Sample records for earth element geochemistry

  1. Rare-earth elements in the Permian Phosphoria Formation: Paleo proxies of ocean geochemistry

    Microsoft Academic Search

    D. Z. Piper; R. B. Perkins; H. D. Rowe

    2007-01-01

    The geochemistry of deposition of the Meade Peak Member of the Phosphoria Formation (MPM) in southeast Idaho, USA, a world-class sedimentary phosphate deposit of Permian age that extends over 300,000km2, is ascertained from its rare earth element (REE) composition. Ratios of REE:Al2O3 suggest two sources—seawater and terrigenous debris. The seawater-derived marine fraction identifies bottom water in the Phosphoria Sea as

  2. Rare-earth elements in the Permian Phosphoria Formation: Paleo proxies of ocean geochemistry

    Microsoft Academic Search

    D. Z. Piper; R. B. Perkins; H. D. Rowe

    2007-01-01

    The geochemistry of deposition of the Meade Peak Member of the Phosphoria Formation (MPM) in southeast Idaho, USA, a world-class sedimentary phosphate deposit of Permian age that extends over 300,000 km2, is ascertained from its rare earth element (REE) composition. Ratios of REE:Al2O3 suggest two sources---seawater and terrigenous debris. The seawater-derived marine fraction identifies bottom water in the Phosphoria Sea

  3. Kiglapait geochemistry VII: Yttrium and the rare earth elements

    NASA Astrophysics Data System (ADS)

    Morse, S. A.; Nolan, K. M.

    1985-07-01

    Based on 51 wholerock analyses by XRF and summation over the layered group, the Kiglapait Intrusion contains 4.7 -1.6+1.2 ppm Y, which resides principally in augite and apatite. Using liquid compositions calculated by summation, the partition coefficient D AUG/LY is 0.95 ± 0.12 from 84 to 97 PCS (percent solidified) and 1.5 ± 0.4 above 97 PCS. For feldspar, the most likely value for D is 0.028 ± 0.02 ( N = 6). REE analyses for 13 whole rocks were interpreted with the aid of yttrium models to yield trends for wholerocks and liquids vs PCS. Summations over the rocks of the layered group gave La = 2.5, Ce = 5.8, Nd = 3.9, Sm = 1.0, Eu = 0.8, Tb = 0.17, Yb = 0.37, and Lu = 0.06 ppm, with 2 s.d. errors near ± 30%. All these elements are highly incompatible until the arrival of augite, which affects chiefly the HREE, and apatite, which affects all (but more strongly, the LREE). The net result is that after apatite arrival at 94 PCS, the liquid compositions are nearly constant, hence D REEWR/L ? 1.0. These results are compatible with the mineralogy of the intrusion and the estimated partition coefficients for feldspar, olivine, augite, apatite, and Fe-Ti oxide minerals. For pre-apatite liquids, D REEFSP/L vary regularly with the normative di content of the liquid and change by an order of magnitude, hence the bulk liquid composition must be considered in any attempt to invert the compositions of feldspars to parent liquids. The Eu anomaly at first decreases in Kiglapait liquids due to plagioclase fractionation, but then increases due to removal of augite and apatite with negative Eu anomalies. The features dominantly responsible for Eu partitioning are liquid structure and, for monoclinic ternary feldspars, crystal structure. The former is best monitored by the augite or diopside content of the liquid and the latter, by the K content of the feldspar. The chondrite-normalized REE pattern for the intrusion has LaN = 7.4, LuN = 1.6, ( Ce/Yb) N = 3.6 , and Eu/Eu? = 2.4 , indicating its feldspar-rich nature. The chilled margin of the nearby Hettasch Intrusion has a similar but more evolved pattern, corresponding roughly to the Kiglapait liquid at 70 PCS. As with other data, those for the REE suggest source differences for the two intrusions rather than a relationship due to fractionation.

  4. Rare earth element geochemistry of hydrothermal deposits from the active TAG Mound, 26°N Mid-Atlantic Ridge

    Microsoft Academic Search

    Rachel A. Mills; Henry Elderfield

    1995-01-01

    The rare earth element (REE) geochemistry of various phases from the active TAG hydrothermal mound has been examined and related to their mineralogy and fluid chemistry. The mound deposits range from black and white smoker chimneys, massive anhydrite\\/sulphide mixtures, oxides, and ochres. All phases, except black smoker chimney anhydrite, demonstrate a positive Eu anomaly when normalised to chondrite REE values.

  5. Produced fluids and shallow groundwater in coalbed methane (CBM) producing regions of Alberta, Canada: Trace element and rare earth element geochemistry

    Microsoft Academic Search

    Katrina Cheung; Hamed Sanei; Patrick Klassen; Bernhard Mayer; Fariborz Goodarzi

    2009-01-01

    The production of coalbed methane (CBM) represents a vital new source of natural gas supply in Western Canada. There are, however, concerns over potential negative environmental impacts on groundwater resources caused by potential contamination with fluids and gases from coal-bearing strata. This paper provides a brief description of the geochemistry and a detailed discussion of trace element and rare earth

  6. Rare earth element geochemistry and petrogenesis of miles (IIE) silicate inclusions

    NASA Astrophysics Data System (ADS)

    Hsu, Weibiao

    2003-12-01

    An ion probe study of rare earth element (REE) geochemistry of silicate inclusions in the Miles IIE iron meteorite was carried out. Individual mineral phases among inclusions have distinct REE patterns and abundances. Most silicate grains have homogeneous REE abundances but show considerable intergrain variations between inclusions. A few pyroxene grains display normal igneous REE zoning. Phosphates (whitlockite and apatite) are highly enriched in REEs (50 to 2000 × CI) with a relatively light rare earth element (LREE)-enriched REE pattern. They usually occurred near the interfaces between inclusions and Fe host. In Miles, albitic glasses exhibit two distinctive REE patterns: a highly fractionated LREE-enriched (CI normalized La/Sm ˜15) pattern with a large positive Eu anomaly and a relatively heavy rare earth element (HREE)-enriched pattern (CI-normalized Lu/Gd ˜4) with a positive Eu anomaly and a negative Yb anomaly. The glass is generally depleted in REEs relative to CI chondrites. The bulk REE abundances for each inclusion, calculated from modal abundances, vary widely, from relatively depleted in REEs (0.1 to 3 × CI) with a fractionated HREE-enriched pattern to highly enriched in REEs (10 to 100 × CI) with a relatively LREE-enriched pattern. The estimated whole rock REE abundances for Miles are at ˜ 10 × CI with a relatively LREE-enriched pattern. This implies that Miles silicates could represent the product of a low degree (˜10%) partial melting of a chondritic source. Phenocrysts of pyroxene in pyroxene-glassy inclusions were not in equilibrium with coexisting albitic glass and they could have crystallized from a parental melt with REEs of ˜ 10 × CI. Albitic glass appears to have formed by remelting of preexisting feldspar + pyroxene + tridymite assemblage. Yb anomaly played an important role in differentiation processes of Miles silicate inclusions; however, its origin remains unsolved. The REE data from this study suggest that Miles, like Colomera and Weekeroo Station, formed when a molten Fe ball collided on a differentiated silicate regolith near the surface of an asteroid. Silicate fragments were mixed with molten Fe by the impact. Heat from molten Fe caused localized melting of feldspar + pyroxene + tridymite assemblage. The inclusions remained isolated from one another during subsequent rapid cooling.

  7. Rethinking early Earth phosphorus geochemistry

    PubMed Central

    Pasek, Matthew A.

    2008-01-01

    Phosphorus is a key biologic element, and a prebiotic pathway leading to its incorporation into biomolecules has been difficult to ascertain. Most potentially prebiotic phosphorylation reactions have relied on orthophosphate as the source of phosphorus. It is suggested here that the geochemistry of phosphorus on the early Earth was instead controlled by reduced oxidation state phosphorus compounds such as phosphite (HPO32?), which are more soluble and reactive than orthophosphates. This reduced oxidation state phosphorus originated from extraterrestrial material that fell during the heavy bombardment period or was produced during impacts, and persisted in the mildly reducing atmosphere. This alternate view of early Earth phosphorus geochemistry provides an unexplored route to the formation of pertinent prebiotic phosphorus compounds, suggests a facile reaction pathway to condensed phosphates, and is consistent with the biochemical usage of reduced oxidation state phosphorus compounds in life today. Possible studies are suggested that may detect reduced oxidation state phosphorus compounds in ancient Archean rocks. PMID:18195373

  8. Aquatic geochemistry of the rare earth elements and yttrium in the Pioneer River catchment, Australia

    Microsoft Academic Search

    Michael G. LawrenceA; Stacy D. JupiterB; Balz S. KamberC

    2006-01-01

    The rare earth elements are strong provenance indicators in geological materials, yet the potential for tracing provinciality in surface freshwater samples has not been adequately tested. Rare earth element and yttrium concentrations were measured at 33 locations in the Pioneer River catchment, Mackay, central Queensland,Australia. The rare earth element patterns were compared on the basis of geological, topographical and land-use

  9. Geochemistry of the Rare Earth elements in spilites from the oceanic and continental crust

    Microsoft Academic Search

    Albert Günter Herrmann; Mark J. Potts; Doris Knake

    1974-01-01

    Analytical data including major elements, the Rare Earths, Ni, Cu, Zn, Rb, and Sr are presented for twenty-three spilites from the Mid-Atlantic Ridge, the Hercynian part of the Variscan geosyncline in Germany, and several localities in Switzerland. Low grade metamorphism (up to approximately 400° C) and spilitization of basaltic rocks apparently do not alter the original Rare Earth element (REE)

  10. 13.21 Geochemistry of the Rare-Earth Element, Nb, Ta, Hf, and Zr Deposits RL Linnen, University of Western Ontario, London, ON, Canada

    E-print Network

    Chakhmouradian, Anton

    13.21 Geochemistry of the Rare-Earth Element, Nb, Ta, Hf, and Zr Deposits RL Linnen, University of rare metals in natural fluids 551 13.21.2.2.2 Aqueous complexation and mineral solubility 552 13 Acknowledgments 564 References 564 13.21.1 Introduction Rare-element mineral deposits, also called rare-metal

  11. Rare-Earth Element Geochemistry of the Samail Ophiolite near Ibra, Oman

    Microsoft Academic Search

    John S. Pallister; Roy J. Knight

    1981-01-01

    Rare-earth element (REE) analyses of 68 rock and mineral separate samples from the Samail ophiolite clearly. differentiate the various units of the ophiolite suite and indicate that the crustal suite is cogenetic, produced by crystal fractionation of basaltic magma in a spreading ridge magma chamber. Mantle peridotires are residual in rare-earth character, but cannot be clearly related to the overlying

  12. Rare earth element geochemistry of upper Ordovician cherts from the Southern Uplands of Scotland

    Microsoft Academic Search

    A. W. OWEN; H. A. ARMSTRONG; J. D. FLOYD

    1999-01-01

    Caradoc and Ashgill radiolarian cherts and siliceous mudstones from the Southern Uplands preserve primary rare earth element (REE) signatures which are comparable to those of more recent deposits from continental margin settings. This is incompatible with the widely held view of these rocks as open ocean deposits incorporated in an accretionary prism and reinforces the model of deposition on an

  13. Time of Formation of Earth and Mars Constrained by Siderophile Element Geochemistry and the Hafnium-182-Tungsten-182 Isotope System

    NASA Astrophysics Data System (ADS)

    Yu, Gang

    182Hf-182W chronometry is considered the most powerful tool to determine the formation timescale of the terrestrial planets. However, previous work employed oversimplified accretion and core formation models. The accretion and core formation models presented here for the 182W isotopic evolution in the mantles of the accreting Earth and Mars, can incorporate the core formation conditions constrained by siderophile element geochemistry and can be successfully applied to constrain the formation timescale of Earth and Mars. Elemental abundance analyses of the Allende meteorite and two martian meteorites lead to new estimates of core-mantle concentration ratios of Si, V, Cr and Mn for Earth and two distinct mantle Hf/W ratios for Mars respectively, and provide better constraints on the models. It is concluded that formation of the proto-Earth (˜87% of its present mass) has to complete rapidly in 10.7 +/- 2.5 Myr after the onset of the Solar System for a late (? 52 Myr) Moon-forming giant impact. The mean time of Mars' accretion is determined to be 3.6 +/- 0.1 Myr, meaning that Mars accretes to 95% of its present mass in 10.8 +/- 0.3 Myr after the formation of the Solar System. Therefore, Mars is not a planetary embryo, and Mars and proto-Earth may be formed on a similar timescale if a late Moon-forming giant impact is assumed. In contrast, if the Moon formed early at ˜30 Myr then it takes about 3 times longer to form the proto-Earth compared to Mars. A stochastic mantle stirring and sampling model was developed to investigate the evolution of W isotope heterogeneities in the mantles of Earth and Mars after accretion and core formation. Our results confirm the mantle stirring rate of ˜ 500 Myr constrained by the long-lived isotope systems in Earth and suggest that the mantle stirring rate in Mars is much slower (˜2 Ga). A new concept is developed: the core formation memory of a siderophile element. Siderophile elements are shown to have different capabilities in recording core formation history, a very important fact to consider in any core formation modeling.

  14. The rare earth element geochemistry of Mono Lake water and the importance of carbonate complexing

    Microsoft Academic Search

    KEVIN H. JOHANNESSON; W. BERRY LYONS

    1994-01-01

    Rare earth element (REE) concentrations for the alkaline, saline waters of Mono Lake in eastern California are reported. The total REE concentrations of the lake water ranged from 4,68 1 to 7,979 pmol kg- I. Shale-normalized REE profiles for the lake water indicate that the heavy REEs (HREE) are enriched 20-200 times over the light REEs (LREE) compared to shale.

  15. 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.

  16. Geochemistry of the rare earth elements in ferromanganese nodules from DOMES Site A, northern equatorial Pacific

    SciTech Connect

    Calvert, S.E.; Piper, D.Z.; Baedecker, P.A.

    1987-09-01

    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 sea water because of the greater degree of complexation of the latter elements with sea water ligands, b) the very efficient oxidative scavenging of Ce on particle surfaces in sea water, 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 in a function of their growth from geochemically evolved AABW. In contrast, the REE chemistry of highland nodules indicates growth from a local, less evolved sea water source.

  17. 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.

  18. Rare earth element geochemistry of hydrothermal deposits from the active TAG Mound, 26{degrees}N mid-Atlantic ridge

    SciTech Connect

    Mills, R.A. [Univ. of Southampton (United Kingdom)] [Univ. of Southampton (United Kingdom); Elderfield, H. [Univ. of Cambridge (United Kingdom)] [Univ. of Cambridge (United Kingdom)

    1995-09-01

    The rare earth element (REE) geochemistry of various phases from the active TAG hydrothermal mound has been examined and related to their mineralogy and fluid chemistry. The mound deposits range from black and white smoker chimneys, massive anhydrite/sulphide mixtures, oxides, and ochres. All phases, except black smoker chimney anhydrite, demonstrate a positive Eu anomaly when normalised to chondrite REE values. REE substitution into sulphide and sulphate phases appears to be strongly influenced by crystallographic control for all REE other than Eu. Precipitation of anhydrite within the TAG mound is the major mechanism for removal of REE during mound circulation and 0.15-0.35 g anhydrite is inferred to precipitate from every kg of fluid venting from the white smoker chimneys. Oxides from the mound fall into three different categories with distinct REE patterns: oxide rims on sulphides, atacamite-bearing oxides, and silica-rich Fe-oxides and ochres. The oxide rim phases contain sulphide and seawater derived REEs whereas the atacamite-bearing oxides and the ochreous material exhibit no seawater signature which suggests precipitation from, or alteration by, a modified hydrothermal fluid.

  19. Rare earth element geochemistry of massive sulfides-sulfates and gossans on the Southern Explorer Ridge

    SciTech Connect

    Barrett, T.J. (McGill Univ., Montreal, Quebec (Canada)); Jarvis, I. (School of Geological Sciences, Surrey (England)); Jarvis, K.E. (Univ. of Surrey, Guildford, Surrey (England))

    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.

  20. The geochemistry of rare earth elements in groundwater from the Carnmenellis area, southwest England

    SciTech Connect

    Smedley, P.L. (British Geological Survey, Wallingford (United Kingdom))

    1991-10-01

    Shallow groundwater samples from the Carnmenellis area of southwest England collected from wells, boreholes, springs, adits and stream baseflow represent recently recharged waters of low salinity. Their major ion concentrations closely reflect the lithology of their host rocks which comprise the Carnmenellis granite and Devonian metasediments (and metabasite) of greenschist grade. Groundwaters from the granite are predominantly Na-Cl or Na-Ca-Cl type while those from the metasediment are Na-Ca-Mg-Cl-HCO{sub 3} waters with a larger range of compositions. The major ion compositions are predominantly a function of water-rock interaction processes and the larger range of metasediment-water compositions probably reflects the greater lithological variation. Rare earth element (REE) concentrations of 0.45 {mu}m-filtered groundwater samples have been determined by inductively coupled plasma mass spectrometry (ICP-MS). A large range of concentrations exists and many are below detection limits but levels reach up to 229 {mu}g/1 (1.6 {mu}m) total REEs. The REEs are strongly controlled by pH with higher levels in groundwaters of pH < 6. In the granite, the REEs are probably derived mainly from the accessory minerals monazite and apatite as well as the high-REE framework minerals biotite and muscovite. The source of REEs in groundwater from the metasediments is more uncertain but probably includes clay minerals, chlorite, and carbonate. The observed REE compositions of granite- and metasediment-derived groundwaters from the Carnmenellis area are so distinctive that the REEs in general and Ce in particular might be useful as future tracers in studies of water-rock interaction and groundwater provenance.

  1. Rare earth element geochemistry in cold-seep pore waters of Hydrate Ridge, northeast Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Himmler, Tobias; Haley, Brian A.; Torres, Marta E.; Klinkhammer, Gary P.; Bohrmann, Gerhard; Peckmann, Jörn

    2013-07-01

    The concentrations of rare earth elements (REEs), sulphate, hydrogen sulphide, total alkalinity, calcium, magnesium and phosphate were measured in shallow (<12 cm below seafloor) pore waters from cold-seep sediments on the northern and southern summits of Hydrate Ridge, offshore Oregon. Downward-decreasing sulphate and coevally increasing sulphide concentrations reveal sulphate reduction as dominant early diagenetic process from ~2 cm depth downwards. A strong increase of total dissolved REE (?REE) concentrations is evident immediately below the sediment-water interface, which can be related to early diagenetic release of REEs into pore water resulting from the re-mineralization of particulate organic matter. The highest pore water ?REE concentrations were measured close to the sediment-water interface at ~2 cm depth. Distinct shale-normalized REE patterns point to particulate organic matter and iron oxides as main REE sources in the upper ~2-cm depth interval. In general, the pore waters have shale-normalized patterns reflecting heavy REE (HREE) enrichment, which suggests preferential complexation of HREEs with carbonate ions. Below ~2 cm depth, a downward decrease in ?REE correlates with a decrease in pore water calcium concentrations. At this depth, the anaerobic oxidation of methane (AOM) coupled to sulphate reduction increases carbonate alkalinity through the production of bicarbonate, which results in the precipitation of carbonate minerals. It seems therefore likely that the REEs and calcium are consumed during vast AOM-induced precipitation of carbonate in shallow Hydrate Ridge sediments. The analysis of pore waters from Hydrate Ridge shed new light on early diagenetic processes at cold seeps, corroborating the great potential of REEs to identify geochemical processes and to constrain environmental conditions.

  2. Investigations of the geochemistry of the rare earth elements in the exogenic cycle

    SciTech Connect

    Olivarez, A.M.

    1989-01-01

    This study investigates the REE geochemistry of three common sediment types (hydrothermal, eolian, and benthic layers) in order to understand their role in the exogenic cycle. The impact of seafloor hydrothermal activity upon the REE content of seawater was investigated by comparing REE/Fe ratios of hydrothermal sediments with end-member plume values. Hydrothermal activity results in a net depletion in REE's from seawater, primarily due to the large scavenging capacity of iron oxyhydroxides which precipitate from these solutions. The discrepancy between the predicted (positive) versus observed (negative) Eu anomaly of seawater was investigated by calculating REE scavenging indices for DSDP Site 598 hydrothermal precipitates is proportional to REE concentration in the fluid phase. The REE content of Lake Superior benthic layers are dominated by lithogenous sources, with minor contributions from the water column. The mechanism of REE removal from the water column may involve scavenging by Fe-rich phases. The eolian dust component of Pacific sediments is derived from two sources: the continental crust and oceanic crust, probably ash from circum-Pacific volcanism. The relative amount of the two end-members influences the median grain size. An eolian flux maximum exists between 35{degree}N and 42{degree}N in the northwest Pacific. This region also receives more eolian materials during glacial versus interglacial stages. A comparison of chemically treated versus untreated loess samples suggests that eolian dust is not a significant source of dissolved REE's to the oceans.

  3. Rare earth element and stable isotope (O, S) geochemistry of barite from the Bijgan deposit, Markazi Province, Iran

    NASA Astrophysics Data System (ADS)

    Ehya, Farhad

    2012-01-01

    The Bijgan barite deposit, which is located northeast of Delijan in Markazi Province of Iran, occurs as a small lenticular body at the uppermost part of an Eocene volcano-sedimentary rock unit. The presence of fossiliferous and carbonaceous strata suggests that the host rocks were deposited in a quiet marine sedimentary environment. Barite, calcite, iron oxides and carbonaceous clay materials are found as massive patches as well as thin layers in the deposit. Barite is marked by very low concentrations of Sr (1-2%) and total amounts of rare earth elements (REEs) (6.25-17.39 ppm). Chondrite-normalized REE patterns of barite indicate a fractionation of light REEs (LREEs) from La to Sm, similar to those for barite of different origins from elsewhere. The LaCN/LuCN ratios and chondrite-normalized REE patterns reveal that barite in the Bijgan deposit is enriched in LREE relative to heavy rare earth elements (HREEs). The similarity between the Ce/La ratios in the barite samples and those found in deep-sea barite supports a marine origin for barite. Lanthanum and Gd exhibit positive anomalies, which are common features of marine chemical sediments. Cerium shows a negative anomaly in most samples that was inherited from the negative Ce anomaly of hydrothermal fluid that mixed with seawater at the time of barite precipitation. The ?18O values of barites show a narrow range of 9.1-11.4‰, which is close to or slightly lower than that of contemporaneous seawater at the end of the Eocene. This suggests a contribution of oxygen from seawater in the barite-forming solution. The ?34S values of barites (9.5-15.3‰) are lower than that of contemporaneous seawater, which suggests a contribution of magmatic sulfur to the ore-forming solution. The oxygen and sulfur isotope ratios indicate that submarine hydrothermal vent fluids are a good analog for solutions that precipitated barite, due to similarities in the isotopic composition of the sulfates. The available data including tectonic setting, host rock characteristics, REE geochemistry, and oxygen and sulfur isotopic compositions support a submarine hydrothermal origin for the Bijgan barite deposit. At the seafloor, barite deposition occurred where ascending Ba-bearing hydrothermal fluids encountered seawater. Sulfate was derived from the sulfate-bearing marine waters, and, to a lesser extent, by oxidized H2S, which was derived from magmatic hydrothermal fluids.

  4. The geochemistry of rare earth elements in the seasonally anoxic water column and porewaters of Chesapeake Bay

    SciTech Connect

    Sholkovitz, E.R.; Shaw, T.J.; Schneider, D.L. (Woods Hole Oceanographic Inst., MA (United States))

    1992-09-01

    A twelve cruise time-series study of a seasonally anoxic basin in Chesapeake Bay was carried out between February 1988 and February 1989. Data from filtered bottom water and upper (0-1 cm) porewater samples are presented. This is the first study in which time-series measurements have been employed to understand the low temperature geochemistry of rare earth elements (REEs). The focus is on the coupling between REDOX (Reduction-Oxidation) variations and REE cycling, fractionation of trivalent REEs and development of cerium anomalies. The time-series results demonstrate that REEs have large seasonal cycles in both the water column and porewaters in response to the development of anoxia in the spring and reoxygenation in the fall. The transition from oxic to suboxic to anoxic conditions results in the release of REEs into the upper porewaters and bottom waters. The release of REEs and Fe are coincident in the bottom waters, while the release of REEs lags Fe by approximately 50 days in the upper porewaters. The release of REEs to the upper porewaters and bottom water are accompanied by (1) fractionation across the trivalent REE series and by (2) the preferential input of Ce relative to its trivalent-only REE neighbors. REE(III) fractionation is such that the relative rate of release increases from Lu to La (light REE > middle REE > heavy REE). During reoxygenation, removal of dissolved REEs occurs from both the water column and upper porewaters and follows the same relative rates, LREE > MREE > HREE. Cerium removal occurs faster than its neighbor REE(III), indicating a rapid oxidation of Ce(III) to Ce(IV).

  5. Earth and Space Sciences Geochemistry 111

    E-print Network

    Henkel, Werner

    Earth and Space Sciences #12;Geochemistry 111 5 Earth and Space Sciences Research in the realm of Earth and Space Sci- ences focusses on the observation and qualitative and quantitative description of natural phenom- ena on Earth and in the Universe, on the detailed study and experimental and computational

  6. Geochemistry of the rare-earth elements in hypersaline and dilute acidic natural terrestrial waters: Complexation behavior and middle rare-earth element enrichments

    Microsoft Academic Search

    Kevin H. Johannesson; W. Berry Lyons; Mary A. Yelken; Henri E. Gaudette; Klaus J. Stetzenbach

    1996-01-01

    Rare-earth element (REE) speciation was modelled in acid (2.9 ? pH ? 3.5), hypersaline groundwaters from Australia and from the Palo Duro Basin in Texas, USA, using a combined specific ion interaction (Pitzer model) and ion pairing model. The free metal ion species (i.e. Ln3+) is the dominant form of dissolved REEs in these systems, accounting for 40–70% of the

  7. Strontium isotopes and rare-earth element geochemistry of hydrothermal carbonate deposits from Lake Tanganyika, East Africa

    NASA Astrophysics Data System (ADS)

    Barrat, J. A.; Boulègue, J.; Tiercelin, J. J.; Lesourd, M.

    2000-01-01

    At Cape Banza (North Tanganyika Lake), fluids and aragonite chimneys have been collected many times since the discovery of this sublacustrine field in 1987. This sampling has been investigated here for the Sr isotopic compositions and the rare-earth element features of the carbonates and a few fluid samples. The 87Sr/ 86Sr ratios of the chimneys indicate that they have precipitated from a mixture of lake water (more than 95%) and hydrothermal fluids. No zoning in the chimneys was detected with our Sr data. For the rare-earth elements, the situation is more complex. The external walls of the chimneys are rare-earth-element-poor (La ? 500 ppb, Yb ? 200 ppb, La/Yb = 2 to 3.4). Their shale normalised rare-earth element patterns suggest that they are in equilibrium with the inferred carbonate-depositing fluids. The rare-earth element concentrations of the internal walls of the chimneys are significantly light rare earth elements (LREE)-enriched with La contents sometimes up to 5 ppm. We suggest that they contain more vent-fluid rare-earth elements than the external wall samples, possibly adsorbed on the surface of growing crystals or simply hosted by impurities. It was not possible to constrain the nature of these phases, but the variations of the compositions of the internal wall materials of the active chimneys with time, as well as data obtained on an inactive chimney indicate that this rare-earth element excess is mobile. Partition coefficients were calculated between the external wall aragonite and carbonate-depositing fluid. The results are strikingly similar to the values obtained by Sholkovitz and Shen (1995) on coral aragonite, and suggest that there is no significant biologic effect on the incorporation of rare-earth elements into coral aragonite and that the various carbonate complexes involved Me(CO 3+) complexes are the main LREE carriers in seawater (Cantrell and Byrne, 1987) instead of Me(CO 3) 2- in Banza fluids) have the same behaviour during aragonite precipitation.

  8. Strontium isotopes and rare-earth element geochemistry of hydrothermal carbonate deposits from Lake Tanganyika, East Africa

    SciTech Connect

    Barrat, J.A.; Boulegue, J.; Tiercelin, J.J.; Lesourd, M.

    2000-01-01

    At Cape Banza (North Tanganyika Lake), fluids and aragonite chimneys have been collected many times since the discovery of this sublacustrine field in 1987. This sampling has been investigated here for the Sr isotopic compositions and the rare-earth element features of the carbonates and a few fluid samples. The {sup 87}Sr/{sup 86}Sr ratios of the chimneys indicate that they have precipitated from a mixture of lake water (more than 95%) and hydrothermal fluids. No zoning in the chimneys was detected with the Sr data. For the rare-earth elements, the situation is more complex. The external walls of the chimneys are rare-earth-element-poor (La {approx} 500 ppb, Yb {approx} 200 ppb, La/Yb = 2 to 3.4). Their shale normalized rare-earth element patterns suggest that they are in equilibrium with the inferred carbonate-depositing fluids. The rare-earth element concentrations of the internal walls of the chimneys are significantly light rare earth elements (LREE)-enriched with La contents sometimes up to 5 ppm. The authors suggest that they contain more vent-fluid rare-earth elements than the external wall samples, possibly adsorbed on the surface of growing crystals or simply hosted by impurities. It was not possible to constrain the nature of these phases, but the variations of the compositions of the internal wall materials of the active chimneys with time, as well as data obtained on an inactive chimney indicate that this rare-earth element excess is mobile. Partition coefficients were calculated between the external wall aragonite and carbonate-depositing fluid. The results are strikingly similar to the values obtained by Sholkovitz and Shen (1995) on coral aragonite, and suggest that there is no significant biologic effect on the incorporation of rare-earth elements into coral aragonite and that the various carbonate complexes involved Me(CO{sub 3}{sup +}) complexes are the main LREE carriers in seawater instead of Me(CO{sub 3}){sub 2}{sup {minus}} in Banza fluids have the same behavior during aragonite precipitation.

  9. Geochemistry of alkaline earth elements (Mg, Ca, Sr, Ba) in the surface sediments of the Yellow Sea

    Microsoft Academic Search

    Guebuem Kim; Han-Soeb Yang; Thomas M. Church

    1999-01-01

    The concentrations of alkaline earth elements were measured in the surface sediments of the Yellow Sea in an attempt to establish their sources from horizontal distributions. The maximum concentrations of Mg are found in the central Yellow Sea, and its horizontal distribution is mainly controlled by quartz dilution. The concentrations of Ca and Sr increase toward the southeastern Yellow Sea

  10. Rare earth element geochemistry of the molybdenum-bearing granitoids in the Jinduicheng-Huanglongpu district, Shaanxi Province, northwest China

    Microsoft Academic Search

    F. J. Nie

    1994-01-01

    Located in the Luonan county, Shaanxi Province, northwest China, Jinduicheng, Shijiawan and Huanglongpu molybdenum deposits constitute the most important molybdenum mineralized district in China. Among these three deposits, the Jinduicheng and Shijiawan molybdenum deposits are connected spatially and genetically with granitoid porphyry (124 ± 6 Ma, K-Ar biotite), and consist of disseminated-veinlet ores. Geochemical studies of rare earth elements (REE)

  11. Rare earth element mineralogy, geochemistry, and preliminary resource assessment of the Khanneshin carbonatite complex, Helmand Province, Afghanistan

    USGS Publications Warehouse

    Tucker, Robert D.; Belkin, Harvey E.; Schulz, Klaus J.; Peters, Stephen G.; Buttleman, Kim P.

    2011-01-01

    There is increased concern about the future availability of rare earth elements (REE) because of China's dominance as the supplier of more than 95 percent of world REE output, their decision to restrict exports of rare earth products, and the rapid increase in world-wide consumption of rare earth product. As a result, countries such as the United States, Japan, and member nations of the European Union face a future of tight supplies and high prices for rare earth products unless other sources of REE are found and developed (Long and others, 2010; U.S. Geological Survey, 2011, p. 128-129, 184-185). We report and describe a significant new deposit of light rare earth elements (LREE), estimated at 1 Mt, within the Khanneshin carbonatite complex of south Afghanistan. The potential resource is located in a remote and rugged part of the igneous complex in a region previously identified by Soviet geologists in the 1970s. This report reviews the geologic setting of LREE deposit, presents new geochemical data documenting the grade of LREE mineralization, briefly describes the mineralogy and mineralogical associations of the deposit, and presents a preliminary estimate of LREE resources based on our current understanding of the geology.

  12. Rare-earth element geochemistry of Colour Lake, an acidic freshwater lake on Axel Heiberg Island, Northwest Territories, Canada

    Microsoft Academic Search

    Kevin H. Johannesson; W. Berry Lyons

    1995-01-01

    A lake column profile was collected in 24 m of water from Colour Lake, Axel Heiberg Island, Northwest Territories, Canada, in early June of 1991 beneath 1.8 m of lake-ice. The rare-earth element (REE) concentrations of the acidic, fresh waters of Colour Lake were analyzed, along with the major solute chemistry, in order to investigate REE distribution and speciation in

  13. Geochemistry and biogeochemistry of rare earth elements in a surface environment (soil and plant) in South China

    Microsoft Academic Search

    Li Miao; Ruisong Xu; Yueliang Ma; Zhaoyu Zhu; Jie Wang; Rui Cai; Yu Chen

    2008-01-01

    Plants and soils derived from different kinds of parent materials in South China were collected for analyses of rare earth\\u000a elements (REEs) by inductively coupled plasma-mass spectrometry (ICP-MS). The distribution patterns and transportation characteristics\\u000a of REEs in the soil–plant system were studied. The results show that geochemical characteristics of REEs depend on the types\\u000a of soils, soils derived from granite

  14. Strontium isotopes and rare-earth element geochemistry of hydrothermal carbonate deposits from Lake Tanganyika, East Africa

    Microsoft Academic Search

    J. A. Barrat; J. Boulègue; J. J. Tiercelin; M. Lesourd

    2000-01-01

    At Cape Banza (North Tanganyika Lake), fluids and aragonite chimneys have been collected many times since the discovery of this sublacustrine field in 1987. This sampling has been investigated here for the Sr isotopic compositions and the rare-earth element features of the carbonates and a few fluid samples. The 87Sr\\/86Sr ratios of the chimneys indicate that they have precipitated from

  15. Geochemistry and biogeochemistry of rare earth elements in a surface environment (soil and plant) in South China

    NASA Astrophysics Data System (ADS)

    Miao, Li; Xu, Ruisong; Ma, Yueliang; Zhu, Zhaoyu; Wang, Jie; Cai, Rui; Chen, Yu

    2008-11-01

    Plants and soils derived from different kinds of parent materials in South China were collected for analyses of rare earth elements (REEs) by inductively coupled plasma-mass spectrometry (ICP-MS). The distribution patterns and transportation characteristics of REEs in the soil-plant system were studied. The results show that geochemical characteristics of REEs depend on the types of soils, soils derived from granite being the highest in REE concentration. In a soil profile, REE concentrations are higher in B and C horizons than those in A horizon, with Eu negative anomaly and Ce positive anomaly. Plants of different genera growing in the same sampling site have quite similar REE distribution pattern, but plants of the same genera growing in different soils show considerable variation in characteristics of REEs. The patterns of the different parts of plant resemble each other, but the slope of the patterns becomes different. REEs have fractionated when they were transported and migrated from soil to plant root, stem and leaf, revealing that heavy REEs are relatively less available. REEs distributions in plants are influenced by the soil they grow in and also characterized by their individual biogeochemical characteristics. Biological absorption coefficients indicate difference of REE absorption capacity of plants.

  16. Rare earth element geochemistry of the molybdenum-bearing granitoids in the Jinduicheng-Huanglongpu district, Shaanxi Province, northwest China

    NASA Astrophysics Data System (ADS)

    Nie, F. J.

    1994-12-01

    Located in the Luonan county, Shaanxi Province, northwest China, Jinduicheng, Shijiawan and Huanglongpu molybdenum deposits constitute the most important molybdenum mineralized district in China. Among these three deposits, the Jinduicheng and Shijiawan molybdenum deposits are connected spatially and genetically with granitoid porphyry (124 ± 6 Ma, K-Ar biotite), and consist of disseminated-veinlet ores. Geochemical studies of rare earth elements (REE) furnish further evidence for understanding the rock- and ore-forming processes of these two porphyry molybdenum deposits and their related granitoid rocks. The REE distribution in molybdenum ore, granitoids and their Middle Proterozoic meta-volcanic wall rocks is discussed. The similarities between the REE signatures of the Shijiawan molybdenum-bearing monzogranite porphyry and the neighbouring Laoneushan monzogranite (130 ± 5 Ma, K-Ar biotite) show that they were produced at the same evolutional stage of granitoid magma derived mainly from crustal anatexis. The Shijiawan biotite monzogranite porphyry may be an apophysis of the Laoneushan granitoid batholith. Compared to the Shijiawan monzogranite porphyry, the Jinduicheng molybdenum-bearing granite porphyry is characterized by a high content of HREE, and depletion in LREE. The unique REE patterns indicates that the molybdenum-bearing granite porphyry was formed by thermogravitation diffusion of a granitoid magma. The slight depletion of REE abundance in the altered granitoid porphyry and meta-volcanic wall rocks shows that leaching of REE occurred during breakdown of the primary mineral assemblage, and crystallization of secondary minerals. The high REE content of molybdenum ore represented re-deposition of the mobilized molybdenum and REE.

  17. Rare earth element geochemistry of groundwaters from a thick till and clay-rich aquitard sequence, Saskatchewan, Canada

    SciTech Connect

    Johannesson, K.H.; Hendry, M.J.

    2000-05-01

    Owing to their exceptionally low hydraulic conductivities and extensive a real distribution, clay-rich deposits are of interest because of their potential as repository sites for the disposal of high-level radioactive wastes and heavy metals, as well as their use as protective covers for regional aquifer systems. Consequently, understanding the geochemical processes controlling solutes, such as transuranics and other heavy metals, in clay-rich deposits is of particular concern in order to properly assess the suitability of these deposits as potential waste repository sites. Rare earth elements (REE) were determined in groundwater samples collected from a thick till and clay-rich aquitard sequence located in southern Saskatchewan, Canada. The groundwaters are Na-Mg-SO{sub 4}-type waters that range from highly concentrated brines near the ground surface to relatively dilute waters at depth. The majority of these groundwaters have pH values between 7 and 8, although the deepest samples are more alkaline. Groundwater REE concentrations are relatively constant in the overlying till but increase by up to a factor of 50 in the underlying clay bedrock. Shallow groundwaters have heavy REE (HREE)--enriched shale-normalized patterns, whereas the REE patterns of the deep groundwaters are relatively flat. Solution complexation modeling indicates that variations in REE patterns reflect differences in solution complexation across the REE suite. In the shallow groundwaters, strongly adsorbed, positively charged carbonate complexes, sulfate complexes and free metal ion species dominate the speciation of light REEs (LREE), whereas HREEs occur chiefly as more stable, negatively charged dicarbonato complexes. For the deepest groundwaters, however, all of the REEs are predicted to occur in solution as dicarbonato complexes. The large HREE enrichments of the shallow groundwaters reflect the greater affinity of the positively charged LREE solution species to adsorb to clay minerals or coatings on clay minerals in the aquitard sequence compared to the more stable, negatively charged HREE dicarbonato complexes. On the other hand, the flat REE patterns, of the deep groundwaters reflect the dominance of the negatively charged dicarbonato complex for all REEs. The solution complexation model along with the strong positive correlation between REEs and to a lesser extend pH, indicates that carbonate ion concentrations, and thus pH, exert important controls on aqueous REE concentrations in these groundwaters.

  18. Early depositional history of metalliferous sediments in the Atlantis II Deep of the Red Sea: Evidence from rare earth element geochemistry

    NASA Astrophysics Data System (ADS)

    Laurila, Tea E.; Hannington, Mark D.; Petersen, Sven; Garbe-Schönberg, Dieter

    2014-02-01

    The Atlantis II Deep is a brine-filled depression on the slowly spreading Red Sea rift axis. It is by far the largest deposit of hydrothermally precipitated metals on the present ocean floor and the only known modern deposit that is analogous to laminated Fe-rich chemical sediments, such as banded iron formation (BIF). The brine pool at the bottom of the Atlantis II Deep creates an environment where most of the hydrothermally sourced elements can be dispersed and deposited over an area of ˜60 km2. We analyzed the rare earth element concentrations in 100 small-volume samples from 9 cores in different parts of the Atlantis II Deep to better understand the origins of different types of metalliferous sediments (detrital, proximal hydrothermal and distal hydrothermal). Our results agree with earlier studies based on larger bulk samples that show the composition of the major depositional units is related to major changes in the location and intensity of hydrothermal activity and the amount of hydrothermal versus background sedimentation. In this paper, we address the origins of chemically distinct laminae (down to sub-millimeter) that correspond to ˜annual deposition. REE patterns clearly reflect 3 different sources (e.g., detrital, scavenging, direct hydrothermal input). Detrital REE that are delivered to the Deep from outside account for most of the REE in the sediments of the Atlantis II Deep, similar to BIF, and are unaffected by fractionation due to hydrothermal processes during deposition and diagenesis. Fe- and Mn-(oxy)hydroxides that form at the anoxic-oxic boundary scavenge REE from the brine pool as they settle. The Fe-(oxy)hydroxides contain a larger proportion of REE from seawater than any other sediment-type and also scavenge REE from pore waters after deposition. In contrast, the Mn-(oxy)hydroxides dissolve before deposition and thus function as transporting agents between seawater and the brine. However, there is little evidence for direct seawater influence in the REE geochemistry of the sediments (e.g., Y/Ho ratio). Non-ferrous sulfides form proximal to the hydrothermal vent source and inherit an hydrothermal REE pattern. The total REE content of the presently forming Fe-(oxy)hydroxides is very low due to limited input of REE into the brine. The largest proportion of non-detrital REE appears to have been deposited early in the history of the basin from an initial brine pool that was relatively enriched in REE, followed by a change in REE chemistry in later sediments. Similar abrupt changes in the REE chemistry of ancient chemical sediments may record similar processes, including changes in local basin evolution and input of REE from different sources.

  19. Geochemistry.

    ERIC Educational Resources Information Center

    Fyfe, William S.

    1979-01-01

    Techniques in geochemistry continue to improve in sensitivity and scope. The exciting areas of geochemistry still include the classical fields of the origin of the elements and objects in space, but environmental crisis problems are important as well. (Author/BB)

  20. The Medical Geochemistry of Dusts, Soils, and Other Earth Materials

    NASA Astrophysics Data System (ADS)

    Plumlee, G. S.; Ziegler, T. L.

    2003-12-01

    "Town clenched in suffocating grip of asbestos"USA Today, article on Libby,Montana, February, 2000"Researchers find volcanoes are bad for your health… long after they finish erupting"University of WarwickPress Release, 1999"Toxic soils plague city - arsenic, lead in 5 neighborhoods could imperil 17,000 residents"Denver Post, 2002"Ill winds - dust storms ferry toxic agents between countries and even continents"Science News, 2002A quick scan of newspapers, television, science magazines, or the internet on any given day has a fairly high likelihood of encountering a story (usually accompanied by a creative headline such as those above) regarding human health concerns linked to dusts, soils, or other earth materials. Many such concerns have been recognized and studied for decades, but new concerns arise regularly.Earth scientists have played significant roles in helping the medical community understand some important links between earth materials and human health, such as the role of asbestos mineralogy in disease (Skinner et al., 1988; Ross, 1999; Holland and Smith, 2001), and the role of dusts generated by the 1994 Northridge, California, earthquake in an outbreak of Valley Fever ( Jibson et al., 1998; Schneider et al., 1997).Earth science activities tied to health issues are growing (Skinner and Berger, 2003), and are commonly classified under the emerging discipline of medical geology (Finkelman et al., 2001; Selinus and Frank, 2000; Selinus, in press).Medical geochemistry (also referred to as environmental geochemistry and health: Smith and Huyck (1999), Appleton et al. (1996)) can be considered as a diverse subdiscipline of medical geology that deals with human and animal health in the context of the Earth's geochemical cycle ( Figure 1). Many medical geochemistry studies have focused on how chemical elements in rocks, soils, and sediments are transmitted via water or vegetation into the food chain, and how regional geochemical variations can result in disease clusters either through dietary deficiency of essential elements or dietary excess of toxic elements. (28K)Figure 1. Potential human exposure routes within the earth's geochemical cycle can come from a wide variety of both natural and anthropogenic sources. This chapter focuses on a somewhat narrower area of medical geochemistry: the study of mechanisms of uptake of earth materials by humans and animals and their reactions to these materials. In order for earth materials to affect health, they must first interact with the body across key interfaces such as the respiratory tract, gastrointestinal tract, skin, and eyes. In some way, all of these interfaces require the earth materials to interact chemically with water-based body fluids such as lung fluids, gastrointestinal fluids, saliva, or blood plasma.The primary goal of this chapter, co-authored by a geochemist and a toxicologist, is to provide both geochemists and scientists from health disciplines with an overview of the potential geochemical mechanisms by which earth materials can influence human health. It is clear that significant opportunities for advancement in this arena will require continued and increased research collaborations between geochemists and their counterparts in the health disciplines.

  1. Geochemistry (Isotopic Geochemistry) Trace element variations in an archeological carbonate deposit

    E-print Network

    Paris-Sud XI, Université de

    Geochemistry (Isotopic Geochemistry) Trace element variations in an archeological carbonate deposit that trace elements analysis in archaeological carbonates have the potential to provide high- resolution ablation ICP-MS analyses are performed along the growth axis of an archaeological carbonate deposit from

  2. 12.479 Trace-Element Geochemistry, Fall 2006

    E-print Network

    Frey, Frederick August

    Focuses on element distribution in rocks and minerals using data obtained from natural and experimental systems. Emphasizes models describing trace-element partitioning and applications of trace-element geochemistry to ...

  3. Trace element geochemistry of Archean volcanic rocks

    NASA Technical Reports Server (NTRS)

    Jahn, B.-M.; Shih, C.-Y.; Murthy, V. R.

    1974-01-01

    The K, Rb, Sr, Ba and rare-earth-element contents of some Archean volcanic rocks from the Vermilion greenstone belt, northeast Minnesota, were determined by the isotopic dilution method. The characteristics of trace element abundances, supported by the field occurrences and major element chemistry, suggest that these volcanic rocks were formed in an ancient island arc system.

  4. Trace and rare-earth element geochemistry in tourmaline and cassiterite from the Yunlong tin deposit, Yunnan, China: implication for migmatitic–hydrothermal fluid evolution and ore genesis

    Microsoft Academic Search

    Shao-Yong Jiang; Ji-Min Yu; Jian-Jun Lu

    2004-01-01

    Yunlong tin deposit is a medial-sized hydrothermal deposit in western Yunnan province of China. This deposit is unusual because the tin mineralization occurs exclusively within the migmatite bodies. The genesis of the ore deposit has been hotly debated and various models have been proposed including granite-related magmatic–hydrothermal and migmatitic–hydrothermal origins. This paper reports a systematic trace and rare-earth elements (REE)

  5. Insights into Igneous Geochemistry from Trace Element Partitioning

    NASA Technical Reports Server (NTRS)

    Jones, J. H.; Hanson, B. Z.

    2001-01-01

    Partitioning of trivalent elements into olivine are used to explore basic issues relevant to igneous geochemistry, such as Henry's law. Additional information is contained in the original extended abstract.

  6. 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. [Bristol Univ. (United Kingdom)] [Bristol Univ. (United Kingdom); Sturchio, N.C. [Argonne National Lab., IL (United States)] [Argonne National Lab., IL (United States)

    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.

  7. Fluid inclusion, rare earth element geochemistry, and isotopic characteristics of the eastern ore zone of the Baiyangping polymetallic Ore district, northwestern Yunnan Province, China

    NASA Astrophysics Data System (ADS)

    Feng, Caixia; Bi, Xianwu; Liu, Shen; Hu, Ruizhong

    2014-05-01

    The Baiyangping Cu-Ag polymetallic ore district is located in the northern part of the Lanping-Simao foreland fold belt, which lies between the Jinshajiang-Ailaoshan and Lancangjiang faults in western Yunnan Province, China. The source of ore-forming fluids and materials within the eastern ore zone were investigated using fluid inclusion, rare earth element (REE), and isotopic (C, O, and S) analyses undertaken on sulfides, gangue minerals, wall rocks, and ores formed during the hydrothermal stage of mineralization. These analyses indicate: (1) The presence of five types of fluid inclusion, which contain various combinations of liquid (l) and vapor (v) phases at room temperature: (a) H2O (l), (b) H2O (l) + H2O (v), (c) H2O (v), (d) CmHn (v), and (e) H2O (l) + CO2 (l), sometimes with CO2 (v). These inclusions have salinities of 1.4-19.9 wt.% NaCl equivalents, with two modes at approximately 5-10 and 16-21 wt.% NaCl equivalent, and homogenization temperatures between 101 °C and 295 °C. Five components were identified in fluid inclusions using Raman microspectrometry: H2O, dolomite, calcite, CH4, and N2. (2) Calcite, dolomitized limestone, and dolomite contain total REE concentrations of 3.10-38.93 ppm, whereas wall rocks and ores contain REE concentrations of 1.21-196 ppm. Dolomitized limestone, dolomite, wall rock, and ore samples have similar chondrite-normalized REE patterns, with ores in the Huachangshan, Xiaquwu, and Dongzhiyan ore blocks having large negative ?Ce and ?Eu anomalies, which may be indicative of a change in redox conditions during fluid ascent, migration, and/or cooling. (3) ?34S values for sphalerite, galena, pyrite, and tetrahedrite sulfide samples range from -7.3‰ to 2.1‰, a wide range that indicates multiple sulfur sources. The basin contains numerous sources of S, and deriving S from a mixture of these sources could have yielded these near-zero values, either by mixing of S from different sources, or by changes in the geological conditions of seawater sulfate reduction to sulfur. (4) The C-O isotopic analyses yield ?13C values from ca. zero to -10‰, and a wider range of ?18O values from ca. +6 to +24‰, suggestive of mixing between mantle-derived magma and marine carbonate sources during the evolution of ore-forming fluids, although potential contributions from organic carbon and basinal brine sources should also be considered. These data indicate that ore-forming fluids were derived from a mixture of organism, basinal brine, and mantle-derived magma sources, and as such, the eastern ore zone of the Baiyangping polymetallic ore deposit should be classified as a “Lanping-type” ore deposit.

  8. Ecotoxicity of rare earth elements Rare earth elements (REEs) or rare earth metals is the

    E-print Network

    Wehrli, Bernhard

    Ecotoxicity of rare earth elements Info Sheet Rare earth elements (REEs) or rare earth metals isolated. Actually, most rare earth elements exist in the Earth's crust in higher concentrations than though most people have never heard of rare earth elements, sev- eral of them govern mankind's modern

  9. Trace element geochemistry of CR chondrite metal

    E-print Network

    Jacquet, Emmanuel; Alard, Olivier; Kearsley, Anton T; Gounelle, Matthieu

    2015-01-01

    We report trace element analyses by laser ablation inductively coupled plasma mass spectrometry of metal grains from 9 different CR chondrites, distinguishing grains from chondrule interior ("interior grains"), chondrule surficial shells ("margin grains") and the matrix ("isolated grains"). Save for a few anomalous grains, Ni-normalized trace element patterns are similar for all three petrographical settings, with largely unfractionated refractory siderophile elements and depleted volatile Au, Cu, Ag, S. All types of grains are interpreted to derive from a common precursor approximated by the least melted, fine-grained objects in CR chondrites. This also excludes recondensation of metal vapor as the origin of the bulk of margin grains. The metal precursors presumably formed by incomplete condensation, with evidence for high-temperature isolation of refractory platinum-group-element (PGE)-rich condensates before mixing with lower temperature PGE-depleted condensates. The rounded shape of the Ni-rich, interior ...

  10. Rare Earth Elements in Soils

    Microsoft Academic Search

    Zhengyi Hu; Silvia Haneklaus; Gerd Sparovek; Ewald Schnug

    2006-01-01

    Rare earth elements (REEs) comprise a group of 17 elements with very similar chemical and physical properties, which include scandium (Sc, Z=21), yttrium (Y, Z=39), and the lanthanides with successive atomic numbers (Z from 57 to 71). Lanthanides are the elements lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium

  11. DALHOUSIE UNIVERSITY, DEPARTMENT OF EARTH SCIENCES Assistant Professor -Geophysics, Sedimentology, or Geochemistry

    E-print Network

    Brownstone, Rob

    DALHOUSIE UNIVERSITY, DEPARTMENT OF EARTH SCIENCES Assistant Professor - Geophysics, Sedimentology, or Geochemistry The Department of Earth Sciences at Dalhousie University invites applications for a faculty research projects. Essential qualifications include a Ph.D. in Earth Sciences or closely related field

  12. Trace element geochemistry of magmatic rock series of converging and diverging plate boundaries

    Microsoft Academic Search

    M. Treuil; J. L. Joron; H. Jaffrezic

    1977-01-01

    The new results and developments of trace element geochemistry of magmatic processes are discussed. The interest and limits\\u000a of neutron activation analysis for studies of trace element distributions in magnetic rocks are shown.

  13. Pourret Olivier, Gruau Grard, Dia Aline, Davranche Mlanie, and Molnat Jrome. (2010) Colloidal control on the distribution of rare earth elements in shallow

    E-print Network

    Paris-Sud XI, Université de

    2010-01-01

    control on the distribution of rare earth elements in shallow groundwaters. Aquatic Geochemistry 16 (1 OF RARE EARTH ELEMENTS IN SHALLOW GROUNDWATERS Olivier Pourret1, 2, § , Gérard Gruau1,* , Aline Dia1;3 Abstract A 7-year monitoring period of rare earth element (REE) concentrations and REE pattern shapes

  14. Minor element zoning and trace element geochemistry of pallasites

    NASA Astrophysics Data System (ADS)

    Hsu, W.

    2003-08-01

    I report here on an ion probe study of minor element spatial distributions and trace element concentrations in six pallasites. Pallasite olivines exhibit ubiquitous minor element zoning that is independent of grain size, morphology, and adjacent phases. Ca, Cr, Ti, V, and Ni concentrations decrease from center to rim by factors of up to 10, while Mn is generally unzoned or increases slightly at the very edge of some olivine grains. The maximum concentrations of these elements at the center of olivine vary from grain to grain within the same meteorite and among the pallasites studied. These zoning profiles are consistent with thermal diffusion during rapid cooling. The inferred cooling rates at high temperature regimes are orders of magnitude faster than the low-temperature metallographic cooling rates (~0.5 to 2 deg C/Ma). This suggests that pallasites, like mesosiderites, have experienced rather complicated thermal histories, i.e., cooling rapidly at high temperatures and slowly at low temperatures. Pallasite olivines are essentially free of REEs. However, the phosphates display a wide range of REE abundances (0.001 to 100 x CI) with distinct patterns. REEs are generally homogeneous within a given grain but vary significantly from grain to grain by a factor of up to 100. Albin and Imilac whitlockite are highly enriched in HREEs (~50 x CI) but are relatively depleted in LREEs (~0.1 to 1 x CI). Eagle Station whitlockite has a very unusual REE pattern: flat LREEs at a 0.1 x CI level, a large positive Eu anomaly, and a sharp increase from Gd (0.1 x CI) to Lu (70 x CI). Eagle Station stanfieldite has a similar REE pattern to that of whitlockite but with much lower REEs by a factor of 10 to 100. Springwater farringtonite has relatively low REE concentrations (0.001 to 1 x CI) with a highly fractionated HREE-enriched pattern (CI-normalized Lu/La ~100). Postulating any igneous processes that could have fractionated REEs in these phosphates is difficult. Possibly, phosphates were incorporated into pallasites during mixing of olivine and IIIAB-like molten Fe. These phosphates preserve characteristics of a previous history. Pallasites have not necessarily formed at the mantle-core boundary of their parent bodies. The pallasite thermal histories suggest that pallasites may have formed at a shallow depth and were subsequently buried deep under a regolith blanket.

  15. Rare earth element partitioning between hydrous ferric oxides and acid mine water during iron oxidation

    Microsoft Academic Search

    Philip L. Verplanck; D. Kirk Nordstrom; Howard E. Taylor; Briant A. Kimball

    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

  16. Nicolas F. Spycher Staff Geological Scientist Earth Sciences Division, Geochemistry Department ph. 510 495-2388

    E-print Network

    Ajo-Franklin, Jonathan

    Nicolas F. Spycher Staff Geological Scientist Earth Sciences Division, Geochemistry Department ph of Oregon Research and Professional Experience 1998-present Staff Geological Scientist, Lawrence Berkeley transport under non-isothermal multiphase flow conditions, Computers & Geosciences 37, 763­774. Spycher, N

  17. Rare earth elements: end use and recyclability

    USGS Publications Warehouse

    Goonan, Thomas G.

    2011-01-01

    Rare earth elements are used in mature markets (such as catalysts, glassmaking, lighting, and metallurgy), which account for 59 percent of the total worldwide consumption of rare earth elements, and in newer, high-growth markets (such as battery alloys, ceramics, and permanent magnets), which account for 41 percent of the total worldwide consumption of rare earth elements. In mature market segments, lanthanum and cerium constitute about 80 percent of rare earth elements used, and in new market segments, dysprosium, neodymium, and praseodymium account for about 85 percent of rare earth elements used. Regardless of the end use, rare earth elements are not recycled in large quantities, but could be if recycling became mandated or very high prices of rare earth elements made recycling feasible.

  18. Core-Mantle Partitioning of Volatile Elements and the Origin of Volatile Elements in Earth and Moon

    NASA Technical Reports Server (NTRS)

    Righter, K.; Pando, K.; Danielson, L.; Nickodem, K.

    2014-01-01

    Depletions of siderophile elements in mantles have placed constraints on the conditions on core segregation and differentiation in bodies such as Earth, Earth's Moon, Mars, and asteroid 4 Vesta. Among the siderophile elements there are a sub-set that are also volatile (volatile siderophile elements or VSE; Ga, Ge, In, As, Sb, Sn, Bi, Zn, Cu, Cd), and thus can help to constrain the origin of volatile elements in these bodies, and in particular the Earth and Moon. One of the fundamental observations of the geochemistry of the Moon is the overall depletion of volatile elements relative to the Earth, but a satisfactory explanation has remained elusive. Hypotheses for Earth include addition during accretion and core formation and mobilized into the metallic core, multiple stage origin, or addition after the core formed. Any explanation for volatile elements in the Earth's mantle must also be linked to an explanation of these elements in the lunar mantle. New metal-silicate partitioning data will be applied to the origin of volatile elements in both the Earth and Moon, and will evaluate theories for exogenous versus endogenous origin of volatile elements.

  19. The geochemistry of carbonatites revisited: Two major types of continental carbonatites and their trace-element signatures

    NASA Astrophysics Data System (ADS)

    Chakhmouradian, A.

