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 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

a multi proxy geochemical investigation of the early paleocene danian continental palaeoclimate at the fontllonga 3 site south central pyrenees spain chronologically well constrained non marine deposits across the cretaceous tertiary boundary ktb are exceptionally rare the fontllonga section tremp formation south central pyrenees lleida spain constitutes one of these rare global records stable isotope 18oco3 and 13c analyses have been performed on the carbonate fraction of 29 samples from diverse skeletal micro remains charophyte gyrogonites gastropod shells ostracod valves and isolated skeletal remains of lepisosteids and pycnodonts from the earliest danian site fontllonga 3 a mean ba ca water palaeotemperature of 28 0 6 7 c has been obtained from the ganoine of 25 lepisosteid scales this mean palaeotemperature is comparable with the temperature tolerance range for extant relatives of fossil osteoglossiform fish found at fontllonga 3 which require a temperature range of 24 35 c mean annual temperature 27 30 c to survive using the temperature range provided by the ba ca palaeothermometer 21 3 34 7 c it is possible to determine 18owater values from the isotopic content of charophyte gyrogonites gastropod shells ostracod valves and fish remains mean 18oco3 5 00 0 21 18owater values of between 4 01 and 0 95 vsmow are calculated which when combined with la yb n versus la sm n plots are in good agreement with the sedimentary interpretation of the site as an estuarine environment based upon a comparison with modern day meteorical conditions these isotopic values are relatively high for subtropical freshwaters suggesting a low precipitation rate amount effect high evaporation rate and or long residence time when combined with other isotopic palaeobotanical and mineralogical studies carried out in the pyrenean and tethys realms this first geochemical study of an early paleocene site is consistent with there being a subtropical seasonally dry climate in the south central pyrenees at this time

identification of primary ce anomaly signatures in fossil biogenic apatite implication for the cambrian oceanic anoxia and phosphogenesis based on ree analyses of 105 world wide distributed cambrian fossil apatite samples and eight late neoproterozoic phosphate concretions a close relationship is established between the concentrations of mree and ce anomalies shale la smn ratios of 0 35 is suggested as a critical value for the discrimination of the natural ce anomaly acquired during pre burial early diagenesis by biogenic apatite from an artificial ce anomaly induced due to the calculation ce anomalies in apatites with flat ree distribution and la smn ratio 0 35 may be used as indicative of oceanic anoxia

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

crystallinity and diagenesis of sedimentary apatites the crystallinity of sedimentary apatites was determined by fourier transform infrared spectroscopy ft ir using the splitting of a triply degenerate antisymmetric bending vibration of orthophosphate the crystallinity indices of recent marine apatites are low 3 0 3 6 while those of onland ancient apatites are high 4 5 7 8 indicating post depositional recrystallization the infrared spectra reveal that recrystallization is associated with a decrease in carbonate content substituting for po43 and an increase in fluoride order within the apatite structure the relationship between the crystallinity index and po43 18o suggests alteration of the primary isotopic composition by exchange reactions between po43 oxygens and surrounding waters the monterey samples have a large range of crystallinity index that reflects a set of complex and highly variable diagenetic conditions this demonstrates the use of ft ir criteria for differentiating between pristine and altered apatites and as a consequence for relating geochemical markers to formation or diagenetic environments it is suggested that only those samples that have low crystallinity indices c i 3 8 should be considered as pristine apatite spectra of fish remains indicate that differences in rare earth element ree patterns correspond to variations in crystallinity carbonate content and f order in the apatite lattice the fact that crystallinity is not correlated with geologic age suggests that environmental factors such as accumulation rate and pore water chemistry govern the recrystallization process in general sr content decreases and 18op exhibits high variability with increasing crystallinity

the environment of deposition indicated by the distribution of rare earth elements in fossil bones from olduvai gorge tanzania fossil bones of pleistocene age from olduvai gorge tanzania incorporated relatively high concentrations up to several thousands ppm of rare earth elements during their fossilization the data indicate that these elements were mobile during the diagenetic processes involved in the fossilization of the bones it is suggested that the high concentrations arose through interaction of the bone with groundwaters enriched in these and other elements introduced by contemporaneous carbonatitic or alkalic volcanism the distributions of the rare earth elements within both the fossil bone and enclosing sediment are heterogeneous but spatially systematic with concentration profiles showing a maximum in the bone at its sediment interface despite the relative porous nature of bone the steepness and variability of the rare earth element profiles indicate chemical equilibrium has not been reached of the individual rare earth elements ce behaved differently from the others systematic variations in and magnitudes of the ce anomaly within the bone cortices from different depositional environments indicate that the redox potential of the environment during fossilization was the principal factor affecting the distribution of this element

effects of diagenesis on strontium carbon nitrogen and oxygen concentration and isotopic composition of bone abstract paleodietary analysis based on variations in the trace element and stable isotopic composition of inorganic and organic phases in fossil bone depends on the assumption that measured values reflect in vivo values to test for postmortem alteration we measured 87 sr 86 sr 13 c 12 c 18 o 16 o and 15 n 14 n ratios and sr concentrations in modern and prehistoric 610 to 5470 yr old bones of animals with marine or terrestrial diets from greenland bones from modern terrestrial feeders have substantially lower sr concentrations and more radiogenic 87 sr 86 sr ratios than those from modern marine feeders this contrast was not preserved in the prehistoric samples which showed almost complete overlap for both sr concentration and isotopic composition in bones from the two types of animals leaching experiments x ray diffraction analysis and infrared spectroscopy indicate that alteration of the sr concentration and isotopic composition in prehistoric bone probably results from nearly complete exchange with groundwater oxygen isotope ratios in fossil apatite carbonate also failed to preserve the original discrimination between modern terrestrial and marine feeders the c isotope ratio of apatite carbonate did not discriminate between animals with marine or terrestrial diets in the modern samples even so the ranges of apatite 13 c values in prehistoric bone are more scattered than in modern samples for both groups suggesting alteration had occurred 13 c and 15 n values of collagen in modern bone are distinctly different for the two feeding types and this distinction is preserved in most of the prehistoric samples our results suggest that postmortem alteration of dietary tracers in the inorganic phases of bone may be a problem at all archaeological sites and must be evaluated in each case while collagen analyzed in this study was resistant to alteration evaluation of the possibility of diagenetic alteration of its isotopic composition in bones from other contexts is also warranted

