parameters suggests that ree contents ree sc and th ree ratios are related to sediment input c 1997 elsevier science b v

reworking of cretaceous dinosaurs into paleocene channel deposits upper hell creek formation montana dinosaur teeth from paleocene channel fills have been interpreted as indicating dinosaur survival into the paleocene however enormous potential for reworking exists because these records are restricted to large channel fills that are deeply incised into cretaceous strata identification of reworked fossils is usually equivocal this problem is illustrated by the black spring coulee channel fill a dinosaur bearing paleocene deposit in the upper hell creek formation of eastern montana in this example the reworked nature of well preserved dinosaur bones is apparent only after detailed sedimentological and palynological analysis because of the potential for reworking dinosaur remains derived from paleocene fluvial deposits should not be assigned a paleocene age unless they 1 are found in floodplain deposits 2 are articulated 3 are in channels that do not incise cretaceous strata or 4 are demonstrably reworked from paleocene deposits to date reports of paleocene dinosaurs do not fulfill any of these criteria thus the proposal that dinosaurs persisted into the paleocene remains unsubstantiated

lithostratigraphy tephrochronology and rare earth element geochemistry of fossils at the classical pleistocene fossil lake area south central oregon abstract one of the most famous fossiliferous pleistocene sites in the pacific northwest is fossil lake oregon until recently fossil collections from the area were not stratigraphically controlled owing to the lack of a detailed stratigraphic and chronologic framework our field studies reveal at least nine exposed thin rhythmic fining upward depositional packages most separated by disconformities analysis of interbedded tephras reveals that the rye patch dam 646 ka dibekulewe 610 ka tulelake t64 95 ka marble bluff 47 ka and trego hot springs 23 2 ka tephra layers are present in the section indicating deposition from more than 646 ka to less than 23 ka which includes both the late irvingtonian and rancholabrean north american land mammal ages a much longer time span than previously believed bones analyzed from eight of the defined units have distinctly different rare earth element ree signatures fossils obtain ree during early diagenesis and signatures are probably closely

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

direct u pb dating of cretaceous and paleocene dinosaur bones san juan basin new mexico vertebrate fossils have been important for relative dating of terrestrial rocks for decades but direct dating of these fossils has heretofore been unsuccessful in this study we employ recent advances in laser ablation in situ u pb dating techniques to directly date two dinosaur fossils from the san juan basin of northwestern new mexico and southwestern colorado united states a cretaceous dinosaur bone collected from just below the cretaceous paleogene interface yielded a u pb date of 73 6 0 9 ma in excellent agreement with a previously determined 40 ar 39 ar date of 73 04 0 25 ma for an ash bed near this site the second dinosaur bone sample from paleocene strata just above the cretaceous paleogene interface yielded a paleocene u pb date of 64 8 0 9 ma consistent with palynologic paleomagnetic and fossil mammal biochronologic data this first successful direct dating of fossil vertebrate bone provides a new methodology with the potential to directly obtain accurate dates for any vertebrate fossil

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

trace elements in conodont phosphates from the frasnian famennian boundary abstract rare earth elements ree and th concentrations on individual devonian conodonts were measured by icp ms from stratigraphic sections across the frasnian famennian f f boundary in the montagne noire southern france and morocco the present data confirm the reversed concavity of the ree spectra found by wright et al 1986 which is a characteristic although poorly understood feature of the ancient oceanic sediments within the layers corresponding to the upper kellwasser and the f f events the ce ce ratios show only minor changes with respect to younger and older sediments the magnitude of the ce anomaly is nevertheless consistently weak over all the sections if as in modern oceans the biologically mediated ce anomaly in particles and seawater originates in the uppermost water column the present observations suggest a global decrease in the biological productivity lower productivity is supported by the decreasing abundance of conodont elements during the upper kellwasser but continuing carbonate deposition through this period still makes evidence quite equivoqual as a proxy to th pa fractionation in modern sediments the th la fractionation is a potential tracer of the rate of horizontal exchange of seawater between deep sea and continental margins which may be correlated with eustatic sea level fluctuations during the upper kellwasser crisis the th la ratios fall significantly in all the sections this can reflect reduced exchanges between the deep sea and continental margins it is suggested that the f f extinction event was the result of the coincidence between a rather modest transgression event and global suboxia