    2009-04-01

    There have been several attempts to systematize the geochemistry of carbonatites, most recently by Samoilov (1984), Nelson et al. (1988), Woolley and Kempe (1989), and Rass (1998). These studies revealed a number of important geochemical characteristics that can be used to track the evolutionary history of these rocks, distinguish them from modally similar metamorphic parageneses, and aid in mineral exploration for rare earths, niobium and other resources commonly associated with carbonatites. Important breakthroughs in the understanding of carbonatite petrogenesis and numerous reports of new carbonatite localities made in the past two decades lay the ground for a critical re-assessment of the geochemistry of these rocks. A new representative database of whole-rock carbonatite analyses was compiled from the post-1988 literature and various unpublished sources. The database contains 820 analyses encompassing calcio-, magnesio- and ferrocarbonatites from 174 localities (ca. one-third of the total number of carbonatites known worldwide) reduced to ca. 350 analyses following the approach of Woolley and Kempe (1989). Carbonatites emplaced in oceanic settings (e.g., Cape Verde), ophiolite belts (e.g., Oman), or those of uncertain tectonic affinity (e.g., El Picacho in Mexico) were not included. Two major types of continental carbonatites can be distinguished on the basis of their geological setting and trace-element geochemistry: (1) carbonatites emplaced in rifts and smaller-scale extensional structures developed in stable Archean cratons or paleo-orogenic belts, and (2) carbonatites emplaced in collisional settings following the orogenesis. In both settings, the most common and best-studied type of carbonatite is calcite carbonatite (predominantly intrusive with a small percentage of extrusive occurrences), which accounts for 62% of the analyses included in the database. Both types of carbonatite are typically associated with alkaline silicate lithologies (meleigites, nepheline syenites, etc.), but those associated with type-1 rocks are typically Na-rich and silica-undersaturated, whereas type-2 carbonatites are associated with K-rich silica-saturated to undersaturated syenites. Type-1 carbonatites are notably different from their type-2 counterparts in showing higher abundances of high-field-strength elements (HFSE = Ti, Zr, Hf, Nb, Ta), Rb, U and V, but lower levels of Sr, Ba, Pb, rare-earth elements, F and S. Key element ratios are also different in the two carbonatite types; in particular, Rb/K, Nb/Ta, Zr/Hf and Ga/Al values are consistently higher in type-1 samples. Notably, some element ratios (e.g., Co/Ni and Y/Ho) are very similar in both groups. Type-2 carbonatites commonly show a 13C-depleted signature relative to the "primary carbonatite" range (Deines, 1989). The observed differences in geological setting and geochemistry indicate the existence of two distinct carbonatite sources in the subcontinental lithosphere: amphibole-bearing lherzolite producing type-1 rocks (cf. Chakhmouradian, 2006), and subducted oceanic crust (rutile-bearing eclogite?) yielding type-2 melts depleted in HFSE, but enriched in light carbon, large-ion-incompatible elements, F and S. References: Chakhmouradian, A.R. (2006) High-field-strength elements in carbonatitic rocks: Geochemistry, crystal chemistry and significance for constraining the sources of carbonatites. Chem. Geol., 235, 138-160. Deines, P. (1989) Stable isotope variations in carbonatites. In: Carbonatites: Genesis and Evolution (K. Bell, Ed.). Unwin Hyman, London, 301-359. Nelson, D.R., Chivas, A.R., Chappell, B.V. and McCulloch, M.T. (1988) Geochemical and isotopic systematic in carbonatites and implications for the evolution of ocean-island sources. Geochim. Cosmochim. Acta, 52, 1-17. Rass, I.T. (1998) Geochemical features of carbonatite indicative of the composition, evolution, and differentiation of their mantle magmas. Geochem. Int., 36, 107-116. Samoilov, V.S. (1984) Geochemistry of Carbonatites. Nauka, Moscow (in Russ.). Woolley, A.R. and Kempe, D.R.C. (1989)

  20. Rare Earth Element Mines, Deposits, and Occurrences

    E-print Network

    Torgersen, Christian

    Rare Earth Element Mines, Deposits, and Occurrences by Greta J. Orris1 and Richard I. Grauch2 Open Table 1. Rare earth mineral codes and associated mineral names.......................................................................................6 Table 2. Non-rare earth mineral codes and associated mineral names

  1. Trace element geochemistry of the Whitewood Mine coals in Alberta

    SciTech Connect

    Gentzis, T. [Alberta Research Council, Edmonton, Alberta (Canada). Resource Technologies Div.; Goodarzi, F. [Geological Survey of Canada, Calgary, Alberta (Canada). Inst. of Sedimentary and Petroleum Geology; Hickinbotham, A. [TransAlta Utilities Corp., Calgary, Alberta (Canada)

    1996-06-01

    Subbituminous coals, taken from a freshly mined open pit as well as from nine drillholes in the Whitewood Mine, Alberta, were analyzed for their elemental and radionuclide concentration. Furthermore, the coal ash was analyzed for major oxides, and a comparison was made with coals of similar rank and present only 12 km away, in the Highvale Mine. The Whitewood Mine coals are clean by world standards and do not contain any environmentally deleterious elements in excess amounts. They are suitable for utilization, but care should be taken to minimize the negative opacity effects on the electrostatic precipitators (ESPs). The low Na{sub 2}O content in the coals, particularly in the open-pit samples, may affect ash resistivity. This could result in a decrease in the flow of current and thus a decrease in the precipitator efficiency. Certain trends of major oxides in the coal ash are observed in a north-south direction and are discussed, with particular emphasis on the Na{sub 2}O distribution in the six coal seams. The Whitewood Mine drillhole samples contain the following mean concentration of elements in ppm, unless stated otherwise: As (4.7), Br (15.1), Cl (21.5), Co (3.3), Cr (7), Mo (4.8), Na (710), Ca (1.5%), Mn (110), Th (6), U (2.5), V (19.3), and Sb (0.7). In the surface samples, the mean concentrations of the above elements are as follows in ppm: As (4.5), Br (196.2), Cl (38.4), Co (5.4), Cr (200), Mo (16.7), Na (263), Ca (1.4%), Mn (120), Th (5.2), U (1.6), V (14.3), and Sb (0.7). The open-pit surface samples are much enriched in Br, Mo, and Cr, slightly enriched in Cl and Co, much depleted in Na, and slightly depleted in Th, U, and V compared to the drillhole samples. Both sets have similar concentrations of As and Mn. There is a slight increase in As concentration in the north and south ends of the pit; a slight increase in a northern direction was also noted for Si, U, and Na. All rare earth elements are within the world range for most coals.

  2. Overview of Rare Earth Element Investigations in Acid Waters of U. S. Geological Survey Abandoned Mine Lands Watersheds

    Microsoft Academic Search

    Philip L. Verplanck; D. Kirk Nordstrom; Howard E. Taylor

    The geochemistry of rare earth element (REE) variations in acid waters is being studied as part of the U. S. Geological Survey Abandoned Mine Lands Initiative in two pilot watersheds, upper Animas, Colorado and Boulder, Montana. The following objectives are under investigation: (1) comparison of acid mine waters and naturally acidic springs, (2) determination of whether the dominant control on

  3. Determination of rare earth elements in black shales by inductively coupled plasma mass spectrometry

    Microsoft Academic Search

    E. V Smirnova; I. N Fedorova; G. P Sandimirova; L. L Petrov; N. G Balbekina; V. I Lozhkin

    2003-01-01

    We report on the specific occurrence of rare-earth elements (REE) in carbonaceous black shales as determined by inductively coupled plasma mass spectrometry (ICP-MS). Black shales are categorized according to their formation: (i) biogenic (samples SCHS-1 and SLg-1 certified at the Institute of Geochemistry SB RAS); and (ii) bituminous (USGS standard reference samples SDO-1 and SGR-1). Comparison of ICP-MS results obtained

  4. Archean granulite gneisses from eastern Hebei Province, China: rare earth geochemistry and tectonic implications

    Microsoft Academic Search

    Bor-Ming Jahn; Zong-Qing Zhang

    1984-01-01

    The granulite gneisses and their retrograded products of the Qianxi Group from eastern Hebei Province, China, have been investigated for their isotope and trace element geochemistry. A consistent age of about 2.5 AE has been obtained by the Rb-Sr and Sm-Nd whole-rock isochron methods, in agreement with the zircon U-Pb data (Pidgeon 1980; D.Y. Liu, unpubl.). Geochemical arguments from initial

  5. Mineral resource of the month: rare earth elements

    USGS Publications Warehouse

    U.S. Geological Survey

    2011-01-01

    The article provides information on rare earth elements, which are group of 17 natural metallic elements. The rare earth elements are scandium, yttrium and lanthanides and classified into light rare earth elements (LREE) and heavy rate earth elements (HREE). The principal ores of the rare earth elements are identified. An overview of China's production of 97 percent of the rare earths in the world is provided. Commercial applications of rare earths are described.

  6. Toward a unified science of the Earth's surface: Opportunities for synthesis among hydrology, geomorphology, geochemistry, and ecology

    Microsoft Academic Search

    Chris Paola; Efi Foufoula-Georgiou; William E. Dietrich; Miki Hondzo; David Mohrig; Gary Parker; Mary E. Power; Ignacio Rodriguez-Iturbe; Vaughan Voller; Peter Wilcock

    2006-01-01

    The Earth's surface is shaped by the interaction of tectonics, water, sediment, solutes, and biota over a wide range of spatial and temporal scales and across diverse environments. Development of a predictive science of Earth surface dynamics integrates many disciplines and approaches, including hydrology, geomorphology, ocean and atmospheric science, sedimentary and structural geology, geochemistry, and ecology. This paper discusses challenges,

  7. Rare Earth Element Mines, Deposits, and Occurrences

    USGS Publications Warehouse

    Orris, Greta J.; Grauch, Richard I.

    2002-01-01

    Data on rare earth (including yttrium) mines, deposits, and occurrences were compiled as part of an effort by the USGS and the University of Arizona Center for Mineral Resources to summarize current knowledge on the supply and demand outlook and related topics for this group of elements. Economic competition and environmental concerns are increasingly constraining the mining and processing of rare earths from the Mountain Pass mine in California. For many years, the deposit at Mountain Pass was the world's dominant source of rare earth elements and the United States was essentially self-sufficient. Starting approximately 10 years ago, the U.S. has become increasingly dependent (> 90 percent of separated rare earths) upon imports from China, now the dominant source of rare earths. A knowledge of the known economic and noneconomic sources of rare earths is basic to evaluating the outlook for rare earth supply and associated issues.

  8. Rare earth geochemistry of the Troodos ophiolite complex

    Microsoft Academic Search

    R. W. Kay; R. G. Senechal

    1976-01-01

    new chemical analyses of rocks from the Troodos ophiolite complex offer no clear evidence that it is a piece of oceanic crust. Ratios of selected nonlabile elements (REE, Zr, Ti) in Troodos lavas clearly distinguish them from the calc-alkaline lavas of evolved island arcs and the oceanic island basalts of Hawaiian and Icelandic type. However, these ratios are equivocal in

  9. The rare earth elements in seawater

    Microsoft Academic Search

    Henry Elderfield; Mervyn J. Greaves

    1982-01-01

    The depth distributions of La, Ce, Nd, Sm, Eu, Gd, Dy, Er and Yb in the oceanic water column are used to evaluate the marine geochemical cycle of the rare earth elements and their application as water-mass tracers.

  10. Rare-Earth and Transuranic Elements

    Microsoft Academic Search

    M. Goeppert Mayer

    1941-01-01

    The possible existence of a second rare-earth-like group of elements beginning with uranium and extending to the transuranic elements, is discussed by a calculation of the atomic eigen-functions of the 4f and 5f electrons. Energy and spatial extension of the 4f eigenfunctions drop suddenly at the beginning of the rare-earth group; the binding energy is calculated to be 0.95 ev

  11. Trace element geochemistry of marine biogenic particulate matter

    SciTech Connect

    Collier, R.W.

    1981-02-01

    Plankton samples were investigated for physical and chemical leaching decomposition to identify the major and trace element composition of particulate carrier phases. The identification of trace element/major element ratios in the biogenic materials was emphasized. The majority of the trace elements in the samples were directly associated with the nonskeletal organic phases of the plankton. Calcium carbonate and opal were not significant carriers for any of the trace elements studied. A refractory phase containing Al and Fe in terrigenous ratios was present in all samples, even from the more remote marine locations.

  12. Trace element geochemistry in the upper Amazon drainage basin (Bolivia)

    Microsoft Academic Search

    Françoise Elbaz-Poulichet; Patrick Seyler; Laurence Maurice-Bourgoin; Jean-Loup Guyot; Claude Dupuy

    1999-01-01

    The distribution of trace elements (Sr, Mo, Ba, Rb, U, Mn, Ni, Cu, Zn, and Cd) was investigated in surface waters and associated particulates in two upper Amazonian basins (Mamore and Beni). Dissolved Sr, Ba, Mo, Rb, U and to a lesser extent Zn and Cd correlate with major ions and appear to be predominantly derived from soluble rocks (carbonates,

  13. The major and minor element geochemistry of Lake Baikal

    Microsoft Academic Search

    KELLY KENISON FALKNER; CHRIS I. MEASURES; SARAH E. HERBELIN; JOHN M. EDMOND; RAY F. WEISS

    1991-01-01

    A comprehensive, joint Soviet-American study of the chemistry of Lake Baikal, the world's deepest (1,632 m) lake, was carried out in July 1988. In this paper, we report the major, minor, and preliminary trace element concentrations for three profiles obtained at or near the deepest and central part of the three major basins of the lake. With the exception of

  14. The Role of the Ion Microprobe in Solid-Earth Geochemistry

    NASA Astrophysics Data System (ADS)

    Hauri, E. H.

    2002-12-01

    Despite the early success of the electron microprobe in taking petrology to the micron scale, and the widespread use of mass spectrometers in geochemistry and geochronology, it was not until the mid-1970s that the ion microprobe came into its own as an in situ analytical tool in the Earth sciences. Despite this inauspicious beginning, secondary ion mass spectrometry (SIMS) was widely advertised as a technology that would eventually eclipse thermal ion mass spectrometry (TIMS) in isotope geology. However this was not to happen. While various technical issues in SIMS such as interferences and matrix effects became increasingly clear, an appreciation grew for the complimentary abilities of SIMS and TIMS that, even with the advent of ICP-MS, continues to this day. Today the ion microprobe is capable of abundance measurements in the parts-per-billion range across nearly the entire periodic table, and SIMS stable isotope data quality is now routinely crossing the 1 per mil threshold, all at the micron scale. Much of this success is due to the existence of multi-user community facilities for SIMS research, and the substantial efforts of interested scientists to understand the fundamentals of sputtered ion formation and their application to geochemistry. Recent discoveries of evidence for the existence of ancient crust and oceans, the emergence of life on Earth, the large-scale cycling of surficial materials into the deep Earth, and illumination of fundamental high-pressure phenomena have all been made possible by SIMS, and these (and many more) discoveries owe a debt to the vision of creating and supporting multi-user community facilities for SIMS. The ion microprobe remains an expensive instrument to purchase and maintain, yet it is also exceedingly diverse in application. Major improvements in SIMS, indeed in all mass spectrometry, are visible on the near horizon. Yet the geochemical community cannot depend on commercial manufacturers alone to design and build the next generation of instrumentation for geochemistry. Such will be the role of instrument-minded scientists asking questions that simply cannot be answered by extant means. And it will be multi-user facilities that will make such advancements available to the wider geochemical community.

  15. Light element geochemistry of the Apollo 12 site

    NASA Technical Reports Server (NTRS)

    Kerridge, J. F.; Kaplan, I. R.; Kung, C. C.; Winter, D. A.; Friedman, D. L.; Desmarais, D. J.

    1978-01-01

    Analytical techniques of improved sensitivity have revealed details of the concentrations and isotopic compositions of light elements for a comprehensive suite of samples from the Apollo 12 regolith. These samples show a wide spread in maturity, although maximum contents observed for solar wind elements are less than observed at other sites, possibly reflecting relative recency of craters at the Apollo 12 site. Isotopic composition of nitrogen is consistent with the idea that N-15/N-14 in the solar wind has increased with time, at least a major part of this increase having occurred in the past 3.1 Gyr. Sulfur isotope systematics support a model in which sulfur is both added to the regolith, by meteoritic influx, and lost, by an isotopically selective process. Most soils from this site are heavily contaminated with terrestrial carbon.

  16. Rare earth element scavenging in seawater

    NASA Astrophysics Data System (ADS)

    Byrne, Robert H.; Kim, Ki-Hyun

    1990-10-01

    Examinations of rare earth element (REE) adsorption in seawater, using a variety of surface-types, indicated that, for most surfaces, light rare earth elements (LREEs) are preferentially adsorbed compared to the heavy rare earths (HREEs). Exceptions to this behavior were observed only for silica phases (glass surfaces, acid-cleaned diatomaceous earth, and synthetic SiO 2). The affinity of the rare earths for surfaces can be strongly affected by thin organic coatings. Glass surfaces which acquired an organic coating through immersion in Tampa Bay exhibited adsorptive behavior typical of organic-rich, rather than glass, surfaces. Models of rare earth distributions between seawater and carboxylate-rich surfaces indicate that scavenging processes which involve such surfaces should exhibit a strong dependence on pH and carbonate complexation. Scavenging models involving carboxylate surfaces produce relative REE abundance patterns in good general agreement with observed shale-normalized REE abundances in seawater. Scavenging by carboxylate-rich surfaces should produce HREE enrichments in seawater relative to the LREEs and may produce enrichments of lanthanum relative to its immediate trivalent neighbors. Due to the origin of distribution coefficients as a difference between REE solution complexation (which increases strongly with atomic number) and surface complexation (which apparently also increases with atomic number) the relative solution abundance patterns of the REEs produced by scavenging reactions can be quite complex.

  17. Geochemistry and Light Element Systematics of Moorea, Society Islands

    NASA Astrophysics Data System (ADS)

    Harden, J. A.; Ryan, J. G.; Savov, I. P.

    2002-05-01

    Moorea is the third youngest island in the the Society Islands, a "hotspot" volcanic island chain with EM isotopic affinities. Samples of fresh volcanic rocks from Moorea were collected for chemical characterization and B,Li, and Be analysis, for comparison to other Society island lavas, and to the existing light element database for ocean island basalts (OIBs). The analyzed Moorea samples include primitive and evolved alkali basalts, hawaiites, mugearites, and benmoreites. Olivine and pyroxene phenocrysts are abundant in the most primitive samples, while plagioclase is the dominant phenocryst phase in more evolved samples. SiO2 in our suite ranges from 46% to 58% wt. TiO2 contents increase steadily with decreasing MgO contents (up to 5% wt MgO); in the most evolved rocks (benmoreites and mugearites), TiO2 < 1.5%, and declines with decreasing MgO. Lithium abundances in the lavas vary from 2.9 - 13.2 ppm, and beryllium contents from 1.0 - 3.0 ppm. Both elements increase with progressive differentiation in the suite. Boron abundances range from 1.0 - 3.2 ppm; excluding samples associated with zeolites, the range in B abundances is even narrower (1.0 - 2.4 ppm B). B/K2O and B/Be ratios for basaltic Moorea lavas vary from 0.7-1.4 and 0.6-1.3, respectively, while more evolved samples range to somwhat higher values. These ratios are similar to those for other Society Island lavas, and are lower than those for St. Helena, Erebus, Hawaii, Marquesas, Gough and Reunion, as well as for any analyzed MORB. Our Moorea dataset for basalts confirms earlier survey results from the Societies, and are consistent with a mantle source that includes B-poor subducted materials. The various OIB isotopic "endmembers" (HIMU, EMI, EMII) are not readily resolved by boron abundance ratios.

  18. Rare earth element scavenging in seawater

    SciTech Connect

    Byrne, R.H.; Kim, Kihyun (Univ. of South Florida, St. Petersburg (USA))

    1990-10-01

    Examinations of rare earth element (REE) adsorption in seawater, using a variety of surface-types, indicated that, for most surfaces, light rare earth elements (LREEs) are preferentially adsorbed compared to the heavy rare earths (HREEs). Exceptions to this behavior were observed only for silica phases. The affinity of the rare earths for surfaces can be strongly affected by thin organic coatings. Glass surfaces which acquired an organic coating through immersion in Tampa Bay exhibited adsorptive behavior typical of organic-rich, rather than glass, surfaces. Models of rare earth distributions between seawater and carboxylate-rich surfaces indicate that scavenging processes which involve such surfaces should exhibit a strong dependence on pH and carbonate complexation. Scavenging models involving carboxylate surfaces produce relative REE abundance patterns in good general agreement with observed shale-normalized REE abundances in seawater. Scavenging by carboxylate-rich surfaces should produce HREE enrichments in seawater relative to the LREEs and may produce enrichments of lanthanum relative to its immediate trivalent neighbors. Due to the origin of distribution coefficients as a difference between REE solution complexation and surface complexation the relative solution abundance patterns of the REEs produced by scavenging reactions can be quite complex.

  19. Rare Earth Element Contents of High pCO 2 Groundwaters of Primorye, Russia: Mineral Stability and Complexation Controls

    Microsoft Academic Search

    Paul Shand; Karen H. Johannesson; Oleg Chudaev; Valentina Chudaeva; W. Mike Edmunds

    The rare earth element (REE) geochemistry of cold, high pCO2 groundwaters was studied in springs and boreholes in the Primorye region of the Russian Far East. The gas phase in these\\u000a waters is dominated by mantle-derived CO2 (up to 2.6 atm.), being introduced to shallow groundwaters along major fault systems. The aggressive nature of these moderately\\u000a acidic groundwaters has led

  20. [In Situ Analysis of Element Geochemistry in Submarine Basalt in Hydrothermal Areas from Ultraslow Spreading Southwest Indian Ridge].

    PubMed

    Wang, Yan; Sun, Xiao-ming; Xu, Li; Liang, Ye-heng; Wu, Zhong-wei; Fu, Yu; Huang, Yi

    2015-03-01

    In this study, we analyze element geochemistry of submarine basalt in situ, which is sampled in hydrothermal areas from ultraslow spreading Southwest Indian Ridge, including the fresh basalt rocks (B19-9, B15-13) and altered basalt (B5-2). And we can confirm that altered mineral in B5-2 is celadonite by microscope and Raman Spectrum. Furthermore, amygdaloidal celadonites are analyzed by electron microprobe (EPMA) and EDS-line scanning. The results show that K-contents decrease and Na-contents increase from the core to the edge in these altered minerals, indicating the transition from celadonite to saponite. Celadonite is an altered minerals, forming in low temperature (< 50 degrees C) and oxidizing condition, while saponite form in low water/rock and more reducing condition. As a result, the transition from celadonite to saponite suggests environment change from oxidizing to reducing condition. Using the result of EPMA as internal standard, we can analyze rare earth elements (REE) in altered mineral in situ. Most of result show positive Eu anomaly (?(Eu)), indicating hydrothermal fluid transform from oxidizing to reducing, and reducing fluid rework on the early altered minerals. Comparison with REE in matrix feldspar both in altered and unaltered zoning, we find that reducing fluid can leach REE from the matrix feldspar, leading to lower total REE concentrations and positive Eu anomaly. So leaching process play an important role in hydrothermal system. PMID:26117900

  1. Rare earth elements in alpine peridotites

    Microsoft Academic Search

    M. Loubet; N. Shimizu; C. J. Allègre

    1975-01-01

    The samples from alpine peridotite massifs (Beni Bouchera, Lherz and the Alps) have been analyzed for rare earth elements. The peridotites as a whole are characterized by various degrees of light REE depletion (Ce varies from 1.2 to 0.02 times chondrite) and a small variation in heavy REE (Yb varies about a factor of 2, from 1.3 to 2.2 times

  2. Rare earth element systematics in hydrothermal fluids

    Microsoft Academic Search

    Annie Michard

    1989-01-01

    Rare earth element concentrations have been measured in hydrothermal solutions from geothermal fields in Italy, Dominica, Valles Caldera, Salton Sea and the Mid-Atlantic Ridge. The measured abundances show that hydrothermal activity is not expected to affect the REE balance of either continental or oceanic rocks. The REE enrichment of the solutions increases when the pH decreases. High-temperature solutions (>230°C) percolating

  3. Note: Portable rare-earth element analyzer using pyroelectric crystal

    SciTech Connect

    Imashuku, Susumu, E-mail: imashuku.susumu.2m@kyoto-u.ac.jp; Fuyuno, Naoto; Hanasaki, Kohei; Kawai, Jun [Department of Materials Science and Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan)] [Department of Materials Science and Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan)

    2013-12-15

    We report a portable rare-earth element analyzer with a palm-top size chamber including the electron source of a pyroelectric crystal and the sample stage utilizing cathodoluminescence (CL) phenomenon. The portable rare-earth element analyzer utilizing CL phenomenon is the smallest reported so far. The portable rare-earth element analyzer detected the rare-earth elements Dy, Tb, Er, and Sm of ppm order in zircon, which were not detected by scanning electron microscopy-energy dispersive X-ray spectroscopy analysis. We also performed an elemental mapping of rare-earth elements by capturing a CL image using CCD camera.

  4. Note: Portable rare-earth element analyzer using pyroelectric crystal.

    PubMed

    Imashuku, Susumu; Fuyuno, Naoto; Hanasaki, Kohei; Kawai, Jun

    2013-12-01

    We report a portable rare-earth element analyzer with a palm-top size chamber including the electron source of a pyroelectric crystal and the sample stage utilizing cathodoluminescence (CL) phenomenon. The portable rare-earth element analyzer utilizing CL phenomenon is the smallest reported so far. The portable rare-earth element analyzer detected the rare-earth elements Dy, Tb, Er, and Sm of ppm order in zircon, which were not detected by scanning electron microscopy-energy dispersive X-ray spectroscopy analysis. We also performed an elemental mapping of rare-earth elements by capturing a CL image using CCD camera. PMID:24387481

  5. [Geochemical characteristics of rare earth elements on sunflower growing area in the west of Jilin Province].

    PubMed

    Li, Shu-Jie; Dou, Sen; Wang, Li-Min; Liu, Zhao-Shun

    2011-07-01

    Soil and plant samples were collected from the sunflower growing area in the west of Jilin province. A variety of ancillary methods were used to determine the soil element content. Then the rare earth elements geochemistry in soil was studied, and the correlation of REEs in this region with other elements and the quality of plant was investigated. The results show that, (1) REE content of the soil in Nong'an is relatively higher to those in Daan and Tongyu. Distribution pattern of rare earth elements in soil for the right tilt of the light rare earth enrichment patterns which is consistent with the national distribution pattern of rare earth elements; (2) REE contents in the three studying areas in the soil are different, and this primarily relates to the soil parent materials; (3) The REEs which positively correlate with soil available potassium are Se, Fe2O3, Ti, P, Mn, Cu, Zn, Cr, Mo, B, F. The protein content of sunflower seeds has a negative correlation with REE. With the exception of Lu, all REEs show a similar correlation. PMID:21922834

  6. Normalized rare earth elements in water, sediments, and wine: identifying sources and environmental redox conditions

    USGS Publications Warehouse

    Piper, David Z.; Bau, Michael

    2013-01-01

    The concentrations of the rare earth elements (REE) in surface waters and sediments, when normalized on an element-by-element basis to one of several rock standards and plotted versus atomic number, yield curves that reveal their partitioning between different sediment fractions and the sources of those fractions, for example, between terrestrial-derived lithogenous debris and seawater-derived biogenous detritus and hydrogenous metal oxides. The REE of ancient sediments support their partitioning into these same fractions and further contribute to the identification of the redox geochemistry of the sea water in which the sediments accumulated. The normalized curves of the REE that have been examined in several South American wine varietals can be interpreted to reflect the lithology of the bedrock on which the vines may have been grown, suggesting limited fractionation during soil development.

  7. Catalog of Mount St. Helens 2004 - 2005 Tephra Samples with Major- and Trace-Element Geochemistry

    USGS Publications Warehouse

    Rowe, Michael C.; Thornber, Carl R.; Gooding, Daniel J.; Pallister, John S.

    2008-01-01

    This open-file report presents a catalog of information about 135 ash samples along with geochemical analyses of bulk ash, glass and individual mineral grains from tephra deposited as a result of volcanic activity at Mount St. Helens, Washington, from October 1, 2004 until August 15, 2005. This data, in conjunction with that in a companion report on 2004?2007 Mount St. Helens dome samples by Thornber and others (2008a) are presented in support of the contents of the U.S. Geological Survey Professional Paper 1750 (Sherrod and others, ed., 2008). Readers are referred to appropriate chapters in USGS Professional Paper 1750 for detailed narratives of eruptive activity during this time period and for interpretations of sample characteristics and geochemical data presented here. All ash samples reported herein are currently archived at the David A. Johnston Cascades Volcano Observatory in Vancouver, Washington. The Mount St. Helens 2004?2005 Tephra Sample Catalogue along with bulk, glass and mineral geochemistry are tabulated in 6 worksheets of the accompanying Microsoft Excel file, of2008-1131.xls. Samples in all tables are organized by collection date. Table 1 is a detailed catalog of sample information for tephra deposited downwind of Mount St. Helens between October 1, 2004 and August 18, 2005. Table 2 provides major- and trace-element analyses of 8 bulk tephra samples collected throughout that interval. Major-element compositions of 82 groundmass glass fragments, 420 feldspar grains, and 213 mafic (clinopyroxene, amphibole, hypersthene, and olivine) mineral grains from 12 ash samples collected between October 1, 2004 and March 8, 2005 are presented in tables 3 through 5. In addition, trace-element abundances of 198 feldspars from 11 ash samples (same samples as major-element analyses) are provided in table 6. Additional mineral and bulk ash analyses from 2004 and 2005 ash samples are published in chapters 30 (oxide thermometry; Pallister and others, 2008), 32 (amphibole major elements; Thornber and others, 2008b) and 37 (210Pb; 210Pb/226Pa; Reagan and others, 2008) of U.S. Geological Survey Professional Paper 1750 (Sherrod and others, 2008). A brief overview of sample collection methods is given below as an aid to deciphering the tephra sample catalog. This is followed by an explanation of the categories of sample information (column headers) in table 1. A summary of the analytical methods used to obtain the geochemical data in this report introduces the presentation of major- and trace-element geochemistry of Mount St. Helens 2004?2005 tephra samples in tables 2?6. Rhyolite glass standard analyses are reported (Appendix 1) to demonstrate the accuracy and precision of similar glass analyses presented herein.

  8. Siderophile elements and the earth's formation

    NASA Technical Reports Server (NTRS)

    Jones, J. H.; Capobianco, C. J.; Drake, M. J.; O'Neill, Hugh

    1992-01-01

    Two comments on a work by Murthy (1991) concerning the abundances of siderophile elements in the earth's mantle are presented. In the first comment it is asserted that the basis of Murthy's extrapolation is the assumption that the Gibbs free energy change for the partitioning reaction is independent of temperature, and as this is generally not a valid assumption thermodynamically, and as this is contradicted by most experimental data, the issue of mantle siderophile elements remains unresolved. In the second comment it is asserted that the extrapolation method used by Murthy does not appear to be valid thermodynamically, and that an extrapolation based on generally accepted thermodynamic assumptions yields different results. In a reply, Murthy takes issue with the comments.

  9. Tipping elements in the Earth's climate system

    PubMed Central

    Lenton, Timothy M.; Held, Hermann; Kriegler, Elmar; Hall, Jim W.; Lucht, Wolfgang; Rahmstorf, Stefan; Schellnhuber, Hans Joachim

    2008-01-01

    The term “tipping point” commonly refers to a critical threshold at which a tiny perturbation can qualitatively alter the state or development of a system. Here we introduce the term “tipping element” to describe large-scale components of the Earth system that may pass a tipping point. We critically evaluate potential policy-relevant tipping elements in the climate system under anthropogenic forcing, drawing on the pertinent literature and a recent international workshop to compile a short list, and we assess where their tipping points lie. An expert elicitation is used to help rank their sensitivity to global warming and the uncertainty about the underlying physical mechanisms. Then we explain how, in principle, early warning systems could be established to detect the proximity of some tipping points. PMID:18258748

  10. Rare earth element abundances and distribution patterns in plant materials

    Microsoft Academic Search

    S. B. Aidid

    1994-01-01

    Eight out of the fourteen rare earth elements were estimated from the leaves ofPelthophorum pterocarpum, the leaves and roots ofImpatiens balsamina, and the soils from four sampling sites by instrumental neutron activation analysis. The chondrite normalized rare earth element abundances and distribution patterns in the plant materials were found to be significantly correlated to the abundances of the rare earth

  11. EXTRACTION OF RARE-EARTH ELEMENTS FROM BASTNAESITE CONCENTRATE

    Microsoft Academic Search

    Shaw

    1959-01-01

    Bastnaesite is a natural rare-earth fluorcarbonate of the cerium group ; that affords an abundant and highgrade source of the lighter rare-earth elements. ; A simple and efficient method has been developed by the Bureau of Mines for ; extracting rare-earth compounds from this mineral. Digesting of a flotation ; concentrate with sulfuric acid converts the rare-earth compounds firm ;

  12. Paragneiss zircon geochronology and trace element geochemistry, North Qaidam HP/UHP terrane, western China

    USGS Publications Warehouse

    Mattinson, C.G.; Wooden, J.L.; Zhang, J.X.; Bird, D.K.

    2009-01-01

    In the southeastern part of the North Qaidam terrane, near Dulan, paragneiss hosts minor peridotite and UHP eclogite. Zircon geochronology and trace element geochemistry of three paragneiss samples (located within a ???3 km transect) indicates that eclogite-facies metamorphism resulted in variable degrees of zircon growth and recrystallization in the three samples. Inherited zircon core age groups at 1.8 and 2.5 Ga suggest that the protoliths of these rocks may have received sediments from the Yangtze or North China cratons. Mineral inclusions, depletion in HREE, and absence of negative Eu anomalies indicate that zircon U-Pb ages of 431 ?? 5 Ma and 426 ?? 4 Ma reflect eclogite-facies zircon growth in two of the samples. Ti-in-zircon thermometry results are tightly grouped at ???660 and ???600 ??C, respectively. Inclusions of metamorphic minerals, scarcity of inherited cores, and lack of isotopic or trace element inheritance demonstrate that significant new metamorphic zircon growth must have occurred. In contrast, zircon in the third sample is dominated by inherited grains, and rims show isotopic and trace element inheritance, suggesting solid-state recrystallization of detrital zircon with only minor new growth. ?? 2009 Elsevier Ltd.

  13. Accumulation of rare earth elements in maize plants ( Zea mays L.) after application of mixtures of rare earth elements and lanthanum

    Microsoft Academic Search

    Xingkai Xu; Wangzhao Zhu; Zijian Wang; Geert-Jan Witkamp

    2003-01-01

    Rare earth elements are applied in China to improve crop production, and the distribution patterns of individual rare earth elements in native plants have widely been reported. But our knowledge is still limited about the dose-dependent accumulation of individual rare earth elements in agricultural crops after application of rare earth elements. Effects of lanthanum and mixtures of rare earth elements

  14. 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).

  15. Trace and minor element geochemistry of the rhyolitic volcanic rocks, Central North Island, New Zealand

    Microsoft Academic Search

    A. Ewart; S. R. Taylor; Annette C. Capp

    1968-01-01

    Analytical data are presented for the following elements: Cs, Rb, Ba, K, Sr, Ca, Na, Fe, Mg, Cu, Co, Ni, Li, Sc, V, Cr, Ga, Al, Si, La, Y, and Zr. Eight samples were analysed by the spark source method for rare earths, Tl, Pb, Hf, Sn, Nb, Mo, Bi, and In. In addition to data on rhyolitic volcanics, a

  16. Chondrule trace element geochemistry at the mineral scale Emmanuel JACQUET1*

    E-print Network

    Demouchy, Sylvie

    . Results are similar in all three meteorites. Mesostasis has rare earth element (REE) concentrations of 10­20 · CI. Low-Ca pyroxene has light REE (LREE) concentrations near 0.1 · CI and heavy REE (HREE) near 1. The coarsest olivine crystals tend to have the most fractionated REE patterns, indicative of equilibrium

  17. 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 Marcellus shale brines and in high TDS brines in general. From synthesis of available brine and geological data, we have developed hypotheses about REE occurrence and content of these hypersaline solutions. It is well documented that the REE concentrations of a solution can serve as a signature of the water and changes in this signature represent interactions with fluids of different compositions or changing mineral strata. We will discuss how the unique signatures and reactivity of REE potentially makes these elements uniquely capable tracers of hydrogeologic activity.

  18. Rare earths and other trace elements in Luna 16 soil.

    NASA Technical Reports Server (NTRS)

    Helmke, P. A.; Haskin, L. A.

    1972-01-01

    An analysis has been made of four small samples of material brought to earth by the Luna 16 mission, with the aim to determine rare earths and other trace elements in these samples. The analytical results are tabulated, and the rare earth abundances are compared with the average for chondrites. A comparison is also made with the results of similar analyses of Apollo samples.

  19. DETERMINATION OF RARE EARTH ELEMENTS IN URANIUM COMPOUNDS

    Microsoft Academic Search

    T. Nakazima; M. Takahashi; H. Kawaguchi

    1958-01-01

    A method has been developed for the determination of rare earth elements ; including yttrium in uranium and its compounds. The greater portion of the ; uranium is separated from the rare earths by ether extraction. The rare earths ; are then precipitated as fluorides and subsequently purified as hydroxides. ; Lanthanum was used as the carrier. The efficiency of

  20. EARTH'S CORE FORMATION: NEW CONSTRAINTS FROM SIDEROPHILE ELEMENTS PARTITIONING (Invited)

    Microsoft Academic Search

    J. Siebert; A. Corgne; F. J. Ryerson

    2009-01-01

    The abundances of siderophile elements in the Earth's mantle are the result of core formation in the early Earth. Many variables are involved in the prediction of metal\\/silicate siderophile partition coefficients during core segregation: pressure, temperature, oxygen fugacity, silicate and metal compositions. Despite publications of numerous results of metal-silicate experiments, the experimental database and predictive expressions for elements partitioning are

  1. Peculiarities of rare-earth-element distribution in environmental objects

    Microsoft Academic Search

    A. V. Gorbunov; T. L. Onischenko; S. F. Gundorina; M. V. Frontasyeva

    1993-01-01

    The effect of the production of phosphorus fertilizers on the pollution of the environment by rare-earth elements is reviewed. The main sources of rare-earth element pollution in the environment are described. The levels of REEs in components of the environment — atmosphere, snow, different types of soil, native and agricultural types of vegetation — that provide evidence for their participation

  2. Action of Slow Neutrons on Rare Earth Elements

    Microsoft Academic Search

    G. Hevesy; Hilde Levi

    1936-01-01

    IN view of the discrepancy between the values obtained by different workers for the periods and the intensity of radiation emitted by the radio rare earth elements1-5 after neutron bombardment, we carried out a detailed investigation on this subject and also on the absorption of slow neutrons in rare earth elements. The latter measurements were carried out chiefly to ascertain

  3. Hydrogen-absorbing characteristics of 15 rare earth elements

    Microsoft Academic Search

    K. Hirano; J. Kadono; S. Yamamoto; T. Tanabe; H. Miyake

    2006-01-01

    The amounts of absorbed hydrogen and the rates of hydrogen-absorption reaction were measured for 15 rare earth elements. The cohesive energy and energy fluctuation of metal clusters were also calculated by using the extended-Hückel method. The characteristics of each rare earth element in the capacity of hydrogen absorption and the reaction rate were discussed by comparing the experimental results with

  4. Light elements in the Earth's outer core: A critical review

    Microsoft Academic Search

    Jean-Paul Poirier

    1994-01-01

    There is little doubt that densities for the Earth's outer core, inferred from seismology, require that it is constituted of an alloy of liquid iron and light elements. However, the nature of the light alloying elements is still uncertain as it depends in a large measure on the conditions of accretion of the Earth and formation of the core. The

  5. [Content of rare earth elements in wild Hypericum japonicum Thunb].

    PubMed

    Wei, Zhen-Lin; Rui, Yu-Kui; Tian, Zhi-Huan

    2009-06-01

    Rare earth elements are important nutritional elements for human health, and today more and more attention has been paid to the effective components in Chinese traditional medicine, especially to rare earth elements. Fifteen rare earth elements in wild hypericum japonicum Thunb were analyzed by the methods of ICP-MS. The results showed that the concentrations of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Tm, Lu and Y ranged from 6 ng x g(-1) x DW to 14 522 ng x g(-1) x DW, and among them the concentrations of La, Ce and Nd were higher than 2 000 ng x g(-1) x DW. Compared with the concentration of rare earth elements in rice, corn, wheat and barley, the total concentration of rare earth elements in hypericum japonicum Thunb was much higher, which could be the mechanism of curative effect of hypericum japonicum Thunb on liverish diseases. The character of elements and the content of rare earth elements in soil should be responsible for the difference, but the distributive mechanism of rare earth elements in hypericum japonicum Thunb should be further studied. PMID:19810563

  6. Peculiarities in the Behavior of Rare-Earth Elements in Their Determination in Black Shales by Inductively Coupled Plasma Mass Spectrometry

    Microsoft Academic Search

    E. V. Smirnova; I. N. Fedorova; G. P. Sandimirova; L. L. Petrov; V. I. Lozhkin

    2003-01-01

    The accuracy of the results of analysis by inductively coupled plasma mass spectrometry (ICP-MS) was studied for the determination of rare-earth elements in black shales rich with a carbonaceous organic substance of a different nature: biogenic (samples SChS-1 and SLg-1, which were put through certification studies at the Institute of Geochemistry, Siberian Division, Russian Academy of Sciences) and bituminous (SDO-1

  7. Experimental geochemistry of Pu and Sm and the thermodynamics of trace element partitioning

    NASA Technical Reports Server (NTRS)

    Jones, John H.; Burnett, Donald S.

    1987-01-01

    An experimental study of the partitioning of Pu and Sm between diopside/liquid and whitlockite/liquid supports the hypothesis that Pu behaves as a light rare earth element during igneous processes in reducing environments. D-Pu/D-Sm is found to be about 2 for both diopsidic pyroxene and whitlockite, and the amount of fractionation would be decreased further if Pu were compared to Ce or Nd. Data indicate that temperature, rather than melt composition, is the most important control on elemental partitioning, and that P2O5 in aluminosilicate melts serves as a complexing agent for the actinides and lanthanides.

  8. The relationship between soil geochemistry and the bioaccessibility of trace elements in playground soil.

    PubMed

    De Miguel, Eduardo; Mingot, Juan; Chacón, Enrique; Charlesworth, Susanne

    2012-12-01

    A total of 32 samples of surficial soil were collected from 16 playground areas in Madrid (Spain), in order to investigate the importance of the geochemistry of the soil on subsequent bioaccessibility of trace elements. The in vitro bioaccessibility of As, Co, Cr, Cu, Ni, Pb and Zn was evaluated by means of two extraction processes that simulate the gastric environment and one that reproduces a gastric + intestinal digestion sequence. The results of the in vitro bioaccessibility were compared against aqua regia extractions ("total" concentration), and it was found that total concentrations of As, Cu, Pb and Zn were double those of bioaccessible values, whilst that of Cr was ten times higher. Whereas the results of the gastric + intestinal extraction were affected by a high uncertainty, both gastric methods offered very similar and consistent results, with bioaccessibilities following the order: As = Cu = Pb = Zn > Co > Ni > Cr, and ranging from 63 to 7 %. Selected soil properties including pH, organic matter, Fe and CaCO(3) content were determined to assess their influence on trace element bioaccessibility, and it was found that Cu, Pb and Zn were predominantly bound to organic matter and, to a lesser extent, Fe oxides. The former fraction was readily accessible in the gastric solution, whereas Fe oxides seemed to recapture negatively charged chloride complexes of these elements in the gastric solution, lowering their bioaccessibility. The homogeneous pH of the playground soils included in the study does not influence trace element bioaccessibility to any significant extent except for Cr, where the very low gastric accessibility seems to be related to the strongly pH-dependent formation of complexes with organic matter. The results for As, which have been previously described and discussed in detail in Mingot et al. (Chemosphere 84: 1386-1391, 2011), indicate a high gastric bioaccessibility for this element as a consequence of its strong association with calcium carbonate and the ease with which these bonds are broken in the gastric solution. The calculation of risk assessments are therefore dependant on the methodology used and the specific environment they address. This has impacts on management strategies formulated to ensure that the most vulnerable of society, children, can live and play without adverse consequences to their health. PMID:23053927

  9. Archean granulite gneisses from eastern Hebei Province, China: rare earth geochemistry and tectonic implications

    NASA Astrophysics Data System (ADS)

    Jahn, Bor-Ming; Zhang, Zong-Qing

    1984-03-01

    The granulite gneisses and their retrograded products of the Qianxi Group from eastern Hebei Province, China, have been investigated for their isotope and trace element geochemistry. A consistent age of about 2.5 AE has been obtained by the Rb-Sr and Sm-Nd whole-rock isochron methods, in agreement with the zircon U-Pb data (Pidgeon 1980; D.Y. Liu, unpubl.). Geochemical arguments from initial isotopic ratios (ISr and INd) and elemental distribution patterns have led us to conclude that this age of about 2.5 AE represents the time of granulite facies metamorphism, which must have followed closely the primary emplacement of their protoliths. Previous claims for early Archean ages (>3.5 AE) of these granulites are not substantiated. The mineral isotope systematics register an important thermal event at about 1.7 AE, roughly corresponding to the time of the widespread Luliang Orogeny (Ma and Wu 1981) or Chungtiao Movement (Huang 1978). The granulites of the Qianxi Group have diverse compositions ranging from ultrabasic through basic-intermediate to acid. Discriminant function calculations suggest that most analyzed samples have igneous parentage. Only a few show characteristics of metasedimentary rocks. The igneous protoliths apparently belong to two series — tholeiitic and calc-alkaline, with the latter dominating in abundance. The majority of the acid granulites have compositions corresponding to tonalite-granodiorite. Except for ultrabasic and metasedimentary rocks, all REE patterns are significantly fractionated with LREE enrichment. The degree of fractionation, as measured by the (La/Yb)N ratios, is most important in the acid granulites. These rocks often show positive Eu anomalies and HREE depletions that are typical of Archean TTG rocks (tonalitetrondhjemite-granodiorite). The existence of komatiites has been previously reported in this region. Although a few rocks have a major element chemistry similar to that for peridotitic komatiites, the lack of associated members in a komatiitic series and the scarcity of REE data have not confirmed the true komatiite occurrence in this region. Many Qianxi granulites are highly depleted in Rb relative to K and Sr. This preferential Rb depletion during granulite facies metamorphism has led to very high K/Rb and very low Rb/Sr ratios. The most comparable case is found in Lewisian granulites. Although the fractionated REE patterns of the basic granulites somewhat resemble those of continental flood basalts, the highly different abundances in other incompatible elements (Ti, Zr, and Ba) readily distinguish them from each other. Nevertheless, the LREE enriched patterns of the basic granulites may suggest an origin of their protoliths by partial melting of LREE-enriched mantle sources. On the other hand, the REE patterns of acid granulites suggest that their protoliths could be derived by partial melting of quartz eclogite, amphibolite or basic granulite. The close time relationship for a series of geologic events, namely, from initial melting of mantle peridotites, through fractional crystallisation of basaltic magmas, to granulite facies metamorphism, seems to occur in many granulite terrains. This relationship, together with the juxtaposition of lithologies of different origins and the exceptionally high pressure conditions (>10 Kb) can be best explained by crustal underplating combined with intracrustal thin-skinned thrusting and stacking of crustal slices. The “andesitic or island arc” model for the formation of the lower continental crust is not in good agreement with the present geochemical data.

  10. Sc, Y, La-Lu - Rare Earth Elements

    SciTech Connect

    Not Available

    1987-01-01

    At present extensive efforts are being made in completing work on system number Rare Earth Elements. Part A is devoted to the occurrence of these elements on the earth and in the universe. Part B deals with the pure metals; the 7 volumes published cover the description of the separation from the raw materials, the preparation of pure metals,their uses and toxicology, the physical properties of nuclei, atoms, molecules, and isotopes; in addition the behavior of ions in solution and the electrochemical behavior of rare earth elements are described. The compounds are described in Part C. Part D with 6 volumes has been devoted to the description of coordination compounds and is completed. The volume ''Rare Earth Elements C 10'' deals with the rare earth tellurides, oxide tellurides, tellurates, telluride halides, tellurate halides, sulfide tellurides, selenide tellurides, and alkali rare earth tellurates. Another topic of this volume are the compounds of the rare earth elements with polonium. So far as meaningful and in accordance with all earlier volumes of ''Rare Earth Elements'' Series C, comparative data are presented in sections preceding treatment of the individual compounds and systems.

  11. Highly siderophile elements in Earth's mantle as a clock for the Moon-forming impact

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.; Morbidelli, Alessandro; Raymond, Sean N.; O'Brien, David P.; Walsh, Kevin J.; Rubie, David C.

    2014-04-01

    According to the generally accepted scenario, the last giant impact on Earth formed the Moon and initiated the final phase of core formation by melting Earth's mantle. A key goal of geochemistry is to date this event, but different ages have been proposed. Some argue for an early Moon-forming event, approximately 30 million years (Myr) after the condensation of the first solids in the Solar System, whereas others claim a date later than 50 Myr (and possibly as late as around 100 Myr) after condensation. Here we show that a Moon-forming event at 40 Myr after condensation, or earlier, is ruled out at a 99.9 per cent confidence level. We use a large number of N-body simulations to demonstrate a relationship between the time of the last giant impact on an Earth-like planet and the amount of mass subsequently added during the era known as Late Accretion. As the last giant impact is delayed, the late-accreted mass decreases in a predictable fashion. This relationship exists within both the classical scenario and the Grand Tack scenario of terrestrial planet formation, and holds across a wide range of disk conditions. The concentration of highly siderophile elements (HSEs) in Earth's mantle constrains the mass of chondritic material added to Earth during Late Accretion. Using HSE abundance measurements, we determine a Moon-formation age of 95 +/- 32 Myr after condensation. The possibility exists that some late projectiles were differentiated and left an incomplete HSE record in Earth's mantle. Even in this case, various isotopic constraints strongly suggest that the late-accreted mass did not exceed 1 per cent of Earth's mass, and so the HSE clock still robustly limits the timing of the Moon-forming event to significantly later than 40 Myr after condensation.

  12. Rare earth elements in seawater near hydrothermal vents

    Microsoft Academic Search

    G. Klinkhammer; H. Elderfield; A. Hudson

    1983-01-01

    Rare earth element (REE) patterns in the deep Pacific are strongly depleted in the lighter elements and have a large negative cerium anomaly. These REE patterns and associated concentration-depth profiles are maintained by regeneration in deep waters modified by preferential scavenging of the lighter elements. Scavenging by iron- and manganese-rich hydrothermal plumes might explain why vast areas of sediments far

  13. UPb dates and trace-element geochemistry of zircon from migmatite, Western Gneiss Region, Norway: Significance for history of partial melting

    E-print Network

    Fossen, Haakon

    U­Pb dates and trace-element geochemistry of zircon from migmatite, Western Gneiss Region, Norway and trace-element analyses for zircon from a variety of textural types of leucosome, from layer-parallel to crosscutting. Zircon textures (euhedral, oscillatory- and sector-zone grains) indicate a likely magmatic origin

  14. Minor-element and Sr-isotope geochemistry of tertiary stocks, Colorado mineral belt

    USGS Publications Warehouse

    Simmons, E.C.; Hedge, C.E.

    1978-01-01

    Rocks of the northeast portion of the Colorado mineral belt form two petrographically, chemically and geographically distinct rock suites: (1) a silica oversaturated granodiorite suite; and (2) a silica saturated, high alkali monzonite suite. Rocks of the granodiorite suite generally have Sr contents less than 1000 ppm, subparallel REE patterns and initial 87Sr/ 86Sr ratios greater than 0.707. Rocks of the monzonite suite are restricted to the northeast part of the mineral belt, where few rocks of the granodiorite suite occur, and generally have Sr contents greater than 1000 ppm, highly variable REE patterns and 87Sr/86Sr initial ratios less than 0.706. Despite forming simple, smooth trends on major element variation diagrams, trace element data for rocks of the granodiorite suite indicate that they were not derived from a single magma. These rocks were derived from magmas having similar REE patterns, but variable Rb and Sr contents, and Rb/Sr ratios. The preferred explanation for these rocks is that they were derived by partial melting of a mixed source, which yielded pyroxene granulite or pyroxenite residues. The monzonite suite is chemically and petrographically more complex than the granodiorite suite. It is subdivided here into alkalic and mafic monzonites, and quartz syenites, based on the textural relations of their ferromagnesian phases and quartz. The geochemistry of these three rock types require derivation from separate and chemically distinct magma types. The preferred explanation for the alkalic monzonites is derivation from a heterogeneous mafic source, leaving a residue dominated by garnet and clinopyroxene. Early crystallization of sphene from these magmas was responsible for the severe depletion of the REE observed in the residual magmas. The lower Sr content and higher Rb/Sr ratios of the mafic monzonites requires a plagioclase-bearing source. The Sr-isotope systematics of the majority of these rocks are interpreted to be largely primary, and not the result of crustal contamination. The positive correlation of Rb/Sr and 87Sr/86Sr ratios for the least fractionated samples indicate that the sources from which parent magmas of both the granodiorite and monzonite suites were derived are Precambrian in age. ?? 1978 Springer-Verlag.

  15. Rare earth elements in soil and plant systems - A review

    Microsoft Academic Search

    Germund Tyler

    2004-01-01

    The rare earth elements (REEs) form a chemically uniform group and include yttrium (Y), lanthanum (La) and the lanthanides\\u000a cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb),\\u000a dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). Their average abundance in the\\u000a Earth’s crust range from 66µg g?1 in

  16. RAPID RADIOCHEMICAL SEPARATION AND ACTIVATION ANALYSIS OF RARE EARTH ELEMENTS

    Microsoft Academic Search

    K. Rengan; W. W. Meinke

    1962-01-01

    Rapid separation of different rare earth elements was effected in ten to ; sixteen minutes with a small cation exchange resin column and alpha -hydroxy-; isobutyric acid as eluent. Individual rare earth fractions could be obtained ; with controlled eluent concentrations and pH. Good separation with peak to ; valley ratio between 50 and 100 in the elution curves was

  17. Determination of rare earth elements in plant protoplasts by MAA

    Microsoft Academic Search

    Zhiyong Zhang; Yuqi Wang; Jingxin Sun; Fuliang Li; Zhifang Chai; Lei Xu; Xin Li; Guoyin Cao

    2000-01-01

    A preliminary study on the speciation of rare earth elements in plant cells has been carried out by molecular activation analysis\\u000a (MAA). Mesophyll protoplasts ofBrassica napus were isolated by enzymatic digestion. After being washed with isosmotic solution containing EDTA for several times, the protoplasts\\u000a were purified by gradient centrifugation. Then the concentration of rare earth elements (REEs) in the protoplasts

  18. Trace element geochemistry of ordinary chondrite chondrules: the type I/type II chondrule dichotomy

    E-print Network

    Jacquet, Emmanuel; Gounelle, Matthieu

    2015-01-01

    We report trace element concentrations of silicate phases in chondrules from LL3 ordinary chondrites Bishunpur and Semarkona. Results are similar to previously reported data for carbonaceous chondrites, with rare earth element (REE) concentrations increasing in the sequence olivine ~ 10 K/h) than type I chondrules. Appreciable Na concentrations (3-221 ppm) are measured in olivine from both chondrule types; type II chondrules seem to have behaved as closed systems, which may require chondrule formation in the vicinity of protoplanets or planetesimals. At any rate, higher solid concentrations in type II chondrule forming regions may explain the higher oxygen fugacities they record compared to type I chondrules. Type I and type II chondrules formed in different environments and the correlation between high solid concentrations and/or oxygen fugacities with rapid cooling rates is a key constraint that chondrule formation models must account for.

  19. 1 INTRODUCTION The rare earth elements (REE's) form a unique

    E-print Network

    Chen, Zhongxing

    1 INTRODUCTION The rare earth elements (REE's) form a unique chemical set wherein the gradual waters this results in the light REE's being more readily adsorbed to particle surfaces than the heavier REE's. In contrast, the heavy REE's are more strongly complexed in solution than the lighter elements

  20. RARE EARTH ELEMENT SENSITIVITY FACTORS IN CALCIC PLAGIOCLASE (ANORTHITE)

    E-print Network

    , and the resulting mass spectrum was deconvolved in the REE mass region into elemental and monoxide components. REE Brookings Drive, St. Louis, MO 63130 1. Introduction The rare earth elements (REE) are sensitive indicators microprobe analyses of the REE on individual minerals within a petrographic context has become increasingly

  1. Geochemistry of rare and minor elements in sediments from Brazil Basin of Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Vvedenskaya, Irina; Dubinin, Alexander

    2010-05-01

    This paper reviews the features of the rare and minor elements in the sediment samples recovered from the Brazil Basin at the location of the Station No. 1537 in the Atlantic Ocean during the 18th cruise of the Research Vessel "Akademik Sergey Vavilov". The depth of the sediment column is 470 cm. The sediments are represented by the oxidized miopelagic clay (0-305 cm) which are underlain by the thin bedded Ethmodiscus diatom oozes (305-470 cm). The brown miopelagic clay (0.09-1.25% ????3, 0.05-0.28% ?organic) predominately consist of the clay minerals (91-97%). The top section sediments also include some terrigenous clastic sandy-silt minerals (1-5%), diatoms (up to 2%), manganese micronodules (approx. 1%), occasional spicules, radiolarian, coccoliths and marine fossil fragments. The transition to the lower diatom oozes is associated with the lens-shape structures and increase in the content of diatoms in clay. The age of sediments at the station No. 1537 is Late Pleistocene. Presence of thin bedded Ethmodiscus oozes is an indirect evidence of re-deposition of the sediments in the central part of the Brazil Basin The chemical composition has been analyzed on 37 core samples recovered from the column. These core samples have been used to define the content of the chemical composition as well as the rare and minor elements. The manganese content in the top section of the miopelagic clay varies insignificantly and value is close 0.46%. The rare and minor elements content in the miopelagic clay is quite stable. The sharp increase in manganese content (to 1.16%) as well as in that of the minor elements such as Co, Cu, Ni, Mo and Tl are observed at the 305-308 cm horizon which corresponds to the bottom of the miopelagic clay. Than, the manganese content decreases to reach its minimum value (0.20%) immediately below this horizon. With further depth increase, the content of manganese starts rising again reaces its maximum value of 2.31% at the 405-407 cm horizon. The diatom oozes, compared with the clayey silts, contain higher concentrations of Co, Cu, Ni, Mo, Tl. The content of other minor elements is considerably lower than that of the clayey silts. Comparison of the average chemical element contents in miopelagic clay and diatom oozes gives a series sequence of abundance of minor elements: Ag Mo Tl Mn Cd Ba Co Ni Cu Sr Pb Li Ce Zn V 0.2 0.4 0.5 0.5 0.6 1.2 1.3 1.5 1.7 1.8 2.1 2.1 2.1 2.1 2.3 REE Y U W Th Be Rb Cs As 2.3-2.1 2.3 2.4 2.4 2.4 2.4 2.4 2.5 3.5 The miopelagic muds contains high concentrations are reached in three groups of elements: easily hydrolyze elements (REE, Y, Th, Be), elements represented by oxyanions in the ocean water (U, W, V, As) and elements linked with the clays (Li, Rb, Cs). The concentrations of rare earth elements (REE) in miopelagic muds show almost no change with depth. The compositions of REE include cerium anomaly and light lanthanides. The composition of REE in diatom oozes is more variable. The oozes also include cerium anomaly, but sometimes concentrations of lighter elements are low.

  2. Rare earth elements and other trace elements in wastewater treatment sludges

    Microsoft Academic Search

    Akira Kawasaki; Ryosuke Kimura; Shigemitsu Arai

    1998-01-01

    In order to evaluate the possibility of contamination of soil with trace elements by the application of sludges to soil, the contents of rare earth elements (REEs; La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) and other trace elements (Be, As, Ag, Cd, Sb, Cs, Bi, and U) in wastewater treatment sludges were determined.

  3. Distribution characteristics of rare earth elements in plants from a rare earth ore area

    Microsoft Academic Search

    Z. Y. Zhang; Y. Q. Wang; F. L. Li; H. Q. Xiao; Z. F. Chai

    2002-01-01

    The contents of eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in various plant species taken from a rare earth ore area were determined by instrumental neutron activation analysis. For a given plant, the REE patterns in root, leaf and host soil are different from each other. The REE distribution characteristics in roots of various

  4. Systematic variation of rare-earth elements in cerium-earth minerals

    USGS Publications Warehouse

    Murata, K.J.; Rose, H.J., Jr.; Carron, M.K.; Glass, J.J.

