Petrological significance of REE in uraninite

International Nuclear Information System (INIS)

Feng Mingyue; Li Yuexiang; Xu Zhan.

1992-01-01

According to the petrological study of Zhuguangshan and Huanglongmiao granites and REE in uraninite from these granites, it can be concluded that REE contents in uraninite and granites are positively correlative; the partition characteristics of REE in uraninite are related to the acidity of initial rocks; and the fractionation degree of REE in uraninite reflects the differentiation degree of initial rocks

Petrological significance of REE in uraninite

Energy Technology Data Exchange (ETDEWEB)

Mingyue, Feng; Yuexiang, Li; Zhan, Xu

1992-09-01

According to the petrological study of Zhuguangshan and Huanglongmiao granites and REE in uraninite from these granites, it can be concluded that REE contents in uraninite and granites are positively correlative; the partition characteristics of REE in uraninite are related to the acidity of initial rocks; and the fractionation degree of REE in uraninite reflects the differentiation degree of initial rocks.

Mineralogy, geochemistry and origin of Zafarabad iron deposit based on REE and trace elements of magnetite

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Mehrdad Barati

2013-10-01

Full Text Available Zafarabad iron deposit is located northwest of Divandareh, in the northern margin of Sanandaj-Sirjan plutonic-metamorphic zone. The deposit is in lentoid to tubular shape, within a shear zone and occrrued in host rocks of calc-schist and limestone. Magnetite with massive, cataclastic and replacement textures are the main phases, while pyrite and other sulfide minerals are found. Major and trace elements are measured by ICP-MS and ICP-AES methods. Based on some ratios of trace elements in the ore samples and (Ti+V vs. Cal+Al+Mn and Ti+V vs. Ni/(Cr+Mn diagrams which are used for classification of iron deposit types, Zafarabad iron deposit fall in the range of skarn deposits. Spider diagrams show a steady decline from LREE to HREE elements with Eu (mean value of 0.06 ppm and Ce (mean value of 0.94 ppm negative anomalies. Comparing the distribution patterns of REE for the Zafarabad magnetites with those of various types of iron deposits shows that the REE pattern for Zafarabad is similar to these deposits. Analysis of calculated parameters for REE shows that the hydrothermal fluids responsible for mineralization are mainly of magmatic origin through fractionation and crystallization processes of a deep iron rich fluid phase and its emplacement within the carbonate rocks, forming iron skarn.

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

Science.gov (United States)

Protano, G; Riccobono, F

2002-01-01

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

Towards the challenging REE exploration in Indonesia

Science.gov (United States)

Setiawan, Iwan

2018-02-01

Rare earth elements (REE) are the seventeen elements, including fifteen from 57La to 71Lu, in addition to 21Sc and 39Y. In rock-forming minerals, rare earth elements typically occur in compounds as trivalent cations in carbonates, oxides, phosphates, and silicates. The REE occur in a wide range of rock types: igneous, sedimentary and metamorphic rocks. REE are one of the critical metals in the world. Their occurrences are important to supply the world needs on high technology materials. Indonesia has a lot of potential sources of REE that are mainly from residual tin mining processes in Bangka islands, which are associated with radioactive minerals e.g. monazite and xenotime. However, the REE from monazite and xenotime are difficult to extract and contain high radioactivity. Granitoids are widely distributed in Sumatra, Sulawesi, Kalimantan and Papua. They also have a very thick weathering crusts. Important REE-bearing minerals are allanite and titanite. Their low susceptibilities during weathering result an economically potential REE concentration. I-/A- type granitoids and their weathered crusts are important REE sources in Indonesia. Unfortunately, their distribution and genesis have not been deeply studied. Future REE explorations challenge are mainly of the granitoids their weathered crusts. Geochemical and mineralogical characterization of type of granitoids and their weathered crusts, the hydrothermally altered rocks, and clear REE regulation will help discover REE deposits in Indonesia.

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

Science.gov (United States)

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

2012-04-01

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

Characteristics and genesis of Rare Earth Element (REE) in western Indonesia

Science.gov (United States)

Handoko, A. D.; Sanjaya, E.

2018-02-01

Rare Earth Element (REE) has unique properties that have been used in many hightech applications. The demand of REE increased recently in the world due to its special properties. Although REE concentration in the crust is higher than gold, economically viable deposits are still rare. Reduction of REE exports by China cause increased prices of REE. Due to this condition, exploration of potential REE mines emerged. Indonesia also participates in this phenomenon, and explore the possibility of REE mines in its area. This review will discuss the characteristics and genesis of REE and its occurrence in western Indonesia; focused in Sumatera, Tin Island, and Kalimantan. The review is done based on literature research from several resources about characteristics of rare earth element in general and in the given area. The research shows that the potential REE mines can be found in several different locations in Indonesia, such as Tin Island, Sumatera, and Kalimantan. Most of them are composed of monazite, zircon, and xenotime as rare earth minerals. Monazite iss known for its elevated number of radioactive elements, so study about radioactive content and more environment friendly ore processing becomes compulsory.

Rare earth elements in sedimentary phosphate deposits: Solution to the global REE crisis?

Science.gov (United States)

Emsbo, Poul; McLaughlin, Patrick I.; Breit, George N.; du Bray, Edward A.; Koenig, Alan E.

2015-01-01

The critical role of rare earth elements (REEs), particularly heavy REEs (HREEs), in high-tech industries has created a surge in demand that is quickly outstripping known global supply and has triggered a worldwide scramble to discover new sources. The chemical analysis of 23 sedimentary phosphate deposits (phosphorites) in the United States demonstrates that they are significantly enriched in REEs. Leaching experiments using dilute H2SO4 and HCl, extracted nearly 100% of their total REE content and show that the extraction of REEs from phosphorites is not subject to the many technological and environmental challenges that vex the exploitation of many identified REE deposits. Our data suggest that phosphate rock currently mined in the United States has the potential to produce a significant proportion of the world's REE demand as a byproduct. Importantly, the size and concentration of HREEs in some unmined phosphorites dwarf the world's richest REE deposits. Secular variation in phosphate REE contents identifies geologic time periods favorable for the formation of currently unrecognized high-REE phosphates. The extraordinary endowment, combined with the ease of REE extraction, indicates that such phosphorites might be considered as a primary source of REEs with the potential to resolve the global REE (particularly for HREE) supply shortage.

Study on REE bound water-soluble polysaccharides in plant

International Nuclear Information System (INIS)

Wang Yuqi; Guo Fanqing; Xu Lei; Chen Hongmin; Sun Jingxin; Cao Guoyin

1999-01-01

The binding of REE with water-soluble polysaccharides (PSs) in leaves of fern Dicranopteris Dichotoma (DD) has been studied by molecular activation analysis. The cold-water-soluble and hot-water-soluble PSs in leaves of DD were obtained by using biochemical separation techniques. The PSs of non-deproteinization and deproteinization, were separated on Sephadex G-200 gel permeation chromatography. The absorption curves of elution for the PSs were obtained by colorimetry, and the proteins were detected using Coomassic brilliant G-250. Eight REEs (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in these PSs were determined by instrumental neutron activation analysis. The results obtained show that the REEs are bound firmly with the water-soluble PSs in the plant. A measurement demonstrates that the PSs bound with REEs are mainly of smaller molecular weight (10,000 to 20,000 Dalton)

Geochemistry of REE in Acid Mine Drainage: Sorption onto Basaluminite and Schwertmannite.

Science.gov (United States)

Lozano Letellier, A.; Ayora, C.; Fernandez-Martinez, A.

2017-12-01

The geochemistry of Rare Earth Elements (REE) has been investigated in natural streams and in mine areas during the last decades. Most of these studies agree that REE are mobile in acidic waters and they transferred to a solid phase when pH increases. However, there is no agreement on the pH range, on which precipitates can retain REE and the mechanisms responsible for the retention. Thus, whereas some authors determined that hydrous ferric oxides (HFOs) scavenge REE from pH 3, other authors observed REE retention by hydrous aluminum oxides (HAOs) from pH 4 to 6.1. A field survey conducted in the Odiel River in the SW Spain showed that pH values higher than 5, REE, Cu, Al and Fe concentrations in the river were lower than expected from a theoretical mixture because they were trapped in the precipitates. For pH below 4, however, only schwertmannite (Fe8O8OH6SO4) and no basaluminite (Al4SO4OH10·5H2O) precipitated. Then, REE, Cu and Al behaved conservatively and Fe does not, indicating that REE are trapped in the Al but not in the Fe solid phase. These observations are perfectly consistent with the REE accumulation in the Al-rich precipitates in the AMD treatment systems. Taking into account these observations, sorption experiments with synthetic basaluminite and schwertmannite at different pH were performed in the laboratory. For Lanthanides and Yttrium, sorption edge took place at pH higher than 5, whereas Sc sorption started at pH 4. A surface complexation model is proposed to explain the retention mechanism onto these two precipitates. Both minerals, schwertmannite and basaluminite showed similar sorption behavior. However, as schwertmannite formation occurs at pH lower than 4, no REE elements are sorbed on it.

Nature of parent rocks, mineralization styles and ore genesis of regolith-hosted REE deposits in South China: An integrated genetic model

Science.gov (United States)

Li, Yan Hei Martin; Zhao, Wen Winston; Zhou, Mei-Fu

2017-10-01

Regolith-hosted rare earth element (REE) deposits, also called ion-adsorption or weathered crust elution-deposited REE deposits are distributed over Jiangxi, Guangdong, Fujian, Hunan, Guangxi and Yunnan provinces in South China. In general, these deposits can be categorized into the HREE-dominated type, for example the famous Zudong deposit in southern Jiangxi province and the LREE-dominated type, such as the Heling and Dingnan deposits in southern Jiangxi province. Most of these deposits form from weathering of biotite and muscovite granites, syenites, monzogranites, granodiorites, granite porphyries, and rhyolitic tuffs. The parent rocks are generally peraluminous, siliceous, alkaline and contain a variety of REE-bearing minerals. Mostly, REE patterns of regolith are inherited from the parent rocks, and therefore, characteristics of the parent rocks impose a significant control on the ore formation. Data compilation shows that autometasomatism during the latest stage of granite crystallization is likely essential in forming the HREE-enriched granites, whereas LREE-enriched granites could form through magmatic differentiation. These deposits are normally two- to three-fold, but could be up to ten-fold enrichment in REE compared to the parent granites, where the maximum enrichment usually occurs from the lower B to the upper C horizon. Ce shows different behavior with the other REEs. Strongly positive Ce anomalies commonly occur at the upper part of weathering profiles, likely due to oxidation of Ce3+ to Ce4+ and removal of Ce from soil solutions through precipitation of cerianite. Vertical pH and redox gradients in weathering crusts facilitate dissolution of REE-bearing minerals at shallow level and fixation of REE at depth through either adsorption on clay minerals or precipitation of secondary minerals. At the same time, mass removal of major elements plays an important role in concentrating REE in regolith. Combination of mass removal and eluviation

Mineralogy and REE geochemistry at Gomish-Tappeh Zn-Pb-Cu (Ag deposit, southwest of Zanjan

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Tooba Salehi

2010-11-01

Full Text Available Gomish-Tappeh Zn-Pb-Cu (Ag deposit is located 90 km southwest of Zanjan, in northwestern part of Urumieh-Dokhtar volcano-plutonic zone. Exposed rocks at the area include Oligo-Miocene volcano-sedimentary and sedimentary sequences as well as Pliocene volcano-plutonic sequence (andesite porphyry dykes, dacitic subvolcanic dome and rhyodacitic volcanics. Alteration in the deposit developed as silicic, silicic-sulfidic, sericitic, carbonate, argillic and propylitic. Main mineralization at the Gomish-Tappeh deposit is observed as veins occurring in a steeply-deeping normal fault defined by an NE-SW trend in host rocks such as dacitic crystal litic tuff, dacitic subvolcanic dome, specifically the rhyolitic tuff. Paragenetic minerals in the ore veins consist of pyrite, arsenopyrite, chalcopyrite, bornite, low-Fe sphalerite, galena, tetrahedrite and specularite. Gangue minerals accompanying the ores include quartz, calcite, chlorite, sericite and clay minerals. Based on geochemical data, average grades for samples from the ore veins at the Gomish-Tappeh deposit are: 4% Pb, 6% Zn, 2% Cu and 88 ppm Ag. Moreover, REE distribution patterns for altered samples of the dacitic subvolcanic dome and acidic tuff when compared with fresh samples, show enrichment in LREE, while HREE demonstrate various bahaviours. The negative Eu anomaly in chondrite-normalized REE patterns for these rocks is related to the increase in fluid/rock ratio and destruction of those grains of plagioclase enriched in Eu. REE distribution patterns for the silty tuff (footwall to the ore compared with acidic tuff represent enrichment in all REE as well as positive Eu anomalies. However, the ore samples indicate more enrichment in LREE/HREE ratios and higher Eu contents when compared with wallrock of the ore veins (silty tuff. This is due to the influence of chloric magmatic-hydrothermal fluids that caused alteration along the ore zone, releasing LREE and Eu from the host rocks and finally

Geochemical pattern of rare-earth elements from ore deposits of Sete Barras and Volta Grande-PR

International Nuclear Information System (INIS)

Ronchi, L.H.; Dardenne, M.A.

1987-01-01

The fluorite ore deposits of Volta Grande and Sete Barras in Parana show similar REE distribution patterns. Fluorite ores from other regions in Parana e Santa Catarina show marked differences in the REE pattern which suggest different modes of origin. (author) [pt

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

International Nuclear Information System (INIS)

Livingston, D.

1993-07-01

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

Aeromagnetic expression of rare earth element (REE) deposits in New Mexico, USA

Science.gov (United States)

Li, M.

2016-12-01

With the development of high-tech devices and the expanding demands in industrial production, rare earth elements(REE) has been playing an increasingly important role in the global economy in the past several decades. Different types of REE serve irreplaceable functions in high-tech industry, as well as for developing sustainable energy and catalysis of manufacturing. Given that the global supply of REE has become strained since 2009 and no known substitutes for REE have been found, exploration for new REE deposits is imperative for economic sustainability. Ten main regions have REE deposits in New Mexico, some of which have not been exploited, while some sites such as Gallinas mountains vein deposits are in early exploration stage. Exploration for the reserves and quantization of mineral compositions of New Mexico's REE depositional districts can have economic benefits in general. In this study, high-resolution airborne magnetic and gravity data were used for studying the Gallinas mountains REE deposit. The purposes of this study are to: (1) characterize specific aeromagnetic anomaly and gravity features from the REE deposits, and (2) apply the characterized features to suggest other areas among the ten REE depositional regions for further exploration. All REE deposits in the study area are found associated with alkaline to alkali-calcic volcanic rocks. A quantitative modeling based on aeromagnetic and gravity anomaly mapping was constructed with an assumption of three units: carbonatites, alkaline volcanic intrusions and REE-concentrated minerals (barite, bastnaesite, etc.). The results of this study show that alkaline deposit is characterized by negative magnetic anomalies and carbonatite is associated with gravity anomaly and vertical gravity gradient high. The area with significantly high aeromagnetic anomaly area and also gravity anomaly high supposed to reflect REE-concentrated minerals such as bastnaesite. For further research, hyperspectral information and

The Influence of Basaltic Islands on the Oceanic REE Distribution: A Case Study From the Tropical South Pacific

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Mario Molina-Kescher

2018-03-01

Full Text Available The Rare Earth Elements (REEs have been widely used to investigate marine biogeochemical processes as well as the sources and mixing of water masses. However, there are still important uncertainties about the global aqueous REE cycle with respect to the contributions of highly reactive basaltic minerals originating from volcanic islands and the role of Submarine Groundwater Discharge (SGD. Here we present dissolved REE concentrations obtained from waters at the island-ocean interface (including SGD, river, lagoon and coastal waters from the island of Tahiti and from three detailed open ocean profiles on the Manihiki Plateau (including neodymium (Nd isotope compositions, which are located in ocean currents downstream of Tahiti. Tahitian fresh waters have highly variable REE concentrations that likely result from variable water–rock interaction and removal by secondary minerals. In contrast to studies on other islands, the SGD samples do not exhibit elevated REE concentrations but have distinctive REE distributions and Y/Ho ratios. The basaltic Tahitian rocks impart a REE pattern to the waters characterized by a middle REE enrichment, with a peak at europium similar to groundwaters and coastal waters of other volcanic islands in the Pacific. However, the basaltic island REE characteristics (with the exception of elevated Y/Ho ratios are lost during transport to the Manihiki Plateau within surface waters that also exhibit highly radiogenic Nd isotope signatures. Our new data demonstrate that REE concentrations are enriched in Tahitian coastal water, but without multidimensional sampling, basaltic island Nd flux estimates range over orders of magnitude from relatively small to globally significant. Antarctic Intermediate Water (AAIW loses its characteristic Nd isotopic signature (−6 to −9 around the Manihiki Plateau as a consequence of mixing with South Equatorial Pacific Intermediate Water (SEqPIW, which shows more positive values (−1 to �

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

Science.gov (United States)

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

2017-01-01

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

Homology and cohomology of Rees semigroup algebras

DEFF Research Database (Denmark)

Grønbæk, Niels; Gourdeau, Frédéric; White, Michael C.

2011-01-01

Let S by a Rees semigroup, and let 1¹(S) be its convolution semigroup algebra. Using Morita equivalence we show that bounded Hochschild homology and cohomology of l¹(S) is isomorphic to those of the underlying discrete group algebra....

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

Science.gov (United States)

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

2009-01-01

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

Rare-earth elements in granites: concentration and distribution pattern

International Nuclear Information System (INIS)

Galindo, A.C.

1983-01-01

The geochemistry of rare earth elements in granites is studied. The rare earth element (REE) distribution pattern in granites is characterized by a smooth curve with decreasing concentrations from La to Lu, and frequently a marked Eu negative anomaly. It seems to exist relationship between granite genesis and its REE pattern, in that bodies of primary (magmatic differentiation) origin always show this negative Eu anomaly, while those bodies generated by crustal anatexis do not show this anomaly. (E.G.) [pt

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

Science.gov (United States)

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

2013-04-01

reacted considerably with the liquid resulting in a strong REE enrichment relative to the original seawater. Increasing w/r ratios gave rise to decreasing pH of the quench fluid and enforced the enrichment of HREE in the fluid with relative depletion of LREE and no Eu-anomaly. The 'special' REE-signatures observed in Turtle Pits vent fluids at 5° S MAR could be reproduced in our experiments at a w/r ratio of 5 (pH = ~6), whereas at a w/r ratio of 1 (pH = ~7) the fluid exhibited the "typical" REE pattern with a positive Eu-anomaly. Fluids from experiments with w/r ratios ×10 (pH ~6 to ~2) showed higher HREE enrichment than observed in natural MOR vent fluids so far. Concluding, elevated REE concentrations in hydrothermal fluids exhibiting the 'special' REE pattern with relative enrichment of HREE and no Eu anomaly are indicative for leaching processes under high w/r ratios (~5-10) that might be more common in slow-spreading oceanic crust with focused hydrothermal fluid-flow along e.g., detachment faults [8]. References: [1] Koschinsky A., Garbe-Schönberg D., Sander S., Schmidt K., Gennerich H.-H., and Strauss H. (2008) Geology 36, 615-618. [2] Schmidt K., Garbe-Schönberg D., Bau M., and Koschinsky A. (2010) GCA 74, 4058-4077. [3] Douville E., Bienvenu P., Charlou J. L., Donval J. P., Fouquet Y., Appriou P., and Gamo T. (1999). GCA 63, 627-643. [4] You C.-F., Castillo P. R., Gieskes J. M., Chan L. H., and Spivak A. J. (1996) EPSL 140, 41-52. [5] Allen D. E. and Seyfried [Jr.] W. E.(2005) GCA 69, 675-683. [6] Seyfried [Jr.] W. E. and Bischoff J. L. (1977) EPSL 34, 71-77. [7] Hajash A. and Chandler G. W. (1981) Contrib Mineral Petrol 78, 240-254. [8] McCaig A.M. and Harris M. (2012) Geology 40, 367-370.

REE bound proteins in natural plant fern Dicranopteris dichitoma by MAA

International Nuclear Information System (INIS)

Guo, F.Q.; Wang, Y.Q.; Sun, J.X.; Chen, H.M.

1996-01-01

Biochemical techniques, including pH variation, outsalting, ultracentrifugation, gel filtration chromatography and electrophoresis, etc., have been employed together with instrumental neutron activation analysis (INAA) to study the rare earth elements (REE) bound proteins in the natural plant fern, Dicranopteris dichitoma. INAA was also used to identify whether the proteins were bound firmly with REE. The results obtained show that two REE bound proteins (RBP-I and RBP-II) have been separated. The molecular weight of RBP-I on Sephadex G-200 gel column is about 8 x 10 5 Daltons and that of RBP-II is less than 12,400 Daltons, respectively. However, SDS-PAGE of the two proteins shows that they mainly have two protein subunits with MW 14,100 and 38,700 Daltons. They are probably conjugated proteins, glycoproteins with different glyco-units. (author). 22 refs., 7 figs., 1 tab

The giant Bayan Obo REE-Nb-Fe deposit, China: Controversy and ore genesis

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Hong-Rui Fan

2016-05-01

Full Text Available Bayan Obo ore deposit is the largest rare-earth element (REE resource, and the second largest niobium (Nb resource in the world. Due to the complicated element/mineral compositions and involving several geological events, the REE enrichment mechanism and genesis of this giant deposit still remains intense debated. The deposit is hosted in the massive dolomite, and nearly one hundred carbonatite dykes occur in the vicinity of the deposit. The carbonatite dykes can be divided into three types from early to late: dolomite, co-existing dolomite-calcite and calcite type, corresponding to different evolutionary stages of carbonatite magmatism based on the REE and trace element data. The latter always has higher REE content. The origin of the ore-hosting dolomite at Bayan Obo has been addressed in various models, ranging from a normal sedimentary carbonate rocks to volcano-sedimentary sequence, and a large carbonatitic intrusion. More geochemical evidences show that the coarse-grained dolomite represents a Mesoproterozoic carbonatite pluton and the fine-grained dolomite resulted from the extensive REE mineralization and modification of the coarse-grained variety. The ore bodies, distributed along an E–W striking belt, occur as large lenses and underwent more intense fluoritization and fenitization. The first episode mineralization is characterized by disseminated mineralization in the dolomite. The second or main-episode is banded and/or massive mineralization, cut by the third episode consisting of aegirine-rich veins. Various dating methods gave different mineralization ages at Bayan Obo, resulting in long and hot debates. Compilation of available data suggests that the mineralization is rather variable with two peaks at ∼1400 and 440 Ma. The early mineralization peak closes in time to the intrusion of the carbonatite dykes. A significant thermal event at ca. 440 Ma resulted in the formation of late-stage veins with coarse crystals of REE

Geochemical and rare earth elements distribution pattern in gaiman F M.phosphatic levels, Chubu t, Argentina

International Nuclear Information System (INIS)

Castro, L.; Fazio, A.; Tourn, S.; Scasso, R.

2004-01-01

Phosphatic concretions in the Early Miocene marine sediments of the Gaiman Formation (Miocene) were analyzed for rare earth elements (REE), in order to discuss their pattern in the context of paleoenvironmental interpretations. P2O5 in concretions is between 15,61 to 21,82%. Two types of concretions are found: Type 1 represented by in situ ones developed within transgressive-early highstand system tracts which shows little evidence for significant transportation, and Type 2 related to reworking, winnowing and mechanical concentration of resistant particles. Type 1 exhibits higher REE/P ratios and a significant enrichment in HREE than Type 2. The REE pattern in both shows a slight depletion in LREE with a weak Ce anomaly (-0.08 to 0.04), and an enrichment in high rare earth elements, in comparison to the a verage shale. Their mean content in REE (915 ppm) and Y (500 ppm) doubles the worldwide phosphorite average (462 ppm and 275 ppm). No significant correlation is found between REEs and P2O5. On the other hand, HREE enrichment (Lu/Ce) increases with the REEs bulk content. The pattern is consistent with shallow water inner shelf marine environment which is also suggested by sedimentological and paleontological evidence [es

Study on REE bound proteins in natural plant fern dicranopteris dichotomy by MAA

International Nuclear Information System (INIS)

Guo Fanqing; Wang Yuqi; Sun Jingxing; Chen Hongmin; Xu Lei; Cao Guoyin

1997-01-01

Biochemical techniques, including pH variation, outsalting, ultracentrifugation, gel filtration chromatography and electrophoresis, etc., have been employed together with instrumental neutron activation analysis (INAA) to study the rare earth elements (REE) bound proteins in the natural plant fern, Dicranopteris dichotomy. INAA was also used to identify whether the proteins were bound firmly with REE. The results obtained show that two REE bound proteins (RBP-I and RBP-II) have been separated. The molecular mass (molecular weight, MW) of RBP-I on Sephadex G-200 gel column is about 8 x 10 5 and that of RBP-II is less than 12400, respectively. However, SDS-PAGE of the two proteins shows that they mainly have two protein subunits with MW 14100 and 38700. They are probably conjugated proteins, glycoproteins with different glycol-units

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

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

2016-03-01

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

Rare earth element patterns in nigerian coals

International Nuclear Information System (INIS)

Ewa, I.O.B.; Elegba, S.B.

1996-01-01

Rare Earth Elements (REE's) retain group coherence in their environment and are therefore useful geochemical markers. We report the pattern of ten REE's (La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Yb, Lu) determined by Instrumental Neutron Activation Analysis (INAA) for coals obtained from eight mines in Nigeria, namely, Okaba, Enugu, Ogbete, Onyeama, Gombe, Lafia, Asaba and Afikpo. Our results show the existence of fractionations with the highest index of 13.19 for Lafia coal, depletion in HREE, negative Eu anomaly for most of the coals, REE patterns that are consistent with chondritic trends; prominent (Eu/Eu * ) cn for Okaba and Gombe coals. Variations in geochemical data observed could suggest strong departures from band metamorphism during the coalification events of the Benue Trough geosynclines, where the coal deposits are all located. (author) 14 refs., 2 figs., 3 tabs

Trace element mobility in mine waters from granitic pegmatite U–Th–REE deposits, Bancroft area, Ontario

International Nuclear Information System (INIS)

Desbarats, A.J.; Percival, J.B.; Venance, K.E.

2016-01-01

Small, low-grade, granitic pegmatite U–Th–REE deposits are found throughout the Grenville geological province of eastern Canada. Groundwater quality at historical mining properties in the Bancroft area was investigated in order to better understand the mobility of trace elements that may pose health risks if there is renewed development of this class of mineral deposit. Groundwater samples were obtained from diamond drill holes, flowing adits and flooded mine shafts. Uranium occurs almost entirely in the dissolved (<0.45 μm) phase and is found at concentrations reaching 2579 μg/L. The Canadian maximum acceptable concentration for U in drinking water (0.02 mg/L) was exceeded in 70% of samples. Regulatory limits for 226 Ra (0.5 Bq/L) and for 210 Pb (0.2 Bq/L) were generally exceeded in these samples as well. Speciation modeling indicates that over 98% of dissolved U is in the form of highly mobile uranyl-Ca–carbonate complexes known to inhibit U adsorption. Uranium concentrations in groundwater appear to be correlated with the uranothorite content of the deposits rather than with their U grade. Uranothorite may be more soluble than uraninite, the other ore mineral, because of its non-ideal composition and metamict structure. Thorium, released concomitantly with U during the dissolution of uranothorite and thorian uraninite, exhibits median and maximum total concentrations of only 0.1 and 11 μg/L, respectively. Mass balance and stoichiometric considerations indicate that almost all Th is immobilized very close to its source. The sums of total light REE (La–Gd) concentrations have median and maximum values of 6 and 117 μg/L, respectively. The sums of total heavy REE (Tb–Lu) concentrations have median and maximum values of 0.8 and 21 μg/L, respectively. Light REE are derived mainly from the dissolution of metamict allanite whereas the sources of heavy REE are widely dispersed among accessory minerals. Fractionation patterns of REE in the dissolved

miREE: miRNA recognition elements ensemble

Science.gov (United States)

2011-01-01

Background Computational methods for microRNA target prediction are a fundamental step to understand the miRNA role in gene regulation, a key process in molecular biology. In this paper we present miREE, a novel microRNA target prediction tool. miREE is an ensemble of two parts entailing complementary but integrated roles in the prediction. The Ab-Initio module leverages upon a genetic algorithmic approach to generate a set of candidate sites on the basis of their microRNA-mRNA duplex stability properties. Then, a Support Vector Machine (SVM) learning module evaluates the impact of microRNA recognition elements on the target gene. As a result the prediction takes into account information regarding both miRNA-target structural stability and accessibility. Results The proposed method significantly improves the state-of-the-art prediction tools in terms of accuracy with a better balance between specificity and sensitivity, as demonstrated by the experiments conducted on several large datasets across different species. miREE achieves this result by tackling two of the main challenges of current prediction tools: (1) The reduced number of false positives for the Ab-Initio part thanks to the integration of a machine learning module (2) the specificity of the machine learning part, obtained through an innovative technique for rich and representative negative records generation. The validation was conducted on experimental datasets where the miRNA:mRNA interactions had been obtained through (1) direct validation where even the binding site is provided, or through (2) indirect validation, based on gene expression variations obtained from high-throughput experiments where the specific interaction is not validated in detail and consequently the specific binding site is not provided. Conclusions The coupling of two parts: a sensitive Ab-Initio module and a selective machine learning part capable of recognizing the false positives, leads to an improved balance between

Novel matrix for REEs recovery from waste disposal

International Nuclear Information System (INIS)

Hareendran, K.; Singha, Mousumi; Roy, S.B.; Pal, Sangita

2014-01-01

Sorption of lanthanides (98%-99%) onto a novel matrix (polyacrylamide-carboxylate hydroxamate-PAMCHO) not only remove REE's before effluent disposal but also reduces the chance of contamination of potable water, nuclear plant generated shut down or gadolinium containing effluent during controlled fission reaction, in pharmaceutical diagnosis (MRI) and many other useful process effluents. By using such sorbent, 88% of the lanthanides can be recovered using HCl solution less than pH 1 from the laden matrix and can be concentrated more than 5 times. However, sorption into the interlayer's and diffusion of the REE's during leaching depends on the cross-linked structure of the gel matrix and tortuous path of the porous micro-channel (using scanning electron microscope-SEM study). The sequestration of matrix with REE's has been well established by using instrument FT-IR and gadolinium (cation-lanthanide) exchange method. To understand interaction of REE with sorbent, matrix have been prepared with cross-linking amount variation, such as 85:15, 90:10, 95:05 and 98:02 (matrix: cross-linker). A detailed sorption study of cross-linked matrix with gadolinium in feed solution (184 ppm), filtrate, leached and laden sorbent establishes mass balance (using ICP-AES for quantitative determination). This optimized sorbent (PAMCHO) indicates recovery of valuable REEs with elution factor of more than 0.9 when HCl solution of pH1.5 was used. (author)

Examination of rare earth element concentration patterns in freshwater fish tissues.

Science.gov (United States)

Mayfield, David B; Fairbrother, Anne

2015-02-01

Rare earth elements (REEs or lanthanides) were measured in ten freshwater fish species from a reservoir in Washington State (United States). The REE distribution patterns were examined within fillet and whole body tissues for three size classes. Total concentrations (ΣREE) ranged from 0.014 to 3.0 mg kg(-1) (dry weight) and averaged 0.243 mg kg(-1) (dry weight). Tissue concentration patterns indicated that REEs accumulated to a greater extent in organs, viscera, and bone compared to muscle (fillet) tissues. Benthic feeding species (exposed to sediments) exhibited greater concentrations of REEs than pelagic omnivorous or piscivorous fish species. Decreasing REE concentrations were found with increasing age, total length or weight for largescale and longnose suckers, smallmouth bass, and walleye. Concentration patterns in this system were consistent with natural conditions without anthropogenic sources of REEs. These data provide additional reference information with regard to the fate and transport of REEs in freshwater fish tissues in a large aquatic system. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rare earth element patterns in biotite, muscovite and tourmaline minerals

International Nuclear Information System (INIS)

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

1986-01-01

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

Modification of REE distribution of ordinary chondrites from Atacama (Chile) and Lut (Iran) hot deserts: Insights into the chemical weathering of meteorites

Science.gov (United States)

Pourkhorsandi, Hamed; D'Orazio, Massimo; Rochette, Pierre; Valenzuela, Millarca; Gattacceca, Jérôme; Mirnejad, Hassan; Sutter, Brad; Hutzler, Aurore; Aboulahris, Maria

2017-09-01

The behavior of rare earth elements (REEs) during hot desert weathering of meteorites is investigated. Ordinary chondrites (OCs) from Atacama (Chile) and Lut (Iran) deserts show different variations in REE composition during this process. Inductively coupled plasma-mass spectrometry (ICP-MS) data reveal that hot desert OCs tend to show elevated light REE concentrations, relative to OC falls. Chondrites from Atacama are by far the most enriched in REEs and this enrichment is not necessarily related to their degree of weathering. Positive Ce anomaly of fresh chondrites from Atacama and the successive formation of a negative Ce anomaly with the addition of trivalent REEs are similar to the process reported from Antarctic eucrites. In addition to REEs, Sr and Ba also show different concentrations when comparing OCs from different hot deserts. The stability of Atacama surfaces and the associated old terrestrial ages of meteorites from this region give the samples the necessary time to interact with the terrestrial environment and to be chemically modified. Higher REE contents and LREE-enriched composition are evidence of contamination by terrestrial soil. Despite their low degrees of weathering, special care must be taken into account while working on the REE composition of Atacama meteorites for cosmochemistry applications. In contrast, chondrites from the Lut desert show lower degrees of REE modification, despite significant weathering signed by Sr content. This is explained by the relatively rapid weathering rate of the meteorites occurring in the Lut desert, which hampers the penetration of terrestrial material by forming voluminous Fe oxide/oxyhydroxides shortly after the meteorite fall.

The recovery of rare earth elements (REE) from beach sands

International Nuclear Information System (INIS)

Petrache, Cristina A.; Santos, Gabriel P. Jr.; Fernandez, Lourdes G.; Castillo, Marilyn K.; Tabora, Estrellita U; Intoy, Socorro P.; Reyes, Rolando Y.

2005-01-01

This preliminary study describes a metallurgical process that will extract, recover and produce REE oxides from beach sands obtained from Ombo, San Vicente, northern Palawan. The beach sands contain REE minerals of allanite and small amounts of monazite. Allanite is a sorosilicate mineral containing rare earths, thorium and uranium. Monazite is the anhydrous phosphate of cerium and the lanthanum group of rare earths with thorium commonly present in replacement for cerium and lanthanum. Collected beach sand were first pan-concentrated in-situ to produce heavy mineral concentrates. Screening using a 32 mesh (0.500 mm) sieve was done at the Nuclear Materials Research Laboratory to remove oversize sand particles. The -32 mesh fraction was treated with bromoform (sp. gr. 2.89) to separate the heavy minerals from siliceous gangue. Grinding to -325 mesh size (0.044mm) followed to liberate the minerals prior to leaching. Two acids leachants were used - concentrated HCl for the first trial and a mixture of concentrated HCl and HNO 3 (10:1 volume ratio) for the second trial. Both leaching trials were carried out at 180 o C for 7 hours or until dry. The resulting leached residues were re-dissolved in concentrated HCl and filtered. Ionquest R 801, an organophosphorous extractant, was added to the filtrate to separate the radioactive thorium from REE. Sodium hydroxide was added to the aqueous phase to precipitate the REE. After filtering the precipitate, it was dissolved in HCl. The acid solution was repeatedly extracted three (3) times with Ionquest R 801 to remove iron and other contaminants. Ammonium hydroxide was added to the final solution to precipitate the REE, which was then dried in the oven. The precipitate was calcined/roasted in the furnace at two different temperatures for different periods of time to burn off the organic matter and to form oxides. Results of the XRD analysis showed peaks of the calcined precipitate matching with the peaks of lanthanum oxide

Determination of REE in urban park soils from Sao Paulo city for fingerprint of traffic emission contamination

International Nuclear Information System (INIS)

Figueiredo, Ana Maria G.; Camargo, Sonia P.; Sigolo, Joel B.

2009-01-01

The study of rare earth elements (REE) distribution in urban environments has become very interesting in the last years, due to the increasing industrial use of these elements. The REE La, Ce and Nd are used in automobile converter catalysts to stabilize the catalyst support and to enhance the oxidation of pollutants. The honeycomb structure has a typical association of a high Ce (and often also La) concentration combined with high concentrations of Platinum Group Elements. Due to thermal and mechanical wear of catalysts, fine particles enriched in REE are released to the environment. These catalyst particles can accumulate in urban soils, mainly in soils located near high density traffic roads. The aim of this paper was to study the REE distribution and ratios in surface soil samples collected in fourteen urban public parks of Sao Paulo city, to assess the influence of vehicular emissions. Instrumental Neutron Activation Analysis (INAA) was used for the REE analysis. The diagrams normalized to chondrite values showed an enrichment of the light REE (La to Sm), in contrast to the heavy REE (Eu to Lu), with a negative anomaly of Eu. The results obtained indicated that the enrichment in REE is not clearly attributed to vehicular traffic, because of high background values associated to the natural geological composition of the soils. (author)

Novel approach in k0-NAA for highly concentrated REE Samples.