rare earth element geochemistry of laminated diatom mats from tropical west pacific evidence for more reducing bottomwaters and higher primary productivity during the last glacial maximum rare earth elements ree along with selected major and trace elements were measured in laminated ethmodiscus rex diatom mats and associated sediments diatomaceous clay and pelagic clay in two sediment cores collected from the parece vela basin of the eastern philippine sea ree distributions are characterized by strong enrichment of middle ree mree and heavy ree hree over light ree lree and slight enrichment of mree over hree this distribution pattern suggests that ree compositions of the laminated e rex diatom mats were not the product of e rex blooms an inference also supported by the fact that ti normalized ree concentrations are not clearly different from those in the diatomaceous clay and pelagic clay comparison of ree patterns with the vertical distribution of authigenic phases in the sediment indicates that lree were dominantly associated with detrital materials whereas mree and hree were selectively enriched by mn oxyhydroxides and authigenic phosphates in the pelagic clay a weak negative ce anomaly cannot be linked to oxic depositional conditions but instead is attributed to the retention of a negative ce anomaly associated with authigenic phosphates in the laminated e rex diatom mats a weak positive ce anomaly is consistent with depositional sulfidic anoxic conditions and is interpreted to represent enhanced scavenging of reduced aqueous ce3 by barite in a strongly reducing environment moreover variably negative to positive ce anomalies in the diatomaceous clay may reflect the concurrent operation of the two processes controlling ce accumulation in the laminated e rex diatom mats and pelagic clay the study cores show a ubiquitous positive eu anomaly owing to the presence of volcanic materials the smaller eu anomaly in the laminated e rex diatom mats and diatomaceous clay relative to that in the pelagic clay may be attributed to the release of reduced eu2 from mineral phases to the sediment pore water under strongly reducing conditions previous studies have shown that the advection of lower circumpolar water lcpw strengthened during the last glacial maximum lgm which should have resulted in better ventilation of the deep eastern philippine sea evidence presented here for more reducing bottomwater conditions during the laminated e rex diatom mats formation implicates elevated primary productivity and enhanced organic sinking fluxes as primary controls on redox changes in the eastern philippine sea during the lgm enhanced primary productivity and more reducing bottomwaters during the laminated e rex diatom mats deposition resulted in a larger respired carbon pool in the deep eastern philippine sea which may have been part of a larger scale modulation of atmospheric co2 variation during pleistocene glacial interglacial cycles by deep ocean carbon storage c 2011 elsevier b v all rights reserved

palaeoenvironments of the late triassic rhaetian sea implications from oxygen and strontium isotopes of hybodont shark teeth the oxygen and strontium isotopic composition of 125 teeth of the hybodont sharks lissodus and hybodus from various late triassic rhaetian bone bed localities in the central european basin are used as environmental and ecological tracers for the shallow epicontinental rhaetian sea the preservation of tooth enameloid was ascertained by cathodoluminescence microscopy mean 18op values differ regionally across the rhaetian sea with values of 18 6 0 6 near the western gate 16 1 0 8 in the east 15 4 0 6 in the southeast and 17 7 0 9 in the south the 18op values in the eastern rhaetian sea are 4 5 lower relative to tethyan seawater while teeth from the southern and western parts close to the marine gates are less fractionated the strontium isotopic composition of teeth from most localities is more radiogenic in comparison to late triassic seawater the observed spatial 18op trend in the rhaetian sea indicates a shift from marine to brackish conditions in the south and west towards extensively brackish conditions with salinities of less than 16 in the east thus confirming the existence of two marine gates brackish conditions persisted throughout early rhaetian times and were maintained by increased fluvial discharge from the vindelician bohemian and fennoscandian highs as a result of enhanced atmospheric moisture availability in the course of the rhaetian transgression the 18op values of lissodus and hybodus indicate euryhaline behaviour of rhaetian hybodonts by exceeding modern shark intraspecific variability the lack of accordance in 18op values between different isotopically conspicuous localities in the rhaetian sea contradicts a basin wide migration pattern differences between co site taxa might indicate some degree of niche partitioning

redbeds from the middle muschelkalk middle triassic of the sw germanic basin arid environments from pangea s interior the facies of a redbed succession from the lower middle muschelkalk of the sw germanic basin allows reconstruction of the depositional environment and inference with regard to the climate in a little studied part of pangea s interior the redbeds are dominated by fine grained terrigenous deposits with both intercalated thin sandstone and carbonate beds the clastics were derived from the nearby hinterland and their facies suggest episodic deposition on a playa mud flat or flood plain the occurrence in the lower part of the succession of sand patch breccias ooids and dolomicrite beds suggests an origin in saline pans and playa lakes these diverse facies and phreatic dolomites reflect an arid climate during deposition

development of a positive eu anomaly during diagenesis diagenetic remobilization of eu is possible under conditions of reduction to eu2 at low oxidation potential and near neutral solution producing pore waters relatively enriched in eu2 as distinct from its trivalent ree neighbours eu is reprecipitated in the 3 state in environments of high oxidation potential these processes have produced positive eu anomalies in highly oxidized pleistocene muds of the amazon deep sea fan similar occurrences should be rare but where found they do provide valuable information on local diagenetic processes and conditions

rare earth element systematics of fossil bone revealed by la icpms analysis intra bone rare earth element ree fractionation trends were studied by la icpms analysis to put constraints on 1 the mechanisms controlling ree fractionation within fossil bones 2 the relative timing of ree uptake in various parts of fossil bone and 3 the origin of ree in fossil bones we have evaluated ree bone profiles across 54 fossil bones from a broad range of well characterised taphonomic settings ranging in age from triassic to early medieval ree patterns and concentration gradients are highly variable and intra bone fractionation trends in la yb n vs la sm n space of few specimens cover almost the entire range previously observed for bulk samples intra bone variability of ce anomalies as well as variable y ho and la la n is also observed sometimes diagenetic fluids with fractionated hree enriched compositions have entered the bone from the marrow cavity producing secondary ree uptake profiles theoretical intra bone fractionation trends modelled using lattice strain theory concur with most ree data but some trends cannot be modelled using realistic boundary conditions this fact as well as the occurence of positive and negative ce anomalies within the same fossil sample hint towards changing ree compositions of diagenetic fluids over the timescales of ree uptake because apparent ce anomalies frequently evolve over bone profiles and ce anomalies can be inherited from previous fractionation events ce anomalies are a highly ambiguous tracer for constraining ambient redox conditions in general bioapatite ree signatures may not always reliably reflect ambient taphonomic or redox conditions and diagenetic fluid compositions therefore ree patterns and ce anomalies of fossil bones must be interpreted cautiously as they vary spatially within skeletal remains and are affected by intra bone fractionation processes as well as changing compositions of the diagenetic fluid