    1957-01-01

    In a continuation of a study reported previously, rare-earth elements and thorium have been determined in monazite, allanite, cerite, bastnaesite, and a number of miscellaneous cerium-earth minerals. A quantity called sigma (???), which is the sum of the atomic percentages of La, Ce, and Pr, is proposed as an index of composition of all cerium-earth minerals with respect to the rare-earth elements. The value of ??? for all of the minerals analysed falls between 58 and 92 atomic per cent. Monazites, allanites, and cerites cover the entire observed range, whereas bastnaesites are sharply restricted to the range between 80 and 92 atomic per cent. The minimum value of ??? for a cerium-earth mineral corresponds to the smallest possible unit-cell size of the mineral. In monazite, this structurally controlled minimum value of ??? is estimated to be around 30 atomic per cent. Neodymium, because of its abundance, and yttrium, because of its small size, have dominant roles in contraction of the structure. In the other direction, the limit of variation in composition will be reached when lanthanum becomes the sole rare-earth element in a cerium-earth mineral. Cerium-earth minerals from alkalic rocks are all characterized by values of ??? greater than 80 atomic per cent, indicating that the processes that formed these rocks were unusually efficient in fractionating the rare-earth elements-efficient in the sense that a highly selected assemblage is produced without eliminating the bulk of these elements. Analyses of inner and outer parts of two large crystals of monazite from different deposits show no difference in ??? in one crystal and a slightly smaller value of ??? in the outer part of the other crystal compared to the inner part. The ??? of monazites from pegmatites that intrude genetically related granitic rocks in North Carolina is found to be either higher or lower than the ??? of monazites in the intruded host rock. These results indicate that the fractionation of the rare-earth elements is not a simple unidirectional process. When a cerium-earth mineral undergoes replacement, its rare-earth elements may be fractionated into two parts, one forming a new mineral with ??? that is smaller, and the other a second new mineral with ??? that is larger than that of the original mineral. The complete analysis of a cerium-earth mineral to determine its ??? is time consuming. The discovery of a direct relationship between ??? and the Ce/(Nd + Y) atomic ratio in cerium earth minerals allows a rapid determination of ??? from spectrograms obtained in a previously described method for determining thorium in these minerals. ?? 1957.

  5. Study on separation of rare earth elements in complex system

    Microsoft Academic Search

    Hongtao CHANG; Mei LI; Zhaogang LIU; Yanhong HU; Fushun ZHANG

    2010-01-01

    The effect of the feed acidity, acetic acid concentration and rare earth concentration on the distribution ratio, separation coefficient and extraction capacity of light rare earth elements were studied in the P204(DEHPA)-HCl system and P507(HEH\\/EHP)-HCl system both containing acetic acid, respectively. The results showed that the distribution ratio and separation coefficient decreased with increasing of acidity, and increased with increasing

  6. Major and trace element geochemistry of Lake Bogoria and Lake Nakuru, Kenya, during extreme draught

    PubMed Central

    Jirsa, Franz; Gruber, Martin; Stojanovic, Anja; Omondi, Steve Odour; Mader, Dieter; Körner, Wilfried; Schagerl, Michael

    2013-01-01

    The physico-chemical properties of water samples from the two athalassic endorheic lakes Bogoria and Nakuru in Kenya were analysed. Surface water samples were taken between July 2008 and October 2009 in weekly intervals from each lake. The following parameters were determined: pH, salinity, electric conductivity, dissolved organic carbon (DOC), the major cations (FAAS and ICP-OES) and the major anions (IC), as well as certain trace elements (ICP-OES). Samples of superficial sediments were taken in October 2009 and examined using Instrumental Neutron Activation Analysis (INAA) for their major and trace element content including rare earth elements (REE). Both lakes are highly alkaline with a dominance of Na > K > Si > Ca in cations and HCO3 > CO3 > Cl > F > SO4 in anions. Both lakes also exhibited high concentrations of Mo, As and fluoride. Due to an extreme draught from March to October 2009, the water level of Lake Nakuru dropped significantly. This created drastic evapoconcentration, with the total salinity rising from about 20‰ up to 63‰. Most parameters (DOC, Na, K, Ca, F, Mo and As) increased with falling water levels. A clear change in the quality of DOC was observed, followed by an almost complete depletion of dissolved Fe from the water phase. In Lake Bogoria the evapoconcentration effects were less pronounced (total salinity changed from about 40‰ to 48‰). The distributions of REE in the superficial sediments of Lake Nakuru and Lake Bogoria are presented here for the first time. The results show a high abundance of the REE and a very distinct Eu depletion of Eu/Eu* = 0.33–0.45. PMID:25843965

  7. Trace element geochemistry of altered volcanic ash layers (tonsteins) in late Permian coal-bearing formations of eastern Yunnan and western Guizhou Provinces, China

    USGS Publications Warehouse

    Zhou, Y.; Bohor, B.F.; Ren, Y.

    2000-01-01

    Trace element compositions were determined (by instrumental neutron activation analysis; INAA) in 30 samples of synsedimentary volcanic ash-derived tonsteins and detrital claystones from coal seams within the late Permian coal-bearing formation of eastern Yunnan and western Guizhou Provinces, China. The characteristics of trace-element geochemistry in the tonsteins can be distinguished from those of detrital claystones because of the former's unique volcanic-ash origin. The detrital claystones are characterized by their relatively high content of V, Ti, Sc, Cr, Co and Ni, relatively low content of Th and U, Th/U ratio, and small negative Eu anomaly (Eu/Eu* 0.63-0.93). Overall, these trace element characteristics are consistent with a mafic source similar to the composition of basalt rocks in the erosional region on the western edge of the study area. In contrast, the tonsteins are low in V, Ti, Sc, Cr, Co and Ni contents and have a high Th/U ratio with a distinct negative Eu anomaly (Eu/Eu* normally in the range of 0.2-0.4), consistent with a silicic magmatic source. Within the group of tonsteins, those from the lower section (P2.1) of the coal-bearing formation are relatively high in Ti, Zr, Hf, Nb, Ta and rare earth elements (REE), as compared to those from the middle and upper sections (P2.2+3). In trace-element discrimination diagrams (scatter plots) of Hf-Ta, Ti-Ta, Ti-V, Hf-Sc, Lu-Hf and Lu-Th, tonsteins from the P2.1 horizon always fall in isolated distribution areas, separate from the tonsteins of the P2.2+3 horizon. These results suggest that the source materials of tonsteins from the two separate horizons were probably derived from volcanic ash falls of two distinctly different natures. Based on a comparison of the concentrations and assemblages of trace elements between various magmatic rocks, the source materials of tonsteins from P2.1 horizon were mostly composed of calc-alkalic, silica-poor volcanic ash (similar to rhyodacitic magma), whereas those from P2.+3 were apparently more siliceous and K-rich (rhyolitic magma). Thus, tonsteins from the two different horizons are characterized by unique geochemical properties, which remain constant over a wide lateral extent. Integration of trace-elemental compositions with mineralogical and textural observations makes possible the establishment of tonstein stratigraphy, thus, facilitating more precise and reliable coal-seam correlations. (C) 2000 Elsevier Science B.V. All rights reserved.Trace element compositions were determined in 30 samples of synsedimentary volcanic ash-derived tonsteins and detrital claystones from coal seams within the late Permian coal-bearing formation of eastern Yunnan and western Guizhou Provinces, China. The characteristics of trace-element geochemistry in the tonsteins can be distinguished from those of detrital claystones because of the former's unique volcanic-ash origin. The detrital claystones are characterized by their relatively high content of V, Ti, Sc, CR, Co and Ni, relatively low content of Th and U, Th/U ratio, and small negative Eu anomaly.

  8. Determination of thorium and of rare earth elements in cerium earth minerals and ores

    USGS Publications Warehouse

    Carron, M.K.; Skinner, D.L.; Stevens, R.E.

    1955-01-01

    The conventional oxalate method for precipitating thorium and the rare earth elements in acid solution exhibits definite solubilities of these elements. The present work was undertaken to establish conditions overcoming these solubilities and to find optimum conditions for precipitating thorium and the rare earth elements as hydroxides and sebacates. The investigations resulted in a reliable procedure applicable to samples in which the cerium group elements predominate. The oxalate precipitations are made from homogeneous solution at pH 2 by adding a prepared solution of anhydrous oxalic acid in methanol instead of the more expensive crystalline methyl oxalate. Calcium is added as a carrier. Quantitative precipitation of thorium and the rare earth elements is ascertained by further small additions of calcium to the supernatant liquid, until the added calcium precipitates as oxalate within 2 minutes. Calcium is removed by precipitating the hydroxides of thorium and rare earths at room temperature by adding ammonium hydroxide to pH > 10. Thorium is separated as the sebacate at pH 2.5, and the rare earths are precipitated with ammonium sebacate at pH 9. Maximum errors for combined weights of thorium and rare earth oxides on synthetic mixtures are ??0.6 mg. Maximum error for separated thoria is ??0.5 mg.

  9. Variations in trace element geochemistry in the Seine River Basin based on floodplain deposits and bed sediments

    USGS Publications Warehouse

    Horowitz, A.J.; Meybeck, M.; Idlafkih, Z.; Biger, E.

    1999-01-01

    Between 1990 and 1995 a series of bed sediment, suspended sediment and fresh floodplain samples were collected within the Seine River Basin, in France, to evaluate variations in trace element geochemistry. Average background trace element levels for the basin were determined from the collection and subsequent analyses of bed sediment samples from small rural watersheds and from a prehistoric (5000 BP) site in Paris. Concentrations are relatively low, and similar to those observed for fine-grained bed sediments from unaffected areas in the United States and Canada. However, the concentrations are somewhat higher than the reference levels presently adopted by French water authorities for areas north of the Seine Basin, which have similar bedrock lithologies. Downstream trace element variations were monitored in 1994 and 1995 using fresh surficial floodplain samples that were collected either as dried deposits a few days after peak discharge, or immediately after peak discharge (under ??? 30 cm of water). Chemical comparisons between fresh floodplain deposits, and actual suspended sediments collected during flood events, indicate that, with some caveats, the former can be used as surrogates for the latter. The floodplain sediment chemical data indicate that within the Seine Basin, from the relatively unaffected headwaters through heavily affected urban streams, trace element concentrations vary by as much as three orders of magnitude. These trace element changes appear to be the result of both increases in population as well as concomitant increases in industrial activity. This article is a US government work and is in the public domain in the United States.

  10. Speciation of rare earth elements in soil and accumulation by wheat with rare earth fertilizer application

    Microsoft Academic Search

    Shuzhen Zhang; Xiao-quan Shan

    2001-01-01

    A greenhouse study was conducted to investigate the accumulation of rare earth elements (REEs), La, Ce, Pr and Nd, in winter wheat (Triticum aestivum L.), and the speciation of these elements in soil following the application of REE-based fertilizers. Improved crop yield was confirmed by the experiment. The accumulation behavior of La, Ce, Pr and Nd in wheat varied depending

  11. Artificial Radioactivity of Dysprosium and other Rare Earth Elements

    Microsoft Academic Search

    G. Hevesy; Hilde Levi

    1935-01-01

    IN their pioneer work on artificial radioactivity through neutron bombardment, Fermi and his collaborators announced the discovery of the activity of some of the rare earth elements, namely, of lanthanum, praseodymium, neodymium, samarium and gadolinium. Recently, Sugden1 found that terbium shows an appreciable, and europium a very strong, radioactivity after bombardment with neutrons. We find that dysprosium shows an unusually

  12. Standard reference water samples for rare earth element determinations

    Microsoft Academic Search

    P. L. Verplanck; R. C. Antweiler; D. K. Nordstrom; H. E. Taylor

    2001-01-01

    Standard reference water samples (SRWS) were collected from two mine sites, one near Ophir, CO, USA and the other near Redding, CA, USA. The samples were filtered, preserved, and analyzed for rare earth element (REE) concentrations (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) by inductively coupled plasma-mass spectrometry (ICP-MS). These two samples

  13. Accumulation of environmental residues of rare earth elements in sugarcane

    Microsoft Academic Search

    Y. H. Kwang; Q. Y. Liu; X. H. Liu

    1998-01-01

    Increased applications of rare earth elements (REEs) have led to scattering and bio-accumulation in the environment. This study shows that the environmental residue of cerium as a representative for REEs could enter into sugarcane plants via the leaves that were exposed to atmospheric contaminants and REEs could also enter into sugarcane plants via the roots in substrate soils that were

  14. A review of fractionations of rare earth elements in plants

    Microsoft Academic Search

    Tao LIANG; Shiming DING; Wenchong SONG; Zhongyi CHONG; Chaosheng ZHANG; Haitao LI

    2008-01-01

    Studies were carried out on several aspects of rare earth elements (REEs), such as the theory and practice of their applications in agriculture, their geochemical behaviors in natural and agricultural ecosystems, the mechanisms for the increase of crop yield using REE fertilizer, and their toxicology. However, limited knowledge was available for the transfer processes and the features and mechanisms of

  15. Gamma Activation Analysis of Rare Earth Elements in Uranium Rocks

    Microsoft Academic Search

    A. P. Tonchev; B. Gleisberg; Ch. G. Christov; F. G. Kondev; L. P. Kulkina; N. P. Balabanov; V. D. Tcholakov

    1991-01-01

    A method is proposed for the chemical separation of the rare earth elements (REE) in samples with a high uranium content (0.1% to 3%) with the subsequent ?-ray irradiation in the microtron MT-25. For the quantitative determination of REE the relative analysis method was used. The method allows to analyse the massive samples (from 3 to 10 g) and provides

  16. Effects of rare earth elements on the distribution of mineral elements and heavy metals in horseradish

    Microsoft Academic Search

    Lihong Wang; Xiaohua Huang; Qing Zhou

    2008-01-01

    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.

  17. The aqueous geochemistry of rare earth elements: V. Application of photoacoustic spectroscopy to speciation at low rare earth element concentrations

    Microsoft Academic Search

    Scott A. Wood; C. Drew Tait; David R. Janecky; Term L. Constantopoulos

    1995-01-01

    Photoacoustic spectroscopy (PAS) yields information on complexation identical to that obtainable with conventional UV-visible absorption spectroscopy, but is up to three orders of magnitude more sensitive. The applicability of PAS to the study of Er 3+ oxalate and hydroxide complexes, at 25°C and 1 bar, has been demonstrated. Spectra can be obtained at concentrations as low as 10-20 M, and

  18. The aqueous geochemistry of rare earth elements: V. Application of photoacoustic spectroscopy to speciation at low rare earth element concentrations

    Microsoft Academic Search

    Scott A. Wood; C. Drew Tait; David R. Janecky; Term L. Constantopoulos

    1995-01-01

    Photoacoustic spectroscopy (PAS) yields information on complexation identical to that obtainable with conventional UV-visible absorption spectroscopy, but is up to three orders of magnitude more sensitive. The applicability of PAS to the study of Er3+ oxalate and hydroxide complexes, at 25°C and 1 bar, has been demonstrated. Spectra can be obtained at concentrations as low as 10–20 ?M, and observed

  19. 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 samples have distinct Eu anomalies ([Eu]/[Eu*]=1.65~2.86) and others show relatively indistinct Eu anomalies and smooth pattern ((La/Lu)cn=1.48~2.68). Commonly schists have relatively low REE contents (?REE=8~119 ppm) compared to those of other host rocks. Generally, most of the host rock samples have enriched REE contents. Also they have LREE enriched patterns ((La/Lu)cn =1.48~62.32) and various values of Eu anomalies ([Eu]/[Eu*]=0.27~2.87). Also host rocks have negative Ce anomalies ([Ce]/[Ce*])=0.78~0.96). Ce anomaly is used as paleoredox indicator. These Ce values indicate the relatively shallow water environment of late Archean and early Paleoproterozoic in Yishui county, the North China.

  20. Uptake and distribution of rare earth elements in rice seeds cultured in fertilizer solution of rare earth elements

    Microsoft Academic Search

    Dongan Yuan; Xiao-quan Shan; Qing Huai; Bei Wen; Xinru Zhu

    2001-01-01

    The uptake behavior of rare earth elements (REEs) under pot conditions using deionized water and a REE fertilizer solution as the culture media as well as the distribution of REEs in rice proteins were studied. The uptake of REEs in rice seeds increased dramatically after a lag period of approximately three days. Roots can accumulate a much higher content of

  1. Early evolution of the Earth and Moon: new constraints from HfW isotope geochemistry

    Microsoft Academic Search

    Alex Halliday; Mark Rehkämper; Lee der-Chuen; Yi Wen

    1996-01-01

    The W isotopic composition of the bulk silicate Earth (BSE) is chondritic within current analytical uncertainties, indicating that terrestrial core formation commenced more than 50 Myr after the differentiation of the earliest planetesimals in the solar system. This is consistent with UPb data and holds true whether core formation is modelled as a single catastrophic event or as a continuous

  2. Elemental Geochemistry of Sedimentary Rocks at Yellowknife Bay, Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    McLennan, S. M.; Anderson, R. B.; Bell, J. F.; Bridges, J. C.; Calef, F.; Campbell, J. L.; Clark, B. C.; Clegg, S.; Conrad, P.; Cousin, A.; Des Marais, D. J.; Dromart, G.; Dyar, M. D.; Edgar, L. A.; Ehlmann, B. L.; Fabre, C.; Forni, O.; Gasnault, O.; Gellert, R.; Gordon, S.; Grant, J. A.; Grotzinger, J. P.; Gupta, S.; Herkenhoff, K. E.; Hurowitz, J. A.; King, P. L.; Le Mouélic, S.; Leshin, L. A.; Léveillé, R.; Lewis, K. W.; Mangold, N.; Maurice, S.; Ming, D. W.; Morris, R. V.; Nachon, M.; Newsom, H. E.; Ollila, A. M.; Perrett, G. M.; Rice, M. S.; Schmidt, M. E.; Schwenzer, S. P.; Stack, K.; Stolper, E. M.; Sumner, D. Y.; Treiman, A. H.; VanBommel, S.; Vaniman, D. T.; Vasavada, A.; Wiens, R. C.; Yingst, R. A.; Kemppinen, Osku; Bridges, Nathan; Johnson, Jeffrey R.; Minitti, Michelle; Cremers, David; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; Blank, Jennifer; Weigle, Gerald; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Farley, Kenneth; Griffes, Jennifer; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Siebach, Kirsten; Brunet, Claude; Hipkin, Victoria; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Gómez-Elvira, Javier; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; d'Uston, Claude; Lasue, Jérémie; Lee, Qiu-Mei; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Robert, François; Sautter, Violaine; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Goetz, Walter; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Fassett, Caleb; Blake, David F.; Bristow, Thomas; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline

    2014-01-01

    Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicates that magnetite and phyllosilicates formed by diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous conditions. Analyses of diagenetic features (including concretions, raised ridges, and fractures) at high spatial resolution indicate that they are composed of iron- and halogen-rich components, magnesium-iron-chlorine-rich components, and hydrated calcium sulfates, respectively. Composition of a cross-cutting dike-like feature is consistent with sedimentary intrusion. The geochemistry of these sedimentary rocks provides further evidence for diverse depositional and diagenetic sedimentary environments during the early history of Mars.

  3. Rare-earth elements in hot brines (165 to 190 degree C) from the Salton Sea geothermal field

    SciTech Connect

    Lepel, E.A.; Laul, J.C.; Smith, M.R.

    1988-01-01

    Rare-earth element (REE) concentrations are important indicators for revealing various chemical fractionation processes (water/rock interactions) and source region geochemistry. Since the REE patterns are characteristic of geologic materials (basalt, granite, shale, sediments, etc.) and minerals (K-feldspar, calcite, illite, epidote, etc.), their study in geothermal fluids may serve as a geothermometer. The REE study may also enable us to address the issue of groundwater mixing. In addition, the behavior of the REE can serve as analogs of the actinides in radioactive waste (e.g., neodymium is an analog of americium and curium). In this paper, the authors port the REE data for a Salton Sea Geothermal Field (SSGF) brine (two aliquots: port 4 at 165{degree}C and port 5 at 190{degree}C) and six associated core samples.

  4. Uncovering the end uses of the rare earth elements.

    PubMed

    Du, Xiaoyue; Graedel, T E

    2013-09-01

    The rare earth elements (REE) are a group of fifteen elements with unique properties that make them indispensable for a wide variety of emerging and conventional established technologies. However, quantitative knowledge of REE remains sparse, despite the current heightened interest in future availability of the resources. Mining is heavily concentrated in China, whose monopoly position and potential restriction of exports render primary supply vulnerable to short term disruption. We have drawn upon the published literature and unpublished materials in different languages to derive the first quantitative annual domestic production by end use of individual rare earth elements from 1995 to 2007. The information is illustrated in Sankey diagrams for the years 1995 and 2007. Other years are available in the supporting information. Comparing 1995 and 2007, the production of the rare earth elements in China, Japan, and the US changed dramatically in quantities and structure. The information can provide a solid foundation for industries, academic institutions and governments to make decisions and develop strategies. PMID:23602698

  5. Coal fly ash as a resource for rare earth elements.

    PubMed

    Franus, Wojciech; Wiatros-Motyka, Ma?gorzata M; Wdowin, Magdalena

    2015-06-01

    Rare earth elements (REE) have been recognised as critical raw materials, crucial for many clean technologies. As the gap between their global demand and supply increases, the search for their alternative resources becomes more and more important, especially for the countries which depend highly on their import. Coal fly ash (CFA), which when not utilised is considered waste, has been regarded as the possible source of many elements, including REE. Due to the increase in the energy demand, CFA production is expected to grow, making research into the use of this material a necessity. As Poland is the second biggest coal consumer in the European Union, the authors have studied different coal fly ashes from ten Polish power plants for their rare earth element content. All the fly ashes have a broadly similar distribution of rear earth elements, with light REE being dominant. Most of the samples have REE content relatively high and according to Seredin and Dai (Int J Coal Geol 94: 67-93, 2012) classification can be considered promising REE raw materials. PMID:25613802

  6. Rare-earth element variation in phosphate nodules from midcontinent Pennsylvanian cyclothems

    SciTech Connect

    Kidder, D.L. (Ohio Univ., Athens, OH (United States). Dept. of Geological Sciences); Eddy-Dilek, C.A. (Westinghouse Savannah River Co., Aiken, SC (United States). Savannah River Technology Center)

    1994-07-01

    The rare-earth element (REE) geochemistry of phosphate nodules from eastern Kansas and northeastern Oklahoma is dominated by patterns that are generally flat or are enriched in middle REE (MREE). Flat patterns are typical of phosphate nodules preserved in thick shales and in nodules from shales deposited nearest to detrital sources. The flat patterns are probably derived from terrigenous constituents in the host shale. MREE enrichment is evident in phosphate found in relatively thin shales and in distal shales. The authors suggest that the MREE-enriched pattern reflects the contribution of MREE-enriched fecal phosphate. The initial MREE enrichment mechanism may have been analogous to that in which some modern algae preferentially extract MREE from water of marine composition. The MREE-enriched signature may be preserved only in phosphate nodules that formed where terrigenous input was so low that it did not mask the characteristic fecal pattern. Rare Ce depletion patterns reflect a primary seawater REE source that has not been obscured by fecal or detrital components.

  7. Rare earth element distributions and trends in natural waters with a focus on groundwater.

    PubMed

    Noack, Clinton W; Dzombak, David A; Karamalidis, Athanasios K

    2014-04-15

    Systematically varying properties and reactivities have led to focused research of the environmental forensic capabilities of rare earth elements (REE). Increasing anthropogenic inputs to natural systems may permanently alter the natural signatures of REE, motivating characterization of natural REE variability. We compiled and analyzed reported dissolved REE concentration data over a wide range of natural water types (ground-, ocean, river, and lake water) and groundwater chemistries (e.g., fresh, brine, and acidic) with the goal of quantifying the extent of natural REE variability, especially for groundwater systems. Quantitative challenges presented by censored data were addressed with nonparametric distributions and regressions. Reported measurements of REE in natural waters range over nearly 10 orders of magnitude, though the majority of measurements are within 2-4 orders of magnitude, and are highly correlated with one another. Few global correlations exist among dissolved abundance and bulk solution properties in groundwater, indicating the complex nature of source-sink terms and the need for care when comparing results between studies. This collection, homogenization, and analysis of a disparate literature facilitates interstudy comparison and provides insight into the wide range of variables that influence REE geochemistry. PMID:24628583

  8. 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.

  9. Trace element and isotope geochemistry of Cretaceous-Tertiary boundary sediments: identification of extra-terrestrial and volcanic components

    NASA Technical Reports Server (NTRS)

    Margolis, S. V.; Doehne, E. F.

    1988-01-01

    Trace element and stable isotope analyses were performed on a series of sediment samples crossing the Cretaceous-Tertiary (K-T) boundary from critical sections at Aumaya and Sopelano, Spain. The aim is to possibly distinguish extraterrestrial vs. volcanic or authigenic concentration of platinum group and other elements in K-T boundary transitional sediments. These sediments also have been shown to contain evidence for step-wise extinction of several groups of marine invertebrates, associated with negative oxygen and carbon isotope excursions occurring during the last million years of the Cretaceous. These isotope excursions have been interpreted to indicate major changes in ocean thermal regime, circulation, and ecosystems that may be related to multiple events during latest Cretaceous time. Results to date on the petrographic and geochemical analyses of the Late Cretaceous and Early Paleocene sediments indicate that diagenesis has obviously affected the trace element geochemistry and stable isotope compositions at Zumaya. Mineralogical and geochemical analysis of K-T boundary sediments at Zumaya suggest that a substantial fraction of anomalous trace elements in the boundary marl are present in specific mineral phases. Platinum and nickel grains perhaps represent the first direct evidence of siderophile-rich minerals at the boundary. The presence of spinels and Ni-rich particles as inclusions in aluminosilicate spherules from Zumaya suggests an original, non-diagenetic origin for the spherules. Similar spherules from southern Spain (Caravaca), show a strong marine authigenic overprint. This research represents a new approach in trying to directly identify the sedimentary mineral components that are responsible for the trace element concentrations associated with the K-T boundary.

  10. Recovery of rare earths from sludges containing rare-earth elements

    Microsoft Academic Search

    Tetsuji Saito; Hironori Sato; Tetsuichi Motegi

    2006-01-01

    To develop a process for the recovery of rare-earth elements from sludges, a chemical recycling process was applied to neodymium-containing boron trioxide. It was found that the neodymium was successfully extracted as either sodium neodymium sulfate hydrate or neodymium hydroxide from neodymium-containing boron trioxide by this process.

  11. Rare earth elements as geochemical tracers of regional groundwater mixing

    Microsoft Academic Search

    Kevin H. Johannesson; Klaus J. Stetzenbach; Vernon F. Hodge

    1997-01-01

    The rare earth elements (REE) were analyzed in a groundwater system from south-central Nevada (i.e., Ash Meadows National Wildlife Refuge, the Spring Mountains, Pahranagat National Wildlife Refuge, and the Nevada Test Site) in order to investigate their potential use as tracers of regional groundwater flow. Previous investigations using conservative tracers (e.g., deuterium and uranium isotopes) identified recharge in local mountains

  12. Energy-adjusted pseudopotentials for the rare earth elements

    Microsoft Academic Search

    M. Dolg; H. Stoll; A. Savin; H. Preuss

    1989-01-01

    Nonrelativistic and quasirelativistic energy-adjusted pseudopotentials and optimized (7s6p5d)\\/[5s4p3d]-GTO valence basis sets for use in molecular calculations for fixed f-subconfigurations of the rare earth elements, La through Lu, have been generated. Atomic excitation and ionization energies from numerical HF, as well as SCF pseudopotential calculations using the derived basis sets, differ by less than 0.1 eV from numerical HF all-electron results.

  13. 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.

  14. Concentrations of rare earth elements in topsoil from East China

    Microsoft Academic Search

    Tian Yang; Zhaoyu Zhu; Yi Wu; Zhiguo Rao

    2008-01-01

    Fifty topsoil samples collected from 12 different regions of East China have been analyzed for rare earth elements (REEs).\\u000a The average REE concentrations of the 50 topsoil samples are much higher than world average and are characterized by LREE-enrichment,\\u000a HREE-depletion, Eu-depletion and Ce-enrichment. However, the REE concentration is not strongly affected by the climate of\\u000a the sampling site; it is

  15. EXAFS study of rare-earth element coordination in calcite

    Microsoft Academic Search

    E. J. Elzinga; Richard Reeder; S. H. Withers; Robert E. Peale; R. A. Mason; Kenneth M. Beck; Wayne P. Hess

    2002-01-01

    Extended X-ray absorption fine-structure (EXAFS) spectroscopy is used to characterize the local coordination of selected rare-earth elements (Nd3+, Sm3+, Dy3+, Yb3+) coprecipitated with calcite in minor concentrations from room-temperature aqueous solutions. Fitting results confirm substitution in the Ca site, but first-shell Nd-O and Sm-O distances are longer than the Ca-O distance in calcite and longer than what is consistent with

  16. Hydrogeochemistry and rare earth element behavior in a volcanically acidified watershed in Patagonia, Argentina

    E-print Network

    Royer, Dana

    and analyzed for major ions, trace metals, and rare earth elements (REE). The concentrations of REE in the RioHydrogeochemistry and rare earth element behavior in a volcanically acidified watershed to oxidation of sulfide minerals. D 2005 Elsevier B.V. All rights reserved. Keywords: Rare earth elements

  17. Rare earth elements activate endocytosis in plant cells Lihong Wanga,b,1

    E-print Network

    Deng, Xing-Wang

    Rare earth elements activate endocytosis in plant cells Lihong Wanga,b,1 , Jigang Lic,d,1 , Qing (sent for review May 15, 2014) It has long been observed that rare earth elements (REEs) regulate, such as rare earth elements (REEs), have been observed for a long time to be beneficial to plant growth (1, 2

  18. Source and mobility of Rare Earth Elements in a sedimentary aquifer system: Aquitaine basin (Southern France)

    E-print Network

    Paris-Sud XI, Université de

    Source and mobility of Rare Earth Elements in a sedimentary aquifer system: Aquitaine basin Geological Survey Service, Bordeaux, France, e.malcuit@brgm.fr The study of rare earth elements (REEs such as rivers and lakes and groundwaters. Rare earth elements) are of great interest because of their unique

  19. Trace-element geochemistry of diamondite: Crystallisation of diamond from kimberlite–carbonatite melts

    Microsoft Academic Search

    Sonal Rege; W. L. Griffin; G. Kurat; S. E. Jackson; N. J. Pearson; Suzanne Y. O'Reilly

    2008-01-01

    Quantitative trace-element analyses of 38 elements have been carried out in 11 samples of polycrystalline diamond (diamondite) from southern Africa by LAM-ICPMS. The samples are divided into “peridotitic” and “eclogitic” types based on the compositions of garnet and clinopyroxene intergrown with the diamond. The trace-element patterns of the diamondite samples reflect mixtures of diamond and submicroscopic inclusions of fluid±solid phases,

  20. 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.

  1. A review of noble gas geochemistry in relation to early Earth history

    NASA Technical Reports Server (NTRS)

    Kurz, M. D.

    1985-01-01

    One of the most fundamental noble gas constraints on early Earth history is derived from isotopic differences in (129)Xe/(130)Xe between various terrestrial materials. The short half life (17 m.y.) of extinct (129I, parent of (129)Xe, means that these differences must have been produced within the first 100 m.y. after terrestrial accretion. The identification of large anomalies in (129)Xe/(130)Xe in mid ocean ridge basalts (MORB), with respect to atmospheric xenon, suggests that the atmosphere and upper mantle have remained separate since that time. This alone is a very strong argument for early catastrophic degassing, which would be consistent with an early fractionation resulting in core formation. However, noble gas isotopic systematics of oceanic basalts show that the mantle cannot necessarily be regarded as a homogeneous system, since there are significant variations in (3)He/(4)He, (40)Ar/(36)Ar, and (129)Xe/(130)Xe. Therefore, the early degassing cannot be considered to have acted on the whole mantle. The specific mechanisms of degassing, in particular the thickness and growth of the early crust, is an important variable in understanding present day noble gas inventories. Another constraint can be obtained from rocks that are thought to be derived from near the lithosphere asthenosphere boundary: ultramafic xenoliths.

  2. Source and mobility of Rare Earth Elements in a sedimentary aquifer system: Aquitaine basin (Southern France)

    NASA Astrophysics Data System (ADS)

    Negrel, P. J.; Petelet-Giraud, E.; Millot, R.; Malcuit, E.

    2011-12-01

    The study of rare earth elements (REEs) in natural waters initially involved an examination of their occurrence and behavior in seawater and coastal waters such as estuaries. Since the 1990s, REE geochemistry has been applied to continental waters such as rivers and lakes and groundwaters. Rare earth elements) are of great interest because of their unique characteristics and have been used in the study of many geological processes like weathering and water-rock interaction processes, provenance of sediments, etc... With the evolution of analytical techniques like new generation ICP-MS, much attention had been paid towards the water geochemistry of REEs. However, there is a need of more investigations devoted to REEs in large groundwater systems, especially on the understanding of the distribution of REEs and their evolution in such systems. In this frame, large sedimentary aquifer systems often constitute strategic water resources for drinking water supply, agriculture irrigation and industry, but can also represent an energetic resource for geothermal power. Large water abstractions can induce complete modification of the natural functioning of such aquifer systems. These large aquifer systems thus require water management at the basin scale in order to preserve both water quantity and quality. The large Eocene Sand aquifer system of the Aquitaine sedimentary basin was studied through various hydrological, chemical and isotopic tools. This system extends over 116,000 km2 in the South west part of the French territory. The aquifer being artesian in the west of the district and confined with piezometric levels around 250-m depth in the east. The 'Eocene Sands', composed of sandy Tertiary sediments alternating with carbonate deposits, is a multi-layer system with high permeability and a thickness of several tens of metres to a hundred metres. The Eocene Sand aquifer system comprises at least five aquifers: Paleocene, Eocene infra-molassic sands (IMS), early Eocene, middle Eocene, and late Eocene. One important feature, in these confined systems isolated from anthropogenic influence, is the range in salinities by a factor of 10, from 250 mg/L up to 2.5 g/L. The ?REE, in the range 2-54 ng/L, with a dependence on salinity when expressed in % HCO3 or SO4, reflect the carbonate or evaporite source of REEs. The UCC normalized-REE patterns show a large variability as exemplified by the REE flat patterns-low SREE associated with salinity controlled by HCO3. In the present work, the REEs are investigated in terms of saturation indices, speciation modelling, REE patterns in order to recognize the aquifer type hosting groundwater and decipher the origin of the salinity of the groundwater as some part of the aquifer display in the groundwater concentration of chemical element exceeding the drinking water standard (SO4, F...). Such high concentrations of naturally-occurring substances (e.g. unaffected by human activities) can have negative impacts on groundwater thresholds and deciphering their origin by means of geochemical tools like REE is a remaining challenge.

  3. Minor element geochemistry of groundwater from an area with prevailing saline groundwater in Chikhwawa, lower Shire valley (Malawi)

    NASA Astrophysics Data System (ADS)

    Monjerezi, Maurice; Vogt, Rolf D.; Gebru, Asfaw Gebretsadik; Saka, John D. K.; Aagaard, Per

    Groundwater resources with high salinity content are found in some parts of the lower Shire River valley (Malawi). This paper discusses the geochemistry of minor elements with regards to the prevailing salinity. Hierarchical clustering and principal component analyses were used to identify factors which relate to both minor elements and samples and were interpreted as reflecting the influence of prevailing saline/brackish groundwater. Concentrations of lead (Pb), boron (B), strontium (Sr) and chromium (Cr) were associated with groundwater with high content of total dissolved solids (TDS). Speciation calculations indicated that dissolved Sr, barium (Ba) and lithium (Li) were mainly in the form of free aqueous ions whereas hydrolysed species were significant for aluminium (Al) and Cr, and carbonate complexes for Pb. Chloride complexes were prevalent for silver (Ag). Solubility of cerussite (PbCO3) and barite (BaSO4) was shown to act as a control on the levels of Pb and Ba, respectively. Thus, Ba concentrations were very low in saline groundwater owing to their high sulphate content. A relatively variable B concentration in the groundwater samples was explained using a binary mixing model of saline and fresh groundwater. The mixing of fresh groundwater with saline groundwater was concomitant with high Na+/Ca2+ ratios and enrichment of B, probably by desorption from clays. The WHO drinking water guidelines for Ba, B, Cr and Pb were exceeded in 6.5%, 9.7%, 16.1% and 64.5% of all the samples, respectively. However, all samples were below the Malawian specification of B in borehole and shallow well water quality (MS 733:2005) of 5.0 mg/L.

  4. 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.

  5. Trace elemental imaging of rare earth elements discriminates tissues at microscale in flat fossils.

    PubMed

    Gueriau, Pierre; Mocuta, Cristian; Dutheil, Didier B; Cohen, Serge X; Thiaudière, Dominique; Charbonnier, Sylvain; Clément, Gaël; Bertrand, Loïc

    2014-01-01

    The interpretation of flattened fossils remains a major challenge due to compression of their complex anatomies during fossilization, making critical anatomical features invisible or hardly discernible. Key features are often hidden under greatly preserved decay prone tissues, or an unpreparable sedimentary matrix. A method offering access to such anatomical features is of paramount interest to resolve taxonomic affinities and to study fossils after a least possible invasive preparation. Unfortunately, the widely-used X-ray micro-computed tomography, for visualizing hidden or internal structures of a broad range of fossils, is generally inapplicable to flattened specimens, due to the very high differential absorbance in distinct directions. Here we show that synchrotron X-ray fluorescence spectral raster-scanning coupled to spectral decomposition or a much faster Kullback-Leibler divergence based statistical analysis provides microscale visualization of tissues. We imaged exceptionally well-preserved fossils from the Late Cretaceous without needing any prior delicate preparation. The contrasting elemental distributions greatly improved the discrimination of skeletal elements material from both the sedimentary matrix and fossilized soft tissues. Aside content in alkaline earth elements and phosphorus, a critical parameter for tissue discrimination is the distinct amounts of rare earth elements. Local quantification of rare earths may open new avenues for fossil description but also in paleoenvironmental and taphonomical studies. PMID:24489809

  6. Standard reference water samples for rare earth element determinations

    USGS Publications Warehouse

    Verplanck, P.L.; Antweiler, R.C.; Nordstrom, D.K.; Taylor, H.E.

    2001-01-01

    Standard reference water samples (SRWS) were collected from two mine sites, one near Ophir, CO, USA and the other near Redding, CA, USA. The samples were filtered, preserved, and analyzed for rare earth element (REE) concentrations (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) by inductively coupled plasma-mass spectrometry (ICP-MS). These two samples were acid mine waters with elevated concentrations of REEs (0.45-161 ??g/1). Seventeen international laboratories participated in a 'round-robin' chemical analysis program, which made it possible to evaluate the data by robust statistical procedures that are insensitive to outliers. The resulting most probable values are reported. Ten to 15 of the participants also reported values for Ba, Y, and Sc. Field parameters, major ion, and other trace element concentrations, not subject to statistical evaluation, are provided.

  7. Magnetic property improvement of niobium doped with rare earth elements

    NASA Astrophysics Data System (ADS)

    Jiang, Tao; He, Fei-Si; Jiao, Fei; He, Fa; Lu, Xiang-Yang; Zhao, Kui; Zhao, Hong-Yun; You, Yu-Song; Chen, Lin

    2014-05-01

    A new idea is proposed by the PKU group to improve the magnetic properties of the Type-II superconductor niobium. Rare earth elements like scandium and yttrium are doped into ingot niobium during the smelting processes. A series of experiments have been done since 2010. The preliminary testing results show that the magnetic properties of niobium materials have changed with different doping elements and proportions while the superconductive transition temperature does not change very much. This method may increase the superheating magnetic field of niobium so as to improve the performance of the niobium cavity, which is a key component of SRF accelerators. A Tesla-type single-cell cavity made of scandium-doped niobium is being fabricated.

  8. Deciphering tectonic provenance signatures from the trace element geochemistry of igneous zircon

    NASA Astrophysics Data System (ADS)

    Grimes, C. B.; Wooden, J. L.; Vazquez, J. A.

    2011-12-01

    The ability to correlate stable isotope ratios and trace element signatures with age on single crystals, coupled with resistance to chemical and physical weathering make zircon a useful complement in a wide range of geologic investigations. Zircon trace element concentrations broadly reflect parental magma composition, although studies show that crystal chemistry also imparts a significant control on the shape of REE patterns. Concentrations of select elements (e.g., Hf) and various trace element ratios (e.g., Th/U, Yb/Gd, Eu/Eu*) commonly correlate with crystallization temperature (from Ti-in-zircon thermometry) for suites of zircon precipitated during magmatic fractionation in zircon-saturated systems. Other trace element ratios, primarily U/Yb and Th/Yb plotted against Hf or Y discriminate zircon sampled in situ from mid-ocean ridges from those formed in arc-related ('continental') settings. However, these geochemical discriminations are limited in that ~20% of published mid-ocean ridge zircon compositions plot within the 'continental' zircon field and they fail to distinguish zircon from other magmatic settings such as ocean islands. To improve geochemical zircon discrimination diagrams for diverse tectonic environments, trace element criteria that distinguish lavas from different tectonic settings are considered along with a broad suite of elements routinely measured by the Stanford-USGS SHRIMP-RG ion probe. Arc-related magmas exhibit enrichment in large ion lithophile (LIL) elements (i.e., U, Th) with respect to typical MORB, and are depleted in niobium (Nb) with respect to both OIB and MORB lavas. OIB lavas are typically enriched in LIL with respect to MORB, but lack the Nb-depletion characteristic of arcs. The ratios U/Yb, Yb/Nb, and Th/Nb can therefore be used to discriminate lavas from these different settings. Discrimination diagrams based on these elemental ratios in zircon also define separate (though partly overlapping) fields for modern mid-ocean ridges, arcs, and the Hawaii hotspot. Based on existing datasets, juvenile island arc zircons (Izu-Bonin-Mariana) define a separate field from continental arc zircons from the Western US. Fields have been determined from over 1000 in situ analyses of zircon along with published compositions of zircon from the Izu-Bonin-Mariana arc system (Tani et al., 2010, Geology 38:215-218). These new trace element discrimination diagrams can complement geochronologic studies of detrital, xenocrystic, or other ancient zircon populations with an uncertain igneous provenance. In primitive basalts, Nb/Yb ratio is considered an indicator of mantle fertility, whereas LIL/Nb ratios are heavily influenced by slab-derived fluids from subduction. Although co-crystallizing minerals in evolved, zircon-saturated melts will impact trace element ratios, to a first-order we suggest these signatures extend to zircon populations as well.

  9. Major element, REE, and Pb, Nd and Sr isotopic geochemistry of Cenozoic volcanic rocks of eastern China: implications for their origin from suboceanic-type mantle reservoirs

    USGS Publications Warehouse

    Basu, A.R.; Wang, Junwen; Huang, Wankang; Xie, Guanghong; Tatsumoto, M.

    1991-01-01

    Major- and rare-earth-element (REE) concentrations and UThPb, SmNd, and RbSr isotope systematics are reported for Cenozoic volcanic rocks from northeastern and eastern China. These volcanic rocks, characteristically lacking the calc-alkaline suite of orogenic belts, were emplaced in a rift system which formed in response to the subduction of the western Pacific plate beneath the eastern Asiatic continental margin. The rocks sampled range from basanite and alkali olivine basalt, through olivine tholeiite and quartz tholeiite, to potassic basalts, alkali trachytes, pantellerite, and limburgite. These rock suites represent the volcanic centers of Datong, Hanobar, Kuandian, Changbaishan and Wudalianchi in northeastern China, and Mingxi in the Fujian Province of eastern China. The major-element and REE geochemistry is characteristic of each volcanic suite broadly evolving through cogenetic magmatic processes. Some of the outstanding features of the isotopic correlation arrays are as follows: (1) NdSr shows an anticorrelation within the field of ocean island basalts, extending from the MORB end-member to an enriched, time-averaged high Rb Sr and Nd Sr end-member (EM1), (2) SrPb also shows an anticorrelation, similar to that of Hawaiian and walvis Ridge basalts, (3) NdPb shows a positive correlation, and (4) the 207Pb 204Pb vs 206Pb 204Pb plot shows linear arrays parallel to the general trend (NHRL) for MORB on both sides of the geochron, although in the 208Pb 204Pb vs 206Pb 204Pb plot the linear array is significantly displaced above the NHRL in a pattern similar to that of the oceanic island basalts that show the Dupal signatures. In all isotope correlation patterns, the data arrays define two different mantle components-a MORB-like component and an enriched mantle component. The isotopic data presented here clearly demonstrate the existence of Dupal compositions in the sources of the continental volcanic rocks of eastern China. We suggest that the subcontinental mantle beneath eastern China served as the reservoir for the EMI component, and that the MORB component was either introduced by subduction of the Kula-Pacific Ridge beneath the Asiatic plate in the Late Cretaceous, as proposed by Uyeda and Miyashiro, or by upwellings in the subcontinental asthenosphere due to subduction. ?? 1991.

  10. Mimicking the magnetic properties of rare earth elements using superatoms

    PubMed Central

    Cheng, Shi-Bo; Berkdemir, Cuneyt; Castleman, A. W.

    2015-01-01

    Rare earth elements (REs) consist of a very important group in the periodic table that is vital to many modern technologies. The mining process, however, is extremely damaging to the environment, making them low yield and very expensive. Therefore, mimicking the properties of REs in a superatom framework is especially valuable but at the same time, technically challenging and requiring advanced concepts about manipulating properties of atom/molecular complexes. Herein, by using photoelectron imaging spectroscopy, we provide original idea and direct experimental evidence that chosen boron-doped clusters could mimic the magnetic characteristics of REs. Specifically, the neutral LaB and NdB clusters are found to have similar unpaired electrons and magnetic moments as their isovalent REs (namely Nd and Eu, respectively), opening up the great possibility in accomplishing rare earth mimicry. Extension of the superatom concept into the rare earth group not only further shows the power and advance of this concept but also, will stimulate more efforts to explore new superatomic clusters to mimic the chemistry of these heavy atoms, which will be of great importance in designing novel building blocks in the application of cluster-assembled nanomaterials. Additionally, based on these experimental findings, a novel “magic boron” counting rule is proposed to estimate the numbers of unpaired electrons in diatomic LnB clusters. PMID:25848014

  11. Rare Earth Elements--End Use and Recyclability Scientific Investigations Report 20115094

    E-print Network

    Rare Earth Elements--End Use and Recyclability Scientific Investigations Report 2011­5094 U Pass, Calif., mine. The Mountain Pass mine is one of the two largest rare earth mines in the world outside of China. Photograph by Dan Cordier, U.S. Geological Survey. #12;Rare Earth Elements--End Use

  12. Stable isotope and Rare Earth Element evidence for recent ironstone pods within the Archean Barberton

    E-print Network

    Hren, Michael

    Stable isotope and Rare Earth Element evidence for recent ironstone pods within the Archean greenstone belt. We examined oxygen and hydrogen isotopes and Rare Earth Element (REE) concentrations pro- vide a valuable geochemical record of the conditions on the surface of the early Earth. Many

  13. Rare earth element sorption onto hydrous manganese oxide A modeling study

    E-print Network

    Paris-Sud XI, Université de

    37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 Rare earth, Université Rennes 1, CNRS, 35042 Rennes cedex, France Keywords: rare earth element, manganese oxyhydroxides modeling, PHREEQC, PhreePlot 1. Introduction The distributions of rare earth elements (REE) in natural

  14. The elements of the Earth's magnetism and their secular changes between 1550 and 1915

    NASA Technical Reports Server (NTRS)

    Fritsche, H.

    1983-01-01

    The results of an investigation about the magnetic agents outside the Earth's surface as well as the Earth's magnetic elements for the epochs 1550, 1900, 1915 are presented. The secular changes of the Earth's magnetic elements during the time interval 1550 - 1900 are also included.

  15. Research paper Chemical element imaging for speleothem geochemistry: Application to a

    E-print Network

    of the sample. Element maps for calcium (Ca), uranium (U), strontium (Sr) and silicon (Si) showed inverse waters, as suggested by the presence of volcanic suite in the fine fraction of the opal. Opal of environmental changes at different time scales, from season to isotopic stage, this methodology opens new

  16. "EXAFS Study of Rare-Earth Element Coordination in Calcite"

    SciTech Connect

    Elzinga, E. J.; Reeder, Richard; Withers, S. H.; Peale, Robert E.; Mason, R. A.; Beck, Kenneth M.; Hess, Wayne P.

    2002-03-11

    X-ray absorption fine-structure (XAFS) spectroscopy is used to characterize the local coordination of selected rare-earth elements (Nd3+, Sm3+, Dy3+, Yb3+) coprecipitated with calcite in minor concentrations from room-temperature aqueous solutions. Fitting results confirm substitution in the Ca site, but first-shell Nd-O and Sm-O distances are longer than the Ca-O distance in calcite, and longer than consistent with ionic radii sums for 6-fold coordination in the octahedral Ca site. In contrast, first-shell Dy-O and Yb-O distances are shorter than the Ca-O distance and consistent with ionic radii sums for 6-fold coordination. Comparison of Nd-O and Sm-O bond lengths with those in lanthanide sesquioxides and with ionic radii trends across the lanthanide series suggested that Nd3+ and Sm3+ impurities have 7-fold coordination in a modified Ca site in calcite. This would require some disruption of the local structure, with an expected decrease in stability and possibly a different charge compensation mechanism. A possible explanation for the increased coordination for the larger rare earth elements involves bidenate ligation from a CO3 group. Because trivalent actinides such as Am3+ and Cm3+ have ionic radii similar to Nd3+, their incorporation in calcite may result in similar defect structure.

  17. Major Element Geochemistry of Biofilms in a Silica-Precipitating Hot Spring

    NASA Astrophysics Data System (ADS)

    Havig, J. R.; Shock, E. L.; Moore, G.

    2007-12-01

    Hydrothermal biofilm communities represent one of the best present-day representations of early microbial communities, dating back to 2.5 Ga, and possibly 3.8 Ga in the geologic record. Silica-precipitating hydrothermal springs have been thought to have great potential for biosignature preservation. The interactions of hydrothermal water, biofilms, and precipitated siliceous sinter, however, remain poorly constrained. To this end, we collected water and biofilm, as well as contextual sinter and rock samples from various hot springs in Yellowstone National Park. Here we focus on one hot spring in Sentinel Meadow (Lower Geyser Basin), with temperature and pH that vary from the source (93 C, pH 7.4) to the farthest of five collection points down channel (56 C, pH 8.2). Elemental analysis reveals that the biofilms are made up of from <1 to ~11 % dry wt. carbon and ~0.1 to 1% dry wt. nitrogen. Major element analysis via electron microprobe and complimentary x-ray fluorescence show that (excluding C and N from the total) SiO2 constitutes 86 to 94 % dry weight mass, with the rest made up of Al2O3 (3 to 8%), Na2O (1.7 to 3.7%), K2O (0.6 to 1.5%), and minor amounts of FeO, CaO, MgO, and TiO2 (<1%). Local sinter is SiO2 (97.5% dry wt.), Na2O (1.5%), and <1% Al2O3, FeO, K2O, CaO, MgO, and TiO2. In addition, sinter contains measurable amounts of carbon (1.4%) and nitrogen (0.2%). Discrepancies between the biofilm and sinter values show that the geochemical compositions of biofilms are not captured by the precipitating silica. If biofilms accumulated elements strictly from the water, then it would take as much as 440 L of water to supply 1 gram (dry wt) of biofilm with the elements contained therein, assuming complete uptake. This seems especially unlikely in the case of Al, which is quite dilute (~500 ppb), poses very little benefit nutritionally, and increases in concentration down channel. Other major element components also exhibit at least one, if not all, of these traits. A potential source of the elements found in biofilms is aeolian-deposited dust. Area country rock is dominated by siliceous volcanism, represented locally by rhyolite samples collected from Sentinel Meadow. With an average value of ~10 wt % Al2O3 for the surrounding country rock, it would take approximately 0.6 grams of the ground up rock as dust to account for the Al found in one gram of biofilm. The low Al2O3 content of the sinter indicates that the Al is not entombed from the biofilms. A hypothesis for the above discrepancies in Al (as well as other elements) is that dust deposited in the water is captured on the biofilm surfaces, and the biofilm community then breaks down the dust, utilizing any nutritionally or metabolically important elements, and either precipitating (for Si) or releasing (for Al) unnecessary elements.

  18. BIOGEOCHEMISTRY OF THE RARE-EARTH ELEMENTS WITH PARTICULAR REFERENCE TO HICKORY TREES

    Microsoft Academic Search

    W. O. Robinson; H. Bastron; K. J. Murata

    1958-01-01

    Hickory trees concentrate the rare-earth elements in their leaves to a ; phenomenal degree and may contain as much as 2300 ppm of total rare earths based ; on the dry weight of the leaves. The average proportions of the individual ; elements (atomic percent of the total rareearth elements) in the leaves are: Y ; 36, La 16, Ce

  19. Determination of Major and Rare Earth Elements in Bastnasite Ores by ICP?AES

    Microsoft Academic Search

    Eftade O. Gaga; Aysun Do?angün; Semra G. Tuncel

    2004-01-01

    Analytical procedure for direct determination of La, Ce, Sm, Eu, Y, Yb, Pr, and Nd by ICP?AES in bastnasite ores without need for the initial separation or preconcentration of the rare earth elements (REEs), has been developed. Besides, rare earth elements, five major elements (Al, Ca, Ba, Fe, and Mg) were also measured. Two standard reference materials (GSP?2 and STM1

  20. Environmental geochemistry and ecological risk of vanadium pollution in Panzhihua mining and smelting area, Sichuan, China

    Microsoft Academic Search

    Yanguo Teng; Shijun Ni; Chengjiang Zhang; Jinsheng Wang; Xueyu Lin; Yi Huang

    2006-01-01

    Vanadium is a trace element widely distributed in the Earth’s crust. Naturally high levels of vanadium are recognized mainly\\u000a in basic rocks and minerals, particularly in titaniferous magnetite. And the anthropogenic sources of vanadium include fossil\\u000a fuel combustion and wastes including steel-industry slags. In the last few years, the authors have made investigations and\\u000a assessments on the environmental geochemistry and

  1. Aqueous geochemistry of the rare earth elements in marine anoxic basins

    Microsoft Academic Search

    J. Schijf

    1992-01-01

    Life in the oceans mainly occurs in the upper tens of meters of the watercolumn,\\u000awhere sunlight penetrates. This sunlight is used by phytoplankton to combine carbon and\\u000anutrients to organic matter, which subsequently serves zooplankton and higher life forms as\\u000afood. When the plankton dies it slowly settles to the seafloor, meanwhile being decomposed\\u000aby bacteria. This decomposition requires

  2. Sr isotope and rare earth element geochemistry of DSDP Leg 37 basalts

    Microsoft Academic Search

    R. K. O'Nions; R. J. Pankhurst

    1976-01-01

    87Sr\\/86Sr ratios have been determined on eleven whole rock basalt samples from DSDP Leg 37. The 87Sr\\/86Sr ratios range from 0.70305 +\\/- 4 to 0.70451 +\\/- 4 due to alteration and contamination with seawater Sr. Leaching with 5% HF has only a small effect on the 87Sr\\/86Sr of the samples. However, treatment with 6M HCl in acid digestion bombs at

  3. Rare earth element geochemistry of oceanic ferromanganese nodules and associated sediments

    Microsoft Academic Search

    H. Elderfield; C. J. Hawkesworth; M. J. Greaves; S. E. Calvert

    1981-01-01

    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

  4. The geochemistry of rare earth elements in groundwater from the Carnmenellis area, southwest England

    Microsoft Academic Search

    P SMEDLEY

    1991-01-01

    Shallow groundwater samples from the Carnmenellis area of southwest England collected from wells, boreholes, springs, adits and stream baseflow represent recently recharged waters of low salinity. Their major ion concentrations closely reflect the lithology of their host rocks which comprise the Carnmenellis granite and Devonian metasediments (and metabasite) of greenschist grade. Groundwaters from the granite are predominantly Na-Cl or Na-Ca-Cl

  5. Rapid separation of heavy rare-earth elements

    SciTech Connect

    Moore, B.W.; Froisland, I.J.; Petersen, A.E.

    1995-10-01

    The US Bureau of Mines investigated the separation of heavy rare-earth elements (REE) in an ion-exchange process. An ion-exchange column consisting of two sections, a loading section and a separation section, provides high levels of REE loading and good REE separation with an expected processing cycle of less than a month, while current ion-exchange technology requires more than 5 months. A different resin is used in each section: sulfonic resin in the loading section and iminodiacetic resin in the separation section. The separation section is further divided into two segments: the first conditioned with NH{sub 4} and the second with acid. Erbium is loaded onto both segments of the separation column as a retaining ion. Bands of mixed REE eluting between separated bands of pure REE were recycled directly to the column. Without mixed-band recycle, over 80% of the REE eluted from the column was separated into fractions with 99% purity of each element; with such recycle, the percentage of separated elements can be increased to around 90%.

  6. The chemistry of rare earth elements in the solar nebula

    NASA Technical Reports Server (NTRS)

    Larimer, J. W.; Bartholomay, H. A.; Fegley, B.

    1984-01-01

    The high concentration of rare earth elements (REE) in primitive CaS suggests that the REE along with the other normally lithophile elements form stable sulfides under the unusual conditions which existed during the formation of enstatite chrondites. In order to acquire a more quantitative framework in which to interpret these data, the behavior of the REE in systems with solar, or slightly fractionated solar, composition is being studied. These new data introduce modest changes in the behavior of some of the REE when compared to previous studies. For example, the largest differences are in the stabilities of the gaseous monoxides of Ce, Eu, Tb, Ho, and Tm, all of which now appear to be less stable than previously thought, and YbO(g) which is somewhat more stable. Much more significant are the changes in REE distribution in the gas phase in fractionated systems, especially those made more reducing by changing the C/O ratio from the solar value of 0.6 to about 1.0. In almost all cases, the exceptions being Eu, Tm and Yb whose elemental gaseous species dominate, the monosulfides become more abundant. Moreover, the solid oxides of Eu, Tm and Yb become less stable under more reducing conditions which, in effect, should reduce the condensation temperature of all REE in more reduced systems.

  7. Major, trace element and stable isotope geochemistry of synorogenic breccia bodies, Ellsworth Mountains, Antarctica

    USGS Publications Warehouse

    Craddock, J.P.; McGillion, M.S.; Webers, G.F.