Science.gov (United States)

Abdollahi Neisiani, M; Latifi, M; Chaouki, J; Chilian, C

2018-04-01

The present paper presents a new approach for k 0 -NAA for accurate quantification with short turnaround analysis times for rare earth elements (REEs) in high content mineral matrices. REE k 0 and Q 0 values, spectral interferences and nuclear interferences were experimentally evaluated and improved with Alfa Aesar Specpure Plasma Standard 1000mgkg -1 mono-rare earth solutions. The new iterative gamma-ray self-attenuation and neutron self-shielding methods were investigated with powder standards prepared from 100mg of 99.9% Alfa Aesar mono rare earth oxide diluted with silica oxide. The overall performance of the new k 0 -NAA method for REEs was validated using a certified reference material (CRM) from Canadian Certified Reference Materials Project (REE-2) with REE content ranging from 7.2mgkg -1 for Yb to 9610mgkg -1 for Ce. The REE concentration was determined with uncertainty below 7% (at 95% confidence level) and proved good consistency with the CRM certified concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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.

REE interactions with hydroxyapatite. Formation of secondary solid phases

International Nuclear Information System (INIS)

Seco, F.; Pablo, J. de; Bruno, J.

2005-01-01

Full text of publication follows: Lighter rare earth elements (REE) commonly occur in nature as the phosphate mineral monazite, while the heavier REE and Yttrium occur as the phosphate mineral xenotime, which has a similar composition, but different coordination environment of the cation. The geochemical behaviour of REE is mainly controlled by their interactions with phosphate minerals such as hydroxyapatite, Ca 5 (PO 4 ) 3 OH, which is a very common phosphate phase in subsurface environments. Furthermore, is a material considered to be used in a High Level Nuclear Waste repository due to its high capacity in the retention of radionuclides. The objective of this work has been to study the reaction mechanisms and thermodynamics of the interaction of La(III) and Yb(III) with hydroxyapatite as a model for general Ln(III) and Ac(III) behaviour. The surface interaction of La(III) and Yb(III) with synthetic hydroxyapatite has been investigated in batch experiments with low REE 3+ initial concentrations in constant 0.1 M NaClO 4 , at room temperature and in N 2 (g) atmosphere to avoid carbonate complex formation. The initial kinetic experiments indicated that a short contact time is needed to reach equilibrium ( 4 .nH 2 O, where a 0.83 4 .nH 2 O with 1.78 4 medium and under N 2 (g) atmosphere. The experimental data indicate that the solubility equilibria is mainly controlled by the aqueous species REE 3+ until approximately pH=5 where the formation of aqueous complexes of the form REEHPO 4 + , REEPO 4 and REE(PO 4 ) 2 3- must be considered. (authors)

REE Comparison Between Muncung Granite Samples and their Weathering Products, Lingga Regency, Riau Islands

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Ronaldo Irzon

2016-11-01

Full Text Available DOI:10.17014/ijog.3.3.149-161The increasing demand for Rare Earth Elements (REE is related to the continous development of technology, and these elements are used in modern equipments. REE can occur in igneous and sedimentary rocks in significant amounts as primary deposits, whereas the secondary REE deposit can be produced by intensive lateritic weathering of bedrocks under the tropical or subtropical climate. Lateritic process can increase REE concentration from sub-economic levels in host rocks to be more valuable. Muncung Granite is located in a tropical area of Lingga Regency, Riau Islands Province. REE occurs in the Muncung Granite and in weathered layers (saprolite, laterite, and soil. ICP-MS was applied to measure the REE content in all samples of this study. The average REE content of the Muncung Granite is 265 ppm with Eu anomaly in REE’s spider diagrams. Lateritization process has increased REE content by more than four times compared to that in the Muncung Granite. Ce and Eu anomalies in weathered layers can be associated with weathering process and initial REE contents in the host rock. Ce anomaly in a laterite layer is found to have a negative correlation to REE total enrichment. The REE level in the Muncung Granite is higher than the content in the soil and saprolite layers, but lower than that in the laterite.

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

Science.gov (United States)

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

2012-12-01

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

Petrography and Geochemistry (Trace, Ree and Pge of Pedda Cherlo Palle Gabbro-Diorite Pluton, Prakasam Igneous Province, Andhra Pradesh, India

Directory of Open Access Journals (Sweden)

Subramanyam K.S.V.

2015-09-01

Full Text Available Prakasam Igneous Province (PIP is an important geological domain in the Eastern Dharwar Craton (EDC, found in the junction zone between the EDC and Eastern Ghat Mobile Belt (EGMB. The Pedda Cherlo Palle (PCP gabbros are massive, leucocratic-mesocractic, and show cumulus textures with minerals plagioclase, cpx, and amphiboles. Compositionally, plagioclase is a labradorite-bytownite, cpx is diopside to augite, olivines are hyalosiderites and amphiboles are magnesiohornblendes. PCP gabbros have normal SiO2, high Al2O3, moderate to high TiO2, Na2O and medium Fe2O3, so, classified as subalkaline tholeiitic gabbros. Fractionated rare earth element (REE patterns, high abundance of large ion lithofile elements (LILE and transitional metals coupled with light REE (LREE relative enrichment over heavy REE (HREE and Nb are characteristics of partial melting of depleted mantle and melts that have undergone fractional crystalisation. These partial melts are enriched in LREE and LILE, due to the addition of slab derived sediment and fluids. PCP gabbros contain low abundance (5.1 to 24.6 ng/g of platinum group elements (PGE, and show an increase in the order Ir>Os>Pt>Ru»Pd>Rh. We propose that the subduction related intraoceanic island arc might have accreted to the southeastern margin of India to the east of Cuddapah basin in a collisional regime that took place during Ur to Rodinia amalgamations.

REE potential of the Nordkinn Peninsula, North Norway: A comparison of soil and bedrock composition

International Nuclear Information System (INIS)

Schilling, Julian; Reimann, Clemens; Roberts, David

2014-01-01

Highlights: • Soil geochemistry outlines an extensive REE anomaly on the Nordkinn Peninsula, North Norway. • Soil and bedrock geochemistry are compared with respect to REE and other HFSE. • Petrology of soil and rock samples reveals that the economic potential is limited. • Poor condition of REE minerals causes elevated REE concentrations in AR-digested soil samples. - Abstract: Regional-scale, low-density sampling, geochemical surveys using a variety of different sample materials have repeatedly indicated the Nordkinn Peninsula (northern Norway) as a substantial rare earth element (REE) anomaly. Recently, a more detailed soil geochemical survey, covering about 2000 km 2 at a sample density of 1 site per 2 km 2 , was carried out in the area. The new geochemical survey outlined a large area (several hundred km 2 ) where the soil samples contained several hundred and up to over 2000 mg/kg aqua regia extractable REE. In the surroundings of the highest soil anomalies, bedrock samples were collected for a mineralogical and compositional characterisation of the metasedimentary bedrock with focus on the possible economic potential. The REE concentrations obtained for aliquots of bedrock following aqua regia extraction, 4-Acid digestion and Li-borate fusion/decomposition closely match the results from soil pulps after an aqua regia extraction. Total contents for the REE determined in bedrock using the above methods range between 19 and 429 mg/kg, indicating an overall limited economic REE potential and the predominance of the light REE over the heavy REE. In terms of petrography, essentially all the bedrock samples are characterised by the presence of detrital, altered and locally even decomposed allanite (a LREE-incorporating, epidote-group mineral) and minor xenotime (a HREE-incorporating phosphate) while texturally stable REE phases are scarce. It is the poor condition of the REE minerals that makes them prone towards acidic leaching and, given similar results

Average sedimentary rock rare Earth element patterns and crustal evolution: Some observations and implications from the 3800 Ma ISUA supracrustal belt, West Greenland

Science.gov (United States)

Dymek, R. F.; Boak, J. L.; Gromet, L. P.

1983-01-01

Rare earth element (REE) data is given on a set of clastic metasediments from the 3800 Ma Isua Supracrustal belt, West Greenland. Each of two units from the same sedimentary sequence has a distinctive REE pattern, but the average of these rocks bears a very strong resemblance to the REE pattern for the North American Shale Composite (NASC), and departs considerably from previous estimates of REE patterns in Archaean sediments. The possibility that the source area for the Isua sediments resembled that of the NASC is regarded as highly unlikely. However, REE patterns like that in the NASC may be produced by sedimentary recycling of material yielding patterns such as are found at Isua. The results lead to the following tentative conclusions: (1) The REE patterns for Isua Seq. B MBG indicate the existence of crustal materials with fractionated REE and negative Eu anomalies at 3800 Ma, (2) The average Seq. B REE pattern resembles that of the North American Shale Composite (NASC), (3) If the Seq. B average is truly representative of its crustal sources, then this early crust could have been extensively differentiated. In this regard, a proper understanding of the NASC pattern, and its relationship to post-Archaean crustal REE reservoirs, is essential, (4) The Isua results may represent a local effect.

Rees, Prof. Lord Martin (John)

Indian Academy of Sciences (India)

Home; Fellowship. Fellow Profile. Elected: 1991 Honorary. Rees, Prof. Lord Martin (John) FRS. Date of birth: 23 June 1942. Address: Emeritus professor of Cosmology & Astrophysics, Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, U.K.. Contact: Office: (+44-1223) 33 7548

Rare earth element and strontium isotopic study of seamount-type limestones in Mesozoic accretionary complex of Southern Chichibu Terrane, central Japan. Implication for incorporation process of seawater REE into limestones

International Nuclear Information System (INIS)

Tanaka, Kazuya; Miura, Noriko; Asahara, Yoshihiro; Kawabe, Iwao

2003-01-01

Ishimaki and Tahara limestones occur as exotic blocks juxtaposed in the Mesozoic (Jurassic) accretionary complex of Southern Chichibu Terrane in eastern Aichi Prefecture, central Japan. They are supposed to be of the seamount-type limestone, since they have no terrigenous materials and are intimately associated with greenstones. REE (rare earth elements) and Sr isotopic studies for the limestones have been made in order to know their geochemical characteristics, ages and origins. Their 87 Sr/ 86 Sr ratios, when referred to the seawater 87 Sr/ 86 Sr curve and relevant geological data, suggest that Ishimaki and Tahara limestones are the late Permian and the Carboniferous to the Early Permian, respectively. Two greenstone fragments found inside the Ishimaki limestone block and one greenstone sample associated with Tahara limestone block, resemble the Hawaiian alkali basalt in the their REE and Y patterns. This is supporting the idea that the limestone blocks may be parts of reef limestones on ancient volcanic seamounts. All the limestone samples, except three unusual Tahara ones, show seawater REE and Y signatures in their chondrite-normalized patterns. Their REE/Ca ratios, however, are 10 2 -10 4 times as high as those ratios of modern biogenic carbonates like corals and the seawater. Accordingly, seawater REE and Y were incorporated into the limestones, when originally biogenic carbonates transformed into inorganic calcite and its secondary growths occurred in diagenesis in contact with sufficient seawater. This view is favored by the reported REE partition experiment between calcite overgrowths and seawater solution. The seawater Ce anomaly as a function of water depth in the modern ocean is a key to infer the water depth of the REE and Y incorporation. The Ce anomalies given by log (Ce/Ce*) for about a half of Ishimaki samples and most of Tahara ones are between -0.5 and -0.2, which are compatible with the shallow water origin. Another half of Ishimaki samples

Incorporation of REE into leucophanite

DEFF Research Database (Denmark)

Mortensen, Henrik Friis; Balic Zunic, Tonci; Williams, C.T.

2007-01-01

The crystal structures of nine, and the chemical compositions of ten, natural samples of leucophanite, ideally NaCaBeSi2O6F, were investigated. The analysed samples display a large compositional variation with trace-element abundances >50,000 ppm, primarily due to rare earth elements (REE). Fromt...

U-TH-REE mobility and diffusion in granitic environments during alteration of accessory minerals and U-ores

International Nuclear Information System (INIS)

Cathelineau, M.; Vergneaud, M.

1989-01-01

U, Th and REE concentrations and distributions have been studied in granitic rocks, using a multidisciplinary approach involving micromapping of cracks in oriented samples, together with mineralogical and geochemical studies of the different U-Th-REE bearing phases. The behavior of U, Th and Nd, considered as chemical analogue elements of the radiotoxic nuclides, was investigated either in the vicinity of microsites (accessory mineral enviornment) or along plurimetric sections around U-ore bodies. The different granite minerals, especially the accessory minerals (uraninite, monazite, thorite, apatite, xeonotime), as well as U-ores, present different initial concentrations of U, Th and REE. Limitations to the analogy between these U-Th-REE concentrations and the radwastes is discussed as a function of their mineralogical features, chemical compostion, size and solubilities. These primary concentrations present different behavior when subjected to hydrothermal alteration, such as propylitization, phyllite type alteration, or clay alteration. Results show that in reduced media, in the temperature range 80-2000 0 C, the rate of mobilization of U, Th, REE is relatively moderate. However, fluids enriched in flourides, phosphates or carbonates may significantly solubilize and transport U and REE under specific conditions. In addition, the degree of opening of the microcracks and faults, as well as the oxidation-reduction processes, are critical parameters for the efficiency of the granitic geological barrier

Distribution of REEs and yttrium among major geochemical phases of marine Fe–Mn-oxides: Comparative study between hydrogenous and hydrothermal deposits

Digital Repository Service at National Institute of Oceanography (India)

SuryaPrakash, L.; Ray, D.; Paropkari, A.L.; Mudholkar, A.V.; Satyanarayanan, M.; Sreenivas, B.; Chandrasekharam, D.; Kota, D.; KameshRaju, K.A.; Kaisary, S.; Balaram, V.; Gurav, T.

REEs. Thermodynamic calculations (Hass et al., 1995) as well as laboratory experiments (Lewis et al., 1998; Douville et al., 1999) show that dissolved REEs in geothermal fluid mostly occur as fluoride, chloride, sulfate complexes or free...

Behaviour of REEs in a tropical estuary and adjacent continental ...

Indian Academy of Sciences (India)

total organic carbon, U/Th ratio, authigenic U, Cu/Zn, V/Cr ratios revealed the oxic environment and thus the ... tions due to depletion by sorption onto particles. .... trace elements (Cr, Ni, Co, Zn) were analysed along ... Results. The concentration of REE and trace elements ..... This effect causes a split of the normalised REE.

Study of REE behaviors, fluid inclusions, and O, S stable Isotopes in Zafar-abad iron skarn deposit, NW Divandarreh, Kordestan province

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Mehrdad Barati

2014-10-01

interfinger with meta-sedimentary and fragmental wall-rock. The thickness of the ore body is 25 to 35 m with 40 m wide and around 130 m in elongate. The chondrite normalized REE distribution pattern of Zafar-abad magnetite shows V shape. The analyzed samples display similar patterns. The average (La/Ybcn ratio of 6.8 indicates a high degree of fractionation. The fractionation is more pronounced in HREE part of diagram, where the average (Gd/Ybcn ratio is 1.07, whereas the average (La/Smcn ratio in the LREE part of the diagram is only 5.9. This indicates that the REE content in Zafar-abad magnetite is not affected by hydrothermal alteration. The ΣREE content varies between 2.09 and 15.02 ppm with an average of 8.4 ppm. These REE values are equal to those reported for the type of Skarn- type iron deposits (Bowman et al., 1985. Other features include pronounced negative Eu and Ce and positive Pr and Gd anomalies. Six purified magnetite samples used for Isotope Studies and δ18O values are measured in them. The units of results are permil (‰ relative to SMOW for oxygen. The δ18O values content varies between -5.93 and -0.28 ‰ with an average of -2.26 ‰. Considering that the magnetites formed at two stages (Meinert, 1995, the first one about 370 °C, and the second one about 240°C which is a reasonable guess bearing in mind that they are associated with intrusive and extrusive granitoids, then the fluid from which they formed, would yield δ18O values that range from 4.1 to 8.1 ‰ which will fall in the boundary of magmatic water box and hence provide further support for a mixed magmatic and meteoric origins of Zafar-abad magnetite deposit. In the Zafar-abad deposit, sulfur isotope composition was studied on six pyrite samples. The δ34S values for this mineral in Zafar-abad vary from +1.2 to +1.9 ‰, with an average value of +1.61‰. Zafar-abad isotopic temperatures have been determined from the δ34S values in pyrite. This temperature range is from 204 to 350�

REE Partitioning in Lunar Minerals

Science.gov (United States)

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

2015-01-01

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

Magmatic evolution and REE mineralization in the early Cambrian Jbel Boho igneous complex in the Bou Azzer inlier (Anti-Atlas/Morocco)

OpenAIRE

Benaouda, Rachid

2015-01-01

The igneous rocks of Jbel Boho emerged in three phases: an initial phase with alkaline volcanism followed by the intrusion of a syenitic pluton and later the emplacement of a dyke swarm. The Jbel Boho alkaline complex shows some interesting aspects of hydrothermal REE mineralization in the late differentiation stage. REE mineralization is found in a rhyolitic dyke and some late hydrothermal veins. Synchysite-(Ce), which was identified by EPMA analysis, is the main REE mineral.

REE characteristics and uranium metallogenesis of sandstone-type uranium deposits in northern Sichuan

International Nuclear Information System (INIS)

Zhu Xiyang; Wang Yunliang; Wang Zhichang; Zhang Chengjiang

2004-01-01

On the basis of the analysis of a large number of samples at sandstone-type uranium deposits in northern Sichuan, this paper analyses the REE composition of country rocks, ores, calcite-veins and uranium minerals, and systematically summarizes their REE geochemical characteristics, and discusses variation regularity of REE during depositional and diagenetic processes. By comparing these characteristics with those of typical hydrothermal volcanics-type and metamorphic rock type uranium deposits both at home and abroad, authors suggest that sandstone-type uranium deposits in northern Sichuan are characterized by REE geochemical features of hydrothermal reworking metallogenesis, the uranium mineralization has experienced two stages: the diagenetic preconcentration and the concentration of hydrothermal reworking

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

Science.gov (United States)

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

2003-01-01

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

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

Science.gov (United States)

Kang, Nancy

2016-01-01

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

Microbial mobilization of rare earth elements (REE from mineral solids—A mini review

Directory of Open Access Journals (Sweden)

Fabienne Barmettler

2016-06-01

Full Text Available In the light of an expected supply shortage of rare earth elements (REE measures have to be undertaken for an efficient use in all kinds of technical, medical, and agricultural applications as well as—in particular—in REE recycling from post-use goods and waste materials. Biologically- based methods might offer an alternative and supplement to physico-chemical techniques for REE recovery and recycling. A wide variety of physiologically distinct microbial groups have the potential to be applied for REE bioleaching form solid matrices. This source is largely untapped until today. Depending of the type of organism, the technical process (including a series of influencing factors, the solid to be treated, and the target element, leaching efficiencies of 80 to 90% can be achieved. Bioleaching of REEs can help in reducing the supply risk and market dependency. Additionally, the application of bioleaching techniques for the treatment of solid wastes might contribute to the conversion towards a more sustainable and environmental friendly economy.

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

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

2013-12-01

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

Petrology and geochemistry of REE-rich Mafé banded iron formations (Bafia group, Cameroon)

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Nkoumbou, Charles; Gentry, Fuh Calistus; Tchakounte Numbem, Jacqueline; Belle Ekwe Lobé, Yolande Vanessa; Nwagoum Keyamfé, Christin Steve

2017-07-01

Archaean-Paleoproterozoic foliated amphibole-gneisses and migmatites interstratified with amphibolites, pyroxeno-amphibolites and REE-rich banded-iron formations outcrop at Mafé, Ndikinimeki area. The foliation is nearly vertical due to tight folds. Flat-lying quartz-rich mica schists and quartzites, likely of Pan-African age, partly cover the formations. Among the Mafé BIFs, the oxide BIF facies shows white layers of quartz and black layers of magnetite and accessory hematite, whereas the silicate BIF facies is made up of thin discontinuous quartz layers alternating with larger garnet (almandine-spessartine) + chamosite + ilmenite ± Fe-talc layers. REE-rich oxide BIFs compositions are close to the East Pacific Rise (EPR) hydrothermal deposit; silicate BIFs plot midway between EPR and the associated amphibolite, accounting for a contamination by volcanic materials, in addition to the hydrothermal influence during their oceanic deposition. The association of an oceanic setting with alkaline and tholeiitic magmatism is typical of the Algoma-type BIF deposit. The REE-rich BIFs indices recorded at Mafé are interpreted as resulting from an Archaean-Paleoproterozoic mineralization.

REE behavior during weathering of basaltic rocks from the Lisbon Volcanic Complex (Portugal)

International Nuclear Information System (INIS)

Prudencio, M.I.; Cabral, J.M.P.; Sequeira Braga, M.A.

1991-01-01

Two weathering profiles developed in alkali basalts from the Lisbon Volcanic Complex were chosen for a REE behavior study. Profile 1 consists of a lava flow with porphyritic texture. Olivine and clinopyroxene are set in a groundmass which mainly comprises plagioclase, clinopyroxene, olivine, biotite, glass and Fe-Ti oxides. X-ray diffraction analysis of the 0 < 2μm fraction revealed: 45-95% smectites and 5-40% halloysite (7.3 angstrom), and Fe and/or Ti oxides. Profile 2 consists of a lava flow with an intergranular texture, where olivine, clinopyroxene and spinel grains are surrounded by large feldspars laths. The 0 < 2μ fraction consists of 80-100% halloysite (7.3 angstrom), < 20% micas and < 10% palygorskite and Fe and/or Ti oxides. The REE were determined by instrumental neutron activation analysis. The clay-sized fractions of the more weathered samples were separated and analyzed too. For the whole samples it was observed that: (1) when halloysites are the dominant clay-minerals (profile 2), REE are more retained in the profile and (2) in general the light REE are less concentrated in the profiles than the intermediate or even the heavy REE. In most weathered samples of profile 1 a significant loss of Ce was found. The REE in the 0 < 2μm fractions are in general enriched relative to the whole samples. In profile 1, where smectites dominate, a significant negative Ce anomaly is also present except for one sample collected at an intermediate level. Among the REE analyzed, Nd is the most enriched compared to the whole samples. In profile 2, where halloysites dominate and micas are present mainly at the bottom of the profile, it was observed that: (a) REE are less fractionated than in profile 1, (b) Ce is depleted at the bottom of the profile but increases upwards, so that at the top the 0 < 2μm fraction reveals a small positive anomaly relative to whole sample

Deciphering human-climate interactions in an ombrotrophic peat record: REE, Nd and Pb isotope signatures of dust supplies over the last 2500 years (Misten bog, Belgium)

Science.gov (United States)

Fagel, N.; Allan, M.; Le Roux, G.; Mattielli, N.; Piotrowska, N.; Sikorski, J.

2014-06-01

A high-resolution peat record from Eastern Belgium reveals the chronology of dust deposition for the last 2500 years. REE and lithogenic elements in addition to Nd and Pb isotopes were measured in a 173 cm age-dated peat profile and provide a continuous chronology of dust source and intensity. Calculated dust flux show pronounced increases c. 300 BC, 600 AD, 1000 AD, 1200 AD and from 1700 AD, corresponding to local and regional human activities combined with climate change. The Industrial Revolution samples (1700-1950 AD) are characterised by a significant enrichment in Sc-normalised REE abundance (sum REE/Sc > 25) due to intensive coal combustion. For the pre-Industrial Revolution samples, the Sc-normalised REE abundance (10 climate. Combining REE abundance, fractionation between Light REE and Heavy REE and Nd isotope data in ombrotrophic peat allows one to distinguish between dust flux changes related to human and climate forcings.

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

Science.gov (United States)

Hissler, Christophe; Stille, Peter

2015-04-01

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

A comparison of the analysis of REE-bearing phosphates by standardless EDS and standardised EDS and WDS

International Nuclear Information System (INIS)

Griffin, B.J.; Hancock, R.C.; Trautman, R.L.

2002-01-01

Full text: Current generation energy dispersive X-ray analysis systems EDS on SEM are user-friendly with 'simple' software interfaces. Minimal training is considered necessary for operation. One aim of this study was to test this hypothesis. The second aim, as a part of other studies, was to compare the results of the x-ray microanalysis of a suite of rare earth element (REE) bearing standard glasses and also a suite of rare earth element (REE) bearing phosphate mineral grains using different analytical systems. Our results from the same sample mounts have been obtained using three analytical systems: an Oxford Instruments ISIS EDS on a JEOL 6400 SEM, a Noran Voyager EDS on a JEOL 6400 SEM and a Moran Scientific WDS package on a JEOL 6400 SEM. A total of forty nine natural mineral grains have been analysed for twenty-two elements, including the REE, Ca, P and F (where possible) by each analytical system. Additional analyses were obtained from simple REE-bearing glass standards, each containing only one REE at around 11 wt %. The natural mineral grain results obtained from the different analytical systems show a number of significant variations. The two EDS datasets are comparable in terms of total REE but generally are a factor of two less than the WDS dataset. Internally the EDS datasets differ in that one set shows consistently a strong negative yttrium oxide result (typically -1 wt %) due to an excessive correction for a strong phosphorus overlap (Ka on La) whereas the second dataset shows the reverse with typically 1 wt % yttrium oxide reported, as a result of inadequate correction of the phosphorus overlap. Major elements are comparable between the standard-based datasets but not with the standardless dataset although all show similar reproducibility. The standard glass results are more coherent and consistent, as would be expected from the simpler composition and higher abundances. One clear outcome from these data is that complex compositions where

REE compositions in fossil vertebrate dental tissues indicate biomineral preservation

Science.gov (United States)

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

2012-04-01

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

Origin of convex tetrads in rare earth element patterns of hydrothermally altered siliceous igneous rocks from the Zinnwald Sn W deposit, Germany

Science.gov (United States)

Monecke, T.; Dulski, P.; Kempe, U.

2007-01-01

The chondrite-normalized rare earth element (REE) patterns of whole rock samples from evolved granitic systems hosting rare metal deposits sometimes show a split into four consecutive curved segments, referred to as tetrads. In the present contribution, a rigorous statistical method is proposed that can be used to test whether geological significance should be attributed to tetrads that are only of limited size. The method involves a detailed evaluation of element and sample specific random and systematic errors that are constrained on the basis of independent repeated preparations and analyses of sample and reference materials. Application of the proposed method to samples from the granite-hosted Zinnwald Sn-W deposit, Germany, revealed that at least two tetrads in normalized whole rock REE patterns have to be analytically significant to rule out that fractional crystallization led to the unusual behavior of the REEs. Based on the analysis of altered albite granite and greisen samples from the endocontact of the Zinnwald granite massif, it is demonstrated that the lanthanide tetrad effect is responsible for the formation of the convex tetrads. Geological and petrological evidence suggests that the tetrads in the samples developed prior to greisenization and related cassiterite precipitation. In contrast to the endocontact samples, the rhyolitic wall rocks are typified by normalized REE patterns having tetrads that are variable in size and frequently close to the limit of analytical significance. The sizes of the tetrads apparently correlate with the intensity of albitization, but show no relation to subsequent alteration processes including greisenization and low-temperature argillization. This observation proves that curved segments in normalized whole rock REE patterns can be introduced during hydrothermal fluid-rock interaction.

Determination of the REE in environmental samples near a coal power station based on k0-standardized NAA with counting in a LEPD

International Nuclear Information System (INIS)

Freitas, M.C.; Gouveia, M.A.; Prudencio, M.I.; Cabral, J.M.P.; Corte, F. de

1993-01-01

The REE contents in lichens and plants determined by k 0 -standardized NAA with LEPD and HPGe are compared. Similar values were obtained for Sm, Eu, Tb and Yb and better values for Ce and Nd by using LEPD Besides, LEPD allows the determination of Gd, Tm and Lu. The study of REE concentrations in the neighbourhood of two coal power stations show that in the station under construction (C.T. Pego), the index of accumulation of each REE by the lichens and olive tree leaves is identical in two sampling loci where the soils have different REE concentrations; and in the station in operation (C.T. Sines), the REE contents in the soils is identical and the differences observed in the lichens and wild terrestrial plants are most probably due to the fly-ashes emission from the station. (author) 9 refs.; 4 figs.; 6 tabs

Leachability of rare earth elements (REEs) from solid wastes generated during chemical processing of monazite

International Nuclear Information System (INIS)

Radhakrishnan, Sujata; Pillai, P.M.B.

2001-01-01

Studies have been carried out to assess the leachability of REEs from solid wastes generated in monazite processing. Leachability of REEs (La, Ce, Nd, Pr, Sm, Gd) and Y from PbS-Ba(Ra)SO 4 (Mixed cake) and Effluent Treatment Plant cake (calcium hydroxy apatite) has been studied using rain water as the leachant. Studies indicate that 23 -60 % of the REEs gets leached out from the mixed cake in the first 24 hours. From the ETP cake, the percentage of REEs leached out were negligible. The results provide inputs for hazards evaluation in accidental situations resulting in breach of integrity of the waste storages. (author)

Uranium and REE recovery from Florida phosphates – Looking back and going forward

International Nuclear Information System (INIS)

Zhang, J.; Birky, B.

2014-01-01

Uranium recovered during the production of phosphoric acid represents a significant source of nuclear fuel as the gap between uranium supply and demand is expected to grow. The phosphate industry in Florida supplied uranium to both the defense and energy sectors in the past, but market conditions ended the recovery process. Currently, the uranium is retained in the phosphoric acid and the granulated fertilizer products, diammonium and monoammonium phosphate, and dispersed on farm fields as a trace element in blended fertilizers. This represents a loss to the nuclear fuel cycle that will never be recovered. In an era of heightened awareness of sustainability and increasing pressure to reduce greenhouse gas emissions, market conditions and social factors may converge to create favorable conditions for uranium recovery to resume. However, the future may not resemble the past as uranium concentrations are lower in the newer mining areas and ion exchange challenges solvent extraction for the extraction technology of choice. New factors will also influence both the economic decision to resume recovery operations, as well as the recovery technology. Rare earth elements (REE) are also present in the processing streams at recoverable levels, and can be co-extracted with uranium using the proven solvent extraction method. REE are vital to the phosphor industry, green energy development, and technology advances in many fields. However, the world has limited REE resources, and the recovery of REE from many of these resources is both economically challenging and environmentally troublesome. Phosphate as a secondary REE resource has a great potential to fill this gap. World annual phosphate rock production has surpassed 200 million tons, representing 60,000 tons of unrecovered REE assuming an average concentration of 300 ppm. In the case of Florida, REE in the phosphate ore reports to four mining and processing streams, with approximately 10% to flotation tailings, 30-40% to

Railroad Engineering Education Symposium (REES) 2012 and 2014.

Science.gov (United States)

2016-01-25

Since its initial offering in 2008, the objective of the Railroad Engineering Education Symposium (REES) has been to develop interest among university faculty in railroad transportation engineering, with the goal of facilitating and supporting their ...

A selected thermodynamic database for REE to be used in HLNW performance assessment exercises

Energy Technology Data Exchange (ETDEWEB)

Spahiu, K; Bruno, J [MBT Tecnologia Ambiental, Cerdanyola (Spain)

1995-01-01

A selected thermodynamic database for the Rare Earth Elements (REE) to be used in the safety assessment of high-level nuclear waste deposition has been compiled. Thermodynamic data for the aqueous species of the REE with the most important ligands relevant for granitic groundwater conditions have been selected and validated. The dominant soluble species under repository conditions are the carbonate complexes of REE. The solubilities of the oxides, hydroxides, carbonates, hydroxycarbonates, phosphates and other important solids have been selected and validated. Solubilities and solubility limiting solids in repository conditions have been estimated with the selected database. At the initial stages of fuel dissolution, the UO{sub 2} matrix dissolution will determine the concentrations of REE. Later on, solid phosphates, hydroxycarbonates and carbonates may limit their solubility. Recommendations for further studies on important systems in repository conditions have been presented. 136 refs, 13 figs, 16 tabs.

A selected thermodynamic database for REE to be used in HLNW performance assessment exercises

International Nuclear Information System (INIS)

Spahiu, K.; Bruno, J.

1995-01-01

A selected thermodynamic database for the Rare Earth Elements (REE) to be used in the safety assessment of high-level nuclear waste deposition has been compiled. Thermodynamic data for the aqueous species of the REE with the most important ligands relevant for granitic groundwater conditions have been selected and validated. The dominant soluble species under repository conditions are the carbonate complexes of REE. The solubilities of the oxides, hydroxides, carbonates, hydroxycarbonates, phosphates and other important solids have been selected and validated. Solubilities and solubility limiting solids in repository conditions have been estimated with the selected database. At the initial stages of fuel dissolution, the UO 2 matrix dissolution will determine the concentrations of REE. Later on, solid phosphates, hydroxycarbonates and carbonates may limit their solubility. Recommendations for further studies on important systems in repository conditions have been presented. 136 refs, 13 figs, 16 tabs

Using REE tracers to measure sheet erosion changing to rill erosion

International Nuclear Information System (INIS)

Liu Puling; Xue Yazhou; Song Wei; Wang Mingyi; Ju Tongjun

2004-01-01

Rare Earth Elements (REE) tracer method was used to study sheet erosion changing to rill erosion on slope land. By placing different rare earth elements of different soil depth across a slope in an indoor plot, two simulated rainfalls were applied to study the change of erosion type and the rill erosion process. The results indicate that the main erosion type is sheet erosion at the beginning of the rainfalls, and serious erosion happens after rill erosion appears. Accumulated sheet and rill erosion amounts increase with the rainfalls time. The percentage of sheet erosion amount decreases and rill erosion percentage increases with time. At the end of the rainfalls, the total rill erosion amounts are 4-5 times more than sheet erosion. In this paper, a new REE tracer method was used to quantitatively distinguish sheet and rill erosion amounts. The new REE tracer method should be useful to future studying of erosion processes on slope lands. (authors)

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

Science.gov (United States)

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

2006-12-01

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

Selective electrochemical extraction of REEs from NdFeB magnet waste at room temperature

NARCIS (Netherlands)

Venkatesan, P.; Vander Hoogerstraete, Tom; Hennebel, Tom; Binnemans, Koen; Sietsma, J.; Yang, Y.

2018-01-01

NdFeB magnet waste is one of the important secondary resources from which rare-earth elements (REEs) can be recovered. Herein we present an electrochemical route to selectively extract REEs from the magnet waste at room temperature. First, the magnet waste was partially leached with HCl. The

Modeling the geochemical distribution of rare earth elements (REEs using multivariate statistics in the eastern part of Marvast placer, the Yazd province

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Amin Hossein Morshedy

2017-07-01

is to maximize both the similarity within each cluster and the difference between clusters, and finally find the structure in the data. Nowadays, cluster analysis is applied in many disciplines: biology, botany, medicine, psychology, geography, marketing, image processing, psychiatry, archaeology, etc. (Everitt et al., 2011. To execute a partitioning algorithm, the principal components analysis (PCA algorithm is applied for feature selection, feature extraction and dimension reduction. Hierarchical clustering can be utilized to provide a nested sequence of partitions with bottom-up or top-down methods based on similarity. The single linkage and complete linkage are the most popular hierarchical algorithms (Jain et al., 1999; Ji et al., 2007. Results and discussion The REE chondrite-normalized pattern for the eastern area in the Marvast placer represents a high match to the standard pattern of monazite. This pattern shows the positive anomaly of Ce and the negative anomaly of Eu. To determine the distribution of REEs concentration, 2D interpolation maps were plotted in three groups of light, middle, and heavy REEs (LREE, MREE, and HREE, which were indicated in the geochemical anomaly at the south and south-west of the area. The relative ratios of (LREE/HREE and (Ce/Eu exposed the high proportion of LREEs to HREEs. In the next section, the hierarchical clustering algorithm was employed to partition the data in the feature and sample levels. The elements portioning demonstrated four separated groups, which can be related to atomic and chemical structures. The studied region was divided into four zones by the clustering approach. The fourth zone confine coincided with the REE anomaly area. Finally, PCA was applied as the multivariate statistical tool to this dataset. Hence three principal components modeled over 90% of the variance. For the first component, the distribution map of load factor has a good agreement with anomaly area. References Alipour-Asll, M., Mirnejad

Rees Coextensions of Finite, Negative Tomonoids

Czech Academy of Sciences Publication Activity Database

Petrík, Milan; Vetterlein, T.

2017-01-01

Roč. 27, č. 1 (2017), s. 337-356 ISSN 0955-792X R&D Projects: GA ČR GPP201/12/P055 Grant - others:GA MŠk(CZ) EE2.3.20.0051 Institutional support: RVO:67985807 Keywords : totally ordered monoids * tomonoid partition * Rees coextension Subject RIV: BA - General Mathematics OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 0.909, year: 2016

Age-Dependent Changes in Resting Energy Expenditure (REE): Insights from Detailed Body Composition Analysis in Normal and Overweight Healthy Caucasians.