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 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

isotopic composition of recent shark teeth as a proxy for environmental conditions abstract the o c and sr isotope compositions of teeth from ten species belonging to five families and three orders of sharks were measured to determine the influence of habitat diet and possible species specific fractionation effects on the isotopic composition of biogenic phosphate from fish the sharks were recently caught in subtropical waters off the kwazulu natal kzn coast of south africa as well as from cold waters in prince william sound pws alaska and victor bay vb nunavut canada 18 o values of tooth phosphate 18 o p range from 20 9 to 23 5 for the kzn sharks for most species the range in measured 18 o p values is about 0 6 but it may be as high as 1 1 for different teeth from a single shark dentine and enameloid within individual teeth have no apparent differences in 18 o p values the 18 o p values of the kzn shark teeth reflect the typical habitat of the studied species primarily the thermal structure of the water column off kzn at depths between 20 and 280 m the 18 o p values of teeth from different greenland sharks from vb and pacific sleeper sharks from pws are very homogeneous averaging 25 8 and 24 7 respectively these values appear to be in equilibrium with deep 500 m ocean waters in each case at temperatures of about 0 3 c or less there is little discernable evidence for species specific fractionation effects for the oxygen isotope composition of phosphate in the studied marine fish the oxygen isotope composition of carbonate in apatite averages about 9 1 higher than corresponding 18 o p values in agreement with equilibrium fractionation between carbonate and phosphate but with a large variance 1 1 5 18 o c values also vary by up to 1 between enameloid and dentine within single teeth but in a non systematic way differences in 13 c values between carbonate in enameloid and dentine is also large up to 8 but the 13 c values vary systematically enameloid is always enriched in 13 c compared to dentine and the 13 c content increases with developmental stage of the teeth 13 c values measured for enameloid 1 6 to 4 8 appear to approach equilibrium with dissolved inorganic carbon in seawater in contrast 13 c values for dentine range from 6 4 to 2 3 for kzn sharks and 9 0 to 10 8 for the cold water sleeper sharks and are compatible with a predominantly dietary carbon source the 87 sr 86 sr ratios of teeth from kzn sharks as well as those from pws and vb are uniform averaging 0 709167 sr content varies from 1270 to 2100 ppm a range that is similar to that in well preserved fossilized teeth seawater sr is thus clearly incorporated in vivo concentrations of sm and nd are in the ppb range and contrast the ppm range in fossilized teeth indicating a postmortem incorporation of rare earth elements in apatite of the teeth

compilation and time series analysis of a marine carbonate δ18o δ13c 87sr 86sr and δ34s database through earth history abstract the sr s o and c isotope database of marine carbonates contains over 55 000 published isotope values of low mg calcite from diagenetically little altered phanerozoic fossil shells as well as samples of whole rocks and calcite cements of ordovician to archean age carbon and oxygen isotope data for the shell material are divided into habitat subsets high mid low latitude and deep sea and whole rock data are separated by mineralogy into calcite dolomite subsets trend correlation wavelet and spectral analyses on gaussian filtered isotope records were applied to detect and quantify similarities and patterns in temporal records with the following results 1 oxygen isotope trends from the high latitude and deep sea habitats are almost indistinguishable through the last 115 ma consistent with the existence of the oceanic conveyor belt throughout this interval 2 all oxygen isotope habitat records show a strong coherent 30 45 ma 38 ma cyclicity throughout the cretaceous and the cenozoic 3 up to 70 of the multi million year variability in the 18o record of the last 115 ma can be simulated by the following equation 18 o 0 64 sin 2 t 120 ma 0 9 x sin 2 t 38 3 ma 1 1 with x ranging from 0 4 0 6 for the low high latitude and deep sea habitats to 0 8 for the mid latitude realm 1 a 120 20 ma cycle occurs in the paleozoic and neoproterozoic 18o record consistent with paleoclimate variability as interpreted from sedimentological and faunal records 2 the offset of 13c values between deep water and high latitude vs surficial habitats at lower latitudes is consistent with the operation of a biological pump in the oceans since at least the cretaceous 3 sr and s isotope records exhibit a 60 70 ma cyclicity throughout the phanerozoic

diagenetic constraints on the use of cerium anomalies as palaeoseawater redox proxies an isotopic and ree study of cambrian phosphorites seawater rare earth element ree distributions show heavy ree enrichment and cerium depletion but these characteristics are only rarely found in ancient marine authigenic minerals such as carbonate fluorapatite and calcite this enigma may be due to changing ree distributions in seawater through time or to post depositional redistribution of ree differentiating between these two factors is however far from straightforward as their relative importance is likely to vary and evidence is often ambiguous in this article we present ree as well as strontium and sulphur isotope data for basal cambrian phosphorites of south china which confirm the emerging rule of thumb that granular phosphorites seldom reveal extreme departures from the seawater norm and tend to undergo therefore less diagenetic alteration of ree spectra than skeletal apatites and other phosphate types this study reveals stratigraphic trends in ce anomalies ce ce that could be taken to imply the preservation of a palaeoenvironmental signal however further investigation of our data shows that such trends in phosphorites can also be caused by post depositional alteration which tends to 1 increase ree contents 2 reverse ce depletion 3 alter eu anomalies and 4 concentrate preferentially the middle ree mree further alteration which may be due to weathering has led to hree depletion and positive la and y anomalies tetrad effect this is the first study where ceanom and phosphate bound sulphate s isotope values could be compared for one particular stratigraphic section which provides us with an additional tool for the interpretation of diagenetic redox conditions least altered phosphorites from meishucun that yield a strongly negative ceanom constrain early cambrian seawater 34s to about 33 we conclude that phosphorite ceanom primarily records variations in the local conditions of diagenesis while outlining some special cases in which diagenetic redox conditions may broadly reflect local bottom water redox conditions