    2007-01-01

    Cambrian carbonates in the Heritage Range of the Ellsworth Mountains, West Antarctica host a series of carbonate-rich breccia bodies that formed contemporaneously with the Permian Gondwanide orogen. The breccia bodies had a three-stage genesis, with the older breccias containing Cambrian limestone (and marble) clasts supported by calcite, whereas the younger breccias are nearly clast-free and composed entirely of matrix calcite. Breccia clasts, calcite matrix and detrital matrix samples were analyzed using x-ray fluorescence (major and trace elements), x-ray diffraction, and stable isotopes (C, O) and suggest that the breccias formed as part of a closed geochemical system, at considerable depth, within the Cambrian limestone host as the Ellsworth Mountains deformed into a fold-and-thrust belt along the margin of Gondwana

  8. Trace element geochemistry of coals from the Southern Cantabrian Zone (NW Spain): preliminary results

    NASA Astrophysics Data System (ADS)

    Botor, Dariusz

    2011-01-01

    Bituminous to anthracite coals from three small Stephanian intramontane coal-bearing basins (La Magdalena, Cinera-Matallana and Sabero) located along the Sabero-Gordón fault line strike-slip systems of the Southern Cantabrian Zone (SCZ) were examined. Coal rank expressed as mean vitrinite reflectance values of these Stephanian coals is in the range 0.72-3.96%. The vitrinite maceral group exceeds 72 vol. % in all of the coals. The coals are characterized by relatively variable contents of mineral matter and coal-ash. The mineral matter comprises, in the main, clay minerals, carbonates, sulphides and quartz. The coals exhibit medium-high concentrations (see for comparison Ronov et al. 1990; Kabata-Pendias, Pendias 1999; Ketris, Yudovich 2009) of the following elements (in ppm): ?REE (53-205), Ba (300-900), As (11-57), Zn (<50-150), Cr (10-160), Rb (50-145), Co (5-26), Sc (2-24.6), Ce (17-99), Yb (1.3-4.5), Th (2.4-11.9) and U (1.1-8.1), Br (<1-14), Cs (<2-9), Eu (<0,3-1.5), Lu (0.11-0.85) and Sb (0.8-4.8), and relatively low concentrations of Sm (0.6-6.6) and Ta (<1-2). They are also characterised by relatively high Th/U values (1.31-2.29). LREE/HREE values fall in the range 24-44 (average - 30). In contrast, concentrations of Au, Ag, Hg, Ir, Ni, Se, Sn, Sr, and W are below detection limits for the applied INAA method. As the concentrations of elements are significantly higher in coal-ash, most are likely related to mineral matter in the coals.

  9. Biogeochemistry of the rare-earth elements with particular reference to hickory trees

    Microsoft Academic Search

    W. O. Robinson; H. Bastron; K. J. Murata

    1958-01-01

    Hickory trees concentrate the rare-earth elements in their leaves to a phenomenal degree and may contain as much as 2300 p.p.m. of total rare earths based on the dry weight of the leaves. The average proportions of the individual elements (atomic percent of the total rare-earth elements) in the leaves are: Y 36, La 16, Ce 14, Pr 2, Nd

  10. [Physiological effects of rare earth elements and their application in traditional Chinese medicine].

    PubMed

    Zhou, Jie; Guo, Lanping; Xiao, Wenjuan; Geng, Yanling; Wang, Xiao; Shi, Xin'gang; Dan, Staerk

    2012-08-01

    The process in the studies on physiological effects of rare earth elements in plants and their action mechanisms were summarized in the aspects of seed germination, photosynthesis, mineral metabolism and stress resistance. And the applications of rare earth elements in traditional Chinese medicine (TCM) in recent years were also overviewed, which will provide reference for further development and application of rare earth elements in TCM. PMID:23189726

  11. Rare earth elements activate endocytosis in plant cells.

    PubMed

    Wang, Lihong; Li, Jigang; Zhou, Qing; Yang, Guangmei; Ding, Xiao Lan; Li, Xiaodong; Cai, Chen Xin; Zhang, Zhao; Wei, Hai Yan; Lu, Tian Hong; Deng, Xing Wang; Huang, Xiao Hua

    2014-09-01

    It has long been observed that rare earth elements (REEs) regulate multiple facets of plant growth and development. However, the underlying mechanisms remain largely unclear. Here, using electron microscopic autoradiography, we show the life cycle of a light REE (lanthanum) and a heavy REE (terbium) in horseradish leaf cells. Our data indicate that REEs were first anchored on the plasma membrane in the form of nanoscale particles, and then entered the cells by endocytosis. Consistently, REEs activated endocytosis in plant cells, which may be the cellular basis of REE actions in plants. Moreover, we discovered that a portion of REEs was successively released into the cytoplasm, self-assembled to form nanoscale clusters, and finally deposited in horseradish leaf cells. Taken together, our data reveal the life cycle of REEs and their cellular behaviors in plant cells, which shed light on the cellular mechanisms of REE actions in living organisms. PMID:25114214

  12. Microbial Paleontology, Mineralogy and Geochemistry of Modern and Ancient Thermal Spring Deposits and Their Recognition on the Early Earth and Mars"

    NASA Technical Reports Server (NTRS)

    Farmer, Jack D.

    2004-01-01

    The vision of this project was to improve our understanding of the processes by which microbiological information is captured and preserved in rapidly mineralizing sedimentary environments. Specifically, the research focused on the ways in which microbial mats and biofilms influence the sedimentology, geochemistry and paleontology of modem hydrothermal spring deposits in Yellowstone national Park and their ancient analogs. Toward that goal, we sought to understand how the preservation of fossil biosignatures is affected by 1) taphonomy- the natural degradation processes that affect an organism from the time of its death, until its discovery as a fossil and 2) diagenesis- longer-term, post-depositional processes, including cementation and matrix recrystallization, which collectively affect the mineral matrix that contains fossil biosignature information. Early objectives of this project included the development of observational frameworks (facies models) and methods (highly-integrated, interdisciplinary approaches) that could be used to explore for hydrothermal deposits in ancient terranes on Earth, and eventually on Mars.

  13. 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. PMID:18639916

  14. Rare Earth elements in individual minerals in Shergottites

    NASA Technical Reports Server (NTRS)

    Wadhwa, Meenakshi; Crozaz, Ghislaine

    1993-01-01

    Shergottites (i.e., Shergotty, Zagami, EETA79001, ALHA77005, and LEW88516) are an important set of achondrites because they comprise the majority of the SNC group of meteorites (nine, in total, known to us), which are likely to be samples of the planet Mars. Study of these meteorites may therefore provide valuable information about petrogenetic processes on a large planetary body other than Earth. Rare earth element (REE) distributions between various mineral phases were found to be useful in geochemically modeling the petrogenesis of various rock types (terrestrial and meteoritic). However, with the exception of a few ion microprobe studies and analyses of mineral separates, there has previously not been any comprehensive effort to characterize and directly compare REE in individual minerals in each of the five known shergottites. Ion microprobe analyses were made on thin sections of each of the shergottites. Minerals analyzed were pyroxenes (pigeonite and augite), maskelynite, and whitlockite. The REE concentrations in each mineral type in each shergottite is given.

  15. Mineralogy, petrology, and trace element geochemistry of the Johnstown meteorite - A brecciated orthopyroxenite with siderophile and REE-rich components

    NASA Technical Reports Server (NTRS)

    Floran, R. J.; Prinz, M.; Hlava, P. F.; Keil, K.; Spettel, B.; Waenke, H.

    1981-01-01

    The compositional and petrologic characteristics of the Johnstown meteorite show it to contain uncontaminated and unbrecciated orthopyroxenite clasts of cumulative origin that (1) must have undergone subsolidus recrystalization, (2) are parental to the brecciated matrix, and (3) show no evidence of a xenolithic, meteoritic contribution to the matrix except for contamination by the projectile which crushed it on impact. The trapped liquid was not introduced in the impact process. The variability of such trace elements as the light rare earth elements, and the presence of plagioclase and olivine in only one of the thin sections studied, demonstrates the heterogeneity of coarse-grained diogenites on a millimeter scale and the difficulty of obtaining representative samples of such meteorites. The data presented indicate that this meteorite is a monominct breccia.

  16. Separation of rare earth elements with high-speed countercurrent chromatography

    SciTech Connect

    Kitazome, E.; Ito, Y.; Ficca, S.

    1990-02-28

    The invention relates to continuous countercurrent chromatography, and more particularly relates to methods for continuous countercurrent chromatography separation and detection of rare earth elements and compounds.

  17. Deciphering The Sources Of Cenozoic Volcanism In Central Mongolia Using Trace Element And Isotope Geochemistry

    NASA Astrophysics Data System (ADS)

    Hunt, A. C.; Parkinson, I. J.; Harris, N.; Rogers, N. W.; Barry, T.; Yondon, M.

    2009-12-01

    One of the largest regions of Cenozoic intra-plate volcanism stretches across central Asia from the Baikal Rift in Siberia, through central Mongolia to China. In Mongolia this is expressed as numerous small-volume alkali-basaltic cones and lavas, erupted since ca. 30 Ma. Currently, accepted models of melt generation for intraplate magmatism, such as mantle plumes, lithospheric extension and convective removal of the lithosphere, are difficult to reconcile with some aspects of volcanism and tectonics in this region. A suite of basalts erupted across an area of Cenozoic uplift in central Mongolia, known as the Hangai Dome, has been analysed for trace elements and Sr-Nd-Pb isotopes. New Pb isotope data were collected by double spike MC-ICP-MS at the Open University and have a long-term 2? reproducibility better than 175 ppm for NBS 981. These data suggest progressive mixing between two distinct source regions in the genesis of the Hangai basalts. Older basalts, previously dated at 5.91 ± 0.02 Ma (Barry et al., 2003), are derived from a component with an asthenospheric signature similar to depleted Indian MORB. Younger basalts are increasingly mixed with a component with lower Pb and Sr ratios and an enriched trace element signature, which is similar in composition to some lamproites erupted in the western USA (Mirnejad and Bell, 2006). This represents a transition from asthenospheric to lithospheric melting through time. Furthermore, studies on mantle xenoliths from across the Hangai Dome indicate an elevated geotherm under the centre of the dome and significantly cooler conditions at its margins, interpreted to be the result of mantle upwellling (Harris et al., in review). Further numerical modelling will assess the relative contributions from lithospheric and asthenospheric sources in the genesis of these basalts, and contribute to understanding this enigmatic volcanic region. Barry, T. L., Saunders, A. D., Kempton, P. D., Windley, B.F., Pringle, M.S., Dorjnamjaa, D. and Saander, S. (2003)., J. Petrol. 44 55-91 Harris, N., Hunt, A., Parkinson, I., Tindle, A., Yondon, M. and Hammond, S. (2009) in review Mirnejad, H. And Bell, K (2006)., J. Petrol. 47 2463-2489

  18. EARTH’S CORE FORMATION: NEW CONSTRAINTS FROM SIDEROPHILE ELEMENTS PARTITIONING (Invited)

    NASA Astrophysics Data System (ADS)

    Siebert, J.; Corgne, A.; Ryerson, F. J.

    2009-12-01

    The abundances of siderophile elements in the Earth’s mantle are the result of core formation in the early Earth. Many variables are involved in the prediction of metal/silicate siderophile partition coefficients during core segregation: pressure, temperature, oxygen fugacity, silicate and metal compositions. Despite publications of numerous results of metal-silicate experiments, the experimental database and predictive expressions for elements partitioning are hampered by a lack of systematic study to separate and evaluate the effects of each variable. Only a relatively complete experimental database that describes Ni and Co partitioning now exists but is not sufficient to unambiguously decide between the most popular model for core formation with a single stage core-mantle equilibration at the bottom of a deep magma ocean (e.g. Li and Agee, 2001) and more recent alternative models (e.g. Wade and Wood, 2005; Rubie et al., 2007). In this experimental work, systematic study of metal-silicate partitioning is presented for elements normally regarded as moderately siderophile (Mo, As, Ge, W, P, Ni, Co), slightly siderophile (Zn, Ga, Mn, V, Cr) and refractory lithophile (Nb, Ta). New results are obtained for elements whose partitioning behavior is usually poorly constrained and not integrated into any accretion or core formation models. A new piston-cylinder design assembly allows us to present a suite of isobaric partitioning experiments at 3 GPa within a temperature range from 1600 to 2600 C and over a range of relative oxygen fugacity from IW-1.5 to IW-3.5. Silicate melts range from basaltic to peridotite in composition. The individual effect of pressure is also investigated through a combination of piston cylinder and multi anvil isothermal experiments from 0.5 to 18 GPa at 1900 C. Absolute measurements of partitioning coefficients combining EMP and LA-ICPMS analytical methods are provided. Moreover, thermodynamic calculations were performed to assess the effects of light elements (S, Si, C, O) dissolved in the segregating core on partitioning behaviors. We will discuss the implications of partitioning data collected in this study for proposed single-stage and continuous core formation models.

  19. Crystal Field Effects and Siderophile Element Partitioning: Implications for Mars HSE Geochemistry

    NASA Technical Reports Server (NTRS)

    Jones, John H.; Malavergne, V.; Neal, C. R.

    2007-01-01

    Analyses of martian (SNC) meteorites indicate that Pt abundances do not vary much compared to other highly siderophile elements (HSE). Therefore, Jones et al. [1] inferred that D(Pt) during basalt petrogenesis was of order unity. This inference was at odds with previously published experiments that gave a D(sub ol/liq) for Pt of approx. 0.01 [2]. Because olivine is likely to be an important constituent of any reasonable martian mantle, the implication of these findings is that minor minerals must have D(Pt) much greater than 1, which seemed improbable. However, not only did the SNC evidence point to a D(sub ol/liq) approx. equal to 1, but so did plots of D(sub ol/liq) vs. ionic radius (Onuma diagram). The ionic radius of Pt(2+) suggested that D(sub ol/liq) for Pt was of order unity, in agreement with the inferences from SNC meteorites. New experiments have failed to detect measurable Pt in olivine, even at high oxygen fugacities [3]. Therefore, some other parameter, other than ionic charge and radius, must hold sway during olivine liquid partitioning of Pt.

  20. Geochemistry of arsenic and other trace elements in a volcanic aquifer system of Kumamoto Area, Japan

    NASA Astrophysics Data System (ADS)

    Hossain, Shahadat; Hosono, Takahiro; Shimada, Jun

    2015-04-01

    Total arsenic (As), As(III) species, dissolved organic carbon (DOC), methane (CH4), sulfur isotope ratios of sulfate (?34SSO4), major ions and trace elements were measured in groundwater collected from boreholes and wells along the flow lines of western margins of Kumamoto basin, at central part of Kyushu island in southern Japan. Kumamoto city is considered as the largest groundwater city in Japan. 100% people of this city depends on groundwater for their drinking purpose. In this study, we used trace elements data and ?34SSO4 values to better understand the processes that are likely controlling mobilization of As in this area. Arsenic concentrations ranges from 1 to 60.6 ?g/L. High concentrations were found in both shallow and deep aquifers. The aquifers are composed of Quaternary volcanic (pyroclastic) flow deposits. In both aquifers, groundwaters evolve along the down flow gradient from oxidizing conditions of recharge area to the reducing conditions of stagnant area of Kumamoto plain. 40% samples from the Kumamoto plain area excced the maximum permissible limit of Japan drinking water quality standard (10 ?g/L). In the reducing groundwater, As(III) constitutes typically more, however; 50% samples dominated with As(III) and 50% samples dominated with As(V) species. High As concentrations occur in anaerobic stagnant groundwaters from this plain area with high dissolved Fe, Mn, moderately dissolved HCO3, PO4, DOC and with very low concentrations of NO3 and SO4 suggesting the reducing condition of subsurface aquifer. Moderately positive correlation between As and dissolved Fe, Mn and strong negative correlation between As(III)/As(V) ratio and V, Cr and U reflect the dependence of As concentration on the reductive process. The wide range of ?34SSO4 values (6.8 to 36.1‰) indicate that sulfur is undergoing redox cycling. Highly enriched values suggesting the process was probably mediated by microbial activity. It also be noted from positive values of sulfur isotopes that sulfate was not originated from oxidation process of pyrite. A weak correlation was observed between ?34SSO4 values and total As contents when all the samples were considered. Although, there is evidence for sulfate reduction, however; it is less clear about co-pricipitation or sequester of As with Fe and Sulfide ion. It is evident that As distribution in subsurface geological media is not controlled by single solid phase. Probably, dissolution-desorption from different phases contributes to the total As in groundwater. The data are consistant with the possibility that microbial mediated reactions and reductive dessolution of Fe-oxyhydroxides are the important processes to mobilize arsenic in this area. The combination of slow flow of groundwater and the younger age of aquifer sediments are also considered potentially important causes for the high dissolved As concentrations in groundwater as the sediments have not been well flushed since burial.

  1. Rare earth element fractionation in magmatic Ca-rich garnets

    NASA Astrophysics Data System (ADS)

    Scheibner, Birgit; Wörner, Gerhard; Civetta, Lucia; Stosch, Heinz-Günter; Simon, Klaus; Kronz, Andreas

    2007-07-01

    Igneous garnets have the potential to strongly fractionate rare earth elements (REE). Yet informations on partition coefficients are very scant, and criteria for distinguishing between hydrothermal and magmatic garnets are ambiguous. To fill this gap, we present trace element and isotopic data for two types of Ca-rich garnets from phonolites (Mt. Somma-Vesuvius). Both Ca-garnet populations are different in their style and dynamics of fractionation: one population is progressively strongly depleted in HREE from core to rim, reflecting REE fractionation in the host phonolite via earlier-crystallized garnets. Such examples for extreme changes in HREE in garnets are only known for hydrothermal grandites by REE-bearing fluids. The second garnet population is homogeneous and formed in a closed system. Near-flat patterns between Sm and Lu confirm experimental data indicating lower D(Sm)/ D(Lu) for Ca-rich garnets than for e.g. pyrope-rich garnets. It follows: D Grt/PhMelt for La = 0.5, Sm = 48 and Yb = 110.

  2. Rare earth element analysis indicates micropollutants in an urban estuary

    NASA Astrophysics Data System (ADS)

    Mohajerin, T. J.; Johannesson, K. H.; Kolker, A.; Burdige, D. J.; Chevis, D.

    2011-12-01

    Rare earth element analysis of Bayou Bienvenue waters shows anomalously high gadolinium, Gd, concentrations relative to its nearest neighbors in the REE series, europium and terbium. The anomalously high Gd concentrations indicate anthropogenic input from waste-water treatment plants in the area as anthropogenic Gd input can be traced back to its use as a contrast agent in magnetic resonance imaging in hospitals. Others have shown that anomalously high levels of Gd in natural waters are likely to be associated with other micropollutants that also occur in hospital effluent and that are not removed in the wastewater treatment process, including pharmaceuticals in the form of steroids, antihistamines, and antibiotics. Estuaries serve as many important ecological roles and have been shown to act as a filter for pollutants. To better understand the transport, biogeochemical cycling, and ultimate fate of trace elements in estuaries, I collected surface water samples from Bayou Bienvenue, a wetland triangle that covers an area of 427 acres directly adjacent to New Orleans, Louisiana. Water samples from Bayou Bienvenue were collected along the salinity gradient and subsequently filtered through progressively smaller pore-size filters. The resulting fractions were analyzed for trace element concentions, including the REEs, by magnetic sector ICP-MS. The attached figure shows the Gd anomaly present in the particulate (>0.45?m) fraction. Upper continental crust (UCC)-normalized plots of colloidal REEs (0.02?m - 0.45?m) fraction is lacking this anomaly indicating anthropogenic Gd is found chiefly in the particulate fraction in Bayou Bienvenue. No clear relationship between Gd concentration and salinity was apparent.

  3. Rare Earth Elements reveal past earthquakes on limestone normal faults

    NASA Astrophysics Data System (ADS)

    Manighetti, I.; Boucher, E.; Chauvel, C.; Schlagenhauf, A.; Benedetti, L.

    2009-12-01

    In 2008, we suggested that the chemical composition of the rocks which form well preserved, seismically exhumed fault scarps might record past major earthquakes (Carcaillet et al., 2008) because those scarp surfaces consist of a vertical succession of zones that have been exposed at different times by the repeating earthquakes, thus weathered over different time spans. In this pioneer study, we validated this hypothesis using the changes in chemical compositions (major and trace elements) of 15 carbonate rock samples collected from the base to the top of the seismically exhumed, 10 m-high Magnola normal fault scarp (Abruzzes, Central Italy). However, the number of available samples was insufficient to fully assess the validity of the model. Here we present trace element data on 27 additional samples collected systematically every 25 cm along the Magnola scarp, as well as on 7 scarp samples buried below the colluvium hence representing the first 4 meters of the scarp before exhumation. The scarp rocks buried in the first meter of the ground appear significantly enriched in Rare Earth elements (REE): they contain 60% more REE than the rocks located either deeper in the ground or immediately above the ground level. This concentration peak most probably results from enrichment of the scarp rocks by interaction with the impurity-doped, acidic, upper soil. Above the ground surface and along the scarp, most element concentrations (70%) decrease up-dip, generally by more than 50%; we attribute this trend to leaching and dissolution-recrystallization of purer calcite through time. The top of the scarp having been exposed for a longer period of time, its surface lost more of the trace elements contained in the rocks. However, the upward decrease in REE contents is not linear and 4 REE concentration peaks can be recognized along the exposed scarp. The position of these 4 peaks coincide with the zones identified by Schlagenhauf et al. (2009) and Palumbo et al. (2004) as separating the major earthquake ruptures that produced the scarp exhumation (the identification was independently performed using cosmogenic 36Cl modeling). This finding confirms that the REE concentration peaks are excellent indicators of the position of paleo-ground levels and good markers for the large earthquake ruptures that created the exhumation. We thus conclude that simple REE chemical analyses of seismically exhumed fault scarp rocks may be used to identify past major earthquakes. They also allow the measurement of the vertical slip produced by the earthquakes along the fault. This simple novel approach is thus very promising to recover seismic histories on active faults.

  4. ON THE SEPARATION OF RARE EARTH ELEMENTS. VI. FURTHER STUDY OF RARE EARTH ELEMENT SEPARATION BY COMPLEX ELUTION. METHOD OF RAPID LANTHANUM SEPARATION

    Microsoft Academic Search

    Massonne

    1958-01-01

    Lanthanum was separated from a mixture of rare earth elements by ion ; exchange. All the nare earths, with the exception of lanthanum, were eluted from ; the resin with a 4% solution of beta -oxyethyliminodiacetic acid at pH 5 and a ; temperature of 70 icient laborato C. The lanthanum was then eluted with a 4% ; nitryltriacetic acid

  5. Carbon and other light element contents in the Earth’s core based on first-principles molecular dynamics

    PubMed Central

    Zhang, Yigang; Yin, Qing-Zhu

    2012-01-01

    Carbon (C) is one of the candidate light elements proposed to account for the density deficit of the Earth’s core. In addition, C significantly affects siderophile and chalcophile element partitioning between metal and silicate and thus the distribution of these elements in the Earth’s core and mantle. Derivation of the accretion and core–mantle segregation history of the Earth requires, therefore, an accurate knowledge of the C abundance in the Earth’s core. Previous estimates of the C content of the core differ by a factor of ?20 due to differences in assumptions and methods, and because the metal–silicate partition coefficient of C was previously unknown. Here we use two-phase first-principles molecular dynamics to derive this partition coefficient of C between liquid iron and silicate melt. We calculate a value of 9 ± 3 at 3,200 K and 40 GPa. Using this partition coefficient and the most recent estimates of bulk Earth or mantle C contents, we infer that the Earth’s core contains 0.1–0.7 wt% of C. Carbon thus plays a moderate role in the density deficit of the core and in the distribution of siderophile and chalcophile elements during core–mantle segregation processes. The partition coefficients of nitrogen (N), hydrogen, helium, phosphorus, magnesium, oxygen, and silicon are also inferred and found to be in close agreement with experiments and other geochemical constraints. Contents of these elements in the core derived from applying these partition coefficients match those derived by using the cosmochemical volatility curve and geochemical mass balance arguments. N is an exception, indicating its retention in a mantle phase instead of in the core. PMID:23150591

  6. Aspects of the early sulfur cycle and its effects on the climate and geochemistry of Earth and Mars

    NASA Astrophysics Data System (ADS)

    Halevy, Itay

    Planetary climate and surface chemistry are tightly coupled; atmospheric composition affects the transfer of solar and infrared radiation, and therefore climate, whereas the components of climate, including temperature and precipitation, strongly affect the chemical composition of the surface environment and the geochemical cycling of elements through it. An element of climatic, environmental and biological importance is sulfur. The modern biogeochemical sulfur cycle has been extensively studied and is relatively well understood. How the sulfur cycle may have differed early in the evolution of Earth and Mars, when the surface was anoxic and biological activity was geochemically unimportant, is less well understood and much more poorly constrained by data. In this PhD thesis we explore the early sulfur cycle using theory, experiments and models, emphasizing the differences from the modern and the implications for climate and the surface environment. On early Mars, we propose that the combination of a thick CO2 atmosphere and vigorous volcanic outgassing, may have allowed SO2 to accumulate to climatic importance. Developing and using a line-by-line radiative transfer model, we show that the radiative forcing supplied by a thick CO2 greenhouse is uncertain but that part-per-million concentrations of SO2 provide appreciable additional warming, perhaps enough to explain the early action of liquid water. In addition, SO2 may explain the observed Martian mineralogical record, winch contains abundant early sulfate, but no carbonate minerals. We show experimentally that sulfite minerals precipitate at the expense of carbonates at ratios of SO2 to CO2 as low as a few parts-per-billion, and that the sulfites transform to sulfates when exposed to oxidizing conditions. In contrast, rapid aqueous-phase destruction of SO2 probably kept its concentration in Earth's early ocean much too low to matter climatically or mineralogically. Even so, with a simple model of the early Archean ocean-atmosphere we show that the record of mass-independent sulfur isotope fractionation can only be quantitatively interpreted by considering a full, anoxic sulfur cycle, and that such treatment provides explanations for salient features in this record. Finally, we present a coupled atmosphere-surface model, to be used for a detailed investigation of the sulfur cycle.

  7. Rare earth elements exploitation, geopolitical implications and raw materials trading

    NASA Astrophysics Data System (ADS)

    Chemin, Marie-Charlotte

    2015-04-01

    Rare earth elements (REE) correspond to seventeen elements of the periodic table. They are used in high technology, cracking, electric cars' magnet, metal alloy for batteries, and also in phone construction or ceramics for electronic card. REEs are an important resource for high technology. This project targets 16 years old students in the subject "personalized aid" and will last six weeks. The purpose of this project is to develop autonomy and research in groups for a transdisciplinary work. This project gathers knowledge in geology, geography and economics. During the first session students analyze the geology applications of the REE. They begin the analysis with learning the composition in different rocks such as basalt and diorite to make the link with crystallization. Then they compare it with adakite to understand the formation of these rocks. In the second session, they study REE exploitation. We can find them as oxides in many deposits. The principal concentrations of rare earth elements are associated with uncommon varieties of igneous rocks, such as carbonatites. They can use Qgis, to localize this high concentration. In the third session, they study the environmental costs of REE exploitation. Indeed, the exploitation produces thorium and carcinogenic toxins: sulphates, ammonia and hydrochloric acid. Processing one ton of rare earths produces 2,000 tons of toxic waste. This session focuses, first, on Baotou's region, and then on an example they are free to choose. In the fourth session, they study the geopolitical issues of REE with a focus on China. In fact this country is the largest producer of REE, and is providing 95% of the overall production. REE in China are at the center of a geopolitical strategy. In fact, China implements a sort of protectionism. Indeed, the export tax on REE is very high so, as a foreign company, it is financially attractive to establish a manufacturing subsidiary in China in order to use REE. As a matter of fact, establishing a company in China can lower the production cost (since the company buys the products used in its production at a lower price). In the fifth session, they study the raw materials trading based on the futures contracts example. A producer, to avoid a rise in prices of raw materials used in his production can use derivative products on the financial market: futures contracts for instance. This product ensures a quantity and quality for a price and a delivery date agreed upon today. Actually, producers can use a method called Fix price hedging in order to fix the price of a specific product. The main idea is to balance out the "physical position" (spot market) and the "paper position" (futures market). Even if the REE are commercialized in form of a non-perishable's oxide, the flow of the stock must be guaranteed and this is why it is important for producers to secure their supply of raw materials. In the last session, students search local companies that use REE in their production process and study their strategy on the market.

  8. Rare earth elements in scleractinian cold-water corals

    NASA Astrophysics Data System (ADS)

    Raddatz, J.; Liebetrau, V.; Hathorne, E. C.; Rüggeberg, A.; Dullo, W.; Frank, M.

    2012-12-01

    The Rare Earth Elements (REE) have a great potential to trace continental input, particle scavenging and the oxidation state of seawater. These REE are recorded in the skeleton of the cosmopolitan cold-water corals Lophelia pertusa. Here we use an online preconcentration ICP-MS method (Hathorne et al. 2012) to measure REE concentrations in seawater and associated cold-water coral carbonates in order to investigate their seawater origin. Scleractinian cold-water corals were collected in-situ and alive and with corresponding seawater samples covering from the European Continental Margin. The seawater REE patterns are characterized by the typical negative cerium anomaly of seawater, but are distinct for the northern Norwegian Margin and the Oslo Fjord, probably related to continental input. Initial results for the corresponding coral samples suggest that these distinct REE patterns of ambient seawater are recorded by the coral skeletons although some fractionation during incorporation into the aragonite occurs. This indicates that scleractinian cold-water corals can serve as a valuable archive for seawater derived REE signatures, as well radiogenic Nd isotope compositions. In a second step we analysed fossil coral samples from various locations, which were oxidatively and reductively cleaned prior to analysis. Initial results reveal that sediment-buried fossil (early Pleistocene to Holocene) coral samples from the Norwegian Margin and the Porcupine Seabight (Challenger Mound, IODP Site 1317) do not show the expected seawater REE patterns. In particular, the fossil coral-derived REE patterns lack a negative cerium anomaly suggesting that fossil coral-REE patterns do not represent ambient seawater. Thus, we suggest that the oxidative-reductive cleaning method widely used for cleaning of marine carbonates such as foraminifera prior to measurements of seawater-derived trace metal and isotope compositions are not sufficient for REE and Nd isotopes in sediment-buried coral-water corals and require alternative or additional approaches. Hathorne, E.C., B. Haley, T. Stichel, P. Grasse, M. Zieringer, and M. Frank (2012). Online preconcentration ICP-MS analysis of rare earth elements in seawater, Geochem. Geophys. Geosyst.,13, Q01020, doi:10.1029/2011GC003907. .

  9. NREL Highlights SCIENCE These polycrystalline cells use Earth-abundant elements.

    E-print Network

    an 8.4%-efficient CZTSe solar cell produced using commercially acceptable manufacturing techniquesNREL Highlights SCIENCE These polycrystalline cells use Earth-abundant elements. NREL scientists (CZTSe) solar cells, which are based on non-toxic, Earth-abundant elements. Recently, NREL demonstrated

  10. Principles of the extraction of rare earth elements with naphthenic acids

    Microsoft Academic Search

    G. V. Korpusov; N. A. Danilov; V. Ya. Shvartsman; Yu. S. Krylov

    1975-01-01

    The composition of the extractable lanthanum compounds with the individual naphthenic acid CââHââOâ was determined. The influence of the concentration of nitrates and chlorides of the rare earth elements, as well as salting out agents, on the values of the coefficients of separation of the rare earth elements by naphthenic acids, isolated from petroleum fractions and from stratum waters, was

  11. RARE EARTH ELEMENTS AFFECTING THE BIOLOGICAL PROCESSES AND YIELDING ABILITIES OF CULTIVATED CROPS

    Microsoft Academic Search

    Rare earth elements affecting the biological processes and yielding abilities of cultivated crops. The research work was conducted at the Estonian Research Institute of Agriculture in 1997-2002. For the trials a high- concentration original solution of rare earth elements (REE), resulting from the production process of AS Silmet, was used. REE solutions of different concentrations were used to treat the

  12. Special glassy materials doped with rare-earth elements for fiber optics

    Microsoft Academic Search

    Jan Wasylak; Dominik Dorosz; Jan Kucharski; Jan Kityk

    2003-01-01

    Lead-bismuth-gallium-cadmium glasses doped with rare earths elements have been investigated. Certain optical properties of the glasses have been determined. The results of luminescence investiations in the form of absorption and luminescence spectra are presented, and the quantum yields as well as the calculated and measured luminescence lifetimes of the particular rare earths elements in the matrix of the examined glasses

  13. Physiological and Biochemical Effects of Rare Earth Elements on Plants and Their Agricultural Significance: A Review

    Microsoft Academic Search

    Zhengyi Hu; Herfried Richter; Gerd Sparovek; Ewald Schnug

    2004-01-01

    The rare earths include the elements scandium [Sc, atomic number (Z) = 21], yttrium (Y, Z = 39), and the lanthanides from lanthanum (La, Z = 57) to lutetium (Lu, Z = 71). Crop responses to application of rare earth elements (REEs) have only been documented in a few countries. The reasons for promoting growth or yield increases are still not sufficiently understood. Recently, physiological interaction of REEs

  14. Carbonatite and alkaline intrusion-related rare earth element deposits–A deposit model

    USGS Publications Warehouse

    Verplanck, Philip L.; Van Gosen, Bradley S.

    2011-01-01

    The rare earth elements are not as rare in nature as their name implies, but economic deposits with these elements are not common and few deposits have been large producers. In the past 25 years, demand for rare earth elements has increased dramatically because of their wide and diverse use in high-technology applications. Yet, presently the global production and supply of rare earth elements come from only a few sources. China produces more than 95 percent of the world's supply of rare earth elements. Because of China's decision to restrict exports of these elements, the price of rare earth elements has increased and industrial countries are concerned about supply shortages. As a result, understanding the distribution and origin of rare earth elements deposits, and identifying and quantifying our nation's rare earth elements resources have become priorities. Carbonatite and alkaline intrusive complexes, as well as their weathering products, are the primary sources of rare earth elements. The general mineral deposit model summarized here is part of an effort by the U.S. Geological Survey's Mineral Resources Program to update existing models and develop new descriptive mineral deposit models to supplement previously published models for use in mineral-resource and mineral-environmental assessments. Carbonatite and alkaline intrusion-related REE deposits are discussed together because of their spatial association, common enrichment in incompatible elements, and similarities in genesis. A wide variety of commodities have been exploited from carbonatites and alkaline igneous rocks, such as rare earth elements, niobium, phosphate, titanium, vermiculite, barite, fluorite, copper, calcite, and zirconium. Other enrichments include manganese, strontium, tantalum, thorium, vanadium, and uranium.

  15. Geochemistry of ultrahigh-pressure anatexis: fractionation of elements in the Kokchetav gneisses during melting at diamond-facies conditions

    NASA Astrophysics Data System (ADS)

    Stepanov, Aleksandr S.; Hermann, Joerg; Korsakov, Andrey V.; Rubatto, Daniela

    2014-05-01

    The Kokchetav complex in Kazakhstan contains garnet-bearing gneisses that formed by partial melting of metasedimentary rocks at ultrahigh-pressure (UHP) conditions. Partial melting and melt extraction from these rocks is documented by a decrease in K2O and an increase in FeO + MgO in the restites. The most characteristic trace element feature of the Kokchetav UHP restites is a strong depletion in light rare earth elements (LREE), Th and U. This is attributed to complete dissolution of monazite/allanite in the melt and variable degree of melt extraction. In contrast, Zr concentrations remain approximately constant in all gneisses. Using experimentally determined solubilities of LREE and Zr in high-pressure melts, these data constrain the temperature of melting to ~1,000 °C. Large ion lithophile elements (LILE) are only moderately depleted in the samples that have the lowest U, Th and LREE contents, indicating that phengite retains some LILE in the residue. Some restites display an increase in Nb/Ta with respect to the protolith. This further suggests the presence of phengite, which, in contrast to rutile, preferentially incorporates Nb over Ta. The trace element fractionation observed during UHP anatexis in the Kokchetav gneisses is significantly different from depletions reported in low-pressure restites, where generally no LREE and Th depletion occurs. Melting at UHP conditions resulted in an increase in the Sm/Nd ratio and a decoupling of the Sm-Nd and Lu-Hf systems in the restite. Further subduction of such restites and mixing with mantle rocks might thus lead to a distinct isotopic reservoir different from the bulk continental crust.

  16. Dihydrated and anhydrous fluoride oxalates of rare-earth elements

    SciTech Connect

    Pushkina, G.Ya.; Arkhangel'skii, I.V.; Kizhlo, M.R.; Komissarova, L.N.; Shatskii, V.M.

    1987-11-01

    The conditions for the synthesis of crystal dihydrates and anhydrous fluoride oxalates of the rare-earth elements of the yttrium subgroup (Tb-Lu and Y) with the general formulas LnC/sub 2/O/sub 4/F x 2H/sub 2/O and LnC/sub 2/O/sub 4/F have been worked out. Crystalline forms of LnC/sub 2/O/sub 4/F appear when LnC/sub 2/O/sub 4/F x nH/sub 2/O (n = 2, 4) are dehydrated in autoclaves (50 atm, 220/sup 0/C) and sealed ampuls (10 atm, 270/sup 0/C), and the dehydrates are obtained as a result of the dehydration of LnC/sub 2/O/sub 4/F x 4H/sub 2/O in a stream of dry air at 120/sup 0/C. A comparative analysis of the IR spectra has provided evidence of alteration of the coordination of the oxalato groups in the anhydrous compounds, where they are bidentate, from that in the corresponding hydrates, where they are apparently tetradentate.

  17. Core-Mantle Partitioning of Volatile Siderophile Elements and the Origin of Volatile Elements in the Earth

    NASA Technical Reports Server (NTRS)

    Nickodem, K.; Righter, K.; Danielson, L.; Pando, K.; Lee, C.

    2012-01-01

    There are currently several hypotheses on the origin of volatile siderophile elements in the Earth. One hypothesis is that they were added during Earth s accretion and core formation and mobilized into the metallic core [1], others claim multiple stage origin [2], while some hypothesize that volatiles were added after the core already formed [3]. Several volatile siderophile elements are depleted in Earth s mantle relative to the chondrites, something which continues to puzzle many scientists. This depletion is likely due to a combination of volatility and core formation. The Earth s core is composed of Fe and some lighter constituents, although the abundances of these lighter elements are unknown [4]. Si is one of these potential light elements [5] although few studies have analyzed the effect of Si on metal-silicate partitioning, in particular the volatile elements. As, In, Ge, and Sb are trace volatile siderophile elements which are depleted in the mantle but have yet to be extensively studied. The metal-silicate partition coefficients of these elements will be measured to determine the effect of Si. Partition coefficients depend on temperature, pressure, oxygen fugacity, and metal and silicate composition and can constrain the concentrations of volatile, siderophile elements found in the mantle. Reported here are the results from 13 experiments examining the partitioning of As, In, Ge, and Sb between metallic and silicate liquid. These experiments will examine the effect of temperature, and metal-composition (i.e., Si content) on these elements in or-der to gain a greater understanding of the core-mantle separation which occurred during the Earth s early stages. The data can then be applied to the origin of volatile elements in the Earth.

  18. Advancing Access, Attribution, and Integration of Earth & Ocean Science Data: Integrated Services of the Marine Geoscience Data System and the Geoinformatics for Geochemistry Program

    NASA Astrophysics Data System (ADS)

    Lehnert, K. A.; Carbotte, S. M.; Ferrini, V.; Arko, R. A.; Chan, S.; Ryan, W. B.

    2010-12-01

    Development and operation of digital data collections are needed across all areas of the earth and ocean sciences to ensure access and preservation of data sets collected in support of earth and ocean sciences in order to maximize the return on research investments, while enabling verification of research results and contributing to new science initiatives. This is particularly true for data sets that are acquired at high cost, particularly in the marine environment, and that contain irreplaceable observations made of earth’s dynamic properties. The Marine Geoscience Data System (MGDS, www.marine-geo.org) and the Geoinformatics for Geochemistry Program (GfG, www.geoinfogeochem.org) have over the past decade developed, maintained, and operated community-driven data collections that support the preservation, discovery, retrieval, and analysis of a wide range of observational field and analytical data types from the marine and terrestrial environments, among them the PetDB database, the EarthChem data network, the Ridge2000 and MARGINS databases, the Antarctic and Southern Ocean Data System (ASODS), the Global Multi Resolution Topography Synthesis, and the System for Earth Sample Registration (SESAR). MGDS and GfG systems have been developed based on an active understanding of the practices, needs, and concerns of their user communities. They have engaged investigators in the design of the systems, seeking their feedback, and educating the community about responsibilities and benefits of scientific data management and sharing, and worked with funding agencies, editors, publishers, professional societies, and researchers to achieve broad community support, to proactively drive the development of community standards and best practices for data submission, data publication, data documentation, and data archiving, and to advance implementation. In a new formal partnership named IEDA (Integrated Earth Data Applications), the MGDS and GfG will be funded by the US National Science Foundation under a Cooperative Agreement to continue the operation of all MGDS and GfG data systems, while providing new integrated data services that will substantially enhance the utility of all data collection components, and improve data curation, interoperability and efficiency of operations. These will include an on-line service to improve ease of data submission across our user communities, a data publication service for scientists to publish their datasets with citable universal identifiers (DOIs), partnerships with institutions to ensure long-term archiving of data holdings, an authentication service for single sign-on to all systems, and operational services for shared vocabularies and to ease registration of common expeditions and geochemical datasets across our two systems.

  19. Investigation of Chemical and Physical Changes to Bioapatite During Fossilization Using Trace Element Geochemistry, Infrared Spectroscopy and Stable Isotopes

    NASA Astrophysics Data System (ADS)

    Suarez, C. A.; Kohn, M. J.

    2013-12-01

    Bioapatite in the form of vertebrate bone can be used for a wide variety of paleo-proxies, from determination of ancient diet to the isotopic composition of meteoric water. Bioapatite alteration during diagenesis is a constant barrier to the use of fossil bone as a paleo-proxy. To elucidate the physical and chemical alteration of bone apatite during fossilization, we analyzed an assortment of fossil bones of different ages for trace elements, using LA-ICP-MS, stable isotopes, and reflected IR spectroscopy. One set of fossil bones from the Pleistocene of Idaho show a diffusion recrystallization profile, however, rare earth element (REE) profiles indicate diffusion adsorption. This suggests that REE diffusion is controlled by changing (namely decreasing) boundary conditions (i.e. decreasing concentration of REE in surrounding pore fluids). Reflected IR analysis along this concentration profile reveal that areas high in U have lost type A carbonate from the crystal structure in addition to water and organics. Stable isotopic analysis of carbon and oxygen will determine what, if any, change in the isotopic composition of the carbonate component of apatite has occurred do to the diffusion and recrystallization process. Analysis of much older bone from the Cretaceous of China reveal shallow REE and U concentration profiles and very uniform reflected IR spectra with a significant loss of type A carbonate throughout the entire bone cortex. Analysis of stable isotopes through the bone cortex will be compared to the stable isotopes collected from the Pleistocene of Idaho.

  20. 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-ore granulite facies metamorphism homogenized zoned mineral grains without causing complete intergranular reequilibration and does not appear to have significantly affected the whole-rock REE distributions. These results demonstrate that extensive REE metasomatism can occur in hydrothermal systems at shallow to intermediate depths and that REE geochemistry may be useful in discerning the origin of skarns and skarn-related ore deposits.

  1. Uptake and distribution of rare earth elements in rice seeds cultured in fertilizer solution of rare earth elements.

    PubMed

    Yuan, D; Shan, X; Huai, Q; Wen, B; Zhu, X

    2001-04-01

    The uptake behavior of rare earth elements (REEs) under pot conditions using deionized water and a REE fertilizer solution as the culture media as well as the distribution of REEs in rice proteins were studied. The uptake of REEs in rice seeds increased dramatically after a lag period of approximately three days. Roots can accumulate a much higher content of REEs than germs and the resting seeds. The REE content in each water-soluble (albumin) and salt-soluble (globulin) component of the rice seeds accounted for 5-8% and 4-6% of the total REEs, respectively. However, there are less than 1.5% of the total REEs were found in the alcohol-soluble (prolamin) and acetic acid-soluble (glutelin) components. The high performance liquid chromatography (HPLC) in the gel permeation and the reserved-phase were used to monitor changes in the molecular weight distribution changes of the soluble proteins of rice seeds during germination after having been cultured in the same solution for seven days. No changes occurred in the prolamin, while a slight change occurred in the albumin, globulin and glutelin. Fractionation of the albumin of rice seeds cultured in a REE fertilizer solution on the Sephadex G-100 column indicated that REEs, especially Ce, La, Pr and Nd, were associated mainly with biological compounds of a molecular weight between 10,000 and 12,000. PMID:11302578

  2. Platinum Group Elements (PGE) geochemistry of komatiites and boninites from Dharwar Craton, India: Implications for mantle melting processes

    NASA Astrophysics Data System (ADS)

    Saha, Abhishek; Manikyamba, C.; Santosh, M.; Ganguly, Sohini; Khelen, Arubam C.; Subramanyam, K. S. V.

    2015-06-01

    High MgO volcanic rocks having elevated concentrations of Ni and Cr are potential hosts for platinum group elements (PGE) owing to their primitive mantle origin and eruption at high temperatures. Though their higher PGE abundance is economically significant in mineral exploration studies, their lower concentrations are also valuable geochemical tools to evaluate petrogenetic processes. In this paper an attempt has been made to evaluate the PGE geochemistry of high MgO volcanic rocks from two greenstone belts of western and eastern Dharwar Craton and to discuss different mantle processes operative at diverse geodynamic settings during the Neoarchean time. The Bababudan greenstone belt of western and Gadwal greenstone belt of eastern Dharwar Cratons are dominantly composed of high MgO volcanic rocks which, based on distinct geochemical characteristics, have been identified as komatiites and boninites respectively. The Bababudan komatiites are essentially composed of olivine and clinopyroxene with rare plagioclase tending towards komatiitic basalts. The Gadwal boninites contain clinopyroxene, recrystallized hornblende with minor orthopyroxene, plagioclase and sulphide minerals. The Bababudan komatiites are Al-undepleted type (Al2O3/TiO2 = 23-59) with distinctly high MgO (27.4-35.8 wt.%), Ni (509-1066 ppm) and Cr (136-3036 ppm) contents. These rocks have low ?PGE (9-42 ppb) contents with 0.2-2.4 ppb Iridium (Ir), 0.2-1.4 ppb Osmium (Os) and 0.4-4.4 ppb Ruthenium (Ru) among Iridium group PGE (IPGE); and 1.4-16.2 ppb Platinum (Pt), 2.8-19 ppb Palladium (Pd) and 0.2-9.8 ppb Rhodium (Rh) among Platinum group PGE (PPGE). The Gadwal boninites are high-Ca boninites with CaO/Al2O3 ratios varying between 0.8 and 1.0, with 12-24 wt.% MgO, 821-1168 ppm Ni and 2307-2765 ppm Cr. They show higher concentration of total PGE (82-207 ppb) with Pt concentration ranging from 13 to 19 ppb, Pd between 65 and 180 ppb and Rh in the range of 1.4-3 ppb compared to the Bababudan komatiites. Ir, Os and Ru concentrations range from 0.6 to 2.2 ppb, 0.2 to 0.6 ppb and 1.4 to 2.6 ppb respectively in IPGE. The PGE abundances in Bababudan komatiites were controlled by olivine fractionation whereas that in Gadwal boninites were influenced by fractionation of chromite and sulphides. The Al-undepleted Bababudan komatiites are characterized by low CaO/Al2O3, (Gd/Yb)N, (La/Yb)N, with positive Zr, Hf, Ti anomalies and high Cu/Pd, Pd/Ir ratios at low Pd concentrations suggesting the derivation of parent magma by high degrees (>30%) partial melting of mantle under anhydrous conditions at shallow depth with garnet as a residual phase in the mantle restite. The komatiites are geochemically analogous to Al-undepleted Munro type komatiites and their PGE compositions are consistent with Alexo and Gorgona komatiites. The S-undersaturated character of Bababudan komatiites is attributed to decompression and assimilation of lower crustal materials during magma ascent and emplacement. In contrast, the higher Al2O3/TiO2, lower (Gd/Yb)N, for Gadwal boninites in combination with negative Nb, Zr, Hf, Ti anomalies and lower Cu/Pd at relatively higher Pd/Ir and Pd concentrations reflect high degree melting of refractory mantle wedge under hydrous conditions in an intraoceanic subduction zone setting. Higher Pd/Ir ratios and S-undersaturation of these boninites conform to influx of fluids derived by dehydration of subducted slab resulting into high fluid pressure and metasomatism of mantle wedge.

  3. Rare earth element budgets in subduction-zone fluids

    NASA Astrophysics Data System (ADS)

    Tsay, A.; Zajacz, Z.; Sanchez-Valle, C.

    2012-12-01

    Subduction zone fluids play a fundamental role in the geochemical cycle of the Earth. The nature and composition of these fluids are determined by complex processes and still poorly understood. As a result of a variety of metasomatic and partial melting events, arc-related magmas display a typical trace element abundance spectrum, in which the rare earth elements' (REE) signature is an important record of petrogenetic processes. Therefore, investigating the behavior of REE in fluids at high pressure (P) and temperature (T) conditions is crucial for constraining fluid composition, as well as understanding subduction-zone processes in general. However, up to date, the experimental studies on REE solubility and speciation are limited to quite low P-T conditions (300 °C, saturated water vapor pressure) [1]. The theoretical predictions of the stability of REE complexes have been performed up to 350 °C [2] and 1000 °C, 0.5 GPa [3] by the extrapolation of thermodynamic data obtained at ambient conditions. In this study we present new experimental data on REE silicate (REE2Si2O7) solubility in aqueous quartz saturated fluids, containing various ligands, at conditions relevant for subducting slabs (600, 700, 800 °C, 2.6 GPa). The aim of the experiments was to investigate the relative effect of temperature and ligands on the solubility of REE. The experiments were conducted in an end-loaded piston-cylinder apparatus and the fluids were in situ sampled at P-T in the form of primary fluid inclusions in quartz [4]. The gold capsule was typically loaded with a chip of synthetic REE silicate (La,Nd,Gd,Dy,Er,Yb)2Si2O7, an aqueous fluid (~20 wt.%) and a piece of natural quartz. During the experiment (24-48 h) a thermal gradient along the capsule promoted intensive dissolution of quartz at the hottest part and precipitation of new quartz at the cooler part of the capsule, allowing the primary fluid inclusions to be trapped (~30-50 ?m). Rubidium and cesium were added to the fluid as the internal standards for LA-ICPMS analyses. The solubility of REE in quartz saturated water, free of additional ligands, increases more than an order of magnitude as temperature is increased from 600 °C to 800 °C. The effect of halogen ligands (Cl-, F-) on the solubility of REE was tested on experiments conducted at 800 °C. Addition of 1.5 m NaCl enhances the solubilities of all REE by a factor of 2 to 4 and induces moderate LREE/HREE fractionation; the La/Yb ratio increases by factor of 2. Unlike chlorine, the presence of fluorine ligands in the fluid (0.3 m NaF) promotes increase in HREE solubilities with almost no change in LREE solubilities compared to water, hence decreasing the La/Yb ratio by a factor of 2. The results of our experiments suggest that temperature plays an important role in mobilization of all REE by fluids. The presence of Cl- and F- ligands in the fluid shows opposing effects on the REE pattern: Cl- seems to be a more efficient ligand for LREE, while F- tends to form more stable complexes with HREE. [1] Migdisov A. A. et al., 2009, Geochim Cosmochim Acta, 73, 7087-7109 [2] Wood S. A. 1990b, Chem Geo., 82, 159-186 [3] Haas J. R. 1995, Geochim Cosmochim Acta, 59, 4329-4350 [4] Bali E. et al., 2011, Contrib Mineral Petrol, 161, 597-613

  4. 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

  5. Rare earth elements as geochemical tracers of regional groundwater mixing

    SciTech Connect

    Johannesson, K.H.; Stetzenbach, K.J.; Hodge, V.F. [Univ. of Nevada, Las Vegas, NV (United States)] [Univ. of Nevada, Las Vegas, NV (United States)

    1997-09-01

    The rare earth elements (REE) were analyzed in a groundwater system from south-central Nevada (i.e., Ash Meadows National Wildlife Refuge, the Spring Mountains, Pahranagat National Wildlife Refuge, and the Nevada Test Site) in order to investigate their potential use as tracers of regional groundwater flow. Previous investigations using conservative tracers (e.g., deuterium and uranium isotopes) identified recharge in local mountains as the primary source (60-70% of total discharge) for the springs in the regional discharge zone (i.e., Ash Meadows) with the remaining contribution being interbasin flow from the northeast. Initial mixing calculations for these groundwaters using shale-normalized REE patterns agreed well with the previous studies; however, because the REEs are not expected to behave conservatively in natural waters, the effect of both solution complexation, which acts to enhance the stability of the REEs in solution, as well as surface complexation, responsible for the particle reactive behavior of the REEs, were examined in subsequent mixing calculations. In order to assess the roles of solution and surface complexation, relative partitioning coefficients were estimated for each REE in each groundwater by evaluating the ratio of the ionic strength corrected {sub CO3}{beta}{sub 1}REE, {sub CO3}{beta}{sub 2}REE and [CO{sub 3}{sup 2-}]{sub F} to the first hydrolysis binding constants for the REEs. The relative partitioning coefficients were then used to calculate REE patterns expected to develop and persist in solution as a consequence of solution and surface complexation. The calculated REE values closely resembled the actual measured REE concentrations, suggesting that the REEs are, in fact, controlled by solution and surface complexation in these groundwaters. 81 refs., 7 figs., 7 tabs.

  6. Accumulation of rare earth elements in corn after agricultural application.

    PubMed

    Wang, Z; Liu, D; Lu, P; Wang, C

    2001-01-01

    Using both pot and plot experiments, the dose-dependent accumulation of rare earth elements (REs) in corn (Zea mays L.) after application of an agricultural REs mixture was measured. In the pot experiment, the dose-dependent accumulation of REs in corn root and stem was observed, but it could not be detected in corn leaf under the dosage of 20 mg REs kg(-1) soil (oven-dry mass). The non-observed effect concentration (NOEC) for accumulation of REs in corn seedling with the pot experiment was 1.0 mg REs kg(-1). In the plot experiment, the dose-dependent accumulation was observed at an early stage after application of REs and the NOEC value of 32 mg REs m(-2) was obtained. At harvest, no dose-dependent accumulation of REs was observed in any part of the corn. These results can be confirmed by the fingerprinting analysis based on the differences between La to RE ratios in the REs mixture and in pot or plot soil. We observed that the plant shows no preference on individual RE and the results of fingerprinting indicated clearly the incorporation of exogenous REs in plant tissues, in a similar manner as that observed in the dose-dependent distribution of RE concentrations. The results indicated also a translocation process of REs from plant root to leaf when applied to soil or from leaf to root when applied to leaf. A homeostatic regulation mechanism for excessive uptake of REs in plants is suggested to regulate the concentrations of REs in the plant. PMID:11215665

  7. 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 ?m-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 ?m) 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.

  8. Biogeochemistry of the rare-earth elements with particular reference to hickory trees

    USGS Publications Warehouse

    Robinson, W.O.; Bastron, H.; Murata, K.J.

    1958-01-01

    Hickory trees concentrate the rare-earth elements in their leaves to a phenomenal degree and may contain as much as 2300 p.p.m. of total rare earths based on the dry weight of the leaves. The average proportions of the individual elements (atomic percent of the total rare-earth elements) in the leaves are: Y 36, La 16, Ce 14, Pr 2, Nd 20, Sm 1, Eu 0.7, Gd 3, Tb 0.6, Dy 3, Ho 0.7, Er 2, Tm 0.2, Yb 1, and Lu 0.2. The similarity in the proportions of the rare-earth elements in the leaves and in the exchange complex of the soil on which the hickory trees grow indicates that the trees do not fractionate the rare earths appreciably. The variation of the rare-earth elements in the leaves and soils can be explained generally in terms of the relative abundance of the cerium group and the yttrium group, except for the element cerium. The large fluctuations in the proportion of cerium [Ce/(La + Nd) atomic ratios of 0.16 to 0.86] correlate with oxidation-reduction conditions in the soil profile. The substitution of dilute H2SO3 for dilute HC1 in the determination of available rare-earth elements brings about a large increase in the proportion of cerium that is extracted from an oxygenated subsoil. These relationships strongly suggest that quadrivalent cerium is present in oxygenated subsoil and is less available to plants than the other rare-earth elements that do not undergo such a change in valence. A few parts per billion of rare-earth elements have been detected in two samples of ground water. ?? 1958.

  9. Review of rare earth element concentrations in oil shales of the Eocene Green River Formation

    USGS Publications Warehouse

    Birdwell, Justin E.

    2012-01-01

    Concentrations of the lanthanide series or rare earth elements and yttrium were determined for lacustrine oil shale samples from the Eocene Green River Formation in the Piceance Basin of Colorado and the Uinta Basin of Utah. Unprocessed oil shale, post-pyrolysis (spent) shale, and leached shale samples were examined to determine if oil-shale processing to generate oil or the remediation of retorted shale affects rare earth element concentrations. Results for unprocessed Green River oil shale samples were compared to data published in the literature on reference materials, such as chondritic meteorites, the North American shale composite, marine oil shale samples from two sites in northern Tibet, and mined rare earth element ores from the United States and China. The Green River oil shales had lower rare earth element concentrations (66.3 to 141.3 micrograms per gram, ?g g-1) than are typical of material in the upper crust (approximately 170 ?g g-1) and were also lower in rare earth elements relative to the North American shale composite (approximately 165 ?g g-1). Adjusting for dilution of rare earth elements by organic matter does not account for the total difference between the oil shales and other crustal rocks. Europium anomalies for Green River oil shales from the Piceance Basin were slightly lower than those reported for the North American shale composite and upper crust. When compared to ores currently mined for rare earth elements, the concentrations in Green River oil shales are several orders of magnitude lower. Retorting Green River oil shales led to a slight enrichment of rare earth elements due to removal of organic matter. When concentrations in spent and leached samples were normalized to an original rock basis, concentrations were comparable to those of the raw shale, indicating that rare earth elements are conserved in processed oil shales.

  10. Minimum-time Earth–Moon and Moon–Earth orbital maneuvers using time-domain finite element method

    Microsoft Academic Search

    S. A. Fazelzadeh; G. A. Varzandian

    2010-01-01

    In this paper, the minimum-time orbital trajectories for Earth–Moon and Moon–Earth flights of a continuous-thrust spacecraft are obtained by the time-domain finite element method. The problem is formulated using a simplified version of the restricted three-body model at the Cartesian coordinate system. Moreover, the performance index is considered as the minimum-time problem with free final time. Through the calculus of

  11. Geochemical Constraints on Core Formation in the Earth

    NASA Technical Reports Server (NTRS)

    Jones, John H.; Drake, Michael J.

    1986-01-01

    New experimental data on the partitioning of siderophile and chalcophile elements among metallic and silicate phases may be used to constrain hypotheses of core formation in the Earth. Three current hypotheses can explain gross features of mantle geochemistry, but none predicts siderophile and chalcophile element abundances to within a factor of two of observed values. Either our understanding of metal-silicate interactions and/or our understanding of the early Earth requires revision.

  12. Rare Earth Elements: A Tool for Understanding the Behaviour of Trivalent Actinides in the Geosphere

    SciTech Connect

    Buil, Belen; Gomez, Paloma; Garralon, Antonio; Turrero, M. Jesus [Medioambiente, CIEMAT, Avda. Complutense 22, Madrid, 28040 (Spain)

    2007-07-01

    Rare earth element (REE) concentrations have been determined in groundwaters, granite and fracture fillings in a restored uranium mine. The granitoids normalized REE patterns of groundwaters show heavy rare earth elements (HREE)-enrichment and positive Eu anomalies. This suggests that the REE are fractionated during leaching from the source rocks by groundwaters. Preferential leaching of HREE would be consistent with the greater stability of their aqueous complexes compared to those of the light rare earth elements (LREE), together with the dissolution of certain fracture filling minerals, dissolution/alteration of phyllosilicates and colloidal transport. (authors)

  13. Rare earth elements in weathering profiles and sediments of Minnesota: Implications for provenance studies

    USGS Publications Warehouse

    Morey, G.B.; Setterholm, D.R.

    1997-01-01

    The relative abundance of rare earth elements in sediments has been suggested as a tool for determining their source rocks. This correlation requires that weathering, erosion, and sedimentation do not alter the REE abundances, or do so in a predictable manner. We find that the rare earth elements are mobilized and fractionated by weathering, and that sediments derived from the weathered materials can display modifications of the original pattern of rare earth elements of some due to grain-size sorting of the weathered material. However, the REE distribution pattern of the provenance terrane can be recognized in the sediments.