an early triassic polar predator ecosystem revealed by vertebrate coprolites from the bulgo sandstone sydney basin of southeastern australia abstract vertebrate trace fossils often provide a measure of cryptic biodiversity and are especially pertinent when skeletal remnants are exceptionally rare the lower triassic lower olenekian bulgo sandstone at long reef in the sydney basin of southeastern australia constitutes just such a deposit having yielded isolated bones of giant capitosaurian temnospondyls and proterosuchid archosauriforms together with abundant coprolites that are geochemically rich in elemental phosphate and carbon denoting vertebrate predators microstructural analysis of these preserved droppings reveals occasional bone fragments fish scales insect cuticles plant material and bacterial traces pseudomorph voids as well as silicate mineral particles ree concentrations indicate that burial and early diagenesis occurred explicitly within fluvial sediments furthermore external morphological characterization permits attribution of spiral coprolites to chondrichthyan or osteichthyan fishes polygonal ovoid spherical and typically flattened feces to temnospondyls and conspicuously large cylindrical droppings to archosauriforms or other amniote apex predators collectively the bulgo sandstone coprolite assemblage thus offers new insights into ecosystem structure and palaeoenvironment in what was an earliest triassic near polar setting such data compliments the documented skeletal record but indicates a greater range of aquatic and possibly terrestrial carnivores the latter being enigmatically sparse in the australian triassic and yet detected here via the hitherto underexplored trace fossil evidence of their ecological presence

timescales and mechanisms of ree and hf uptake in fossil bones abstract rare earth element ree patterns of fossil bones and teeth are widely used as proxies for provenance taphonomy and palaeoenvironment in order to investigate if fossil bones behave as closed systems over geologic time ree profiles were analysed by la icpms along cross sections of 54 bones from various well characterised and well dated settings these include terrestrial and marine diagenetic environments covering early triassic to holocene ages in general all fossil bones exhibit the highest ree concentrations at the outer rim gradually decreasing by up to four orders of magnitude toward the inner bone cortex intra bone ree concentration gradients decrease significantly from quaternary via tertiary to mesozoic specimens suggesting long term ree uptake and open system behaviour of fossil bone this view is further corroborated by 176lu 176hf dating of selected samples all yielding significantly younger ages than the known chronostratigraphic ages hence there is clear evidence for long term open system behaviour of fossil bones with respect to ree which is in marked contrast to currently accepted models suggesting that ree uptake is only early diagenetic although unexpected statistically significant four to seven point isochrons are observed for four fossil dinosaur bone samples and one upper triassic mastodonsaurus tooth with mswds ranging from 0 083 to 4 5 notably mobility of lu alone cannot account for the observed age patterns assuming constant lu uptake rates over time the radiometric ages should only be as low as half of the chronostratigraphic age however a six point isochron defined by subsamples of a single upper triassic mastodonsaurus tooth yields an age of 65 2 1 1 ma mswd 0 68 much younger than half of the stratigraphic age ca 234 ma hence hf must also undergo late diagenetic exchange likely mechanisms to account for the presence of statistically meaningful isochrons as well as for the late diagenetic exchange of both ree and hf are diffusion adsorption and dissolution reprecipitation processes

stable isotope composition and rare earth element content of vertebrate remains from the late cretaceous of northern spain lano did the environmental record survive abstract oxygen and carbon isotope measurements have been performed on phosphatic remains from faunal associations dinosaurs crocodiles turtles and fish of the late cretaceous continental and marine sediments from northern spain basque country the environmental meaning of the oxygen isotope record in fossil reptiles is discussed on the basis of known paleoecology modern fauna analogs and apatite chemistry rare earth elements ree co32 and po43 contents fossil remains in sandstones and argillites from two localities urria and cuezva have low down to 16 and scattered 18o po4 co3 and 13c values with ree patterns characterized by strong middle ree enrichments these geochemical compositions of the biogenic apatites have most likely been acquired during a multi stage late diagenesis involving complete recrystallization of the apatite in the presence of aqueous fluids ree contents of fossils preserved in the clayey sands from the site of lano suggest that samples have only been affected by early diagenesis despite the diversity of analyzed taxa and the close association of marine sharks and rays and freshwater species crocodiles and turtles evolving in a littoral environment the narrow range of phosphate 18o values is interpreted as reflecting the temperature and isotopic composition of groundwaters that prevailed in the burial environment the potential information relative to the physiology and thermal regime of the vertebrates has been erased during the process of early diagenesis if all oxygen in the phosphate has exchanged with groundwaters the oxygen isotope composition of vertebrate remains suggests that a warm climate t 20 25 c prevailed in northern spain during the late cretaceous