deep seismic reflection profile in central europe reveals complex pattern of paleozoic and alpine accretion at the east european craton margin 1 the first deep reflection seismic profile was acquired across the teisseyre tornquist zone ttz a major european suture zone southeast of the avalonia baltica collision zone portraying different tectonic deformation styles thick versus thin skinned and phanerozoic crustal accretion episodes over a relatively short distance 240 km the overall crustal structure preserves image of the neoproterozoic passive margin setting but with a significant overprint of the repetitive tectonic convergence cadomian to alpine acting at the baltica margin in contrast to the avalonia baltica collision zone here the polygenetic crustal accretion occurring at the cratonic margin was ultimately shaped by significant strike slip faulting ttz is imaged as a narrow 10 15 km transform zone separating the thinned east european cratonic crust from the malopolska block

revisiting the rare earth elements in foraminiferal tests are the rare earth elements rees in foraminifera a valuable proxy for use in paleoceanographic and climate change studies in order to investigate this we attempted a comprehensive study of rees in planktonic and benthic foraminifera several different cleaning protocols were tested although the hydroxylamine used to clean all foraminifera in this study removes an unidentified source of ree contamination it seems to remobilize metal oxides that are otherwise unaffected in flow through dissolution the calculated ree distribution coefficients kd ree s are between 100 and 500 for both planktonic and benthic foraminifera these kds are high compared to other elements in biogenic calcite but can be explained through a general model of element incorporation during foraminiferal calcification from data taken from eight core tops in the southeast pacific we conclude that the rees in planktonic foraminifera are indeed useful as a proxy for upper ocean water mass and mixed layer biogenic productivity alternatively the rees in benthic foraminifera are useful as a proxy for carbon flux to the sea floor these proxies should be robust down core unless the sediments have undergone anoxic diagenesis which stabilizes fe carbonate thus overprinting the primary ree signature however it is clear from ree distributions in foraminiferal tests if anoxic conditions have occurred

seismic basement in poland the area of contact between precambrian and phanerozoic europe in poland has complicated structure of sedimentary cover and basement the thinnest sedimentary cover in the mazury belarus anteclize is only 0 3 1 km thick increases to 7 8 km along the east european craton margin and 9 12 km in the trans european suture zone tesz the variscan domain is characterized by a 1 to 2 km thick sedimentary cover while the carpathians are characterized by very thick sediments up to c 20 km the map of the basement depth is created by combining data from geological boreholes with a set of regional seismic refraction profiles these maps do not provide data about the basement depth in the central part of the tesz and in the carpathians therefore the data set is supplemented by 32 models from deep seismic sounding profiles and a map of a high resistivity low conductivity layer from magnetotelluric soundings identified as a basement all of these data provide knowledge about the basement depth and of p wave seismic velocities of the crystalline and consolidated type of basement for the whole area of poland finally the differentiation of the basement depth and velocity is discussed with respect to geophysical fields and the tectonic division of the area

application of the ce anomaly as a paleoredox indicator the ground rules much attention has been paid in recent years to the potential application of the ce anomaly measured in various marine phases as a paleoceanographic indicator of widespread marine anoxia in this paper we present and discuss results from recent studies of present day rare earth element ree distributions and hence ce anomaly distributions in the marine environment which are particularly pertinent to paleoceanography subsequently we review and discuss the validity of the recent literature in which ce anomalies have been employed as paleoredox indicators

the assessment of ree patterns and 143nd 144nd ratios in fish remains abstract the ree content and isotopic composition of sr and nd have been determined in fish teeth ranging in age from the trias to the present and from various localities mostly around the atlantic these measurements have been carried out on selachian and teleost remains from the same locality in togo and show no appreciable difference which suggests with the help of a mass balance calculation of the ce anomaly that diagenetic effects are not responsible for the ree enrichment of biogenic phosphates one group of fossil teeth has about 3 times the ree abundances of shale and a shale normalized pattern with a minimum at sm it is thought to reflect deposition in the open sea environment a second group has ree concentration about 10 times higher than the first group with either a regular light ree enrichment or more frequently a maximum in the middle ree both being probably indicative of deposition in estuarine or near shore conditions the shape of the ree spectra and the size of the ce anomaly can be used semi quantitatively to determine the depth of deposition the results presented here on late cretaceous eocene fish teeth samples from morocco reflect an increasing influx of deep waters with a lowla yb ratio and strong negative ce anomaly which agrees well with the evolution of sediment chemistry and microfauna associations in contrast nd is typical of the water mass in which the fish debris decayed examples of nearly isolated basins identified with nd isotopes include the south atlantic prior to the lutetian nd 13 5 the miocene persian gulf nd 3 1 and bolivia during the late cretaceous nd 12 8 togo and guinea bissau results suggest that in the south atlantic the meridional oceanic circulation had not started before 45 ma ago combination of ree and nd data suggests that the assignment of jurassic cretaceous samples measured so far to open sea water masses is still ambiguous

evaluation of the application of rare earth elements to paleoceanography anomalous departures of rare earth elements ree from similarity of chemical behaviour are most evident in a comparison of ce with its neighbors under reducing conditions ce3 acts like other ree but oxidized ce4 is adsorbed on mn fe oxyhydroxides or organic particulates and consequently the remaining solution will tend to exhibit a negative ce anomaly in addition more subtle fractionations may emphasize the light or the heavy or the middle ree a pattern of ree may be recorded by immediate diagenesis on a suitable chemical substrate such as apatite fish debris conodonts carbonate or chert this record was originally thought to reflect the paleoredox conditions of primary deposition however any such primary record may be overprinted by late diagenetic alteration early analyses of ree in conodonts from a wide range of sediments suggested a prevalence of reducing conditions no ce anomaly in pre carboniferous oceans and more common oxidation negative ce anomaly in the late paleozoic however recent research by other investigators indicates that variations in cean are more diverse in origin and in particular many are distorted to an unknown extent by late diagenesis in any case it is now clear that geological age does not show a consistent relationship to the level of the ce anomaly the ce anomaly apparently does not play any regular role in the isotopic events that accompany prominent mass extinctions further research is required to understand and thus make useful the controls on the ce anomaly

the behavior of rare earth elements in seawater precise determination of variations in the north pacific water column abstract we present new highly precise and accurate data for ten rare earth elements rees in two water column profiles and in bottom waters from three additional localities in the north pacific our results presented here and in an earlier publication indicate that the water column in the western north pacific is stratified with respect to the isotopic composition of nd as well as nd la sm nd and er la both the nd isotopic and the ree data show that ree transport is strongly influenced by horizontal advection even in the sluggish circulation of the pacific in general rees increase in concentration with depth at mid latitude they reach a maximum concentration at about 3000 m and then decrease to the bottom at high latitude heavy rees reach a maximum concentration near 3000 m whereas light rees continue to increase in concentration with depth the deep water maximum and bottom water depletion is interpreted as an advective feature resulting from the flow of a lower concentration of rees in antarctic bottom water under a higher concentration of rees in the north pacific concentrations of rees do not show a linear relationship with those of si indicating that the ree cycle is not directly coupled to that of the si cycle ree element ratios i e nd la correlate with hydrographie properties which suggests that major features of the ree patterns may be conserved during lateral transport comparison of our ree data to those in previously published reports on pacific seawater shows that the identification of ree distributions affected by advection is only made possible by the high precision analysis we developed for this study the ce concentration we observe is relatively constant over 200 4500 m depth at both sites where we have complete profiles this unique constancy of ce is in contrast to the contiguous rees la and nd which show substantial concentration variations with depth

geochemistry of modern brachiopods applications and implications for oceanography and paleoceanography abstract modern rhynchonellida terebratulida thecideida and a few inarticulated brachiopods were collected live or soon after death at 30 locations from depths of 2 3940 m from the equator to high latitudes covering the atlantic pacific indian caribbean and mediterranean oceans seas well preserved fibers of the secondary layer combined with sr 450 1928 mg kg mn 1 199 mg kg and fe 1 610 mg kg contents confirm with few exceptions the excellent preservation of the modern brachiopod material evaluation of the stable isotope compositions was conducted on 276 specimens and on 374 published samples for a total database of 650 samples from 80 locations it revealed that oxygen isotope incorporation into shell calcite secondary layer of modern articulated brachiopods in most cases occurs in equilibrium with the ambient water and as such reflects surrounding environmental conditions thecideida as a group shallow water and low latitude incorporate oxygen isotopes 3 04 to 0 35 into shell calcite in equilibrium with their ambient water a large majority of genera and species of the terebratulida shallow water and low mid latitude also incorporate oxygen 2 30 to 3 48 into shell calcite in isotopic equilibrium with their surrounding water in contrast equilibrium incorporation of oxygen isotopes into shell calcite by the rhynchonellida is uncertain but a vital effect probably applies to the craniida the question of equilibrium disequilibrium incorporation of carbon isotopes into shell calcite of modern brachiopods remains unresolved at this time isotope compositions range up to 4 5 5 6 and 1 5 for 13 c and up to 5 5 5 9 and 0 3 for 18 o for shallow water low mid and high latitude brachiopods respectively strontium isotopes of modern brachiopods as expected show no significant variation with location latitude water depth temperature salinity and general water conditions once local habitat and ecological influences of fossil brachiopods from similar latitudes are considered their isotopic elemental values should be valuable diagenetic indicators and important oceanographic chemostratigraphic proxies