  14. The direct electrochemistry of cytochrome c at the nanometer-sized rare earth element oxide particle-modified gold electrodes

    Microsoft Academic Search

    Xiaogang Qu; Xiangting Dong; Ziyong Cheng; Tianhong Lu; Shaojun Dong

    1996-01-01

    The direct electrochemistry of cytochrome c was studied at nanometer-sized rare earth element dioxide particle-modified gold electrodes. It was demonstrated that rare earth element oxides can accelerate the electrochemical reaction of cytochrome c and the reversibility of the electrochemical reaction of cytochrome c was related to the size of rare earth element oxide particles.

  15. PII S0016-7037(02)00888-8 EXAFS study of rare-earth element coordination in calcite

    E-print Network

    Peale, Robert E.

    PII S0016-7037(02)00888-8 EXAFS study of rare-earth element coordination in calcite E. J. ELZINGA,1-structure (EXAFS) spectroscopy is used to characterize the local coordination of selected rare-earth elements (Nd3 for the increased coordination for the larger rare-earth elements involves bidentate ligation from a CO3 group

  16. Speciation of rare earth elements in soil and accumulation by wheat with rare earth fertilizer application.

    PubMed

    Zhang, S; Shan, X Q

    2001-01-01

    A greenhouse study was conducted to investigate the accumulation of rare earth elements (REEs), La, Ce, Pr and Nd, in winter wheat (Triticum aestivum L.), and the speciation of these elements in soil following the application of REE-based fertilizers. Improved crop yield was confirmed by the experiment. The accumulation behavior of La, Ce, Pr and Nd in wheat varied depending on the concentration of REE fertilizer application, i.e. increased with increasing REE concentration at low fertilization application, constant over the medium REE range, and decreased with increasing REE concentration at high fertilizer application. Significant negative correlation was obtained between REE contents in roots and soil pH (r = -0.5787 to -0.8442 for La). REEs in both the fertilized and unfertilized soils were fractionated by a three-stage sequential extraction procedure into three chemically distinct fractions: water soluble, exchangeable and carbonate bound (B1), Fe-Mn oxide bound (B2), and organic and sulfide bound (B3). REEs in fertilized soils were found mainly in the B2 and B3 fractions, with only a small amount in the B1 fraction. REEs in B1 and B2 fractions were negatively correlated with soil pH (r = -0.6892 to -0.8927 and -0.7462 to -0.9482). Significant correlation was obtained between REEs in B1 fraction and REE contents in root. The correlation coefficients ranged from 0.6159 to 0.7410 when fertilizer application was lower than 20.0 mg/kg soil. No acceptable relationship was observed between REE contents in shoot and any of the extractable fractions in soils. PMID:11291446

  17. U-Pb SHRIMP geochronology and trace-element geochemistry of coesite-bearing zircons, North-East Greenland Caledonides

    USGS Publications Warehouse

    McClelland, W.C.; Power, S.E.; Gilotti, J.A.; Mazdab, F.K.; Wopenka, B.

    2006-01-01

    Obtaining reliable estimates for the timing of eclogite-facies metamorphism is critical to establishing models for the formation and exhumation of high-pressure and ultrahigh-pressure (UHP) metamorphic terranes in collisional orogens. The presence of pressure-dependent phases, such as coesite, included in metamorphic zircon is generally regarded as evidence that zircon growth occurred at UHP conditions and, ifdated, should provide the necessary timing information. We report U-Pb sensitive high-resolution ion microprobe (SHRIMP) ages and trace-element SHRIMP data from coesite-bearing zircon suites formed during UHP metamorphism in the North- East Greenland Caledonides. Kyanite eclogite and quartzofeldspathic host gneiss samples from an island in J??kelbugt (78??00'N, 18??04'W) contained subspherical zircons with well-defined domains in cathodoluminescence (CL) images. The presence of coesite is confirmed by Raman spectroscopy in six zircons from four samples. Additional components of the eclogite-facies inclusion suite include kyanite, omphacite, garnet, and rutile. The trace-element signatures in core domains reflect modification of igneous protolith zircon. Rim signatures show flat heavy rare earth element (HREE) patterns that are characteristic of eclogite-facies zircon. The kyanite eclogites generally lack a Eu anomaly, whereas a negative Eu anomaly persists in all domains of the host gneiss. The 207Pb- corrected 206Pb/238U ages range from 330 to 390 Ma for the host gneiss and 330-370 Ma for the kyanite eclogite. Weighted mean 206Pb/238U ages for coesite-bearing domains vary from 364 ?? 8 Ma for the host gneiss to 350 ?? 4 Ma for kyanite eclogite. The combined U-Pb and REE data interpreted in conjunction with observed CL domains and inclusion suites suggest that (1) Caledonian metamorphic zircon formed by both new zircon growth and recrystallization, (2) UHP metamorphism occurred near the end of the Caledonian collision, and (3) the 30-50m.y. span of ages records long residence times at eclogite-facies conditions for the UHProcks of North-East Greenland. This spread in observed ages is interpreted to be characteristic of metamorphic rocks that have experienced relatively long (longer than 10 m.y.) residence times at UHP conditions. ?? 2006 Geological Society of America.

  18. Technical Information Resource on Rare Earth Elements Now Available to Public and Private Sector Stakeholders

    EPA Science Inventory

    A new EPA technical information resource, ?Rare Earth Elements: A Review of Production, Processing, Recycling, and Associated Environmental Issues? has been produced as an introductory resource for those interested in learning more about REE mining and alternatives to meet demand...

  19. Rare Earth Element Partition Coefficients from Enstatite/Melt Synthesis Experiments

    NASA Technical Reports Server (NTRS)

    Schwandt, Craig S.; McKay, Gordon A.

    1997-01-01

    Enstatite (En(80)Fs(19)Wo(01)) was synthesized from a hypersthene normative basaltic melt doped at the same time with La, Ce, Nd, Sm, Eu, Dy, Er, Yb and Lu. The rare earth element concentrations were measured in both the basaltic glass and the enstatite. Rare earth element concentrations in the glass were determined by electron microprobe analysis with uncertainties less than two percent relative. Rare earth element concentrations in enstatite were determined by secondary ion mass spectrometry with uncertainties less than five percent relative. The resulting rare earth element partition signature for enstatite is similar to previous calculated and composite low-Ca pigeonite signatures, but is better defined and differs in several details. The partition coefficients are consistent with crystal structural constraints.

  20. Analysis for the rare-earth elements by neutron activation and Ge(Li) spectrometry

    Microsoft Academic Search

    E. B. Denechaud; P. A. Helmke; L. A. Haskin

    1970-01-01

    A procedure for analysis of 12 of the rare-earths, tested on more than a hundred samples of rocks and minerals, is described.\\u000a Carrier is added for each element to be determined. Samples are fused with Na2O2. The rare-earths are separated as a group, then precipitated and mounted as oxalates for Ge(Li) spectrometry. Following radioassay,\\u000a chemical yields for the individual rare-earths

  1. FLUORESCENCE PROPERTIES OF As2S3 GLASS DOPED WITH RARE-EARTH ELEMENTS

    Microsoft Academic Search

    M. Iovu; A. Andriesh; I. Culeac

    Chalcogenide glasses doped with various rare-earth ions are extensively studied as potential materials for fiber optic amplifiers operating at 1.3 and 1.5 ?m telecommunication windows. The experimental results on optical absorption and photoluminescence of arsenic sulfide glasses and optical fibers doped with rare-earth elements (Pr3+, Sm3+, Er3+ and Dy3+) are presented. Near the absorption edge the rare-earth impurities affect strongly

  2. Activation analysis of rare-earth elements in opium and cannabis samples

    Microsoft Academic Search

    G. Henke; Wilhelms-Universitdt Miinster

    1977-01-01

    Rare earth concentrations in 65 Opium, Cannabis and Cannabis resin samples seized from various parts of world were determined\\u000a by destructive NAA. Great variations in absolute element concentrations, but only small significant differences of rare earth\\u000a concentration ratios were found, indicating inconsiderable biogeochemical fractionation. The mean values of these ratios correspond\\u000a with the relative abundances of the rare earths in

  3. Maria Goeppert Mayer's Theoretical Work on Rare-Earth and Transuranic Elements

    Microsoft Academic Search

    Frank Y. Wang

    2008-01-01

    After the discovery of element 93 neptunium by Edwin McMillan and Philip H. Abelson in 1941, Maria Goeppert Mayer applied the Thomas-Fermi model to calculate the electronic configuration of heavy elements and predicted the occurrence of a second rare-earth series in the vicinity of elements 91 or 92 extending to the transuranic elements. Mayer was motivated by Enrico Fermi, who

  4. Maria Goeppert Mayer's Theoretical Work on Rare-Earth and Transuranic Elements

    Microsoft Academic Search

    Frank Y. Wang

    2008-01-01

    After the discovery of element 93 neptunium by Edwin McMillan and Philip H.\\u000aAbelson in 1941, Maria Goeppert Mayer applied the Thomas-Fermi model to\\u000acalculate the electronic configuration of heavy elements and predicted the\\u000aoccurrence of a second rare-earth series in the vicinity of elements 91 or 92\\u000aextending to the transuranic elements. Mayer was motivated by Enrico Fermi, who

  5. Use of rare earth elements as external markers for mean retention time measurements in ruminants

    E-print Network

    Paris-Sud XI, Université de

    in ruminants Laurence BERNARD*, Michel DOREAU Unité de Recherche sur les Herbivores, INRA de Clermont -- The present review deals with the utilisation of rare earth (RE) elements as particulate markers for ruminant earth / retention time / feedstuff / methodology / ruminant Résumé -- Utilisation des terres rares comme

  6. Mechanochemical decomposition of monazite to assist the extraction of rare earth elements

    Microsoft Academic Search

    Wantae Kim; Inkook Bae; Soochun Chae; Heeyoung Shin

    2009-01-01

    Mechanochemical decomposition by milling a mixture of monazite and sodium hydroxide powder and subsequent leaching by sulfuric acid for the extraction of rare earth elements at room temperature has been investigated. The milling of the mixture allows the mechanochemical formation of rare earth hydroxides and sodium phosphate as milling progresses. Nearly all the monazite is decomposed within 120min under the

  7. EXTRACTION AND SEPARATION OF YTTRIUM AND RARE-EARTH ELEMENTS FOUND IN EUXENITE

    Microsoft Academic Search

    Gruzensky

    1960-01-01

    Studies relative to the separation of yttrium and the individual rare-; earth elements (lanthanons) from mixtures in which they occur was undertaken at ; the Federal Bureau of Mines Albany Metallurgy Research Center and resuited in the ; development of a solvent extraction method by which yttrium can be separated from ; the rare-earth metals. A separation factor of l0.93

  8. Separation of rare earth elements from sulfate leach liquor by heterocyclic nitrogen compound

    Microsoft Academic Search

    M. Mahmoud GHADA; T. El Hazek NABIL; M. Farag AHMAD; M. El Hussaini OMNEYA

    2008-01-01

    Separation of rare earth elements by solvent extraction has actually been widely used in various fields from analytical chemistry to hydrometallurgy. A representative ore sample obtained from Kadabora Batholiths-Eastern Desert of Egypt, containing the multiple oxides rare earth minerals: Samarskite, Fergusonite, Betafite, and Pyrochlore, was subjected to sulfuric acid leaching. Different sets of equilibrium loading experiments were carried out on

  9. Use of GEOCHEM-PC to predict rare earth element (REE) species in nutrient solutions

    Microsoft Academic Search

    E. Diatloff; C. J. Asher; F. W. Smith

    1993-01-01

    The interpretation of results of some experiments examining effects of rare earth elements (REE) on plant growth may have been complicated by rare earth phosphate precipitation. Simulations were undertaken using the computer model GEOCHEM-PC to define REE solubility limits and predict REE species in low and high ionic strength nutrient solutions. In low ionic strength solutions containing 5 µM P,

  10. Input impedance and gain of monopole elements with disk ground planes on flat earth

    Microsoft Academic Search

    M. M. Weiner

    1990-01-01

    This paper extends previously reported results for a quarterwave monopole element on a disk ground plane in free space to the case where the disk ground plane rests on flat earth. Numerical results are obtained by utilizing Richmond's method of moments computer program for disk ground planes over flat earth.

  11. Effect of Rare Earth Elements on Anisotropy and Microstructure of Al-Li Alloy 2195 Sheets

    Microsoft Academic Search

    Xu Yue; Geng Jiping; Liu Yufeng

    2006-01-01

    For the purpose of decreasing the applied limitation resulting from the anisotropic mechanical property of Al-Li alloy 2195, this study employed a complex heat treatment process, involving the pre-tension, thermo-infiltration of the rare earth element Ce, solution treatment, and artificial aging technology. The results indicate that the infiltration of rare earth element Ce benefits the abatement of anisotropy of Al-Li

  12. Hydrometallurgical separation of rare earth elements, cobalt and nickel from spent nickel–metal–hydride batteries

    Microsoft Academic Search

    Luiz Eduardo Oliveira Carmo Rodrigues; Marcelo Borges Mansur

    2010-01-01

    The separation of rare earth elements, cobalt and nickel from NiMH battery residues is evaluated in this paper. Analysis of the internal content of the NiMH batteries shows that nickel is the main metal present in the residue (around 50% in weight), as well as potassium (2.2–10.9%), cobalt (5.1–5.5%), rare earth elements (15.3–29.0%) and cadmium (2.8%). The presence of cadmium

  13. Research of the entry of rare earth elements Eu 3+ and La 3+ into plant cell

    Microsoft Academic Search

    Yongsheng Gao; Fuli Zeng; An Yi; Shi Ping; Lanhua Jing

    2003-01-01

    Whether rare earth elements can enter into plant cells remains controversial. This article discusses the ultracellular structural\\u000a localization of lanthanum (La3+) and europium (Eu3+) in the intact plant cells fed by rare earth elements Eu3+ and La3+. Eu-TTA fluorescence analysis of the plasmalemma, cytoplast, and mitochondria showed that Eu3+ fluorescence intensities in such structures significantly increased. Eu3+ can directly enter

  14. Sensitive detection of flame absorption spectra of rare-earth elements with a dye laser

    Microsoft Academic Search

    M. Maeda; F. Ishitsuka; M. Matsumoto; Y. Miyazoe

    1976-01-01

    The dye-laser amplified absorption method is applied to observe the atomic absorption lines of rare-earth elements in a nitrous-oxide-acetylene flame. All of the rare-earth elements except Pm are analyzed and about 1200 lines have been recorded within the continuous spectral region from 432 to 670 nm. A much larger number of absorption lines can be detected than those measured by

  15. Impurity Absorption Loss due to Rare Earth Elements in a Fluoride Glass

    Microsoft Academic Search

    Yasutake Ohishi; Seiko Mitachi; Shuichi Shibata; Toyotaka Manabe

    1981-01-01

    Optical spectra for each of the rare earth element doped BaF2-GdF3-ZrF4 glasses were measured. It was found that, in the 2-5 mum wavelength region, Ce, Pr, Nd, Sm, Tb and Dy contribute to the absorption loss and the loss magnitude due to each rare earth element of lppmw is several tens of dB per kilometer at the absorption peaks. It

  16. Laser-induced luminescence of rare-earth elements in natural fluor-apatites

    Microsoft Academic Search

    R. Reisfeld; M. Gaft; G. Boulon; C. Panczer; C. K. Jørgensen

    1996-01-01

    The luminescence spectra of naturally occurring fluor-apatites containing traces of rare-earth elements have been compared with synthetic fluor-apatites to which single rare-earth elements have been intentionally added. Comparison of the laser-induced spectra obtained after different time delays allows identification of the following luminescence centers: Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Tb3+, Dy3+, Er3+, Tm3+, Yb3+ and possibly Yb2+. The technique described

  17. Overview of the effects of impurities and rare earth elements in Al?Li alloys

    Microsoft Academic Search

    L. Meng; X. L. Zheng

    1997-01-01

    The current status of the effects of impurities and rare earth elements on the microstructure and the mechanical properties of Al?Li alloys has been surveyed in the present paper. Particular attention has been paid to the mechanical properties in respect of different conditions and the mechanisms responsible for both impurity-induced embrittlement and rare earth element microalloying. Al?Li alloys usually show

  18. Ligand extraction of rare earth elements from aquifer sediments: Implications for rare earth element complexation with organic matter in natural waters

    Microsoft Academic Search

    Jianwu Tang; Karen H. Johannesson

    2010-01-01

    The ability of organic matter as well as carbonate ions to extract rare earth elements (REEs) from sandy sediments of a Coastal Plain aquifer was investigated for unpurified organic matter from different sources (i.e., Mississippi River natural organic matter, Aldrich humic acid, Nordic aquatic fulvic acid, Suwannee River fulvic acid, and Suwannee River natural organic matter) and for extraction solutions

  19. Rare earth elements in hydrothermal systems: Estimates of standard partial molal thermodynamic properties of aqueous complexes of the rare earth elements at high pressures and temperatures

    Microsoft Academic Search

    Johnson R. Haas; Everett L. Shock; David C. Sassani

    1995-01-01

    Standard partial molal thermodynamic properties including association constants for 246 inorganic aqueous rare earth element (REE) complexes with chloride, fluoride, hydroxide, carbonate, sulfate, bicarbonate, nitrate, and orthophosphate can be calculated at pressures from 1 to 5000 bars and temperatures from 0 to 1000°C, using experimental data from the literature and correlation algorithms. Predicted association constants for REE complexes are used

  20. Highly Siderophile Elements in the Earth's Mantle as a Clock for the Moon-forming Impact

    E-print Network

    Jacobson, Seth A; Raymond, Sean N; O'Brien, David P; Walsh, Kevin J; Rubie, David C

    2015-01-01

    According to the generally accepted scenario, the last giant impact on the Earth formed the Moon and initiated the final phase of core formation by melting the Earth's mantle. A key goal of geochemistry is to date this event, but different ages have been proposed. Some argue for an early Moon-forming event, approximately 30 million years (Myr) after the condensation of the first solids in the Solar System, whereas others claim a date later than 50 Myr (and possibly as late as around 100 My) after condensation. Here we show that a Moon-forming event at 40 Myr after condensation, or earlier, is ruled out at a 99.9 per cent confidence level. We use a large number of N-body simulations to demonstrate a relationship between the time of the last giant impact on an Earth-like planet and the amount of mass subsequently added during the era known as Late Accretion. As the last giant impact is delayed, the late-accreted mass decreases in a predictable fashion. This relationship exists within both the classical scenario...

  1. Exploration Geochemistry.

    ERIC Educational Resources Information Center

    Closs, L. Graham

    1983-01-01

    Contributions in mineral-deposit model formulation, geochemical exploration in glaciated and arid environments, analytical and sampling problems, and bibliographic research were made in symposia held and proceedings volumes published during 1982. Highlights of these symposia and proceedings and comments on trends in exploration geochemistry are…

  2. Exploration Geochemistry

    E-print Network

    Michelson, David G.

    Exploration Geochemistry Initiative MDRU is an internationally recognized, collaborative research exploration problems and training the next generation of exploration geologists. e MDRU Exploration that will significantly increase the amount and quality of research and training in the discipline of mineral exploration

  3. Rare earth element recycling from waste nickel-metal hydride batteries.

    PubMed

    Yang, Xiuli; Zhang, Junwei; Fang, Xihui

    2014-08-30

    With an increase in number of waste nickel-metal hydride batteries, and because of the importance of rare earth elements, the recycling of rare earth elements is becoming increasingly important. In this paper, we investigate the effects of temperature, hydrochloric acid concentration, and leaching time to optimize leaching conditions and determine leach kinetics. The results indicate that an increase in temperature, hydrochloric acid concentration, and leaching time enhance the leaching rate of rare earth elements. A maximum rare earth elements recovery of 95.16% was achieved at optimal leaching conditions of 70°C, solid/liquid ratio of 1:10, 20% hydrochloric acid concentration, -74?m particle size, and 100min leaching time. The experimental data were best fitted by a chemical reaction-controlled model. The activation energy was 43.98kJ/mol and the reaction order for hydrochloric acid concentration was 0.64. The kinetic equation for the leaching process was found to be: 1-(1-x)(1/3)=A/?r0[HCl](0.64)exp-439,8008.314Tt. After leaching and filtration, by adding saturated oxalic solution to the filtrate, rare earth element oxalates were obtained. After removing impurities by adding ammonia, filtering, washing with dilute hydrochloric acid, and calcining at 810°C, a final product of 99% pure rare earth oxides was obtained. PMID:25089667

  4. LIQUID-LIQUID EXTRACTION OF RARE-EARTH ELEMENTS

    Microsoft Academic Search

    D. J. Bauer; A. C. Rice; J. S. Berber

    1960-01-01

    Liquid-liquid extraction techniques were investigated for use in ; fractionation of rare-earth solutions. Laboratory extractions using TBP for ; ceric nitrate resulted in almost complete extraction. Tests with primary amines ; were also promising. In scale-up extractions of the ceric nitrate procedure 84% ; efficiency was obtained. (J.R.D.);

  5. Project EARTH-11-RK2: Magma dynamics: Trace element transport in simulations of channelised

    E-print Network

    Henderson, Gideon

    of magmatic channelisation, both in terms of the fluid dynamics and trace element transport. Since the scale activity of the project will be the development and analysis of mathematical/computational modelsProject EARTH-11-RK2: Magma dynamics: Trace element transport in simulations of channelised

  6. Acid extractable rare earth elements in Florida citrus soils and trees

    Microsoft Academic Search

    Heinz K. Wutscher; Robert E. Perkins

    1993-01-01

    To determine the levels of elements not usually included in soil analyses, aqua regia extracts from 10 soils in eight locations throughout the Florida citrus belt were analyzed for 14 rare earth elements (lanthanides), scandium, and yttrium with an IGP spectrophotometer. Leaves, bark, wood, and roots of citrus trees growing at two of the sampling locations, a fertilizer (14% N?l.7%

  7. Determination of rare earth elements in rice by INAA and ICP-MS

    Microsoft Academic Search

    M. Pham Thi Huynh; F. Carrot; S. Chu Pham Ngoc; M. Dang Vu; G. Revel

    1997-01-01

    Irrigation of rice plants with a solution of rare earth elements increases both the production capacity and the resistance to disease. Assuming that the treated plants remain expendable, the different parts of plants, root stalk and grain, were analyzed by instrumental neutron activation analysis (INAA) and by mass spectrometry after plasma excitation (ICP-MS). About 40 elements were determined. The results

  8. Rare earth element evidence for differentiation of McMurdo volcanics, Ross Island, Antarctica

    Microsoft Academic Search

    Shen-Su Sun; Gilbert N. Hanson

    1976-01-01

    Eighteen samples of the McMurdo volcanics on Ross Island, Antarctica consisting of basanitoid, trachybasalt and phonolite have been analyzed for rare earth elements (REE) in order to determine the details of differentiation using quantitative trace element modeling. The basanitoids have REE patterns similar to those for alkali basalts or nephelinites from ocean islands. Since there is no correlation between REE

  9. Matrix Elements and Operator Equivalents Connected with the Magnetic Properties of Rare Earth Ions

    Microsoft Academic Search

    K W H Stevens; K. W. H

    1952-01-01

    An account is given of the methods used to determine the matrix elements of crystal field potentials with particular reference to rare earth ions. Emphasis is laid on the importance of Wigner coefficients in such problems and the idea of using equivalent angular momentum operators is developed. For convenience in applying the results tables of matrix elements are included.

  10. Study on Orbital Decay of Near Earth Satellites with KS Orthogonal Elements

    NASA Astrophysics Data System (ADS)

    Ps, Sandeep

    STUDY ON ORBITAL DECAY OF NEAR EARTH SATELLITES WITH KS ORTHOGONAL ELEMENTS SANDEEP P S The knowledge of satellite orbit decay and its expected life prior to launch is necessary for mission planning purpose. Several sets of data for various parametric studies is sought quite often, it is necessary to minimize computational time involved for generating decay predictions, keeping the prediction accuracy normally good. A number of factors play dominant role in perturbation modelling for near earth satellites such as oblateness of the Earth, presence of the atmosphere, luni-solar attraction and solar radiation pressure. This paper concerns with the study of orbital decay of near earth satellites with KS orthogonal elements, which provide accurate orbit predictions at low computational time. Perturbations considered are due to oblateness of the Earth and the atmospheric drag. The Earth’s zonal harmonic terms J2 to J6 are included and the drag is modeled with an analytical diurnally oblate atmosphere. Effect of Earth’s geomagnetic and solar activity is included in density and density scale height computations. JACCHIA77 atmospheric model is utilized. The developed software is validated with the orbital data of decayed objects taken from www.space-track.org.

  11. A programme for electron-impact broadening parameter calculations of ionized rare-earth element lines

    E-print Network

    L. C. Popovic; M. S. Dimitrijevic

    1998-05-15

    In order to provide atomic data needed for astrophysical investigations, a set of electron-impact broadening parameters for ionized rare-earth element lines should be calculated. We are going to calculate the electron-impact broadening parameters for more than 50 transitions of ionized rare-earth elements. Taking into account that the spectra of these elements are very complex, for calculation we can use the modified semiempirical approach - MSE or simplified MSE. Also, we can estimate these parameters on the basis of regularities and systematic trends.

  12. Experimental productivity rate optimization of rare earth element separation through preparative solid phase extraction chromatography.

    PubMed

    Knutson, Hans-Kristian; Max-Hansen, Mark; Jönsson, Christian; Borg, Niklas; Nilsson, Bernt

    2014-06-27

    Separating individual rare earth elements from a complex mixture with several elements is difficult and this is emphasized for the middle elements: Samarium, Europium and Gadolinium. In this study we have accomplished an overloaded one-step separation of these rare earth elements through preparative ion-exchange high-performance liquid chromatography with an bis (2-ethylhexyl) phosphoric acid impregnated column and nitric acid as eluent. An inductively coupled plasma mass spectrometry unit was used for post column element detection. The main focus was to optimize the productivity rate, subject to a yield requirement of 80% and a purity requirement of 99% for each element, by varying the flow rate and batch load size. The optimal productivity rate in this study was 1.32kgSamarium/(hmcolumn(3)), 0.38kgEuropium/(hmcolumn(3)) and 0.81kgGadolinium/(hmcolumn(3)). PMID:24835593

  13. Rare earth element concentrations and speciation in organic-rich blackwaters of the Great Dismal Swamp, Virginia, USA

    E-print Network

    Burdige, David

    Rare earth element concentrations and speciation in organic-rich blackwaters of the Great Dismal Concentrations of rare earth elements (REE), major inorganic solutes, and dissolved organic carbon (DOC) were crustal (UCC) values. Rare earths are positively correlated to DOC concentrations in Great Dismal Swamp

  14. Comparison of Highly Siderophile Elements Between Earth and Mars

    NASA Astrophysics Data System (ADS)

    Schmidt, G.

    2007-07-01

    The similarity in HSE ratios and the very systematic compatible-incompatible element behaviour of IIIAB irons, pallasitic metal and the martian crust strongly supports a genetic link between these meteorites and the HSE component of the martian crust.

  15. A predictive model for rare earth element partitioning between clinopyroxene and anhydrous silicate melt

    Microsoft Academic Search

    Bernard J. Wood; Jonathan D. Blundy

    1997-01-01

    We present a quantitative model to describe the partitioning of rare earth elements (REE) and Y between clinopyroxene and\\u000a anhydrous silicate melt as a function of pressure (P), temperature (T) and bulk composition (X). The model is based on the Brice (1975) equation, which relates the partition coefficient of element i (D\\u000a \\u000a i\\u000a ) to that of element o (D

  16. Advances in Understanding Elements of the Sun—Earth Links

    Microsoft Academic Search

    Jean-Pierre Rozelot; Sandrine Lefebvre

    2006-01-01

    The study of the Sun–Earth connections is a science in full effervescence, as much as for the physical problems that arise\\u000a as for its growing impact on our societies. This last case is illustrated by the emergence of a new field of research called\\u000a Space Weather. The launch of this new concept (translated in French by météorologie de l’espace) deserves

  17. Extension of lattice strain theory to mineral/mineral rare-earth element partitioning: An approach for assessing disequilibrium

    E-print Network

    Lee, Cin-Ty Aeolus

    Extension of lattice strain theory to mineral/mineral rare-earth element partitioning: An approach a Department of Earth Science, MS-126, Rice University, 6100 Main Street, Houston, TX 77005, USA b Earth 2006; accepted in revised form 20 September 2006 Abstract Olivine/melt and orthopyroxene/melt rare-earth

  18. Rare Earth Elemental Signatures in Fungal Fruiting Bodies as Probes into Mineral Breakdown Reactions in Post-glacial Landscapes

    NASA Astrophysics Data System (ADS)

    Bryce, J. G.; Hobbie, E. A.

    2008-12-01

    The application of rare earth element (REE) abundances in low temperature geochemistry and biogeochemistry has improved our understanding of the cycling of various micro- and macronutrients from the bedrock into terrestrial ecosystems. In many continental rocks, REEs are concentrated in accessory phases such as apatite and monazite. These phosphate mineral phases break down readily and may be especially important nutrient sources, particularly for P and Ca, in recently glaciated terrains. Several studies (e.g., 1-3) have suggested that the presence of ectomycorrhizal (ECM) fungi, due to the organic acids they secrete, may play an especially important role in this weathering process. A field-based experiment implementing mesh bags doped with specific mineral compositions confirmed that ECM fungal tissues do record the REE signatures of the minerals they break down (4). In an effort to understand the relative role different ECM fungi may play in mineral breakdown reactions, we have measured REE abundances in tissues of several ECM fruiting bodies. Our preliminary data include Russula, Suillus Americana, Leccinum and Lactarius ECM fungi from three postglacial landscapes. At a given site, the relative abundance of REEs varies between the different ECM fungi. Interestingly, we found distinctions in tissue La/Ce values at two of the sites. Leccinum, a deep rooter, shows much lower La/Ce than the companion Russula and Lactarius samples from the same site. Similarly Suillus tissues demonstrated lower La/Ce when compared to Russula growing nearby. Lower La/Ce is consistent with enhanced dissolution of the mineral apatite, a common accessory phase. While the influence of symbiotic host (beech vs. oak vs. pine) may play some role in the distinctive REE signatures recorded by the fruiting bodies, we attribute the observed differences to organic acid production and tendency to colonize in different horizons of the soil profile. (1) Wallander, Plant and Soil, 2000; (2) Blum et al., Nature, 2002; (3) Hoffland et al., Front Ecol Environ., 2003; (4) Hagerburg et al., Plant and Soil, 2003.

  19. Research of the entry of rare earth elements Eu3+ and La3+ into plant cell.

    PubMed

    Gao, Yongsheng; Zeng, Fuli; Yi, An; Ping, Shi; Jing, Lanhua

    2003-03-01

    Whether rare earth elements can enter into plant cells remains controversial. This article discusses the ultracellular structural localization of lanthanum (La(3+)) and europium (Eu(3+)) in the intact plant cells fed by rare earth elements Eu(3+) and La(3+). Eu-TTA fluorescence analysis of the plasmalemma, cytoplast, and mitochondria showed that Eu(3+) fluorescence intensities in such structures significantly increased. Eu(3+) can directly enter or be carried by the artificial ion carrier A23187 into plant cells through the calcium ion (Ca(2+)) channel and then partially resume the synthesis of amaranthin in the Amaranthus caudatus growing in the dark. Locations of rare earth elements La(3+) and Eu(3+) in all kinds of components of cytoplasmatic organelles were determined with transmission electron microscope, scanning electron microscope, and energy-dispersive X-ray microanalysis. The results of energy-dispersive X-ray microanalysis indicated that Eu(3+) and La(3+) can be absorbed into plant cells and bind to the membranes of protoplasm, chloroplast, mitochondrion, cytoplast, and karyon. These results provide experimental evidence that rare earth elements can be absorbed into plant cells, which would be the basis for interpreting physiological and biochemical effects of rare earth elements on plant cells. PMID:12663949

  20. Distribution Characteristics of Rare Earth Elements in Children's Scalp Hair from a Rare Earths Mining Area in Southern China

    Microsoft Academic Search

    Shi-Lu Tong; Wang-Zhao Zhu; Zhao-Hua Gao; Yu-Xiu Meng; Rui-Ling Peng; Guo-Cheng Lu

    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

  1. Rare earth element oxides for tracing sediment movement

    Microsoft Academic Search

    V. O. Polyakov; M. A. Nearing

    2004-01-01

    The development of soil conservation plans and evaluation of spatially distributed erosion models require knowledge of rates of soil loss and sedimentation on different landscape elements and slope positions. Characterization of soil erosion rates and patterns within watersheds is important for the understanding of erosion processes and landscape evolution. Experimental data that show spatial translocation of soil on slopes are

  2. Rare earth element mobility in the Roffna Gneiss, Switzerland

    Microsoft Academic Search

    Robert D. Vocke; Gilbert N. Hanson; Marc Griinenfelder

    1987-01-01

    The Roffna Gneiss, a deformed Hercynian granite porphyry within the Penninic nappes of eastern Switzerland, underwent extreme cataclasis with the progressive development of phengite towards the margins of the nappe under conditions of the glaucophane schist to greenschist facies. This resulted in the selective mobilization of major and trace elements over distances of 10's to 100's of meters and the

  3. RARE EARTH ELEMENT OXIDES FOR TRACING SEDIMENT MOVEMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of soil conservation plans and evaluation of spatially distributed erosion models require knowledge of rates of soil loss and sedimentation on different landscape elements and slope positions. Characterization of soil erosion rates and patterns within watersheds is important for the ...

  4. Geochemistry for Chemists.

    ERIC Educational Resources Information Center

    Hostettler, John D.

    1985-01-01

    A geochemistry course for chemists is described. Includes: (1) general course information; (2) subject matter covered; and (3) a consideration of the uses of geochemistry in a chemistry curriculum, including geochemical "real world" examples, geochemistry in general chemistry, and geochemistry as an elective. (JN)

  5. The variation of REE (rare earth elements) patterns in soil-grown plants: a new proxy for the source of rare earth elements and silicon in plants

    Microsoft Academic Search

    FengFu Fu; Tasuku Akagi; Sadayo Yabuki; Masaya Iwaki

    2001-01-01

    Rare earth elements (REEs) in five species of soil-grown plants (Taxodium japonicum, Populus sieboldii, Sasa nipponica, Thea sinensis and Vicia villosa) and in the soil on which each plant grew were determined with an inductively coupled plasma mass spectrometer (ICP-MS) in order to observe the variation in the distribution of REEs and to elucidate their source in soil-grown plants. The

  6. Rare-earth element distribution characteristics of biological chains in rare-earth element-high background regions and their implications

    Microsoft Academic Search

    Hui Zhang; Jia Feng; Weifang Zhu; Congqiang Liu; Dongsen Wu; Wenjiao Yang; Jianghong Gu

    2000-01-01

    The rare-earth element (REE) contents of water and vegetables from two typical REE-high background regions and a normal region\\u000a in Gannan, Jiangxi Province, indicated that the REE contents were significantly different from those of water and vegetables,\\u000a respectively. The average values are 0.03 mg\\/L and 0.11 mg\\/L REE for water from regions A and B. As the REE contents of

  7. Determination of rare earth elements in Camellia oleifera seeds from rare earth elements mining areas in Southern Jiangxi, China by ICP-MS

    Microsoft Academic Search

    Dingjian Cai; Yu-kui Rui

    For detection and analysis of the potential accumulation of rare earth elements (REE) in food products originating from REE\\u000a mining area the REE content of Camellia\\u000a oleifera seeds from these area was determined by ICP-MS; the results for limits of detection of REE (mostly lower than 3.00 ng\\/L)\\u000a and the relative standard deviation (1.97–11.7 %) for 10 REE demonstrate the significance of

  8. Laser photolysis of complexes of etioporphyrin I with rare-Earth elements

    Microsoft Academic Search

    V. E. Pyatosin; M. P. Tsvirko; K. N. Solov'ev; T. F. Kachura

    1981-01-01

    gate nonluminescent complexes also. We undertook an investigation of the spectra and kinetics of induced absorption in complexes of porphyrins with rare-earth elements with a nanosecond laser-photolysis unit. In the present communication, we present the results of an investigation of rare-earth complexes of etioporphyrin I. Excitation was carried out with the second harmonic of an LTI PCh-7 neodymium laser. A

  9. Sol-Gel synthesis of an optical silica glass doped with rare-earth elements

    Microsoft Academic Search

    N. N. Khimich; G. M. Berdichevskii; E. N. Poddenezhnyi; V. V. Golubkov; A. A. Boiko; V. M. Ken’ko; O. B. Evreinov; L. A. Koptelova

    2007-01-01

    An optical quality silica glass doped with Er3+, Yb3+ and Lu3+ ions is synthesized by the sol-gel method. Virtually unavoidable clusterization of rare-earth elements that occurs upon introduction\\u000a of lanthanide salts into a sol-gel system and leads to concentration quenching of luminescence of the glass is eliminated\\u000a through the use of rare-earth phosphate complexes that are chemically bound to the

  10. The provenance of Cretaceous to Quaternary sediments in the Tarfaya basin, SW Morocco: Evidence from trace element geochemistry and radiogenic Nd-Sr isotopes

    NASA Astrophysics Data System (ADS)

    Ali, Sajid; Stattegger, Karl; Garbe-Schönberg, Dieter; Frank, Martin; Kraft, Steffanie; Kuhnt, Wolfgang

    2014-02-01

    We present trace element compositions, rare earth elements (REEs) and radiogenic Nd-Sr isotope analyses of Cretaceous to recent sediments of the Tarfaya basin, SW Morocco, in order to identify tectonic setting, source rocks composition and sediments provenance. The results suggest that the sediments originate from heterogeneous source areas of the Reguibat Shield and the Mauritanides (West African Craton), as well as the western Anti-Atlas, which probably form the basement in this area. For interpreting the analyzed trace element results, we assume that elemental ratios such as La/Sc, Th/Sc, Cr/Th, Th/Co, La/Co and Eu/Eu? in the detrital silicate fraction of the sedimentary rocks behaved as a closed system during transport and cementation, which is justified by the consistency of all obtained results. The La/Y-Sc/Cr binary and La-Th-Sc ternary relationships suggest that the Tarfaya basin sediments were deposited in a passive margin setting. The trace element ratios of La/Sc, Th/Sc, Cr/Th and Th/Co indicate a felsic source. Moreover, chondrite-normalized REE patterns with light rare earth elements (LREE) enrichment, a flat heavy rare earth elements (HREE) and negative Eu anomalies can also be attributed to a felsic source for the Tarfaya basin sediments. The Nd isotope model ages (TDM = 2.0-2.2 Ga) of the Early Cretaceous sediments suggest that sediments were derived from the Eburnean terrain (Reguibat Shield). On the other hand, Late Cretaceous to Miocene--Pliocene sediments show younger model ages (TDM = 1.8 Ga, on average) indicating an origin from both the Reguibat Shield and the western Anti-Atlas. In contrast, the southernmost studied Sebkha Aridal section (Oligocene to Miocene-Pliocene) yields older provenance ages (TDM = 2.5-2.6 Ga) indicating that these sediments were dominantly derived from the Archean terrain of the Reguibat Shield.

  11. Mineralogical anomalies and their influences on elemental geochemistry of the main workable coal beds from the Dafang Coalfield, Guizhou, China

    USGS Publications Warehouse

    Dai, S.; Ren, D.; Li, D.; Chou, C.-L.; Luo, K.

    2006-01-01

    Mineralogy and geochemistry of the No. 11 Coal bed were investigated by using inductively-coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence (XRF), scanning electron microscopy equipped with energy-dispersive X-ray (SEM-EDX), sequential chemical extraction procedure (SCEP), and optical microscopy. The results show that the No. 11 Coal bed has very high contents of veined quartz (Vol. 11.4%) and veined ankerite (Vol. 10.2 %). The veined ankerite was generally coated by goethite and the veined quartz embraced chalcopyrite, sphalerite, and selenio-galena. In addition, a trace amount of kaolinite was filled in the veins. These seven minerals often occur in the same veins. The formation temperatures of the veined ankerite and quartz are 85??C and 180??C respectively, indicating their origins of iron-rich calcic and siliceous low-temperature hydrothermal fluids in different epigenetic periods. Studies have also found that the veined quartz probably formed earlier than the veined ankerite, and at least three distinct ankerite formation stages were observed by the ration of Ca/Sr and Fe/Mn of ankerite. The mineral formation from the early to late stage is in order of sulfide, quartz, kaolinite, ankerite, and goethite. The veined ankerite is the dominant source of Mn, Cu, Ni, Pb, and Zn, which are as high as 0.09%, 74.0 ??g/g, 33.6 ??g/g, 185 ??g/g, and 289 ??g/g in this coal seam, respectively. However, the veined quartz is the main carrier of Pd, Pt, and Ir, which are 1.57 ??g/g, 0.15 ??g/g, and 0.007 ??g/g in this coal seam, respectively. In addition, chalcopyrite, sphalerite, and selenio-galena of hydrothermal origin were determined in the veined quartz, and these three sulfide minerals are also important carriers of Cu, Zn and Pb in the No. 11 Coal bed.

  12. Vanadium oxide bronzes containing rare-earth elements

    SciTech Connect

    Volkov, V.L.; Zubkov, V.G.; Fedyukov, A.S.; Zainulin, Yu.G.

    1988-05-01

    We attempted to make phases having the general formula Ln/sub x/V/sub 2/O/sub 5/ (Ln = La, Eu, Yb) without success; the specimens usually consisted of three phases: the rare-earth orthovanadate LnVO/sub 4/, vanadium(V) oxide, and VO/sub 2/. To shift the process to give Ln/sub x/V/sub 2/O/sub 5/, heat treatment was applied to mixtures of the initial high-purity substances. The x-ray patterns were recorded with a DRON-UM1 apparatus with Cr K..cap alpha.. radiation and were processed by the Poroshok program. The IR spectra were recorded with UR-20 spectrometer with oil mulls.

  13. Petrology, major and trace element geochemistry, geochronology, and isotopic composition of granitic intrusions from the vicinity of the Bosumtwi impact crater, Ghana

    NASA Astrophysics Data System (ADS)

    Losiak, Anna; Schulz, Toni; Buchwaldt, Robert; Koeberl, Christian

    2013-09-01

    The Bosumtwi crater is 10.5 km in diameter, 1.07 Ma old, well preserved impact structure located in Ghana (centered at 06°30?N, 01°25?W). It was excavated in rocks of the Early Proterozoic Birimian Supergroup, part of the West African craton. Here, we present a full and detailed characterization of the three granitoid complexes and one mafic dike in the vicinity of the Bosumtwi crater in terms of petrology, major and trace element geochemistry, geochronology, and isotopic composition. This allows us to characterize magmatic evolution of the West African Craton in this area and better understand the geological framework and target rocks of the impact. This study shows that the similar composition (strongly peraluminous muscovite granites and granodiorites) and age (between 2092 ± 6 Ma and 2098 ± 6 Ma) of all granitic intrusions in the proximity of the Bosumtwi crater suggest that they are co-genetic. Granitoids were probably formed as a result of anatexis of TTGs (or rocks derived from them) at relatively low pressure and temperature. We propose that the intrusions from the Bosumtwi area are genetically related to the Banso granite occurring to the east of the crater and can be classified as basin-type, late-stage granitoids. Also a mafic dike located to the NE of the Bosumtwi crater seems to be genetically related to those felsic intrusions. Based on those findings a revised version of the geological map of the Bosumtwi crater area is proposed.

  14. Trace element geochemistry of the Jurassic coals in the Feke and Kozan (Adana) Areas, Eastern Taurides, Turkey

    SciTech Connect

    Kara-Gulbay, R.; Korkmaz, S. [Karadeniz Technical University, Trabzon (Turkey). Faculty of Engineering

    2009-07-01

    In this study, trace element and organic matter-trace element relation between Jurassic coals exposed in three different fields in the eastern Taurides were examined and their enrichment values with respect to upper crust values were calculated and the coal characteristics were also compared with world arithmetic means and those from the U.S. In comparison to the Feke and Kizilin coals, Pb, Zn, Ag, and Hg element contents of the Gedikli coals are considerably high; Ni, As, and Ge contents are moderately high; and Cr, Cu, Co, Cd, Sb, Ga, and Sn contents are slightly high. The element concentrations are very similar to those of other fields. In the Gedikli coals, Sr content is extremely low and Ba content is slightly low with respect to other fields. Re, Mo, U, V, and B element concentrations are different for each of three fields. The major element contents of the Feke, Gedikli, and Kizilin coals were correlated with world arithmetic means and average values of coals from the U.S. and Fe, K, Mg, and Na concentrations were found to be similar. Ti and Al contents of the world and USA coals are higher while Ca and Mn concentrations are lower. Considering trace element contents of the world and U.S. coals, Ba is considerably high, Cu and Zr are moderately high, and Ga, Rb, and Sc elements are slightly high. In comparison to world arithmetic means and U.S. coals, Sr content of the Feke and Kizilin coals are very high while those of the Gedikli coals are lower. For major and trace elements, factors of enrichment with respect to upper crust values were also calculated. The highest enrichment values were calculated for Ca and S. Except for Se and Rb, all other trace elements are enriched with respect to upper crust.

  15. Trace element geochemistry of Manilkara zapota (L.) P. Royen, fruit from winder, Balochistan, Pakistan in perspective of medical geology.

    PubMed

    Hamza, Salma; Naseem, Shahid; Bashir, Erum; Rizwani, Ghazala H; Hina, Bushra

    2013-07-01

    An integrated study of rocks, soils and fruits of Manilkara zapota (L.) (Sapotaceae) of Winder area have been carried out to elaborate trace elements relationship between them. The igneous rocks of the study area have elevated amount of certain trace elements, upon weathering these elements are concentrated in the soil of the area. The trace elements concentration in the soil were found in the range of 0.8-197 for Fe, 1.23-140 for Mn, 0.03-16.7 for Zn, 0.07-9.8 for Cr, 0.05-2.0 for Co, 0.52-13.3 for Ni, 0.03-8.8 for Cu, 0.08-10.55 for Pb and 0.13-1.8?g/g for Cd. The distribution pattern of elements in the rocks and soils reflected genetic affiliation. Promising elements of edible part of the fruit were Fe (14.17), Mn (1.49), Cr (2.96), Ni (1.13), Co (0.92), Cu (1.70) and Zn (1.02?g/g). The concentration of these elements in the fruits is above the optimum level of recommended dietary intake, probably due to this, disorder in the human health is suspected in the inhabitants of the area. PMID:23811462

  16. Contribution to the geochemistry of trace elements in the sediments of the Noun River and tributaries, western Cameroon.

    PubMed

    Njofang, C; Matschullat, J; Tchouankoué, J P; Amougou, A

    2007-09-15

    This study reports on the distribution of trace elements in the sediments of the Noun River valley. Two groups of trace elements have emerged based on their distribution and geochemical behaviour. The first group shows lower values whereas the second group aligns higher values. Elements like Al and Sr in one side and Zn, Zr in the other present concentrations statistically different from those of the rocks compared to other elements in trace analyzed (Cr, Ni, Ba, Co, Cu, Fe, Mn, V, As and Pb). The trace elements Al, Sr, Zr, Zn and Pb in the sediments of the Noun River show concentrations rather lower than those of the world. The average concentrations in elements C (3.72%), N (0.27%), S (0.05%) and of the ratios C/N (13.77) and N/S (5.29) reflect those resulting from the decomposition of the organic matter which derives from soils with very small concentrations in S. The Noun valley sediments are mostly of primary (quartz, microcline, plagioclase, orthoclase, ilmenite, anatase) and newly formed or secondary (kaolinite, gibbsite, hematite, goethite) minerals. This mineralogy and the overall low concentration of the studied trace elements, with Al, Fe, Ti and Mn as most abundant elements, is consistent with the local geology made up of the basic rocks (basalts, volcanic ash) and of the acid rocks (granites, gneiss). Overall the trace elements concentration and distribution suggest their geogene origin. Yet, this study is a first contribution of its kind towards the development of a baseline geochemical database essential for a sustainable and healthier Noun valley ecosystem. PMID:19090098

  17. Rare earths and other trace elements in Apollo 14 samples.

    NASA Technical Reports Server (NTRS)

    Helmke, P. A.; Haskin, L. A.; Korotev, R. L.; Ziege, K. E.

    1972-01-01

    REE and other trace elements have been determined in igneous rocks 14053, 14072, and 14310, in breccias 14063 and 14313, and in fines 14163. All materials analyzed have typical depletions of Eu except for feldspar fragments from the breccias and igneous fragments from 14063. Igneous rocks 14072 and 14053 have REE concentrations very similar to Apollo 12 basalts; 14310 has the highest REE concentrations yet observed for a large fragment of lunar basalt. The effects of crystallization of a basaltic liquid as a closed system on the concentrations of Sm and Eu in feldspar are considered. Small anorthositic fragments may have originated by simple crystallization from very highly differentiated basalt (KREEP) or by closed-system crystallization in a less differentiated starting material. Application of independent models of igneous differentiation to Sm and Eu in massive anorthosite 15415 and to Sm and Eu in lunar basalts suggests a common starting material with a ratio of concentrations of Sm and Eu about the same as that in chondrites and with concentrations of those elements about 15 times enriched over chondrites.

  18. Zircon trace element geochemistry: partitioning with garnet and the link between U–Pb ages and metamorphism

    Microsoft Academic Search

    Daniela Rubatto

    2002-01-01

    With the aim to link zircon composition with paragenesis and thus metamorphic conditions, zircons from eclogite- and granulite-facies rocks were analysed for trace elements using LA-ICP-MS and SHRIMP ion microprobe. Metamorphic zircons from these different settings display a large variation in trace element composition. In the granulites, zircon overgrowths formed in equilibrium with partial melt and are similar to magmatic

  19. Late Archaean mantle metasomatism below eastern Indian craton: Evidence from trace elements, REE geochemistry and Sr—Nd—O isotope systematics of ultramafic dykes

    Microsoft Academic Search

    A. Roy; A. Sarkar; S. Jeyakumar; S. K. Aggrawal; M. Ebihara; H. Satoh

    2004-01-01

    Trace, rare earth elements (REE), Rb-Sr, Sm-Nd and O isotope studies have been carried out on ultramafic (harzburgite and\\u000a lherzolite) dykes belonging to the newer dolerite dyke swarms of eastern Indian craton. The dyke swarms were earlier considered\\u000a to be the youngest mafic magmatic activity in this region having ages not older than middle to late Proterozoic. The study\\u000a indicates

  20. Provenance of glacial tills in Ong Valley, Antarctica, inferred from quartz cathodoluminescence imaging, zircon U/Pb dating, and trace element geochemistry

    NASA Astrophysics Data System (ADS)

    Edwards, K. L.; Padilla, A. J.; Evans, A.; Morgan, D. J.; Balco, G.; Putkonen, J.; Bibby, T.

    2014-12-01

    An issue for interpreting exposure ages using cosmogenic nuclides is prior exposure (inheritance), especially for stable nuclides such as Ne-21. In this study we examine the reliability of provenance as a possible tool for determining the degree to which inheritance is an issue for a given sample. We use zircon U/Pb ages, quartz cathodoluminescence imaging, and trace element geochemistry from Antarctic glacial drifts and compare these to zircon, quartz, and trace elements from local bedrock in order to determine the drifts' origins. This is potentially useful in Ong Valley in the Central Transantarctic Mountains, and likely elsewhere in Antarctica, as Antarctic glacial sediments are only derived either from sources that lie beneath the ice, where it likely had little prior exposure to cosmic rays, or from the relatively small amount of local, exposed bedrock, which would have inherited nuclides. Thus, sediment provenance is likely correlated with its inherited nuclide inventory. The bedrock of Ong Valley is composed of granite (Hope Granite, Granite Harbour Intrusives) and gneiss, and contains three glacial drifts. We collected samples from these three drifts and the surrounding bedrock. Cosmogenic nuclide dating using Ne-21 provides exposure ages for the quartz that can be used to constrain the timing of the glacier's retreat from the three sites. The accuracy of these three exposure ages depends on the prior (or inherited) exposure of the sediment and its sources. The use of the use of multiple methods for determining provenance allows us to compare the results and see if they reach the same conclusion. If cathodoluminescence imaging proves to be a reliable method for establishing provenance it would provide complementary information for cosmogenic nuclide dating, especially because quartz is significantly more abundant and we would be obtaining coupled provenance information and exposure ages from a single mineral.

  1. Petrogenesis of Archaean ultrabasic and basic volcanics: Evidence from rare earth elements

    Microsoft Academic Search

    Shen-Su Sun; Robert W. Nesbitt

    1978-01-01

    Rare earth element (REE) and major element data are presented on 44 Archaean samples which include spinifex textured ultramagnesian lavas (STPK) spinifex textured basalts (STB) and low MgO tholeiites. The samples come from the Yilgarn and Pilbara Blocks (W. Australia), Barberton (South Africa), Belingwe and Que Que (Rhodesia), Abitibi (Canada) and the 3.7 b.y. Isua Belt of Western Greenland. In

  2. Distribution of rare earth elements in crystalline bedrock groundwaters: Oslo and Bergen regions, Norway

    Microsoft Academic Search

    D. Banks; G. Hall; C. Reimann; U. Siewers

    1999-01-01

    One hundred and fifty Norwegian bedrock groundwater samples, from Bergen and from Vestfold (Oslofjord), have been analysed by ICP-MS techniques at two laboratories for a large suite of trace elements including rare earth elements (REEs) and Y. The bedrock lithologies include granites (dominated by the Permian Drammen Granite) and Permian latites\\/rhomb porphyries from Oslofjord, and Caledonian\\/Precambrian granitic and gneissic lithologies

  3. Calcium Isotopic Ratios and Rare Earth Element Abundances in Refractory Inclusions from Allende CV3 Chondrite

    Microsoft Academic Search

    Shichun Huang; Juraj Farkaš; Gang Yu; Michail I. Petaev; Stein B. Jacobsen

    Refractory inclusions in primitive meteorites are the oldest objects formed in the Solar System. They exhibit large mass-dependent isotopic effects in many elements, including Si, Mg and Ca, indicative of their complex origin. We report data for both mass-dependent (?) and mass-independent (?) Ca isotopic effects, and rare earth element (REE) abundances in six refractory inclusions from the Allende CV3

  4. Determination of rare-earth elements in Luna 16 regolith sample by chemical spectral method

    NASA Technical Reports Server (NTRS)

    Stroganova, N. S.; Ryabukhin, V. A.; Laktinova, N. V.; Ageyeva, L. V.; Galkina, I. P.; Gatinskaya, N. G.; Yermakov, A. N.; Karyakin, A. V.

    1974-01-01

    An analysis was made of regolith from layer A of the Luna 16 sample for rare earth elements, by a chemical spectral method. Chemical and ion exchange concentrations were used to determine the content of 12 elements and Y at the level 0.001 to 0.0001 percent with 10 to 15 percent reproducibility of the emission determination. Results within the limits of reproducibility agree with data obtained by mass spectra, activation, and X-ray fluorescent methods.

  5. Partitioning of rare earth elements between clinopyroxene and silicate melt Crystal-chemical controls

    Microsoft Academic Search

    Glenn A. Gaetani; Timothy L. Grove

    1995-01-01

    This study explores some of the effects of major element compositional variations on the partitioning of trivalent rare earth elements between high-Ca clinopyroxene and silicate melt. Experiments performed in the system CaO?MgO?A12O3?SiO2 at 1 atm pressure, over a small temperature range, differentiate crystal-chemical controls on mineral\\/melt partitioning from the effects of pressure and temperature. The experimental results demonstrate that the

  6. The Fate of Sulfur during Decompression Melting of Peridotite and Crystallization of Basalts - Implications for Sulfur Geochemistry of MORB and the Earth's Upper Mantle

    NASA Astrophysics Data System (ADS)

    Ding, S.; Dasgupta, R.

    2014-12-01

    Magmatism in mid-ocean ridges is the main pathway of sulfur (S) from the Earth's mantle to the surficial reservoir. MORB is generally considered sulfide saturated due to the positive correlation between S and FeOT concentration (e.g., [1]). However, most MORBs are differentiated, and both S content and sulfur concentration at sulfide saturation (SCSS) change with P, T, and magma composition (e.g., [2]). Therefore, it remains uncertain, from the MORB chemistry alone, whether mantle melts parental to MORB are sulfide saturated. In this study, we modeled the behavior of S during isentropic partial melting of a fertile peridotite using pMELTS [3] and an SCSS parameterization [4]. Our results show that during decompression melting, at a fixed mantle potential temperature, TP (e.g., 1300 °C), SCSS of aggregate melt first slightly increases then decreases at shallower depth with total variation <200 ppm. However, an increase of TP results in a significant increase of SCSS of primitive melts. Our model shows that at 15% melting (F), sulfide in the residue is exhausted for a mantle with <200 ppm S. The resulted sulfide-undersaturated partial melts contain <1000 ppm S and are 4-6 times enriched in Cu compared to the source. In order to compare our modeled results directly to the differentiated basalts, isobaric crystallization calculation was performed on 5, 10, and 15% aggregate melts. SCSS changes along liquid line of descent with a decrease in T and increase in FeOT. Comparison of S contents between the model results and MORB glasses [5] reveals that many MORBs derive from sulfide undersaturated melts. Further, for a TP of 1300-1350 °C and F of 10-15 wt.%, reproduction of self-consistent S, and Cu budget of many MORB glasses requires that S of their mantle source be ~25-200 ppm. We will discuss the interplay of TP, average F, and the conditions of differentiation to bracket the S geochemistry of MORB and MORB source mantle and develop similar systematics for OIBs and OIB source. References: [1] Le Roux et al. (2006) EPSL, 251, 209-231. [2] Baker and Moritti (2011) Rev. in Mineral. Geochem, 73, 167-213. [3] Ghiorso et al. (2002) Geochem. Geophy. Geosy. 3, 5. [4] Li and Ripley (2009) Econ. Geol. 104, 405-412. [5] Jenner and O'Neill (2012) Geochem. Geophy. Geosy. 13, 1.

  7. Composition of the earth's upper mantle. I - Siderophile trace elements in ultramafic nodules

    NASA Technical Reports Server (NTRS)

    Morgan, J. W.; Wandless, G. A.; Petrie, R. K.; Irving, A. J.

    1981-01-01

    The considered investigation is concerned with a reexamination of the question of the distribution of siderophile elements in the earth's upper mantle, taking into account a more unified data base which is now available. A comprehensive suite of ultramafic inclusions was collected as part of the Basaltic Volcanism Study Project and has been analyzed by instrument neutron activation analysis for major, minor, and some lithophile trace elements. In addition, 18 of these rocks and the important sheared garnet lherzolite PHN 1611 have been analyzed by means of radiochemical neutron activation analysis for 7 siderophile elements (Au, Ge, Ir, Ni, Os, Pd, and Re) and 9 volatile elements (Ag, Bi, Cd, In, Sb, Se, Te, Tl, and Zn). The siderophile element data reveal interesting inter-element correlations, which were not apparent from the compiled abundance tables of Ringwood and Kesson (1976) and Chou (1978).

  8. Radioluminescence and thermoluminescence of rare earth element and phosphorus-doped zircon

    SciTech Connect

    Karali, T.; Can, N.; Townsend, P.D.; Rowlands, A.P.; Hanchar, J.M.

    2000-06-01

    The radioluminescence and thermoluminescence spectra of synthetic zircon crystals doped with individual trivalent rare earth element (REE) ions (Pr, Sm, Eu, Gd, Dy, Ho, Er, and Yb) and P are reported in the temperature range 25 to 673 K. Although there is some intrinsic UV/blue emission from the host lattice, the dominant signals are from the rare-earth sites, with signals characteristic of the REE{sup 3+} states. The shapes of the glow curves are different for each dopant, and there are distinct differences between glow peak temperatures for different rare-earth lines of the same element. Within the overall set of signals there are indications of linear trends in which some glow peak temperatures vary as a function of the ionic size of the rare earth ions. The temperature shifts of the peaks are considerable, up to 200{degree}, and much larger than those cited in other rare-earth-doped crystals of LaF{sub 3} and Bi{sub 4}Ge{sub 3}O{sub 12}. The data clearly suggest that the rare-earth ions are active both in the trapping and luminescence steps, and hence the TL occurs within localized defect complexes that include REE{sup 3+} ions.