Science.gov (United States)

Geisler, Corinna; Braun, Wiebke; Pourhassan, Maryam; Schweitzer, Lisa; Glüer, Claus-Christian; Bosy-Westphal, Anja; Müller, Manfred J

2016-06-01

Age-related changes in organ and tissue masses may add to changes in the relationship between resting energy expenditure (REE) and fat free mass (FFM) in normal and overweight healthy Caucasians. Secondary analysis using cross-sectional data of 714 healthy normal and overweight Caucasian subjects (age 18-83 years) with comprehensive information on FFM, organ and tissue masses (as assessed by magnetic resonance imaging (MRI)), body density (as assessed by Air Displacement Plethysmography (ADP)) and hydration (as assessed by deuterium dilution (D₂O)) and REE (as assessed by indirect calorimetry). High metabolic rate organs (HMR) summarized brain, heart, liver and kidney masses. Ratios of HMR organs and muscle mass (MM) in relation to FFM were considered. REE was calculated (REEc) using organ and tissue masses times their specific metabolic rates. REE, FFM, specific metabolic rates, the REE-FFM relationship, HOMA, CRP, and thyroid hormone levels change with age. The age-related decrease in FFM explained 59.7% of decreases in REE. Mean residuals of the REE-FFM association were positive in young adults but became negative in older subjects. When compared to young adults, proportions of MM to FFM decreased with age, whereas contributions of liver and heart did not differ between age groups. HOMA, TSH and inflammation (plasma CRP-levels) explained 4.2%, 2.0% and 1.4% of the variance in the REE-FFM residuals, but age and plasma T3-levels had no effects. HMR to FFM and MM to FFM ratios together added 11.8% on to the variance of REE-FFM residuals. Differences between REE and REEc increased with age, suggesting age-related changes in specific metabolic rates of organs and tissues. This bias was partly explained by plasmaT3-levels. Age-related changes in REE are explained by (i) decreases in fat free mass; (ii) a decrease in the contributions of organ and muscle masses to FFM; and (iii) decreases in specific organ and tissue metabolic rates. Age-dependent changes in the REE

Uranium and REE potential of the albitite-pyroxenite-microclinite belt of Rajasthan, India

International Nuclear Information System (INIS)

Singh, Govind; Sharma, D.K.; Yadav, O.P.; Jain, Rajan B.; Singh, Rajendra

1998-01-01

A number of radioactive albitite, pyroxenite and microclinite occurrences have been identified in north and central Rajasthan, along or in close proximity to major lineaments, from Dancholi - Mewara in the NE to Tal in the SW. With these new findings the total extent of Albitite belt of Rajasthan now stands at over 320 km. These occurrences have been evaluated on the basis of their U, Th and REE content to identify the potential areas for the second phase of uranium exploration programme. Further, based on the various characteristic features of radioactive host rocks, the Albitite Belt has been divided into five sectors. The U 3 O 8 content of albitites varies from 0.008 to 0.44% and of pyroxenites from 0.022 to 2.0% whereas ThO 2 varies from < 0.005 to 0.83% in albitites and <0.005 to 0.033% in pyroxenities. These albitites, microclinites and pyroxenites are also characterised by anomalous concentration of REEs. Uranium and REE bearing phases are represented by uraninite, brannerite, davidite, fergusonite, monazite, anatase, rutile, zircon, allanite and britholite. The data accrued so far suggest that U and REE potential of the Mewara-Maonda and Hurra Ki Dhani-Rohil sectors are very high and hence needs further detailed integrated exploration. (author)

The Redox Dynamics of Iron in a Seasonally Waterlogged Forest Soil (Chaux Forest, Eastern France) Traced with Rare Earth Element Distribution Patterns

Science.gov (United States)

Steinmann, M.; Floch, A. L.; Lucot, E.; Badot, P. M.

2014-12-01

The oxyhydroxides of iron are common soil minerals and known to control the availability of various major and trace elements essential for biogeochemical processes. We present a study from acidic natural forest soils, where reducing redox conditions due to seasonal waterlogging lead to the dissolution of Fe-oxyhydroxides, and to the release of Fe to soil water. In order to study in detail the mechanism of redox cycling of Fe, we used Rare Earth Element (REE) distribution patterns, because an earlier study has shown that they are a suitable tool to identify trace metal sources during soil reduction in wetland soils (Davranche et al., 2011). The REE patterns of soil leachates obtained with the modified 3-step BCR extraction scheme of Rauret et al., (1999) were compared with those of natural soil water. The adsorbed fractions (F1 leach), the reducible fraction of the deepest soil horizon H4 (F2 leach, 50-120 cm), and the oxidizable fractions of horizons H2 to H4 (F3 leachs, 24-120 cm) yielded REE patterns almost identical to soil water (see figure), showing that the REE and trace metal content of soil water was mainly derived from the F1 pool, and from the F2 and F3 pools of the clay mineral-rich deep soil horizons. In contrast, the F2 leach mobilized mainly Fe-oxyhydroxides associated with organic matter of the surface soil and yielded REE patterns significantly different from those of soil water. These results suggest that the trace metal content of soil water in hydromorphic soils is primarily controlled by the clay fraction of the deeper soil horizons and not by organic matter and related Fe-oxyhydroxides of the surface soil. Additional analyses are in progress in order to verify whether the REE and trace metals of the deeper soil horizons were directly derived from clay minerals or from associated Fe-oxyhydroxide coatings. Refs cited: Davranche et al. (2011), Chem. Geol. 284; Rauret et al. (1999), J. Environ. Monit. 1.

Validade da equação de Henry e Rees que estima a taxa metabólica de repouso em adolescentes masculinos Validez de la ecuación de Henry y Rees que estima la tasa metabólica de reposo en adolescentes masculinos Validity of the equation of Henry and Rees that estimates the resting metabolic rate in male adolescents

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Paulo Henrique S. Fonseca

2011-06-01

Henry y Rees (1991 no presentó diferencia significativa respecto al método estándar, así como el error constante entre los promedios fue inferior a 5%. Sin embargo, el análisis gráfico de Bland y Altman revela que no hay concordancia entre la ecuación y el método estándar. CONCLUSIONES: La ecuación de Henry y Rees (1991 debe ser utilizada con prudencia en el cálculo de la TMR para adolescentes semejantes al grupo estudiado.OBJETCTIVE: To evaluate the validity of the equation proposed by Henry and Rees (1991 to predict resting metabolic rate in adolescent boys. METHODS: This cross-sectional study enrolled 52 boys aged ten to 17 years on a random convenience sample. The variables measured were: body mass and indirect calorimetry. Body mass was replaced in the equation of Henry and Rees to determine the predicted resting metabolic rate. The indirect calorimetry was determined by the values of O2 consumption and CO2 productions, in order to calculate Weir's equation (1949, considered in this study as the standard method to calculate resting metabolic rate. All measurements were performed in the supine position and at rest, in the morning after a six-hour fast. Statistical analysis included paired t-test; constant error (with a tolerable difference between the means <5% and Bland and Altman graphic analysis. RESULTS: The equation proposed by Henry and Rees did not show significant difference in relation to the standard method and the constant error between the means was <5%. However, Bland and Altman analysis did not show agreement between the studied equation and the standard method. CONCLUSIONS: Henry and Rees equation should be used with caution to calculate resting metabolic rate in adolescent boys with similar characteristics of the studied group.

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

Science.gov (United States)

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

2016-01-01

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

Fractionation of chemical elements including the REEs and 226Ra in stream contaminated with coal-mine effluent

International Nuclear Information System (INIS)

Centeno, L.M.; Faure, G.; Lee, G.; Talnagi, J.

2004-01-01

Water draining from abandoned open-pit coal mines in southeastern Ohio typically has a low pH and high concentrations of Fe, Al and Mn, as well as of trace metals (Pb, Cu, Zn, Ni, Co, etc.) and of the rare earth elements (REEs). The cations of different elements are sorbed selectively by Fe and Al hydroxide precipitates which form with increasing pH. As a result, the trace elements are separated from each other when the hydroxide precipitates are deposited in the channel of a flowing stream. Therefore, the low-energy environment of a stream contaminated by mine effluent is a favorable site for the chemical fractionation of the REEs and of other groups of elements with similar chemical properties. The interpretation of chemical analyses of water collected along a 30-km-stretch of Rush Creek near the town of New Lexington, Perry County, Ohio, indicates that the abundances of the REEs in the water appear to change downstream when they are normalized to the REE concentrations of the mine effluent. In addition, the Ce/La ratios (and those of all REEs) in the water decrease consistently downstream. The evidence indicates that the REEs which remain in solution are enriched La and Ce because the other REEs are sorbed more efficiently. The solid Fe(OH) 3 precipitates in the channel of Rush Creek upstream of New Lexington also contain radioactive 226 Ra that was sorbed from the water. This isotope of Ra is a decay product of 238 U which occurs in the Middle Pennsylvanian (Upper Carboniferous) coal and in the associated shale of southeastern Ohio. The activity of 226 Ra of the Fe(OH) 3 precipitates increases with rising pH, but then declines farther downstream as the concentration of Ra remaining in the water decreases

Rare earth elements determination and distribution patterns in sediments of a polluted marine environment by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Yusof, A.M.

2001-01-01

Results obtained from the analysis of sediment core samples taken from a fairly polluted marine environment were analyzed for the REE contents to determine the concentrations of La, Ce, Sm, Eu, Tb, Dy and Yb using instrumental neutron activation analysis. Core samples were divided into strata of between 2 to 3 cm intervals and prepared in the powdered form before irradiating them in a neutron flux of about 5.0 x 10 12 n x cm -2 x s -1 in a Triga Mark II reactor. Down-core concentration profiles of La, Ce, Sm, Eu, Tb, Dy and Yb in 3 core sediments from three sites are obtained. The shale-normalized REE pattern from each site was examined and later used to explain the history of sedimentation by natural processes such as shoreline erosion and weathering products deposited on the seabed and furnishing some baseline data and/or pollution trend occurring within the study area. The shale-normalized REE patterns also showed that LREE in the sediment samples exhibit enrichment relative to HREE particularly, La and Sm showing enrichment compared to the ratios in shale. REE concentrations of 124 μg/g at the surface of sediment collected at two of the three sites were found to decrease to 58 and 95 μg/g, respectively. This was of particular interest when it is used to explain the anomalies occurring in the marine sediment as a result of geochemical processes over a long period of time. Changes in concentrations from surface to bottom of the sediments ratioed to Sm concentrations and the correlation between concentrations of Sm and these elements were also investigated and correlation coefficients were calculated for all REEs and sites. Validation of the method used was done using a Soil-7 SRM. (author)

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

Science.gov (United States)

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. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Th, U, REE Backgrounds and Phytoavailability in Soils of the Padanian Plain (Northern Italy

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Dario Di Giuseppe

2014-12-01

Full Text Available In this contribution we present ICP-MS analyses carried out on agricultural soils from the eastern-most part of the Padanian plain (Ferrara Province and on the related crop products. The aim is to provide, for the first time, backgrounds for some trace elements such as rare earth elements (REE, thorium (Th, uranium (U and to understand the related phytoavailability. In particular, detailed analyses have been done on Sorghum Vulgare plants, analyzing distinct plant parts in different vegetative periods. Results indicate that a REE concentration in plant tissues is always lower than in the related soils, precluding the occurrence of bioaccumulation and b no preferential elemental uptake and REE fractionation. In this light, the observed soil/plant relationships could be used in the definition of markers of territoriality (provenance fingerprint for agricultural products.

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

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David Carpenter

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

Distribution and origin of major and trace elements (particularly REE, U and Th) into labile and residual phases in an acid soil profile (Vosges Mountains, France)

Science.gov (United States)

Aubert, D.; Probst, A.; Stille, P.

2003-04-01

Physical and chemical weathering of rocks and minerals lead to soil formation and allow the removal of chemical elements from these systems to ground- or surface waters. But most of the time the determination of element concentrations in soils is not sufficient to estimate whether they are being accumulated or what is their ability to be released in the environment. Thus, the distribution and chemical binding for a given element is very important because it determines its mobility and potential bioavailability throughout a soil profile. Heavy metals and REE (Rare Earth Elements) are particularly of environmental concern because of their potential toxicity. For most of them, their chemical form strongly depends on the evolution of physico-chemical parameters like pH or redox conditions that will induce adsorption-desorption, complexation or co-precipitation phenomena in the material. The purpose of this study is to determine the distribution of several major and trace elements (especially REE, Th and U) in an acidic forested podzolic soil profile from the Vosges Mountains (France). To achieve this goal we use a 7 step sequential extraction procedure that allows determining precisely the origin and the behaviour of particular elements in the environment (Leleyter et al., 1999). In addition we performed leaching experiments using very dilute acetic and hydrochloric acid in order to establish the origin of REE in this soil. The results of the sequential extraction indicate that most of the metals, Th and U are mainly bound to Fe oxides. Organic matter appears also to be a great carrier of P, Ca, Fe and REE even if its content is very low in the deep horizons of the soil. Moreover, we show that in each soil horizon, middle REE (MREE) to heavy REE (HREE) are more labile than light REE (LREE). Leaching experiments using dilute acid solution further suggest that in the shallowest horizons REE largely derive from atmospheric deposition whereas at greater depth, weathering

Continental shelves as potential resource of rare earth elements.

Science.gov (United States)

Pourret, Olivier; Tuduri, Johann

2017-07-19

The results of this study allow the reassessment of the rare earth elements (REE) external cycle. Indeed, the river input to the oceans has relatively flat REE patterns without cerium (Ce) anomalies, whereas oceanic REE patterns exhibit strong negative Ce anomalies and heavy REE enrichment. Indeed, the processes at the origin of seawater REE patterns are commonly thought to occur within the ocean masses themselves. However, the results from the present study illustrate that seawater-like REE patterns already occur in the truly dissolved pool of river input. This leads us to favor a partial or complete removal of the colloidal REE pool during estuarine mixing by coagulation, as previously shown for dissolved humic acids and iron. In this latter case, REE fractionation occurs because colloidal and truly dissolved pools have different REE patterns. Thus, the REE patterns of seawater could be the combination of both intra-oceanic and riverine processes. In this study, we show that the Atlantic continental shelves could be considered potential REE traps, suggesting further that shelf sediments could potentially become a resource for REE, similar to metalliferous deep sea sediments.

Geochemical and mineralogical characteristics of REE in granite-derived regolith: a model for the Southeast United States

Science.gov (United States)

Foley, Nora K.; Bern, Carleton R.; Ayuso, Robert A.; Hubbard, Bernard E.; Shah, Anjana K.

2015-01-01

Rare earth element (REE) ion-adsorption clay deposits are of global economic importance because they currently supply a significant portion of the world’s annual production of both light (LREE) and heavy REE (HREE). There is considerable ambiguity regarding the origin of

Solubilities of some hydrous REE phosphates with implications for diagenesis and sea water concentrations

International Nuclear Information System (INIS)

Jonasson, R.G.; Bancroft, G.M.; Nesbitt, H.W.

1985-01-01

Solubility product determinations suggest that the hydrous phosphates of the rare earths, REPO 4 .xH 2 O, are important in controlling the sea water REE concentrations. Two of these solids, rhabdophane, (P6 2 22) and 'hydrous xenotime', (I4 1 /amd), have been synthesized at 100 C via the acid hydrolysis of the respective REE pyrophosphate. The solubility products at infinite dilution were determined to be pK 0 = 24.5, (La at 25 C); 26.0, (Pr at 100 C); 25.7, (Nd at 100 C); and 25.5, (Er at 100 C). On the basis of calculations involving the reaction of Re 3+ with apatite to form the hydrous phosphate, the lanthanum concentration in sea water is predicted to be about 140 pmol/L. Laboratory experiments support the hypothesis that apatite is a substrate for reactions with dissolved REE. (author)

What concentration of actinides can be packed into calcite? Hints from rare earth element (REE) composition

International Nuclear Information System (INIS)

Christiansen, J.; Stipp, S.L.S.; Waight, T.; Baker, J.A.

2005-01-01

Full text of publication follows: For reliable modelling of actinide mobility in the event of spent fuel repository failure, we need data describing the uptake capacity of the minerals likely to find themselves in the transport path. Calcite (CaCO 3 ) is a common secondary mineral in fractures and pore fillings, especially downstream from degrading concrete facilities, so it is a likely candidate for incorporation. Investigations made under ACTAF, a 5. Framework EURATOM integrated project, as well as some other research studies, have shown that actinides are successfully incorporated as substituting ions within the calcite mineral structure. The question remaining, is how much can calcite take up. Geologists routinely use relative concentrations of rare Earth elements (REE's), the lanthanides, for interpreting rock genesis and history. One can also adopt them as analogues for the radioactive elements because their f-orbital electron configuration makes them behave very much like actinides. We collected and analysed a suite of 70 calcite samples from a great number of possible formation environments, geological ages and geographical locations, for the purpose of finding the range and maximum of total f-orbital substitution possible in calcite, under natural conditions. We analysed them using Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). The maximum concentration found was about 5 x 10 -3 mole/kg total REE in a sample that had a geological history of formation where REE fluids played a role. Over the whole suite, total REE ranged from less than 10 -4 moles/kg for limestone samples formed from biogenic calcite where REE-enriched fluids would have played a negligible role. Thus, in natural calcite, REE's are present and all evidence points to a structural incorporation within the mineral rather than as a separate REE-rich phase. These data compare favourably with mole fractions from calcite grown synthetically, where as much as 6 x 10 -3

Environmental impact assessment on the radioactive of a REE separation project

International Nuclear Information System (INIS)

Li Nana; Zhu Yucheng; Cai Minqi

2011-01-01

Based on the investigation of field actual environment and analysis of radioactive sources, and industrial process techniques, environmental impact of the radioactive from a REE separation project has been analyzed, assessed and forecasted. The investigation and monitoring of actual radioactive in the environment indicated that value of assessment factors remained within the range of natural background level as a whole. The maximum annual individual effective dose for occupational worker and the public were forecasted and were found to be 1.622 mSv/a and 0.029 mSv/a respectively. Both of the values are lower than annual dose limit respectively. The radioactive impact of this project on the environment will comply with the standard limit of law and requirements after the reservation measures are carried out to REE. (authors)

Geochemistry of trace elements and REE in phosphate deposits of el Sibaiya west AREA, nile valley

International Nuclear Information System (INIS)

Aly, M.M.; Hussein, H.A.; Elkammar, A.A.; Mahdy, A.I.

1994-01-01

The present work deals essentially with the study of the geochemistry of trace elements and rare earth elements (REE s) patterns in the upper cretaceous phosphate deposit in El Sibaiya west area located on the western side of the River Nile. About 20 Km south from Esna town, upper Egypt. It was evident throughout this study that the average shale normalized pattern of six analyzed rare earth elements indicates that the phosphate deposits under study were deposited under marine environment. In addition some geochemical ratios such as Cl/Br and Na/Br have been proposed as indicators of the paleosalinity of the upper cretaceous tethys compared with the nowadays sea. Uranium equilibrium status of the studied phosphate deposits suggests a remarkably secondary enrichment at the lower horizon at the expense of the upper one due to downward leaching. Such secondary enrichment of uranium is thought to take place under oxidizing vadose conditions by the action of descending meteoric water. 6 fig., 4 tab

The role of pegmatites and acid fluids for REE/HFSE mobilization in the Strange Lake peralkaline granitic pluton, Canada

Science.gov (United States)

Gysi, A. P.; Williams-Jones, A.

2012-12-01

The Strange Lake pluton in Canada is a mid-Proterozoic peralkaline granitic intrusion that is host to a world-class rare earth element (REE), yttrium (Y) and high-field strength element (HFSE) deposit containing more than 50 Mt ore at >1.5 wt.% REE and >3 wt.% Zr. The highest REE/HFSE concentrations are found in pegmatite-rich zones characterized by intense alteration. Previous studies of Strange Lake and other peralkaline and alkaline intrusions, such as Khan Bogd (Mongolia) and Tamazeght (Morocco) plutons have shown that hydrothermal alteration may play an important role in the mobility of the REE/HFSE. However, the fluid chemistry and conditions of alteration (i.e., P, T, pH, fO2, ligand activity) in these systems still need to be constrained to evaluate the importance and scale of such hydrothermal mobilization. We present new data from the B-zone, a pegmatite-rich zone located in NW Strange Lake. The pegmatites are generally zoned and form two main types. The border-type pegmatites consist of quartz, K-feldspar and hematized aegirine, whereas volatile-rich pegmatites consist of hydrothermal quartz and fluorite. Transitions between both types were also observed, with the K-feldspar being partly altered and replaced by Al-Si-rich phyllosilicates. The heavy (H)REE and Zr were primarily concentrated in zirconosilicates such as elpidite, now pseudomorphed by zircon or gittinsite, whereas light (L)REE and Y were concentrated in REE-F-(CO2)-minerals such as fluocerite and bastnäsite. Textural and mineralogical observations indicate that these minerals are primary and were partly to completely leached upon fluid-rock interaction in the pegmatites. Secondary phases include Ca-F-Y-rich minerals, mainly hydrothermal fluorite, that fill vugs and replaced primary REEHFSE minerals. The presence of hydrothermal fluorite veins, micro-veins, vugs and micro-breccia in the most altered parts of the B-zone are interpreted to reflect interaction of the rocks with a F-rich fluid

Determination of Th and REE in columbite - tantalite samples by ICP-OES

International Nuclear Information System (INIS)

Hanuman, V.V.; Khorge, C.R.; Radhamai, R.; Nair, Sajitha; Srivastava, P.K.

2007-01-01

A simple method of decomposition and separation of Th and REE in columbite- tantalite is developed for determination by ICP- OES. The sample is decomposed with hydrofluoric and hydrochloric acid in presence of little sulphuric acid to avoid drying on water bath. Th and rare earths are separated as fluoride together with undecomposed sample. The residue is fused with a 1: 1 mixture of sodium di hydrogen orthophosphate and sodium pyrophosphate. The melt is dissolved in water for measurement. Nitric acid is found unsuitable due to loss in Ce in some of the samples. Matrix elements (more than 97.5) are removed in single step by both the treatments. The free cassiterite present in samples is not attacked during acid digestion. However, the same is easily decomposed in fusion. U (IV) is also precipitated along with Th and REE when hydrochloric acid is used. As expected uranium is lost when nitric acid is used. The results are compared with existing well-established procedure involving peroxide fusion for decomposition; hydroxide and fluoride precipitation separation. Both the methods yielded comparable result. The method is simple, comparatively rapid and suitable for routine application for determination of REE , Th and U(IV) content. The RSD of the method was found to be in the range of 1- 1.5% for various elements. (author)

Discrete event simulation of NASA's Remote Exploration and Experimentation Project (REE)

Science.gov (United States)

Dunphy, J.; Rogstad, S.

2001-01-01

The Remote Exploration and Experimentation Project (REE) is a new initiative at JPL to be able to place a supercomputer on board a spacecraft and allow large amounts of data reduction and compression to be done before science results are returned to Earth.

Mineralogy and geochemistry of REE-Zr-Nb mineralised nepheline syenites in the peralkaline Ilímaussaq complex, South Greenland

DEFF Research Database (Denmark)

Borst, Anouk Margaretha

Summary: The rare earth elements (REE) share unique physical, chemical and light-emitting properties that are of great importance to the high-tech industry. Among the many rocks containing appreciable amounts of REE, alkaline igneous rocks and carbonatites provide important resources for these el...

Distribution of rare earth elements in marine sediments from the Strait of Sicily (western Mediterranean Sea): Evidence of phosphogypsum waste contamination

International Nuclear Information System (INIS)

Tranchida, G.; Oliveri, E.; Angelone, M.; Bellanca, A.; Censi, P.; D'Elia, M.; Neri, R.; Placenti, F.; Sprovieri, M.; Mazzola, S.

2011-01-01

Graphical abstract: Coastal recent sediments from the Strait of Sicily showed elevated concentrations of REE associated to high Th concentrations. The shale-normalized REE + Y patterns are characterized by MREE enrichments relative to HREE and LREE, manifested with a convexity along the patterns. Sm n /La n ratio, indicative of MREE enrichments, showed a significant correlation with the Th concentration. This positive correlation supports the origin of these elements by phosphogypsum-contaminated effluents from an industrial plant, located in the southern Sicilian coast. Research highlights: → REE + Y contents are higher in onshore than offshore sediments. → Anomaly in sediments near southwestern Sicilian coast (site 134): high REE + Y. → REE + Y patterns show Middle REE enrichments (convexity around Sm-Gd-Eu elements). → Sm n /La n, measure of MREE enrichments, is correlated with high Th concentrations. → Anomalies are associated with the input of phosphogypsum-contaminated effluents. - Abstract: Concentrations of rare earth elements (REE), Y, Th and Sc were recently determined in marine sediments collected using a box corer along two onshore-offshore transects located in the Strait of Sicily (Mediterranean Sea). The REE + Y were enriched in offshore fine-grained sediments where clay minerals are abundant, whereas the REE + Y contents were lower in onshore coarse-grained sediments with high carbonate fractions. Considering this distribution trend, the onshore sediments in front of the southwestern Sicilian coast represent an anomaly with high REE + Y concentrations (mean value 163.4 μg g -1 ) associated to high Th concentrations (mean value 7.9 μg g -1 ). Plot of shale-normalized REE + Y data of these coastal sediments showed Middle REE enrichments relative to Light REE and Heavy REE, manifested by a convexity around Sm-Gd-Eu elements. These anomalies in the fractionation patterns of the coastal sediments were attributed to phosphogypsum

The influence of fluorine on phase relations and REE enrichment in alkaline magmas

Science.gov (United States)

Beard, C. D.; van Hinsberg, V.; Stix, J.; Wilke, M.

2017-12-01

Fluorine is a minor element in most magmas, but higher concentrations to wt% levels have been reported in alkaline systems, including those which host economic deposits of REE + HFSE1. Despite low abundance in most natural melts, fluorine has received great attention from the experimental community because it has a strong influence on melt structure, lowering melting points and drastically reducing viscosity. The effect of fluorine on element speciation has important implications for phase relations and the partitioning of trace elements between minerals and melts, thus metal enrichment processes in alkaline magmas. We have experimentally investigated the impact of fluorine on phase relations and partitioning of rare metals, the REE in particular, in evolved alkaline melts. Synthetic glasses of tephriphonolite to phonolite composition were doped with a wide range of elements at trace levels, and fluorine contents were varied from fluorine-free to 2.5 wt%. Experiments were performed water-saturated in an internally heated pressure vessel at 200 MPa with log fO2 at ca. QFM+1, which represents the intrinsic redox conditions of the setup. Charges were heated to super-liquidus conditions for 16 hours, cooled slowly (1˚C/min) to run temperature and subsequently equilibrated for at least 40 hours. Run products were analysed by EPMA and LA-ICP-MS. The experiments produce an equilibrium assemblage of sodic pyroxene, biotite, Fe-oxide, melt, fluid, ±K-feldspar, ±titanite, ±fluorite. Addition of fluorine markedly increases the mode of biotite, which initially buffers melt F content at low levels (< 0.2 wt%). Only in experiments with more than 0.6 wt% F do we observe a significant increase in the melt F-content. Here, fluorine decreases pyroxene/melt partitioning coefficients equally for all REE where pyroxene composition and P-T conditions are equivalent (ca. 1/2 with 0.6% F). We suggest that the formation of REE-F complexes in the melt2 lowers the availability of metals

The criteria for the Cohen-Macaulayness and Gorensteiness of Rees algebras of ideals having positive analytic deviation

International Nuclear Information System (INIS)

Duong Quoc Viet.

1994-06-01

This paper investigates the relationships between the maximal reduction number and q-invariant of a graded ring in the case of Rees ring being a Cohen-Macaulay or Gorenstein ring. From these relationships we give the criteria for Rees algebra of the ideal I having arbitrary analytic deviation to be Cohen-Macaulay and Gorenstein in terms of associated graded ring and maximal reduction number of I. (author). 16 refs

Release of U, Th, and REE from granitic rock: A mineralogical approach

International Nuclear Information System (INIS)

Markovaara-Koivisto, M.

2006-01-01

Finland plans to dispose of its spent nuclear fuel deep in the bedrock, and comprehensive assessment of the potential risks is required. One risk is glaciations induced by climate change, which might eventually cause malfunction of the engineered barrier system and breakdown of the copper-iron canisters containing the spent fuel. The fuel might then come into contact with groundwater. This groundwater might be acidic rain water, or oxygenated glacial melt water, which intrudes into the bedrock with hydrostatic pressure under the ice sheet. In this study, behaviour of uranium and rare earth elements was investigated in the Palmottu uranium deposit. Studies in the Palmottu deposit provide an indication of how uranium and other harmful elements could migrate from the repository to the surrounding bedrock in the event the canisters were breached. The spent fuel contains uranium and other actinides. The possible release of these elements and their behaviour after release in bedrock and groundwater were studied by means of chemical analogues occurring in nature, namely uranium (U), thorium (Th) and rare earth elements (REE). The study was focused on the mode of occurrence of these elements in granitic rocks. The chemistry of the mineral phases was explored by scanning electron microscopy and wavelength dispersive spectrometry, while the release of the elements was investigated with leaching experiments. In the first phase the samples were leached with artificial groundwater. In the second phase a HNO 3 solution of pH 5 was used, and in the final step a solution of pH 3. The U, Th and REE phases after each leaching were studied by fieldemission scanning electron microscopy and energy dispersive XRay microanalysis (EDAX), and the leachates were analysed by mass spectrometry (ICPMS and ICPAES). The aim of this study was to clarify how U, Th and REEs behave in the leaching processes associated with solutions simulating possible natural water conditions in the bedrock and to

A rapid sample decomposition procedure for bromo-heavies containing ferruginous material: determination of REEs and thorium by ICP-AES

International Nuclear Information System (INIS)

Khorge, C.R.; Murugesan, P.; Chakrapani, G.

2013-01-01

A rapid method of sample decomposition and dissolution for bromoform heavies is described for the determination of REEs and thorium by inductively coupled plasma- optical emission spectrometry. For application to geochemical exploration to achieve the high sample throughput; a simple and rapid analytical procedure is a prerequisite. In order to speed-up the existing methodology, phosphate fusion was introduced for decomposition of samples. In the proposed method, bromoform-heavies material are fused with 1:1 mixture of sodium dihydrogen orthophosphate and tetra-sodium pyrophosphate and dissolved in distilled water. After disintegration of melt, the solution was subjected to oxalate precipitation followed by R 2 O 3 separation for separating the REEs from major matrix interfering elements. The rare earth elements and thorium in the resultant solution were determined by ICP-OES. The results are compared with the results obtained by well-established existing dissolution procedures involving HF-HCl-HClO 4 acid treatment and NaF/KHF 2 fusion followed by H 2 SO 4 acid fuming. The accuracy of the method was evaluated by doping the phosphate blank with known amount of REEs and comparing the recoveries obtained using the present method. The method is simple, rapid and is suitable for the routine determination of REEs and Th in bromoform-heavies. The RSD of the method was found to be within 1-3% for Th and REEs by ICP-AES. (author)

Spectral response of REE3+ doped LaAlO3

International Nuclear Information System (INIS)

Boronat, C.; Correcher, V.; Garcia G, J.; Morales, A.; Zarate, J.; Rivera, T.

2016-10-01

This paper reports on the preliminary results obtained from the cathodoluminescence (Cl) and thermoluminescence (Tl) properties of undoped LaAlO 3 (LAO) and LaAlO 3 : REE (REE=Dy 3+ , Pr 3+ and Eu 3+ ) to be potentially employed for dosimetric purposes. The samples were synthesized by a sol-gel process based on the Pechini 's method with a spray-drying technique and, subsequently, characterized by environmental scanning electron microscopy and energy dispersive X-ray analysis spectrometry. Cl spectra display sharp and narrow wavebands that could specifically be associated with structural (in the range of 300-450 nm) and point defects (from 450 to 800 nm). The observed wavebands could be assigned as follows: (i) 480 and 570 from the Dy-doped LAO should corresponding respectively to 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 transitions, (II) 490-638 from the Pr-doped LAO is linked to 3 P 0 → 3 H 4 , 1 D 2 → 3 H 4 transitions and (III) 590 and 620 where the dopant Eu 3+ gives rise to 5 D 0 → 7 F 1 and 5 D 0 → 7 F 2 transitions and (IV) a UV-blue broad band is associated with NBOHC in undoped LAO. Such emissions are due to the presence of the 4f electrons of rare earth ions that are shielded by the outer 5s and 5p electrons, the intra-4f emission spectra of REE. Furthermore, the study performed on the Tl emission of LaAlO 3 :Dy 3+ displays (i) two maxima centred at 150 and 240 degrees Celsius (ratio 1:2) similarly to the Pr 3+ doped sample but with 7:5 of ratio. And (II) the highest radiation sensitivity, allowing us to think on the potential use of this material for dosimetric purposes, however further works are necessary to confirm such assertion. (Author)

REE in some tertiary volcanic complexes in the Republic of Macedonia

International Nuclear Information System (INIS)

Tasev, Goran; Serafimovski, Todor

2009-01-01

Petrological and geochemical features of the Tertiary magmatic rocks from the Republic of Macedonia were subject of study in this paper. The latest K-Ar, 87 Sr/ 86 Sr, and REE data for samples from Kratovo- Zletovo, Sasa-Toranica and Damjan-Buchim ore districts are presented. Whole rock XRF analyses confirmed host rock composition as dacites, quartz-latites, trachyandesites, rhyolites and rhyodacites. Absolute age determinations by the K-Ar dating method have shown ages range from 31 to 14 Ma confirming Oligocene-Miocene age as previously determined by relative methods. Determinations of 87 Sr/ 86 Sr ratios (0.70504 to 0.71126) suggest material is sourced from the contact zone between the lower crust and upper mantle where contamination of primary melt occurred. New REE data including negative Eu anomalies along with previously determined La/Yb ratios ranging from 13.3 to 43.0 (Serafimovski 1990) confirm inferred material source. These new data reconfirm previous results, provide insight into the Tertiary magmatic history of the district, and suggest the exact origin of the material that produced the Tertiary magmatic rocks.

A model for Nb-Zr-REE-Ga enrichment in Lopingian altered alkaline volcanic ashes: Key evidence of H-O isotopes

Science.gov (United States)

Dai, Shifeng; Nechaev, Victor P.; Chekryzhov, Igor Yu.; Zhao, Lixin; Vysotskiy, Sergei V.; Graham, Ian; Ward, Colin R.; Ignatiev, Alexander V.; Velivetskaya, Tatyana A.; Zhao, Lei; French, David; Hower, James C.

2018-03-01

Clay-altered volcanic ash with highly-elevated concentrations of Nb(Ta), Zr(Hf), rare earth elements (REE), and Ga, is a new type of critical metal deposit with high commercial prospects that has been discovered in Yunnan Province, southwest China. Previous studies showed that the volcanic ashes had been subjected to hydrothermal fluids, the nature of which, however, is not clear. Here we show that the volcanic ashes were originated from alkaline magmatism, followed by a continuous hydrothermal-weathering process. Heated meteoric waters, which were sourced from acidic rains and mixed with CO2 from degassing of the Emeishan plume, have caused partial, but widespread, acidic leaching of Nb, Ta, Zr, Hf, REE, and Ga into ground water and residual enrichment of these elements, along with Al and Ti, in the deeply altered rocks. Subsequent alteration occurring under cooler, neutral or alkaline conditions, caused by water-rock interaction, resulted in precipitation of the leached critical metals in the deposit. Polymetallic mineralization of similar origin may be found in other continental regions subjected to explosive alkaline volcanism associated with deep weathering in humid conditions.

Thermal decomposition of agardites (REE) - relationship between dehydroxylation temperature and electronegativity

International Nuclear Information System (INIS)

Frost, Ray L.; Erickson, Kristy L.; Weier, Matt L.; McKinnon, Adam R.; Williams, Peter A.; Leverett, Peter

2005-01-01

The thermal decomposition of a suite of synthetic agardites of formula ACu 6 (AsO 4 ) 2 (OH) 6 ·3H 2 O where A is given by a rare earth element has been studied using thermogravimetric analysis techniques. Dehydration of the agardites occurs at low temperatures and over an extended temperature range from ambient to around 60 deg. C. This loss of water is attributed to the loss of zeolitic water. The mass loss of water indicates 3 mol of zeolitic water in the structure. Dehydroxylation occurs in steps over a wide range of temperatures from 235 to 456 deg. C. The mass loss during dehydroxylation shows the number of moles of hydroxyl units is six. There is a linear relationship between the first dehydroxylation temperature and the electronegativity of the agardites (REE)

Comparison of mantle lithosphere beneath early Triassic kimberlite fields in Siberian craton reconstructed from deep-seated xenocrysts

Directory of Open Access Journals (Sweden)

I.V. Ashchepkov

2016-07-01

Kharamai mantle clinopyroxenes represent three geochemical types: (1 harzburgitic with inclined linear REE, HFSE troughs and elevated Th, U; (2 lherzolitic or pyroxenitic with round TRE patterns and decreasing incompatible elements; (3 eclogitic with Eu troughs, Pb peak and high LILE content. Calculated parental melts for garnets with humped REE patterns suggest dissolution of former Cpx and depression means Cpx and garnets extraction. Clinopyroxenes from Ary-Mastakh fields show less inclined REE patterns with HMREE troughs and an increase of incompatible elements. Clinopyroxenes from Kuranakh field show flatter spoon-like REE patterns and peaks in Ba, U, Pb and Sr, similar to those in ophiolitic harzburgites. The PT diagrams for the mantle sections show high temperature gradients in the uppermost SCLM accompanied by an increase of P-Fe#Ol upward and slightly reduced thickness of the mantle keel of the Siberian craton, resulting from the influence of the Permian–Triassic superplume, but with no signs of delamination.

