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Sample records for khaki-ye kamyab ree

  1. Dr. Eberhard Rees

    NASA Technical Reports Server (NTRS)

    1970-01-01

    Dr. Eberhard Rees served as director of the Marshall Space Flight Center from March 1, 1970 until January 19, 1973 when he retired from NASA. Prior to his appointment as Director, Rees served as the Center's deputy director under Dr. Wernher von Braun, 1960-1970. Rees came to the United States as part of the Dr. Wernher von Braun's German Rocket team following World War II. He transferred to Huntsville, Alabama from Fort Bliss, Texas in 1950 to work for the Army's rocket program at Redstone Arsenal. From 1956 to 1960 he served as deputy director of development operations at the Army Ballistic Missile Agency under von Braun. In 1960 Rees was transferred to NASA's Marshall Center.

  2. Mantle metasomatism: the REE story.

    USGS Publications Warehouse

    Wilshire, H.G.

    1984-01-01

    Refractory rocks with light REE/heavy REE ratios > chondrites are common as xenoliths in basalts and kimberlites and are found in some oceanic peridotite massifs. Structural and major-element geochemical evidence from these rocks suggest that the metasomatic effects resulting in addition of light REE are local and are related to emplacement of partial melts. The melts are represented by dykes of pyroxenites, hydrous minerals and gabbro that were emplaced in mantle peridotites of various origins. Metasomatic interaction between dykes and peridotite wall rock results in light REE enrichment in peridotite and depletion in dykes relative to the original liquid. Differentiation of the intrusions and separation of residual liquids may further enhance the REE exchange and extend the volume of metasomatized peridotite. Differences in the relative abundances of altered peridotite in xenoliths and massifs are seen as a sampling problem rather than a difference in process.-L.diH.

  3. Gender- and Age-Specific REE and REE/FFM Distributions in Healthy Chinese Adults

    PubMed Central

    Cheng, Yu; Yang, Xue; Na, Li-Xin; Li, Ying; Sun, Chang-Hao

    2016-01-01

    Basic data on the resting energy expenditure (REE) of healthy populations are currently rare, especially for developing countries. The aims of the present study were to describe gender- and age-specific REE distributions and to evaluate the relationships among glycolipid metabolism, eating behaviors, and REE in healthy Chinese adults. This cross-sectional survey included 540 subjects (343 women and 197 men, 20–79 years old). REE was measured by indirect calorimetry and expressed as kcal/day/kg total body weight. The data were presented as the means and percentiles for REE and the REE to fat-free mass (FFM) ratio; differences were described by gender and age. Partial correlation analysis was used to analyze the correlations between REE, tertiles of REE/FFM, and glycolipid metabolism and eating behaviors. In this study, we confirmed a decline in REE with age in women (p = 0.000) and men (p = 0.000), and we found that men have a higher REE (p = 0.000) and lower REE/FFM (p = 0.021) than women. Furthermore, we observed no associations among glycolipid metabolism, eating behaviors, and REE in healthy Chinese adults. In conclusion, the results presented here may be useful to clinicians and nutritionists for comparing healthy and ill subjects and identifying changes in REE that are related to aging, malnutrition, and chronic diseases. PMID:27598192

  4. REE Partitioning in Lunar Minerals

    NASA Technical Reports Server (NTRS)

    Rapp, J. F.; Lapen, T. J.; Draper, D. S.

    2015-01-01

    Rare earth elements (REE) are an extremely useful tool in modeling lunar magmatic processes. Here we present the first experimentally derived plagioclase/melt partition coefficients in lunar compositions covering the entire suite of REE. Positive europium anomalies are ubiquitous in the plagioclase-rich rocks of the lunar highlands, and complementary negative Eu anomalies are found in most lunar basalts. These features are taken as evidence of a large-scale differentiation event, with crystallization of a global-scale lunar magma ocean (LMO) resulting in a plagioclase flotation crust and a mafic lunar interior from which mare basalts were subsequently derived. However, the extent of the Eu anomaly in lunar rocks is variable. Fagan and Neal [1] reported highly anorthitic plagioclase grains in lunar impact melt rock 60635,19 that displayed negative Eu anomalies as well as the more usual positive anomalies. Indeed some grains in the sample are reported to display both positive and negative anomalies. Judging from cathodoluminescence images, these anomalies do not appear to be associated with crystal overgrowths or zones.

  5. Regulation of sialidase production in Clostridium perfringens by the orphan sensor histidine kinase ReeS.

    PubMed

    Hiscox, Thomas J; Harrison, Paul F; Chakravorty, Anjana; Choo, Jocelyn M; Ohtani, Kaori; Shimizu, Tohru; Cheung, Jackie K; Rood, Julian I

    2013-01-01

    Clostridium perfringens is ubiquitous in nature and is often found as a commensal of the human and animal gastrointestinal tract. It is the primary etiological agent of clostridial myonecrosis, or gas gangrene, a serious infection that results in extensive tissue necrosis due to the action of one or more potent extracellular toxins. α-toxin and perfringolysin O are the major extracellular toxins involved in the pathogenesis of gas gangrene, but histotoxic strains of C. perfringens, such as strain 13, also produce many degradative enzymes such as collagenases, hyaluronidases, sialidases and the cysteine protease, α-clostripain. The production of many of these toxins is regulated either directly or indirectly by the global VirSR two-component signal transduction system. By isolating a chromosomal mutant and carrying out microarray analysis we have identified an orphan sensor histidine kinase, which we have named ReeS (regulator of extracellular enzymes sensor). Expression of the sialidase genes nanI and nanJ was down-regulated in a reeS mutant. Since complementation with the wild-type reeS gene restored nanI and nanJ expression to wild-type levels, as shown by quantitative reverse transcription-PCR and sialidase assays we concluded that ReeS positively regulates the expression of these sialidase genes. However, mutation of the reeS gene had no significant effect on virulence in the mouse myonecrosis model. Sialidase production in C. perfringens has been previously shown to be regulated by both the VirSR system and RevR. In this report, we have analyzed a previously unknown sensor histidine kinase, ReeS, and have shown that it also is involved in controlling the expression of sialidase genes, adding further complexity to the regulatory network that controls sialidase production in C. perfringens.

  6. Regulation of Sialidase Production in Clostridium perfringens by the Orphan Sensor Histidine Kinase ReeS

    PubMed Central

    Hiscox, Thomas J.; Harrison, Paul F.; Chakravorty, Anjana; Choo, Jocelyn M.; Ohtani, Kaori; Shimizu, Tohru

    2013-01-01

    Clostridium perfringens is ubiquitous in nature and is often found as a commensal of the human and animal gastrointestinal tract. It is the primary etiological agent of clostridial myonecrosis, or gas gangrene, a serious infection that results in extensive tissue necrosis due to the action of one or more potent extracellular toxins. α-toxin and perfringolysin O are the major extracellular toxins involved in the pathogenesis of gas gangrene, but histotoxic strains of C. perfringens, such as strain 13, also produce many degradative enzymes such as collagenases, hyaluronidases, sialidases and the cysteine protease, α-clostripain. The production of many of these toxins is regulated either directly or indirectly by the global VirSR two-component signal transduction system. By isolating a chromosomal mutant and carrying out microarray analysis we have identified an orphan sensor histidine kinase, which we have named ReeS (regulator of extracellular enzymes sensor). Expression of the sialidase genes nanI and nanJ was down-regulated in a reeS mutant. Since complementation with the wild-type reeS gene restored nanI and nanJ expression to wild-type levels, as shown by quantitative reverse transcription-PCR and sialidase assays we concluded that ReeS positively regulates the expression of these sialidase genes. However, mutation of the reeS gene had no significant effect on virulence in the mouse myonecrosis model. Sialidase production in C. perfringens has been previously shown to be regulated by both the VirSR system and RevR. In this report, we have analyzed a previously unknown sensor histidine kinase, ReeS, and have shown that it also is involved in controlling the expression of sialidase genes, adding further complexity to the regulatory network that controls sialidase production in C. perfringens. PMID:24023881

  7. REE/Fe variations in hydrothermal sediments: Implications for the REE content of seawater

    SciTech Connect

    Olivarez, A.M.; Owen, R.M. )

    1989-03-01

    Seafloor hydrothermal vent solutions exhibit rare earth element (REE) enrichments ranging between one to three orders of magnitude greater than average seawater. To assess the impact of these hydrothermal inputs on ocean chemistry, the authors have examined he behavior of REEs for hydrothermal sediments collected adjacent to two Pacific spreading ridge sites: the East Pacific Rise at 19{degree}S, and the Southern Juan de Fuca Ridge at 45{degree}N. In general, the REE/Fe ratios for both proximal and distal hydrothermal sediments are greater than vent solutions by a factor of 2 to 500, and these ratios increase with increasing distance away from the ridge axis. An evaluation of these results in the context of previous models of REE behavior indicates that, in fact, seawater experiences a net depletion in REEs as a result of hydrothermal activity. This is due primarily to the large scavenging capacity of iron oxyhydroxides which precipitate from these solutions. Such an interpretation explains why the REE content of seawater collected in the vicinity of hydrothermal vents is anomalously lower than normal seawater sampled from a comparable depth.

  8. REE in the Great Whale River estuary, northwest Quebec

    NASA Technical Reports Server (NTRS)

    Goldstein, Steven J.; Jacobsen, Stein B.

    1988-01-01

    A report on REE concentrations within the estuary of the Great Whale River in northwest Quebec and in Hudson Bay is given, showing concentrations which are less than those predicted by conservative mixing of seawater and river water, indicating removal of REE from solution. REE removal is rapid, occurring primarily at salinities less than 2 percent and ranges from about 70 percent for light REE to no more than 40 percent for heavy REE. At low salinity, Fe removal is essentially complete. The shape of Fe and REE vs. salinity profiles is not consistent with a simple model of destabilization and coagulation of Fe and REE-bearing colloidal material. A linear relationship between the activity of free ion REE(3+) and pH is consistent with a simple ion-exchange model for REE removal. Surface and subsurface samples of Hudson Bay seawater show high REE and La/Yb concentrations relative to average seawater, with the subsurface sample having a Nd concentration of 100 pmol/kg and an epsilon(Nd) of -29.3; characteristics consistent with river inputs of Hudson Bay. This indicates that rivers draining the Canadian Shield are a major source of nonradiogenic Nd and REE to the Atlantic Ocean.

  9. Genesis of ion-adsorption type REE ores in Thailand

    NASA Astrophysics Data System (ADS)

    Sanematsu, K.; Yoshiaki, K.; Watanabe, Y.

    2012-04-01

    Ion-adsorption type REE deposits, which have been economically mined only in southern China, are predominant supply sources for HREE in the world. The ore bodies consist of weathered granites called ion-adsorption ores. The majority of REE (>50 %) are electrostatically adsorbed onto weathering products in the ores and they can be extracted by ion exchange using an electrolyte solution (e.g., ammonium sulfate solution). Recently the occurrences of ion-adsorption ores have been reported in Indochina, SE Asia. In this study, we discuss geochemical and mineralogical characteristics of parent granites and weathered granites in Thailand in order to reveal the genesis of ion-adsorption ores. Permo-Triassic and Cretaceous-Paleogene granite plutons are distributed from northern Thailand to western Indonesia through eastern Myanmar and Peninsular Malaysia. They are mostly ilmenite-series calcalkaline biotite or hornblende-biotite granites. REE contents of the granites range from 60 to 600 ppm and they are relatively high in Peninsula Thailand. REE-bearing minerals consist mainly of apatite, zircon, allanite, titanite, monazite and xenotime. Some I-type granites contain REE fluorocarbonate (probably synchysite-(Ce)) in cavities and cracks in feldspars and it is the dominant source of REE for ion-adsorption ores because the fluorocarbonate is easily soluble during weathering. In contrast, insoluble monazite and xenotime are not preferable for ion-adsorption ores although they are common ore minerals of placer REE deposits. Weathered granites show REE contents ranging from 60 to 1100 ppm in Thailand because REE are relatively immobile compared with mobile elements (e.g., Na, K, Ca). In the weathered granites, REE are contained in residual minerals and secondary minerals and are adsorbed onto the surface of weathering products. A weathering profile of granite with ion-adsorption type mineralization can be divided into upper and lower parts based on REE enrichment and Ce

  10. Crystal-chemistry and partitioning of REE in whitlockite

    NASA Technical Reports Server (NTRS)

    Colson, R. O.; Jolliff, B. L.

    1993-01-01

    Partitioning of Rare Earth Elements (REE) in whitlockite is complicated by the fact that two or more charge-balancing substitutions are involved and by the fact that concentrations of REE in natural whitlockites are sufficiently high such that simple partition coefficients are not expected to be constant even if mixing in the system is completely ideal. The present study combines preexisting REE partitioning data in whitlockites with new experiments in the same compositional system and at the same temperature (approximately 1030 C) to place additional constraints on the complex variations of REE partition coefficients and to test theoretical models for how REE partitioning should vary with REE concentration and other compositional variables. With this data set, and by combining crystallographic and thermochemical constraints with a SAS simultaneous-equation best-fitting routine, it is possible to infer answers to the following questions: what is the speciation on the individual sites Ca(B), Mg, and Ca(IIA) (where the ideal structural formula is Ca(B)18 Mg2Ca(IIA)2P14O56); how are REE's charge-balanced in the crystal; and is mixing of REE in whitlockite ideal or non-ideal. This understanding is necessary in order to extrapolate derived partition coefficients to other compositional systems and provides a broadened understanding of the crystal chemistry of whitlockite.

  11. Battery related cobalt and REE flows in WEEE treatment.

    PubMed

    Sommer, P; Rotter, V S; Ueberschaar, M

    2015-11-01

    In batteries associated with waste electrical and electronic equipment (WEEE), battery systems can be found with a higher content of valuable and critical raw materials like cobalt and rare earth elements (REE) relative to the general mix of portable batteries. Based on a material flow model, this study estimates the flows of REE and cobalt associated to WEEE and the fate of these metals in the end-of-life systems. In 2011, approximately 40 Mg REE and 325 Mg cobalt were disposed of with WEEE-batteries. The end-of-life recycling rate for cobalt was 14%, for REE 0%. The volume of waste batteries can be expected to grow, but variation in the battery composition makes it difficult to forecast the future secondary raw material potential. Nevertheless, product specific treatment strategies ought to be implemented throughout the stages of the value chain.

  12. REE in karst bauxites: the Campania example (southern Italy)

    NASA Astrophysics Data System (ADS)

    Mondillo, N.; Boni, M.; Balassone, G.; Rollinson, G.

    2012-04-01

    Global production of Rare Earth Element (REE) has dramatically increased in the last years, hence the strong interest to identify new deposits and to understand the processes responsible for their formation. Among REE concentrations related to weathering, the current targets are represented by the ion-adsorption deposit-types, occurring in China, in which REEs are adsorbed onto the surface of clays. Laterites have been also intensively investigated since the discovery of the secondary deposit of Mount Weld (Australia). Most REEs behave as immobile elements in laterites, and tend to be enriched compared to the underlying parent rocks. Many authors debate on a possible REE fractionation along the laterite profiles, resulting in the formation of supergene LREE-minerals. Bauxites are economic Al accumulations, derived from the weathering of alumosilicate-rich parent rocks resulting in the development of laterite profiles. Components as Ca, Mg, K, Si are leached and residual Fe, Al and Ti precipitate in form of hematite>>goethite, gibbsite [Al(OH)3] or amorphous Al hydroxides and anatase. Metabauxites can contain boehmite or diaspore [AlO(OH)]. Chemical composition (including REEs content) of lateritic bauxites generally mirrors the original composition of the parent rock. Geochemistry of REEs in karst bauxites, which lay on carbonate bedrocks and may be also allochthonous to them, is not so straightforward. Cretaceous karst bauxite deposits in the Apennine chain (Southern Italy) are presently uneconomic. A full mineralogical and geochemical study has been performed on several deposits of the Campania district, and three representative profiles have been sampled. In all deposits the bauxite ore has an oolitic-pisolitic texture, but contains also detrital intervals. The mineral association consists of boehmite, kaolinite and hematite, with less goethite and anatase. The main REE-bearing mineral is detrital monazite. In detail, we could detect (SEM) other LREE

  13. REE and Strontium Partition Coefficients for Nakhla Pyroxenes

    NASA Technical Reports Server (NTRS)

    Oe, K.; McKay, G.; Le, L.

    2001-01-01

    We present new partition coefficients for REE and Sr determined using a synthetic melt that crystallizes pyroxenes very similar in composition to Nakhla pyroxene cores. We believe these are the most appropriate partition coefficients to use in studying Nakhla Additional information is contained in the original extended abstract..

  14. REE Abundances in Matrix of Allende (CV) Chondrite

    NASA Astrophysics Data System (ADS)

    Inoue, M.; Nakamura, N.; Kimura, M.

    1996-03-01

    In order to examine trace element distributions in matrix material of primitive chondrites, four interchondrule matrix specimens (sample weight ~100 micrograms) were carefully excavated using a microdrill from the petrographically characterized areas of the published sections of Allende (CV) chondrite and were precisely analyzed for REE, Ba, Sr, Rb, K, Ca and Mg by direct loading isotope dilution method (DL-IDMS).

  15. Vapour transport of rare earth elements (REE) in volcanic gas: Evidence from encrustations at Oldoinyo Lengai

    NASA Astrophysics Data System (ADS)

    Gilbert, C. D.; Williams-Jones, A. E.

    2008-10-01

    Fumarolic encrustations and natrocarbonatite lava from the active crater of Oldoinyo Lengai volcano, Tanzania, were sampled and analysed. Two types of encrustation were distinguished on the basis of their REE content, enriched (~ 2800-5600 × [REE chondrite]) and depleted (~ 100-200 × [REE chondrite]) relative to natrocarbonatite (1700-1900 × [REE chondrite]. REE-enriched encrustations line the walls of actively degassing fumaroles, whereas REE-depleted encrustations occur mainly along cracks in and as crusts on cooling natrocarbonatite lava flows; one of the low REE encrustation samples was a stalactite from the wall of a possible fumarole. The encrustations are interpreted to have different origins, the former precipitating from volcanic gas and the latter from meteoric/ground water converted to steam by the heat of the overlying lava flow(s). REE-profiles of encrustations and natrocarbonatite are parallel, suggesting that there was no preferential mobilization of specific REE by either volcanic vapour or meteoric water vapour. The elevated REE-content of the first group of encrustations suggests that direct REE-transport from natrocarbonatite to volcanic vapour is possible. The REE trends observed in samples precipitating directly from the volcanic vapour cannot be explained by dry volatility based on the available data as there is no evidence in the encrustation compositions of the greatly enhanced volatility predicted for Yb and Eu. The observed extreme REE-fractionation with steep La/Sm slopes parallel to those of the natrocarbonatite reflects solvation and complexation reactions in the vapour phase that did not discriminate amongst the different REE or similar transport of REE in both the natrocarbonatite magma and its exsolving vapour. The low concentrations of REE in the encrustations produced by meteoric vapour suggest that the temperature was too low or that this vapour did not contain the ligands necessary to permit significant mobilization of the REE.

  16. Effects of rare earth elements and REE-binding proteins on physiological responses in plants.

    PubMed

    Liu, Dongwu; Wang, Xue; Chen, Zhiwei

    2012-02-01

    Rare earth elements (REEs), which include 17 elements in the periodic table, share chemical properties related to a similar external electronic configuration. REEs enriched fertilizers have been used in China since the 1980s. REEs could enter the cell and cell organelles, influence plant growth, and mainly be bound with the biological macromolecules. REE-binding proteins have been found in some plants. In addition, the chlorophyll activities and photosynthetic rate can be regulated by REEs. REEs could promote the protective function of cell membrane and enhance the plant resistance capability to stress produced by environmental factors, and affect the plant physiological mechanism by regulating the Ca²⁺ level in the plant cells. The focus of present review is to describe how REEs and REE-binding proteins participate in the physiological responses in plants.

  17. The first data on the vertical REE distribution in taiga soils of the Russian Far East

    NASA Astrophysics Data System (ADS)

    Bryanin, S. V.; Sorokina, O. A.

    2015-10-01

    Coarse humic brown soils formed on different rocks under natural conditions of southern taiga of the Upper Priamur'e were studied. Concentration and distribution of REE in organic-mineral and metamorphic soil horizons were estimated. Soils inherit REE distribution in underlying rocks sitll at lower concentrations. The maximal REE concentrations are found in metamorphic soil horizon and the lowest ones in humic-accumulative. Soil formation processes have an effect on REE concentration in soils, but do not change their distribution.

  18. Rees algebras, Monomial Subrings and Linear Optimization Problems

    NASA Astrophysics Data System (ADS)

    Dupont, Luis A.

    2010-06-01

    In this thesis we are interested in studying algebraic properties of monomial algebras, that can be linked to combinatorial structures, such as graphs and clutters, and to optimization problems. A goal here is to establish bridges between commutative algebra, combinatorics and optimization. We study the normality and the Gorenstein property-as well as the canonical module and the a-invariant-of Rees algebras and subrings arising from linear optimization problems. In particular, we study algebraic properties of edge ideals and algebras associated to uniform clutters with the max-flow min-cut property or the packing property. We also study algebraic properties of symbolic Rees algebras of edge ideals of graphs, edge ideals of clique clutters of comparability graphs, and Stanley-Reisner rings.

  19. Metal loading levels influence on REE distribution on humic acid: Experimental and Modelling approach

    NASA Astrophysics Data System (ADS)

    Marsac, R.; Davranche, M.; Gruau, G.; Dia, A.

    2009-04-01

    In natural organic-rich waters, rare earth elements (REE) speciation is mainly controlled by organic colloids such as humic acid (HA). Different series of REE-HA complexation experiments performed at several metal loading (REE/C) displayed two pattern shapes (i) at high metal loading, a middle-REE (MREE) downward concavity, and (ii) at low metal loading, a regular increase from La to Lu (e.g. Sonke and Salters, 2006; Pourret et al., 2007). Both REE patterns might be related to REE binding with different surface sites on HA. To understand REE-HA binding, REE-HA complexation experiments at various metals loading were carried out using ultrafiltration combined with ICP-MS measurements, for the 14 REE simultaneously. The patterns of the apparent coefficients of REE partition between HA and the inorganic solution (log Kd) evolved regularly according to the metal loading. The REE patterns presented a MREE downward concavity at low loading and a regular increase from La to Lu at high loading. The dataset was modelled with Model VI by adjusting two specific parameters, log KMA, the apparent complexation constant of HA low affinity sites and DLK2, the parameter increasing high affinity sites binding strength. Experiments and modelling provided evidence that HA high affinity sites controlled the REE binding with HA at low metal loading. The REE-HA complex could be as multidentate complexes with carboxylic or phenolic sites or potentially with sites constituted of N, P or S as donor atoms. Moreover, these high affinity sites could be different for light and heavy REE, because heavy REE have higher affinity for these sites, in low density, and could saturate them. These new Model VI parameter sets allowed the prediction of the REE-HA pattern shape evolution on a large range of pH and metal loading. According to the metal loading, the evolution of the calculated REE patterns was similar to the various REE pattern observed in natural acidic organic-rich waters (pH<7 and DOC>10

  20. REE incorporation and behaviour in aquatic turtles as a consequence of environmental exposure and biological processes

    NASA Astrophysics Data System (ADS)

    Censi, P.; Randazzo, L. A.; D'Angelo, S.; Cuttitta, A.; Saiano, F.

    2012-04-01

    Rare Earth Elements (REE) contents in Emys trinacris have been investigated for the first time in order to recognise effects of the chemistry of the environment on the composition of biological fluids. Representing radionuclides a potential health risk for living organisms in case of incorporation in tissues and being REE geochemical analogues of actinides in hydrosphere, this study was focused on investigation of REE behaviour in whole blood and esoskeleton of selected individuals of Emys trinacris. The choice of this species is related to its amphibian character that allowed us to evidence environmental stress in terms of composition of environmental freshwaters whose REE compositions were investigated and compared with blood samples. Moreover effects induced by different environmental conditions were investigated collecting samples in two sites characterised by absence of an anthropogenic signature (GT site) and subjected to strong anthropogenic pressure in terms of wastewater input (SIC site), respectively. In both sites REE contents in whole blood samples of studied turtles are quite similar even if in GT site the highest REE contents have been recognised. Shale-normalised REE patterns show very similar REE behaviour with light REE (LREE) enrichments with respect to heavier REE (HREE), mainly in samples from anthropized site. If REE concentrations in whole blood are normalised to the composition of environmental waters, calculated REE patterns show upward concave shapes centred on Gd that are more pronounced in samples from GT site because their patterns are more enriched in LREE. The last features observed in blood samples from GT can be related to larger REE contents occurred in environmental water from this site with respect to waters collected in SIC site, suggesting that a relationship occurs between REE contents in environmental and biological fluids. Since MREE depletions were observed in waters experiencing phosphate crystallization, observed REE

  1. Expanding the REE Partitioning Database for Lunar Materials

    NASA Technical Reports Server (NTRS)

    Rapp, Jennifer F.; Draper, David S.

    2014-01-01

    Positive europium anomalies are ubiquitous in the plagioclase-rich rocks of the lunar highlands, and complementary negative Eu anomalies are found in most lunar basalts. This is taken as evidence of a large-scale differentation event, with crystallization of a global-scale lunar magma ocean (LMO) resulting in a plagioclase flotation crust and a mafic lunar interior from which mare basalts were later derived. However, the extent of the Eu anomaly in lunar rocks is variable. Some plagioclase grains in a lunar impact rock (60635) have been reported to display a negative Eu anomaly, or in some cases single grains display both positive and neagtive anomalies. Cathodoluminescence images reveal that some crystals have a negative anomaly in the core and positive at the rim, or vice versa, and the negative anomalies are not associated with crystal overgrowths. Oxygen fugacity is known to affect Eu partitioning into plagioclase, as under low fO2 conditions Eu can be divalent, and has an ionic radius similar to Ca2+ - significant in lunar samples where plagioclase compositions are predominantly anorthitic. However, there are very few experimental studies of rare earth element (REE) partitioning in plagioclase relevant to lunar magmatism, with only two plagioclase DEu measurements from experiments using lunar materials, and little data in low fO2 conditions relevant to the Moon. We report on REE partitioning experiments on lunar compositions. We investigate two lunar basaltic compositions, high-alumina basalt 14072 and impact melt breccia 60635. These samples span a large range of lunar surface bulk compositions. The experiments are carried out at variable fO2 in 1 bar gas mixing furnaces, and REE are analysed by and LA-ICP-MS. Our results not only greatly expand the existing plagioclase DREE database for lunar compositions, but also investigate the significance of fO2 in Eu partitioning, and in the interpretation of Eu anomalies in lunar materials.

  2. EXAFS study on the cause of enrichment of heavy REEs on bacterial cell surfaces

    NASA Astrophysics Data System (ADS)

    Takahashi, Yoshio; Yamamoto, Mika; Yamamoto, Yuhei; Tanaka, Kazuya

    2010-10-01

    Rare earth element (REE) pattern is a unique geochemical tracer and has been measured for various natural materials. Among these, the REE distribution pattern between bacteria and water exhibits anomalous enrichment in the heavy REE (HREE) part, which can act as a signature of bacteria-related materials in natural samples. In this study, the REE binding site on the cell surface of a Gram-positive bacterium ( Bacillus subtilis) responsible for HREE enrichment has been identified using extended X-ray absorption fine structure (EXAFS) coupled with a study of the variation in REE distribution patterns. The EXAFS data showed that the HREEs form complexes with multiple phosphate site (including phosphoester site) with a larger coordination number (CN) at lower REE-bacteria ratios ([REE]/[bac]), while light and middle REEs form complexes to the phosphate site with a lower CN. The fraction coordinated to carboxylate increased for all REEs with increasing [REE]/[bac] ratio. On the other hand, the enrichment of HREE in the REE distribution patterns of the bacteria was less marked with increasing [REE]/[bac] ratio. This result is consistent with the EXAFS data, because the REE pattern of surface complex with multiple phosphate in a reference material exhibits a monotonous increase for heavier REE, while phosphate surface complex with a low CN and a carboxylate site reach a maximum around Sm and Eu. Based on these results, it is clear that the REE are primarily bound to the phosphate site and subsequently to the carboxylate site on the bacterial cell surface. Regarding the pH dependence in the range (3 < pH < 7), both the EXAFS and REE pattern data indicate that the fraction of REE-carboxylate increased as the pH increases. The results above obtained for B. subtilis were also valid for Escherichia coli, a Gram-negative bacterium, showing that similar phosphate and carboxylate sites are also available in the cell walls of E. coli, or other Gram negative bacteria. In all our

  3. REE mobility during the alteration of Carbonatite and their economic potential.

    NASA Astrophysics Data System (ADS)

    Marien, Christian; Dijkstra, Arjan; Wilkins, Colin

    2016-04-01

    The supply risk of Rare Earth Elements is an unpredictable economic factor for the future application and development of modern technology for the EU. Therefore a better understanding of REE mobilisation during hydrothermal alteration of Carbonatites is essential for a safer supply of REE in general. The hydrothermal alteration of Carbonatite within the Fen Complex (Norway) forms a fine grained red hematized rock type, called Rødbergite, which is partially enriched in REE. The variation of REE within the Rødbergite is poorly understood and problematic for any future REE exploitation from Rødbergite. A genetic model of the formation of Rødbergite will provide more information about the economic potential of Rødbergite. The gradual transformation of carbonatite to Rødbergite is not easily observable due to sparse outcrop in the Fen Complex. A fresh road cut near the Bjørndallen farm (Fen Complex) provides a unique insight to the progressive hydrothermal alteration from carbonatite to Rødbergite and is therefore crucial for a genetic model of the formation of Rødbergite. 14 Samples were taken along the profile. The mineralogical, geochemical and textural characterization of the samples using the SEM as well as major-, trace- and isotopic elemental data revealed the breakdown of the primary minerals due to the infiltration of an oxidizing fluid along grain boundaries. The primary REE-minerals in unaltered Carbonatite are REE fluorocarbonates. With the increasing alteration to Rødbergite REE fluorocarbonates are progressively replaced by hematite. In contrast, monazite - a REE-phosphate - is the dominant REE mineral species in the Rødbergite. A transitional Rødbergite sample shows apatite aggregates with a strong preferential concentration of monazite along the rim of the apatite aggregates. This observation provides strong evidence for the solution of REE in the primary rock (carbonatite) by fluids and later precipitation of REE along phosphate bearing

  4. Geochemical and mineralogical characteristics of ion-adsorption type REE mineralization in Phuket, Thailand

    NASA Astrophysics Data System (ADS)

    Sanematsu, Kenzo; Kon, Yoshiaki; Imai, Akira; Watanabe, Koichiro; Watanabe, Yasushi

    2013-04-01

    Geochemical and mineralogical studies were conducted on the 12-m-thick weathering profile of the Kata Beach granite in Phuket, Thailand, in order to reveal the transport and adsorption of rare earth elements (REE) related to the ion-adsorption type mineralization. The parent rock is ilmenite-series biotite granite with transitional characteristics from I type to S type, abundant in REE (592 ppm). REE are contained dominantly in fluorocarbonate as well as in allanite, titanite, apatite, and zircon. The chondrite-normalized REE pattern of the parent granite indicates enrichment of LREE relative to HREE and no significant Ce anomaly. The upper part of the weathering profile from the surface to 4.5 m depth is mostly characterized by positive Ce anomaly, showing lower REE contents ranging from 174 to 548 ppm and lower percentages of adsorbed REE from 34% to 68% compared with the parent granite. In contrast, the lower part of the profile from 4.5 to 12 m depth is characterized by negative Ce anomaly, showing higher REE contents ranging from 578 to 1,084 ppm and higher percentages from 53% to 85%. The negative Ce anomaly and enrichment of REE in the lower part of the profile suggest that acidic soil water in an oxidizing condition in the upper part mostly immobilized Ce4+ as CeO2 and transported REE3+ downward to the lower part of the profile. The transported REE3+ were adsorbed onto weathering products or distributed to secondary minerals such as rhabdophane. The immobilization of REE results from the increase of pH due to the contact with higher pH groundwater. Since the majority of REE in the weathered granite are present in the ion-adsorption fraction with negative Ce anomaly, the percentages of adsorbed REE are positively correlated with the whole-rock negative Ce anomaly. The result of this study suggests that the ion-adsorption type REE mineralization is identified by the occurrence of easily soluble REE fluorocarbonate and whole-rock negative Ce anomaly of

  5. REE compositions in fossil vertebrate dental tissues indicate biomineral preservation

    NASA Astrophysics Data System (ADS)

    Žigaite, Ž.; Kear, B.; Pérez-Huerta, A.; Jeffries, T.; Blom, H.

    2012-04-01

    Rare earth element (REE) abundances have been measured in a number of Palaeozoic and Mesozoic dental tissues using Laser Ablation Inductively Coupled Plasma Mass-spectrometry (LA-ICP-MS). Fossil vertebrates analysed comprise scales and tesserae of Silurian and Devonian acanthodians, chondrichthyans, galeaspids, mongolepids, thelodonts, as well as teeth of Cretaceous lungfish and marine reptiles. The evaluation of fossil preservation level has been made by semi-quantitative spot geochemistry analyses on fine polished teeth and scale thin sections, using Energy Dispersive X-ray Spectroscopy (EDS). Fossil teeth and scales with significant structure and colour alteration have shown elevated heavy element concentrations, and the silicification of bioapatite has been common in their tissues. Stable oxygen isotope measurements (δ18O) of bulk biomineral have been conducted in parallel, and showed comparatively lower heavy oxygen values in the same fossil tissues with stronger visible alteration. Significant difference in REE concentrations has been observed between the dentine and enamel of Cretaceous plesiosaurs, suggesting the enamel to be more geochemically resistant to diagenetic overprint.

  6. Ion microprobe investigation of plagioclase and orthopyroxene from lunar Mg-suite norites: Implications for calculating parental melt REE concentrations and for assessing postcrystallization REE redistribution

    SciTech Connect

    Papike, J.J.; Fowler, G.W.; Shearer, C.K.; Layne, G.D.

    1996-10-01

    The lunar Mg-suite, which includes dunites, troctolites, and norites, makes up to 20-30% of the Moon`s crust down to a depth of {approximately}60 km. The remainder is largely anorthosite. This report focuses on norites (which consist mostly of orthopyroxene and plagioclase) because we have found that both phases are effective recorders of their parental melt compositions. In an earlier report, we analyzed orthopyroxene from twelve samples (three from Apollo 14, two from A-15, and seven from A-17) by orthopyroxene from twelve samples (three from Apollo 14, two from A-15, and seven from A-17) by SIMS for eight REE (La, Ce, Nd, Sm, Eu, Dy, Er, Yb). Inversion of these data to estimated melt compositions yielded extremely high REE concentrations similar to KREEP. In this study, we report SIMS REE data for plagioclase from these same twelve samples. The major objective of this study is to estimate parental REE concentrations from both orthopyroxene and plagioclase data to see if both data inversions produce concordant from both orthopyroxene and plagioclase data to see if both data inversions produce concordant melt compositions and thus better constrain the composition of melts parental to Mg-suite norites. The estimated REE concentrations from both phases show some evidence of slight postcrystallization REE redistribution. Comparison of the observed ratio of REE for pyroxene/plagioclase to the ratio of the Ds for pyroxene/plagioclase is consistent with REE redistribution which involves LREE diffusing from pyroxene into plagioclase and HREE diffusing from plagioclase into pyroxene. However, apparently these postcrystallization exchanges have not seriously affected our ability to estimate melt REE concentrations. 34 refs., 7 figs., 5 tabs.

  7. Direct dating and characterization of the Pope's Hill REE Deposit, Labrador

    NASA Astrophysics Data System (ADS)

    Chafe, A. N.; Hanchar, J. M.; Fisher, C.; Piccoli, P. M.; Crowley, J. L.; Dimmell, P. M.

    2012-12-01

    The Pope's Hill rare earth element (REE) trend (PHT) is located approximately 100 km southwest of Happy Valley-Goose Bay, along the Trans Labrador Highway, in central Labrador. Whole-rock geochemical analyses of the main REE-bearing unit indicate total rare earth element contents ranging from 1 to 22 weight percent (wt%) REE3+. The REE-enriched unit is hosted within a hydrothermally altered syenite, trending northeast and traceable for approximately 2.8km. Samples of ore, host rock, and country rock, were collected from throughout the trend in order to: 1) quantify which phases concentrate the REE and their abundances and distribution in the ore; and 2) use in situ LA-ICPMS and ID-TIMS U-Pb geochronology and in situ Sm-Nd isotopes using LA-MC-ICPMS in monazite from the ore and host rock to constrain the timing of mineralization and determine the source of the REE. These data will help develop predictive models for this type of mineral deposit elsewhere. The PHT is defined as the host syenite and REE-enriched segregations; two contrasting lithologies. The rare earth element minerals (REE) occur in millimeter- to centimeter-scale pods that are locally discontinuous. The REE are hosted in a variety of silicate, phosphate, carbonate, and niobate phases; with a majority hosted in allanite(-Ce), titanite(-Ce), monazite(-Ce), britholite(-Ce); and a minor percentage in REE-carbonates and fergusonite(-Nd). Both apatite and titanite occur in two different compositional forms that range in chemistry from end-member stoichiometric apatite and titanite to highly REE-enriched - apatite-britholite and titanite(-Ce), where chemical substitutions, such as Si4+ + REE3+ substitute for Ca2+ + P5+ in apatite and REE3+ + Fe3+ substitute for Ca2+ + Ti4+ in titanite in order to incorporate up to ~40 wt% REE2O3 in both minerals. The U-Pb geochronology indicate that allanite, titanite(-Ce), monazite and fergusonite crystallized from ~1060 to ~940 Ma, a period spanning ~120 Ma. Sm-Nd tracer

  8. REE speciation in low-temperature acidic waters and the competitive effects of aluminum

    USGS Publications Warehouse

    Gimeno, Serrano M.J.; Auque, Sanz L.F.; Nordstrom, D.K.

    2000-01-01

    The effect of simultaneous competitive speciation of dissolved rare earth elements (REEs) in acidic waters (pH 3.3 to 5.2) has been evaluated by applying the PHREEQE code to the speciation of water analyses from Spain, Brazil, USA, and Canada. The main ions that might affect REE are Al3+, F-, SO42-, and PO43-. Fluoride, normally a significant complexer of REEs, is strongly associated with Al3+ in acid waters and consequently has little influence on REEs. The inclusion of aluminum concentrations in speciation calculations for acidic waters is essential for reliable speciation of REEs. Phosphate concentrations are too low (10-4 to 10-7 m) to affect REE speciation. Consequently, SO42- is the only important complexing ligand for REEs under these conditions. According to Millero [Millero, F.J., 1992. Stability constants for the formation of rare earth inorganic complexes as a function of ionic strength. Geochim. Cosmochim. Acta, 56, 3123-3132], the lanthanide sulfate stability constants are nearly constant with increasing atomic number so that no REE fractionation would be anticipated from aqueous complexation in acidic waters. Hence, REE enrichments or depletions must arise from mass transfer reactions. (C) 2000 Elsevier Science B.V. All rights reserved.

  9. Partitioning in REE-saturating minerals - Theory, experiment, and modelling of whitlockite, apatite, and evolution of lunar residual magmas

    NASA Technical Reports Server (NTRS)

    Jolliff, Bradley L.; Haskin, Larry A.; Colson, Russell O.; Wadhwa, Meenakshi

    1993-01-01

    Compositions, including REEs determined by ion microprobe, of apatite and whitlockite in lunar rock assemblages rich in incompatible trace elements, are presented. Concentrations of REEs in lunar whitlockites are high, ranging from about 1.2 to 2.1 REEs (lanthanides + Y) per 56 oxygens. This slightly exceeds the level of two REE atoms per 56 oxygens at which the dominant substitution theoretically becomes saturated. This saturation effect leads to whitlockite REE(3+) D values at typical lunar whitlockite REE concentrations which are 30-40 percent lower than the D values at low concentrations. The halogen-to-phosphorous ratio in lunar melts is a key factor determining the REE distribution with crystalline assemblages. As long as P and REE concentrations of melts are in KREEP-like proportions, one or both of the phosphates will saturate in melts at similar REE concentrations.

  10. Crystallization process of zircon and fergusonite during hydrothermal alteration in Nechalacho REE deposit, Thor Lake, Canada

    NASA Astrophysics Data System (ADS)

    Hoshino, M.; Watanabe, Y.; Murakami, H.; Kon, Y.; Tsunematsu, M.

    2012-04-01

    The core samples of two drill holes, which penetrate sub-horizontal mineralized horizons at Nechalacho REE deposit in the Proterozoic Thor Lake syenite, Canada, were studied in order to clarify magmatic and hydrothermal processes that enriched HFSE (e.g. Zr, Nb, Y and REE). Zircon is the most common REE minerals in Nechalacho REE deposit. The zircon is divided into five types as follows: Type-1 zircon occurs as single grain in phlogopite and the chondrite-normalized REE pattern is characterized by a steeply-rising slope from the LREE to the HREE with a positive Ce-anomaly and negative Eu-anomaly. This chemical characteristic is similar to that of igneous zircon. Type-2 zircon consists of HREE-rich magmatic porous core and LREE-Nb-F-rich hydrothermal rim. This type zircon is mostly included in phlogopite and fluorite, and occasionally in microcline. Type-3 zircon is characterized by euhedral to anhedral crystal, occurring in a complex intergrowth with REE fluorocarbonates. Type-3 zircons have high contents of REE, Nb and fluorine. Type-4 zircon consists of porous-core and -rim zones, but their chemical compositions are similar to each other. This type zircon is a subhedral crystal rimmed by fergusonite. Type-5 zircon is characterized by smaller, porous and subhedral to anhedral crystals. The interstices between small zircons are filled by fergusonite. Type-4 and -5 zircons show low REE and Nb contents. Occurrences of these five types of zircon are different according to the depth and degree of the alteration by hydrothermal solutions rich in F- and CO3 of the two drill holes, which permit a model for evolution of the zircon crystallization in Nechalacho REE deposit as follows: (1) type-1 (single magmatic zircon) is formed in miaskitic syenite. (2) LREE-Nb-F-rich hydrothermal zircon formed around HREE-rich magmatic zircon (type-2 zircon); (3) type-3 zircon crystallized thorough F and CO3-rich hydrothermal alteration of type-2 zircon which formed the complex

  11. REE Diffusion on Quartzite Grain Boundaries: Preliminary Results from Experiments

    NASA Astrophysics Data System (ADS)

    Price, J. D.; Watson, E. B.

    2008-12-01

    Two novel experimental configurations were used to characterize REE diffusion along grain boundaries. Both configurations involve juxtaposing a concentrated REE source phase with a synthetic quartzite containing a disseminated sink phase (~5 vol. %). The quartzite was synthesized from a mixture of powdered natural quartz (22-75 μm) fired at 1000 °C and combined with polycrystalline fragments of Dy2O3 or small crystals of synthetic xenotime. These mixtures were annealed for 3 days at 1000 °C and 1GPa in nickel capsules within a piston cylinder apparatus. This produced a ~100 μm grain size quartzite containing dispersed, 10-40 μm Dy2O3 - Dy2SiO5 or xenotime particles. Polished sections of the quartzite containing the Dy-phase were paired with Pr2O3 powder, and those of the xenotime quartzite were coupled with DyPO4 powder. These diffusion couples were run in the piston cylinder at temperatures between 1000 and 1300 °C, 1 GPa pressure, for durations between 1 day and 1 week. In both the quartzite synthesis and diffusion experiments, all materials were prepared to minimize water in the materials. Cathodoluminescence imaging of the run products suggests that that REE diffusion occurs mainly along grain boundaries, with some penetration into the quartz crystals by lattice diffusion. For runs with T >1200 °C, EPMA evaluation of the sink particles reveals a decrease in concentration of the diffusant as a function of distance from the boundary. In the oxide experiments, the penetration of Pr varied from 370 μm at 1300 °C for 24 hours, to 245 μm at 1250 °C for 48 hours, to 150 μm at 1200 °C for 72 hours. In a single phosphate experiment, Dy penetrated to 240 μm at 1300 °C in 6 hours. In both types of experiments, those with T < 1200 °C have thus far failed to show measurable penetration of the diffusant for durations up to a week.

  12. A preliminary petrogenetic grid for REE fluorocarbonates and associated minerals

    NASA Astrophysics Data System (ADS)

    Williams-Jones, Anthony E.; Wood, Scott A.

    1992-02-01

    The bulk of the world's economic LREE reserves occur as fluorocarbonate minerals, notably bastnaesite. However, despite the importance of these minerals, very little is known about the physicochemical conditions controlling their formation. In this paper we attempt to partly redress this deficiency by qualitatively determining P- T and compositional relationships for part of the system Ln(CO 3)F-CaCO 3-F 2(CO 3) -1-H 2O, including the minerals fluorite, calcite, bastnaesite, parisite, synchysite and fluocerite. This degenerate ( n + 3)-phase multisystem has 23 possible base P- T topologies, plus their mirror images and trivial conjugates, from which we have been able to select a single probable stable topology using a combination of published experimental phase equilibrium data, molar volume and entropy estimates and natural assemblage data. Compositional relationships in the system have been established by constructing log ( aca2+ · aF-2) vs. log ( a F -2/a CO 32-) diagrams for each of the stable divariant regions shown on the P- T net. Important conclusions of the study with respect to P- T relationships are (1) that all of the above REE-fluorocarbonate minerals can form at comparatively low pressure and temperature; (2) that bastnaesite + fluorite is a low-temperature assemblage and, in the presence of synchysite or calcite, is also restricted to low or high pressure, respectively; (3) that parisite + fluorite is stable to higher temperatures; (4) that bastnaesite + synchysite + calcite is restricted to high P- T conditions; (5) that parisite reacts to form bastnaesite and calcite at high temperatures (<620°C at 1 kb); and (6) that bastnaesite-(La) decomposes by a decarbonation reaction at temperatures <750°C at 1 kb and at lower temperatures with decreasing ionic radius of the lanthanide. The principal conclusions with respect to compositional relationships are (1) that transformations among the REE fluorocarbonates cannot occur through changes in F

  13. Diffusion of REE, Hf and Sr in Olivine

    NASA Astrophysics Data System (ADS)

    Remmert, P.; Dohmen, R.; Chakraborty, S.

    2008-12-01

    We have determined diffusion coefficients of the rare earth elements Ce, Nd, Sm, Eu, Lu, and also of Sr and Hf, in single crystals of natural olivine at atmospheric pressure, at an oxygen fugacity of 10-5 Pa and a temperature of 1275 °C. Sources of diffusants were thin films of olivine composition doped with the relevant elements. Thin films were produced by PLD (pulsed laser deposition) and RBS (Rutherford backscattering) was used to measure thickness and stoichiometry of the films as well as to analyze the concentration profiles. The concentration profiles were numerically fitted to yield the following diffusion coefficients (D, in m2/s): log DCe: -19.61 ± 0.21; log DNd: -19.54 ± 0.11; log DSm: -19.15 ± 0.05; log DEu: -19.10; log DLu: -19.00, log DHf: -20.23 ± 0.07; log DSr: -18.7. Diffusion coefficients of the rare-earth elements increase from Ce to Lu, demonstrating the role of ionic radius in controlling diffusion because all REE are trivalent. The tetravalent and divalent cations hafnium and strontium diffuse an order of magnitude slower and faster, respectively, than the REE in olivine. This highlights the important influence of ionic charge on diffusion rates. The diffusion coefficients of the REE are slower by a few orders of magnitudes than the diffusion rate of Cr in olivine [1]. The rates found in this study are slower than those assumed by a model [2] for compositional modification of melt inclusions in olivine. Use of our data in their calculations indicates that it will take longer to modify the composition of melt inclusions in olivine (millions of years rather than thousands of years) but the fractionation of HREE from LREE will be larger. [1] Ganguly J, Ito M (2006) Geochim Cosmochim Acta, 70, 799-809. [2] Cottrell E, Spiegelman M, Langmuir CH (2002) Geochem Geophys Geosyst, doi:10.1029/2001GC000205

  14. Impact of humate complexation on the adsorption of REE onto Fe oxyhydroxide.

    PubMed

    Davranche, Mélanie; Pourret, Olivier; Gruau, Gérard; Dia, Aline

    2004-09-15

    Adsorption experiments of rare-earth elements (REE) onto hydrous ferric oxide (HFO) were performed to evaluate the impact of organic complexation on both REE(III) adsorption and the Ce(III) oxidation rate. Scavenging experiments were performed at pH 5.2 with NaCl and NaNO3 solutions containing either free REE (III) or REE(III)-humate complexes. The log K(d)(REE) patterns obtained from HFO suspensions exhibit a slight positive Ce anomaly and an M-type lanthanide tetrad effect, in contrast with the partitioning between REE(III)-humate complexes and HFO, which yields completely flat distribution patterns. The "organic" partitioning runs yield log K(d)(REEorganic)/log K(d)(DOC) ratios (DOC = dissolved organic carbon) close to 1.0, implying that the REE(III) and humate remain bound to each other during the adsorption experiment. The lack of any positive Ce anomaly or M-type lanthanide tetrad effect in the organic experiments seems to reflect an anionic adsorption of the REE-humate complex. Adsorption onto HFO takes place via the humate side of the REE(III)-humate complexes. The oxidation of Ce(III) by Fe(III) and the proportion of surface hydroxyl groups coordinated to REE(III) at the HFO surface are the two most commonly invoked processes for explaining the development of positive Ce anomalies and the M-type tetrad lanthanide effect. However, such processes cannot proceed since the REE are not in direct contact with the HFO suspensions, the latter being shielded by PHA. The present results further complicate the use of Ce anomalies as reliable paleoredox proxies in natural precipitates. They are also further demonstration that organic matter may inhibit the lanthanide tetrad effect in geological samples.

  15. Influence of phosphate on mobility and adsorption of REEs during weathering of granites in Thailand

    NASA Astrophysics Data System (ADS)

    Sanematsu, Kenzo; Kon, Yoshiaki; Imai, Akira

    2015-11-01

    The Permo-Jurassic North Thai (NT) Granites and the Late Cretaceous to Paleogene Western Province (WP) Granites in Thailand are contrasting in terms of tectonic settings and chemical compositions. The NT Granites, which are dominated by S-type features, are characterized by lower SiO2 contents and higher P2O5 contents than the WP Granites in this study. In order to compare the mobility and adsorption of rare earth elements (REEs) during weathering of the two granite suites, geochemical analyses were conducted on the granite and weathered granites. The weathered WP Granites show wider ranges of REEs + Y (REY) contents, percentages of ion-exchangeable REY and Ce anomalies than the weathered NT Granites. These results indicate that REEs were less mobile during weathering of the NT Granites than those of the WP Granites. The low mobility of REEs can be explained by the occurrences of residual monazite and secondary REE phosphates which immobilize REEs during weathering. Therefore, in the weathered NT Granites, REEs are mostly contained in the phosphate minerals. In contrast, the weathered WP Granites are dominated by ion-exchangeable REEs (adsorbed REEs) which are likely to exist on the surface of clays. Previous studies and our study results suggest that the ion-exchangeable REEs in the weathered granites were probably sourced from weatherable allanite, titanite, apatite and/or REE fluorocarbonate, and rarely from monazite and zircon, which are resistant to weathering. The weathered granites of low phosphate contents potentially show high percentages of ion-exchangeable REY, although they can be influenced by the degree of hydrothermal alteration or weathering of granites.

  16. REE Sorption Study of Seived -50 +100 Mesh Fraction of Media #1 in Brine #1 at Different Concentrations of REE at 70C

    SciTech Connect

    Gary Garland

    2015-06-29

    This dataset shows the sorption capacities of smaller grain size (-50 +100 mesh) of media #1 in brine #1 at different starting concentrations of REE's at elevated temperature of 70C. The experimental conditions are 2g of -50 +100 mesh media #1 to 150mL of REE solution at concentartions of .2ppm each, 2ppm each, and 20ppm each. The pH of the solution is 5.5, and the temperature was at 70C.

  17. High REE and Y concentrations in Co-Cu-Au ores of the Blackbird district, Idaho

    USGS Publications Warehouse

    Slack, J.F.

    2006-01-01

    Analysis of 11 samples of strata-bound Co-Cu-Au ore from the Blackbird district in Idaho shows previously unknown high concentrations of rare earth elements (REE) and Y, averaging 0.53 wt percent ???REE + Y oxides. Scanning electron microscopy indicates REE and Y residence in monazite, xenotime, and allanite that form complex intergrowths with cobaltite, suggesting coeval Co and REE + Y mineralization during the Mesoproterozoic. Occurrence of high REE and Y concentrations in the Blackbird ores, together with previously documented saline-rich fluid inclusions and Cl-rich biotite, suggest that these are not volcanogenic massive sulfide or sedimentary exhalative deposits but instead are iron oxide-copper-gold (IOCG) deposits. Other strata-bound Co deposits of Proterozoic age in the North American Cordillera and elsewhere in the world may have potential for REE and Y resources. IOCG deposits with abundant light REE should also be evaluated for possible unrecognized heavy REE and Y mineralization. ?? 2006 by Economic Geology.

  18. Experimental mineral/liquid partition coefficients of the rare earth elements /REE/, Sc and Sr for perovskite, spinel and melilite

    NASA Technical Reports Server (NTRS)

    Nagasawa, H.; Schreiber, H. D.; Morris, R. V.

    1980-01-01

    Experimental determinations of the mineral/liquid partition coefficients of REE (La, Sm, Eu, Gd, Tb, Yb and Lu), Sc and Sr are reported for the minerals perovskite, spinel and melilite in synthetic systems. Perovskite concentrates light REE with respect to the residual liquid but shows no preference for heavy REE. Spinel greatly discriminates against the incorporation of REE, especially light REE, into its crystal structure. The partition of REE into melilite from a silicate liquid is quite dependent upon both the bulk melt and melilite solid-solution (gehlenite and akermanite components) compositions. As such, melilite can be enriched in REE or will reject REE with corresponding strong negative or strong positive Eu anomalies, respectively.

  19. Some Remarks on the Interpretation of the REE-in-two-Mineral Thermobarometers

    NASA Astrophysics Data System (ADS)

    Sun, C.; Liang, Y.; Yao, L.; Dygert, N. J.; Wang, C.

    2015-12-01

    Distributions of REE between mantle minerals depend on temperature, pressure and mineral compositions, and can be used as thermobarometers. We have developed a REE-in-two-pyroxene thermometer, a REE-in-garnet-clinopyroxene thermobarometer, and a REE-in-plagioclase-augite thermometer for ultramafic and mafic rocks. These trace element based two-mineral thermobarometers are built on parameterized lattice strain models for mineral-melt REE partitioning that we independently calibrated using published data from mineral-melt partitioning experiments. The physical meanings of calculated temperatures and pressures can be understood in terms of the average closure temperatures and closure pressures of REE in cooling bi-mineralic systems. Because trivalent REE diffuse slower than divalent Ca-Fe-Mg in minerals, the REE-based thermobarometers may record early thermal event(s), whereas the major element based thermometers may record more recent thermal events in closed systems that experienced cooling. A number of geological and geodynamic processes can result in decreases in temperature and possibly pressure over time: mantle upwelling beneath mid-ocean ridge spreading centers or in response to lower crust delamination, exhumation, heat loss to country rock from crustal magma chambers. For shallow level intrusive or extrusive mafic rocks, temperatures derived from the REE-in-plagioclase-augite thermometer may correspond to plagioclase saturation temperature. Hence application of REE- and Ca-Fe-Mg based thermobarometers to the same samples can shed new insight into the thermal history of mafic and ultramafic rocks. Initial applications of the REE-in-two-mineral thermobarometers to Earth and planetary samples have lead to a number of interesting observations which we will summarize in this presentation. However, care and caution must be exercised when processing and interpreting data from REE-in-two-mineral thermobarometers. Common issues include inaccuracies in REE data

  20. Heterogeneous rare earth element (REE) patterns and concentrations in a fossil bone: Implications for the use of REE in vertebrate taphonomy and fossilization history

    NASA Astrophysics Data System (ADS)

    Suarez, Celina A.; Macpherson, G. L.; González, Luis A.; Grandstaff, David E.

    2010-05-01

    A bone fragment (CGDQ-3) of Falcariusutahensis, a therizinosaur from the Early Cretaceous Cedar Mountain Formation, Utah, contained within a carbonate nodule, was analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) in order to investigate REE variability within a thin-walled phalanx. Previous studies have found depth-related REE pattern variations; however, in CGDQ-3 variation occurs along the circumference of the bone. NASC-normalized REE patterns and concentrations vary between two apparent end members. A light-REE enriched (LREE) pattern, similar to solution ICP-MS analysis of this bone, characterizes approximately two-thirds of the bone fragment. Total REE concentrations are high and do not vary significantly from the periosteal surface to the medullar surface. Conversely, the remaining one-third of the bone has REE patterns that are MREE-depleted and low in total REE concentrations. REE concentrations in this part of the bone do not vary significantly from the periosteal to the medullar surface. A positive Ce anomaly is found throughout the entire bone, and is greatest within the LREE-enriched portion of the bone. This, in combination with the LREE-enrichment, suggests that the bone fossilized under reducing conditions. The distance between the LREE-enriched and MREE-depleted regions is less than 1 mm. Isotopic and petrographic analyses of the bone and surrounding carbonate matrix suggest the REE patterns in the bone were the result of partial fossilization/incomplete filling of micro-pore spaces around bone crystallites in an environment with changing redox conditions. The lower, MREE-depleted part of the bone fossilized contemporaneously with a pendant cement that formed on the underside of the bone in the vadose zone. Formation of the pendant cement restricted water flow through the bone, isolating the lower portion, which incorporated a MREE-depleted pattern. The upper part of the bone (LREE-enriched side) fossilized under

  1. Re+e- and an effective QCD charge

    NASA Astrophysics Data System (ADS)

    Gomez, J. D.; Natale, A. A.

    2016-01-01

    We consider the electron-positron annihilation process into hadrons Re+e- up to O (αs3), and we adopt the smearing method suggest by Poggio, Quinn, and Weinberg to confront the experimental data with theory. As a theoretical model, we use a QCD coupling constant frozen in the low-energy regime, where this coupling can be parametrized in terms of an effective dynamical gluon mass (mg) which is determined through Schwinger-Dyson equations. In order to find the best fit between experimental data and theory, we perform a χ2 study, that, within the uncertainties of the approach, has a minimum value when mg/ΛQCD is in the range 1.2-1.4. These values are in agreement with other phenomenological determinations of this ratio and lead to an infrared effective charge αs(0 )≈0.7 . We comment how this effective charge may affect the global duality mass scale that indicates the frontier between perturbative and nonperturbative physics.

  2. Duality and genetic significance of REE speciation in tourmaline from tin deposits of the Far East

    NASA Astrophysics Data System (ADS)

    Gorelikova, N. V.; Balashov, F. V.; Bychkova, Ya. V.; Minervina, E. A.; Korostelev, P. G.; Magazina, O. L.; Bortnikov, N. S.

    2016-04-01

    The distribution of REEs and some minor elements in tourmalines of different associations and deposits of the Russian Far East is studied by the methods of ICP-MS, ICP-MS with laser ablation and scanning electron microscopy. The duality of REE speciation in tourmaline is established: in high-temperature varieties, most REEs (mainly HREEs) are incorporated in rare minerals (monazite, xenotime, zircon, and F-Ce-Y carbonate), whereas hydrothermal ores are characterized by isomorphic incorporation of LREEs in the mineral structure, as well as by a fine admixture of zircon at the expense of detrital clasts in flyschoid rocks with the zones of tourmalinization.

  3. Three MSFC Directors; Dr. Petrone, Dr. Rees, and Dr. von Braun

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Three Marshall Space Flight Center (MSFC) Directors: at left, Dr. Rocco A. Petrone (1973-1974), who had been named to succeed Dr. Rees, then-present director (Center); Dr. Eberhard Rees (1970-1973); and past director (right), Dr. Wernher von Braun (1960-1970). This photo was taken at the Redstone Arsenal Officers Club where over three hundred people had gathered to honor the career of Dr. Rees which sparned more than thirty years in rocketry and space exploration and wish him well upon his pending retirement on January 26, 1973.

  4. Origin of REE mineralization in the Bastnäs-type Fe-REE-(Cu-Mo-Bi-Au) deposits, Bergslagen, Sweden

    NASA Astrophysics Data System (ADS)

    Holtstam, Dan; Andersson, Ulf B.; Broman, Curt; Mansfeld, Joakim

    2014-12-01

    The Bastnäs-type deposits, with mineral assemblages of Fe oxides, Ca-Mg silicates, rare earth element (REE) silicates, REE fluorocarbonates, and Cu-Fe-Mo-Bi sulfides, are associated with marble horizons in a strongly Na, K, and/or Mg altered, metavolcanic succession, over a distance of at least 80 km in a SW-NE trending zone in western Bergslagen. Two subtypes occur: (1) enriched (relative to the other type) in light REE (LREE) and Fe, exemplified by the Bastnäs and Rödbergsgruvan deposits, and (2) enriched in heavy REE (HREE), Y, Mg, Ca, and F, represented by deposits in the Norberg district. Bastnäsite hosts primary fluid H2O-CO2 inclusions with salinities of 6-29 eq. wt% CaCl2 and with total homogenization temperatures ( Th tot) of ca. 300-400 °C. Subtype 2 has late-stage fluorite with fluid inclusions that show 1-16 eq. wt% NaCl and Th tot of ca. 90-150 °C. Molybdenite Re-Os ages obtained from three deposits are 1,904 ± 6, 1,863 ± 4, and 1,842 ± 4 Ma. Nd isotopic data from five different REE minerals yielded no defined isochron, but a range in ɛNd (1.88 Ga) of +0.2 to +1.6. The oxygen isotope values (δ18OSMOW) of dolomite and calcite from the associated REE-mineralized skarn and recrystallized carbonate assemblages lie in the range 6.1-8.6 ‰, overlapping with those of the host marbles. Carbon isotope values (δ13CPDB) show typical magmatic signatures of -6.7 to -4.4 ‰, while the host marbles group around ca. -2.4 ‰. The sulfur isotope (δ34SCDT) values of associated sulfides range between -10.8 and +0.2 ‰. The combined evidence suggests REE mineralization, beginning at 1.9 Ga, from mainly Svecofennian, juvenile magmatic (>400 °C) fluids carrying Si, F, Cl, S, CO2, and the REE in addition to other metals; mineralization occurred through reactions with dolomitic layers in the supracrustal units coevally with regional metasomatic alteration associated with fluid circulation through an extensive active volcano-plutonic complex.

  5. Cancer vaccines: looking to the future. Interview by Jenaid Rees.

    PubMed

    Apostolopoulos, Vasso

    2013-10-01

    Interview by Jenaid Rees (Commissioning Editor) Vasso Apostolopoulos has been working in the field of cancer vaccines since 1991, and human clinical trials on her work have been conducted since 1994. Her work has been at the forefront of scientific research into the development of a vaccine for cancer and she has received over 90 awards and honours in recognition of her achievements. Some notable awards include, the Premier's Award for medical research, was named Young Australian of the Year (Victoria), recipient of the Channel 10/Herald Sun Young Achiever of the Year Award as well as being awarded the Order of Brigadier General of the Phoenix Battalion by the Greek President. In 1998 Apostolopoulos received the NHMRC CJ Martin Research Fellowship and worked at the Scripps Research Institute in California, USA, for 3.5 years and returned to the Austin Research Institute (VIC, Australia), and headed the Immunology and Vaccine Laboratory receiving the NHMRC RD Wright Fellowship. Upon her return to Australia, Apostolopoulos received the Victorian Tall Poppy Award, the Bodossaki Foundation Academic Prize, was inducted into the Victorian Honour roll of Women, was a torchbearer for the Melbourne leg of the International Athens 2004 Olympic Torch Relay, was named Woman of the Year, and is an Australia Day Ambassador. Her contribution into cancer research, vaccines and immunology has been extensive - publishing over 200 scientific papers and books, an inventor on 14 patents and collaborates with over 50 national and international Research Institutes and Universities. Her current research interests are in the development of new improved cancer vaccines and new modes of antigen delivery for immune stimulation. She is also interested in chronic diseases treatment and prevention through immunotherapy. She serves on the Editorial Board for Expert Review of Vaccines.

  6. Mineral recorders of pegmatite internal evolution: REE contents of tourmaline from the Bob Ingersoll pegmatite, South Dakota

    SciTech Connect

    Jolliff, B.L.; Papike, J.J.

    1987-08-01

    Trace rare earth elements (REE) have been determined by radiochemical neutron activation analysis for tourmaline samples from an internally zoned, rare-element, granitic pegmatite, located in the Black Hills, South Dakota. The Total REE concentrations range from 40 ppm-0.2 ppm, and are highest in tourmaline from the exomorphic halo (country rock) and pegmatite border zone. Chondrite-normalized patterns are highly fractionated from light REE to heavy REE; and REE concentrations decrease in tourmaline from the outer wall zone and first intermediate zone, through the inner wall zone and third intermediate zone, to lowest levels in the pegmatite core. The REEs, as recorded by tourmaline, appear to behave compatibly in this pegmatite system due to early crystallization of apatite and other possible REE-sink minerals. The large range of REE concentrations and differences in slopes of chondrite-normalized patterns probably also reflect significant changes in the structural state of the pegmatite melt, caused by changes in pH/sub 2/O and other volatiles (B, F, P) as crystallization progressed. Tourmaline samples that appear to have been fluid-derived are HREE-depleted relative to coexisting silicate-melt-derived tourmaline. Tourmaline does not exhibit any strong preference for specific REEs, rather its REE content appears to reflect the REE content of the medium from which the tourmaline crystallized.

  7. Characterization and migration of atmospheric REE in soils and surface waters

    NASA Astrophysics Data System (ADS)

    Aubert, Dominique; Stille, Peter; Probst, Anne; Gauthier-lafaye, François; Pourcelot, Laurent; Del nero, Mireille

    2002-10-01

    Rainwater and snow collected from three different sites in France (Vosges Mountains, French Alps and Strasbourg) show more or less similar shapes of their REE distribution patterns. Rainwater from Strasbourg is the most REE enriched sample, whereas precipitations from the two mountainous, less polluted catchments are less REE enriched and have concentrations close to seawater. They are all strongly LREE depleted. Different water samples from an Alpine watershed comprising snow, interstitial, puddle and streamwater show similar REE distributions with LREE enrichment (rainwater normalized) but MREE and HREE depletion. In this environment, where water transfer from the soil to the river is very quick due to the low thickness of the soils, it appears that REE in streamwater mainly originate from atmospheric inputs. Different is the behaviour of the REE in the spring- and streamwaters from the Vosges Mountains. These waters of long residence time in the deep soil horizons react with soil and bedrock REE carrying minerals and show especially significant negative Eu anomalies compared to atmospheric inputs. Their Sr and Nd isotopic data suggest that most of the Sr and Nd originate from apatite leaching or dissolution. Soil solutions and soil leachates from the upper soil horizons due to alteration processes strongly depleted in REE carrying minerals, have REE distribution patterns close to those of lichens and throughfall. Throughfall is slightly more enriched especially in light REE than filtered rainwater probably due to leaching of atmospheric particles deposited on the foliage and also to leaf excretion. Data suggest that Sr and Nd isotopes of the soil solutions in the upper soil horizons originate from two different sources: 1) An atmospheric source with fertilizer, dust and seawater components and 2) A source mainly determined by mineral dissolution in the soil. These two different sources are also recognizable in the Sr and Nd isotopic composition of the tree

  8. Chemical characteristic of R chondrites in the light of P, REEs, Th and U abundances

    NASA Astrophysics Data System (ADS)

    Khan, Rahat; Shirai, Naoki; Ebihara, Mitsuru

    2015-07-01

    Rare earth elements (REEs), Th, U and P were determined in 15 Rumuruti (R)-type chondrites and the Allende CV chondrite. Repeated analyses of Allende for REEs, Th and U by ICP-MS and P by ICP-AES, and comparisons of these data with literature values ensure high reproducibility (precision) and reliability (accuracy) of acquired data. CI-normalized REE abundances in R chondrites are slightly enriched in heavy REEs with a small, positive Ce anomaly, in contrast to Allende. CI-normalized Pr/Tm and Nd/Yb ratios show a positive correlation, suggesting the heterogeneous mixing of two components (CI-like and refractory-rich materials) during the accretion of the R chondrite parent body. A Ce anomaly, however, was likely homogeneously present in the nebula. A mean Th/U ratio of R chondrites is 3.81 ± 0.13 (1 σ), which is 5.1% higher than the CI ratio. Probably, the Th-U fractionation was inherited from the nebula from which the R chondrite parent body formed. Besides the Th-U fractionation, REEs and Th-U are heterogeneously fractionated in R chondrites, for which parent body processing is assumed to be the cause. A mean P content of R chondrites (1254 μg/g) is higher than for any ordinary chondrite and is close to the EL mean. There appears to be a negative correlation between P and REEs contents in R chondrites. It is probable that REEs were diluted by extraneously supplied, REEs-depleted and P-containing materials (schreibersite or metal). This process must have occurred heterogeneously during accretion so that the heterogeneity of P-containing materials was preserved in the R chondrite parent body and individual R chondrites.

  9. In situ ion microprobe U-Pb dating and REE abundances of a carboniferous conodont

    NASA Astrophysics Data System (ADS)

    Sano, Yuji; Terada, Kentaro

    We report here in situ ion microprobe U-Pb dating of a conodont micro-fossil using an ion microprobe method. Thirteen spots on the single fragment of the Carboniferous conodont (size: approximately 800 µm × 100 µm) yield a 238U/206Pb isochron age of 323±36 Ma and a Tera-Wasserburg concordia intercept age of 332±44 Ma in a three-dimensional 238U/206Pb-207Pb/206 Pb-204Pb/206Pb diagram. These ages are consistent with the depositional and early diagenetic ages of the fossil in its host Mississippian sedimentary sequence within experimental error. The success of the method depends on the chemical fractionation of U from Pb within a hundred-µm length scale and the consequent variations in Pb isotopic compositions due to radioactive decay. Shale-normalized rare earth element (REE) abundances of two spots on the same sample show flat patterns from light REE to middle REE and decreases from middle REE to heavy REE with negative anomalies of both Ce and Eu. The REE characteristics are significantly different from those of Devonian conodonts reported by other workers, suggesting discrepant redox states and/or formation environments.

  10. Rare earth elements (REEs) in the tropical South Atlantic and quantitative deconvolution of their non-conservative behavior

    NASA Astrophysics Data System (ADS)

    Zheng, Xin-Yuan; Plancherel, Yves; Saito, Mak A.; Scott, Peter M.; Henderson, Gideon M.

    2016-03-01

    This study presents new concentration measurements of dissolved rare earth elements (dREEs) along a full-depth east-west section across the tropical South Atlantic (∼12°S), and uses these data to investigate the oceanic cycling of the REEs. Enrichment of dREEs, associated with the redox cycling of Fe-Mn oxides, is observed in the oxygen minimum zone (OMZ) off the African shelf. For deeper-waters, a multi-parameter mixing model was developed to deconvolve the relative importance of physical transport (i.e., water mass mixing) from biogeochemical controls on the dREE distribution in the deep Atlantic. This approach enables chemical processes involved in REE cycling, not apparent from the measurements alone, to be distinguished and quantified. Results show that the measured dREE concentrations below ∼1000 m are dominantly controlled (>75%) by preformed REE concentrations resulting from water mass mixing. This result indicates that the linear correlation between dREEs and dissolved Si observed in Atlantic deep waters results from the dominantly conservative behavior of these tracers, rather than from similar chemical processes influencing both dREEs and Si. Minor addition of dREEs (∼10% of dNd and ∼5% of dYb) is observed in the deep (>∼4000 m) Brazil Basin, resulting from either remineralization of particles in-situ or along the flow path. Greater addition of dREEs (up to 25% for dNd and 20% for dYb) is found at ∼1500 m and below ∼4000 m in the Angola Basin near the African continental margin. Cerium anomalies suggest that different sources are responsible for these dREE addition plumes. The 1500 m excess is most likely attributed to dREE release from Fe oxides, whereas the 4000 m excess may be due to remineralization of calcite. Higher particulate fluxes and a more sluggish ocean circulation in the Angola Basin may explain why the dREE excesses in this basin are significantly higher than that observed in the Brazil Basin. Hydrothermal venting over the

  11. Ion-adsorption REEs in regolith of the Liberty Hill pluton, South Carolina, USA: An effect of hydrothermal alteration

    USGS Publications Warehouse

    Bern, Carleton R.; Yesavage, Tiffany; Foley, Nora K.

    2017-01-01

    Ion-adsorbed rare earth element (REE) deposits supply the majority of world heavy REE production and substantial light REE production, but relatively little is known of their occurrence outside Southeast Asia. We examined the distribution and forms of REEs on a North American pluton located in the highly weathered and slowly eroding South Carolina Piedmont. The Hercynian Liberty Hill pluton experiences a modern climate that includes ~ 1500 mm annual rainfall and a mean annual temperature of 17 °C. The pluton is medium- to coarse-grained biotite-amphibole granite with minor biotite granite facies. REE-bearing phases are diverse and include monazite, zircon, titanite, allanite, apatite and bastnäsite. Weathered profiles were sampled up to 7 m-deep across the ~ 400 km2 pluton. In one profile, ion-adsorbed REEs plus yttrium (REE + Y) ranged up to 581 mg/kg and accounted for up to 77% of total REE + Y in saprolite. In other profiles, ion-adsorbed REE + Y ranged 12–194 mg/kg and only accounted for 3–37% of totals. The profile most enriched in ion-adsorbed REEs was located along the mapped boundary of two granite facies and contained trioctahedral smectite in the saprolite, evidence suggestive of hydrothermal alteration of biotite at that location. Post-emplacement deuteric alteration can generate easily weathered REE phases, particularly fluorocarbonates. In the case of Liberty Hill, hydrothermal alteration may have converted less soluble to more soluble REE minerals. Additionally, regolith P content was inversely correlated with the fraction ion-adsorbed REEs, and weathering related secondary REE-phosphates were found in some regolith profiles. Both patterns illustrate how low P content aids in the accumulation of ion-adsorbed REEs. The localized occurrence at Liberty Hill sheds light on conditions and processes that generate ion-adsorbed REEs.

  12. REE mineralization in the carbonatites of the sung valley ultramafic-alkaline-carbonatite complex, Meghalaya, India

    NASA Astrophysics Data System (ADS)

    Sadiq, Mohd.; Ranjith, A.; Umrao, Ravi

    2014-12-01

    The Early Cretaceous Sung Valley Ultramafic-Alkaline-Carbonatite (SUAC) complex intruded the Proterozoic Shillong Group of rocks and located in the East Khasi Hills and West Jaintia Hills districts of Meghalaya. The SUAC complex is a bowl-shaped depression covering an area of about 26 km2 and is comprised serpentinised peridotite forming the core of the complex with pyroxenite rim. Alkaline rocks are dominantly ijolite and nepheline syenite, occur as ring-shaped bodies as well as dykes. Carbonatites are, the youngest intrusive phase in the complex, where they form oval-shaped bodies, small dykes and veins. During the course of large scale mapping in parts of the Sung Valley complex, eleven carbonatite bodies were delineated. These isolated carbonatite bodies have a general NW-SE and E-W trend and vary from 20-125 m long and 10-40 m wide. Calcite carbonatite is the dominant variety and comprises minor dolomite and apatite and accessory olivine, magnetite, pyrochlore and phlogopite. The REE-bearing minerals identified in the Sung Valley carbonatites are bastnäsite-(Ce), ancylite-(Ce), belovite-(Ce), britholite-(Ce) and pyrochlore that are associated with calcite and apatite. The presence of REE carbonates and phosphates associated with REE-Nb bearing pyrochlore enhances the economic potential of the Sung Valley carbonatites. Trace-element geochemistry also reveals an enrichment of LREEs in the carbonatites and average ΣREE value of 0.102% in 26 bed rock samples. Channel samples shows average ΣREE values of 0.103 wt%. Moreover, few samples from carbonatite bodies has indicated relatively higher values for Sn, Hf, Ta and U. Since the present study focuses surface evaluation of REE, therefore, detailed subsurface exploration will be of immense help to determine the REE and other associated mineralization of the Sung Valley carbonatite prospect.

  13. Temporal variations in the export of REE in boreal catchments of varying character and size

    NASA Astrophysics Data System (ADS)

    Köhler, S.; Lidman, F.; Mörth, M.; Björkvald, L.; Laudon, H.

    2009-04-01

    Organic matter and iron colloids have a large impact on the mobilisation of trivalent elements such as aluminium (Al), rare earth elements (REE) and actinides. Recent results of the relative importance of these colloids are diverging though (POURRET et al., 2007); STEINMANN and STILLE, 2008) and there is a general lack of information of the importance of flow pathways and landscape type on the relative importance of the various colloidal fractions that mobilizes REE from the catchment soils. In this study we present the data of water chemical analysis of a series of catchments with varying size and character but all within the boreal zone. Two speciation techniques and two column separation methods involving ion exchange were used to quantify the causes for the temporal variation of the dissolved amounts of trivalent ions in these water courses. Our study indicates that REE export is controlled mostly by landscape type while changes in the acid-base character of organic matter are of minor importance. Changes in flow pathways in a riparian zone in one of the studied areas in a forested site may be used to decipher the effect of chemical versus physical processes for the mobilisation of REE and aluminium and open up the possibility for a quantitative modelling of the varying sources of REE. Iron and aluminium are mobilized together with organic matter in varying amounts in different landscape types and this affects the REE export from the various landscape elements. While the amount of strongly bound aluminium mobilized from the catchments usually correlate positively with any of the REE this is not the case for strongly bound iron. Fractionation patterns of REE are discussed and the observed binding of REE to organic matter was modelled using the speciation program WHAM VI (TIPPING, 1998). Pourret O., Davranche M., Gruau G., and Dia A. (2007) Organic complexation of rare earth elements in natural waters: Evaluating model calculations from ultrafiltration data

  14. Some Nd and Sr isotopic systematics for the REE-enriched deposit at Bayan Obo, China

    USGS Publications Warehouse

    Philpotts, J.; Tatsumoto, M.; Li, X.; Wang, K.

    1991-01-01

    Sm/1bNd and Rb/1bSr isotopic systematics have been determined for rare-earth element (REE) rich samples of carbonate, iron ore, and silicate types from the world's largest known REE deposit at Bayan Obo, China. The results yielded neither Rb/1bSr nor Sm/1bNd isochrons within analytical error. Isochronous relationships may have been disturbed in part by younger events. Modes in isotopic composition suggest two Sr reservoirs; the low 87Sr 86Sr ratios of 0.703 and 0.704 measured for two carbonates may be of mantle origin. The Sm/1bNd data delineate a trend at ??? 1 Ga; this trend might represent a disturbed fractionation event or mixing of Nd reservoirs. The REE ores could not have formed in a single fractionation event during the igneous activity at 260 Ma. Model ages suggest that the ore REE were isolated from mantle sources between ??? 1.7 and ??? 1.3 Ga. This time period hosts major anorogenic igneous activity, including anorthosites, and a number of other unusual REE iron ores. ?? 1991.

  15. Thermodynamic modeling of REE behavior in oxidized hydrothermal fluids of high sulfate sulfur concentrations

    NASA Astrophysics Data System (ADS)

    Shironosova, G. P.; Kolonin, G. R.; Borovikov, A. A.; Borisenko, A. S.