  9. Preprint of the paper "A Boundary Element Numerical Approach for Earthing Grid Computation"

    E-print Network

    Colominas, Ignasi

    of grounding systems, as well as distribution of potentials on the earth surface due to fault currents [1 in the margin of error [4]. A Boundary Element approach for the numerical computation of substation grounding formulation has been implemented in a speci#12;c Computer Aided Design system for grounding analysis developed

  10. Undecaprenyl Pyrophosphate Involvement in Susceptibility of Bacillus subtilis to Rare Earth Elements

    PubMed Central

    Ochi, Kozo

    2012-01-01

    The rare earth element scandium has weak antibacterial potency. We identified a mutation responsible for a scandium-resistant phenotype in Bacillus subtilis. This mutation was found within the uppS gene, which encodes undecaprenyl pyrophosphate synthase, and designated uppS86 (for the Thr-to-Ile amino acid substitution at residue 86 of undecaprenyl pyrophosphate synthase). The uppS86 mutation also gave rise to increased resistance to bacitracin, which prevents cell wall synthesis by inhibiting the dephosphorylation of undecaprenyl pyrophosphate, in addition to enhanced amylase production. Conversely, overexpression of the wild-type uppS gene resulted in increased susceptibilities to both scandium and bacitracin. Moreover, the mutant lacking undecaprenyl pyrophosphate phosphatase (BcrC) showed increased susceptibility to all rare earth elements tested. These results suggest that the accumulation of undecaprenyl pyrophosphate renders cells more susceptible to rare earth elements. The availability of undecaprenyl pyrophosphate may be an important determinant for susceptibility to rare earth elements, such as scandium. PMID:22904278

  11. Rare earth element behavior and Pb, Sr, Nd isotope systematics in a heavy metal contaminated soil

    Microsoft Academic Search

    Marc Steinmann; Peter Stille

    1997-01-01

    The aim of this study is to characterize the processes and phases which control migration and retention of rare earth elements (REE) in a heavy metal contaminated soil. In addition to concentration data, we used Pb, Sr and Nd isotopic compositions in order to distinguish between natural and anthropogenic trace metals and to characterize the phases leached away during the

  12. The rare earth element compositions of the Changjiang (Yangtze) and Huanghe (Yellow) river sediments

    E-print Network

    Yang, Shouye

    were analyzed to characterize their rare earth element (REE) compositions. Although REE concentrations samples and acid-leachable fractions have convex REE patterns and middle REE enrichments relative to upper is the primary control on REE composition, and weathering processes play a minor role. Grain size exerts some

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

    E-print Network

    environmental concerns, have created a great demand for the rare earth elements (REE), and focused considerable of the world's largest econom- ic 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

  14. Rare earth element systematics of fossil bone revealed by LA-ICPMS analysis

    E-print Network

    Schöne, Bernd R.

    November 2012 Abstract Intra-bone rare earth element (REE) fractionation trends were studied by LA-ICPMS analysis to put constraints on (1) the mechanisms controlling REE fractionation within fossil bones; (2) the relative timing of REE uptake in various parts of fossil bone and (3) the origin of REE in fossil bones. We

  15. Fractionation of rare-earth elements in plants during experimental growth in varied clay substrates

    Microsoft Academic Search

    Khadija Semhi; Sam Chaudhuri; Norbert Clauer

    2009-01-01

    The distribution and content of rare-earth elements (REEs) were determined in two radish species, the cultivated Raphanus sativus and the wild Raphanus raphanistrum, that were grown under laboratory-controlled conditions, in three substrates consisting of illite for one and two smectite substrates for the others, with the two smectite substrates being characterised by different porosities. The plants were split into leaves

  16. EXTRACTION OF RARE-EARTH ELEMENTS FROM NITRIC SOLUTIONS BY PHOSPHORYL-CONTAINING PODANDS

    Microsoft Academic Search

    A. N. Turanov; V. K. Karandashev; V. E. Baulin

    1999-01-01

    The extraction of microquantities of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y from HNO3 solutions by phosphoryl-containing podands of various structures has been studied. It has been found that the maximum extraction of rare earth elements is exhibited by reagents containing one ether oxygen atom in the molecule, bound to diphenylphosphoryl

  17. Sources of rare earth elements in Appin Group limestones, Dalradian, north-east Scotland

    Microsoft Academic Search

    C. W. Thomas

    1993-01-01

    Summary Rare earth elements (REE) have been determined in 15 samples from three metamorphosed limestone units of the Appin Group of the Dalradian of north-east Scotland. Total REE contents range from about 7 to about 50 ppm and the light REEs are slightly enriched compared with REE in the North American Shale Composite (NASC). In the more impure limestones, the

  18. Rare earth element variations resulting from inversion of pigeonite and subsolidus reequilibration in lunar ferroan anorthosites

    Microsoft Academic Search

    Odette B. James; Christine Floss; James J. McGee

    2002-01-01

    We present results of a secondary ion mass spectrometry study of the rare earth elements (REEs) in the minerals of two samples of lunar ferroan anorthosite, and the results are applicable to studies of REEs in all igneous rocks, no matter what their planet of origin. Our pyroxene analyses are used to determine solid-solid REE distribution coefficients (D = CREE

  19. Rare-earth element distributions in volcanic rocks from Archean greenstone belts

    Microsoft Academic Search

    Kent C. Condie; W. R. A. Baragar

    1974-01-01

    Rare-earth element distributions in Archean volcanic rocks from the South Pass (Wyoming), Yellowknife (NW Canada) and Abitibi (Quebec) greenstone belts and from the Upper Fig Tree Group of the Barberton (S. Africa) greenstone belt reveal two distinct types of Archean volcanism. One type, herein referred to as the arc-type, is characterized by flat (or slightly enriched) REE distributions in tho

  20. Cerium redox cycles and rare earth elements in the Sargasso Sea

    Microsoft Academic Search

    E. R. Sholkovitz; D. L. Schneider

    1991-01-01

    Two profiles of the rare earth elements (REEs) are reported for the upper water column of the Sargasso Sea. The trivalent-only REEs have remarkably constant concentrations in the upper 500m of an April 1989 profile and in the upper 200m of a May 1989 profile. In contrast, Ce concentrations decrease smoothly with increasing depth. In April 1989 Ce decreases from

  1. Rare earth elements as indicators of different marine depositional environments in chert and shale

    Microsoft Academic Search

    Richard W. Murray; D. L. Jones; M. R. Bruchholtz ten Brink; David C. Gerlach; G. Price Russ III

    1990-01-01

    Differences in rare earth element (REE) relative fractionations and total abundances in marine cherts and shales reflect the depositional location of the sediments. Based on cerium anomaly (Ce\\/Ce*) and total REE abundance (ΣREE) variations preserved in interbedded chert and shale sequences of the Franciscan assemblage, the Claremont Formation, and the Monterey Formation of coastal California, we can resolve three depositional

  2. Rare earth element partitioning between clinopyroxene and silicate liquid at moderate to high pressure

    Microsoft Academic Search

    T. H. Green; N. J. Pearson

    1985-01-01

    Experimental determination of over seventy sets of clinopyroxene\\/silicate liquid (glass) partitition coefficients (D) for four rare earth elements (REE — La, Sm, Ho, Lu) in a range of REE-enriched natural rock compositions (basalt, basaltic andesite, andesite and rhyodacite) demonstrate a convex upward pattern, favouring the heavy REE (Ho, Lu) and markedly discriminating against the light REE (La). These patterns are

  3. Rare earth elements in soil and in soil-grown plants

    Microsoft Academic Search

    A. Wyttenbach; V. Furrer; P. Schleppi; L. Tobler

    1998-01-01

    Concentrations of the rare earth elements (REEs) La, Ce, Nd, Sm, Eu, Gd, Tb, Yb and Lu were determined in leaves of 6 plant species (Norway spruce, silver fir, maple, ivy, blackberry, and wood fern), and in pertinent soils and soil extracts, also taken from the same site. The distribution of the individual REEs in plants showed little or no

  4. Island weathering: river sources of rare earth elements to the Western Pacific Ocean

    Microsoft Academic Search

    E. r. Sholkovitz; H. Elderfield; R. Szymczak; K. Casey

    1999-01-01

    This paper focuses on two of the largest rivers and estuaries of Papua New Guinea (PNG), the Fly and Sepik and explores the degree to which river input and estuarine reactions affect the rare earth element (REE) composition of surface sea water in the western tropical Pacific Ocean. The dissolved phases of the Fly and Sepik River waters have striking

  5. Determination of the rare-earth elements in geological materials by inductively coupled plasma mass spectrometry

    Microsoft Academic Search

    Frederick E. Lichte; Allen L. Meier; James G. Crock

    1987-01-01

    A method of analysis of geological materials for the determination of the rare-earth elements using the inductively coupled plasma mass spectrometric technique (ICP-MS) has been developed. Instrumental parameters and factors affecting analytical results have been first studied and then optimized. Samples are analyzed directly following an acid digestion, without the need for separation or preconcentration with limits of detection of

  6. The partitioning of rare earth elements between garnet and liquid at high pressures: Preliminary experiments

    Microsoft Academic Search

    N. Shimizu; I. Kushiro

    1975-01-01

    Preliminary experiments were made to determine the partition coefficients of rare earth elements between garnet and liquid at 30 kb and 1275°C in the system diopside (30 wt%) -pyrope(70%) -water. REE were added to the system by titration at concentration levels in the range of natural basalts. The phases were separated by differential dissolution technique (DDT) and analized for REE

  7. Rare earth element patterns: A tool for understanding processes in remediation of acid mine drainage

    Microsoft Academic Search

    Dirk Merten; Jörn Geletneky; Hans Bergmann; Götz Haferburg; Erika Kothe; Georg Büchel

    2005-01-01

    The distribution of rare earth elements (REE) was applied to study processes in remediation of acid mine drainage (AMD). The concentration of total REE is up to 3mgl?1 in AMD. Normalization of REE concentrations in seepage and surface waters to Post-Archean Australian Shale (PAAS) shows strong enrichment of heavy REE. For the case of the studied AMD REE patterns are

  8. Distribution of rare earth elements among chloroplast components of hyperaccumulator Dicranopteris dichotoma

    Microsoft Academic Search

    Xiao-ping Wang; Xiao-quan Shan; Shu-zhen Zhang; Bei Wen

    2003-01-01

    .  A rare earth element (REE) hyperaccumulator, Dicranopteris dichotoma, that accumulates more than 0.1% REEs dry leaf mass has been discovered in southern China. The different components of chloroplast were isolated and the concentration of REEs in each component was determined by ICP-MS. The experimental data indicated that about 8% of total leaf REEs was present in the chloroplast of Dicranopteris

  9. Concentrations of rare earth elements in sediments, mussels and fish from a Danish marine environment, Lillebaelt

    Microsoft Academic Search

    I. Drabaek; P. Eichner; L. Rasmussen

    1987-01-01

    Results for the content of the rare earth elements (REE), La, Ce, Nd, Sm, Eu, Tb, Yb and Lu in sediments, mussels and fish are presented for an area polluted by REE. The REE are emitted with the process waste water stream from a fertilizer production plant. The method of analysis has been INAA. An attempt to combine the INAA

  10. Certified reference materials for the quality control of rare earth element determinations in the environment

    Microsoft Academic Search

    Ph Quevauviller

    2002-01-01

    The European Commission (through its BCR activity) is active in organising interlaboratory studies, the final aim of which is the production of Certified Reference Materials (CRMs) representing the best of the state of the art in given analytical sectors. As a response to needs expressed by laboratories for environmental reference materials certified for rare earth elements (REEs), a programme was

  11. Rare earth elements leaching from Chadormalu apatite concentrate: Laboratory studies and regression predictions

    Microsoft Academic Search

    Esmaeil Jorjani; Amir Hossein Bagherieh; Saeed Chehreh Chelgani

    2011-01-01

    The extraction of rare earth elements from apatite concentrate of Chadormalu plant of Iran was studied with the dissolution of ore in nitric acid. The parameters of acidity: 60%, solid to liquid ratio: 30%, leaching time: 30 minute, agitation rate: 200 rpm, temperature: 60 °C and particle size (d80): 50 microns were determined as the optimum operational conditions. The recoveries

  12. Effect of rare earth elements on growth and antioxidant metabo- lism in Lemna minor L

    Microsoft Academic Search

    Maria Paola; Costantino Paciolla; Luigi d'Aquino; Massimo Morgan; Franca Tommasi

    Lemna minor is frequently used in bioremediation processes to remove nutrients and contaminants from waste water. In this work the response of L. minor to treatments with lanthanum nitrate and with a mix of several light rare earth elements (REE) nitrates was investigated. Preliminary results indicate that L. minor shows an overall good tolerance to the presence of REE in

  13. Accumulation and uptake of light rare earth elements in a hyperaccumulator Dicropteris dichotoma

    Microsoft Academic Search

    Xiaoquan Shan; Haiou Wang; Shuzhen Zhang; Hanfa Zhou; Yan Zheng; Hong Yu; Bei Wen

    2003-01-01

    Dicropteris dichotoma, a natural perennial fern, grows in acidic soil in southern China. It hyperaccumulates several light rare earth elements La, Ce, Pr and Nd (LREEs) up to about 0.7% of its dry leaf biomass. Through electron microscopic and X-ray microanalyses, LREEs deposits were observed in the cell wall, intercellular space, plasmalemma, vesicles and vacuoles of the root endodermis and

  14. Rare Earth Element Fluxes in Diverse Soils and Their Absorption by Coconut Palm

    Microsoft Academic Search

    P. A. Wahid; N. V. Kamalam; R. Krishna Prabhu; J. K. Sekhar; S. Vijayalakshmi; T. R. Mahalingam; C. E. Ajith Kumar

    2003-01-01

    The pattern of uptake of six rare earth elements (REEs) [lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), and gadolinium (Gd)] by coconut palm (Cocos nucifera L.) from three types of soils varying widely in their chemical characteristics and monazite content were studied through soil and plant tissue analysis employing ICP?MS method. Absorption of the REEs by the

  15. Vibration spectra and physicochemical properties of sesquisulfides of rare earth elements

    Microsoft Academic Search

    S. A. Kutolin; R. N. Samoilova; M. N. Korotkevich

    1972-01-01

    The vibration spectra of sesquisulfides of rare earth elements were investigated in the IR region. A set of lattice vibrations were interpreted by multiphonon approximation, analogous to the method described in connection with wurtzite lattice vibrations for cadmium sulfide. We compared the experimental and the theoretical changes in the effective fraction of the dielectric permeability with the frequency by a

  16. Content of rare earth elements in Salvia miltiorrhiza bunge from different areas

    Microsoft Academic Search

    Xiangsheng LIU; He ZHANG; Zhiyong ZHANG; Xian'en LI; Xuewei HAN; Yanping WU

    2010-01-01

    Salvia miltiorrhiza bunge (SMB) has been widely used as a traditional Chinese medicine for a long time, and today more and more attention has been paid to the effective components in Chinese traditional medicine, especially to rare earth elements (REEs). 14 kinds of REEs in SMB from different areas were analyzed by the methods of ICP-MS. The results showed that

  17. Abundance of rare earth elements in rice paddy soils from three regions of Sri Lanka

    Microsoft Academic Search

    Rohana Chandrajith; Chandrasekara Bandara Dissanayake; Heinz Jürgen Tobschall

    2004-01-01

    Very few studies deal with the rare earth element (REE) content within paddy soil systems. This paper presents, for the first time, the distribution of REEs in paddy soils from three different regions in Sri Lanka. Seventy samples from the Kalutara and Kandy regions located in the Wet Zone and Anuradhapura region in the Dry Zone were selected for this

  18. Total concentrations and bioavailability of rare-earth elements in latesol in Hainan Province, China

    Microsoft Academic Search

    Weihuang Zhu; Yuangen Yang; Fengchang Wu; Hua Bi; Qiang Liu

    2006-01-01

    Total and bioavailable concentrations of rare earth elements (REEs) in the latesol of Hainan Province, China, were measured by ICP-MS, and the distribution characteristics of REEs were discussed in various latesol profiles. The results show that the total concentrations of REEs were higher than the average statistical data of the whole China. The correlation coefficients between the total and bioavailable

  19. Differences in Behavior among the Chlorides of Seven Rare Earth Elements Administered Intravenously to Rats

    Microsoft Academic Search

    Yumiko Nakamura; Yukari Tsumura; Yasuhide Tonogai; Tadashi Shibata; Yoshio Ito

    1997-01-01

    Differences in behavior among the chlorides of seven rare earth elements (REEs)—yttrium (Y), cerium (Ce), and praseodymium (Pr) (light REEs); europium (Eu) and dysprosium (Dy) (medium REEs); ytterbium (Yb) and lutetium (Lu) (heavy REEs)—were investigated through intravenous administration of the REEs to rats. (1) Distributions of REEs and mineral concentrations in the organs on Day 1 were investigated at low

  20. Rare earth elements in the sediments of Lake Baikal Lawrence M. Och a

    E-print Network

    Wehrli, Bernhard

    Rare earth elements in the sediments of Lake Baikal Lawrence M. Och a , Beat Müller a, , Adrian Baikal sediments Iron and manganese cycling Early diagenesis Lake Baikal is the deepest and probably of the REE chemistry in Lake Baikal and its catchment area and more specifically REE distribution in five 11

  1. SEDIMENT REWORKING AND TRANSPORT IN EASTERN LAKE SUPERIOR: IN SITU RARE EARTH ELEMENT TRACER STUDIES

    EPA Science Inventory

    A rare earth element (REE) tracer pellet was deployed at the floor of the Ile Parisienne basin of eastern Lake Superior to measure representative sediment reworking and transport processes in the benthic boundary layer of the prnfundal Great Lakes. Samarium oxide, a high neutron-...

  2. The aquatic chemistry of rare earth elements in rivers and estuaries

    Microsoft Academic Search

    Edward R. Sholkovitz

    1995-01-01

    Laboratory experiments were carried out to determine how pH, colloids and salinity control the fractionation of rare earth elements (REEs) in river and estuarine waters. By using natural waters as the reaction media (river water from the Connecticut, Hudson and Mississippi Rivers) geochemical reactions can be studied in isolation from the large temporal and spatial variability inherent in river and

  3. Project EARTH-12-SHELL3: Isotopic and elemental records of ocean redox conditions

    E-print Network

    Henderson, Gideon

    as micronutrients (both processes are associated with isotope fractionation). This project aims to investigate whichProject EARTH-12-SHELL3: Isotopic and elemental records of ocean redox conditions Supervisors: Hugh is funded by Shell and is part of a larger Shell-supported research project on metal isotopes in source

  4. Infiltration water organic matter and trace element geochemistry in a semi-arid karst environment: implications for speleothem paleoclimatology

    NASA Astrophysics Data System (ADS)

    Rutlidge, H.; Baker, A.; Marjo, C.; Andersen, M. S.; Graham, P. W.; Cuthbert, M. O.; Rau, G. C.; Roshan, H.; Markowska, M.; Kelloway, S.

    2013-12-01

    A series of short-term field infiltration experiments were conducted at Wellington caves, NSW, Australia, a semi-arid karst environment. Coupled with laboratory soil leaching experiments, our results, highlight important implications for the interpretation of paleoclimate records in stalagmites in these regions. Cave dripwater was collected from two adjacent drip sites that activated during the infiltration experiment. The trace element and fluorescent dissolved organic matter (fDOM) content were analyzed. Principal component analysis showed that the variation in the dataset could be explained by two components: soil-derived and bedrock-derived. The soil component was identified based on its correlation with fDOM. Barium, magnesium, copper and nickel were also associated with the soil component. The bedrock component comprised silicon and the elements associated with carbonate such as calcium, strontium, magnesium. These results were confirmed by the soil leaching experiments. In addition to the soil leaching experiments, the site was characterized by the elemental and mineralogy analysis of soil and limestone collected from above the cave. Using the iTRAX core scanner, sediment/limestone cores collected down to 30m from the site were also analyzed and similar elemental correlations were investigated. In this semi-arid environment, barium and magnesium, elements normally bedrock associated, show different behavior. Barium is derived from the soil and magnesium is derived from both the bedrock and soil. An important observation is that magnesium, previously reported as a proxy for effective rainfall, may not be suitable tracer in semi-arid environments, due to the additional contribution from the soil. However this study has identified the potential of barium in stalagmites as a soil tracer, and silicon as a bedrock tracer, in our semi-arid environments. We present our preliminary results of LA ICPMS trace element analysis of stalagmites collected from the same site and deposited over the last 100 years. We compare the stalagmite proxy records to our laboratory and field calibration and historical climate records.

  5. RARE EARTH ELEMENTS IN FLY ASHES AS POTENTIAL INDICATORS OF ANTHROPOGENIC SOIL CONTAMINATION

    SciTech Connect

    Mattigod, Shas V.

    2003-08-01

    Studies of rare earth element (REE) content of disposed fly ashes and their potential mobility were neglected for decades because these elements were believed to be environmentally benign. A number of recent studies have now shown that REE may pose a long-term risk to the biosphere. Therefore, there is a critical need to study the REE concentrations in fly ash and their potential mobilization and dispersal upon disposal in the environment. We analyzed the REE content of bulk, size fractionated, and density separated fractions of three fly ash samples derived from combustion of sub bituminous coals from the western United States and found that the concentrations of these elements in bulk ashes were within the range typical of fly ashes derived from coals from the North American continent. The concentrations of light rare earth elements (LREE) such as La, Ce, and Nd, however, tended towards the higher end of the concentration range whereas, the concentrations of middle rare earth elements (MREE) (Sm and Eu) and heavy rare earth elements (HREE) (Lu) were closer to the lower end of the observed range for North American fly ashes. The concentrations of REE did not show any significant enrichment with decreasing particle size, this is typical of nonvolatile lithophilic element behavior during the combustion process. The lithophilic nature of REE was also confirmed by their concentrations in heavy density fractions of these fly ashes being on average about two times more enriched than the concentrations in the light density fractions. Shale normalized average of REE concentrations of fly ashes and coals revealed significant positive anomalies for Eu and Dy. Because of these distinctive positive anomalies of Eu and Dy, we believe that fly ash contamination of soils can be fingerprinted and distinguished from other sources of anthropogenic REE inputs in to the environment.

  6. Mutual influence of elements during coprecipitation. Cocrystallization of rare-earth elements under conditions for the formation of double sulfates of alkali and alkaline-earth metals

    SciTech Connect

    Tsizin, G.I.; Kalinchenko, N.B.; Malofeeva, G.I.; Marov, I.N.; Tobelko, K.I.; Urusov, V.S.

    1985-04-20

    This paper studies the coprecipitation of rare-earth metals under conditions for the crystallization of double salts in other sulfate systems, as well as the possibility of the employment of these double salts for the selective preconcentration of rare-earth metals from solutions of complex composition. The influence of electrolytes containing and not containing an element which may act as a charge compensator during isomorphous substitution was studied. Data are presented on the coprecipitation of cerium (III) and lutetium under the conditions for the crystallization of the double salt K/sub 2/SR(SO/sub 4/)/sub 2/ in the presence of LiC1 and LiNO/sub 3/, as well as HC1 and HNO/sub 3/.

  7. Trace element geochemistry of zircons from mineralizing and non-mineralizing igneous rocks related to gold ores at Yanacocha, Peru

    NASA Astrophysics Data System (ADS)

    Koleszar, A. M.; Dilles, J. H.; Kent, A. J.; Wooden, J. L.

    2012-12-01

    Zircons record important details about the evolution of magmatic systems, are relatively insensitive to alteration, and have been used to investigate the geochemistry, temperature, and oxidation state of volcanic and plutonic system. We examine zircons that span 6-7 m.y. of calc-alkaline volcanic activity in the Yanacocha district of northern Peru, where dacitic intrusions are associated with high-sulfidation gold deposits. The 14.5-8.4 Ma Yanacocha Volcanics include cogenetic lavas and pyroclastic rocks and are underlain by the andesites and dacites of the Calipuy Group, the oldest Cenozoic rocks in the region. We present data for magmatic zircons from the Cerro Fraile dacitic pyroclastics (15.5-15.1 Ma) of the Calipuy Group, and multiple eruptive units within the younger Yanacocha Volcanics: the Atazaico Andesite (14.5-13.3 Ma), the Quilish Dacite (~14-12 Ma), the Azufre Andesite (12.1-11.6 Ma), the San Jose Ignimbrite (11.5-11.2 Ma), and the Coriwachay Dacite (11.1-8.4 Ma). Epithermal high sulfidation (alunite-bearing) gold deposits are associated with the dacite intrusions of the Coriwachay and Quilish Dacites. Zircons from the non-mineralizing rocks typically have lower Hf concentrations and record Ti-in-zircon temperatures that are ~100°C hotter than zircons from the mineralizing intrusions. Temperatures recorded by zircons from the mineralizing intrusions are remarkably similar to those of the underlying Cerro Fraile dacite pyroclastics, but the zircons discussed here generally record SHRIMP-RG 206Pb/238U ages within error of previously published Ar-Ar eruption ages (eliminating antecrystic or xenocrystic origins). These observations suggest that zircons in the mineralizing intrusions form after greater extents of crystallization (and thus record elevated Hf concentrations and lower temperatures) than do zircons in the non-mineralized deposits. Unlike zircons from mineralized units associated with the porphyry Cu(Mo) deposits in Yerington, Nevada, which generally have Eu/Eu* ratios approaching 1 (i.e., Eu-anomalies that decrease in magnitude) with increasing Hf (and thus increasing crystallization), zircons associated with mineralized deposits in the Coriwachay and Quilish intrusions at Yanacocha typically have Eu-anomalies that are highly variable but do not vary systematically during magma evolution. These Eu/Eu* versus Hf trends are inconsistent with observations from the porphyry Cu-Mo(Au) deposit at El Salvador, Chile, where zircons from all porphyry intrusions have Eu-anomalies that become systematically more negative during magma evolution but with highest Eu/Eu* occurring in mineralized intrusions. We explore a variety of scenarios to explain the Eu/Eu* systematics of zircons from Yanacocha, including changes to the magmatic oxidation state as a consequence of anhydrite breakdown and progressive degassing.

  8. Medical geochemistry of tropical environments

    NASA Astrophysics Data System (ADS)

    Dissanayake, C. B.; Chandrajith, Rohana

    1999-10-01

    Geochemically, tropical environments are unique. This uniqueness stems from the fact that these terrains are continuously subjected to extreme rainfall and drought with resulting strong geochemical fractionation of elements. This characteristic geochemical partitioning results in either severe depletion of elements or accumulation to toxic levels. In both these situations, the effect on plant, animal and human health is marked. Medical geochemistry involves the study of the relationships between the geochemistry of the environment in which we live and the health of the population living in this particular domain. Interestingly, the relationships between geochemistry and health are most marked in the tropical countries, which coincidentally are among the poorest in the world. The very heavy dependence on the immediate environment for sustainable living in these lands enables the medical geochemist to observe correlations between particular geochemical provinces and the incidence of certain diseases unique to these terrains. The aetiology of diseases such as dental and skeletal fluorosis, iodine deficiency disorders, diseases of humans and animals caused by mineral imbalances among others, lie clearly in the geochemical environment. The study of the chemistry of the soils, water and stream sediments in relation to the incidence of geographically distributed diseases in the tropics has not only opened up new frontiers in multidisciplinary research, but has offered new challenges to the medical profession to seriously focus attention on the emerging field of medical geochemistry with the collaboration of geochemists and epidemiologists.

  9. Distribution coefficients of 60 elements on TODGA resin: application to Ca, Lu, Hf, U and Th isotope geochemistry.

    PubMed

    Pourmand, Ali; Dauphas, Nicolas

    2010-05-15

    Batch equilibration experiments are conducted to measure the distribution coefficients (K(d)) of a large number of elements in nitric, nitric plus hydrofluoric, and hydrochloric acids on Eichrom TODGA extraction chromatography resin. The K(d)s are used to devise a multi-element extraction scheme for high-precision elemental and isotopic analyses of Ca, Hf, Lu, Th and U in geological materials, using high-purity lithium metaborate (LiBO(2)) flux fusion that allows rapid digestion of even the most refractory materials. The fusion melt, dissolved in nitric acid, is directly loaded to a TODGA cartridge on a vacuum chamber for elemental separation. An Ln-Spec cartridge is used in tandem with TODGA for Lu purification. The entire procedure, from flux digestion to preparation for isotopic analysis, can be completed in a day. The accuracy of the proposed technique is tested by measuring the concentrations of Ca (standard bracketing), Hf, Lu, Th and U (isotope dilution), and the isotopic composition of Hf in geostandards (USNM3529, BCR-2, BHVO-1, AGV-1 and AGV-2). All measurements are in excellent agreement with recommended literature values, demonstrating the effectiveness of the proposed analytical procedure and the versatility of TODGA resin. PMID:20298848

  10. The environmental geochemistry of trace elements and naturally radionuclides in a coal gangue brick-making plant.

    PubMed

    Zhou, Chuncai; Liu, Guijian; Cheng, Siwei; Fang, Ting; Lam, Paul K S

    2014-01-01

    An investigation focused on the transformation and distribution behaviors of trace elements and natural radionuclides around a coal gangue brick plant was conducted. Simultaneous sampling of coal gangue, brick, fly ash and flue gas were implemented. Soil, soybean and earthworm samples around the brick plant were also collected for comprehensive ecological assessment. During the firing process, trace elements were released and redistributed in the brick, fly ash and the flue gas. Elements can be divided into two groups according to their releasing characteristics, high volatile elements (release ratio higher than 30%) are represented by Cd, Cu, Hg, Pb, Se and Sn, which emitted mainly in flue gas that would travel and deposit at the northeast and southwest direction around the brick plant. Cadmium, Ni and Pb are bio-accumulated in the soybean grown on the study area, which indicates potential health impacts in case of human consumption. The high activity of natural radionuclides in the atmosphere around the plant as well as in the made-up bricks will increase the health risk of respiratory system. PMID:25164252

  11. Minor and trace element geochemistry of volcanic rocks dredged from the Galapagos spreading center: role of crystal fractionation and mantle heterogeneity.

    USGS Publications Warehouse

    Clague, D.A.; Frey, F.A.; Thompson, G.; Rindge, S.

    1981-01-01

    A wide range of rock types (abyssal tholeiite, Fe-Ti-rich basalt, andesite, and rhyodacite) were dredged from near 95oW and 85oW on the Galapagos spreading center. Computer modeling of major element compositions has shown that these rocks could be derived from common parental magmas by successive degrees of fractional crystallization. However, the P2O5/K2O ratio implies distinct mantle source compositions for the two areas. These source regions also have different rare earth element (REE) abundance patterns. The sequence of fractionated lavas differs for the two areas and indicates earlier fractionation of apatite and titanomagnetite in the lavas from 95oW. The mantle source regions for these two areas are interpreted to be depleted in incompatible (and volatile?) elements, although the source region beneath 95oW is less severely depleted in La and K. -Authors

  12. Behaviour of zirconium, niobium, yttrium and the rare earth elements in the Thor Lake rare-metal

    E-print Network

    Behaviour of zirconium, niobium, yttrium and the rare earth elements in the Thor Lake rare-metal © Emma Rebecca Sheard, 2010 #12;i ABSTRACT The Thor Lake rare-metal (Zr, Nb, Y, REE, Ta, Be, Ga) deposit and the heavy rare earth elements in the world. Much of the potentially economic mineralization was concentrated

  13. Study of rare earth element effect on microstructures and mechanical properties of an Al-Cu-Mg-Si cast alloy

    Microsoft Academic Search

    Weiwei WAN; Jianmin HAN; Weijing LI; Jinhua WANG

    2006-01-01

    The improvements of microstructures and properties of a high strength aluminum cast alloy were studied. The effects of rare earth elements on the microstructures and mechanical properties of the high strength cast alloy Al-Cu-Mg-Si were investigated. The result shows that the addition of rare earth elements can change the microstructures in refining the grain size of the alloy and making

  14. Adsorption of rare earth elements onto bacterial cell walls and its implication for REE sorption onto natural microbial mats

    E-print Network

    Adsorption of rare earth elements onto bacterial cell walls and its implication for REE sorption of rare earth elements (REE) onto the cell walls of Bacillus subtilis (a gram-positive bacterium concentrations. The distribution coefficients of REE between the bacterial cell surface and water showed

  15. Rare Earth Element sorption by basaltic rock: experimental data and modeling results using the "Generalised Composite approach".

    E-print Network

    Paris-Sud XI, Université de

    Rare Earth Element sorption by basaltic rock: experimental data and modeling results using Email address : emmanuel.tertre@univ-poitiers.fr Keywords: sorption, lanthanides, basalt, surface.1016/j.gca.2007.12.015 #12;Abstract Sorption of the 14 Rare Earth Elements (REE) by basaltic rock

  16. ?-decay of neutron-rich Z?60 nuclei and the origin of rare earth elements

    SciTech Connect

    Wu, J. [RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan and School of Physics and State key Laboratory of Nuclear Physics and Technology, Peking University (China); Nishimura, S.; Lorusso, G.; Baba, H.; Doornenbal, P.; Isobe, T.; Söderström, P. A.; Sakurai, H. [RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Xu, Z. Y. [Department of Physics, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, 113-0033 Tokyo (Japan); Browne, F. [School of Computing Engineering and Mathematics, University of Brighton (United Kingdom); Daido, R.; Fang, Y. F.; Yagi, A.; Nishibata, H.; Odahara, A.; Yamamoto, T. [Department of Physics, Osaka University, Machikaneyama-machi 1-1, Osaka 560-0043 Toyonaka (Japan); Ideguchi, E.; Aoi, N.; Tanaka, M. [Research Center for Nuclear Physics, Osaka University (Japan); Collaboration: EURICA Collaboration; and others

    2014-05-02

    A large fraction of the rare-earth elements observed in the solar system is produced in the astrophysical rapid neutron capture process (r-process). However, current stellar models cannot completely explain the relative abundance of these elements partially because of nuclear physics uncertainties. To address this problem, a ?-decay spectroscopy experiment was performed at RI Beam Factory (RIBF) at RIKEN, aimed at studying a wide range of very neutron-rich nuclei with Z?60 that are progenitors of the rare-earth elements with mass number A?460. The experiment provides a test of nuclear models as well as experimental inputs for r-process calculations. This contribution presents the experimental setup and some preliminary results of the experiment.

  17. A hybrid boundary element-finite element approach to modeling plane wave 3D electromagnetic induction responses in the Earth

    NASA Astrophysics Data System (ADS)

    Ren, Zhengyong; Kalscheuer, Thomas; Greenhalgh, Stewart; Maurer, Hansruedi

    2014-02-01

    A novel hybrid boundary element-finite element scheme which is accelerated by an adaptive multi-level fast multipole algorithm is presented to simulate 3D plane wave electromagnetic induction responses in the Earth. The remarkable advantages of this novel scheme are the complete removal of the volume discretization of the air space and the capability of simulating large-scale complicated geo-electromagnetic induction problems. To achieve this goal, first the Galerkin edge-based finite-element method (FEM) using unstructured meshes is adopted to solve the electric field differential equation in the heterogeneous Earth, where arbitrary distributions of conductivity, magnetic permeability and dielectric permittivity are allowed for. Second, the point collocation boundary-element method (BEM) is used to solve a surface integral formula in terms of the reduced electrical vector potential on the arbitrarily shaped air-Earth interface. Third, to avoid explicit storage of the system matrix arising from large-scale problems and to reduce the horrendous time complexity of the product of the system matrix with an initial vector of unknowns, the adaptive multilevel fast multipole method is applied. This leads to a matrix-free form suitable for the application of iterative solvers. Furthermore, a highly sparse problem-dependent preconditioner is developed to significantly reduce the number of iterations used by the iterative solvers. The efficacy of the presented hybrid scheme is verified on two synthetic examples against different numerical techniques such as goal-oriented adaptive finite-element methods. Numerical experiments show that at low frequencies, where the quasi-static approximation is applicable, standard FEM methods prove to be superior to our hybrid BEM-FEM solutions in terms of computational time, because the FEM method requires only a coarse discretization of the air domain and offers an advantageous sparsity of the system matrix. At radio-magnetotelluric frequencies of a few hundred kHz, the hybrid BEM-FEM scheme outperforms the FEM method, because it avoids explicit storage of the system matrices as well as dense volume discretization of the air domain required by FEM methods at high frequencies. In summary, to the best of our knowledge, this study is the first attempt at completely removing the air space for large scale complicated electromagnetic induction modeling in the Earth.

  18. Mineralogy, major and trace element geochemistry of riverbed sediments in the headwaters of the Yangtze, Tongtian River and Jinsha River

    Microsoft Academic Search

    Weihua Wu; Shijun Xu; Huayu Lu; Jiedong Yang; Hongwei Yin; Wen Liu

    2011-01-01

    We collected riverbed sediments of the headwaters of the Yangtze River (Chumaer River, Tuotuo River, Gaerqu River and Buqu River), Tongtian River and Jinsha River (HTJR) flowing on the eastern Tibetan Plateau and analyzed their mineralogical features, major and trace element contents. The results show: (i) very poor correlations of Na2O, K2O, CaO, Ba, and Sr to SiO2, LREE to

  19. [Effect of rare earth elements on the seedling ratio of crops].

    PubMed

    Zhang, Z; Chang, J; Wang, C; Chai, S; Han, X; Li, R

    2001-06-01

    The effects of rare earth elements(REEs) on the relative seedling ratio of three crops(rice, rape and soybean) in three soil(red soil, yellow fluvo-aquic soil and yellow cinnamon soil) were studied according to OECD method, and the LC50 were obtained. Toxicity effect of REEs on rice was minimum among the crops tested. The toxicity on crops in yellow cinnamon soil was lower, whereas on soybean in yellow fluvo-aquic soil and on rape in red earth were higher. PMID:11758421

  20. Osmium Isotope Constraints on the Origin of Highly Siderophile Elements in the Earth's Primitive Upper Mantle

    NASA Astrophysics Data System (ADS)

    Walker, R. J.; Meisel, T.; Morgan, J. W.

    1996-03-01

    Using negative thermal ionization mass spectrometry (NTIMS), Re and Os abundances were determined by isotope dilution, and 187Os/188Os ratios were measured in a variety of terrestrial upper mantle xenoliths, and also ordinary, enstatite and carbonceous chondrites. Our objective is to precisely constrain the Os isotopic composition of the Earth's primitive upper mantle (PUM) and compare it with the Re-Os systematics of the different chondrite classes. Ultimately, these results should provide us with a better understanding of the relative abundances of highly siderophile elements added to the Earth by late accretion, and how their abundances were modified by subsequent processes.

  1. Geochemistry of mafic rocks from the Coto Block, Zambales ophiolite, Philippines: trace element evidence for two stages of crustal growth

    NASA Astrophysics Data System (ADS)

    Geary, E. E.; Kay, R. W.; Reynolds, J. C.; Kay, S. M.

    1989-10-01

    Slightly to pervasively metamorphosed basaltic, diabasic and gabbroic rocks from the central eastern (Coto Block) portion of the Zambales ophiolite and fresh basalts from the Mariana Trough provide new evidence than the Coto Block did not form in a simple, evolved back-arc basin setting. Although the majority of the Zambales basalts and diabases have slight LREE depletions [ ( {La}/{Sm}) ch < 1 ], REE abundances 4-15 × chondrites, and magmatic concentrations of Sr Y. Hf, Th and TiO 2 similar to back-arc spreading center basalts (N-MORB), other data, including bimodal Cr and Ni abundances and wide ranges in some incompatible element ratios (e.g., ( {La}/{Ta}) n = 0.2-21.0 ) are not typical geochemical characteristics of basalts dredged from modern back-arc basins. Furthermore, comparison of the Zambales trace element data to fresh basalts from the Mariana Trough and other ocean basins shows that such geochemical differences are not the result of low grade, sub-seafloor metamorphism. Synthesis of these geochemical findings with the currently available geological data indicates that the Coto Block of the Zambales ophiolite has experienced a two-stage crustal history. During the initial stage, dominantly N-MORB type ocean crust was formed at a large or back-arc basin spreading center but soon thereafter Coto Block crust was chemically modified by incipient island arc magmatism, most probably in a proto-forearc setting.

  2. Flat rare earth element patterns as an indicator of cumulate processes in the Lesser Qinling carbonatites, China

    Microsoft Academic Search

    Cheng Xu; Ian H. Campbell; Charlotte M. Allen; Zhilong Huang; Liang Qi; Huan Zhang; Guishan Zhang

    2007-01-01

    The Lesser Qinling carbonatite dykes are mainly composed of calcites. They are characterized by unusually high heavy rare earth element concentrations (HREE; e.g. Yb>30 ppm) and flat to weakly light rare earth element (LREE) enriched chondrite-normalized patterns (La\\/Ybn=1.0–5.5), which is in marked contrast with all other published carbonatite data. The trace element contents of calcite crystals were measured in situ by

  3. Structural Responses and Finite Element Modeling of Hakka Tulou Rammed Earth Structures

    NASA Astrophysics Data System (ADS)

    Sranislawski, Daniel

    Hakka Tulous are rammed earth structures that have survived the effects of aging and natural elements upwards of even over a thousand years. These structures have housed the Hakka people of the Fujian Province, China in natural yet modern housing that has provided benefits over newer building materials. The key building material, rammed earth, which is used for the walls of the Hakka Tulou structures, has provided structural stability along with thermal comfort to the respective inhabitants of the Hakka Tulous. Through material testing and analysis this study has examined how the Tulou structures have maintained their structural stability while also providing thermal comfort. Reports of self healing cracks in the rammed earth walls were also analyzed for their validity in this study. The study has found that although the story of the self healing crack cannot be validated, there is reason to believe that with the existence of lime, some type of autogenous healing could occur on a small scale. The study has also found, through the use of nondestructive testing, that both the internal wooden systems (flooring, roof, and column support) and the rammed earth walls, are still structurally sound. Also, rammed earth's high thermal mass along with the use of sufficient shading has allowed for a delay release of heat energy from the walls of the Tulous, thus providing thermal comfort that can be felt during both night and day temperatures. The Hakka Tulou structures have been found to resist destruction from natural disasters such as strong earthquakes even when more modern construction has not. Through finite element modeling, this study has shown that the high volume of rammed earth used in the construction of the Hakka Tulous helps dissipate lateral force energy into much lower stresses for the rammed earth wall. This absorption of lateral force energy allows the rammed earth structures to survive even the strongest of earthquakes experienced in the region. The Hakka Tulou, if rated by the LEED green building certification program, would earn the highest certification as this rammed earth construction has offered efficient living for hundreds of years. As historic as these rammed earth structures are, they present an environmentally friendly option to structures of the future.

  4. Petrogenesis of Late Permian sodic metagranitoids in southeastern Korea: SHRIMP zircon geochronology and elemental and Nd-Hf isotope geochemistry

    NASA Astrophysics Data System (ADS)

    Cheong, Chang-sik; Kim, Namhoon; Kim, Jeongmin; Yi, Keewook; Jeong, Youn-Joong; Park, Chan-Soo; Li, Huai-kun; Cho, Moonsup

    2014-12-01

    One of the striking tectonomagmatic features recently found in southeastern Korea is the occurrence of ca. 250 Ma high-silica adakite. Sodic metagranitoids mainly consisting of tonalitic-trondhjemitic-granodioritic gneisses occur in the Andong-Cheongsong area adjacent to the Yeongdeok adakite site. To investigate temporal and petrogenetic relationships of these orthogneisses with the adakite, we conducted SHRIMP zircon U-Pb dating as well as elemental and Nd-Hf isotopic analyses. Zircon core ages of the orthogneisses (ca. 262-251 Ma) confirm the widespread occurrence of arc-related Late Permian magmatism in southeastern Korea. The Late Triassic (ca. 230 Ma) zircon overgrowths reflect a thermal overprint probably related to the initiation of another subduction system. The analyzed orthogneisses have major element compositions comparable to the Phanerozoic adakites and Archean TTG suite, such as high SiO2 (58.7-65.5 wt.%) and Al2O3 (17.1-19.1 wt.%) contents and Na2O/K2O ratios (1.83-4.95). However, their moderate Sr/Y (35-43) and La/Yb (14-53) ratios and negative Eu anomalies (Eu/Eu* = 0.75-0.95) are incompatible with the key features reported from the Yeongdeok adakite. Moreover, initial whole-rock ?Nd (-7.9 to -3.3) and zircon ?Hf (-0.3 ± 2.4) values of the orthogneisses negate a direct derivation from the subducted slab. Our elemental and Nd-Hf isotopic data collectively suggest that the protoliths of the tonalitic-trondhjemitic-granodioritic gneisses were generated by partial melting of mafic lower crust at depths shallower than the garnet stability field. Our Nd and Hf model ages of the gneisses, together with those previously reported from the Mesozoic granitoids indicate a selective involvement of young source materials along the margin of the Yeongnam massif. The Hf isotopic compositions of zircons from a trondhjemitic gneiss attest to the involvement of primitive melts during their crystallization. The ridge subduction and consequent development of a slab window may have facilitated partial melting of the subducted oceanic lithosphere and the lower crust.

  5. Trace and Rare-Earth Element Geochemistry of the Karalar (Gazipafla—Antalya) Barite-Galena Deposits, Southern Turkey

    Microsoft Academic Search

    GÜLCAN BOZKAYA; AHMET GÖKÇE; Nadir Toprak; Element Jeokimyas; Güney Türkiye

    2004-01-01

    The Karalar barite-galena deposits are typical examples of carbonate-hosted barite-galena deposits that occur widely in the central Taurides. Recent mining activity has been concentrated in the Büyük and Boyal›k mine areas. The mineralisation occurs as ore veins along fault zones and as ore-filled breccia zones along the strongly deformed lower walls of limestone blocks in the Permian limestones of the

  6. Metallogenic epoch of the Jiapigou gold belt, Jilin Province, China: Constrains from rare earth element, fluid inclusion geochemistry and geochronology

    NASA Astrophysics Data System (ADS)

    Huang, Zhixin; Yuan, Wanming; Wang, Changming; Liu, Xiangwei; Xu, Xiaotong; Yang, Liya

    2012-12-01

    The Jiapigou gold belt is located on the northern margin of the North China Craton, and is one of the most important gold-mining and production regions in the circum-Pacific metallogenic zone. Research has been conducted in this area since the 1960s, however, the timing of the gold mineralisation is still unresolved, and an ideal metallogenic model has not been well established. To address these questions, a systematic geological, geochemical and geochronological investigation was conducted. The study revealed that (i) the gold-bearing quartz veins can be divided into two groups, earlier and later gold-bearing quartz veins according to their occurrence and the geochemical characteristics, (ii) the geochemical characteristics of the ore bodies, while similar to granite, are clearly different from the altered rock, and (iii) the geochemical characteristics of the later gold-bearing quartz veins have more similarity to the altered rock than the earlier gold-bearing quartz veins do. Therefore, we conclude that two independent stages of metallogenesis within the Jiapigou gold deposit area are related to magmatic activity in the Palaeoproterozoic and the Yanshanian stage of the Mesozoic, that the ore-forming fluids are mainly of magmatic origin, and that magma contamination by the altered rock was stronger in the Mesozoic. Zircon LA-ICP-MS U-Pb data show that the age of the Palaeoproterozoic granite is ~2426.0 Ma and that of the Mesozoic granite is ~166.2 Ma; these ages can be interpreted as the maximum ages of the two periods of gold mineralisation. In addition to investigating the geotectonic and regional structure of the Jiapigou gold belt, this study also proposes that the WNW-trending zone of gold mineralisation is a result of a magmatic event within the basement in the early Palaeoproterozoic, and that large-scale sinistral strike-slip displacements of the Huifahe and Liangjiang Faults in the late Middle Triassic (Yanshanian epoch) controlled the later tectono-magmatic event and the NNE-ENE-trending zone of gold mineralisation.

  7. Assessment of groundwater dynamics by applying rare earth elements and stable isotopes &ndash; the case of the Tiberias Basin, Jordan Valley.

    NASA Astrophysics Data System (ADS)

    Siebert, Christian; Möller, Peter; Rödiger, Tino; Al-Raggad, Marwan; Magri, Fabien

    2015-04-01

    The Tiberias basin, situated in the northern part of the Jordan-Dead Sea Transform Valley, is hydraulically connected to the surrounding aquifers of Cretaceous to Cenozoic age. As a result of the local erosion base, the basin hosts Lake Tiberias, recharged mainly by the Upper Jordan River and by fresh groundwater from the Galilee and Golan Heights. However, variably ascending deep-seated brines enhance the chlorinity of the lake to about 250-280 mg/l. In addition to these hot brines, also hot fresh waters emerge on surface, particularly to both sides of the Yarmouk gorge, SE of the basin. Investigation of rare earth element patterns and stable isotopes of water and sulfur, in combination with major elements reveal, that the gorge acts at least partially as a water divide between north and south with enhanced hydraulic conductivity along its axis. Although there are no geological evidences given, we suppose a swarm of hydraulic active fractures/faults parallel to the Lower Yarmouk gorge axis, which force the upward movement of hot fluids, as also suggested by numerical modeling. Additionally, these faults may channel SW-oriented groundwater flow, which has its origin in the Syrian Hauran Plateau. Although exercised in the Tiberias Basin, the application of trace and major element geochemistry in combination with stable isotopes allows analyzing (supra-) regional groundwater movements. This method is even more relevant in areas with either limited access to recharge areas or boreholes along proposed flow-paths and particularly in areas suffering from data scarcity and poor infrastructure.

  8. Ultra-trace rare earth element analysis of geochemical reference samples using a recycling nebulization system with a disposable spray chamber by inductively coupled plasma-mass spectrometry

    SciTech Connect

    Chen, Z. [Geological Survey of Canada, Ottawa, Ontario (Canada); Fryer, B.J. [Univ. of Windsor, Ontario (Canada); Longerich, H.P. [Memorial Univ. of Newfoundland, St. John`s (Canada)

    1994-12-31

    In recent years, the precise and accurate determination of rare earth elements (REEs) in a range of rock types has became increasingly important. Interpretation of the REE geochemistry of igneous and metamorphic rocks and minerals is a prerequisite for the development of many petrogenetic models. Inductively coupled plasma-mass spectrometry (ICP-MS) is a multi-element analytical method having detection limits across the whole mass range which are superior to most conventional techniques, particularly for heavy elements. However, there are samples in which the REE concentrations are below the detection limits (0.01-0.1 ppm) of whole rock procedures (1) in which samples are prepared at 0.5 g rock per kg solution (0.1 g per 200 g solution). A procedure, such as ion exchange, which increases the concentration of the REE`s while maintaining the total dissolved solids at less then 0.1% is required. In this study, 15 ultra-trace rare earth elements have been determined in 5 international geochemical reference samples at ultra-trace levels, PCC-1 (USGS), AL-I (GIT-IWG), FK-N (ANRT), NBS70a and NBS99a, using a recycling nebulization system with a disposable spray chamber by inductively coupled plasma-mass spectrometry (2), after preconcentrating the REEs from a 100 mg sample using cation exchange. Samples were dissolved, and a REE separate was obtained using 10 ml of cation exchange resin in a quartz column. Major elements were eluted using a 1.13 M HNO{sub 3}-0.63 M HCI solution. The REE were collected using 8 M HNO{sub 3}. The solution containing the REE`s was evaporated to dryness, the residue dissolved in HNO{sub 3}, and diluted to a final weight of 2 g using 0.2 M HNO{sub 3}. Solid limits of detection are 0.01-1 ppb. Precision, accuracy and sample heterogeneity are addressed.

  9. The effect of rare earth elements on the texture and formability of asymmetrically rolled magnesium sheet

    SciTech Connect

    Alderman, Dr. Martyn [Magnesium Elektron North America; Cavin, Odis Burl [ORNL; Davis, Dr. Bruce [Magnesium Elektron North America; Muralidharan, Govindarajan [ORNL; Muth, Thomas R [ORNL; Peter, William H [ORNL; Randman, David [Magnesium Elektron North America; Watkins, Thomas R [ORNL

    2011-01-01

    The lack of formability is a serious issue when considering magnesium alloys for various applications. Standard symmetric rolling introduces a strong basal texture that decreases the formability; however, asymmetric rolling has been put forward as a possible route to produce sheet with weaker texture and greater ductility. It has also been shown in recent work that weaker textures can be produced through the addition of rare earth elements to magnesium alloys. Therefore, this study has been carried out to investigate the effect of rare earth additions on the texture changes during asymmetric rolling. Two alloys have been used, AZ31B and ZEK100. The effect that the rare earth additions have on the texture of asymmetrically rolled sheet and the subsequent changes in formability will be discussed.

  10. Composition of the earth's upper mantle. II - Volatile trace elements in ultramafic xenoliths

    NASA Technical Reports Server (NTRS)

    Morgan, J. W.; Wandless, G. A.; Petrie, R. K.; Irving, A. J.

    1980-01-01

    Radiochemical neutron activation analysis was used to determine the nine volatile elements Ag, Bi, Cd, In, Sb, Se, Te, Tl, and Zn in 19 ultramafic rocks, consisting mainly of spinel and garnet lherzolites. A sheared garnet lherzolite, PHN 1611, may approximate undepleted mantle material and tends to have a higher volatile element content than the depleted mantle material represented by spinel lherzolites. Comparisons of continental basalts with PHN 1611 and of oceanic ridge basalts with spinel lherzolites show similar basalt: source material partition factors for eight of the nine volatile elements, Sb being the exception. The strong depletion of Te and Se in the mantle, relative to lithophile elements of similar volatility, suggests that 97% of the earth's S, Se and Te may be in the outer core.

  11. Using mineral trace element geochemistry to track magma processes in a "big tank" magma chamber: a laser ablation ICP-MS study of hornblende and augite

    NASA Astrophysics Data System (ADS)

    Coint, N.; Barnes, C. G.; Barnes, M. A.; Yoshinobu, A. S.

    2011-12-01

    Processes in magma chambers have been the subject of many discussions. Incremental emplacement models, supported by U-Pb zircon geochronology, preclude mixing, fractional crystallization and assimilation as chamber-wide processes. However, low-velocity seismic anomalies interpreted as partially molten areas in the crust, voluminous dacitic ignimbrites, and field evidence for crystal accumulation argue for large volumes of crystal-rich mush in the crust. In this study we use the trace element composition of liquidus phases augite and hornblende in the Wooley Creek batholith (WCb), Klamath Mountains, northern California, to reconstruct the geochemical history of the batholith. The WCb is a tilted pluton emplaced between 160 and 155 Ma. The lower WCb ranges from 2-pyroxene gabbro to hornblende tonalite. Variations in the texture and the proportions of hornblende and pyroxene suggest that the lower part was emplaced as several magma batches that reached hornblende stability at different temperatures and times. Augite crystals are normally zoned, with variable Cr (200-3000 ppm) and Ti (1000-4000 ppm) concentrations. Eu anomalies get progressively larger toward the rims, suggesting an evolution of individual melt batches by simple fractional crystallization. The central part of the pluton is mainly hornblende biotite quartz-diorite. Mafic enclaves and syn-plutonic dikes are abundant. Pyroxenes is rarely preserved in that part of the pluton. The upper WCb ranges from hornblende biotite quartz diorite to hornblende biotite granite. Bulk rock major element geochemical trends are consistent with upward differentiation of a single, unified magma batch. This interpretation is supported by homogenous trace element compositions of hornblende throughout the upper part of the pluton. Dacitic roof dikes contain hornblende phenocrysts identical to those in the upper WCb, indicating that the mush present in the upper WCb was eruptible. Two-pyroxene andesitic roof dikes are common and were interpreted as originating from the lower WCb. Oscillatory trace element zoning of augite plus low Cr (<1000 ppm) and high Ti (>3000 ppm) concentrations suggest that the dikes were derived from the central WCb, where evidence of replenishment and mingling is widespread. Thus, the lower and central parts of the pluton were emplaced as multiple, distinct magma batches. In contrast, the upper part of the pluton can be explained as (1)several batches of internally homogeneous magma emplaced at different times, with successively more evolved magma emplaced toward the top, or (2) evolution from a single large magma volume ('big tank') that could have been emplaced incrementally or as one batch. Existence of an upper 'big tank' is consistent with the lack of internal contacts, the presence of coherent geochemical trends and the presence of dacitic roof dikes compositionally identical to the upper part of the WCb. This study shows that mineral trace element geochemistry is a powerful tool in deciphering the size and evolution of magma batches within crystallized plutons.

  12. Symmetric charge-transfer cross sections of IIIa rare-earth-metal elements

    SciTech Connect

    Hashida, Masaki; Sakabe, Shuji; Izawa, Yasukazu [ARCBS, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan) and Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo, Kyoto 606-8502 (Japan); Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871 (Japan) and Institute for Laser Technology, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2011-03-15

    Symmetric charge-transfer cross sections of IIIa rare-earth-metal elements (Sc, Y, and Gd) in the impact energy range of 30 to 1000 eV were measured for the first time. The experiments were performed with a crossed-beam apparatus that featured primary ion production by photoionization with a tunable dye laser. Comparing the cross sections of IIIa rare-earth-metal elements ({sigma}{sub Sc}, {sigma}{sub Y}, and {sigma}{sub Gd}) with those of alkali metals or helium {sigma}{sub 0}, we found that {sigma}{sub 0{approx_equal}{sigma}Sc}<{sigma}{sub Y}<{sigma}{sub Gd{approx_equal}}2{sigma}{sub 0}at an impact energy of 1000 eV.

  13. Extraction of rare-earth elements from nitric solutions by phosphoryl-containing podands

    SciTech Connect

    Turanov, A.N.; Karandashev, V.K.; Baulin, V.E.

    1999-11-01

    The extraction of microquantities of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y from HNO{sub 3} solutions by phosphoryl-containing podands of various structures has been studied.. It has been found that the maximum extraction of rare earth elements is exhibited by reagents containing one ether oxygen atom in the molecule, bound to diphenylphosphoryl or ditolylphosphoryl groups by methylene and o-phenylene fragments. The structure of these reagents is best suited for the polydentate coordination of the ligand and the conditions of a chelate complex formation. The effect of HNO{sub 3} concentration in the aqueous phase and that of the nature of an organic diluent on the extraction of rare earth elements and Y are considered. Stoichiometric of the extracted complexes has been determined and the extraction constants calculated.

  14. Study of the influence of the rare-earth elements on the properties of lead iodide

    NASA Astrophysics Data System (ADS)

    Matuchova, M.; Zdansky, K.; Zavadil, J.; Danilewsky, A.; Riesz, F.; Hassan, M. A. S.; Alexiew, D.; Kral, R.

    2009-07-01

    Lead iodide (PbI 2) shows excellent electronic properties for detection of ionizing radiation. We report the introduction of rare-earth elements and other elements as admixtures during synthesis to study their influence on the quality of single crystals. Synthesized material as well as single crystals have been characterized by measurements of electrical resistivity and low-temperature photo luminescence and index of refraction. The structural quality with respect to polytypes was analysed by electron back scatter diffraction. Makyoh topography was applied for surface studies.