Environmental Characteristics of Carbonatite and Alkaline Intrusion-related Rare Earth Element (REE) Deposits

Science.gov (United States)

Seal, R. R., II; Piatak, N. M.

2017-12-01

Carbonatites and alkaline intrusions are important sources of REEs. Environmental risks related to these deposit types have been assessed through literature review and evaluation of the geochemical properties of representative samples of mill tailings and their leachates. The main ore mineral in carbonatite deposits is bastnasite [(Ce,La)(CO3)F], which is found with dolomite and calcite ( 65 %), barite (20 - 25 %), plus a number of minor accessory minerals including sulfides such as galena and pyrite. Generally, alkaline intrusion-related REE deposits either occur in layered complexes or with dikes and veins cutting alkaline intrusions. Such intrusions have a more diverse group of REE ore minerals that include fluorcarbonates, oxides, silicates, and phosphates. Ore also can include minor calcite and iron (Fe), lead (Pb), and zinc (Zn) sulfides. The acid-generating potential of both deposit types is low because of a predominance of carbonate minerals in the carbonatite deposits, the presence of feldspars and minor calcite in alkaline intrusion-related deposits, and to only minor to trace occurrence of potentially acid-generating sulfide minerals. Both deposit types, however, are produced by igneous and hydrothermal processes that enrich high-field strength, incompatible elements, which typically are excluded from common rock-forming minerals. Elements such as yttrium (Y), niobium Nb), zirconium (Zr), hafnium (Hf), tungsten (W), titanium (Ti), tantalum (Ta), scandium (Sc), thorium (Th), and uranium (U) can be characteristic of these deposits and may be of environmental concern. Most of these elements, including the REEs, but with the exception of U, have low solubilities in water at the near-neutral pH values expected around these deposits. Mill tailings from carbonatite deposits can exceed residential soil and sediment criteria for Pb, and leachates from mill tailings can exceed drinking water guidelines for Pb. The greatest environmental challenges, however, are

Time-resolved interaction of seawater with gabbro: An experimental study of rare-earth element behavior up to 475 °C, 100 MPa

Science.gov (United States)

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

2017-01-01

High metal and rare-earth element (REE) concentrations with unusual ('atypical') normalized REE patterns are documented in fluids from active hydrothermal vent fields on the Mid-Atlantic Ridge, 5°S and the East Scotia Ridge. Those fluids show relative enrichment of middle heavy REEs and almost no Eu anomalies in chondrite-normalized patterns. To understand the processes that produce such atypical REE patterns we ran a series of experiments, in which natural bottom seawater or aqueous solutions (NaCl, NaCl-MgCl2, or NaCl-CaCl2) were reacted with gabbro and gabbro mineral assemblages from 300 to 475 °C and 40 and 100 MPa. These P-T conditions are representative for water-rock interactions in hydrothermal root and discharge zones. Fluid flux variability and kinetics were addressed in the experiments by varying the water-to-rock mass ratio (w/r) from 0.5-10 and using different run durations from 3-720 h. Only seawater and synthetic MgCl2-bearing fluid mobilized significant amounts of REEs, Si, Ca, Fe, and Mn from gabbro, from clinopyroxene, and from plagioclase. At 425 °C and 40 MPa, fluids were initially acidic with pH (25 °C) of ∼2 increasing to values between ∼4 and 7 upon progressing reactions. Rare earth element and Fe contents peaked within 3-6 h after interaction with gabbroic mineral grains (125-500 μm) at w/r of 5 (REEs) and 2-5 (Fe) but decreased with continuing reaction without strong REE fractionation. Most of the REEs that were leached from primary minerals and dissolved in the fluids early became redeposited into solid reaction products after 720 h. Contents of dissolved SiO2 were pressure-dependent, being about twofold higher at 100 MPa than at 40 MPa (425 °C) and were below quartz saturation with gabbro and clinopyroxene as solid starting material and close to quartz saturation with plagioclase reactant. However, Si in fluids from the rock-dominated experiments at 100 MPa with gabbro (w/r 0.5-1) dropped to very low contents. A concomitant

Leaching kinetics of neodymium in sulfuric acid of rare earth elements (REE) slag concentrated by pyrometallurgy from magnetite ore

Energy Technology Data Exchange (ETDEWEB)

Yoon, Ho-Sung; Kim, Chul-Joo; Chung, Kyung Woo; Lee, Jin-Young; Shin, Shun Myung [Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon (Korea, Republic of); Lee, Su-Jeong; Joe, A-Ram; Lee, Se-Il; Yoo, Seung-Joon [Seonam University, Asan (Korea, Republic of)

2014-10-15

We studied the leaching kinetics of recovering neodymium in sulfuric acid from the rare earth elements (REE) slag concentrated by smelting reduction from a magnetite ore containing monazite. The leaching kinetics on neodymium was conducted at a reactant concentration of 1.5 g REE slag per L of 0.3M H{sub 2}SO{sub 4}, agitation of 750 rpm and temperature ranging from 30 to 80 .deg. C. Neodymium oxide included in the REE slag was completely converted into neodymium sulfate phase (Nd{sub 2}(SO{sub 4}){sub 3}) in H{sub 2}SO{sub 4} after the leaching of 5 h, 80 .deg. C. As a result, the leaching mechanism was determined in a two-stage model based on the shrinking core model with spherical particles. The first step was determined by chemical reaction, and the second step was determined by ash layer diffusion because the leaching of REEs by the first chemical reaction increases the formation of the ash layer affecting as a resistance against the leaching. By using the Arrhenius expression, the apparent activation energy of the first chemical reaction step was found to be 9 kJmol{sup -1}. After the first chemical reaction, leaching reaction rate was determined by the ash layer diffusion. The apparent activation energy of ash layer diffusion was found to be 32 kJmol{sup -1}.

Leaching kinetics of neodymium in sulfuric acid of rare earth elements (REE) slag concentrated by pyrometallurgy from magnetite ore

International Nuclear Information System (INIS)

Yoon, Ho-Sung; Kim, Chul-Joo; Chung, Kyung Woo; Lee, Jin-Young; Shin, Shun Myung; Lee, Su-Jeong; Joe, A-Ram; Lee, Se-Il; Yoo, Seung-Joon

2014-01-01

We studied the leaching kinetics of recovering neodymium in sulfuric acid from the rare earth elements (REE) slag concentrated by smelting reduction from a magnetite ore containing monazite. The leaching kinetics on neodymium was conducted at a reactant concentration of 1.5 g REE slag per L of 0.3M H 2 SO 4 , agitation of 750 rpm and temperature ranging from 30 to 80 .deg. C. Neodymium oxide included in the REE slag was completely converted into neodymium sulfate phase (Nd 2 (SO 4 ) 3 ) in H 2 SO 4 after the leaching of 5 h, 80 .deg. C. As a result, the leaching mechanism was determined in a two-stage model based on the shrinking core model with spherical particles. The first step was determined by chemical reaction, and the second step was determined by ash layer diffusion because the leaching of REEs by the first chemical reaction increases the formation of the ash layer affecting as a resistance against the leaching. By using the Arrhenius expression, the apparent activation energy of the first chemical reaction step was found to be 9 kJmol -1 . After the first chemical reaction, leaching reaction rate was determined by the ash layer diffusion. The apparent activation energy of ash layer diffusion was found to be 32 kJmol -1

Geochemistry of rare earth elements in the Baba Ali magnetite skarn deposit, western Iran – a key to determine conditions of mineralisation

Directory of Open Access Journals (Sweden)

Zamanian Hassan

2016-03-01

Full Text Available The Baba Ali skarn deposit, situated 39 km to the northwest of Hamadan (Iran, is the result of a syenitic pluton that intruded and metamorphosed the diorite host rock. Rare earth element (REE values in the quartz syenite and diorite range between 35.4 and 560 ppm. Although the distribution pattern of REEs is more and less flat and smooth, light REEs (LREEs in general show higher concentrations than heavy REEs (HREEs in different lithounits. The skarn zone reveals the highest REE-enriched pattern, while the ore zone shows the maximum depletion pattern. A comparison of the concentration variations of LREEs (La–Nd, middle REEs (MREEs; Sm–Ho and HREEs (Er–Lu of the ore zone samples to the other zones elucidates two important points for the distribution of REEs: 1 the distribution patterns of LREEs and MREEs show a distinct depletion in the ore zone while representing a great enrichment in the skarn facies neighbouring the ore body border and decreasing towards the altered diorite host rock; 2 HREEs show the same pattern, but in the exoskarn do not reveal any distinct increase as observed for LREEs and MREEs. The ratio of La/Y in the Baba Ali skarn ranges from 0.37 to 2.89. The ore zone has the highest La/Y ratio. In this regard the skarn zones exhibit two distinctive portions: 1 one that has La/Y >1 beingadjacent to the ore body and; 2 another one with La/Y < 1 neighbouring altered diorite. Accordingly, the Baba Ali profile, from the quartz syenite to the middle part of the exoskarn, demonstrates chiefly alkaline conditions of formation, with a gradual change to acidic towards the altered diorite host rocks. Utilising three parameters, Ce/Ce*, Eu/Eu* and (Pr/Ybn, in different minerals implies that the hydrothermal fluids responsible for epidote and garnet were mostly of magmatic origin and for magnetite, actinolite and phlogopite these were of magmatic origin with low REE concentration or meteoric water involved.

Unravelling the sulphur isotope systematics of an alkaline magmatic province: implications for REE mineralization and exploration

Science.gov (United States)

Hutchison, W.; Finch, A.; Boyce, A.; Friis, H.; Borst, A. M.; Horsburgh, N. J.

2017-12-01

Some of the world's best alkaline rare earth element (REE) deposits are formed in magmatic systems that are sealed (i.e., those that are autometasomatised and maintain reducing conditions). Conversely, in open systems where oxidizing fluids infiltrate, it is commonly assumed that REE are redistributed over a wider (less concentrated) zone. Sulphur isotope fractionation is sensitive to variations in temperature and redox, and, although sulphide minerals are relatively abundant in alkaline systems, there have been few attempts to test these hypotheses and develop a sulphur isotope proxy for alkaline metasomatism and formation of associated REE deposits. The Gardar Rift Province in southern Greenland was volcanically active in two periods between 1300 and 1100 Ma and is an ideal natural laboratory to explore sulphur isotope systematics because a near-complete alkaline magmatic lineage is exposed. We present new δ34S from across the province with a particular focus on three alkaline systems (Ilímaussaq, Motzfeldt and Ivigtût) that also host major REE deposits. Primitive mafic rocks from regional Gardar dykes and lavas have a restricted range of δ34S between 0 and 3 ‰ and fractional crystallization imparts no observable change in δ34S. In a few cases high-δ34S rocks (>15 ‰) occur when intrusive units have assimilated local sedimentary crust (δ34S = 25 ‰). Most δ34S variation takes place in the roof zones of alkaline intrusions during late-magmatic and hydrothermal stages, and we identify clear differences between the complexes. At Ilímaussaq, where the magmatic series is exceptionally reduced (below QFM buffer), roof zone δ34S remains narrow (0-3 ‰). At Motzfeldt, a more open oxidizing roof zone (MH buffer), δ34S ranges from -12 ‰ in late-stage fluorite veins to +12 ‰ where local crust has been assimilated. Ivigtût is intermediate between these end-members varying between -5 to +5 ‰. The δ34S variations primarily relate to temperature and

Simultaneous determinations of U-Pb age and REE abundances for zircons using AfF excimer laser ablation-ICPMS

International Nuclear Information System (INIS)

Iizuka, Tsuyoshi; Hirata, Takafumi

2004-01-01

Using a laser-ablation-inductively coupled plasma mass spectrometer (LA-ICPMS), U-Pb age and rare earth element (REE) abundances have been determined simultaneously from a single 20 μm ablation pit of zircon. The laser ablation system utilizing 193 nm wave-length ArF excimer laser produces stable and reproducible signal intensities resulted in good precisions on measurements of element concentrations and isotopic ratios. Because of the higher energy density of the deep ultra-violet laser beam, ablation fractionation between Pb and U were reduced even with the prolonged ablation, and thus accuracy of Pb-U age was improved significantly. A chicane-type ion lens system was applied to a quadrupole-based ICPMS instrument. With the chicane ion lens, higher elemental sensitivity (4 times or light mass range and 3 times for mid to heavy mass range) and lower white background ( 238 U- 206 Pb ages for Nancy standard zircon (Nancy 91500), SHRIMP calibration standard zircon (SL13) and Antarctic zircon (PMA7) obtained in this study were 1064 ± 24 Ma, 569 ± 78 Ma and 2438 ± 101 Ma (2-sigma), respectively. Relative age differences from previous reports were 0.2%, 0.4% and 3.2% respectively, demonstrative of high reliability of the method. The REE abundances in zircon samples were calibrated using a NIST 610 glass standard reference material. The resulting REE abundance data for zircons (Nancy 91500 and SL13) show good agreement with those for literature values within the analytical precision of ∼20%. The matrix effect that may occur between the synthetic glass standard and zircon crystals is obviously smaller than the precision and thus negligible for this precision levels. The data presented here demonstrate clearly that the combination of ArF excimer laser an ICPMS equipped with the chicane ion lens has a potential to become a significant tool for zircon geochemistry. (author)

Petrological mineralogical and geochemical characterization of the granitoids and fracture fillings developed in Ratones Mines (Spain); Caracterizacion petrologica, mineralogica, geoquimica y evaluacion del comportamiento geoquimico de las REE en la fase solida (granitoides y rellenos fisurales) del sistema de interaccion agua-roca delentorno de la Mina Ratones

Energy Technology Data Exchange (ETDEWEB)

Buil Gutierrez, B [Ciemat. Madrid (Spain)

2002-07-01

The petrological, mineralogical and geochemical characterisation of the granitoids and fracture fillings developed in the Ratones Mine (Caceres, Spain) has been done in order to understand rock-water interaction processes which control water geochemical parameters. Special interest has been devoted to the analysis and interpretation of REE patterns in the solid phase (granitoids and fracture fillings) because they constitute geochemical tracers in water-rock interaction process. Moreover, REE are considered as actinide analogues. In order to characterise the solid phase (granitoids and fracture fillings) several investigation scales (system, outcrop, whole rock, mineral and geochemical components) have been considered and different types of samples have been analysed. These factors control the methodological approach used in this investigation. The analytical methods we have used in this investigation are microscope, qualitative and semi-quantitative methods (XRD, SEM,EDAX) and quantitative methods (ICP-MS, XRF, EM, LAM-IC-MS). The bulk of the granitoids located around the Ratones Mine Belongs to the alkaline feldspar granite-sienogranite lihotype and they show a peraluminous and subalkaline pattern. From the mineralogical point of view, they are composed by quartz, K-feldspar (Or>90%), showing sericitation, moscovitization and turmolinization altherations, alkaline plagioclase (An-=-3%), usually altered to sericite, saussirite and less frequently affected by moscovitization processes, Fe-Al biotite, frequently affected by chloritization processes and sometimes replaced by muscovite, and finally muscovite (>2% celadonite and <4% paragonite) both of primary and secondary origin. The differences observed between the different lithotypes are related with the modal proportion of the principal minerals,with the presence or absence of certain accessory minerals ( turmaline, cordierite), with specific textural patterns, grain size and also with the richness in specific

Rare earth element geochemistry characteristics of seawater and porewater from deep sea in western Pacific.

Science.gov (United States)

Deng, Yinan; Ren, Jiangbo; Guo, Qingjun; Cao, Jun; Wang, Haifeng; Liu, Chenhui

2017-11-28

Deep-sea sediments contain high concentrations of rare earth element (REE) which have been regarded as a huge potential resource. Understanding the marine REE cycle is important to reveal the mechanism of REE enrichment. In order to determine the geochemistry characteristics and migration processes of REE, seawater, porewater and sediment samples were systematically collected from the western Pacific for REE analysis. The results show a relatively flat REE pattern and the HREE (Heavy REE) enrichment in surface and deep seawater respectively. The HREE enrichment distribution patterns, low concentrations of Mn and Fe and negative Ce anomaly occur in the porewater, and high Mn/Al ratios and low U concentrations were observed in sediment, indicating oxic condition. LREE (Light REE) and MREE (Middle REE) enrichment in upper layer and depletion of MREE in deeper layer were shown in porewater profile. This study suggests that porewater flux in the western Pacific basin is a minor source of REEs to seawater, and abundant REEs are enriched in sediments, which is mainly caused by the extensive oxic condition, low sedimentation rate and strong adsorption capacity of sediments. Hence, the removal of REEs of porewater may result in widespread REE-rich sediments in the western Pacific basin.

Selective Recovery of Yttrium and Ytterbium Oxides from Abu Rusheid REEs Concentrate via Alkaline Leaching and Solvent Extraction

International Nuclear Information System (INIS)

El-Sheikh, E.M.

2017-01-01

The REEs concentrate prepared from Abu Rusheid lamprophyre ore material is found to assay 44.65% Y_2O_3 and 13.87% Yb_2O_3 together with less amounts of 10 other REEs. This concentrate has been subjected to alkaline leaching process using seven different alkali reagents (single or mixed). From the obtained results, the mixed Na_2CO_3/(NH_4)HCO_3 reagent has been able to leach up to 87.32 % of Yb and 98.73% of Y together with a minor amount of Eu( 1.44)%. Finally, TBP extractant has been used to separate highly pure Yb and Y concentrate oxides from the nitrate solution

Geochemistry of U-Th- REE bearing minerals, in radioactive pegmatite in Um Swassi-Dara area, north eastern desert, Egypt

International Nuclear Information System (INIS)

Ali, B. H.

2007-01-01

Some of the pegmatites in the north Eastern Desert of Egypt have high radioactive values, between them the studied radioactive pegmatites which are clustered just in the western margin of Um Swassi-Dara hosted monzogranites. In zoned pegmatite the alteration zones locate between quartz core and intermediate zone are characterizing with the abundance of rare-earth minerals, anderbergite, cenosite, Y-allanite and uranium, thorium minerals such as euxenite, ferro-columbite and complex titanium-yetrum oxides (Kobbite). This zone is a result of many alteration processes developed from volatile-rich magmatic fluids and/or hydrothermal solution which evolved from late differentiated magmatic fluid and lead to increase of U, Th, Zr, Nb, Ti and REE bearing minerals. Such a distinctive alkaline mineralization suite, possibly related to an alkali fluid phase, is superimposed on a more normal, less alkaline group of minerals such as cassiterite, chalcopyrite, and galena. Nb-Ta-Ti minerals bearing U and Th, define a sequence of oxide, cyclosilicate and silicate minerals, showing the effect of hydrothermal overprinting with extreme REE enrichment of the fluids. It can be concluded that the studied mineralization took place in three overlapping stages

Leaching Kinetics of Praseodymium in Sulfuric Acid of Rare Earth Elements (REE) Slag Concentrated by Pyrometallurgy from Magnetite Ore

International Nuclear Information System (INIS)

Kim, Chul-Joo; Yoon, Ho-Sung; Chung, Kyung Woo; Lee, Jin-Young; Kim, Sung-Don; Shin, Shun Myung; Kim, Hyung-Seop; Cho, Jong-Tae; Kim, Ji-Hye; Lee, Eun-Ji; Lee, Se-Il; Yoo, Seung-Joon

2015-01-01

A leaching kinetics was conducted for the purpose of recovery of praseodymium in sulfuric acid (H 2 SO 4 ) from REE slag concentrated by the smelting reduction process in an arc furnace as a reactant. The concentration of H 2 SO 4 was fixed at an excess ratio under the condition of slurry density of 1.500 g slag/L, 0.3 mol H 2 SO 4 , and the effect of temperatures was investigated under the condition of 30 to 80 .deg. C. As a result, praseodymium oxide (Pr 6 O 1 1) existing in the slag was completely converted into praseodymium sulfate (Pr 2 (SO 4 ) 3 ·8H 2 O) after the leaching of 5 h. On the basis of the shrinking core model with a shape of sphere, the first leaching reaction was determined by chemical reaction mechanism. Generally, the solubility of pure REEs decreases with the increase of leaching temperatures in sulfuric acid, but REE slag was oppositely increased with increasing temperatures. It occurs because the ash layer included in the slag is affected as a resistance against the leaching. By using the Arrhenius expression, the apparent activation energy of the first chemical reaction was determined to be 9.195 kJmol -1 . In the second stage, the leaching rate is determined by the ash layer diffusion mechanism. The apparent activation energy of the second ash layer diffusion was determined to be 19.106 kJmol -1 . These relative low activation energy values were obtained by the existence of unreacted ash layer in the REE slag

Aqueous Rare Earth Element Patterns and Concentration in Thermal Brines Associated With Oil and Gas Production

Energy Technology Data Exchange (ETDEWEB)

Nye, Charles [University of Wyoming; Quillinan, Scott Austin [University of Wyoming; Neupane, Ghanashyam [Idaho National Lab. (INL), Idaho Falls, ID (United States); McLing, Travis [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2017-02-13

This study is part of a joint effort by the University of Wyoming (UW) School of Energy Resources (SER), the UW Engineering Department, Idaho National Laboratories (INL), and the United States Geological Survey (USGS) to describe rare earth element concentrations in oil and gas produced waters and in coal-fired power station ash ponds. In this work we present rare earth element (REE) and trace metal behavior in produced water from four Wyoming oil and gas fields and surface ash pond water from two coal-fired power stations. The concentration of REEs in oil and gas produced waters is largely unknown. For example, of the 150,000 entries in the USGS National Produced Waters Geochemical Database less than 5 include data for REEs. Part of the reason for this scarcity is the analytical challenge of measuring REEs in high salinity, hydrocarbon-bearing waters. The industry standard for water analysis struggles to detect REEs in natural waters under ideal conditions. The detection of REEs in oil and gas field samples becomes all but impossible with the background noise and interferences caused by high concentrations of non-REE ions and residual hydrocarbons. The INL team members have overcome many of these challenges (e.g. McLing, 2014), and continue to develop their methods. Using the methods of the INL team members we measured REEs in high salinity oil and gas produced waters. Our results show that REEs exist as a dissolved species in all waters measured for this project, typically within the parts per trillion range. The samples may be grouped into two broad categories analytically, and these categories match their genesis: Wyoming oil and gas brines contain elevated levels of Europium, and Wyoming industrial pond waters show elevation in heavy REEs (HREEs). While broadly true, important variations exist within both groups. In the same field Europium can vary by more than an order of magnitude, and likewise HREEs in industrial ponds at the same site can vary by more than

Uranium, thorium and rare earth elements distribution from different iron quadrangle spring waters

International Nuclear Information System (INIS)

Ferreira, Cláudia A.; Palmieri, Helena E.L.; Menezes, Maria A. de B.C.; Rodrigues, Paulo C.H.

2017-01-01

This study was conducted to evaluate the concentrations of thorium, uranium and the rare earth elements (REE) in 26 spring waters, as well as the patterns of the REE of the samples from the Cercadinho, Moeda and Caue aquifers in different municipalities of the Iron Quadrangle (Quadrilatero Ferrifero), located in the central-southeast of Minas Gerais state. The pH value of the ground waters ranged from 3.8 to 7.0, indicating an acid nature of most of the spring waters. The investigation of REE speciation showed that all the REEs exist in the free X"3"+ ionic forms, under the prevailing Eh and pH conditions. In the studied samples the uranium concentrations ( 1000 ng L"-"1) originating from aquifers located in Sabara, Barao de Cocais, Santa Barbara, Mario Campos, Congonhas and Lavras Novas. The REEs patterns in the spring waters from the Cercadinho, Caue and Moeda aquifers are characterized by middle REE (MREE) enrichment compared to light REE (LREE) and heavy REEs (HREE), negative Ce anomalies (except for one sample) and positive Eu anomalies in all three aquifers studied. (author)

Naturally Occurring Radionuclides and Rare Earth Elements Pattern in Weathered Japanese Soil Samples

International Nuclear Information System (INIS)

Sahoo, S.K.; Hosoda, M.; Takahashi, H.; Sorimachi, A.; Ishikawa, T.; Tokonami, S.; Uchida, S.

2011-01-01

From the viewpoint of radiation protection, determination of natural radionuclides e.g. thorium and uranium in soil samples are important. Accurate methods for determination of Th and U is gaining importance. The geochemical behavior of Th, U and rare earth elements (REEs) are relatively close to one another while compared to other elements in geological environment. Radioactive elements like 232 Th and 238 U along with their decay products (e.g. 226 Ra) are present in most of the environmental matrices and can be transferred to living bodies by different pathways that can lead to sources of exposure of man. Therefore, it is necessary to monitor these natural radionuclides in weathered soil samples to assess the possible hazards. The activity concentrations of 226 Ra, 228 Th, and 40 K in soils have been measured using a g γ-ray spectroscopy system with high purity germanium detector. The thorium, uranium and REEs were determined from the same sample using inductively coupled plasma mass spectrometry (ICP-MS). Granitic rocks contain higher amounts of Th, U and light REEs compared to other igneous rocks such as basalt and andesites. Therefore, it is necessary to understand the interaction between REEs and nature of soils, as soils are complex heterogeneous mixture of organic and inorganic solids, water and gases. In this paper, we have discussed about distribution pattern of 226 Ra, 232 Th and 238 U along with REEs in soil samples of weathered acid rock (granite and ryolite) collected from two prefectures in Japan: 1. Gifu and 2. Okinawa. (author)

Rare Earth Element Concentrations and Fractionation Patterns Along Groundwater Flow Paths in Two Different Aquifer Types (i.e., Sand vs. Carbonate)

Science.gov (United States)

Johannesson, K. H.; Tang, J.

2003-12-01

increase along groundwater flow path, however, MREE (Gd) exhibit little change and HREE (Yb) concentrations tend to decreases along the flow path. Floridan groundwaters have HREE enriched shale-normalized patterns, although (Yb/Nd)SN values decrease along groundwater flow path. Thus, REE patterns of Floridan groundwaters tend to flatten with flow down-gradient. All groundwaters show positive Eu anomalies (0.06 - 0.17) and negative Ce anomalies (-0.12 - -0.63).

Leaching Kinetics of Praseodymium in Sulfuric Acid of Rare Earth Elements (REE) Slag Concentrated by Pyrometallurgy from Magnetite Ore

Energy Technology Data Exchange (ETDEWEB)

Kim, Chul-Joo; Yoon, Ho-Sung; Chung, Kyung Woo; Lee, Jin-Young; Kim, Sung-Don; Shin, Shun Myung [Korea Institute of Geoscience and Mineral Resources, Daejeon (Korea, Republic of); Kim, Hyung-Seop; Cho, Jong-Tae; Kim, Ji-Hye; Lee, Eun-Ji; Lee, Se-Il; Yoo, Seung-Joon [Seonam University, Asan (Korea, Republic of)

2015-02-15

A leaching kinetics was conducted for the purpose of recovery of praseodymium in sulfuric acid (H{sub 2}SO{sub 4}) from REE slag concentrated by the smelting reduction process in an arc furnace as a reactant. The concentration of H{sub 2}SO{sub 4} was fixed at an excess ratio under the condition of slurry density of 1.500 g slag/L, 0.3 mol H{sub 2}SO{sub 4}, and the effect of temperatures was investigated under the condition of 30 to 80 .deg. C. As a result, praseodymium oxide (Pr{sub 6}O{sub 1}1) existing in the slag was completely converted into praseodymium sulfate (Pr{sub 2}(SO{sub 4}){sub 3}·8H{sub 2}O) after the leaching of 5 h. On the basis of the shrinking core model with a shape of sphere, the first leaching reaction was determined by chemical reaction mechanism. Generally, the solubility of pure REEs decreases with the increase of leaching temperatures in sulfuric acid, but REE slag was oppositely increased with increasing temperatures. It occurs because the ash layer included in the slag is affected as a resistance against the leaching. By using the Arrhenius expression, the apparent activation energy of the first chemical reaction was determined to be 9.195 kJmol{sup -1}. In the second stage, the leaching rate is determined by the ash layer diffusion mechanism. The apparent activation energy of the second ash layer diffusion was determined to be 19.106 kJmol{sup -1}. These relative low activation energy values were obtained by the existence of unreacted ash layer in the REE slag.

Grow your own REE deposits: Novel observations from the soils of Southern Portugal

Science.gov (United States)

Hardy, Liam; Smith, Martin; Boyce, Adrian; McDonald, Alison; Heller, Shaun; Bamberger, Axel; Blum, Astrid; Hood, Leo

2017-04-01

Industrialised eucalyptus farming in Serra de Monchique has been well documented for its regional impacts on water flow, for its destructive centralisation of local economics (Jenkins, 1979) and for its derogatory impacts on local ecology (Brito, 1999) (Matias & Lamberts, 2011), it is another story of cash cropping for short term gain in an area of sensitive environmental balance which had previously been suitably subsistence farmed for some 700 years with no outside influence until the early 1950s (Jenkins, 1979). The farming has irreversibly changed local customs, soil and water systems, but formed new and intricate relationships between the troposol, oxisol and latosol formations and plants which have not previously been studied in this region in terms of soil geochemistry. During research in the region (as part of the SoS Rare/NERC-UK program) into metal and clay interactions in the troposol formations of Monchique, it was noted that rare earth elements (REEs) and other soluble ions were being mobilised in the upper half of the profiles by some seasonal cycle other than the natural meteoric input/leaching expected during classical lateritisation (Tardy, 1997). It was observed that some 40% of Fe and some 30% of Y were leaving the profile during wet season and concentrating at specific depths during dry seasons to a grade of some 160ppm Y and were thus, potentially viable as an economic resource of Heavy REEs. This PICO presentation discusses the proposed anthropogenic/biogenic mechanism for this concentration and how you too could potentially grow an economically viable REE enriched garden. References: Brito, J. G. (1999). Management strategies for conservation of the lizard Lacerta schreiberi in Portugal. Biological conservation, 311-319. Jenkins, R. (1979). The Road to Alto: An account of peasants, capitalists and their soil in the mountains of Southern Portugal. London: Pluto, ISBN: 0861040767. Matias, M., & Lamberts, P. (2011, May 26). Parliamentary

Rare earth and trace elements of fossil vertebrate bioapatite as palaeoenvironmental and sedimentological proxies

Science.gov (United States)

Žigaitė, Živilė; Fadel, Alexandre; Pérez-Huerta, Alberto; Jeffries, Teresa

2015-04-01

Rare earth (REE) and trace element compositions of fossil vertebrate dental microremains have been studied in Silurian and Devonian vertebrate dental scales and spines in-situ, using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Samples were selected from the well-known Silurian bone beds of Vesiku and Ohesaare in Saaremaa island of Estonia, and a number of Lower Devonian localities from Spitsbergen (Svalbard), Andrée Land group. Biomineral preservation was assessed using spot semi-quantitative elemental chemistry (SEM-EDS) and electron back-scatter difractometry (EBSD) for cristallinity imaging. The obtained PAAS shale-normalised REE concentrations were evaluated using basic geochemical calculations and quantifications. The REE patterns from the Lower Devonian vertebrate apatite from Andrée Land, Spitsbergen (Wood Bay and Grey Hœk formations) did not show any recognisable taxon-specific behavior, but had rather well expressed differences of REE compositions related to biomineral structure and sedimentary settings, suggesting REE instead to reflect burial environments and sedimentological history. The Eu anomaly recorded in two of the studied localities but not in the other indicate different taphonomic conditions and palaeoenvironment, while La/Sm, La/Yb ratios sugeest considerable influence of terrestrial freshwater during the early diagenesis. The La/Yb and La/Sm plots also agree with the average REE concentrations, reflecting domination of the adsoption over substitution as principal REE uptake mechanism in the fossils which had significantly lower overall REE concentrations, and vice versa. Vesiku (Homerian, Wenlock) microremains yielded very uniform REE patterns with slightly lower overall REE concentrations in enameloid than in dentine, with strong enrichment in middle REE and depletion in heavy REE. Negative Europium (Eu) anomaly was pronounced in all the profiles, but Cerium (Ce) anomalies were not detected suggesting possible

Spectral response of REE{sup 3+} doped LaAlO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Boronat, C.; Correcher, V. [CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); Garcia G, J. [Museo Nacional de Ciencias Naturales - Consejo Superior de Investigaciones Cientificas, 28006 Madrid (Spain); Morales, A.; Zarate, J. [Universidad Michoacana de San Nicolas de Hidaldo, Instituto de Investigacion en Metalurgia y Materiales, Ciudad Universitaria, Morelia, Michoacan (Mexico); Rivera, T., E-mail: Cecilia.Boronat@ciemat.es [IPN, Ciudad de Mexico (Mexico)

2016-10-15

This paper reports on the preliminary results obtained from the cathodoluminescence (Cl) and thermoluminescence (Tl) properties of undoped LaAlO{sub 3} (LAO) and LaAlO{sub 3}: REE (REE=Dy{sup 3+}, Pr{sup 3+} and Eu{sup 3+}) to be potentially employed for dosimetric purposes. The samples were synthesized by a sol-gel process based on the Pechini 's method with a spray-drying technique and, subsequently, characterized by environmental scanning electron microscopy and energy dispersive X-ray analysis spectrometry. Cl spectra display sharp and narrow wavebands that could specifically be associated with structural (in the range of 300-450 nm) and point defects (from 450 to 800 nm). The observed wavebands could be assigned as follows: (i) 480 and 570 from the Dy-doped LAO should corresponding respectively to {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2} and {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} transitions, (II) 490-638 from the Pr-doped LAO is linked to {sup 3}P{sub 0}→{sup 3}H{sub 4}, {sup 1}D{sub 2}→{sup 3}H{sub 4} transitions and (III) 590 and 620 where the dopant Eu{sup 3+} gives rise to {sup 5}D{sub 0}→{sup 7}F{sub 1} and {sup 5}D{sub 0}→{sup 7}F{sub 2} transitions and (IV) a UV-blue broad band is associated with NBOHC in undoped LAO. Such emissions are due to the presence of the 4f electrons of rare earth ions that are shielded by the outer 5s and 5p electrons, the intra-4f emission spectra of REE. Furthermore, the study performed on the Tl emission of LaAlO{sub 3}:Dy{sup 3+} displays (i) two maxima centred at 150 and 240 degrees Celsius (ratio 1:2) similarly to the Pr{sup 3+} doped sample but with 7:5 of ratio. And (II) the highest radiation sensitivity, allowing us to think on the potential use of this material for dosimetric purposes, however further works are necessary to confirm such assertion. (Author)

Light Rare Earth Elements enrichment in an acidic mine lake (Lusatia, Germany)

International Nuclear Information System (INIS)

Bozau, Elke; Leblanc, Marc; Seidel, Jean Luc; Staerk, Hans-Joachim

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 SO 4 -rich lake water (pH 2.7) displays high REE contents (e.g. La∼70 μg/l, Ce∼160 μg/l) and an enrichment of light REE (LREE) in the NASC normalised pattern. Considering the hydrodynamic model and geochemical data, the lake water composition may be calculated as a mixture of inflowing Quaternary and mining dump groundwaters. The groundwater of the dump aquifer is LREE enriched. Nevertheless, the leachates of dump sediments generally have low REE contents and display flat NASC normalised patterns. However, geochemical differences and REE pattern in undisturbed lignite (LREE enriched pattern and low water soluble REE contents) and the weathered lignite of the dumps (flat REE pattern and high water soluble REE contents) suggest that lignite is probably the main REE source rock for the lake water

Investigation of the weathering effect on Rb-Sr systematics and trace element abundances in Antarctic and non-Antarctic meteorites

International Nuclear Information System (INIS)

Nishikawa, Yoshiyuki; Nakamura, Noboru; Misawa, Keiji; Okano, Osamu; Yamamoto, Koshi; Kagami, Hiroo.