    2016-08-01

    Thermodynamic calculations using the HCh software were made for mineral equilibriums including REEs in the fluoride-sulfide-chloride-carbonate-sulfate-system in the presence of Na, Ca, and P with fluids of various acidities-alkalinities [11]. The obtained thermodynamic characteristics of thenardite allowed us to carry out the calculations for this phase under complicated hydrothermal conditions simulating the presence of oxidized fluids at 500-100°C and 2000-125 bar. Among other solid phases, REEs-fluorite, monazite, and REE-F-apatite were formed as CaF2-(Ln,Y)F3, LnPO4, and Ca5(PO4)3F-(Ln,Y)3(PO4)3 ideal solid solutions, respectively, where Ln is La, Ce, Pr, Nd, Sm, Eu, and Gd. Xenotime, anhydrite, elemental sulfur, and calcite were found as well.

  16. Penicillium expansum Link strain for a biometallurgical method to recover REEs from WEEE.

    PubMed

    Di Piazza, Simone; Cecchi, Grazia; Cardinale, Anna Maria; Carbone, Cristina; Mariotti, Mauro Giorgio; Giovine, Marco; Zotti, Mirca

    2017-02-01

    Due to the wide range of applications in high-tech solutions, Rare Earth Elements (REEs) have become object of great interest. In the last years several studies regarding technologies for REE extraction from secondary resources have been carried out. In particular biotechnologies, which use tolerant and accumulator microorganisms to recover and recycle precious metals, are replacing traditional methods. This paper describes an original biometallurgical method to recover REEs from waste electrical and electronic equipment (WEEE) by using a strain of Penicillium expansum Link isolated from an ecotoxic metal contaminated site. The resulting product is a high concentrated solution of Lanthanum (up to 390ppm) and Terbium (up to 1520ppm) obtained from WEEE. Under this perspective, the proposed protocol can be considered a method of recycling exploiting biometallurgy. Finally, the process is the subject of the Italian patent application n. 102015000041404 submitted by the University of Genoa.

  17. REE chemistry of MORB and OIB explained by microchemical disequilibrium melting models

    NASA Astrophysics Data System (ADS)

    Grose, C. J.; Afonso, J. C.

    2015-12-01

    We have developed a two-dimensional numerical model of multi-phase coarsening, diffusive trace element partitioning, and near-fractional melting. The model is applied to decompression melting of MORB and OIB sources and the prediction of REE (La, Sm, and Yb) in erupted lavas. We show that the major features in global OIB REE systematics are easily explained via the so-called LID effect. The properties of models which do explain the data indicate that the OIB source cannot be hot (>1400°C) and may be compositionally similar to the MORB source. Moreover, our models predict that the thermo-mechanical LAB temperature is about 1225°C, average grain radii in the OIB source is on the order of 2-5 mm, and the bulk source compositions of REE are about 2-7 times higher than previous estimates.

  18. Rare earth elements (REEs): effects on germination and growth of selected crop and native plant species.

    PubMed

    Thomas, Philippe J; Carpenter, David; Boutin, Céline; Allison, Jane E

    2014-02-01

    The phytotoxicity of rare earth elements (REEs) is still poorly understood. The exposure-response relationships of three native Canadian plant species (common milkweed, Asclepias syriaca L., showy ticktrefoil, Desmodium canadense (L.) DC. and switchgrass, Panicum virgatum L.) and two commonly used crop species (radish, Raphanus sativus L., and tomato, Solanum lycopersicum L.) to the REEs lanthanum (La), yttrium (Y) and cerium (Ce) were tested. In separate experiments, seven to eight doses of each element were added to the soil prior to sowing seeds. Effects of REE dose on germination were established through measures of total percent germination and speed of germination; effects on growth were established through determination of above ground biomass. Ce was also tested at two pH levels and plant tissue analysis was conducted on pooled samples. Effects on germination were mostly observed with Ce at low pH. However, effects on growth were more pronounced, with detectable inhibition concentrations causing 10% and 25% reductions in biomass for the two native forb species (A. syriaca and D. canadense) with all REEs and on all species tested with Ce in both soil pH treatments. Concentration of Ce in aboveground biomass was lower than root Ce content, and followed the dose-response trend. From values measured in natural soils around the world, our results continue to support the notion that REEs are of limited toxicity and not considered extremely hazardous to the environment. However, in areas where REE contamination is likely, the slow accumulation of these elements in the environment could become problematic.

  19. Mobilization and redistribution of REEs and thorium in a syenitic lateritic profile: A mass balance study

    SciTech Connect

    Braun, J.J.; Pagel, M.; Herbillon ); Rosin, C. )

    1993-09-01

    REE-Th geochemistry and mineralogy have been studied in a lateritic profile derived from a syenite at Akongo in SW Cameroon. REE and Th mass balance calculations for the host-rock minerals show that at least 70% of the LREEs and 50% of the HREEs are contained in allanite, apatite, titanite, and epidote and at least 50% of the Th is controlled by the same accessory materials which represent about 2 wt% of the unaltered syenite. These accessory phases are destroyed during the first stages of weathering causing most of the REEs and Th to be rapidly released into the soil. Comparison of the variation in the Zr, Ti, and Th content as a function of the apparent density of the different zones of the saprolite shows that Th is the least mobile element. The presence of secondary thorianite (ThO[sub 2]), the etched surface on zircon grains, and the presence of Ti in secondary cerianite support this geochemical interpretation. The concentration of thorium was, therefore, chosen as invariant relative to the concentration of the other elements, especially the REEs, in mass balance calculations. Most of the REEs are leached in the iron-rich upper horizons (loose nodular horizon, iron crust, and top of mottled clay horizon). Where the groundwater table moves (saprolite and bottom of the mottled clay horizon), the REEs are fractionated and redistributed. There is a juxtaposition of leached and accumulation zones with precipitation of LREE aluminous hydrated phosphates. This study supports the existence of two different cycles for the redistribution of elements in the soil: (1) as dissolved ions in the saprolite horizon, and (2) as individual particles in the upper part of the profile.

  20. Ion microprobe U-Pb dating and REE abundance of biogenic apatite

    NASA Astrophysics Data System (ADS)

    Sano, Y.; Terada, K.; Ueki, S.

    2001-12-01

    If the direct U-Pb dating of a fossil itself is possible, the method could have great impact on stratigraphic studies in establishing the absolute chronology of sedimentary sequences. Micro fossil ?conodont? are candidates for this purpose since they consist of apatite (Ca2(PO5)3 (F,Cl,OH)), which would uptake U, Th and Pb after sedimentation no longer than a few million years and is supposed to remain closed to U and Pb under relatively low effective closure temperature. We report here results of direct ion microprobe U-Th-Pb dating of two conodonts; Trichognathus from Kinderhookian stage of Mississippian sedimentary sequence from Illinois Basin region in North America and Panderodus from a Llandoverian sedimentary sequence on Langkawi Island, northern Malaysia. Secondary purpose of the study is to indicate in situ analysis of all REE on the same spots of U-Pb measurements. Samples were cast into epoxy resin discs with a few grains of standard apatite, PRAP, derived from an alkaline rock of Prairie Lake circular complex in the Canadian Shield and polished until they were exposed through their mid-sections. U, Th and REE abundances, and Pb isotopic compositions were measured by using SHRIMP installed at Hiroshima University. Thirteen spots on Trichognathus yield a 238U/206Pb isochron age of 323+/-36 Ma, which is consistent with the depositional and early diagenetic ages. Fifteen spots on Panderodus give 232Th/208Pb isochron age of 429+/-50 Ma, which is again comparable to an early Silurian. Shale-normalized REE of Trichognathus shows a broadly flat pattern from light to middle REE and a decrease from middle to heavy REE with negative anomalies of Ce and Eu. In contrast Panderodus indicates a concave-shape pattern with middle REE enrichment. These characteristics are probably due to a different formation environment as suggested by other workers.

  1. Hydrothermal REE and Zr Ore Forming Processes in Peralkaline Granitic Systems

    NASA Astrophysics Data System (ADS)

    Gysi, A. P.

    2015-12-01

    Anorogenic peralkaline igneous systems display extreme enrichment of REE and Zr with a hydrothermal overprint leading to post-magmatic metal mobilization. Strange Lake in Canada, for example, is a mid-Proterozoic peralkaline granitic intrusion and host to a world-class REE-Zr deposit with >50 Mt ore (>1.5 wt.% REE and >3 wt.% Zr). In contrast to porphyry systems, peralkaline systems are poorly understood and hydrothermal metal mobilization models are only in the early stage of their development. This is partly due to the paucity of thermodynamic data for REE-bearing minerals and aqueous species, and the complexity of the hydrothermal fluids (enrichment of F, P and Cl), which make it difficult to develop thermodynamic models of metal partitioning. This study aims to show the link between alteration stages and metal mobilization using Strange Lake as a natural laboratory and combine these observations with numerical modeling. Four types of alteration were recognized at Strange Lake: i) alkali (i.e. K and Na) metasomatism related to interaction with NaCl-bearing orthomagmatic fluids, ii) acidic alteration by HCl-HF-bearing fluids originating from the pegmatites followed by iii) aegirinization of the border of the pegmatites and surrounding granites and by iv) pervasive Ca-F-metasomatism. The acidic alteration accounts for most of the hydrothermal metal mobilization in and outward from the pegmatites, whereas the Ca-F-metasomatism led to metal deposition and resulted from interaction of an acidic F-rich fluid with a Ca-bearing fluid. Numerical simulations of fluid-rock reactions with saline HCl-HF-bearing fluids at 400 °C to 250 °C indicate that temperature, availability of F/Cl and pH limit the mobility of Zr and REE. Fluids with pH <2 led to the formation of quartz and fluorite in the core of the pegmatites and to an increase in the stability of REE chloride species favorable for REE mobilization. The mobilization of Zr was favored at low temperature with the

  2. Use of arsenic and REE in black shales as potential environmental tracers in hydraulic fracturing operations

    NASA Astrophysics Data System (ADS)

    Yang, J.; Torres, M. E.; Haley, B. A.; McKay, J. L.; Algeo, T. J.; Hakala, A.; Joseph, C.; Edenborn, H. M.

    2013-12-01

    Black shales commonly targeted for shale gas development were deposited under low oxygen concentrations, and typically contain high As levels. The depositional environment governs its solid-phase association in the sediment, which in turn will influence degree of remobilization during hydraulic fracturing. Organic carbon (OC), trace element (TE) and REE distributions have been used as tracers for assessing deep water redox conditions at the time of deposition in the Midcontinent Sea of North America (Algeo and Heckel, 2008), during large-scale oceanic anoxic events (e.g., Bunte, 2009) and in modern OC-rich sediments underlying coastal upwelling areas (e.g., Brumsack, 2006). We will present REE and As data from a collection of six different locations in the continental US (Kansas, Iowa, Oklahoma, Kentucky, North Dakota and Pennsylvania), ranging in age from Devonian to Upper Pennsylvanian, and from a Cretaceous black shale drilled on the Demerara Rise during ODP Leg 207. We interpret our data in light of the depositional framework previously developed for these locations based on OC and TE patterns, to document the mechanisms leading to REE and As accumulation, and explore their potential use as environmental proxies and their diagenetic remobilization during burial, as part of our future goal to develop a predictive evaluation of arsenic release from shales and transport with flowback waters. Total REE abundance (ΣREE) ranged from 35 to 420 ppm in an organic rich sample from Stark shale, KS. PAAS-normalized REE concentrations ranged from 0.5 to 7, with the highest enrichments observed in the MREE (Sm to Ho). Neither the ΣREE nor the MREE enrichments correlated with OC concentrations or postulated depositional redox conditions, suggesting a principal association with aluminosilicates and selective REE fractionation during diagenesis. In the anoxic reducing environments in which black shales were deposited, sulfide minerals such as FeS2 trap aqueous arsenic in the

  3. Petrogenesis, Geochemistry and REE Mineralization of the Ilmenite-series Granitoids in Northern Palawan, Philippines

    NASA Astrophysics Data System (ADS)

    Padrones, J. T.; Imai, A.; Takahashi, R.; Gabo, J. A. S.; Tani, K.

    2015-12-01

    A sliver of the Palawan Continental Block associated with the Late Yanshanian magmatism was recently recognized in northern Palawan, Philippines. This intrusive unit is the Late Cretaceous Daroctan granites. This granitic intrusive body, as well as the Middle Miocene Kapoas granitoids, were studied for their petrogenesis. The REE mineralization was also examined because of the I-type and ilmenite-series character of the granitoids and the close spatial and temporal relationship with the granitic units in southern and eastern China, which are viable sources for ion-adsorption type REE mineralization. The granitic intrusive rocks being investigated in this study are composed of biotite granodiorite and biotite granites. Both intrusive units are characterized by high-K calc-alkaline, intermediate I and S-types, and peraluminous. Despite the difference in ages, the geochemistry of both intrusive units shows distinct similarities which suggest same source materials, the partial melting of middle to lower continental crust. The granitoids in the Kapoas show higher light rare earth element (LREE) enrichment than that in the Daroctan but the weathered granitic crusts show higher enrichment in the Daroctan granites compared to the parent granitic rocks. Sequential leaching extraction for REE, Y, and Nb using 8 reagents which selectively dissolved REEs with different mode of occurence (i.e. water soluble, ion-exchangeable salts, Pb- displaceable, acid soluble, Mn-oxide occluded, organically-bound, amorphous Fe-oxide occluded, and crystalline Fe-oxide occluded) show that the Daroctan granites has a potential of ion-adsorption type REE resource with 60 - 73% adsorbed ΣREE. On the other hand, about 18 - 28% adsorbed ΣREE was extracted in the Kapoas granitoid samples. Only monazite occurs as the residual REE-bearing mineral in the Kapoas granitoids, while monazite and xenotime occur in the Daroctan granite. In both samples, mica minerals were altered to vermiculite, which

  4. The assessment of REE patterns and 143Nd/ 144Nd ratios in fish remains

    NASA Astrophysics Data System (ADS)

    Grandjean, Patricia; Cappetta, Henri; Michard, Annie; Albarède, Francis

    1987-07-01

    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, ɛ 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 (ɛ Nd ≈ -13.5), the Miocene Persian Gulf (ɛ Nd = -3.1), and Bolivia during the Late Cretaceous (ɛ 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 andɛ Nd data suggests that the assignment of Jurassic-Cretaceous samples measured so far to open-sea water masses is still ambiguous.

  5. Mineral chemistry of Rare Earth Element (REE) mineralization, Browns Ranges, Western Australia

    NASA Astrophysics Data System (ADS)

    Cook, Nigel J.; Ciobanu, Cristiana L.; O'Rielly, Daniel; Wilson, Robin; Das, Kevin; Wade, Benjamin

    2013-07-01

    ‘Green energy futures’ are driving unprecedented demand for Rare Earth Elements (REE), underpinning significant exploration activity worldwide. Understanding how economic REE concentrations form is critical for development of exploration models. REE mineralisation in the Browns Ranges, Gordon Downs Region, Western Australia, comprises xenotime-dominant mineralisation hosted within Archaean to Palaeoproterozoic metasedimentary units (Browns Range Metamorphics). Mineralogical, petrographic and mineral-chemical investigation, including trace element analysis by Laser-Ablation Inductively-Coupled Plasma Mass Spectroscopy, gives insights into the mineralogical distribution and partitioning of REE, and also provides evidence for the genetic evolution of the Browns Range REE mineralisation via a succession of hydrothermal processes. Two main REE-bearing minerals are identified: xenotime [(Y,REE)PO4], which is HREE selective; and subordinate florencite [(REEAl3(PO4)2(OH)6] which is LREE selective. Two morphological generations of xenotime are recognised; compositions are however consistent. Xenotime contains Dy (up to 6.5 wt.%), Er (up to 4.35 wt.%), Gd (up to 7.56 wt.%), Yb (up to 4.65 wt.%) and Y (up to 43.3 wt.%). Laser Ablation ICP-MS element mapping revealed a subtle compositional zoning in some xenotime grains. LREE appear concentrated in the grain cores or closest to the initial point of growth whereas HREE, particularly Tm, Yb and Lu, are highest at the outer margins of the grains. The HREE enrichment at the outer margins is mimicked by As, Sc, V, Sr, U, Th and radiogenic Pb. Florencite is commonly zoned and contains Ce (up to 11.54 wt.%), Nd (up to 10.05 wt.%) and La (up to 5.40 wt.%) and is also notably enriched in Sr (up to 11.63 wt.%) and Ca. Zircon (which is not a significant contributor of REEs overall due to its low abundance in the rocks) is also enriched in REE (up to 13 wt.% ΣREE) and is the principal host of Sc (up to 0.8 wt.%). Early, coarse

  6. REE partitioning between apatite and melt in a peralkaline volcanic suite, Kenya Rift Valley

    USGS Publications Warehouse

    Macdonald, R.; Baginski, B.; Belkin, H.E.; Dzierzanowski, P.; Jezak, L.

    2009-01-01

    Electron microprobe analyses are presented for fluorapatite phenocrysts from a benmoreite-peralkaline rhyolite volcanic suite from the Kenya Rift Valley. The rocks have previously been well characterized petrographically and their crystallization conditions are reasonably well known. The REE contents in the M site increase towards the rhyolites, with a maximum britholite component of ~35 mol.%. Chondrite-normalized REE patterns are rather flat between La and Sm and then decrease towards Yb. Sodium and Fe occupy up to 1% and 4%, respectively, of the M site. The major coupled substitution is REE3+ + Si4+ ??? Ca2+ + P5+. The substitution REE3+ + Na+ ??? 2Ca2+ has been of minor importance. The relatively large Fe contents were perhaps facilitated by the low fo2 conditions of crystallization. Zoning is ubiquitous and resulted from both fractional crystallization and magma mixing. Apatites in some rhyolites are relatively Y-depleted, perhaps reflecting crystallization from melts which had precipitated zircon. Mineral/glass (melt) ratios for two rhyolites are unusually high, with maxima at Sm (762, 1123). ?? 2008 The Mineralogical Society.

  7. TPE/REE separation with the use of zirconium salt of HDBP

    NASA Astrophysics Data System (ADS)

    Glekov, R. G.; Shmidt, O. V.; Palenik, Yu. V.; Goletsky, N. D.; Sukhareva, S. Yu.; Fedorov, Yu. S.; Zilberman, B. Ya.

    2003-01-01

    Partitioning of long-lived radionuclides (minor actinides, fission products) is considered as TBP-compatible ZEALEX-process for extraction separation of transplutonium elements (TPE) and rare-earth elements (REE), as well as Y, Mo, Fe and residual amounts of Np, Pu, U. Zirconium salt of dibutyl phosphoric acid (ZS-HDBP) dissolved in 30 % TBP is used as a solvent. The process was tested in multistage centrifugal contactors. Lanthanides, Y and TPE, as well as Mo, Fe were extracted from high-level Purex raffinate, Am and ceric subgroup of REE being separated from the polyvalent elements by stripping with HNO3. TPE/REE partitioning was achieved in the second cycle of the ZEALEX-process using DTPA in formic acid media. The integral decontamination factor of Am from La and Ce after both cycles is >200, from Pr and Nd 20-30 and from Sm and Eu 3.6; REE strips in both cycles contained <0,1% of the initial amount of TPE.

  8. Application of REE geochemical signatures for Mesozoic sediment provenance to the Gettysburg Basin, Pennsylvania

    NASA Astrophysics Data System (ADS)

    Blake, Johanna M.; Peters, Stephen C.; Johannesson, Karen H.

    2017-03-01

    Rift basins adjacent to accreted terranes provide accommodation space for sediments eroded from these terranes. Despite similar depositional environments and geologic age, rocks of the Triassic Gettysburg Basin have approximately half the arsenic concentrations of the adjacent Newark Basin. Quartz-feldspar-lithics (QFL) diagrams and rare earth element (REE) geochemical signatures can inform sediment provenance. Here we investigate REE geochemical signatures of the sedimentary rocks in the Triassic Gettysburg rift basin, with the goal of distinguishing the main sources of siliciclastic sediment among the Appalachian foreland in the rift footwall from Piedmont arc and Iapetan continental margin rocks exposed in the hanging wall and ultimately understanding the geochemical cycling of arsenic to the Gettysburg Basin. Shale-normalized REE spider diagrams and Mann-Whitney tests on trace element ratios suggest that the Gettysburg Basin samples show patterns that most closely resemble those of the Iapetus Continental Slope Rise Iapetus Rift Volcanic, and Accretionary Complex deposits. Mann-Whitney Rank Sum analysis suggest that the Iapetus Continental Slope Rise terrane is the main source of sediments to the basin, which confirms results from prior QFL analysis and shows the utility of REE fingerprinting in provenance analysis. The main sources of sediment have smaller minimum and maximum arsenic concentrations than other terranes and the Newark Basin sediments, additionally suggesting the source of arsenic to the Gettysburg Basin is based upon specific terranes.

  9. Optical spectra and luminescence of REE and TRU for analytical purposes in chloride melts

    SciTech Connect

    Aloy, A.S.; Gorshkov, N.G.; Nekhoroshkov, S.N.; Osipenko, A.G.; Mayorshin, A.A.

    2013-07-01

    This paper analyzes absorption spectra of molten salts containing some of the actinide and rare-earth elements (REE) and evaluated the prospects of using the individual transitions to control the composition of the spent molten salts using adsorption and luminescence spectroscopy from the standpoint of the theory of Judd-Ofelt. It is shown that the fluorescent method can be recommended only for the monitoring of the degree of purification of the molten salt from the REE in the final stage, when only trace amounts of fission products are in the molten salt. In this case, the content of REE in the molten process is much smaller than that of the used model samples and that eliminates the problem of a significant decrease in the population levels of fluorescent Eu{sup 3+} by quenching impurities. In addition, the presence of salt in the matrix of americium and curium can cause self-luminescence of Eu{sup 3+} due to alpha disintegration energy of transuranics, which also complicates the quantitative measurement of luminescence for the determination of REE.

  10. Volatility Fractionation of REE and Other Trace Elements During Vacuum Evaporation

    NASA Astrophysics Data System (ADS)

    Davis, A. M.; Hashimoto, A.

    1995-09-01

    Volatility-fractionated REE patterns were first recognized in calcium-, aluminum-rich inclusions (CAIs) in meteorites over 20 years ago [1]. Such REE patterns can be modeled quite well by equilibrium thermodynamic calculations [2,3,4], but kinetic effects on fractionation of trace elements between gas and solids or liquids have remained less well-known. We have previously reported on experiments in which melts of initial REE-doped chondritic composition [5] and perovskite composition [6] were evaporated in vacuo. In both series of experiments, residues were formed that had large negative Ce anomalies and small negative Pr and Eu anomalies, but no other significant REE fractionations were observed. In an effort to produce more extensive fractionation of REE and other refractory elements, we made a new, more refractory, starting material (stoichiometric CaTiO3 doped with a number of refractory trace elements in chondritic proportions to a total "trace" element level of 5 wt%) and evaporated it under vacuum at a higher temperature (2150 degrees C) than the earlier experiments (1800-2000 degrees C). The results are shown in Fig. 1. Despite the high temperature, the two most extreme evaporation residues reached the solidus during evaporation; the other residues with lower degrees of evaporation remained liquid until cooled at the end of the experiment. The most extreme residue consists largely of mixed Sc, Y and Zr oxides; most of the Ti and nearly all of the Ca have evaporated. In this residue, there are large depletions in Sr, Nb, Ba, Ce and Eu and smaller depletions of La, Pr, Nd, Sm and Yb compared to Sc, Zr and most heavy REE. There is, however, little fractionation of the heavy REE from one another. The chemical composition and even the physical state of the residues change with degree of evaporation, undoubtedly affecting evaporation rates of trace elements. For example, even though the experiments are all carried out at a single temperature and both Ce and Eu

  11. Major, trace and REE geochemistry of recent sediments from lower Catumbela River (Angola)

    NASA Astrophysics Data System (ADS)

    Vinha, Manuela; Silva, M. G.; Cabral Pinto, Marina M. S.; Carvalho, Paula Cristina S.

    2016-03-01

    The mineralogy, texture, major, trace and rare earth elements, from recent sediment samples collected in the lower Catumbela River, were analysed in this study to characterize and discuss the factors controlling its geochemistry and provide data that can be used as tracers of Catumbela River inputs to the Angolan continental shelf. The sediments are mainly sands and silty-sands, but sandy-silt also occurs and the mineralogy is composed of quartz, feldspar, phyllosilicates, magnetite, ilmenite and also carbonates when the river crosses limestones and marls in the downstream sector. The hydraulic sorting originates magnetite-ilmenite and REE-enriched minerals placers. The mineralogy of the sediments is controlled by the source rocks and the degree of chemical weathering is lower than erosion. The texture is mainly controlled by location. There is enrichment in all the analysed trace elements in the fine grained, clay minerals and Fe-oxy-hydroxides rich sediments, compared to the coarse grained and quartz plus feldspar rich ones. The coarse grained sediments (without the placers) are impoverished in ΣREE when compared with UCC and NASC compositions, while the fine grained sediments have ΣREE contents similar to UCC and NASC. The placers have ΣREE contents up to 959.59 mg/kg. The source composition is the dominant factor controlling the REE geochemistry of the analysed sediments as there is no difference in the (La/Yb)N, (La/Sm)N and (Gd/Yb)N ratios in coarse and fine grained sediments. The sorting of magnetite, ilmenite, zircon, throrite, thorianite, rutile and titanite explain the HREE/LREE enriched patterns of the coarse grained sediments.

  12. Neodymium isotopic study of rare earth element sources and mobility in hydrothermal Fe oxide (Fe-P-REE) systems

    SciTech Connect

    Gleason, J.D.; Marikos, M.A.; Barton, M.D.; Johnson, D.A.

    2000-03-01

    Rare earth element (REE)-enriched, igneous-related hydrothermal Fe-oxide hosted (Fe-P-REE) systems from four areas in North America have been analyzed for their neodymium iosotopic composition to constrain REE sources and mobility in these systems. The Nd isotopic results evidence a common pattern of REE concentration from igneous sources despite large differences in age (Proterozoic to Tertiary), tectonic setting (subduction vs. intraplate), and magmatic style (mafic vs. felsic). In the Middle Proterozoic St. Francois Mountains terrane of southeastern Missouri, {epsilon}{sub Nd} for Fe-P-REE (apatite, monazite, xenotime) deposits ranges from +3.5 to +5.1, similar to associated felsic to intermediate igneous rocks of the same age ({epsilon}{sub Nd} = +2.6 to +6.2). At the mid-Jurassic Humboldt mafic complex in western Nevada, {epsilon}{sub Nd} for Fe-P-REE (apatite) mineralization varies between +1.1 and +2.4, similar to associated mafic igneous rocks ({minus}1.0 to +3.5). In the nearby Cortez Mountains in central Nevada, mid-Jurassic felsic volcanic and plutonic rocks ({epsilon}{sub Nd} = {minus}2.0 to {minus}4.4) are associated with Fe-P-REE (apatite-monazite) mineralization having similar {epsilon}{sub Nd}({minus}1.7 to {minus}2.4). At Cerro de Mercado, Durango, Mexico, all assemblages analyzed in this Tertiary rhyolite-hosted Fe oxide deposit have identical isotopic compositions with {epsilon}{sub Nd} = {minus}2.5. These data are consistent with coeval igneous host rocks being the primary source of REE in all four regions, and are inconsistent with a significant contribution of REE from other sources. Interpretations of the origin of these hydrothermal systems and their concomitant REE mobility must account for nonspecialized igneous sources and varied tectonic settings.

  13. Microbially mediated formation of a new REE enriched Mn-oxide, Ytterby mine, Sweden

    NASA Astrophysics Data System (ADS)

    Sjöberg, Susanne; Allard, Bert; Rattray, Jayne E.; Callac, Nolwenn; Skelton, Alasdair; Ivarsson, Magnus; Karlsson, Stefan; Sjöberg, Viktor; Dupraz, Christophe

    2016-04-01

    Characterization of a black substance seeping from fractured bedrock in a subterranean tunnel revealed a new, microbially mediated, secondary manganese oxide mineralisation, highly enriched in rare earth elements (REEs). This tunnel is dry and at shallow depth and was built to convert the former Ytterby mine, known for the discovery of yttrium (Y), scandium (Sc) and five rare earth elements, into a fuel deposit for the Swedish Armed Forces. As the type locality of these rare earth elements, the Ytterby mine gave its name to yttrium, ytterbium, erbium and terbium. Geochemical analysis shows that the substance is enriched in REEs with concentrations one to two orders of magnitude higher than the surrounding rocks. Elemental analysis and X-ray diffraction establish that the main component is a manganese oxide of the birnessite type (general formula: [Na,Ca]0.5[Mn(III),Mn(IV)]2O4xAq). There are also minor fractions of calcite, some other manganese oxides, feldspars, quartz and about 1% organic matter, but no iron oxides. Leaching studies (sequential and selective) were performed in order to establish how the minor components are associated with the matrix (in the lattice or merely adsorbed on the outer surface). It shows that the Ytterby birnessite contains about 1% REEs in the lattice, as well as calcium but no sodium. Formation of birnessite by manganese oxidizing bacteria is well-known (e.g. Tebo et al, 2004). Quantitative PCR shows that the total number of bacteria in the Ytterby substance is in the order 1010 cells per g substance while the water feeding the fracture has in the order of 106 cells per ml groundwater. qPCR data further confirm that manganese oxidizing microorganisms are present and that the abundance varies with the seasons. Analysis of the precipitated manganese using electron paramagnetic resonance spectroscopy shows that the substance is composed of two or more components, with one part having a biogenic signature. The occurrence of C31 to C35

  14. REE Mineralization in Kiruna-type Magnetite-Apatite Ore Deposits: Magmatism and Metasomatism

    NASA Astrophysics Data System (ADS)

    Harlov, D. E.

    2015-12-01

    Magnetite-apatite ore bodies of the Kiruna type occur worldwide and are generally associated with volcanic rocks or volcanism. They also show strong evidence of extensive metasomatism over a wide P-T range. Notable examples include the Kiirunavaara ore body, northern Sweden (Harlov et al., 2002, Chem. Geol., 191, 47-72); the Grängesberg ore body, central Sweden (Jonsson et al., 2010, NGF abstracts, vol 1, 88-89); the Mineville ore body, Adirondacks, New York, USA (McKeown and Klemc, 1956, U.S. Geol Sur Bull (1956), pp. 9-23); the Pea Ridge ore body, SE Missouri, USA (Kerr, 1998, MS Thesis, Univ. Windsor, Windsor, Ontario, Canada 113 pp); the Jurassic Marcona ore body in south-central Peru (Chen et al., 2010, Econ Geol, 105, 1441-1456); and a collection of ore bodies from the Bafq Region, central Iran (Daliran et al., 2010, Geol. Assoc. Canada, Short Course Notes, v. 20, p.147-159). In these ore bodies, low Th and U monazite, xenotime, allanite, REE carbonates, and/or REE fluorides are commonly associated with the apatite as inclusions, rim grains, or as independent grains in the surrounding mineral matrix. High contrast BSE imaging, coupled with EMPA and LA-ICPMS, indicates that the apatite has experienced fluid-induced alteration in the form of (Y+REE) + Na + Si + Cl depletion implying that it served as the source for the (Y+REE) (e.g. Kiirunavaara, northern Sweden; Harlov et al., 2002). Formation of monazite and xenotime associated with fluorapatite, as inclusions or rim grains, has experimentally been demonstrated to originate from the fluorapatite as the result of fluid-aided, coupled dissolution-reprecipitation processes (Harlov et al., 2005, Contrib. Mineral. Petrol. 150, 268-286). This is explains the low Th and U content of the monazite and xenotime. Fluid sources could range from 700-900 °C, residual, acidic (HCl, H2HSO4) grain boundary fluids, remaining after the last stages of ore body crystallization, to later stage, cooler (< 600 °C) (H2O-CO2-(Na

  15. Trace element and REE composition of five samples of the Yucca Mountain calcite-silica deposits. Special report No. 8

    SciTech Connect

    Livingston, D.

    1993-07-01

    The attached materials document the results of part of a recent effort of geochemical sampling and analysis at Yucca Mountain and nearby regions. The efforts come as a result of interest in comprehensive analyses of rare earth elements (REE), lanthanum (La) through lutecium (Lu). Several additional, non-REE analyses were obtained as well. Commercially available REE analyses have proved to be insufficiently sensitive for geochemical purposes. Dr. Roman Schmitt at the Radiation Center at Oregon State University in Corvallis was sent five samples as a trial effort. The results are very encouraging. The purpose of compiling Dr. Schmitt`s report and the other materials is to inform the sponsor of his independent observations of these results and other information that sent to him. To provide a more complete appreciation of the utility of REE analyses a copy of Dave Vaniman`s recent article is included in which he notes that REE analyses from Yucca Mountain indicate the occurrence of two distinctly different REE patterns as do several other chemical parameters of the calcite-silica deposits. Our four samples with high equivalent CaCO{sub 3} were collected from sites we believe to be spring deposits. One sample, 24D, is from southern Crater Flat which is acknowledged by U.S.G.S. investigators to be a spring deposit. All four of these samples have REE patterns similar to those from the saturated zone reported by Vaniman.

  16. High contents of rare earth elements (REEs) in stream waters of a Cu-Pb-Zn mining area.

    PubMed

    Protano, G; Riccobono, F

    2002-01-01

    Stream waters draining an old mining area present very high rare earth element (REE) contents, reaching 928 microg/l as the maximum total value (sigmaREE). The middle rare earth elements (MREEs) are usually enriched with respect to both the light (LREEs) and heavy (HREEs) elements of this group, producing a characteristic "roof-shaped" pattern of the shale Post-Archean Australian Shales-normalized concentrations. At the Fenice Capanne Mine (FCM), the most important base metal mine of the study area, the REE source coincides with the mine tailings, mostly the oldest ones composed of iron-rich materials. The geochemical history of the REEs released into Noni stream from wastes in the FCM area is strictly determined by the pH, which controls the REE speciation and in-stream processes. The formation of Al-rich and mainly Fe-rich flocs effectively scavenges the REEs, which are readily and drastically removed from the solution when the pH approaches neutrality. Leaching experiments performed on flocs and waste materials demonstrate that Fe-oxides/oxyhydroxides play a key role in the release of lanthanide elements into stream waters. The origin of the "roof-shaped" REE distribution pattern as well as the peculiar geochemical behavior of some lanthanide elements in the aqueous system are discussed.

  17. Uptake and Effects of Six Rare Earth Elements (REEs) on Selected Native and Crop Species Growing in Contaminated Soils

    PubMed Central

    Carpenter, David; Boutin, Céline; Allison, Jane E.; Parsons, Jessica L.; Ellis, Deanna M.

    2015-01-01

    Rare earth elements (REEs) have become increasingly important metals used in modern technology. Processes including mining, oil refining, discarding of obsolete equipment containing REEs, and the use of REE-containing phosphate fertilizers may increase the likelihood of environmental contamination. However, there is a scarcity of information on the toxicity and accumulation of these metals to terrestrial primary producers in contaminated soils. The objective of this work was to assess the phytotoxicity and uptake from contaminated soil of six REEs (chloride forms of praseodymium, neodymium, samarium, terbium, dysprosium, and erbium) on three native plants (Asclepias syriaca L., Desmodium canadense (L.) DC., Panicum virgatum L.) and two crop species (Raphanus sativus L., Solanum lycopersicum L.) in separate dose-response experiments under growth chamber conditions. Limited effects of REEs were found on seed germination and speed of germination. Effects on aboveground and belowground biomass were more pronounced, especially for the three native species, which were always more sensitive than the crop species tested. Inhibition concentrations (IC25 and IC50) causing 25 or 50% reductions in plant biomass respectively, were measured. For the native species, the majority of aboveground biomass IC25s (11 out of 18) fell within 100 to 300 mg REE/kg dry soil. In comparison to the native species, IC25s for the crops were always greater than 400 mg REE/kg, with the majority of results (seven out of 12) falling above 700 mg REE/kg. IC50s were often not detected for the crops. Root biomass of native species was also affected at lower doses than in crops. REE uptake by plants was higher in the belowground parts than in the above-ground plant tissues. Results also revealed that chloride may have contributed to the sensitivity of the native species, Desmodium canadense, one of the most sensitive species studied. Nevertheless, these results demonstrated that phytotoxicity may be a

  18. Cause of large negative Eu anomaly in the highly evolved A-type granites with REE tetrad pattern

    NASA Astrophysics Data System (ADS)

    Lee, S.; Asahara, Y.; Tanaka, T.; Lee, M.; Lee, S. R.

    2013-12-01

    REE tetrad pattern with strongly large negative Eu anomaly is one of the specific geochemical phenomena observed in the highly evolved, fractionated granite or A-type granite. The large negative Eu anomaly from the highly evolved or fractionated granites related with REE tetrad effect was discussed in a lot of literatures (e.g. [1] Muecke and Clarke, 1981; [2] Irber, 1999; [3] Jahn et al., 2001). Recently, Lee et al.[4] also suggested that Eu anomalies and REE tetrad pattern from the highly fractionated A-type Muamsa and Weolaksan granites in the Okcheon Metamorphic Belt, Korea, might be associated with a fractionation between the residual melt and a coexisting aqueous high temperature fluid. Their origin and geochemical significance are ongoing yet. In order to clarify cause of large negative Eu anomaly in the granite with REE tetrad effect more clearly, we reanalyzed REE abundance of the Muamsa and Weolaksan granites using MC-ICP-MS at the origins laboratory of the University of Chicago. We also measured REE abundances of the constituent minerals using quadruple ICP-MS at the Korea Polar Research Institute. In this report, we show the re-analyzed REE data from the whole rock as well as new REE data from constituent minerals of the granite with REE tetrad effect. Then, we discuss the cause of large negative Eu anomaly in the highly evolved granite with REE tetrad effect. Especially, the granites with very large negative Eu anomaly also show large negative Ce anomaly. Lee et al. [4] mentioned that negative Ce anomalies were formed after granite emplacement. However, our new data indicate that negative Ce anomaly might be formed during the same geochemical process with very large negative Eu anomaly. This suggests that the REE tetrad effect may be related with a change of oxidation state during a magma evolution. Therefore, we will discuss REE tetrad effect, negative Eu and Ce anomaly as an indicator for the change of oxidation state of magma during the emplacement

  19. Partition coefficients of Hf, Zr, and REE between zircon, apatite, and liquid

    USGS Publications Warehouse

    Fujimaki, H.

    1986-01-01

    Concentration ratios of Hf, Zr, and REE between zircon, apatite, and liquid were determined for three igneous compositions: two andesites and a diorite. The concentration ratios of these elements between zircon and corresponding liquid can approximate the partition coefficient. Although the concentration ratios between apatite and andesite groundmass can be considered as partition coefficients, those for the apatite in the diorite may deviate from the partition coefficients. The HREE partition coefficients between zircon and liquid are very large (100 for Er to 500 for Lu), and the Hf partition coefficient is even larger. The REE partition coefficients between apatite and liquid are convex upward, and large (D=10-100), whereas the Hf and Zr partition coefficients are less than 1. The large differences between partition coefficients of Lu and Hf for zircon-liquid and for apatite-liquid are confirmed. These partition coefficients are useful for petrogenetic models involving zircon and apatite. ?? 1986 Springer-Verlag.

  20. Neutron Activation Analysis of the Rare Earth Elements (REE) - With Emphasis on Geological Materials

    NASA Astrophysics Data System (ADS)

    Stosch, Heinz-Günter

    2016-08-01

    Neutron activation analysis (NAA) has been the analytical method of choice for rare earth element (REE) analysis from the early 1960s through the 1980s. At that time, irradiation facilitieswere widely available and fairly easily accessible. The development of high-resolution gamma-ray detectors in the mid-1960s eliminated, formany applications, the need for chemical separation of the REE from the matrix material, making NAA a reliable and effective analytical tool. While not as precise as isotopedilution mass spectrometry, NAA was competitive by being sensitive for the analysis of about half of the rare earths (La, Ce, Nd, Sm, Eu, Tb, Yb, Lu). The development of inductively coupled plasma mass spectrometry since the 1980s, together with decommissioning of research reactors and the lack of installation of new ones in Europe and North America has led to the rapid decline of NAA.

  1. Pomozdino - An anomalous, high-MgO/FeO, yet REE-rich eucrite

    NASA Technical Reports Server (NTRS)

    Warren, P. H.; Jerde, E. A.; Migdisova, L. F.; Iaroshevskii, A. A.

    1990-01-01

    A new chemical analysis and petrographic data for the Pomozdino basaltic achondrite are presented. Earlier indications that Pomozdino is a eucrite and that it is a monomict breccia with an anomalous, REE-rich, yet high-MgO/FeO bulk composition, are confirmed. Characteristics such as texture, composition, and REE concentration are examined and compared to those in other publications. A model for the origin of this meteorite, as a partial cumulate with an uncommonly high content of trapped liquid, is found to be preferable. Two alternatives of the origin are suggested, one of which implies that the parent melt is roughly similar in composition to Stannern. The other considers Pomozdino as a possible primary partial melt, derived from a source region far more magnesian than generally envisaged for the sources of primary eucritic partial melts. It is concluded that at least some Stannern-like eucrites were involved in fractional crystallization, and thus do not represent primary partial melts.

  2. Dr. von Braun with Gen. Ostrander, Dr. Rees, and Gen. Barclay

    NASA Technical Reports Server (NTRS)

    1959-01-01

    In this 1959 photo, taken at Cape Canaveral, Florida, Dr. von Braun (2nd from left) Director of the U.S. Army Ballistic Missile Agency's (ABMA) Development Operations Division, is shown conferring with Air Force Major General Donald R. Ostrander (left), on assignment at NASA as launch vehicle director; Dr. Eberhard Rees, deputy to Dr. von Braun, and Army Brigadier General John Barclay, commander of the ABMA.

  3. Cathodoluminescence emission of REE (Dy, Pr and Eu) doped LaAlO3 phosphors

    NASA Astrophysics Data System (ADS)

    Boronat, C.; Rivera, T.; Garcia-Guinea, J.; Correcher, V.

    2017-01-01

    Luminescence emission from rare earth (REE) ions doped materials are being of interest since can be employed as scintillators, catalysts, battery and magnetic materials, etc. We herein report on the preliminary results obtained from the cathodoluminescence (CL) properties of undoped LaAlO3 (LAO) and LaAlO3: REE3+ (REE=Dy3+, Pr3+ and Eu3+) samples synthesized by a sol-gel process based on the Pechini's method with a spray-drying technique. The samples, previously characterized by means of Environmental Scanning Electron Microscopy and Energy Dispersive X-Ray Analysis Spectrometry, display CL spectra with well-defined peaks that could specifically be associated with the LAO structure (in the range of 300-450 nm) and point defects (from 450 to 800 nm) spectral regions. The observed wavebands are as follows: (i) 480 and 570 from the Dy-doped LAO correspond respectively to 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions, (ii) 490-638 from the Pr-doped LAO is linked to 3P0→3H4, 1D2→3H4 transitions and (iii) 590 and 620 where the dopant Eu3+ gives rise to 5D0→7F1 and 5D0→7F2 transitions and (iv) a UV-blue broad band is associated with NBHOC in undoped LAO. Such emissions are due to the presence of the 4f electrons of rare earth ions that are shielded by the outer 5s and 5p electrons, the intra-4f emission spectra of REE that induce sharp and narrow wavebands.

  4. REE and Sr, Nd, Pb isotopic geochemistry of Huangyishan basalt, Kuandian, Liaoning, Northeast China

    USGS Publications Warehouse

    Xie, G.-h.; Wang, J.-w.; Wei, K.-j.; Liu, C.-q.; Tatsumoto, M.; Basn, A.R.

    1990-01-01

    In the light of major element geochemistry, mineral chemistry and REE and isotopic data, the small but apparent isotopic differences between the Cenozoic volcanic rocks east and west of the Tancheng-Lujiang fault are believed to be caused by the mixing and metasomatism of crustal and mantle material in the mantle source region in response to Pacific plate subduction. The presence of phlogopite and pargasite in mantle xenoliths lends strong support to mantle metasomatism. ?? 1990.

  5. Rearrangement of REE's in Austin Glen Fm. (Ord. ), Ulster Co. , NY

    SciTech Connect

    Bock, B.; McLennan, S.M.; Hanson, G.N. . Dept. of ESS)

    1993-03-01

    Austin Glen turbidites are part of the allochthonous Taconic sequence of the Appalachian foreland basin. Graywackes in the sequence are rich in quartz, sedimentary rock fragments and carbonate, but have little feldspar. The abundant matrix makes it difficult to recognize volcanic components. REE patterns and Nd isotopes were analyzed to distinguish the relative abundance of volcanic versus older crustal components. REE patterns for shales and graywackes in a hundred-meter section are characterized by variable LREE-enrichment. An inclined array was expected on the f[sub Sm/Md] [minus] [var epsilon][sub Nd] diagram resulting from mixed sources. The vertical array shows that the samples had the same Nd-isotopic composition at 470 Ma. The restricted [var epsilon][sub Nd] of 8.0 [plus minus] 0.4 indicates the provenance was dominated by older crustal components that likely had similar Sm/Nd. The large variation in f[sub Sm/Nd] requires rearrangement of the REEs during sedimentary processes or early diagenesis at about 470 Ma.

  6. Parameterized Lattice Strain Models for REE Partitioning between Amphibole and Silicate Melt

    NASA Astrophysics Data System (ADS)

    Shimizu, K.; Liang, Y.; Sun, C.; Jackson, C.; Saal, A. E.

    2015-12-01

    The distribution of REE between amphibole and silicate melt is important for understanding a variety of igneous processes involving amphibole. In general, amphibole-melt REE partition coefficients (DREE) depend on pressure (P), temperature (T), and compositions of amphibole and melt. A previous study parameterized the DREE in amphibole-melt solely as a function of melt composition [1]. Here, we use published REE partitioning data between amphibole and basaltic melt, the lattice strain model [2], and non-linear least squares regression method to parameterize key partitioning parameters in the lattice strain model (D0, r0, and E) as a function of P, T, and both amphibole and melt compositions. We focus on experimental data obtained by LA-ICP-MS and ion probe, and experiments close to equilibrium. Amphiboles and coexisting melts from the 38 experiments that we compiled span a wide range of compositions with the Mg# of amphibole and melt ranging from 36 to 100 and 15 to 99, respectively. Two models, which give nearly identical results, are explored in this study. In the first model, D0 is a function of T and amphibole composition: it negatively correlates with T and MgM1,2,3 content in amphibole, and positively correlates with TiM1,2,3 content in amphibole. In the second model, D0 is solely a function of the melt composition: it negatively correlates with the mole fraction of Ca in the melt. Interestingly, r0 and E are both constant and identical between the two models, suggesting D0 in the two models are equivalent. The latter allows us to develop a new thermometer for amphibole-melt equilibria. As an independent test, we compared model-derived temperatures with those reported in the phase equilibrium experiments. The predicted temperatures are within ±41°C on average of the reported temperatures, adding confidence to our parameterizations of D0. Our two parameterized lattice strain models can be used to model REE fractionation between amphibole and basaltic melts

  7. Tetrad effects in REE abundance patterns of chondrules from CM meteorites: Implications for aqueous alteration on the CM parent asteroid

    NASA Astrophysics Data System (ADS)

    Inoue, Mutsuo; Nakamura, Noboru; Kimura, Makoto

    2009-09-01

    Lanthanide tetrad effect in bulk chondrules from two moderately altered CM chondrites, Murchison and Yamato-793321 (Y-793321), are reported for the first time. Twenty-three chondrules were petrographically characterized and analyzed for 10 rare earth elements (REE) and other trace and major elements (Ba, Sr, Rb, K, Ca, Mg and Fe) using the precise isotope dilution technique. The results indicate systematic depletion (several times) of alkali and alkaline earths compared to CV and CO chondrules. Most of the porphyritic olivine (8 PO) and olivine-pyroxene (4 POP), porphyritic and radial pyroxene (2 PP, 1 RP), and granular olivine (1 GO) chondrules show a light-REE (L-REE) depleted, heavy-REE (H-REE) smoothly fractionated pattern composed of four (upward convex) segments possessing a relatively large negative Eu anomaly (CI-normalized La/Sm, Lu/Er and Eu/Eu* ratios = 0.3-1: Eu*, normal value). On the other hand, all barred-olivine (5 BO) chondrules, a few PO and POP indicate almost a flat L-REE pattern. In addition, regardless of their textural types, nearly half of the chondrules have a variable degree of Ce and Yb anomalies, and/or L/H-REE discontinuity, which is similar to CV and CO chondrules. The observed L- and H-convex REE patterns accompanied with the negative Eu anomaly is the first known case for chondrules as well as meteoritic materials, but have been previously reported for geological samples such as sedimentary rocks, late stage igneous and metamorphic rocks, and are explained as the lanthanide tetrad effect, which plausibly results from fluid-rock interaction. We suggest that the marked REE fractionations occurred by the selective incorporation of L-, H-REEs and Eu into alteration products in the matrix during alteration processes on the CM parent body, but that the gas/solid REE fractionation characteristics established in the nebula have basically remained unchanged. We suggest that the tetrad effects observed here represent a new index of physico

  8. Assessing anthropogenic levels, speciation, and potential mobility of rare earth elements (REEs) in ex-tin mining area.

    PubMed

    Khan, Aysha Masood; Yusoff, Ismail; Bakar, Nor Kartini Abu; Bakar, Ahmad Farid Abu; Alias, Yatimah

    2016-12-01

    A study was carried out to determine the level of rare earth elements (REEs) in water and sediment samples from ex-mining lakes and River in Kinta Valley, Perak, Malaysia. Surface water and sediments from an ex-mining lake and Kinta River water samples were analyzed for REEs by inductively coupled plasma mass spectrometry. The total concentration of REEs in the ex-mining lake water samples and sediments were found to be 3685 mg/l and 14159 mg/kg, respectively, while the total concentration of REEs in Kinta River water sample was found to be 1224 mg/l. REEs in mining lake water were found to be within 2.42 mg/l (Tb) to 46.50 mg/l (Ce), while for the Kinta River, it was 1.33 mg/l (Ho) to 29.95 mg/l (Ce). Sediment samples were also found with REEs from 9.81 mg/kg (Ho) to 765.84 mg/kg (Ce). Ce showed the highest average concentrations for mining lake (3.88 to 49.08 mg/l) and Kinta River (4.44 to 33.15 mg/l) water samples, while the concentration of La was the highest (11.59 to 771.61 mg/kg) in the mining lake sediment. Lu was shown to have the highest enrichment of REEs in ex-mining lake sediments (107.3). Multivariate statistical analyses such as factor analysis and principal component analysis indicated that REEs were associated and controlled by mixed origin, with similar contributions from anthropogenic and geogenic sources. The speciation study of REEs in ex-tin mining sediments using a modified five-stage sequential extraction procedure indicated that yttrium (Y), gadolinium (Gd), and lanthanum (La) were obtained at higher percentages from the adsorbed/exchanged/carbonate fraction. The average potential mobility of the REEs was arranged in a descending order: Yb > Gd > Y = Dy > Pr > Er > Tm > Eu > Nd > Tb > Sc > Lu > Ce > La, implying that under favorable conditions, these REEs could be released and subsequently pollute the environment.

  9. Sorption of REE and TPE from HNO{sub 3} solutions on strong-acid sulfonated cation exchanger KU-2

    SciTech Connect

    Chuveleva, E.A.; Kharitonov, O.V.; Firsova, L.A.

    1995-05-01

    Sorption of rare earths (REE) on the strong-acid sulfonated cation exchanger KU-2 is studied as a function of the solution acidity (0.1-2.0 M HNO{sub 3}) and REE concentration. In concentrated nitrate solutions where M(NO{sub 3}){sub 2}{sup +} and M(NO{sub 3}){sub 2}{sup +} can form and be sorbed by the cation exchanger, the capacity of the exchanger seems to increase by 20%.

  10. 87Sr/ 86Sr, 143Nd/ 144Nd and REEs in Silurian phosphatic fossils

    NASA Astrophysics Data System (ADS)

    Bertram, C. J.; Elderfield, H.; Aldridge, R. J.; Conway Morris, S.

    1992-09-01

    The feasibility of using the chemistry of phosphatic fossil material to trace palaeo-seawater composition for the Silurian has been evaluated. Contrary to Recent material, fossil fish are shown to be unreliable for Sr isotope stratigraphy. Conodonts, however, may be used by employing 0.2M HNO 3 dissolution, except for samples showing degrees of thermal maturation greater than colour alteration index (CAI) values of 2.5. Samples from the same stratigraphic levels from the U.K., Czechoslovakia, Gotland and the U.S.A. gave similar 87Sr/ 86Sr ratios, suggesting that they have recorded the original seawater value. Significant inter-specific differences occur in REE concentrations and Nd isotopic compositions of conodont elements, and Ce and Eu anomalies vary with REE content. This suggests that artefacts are introduced at the same time that large amounts of REEs are incorporated into the apatite. Preliminary results for the Sr isotopic composition of Silurian seawater are presented. Values are generally lower than previously suggested, showing an increase in 87Sr/ 86Sr from ˜ 0.70825 at 435 Ma rising to ˜ 0.70875 at 418 Ma and levelling off in the Late Silurian. The overall rate of increase in seawater ratio is about2-3 × 10 -5 Ma -1 and can be accounted for by the widespread decrease in volcanism compared with the Ordovician; a proportionally greater flux of Sr to the oceans from continental erosion of only ˜ 10% would account for the long-term increase in seawater 87Sr/ 86Sr ratio throughout the Silurian.

  11. Inter- and intra-crystal REE variations in apatite from the Bob Ingersoll pegmatite, Black Hills, South Dakota

    SciTech Connect

    Jolliff, B.L.; Papike, J.J.; Shearer, C.K. ); Shimizu, N. )

    1989-02-01

    Concentrations of rare earth elements (REE) have been measured on a suite of apatite crystals from an internally zoned granitic pegmatite enriched in Li, B, Be, F, Nb, Ta, Sn and U with a Cameca IMS 3f ion microprobe using energy filtering. An apatite specimen from the Tin Mountain pegmatite, analyzed previously by isotope dilution, was used as a standard. The chondrite-normalized pattern determined with the ion microprobe closely matches the pattern determined by isotope dilution, with maxima at Sm and Dy, and minima at Nd and Er. Apatite samples from the Bob Ingersoll pegmatite show a large range of REE patterns and concentrations. In one case, apatite crystals within millimeters show differences in REE concentrations and pattern shapes, including a switch from positive to negative Eu anomalies. These effects may be coupled with non-ideal partitioning of REE in a heterogeneous mixture of melt, aqueous fluid and crystals. REE concentrations in apatite samples from the different pegmatite zones indicate a large variation in outer zones, high concentrations near the pegmatite core, and very low concentration in the core. Patterns are flat to slightly inclined (Ce/Yb: 1 to 5), and most samples have positive Eu anomalies. The magnitude of positive Eu anomalies decreases with inward position in the pegmatite, possibly indicating a progressive increase in {line integral}O{sub 2}, and a sharp increase may be indicated by systematic Ce depletion in apatite from the pegmatite core. REE-specific volatile complexes may contribute to variations, including unusual kinks, observed in REE patterns of apatite from mineral assemblages in upper parts of the pegmatite.

  12. PARTITION COEFFICIENTS OF Hf, Zr, AND REE BETWEEN PHENOCRYSTS AND GROUNDMASSES.

    USGS Publications Warehouse

    Fujimaki, Hirokazu; Tatsumoto, Mitsunobu; Aoki, Ken-ichiro

    1984-01-01

    Partition coefficients of Hf, Zr, and REE between olivine, orthopyroxene, clinopyroxene, plagioclase, garnet, amphibole, ilmenite, phlogopite, and liquid are presented. Samples consist of megacrysts in kimberlite, phenocrysts in alkaline basalts, tholeiitic basalts and andesitic to dacitic rocks, and synthetic garnet and clinopyroxene in Hawaiian tholeiites. The Hf-Lu and Zr-Lu elemental fractionations are as large as the Lu-Sm or Lu-Nd fractionation. The Hf and Zr partition coefficients between mafic phenocrysts and liquids are smaller than the Lu partition coefficients, but are similar to the Nd or Sm partition coefficients.

  13. Pulsatile flow with heat transfer of dusty magnetohydrodynamic Ree-Eyring fluid through a channel

    NASA Astrophysics Data System (ADS)

    Shawky, Hameda Mohammed

    2009-08-01

    The flow due to the pulsatile pressure gradient of dusty non-Newtonian fluid with heat transfer in a channel is considered. The system is stressed by an external magnetic field. The non-Newtonian fluid under consideration is obeying the rheological equation of state due to Ree-Eyring’s stress-strain relation. The equations of momentum and energy have been solved by using Lightill method. The velocity and temperature distributions of the two phase of the dusty fluid are obtained. The effects of various physical parameters of distributions the problem on these distributions are discussed and illustrated graphically through a set of figure.

  14. Sm-Nd isotopic systematics and REE abundance studies of the ALH-765 eucrite

    NASA Technical Reports Server (NTRS)

    Nakamura, N.; Tatsumoto, M.; Coffrant, D.

    1983-01-01

    Analyses of Sm-Nd systematics and REE concentrations were carried out for the whole rock and mineral separates from the ALH-765 meteorite. A Sm-Nd age of 4.52 + or - 0.09 (2 sigma) b.y. and an initial Nd-143/Nd-144 ratio of 0.50675 + or 0.00011 (2 sigma) have been obtained. The previously reported Ce irregularities have been re-examined in this work. The large Ce anomalies and some minor Sm-Nd system disturbances observed for the meteorite may be interpreted as results of terrestrial weathering effects.

  15. REE-SIO2 Systematics in Mor Gabbros and Associated Plagiogranites from the Fournier Oceanic Fragment, New Brunswick, Canada

    NASA Astrophysics Data System (ADS)

    Brophy, J. G.

    2010-12-01

    Seawater influx into hot, dry MOR gabbro can initiate hydration-induced melting and the generation of intermediate to felsic partial melts collectively referred to as plagiogranite. In a recent modeling study, Brophy (2009) suggested that the REE abundances of partial melts generated in this fashion should be characterized by unique patterns of REE-SiO2 variation. Specifically, REE abundances (modeled as enrichment factors, Cl/Co) should show a positive correlation with increasing SiO2 up to around 60 wt. % followed by a steady decrease in abundance as liquid SiO2 increases to around 76%. For liquids of around 55% SiO2 the degree of enrichment is around 2 for all of the REE. However, Cl/Co in the intermediate liquids of around 60 % SiO2 steadily decreases from ~5 for La to ~3 for Yb. Simarlarly, Cl/Co in the high SiO2 liquids of around 76% SiO2 decrease from ~3 for La to ~1 for Yb. If these model predictions are correct, the REE-SiO2 systematics of any naturally occurring suite of plagiogranite and MOR gabbro could be used to assess a partial melting as opposed to crystal fractionation origin. To test the model predictions, a suite of MOR gabbros and intrusive veins of plagiogranite were collected from the Fournier Oceanic Fragment, a middle Ordovician ophiolite sequence located along the northern shore of New Brunswick, and the type exposure for plagiogranites generated by hydration-induced MOR gabbro melting (Flagler and Spray, 1991). The MOR gabbros range from 48 to 55 % SiO2 while the intrusive plagiogranites range from 57 to 78 % SiO2 (anhydrous basis). When REE abundances are plotted against whole rock SiO2 they show all of the model features described above, though the absolute abundances require an initial gabbroic source rock that is more enriched in the REE than the host gabbros themselves. This correspondence between modeled and observed REE- SiO2 variations confirms the model predictions of Brophy (2009) and suggests that REE- SiO2 systematics represent

  16. VizieR Online Data Catalog: Revised source list for the Rees 38-MHz survey (Hales+ 1995)

    NASA Astrophysics Data System (ADS)

    Hales, S. E. G.; Waldram, E. M.; Rees, N.; Warner, P. J.

    1994-11-01

    We present a revised machine-readable source list for the Rees 38-MHz (or '8C') survey with improved positions and no redundancy. The Rees 38-MHz survey covers an area of about 1 sr north of declination +60 degrees. The angular resolution is 4.5 x 4.5cosec(Dec) arcmin**2 and the limiting flux density over much of the survey area is about 1 Jy. Both of these figures are an improvement by nearly an order of magnitude on previous surveys at this frequency. Users of these data should consult and cite the original survey paper by Rees as primary reference (1990MNRAS.244..233R) with the present publication (1995MNRAS.274..447H) as a supplementary revision. The recommended style of reference is thus : "The revised Rees 38-MHz survey (Rees 1990, catalogue revised Hales et. al 1995)." Note that for interest the source list includes data on some sources at declinations lower than +60 degrees, but that the right ascension coverage is not complete below +60 degrees. (1 data file).

  17. Hf, Zr, and REE partition coefficients between ilmenite and liquid - Implications for lunar petrogenesis

    NASA Technical Reports Server (NTRS)

    Nakamura, Y.; Fujimaki, H.; Nakamura, N.; Tatsumoto, M.; Mckay, G. A.

    1986-01-01

    Partition coefficients (D) between ilmenite and coexisting liquid were determined under near-lunar conditions for Hf, Zr, and REE. Through isotope dilution analysis, ilmenite D values of 0.41 and 0.33 were obtained for Hf and Zr respectively, values significantly lower than those of ilmenite from a kimberlite megacryst. Partition coefficients of REE for the synthesized ilmenite are slightly smaller than those of ilmenite from the kimberlite megacryst, and the lunar (Lu) partition coefficient is 0.056. These results suggest that ilmenite was significant in the lunar-Hf evolution of lunar mare basalts. Using lunar and Hf D values for ilmenite, the Lu-Hf evolution of lunar cumulates and the coexisting magma was examined for various crystallization sequences. The Lu-Hf variation trend of most high-Ti mare basalts is explained by a small degree of partial cumulate melting, though a higher degree is required to explain the variation of very low-Ti basalts, green glass, and Apollo 12 low-Ti basalts. Apollo 15 low-Ti basalts may require chromite crystallization as well.

  18. Globular and Optically Transparent Photonic Crystals Based on 3D-opal Matrix and REE

    NASA Astrophysics Data System (ADS)

    Ivicheva, S. N.; Kargin, Yu. F.; Gorelik, V. S.

    By repeatedly filling the octahedral and tetrahedral pores of 3D-silica opal matrices with silica sol doped with rare-earth elements with subsequent heat treatment globular photonic crystals filled with mesoporous glass and optically transparent photonic crystals (quantytes) containing 10-30 ppm REE were produced, depending on the annealing temperature. Voids of fcc lattice formed by amorphous spherical globules of SiO2 in globular photonic crystals are filled (up to 70%) by mesoporous glass doped with rare earth elements. Pores in the transparent photonic crystals disappear during sintering of globules of silica and mesoporous glass, but the periodic arrangement of REE-enriched silica areas (quantum dots) is retained. The reflection and luminescence spectra of photonic crystals filled with sols doped with europium Eu3+ and terbium Tb3+ were experimentally studied. A significant increase in the photoluminescence intensity of Eu3+ ions at the approach of the spectral position of the transition 5D0 → 7F2 to the edge of the bandgaps of the photonic crystal was determined. The authors come to the conclusion that a lowering of the threshold for lasing transitions in ions of rare elements is possible.

  19. Discrimination of sediment provenance in the Yellow Sea: Secondary grain-size effect and REE proxy

    NASA Astrophysics Data System (ADS)

    Jung, Hoi-Soo; Lim, Dhongil; Jeong, Do-Hyun; Xu, Zhaokai; Li, Tiegang

    2016-06-01

    This study analyzed grain size and elemental concentrations (Al, Mg, Fe, and rare earth elements (REEs)) in 91 surface sediments to elucidate sediment provenance in the Yellow Sea. Elemental concentrations were normalized by Al concentration (Celement/CAl) to minimize the sediment grain-size effect (GSE). However, noticeable linear relationships between Al concentration (or mean grain size) and the ratio (e.g., Mg/Al or Fe/Al) appeared unexpectedly in pair diagrams. The spatial distribution patterns of Fe/Al and Mg/Al ratios were also similar to the pattern of mean grain size. This implies that the GSE was not removed completely, even after the normalization process. Thus, great care must be taken when applying the ratios of Celement/CAl as a proxy of sediment provenance. To improve provenance discrimination of the sediments in the Yellow Sea, the difference between the REE distribution patterns of Chinese and Korean river sediments, expressed as δ (δ = REE∗(La) - REE∗(Lu)), was calculated, and the spatial distribution patterns of the δ values were mapped. The δ values gradually increased from the western to the eastern part of the Yellow Sea, except for low δ values in the southeastern part of the Yellow Sea. This result indicates that the majority of Chinese and Korean river sediments are accumulating near to their respective coasts, except for a deposit along the southwestern coast of Korea in which a considerable amount of sediment from Chinese rivers has been accumulating.

  20. The evolution of immiscible silicate and fluoride melts: Implications for REE ore-genesis

    NASA Astrophysics Data System (ADS)

    Vasyukova, O.; Williams-Jones, A. E.

    2016-01-01

    The Mid-Proterozoic peralkaline Strange Lake pluton (Québec-Labrador, Canada) exhibits extreme enrichment in high field strength elements (HFSE), including the rare earth elements (REE), particularly in pegmatites. On the basis of a study of melt inclusions, we proposed recently that fluoride-silicate melt immiscibility played an important and perhaps dominant role in concentrating the REE within the pluton. Here we present further evidence for silicate-fluoride immiscibility at Strange Lake from a sample of the hypersolvus granite, which contains an inclusion composed largely of REE and HFSE minerals. The inclusion (∼5 cm in diameter) comprises a narrow rim containing chevkinite-(Ce) and zircon in a fluorite matrix, a core of fluorbritholite-(Ce) and bastnäsite-(Ce) and a transition zone between the rim and the core consisting of a fine-grained intergrowth of bastnäsite-(Ce), gagarinite-(Y) and fluorite. We propose that the inclusion formed as a result of silicate-fluoride immiscibility, which occurred early in the emplacement history of the Strange Lake pluton, and that it represents the fluoride melt. After separation of the two melts, the boundary between them acted as a locus of crystallisation, where crystals formed repeatedly due to heterogeneous (surface catalysed) nucleation. Zircon crystallised shortly after melt phase separation, and was followed by the growth of perthite together with arfvedsonite and quartz. As a result, the silicate melt surrounding the fluoride inclusion became enriched in volatiles that facilitated crystallisation of progressively larger crystals in the inclusion; large crystals of arfvedsonite and perthite were succeeded by even larger crystals of quartz. Massive crystallisation of chevkinite-(Ce) followed, forming the rim of the inclusion. The fluoride melt, which constituted the matrix to the silicate minerals and chevkinite-(Ce), crystallised after chevkinite-(Ce), forming fluorbritholite-(Ce) and fluorite. Aqueous fluid

  1. Al-26, Pu-244, Ti-50, REE, and trace element abundances in hibonite grains from CM and CV meteorites

    NASA Technical Reports Server (NTRS)

    Fahey, A. J.; Mckeegan, K. D.; Zinner, E.; Goswami, J. N.

    1987-01-01

    Hibonites from the CM meteorites Murchison, Murray, and Cold Bokkeveld, and hibonites and Ti-rich pyroxene from the CV chondrite Allende are studied. Electron microprobe measurements of major element concentrations and track and ion probe measurements of Mg and Ti isotopic ratios, rare earth elements (REEs), and trace element abundances are analyzed. Correlations between isotopic anomalies in Ti, Al-26, Pu-244, and Mg-26(asterisk) are examined. Ti isotopic anomalies are compared with REE and trace element abundance patterns. Reasons for the lack of Al-26 in the hibonites are investigated and discussed. It is observed that there is no correlation between the Ti isotopic compositions, and the presence of Mg-26(asterisk), Pu-244, and REE and trace element patterns in individual hibonite samples. The data reveal that hibonites are not interstellar dust grains but formed on a short time scale and in localized regions of the early solar system.

  2. Closure temperature in cooling bi-mineralic systems: I. Definition and with application to REE-in-two-pyroxene thermometer

    NASA Astrophysics Data System (ADS)

    Yao, Lijing; Liang, Yan

    2015-08-01

    Closure temperature is an important concept to many diffusion related problems involving cooling. The basic idea and formulation were outlined in the seminal work of Dodson for cooling mono-mineralic systems. The Dodson's equation has been widely used to calculate closure temperatures for igneous and metamorphic rocks that contain more than one mineral. The purpose of this study is to examine closure temperatures in cooling bi-mineralic systems and to investigate the physical meaning of temperatures calculated using the REE-in-two-pyroxene thermometer. We conduct numerical simulations of diffusive redistribution of trace elements between two coexisting minerals under prescribed cooling using temperature-dependent diffusion coefficients and mineral-mineral partition coefficients. Following Dodson's treatment, the closure temperature in bi-mineralic systems can be defined by the evolution of either average trace element concentrations in the two minerals or their ratio. The latter defines an effective partition coefficient. Closure temperatures calculated based on the two definitions are compared for a range of cooling rates, grain sizes, mineral proportions, and temperature-dependent partition coefficients and diffusion coefficients. Temperatures defined by the effective partition coefficient are recommended. Application to diffusive redistribution of rare earth elements (REE) in orthopyroxene-clinopyroxene systems demonstrates that closure temperature differences among REE are small and hence their average value may be used as the closure temperature for the cooling two-pyroxene system. The average closure temperature of REE in the two-pyroxene system is essentially the same as the temperature calculated using the REE-in-two-pyroxene thermometer and practically independent of pyroxene modal abundance in the system. Differences in temperatures calculated using the REE- and major element-based two-pyroxene thermometers can be used to infer cooling rate of two

  3. U-Th-Pb ion microprobe analysis of monazite from the Paleoproterozoic Karrat rare earth element (REE) deposit, western Greenland

    NASA Astrophysics Data System (ADS)

    Mott, A.; Grove, M.; Bird, D. K.

    2012-12-01

    The Karrat rare earth element (REE) deposit is located at 72°N on the Niaqornakavsak peninsula of Qeqertarssuq Island on the western coast of Greenland. Metasomatic alteration of an amphibolite host rock by carbonatite derived fluids resulted in REE mineralization in the Karrat Isfjord area. REE in the mineralization are primarily found in bastnasite, allanite, and monazite. In-situ analysis of monazite was conducted on samples obtained from three sites of mineralization: (1) the primary deposit at Niaqornakavsak consisting of a single distinct ~30m thick unit; (2) at Umiamako Nuna 7 km to the east of Niaqornakavsak where the majority of REE mineralization occurs within the first 20m of the surface; and (3) a 6m thick REE-rich vein 100m below the surface at Umiamako Nuna. Formation ages for monazite at Niaqornakavsak, Umiamako Nuna (surface), and Umiamako Nuna (vein) have been calculated using 207Pb/206Pb, 206Pb/238U, and 208Pb/232Th isotope ratios. Multiple isotope ratios were examined to determine the ideal method of monazite analysis based on the inherent issues of low U content of monazite, difficulties measuring 204Pb, common Pb corrections, and peak interferences resulting from high concentrations of REE. 208Pb/232Th analysis resulted in the best precision and smallest spread of values. Energy filtering was applied to 208Pb/232Th analyses in an effort to reduce interferences at several peaks. Although all three isotope ratio analyses result in a Paleoproterozoic age similar to the timing of convergence of the North Atlantic craton, Rae craton, and Aasiat domain as well as the emplacement of the Prøven Igneous Complex in Greenland (1.95-1.80Ga), the values range between 1.7-1.9Ga depending on the isotope ratio.

  4. Carbonate-silicate melt immiscibility, REE mineralising fluids, and the evolution of the Lofdal Intrusive Suite, Namibia

    NASA Astrophysics Data System (ADS)

    Bodeving, Sarah; Williams-Jones, Anthony E.; Swinden, Scott

    2017-01-01

    The Lofdal Intrusive Suite, Namibia, consists of calcio-carbonatite and silica-undersaturated alkaline intrusive rocks ranging in composition from phono-tephrite to phonolite (and nepheline syenite). The most primitive of these rocks is the phono-tephrite, which, on the basis of its Y/Ho and Nb/Ta ratios, is interpreted to have formed by partial melting of the mantle. Roughly linear trends in major and trace element contents from phono-tephrite to phonolite and nepheline syenite indicate that the latter two rock types evolved from the phono-tephrite by fractional crystallisation. The nepheline syenite, however, has a lower rare earth element (REE) content than the phonolite. The carbonatite has a primitive mantle-normalised REE profile roughly parallel to that of the silica-undersaturated alkaline igneous rocks, although the absolute REE concentrations are higher. Like the phono-tephrite, it also has a mantle Y/Ho ratio. However, the Nb/Ta and Zr/Hf ratios are significantly higher. Moreover, the carbonatite displays strong negative Ta, Zr and Hf anomalies on spidergrams, whereas the silicate rocks display positive anomalies for these elements. Significantly, this behaviour is predicted by the corresponding carbonatite-silicate melt partition coefficients, as is the behaviour of the REE. Based on these observations, we interpret the carbonatite to represent an immiscible liquid that exsolved from the phono-tephrite or possibly the phonolite melt. The result was a calcio-carbonatite that is enriched in the heavy REE (HREE) relative to most other carbonatites. Fluids released from the corresponding magma are interpreted to have been the source of the REE mineralisation that is currently the target of exploration.

  5. Characterization of REE-Bearing Minerals and Synthetic Materials Using High Resolution Ultraviolet to Near-Infrared Reflectance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hoefen, T. M.; Livo, K. E.; Giles, S. A.; Lowers, H. A.; Swayze, G. A.; Taylor, C. D.; Verplanck, P. L.; Emsbo, P.; Koenig, A.; Mccafferty, A. E.

    2014-12-01

    Diagnostic crystal field 4fn-4fn transition features in the ultraviolet (UV) to near-infrared (NIR) region of the electromagnetic spectrum have been observed in many common rare earth element (REE)-bearing minerals. The partial filling of the 4f electron shell combined with a shielding effect caused by the fully filled 5s25p6-electron shells, which weaken any effects from external magnetic or electric fields on the electrons, makes rare earth ions unique. The narrow absorption features occur as a result of parity forbidden transitions and crystal field splitting of the trivalent REEs, and since they are well shielded, only subtle wavelengths shifts are seen in their spectral features. Synthetic single REE phosphates, carbonates, oxides, hydroxides and glasses have been measured in the lab to help identify absorption band positions that are characteristic of each REE as they occur in different minerals. Because spectral resolution is critical to identifying shifts in the absorption band positions, these materials have been measured on several different high resolution spectrometers. Using a combination of Ocean Optics USB 2000+ UV-VIS, USB2000+ VIS-NIR and ASD FS 4 spectrometers we have characterized REE-bearing materials from 0.2 to 2.5 microns with a spectral resolution of ~2 nm between 0.2 and 1.0 microns and 11 to 12 nm between 1.0 and 2.5 microns. Results to date suggest that wavelength shifts and variations in the degree of crystal field splitting allow spectral differentiation between REE-bearing minerals. To support these results, a comprehensive suite of marine phosphates, paleo-beach placers, IOCG deposits, alkaline to peralkaline igneous complexes, pegmatites associated with alkaline magmas and carbonatite intrusives, have been measured and included in our database. Core, rock chips, billets, sediment samples and grab samples were manually scanned to identify the most intense or spectrally different REE features. While REE-bearing minerals have been

  6. REE in skarn systems: A LA-ICP-MS study of garnets from the Crown Jewel gold deposit

    NASA Astrophysics Data System (ADS)

    Gaspar, Miguel; Knaack, Charles; Meinert, Lawrence D.; Moretti, Roberto

    2008-01-01

    Metamorphic and magmatic garnets are known to fractionate REE, with generally HREE-enriched patterns, and high Lu/Hf and Sm/Nd ratios, making them very useful as geochemical tracers and in geochronological studies. However, these garnets are typically Al-rich (pyrope, almandine, spessartine, and grossular) and little is known about garnets with a more andraditic (Fe 3+) composition, as frequently found in skarn systems. This paper presents LA-ICP-MS data for garnets from the Crown Jewel Au-skarn deposit (USA), discusses the factors controlling incorporation of REE into garnets, and strengthens the potential of garnet REE geochemistry as a tool to help understand the evolution of metasomatic fluids. Garnets from the Crown Jewel deposit range from Adr 30Grs 70 to almost pure andradite (Adr >99). Fe-rich garnets (Adr >90) are isotropic, whereas Al-rich garnets deviate from cubic symmetry and are anisotropic, often showing sectorial dodecahedral twinning. All garnets are extremely LILE-depleted, Ta, Hf, and Th and reveal a positive correlation of ΣREE 3+ with Al content. The Al-rich garnets are relatively enriched in Y, Zr, and Sc and show "typical" HREE-enriched and LREE-depleted patterns with small Eu anomalies. Fe-rich garnets (Adr >90) have much lower ΣREE and exhibit LREE-enriched and HREE-depleted patterns, with a strong positive Eu anomaly. Incorporation of REE into garnet is in part controlled by its crystal chemistry, with REE 3+ following a coupled, YAG-type substitution mechanism ([X]-1VIII[REE]+1VIII[Si]-1IV[Z]+1IV), whereas Eu 2+ substitutes for X 2+ cations. Thermodynamic data (e.g., Hmixing) in grossular-andradite mixtures suggest preferential incorporation of HREE in grossular and LREE in more andraditic compositions. Variations in textural and optical features and in garnet geochemistry are largely controlled by external factors, such as fluid composition, W/ R ratios, mineral growth kinetics, and metasomatism dynamics, suggesting an overall system

  7. The Obtaining of Nano Oxide Systems SiO2-REE with Alkoxide Technology

    NASA Astrophysics Data System (ADS)

    Amelina, Anna; Grinberg, Evgenii

    A lot of oxides systems with REE as dopants are used in catalytic processes in organic synthesis. They are very perspectives as thermostable coating in aerospace technics. These systems are usually based on silicon or aluminium oxides and doped with rare-earth elements. This systems can be produced by different methods. One of the most perspective of them is “sol-gel”-method with silicium, aluminium and rare-earth alkoxides as a precursor of doped silica and alumina, or their derivatives. Thus the obtaining of composite SiO _{2} - REE oxide materials by the hydrolysis doped with rare-earth elements was suggested. Some of alcoholate derivatives such as El(OR)n were used in this processes. The SiO _{2}- REE oxides were precipitated during the sol-gel process, where tetraethoxysilane (TEOS) as used as SiO _{2} sources. Also it is known that alkoxides of alkali metals, including lithium alkoxides, are widely used in industry and synthetic chemistry, as well as a source of lithium in various mixed oxide compositions, such as lithium niobate, lithium tantalate or lithium silicate. Therefore, we attempted to obtain the lithium silicate, which is also doped with rare-earth elements. Lithium silicate was obtained by alkaline hydrolysis of tetraethoxysilane with lithium alkoxide. Lithium alkoxide were synthesized by dissolving at metal in the corresponding alcohol are examined. The dependence of the rate of dissolving of the metal on the method of mixing of the reaction mixture and the degree of metal dispersion was investigated. The mathematical model of the process was composed and also optimization of process was carried out. Some oxide SiO _{2}, Al _{2}O _{3} and rare-earth nanostructured systems were obtained by sol-gel-method. The size of particle was determined by electron and X-ray spectroscopy and was in the range of 5 - 15 nm. Purity of this oxide examples for contaminating of heavy metals consists n.(1E-4...1E-5) wt%. Sols obtained by this method may be used

  8. Carbonatites of the World, Explored Deposits of Nb and REE - Database and Grade and Tonnage Models

    USGS Publications Warehouse

    Berger, Vladimir I.; Singer, Donald A.; Orris, Greta J.