modelling karst geomorphology on different time scales abstract the evolution and flow in a karst aquifer is studied with numerical simulations based on the karst model karst aquifer simulation tool the aquifer consists of a three dimensional interconnected network of conduits representing fractures in the rock and a porous rock matrix representing the finer fissured system in the rock flow through the aquifer can be driven by both diffuse recharge from precipitation and localised sinking streams and the aquifer drains towards a large karst resurgence representing the base level superimposed onto the karst aquifer is a landscape which can evolve with time by small scale diffusive processes large scale river erosion and karst denudation fractures in the aquifer are enlarged with time by chemical dissolution enhancing the secondary porosity of the karst aquifer the enlargement of fractures results in a dramatic increase of the aquifer conductivity over several orders of magnitude and a change of flow patterns from an initially pore controlled to a heterogeneous fracture controlled aquifer during the evolution the water table is falling from an initially high position close to the land surface to a lower level coinciding with the actual base level two model scenarios are studied to elucidate the karst aquifer evolution in three dimensions the evolution models are then complemented by event type spring discharge modelling which can be used as a predictive tool for karst spring discharge and contaminant transport

modern carbonate ooids preserve ambient aqueous ree signatures abstract skeletal and non skeletal components of marine sedimentary rocks have been analyzed for the purpose of reconstructing the rare earth element ree and yttrium y compositions of paleo seawater but skeletal carbonates frequently have proven to be unreliable recorders of seawater chemistry here we present a systematic multi technique assessment of rare earth and other trace elements in ooid sands from the modern great bahama bank gbb marine and great salt lake gsl continental based on strong acid hydrofluoric and nitric and weak acid acetic digestions as well as laser ablation la of ooid cortices and nuclei the results show that bahamian ooid cortices possess shale normalized ree y features nearly identical to those of shallow seawater including limited contamination from siliciclastic rees an admixture of even 0 2 of detritally sourced material can modify the primary marine ree y patterns by for example increasing the light ree lree content mean values of la data for bahamian ooid cortices exhibit similar ree y signatures to those produced by acetic acid digestion but la data are generally noisier primarily as a result of low ree concentrations and the small volume of carbonate ablated in analysis screening out samples with ree 0 9 ppm returns a flat pattern suggesting similar degrees of lree depletion controlled by carbonate complexation under similar aqueous alkalinity conditions in great salt lake and bahamian waters in summary ooids can be a reliable proxy for ree y characteristics of ambient surficial waters when adopting suitable analytical methods including laser ablation that allow the identification and isolation of a contamination signal from siliciclastic detritus

geochemistry of late ordovician dalmanelloid brachiopods from laurentia testing the effects of paleolatitudinal gradient dalmanelloid brachiopod shells were collected from the upper ordovician lexington formation lower katian of kentucky sheguindah shale middle katian on manitoulin island ontario and the stony

rare earth element geochemistry of late devonian reefal carbonates canning basin western australia confirmation of a seawater ree proxy in ancient limestones rare earth element and yttrium ree y concentrations were determined in 49 late devonian reefal carbonates from the lennard shelf canning basin western australia shale normalized sn ree y patterns of the late devonian samples display features consistent with the geochemistry of well oxygenated shallow seawater a variety of different ancient limestone components including microbialites some skeletal carbonates stromatoporoids and cements record seawater like ree y signatures contamination associated with phosphate fe oxides and shale was tested quantitatively and can be discounted as the source of the ree y patterns co occurring carbonate components that presumably precipitated from the same seawater have different relative ree concentrations but consistent ree y patterns clean devonian early marine cements n 3 display ree y signatures most like that of modern open ocean seawater and the highest y ho ratios e g 59 and greatest light ree lree depletion average nd sn yb sn 0 413 sd 0 076 however synsedimentary cements have the lowest ree concentrations e g 405 ppb non contaminated devonian microbialite samples containing a mixture of the calcimicrobe renalcis and micritic thrombolite aggregates in early marine cement n 11 have the highest relative ree concentrations of tested carbonates average total ree 11 3 ppm stromatoporoid skeletons unlike modern corals algae and molluscs also contain well developed seawater like ree patterns samples from an estuarine fringing reef have very different ree y patterns with lree enrichment nd sn yb sn 1 possibly reflecting inclusion of estuarine colloidal material that contained preferentially scavenged lree from a nearby riverine input source hence devonian limestones provide a proxy for marine ree geochemistry and allow the differentiation of co occurring water masses on the ancient lennard shelf although appropriate partition coefficients for quantification of devonian seawater ree concentrations from out data are unknown hypothetical devonian canning basin seawater ree patterns were obtained with coefficients derived from modern natural proxies and experimental values resulting devonian seawater patterns are slightly enriched in lree compared to most modem seawaters and suggest higher overall ree concentrations but are very similar to seawaters from regions with high terrigenous inputs our results suggest that most limestones should record important aspects of the ree geochemistry of the waters in which they precipitated provided they are relatively free of terrigenous contamination and major diagenetic alteration from fluids with high non seawater like ree contents hence we expect that many other ancient limestones will serve as seawater ree proxies and thereby provide information on paleoceanography paleogeography and geochemical evolution of the oceans copyright c 2004 elsevier ltd

geophysical constraints on the crustal structure of the east european platform margin and its foreland based on the polcrust 01 deep reflection seismic profile abstract a new 240 km long deep seismic reflection profile polcrust 01 was recently acquired in se poland crossing the east european platform eep margin south east of the north german polish caledonides ngpc here we document geophysical field work and subsequent data processing and modeling results obtained from reflection seismic data are augmented by results of the first arrival tomography applied to co located extended offset refraction data as well as potential field modeling and comparison with the available wide angle reflection refraction data our preferred model of the crustal structure derived by integrating seismic potential field and geological data is composed of crustal blocks terranes separated by nearly vertical faults these are i intact part of the eep ii ysogory terrane iii malopolska terrane and iv carpathian mts with their basement reflective lower crust of the eep can be an inherited feature of crustal extension rifting or compressional tectonics acting at the cratonic margin the teisseyre tornquist zone ttz is depicted as a caledonian transcurrent accretion zone corresponding with the near vertical tomaszow fault bounding the ysogory terrane to the east the crust of the ysogory terrane suggests eep affinity although its middle lower crust thickness is highly reduced the malopolska terrane seems to be internally subdivided into blocks of different magnetic properties of the lower crust the carpathian frontal thrust is associated with a change in the rock properties in the deep basement an unknown crustal block which is not visible in seismic data alone the interpreted structure of the caledonian terranes and their tectonic boundaries favors a transcurrent style of a crustal accretion along the central and se polish segments of the ttz implying a very complex nature of the caledonian accretionary belt of central europe from an array of terranes displaced along the ttz to an accretionary wedge of the collisional ngpc orogen between nw poland and southern north sea area

location and migration of miocene quaternary volcanic arcs in the sw pacific region abstract we report new ar ar and u pb ages from ten rocks in the sw pacific region our results 1 establish a northward late miocene australian plate movement rate of 57 mm a for the lord howe hotspot chain 2 reinforce the previously established widespread nature of early miocene subduction related volcanism in onland and nearshore northern new zealand 3 indicate that leucotonalite xenoliths from raoul island are the products of quaternary kermadec arc magmatism rather than being cretaceous pliocene basement a synthesis of available sw pacific data emphasises that while there is a reasonably complete record of subduction related volcanism from at least 23 ma to the present day the process of back arc basin formation is highly episodic and asymmetric subduction related arcs stabilised along the taupo kermadec tonga arc from 2 ma to the present along the taranaki colville lau trend from 17 6 ma and along the three kings ridge northland plateau northland trend from 23 18 ma south of latitude 25 s back arc basin opening occurred during the early miocene and quaternary arc volcanic episodes but does not appear to have accompanied the 17 5 ma volcanism

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

the sedimentary flux of dissolved rare earth elements to the ocean abstract we determined pore fluid rare earth element ree concentrations in near surface sediments retrieved from the continental margin off oregon and california usa these sites represent shelf to slope settings which lie above within and below the oxygen minimum zone of the northeast pacific the sediments are characterized by varying degrees of net iron reduction with pore fluids from the shelf sites being generally ferruginous and the slope sediments having less pronounced iron reduction zones that originate deeper in the sediment package ree concentrations show maxima in shallow upper 2 10 cm subsurface pore fluids across all sites with concentrations that rise more than two orders of magnitude higher than seawater these pore fluid enrichments highlight the importance of a sedimentary source of rees to the ocean s water column here we use our measurements to estimate the diffusive flux of nd out of ocean sediments resulting in a global flux between 18 and 110 10 6 mol nd yr 1 while we do assume that our pore fluid profiles as well as the very limited data previously published are representative of a wide array of ocean environments this calculated flux can account for the modeled missing nd source flux 76 10 6 mol nd yr 1 in global budgets arsouze et al 2009 pore fluid normalized ree patterns show distinct variation in the middle ree and heavy ree enrichments with sediment depth and amongst sites these patterns show that the heavy ree enrichment of pore fluids at our deep slope site 3000 m water depth is closest to the heavy ree enrichment of seawater this observation supports the view that ree cycling within the upper ten centimeters of deep sea marine sediments as opposed to shallower continental shelf and slope sediments plays a significant role in controlling the integrated global ree flux from the pore fluids and consequently the broad scale ree pattern in seawater

seawater rare earth element patterns preserved in apatite of pennsylvanian conodonts past workers have used rare earth element patterns recorded in biogenic apatite as proxies for original seawater chemistry to explore the potency of this approach we analyzed pennsylvanian conodonts from limestones gray shales and black shales of the fort scott and pawnee formations desmoinesian and swope and dennis formations missourian in kansas missouri and iowa u s a analysis of individual platform conodonts from seven taxa using laser ablation inductively coupled plasma mass spectrometry la icp ms revealed a consistent enrichment in the middle rare earth elements mree analogous mree enrichment has been observed in authigenic apatite and bulk samples of phosphate rich black shales from the same formations importantly however phosphate depleted shales intimately associated with the p rich intervals are relatively depleted in mree these antithetic patterns argue convincingly for secondary migration from the bulk sediment into the phosphate and the extent of mree enrichment in the conodonts is correlated positively with the total ree content mree enrichment in conodonts does not vary systematically as a function of lithology stratigraphic level conodont genus geographic location or with independent estimates of paleoredox conditions in the bottom waters collectively these results argue for postmortem diagenetic ree uptake resulting in a pronounced and progressive mree enrichment any cerium anomalies if initially present were masked by diagenetic uptake of ree paleoenvironmental interpretations of conodont ree particularly for samples exhibiting mree enrichment should therefore be viewed with caution