1990-01-01

In order to examine weathering effects on chondritic meteorites in Antarctic and non-Antarctic environments, the Rb-Sr isotopic ratios and abundances of REE, Ba, Sr, Rb, and K were determined for 8H-group chondrites (Yamato-790986 [H3], Yamato-74492 [H3], Grady [H3], Brownfield [H3], Clovis (No.1) [H3], Yamato-74155 [H4], Allegan [H5] [one whole-rock and two chondrules], and Yamato-74371 [H5]), and partly for the Etter (L5) chondrite. The Allegan whole-rock shows a flat REE pattern with a large negative Eu anomaly and Sr depletion. Analyses of Rb-Sr systematics of one whole-rock and two chondrules show somewhat younger age 4.38±0.12 b.y. It is suggested that REE and Rb-Sr were redistributed during the early thermal metamorphism. Except for Allegan, most other H-chondrites (finds) show the perturbation of the Rb-Sr systematics, indicating recent loss of Rb. It was found that the weathering degree is related with the Rb-Sr disturbance in Antarctic H-chondrite. In spite of different degrees of weathering, all the Antarctic H-chondrites studied (including heavily weathered ones) show flat REE patterns normal as H-chondrite with occasional occurrence of minor Eu anomalies, indicating the tough resistance of REE in H-chondrites to the Antarctic weathering. On the other hand, non-Antarctic finds (particularly the weathered chondrites) indicate light-REE enriched patterns with a large negative Ce anomaly and extreme enrichment of Ba, suggestive of terrestrial contaminations. (author)

Rare Earth Elements (REE Deposits Associated with Great Plain Margin Deposits (Alkaline-Related, Southwestern United States and Eastern Mexico

Directory of Open Access Journals (Sweden)

Virginia T. McLemore

2018-01-01

Full Text Available W.G. Lindgren in 1933 first noted that a belt of alkaline-igneous rocks extends along the eastern edge of the Rocky Mountains and Basin and Range provinces from Alaska and British Columbia southward into New Mexico, Trans-Pecos Texas, and eastern Mexico and that these rocks contain relatively large quantities of important commodities such as, gold, fluorine, zirconium, rare earth elements (REE, tellurium, gallium, and other critical elements. In New Mexico, these deposits were called Great Plain Margin (GPM deposits, because this north-south belt of alkaline-igneous rocks roughly coincides with crustal thickening along the margin between the Great Plains physiographic province with the Basin and Range (including the Rio Grande rift and Rocky Mountains physiographic provinces, which extends into Trans-Pecos Texas and eastern Mexico. Since 1996, only minor exploration and development of these deposits in New Mexico, Texas, and eastern Mexico has occurred because of low commodity prices, permitting issues, and environmental concerns. However, as the current demand for gold and critical elements, such as REE and tellurium has increased, new exploration programs have encouraged additional research on the geology of these deposits. The lack of abundant quartz in these systems results in these deposits being less resistant to erosion, being covered, and not as well exposed as other types of quartz-rich deposits, therefore additional undiscovered alkaline-related gold and REE deposits are likely in these areas. Deposits of Th-REE-fluorite (±U, Nb epithermal veins and breccias are found in the several GPM districts, but typically do not contain significant gold, although trace amounts of gold are found in most GPM districts. Gold-rich deposits in these districts tend to have moderate to low REE and anomalously high tungsten and sporadic amounts of tellurium. Carbonatites are only found in New Mexico and Mexico. The diversity of igneous rocks, including

Oil-refinery and automotive emissions of rare earth elements

International Nuclear Information System (INIS)

Kitto, M.E.; Gordon, G.E.; Anderson, D.L.; Olmez, I.

1991-01-01

The concentration pattern of rare-earth elements (REEs) in emissions from oil refineries and newer-model automobiles shows a distortion from the crustal abundance pattern. The REEs arise from the zeolite cracking catalysts used in petroleum refining and emission-control substrates used in automobile catalytic converters, respectively. Ten petroleum cracking catalysts from four countries and 12 catalytic converters from five automobile manufacturers were characterized for their REE content. The cracking catalysts are highly enriched in light REEs, whereas the automobile catalysts are enriched primarily in Ce. Incorporation of zeolite catalysts into refined oil provides new atmospheric elemental signatures for tracing emissions from refineries and oil-fired power plants on a regional scale. Though both have enhanced La/REE ratios, emissions from these two sources can be distinguished by their La/V ratios. Although REE demand by the petroleum industry has dropped considerably in recent years, automobile catalytic converters containing REEs are expected to increase dramatically as more stringent emission regulations are adopted in Europe, Japan and the US

Carbonatites in China: A review for genesis and mineralization

Directory of Open Access Journals (Sweden)

Cheng Xu

2010-10-01

Full Text Available Carbonatites are commonly related to the accumulation of economically valuable substances such as REE, Cu, and P. The debate over the origin of carbonatites and their relationship to associated silicate rocks has been ongoing for about 45 years. Worldwide, the rocks characteristically display more geochemical enrichments in Ba, Sr and REE than sedimentary carbonate rocks. However, carbonatite’s geochemical features are disputed because of secondary mineral effects. Rock-forming carbonates from carbonatites at Qinling, Panxi region, and Bayan Obo in China show REE distribution patterns ranging from LREE enrichment to flat patterns. They are characterized by a Sr content more than 10 times higher than that of secondary carbonates. The coarse- and fine-grained dolomites from Bayan Obo H8 dolomite marbles also show similar high Sr abundance, indicating that they are of igneous origin. Some carbonates in Chinese carbonatites show REE (especially HREE contents and distribution patterns similar to those of the whole rocks. These intrusive carbonatites display lower platinum group elements and stronger fractionation between Pt and Ir relative to high-Si extrusive carbonatite. This indicates that most intrusive carbonatites may be carbonate cumulates. Maoniuping and Daluxiang in Panxi region are large REE deposits. Hydrothermal fluorite ore veins occur outside of the carbonatite bodies and are emplaced in wallrock syenite. The fluorite in Maoniuping has Sr and Nd isotopes similar to carbonatite. The Daluxiang fluorite shows Sr and REE compositions different from those in Maoniuping. The difference is reflected by both the carbonatites and rock-forming carbonates, indicating that REE mineralization is related to carbonatites. The cumulate processes of carbonate minerals make fractionated fluids rich in volatiles and LREE as a result of low partition coefficients for REE between carbonate and carbonatite melt and an increase from LREE to HREE. The

The formation and trace elements of garnet in the skarn zone from the Xinqiao Cu-S-Fe-Au deposit, Tongling ore district, Anhui Province, Eastern China

Science.gov (United States)

Xiao, Xin; Zhou, Tao-fa; White, Noel C.; Zhang, Le-jun; Fan, Yu; Wang, Fang-yue; Chen, Xue-feng

2018-03-01

Xinqiao is a large copper-gold deposit and consists of two major mineralization types: stratabound and skarn. The skarn occurs along the contact between a quartz diorite intrusion and Carboniferous-Triassic limestone. Xinqiao has a strongly developed skarn zone, including endoskarn and exoskarn; the exoskarn is divided into proximal and distal exoskarn. We present systematic major, trace and rare earth element (REE) concentrations for garnets from the skarn zone, discuss the factors controlling the incorporation of trace elements into the garnets, and constrain the formation and evolution of the garnet from skarn zone in Xinqiao deposit. Grossular (Adr20-44Grs56-80) mostly occurs in endoskarn and has typical HREE-enriched and LREE-depleted patterns, with small Eu anomalies and low ∑REE. Garnets from the exoskarn show complex textures and chemical compositions. The composition of garnets range from Al-rich andradite (Adr63-81Grs19-47) to andradite (Adr67-98Grs2-33). Garnet in endoskarn has typical HREE-enriched and LREE-depleted patterns. Al-rich andradite in proximal skarn has small Eu anomalies and moderate ∑REE. Andradite from distal exoskarn shows strong positive Eu anomalies and has variable ∑REE. The U, Y, Fe and Al relationship with ∑REE shows that two mechanisms controlled incorporation of REE into the garnets: crystal chemistry (substitution and interstitial solid solution) mainly controlled in the endoskarn garnet (grossular) and the proximal exoskarn (Al-rich andradite), and fluid and rock chemistry (surface adsorption and occlusion) controlled REEs in the distal exoskarn. Furthermore, Al has a negative relationship with ∑REE indicating that REE3+ did not follow a coupled, YAG-type substitution into the garnets. Variations in textures and trace and rare earth elements of garnets suggest that the garnets in the endoskarn formed by slow crystal growth at low W/R ratios and near-neutral pH in a closed system during periods of diffusive metasomatism

Rare earth element geochemistry of oceanic ferromanganese nodules and associated sediments

Science.gov (United States)

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

1981-04-01

Analyses have been made of REE contents of a well-characterized suite of deep-sea (> 4000 m.) principally todorokite-bearing ferromanganese nodules and associated sediments from the Pacific Ocean. REE in nodules and their sediments are closely related: nodules with the largest positive Ce anomalies are found on sediments with the smallest negative Ce anomalies; in contrast, nodules with the highest contents of other rare earths (3 + REE) are found on sediments with the lowest 3 + REE contents and vice versa. 143Nd /144Nd ratios in the nodules (˜0.51244) point to an original seawater source but an identical ratio for sediments in combination with the REE patterns suggests that diagenetic reactions may transfer elements into the nodules. Analysis of biogenic phases shows that the direct contribution of plankton and carbonate and siliceous skeletal materials to REE contents of nodules and sediments is negligible. Inter-element relationships and leaching tests suggest that REE contents are controlled by a P-rich phase with a REE pattern similar to that for biogenous apatite and an Fe-rich phase with a pattern the mirror image of that for sea water. It is proposed that 3 + REE concentrations are controlled by the surface chemistry of these phases during diagenetic reactions which vary with sediment accumulation rate. Processes which favour the enrichment of transition metals in equatorial Pacific nodules favour the depletion of 3 + REE in nodules and enrichment of 3 + REE in associated sediments. In contrast, Ce appears to be added both to nodules and sediments directly from seawater and is not involved in diagenetic reactions.

REE in suspended particulate matter and sediment of the Zuari estuary and adjacent shelf, western India: Influence of mining and estuarine turbidity

Digital Repository Service at National Institute of Oceanography (India)

Shynu, R.; Rao, V.P.; Parthiban, G.; Balakrishnan, S.; Narvekar, T.; Kessarkar, P.M.

in the development of ETM in the lower estuary (Rao et al., 2011). As a consequence bottom sediment may have been re-suspended, thereby increasing SPM and REE in the water column and mixed up with the sediment brought by the river. In other words, the REE.... Seminar Volume on Earth Resources for Goa’s Development. Geological Survey of India, pp. 1-13. Goldstein, S.J., Jacobsen, S.B., 1988. Rare earth elements in river waters. Earth Planetary Science Letters 89, 35-47. Govindaraju, K., 1994. Compilation...

Origin of convex tetrads in rare earth element patterns of hydrothermally altered siliceous igneous rocks from the Zinnwald Sn–W deposit, Germany

OpenAIRE

T. Monecke; Peter Dulski; U. Kempe

2007-01-01

The chondrite-normalized rare earth element (REE) patterns of whole rock samples from evolved granitic systems hosting rare metal deposits sometimes show a split into four consecutive curved segments, referred to as tetrads. In the present contribution, a rigorous statistical method is proposed that can be used to test whether geological significance should be attributed to tetrads that are only of limited size. The method involves a detailed evaluation of element and sample specific random a...

Rare earth elements in freshwater, marine, and terrestrial ecosystems in the eastern Canadian Arctic.

Science.gov (United States)

MacMillan, Gwyneth Anne; Chételat, John; Heath, Joel P; Mickpegak, Raymond; Amyot, Marc

2017-10-18

Few ecotoxicological studies exist for rare earth elements (REEs), particularly field-based studies on their bioaccumulation and food web dynamics. REE mining has led to significant environmental impacts in several countries (China, Brazil, U.S.), yet little is known about the fate and transport of these contaminants of emerging concern. Northern ecosystems are potentially vulnerable to REE enrichment from prospective mining projects at high latitudes. To understand how REEs behave in remote northern food webs, we measured REE concentrations and carbon and nitrogen stable isotope ratios (∂ 15 N, ∂ 13 C) in biota from marine, freshwater, and terrestrial ecosystems of the eastern Canadian Arctic (N = 339). Wildlife harvesting and tissue sampling was partly conducted by local hunters through a community-based monitoring project. Results show that REEs generally follow a coherent bioaccumulation pattern for sample tissues, with some anomalies for redox-sensitive elements (Ce, Eu). Highest REE concentrations were found at low trophic levels, especially in vegetation and aquatic invertebrates. Terrestrial herbivores, ringed seal, and fish had low total REE levels in muscle tissue (∑REE for 15 elements <0.1 nmol g -1 ), yet accumulation was an order of magnitude higher in liver tissues. Age- and length-dependent REE accumulation also suggest that REE uptake is faster than elimination for some species. Overall, REE bioaccumulation patterns appear to be species- and tissue-specific, with limited potential for biomagnification. This study provides novel data on the behaviour of REEs in ecosystems and will be useful for environmental impact assessment of REE enrichment in northern regions.

Formation of fast-spreading lower oceanic crust as revealed by a new Mg-REE coupled geospeedometer

Science.gov (United States)

Sun, Chenguang; Lissenberg, C. Johan

2018-04-01

A new geospeedometer is developed based on the differential closures of Mg and rare earth element (REE) bulk-diffusion between coexisting plagioclase and clinopyroxene. By coupling the two elements with distinct bulk closure temperatures, this speedometer can numerically solve the initial temperatures and cooling rates for individual rock samples. As the existing Mg-exchange thermometer was calibrated for a narrow temperature range and strongly relies on model-dependent silica activities, a new thermometer is developed using literature experimental data. When the bulk closure temperatures of Mg and REE are determined, respectively, using this new Mg-exchange thermometer and the existing REE-exchange thermometer, this speedometer can be implemented for a wide range of compositions, mineral modes, and grain sizes. Applications of this new geospeedometer to oceanic gabbros from the fast-spreading East Pacific Rise at Hess Deep reveal that the lower oceanic crust crystallized at temperatures of 998-1353 °C with cooling rates of 0.003-10.2 °C/yr. Stratigraphic variations of the cooling rates and crystallization temperatures support deep hydrothermal circulations and in situ solidification of various replenished magma bodies. Together with existing petrological, geochemical and geophysical evidence, results from this new speedometry suggest that the lower crust formation at fast-spreading mid-ocean ridges involves emplacement of primary mantle melts in the deep section of the crystal mush zone coupled with efficient heat removal by crustal-scale hydrothermal circulations. The replenished melts become chemically and thermally evolved, accumulate as small magma bodies at various depths, feed the shallow axial magma chamber, and may also escape from the mush zone to generate off-axial magma lenses.

The emplacement and crystallization of the U-Th-REE-rich agpaitic and hyperagpaitic lujavrites at Kvanefjeld, Ilimaussaq alkaline complex, South Greenland

International Nuclear Information System (INIS)

Soerensen, H.; Bailey, J.C.; Rose-Hansen, J.

2011-01-01

The U-Th-REE deposit located at the Kvanefjeld plateau in the north-west corner of the Ilimaussaq alkaline complex, South Greenland, consists of lujavrites which are melanocratic agpaitic nepheline syenites. The fine-grained lujavrites of the Kvanefjeld plateau can be divided into a northern and a southern part with an intermediate zone between them. The northern part is situated along the north contact of the Ilimaussaq complex and continues east of the Kvanefjeld plateau as a lujavrite belt along the contact. This part has relatively 'low' contents of U, Th, and REE, and hyperagpaitic mineralogy is restricted to its highest-lying parts. The fine-grained lujavrites of the intermediate and southern part of the Kvanefjeld plateau occur between and below huge masses of country rocks which we show are practically in situ remnants of the roof of the lujavrite magma chamber. These lujavrites have high contents of U, Th, and REE, and hyperagpaitic varieties with naujakasite, steenstrupine and villiaumite are widespread. We present a model for the formation of the fine-grained lujavrites of the Kvanefjeld plateau. In this model, an off-shoot from the large lujavrite magma body in the central part of the complex intruded into a fracture zone along the north contact of the Ilimaussaq complex and was forcefully emplaced from north-west to south-east. The intruding lujavrite magma was bounded to the west, north, and at its roof by strong volcanic country rocks, and to the south by the weaker, earlier rocks of the complex. The magma stored in the fracture crystallized, squeezing volatile and residual ele-ments upwards. A subsequent violent explosion opened up fractures in the weaker southern rocks, and the residual volatile-enriched magma was squeezed into fractures in augite syenite, naujaite, and also in the overlying volcanic roof rocks. The removal of the volatile-rich lujavrite magma in the upper part of the fracture-bounded magma chamber made room for the rise of

Geochemical characteristics of dissolved rare earth elements in acid mine drainage from abandoned high-As coal mining area, southwestern China.

Science.gov (United States)

Li, Xuexian; Wu, Pan

2017-09-01

Acid mine drainage (AMD) represents a major source of water pollution in the small watershed of Xingren coalfield in southwestern Guizhou Province. A detailed geochemical study was performed to investigate the origin, distribution, and migration of REEs by determining the concentrations of REEs and major solutes in AMD samples, concentrations of REEs in coal, bedrocks, and sediment samples, and modeling REEs aqueous species. The results highlighted that all water samples collected in the mining area are identified as low pH, high concentrations of Fe, Al, SO 4 2- and distinctive As and REEs. The spatial distributions of REEs showed a peak in where it is nearby the location of discharging of AMD, and then decrease significantly with distance away from the mining areas. Lots of labile REEs have an origin of coal and bedrocks, whereas the acid produced by the oxidation of pyrite is a prerequisite to cause the dissolution of coal and bedrocks, and then promoting REEs release in AMD. The North American Shale Composite (NASC)-normalized REE patterns of coal and bedrocks are enriched in light REEs (LREEs) and middle REEs (MREEs) relative to heavy REEs (HREEs). Contrary to these solid samples, AMD samples showed slightly enrichment of MREEs compared with LREEs and HREEs. This behavior implied that REEs probably fractionate during acid leaching, dissolution of bedrocks, and subsequent transport, so that the MREEs is primarily enriched in AMD samples. Calculation of REEs inorganic species for AMD demonstrated that sulfate complexes (Ln(SO 4 ) + and Ln(SO 4 ) 2 - ) predominate in these species, accounting for most of proportions for the total REEs species. The high concentrations of dissolved SO 4 2- and low pH play a decisive role in controlling the presence of REEs in AMD, as these conditions are necessary for formation of stable REEs-sulfate complexes in current study. The migration and transportation of REEs in AMD are more likely constrained by adsorption and co

Comparison of the behaviour of rare earth elements in surface waters, overburden groundwaters and bedrock groundwaters in two granitoidic settings, Eastern Sweden

International Nuclear Information System (INIS)

Roennback, Pernilla; Astroem, Mats; Gustafsson, Jon-Petter

2008-01-01

This work, which was done within the Swedish nuclear waste management program, was carried out in order to increase the understanding of the mobility and fate of rare earth elements (REEs) in natural boreal waters in granitoidic terrain. Two areas were studied, Forsmark and Simpevarp, one of which will be selected as a site for spent nuclear fuel. The highest REE concentrations were found in the overburden groundwaters, in Simpevarp in particular (median ΣREE 52 μg/L), but also in Forsmark (median ΣREE 6.7 μg/L). The fractionation patterns in these waters were characterised by light REE (LREE) enrichment and negative Ce and Eu anomalies. In contrast, the surface waters had relatively low REE concentrations. They were characterised either by an increase in relative concentrations throughout the lanthanide series (Forsmark which has a carbonate-rich till) or flat patterns (Simpevarp with carbonate-poor till), and had negative Ce and Eu anomalies. In the bedrock groundwaters, the concentrations and fractionation patterns of REEs were entirely different from those in the overburden groundwaters. The median La concentrations were low (just above 0.1 μg/L in both areas), only in a few samples were the concentrations of several REEs (and in a couple of rare cases all REEs) above the detection limit, and there was an increase in the relative concentrations throughout the lanthanide series. In contrast to these large spatial variations, the temporal trends were characterised by small (or non existent) variations in REE-fractionation patterns but rather large variations in concentrations. The Visual MINTEQ speciation calculations predicted that all REEs in all waters were closely associated with dissolved organic matter, and not with carbonate. In the hydrochemical data for the overburden groundwater in particular, there was however a strong indication of association with inorganic colloids, which were not included in the speciation model. Overall the results showed

Determination of REE and U in agricultural soils from Jaguari River basin, Sao Paulo, by neutron activation analysis

International Nuclear Information System (INIS)

Ruby, E.C.; Modesto, R.P.; Lemos, M.M.G.

2009-01-01

Uranium has the highest atomic weight of the naturally occurring elements. It is weakly radioactive and occurs naturally in low concentrations (a few parts per million) in soil, rock and water. The rare earth elements (REE) form the largest chemically coherent group in the periodic table. The versatility and specificity of the REE have given them a level of technological, environmental, and economic importance considerably greater than might be expected. The objective of this work was to determine the concentration of the lanthanides (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu), and U, considering the soil use and occupation from the Jaguari river basin, Sao Paulo. Instrumental Neutron Activation Analysis (INAA) was used for the REE and U analysis The study area is located in a traditional agricultural area which is nowadays one of the main industrial regions of Brazil. In order to evaluate the quality of these soils in relation to lanthanides and U levels, the obtained concentrations were compared to guiding values reported by environmental protection agencies. The 75th percentile for U in agricultural soils (2.76 mg kg- 1 ) was higher than in the control areas (1.61 mg kg -1 ), but much lower than the maximum allowed concentration for soils in The Netherlands (28.3 mg kg -1 ). The lanthanides presented concentration levels higher than the guiding values of the RIVM - -National Institute for Public Health and the Environment guidelines. (author)

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

International Nuclear Information System (INIS)

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

2017-01-01

The recent commercialisation of inductively coupled plasma tandem mass spectrometric (ICP-MS/MS) instruments has provided analytical chemists with a new tool to properly quantify atomic composition in a variety of matrices with minimal sample preparation. In this article, we report on our assessment of the compatibility of 3 sample preparation techniques (open-vessel acid digestion, microwave digestion and alkaline fusion) for the quantification of rare earth elements (REEs) in mineral matrices. The combination of the high digestion temperatures (1050 °C) and using LiBO_2 as a flux was the most effective strategy for the digestion of all rare earth elements in mineral matrices and was compatible with ICP-MS/MS measurements. We also assessed the analytical performances of ICP-MS/MS against other plasma-based instrumentation (microwave induced plasma and inductively coupled plasma atomic emission spectroscopy (MIP-AES and ICP-AES, respectively) and single quadrupole inductively coupled plasma mass spectrometry (ICP-MS). The comparative study showed that the concentrations obtained by ICP-MS/MS are in excellent agreement with the certified reference material values, and much more suited than the other analytical techniques tested for the quantification of REEs, which exhibited low detectability and/or spectral interferences for some elements/isotopes. Finally, the ruggedness of the analytical protocol proposed which combines a rapid sample dissolution step performed by an automated fusion unit and an ICP-MS/MS as a detector was established using various certified mineral matrices containing variable levels of REEs. - Highlights: • Three types of digestion methods were tested. • Four types of analytical techniques were compared. • Elimination of the spectral interferences encountered in ICP-MS was achieved by the use of Tandem ICP-MS. • Robustness of the analytical procedure was successfully evaluate on four types of certified reference material.

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

Energy Technology Data Exchange (ETDEWEB)

Whitty-Léveillé, Laurence; Turgeon, Keven [Département de génie des mines, de la métallurgie et des matériaux, Université Laval, Québec, QC (Canada); Département de chimie, Université Laval, Québec, QC (Canada); Bazin, Claude [Département de génie des mines, de la métallurgie et des matériaux, Université Laval, Québec, QC (Canada); Larivière, Dominic, E-mail: dominic.lariviere@chm.ulaval.ca [Département de chimie, Université Laval, Québec, QC (Canada)

2017-04-08

The recent commercialisation of inductively coupled plasma tandem mass spectrometric (ICP-MS/MS) instruments has provided analytical chemists with a new tool to properly quantify atomic composition in a variety of matrices with minimal sample preparation. In this article, we report on our assessment of the compatibility of 3 sample preparation techniques (open-vessel acid digestion, microwave digestion and alkaline fusion) for the quantification of rare earth elements (REEs) in mineral matrices. The combination of the high digestion temperatures (1050 °C) and using LiBO{sub 2} as a flux was the most effective strategy for the digestion of all rare earth elements in mineral matrices and was compatible with ICP-MS/MS measurements. We also assessed the analytical performances of ICP-MS/MS against other plasma-based instrumentation (microwave induced plasma and inductively coupled plasma atomic emission spectroscopy (MIP-AES and ICP-AES, respectively) and single quadrupole inductively coupled plasma mass spectrometry (ICP-MS). The comparative study showed that the concentrations obtained by ICP-MS/MS are in excellent agreement with the certified reference material values, and much more suited than the other analytical techniques tested for the quantification of REEs, which exhibited low detectability and/or spectral interferences for some elements/isotopes. Finally, the ruggedness of the analytical protocol proposed which combines a rapid sample dissolution step performed by an automated fusion unit and an ICP-MS/MS as a detector was established using various certified mineral matrices containing variable levels of REEs. - Highlights: • Three types of digestion methods were tested. • Four types of analytical techniques were compared. • Elimination of the spectral interferences encountered in ICP-MS was achieved by the use of Tandem ICP-MS. • Robustness of the analytical procedure was successfully evaluate on four types of certified reference material.

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

Science.gov (United States)

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

1994-01-01

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

Patterned basal seismicity shows sub-ice stream bedforms

Science.gov (United States)

Barcheck, C. G.; Tulaczyk, S. M.; Schwartz, S. Y.

2017-12-01

Patterns in seismicity emanating from the bottom of fast-moving ice streams and glaciers may indicate localized patches of higher basal resistance— sometimes called 'sticky spots', or otherwise varying basal properties. These seismogenic basal areas resist an unknown portion of the total driving stress of the Whillans Ice Plain (WIP), in West Antarctica, but may play an important role in the WIP stick-slip cycle and ice stream slowdown. To better understand the mechanism and importance of basal seismicity beneath the WIP, we analyze seismic data collected by a small aperture (micro-earthquakes in Dec 2014, and we compare the resulting map of seismicity to ice bottom depth measured by airborne radar. The number of basal earthquakes per area within the network is spatially heterogeneous, but a pattern of two 400m wide streaks of high seismicity rates is evident, with >50-500 earthquakes detected per 50x50m grid cell in 2 weeks. These seismically active streaks are elongated approximately in the ice flow direction with a spacing of 750m. Independent airborne radar measurements of ice bottom depth from Jan 2013 show a low-amplitude ( 5m) undulation in the basal topography superposed on a regional gradient in ice bottom depth. The flow-perpendicular wavelength of these low-amplitude undulations is comparable to the spacing of the high seismicity bands, and the streaks of high seismicity intersect local lows in the undulating basal topography. We interpret these seismic and radar observations as showing seismically active sub-ice stream bedforms that are low amplitude and elongated in the direction of ice flow, comparable to the morphology of mega scale glacial lineations (MSGLs), with high basal seismicity rates observed in the MSGL troughs. These results have implications for understanding the formation mechanism of MSGLS and well as understanding the interplay between basal topographic roughness, spatially varying basal till and hydrologic properties, basal

Lithogeochemistry of rare-earth elements in the characterization of granitoids from the Cachoeirinha belt, Northeast Brazil

International Nuclear Information System (INIS)

Sial, A.N.

1984-01-01

Detailed rare-earth element study on about 40 samples from 14 granitic bodies distributed within and in adjacent areas of the Cachoeirinha belt, states of Pernambuco and Paraiba, between 37 0 and 40 0 W long. and 7 0 and 8 0 15' lat., was performed. These bodies include potassic, calc-alkalic, and peralkalic granitic associations, besides one with trondhjemitic affinities. The REE patterns for the potassic granitoids (Bodoco, Serra da Lagoinha and Itaporanga) which pierced basement migmatites, are strongly fractionated, mutually similar, LREE-enriched, and lack En anomaly. The calc-alkalic granitoids (Conceicao-type) intruded the low-grade metamorphics, and display strongly fractionated REE patterns, LREE-enriched relative to HREE, and exhibit a discrete, yet significative negative Eu anomaly. The granitoids with trondhjemitic affinities (Serrita-type) which intruded the Salgueiro schists, exhibit Σ REE much lower than in the previously mentioned granituids - REE patterns are strongly fractionated, LREE - enriched in relation to HREE, with discrete positive Eu anomaly and HREE approaching chondrite abundances. REE patterns of the peralkalic granitoids (Catingueira-type) ressemble those of rocks with trondhjemitic affinities and show a discrete positive Eu anomaly. The REE geochemistry agrees essentially with the major chemistry of the 4 granitoid associations, and is consistent with the 18 O/ 1 6O behavior which of ten varies sympathetically with Σ REE and S;O 2 . The presence of magmatic epidote, a high pressure phase, in three of these associations suggests that these rocks crystallized at a relatively great depth. (D.M.) [pt

The origin and tectonic setting of precambrian greywacke of Ribandar-Chimbel, Goa, India: Petrological and geochemical evidence

Digital Repository Service at National Institute of Oceanography (India)

Fernandes, G.Q.; Iyer, S.D.; Kotha, M.

, vanadium (25 to 144 ppm), nickel (up to 107 ppm) and chromium (up to 184 ppm), reflect abundance of clay minerals. The greywacke shows strongly fractionated REE patterns with LaN/YbN = 8 to 26 and with higher total REE abundances (up to 245 ppm). The low...

Rare Earth Element Distribution in the NE Atlantic: Evidence for Benthic Sources, Longevity of the Seawater Signal, and Biogeochemical Cycling

Directory of Open Access Journals (Sweden)

Kirsty C. Crocket

2018-04-01

Full Text Available Seawater rare earth element (REE concentrations are increasingly applied to reconstruct water mass histories by exploiting relative changes in the distinctive normalised patterns. However, the mechanisms by which water masses gain their patterns are yet to be fully explained. To examine this, we collected water samples along the Extended Ellett Line (EEL, an oceanographic transect between Iceland and Scotland, and measured dissolved REE by offline automated chromatography (SeaFAST and ICP-MS. The proximity to two continental boundaries, the incipient spring bloom coincident with the timing of the cruise, and the importance of deep water circulation in this climatically sensitive gateway region make it an ideal location to investigate sources of REE to seawater and the effects of vertical cycling and lateral advection on their distribution. The deep waters have REE concentrations closest to typical North Atlantic seawater and are dominated by lateral advection. Comparison to published seawater REE concentrations of the same water masses in other locations provides a first measure of the temporal and spatial stability of the seawater REE signal. We demonstrate the REE pattern is replicated for Iceland-Scotland Overflow Water (ISOW in the Iceland Basin from adjacent stations sampled 16 years previously. A recently published Labrador Sea Water (LSW dissolved REE signal is reproduced in the Rockall Trough but shows greater light and mid REE alteration in the Iceland Basin, possibly due to the dominant effect of ISOW and/or continental inputs. An obvious concentration gradient from seafloor sediments to the overlying water column in the Rockall Trough, but not the Iceland Basin, highlights release of light and mid REE from resuspended sediments and pore waters, possibly a seasonal effect associated with the timing of the spring bloom in each basin. The EEL dissolved oxygen minimum at the permanent pycnocline corresponds to positive heavy REE

Behavior of rare earth elements in fractured aquifers: an application to geological disposal criteria for radioactive waste

International Nuclear Information System (INIS)

Lee, Seung Gu; Kim, Yong Je; Lee, Kil Yong; Kim, Kun Han

2003-01-01

An understanding of the geochemistry of potential host rocks is very important in the site evaluation for construction of an underground geologic repository for radioactive waste. Because of similar valence and ionic radii and high similarity in electronic structure with trivalent actinides (such as Am 3+ and Cm 3+ ), the rare earth elements (REEs) have been used to predict the behavior of actinide-series elements in solution (Runde et al., 1992). For Am and Cm, which occur only in the trivalent states in most waste-disposal repository environments, the analogy with the REEs is particularly relevant. In order to discuss the behavior of REEs in geological media and to deduce the behavior of actinides in geological environments based on the REE abundance, and to provide an useful tool in deciding an optimum geological condition for radioactive disposal, we estimated the REE abundance from various kinds of fractured rock type. In fractured granitic aquifer, chondrite-normalized REE pattern show Eu positive anomaly due to fracture-filling calcite precipitation. However, in fractured meta-basaltic and volcanic tuffaceous aquifer, REE pattern do not show the change of Eu anomaly due to fracture-filling calcite precipitation. Eu shows very similar properties such as cohesive energy, ionic radii with coordination number compared to Am. Therefore, if we consider the Eu behavior in fractured rocks and the similar physical/chemical properties of Eu and Am, together, our results strongly suggest that Eu is a very useful analogue for predicting the behavior of Am in geological environment

Rare earth element mobility in arc-type volcanic rocks

International Nuclear Information System (INIS)

Kuschel, E.; Smith, I.E.M.

1990-01-01

Some samples from arc-type volcanic suites collected in northern New Zealand and southeastern Papua New Guinea show rare earth element (REE) and Y abundances which are enriched relative to the those typical of their respective associations. This enrichment appears to be the result of an alteration process which selectively mobilises the REE and re-precipitates them as REE-bearing minerals in veins and interstitial patches. The alteration is on a micron scale and is not detected in routine petrographic examination. It is emphasised that the pattern of REE mobility in young, fresh rocks is important to igneous geochemists who use REE abundances to constrain petrogenetic models and may also be important because it indicates the operation of a natural REE enrichment process which could operate in the formation of economic REE deposits. 3 refs., 5 figs

Using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to explore geochemical taphonomy of vertebrate fossils in the upper cretaceous two medicine and Judith River formations of Montana

Science.gov (United States)

Rogers, R.R.; Fricke, H.C.; Addona, V.; Canavan, R.R.; Dwyer, C.N.; Harwood, C.L.; Koenig, A.E.; Murray, R.; Thole, J.T.; Williams, J.

2010-01-01

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to determine rare earth element (REE) content of 76 fossil bones collected from the Upper Cretaceous (Campanian) Two Medicine (TMF) and Judith River (JRF) Formations of Montana. REE content is distinctive at the formation scale, with TMF samples exhibiting generally higher overall REE content and greater variability in REE enrichment than JRF samples. Moreover, JRF bones exhibit relative enrichment in heavy REE, whereas TMF bones span heavy and light enrichment fields in roughly equal proportions. TMF bones are also characterized by more negative Ce anomalies and greater U enrichment than JRF bones, which is consistent with more oxidizing diagenetic conditions in the TMF. Bonebeds in both formations show general consistency in REE content, with no indication of spatial or temporal mixing within sites. Previous studies, however, suggest that the bonebeds in question are attritional assemblages that accumulated over considerable time spans. The absence of geochemical evidence for mixing is consistent with diagenesis transpiring in settings that remained chemically and hydrologically stable during recrystallization. Lithology-related patterns in REE content were also compared, and TMF bones recovered from fluvial sandstones show relative enrichment in heavy REE when compared with bones recovered from fine-grained floodplain deposits. In contrast, JRF bones, regardless of lithologic context (sandstone versus mudstone), exhibit similar patterns of REE uptake. This result is consistent with previous reconstructions that suggest that channel-hosted microfossil bonebeds of the JRF developed via the reworking of preexisting concentrations embedded in the interfluve. Geochemical data further indicate that reworked elements were potentially delivered to channels in a recrystallized condition, which is consistent with rapid adsorption of REE postmortem. Copyright ?? 2010, SEPM (Society for

Geological and geochemical variations in Mid-Tertiary Ethiopian ...

African Journals Online (AJOL)

They are characterized by relatively flat REE patterns and lower Ti and ... other hand show higher concentrations of incompatible elements and more fractionated REE ... Location map of NW Ethiopian Plateau, Afar Rift and Main Ethiopian Rift ( ..... some samples for Sr-Nd- isotopic measurements were leached with 6N HCl ...

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

Science.gov (United States)

Tang, Jianwu; Johannesson, Karen H.

2010-12-01

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 containing weak (i.e., CH 3COO -) or strong (i.e., CO32-) ligands. The experimental results indicate that, in the absence of strong REE complexing ligands in solution, the amount of REEs released from the sand is small and the fractionation pattern of the released REEs appears to be controlled by the surface stability constants for REE sorption with Fe(III) oxides/oxyhydroxides. In the presence of strong solution complexing ligands, however, the amount and the fractionation pattern of the released REEs reflect the strength and variation of the stability constants of the dominant aqueous REE species across the REE series. The varying amount of REEs extracted by the different organic matter employed in the experiments indicates that organic matter from different sources has different complexing capacity for REEs. However, the fractionation pattern of REEs extracted by the various organic matter used in our experiments is remarkable consistent, being independent of the source and the concentration of organic matter used, as well as solution pH. Because natural aquifer sand and unpurified organic matter were used in our experiments, our experimental conditions are more broadly similar to natural systems than many previous laboratory experiments of REE-humic complexation that employed purified humic substances. Our results suggest that the REE loading effect on REE-humic complexation is negligible in natural waters as more abundant metal cations (e.g., Fe, Al) out-compete REEs for strong binding sites on organic matter. More specifically, our results indicate that REE

Chemical compositions of refractory inclusions in the Murchison C2 chondrite

International Nuclear Information System (INIS)

Ekambaram, V.; Kawabe, I.; Tanaka, T.; Davis, A.M.; Grossman, L.

1984-01-01

Samples from ten refractory inclusions in Murchison, some of which are splits of inclusions whose mineralogical and petrographic characteristics are known, have been analysed for thirty-six elements by neutron activation. Six inclusions have group II or group III patterns or variants of such patterns. Two inclusions, BB-5 and MUCH-1, have large negative Yb anomalies unaccompanied by correspondingly large negative Eu anomalies. It is possible that the latter condensed originally with group III patterns and preferentially took up Eu in later exchange processes under reducing conditions. One inclusion, SH-2, has heavy REE enrichment factors that increase with the refractoriness of the REE, indicating the presence of an extremely high-temperature, or ultrarefractory, REE condensate, but it also has a heavy REE/light REE ratio that indicates mixing of that component with a lower-temperature REE condensate. The frequency of highly fractionated REE patterns and absence of group I patterns suggest that refractory inclusions in Murchison stopped equilibrating with the nebular gas at higher temperatures than most Allende-coarse-grained inclusions. The results are discussed. (author)

Hf and Nd Isotopic and REE Investigations of Magnetite in a Proterozoic IOCG system: Fingerprinting Sources and Timing of Mineralisation

Science.gov (United States)

Schaefer, B. F.