    2009-01-01

    This report is based on published tonnage and grade data on 58 Nb- and rare-earth-element (REE)-bearing carbonatite deposits that are mostly well explored and are partially mined or contain resources of these elements. The deposits represent only a part of the known 527 carbonatites around the world, but they are characterized by reliable quantitative data on ore tonnages and grades of niobium and REE. Grade and tonnage models are an important component of mineral resource assessments. Carbonatites present one of the main natural sources of niobium and rare-earth elements, the economic importance of which grows consistently. A purpose of this report is to update earlier publications. New information about known deposits, as well as data on new deposits published during the last decade, are incorporated in the present paper. The compiled database (appendix 1; linked to right) contains 60 explored Nb- and REE-bearing carbonatite deposits - resources of 55 of these deposits are taken from publications. In the present updated grade-tonnage model we have added 24 deposits comparing with the previous model of Singer (1998). Resources of most deposits are residuum ores in the upper part of carbonatite bodies. Mineral-deposit models are important in exploration planning and quantitative resource assessments for two reasons: (1) grades and tonnages among deposit types vary significantly, and (2) deposits of different types are present in distinct geologic settings that can be identified from geologic maps. Mineral-deposit models combine the diverse geoscience information on geology, mineral occurrences, geophysics, and geochemistry used in resource assessments and mineral exploration. Globally based deposit models allow recognition of important features and demonstrate how common different features are. Well-designed deposit models allow geologists to deduce possible mineral-deposit types in a given geologic environment, and the grade and tonnage models allow economists to

  9. Jabal Hamra REE-mineralized silexite, Hijaz region, Kingdom of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Jackson, Norman J.; Douch, Colin J.

    The Jabal Hamra silexite, a crescent-shaped stock 300 m long by 100 m wide, averages over 6000 ppm combined REE and is the Kingdom's highest-grade resource of these elements. It is anomalously radioactive (total-count gamma radiation 1000-3000 cps), has high average contents of U (75 ppm) and Th (263 ppm) and is also enriched in Nb, Zr, Y, Sn and Ta. The silexite crystallized as a pressure-quenched rock resembling aplite, and was subsequently pervasively cataclased. It was derived by differentiation of a quartz alkali-feldspar syenite magma. Petrologic continuity can be demonstrated from quartz alkali-feldspar syenite through leucocratic and amphibole-bearing alkali-feldspar granite to silexite. Although the geochemical signature of the mineralization resembles that of mineralized Arabian alkali granites, the nature of the associated rocks and therefore the genesis of the deposit are significantly different.

  10. Evaporatic-source model for igneous-related Fe oxide (REE-Cu-Au-U) mineralization

    SciTech Connect

    Barton, M.D.; Johnson, D.A.

    1996-03-01

    We propose that many igneous-related Fe oxide-rich (REE-Cu-Au-U-bearing) deposits form by hydrothermal processes involving evaporitic ligand sources, either coeval salars or older evaporites. These deposits are abundant in both Phanerozoic and Proterozoic extensional continental and continent-margin settings. They commonly form in global arid zones, but they also occur where magmatism is superimposed upon older evaporites. Magmatic compositions exert only second-order control, mainly on alteration mineralogy and on element abundances. Hot S-poor brines generated by interaction with evaporitic materials are consistent with geologic settings and help rationalize the distinctive element enrichments (siderophile, lithophile) and hydrothermal alteration (sodic, locally alkaline) found in these systems. This model contrasts with immiscible oxide melt and magmatic-hydrothermal origins commonly proposed for these deposits, although all three mechanisms can occur. 31 refs., 3 figs., 1 tab.

  11. A synthesis of mineralization styles with an integrated genetic model of carbonatite-syenite-hosted REE deposits in the Cenozoic Mianning-Dechang REE metallogenic belt, the eastern Tibetan Plateau, southwestern China

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Hou, Zengqian

    2017-04-01

    The Cenozoic Mianning-Dechang (MD) rare earth element (REE) belt in eastern Tibet is an important source of light REE in southwest China. The belt is 270 km long and 15 km wide. The total REE resources are >3 Mt of light rare earth oxides (REO), including 3.17 Mt of REO at Maoniuping (average grade = 2.95 wt.%), 81,556 t at Dalucao (average grade = 5.21 wt.%), 0.1 Mt at Muluozhai (average grade = 3.97 wt.%), and 5764 t of REO at Lizhuang (average grade = 2.38 wt.%). Recent results from detailed geological surveys, and studies of petrographic features, ore-forming ages, ore forming conditions, and wallrock alteration are synthesized in this paper. REE mineralization within this belt is associated with carbonatite-syenite complexes, with syenites occurring as stocks intruded by carbonatitic sills or dikes. The mineralization is present as complex vein systems that contain veinlet, stringer, stockwork, and brecciated pipe type mineralization. Carbonatites in these carbonatite-related REE deposits (CARDs) are extremely rich in light REEs, Sr (>5000 ppm), and Ba (>1000 ppm), and have low Sr/Ba and high Ba/Th ratios, and radiogenic Sr-Nd isotopic compositions. These fertile magmas, which may lead to the formation of REE deposits, were generated by the partial melting of sub-continental lithospheric mantle (SCLM) that was metasomatized by REE- and CO2-rich fluids derived from subducted marine sediments. We suggest that this refertilization occurred along cratonic margins and, in particular, at a convergent margin where small-volume carbonatitic melts ascended along trans-lithospheric faults and transported REEs into the overlying crust, leading to the formation of the CARDs. The formation of fertile carbonatites requires a thick lithosphere and/or high pressures (>25 kbar), a metasomatized and enriched mantle source, and favorable pathways for magma to ascend into the overlying crust where REE-rich fluids exsolve from cooling magma. The optimal combination of these three

  12. Preservation of REE and Fe isotopes in altered stromatolites and the paleo-environmental record

    NASA Astrophysics Data System (ADS)

    Nies, S. M.; Shapiro, R. S.; Lalonde, S.

    2015-12-01

    Geochemical proxies are increasingly being used to unravel ancient ecosystems and environmental perturbations back to the earliest rock record on Earth. Along with more traditional fossils (stromatolites) and other biosignatures (e.g., lipids), the geochemical record is used specifically to evaluate biogenecity and to understand oxygenation of the atmosphere and ocean in the Archean and Paleoproterozoic. However, the effects of diagenesis, metamorphism, and other modes of secondary alteration are still poorly constrained, particularly as technological advances allow us to expand farther across the periodic table. Our study focused on the robustness and preservation of rare earth element (REE) and Fe isotope compositions of two stromatolitic units that have undergone contact and regional metamorphism. 18 samples were collected from cores, open pit mines, and field locations in Minnesota and Ontario from silicified iron formation (Biwabik-Gunflint formations). The samples were carefully constrained to one of two meter-scale stromatolitic units. Metamorphic grade ranged from essentially unmetamorphosed through prehnite-pumpellyite up to amphibolite (fayalite+hypersthene). Samples were also collected that represented deep secondary weathering, likely related to Cretaceous climatic extremes. Polished samples were first analyzed by electron microprobe and selected samples were further analyzed via laser ablation HR-ICP-MS to constrain trace element (n=13) and Fe isotopic variations (n=8). Preliminary results indicate that transition metal concentrations are surprisingly resilient to high-temperature metamorphic recrystallization. REE concentrations were analyzed in individual iron oxide grains, with full resolution (La to Lu) achieved for some samples and partial resolution (La to Nd) achieved for all samples. Core samples exhibited a relatively stable positive Ce anomaly occurring from low to extremely high alteration. Outcrop and mine samples indicate a shift from a

  13. REE profiles in continuous leach ICP-MS (CL-ICP-MS) experiments in soil linked to REE profiles in surface water in the Koiliaris River Critical Zone Observatory (CZO), Crete, Greece

    NASA Astrophysics Data System (ADS)

    Roskam, Gerlinde; Verheul, Marc; Moraetis, Daniel; Giannakis, George; Nikolaidis, Nikolaos

    2014-05-01

    The Koiliaris River CZO watershed is situated 25 km east from the city of Chania, Crete, Greece. The total surface area of the watershed is 130 km2 with a total length of 36 km and a maximum altitude difference of 2120 m. The outcropping rocks at higher altitudes are Plattenkalke nappe topped by the Trypali nappe, which are mainly bedded- and recrystallized brecciated un-bedded limestones and contain large karstic sinkholes. The Trypali nappe is topped by the Western Crete phyllites and is comprised of quartz and micaceous minerals. At lower elevation neogene marls and marly limestones and recent alluvial sand and conglomerate deposits are dominating. The hydrology at the Koiliaris River watershed is dominated by spring outflow at the limestone- fluvial sediment boundaries at lower elevation (<200 m), (largely) dry rivers through the limestone nappes and one ephemeral river on the top of the phyllites. The springs at lower altitudes are fed by rain and the snow melt from the karstic aquifers. Stylos spring is the main water supply for the Koiliaris River while other tributaries are mainly in karstic areas and flow is limited. Throughout the watershed at 5 locations soil samples were taken at two different depths and water samples in various springs and rivers were collected and REE were analysed. Progressively reactive solvents (0.01M CaCl, 0.1M HNO3, 1M HNO3, 4M HNO3) were pumped through the sample column, and then directly into the ICP-MS. All the major and the rare earth elements (REE) were continuously measured. The REE concentrations are normalized to NASC and are mineral specific. The mineral specific REE profiles can be linked to the REE profiles measured in the springs and rivers in the watershed.

  14. Effects of organic ligands on fractionation of rare earth elements (REEs) in hydroponic plants: an application to the determination of binding capacities by humic acid for modeling.

    PubMed

    Ding, ShiMing; Liang, Tao; Zhang, ChaoSheng; Yan, JunCai; Zhang, ZiLi

    2006-12-01

    Previous studies have revealed the fractionation processes of rare earth elements (REEs) in hydroponic plants, with a heavy REE (HREE, the elements from Gd to Lu) enrichment in leaves. In this study, effects on the HREE enrichment in soybean leaves with additions of carboxylic acids (acetate, malate, citrate, NTA, EDTA and DTPA) and two soil humic acids (HAs) were investigated. REE speciation in carboxylic acid and HA solutions was simulated using Visual MINTEQ and Model V, respectively. The results showed that the effects caused by carboxylic acids were strongly dependent on the differences between their binding strengths for light REEs (LREEs, the elements from La to Eu) and those for HREEs. A good correlation existed between these effects and the changes of free REE ions in solutions. This relationship was also observed for the HA treatments, provided that the intrinsic equilibrium constants of REEs for cation-proton exchange with HA (i.e., pK(MHA)) in Model V were estimated using a free-energy relationship with the stability constants for REE complexation with lactic acid. It is suggested that this set of pK(MHA) values is more suitable for use in Model V for the simulation of REE complexation with HA.

  15. REE Sorption Study of Sieved -50 +100 mesh Media #1 in Brine #1 with Different Starting pH's at 70C

    SciTech Connect

    Gary Garland

    2015-07-21

    This dataset described shaker table experiments ran with sieved -50 +100 mesh media #1 in brine #1 that have 2ppm each of the 7 REE metals at different starting pH's of 3.5, 4.5, and 5.5. The experimental conditions are 2g media to 150mL of REE solution, at 70C.

  16. Using Rare Earth Element (REE) tracers to identify perferential micro-sites of post-fire aeolian erosion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant communities in desert environments are spatially anisotropic. We applied Rare Earth Element (REE) tracers to different landscape positions of an anisotropic Northern Chihuahua Desert ecosystem in an effort to study preferential sediment source areas. We delineated three 0.5 m by 6 m plots of...

  17. Sm-Nd dating and REE Composition of scheelite for the Honghuaerji scheelite deposit, Inner Mongolia, Northeast China

    NASA Astrophysics Data System (ADS)

    Guo, Zhijun; Li, Jinwen; Xu, Xinying; Song, Zeyou; Dong, Xuzhou; Tian, Jing; Yang, Yuncheng; She, Hongquan; Xiang, Anping; Kang, Yongjian

    2016-09-01

    Sm-Nd analyses of seven scheelite samples from scheelite-quartz veins in the Honghuaerji scheelite deposit produce a well-defined linear array on an isochron diagram with a mean square weighted deviation (MSWD) of 0.87 corresponding to an age of 178.4 ± 2.9 Ma with εNd(t) = + 1.50. This age is interpreted to represent the age of scheelite mineralization. The scheelite Sm-Nd age is in good agreement with U-Pb ages obtained from a mineralization-related granite (179.4 178.6 Ma), indicating that there is no apparent age gap between granite crystallization and ore formation. Rare earth element (REE) abundances in the scheelite were determined by in situ laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and the scheelite samples contain elevated REE concentrations with total ΣREE + Y contents in the range of 3339 to 6321 ppm. The chondrite-normalized REE distribution patterns of all scheelites are middle REE (MREE)-enriched, with strong negative Eu-anomalies (Eu/Eu* = 0.09 0.23). The REE characteristics of the Honghuaerji scheelite suggest that REE3 + substituted into the Ca site along with Na and Nb (dominated by Na), whereas Eu is predominantly present as Eu2 + in the scheelite and may have crystallized from relatively reduced fluids. All sulfur isotope data (δ34S) for sulfide separates range from + 2.0 to + 3.8‰, with an average of 3.2‰. Measured 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios vary from 18.243 to 18.451, 15.494 to 15.574, and 37.933 to 38.340, respectively. On the basis of common Sr-Nd-Pb-Hf isotopic characteristics between the scheelite and the host granite and the positive initial Nd isotope ratios (+ 1.46 - + 1.52), low 87Sr/86Sr ratios (0.704983-0.705297) in the scheelites, it is inferred that the hydrothermal fluids responsible for tungsten mineralization at Honghuaerji were of magmatic origin with a mantle-derived signature. Based on the regional geology, tectonic evolution, and geochemical evidence, the

  18. The behaviour of REEs in Thailand's Mae Klong estuary: Suggestions from the Y/Ho ratios and lanthanide tetrad effects

    NASA Astrophysics Data System (ADS)

    Censi, P.; Sprovieri, M.; Saiano, F.; Di Geronimo, S. I.; Larocca, D.; Placenti, F.

    2007-02-01

    The concentrations of Rare Earth Elements and yttrium (REY) were measured in dissolved phase, in suspended particulate matter (SPM) and in sediments in seven sampling stations in the Mae Klong estuarine system (Inner Thailand Gulf) in order to study their behaviour and distribution pattern. The analysed samples generally show high Rare Earth Element (REE) content in the dissolved phase, with high Medium Rare Earth Elements (MREEs) and Y enrichments in the shale-normalized pattern (versus PAAS). These chemical features are interpreted in terms of direct influences of weathering processes of REE-rich minerals (e.g., phosphates), which abundantly out-crop in the Mae Klong watershed. These large MREE enrichments also suggest that dissolved sulphate complexes play an important role in the dissolved REE fate close to the marine coastal system. The shale normalized REEs and Y/Ho ratios additionally indicate a direct REY co-precipitation with Fe-oxyhydroxides along the river path and consequent adsorption, as coating, onto FeOOH surfaces. The REY behaviour in SPM appears strongly influenced by Al, Fe and Mn content, suggesting that the formation of an authigenic Fe, Mn oxyhydroxides and aluminosilicate particulate leads to REY adsorption and/or co-precipitation. The observed variations in the Y/Ho ratios suggest that different Y-Ho fractionation processes take place in the studied estuarine system. Strong similarities among chondrite-normalized REE patterns in both sediments and granitic rocks out-cropping in the surrounding regions suggest a generic relationship between the two groups of materials.

  19. Hydrothermal mobilization of pegmatite-hosted REE and Zr at Strange Lake, Canada: A reaction path model

    NASA Astrophysics Data System (ADS)

    Gysi, Alexander P.; Williams-Jones, Anthony E.

    2013-12-01

    Petrological and geochemical observations of pegmatites in the Strange Lake pluton, Canada, have been combined with numerical simulations to improve our understanding of fluid-rock interaction in peralkaline granitic systems. In particular, they have made it possible to evaluate reaction paths responsible for hydrothermal mobilization and mineralization of rare earth elements (REE) and Zr. The focus of the study was the B-Zone in the northwest of the pluton, which contains a pegmatite swarm and is the target of exploration for an economically exploitable REE deposit. Many of the pegmatites are mineralogically zoned into a border consisting of variably altered primary K-feldspar, arfvedsonite, quartz, and zirconosilicates, and a core rich in quartz, fluorite and exotic REE minerals. Textural relationships indicate that the primary silicate minerals in the pegmatites were leached and/or replaced during acidic alteration by K-, Fe- and Al-phyllosilicates, aegirine, hematite, fluorite and/or quartz, and that primary zirconosilicates (e.g., elpidite) were replaced by gittinsite and/or zircon. Reaction textures recording coupled dissolution of silicate minerals and crystallization of secondary REE-silicates indicate hydrothermal mobilization of the REE. The mobility of the light (L)REE was limited by the stability of REE-F-(CO2)-minerals (basnäsite-(Ce) and fluocerite-(Ce)), whereas zirconosilicates and secondary gadolinite-group minerals controlled the mobility of Zr and the heavy (H)REE. Hydrothermal fluorite and fluorite-fluocerite-(Ce) solid solutions are interpreted to indicate the former presence of F-bearing saline fluids in the pegmatites. Numerical simulations show that the mobilization of REE and Zr in saline HCl-HF-bearing fluids is controlled by pH, ligand activity and temperature. Mobilization of Zr is significant in both saline HF- and HCl-HF-bearing fluids at low temperature (250 °C). In contrast, the REE are mobilized by saline HCl-bearing fluids

  20. Reaction of seawater with fresh mid-ocean ridge gabbro creates ';atypical' REE pattern and high REE fluid fluxes: Experiments at 425 and 475 °C, 400 and 1000 bar

    NASA Astrophysics Data System (ADS)

    Beermann, O.; Garbe-Schönberg, D.; Holzheid, A. D.

    2013-12-01

    High-temperature MOR hydrothermalism significantly affects ocean chemistry. The Sisters Peak (SP) hydrothermal field at 5°S on the slow-spreading Mid-Atlantic Ridge (MAR) emanates fluids >400°C [1] that have high concentrations of H2, transition metals, and rare earth elements (REE) exhibiting ';atypical' REE pattern characterized by depletions of LREE and HREE relative to MREE and no Eu anomaly [2]. This is in contrast to the ';typical' LREE enrichment and strong positive Eu anomaly known from many MOR vent fluids observed world-wide [e.g., 3]. Besides temperature, the seawater-to-rock ratio (w/r ratio) has significant control on the fluid chemistry [e.g., 4, 5]. To understand how vent fluid REE-signatures are generated during water-rock interaction processes we reacted unaltered gabbro with natural bottom seawater at 425 °C and 400 bar and at 425 and 475 °C at 1000 bar at variable w/r (mass) ratios ranging from 0.5-10 by using cold seal pressure vessels (CSPV). The run durations varied from 3-72 h. Reacted fluids were analysed for major and trace elements by ICP-OES and ICP-MS. In our experiments, ';atypical' REE fluid pattern similar to those of SP fluids were obtained at high w/r ratio (5 and 10) that might be characteristic for focused fluid-flow along e.g., detachment faults at slow-spreading MOR [6]. In contrast, more ';typical'-like REE pattern with elevated LREE and slightly positive Eu anomalies have been reproduced at low w/r ratio (0.5-1). Results of numerical simulations imply that strong positive Eu anomalies of fluids and altered gabbro from high temperature MOR hydrothermal systems can be created by intense rock leaching processes at high w/r ratio (5-10). This suggests that hydrothermal circulation through the ocean crust creates ';typical' REE fluid pattern with strong positive Eu anomalies if seawater reacts with gabbroic host rock that has been already leached in REE at high fluid fluxes. Simulations of the temporal chemical evolution of

  1. Multistage metasomatism in lithospheric mantle beneath V. Grib pipe (Arkhangelsk diamondiferous province, Russia): evidence from REE patterns in garnet xenocrysts.

    NASA Astrophysics Data System (ADS)

    Shchukina, Elena; Alexei, Agashev; Nikolai, Pokhilenko

    2015-04-01

    150 garnet xenocrysts from V. Grib kimberlite pipe were analyzed for major and trace elements compositions. 70 % of garnet belong to lherzolite field; 14 % - megacrysts and pyroxenites; 11 % - eclogites; 4 % - harzburgite; 1 % (1- wehrlite defined by Sobolev (1973). Harzburgite garnets: sinusoidal REE patterns Smn/Ern > 5 (5.2 - 19.8). low Y (0.5 - 3.9 ppm), Zr (1.1 - 44.6 ppm), Ti (54 - 1322 ppm). Wehrlite garnetd: close to sinusoidal REE patterns, Smn/Ern - 1.8. Megacrysts and pyroxenites garnets: normal REE patterns Smn/Ern < 1 (0.2 - 0.6), high TiO2 (0.9 - 1.3 wt %). Lherzolite garnets 70 % show four groups of REE patterns similar to peridotite xenoliths (Shchukina et al., 2013, 2015). 1-st contains MREE at С1 level, Sm/Ern - 0.03, La/Ybn - 0.002. increasing La -Yb range, low Y, Zr, Ti indicating residual nature. 2-nd: MREE at 2 - 13 chondrite units, Smn/Ern (0.16 - 0.98), La/Ybn - 0.001 - 0.040 and flat pattern from MREE to HREE. 3-rd -MREE at 5 - 14 chondrite units, Sm/Ern > 1 (1.05 - 4.81) La/Ybn - 0.010-0.051 increasing an hump at MREE decreasing to HREE. 4-th: sinusoidal REE, Sm/Ern 4.2 - 27.2. and harzburgite Y, Zr, Ti . Average Cr2O3 content increases from 2-nd to the 3-rd group (3.3 to 5.7 wt%) and 4th (7.9 wt %). Average Y/Zr decreases from 2-nd (0.6) to 3rd (0.2) and 4th group (0.08). REE and Y, Zr, Ti indicate the metasomatic origin of garnets of 2, 3. 4 groups. Modeling of TREfor equilibrated melts and fractional crystallization 2nd group close to Turyino field basalts and 3-rd - to Izmozero field picrites of Arkhangelsk diamondiferous province (ADP). Basing on geochemical data of garnet xenocrysts and garnets and clinopyroxenes in peridotites (Shchukina et al., 2013, 2015) we suppose at least 3 stage of high-temperature metasomatic enrichment. 1st stage - is enrichment of residual garnets (found only in peridotite garnets) in LREE by the influence of carbonatite melt close to the Mela field carbonatites of ADP. REE patterns in clinopyroxenes from

  2. Rare earth elements (REE) as natural and applied tracers in the catchment area of Gessental valley, former uranium mining area of Eastern Thuringia, Germany

    NASA Astrophysics Data System (ADS)

    Buechel, G.; Merten, D.; Geletneky, J. W.; Kothe, E.

    2003-04-01

    Between 1947 and 1990 about 113.000 t of uranium were excavated at the former uranium mining site of Ronneburg (Eastern Thuringia, Germany). The legacy consists of more than 200 million m^3 of metasedimentary rocks rich in organic matter, sulfides and heavy metals originally deposited in mining heaps at the surface. The metasedimentary rocks formed under anoxic conditions about a 400 Mio. years ago are now exposed to oxic conditions. The oxidation of markasite and pyrite results in the formation of H_2SO_4. The formation of acid mine drainage (AMD) leads to high concentrations of uranium, rare earth elements (REE) and other heavy metals in surface water, seepage water and groundwater. This mobilization is due to alteration enhanced by high microbial activity and low pH. The tolerance mechanisms towards heavy metal pollution of soil substrate and surface/groundwater has allowed the selection of microbes which have, e.g. specific transporter genes and which are associated to plants in symbiotic interactions like mycorrhiza. In order to follow the processes linking alteration of metasedimentary rocks to biological systems the use of tracers is needed. One group of such tracers occuring in high concentrations in the water phase at the Ronneburg mining site are the REE (La-Lu) which are featured by very similar chemical behaviour. They show smooth but continuous variations of their chemical behaviour as a function of atomic number. For seepage water of the waste rock dump Nordhalde - sampled over a period of two years - the shale normalized REE patterns show enrichment of heavy REE and only minor variations, although the concentration differs. At sampling points in the surface water and in groundwater rather similar REE patterns were observed. Thus, REE can be used as tracers to identify diffuse inflow of REE-rich acid mine drainage of the dumps into the creek and the sediments. The absolute concentrations of REE in the creek and in ground water are up to 1000 times

  3. How lithology and climate affect REE mobility and fractionation along a shale weathering transect of the Susquehanna Shale Hills Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    Ma, L.; Jin, L.; Dere, A. L.; White, T.; Mathur, R.; Brantley, S. L.

    2012-12-01

    Shale weathering is an important process in global elemental cycles. Accompanied by the transformation of bedrock into regolith, many elements including rare earth elements (REE) are mobilized primarily by chemical weathering in the Critical Zone. Then, REE are subsequently transported from the vadose zone to streams, with eventual deposition in the oceans. REE have been identified as crucial and strategic natural resources; and discovery of new REE deposits will be facilitated by understanding global REE cycles. At present, the mechanisms and environmental factors controlling release, transport, and deposition of REE - the sources and sinks - at Earth's surface remain unclear. Here, we present a systematic study of soils, stream sediments, stream waters, soil water and bedrock in six small watersheds that are developed on shale bedrock in the eastern USA to constrain the mobility and fractionation of REE during early stages of chemical weathering. The selected watersheds are part of the shale transect established by the Susquehanna Shale Hills Observatory (SSHO) and are well suited to investigate weathering on shales of different compositions or within different climate regimes but on the same shale unit. Our REE study from SSHO, a small gray shale watershed in central Pennsylvania, shows that up to 65% of the REE (relative to parent bedrock) is depleted in the acidic and organic-rich soils due to chemical leaching. Both weathering soil profiles and natural waters show a preferential removal of middle REE (MREE: Sm to Dy) relative to light REE (La to Nd) and heavy REE (Ho to Lu) during shale weathering, due to preferential release of MREE from a phosphate phase (rhabdophane). Strong positive Ce anomalies observed in the regolith and stream sediments point to the fractionation and preferential precipitation of Ce as compared to other REE, in the generally oxidizing conditions of the surface environments. One watershed developed on the Marcellus black shale in

  4. The distribution and composition of REE-bearing minerals in placers of the Atlantic and Gulf coastal plains, USA

    USGS Publications Warehouse

    Bern, Carleton; Shah, Anjana K.; Benzel, William M.; Lowers, Heather A.

    2016-01-01

    Rare earth element (REE) resources are currently of great interest because of their importance as raw materials for high-technology manufacturing. The REE-phosphates monazite (light REE enriched) and xenotime (heavy REE enriched) resist weathering and can accumulate in placer deposits as part of the heavy mineral assemblage. The Atlantic and Gulf coastal plains of the southeastern United States are known to host heavy mineral deposits with economic concentrations of zircon, ilmenite and rutile. This study provides a perspective on the distribution and composition of REE phosphate minerals in the region. The elemental chemistry and mineralogy of sands and associated heavy-mineral assemblages from new and archived sediment samples across the coastal plains are examined, along with phase-specific compositions of monazite, xenotime and zircon. Both monazite and xenotime are present across the coastal plains. The phase-specific compositions allow monazite content to be estimated using La as a geochemical proxy. Similarly, both Y and Yb are geochemical proxies for xenotime, but their additional presence in zircon and monazite require a correction to prevent overestimation of xenotime content. Applying this correction, maps of monazite and xenotime content across the coastal plains were generated using sample coverage from the National Geochemical Database (NGS) and National Uranium Resource Evaluation (NURE). The NGS and NURE approach of sampling stream sediments in small watersheds links samples to nearby lithologies. The results show an approximately 40 km-wide band of primarily Cretaceous, marine sediments bordering the Piedmont province from North Carolina to Alabama in which monazite and xenotime content are relatively high (up to 4.4 wt. % in < 150 μm bulk sediment). Strong correlations between concentrations of the two phases were found, with estimated monazite:xenotime ratios ranging approximately 6:1 to 12:1 depending upon the dataset analyzed. From a resource

  5. REE chemistry and Sm-Nd systematics of late Archean weathering profiles in the Fortescue Group, Western Australia

    NASA Technical Reports Server (NTRS)

    MacFarlane, A. W.; Danielson, A.; Holland, H. D.; Jacobsen, S. B.

    1994-01-01

    Two weathering profiles, each consisting of an upper, sericite-rich zone and a lower, chlorite-rich zone, are preserved between flows of the Mt. Roe Basalt in the Fortescue Group, Hamersley Basin, Western Australia. REE concentrations in samples from these two profiles, which originally developed ca 2,760 Ma, show large variations depending on stratigraphic position. LREE abundances and (La/Yb)N are greatest at depths of 3-6 m below the paleosurface of the Mt. Roe #1 profile and are somewhat lower in samples above this level. The LREEs reach concentrations 6-9 times greater than in the underlying basalt, and thus appear to have been mobilized downward in the paleosol and concentrated in its middle part. LREE concentrations in the #2 profile show a similar distribution but with a sharp increase in all REE concentrations within 50 cm of the paleosurface. The distinction between the REE profiles in the two paleosols may be related to the difference in the overlying material. The #1 paleosol is overlain by a few meters of sediments and then by basalt, whereas the #2 paleosol is directly overlain by basalt. The LREEs appear to have been mobilized both during chemical weathering of the parental basalt and during later lower-greenschist-facies metamorphism and metasomatism of the paleosols. Remobilization of the REEs during the regional metamorphism of the Fortescue Group is confirmed by a whole-rock Sm-Nd reference isochron of Mt. Roe #1 samples with an age of 2,151 +/- 360 Ma. Variable initial 143Nd/144Nd values of unweathered basalt samples which may represent the paleosol protolith prevents a confident determination of the magnitude of LREE mobility. Both the initial mobilization of the REEs during weathering and the metasomatic remobilization appear to have taken place under redox conditions where Ce was present dominantly as Ce3+, because Ce anomalies are not developed within the sericite zone samples regardless of concentration. Europium anomalies in the

  6. REE chemistry and Sm-Nd systematics of late Archean weathering profiles in the Fortescue Group, Western Australia.

    PubMed

    MacFarlane, A W; Danielson, A; Holland, H D; Jacobsen, S B

    1994-04-01

    Two weathering profiles, each consisting of an upper, sericite-rich zone and a lower, chlorite-rich zone, are preserved between flows of the Mt. Roe Basalt in the Fortescue Group, Hamersley Basin, Western Australia. REE concentrations in samples from these two profiles, which originally developed ca 2,760 Ma, show large variations depending on stratigraphic position. LREE abundances and (La/Yb)N are greatest at depths of 3-6 m below the paleosurface of the Mt. Roe #1 profile and are somewhat lower in samples above this level. The LREEs reach concentrations 6-9 times greater than in the underlying basalt, and thus appear to have been mobilized downward in the paleosol and concentrated in its middle part. LREE concentrations in the #2 profile show a similar distribution but with a sharp increase in all REE concentrations within 50 cm of the paleosurface. The distinction between the REE profiles in the two paleosols may be related to the difference in the overlying material. The #1 paleosol is overlain by a few meters of sediments and then by basalt, whereas the #2 paleosol is directly overlain by basalt. The LREEs appear to have been mobilized both during chemical weathering of the parental basalt and during later lower-greenschist-facies metamorphism and metasomatism of the paleosols. Remobilization of the REEs during the regional metamorphism of the Fortescue Group is confirmed by a whole-rock Sm-Nd reference isochron of Mt. Roe #1 samples with an age of 2,151 +/- 360 Ma. Variable initial 143Nd/144Nd values of unweathered basalt samples which may represent the paleosol protolith prevents a confident determination of the magnitude of LREE mobility. Both the initial mobilization of the REEs during weathering and the metasomatic remobilization appear to have taken place under redox conditions where Ce was present dominantly as Ce3+, because Ce anomalies are not developed within the sericite zone samples regardless of concentration. Europium anomalies in the

  7. Determination of rare earth elements (REES) in airborne particulate matter (APM) collected in Tokyo, Japan, and a positive anomaly of europium and terbium.

    PubMed

    Suzuki, Yoshinari; Suzuki, Tatsunosuke; Furuta, Naoki

    2010-01-01

    The determination of rare earth elements (REEs) in airborne particulate matter (APM) was conducted, and the distribution pattern of atmospheric REEs was evaluated in this study. The APM was collected in the center of Tokyo, Japan, where serious air pollution is always of concern. A cellulose acetate membrane filter was used to collect the APM because Ba and REEs contamination is lower than that in a quartz glass fiber filter. The REEs measurement was conducted by ICP-MS after the digestion of the APM by a microwave acid digestion procedure. The standard reference material (SRM) of NIST 1648 urban particulate matter was used to validate the accuracy of the analytical method. The analytical results for SRM well agreed with those of the reference and reported values. Consequently, the analytical method established in this study was applied to the determination of REEs in APM collected in Tokyo, Japan. The obtained REEs distribution pattern in the APM showed a positive anomaly of Tb and Eu. The La/Sm ratio, which is considered to be as a good indicator of the anthropogenic effect, in size-classified APM showed a high degree of the anthropogenic effect in fine APM with a diameter of <1.1 µm. Emission sources of Tb, Eu and other REEs are discussed.

  8. Synthetic and natural Nakhla pyroxenes: Parent melt composition and REE partition coefficients

    NASA Technical Reports Server (NTRS)

    Mckay, G.; Le, L.; Wagstaff, J.

    1994-01-01

    Nakhla is one of the SNC meteorites, generally believed to be of martian origin. It is composed mainly of cumulus augite, in which primary igneous zoning is apparently preserved, and which serves as a recorder of the composition of Nakhla's parent melt and the conditions under which it crystallized. Knowledge of the composition and petrogenesis of this parent melt may help unravel Nakhla's relationship to the other SNC's, and provide clues to martian petrogenesis in general. This abstract reports new results of an ongoing study in which we are (1) comparing the major and minor element compositions of synthetic pyroxenes crystallized from various proposed parent melt compositions with those in Nakhla pyroxene to constrain the composition of the parent melt, and (2) measuring minor and trace element partition coefficients, particularly those of the REE, in order to obtain the most applicable D values with which to invert the natural pyroxene compositions to obtain the trace element composition of the parent melt. Results suggest that recent estimates of Nakhla's parent melt composition are too aluminous, and that mafic or ultramafic melts are more likely candidates.

  9. Partition coefficients of Hf, Zr, and REE between phenocrysts and groundmasses

    NASA Technical Reports Server (NTRS)

    Fujimaki, H.; Tatsumoto, M.; Aoki, K.-I.

    1984-01-01

    Partition coefficients of Hf, Zr, and REE between olivine, orthopyroxene, clinopyroxene, plagioclase, garnet, amphibole, ilmenite, phlogopite, and liquid are presented. Samples consist of megacrysts in kimberlite, phenocrysts in alkaline basalts, tholeiitic basalts and andesitic to dacitic rocks, and synthetic garnet and clinopyroxene in Hawaiian tholeiites. The Hf-Lu and Zr-Lu elemental fractionations are as large as the Lu-Sm or Lu-Nd fractionation. The Hf and Zr partition coefficients between mafic phenocrysts and liquids are smaller than the Lu partition coefficients, but are similar to the Nd or Sm partition coefficients. The Hf and Zr partition coefficients between ilmenite, phlogopite, and liquid are larger than the Lu partition coefficients for these minerals and their corresponding liquids. The Hf-Zr elemental fractionation does not occur except for extreme fractionation involving Zr-minerals and extremely low fO2. These data have an important bearing on chronological and petrogenetic tracer studies involving the Lu-Hf isotopic system.

  10. Recombinant cancer vaccines and new vaccine targets. Interview by Jenaid Rees.

    PubMed

    Schlom, Jeffrey

    2013-10-01

    Interview by Jenaid Rees, Commissioning Editor Jeffrey Schlom obtained his PhD from Rutgers University (NJ, USA). After obtaining his PhD, he worked at Columbia University (NY, USA) before moving in 1973 to the National Cancer Institute, National Institutes of Health (MD, USA). Since then he has served as the Chief of several sections, including his present position as the Chief of the Laboratory of Tumor Immunology and Biology in the Center for Cancer Research which he has held for the past 30 years. During this period, he has worked as an Adjunct Professor at George Washington University (Washington, DC, USA), served on the Editorial Board of several journals and holds membership in a number of committees. He holds over 30 patents and patent applications in the areas of vaccines, tumor antigens and monoclonal antibodies and has received honors and awards throughout his career. Jeffrey Schlom has been involved in translational research involving the immunotherapy of a range of carcinomas and predominantly works in the areas of tumor immunology, mechanisms of tumor cell-immune cell interactions and immune mechanisms. He has recently been working on the design and characterization of recombinant vaccines for cancer therapy.

  11. Sorption of REE and TPE on sulfonated strong-acid cation exchanger KU-2 from multicomponent HNO{sub 3} solutions

    SciTech Connect

    Chuveleva, E.A.; Kharitonov, O.V.; Firsova, L.A.

    1995-05-01

    Sorption of rare earths (REE) from multicomponent systems is studied as a function of solution acidity (0.1-2.0 M) and temperature (20-70{degrees}C). The elution curves for REE and transplutonium-element (TPE) sorption pass through a maximum, the value of which increases with decreasing solution acidity. The selectivity order changes for Y. This phenomenon is explained. The separation coefficients Nd-M are determined for various [HNO{sub 3}]. In the range [H{sup +}] = 0.5-2.01 M, the separation coefficients become <1. The optimal conditions for REE and TPE sorption are determined.

  12. Origin of REE-rich ferrocarbonatites in southern Siberia (Russia): implications based on melt and fluid inclusions

    NASA Astrophysics Data System (ADS)

    Prokopyev, Ilya R.; Borisenko, Alexander S.; Borovikov, Andrey A.; Pavlova, Galina G.

    2016-12-01

    Fe-rich carbonatites with a mineral assemblage of ankerite-calcite or siderite are widespread in southern Siberia, Russia. The siderite carbonatites are associated with F-Ba-Sr-REE mineralization and have a 40Ar/39Ar age of 117.2 ± 1.3 Ma. Melt and fluid inclusions suggest that the carbonatites formed from volatile-rich alkali- and chloride-bearing carbonate melts. Ankerite-calcite carbonatites formed from carbonatite melt at a temperature of more than 790 °C. The ferrocarbonatites (the second phase of carbonatite intrusion) formed from a sulfate-carbonate-chloride fluid phase (brine-melt) at >650 °C and ≥360 MPa. The brine-melt fluid phase had high concentrations of Fe and LREEs. A subsequent hydrothermal overprint contributed to the formation of economically important barite-Sr-fluorite-REE mineralization in polymict siderite breccia.

  13. Geochemistry of banded iron formation (BIF) host rocks, Yishui county, North China : major element, REE and other trace element analyses

    NASA Astrophysics Data System (ADS)

    Moon, I.; Lee, I.; Yang, X.

    2013-12-01

    Banded iron formation (BIF) in Yishui area, Western Shangdong Province in North China was formed from late Archean to early Paleoproterizoic (2.6Ga-2.5Ga). Amphibolite, metasediment (schist, gneiss) and migmatitic granite consist of host rocks of the BIF in North China. To find characteristics of BIF host rocks, major element, rare earth element and trace element analyses of whole rocks were conducted. Major elements are analyzed using X-ray Fluorescene Spectrometer (XRF) and REE and trace elements are analyzed by Inductively Coupled Plazma Mass Spectrometer (ICP-MS). Amphibolites show large negative Eu anomalies ([Eu]/[Eu*]=0.91~0.99) and ranges of REE are ∑REE=305~380 ppm. LREE/HREE ratios are (La/Lu)cn=21.07~26.12. SiO2 contents are 35.1~44.2 wt% and some samples have high Loss On Ignition values ([LOI]=8.35-10.06 wt%) compared to other amphibolites. LOI value is related to water and volatile contents in the rocks and it reflects amphibolite got high degree of alteration. The Fe and Mg mobility effects are shown by Fe2O3/MgO ratios which are 4.7~5.7. The Mg# varies from 25.6 to 29.3. Migmatitic granites have various range of ∑REE=21~241 ppm. They show both Eu negative anomalies ([Eu]/[Eu*]=0.53~0.71) and positive Eu anomalies ([Eu]/[Eu*]=1.95). Migmatitic granites have high SiO2 contents (68.8~72.2 wt%) and Al2O3 (13.4~14.2 wt%) contents. They have relatively low TiO2 (<0.5 wt%), MgO ( <0.6 wt%) and P2O5 (<0.2 wt%) contents. Gneiss samples were collected either from core or from mine pit. Core samples have negative Eu anomalies ([Eu]/[Eu*]=0.27~0.62) and show enriched LREE than HREE ((La/Lu)cn=45.60~62.32). Mine pit samples have positive Eu anomalies ([Eu]/[Eu*]=1.64~2.87) and almost flatten pattern except Eu anomalies ((La/Lu)cn=2.19~2.37). Core samples have higher Al2O3, TiO2, Na2O and K2O contents than mine pit samples. But remarkably mine pit samples have high contents of Fe2O3 (>40.4 wt%). Schists are divided into two types following REE patterns. Some

  14. Audre's daughter: Black lesbian steganography in Dee Rees' Pariah and Audre Lorde's Zami: A New Spelling of My Name.

    PubMed

    Kang, Nancy

    2016-01-01

    This article argues that African-American director Dee Rees' critically acclaimed debut Pariah (2011) is a rewriting of lesbian poet-activist Audre Lorde's iconic "bio-mythography" Zami: A New Spelling of My Name (1982). The article examines how Rees' work creatively and subtly re-envisions Lorde's Zami by way of deeply rooted and often cleverly camouflaged patterns, resonances, and contrasts. Shared topics include naming, mother-daughter bonds, the role of clothing in identity formation, domestic abuse, queer time, and lesbian, gay, bisexual, and transgender legacy discourse construction. What emerges between the visual and written texts is a hidden language of connection--what may be termed Black lesbian steganography--which proves thought-provoking to viewers and readers alike.

  15. Tectonic implications of REE, Th, and Sc analyses of metamorphosed mudstones, Boyden Cave roof pendant, Sierra Nevada, California

    SciTech Connect

    Hanson, A.D.; Girty, G.H. . Dept. of Geological Sciences)

    1993-04-01

    The Boyden Cave pendant is subdivided into an eastern sequence, chaotic unit, and western sequence. The western sequence has an outcrop width of about 2.5 km and consists of a metasandstone unit, calcsilicate schist unit, andalusite biotite schist unit, and marble unit all metamorphosed to amphibolite grade. Because of complex structural relationships, the stratigraphic thicknesses of these four units are unknown. Psammites within the metasandstone unit, on average, are composed of 85.5 [+-] 4.2% quartz, 8.1 [+-] 4.6% total feldspar, 4.8 [+-] 2.8% white mica, 1.4 [+-] 1.3% biotite, and 0.1 [+-] 0.2% epidote (N = 17). The authors analyzed 10 mudstone samples for major, trace, and REEs from the metasandstone and andalusite biotite schist units of the Boyden Cave pendant. Chondrite-normalized REE distribution patterns exhibit LREE-enrichment trends, and Eu anomalies that vary from 0.61 to 0.86, and average 0.69. Such patterns are characteristic of mudstones composed of continentally derived detritus and are consistent with the complete absence of volcanic material. A similar set of geochemical data was collected from the proposed correlative miogeoclinal units in the Nopah Range, SE California. REE distribution patterns for mudstones from the Stirling Quartzite Wood Canyon Formation, and Carrara Formation exhibit LREE-enrichment trends and Eu anomalies that vary from 0.65 to 0.75, and average 0.68. REE distribution patterns for samples collected from the Boyden Cave and Nopah Range are nearly identical in all aspects. On a La-Th-Sc diagram, data from the mudstones in the Boyden Cave pendant cluster with data from the Nopah Range. Thus, the authors conclude that their data are consistent with the proposed correlations suggested by R.A. Schweickert and M.M. Lahren, and that the western sequence of the Boyden Cave pendant may represent a displaced fragment of the Cordilleran miogeocline.

  16. Fingerprinting young ignimbrites in Dominica (Lesser Antilles): Constraints from bulk REEs, apatite chemistry, and U-Th zircon chronology

    NASA Astrophysics Data System (ADS)

    Frey, H. M.; Manon, M. R.; Brehm, S.

    2015-12-01

    Multiple methods of fingerprinting tephra deposits enable distinction of separate magma batches beneath the island of Dominica. Previous studies have invoked a single large batholith but apatite REE chemistry is inconsistent with generation of multiple ignimbrites by fractional crystallization. The crystal-rich, andesite-dacite (58-66 wt% SiO2) ignimbrites comprise the largest explosive eruption in the Caribbean in the last 200 kyr, erupting a magma volume >58 km3 (Carey and Sigurdsson, 1980). Although the ignimbrites appear to emanate from several vents, their broad similarity in bulk chemistry, phase assemblage (pl + opx + cpx + hbl + ilm + mag + zrn + ap), and mineral composition, has led previous workers to suggest that Dominica is underlain by a single large batholith eruptions younging from north to south. However, bulk REE chemistry, solution ICP-MS chemistry of individual apatite grains, and ion microprobe U-Th dating of zircon rims from pumice clasts suggest a more complex plumbing system. More than 150 pumice clasts from northernmost (Morne aux Diables), northern (Wesley, Pointe Ronde, Grand Savanne), central (Layou, Roseau, Rosalie), and southern (Grand Bay, Grand Fonde) ignimbrites were analyzed for bulk chemistry. Geographically controlled differences exist in the concavity of the middle-heavy REE (Dy*). In central Dominica, apatites from the more evolved Layou Ignimbrite are depleted in middle REE compared to the nearby Roseau Ignimbrite, belying a genetic relationship via fractional crystallization. U-Th zircon rim ages in the northernmost and northern deposits were in secular equilibrium (>350 ka), whereas the central and southern ignimbrites yielded several populations of crystallization ages: Layou (99±12 ka), Roseau (139±12 ka; 65±17 ka), and Grand Bay (107±15 ka; 211±61 ka). Collectively, these observations are consistent with partial melting of magma batches prior to eruption rather than fractional crystallization of a single magma chamber.

  17. The impact of vegetation on REE fractionation in stream waters of a small forested catchment (the Strengbach case)

    NASA Astrophysics Data System (ADS)

    Stille, P.; Steinmann, M.; Pierret, M.-C.; Gauthier-Lafaye, F.; Chabaux, F.; Viville, D.; Pourcelot, L.; Matera, V.; Aouad, G.; Aubert, D.

    2006-07-01

    Previous studies on waters of a streamlet in the Vosges Mountains (Eastern France) have shown that strontium and rare earth elements (REE) mainly originate from preferential dissolution of apatite during weathering. However, stream water REE patterns normalized to apatite are still depleted in the light REE (LREE, La-Sm) pointing to the presence of an additional LREE depleting process. Vegetation samples are strongly enriched in LREE compared to stream water and their Sr and Nd isotopic compositions are comparable with those of apatite and stream water. Thus, the preferential LREE uptake by vegetation might lead to an additional LREE depletion of surface runoff in the forested catchment. Mass balance calculations indicate, that the yearly LREE uptake by vegetation is comparable with the LREE export by the streamlet and, therefore, might be an important factor controlling LREE depletion in river water. This is underlined by the observation that rivers from arctic and boreal regions with sparse vegetation appear to be less depleted in LREE than rivers from tropical environments or boreal environments with a dense vegetation cover.

  18. REE radiation fault model: a tool for organizing and communication radiation test data and construction COTS based spacebourne computing systems

    NASA Technical Reports Server (NTRS)

    Ferraro, R.; Some, R.

    2002-01-01

    The growth in data rates of instruments on future NASA spacecraft continues to outstrip the improvement in communications bandwidth and processing capabilities of radiation-hardened computers. Sophisticated autonomous operations strategies will further increase the processing workload. Given the reductions in spacecraft size and available power, standard radiation hardened computing systems alone will not be able to address the requirements of future missions. The REE project was intended to overcome this obstacle by developing a COTS- based supercomputer suitable for use as a science and autonomy data processor in most space environments. This development required a detailed knowledge of system behavior in the presence of Single Event Effect (SEE) induced faults so that mitigation strategies could be designed to recover system level reliability while maintaining the COTS throughput advantage. The REE project has developed a suite of tools and a methodology for predicting SEU induced transient fault rates in a range of natural space environments from ground-based radiation testing of component parts. In this paper we provide an overview of this methodology and tool set with a concentration on the radiation fault model and its use in the REE system development methodology. Using test data reported elsewhere in this and other conferences, we predict upset rates for a particular COTS single board computer configuration in several space environments.

  19. A study of REE and Pb, Sr and Nd isotopes in garnet-lherzolite xenoliths from Mingxi, Fujian Province

    USGS Publications Warehouse

    Wankang, H.; Junwen, W.; Basu, A.R.; Tatsumoto, M.

    1993-01-01

    The REE and Pb, Sr, Nd isotopes in three xenoliths from limburgite and scoria-breccias, including spinel-lherzolite, spinel-garnet-lherzolite and phlogopite-gamet-lherzolite, were analysed. The REE contents of the xenoliths are 1.3 to 3.3 times those of the chondrites with their REE patterns characterized by weak LREE depletion. The143Nd/144Nd values of whole rocks and minerals range from 0.51306 to 0.51345 with ??Nd=+ 8.2- +15.8,206Pb/204 Pb < 18.673, and207Pb/204Pb < 15.574. All this goes to show that the upper mantle in Mingxi at the depth of 67-82 km is a depleted mantle of MORB type, with87Sr/86 Sr ratios 0.70237-0.70390. In Nd-Sr diagram the data points of whole rocks are all out of the mantle array, implying that the xenoliths from Mingxi have more radiogenic Sr isotopes than those of the mantle array. ?? 1993 Institute of Geochemistry, Chinese Academy of Sciences.

  20. Direct determination of europium valence state by XANES in extraterrestrial merrillite: Implications for REE crystal chemistry and martian magmatism

    SciTech Connect

    Shearer, C.K.; Papike, J.J.; Burger, P.V.; Sutton, S.R.; McCubbin, F.M.; Newville, M.

    2012-03-15

    The relative proportion of divalent and trivalent Eu has proven to be a useful tool for estimating f{sub O{sub 2}} in various magmatic systems. However, in most cases, direct determination of the Eu valence state has not been made. In this study, direct determination of Eu valence by XANES and REE abundance in merrillite provide insights into the crystal chemistry of these phosphates and their ability to record conditions of magmatism. Merrillite strongly prefers Eu{sup 3+} to Eu{sup 2+}, with the average valence state of Eu ranging between 2.9 and 3 over approximately six orders of magnitude in f{sub O{sub 2}}. The dramatic shift in the REE patterns of merrillite in martian basaltic magmas, from highly LREE-depleted to LREE-enriched, parallels many other trace element and isotopic variations and reflects the sources for these magmas. The behavior of REE in the merrillite directly reflects the relationship between the eightfold-coordinated Ca1 site and adjacent sixfold Na and tetrahedral P sites that enables charge balancing through coupled substitutions.

  1. Oxygen Fugacity of the Martian Mantle From Pyroxene/Melt Partitioning of REE

    NASA Technical Reports Server (NTRS)

    Musselwhite, D. S.; Jones, J. H.

    2003-01-01

    This study is part of an ongoing effort to calibrate the pyroxene/melt REE oxybarometer for conditions relevant to the martian meteorites. Redox variations have been reported among the shergottites. Wadhwa used the Eu and Gd augite/melt partitioning experiments of McKay, designed for the LEW86010 angrite, to infer a range of fo2 for the shergottites. Others inferred fo2 using equilibria between Fe-Ti oxides. There is fairly good agreement between the Fe-Ti oxide determinations and the estimates from Eu anomalies in terms of which meteorites are more or less oxidized. The Eu anomaly technique and the Fe-Ti oxide technique both essentially show the same trend, with Shergotty and Zagami being the most oxidized and QUE94201 and DaG 476 being the most reduced. Thus, the variation in fo2 appears to be both real and substantive. However, although the redox trends indicated by the two techniques are similar, there is as much as two log unit offset between the results of three researchers. One explanation for this offset is that the Eu calibration used for the shergottites was actually designed for the LEW86010 angrite, a silica-undersaturated basalt whose pyroxene (diopside) compositions are rather extreme. To correct this, experiments have been conducted on the redox relationship of Eu partitioning relative to Sm and Gd for pyroxene/melt compositions more relevant to Martian meteorites. We report here preliminary results for experiments on pigeonite/melt partitioning as a function of fO2.

  2. On the estimation and detection of the Rees-Sciama effect

    NASA Astrophysics Data System (ADS)

    Fullana, M. J.; Arnau, J. V.; Thacker, R. J.; Couchman, H. M. P.; Sáez, D.

    2017-02-01

    Maps of the Rees-Sciama (RS) effect are simulated using the parallel N-body code, HYDRA, and a run-time ray-tracing procedure. A method designed for the analysis of small, square cosmic microwave background (CMB) maps is applied to our RS maps. Each of these techniques has been tested and successfully applied in previous papers. Within a range of angular scales, our estimate of the RS angular power spectrum due to variations in the peculiar gravitational potential on scales smaller than 42/h megaparsecs is shown to be robust. An exhaustive study of the redshifts and spatial scales relevant for the production of RS anisotropy is developed for the first time. Results from this study demonstrate that (i) to estimate the full integrated RS effect, the initial redshift for the calculations (integration) must be greater than 25, (ii) the effect produced by strongly non-linear structures is very small and peaks at angular scales close to 4.3 arcmin, and (iii) the RS anisotropy cannot be detected either directly-in temperature CMB maps-or by looking for cross-correlations between these maps and tracers of the dark matter distribution. To estimate the RS effect produced by scales larger than 42/h megaparsecs, where the density contrast is not strongly non-linear, high accuracy N-body simulations appear unnecessary. Simulations based on approximations such as the Zel'dovich approximation and adhesion prescriptions, for example, may be adequate. These results can be used to guide the design of future RS simulations.

  3. Tracing and tracking wastewater-derived substances in freshwater lakes and reservoirs: Anthropogenic gadolinium and geogenic REEs in Lake Paranoá, Brasilia

    NASA Astrophysics Data System (ADS)

    Merschel, Gila; Bau, Michael; Baldewein, Linda; Dantas, Elton Luiz; Walde, Detlef; Bühn, Bernhard

    2015-09-01

    Total and dissolved rare earth element (REEs) and U concentrations were determined for waters from Lake Paranoá (Brasilia, Brazil) sampled in the dry (November 2012) and wet seasons (July 2013). Shale-normalized REE patterns of all samples display the M-type lanthanide tetrad effect and large positive Gd anomalies, but only the total REE pool shows a positive Ce anomaly, possibly reflecting aeolian and/or fluvial input from surrounding laterites. The positive Gd anomaly increased strongly between 2012 and 2013. It reveals an anthropogenic dissolved Gd source that enters the lake with effluents from wastewater treatment plants, originating from the use of Gd-based contrast agents in magnetic resonance imaging. Because anthropogenic Gd is a tracer for other wastewater-derived substances, such as pharmaceuticals, REE geochemistry offers an inexpensive way to monitor the presence of wastewater-derived substances in the lake, which may be utilized as a drinking water reservoir in the near future.

  4. Partition coefficients for REE between garnets and liquids - Implications of non-Henry's Law behaviour for models of basalt origin and evolution

    NASA Technical Reports Server (NTRS)

    Harrison, W. J.

    1981-01-01

    An experimental investigation of Ce, Sm and Tm rare earth element (REE) partition coefficients between coexisting garnets (both natural and synthetic) and hydrous liquids shows that Henry's Law may not be obeyed over a range of REE concentrations of geological relevance. Systematic differences between the three REE and the two garnet compositions may be explained in terms of the differences between REE ionic radii and those of the dodecahedral site into which they substitute, substantiating the Harrison and Wood (1980) model of altervalent substitution. Model calculations demonstrate that significant variation can occur in the rare earth contents of melts produced from a garnet lherzolite, if Henry's Law partition coefficients do not apply for the garnet phase.

  5. The effect of the water-to-rock ratio on REE distribution in hydrothermal fluids: An experimental study

    NASA Astrophysics Data System (ADS)

    Beermann, Oliver; Garbe-Schönberg, Dieter; Holzheid, Astrid

    2013-04-01

    High-temperature submarine MOR hydrothermalism creates high elemental fluxes into, and out of, oceanic lithosphere significantly affecting ocean chemistry. The Turtle Pits hydrothermal system discovered at 5° S on the slow-spreading Mid-Atlantic Ridge (MAR) in water depths of ~3000 m (~300 bar) emanates 'ultrahot' fluids > 400 ° C [1] with high concentrations of dissolved gases (e.g., H2), transition metals, and rare earth elements (REE). The normalised REE patterns of these 'ultrahot' fluids are uncommon as they exhibit depletions of LREE and no Eu-anomaly ('special' REE-signature in [2]), which is in contrast to the "typical" LREE enrichment and pronounced positive Eu-anomaly known from many MOR vent fluids observed world-wide [e.g., 3]. Although hydrothermal fluid REE-signatures may play a key role in understanding processes during water-rock interaction, only few experimental data have been published on REE distribution in seawater-like fluids reacted with rocks from the ocean crust [e.g., 4, 5]. Besides temperature, the seawater-to-rock ratio (w/r ratio) strongly affects water-rock reaction processes and, thus, has significant control on the fluid chemistry [e.g., 6, 7]. To understand how vent fluid REE-signatures are generated during water-rock interaction processes we designed a series of experiments reacting different fluid types with mineral assemblages from fresh, unaltered gabbro at 425 ° C and 400 bar using cold seal pressure vessels (CSPV). Mixtures of 125-500 μm-sized hand-picked plagioclase and clinopyroxene grains separated from unaltered gabbro reacted in gold capsules with 3.2 wt.% NaCl(aq) fluid (similar to seawater salinity), or with natural seawater. The w/r (mass) ratio ranged from 1 to 100 and the run durations were varied from 3 to 30 d in the NaCl(aq) experiments, and was 3 d in the seawater experiments. The reacted fluids were extracted after quenching and analysed by ICP-OES and ICP-MS. Only in the seawater experiments, the gabbro

  6. Zr and REE mineralization in sodic lujavrite from the Saima alkaline complex, northeastern China: A mineralogical study and comparison with potassic rocks

    NASA Astrophysics Data System (ADS)

    Wu, Bin; Wang, Ru-Cheng; Yang, Jin-Hui; Wu, Fu-Yuan; Zhang, Wen-Lan; Gu, Xiang-Ping; Zhang, Ai-Cheng

    2016-10-01

    The Triassic Saima alkaline complex on the Liaodong Peninsula, northeastern China, consists mainly of potassic phonolite, nepheline syenite, and sodic lujavrite. The lujavrite shows significant Zr-REE mineralization, which is present in the form of early magmatic, Zr-REE-enriched clinopyroxene (30%-40%), titanite (5%), and loparite-(Ce), and late magmatic to hydrothermal wadeite, widespread eudialyte group minerals (5%-10%), and catapleiite. Ultimately, the fractionation of the alkaline magma leads to the crystallization of mosandrite and hezuolinite. Textural relations and compositional variation among the characteristic Zr-REE-bearing minerals record that both Zr and REEs were strongly incompatible in the sodic melt, but that Zr mineralization preceded REE mineralization. The main Zr-REE mineralization in the Saima lujavrite resulted from the high peralkalinity, Na/K ratio and HFSE content, low oxygen fugacity, and the intensive activity of water and volatiles of its evolving magma. The discontinuous and abrupt changes in melt composition and mineral assemblage from the potassic nepheline syenite of the complex to the sodic lujavrite suggest that their magma was derived from different episodes of magmatic activity with different physico-chemical characteristics, rather than from the continuous evolution of a single magmatic event.

  7. Evolution of the fluid in the REE-rich pegmatites of the Strange Lake pluton

    NASA Astrophysics Data System (ADS)

    Vasyukova, O.; Williams-Jones, A. E.

    2015-12-01

    Five types of aqueous inclusions are observed in the Mid-proterozoic peralkaline granites and pegmatites of the Strange Lake pluton (Québec-Labrador, Canada). From earliest to latest they are: primary aqueous inclusions associated with melt inclusions (type 1), with CH4 inclusions (types 2 a and b enriched in H2 and higher hydrocarbons respectively), and CO2 inclusions (type 3), primary aqueous inclusions, which show no apparent association with any gas-rich fluid (type 4) and secondary aqueous inclusions associated with mineral pseudomorphs (type 5). The salinity of the fluid decreases from the earliest type 1 (24.1 wt.% NaCl eq.) to type 2 a and b (21.2 and 14.2 wt.% NaCl eq. respectively), to type 3 (10.1 wt.% NaCl eq.) and type 4 inclusions (8.2 wt.% NaCl eq.). The salinity of type 5 inclusions is high, i.e., 16.6 wt.% NaCl eq.. The gas composition changes systematically from CH4 ± H2 in type 1 and 2a to CH4 + higher hydrocarbons in type 2b and to CO2 dominant type 3 inclusions. Most of the inclusions show re-equilibration texures ('implosion' halos). Another typical feature is a tendency to decrepitate at temperatures higher than 140-150 °C. The fluid evolution started with the exsolution of a saline aqueous liquid (~25 wt.% NaCl eq.) from the pegmatitic melt at a temperature of about 400 °C and a pressure around 1100 bars. Further evolution occurred due to cooling (isobaric) and oxidation of the fluid. Early initial oxidation led to formation of higher hydrocarbons by oxidative coupling of methane, and later, full-blown oxidation led to the production of CO2. The CO2 reacted with Na-rich fluid to form nahcolite, which caused a significant decrease in the apparent salinity down to a critical level, below which further oxidation led to an increase in the CO2/CH4 ratio and eventual disappearance of CH4. Isobaric cooling continued down to at least 150-170 °C, at which temperature the CO2 component was consumed to form REE-rich flurocarbonates. Nahcolite

  8. REE geochemistry of 3.2 Ga BIF from the Mapepe Formation, Barberton Greenstone Belt, South Africa

    NASA Astrophysics Data System (ADS)

    Yahagi, T. R.; Yamaguchi, K. E.; Haraguchi, S.; Sano, R.; Teraji, S.; Kiyokawa, S.; Ikehara, M.; Ito, T.

    2012-12-01

    Banded iron formations (BIFs) are chemical sediments interbedded with Fe- and Si-rich layers, characteristically present in the early history of the Earth. A popular hypothesis for the formation of BIFs postulates that dissolved oxygen produced by photosynthesizers such as cyanobacteria oxidized dissolved ferrous Fe supplied by submarine hydrothermal activities. During precipitation of Fe-oxide minerals, phosphorus and rare earth elements (REEs) were most likely adsorbed on their surface. Therefore, chemical compositions of REEs that adsorbed onto Fe-oxide have useful information on the seawater chemistry at the time of deposition. Especially, information on the redox state of seawater and the extent of the contribution of hydrothermal activity during BIF deposition are expected to have been recorded. Occurrence of BIF has been traditionally tied to the chemical evolution of the atmosphere. Rise of atmospheric oxygen, or as known as GOE (Great Oxidation Event: e.g., Holland, 1994), has been widely believed to have occurred at around 2.4 Ga ago. Contrary, however, some studies have suggested that such oxygenation could have occurred much earlier (e.g., Hoashi et al., 2009). In this study, we used 3.2 Ga old BIF from the Mapepe Formation at the bottom of the Fig Tree Group of the Swaziland Supergroup in the northeastern part of the Barberton Greenstone Belt, South Africa. We aimed to constrain the marine environment, and by inference atmospheric environment, at the time of BIF deposition from REE geochemistry. Major elements and REE compositions of 37 samples were measured using XRF and ICP-MS, respectively. Samples with less than 1.0 wt% Al2O3 are considered to be "pure" BIFs with minimal amount of continental contamination, and are expected to have inherited marine REE signatures. Abundance of REE normalized by C1 chondrite for the analyzed samples commonly exhibits positive Eu anomaly and LREE

  9. Genesis of the Bayan Obo Fe-REE-Nb deposit: Evidences from Pb-Pb age and microanalysis of the H8 Formation in Inner Mongolia, North China Craton

    NASA Astrophysics Data System (ADS)

    Lai, Xiaodong; Yang, Xiaoyong; Liu, Yulong; Yan, Zhiqiang

    2016-04-01

    The Bayan Obo Fe-REE-Nb deposit is a world-largest REE deposit in Inner Mongolia, North China Craton. It also contains large Fe and Nb reserves. The REE ore body is hosted in H8 dolomite of the Bayan Obo Group. Depositional time and genesis of H8 dolomite are still controversial in addressing the genesis of the REE deposit. In this study, Pb-Pb age and geochemical features of carbonate minerals in H8 dolomite have been studied, providing constraints to genesis of H8 dolomite and the REE deposit. Results of Pb-Pb dating from unmetamorphosed and non-mineralized domains of the H8 dolomite well constrain the depositional age as 1619 ± 150 Ma, which is earlier than both REE ore and carbonatite dykes in the Bayan Obo region. This indicates that REE mineralization has characteristics of epigenetic origin. Geochemical data of carbonate minerals in H8 dolomite have low REE contents, distinctly distinguished from those carbonatitic dykes. However, the fine-grained H8 dolomite whole rocks have high REE contents, similar to those carbonatitic dykes. Mineral analysis suggests a close relationship between REE mineralization and calcite carbonatite dykes and related-derived fluids, which could transport a large amounts of REE. Integrated with these new geochronological and geochemical data, we draw conclusion that the Bayan Obo Group was a Proterozoic depositional succession, REE mineralization is as result of sedimentary carbonate rocks once being metasomatised by fluids derived from regional REE-rich calcite carbonatitic magma at depth.

  10. Donnan membrane speciation of Al, Fe, trace metals and REEs in coastal lowland acid sulfate soil-impacted drainage waters.

    PubMed

    Jones, Adele M; Xue, Youjia; Kinsela, Andrew S; Wilcken, Klaus M; Collins, Richard N

    2016-03-15

    Donnan dialysis has been applied to forty filtered drainage waters collected from five coastal lowland acid sulfate soil (CLASS) catchments across north-eastern NSW, Australia. Despite having average pH values<3.9, 78 and 58% of Al and total Fe, respectively, were present as neutral or negatively-charged species. Complementary isotope dilution experiments with (55)Fe and (26)Al demonstrated that only soluble (i.e. no colloidal) species were present. Trivalent rare earth elements (REEs) were also mainly present (>70%) as negatively-charged complexes. In contrast, the speciation of the divalent trace metals Co, Mn, Ni and Zn was dominated by positively-charged complexes and was strongly correlated with the alkaline earth metals Ca and Mg. Thermodynamic equilibrium speciation calculations indicated that natural organic matter (NOM) complexes dominated Fe(III) speciation in agreement with that obtained by Donnan dialysis. In the case of Fe(II), however, the free cation was predicted to dominate under thermodynamic equilibrium, whilst our results indicated that Fe(II) was mainly present as neutral or negatively-charged complexes (most likely with sulfate). For all other divalent metals thermodynamic equilibrium speciation calculations agreed well with the Donnan dialysis results. The proportion of Al and REEs predicted to be negatively-charged was also grossly underestimated, relative to the experimental results, highlighting possible inaccuracies in the stability constants developed for these trivalent Me(SO4)2(-) and/or Me-NOM complexes and difficulties in modeling complex environmental samples. These results will help improve metal mobility and toxicity models developed for CLASS-affected environments, and also demonstrate that Australian CLASS environments can discharge REEs at concentrations an order of magnitude greater than previously reported.

  11. Variations in the neodymium and strontium isotopic composition and REE content of molluscan shells from the Cretaceous Western Interior seaway

    SciTech Connect

    Whittaker, S.G.; Kyser, T.K. )

    1993-08-01

    Rare earth element concentrations, [epsilon][sub ND](T) values, and strontium isotopic compositions of mollusc shells were used to trace variations in the neodymium and strontium isotopic composition of the epicontinental Late Cretaceous Western Interior seaway of North America. Rare earth element patterns are different in aragonite and calcite produced by the molluscs endemic to the seaway, indicating that either mineralogical control or possibly scavenging by organic films associated with the different phases of biogenic carbonate resulted in differential partitioning of the REEs from seawater during shell formation. The biogenic carbonate also may contain REEs associated with Fe-flocs trapped in the shells during growth, but these flocs cannot result in different REE patterns of aragonite and calcite produced by the molluscs. The neodymium isotopic composition of the Western Interior seaway is inferred to have varied 13 [epsilon]-units over 20 My as a result of incursions of seawater from the Arctic Ocean and Gulf of Mexico, river influx from tectonically active terranes, benthic diagenetic fluxes, and volcanic ash falls. Ash from a variety of volcanic centers in western North America was significant in producing rapid and marked changes in [sup 143]Nd/[sup 144]Nd ratios of the seaway, and abrupt regional variations in neodymium isotopic composition of the seaway make the construction of an accurate neodymium isotope evolution curve difficult for this basin. Strontium isotopic compositions of the mollusc shells indicate the [sup 87]Sr/[sup 86]Sr ratio of the Western Interior seaway was generally similar to contemporaneous oceans, although, periodically, the basin had strontium isotopic compositions distinct from contemporaneous seawater. 58 refs., 7 figs., 3 tabs.

  12. REE and Lu-Hf systematics of zircons from rapakivi granites and associated rocks of supercontinent Nuna (Columbia)

    NASA Astrophysics Data System (ADS)

    Ronkin, Yu. L.; Gerdes, A.; Maslov, A. V.

    2015-03-01

    The last of the rifting events at 1.37-1.45 Ga that is considered to have led to the final breakup of Nuna was recorded in most of its building blocks (Laurentia, Baltica, and Siberian craton). At the type locality for the Riphean on the western slope of the South Urals, this event was recognized as the Mashak igneous event (˜1380 Ma) and can be classified as a LIP based on the volumes of magma generated (total igneous volumes >0.05 × 106 km3). The emplacement of large volumes of A-type granitic plutons in Laurentia and northwestern Baltica (in the present coordinates) was almost synchronous with this event. In the South Urals, within the Bashkirian meganticlinorium, the processes of granite generation and emplacement during this time took place on a much smaller scale. Anorogenic granites of this region are represented by rapakivi granites of the Berdyaush massif. The first REE and Lu-Hf isotope data for zircons from rapakivi granites and associated rocks of the Berdyaush massif reveal almost identical Lu-Hf isotope ages (˜1383 Ma) of rapakivi granites, quartz syenitic diorites, and nepheline syenites. It was shown that these rocks, which were emplaced into the heterogeneous Proterozoic crust between the Early and Middle Riphean, have the Hf isotopic compositions and Lu-Hf model ages reflecting the contribution from crustal sources with ages of 2013-2219 Ma, whereas the associated gabbros indicate derivation from a source with the Lu-Hf ages of 1658 ± 1685 Ma and moderately depleted ɛHf(1383) of (4.1 ± 0.7-4.9 ± 0.6). The REE characteristics (ΣREE, Eu/Eu*, Ce/Ce*, Pr/Pr*, La/Lu) and Lu-Hf isotope systematics of zircons can be used to constrain the history and genetic evolution of supercontinents, e.g., supercontinent Nuna (Columbia) in particular.

  13. The distribution of anthropogenic REE in the Dutch distributaries of the Rhine: the role of suspended matter

    NASA Astrophysics Data System (ADS)

    Roskam, Gerlinde; Verheul, Marc; Klaver, Gerard; Bakker, Ingrid

    2014-05-01

    In nature rare earth elements (REE) occur in fixed ratios; contamination with a single rare earth element causes a clear deviation from the natural NASC normalized REE-patterns: an anomaly. REE are progressively used in many high technology products and processes. For example, gadolinium-containing chelates have been used since the '80s as contrasting agent in MRI-imaging. The pertaining anomaly is currently used as a tracer for distinguishing waste water from water unaffected by anthropogenic contamination. In the Dutch monitoring program in the Rhine-Meuse distributaries, total (10% HNO3 digested) and dissolved (< 0.45 µm) fractions in surface water are routinely analysed, and with two-week intervals suspended matter samples are collected with a centrifuge. Since 2008, the set of analysed elements was extended with REE, enabling this study. Lobith, the entry point of the River Rhine in The Netherlands, shows an annual oscillation in the magnitude of the lanthanum (La) anomaly. This positive La-anomaly was reported by Kulaksiz and Bau in 2011; they identified the point source as a production plant for catalysts used in petroleum refining in the German city of Worms. Since the spring of 2011, samarium (Sm) is used in the same process, resulting in matching La- and Sm-anomalies. The anthropogenic La and Sm concentrations are predominantly present in the total fraction, which suggests that the anthropogenic La and Sm concentrations are associated with suspended matter. The anthropogenic La and Sm concentrations are lower in the suspended matter samples collected with the centrifuge, suggesting a bias of these La and Sm concentrations in the finer fraction of the suspended matter. The anthropogenic La en Sm concentrations remain relatively constant throughout the rivers, but close to Lake IJsselmeer and the North Sea, sedimentation causes a sharp decrease in the anthropogenic concentrations. Detailed sampling of sediments, suspended matter and water could give a

  14. Stability constants for mono- and dioxalato-complexes of Y and the REE, potentially important species in groundwaters and surface freshwaters

    NASA Astrophysics Data System (ADS)

    Schijf, J.; Byrne, R. H.

    2001-04-01

    We present the first measured set of stability constants for mono- and dioxalato-complexes of yttrium and all rare earths except Pm (Y+REE), Oxβ n = [MOx n3-2n] [M 3+] -1 [Ox 2-] -n(where [ ] ≡ concentrations, M ≡ Y+REE, and Ox 2- ≡ C 2O 42-). Aqueous solutions of Y+REE were titrated with oxalic acid in the presence of a cation-exchange resin, and Y+REE concentrations in the solution phase were measured by ICP-MS. This method allows investigation of all Y+REE simultaneously under identical conditions and is thus very sensitive to subtle inter-element variations in log Oxβ n. Experiments were performed at a single ionic strength ( I = 0.05 M), but at two values of pH. Patterns of log Oxβ 1 and log Oxβ 2, determined from our experiments, are similar in shape and reminiscent of those for carbonato-complexes. The average ratio of stepwise stability constants K 2/K 1 = Oxβ 2/( Oxβ 1) 2 is 0.05 ± 0.02 for Y+REE excluding La and Ce. Literature values of Oxβ 1(Eu) for 0.03 mol/L ≤ I ≤ 1 mol/L were used to derive the relation log Oxβ 1(Eu) = log Oxβ 10(Eu) - 6.132√ I/(1 + 1.47√ I) + 0.902 I, where log Oxβ 10(Eu) is the stability constant at infinite dilution. Applying this relation to all Y+REE, the following values of log Oxβ 10 (at zero ionic strength) were found: 6.66 (Y), 5.87 (La), 5.97 (Ce), 6.25 (Pr), 6.31 (Nd), 6.43 (Sm), 6.52 (Eu), 6.53 (Gd), 6.63 (Tb), 6.74 (Dy), 6.77 (Ho), 6.83 (Er), 6.89 (Tm), 6.95 (Yb), 6.96 (Lu). These values, which are based on direct measurements for each individual Y+REE, agree quite well with published extrapolations that are mostly based on linear free-energy relationships. Total oxalate concentrations of 10 -5-10 -3 M have been reported for soil solutions. Free oxalate ions persist at much lower pH than free carbonate ions and a simple speciation model demonstrates that oxalato-complexes can dominate Y+REE speciation in mildly acidic groundwaters of low-to-moderate alkalinity.

  15. Experimental study of REE, Ba, Sr, Mo and W partitioning between carbonatitic melt and aqueous fluid with implications for rare metal mineralization

    NASA Astrophysics Data System (ADS)

    Song, WenLei; Xu, Cheng; Veksler, Ilya V.; Kynicky, Jindrich

    2016-01-01

    Carbonatites host some unique ore deposits, especially rare earth elements (REE). Hydrothermal fluids have been proposed to play a significant role in the concentration and transport of REE and other rare metals in carbonatites, but experimental constraints on fluid-melt equilibria in carbonatitic systems are sparse. Here we present an experimental study of trace element (REE, Ba, Sr, Mo and W) partitioning between hydrous fluids and carbonatitic melts, bearing on potential hydrothermal activity associated with carbonatite ore-forming systems. The experiments were performed on mixtures of synthetic carbonate melts and aqueous fluids at 700-800 °C and 100-200 MPa using rapid-quench cold-seal pressure vessels and double-capsule assemblages with diamond traps for analyzing fluid precipitates in the outer capsule. Starting mixtures were composed of Ca, Mg and Na carbonates spiked with trace elements. Small amounts of F or Cl were added to some of the mixtures to study the effects of halogens on the element distribution. The results show that REE, Ba, Sr, Mo and W all preferentially partition into carbonatite melt and have fluid-melt distribution coefficients ( D f/m) below unity. The REE partitioning is slightly dependent on the major element (Ca, Mg and Na) composition of the starting mixtures, and it is influenced by temperature, pressure, and the presence of halogens. The fluid-melt D values of individual REE vary from 0.02 to 0.15 with D_{Lu}^{f} / {fm}{m} being larger than D_{La}^{f} / {fm}{m} by a factor of 1.1-2. The halogens F and Cl have strong and opposite effects on the REE partitioning. Fluid-melt D REE are about three times higher in F-bearing compositions and ten times lower in Cl-bearing compositions than in halogen-free systems. D_{W}^{f} / {fm}{m} and D_{Mo}^{f} / {fm}{m} are the highest among the studied elements and vary between 0.6 and 0.7; D_{Ba}^{f} / {fm}{m} is between 0.05 and 0.09, whereas D_{Sr}^{f} / {fm}{m} is at about 0.01-0.02. The

  16. Trace elements and REE geochemistry of Middle Devonian carbonate mounds (Maïder Basin, Eastern Anti-Atlas, Morocco): Implications for early diagenetic processes

    NASA Astrophysics Data System (ADS)

    Franchi, Fulvio; Turetta, Clara; Cavalazzi, Barbara; Corami, Fabiana; Barbieri, Roberto

    2016-08-01

    Trace and rare earth elements (REEs) have proven their utility as tools for assessing the genesis and early diagenesis of widespread geological bodies such as carbonate mounds, whose genetic processes are not yet fully understood. Carbonates from the Middle Devonian conical mud mounds of the Maïder Basin (eastern Anti-Atlas, Morocco) have been analysed for their REE and trace element distribution. Collectively, the carbonates from the Maïder Basin mud mounds appear to display coherent REE patterns. Three different geochemical patterns, possibly related with three different diagenetic events, include: i) dyke fills with a normal marine REE pattern probably precipitated in equilibrium with seawater, ii) mound micrite with a particular enrichment of overall REE contents and variable Ce anomaly probably related to variation of pH, increase of alkalinity or dissolution/remineralization of organic matter during early diagenesis, and iii) haematite-rich vein fills precipitated from venting fluids of probable hydrothermal origin. Our results reinforce the hypothesis that these mounds were probably affected by an early diagenesis induced by microbial activity and triggered by abundance of dispersed organic matter, whilst venting may have affected the mounds during a later diagenetic phase.

  17. New data on REE and rare-metal mineralization in pegmatites of the Slyudyanogorsk muscovite deposit in the Southern Urals

    NASA Astrophysics Data System (ADS)

    Popova, V. I.; Muftakhov, V. A.; Popov, V. A.; Blinov, I. A.; Kotlyarov, V. A.

    2016-12-01

    The Slyudyangorsk muscovite deposit in the southern Urals was explored and mined in 1926-1957. By the mid-1950s, 104 veins of quartz-feldspar pegmatites including 21 muscovite-bearing veins have been found. Pegmatites with giant black Y-bearing epidote crystals are crosscut by veins with giant muscovite crystals, which, in turn, are intersected by veins of two-mica-quartz-two-feldspar pegmatites with rare-metal and REE mineralization. Microprobe data on compositions of complex Ti-Ta-Nb oxides [fergusonite-(Y), samarskite-(Y), euxenite-(Y), polycrase-(Y), columbite-(Fe), pyrochlore supergroup] are characterized, as well as of uraninite, ilmenorutile, scheelite, Y-bearing epidote, certain sulfides and rock-forming minerals from the Slyudyanogorsk deposit. The morphology and interrelation of minerals indicate that they are the result of crystal growth in cavities rather than of metasomatic replacement of gneisses, as has been suggested earlier. Thus, it is more promising for rare-metal and REE minerals in the Slyudorudnik area to be found in igneous rocks (granitic muscovite-quartz-feldspar pegmatites with the Nb-Ta-Ti-Y-U-W-Mo mineralization) than in metasomatic rocks.