tracing element sources of hydrothermal mineral deposits ree and y distribution and sr nd pb isotopes in fluorite from mvt deposits in the pennine orefield england fluorite from mississippi valley type mvt deposits in the south pennine orefield england displays significantly different distributions of rare earths and yttrium rey compared to fluorite from similar mvt deposits in the north pennine orefield samples from the south pennine orefield display negative ce and positive gd and y anomalies but lack any eu anomaly indicating that the rey were mobilized from relatively pure marine sedimentary carbonates in marked contrast fluorite from the north pennine orefield lacks any ce and gd anomalies but shows a pronounced positive eu anomaly suggesting that the rey were provided by different source rock s that the mineralizing hydrothermal fluid had experienced higher temperatures prior to fluorite precipitation and that it was derived from deeper crustal levels in the north compared to the south the isotopic composition of sr in blue john fluorite from the south pennine orefield suggests that sr was mobilized from lower carboniferous tournaisian limestones whereas pb isotopes suggest that in contrast to rey and sr pb was derived from aluminosilicate rocks neither nd nor sr or pb isotopes can be used to radiometrically date the formation of blue john fluorite all isotope systems studied indicate that the limestone host rock of this fluorite mineralization did not contribute to the trace element budget of the hydrothermal fluid our results show that different solutes in a natural water hydrothermal fluid groundwater etc may be derived from different sources and that the study of a small set of elements or isotope ratios may not provide full insight into the genesis or history of a mineralization or a hydrothermal fluid our data provide evidence for the uncoupling of sr nd and pb during fluid rock interaction and fluid migration and show that the use of plots such as 87sr 86sr vs end to learn about mixing relationships as is commonly done in igneous geochemistry is unreliable when applied to natural waters and their precipitates

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

temporal variations in the fractionation of the rare earth elements in a boreal river the role of colloidal particles rare earth element ree data from weekly sampling of the filtered 0 45 m and suspended particulate phase during 18 months in the kalix river northern sweden are presented together with data on colloidal particles and the solution fraction 3 kda the filtered ree concentration show large seasonal and temporal variations in the river lanthanum varied between approximately 300 and 2100 pm high ree concentration in the filter passing fraction is related to increased water discharge and there is a strong correlation between the ree concentration organic carbon al and fe physical erosion of detrital particles plays a minor role for the yearly transport of particulate ree in this boreal river system the suspended particulate fraction which is dominated by non detrital fractions accounted for only 35 of the yearly total transport of la in the river approximately 10 of the ree were transported in detrital particles during winter at spring flood in may about 30 of the lree and up to 60 of the hree where hosted in detrital particles ultrafiltration of river water during spring flood shows that colloidal particles dominate the transport of filter passing ree less than 5 of the filtered ree are found in the fraction smaller than 3 kda the colloidal fraction shows a flat to slightly lree enriched pattern whereas the solution fraction 3 kda show an hree enriched pattern compared with till in the catchment suspended particles show a lree enriched pattern data indicate that the ree are associated with two phases in the colloidal and particulate fraction an organic rich phase with associated al fe and an fe rich fe oxyhydroxide inorganic phase the ce anomaly in the suspended particulate fraction in the river shows systematic variations and can be used to interpret fractionation processes of the ree during weathering and transport there was no anomaly at maximum spring flood but during the ice covered period the anomaly became more and more negative the temporal and seasonal variations of the ce anomaly in the suspended particulate phase reflect transport of ree c al fe enriched colloids from the upper section of the till and or from mires to the river at storm events

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

ree systematics in hydrothermal fluorite abstract ree patterns of fluorite from 63 post variscan hydrothermal veins of the schwarzwald area germany can be divided into two major groups type a fluorite shows roof shaped paas normalized patterns with enriched mree the turning point of the curvature is at ho or er position all patterns of type a show a distinct positive eu anomaly type b fluorite shows roof shaped patterns with enriched mree and strongly depleted hree and a characteristic steep slope between nd and sm the turning point of the curvature is at gd to dy all patterns of type b show negative or no eu anomalies laser ablation icp ms traverses through single grains combined with cathodoluminescence imagery revealed either i identical ree patterns and total ree concentrations from core to rim ii identical ree patterns but concentration gradients or iii variable ree patterns and concentration gradients from core to rim these features are explained by different degrees of supersaturation or different fluid fluorite ratios during crystallization and by complexly controlled precipitation processes under closed system conditions petrographically late fluorites from several deposits show the characteristics of new fluid batches rather than the expected remobilization features lree enrichment close to the crystal faces in some grains may result from the copreciptiation of a submicrometer sized lree enriched phase or from lree clustering in late cool fluids by comparison with literature data on natural waters from gneissic and granitic aquifers and of leachates of granites and gneisses we show that the hydrothermal vein fluorite preserves the characteristic source related ree feature of the hydrothermal fluid that migrated through either gneissic type a or granitic type b host rocks the immediate host rocks of the veins however are not the source rocks of the ree which indicates large scale fluid convection in the basement gneiss related type a fluorite shows tb ca tb la trends of primary hydrothermal crystallization whereas granite related type b fluorite indicates remobilization of possibly pegmatitic or variscan fluorite

variations in ce anomalies of conodonts through the frasnian famennian boundary of poland kowala holy cross mountains implications for the redox state of seawater and biodiversity abstract rare earth element ree concentrations on upper devonian conodonts distinguished by very low color alteration index were measured by inductively coupled plasma mass spectrometry from a stratigraphic section across the frasnian famennian f f boundary in the holy cross mountains poland the present data show a hat shaped pattern of the ree spectra similarly to other devonian conodont spectra already documented however our sample composition suggests little to moderate alteration of the original oceanic pattern through the adsorption mechanism in a context of weak or early diagenesis all along the section the magnitude of the ce anomaly is always negative and there is an inverse correlation between the ce anomaly and the la sm sn ratio this has been interpreted as an la enrichment due to a terrestrial input a mathematical procedure was used in order to restore the original ce anomalies that would reflect the seawater environment not contaminated by terrestrial inputs no noticeable change is observed in the frasnian with homogeneous values of ce model but a sharp increase is initiated just below the f f boundary with maximum values in the lowermost famennian the measured la sm sn ratios co vary with the ce model in agreement with the hypothesis of a terrigenous input finally the inverse correlation between the values of ce model and the relative abundance of palmatolepis during the famennian constitutes the first evidence known of a redox control on the presence of a conodont genus that is an indicator of deep water environment