2016-12-01

The Stuart Shelf on the margin of the Gawler Craton, South Australia, contains numerous economic and sub-econmic IOCG mineralised systems, including the giant Olympic Dam Cu-Au-U deposit. Hematite and magnetite have played a critical in the genesis of all of these deposits, and increasingly it appears that magnetite has been in equilibrium with either the final mineralised assemblage or was critical in transporting metals during the ore forming event. 14 magnetites and one hematite from three separate styles of iron oxide mineralisation associated with the Prominent Hill Cu-Au deposit were selected for detailed analysis. The REE and isotopic separations were all conducted by low blank wet chemistry and isotopes determined by TIMS (Nd) and MC-ICPMS (Hf). Magnetites associated with skarn style mineralsiation proximal to the ore body are unformly depleted in REE, whereas hematite within the ore and magmatic magmatites and whole rock gabbros from the nearby 1590Ma White Hill Gabbro intrusion are all relatively LREE enriched and display a comparable range in REE. Significantly however, magnetite separates almost invariably display more evolved Hf isotopic signatures than the host lithologies adjacent the economic mineralisation (dacites and metasediments at Prominent Hill mine) implying that the magnetites were sourcing their REE inventory dominantly from the local crust rather than a mantle derived source. In contrast, the magmatic magnetites from the White Hill Complex display Nd and Hf isotopes which are slightly more primitive, recording a greater relative mantle component, however still requiring a significant crustal input. Significantly, the hematite which contains the Au mineralisation preserves ɛNd (1590) = -4.04 and ɛHf (1590) = -6.05 essentially identical to the magmatic magnetites and their host gabbros in the White Hill complex and the basalts and dacites of the host Gawler Range Volcanics (ɛNd (1590) = -7.10 - -3.72 and ɛHf (1590) = -7.69 - -1

Condensation and fractionation of rare earths in the solar nebula

International Nuclear Information System (INIS)

Davis, A.M.; Grossman, L.

1979-01-01

Using the most recent thermodynamic data, the condensation behaviour of REE was calculated and several models were investigated to explain group II REE patterns in Allende inclusions. All models involve removal of large fractions of the more refractory heavy REE in an early condensate, probably perovskite, followed by condensation of the remainder at lower temperature. Previous workers found that the pattern of one such inclusion could not be fit by that of the gas remaining after ideal solution of REE in perovskite and, assuming the presence of only one REE component, calculated relative activity coefficients for REE in perovskite that would be needed to produce a match. In attempting to fit 20 group II patterns with this type of model, it was found that these activity coefficients could not be used for most inclusions and that the relationship between ionic radius and required activity coefficients had to change rapidly and irregularly over a narrow range of perovskite removal temperature. Because this feature and the high degree of non-ideality needed are most unreasonable, a different model is proposed in which two REE components control the patterns: (1) the gas remaining after removal of perovskite in which REE dissolve in ideal solution; (2) a material uniformly enriched in all REE. Two-component models in which solid solution of REE in perovskite is slightly non-ideal and activity coefficients vary negligibly over a narrow temperature range cannot be ruled out. By varying perovskite removal temperatures and the relative proportions of the two components, all 20 REE patterns can be satisfactorily explained. (author)

Instrumental neutron activation analysis of carbonatites from Homa Mountain, Kenya

International Nuclear Information System (INIS)

Ohde, S.

2004-01-01

Twenty eight (major and trace) elements including eight rare earth elements (REEs) in African carbonatite samples were determined by instrumental neutron activation analysis. The geochemical behavior of trace elements was studied in relation to the order of carbonatite intrusion from C1 to C4 through C2 and C3 at Homa Mountain, Kenya. The enrichment of Mn, Fe, Sr, Ba, Th, U and REE is found in the sixteen carbonatites examined in this study. The general increase in the concentrations of Na, Sc, Mn, Sb, Ba, Th, U and REE occurs from C1 to C4 through C2 and C2c, but C3 carbonatite shows a different pattern. The C3 carbonatite is extraordinarily enriched in Mn, Fe and Ba and is highly enriched in Cr, As, Sb and Th. The chondrite-normalized REE distribution pattern of the C3 carbonatite is not rich in the light REE. Strong fractionation between light and heavy REEs is found in the carbonatites, and moderate fractionation in the two alkalic igneous rock samples. In order to evaluate partitioning of REEs into carbonate, oxide and other mineral fractions, a selective chemical leaching technique on carbonatites was applied and is discussed. (author)

Cathodoluminescence and LA-ICP-MS chemistry of silicified wood enclosing wakefieldite - REEs and V migration during complex diagenetic evolution

Czech Academy of Sciences Publication Activity Database

Matysová, Petra; Götze, J.; Leichmann, J.; Škoda, R.; Strnad, L.; Drahota, P.; Matys Grygar, Tomáš

2016-01-01

Roč. 28, č. 5 (2016), s. 869-887 ISSN 0935-1221 Institutional support: RVO:67985891 ; RVO:61388980 Keywords : wakefieldite * xenotime * silicified wood * quartz * trace elements * REE * vanadium Subject RIV: DD - Geochemistry; DD - Geochemistry (UACH-T) Impact factor: 1.362, year: 2016

Signature of breccia complex/iron oxide- type U-REE mineralisation in the Khairagarh basin with special reference to Dongargaon- Lohara area, central India

Energy Technology Data Exchange (ETDEWEB)

Hansoti, S K; Sinha, D K [Department of Atomic Energy, Nagpur (India). Atomic Minerals Div.

1995-10-01

The Khairagarh basin having late Archaean- early Proterozoic basement is filled up by middle Proterozoic Khairagarh group volcano - sedimentary sequence, laid in the Kotri rift zone (KRZ) with imprints of repetitive volcanic, plutonic and tectonic activities. A strong thermal imprint of {approx} 1.5 Ga has been recorded in rocks of the basin that could be an effect of copious outpouring of basalts, dacites, ignimbrites, together with the emplacements of stocks of gabbros, gabbroic dolerites, dolerites, granites, granophyres, felsites, aplites, and quartz veins. Some of the basement rocks are enriched in Fe, Cu and other base metals and have been emplaced and assimilated by the volcano- plutonic rocks of the Nandgaon group and Malanjkhand granitoids. The Nandgaon group rocks and the Malanjkhand granitoids have anomalous intrinsic abundance of U, REE, Cu, Fe and quite a few metals in different sectors. Thermo-tectonic ({approx} 1.5 Ga) reactivation event(s) along the KRZ apart from facilitating formation of agglomerates, ignimbrites and tectonic breccias has promoted emplacement of plutonic and subvolcanic phases and their metasomatising and hydrothermal metal bearing fluids. In the Malanjkhand complex sector Cu{+-}Mo{+-}Fe{+-}Ag{+-}Au{+-}REE{+-}Zn metallisation and in the Dongargarh Massif sector U{+-}Th{+-}F{+-}Fe{+-}Pb{+-}Zn{+-}Cu{+-}REE{+-}Zr metallisation are manifested. The detection of Fe+U+REE {+-}Cu{+-}Ni metallisation in the Bortalao sandstones of the Dongargaon - Lohara area, located in between Malanjkhand ore zone and the Chandidongri (Dongargarh granite hosted) fluorite-rich and Pb{+-}Zn{+-}Cu{+-}U - bearing ore zone, considered to lie on the same (Malanjkhand - Chandidongri) fault/shear lineament is rated highly significant. (Abstract Truncated)

``From Fundamental Motives to Rational Expectation Equilibrium[REE, henceworth] of Indeterminacy''

Science.gov (United States)

Maksoed, Ssi, Wh-

For ``Principle of Indeterminacy''from Heisenberg states: ``one of the fundamental cornerstone of quantum mechanics is the Heisenberg uncertainty principle''.whereas canonically conjugate quantities can be determined simultaneously only with a characteristic indeterminacy[M. Arevalo Aguilar, et.al]. Accompanying Alfred North Whitehead conclusion in ``The Aims of Education''that mathematical symbols are artificial before new meanings given, two kinds of fundamental motives: (i) expectation-expectation, (ii) expectation-certainty inherently occurs with determinacy properties of rational expectation equilibrium(REE, henceworth)- Guido Ascari & Tizano Ropele:''Trend inflation, Taylor principle & Indeterminacy'', Kiel Institute, June 2007. Furthers, relative price expression can be compare of their α and (1 - α) configurations in the expression of possible activity. Acknowledgment to Prof[asc]. Dr. Bobby Eka Gunara for ``made a rank through physics'' denotes...

Uranium, thorium and rare earth elements distribution from different iron quadrangle spring waters

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Cláudia A.; Palmieri, Helena E.L.; Menezes, Maria A. de B.C.; Rodrigues, Paulo C.H., E-mail: cferreiraquimica@yahoo.com.br, E-mail: help@cdtn.br, E-mail: menezes@cdtn.br, E-mail: pchr@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-11-01

This study was conducted to evaluate the concentrations of thorium, uranium and the rare earth elements (REE) in 26 spring waters, as well as the patterns of the REE of the samples from the Cercadinho, Moeda and Caue aquifers in different municipalities of the Iron Quadrangle (Quadrilatero Ferrifero), located in the central-southeast of Minas Gerais state. The pH value of the ground waters ranged from 3.8 to 7.0, indicating an acid nature of most of the spring waters. The investigation of REE speciation showed that all the REEs exist in the free X{sup 3+} ionic forms, under the prevailing Eh and pH conditions. In the studied samples the uranium concentrations (<2.3-1176 ng L{sup -1}) were below the guideline level set by Brazilian legislation (Ministry of Health 518- 03/2004). Thorium concentrations ranged from <0.39-11.0 ng L{sup -1} and the sum of the REE ranged from 6.0 to 37657 ng L{sup -1}. As there are no permissible limits related for the REE and thorium for different water quality standards in Brazil, more attention must be paid to the local residents' health risk caused by spring waters (REEs were > 1000 ng L{sup -1}) originating from aquifers located in Sabara, Barao de Cocais, Santa Barbara, Mario Campos, Congonhas and Lavras Novas. The REEs patterns in the spring waters from the Cercadinho, Caue and Moeda aquifers are characterized by middle REE (MREE) enrichment compared to light REE (LREE) and heavy REEs (HREE), negative Ce anomalies (except for one sample) and positive Eu anomalies in all three aquifers studied. (author)

Applying a new understanding of supergene REE deposit formation to global exploration initiatives for environmentally sustainable resources

Science.gov (United States)

Hardy, Liam; Smith, Martin; Hood, Leo; Heller, Shaun; Faltyn, Rowan; Blum, Astrid; Bamberger, Axel

2017-04-01

Two new models have recently been proposed for the formation of REE ion-adsorption deposits and it is likely that they are both active in their related study profiles described in the Ambohimirahavavy Complex in Madagascar (Marquis et al, 2016) and the Serra de Monchique (SDM) complex in Portugal (Hardy et al, 2016). These are two separate environments presenting two different soil systems in terms of flora, protolith and structure. In the latosol profiles of SDM the natural sweating cycle of eucalyptus trees is proposed as the main geochemical cycling control for some 40% of Fe and 30% of Y, which have been observed migrating up and down profile seasonally between upper horizons and the rooting depths of these intensively farmed trees. If, through their natural cycle, eucalyptus trees in SDM are capable of concentrating depleted protolithic Y contents of 4-10ppm to some 140-160ppm in their enriched 150-200cm deep E horizons in only the 40 years since they were introduced to the region (Jenkins, 1979), then what potential deposits and concentrations may lay underneath older plantations across Brazil, Chile, China and most importantly, Australia, where these trees naturally cover some 16% of the entire continent. Eucalyptus is mostly farmed as pulp for paper mills and has lost its market value with the demand for paper decreasing, as the demand for REEs increases, ironically driven by the demand for the accessible technology to replace paper (EPA, 2012). Not only might there be great resources below these forests, but the removal of the aggressive intrusive species would be welcomed across Southern Europe and South America where they have limited market value and have destroyed local ecosystems and water supplies (Brito, 1999), where local people are actively seeking an alternative use of their lands. References: Brito, J. G. (1999). Management strategies for conservation of the lizard Lacerta schreiberi in Portugal. Biological conservation, 311-319. EPA. (2012

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

Science.gov (United States)

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

1992-01-01

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

Petrology and geochemistry of komatiites and tholeiites from Gorgona Island, Colombia

Science.gov (United States)

Aitken, Bruce G.; Echeverría, Lina M.

1984-04-01

Komatiitic rocks from Gorgona Island, Colombia, in contrast to their Archaean counterparts, occur as rather structureless flows. In addition, textural and mineralogical features indicate that the Gorgona komatiites may have crystallized from superheated liquids. Komatiitic rocks have MgO contents which range from 24 to 11 wt.% and plot on well-defined olivine (Fo90) control lines. Calculations show that potential evolved liquids (MgO<11 wt%) will be SiO2-poor. Komatiites, in this case, cannot be regarded as parental to the associated tholeiitic basalt sequence. On the basis of REE concentrations and Sr, Nd isotopic compositions, the associated basalts are found to be of two types. One type (K-tholeiite) is characterized by noticeably fractionated REE patterns and relatively primitive isotopic compositions similar to those of the komatiites. K-tholeiites, together with komatiites, are regarded as comprising a distinctive komatiitic suite. REE patterns within this suite show progressive depletion in the LREE from K-tholeiites to komatiites, and represent increasingly higher degrees of melting of the same mantle source region. The other type (T-tholeiite), representative of the bulk of the exposed basalt sequence, has flat REE patterns and relatively evolved isotopic compositions. This tholeiitic suite is clearly genetically unrelated to the komatiitic suite.

Possible impact-induced refractory-lithophile fractionations in EL chondrites

Science.gov (United States)

Rubin, Alan E.; Huber, Heinz; Wasson, John T.

2009-03-01

Literature data show that refractory-lithophile elements in most chondrite groups are unfractionated relative to CI chondrites; the principal exception is the EL-chondrite group whose observed falls (all of which are type 6) are depleted in Ca and light REE. In contrast, literature data and our new INAA data on EL3 PCA 91020, EL3 MAC 88136 and EL4 Grein 002 show that some replicates of these samples have nearly flat REE patterns (unlike those of EL6 chondrites); other replicates exhibit fractionated REE patterns similar to those of EL6 chondrites. Petrographic examination shows that many EL6 (and some EL3 and EL4) chondrites are impact-melt breccias or contain impact-melted portions. We suggest that the same impact processes that formed these breccias and produced melt are responsible for the observed bulk compositional fractionations in refractory-lithophile elements, i.e., EL6 chondrites were produced from initially unequilibrated EL3 material. When large amounts of impact heat were deposited, plagioclase and/or oldhamite (CaS) (the major REE carriers in enstatite chondrites) may have been melted and then transported appreciable (>10 cm) distances. EL6 chondrites represent the residuum that is depleted in REE (particularly in LREE) and Ca. Unlike the case for EL chondrites, our new INAA data on ALH 84170, EET 87746 and SAH 97096 (all EH3) show some scatter but are consistent with the EH group having uniform refractory-lithophile abundances.

Clustering of housing and household patterns using 2011 population census

CSIR Research Space (South Africa)

Dudeni-Tlhone, N

2013-11-01

Full Text Available the clusters to measure the effects of urban growth boundaries on land development patterns. Vickers and Rees (2007) clustered the 2001 census data from the UK National Statistics Office to provide area classifications that could be distributed by the Office... of National Statistics via their website. Cluster analysis is also commonly applied inter- nationally to land-use data for many different types of studies, including: to derive landscape ty- pologies (Van Eetvelde and Antrop, 2009), to differentiate between...

The rare earth element (REE) lanthanum (La) induces hormesis in plants.

Science.gov (United States)

Agathokleous, Evgenios; Kitao, Mitsutoshi; Calabrese, Edward J

2018-07-01

Lanthanum is a rare earth element (REE) which has been extensively studied due to its wide application in numerous fields with a potential accumulation in the environment. It has long been known for its potential to stimulate plant growth within a hormetic-biphasic dose response framework. This article provides evidence from a series of high resolution studies published within the last two decades demonstrating a substantial and significant occurrence of lanthanum-induced hormesis in plants. These findings suggest that hormetic responses should be built into the study design of hazard assessment study protocols and included in the risk assessment process. Hormesis also offers the opportunity to substantially improve cost benefit estimates for environmental contaminants, which have the potential to induce beneficial/desirable effects at low doses. Copyright © 2018 Elsevier Ltd. All rights reserved.

Rare earth element contents of the Lusi mud: An attempt to identify the environmental origin of the hot mudflow in East Java – Indonesia

Directory of Open Access Journals (Sweden)

Agustawijaya Didi Supriadi

2017-12-01

Full Text Available The Sidoarjo mudflow in East Java, Indonesia, has been erupting since May 29th, 2006. The eruption has been known as the Lusi (lumpur Sidoarjo, which was previously considered as a remote seismic event consequence, but current geyser-like activities show an association with a geothermal phenomenon. A method of characterizing rare earth elements (REE is commonly an effective tool for recognizing a geothermal system, and here it is adapted to particularly indicate the environmental origin of the Lusi mud. Results show that the Lusi hot mud is made of a porous smectite structure of a shale rock type, which becomes an ideal tank for trapping the REE, especially the light REE. Volcanic activities seem to be an important influence in the eruption; however, since there is a lack of significant isotopic evidences in the mobilization of the REE during the eruption, the chloride neutral pH water of the Lusi may hardly contain the REE. The moderate Ce and Eu anomalies found in the REE patterns of the mud strongly indicate a sea-floor basin as the most probable environment for the REE fractionation during the sedimentary rock formation, in which the weathering processes of volcanic rock origin enriched the Lusi shale with the REE.

Geochemistry of rare earth elements in the mainstream of the Yangtze River, China

International Nuclear Information System (INIS)

Li, X.; Zhang, S.; Wang, L.; Zhang, C.

1998-01-01

Water, suspended matter, and sediment samples were taken from 8 locations along the Yangtze River in 1992. The concentration and speciation (exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter, and residual forms) of rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) were determined by instrumental neutron activation analysis (INAA).The contents of the soluble fraction of REEs in the river are low, and REEs mainly reside in particulate form. In the particles, the chondrite-normalized distribution patterns show significant LREE enrichment and Eu-depletion. While normalized to shales, both sediments and suspended matter samples show relative LREE enrichment and HREE depletion. REEs are relatively enriched in fine-grained fractions of the sediments.exchangeable. About 65 to 85% of REEs in the particles exist in the residual form, and the exchangeable form is very low. High proportions of residual REEs reveal that REEs in sediments and suspended matter are controlled by their abundances in the earth's crust. Carbonate, Fe-Mn oxide and organic fractions of REEs in sediments account for 2.4-6.9%, 5.2-11.1%, and 7.3-14.0% of the total contents respectively. They are similar to those in the suspended matter. This shows that carbonates, Fe-Mn oxides and organic matter play important roles during the particle-water interaction processes. By normalization to shales, the 3 forms of REEs follow convex shapes according to atomic number with middle REE (Sm, Eu, and Tb) enrichment, while light REE and heavy REE are depleted. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

A new type of Nb (Ta)-Zr(Hf)-REE-Ga polymetallic deposit in the late Permian coal-bearing strata, eastern Yunnan, southwestern China: Possible economic significance and genetic implications

Energy Technology Data Exchange (ETDEWEB)

Dai, Shifeng; Wang, Xibo; Luo, Yangbing; Song, Zhentao; Ren, Deyi [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083 (China); Zhou, Yiping; Zhang, Mingquan; Wang, Jumin; Song, Xiaolin; Yang, Zong [Yunnan Institute of Coal Geology Prospection, Kunming 650218 (China); Jiang, Yaofa [Xuzhou Institute of Architectural Technology, Xuzhou 221116 (China)

2010-07-01

This paper describes a new type of Nb(Ta)-Zr(Hf)-REE-Ga polymetallic deposit of volcanic origin in the late Permian coal-bearing strata of eastern Yunnan, southwestern China. Well logging data (especially natural gamma-ray), geochemical data (high concentrations of Nb, Ta, Zr, Hf, REE, and Ga) and mineralogical compositions (Nb(Ta)-, Zr(Hf)-, or REE-bearing minerals rarely observed), together with the volcanic lithological characteristics indicate that there are thick (1-10 m, mostly 2-5 m) ore beds in the lower Xuanwei Formation (late Permian) in eastern Yunann of southwestern China. The ore beds are highly enriched in (Nb,Ta){sub 2}O{sub 5} (302-627 ppm), (Zr,Hf)O{sub 2} (3805-8468 ppm), REE (oxides of La-Lu + Y) (1216-1358 ppm), and Ga (52.4-81.3 ppm). The ore beds are mainly composed of quartz, mixed-layer illite-smectite, kaolinite, berthierine, and albite. Four types of ore beds in the study area were identified, namely, clay altered volcanic ash, tuffaceous clay, tuff, and volcanic breccia. Preliminary studies suggest that the high concentrations of otherwise rare metals were mainly derived from the alkalic pyroclastic rocks. The modes of occurrence, spatial distribution, and enrichment mechanism of the rare metals, however, require further study. (author)

Patherns in the rare earth elements of the Serra do Carambei granite (Parana) and the others associated ignous rocks

International Nuclear Information System (INIS)

Pinto-Coelho, C.V.; Marini, O.J.

1986-01-01

The rare earth elements (REE) distribution patters in igneous rocks of the Serra do Carambei Granite area (Parana) were a very important tool to elucidate the genetic processes and the cogenetic relationships between these rocks. The porphyroid facies of the Cunhaporanga Granitoid Complex has a REE distribution pattern characterized by decreasing concentrations in direction to the heavy rare earth elements (HREE) and the smooth Eu negative anomalie, compatible with amphibole fractionation during the magma ascent and the incipient plagioclase fractionation. The REE pattern of the Serra do Carambei Granite is characterized by the strong Eu negative anomalie, by the light rare earth element (LREE) depletion and by the HREE increase. This shape of the REE patterns is frequently observed in Sn-W granites, according to French authors. However in the igneous rocks of the Serra do Carambei Granite area this is not true. ''Rhyolite'' dytes intrusives in the Serra do Carambei Granite exhibit REE pattern similar to the wall rock, indicating then the same genetic processes. The Castro Group rhyolites have REE patterns with decreasing concentrations in direction to the HREE and smooth Eu negative anomalie. The REE distribution patterns is against the consanguinity between the ''rhyolites'' intruded in the Serra do Carambei Granite and the rhyolites of the Castro Group and also between these rhyolites and the above mentioned Granite. (author) [pt

Rare Earth element (REE) incorporation in natural calcite. Upper limits for actinide uptake in a secondary phase

International Nuclear Information System (INIS)

Stipp, S.L.S.; Christensen, J.T.; Waight, T.E.; Lakshtanov, L.Z.; Baker, J.A.

2006-01-01

Secondary minerals have the potential to sequester escaped actinides in the event of a radioactive waste repository failure, but currently, data to define their maximum uptake capacity are generally lacking. To estimate a maximum limit for solid solution in calcite, we took advantage of the behavioural similarities of the 4f-orbital lanthanides with some of the 5f-orbital actinides and used rare Earth element (REE) concentration as an analogue. A suite of 65 calcite samples, mostly pure single crystals, was assembled from a range of geological settings, ages and locations and analysed by isotope dilution MC-ICP-MS (multiple-collector inductively-coupled plasma mass spectroscopy). All samples were shown to contain significant lanthanide concentrations. The highest were in calcite formed from hydrothermal solutions and from carbonatite magma. Maximum total mole fraction of REE was 4.72 x 10 -4 , which represents one substituted atom for about 2000 Ca sites. In comparison, synthetic calcite, precipitated at growth rates slow enough to insure solid solution formation, incorporated 7.5 x 10 -4 mole fraction Eu(III). For performance assessment, we propose that 7.5 mmole substitution/kg calcite should be considered the upper limit for actinide incorporation in secondary calcite. The largest source of uncertainty in this estimate results from extrapolating lanthanide data to actinides. However, the data offer confidence that for waters in the hydrothermal temperature range, such as in the near-field, or at groundwater temperatures, such as in the far-field, if calcite formation is favoured and actinides are present, those with behaviour like the trivalent lanthanides, especially Am 3+ and Cm 3+ , will be incorporated. REE are abundant and widely distributed, and they have remained in calcite for millions of years. Thus, one can be certain that incorporated actinides will also remain immobilised in calcite formed in fractures and pore spaces, as long as solution conditions

Distribution of the rare earth elements in the surface sediments from the lower Wuding River of China

International Nuclear Information System (INIS)

Longjiang, M.; Duowen, M.; Ke, H.; Jinghong, Y.

2010-01-01

The abundance and distribution of rare earth elements (REE) and their signatures in the Wuding River of China were studied from samples of surface sediments and related to the geological formation in its watershed. The total REE (ΣREE) average concentrations of the Wuding River sediments (144.56 μg g -1 ), is lower than that in the Yangtze River sediments (167.10 μg g -1 ), getting closer to the values of the Yellow River sediments (137.76 μg g -1 ), being equivalent to the values of the UCC (the upper continental crust) (146.37 μg g-1). The chondrite-normalized REEs indicated LREE enrichment and flat HREE depletion and also showed a slightly negative Eu-anomaly. A similar chondrite-normalized REE distribution pattern between the Wuding River sediments and Yellow River sediments demonstrated the Wuding River sediments are the important material sources of the Yellow River sediments. UCC-normalized REE patterns between the Wuding River sediments and the Yellow River sediments were almost equivalent and close to the UCC. These implied the Wuding River sediments and the Yellow River sediments are subjected mostly to physical weathering due to higher erosion rates. Consequently, they can be used to trace the UCC compositions. (author)

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

Science.gov (United States)

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

2009-01-01

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

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

International Nuclear Information System (INIS)

Buil, Belen; Gomez, Paloma; Garralon, Antonio; Turrero, M. Jesus

2007-01-01

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)

Application of unsupervised pattern recognition approaches for exploration of rare earth elements in Se-Chahun iron ore, central Iran

Science.gov (United States)

Sarparandeh, Mohammadali; Hezarkhani, Ardeshir

2017-12-01

The use of efficient methods for data processing has always been of interest to researchers in the field of earth sciences. Pattern recognition techniques are appropriate methods for high-dimensional data such as geochemical data. Evaluation of the geochemical distribution of rare earth elements (REEs) requires the use of such methods. In particular, the multivariate nature of REE data makes them a good target for numerical analysis. The main subject of this paper is application of unsupervised pattern recognition approaches in evaluating geochemical distribution of REEs in the Kiruna type magnetite-apatite deposit of Se-Chahun. For this purpose, 42 bulk lithology samples were collected from the Se-Chahun iron ore deposit. In this study, 14 rare earth elements were measured with inductively coupled plasma mass spectrometry (ICP-MS). Pattern recognition makes it possible to evaluate the relations between the samples based on all these 14 features, simultaneously. In addition to providing easy solutions, discovery of the hidden information and relations of data samples is the advantage of these methods. Therefore, four clustering methods (unsupervised pattern recognition) - including a modified basic sequential algorithmic scheme (MBSAS), hierarchical (agglomerative) clustering, k-means clustering and self-organizing map (SOM) - were applied and results were evaluated using the silhouette criterion. Samples were clustered in four types. Finally, the results of this study were validated with geological facts and analysis results from, for example, scanning electron microscopy (SEM), X-ray diffraction (XRD), ICP-MS and optical mineralogy. The results of the k-means clustering and SOM methods have the best matches with reality, with experimental studies of samples and with field surveys. Since only the rare earth elements are used in this division, a good agreement of the results with lithology is considerable. It is concluded that the combination of the proposed

On L^1-Convergence Of Rees-Stanojević's Sums With Coefficients From The Class K

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Xhevat Z. Krasniqi

2010-12-01

Full Text Available In this paper are considered the modified cosine sums introduced by Rees and Stanojević  with coefficients from the class K. In addition, it is proved that the condition $\\lim_{n\\to \\infty}|a_{n+1}|\\log n= 0$ is a necessary and sufficient condition for the $L^{1}$-convergence of the cosine series. Also, an open problem about $L^{1}$-convergence for the $r-th$ derivative  of the cosine series is presented.

Fungal communities in wheat grain show significant co-existence patterns among species

DEFF Research Database (Denmark)

Nicolaisen, M.; Justesen, A. F.; Knorr, K.

2014-01-01

identified as ‘core’ OTUs as they were found in all or almost all samples and accounted for almost 99 % of all sequences. The remaining OTUs were only sporadically found and only in small amounts. Cluster and factor analyses showed patterns of co-existence among the core species. Cluster analysis grouped...... the 21 core OTUs into three clusters: cluster 1 consisting of saprotrophs, cluster 2 consisting mainly of yeasts and saprotrophs and cluster 3 consisting of wheat pathogens. Principal component extraction showed that the Fusarium graminearum group was inversely related to OTUs of clusters 1 and 2....

Environmental tracers for elucidating the weathering process in a phosphogypsum disposal site: Implications for restoration

Science.gov (United States)

Pérez-López, Rafael; Nieto, José M.; de la Rosa, Jesús D.; Bolívar, Juan P.

2015-10-01

This study provides geochemical data with the aim of identifying and tracing the weathering of phosphogypsum wastes stack-piled directly on salt-marshes of the Tinto River (Estuary of Huelva, SW Spain). With that purpose, different types of highly-polluted acid solutions were collected in the stack. Connection between these solutions and the estuarine environment was studied by geochemical tracers, such as rare earth elements (REE) and their North American Shale Composite (NASC)-normalized patterns and Cl/Br ratios. Phosphogypsum-related wastewaters include process water stored on the surface, pore-water contained in the phosphogypsum profile and edge outflow water emerging from inside the stack. Edge outflow waters are produced by waterlogging at the contact between phosphogypsum and the nearly impermeable marsh surface and discharge directly into the estuary. Process water shows geochemical characteristics typical of phosphate fertilizers, i.e. REE patterns with an evident enrichment of heavy-REE (HREE) with respect to middle-REE (MREE) and light-REE (LREE). By contrast, REE patterns of deeper pore-water and edge outflows are identical to those of Tinto River estuary waters, with a clear enrichment of MREE relative to LREE and HREE denoting influence of acid mine drainage. Cl/Br ratios of these solutions are very close to that of seawater, which also supports its estuarine origin. These findings clearly show that process water is not chemically connected with edge outflows through pore-waters, as was previously believed. Phosphogypsum weathering likely occurs by an upward flow of seawater from the marsh because of overpressure and permeability differences. Several recommendations are put forward in this study to route restoration actions, such as developing treatment systems to improve the quality of the edge outflow waters before discharging to the receiving environment.

Genomic patterns in Acropora cervicornis show extensive population structure and variable genetic diversity.

Science.gov (United States)

Drury, Crawford; Schopmeyer, Stephanie; Goergen, Elizabeth; Bartels, Erich; Nedimyer, Ken; Johnson, Meaghan; Maxwell, Kerry; Galvan, Victor; Manfrino, Carrie; Lirman, Diego

2017-08-01

Threatened Caribbean coral communities can benefit from high-resolution genetic data used to inform management and conservation action. We use Genotyping by Sequencing (GBS) to investigate genetic patterns in the threatened coral, Acropora cervicornis , across the Florida Reef Tract (FRT) and the western Caribbean. Results show extensive population structure at regional scales and resolve previously unknown structure within the FRT. Different regions also exhibit up to threefold differences in genetic diversity (He), suggesting targeted management based on the goals and resources of each population is needed. Patterns of genetic diversity have a strong spatial component, and our results show Broward and the Lower Keys are among the most diverse populations in Florida. The genetic diversity of Caribbean staghorn coral is concentrated within populations and within individual reefs (AMOVA), highlighting the complex mosaic of population structure. This variance structure is similar over regional and local scales, which suggests that in situ nurseries are adequately capturing natural patterns of diversity, representing a resource that can replicate the average diversity of wild assemblages, serving to increase intraspecific diversity and potentially leading to improved biodiversity and ecosystem function. Results presented here can be translated into specific goals for the recovery of A. cervicornis , including active focus on low diversity areas, protection of high diversity and connectivity, and practical thresholds for responsible restoration.

Geochemical Study on an Abandoned Copper Smelting Plant Using Rare Earth Elements

Science.gov (United States)

Sun, S. H.

2017-12-01

The Shuei Nan Dong Copper Smelting Plant smelting is located on the northern coast of New Taipei City, Taiwan. The plant built in 1906 for but has been shut down since 1987. However, the watershed is continuing to discharge acid mine water into the sea; and, the acid mine drainage releases high amounts of sulfate, heavy metals without any treatment. In this study, the water samples were sequentially collected along the main channel and its tributaries in the watershed. The results of hydrochemical analysis show that the untreated inflow water can be characterized with low pH value of 80% of the total variance and almost all chemical components have high loadings in the PC. Therefore, the hydrochemical properties in the watershed are mainly dominated by the mixing process between main channel and the major tributary but the geochemical reactions during flow down the channel is insignificant. Rare earth elements (REE) are an excellent tracer, which can indicate sources of chemical components and geochemical reactions in water. The analysis results demonstrate two distinct REE patterns. The water with low REE can be characterized by prominent Eu positive anomaly and Ce negative anomaly, which may result from the alteration of Na-plagioclase in sandstone and oxidation reaction when contact with air, respectively. On the contrary, the water with high REE shows only minor Ce negative anomaly and insignificant Eu positive anomaly. In addition, there is an enrichment of middle REE in high-REE water, which is quite different with the REE pattern of pyrite. According to the Grawunder's study (2014), it corresponds to the complexation to sulphite during pyrite oxidation. It is worth noting that REE show no considerable fractionation along the channel and confirms the results from PCA. It can be derived that the water may not reached equilibrium condition. A simple aerated retention pool could dramatically reduce the pollutants due to coprecipitation of iron oxide and aluminum

Aqueous speciation and the importance of particulate phase in hydro-geochemistry behaviour of U,Th and REE from uranium mine and Morro do Ferro, Pocos de Caldas - Brazil

International Nuclear Information System (INIS)

Jesus, Honerio Coutinho de

1996-04-01

This work, which was realized within the Natural Analogue Project Pocos de Caldas, had as its main objective the study of the colloidal behavior of U, Th, REE and some other elements of geochemical interest, in surface and groundwaters from the Osamu Utsumi mine and the Morro do ferro in Pocos de Caldas, Minas Gerais. Ultrafiltration techniques with flat membranes of different molecular mass exclusion limits (100 K, 10 K e 1K daltons) were used for this purpose. In addition, suspended matter (>0,45 μm), retained during pre-filtering of the waters, was analysed mineralogically and chemically (U, Th, REE, isotopic composition of U and Th, etc). Studies of the chemical composition of colloidal particles (<0,45 μm) and their size distributions were performed using ESCA and SEM, respectively. In addition, speciation studies by means of the MINEQL computation program were made to obtain information about the principal complexed species of relevant elements and the formation of solid phases. All the above mentioned investigations were aimed at better understanding of the migration and sorption behavior of U, Th and REE in both environments. The data obtained in this work indicate a low importance of particulate phases (colloids or suspended particles) for the migration behavior of U, Th and REE in waters from the Osumu Utsumi uranium mine and the Morro do ferro. However, these particles, composed mainly of ferric oxyhydrates and humic compounds, play an important role in sorption and immobilization processes. (author)

Large-Scale No-Show Patterns and Distributions for Clinic Operational Research

Directory of Open Access Journals (Sweden)

Michael L. Davies

2016-02-01

Full Text Available Patient no-shows for scheduled primary care appointments are common. Unused appointment slots reduce patient quality of care, access to services and provider productivity while increasing loss to follow-up and medical costs. This paper describes patterns of no-show variation by patient age, gender, appointment age, and type of appointment request for six individual service lines in the United States Veterans Health Administration (VHA. This retrospective observational descriptive project examined 25,050,479 VHA appointments contained in individual-level records for eight years (FY07-FY14 for 555,183 patients. Multifactor analysis of variance (ANOVA was performed, with no-show rate as the dependent variable, and gender, age group, appointment age, new patient status, and service line as factors. The analyses revealed that males had higher no-show rates than females to age 65, at which point males and females exhibited similar rates. The average no-show rates decreased with age until 75–79, whereupon rates increased. As appointment age increased, males and new patients had increasing no-show rates. Younger patients are especially prone to no-show as appointment age increases. These findings provide novel information to healthcare practitioners and management scientists to more accurately characterize no-show and attendance rates and the impact of certain patient factors. Future general population data could determine whether findings from VHA data generalize to others.

Large-Scale No-Show Patterns and Distributions for Clinic Operational Research.

Science.gov (United States)

Davies, Michael L; Goffman, Rachel M; May, Jerrold H; Monte, Robert J; Rodriguez, Keri L; Tjader, Youxu C; Vargas, Dominic L

2016-02-16

Patient no-shows for scheduled primary care appointments are common. Unused appointment slots reduce patient quality of care, access to services and provider productivity while increasing loss to follow-up and medical costs. This paper describes patterns of no-show variation by patient age, gender, appointment age, and type of appointment request for six individual service lines in the United States Veterans Health Administration (VHA). This retrospective observational descriptive project examined 25,050,479 VHA appointments contained in individual-level records for eight years (FY07-FY14) for 555,183 patients. Multifactor analysis of variance (ANOVA) was performed, with no-show rate as the dependent variable, and gender, age group, appointment age, new patient status, and service line as factors. The analyses revealed that males had higher no-show rates than females to age 65, at which point males and females exhibited similar rates. The average no-show rates decreased with age until 75-79, whereupon rates increased. As appointment age increased, males and new patients had increasing no-show rates. Younger patients are especially prone to no-show as appointment age increases. These findings provide novel information to healthcare practitioners and management scientists to more accurately characterize no-show and attendance rates and the impact of certain patient factors. Future general population data could determine whether findings from VHA data generalize to others.