  18. Ion microprobe U-Th-Pb dating and REE analyses of phosphates in nakhlites: Lafayette and Yamato-000593/000749

    NASA Astrophysics Data System (ADS)

    Terada, Kentaro; Sano, Yuji

    2004-12-01

    U, Th, and Pb isotopes and rare earth elements (REEs) in individual phosphate grains from martian meteorites, Lafayette and Yamato-000593/000749, were measured using a sensitive high- resolution ion microprobe (SHRIMP). Observed U-Pb data of 12 apatite grains from Yamato-000593/ 000749 are well represented by linear regressions in both "conventional" 2D isochron plots and the 3D U-Pb plot (total Pb/U isochron), indicating that the formation age of this meteorite is 1.53 +/- 0.46 Ga (2?). However, the data of nine apatite grains from Lafayette are well represented by planar regression rather than linear regression, indicating that its formation age is 1.15 +/- 0.34 Ga (2?) and that a secondary alteration process slightly disturbed its U-Pb systematics as discussed in the literature regarding Nakhla. The observed REE abundance patterns of the apatites in Lafayette and Yamato-000749, normalized to CI chondrites, are characterized by a progressive depletion of HREEs, a negative Eu anomaly, similarity to each other, and consistency with previously reported data for Nakhla. Considering the extensive data from other radiometric systems such as Sm-Nd, Rb-Sr, Ar-Ar, and trace elements, our results suggest that the parent magmas of the nakhlites, including the newly found Yamato-000593/000749, are similar, and that their crystallization ages are ~1.3 Ga.

  19. Using Rare Earth Element (REE) tracers to identify preferential micro-sites of post-fire aeolian erosion

    NASA Astrophysics Data System (ADS)

    Van Pelt, R.; Zobeck, T. M.; Barnes, M. A.; Baddock, M.; D'Odorico, P.

    2011-12-01

    Plant communities in desert environments are spatially anisotropic. Nutrient islands develop below shrub canopies and in the bases of bunch grasses that enhance plant growth and reinforce the spatial anisotropy. Catastrophic disturbance that removes the vegetation such as fire or drought can result in the release of the trapped sediment which becomes redistributed over the landscape by wind and water. We applied Rare Earth Element (REE) tracers to different landscape positions of an anisotropic Northern Chihuahua Desert ecosystem at the Sevilleta National Wildlife Refuge in central New Mexico in an effort to study this process. We delineated three 0.5 m by 6 m plots of desert grassland and three plots of desert grassland-shrubland ecotone. Nitric acid was used to dissolve the REE oxides (Eu2O3, Dy2O3, and Pr6O11) which were then diluted in distilled water to a target concentration of 1 g REE l-1 and applied to the surface at a rate of 4 l m-2. From laboratory column studies using soil collected at the site, we estimated that this would penetrate the surface to a depth of 2.5 cm resulting in a sediment REE concentration of approximately 100 mg kg-1. Eu was applied to bare surfaces between vegetation characterized as sand with a surface covering of gravel, Pr was applied under grass clumps, and Dy was applied under Creosote Bush (Larrea tridentata (DC.). Two replicate 0.25 m2 areas of each surface type were also tagged to obtain a sample of tagged surface sediment for analysis. The area containing the plots was burned by U.S. Fish and Wildlife personnel on April 14, 2010. During the next two days, two grassland plots and two grassland-shrubland ecotone plots were tested by placing a portable boundary layer field wind tunnel over the plots and blowing them with 12 m s-1 wind for 10 minutes during which time a paired set of entrained sediment samples were captured at the outlet of the wind tunnel. This period was followed by a 30 minute test in which clean quartz sand

  20. Geochemical and Geochronologic Investigations of Zircon-hosted Melt Inclusions in Rhyolites from the Mesoproterozoic Pea Ridge IOA-REE Deposit, St. Francois Mountains, Missouri

    NASA Astrophysics Data System (ADS)

    Watts, K. E.; Mercer, C. N.; Vazquez, J. A.

    2014-12-01

    Silicic volcanic and plutonic rocks of an eroded Mesoproterozoic caldera complex were intruded and replaced by iron ore, and cross-cut by REE-enriched breccia pipes (~12% total REO) to form the Pea Ridge iron-oxide-apatite-REE (IOA-REE) deposit. Igneous activity, iron ore formation, and REE mineralization overlapped in space and time, however the source of REEs and other metals (Fe, Cu, Au) integral to these economically important deposits remains unclear. Melt inclusions (MI) hosted in refractory zircon phenocrysts are used to constrain magmatic components and processes in the formation of the Pea Ridge deposit. Homogenized (1.4 kbar, 1000°C, 1 hr) MI in zircons from rhyolites ~600 ft (PR-91) and ~1200 ft (PR-12) laterally from the ore body were analyzed for major elements by EPMA and volatiles and trace elements (H2O, S, F, Cl, REEs, Rb, Sr, Y, Zr, Nb, U, Th) by SHRIMP-RG. Metals (including Cu, Au) will be measured in an upcoming SHRIMP-RG session. U-Pb ages, Ti and REE were determined by SHRIMP-RG for a subset of zircon spots adjacent to MI (1458 ± 18 Ma (PR-12); 1480 ± 45 Ma (PR-91)). MI glasses range from fresh and homogeneous dacite-rhyolite (65-75 wt% SiO2) to heterogeneous, patchy mixtures of K-spar and quartz (PR-12, 91), and more rarely mica, albite and/or anorthoclase (PR-91). MI are commonly attached to monazite and xenotime, particularly along re-entrants and zircon rims (PR-91). Fresh dacite-rhyolite glasses (PR-12) have moderate H2O (~2-2.5 wt%), Rb/Sr ratios (~8) and U (~5-7 ppm), and negative (chondrite-normalized) Eu anomalies (Eu ~0.4-0.7 ppm) (typical of rhyolites), whereas HREEs (Tb, Ho, Tm) are elevated (~2-3 ppm). Patchy K-spar and quartz inclusions (PR-12, 91) have flat LREE patterns, and positive anomalies in Tb, Ho, and Tm. One K-spar inclusion (PR-91) has a ~5-50 fold increase in HREEs (Tb, Dy, Ho, Er, Tm) and U (35 ppm) relative to other MI. U-Pb and REE analyses of its zircon host are not unusual (1484 ± 21 Ma); its irregular shape

  1. Geochemical and Geochronologic Investigations of Zircon-hosted Melt Inclusions in Rhyolites from the Mesoproterozoic Pea Ridge IOA-REE Deposit, St. Francois Mountains, Missouri

    NASA Astrophysics Data System (ADS)

    Watts, K. E.; Mercer, C. N.; Vazquez, J. A.

    2015-12-01

    Silicic volcanic and plutonic rocks of an eroded Mesoproterozoic caldera complex were intruded and replaced by iron ore, and cross-cut by REE-enriched breccia pipes (~12% total REO) to form the Pea Ridge iron-oxide-apatite-REE (IOA-REE) deposit. Igneous activity, iron ore formation, and REE mineralization overlapped in space and time, however the source of REEs and other metals (Fe, Cu, Au) integral to these economically important deposits remains unclear. Melt inclusions (MI) hosted in refractory zircon phenocrysts are used to constrain magmatic components and processes in the formation of the Pea Ridge deposit. Homogenized (1.4 kbar, 1000°C, 1 hr) MI in zircons from rhyolites ~600 ft (PR-91) and ~1200 ft (PR-12) laterally from the ore body were analyzed for major elements by EPMA and volatiles and trace elements (H2O, S, F, Cl, REEs, Rb, Sr, Y, Zr, Nb, U, Th) by SHRIMP-RG. Metals (including Cu, Au) will be measured in an upcoming SHRIMP-RG session. U-Pb ages, Ti and REE were determined by SHRIMP-RG for a subset of zircon spots adjacent to MI (1458 ± 18 Ma (PR-12); 1480 ± 45 Ma (PR-91)). MI glasses range from fresh and homogeneous dacite-rhyolite (65-75 wt% SiO2) to heterogeneous, patchy mixtures of K-spar and quartz (PR-12, 91), and more rarely mica, albite and/or anorthoclase (PR-91). MI are commonly attached to monazite and xenotime, particularly along re-entrants and zircon rims (PR-91). Fresh dacite-rhyolite glasses (PR-12) have moderate H2O (~2-2.5 wt%), Rb/Sr ratios (~8) and U (~5-7 ppm), and negative (chondrite-normalized) Eu anomalies (Eu ~0.4-0.7 ppm) (typical of rhyolites), whereas HREEs (Tb, Ho, Tm) are elevated (~2-3 ppm). Patchy K-spar and quartz inclusions (PR-12, 91) have flat LREE patterns, and positive anomalies in Tb, Ho, and Tm. One K-spar inclusion (PR-91) has a ~5-50 fold increase in HREEs (Tb, Dy, Ho, Er, Tm) and U (35 ppm) relative to other MI. U-Pb and REE analyses of its zircon host are not unusual (1484 ± 21 Ma); its irregular shape

  2. Trace elements and REE fractionation in subsoils developed on sedimentary and volcanic rocks: case study of the Mt. Vulture area, southern Italy

    NASA Astrophysics Data System (ADS)

    Mongelli, Giovanni; Paternoster, Michele; Rizzo, Giovanna; Sinisi, Rosa

    2014-06-01

    There is an increasing interest in the distribution of rare earth elements (REEs) within soils, primarily as these elements can be used to identify pedogenetic processes and because soils may be future sources for REE extraction, despite much attention should be paid to the protection and preservation of present soils. Here, we evaluate the processes that control the distribution of REEs in subsoil horizons developed over differing lithologies in an area of low anthropogenic contamination, allowing estimates of the importance of source rocks and weathering. Specifically, this study presents new data on the distribution of REEs and other trace elements, including transition and high-field-strength elements, in subsoils developed on both Quaternary silica-undersaturated volcanic rocks and Pliocene siliciclastic sedimentary rocks within the Mt. Vulture area of the southern Apennines in Italy. The subsoils in the Mt. Vulture area formed during moderate weathering (as classified using the chemical index of alteration) and contain an assemblage of secondary minerals that is dominated by trioctahedral illite with minor vermiculite. The REEs, high-field-strength elements, and transition metals have higher abundances in subsoils that developed from volcanic rocks, and pedogenesis caused the Mt. Vulture subsoils to have REE concentrations that are an order of magnitude higher than typical values for the upper continental crust. This result indicates that the distribution of REEs in soils is a valuable tool for mineral exploration. A statistical analysis of inter-elemental relationships indicates that REEs are concentrated in clay-rich fractions that also contain significant amounts of low-solubility elements such as Zr and Th, regardless of the parent rock. This suggests that low-solubility refractory minerals, such as zircon, play a significant role in controlling the distribution of REEs in soils. The values of (La/Yb)N and (Gd/Yb)N fractionation indices are dependent on

  3. The influence of melt composition on the partitioning of REEs, Y, Sc, Zr and Al between forsterite and melt in the system CMAS

    NASA Astrophysics Data System (ADS)

    Evans, Thomas M.; O'Neill, Hugh St. C.; Tuff, James

    2008-12-01

    Partition coefficients for a range of Rare Earth Elements (REEs), Y, Sc, Al and Zr were determined between forsteritic olivine (nearly end-member Mg 2SiO 4) and ten melt compositions in the system CaO-MgO-Al 2O 3-SiO 2 (CMAS) at 1 bar and 1400 °C, with concentrations of the trace elements in the olivine and the melt measured by laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The REEs and Sc were added at levels sufficient to ensure that concentrations in the olivine were well above the detection limits. The REE partition coefficients (DREEol/melt) decrease with increasing silica in the melt, indicating strong bonding between REEO 1.5 and SiO 2 in the melt. The variation of DREEol/melt as a function of ionic radius is well described by the Brice equation for each composition, although a small proportion of this variation is due to the increase in the strength of the REEO 1.5-SiO 2 interactions in the melt with ionic radius. Scandium behaves very similarly to the REEs, but a global fit of the data from all ten melt compositions suggests that DScol/melt deviates somewhat from the parabolas established by the REE and Y, implying that Sc may substitute into olivine differently to that of the REEs. In contrast to the behaviour of the large trivalent cations, the concentration of Al in olivine is proportional to the square root of its concentration in the melt, indicating a coupled substitution in olivine with a high degree of short-range order. The lack of any correlation of REE partition coefficients with Al in olivine or melt suggests that the REE substitution in olivine is charge-balanced by cation vacancies. The partition coefficient of the tetravalent trace element Zr, which is highly incompatible in olivine, depends on the CaO content of the melt.

  4. Simple models for disequilibrium fractional melting and batch melting with application to REE fractionation in abyssal peridotites

    NASA Astrophysics Data System (ADS)

    Liang, Yan; Liu, Boda

    2016-01-01

    Disequilibrium melting arises when the kinetics of chemical exchange between a residual mineral and partial melt is sluggish compare to the rate of melting. To better understand the role of a finite crystal-melt exchange rate on trace element fractionation during mantle melting, we have developed a disequilibrium melting model for partial melting in an upwelling steady-state column. We use linear kinetics to approximate crystal-melt mass exchange rate and obtain simple analytical solutions for cases of perfect fractional melting and batch melting. A key parameter determining the extent of chemical disequilibrium during partial melting is an element specific dimensionless ratio (ε) defined as the melting rate relative to the solid-melt chemical exchange rate for the trace element of interest. In the case of diffusion in mineral limited chemical exchange, ε is inversely proportional to diffusivity of the element of interest. Disequilibrium melting is important for the trace element when ε is comparable to or greater than the bulk solid-melt partition coefficient for the trace element (k). The disequilibrium fractional melting model is reduced to the equilibrium perfect fractional melting model when ε is much smaller than k. Hence highly incompatible trace elements with smaller mobilities in minerals are more susceptible to disequilibrium melting than moderately incompatible and compatible trace elements. Effect of chemical disequilibrium is to hinder the extent of fractionation between residual solid and partial melt, making the residual solid less depleted and the accumulated melt more depleted in incompatible trace element abundances relative the case of equilibrium melting. Application of the disequilibrium fractional melting model to REE and Y abundances in clinopyroxene in abyssal peridotites from the Central Indian Ridge and the Vema Lithospheric Section, Mid-Atlantic Ridge revealed a positive correlation between the disequilibrium parameter ε and the

  5. The behaviour of REE and Zr-Hf fractionation in the volcanic waters of Nevado del Ruiz system (Colombia)

    NASA Astrophysics Data System (ADS)

    Inguaggiato, Claudio; Censi, Paolo; Zuddas, Pierpaolo; Makario Londoño, John; Chacón, Zoraida; Alzate, Diego; Brusca, Lorenzo; D'Alessandro, Walter

    2015-04-01

    The geochemical behaviour of Rare Earth Element (REE), Zr and Hf have been investigated in the thermal waters of Nevado del Ruiz volcanic system. These fluids are characterised by a wide range of pH ranging between 1.0 and 8.8. The acidic waters are sulphate dominated with different Cl/SO4 ratios. The Nevado del Ruiz waters allowed to investigate the behaviour of investigated elements in a wide spectrum of pH and chemical composition of water. The important role of the pH and the ionic complexes have been evidenced in the distribution of REE, Zr and Hf in the aqueous phase. The pH rules the precipitation of authigenic oxyhydroxides of Fe, Al producing changes in REE, Zr, Hf amount and strong anomalies of Cerium and Europium. Y-Ho and Zr-Hf (twin pairs) have different behaviour in strong acidic waters with respect to the water with higher pH. Yttrium and Ho have the same behaviour of Zr and Hf in waters with pH near neutral-to-neutral, showing super-chondritic ratios. The twin pairs showed to be sensitive to the co-precipitation and/or adsorption onto the surface of authigenic particulate suggesting an enhanced scavenging of Ho and Hf respect to Y and Zr, leading to super-chondritic ratios. In acidic waters a different behaviour of twin pairs occurs with chondritic Y/Ho ratios (reflecting the Y/Ho ratio of average local rock) and sub-chondritic Zr/Hf ratios. For the first time, Zr and Hf have been investigated in natural acidic fluids to understand the behaviour of these elements in extreme acidic conditions and different major anions chemistry. Zr/Hf molar ratio changes from 4.75 to 49.29 in water with pH<3.6. In strong acidic waters, a different fractionation of Zr and Hf have been recognised as function of major anion contents (Cl and SO4), suggesting the formation of complexes leading to sub-chondritic Zr/Hf molar ratios.

  6. Sorption of the Rare Earth Elements and Yttrium (REE-Y) in calcite: the mechanism of a new effective tool in identifying paleoearthquakes on carbonate faults

    NASA Astrophysics Data System (ADS)

    Moraetis, Daniel; Mouslopoulou, Vasiliki; Pratikakis, Alexandros

    2015-04-01

    A new tool for identifying paleoearthquakes on carbonate faults has been successfully tested on two carbonate faults in southern Europe (the Magnola Fault in Italy and the Spili Fault in Greece): the Rare Earth Element and Yttrium (REE-Y) method (Manighetti et al., 2010; Mouslopoulou et al., 2011). The method is based on the property of the calcite in limestone scarps to absorb the REE and Y from the soil during its residence beneath the ground surface (e.g. before its exhumation due to earthquakes). Although the method is established, the details of the enrichment mechanism are poorly investigated. Here we use published data together with new information from pot-experiments to shed light on the sorption mechanism and the time effectiveness of the REE-Y method. Data from the Magnola and Spili faults show that the average chemical enrichment is ~45%, in REE-Y while the denudation rate of the enriched zones is ~1% higher every 400 years due to exposure of the fault scarp in weathering. They also show that the chemical enrichment is significant even for short periods of residence time (e.g., ~100 years). To better understand the enrichment mechanism, we performed a series of pot experiments, where carbonate tiles extracted from the Spili Fault were buried into soil collected from the hanging-wall of the same fault. We irrigated the pots with artificial rain that equals 5 years of rainfall in Crete and at temperatures of 15oC and 25oC. Following, we performed sorption isotherm, kinetic and pH-edge tests for the europium (Eu), the cerium (Ce) and the ytterbium (Yt) that occur in the calcite minerals. The processes of adsorption and precipitation in the batch experiments are simulated by the Mineql software. The pot experiments indicate incorporation of the REE and Y into the surface of the carbonate tile which is in contact with the soil. The pH of the leached solution during the rain application range from 7.6 to 8.3. Nutrient release like Ca is higher in the leached

  7. Landslide-induced iron mobilisation shapes benthic accumulation of nutrients, trace metals and REE fractionation in an oligotrophic alpine stream

    NASA Astrophysics Data System (ADS)

    Johnston, Scott G.; Rose, Andrew L.; Burton, Edward D.; Webster-Brown, Jenny

    2015-01-01

    Large alpine landslides that entrain substantial organic material below the water table and create suspended floodplains may have long-term consequences for the mobilisation of redox sensitive elements, such as Fe, into streamwaters. In turn, the cycling of iron in aquatic systems can influence the fate of nutrients, alter primary productivity, enhance accumulation of trace metals and induce fractionation of rare earth elements (REE). In this study we examine a reach of a pristine oligotrophic alpine stream bracketing a 30 year-old landslide and explore the consequences of landslide-induced Fe mobilisation for aqueous geochemistry and the composition of benthic stream cobble biofilm. Elevated Fe2+ and Mn in landslide zone stream waters reflect inputs of circumneutral groundwater from the landslide debris-zone floodplain. Geochemical characteristics are consistent with reductive dissolution being a primary mechanism of Fe2+ and Mn mobilisation. Stream cobble biofilm in the landslide zone is significantly (P < 0.01) enriched in poorly crystalline Fe(III) (∼10-400 times background) and Mn (∼15-150 times background) (1 M HCl extractable; Fe(III)Ab). While the landslide zone accounts for less than ∼9% of the total stream length, we estimate it is responsible for approximately 60-80% of the stream's benthic biofilm load of poorly crystalline Fe(III) and Mn. Biofilm Fe(III) precipitates are comprised mainly of ferrihydrite, lepidocrocite and an organic-Fe species, while precipitate samples collected proximal to hyporheic seeps contain abundant sheath structures characteristic of the neutrophilic Fe(II)-oxidising bacteria Leptothrix spp. Stream-cobble Fe(III)-rich biofilm is accumulating PO43- (∼3-30 times background) and behaving as a preferential substrate for photosynthetic periphyton, with benthic PO43-, chlorophyll a, organic carbonHCl and total N all significantly positively correlated with Fe(III)Ab and significantly elevated within the landslide zone (P < 0

  8. Hydrothermal metasomatism of a peralkaline granite pegmatite, Khaldzan Buragtag massif, Mongolian Altai; complex evolution of REE-Nb minerals

    NASA Astrophysics Data System (ADS)

    Bagiński, Bogusław; Jokubauskas, Petras; Domańska-Siuda, Justyna; Kartashov, Pavel; Macdonald, Ray

    2016-09-01

    The low-temperature hydrothermal alteration of certain rare-metal minerals is recorded in a quartz-epidote metasomatite from the Tsakhirin Khuduk occurrence in the Khaldzan-Buragtag Nb-REE-Zr deposit, Mongolian Altai. A peralkaline granitic pegmatite was metasomatized by hydrothermal fluids released from associated intrusions, with the formation of, inter alia, chevkinite-(Ce), fergusonite-(Nd) and minerals of the epidote group. The textural pattern indicates recrystallization and coarsening of these phases. Later, low-temperature alteration by fluids resulted in the chevkinite-(Ce) being replaced by complex titanite-TiO2 -cerite-(Ce)-hingganite-hydroxylbastnasite-( Ce) assemblages. Calcite formed late-stage veins and patches. The hydrous fluids were poor in F and CO2 but had high Ca contents.

  9. Fluid inclusion studies of the Rodeo de Los Molles REE and Th deposit, Las Chacras Batholith, Central Argentina

    NASA Astrophysics Data System (ADS)

    Lira, Raul; Ripley, Edward M.

    1990-03-01

    The Rodeo de Los Molles rare earth element (REE) and thorium deposit is located in granitic rocks of the Las Chacras-Piedras Coloradas Batholith, in the southern block of the Eastern Pampean Ranges, Central Argentina. Mineralization occurs within an elongate (2 km × 0.6 km) body of alkalifeldspar granite (alaskite) localized along the northeastern edge of a composite batholith. The surrounding lithology is predominantly a biotite monzogranite. Both the alaskite and localized areas of quartz alkalifeldspar syenite within the alaskite have been produced by hydrothermal alteration of a late-crystallizing phase of the monzogranite. REE minerals are primarily of the cerium group and include britholite and allanite, both partially replaced by bastnaesite or thorbastnaesite. These minerals occur as nodules with quartz, fluorite, aegirine-augite, sphene, and Fe-Ti oxides within aplitic to pegmatoidal quartz alkalifeldspar syenite. Uranothorite, along with a second generation of fluorite and minor amounts of MnBa oxides, occurs in the alaskite as nodules, or within quartz-lined miarolitic cavities, but is not found with the Ce-mineralization. Studies of fluid inclusions contained in quartz and fluorite indicate a complex history of open-system fluid migration and interaction with monzogranite host rocks. Fluids responsible for REE mineralization and quartz deposition, along with initial alteration of the monzogranite to alaskite and quartz alkalifeldspar syenite, were of relatively high temperature (T h of fluid inclusions in quartz = 356-535°C) and moderate salinity (15-25 eq. wt% NaCl). Mixed CO 2H 2O fluids (XCO 2 = .13-.07) found as both primary and secondary inclusions within fluorite are representative of fluids involved in the replacement of britholite-allanite by bastnaesite and sphene, aegirine-augite, and plagioclase by calcite. Minimum pressures of mineral deposition estimated from H 2OCO 2NaCl phase relations range from 1 to 2 kbars. Secondary

  10. Some evidence for the base-metal potential of the Pretoria Group: stratigraphic targets, tectonic setting and REE patterns

    NASA Astrophysics Data System (ADS)

    Reczko, B. F. F.; Eriksson, P. G.; Snyman, C. P.

    1995-04-01

    The Timeball Hill and Silverton Formations of the 2.1 2.3 Ga Pretoria Group have regional lithological associations which are thought to have been favourable for the genesis of stratiform sulphide deposits. The observed association of carboniferous and pyritic black shales, tuffaceous material, stromatolitic carbonates and inferred turbidity current deposits is common in stratiform sulphide deposits of the sedimentary exhalative group. Massive sulphides in the Silverton Formation are compatible with a syngenetic brine discharge, probably related to deep fracture systems. The basal shales of the Timeball Hill Formation are significantly enriched in base-metals and Ba. Interlayered tuff beds at this stratigraphic level have PGE-contents of up to 1 g/t. The REE-geochemistry of Pretoria Group sedimentary rocks supports hydrothermal activity as an important factor in both stratigraphic units.

  11. Application of Markov Chain Monte Carlo Method to Mantle Melting: An Example from REE Abundances in Abyssal Peridotites

    NASA Astrophysics Data System (ADS)

    LIU, B.; Liang, Y.

    2015-12-01

    Markov chain Monte Carlo (MCMC) simulation is a powerful statistical method in solving inverse problems that arise from a wide range of applications, such as nuclear physics, computational biology, financial engineering, among others. In Earth sciences applications of MCMC are primarily in the field of geophysics [1]. The purpose of this study is to introduce MCMC to geochemical inverse problems related to trace element fractionation during concurrent melting, melt transport and melt-rock reaction in the mantle. MCMC method has several advantages over linearized least squares methods in inverting trace element patterns in basalts and mantle rocks. First, MCMC can handle equations that have no explicit analytical solutions which are required by linearized least squares methods for gradient calculation. Second, MCMC converges to global minimum while linearized least squares methods may be stuck at a local minimum or converge slowly due to nonlinearity. Furthermore, MCMC can provide insight into uncertainties of model parameters with non-normal trade-off. We use MCMC to invert for extent of melting, amount of trapped melt, and extent of chemical disequilibrium between the melt and residual solid from REE data in abyssal peridotites from Central Indian Ridge and Mid-Atlantic Ridge. In the first step, we conduct forward calculation of REE evolution with melting models in a reasonable model space. We then build up a chain of melting models according to Metropolis-Hastings algorithm to represent the probability of specific model. We show that chemical disequilibrium is likely to play an important role in fractionating LREE in residual peridotites. In the future, MCMC will be applied to more realistic but also more complicated melting models in which partition coefficients, diffusion coefficients, as well as melting and melt suction rates vary as functions of temperature, pressure and mineral compositions. [1]. Sambridge & Mosegarrd [2002] Rev. Geophys.

  12. The Pasamonte unequilibrated eucrite: Pyroxene REE systematic and major-, minor-, and trace-element zoning. [Abstract only

    NASA Technical Reports Server (NTRS)

    Pun, A.; Papike, J. J.

    1994-01-01

    We are evaluating the trace-element concentrations in the pyroxenes of Pasamonte. Pasamonte is a characteristic member of the main group eucrites, and has recently been redescribed as a polymict eucrite. Our Pasamonte sample contained eucritic clasts with textures ranging from subophitic to moderately coarse-grained. This study concentrates on pyroxenes from an unequilibrated, coarse-grained eucrite clast. Major-, minor-, and trace-element analyses were measured for zoned pyroxenes in the eucritic clast of Pasamonte. The major- and minor-element zoning traverses were measured using the JEOL 733 electron probe with an Oxford-Link imaging/analysis system. Complemenatry trace elements were then measured for the core and rim of each of the grains by SIMS. The trace elements analyzed consisted of eight REE, Sr, Y, and Zr. These analyses were performed on a Cameca 4f ion probe. The results of the CI chondrite normalized (average CI trace-element analyses for several grains and the major- and minor-element zoning patterns from a single pyroxene grain are given. The Eu abundance in the cores of the pyroxenes represents the detection limit and therefore the (-Eu) anomaly is a minimum. Major- and minor-element patterns are typical for igneous zoning. Pyroxene cores are Mg enriched, whereas the rims are enriched in Fe and Ca. Also, Ti and Mn are found to increase, while Cr and Al generally decrease in core-to-rim traverses. The cores of the pyroxenes are more depleted in the Rare Earth Elements (REE) than the rims. Using the minor- and trace-element concentrations of bulk Pasamonte and the minor- and trace-element concentrations from the cores of the pyroxenes in Pasamonte measured in this study, we calculated partition coefficients between pyroxene and melt. This calculation assumes that bulk Pasamonte is representative of a melt composition.

  13. Dust dispersal and Pb enrichment at the rare-metal Orlovka-Spokoinoe mining and ore processing site: insights from REE patterns and elemental ratios.

    PubMed

    Dolgopolova, Alla; Weiss, Dominik J; Seltmann, Reimar; Dulski, Peter

    2006-04-30

    Different geological, technogenic and environmental samples from the Orlovka-Spokoinoe Ta-Nb-Sn-W mining site and ore processing complex in Eastern Transbaikalia (Russia), were analysed for Pb, Y, Zr, Hf and rare earth elements (REE) to assess the effect of dust and metal dispersal on the environment within the Orlovka-Spokoinoe mining site. Potential source material analysed included ore-bearing and barren granites, host rocks, tailing pond sediments, and ore concentrates. Lichens and birch leaves were used as receptor samples. The REE enrichment relative to chondrite, the extent of the Eu anomalies, the enrichments of heavy REE (HREE), and Zr/Hf and Yb/Y ratios suggest that tailings, barren granites, and metasedimentary host rocks are the main sources of dust in the studied mining environment. In addition, calculated lead enrichment (relative to host rocks) suggests that the environment is polluted with Pb. Our results clearly demonstrate the potential of REE patterns and elemental ratios as a reliable technique to trace dust and metals sources and dispersal within a confined mining area offering a new tool for environmental assessment studies.

  14. Karrat REE mineralization on Niaqornakavsak and extension on Umiamako Nuna, West Greenland: mineralogic, geochronologic, and carbon and oxygen isotope constraints on the origin

    NASA Astrophysics Data System (ADS)

    Mott, A.; Bird, D. K.; Grove, M.; Bernstein, S.; Mackay, H.; Rose, N.

    2011-12-01

    The Karrat rare earth element (REE) mineralization is located in the Niaqornakavsak (NIAQ) area of Qeqertarssuaq Island in Greenland (~72°N). A mineralized horizon occurs as a single distinct layer (35-40° dip) within an amphibolite host rock of the Qeqertarssuaq Formation: a member of the Paleoproterozoic Karrat Group sequence. Average Yttrium + REE-oxide (YREEO) concentration is ~1.0 wt. % with concentrations up to 2.59 wt. % over one meter intervals. Eight drill holes across three locations on NIAQ allow for an estimated true thickness of REE enrichment (YREEO ≥ 0.2 wt. %) of 29-38m in the east and central area, and a fault restricted thickness at the site in the west of 16m (at surface) to 28m (at depth). Two distinct metasomatic reaction zones comprise the mineralized horizon and are universal across NIAQ: the upper unit (CCA ~1.5 %YREEO) has a primary mineralogy of calcite + ankerite + fluorite (>50%), grunerite, cummingtonite, magnetite, fergusonite, bastnasite, allanite, and monazite, while the lower unit (BLC) consists of biotite (>50%), calcite, ilmenite, magnetite, allanite, fergusonite, and monazite. An extension of the Karrat REE deposit outcrops 7 km to the east on Umiamako Nuna. Hand samples from Umiamako Nuna similar to CCA (YREEO up to 2.4 wt. %) have been collected, but two exploratory drill holes revealed the majority of the REE enriched zone is comparable to the mineralogy of the incomplete reaction zone around CCA on NIAQ with concentrations of YREEO ranging from 0.5-1.0 wt. % with an estimated thickness of 15m. The mineralization consists of Ca-amphiboles, biotite, calcite, pyrite, albite, and garnet. Enrichment of REE continues to a depth of 60m from vein mineralization. In addition, a secondary occurrence at depth can be found on Umiamako Nuna tens of meters below the primary mineralized horizon, which is characterized by high modal concentrations of calcite, fluorite, and amphiboles. Carbon and oxygen isotope analyses of 145 carbonate

  15. A granulite record of multistage metamorphism and REE behavior in the Dabie orogen: Constraints from zircon and rock-forming minerals

    NASA Astrophysics Data System (ADS)

    Wang, Shui-Jiong; Li, Shu-Guang; An, Shi-Chao; Hou, Zhen-Hui

    2012-04-01

    A combined study of mineral inclusions, U-Pb ages and trace elements was carried for zircon and coexisting minerals from granulite in the North Dabie Terrane (NDT) of the Dabie-Sulu ultrahigh-pressure metamorphic (UHP) zone, east-central China. The results provide insights into the exhumation history of NDT and into rare earth element (REE) behavior during retrogression. Besides inherited cores and one magmatic rim, zircons separated from the granulite record three episodes of metamorphism under different P-T conditions: (1) 223.8 ± 2.3 Ma for domains that contain Grt + Cpx ± Rt ± F - Ap ± Aln inclusions without plagioclase and show flat HREE patterns without negative Eu anomalies, representing peak eclogite-facies event; (2) 213.3 ± 2.1 Ma for domains that contain Pl ± Cpx ± Grt ± Qtz ± Ap inclusions and show rather flat HREE patterns with negative Eu anomalies, corresponding to granulite-facies retrogression; (3) 199.9 ± 3.3 Ma for domains that contain Amp ± Pl ± Qtz ± Ap inclusions and show high REE contents with steep HREE patterns and remarkable negative Eu anomalies, representing amphibolite-facies overprinting. Therefore, the UHP eclogite in NDT experienced decompression heating during the initial exhumation, with local hydration in the late stage of the Triassic continental collision. Garnet in the granulite is composed of a corroded core with embayed outline and spongy texture and an overgrowth rim. There is equilibrium distribution of HREE between garnet rim and granulite-facies zircon domain, confirming the geological interpretation of 213.3 ± 2.1 Ma for the granulite-facies metamorphism. There is the prograde HREE depletion in porphyroblastic garnet from core to rim and the continuous decrease of HREE from the eclogitic to granulitic zircons, suggesting that the metamorphic transformation from eclogite-facies to granulite-facies took place in a closed system. On the other hand, the amphibolitic zircons show steep HREE patterns and

  16. Sedimentology of a glaciofluvial landsystem, Lough Ree area, Central Ireland: implications for ice margin characteristics during Devensian deglaciation

    NASA Astrophysics Data System (ADS)

    Delaney, Catherine

    2002-05-01

    Eskers in a glaciofluvial landsystem in the Lough Ree area, Central Ireland, exhibit two orientations. The most southerly esker in the area, the Athlone Esker, forms part of a dendritic esker system with paleocurrent directions indicating eastward drainage, while the Rooskagh Esker and associated eskers and kames immediately to the north were formed during southward drainage. Sediments indicate that sharp-crested, steep-sided sections of both ridges were formed within subglacial tunnels, while fan-shaped and flat-topped areas were formed as subaqueous outwash fans and deltas in standing water immediately in front of an ice-margin. The deposition of ice-marginal deposits indicating southward paleoflows against the side of the eastward flowing Athlone Esker indicates a 90° shift in the direction of ice surface slope, and a similar shift in the likely orientation of the ice margin. The absence of any evidence of intermediate ice- or water-flow directions indicates that the shift reflects a recession of ice, followed by a readvance from the north.

  17. Morphological and molecular characterisation of Ditrachybothridium macrocephalum Rees, 1959 (Cestoda: Diphyllidea) from Galeus melastomus Rafinesque in the Western Mediterranean.

    PubMed

    Dallarés, Sara; Pérez-Del-Olmo, Ana; Carrassón, Maite; Kuchta, Roman

    2015-09-01

    New morphological, molecular and ecological data for Ditrachybothridium macrocephalum Rees, 1959 (Cestoda: Diphyllidea) are presented and discussed based on specimens recovered from the blackmouth catshark Galeus melastomus Rafinesque (Scyliorhinidae) in the Western Mediterranean. A redescription of the plerocercus of this parasite is provided and new data on immature and mature worms including the first description of the eggs are reported, based on light and scanning electron microscopy observations. Analysis of 28S rDNA (domains D1-D3) sequences from plerocerci, immature and adult specimens revealed that they are conspecific with specimens from the North East Atlantic. Although previous authors considered that museum specimens identified as D. macrocephalum may represent more than one species, examination of type- and voucher material revealed no relevant morphological differences between museum specimens and the present material. Information on infection levels of D. macrocephalum is provided from a large number of host specimens (n = 170). This species was more abundant in juvenile than in adult hosts and on the middle slope than on the upper slope; this may be related to ontogenetic and bathymetric diet shifts of G. melastomus.

  18. REE, Uranium (U) and Thorium (Th) contents in Betula pendula leaf growing around Komsomolsk gold concentration plant tailing (Kemerovo region, Western Siberia, Russia)

    NASA Astrophysics Data System (ADS)

    Yusupov, D. V.; Karpenko, Yu A.

    2016-09-01

    The article deals with the research findings of peculiarities of REE, Uranium and Thorium distribution in the territory surrounding the tailing of former Komsomolsk gold concentration plant according to the data from Betula pendula leaf testing. In the leaf element composition the slight deficiency of MREE and substantial excess of HREE are presented. In the nearest impacted area around the tailing, La, Yb, U and Th content, and Th/U ratio are lower than in the distant buffer area. It is shown, that value of Th/U ratio and REE can be an indicator for geochemical transformations of technogenic landscapes in mining districts. The results of the research can be used for biomonitoring of the territory around the tailing.

  19. Removal of high-salinity matrices through polymer-complexation-ultrafiltration for the detection of trace levels of REEs using inductively coupled plasma mass spectrometry.

    PubMed

    Duan, Hualing; Lin, Jijun; Gong, Zhenbin; Huang, Jiahua; Yang, Shifeng

    2015-10-01

    The polymer-complexation-ultrafiltration (PCUF) technique was applied to separate trace levels of rare earth elements (REEs), including scandium, yttrium and the lanthanides, from high-salinity matrices prior to their determination by inductively coupled plasma mass spectrometry (ICP-MS). The REEs were converted into REE-polymer complexes using the water-soluble polymer polyacrylic acid (PAA) at a specified pH, retained on the ultrafiltration membrane of centrifugal filter units, and finally eluted using diluted nitric acid to achieve separation from matrices with relatively high levels of various inorganic ions, such as sodium, potassium, calcium, magnesium, and chlorine ions. Numerous factors affecting the PCUF efficiency were optimized. The optimal conditions included the addition of 30 mg L(-1) of PAA, a pH of 7.5, a reaction time of 40 min at room temperature, and 5.0 mL of 3% nitric acid (v/v) eluent. Under these conditions, the analytes were quantitatively separated and recovered, with a resulting relative standard deviation (RSD) of less than 4.0% (0.05 µg L(-1), n=5) and standard addition recoveries between 89.2% (La) and 95.8% (Sm) for matrices of various salinities. The blank samples for the method ranged from 0.0003 µg L(-1) (Dy) to 0.0031 µg L(-1) (Sc), and the limits of quantification (LOQs, 10σ) were between 0.0006 µg L(-1) (Dy) and 0.0026 µg L(-1) (Sc). Furthermore, the salinity of the sample exhibited no effect on the REE-polymer complex formation process. Finally, the method was successfully applied for the determination of trace levels of dissolved Sc, Y, and lanthanides in coastal and estuarine seawater samples.

  20. Enrichment of Rare Earth and Niobium from a REE-Nb-Fe Associated Ore via Reductive Roasting Followed by Magnetic Separation

    NASA Astrophysics Data System (ADS)

    Liu, Mudan; You, Zhixiong; Peng, Zhiwei; Li, Xiang; Li, Guanghui

    2016-02-01

    REE-Nb-Fe ore is a typical refractory resource rich in valuable elements. In this article, coal-based reductive roasting followed by magnetic separation is proposed to recover rare earth element (REE), niobium (Nb), and powdered metallic iron (Fe) concentrate from a REE-Nb-Fe raw concentrate containing 31.9% total iron grade (TFe), 3.2% rare earth oxides (REO), and 2.9% Nb2O5. Sodium sulfate is employed to enhance the reduction of iron oxide and to facilitate the growth of metallic iron grains. A magnetic fraction with TFe of 89.3%, iron metallization of 95.8% and iron recovery of 91.5% is obtained by magnetic separation after the raw concentrate is reduced to 1100°C for 120 min in the presence of 15 wt.% sodium sulfate. The contents of rare earth and niobium in the nonmagnetic fraction are enriched to 5.4% (REO) and 4.6% (Nb2O5) with recoveries of 96.1% and 95.8%, respectively. The TFe in the nonmagnetic fraction obtained after the separation is decreased to 4.8% accordingly. The reactions between sodium sulfate and SiO2/Al2O3 enhance the reduction by destroying the mineral structure. The separation of iron from rare earth and niobium is highly improved as metallic iron grains grow markedly when roasted in the presence of sodium sulfate.

  1. Dynamics of REE accumulation and fractionation in the subcolloidal fraction of bottom sediments in the Razdol'naya River-Amur Bay section, Sea of Japan

    NASA Astrophysics Data System (ADS)

    Polyakov, D. M.

    2016-05-01

    The REE contents (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) are determined by atomic emission spectroscopy in the subcolloidal fraction of bottom sediments in the Razdol'naya River-Amur Bay section. The mean contents of lanthanides in soils and river bottom sediments (before the mixing zone) are calculated. The increase in REE content and the fractioning in the series from light to middle and heavy REE in sediments of different estuary zones (river, water mixing, and marine), with the latter related to flocculation, sorption on iron and manganese hydroxides, clay minerals (hydromica, smectites), and lifetime accumulation of marine plankton, are dtermined. Via extraction of 0.5 N sodium hydroxide solution, the content of lanthanides associated with humic substances of subcolloidal fraction from the Amur Bay sediments are determined: 1.3 to 8.2% of La; 1.1 to 11% of Ce; and 0.3 to 1.5 of Gd.

  2. Fluid-mediated alteration of (Y,REE,U,Th)-(Nb,Ta,Ti) oxide minerals in granitic pegmatite from the Evje-Iveland district, southern Norway

    NASA Astrophysics Data System (ADS)

    Duran, Charley J.; Seydoux-Guillaume, Anne-Magali; Bingen, Bernard; Gouy, Sophie; de Parseval, Philippe; Ingrin, Jannick; Guillaume, Damien

    2016-10-01

    We document the textural relations and chemical composition of (Y,REE,U,Th)-(Nb,Ta,Ti) oxide minerals in a granitic pegmatite from the Evje-Iveland district, southern Norway, using a combination of scanning and transmission electron microscopy, electron probe micro-analysis and infrared absorption spectroscopy. The (Y,REE,U,Th)-(Nb,Ta,Ti) oxide mineral is euxenite, which is strongly radiation damaged and surrounded by radial fractures. Within euxenite grains, three domains of distinct composition comprising unaltered, intermediate and altered euxenite, have been identified. In most cases pyrochlore occurs as corroded grain boundaries around euxenite and within relict fractures. Intermediate and altered euxenite are depleted in U, Pb, Ti, Nb, and Y, but enriched in Si and Ca relative to unaltered euxenite. Pyrochlore is also enriched in Fe, Pb, Zr and LREE relative to all euxenite phases. Altered domains of euxenite have deficient analytical totals and contain O-H. These domains are metamict and contain nanopores and nanodomains enriched in U and Ca. We suggest that as radiation damage accumulated in euxenite, radial fractures developed around the euxenite grains, thus allowing fluid infiltration. In the presence of fluid, euxenite was replaced by secondary euxenite then pyrochlore, owing to dissolution-precipitation and diffusion reactions. During alteration, U and the strategic metals Nb, Ti, and REE were mobilized at both the nanoscale and the scale of the pegmatite.

  3. REE variation in alkaline mafic lavas across the North Tanzanian Divergence zone, a possible indicator of varying lithospheric thickness

    NASA Astrophysics Data System (ADS)

    Mana, S.; Carr, M. J.; Feigenson, M.; Furman, T.; Swisher, C. C.

    2012-12-01

    systematic REE variations (Sm/Yb versus La/Sm) that are consistent with different degrees of partial melting (La/Sm), and varying amounts of garnet and amphibole in the source (Sm/Yb). Many of the more evolved samples have greater radiogenic isotopic ratios and evolve via assimilation and fractional crystallization to lower Sm/Yb and higher La/Sm. Different degree of partial melting may reflect heat flow variations, while heterogeneity in the source is consistent with pressure conditions that imply changes in the depth of melting. In fact, REE abundances of key NTD volcanics (e.g. Essimingor) indicate melting in the garnet and phlogopite stability zone indicating the presence of a relatively thick lithosphere, while the absence of garnet indicate areas characterized by thinning of the lithosphere. MacIntyre, R.M., Mitchell, J.G., Dawson, J.B., 1974. Age of fault movements in Tanzanian sector of East African Rift System. Nature 247, 354-356.

  4. Multiple Basinal Fluid Events in the Lower Belt Supergroup, Montana: Constraints From CHIME Ages and REE Patterns of Monazites

    NASA Astrophysics Data System (ADS)

    Gonzalez-Alvarez, I.; Kusiak, M. A.

    2004-05-01

    Chemical dates (CHIME) on 105 spots and REE patterns of monazites were obtained from coarse sandstones and siltstones in the Mesoproterozoic siliciclastic Appekunny and Grinnell formations, lower Belt Supergroup, Montana, by EMPA. At least three post-depositional events induced by basinal fluids can be recognized: (a) red coloration accompanied by a major K-addition; (b) a green overprint of red siltstones; and (c) dolomitization. Fluid advection in the unmineralized lower Belt is pervasive and may have been alkaline and oxidizing. These three events progressively modified the primary geochemical characteristics of the siliciclastic rocks. Calculated ages show similar ranges in the fine and coarse-grained facies. For siltstones there are two age clusters: (1) at 1,801 ± 21 to 1,968 ± 26 Ma, as well as (2) at 854 ± 7 to 962 ± 13 Ma. Coarse sandstones show similar age clusters (3) at 1,831 ± 14 to 1,982 ± 12 Ma, and (4) at 803 ± 6 to 944 ± 9 Ma. A wide range of dates plots between the clusters for both facies. Clusters (1) and (3) are interpreted as the result of detrital monazites from a source area ~1.8 to 1.9 Ga old. Mineralogical variations and trace element systematic reveal basinal brines, which mobilized MREE and HREE, locally generating secondary monazites, influencing large domains of the lower Belt. The lower Belt Supergroup is estimated to have been deposited between 1.47 Ga and 1.45 Ga; consequently, the second age cluster for sandstones and siltstones is viewed as constraining the timeframe of a major basinal fluid event at ~0.80 to 0.96 Ga. That event is clearly distinct from the hydrothermal system associated with the Sullivan sedex base metal deposit at the base of the Belt. Ages between the clusters are interpreted either as secondary, formed during additional basinal fluid events or as reset of detrital monazites. Accordingly, the Belt basin was intermittently an open system to fluids from ~1.47 to ~0.80 Ga. Chondrite-normalized REE patterns

  5. Origin of the Rubian carbonate-hosted magnesite deposit, Galicia, NW Spain: mineralogical, REE, fluid inclusion and isotope evidence

    NASA Astrophysics Data System (ADS)

    Kilias, Stephanos P.; Pozo, Manuel; Bustillo, Manuel; Stamatakis, Michael G.; Calvo, José P.

    2006-10-01

    The Rubian magnesite deposit (West Asturian—Leonese Zone, Iberian Variscan belt) is hosted by a 100-m-thick folded and metamorphosed Lower Cambrian carbonate/siliciclastic metasedimentary sequence—the Cándana Limestone Formation. It comprises upper (20-m thickness) and lower (17-m thickness) lens-shaped ore bodies separated by 55 m of slates and micaceous schists. The main (lower) magnesite ore body comprises a package of magnesite beds with dolomite-rich intercalations, sandwiched between slates and micaceous schists. In the upper ore body, the magnesite beds are thinner (centimetre scale mainly) and occur between slate beds. Mafic dolerite dykes intrude the mineralisation. The mineralisation passes eastwards into sequence of bedded dolostone (Buxan) and laminated to banded calcitic marble (Mao). These show significant Variscan extensional shearing or fold-related deformation, whereas neither Rubian dolomite nor magnesite show evidence of tectonic disturbance. This suggests that the dolomitisation and magnesite formation postdate the main Variscan deformation. In addition, the morphology of magnesite crystals and primary fluid inclusions indicate that magnesite is a neoformed hydrothermal mineral. Magnesite contains irregularly distributed dolomite inclusions (<50 μm) and these are interpreted as relics of a metasomatically replaced dolostone precursor. The total rare earth element (REE) contents of magnesite are very similar to those of Buxan dolostone but are depleted in light rare earth elements (LREE); heavy rare earth element concentrations are comparable. However, magnesite REE chondrite normalised profiles lack any characteristic anomaly indicative of marine environment. Compared with Mao calcite, magnesite is distinct in terms of both REE concentrations and patterns. Fluid inclusion studies show that the mineralising fluids were MgCl2-NaCl-CaCl2-H2O aqueous brines exhibiting highly variable salinities (3.3 to 29.5 wt.% salts). This may be the result

  6. A possible difference in cooling rates recorded in REE in coexisting pyroxenes in peridotites from supra-subduction ophiolites and mid-ocean ridges

    NASA Astrophysics Data System (ADS)

    Dygert, N. J.; Liang, Y.; Kelley, K. A.

    2013-12-01

    Recently a REE-in-two-pyroxene thermometer was developed for mafic and ultramafic rocks [1]. This new thermometer is based on temperature sensitive REE partition coefficients between coexisting pyroxenes and calibrated against laboratory partitioning data. Because REE diffusion rates in pyroxene are relatively slow, the thermometer reads a higher temperature than major element based pyroxene thermometers. The difference between major and trace element derived temperatures depends primarily on cooling rate. Here we report new trace element data for peridotites from Trinity and Josephine ophiolites and a modern supra-subduction zone (SSZ) ophiolite analogue (the Mariana trench) determined by laser ablation ICP-MS. We inverted temperatures from the new data and globally distributed ophiolitic peridotite from eight literature studies (Figure 1). Data quality was carefully monitored leaving temperatures from 65 samples. Individual ophiolites usually have temperatures clustered within a range of a few hundred degrees, but the temperature range for the global dataset is greater than 700°C (688-1401°C). Temperatures calculated for the same samples using the two pyroxene thermometer of Brey and Köhler [2] are considerably lower (564-1049°C). REE temperatures are plotted against the major element temperatures [2] in Figure 1. Abyssal peridotites reported in [1] are shown by the peach field. Much of the ophiolite data plots farther from the blue 1:1 line than the abyssal peridotites, suggesting SSZ lithospheric mantle may cool more rapidly at those ophiolites. Fast cooling can be attributed to one or more dynamic differences between mid-ocean ridge (MOR) environments and supra-subduction environments, such as enhanced hydrothermal circulation, thinner oceanic crust, or rapid cooling due to basin closure and obduction. We note that several ophiolites appear to cool more slowly than the abyssal peridotites, however in those samples geochemical evidence suggests secondary

  7. Origin and evolution of the Nakhla meteorite inferred from the Sm-Nd and U-Pb systematics and REE, Ba, Sr, Rb and K abundances

    USGS Publications Warehouse

    Nakamura, N.; Unruh, D.M.; Tatsumoto, M.; Hutchison, R.

    1982-01-01

    Analyses of Sm-Nd and U-Th-Pb systematics, REE, Ba, Sr, Rb and K concentrations were carried out for whole rock and mineral separates from the Nakhla meteorite. The 1.26 ??.07 b.y. Sm-Nd age obtained in this work is in good agreement with those previously obtained by the Rb-Sr and Ar-Ar methods. The high initial ??{lunate}Nd value of +16 suggests that Nakhla was derived from a light REE-depleted, old planetary mantle source. U-Th-Pb data, after correction for pre-analytical terrestrial Pb contamination assuming an age of 1.26 b.y., suggest that the age of the Nakhla source is ???4.33 b.y. The agreement in the age determined by three independent radiometric methods and the high initial ??{lunate}Nd value strongly suggest that the 1.3 b.y. age dates one thorough igneous event in the parent body which not only reset these isotopic systems but also established the chemical and petrologic characteristics observed for the Nakhla meteorite. Using a three-stage Sm-Nd evolution model in combination with LIL element data and estimated partition coefficients, we have tested partial melting and fractional crystallization models to estimate LIL element abundances in a possible Nakhla source. Our model calculations suggest that partial melting of the light REE-depleted source followed by extensive fractional crystallization (???50%) of the partial melt could account for the REE abundances in the Nakhla constituent minerals. The estimated source is depleted in the light REE, Ba, Rb and K and therefore may resemble the MORB source in the earth's upper mantle or the upper 60-300 km of the moon. The significantly younger age of Nakhla than the youngest lunar rock; the young differentiation age inferred from the U-Th-Pb data, and the estimated LIL element abundances (including those of K, U and Th) in the source suggest that the Nakhla meteorite may have been derived from a relatively large, well-differentiated planetary body such as Mars. ?? 1982.

  8. Sedimentary carbonate-hosted giant Bayan Obo REE-Fe-Nb ore deposit of Inner Mongolia, China; a cornerstone example for giant polymetallic ore deposits of hydrothermal origin

    USGS Publications Warehouse

    Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Tatsumoto, M.; Junwen, Wang; Conrad, J.E.; McKee, E.H.; Zonglin, Hou; Qingrun, Meng; Shengguang, Huang

    1997-01-01

    Detailed, integrative field and laboratory studies of the textures, structures, chemical characteristics, and isotopically determined ages and signatures of mineralization of the Bayan Obo deposit provided evidence for the origin and characteristics favorable for its formation and parameters necessary for defining giant polymetallic deposits of hydrothermal origin. Bayan Obo is an epigenetic, metasomatic, hydrothermal rare earth element (REE)-Fe-Nb ore deposit that is hosted in the metasedimentary H8 dolostone marble of the Middle Proterozoic Bayan Obo Group. The metasedimentary sequence was deposited on the northern continental slope of the North China craton. The mine area is about 100 km south of the suture marking Caledonian subduction of the Mongolian oceanic plate from the north beneath the North China craton. The mineralogy of the deposit is very complex, consisting of more than 120 different minerals, some of which are epigenetic minerals introduced by hydrothermal solutions, and some of which are primary and secondary metamorphic minerals. The major REE minerals are monazite and bastnaesite, whereas magnetite and hematite are the dominant Fe-ore minerals, and columbite is the most abundant Nb mineral. Dolomite, alkali amphibole, fluorite, barite, aegirine augite, apatite, phlogopite, albite, and microcline are the most widespread gangue minerals. Three general types of ores occur at Bayan Obo: disseminated, banded, and massive ores. Broad zoning of these ore types occurs in the Main and East Orebodies. Disseminated ores are in the outermost zone, banded ores are in the intermediate zone, and massive ores are in the cores of the orebodies. On the basis of field relations, host rocks, textures, structures, and mineral assemblages, many varieties of these three types of ores have been recognized and mapped. Isotopic dating of monazite, bastnaesite, aeschynite, and metamorphic and metasomatic alkali amphiboles associated with the deposit provides constraints

  9. Large sedimentary aquifer systems functioning. Constraints by classical isotopic and chemical tools, and REE in the Eocene sand aquifer, SW France

    NASA Astrophysics Data System (ADS)

    Petelet-Giraud, E.; Negrel, P. J.; Millot, R.; Guerrot, C.; Brenot, A.; Malcuit, E.

    2010-12-01

    continuous decrease of water levels in the IMS aquifer for instance constitute major indicators to be taken into account for water management at the aquifer system scale. Major elements variability was interpreted in terms of water-rock interactions in these confined systems isolated from anthropogenic influence, with the main role played by evaporites on the water salinity (up to 2.5 g.L-1). Rare Earth Elements (REE) were also analysed in some groundwater samples, resulting in a large variability of UCC normalized-REE patterns, ΣREE ranging from 1.9 to 50.6 µg.L-1, with no dependence on TDS. For instance, interaction with carbonates delivers REE flat patterns and highest ΣREE. The REE patterns and control by key parameters are investigated in order to test REE as a potential supplementary geochemical tracer to recognize the aquifer type hosting groundwater.

  10. Seawater-like trace element signatures (REE + Y) of Eoarchaean chemical sedimentary rocks from southern West Greenland, and their corruption during high-grade metamorphism

    NASA Astrophysics Data System (ADS)

    Friend, C. R. L.; Nutman, A. P.; Bennett, V. C.; Norman, M. D.

    2008-02-01

    Modern chemical sediments display a distinctive rare earth element + yttrium (REE + Y) pattern involving depleted LREE, positive La/La*SN, Eu/Eu*SN, and YSN anomalies (SN = shale normalised) that is related to precipitation from circumneutral to high pH waters with solution complexation of the REEs dominated by carbonate ions. This is often interpreted as reflecting precipitation from surface waters (usually marine). The oldest broadly accepted chemical sediments are c. 3,700 Ma amphibolite facies banded iron-formation (BIF) units in the Isua supracrustal belt, Greenland. Isua BIFs, including the BIF international reference material IF-G are generally considered to be seawater precipitates, and display these REE + Y patterns (Bolhar et al. in Earth Planet Sci Lett 222:43 60, 2004). Greenland Eoarchaean BIF metamorphosed up to granulite facies from several localities in the vicinity of Akilia (island), display REE + Y patterns identical to Isua BIF, consistent with an origin by chemical sedimentation from seawater and a paucity of clastic input. Furthermore, the much-debated magnetite-bearing siliceous unit of “earliest life” rocks (sample G91/26) from Akilia has the same REE + Y pattern. This suggests that sample G91/26 is also a chemical sediment, contrary to previous assertions (Bolhar et al. in Earth Planet Sci Lett 222:43 60, 2004), and including suggestions that the Akilia unit containing G91/26 consists entirely of silica-penetrated, metasomatised, mafic rock (Fedo and Whitehouse 2002a). Integration of our trace element data with those of Bolhar et al. (Earth Planet Sci Lett 222:43 60, 2004) demonstrates that Eoarchaean siliceous rocks in Greenland, with ages from 3.6 to 3.85 Ga, have diverse trace element signatures. There are now geographically-dispersed, widespread examples with Isua BIF-like REE + Y signatures, that are interpreted as chemically unaltered, albeit metamorphosed, chemical sediments. Other samples retain remnants of LREE depletion but

  11. A comparative study of sample dissolution techniques and plasma-based instruments for the precise and accurate quantification of REEs in mineral matrices.

    PubMed

    Whitty-Léveillé, Laurence; Turgeon, Keven; Bazin, Claude; Larivière, Dominic

    2017-04-08

    The recent commercialisation of inductively coupled plasma tandem mass spectrometric (ICP-MS/MS) instruments has provided analytical chemists with a new tool to properly quantify atomic composition in a variety of matrices with minimal sample preparation. In this article, we report on our assessment of the compatibility of 3 sample preparation techniques (open-vessel acid digestion, microwave digestion and alkaline fusion) for the quantification of rare earth elements (REEs) in mineral matrices. The combination of the high digestion temperatures (1050 °C) and using LiBO2 as a flux was the most effective strategy for the digestion of all rare earth elements in mineral matrices and was compatible with ICP-MS/MS measurements. We also assessed the analytical performances of ICP-MS/MS against other plasma-based instrumentation (microwave induced plasma and inductively coupled plasma atomic emission spectroscopy (MIP-AES and ICP-AES, respectively) and single quadrupole inductively coupled plasma mass spectrometry (ICP-MS). The comparative study showed that the concentrations obtained by ICP-MS/MS are in excellent agreement with the certified reference material values, and much more suited than the other analytical techniques tested for the quantification of REEs, which exhibited low detectability and/or spectral interferences for some elements/isotopes. Finally, the ruggedness of the analytical protocol proposed which combines a rapid sample dissolution step performed by an automated fusion unit and an ICP-MS/MS as a detector was established using various certified mineral matrices containing variable levels of REEs.

  12. Fluid-driven destabilization of REE-bearing accessory minerals in the granitic orthogneisses of North Veporic basement (Western Carpathians, Slovakia)

    NASA Astrophysics Data System (ADS)

    Ondrejka, M.; Putiš, M.; Uher, P.; Schmiedt, I.; Pukančík, L.; Konečný, P.

    2016-10-01

    A variety of rare earth elements-bearing (REE) accessory mineral breakdowns were identified in granitic orthogneisses from the pre-Alpine basement in the Veporic Unit, Central Western Carpathians, Slovakia. The Ordovician granitic rocks were subjected to Variscan metamorphic-anatectic overprint in amphibolite facies. Chemical U-Th-Pb dating of monazite-(Ce) and xenotime-(Y) reveal their primary magmatic Lower to Middle Ordovician age (monazite: 472 ± 4 to 468 ± 6 Ma and xenotime: 471 ± 13 Ma) and/or metamorphic-anatectic Variscan (Carboniferous, Visean) age (monazite: 345 ± 3 Ma). Younger fluid-rock interactions caused breakdown of primary magmatic and/or metamorphic-anatectic monazite-(Ce), xenotime-(Y), fluorapatite and allanite-(Ce). Fluid-induced breakdown of xenotime-(Y) produced numerous tiny uraninite inclusions within the altered xenotime-(Y) domains. The monazite-(Ce) breakdown produced secondary egg-shaped coronal structures of different stages with well-developed concentric mineral zones. Secondary sulphatian monazite-(Ce) (up to 0.15 apfu S) occasionally formed along fluorapatite fissures. Localized fluorapatite and monazite-(Ce) recrystallization resulted in a very fine-grained, non-stoichiometric mixture of REE-Y-Fe-Th-Ca-P-Si phases. Finally, allanite-(Ce) decomposed to secondary REE carbonate minerals (members of the bastnäsite and synchysite groups) and calcite in some places. Although the xenotime alteration and formation of uraninite inclusions is believed to be the result of dissolution-reprecipitation between early magmatic xenotime and late-magmatic granitic fluids, the monazite, apatite and allanite breakdowns were driven by metamorphic hydrothermal fluids. While earlier impact of post-magmatic fluids originated probably from Permian acidic volcanic and microgranitic veins crosscutting the orthogneisses, another fluid-rock interaction event most likely occurred during Late Cretaceous metamorphism in the Veporic basement and covering

  13. 2nd International Symposium on Fundamental Aspects of Rare-earth Elements Mining and Separation and Modern Materials Engineering (REES-2015)

    NASA Astrophysics Data System (ADS)

    Tavadyan, Levon, Prof; Sachkov, Viktor, Prof; Godymchuk, Anna, Dr.; Bogdan, Anna

    2016-01-01

    The 2nd International Symposium «Fundamental Aspects of Rare-earth Elements Mining and Separation and Modern Materials Engineering» (REES2015) was jointly organized by Tomsk State University (Russia), National Academy of Science (Armenia), Shenyang Polytechnic University (China), Moscow Institute of Physics and Engineering (Russia), Siberian Physical-technical Institute (Russia), and Tomsk Polytechnic University (Russia) in September, 7-15, 2015, Belokuriha, Russia. The Symposium provided a high quality of presentations and gathered engineers, scientists, academicians, and young researchers working in the field of rare and rare earth elements mining, modification, separation, elaboration and application, in order to facilitate aggregation and sharing interests and results for a better collaboration and activity visibility. The goal of the REES2015 was to bring researchers and practitioners together to share the latest knowledge on rare and rare earth elements technologies. The Symposium was aimed at presenting new trends in rare and rare earth elements mining, research and separation and recent achievements in advanced materials elaboration and developments for different purposes, as well as strengthening the already existing contacts between manufactures, highly-qualified specialists and young scientists. The topics of the REES2015 were: (1) Problems of extraction and separation of rare and rare earth elements; (2) Methods and approaches to the separation and isolation of rare and rare earth elements with ultra-high purity; (3) Industrial technologies of production and separation of rare and rare earth elements; (4) Economic aspects in technology of rare and rare earth elements; and (5) Rare and rare earth based materials (application in metallurgy, catalysis, medicine, optoelectronics, etc.). We want to thank the Organizing Committee, the Universities and Sponsors supporting the Symposium, and everyone who contributed to the organization of the event and to

  14. A precise 232Th-208Pb chronology of fine-grained monazite: Age of the Bayan Obo REE-Fe-Nb ore deposit, China

    USGS Publications Warehouse

    Wang, Jingyuan; Tatsumoto, M.; Li, X.; Premo, W.R.; Chao, E.C.T.

    1994-01-01

    We have obtained precise Th-Pb internal isochron ages on monazite and bastnaesite for the world's largest known rare earth elements (REE)-Fe-Nb ore deposit, the Bayan Obo of Inner Mongolia, China. The monazite samples, collected from the carbonate-hosted ore zone, contain extremely small amounts of uranium (less than 10 ppm) but up to 0.7% ThO2. Previous estimates of the age of mineralization ranged from 1.8 to 0.255 Ga. Magnetic fractions of monazite and bastnaesite samples (<60-??m size) showed large ranges in 232Th 204Pb values (900-400,000) and provided precise Th-Pb internal isochron ages for paragenetic monazite mineralization ranging from 555 to 398 Ma within a few percent error (0.8% for two samples). These results are the first indication that REE mineralization within the giant Bayan Obo ore deposit occurred over a long period of time. The initial lead isotopic compositions (low 206Pb 204Pb and high 208Pb 204Pb) and large negative ??{lunate}Nd values for Bayan Obo ore minerals indicate that the main source(s) for the ores was the lower crust which was depleted in uranium, but enriched in thorium and light rare earth elements for a long period of time. Zircon from a quartz monzonite, located 50 km south of the ore complex and thought to be related to Caledonian subduction, gave an age of 451 Ma, within the range of monazite ages. Textural relations together with the mineral ages favor an epigenetic rather than a syngenetic origin for the orebodies. REE mineralization started around 555 Ma (disseminated monazite in the West, the Main, and south of the East Orebody), but the main mineralization (banded ores) was related to the Caledonian subduction event ca. 474-400 Ma. ?? 1994.

  15. Tracing the composition and origin of fluids at an ancient hydrocarbon seep (Hollard Mound, Middle Devonian, Morocco): A Nd, REE and stable isotope study

    NASA Astrophysics Data System (ADS)

    Jakubowicz, M.; Dopieralska, J.; Belka, Z.

    2015-05-01

    For the first time, Nd isotope signatures combined with rare earth element (REE) concentrations were used in investigations of ancient seep carbonates. The study was performed on the fossil hydrocarbon seep deposit of the Middle Devonian Hollard Mound (eastern Anti-Atlas, Morocco), where Nd isotopes, REE concentrations, and carbon and oxygen isotope ratios were measured to investigate the origin, former migration pathways and composition of fluids. Relatively high εNd values compared to local Eifelian seawater, as well as consistently appearing positive Eu anomalies in MREE-enriched shale-normalized REE patterns of the seep carbonates provided evidence for interaction between the seeping fluids and the Lower Devonian basaltic volcaniclastics underlying the studied seep deposit. Strongly reducing conditions and increased temperature of methane formation could have constituted an additional factor in the Eu-enrichment of the investigated carbonate phases. The presence of exclusively negative Ce anomalies in these carbonates is in line with observations of other workers that seep limestones may not necessarily display positive Ce anomalies indicative of precipitation under anoxic conditions. The negative Ce anomalies are attributed here to mixing between anoxic pore waters and oxic, Ce-depleted seawater, necessary to enable carbonate precipitation at seeps. The methane-rich fluids ascended most likely from below the volcaniclastic unit and inherited the enriched εNd signatures and positive Eu anomalies due to fluid-rock interactions during their seepage to the seafloor. The carbon isotope data are most consistent with thermogenic origin of methane, although contribution of abiotic and biogenic methane sources cannot be excluded. Our results indicate that neodymium isotope and rare earth element analyses constitute one of the most valuable tools for reconstructing former fluid migration patterns. The study shows also that Nd isotopes and Eu anomalies can serve as

  16. REE distribution in zircon from reference rocks of the Arctic region: Evidence from study by the LA-ICP-MS method

    NASA Astrophysics Data System (ADS)

    Nikolaev, A. I.; Drogobuzhskaya, S. V.; Bayanova, T. B.; Kaulina, T. V.; Lyalina, L. M.; Novikov, A. I.; Steshenko, E. N.

    2016-10-01

    The results of the LA-ICP-MS analysis of the concentrations of REEs, U, Th, and Hf in zircon from Paleo- and Neoarchean reference rocks of the Kola region (garnet-amphibole gneiss, basic and acid granulites, and granite pegmatite) are reported. A new methodology of the study of accessory zircons has been validated and modified. The accuracy of the results is confirmed by analysis of standard zircons Temora 1 and 91 500 and by comparison with the data obtained in other laboratories.

  17. REE Sorption Study on sieved -50 +100 mesh fraction of Media #1 in Brine #1 with Different Starting pH's at 70C

    DOE Data Explorer

    Gary Garland

    2015-09-29

    This is a continuation of the REE sorption study for shaker bath tests on 2g media #1 in 150mL brine #1 with different starting pH's at 70C. In a previous submission we reported data for shaker bath tests for brine #1 with starting pH's of 3.5, 4.5 and 5.5. In this submission we these pH's compared to starting brine #1 pH's of 6, and 7.

  18. Distribution of trace elements including tellurium, gallium, indium, and select REE in sulfide chimneys from Brothers submarine volcano, Kermadec arc

    NASA Astrophysics Data System (ADS)

    Berkenbosch, H. A.; de Ronde, C. E.; McNeill, A.; Goemann, K.; Gemmell, J. B.

    2011-12-01

    -rich chimney also contained native Te in a similar distribution as the tellurides. Whole rock geochemical analysis has determined the maximum concentration of trace elements and REE such as In (53.1 ppm), Ga (1870), Y (26), La (21.2), Ce (21), Sm (2.8), Gd (4), and Yb (3) in Brothers chimneys. To better understand the mineral associations and zonation of these and other trace elements within the chimney walls, we have undertaken element mapping on the four different chimneys types with both X-Ray fluorescence microscopy using synchrotron radiation and with Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS). For example, in a chalcopyrite-rich chimney visibly laminated chalcopyrite in the interior contains bands of Co, Mo, Ag, Te, Au, and Bi, whereas In, La, Ce, Ga, and Y are concentrated in other mineral phases towards the exterior. Element mapping allows us to better understand the physico-chemical gradients within chimney walls, as well as metal sources and transportation, and depositional processes.

  19. Petrography and the REE-composition of apatite in the Paleoproterozoic Pilgujärvi Sedimentary Formation, Pechenga Greenstone Belt, Russia

    NASA Astrophysics Data System (ADS)

    Joosu, Lauri; Lepland, Aivo; Kreitsmann, Timmu; Üpraus, Kärt; Roberts, Nick M. W.; Paiste, Päärn; Martin, Adam P.; Kirsimäe, Kalle

    2016-08-01

    The first globally significant phosphorous-rich deposits appear in the Paleoproterozoic at around 2 Ga, however, the specific triggers leading to apatite precipitation are debated. We examine phosphorous-rich rocks (up to 8 wt% P2O5) in 1.98-1.92 Ga old Pilgujärvi Sedimentary Formation, Pechenga Greenstone Belt, Russia. Phosphates in these rocks occur as locally derived and resedimented sand-to-gravel/pebble sized grains consisting of apatite-cemented muddy sediments. Phosphatic grains can be subdivided into four petrographic types (A-D), each has a distinct REE signature reflecting different early-to-late diagenetic conditions and/or metamorphic overprint. Pyrite containing petrographic type D, which typically has a flat REE pattern, negative Ce anomaly and positive Eu anomaly, is the best preserved of the four types and best records conditions present during apatite precipitation. Type D phosphatic grains precipitated under (sub)oxic basinal conditions with a significant hydrothermal influence. These characteristics are similar to Zaonega Formation phosphates of NW Russia's Onega Basin, and consistent with phosphogenesis triggered by the development of anoxic(sulfidic)-(sub)oxic redoxclines at shallow sediment depth during the Paleoproterozoic.

  20. U, Th, Pb and REE abundances and Pb 207/Pb 206 ages of individual minerals in returned lunar material by ion microprobe mass analysis.

    NASA Technical Reports Server (NTRS)

    Andersen, C. A.; Hinthorne, J. R.

    1972-01-01

    Results of ion microprobe analyses of Apollo 11, 12 and 14 material, showing that U, Th, Pb and REE are concentrated in accessory minerals such as apatite, whitlockite, zircon, baddeleyite, zirkelite, and tranquillityite. Th/U ratios are found to vary by over a factor of 40 in these minerals. K, Ba, Rb and Sr have been localized in a K rich, U and Th poor glass phase that is commonly associated with the U and Th bearing accessory minerals. Li is observed to be fairly evenly distributed between the various accessory phases. The phosphates have been found to have REE abundance patterns (normalized to the chondrite abundances) that are fairly flat, while the Zr bearing minerals have patterns that rise steeply, by factors of ten or more, from La to Gd. All the accessory minerals have large negative Eu anomalies. Radiometric age dates (Pb 207/Pb 206) of the individual U and Th bearing minerals compare favorably with the Pb 207/Pb 206 age of the bulk rocks.

  1. Distribution of U and REE on colloids in granitic groundwater and quality-controlled sampling at the Mizunami underground research laboratory

    NASA Astrophysics Data System (ADS)

    Munemoto, Takashi; Ohmori, Kazuaki; Iwatsuki, Teruki

    2014-12-01

    Colloids and their association with analogue elements, uranium, and rare earth elements (REEs), in deep granitic groundwater were investigated at the Mizunami Underground Research Laboratory (MIU). Groundwater was sampled from underground boreholes and gallery walls, and the colloids were separated by size-fractionated ultrafiltration (pore sizes, 0.2 μm, 10 kDa, and 1 kDa). For the groundwater sampled from fractures in excavation walls, the size-fractionated concentrations of the colloid-forming elements were approximately constant relative to different size fractions (0.2 μm, 200 kDa, 50 kDa, and 10 kDa). The contamination of Fe- and Al-bearing materials was insignificant in the filtered groundwater from fracture seepages. Changes in the concentrations of U in the groundwater sampled from boreholes and excavation walls were associated with the Al-bearing colloids, Fe-bearing colloids, and organic matter. The REE-bearing material(s) that were >0.2 μm in size were mobile in the deep granitic groundwater, rather than occurring in association with Al-bearing, Fe-bearing colloids, and organic matter. It is suggested that sampling from water-conducting fractures in host rock and colloid elimination in borehole are important components of water quality control in geochemical investigations.

  2. Percolation of enriched melts during incremental open-system melting in the spinel field: A REE approach to abyssal peridotites from the Southwest Indian Ridge

    NASA Astrophysics Data System (ADS)

    Brunelli, Daniele; Paganelli, Emanuele; Seyler, Monique

    2014-02-01

    The effects of melting in an open-system scenario are here explored looking to the rare earth element (REE) distribution in mantle residues. We consider a peridotite matrix equilibrated in the spinel field accounting for melt inflow during partial melting. The fertility of the source, inflowing melt composition and melt addition rate as well as the effects of varying the critical mass porosity in an incremental scenario are tested. When a relatively enriched melt enters the system, residual clinopyroxene REE normalized patterns apparently rotate around a light to intermediate REE due to concomitant increase of the light REEs and decrease of the heavy REEs. This effect is enhanced when the critical mass porosity is large with respect to the degree of melting. In these cases the system approaches batch more than fractional melting behaviour because the liquid is preferentially retained in the matrix. This geometry is suggestive of melt accumulation at depth. Four sample suites from the Southwest Indian Ridge are considered. Spinel field equilibrated clinopyroxenes in lherzolites and harzburgites show dredge-scale REE compositional trends that crosscut model fractional melting trajectories. Observed local trends correspond to rotations of the REE patterns attesting for near-batch episodes in the subridge melting history and infiltration of enriched liquids whose composition resemble that of garnet field-generated melts. C0: starting source composition. D0: starting bulk partition coefficient. P: bulk partition coefficient weighted for the mineral melting mode (modal melting for P = D). Ca: is the tracer concentration in the inflowing melt. The composition of the liquid produced during non-modal melting is estimated by using equation (30) of Shaw (2000): {C}/{C}={C}/{0lC}-{β}/{(1+β)(1-P)}{C}/{C}1+{β}/{(1+β)(1-P)}{Ca}/{C0} The composition of the solid in equilibrium with the liquid is Cs = DCL, where D is the bulk partition coefficient for a given element

  3. Geology and genesis of the Toongi rare metal (Zr, Hf, Nb, Ta, Y and REE) deposit, NSW, Australia, and implications for rare metal mineralization in peralkaline igneous rocks

    NASA Astrophysics Data System (ADS)

    Spandler, Carl; Morris, Caitlin

    2016-12-01

    The Toongi Deposit, located in central NSW, Australia, hosts significant resources of Zr, Hf, Nb, Ta, Y and REE within a small (ca. 0.3 km2), rapidly cooled trachyte laccolith. Toongi is part of regional Late Triassic to Jurassic alkaline magmatic field, but is distinguished from the other igneous bodies by its peralkaline composition and economically significant rare metal content that is homogenously distributed throughout the trachyte body. The primary ore minerals are evenly dispersed throughout the rock and include lueshite/natroniobite and complex Na-Fe-Zr-Nb-Y-REE silicate minerals dominated by a eudialyte group mineral (EGM). The EGM occurs in a unique textural setting in the rock, commonly forming spheroidal or irregular-shaped globules, herein called "snowballs", within the rock matrix. The snowballs are often protruded by aegirine and feldspar phenocrysts and contain swarms of fine aegirine and feldspar grains that often form spiral or swirling patterns within the snowball. Secondary ore minerals include REE carbonates, Y milarite, catapleiite and gaidonnayite that fill fractures and vesicles in the rock. Based on bulk-rock geochemical and Nd isotope data, and thermodynamic modelling of magma fractionation, the alkaline rocks of the region are interpreted to represent extrusive to hyperbyssal products of mantle-derived magma that ponded at mid-crustal levels (ca. 0.3 GPa) and underwent extensive fractionation under low-oxygen fugacity conditions. The high Na2O, peralkaline nature of the Toongi Deposit trachyte developed via extensive fractionation of an alkali olivine basalt parental magma initially in the mid-crust and subsequently at shallow levels (ca. 0.1 GPa). This extended fractionation under low fO2 and relatively low H2O-activity conditions limited volatile release and allowed build-up of rare metal contents to ore grades. We speculate that the ore minerals may have originally formed from rare metal-rich sodic-silicate melt that formed immiscible

  4. Stages of weathering mantle formation from carbonate rocks in the light of rare earth elements (REE) and Sr-Nd-Pb isotopes

    NASA Astrophysics Data System (ADS)

    Hissler, Christophe; Stille, Peter

    2015-04-01

    Weathering mantles are widespread and include lateritic, sandy and kaolinite-rich saprolites and residuals of partially dissolved rocks. These old regolith systems have a complex history of formation and may present a polycyclic evolution due to successive geological and pedogenetic processes that affected the profile. Until now, only few studies highlighted the unusual high content of associated trace elements in weathering mantles originating from carbonate rocks, which have been poorly studied, compared to those developing on magmatic bedrocks. For instance, these enrichments can be up to five times the content of the underlying carbonate rocks. However, these studies also showed that the carbonate bedrock content only partially explains the soil enrichment for all the considered major and trace elements. Up to now, neither soil, nor saprolite formation has to our knowledge been geochemically elucidated. Therefore, the aim of this study was to examine more closely the soil forming dynamics and the relationship of the chemical soil composition to potential sources. REE distribution patterns and Sr-Nd-Pb isotope ratios have been used because they are particularly well suited to identify trace element migration, to recognize origin and mixing processes and, in addition, to decipher possible anthropogenic and/or "natural" atmosphere-derived contributions to the soil. Moreover, leaching experiments have been applied to identify mobile phases in the soil system and to yield information on the stability of trace elements and especially on their behaviour in these Fe-enriched carbonate systems. All these geochemical informations indicate that the cambisol developing on such a typical weathering mantle ("terra fusca") has been formed through weathering of a condensed Bajocian limestone-marl facies. This facies shows compared to average world carbonates important trace element enrichments. Their trace element distribution patterns are similar to those of the soil

  5. Standardless EDXRF application for quantification of thorium (Th), uranium (U) and rare earth elements (REEs) in various Malaysian rare earth ores

    NASA Astrophysics Data System (ADS)

    Ruf, Mohd Izzat Fahmi Mohd; Bahri, Che Nor Aniza Che Zainul; AL-Areqi, Wadeeah M.; Majid, Amran Ab.