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

deep resistivity structure of the trans european suture zone in central poland summary the deep resistivity structure was estimated along a 400 km profile in central poland crossing the malopolska massif mm the lysogory unit lu the trans european suture zone tesz and ending at the east european craton eec magnetotelluric transfer functions corresponding to 20 sites were supplemented by magnetovariational responses obtained at the geomagnetic observatories situated at the same tectonic units such a combination made it possible to extend the initial period range which is from fractions of a second to several hours up to months in order to reliably cover crustal and upper mantle depths the geoelectrical structures revealed using 2 d inversions do not contradict the known features of the lithosphere structure determined using seismic and gravity data along the profile the subsurface conductance varying from approximately 10 siemens at the inner part of the eec to about 600 siemens in the tesz is produced by sediments the deep part of which contains conductive highly mineralized water the existence of two crustal conductive faults at the southwest and northeast of the tesz were established mainly by the use of induction arrows it was also revealed that rather high mantle conductivity beneath the mm lu and tesz at depths of about 150 200 km contrasts with the resistive upper mantle of the eec this can be interpreted as the decrease of asthenosphere conductance and or as its submersion beneath the eec generally the results confirm the idea that the tesz forms not only specific seismic boundaries but also causes peculiar conductivity anomalies in the crust and upper mantle

brachiopod fabric classes and biogeochemistry implications for the reconstruction and interpretation of seawater carbon isotope curves and records abstract shell calcite of modern and ancient brachiopods is an important proxy in reconstructing oceanographic conditions of seawater our investigation reveals significant magnesium and carbon isotope relationships between two classes of ancient brachiopods brachiopods of the extinct class strophomenata constructed two or three layer shells with a primary layer of randomized granular calcite a secondary layer of cross bladed laminar calcite and at times a tertiary layer of large prismatic calcite contemporaneous but extant rhynchonellata also have two or three layer shells but their secondary layer consists of calcite fibers instead of cross bladed laminar calcite furthermore inter crystalline space is limited in between the fibers of the secondary layer of the rhynchonellata but higher in the laminar secondary layer of strophomenata 18 o values of the two classes of brachiopods from the same stratigraphic interval of the lopingian nesen formation of north iran show a considerable overlap with no significant difference p 0 263 in contrast carbon isotope values are significantly different p 0 001 between contemporaneous strophomenata mean 2 18 and rhynchonellata mean 4 13 an evaluation of literature data of permian asselian and carboniferous visean and serpukhovian strophomenata mean 2 32 n 59 and rhynchonellata mean 4 94 n 105 confirms a similar differentiation in their carbon isotope values its higher magnesium contents suggest that the strophomenata probably secreted shell calcite at a faster rate than their coeval rhynchonellata this process may account for the 13 c differentiation observed between specimens of these two brachiopod classes however the different amount and composition of the organic matter of the strophomenata may also play a role in shaping their more negative carbon isotope signature thus the class of brachiopod and their associated different fabric must be adjusted for in their 13 c results and taken into consideration during the reconstruction of paleozoic global 13 c carbonate based seawater curves invariably in some earlier studies undetected impacts imposed by the class fabric on 13 c may account for some of the variation or trends documented in deep time seawater 13 c curves reconstructed with brachiopod populations from north america europe and russia

rare earth elements in foraminifera tests abstract the concentrations of nine rare earth elements ree la ce nd sm eu gd dy er and yb have been determined in mixed species assemblages of foraminifera tests taken from atlantic ocean sediment core tops reductive cleaning techniques have revealed that ree are present in three phases in foraminifera tests collected from sea floor sediments ree included in the foraminiferal calcite matrix termed lattice ree ree associated with an authigenic femn rich phase adsorbed onto the surface of the test following the death of the organism termed coating ree and ree associated with alumino silicate detritus termed detrital ree which commonly infills the test chambers after burial in the sediment the concentrations of ree in the nondetrital lattice plus coating and lattice phases have been measured in this study approximately 90 of the ree measured in the non detrital phase reside in the coating phase the remainder being present in the lattice phase these data have been used to investigate the relationship between the distribution of dissolved ree in the ocean and in the coating and lattice phases in addition to the ree the concentrations of mn fe cu al and po4 have been measured as an aid to characterisation of the various phases

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

dissolved rare earth elements in the southern ocean cerium oxidation and the influence of hydrography abstract analysis of dissolved ree distributions in the southeastern atlantic ocean has revealed that progressive oxidative removal of dissolved ce from deepwater 1 km occurs over the mixing time of the oceans ce anomaly ce ce values measured in deep waters from the southeastern atlantic are similar to but slightly higher than those from deep ocean stations throughout the indian and pacific oceans typically falling in the range 0 08ce ce 0 12 only deepwater samples from the north atlantic exhibit values greater than ce ce 0 12 with the exception of southeastern atlantic bottomwaters which are influenced by antarctic bottomwater covariation of dissolved ree concentrations with salinity and or dissolved si concentrations at this site has allowed dissolved ree compositions for various southern ocean water masses to be predicted end member concentrations for antarctic bottom water aabw derived in this way indicate high dissolved ree concentrations similar to average pacific deep water but with significantly enhanced dissolved ce concentrations and less pronounced hree enrichment this result is consistent with the proximity of our study site to active aabw deepwater formation and evolution of that water mass during transport to the pacific ocean

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

rare earth elements of shallow water articulated brachiopods a bathymetric sensor abstract variations in environmental physicochemical parameters result in corresponding changes in seawater rare earth element ree distributions for an archive to be utilized in paleoceanographic and paleoenvironmental reconstructions it should record these variations therefore an archive s proxy potentiality should be assessed analogous to modern oceanic settings articulated brachiopods of several shallow water localities the mean ree sn pattern of shallow water brachiopods is significantly different from that of their deep water counterparts with lower enrichments in lrees and mrees and depletion in hrees depth exercises a major control on the lree and mree fractionation with a milder one on hree fractionation the ce ce anomaly is not affected by either of these parameters in shallow water settings but in deep settings the depth effect dominates due to the importance of depth on ree fractionation in the shells from shallow settings their lree sn to hree sn ratios l h were divided into six discrete intervals for the bathymetric sensor the bathymetric sensor was applied to some fossils and whole rock in order to estimate their paleodepths the evaluation was successful in placing the permian gyanyima the pennsylvanian naco boggy and the silurian chicotte becscie and jupiter formations in shallow depths

rare earth element association with foraminifera abstract neodymium isotopes are becoming widely used as a palaeoceanographic tool for reconstructing the source and flow direction of water masses a new method using planktonic foraminifera which have not been chemically cleaned has proven to be a promising means of avoiding contamination of the deep ocean palaeoceanographic signal by detrital material however the exact mechanism by which the nd isotope signal from bottom waters becomes associated with planktonic foraminifera the spatial distribution of rare earth element ree concentrations within the shell and the possible mobility of ree ions during changing redox conditions have not been fully investigated here we present ree concentration and nd isotope data from mixed species of planktonic foraminifera taken from plankton tows sediment traps and a sediment core from the nw atlantic we used multiple geochemical techniques to evaluate how where and when rees become associated with planktonic foraminifera as they settle through the water column reside at the surface and are buried in the sediment analyses of foraminifera shells from plankton tows and sediment traps between 200 and 2938 m water depth indicate that only 20 of their associated nd is biogenically incorporated into the calcite structure the remaining 80 is associated with authigenic metal oxides and organic matter which form in the water column and remain extraneous to the carbonate structure remineralisation of these organic and authigenic phases releases ions back into solution and creates new binding sites allowing the nd isotope ratio to undergo partial equilibration with the ambient seawater as the foraminifera fall through the water column analyses of fossil foraminifera shells from sediment cores show that their ree concentrations increase by up to 10 fold at the sediment water interface and acquire an isotopic signature of bottom water adsorption and complexation of ree3 ions between the inner layers of calcite contributes significantly to elevated ree concentrations in foraminifera the most likely source of ree ions at this stage of enrichment is from bottom waters and from the remineralisation of oxide phases which are in chemical equilibrium with the bottom waters as planktonic foraminifera are buried below the sediment water interface redox sensitive ion concentrations are adjusted within the shells depending on the pore water oxygen concentration the concentration of ions which are passively redox sensitive such as ree3 ions is also controlled to some extent by this process we infer that a the nd isotope signature of bottom water is preserved in planktonic foraminifera and b that it relies on the limited mobility of particle reactive ree3 ions aided in some environments by micron scale precipitation of mnco3 this study indicates that there may be sedimentary environments under which the bottom water nd isotope signature is not preserved by planktonic foraminifera tests to validate other core sites must be carried out before downcore records can be used to interpret palaeoceanographic changes

acquisition of the neodymium isotopic composition of the north atlantic deep water the north atlantic deep water nadw neodymium isotopic composition nd ic is increasingly used in oceanography and paleoceanography to trace large scale circulation and weathering processes notably to investigate past variations of the global thermohaline circulation although the present day nadw nd ic is well characterized at nd 13 5 the acquisition of this isotopic signature in other words the causes of this value has so far been very sparsely documented such an understanding is however fundamental to the interpretation of paleo records nd ic and rare earth element concentrations were measured at 9 stations within the north atlantic subpolar gyre signature cruise summer 1999 the comparison of this data set with our understanding of water mass circulation provides a description of how the three layers constituting the nadw the labrador sea water lsw nd 13 9 0 4 north east atlantic deep water neadw nd 13 2 0 4 and north west atlantic bottom water nwabw nd 14 5 0 4 acquire their nd ic through distinct water mass mixings and lithogenic inputs these different mechanisms acting upon water masses from very diverse sources seem to bring the nd ic of the three nadw layers to values close together and similar to that of the nadw it is suggested that sediment seawater interactions significantly lower the neadw and nwabw nd ic along the south east greenland margin since these interactions do not significantly modify the nd content of these water masses sediment remobilizations leading to the nd ic variations are probably associated with nd removal fluxes from the water mass toward the sediment a process called boundary exchange on the other hand lsw seems to acquire its nd ic from the subpolar mode waters from which it is formed by deep convection and no other mechanism needs to be invoked its unradiogenic signature could ultimately be linked to fresh water runoff from the canadian shield these conclusions should allow more precise interpretations of paleoceanographic nd ic records taking into account the distinct histories of the three nadw layers including distinct water mass mixings and distinct lithogenic inputs