paleoredox variations in ancient oceans recorded by rare earth elements in fossil apatite abstract rare earth element concentrations in biogenic apatite of conodonts fish debris and inarticulate brachiopods were determined in over 200 samples from cambrian to modern sediments tests for experimental bias caused by the chemicals used to separate fossils from the rock matrix and for interlaboratory interexperiment or interspecies related variations clearly show that no resolvable fractionation of ree occurs incorporation of ree in biogenic apatite of recent fish debris occurs near the sediment water interface soon after deposition and reflects characteristics of seawater the original ree signature apparently survives subsequent burial and diagenesis cerium variations in fish debris from modern environments are controlled by redox potential ce is fractionated by co precipitation with metallic oxides under oxidizing conditions this fractionation produces a negative ce anomaly ce anom in seawater that is reflected in the sedimented fish debris conversely no fractionation of ce occurs under reducing conditions resulting in ce concentrations that are normal to enriched in anoxic seawater and fish debris deposited under local or basinwide anoxic conditions extrapolation of observations of the redox control of ce anom in modern oceans to fossil apatite indicates that anoxic conditions were prevalent in lower paleozoic and lower triassic oceans whereas in the upper paleozoic the world ocean was generally oxidizing

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

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

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

quantification of diagenesis in cenozoic sharks elemental and mineralogical changes abstract diagenesis of bone during fossilization is pervasive however the extent of this process varies with depositional environment this study quantifies diagenesis of shark vertebral centra through analysis of a suite of physical and chemical characters including crystallinty index ci carbonate content and elemental concentrations although shark skeletons are initially cartilaginous the soft cartilage of the vertebral centra is replaced with carbonate hydroxyapatite during growth nine vertebral centra are analyzed from lamnoid lamnoidea sharks ranging in age from the cretaceous to recent using fourier transform infrared spectroscopy ft ir and inductively coupled plasma mass spectrometry icpms the variables ci carbonate content rare earth element ree concentrations ca p ba ca sr ba la yb n la y n la yb n vs la sm n la yb and ce anomalies elucidate the diagenetic and depositional environments of the seven fossil vertebral centra the two extant centra demonstrate the initial unaltered end member conditions for these variables two fossil vertebral centra carcharodon megalodon and isurus hastalis demonstrate a strong terrestrial influence during diagenesis distinctive flattening of shale normalized ree patterns that masked the seawater signal three centra carcharodon auriculatus carcharodon angustidens and creotxyrhina mantelli have indications of some terrestrial influx evident by some flattening of the ree patterns relative to seawater the terrestrial influence in these five shark centra c megalodon i hastalis c auriculatus c angustidens and c mantelli are interpreted to represent a primarily nearshore habitat for these species in contrast the two otodus obliquus centra have ree patterns that represent the original seawater signal and have no indications of terrigenous input these results indicate that fossil shark vertebral centra have the potential to understand diagenesis and reconstruct paleooceanographic environments

a sandy tidal coast in the uppermost muschelkalk and the origin of the muschelkalk keuper boundary in the southwestern germanic basin a tidal coast is documented in mixed siliciclastic and carbonate sands of the uppermost muschelkalk middle triassic along the southwestern margin of the germanic basin in luxembourg the coastal sediments are vertically and laterally stacked channel fills interpreted to have formed in a tidal flat environment the channel fills overlie carbonates of a shallow subtidal ramp the strong progradation of the tidal flat indicates deposition during a late stage of sea level highstand but before sea level fall in their upper part the channel fills are overprinted by a thick paleosol which resulted from subaerial exposure around the time of the muschelkalk keuper boundary the exposure and formation of the paleosol in the subtidal coastal sediments and in basinward sections the deposition of dolomicrites above the muschelkalk keuper boundary in the lowermost keuper both indicate a sea level fall

rare earth elements and stable isotope geochemistry δ13c and δ18o of phosphorite deposits in the gafsa basin tunisia rare earth elements ree and stable isotope compositions 13c and 18o of shark teeth and phosphatic coprolites were analyzed from the lower maastrichtian layers of the el haria formation and two sequences of the paleocene eocene p e chouabine formation in the gafsa basin south western of tunisia in order to trace the sedimentological climatic and oceanographic conditions the ree chemistry and their distribution in the two archives are the same for each of the studied layers indicating that the coprolites and shark teeth experienced the same early diagenetic environments however major differences occur between the maastrichtian and the p e reflecting changes in the depositional conditions the early maastrichtian burial environment tended to be more anoxic with ree derived from reduced feo while in the p e the ree patterns mimic the modern oxic suboxic seawater the ree source from remineralisation of organic coating could have more significance the oxygen isotope compositions of the structural phosphates 18opo4 indicate a stable and warm climate during both studied time intervals a small offset 0 4 in the 18o value between the coprolites and shark teeth show minor thermal gradient between bottom and surface water the pronounced negative shift of 3 4 in 13c values recorded in the upper part of the chouabine formation was ascribed to the paleocene eocene boundary at the same time the lack of negative change in the 18o is explained by the semi closed situation of the gafsa basin which situation also played an important role in the evolution of the organic matters in the sediment resulting in the exceptional low 13c values