    2016-11-01

    Our local rare earth ores contained substantial amount of Thorium and Uranium which the level exceed permissible limit adopted by Malaysia and many importing nation. X-ray fluorescence technique has been applied for determination of thorium (Th), uranium (U) and rare earth elements (REEs) in Malaysian rare earth ores as it's recognized as viable tool. XRF has been widely used in detecting elemental composition of unknown materials both qualitative and quantitatively because of its wide range of element detection alongside the non-destructive analytical technique with great accuracy and precision. Four types of minerals sample which is monazite, xenotime, ilmenite and zircon were collected from `amang' factory located in famous city of mining, Ipoh and analyzed using EDXRF.

  6. Structural controls and evolution of gold-, silver-, and REE-bearing copper-cobalt ore deposits, Blackbird district, east-central Idaho: Epigenetic origins

    USGS Publications Warehouse

    Lund, K.; Tysdal, R.G.; Evans, K.V.; Kunk, M.J.; Pillers, R.M.

    2011-01-01

    Textural data at all scales indicate that the host sites for veins and the tectonic evolution of both host rocks and mineral deposits were kinematically linked to Late Cretaceous regional thrust faulting. Heat, fluids, and conduits for generation and circulation of fluids were part of the regional crustal thickening. The faulting also juxtaposed metaevaporite layers in the Mesoproterozoic Yellowjacket Formation over Blackbird district host rocks. We conclude that this facilitated chemical exchange between juxtaposed units resulting in leaching of critical elements (Cl, K, B, Na) from metaevaporites to produce brines, scavenging of metals (Co, Cu, etc) from rocks in the region, and, finally, concentrating metals in the lower-plate ramp structures. Although the ultimate source of the metals remains undetermined, the present Cu-Co ± Au (± Ag ± Ni ± REE) Blackbird ore deposits formed during Late Cretaceous compressional deformation.

  7. An ion microprobe study of the intra-crystalline behavior of REE and selected trace elements in pyroxene from mare basalts with different cooling and crystallization histories

    NASA Technical Reports Server (NTRS)

    Shearer, C. K.; Papike, J. J.; Simon, S. B.; Shimizu, N.

    1989-01-01

    The effects of crystallization interaction on the trace element zoning characteristics of pyroxenes are analyzed using electron and ion microprobe techniques. Four pigeonite basalts with similar isochemical composition, but different cooling rates and crystallization histories are studied. Pyroxene quadrilaterals displaying crystallization trends are presented. The crystal chemical rationalization of REE zoning, pattern shapes, and abundances are examined. The data reveal that the trace element zoning characteristics in pyroxene and the partitioning of trace elements between pyroxene and the melt are related to the interaction between the efficiency of the crystallization process, the kinetics at the crystal-melt interface, the kinetics of plagioclase nucleation and the characteristics of the crystal chemical substitutions in the pyroxene and the associated crystallizing phase.

  8. An introduction of Markov chain Monte Carlo method to geochemical inverse problems: Reading melting parameters from REE abundances in abyssal peridotites

    NASA Astrophysics Data System (ADS)

    Liu, Boda; Liang, Yan

    2017-04-01

    Markov chain Monte Carlo (MCMC) simulation is a powerful statistical method in solving inverse problems that arise from a wide range of applications. In Earth sciences applications of MCMC simulations are primarily in the field of geophysics. The purpose of this study is to introduce MCMC methods to geochemical inverse problems related to trace element fractionation during mantle melting. MCMC methods have several advantages over least squares methods in deciphering melting processes from trace element abundances in basalts and mantle rocks. Here we use an MCMC method to invert for extent of melting, fraction of melt present during melting, and extent of chemical disequilibrium between the melt and residual solid from REE abundances in clinopyroxene in abyssal peridotites from Mid-Atlantic Ridge, Central Indian Ridge, Southwest Indian Ridge, Lena Trough, and American-Antarctic Ridge. We consider two melting models: one with exact analytical solution and the other without. We solve the latter numerically in a chain of melting models according to the Metropolis-Hastings algorithm. The probability distribution of inverted melting parameters depends on assumptions of the physical model, knowledge of mantle source composition, and constraints from the REE data. Results from MCMC inversion are consistent with and provide more reliable uncertainty estimates than results based on nonlinear least squares inversion. We show that chemical disequilibrium is likely to play an important role in fractionating LREE in residual peridotites during partial melting beneath mid-ocean ridge spreading centers. MCMC simulation is well suited for more complicated but physically more realistic melting problems that do not have analytical solutions.

  9. Reconstruction of Sothern Ocean dust fluxes and dust provenance areas at highest spatial resolution: implications from 230Thxs, isotopic and REE data

    NASA Astrophysics Data System (ADS)

    Wengler, M.; Lamy, F.; Geibert, W.; Pahnke, K.; Kuhn, G.; Gersonde, R.; Tiedemann, R.

    2015-12-01

    The study of dust fluxes in the Southern Ocean (SO) is crucial to understand processes and feedback mechanisms in the SO since atmospheric dust is considered to play a key role in past atmospheric CO2 variability by affecting the marine biological production through iron fertilization. We present 230Thxs, isotopic (Sr, Nd, Pb) and REE data of numerous surface samples across the Pacific sector of the SO in order to determine lithogenic mass accumulation rates (MAR) (corrected for sediment focusing) and possible dust provenance areas. Our MAR data display highest values near New Zealand´s east coast (South Island), however this may not reflect a pure Australian/New Zealand dust signal due to a strong influence of fluvial sediment input from New Zealand sources. In contrast, we interpret the open ocean MAR values as derived from the Australian/New Zealand dust plume, which might reach as far east as ~100° W. The highest MAR values among the open ocean samples are found south of the winter sea ice front (WSI), and likely reflect the admixture of ice rafted debris (IRD). Further east of ~100° W, the MAR data exceed the open ocean samples by up to a factor of ~6, consistent with predominating terrigenous input from southernmost Patagonia and Antarctica. Combining the MAR data set with provenance sensitive proxies (isotopic and REE data) enables us to identify at least 3 different possible provenance areas (Australia/New Zealand, Antarctica and Patagonia) and to reconstruct the possible pathway of the Australian/New Zealand dust plume. Since the atmospheric circulation (westerly winds) is one controlling factor influencing the distribution of dust over the SO this data set also allows us to infer variations of wind speed and strength of the westerly wind belt.

  10. Pt-Re-Os and Sm-Nd isotope and HSE and REE systematics of the 2.7 Ga Belingwe and Abitibi komatiites

    NASA Astrophysics Data System (ADS)

    Puchtel, I. S.; Walker, R. J.; Brandon, A. D.; Nisbet, E. G.

    2009-10-01

    High-precision Pt-Re-Os and Sm-Nd isotope and highly siderophile element (HSE) and rare earth element (REE) abundance data are reported for two 2.7 b.y. old komatiite lava flows, Tony's flow (TN) from the Belingwe greenstone belt, Zimbabwe, and the PH-II flow (PH) from Munro Township in the Abitibi greenstone belt, Canada. The emplaced lavas are calculated to have contained ˜25% (TN) and ˜28% (PH) MgO. These lavas were derived from mantle sources characterized by strong depletions in highly incompatible lithophile trace elements, such as light REE (Ce/Sm N = 0.64 ± 0.02 (TN) and 0.52 ± 0.01 (PH), ɛ 143Nd(T) = +2.9 ± 0.2 in both sources). 190Pt- 186Os and 187Re- 187Os isochrons generated for each flow yield ages consistent with respective emplacement ages obtained using other chronometers. The calculated precise initial 186Os/ 188Os = 0.1198318 ± 3 (TN) and 0.1198316 ± 5 (PH) and 187Os/ 188Os = 0.10875 ± 17 (TN) and 0.10873 ± 15 (PH) require time-integrated 190Pt/ 188Os and 187Re/ 188Os of 0.00178 ± 11 and 0.407 ± 8 (TN) and 0.00174 ± 18 and 0.415 ± 5 (PH). These parameters, which by far represent the most precise and accurate estimates of time-integrated Pt/Os and Re/Os of the Archean mantle, are best matched by those of enstatite chondrites. The data also provide evidence for a remarkable similarity in the composition of the sources of these komatiites with respect to both REE and HSE. The calculated absolute HSE abundances in the TN and PH komatiite sources are within or slightly below the range of estimates for the terrestrial Primitive Upper Mantle (PUM). Assuming a chondritic composition of the bulk silicate Earth, the strong depletions in LREE, yet chondritic Re/Os in the komatiite sources are apparently problematic because early Earth processes capable of fractionating the LREE might also be expected to fractionate Re/Os. This apparent discrepancy could be reconciled via a two-stage model, whereby the moderate LREE depletion in the sources of

  11. Analysis of Rare Earth Elements (REE) in vein quartz and quartz-sandstone host rock in the Zhelannoe high purity quartz deposit, Russia

    NASA Astrophysics Data System (ADS)

    Zemskova, Marina; Prokofiev, Vsevolod; Bychkov, Andrey

    2015-04-01

    The Zhelannoe high purity quartz deposit is located on the western slope of the Polar Urals. It is one of the largest deposits of vein quartz and rock crystal in Russia. Most of the mineralization is hosted within a single horizon of very firm quartz-sandstone, where plastic deformation did not occur almost entirely. All tectonic stress was released by the development of numerous thrust faults of different scales. Cavities formed during this process were later filled with quartz and rock crystal. In order to obtain more details on conditions under which mineralization took place, analysis of trace element contents in vein quartz and host rocks, and the micro-thermometric study of fluid inclusions in quartz have been carried out. The trace element composition of vein quartz and of the host rock has been determined by ICP-MS. The results have shown that concentrations of most of the 46 studied elements in quartz are two orders of magnitude lower than in chondrite, and more than three orders of magnitude lower than in the upper crust. Even though Pb and Li have the highest concentrations in quartz samples, levels are only nearly comparable in chondrite, and substantially lower in the upper crust. At the same time, negative anomalies of Pb and Li concentrations in the host rock may indicate the removal of these elements during vein quartz formation. Contents of most REEs are two orders of magnitude lower than in chondrite, and three orders of magnitude lower than in the host rock. Generally, the patterns of REE distribution in vein quartz and the host rock express a clear correlation; confirming the genetic link between vein quartz and quartz-sandstone host rock. However, the process of quartz recrystallization led to an intense decrease of REEs content, and of all other impurities, which consequently influenced industrial value of the Zhelannoe deposit. As a result of the micro-thermometric study of fluid inclusions in quartz, the following physical

  12. REE signatures in 3.51 Ga BIF and Bedded Chert from Iron Ore Group, Singhbhum Craton, India: Implications for Paleoarchean Ocean Oxygenation

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, J.; Ghosh, G.

    2013-12-01

    The metasedimentary rock records in Archaean greenmstone belts provide primary information on evolution of the early Earth. The bedded cherts and BIFs in particular have been studied from Paleo-Mesoarchean greenstone belts for understanding the nature of the oceanic circulation and for the record of early life. However, scarcity of low-strained Paleo-Mesoarchean successions is a major impediment in this regard. The southern Iron Ore Group (SIOG) (3506.8 × 2.3 Ma, U-Pb SHRIMP on zircon by Mukhopadhyay et al., 2008) of the Singhbhum Craton, eastern India includes low-grade bimodal volcanics-ultramafics and BIF -bearing greenstone succession. The bedded chert and BIFs in this succession show significant stratigraphic variation that suggests a stratified ocean and availability of dissolved oxygen in deep-water regime. Bedded chert occurs interleaved with either metabasics or with the silicic volcanics in the lower part of the succession. BIF occurs only towards the top of the succession conformably overlying the silicic volcanics. The bedded cherts with REE and other trace element compositions such as Cu, Co, Ni, Zr, Hf pointing towards contributions from terrigenous or silicic as well as mafic volcanic sources. In contrast BIFs with very low alumina content and superchondritic Y/Ho ratios (36.2 to 40.1) indicate negligible inputs from terrigenous source and is comparable to cherts from Cenozoic ridges. REE-compositions of the bedded chert with respect to PAAS show a flat pattern with feeble positive Eu-anomaly and negligible negative Ce-anomaly. The REE patterns in BIF though similar but show much stronger positive Eu-anomaly and negative Ce-anomaly in comparison. Stratigraphic trend in the geochemical proxies from bedded cherts to BIF, thus record a relative increase in positive Eu-anomaly and decrease in Ce-anomaly. The increase in Eu-anomaly coincident with the BIF deposition up section is likely to suggest increase in in hydrothermal input and ridge spreading

  13. Ocean circulation and freshwater pathways in the Arctic Mediterranean based on a combined Nd isotope, REE and oxygen isotope section across Fram Strait

    NASA Astrophysics Data System (ADS)

    Laukert, Georgi; Frank, Martin; Bauch, Dorothea; Hathorne, Ed C.; Rabe, Benjamin; von Appen, Wilken-Jon; Wegner, Carolyn; Zieringer, Moritz; Kassens, Heidemarie

    2017-04-01

    The water masses passing the Fram Strait are mainly responsible for the exchange of heat and freshwater between the Nordic Seas and the Arctic Ocean (the Arctic Mediterranean, AM). Disentangling their exact sources, distribution and mixing, however, is complex. This work provides new insights based on a detailed geochemical tracer inventory including dissolved Nd isotope (εNd), rare earth element (REE) and stable oxygen isotope (δ18O) data along a full water depth section across Fram Strait. We find that Nd isotope and REE distributions in the open AM primarily reflect lateral advection of water masses and their mixing. Seawater-particle interactions exert important control only above the shelf regions, as observed above the NE Greenland Shelf. Advection of northward flowing warm Atlantic Water (AW) is clearly reflected by an εNd signature of -11.7 and a Nd concentration ([Nd]) of 16 pmol/kg in the upper ∼500 m of the eastern and central Fram Strait. Freshening and cooling of the AW on its way trough the AM are accompanied by a continuous change towards more radiogenic εNd signatures (e.g. -10.4 of dense Arctic Atlantic Water). This mainly reflects mixing with intermediate waters but also admixture of dense Kara Sea waters and Pacific-derived waters. The more radiogenic εNd signatures of the intermediate and deep waters (reaching -9.5) are mainly acquired in the SW Nordic Seas through exchange with basaltic formations of Iceland and CE Greenland. Inputs of Nd from Svalbard are not observed and surface waters and Nd on the Svalbard shelf originate from the Barents Sea. Shallow southward flowing Arctic-derived waters (<200 m) form the core of the East Greenland Current above the Greenland slope and can be traced by their relatively radiogenic εNd (reaching -8.8) and elevated [Nd] (21-29 pmol/kg). These properties are used together with δ18O and standard hydrographic tracers to define the proportions of Pacific-derived (<∼30% based on Nd isotopes) and

  14. An assessment of a handheld X-ray fluorescence instrument for use in exploration and development with an emphasis on REEs and related specialty metals

    NASA Astrophysics Data System (ADS)

    Simandl, G. J.; Stone, R. S.; Paradis, S.; Fajber, R.; Reid, H. M.; Grattan, K.

    2014-12-01

    Handheld (portable) X-ray fluorescence (pXRF) instruments are designed for use in the exploration for base metals, precious metals, and specialty metals (e.g. rare earth elements (REE), Ta, and Nb) and allow rapid decision-making directly in the field. This paper evaluates the technical merits and limitations of pXRF technology in the exploration for specialty metals using data generated from the analysis of three geochemical standards and a silica blank: Standard Reference Material NIST 2780 from the National Institute of Standards and Technology, Gaithersburg; the Certified Reference Material "TRLK" Rare Earth Ore "CGL 124" from the Mongolia Central Geological Laboratory; the Reference Niobium Ore OKA-1 (CANMET); and a silica blank described as Si (IV) oxide (99.8 % on metal basis) from Alpha Aesar (Ward Hill, MA, USA). The data was acquired over a period of nearly 2 years as a by-product of several distinct specialty metal-related projects using the same pXRF instrument and the same settings. Instrumental analytical accuracy was determined using the percent difference (%diff) between the average concentrations of the pXRF instrument readings and the reported certified values of the standard. Percent relative standard deviation (%RSD) was used as a measure of precision. Smaller %diff and %RSD indicate more accurate and precise data, and the accuracy and precision of the pXRF depended strongly on the elemental concentrations in the standards used. Box and whisker diagrams were used to illustrate characteristics of pXRF data sets (mean, lower and upper quartiles, and range) corresponding to individual standards. The bias of the pXRF determinations (under/overestimation) relative to certified values of individual standards are also depicted on these diagrams. This study indicates that the pXRF was capable of producing readings for Si, K, Al, Fe, Ca, Ti, Pb, Zn, Sr, Ag, Cd, Th, Sb, P, S, Mo, Mn, Mg, As, Nb, Rb, La, Ce, Pr, Nd, and Y within 10 %RSD of the reported

  15. Experimental determination of REE fractionation between liquid and vapour in the systems NaCl-H2O and CaCl2-H2O up to 450 °C

    NASA Astrophysics Data System (ADS)

    Shmulovich, Kirill; Heinrich, Wilhelm; Möller, Peter; Dulski, Peter

    2002-09-01

    Fractionation of selected REE between brine and vapour was experimentally determined using a large-volume rocking Ti-autoclave that allowed quasi-isobaric sampling of liquid-vapour pairs. Samples were extracted along the 350, 400 and 450 °C-isotherms of the H2O-NaCl system, and along the 400 °C isotherm of the CaCl2 system. Total salt concentrations were either 6.6 and 10 wt% NaCl or CaCl2, respectively, and total REE concentrations were about 2 ppm of each REE. Starting pH at room temperature was 1.8, added as HCl. In another series of experiments, REEs were added in amounts of 312 ppm. Here, the starting pH at room temperature was 0.5, added as HNO3:HCl=1:2. Liquid-vapour pairs (L-V) were analysed for REE by ICP-MS methods. L-V-partitioning of REE along a particular isotherm follows broadly the partitioning of the main salt components, NaCl or CaCl2. DREE=REEV/REEL decrease rapidly from the critical point with decreasing pressure (equivalent to increasing salinity of the liquid) as the solvus opens. This is independent of the total amount of the added REE. Log DREE values show approximately linear correlations with decreasing pressure from the critical point to salt-saturated conditions where the L-V curve meets the liquid + vapour + solid boundary. At given P and T, we found a systematic variation of DREE along the La-Lu suite. HREE are enriched in the vapour phase relative to LREE. Fractionation coefficients KD=(HREEV/HREEL)/(LREEV/LREEL) increase linearly with ΔP=Pcrit-P along a particular isotherm. At the 450 °C isotherm, KD (Lu/La) at the critical point (425 bar and 10 wt% NaCl) is 1; about 2.5 at 350 bar (33 wt% NaCl in the liquid); and about 5 if extrapolated to salt-saturation (250 bar and 52 wt% NaCl in the liquid). The REE fractionation behaviour is similar along the CaCl2-H2O solvus boundaries. Existing equations of state and thermodynamic databases of REE species cannot predict this behaviour at L-V-equilibrium conditions. That HREE are

  16. Major, trace and REE geochemistry in contrasted chlorite schist weathering profiles from southern Cameroon: Influence of the Nyong and Dja Rivers water table fluctuations in geochemical evolution processes

    NASA Astrophysics Data System (ADS)

    Onana, Vincent Laurent; Ntouala, Roger Firmin Donald; Tang, Sylvie Noa; Effoudou, Estelle Ndome; Kamgang, Veronique Kabeyene; Ekodeck, Georges Emmanuel

    2016-12-01

    Three weathering profiles developed on chlorite schists, formations on which little studies have been conducted, were chosen to understand the weathering processes prevailing downslope in Southern Cameroon. The materials nearest to Nyong River at Ayos weather under the influence of the fluctuations of groundwater table and acid rain, while those from Bengbis and Mbalmayo weather under the influence of acid rain. The result is the thickening of materials and weathering profiles, without formation of a nodular ferruginous horizon at Ayos. The Ayos weathered materials (CIA ∼ 92) are the most altered and the least lateritised (IOL ∼ 32). The most stable systems are Hf - U - Nb - Ti - Zr - Mo - W (Bengbis), Yb - U - Nb - Ti - Zr - Hf - Mo - W - Th (Mbalmayo) and Th - Nb - Zr - Hf - Mo - Ta (Ayos). Molybdenum accumulations are important in the studied materials. Uranium accumulations are found only in Mbalmayo. Coarse saprolitic materials at Ayos are the most depleted and fractionated in REE ((La/Yb)N = 0.07, Ce/Ce* = 2.24), while superficial clayey materials are less fractionated. This process is reversed at Bengbis and Mbalmayo. By contrast, weathered materials at Ayos do not show any Eu anomalies (as in Bengbis and Mbalmayo). Weathered materials from Bengbis, nearest to the Dja River, have (La/Yb)N < 1 ratios, indicating the relative immobility of HREE relative to LREE due to xenotime abnormally rich in HREE (HREE-PO4). Weak Ce anomalies (1.05-2.24) are ubiquitous in all the studied materials.

  17. Detrital zircon U-Pb geochronology, Lu-Hf isotopes and REE geochemistry constrains on the provenance and tectonic setting of Indochina Block in the Paleozoic

    NASA Astrophysics Data System (ADS)

    Wang, Ce; Liang, Xinquan; Foster, David A.; Fu, Jiangang; Jiang, Ying; Dong, Chaoge; Zhou, Yun; Wen, Shunv; Van Quynh, Phan

    2016-05-01

    In situ U-Pb geochronology, Lu-Hf isotopes and REE geochemical analyses of detrital zircons from Cambrian-Devonian sandstones in the Truong Son Belt, central Vietnam, are used to provide the information of provenance and tectonic evolution of the Indochina Block. The combined detrital zircon age spectra of all of the samples ranges from 3699 Ma to 443 Ma and shows with dominant age peaks at ca. 445 Ma and 964 Ma, along with a number of age populations at 618-532 Ma, 1160-1076 Ma, 1454 Ma, 1728 Ma and 2516 Ma. The zircon age populations are similar to those from time equivalent sedimentary sequences in continental blocks disintegrated from the East Gondwana during the Phanerozoic. The younger zircon grains with age peaks at ca. 445 Ma were apparently derived from middle Ordovician-Silurian igneous and metamorphic rocks in Indochina. Zircons with ages older than about 600 Ma were derived from other Gondwana terrains or recycled from the Precambrian basement of the Indochina Block. Similarities in the detrital zircon U-Pb ages suggest that Paleozoic strata in the Indochina, Yangtze, Cathaysia and Tethyan Himalayas has similar provenance. This is consistent with other geological constrains indicating that the Indochina Block was located close to Tethyan Himalaya, northern margin of the India, and northwestern Australia in Gondwana.

  18. Iron isotope and REE+Y composition of the Cauê banded iron formation and related iron ores of the Quadrilátero Ferrífero, Brazil

    NASA Astrophysics Data System (ADS)

    Mendes, Mônica; Lobato, Lydia M.; Kunzmann, Marcus; Halverson, Galen P.; Rosière, Carlos A.

    2017-02-01

    The Minas Supergroup banded iron formations (BIFs) of the Brazilian Quadrilátero Ferrífero (QF) mineral province experienced multiple deformational events synchronous with hypogene mineralization, which resulted in the metamorphism of BIFs to itabirites and their upgrade to high-grade iron ore. Here, we present rare earth element and yttrium (REE+Y) compositions together with iron isotope ratios of itabirites and their host iron orebodies from 10 iron deposits to constrain environmental conditions during BIF deposition and the effects of hypogene iron enrichment. The REE+Y characteristics of itabirites (positive Eu anomaly and LREE depletion) indicate hydrothermal iron contribution to the Minas basin. Iron isotope data and Ce anomalies suggest BIFs were precipitated by a combination of anoxic biological-mediated ferrous iron oxidation and abiotic oxidation in an environment with free oxygen (such as an oxygen oasis), perhaps related to increase in oxygen concentrations before the Great Oxidation Event (GOE). The similarity of the REE+Y composition of the itabirites from the different QF deformational domains, as well as to other Superior-type BIFs, indicates that the metamorphism and synchronous hydrothermal mineralization did not significantly affect the geochemical signature of the original BIFs. However, iron isotope compositions of iron ore vary systematically between deformational domains of the QF, likely reflecting the specific mineralization features in each domain.

  19. Iron isotope and REE+Y composition of the Cauê banded iron formation and related iron ores of the Quadrilátero Ferrífero, Brazil

    NASA Astrophysics Data System (ADS)

    Mendes, Mônica; Lobato, Lydia M.; Kunzmann, Marcus; Halverson, Galen P.; Rosière, Carlos A.

    2016-04-01

    The Minas Supergroup banded iron formations (BIFs) of the Brazilian Quadrilátero Ferrífero (QF) mineral province experienced multiple deformational events synchronous with hypogene mineralization, which resulted in the metamorphism of BIFs to itabirites and their upgrade to high-grade iron ore. Here, we present rare earth element and yttrium (REE+Y) compositions together with iron isotope ratios of itabirites and their host iron orebodies from 10 iron deposits to constrain environmental conditions during BIF deposition and the effects of hypogene iron enrichment. The REE+Y characteristics of itabirites (positive Eu anomaly and LREE depletion) indicate hydrothermal iron contribution to the Minas basin. Iron isotope data and Ce anomalies suggest BIFs were precipitated by a combination of anoxic biological-mediated ferrous iron oxidation and abiotic oxidation in an environment with free oxygen (such as an oxygen oasis), perhaps related to increase in oxygen concentrations before the Great Oxidation Event (GOE). The similarity of the REE+Y composition of the itabirites from the different QF deformational domains, as well as to other Superior-type BIFs, indicates that the metamorphism and synchronous hydrothermal mineralization did not significantly affect the geochemical signature of the original BIFs. However, iron isotope compositions of iron ore vary systematically between deformational domains of the QF, likely reflecting the specific mineralization features in each domain.

  20. Fluorescein Dye Penetration in Round Top Rhyolite (Hudspeth County, Texas, USA) to Reveal Micro-permeability and Optimize Grain Size for Heavy REE Heap Leach

    NASA Astrophysics Data System (ADS)

    Negron, L. M.; Clague, J. W.; Gorski, D.; Amaya, M. A.; Pingitore, N. E.

    2013-12-01

    Millimeter- and micrometer-scale permeability of fine-grained igneous rocks has generated limited research interest. Nonetheless, the scale and distribution of such micro-permeability determines fluid penetration and pathways, parameters that define both the ability to heap leach a rock and the optimal grain size for such an operation. Texas Rare Earth Resources is evaluating the possibility of heap leaching of yttrium and heavy rare earth elements (YHREE) from the peraluminous rhyolite laccolith that forms one-mile-diameter Round Top Mountain. The YHREEs in this immense, surface-exposed deposit (minimum 1.6 billion tons, Texas Bureau Economic Geology) are dilute and diffuse, suggesting leaching as the best option for recovery. The REE grade is 0.05% and YHREEs comprise more than 70% of the total REE content. The YHREEs are hosted exclusively in micron-scale yttrofluorite grains, which proved soluble in dilute sulfuric acid. Laboratory experiments showed YHREE recoveries of up to 90%. Within limits, recoveries decrease with larger grain sizes, and increase with acid strength and exposure time. Our research question centers on dissolution effectiveness: Is YHREE recovery, relative to grain size, limited by (1) diffusion time of acid into, and dissolved solids, including YHREEs, out of the micro-permeability paths inherent in the rock particles; (2) the effective lengths of the natural micro-permeability paths in the rock; or (3) the putative role of the acid in dissolving new micro-paths into the grains? The maximum grain size should not exceed twice the typical path length (unless acid creates new paths), lest YHREEs in the core of a larger grain than that not be reached by acid. If instead diffusion time is limiting, longer leach time may prove effective. Rather than perform an extensive and expensive series of laboratory leaching experiments--some of which would be several months in duration--to determine optimal grain size, we developed a technique to

  1. Multistage hydrothermal silicification and Fe-Tl-As-Sb-Ge-REE enrichment in the Red Dog Zn-Pb-Ag district, northern Alaska: Geochemistry, origin, and exploration applications

    USGS Publications Warehouse

    Slack, J.F.; Kelley, K.D.; Anderson, V.M.; Clark, J.L.; Ayuso, R.A.

    2004-01-01

    Geochemical analyses of major, trace, and rare earth elements (REE) in more than 200 samples of variably silicified and altered wall rocks, massive and banded sulfide, silica rock, and sulfide-rich and unmineralized barite were obtained from the Main, Aqqaluk, and Anarraaq deposits in the Red Dog Zn-Pb-Ag district of northern Alaska. Detailed lithogeochemical profiles for two drill cores at Aqqaluk display an antithetic relationship between SiO2/Al2O3 and TiO2/Zr which, together with textural information, suggest preferential silicification of carbonate-bearing sediments. Data for both drill cores also show generally high Tl, Sb, As, and Ge and uniformly positive Eu anomalies (Eu/Eu* > 1.0). Similar high Tl, Sb, As, Ge, and Eu/Eu* values are present in the footwall and shallow hanging wall of Zn-Pb-Ag sulfide intervals at Anarraaq but are not as widely dispersed. Net chemical changes for altered wall rocks in the district, on the basis of average Al-normalized data relative to unaltered black shales of the host Kuna Formation, include large enrichments (>50%) of Fe, Ba, Eu, V, S, Co, Zn, Pb, Tl, As, Sb, and Ge at both Red Dog and Anarraaq, Si at Red Dog, and Sr, U, and Se at Anarraaq. Large depletions (>50%) are evident for Ca at both Red Dog and Anarraaq, for Mg, P, and Y at Red Dog, and for Na at Anarraaq. At both Red Dog and Anarraaq, wall-rock alteration removed calcite and minor dolomite during hydrothermal decarbonation reactions and introduced Si, Eu, and Ge during silicification. Sulfidation reactions deposited Fe, S, Co, Zn, Pb, Tl, As, and Sb; barite mineralization introduced Ba, S, and Sr. Light REE and U were mobilized locally. This alteration and mineralization occurred during Mississippi an hydrothermal events that predated the Middle Jurassic-Cretaceous Brookian orogeny. Early hydrothermal silicification at Red Dog took place prior to or during massive sulfide mineralization, on the basis of the dominantly planar nature of Zn-Pb veins, which suggests

  2. Efremovka 101.1: A Primitive CAI with Superrefractory REE Patterns and Enormous Enrichments of Sc, Zr, and Y in Fassaite and Perovskite

    NASA Astrophysics Data System (ADS)

    El Goresy, A.; Zinner, E. K.; Matsunami, S.; Palme, H.; Spettel, B.; Lin, Y.; Nazarov, M.

    1993-07-01

    encountered inside the sinuous fragments and in the diopside-anorthite rim sequence of one of the captured CAIs. The texture is strongly suggestive of the reduction of andradite to wollastonite+Fe^degree (via Fe3O4 and FeO). We consider this texture as evidence that andradite was formed in an oxidizing solar gas before capture of the sinuous inclusions by the host CAI and that andradite reduction took place after capture in the highly reduced host CAI refractory liquid. REE concentrations in various minerals reveal a distinct superrefractory pattern with depletions in Tm and Yb. Zr, Y, and Sc abundances of individual phases in the CAI core are indicative of crystal-liquid fractionation during crystallization: fassaite is relatively depleted in Y and enriched in Sc and Zr. In contrast, perovskite displays a complimentary abundance pattern for these elements. The individual mineral layers of the captured CAIs, sinuous fragments, and the rim sequence of the host CAI have similar superrefractory REE patterns but do not show fractionation between Sc, Y, and Zr. This indicates that the rim sequences did not crystallize from the same liquid of the CAI, but condensed from a common gas reservoir with a distinct superrefractory REE signature. Melilite contains excess ^26Mg* with an inferred initial ^26Al/^27Al ratio of (4.4 x 10^-5). However, the Mg-Al system in the anorthites of the captured sinuous fragments and the rim layers of the small CAIs is disturbed. This strongly suggests that oxidation and alteration processes took place in the earliest stage of the solar system.

  3. Post-magmatic solid solutions of CaCeAl2(Fe3+ 2/3□1/3)[Si2O7][SiO4]O(OH), allanite-(Ce) and REE-bearing epidote in miarolitic pegmatites of Permian Baveno granite (Verbania, central-southern alps, Italy)

    NASA Astrophysics Data System (ADS)

    Guastoni, Alessandro; Nestola, Fabrizio; Schiazza, Mariangela

    2016-09-01

    CaCeAl2(Fe3+ 2/3□1/3)[Si2O7][SiO4]O(OH), allanite-(Ce) and rare earth element (REE)-bearing epidote occur as globular aggregates and platy prismatic crystals in miarolitic cavities in a niobium, yttrium, fluorine (NYF) granitic pegmatite at Baveno, Verbania, Southern Alps, Italy. These samples were investigated by means of an electron probe micro-analyser (EPMA) and single-crystal X-ray diffraction. Our EPMA results show that the globular aggregates have the highest REE content in the core portion and decreases to REE-bearing epidote towards the rim whereas the prismatic crystals are characterized by marked oscillatory zoning that have the highest REE contents at the rim of the crystal. The unit-cell parameters of "allanites" have an intermediate unit-cell between CaCeAl2(Fe3+ 2/3□1/3)[Si2O7][SiO4]O(OH), allanite-(Ce) and REE-free epidote, because reflect the strong chemical heterogeneity of the samples which form complete solid solutions. Hydrothermal fluids control the activity and precipitation of incompatible elements like high field strength elements (HFSE), Sc and REE by hydrous F-rich fluids below the critical temperature which allow to deposit accessory minerals in the cavities with decreasing temperature. The source of REE and Y are the sheet and REE-silicates like siderophyllite-annite, and gadolinite-(Y) which underwent partial to complete decomposition by the activity of aggressive F-rich hydrothermal fluids.

  4. Effect of thermal maturation on the K-Ar, Rb-Sr and REE systematics of an organic-rich New Albany Shale as determined by hydrous pyrolysis

    USGS Publications Warehouse

    Clauer, Norbert; Chaudhuri, Sambhudas; Lewan, M.D.; Toulkeridis, T.

    2006-01-01

    Hydrous-pyrolysis experiments were conducted on an organic-rich Devonian-Mississippian shale, which was also leached by dilute HCl before and after pyrolysis, to identify and quantify the induced chemical and isotopic changes in the rock. The experiments significantly affect the organic-mineral organization, which plays an important role in natural interactions during diagenetic hydrocarbon maturation in source rocks. They produce 10.5% of volatiles and the amount of HCl leachables almost doubles from about 6% to 11%. The Rb-Sr and K-Ar data are significantly modified, but not just by removal of radiogenic 40Ar and 87Sr, as described in many studies of natural samples at similar thermal and hydrous conditions. The determining reactions relate to alteration of the organic matter marked by a significant change in the heavy REEs in the HCl leachate after pyrolysis, underlining the potential effects of acidic fluids in natural environments. Pyrolysis induces also release from organics of some Sr with a very low 87Sr/86Sr ratio, as well as part of U. Both seem to have been volatilised during the experiment, whereas other metals such as Pb, Th and part of U appear to have been transferred from soluble phases into stable (silicate?) components. Increase of the K2O and radiogenic 40Ar contents of the silicate minerals after pyrolysis is explained by removal of other elements that could only be volatilised, as the system remains strictly closed during the experiment. The observed increase in radiogenic 40Ar implies that it was not preferentially released as a volatile gas phase when escaping the altered mineral phases. It had to be re-incorporated into newly-formed soluble phases, which is opposite to the general knowledge about the behavior of Ar in supergene natural environments. Because of the strictly closed-system conditions, hydrous-pyrolysis experiments allow to better identify and even quantify the geochemical aspects of organic-inorganic interactions, such as

  5. Metasomatic enrichment of Proterozoic mantle south of the Kaapvaal Craton, South Africa: origin of sinusoidal REE patterns in clinopyroxene and garnet

    NASA Astrophysics Data System (ADS)

    le Roex, Anton; Class, Cornelia

    2016-02-01

    Xenoliths of mantle peridotite have been sampled from four kimberlite intrusions, Melton Wold, Hebron, Uintjiesberg and Markt, emplaced through the Mesoproterozoic Namaqua-Natal Belt, along the southern border of the Kaapvaal Craton. Although many of the xenoliths are heavily altered, constituent clinopyroxene, garnet and phlogopite are fresh and have been analysed by electron microprobe for major elements and by laser ablation ICP-MS for trace elements. Primitive mantle-normalised REE abundances in clinopyroxene are all strongly LREE enriched and show a range of patterns including uniformly MREE-HREE sloped (referred to here as `normal'), sinusoidal and humped sinusoidal patterns. HREE abundances are extremely low (Yb = 0.3-0.06 × PM). REEN patterns in coexisting garnets show a similar range of patterns. When normalised to primitive mantle values, trace element patterns in some clinopyroxenes show strong relative depletion in Rb-Ba, Ta-Nb and Ti, with some samples also being relatively depleted in Zr-Hf. These trace element characteristics are indistinguishable from those found in clinopyroxene and garnet from peridotites from the adjacent cratonic mantle. Numerical modelling of reactive porous flow of an enriched metasomatic melt through a geochemically depleted peridotite matrix can account for the full range in observed REEN patterns. The relative depletion in Rb-Ba, Ta-Nb and Ti can be accounted for by an early crystallisation of phlogopite from the percolating melt. The relative depletion in Zr-Hf in some clinopyroxenes requires either zircon to crystallise in the proximal metasomatic assemblage, or metasomatism by a carbonatitic melt. Modelling results, together with the absence of clinopyroxene with depleted or even partially enriched REEN patterns, suggest that all clinopyroxene has been modally introduced through metasomatism into an initially highly depleted harzburgitic protolith. The range in Sr and Pb isotopic composition of the clinopyroxenes

  6. Biodegradation of the french reference nuclear glass SON 68 by Acidithiobacillus thiooxidans : protective effect of the biofilm,U and REE retention

    NASA Astrophysics Data System (ADS)

    Bachelet, M.; Crovisier, J.; Stille, P.; Boutin, R.; Vuilleumier, S.; Geoffroy, V.

    2008-12-01

    Although underground nuclear waste repositories are not expected to be favourable places for microbial activity, one should not exclude localized action of extremophilic bacteria on some materials involved in the storage concept. Among endogenous or accidentally introduced acidophiles, some are susceptible to lead to a locally drastic decreased in pH with potential consequences on materials corrosion. Experiments were performed with Acidithiobacillus thiooxidans on 100-125 μm french reference nuclear glass SON68 grains in a mineral medium under static conditions during 60 days at 25°C. Growth medium was periodically renewed and analyzed by ICP-AES and ICP-MS spectrometry for both major, traces and ultra-traces elements. Biofilm formation was evidenced by confocal laser microscopy, staining DNA with ethidium bromide and exopolysaccharides with calcofluor white. Biofilm thickness around material grains exceeded 20 μm under the chosen experimental conditions. It can be noticed that while numerous studies on biofilm formation upon interaction between Acidithiobacillus ferrooxidans and materials can be found in the literature, evidence for biofilm formation is still scarce for the case of the acidophilic bacterium A. thiooxidans. Presence of biofilm is a key parameter for material alteration at the solid/solution interface in biotic systems. Indeed, various constitutive elements of materials trapped in the polyanionic polymer of biofilm may also influence the alteration process. In particular, biofilm may reduce the alteration rate of materials by forming a protective barrier at their surface (Aouad et al., 2008). In this study, glass alteration rates, determined using strontium, molybdenum and caesium as tracers, showed that the biofilm has a protective effect against glass alteration. U and REE are efficiently trapped in the biogenic compartment of the system (exopolysaccharides (EPS) + bacterial cells). Biofilm analysis are in progress to determine whether these

  7. Paleoenvironments in Meso-Neoproterozoic carbonates of the Mbuji-Mayi Supergroup (Democratic Republic of Congo) - Microfacies analysis combined with C-O-Sr isotopes, major-trace elements and REE + Y distributions

    NASA Astrophysics Data System (ADS)

    Delpomdor, F.; Blanpied, C.; Virgone, A.; Préat, A.

    2013-12-01

    The Meso- and Neoproterozoic Mbuji-Mayi Supergroup (1155 Ma to ca. 800 Ma) was deposited in the SE-NW trending siliciclastic-carbonate failed-rift in the Sankuru-Mbuji-Mayi-Lomami-Lovoy Basin. Drillcore- and outcrop-derived microfacies, isotope (C, O and Sr) compositions of carbonates and REE + Y distributions are integrated to unravel the paleoenvironmental and chemical conditions prevailing during deposition and alteration (or contamination) of the Mbuji-Mayi carbonates. The carbonate succession (BIe subgroup and BIIa to BIIe subgroups), composed of 11 microfacies (MF), records the evolution of a marine ramp submitted to evaporation, with basinal and low-energy outer-ramp environments (MF1-MF5), biohermal mid-ramp (MF6) and restricted tide-dominated lagoon inner-ramp (MF7-MF9) settings, overlain by lacustrine (MF10) and sabkha (MF11) environments. The ramp margin is characterized by thick stacks of stromatolitic bioherms. δ13C and δ18O relationships in the Mbuji-Mayi carbonates allow discrimination between meteoric (δ13C: -7.5‰ to +0.0‰, δ18O: -7.0‰ to -1.0‰) and burial lithifications (δ13C: -1.5‰ to +0.0‰, δ18O: -15.1‰ to -7.0‰), that overprinted a primary marine signal (δ13C: -1.5‰ to +2.0‰, δ18O: -3.0‰ to +0.5‰) partially preserved in the subgroups. Unaltered pristine signals are found in the Mbuji-Mayi carbonates with 87Sr/86Sr ratios (0.7065-0.7082) similar to those of the marine-preserved strontium signatures of the early Neoproterozoic oceans. The PAAS-normalized REE + Y distributions indicate that the BIe carbonates were altered by Fe-oxide-rich hydrothermal fluids. BIIb and BIIe carbonates exhibit uniform light REE depleted patterns suggesting inputs of detrital river material whereas a marine seawater, highlighted by the REE + Y distributions is preserved in BIIc and BIId carbonates. The pattern of carbon, oxygen and strontium isotopic variations in the Mbuji-Mayi carbonates reflects deposition and early diagenesis in

  8. Evaluation of carbonate diagenesis: A comparative study of minor elements, trace elements, and rare-earth elements (REE + Y) between Pleistocene corals and matrices from Grand Cayman, British West Indies

    NASA Astrophysics Data System (ADS)

    Li, Rong; Jones, Brian

    2014-12-01

    On Grand Cayman, the Pleistocene Ironshore Formation consists of six unconformity-bounded units of limestones that have been partially or completely altered to calcite by post-depositional meteoric diagenesis. In order to examine the diagenetic history from the perspective of geochemical elements, the concentrations of minor element (Sr, Na, Mg), trace elements (Ba, Fe, Mn, Al, Si), and rare-earth elements (REE) and yttrium (Y) were determined for 105 corals and 84 matrices collected from the Rogers Wreck Point (RWP), Western Onshore area (WO), and offshore George Town (GT) areas. With the transformation of aragonite to calcite, the Sr, Na, and Ba values decreased, but Mg increased, which are indicative of diagenetic alteration in an open water system. Due to intrinsic "vital effects" and the extrinsic diagenetic environment, the variations of Sr, Na, Ba, and Mg concentrations between Acropora and Montastrea from the GT area are different to those of their counterparts from RWP and WO. The signatures of Sr, Na, Ba, and Mg are in good agreement with the diagenetic history as determined from petrographic and stable isotopic criteria. The REE + Y (REY) concentrations (ΣREY) are higher in the matrices (0.2-6.9 ppm, average 2.6 ppm) than in the associated corals (0.1-5.4 ppm, average 0.6 ppm). Shale-normalized REY patterns of the Pleistocene Ironshore Formation are similar to those of oxygenated seawater, which are characterized by (1) light REE depletion relative to heavy REE (average DySN/SmSN = 1.7, n = 35), (2) positive La anomalies (average Pr/Pr* = 1.17, n = 53), and (3) negative Ce anomalies (average Ce/Ce* = 0.49, n = 53). The preserved seawater-like REY distribution pattern, the lack of correlation between ΣREY and mineralogy, and the lack of correlation between ΣREY and diagenesis-sensitive stable oxygen isotope (δ18O) indicate that meteoric diagenesis did not have a major impact on the REY distribution patterns. The matrices and corals in the GT area

  9. Petrographic, REE, fluid inclusion and stable isotope study of magnesite from the Upper Triassic Burano Evaporites (Secchia Valley, northern Apennines): contributions from sedimentary, hydrothermal and metasomatic sources

    NASA Astrophysics Data System (ADS)

    Lugli, Stefano; Morteani, Giulio; Blamart, Dominique

    2002-06-01

    Sparry and microcrystalline magnesite are minor constituents of the Upper Triassic Burano Evaporite Formation of the northern Apennines in Italy. Petrography and geochemistry of magnesite suggest three modes of formation. (1) Evaporitic precipitation of stratified microcrystalline magnesite layers associated with sulfate and carbonate rocks. Most REE are below ICP-MS detection limits. δ18O is +20.2‰ (SMOW) and δ13C is -2.6‰ (PDB). (2) Hydrothermal infill of Fe-rich (9.78 wt% FeO) lenticular sparry magnesite. This type of magnesite is characterized by very low LREE concentrations, whereas HREEs are relatively high. The fluid inclusion composition is NaCl-MgCl2-H2O, salinity is ~30 wt% NaCl equiv., and total homogenization temperatures range from 204-309 °C; δ18O is +17.5‰ and δ13C is +1‰. (3) The partial or total replacement of dolostones by lenticular sparry magnesite. LREEs are lower in magnesite compared with the partly replaced dolostones. Magnesite yields δ18O and δ13C compositions of +17.3 to +23.6‰ and +0.5 to +1.4‰, respectively, whereas the partly replaced dolostones yield δ18O and δ13C values of +25.0 to +26.2 and +1.3 to +1.9, respectively. Complete replacement of dolostones produced massive lenticular sparry magnesite rock containing ooids and axe-head anhydrite relicts; LREEs are depleted compared to unaffected dolostones; δ18O and δ13C compositions range from +16.4 to +18.4‰ and +0.4 to +0.9‰, respectively. These data and the association between fracture-filling and replacive magnesite suggests a metasomatic system induced by hydrothermal circulation of hot and saline Mg-rich fluids. These processes probably occurred in the Oligocene-Miocene, when the Burano Formation acted as main detachment horizon for the Tuscan Nappe during the greenschist facies metamorphism of the Apuane complex. Thrusting over the Apuane zone produced large scale fluid flow focused at the Tuscan Nappe front. Sources of Mg-rich fluids were metamorphic

  10. Stable H-C-O isotope and trace element geochemistry of the Cummins Range Carbonatite Complex, Kimberley region, Western Australia: implications for hydrothermal REE mineralization, carbonatite evolution and mantle source regions

    NASA Astrophysics Data System (ADS)

    Downes, Peter J.; Demény, Attila; Czuppon, György; Jaques, A. Lynton; Verrall, Michael; Sweetapple, Marcus; Adams, David; McNaughton, Neal J.; Gwalani, Lalchand G.; Griffin, Brendan J.

    2014-12-01

    The Neoproterozoic Cummins Range Carbonatite Complex (CRCC) is situated in the southern Halls Creek Orogen adjacent to the Kimberley Craton in northern Western Australia. The CRCC is a composite, subvertical to vertical stock ˜2 km across with a rim of phlogopite-diopside clinopyroxenite surrounding a plug of calcite carbonatite and dolomite carbonatite dykes and veins that contain variable proportions of apatite-phlogopite-magnetite ± pyrochlore ± metasomatic Na-Ca amphiboles ± zircon. Early high-Sr calcite carbonatites (4,800-6,060 ppm Sr; La/YbCN = 31.6-41.5; δ13C = -4.2 to -4.0 ‰) possibly were derived from a carbonated silicate parental magma by fractional crystallization. Associated high-Sr dolomite carbonatites (4,090-6,310 ppm Sr; La/YbCN = 96.5-352) and a late-stage, narrow, high rare earth element (REE) dolomite carbonatite dyke (La/YbCN = 2756) define a shift in the C-O stable isotope data (δ18O = 7.5 to 12.6 ‰; δ13C = -4.2 to -2.2 ‰) from the primary carbonatite field that may have been produced by Rayleigh fractionation with magma crystallization and cooling or through crustal contamination via fluid infiltration. Past exploration has focussed primarily on the secondary monazite-(Ce)-rich REE and U mineralization in the oxidized zone overlying the carbonatite. However, high-grade primary hydrothermal REE mineralization also occurs in narrow (<1 m wide) shear-zone hosted lenses of apatite-monazite-(Ce) and foliated monazite-(Ce)-talc rocks (≤˜25.8 wt% total rare earth oxide (TREO); La/YbCN = 30,085), as well as in high-REE dolomite carbonatite dykes (3.43 wt% TREO), where calcite, parisite-(Ce) and synchysite-(Ce) replace monazite-(Ce) after apatite. Primary magmatic carbonatites were widely hydrothermally dolomitized to produce low-Sr dolomite carbonatite (38.5-282 ppm Sr; La/YbCN = 38.4-158.4; δ18O = 20.8 to 21.9 ‰; δ13C = -4.3 to -3.6 ‰) that contains weak REE mineralization in replacement textures, veins and coating vugs. The

  11. Contrasting geochemical and Sm-Nd isotopic compositions of Archean metasediments from the Kongling high-grade terrain of the Yangtze craton: Evidence for cratonic evolution and redistribution of REE during crustal anatexis

    NASA Astrophysics Data System (ADS)

    Gao, Shan; Ling, Wenli; Qiu, Yumin; Lian, Zhou; Hartmann, Gerald; Simon, Klaus

    1999-07-01

    Twenty-three clastic metasediments from the Kongling high-grade terrain of the Yangtze craton, South China were analyzed for major, trace and rare earth elements and Sm-Nd isotopic ratios. Associated dioritic-tonalitic-trondhjemitic (DTT) and granitic gneisses as well as amphibolites were also analyzed in order to constrain provenance. The results show that the clastic metasediments can be classified into 3 distinct groups in terms of mineralogical, geochemical and Sm-Nd isotopic compositions. Group A is characterized by having no to slight negative Eu anomalies (Eu/Eu∗ = 0.82-1.07), being high in Cr (191-396 ppm) and Ni (68-137 ppm), and low in Th (3.3-7.8 ppm) and REEREE = 99-156 ppm). These characteristics are similar to those of metasediments from Archean greenstone belts. In addition, the Group A metasediments have the value of the Chemical Index of Alteration (CIW) close to felsic gneisses. Their Sm-Nd isotopic, REE and trace element compositions can be interpreted by mixtures of the DTT gneisses and amphibolites. Dating of detrital zircons from 2 Group A samples by SHRIMP reveals a major concordant age group of 2.87-3.0 Ga, which is identical to the age of the trondhjemitic gneiss. These results strongly suggest that Group A was principally the first-cycle erosion product of the local Kongling DTT gneiss and amphibolite. Moreover, the higher than amphibolite Cr content and slight Eu depletion exhibited by some samples from this group infer that ultramafic rocks like komatiite and granite of probably 3.0-3.3 Ga in age also played a role. Group B is characterized by the presence of graphite and shows a more evolved composition similar to post-Archean shales with a prominent negative Eu anomaly (Eu/Eu∗ = 0.48-0.77) and high CIW. On paired Cr/Th vs La/Co and Co/Th plots, Group B samples conform to a two-end member mixing line of the Kongling granitic gneiss and amphibolite. However, data on Nd model age and CIW suggest that the granite component should

  12. Comparison of experimental data on detonation velocity and Chapman-Jouget pressure vs initial HE density with predictions from Ree's model equation of state. [RDX and HMX which are homologous nitramines of the family (CH/sub 2/N/sub 2/O/sub 2/)/sub n/ where n is 3 for RDX and 4 for HMX

    SciTech Connect

    Steinberg, D J

    1985-02-01

    Data on the change of detonation velocity and Chapman-Jouget pressure vs initial HE density for RDX and HMX have been compared with the theoretical predictions of Ree for PBX 9404. Ree's model predicts breaks or changes in the slope of these curves due to the solidification of carbon and the formation of a separate, nitrogen-rich phase. There is good evidence for the solidification of carbon at rho/sub 0/ about 1.15 g/cc, but the evidence for the nitrogen phase separation at rho/sub 0/ about 1.56 g/cc is conflicting. 14 refs., 6 figs., 1 tab.

  13. Origin of the eclogitic clasts with graphite-bearing and graphite-free lithologies in the Northwest Africa 801 (CR2) chondrite: Possible origin from a Moon-sized planetary body inferred from chemistry, oxygen isotopes and REE abundances

    NASA Astrophysics Data System (ADS)

    Hiyagon, H.; Sugiura, N.; Kita, N. T.; Kimura, M.; Morishita, Y.; Takehana, Y.

    2016-08-01

    In order to clarify the origin of the eclogitic clasts found in the NWA801 (CR2) chondrite (Kimura et al., 2013), especially, that of the high pressure and temperature (P-T) condition (∼3 GPa and ∼1000 °C), we conducted ion microprobe analyses of oxygen isotopes and rare earth element (REE) abundances in the clasts. Oxygen isotopic compositions of the graphite-bearing lithology (GBL) and graphite-free lithology (GFL) show a slope ∼0.6 correlation slightly below the CR-CH-CB chondrites field in the O three-isotope-diagram, with a large variation for the former and almost homogeneous composition for the latter. The average REE abundances of the two lithologies show almost unfractionated patterns. Based on these newly obtained data, as well as mineralogical observations, bulk chemistry, and considerations about diffusion timescales for various elements, we discuss in detail the formation history of the clasts. Consistency of the geothermobarometers used by Kimura et al. (2013), suggesting equilibration of various elements among different mineral pairs, provides a strong constraint for the duration of the high P-T condition. We suggest that the high P-T condition lasted 102-103 years. This clearly precludes a shock high pressure (HP) model, and hence, strongly supports a static HP model. A static HP model requires a Moon-sized planetary body of ∼1500 km in radius. Furthermore, it implies two successive violent collisions, first at the formation of the large planetary body, when the clasts were placed its deep interior, and second, at the disruption of the large planetary body, when the clasts were expelled out of the parent body and later on transported to the accretion region of the CR chondrites. We also discuss possible origin of O isotopic variations in GBL, and presence/absence of graphite in GBL/GFL, respectively, in relation to smelting possibly occurred during the igneous process(es) which formed the two lithologies. Finally we present a possible

  14. Fluid sources and metallogenesis in the Blackbird Co-Cu-Au-Bi-Y-REE district, Idaho, U.S.A.: Insights from major-element and boron isotopic compositions of tourmaline

    USGS Publications Warehouse

    Trumbull, R.B.; Slack, J.F.; Krienitz, M.-S.; Belkin, H.E.; Wiedenbeck, M.

    2011-01-01

    Tourmaline is a widespread mineral in the Mesoproterozoic Blackbird Co-Cu-Au-Bi-Y-REE district, Idaho, where it occurs in both mineralized zones and wallrocks. We report here major-element and B-isotope compositions of tourmaline from stratabound sulfide deposits and their metasedimentary wallrocks, from mineralized and barren pipes of tourmaline breccia, from late barren quartz veins, and from Mesoproterozoic granite. The tourmalines are aluminous, intermediate in the schorl-dravite series, with Fe/(Fe + Mg) values of 0.30 to 0.85, and 10 to 50% X-site vacancies. Compositional zoning is prominent only in tourmaline from breccias and quartz veins; crystal rims are enriched in Mg, Ca and Ti, and depleted in Fe and Al relative to cores. The chemical composition of tourmaline does not correlate with the presence or absence of mineralization. The ??11B values fall into two groups. Isotopically light tourmaline (-21.7 to-7.6%o) occurs in unmineralized samples from wallrocks, late quartz veins and Mesoproterozoic granite, whereas heavy tourmaline (-6.9 to +3.2%o) is spatially associated with mineralization (stratabound and breccia-hosted), and is also found in barren breccia. At an inferred temperature of 300??C, boron in the hydrothermal fluid associated with mineralization had ??11B values of-3 to +7%o. The high end of this range indicates a marine source of the boron. A likely scenario involves leaching of boron principally from marine carbonate beds or B-bearing evaporites in Mesoproterozoic strata of the region. The ??11B values of the isotopically light tourmaline in the sulfide deposits are attributed to recrystallization during Cretaceous metamorphism, superimposed on a light boron component derived from footwall siliciclastic sediments (e.g., marine clays) during Mesoproterozoic mineralization, and possibly a minor component of light boron from a magmatic-hydrothermal fluid. The metal association of Bi-Be-Y-REE in the Blackbird ores suggests some magmatic input

  15. REE and Y in groundwater in the upper 1.2 km of Proterozoic granitoids (Eastern Sweden) - Assessing the role of composition and origin of groundwaters, geochemistry of fractures, and organic/inorganic aqueous complexation

    NASA Astrophysics Data System (ADS)

    Mathurin, Frédéric A.; Åström, Mats E.; Drake, Henrik; Maskenskaya, Olga M.; Kalinowski, Birgitta E.

    2014-11-01

    Yttrium and rare earth elements (YREEs) are studied in groundwater in the shallow regolith aquifer and the fracture networks of the upper 1.2 km of Paleoproterozoic granitoids in boreal Europe (Laxemar and Forsmark areas, Sweden). The study includes groundwater sampled via a total of 34 shallow boreholes reaching the bottom of the regolith aquifer, and 72 deep boreholes with equipment designed for retrieval of representative groundwater at controlled depths in the fractured bedrock. The groundwater composition differs substantially between regolith and fracture groundwater and between areas, which affects the dissolved YREE features, including concentrations and NASC normalized patterns. In the fresh groundwater in the regolith aquifers, highest YREE concentrations occur (10th and 90th percentile; Laxemar: 4.4-82 μg L-1; Forsmark: 1.9-19 μg L-1), especially in the slightly acidic groundwater (pH: 6.3-7.2 - Laxemar), where the normalized YREE patterns are slightly enriched in light REEs (LaNASC/YNASC: 1.1-2.4). In the recharge areas, where redox potentials of the regolith groundwater is more moderate, negative Ce anomaly (Laxemar: 0.37-0.45; Forsmark: 0.15-0.92) and positive Y anomaly (mainly in Forsmark: 1.0-1.7) are systematically more pronounced than in discharge areas. The significant correlations between the YREE features and dissolved organic carbon, minor elements, and somewhat pH suggest a strong control of humic substances (HSs) together with Al rich colloids and redox sensitive Fe-Mn hydrous precipitates on the dissolved YREE pools. In the bedrock fractures, the groundwater is circumneutral to slightly basic and displays YREE concentrations that are at least one order of magnitude lower than the regolith groundwater, and commonly below detection limit in the deep brackish and saline groundwater, with some exceptions such as La and Y. At intermediate depth (>50 m), where groundwater of meteoric origin percolates, the LaNASC/YNASC values moderately to

  16. Zircon U-Pb ages and Sr-Nd-Hf isotopes of the highly fractionated granite with tetrad REE patterns in the Shamai tungsten deposit in eastern Inner Mongolia, China: Implications for the timing of mineralization and ore genesis

    NASA Astrophysics Data System (ADS)

    Jiang, Si-Hong; Bagas, Leon; Hu, Peng; Han, Ning; Chen, Chun-Liang; Liu, Yuan; Kang, Huan

    2016-09-01

    The Shamai tungsten deposit is located in the eastern part of the Central Asian Orogenic Belt (CAOB). Tungsten mineralization is closely related to the emplacement of fine- to medium-grained biotite monzogranite (G1) and porphyritic biotite monzogranite (G2) in the Shamai Granite. NW-trending joints and faults host orebodies in the Shamai Granite and Devonian hornfels. The mineralization is characterized by a basal veinlet zone progressing upwards to a thick vein zone followed by a mixed zone, a veinlet zone, and a thread vein zone at the top. The ore-related alteration typically consists of muscovite, greisen, and hornfels. In order to constrain the timing of the Shamai mineralization and discuss the ore genesis, muscovite Ar-Ar, molybdenite Re-Os, and zircon U-Pb geochronological, geochemical, and Sr-Nd-Hf isotopic studies were completed on the deposit. The U-Pb zircon dating yielded weighted mean ages of 153 ± 1 Ma for G1 and 146 ± 1 Ma for G2. Muscovite from a wolframite-bearing quartz vein yielded an Ar-Ar plateau age of 140 ± 1 Ma, whereas two molybdenite samples yielded identical Re-Os model ages of 137 ± 2 Ma. These two ages are younger than the two monzogranites, suggesting a prolonged magmatic-hydrothermal interaction during tungsten mineralization. Major and trace element geochemistry shows that both G1 and G2 are characterized by high SiO2 and K2O contents, high A/CNK values (1.08-1.40), a spectacular tetrad effect in their REE distribution patterns, and non-CHARAC (charge-and-radius-controlled) trace element behavior. This suggests that both G1 and G2 are highly differentiated peraluminous rocks with strong hydrothermal interaction. The Nd-Hf isotope data for the Shamai Granite (εNd(t) between - 1.9 and + 7.4, ɛHf(t) from 5.2 to 12.8) are largely compatible with the general scenario for much of the Phanerozoic granite emplaced in the CAOB. It is here suggested that the Shamai Granite originated from partial melting of a juvenile lower crust with

  17. Implications of Competition for Rare Earth Elements (REE) in Africa

    DTIC Science & Technology

    2011-03-15

    Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202- 4302. Respondents should be aware that...2010). 3 Marc Humphries , ―Rare Earth Elements: The Global Supply Chain,‖ Congressional Research Service Report for Congress R41347 (September 30...101026_Verrastro_Geopolitics_web.pdf (accessed October 14, 2010). 10 Humphries , ―Rare Earth Elements: The Global Supply Chain,‖ (September 30, 2010): 4

  18. Th-REE- and Nb-Ta-accessory minerals in post-collisional Ediacaran felsic rocks from the Katerina Ring Complex (S. Sinai, Egypt): An assessment for the fractionation of Y/Nb, Th/Nb, La/Nb and Ce/Pb in highly evolved A-type granites

    NASA Astrophysics Data System (ADS)

    Moreno, J. A.; Molina, J. F.; Bea, F.; Abu Anbar, M.; Montero, P.

    2016-08-01

    The relationships of Y/Nb, Th/Nb, La/Nb and Ce/Pb ratios in A-type felsic rocks from the Ediacaran Katerina Ring Complex, northernmost Arabian-Nubian Shield (ANS; S. Sinai, Egypt), are investigated in this work to understand their behavior during generation of highly evolved granitic magmas and to explore the nature of magma sources. Textural and compositional relationships of cognate Th-REE- and Nb-Ta-accessory minerals in Katerina felsic rocks show that chevkinite-group minerals (CGM), monazite, thorite, allanite and xenotime formed from residual liquids in quartz syenite porphyries, quartz monzonites and peralkaline granites, whereas in aluminous granites, allanite and monazite crystallized early, and thorite and columbite formed from residual liquids. Relationships of Y/Nb, Th/Nb, La/Nb and Ce/Pb ratios with Zr/Hf ratios in the aluminous granites and with Be abundances in the peralkaline granites suggest a decrease in La/Nb and Ce/Pb ratios in the former, and in Y/Nb and La/Nb ratios in the latter with crystallization progress. This contrasts with absence of systematic variations of Th/Nb and Ce/Pb ratios in the peralkaline compositions and of Y/Nb ratio in the aluminous ones. In this latter, Th/Nb ratio can present a significant decrease only in highly evolved compositions. An analysis of Y/Nb, Th/Nb, La/Nb and Ce/Pb relationships in worldwide OIB and subduction-related magmatic suites reveals that A-type felsic rocks with (Th/Nb)N < 1.3, (La/Nb)N < 1.3, and (Ce/Pb)N > 1 may have A1-type affinity, and those with (Th/Nb)N > 2, (La/Nb)N > 2, and (Ce/Pb)N < 1 tend to present A2-type affinity. The crystal fractionation of Th-LREE- and Nb-Ta-accessory minerals and mixing of components derived from the two granite groups may cause deviations from these compositional limits that can be evaluated using constraints imposed by Th/Nb-La/Nb, Ce/Pb-Th/Nb and Ce/Pb-La/Nb relationships in OIB and subduction-related magmatic suites. Three mantle sources might have been

  19. Golan Heights Groundwater Systems: Separation By REE+Y And Stable Isotopes

    NASA Astrophysics Data System (ADS)

    Siebert, C.; Geyer, S.; Knoeller, K.; Roediger, T.; Weise, S.; Dulski, P.; Moeller, P.; Guttman, J.

    2008-12-01

    In a semi-arid to arid country like Israel, all freshwater resources are under (over-) utilization. Particularly, the Golan Heights rank as one of the most important extraction areas of groundwater of good quality and quantity. Additionally the mountain range feed to a high degree the most important freshwater reservoir of Israel, the Sea of Galilee. Hence, knowing the sources and characters of the Golan Heights groundwater systems is an instantaneous demand regarding sustainable management and protection. Within the "German-Israeli-Jordanian-Palestinian Joint Research Program for the Sustainable Utilisation of Aquifer Systems", hundreds of water samples were taken from all over the Jordan-Dead Sea rift-system to understand groundwater flow-systems and salinisation. For that purpose, each sample was analysed for major and minor ions, rare earth elements including yttrium (REY) and stable isotopes of water (d18O, d2H). The REY distribution in groundwater is established during infiltration by the first water-rock interaction and consequently reflects the leachable components of sediments and rocks of the recharge area. In well- developed flow-systems, REY are adsorbed onto pore surfaces are in equilibrium with the percolating groundwater, even if the lithology changes (e.g. inter-aquifer flow). Thus, groundwater sampled from wells and springs still show the REY distribution pattern established in the recharge area. Since high temperatures do not occur in Golan Heights, d2H and d18O are less controlled by water-rock interaction than by climatic and geomorphological factors at the time of replenishment. Applying the REY signature as a grouping criterion of groundwaters, d18O vs. d2H plots yield a new dimension in interpreting isotope data. The combined use of hydrochemical and isotopic methods enabled us to contain the areas of replenishment and the flow-paths of all investigated groundwater in the Golan Heights. Despite location, salinity or temperature of spring or well waters, stable isotopes showed, that the main area of recharge is the elevated Hermon-Massif, with high annually precipitation amounts. The major element composition of fresh water well Alonei HaBashan 3, situated in the basaltic Upper Golan Heights, is defined by a pre-Neogenic limy aquifer and the contact to basalts. However, REY pattern refer to a calcareous infiltration area. Stable isotope signatures are lighter than in the recharge of comparable elevated Upper Galilee. Further to the south, in the Yarmouk gorge hot Mezar springs occur, which show stable isotope signatures even lighter than in water of Alonei Habshan 3. Both, REY pattern and hydrochemistry show infiltration into and contact to the Sr-rich limestone aquifer of the Mt. Scopus group. That adds up to an infiltration area some 50 km to the north, the nearest elevated area where carbonates crop out. Nearby Mezar, hot Hammat Gader springs occur, which show comparable isotopic signatures and hydrochemical composition. However, the REY-patterns indicate infiltration in basalts. By means of those three examples we could show, that the use of a combined hydrochemical and isotopic approach reveals complex and large-scale groundwater infiltration- and flow-systems much better than a focused view on a specific band of elements.

  20. The Nakhla parent melt: REE partition coefficients and clues to major element composition

    NASA Technical Reports Server (NTRS)

    Mckay, G.; Le, L.; Wagstaff, J.

    1993-01-01

    Nakhla is one of the SNC meteorites, generally believed to be of Martian origin. It is a medium-grained augite-olivine cumulate with a variolitic groundmass of sodic plagioclase, alkali feldspar, and Fe-rich pyroxenes and olivine. One of the major tasks in deciphering Nakhla's petrogenesis is determining the composition of its parent melt. Gaining an understanding of the composition and petrogenesis of this parent melt may help unravel Nakhla's relationship to the other SNCs, and provide clues to Martian petrogenesis in general. Our experimental partitioning studies provide new information that helps constrain both the major and trace element composition of the Nakhla parent melt.

  1. REE Partition Coefficients from Synthetic Diogenite-Like Enstatite and the Implications of Petrogenetic Modeling

    NASA Technical Reports Server (NTRS)

    Schwandt, C. S.; McKay, G. A.

    1996-01-01

    Determining the petrogenesis of eucrites (basaltic achondrites) and diogenites (orthopyroxenites) and the possible links between the meteorite types was initiated 30 years ago by Mason. Since then, most investigators have worked on this question. A few contrasting theories have emerged, with the important distinction being whether or not there is a direct genetic link between eucrites and diogenites. One theory suggests that diogenites are cumulates resulting from the fractional crystallization of a parent magma with the eucrites crystallizing, from the residual magma after separation from the diogenite cumulates. Another model proposes that diogenites are cumulates formed from partial melts derived from a source region depleted by the prior generation of eucrite melts. It has also been proposed that the diogenites may not be directly linked to the eucrites and that they are cumulates derived from melts that are more orthopyroxene normative than the eucrites. This last theory has recently received more analytical and experimental support. One of the difficulties with petrogenetic modeling is that it requires appropriate partition coefficients for modeling because they are dependent on temperature, pressure, and composition. For this reason, we set out to determine minor- and trace-element partition coefficients for diogenite-like orthopyroxene. We have accomplished this task and now have enstatite/melt partition coefficients for Al, Cr, Ti, La, Ce, Nd, Sm, Eu, Dy, Er, Yb, and La.

  2. Electron Probe Microanalysis of REE in Eudialyte Group Minerals: Challenges and Solutions.

    PubMed

    Atanasova, Petya; Krause, Joachim; Möckel, Robert; Osbahr, Inga; Gutzmer, Jens

    2015-10-01

    Accurate quantification of the chemical composition of eudialyte group minerals (EGM) with the electron probe microanalyzer is complicated by both mineralogical and X-ray-specific challenges. These include structural and chemical variability, mutual interferences of X-ray lines, in particular of the rare earth elements, diffusive volatility of light anions and cations, and instability of EGM under the electron beam. A novel analytical approach has been developed to overcome these analytical challenges. The effect of diffusive volatility and beam damage is shown to be minimal when a square of 20×20 µm is scanned with a beam diameter of 6 µm at the fastest possible speed, while measuring elements critical to electron beam exposure early in the measurement sequence. Appropriate reference materials are selected for calibration considering their volatile content and composition, and supplementary offline overlap correction is performed using individual calibration factors. Preliminary results indicate good agreement with data from laser ablation inductively coupled plasma mass spectrometry demonstrating that a quantitative mineral chemical analysis of EGM by electron probe microanalysis is possible once all the parameters mentioned above are accounted for.

  3. Fluid inclusion and stable isotope data for the Pea Ridge Fe-REE orebody, Missouri

    SciTech Connect

    Sidder, G.B.; Day, W.C.; Rye, R.O. )

    1993-03-01

    New fluid-inclusion and stable-isotope data define the character of the mineralizing fluids that formed the iron and rare-earth-element ore deposit at the Pea Ridge Mine, southeast Missouri. These fluids were very hot and highly saline brines that may have been magmatically derived. Early, pre-magnetite ore skarn alteration of the host rhyolitic tuff took place at temperatures greater than 420 C and possibly as high as 680 C based upon calculated temperatures of quartz-magnetite pairs. Halite homogenization of three- or more phase (liquid + vapor + salts) fluid inclusions in quartz indicates that the skarn-forming fluid had a temperature of about 460 C to > 530 C and a salinity of about 45 to 57 equivalent weight percent NaCl. Analyses of [delta][sup 18]O in quartz from the skarn zone average about 14.5[per thousand], compared to a value of about 13.0[per thousand] for quartz in the host rhyolite. Average [delta][sup 34]S values for pyrite of about 2.3[per thousand] in the skarn zone may reflect a magmatic source. Magnetite ore was deposited at temperatures between about 340 C and 530 C from a fluid with a salinity between about 54 and 60 equivalent weight percent NaCl. The large apparent range of temperatures indicated by both fluid-inclusion and stable-isotope data within each zone may be due to contamination by quartz from multiple stages of quartz deposition. Also, the assumed isotopic equilibrium between some mineral pairs may be incorrect. Moreover, fluid inclusions are relatively rare in all ore and alteration zones except the silicified zone, and only a few inclusions are clearly primary in origin. Nonetheless, the predominance of high temperatures and high salinities in all of the mineralized and altered zones supports the interpretation that Pea ridge is a magmatic hydrothermal deposit. This magmatic hydrothermal model is also supported by paragenetic relations defined by geologic mapping and geochemical modeling of major-, minor-, and trace-element data.

  4. Chemical characteristics (REE, etc.) of Paleozoic and Mesozoic graywackes and sandstones from Central Europe

    NASA Astrophysics Data System (ADS)

    Wedepohl, Karl Hans; Simon, Klaus

    2012-10-01

    During the Variscan orogeny in Central Europe, partial melting in the lower continental crust formed granitic magmas, which intruded into the upper crust and left compounds of Ca (plus Eu2+), Mg, etc. in the lower crust. From the late Paleozoic decomposition of the tonalitic upper crust, sedimentary graywackes were produced reflecting the composition of this crust. The repeated reworking of the sedimentary cover caused the formation of sands. Sandstones as their products of consolidation contain increasing fractions of quartz and decreasing feldspar from Carboniferous and Triassic to Cretaceous age. A distinct negative Eu anomaly characterizes the majority of these rocks. The latter is imprinted by the Variscan magmatism. Quartz as used for numerous Medieval wood ash glasses is marked for its Central European origin by a distinct negative Eu anomaly in contrast to many soda glasses produced outside Germany mostly with a small or none Eu anomaly.

  5. VizieR Online Data Catalog: Radio galaxies in ZFOURGE/NMBS (Rees+, 2016)

    NASA Astrophysics Data System (ADS)

    Rees, G. A.; Spitler, L. R.; Norris, R. P.; Cowley, M. J.; Papovich, C.; Glazebrook, K.; Quadri, R. F.; Straatman, C. M. S.; Allen, R.; Kacprzak, G. G.; Labbe, I.; Nanayakkara, T.; Tomczak, A. R.; Tran, K.-V.

    2016-07-01

    Our primary data are the pre-release Ks-selected galaxy catalogues from the FourStar Galaxy Evolution (ZFOURGE) survey (Straatman et al., submitted; Spitler et al., 2012ApJ...748L..21S; Tilvi et al., 2013ApJ...768...56T; Straatman et al., 2013ApJ...768...56T). This survey covers the CDF-S (Chandra Deep Field-South) and COSMOS (Cosmic Evolution Survey) fields (Giacconi et al., 2001ApJ...551..624G; Schinnerer et al., 2004, Cat. J/AJ/128/1974). Each 11-arcminx11-arcmin field is imaged at a resolution of 0.6-arcsec down to an 80 per cent Ks band, point source magnitude limit of 24.53 and 24.74ABmag for the CDF-S and COSMOS fields, respectively. Radio detections in the CDF-S field are determined from the images and catalogues of the Very Large Array (VLA) 1.4GHz Survey of the Extended Chandra Deep Field-South: Second Data Release (Miller et al., 2013, Cat. J/ApJS/205/13). (5 data files).

  6. Using Rare Earth Elements (REE) to determine wind-driven soil dispersal from a point source

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although erosion of soil by water is a predictably directional process, the erosion of soil by wind is determined by wind direction on an event-wise basis. The wind-driven dispersal patterns of chemical constituents including natural soil components and anthropogenic contaminants are not well under...

  7. Effect of Titanium on REE and HFSE Partitioning Between Garnet and Melt

    NASA Astrophysics Data System (ADS)

    Dwarzski, R. E.; Draper, D. S.

    2004-12-01

    Garnet is a strong fractionator of trace elements and plays an important role in the petrogenetic history of planetary interiors at high pressure. In order to model petrogenetic processes that operate within terrestrial planets accurately, it is important to understand how garnet partitions rare earth and high field strength elements. Here we assess the influence of Ti on garnet-melt trace element partitioning with a view both to constrain important crystal-chemical effects and to evaluate possible roles for garnet in lunar petrogenesis. Experiments were performed at ˜5 GPa and 1650-1675° C in a Walker-style multi-anvil high pressure apparatus using an Apollo 14 black picritic glass composition ( ˜17 wt% TiO2) to assess the effect of Ti on garnet partitioning. These experiments were also designed to examine the possible presence of garnet in mare source regions. Experimental charges were analyzed for major and trace elements by EPMA and SIMS, respectively. D-values measured in this study using the Apollo 14 black Ti-rich composition are consistently higher than those measured by Draper et al. (2004, LPSC XXXV:1297), who used Apollo 15 green C glass (<0.5 wt% TiO2). D vs. ionic radii are well-described for the trivalent cations by the lattice-strain partitioning model of Blundy and Wood (1994, Nature 372:452), with D0 = 2.27 ± 0.40, E = 159 ± 58 GPa, and r0 = 0.879 ± 0.044 Å (r2 = 0.957). For comparison, this model applied to the low-Ti experiments of Draper et al. (2004) yields D0 = 2.93 ± 0.25, E = 572 ± 40 GPa, and r0 = 0.926 ± 0.005 Å (r2 = 0.996) at ˜3.5 GPa. Both these fits show significant mismatch to the partitioning predicted by the formulations of van Westrenen et al. (2001, CMP 142:219), as previously shown for Fe-rich systems by Draper et al. (2003, PEPI 139:149). Use of our D-values (for rare earth and high field strength elements in batch-melting models) provisionally supports the hypotheses of Neal (2001, JGR 106:27865) and Neal and Shearer (2004, LPSC XXXV:2135), who proposed that garnet was present in the source regions of lunar mare basalts. The results of these calculations are similar to those using data from garnet-melt partitioning in very Ti-poor systems (Draper et al. 2004).

  8. Tambo Quemado: Extraordinary concentrations of REE and refractory trace elements caused by artificial heating

    NASA Technical Reports Server (NTRS)

    Olsen, E.; Hutcheon, I.; Moore, C.

    1993-01-01

    Buchwald examined samples of the IIIB iron Tambo Quemado (TAMQ) cut from the 130 kg main mass. He determined it had been artificially heated, at some time prior to being reported, in an attempt to obtain metal from it. Although the Widmanstatten structure appears relatively unaffected under macroscopic examination, microscopic study of etched sections reveals the effect of the heating. Taenite and plessite area boundaries are indistinct due to high temperature diffusion. Schreibersite, once present in significant amounts, has been melted. Schreibersites in the interior have resolidified in fine-grained eutectic textures surrounded by dark-etching metal rims supersaturated with phosphorus. Buchwald states that phosphate minerals were probably present originally, because graftonite, and its polymorph sarcopside (both essentially Fe3(PO4)2), are common in irons of the IIIB groups. Based on his metallographic study Buchwald estimates TAMQ was heated to 1000 C for about one hour. An interior sample from TAMQ was examined in order to determine what effect this unintended heating 'experiment' had upon the phosphate phases.

  9. The distribution of Sr and REE between diopside and silicate liquid. [Rare Earth Elements

    NASA Technical Reports Server (NTRS)

    Grutzeck, M.; Kridelbaugh, S.; Weill, D.