  15. Bishop tuff revisited: new rare Earth element data consistent with crystal fractionation.

    PubMed

    Cameron, K L

    1984-06-22

    The Bishop Tuff of eastern California is the type example of a high-silica rhyolite that, according to Hildreth, supposedly evolved by liquid-state differentiation. New analyses establish that the Bishop Tuff "earlyllate" rare earth element trend reported by Hildreth mimics the relations between groundmass glasses and whole rocks for allanite-bearing pumice. Differences in elemental concentrations between whole rock and groundmass are the result of phenocryst precipitation; thus the data of Hildreth are precisely those expected to result from crystal fractionation. PMID:17837193

  16. The effect of mining and related activities on the sediment trace element geochemistry of the Spokane River Basin, Washington, USA

    USGS Publications Warehouse

    Grosbois, C.A.; Horowitz, A.J.; Smith, J.J.; Elrick, K.A.

    2002-01-01

    Surface sediments in the Spokane River Basin are enriched in Pb, Zn, As, Cd, Sb, and Hg relative to local background levels. Maximum enrichment occurs in the Upper Spokane River in close proximity to Lake Coeur d'Alene. On average, enrichment decreases downstream. Subsurface sediments also are enriched in Pb, Zn, As, Cd, Sb, and Hg relative to background levels. Enrichment began between 1900 and 1920 in the middle of the basin; this is contemporaneous with similar findings in Lake Coeur d'Alene (the upstream source of the Spokane River), as well as the completion of Long Lake Dam (1913). In the most downstream part of the basin, enrichment began between 1930 and 1940. This temporal shift may reflect the latter's greater distance from the Coeur d'Alene River Basin, the presumptive source of the enriched trace elements, but is more likely the result of the completion of Grand Coulee Dam (1934-1941) which backed up the Spokane River, and elevated water levels by about 30 m in the most downstream part of the basin.

  17. Rare earth elements in waters from the albitite-bearing granodiorites of Central Sardinia, Italy

    Microsoft Academic Search

    Riccardo Biddau; Rosa Cidu; Franco Frau

    2002-01-01

    With the aim of contributing to the knowledge of the geochemical behaviour and mobility of the rare earth element (REE) in the natural water systems, the ground and surface waters of the Ottana–Orani area (Central Sardinia, Italy) were sampled. The study area consists of albititic bodies included in Hercynian granodiorites. The waters have pH in the range of 6.0–8.6, total

  18. Abundances of the fourteen rare-earth elements, scandium, and yttrium in meteoritic and terrestrial matter

    Microsoft Academic Search

    R. A. Schmitt; R. H. Smith; J. E. Lasch; A. W. Mosen; D. A. Olehy; J. Vasilevskis

    1963-01-01

    Abundances and isotopic ratios have been determined for the fourteen rare-earth elements (REE) (Pm excluded) plus Sc and Y by neutron-activation analysis in nineteen meteorites and in three terrestrial specimens. The meteorites investigated included eleven chondrites (1 carbonaceous, 2 pigeonitic, 2 hypersthenic, 3 bronzitic and 3 enstatitic), two calcium-rich and three calcium-poor achondrites, one mesosiderite and two iron meteorites; the

  19. Effect of temperature on the extraction of rare earth elements by alkylammonium salts

    Microsoft Academic Search

    V. V. Proyaev; A. A. Kopyrin; V. V. Shokin

    2009-01-01

    The extraction of rare earth elements in the cerium subgroup by tri-n-octylammonium nitrates in the temperature range 283-328°K is discussed. The effects of the temperature dependence of the distribution coefficients on the nature of the extracted metal, the nature and concentration of the salting out agents, and additions of complexone to the aqueous phase were studied. In the majority of

  20. Extraction of rare-earth elements from nitric acid solutions with bis(dioctylphosphinylmethyl)phosphinic acid

    Microsoft Academic Search

    A. N. Turanov; V. K. Karandashev; A. N. Yarkevich; Z. V. Safronova

    2006-01-01

    The distribution of microamounts of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y nitrates between aqueous\\u000a HNO3 solutions and solutions of bis(dioctylphosphinylmethyl)phosphinic acid in organic diluents was studied. The stoichiometry\\u000a of the extractable complexes was determined, and the diluent effect on the efficiency of extraction of rare-earth elements\\u000a from nitric acid solutions

  1. Extraction of rare-earth and transplutonium elements with dibutyl hydrogen phosphate in m -nitrobenzotrifluoride

    Microsoft Academic Search

    S. A. Rodionov; A. N. Viznyi; V. M. Esimantovskii; B. Ya. Zilberman

    2008-01-01

    The extraction of rare-earth (REE) and transplutonium (TPE) elements, with Ce, Eu, and Am as examples, from aqueous HNO3 with dibutyl hydrogen phosphate (HDBP) in m-nitrobenzotrifluoride (MNBTF) was studied. The diluent effect on the Eu and Am extraction with dibutyl hydrogen phosphate\\u000a was examined at various HNO3 concentrations in the aqueous phase. Based on the data obtained, a mechanism of

  2. Supercritical fluid extraction of rare earth elements from luminescent material in waste fluorescent lamps

    Microsoft Academic Search

    Ryosuke Shimizu; Kayo Sawada; Youichi Enokida; Ichiro Yamamoto

    2005-01-01

    Rare earth elements were extracted from luminescent material in waste fluorescent lamps using supercritical carbon dioxide (SF-CO2) containing tri-n-butyl phosphate (TBP) complexes with HNO3 and H2O. The determined Y, Eu, La, Ce and Tb in the employed luminescent material were 29.6, 2.3, 10.6, 5.0 and 2.6wt.%, respectively. Aqueous droplets were generated in an extraction experiment from a reaction with metal

  3. Extraction of rare earth elements by high molecular weight amines from nitric acid solutions

    Microsoft Academic Search

    M. S. Milyukova; N. S. Varezhkina; B. F. Myasoedov

    1986-01-01

    Extraction of trivalent rare earth elements by a high molecular weight primary amine \\/decylamine\\/ from 0.5–3M nitric acid solutions, containing potassium phosphotungstate \\/K10P2W17O61\\/, has been investigated. The effect of nitric acid and potassium phosphotungstate concentration of the organic solvent, and lanthanides ionic radii upon distribution coefficients has been studied. It has been established that decylamine solutions in chloroform can be

  4. Rare earth element distribution in some hydrothermal minerals: evidence for crystallographic control

    Microsoft Academic Search

    John W. Morgan; Gregory A. Wandless

    1980-01-01

    Rare earth element (REE) abundances were measured by neutron activation analysis in anhydrite (CaSO 4 ), barite (BaSO 4 ), siderite (FeCO 3 ) 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

  5. Behaviour of rare earth elements during submarine weathering of tholeiitic basalt

    Microsoft Academic Search

    John N. Ludden; Geoffrey Thompson

    1978-01-01

    DREDGED oceanic basalts and those sampled by deep-ocean drilling have commonly undergone some weathering with subsequent changes in their chemical composition1-7. The rare-earth elements (REE) La-Lu are generally considered to be unaffected by weathering and are thus often used to characterise variations in basalt and magma composition. When considered relative to chondritic abundances8, the overall REE distribution is a critical

  6. Rare earth elements in Holocene reefal microbialites: a new shallow seawater proxy

    Microsoft Academic Search

    Gregory E. Webb; Balz S. Kamber

    2000-01-01

    The concentration of rare earth elements and yttrium (REE + Y) was determined in Holocene Mg-calcite microbialites from shallow reef framework cavities at Heron Reef, Great Barrier Reef. Shale-normalized REE + Y patterns of 52 microbialite samples show: (1) uniform heavy REE enrichment (NdSN\\/YbSN = 0.236, SD = 0.026); (2) consistent negative Ce and positive La anomalies; (3) marine Y\\/Ho

  7. Rare earth elements in chloride-rich groundwater, Palo Duro Basin, Texas, USA

    Microsoft Academic Search

    D. C. Gosselin; M. R. Smith; E. A. Lepel; J. C. Laul

    1992-01-01

    Rare earth element (REE) data for groundwater samples from the Deep-Basin Brine aquifer of the Palo Duro Basin, Texas, USA, illustrates the potential use of REE for inferring groundwater flow paths through different geologic materials. The REE content of the groundwaters range over 2.5 orders of magnitude and are depleted by 10² to 10⁵ relative to aquifer materials. The shale-normalized

  8. The behaviour of the rare earth elements during mixing of river and sea waters

    Microsoft Academic Search

    J. Hoyle; H. Elderfield; A. Gledhill; M. Greaves

    1984-01-01

    Rare earth element concentrations have been measured in organic-rich Luce river water and coastal sea water. Concentrations ( e.g. ~350-1850 pmol\\/kg Nd in the Water of Luce and ~45-350 pmol\\/ kg Nd in Luce Bay) are related to the presence of particles, with 30-60% of the REE associated with >0.4-0.7 m particles, and to riverine Fe concentrations. REE fractionation occurs

  9. Evaluation of single extractants for assessing plant availability of rare earth elements in soils

    Microsoft Academic Search

    Fuliang Li; Xiaoquan Shan; Shuzhen Zhang

    2001-01-01

    The suitability of different extractants for estimating the plant availability of rare earth elements (REEs) in soils was assessed in a greenhouse study. 0.43 M CH3COOH, 0.01 M CaCl2, 0.1 M HCl, and DTPA were used as extractants and winter wheat (Triticum aestivum L.) as a test crop. Soil samples with diverse chemical and physical properties were collected from 9 different rural regions

  10. Pathway of rare-earth elements in a Brazilian forestry fragment

    Microsoft Academic Search

    Elvis J. França; Elisabete A. De Nadai Fernandes; Márcio A. Bacchi; Fábio S. Tagliaferro

    2002-01-01

    The Mata de Santa Genebra is a fragment of semi-deciduous tropical forest located in an urban area of São Paulo State, Brazil. Potential sources of rare-earth elements (REE), such as oil refinery, agricultural activities and high-traffic roads, are situated close to this region. In this study, the central portion of the fragment dominated by Pachystroma longifolium and Esenbeckia leiocarpa was

  11. Measurement of rare earths elements in Kakul phosphorite deposits of Pakistan using instrumental neutron activation analysis

    Microsoft Academic Search

    Sabiha-Javied; S. Waheed; N. Siddique; R. Shakoor; M. Tufail

    2010-01-01

    The rare earth elements (REEs) content of Kakul phosphate rock (PR) from different localities of the main Hazara deposits\\u000a of Pakistan were determined using instrumental neutron activation analysis (INAA). 25 phosphorite samples were collected from\\u000a different phosphorite sites and 6 samples representing different batches from the crushing plant near Kakul Mine. Concentrations\\u000a of seven REEs (Ce, Eu, La, Lu, Sm,

  12. Low-Molecular-Weight-Organic-Acids as Extractant to Predict Plant Bioavailability of Rare Earth Elements

    Microsoft Academic Search

    Shuzhen Zhang; Xiao-Quan Shan; Fuliang Li

    2000-01-01

    A mixture of malic acid and citric acid as extractant for the evaluation of plant bioavailability of rare earth elements (REEs) in soils is presented. Extractable REEs by malic-citric acid, acetic acid (CH3COOH), DTPA, EDTA, Mehlich 3 and total REEs in soils were compared with the REEs in winter wheat (Triticum aestivum L.) grown in the soils in greenhouse. Malic-citric

  13. Isolation and characterization of rare earth element-binding protein in roots of maize

    Microsoft Academic Search

    Dong-an Yuan; Xiao-quan Shan; Bei Wen; Qing Huai

    2001-01-01

    Rare earth element-binding protein was isolated from maize, which was grown under greenhouse conditions and characterized\\u000a in terms of molecular weight, amino acid composition, and ultraviolet absorption. The molecular weight of the maize protein\\u000a was determined to be 183,000, with two distinct subunits of approximately molecular weights of 22,000 and 69,000, respectively.\\u000a The protein is particularly rich in asparagine\\/aspartic acid,

  14. Determination of rare earth elements in bauxites by instrumental neutron activation analysis

    Microsoft Academic Search

    P. Vukoti?

    1983-01-01

    The instrumental neutron activation analysis method was used for determination of 12 rare earth elements in red and white\\u000a bauxites. Consideration was given to those systematic errors which in a relative method of analysis can result from the effects\\u000a of neutron self-shielding, photon self-absorption and fission interfering reactions, due to different chemical composition\\u000a of bauxite samples and the standard of

  15. Performance of lead iodide nuclear radiation detectors with the introduction of rare earth elements

    Microsoft Academic Search

    Mahmoud Hassan; Marie Matuchova; Karel Zdansky

    2006-01-01

    Lead iodide has been recognized as a promising material for room temperature radiation detectors. It has a wide band-gap (?\\u000a 2.3 eV), high atomic numbers (82, 53) and it is environmentally very stable compared to mercuric iodide. Electrical and optical\\u000a properties of lead iodide grown crystals purified under the influence of selected rare earth elements have been investigated.\\u000a Photo-luminescence and

  16. Rare earth element deposition in pelagic sediment at the Cenomanian-Turonian Boundary, Exmouth Plateau

    Microsoft Academic Search

    Gerald R. Dickens; Robert M. Owen

    1995-01-01

    Ocean Drilling Program (ODP) Site 762 (eastern Indian Ocean) includes a section of sediment that spans the Cenomanian-Turonian Boundary (CTB) and was deposited along a continental margin during a period of widespread oceanic O2 deficiency. The rare earth element (REE) content of pre- and post-boundary sediment is similar to that of present-day continental slope material deposited in well-oxygenated seawater, whereas

  17. Rare earth element deposition in pelagic sediment at the Cenomanian-Turonian Boundary, Exmouth Plateau

    Microsoft Academic Search

    Gerald R. Dickens; Robert M. Owen

    1995-01-01

    ODP Site 762 (eastern Indian Ocean) includes a section of sediment that spans the Cenomanian-Turonian Boundary (CTB) and was deposited along a continental margin during a period of widespread oceanic Oâ deficiency. The rare earth element (REE) content of pre- and post-boundary sediment is similar to that of present-day continental slope material deposited in well-oxygenated seawater, whereas the CTB section

  18. Rare earth element deposition in pelagic sediment at the Cenomanian-Turonian Boundary, Exmouth Plateau

    Microsoft Academic Search

    Gerald R. Dickens; Robert M. Owen

    1995-01-01

    ODP Site 762 (eastern Indian Ocean) includes a section of sediment that spans the Cenomanian-Turonian Boundary (CTB) and was deposited along a continental margin during a period of widespread oceanic O2 deficiency. The rare earth element (REE) content of pre- and post-boundary sediment is similar to that of present-day continental slope material deposited in well-oxygenated seawater, whereas the CTB section

  19. Role of ligands in accumulation and fractionation of rare earth elements in plants

    Microsoft Academic Search

    Shiming Ding; Tao Liang; Chaosheng Zhang; Juncai Yan; Zili Zhang; Qin Sun

    2005-01-01

    Few studies have been carried out on the effects of ligands on rare earth element (REE) bioaccumulation processes. In this\\u000a study, the effects of phosphate (Pi, an inorganic ligand) and citrate (an organic ligand) on accumulation and fractionation\\u000a of REEs in wheat were investigated using aqueous culture with extranous mixed REEs (MRE). The results show that initial Pi\\u000a solution culture

  20. [Determination of 15 trace rare earth elements in rice by microwave digestion ICP-MS].

    PubMed

    Liu, M; Liu, H; Wang, N; Wang, X

    1998-10-01

    An ICP-MS method for direct determination of 15 trace rare earth elements in rice was developed. Rapid and complete dissolution of rice was achieved by a microwave digestion procedure with concentrated nitric acid and hydrogen peroxide. The detection limits are 7.0-25.8 pg/mL, the recoveries for spiked samples are 95-105%, RSDs are 2.3-4.2%. This method is rapid, sensitive and accurate. PMID:15825372

  1. Fractionations of rare earth elements in plants and their conceptive model

    Microsoft Academic Search

    ShiMing Ding; Tao Liang; JunCai Yan; ZiLi Zhang; ZeChun Huang; YaNing Xie

    2007-01-01

    Fractionations of rare earth elements (REEs) and their mechanisms in soybean were studied through application of exogenous\\u000a mixed REEs under hydroponic conditions. Significant enrichment of middle REEs (MREEs) and heavy REEs (HREEs) was observed\\u000a in plant roots and leaves respectively, with slight fractionation between light REEs (LREEs) and HREEs in stems. Moreover,\\u000a the tetrad effect was observed in these organs.

  2. Geographical Characterization of Greek Olive Oils Using Rare Earth Elements Content and Supervised Chemometric Techniques

    Microsoft Academic Search

    Eleni G. Farmaki; Nikolaos S. Thomaidis; Katerina S. Minioti; Evaggelia Ioannou; Constantinos A. Georgiou; Constantinos E. Efstathiou

    2012-01-01

    Different ANNs models (Multi-layer Perceptrons (MLPs) and Radial Basis Function (RBF)) were developed and evaluated for the discrimination of olive oils produced in four Greek regions according to their geographical origin. For this purpose, ninety-seven samples were analyzed for 10 rare earth elements (REE) by ICP-MS. Moreover, two additional supervised techniques, discriminant analysis (DA) and classification trees (CTs), were applied

  3. Environmental biogeochemical behaviors of rare earth elements in soil–plant systems

    Microsoft Academic Search

    Tao Liang; Shen Zhang; Lijun Wang; Hsiang-Te Kung; Yuqi Wang; Aitang Hu; Shiming Ding

    2005-01-01

    With the continual increase in the utilization of rare earth elements (REEs) for industrial and agricultural purposes in China,\\u000a the research into the environmental biogeochemical behavior of REEs has become a pressing issue. The REEs’ content in soil\\u000a and various parts of wheat under different conditions in soil–plant systems were measured by INAA and ICP-MS. The results\\u000a showed four aspects.

  4. Laser-induced luminescence of rare-earth elements in natural zircon

    Microsoft Academic Search

    M Gaft; G Panczer; R Reisfeld; I Shinno

    2000-01-01

    Natural and synthetic zircons are investigated by time-resolved and high-resolution laser-induced luminescence to detect and ascribe various luminescence lines to a variety of rare-earth elements (REE). The selectivity of detection is possible by using different time delays after excitation, different gate widths and different excitation wavenumbers. This allowed us to detect REE in samples where they are hidden by intrinsic

  5. Light Rare Earth Elements enrichment in an acidic mine lake (Lusatia, Germany)

    Microsoft Academic Search

    Elke Bozau; Marc Leblanc; Jean Luc Seidel; Hans-Joachim Stärk

    2004-01-01

    The distribution of Rare Earth Elements (REE) was investigated in the acidic waters (lake and groundwater) of a lignite mining district (Germany). The Fe- and SO4-rich lake water (pH 2.7) displays high REE contents (e.g. La?70 ?g\\/l, Ce?160 ?g\\/l) and an enrichment of light REE (LREE) in the NASC normalised pattern. Considering the hydrodynamic model and geochemical data, the lake

  6. Complexation of trivalent rare earth elements (Ce, Eu, Gd, Tb, Yb) by carbonate ions

    Microsoft Academic Search

    Jong Hyeon Lee; R. H. Byrne

    1993-01-01

    Carbonate stability constants for five rare earth elements (Ce[sup 3+], Eu[sup 3+], Gd[sup 3+], Tb[sup 3+], and Yb[sup 3+]) have been determined at t = 25[degrees]C and 0.70 [plus minus] 0.02 M ionic strength through solvent exchange techniques. Estimated stability constants for Ce, Eu, and Yb are in close agreement with previous work. Analyses using Gd and Tb provide the

  7. Oceanic crustal thickness from seismic measurements and rare earth element inversions

    Microsoft Academic Search

    Robert S. White; Dan McKenzie; R. K. ONions

    1992-01-01

    Seismic refraction results show that the igneous section of oceanic crust averages 7.1 [plus minus] 0.8 km thick away from anomalous regions such as fracture zones and hot-spots, with extremal bounds of 5.0-8.5 km. Rare earth element inversions of the melt distribution in the mantle source region suggest that sufficient melt is generated under normal oceanic spreading centers to produce

  8. Ocean particle chemistry: The fractionation of rare earth elements between suspended particles and seawater

    Microsoft Academic Search

    E. R. Sholkovitz; W. M. Landing; B. L. Lewis

    1994-01-01

    Sargasso Sea suspended particles were sequentially digested with three chemical treatments (acetic acid, mild HCl\\/HNO[sub 3], and HF\\/HNO[sub 3]\\/HCl in a bomb). The latter two treatments dissolve detrital minerals, while the acetic acid removes surface coatings (organic matter and Mn oxides). The rare earth element (REE) composition of the surface coatings, in marked contrast to the crust-like REE composition of

  9. Methodologies for the analysis of rare earth elements and their relevance to reference materials

    Microsoft Academic Search

    B. Vijayalakshmy; T. Prasada Rao

    2001-01-01

    India has the third largest resources of rare earth elements (REE) in the world. These resources are essentially the monazite\\u000a sand present in the beaches of south-west, south-east, and mid-eastern coasts of India. Therefore, analytical methodologies\\u000a for the determination of REE in sea water and high-purity materials were developed. An overview of this work and its relevance\\u000a to the preparation

  10. Rare earth elements in forest-floor herbs as related to soil conditions and mineral nutrition

    Microsoft Academic Search

    Germund Tyler; Tommy Olsson

    2005-01-01

    Mixtures of rare earth elements (REEs) in fertilizers are widely used in Chinese agriculture to improve crop nutrition. REE\\u000a concentrations in wild-growing plants, especially herbs, are little known. This study describes differences in the concentrations\\u000a and proportions of REEs in eight forest-floor herbaceous plants and relates these differences to soil and mineral nutrient\\u000a conditions. REEs studied were yttrium (Y), lanthanum

  11. Metasomatic- hydrothermal processes in the Qatruyeh area, Iran: Mineralogy and trace elements geochemistry of metasedimentary rock- hosted iron indices

    NASA Astrophysics Data System (ADS)

    Rajabzadeh, M. A.; Asadi, S.

    2009-04-01

    The Qatruyeh iron indices are located at about 40 Km northeast of Neyriz, in the eastern edge of the HP-LT Sanandaj-Sirjan metamorphic belt, Zagros Mountain. Qatruyeh indices are contained within the metasedimentary rocks of the Late Proterozoic- early Paleozoic, which consists predominantly of dolomitic limestone, greenschist and quartzite. Field investigations, mineralogical studies and XRD analyses indicate that orebodies are dominated by magnetite. The structures of orebodies are mainly formed as thin layers and massive, which are located between dolomitic limestones and greenschists. Tourmaline, muscovite, chlorite, talc, martite, specularite, goethite, limonite, pyrite and chalcopyrite are present as minor minerals. The area has experienced two different stages of metasomatic- hydrothermal alterations. The iron ores were formed during the metasomatic- hydrothermal processes. Those processes are: (1) Na-Ca alteration and (2) mineralization (Oxidation-Sulfidation). The first stage of alteration follows the attainment of peak regional metamorphic condition (187± 2.6 Ma based on zircon SHRIMP U- Pb). This alteration is accompanied with Low-grade magnetite ores formation (50 % Fe2O3t), replacement textures, gradual transformation between layered ores and host rock. Wet chemistry analyses on magnetite shows that Na-Ca alteration caused increasing Cr and Cu as transition metals and Ni, Co and V were depleted. Metasedimentary rock-hosted iron deposits indicate that Na-Ca alteration increase Cu, Ni, Cr, Co, Zn as immobile elements and Na-Fe, whereas the LILE (Pb, Sr) were depleted. The formation of paragonite-tourmaline is also occurs as a part of iron deposition process in the stage. The second stage of metasomatic- hydrothermal alteration is accompanied with widespread veins and veinlets of High-grade magnetite (75 % Fe2O3t) - hematite- Quartz. Mineralization took place along host rock fractures with passage of saline, hot and oxidized aqueous fluids. Paragonite altered to muscovite in the host-rocks and ores in the stage. Sulfide replacement is generally occurred as a late stage phase.

  12. Thulium anomalies and rare earth element patterns in meteorites and Earth: Nebular fractionation and the nugget effect

    NASA Astrophysics Data System (ADS)

    Dauphas, Nicolas; Pourmand, Ali

    2015-08-01

    This study reports the bulk rare earth element (REEs, La-Lu) compositions of 41 chondrites, including 32 falls and 9 finds from carbonaceous (CI, CM, CO and CV), enstatite (EH and EL) and ordinary (H, L and LL) groups, as well as 2 enstatite achondrites (aubrite). The measurements were done in dynamic mode using multi-collector inductively coupled plasma mass spectrometers (MC-ICPMS), allowing precise quantification of mono-isotopic REEs (Pr, Tb, Ho and Tm). The CI-chondrite-normalized REE patterns (LaN/LuN; a proxy for fractionation of light vs. heavy REEs) and Eu anomalies in ordinary and enstatite chondrites show more scatter in more metamorphosed (petrologic types 4-6) than in unequilibrated (types 1-3) chondrites. This is due to parent-body redistribution of the REEs in various carrier phases during metamorphism. A model is presented that predicts the dispersion of elemental and isotopic ratios due to the nugget effect when the analyzed sample mass is limited and elements are concentrated in minor grains. The dispersion in REE patterns of equilibrated ordinary chondrites is reproduced well by this model, considering that REEs are concentrated in 200 ?m-size phosphates, which have high LaN/LuN ratios and negative Eu anomalies. Terrestrial rocks and samples from ordinary and enstatite chondrites display negative Tm anomalies of ?-4.5% relative to CI chondrites. In contrast, CM, CO and CV (except Allende) show no significant Tm anomalies. Allende CV chondrite shows large excess Tm (?+10%). These anomalies are similar to those found in group II refractory inclusions in meteorites but of much smaller magnitude. The presence of Tm anomalies in meteorites and terrestrial rocks suggests that either (i) the material in the inner part of the solar system was formed from a gas reservoir that had been depleted in refractory dust and carried positive Tm anomalies or (ii) CI chondrites are enriched in refractory dust and are not representative of solar composition for refractory elements. A new reference composition relevant to inner solar system bodies (CI?) is calculated by subtracting 0.15% of group II refractory inclusions to CI. The observed Tm anomalies in ordinary and enstatite chondrites and terrestrial rocks, relative to carbonaceous chondrites, indicate that material akin to carbonaceous chondrites must have represented a small fraction of the constituents of the Earth. Tm anomalies may be correlated with Ca isotopic fractionation in bulk planetary materials as they are both controlled by addition or removal of refractory material akin to fine-grained group II refractory inclusions.

  13. Siku: A Sea Ice Discrete Element Method Model on a Spherical Earth

    NASA Astrophysics Data System (ADS)

    Kulchitsky, A. V.; Hutchings, J. K.; Johnson, J.

    2014-12-01

    Offshore oil and gas exploration and production activities in the Beaufort and Chukchi Seas can be significantly and adversely affected by sea ice. In the event of an oil spill, sea ice complicates the tracking of ice/oil trajectories and can hinder cleanup operations. There is a need for a sea ice dynamics model that can accurately simulate ice pack deformation and failure to improve the ability to track ice/oil trajectories and support oil response operations. A discrete element method (DEM) model, where each ice floe is represented by discrete elements that are initially bonded (frozen) together will be used to address the difficulty continuum modeling approaches have with representing discrete phenomena in sea ice, such as the formation of leads and ridges. Each discrete element in the DEM is a rigid body driven by environmental forcing (wind, current and Coriolis forces) and interaction forces with other discrete elements (compression, shear, tension, bond rupture and regrowth). We introduce a new DEM model ``Siku'', currently under development, to simulate ice drift of an ice floe on a spherical Earth. We will present initial free-drift results. Siku is focused on improving sea ice interaction mechanics and providing an accurate geometrical representation needed for basin scale and regional simulations. Upon completion, Siku will be an open source GNU GPL licensed user friendly program with embedded python capability for setting up simulations "scenarios" and coupling with other models to provide forcing fields. We use a unique quaternion representation for position and orientation of polygon sea-ice elements that use a second order integration scheme of sea-ice element motion on the Earth's sphere that does not depend on the location of the element and, hence, avoids numerical problems near the pole.

  14. What Can Neutrinos Tell Us about Light Elements in Earth's Core?

    NASA Astrophysics Data System (ADS)

    Li, J.; Dye, S.; Enomoto, S.

    2014-12-01

    The light element composition of the Earth's core remains mysterious despite decades' of research. Without any direct samples, our knowledge of the core composition has relied on a diversity of constraints including the density and velocity profiles derived from seismic and geophysical observations, the composition models proposed on the basis of geochemical and cosmochemical measurements, the material properties determined by mineral physics investigations, and the thermal and dynamo requirements coming out of dynamic modeling. The leading candidates for the principal light element include hydrogen, carbon, oxygen, sulfur and silicon, in the order of increasing atomic number. While each candidate stands out in some aspects and raises questions in others, none has been universally accepted as the dominant light element in the core. The controversy arises partly because the properties and behavior of various iron-alloys at extreme pressure and temperature conditions have not been fully constrained. It is also conceivable that existing approaches will not produce unique solution, and therefore requires new strategies. Neutrino oscillation tomography has recently emerged as a promising technique to probe the composition of Earth's interior. Neutrinos are produced in the atmosphere by cosmic ray interactions. Atmospheric neutrinos pass through the Earth's mantle and core, with flavor oscillations being affected by the electron density of the medium along the trajectories. The unique sensitivity of the atmospheric neutrinos to electron density introduces a contrast between hydrogen, which has a higher electron density, and carbon, oxygen, sulfur, and silicon, which have lower and similar electron densities. With sufficient exposure to an appropriate energy range, atmospheric neutrino measurements may allow us to detect the presence of the core and measure its radius. Here we compare electron densities of candidate model compositions of Earth's core and estimate the exposure requirements for identifying the dominant light element thorough neutrino oscillation tomography for both neutrino mass hierarchies. In particular, we will evaluate if any of the on-going and next-generation projects IceCube, PINGU, MICA, and HyperK can tell us about the light elements in Earth's core.

  15. Determination of rare earth elements in environmental materials by inductively coupled plasma mass spectrometry

    SciTech Connect

    Panday, V.K.; Hoppstock, K.; Becker, J.S.; Dietze, H.J. [Zentralabteilung fuer Chemische Analysen, Juelich (Germany)

    1996-09-01

    Despite the fact that rare earth elements (REE) have found increasing use in modern technology only few data are available on their concentrations in biological and environmental samples. Inductively coupled plasma mass spectrometry (ICP-MS) has been employed to study the concentration of rare earth elements (REE) in various environmental materials (e.g., pine needles, mussel tissue, apple leaves) available from National Institute of Standards and Technology (NIST), the Bureau of European Communities (BCR), and the German Environmental Specimens Bank. After the decomposition of the environmental samples with HNO{sub 3}, the REE (present mostly in the ng/g-range) were separated from the matrix and simultaneously preconcentrated using liquid-liquid extraction with bis(2-ethyl hexyl)-ortho-phosphoric acid (HDEHP) in toluene as a selective reagent at pH = 2 and subsequent back extraction of the elements into the aqueous by 6M HNO{sub 3}. Recoveries of better 90% were obtained for almost all REE. A Perkin Elmer/Sciex ELAN 5000 ICP-MS and HR-ICP-MS ELEMENT from Finnigan MAT were used for quantitative analysis (by external calibration and ID-ICP-MS) of REE. The results of determination of REE concentrations agree well with the data available on some of these materials. Further supplement information on the contents of various REE in these materials.

  16. Geochemistry, petrofabrics and seismic properties of eclogites from the Chinese Continental Scientific Drilling boreholes in the Sulu UHP terrane, eastern China

    Microsoft Academic Search

    Qin Wang; Luigi Burlini; David Mainprice; Zhiqin Xu

    2009-01-01

    We present an integrated study of geochemistry, petrofabrics and seismic properties of strongly sheared eclogites from the Chinese Continental Scientific Drilling (CCSD) project in the Sulu ultrahigh-pressure (UHP) metamorphic terrane, eastern China. First, geochemical data characterize diverse protoliths of the studied eclogites. The positive Eu- and Sr-anomalies, negative Nb anomaly and flat portion of heavy rare earth elements in coarse-grained

  17. Geology, geochemistry and mineralogy of the lignite-hosted Ambassador palaeochannel uranium and multi-element deposit, Gunbarrel Basin, Western Australia

    NASA Astrophysics Data System (ADS)

    Douglas, Grant B.; Butt, Charles R. M.; Gray, David J.

    2011-10-01

    The Ambassador U and multi-element deposit occurs on the SW margin of the Gunbarrel Basin, Western Australia. Low-grade, flat-lying U mineralization averaging about 2 m thick at 0.03% U occurs in lignites at the redox front at the base of the weathering profile within a laterally extensive palaeochannel network. Uranium is principally associated with organic matter within the lignitic matrix, although rare discrete U minerals, such as coffinite and uraninite, are also present. The lignite is also enriched in a suite of other elements, principally base metals and sulphur, with concentrations of 0.3 ? 1% Cu, Pb, Ni, Co, Zn and total rare earth elements (REE) in some samples. Other element enrichments include: Cr, Cs, Sc, Se, Ta, Ti, Th, V and Zr as detrital heavy minerals of Zr, Ti and REE (oxides and silicates) or authigenic minerals of Cu, Bi, Pb, Zn, Ni, Se, Hg, Ti, Cr, Tl, V, U and REE (sulphides, vanadates, selenides, oxides, chlorides and native metals) and diffuse lignite impregnations. The Ambassador deposit probably formed from the convergence of redox-active weathering processes to unique source/host rocks, constrained within the palaeochannel. A proximal source of U and trace elements of lamproite/carbonatite origin is probable, as constrained by U-Pb isotope and U-Th disequilibria studies. Uranium and other metals were precipitated syngenetically with organic matter as it was deposited during a humid phase in the Late Eocene. Remobilization subsequently concentrated the metals in the upper 2 m of the lignite. This may have occurred during one or more periods of weathering and associated diagenesis, with the latest episode in the last 300,000 years.

  18. Bioleaching of rare earth and radioactive elements from red mud using Penicillium tricolor RM-10.

    PubMed

    Qu, Yang; Lian, Bin

    2013-05-01

    The aim of this work is to investigate biological leaching of rare earth elements (REEs) and radioactive elements from red mud, and to evaluate the radioactivity of the bioleached red mud used for construction materials. A filamentous, acid-producing fungi named RM-10, identified as Penicillium tricolor, is isolated from red mud. In our bioleaching experiments by using RM-10, a total concentration of 2% (w/v) red mud under one-step bioleaching process was generally found to give the maximum leaching ratios of the REEs and radioactive elements. However, the highest extraction yields are achieved under two-step bioleaching process at 10% (w/v) pulp density. At pulp densities of 2% and 5% (w/v), red mud processed under both one- and two-step bioleaching can meet the radioactivity regulations in China. PMID:23548400

  19. Complementary rare earth element patterns in unique achondrites, such as ALHA 77005 and shergottites, and in the earth

    NASA Technical Reports Server (NTRS)

    Ma, M.-S.; Schmitt, R. A.; Laul, J. C.

    1982-01-01

    Abundances of major, minor, and trace elements are determined in the Antarctic achondrite Allan Hills (ALHA) 77005 via sequential instrumental and radiochemical neutron activation analysis. The rare earth element (REE) abundances of ALHA 77005 reveal a unique chondritic normalized pattern; that is, the REEs are nearly unfractionated from La to Pr at approximately 1.0X chondrites, monotonically increased from Pr to Gd at approximately 3.4X with no Eu anomaly, nearly unfractionated from Gd and Ho and monotonically decreased from Ho to Lu at approximately 2.2X. It is noted that this unique REE pattern of ALHA 77005 can be modeled by a melting process involving a continuous melting and progressive partial removal of melt from a light REE enriched source material. In a model of this type, ALHA 77005 could represent either a crystallized cumulate from such a melt or the residual source material. Calculations show that the parent liquids for the shergottites could also be derived from a light REE enriched source material similar to that for ALHA 77005.

  20. Effect of rare earth elements on growth and nutrition of coconut palm and root competition for these elements between the palm and calotropis gigantea

    Microsoft Academic Search

    P. A. Wahid; M. S. Valiathan; N. V. Kamalam; J. T. Eapen; S. Vijayalakshmi; R. Krishna Prabhu; T. R. Mahalingam

    2000-01-01

    Absorption of rare earth elements (REEs) namely lanthanum (La), cerium (Ce), praseodymium (Pr), and neodymium (Nd) by coconut, competition between coconut and Calotropis gigantea L. for these elements in mixed culture and the effects of the REEs on growth and nutrition of the palm were studied in a pot culture. At a low rate of application, REEs promoted root growth

  1. Multi-element including rare earth content of lichens, bark, soils, and waste following industrial closure.

    PubMed

    Rusu, Ana-Maria; Chimonides, P D James; Jones, Gary C; Garcia-Sanchez, Raquel; Purvis, O William

    2006-08-01

    The fate of rare earth and other rare elements entering the environment is largely unknown. The lichen Hypogymnia physodes was transplanted over a 40 km long transect centered on a major metallurgical waste dump close to the Zlatna town center two weeks after smelter closure. Lichens, bark, soil, and waste dump materials were analyzed for 56 elements (including REE). Lichen and bark multi-element compositions were alike, reflecting fixation of elements of environmental concern and the ability for tree canopies to concentrate substances leading to enhanced deposition to both lichens and bark. Higher REE enrichment in lichens than in soil confirm efficient fixation in lichens. The negative europium anomaly in lichens and soil, similar to that in upper crust, confirm a strong crustal influence on lichen signatures across the transect area. Multi-element analysis supports the view that epiphytic lichens, unlike trees, are not influenced by lower groundwater, and they are excellent indicators for REE and other rare elements entering the surface environment, difficult to detect by conventional means. PMID:16913112

  2. New Rare Earth Element Abundance Distributions for the Sun and Five r-Process-Rich Very Metal-Poor Stars

    E-print Network

    Sneden, Christopher; Cowan, John J; Ivans, Inese I; Hartog, Elizabeth A Den

    2009-01-01

    We have derived new abundances of the rare-earth elements Pr, Dy, Tm, Yb, and Lu for the solar photosphere and for five very metal-poor, neutron-capture r-process-rich giant stars. The photospheric values for all five elements are in good agreement with meteoritic abundances. For the low metallicity sample, these abundances have been combined with new Ce abundances from a companion paper, and reconsideration of a few other elements in individual stars, to produce internally-consistent Ba, rare-earth, and Hf (56<= Z <= 72) element distributions. These have been used in a critical comparison between stellar and solar r-process abundance mixes.

  3. Multielement and rare earth element composition of lichens, mosses, and vascular plants from the Central Barrenlands, Nunavut, Canada

    Microsoft Academic Search

    J. Chiarenzelli; L. Aspler; C. Dunn; B. Cousens; D. Ozarko; K. Powis

    2001-01-01

    Lichen (n=12) and moss (n=6) species from a remote region of northern Canada have remarkably similar multi-element patterns suggesting they are non-specific accumulators of metals under existing conditions. Within individual species the concentration of many metals analyzed range over an order of magnitude. Many elements have a positive correlation with multi-element (n=48) and REE (rare earth element) totals. Others, such

  4. Rare earth elements recycling from waste phosphor by dual hydrochloric acid dissolution.

    PubMed

    Liu, Hu; Zhang, Shengen; Pan, Dean; Tian, Jianjun; Yang, Min; Wu, Maolin; Volinsky, Alex A

    2014-05-15

    This paper is a comparative study of recycling rare earth elements from waste phosphor, which focuses on the leaching rate and the technical principle. The traditional and dual dissolution by hydrochloric acid (DHA) methods were compared. The method of dual dissolution by hydrochloric acid has been developed. The Red rare earth phosphor (Y0.95Eu0.05)2O3 in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce0.67Tb0.33MgAl11O19) and the Blue phosphor (Ba0.9Eu0.1MgAl10O17) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO2 are removed by washing. The insoluble matter is leached by the hydrochloric acid, followed by solvent extraction and precipitation (the DHA method). In comparison, the total leaching rate of the rare earth elements was 94.6% by DHA, which is much higher than 42.08% achieved by the traditional method. The leaching rate of Y, Eu, Ce and Tb reached 94.6%, 99.05%, 71.45%, and 76.22%, respectively. DHA can decrease the consumption of chemicals and energy. The suggested DHA method is feasible for industrial applications. PMID:24681591

  5. Effect of rare earth elements from monazite on growth-vigor and chemical composition of Phaseolus vulgaris

    Microsoft Academic Search

    H. H. Sharoubeem; N. E. Milad

    1966-01-01

    This investigation deals with the effect of different concentrations of rare earth elements (as monazite extract containing Th, Ce, La, Pr, and Nd in the form of nitrates) on the growth and nutritional status of Phaseolus vulgaris. Phaseolus vulgaris plants were grown in sand cultures to which rare earths were added to supply 2.5, 5, 7.5, and 10 ppm. Growth

  6. Comparison of speciation and bioavailability of rare earth elements between wet rhizosphere soil and air-dried bulk soil

    Microsoft Academic Search

    Zhongwen Wang; Xiao-quan Shan; Shuzhen Zhang

    2001-01-01

    A comparison was made between the speciation and bioavailability of rare earth elements in rhizosphere and nonrhizosphere soils and between wet and air-dried soils under greenhouse conditions by using a homemade rhizobox. The speciation of rare earth elements in soils is experimentally defined as water soluble, exchangeable and carbonate bound (B1), Fe–Mn oxide bound (B2) and organic matter and sulfide

  7. Photosystem 2 activities of hyper-accumulator Dicranopteris dichotoma Bernh from a light rare earth elements mine

    Microsoft Academic Search

    L. F. Wang; H. B. Ji; K. Z. Bai; L. B. Li; T. Y. Kuang

    2006-01-01

    The distribution of rare earth elements (REEs) in the fern Dicranopteris dichotoma Bernh plants from a light rare earth elements mine (LRM) and a non-mining (NM) area in Longnan county of Jiangxi province,\\u000a China were investigated by means of inductively coupled plasma-mass spectrometry, transmission electron microscopy, and energy-dispersive\\u000a X-ray microanalysis. The photosynthetic characteristics of D. dichotoma were studied by chlorophyll

  8. Determination of Trace Rare Earth Elements in Plant and Soil Samples by Inductively Coupled Plasma-Mass Spectrometry

    Microsoft Academic Search

    Xinde Cao; Ying Chen; Zhimang Gu; Xiaorong Wang

    2000-01-01

    Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) was employed to determine the concentration of rare earth elements (REEs) in plants and soils. Sample preparation and analytical conditions were investigated to set up a simple routine procedure for measuring rare earth elements. For prompt sample decomposition, a microwave digestion technique was successfully used with an acid mixture of HCl+HNO3+HF. Detection limits, reproducibility, accuracy

  9. Analytical long-term orbit predictions with the combined effect of Earth's flattening and atmospheric oblateness using KS element equations

    Microsoft Academic Search

    Lila Sivan Kutty Nair

    2008-01-01

    An analytical theory for long-term orbit motion of near-Earth satellite orbits with Earth's zonal harmonic J2 and air drag is developed in terms of KS elements, utilizing an analytical oblate exponential atmospheric density model. Due to symmetry in KS element equations, only one of the eight equations is integrated analytically to obtain the state vector at the end of each

  10. Monopole elements with disk ground planes on flat earth: Atlas of directivity, radiation efficiency, radiation resistance, and input impedance

    Microsoft Academic Search

    M. M. Weiner

    1992-01-01

    Richmond's moment-method programs RICHMOND3 and RICHMOND4 for monopole elements with disk ground planes above flat Earth are used to obtain computer plots of directivity, radiation efficiency, radiation resistance, and input impedance at 15 MHz. Results, in the form of an atlas, are presented as a function of Earth classification for thin, quarter-wave monopole elements whose ground planes or radii 0

  11. Concentration levels of rare-earth elements and thorium in plants from the Morro do Ferro environment as an indicator for the biological availability of transuranium elements

    Microsoft Academic Search

    N. Miekeley; E. A. Casartelli; R. M. Dotto

    1994-01-01

    Plants and soils from a natural thorium and rare-earth element occurrence (Morro do Ferro, Brazil) were analyzed by alpha spectrometry (Th) and ICP-AES (REE), after pre-concentration of the elements by solvent extraction, co-precipitation and ion exchange procedures. Leaching experiments with humic acid solutions and different soils were performed to estimate the fraction of elements biologically available. High concentrations of the

  12. The chemistry of the light rare-earth elements as determined by electron energy loss spectroscopy

    SciTech Connect

    Fortner, J.A.; Buck, E.C. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439 (United States)] [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439 (United States)

    1996-06-01

    The energy loss spectra of the rare earths are characterized by sharp {ital M}{sub 4,5} edges, the relative intensities of which are characteristic of the 4{ital f}-shell occupancy of the excited ion. For the light rare earths, the dependence of these relative peak heights on 4{ital f}-shell occupancy is quite pronounced. Thus they may be used to determine the oxidation state of the multivalent elements Ce and Pr. The second derivative of the spectrum is shown to be extremely sensitive to the chemical environment. Modern instrumentation and detection techniques allow the oxidation state of Ce and Pr to be determined even when they are present as only minor constituents. {copyright} {ital 1996 American Institute of Physics.}

  13. Biological availability and environmental behaviour of Rare Earth Elements in soils of Hesse, Central Germany

    NASA Astrophysics Data System (ADS)

    Loell, M.; Duering, R.-A.; Felix-Henningsen, P.

    2009-04-01

    Rare earth elements (REEs) comprise a group of 17 transition metals with very similar chemical and physical properties. They include the elements scandium (Sc), yttrium (Y) and lanthanum (La) and the 14 elements (cerium to lutetium) that follow La in the periodic table. Their average abundance in the earth's crust varies from 0,01 to 0,02% so they are as common as Cu and Pb. Beside their widespread use in industry, REEs are applied in Chinese agriculture. Their beneficial effects both on crop yield and on animal production are reported in various investigations. As a result - by using microelement fertilisers and manure - REEs enter the pedosphere while their fate and behaviour in the environment up to now remains unexamined. The first aim of our investigation was to evaluate the concentration of REEs in agricultural used soils in central Germany (Hesse) by ICP-MS. In addition to their total concentration (aqua regia digestion) their bioavailable contents - determined by EDTA (potentially available fraction) and ammonium nitrate extraction (mobile fraction) - were analysed. The occurrence of the three REE fractions in different soils will be discussed and influencing soil properties (e.g. pH-value, content of clay and organic carbon) will be revealed. Additionally the uptake of REEs by grassland plants was determined and resulting transfer factors will be presented.

  14. Determination of rare earth elements in tomato plants by inductively coupled plasma mass spectrometry techniques.

    PubMed

    Spalla, S; Baffi, C; Barbante, C; Turetta, C; Turretta, C; Cozzi, G; Beone, G M; Bettinelli, M

    2009-10-30

    In recent years identification of the geographical origin of food has grown more important as consumers have become interested in knowing the provenance of the food that they purchase and eat. Certification schemes and labels have thus been developed to protect consumers and genuine producers from the improper use of popular brand names or renowned geographical origins. As the tomato is one of the major components of what is considered to be the healthy Mediterranean diet, it is important to be able to determine the geographical origin of tomatoes and tomato-based products such as tomato sauce. The aim of this work is to develop an analytical method to determine rare earth elements (RRE) for the control of the geographic origin of tomatoes. The content of REE in tomato plant samples collected from an agricultural area in Piacenza, Italy, was determined, using four different digestion procedures with and without HF. Microwave dissolution with HNO3 + H2O2 proved to be the most suitable digestion procedure. Inductively coupled plasma quadrupole mass spectrometry (ICPQMS) and inductively coupled plasma sector field plasma mass spectrometry (ICPSFMS) instruments, both coupled with a desolvation system, were used to determine the REE in tomato plants in two different laboratories. A matched calibration curve method was used for the quantification of the analytes. The detection limits (MDLs) of the method ranged from 0.03 ng g(-1) for Ho, Tm, and Lu to 2 ng g(-1) for La and Ce. The precision, in terms of relative standard deviation on six replicates, was good, with values ranging, on average, from 6.0% for LREE (light rare earth elements) to 16.5% for HREE (heavy rare earth elements). These detection limits allowed the determination of the very low concentrations of REE present in tomato berries. For the concentrations of REE in tomato plants, the following trend was observed: roots > leaves > stems > berries. PMID:19757452

  15. TES microcalorimeter SEM-EDS system for rare-earth elements analyses

    NASA Astrophysics Data System (ADS)

    Uehara, Seiichiro; Takai, Yasuhiro; Shirose, Yohei; Fujii, Yuki

    A field-emission scanning electron microscope (FE-SEM) with energy-dispersive X-ray spectrometer (EDS) detector of a superconducting transition-edge sensor (TES) microcalorimeter is a new system for electron-microprobe chemical analyses. FE-SEM with TES was used for qualitative and semi-quantitative analyses of rare-earth elements (REE) at a low accelerating voltage of 5 kV. Four characteristic M-lines were detected in the LaB6 spectrum: LaM? at 640, LaM?? at 841, LaM? at 1021, and a weak line (M2N4 transition) at 1100 eV. The spectra of other rare-earth borides, rare-earth phosphates, and monazite were assigned in the same way as the La M-lines were. For quantitative analyses, we used a calibration curve method, using standard specimens of known chemical compositions. Linear calibration curves for plots of P, Ca, La, Ce, Pr, and Nd intensities versus each weight percentage were obtained. Semi-quantitative analyses of rare-earth minerals should be carried out at low accelerating voltages using a calibration curve method. In a TES-EDS system, a low accelerating voltage can be used to improve the spatial resolution, without the sensitivity disadvantages of low-energy X-ray emissions. Moreover, a strong increase in the M?? intensity with increasing atomic number Z was seen, so the detection limits of heavy REE was much lower than those of light REEs. These results suggest that the TES-EDS system could be a useful analytical tool in rare-earth mineralogy.

  16. TOPICAL REVIEW: Melt-processed light rare earth element - Ba - Cu - O

    Microsoft Academic Search

    M. Murakami; N. Sakai; T. Higuchi; S. I. Yoo

    1996-01-01

    Unlike Y123 which forms only a stoichiometric compound, the light rare earth elements (LREs: La, Nd, Sm, Eu, Gd) form a solid solution 0953-2048\\/9\\/12\\/001\\/img1. The presence of such solid solution caused a depression in the superconducting transition temperatures 0953-2048\\/9\\/12\\/001\\/img2, particularly for La123, Nd123 and Sm123 when they are melt processed in air. Recently, we have found that the 0953-2048\\/9\\/12\\/001\\/img3 of

  17. Microwave absorbing properties of rare-earth elements substituted W-type barium ferrite

    Microsoft Academic Search

    Wang Jing; Zhang Hong; Bai Shuxin; Chen Ke; Zhang Changrui

    2007-01-01

    W-type barium ferrites Ba(MnZn)0.3Co1.4R0.01Fe15.99O27 with R=Dy, Nd and Pr were prepared by chemical coprecipitation method. Effects of rare-earth elements (RE) substitution on microstructural and electromagnetic properties were analyzed. The results show that a small amount of RE3+ ions can replace Fe3+ ions and adjust hyperfine parameters. An obvious increase in natural resonance frequency and high frequency relaxation, and a sharp

  18. Phase composition of ceramics in systems with oxides of rare-earth elements, manganese, and titanium

    Microsoft Academic Search

    S. V. Stefanovskii; S. V. Yudintsev; B. S. Nikonov; O. I. Stefanovskaya

    2007-01-01

    Ceramics based on systems with oxides of rare-earth elements (REE: Y2O3, Sm2O3, Gd2O3), manganese, and titanium, considered as hosts for immobilization of REE- and actinide-containing radioactive wastes (RAW),\\u000a were prepared by cold pressing and sintering at 1300–1400?C, and also by plasma treatment. Phases of the pyrochlore-murataite\\u000a series are prevalent in the ceramics, and perovskite-pyrophanite-type phases are impurity phases, as well

  19. Analysis of rare earth elements in silicates by ion microprobe using doubly-charged ions

    SciTech Connect

    Riciputi, L.R.; Christie, W.H.; Cole, D.R.; Rosseel, T.M. (Oak Ridge National Lab., TN (United States))

    1993-05-01

    A technique for measurement of rare earth element (REE) concentrations in silicates using a Camecaims-4f ion microprobe and doubly-charged, odd-mass isotopes has been developed. The secondary ion spectra of the doubly-charged odd-mass REE are virtually free of interferences, allowing measurements to be carried out at low energies and without the need for spectral stripping. Calibration lines have been established for La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, Tm, and Yb using a suite of clinopyroxene standards. This technique offers a relatively fast, simple approach for the in-situ analysis of REE on spots of <20 [mu]m and detection limits of <15 ppb for most elements. 17 refs., 2 figs., 5 tabs.

  20. 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. PMID:21838699

  1. Revisiting the plant hyperaccumulation criteria to rare plants and earth abundant elements.

    PubMed

    Branquinho, Cristina; Serrano, Helena Cristina; Pinto, Manuel João; Martins-Loução, Maria Amélia

    2007-03-01

    The several established criteria to define a hyperaccumulator plant were applied to a rare and endangered species, Plantago almogravensis, and to the 3rd most abundant element in the earth crust, Al. Using the most common criteria, P. almogravensis undoubtedly is an Al hyperaccumulator plant. If the recent proposed requirements were considered, most of them matching those for a plant to be used in phytoextraction, it can only be considered an unusual accumulator of Al. A discussion is made concerning the several criteria of a hyperaccumulator plant in order to include rare and endemic ones and abundant elements. In ecological terms, the enrichment in Al and Fe observed may account for the differences in the vegetation pattern. Due to the rarity and endangered nature of this plant, the contribution of this work is also relevant for the ecological understanding and the development of conservation options of this endemic species. PMID:17046127

  2. Biosorption of Uranium and Rare Earth Elements Using Biomass of Algae

    PubMed Central

    Sakamoto, Nobuo; Kano, Naoki; Imaizumi, Hiroshi

    2008-01-01

    In order to investigate the behavior of rare earth elements (REEs) and uranium (U) in marine organism, the concentrations of REEs and U in some brown algae samples taken on the coast of Niigata Prefecture were determined. In addition, laboratory model experiment to uptake these elements using living and dried algae (Undaria pinnatifida and Sargassum hemiphyllum) was also carried out to survey the uptake and bioaccumulation mechanism of REEs and U in algae. Consequently, the following matters have been mainly clarified. (1) The order of the concentration of REEs for each organ in Sargassum hemiphyllum is “main branch” > “leaf” > “vesicle,” however for U, the order is “leaf” > “vesicle” > “main branch.” (2) The concentration of REEs in Sargassum hemiphyllum may be strongly affected by suspended solid in seawater. (3) The uptake and/or accumulate mechanism of REEs in brown algae may be different from that of U. PMID:19081786

  3. Application of rare-earth element Y in refining impure copper

    NASA Astrophysics Data System (ADS)

    Li, Hai-hong; Sun, Xue-qin; Zhang, Shang-zhou; Zhao, Qin-yi; Wang, Guang-zhen

    2015-05-01

    The effects of rare-earth element Y in refining impure copper were investigated in this paper. The composition, microstructures, and corrosion resistance properties of impure copper before and after refinement with Y were investigated using direct-reading spectrometry, inductively coupled plasma atomic emission spectrometry, optical microscopy, scanning electron microscopy, and potentiodynamic polarization measurements. The results show that the concentrations of impurities S, As, Sb, Bi, Al, Cd, and Se are remarkably decreased. Adding an appropriate amount of Y refines the microstructure and enhances the corrosion resistance properties of impure copper in HCl solution via a purification effect. The formation enthalpies of compounds formed between Y and various impurity elements were calculated on the basis of Miedema's theory. The thermodynamic mechanisms of the refinement of impure copper by Y were also discussed

  4. Rare earth elements in stream waters from the Rokko granite area, Japan: Effect of weathering degree of watershed rocks

    Microsoft Academic Search

    TAIGA NAKAJIMA; YASUTAKA TERAKADO

    The concentrations of major elements and rare earth elements (REE) of the stream waters from the Rokko granite area, Japan, were analyzed to examine the relationship between the degree of weathering and chemistry of the waters. The clay minerals in the related soils from the watershed areas were also examined. It was found that the relative proportion of kaolinite to

  5. Sample Preparation for Determination of Rare Earth Elements in Geological Samples by ICP-MS: A Critical Review

    Microsoft Academic Search

    Frederico Garcia Pinto; Rainério Escalfoni Junior; Tatiana Dillenburg SaintPierre

    2012-01-01

    The presence of rare earth elements (REE) in geological materials provides important information about the formation and the geochemical processes suffered by the rocks. Therefore, there is a constant necessity for accurate data and reliable and fast analytical methods. However, the low concentrations of these elements typically found in rocks require quantification by sufficiently sensitive techniques, such as Inductively Coupled

  6. Behavior of rare earth and trace elements in Lake Tanganyika and its three major tributaries

    NASA Astrophysics Data System (ADS)

    Sako, A.; Johnson, R.

    2004-12-01

    Water samples were collected, during the rainy and dry seasons 2003, from three major rivers and several locations of the Lake Tanganyika. They were directly filtered (0.45 im pore size) into pre-washed polyethylene bottles, and acidified at pH 2. Finnigan Element 2 high resolution (HR)-IC-MPS was used to measure trace and rare earth elements (REE) concentrations under clean laboratory conditions, and (115In) was used as an internal standard. Because of the close relationship between light rare earth element (LREE) and Fe, riverine REE of the three were used to study the process trace element scavenging by Fe oxyhydroxides in three different two sub-basins of the lake. This confirmed by the significant positive correlation between Nd and Fe. The vertical distribution of Fe and Mn oxides were also used to investigate removal and release of trace elements in the water column. The normalized lacustrine REE to their riverine counterpart showed a gradual removal of REE across the lake, which was in the order of LREE>MREE>HREE. Hence, the rivers are the sole source of the lacustrine REE abundance. Coincidence of Fe maxima with those of Ce anomalies and La indicates that trace element profiles are chiefly controlled by the coating of Fe oxyhydroxides through oxidation of Fe2+ to Fe3+ under high dissolved oxygen contents and pH and vice versa. Due to differences in hydrodynamics between the extreme ends of the lake (upwelling in the southern end during the dry season), high mixing between bottom water and surface was observed at the surface in the Southern Basin while the mixing occurred mainly between 40 m and 80 m depth in the Northern Basin. There was also a clear similarity between Ba and NO3- and PO43- profiles in the southern end of the lake, supporting the idea that deep anoxic water, rich in nutrients and trace elements, are bought the surface during this period of intensive upwelling. In conclusion, the surface water chemical compositions of Lake Tanganyika are controlled by fluvial inputs and the seasonal changes in hydrodynamics across the lake.

  7. Spatial and temporal dynamics of sediment in contrasted mountainous watersheds (Mexican transvolcanic belt and French Southern Alps) combining river gauging, elemental geochemistry and fallout radionuclides

    NASA Astrophysics Data System (ADS)

    Evrard, O.; Navratil, O.; Gratiot, N.; Némery, J.; Duvert, C.; Ayrault, S.; Lefèvre, I.; Legout, C.; Bonté, P.; Esteves, M.