dissolution methods for strontium isotope stratigraphy guidelines for the use of bulk carbonate and phosphorite rocks diverse carbonate dissolution methods have been applied to bulk carbonate rocks in order to target least altered components for strontium isotope stratigraphy sis this is especially important for precambrian and cambrian studies for which no suitable skeletal material is available one proven method for bulk limestones involves the removal of up to a third of the powdered sample using an acid pre leach before partial dissolution of the rest of the sample using a weak acid or acid buffer solution we applied a similar technique to dissolve a range of lithologies limestone dolostone and phosphorite and compared the strontium isotopic composition of various leaches to contemporaneous seawater our results vindicate this approach and allow us to conclude that some dolomitic and phosphatic rock components may retain a near primary seawater 87sr 86sr composition once contaminant strontium from secondary calcite and other phases has been removed commonly applied trace element e g mn sr mg ca and isotopic c o screening cut offs were also examined in the light of these results and proved unreliable particularly in the case of dolostones and partially dolomitized limestones we recommend that rigid sample selection and sequential leaching procedures be applied to all sis studies of bulk materials and propose a general protocol for strontium isotope studies on marine authigenic rocks which may also be applicable to rare earth element and other geochemical studies of marine authigenic minerals in the future

identification of sources affecting water chemistry in the nakdong river south korea the sources impacting the water chemistry of the nakdong river nr in south korea were investigated in order to examine the pollution mechanism including the fate and transport of the contaminants and how much such sources may affect its main channel of water resource water samples were collected between 2007 and 2008 from 8 sites along a 510 km downstream transect of the nr and chemical and isotopic compositions of the water samples were evaluated to identify natural and anthropogenic sources contributing to the water chemistry of the nr the results showed that the major ion concentrations were mainly controlled by chemical weathering that occurred in the watershed in which a silicate weathering is more dominant than a carbonate weathering the 87sr 86sr ratios of the water samples were in a range from 0 71043 to 0 71520 within those of the mesozoic volcanogenic sedimentary rocks long developed in the watershed thereby supporting the fact that the water chemistry is governed by a chemical weathering the 34s values varied in a narrow range of 1 8 3 1 regardless of spatial and seasonal variations mass balance calculations indicated that the contributions of chemical weathering and anthropogenic sources during summer time increased along a downstream transect from 67 3 1 3 to 73 6 0 5 and from 6 0 to 15 7 respectively in contrast the contribution of chemical weathering during winter time decreased from 82 7 0 8 to 72 5 0 3 while anthropogenic contribution increased up to 22 2 these results indicated that the water chemistry of the nr was mainly caused by a chemical weathering followed by anthropogenic inputs and rainwater this study will provide baseline information for comparing the water quality issue before and after the implementation of the four rivers restoration project of south korea

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

comparing the performance of a 2 d finite element and a 2 d finite volume model of floodplain inundation using airborne sar imagery the performances of a finite volume model sfv and finite element model telemac 2d in reproducing inundation on a 16 km reach of the river severn united kingdom are compared predicted inundation extents are compared with 4 airborne synthetic aperture radar images of a major flood event in november 2000 and these are used to calibrate 2 values of manning s n for the channel and floodplain the four images are shown to have different capacities to constrain roughness parameters with the image acquired at low flow rate doing better in determining these parameters than the image acquired at approximately peak flow this is assigned to the valley filling nature of the flood and the associated insensitivity of flood extent to changes in water level the level of skill demonstrated by the models when compared with inundation derived using a horizontal water free surface also increases as flow rate drops the two models show markedly different behaviours to the calibration process with telemac showing less sensitivity and lower optimum values for manning s n than sfv when the models are used in predictive mode calibrated against one image and predicting another sfv performs better than telemac copyright 2007 john wiley sons ltd

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

sequence stratigraphy of middle triassic carbonates and terrigenous deposits muschelkalk and lower keuper in the sw germanic basin maximum flooding versus maximum depth in intracratonic basins abstract we analyze the sequence stratigraphy of the middle muschelkalk to the lower keuper strata middle triassic in the sw germanic basin the sequences are interpreted on the basis of a synthesis of facies in the neritic carbonates terrigenous sediments and evaporites along a basin margin to center transect continental sediments cs lower middle muschelkalk occur at the base of the middle upper muschelkalk sequence thick retrogradational marginal marine sediments overlain by open marine deposits middle middle muschelkalk to lower upper muschelkalk form the transgressive systems tract in the basin center only bathymetric criteria are available for recognition of this systems tract the maximum flooding surface mfs at the basin margin differs in age from the maximum depth interval in the basin center maximum depth surfaces or intervals mdi new term should be recognized in many deep basins where flooding is not recorded the highstand systems tract upper upper muschelkalk is strongly progradational the upper sequence boundary muschelkalk keuper boundary is characterized by subaerial exposure at the basin margin and submarine erosion in most other sections along this boundary the low paleo relief resulted in a lack of coarse grained clastic deposits in the basin center a strongly regressive succession lower lower keuper allows possibly for the first time in an intracratonic basin the distinction of an early or late lowstand systems tract elst or llst high frequency low amplitude sea level fluctuations resulted in parasequences in the open marine upper muschelkalk but in high frequency sequences in the coastal plain sediments of the overlying parts of the lower keuper

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

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

lower triassic sequence stratigraphy of the western part of the germanic basin west of black forest fluvial system evolution through time and space abstract the aim of this paper is to analyse the fluvial evolution of the lower triassic in the western part of the germanic basin through time and space as well as the impact of the geodynamic and climatic setting on the preservation of fluvial deposits the lower triassic crops out only in the vosges massif and the black forest so well log studies are required to realise sequence stratigraphy correlations and establish comparisons with others parts of the germanic basin in a first step we use well log data analyses to characterise the electrofacies associations in the triassic and then define the well log signatures of each formation in a second step the characterisation and recognition of genetic sequences and their stacking pattern allow us to define seven minor cycles integrated into two major cycles finally the quantification of the lithologies at different stages of basin evolution leads to the reconstruction of paleoenvironmental maps to illustrate facies evolution through space and time a comparison with cycles defined in the germanic basin allows us to propose correlations of the lower triassic on either side of the rhine graben and leads to a discussion of the evolution of fluvial systems through time and space during the scythian the fluvial style is characterised by braided fluvial systems evolving laterally into lake deposits towards the central part of the germanic basin during this stage the basin was a huge depression with very few marine connections in its extreme eastern part the stratigraphic cycles represent rhythmic fluctuations in relative lake level that could be attributed to sediment supply and or lake level variations in an arid setting four minor stratigraphic cycles are observed that are integrated within a single major stratigraphic cycle during the period of the stratigraphic base level rise of the major cycle a maximum of 233 m of sediment would represent a duration of sedimentation in the paris basin of at least 1 8 m y during the period of the stratigraphic base level fall of the major cycle a maximum of 65 m of sediment would have accumulated over 2 5 m y on the western edge of the germanic basin the top of the scythian is marked by a major sedimentary break characterised by a planation surface with preservation of the first paleosols followed by the hardegsen unconformity this unconformity is tectonically deformed leading to the development of a new sedimentation area in the west of the basin the fluvial sedimentation above this discontinuity shows a trend towards enhanced development of floodplain or lacustrine type environments at its western margin with the formation of paleosols the fluvial systems are linked with sabkhas and then with a shallow sea connected to the tethys ocean in this context the stratigraphic cycles are caused by variations in relative sea level and or sediment supply the fluvial deposits are preserved in an exoreic basin