    1974-01-01

    Experimental determination of the distribution coefficients in diopside-liquid pairs for strontium and nine rare-earth elements in the system CaMgSi2O6-NaAlSi3O8-CaAl2Si2O8. In experiments in air at 1265 C it is found that most of the Sr(2+), Eu(2+), and RE(3+) ions substitute for Ca(2+) and, in addition, a coupled substitution of Al(3+) for Si(4+) occurs. All of the trace ions considered are found to be excluded from the diopside lattice relative to the liquid. In the case of the trivalent ions the exclusion is much more pronounced for La and Ce, which have ionic radii larger than that of Ca(2+) in 8-fold oxygen coordination. Divalent Sr and Eu with even larger radii are also strongly excluded.

  10. Correlations Between Surficial Sulfur and a REE Crustal Assimilation Signature in Martian Shergottites

    NASA Technical Reports Server (NTRS)

    Jones, J. H.; Franz, H. B.

    2015-01-01

    Compared to terrestrial basalts, the Martian shergottite meteorites have an extraordinary range of Sr and Nd isotopic signatures. In addition, the S isotopic compositions of many shergottites show evidence of interaction with the Martian surface/ atmosphere through mass-independent isotopic fractionations (MIF, positive, non-zero delta(exp 33)S) that must have originated in the Martian atmosphere, yet ultimately were incorporated into igneous sulfides (AVS - acid-volatile sulfur). These positive delta(exp 33)S signatures are thought to be governed by solar UV photochemical processes. And to the extent that S is bound to Mars and not lost to space from the upper atmosphere, a positive delta(exp 33)S reservoir must be mass balanced by a complementary negative reservoir.

  11. SM-ND Age and REE Systematics of Larkman Nunatek 06319: Closed System Fractional Crystallization of a Shergottite Magma

    NASA Technical Reports Server (NTRS)

    Shafer, J. T.; Brandon, A. D.; Lapen T. J.; Righter, M.; Peslier, A. H.

    2010-01-01

    Sm-Nd isotopic data were collected on mineral separates and bulk rock powders of LAR 06319, yielding an age of 180+/-13 Ma (2(sigma)). This age is concordant with the Lu-Hf age (197+/-29 Ma, [1]) determined in conjunction with these data and the Sm-Nd age (190+/-26 Ma) of Shih et al., 2009 [2]. The Sm-Nd data form at statistically significant isochron (Fig. 1) that is controlled largely by leachate-residue pairs (samples with the R suffix are residues after leaching in cold 2N HCl for 10 minutes).

  12. Using Rare Earth Element (REE) tracers to identify preferential micro-sites of post-fire aeolian erosion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant communities in desert environments are spatially anisotropic and nutrient islands develop below plant canopies that enhance plant growth and reinforce the spatial anisotropy. Catastrophic disturbance that removes the vegetation such as fire or drought can result in the release of the trapped ...

  13. Albitization and redistribution of REE and Y in IOCG systems: Insights from Moonta-Wallaroo, Yorke Peninsula, South Australia

    NASA Astrophysics Data System (ADS)

    Kontonikas-Charos, Alkis; Ciobanu, Cristiana L.; Cook, Nigel J.

    2014-11-01

    Trace element concentrations, particularly rare earth elements and yttrium (REY) in feldspars and accessory minerals, have been determined in a suite of albitized igneous, metasedimentary and metasomatite rocks from the Moonta-Wallaroo district, Olympic Cu-Au Province, South Australia. Results show that changes in REY-fractionation trends and concentrations in feldspars and common accessories are associated with key textures in albite-bearing associations from different lithologies. In granitic rocks, pseudomorphic replacement of pre-existing feldspars is typified by porous albite with cleavage-oriented intergrowths of sericite and pore-attached hematite. These observations are comparable with albitization features of granitic terranes elsewhere. A mineral association (albite-sericite ± chlorite), similar to that from granitoids, is observed as pervasive spots in limestone, inferring prograde skarnoid reactions at low fluid/rock ratio in an impure carbonate. In metasedimentary and metasomatite rocks with comparable Na2O content (~ 5-6 wt.%), fine-grained granoblastic albite suggests growth under high fluid/rock ratios irrespective of lithology. In such cases, albite with the highest REY content (ΣREY ~ 200 ppm) accounts for the entire REY budget, e.g., in albite-biotite-schist with the lowest abundance of accessory minerals. Nanoscale investigation confirms this albite to be a REY carrier (elements incorporated within the crystal lattice); no pore-attached inclusions are observed. In contrast, albite with the lowest REY-concentration (~ 14 ppm) is encountered in the metasomatite. In such rocks, recording the highest ΣREY (~ 1000 ppm) in whole-rock, partitioning of REY is favoured among the abundant accessories (titanite, apatite) and calc-silicates (actinolite, clinozoisite) rather than albite. Comparable low-REY albite is also found in granitoid-derived albitite (Na2O ~ 5 wt.%), in which abundant accessories and discrete REY-minerals formed during albitization account for the high ΣREY content (~ 700 ppm) in whole rock. The role of coupled dissolution-reprecipitation reactions (CDRR) is critical for REY (re)distribution within albitized igneous rocks, where REY-release from early magmatic accessories and/or feldspars assists REY-enrichment into late albite. The presence of abundant nanopore-attached inclusions in plagioclase demonstrates the nanoscale nature of CDRR-driven albitization in granitoids, consistent with published experimental work on altered granites. Such porosity offers sites for REY entrapment seen within discrete REY-minerals in new-formed K-feldspar. Similarly, release and uptake of REY, concurrent with albitization, is seen in formation of coarser REY-minerals (xenotime, bastnäsite, synchysite) during CDRR-driven replacement of accessory Fe-Ti-oxides by symplectites of chlorite and hematite. Based on the differences identified between the albitization pathways in igneous and metasedimentary rocks, we discuss how albitization proceeds via a series of complex fluid-mineral reactions, each involving the redistribution, accumulation and retention of REY. These reactions are critical for defining the endowment and deportment of REY in rocks that have undergone sodic alteration. Contrary to previous models, albitization appears controlled by pH rather than redox conditions. Despite regional differences in local geological environment and alteration style across the Olympic Cu-Au Province, albitization, the initiation of hydrothermal alteration, is a pre-requisite stage for REY-enrichment in Iron-Oxide-Copper-Gold (IOCG) systems. REY distribution patterns in feldspars may thus have value in mineral exploration as criteria enabling alteration associated with mineralization to be distinguished from the regional background. Strong albitization without superposition of later potassic alteration may not, however, be automatically linked to the formation of giant IOCG deposits. Albitization enhances rock permeability and in a strongly faulted structural environment without a suitable trap, hydrothermal fluids may be more readily lost from the system.

  14. The pink topaz-bearing calcite, quartz, white mica veins from Ghundao Hill (North West Frontier Province, Pakistan): K/Ar age, stable isotope and REE data

    NASA Astrophysics Data System (ADS)

    Morteani, G.; Voropaev, A.

    2007-01-01

    In the area of the Ghundao Hill (Northern Frontier Province, Pakistan) an orange-yellow to cherry-red topaz is found in calcite, quartz, white mica veins crosscutting the schistosity of probably Silurian to Devonian gray limestones. Topaz with such a range of colours is traded as Imperial Topaz. Low fluorine contents of about 15 wt.%, oxygen isotope thermometry, K/Ar age determination on white mica, fluid inclusion data and mineral textures indicate that the topaz from Ghundao Hill crystallized at temperatures of about 230 °C during the Eocene Himalayan tectonothermal event and not from a late to postmagmatic granite-related fluid. The pink Topaz from Ghundao Hill shares the coexistence with carbonates, low fluorine content and a crystallization at low temperature and pressure during a regional tectonothermal event with the Imperial Topaz from Ouro Preto (Brazil) and from the Sanarka/Kamenka rivers (South Urals, Russia). The efficiency of topaz to remove fluorine from fluids at low temperature explains how topaz can be formed from metamorphic fluids that are typically poor in fluorine. High CO2 activity produced in the fluids by metamorphic decarbonatisation reactions and Al buffering by white mica prevented fluorination of carbonates stabilising topaz relative to fluorite.

  15. A Nd isotopic study of the Hamersley and Michipicoten banded iron formations - The source of REE and Fe in Archean oceans

    NASA Technical Reports Server (NTRS)

    Jacobsen, Stein B.; Pimentel-Klose, Mario R.

    1988-01-01

    A detailed Nd isotopic study of the large and well-dated Hamersley and Michipicoten banded iron formations (BIFs) has been conducted. The Hamersley BIFs (Lake Superior type) are located in the Pilbara craton of Western Australia and the Michipicoten BIFs (Algoma type) are located in the northeastern corner of Lake Superior in Ontario, Canada. Their initial epsilon(Nd) values are variable and in the range of 0 to +4. The Fe/Nd ratio in present-day hydrothermal waters and BIFs are both 100,000, suggesting that the source of much of the Fe in BIFs (and Archean seawater) was hydrothermal water circulating through Archean midocean ridge systems.

  16. Studies of transport pathways of Th, U, REE's, Ra-228, and Ra-226 from soil to farm animals. Progress report, April 1-December 31, 1983

    SciTech Connect

    Eisenbud, M.; Franca, E.P.

    1984-01-01

    This is a report on the Transport Pathways of Thorium, Uranium, Rare Earths Elements, Radium-228 and Radium-226 from Soil to Farm Animals. The investigation is taking place in the State of Minas Gerais, Brazil, where an ore body (Morro de Ferro) exists that contains about 30,000 metric tons of thorium and more than 50,000 metric tons of rare earth elements. The ore body, which is believed to be about 60 million years old, has eroded to the surface and has been inundated by ground water. Nearby farmers are cooperating in the study. The analytical procedures have been modified to adapt them to the large volumes of biological material. The soils from the farm plots have been sampled, analyzed and characterized by standard pedological methods. Analyses for most of the substances of interest have been completed in pilot samples of vegetables and cow bone.

  17. The reliability of ∼2.9 Ga old Witwatersrand banded iron formations (South Africa) as archives for Mesoarchean seawater: Evidence from REE and Nd isotope systematics

    NASA Astrophysics Data System (ADS)

    Viehmann, Sebastian; Bau, Michael; Smith, Albertus J. B.; Beukes, Nicolas J.; Dantas, Elton L.; Bühn, Bernhard

    2015-11-01

    Pure marine chemical sediments, such as (Banded) Iron Formations, (B)IFs, are archives of geochemical proxies for the composition of Precambrian seawater and may provide information about the ancient hydrosphere-atmosphere system. We here present rare earths and yttrium (REY) and high precision Sm-Nd isotope data of ∼2.90 Ga old Superior-type BIFs from the Witwatersrand Supergroup, South Africa, and compare those with data for near-contemporaneous BIFs from the correlative Pongola Supergroup (Superior-type BIF) and from the Pietersburg Greenstone Belt (Algoma-type IF), respectively. All Witwatersrand samples studied display the typical general REY distribution of Archean seawater, but their REY anomalies are less pronounced and their immobile element concentrations are higher than those of other pure (B)IFs. These observations indicate the presence of significant amounts of detrital aluminosilicates in the Witwatersrand BIFs and question the reliability of the Contorted Bed and Water Tower BIFs (Parktown Formation, West Rand Group) as archives of Mesoarchean seawater. Significant post-depositional alteration of the REY budget and the Sm-Nd isotope system is not observed. The Nd isotopic compositions of the purest BIF samples, i.e. the most reliable archives for Witwatersrand seawater, show initial εNd values between -3.95 and -2.25. This range is more negative than what is observed in ambient shales, indicating a decoupling of suspended and dissolved loads in the "near-shore" Witwatersrand Basin seawater. However, εNd range overlaps with that of the correlative Pongola BIF (Alexander et al., 2008). The deeper-water Algoma-type Pietersburg BIF shows more positive (i.e. more mantle-like) εNd2.9Ga values, supporting the hypothesis that a significant amount of its REY inventory was derived from black smoker-style, high-temperature hydrothermal fluids that had altered seafloor basalts. In marked contrast, the dissolved REY budgets (including the Nd isotopic compositions) of the Witwatersrand and Pongola seawater, however, were dominated by similar terrigenous REY sources from the Kaapvaal Craton.

  18. Physical characterization, magnetic measurements, REE geochemistry and biomonitoring of dust load accumulated during a protracted winter fog period and their implications.

    PubMed

    Chakarvorty, Munmun; Pati, Jayanta Kumar; Patil, Shiva Kumar; Shukla, Swati; Niyogi, Ambalika; Saraf, Arun Kumar

    2014-05-01

    The winter fog in India is a recurrent phenomenon for more than a decade now affecting the entire Himalayan and sub-Himalayan regions covering an area of nearly 500,000 km(2). Every winter (December-January), the air and surface transports in cities of northern India (Amritsar, New Delhi, Agra, Gwalior, Kanpur, Lucknow, and Allahabad) are severely disrupted with visibility reduced to <50 m at times. Since dust particles are known to act as nuclei for the fog formation, this study is aimed to carry out physicochemical characterization of the dust particulates accumulated during a protracted fog period from one of the severely fog affected cities of north India (Allahabad; 25°27'33.40″N-81°52'45.47″E). The dust-loaded tree leaves belonging to Ficus bengalensis and Ficus religiosa from 50 different locations between January 24 and 31, 2010 are sampled and characterized. The mass of dust, color, grain shape, size, phase constituents, and mineral magnetic parameters, such as magnetic susceptibility, SIRM, χ fd%, and S-ratio, show minor variation and the regional influence outweighs local anthropogenic contributions. The dust compositions show fractionated rare earth element pattern with a pronounced negative Eu anomaly similar to upper continental crust and further suggesting their derivation from sources located in parts of north and central India.

  19. The role of chloride-carbonate melts in the formation of sideritic carbonatites of the KARASUg FE-F-REE deposit (Tyva Republic, Russia)

    NASA Astrophysics Data System (ADS)

    Prokop'ev, I. R.; Borovikov, A. A.; Pavlova, G. G.; Borisenko, A. S.

    2014-04-01

    The authors have studied melt-fluid and fluid inclusions in quartz and fluorite of sideritic and ankerite-calcitic carbonatites of the Karasug ore field, as well as melt inclusions in apatite from granosyenites. The content of salt and fluid components in brine-melt inclusions was evaluated on the basis of the thermodynamic data, the calculations of volumes and densities of the solid phases, a solution of about 50% concentration, and the gas phase of the inclusions, as well as the results of the LA-ICP-MS analysis. The content of salt phases, the solution, and the gas phase amounted to 85-70, 10-25, and about 5% of the inclusion substance, respectively. The total percentage of salt and fluid components (H2O and CO2) amounted to 90-80 and 10-20 wt %, respectively. The fraction of a carbonate constituent in the inclusions was as high as 45-50% and over in ankerite-calcite carbonatites and about 15 wt % in sideritic carbonatites. The 117.2 ± 1.3 Ma age of these carbonatites by 40Ar/39Ar, along with other datings for this area, shows that their formation was associated with a manifestation of the Cretaceous alkaline-mafic magmatism (117-120 Ma). The presented model of the formation of carbonatites is in agreement with the sequence of the development of magmatic processes and mineralization in this area. The model is also confirmed by the results of the studies of melt and fluid inclusions in minerals.

  20. REE Sorption Study for Media #1 and Media #2 in Brine #1 and #2 at different Liquid to Solid Ratio's at Ambient Temperature

    DOE Data Explorer

    Gary Garland

    2015-03-27

    This data set shows the different loading capacities of Media #1 and Media #2 in a high and low salt content brine matrix at different liquid to solid ratio's. These data sets are shaker bath tests on media #1 and media #2 in brine's #1 and #2 at 500mL-.5g(1000-1 ratio), 150mL-.75g(200-1 ratio), and 150mL-2.5g(60-1 ratio) at ambient temperature.

  1. Nursing: Evidence-Based Practice Skills Nursing: Evidence-Based Practice Skills Karen Holland and Colin Rees Oxford University Press £21.99 320 pp 9780199563104 0199563101 [Formula: see text].

    PubMed

    2011-07-01

    STUDENTS, NEWLY qualified nurses and those undertaking post-registration studies will find this book a useful introduction to evidence-based practice. it is well written and simple to understand, and its authors have adopted a balanced approach to the subject.

  2. Retraction notice to "Effects of organic ligands on fractionation of rare earth elements (REEs) in hydroponic plants: An application to the determination of binding capacities by humic acid for modeling" [Chemosphere 65(11) (2006) 1942-1948].

    PubMed

    Ding, Shiming; Liang, Tao; Zhang, Chaosheng; Yan, Juncai; Zhang, Zili

    2010-08-10

    Reason: This article has been retracted, please see Elsevier Policy on Article Withdrawal:http://www.elsevier.com/locate/withdrawalpolicy This article has been retracted at the request of the editor as the authors have plagiarized part of papers that had already appeared in Chem. Geol. 209 (2004) 271-294, doi:10.1016/j.chemgeo.2004.06.012 and Geochim. Cosmochim. Acta 67 (2003) 2321-2339, doi:10.1016/S0016-7037(02)01413-8. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and we apologize to readers of the journal that this was not detected during the submission process.

  3. State of rare earth elements in different environmental components in mining areas of China.

    PubMed

    Liang, Tao; Li, Kexin; Wang, Lingqing

    2014-03-01

    China has relatively abundant rare earth elements (REEs) reserves and will continue to be one of the major producers of REEs for the world market in the foreseeable future. However, due to the large scale of mining and refining activities, large amounts of REEs have been released to the surrounding environment and caused harmful effects on local residents. This paper summarizes the data about the contents and translocation of REEs in soils, waters, atmosphere, and plants in REE mining areas of China and discusses the characteristics of their forms, distribution, fractionation, and influencing factors. Obviously high concentrations of REEs with active and bioavailable forms are observed in all environmental media. The mobility and bioavailability of REEs are enhanced. The distribution patterns of REEs in soils and water bodies are all in line with their parent rocks. Significant fractionation phenomenon among individual members of REEs was found in soil-plant systems. However, limited knowledge was available for REEs in atmosphere. More studies focusing on the behavior of REEs in ambient air of REE mining areas in China are highly suggested. In addition, systematic study on the translocation and circulation of REEs in various media in REEs mining areas and their health risk assessment should be carried out. Standard analytical methods of REEs in environments need to be established, and more specific guideline values of REEs in foods should also be developed.

  4. Geochemistry of some rare earth elements in groundwater, Vierlingsbeek, The Netherlands.

    PubMed

    Janssen, René P T; Verweij, Wilko

    2003-03-01

    Groundwater samples were taken from seven bore holes at depths ranging from 2 to 41m nearby drinking water pumping station Vierlingsbeek, The Netherlands and analysed for Y, La, Ce, Pr, Nd, Sm and Eu. Shale-normalized patterns were generally flat and showed that the observed rare earth elements (REE) were probably of natural origin. In the shallow groundwaters the REEs were light REE (LREE) enriched, probably caused by binding of LREEs to colloids. To improve understanding of the behaviour of the REE, two approaches were used: calculations of the speciation and a statistical approach. For the speciation calculations, complexation and precipitation reactions including inorganic and dissolved organic carbon (DOC) compounds, were taken into account. The REE speciation showed REE(3+), REE(SO(4))(+), REE(CO(3))(+) and REE(DOC) being the major species. Dissolution of pure REE precipitates and REE-enriched solid phases did not account for the observed REEs in groundwater. Regulation of REE concentrations by adsorption-desorption processes to Fe(III)(OH)(3) and Al(OH)(3) minerals, which were calculated to be present in nearly all groundwaters, is a probable explanation. The statistical approach (multiple linear regression) showed that pH is by far the most significant groundwater characteristic which contributes to the variation in REE concentrations. Also DOC, SO(4), Fe and Al contributed significantly, although to a much lesser extent, to the variation in REE concentrations. This is in line with the calculated REE-species in solution and REE-adsorption to iron and aluminium (hydr)oxides. Regression equations including only pH, were derived to predict REE concentrations in groundwater. External validation showed that these regression equations were reasonably successful to predict REE concentrations of groundwater of another drinking water pumping station in quite different region of The Netherlands.

  5. Interactions of microorganisms with rare earth ions and their utilization for separation and environmental technology.

    PubMed

    Moriwaki, Hiroshi; Yamamoto, Hiroki

    2013-01-01

    In recent years, rare earth elements (REEs) have been widely used in various modern technological devices and the global demand for REE has been increasing. The increased demand for REEs has led to environmental exposure or water pollution from rare earth metal mines and various commercial products. Therefore, the development of a safe technology for the separation and adsorption of REEs is very important from the perspective of green chemistry and environmental pollution. In this review, the application and mechanisms of microorganisms for the removal and extraction of REEs from aqueous solutions are described. In addition, the advantages in using microorganisms for REE adsorption and future studies on this topic are discussed.

  6. Studies of rare earth element distribution and action in human erythrocyte and animal hepatocyte by PIXE

    NASA Astrophysics Data System (ADS)

    Wu, Y. P.; Mi, Y.; Shen, H.; Yao, H. Y.; Cheng, Y.; Wang, X.; Zhang, J. X.

    2002-04-01

    PIXE analysis is applied to investigate a long-term disputed issue whether the rare earth element (REE) can enter the cell across the cell membrane or not. It has been illustrated that REE could travel across the biomembrane into the cells by cell studies in vitro as well as in studies of animals fed with REEs diet. The binding of REE by membrane changes its permeability and makes intracellular ion transportable. Entrance of REEs may influence the cellular function. In addition, the REE distribution and behavior in cell are discussed.

  7. Recovery and Separation of Rare Earth Elements Using Salmon Milt

    PubMed Central

    Takahashi, Yoshio; Kondo, Kazuhiro; Miyaji, Asami; Watanabe, Yusuke; Fan, Qiaohui; Honma, Tetsuo; Tanaka, Kazuya

    2014-01-01

    Recycling rare earth elements (REEs) used in advanced materials such as Nd magnets is important for the efficient use of REE resources when the supply of several REEs is limited. In this work, the feasibility of using salmon milt for REE recovery and separation was examined, along with the identification of the binding site of REEs in salmon milt. Results showed that (i) salmon milt has a sufficiently high affinity to adsorb REEs and (ii) the adsorption capacity of the milt is 1.04 mEq/g, which is comparable with that of commercial cation exchange resin. Heavier REEs have higher affinity for milt. A comparison of stability constants and adsorption patterns of REEs discussed in the literature suggests that the phosphate is responsible for the adsorption of REE in milt. The results were supported by dysprosium (Dy) and lutetium (Lu) LIII-edge extended x-ray absorption fine structure (EXAFS) spectroscopy. The REE-P shell was identified for the second neighboring atom, which shows the importance of the phosphate site as REE binding sites. The comparison of REE adsorption pattern and EXAFS results between the milt system and other adsorbent systems (cellulose phosphate, Ln-resin, bacteria, and DNA-filter hybrid) revealed that the coordination number of phosphate is correlated with the slope of the REE pattern. The separation column loaded with milt was tested to separate REE for the practical use of salmon milt for the recovery and separation of REE. However, water did not flow through the column possibly because of the hydrophobicity of the milt. Thus, sequential adsorption–desorption approach using a batch-type method was applied for the separation of REE. As an example of the practical applications of REE separation, Nd and Fe(III) were successfully separated from a synthetic solution of Nd magnet waste by a batch-type method using salmon milt. PMID:25490035

  8. Health effects and toxicity mechanisms of rare earth elements-Knowledge gaps and research prospects.

    PubMed

    Pagano, Giovanni; Guida, Marco; Tommasi, Franca; Oral, Rahime

    2015-05-01

    In the recent decades, rare earth elements (REE) have undergone a steady spread in several industrial and medical applications, and in agriculture. Relatively scarce information has been acquired to date on REE-associated biological effects, from studies of bioaccumulation and of bioassays on animal, plant and models; a few case reports have focused on human health effects following occupational REE exposures, in the present lack of epidemiological studies of occupationally exposed groups. The literature is mostly confined to reports on few REE, namely cerium and lanthanum, whereas substantial information gaps persist on the health effects of other REE. An established action mechanism in REE-associated health effects relates to modulating oxidative stress, analogous to the recognized redox mechanisms observed for other transition elements. Adverse outcomes of REE exposures include a number of endpoints, such as growth inhibition, cytogenetic effects, and organ-specific toxicity. An apparent controversy regarding REE-associated health effects relates to opposed data pointing to either favorable or adverse effects of REE exposures. Several studies have demonstrated that REE, like a number of other xenobiotics, follow hormetic concentration-related trends, implying stimulatory or protective effects at low levels, then adverse effects at higher concentrations. Another major role for REE-associated effects should be focused on pH-dependent REE speciation and hence toxicity. Few reports have demonstrated that environmental acidification enhances REE toxicity; these data may assume particular relevance in REE-polluted acidic soils and in REE mining areas characterized by concomitant REE and acid pollution. The likely environmental threats arising from REE exposures deserve a new line of research efforts.

  9. Uptake of Germanium and Rare Earth Elements (La, Gd, Er, Nd) by white mustard (Brassica alba L.) and common millet (Panicum milliaceum L.) as affected by Phosphorus Nutrition

    NASA Astrophysics Data System (ADS)

    Zill, Juliane; Wiche, Oliver

    2015-04-01

    The effect of phosphate nutrition is important due to the future usage of fertilizer treatment in phytomining experiments e.g. in accumulation of the economically important rare earth elements (REE). It is expected that the trivalent charge of REE will result in complexation with phosphate and REEs could be immobilized and not further bioavailable for plants which would cause losses of REE concentration in biomass. To investigate this influence on lanthanum, neodymium, gadolinium and erbium two plant species Brassica alba (white mustard) and Panicum miliaceum (common millet) were cultured in a greenhouse study. The plants were cultivated onto two different substrates and were poured with modified REE and phosphate solutions within an eight-week period. The concentrations of REE in soil, soil solution and plant samples were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The results show an increase of concentration of REE with increasing levels of element solution applied for both species. REE accumulations are elevated in roots and decrease in the order of roots> leaves> stem> fruit/blossom. Brassica accumulated more REE in root whereas Panicum showed higher REE concentrations in leaves. Exposure to increased phosphate addition did not significantly change the concentrations of REE in both plant species yet the REE concentrations in leaves slightly decreased with increasing phosphate addition. For root and stem no precise trend could be determined. It is most likely that REEs precipitate with phosphate on root surfaces and in the roots. The bioavailability of REE to plants is affected by complexation processes of REEs with phosphate in the rhizosphere. The results indicate that phosphate application plays an important role on REE uptake by roots and accumulation in different parts of a plant and it might have an influence on translocation of REE within the plant.

  10. Distribution pattern of rare earth ions between water and montmorillonite and its relation to the sorbed species of the ions.

    PubMed

    Takahashi, Yoshio; Tada, Akisa; Shimizu, Hiroshi

    2004-09-01

    REE (rare earth element) distribution coefficients (Kd) between the aqueous phase and montmorillonite surface were obtained to investigate the relation between the REE distribution patterns and the species of REE sorbed on the solid-water interface. It was shown that the features in the REE patterns, such as the slope of the REE patterns, the tetrad effect, and the Y/Ho ratio, were closely related to the REE species at the montmorillonite-water interface. In a binary system (REE-montmorillonite) below pH 5, three features (a larger Kd value for a lighter REE, the absence of the tetrad effect, and the Y/Ho ratio being unchanged from its initial value) suggest that hydrated REE are directly sorbed as an outer-sphere complex at the montmorillonite-water interface. Above pH 5.5, the features in the REE patterns, the larger Kd value for heavier REE, the M-type tetrad effect, and the reduced Y/Ho ratio, showed the formation of an inner-sphere complex of REE with -OH group at the montmorillonite surface. In addition, the REE patterns in the presence of humic acid at pH 5.9 were also studied, where the REE patterns became flat, suggesting that the humate complex is dominant as both dissolved and sorbed species of REE in the ternary system. All of these results were consistent with the spectroscopic data (laser-induced fluorescence spectroscopy) showing the local structure of Eu(III) conducted in the same experimental system. The present results suggest that the features in the REE distribution patterns include information on the REE species at the solid-water interface.

  11. Rare earth elements in human hair from a mining area of China.

    PubMed

    Wei, Binggan; Li, Yonghua; Li, Hairong; Yu, Jiangping; Ye, Bixiong; Liang, Tao

    2013-10-01

    Rare earth minerals have been mined for more than 50 years in Inner Mongolia of China. In the mining area rare earth elements (REE) may be significantly accumulated in humans. Therefore, the aim of this paper is to characterize the REE concentrations in hair of local residents. REE concentrations in hair of 118 subjects were determined. The results showed that the mean concentrations of the determined REE in the hair of both females and males were usually higher from mining area than from control area. The mean concentrations of all the fifteen REE were much higher in hair of males than in hair of females from mining area. This suggested that males might be more sensitive to REE than females. In addition, the mean contents of the REE in hair of miners, particularly light REE (La, Ce, Pr and Nd), were usually much higher than the values in hair of non-miners from both mining area and control area, indicating that the miners were exposed to higher concentrations of REE in occupational environment. Among age groups, the relationships between REE concentrations and age groups showed that more and more concentrations of light REE accumulated in body of both females and males with age until 60 years, while heavy REE concentrations decreased with age in males who were exposed to low concentrations of heavy REE.

  12. Bacterial Cell Surface Adsorption of Rare Earth Elements

    NASA Astrophysics Data System (ADS)

    Jiao, Y.; Park, D.; Reed, D.; Fujita, Y.; Yung, M.; Anderko, A.; Eslamimanesh, A.

    2015-12-01

    Rare earth elements (REE) play a critical role in many emerging clean energy technologies, including high-power magnets, wind turbines, solar panels, hybrid/electric vehicle batteries and lamp phosphors. In order to sustain demand for such technologies given current domestic REE shortages, there is a need to develop new approaches for ore processing/refining and recycling of REE-containing materials. To this end, we have developed a microbially-mediated bioadsorption strategy with application towards enrichment of REE from complex mixtures. Specifically, the bacterium Caulobacter crescentus was genetically engineered to display lanthanide binding tags (LBTs), short peptides that possess high affinity and specificity for rare earth elements, on its cell surface S-layer protein. Under optimal conditions, LBT-displayed cells adsorbed greater than 5-fold more REE than control cells lacking LBTs. Competition binding experiments with a selection of REEs demonstrated that our engineered cells could facilitate separation of light- from heavy- REE. Importantly, binding of REE onto our engineered strains was much more favorable compared to non-REE metals. Finally, REE bound to the cell surface could be stripped off using citrate, providing an effective and non-toxic REE recovery method. Together, this data highlights the potential of our approach for selective REE enrichment from REE containing mixtures.

  13. High Tc composite silver/oxide superconductors

    NASA Technical Reports Server (NTRS)

    Curreri, P. A.; Peters, P. N.; Sisk, R. C.; Wu, M. K.; Huang, C. Y.

    1990-01-01

    Factors involved in the strong flux pinning effect of high-Tc YBa2Cu3O7/AgO (Y-123/AgO) composite and other REE-123/AgO composites were investigated. Samples of superconducting REE-123 and REE-123/AgO (where REE was Nd, Sm, Eu, Gd, Dy, Ho, Er, or Y) were prepared and used to obtain magnetic moments, critical field, and microstructure data. The optimum heat treatment conditions for the formation of strong flux-pinning REE-123/AgO composites were found to be different for different REE-123 compounds. It was found that the annealing temperature depends on the ionic size of the REE, with larger rare-earth ions requiring higher temperature. It was also found that strong flux-pinning REE-123/AgO composites form only in a narrow annealing temperature range.

  14. The rare-earth elements: vital to modern technologies and lifestyles

    USGS Publications Warehouse

    Van Gosen, Bradley S.; Verplanck, Philip L.; Long, Keith R.; Gambogi, Joseph; Seal, Robert R., II

    2014-01-01

    Since the late 1990s, China has provided 85–95 percent of the world’s REEs. In 2010, China announced their intention to reduce REE exports. During this timeframe, REE use increased substantially. REEs are used as components in high technology devices, including smart phones, digital cameras, computer hard disks, fluorescent and light-emitting-diode (LED) lights, flat screen televisions, computer monitors, and electronic displays. Large quantities of some REEs are used in clean energy and defense technologies. Because of the many important uses of REEs, nations dependent on new technologies, such as Japan, the United States, and members of the European Union, reacted with great concern to China’s intent to reduce its REE exports. Consequently, exploration activities intent on discovering economic deposits of REEs and bringing them into production have increased.

  15. Hydrothermal transport and deposition of the rare earth elements by fluorine-bearing aqueous liquids

    NASA Astrophysics Data System (ADS)

    Migdisov, Art A.; Williams-Jones, A. E.

    2014-12-01

    New technologies, particularly those designed to address environmental concerns, have created a great demand for the rare earth elements (REE), and focused considerable attention on the processes by which they are concentrated to economically exploitable levels in the Earth's crust. There is widespread agreement that hydrothermal fluids played an important role in the formation of the world's largest economic REE deposit, i.e. Bayan Obo, China. Until recently, many researchers have assumed that hydrothermal transport of the REE in fluorine-bearing ore-forming systems occurs mainly due to the formation of REE-fluoride complexes. Consequently, hydrothermal models for REE concentration have commonly involved depositional mechanisms based on saturation of the fluid with REE minerals due to destabilization of REE-fluoride complexes. Here, we demonstrate that these complexes are insignificant in REE transport, and that the above models are therefore flawed. The strong association of H+ and F- as HF° and low solubility of REE-F solids greatly limit transport of the REE as fluoride complexes. However, this limitation does not apply to REE-chloride complexes. Because of this, the high concentration of Cl- in the ore fluids, and the relatively high stability of REE-chloride complexes, the latter can transport appreciable concentrations of REE at low pH. The limitation also does not apply to sulphate complexes and in some fluids, the concentration of sulphate may be sufficient to transport significant concentrations of REE as sulphate complexes, particularly at weakly acidic pH. This article proposes new models for hydrothermal REE deposition based on the transport of the REE as chloride and sulphate complexes.

  16. Evaluation of Tests of Perceptual Speed/Accuracy and Spatial Ability for Use in Military Occupational Classification

    DTIC Science & Technology

    2014-08-22

    e.g., Ree & Carretta, 1994), a strong general factor for the ASVAB dominated by the verbal and math tests, which they interpreted as crys- tallized...content have been a mainstay of multi- ple aptitude aircrew test batteries (Carretta & Ree , 2003) such as the Air Force Officer Qual- ifying Test...Drasgow, Nye, Carretta, & Ree , 2010) and other aircrew aptitude batteries (Car- retta & Ree , 2003) for many years, as well as periodically appearing on

  17. Geology and market-dependent significance of rare earth element resources

    NASA Astrophysics Data System (ADS)

    Simandl, G. J.

    2014-12-01

    China started to produce rare earth elements (REEs) in the 1980s, and since the mid-1990s, it has become the dominant producer. Rare earth element export quotas first introduced by the Chinese government in the early 2000s were severely reduced in 2010 and 2011. This led to strong government-created disparity between prices within China and the rest of the world. Industrialized countries identified several REEs as strategic metals. Because of rapid price increases of REE outside of China, we have witnessed a world-scale REE exploration rush. The REE resources are concentrated in carbonatite-related deposits, peralkaline igneous rocks, pegmatites, monazite ± apatite veins, ion adsorption clays, placers, and some deep ocean sediments. REE could also be derived as a by-product of phosphate fertilizer production, U processing, mining of Ti-Zr-bearing placers, and exploitation of Olympic Dam subtype iron oxide copper gold (IOCG) deposits. Currently, REEs are produced mostly from carbonatite-related deposits, but ion adsorption clay deposits are an important source of heavy REE (HREE). Small quantities of REE are derived from placer deposits and one peralkaline intrusion-related deposit. The ideal REE development targets would be located in a politically stable jurisdiction with a pro-mining disposition such as Canada and Australia. REE grade, HREE/light REE (LREE) ratio of the mineralization, tonnage, mineralogy, and permissive metallurgy are some of the key technical factors that could be used to screen potential development projects. As REEs are considered strategic metals from economic, national security, and environmental points of view, technical and economic parameters alone are unlikely to be used in REE project development decision-making. Recycling of REE is in its infancy and unless legislated, in the short term, it is not expected to contribute significantly to the supply of REE.

  18. Repetitive Regeneration of Media #1 in a Dynamic Column Extraction using Brine #1

    SciTech Connect

    Gary Garland

    2015-10-14

    This data is from a regeneration study from a dynamic column extraction experiment where we ran a solution of REE's through a column of media #1 then stripped the REE's off the media using 2M HNO3 solution. We then re-equilibrated the media and repeated the process of running a REE solution through the column and stripping the REE's off the media and comparing the two runs.

  19. Human and Financial Capital in the Rural Educational Environment: The Effects of Exceeding the Carrying Capacity Threshold on Standardized Test Scores in Rural Indiana.

    ERIC Educational Resources Information Center

    Peoples, Glenn

    The Rural Educational Environment (REE) is a complex mixture of demographic and economic forces that interact to impact the rural school corporation. The condition of REE financial and human capital indicates REE health and may influence student performance on standardized tests. This paper proposes an ecosystem model of the impact of financial,…

  20. Growth Failure in Children with Intractable Epilepsy Is Not Due to Increased Resting Energy Expenditure

    ERIC Educational Resources Information Center

    Bergqvist, A. G. Christina; Trabulsi, Jillian; Schall, Joan I.; Stallings, Virginia A.

    2008-01-01

    The aim of this study was to evaluate the resting energy expenditure (REE) of children with intractable epilepsy (IE) compared with healthy children, and to determine factors that contribute to the pattern of REE. REE, growth status, and body composition were assessed in 25 prepubertal children with IE (15 males, 10 females; mean age 5y 5mo [SD 2y…

  1. Selective Extraction of Rare Earth Elements from Permanent Magnet Scraps with Membrane Solvent Extraction

    SciTech Connect

    Kim, Daejin; Powell, Lawrence E.; Delmau, Lætitia H.; Peterson, Eric S.; Herchenroeder, Jim; Bhave, Ramesh R.

    2015-06-24

    In this paper, the rare earth elements (REEs) such as neodymium, praseodymium, and dysprosium were successfully recovered from commercial NdFeB magnets and industrial scrap magnets via membrane assisted solvent extraction (MSX). A hollow fiber membrane system was evaluated to extract REEs in a single step with the feed and strip solutions circulating continuously through the MSX system. The effects of several experimental variables on REE extraction such as flow rate, concentration of REEs in the feed solution, membrane configuration, and composition of acids were investigated with the MSX system. A multimembrane module configuration with REEs dissolved in aqueous nitric acid solutions showed high selectivity for REE extraction with no coextraction of non-REEs, whereas the use of aqueous hydrochloric acid solution resulted in coextraction of non-REEs due to the formation of chloroanions of non-REEs. The REE oxides were recovered from the strip solution through precipitation, drying, and annealing steps. Finally, the resulting REE oxides were characterized with XRD, SEM-EDX, and ICP-OES, demonstrating that the membrane assisted solvent extraction is capable of selectively recovering pure REEs from the industrial scrap magnets.

  2. Selective Extraction of Rare Earth Elements from Permanent Magnet Scraps with Membrane Solvent Extraction

    DOE PAGES

    Kim, Daejin; Powell, Lawrence E.; Delmau, Lætitia H.; ...

    2015-06-24

    In this paper, the rare earth elements (REEs) such as neodymium, praseodymium, and dysprosium were successfully recovered from commercial NdFeB magnets and industrial scrap magnets via membrane assisted solvent extraction (MSX). A hollow fiber membrane system was evaluated to extract REEs in a single step with the feed and strip solutions circulating continuously through the MSX system. The effects of several experimental variables on REE extraction such as flow rate, concentration of REEs in the feed solution, membrane configuration, and composition of acids were investigated with the MSX system. A multimembrane module configuration with REEs dissolved in aqueous nitric acidmore » solutions showed high selectivity for REE extraction with no coextraction of non-REEs, whereas the use of aqueous hydrochloric acid solution resulted in coextraction of non-REEs due to the formation of chloroanions of non-REEs. The REE oxides were recovered from the strip solution through precipitation, drying, and annealing steps. Finally, the resulting REE oxides were characterized with XRD, SEM-EDX, and ICP-OES, demonstrating that the membrane assisted solvent extraction is capable of selectively recovering pure REEs from the industrial scrap magnets.« less

  3. Global demand for rare earth resources and strategies for green mining

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rare earths elements (REEs) are essential raw materials for the emerging green (low-carbon) energy technologies and ‘smart’ electronic devices. Global REE demand is slated to grow at a compound annual rate of 5% by 2020. Such high growth rate would require a steady supply base of REEs in the long ru...

  4. 7 CFR 550.26 - Monitoring program performance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... policies, as long as they are consistent with REE requirements. However, in order to fulfill their role in... information available to the REE Agency. It is the responsibility of the Cooperator to ensure that the project... project or activity will continue for as long as the REE Agency retains a financial interest in...

  5. Selective Extraction of Rare Earth Elements from Permanent Magnet Scraps with Membrane Solvent Extraction.

    PubMed

    Kim, Daejin; Powell, Lawrence E; Delmau, Lætitia H; Peterson, Eric S; Herchenroeder, Jim; Bhave, Ramesh R

    2015-08-18

    The rare earth elements (REEs) such as neodymium, praseodymium, and dysprosium were successfully recovered from commercial NdFeB magnets and industrial scrap magnets via membrane assisted solvent extraction (MSX). A hollow fiber membrane system was evaluated to extract REEs in a single step with the feed and strip solutions circulating continuously through the MSX system. The effects of several experimental variables on REE extraction such as flow rate, concentration of REEs in the feed solution, membrane configuration, and composition of acids were investigated with the MSX system. A multimembrane module configuration with REEs dissolved in aqueous nitric acid solutions showed high selectivity for REE extraction with no coextraction of non-REEs, whereas the use of aqueous hydrochloric acid solution resulted in coextraction of non-REEs due to the formation of chloroanions of non-REEs. The REE oxides were recovered from the strip solution through precipitation, drying, and annealing steps. The resulting REE oxides were characterized with XRD, SEM-EDX, and ICP-OES, demonstrating that the membrane assisted solvent extraction is capable of selectively recovering pure REEs from the industrial scrap magnets.

  6. The future of rare earth elements—will these high-tech industry elements continue in short supply?

    USGS Publications Warehouse

    Long, Keith R.

    2011-01-01

    * REE will continue to find increasing use due to their unique properties. * There is a realistic possibility around 2015-2016 of sufficient REE capacity to meet demand under conditions of healthy price competition. * REE supplies will be tight and prices high for a few years. * There is significant downside risk that newly developed mines will not perform as planned.

  7. 7 CFR 550.16 - Project development.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... that contribute to REE program objectives and help carry out the REE mission. The Cooperator's PI and... Cooperator's PI and the awarding Agency's ADODR consisting of the following: (1) Objective (2) Approach (3... shall be jointly developed by the REE ADODR and the Cooperator PI outlining the following...

  8. Metal loading effect on rare earth element binding to humic acid: Experimental and modelling evidence

    NASA Astrophysics Data System (ADS)

    Marsac, Rémi; Davranche, Mélanie; Gruau, Gérard; Dia, Aline

    2010-03-01

    The effect of metal loading on the binding of rare earth elements (REE) to humic acid (HA) was studied by combining ultrafiltration and Inductively Coupled Plasma Mass Spectrometry techniques. REE-HA complexation experiments were performed at pH 3 for REE/C molar ratios ranging from ca 4 × 10 -4 to 2.7 × 10 -2. Results show that the relative amount of REE bound to HA strongly increases with decreasing REE/C. A middle-REE (MREE) downward concavity is shown by patterns at high metal loading, whereas patterns at low metal loading display a regular increase from La to Lu. Humic Ion Model VI modelling are close to the experimental data variations, provided that (i) the ΔLK 2 parameter (i.e. the Model VI parameter taken into account the presence of strong but low density binding sites) is allowed to increase regularly from La to Lu (from 1.1 to 2.1) and (ii) the published log KMA values (i.e. the REE-HA binding constants specific to Model VI) are slightly modified, in particular with respect to heavy REE. Modelling approach provided evidence that logKdREE patterns with varying REE/C likely arises because REE binding to HA occurs through two types of binding sites in different density: (i) a few strong sites that preferentially complex the heavy REE and thus control the logKdREE atterns at low REE/C; (ii) a larger amount of weaker binding sites that preferentially complex the middle-REE and thus control the logKdREE pattern at high REE/C. Hence, metal loading exerts a major effect on HA-mediated REE binding, which could explain the diversity of published conditional constants for REE binding with HA. A literature survey suggests that the few strong sites activated at low REE/C could be multidentate carboxylic sites, or perhaps N-, or P-functional groups. Finally, an examination of the literature field data proposed that the described loading effect could account for much of the variation in REE patterns observed in natural organic-rich waters (DOC > 5 mg L -1 and 4

  9. Geochemical investigation of Archaean Bimodal and Dwalile metamorphic suites, Ancient Gneiss Complex, Swaziland

    USGS Publications Warehouse

    Hunter, D.R.; Barker, F.; Millard, H.T.

    1984-01-01

    The bimodal suite (BMS) comprises leucotonalitic and trondhjemitic gneisses interlayered with amphibolites. Based on geochemical parameters three main groups of siliceous gneiss are recognized: (i) SiO2 14%, and fractionated light rare-earth element (REE) and flat heavy REE patterns; (ii) SiO2 and Al2O3 contents similar to (i) but with strongly fractionated REE patterns with steep heavy REE slopes; (iii) SiO2 > 73%, Al2O3 < 14%, Zr ??? 500 ppm and high contents of total REE having fractionated light REE and flat heavy REE patterns with large negative Eu anomalies. The interlayered amphibolites have major element abundances similar to those of basaltic komatiites, Mg-tholeiites and Fe-rich tholeiites. The former have gently sloping REE patterns, whereas the Mg-tholeiites have non-uniform REE patterns ranging from flat (??? 10 times chondrite) to strongly light REE-enriched. The Fe-rich amphibolites have flat REE patterns at 20-30 times chondrite. The Dwalile metamorphic suite, which is preserved in the keels of synforms within the BMS, includes peridotitic komatiites that have depleted light REE patterns similar to those of compositionally similar volcanics in the Onverwacht Group, Barberton, basaltic komatiites and tholeiites. The basaltic komatiites have REE patterns parallel to those of the BMS basaltic komatiites but with lower total REE contents. The Dwalile tholeiites have flat REE patterns. The basic and ultrabasic liquids were derived by partial melting of a mantle source which may have been heterogeneous or the heterogeneity may have resulted from sequential melting of the mantle source. The Fe-rich amphibolites were derived either from liquids generated at shallow levels or from liquids generated at depth which subsequently underwent extensive fractionation. ?? 1984.

  10. Resting energy expenditure among Japanese.

    PubMed

    Hosoya, N; Mitsuhashi, F; Sugiyama, M

    2002-10-01

    1. Resting energy expenditure (REE) provides appropriate basic data for the calculation of energy requirements. 2. The REE of 6498 subjects according to sex and age (1 year stratification), with a minimum of 10 subjects per group, was measured systematically using the easy portable calorimeter (Metavine; Vine, Tokyo, Japan). 3. The REE or the REE/kg according to age and sex was observed to obtain the amount of standard deviation (20-25%). 4. The REE/kg for male and female subjects was maintained at a steady level after the age of 15 years and was estimated to be around 29 kcal/kg.

  11. Rare earth element patterns in biotite, muscovite and tourmaline minerals

    SciTech Connect

    Laul, J.C.; Lepel, E.A.

    1986-04-21

    Rare earth element concentrations in the minerals biotite and muscovite from the mica schist country rocks of the Etta pegmatite and tourmalines from the Bob Ingersoll pegmatite have been measured by INAA and CNAA. The concentrations range from 10/sup -4/ g/g to 10/sup -10g//sub g/. The REE patterns of biotite, muscovite and tourmaline reported herein are highly fractionated from light to heavy REE. The REE concentrations in biotite and muscovite are high and indigenous. The pegmatite tourmalines contain low concentrations of REE. Variations in tourmaline REE patterns reflect the geochemical evolution of pegmatite melt/fluid system during crystallization.

  12. Hydroxylamine hydrochloride-acetic acid-soluble and -insoluble fractions of pelagic sediment: Readsorption revisited

    USGS Publications Warehouse

    Piper, D.Z.; Wandless, G.A.

    1992-01-01

    The extraction of the rare earth elements (REE) from deep-ocean pelagic sediment, using hydroxylamine hydrochloride-acetic acid, leads to the separation of approximately 70% of the bulk REE content into the soluble fraction and 30% into the insoluble fraction. The REE pattern of the soluble fraction, i.e., the content of REE normalized to average shale on an element-by-element basis and plotted against atomic number, resembles the pattern for seawater, whereas the pattern, as well as the absolute concentrations, in the insoluble fraction resembles the North American shale composite. These results preclude significant readsorption of the REE by the insoluble phases during the leaching procedure.

  13. Rare-Earth Elements in Lighting and Optical Applications and Their Recycling

    NASA Astrophysics Data System (ADS)

    Song, Xin; Chang, Moon-Hwan; Pecht, Michael

    2013-10-01

    Rare-earth elements (REEs) are used in lighting and optical applications to enable color and light adjustment, miniaturization, and energy efficiency. Common applications of REEs include phosphors for light-emitting diodes, lasers, and electronic video displays. This article reviews how REEs are widely used in these applications. However, supply constraints, including rising prices, environmental concerns over mining and refining processes, and China's control over the supply of the vast majority of REEs, are of concern for manufacturers. In view of these supply constraints, this article discusses ways for manufacturers of lighting and optical devices to identify potential substitutes and recycling methods for REEs.

  14. Separation/Preconcentration Techniques for Rare Earth Elements Analysis

    NASA Astrophysics Data System (ADS)

    Hu, Bin; He, Man; Chen, Beibei; Jiang, Zucheng

    2016-10-01

    The main aim of this chapter exactly characterizes the contribution. The analytical chemistry of the rare earth elements (REEs) very often is highly complicated and the determination of a specific element is impossible without a sample pre-concentration. Sample preparation can be carried out either by separation of the REEs from the matrix or by concentrating the REEs. The separation of REEs from each other is mainly made by chromatography. At the beginning of REE analysis, the method of precipitation/coprecipitation was applied for the treatment of REE mixtures. The method is not applicable for the separation of trace amounts of REEs. The majority of the methods used are based on the distribution of REEs in a two-phase system, a liquid-liquid or a liquid-solid system. Various techniques have been developed for the liquid-liquid extraction (LLE), in particular the liquid phase micro-extraction. The extraction is always combined with a pre-concentration of the REEs in a single drop of extractant or in a hollow fiber filled with the extractant. Further modified techniques for special applications and for difficult REE separation have been developed. Compared to the LLE, the solid phase micro-extraction is preferred. The method is robust and easy to handle, in which the solid phase loaded with the REEs can be used directly for subsequent determination methods. At present, very new solid materials, like nanotubes, are developed and tested for solid phase extraction.

  15. Rare earth elements and hypertension risk among housewives: A pilot study in Shanxi Province, China.

    PubMed

    Wang, Bin; Yan, Lailai; Huo, Wenhua; Lu, Qun; Cheng, Zixi; Zhang, Jingxu; Li, Zhiwen

    2017-01-01

    Studies have shown that residents living near rare earth mining areas have high concentrations of rare earth elements (REEs) in their hair. However, the adverse effects of REEs on human health have rarely been the focus of epidemiological studies. The goal of this study was to evaluate the relationship between REEs in hair and the risk of hypertension in housewives. We recruited 398 housewives in Shanxi Province, China, consisting of 163 women with hypertension (cases) and 235 healthy women without hypertension (controls). We analyzed 15 REEs (lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), Yttrium (Y), cerium (Ce), praseodymium (Pr), and neodymium (Nd)) and calcium (Ca) accumulated in housewives hair over a period of two years. The results revealed that, with the exception of Eu, concentrations of the REEs in hair were higher in the cases than in the controls. The univariate odds ratios (ORs) of the 14 REEs were >1, and four of the REEs (Dy, Tm, Yb, and Y) also had adjusted ORs > 1. The increasing dose-response trends of the four REEs further indicated the potential for increased hypertension risk. Moreover, the REEs were negatively correlated with Ca content in hair. These results might suggest an antagonistic effect of REEs on Ca in the human body. It was concluded that high intake of REEs might increase the risk of hypertension among housewives.

  16. Moderate-to-high levels of exercise are associated with higher resting energy expenditure in community-dwelling postmenopausal women

    PubMed Central

    Froehle, Andrew W.; Hopkins, Susan R.; Natarajan, Loki; Schoeninger, Margaret J.

    2013-01-01

    Postmenopausal women experience an age-related decline in resting energy expenditure (REE), which is a risk factor for energy imbalance and metabolic disease. Exercise, by association with greater lean tissue mass and other factors, has the potential to mediate REE decline, but the relationship between exercise and REE in postmenopausal women is not well characterized. This study tests the hypothesis that exercise energy expenditure (EEE) is positively associated with REE, opposing the effects of age and menopause. The study tests this hypothesis in a cross-sectional sample of healthy postmenopausal women (N = 31, aged 49 - 72 years) with habitual exercise volumes at or above levels consistent with current clinical recommendations. Subjects kept four weeks of exercise diaries quantifying exercise activity, and were measured for body composition, maximal oxygen uptake, and REE. Multiple regression analysis was used to test for relationships between EEE, age, body composition, and REE. EEE and lean tissue mass (fat-free mass: FFM; and fat-free mass index: FFMI) exhibited significant, positive relationships with REE. The relationship between REE and EEE remained significant even after controlling for lean tissue mass. These results support the hypothesis that exercise is positively associated with REE, counter to the negative effects of age and menopause, and indicate a continuous relationship between exercise and REE across the moderate-to-high exercise range. Exercise at levels at and above current clinical guidelines may, in part, ameliorate risk for energy imbalance and metabolic disease through a positive relationship with REE. PMID:24053522

  17. Rare earth element distributions and fractionation in plankton from the northwestern Mediterranean Sea.

    PubMed

    Strady, Emilie; Kim, Intae; Radakovitch, Olivier; Kim, Guebuem

    2015-01-01

    Rare earth element (REE) concentrations were measured for the first time in plankton from the northwestern Mediterranean Sea. The REE concentrations in phytoplankton (60-200 μm) were 5-15 times higher than those in four size fractions of zooplankton: 200-500 μm, 500-1000 μm, 1000-2000 μm and >2000 μm. The concentrations within these zooplankton fractions exhibited the same ranges with some variation attributed to differences in zooplankton taxonomy. The REE concentrations in plankton were poorly related to the reported REE concentrations of seawater, but they correlated well with the calculated REE(3+), concentrations especially with regard to middle REE (MREEs) and heavy REEs (HREEs). Plankton and seawater revealed different PAAS-normalised REE distributions, with the greatest differences observed in the light REEs. Interestingly, a comparison of PAAS-normalized sediment particles from the study of Fowler et al. (1992) showed concentrations of the same order of magnitude and a similar REE distribution without MREE enrichment. Based on this comparison, we propose a conceptual model that emphasizes the importance of biological scavenging of REEs (especially LREEs) in surface waters.

  18. Geochemistry of rare earth elements in a passive treatment system built for acid mine drainage remediation.

    PubMed

    Prudêncio, Maria Isabel; Valente, Teresa; Marques, Rosa; Sequeira Braga, Maria Amália; Pamplona, Jorge

    2015-11-01

    Rare earth elements (REE) were used to assess attenuation processes in a passive system for acid mine drainage treatment (Jales, Portugal). Hydrochemical parameters and REE contents in water, soils and sediments were obtained along the treatment system, after summer and winter. A decrease of REE contents in the water resulting from the interaction with limestone after summer occurs; in the wetlands REE are significantly released by the soil particles to the water. After winter, a higher water dynamics favors the AMD treatment effectiveness and performance since REE contents decrease along the system; La and Ce are preferentially sequestered by ochre sludge but released to the water in the wetlands, influencing the REE pattern of the creek water. Thus, REE fractionation occurs in the passive treatment systems and can be used as tracer to follow up and understand the geochemical processes that promote the remediation of AMD.

  19. The role of phosphorus in lunar samples - A chemical study

    NASA Technical Reports Server (NTRS)

    Jovanovic, S.; Reed, G. W., Jr.

    1983-01-01

    Phases rapidly dissolved by pH1 HNO3 acid are found in up to 60% of the REE, P, U, and halogens in basalt 75055, basalt mineral separates, KREEP-rich breccia 14312, and components from highland breccia 66095. This suggests that they may be phosphates. The 0.1 M HNO3 soluble fractions from whole rock breccias 14312 and 66095, and 60095 matrix, and a melt rock clast, have similar REE patterns. This implies that the same major REE-bearing phase is common to all the samples. The postleach residues contain REE in other phases. The acid-soluble phases associated with separated minerals from 75055 are depleted in REE relative to P, and also relative to REE and P in the bulk igneous rock. This may be interpreted as partitioning of REE present at grain surfaces into the major minerals.

  20. Rare earth and trace element geochemistry of a fragment of Jurassic seafloor, Point Sal, California

    NASA Technical Reports Server (NTRS)

    Menzies, M.; Blanchard, D.; Brannon, J.; Korotev, R.

    1977-01-01

    Rocks from an ophiolite suite once on the seafloor were analyzed for rare earth elements (REE), Sc, Co, Na2O, Cr, Zn and FeO. Strontium isotope exchange noted in some of the lavas is attributed to basalt-seawater interaction; the Ce abundance in smectite- and zeolite-bearing lavas may also be due to prolonged exposure to seawater. The higher grades of metamorphic rock, however, show no variation from the usual flat or slightly light REE depleted profiles. Plutonic igneous rock, all light REE depleted, have total REE abundances varying by a factor of 100 between the dunites and diorites. In order of decreasing REE abundance are hornblende, clinopyroxene, plagioclase, orthopyroxene and olivine. Calculations of REE contents of liquids in equilibrium with early cumulative clinopyroxenes suggest that the parent to the stratiform sequence was more depleted in light REE than the parent to the lava pile.

  1. Role of ligands in accumulation and fractionation of rare Earth elements in plants: examples of phosphate and citrate.

    PubMed

    Ding, Shiming; Liang, Tao; Zhang, Chaosheng; Yan, Juncai; Zhang, Zili; Sun, Qin

    2005-10-01

    Few studies have been carried out on the effects of ligands on rare earth element (REE) bioaccumulation processes. In this study, the effects of phosphate (Pi, an inorganic ligand) and citrate (an organic ligand) on accumulation and fractionation of REEs in wheat were investigated using aqueous culture with extraneous mixed REEs (MRE). The results show that initial Pi solution culture at various levels followed by exposure to a fixed-MRE solution did not significantly change the total concentrations of REEs (SigmaREE) in roots, whereas the SigmaREE in leaves dramatically decreased with increasing levels of Pi applied. Simultaneous culture of wheat with mixture of MRE and citrate solutions caused obvious decreases of the SigmaREE in both roots and leaves. Compared with MRE, significant fractionations of REEs were found in wheat organs when no ligand was applied. Notable middle REE (MREE) enrichment and M-type tetrad effect were observed in the roots, and heavy REE (HREE) enrichment and W-type tetrad effect existed in the leaves. Pi treatments did not significantly affect the fractionations of REEs in the roots, but enrichment of HREEs in the leaves slightly increased at the highest level of Pi applied. Fractionations of REEs in both roots and leaves decreased with increasing levels of citrate applied; at higher levels of citrate (> or =150 microM), no above fractionation features were observed in wheat, but light REE (LREE) enrichment existed in the roots and leaves. The results indicate that ligands might play important roles in accumulation and fractionation of REEs during bioaccumulation processes.

  2. Geochemistry of rare earth elements in Permian coals from the Huaibei Coalfield, China

    USGS Publications Warehouse

    Zheng, Lingyun; Liu, Gaisheng; Chou, C.-L.; Qi, C.; Zhang, Y.

    2007-01-01

    The rare earth elements (REEs) in coals are important because of: (a) REE patterns can be an indicator of the nature of source rocks of the mineral matter as well as sedimentary environments; (b) REEs abundance in coal may have industrial-significance. In this study, a total of thirty-four samples of Permian coal, partings, roof, and floor were collected from the Huaibei Coalfield, Anhui Province, China. Abundances of rare earth elements (REEs) and other elements in the samples were determined by inductively coupled-plasma mass spectrometry (ICP-MS) and inductively coupled-plasma atomic emission spectrometry (ICP-AES). The results show that the REEs are enriched in coals in the Huaibei Coalfield as compared with Chinese and U.S. coals and the world coal average. Coals in the Lower Shihezi Formation (No. 7, 5, and 4 Coals) and Upper Shihezi Formation (No. 3) have higher REE abundances than the coals in Shanxi Formation (No. 10). Magmatic intrusion resulted in high enrichment of REEs concentrations in No. 5 and 7 Coals. The REE abundances are positively correlated with the ash content. The mineral matter in these coals is mainly made up of clay minerals and carbonates. The REEs are positively correlated with lithophile elements including Si, Al, Ti, Fe, and Na, which are mainly distributed in clay minerals, indicating that REEs are contained mainly in clay minerals. The REE abundances in coals normalized by the ash are higher than that in partings. REEs abundances of coals cannot be accounted for by the REE content in the mineral matter, and some REEs associated with organic matter in coals. ?? 2007 Elsevier Ltd. All rights reserved.

  3. Geochemistry of rare earth elements in Permian coals from the Huaibei Coalfield, China

    NASA Astrophysics Data System (ADS)

    Zheng, Liugen; Liu, Guijian; Chou, Chen-Lin; Qi, Cuicui; Zhang, Ying

    2007-10-01

    The rare earth elements (REEs) in coals are important because of: (a) REE patterns can be an indicator of the nature of source rocks of the mineral matter as well as sedimentary environments; (b) REEs abundance in coal may have industrial-significance. In this study, a total of thirty-four samples of Permian coal, partings, roof, and floor were collected from the Huaibei Coalfield, Anhui Province, China. Abundances of rare earth elements (REEs) and other elements in the samples were determined by inductively coupled-plasma mass spectrometry (ICP-MS) and inductively coupled-plasma atomic emission spectrometry (ICP-AES). The results show that the REEs are enriched in coals in the Huaibei Coalfield as compared with Chinese and U.S. coals and the world coal average. Coals in the Lower Shihezi Formation (No. 7, 5, and 4 Coals) and Upper Shihezi Formation (No. 3) have higher REE abundances than the coals in Shanxi Formation (No. 10). Magmatic intrusion resulted in high enrichment of REEs concentrations in No. 5 and 7 Coals. The REE abundances are positively correlated with the ash content. The mineral matter in these coals is mainly made up of clay minerals and carbonates. The REEs are positively correlated with lithophile elements including Si, Al, Ti, Fe, and Na, which are mainly distributed in clay minerals, indicating that REEs are contained mainly in clay minerals. The REE abundances in coals normalized by the ash are higher than that in partings. REEs abundances of coals cannot be accounted for by the REE content in the mineral matter, and some REEs associated with organic matter in coals.

  4. Rare Earth Element Behavior During Incongruent Weathering and Varying Discharge Conditions in Silicate Dominated River Systems: The Australian Victorian Alps

    NASA Astrophysics Data System (ADS)

    Hagedorn, K. B.; Cartwright, I.

    2008-12-01

    The distribution of rare earth elements (REE) and trace elements was measured by ICP-MS on fresh, slightly weathered and weathered granite and surface water samples from a network of 11 pristine rivers draining the Australian Victorian Alps during (i) high and (ii) low discharge conditions. River water REE concentrations are largely derived from atmospheric precipitation (rain, snow), as indicated by similar Chondrite normalized REE patterns (higher LREE over HREE; negative Ce anomalies, positive Eu anomalies) and similar total REE concentrations during both dry and wet seasons. Calculations based on the covariance between REE and Cl concentrations and oxygen and hydrogen isotopes indicate precipitation input coupled with subsequent evaporation may account for 30% o 100% of dissolved REE in stream waters. The dissolved contribution to the granitic substratum to stream water comes mainly from the transformation of plagioclase to smectite, kaolinite and gibbsite and minor apatite dissolution. However, since most REE of the regional granite are present in accessory minerals (titanite, zircon, etc.) they do not significantly contribute to the river REE pool. REE concentrations drop sharply downstream as a result of dilution and chemical attenuation. A trend of downstream enrichment of the heavier REE is due to selective partitioning of the lighter REE (as both free REE or REECO3 complexes) to hydrous oxides of suspended Al which, in turn, is controlled by a downstream increase of pH to values > 6.1 (for free REE) and > 7.3 (for REECO3 complexes). Although most circumneutral waters were supersaturated with REE phosphate compounds, precipitation of LnPO4 is not believed to have been a dominant process because the predicted phosphate fractionation pattern is inconsistent with the observed trends. Negative saturation indices of hydrous ferric oxides also militate against surface complexation onto goethite. Instead, REE attenuation most likely resulted from adsorption onto

  5. Scarcity of rare earth elements.

    PubMed

    de Boer, M A; Lammertsma, K

    2013-11-01

    Rare earth elements (REEs) are important for green and a large variety of high-tech technologies and are, therefore, in high demand. As a result, supply with REEs is likely to be disrupted (the degree of depends on the REE) in the near future. The 17 REEs are divided into heavy and light REEs. Other critical elements besides REEs, identified by the European Commission, are also becoming less easily available. Although there is no deficiency in the earth's crust of rare earth oxides, the economic accessibility is limited. The increased demand for REEs, the decreasing export from China, and geopolitical concerns on availability contributed to the (re)opening of mines in Australia and the USA and other mines are slow to follow. As a result, short supply of particularly terbium, dysprosium, praseodymium, and neodymium is expected to be problematic for at least the short term, also because they cannot be substituted. Recycling REEs from electronic waste would be a solution, but so far there are hardly any established REE recycling methods. Decreasing the dependency on REEs, for example, by identifying possible replacements or increasing their efficient use, represents another possibility.

  6. Rare earths in the Leadville Limestone and its marble derivates

    USGS Publications Warehouse

    Jarvis, J.C.; Wildeman, T.R.; Banks, N.G.

    1975-01-01

    Samples of unaltered and metamorphosed Leadville Limestone (Mississippian, Colorado) were analyzed by neutron activation for ten rare-earth elements (REE). The total abundance of the REE in the least-altered limestone is 4-12 ppm, and their distribution patterns are believed to be dominated by the carbonate minerals. The abundances of the REE in the marbles and their sedimentary precursors are comparable, but the distribution patterns are not. Eu is enriched over the other REE in the marbles, and stratigraphically upward in the formation (samples located progressively further from the heat source), the light REE become less enriched relative to the heavy REE. The Eu anomaly is attributed to its ability, unique among the REE, to change from the 3+ to 2+ oxidation state. Whether this results in preferential mobilization of the other REE or whether this reflects the composition of the pore fluid during metamorphism is unknown. Stratigraphically selective depletion of the heavy REE may be attributed to more competition for the REE between fluid and carbonate minerals in the lower strata relative to the upper strata. This competition could have been caused by changes in the temperature of the pore fluid or to the greater resistance to solution of the dolomite in the lower parts of the formation than the calcite in the upper parts. ?? 1975.

  7. A Comparison of Predictive Equations of Energy Expenditure and Measured Energy Expenditure in Critically Ill Patients

    PubMed Central

    Kross, Erin K.; Sena, Matthew; Schmidt, Karyn; Stapleton, Renee D.

    2012-01-01

    PURPOSE Multiple equations exist for predicting resting energy expenditure (REE). The accuracy of these for estimating caloric requirements of critically ill patients is not clear, especially for obese patients. We sought to compare REE, calculated with published formulas, with measured REE in a cohort of mechanically-ventilated subjects. MATERIALS AND METHODS We retrospectively identified all mechanically-ventilated patients with measured body mass index (BMI) who underwent indirect calorimetry (IC) in the ICU. Limits of agreement and Pitman’s test of difference in variance were performed to compare REE by equations with REE measured by IC. RESULTS 927 patients were identified, including 401 obese patients. There was bias and poor agreement between measured REE and REE predicted by the Harris-Benedict, Owen, ACCP, and Mifflin equations (p > 0.05). There was poor agreement between measured and predicted REE by the Ireton-Jones equation, stratifying by gender. Ireton-Jones was the only equation which was unbiased, for men and those in weight categories I and II. In all cases except Ireton-Jones, predictive equations underestimated measured REE. CONCLUSION None of these equations accurately estimated measured REE in this group of mechanically-ventilated patients, most underestimating caloric needs. Development of improved predictive equations for adequate assessment of energy needs is needed. PMID:22425340

  8. Rare earth patterns in shergottite phosphates and residues

    NASA Technical Reports Server (NTRS)

    Laul, J. C.

    1987-01-01

    Leaching experiments with 1M HCl on ALHA 77005 powder show that rare earth elements (REE) are concentrated in accessory phosphate phases (whitlockite, apatite) that govern the REE patterns of bulk shergottites. The REE patterns of whitlockite are typically light REE-depleted with a negative Eu anomaly and show a hump at the heavy REE side, while the REE pattern of apatite (in Shergotty) is light REE-enriched. Parent magmas are calculated from the modal compositions of residues of ALHA 77005, Shergotty, and EETA 79001. The parent magmas lack a Eu anomaly, indicating that plagioclase was a late-stage crystallizing phase and that it probably crystallized before the phosphates. The parent magmas of ALHA 77005 and Shergotty have similar REE patterns, with a subchondritic Nd/Sm ratio. However, the Sm/Nd isotopoics require a light REE-depleted source for ALHA 77005 (if the crystallization age is less than 600 Myr) and a light REE-enriched source for Shergotty. Distant Nd and Sr isotopic signatures may suggest different source regions for shergottites.

  9. Effects of spraying rare earths on contents of rare Earth elements and effective components in tea.

    PubMed

    Wang, Dongfeng; Wang, Changhong; Ye, Sheng; Qi, Hongtao; Zhao, Guiwen

    2003-11-05

    Rare earth (RE) fertilizer is widely applied in China to increase the yield and the quality of crops including tea. However, the effects of spraying RE fertilizer on the contents of rare earth elements (REE) and effective components in tea are unknown. The results from basin and field experiments show that the values of the REE concentrations in new shoots of tea plants and the concentration of REE in the soil (REE/REEs) either from control basins or from treatment basins were smaller than those in other parts of tea plant and similar between control and treatment. The longer the interval between spraying RE fertilizer and picking the shoots of tea plants, the less the effects from spraying. About 80% summation operator REE (the sum of the concentrations of 15 REE) in tea, whether it came from spraying or not, was insoluble in the infusion. About 10% the soluble REE of summation operator REE in tea infusion was bound to polysaccharide, and the amount of REE bound polysaccharide decreased over time. At least a 25 day safety interval is needed between spraying and picking if the microelement fertilizer is used, in order to enhance tea output and to ensure tea safety.

  10. Steric hindrance and the enhanced stability of light rare-earth elements in hydrothermal fluids

    USGS Publications Warehouse

    Mayanovic, Robert A.; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

    2009-01-01

    A series of X-ray absorption spectroscopy (XAS) experiments were made to determine the structure and stability of aqueous REE (La, Nd, Gd, and Yb) chloride complexes to 500 ??C and 520 MPa. The REE3+ ions exhibit inner-sphere chloroaqua complexation with a steady increase of chloride coordination with increasing temperature in the 150 to 500 ??C range. Furthermore, the degree of chloride coordination of REE3+ inner-sphere chloroaqua complexes decreases significantly from light to heavy REE. These results indicate that steric hindrance drives the reduction of chloride coordination of REE3+ inner-sphere chloroaqua complexes from light to heavy REE. This results in greater stability and preferential transport of light REE3+ over heavy REE3+ ions in saline hydrothermal fluids. Accordingly, the preferential mobility of light REE directly influences the relative abundance of REE in rocks and minerals and thus needs to be considered in geochemical modeling of petrogenetic and ore-forming processes affected by chloride-bearing hydrothermal fluids.

  11. The behavior of rare earth elements in naturally and anthropogenically acidified waters

    USGS Publications Warehouse

    Wood, Scott A.; Gammons, Christopher H.; Parker, Stephen R.

    2006-01-01

    In this paper, the behavior of rare earth elements (REE) in a watershed impacted by acid-mine drainage (Fisher Creek, Montana) is compared to that in a volcanically acidified watershed (Rio Agrio and Lake Caviahue, Argentina). The REE behave conservatively in acidic waters with pH values less than approximately 5.5. However, above pH 5.5, REE concentrations are controlled by adsorption onto or co-precipitation with a variety of Fe or Al oxyhydroxides. The heavy REE partition to a greater extent into the solid phase than the light REE as pH rises above 6. Concentrations of REE exhibit diel (24-h) cycling in waters that were initially acidic, but have become neutralized downstream. In Fisher Creek, at the most downstream sampling station investigated (pH 6.8), concentrations of dissolved REE were 190–840% higher in the early morning versus the late afternoon. This cycling can be related to temperature-dependent, cyclic adsorption–desorption of REE onto hydrous ferric or aluminum oxide or both. Similar but gentler diel cycling of the REE was found at Rio Agrio. The existence of such cycling has important ramifications for the study of REE in natural waters.

  12. Rare earth element migration in gullies with different Dicranopteris dichotoma covers in the Huangnikeng gully group, Changting County, Southeast China.

    PubMed

    Chen, Zhiqiang; Chen, Zhibiao; Bai, Liyue

    2016-12-01

    Little is known about rare earth element (REE) migration in gullies in Southeast China. We examine the concentration and distribution of REE, soil variables, and correlations among REE and soil variables field investigation, laboratory measurement, and statistical analysis in the three gullies with different Dicranopteris dichotoma covers in the Huangnikeng gully group, Changting County, Southeast China. We show that the REE pattern in gullies is typical of red soil in Southeast China. REE migrate severely in gullies with low vegetation cover, REE migrate from higher sites to lower sites under the influence of water flow and gravity, and gullies can be considered an important REE source. Dicranopteris dichotoma can succeed in gullies and affect part of soil variables, organic C and pH can play an important role in REE migration in gullies, and Dicranopteris dichotoma is a recommended plant for effectively controlling REE migration and gully erosion. The critical vegetation cover of gullies should be further studied to control REE migration and gully erosion.

  13. The effect of diagenesis and fluid migration on rare earth element distribution in pore fluids of the northern Cascadia accretionary margin

    USGS Publications Warehouse

    Kim, Ji-Hoon; Torres, Marta E.; Haley, Brian A.; Kastner, Miriam; Pohlman, John W.; Riedel, Michael; Lee, Young-Joo

    2012-01-01

    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.

  14. Effect of low doses of dietary rare earth elements on growth performance of broilers.

    PubMed

    He, M L; Wehr, U; Rambeck, W A

    2010-02-01

    The present study was designed to investigate effect of dietary rare earth elements (REE), including both organic and inorganic compounds, on growth performance of broilers. In experiment 1, a total of 180 male Ross broiler chicks were allocated to 72 pens with different assignment: four chicks per pen or individually. The following three treatment diets were applied: control, REE-chlorides at a dose of 40 mg/kg and REE-citrate at a dose of 70 mg/kg. Each treatment group had 24 pens containing both assignments (12 pens each). In experiment 2, a total of 72 male 3-day-old Ross broiler chicks were separated to four groups: control, REE-chlorides at a dose of 70 mg/kg and REE-citrate at doses of 70 mg/kg and 100 mg/kg. In experiment 1, dietary REE-citrate improved body weight gain during the overall period by 5.0% (p < 0.05) while the increase with REE-chloride was not significant. In experiment 2, growth effects (p < 0.05) were only found in the period from day 21 to slaughter with all REE forms, and feed conversion ratio was improved by 3.4% (p < 0.05) with REE-citrate. No significant effects of REE were found on chill weight, percentages of breast meat, thigh weight, drumstick weight and wing weight. Concentrations of La and Ce in the liver and muscles were very low, accounting for 0.11-0.76 and 0.02-0.30 mg/kg respectively. There was weak tendency for a dose-response relationship especially in the groups supplemented with REE-chlorides. The main blood serum biochemical parameters were not significantly affected by REE in the diets. The results suggest that dietary supplementation of low doses of REE-citrates might improve growth performance of broilers without affecting carcass composition and health of the broilers.

  15. LA-ICP-MS of rare earth elements concentrated in cation-exchange resin particles for origin attribution of uranium ore concentrate.

    PubMed

    Asai, Shiho; Limbeck, Andreas

    2015-04-01

    Rare earth elements (REE) concentrated on cation-exchange resin particles were measured with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to obtain chondrite-normalized REE plots. The sensitivity of REE increased in ascending order of the atomic number, according to the sensitivity trend in pneumatic nebulization ICP-MS (PN-ICP-MS). The signal intensities of REE were nearly proportional to the concentrations of REE in the immersion solution used for particle-preparation. Minimum measurable concentration calculated from the net signals of REE was approximately 1 ng/g corresponding to 0.1 ng in the particle-preparation solution. In LA analysis, formation of oxide and hydroxide of the light REE and Ba which causes spectral interferences in the heavy REE measurement was effectively attenuated due to the solvent-free measurement capability, compared to conventional PN-ICP-MS. To evaluate the applicability of the proposed method, the REE-adsorbed particles prepared by immersing them in a U-bearing solution (commercially available U standard solution) were measured with LA-ICP-MS. Aside from the LA analysis, each concentration of REE in the same U standard solution was determined with conventional PN-ICP-MS after separating REE by cation-exchange chromatography. The concentrations of REE were ranging from 0.04 (Pr) to 1.08 (Dy) μg/g-U. The chondrite-normalized plot obtained through LA-ICP-MS analysis of the U standard sample exhibited close agreement with that obtained through the PN-ICP-MS of the REE-separated solution within the uncertainties.

  16. Trends in the Rare Earth Element Content of U.S.-Based Coal Combustion Fly Ashes.

    PubMed

    Taggart, Ross K; Hower, James C; Dwyer, Gary S; Hsu-Kim, Heileen

    2016-06-07

    Rare earth elements (REEs) are critical and strategic materials in the defense, energy, electronics, and automotive industries. The reclamation of REEs from coal combustion fly ash has been proposed as a way to supplement REE mining. However, the typical REE contents in coal fly ash, particularly in the United States, have not been comprehensively documented or compared among the major types of coal feedstocks that determine fly ash composition. The objective of this study was to characterize a broad selection of U.S. fly ashes of varied geological origin in order to rank their potential for REE recovery. The total and nitric acid-extractable REE content for more than 100 ash samples were correlated with characteristics such as the major element content and coal basin to elucidate trends in REE enrichment. Average total REE content (defined as the sum of the lanthanides, yttrium, and scandium) for ashes derived from Appalachian sources was 591 mg kg(-1) and significantly greater than in ashes from Illinois and Powder River basin coals (403 and 337 mg kg(-1), respectively). The fraction of critical REEs (Nd, Eu, Tb, Dy, Y, and Er) in the fly ashes was 34-38% of the total and considerably higher than in conventional ores (typically less than 15%). Powder River Basin ashes had the highest extractable REE content, with 70% of the total REE recovered by heated nitric acid digestion. This is likely due to the higher calcium content of Powder River Basin ashes, which enhances their solubility in nitric acid. Sc, Nd, and Dy were the major contributors to the total REE value in fly ash, based on their contents and recent market prices. Overall, this study shows that coal fly ash production could provide a substantial domestic supply of REEs, but the feasibility of recovery depends on the development of extraction technologies that could be tailored to the major mineral content and origins of the feed coal for the ash.

  17. An Experimental Study on Using Rare Earth Elements to Trace Non-point source Phosphorous LossA

    NASA Astrophysics Data System (ADS)

    Liang, T.