    2009-12-01

    In mountainous environments, an excessive fine sediment supply to the rivers typically leads to an increase in water turbidity, contaminant transport and a rapid filling of reservoirs. This situation is particularly problematic in regions where water reservoirs are used to provide drinking water to large cities (e.g. in central Mexico) or where stream water is used to run hydroelectric power plants (e.g. in the French Southern Alps). In such areas, sediment source areas first need to be delineated and sediment fluxes between hillslopes and the river system must be better understood before implementing efficient erosion control measures. In this context, the STREAMS (« Sediment Transport and Erosion Across MountainS ») project funded by the French National Research Agency (ANR) aims at understanding the spatial and temporal dynamics of sediment at the scale of mountainous watersheds (between 500 - 1000 km2) located in contrasted environments. This 3-years study is carried out simultaneously in a volcanic watershed located in the Mexican transvolcanic belt undergoing a subhumid tropical climate, as well as in a sedimentary watershed of the French Southern Alps undergoing a transitional climate with Mediterranean and continental influences. One of the main specificities of this project consists in combining traditional monitoring techniques (i.e. installation of river gauges, turbidimeters and sediment samplers in several sub-catchments) and sediment fingerprinting using elemental geochemistry (measured by Instrumental Neutron Activation Analysis - INAA - and Inductively Coupled Plasma - Mass Spectrometry - ICP-MS) and fallout radionuclides (measured by gamma spectrometry). In the French watershed, geochemical analysis allows outlining different sediment sources (e.g. the contribution of calcareous vs. marl-covered sub-watersheds). Radionuclide ratios (e.g.Be-7/Cs-137) allow identifying the dominant erosion processes occurring within the watershed. Areas mostly affected by gully erosion, rill or sheet erosion have been delineated. Furthermore, the measurement of radionuclide content in suspended sediment after the snowmelt suggests that most of this sediment consists in resuspended material rather than on newly eroded soil. In the Mexican watershed, a different contribution of andisols and acrisols to erosion is suspected. Overall, the bulk of erosion is generated by rather small areas within the watershed. In this region characterised by a succession of wet and dry seasons, the Be-7 content in rainfall and sediment has been measured at the scale of a 2.5 km2 sub-watershed in order to better understand the erosion transfer between hillslopes and rivers during the rainy season. This outlines the contribution of individual storms to seasonal erosion. Overall, this study brings important insights about sediment sources and fluxes within these watersheds located in contrasted environments. A further step consists in comparing experimental results with model outputs, and to evaluate the impact of on-going erosion mitigation measures.

  8. Thermodynamic properties of the rare earth element vapor complexes LnAl{sub 3}Cl{sub 12} from Ln = La to Ln = Lu

    SciTech Connect

    Zhi-Chang Wang; Lin-Shan Wang [Northeastern Univ., Liaoning (China)

    1997-04-09

    The rare earth element complexes have never been analyzed in the gaseous state due to experimental concerns. The thermodynamic properties of rare earth element complexes are important for various applications, from high-intensity discharge lamps to recovery of rare earth metals. 46 refs., 4 figs., 1 tab.

  9. The light element component of the Earth’s core: Constraints from in situ X-Radiography in the LHDAC

    NASA Astrophysics Data System (ADS)

    Lord, O. T.; Walter, M. J.; Walker, D.; Clark, S. M.

    2009-12-01

    The light element budget of the Earth’s core depends in part on the high-pressure melting relations of the relevant iron rich binary systems. Candidate alloying elements include H, C, O, Si and S, due to their cosmochemical abundance. Many of these systems are known to contain eutectic points, the temperatures and compositions of which are critical to reconstructing the phase relations of these systems. Thus far most studies reporting the composition of eutectic liquids depend on ex situ analysis with a potential for systematic errors introduced by quench induced exsolution. To circumvent this issue we have developed an in situ technique for the determination of liquid compositions in iron-rich binary systems at simultaneous high-pressure and high-temperature conditions. Samples consist of Fe(1-x)O or FeS, surrounded by a ring of iron forming a ‘donut’ with a diameter of ~100?m and a thickness of ~20?m. Pressure is monitored by ruby fluorescence. The sample is heated at the boundary between the iron and light element compound using two 100 W IR lasers in a double-sided configuration at beamline 12.2.2 at the Advanced Light Source. Temperature is measured by spectroradiometry. Before, during and after melting, X-radiographic images of the sample are taken by shining a defocused beam of synchrotron X-rays through the sample and onto a CdWO4 phosphor. The visible light from the phosphor is then focused onto a high resolution CCD, where absorption contrast images are recorded. The absorption of the molten region is then determined, and it’s composition calculated by comparison to the absorption of the two solid end members. In previous work we measured the composition of the Fe-FeS eutectic to 20 GPa and the Fe-Fe3C eutectic to 44 GPa [1,2]. Further, we saw no discernible solubility of oxygen in liquid iron up to 43 GPa [1]. Here we extend the data for sulfur up to 70 GPa and for oxygen up to 63 GPa. Our new sulfur data fit well with previous studies at lower pressure, and suggest that the sulfur content of the eutectic is tending to ~15wt% with increasing pressure. In the Fe-FeO system, upon reaching the Fe-FeO eutectic temperature (indicated by a plateau in the power-temperature function), no evidence of a melt was seen within the absorption contrast images. Only when the temperature was raised above this first plateau to a second plateau, representing the melting point of FeO did a ‘ledge’ appear in the absorption contrast image, suggesting the presence of a liquid with a composition intermediate between Fe and FeO. Further, the composition of this ledge was pressure insensitive, and close to a 50:50 mix of Fe and FeO. We interpret these results as the formation of a eutectic melt with an oxygen content below the detection limit (~1 wt%), followed by melting of the FeO end-member and the subsequent mixing of the two liquid phases. These results suggest that the solubility of oxygen remains below ~1wt% beyond 60 GPa, in contradiction with several recent studies [3]. [1] Walker, D., et al. Chem Geol., 2008. [2] Lord, O. T., et al. EPSL, 2009. [3] Seagle, C. T., et al. EPSL, 2008.

  10. The geochemistry of iodine — a review

    Microsoft Academic Search

    Ronald Fuge; Christopher C. Johnson

    1986-01-01

    Iodine has long been recognised as an important element environmentally. Despite this there are many gaps in our knowledge of its geochemistry and even where information is available much of this is based on old data which, in the light of recent data, are suspect.Iodine forms few independent minerals and is unlikely to enter most rock-forming minerals. In igneous rocks

  11. 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 ?m (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)). PMID:24657942

  12. While China's dominance in rare earths dips, concerns remain about these and other elements

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2012-05-01

    China's dominance in the production of rare earth elements (REEs) peaked with that nation producing 97% of them in 2010; this number already has dipped to 90% in 2012 as mines in other nations are coming online, according to REE expert Karl Gschneidner Jr., a professor at Iowa State University's Ames Laboratory. Chinese production could drop to 60% by 2014, with production increasing at mines in the United States and other countries, he said. However, this reduction in China's share of REE production does not signal an end to the production crisis in REEs and other critical minerals, Gschneidner and others noted during a 1 May panel discussion on critical materials shortages at the AGU Science Policy Conference in Washington, D. C. REEs are a group of 17 chemically similar metallic elements used in a variety of electronic, optical, magnetic, and catalytic applications, and despite their name, they are relatively plentiful in the Earth's crust. China's control of known REE reserves has dropped from 75% in 1975 to 30.9% in 2012, with other regions also having large reserves, including the Commonwealth of Independent States (some former Soviet Republic states), the United States, and Australia, according to Gschneidner. Critical minerals are mineral commodities that are particularly important for a nation's economy or national defense that could potentially face supply disruptions.

  13. Recovery of rare earth elements from the sulfothermophilic red alga Galdieria sulphuraria using aqueous acid.

    PubMed

    Minoda, Ayumi; Sawada, Hitomi; Suzuki, Sonoe; Miyashita, Shin-ichi; Inagaki, Kazumi; Yamamoto, Takaiku; Tsuzuki, Mikio

    2015-02-01

    The demand for rare earth elements has increased dramatically in recent years because of their numerous industrial applications, and considerable research efforts have consequently been directed toward recycling these materials. The accumulation of metals in microorganisms is a low-cost and environmentally friendly method for the recovery of metals present in the environment at low levels. Numerous metals, including rare earth elements, can be readily dissolved in aqueous acid, but the efficiency of metal biosorption is usually decreased under the acidic conditions. In this report, we have investigated the use of the sulfothermophilic red alga Galdieria sulphuraria for the recovery of metals, with particular emphasis on the recovery of rare earth metals. Of the five different growth conditions investigated where G. sulphuraria could undergo an adaptation process, Nd(III), Dy(III), and Cu(II) were efficiently recovered from a solution containing a mixture of different metals under semi-anaerobic heterotrophic condition at a pH of 2.5. G. sulphuraria also recovered Nd(III), Dy(III), La(III), and Cu(II) with greater than 90% efficiency at a concentration of 0.5 ppm. The efficiency remained unchanged at pH values in the range of 1.5-2.5. Furthermore, at pH values in the range of 1.0-1.5, the lanthanoid ions were collected much more efficiently into the cell fractions than Cu(II) and therefore successfully separated from the Cu(II) dissolved in the aqueous acid. Microscope observation of the cells using alizarin red suggested that the metals were accumulating inside of the cells. Experiments using dead cells suggested that this phenomenon was a biological process involving specific activities within the cells. PMID:25283836

  14. Computational Design of Solar Energy Harvesting Materials Made of Earth-Abundant Elements

    NASA Astrophysics Data System (ADS)

    Sun, Yiyang

    2012-02-01

    Very large-scale deployment of photovoltaic (PV) technology based on both the first and second generation solar cells posts serious questions on the materials supply as they rely on either high-purity and high-quality silicon crystals or rare elements such as indium and tellurium. ``Ancient'' PV materials made of earth-abundant elements, such as oxides and sulfides of copper and iron, have attracted resurgent interests. There is also intensive research devoted to the search for ``modern'' earth-abundant PV materials, with a recent promising example being Cu2ZnSnSe4. Computational approaches play a key role in this endeavor by guiding the screening and optimization of the materials toward high device performance. In this paper, I will focus on two aspects of computational design of earth-abundant PV materials. First, I will discuss the methods for accurately predicting band gaps of semiconductor materials. The emphasis will be on the performance of hybrid functional method on different classes of materials. Based on these understandings, I will discuss how to tune the band gap of a material to match the solar spectrum. For example, one could reduce of the band gap of anatase to 1.5 eV by the chemical codoping approach. Second, I will discuss the methods for accurate computation of defect properties, which is important as the defectiveness is intrinsic to the low-cost synthesized materials. I will introduce a method for calculation of defect formation energies by minimizing the error due to the ``band-gap problem'' of the density functional theory. I will also discuss approaches to mitigating the effects of defects, e.g., by passivation.

  15. Siderophile and chalcophile element abundances in oceanic basalts, Pb isotope evolution and growth of the earth's core

    NASA Technical Reports Server (NTRS)

    Newsom, H. E.; White, W. M.; Jochum, K. P.; Hofmann, A. W.

    1986-01-01

    The hypothesis that the mantle Pb isotope ratios reflect continued extraction of Pb into the earth's core over geologic time is evaluated by studying the depeletion of chalcophile and siderophile elements in the mantle. Oceanic basalt samples are analyzed in order to determine the Pb, Sr, and Nd isotropic compositions and the abundances of siderophile and chalcophile elements and incompatible lithophile elements. The data reveal that there is no systematic variation of siderophile or chalcophile element abundances relative to abundances of lithophile elements and the Pb/Ce ratio of the mantle is constant. It is suggested that the crust formation involves nonmagmatic and magmatic processes.

  16. Composition of the earth's upper mantle-I. Siderophile trace elements in ultramafic nodules

    USGS Publications Warehouse

    Morgan, J.W.; Wandless, G.A.; Petrie, R.K.; Irving, A.J.

    1981-01-01

    Seven siderophile elements (Au, Ge, Ir, Ni, Pd, Os, Re) were determined by radiochemical neutron activation analysis in 19 ultramafic rocks, which are spinel lherzollites-xenoliths from North and Central America, Hawaii and Australia, and garnet Iherzolitexenoliths from Lesotho. Abundances of the platinum metals are very uniform in spinel lherzolites averaging 3.4 ?? 1.2 ppb Os, 3.7 ?? 1.1 ppb Ir, and 4.6 ?? 2.0 ppb Pd. Sheared garnet lherzolite PHN 1611 has similar abundances of these elements, but in 4 granulated garnet lherzolites, abundances are more variable. In all samples, the Pt metals retain cosmic ( Cl-chondrite) ratios. Abundances of Au and Re vary more than those of Pt metals, but the Au/Re ratio remains close to the cosmic value. The fact that higher values of Au and Re approach cosmic proportions with respect to the Pt metals, suggests that Au and Re have been depleted in some ultramafic rocks from an initially chondrite-like pattern equivalent to about 0.01 of Cl chondrite abundances. The relative enrichment of Au and Re in crustal rocks is apparently the result of crust-mantle fractionation and does not require a special circumstance of core-mantle partitioning. Abundances of moderately volatile elements Ni, Co and Ge are very uniform in all rocks, and are much higher than those of the highly siderophile elements Au, Ir, Pd, Os and Re. When normalized to Cl chondrites, abundances of Ni and Co are nearly identical, averaging 0.20 ?? 0.02 and 0.22 ?? 0.02, respectively; but Ge is only 0.027 ?? 0.004. The low abundance of Ge relative to Ni and Co is apparently a reflection of the general depletion of volatile elements in the Earth. The moderately siderophile elements cannot be derived from the same source as the highly siderophile elements because of the marked difference in Cl chondrite-normalized abundances and patterns. We suggest that most of the Ni, Co and Ge were enriched in the silicate by the partial oxidation of pre-existing volatile-poor Fe-Ni, whereas the corresponding highly siderophile elements remained sequestered by the surviving metal. The highly siderophile elements may have been introduced by a population of ~103 large (~1022 g) planetisimals, similar to those forming the lunar mare basins. ?? 1981.

  17. Environmental Inorganic Geochemistry Group

    E-print Network

    Tobar, Michael

    mining: the mine site as a pollution source 0930 The role of water ­ an exceptional substance 1000Environmental Inorganic Geochemistry Group Environmental Geochemistry of Mine Site Pollution. Sustainability in mining requires that pollution issues are addressed from the planning stage, through operations

  18. Principals of Geochemistry

    NSDL National Science Digital Library

    Scott Prof. Wood

    This resource is the homepage of a geochemistry course taught by Professor Scott Wood at the University of Idaho. The homepage has links to lecture topics, a course outline, and tests with answers. Geochemistry students will find the site helpful for review or clarification of various topics.

  19. Assessing the utility of trace and rare earth elements as biosignatures in microbial iron oxyhydroxides

    NASA Astrophysics Data System (ADS)

    Heim, Christine; Simon, Klaus; Ionescu, Danny; Reimer, Andreas; De Beer, Dirk; Quéric, Nadia-Valérie; Reitner, Joachim; Thiel, Volker

    2015-02-01

    Microbial iron oxyhydroxides are common deposits in natural waters, recent sediments and mine drainage systems and often contain significant accumulations of trace and rare earth elements (TREE). TREE patterns are widely used to characterize minerals and rocks, and to elucidate their evolution and origin. Whether and which characteristic TREE signatures distinguish between a biological and an abiological origin of iron minerals is still not well understood. Long-term flow reactor studies were performed in the Äspö Hard Rock Laboratory to investigate the development of microbial mats dominated by iron-oxidizing bacteria, namely Mariprofundus sp. and Gallionella sp. The experiments investigated the accumulation and fractionation of TREE under controlled conditions and enabled us to assess potential biosignatures evolving within the microbial iron oxyhydroxides. Concentrations of Be, Y, Zn, Zr, Hf, W, Th, Pb, and U in the microbial mats were 1e3- to 1e5-fold higher than in the feeder fluids whereas the rare earth elements and Y (REE+Y) contents were 1e4 and 1e6 fold enriched. Except for a hydrothermally induced Eu anomaly, the normalized REE+Y patterns of the microbial iron oxyhydroxides were very similar to published REE+Y distributions of Archaean Banded Iron Formations. The microbial iron oxyhydroxides from the flow reactors were compared to iron oxyhydroxides that were artificially precipitated from the same feeder fluid. These abiotic and inorganic iron oxyhydroxides show the same REE+Y distribution patterns. Our results indicate that the REE+Y mirror quite exactly the water chemistry, but they do not allow to distinguish microbially mediated from inorganic iron precipitates. All TREE studied showed an overall similar fractionation behavior in biogenic, abiotic and inorganic iron oxyhydroxides. Exceptions are Ni and Tl, which were only accumulated in the microbial iron oxyhydroxides and may point to a potential usage of these elements as microbial biosignatures.

  20. 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.

  1. PII S0016-7037(02)01117-1 Diopside-bearing EL6 EET 90102: Insights from rare earth element distributions

    E-print Network

    PII S0016-7037(02)01117-1 Diopside-bearing EL6 EET 90102: Insights from rare earth element a study of the rare earth element (REE) distributions in EET 90102, with a specific emphasis on diopside or rare in other terrestrial or extra- terrestrial rocks. Typically, lithophile elements form sulfide

  2. Siderophile Element Partitioning between Cohenite and Liquid in Fe-Ni-S-C System and Implications for Geochemistry of Planetary Cores and Mantles

    NASA Astrophysics Data System (ADS)

    Buono, A. S.; Dasgupta, R.; Walker, D.

    2011-12-01

    Secular cooling of terrestrial planets is known to cause crystallization of a solid inner core from metallic liquid core. Fractionation of light and siderophile elements is important during such crystallization for evolution of outer core and possible core-mantle interaction. Thus far studies focused on a pure Fe inner core in simple binary systems but the effects of possible formation of a carbide inner core component on siderophile element partitioning in a multi-component system has yet to be looked at in detail. We investigated the effects of pressure and S content on partition coefficients (D) between cohenite and liquid in the Fe-Ni-S-C system. Multi-anvil experiments were performed at 3 and 6 GPa at 1150 °C, in an Fe-rich mix containing a constant C and Ni to which S contents of 0, 5, and 14 wt.% were added. All the mixes were doped with W, Re, Os, Pt, and Co. Samples were imaged and analyzed for Fe, Ni, S, and C using an EPMA. Fe, Ni, and trace elements were analyzed using a LA-ICP-MS. All the experiments produced cohenite and Fe-Ni-C±S liquid. Compared to solid-Fe/melt Ds [1-2], cohenite/melt Ds are lower for all elements except W. The light element (S+C) content of the liquid is the dominant controlling factor in siderophile element partitioning between cohenite and liquid as it is between crystalline Fe and liquid. In the cohenite-metallic melt experiments, D Ni decreases as S+C increases. Ni is excluded from the crystallizing solid if the solid is cohenite. We also find that in the Fe-Ni-S-C system, cohenite is stabilized to higher P than in the Fe-S-C system [3-5]. Similar to the Fe-metallic liquid systems the non-metal avoidance model [6] is applicable to the Fe3C-metallic liquid system studied here. Our study has implications for both the cores of smaller planets and the mantles of larger planets. If inner core forms a cohenite layer we would predict that depletions in the outer core will be less than they might be for Fe metal crystallization. For the mantle of the earth, which is thought to become Fe-Ni metal-saturated as shallow as 250 km, the sub-system Fe-Ni + C + S becomes relevant and Fe-Ni carbide rather than metallic Fe-Ni alloy may become the crystalline phase of interest. Our study implies that because the partition coefficients between cohenite and Fe-C-S melts are significantly lower than those between Fe-metal and S-rich liquid, in the presence of cohenite and Fe-C-S melt in the mantle, the mantle budget of Ni, Co, and Pt may be dominated by Fe-C-S liquid. W, Re, and Os will also be slightly enriched in C-rich Fe-Ni liquid over cohenite if the metal sub-system of interest is S-free. [1] Chabot et al., GCA 70, 1322-1335, 2006 [2] Chabot et al., GCA 72, 4146-4158, 2008 [3] Chabot et al., Meteorit. Planet. Sci. 42, 1735-1750, 2007 [4] Stewart et al., EPSL 284, 302-309, 2009 [5] Van Orman et al., EPSL 274, 250-257, 2008 [6] Jones, J.H., Malvin, D.J., Metall Mater Trans B 21, 697-706, 1990

  3. Rare earth elements in sinters from the geothermal waters (hot springs) on the Tibetan Plateau, China

    NASA Astrophysics Data System (ADS)

    Feng, Jin-Liang; Zhao, Zhen-Hong; Chen, Feng; Hu, Hai-Ping

    2014-10-01

    The mineralogical and geochemical composition of sinters from the geothermal areas on the Tibetan Plateau was determined. They occur as siliceous, salty and calcareous sinters but biogenic siliceous sinters were also found. The analyses indicate that there are no distinct inter -element relationships between individual rare earth elements (REEs) and other elements. Formed from the same geothermal water, the mineralogical and chemical composition of the sinters is influenced by their genesis and formation conditions. The REE distributions depend on the origin of the sinters. Fe-Mn phases in sinters tend to scavenge more REEs from geothermal water. Neither the REE fractionation nor the Ce anomaly seems to be associated with Fe-Mn phases in the sinters. The fourth tetrads of some sinters display weak W-type (concave) effects. In contrast, the third tetrads present large effects in some sinters due to positive Gd anomalies. The origin of the positive Eu anomalies in some sinters seems to be caused by preferential dissolution of feldspars during water-rock interaction. The complexing ligands in geothermal water may contribute significantly to the fractionation of REEs in sinters. The dominant CO32- and HCO3- complexing in geothermal water favors enrichment of heavy REEs in calcareous sinters.

  4. 'Nano' Morphology and Element Signatures of Early Life on Earth: A New Tool for Assessing Biogenicity

    NASA Technical Reports Server (NTRS)

    Oehler, D. Z.; Mostefaoui, S.; Meibom, A.; Selo, M.; McKay, D. S.; Robert, F.

    2006-01-01

    The relatively young technology of NanoSIMS is unlocking an exciting new level of information from organic matter in ancient sediments. We are using this technique to characterize Proterozoic organic material that is clearly biogenic as a guide for interpreting controversial organic structures in either terrestrial or extraterrestrial samples. NanoSIMS is secondary ion mass spectrometry for trace element and isotope analysis at sub-micron resolution. In 2005, Robert et al. [1] combined NanoSIMS element maps with optical microscopic imagery in an effort to develop a new method for assessing biogenicity of Precambrian structures. The ability of NanoSIMS to map simultaneously the distribution of organic elements with a 50 nm spatial resolution provides new biologic markers that could help define the timing of life s development on Earth. The current study corroborates the work of Robert et al. and builds on their study by using NanoSIMS to map C, N (as CN), S, Si and O of both excellently preserved microfossils and less well preserved, non-descript organics in Proterozoic chert from the ca. 0.8 Ga Bitter Springs Formation of Australia.

  5. Accumulation of rare earth elements in human bone within the lifespan.

    PubMed

    Zaichick, Sofia; Zaichick, Vladimir; Karandashev, Vasilii; Nosenko, Sergey

    2011-02-01

    For the first time, the contents of rare earth elements (REEs) in a rib bone of a healthy human were determined. The mean value of the contents of Ce, Dy, Er, Gd, La, Nd, Pr, Sm, Tb, and Yb (10 elements out of 17 total REEs), as well as the upper limit of means for Ho, Lu, Tm, and Y (4 elements) were measured in the rib bone tissue of 38 females and 42 males (15 to 55 years old) using inductively coupled plasma mass spectrometry (ICP-MS). We found age-related accumulation of REEs in the bone tissue of healthy individuals who lived in a non-industrial region. It was calculated that during a lifespan the content of REEs in a skeleton of non-industrial region residents may increase by one to two orders of magnitude. Using our results as indicative normal values and published data we estimated relative Gd accumulation in the bone tissue of patients according to magnetic resonance imaging with contrast agent and La accumulation in the bone tissue of patients receiving hemodialysis after treatment with lanthanum carbonate as a phosphate binder. It was shown that after such procedures contents of Gd and La in the bone tissue of patients are two to three orders of magnitude higher than normal levels. In our opinion, REEs incorporation may affect bone quality and health similar to other potentially toxic trace metals. The impact of elevated REEs content on bone physiology, biochemistry and morphology requires further investigation. PMID:21173982

  6. Chemical properties of rare earth elements in typical medical waste incinerator ashes in China.

    PubMed

    Zhao, Lijuan; Zhang, Fu-Shen; Zhang, Jingxin

    2008-10-30

    Medical waste (MW) ashes from different types of MW incinerators were examined to detect the characteristics and environmental impact of rare earth elements (REEs). The results showed that total REE contents in the ash samples ranged from 10.2 to 78.9 mg/kg. REEs in bottom ash were apparently higher than those in fly ash. Average REE contents in the ashes followed the sequence of Ce>La>Nd>Y>Gd>Pr>Sm>Dy>Er>Yb>Ho>Eu>Tb>Lu>Tm. Some of the elements, such as Sm, Dy, Ho, Er, Yb in the ash samples were in normal or nearly normal distribution, but Y, La, Ce, Pr, Nd, Eu, Gd, Tb, Tm, Lu were not normally distributed, indicating some of the ash samples were enriched with these elements. Crust-normalized REE patterns indicated that two types of the MW ashes were obviously enriched with Gd and La. Sequential extraction results showed that REEs in the ash mainly presented as residual fraction, while exchangeable and carbonate fractions were relatively low. DTPA- and EDTA-extraction tests indicated that REEs in the MW ashes were generally in low bioavailability. PMID:18329796

  7. Effects of rare earth elements La and Yb on the morphological and functional development of zebrafish embryos.

    PubMed

    Cui, Jun'an; Zhang, Zhiyong; Bai, Wei; Zhang, Ligang; He, Xiao; Ma, Yuhui; Liu, Yan; Chai, Zhifang

    2012-01-01

    In recent years, with the wide applications and mineral exploitation of rare earth elements, their potential environmental and health effects have caused increasing public concern. Effect of rare earth elements La and Yb on the morphological and functional development of zebrafish embryos were studied. The embryos were exposed to La3+ or Yb3+ at 0, 0.01, 0.1, 0.3, 0.5 and 1.0 mmol/L, respectively. Early life stage parameters such as egg and embryo mortality, gastrula development, tail detachment, eyes, somite formation, circulatory system, pigmentation, malformations, hatching rate, length of larvae and mortality were investigated. The results showed La3+ and Yb3+ delayed zebrafish embryo and larval development, decreased survival and hatching rates, and caused tail malformation in a concentration-dependent way. Moreover, heavy rare-earth ytterbium led to more severe acute toxicity of zebrafish embryo than light rare-earth lanthanum. PMID:22655378

  8. Insights of ridge-flank hydrothermal processes through minor and trace element geochemistry of sediment pore fluids from IODP Site 1301

    NASA Astrophysics Data System (ADS)

    Hulme, S. M.

    2005-12-01

    The volumetric flux of seawater that flows through the oceanic crust rivals that which flows from rivers into the oceans. As seawater or formation fluid circulates through oceanic basement it is warmed and reacts with basalt and secondary minerals. In addition, diffusive exchange with overlying pore fluids may also impact the composition of the circulating fluid in basement. This interplay among seawater (formation fluid) reaction with basalt, diffusive exchange, and warming continues to the point of egress. How this seawater circulates through the crust and the chemical, mass, and thermal fluxes that it generates was the focus for drilling IODP Leg 301 on the eastern flank of the Juan de Fuca Ridge on 3.5-m.y.-old crust. We have conducted a comprehensive series of chemical analyses on pore waters from IODP Expedition 301 to constrain the composition of the formation fluid within the upper-most basaltic basement and compared it to the composition from nearby springs and borehole data. Sediments were recovered from IODP Holes 1301C (29 samples) and 1301D (9 samples) using the advanced piston coring (APC) technique. Sediments for pore fluid extraction were collected throughout the sediment column with a greater vertical resolution at the sediment-basement contact. Pore fluids were extracted in a nitrogen atmosphere to minimize potential oxidation reactions. Shipboard analyses included Ca, Mg, Alkalinity, pH, chlorinity, ammonium, phosphate, sulfate, K, Si, Li, B, Mn, Fe, Sr, DIC, total C, and Ba. Subsequent sample analysis with a Finnagin Element 2 high-resolution ICP-MS included: the trace elements Rb, Cs, Ba, Y, Cd and U; transition metals Mo, V, Cr, Co, Cu, Ni and Zn; and the complete suite of rare earth elements (REE). These data provide additional constraints to determine diffusive fluxes between the sediment and basement reservoirs, allowing us to refine models that constrain the rate of fluid flow within the crust and re-affirm the directionality of flow along the buried ridge. Coupling the compositions of the formation fluids with recent advances in thermodynamic databases for low temperature mineral formation-dissolution provides an avenue not only for understanding present crustal conditions, but also for being able to envision conditions at which particular reactions occur.

  9. Partition coefficients for rare earth elements in mafic minerals of high silica rhyolites: the importance of accessory mineral inclusions

    Microsoft Academic Search

    P MICHAEL

    1988-01-01

    REE concentrations of mafic mineral separates from high-silica rhyolites measured by INAA are high and variable compared to electron microprobe analyses of the minerals themselves. The mafic phases commonly contain inclusions or have adhering grains of accessory rare earth element (REE)-rich minerals. Optical and electron microscopic observation revealed discrete grains of chevkinite (rare earth titano-silicate) included within clinopyroxenes from the

  10. Development and application of a sensitive and rapid analytical method to determine the rare-earth elements in surface waters

    Microsoft Academic Search

    Gwendy E. M. Hall; Judy E. Vaive; John W. McConnell

    1995-01-01

    A new cost-effective method to determine the 14 rare-earth elements (REE's) in waters to levels as low as 0.2–1.0 ng l?1 (ppt) has been established. Inductively coupled plasma mass spectrometry (ICP-MS) is used for measurement following automated preconcentration using the Dionex® MetPac CC-1 resin of iminodiacetate functionality. The free REE ion is chelated onto the resin while alkali and alkaline-earth

  11. Bounding dispersion analysis for rare-earth elements as it pertains to the Engineering Demonstration System surrogate testing

    Microsoft Academic Search

    1990-01-01

    An analysis of a bounding atmospheric dispersion of a rare-earth oxide shows that the off-site concentrations are significantly less than established health guidelines and ground deposition will not result in an impact to the food chain. For these reasons, we conclude that the use of rare-earth elements in the Engineering Demonstration System (EDS) will have no health impact to the

  12. Bounding dispersion analysis for rare-earth elements as it pertains to the Engineering Demonstration System surrogate testing

    SciTech Connect

    Ernst, K.

    1990-01-01

    An analysis of a bounding atmospheric dispersion of a rare-earth oxide shows that the off-site concentrations are significantly less than established health guidelines and ground deposition will not result in an impact to the food chain. For these reasons, we conclude that the use of rare-earth elements in the Engineering Demonstration System (EDS) will have no health impact to the public due to atmospheric dispersion. 8 refs., 1 fig., 3 tabs.

  13. Soviet lander and Magellan data point toward Earthlike Venus geochemistry and volcanology,

    E-print Network

    Treiman, Allan H.

    Soviet lander and Magellan data point toward Earthlike Venus geochemistry and volcanology University of Arizona Tucson #12;Key conclusions about Venus from rock geochemistry (1-3) Confidence: 75% (4) Treiman 2007. #12;How similar are Venus and Earth geochemically and petrologically? How does the Venusian

  14. Light shifts and magic wavelengths for heavy alkaline earth elements: Ba and Ra

    NASA Astrophysics Data System (ADS)

    Dammalapati, U.; Santra, B.; Willmann, L.

    2012-01-01

    In this paper, we investigate light shifts of heavy alkaline earth elements barium (Ba) and radium (Ra), which are interesting for optical lattice clocks and for permanent electric dipole moment searches. Detailed knowledge is required in the design of efficient loading of atoms from a magneto-optical trap into an optical dipole trap, to facilitate Doppler cooling while trapping and to achieve longer lifetimes of the trapped atoms with reduced heating rates. The wavelength dependence of light shifts of the ns2 1S0 ground state, the nsnp 3P1 and ns(n - 1)d 1D2 excited states in barium (n = 6) and the n s2 1S0 ground state, the nsnp 3P1 and ns(n - 1)d 3D2 excited states in radium (n = 7) are calculated. Several magic wavelengths in the visible and infrared regions accessible with commercial lasers for optical dipole trapping of Ba and Ra are identified.

  15. Tracing sediment movement on semi-arid watershed using rate Earth elements

    NASA Astrophysics Data System (ADS)

    Polyakov, V.; Nearing, M. A.

    2009-04-01

    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 contribution of each unit to the total sediment yield was determined by collecting runoff and sediment, and the spatial redistribution of sediment was determined from sampling the soil surface. Average sediment yield was 1.0 t ha-1 y-1 from the entire watershed, but varied between 0.1 t ha-1 y-1 from the upper slope to 5.0 t ha-1 y-1 from the lower channel. Little re-deposition occurred in the channels indicating an effective transport system. The erosion pattern and rates were in agreement with the current morphology of the watershed, which has a well developed channel network.

  16. Investigation of rare-earth and associated elements, Zane Hills Pluton, Northwestern Alaska. Open File Report

    SciTech Connect

    Barker, J.C.

    1991-01-01

    Unverified reports of rare earth element (REE) concentrations in gold placers and radioactive mineral prospects in the Zane Hills were investigated by the U.S. Bureau of Mines as part of the Alaska critical minerals program. The Bureau mapped and sampled all of the reported or suspected REE occurrences. Dredge concentrates contain abundant uranothorianite, a mineral species which incorporates cerium subgroup REE. Bostonite dikes occur in conjunction with a multiphased zoned alkalic intrusion, however, no significant REE concentrations were found. The Zane Hills exhibit attractive exploration targets for uranium deposits, primarily in a sedimentary form. Gold may be found peripheral to the pluton in both placer and lode deposits. Resource potential of REE, however, appears limited to a placer by-product of REE-Zr-Ti that is recoverable only during large scale gold placer mining. Placer exploration of the lower Wheeler and Dakli Creeks is suggested.

  17. Fractionations of rare earth elements in plants and their conceptive model.

    PubMed

    Ding, ShiMing; Liang, Tao; Yan, JunCai; Zhang, ZiLi; Huang, ZeChun; Xie, YaNing

    2007-02-01

    Fractionations of rare earth elements (REEs) and their mechanisms in soybean were studied through application of exogenous mixed REEs under hydroponic conditions. Significant enrichment of middle REEs (MREEs) and heavy REEs (HREEs) was observed in plant roots and leaves respectively, with slight fractionation between light REEs (LREEs) and HREEs in stems. Moreover, the tetrad effect was observed in these organs. Investigations into REE speciation in roots and in the xylem sap using X-ray absorption spectroscopy (XAS) and nanometer-sized TiO2 adsorption techniques, associated with other controlled experiments, demonstrated that REE fractionations should be dominated by fixation mechanism in roots caused by cell wall absorption and phosphate precipitation, and by the combined effects of fixation mechanism and transport mechanism in aboveground parts caused by solution complexation by intrinsic organic ligands. A conceptive model was established for REE fractionations in plants based on the above studies. PMID:17393082

  18. Origin of middle rare earth element enrichment in acid mine drainage-impacted areas.

    PubMed

    Grawunder, Anja; Merten, Dirk; Büchel, Georg

    2014-01-01

    The commonly observed enrichment of middle rare earth elements (MREE) in water sampled in acid mine drainage (AMD)-impacted areas was found to be the result of preferential release from the widespread mineral pyrite (FeS2). Three different mining-impacted sites in Europe were sampled for water, and various pyrite samples were used in batch experiments with diluted sulphuric acid simulating AMD-impacted water with high sulphate concentration and high acidity. All water samples independent on their origin from groundwater, creek water or lake water as well as on the surrounding rock types showed MREE enrichment. Also the pyrite samples showed MREE enrichment in the respective acidic leachate but not always in their total contents indicating a process-controlled release. It is discussed that most probably complexation to sulphite (SO3 (2-)) or another intermediate S-species during pyrite oxidation is the reason for the MREE enrichment in the normalized REE patterns. PMID:24385183

  19. Behavior of Rare Earth Element In Geothermal Systems; A New Exploration/Exploitation Tool

    SciTech Connect

    Scott A. Wood

    2002-01-28

    The goal of this four-year project was to provide a database by which to judge the utility of the rare earth elements (REE) in the exploration for and exploitation of geothermal fields in the United States. Geothermal fluids from hot springs and wells have been sampled from a number of locations, including: (1) the North Island of New Zealand (1 set of samples); (2) the Cascades of Oregon; (3) the Harney, Alvord Desert and Owyhee geothermal areas of Oregon; (4) the Dixie Valley and Beowawe fields in Nevada; (5) Palinpion, the Philippines: (6) the Salton Sea and Heber geothermal fields of southern California; and (7) the Dieng field in Central Java, Indonesia. We have analyzed the samples from all fields for REE except the last two.

  20. X-ray fluorescence analysis of rare earth elements in rocks using low dilution glass beads.

    PubMed

    Nakayama, Kenichi; Nakamura, Toshihiro

    2005-07-01

    Major and trace elements (Na, Mg, Al, Si, P, K, Ca, Ti, Mn, Fe, Rb, Sr, Y, Zr, La, Ce, Pr, Nd, Sm, Gd, Dy, Th and U) in igneous rocks were assayed with fused lithium borate glass beads using X-ray fluorescence spectrometry. Low dilution glass beads, which had a 1:1 sample-to-flux ratio, were prepared for determination of rare earth elements. Complete vitrification of 1:1 mixture required heating twice at 1200 degrees C with agitation. Extra pure reagents containing determinants were used for calibrating standards instead of the rock standard. The calibration curves of the 23 elements showed good linearity. Furthermore, the lower limits of detection corresponding to three times the standard deviation for blank measurements were 26 mass ppm for Na2O, 6.7 for MgO, 4.5 for Al2O3, 4.5 for SiO2, 18 for P2O5, 1.1 for K2O, 4.0 for CaO, 3.9 for TiO2, 1.6 for MnO, 0.8 for Fe2O3, 0.5 for Rb, 0.2 for Sr, 0.4 for Y, 0.5 for Zr, 3.3 for La, 6.5 for Ce, 2.7 for Pr, 2.1 for Nd, 1.7 for Sm, 0.7 for Gd, 2.7 for Dy, 0.5 for Th, and 0.6 for U. Using the present method, we determined the contents of these 23 elements in four rhyolitic and granitic rocks from Japan. PMID:16038502

  1. Quantitative estimation of concentrations of dissolved rare earth elements using reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Dai, Jingjing; Wang, Denghong; Wang, Runsheng; Chen, Zhenghui

    2013-01-01

    Characteristic spectral parameters such as the wavelength and depth of absorption bands are widely used to quantitatively estimate the composition of samples from hyperspectral reflectance data in soil science, mineralogy as well as vegetation study. However, little research has been conducted on the spectral characteristic of rare earth elements (REE) and their relationship with chemical composition of aqueous solutions. Reflectance spectra of ore leachate solutions and contaminated stream water from a few REE mines in the Jiangxi Province, China, are studied for the first time in this work. The results demonstrate that the six diagnostic absorption features of the rare earths are recognized in visible and near-infrared wavelengths at 574, 790, 736, 520, 861, and 443 nm. The intensity of each of these six absorption bands is linearly correlated with the abundance of total REE, with the r2 value >0.95 and the detection limit at ?75,000 ?g/L. It is suggested that reflectance spectroscopy provides an ideal routine analytical tool for characterizing leachate samples. The outcome of this study also has implications for monitoring the environmental effect of REE mining, in particular in stream water systems by hyperspectral remote sensing.

  2. Galileo Earth approach navigation using connected-element interferometer phase-delay tracking

    NASA Technical Reports Server (NTRS)

    Thurman, S. W.

    1990-01-01

    The application of a Connected-Element Interferometer (CEI) to the navigation of the Galileo spacecraft during its encounter with Earth in December 1990 is investigated. A CEI tracking demonstration is planned for the week of November 11 through 18, 1990, from 27 days to 20 days prior to Earth encounter on December 8. During this period, the spacecraft will be tracked daily with Deep Space Network Stations 13 and 15 at Goldstone. The purpose of this work is twofold: first, to establish and define the navigation performance expected during the tracking demonstration and, second, to study, in a more general sense, the sensitivity of orbit demonstration results obtained with CEI to the data density within CEI tracking passes and to important system parameters, such as baseline orientation errors and the phase-delay measurement accuracy. Computer simulation results indicate that the use of CEI data, coupled with conventional range and Doppler data, may reduce the uncertainty in the declination of the spacecraft's incoming trajectory by 15 to 66 percent compared with the operational solution using range and Doppler data only. The level of improvement depends upon the quantity and quality of the CEI data.

  3. 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 ?m) 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 ?18O 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.

  4. Rare earth element carriers in the Shergotty meteorite and implications for its chronology

    SciTech Connect

    Lundberg, L.L.; Crozaz, G.; Zinner, E. (Washington Univ., St. Louis, MO (USA)); McKay, G. (NASA, Johnson Space Center, Houston, TX (USA))

    1988-08-01

    Ion probe measurements of the rare earth element (REE) concentrations of individual grains of the Shergotty meteorite are reported. Phases analyzed include whitlockite, apatite, baddeleyite, augite, pigeonite, maskelynite and K-rich glass. U concentrations of whitlockite and apatite crystals were also obtained. The whole rock REE pattern is dominated by whitlockite, which contains over 95% of the light rare earth elements (LREE). REE concentrations in apatite are much lower than estimated by Laul et al. (1986). All of the whitlockites have the same relative abundances of LREE. The observation, by Jones et al. (1985), of a skeletal whitlockite with LREE enrichment is not confirmed by analyses of the same grain. Pyroxene rims are not enriched in LREE. No leachable carrier, enriched in LREE and associated with pyroxene, has been found. Instead, either a laboratory contamination or a petrographically cryptic phase such as a film on grain boundaries is suspected as the carrier of LREE enrichments. Estimates of REE abundances in the Shergotty intercumulus melt indicate that a complex petrogenesis is required, in agreement with the conclusions of McKay et al. (1986a). Pyroxene distribution coefficients measured experimentally are compared with estimates from measured REE abundances in augite and pigeonite. Evolution of REE abundances in the Shergotty late-stage interstitial melt, as inferred from analyses of whitlockite, conforms with trends predicted from partitioning considerations, and requires no special processes such as metasomatism. The average U concentrations of whitlockite and apatite are respectively 540 and 1,550 ppb. Although the calcium phosphates are enriched in U, they contain less than 20% of the U in Shergotty.

  5. Rare earth element components in atmospheric particulates in the Bayan Obo mine region

    SciTech Connect

    Wang, Lingqing, E-mail: wanglq@igsnrr.ac.cn; Liang, Tao, E-mail: liangt@igsnrr.ac.cn; 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 ?m (PM{sub 10}) 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{sup 3}, and those for PM{sub 10} were 42.8 and 68.9 ng/m{sup 3}, in August 2012 and March 2013, respectively. Enrichment factor was calculated for all 14 REEs in the TSP and PM{sub 10} 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 PM{sub 10} 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{sub N}/Yb{sub N}, La{sub N}/Sm{sub N}, Gd{sub N}/Yb{sub N}). - Highlights: • TSP and PM{sub 10} samples were collected to analyze the levels and distributions of REE. • Enrichment factors indicated that REE enrichment was caused by anthropogenic sources. • The distribution of REEs showed a strong gradient in the prevailing wind direction. • Obvious fractionation between LREEs and HREEs is observed in atmospheric particulates.

  6. Extraction of rare-earth elements by crown ethers from acid solutions into 1,1,7-trihydrododecafluoroheptanol

    Microsoft Academic Search

    S. V. Demin; V. I. Zhilov; A. Yu. Tsivadze; V. V. Yakshin; O. M. Vilkova

    2009-01-01

    Extraction of rare-earth elements from acid solutions in the 1,1,7-trihydrododecafluoroheptanol-water system was studied using\\u000a crown ethers: dicyclohexano-18-crown-6 (DCH18C6; isomer A) and di-tert-butyldicyclohexano-18-crown-6 (DTBDCH18C6). All other conditions being equal, the extractability of rareearth elements by\\u000a DTBDCH18C6 is far higher than for DCH18C6 itself. Trifluoroacetic and trichloroacetic acids increase metal distribution ratios.\\u000a The distribution ratios for the cerium rare earths considerably exceed

  7. Geochemistry all around us

    NSDL National Science Digital Library

    Andrew Knudsen

    This activity is actually a series of labs/field trip exercises I ran with my advanced geochemistry class a year ago. For this class, we went on a number of field trips to sample a number of local waters, including, High Cliff State Park, where the Niagran Escarpment is present, a local wetland reserve, Lake Winnebago, the Fox River (downstream from Lake Winnebago), and finally a nearby cave in the dolostone of the Niagran Escarpment. We tested these waters for a few relatively straightforward properties: hardness, alkalinity, pH, and dissolved oxygen. In the future I am going to expand these analyses to include analysis on our AA, and possibly sending samples away for ICP analysis on a suite of elements. These sampling trips followed our course materials looking at the thermodynamics of mineral solubility and the interaction of water with the atmosphere. Students were able to easily recognize how these waters were different, and were able to make reasonable hypotheses to explain these differences. Furthermore, because this was the first time I had sampled these waters (this was in my first year), I didn't know the answer, so students were themselves forced to determine whether their results were reasonable or not. As an additional note, I should credit Tony Hoch, my predecessor here at LU. Much of the material I used in these labs evolved from labs he had run while at LU.

  8. Tracing irradiation-induced defect state of monazite by photoluminescence of rare Earth elements

    NASA Astrophysics Data System (ADS)

    Panczer, G.; Seydoux-Guillaume, A. M.; Montel, J. M.; Champagnon, B.

    2003-04-01

    Natural monazite is known in contrast to zircon, to almost never be found in the metamict state (Ewing, 1975) despite the fact that it received intensive radiation doses during geologic history by U and Th incorporation. Radiation damages in natural monazite seems to be limited to isolated domains within the crystal (Meldrum et al., 1998). Such property controlled the fact that the monazite lattice is easily healed even at low temperature as it was shown by TEM, XRD and Raman spectrometry (Seydoux-Guillaume et al., 2002). In order to estimate the degree of disorder and the healing of defects we used trivalent neodymium as an internal luminescent probe (Gaft et al., 2001). As a matter of fact the radiative electronic transitions of rare earth elements are very sensible to the short-range crystallographic order around them. Three natural monazites thermally untreated and quenched at 450, 500, 700, 800 and 1000^oC were analyzed under 514 nm Argon laser excitation with a Renishaw microspectrometer. Nd3+ emission was recorded in the range of 750 nm to 1 ?m. The ^4F3/2 rightarrow ^4I9/2 transition parameters (position and width) show that 1) the position of the Stark levels do not change during thermal treatment, and 2) that the emission line widths decrease continuously (from 25 to 37%) from room temperature to 1000^oC. These results indicates that before annealing, sub sites of Nd were present with slight different environments induced by internal irradiation induced displacement of ions around them (short range disorder). After thermal treatment a continuous reorganization of the lattice occurs up to 1000^oC with quite strong rearrangement of the environment around the rare-earth leading to a decrease of the Nd sub site number. Thus, the luminescent probe reveals that defect healing continue at much higher temperatures than what was previously reported indicating that luminescence is a very sensible tool to appreciate the degree of disorder in mineral phases. Gaft M., Panczer G., Reisfeld R. &Uspensky E. (2001) Laser-induced time-resolved luminescence as a tool for rare-earth element identification in minerals., Phys. Chem. Minerals, 28, 347-363.

  9. Subduction Zone Redox and the Deep Earth Cycles of Sulfur and Chalcophile Elements

    NASA Astrophysics Data System (ADS)

    Canil, D.

    2013-12-01

    Subduction at convergent plate margins is a return flux to the mantle of rocks influenced by weathering, hydrothermal activity, atmospheric exchange, or bio-mineralization in the exosphere. The latter exogenic processes modify the long-term abundance and behaviour of certain elements in the deeper earth that can be traced over time in the chemistry of mantle-derived magmas. The redox budget of subduction is controlled by the flux of oxidized versus reduced forms of Fe, S, H, or C, and impacts the long-term evolution of oxygen on the planet, critical for life in the exosphere. In particular, the sulfur cycle is specifically tied to the evolution of oxygen on Earth's surface over time and critical to biogeochemical cycles on the surface. The behaviour of sulfur in the exogenic system is well-studied and fairly well understood using sedimentary records. An originally sulfidic ocean on Earth gave way with time and oxygenation to one that is sulfate dominated over the last two billion years. In contrast, far less is known of the deep earth cycle of S, and more so its history. The record of the endogenic cycle can only be monitored via what comes out of the mantle (magmas and their gases), or what goes down via subduction (hydrothermally-altered or weathered subducted lithosphere). Interest in the endogenic cycle of S is not new but several outstanding conundrums remain for sulfur in arc magmas that point to the importance of the subduction process. A hitherto ignored component of the paradox of the sulfur cycle is the sedimentary veneer that sits atop the subducted oceanic basalt crust. Compilations show only 0.12 wt% S in altered ocean basalt crust, but up to 10 times that amount in oceanic sediments, tied to their Fe content (in pyrite). These abundances may seem trivial, but the behaviour of this small amount of S in subduction is not fully appreciated and its oxidation potential in the arc mantle is enormous. The conversion of subducted sulfide to sulfate is a 8-electron change in redox state, with significant oxidation/ reduction capacity. The concomitant higher fO2 can in turn facilitate the mobility and/or extraction of chalcophile metals from the arc mantle into magmas by the melting process in arcs. Sedimentary records show that through most of Earth's history sulfur has mostly been subducted in reduced form as sulfide. The fate of sulfide in ocean sediments during subduction (and subsequent dehydration or melting) has not been thoroughly investigated, nor its interplay with other redox couples (C, H, Fe) in sediments, subducted basalt or in the mantle. I examine the redox controls on sulfate versus sulfide stability in subducted oceanic crust, and their disposition relative to other redox couples in the mantle. Sulfate-sulfide equilibria impact the fate of sulfur and chalcophile elements in subducted lithologies, especially if dehydrated or melted depending on a variety subduction P-T trajectories. In this light, new high P-T experiments show the utility of Cu as a proxy for S in the subduction system . These proxies can potentially be applied to examine the deep S cycle, subduction redox and its role in arc magmatism over geologic time.

  10. Rare earth element sources and modification in the Lower Kittanning coal bed, Pennsylvania: implications for the origin of coal mineral matter and rare earth element exposure in underground mines

    Microsoft Academic Search

    Steven J. Schatzel; Brian W. Stewart

    2003-01-01

    In this study, we examine the variations in rare earth elements (REE) from the Lower Kittanning coal bed of eastern Ohio and western Pennsylvania, USA, in an attempt to understand the factors that control mineral matter deposition and modification in coal, and to evaluate possible REE mixed exposure hazards facing underground mine workers. The results of this study suggest that

  11. Solution properties of rare earth elements in silicate melts: Inferences from immiscible liquids

    SciTech Connect

    Ellison, A.J.G.; Hess, P.C. (Brown Univ., Providence, RI (USA))

    1989-08-01

    The partitioning behavior of rare earth elements (REE) between immiscible silicate liquids was investigated as a function of temperature and total REE oxide concentration. REE preferentially partition into the end-member liquids that are rich in network-modifying cations, with two-liquid partition coefficients greater than any other cation. The two-liquid partition coefficients of REE in a given experiment are essentially identical to one another. No evidence was seen to suggest that the solution mechanisms of REE in high-silica liquids vary with differences in their ionic radii. Two-lattice models of trace element solution behavior fail to remove the compositional dependence of REE two-liquid partition coefficients due to the assumption that all network-forming and network-modifying cations mix ideally with one another. As a result, it is probably incorrect to derive physical interpretations from the results of the application of two-lattice models. The results are applied to the origins of the LREE-enriched phenocryst-matrix partition coefficients seen for some ferromagnesian minerals in high-silica rhyolites. Since liquids with extremely high concentrations of T-O-T linkages do not strongly discriminate between the REE on the basis of their ionic radii, the anomalous REE crystal-matrix partition coefficient patterns are best explained as the result of contamination of these minerals by LREE accessory phases.

  12. Effects of exogenous rare earth elements on phosphorus adsorption and desorption in different types of soils.

    PubMed

    Wang, Lingqing; Liang, Tao

    2014-05-01

    Phosphorus (P) is an important biogeochemical element and the environmental fate of P receives increasing attention. Through batch equilibration experiments, the adsorption and desorption of P in the absence and presence of exogeneous rare earth elements (REEs) were investigated in five types of agricultural soil samples collected from China. The results showed that the addition of different doses of REEs had influences on P adsorption processes in the soils, and there were differences in different soil types and different P concentrations of the P solutions. The amount of P adsorption tended to decline when the five types of soils were amended with low concentrations of REEs. The characteristics of P adsorption were more complicated when high concentrations of REEs were added to the different soils. Affected by the high concentrations of REEs, when the P concentration of the P solution added to soils was less than 20 mg L(-1), the rate of P adsorption tended to increase in all the five types of soils. However, when the P concentration of the P solution added to soil was greater than 30 mg L(-1), the rate of P adsorption tended to decrease. The Langmuir equation fitted P adsorption in all the five types of soils well. Compared with the control, when soil samples were amended with REEs, the P desorption rates of the five types of soils increased. PMID:24342358

  13. The properties of Sn9Zn lead-free solder alloys doped with trace rare earth elements

    Microsoft Academic Search

    C. M. L. Wu; D. Q. Yu; C. M. T. Law; L. Wang

    2002-01-01

    The Sn-Zn alloys have been considered as lead-free solders. It is well known that their poor properties of wetting and oxidation\\u000a resistance are the main problems to prevent them from becoming commercially viable solders. In this paper, trace rare earth\\u000a (RE) elements of mainly Ce and La have been used as alloying elements into the Sn-9Zn alloy. The results indicated

  14. Determination of rare earth elements in geological materials by inductively coupled argon plasma\\/atomic emission spectrometry

    Microsoft Academic Search

    J. G. Crock; F. E. Lichte

    1982-01-01

    Inductively coupled argon plasma\\/optical emission spectrometry (ICAP\\/OES) is useful as a simultaneous, multielement analytical technique for the determination of trace elements in geological materials. A method for the determination of trace-level rare earth elements (REE) in geological materials using an ICAP 63-channel emission spectrometer is described. Separation and preconcentration of the REE and yttrium from a sample digest are achieved

  15. Mobility of rare earth elements in the system soils–plants–groundwaters: a case study of an arid area (Oman)

    Microsoft Academic Search

    Khadija Semhi; Osman A. E. Abdalla; Salah Al Khirbash; Tabisam Khan; Salim Asaidi; Sardar Farooq

    2009-01-01

    Groundwater samples from six wells and various species of plants from soils developed on ophiolites were collected from an\\u000a arid area (AlKhod area, Oman) and analyzed for trace elements including rare earth elements (REEs). The distribution patterns\\u000a of REEs in plants indicated an enrichment in middle REEs (MREEs?=?Sm to Dy) and heavy REEs (HREEs?=?Ho to Lu), when they are\\u000a normalized

  16. Using rare earth elements for the identification of the geographic origin of food

    NASA Astrophysics Data System (ADS)

    Meisel, T.; Bandoniene, D.; Joebstl, D.

    2009-04-01

    The European Union defined regimes within the Protected Geographical Status (PGS) framework to protect names of regional food specialities. Thus only food produced in a specific geographical area with a specific way of production or quality can be protected by a protected geographical indication (PGI) label. As such Styrian Pumpkin Seed Oil has been approved with this label, but as with many other high priced regional specialities, fraud cannot be excluded or nor identified. Thus the aim of this work is, to develop an analytical method for the control of the geographic origin of pumpkin seed oil and also to test the method for other protected products. The development of such a method is not only of interest for scientists, but also of importance for the consumer wanting to know the origin of the food products and the assurance of the purity and quality. The group of rare earth elements (REE) in plants also have a characteristic distribution pattern similar to upper crustal REE distributions. Since the REE concentrations are extremely low in pumpkin seed oil (ppt to low ppb), ICP-MS was the only sensitive tool able to produce validated results. The carrier of the REE are most likely small particles distributed within the pumpkin seed oil. Unlike, e.g., olive oil, pumpkin seed oil is bottled and sold unfiltered, which makes this Styrian speciality an interesting sampling target. As pumpkin seed oils from different geographic origin show variable trace element and rare earth distribution patterns, is should possible to trace the origin of these oils. In the current project pumpkin seeds from different regions in Austria and from abroad were sampled. The trace element patterns in the extracted oil of these seeds were determined and a preliminary classification with discriminate analysis was successfully done on a statistical basis. In addition to the study of the geographic origin it was demonstrated that REE distribution patterns can also be used for the identification of adulteration of high priced pumpkin seed oil with cheap neutral tasting refined oils. Interestingly enough, the variations of the REE patterns between oils from different regions are much more pronounced than their host soils. Thus we assume that microbiological processes in the rhizosphere are in control of the REE uptake into the plant. Regional variations of the microbiological composition of the soils and probably not only a priori the bulk soil composition of the minerals in the soil are the cause of the regional variations making it possible to identify the geographic origin of pumpkin seeds and as a consequence the pumpkin seed oil.

  17. Bioavailable concentrations of germanium and rare earth elements in soil fractions

    NASA Astrophysics Data System (ADS)

    Hentschel, Werner; Wiche, Oliver

    2015-04-01

    As there is an increasing demand for germanium and the rare earth elements due to their diverse application in modern technologies (optical cables, permanent magnets in wind power stations), there is an interest to investigate a new approach to extract these ubiquitous but disperse existing elements - via Phytomining. But before this method can be established, a thorough understanding of processes regarding the intake of germanium (Ge) and the rare earth elements (REEs) is necessary. The aim of this work was to get insights or hints on correlations between the concentrations and the fractionation of Ge and REEs in the soil and the concentrations in plants - in other words we wanted to conduct research on bioavailable concentrations of Ge and REEs in soil fractions. On 18 sites situated around Freiberg, Saxony we took samples of soil and plants. To extract the elements from the plant material a decomposition with hydrofluoric acid was used. The soil samples was examined by a sequential extraction with seven steps (mobile, carbonatic, oxidisable, amorphic oxides, crystalline oxides, phytoliths and secondary clay minerals, residual or siliceous). The amounts of the REEs showed a high correlation between each other, so neodymium can be regarded as a proxy for all REEs. The average total amount of Ge in the soil samples was around 1.45 mg/kg, the one of neodymium (Nd) was around 25 mg/kg. Both values equal the overall average in the earth crust. Concerning the Ge concentration in soil the residual siliceous fractions constituted for 70% of total, whereas the fractions V and VI - dedicated as crystalline oxides and phytoliths/secondary clay minerals - made out for 25%. Only 5% of the total amount of Ge in soil accounted for the fractions I to IV. There was found a statistical significant correlation between the absolute Ge concentrations in these latter soil fractions with the Ge concentration in plant material of the same site. Therefore it seems that the fractions I to IV could be regarded as a proxy for the bioavailable pool of Ge in soils. Concerning Nd the residual siliceous fractions made out for 60% of the total, whereas the fraction III (oxidisable) constitutes for 30%. The remaining 10% accounted for the other soil fractions. No correlation between the concentration in one soil fraction and the concentration in plant material from the same site could be found. There was also no correlation between the total amount in soil and the concentration in plant material from the same site neither for the REEs nor for Ge. These results can give only hints on the processes regarding the mobilisation of the bioavailable pool of Ge and REEs. Further investigations are necessary and will be taken in the PhytoGerm project.

  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. PMID:23978671

  19. Earth

    NSDL National Science Digital Library

    This lithograph depicts a view of Earth taken from Apollo 10 during its journey to the Moon in May 1969. False-color satellite images showing chlorophyll concentration, sea surface temperature, topography, and ozone concentration are also featured. The images are accompanied by a brief description, some statistical facts, and a list of important dates in the history of Earth exploration.

  20. Performance and Blood Characteristics of Pre-pubertal Rabbits Fed Varied Levels of Dietary Rare Earth Element (REE)

    Microsoft Academic Search

    O. A. Adu; M. K. Ladipo; O. A. Adebiyi; A Akinfemi; F. A. Igbasan

    4 Abstract: In a feeding trial that lasted 20 weeks, 35 weanling female rabbit of an average weight of 510g were used to assess the effect of inclusion of different levels of Rare Earth Element (REE) 0, 100, 200,300 and 400ppm inclusion levels) on the growth rate, feed intake, blood and serum parameters of the animals. The animals were randomly