lithospheric structure of the trans european suture zone along the ttz cel03 seismic transect from nw to se poland abstract the large scale celebration 2000 seismic experiment investigated the velocity structure of the crust and upper mantle between western portion of the east european craton eec and the eastern alps this area comprises the trans european suture zone the carpathian mountains the pannonian basin and the bohemian massif this experiment included 147 chemical shots recorded by 1230 seismic stations during two deployments good quality data along 16 main and a few additional profiles were recorded one of them profile cel03 was located in southeastern poland and was laid out as a prolongation of the ttz profile performed in 1993 this paper focuses on the joint interpretation of seismic data along the nw se trending ttz cel03 transect located in the central portion of the trans european suture zone first arrivals and later phases of waves reflected refracted in the crust and upper mantle were interpreted using two dimensional tomographic inversion and ray tracing techniques this modelling established a 2 d quasi 3 d p wave velocity lithospheric model four crustal units were identified along the transect from northwest to southeast thickness of the crust varies from 35 km in the pomeranian unit nw to 40 km in the kuiavian unit to 50 km in the radom ysogory unit and again to 43 km in the narol unit se the first two units are thought to be proximal terranes detached from the eec farther to the southeast and re accreted to the edge of the eec during the early palaeozoic the origin of the remaining two units is a matter of dispute they are either portions of the eec or other proximal terranes in the area of the polish basin first two units the p wave velocity is very low vp

the effect of diagenesis and fluid migration on rare earth element distribution in pore fluids of the northern cascadia accretionary margin analytical challenges in obtaining high quality measurements of rare earth elements rees from small pore fluid volumes have limited the application of rees as deep fluid geochemical tracers using a recently developed analytical technique we analyzed rees from pore fluids collected from sites u1325 and u1329 drilled on the northern cascadia margin during the integrated ocean drilling program iodp expedition 311 to investigate the ree behavior during diagenesis and their utility as tracers of deep fluid migration these sites were selected because they represent contrasting settings on an accretionary margin a ponded basin at the toe of the margin and the landward tofino basin near the shelf s edge ree concentrations of pore fluid in the methanogenic zone at sites u1325 and u1329 correlate positively with concentrations of dissolved organic carbon doc and alkalinity fractionations across the ree series are driven by preferential complexation of the heavy rees simultaneous enrichment of diagenetic indicators doc and alkalinity and of rees in particular the heavy elements ho to lu suggests that the heavy rees are released during particulate organic carbon poc degradation and are subsequently chelated by doc ree concentrations are greater at site u1325 a site where shorter residence times of poc in sulfate bearing redox zones may enhance ree burial efficiency within sulfidic and methanogenic sediment zones where ree release ensues cross plots of la concentrations versus cl li and sr delineate a distinct field for the deep fluids z 75 mbsf at site u1329 and indicate the presence of a fluid not observed at the other sites drilled on the cascadia margin changes in ree patterns the presence of a positive eu anomaly and other available geochemical data for this site suggest a complex hydrology and possible interaction with the igneous crescent terrane located east of the drilled transect

rare earth element geochemistry of hydrothermal deposits from the active tag mound 26 n mid atlantic ridge the rare earth element ree geochemistry of various phases from the active tag hydrothermal mound has been examined and related to their mineralogy and fluid chemistry the mound deposits range from black and white smoker chimneys massive anhydrite sulphide mixtures oxides and ochres all phases except black smoker chimney anhydrite demonstrate a positive eu anomaly when normalised to chondrite ree values ree substitution into sulphide and sulphate phases appears to be strongly influenced by crystallographic control for all ree other than eu precipitation of anhydrite within the tag mound is the major mechanism for removal of ree during mound circulation and 0 15 0 35 g anhydrite is inferred to precipitate from every kg of fluid venting from the white smoker chimneys oxides from the mound fall into three different categories with distinct ree patterns oxide rims on sulphides atacamite bearing oxides and silica rich fe oxides and ochres the oxide rim phases contain sulphide and seawater derived rees whereas the atacamite bearing oxides and the ochreous material exhibit no seawater signature which suggests precipitation from or alteration by a modified hydrothermal fluid

changes in dissolved oxygen in the southern ocean with climate change 1 climate models predict that increasing greenhouse gases in the atmosphere will change our climate however the range of observations available to assess these model predictions is limited we have utilized an ocean biogeochemical model to project the impact of climate change on the oxygen cycle in the ocean and the air sea exchange of oxygen with climate change our model predicts an outgassing of oxygen from the ocean in the model the southern ocean is the region that displays the largest change in the air sea exchange of oxygen with climate change the reduced oxygen uptake in the southern ocean is dominated by a reduction in convective mixing and in the subduction rate of bottom water which decreases the amount of dissolved oxygen in the southern ocean our model results suggest that dissolved oxygen is sensitive to changes in southern ocean circulation revealing the potential to use dissolved oxygen to test model predictions of climate change from southern ocean observations collected 28 years a part we observed a decrease in dissolved oxygen that was consistent with model climate change simulation this provides credibility to the climate model predictions additional analysis and observations of dissolved oxygen are needed to substantiate our climate model simulations

neotethys seawater chemistry and temperature at the dawn of the end permian mass extinction abstract the end of the permian was a time of great death and massive upheaval in the biosphere atmosphere and hydrosphere over the last decades many causes have been suggested to be responsible for that catastrophe such as global warming anoxia and acidification the gyanyima limestone block was an open ocean seamount in the southern neotethys at subtropical latitude and it affords us insight into open ocean oceanographic changes during the end of the permian after careful screening using multiple tests we reconstructed carbonate seawater curves from the geochemical data stored in pristine brachiopod shell archives from the shallow water limestone of the changhsingian gyanyima formation of tibet the reconstructed strontium isotope curve and data for the late changhsingian are relatively invariant about 0 707013 but in the upper part of the succession the values become more radiogenic climaxing at about 0 707244 the 87 sr 86 sr curve and trend are similar to those observed for the upper permian succession in northern italy but dissimilar less radiogenic to whole rock results from austria iran china and spitsbergen the ce ce anomaly results ranging from 0 310 to 0 577 for the brachiopods and from 0 237 to 0 655 for the coeval whole rock before the event and of 0 276 for whole rock during the extinction event suggest normal redox conditions these ce values are typical of normal open ocean oxic water quality conditions observed in modern and other ancient counterparts the biota and ce information clearly discounts global anoxia as a primary cause for the end permian biotic crisis carbon isotopes from brachiopod shells and whole rock are relatively invariant for most of the latest permian interval which is in stark contrast to the distinct negative carbon isotope excursion observed near and about the event estimates of seawater temperature at shallow depth fluctuated from 22 2 to 29 0 c up to unit 8 2 and then gradually rise from 29 7 c in unit 8 13 to values exceeding 35 c at a stratigraphic level about 120 ky before the permian triassic boundary and just before the onset of the extinction interval this dramatic increase in seawater temperature has been observed in global successions from tropical to mid latitude and from restricted to open ocean localities e g northern italy iran the brachiopod archive and its geochemical proxies from tibet support the paradigm that global warming must have been an important factor of the biotic crisis for the terrestrial and marine faunas and floras of the late paleozoic world

karstification beneath the birs weir in basel switzerland a 3d modeling approach we present a three dimensional model describing the evolution of a gypsum karst aquifer along the birs river near basel in switzerland here a small dam site was built in 1890 to generate hydro electric power after subsidence of a nearby highway geophysical and geological field studies have been carried out and a detailed hydrogeological model has been developed these observations identified a karstified weathered zone as the reason for the subsidence to prevent any further damage remedial construction measures have been carried out we employ our numerical model karstaquifer which simulates the temporal evolution of a karst system by dissolution increasing the porosity in the aquifer we used results from geological and geophysical investigations as a priori information for implementing the initial boundary conditions into our three dimensional numerical model our model accounts for topography precipitation and geology and especially for the anisotropy of the local bedrock it can successfully reproduce the weathered zone in its current horizontal and vertical extent we cm also simulate the possible evolution of the aquifer following a remedial construction phase therefore taken together with the geophysical and geological observations and the groundwater model our three dimensional karst aquifer evolution model enhances the understanding of the development of this heterogeneous karst aquifer system c 2012 elsevier b v all rights reserved hydrogeologie der nordwestschweiz grundwasser

karstification of aquifers interspersed with non soluble rocks from basic principles towards case studies abstract we have developed a numerical model able to describe the karstification of aquifers in fractured rocks containing soluble limestone or gypsum and insoluble layers when water is flowing along fractures crossing the soluble layers it is able to dissolve the material there to increase the aperture width of the conduit and consequently to increase the local hydraulic conductivity depending on the thickness and the distribution of these layers the dissolution can be active only for limited periods or during the whole evolution time fractures located in insoluble layers do not change at all we are interested in the integral effect of these local processes and study four simplified scenarios of karstification along a prominent wide conduit crossing a fractured limestone block we keep the initial and the boundary conditions the same for all scenarios and vary only in the amount and the distribution of the soluble material we demonstrate that aquifers in 100 limestone without any insoluble layers develop along areas with high hydraulic conductivities and high hydraulic gradients creating channel like pathways on the other hand aquifers containing soluble layers with limited thickness develop faster and exhibit diffuse patterns determined by the chemical properties of the rock the second part of the paper is a step towards modeling of real karst systems we present the evolution of an aquifer located in the vicinity of a large hydraulic structure all initial and boundary conditions except the amount and the distribution of the soluble rock remain the same for all scenarios as a material example for the bedrock we chose gipskeuper from an aquifer along the birs river in switzerland this rock consists of soluble gypsum layers and insoluble clays and marls with typical layer thickness in the range of millimeters to centimeters the basic processes discussed in the first part of the paper remain valid we demonstrate that large insoluble zones can impair the karstification process and even completely block it while areas with thin soluble layers can provide a preferential pathway and decrease the evolution times considerably finally we show that the evolution of the leakage rates and the head distribution within the aquifer can sometimes reveal misleading information about the stage of karstification and the safeness of the dam our model can be used not only to study simplified geological settings and basic processes but also to address some of the complications arising when modeling real aquifers