    2011-12-01

    Controlling phosphorous (P) inputs through management of its sources and transport is critical for limiting freshwater eutrophication. Rare earth elements (REEs) have been successfully used in the analysis of soil erosion and pollutant sources, as well as in the analysis of mineral genesis. To better understand the potential for REE use in tracing non-point sources of P, we examined the combined fate of REEs and P in Chinese soils amended with REEs and documented the formation of REE-P compounds. Laboratory leaching experiments and artificial simulated rainfall experiments were conducted. Vertical leaching transfers of REEs and P were relatively small, with transport depths less than 6 cm for most REEs and P. Export of applied REEs in leachate accounted for less that 5% of inputs. The vertical mobility order of REEs and P in Chinese soils was greatest for purple soil, followed by terra nera soil, then red soil, followed by cinnamon soil, and finally loess soil. Losses of rare earth elements and P in surface runoff exhibited a parabolic relationship to simulated rainfall intensity. With greater exogenous La application, the amount of water soluble P, bicarbonate-extractable P and hydroxide-extractable P decreased significantly, while acid-extractable and residual forms of P increased significantly. In addition, characteristics of exogenous rare earth elements (REEs) and P and their losses with surface runoff (both in the water and sediments) during simulated rainfall experiments (83 mm h-1) were investigated. The results revealed that most REEs (La, 94%; Nd, 93%; Sm, 96%) and P (96%) transported with sediments in the runoff. The total amounts of losses of REEs and P in the runoff were significantly correlated, suggesting the possibility of using REEs to trace the fate of agricultural nonpoint P losses.

  18. Rare Earth Element Partitioning in Lunar Minerals: An Experimental Study

    NASA Technical Reports Server (NTRS)

    McIntosh, E. C.; Rapp, J. F.; Draper, D. S.

    2016-01-01

    The partitioning behavior of rare earth elements (REE) between minerals and melts is widely used to interpret the petrogenesis and geologic context of terrestrial and extra-terrestrial samples. REE are important tools for modelling the evolution of the lunar interior. The ubiquitous negative Eu anomaly in lunar basalts is one of the main lines of evidence to support the lunar magma ocean (LMO) hypothesis, by which the plagioclase-rich lunar highlands were formed as a flotation crust during differentiation of a global-scale magma ocean. The separation of plagioclase from the mafic cumulates is thought to be the source of the Eu depletion, as Eu is very compatible in plagioclase. Lunar basalts and volcanic glasses are commonly depleted in light REEs (LREE), and more enriched in heavy REEs (HREE). However, there is very little experimental data available on REE partitioning between lunar minerals and melts. In order to interpret the source of these distinctive REE patterns, and to model lunar petrogenetic processes, REE partition coefficients (D) between lunar minerals and melts are needed at conditions relevant to lunar processes. New data on D(sub REE) for plagioclase, and pyroxenes are now available, but there is limited available data for olivine/melt D(sub REE), particularly at pressures higher than 1 bar, and in Fe-rich and reduced compositions - all conditions relevant to the lunar mantle. Based on terrestrial data, REE are highly incompatible in olivine (i.e. D much less than 1), however olivine is the predominant mineral in the lunar interior, so it is important to understand whether it is capable of storing even small amounts of REE, and how the REEs might be fractionatied, in order to understand the trace element budget of the lunar interior. This abstract presents results from high-pressure and temperature experiments investigating REE partitioning between olivine and melt in a composition relevant to lunar magmatism.

  19. Modelling of Rare Earth Elements Complexation With Humic Acid

    NASA Astrophysics Data System (ADS)

    Pourret, O.; Davranche, M.; Gruau, G.; Dia, A.

    2006-12-01

    The binding of rare earth elements (REE) to humic acid (HA) was studied by combining Ultrafiltration and ICP- MS techniques. REE-HA complexation experiments were performed at various pH conditions (ranging from 2 to 10.5) using a standard batch equilibration method. Results show that the amount of REE bound to HA strongly increase with increasing pH. Moreover, a Middle REE (MREE) downward concavity is evidenced by REE distribution patterns at acidic pH. Modelling of the experimental data using Humic Ion Binding Model VI provided a set of log KMA values (i.e. the REE-HA complexation constants specific to Model VI) for the entire REE series. The log KMA pattern obtained displays a MREE downward concavity. Log KMA values range from 2.42 to 2.79. These binding constants are in good agreement with the few existing datasets quantifying the binding of REE with humic substances except a recently published study which evidence a lanthanide contraction effect (i.e. continuous increase of the constant from La to Lu). The MREE downward concavity displayed by REE-HA complexation pattern determined in this study compares well with results from REE-fulvic acid (FA) and REE-acetic acid complexation studies. This similarity in the REE complexation pattern shapes suggests that carboxylic groups are the main binding sites of REE in HA. This conclusion is further supported by a detailed review of published studies for natural, organic-rich, river- and ground-waters which show no evidence of a lanthanide contraction effect in REE pattern shape. Finally, application of Model VI using the new, experimentally determined log KMA values to World Average River Water confirms earlier suggestions that REE occur predominantly as organic complexes (> 60 %) in the pH range between 5-5.5 and 7-8.5 (i.e. in circumneutral pH waters). The only significant difference as compared to earlier model predictions made using estimated log KMA values is that the experimentally determined log KMA values

  20. Rare earth and trace elements of fossil vertebrate bioapatite as palaeoenvironmental and sedimentological proxies

    NASA Astrophysics Data System (ADS)

    Žigaitė, Živilė; Fadel, Alexandre; Pérez-Huerta, Alberto; Jeffries, Teresa

    2015-04-01

    Rare earth (REE) and trace element compositions of fossil vertebrate dental microremains have been studied in Silurian and Devonian vertebrate dental scales and spines in-situ, using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Samples were selected from the well-known Silurian bone beds of Vesiku and Ohesaare in Saaremaa island of Estonia, and a number of Lower Devonian localities from Spitsbergen (Svalbard), Andrée Land group. Biomineral preservation was assessed using spot semi-quantitative elemental chemistry (SEM-EDS) and electron back-scatter difractometry (EBSD) for cristallinity imaging. The obtained PAAS shale-normalised REE concentrations were evaluated using basic geochemical calculations and quantifications. The REE patterns from the Lower Devonian vertebrate apatite from Andrée Land, Spitsbergen (Wood Bay and Grey Hœk formations) did not show any recognisable taxon-specific behavior, but had rather well expressed differences of REE compositions related to biomineral structure and sedimentary settings, suggesting REE instead to reflect burial environments and sedimentological history. The Eu anomaly recorded in two of the studied localities but not in the other indicate different taphonomic conditions and palaeoenvironment, while La/Sm, La/Yb ratios sugeest considerable influence of terrestrial freshwater during the early diagenesis. The La/Yb and La/Sm plots also agree with the average REE concentrations, reflecting domination of the adsoption over substitution as principal REE uptake mechanism in the fossils which had significantly lower overall REE concentrations, and vice versa. Vesiku (Homerian, Wenlock) microremains yielded very uniform REE patterns with slightly lower overall REE concentrations in enameloid than in dentine, with strong enrichment in middle REE and depletion in heavy REE. Negative Europium (Eu) anomaly was pronounced in all the profiles, but Cerium (Ce) anomalies were not detected suggesting possible

  1. Rare earth elements in river waters

    NASA Technical Reports Server (NTRS)

    Goldstein, Steven J.; Jacobsen, Stein B.

    1988-01-01

    To characterize the input to the oceans of rare earth elements (REE) in the dissolved and the suspended loads of rivers, the REE concentrations were measured in samples of Amazon, Indus, Mississippi, Murray-Darling, and Ohio rivers and in samples of smaller rivers that had more distinct drainage basin lithology and water chemistry. It was found that, in the suspended loads of small rivers, the REE pattern was dependent on drainage basin geology, whereas the suspended loads in major rivers had relatively uniform REE patterns and were heavy-REE depleted relative to the North American Shale composite (NASC). The dissolved loads in the five major rivers had marked relative heavy-REE enrichments, relative to the NASC and the suspended material, with the (La/Yb)N ratio of about 0.4 (as compared with the ratio of about 1.9 in suspended loads).

  2. Fingerprinting of ground water by ICP-MS. Progress report, April 1, 1994--June 30, 1994

    SciTech Connect

    Stetzenbach, K.

    1994-09-01

    Rare earth element (REE) concentrations were measured in groundwater from Ash Meadows, Nevada and Death Valley National Monument, Nevada and California. The shale-normalized REE profiles for groundwaters from Ash Meadows are similar to those of the Furnace Creek region in Death Valley. These similar patterns support previous suggestions that the groundwater discharging in Ash Meadows is related to that emerging at Furnace Creek. Speciation modelling Indicates that 77% to greater than 99% of each REE is complexed with carbonate ions in these waters and that carbonate species (i.e., LnCO{sub 3}{sup +}) dominate for the light REEs and dicarbonato species (i.e., LnCO{sub 3}){sub 2}{sup {minus}} are more important for the HREEs. Calculated activity products for solid REE phosphate coprecipitates indicate that these groundwaters are all approximately saturated with respect to these phases indicating that these phases may limit the dissolved REE concentrations.

  3. Magnesian anorthosites and associated troctolites and dunite in Apollo 14 breccias

    SciTech Connect

    Lindstrom, M.M.; Knapp, S.A.

    1984-11-15

    Magnesian anorthosite, a new type of pristine lunar highlands rock, has been found in Apollo 14 breccias. It has primitive (high Ca and Mg) silicate mineral compositions, and high and variable REE concentrations. Variations in REE contents can be accounted for by variations in modal abundance of REE-rich apatite. Magnesian anorthosites are associated with troctolites and a dunite with very similar mineral compositions and it is suggested that all crystallized from a differentiated troctolitic intrusion. The origin of the REE-rich apatite is enigmatic. It is unlikely to have crystallized from an igneous liquid in equilibrium with the major minerals in the anorthosite. Possible origins are assimilation of urKREEP or metasomatism by REE-rich fluids. REE-rich alkali anorthosites and gabbronorites are also found and are likely to be related to KREEP basalt magmas. Lunar compositional associations are distributed in a regional rather than global manner.

  4. Magnesian anorthosites and associated troctolites and dunite in Apollo 14 breccias

    NASA Technical Reports Server (NTRS)

    Lindstrom, M. M.; Knapp, S. A.; Shervais, J. W.; Taylor, L. A.

    1984-01-01

    Magnesian anorthosite, a new type of pristine lunar highlands rock, has been found in Apollo 14 breccias. It has primitive (high Ca and Mg) silicate mineral compositions, and high and variable REE concentrations. Variations in REE contents can be accounted for by variations in modal abundance of REE-rich apatite. Magnesian anorthosites are associated with troctolites and a dunite with very similar mineral compositions and it is suggested that all crystallized from a differentiated troctolitic intrusion. The origin of the REE-rich apatite is enigmatic. It is unlikely to have crystallized from an igneous liquid in equilibrium with the major minerals in the anorthosite. Possible origins are assimilation of urKREEP or metasomatism by REE-rich fluids. REE-rich alkali anorthosites and gabbronorites are also found and are likely to be related to KREEP basalt magmas. Lunar compositional associations are distributed in a regional rather than global manner.

  5. Rare earth elements minimal harvest year variation facilitates robust geographical origin discrimination: The case of PDO "Fava Santorinis".

    PubMed

    Drivelos, Spiros A; Danezis, Georgios P; Haroutounian, Serkos A; Georgiou, Constantinos A

    2016-12-15

    This study examines the trace and rare earth elemental (REE) fingerprint variations of PDO (Protected Designation of Origin) "Fava Santorinis" over three consecutive harvesting years (2011-2013). Classification of samples in harvesting years was studied by performing discriminant analysis (DA), k nearest neighbours (κ-NN), partial least squares (PLS) analysis and probabilistic neural networks (PNN) using rare earth elements and trace metals determined using ICP-MS. DA performed better than κ-NN, producing 100% discrimination using trace elements and 79% using REEs. PLS was found to be superior to PNN, achieving 99% and 90% classification for trace and REEs, respectively, while PNN achieved 96% and 71% classification for trace and REEs, respectively. The information obtained using REEs did not enhance classification, indicating that REEs vary minimally per harvesting year, providing robust geographical origin discrimination. The results show that seasonal patterns can occur in the elemental composition of "Fava Santorinis", probably reflecting seasonality of climate.

  6. Rare earth elements in intertidal sediments of Bohai Bay, China: concentration, fractionation and the influence of sediment texture.

    PubMed

    Zhang, Yong; Gao, Xuelu; Arthur Chen, Chen-Tung

    2014-07-01

    Surface sediments from intertidal Bohai Bay were assessed using a four-step sequential extraction procedure to determine their concentrations of rare earth elements (REEs) and the chemical forms in which those elements were present. The normalized ratios La/Gd and La/Yb showed that LREE contents were not significantly higher than the middle REEs or HREE contents. A negative Ce anomaly and positive Eu were observed in sand and silty sand sediments, whereas no significant Ce or Eu anomaly was found in clayey silt sediments. Residual fraction of REEs accounted for the majority of their total concentrations. Middle REEs were more easily leached than other REEs, especially in clayey silt sediment. REEs contents in the surface sediment from the intertidal Bohai Sea were consistent with data from the upper continental crust and China shallow sea sediments, indicating that they were generally unaffected by heavily anthropogenic effects from adjacent areas.

  7. Mesosiderite clasts with the most extreme positive europium anomalies among solar system rocks

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.; Rubin, Alan E.; Davis, Andrew M.

    1992-01-01

    Pigeonite-plagioclase gabbros that occur as clasts in mesosiderites (brecciated stony-iron meteorites) show extreme fractionations of the rare-earth elements (REEs) with larger positive europium anomalies than any previously known for igneous rocks from the earth, moon, or meteorite parent bodies and greater depletions of light REEs relative to heavy REEs than known for comparable cumulate gabbros. The REE pattern for merrillite in one of these clasts is depleted in light REEs and has a large positive europium anomaly as a result of metamorphic equilibration with the silicates. The extreme REE ratios exhibited by the mesosiderite clasts demonstrate that multistage igneous processes must have occurred on some asteroids in the early solar system. Melting of the crust by large-scale impacts or electrical induction from an early T-Tauri-phase sun may be responsible for these processes.

  8. Global demand for rare earth resources and strategies for green mining.

    PubMed

    Dutta, Tanushree; Kim, Ki-Hyun; Uchimiya, Minori; Kwon, Eilhann E; Jeon, Byong-Hun; Deep, Akash; Yun, Seong-Taek

    2016-10-01

    Rare earth elements (REEs) are essential raw materials for emerging renewable energy resources and 'smart' electronic devices. Global REE demand is slated to grow at an annual rate of 5% by 2020. This high growth rate will require a steady supply base of REEs in the long run. At present, China is responsible for 85% of global rare earth oxide (REO) production. To overcome this monopolistic supply situation, new strategies and investments are necessary to satisfy domestic supply demands. Concurrently, environmental, economic, and social problems arising from REE mining must be addressed. There is an urgent need to develop efficient REE recycling techniques from end-of-life products, technologies to minimize the amount of REEs required per unit device, and methods to recover them from fly ash or fossil fuel-burning wastes.

  9. Metasomatism in a subduction complex: Constraints from microanalysis of trace elements in minerals from garnet amphibolite from the Catalina Schist

    SciTech Connect

    Hickmott, D.D.; Rogers, P.S.Z. ); Sorensen, S.S. )

    1992-04-01

    Trace element abundances and zoning were measured in minerals from a metasomatized garnet-amphibolite block from the Catalina Schist, using both ion and proton microprobes. Zoisite strongly concentrates light rare earth elements (REEs), Sr, Y, and Pb; amphibole concentrates Ni and Zn; garnet concentrates Y and heavy REEs; and titanite concentrates Nb. Major and trace elements in the garnets are zoned. Garnets in the core of the block display an overgrowth enriched in Mn, Y, and heavy REE, on a Y- and heavy-REE-pore core. Zirconium values remain relatively constant. The element enrichments in the garnet overgrowth suggest mobility of REEs at either a hand-sample or regional scale at subduction-zone pressure-temperature conditions. Metamorphic fluids may selectively transport heavy REEs relative to some high field strength elements in some convergent-margin settings. The distribution of Sr and Pb within subduction zones may reflect the dehydration and melting behavior of epidote-group minerals.

  10. Compositional and phase relations among rare earth element minerals

    NASA Technical Reports Server (NTRS)

    Burt, D. M.

    1990-01-01

    This paper discusses the compositional and phase relationships among minerals in which rare earth elements (REE) occur as essential constituents (e.g., bastnaesite, monazite, xenotime, aeschynite, allanite). Particular consideration is given to the vector representation of complex coupled substitutions in selected REE-bearing minerals and to the REE partitioning between minerals as related to the acid-base tendencies and mineral stabilities. It is shown that the treatment of coupled substitutions as vector quantities facilitates graphical representation of mineral composition spaces.

  11. Reassessing the Formation of CK7 Northwest Africa (NWA) 8186

    NASA Technical Reports Server (NTRS)

    Srinivasan, P.; McCubbin, F. M.; Lapen, T. J.; Righter, M.; Agee, C. B.

    2017-01-01

    The classification of meteorites is commonly determined using isotopes, modal mineralogy, and bulk compositions [1]. Bulk rare earth elements (REEs) in meteorites are additionally utilized to understand parent body processes. Numerous authors have shown that chondritic groups exhibit REE patterns that may be attributable to their parent bodies [e.g. 2-4], and variations in abundances and concentrations of REEs may reflect early nebular processes, thermal metamorphism, and aqueous alteration on the parent body [5-6].

  12. Distribution characteristics of rare earth elements in children's scalp hair from a rare earths mining area in southern China.

    PubMed

    Tong, Shi-Lu; Zhu, Wang-Zhao; Gao, Zhao-Hua; Meng, Yu-Xiu; Peng, Rui-Ling; Lu, Guo-Cheng

    2004-01-01

    In order to demonstrate the validity of using scalp hair rare earth elements (REEs) content as a biomarker of human REEs exposure, data were collected on REEs exposure levels from children aged 11-15 years old and living in an ion-adsorptive type light REEs (LREEs) mining and surrounding areas in southern China. Sixty scalp hair samples were analyzed by ICP-MS for 16 REEs (La Lu, Y and Sc). Sixteen REEs contents in the samples from the mining area (e.g., range: La: 0.14-6.93 microg/g; Nd: 0.09-5.27 microg/g; Gd: 12.2-645.6ng/g; Lu: 0.2-13.3 ng/g; Y: 0.03-1.27 microg/g; Sc: 0.05-0.30 microg/g) were significantly higher than those from the reference area (range: La: 0.04-0.40 microg/g; Nd: 0.04-0.32 microg/g; Gd: 8.3-64.6 ng/g; Lu: 0.4-3.3ng/g; Y: 0.03-0.29 microg/g; Sc: 0.11-0.36 microg/g) and even much higher than those published in the literature. The distribution pattern of REEs in scalp hair from the mining area was very similar to that of REEs in the mine and the atmosphere shrouding that area. In conclusion, the scalp hair REEs contents may indicate not only quantitatively but also qualitatively (distribution pattern) the absorption of REEs from environmental exposure into human body. The children living in this mining area should be regarded as a high-risk group with REEs (especially LREEs) exposure, and their health status should be examined from a REEs health risk assessment perspective.

  13. Rare earth element geochemistry of acid-sulphate and acid-sulphate-chloride geothermal systems from Yellowstone National Park, Wyoming, USA

    SciTech Connect

    Lewis, A.J.; Palmer, M.R.; Kemp, A.J.; Sturchio, N.C.

    1997-02-01

    Rare earth element (REE) concentrations have been determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) in acid-sulphate and acid-sulphate-chloride waters and the associated sinters and volcanic rocks from the Yellowstone National Park (YNP), Wyoming, USA, geothermal system. REE concentrations in the volcanic rocks range from 222 to 347 ppm: their chondrite-normalised REE patterns are typical of upper continental crust, with LREE > HREE and negative Eu anomalies. Total REE concentrations in the fluids range from 3 to 1133 nmol kg{sup -1} ({ge}162 ppm), and {Sigma}REE concentrations in sinter are {ge}181 ppm. REE abundances and patterns in drill core material from YNP indicate some REE mobility. Relative to the host rocks the REE patterns of the fluids are variably depleted in HREEs and LREEs, and usually have a pronounced positive Eu anomaly. This decoupling of Eu from the REE suite suggests that (1) Eu has been preferentially removed either from the host rock glass or from the host rock minerals, or (2) the waters are from a high temperature or reducing environment where Eu{sup 2+} is more soluble than the trivalent REEs. Since the latter is inconsistent with production of acid-sulphate springs in a low temperature, oxidising near-surface environment, we suggest that the positive Eu anomalies in the fluids result from preferential dissolution of a Eu-rich phase in the host rock. Spatial and temporal variations in major element chemistry and pH of the springs sampled from Norris Geyser Basin and Crater Hills accompany variations in REE concentrations and patterns of individual geothermal springs. These are possibly related to changes in subsurface plumbing, which results in variations in mixing and dilution of the geothermal fluids and may have lead to changes in the extent and nature of REE complexing. 37 refs., 7 figs., 4 tabs.

  14. Leaching of rare earth elements from fluorescent powder using the tea fungus Kombucha.

    PubMed

    Hopfe, Stefanie; Flemming, Katrin; Lehmann, Falk; Möckel, Robert; Kutschke, Sabine; Pollmann, Katrin

    2017-02-17

    In most modern technologies such as flat screens, highly effective magnets and lasers, as well as luminescence phosphors, Rare Earth Elements (REE) are used. Unfortunately no environmentally friendly recycling process exists so far. In comparison to other elements the interaction of microorganisms with REE has been studied to a less extent. However, as REE are ubiquitously present in nature it can be assumed that microorganisms play an important role in the biogeochemistry of REE. This study investigates the potential of organic acid-producing microbes for extracting REE from industrial waste. In Germany, 175 tons of fluorescent phosphor (FP) are collected per year as a distinct fraction from the recycling of compact fluorescent lamps. Because the FP contains about 10% of REE-oxides bound in the so-called triband dyes it is a readily accessible secondary resource of REE. Using the symbiotic mixed culture Kombucha, consisting of yeasts and acetic acid bacteria, REE were leached at a significant rate. The highest leaching-rates were observed in shake cultures using the entire Kombucha-consortium or its supernatant as leaching agent compared to experiments using the isolates Zygosaccharomyces lentus and Komagataeibacter hansenii as leaching organisms. During the cultivation, the pH decreased as a result of organic acid production (mainly acetic and gluconic acid). Thus, the underlying mechanism of the triband dye solubilisation is probably linked to the carboxyl-functionality or a proton excess. In accordance with the higher solubility of REE-oxides compared to REE-phosphates and -aluminates, the red dye Y2O3:Eu(2+) containing relatively expensive REE was shown to be preferentially solubilized. These results show that it is possible to dissolve the REE-compounds of FP with the help of microbial processes. Moreover, they provide the basis for the development of an eco-friendly alternative to the currently applied methods that use strong inorganic acids or toxic

  15. The rare earth element potential of kaolin deposits in the Bohemian Massif (Czech Republic, Austria)

    NASA Astrophysics Data System (ADS)

    Höhn, S.; Frimmel, H. E.; Pašava, J.

    2014-12-01

    Four kaolin deposits in the Bohemian Massif were studied in order to assess the potential for the recovery of rare earth elements (REE) as by-products from the residue after extraction and refining of the raw kaolin. The behaviour of REE + Y during kaolinitization was found to be largely a function of pre-alteration mineralogy. In the examples studied, i.e. granite-derived deposits of Kriechbaum (Austria) and Božičany, and arkose-derived deposits of Kaznějov and Podbořany (all Czech Republic), the REE + Y are predominantly hosted by monazite which has remained unaffected by kaolinitization. The overall REE + Y content of the variably kaolinitized rocks is strongly dependent on their genesis. While ion adsorption plays only a minor role in the concentration of REE + Y in the studied kaolinitized rocks, the processing and refining of the raw kaolin leads to residues that are enriched in REE + Y by a factor of up to 40. The use of a magnetic separator and a hydrocyclone in the processing of the raw material can yield REE + Y contents of as much as 0.77 wt%. Although this value compares well with the REE + Y concentration in some potentially economic REE + Y projects elsewhere, the overall tonnage of the (REE + Y)-enriched residue is by far not sufficient to consider economic extraction of REE + Y as by-product. Our results are most probably applicable also to other kaolin deposits derived from the weathering of Hercynian basement granites elsewhere (e.g. in Saxonia and Bavaria, Germany). Overall, the potential for REE + Y production as by-product from kaolin mining has to be regarded as minimal.

  16. The Battle for Air Supremacy Over the Somme, 1 June-30 November 1916

    DTIC Science & Technology

    2007-11-02

    Squadron intercepted ten German bombers crossing the lines at Festubert. Flying the lead DH2 was the squadron commander, Major Lionel Rees , who had...won the Military Cross as a flight commander in 1915 flying an FB5 Gunbus with Number 11 Squadron. With Rees in the other DH2, was his wingman, a...Canadian, Lieutenant John Simpson. Simpson and Rees became separated and against 10-to-1 odds, Simpson attacked the German formation. Within seconds

  17. Critical Zone Weathering and Your Smartphone: Understanding How Mineral Decomposition and Colloid Redistribution Can Generate Rare Earth Element Deposits

    NASA Astrophysics Data System (ADS)

    Bern, C.; Foley, N.

    2014-12-01

    Rare earth elements (REE's) are crucial in the manufacture of smartphones and many other high tech devices. Increasing global demand and relatively narrow geographic sourcing have promoted interest in understanding REE deposit genesis and distribution. Highly weathered, clay-hosted, ion-exchange type deposits in southern China are the source of much of the world's production of the more valuable heavy REEs. Such deposits form as REE-bearing minerals weather and REEs released to solution in ionic form are retained by negatively charged exchange sites on clay minerals. We are investigating the potential for ion-exchange REE deposits in the Piedmont of the southeastern United States, where slow erosion rates have preserved thick (up to 20 m) regolith, as required for such deposits. The Liberty Hill pluton outcrops as coarse-grained biotite-amphibole granite and quartz monzonite over nearly 400 km2 in South Carolina, and has an age of 305 Ma (new SHRIMP ion microprobe zircon age). In weathered profiles over the pluton, ion-exchangeable REE content ranges from 8 to 580 ppm and accounts for 2 to 80% of bulk REE content. Elemental and heavy mineral distributions suggest the wide ranging differences in leachability may be attributable to the amount and distribution of resistant REE-bearing phases (e.g., monazite) relative to more easily weathered phases (e.g., allanite) in the parent granite. The REEs show little mobility within the regolith, indicating the effectiveness of the ion-exchange retention mechanism. In contrast, vertical redistribution of colloidal material shows maximum accumulations at ~1 m depth, as traced by the newly developed dual-phase (colloids vs. solution) mass balance model. The contrast suggests redistributed colloidal material has minimal influence on REE mobilization or retention. Conditions and processes necessary for ion-exchange REE deposit development exist in the Piedmont, but their presence will depend upon favorable parent rock mineralogy.

  18. Rare earth element concentrations in geological and synthetic samples using synchrotron X-ray fluorescence analysis

    USGS Publications Warehouse

    Chen, J.R.; Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Rivers, M.L.; Sutton, S.R.; Cygan, G.L.; Grossman, J.N.; Reed, M.J.

    1993-01-01

    The concentrations of rare earth elements (REEs) in specific mineral grains from the Bayan Obo ore deposit and synthetic high-silica glass samples have been measured by synchrotron X-ray fluorescence (SXRF) analysis using excitation of the REE K lines between 33 and 63 keV. Because SXRF, a nondestructive analytical technique, has much lower minimum detection limits (MDLs) for REEs, it is an important device that extends the in situ analytical capability of electron probe microanalysis (EPMA). The distribution of trace amounts of REEs in common rock-forming minerals, as well as in REE minerals and minerals having minor quantities of REEs, can be analyzed with SXRF. Synchrotron radiation from a bending magnet and a wiggler source at the National Synchrotron Light Source, Brookhaven National Laboratory, was used to excite the REEs. MDLs of 6 ppm (La) to 26 ppm (Lu) for 3600 s in 60-??m-thick standard samples were obtained with a 25-??m diameter wiggler beam. The MDLs for the light REEs were a factor of 10-20 lower than the MDLs obtained with a bending magnet beam. The SXRF REE concentrations in mineral grains greater than 25 ??m compared favorably with measurements using EPMA. Because EPMA offered REE MDLs as low as several hundred ppm, the comparison was limited to the abundant light REEs (La, Ce, Pr, Nd). For trace values of medium and heavy REEs, the SXRF concentrations were in good agreement with measurements using instrumental neutron activation analysis (INAA), a bulk analysis technique. ?? 1993.

  19. Geochemical behaviour of rare earths in Vitis vinifera grafted onto different rootstocks and growing on several soils.

    PubMed

    Censi, P; Saiano, F; Pisciotta, A; Tuzzolino, N

    2014-03-01

    The geochemical behaviour of lanthanides and yttrium (Rare Earth Elements, REEs) has been investigated mainly in geological systems where these elements represent the best proxies of processes involving the occurrence of an interface between different media. This behaviour is assessed according to features recorded in sequences of REE concentrations along the REE series normalised with respect to a reference material. In this study, the geochemical behaviour of REE was investigated in different parts of Vitis vinifera specimens grown off-soil, on soils of different nature and grafted onto several rootstocks in order to evaluate effects induced by these changes. The results indicated that roots are the plant organs where REEs are preferentially concentrated, in particular elements from Sm to Ho (middle REE, MREE) whereas Eu enrichments occur in aerial parts. The geochemical behaviour of REE suggests that MREE enrichments in roots are due to preferential MREE interactions with biological membranes or to surface complexation with newly formed phosphates. Eu-positive anomalies suggest that Eu(3+) can form stable organic complexes in place of Ca(2+) in several biological processes in xylem fluids. The possibility that Eu mobility in these fluids can be enhanced by its reductive speciation as Eu(2+) cannot be ruled out. The assessment of the geochemical behaviour of REE according to the theory of the Tetrad Effect carried out confirms that REEs coming from soil are scavenged onto root tissues or mineral surfaces whereas their behaviour in aerial parts of V. vinifera is driven by dissolved complexation.

  20. Pilot Study to Explore the Accuracy of Current Prediction Equations in Assessing Energy Needs of Patients with Newly Diagnosed Glioblastoma Multiforme.

    PubMed

    Little, Rebecca B; Oster, Robert A; Darnell, Betty E; Demark-Wahnefried, Wendy; Nabors, L Burt

    2016-01-01

    Glioblastoma multiforme (GBM) is rare, yet it is the most common brain malignancy and has a poor prognosis. In regard to GBM, there is a dearth of research on resting energy expenditure (REE) and the accuracy of extant prediction equations. The aim of this cross-sectional study was to compare measured REE (mREE) to commonly used prediction equations in newly diagnosed GBM patients. REE was collected by indirect calorimetry in 20 GBM patients. Calculated REE was derived from Harris-Benedict (again with weight adjusted for obesity), Mifflin-St Jeor, and the 20 kcal/kg body weight ratio method. Paired t-tests and Bland-Altman analyses were used to compare group means, evaluate the bias, and find the limits of agreement. Clinical accuracy was assessed by determining the percentage of patients with predicted REE within ±10% of mREE. Subjects were evenly distributed with regard to gender, primarily Caucasian, and largely overweight or obese and had a mean age of 57 years. All equations overestimated mREE. Mifflin-St Jeor and adjusted Harris-Benedict had the narrowest limits of agreement and accurately predicted 60% and 65% of subjects, respectively. Clinicians should be aware of the discrepancy between commonly used prediction equations and REE. More research is needed to verify these findings and decipher the cause and significance in the GBM population.

  1. Origin of heavy rare earth mineralization in South China

    PubMed Central

    Xu, Cheng; Kynický, Jindřich; Smith, Martin P.; Kopriva, Antonin; Brtnický, Martin; Urubek, Tomas; Yang, Yueheng; Zhao, Zheng; He, Chen; Song, Wenlei

    2017-01-01

    Heavy rare earth elements (HREE) are dominantly mined from the weathering crusts of granites in South China. Although weathering processes occur globally, no economic HREE resources of this type have yet been found outside China. Here, we report the occurrence of unidentified REE minerals in the granites from South Chinese deposits. They contain high levels of both HREE and light REE, but are strongly depleted in Ce, implying high oxidation state. These REE minerals show higher initial Nd isotope than primary REE-rich minerals (ɛNd(t)=0.9±0.8 versus −11.5±0.5). The mineralized weathering crusts inherited REE signature of the granites, but show more Ce depletion and more overall concentration of the REE. We propose, therefore, that highly oxidized, REE-rich fluids, derived from external, isotopically depleted sources, metasomatized the granites, which resulted in Ce depletion as Ce4+ and enrichment of the remaining REE, especially the HREE, contributing to formation of a globally important REE resource. PMID:28220784

  2. Average sedimentary rock rare Earth element patterns and crustal evolution: Some observations and implications from the 3800 Ma ISUA supracrustal belt, West Greenland

    NASA Technical Reports Server (NTRS)

    Dymek, R. F.; Boak, J. L.; Gromet, L. P.

    1983-01-01

    Rare earth element (REE) data is given on a set of clastic metasediments from the 3800 Ma Isua Supracrustal belt, West Greenland. Each of two units from the same sedimentary sequence has a distinctive REE pattern, but the average of these rocks bears a very strong resemblance to the REE pattern for the North American Shale Composite (NASC), and departs considerably from previous estimates of REE patterns in Archaean sediments. The possibility that the source area for the Isua sediments resembled that of the NASC is regarded as highly unlikely. However, REE patterns like that in the NASC may be produced by sedimentary recycling of material yielding patterns such as are found at Isua. The results lead to the following tentative conclusions: (1) The REE patterns for Isua Seq. B MBG indicate the existence of crustal materials with fractionated REE and negative Eu anomalies at 3800 Ma, (2) The average Seq. B REE pattern resembles that of the North American Shale Composite (NASC), (3) If the Seq. B average is truly representative of its crustal sources, then this early crust could have been extensively differentiated. In this regard, a proper understanding of the NASC pattern, and its relationship to post-Archaean crustal REE reservoirs, is essential, (4) The Isua results may represent a local effect.

  3. Rare earth and other elements in components of the Abee enstatite chondrite

    NASA Technical Reports Server (NTRS)

    Frazier, R. M.; Boynton, W. V.

    1985-01-01

    Radiochemical and instrumental neutron activation analyses of REEs and other elements have been conducted for Abee clast samples, a matrix sample, a dark inclusion, magnetic and nonmagnetic samples, and bulk samples. Correlations of the REEs and oldhamite abundance for both the clasts and dark inclusions indicate that the REEs chiefly occur in oldhamite. The similar REE patterns for clasts and dark inclusions, and the similar mineral composition of oldhamite in clast and dark inclusions, suggest that the oldhamite in both the clasts and dark inclusions is of a common origin.

  4. Rare earth element components in atmospheric particulates in the Bayan Obo mine region.

    PubMed

    Wang, Lingqing; Liang, Tao; Zhang, Qian; Li, Kexin

    2014-05-01

    The Bayan Obo mine, located in Inner Mongolia, China, is the largest light rare earth body ever found in the world. The research for rare earth elements (REEs) enrichment in atmospheric particulates caused by mining and ore processing is fairly limited so far. In this paper, atmospheric particulates including total suspended particulate (TSP) matter and particles with an equivalent aerodynamic diameter less than 10 μm (PM10) were collected around the Bayan Obo mine region, in August 2012 and March 2013, to analyze the levels and distributions of REEs in particles. The total concentrations of REEs for TSP were 149.8 and 239.6 ng/m(3), and those for PM10 were 42.8 and 68.9 ng/m(3), in August 2012 and March 2013, respectively. Enrichment factor was calculated for all 14 REEs in the TSP and PM10 and the results indicated that REEs enrichment in atmosphere particulates was caused by anthropogenic sources and influenced by the strong wind in springtime. The spatial distribution of REEs in TSP showed a strong gradient concentration in the prevailing wind direction. REE chondrite normalized patterns of TSP and PM10 were similar and the normalized curves inclined to the right side, showing the conspicuous fractionation between the light REEs and heavy REE, which supported by the chondrite normalized concentration ratios calculated for selected elements (La(N)/Yb(N), La(N)/Sm(N), Gd(N)/Yb(N)).

  5. Rare earth element distribution in >400 °C hot hydrothermal fluids from 5°S, MAR: The role of anhydrite in controlling highly variable distribution patterns

    NASA Astrophysics Data System (ADS)

    Schmidt, K.; Garbe-Schönberg, D.; Bau, M.; Koschinsky, A.

    2010-07-01

    Two submarine hydrothermal vent fields at 5°S, Mid-Atlantic Ridge (MAR) - Turtle Pits and Comfortless Cove - emanate vapor-phase fluids at conditions close to the critical point of seawater (407 °C, 298 bars). In this study, the concentration and distribution of rare earth element (REE) and yttrium (Y) has been investigated. Independent of the major element composition, the fluids display a strong temporal variability of their REE + Y concentrations and relative distributions at different time scales of minutes to years. Chondrite-normalized distributions range from common fluid patterns with light REE enrichment relative to the heavy REE, accompanied by positive Eu anomalies (type I), to strongly REE + Y enriched patterns with a concave-downward distribution with a maximum enrichment of Sm and weakly positive or even negative Eu anomalies (type II). The larger the sum of REE, the smaller Ce CN/Yb CN and Eu/Eu∗. We also observed a strong variability in fluid flow and changing fluid temperatures, correlating with the compositional variability. As evident by the positive correlation of total REE, Ca, and Sr concentrations in Turtle Pits and Comfortless Cove fluids, precipitation/dissolution of hydrothermal anhydrite controls the variability in REE concentrations and distributions in these fluids and the transformation of one fluid type to the other. The variable distribution of REE can be explained by the accumulation of particulate anhydrite (with concave-downward REE distribution and negative Eu anomaly) into a fluid with common REE distribution (type I), followed by the modification of the REE fluid signature due to dissolution of incorporated anhydrite. A second model, in which the type II fluids represent a primary REE reaction zone fluid pattern, which is variably modified by precipitation of anhydrite, can also explain the observed correlations of total REE, fractionation of LREE/HREE and size of Eu anomaly as well as Ca, Sr. The emanation of such a fluid

  6. Rare earth element geochemistry of massive sulfides-sulfates and gossans on the Southern Explorer Ridge

    SciTech Connect

    Barrett, T.J. ); Jarvis, I. ); Jarvis, K.E. )

    1990-07-01

    Massive sulfide-sulfate deposits on the Southern Explorer Ridge were analyzed for 14 rare earth elements (REE) by a modified inductively coupled plasma-mass spectrometric technique that included a correction for high Ba content. Bulk samples of finely intermixed sulfides, sulfate, and amorphous silica contain {Sigma}REE concentrations of {le} 6 ppm. REE patterns range from (1) strongly enriched in light REE with positive Eu anomalies, to (2) relatively flat with positive Eu anomalies and slightly negative Ce anomalies, to (3) slightly enriched in light REE with moderately negative Ce anomalies. Pattern 1 is similar to that of 300-350 C solutions discharging at vents on the East Pacific Rise and the Mid-Atlantic Ridge, whereas pattern 3 resembles REE distributions in normal oceanic bottom waters. The sulfide-sulfate patterns are interpreted to result from variable mixtures of hydrothermal and normal seawater. Barite in gossans capping the mounds has an REE pattern almost identical to patterns of high-temperature vent solutions. Hydrothermal barite has lower REE contents and a different REE pattern relative to hydrogenous barite formed slowly on the sea floor.

  7. Precise rare earth analysis of geological materials

    SciTech Connect

    Laul, J.C.; Wogman, N.A.

    1982-01-01

    Rare earth element (REE) concentrations are very informative in revealing chemical fractionation processs in geological systems. The REE's (La-Lu) behavior is characteristic of various primary and secondary minerals which comprise a rock. The REE's contents and their patterns provide a strong fingerprint in distinguishing among various rock types and in understanding the partial melting and/or fractional crystallization of the source region. The REE contents in geological materials are usually at trace levels. To measure all the REE at such levels, radiochemical neutron activation analysis (RNAA) has been used with a REE group separation scheme. To maximize detection sensitivites for individual REE, selective ..gamma..-ray/x-ray measurements have been made using normal Ge(Li) and low-energy photon detectors (LEPD), and Ge(Li)-NaI(Tl) coincidence-noncoincidence spectrometer systems. Using these detection methods an individual REE can be measured at or below the ppB levels; chemical yields of the REE are determined by reactivation.

  8. Generation of abnormal trace element abundances in Antarctic eucrites by weathering processes

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.; Lindstrom, Marilyn M.

    1991-01-01

    Data were obtained on the trace- and major-element compositions of 16 Antarctic abnormal eucrites, many of which exhibiting positive (but sometimes negative) Ce anomalies, positive Eu anomalies, and low abundances of the remainder of the REEs. The results of data analysis suggest that the unusual REE patterns of abnormal Antarctic eucrites arise from weathering effects generated in or on the Antarctic ice. The suggested scenario involves the formation of melt water and its equilibration with the atmosphere, promoting the dissolution of REE-rich phosphates and the oxidation of Ce. As a result, tetravalent Ce is fractionated from the trivalent REE in solution.

  9. Compositional and phase relations among rare earth element minerals

    NASA Technical Reports Server (NTRS)

    Burt, D. M.

    1989-01-01

    A review is presented that mainly treats minerals in which the rare-earth elements are essential constituents, e.g., bastnaesite, monazite, xenotime, aeschynite, allanite. The chemical mechanisms and limits of REE substitution in some rock-forming minerals (zircon, apatite, titanite, garnet) are also derived. Vector representation of complex coupled substitutions in selected REE-bearing minerals is examined and some comments on REE-partitioning between minerals as related to acid-based tendencies and mineral stabilities are presented. As the same or analogous coupled substitutions involving the REE occur in a wide variety of mineral structures, they are discussed together.

  10. Associations among calcium intake, resting energy expenditure, and body fat in a multiethnic sample of children

    PubMed Central

    Hanks, Lynae J.; Casazza, Krista; Willig, Amanda L.; Cardel, Michelle I.; Beasley, T. Mark; Fernandez, Jose R.

    2010-01-01

    Objective The objective was to determine if calcium intake was associated with resting energy expenditure (REE) and body fat in children, after accounting for ancestral genetic background. Study design Participants included 315 children. REE, body composition, and dietary calcium were assessed by indirect calorimetry, dual energy x-ray absorptiometry (DXA), and 24-hour recalls, respectively. Structural equations modeling assessed the relationships among REE, calcium intake and body fat. Results There were positive associations between calcium intake and REE (p<0.01) and between REE and total body fat (p<0.0001). There was indirect effect of calcium intake on total body fat (p<0.01). There were positive associations between calcium intake and REE (p<0.01), and a trend towards an association of calcium intake and total body fat (p=0.065) among males only; whereas, the only significant relationship among females was an association of REE on total body fat (p<0.0001). Conclusions REE was associated with calcium intake and mediated a relationship between calcium intake and total body fat. These findings suggest calcium intake may play a role in fat accumulation and energy balance through its effects on REE, especially in males. PMID:20400090

  11. The rare earth element geochemistry of acid-sulphate and acid-sulphate-chloride geothermal systems from Yellowstone National Park, Wyoming, USA

    NASA Astrophysics Data System (ADS)

    Lewis, Anita J.; Palmer, Martin R.; Sturchio, Neil C.; Kemp, Anthony J.

    1997-02-01

    Rare earth element (REE) concentrations have been determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) in acid-sulphate and acid-sulphate-chloride waters and the associated sinters and volcanic rocks from the Yellowstone National Park (YNP), Wyoming, USA, geothermal system. REE concentrations in the volcanic rocks range from 222 to 347 ppm; their chondite-normalised REE patterns are typical of upper continental crust, with LREE > HREE and negative Eu anomalies. Total REE concentrations in the fluids range from 3 to 1133 nmol kg -1 (≥ 162 ppm), and ΣREE concentrations in sinter are ≥ 181 ppm. REE abundances and patterns in drill core material from YNP indicate some REE mobility. Normalisation of REE concentrations in altered Lava Creek Tuff (LCT) from Y-12 drill core to REE concentrations in fresh LCT indicate that the REE overall have been depleted with the exception of Eu, which has been decoupled from the REE series and concentrated in the altered rocks. Relative to the host rocks the REE patterns of the fluids are variably depleted in HREEs and LREEs, and usually have a pronounced positive Eu anomaly. This decoupling of Eu from the REE suite suggests that (1) Eu has been preferentially removed either from the host rock glass or from the host rock minerals, or (2) the waters are from a high temperature or reducing environment where Eu 2+ is more soluble than the trivalent REEs. Since the latter is inconsistent with production of acid-sulphate springs in a low temperature, oxidising near-surface environment, we suggest that the positive Eu anomalies in the fluids result from preferential dissolution of a Eu-rich phase in the host rock. Spatial and temporal variations in major element chemistry and pH of the springs sampled from Norris Geyser Basin and Crater Hills accompany variations in REE concentrations and patterns of individual geothermal springs. These are possibly related to changes in subsurface plumbing, which results in variations in

  12. Origin of heavy rare earth mineralization in South China.

    PubMed

    Xu, Cheng; Kynický, Jindřich; Smith, Martin P; Kopriva, Antonin; Brtnický, Martin; Urubek, Tomas; Yang, Yueheng; Zhao, Zheng; He, Chen; Song, Wenlei

    2017-02-21

    Heavy rare earth elements (HREE) are dominantly mined from the weathering crusts of granites in South China. Although weathering processes occur globally, no economic HREE resources of this type have yet been found outside China. Here, we report the occurrence of unidentified REE minerals in the granites from South Chinese deposits. They contain high levels of both HREE and light REE, but are strongly depleted in Ce, implying high oxidation state. These REE minerals show higher initial Nd isotope than primary REE-rich minerals (ɛNd(t)=0.9±0.8 versus -11.5±0.5). The mineralized weathering crusts inherited REE signature of the granites, but show more Ce depletion and more overall concentration of the REE. We propose, therefore, that highly oxidized, REE-rich fluids, derived from external, isotopically depleted sources, metasomatized the granites, which resulted in Ce depletion as Ce(4+) and enrichment of the remaining REE, especially the HREE, contributing to formation of a globally important REE resource.

  13. Resting Energy Expenditure Prediction in Recreational Athletes of 18–35 Years: Confirmation of Cunningham Equation and an Improved Weight-Based Alternative

    PubMed Central

    ten Haaf, Twan; Weijs, Peter J. M.

    2014-01-01

    Introduction Resting energy expenditure (REE) is expected to be higher in athletes because of their relatively high fat free mass (FFM). Therefore, REE predictive equation for recreational athletes may be required. The aim of this study was to validate existing REE predictive equations and to develop a new recreational athlete specific equation. Methods 90 (53M, 37F) adult athletes, exercising on average 9.1±5.0 hours a week and 5.0±1.8 times a week, were included. REE was measured using indirect calorimetry (Vmax Encore n29), FFM and FM were measured using air displacement plethysmography. Multiple linear regression analysis was used to develop a new FFM-based and weight-based REE predictive equation. The percentage accurate predictions (within 10% of measured REE), percentage bias, root mean square error and limits of agreement were calculated. Results The Cunningham equation and the new weight-based equation and the new FFM-based equation performed equally well. De Lorenzo's equation predicted REE less accurate, but better than the other generally used REE predictive equations. Harris-Benedict, WHO, Schofield, Mifflin and Owen all showed less than 50% accuracy. Conclusion For a population of (Dutch) recreational athletes, the REE can accurately be predicted with the existing Cunningham equation. Since body composition measurement is not always possible, and other generally used equations fail, the new weight-based equation is advised for use in sports nutrition. PMID:25275434

  14. Bioadsorption of Rare Earth Elements through Cell Surface Display of Lanthanide Binding Tags.

    PubMed

    Park, Dan M; Reed, David W; Yung, Mimi C; Eslamimanesh, Ali; Lencka, Malgorzata M; Anderko, Andrzej; Fujita, Yoshiko; Riman, Richard E; Navrotsky, Alexandra; Jiao, Yongqin

    2016-03-01

    With the increasing demand for rare earth elements (REEs) in many emerging clean energy technologies, there is an urgent need for the development of new approaches for efficient REE extraction and recovery. As a step toward this goal, we genetically engineered the aerobic bacterium Caulobacter crescentus for REE adsorption through high-density cell surface display of lanthanide binding tags (LBTs) on its S-layer. The LBT-displayed strains exhibited enhanced adsorption of REEs compared to cells lacking LBT, high specificity for REEs, and an adsorption preference for REEs with small atomic radii. Adsorbed Tb(3+) could be effectively recovered using citrate, consistent with thermodynamic speciation calculations that predicted strong complexation of Tb(3+) by citrate. No reduction in Tb(3+) adsorption capacity was observed following citrate elution, enabling consecutive adsorption/desorption cycles. The LBT-displayed strain was effective for extracting REEs from the acid leachate of core samples collected at a prospective rare earth mine. Our collective results demonstrate a rapid, efficient, and reversible process for REE adsorption with potential industrial application for REE enrichment and separation.

  15. Effects of rare earth elements on the distribution of mineral elements and heavy metals in horseradish.

    PubMed

    Wang, Lihong; Huang, Xiaohua; Zhou, Qing

    2008-09-01

    In order to investigate the effects of rare earth elements (REEs) on horseradish, the distribution of the mineral elements and heavy metals in different organs of horseradish have been studied by using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Meanwhile, three variable major parameters, namely the concentration of REEs, the type of REEs, and the growth stage of plant were chosen. The results indicated that the test REEs, Ce(III) and Tb(III), could be accumulated in leaves, stems and roots of horseradish. In addition, we found that the content of mineral elements was increased in horseradish treated with 20mgl(-1) of Ce(III), but not those with the 20mgl(-1) of Tb(III). Moreover, the content of mineral elements in horseradish was decreased with the increasing concentration of REEs (100, 300mgl(-1)). Furthermore, we found that there were the opposite effects on the content of the heavy metals in horseradish treated with REEs. Finally, we found that the effect of REEs on the accumulation of REEs, and the content of mineral elements or heavy metals of horseradish during vigorous growth stage, no matter positive or negative, was more obvious than that of the other growth stages. These results demonstrated that the distribution behaviors of mineral elements and heavy metals in horseradish can be affected by the type and concentration of REEs, and the growth period of plant.

  16. Origin of heavy rare earth mineralization in South China

    NASA Astrophysics Data System (ADS)

    Xu, Cheng; Kynický, Jindřich; Smith, Martin P.; Kopriva, Antonin; Brtnický, Martin; Urubek, Tomas; Yang, Yueheng; Zhao, Zheng; He, Chen; Song, Wenlei

    2017-02-01

    Heavy rare earth elements (HREE) are dominantly mined from the weathering crusts of granites in South China. Although weathering processes occur globally, no economic HREE resources of this type have yet been found outside China. Here, we report the occurrence of unidentified REE minerals in the granites from South Chinese deposits. They contain high levels of both HREE and light REE, but are strongly depleted in Ce, implying high oxidation state. These REE minerals show higher initial Nd isotope than primary REE-rich minerals (εNd(t)=0.9+/-0.8 versus -11.5+/-0.5). The mineralized weathering crusts inherited REE signature of the granites, but show more Ce depletion and more overall concentration of the REE. We propose, therefore, that highly oxidized, REE-rich fluids, derived from external, isotopically depleted sources, metasomatized the granites, which resulted in Ce depletion as Ce4+ and enrichment of the remaining REE, especially the HREE, contributing to formation of a globally important REE resource.

  17. Revisiting the rare earth elements in foraminiferal tests [rapid communication

    NASA Astrophysics Data System (ADS)

    Haley, Brian A.; Klinkhammer, Gary P.; Mix, Alan C.

    2005-10-01

    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.

  18. Formation of carbonatite-related giant rare-earth-element deposits by the recycling of marine sediments

    PubMed Central

    Hou, Zengqian; Liu, Yan; Tian, Shihong; Yang, Zhiming; Xie, Yuling

    2015-01-01

    Carbonatite-associated rare-earth-element (REE) deposits are the most significant source of the world’s REEs; however, their genesis remains unclear. Here, we present new Sr-Nd-Pb and C-O isotopic data for Cenozoic carbonatite-hosted giant REE deposits in southwest China. These REE deposits are located along the western margin of the Yangtze Craton that experienced Proterozoic lithospheric accretion, and controlled by Cenozoic strike-slip faults related to Indo-Asian continental collision. The Cenozoic carbonatites were emplaced as stocks or dykes with associated syenites, and tend to be extremely enriched in Ba, Sr, and REEs and have high 87Sr/86Sr ratios (>0.7055). These carbonatites were likely formed by melting of the sub-continental lithospheric mantle (SCLM), which had been previously metasomatized by high-flux REE- and CO2-rich fluids derived from subducted marine sediments. The fertility of these carbonatites depends on the release of REEs from recycled marine sediments and on the intensity of metasomatic REE refertilization of the SCLM. We suggest that cratonic edges, particularly along ancient convergent margins, possess the optimal configuration for generating giant REE deposits; therefore, areas of metamorphic basement bounded or cut by translithospheric faults along cratonic edges have a high potential for such deposits. PMID:26035414

  19. Bioadsorption of rare earth elements through cell surface display of lanthanide binding tags

    SciTech Connect

    Park, Dan M.; Reed, David W.; Yung, Mimi C.; Eslamimanesh, Ali; Lencka, Malgorzata M.; Anderko, Andrzej; Fujita, Yoshiko; Riman, Richard E.; Navrotsky, Alexandra; Jiao, Yongqin

    2016-02-02

    In this study, with the increasing demand for rare earth elements (REEs) in many emerging clean energy technologies, there is an urgent need for the development of new approaches for efficient REE extraction and recovery. As a step toward this goal, we genetically engineered the aerobic bacterium Caulobacter crescentus for REE adsorption through high-density cell surface display of lanthanide binding tags (LBTs) on its S-layer. The LBT-displayed strains exhibited enhanced adsorption of REEs compared to cells lacking LBT, high specificity for REEs, and an adsorption preference for REEs with small atomic radii. Adsorbed Tb3+ could be effectively recovered using citrate, consistent with thermodynamic speciation calculations that predicted strong complexation of Tb3+ by citrate. No reduction in Tb3+ adsorption capacity was observed following citrate elution, enabling consecutive adsorption/desorption cycles. The LBT-displayed strain was effective for extracting REEs from the acid leachate of core samples collected at a prospective rare earth mine. Our collective results demonstrate a rapid, efficient, and reversible process for REE adsorption with potential industrial application for REE enrichment and separation.

  20. Bioadsorption of rare earth elements through cell surface display of lanthanide binding tags

    DOE PAGES

    Park, Dan M.; Reed, David W.; Yung, Mimi C.; ...

    2016-02-02

    In this study, with the increasing demand for rare earth elements (REEs) in many emerging clean energy technologies, there is an urgent need for the development of new approaches for efficient REE extraction and recovery. As a step toward this goal, we genetically engineered the aerobic bacterium Caulobacter crescentus for REE adsorption through high-density cell surface display of lanthanide binding tags (LBTs) on its S-layer. The LBT-displayed strains exhibited enhanced adsorption of REEs compared to cells lacking LBT, high specificity for REEs, and an adsorption preference for REEs with small atomic radii. Adsorbed Tb3+ could be effectively recovered using citrate,more » consistent with thermodynamic speciation calculations that predicted strong complexation of Tb3+ by citrate. No reduction in Tb3+ adsorption capacity was observed following citrate elution, enabling consecutive adsorption/desorption cycles. The LBT-displayed strain was effective for extracting REEs from the acid leachate of core samples collected at a prospective rare earth mine. Our collective results demonstrate a rapid, efficient, and reversible process for REE adsorption with potential industrial application for REE enrichment and separation.« less

  1. Rare earth element distribution in some hydrothermal minerals: evidence for crystallographic control

    USGS Publications Warehouse

    Morgan, J.W.; Wandless, G.A.

    1980-01-01

    Rare earth element (REE) abundances were measured by neutron activation analysis in anhydrite (CaSO4), barite (BaSO4), siderite (FeCO3) and galena (PbS). A simple crystal-chemical model qualitatively describes the relative affinities for REE substitution in anhydrite, barite, and siderite. When normalized to 'crustal' abundances (as an approximation to the hydrothermal fluid REE pattern), log REE abundance is a surprisingly linear function of (ionic radius of major cation-ionic radius of REE)2 for the three hydrothermal minerals, individually and collectively. An important exception, however, is Eu, which is anomalously enriched in barite and depleted in siderite relative to REE of neighboring atomic number and trivalent ionic radius. In principle, REE analyses of suitable pairs of co-existing hydrothermal minerals, combined with appropriate experimental data, could yield both the REE content and the temperature of the parental hydrothermal fluid. The REE have only very weak chalcophilic tendencies, and this is reflected by the very low abundances in galena-La, 0.6 ppb; Sm, 0.06 ppb; the remainder are below detection limits. ?? 1980.

  2. Competition between humic acid and carbonates for rare earth elements complexation.

    PubMed

    Pourret, Olivier; Davranche, Mélanie; Gruau, Gérard; Dia, Aline

    2007-01-01

    The competitive binding of rare earth elements (REE) to humic acid (HA) and carbonates was studied experimentally at various pH and alkalinity values by combining ultrafiltration and inductively coupled plasma mass spectrometry techniques. The results show that the REE species occur as binary humate or carbonate complexes but not as ternary REE-carbonate-humate as previously proposed. The results also reveal the strong pH and alkalinity dependence of the competition as well as the existence of a systematic fractionation across the REE series. Specifically, carbonate complexation is at a maximum at pH 10 and increase with increasing alkalinity and with the atomic number of the REE (LuCO(3)>LaCO(3)). Modeling of the data using Model VI and recently published stability constants for complexation of REE by humic acid well reproduced the experimental data, confirming the ability of Model VI to accurately determine REE speciation in natural waters. This modeling also confirms the reliability of recently published stability constants. This work shed more light not only on the competition between carbonates and HA for REE complexation but also on the reliability of WHAM 6 and Model VI for calculating the speciation of REE with organic matter in alkaline organic-rich water.

  3. The 'North American shale composite' - Its compilation, major and trace element characteristics

    NASA Technical Reports Server (NTRS)

    Gromet, L. P.; Dymek, R. F.; Haskin, L. A.; Korotev, R. L.

    1984-01-01

    North American shale composite (NASC) major element composition and compilation are presented, together with rare earth element (REE) redeterminations obtained by high precision analytical methods. The major element composition of the NASC compares closely with other average shale compositions, and significant portions of the REE and some other trace elements are contained in minor phases. The uneven REE distribution in NASC powder appears to yield the heterogeneity in analyzed aliquants. REE distributions of detrital sediments may to some extent be dependent on their minor mineral assemblages and the sedimentological factors controlling these assemblages.

  4. LA-ICP-MS analysis of isolated phosphatic grains indicates selective rare earth element enrichment during reworking and transport processes

    NASA Astrophysics Data System (ADS)

    Auer, Gerald; Reuter, Markus; Hauzenberger, Christoph A.; Piller, Werner E.

    2016-04-01

    Rare earth elements (REE) are a commonly used proxy to reconstruct water chemistry and oxygen saturation during the formation history of authigenic and biogenic phosphates in marine environments. In the modern ocean REE exhibit a distinct pattern with enrichment of heavy REE and strong depletion in Cerium. Studies of ancient phosphates and carbonates, however, showed that this 'modern' pattern is only rarely present in the geological past. Consequently, the wide range of REE enrichment patterns found in ancient marine phosphates lead to the proposition that water chemistry had to have been radically different in the earth's past. A wealth of studies has already shown that both early and late diagenesis can strongly affect REE signatures in phosphates and severely alter primary marine signals. However, no previous research was conducted on how alteration processes occurring prior to final deposition affect marine phosphates. Herein we present a dataset of multiple LA-ICP-MS measurements of REE signatures in isolated phosphate and carbonate grains deposited in a carbonate ramp setting in the central Mediterranean Sea during the middle Miocene "Monterey event". The phosphates are represented by authigenic, biogenic and detrital grains emplaced in bioclastic grain- to packstones dominated by bryozoan and echinoderm fragments, as well as abundant benthic and planktic foraminifers. The results of 39 grain specific LA-ICP-MS measurements in three discrete rock samples reveals four markedly different REE patterns (normalized to the Post Archean Australian Shale standard) in terms of total enrichment and pattern shape. Analyses of REE diagenesis proxies show that diagenetic alteration affected the samples only to a minor degree. Considering grain shape and REE patterns together indicate that authigenic, detrital and biogenic phosphates have distinct REE patterns irrespective of the sample. Our results show that the observed REE patterns in phosphates only broadly reflect

  5. Investigating Rare Earth Element Systematics in the Marcellus Shale

    NASA Astrophysics Data System (ADS)

    Yang, J.; Torres, M. E.; Kim, J. H.; Verba, C.

    2014-12-01

    The lanthanide series of elements (the 14 rare earth elements, REEs) have similar chemical properties and respond to different chemical and physical processes in the natural environment by developing unique patterns in their concentration distribution when normalized to an average shale REE content. The interpretation of the REE content in a gas-bearing black shale deposited in a marine environment must therefore take into account the paleoredox conditions of deposition as well as any diagenetic remobilization and authigenic mineral formation. We analyzed 15 samples from a core of the Marcellus Shale (Whipkey ST1, Greene Co., PA) for REEs, TOC, gas-producing potential, trace metal content, and carbon isotopes of organic matter in order to determine the REE systematics of a black shale currently undergoing shale gas development. We also conducted a series of sequential leaching experiments targeting the phosphatic fractions in order to evaluate the dominant host phase of REEs in a black shale. Knowledge of the REE system in the Marcellus black shale will allow us to evaluate potential REE release and behavior during hydraulic fracturing operations. Total REE content of the Whipkey ST1 core ranged from 65-185 μg/g and we observed three distinct REE shale-normalized patterns: middle-REE enrichment (MREE/MREE* ~2) with heavy-REE enrichment (HREE/LREE ~1.8-2), flat patterns, and a linear enrichment towards the heavy-REE (HREE/LREE ~1.5-2.5). The MREE enrichment occurred in the high carbonate samples of the Stafford Member overlying the Marcellus Formation. The HREE enrichment occurred in the Union Springs Member of the Marcellus Formation, corresponding to a high TOC peak (TOC ~4.6-6.2 wt%) and moderate carbonate levels (CaCO3 ~4-53 wt%). Results from the sequential leaching experiments suggest that the dominant host of the REEs is the organic fraction of the black shale and that the detrital and authigenic fractions have characteristic MREE enrichments. We present our

  6. Rare Earth Elements in Global Aqueous Media

    NASA Astrophysics Data System (ADS)

    Noack, C.; Karamalidis, A.; Dzombak, D. A.

    2012-12-01

    We are examining the occurrence and abundance of rare earth elements (REE) associated with produced waters from shale gas development, and factors controlling aqueous REE concentrations in geochemical environments, to provide information for: (1) potential recovery of REE as a valuable byproduct, and (2) utilization of unique REE signatures as a risk assessment tool. REE include the lanthanide series of elements - excluding short-lived, radioactive promethium - and yttrium. These elements are critical to a wide variety of high-tech, energy efficient applications such as phosphors, magnets, and batteries. Escalating costs of REE resulting from divergent supply and demand patterns motivates the first goal. The second goal relates to the search for a reliable, naturally occurring tracer to improve understanding of fluid migration and water-rock interactions during hydraulic fracturing and natural gas recovery. We compiled data from 100 studies of REE occurrence and concentrations in groundwaters, ocean waters, river waters, and lake waters. In the groundwater systems documented, total dissolved REE concentrations ranged over eight orders of magnitude; however the average concentrations across the lanthanides varied by less than two orders of magnitude. This leads to exceptional inter-element correlations, with a median correlation coefficient greater than 0.98, implying potential usefulness of REE ratios for groundwater signatures. Reports describing reactions governing REE solubilization were also investigated. We assembled information about important solution chemistries and performed equilibrium modeling using PHREEQC to examine common hypotheses regarding the factors controlling REE compositions. In particular, effects of pH, Eh, and common complexing ligands were evaluated. Produced and connate waters of the Marcellus shale are well characterized for their major chemical elements. There is a dearth of knowledge, however, regarding the occurrence of REE in

  7. Rare earth element metasomatism in hydrothermal systems: The Willsboro-Lewis wollastonite ores, New York, USA

    USGS Publications Warehouse

    Whitney, P.R.; Olmsted, J.F.

    1998-01-01

    Wollastonite ores and garnet-pyroxene skarns in the Willsboro-Lewis district, New York, USA were formed in a complex hydrothermal system associated with the emplacement of a large anorthosite pluton. Contact-metamorphic marbles were replaced by wollastonite, garnet, and clinopyroxene during infiltration metasomatism involving large volumes of water of chiefly meteoric origin. Rare earth elements (REE) in these rocks show large departures from the protolith REE distribution, indicative of substantial REE mobility. Three types of chondrite-normalized REE distribution patterns are present. The most common, found in ores and skarns containing andradite-rich garnet, is convex-up in the light REE (LREE) with a maximum at Pr and a positive Eu anomaly. Europium anomalies and Pr/Yb ratios are correlated with X(Ad) in garnet. This pattern (type C) results from uptake of REE from hydrothermal fluids by growing crystals of calcsilicate minerals, principally andradite, with amounts of LREE controlled by the difference in ionic radius between Ca++ and REE3+ in garnet X sites. The Eu anomaly results either from prior interaction of the fluids with plagioclase-rich, Eu-positive anorthositic rocks in and near the ore zone, or by enrichment of divalent Eu on growth surfaces of garnet followed by entrapment, or both. Relative enrichment in heavy REE (type H) occurs in ores and skarn where calcsilicates, including grossularitic garnet, in contact-metamorphic marble have been concentrated by dissolution of calcite. In most cases a negative Eu anomaly is inherited from the marble protolith. Skarns containing titanite and apatite exhibit high total REE, relative light REE enrichment, and negative Eu anomalies (type L). These appear to be intrusive igneous rocks (ferrodiorites or anorthositic gabbros) that have been converted to skarn by Ca metasomatism. REE, sequestered in titanite, apatite, and garnet, preserve the approximate REE distribution pattern of the igneous protolith. Post

  8. The impact of transport processes on rare earth element patterns in marine authigenic and biogenic phosphates

    NASA Astrophysics Data System (ADS)

    Auer, Gerald; Reuter, Markus; Hauzenberger, Christoph A.; Piller, Werner E.

    2017-04-01

    Rare earth elements (REEs) are commonly used proxies to reconstruct water chemistry and oxygen saturation during the formation of authigenic and biogenic phosphates in marine environments. In the modern ocean REEs exhibit a distinct pattern with enrichment of heavy REEs and strong depletion in cerium (Ce). The wide range of REE enrichment patterns found in ancient marine phosphates lead to the proposition that water chemistry has been very different in the Earth's past. However, both early and late diagenesis are known to affect REE signatures in phosphates altering primary marine signals. Herein we present a dataset of REE signatures in 38 grain specific LA-ICP-MS measurements of isolated phosphate and carbonate grains in three discrete rock samples. The phosphates mainly consist of authigenic phosphates and phosphatized microfossils that formed in a microbially mediated micro-milieu. In addition, isolated biogenic and reworked phosphatic grains are also present. The phosphates are emplaced in bioclastic grain- to packstones deposited on a carbonate ramp setting in the central Mediterranean Sea during the middle Miocene Monterey event. The results reveal markedly different REE patterns (normalized to the Post Archean Australian Shale standard) in terms of total enrichment and pattern shape. Analyses of REE diagenesis proxies show that diagenetic alteration affected the samples only to a minor degree. Grain shape and REE patterns together indicate that authigenic, biogenic and reworked phosphates have distinct REE patterns irrespective of the sample. Our study shows that while REE patterns in phosphates do reflect water chemistry during authigenesis, they are often already heavily altered during reworking, a process, which can occur in geologically negligible timespans. REE patterns are therefore more likely to reflect complex enrichment processes after their formation. Similarities in the REE patterns of reworked and biogenic phosphate further suggest that the

  9. Diel behavior of rare earth elements in a mountain stream with acidic to neutral pH

    NASA Astrophysics Data System (ADS)

    Gammons, Christopher H.; Wood, Scott A.; Nimick, David A.

    2005-08-01

    Diel (24-h) changes in concentrations of rare earth elements (REE) were investigated in Fisher Creek, a mountain stream in Montana that receives acid mine drainage in its headwaters. Three simultaneous 24-h samplings were conducted at an upstream station (pH = 3.3), an intermediate station (pH = 5.5), and a downstream station (pH = 6.8). The REE were found to behave conservatively at the two upstream stations. At the downstream station, REE partitioned into suspended particles to a degree that varied with the time of day, and concentrations of dissolved REE were 2.9- to 9.4-fold (190% to 830%) higher in the early morning vs. the late afternoon. The decrease in dissolved REE concentrations during the day coincided with a corresponding increase in the concentration of REE in suspended particles, such that diel changes in the total REE concentrations were relatively minor (27% to 55% increase at night). Across the lanthanide series, the heavy REE partitioned into the suspended solid phase to a greater extent than the light REE. Filtered samples from the downstream station showed a decrease in shale-normalized REE concentration across the lanthanide series, with positive anomalies at La and Gd, and a negative Eu anomaly. As the temperature of the creek increased in the afternoon, the slope of the REE profile steepened and the magnitude of the anomalies increased. The above observations are explained by cyclic adsorption of REE onto suspended particles of hydrous ferric and aluminum oxides (HFO, HAO). Conditional partition coefficients for each REE between the suspended solids and the aqueous phase reached a maximum at 1700 hours and a minimum at 0700 hours. This pattern is attributed to diel variations in stream temperature, possibly reinforced by kinetic factors (i.e., slower rates of reaction at night than during the day). Estimates of the enthalpy of adsorption of each REE onto suspended particles based on the field results averaged +82 kJ/mol and are similar in

  10. Diel behavior of rare earth elements in a mountain stream with acidic to neutral pH

    USGS Publications Warehouse

    Gammons, C.H.; Wood, S.A.; Nimick, D.A.

    2005-01-01

    Diel (24-h) changes in concentrations of rare earth elements (REE) were investigated in Fisher Creek, a mountain stream in Montana that receives acid mine drainage in its headwaters. Three simultaneous 24-h samplings were conducted at an upstream station (pH = 3.3), an intermediate station (pH = 5.5), and a downstream station (pH = 6.8). The REE were found to behave conservatively at the two upstream stations. At the downstream station, REE partitioned into suspended particles to a degree that varied with the time of day, and concentrations of dissolved REE were 2.9- to 9.4-fold (190% to 830%) higher in the early morning vs. the late afternoon. The decrease in dissolved REE concentrations during the day coincided with a corresponding increase in the concentration of REE in suspended particles, such that diel changes in the total REE concentrations were relatively minor (27% to 55% increase at night). Across the lanthanide series, the heavy REE partitioned into the suspended solid phase to a greater extent than the light REE. Filtered samples from the downstream station showed a decrease in shale-normalized REE concentration across the lanthanide series, with positive anomalies at La and Gd, and a negative Eu anomaly. As the temperature of the creek increased in the afternoon, the slope of the REE profile steepened and the magnitude of the anomalies increased. The above observations are explained by cyclic adsorption of REE onto suspended particles of hydrous ferric and aluminum oxides (HFO, HAO). Conditional partition coefficients for each REE between the suspended solids and the aqueous phase reached a maximum at 1700 hours and a minimum at 0700 hours. This pattern is attributed to diel variations in stream temperature, possibly reinforced by kinetic factors (i.e., slower rates of reaction at night than during the day). Estimates of the enthalpy of adsorption of each REE onto suspended particles based on the field results averaged +82 kJ/mol and are similar in

  11. Rare earth element geochemistry of oceanic ferromanganese nodules and associated sediments

    NASA Astrophysics Data System (ADS)

    Elderfield, H.; Hawkesworth, C. J.; Greaves, M. J.; Calvert, S. E.

    1981-04-01

    Analyses have been made of REE contents of a well-characterized suite of deep-sea (> 4000 m.) principally todorokite-bearing ferromanganese nodules and associated sediments from the Pacific Ocean. REE in nodules and their sediments are closely related: nodules with the largest positive Ce anomalies are found on sediments with the smallest negative Ce anomalies; in contrast, nodules with the highest contents of other rare earths (3 + REE) are found on sediments with the lowest 3 + REE contents and vice versa. 143Nd /144Nd ratios in the nodules (˜0.51244) point to an original seawater source but an identical ratio for sediments in combination with the REE patterns suggests that diagenetic reactions may transfer elements into the nodules. Analysis of biogenic phases shows that the direct contribution of plankton and carbonate and siliceous skeletal materials to REE contents of nodules and sediments is negligible. Inter-element relationships and leaching tests suggest that REE contents are controlled by a P-rich phase with a REE pattern similar to that for biogenous apatite and an Fe-rich phase with a pattern the mirror image of that for sea water. It is proposed that 3 + REE concentrations are controlled by the surface chemistry of these phases during diagenetic reactions which vary with sediment accumulation rate. Processes which favour the enrichment of transition metals in equatorial Pacific nodules favour the depletion of 3 + REE in nodules and enrichment of 3 + REE in associated sediments. In contrast, Ce appears to be added both to nodules and sediments directly from seawater and is not involved in diagenetic reactions.

  12. The sedimentary flux of dissolved rare earth elements to the ocean

    NASA Astrophysics Data System (ADS)

    Abbott, April N.; Haley, Brian A.; McManus, James; Reimers, Clare E.

    2015-04-01

    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 × 106 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 × 106 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.

  13. Rare earth elements in the phosphatic-enriched sediment of the Peru shelf

    USGS Publications Warehouse

    Piper, D.Z.; Baedecker, P.A.; Crock, J.G.; Burnett, W.C.; Loebner, B.J.

    1988-01-01

    Apatite-enriched materials from the Peru shelf have been analyzed for their major oxide and rare earth element (REE) concentrations. The samples consist of (1) the fine fraction of sediment, mostly clay material, (2) phosphatic pellets and fish debris, which are dispersed throughout the fine-grained sediment, (3) tabular-shaped phosphatic crusts, which occur within the uppermost few centimeters of sediment, and (4) phosphatic nodules, which occur on the seafloor. The bulk REE concentrations of the concretions suggest that these elements are partitioned between the enclosed detrital material and the apatite fraction. Analysis of the fine-grained sediment with which the samples are associated suggested that this detrital fraction in the concretions should have shale REE values; the analysis of the fish debris suggested that the apatite fraction might have seawater values. The seawater contribution of REE's is negligible in the nodules and crust, in which the apatite occurs as a fine-grained interstitial cement. That is, the concentration of REE's and the REE patterns are predominantly a function of the amount of enclosed fine-grained sediment. By contrast, the REE pattern of the pelletal apatite suggests a seawater source and the absolute REE concentrations are relatively high. The REE P2O5 ratios of the apatite fraction of these samples thus vary from approximately zero (in the case of the crust and nodules) to as much as approximately 1.2 ?? 10-3 (in the case of the pellets). The range of this ratio suggests that rather subtle variations in the depositional environment might cause a significant variation in the REE content of this authigenic fraction of the sediment. Pelletal glauconite was also recovered from one sediment core. Its REE concentrations closely resemble those of the fish debris. ?? 1988.

  14. Attenuation of rare earth elements in a boreal estuary

    NASA Astrophysics Data System (ADS)

    Åström, Mats E.; Österholm, Peter; Gustafsson, Jon Petter; Nystrand, Miriam; Peltola, Pasi; Nordmyr, Linda; Boman, Anton

    2012-11-01

    This study focuses on attenuation of rare earth elements (REE) when a boreal creek, acidified and loaded with REE and other metals as a result of wetland drainage, empties into a brackish-water estuary (salinity < 6‰). Surface water was collected in a transect from the creek mouth to the outer estuary, and settling (particulate) material in sediment traps moored at selected locations in the estuary. Ultrafiltration, high-resolution ICP-MS and modeling were applied on the waters, and a variety of chemical reagents were used to extract metals from the settling material. Aluminium, Fe and REE transported by the acidic creek were extensively removed in the inner/central estuary where the acidic water was neutralised, whereas Mn was relatively persistent in solution and thus redistributed to particles and deposited further down the estuary. The REE removal was caused by several contemporary mechanisms: co-precipitation with oxyhydroxides (mainly Al but also Fe), complexation with flocculating humic substances and sorption to suspended particles. Down estuary the dissolved REE pool, remaining after removal, was fractionated: the <1 kDa pool became depleted in the middle REE and the colloidal (0.45 μm-1 kDa) pool depleted in the middle and heavy REE. This fractionation was controlled by the removal process, such that those REE with highest affinity for the settling particles became most depleted in the remaining dissolved pool. Modeling, based on Visual MINTEQ version 3.0 and the Stockholm Humic Model after revision and updating, predicted that the dissolved (<0.45 μm) REE pool in the estuary is bound almost entirely to humic substances. Acid sulphate soils, the source of the REE and other metals in the creek water, are widespread on coastal plains worldwide and therefore the REE attenuation patterns and mechanisms identified in the studied estuary are relevant for recognition of similar geochemical processes and conditions in a variety of coastal locations.

  15. Rare earth element partitioning between hydrous ferric oxides and acid mine water during iron oxidation

    USGS Publications Warehouse

    Verplanck, P.L.; Nordstrom, D.K.; Taylor, H.E.; Kimball, B.A.

    2004-01-01

    Ferrous iron rapidly oxidizes to Fe (III) and precipitates as hydrous Fe (III) oxides in acid mine waters. This study examines the effect of Fe precipitation on the rare earth element (REE) geochemistry of acid mine waters to determine the pH range over which REEs behave conservatively and the range over which attenuation and fractionation occur. Two field studies were designed to investigate REE attenuation during Fe oxidation in acidic, alpine surface waters. To complement these field studies, a suite of six acid mine waters with a pH range from 1.6 to 6.1 were collected and allowed to oxidize in the laboratory at ambient conditions to determine the partitioning of REEs during Fe oxidation and precipitation. Results from field experiments document that even with substantial Fe oxidation, the REEs remain dissolved in acid, sulfate waters with pH below 5.1. Between pH 5.1 and 6.6 the REEs partitioned to the solid phases in the water column, and heavy REEs were preferentially removed compared to light REEs. Laboratory experiments corroborated field data with the most solid-phase partitioning occurring in the waters with the highest pH. ?? 2004 Elsevier Ltd. All rights reserved.

  16. InfoXtract: A Customizable Intermediate Level Information Extraction Engine

    DTIC Science & Technology

    2003-01-01

    Clearforest (www.clearforest.com), SIFT from BBN [Miller et al 1998], REES from SRA [Aone & Ramon- Santacruz 1998] and various tools provided by Inxight... Santacruz 1998] REES: A Large-Scale Relation and Event Extraction System. url: http://acl.ldc.upenn.edu/A/A00/A00-1011.pdf [Chinchor & Marsh 1998

  17. Metabolic Effects of Nicotine Gum and Cigarette Smoking: Potential Implications for Postcessation Weight Gain?

    ERIC Educational Resources Information Center

    Klesges, Robert C.; And Others

    1991-01-01

    Twenty smoking women participated in nicotine gum and smoking administration, after which resting energy expenditures (REEs) were measured. Results indicated acute increase in REE for both nicotine gum and cigarettes. Metabolic rates for nicotine gum slowly returned to baseline; rates for cigarettes quickly fell significantly below baseline.…

  18. 7 CFR 550.16 - Project development.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Project development. 550.16 Section 550.16 Agriculture... § 550.16 Project development. REE provides partial funding to Cooperators to support research projects... the REE Agency's ADODR shall jointly develop the following documentation: (a) Project plan. A...