Geochemical behaviour of rare earth elements on metasomatic alteration of volcanic rocks

International Nuclear Information System (INIS)

Jordanov, J.A.; Kunov, A.J.

1987-01-01

Investigations are carried out on metasomatically altered Paleogene latites in order to follow up the rare earth elements (REE) geochemical behavour. Representative samples of the initial rocks (latites), from propylitized latites and quartz-sericite rocks, as well as from dickite, alumite, diaspore and monoquartzites, are analysed. The results show that REE have a behaviour of moderately mobile elements. They undergo redistribution both in quantity and in the composition of the group. The different concentrations and changes in the ΣREE compared to the initial rocks are observed and direct relationships to the degree of endogenic leaching are made. The REE mobility and redistribution during the metasomatic alterations in the region investigated are controlled by the physical-chemical conditions which play a significant role both in determining the composition of the mineral paragenese and in the fixing of REE. The distribution patterns indicate that REE redistribution in the case of metasomatic alterations is almost isochemical without any supply from hydrothermal solutions

Seasonal and spatial variations of rare earth elements in rainwaters, river waters and total suspended particles in air in South Korea

International Nuclear Information System (INIS)

Ryu, J.S.; Lee, K.S.; Lee, S.G.; Lee, D.; Chang, H.W.

2007-01-01

In order to investigate the seasonal and spatial variations of rare earth element (REE) concentrations in natural waters in the central part of South Korea, rain and river waters were collected during 2003-2004. Total suspended particles (TSP) in air were also sampled to investigate the effect of the Asian dust (the Yellow sand) on the chemistry of rainwaters. All samples showed that the absolute concentrations of the light REEs (LREEs) were higher than those of the heavy REEs (HREEs). The post-Archean Australian shale (PAAS)-normalized REE patterns indicate that the REEs in TSP and rainwaters were affected by Asian dust and anthropogenic contaminant, whereas those of river waters were mainly controlled by the geology of their drainage basin and seasonal changes in water regime. The calculated fluxes and yields of total REEs (REEs plus Y) in the South Han River were much greater than those in the North Han River due to the more widespread distribution of sedimentary rocks in the drainage area and more efficient chemical weathering

Distinct 238U/235U ratios and REE patterns in plutonic and volcanic angrites: Geochronologic implications and evidence for U isotope fractionation during magmatic processes

Science.gov (United States)

Tissot, François L. H.; Dauphas, Nicolas; Grove, Timothy L.

2017-09-01

Angrites are differentiated meteorites that formed between 4 and 11 Myr after Solar System formation, when several short-lived nuclides (e.g., 26Al-26Mg, 53Mn-53Cr, 182Hf-182W) were still alive. As such, angrites are prime anchors to tie the relative chronology inferred from these short-lived radionuclides to the absolute Pb-Pb clock. The discovery of variable U isotopic composition (at the sub-permil level) calls for a revision of Pb-Pb ages calculated using an ;assumed; constant 238U/235U ratio (i.e., Pb-Pb ages published before 2009-2010). In this paper, we report high-precision U isotope measurement for six angrite samples (NWA 4590, NWA 4801, NWA 6291, Angra dos Reis, D'Orbigny, and Sahara 99555) using multi-collector inductively coupled plasma mass-spectrometry and the IRMM-3636 U double-spike. The age corrections range from -0.17 to -1.20 Myr depending on the samples. After correction, concordance between the revised Pb-Pb and Hf-W and Mn-Cr ages of plutonic and quenched angrites is good, and the initial (53Mn/55Mn)0 ratio in the Early Solar System (ESS) is recalculated as being (7 ± 1) × 10-6 at the formation of the Solar System (the error bar incorporates uncertainty in the absolute age of Calcium, Aluminum-rich inclusions - CAIs). An uncertainty remains as to whether the Al-Mg and Pb-Pb systems agree in large part due to uncertainties in the Pb-Pb age of CAIs. A systematic difference is found in the U isotopic compositions of quenched and plutonic angrites of +0.17‰. A difference is also found between the rare earth element (REE) patterns of these two angrite subgroups. The δ238U values are consistent with fractionation during magmatic evolution of the angrite parent melt. Stable U isotope fractionation due to a change in the coordination environment of U during incorporation into pyroxene could be responsible for such a fractionation. In this context, Pb-Pb ages derived from pyroxenes fraction should be corrected using the U isotope composition

Study of the distribution characteristics of rare earth elements in Solanum lycocarpum from different tropical environments in Brazil by neutron activation analysis; Estudo das caracteristicas de distribuicao de elementos terras raras em Solanum lycocarpum em diferentes ambientes tropicais do Brasil por ativacao neutronica

Energy Technology Data Exchange (ETDEWEB)

Maria, Sheila Piorino

2001-07-01

In this work, the concentration of eight rare earth elements (REE), La, Ce, Nd, Sm, Eu, Tb, Yb and Lu, was determined by neutron activation analysis (INAA), in plant leaves of Solanum lycocarpum. This species is a typical Brazilian 'cerrado' plant, widely distributed in Brazil. The analysis of the plant reference materials CRM Pine Needles (NIST 1575) and Spruce Needles (BCR 101) proved that the methodology applied was sufficiently accurate and precise for the determination of REE in plants. In order to better evaluate the uptake of the REE from the soil to the plant, the host soil was also analyzed by ESiAA. The studied areas were Salitre, MG, Serra do Cipo, MG, Lagoa da Pampulha and Mangabeiras, in Belo Horizonte, MG, and Cerrado de Emas, in Pirassununga, SP. The results were analyzed through the calculation of transfer factors soil-plant and by using diagrams normalized to chondrites. The data obtained showed different transfer factors from soil to plant as the subtract changes. Similar distribution patterns for the soil and the plant were obtained in all the studied sites, presenting an enrichment of the light REE (La to Sm), in contrast to the heavy REE (Eu to Lu), less absorbed. These results indicate that the light REE remain available to the plant in the more superficial soil layers. The similarity between the distribution patterns indicates a typical REE absorption by this species, in spite of the significant differences in the substratum . (author)

Study of the distribution characteristics of rare earth elements in Solanum lycocarpum from different tropical environments in Brazil by neutron activation analysis

International Nuclear Information System (INIS)

Maria, Sheila Piorino

2001-01-01

In this work, the concentration of eight rare earth elements (REE), La, Ce, Nd, Sm, Eu, Tb, Yb and Lu, was determined by neutron activation analysis (INAA), in plant leaves of Solanum lycocarpum. This species is a typical Brazilian 'cerrado' plant, widely distributed in Brazil. The analysis of the plant reference materials CRM Pine Needles (NIST 1575) and Spruce Needles (BCR 101) proved that the methodology applied was sufficiently accurate and precise for the determination of REE in plants. In order to better evaluate the uptake of the REE from the soil to the plant, the host soil was also analyzed by ESiAA. The studied areas were Salitre, MG, Serra do Cipo, MG, Lagoa da Pampulha and Mangabeiras, in Belo Horizonte, MG, and Cerrado de Emas, in Pirassununga, SP. The results were analyzed through the calculation of transfer factors soil-plant and by using diagrams normalized to chondrites. The data obtained showed different transfer factors from soil to plant as the subtract changes. Similar distribution patterns for the soil and the plant were obtained in all the studied sites, presenting an enrichment of the light REE (La to Sm), in contrast to the heavy REE (Eu to Lu), less absorbed. These results indicate that the light REE remain available to the plant in the more superficial soil layers. The similarity between the distribution patterns indicates a typical REE absorption by this species, in spite of the significant differences in the substratum . (author)

Dissolved rare earth elements in the central-western sector of the Ross Sea, Southern Ocean: Geochemical tracing of seawater masses.

Science.gov (United States)

Turetta, Clara; Barbaro, Elena; Capodaglio, Gabriele; Barbante, Carlo

2017-09-01

The present essay contributes to the existing literature on rare earth elements (REEs) in the southern hemisphere by presenting the first data, to our knowledge, on the vertical profiles of dissolved REEs in 71 samples collected in the central-western sector of the Ross Sea (Southern Ocean-SO). The REEs were measured in the water samples collected during the 2002-2003 and 2005-2006 austral summers. 4 samples were collected and analysed in the framework of a test experiment, as part of the WISSARD Project (Whillans Ice Stream Subglacial Access Research Drilling). Our results show significant differences between the REE patterns of the main water masses present in the SO: we could observe specific signature in the High Salinity Shelf Water (HSSW), Ice Shelf Water (ISW) and Low Salinity Shelf Water (LSSW). A significant increase in Terbium (Tb) concentration was observed in the HSSW and ISW, the two principal water masses contributing to the formation of Antarctic Bottom Water (AABW) in the Ross Sea area, and in LSSW. Some of the HSSW samples show enrichment in Neodymium (Nd). Dissolved REE could therefore be used as tracers to understand the deep circulation of the SO (Pacific sector). We hypothesize that: (I) the characteristic dissolved REE pattern may derive from the composition of source area and from the hydrothermal activity of the central-western area of the Ross Sea; (II) the Tb anomaly observed in the AABW on the South Australian platform could be partially explained by the contribution of AABW generated in the Ross Sea region. Copyright © 2017 Elsevier Ltd. All rights reserved.

Trace rare earth analysis by neutron activation and γ-ray/x-ray spectrometry

International Nuclear Information System (INIS)

Laul, J.C.; Nielson, K.K.; Wogman, N.A.

1977-01-01

A rare earth group separation scheme followed by photon energy analysis using Ge(Li) and intrinsic Ge detectors enhances significantly the detection of individual rare earth elements (REE) at or below the ppb level. Based on the x-ray and selected γ-ray energies, Ge(Li) γ-ray counting is favorable for 140 La, 141 Ce, 142 Pr, 153 Sm, 171 Er, and 177 Lu, whereas intrinsic Ge γ-ray counting is favorable for 143 Ce, 147 Nd, 160 Tb, and 166 Ho, and intrinsic Ge x-ray counting is favorable for 152 Eu and 175 Yb. Gamma-ray counting of 153 Gd and 170 Tm is equally sensitive with Ge(Li) or intrinsic Ge detectors. Precise measurements of the REE were made in the USGS geological samples BCR-1, W-1, AGV-1, G2, GSP-1 and PCC-1, the IAEA Soil-5, and the NBS orchard leaf and bovine liver standards. Their chondritic normalized REE patterns behave as a smooth function of the REE ionic radii. Interestingly, the REE patterns observed in orchard leaf and other plants are identical to the REE pattern in bovine liver. This comparison leads us to suggest that the plant REE patterns are probably not further fractionated by animals such as bovine during their dietary plant uptake

Rare earth element exchange through the Bosporus : The Black Sea as a net source of REEs to the Mediterranean Sea

NARCIS (Netherlands)

Schijf, Johan; Baar, Hein J.W. de; German, C.R.

1995-01-01

The Bosporus is the only source of seawater to the Black Sea and helps to maintain the basin-wide salinity gradient that caused the Black Sea to become the largest permanently anoxic basin in the world, some 3000 years ago. Concentrations of dissolved rare earth elements (REEs) in each of the three

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

Science.gov (United States)

Lund, K.; Tysdal, Russell G.; Evans, Karl V.; Kunk, Michael J.; Pillers, Renee M.

2011-01-01

The Cu-Co ± Au (± Ag ± Ni ± REE) ore deposits of the Blackbird district, east-central Idaho, have previously been classified as Besshi-type VMS, sedex, and IOCG deposits within an intact stratigraphic section. New studies indicate that, across the district, mineralization was introduced into the country rocks as a series of structurally controlled vein and alteration systems. Quartz-rich and biotite-rich veins (and alteration zones) and minor albite and siderite veinlets maintain consistent order and sulfide mineral associations across the district. Both early and late quartz veins contain chalcopyrite and pyrite, whereas intermediate-stage tourmaline-biotite veins host the cobaltite. Barren early and late albite and late carbonate (generally siderite) form veins or are included in the quartz veins. REE minerals, principally monazite, allanite, and xenotime, are associated with both tourmaline-biotite and late quartz veins. The veins are in mineralized intervals along axial planar cleavage, intrafolial foliation, and shears.

Strata-bound Fe-Co-Cu-Au-Bi-Y-REE deposits of the Idaho Cobalt Belt: Multistage hydrothermal mineralization in a magmatic-related iron oxide copper-gold system

Science.gov (United States)

Slack, John F.

2012-01-01

Mineralogical and geochemical studies of strata-bound Fe-Co-Cu-Au-Bi-Y-rare-earth element (REE) deposits of the Idaho cobalt belt in east-central Idaho provide evidence of multistage epigenetic mineralization by magmatic-hydrothermal processes in an iron oxide copper-gold (IOCG) system. Deposits of the Idaho cobalt belt comprise three types: (1) strata-bound sulfide lenses in the Blackbird district, which are cobaltite and, less commonly, chalcopyrite rich with locally abundant gold, native bismuth, bismuthinite, xenotime, allanite, monazite, and the Be-rich silicate gadolinite-(Y), with sparse uraninite, stannite, and Bi tellurides, in a gangue of quartz, chlorite, biotite, muscovite, garnet, tourmaline, chloritoid, and/or siderite, with locally abundant fluorapatite or magnetite; (2) discordant tourmalinized breccias in the Blackbird district that in places have concentrations of cobaltite, chalcopyrite, gold, and xenotime; and (3) strata-bound magnetite-rich lenses in the Iron Creek area, which contain cobaltiferous pyrite and locally sparse chalcopyrite or xenotime. Most sulfide-rich deposits in the Blackbird district are enclosed by strata-bound lenses composed mainly of Cl-rich Fe biotite; some deposits have quartz-rich envelopes.Whole-rock analyses of 48 Co- and/or Cu-rich samples show high concentrations of Au (up to 26.8 ppm), Bi (up to 9.16 wt %), Y (up to 0.83 wt %), ∑REEs (up to 2.56 wt %), Ni (up to 6,780 ppm), and Be (up to 1,180 ppm), with locally elevated U (up to 124 ppm) and Sn (up to 133 ppm); Zn and Pb contents are uniformly low (≤821 and ≤61 ppm, respectively). Varimax factor analysis of bulk compositions of these samples reveals geochemically distinct element groupings that reflect statistical associations of monazite, allanite, and xenotime; biotite and gold; detrital minerals; chalcopyrite and sparse stannite; quartz; and cobaltite with sparse selenides and tellurides. Significantly, Cu is statistically separate from Co and As

Rare earth elements determination and distribution patterns in sediments of polluted marine environment by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Akyil, S.; Yusof, A.M.; Wood, A.K.H.

2001-01-01

Results obtained from the analysis of sediment core samples taken from a fairly polluted marine environment were analyzed for the REE contents to determine the concentrations of La, Ce, Sm, Eu, Tb, Dy and Yb using instrumental neutron activation analysis. Core samples were divided into strata of between 2 to 3 cm intervals and prepared in the powdered form before irradiating them in a TRIGA Mk.II reactor. Down-core concentration profiles of La, Ce, Sm, Eu, Tb, Dy and Yb in 3 core sediments from three sites are obtained. The shale-normalized REE pattern from each site was examined and later used to explain the history of sedimentation by natural processes such as shoreline erosion and weathering products deposited on the seabed and furnishing some baseline data and/or pollution trend occurring within the study area

A Crystallization-Temperature Profile Through Paleo-Oceanic Crust (Wadi Gideah Transect, Oman Ophiolite): Application of the REE-in-Plagioclase-Clinopyroxene Partitioning Thermometer

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Mueller, S.; Hasenclever, J.; Garbe-Schönberg, D.; Koepke, J.; Hoernle, K.

2017-12-01

The accretion mechanisms forming oceanic crust at fast spreading ridges are still under controversial discussion. Thermal, petrological, and geochemical observations predict different end-member models, i.e., the gabbro glacier and the sheeted sill model. They all bear implications for heat transport, temperature distribution, mode of crystallization and hydrothermal heat removal over crustal depth. In a typical MOR setting, temperature is the key factor driving partitioning of incompatible elements during crystallization. LA-ICP-MS data for co-genetic plagioclase and clinopyroxene in gabbros along a transect through the plutonic section of paleo-oceanic crust (Wadi Gideah Transect, Oman ophiolite) reveal that REE partitioning coefficients are relatively constant in the layered gabbro section but increase for the overlying foliated gabbros, with an enhanced offset towards HREEs. Along with a systematic enrichment of REE's with crustal height, these trends are consistent with a system dominated by in-situ crystallization for the lower gabbros and a change in crystallization mode for the upper gabbros. Sun and Liang (2017) used experimental REE partitioning data for calibrating a new REE-in-plagioclase-clinopyroxene thermometer that we used here for establishing the first crystallization-temperature depth profile through oceanic crust that facilitates a direct comparison with thermal models of crustal accretion. Our results indicate crystallization temperatures of about 1220±8°C for the layered gabbros and lower temperatures of 1175±8°C for the foliated gabbros and a thermal minimum above the layered-to-foliated gabbro transition. Our findings are consistent with a hybrid accretion model for the oceanic crust. The thermal minimum is assumed to represent a zone where the descending crystal mushes originating from the axial melt lens meet with mushes that have crystallized in situ. These results can be used to verify and test thermal models (e.g., Maclennan et al

Endoscopy and homogeneous-heterogeneous reactions in MHD radiative peristaltic activity of Ree-Eyring fluid

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Hayat, Tasawar; Akram, Javaria; Alsaedi, Ahmed; Zahir, Hina

2018-03-01

Endoscopic and homogeneous-heterogeneous reactions in MHD peristalsis of Ree-Eyring fluid are addressed. Mathematical modeling and analysis have been performed by utilizing cylindrical coordinates. Nonlinear thermal radiation is present. Impact of slip boundary conditions on temperature and velocity on outer tube are taken into consideration. Lubrication approach is employed. The nonlinear system is executed numerically for solutions of velocity, temperature and concentration. Graphical results are obtained to predict physical interpretation of various embedded parameters. It is noted that homogeneous and heterogeneous reactions affect the concentration alternatively. Moreover Brinkman number rises the temperature and heat transfer coefficient whereas thermal slip drops temperature and heat transfer rate.

The origin of the ore-bearing solution in the Pb-Zn veins of the western Harz, Germany, as deduced from rare-earth element and isotope distributions in calcites

International Nuclear Information System (INIS)

Moeller, P.; Parekh, P.P.; Morteani, G.; Hoefs, J.

1979-01-01

Rare-earth element (REE) and stable-isotope distribution patterns in calcites from the mining areas of St. Andreasberg, Clausthal and Bad Grund, western Harz, Germany, have been determined. Three types of REE distribution patterns were found: type I is characterized by high amounts of light REE without any Ce and Eu anomalies and relativity homogeneous C- and O-isotopic composition. Type II displays conspicuous Ce and Eu anomalies at lower levels of concentration of the light REE. Type III has very low amounts of REE. Type II and III exhibit a more variable C-isotopic composition than type I. The calcite with type I patterns is assumed to be derived mainly from magnetic waters. A possible source for the magnetic waters seems to be the Brocken-Oker granite. Type-II calcites and the sulfides are probably derived from upheated country rock whereas calcite with type-III pattern mineralized from relatively cold descending solutions. The calcite with type-I pattern turns out to be not in equilibrium with sulfides, although both are in intimate contact, e.g. in banded ores. This non-equilibrium indicates two independent sources for this calcite with type-I pattern and the sulfides. (Auth.)

Chemical compositions and Sr, Nd isotope ratios of gabbroic xenoliths in calc-alkali andesites of Naeba and Torikabuto volcanoes, North Fossa Magna, central Japan

International Nuclear Information System (INIS)

Shimazu, Mitsuo; Kawano, Yoshinobu; Kaji, Kiyoshi; Igarashi, Satoshi.

1991-01-01

Gabbroic, doleritic and basaltic xenoliths found in calc-alkali andesites of Naeba and Torikabuto volcanoes are geochemically divided into three groups. Gabbro A of the group 1 from Naeba is rich in MgO and Ni, poor in alkalis, and shows depleted REE pattern resembling those of Ichinomegata (Sp. No.2232) and Hakone (HKG1, HKG2) volcanoes. On the basis the REE pattern and high Al IV contents in clinopyroxenes, gabbro A is interpreted to have been cumulate from a primary magma generated by partial melting of upper mantle. From REE pattern, gabbros of the group 2 from Ichinomegata (Sp. No.2218) may have derived from low alkali tholeiite magma which have been formed by removal of material such as the group 1 gabbro at shallow depth. Doleritic and basaltic xenoliths of the group 3 from Naeba, gabbroic xenoliths from Torikabuto and Umikawa are poorer in MgO and richer in alkalis than those of the group 1 and show enriched pattern in REE resembling that of high alkali tholeiite and contain clinopyroxenes having low Al IV . Therefore, these rocks are considered to be differentiates of high alkali tholeiite magma at shallow depth. On εNd- 87 Sr/ 86 Sr diagram, isotope data of gabbro A of the group 1 plot near those of andesites from Asama and Myoko volcanoes of the North Fossa Magna. It is interpreted that these rocks have derived from the same mantle source as the Asama and Myoko volcanoes which are richer in incompatible elements than those of MORB. (author)

Behaviour of major, minor and trace elements (including REEs during kaolinization processes at Zonouz deposit, northeast of Marand, East Azarbaidjan province

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Vahideh Alipour

2011-11-01

Full Text Available The Zonouz kaolin deposit is located ~15 km northeast of Marand, East-Azarbaidjan province. Based on physical features in field investigations, such as color, five distinct kaolin types including (1 white, (2 lemon, (3 gray, (4 brown, and (5 yellow are distinguished in the deposit. Field evidence and petrographic studies indicate that the deposit is genetically close to trachy-andesite rocks. According to mineralogical data, the deposit contains quartz, kaolinite, montmorillonite, calcite, pyrophyllite, chlorite, muscovite-illite, dolomite, hematite, and anatase minerals. Geochemical data indicate that function of alteration processes on trachy-andesite rocks during development of Zonouz ore deposit was accompanied by leaching of elements such as Al, Na, K, Rb, Ba, V, Hf, Cu, Zr, Tm, Yb, and Lu, enrichment of elements such as U, Nb, and Ta, and leaching-fixation of elements such as Si, Fe, Ca, Mg, Ti, Mn, P, Cs, Sr, Th, Co, Cr, Ni, Y, Ga, LREE, Tb, Dy, Ho, and Er. Incorporation of obtained results from mineralogical and geochemical studies show that physico-chemical conditions of alteration environment, the relative stability of primary minerals, surface adsorption, preferential sorption by metallic oxides, existing of organic matters, scavenging and concentration processes, and fixation in neomorphic mineralogical phases played important role in distribution of elements in the deposit. Geochemical studies show that development of the deposit is relative to two types of processes, (1 hypogene and (2 supergene. The distribution pattern of REEs indicates that differentiation degree of LREEs from HREEs in supergene kaolins is more than hypogene kaolins. Geochemical studies indicate that minerals such as Mn-oxides, zircon, anatase, hematite, cerianite, and secondary phosphates (monazite, rhabdophane, churchite, and zenotime are the potential hosts for rare earth elements in this deposit.

Seasonal and spatial variations in rare earth elements and yttrium of dissolved load in the middle, lower reaches and estuary of the Minjiang River, southeastern China

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Zhu, Xuxu; Gao, Aiguo; Lin, Jianjie; Jian, Xing; Yang, Yufeng; Zhang, Yanpo; Hou, Yuting; Gong, Songbai

2017-09-01

With the aim of elucidating the spatial and seasonal behaviors of rare earth elements (REEs), we investigated the dissolved REE concentrations of surface water collected during four seasons from middle, lower reaches and estuary of the Minjiang River, southeastern China. The results display that the REE abundances in Minjiang River, ranging from 3.3-785.9 ng/L, were higher than those of many of the major global rivers. The total REE concentrations (ΣREE) were seasonally variable, averaging in 5 937.30, 863.79, 825.65 and 1 065.75 ng/L during second highest flow (SHF), normal flow (NF), low flow (LF) and high flow (HF) season, respectively. The R (L/M) and R (H/M) ratios reveal the spatial and temporal variations of REE patterns, and particularly vary apparently in the maximum turbidity zone and estuary. REE patterns of dissolved loads are characterized by progressing weaker LREEs-enrichment and stronger HREEs-enrichment downstream from middle reaches to estuary during all four seasons. Comparing with NF and LF seasons, in which REE patterns are relatively flat, samples of SHF season have more LREE-enriched and HREE-depleted patterns that close to parent rocks, while samples of HF season are more LREEs-depleted and HREE-enriched. REE fractionations from the middle to lower reaches are stronger in the SHF and HF seasons than those in NF and LF seasons. Generally, spatial and seasonal variations in REE abundance and pattern are presumably due to several factors, such as chemical weathering, mixture with rainfall and groundwater, estuarine mixing, runoff, biological production and mountain river characters, such as strong hydrodynamic forces and steep slopes. The highest Gd/Gd* always occurs at north ports during all four seasons, where most of the large hospitals are located. This suggests Gd anomalies are depended on the density of modern medical facilities. Y/Ho ratios fluctuate and positively correlate to salinity in estuary, probably because of the geochemical

Analyzing Solutions High in Total Dissolved Solids for Rare Earth Elements (REEs) Using Cation Exchange and Online Pre-Concentration with the seaFAST2 Unit; NETL-TRS-7-2017; NETL Technical Report Series; U.S. Department of Energy, National Energy Technology Laboratory: Albany, OR, 2017; p 32

Energy Technology Data Exchange (ETDEWEB)

Yang, J. [National Energy Technology Lab. (NETL), Albany, OR (United States); Oregon State Univ., Corvallis, OR (United States). College of Earth, Ocean, and Atmospheric Science; Torres, M. [Oregon State Univ., Corvallis, OR (United States). College of Earth, Ocean, and Atmospheric Science; Verba, C. [National Energy Technology Lab. (NETL), Albany, OR (United States); Oregon State Univ., Corvallis, OR (United States); Hakala, A. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

2017-08-01

The accurate quantification of the rare earth element (REE) dissolved concentrations in natural waters are often inhibited by their low abundances in relation to other dissolved constituents such as alkali, alkaline earth elements, and dissolved solids. The high abundance of these constituents can suppress the overall analytical signal as well as create isobaric interferences on the REEs during analysis. Waters associated with natural gas operations on black shale plays are characterized by high salinities and high total dissolved solids (TDS) contents >150,000 mg/L. Methods used to isolate and quantify dissolved REEs in seawater were adapted in order to develop the capability of analyzing REEs in waters that are high in TDS. First, a synthetic fluid based on geochemical modelling of natural brine formation fluids was created within the Marcellus black shale with a TDS loading of 153,000 mg/L. To this solution, 1,000 ng/mL of REE standards was added based on preliminary analyses of experimental fluids reacted at high pressure and temperature with Marcellus black shale. These synthetic fluids were then run at three different dilution levels of 10, 100, and 1,000–fold dilutions through cation exchange columns using AG50-X8 exchange resin from Eichrom Industries. The eluent from the cation columns were then sent through a seaFAST2 unit directly connected to an inductively coupled plasma mass spectrometer (ICP-MS) to analyze the REEs. Percent recoveries of the REEs ranged from 80–110% and fell within error for the external reference standard used and no signal suppression or isobaric interferences on the REEs were observed. These results demonstrate that a combined use of cation exchange columns and seaFAST2 instrumentation are effective in accurately quantifying the dissolved REEs in fluids that are >150,000 mg/L in TDS and have Ba:Eu ratios in excess of 380,000.

Possible Involvement of Permian Phosphoria Formation Oil as a Source of REE and Other Metals Associated with Complex U-V Mineralization in the Northern Bighorn Basin?

Directory of Open Access Journals (Sweden)

Anita L. Moore-Nall

2017-11-01

Full Text Available The origin of V, U, REE and other metals in the Permian Phosphoria Formation have been speculated and studied by numerous scientists. The exceptionally high concentrations of metals have been interpreted to reflect fundamental transitions from anoxic to oxic marine conditions. Much of the oil in the Bighorn Basin, is sourced by the Phosphoria Formation. Two of the top 10 producing oil fields in Wyoming are located approximately 50 km west of two abandoned U-V mining districts in the northern portion of the basin. These fields produce from basin margin anticlinal structures from Mississippian age reservoir rock. Samples collected from abandoned U-V mines and prospects hosted in Mississippian aged paleokarst in Montana and Wyoming have hydrocarbon residue present and contain anomalous high concentrations of many metals that are found in similar concentrations in the Phosphoria Formation. As, Hg, Mo, Pb, Tl, U, V and Zn, often metals of environmental concern occur in high concentrations in Phosphoria Formation samples and had values ranging from 30–1295 ppm As, 0.179–12.8 ppm Hg, 2–791 ppm Mo, <2–146 ppm Pb, 10–490 ppm Tl, 907–86,800 ppm U, 1240–18,900 ppm V, and 7–2230 ppm Zn, in mineralized samples from this study. The REE plus Y composition of Madison Limestone- and limestone breccia hosted-bitumen reflect similar patterns to both mineralized samples from this study and to U.S. Geological Survey rock samples from studies of the Phosphoria Formation. Geochemical, mineralogical and field data were used to investigate past theories for mineralization of these deposits to determine if U present in home wells and Hg content of fish from rivers on the proximal Crow Indian Reservation may have been derived from these deposits or related to their mode of mineralization.

Rare earth elements mobility processes in an AMD-affected estuary: Huelva Estuary (SW Spain).

Science.gov (United States)

Lecomte, K L; Sarmiento, A M; Borrego, J; Nieto, J M

2017-08-15

Huelva Estuary is a transition zone where REE-rich acidic waters interact with saline-alkaline seawater. This mixing process influences the geochemical and mineralogical characteristics of particulate and dissolved fractions. The Tinto River has >11,000μgL -1 dissolved REE (pH=1.66), whereas seawater only reaches 8.75·10 -2 μgL -1 dissolved REE (pH=7.87). REE-normalized patterns in "pH<6 solutions" are parallel and show similarities, diminishing their concentration as pH increases. Sequential extraction performed on the generated precipitates of mixed solutions indicates that most REE are associated to the residual phase. In a second order, REE are associated with soluble salts at pH3 and 3.5 whereas in sediments generated at pH4 and 5, they are distributed in salts (1° extraction), poorly crystallized Fe-bearing minerals (schwertmannite, 3° extraction) and well crystallized Fe-bearing minerals (goethite - hematite, 4° extraction). Finally, precipitated REE are highest at pH6 newly formed minerals with a release to solution in higher pH. Copyright © 2017 Elsevier Ltd. All rights reserved.

Soil Bacterial and Fungal Communities Show Distinct Recovery Patterns during Forest Ecosystem Restoration.

Science.gov (United States)

Sun, Shan; Li, Song; Avera, Bethany N; Strahm, Brian D; Badgley, Brian D

2017-07-15

Bacteria and fungi are important mediators of biogeochemical processes and play essential roles in the establishment of plant communities, which makes knowledge about their recovery after extreme disturbances valuable for understanding ecosystem development. However, broad ecological differences between bacterial and fungal organisms, such as growth rates, stress tolerance, and substrate utilization, suggest they could follow distinct trajectories and show contrasting dynamics during recovery. In this study, we analyzed both the intra-annual variability and decade-scale recovery of bacterial and fungal communities in a chronosequence of reclaimed mined soils using next-generation sequencing to quantify their abundance, richness, β-diversity, taxonomic composition, and cooccurrence network properties. Bacterial communities shifted gradually, with overlapping β-diversity patterns across chronosequence ages, while shifts in fungal communities were more distinct among different ages. In addition, the magnitude of intra-annual variability in bacterial β-diversity was comparable to the changes across decades of chronosequence age, while fungal communities changed minimally across months. Finally, the complexity of bacterial cooccurrence networks increased with chronosequence age, while fungal networks did not show clear age-related trends. We hypothesize that these contrasting dynamics of bacteria and fungi in the chronosequence result from (i) higher growth rates for bacteria, leading to higher intra-annual variability; (ii) higher tolerance to environmental changes for fungi; and (iii) stronger influence of vegetation on fungal communities. IMPORTANCE Both bacteria and fungi play essential roles in ecosystem functions, and information about their recovery after extreme disturbances is important for understanding whole-ecosystem development. Given their many differences in phenotype, phylogeny, and life history, a comparison of different bacterial and fungal recovery

Changes in depositional environment for the past 35 years in the Thane Creek, central west coast of India: Inferences from REEs, metals and magnetic properties

Digital Repository Service at National Institute of Oceanography (India)

Fernandes, L.L.; Kessarkar, P.M.; Parthiban, G.; Rao, V.P.

The role of diagenetic processes in influencing the behaviour of metals (Fe, Mn, Cu, Ni, Zn), rare earth elements (REEs) and environmental magnetic parameters in two sediment cores from a polluted creek environment (the Thane Creek, Mumbai...

Origin of middle rare earth element enrichments in acid waters of a Canadian high Arctic lake.

Science.gov (United States)

Johannesson, Kevin H.; Zhou, Xiaoping

1999-01-01

-Middle rare earth element (MREE) enriched rock-normalized rare earth element (REE) patterns of a dilute acidic lake (Colour Lake) in the Canadian High Arctic, were investigated by quantifying whole-rock REE concentrations of rock samples collected from the catchment basin, as well as determining the acid leachable REE fraction of these rocks. An aliquot of each rock sample was leached with 1 N HNO 3 to examine the readily leachable REE fraction of each rock, and an additional aliquot was leached with a 0.04 M NH 2OH · HCl in 25% (v/v) CH 3COOH solution, designed specifically to reduce Fe-Mn oxides/oxyhydroxides. Rare earth elements associated with the leachates that reacted with clastic sedimentary rock samples containing petrographically identifiable Fe-Mn oxide/oxyhydroxide cements and/or minerals/amorphous phases, exhibited whole-rock-normalized REE patterns similar to the lake waters, whereas whole-rock-normalized leachates from mafic igneous rocks and other clastic sedimentary rocks from the catchment basin differed substantially from the lake waters. The whole-rock, leachates, and lake water REE data support acid leaching or dissolution of MREE enriched Fe-Mn oxides/oxyhydroxides contained and identified within some of the catchment basin sedimentary rocks as the likely source of the unique lake water REE patterns. Solution complexation modelling of the REEs in the inflow streams and lake waters indicate that free metal ions (e.g., Ln 3+, where Ln = any REE) and sulfate complexes (LnSO 4+) are the dominant forms of dissolved REEs. Consequently, solution complexation reactions involving the REEs during weathering, transport to the lake, or within the lake, cannot be invoked to explain the MREE enrichments observed in the lake waters.

Investigating Rare Earth Element Systematics in the Marcellus Shale

Science.gov (United States)

Yang, J.; Torres, M. E.; Kim, J. H.; Verba, C.