the incorporation of rare earth elements in modern coral we report measurements of rare earth elements rees which show that these trace elements are being incorporated in modern coral in proportion to their seawater concentrations four bermuda north rock coral species diploria strigosa diploria labyrinthiformis montastrea annularis and porites astreoides and two tarawa atoll samples of the species hydnophora microconos were analyzed by ti idms following cleaning techniques to isolate the lattice bound rees based on the replicate analyses of the same piece of diploria strigosa excellent reproducibility was achieved the ree ca ratios 0 1 3 nmol mol of the bermuda and tarawa corals are similar to those of cd ca the trace metal with the lowest seawater concentration used in coral studies with the exception of ce the distribution coefficients e g dnd nd coral nd seawater ca seawater ca coral between bermuda coral lattice and sargasso seawater have fairly flat patterns across the ree series the values of d range from 1 to 3 like those reported for other trace elements in corals this suggests but does not prove that rees are incorporated in the aragonite lattice of these corals the shale normalized ree patterns of the tarawa corals also have seawater like distributions however no local seawater data are available to calculate values of d two bermuda species d labyrinthiformis and p astreoides have values of d for ce that are high with respect to the d values of la and nd implying that there is preferential uptake of ce into the lattice this may be related to the fact that ce is the only ree with an active redox chemistry in seawater there is considerable interest in using the chemical and isotopic composition of coral as indicators of climatic variations the combination of ree ca ratios and neodymium isotopic composition of coral has the potential to help understand important natural processes a primary application could be directed toward a tracer for river water discharge in tropical regions and by inference a proxy for rainfall climate variation and weathering history this application would exploit the fractionated composition of rees in river water as a terrigenous signature in coastal corals

rare earth elements in suspended particulate material of north atlantic surface waters on a transect between the northwest and northeast atlantic ocean 30 n 60 w to 60 n 2 w june july 1996 suspended particulate material spm in 24 near surface water samples 4 to 22 m3 with spm concentrations between 32 and 447 mg m 3 has been collected using a large volume centrifuge system the samples have been analyzed for y the rare earth elements rees and major inorganic and biogenic carrier phases such as al clay fe mn poc opal and caco3 the concentration pattern of particulate rees roughly follows the spm distribution average values pmol l 1 are for y 2 36 la 0 84 ce 0 82 pr 0 17 nd 0 67 sm 0 14 eu 0 030 gd 0 15 tb 0 024 dy 0 16 ho 0 036 er 0 12 tm 0 018 yb 0 13 and lu 0 022 extensive variability in negative ce anomalies have been observed along our transect with the strongest anomalies in areas of high poc abundances significant fractionation between lrees and hrees has been found for all major particulate phases these data are characterized by 1 strong relationships p 0 001 exist between concentrations of nonlithogenic excess hrees tb lu and poc values indicating that complexation with organic ligands promotes temporary hree enrichment on solid surfaces 2 the behavior of particulate fe and mn fractions is decoupled while fe and al clay phases exhibit preferential uptake of lrees la gd with crust like signatures particulate excess mn is strongly coupled to the poc phase r2 0 82 and to excess hrees we therefore suggest that the enrichment of rees in mn particles occurs via the formation of biogenic material probably mediated by bacteria and is not caused by adsorption onto mn oxihydroxides another result is that y in all studied relationships with the major inorganic and biogenic phases is very similar to ho implying their chemistries in surface ocean particulates are dominated by similar valency and ionic radii the y ho ratios average of 69 7 mol mol 1 have been very constant along our transect and lie in between the ratios for seawater 100 and continental crust 50

migration of sharks into freshwater systems during the miocene and implications for alpine paleoelevation trace element and isotopic compositions of fossilized shark teeth sampled from miocene marine sediments of the north alpine molasse basin the vienna basin and the pannonian basin generally show evidence of formation in a marine environment under conditions geochemically equivalent to the open ocean in contrast two of eight shark teeth from the swiss upper marine molasse locality of la moliere have extremely low 18o values 10 3 and 11 3 and low 87sr 86sr ratios 0 707840 and 0 707812 compared to other teeth from this locality 21 1 22 4 and 0 708421 0 708630 the rare earth element ree abundances and patterns from la moliere not only differ between dentine and enameloid of the same tooth but also between different teeth supporting variable conditions of diagenesis at this site however the ree patterns of enameloid from the exotic teeth analyzed for o and sr isotopic compositions are similar to those of teeth that have o and sr isotopic compositions typical of a marine setting at this site collectively this suggests that the two exotic teeth were formed while the sharks frequented a freshwater environment with very low 18o content and sr isotopic composition controlled by mesozoic calcareous rocks this is consistent with a paleogeography of high elevation 2300 m miocene alps adjacent to a marginal sea

sea ice winter convection and the temperature minimum layer in the southern ocean the structure of the near surface waters in the southern ocean poleward of the antarctic polar front but away from continental margins is investigated with a three dimensional time dependent numerical model which resolves the annual sea ice cycle the growth and decay of the ice field is predicted using one of semtner s 1976 thermodynamic ice models in terms of specified atmospheric data and computed thermohaline characteristics of the ocean layers the ice field is found to be sensitive to the lateral advection of heat by the oceanic circulation as well as vertical heat transports due to deep winter convection the model treats the temperature minimum layer in the southern ocean as the remnant of a deep winter mixed layer which becomes capped by surface heating and precipitation in summer the predicted thermohaline characteristics of the temperature minimum layer and the surface mixed layer are in good agreement with observations finally the annual air sea heat exchange predicted by the model is discussed the model s predicted area averaged heat loss experienced by the ocean south of the atlantic polar front is much smaller than was previously estimated this is attributed to errors in the southern region of the model domain it is suggestedmore that models which include the interactions between sea ice and surface deep and bottom waters along the continental margins are needed to investigate this region less

venezuela basin of the caribbean sea stratigraphy and sediment distribution abstract the venezuela basin of the caribbean sea averages approximately 4800 m deep and is underlain by oceanic type crust it is bounded on the east and west by pre cenozoic ridges and on the north and south by late cenozoic deformed belts the age of the crust underlying the venezuela basin has not been firmly established but based upon drilling it is at least as old as late cretaceous the age lithology and origin of rock which underlies seismic reflecting horizon b the deepest horizon encountered by drilling is uncertain rocks which coincide with horizon b are tholeiitic basalt sills intruding pelagic carbonate sedimentary rock of late cretaceous age sedimentary strata above horizon b in the central venezuela basin are well known from deep sea drilling and by seismic delineation of their thickness the dominant sediment is pelagic carbonate seismic horizon a marks the onset of lithification pelagic chalk and marl oozes overlie limestones and marl sediments in the a b interval average approximately 500 m in thickness but vary from 0 to over 1000 m in thickness the thickest sections coincide with the venezuelan abyssal plain and with the base of the beata ridge in the northwest corner of the basin in the south central portion of the basin most of the a b section is absent the post a sediments average approximately 400 m in thickness with variations between 100 and 2600 m the principal thickening in this section is in the southeastern corner of the basin bounded by the curacao and aves ridges abyssal plain turbidites appear to be limited to the post a section

lithospheric structure beneath trans carpathian transect from precambrian platform to pannonian basin celebration 2000 seismic profile cel05 1 in 2000 a consortium of european and north american institutions completed a huge active source seismic experiment focused on central europe the central european lithospheric experiment based on refraction or celebration 2000 this experiment primarily consisted of a network of seismic refraction profiles that extended from the east european craton along and across the trans european suture zone region in poland to the bohemian massif and through the carpathians and eastern alps to the pannonian basin the longest profile cel05 1420 km is the focus of this paper the resulting two dimensional tomographic and ray tracing models show strong variations in crustal and lower lithospheric structure clear crustal thickening from the pannonian basin 24 25 km thick to the trans european suture zone region 50 km together with the configuration of the lower lithospheric reflectors suggests northward subduction of mantle underlying carpathian pannonian plate under the european plate this however conflicts with strong geological evidence for southward subduction and we present three tectonic models that are to not totally mutually exclusive to explain the lithospheric structure of the area 1 northward old subduction of the pannonian lithosphere under the east european craton in the jurassic lower cretaceous 2 a collisional zone containing a crocodile structure where carpatho pannonian upper crust is obducting over the crystalline crust of the east european craton and the carpathian pannonian mantle lithosphere is underthrusting cratonic lower crust and 3 lithosphere thinning due to the effects of neogene extension and heating with the slab associated with young subduction southward in the miocene having been either detached and or rolled back to the east in the last case the northwestward dipping in the lithosphere can be interpreted as being due to isotherms that could represent the lithosphere asthenosphere boundary in the pannonian region