  19. Rare earths behaviour during the deposition of volcanic sublimates

    NASA Astrophysics Data System (ADS)

    Censi, P.; Sortino, F.; Zuddas, P.; Saiano, F.; Brusca, L.; Chiavetta, S.; Falcone, E. E.

    2017-02-01

    In this study, the REE distribution between volcanic fluids and related solids in fumaroles with temperatures ranging from approximately 100 to 421 °C was investigated in different geological scenarios. The treatment of geochemical REE data was carried out by calculating the REE enrichment factors (EFREE) relative to the volcanic host rocks in studied sites under the assumption that the REE transport takes place as silicate aerosol in volcanic fluids. Shale-normalised REE concentrations in these fluids have been assessed to investigate whether the REE transport as aqueous complexes in water-saturated volcanic gas is reasonable. The REE behaviour in alkaline condensates according to the above mentioned treatments of geochemical data is very similar, being characterised by positive Ce and Gd anomalies and significant W-type tetrad effects. These evidences suggest that the geochemical behaviour of REE in fumarolic fluids is firstly influenced by the sublimate deposition along the fumarolic conduit or around the vents rather than by the transport mechanism of these elements in volcanic fluids.

  20. Planktonic foraminiferal rare earth elements as a potential new aeolian dust proxy

    NASA Astrophysics Data System (ADS)

    Chou, C.; Liu, Y.; Lo, L.; Wei, K.; Shen, C.

    2012-12-01

    Characteristics of rare earth elements (REEs) have widely been used as important tracers in many fields of earth sciences, including lithosphere research, environmental change, ocean circulation and other natural carbonate materials. Foraminiferal test REE signatures have been suggested to reflect ambient seawater conditions and serve as valuable proxies in the fields of paleoceanography and paleoclimate. Here we present a 60-kyr planktonic foraminifera Globigerinoides ruber (white, 250-300 μm) REE record of a sediment core MD05-2925 (9°20.61'S, 151°27.61'E, water depth 1660 m) from the Solomon Sea. The REE diagram shows two dominant sources of local seawater and nearby terrestrial input. The variability of foraminiferal REE/Ca time series is different from Mg/Ca-inferred sea surface temperature and δ18O records during the past 60-kyr. This inconsistency suggests that planktonic foraminiferal REE content cannot result only from changes in ice volume and temperature. Synchroneity between high planktonic foraminiferal REE content and Antarctic ice core dust amount record implies the same dust sources, probably from Australia or mainland China. Our results suggest that foraminiferal REE can potentially be as a new dust proxy and record dry/humid conditions at the source area.

  1. Interactions between exogenous rare earth elements and phosphorus leaching in packed soil columns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rare earth elements (REEs) increasingly used in agriculture as an amendment for crop growth may help to lessen environmental losses of phosphorus (P) from heavily fertilized soils. The vertical transport characteristics of P and REEs, lanthanum (La), neodymium (Nd), samarium (Sm), and cerium (Ce), w...

  2. Distribution of rare earth elements in marine sediments from the Strait of Sicily (western Mediterranean Sea): evidence of phosphogypsum waste contamination.

    PubMed

    Tranchida, G; Oliveri, E; Angelone, M; Bellanca, A; Censi, P; D'Elia, M; Neri, R; Placenti, F; Sprovieri, M; Mazzola, S

    2011-01-01

    Concentrations of rare earth elements (REE), Y, Th and Sc were recently determined in marine sediments collected using a box corer along two onshore-offshore transects located in the Strait of Sicily (Mediterranean Sea). The REE+Y were enriched in offshore fine-grained sediments where clay minerals are abundant, whereas the REE+Y contents were lower in onshore coarse-grained sediments with high carbonate fractions. Considering this distribution trend, the onshore sediments in front of the southwestern Sicilian coast represent an anomaly with high REE+Y concentrations (mean value 163.4 μg g(-1)) associated to high Th concentrations (mean value 7.9 μg g(-1)). Plot of shale-normalized REE+Y data of these coastal sediments showed Middle REE enrichments relative to Light REE and Heavy REE, manifested by a convexity around Sm-Gd-Eu elements. These anomalies in the fractionation patterns of the coastal sediments were attributed to phosphogypsum-contaminated effluents from an industrial plant, located in the southern Sicilian coast.

  3. Origin and distribution of rare earth elements in various lichen and moss species over the last century in France.

    PubMed

    Agnan, Y; Séjalon-Delmas, N; Probst, A

    2014-07-15

    Rare earth elements (REE) are known to be powerful environmental tracers in natural biogeochemical compartments. In this study, the atmospheric deposition of REE was investigated using various lichens and mosses as well as herbarium samples from 1870 to 1998 from six major forested areas in France. The comparison between the REE distribution patterns in organisms and bedrocks showed a regional uniformity influence from dust particles originating from the bedrock and/or soil weathering that were entrapped by lichens and mosses. These lithological signatures were consistent over the last century. The REE patterns of different organism species allowed minor influence of the species to be highlighted compared to the regional lithology. This was even true where the morphological features played a role in the bioaccumulation levels, which were related to the variable efficiency in trapping atmospheric dust particles. A comparison between REE profiles in the organisms and bark indicated a lack of influence of the substrate on lichen REE content. Lichens and mosses appear to be robust passive monitors of REE atmospheric deposition over decades because the mineral data was preserved in herbarium samples despite organic degradation being shown by carbon isotopes and SEM observations. To overcome the bias of REE concentration that resulted from organic degradation, the use of a normalized method is recommended to interpret the historical samples.

  4. Recycling rare earth elements from industrial wastewater with flowerlike nano-Mg(OH)(2).

    PubMed

    Li, Chaoran; Zhuang, Zanyong; Huang, Feng; Wu, Zhicheng; Hong, Yangping; Lin, Zhang

    2013-10-09

    Treatment of wastewater containing low-concentration yet highly-expensive rare earth elements (REEs) is one of the vital issues in the REEs separation and refining industry. In this work, the interaction and related mechanism between self-supported flowerlike nano-Mg(OH)2 and low-concentration REEs wastewater were investigated. More than 99% REEs were successfully taken up by nano-Mg(OH)2. Further analysis revealed that the REEs could be collected on the surface of Mg(OH)2 as metal hydroxide nanoparticles (<5 nm). An ion-exchange model was proposed as a critical factor for both guaranteeing the reaction speed and maintaining the self-supported structure of the materials. In addition, a method was developed to further separate the immobilized REEs and the residual magnesium hydroxide by varying the solution pH. In a pilot-scale experiment, the REEs from practical wastewater were immobilized effectively at a high flow rate. We anticipate this work can provide a good example for the recycling of valuable REEs in practical industrial applications.

  5. Rare earth element geochemistry of outcrop and core samples from the Marcellus Shale

    DOE PAGES

    Noack, Clinton W.; Jain, Jinesh C.; Stegmeier, John; ...

    2015-06-26

    In this paper, we studied the geochemistry of the rare earth elements (REE) in eleven outcrop samples and six, depth-interval samples of a core from the Marcellus Shale. The REE are classically applied analytes for investigating depositional environments and inferring geochemical processes, making them of interest as potential, naturally occurring indicators of fluid sources as well as indicators of geochemical processes in solid waste disposal. However, little is known of the REE occurrence in the Marcellus Shale or its produced waters, and this study represents one of the first, thorough characterizations of the REE in the Marcellus Shale. In thesemore » samples, the abundance of REE and the fractionation of REE profiles were correlated with different mineral components of the shale. Namely, samples with a larger clay component were inferred to have higher absolute concentrations of REE but have less distinctive patterns. Conversely, samples with larger carbonate fractions exhibited a greater degree of fractionation, albeit with lower total abundance. Further study is necessary to determine release mechanisms, as well as REE fate-and-transport, however these results have implications for future brine and solid waste management applications.« less

  6. Rare earth element geochemistry of outcrop and core samples from the Marcellus Shale

    SciTech Connect

    Noack, Clinton W.; Jain, Jinesh C.; Stegmeier, John; Hakala, J. Alexandra; Karamalidis, Athanasios K.

    2015-06-26

    In this paper, we studied the geochemistry of the rare earth elements (REE) in eleven outcrop samples and six, depth-interval samples of a core from the Marcellus Shale. The REE are classically applied analytes for investigating depositional environments and inferring geochemical processes, making them of interest as potential, naturally occurring indicators of fluid sources as well as indicators of geochemical processes in solid waste disposal. However, little is known of the REE occurrence in the Marcellus Shale or its produced waters, and this study represents one of the first, thorough characterizations of the REE in the Marcellus Shale. In these samples, the abundance of REE and the fractionation of REE profiles were correlated with different mineral components of the shale. Namely, samples with a larger clay component were inferred to have higher absolute concentrations of REE but have less distinctive patterns. Conversely, samples with larger carbonate fractions exhibited a greater degree of fractionation, albeit with lower total abundance. Further study is necessary to determine release mechanisms, as well as REE fate-and-transport, however these results have implications for future brine and solid waste management applications.

  7. Applications Development for a Parallel COTS Spaceborne Computer

    NASA Technical Reports Server (NTRS)

    Katz, Daniel S.; Springer, Paul L.; Granat, Robert; Turmon, Michael

    2000-01-01

    This presentation reviews the Remote Exploration and Experimentation Project (REE) program for utilization of scalable supercomputing technology in space. The implementation of REE will be the use of COTS hardware and software to the maximum extent possible, keeping overhead low. Since COTS systems will be used, with little or no special modification, there will be significant cost reduction.

  8. Shaker Table Experiments with Rare Earth Elements Sorption from Geothermal Brine

    DOE Data Explorer

    Gary Garland

    2015-07-21

    This dataset described shaker table experiments ran with sieved -50 +100 mesh media #1 in brine #1 that have 2ppm each of the 7 REE metals at different starting pH's of 3.5, 4.5, and 5.5. The experimental conditions are 2g media to 150mL of REE solution, at 70C.

  9. Levels of rare earth elements, heavy metals and uranium in a population living in Baiyun Obo, Inner Mongolia, China: a pilot study.

    PubMed

    Hao, Zhe; Li, Yonghua; Li, Hairong; Wei, Binggan; Liao, Xiaoyong; Liang, Tao; Yu, Jiangping

    2015-06-01

    The Baiyun Obo deposit is the world's largest rare earth elements (REE) deposit. We aimed to investigate levels of REE, heavy metals (HMs) and uranium (U) based on morning urine samples in a population in Baiyun Obo and to assess the possible influence of rare earth mining processes on human exposure. In the mining area, elevated levels were found for the sum of the concentrations of light REE (LREE) and heavy REE (HREE) with mean values at 3.453 and 1.151 μg g(-1) creatinine, which were significantly higher than those in the control area. Concentrations of HMs and U in the population increased concomitantly with increasing REE levels. The results revealed that besides REE, HMs and U were produced with REE exploitation. Gender, age, educational level, alcohol and smoking habit were major factors contributing to inter-individual variation. Males were more exposed to these metals than females. Concentrations in people in the senior age group and those with only primary education were low. Drinking and smoking were associated with the levels of LREE, Cr, Cu, Cd and Pb in morning urine. Hence this study provides basic and useful information when addressing public and environmental health challenges in the areas where REE are mined and processed.

  10. Examination of rare earth element concentration patterns in freshwater fish tissues.

    PubMed

    Mayfield, David B; Fairbrother, Anne

    2015-02-01

    Rare earth elements (REEs or lanthanides) were measured in ten freshwater fish species from a reservoir in Washington State (United States). The REE distribution patterns were examined within fillet and whole body tissues for three size classes. Total concentrations (ΣREE) ranged from 0.014 to 3.0 mg kg(-1) (dry weight) and averaged 0.243 mg kg(-1) (dry weight). Tissue concentration patterns indicated that REEs accumulated to a greater extent in organs, viscera, and bone compared to muscle (fillet) tissues. Benthic feeding species (exposed to sediments) exhibited greater concentrations of REEs than pelagic omnivorous or piscivorous fish species. Decreasing REE concentrations were found with increasing age, total length or weight for largescale and longnose suckers, smallmouth bass, and walleye. Concentration patterns in this system were consistent with natural conditions without anthropogenic sources of REEs. These data provide additional reference information with regard to the fate and transport of REEs in freshwater fish tissues in a large aquatic system.

  11. 7 CFR 550.16 - Project development.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Project development. 550.16 Section 550.16 Agriculture... § 550.16 Project development. REE provides partial funding to Cooperators to support research projects... the REE Agency's ADODR shall jointly develop the following documentation: (a) Project plan. A...

  12. 7 CFR 550.16 - Project development.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Project development. 550.16 Section 550.16 Agriculture... § 550.16 Project development. REE provides partial funding to Cooperators to support research projects... the REE Agency's ADODR shall jointly develop the following documentation: (a) Project plan. A...

  13. 7 CFR 550.16 - Project development.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Project development. 550.16 Section 550.16 Agriculture... § 550.16 Project development. REE provides partial funding to Cooperators to support research projects... the REE Agency's ADODR shall jointly develop the following documentation: (a) Project plan. A...

  14. The Presidential Address 2013: Promoting Enthusiasm, Imparting Knowledge! Science for the General Population and Science for Future Researchers Must All Start in the School Curriculum

    ERIC Educational Resources Information Center

    Rees, Martin

    2013-01-01

    This article provides a transcript of the Presidential Address delivered by Martin Rees, Lord Rees of Ludlow, to the Association for Science Education (ASE) Annual Conference at the University of Reading, January 2013. The address is divided into five sections under the following headings: (1) Three Reasons Why the ASE's Mission Is So Important;…

  15. Tracing sediment movement on semi-arid watershed using Rare Earth Elements 1988

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A multi-tracer method employing rare earth elements (REE) was used to determine sediment yield and to track sediment movement in a small semiarid watershed. A 0.33 ha watershed near Tombstone, AZ was divided into five morphological units, each tagged with one of five REE oxides. Relative contributi...

  16. Geochemistry of the rare earth elements in ferromanganese nodules from DOMES Site A, northern equatorial Pacific

    USGS Publications Warehouse

    Calvert, S.E.; Piper, D.Z.; Baedecker, P.A.

    1987-01-01

    The distribution of rare earth elements (REE) in ferromanganese nodules from DOMES Site A has been determined by instrumental neutron activation methods. The concentrations of the REE vary markedly. Low concentrations characterize samples from a depression (the valley), in which Quaternary sediments are thin or absent; high concentrations are found in samples from the surrounding abyssal hills (the highlands) where the Quaternary sediment section is relatively thick. Moreover, the valley nodules are strongly depleted in the light trivalent REE (LREE) and Ce compared with nodules from the highlands, some of the former showing negative Ce anomalies. The REE abundances in the nodules are strongly influenced by the REE abundances in coexisting bottom water. Some controls on the REE chemistry of bottom waters include: a) the more effective removal of the LREE relative to the HREE from seawater because of the greater degree of complexation of the latter elements with seawater ligands, b) the very efficient oxidative scavenging of Ce on particle surfaces in seawater, and c) the strong depletion of both Ce and the LREE in, or a larger benthic flux of the HREE into, the Antarctic Bottom Water (AABW) which flows through the valley. The distinctive REE chemistry of valley nodules is a function of their growth from geochemically evolved AABW. In contrast, the REE chemistry of highland nodules indicates growth from a local, less evolved seawater source. ?? 1987.

  17. Urinary monitoring of exposure to yttrium, scandium, and europium in male Wistar rats.

    PubMed

    Kitamura, Yasuhiro; Usuda, Kan; Shimizu, Hiroyasu; Fujimoto, Keiichi; Kono, Rei; Fujita, Aiko; Kono, Koichi

    2012-12-01

    On the assumption that rare earth elements (REEs) are nontoxic, they are being utilized as replacements of toxic heavy metals in novel technological applications. However, REEs are not entirely innocuous, and their impact on health is still uncertain. In the past decade, our laboratory has studied the urinary excretion of REEs in male Wistar rats given chlorides of europium, scandium, and yttrium solutions by one-shot intraperitoneal injection or oral dose. The present paper describes three experiments for the suitability and appropriateness of a method to use urine for biological monitoring of exposure to these REEs. The concentrations of REEs were determined in cumulative urine samples taken at 0-24 h by inductively coupled plasma atomic emission spectroscopy, showing that the urinary excretion of REEs is <2 %. Rare earth elements form colloidal conjugates in the bloodstream, which make high REEs accumulation in the reticuloendothelial system and glomeruli and low urinary excretion. The high sensitivity of inductively coupled plasma-argon emission spectrometry analytical methods, with detection limits of <2 μg/L, makes urine a comprehensive assessment tool that reflects REE exposure. The analytical method and animal experimental model described in this study will be of great importance and encourage further discussion for future studies.

  18. Rare earth element geochemistry of outcrop and core samples from the Marcellus Shale.

    PubMed

    Noack, Clinton W; Jain, Jinesh C; Stegmeier, John; Hakala, J Alexandra; Karamalidis, Athanasios K

    2015-01-01

    In this work, the geochemistry of the rare earth elements (REE) was studied in eleven outcrop samples and six, depth-interval samples of a core from the Marcellus Shale. The REE are classically applied analytes for investigating depositional environments and inferring geochemical processes, making them of interest as potential, naturally occurring indicators of fluid sources as well as indicators of geochemical processes in solid waste disposal. However, little is known of the REE occurrence in the Marcellus Shale or its produced waters, and this study represents one of the first, thorough characterizations of the REE in the Marcellus Shale. In these samples, the abundance of REE and the fractionation of REE profiles were correlated with different mineral components of the shale. Namely, samples with a larger clay component were inferred to have higher absolute concentrations of REE but have less distinctive patterns. Conversely, samples with larger carbonate fractions exhibited a greater degree of fractionation, albeit with lower total abundance. Further study is necessary to determine release mechanisms, as well as REE fate-and-transport, however these results have implications for future brine and solid waste management applications.

  19. Rare Earth Element Measurements of Melilite and Fassaite in Allende Cai by Nanosims

    NASA Technical Reports Server (NTRS)

    Ito, M.; Messenger, Scott

    2009-01-01

    The rare earth elements (REEs) are concentrated in CAIs by approx. 20 times the chondritic average [e.g., 1]. The REEs in CAIs are important to understand processes of CAI formation including the role of volatilization, condensation, and fractional crystallization [1,2]. REE measurements are a well established application of ion microprobes [e.g., 3]. However the spatial resolution of REE measurements by ion microprobe (approx.20 m) is not adequate to resolve heterogeneous distributions of REEs among/within minerals. We have developed methods for measuring REE with the NanoSIMS 50L at smaller spatial scales. Here we present our initial measurements of REEs in melilite and fassaite in an Allende Type-A CAI with the JSC NanoSIMS 50L. We found that the key parameters for accurate REE abundance measurements differ between the NanoSIMS and conventional SIMS, in particular the oxide-to-element ratios, the relative sensitivity factors, the energy distributions, and requisite energy offset. Our REE abundance measurements of the 100 ppm REE diopside glass standards yielded good reproducibility and accuracy, 0.5-2.5 % and 5-25 %, respectively. We determined abundances and spatial distributions of REEs in core and rim within single crystals of fassaite, and adjacent melilite with 5-10 m spatial resolution. The REE abundances in fassaite core and rim are 20-100 times CI abundance but show a large negative Eu anomaly, exhibiting a well-defined Group III pattern. This is consistent with previous work [4]. On the other hand, adjacent melilite shows modified Group II pattern with no strong depletions of Eu and Yb, and no Tm positive anomaly. REE abundances (2-10 x CI) were lower than that of fassaite. These patterns suggest that fassaite crystallized first followed by a crystallization of melilite from the residual melt. In future work, we will carry out a correlated study of O and Mg isotopes and REEs of the CAI in order to better understand the nature and timescales of its

  20. Rare earth elements as a fingerprint of soil components solubilization

    NASA Astrophysics Data System (ADS)

    Davranche, M.; Grybos, M.; Gruau, G.; Pédrot, M.; Dia, A.

    2009-04-01

    The retention of rare earth element (REE) in the soil profile are mainly controlled by three factors, (i) the stability of the primary REE-carrying minerals, (ii) the presence of secondary phases as clays and Fe- and Mn-oxyhydroxides and (ii) the concentration of colloidal organic matter (OM). Considering that each soil phases (mineral or organic) displays (ii) various surface properties, such as specific area, surface sites density and nature and (ii) their own REE distribution inherited from the rock weathering, their mobilization through various chemical reactions (dissolution, colloidal release….) may involve the development of various shaped REE patterns in the soil solutions. REE fractionation from the different soil phases may therefore be used to identify the response of the soil system to a particular chemical process such as reductive and/or acidic dissolution. To test this purpose, an organic-rich wetland soil sample was incubated under anaerobic condition at both pH 5 and uncontrolled pH. The REE patterns developed in the soil solution were then compared to the REE patterns obtained through either aerobic at pH 3 and 7 incubations or a chemical reduction experiment (using hydroxylamine). REE patterns in anaerobic and aerobic at pH 7 experiments exhibited the same middle rare earth element (MREE) downward concavity significant of the complexation of REE with soil OM. By contrast, under acidic condition, the REE pattern exhibited a positive Eu anomaly due to the dissolution of soil feldspar. Finally, REE pattern obtained from the chemical reducing experiment showed an intermediary flat shape corresponding to a mixing between the soil organic and mineral phases dissolution. The comparison of the various REE pattern shapes allowed to conclude that (i) biological reduction of wetland soil involved amorphous Fe(III) colloids linked to OM and, (ii) that the REE mobility was controlled by the dynamic of OM in wetland soil. They also evidence the potential of

  1. Resting Energy Expenditure in Adults with Becker’s Muscular Dystrophy

    PubMed Central

    Jacques, Matthew F.; Orme, Paul; Smith, Jonathon; Morse, Christopher I.

    2017-01-01

    Purpose The purpose of this study was: 1) To compare Resting energy expenditure (REE) in adult males with Becker’s Muscular Dystrophy (BeMD, n = 21, 39 ±12 years) and healthy controls (CTRL, n = 12, 37 ±12 years) 2) Determine whether other physiological parameters correlate with REE in BeMD, and 3) Compare current prediction methods of REE with measured REE. Methods REE was calculated via indirect calorimetry using continuous, expired gas analysis following an overnight fast. Fat free mass (FFM) and fat mass were measured by bioelectrical impedance. B-mode ultrasound measured Tibialis Anterior (TA) and Gastrocnemius Medialis (GM) anatomical cross sectional area (ACSA). The Bone Specific Physical Activity Questionnaire measured physical activity. Results No difference in REE was found between CTRL and BeMD groups (1913 ±203 & 1786 ±324 Kcal respectively). Other physiological comparisons showed increased fat mass (+54%), decreased TA ACSA (-42%), increased GM ACSA (+25%) as well as reduced respiratory function (FVC -28%; FEV1−27%) in BeMD adults compared to controls. REE estimated from prediction equations (Schofield’s) in Muscular Dystrophy were different from measured REE (P<0.05, bias = -728kcal), while the Mifflin equation was no different from measured REE (r2 = 0.58, Bias = -8kcal). Within the present BeMD, REE predicted from FFM (REE = FFM x 34.57–270; r2 = 0.85) and body mass (REE = BM x 15.65 + 421.5; r2 = 0.66), were not different from measured REE (bias equals 0 and 0.2kcals, respectively) Conclusions Despite no differences in REE between CTRL and BeMD adults, increased fat masses highlights the requirement for explicit nutritional guidelines, as well as maintenance of physical activity levels, where possible. Prediction equations are frequently used in clinical settings, however these have been shown to be less accurate in BeMD; therefore, the equations proposed here should be used where possible. PMID:28060911

  2. Rare earth element behavior during groundwater-seawater mixing along the Kona Coast of Hawaii

    NASA Astrophysics Data System (ADS)

    Johannesson, Karen H.; Palmore, C. Dianne; Fackrell, Joseph; Prouty, Nancy G.; Swarzenski, Peter W.; Chevis, Darren A.; Telfeyan, Katherine; White, Christopher D.; Burdige, David J.

    2017-02-01

    Groundwater and seawater samples were collected from nearshore wells and offshore along the Kona Coast of the Big Island of Hawaii to investigate rare earth element (REE) behavior in local subterranean estuaries. Previous investigations showed that submarine groundwater discharge (SGD) is the predominant flux of terrestrial waters to the coastal ocean along the arid Kona Coast of Hawaii. Groundwater and seawater samples were filtered through 0.45 μm and 0.02 μm pore-size filters to evaluate the importance of colloidal and soluble (i.e., truly dissolved ionic species and/or low molecular weight [LMW] colloids) fractions of the REEs in the local subterranean estuaries. Mixing experiments using groundwater collected immediately down gradient from a wastewater treatment facility (WWTF) proximal to the Kaloko-Hanokohau National Historic Park, and more "pristine" groundwater from a well constructed in a lava tube at Kiholo Bay, were conducted with local seawater to study the effect of solution composition (i.e., pH, salinity) on the concentrations and fractionation behavior of the REEs as groundwater mixes with seawater in Kona Coast subterranean estuaries. The mixed waters were also filtered through 0.45 or 0.02 μm filters to ascertain the behavior of colloidal and soluble fractions of the REEs across the salinity gradient in each mixing experiment. Concentrations of the REEs were statistically identical (two-tailed Student t-test, 95% confidence) between the sequentially filtered sample aliquots, indicating that the REEs occur as dissolved ionic species and/or LMW colloids in Kona Coast groundwaters. The mixing experiments revealed that the REEs are released to solution from suspended particles or colloids when Kona Coast groundwater waters mix with local seawater. The order of release that accompanies increasing pH and salinity follows light REE (LREE) > middle REE (MREE) > heavy REE (HREE). Release of REEs in the mixing experiments is driven by decreases in the

  3. Residual levels of rare earth elements in freshwater and marine fish and their health risk assessment from Shandong, China.

    PubMed

    Yang, Luping; Wang, Xining; Nie, Hongqian; Shao, Lijun; Wang, Guoling; Liu, Yongjun

    2016-06-15

    The total concentrations of rare earth elements (ΣREE) were quantified in 251 samples from 10 common species of freshwater and marine fish in seventeen cities of Shandong, China. ΣREE obtained from the freshwater fish ranged from 34.0 to 37.9ngg(-1) (wet weight) and marine fish from 12.7 to 37.6ngg(-1). The ratio of LREE to HREE was 13.7:1 and 10:1 for freshwater and marine fish, respectively. This suggests that freshwater fish exhibit greater REE concentrations than marine fish and the biological effects of LREE are higher than HREE. Results revealed a similar REE distribution pattern between those fish and coastal sediments, abiding the "abundance law". The health risk assessment demonstrated the EDIs of REEs in fish were significantly lower than the ADI, indicating that the consumption of these fish presents little risk to human health.

  4. Resting Energy Expenditure and Systolic Blood Pressure Relationships in Women Across 4.5 Years

    PubMed Central

    Sriram, Neeraj; Hunter, Gary R.; Fisher, Gordon; Brock, David W.

    2014-01-01

    Recent studies have reported a strong association between blood pressure (BP) and resting energy expenditure (REE). However, it is not known if this relationship persists over time. Therefore, we examined the temporal relationship between REE and systolic BP. Additionally, we examined the impact of sympathetic tone and anthropometric variables on this relationship. All testing was performed on healthy, overweight African American and European American women aged 25 – 45 years over 4.5 years in the UAB General Clinical Research Center. Repeated measures mixed-models revealed REE as a significant determinant of systolic BP (β=0.0155, P<0.0001), independent of catecholamines, leg fat, visceral fat, fat free mass, fat mass, height, RSMI, and resting heart rate. Observations that REE is predictive of systolic BP across 4.5 years support previous findings that REE may potentially mediate resting BP, independent of anthropometric variables and a marker for sympathetic tone. PMID:24548382

  5. Phosphates in pallasite meteorites as probes of mantle processes in small planetary bodies

    NASA Technical Reports Server (NTRS)

    Davis, Andrew M.; Olsen, Edward J.

    1991-01-01

    Trace element analyses of the phosphates minerals in stony-iron pallasite meteorites are used here to investigate the magmatic history of the silicate portions of pallasites. In Eagle Station and seven other pallasites, the phosphates have relatively low concentrations of REEs and are strongly enriched in heavy relative to light REE. These patterns are consistent with formation of phosphate by subsolidus reactions between metal and silicate, in which phosphate inherits the REE pattern of olivine. In Springwater and Santa Rosalia, calcium-rich phosphates have higher concentrations of REE, are enriched in light relative to heavy REE, and have negative europium anomalies. These patterns are consistent with crystallization of phosphate from a europium-depleted chondritic liquid. This is unlikely to have happened near the base of the differentiating parent-body mantle; it suggests that some pallasites may come from regions of their parent bodies much nearer the surface than the core-mantle boundary.

  6. Rare earth element carriers in the Shergotty meteorite and implications for its chronology

    NASA Technical Reports Server (NTRS)

    Lundberg, Laura L.; Crozaz, Ghislaine; Zinner, Ernst; Mckay, Gordon

    1988-01-01

    This paper reports on the results of ion-probe measurements of REE concentrations in individual grains of the Shergotty meteorite. The phases analyzed included whitlockite, apatite, baddeleyite, augite, pigeonite, maskelynite, and K-rich glass; the whitlockite and apatite phases were also analyzed for U. Results indicate that whitlockite contains the bulk of the REE in Shergotty, with no evidence for distinct light-REE patterns in texturally different whitlockites. The results on the evolution of the REE abundances in the Shergotty late-stage interstitial melt, inferred from the analysis of whitlockite, are consistent with closed system crystallization. No metasomatic alteration is required to explain the REE data. It is concluded that there is no compelling reason to attribute chronological significance to the Sm-Nd array, as was done by Jagoutz and Waenke (1986).

  7. Changes in Resting Energy Expenditure in Relation to Body Weight and Composition Following Gastric Restriction: A Systematic Review.

    PubMed

    Browning, Matthew G; Franco, Robert L; Cyrus, John C; Celi, Francesco; Evans, Ronald K

    2016-07-01

    In comparison to gastric bypass surgery, gastric restriction without malabsorption more closely simulates dietary adherence while still producing durable weight loss. The latter is achieved despite considerable reductions in resting energy expenditure (REE), and whether REE is adjusted for body weight/composition using ratio- or regression-based methods could influence understanding of how these procedures affect energy balance. This systematic review identified studies that reported REE before and after gastric restriction in order to compare changes using each method. Ratio assessments revealed increases and decreases when REE was expressed per kilogram of body weight and per kilogram of fat-free mass, respectively. In comparison, measured REE tended to be less than predicted from linear regression after surgery. Explanations for these seemingly disparate findings and future directions are discussed.

  8. Rare earth element behavior during groundwater – seawater mixing along the Kona Coast of Hawaii

    USGS Publications Warehouse

    Johannesson, Karen H.; Palmore, C. Dianne; Fackrell, Joseph; Prouty, Nancy G.; Swarzenski, Peter W.; Chevis, Darren A.; Telfeyan, Katherine; White, Christopher D.; Burdige, David J.

    2017-01-01

    Groundwater and seawater samples were collected from nearshore wells and offshore along the Kona Coast of the Big Island of Hawaii to investigate rare earth element (REE) behavior in local subterranean estuaries. Previous investigations showed that submarine groundwater discharge (SGD) is the predominant flux of terrestrial waters to the coastal ocean along the arid Kona Coast of Hawaii. Groundwater and seawater samples were filtered through 0.45 μm and 0.02 μm pore-size filters to evaluate the importance of colloidal and soluble (i.e., truly dissolved ionic species and/or low molecular weight [LMW] colloids) fractions of the REEs in the local subterranean estuaries. Mixing experiments using groundwater collected immediately down gradient from a wastewater treatment facility (WWTF) proximal to the Kaloko-Hanokohau National Historic Park, and more “pristine” groundwater from a well constructed in a lava tube at Kiholo Bay, were mixed with local seawater to study the effect of solution composition (i.e., pH, salinity) on the concentrations and fractionation behavior of the REEs as groundwater mixes with seawater in Kona Coast subterranean estuaries. The mixed waters were also filtered through 0.45 or 0.02 μm filters to ascertain the behavior of colloidal and soluble fractions of the REEs across the salinity gradient in each mixing experiment. Concentrations of the REEs were statistically identical (two-tailed Student t-test, 95% confidence) between the sequentially filtered sample aliquots, indicating that the REEs occur as dissolved ionic species and/or LMW colloids in Kona Coast groundwaters. The mixing experiments revealed that the REEs are released to solution from suspended particles or colloids when Kona Coast groundwater waters mix with local seawater. The order of release that accompanies increasing pH and salinity follows light REE (LREE) > middle REE (MREE) > heavy REE (HREE). Release of REEs in the mixing experiments is driven by decreases in the

  9. Échange terres rares légères Ca dans l'apatite

    NASA Astrophysics Data System (ADS)

    Iqdari, Abderrahmane; Velde, Bruce; Benalioulhaj, Noureddine; Dujon, Saint-Clair; El Yamine, Nacer

    2003-04-01

    Diffusion experiments were carried out on natural apatite crystals that were immersed in molten light rare earth element (REE) chloride salt at temperatures between 900 and 1150 °C for periods up to 35 days. Electron microprobe analysis of the crystals showed that light REEs replaced Ca according to electronic balance, i.e. 2 REE3+ for 3 Ca2+. These diffusion profiles indicate that a maximum amount of substitution in the structure occurs when two of the ten Ca ions in apatite are replaced by the REE diffusing elements. Anisotropic diffusion is observed between a and c crystallographic directions. Comparison of maximum distance indicates that the larger ions move more easily in the apatite structure. We conclude that the light REEs diffuse within the channel structures of the mineral, and that this diffusion is controlled by the substitution type of elements in the calcium sites. To cite this article: A. Iqdari et al., C. R. Geoscience 335 (2003).

  10. Changes of energy metabolism, nutritional status and serum cytokine levels in patients with Crohn’s disease after anti-tumor necrosis factor-α therapy

    PubMed Central

    Nishida, Nao; Sasaki, Masaya; Kurihara, Mika; Ichimaru, Satomi; Wakita, Maki; Bamba, Shigeki; Andoh, Akira; Fujiyama, Yoshihide; Amagai, Teruyoshi

    2013-01-01

    We investigated the effects of treatment with antibodies against tumor necrosis factor (TNF)-α on energy metabolism, nutritional status, serum cytokine levels in patients with Crohn’s disease (CD). Twelve patients were enrolled. Resting energy expenditure (REE) levels were measured by indirect calorimetry. Crohn’s disease activity index (CDAI) significantly decreased after treatment with anti-TNF-α therapy. Anti-TNF-α therapy did not affect REE, but respiratory quotient (RQ) significantly increased after treatment. Serum interleukin-6 levels were significantly decreased and RQ were significantly increased in high REE (≥25 kcal/kg/day) group as compared to low REE (<25 kcal/kg/day) group. In conclusion, high REE value on admission is a predictive factor for good response to treatment with anti-TNF-α antibodies in active CD patients. PMID:24062610

  11. Uncovering the global life cycles of the rare earth elements.

    PubMed

    Du, Xiaoyue; Graedel, T E

    2011-01-01

    The rare earth elements (REE) are a group of fifteen elements with unique properties that make them indispensable for a wide variety of emerging, critical technologies. Knowledge of the life cycles of REE remains sparse, despite the current heightened interest in their future availability. Mining is heavily concentrated in China, whose monopoly position and potential restriction of exports render primary supplies vulnerable to short and long-term disruption. To provide an improved perspective we derived the first quantitative life cycles (for the year 2007) for ten REE: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), and yttrium (Y). Of these REE, Ce and Nd in-use stocks are highest; the in-use stocks of most REE show significant accumulation in modern society. Industrial scrap recycling occurs only from magnet manufacture. We believe there is no post-customer recycling of any of these elements.

  12. Uncovering the Global Life Cycles of the Rare Earth Elements

    NASA Astrophysics Data System (ADS)

    Du, Xiaoyue; Graedel, T. E.

    2011-11-01

    The rare earth elements (REE) are a group of fifteen elements with unique properties that make them indispensable for a wide variety of emerging, critical technologies. Knowledge of the life cycles of REE remains sparse, despite the current heightened interest in their future availability. Mining is heavily concentrated in China, whose monopoly position and potential restriction of exports render primary supplies vulnerable to short and long-term disruption. To provide an improved perspective we derived the first quantitative life cycles (for the year 2007) for ten REE: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), and yttrium (Y). Of these REE, Ce and Nd in-use stocks are highest; the in-use stocks of most REE show significant accumulation in modern society. Industrial scrap recycling occurs only from magnet manufacture. We believe there is no post-customer recycling of any of these elements.

  13. Bioelectrical activity of the central nervous system among populations in a rare earth element area.

    PubMed

    Zhu, W; Xu, S; Shao, P; Zhang, H; Wu, D; Yang, W; Feng, J

    1997-04-01

    Auditory brainstem electric response (ABR) and somatosensory evoked potential (SEP) of 21 subjects (41 ears) among villagers in a rare earth element (REE) area in Gan County, Jiangxi, China, were studied. No difference in ABR between the subjects from the REE area and the control group was noted. However, the conduction detected by SEP from the median nerve to the thalamus (P15) was shortened (P < 0.05), especially to the first-grade primary somatosensory responsive region (S1) (P < 0.01) and the amplitude of S1 decreased (P < 0.05), indicating that REE was difficult to accumulate in the brainstem, but it was susceptible to cerebral cortex, thus causing sub-clinical damage. This condition was confirmed in the animal experiment. It was suggested that the toxicity through long-term intake of small doses of REE might not be negligible, and the hazard of REE environments should be investigated.

  14. Rare earth elements distribution in grapevine varieties grown on volcanic soils: an example from Mount Etna (Sicily, Italy).

    PubMed

    D'Antone, Carmelisa; Punturo, Rosalda; Vaccaro, Carmela

    2017-04-01

    A geochemical and statistical approach has allowed identifying in rare earth elements (REEs) absorption a good fingerprinting mark for determining the territoriality and the provenance of Vitis vinifera L. in the district of Mount Etna (southern Italy). Our aim is to define the REEs distribution in different parts of the plants which grow in the same volcanic soil and under the same climate conditions, and therefore to assess whether REEs distribution may reflect the composition of the provenance soil or if plants can selectively absorb REEs in order to recognize the fingerprint in the Etna Volcano soils as well as the REEs pattern characteristic of each cultivar of V. vinifera L. The characteristic pattern of REEs has been determined by ICP-MS analyses in the soils and in the selected grapevine varieties for all the following parts: leaves, seeds, juice, skin, and berries. These geochemical criteria, together with the multivariate statistical analysis of the principal component analysis (PCA) and of the linear discriminant analysis (LDA) that can be summarized with the box plot, suggest that leaves mostly absorb REEs than the other parts of the plant. This work investigates the various parts of the plant in order to verify if each grape variety presents a characteristic geochemical pattern in the absorption of REEs in relationship with the geochemical features of the soil so to highlight the individual compositional fingerprint. Based on REE patterns, our study is a useful tool that allows characterizing the differences among the grape varieties and lays the foundation for the use of REEs in the geographic origin of the Mount Etna wine district.

  15. Rare Earth Element Transfer from Soil to Navel Orange Pulp (Citrus sinensis Osbeck cv. Newhall) and the Effects on Internal Fruit Quality

    PubMed Central

    Cheng, Jinjin; Ding, Changfeng; Li, Xiaogang; Zhang, Taolin; Wang, Xingxiang

    2015-01-01

    The effects of soil rare earth element (REE) on navel orange quality and safety in rare earth ore areas have gained great attention. This study investigated the transfer characteristics of REE from soil to navel orange pulp (Citrus sinensis Osbeck cv. Newhall) and examined the effects of soil REE on internal fruit quality in Xinfeng County, Jiangxi province, China. Path analysis showed that soil REE, pH, cation exchange capacity (CEC), and Fe oxide (Feox) significantly affected pulp REE concentrations. A Freundlich-type prediction model for pulp REE was established: log[REEpulp] = -1.036 + 0.272 log[REEsoil] - 0.056 pH - 0.360 log[CEC] + 0.370 log[Feox] (n = 114, R2 = 0.60). From the prediction model, it was inferred that even when soil REE and Feox were as high as 1038 mg kg-1 and 96.4 g kg-1, respectively, and pH and CEC were as low as 3.75 and 5.08 cmol kg-1, respectively, pulp REE concentrations were much lower than the food limit standard. Additionally, soil REE levels were significantly correlated with selected fruit quality indicators, including titratable acidity (r = 0.52, P < 0.01), total soluble solids (r = 0.48, P < 0.01) and vitamin C (r = 0.56, P < 0.01). Generally, under routine methods of water and fertilization management, the cultivation of navel oranges in rare earth ore areas of south China with soil REE ranging from 38.6 to 546 mg kg-1 had improved in internal fruit quality. PMID:25806821

  16. Sympathetic support of energy expenditure and sympathetic nervous system activity after gastric bypass surgery

    PubMed Central

    Curry, Timothy B.; Somaraju, Madhuri; Hines, Casey N.; Groenewald, Cornelius B.; Miles, John M.; Joyner, Michael J.; Charkoudian, Nisha

    2012-01-01

    Resting energy expenditure (REE) is partially dependent on the sympathetic nervous system as evidenced by the fact REE decreases during systemic beta-adrenergic blockade. It is not known how gastric bypass affects the sympathetically mediated component of REE or muscle sympathetic nerve activity (MSNA). We measured REE before and after beta-blockade in female subjects approximately three years post-gastric bypass surgery and in female obese individuals for comparison. We also measured MSNA in a subset of these subjects. The gastric bypass subjects had no change in REE after systemic beta-blockade, reflecting a lack of sympathetic support of REE, in contrast to obese subjects where REE was reduced by beta-blockade by approximately 5% (P<0.05). The gastric bypass subjects, while still overweight (BMI = 29.3 vs 38.0 kg/m2 for obese subjects, P<0.05), also had significantly lower MSNA compared to obese subjects (10.9 ± 2.3 vs. 21.9 ± 4.1 bursts/min, P<0.05). The reasons for low MSNA and a lack of sympathetically mediated support of REE after gastric bypass are likely multifactorial and may be related to changes in insulin sensitivity, body composition, and leptin, among other factors. These findings may have important consequences for the maintenance of weight loss after gastric bypass. Longitudinal studies are needed to further explore the changes in sympathetic support of REE and if changes in MSNA or tissue responsiveness are related to the sympathetic support of REE. PMID:23592656

  17. Distribution of rare earth elements in anionic, cationic and particulate fractions in boreal humus-rich streams affected by acid sulphate soils.

    PubMed

    Aström, Mats; Corin, Nina

    2003-01-01

    The abundance, fractionation and physicochemical forms of rare earth elements (REEs) were determined in five boreal humus-rich streams (dissolved organic carbon, DOC = 14-40 mg/l) affected by acid sulphate soils. The sampling was carried out during high-water flow in autumn when the acid sulphate soils are extensively flushed. The analytical procedures included ion-exchange experiments in field and ICP-MS determination. There was a general decrease in pH (range 4.5-6.2) and increase in the REE concentrations (La range 0.82-23 microg/l) as the proportion of the catchment cover of acid sulphate soils increased, explained by high amounts of REEs in the acidic runoff from such soils. In each stream, four different REE fractions were identified: (1) A cationic fraction, which is dominant in the REE-rich runoff from the acid sulphate soils and which is depleted in HREEs due to hydrochemical and/or geochemical processes, (2) an anionic fraction identified as humus-REE complexes, which in general is more abundant the higher the DOC concentrations and which also becomes increasingly abundant across the lanthanide series, (3) a fraction having a well-developed MREE enrichment, presumably consisting of colloidal REEs, and (4) a minor uncharacterised particle-associated fraction. The REE pool in the streams thus consists of several coexisting and contrasting REE species. The identification and quantification of such species is a prerequisite for the precise and accurate characterisation of the REE hydrochemistry of the streams.

  18. Lunar ferroan anorthosite petrogenesis: clues from trace element distributions in FAN subgroups

    USGS Publications Warehouse

    Floss, C.; James, O.B.; McGee, J.J.; Crozaz, G.

    1998-01-01

    The rare earth elements (REE) and selected other trace elements were measured in plagioclase and pyroxene from nine samples of the lunar ferroan anorthosite (FAN) suite of rocks. Samples were selected from each of four FAN subgroups previously defined by James et al. (1989). Plagioclase compositions are homogeneous within each sample, but high- and low-Ca pyroxenes from lithic clasts typically have different REE abundances from their counterparts in the surrounding granulated matrices. Measured plagioclase/low-Ca pyroxene concentration ratios for the REE have steeper patterns than experimentally determined plagioclase/low-Ca pyroxene partition coefficients in most samples. Textural and trace element evidence suggest that, although subsolidus equilibration may be responsible for some of the discrepancy, plagioclase compositions in most samples have been largely unaffected by intermineral redistribution of the REE. The REE systematics of plagioclase from the four subgroups are broadly consistent with their deviation through crystallization from a single evolving magma. However, samples from some of the subgroups exhibit a decoupling of plagioclase and pyroxene compositions that probably reflects the complexities inherent in crystallization from a large-scale magmatic system. For example, two anorthosites with very magnesian mafic minerals have highly evolved trace element compositions; major element compositions in plagioclase also do not reflect the evolutionary sequence recorded by their REE compositions. Finally, a noritic anorthosite breccia with relatively ferroan mafic minerals contains several clasts with high and variable REE and other trace element abundances. Although plagioclase REE compositions are consistent with their derivation from a magma with a KREEPy trace element signature, very shallow REE patterns in the pyroxenes suggest the addition of a component enriched in the light REE.

  19. Geochemistry of rare earth elements in minesoils from São Domingos mining district (Iberian Pyrite Belt)

    NASA Astrophysics Data System (ADS)

    Delgado, Joaquin; Perez-Lopez, Rafael; Nieto, Jose Miguel; Ayora, Carles

    2010-05-01

    The São Domingos mine is one of the most emblematic mining districts in the lower part of the Guadiana River Basin (SW of Iberian Peninsula). It is located in Portugal (about 5 km from the Spanish border), in the northern sector of the Iberian Pyrite Belt (IPB), one of the largest metallogenetic provinces of massive sulphides in the world. Although mining activity has ceased at present, the large-scale exploitation of this deposit between the second half of the XIX century and the first half of the XX century, has favoured the production of enormous waste dumps, where oxidation of pyrite and associated sulphides is resulting in the production of acid mine drainage (AMD). Mining wastes, minesoils, and acid mine drainage have been analyzed for their major ions and rare earth elements (REE) with the aim of understanding the REE mobility during sulphide weathering so that lanthanoid series can be used both as a proxy for the extent of water-rock interaction and as a tool for identifying impacts of AMD on natural ecosystems. Chemical speciation of REE in extracts from minesoils indicates that REE sulphate complexes (mainly LnSO4+) are the primary aqueous form (60-90%), and free ionic species (Ln3+, 10-40%) are the next most abundant form of soil water-soluble fraction and controls the REE speciation model. The REE from this fraction have NASC-normalized patterns with middle-REE (MREE) enriched signature compared to the light-REE (LREE) and heavy-REE (HREE), showing convex MREE-signatures and convexity index values of +1.29 +/- 1.13. These results are consistent with the typical REE fractionation patterns reported for AMD. Poorly crystalline iron oxyhydroxysulphates act as a source of labile MREE by dissolution and/or desorption processes and could explain the MREE-enriched signatures in solution.

  20. Transfer of rare earth elements from natural metalliferous (copper and cobalt rich) soils into plant shoot biomass of metallophytes from Katanga (Democratic Republic of Congo)

    NASA Astrophysics Data System (ADS)

    Pourret, Olivier; Lange, Bastien; Jitaru, Petru; Mahy, Grégory; Faucon, Michel-Pierre

    2014-05-01

    The geochemical behavior of rare earth elements (REE) is generally assessed for the characterization of the geological systems where these elements represent the best proxies of processes involving the occurrence of an interface between different media. REE behavior is investigated according to their concentrations normalized with respect to the upper continental crust. In this study, the geochemical fingerprint of REE in plant shoot biomass of an unique metallicolous flora (i.e., Crepidorhopalon tenuis and Anisopappus chinensis) was investigated. The plants originate from extremely copper and cobalt rich soils, deriving from Cu and Co outcrops in Katanga, Democratic Republic of Congo. Some of the species investigated in this study are able to accumulate high amounts of Cu and Co in shoot hence being considered as Cu and Co hyperaccumulators. Therefore, assessing the behavior of REE may lead to a better understanding of the mechanisms of metal accumulation by this flora. The data obtained in this study indicate that REE uptake by plants is not primarily controlled by their concentration and speciation in the soil as previously shown in the literature (Brioschi et al. 2013). Indeed, the REE patterns in shoots are relatively flat whereas soils patterns are Middle REE enriched. In addition, it is worth noting that Eu enrichments occur in aerial parts of the plants. These positive Eu anomalies suggest that Eu3 + can form stable organic complexes replacing Ca2 + in several biological processes as in xylem fluids associated with the general nutrient flux. Therefore, is is possible that the Eu mobility in these fluids is enhanced by its reductive speciation as Eu2 +. Eventually, the geochemical behavior of REE illustrates that metals accumulation in aerial parts of C. tenuis and A. chinensis is mainly driven by dissolved complexation. Brioschi, L., Steinmann, M., Lucot, E., Pierret, M., Stille, P., Prunier, J., Badot, P., 2013. Transfer of rare earth elements (REE) from

  1. Using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to explore geochemical taphonomy of vertebrate fossils in the upper cretaceous two medicine and Judith River formations of Montana

    USGS Publications Warehouse

    Rogers, R.R.; Fricke, H.C.; Addona, V.; Canavan, R.R.; Dwyer, C.N.; Harwood, C.L.; Koenig, A.E.; Murray, R.; Thole, J.T.; Williams, J.

    2010-01-01

    Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to determine rare earth element (REE) content of 76 fossil bones collected from the Upper Cretaceous (Campanian) Two Medicine (TMF) and Judith River (JRF) Formations of Montana. REE content is distinctive at the formation scale, with TMF samples exhibiting generally higher overall REE content and greater variability in REE enrichment than JRF samples. Moreover, JRF bones exhibit relative enrichment in heavy REE, whereas TMF bones span heavy and light enrichment fields in roughly equal proportions. TMF bones are also characterized by more negative Ce anomalies and greater U enrichment than JRF bones, which is consistent with more oxidizing diagenetic conditions in the TMF. Bonebeds in both formations show general consistency in REE content, with no indication of spatial or temporal mixing within sites. Previous studies, however, suggest that the bonebeds in question are attritional assemblages that accumulated over considerable time spans. The absence of geochemical evidence for mixing is consistent with diagenesis transpiring in settings that remained chemically and hydrologically stable during recrystallization. Lithology-related patterns in REE content were also compared, and TMF bones recovered from fluvial sandstones show relative enrichment in heavy REE when compared with bones recovered from fine-grained floodplain deposits. In contrast, JRF bones, regardless of lithologic context (sandstone versus mudstone), exhibit similar patterns of REE uptake. This result is consistent with previous reconstructions that suggest that channel-hosted microfossil bonebeds of the JRF developed via the reworking of preexisting concentrations embedded in the interfluve. Geochemical data further indicate that reworked elements were potentially delivered to channels in a recrystallized condition, which is consistent with rapid adsorption of REE postmortem. Copyright ?? 2010, SEPM (Society for

  2. Cracking the Code of Soil Genesis. The Early Role of Rare Earth Elements

    NASA Astrophysics Data System (ADS)

    Zaharescu, D. G.; Dontsova, K.; Burghelea, C. I.; Maier, R. M.; Huxman, T. E.; Chorover, J.

    2014-12-01

    Soil is terrestrial life support system. Its genesis involves tight interactions between biota and mineral surfaces that mobilize structural elements into biogeochemical cycles. Of all chemical elements rare earth elements (REE) are a group of 16 non-nutrient elements of unusual geochemical similarity and present in all components of the surface environment. While much is known about the role of major nutrients in soil development we lack vital understanding of how early biotic colonization affects more conservative elements such as REE. A highly controlled experiment was set up at University of Arizona's Biosphere-2 that tested the effect of 4 biological treatments, incorporating a combination of microbe, grass, mycorrhiza and uninoculated control on REE leaching and uptake in 4 bedrock substrates: basalt, rhyolite, granite and schist. Generally the response of REE to biota presence was synergistic. Variation in total bedrock chemistry could explain major trends in pore water REE. There was a fast transition from chemistry-dominated to a biota dominated environment in the first 3-4 months of inoculation/seeding which translated into increase in REE signal over time. Relative REE abundances in water were generally reflected in plant concentrations, particularly in root, implying that below ground biomass is the main sync of REE in the ecosystem. Mycorrhiza effect on REE uptake in plant organs was significant and increased with infection rates. Presence of different biota translated into subtle differences in REE release, reveling potential biosignatures of biolota-rock colonization. The results thus bring fundamental insight into early stages non-nutrient cycle and soil genesis.

  3. [Study on the contents and fractionation of rare earth elements in filtering water and suspensions in Gansu, Ningxia and Inner Mongolia Sections of Yellow River by HR-ICP-MS].

    PubMed

    Liu, Jing-Jun; Han, Dan; Liu, Ying

    2013-04-01

    In the present paper, high resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS) was applied to analyse the contents of rare earth elements (REE) in the filtering water and suspensions from 12 sampling sites in Gansu, Ningxia and Inner Mongolia Sections of Yellow River, and the fractionation of REE in suspensions was also studied. The results demonstrated that the contents of REE in filtering water were very low, and the element with highest content of elements was La(32.0 ng x L(-1)). The average concentration of total REE (sigmaREE) in filtering water was 47.5 ng x L(-1), and the Baotou-Dengkou (S1) and Sanhuhekou (S2) sampling sites had a higher sigmaREE of 130.0 and 100.0 ng x L(-1), which implied that there might be external REE sources in the filtering water. And in suspensions, the average content of sigmaREE was 167.8 mg x kg(-1), which was similar to the Chinese soil background value. While the heavy rare earth elements (HREE) content in Shenchuanqiao (S11) of Gansu province were significantly higher than other stations, which indicated that it might have external HREE sources. The chondrite-normalized patterns of REE in suspensions from the study area were similar to that of Chinese soil, with light rare earth elements enrichment, and moderate Eu depletion and a bit of Ce depletion. It was showed that the contents of REE in suspensions were mainly from soil weathering.

  4. Moderate to high levels of exercise are associated with higher resting energy expenditure in community-dwelling postmenopausal women.

    PubMed

    Froehle, Andrew W; Hopkins, Susan R; Natarajan, Loki; Schoeninger, Margaret J

    2013-11-01

    Postmenopausal women experience an age-related decline in resting energy expenditure (REE), which is a risk factor for energy imbalance and metabolic disease. Exercise, because of its association with greater lean tissue mass and other factors, has the potential to mediate REE decline, but the relation between exercise and REE in postmenopausal women is not well characterized. This study tests the hypothesis that exercise energy expenditure (EEE) is positively associated with REE and can counter the effects of age and menopause. It involves a cross-sectional sample of 31 healthy postmenopausal women (aged 49-72 years) with habitual exercise volumes at or above levels consistent with current clinical recommendations. Subjects kept exercise diaries for 4 weeks that quantified exercise activity and were measured for body composition, maximal oxygen uptake, and REE. Multiple regression analysis was used to test for associations between EEE, age, body composition, and REE. There was a significant positive relation between EEE and lean tissue mass (fat-free mass and fat-free mass index). The relation between REE and EEE remained significant even after controlling for lean tissue mass. These results support the hypothesis that exercise is positively associated with REE and can counter the negative effects of age and menopause. They also indicate a continuous relation between exercise and REE across ranges of exercise, from moderate to high. Exercise at levels that are at or above current clinical guidelines might, in part, ameliorate the risk for energy imbalance and metabolic disease because of its positive relation with REE.

  5. Automated Quantitative Rare Earth Elements Mineralogy by Scanning Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Sindern, Sven; Meyer, F. Michael

    2016-09-01

    Increasing industrial demand of rare earth elements (REEs) stems from the central role they play for advanced technologies and the accelerating move away from carbon-based fuels. However, REE production is often hampered by the chemical, mineralogical as well as textural complexity of the ores with a need for better understanding of their salient properties. This is not only essential for in-depth genetic interpretations but also for a robust assessment of ore quality and economic viability. The design of energy and cost-efficient processing of REE ores depends heavily on information about REE element deportment that can be made available employing automated quantitative process mineralogy. Quantitative mineralogy assigns numeric values to compositional and textural properties of mineral matter. Scanning electron microscopy (SEM) combined with a suitable software package for acquisition of backscatter electron and X-ray signals, phase assignment and image analysis is one of the most efficient tools for quantitative mineralogy. The four different SEM-based automated quantitative mineralogy systems, i.e. FEI QEMSCAN and MLA, Tescan TIMA and Zeiss Mineralogic Mining, which are commercially available, are briefly characterized. Using examples of quantitative REE mineralogy, this chapter illustrates capabilities and limitations of automated SEM-based systems. Chemical variability of REE minerals and analytical uncertainty can reduce performance of phase assignment. This is shown for the REE phases parisite and synchysite. In another example from a monazite REE deposit, the quantitative mineralogical parameters surface roughness and mineral association derived from image analysis are applied for automated discrimination of apatite formed in a breakdown reaction of monazite and apatite formed by metamorphism prior to monazite breakdown. SEM-based automated mineralogy fulfils all requirements for characterization of complex unconventional REE ores that will become

  6. Rare earth element transfer from soil to navel orange pulp (Citrus sinensis Osbeck cv. Newhall) and the effects on internal fruit quality.

    PubMed

    Cheng, Jinjin; Ding, Changfeng; Li, Xiaogang; Zhang, Taolin; Wang, Xingxiang

    2015-01-01

    The effects of soil rare earth element (REE) on navel orange quality and safety in rare earth ore areas have gained great attention. This study investigated the transfer characteristics of REE from soil to navel orange pulp (Citrus sinensis Osbeck cv. Newhall) and examined the effects of soil REE on internal fruit quality in Xinfeng County, Jiangxi province, China. Path analysis showed that soil REE, pH, cation exchange capacity (CEC), and Fe oxide (Feox) significantly affected pulp REE concentrations. A Freundlich-type prediction model for pulp REE was established: log[REEpulp] = -1.036 + 0.272 log[REEsoil] - 0.056 pH - 0.360 log[CEC] + 0.370 log[Feox] (n = 114, R2 = 0.60). From the prediction model, it was inferred that even when soil REE and Feox were as high as 1038 mg kg-1 and 96.4 g kg-1, respectively, and pH and CEC were as low as 3.75 and 5.08 cmol kg-1, respectively, pulp REE concentrations were much lower than the food limit standard. Additionally, soil REE levels were significantly correlated with selected fruit quality indicators, including titratable acidity (r = 0.52, P < 0.01), total soluble solids (r = 0.48, P < 0.01) and vitamin C (r = 0.56, P < 0.01). Generally, under routine methods of water and fertilization management, the cultivation of navel oranges in rare earth ore areas of south China with soil REE ranging from 38.6 to 546 mg kg-1 had improved in internal fruit quality.

  7. Rare-earth element patterns in conodont albid crowns: Evidence for massive inputs of volcanic ash during the latest Permian biocrisis?

    NASA Astrophysics Data System (ADS)

    Zhao, Laishi; Chen, Zhong-Qiang; Algeo, Thomas J.; Chen, Jianbo; Chen, Yonglin; Tong, Jinnan; Gao, Shan; Zhou, Lian; Hu, Zhaochu; Liu, Yongsheng

    2013-06-01

    Rare-earth element (REE) profiles were generated from conodont bioapatite for two Permian-Triassic boundary sections in South China (Meishan and Daxiakou) in order to investigate environmental changes following the latest Permian mass extinction (LPME). REE concentrations were measured in albid crowns, the conodont histology that is densest and least susceptible to diagenetic alteration, in an effort to recover seawater REE signatures. However, an analysis of REE sources demonstrated that 80-100% of REEs in the study samples were derived from siliciclastic sources, presumably the abundant clay minerals present in the study sections. Interval I (pre-LPME) exhibited lower ΣREE concentrations and distinctly different REE distribution patterns than Intervals II (syn-LPME) and III (post-LPME) of the study sections. REE "fingerprinting" suggests that the latter two intervals contain a large fraction of REEs derived from volcanic clays, characterized by low Eu/Eu* and LaN/YbN and high Th/La ratios. The presence of volcanically derived REEs in post-LPME Interval III indicates that volcanic eruptions continued to spew ash for an extended interval following the boundary crisis or, perhaps more likely, that substantial ash deposits that fell on landmasses during the LPME were slowly eroded and transported to the marine environment. The most probable source of this volcanic ash is the Siberian Traps magmatic province. Ce/Ce* ratios of 0.8-1.0 around the LPME may reflect suboxic to anoxic seawater conditions, although it is uncertain whether Ce in the study sections is mainly of hydrogenous or detrital origin.

  8. The principal rare earth elements deposits of the United States-A summary of domestic deposits and a global perspective

    USGS Publications Warehouse

    Long, Keith R.; Van Gosen, Bradley S.; Foley, Nora K.; Cordier, Daniel

    2010-01-01

    The rare earth elements (REE) are fifteen elements with atomic numbers 57 through 71, from lanthanum to lutetium ('lanthanides'), plus yttrium (39), which is chemically similar to the lanthanide elements and thus typically included with the rare earth elements. Although industrial demand for these elements is relatively small in tonnage terms, they are essential for a diverse and expanding array of high-technology applications. REE-containing magnets, metal alloys for batteries and light-weight structures, and phosphors are essential for many current and emerging alternative energy technologies, such as electric vehicles, energy-efficient lighting, and wind power. REE are also critical for a number of key defense systems and other advanced materials. Section 843 of the National Defense Authorization Act for Fiscal Year 2010, Public Law 111-84, directs the Comptroller General to complete a report on REE materials in the defense supply chain. The Office of Industrial Policy, in collaboration with other U.S. Government agencies, has initiated (in addition to this report) a detailed study of REE. This latter study will assess the Department of Defense's use of REE, as well as the status and security of domestic and global supply chains. That study will also address vulnerabilities in the supply chain and recommend ways to mitigate any potential risks of supply disruption. To help conduct this study, the Office of Industrial Policy asked the U.S. Geological Survey (USGS) to report on domestic REE reserves and resources in a global context. To this end, the enclosed report is the initial USGS contribution to assessing and summarizing the domestic REE resources in a global perspective. In 2009, the Mineral Resources Program of the USGS organized a new project under the title Minerals at Risk and For Emerging Technologies in order to evaluate mineral resource and supply issues of rare metals that are of increasing importance to the national economy. Leaders and members of

  9. Efficient mobilization and fractionation of rare-earth elements by aqueous fluids upon slab dehydration

    NASA Astrophysics Data System (ADS)

    Tsay, A.; Zajacz, Z.; Sanchez-Valle, C.

    2014-07-01

    The characteristic REE fractionation pattern in arc magmas compared to MOR-basalts results from the selective mobilization of light rare-earth elements (LREE) by slab-derived mobile components. However, the nature and composition of the slab flux, and the actual mechanisms responsible for the transfer of rare-earth elements (REE) from the slab to the mantle wedge remain unclear. We present experimental data on the solubility of selected REE in ligand-bearing aqueous fluids and a hydrous haplogranitic melt at 2.6 GPa and 600-800 °C, spanning the conditions relevant to slab dehydration and melting. The solubilities of REE in aqueous fluids increase more than an order of magnitude with temperature increasing from 600 to 800 °C. Addition of ligands such as Cl-, F-, CO32-, SO42- in relatively small concentrations (0.3-1.5 m [mol/kg H2O]) has a pronounced effect further enhancing REE solubilities. Each ligand yields a characteristic REE pattern by preferential dissolution of either the light or the heavy REE. For example, the addition of NaCl to the aqueous fluids yields highly elevated LREE/HREE ratios (La/Yb=17.4±4.3), whereas the addition of fluoride and sulfate ligands significantly increases the solubility of all REE with moderate LREE/HREE fractionation (La/Yb∼4). The addition of Na2CO3 results in preferential increase of HREE solubilities, and yields La/Yb ratio of 1.6±0.5 by flattening the moderately fractionated REE pattern seen in pure aqueous fluids. The solubilities in hydrous haplogranite melt are moderate in comparison to those observed in aqueous fluids and do not lead to pronounced REE fractionation. Therefore, REE can be effectively mobilized and fractionated by aqueous fluids, compared to felsic hydrous melts. Furthermore, the aqueous fluid chemistry has a major role in determining REE mobilities and fractionation upon slab dehydration in addition to the significant control exerted by temperature. Our results show that chloride-bearing slab

  10. Structural differences between light and heavy rare earth element binding chlorophylls in naturally grown fern: Dicranopteris linearis.

    PubMed

    Wei, Zhenggui; Hong, Fashui; Yin, Ming; Li, Huixin; Hu, Feng; Zhao, Guiwen; Wong, Jonathan Woonchung

    2005-09-01

    Chloroplasts and chlorophylls were isolated from the leaves of Dicranopteris linearis, a natural perennial fern sampled at rare earth element (REE) mining areas in the South-Jiangxi region (southern China). The inductively coupled plasma-mass spectrometry (ICP-MS) results indicated that REEs were present in the chloroplasts and chlorophylls of D. linearis. The in vivo coordination environment of light REE (lanthanum) or heavy REE (yttrium) ions in D. linearis chlorophyll-a was determined by the extended X-ray absorption fine structure (EXAFS). Results revealed that there were eight nitrogen atoms in the first coordination shell of the lanthanum atom, whereas there were four nitrogen atoms in the first coordination shell of yttrium. It was postulated that the lanthanum-chlorophyll-a complex might have a double-layer sandwich-like structure, but yttrium-binding chlorophyll-a might be in a single-layer form. Because the content of REE-binding chlorophylls in D. linearis chlorophylls was very low, it is impossible to obtain structural characteristics of REE-binding chlorophylls by direct analysis of the Fourier transform infrared (FTIR) and ultraviolet (UV)-visible spectra of D. linearis chlorophylls. In order to acquire more structural information of REE-binding chlorophyll-a in D. linearis, lanthanum - and yttrium-chlorophyll-a complexes were in vitro synthesized in acetone solution. Element analyses and EXAFS results indicated that REE ions (lanthanum or yttrium) of REE-chlorophyll-a possessed the same coordination environment whether in vivo or in vitro. The FTIR spectra of the REE-chlorophyll-a complexes indicated that REEs were bound to the porphyrin rings of chlorophylls. UV-visible results showed that the intensity ratios of Soret to the Q-band of REE-chlorophyll-a complexes were higher than those of standard chlorophyll-a and pheophytin-a, indicating that REE-chlorophyll-a might have a much stronger ability to absorb the ultraviolet light. The MCD spectrum in

  11. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration

    PubMed Central

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency. PMID:26819083

  12. Rare earth elements and select actinoids in the Canadian House Dust Study.

    PubMed

    Rasmussen, P E; Levesque, C; Chénier, M; Gardner, H D

    2017-03-17

    Nationally representative baseline data are presented for rare earth elements (REE), thorium (Th) and uranium (U) in house dust sampled from 1025 urban homes, in units of concentrations (μg g(-1) ), loadings (μg m(-2) ), and loading rates (ng m(-2)  d(-1) ). Spearman rank correlations indicate that, in addition to outdoor sources, consumer products and building materials can influence indoor dust concentrations of REE, Th, and U. Correlations (P<.01) with numbers of occupants, dogs, and cats suggest soil track-in. Correlations (P<.01) with hardwood floors suggest release of REE additives used in pigments and coatings during daily wear and tear. Concentrations of light REE are elevated in smokers' homes compared to non-smokers' homes (P<.001), suggesting that a key source is "mischmetal," the REE alloy used in cigarette-lighter flints. Indoor sources include geological impurities in raw materials used in consumer products, such as U and Th impurities in bentonite clay used in cat litter, and REE impurities in phosphates used for a variety of applications including dog food and building materials. Median gastric bioaccessibility (pH 1.5) of most REE in dust ranges from about 20% to 29%. Household vacuum samples correlate with fresh dust samples from the same homes (P<.001 for all investigated elements).

  13. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration

    NASA Astrophysics Data System (ADS)

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency.

  14. Preliminary estimates of the quantities of rare-earth elements contained in selected products and in imports of semimanufactured products to the United States, 2010

    USGS Publications Warehouse

    Bleiwas, Donald I.; Gambogi, Joseph

    2013-01-01

    Rare-earth elements (REEs) are contained in a wide range of products of economic and strategic importance to the Nation. The REEs may or may not represent a significant component of that product by mass, value, or volume; however, in many cases, the embedded REEs are critical for the device’s function. Domestic sources of primary supply and the manufacturing facilities to produce products are inadequate to meet U.S. requirements; therefore, a significant percentage of the supply of REEs and the products that contain them are imported to the United States. In 2011, mines in China produced roughly 97 percent of the world’s supply of REEs, and the country’s production of these elements will likely dominate global supply until at least 2020. Preliminary estimates of the types and amount of rare-earth elements, reported as oxides, in semimanufactured form and the amounts used for electric vehicle batteries, catalytic converters, computers, and other applications were developed to provide a perspective on the Nation’s use of these elements. The amount of rare-earth metals recovered from recycling, remanufacturing, and reuse is negligible when the tonnage of products that contain REEs deposited in landfills and retained in storage is considered. Under favorable market conditions, the recovery of REEs from obsolete products could potentially displace a portion of the supply from primary sources.

  15. Size distribution of rare earth elements in coal ash

    USGS Publications Warehouse

    Scott, Clinton T.; Deonarine, Amrika; Kolker, Allan; Adams, Monique; Holland, James F.

    2015-01-01

    Rare earth elements (REEs) are utilized in various applications that are vital to the automotive, petrochemical, medical, and information technology industries. As world demand for REEs increases, critical shortages are expected. Due to the retention of REEs during coal combustion, coal fly ash is increasingly considered a potential resource. Previous studies have demonstrated that coal fly ash is variably enriched in REEs relative to feed coal (e.g, Seredin and Dai, 2012) and that enrichment increases with decreasing size fractions (Blissett et al., 2014). In order to further explore the REE resource potential of coal ash, and determine the partitioning behavior of REE as a function of grain size, we studied whole coal and fly ash size-fractions collected from three U.S commercial-scale coal-fired generating stations burning Appalachian or Powder River Basin coal. Whole fly ash was separated into , 5 um, to 5 to 10 um and 10 to 100 um particle size fractions by mechanical shaking using trace-metal clean procedures. In these samples REE enrichments in whole fly ash ranges 5.6 to 18.5 times that of feedcoals. Partitioning results for size separates relative to whole coal and whole fly ash will also be reported. 

  16. Atmospheric deposition of rare earth elements in Albania studied by the moss biomonitoring technique, neutron activation analysis and GIS technology.

    PubMed

    Allajbeu, Sh; Yushin, N S; Qarri, F; Duliu, O G; Lazo, P; Frontasyeva, M V

    2016-07-01

    Rare earth elements (REEs) are typically conservative elements that are scarcely derived from anthropogenic sources. The mobilization of REEs in the environment requires the monitoring of these elements in environmental matrices, in which they are present at trace level. The determination of 11 REEs in carpet-forming moss species (Hypnum cupressiforme) collected from 44 sampling sites over the whole territory of the country were done by using epithermal neutron activation analysis (ENAA) at IBR-2 fast pulsed reactor in Dubna. This paper is focused on REEs (lanthanides) and Sc. Fe as typical consistent element and Th that appeared good correlations between the elements of lanthanides are included in this paper. Th, Sc, and REEs were never previously determined in the air deposition of Albania. Descriptive statistics were used for data treatment using MINITAB 17 software package. The median values of the elements under investigation were compared with those of the neighboring countries such as Bulgaria, Macedonia, Romania, and Serbia, as well as Norway which is selected as a clean area. Geographical distribution maps of the elements over the sampled territory were constructed using geographic information system (GIS) technology. Geochemical behavior of REEs in moss samples has been studied by using the ternary diagram of Sc-La-Th, Spider diagrams and multivariate analysis. It was revealed that the accumulation of REEs in current mosses is associated with the wind-blowing metal-enriched soils that is pointed out as the main emitting factor of the elements under investigation.

  17. Al-Sm-Eu-Sr systematics of eucrites and moon rocks Implications for planetary bulk compositions

    NASA Technical Reports Server (NTRS)

    Warren, P. H.

    1983-01-01

    Constraints are placed on the bulk compositions of the eucrite parent body (EPB) and the moon through analysis of the Eu and Sr 'anomalies' of eucrites and lunar rooks. It is noted that the elements Al, REE, and Sr are incompatible with the major minerals of these small, low-f(O2) bodies,except for plagioclase. Predictions can be derived about the concentrations of Al, REE, and Sr in samples affected by plagioclase fractionation, based on the hypothesis that these elements in the EPB and moon are all in proportions close to those in the bulk solar system. It is determined that the predictions are almost idealy fulfilled by eucrites and lunar samples. For the EPB, the ratios REE/Al, Sr/Al, and Sr/REE are found to be constrained probably within 10 percent of the chondritic ratios. For the moon, the constraints are found to be less precise: REE/Al is very probably within 25 percent of chondritic; Sr/Al and Sr/REE are probably within 35 percent of chondritic; Sr/Al and Sr/REE are probably within 35 percent of chondritic. It is concluded that there is a very strong similarity between the bulk compositions of the planets and the compositions of chondritic meteorites.

  18. Vitamin D and Calcium-Sensing Receptor polymorphisms differentially associate with resting energy expenditure in peri-pubertal children

    PubMed Central

    Hanks, Lynae J.; Casazza, Krista; Ashraf, Ambika P.; Ramanadham, Sasanka; Ard, Jamy; Bray, Molly S.; Beasley, T. Mark; Fernandez, Jose R.

    2014-01-01

    Given that calcium metabolism is influenced by genes and is tightly linked to energy-utilizing pathways, this study evaluated the association of single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) and calcium-sensing receptor (CASR) with resting energy expenditure (REE). In 273 boys and girls, 7-12y, cross-sectional REE was measured via indirect calorimetry, body composition by DXA, and dietary measures by 24-hour recall. SNPs for VDR Cdx-2 (rs11568820) and CASR A986S (rs1801725) were genotyped using the Illumina Golden Gate assay. Multiple linear regression models were used to determine the association between SNPs and REE. African American carriers of the ‘A’ VDR Cdx2 allele had increased levels of REE in the overall sample and this association was apparent among participants with an adiposity level of <25% and 30% body fat in males and females, respectively. For CASR, an association between carriers of the ‘A’ allele and REE was observed only in those in the upper median of calcium intake. VDR and CASR variants are associated with REE in children, and are influenced by levels of calcium intake and adiposity. Our results bring awareness to mechanisms underlying the regulation of REE and biological and dietary influential factors. PMID:23546818

  19. Resting Energy Expenditure Is Decreased in Pseudohypoparathyroidism Type 1A

    PubMed Central

    Danzig, Jennifer; Groleau, Veronique; McCormack, Shana; Casella, Alex; Harrington, Jennifer; Sochett, Etienne; Tershakovec, Andrew; Zemel, Babette S.; Stallings, Virginia A.; Levine, Michael A.

    2016-01-01

    Context: Pseudohypoparathyroidism type 1A (PHP1A) is caused by loss-of-function mutations on the maternally inherited GNAS allele and is associated with early-onset obesity, neurocognitive defects, and resistance to multiple hormones. The role of energy intake vs central regulation of energy expenditure in the pathophysiology of obesity remains unclear. Objective: The aim of this study was to evaluate resting energy expenditure (REE) in participants with PHP1A. Design: We assessed REE, biochemical, endocrine, and auxological status of 12 participants with PHP1A who had normal or elevated body mass index; controls were a cohort of 156 obese participants. Setting: This study took place at Children's Hospital in Philadelphia and Sick Children's Hospital in Toronto. Main Outcome Measures: REE as a percent of predicted REE was the outcome measure. Results: PHP1A participants had normal endocrine status while receiving appropriate hormone replacement therapy, but had significantly decreased REE as a percent of predicted REE (using the modified Schofield equation). Conclusion: Our results are consistent with REE being the principal cause of obesity in PHP1A rather than it being caused by excessive energy intake or endocrine dysfunction. PMID:26709970

  20. Lanthanide and actinide chemistry at high C/O ratios in the solar nebula

    NASA Technical Reports Server (NTRS)

    Lodders, Katharina; Fegley, Bruce, Jr.

    1993-01-01

    Chemical equilibrium calculations were performed to study the condensation chemistry of the REE and actinides under the highly reducing conditions which are necessary for the formation of the enstatite chondrites. Our calculations confirm that the REE and actinides condensed into oldhamite (CaS), the major REE and actinide host phase in enstatite chondrites, at a carbon-oxygen (C/O) ratio not less than 1 in an otherwise solar gas. Five basic types of REE abundance patterns, several of which are analogous to REE abundance patterns observed in the Ca, Al-rich inclusions in carbonaceous chondrites, are predicted to occur in meteoritic oldhamites. All of the reported REE patterns in oldhamites in enstatite chondrites can be interpreted in terms of our condensation calculations. The observed patterns fall into three of the five predicted categories. The reported Th and U enrichments and ratios in meteoritic oldhamites are also consistent with predictions of the condensation calculations. Pure REE sulfides are predicted to condense in the 10 exp -6 to 10 exp -9 bar range and may be found in enstatite chondrites if they formed in this pressure range.

  1. Effects of citric acid and the siderophore desferrioxamine B (DFO-B) on the mobility of germanium and rare earth elements in soil and uptake in Phalaris arundinacea.

    PubMed

    Wiche, Oliver; Tischler, Dirk; Fauser, Carla; Lodemann, Jana; Heilmeier, Hermann

    2017-02-03

    Effects of citric acid and desferrioxamine B (DFO-B) on the availability of Ge and selected REEs (La, Nd, Gd, Er) to P. arundinacea were investigated. A soil dissolution experiment was conducted to elucidate the effect of citric acid and DFO-B at different concentrations (1 and 10 mmol l(-1) citric acid) on the release of Ge and REEs from soil. In a greenhouse plants of P. arundinacea were cultivated on soil and on sand cultures to investigate the effects of citric acid and DFO-B on the uptake of Ge and REEs by the plants. Addition of 10 mmol l(-1) citric acid significantly enhanced desorption of Ge and REEs from soil and uptake into soil-grown plants. Applying DFO-B enhanced the dissolution and the uptake of REEs, while no effect on Ge was observed. In sand cultures, presence of citric acid and DFO-B significantly decreased the uptake of Ge and REEs, indicating a discrimination of the formed complexes during uptake. This study clearly indicates that citric acid and the microbial siderophore DFO-B may enhance phytoextraction of Ge and REEs due to the formation of soluble complexes that increase the migration of elements in the rhizosphere.

  2. High-resolution and high-sensitivity tephra-inferred fingerprints in stalagmite geochemistry

    NASA Astrophysics Data System (ADS)

    Wu, Chung-Che; Burger, Marcel; Günther, Detlef; Hattendorf, Bodo; Shen, Chuan-Chou

    2016-04-01

    High-resolution and high-sensitivity rare earth elements (REEs) profiles of Holocene stalagmites collected from East Timor (8° 47' S, 126° 23' E) provide detailed fluctuation information which can be inferred to super volcano eruptions. Since REEs are enriched in igneous rocks (~ μg/g) but depleted in carbonates (~ ng/g to pg/g), REEs preserved in stalagmites are acted as an ideal proxy of tephra-inferred signature; however, due to the low REE abundances in most natural stalagmite samples (1-100s ng/g), overall applicability has been sharply limited. Here we develop and apply an improved LA-GED-ICPMS methodology to determine REEs in such low concentration stalagmites. Two pronounced REE peaks occur where their concentrations sharply increased by 1-2 order of magnitudes, from 10s of ng/g to 100s of ng/g. This event was dated at 80 thousand years ago b