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

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

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

a model of fossil tooth and bone diagenesis implications for paleodiet reconstruction from stable isotopes abstract diagenesis of structural carbonate in biogenic apatite in the postmortem environment is modeled as a process of water mineral interaction both closed and open system model calculations suggest that 13 c of structural carbonate in biogenic apatite is much more resistant to diagenetic modification than 18 o apatite structural carbonate retains an original 13 c signal in closed system diagenesis for open systems 13 c of biogenic apatite with very low porosity such as tooth enamel can survive most diagenesis and retain a primary isotopic signature on the hand 18 o of structural carbonate in biogenic apatite may not be a reliable indicator of the original isotopic ratios except in a diagenetic system with low temperature and very low water biomineral ratio application of the model to teeth and carbonate cement in sediments from the badlands south dakota illustrates that 13 c values of enamel samples preserve the original signal whereas 13 c values of dentine represent varying extents of diagenesis 18 o values of fossil teeth may record an early or late part of their water biomineral interaction history during diagenesis

diagenetical changes in pleistocene small mammal bones from olduvai bed i abstract fossil bones of small mammals from two levels at olduvai bed i tanzania were analysed for a range of elements using electron microprobe techniques comparison of the fossil samples is made with those of recent samples collected from close to the natron alkaline lake tanzania values for the elements na sr ba are significantly higher and s lower in the fossil samples relative to the recent samples in addition concentrations of the rare earth elements reach exceptionally high concentration levels i e 6 wt in one of the sites whereas these elements are not detected in the recent samples the high concentrations of these elements in the fossil samples are clearly a result of diagenetic alteration although the effects of digestion are likely to have had some influence on the processes involved in the incorporation of elements during fossilisation statistical analyses show there are significant differences in the chemical compositions of fossil bones from two levels in bed i observed changes in the rare earth element patterns in particular the ce anomaly suggest that relative differences in the redox potentials of the burial and depositional environments existed at the two levels fluctuations in the size and extent of the palaeolake are considered to be the likely cause of these differences

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

strontium isotopic signatures in the enameloid and dentine of upper cretaceous shark teeth from western alabama paleoecologic and geochronologic implications abstract the 87sr 86sr isotopic composition of the enameloid tips of teeth of scapanorhynchus texanus a common and widespread upper cretaceous shark differs from that found in the dentine inner portions of the same teeth using a marine 87sr 86sr isotopic evolution curve we converted the 87sr 86sr isotopic composition of different sections of the teeth to numerical ages portions of fossil teeth dominated by enameloid but that include some dentine yield numerical ages 74 2 0 8 ma 2 standard error s e that fall within the upper cretaceous and are consistent with the known geologic age range of these fossils as the proportion of dentine present in samples of the teeth increases the 87sr 86sr derived numerical ages trend from biostratigraphically reasonable upper cretaceous ages to those that are far younger and biostratigraphically impossible about 32 ma i e oligocene this deviation in isotopic composition and numerical age is likely the result of post burial diagenetic alteration of dentine which is generally more susceptible to such alteration than enameloid to avoid the contaminating effects of dentine we sampled only the enameloid portion of twelve s texanus teeth by scratching their surfaces the enameloid scratch samples yield numerical ages 78 8 0 4 ma 2 s e older than those obtained for any of the sectioned samples this suggests that sampling only the surface enameloid of shark teeth is useful in reducing spurious isotopic results arising from post burial alteration of teeth the numerical age for the enameloid scratch samples is consistent with the known early campanian early maastrichtian occurrence of s texanus in north america and with the radiometric age of the deposit from which these samples were recovered

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

trace and rare earth element geochemistry of phosphate nodules from the lower cambrian black shale sequence in the mufu mountain of nanjing jiangsu province china abstract phosphate nodules are abundant in the lowermost section of the lower cambrian black shale sequence along a ne trend belt in the yangtze platform south china in this study we examined the neoproterozoic cambrian mufu mountain section near nanjing of jiangsu province and conducted a detailed trace and rare earth element ree study on the phosphate nodules we employed a step leaching acid dissolution protocol of 1 m hac and 1 m hcl respectively to separate carbonate from phosphate mineral contributions in the nodules both the hac leached and hcl leached fractions of the phosphate nodules show similar symmetrical variations in trace and ree concentrations and ratios the total rees and a number of redox sensitive trace metals such as v cr mo ni abundances show a systematic increase from the core to rim whereas the u and mn abundances decrease from the core to rim in most of the nodules similar trends are also observed for the rb sr u th co ni and v ni ratios but these trends in the hac leached fractions are less pronounced than the hcl leached fractions all of the hcl leached fractions for the nodule cores show seawater like shale normalized ree patterns but the rims of the nodules display slightly mree enriched and hree depleted patterns we suggest that the phosphate nodules may have formed in a basinal setting beneath a stratified water column during early cambrian and the compositional variations of rees and redox sensitive trace elements from the core to rim may record a changing redox condition and fluid mixing during different stages of nodule growth the cores of the nodules preserve more pronounced negative ce anomalies and progressively hree enriched patterns which may retain primary early cambrian seawater chemistry whereas the nodule rims record chemistry consistent with changed redox conditions and or influences from pore fluids such as generated from degradation of organic matter