crustal seismic velocity structure of southern poland preserved memory of a pre devonian terrane accretion at the east european platform margin the updated geological and potential fields data on the east european platform margin in se poland confirm the existence of several regional units differing in ediacaran to silurian development the upper silesian block malopolska block and ysogory block all the blocks are characterized by a distinct crustal structure seen in vp velocity models obtained from the seismic refraction data of the celebration 2000 programme the first two units are interpreted as exotic terranes initially derived from avalonia type crust and ultimately accreted before the late early devonian the ysogory block is probably a proximal terrane displaced dextrally along the baltica margin the sutures between the terranes do not precisely match lateral gradients in vp models this is partly explained by a limited resolution of refraction seismic data 20 km wide interpretative window most of the difference is related however to a post accretionary tectonism mainly variscan transtension transpression the latter processes took advantage of lithospheric memory recorded earlier as zones of rheological weakness along the former suture zones the course of the east european platform margin teisseyre tornquist zone corresponds most likely to the nowe miasto zawichost fault marking the ne boundary of the proximal ysogory terrane

rare earth elements and yttrium in seawater icp ms determinations in the east caroline coral sea and south fiji basins of the western south pacific ocean abstract using inductively coupled plasma mass spectrometry icp ms vertical profiles of yttrium and all the rare earth elements rees in seawater were obtained at three locations in the western south pacific the east caroline coral sea and south fiji basins based on the data we have analyzed the inter ree iii relationships and found that ree iii s heavier than dy and particularly close neighbors show strong coherencies in their oceanic behavior considering that the heavy ree iii s are less particle reactive than the light and middle ree iii s and that they have very tight correlations with regressions passing almost through the origin the neighboring element ratios of the heavy ree iii s behave virtually conservatively and are suitable as tracers of water masses the dy ho er system is practically good because its dynamic range signal to noise ratio is large in the ocean the highest ho dy ratios 0 31 are found in intermediate and deep waters throughout the western south pacific which overlie the antarctic bottom water with a low ho dy ratio 0 27 these high ho dy waters are probably formed in the polar and subantarctic frontal zone and advect northward ree iii data provide better insights into the deep water recirculation in the south pacific than those discussed based upon the regular oceanographic properties alone

the border of the east european craton in south eastern poland based on gravity and magnetic data according to recent geological interpretations the border of the east european craton eec in se poland is located in the ne foreland of the holy cross mts results of gravity and magnetic anomaly interpretations presented herein confirm this according to 3d and 2d gravity and magnetic modelling the eec borders the sw flank of the regional crystalline feature with increased magnetic and density properties which occur in the se part of the teisseyre tornquist zone ttz this flank rests near a deep fracture delimiting the ttz on sw the feature is a cause of the regional magnetic gradient observed there two se nw belts of residual gravity anomalies dislocations are also identified in the magnetic gradient zone cutting mesozoic and palaeozoic formations results of geophysical and geological investigations show the importance of this dislocation zone and confirm that it occurs in all crustal complexes and the upper mantle

rare earth elements in pore waters of marine sediments abstract the rare earth elements rees were measured in pore waters of the upper 25 cm of sediment from one site off peru and three sites on the california margin the pore water ree concentrations are higher than sea water and show systematic down core variations in both concentration and normalized pattern from these analyses and from comparison to other chemical species measured dissolved fe mn ba oxygen nitrate phosphate it is suggested that pore water rees can be grouped into three categories those that are from an fe source those that are from a poc source and cerium oxide rees from the fe source appear where anoxia is reached they have a distinctive middle ree mree enriched pattern the concentrations in this source are so elevated that they dominate ree trends in the fe oxide reduction zone the net result of flux from the poc source is relative enrichment of heavy rees hrees over light rees lrees reflecting remineralizing poc and complexation with doc a common linear ree pattern seen in both oxic and anoxic sediments is associated with this poc source as well as a hree enriched pattern that is seen in surficial sediments at the peru site overall the pore water results indicate that mn oxides are not an important carrier of rees in the oceans a ree biogeochemical model is presented which attempts to reconcile ree behavior in the water and sediment columns of the oceans the model proposes that poc fe oxide and ce oxide sources can explain the ree concentration profiles and relative abundance patterns in environments ranging from oxic sea water to anoxic pore water the model is also consistent with our observation that the ce anomaly of pore water does not exceed unity under any redox condition

the deep crust beneath the trans european suture zone from a multiscale magnetic model we present a 3 d interpretation of the deep magnetic sources beneath the main geological structure of central eastern europe the trans european suture zone tesz we used a multiscale analysis of aeromagnetic data based on a multiscale data set generated by upward continuation of the european and mediterranean magnetic project data set from 5 to 100 km altitude we also computed the multiscale total gradient t of the multiscale field both of the multiscale data sets allow us to discriminate the main crustal contributions to the field at various scales and we showed that at large altitudes the field is dominated by the sole effect of the tesz the multiridge geometric method was very useful in studying the complex features of the main crustal interfaces either shallow or deep the interpreted interfaces are largely agreement with geological models based on seismic surveys and in some cases complete the models out of the analyzed region in order to estimate the deepest source depths in the tesz region we applied the multiridge method to the large scales 50 100 km altitude obtaining a set of singular points at depths ranging between 35 and 40 km considering the heat flow trend and the geological models around the tesz area we found a meaningful correspondence among the location of the estimated singular points and the most abrupt variations and complex morphology features of the moho boundary the multiridge estimates are consistent with known structural information and can be used for a 3 d representation of the moho depth along the tesz

δ18o and ree contents of phosphatic brachiopods a comparison between modern and lower paleozoic populations 18o values of both carbonate 18 7 25 1 and phosphate 15 1 16 7 components of the francolite from the fossil brachiopod shells are interpreted as the result of a partial resetting of pristine isotopic compositions the similarity of hat shape ree patterns of some lower ordovician linguloids with those of extant littoral specimens suggests the preservation of a 500 myr old record of ree marine chemistry in agreement with the known paleogeography the phosphatic brachiopods have been deposited in a coastal environment under shallow and oxygenated marine waters however the contents and distribution of ree in some strongly altered brachiopod shells reveal an alteration of the original negative ce anomalies and both nd and sm enrichments that transformed the initial hat shape patterns of linguloids into strongly convex or bell shape patterns

formation regions of subantarctic mode water detected by ofes and argo profiling floats 1 we investigated the distribution of the deep mixed layer in the southern ocean where subantarctic mode water samw forms by using argo profiling floats and the ocean general circulation model for the earth simulator ofes the mixed layer depth mld generally increased eastward from 50 180 e and from 180 80 w with distinct local maxima near major bathymetric features a sudden transition from deep to shallow mixed layer was found along the equatorward limit of the deep mixed layer this diagnosed mld front coincides with the line of ug s 0 indicating the distributions of the general deepening and local maxima of mld were affected by near surface geostrophic flow the flow is steered by the major bottom topographies and the local mld maxima occurred where the flow direction was deflected southward this implies a link between the bathymetric features and formation of thick samw

rare earth elements in deep water articulated brachiopods an evaluation of seawater mass abstract modern articulated brachiopods of the orders rhynchonellids and terebratulids were obtained from below the neritic zone of the caribbean sea north atlantic south pacific and southern oceans to evaluate the proxy potential of their rare earth element ree contents shells of the two orders display similar ree distribution coefficients that vary consistently within the series in response to changes in ionic radii relative to that of the ca 2 cation which in turn excludes the possibility of a biological control on their ree incorporation the calculated log k d values for the brachiopods are similar to those documented in other investigations and as a consequence shell calcite is enriched in ree concentrations relative to ambient water masses by an average of 0 81 10 5 brachiopods from the four areas yielded lree sn and mree sn characteristics of their ambient water mass exhibiting gradual enrichments with increasing atomic number as well as negative ce sn excursions their hree sn values on the other hand define a trend that varies with water depth overall the ce ce profile of open water deep sea brachiopods is coupled with that of the ambient seawater our study confirms the robustness of rees in deep water 500 m articulated brachiopods and supports their use as a proxy of paleo oceanography specifically water mass and redox

biogenic and abiogenic low mg calcite blmc and almc evaluation of seawater ree composition water masses and carbonate diagenesis the ree and shale normalized paas reesn values of modern brachiopods biogenic low mg calcite blmc represented by several species from high to low latitudes from shallow to deep waters and from warm and cold water environments define three distinct average seawater trends the warm and cold water brachiopods define two indistinguishable p 0 050 groups that mimic open ocean seawater ree chemistry exhibiting the typical lree enrichment with a slightly positive to negative ce anomaly followed by an otherwise invariant series other recent brachiopods from an essentially siliciclastic seabed environment are distinct in both ree and reesn trends from the previous two populations showing a slight enrichment in the mrees and an increasing trend in the hrees other groups of modern brachiopods are characterized by elevated reesn trends relative to the normal groups as well as by complexity of the series trends the most characteristic feature is the decrease in the hrees in these brachiopods from areas of unusual productivity i e such as upwelling currents fluvial input and aerosol dust deposition preserved brachiopods from the eocene and silurian exhibit reesn trends and ce anomalies similar to that of the open ocean modern brachiopods although their enriched ree concentrations suggest precipitation of blmc influenced by extrinsic environmental conditions preservation of the blmc was tested by comparing the ree and reesn trends of preserved eocene brachiopods to those of oligocene brachiopods that were altered in an open diagenetic system in the presence of phreatic meteoric water the altered blmc is enriched by approximately one order of magnitude in both ree and reesn trends relative to that in blmc of their preserved counterparts similarly the ree and reesn of preserved silurian brachiopod blmc were compared to those of their enclosing altered lime mudstone which exhibits features of partly closed system phreatic meteoric water diagenesis despite these differences in the diagenetic alteration systems and processes the rees and reesn trends of the blmc of altered brachiopods and of originally mixed mineralogy lime mudstones now diagenetic low mg calcite are enriched by about one order of magnitude relative to those observed in the coeval and preserved blmc in contrast to the changes in ree and reesn of carbonates exposed to phreatic meteoric water diagenesis are the ree compositions of late burial calcite cements precipitated in diagenetically open systems from burial fluids the ree and reesn trends of the burial cements mimic those of their host lime mudstone with all showing slight lree enrichment and slight hree depletion exhibiting a chevron pattern of the reesn trends the overall enrichment or depletion of the cement reesn trends relative to that of their respective host rock material reflects not only the openness of the diagenetic system but also strong differences in the elemental and ree compositions of the burial fluids evaluation of the ce ce sn and la pr pr sn anomalies suggests precipitation of the burial calcite cements essentially in equilibrium with their source fluids