preservation of seawater sr and nd isotopes in fossil fish teeth bad news and good news abstract we analyzed 87sr 86sr ratios in foraminifera pore fluids and fish teeth for samples ranging in age from eocene to pleistocene from four ocean drilling program sites distributed around the globe site 1090 in the cape basin of the southern ocean site 757 on the ninetyeast ridge in the indian ocean site 807 on the ontong java plateau in the western equatorial pacific and site 689 on the maud rise in the southern ocean sr isotopic ratios for dated foraminifera consistently plot on the global seawater sr isotope curve for sites 1090 757 and 807 sr isotopic values of the pore fluids are generally less radiogenic than contemporaneous seawater values as are values for fossil fish teeth in contrast pore fluid 87sr 86sr values at site 689 are more radiogenic than contemporaneous seawater and the corresponding fish teeth also record more radiogenic values thus sr isotopic values preserved in fossil fish teeth are consistently altered in the direction of the pore fluid values furthermore there is a correlation between the magnitude of the offset between the pore fluids and the seawater curve and the associated offset between the fish teeth and the seawater curve these data suggest that the hydroxyfluorapatite of the fossil fish teeth continues to recrystallize and exchange sr with its surroundings during burial and diagenesis therefore sr chemostratigraphy can be used to determine rough ages for fossil fish teeth in these cores but cannot be used to fine tune age models in contrast to the sr isotopic system our nd concentration data combined with published isotopic and rare earth element data suggest that fish teeth acquire nd during early diagenesis while they are still in direct contact with seawater the concentrations of nd acquired at this stage are extremely high relative to the concentrations in surrounding pore fluids as a result nd isotopes are not altered during burial and later diagenesis therefore fossil fish teeth from a variety of marine environments preserve a reliable and robust record of deep seawater nd isotopic compositions from the time of deposition

rare earth geochemistry of phosphorites abstract the abundance of rare earth elements ree s in francolite increases with increasing age as a result of post depositional enrichment abundances are higher in pelletal samples than in non pelletal ones because the higher surface mass ratio of pelletal francolite promotes enrichment during diagenesis onshore francolite has higher ree abundances than that found offshore distribution patterns in francolite may be similar to those reported for open ocean water or shale depending upon the dominant source of the ree s different patterns result from weathering and deep burial diagenetic modification of the original patterns and abundances negative ce anomalies occur in francolites containing structural sulphur that is isotopically indistinguishable from seawater of the same age zero or positive anomalies occur in francolites which contain sulphur that is isotopically lighter than seawater

paleoenvironmental conditions and strontium isotope stratigraphy in the paleogene gafsa basin tunisia deduced from geochemical analyses of phosphatic fossils fossil shark teeth and coprolites from three major phosphorite occurrences in the gafsa basin southwestern tunisia were investigated for their geochemical compositions to improve local stratigraphy and to better assess paleoenvironmental conditions 87sr 86sr isotope ratios of shark teeth from the early maastrichtian el haria formation and from the early eocene metlaoui s s formation yielded sr isotope ages of 68 1 and 47 9 1 3 ma respectively which accord with the expected stratigraphic positions of these sediments conversely shark teeth from the paleocene eocene chouabine formation have large variation in sr isotope ratios even within individual layers after statistical treatment and then elimination of certain outlier samples three age models are proposed and discussed the most reasonable solution includes three subsequent sr ages of 61 8 2 2 ma 57 2 1 8 and 54 6 1 6 for layer ix layers viii v and layers iv 0 respectively three scenarios are discussed for explanation of the presence of the outliers 1 diagenesis 2 re working and 3 locally controlled seawater sr isotope ratio the most plausible account for the higher 87sr 86sr ratios relative to the global ocean in some fossils is enhanced intrabasinal re working due to low sea level conversely the sample with lower 87sr 86sr than the global seawater may link to diagenesis or to seawater influenced by weathering of late cretaceous marine carbonates which latter is supported by model calculation as well the end values of these fossils are very similar to those reported for paleogene and late cretaceous tethyan seawater and are compatible with the above interpretations the relatively low oxygen isotope values in shark teeth from the topmost phosphate bed of the chouabine formation together with the sr isotope results point toward recovering better connections with the open sea these 18o data reflect elevated ambient temperature which may link to the early eocene climatic optimum

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

strontium isotope evolution of late permian and triassic seawater the 87sr 86sr values based on brachiopods and conodonts define a nearly continuous record for the late permian and triassic intervals minor gaps in measurements exist only for the uppermost brahmanian lower part of the upper olenekian and middle norian and only sparse data are available for the late permian these 219 measurements include 67 brachiopods and 114 conodont samples from the tethyan realm as well as 37 brachiopods and one conodont sample from the mid european middle triassic muschelkalk sea the late permian lower triassic interval is characterized by a steep 1 3 10 3 rise from 0 7070 at the base of the dzhulfian to 0 7082 in the late olenekian a rate of change comparable to that in the cenozoic in the mid triassic anisian and ladinian the isotope values fall to 0 7075 followed again by a rise to 0 7081 in the middle late norian the 87sr 86sr values decline again in the late norian sevatian and rhaetian to 0 7076 the sharp rise in the 87sr 86sr values during the late permian early triassic was coincident with widespread clastic sedimentation because of the paucity of tectonic uplifts the enhanced erosion may have been due to intermittent humid phases during mainly an arid interval coupled with the absence of a dense protective land plant cover following the mass extinction during the latest permian the apex of the 87sr 86sr curve at the olenekian anisian boundary coincides with cessation of the large scale clastic sedimentation and also marks the final recovery of land vegetation as indicated by the renewed onset of coal formation in the middle triassic the rising 87sr 86sr values from the middle carnian to the late norian coincide with the uplift and erosion of the cimmeride indosinian orogens marking the closure of the palaeotethys the subsequent rhaetian decline that continues into jurassic pliensbachian toarcian boundary on the other hand coincides with the opening of the vardar ocean and its eastern continuation in the izmir ankara ophiolitic belt samples from the upper muschelkalk are more radiogenic than the global trend this may reflect separation of the basin from the open ocean due to strong meteoric influx from a large land mass in the north the germanic basin became increasing brackish up section in the north and east but because of the high evaporation rates the salt content was not much reduced in the southern and central basin where a rich but increasingly endemic marine fauna survived