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

the ree and end of 40 70 ma old fish debris from the west african platform ree concentrations and nd isotopic compositions have been determined in late cretaceous early cenozoic fish debris from west african and israeli platform sediments and show a strong regional control independent of time except for those from the northern morocco it is suggested that although diagenetic fluids do not contribute ree s directly to the phosphatic debris they may significantly change the ce anomaly and the end t value of the epicontinental seas which in turn control the ree in marine phosphates it is shown that over the investigated period the north moroccan shelf seawater was progressively flushed by deep north atlantic water

rare earth elements and neodymium isotopes in ferromanganese oxide coatings of cenozoic foraminifera from the atlantic ocean abstract an evaluation has been made of the method of establishing the ree contents and patterns and nd isotopic compositions of sea water over cenozoic time from their record in the femn oxide coatings of foraminiferal calcite using 0 60 ma samples from the rio grande rise dsdp site 357 it has been established that the ree contents of the coatings are generally similar to those of recent samples however in the cenozoic samples the surface coatings have been diagenetically modified under suboxic conditions resulting in a distinctly different ree pattern although the original 143 nd 144 nd ratios appear to have been preserved the nd isotopic curve for cenozoic sea water in the s atlantic shows clear temporal trends although these are not so extreme as to show 143 nd 144 nd ratios outside the range observed in modem sea water with the principal exception of the oldest samples there is an approximate inverse relationship between the nd and sr isotopic compositions of the foraminifera it is suggested that the changes reflect both global changes in the relative proportions of nd and sr derived from continental input and from the weathering of volcanic debris together with short term and local variations to which the sr curve is insensitive reflecting the different response times of the two elements to changes in oceanic input functions the nd isotope curve appears to be a potentially useful tracer of ocean palaeochemistry

numerical models for mixing corrosion in natural and artificial karst environments 1 the enlargement of initially small fractures in a karst aquifer by chemical dissolution is studied flow in the aquifer is driven by head differences between sinks and resurgences and flow depends on the permeability of small fissures and fractures in the aquifer enlargement of fractures is controlled by the chemical composition of the recharge as water undersaturated with respect to calcite is able to dissolve material from the fracture walls as fractures are enlarged with time permeability within the aquifer increases significantly and flow becomes very heterogeneous two different processes are considered enlargement due to normal corrosion where water is undersaturated with respect to calcite and enlargement due to mixing corrosion where two solutions saturated with respect to calcite but with different carbon dioxide concentrations mix and the resulting solution becomes undersaturated again the importance of mixing corrosion is discussed for two boundary conditions a natural karst aquifer is modeled with fixed recharge boundary conditions representing sinking streams and an artificial karst aquifer is simulated with fixed head boundary conditions representing a reservoir in both cases mixing corrosion is important especially if recharge is characterized by an almost saturated chemistry mixing corrosion significantly changes the evolving passage pattern as dissolution due to mixing of solutions is possible deep in the aquifer mixing corrosion also reduces breakthrough times of the aquifer and can result in dramatic leakage underneath dam sites even if the impounded water is almost saturated with respect to calcite

cerium a chemical tracer for paleo oceanic redox conditions abstract the ce anomalies found in marine carbonates provide a sensitive indicator for the study of paleo oceanic redox conditions the dependency of cce the observed ce concentration and cepo04 the activity of the cepo4 complex to the po2 ph and pco2 of seawater can be used for deciphering some aspects of the paleo ocean chemistry and is log c ce log cepo 0 4 13 2 0 25 log p o 2 3 0 ph 1 95 0 25 log p o 2 1 50 log p co 2 1 50 log ca the ph which is related to pco2 and po2 are major factors for controlling the ce concentration in seawater therefore ce anomalies ceas ce observed ce interpolated between la and pr or nd serve as indicators for ph or pco2 or po2 changes nearly uniform ce abundances found in pacific 5000 m water columns piepgras and jacobsen 1988 and the ceas in ichthyoliths can be explained using this model a general cea shift in sediments from d s d p holes 525a 530a b 516 516f suggest that the entire south atlantic water redox condition changed from reducing to oxidizing at 56 my in the north atlantic the galicia margin samples show a redox change between 132 148 my indicating active surface currents between the atlantic ocean and the shallow sea off the iberian peninsula the carbonate samples from d s d p hole 316 in the central pacific yielded an average cea of 0 15 0 01 which is 2 3 the ceas observed in deep pacific seawater by piepgras and jacobsen 1988 the relative enrichment of ce in these samples is ascribed to coprecipitation of ce oh 4 onto fe mn o coatings the striking similarities in the trace element profiles of ree sc hf th and ceas and the low u abundances 0 08 ppm in many marine carbonates indicate insignificant ce redox and trace elemental concentration changes for the pacific ocean over the past 95 my no significant ce redox change occurred in the pacific ocean within k t boundary one 240 my china limestone deposited under oxic sedimentary conditions yielded a cea of 0 53 calculations indicate a pco2 of 1 9 present value prevailed over the 240 my tethyan ocean u th ratios and low u concentrations are diagnostic indicators for obtaining reliable ceas in marine carbonates and perhaps for biogenic apatites and conodonts as well

karstification of an aquifer along the birs river switzerland a modeling approach abstract the impact caused by a construction of a dam site on the birs river close to basel switzerland on the evolution of a gypsum karst aquifer in the vicinity of the hydraulic building is studied several sinkholes provoked subsidence of the dam and the highway nearby extensive technical measures had to be conducted in order to prevent further karstification the numerous geophysical and geological field studies executed in the area together with a 3d hydrogeological model of the aquifer provide a very detailed information about the boundary conditions and the local properties determining the karstification in this work we present a 2d karst evolution model of the aquifer in the vicinity of the dam structure in contrast to older studies this time the focus of the research is not the basic processes governing the karst evolution but modeling the temporal development of the real aquifer using the large amount of information about the location we demonstrate that a detailed knowledge of the local properties of the rock hydraulic conductivity solubility is of crucial importance when modeling real aquifers from a wide range of possible evolution scenarios we deduce a warning that solutional features such as sinkholes can develop far away from the hydraulic structure and endanger facilities at the surface our model is able to reproduce and successfully explain the main geological features revealed by field studies we suggest a workflow to combine the data from field observations groundwater modeling and karst evolution modeling and to study the karstification of real aquifers we propose a scenario for the evolution of the aquifer and a reasonable range for the values of the basic parameters governing the karstification

devonian cretaceous repeated subsidence and uplift along the teisseyre tornquist zone in se poland insight from seismic data interpretation abstract the teisseyre tornquist zone that separates the east european craton from the palaeozoic platform forms one of the most fundamental lithospheric boundaries in europe devonian to cretaceous paleogene evolution of the se segment of this zone was analyzed using high quality seismic reflection data that provided detailed information regarding entire palaeozoic and mesozoic sedimentary cover with particular focus on problems of late carboniferous and late cretaceous paleogene basin inversion and uplift two previously proposed models of development and inversion of the devonian carboniferous lublin basin seem to only partly explain configuration of this sedimentary basin a new model includes late devonian early carboniferous reverse faulting within the cratonic area ne from the kock fault zone possibly first far field effect of the variscan orogeny this was followed by late carboniferous inversion of the lublin basin inversion tectonics was associated with strike slip movements along the ursynow kazimierz fault zone and thrusting along the kock fault zone possibly triggered by deeper strike slip movements late carboniferous inversion related deformations along the ne boundary of the lublin basin were associated with some degree of ductile quasi diapiric deformation facilitated by thick series of silurian shales during mesozoic extension and development of the mid polish trough major fault zones within the lublin basin remained mostly inactive and subsidence centre moved to the sw towards the nowe miasto zawichost fault zone and further to the sw into the present day holy cross mts area late cretaceous paleogene inversion of the mid polish trough and formation of the mid polish swell was associated with reactivation of inherited deeper fault zones and included also some strike slip faulting the study area provides well documented example of the foreland plate within which repeated basin inversion related to compressive transpressive deformations was triggered by active orogenic processes at the plate margin i e variscan or carpathian orogeny and involved important strike slip reactivation of crustal scale inherited fault zones belonging to the teisseyre tornquist zone

three dimensional seismic modelling of the crustal structure between east european craton and the carpathians in se poland based on celebration 2000 data summary in this paper we present results of 3 d first arrival tomography applied to data recorded in se poland during the celebration 2000 seismic experiment the target area covers ca 500 500 km 2 and represents a complex geological setting from old precambrian platform east european craton eec through the crustal blocks terranes that form the transeuropean suture zone tesz to the young alpine orogen the carpathians contrasting velocity distributions in various geological units makes the tomographic inversion challenging for this reason much attention was paid to the inversion methodology we tested multioffset and multiscale approaches by increasing the offset range in the multioffset inversion we have independently constrained different depth ranges of our model we have found that the multiscale method that is the gradual stepping from bigger to smaller model cells produced the preferred solution resolution of the resultant crustal model was determined by performing checkerboard and restoration resolution tests lateral resolution of the order of 25 km is inferred down to 10 km depth and 50 km down to 25 30 km depth we have also applied a quasi monte carlo analysis to determine the absolute errors of model parameters which to our knowledge is the first such attempt in case of a 3 d wide angle data set the mean uncertainties of our tomographic velocities are 0 1 km s 1 but some anomalies are recovered with

seismic and geological structure of the crust in the transition from baltica to palaeozoic europe in se poland celebration 2000 experiment profile cel02 abstract the celebration 2000 together with the earlier polonaise 97 deep seismic sounding experiments was aimed at the recognition of crustal structure in the border zone between the precambrian east european craton baltica and palaeozoic europe the cel02 profile of the celebration family is a 400 km long sw ne transect running in poland from the upper silesia block usb across the malopolska block mb and the trans european suture zone tesz to the east european craton eec the structure along cel02 was interpreted using both 2d tomography and forward ray tracing techniques as well as 2d gravity modelling the crustal thickness along cel02 varies from 32 35 km in the usb to 45 47 km beneath the tesz and the eec the usb is a clearly distinctive crustal block with the characteristic high velocity lower crust 7 1 7 2 km s interpreted as a fragment of gondwana the krakow lubliniec fault is a terrane boundary produced by soft docking of the usb with the mb the malopolska crust fundamentally differs from the usb and has a strong connection with baltica it is a transitional 150 to 200 km wide unit composed of the extended baltican lower crust and the overlying low velocity 5 15 5 9 km s neoproterozoic metasediments in the up to 18 km thick upper crust the ysogory unit has its crustal structure identical with that of malopolska thus it is connected with baltica and cannot be interpreted as a gondwana derived terrane higher velocity and density bodies found below the mazovia lublin graben at a depth of 12 km and at the base of the lower crust might be a result of mantle derived mafic intrusions accompanying the extension of baltica by the preliminary 2d gravity modelling we have reconfirmed the need for considering the increased tesz mantle density in comparison to the eec and usb mantle

crustal and upper mantle structure of the western carpathians from celebration 2000 profiles cel01 and cel04 seismic models and geological implications summary celebration 2000 was a large international experiment that focused on the lithospheric structure in central europe it consisted of several wide angle reflection and refraction seismic profiles profiles cel01 and cel04 are located in the transition from the precambrian and palaeozoic platforms to the carpathian orogen the data were modelled using 2 d tomographic and forward modelling techniques the profile cel01 about 900 km long extends from the southwestern margin of the east european craton to the pannonian basin system the depth of moho boundary varies along the profile from 27 33 km under the pannonian basin system area 30 39 under the carpathians and within the tesz to 40 45 km under the east european craton the cel04 profile 630 km long starts in the polish trough pt and reaches the pannonian basin system along the cel04 profile the moho interface shallows from 40 km beneath the pt to about 35 km in the maopolska unit the crustal thickness is 43 km beneath the carpathians and 25 km beneath the pannonian basin system the results obtained are consistent with a commonly accepted view of the carpathians thought to be formed largely due to the interplay between palaeogene to middle miocene subduction of oceanic or suboceanic crust and subsequent collision a feature that we interpret as the subduction related orogenic root is at least partially preserved in both profiles and is manifested by a crustal thicknesses of 39

constraints in using cerium anomaly of bulk sediments as an indicator of paleo bottom water redox environment a case study from the central indian ocean basin abstract the total rare earth elements ree abundance along with major and a range of trace element chemistry of twenty eight sub sections in a 5 m long sediment core aas 05 gc 02 from the central indian ocean basin shows a distinct ree fractionation sediments from the top 1 m of the core have comparatively low ree abundance close to average shale with a sample shale ree ratio very close to 1 strongly suggesting a dominantly terrigenous source the down core ree abundance shows a nearly two fold increase ree 167 341 ppm with depth and the ree strongly co varies with mn ti p and smectite inter element correlations and the shale normalized ree patterns suggest that light middle and heavy ree are selectively carried by terrigenous mn oxide and authigenic phosphate phases respectively suggesting a distinct ree fractionation these fractionation effects become more pronounced with increasing depth in the core the cerium ce anomaly in marine sediments is used as one of the promising tools to trace paleo bottom water redox conditions and this varies in the sediments from 0 10 to 0 08 the ce anomaly in general is positive in the top 4 m but the top 1 m have higher ce anomaly mn ti and ce ti suggest sediment deposition relatively under more oxic bottom water condition the negative ce anomaly between 4 and 5 m depth which could be interpreted to indicate a suboxic anoxic environment the redox environment inferred by the ce anomaly is compared to a number of other redox sensitive parameters to test its reliability these include mn content total organic carbon u th authigenic uranium cu zn and v cr ratio that all suggestive of deposition of sediments under oxygenated bottom water condition thus the negative ce anomaly observed between 4 and 5 m core depth does not represent a suboxic anoxic environment but is more likely due to the retention of a negative ce anomaly caused by authigenic phosphate and authigenic fe rich smectite which is formed by the reaction between iron oxyhydroxide and biogenic opal suggests an early diagenetic process and is in equilibrium with seawater ree early diagenetic process is responsible for the part of negative ce anomaly observed here therefore we suggest that the ce anomaly of bulk sediments as an indicator of paleo ocean bottom water redox conditions needs to be used with a caution

north eastward subduction followed by slab detachment to explain ophiolite obduction and early miocene volcanism in northland new zealand oligocene miocene models for northern new zealand involving south westward subduction to explain early miocene northland volcanism do not fit within the regional southwest pacific tectonic framework a new model is proposed which comprises a north east dipping south loyalty basin slab that retreated south westward in the eocene earliest miocene and was continuous with the north east dipping subduction zone of new caledonia in the latest oligocene the trench reached the northland passive margin which was pulled it into the mantle by the slab resulting in obduction of the northland allochthon during and after obduction the slab detached from the unsubductable continental lithosphere inducing widespread calc alkaline volcanism in northland the new model further explains contemporaneous arc volcanism along the northland plateau seamount chain and sinking of the northland basement followed by uplift and extension in northland

dissolved rare earth elements tracing lithogenic inputs over the kerguelen plateau southern ocean abstract dissolved rare earth elements rees were measured in the water masses upstream from and over the kerguelen plateau indian sector of the southern ocean upstream from the plateau the ree profiles were consistent with published data from the southern and indian oceans over the plateau a one box model yields a lithogenic nd flux from the dissolution of lithogenic material of 89 20 t nd y 1 and a corresponding dissolved iron input larger than 100 000 t fe y 1 however despite evidence of this significant lithogenic input dissolved fe is strongly depleted in the upper layers contrasting with the enriched ree concentrations this contrast stresses the different behaviours of ree and iron in the surface waters and the fact that strong fertilization does not imply dissolved fe replete waters

detailed tectonic evolution of the reykjanes ridge during the past 15 ma 1 we present a new detailed tectonic model of the reykjanes ridge which examines the rift propagation hypothesis for the v shaped ridges and its asymmetric lithospheric accretion four major southward rift propagations extend through our entire survey area and several additional small scale rift propagations are observed including northward propagators if plume pulses only drive southward propagators then two different driving mechanisms for propagators must exist there is a major difference in the crustal accretion asymmetry between the area immediately off the iceland shelf and that farther south both in rift propagation pattern and free air gravity lineations furthermore we identify two small offset features coined ponsu transforms from which rift propagation is both initiated and stopped the pattern of the v shaped ridges on the reykjanes ridge is not symmetric about the reykjanes ridge and the v shaped ridges are not linear continuous features our rift propagation model produces excellent fits to magnetic data and provides a self consistent model for the evolution of the reykjanes ridge during the past 15 ma

mesozoic lower jurassic red stromatactis limestones from the southern alps arzo switzerland calcite mineral authigenesis and syneresis type deformation the broccatello lithological unit lower jurassic hettangian to lower parts of upper sinemurian near the village of arzo southern alps southern switzerland is a mound shaped carbonate deposit that contains patches of red stromatactis limestone within the largely bioclastic broccatello unit the stromatactis limestone is distinguished by its early diagenetic cavity system a relatively fine grained texture and an in situ assemblage of calcified siliceous sponges various demosponges and hexactinellids a complex shallow subsurface diagenetic pathway can be reconstructed from sediment petrography in combination with comparative geochemical analysis carbon and oxygen isotopes trace and rare earth elements ree y this pathway includes organic matter transformation aragonite and skeletal opal dissolution patchy calcification and lithification sediment shrinkage sagging and collapse partial ree remobilization and multiple sediment infiltration these processes occurred under normal marine essentially oxic conditions and were independent from local recurring syn sedimentary faulting it is concluded that the stromatactis results from a combination of calcite mineral authigenesis and syneresis type deformation the natural stromatactis phenomenon may thus be best explained by maturation processes of particulate polymer gels expected to form in fine grained carbonate sediments in the shallow subsurface conditions favorable for the evolution of stromatactis appear to be particularly frequent during drowning of tropical or subtropical carbonate platforms

rare earth and trace elements of microbialites in upper jurassic coral and sponge microbialite reefs major trace y zr pb th and u rare earth element ree and sm nd isotope analyses were carried out on microbialites and detrital carbonate sediments collected in upper jurassic coral and sponge microbialite reef settings selected bioconstructions developed in various palaeogeographic settings and depositional environments on northwestern tethys and eastern atlantic margins pure carbonate lagoon carbonate dominated deep shelf to epicontinental basin and mixed carbonate siliciclastic shallow ramp and lagoon the proximity to terrigenous sources directly controlled ree patterns of carbonate samples lateral and intrareef sediments and to a lesser degree stromatolitic microbial crusts are more susceptible to contamination by terrigenous material than are microbialites of thrombolitic fabric in mixed carbonate siliciclastic settings microbialites display a flat shale normalized ree pattern in pure carbonate lagoonal settings microbialites have shale normalized ree patterns similar to those of modern seawaters with a negative ce anomaly ce ce up to 0 14 positive la and gd anomalies and light ree depletion relative to heavy ree these data imply that similar ree chemistry than modern seawater already occurred on the northwestern tethys margin at the upper jurassic strong negative ce anomalies b0 4 imply microbialite formation in well oxygenated seawaters both in coral reefs of pure carbonate lagoonal environments pagny sur meuse and sponge bioherms of deep shelf settings plettenberg absence of positive ce anomalies rules out an influence of alkaline and high ph seawaters thus ree patterns and nd isotopic signatures which are in perfect agreement with existing results for tethysian seawater confirm that microbialites can be used as proxies of palaeoenvironmental seawater chemical characteristics