2014-12-01

The lanthanide series of elements (the 14 rare earth elements, REEs) have similar chemical properties and respond to different chemical and physical processes in the natural environment by developing unique patterns in their concentration distribution when normalized to an average shale REE content. The interpretation of the REE content in a gas-bearing black shale deposited in a marine environment must therefore take into account the paleoredox conditions of deposition as well as any diagenetic remobilization and authigenic mineral formation. We analyzed 15 samples from a core of the Marcellus Shale (Whipkey ST1, Greene Co., PA) for REEs, TOC, gas-producing potential, trace metal content, and carbon isotopes of organic matter in order to determine the REE systematics of a black shale currently undergoing shale gas development. We also conducted a series of sequential leaching experiments targeting the phosphatic fractions in order to evaluate the dominant host phase of REEs in a black shale. Knowledge of the REE system in the Marcellus black shale will allow us to evaluate potential REE release and behavior during hydraulic fracturing operations. Total REE content of the Whipkey ST1 core ranged from 65-185 μg/g and we observed three distinct REE shale-normalized patterns: middle-REE enrichment (MREE/MREE* ~2) with heavy-REE enrichment (HREE/LREE ~1.8-2), flat patterns, and a linear enrichment towards the heavy-REE (HREE/LREE ~1.5-2.5). The MREE enrichment occurred in the high carbonate samples of the Stafford Member overlying the Marcellus Formation. The HREE enrichment occurred in the Union Springs Member of the Marcellus Formation, corresponding to a high TOC peak (TOC ~4.6-6.2 wt%) and moderate carbonate levels (CaCO3 ~4-53 wt%). Results from the sequential leaching experiments suggest that the dominant host of the REEs is the organic fraction of the black shale and that the detrital and authigenic fractions have characteristic MREE enrichments. We present our

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

Science.gov (United States)

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

1997-01-01

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

Determination of rare earth elements in seawater by ICP-MS after preconcentration with a chelating resin-packed minicolumn

International Nuclear Information System (INIS)

Zhu Yanbei; Itoh, Akihide; Fujimori, Eiji; Umemura, Tomonari; Haraguchi, Hiroki

2006-01-01

Rare earth elements (REEs) in seawater were preconcentrated 20-fold (from 50 to 2.5 ml) by a chelating resin-packed minicolumn device and determined by inductively coupled plasma mass spectrometry (ICP-MS). The recoveries for REEs were in the range from 90% for Eu and Dy to 98% for Yb, and their standard deviations were less than 4%. The lower detection limits for REEs ranged from 0.06 ng l -1 for Lu to 0.5 ng l -1 for Sm. The analytical results for REEs in seawater reference materials (NASS-5, CASS-3, and CASS-4), the Take Island coastal seawater, and the Ise Bay coastal seawater were evaluated as the REE distribution patterns with shale-normalization and deep seawater-normalization. Slight relative enrichments of heavy REEs were observed in the Take Island coastal seawater and the Ise Bay coastal seawater, which might be attributed to the input from the river flows containing more dissolved heavy REEs. In addition, positive anomalies of Sm were found in the normalized REE distribution patterns for NASS-5, CASS-3, and CASS-4, which would be attributed to the contamination in the preparation process of reference materials by NRC

Application of nuclear analytical techniques to trace elements in cenozoic basalt and their mantle xenoliths from Aershan area in Inner Mongolia, China

International Nuclear Information System (INIS)

Yu Fusheng; Han Song; Huang Yuying; He Wei; Cao Jie; Wang Hongyue

2005-01-01

Basaltic samples from different locations in Aershan area determined by instrumental neutron activation analysis (INAA) have the same distribution patterns of REE and trace elements. The similar REE contents of the same minerals without inclusions from different xenolith suggest that the mantle source region under different active volcanoes have the same composition. The REE content differences between the same minerals with and without melt inclusions selected from the same mantle xenolith indicate that the melt inclusions are rich in REE. The same patterns of trace elements of inclusions and host minerals from different xenolith analyzed by SRXRF suggest that the mantle fluid has no notable heterogeneity in Aershan area. (authors)

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

Energy Technology Data Exchange (ETDEWEB)

Jones, Adele M.; Xue, Youjia [School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Kinsela, Andrew S. [School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Institute for Environmental Research (IER), Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234 (Australia); Wilcken, Klaus M. [Institute for Environmental Research (IER), Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234 (Australia); Collins, Richard N., E-mail: richard.collins@unsw.edu.au [School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia)

2016-03-15

Donnan dialysis has been applied to forty filtered drainage waters collected from five coastal lowland acid sulfate soil (CLASS) catchments across north-eastern NSW, Australia. Despite having average pH values < 3.9, 78 and 58% of Al and total Fe, respectively, were present as neutral or negatively-charged species. Complementary isotope dilution experiments with {sup 55}Fe and {sup 26}Al demonstrated that only soluble (i.e. no colloidal) species were present. Trivalent rare earth elements (REEs) were also mainly present (> 70%) as negatively-charged complexes. In contrast, the speciation of the divalent trace metals Co, Mn, Ni and Zn was dominated by positively-charged complexes and was strongly correlated with the alkaline earth metals Ca and Mg. Thermodynamic equilibrium speciation calculations indicated that natural organic matter (NOM) complexes dominated Fe(III) speciation in agreement with that obtained by Donnan dialysis. In the case of Fe(II), however, the free cation was predicted to dominate under thermodynamic equilibrium, whilst our results indicated that Fe(II) was mainly present as neutral or negatively-charged complexes (most likely with sulfate). For all other divalent metals thermodynamic equilibrium speciation calculations agreed well with the Donnan dialysis results. The proportion of Al and REEs predicted to be negatively-charged was also grossly underestimated, relative to the experimental results, highlighting possible inaccuracies in the stability constants developed for these trivalent Me(SO{sub 4}){sub 2}{sup −} and/or Me–NOM complexes and difficulties in modeling complex environmental samples. These results will help improve metal mobility and toxicity models developed for CLASS-affected environments, and also demonstrate that Australian CLASS environments can discharge REEs at concentrations an order of magnitude greater than previously reported. - Highlights: • CLASS discharge large amounts of metals and their speciation is poorly

Rare earths in the Leadville Limestone and its marble derivates

International Nuclear Information System (INIS)

Jarvis, J.C.; Wildeman, T.R.; Banks, N.G.

1975-01-01

Samples of unaltered and metamorphosed Leadville Limestone (Mississippian, Colorado) were analyzed by neutron activation for ten rare-earth elements (REE). The total abundance of the REE in the least-altered limestone is 4-12 ppm, and their distribution patterns are believed to be dominated by the carbonate minerals. The abundances of the REE in the marbles and their sedimentary precursors are comparable but the distribution patterns are not. Eu is enriched over the other REE in the marbles, and stratigraphically upward in the formation (samples located progressively further from the heat source), the light REE become less enriched relative to the heavy REE. The Eu anomaly is attributed to its ability, unique among the REE, to change from the 3+ to 2+ oxidation state. Whether this results in preferential mobilization of the other REE or whether this reflects the composition of the pore fluid during metamorphism is unknown. Stratigraphically selective depletion of the heavy REE may be attributed to more competition for the REE between fluid and carbonate minerals in the lower strata relative to the upper strata. This competition could have been caused by changes in the temperature of the pore fluid or to the greater resistance to solution of the dolomite in the lower parts of the formation than the calcite in the upper parts

Signatures of geochemical changes at methane-seeps as recorded by seep carbonates

OpenAIRE

Himmler, Tobias

2011-01-01

This thesis compiles three manuscripts: (1) The first manuscript (chapter 2.1) contains petrographic and geochemical data of aragonitic seep carbonates from the Makran accretionary prism. High-resolution rare earth element (REE) analysis yield distinct total REE[aragonite] concentrations and shale-normalised REE[aragonite] patterns. The REE variations are ascribed to different pore fluid compositions and accompanied redox changes during aragonite precipitation. (2) The second manuscript (chap...

Alteration of Eudialyte and implications for the REE, ZR, and NB resources of the layered Kakortokites in the ILÍMAUSSAQ intrusion, South West Greenland

DEFF Research Database (Denmark)

Borst, Anouk Margaretha; Waight, Tod Earle; Smit, Matthijs Arjen

2014-01-01

The layered kakortokites in the southern part of the Ilímaussaq Intrusion are of great economic interest due to their high concentrations of REE, Zr, Nb and Ta. The prospective metals are largely contained in eudialyte, a complex sodium‐zirconosilicate and one of the major cumulus phases. Eudialyte...

Distribución de tierras raras en soluciones y coloides de un sistema natural de aguas ácidas (Arroyo del Val, Zaragoza

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López Julián, P. L.

1993-04-01

Full Text Available Acidic waters of the «Arroyo del Val» stream are naturally generated by oxidation of sulfide minerals dispersed in the sedimentary materials of the drainage basin. Mixing of this acidic stream with neutral-alkaline tributaries yields spectacular iron and aluminium rich flocculants that precipitate at the confluences. Previous analysis of rare earth element (REE concentrations of sorne 0.1 I-tm-filtered water samples and colloids are shown. The shale-normalized REE patterns of acidic waters show significant HREE enrichments in terms of Lun/Lan (≈ 2 and they are tipically enriched in the intermediate REEs (IREEs, Eu-Gd-Tb. So, in detail, these patterns are characterized by HREE enrichments between La and Gd and HREE depletions between Gd and Lu. The REE contents of two colloid samples are enriched by 103_104 relative to acidic waterso Different REE patterns were found in these colloids, sampled at differents distances from head of Arroyo del Val stream. Colloid sampled between the acidic waters analysed (CV-l shows a very similar REE pattern to those of the waters. The REE composition normalized to shale of second colloid sample (CV-2, collected down stream, has a flatter profile although it is still slightly convexo Significant REE removal (about 50 % caused by colloid coagulation is observed at the confluence and mixing point of the Arroyo del Val acidic waters with the first alkaline tributary. At this point the CV-l colloid sample shows HREE enrichment relative to acidic waters.El Arroyo del Val (provincia de Zaragoza constituye un curso de aguas ácidas de origen natural, generadas por el lavado de los materiales paleozoicos que atraviesa (Formación Bádenas, ricos en sulfuros metálicos dispersos. En los puntos de confluencia de este arroyo con afluentes de aguas neutras-alcalinas se producen espectaculares procesos de floculación de coloides ricos en aluminio y hierro que tapizan el fondo del arroyo. En este trabajo se

Gastric cancers of Western European and African patients show different patterns of genomic instability

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Mulder Chris JJ

2011-01-01

Full Text Available Abstract Background Infection with H. pylori is important in the etiology of gastric cancer. Gastric cancer is infrequent in Africa, despite high frequencies of H. pylori infection, referred to as the African enigma. Variation in environmental and host factors influencing gastric cancer risk between different populations have been reported but little is known about the biological differences between gastric cancers from different geographic locations. We aim to study genomic instability patterns of gastric cancers obtained from patients from United Kingdom (UK and South Africa (SA, in an attempt to support the African enigma hypothesis at the biological level. Methods DNA was isolated from 67 gastric adenocarcinomas, 33 UK patients, 9 Caucasian SA patients and 25 native SA patients. Microsatellite instability and chromosomal instability were analyzed by PCR and microarray comparative genomic hybridization, respectively. Data was analyzed by supervised univariate and multivariate analyses as well as unsupervised hierarchical cluster analysis. Results Tumors from Caucasian and native SA patients showed significantly more microsatellite instable tumors (p Conclusions Gastric cancers from SA and UK patients show differences in genetic instability patterns, indicating possible different biological mechanisms in patients from different geographical origin. This is of future clinical relevance for stratification of gastric cancer therapy.

Rare earth element patterns of the Central Indian Basin sediments related to their lithology

Digital Repository Service at National Institute of Oceanography (India)

Nath, B.N.; Roelandts, I.; Sudhakar, M.; Pluger, W.L.

Rare earth element (REE) concentration have been determined in terrigenous, siliceous (nodule barren and nodule bearing), calcareous, and red clay from the Central Indian Basin. The bulk distribution of REE, and in particular the relative cerium...

Nutritional status and dietary patterns in disabled people.

Science.gov (United States)

Bertoli, S; Battezzati, A; Merati, G; Margonato, V; Maggioni, M; Testolin, G; Veicsteinas, A

2006-03-01

Obesity, cardiovascular diseases, diabetes and osteoporosis are the most frequent pathologies among people with a severe reduction of physical activity. The impairment in nutritional status, consequent to quantitative and qualitative inadequacy of diet, could be one of the first steps in the development of co-morbidities in disabled subjects. In order to evaluate this hypothesis we investigated the nutritional status and the food intake in patients with physical or mental disabilities. Thirty-seven disabled subjects (24 with exclusively physical inactivity and 13 with mental retardation and physical inactivity) mean age 33.5+/-9.2 years and 25 healthy subjects (mean age 31.0+/-9.3 years) were enrolled. Anthropometric measurements, indirect calorimetry, dual-energy X-ray absorptiometry, dietary intake and biochemical parameters were collected for each subject. Forty percent of disabled were overweight and 14% were obese. Fat free mass (FFM) and bone mineral content (BMC) was lower and fat mass (FM) was higher than able-bodied control. Absolute resting energy expenditure (REE) was lower in disabled subjects, but this difference disappeared when REE was normalized to FFM. Dietary intake resulted unbalanced (16%, 31%, 50% of total daily energy intake derived from protein, lipid and carbohydrate respectively) with a distribution of dietary fatty acid quite far from the recommended ratio [3.1(SFA):4.1(MUFA):1.0(PUFA)] and an excessive consumption of simple carbohydrates (mean intake 17.5+/-4.9%). Insufficient intake of fibre, iron, calcium, potassium and zinc was also found. Finally, alterations in the cholesterol profile were evident in more than one third of the disabled subjects, whereas fasting glucose intolerance was evident in one fourth. This study shows a consistent nutritional status impairment in disabled patients resulting in an reduction of FFM and BMC, in an over-representation of FM and in a number of biochemical risk factors for cardiovascular disease. The

Geochemical characteristics of mafic and ultramafic rocks from the Naga Hills Ophiolite, India: Implications for petrogenesis

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Ajoy Dey

2018-03-01

Full Text Available The Naga Hills Ophiolite (NHO represents one of the fragments of Tethyan oceanic crust in the Himalayan Orogenic system which is exposed in the Phek and Kiphire districts of Nagaland, India. The NHO is composed of partially serpentinized dunite, peridotite, gabbro, basalt, minor plagiogranite, diorite dyke and marine sediments. The basalts are mainly composed of fine grained plagioclase feldspar, clinopyroxene and orthopyroxene and show quenching and variolitic textures. The gabbros are characterized by medium to coarse grained plagioclase, orthopyroxene and clinopyroxene with ophitic to sub-ophitic textures. The ultramafic cumulates are represented by olivine, Cpx and Opx. Geochemically, the basalts and gabbros are sub-alkaline to alkaline and show tholeiitic features. The basalts are characterized by 44.1–45.6 wt.% of SiO2 with 28–38 of Mg#, and the gabbros by 38.7–43.7 wt.% of SiO2, and 26–79 of Mg#. The ultramafic rocks are characterized by 37.4–52.2 wt.% of SiO2, and 80–88 of Mg#. In multi-element diagrams (spidergrams both basalts and gabbros show fractionated trends with strong negative anomalies of Zr, Nb, Sr and a gentle negative anomaly of P. However, the rare earth element (REE plots of the basalts and gabbros show two distinct patterns. The first pattern, represented by light REE (LREE depletion, suggests N-MORB features and can be interpreted as a signature of Paleo-Tethyan oceanic crust. The second pattern, represented by LREE enrichment with negligible negative Eu anomaly, conforms to E-MORB, and may be related to an arc tectonic setting. In V vs. Ti/1000, Cr vs. Y and AFM diagrams, the basalts and gabbros plot within Island Arc Tholeiite (IAT and MORB fields suggesting both ridge and arc related settings. The ultramafic rocks exhibit two distinct patterns both in spidergrams and in REE plots. In the spidergram, one group displays highly enriched pattern, whereas the other group shows near flat pattern compared

Identification of hydrologic and geochemical pathways using high frequency sampling, REE aqueous sampling and soil characterization at Koiliaris Critical Zone Observatory, Crete

Energy Technology Data Exchange (ETDEWEB)

Moraetis, Daniel, E-mail: moraetis@mred.tuc.gr [Department of Environmental Engineering, Technical University of Crete, 73100 Chania (Greece); Stamati, Fotini; Kotronakis, Manolis; Fragia, Tasoula; Paranychnianakis, Nikolaos; Nikolaidis, Nikolaos P. [Department of Environmental Engineering, Technical University of Crete, 73100 Chania (Greece)

2011-06-15

Highlights: > Identification of hydrological and geochemical pathways within a complex watershed. > Water increased N-NO{sub 3} concentration and E.C. values during flash flood events. > Soil degradation and impact on water infiltration within the Koiliaris watershed. > Analysis of Rare Earth Elements in water bodies for identification of karstic water. - Abstract: Koiliaris River watershed is a Critical Zone Observatory that represents severely degraded soils due to intensive agricultural activities and biophysical factors. It has typical Mediterranean soils under the imminent threat of desertification which is expected to intensify due to projected climate change. High frequency hydro-chemical monitoring with targeted sampling for Rare Earth Elements (REE) analysis of different water bodies and geochemical characterization of soils were used for the identification of hydrologic and geochemical pathways. The high frequency monitoring of water chemical data highlighted the chemical alterations of water in Koiliaris River during flash flood events. Soil physical and chemical characterization surveys were used to identify erodibility patterns within the watershed and the influence of soils on surface and ground water chemistry. The methodology presented can be used to identify the impacts of degraded soils to surface and ground water quality as well as in the design of methods to minimize the impacts of land use practices.

A study on mineralization U,REE and related processes in anomaly No.6 Khoshomy area central Iran

International Nuclear Information System (INIS)

Heidaryan, F.

2005-01-01

Uranium mineralization in Khoshomy prospect, located in central. part of Iran, with 303-15000 (cps) and 14 to 4000 (ppm) released, The main rock types include: gneiss, granite, pegmatite and migmatite, that influenced by pegmatite-albitic vines (quartz-heldespatic). Acidic and basic dykes, granodioritic, units and dolomite and marble have been seen. The alteration associated with the mineralization is potassic, argillic, propylitic, carbonization, silisificaition and hematitizaition. Uranium mineralization occurred in a hydrothermal phase with Cu, Mo, Ni and Au elements. Uranium primary minerals include pitchblende, coffinite, uraninite; and uranium secondary minerals include uranophane and . boltwoodite. REE mineralization occurred by the potassic phase in peginatitization process

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

Science.gov (United States)

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

2016-03-15

Donnan dialysis has been applied to forty filtered drainage waters collected from five coastal lowland acid sulfate soil (CLASS) catchments across north-eastern NSW, Australia. Despite having average pH values70%) as negatively-charged complexes. In contrast, the speciation of the divalent trace metals Co, Mn, Ni and Zn was dominated by positively-charged complexes and was strongly correlated with the alkaline earth metals Ca and Mg. Thermodynamic equilibrium speciation calculations indicated that natural organic matter (NOM) complexes dominated Fe(III) speciation in agreement with that obtained by Donnan dialysis. In the case of Fe(II), however, the free cation was predicted to dominate under thermodynamic equilibrium, whilst our results indicated that Fe(II) was mainly present as neutral or negatively-charged complexes (most likely with sulfate). For all other divalent metals thermodynamic equilibrium speciation calculations agreed well with the Donnan dialysis results. The proportion of Al and REEs predicted to be negatively-charged was also grossly underestimated, relative to the experimental results, highlighting possible inaccuracies in the stability constants developed for these trivalent Me(SO4)2(-) and/or Me-NOM complexes and difficulties in modeling complex environmental samples. These results will help improve metal mobility and toxicity models developed for CLASS-affected environments, and also demonstrate that Australian CLASS environments can discharge REEs at concentrations an order of magnitude greater than previously reported. Copyright © 2015 Elsevier B.V. All rights reserved.

Rare Earth Element Behavior During Incongruent Weathering and Varying Discharge Conditions in Silicate Dominated River Systems: The Australian Victorian Alps

Science.gov (United States)

Hagedorn, K. B.; Cartwright, I.

2008-12-01

The distribution of rare earth elements (REE) and trace elements was measured by ICP-MS on fresh, slightly weathered and weathered granite and surface water samples from a network of 11 pristine rivers draining the Australian Victorian Alps during (i) high and (ii) low discharge conditions. River water REE concentrations are largely derived from atmospheric precipitation (rain, snow), as indicated by similar Chondrite normalized REE patterns (higher LREE over HREE; negative Ce anomalies, positive Eu anomalies) and similar total REE concentrations during both dry and wet seasons. Calculations based on the covariance between REE and Cl concentrations and oxygen and hydrogen isotopes indicate precipitation input coupled with subsequent evaporation may account for 30% o 100% of dissolved REE in stream waters. The dissolved contribution to the granitic substratum to stream water comes mainly from the transformation of plagioclase to smectite, kaolinite and gibbsite and minor apatite dissolution. However, since most REE of the regional granite are present in accessory minerals (titanite, zircon, etc.) they do not significantly contribute to the river REE pool. REE concentrations drop sharply downstream as a result of dilution and chemical attenuation. A trend of downstream enrichment of the heavier REE is due to selective partitioning of the lighter REE (as both free REE or REECO3 complexes) to hydrous oxides of suspended Al which, in turn, is controlled by a downstream increase of pH to values > 6.1 (for free REE) and > 7.3 (for REECO3 complexes). Although most circumneutral waters were supersaturated with REE phosphate compounds, precipitation of LnPO4 is not believed to have been a dominant process because the predicted phosphate fractionation pattern is inconsistent with the observed trends. Negative saturation indices of hydrous ferric oxides also militate against surface complexation onto goethite. Instead, REE attenuation most likely resulted from adsorption onto

Rare earth element abundances in presolar SiC

Science.gov (United States)

Ireland, T. R.; Ávila, J. N.; Lugaro, M.; Cristallo, S.; Holden, P.; Lanc, P.; Nittler, L.; Alexander, C. M. O'D.; Gyngard, F.; Amari, S.

2018-01-01

Individual isotope abundances of Ba, lanthanides of the rare earth element (REE) group, and Hf have been determined in bulk samples of fine-grained silicon carbide (SiC) from the Murchison CM2 chondrite. The analytical protocol involved secondary ion mass spectrometry with combined high mass resolution and energy filtering to exclude REE oxide isobars and Si-C-O clusters from the peaks of interest. Relative sensitivity factors were determined through analysis of NIST SRM reference glasses (610 and 612) as well as a trace-element enriched SiC ceramic. When normalised to chondrite abundances, the presolar SiC REE pattern shows significant deficits at Eu and Yb, which are the most volatile of the REE. The pattern is very similar to that observed for Group III refractory inclusions. The SiC abundances were also normalised to s-process model predictions for the envelope compositions of low-mass (1.5-3 M⊙) AGB stars with close-to-solar metallicities (Z = 0.014 and 0.02). The overall trace element abundances (excluding Eu and Yb) appear consistent with the predicted s-process patterns. The depletions of Eu and Yb suggest that these elements remained in the gas phase during the condensation of SiC. The lack of depletion in some other moderately refractory elements (like Ba), and the presence of volatile elements (e.g. Xe) indicates that these elements were incorporated into SiC by other mechanisms, most likely ion implantation.

Mineralogy and chemical composition and distribution of rare earth elements of clay-rich sediments, Central Uganda

International Nuclear Information System (INIS)

Nyakairu, G.W.A.

2001-02-01

In Uganda, Precambrian rocks are extensively weathered to sediments, which are locally altered to form considerable clay deposits. Clay-rich sediment samples were collected from the Kajjansi, Kitiko, Kitetika, and Ntawo valleys (central Uganda), all of which are currently used for traditional brick, tile, and pottery manufacture. The mineralogical and chemical characteristics, and source rocks of these clay-rich sediments is not well understood. A study using modern analytical techniques, such as XRD, to obtain the bulk mineralogical composition, and XRF and INAA analyses for whole rock major and trace element abundances was performed. The results show that the sediments are dominated by kaolinite and quartz, and minor phases include smectite, chlorite, and illite/muscovite. Whole rock chemistry shows that sediment samples rich in SiO2 have low Al, Fe, Sc and Cr contents. The high chemical index of alteration (CIA) values (87 to 96), chemical index of weathering (CIW) values around 98 and low contents of the alkali and alkali earth elements of the clay-rich sediments suggest a relatively more intense weathering source area. The clay-rich sediments as raw materials for industry were classified as silty clays from grain size analysis. The chemical and mineralogical composition results show that, taken as a whole, the clay-rich sediments possess characteristics satisfactory for brick production. The chondrite-normalized rare earth elements (REE) patterns of the clay-rich sediments show LREE enrichments and a negative Eu anomaly. The high chondrite-normalized La/Yb ratios, and Gd/Yb ratios lower than 2.0, confirm that the sediments are enriched in the LREEs. The mineralogical composition, REE contents, and elemental ratios in these sediments suggest a provenance from mainly felsic rocks, with only minor contributions from basic sources. The basic sediments were most likely derived from metasedimentary rocks, such as muscovite-biotite schists, which are characteristic

High-precision analysis on annual variations of heavy metals, lead isotopes and rare earth elements in mangrove tree rings by inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Yu Kefu; Kamber, Balz S.; Lawrence, Michael G.; Greig, Alan; Zhao Jianxin

2007-01-01

Annual variations from 1982 to 1999 of a wide range of trace elements and reconnaissance Pb isotopes ( 207 Pb/ 206 Pb and 208 Pb/ 206 Pb) were analyzed by solution ICP-MS on digested ash from mangrove Rhizophora apiculata, obtained from Leizhou Peninsula, along northern coast of South China Sea. The concentrations of the majority of elements show a weak declining trend with growth from 1982 to 1999, punctuated by several high concentration spikes. The declining trends are positively correlated with ring width and negatively correlated with inferred water-use efficiency, suggesting a physiological control over metal-uptake in this species. The episodic metal concentration-peaks cannot be interpreted with lateral movement or growth activities and appear to be related to environmental pollution events. Pb isotope ratios for most samples plot along the 'Chinese Pb line' and clearly document the importance of gasoline Pb as a source of contaminant. Shale-normalised REE + Y patterns are relatively flat and consistent across the growth period, with all patterns showing a positive Ce anomaly and elevated Y/Ho ratio. The positive Ce anomaly is observed regardless of the choice of normaliser, in contrast to previously reported REE patterns for terrestrial and marine plants. This pilot study of trace element, REE + Y and Pb isotope distribution in mangrove tree rings indicates the potential use of mangroves as monitors of historical environmental change

Komatiites of the Onverwacht Group, S. Africa: REE geochemistry, Sm/Nd age and mantle evolution

Science.gov (United States)

Jahn, Bor-Ming; Gruau, G.; Glikson, A. Y.

1982-08-01

Komatiites of the Tjakastad Subgroup of the Onverwacht Group (S. Africa) were dated by the Sm/Nd method. A whole-rock isochron yields an age of 3.56±0.24 (2 σ) AE, with initial 143Nd/144Nd ratio of 0.50818±23 (2 σ), corresponding to ɛ Nd( T)= + 1.9±4.5. This age is interpreted as the time of initial Onverwacht volcanism. This result agrees with earlier Sm/Nd data of Hamilton et al. (1979) and is consistent with the Rb-Sr result of Jahn and Shih (1974). Komatiites may be divided into 3 groups based on the typology of heavy REE distributions (Jahn and Gruau 1981). According to this scheme, the Onverwacht komatiites of the present study belong to two groups: the predominant Group II rocks showing (Gd/Yb)N≃1.4, CaO/Al2O3 = 1.33, Al2O3/TiO2≃10.6; and the subordinate Group III rocks with (Gd/Yb)Nconnotation of the chemical parameters, such as CaO/Al2O3, (Gd/Yb)N or Al2O3/TiO2 ratio has not been firmly established. The characteristic “high” CaO/Al2O3 or (Gd/Yb)N ratios in many Onverwacht Group rocks can also be explained as a result of local short-term mantle heterogeneity.

Speciation of rare earth elements in different types of soils in China

International Nuclear Information System (INIS)

Wang Lijun; Zhang Shen; Gao Xiaojiang; Liu Shujuan

1997-01-01

Contents, distribution patterns, physical and chemical speciation of rare earth elements (REEs) in laterite (tropical zone), red earth (middle subtripical earth), yellow brown soil (Northern subtripical earth), cinnamon soil (warm temperature zone), leached chernozem (temperate zone) and albic bleached soil (temperate zone) in China were determined with instrumental neutron activation analysis (INAA). Content and distribution patterns of ERRs are closely related to soil mechanical composition. In laterite, red earth, yellow brown soil and leached chernozem, REEs mainly enrich in fine grain particles or coarser grain partials while in clay particles no such enrichment was found. The distribution patterns of REEs in these soils are consistent with the REE features of their parent rocks. In all the six soils, REEs mainly exist in residual form, and with the increase of atomic number, intermediate REEs (IRRE) have lower proportions of residual form than light REEs (LREE) and heavy REEs (HREE). For the six unstable forms, water soluble form has the lowest proportion. The proportions of exchangeable form, carbonate and specific adsorption form are lower. The proportions of Fe-Min oxides form in different types of soils decrease gradually from Southern China to Northern China following the order: laterite > red earth > yellow brown soil > cinnamon soil, leached chernozem, albic bleached soil. Proportions of bound organic matters are higher and follow the order: Albic bleached soil > leached chernozem > red earth > laterite > yellow brown soil > cinnamon soil. The albic bleached soil has higher proportion of softly bound organic matter form. The leached chernozem has higher proportion of tightly bound organic matter form. Form of bound to organic matter in laterite is almost totally made up of form of softly bound to organic matter

Origin of heavy REE mineralisation in carbonatites: Constraints form the Huanglongpu Mo-HREE deposit, Qinling, China.

Science.gov (United States)

Smith, Martin; Cheng, Xu; Kynicky, Jindrich; Cangelosi, Delia; Wenlei, Song

2017-04-01

The carbonatite dykes of the Huanglongpu area, Lesser Qinling, China, are unusual in that they are quartz-bearing, Mo-mineralised and enriched in the heavy rare earth elements (HREE) relative to typical carbonatites. Carbonatite monazite (208.9±4.6 Ma to 213.6±4.0; Song et al., 2016) gives a comparable U-Pb radiometric age to molybdenite (220Ma; Stein et al., 1997), confirming interpretations that Mo is derived from the carbonatite, and not a subsequent overprint from regional porphyry-style mineralisation ( 141Ma). The sulphides in the carbonatites have mantle-like 34S ( 1‰) and low δ26Mg values (-1.89 to -1.07‰), similar to sedimentary carbonates, suggesting a recycled sediment contribution in their mantle sources that may be responsible for the Mo and HREE enrichment (Song et al., 2016). The textures of REE minerals indicate crystallisation of monazite-(Ce), bastnäsite-(Ce), parisite-(Ce) and aeschynite-(Ce) as magmatic phases. Monazite-(Ce) was subsequently altered to produce apatite, which was in turn replaced by britholite-(Ce), accompanied by the formation of allanite-(Ce). The REE-fluorcarbonates where replaced by synchysite-(Ce) and röntgenite-(Ce). Aeschynite-(Ce) was altered initially to uranopyrochlore and then pyrochlore with uraninite inclusions. The mineralogical evolution reflects the evolution from magmatic carbonatite, through to more silica-rich conditions during the magmatic-hydrothermal transition, to fully hydrothermal conditions accompanied by the formation of sulphate minerals. Each alteration stage resulted in the preferential leaching of the LREE and enrichment in the HREE. Mass balance considerations indicate that the HREE enrichment could not be a passive process, and that hydrothermal fluids must have contributed HREE to the system. The evolution of the fluorcarbonate mineral assemblage requires an increase in aCa2+ and aCO32- in the metasomatic fluid, and so breakdown of HREE-enriched calcite may have been the HREE source

Characterization of GmENOD40, a gene showing novel patterns of cell-specific expression during soybean nodule development.

NARCIS (Netherlands)

Yang, W.C.; Katinakis, P.; Hendriks, P.; Smolders, A.; Vries, de F.; Spee, J.; Kammen, van A.; Bisseling, T.; Franssen, H.

1993-01-01

In this paper, the soybean 'early nodulin' clone pGmENOD40 is characterized. The GmENOD40 encoded protein does not contain methionine and does not show homology to proteins identified so far. In situ hybridizations showed that this gene has a complex expression pattern during development of

Clay Mineralogy of Coal-Hosted Nb-Zr-REE-Ga Mineralized Beds from Late Permian Strata, Eastern Yunnan, SW China: Implications for Paleotemperature and Origin of the Micro-Quartz

Directory of Open Access Journals (Sweden)

Lixin Zhao

2016-05-01

Full Text Available The clay mineralogy of pyroclastic Nb(Ta-Zr(Hf-REE-Ga mineralization in Late Permian coal-bearing strata from eastern Yunnan Province; southwest China was investigated in this study. Samples from XW and LK drill holes in this area were analyzed using XRD (X-ray diffraction and SEM (scanning electronic microscope. Results show that clay minerals in the Nb-Zr-REE-Ga mineralized samples are composed of mixed layer illite/smectite (I/S; kaolinite and berthierine. I/S is the major component among the clay assemblages. The source volcanic ashes controlled the modes of occurrence of the clay minerals. Volcanic ash-originated kaolinite and berthierine occur as vermicular and angular particles, respectively. I/S is confined to the matrix and is derived from illitization of smectite which was derived from the original volcanic ashes. Other types of clay minerals including I/S and berthierine precipitated from hydrothermal solutions were found within plant cells; and coexisting with angular berthierine and vermicular kaolinite. Inferred from the fact that most of the I/S is R1 ordered with one case of the R3 I/S; the paleo-diagenetic temperature could be up to 180 °C but mostly 100–160 °C. The micro-crystalline quartz grains (<10 µm closely associated with I/S were observed under SEM and were most likely the product of desiliconization during illitization of smectite.

Structure, Variation, and Co-occurrence of Soil Microbial Communities in Abandoned Sites of a Rare Earth Elements Mine.

Science.gov (United States)

Chao, Yuanqing; Liu, Wenshen; Chen, Yanmei; Chen, Wenhui; Zhao, Lihua; Ding, Qiaobei; Wang, Shizhong; Tang, Ye-Tao; Zhang, Tong; Qiu, Rong-Liang

2016-11-01

Mining activity for rare earth elements (REEs) has caused serious environmental pollution, particularly for soil ecosystems. However, the effects of REEs on soil microbiota are still poorly understood. In this study, soils were collected from abandoned sites of a REEs mine, and the structure, diversity, and co-occurrence patterns of soil microbiota were evaluated by Illumina high-throughput sequencing targeting 16S rRNA genes. Although microbiota developed significantly along with the natural restoration, the microbial structure on the site abandoned for 10 years still significantly differed from that on the unmined site. Potential plant growth promoting bacteria (PGPB) were identified by comparing 16S sequences against a self-constructed PGPB database via BLAST, and it was found that siderophore-producing and phosphorus-solubilizing bacteria were more abundant in the studied soils than in reference soils. Canonical correspondence analysis indicated that species richness of plant community was the prime factor affecting microbial structure, followed by limiting nutrients (total carbon and total nitrogen) and REEs content. Further co-occurring network analysis revealed nonrandom assembly patterns of microbiota in the studied soils. These results increase our understanding of microbial variation and assembly pattern during natural restoration in REE contaminated soils.

Pattern of neural responses to verbal fluency shows diagnostic specificity for schizophrenia and bipolar disorder

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Walshe Muriel

2011-01-01

Full Text Available Abstract Background Impairments in executive function and language processing are characteristic of both schizophrenia and bipolar disorder. Their functional neuroanatomy demonstrate features that are shared as well as specific to each disorder. Determining the distinct pattern of neural responses in schizophrenia and bipolar disorder may provide biomarkers for their diagnoses. Methods 104 participants underwent functional magnetic resonance imaging (fMRI scans while performing a phonological verbal fluency task. Subjects were 32 patients with schizophrenia in remission, 32 patients with bipolar disorder in an euthymic state, and 40 healthy volunteers. Neural responses to verbal fluency were examined in each group, and the diagnostic potential of the pattern of the neural responses was assessed with machine learning analysis. Results During the verbal fluency task, both patient groups showed increased activation in the anterior cingulate, left dorsolateral prefrontal cortex and right putamen as compared to healthy controls, as well as reduced deactivation of precuneus and posterior cingulate. The magnitude of activation was greatest in patients with schizophrenia, followed by patients with bipolar disorder and then healthy individuals. Additional recruitment in the right inferior frontal and right dorsolateral prefrontal cortices was observed in schizophrenia relative to both bipolar disorder and healthy subjects. The pattern of neural responses correctly identified individual patients with schizophrenia with an accuracy of 92%, and those with bipolar disorder with an accuracy of 79% in which mis-classification was typically of bipolar subjects as healthy controls. Conclusions In summary, both schizophrenia and bipolar disorder are associated with altered function in prefrontal, striatal and default mode networks, but the magnitude of this dysfunction is particularly marked in schizophrenia. The pattern of response to verbal fluency is highly

Using rare earth elements for the identification of the geographic origin of food

Science.gov (United States)

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

INAA analysis for Jun porcelaim and modern Chinese Jun porcelain

International Nuclear Information System (INIS)

Jia Xiuqin; Dong Jinquan; Han Song; Tang Yunhui

2004-01-01

A total of 28 old Jun porcelain, seven modern Chinese Jun porcelain and two Jingdezhen porcelain samples are analyzed with INAA method. The systematic geochemical study for these 37 samples on their REE and trace elements shows that these three types of china were made with relatively stable and similar material, although they leaptover 600 years in different colors and from different kilns. However, the REE patterns of modern Chinese Jun porcelain are a little bit different from that of old Jun porcelain, and clear different from the old glaze of Jindezheng. (authors)

Behavior of rare earth elements in coexisting manganese macronodules, micronodules, and sediments from the central Indian Basin

Digital Repository Service at National Institute of Oceanography (India)

Pattan, J.N.; Colley, S.; Higgs, N.C.

Associated manganese macronodules, micronodules, and sediments from the Central Indian Basin (CIB) were analyzed for major, trace, and rare earth elements (REE) to understand REE carrier phases and their fractionation pattern among three...

Uranium-lead dating of hydrothermal zircon and monazite from the Sin Quyen Fe-Cu-REE-Au-(U) deposit, northwestern Vietnam

Science.gov (United States)

Li, Xiao-Chun; Zhou, Mei-Fu; Chen, Wei Terry; Zhao, Xin-Fu; Tran, MyDung

2018-03-01

The Sin Quyen deposit in northwestern Vietnam contains economic concentrations of Cu, Au and LREE, and sub-economic concentration of U. In this deposit, massive and banded replacement ores are hosted in Neoproterozoic metapelite. The paragenetic sequence includes sodic alteration (stage I), calcic-potassic alteration and associated Fe-REE-(U) mineralization (stage II), Cu-Au mineralization (stage III), and sulfide-(quartz-carbonate) veins (stage IV). The Sin Quyen deposit experienced an extensive post-ore metamorphic overprint, which makes it difficult to precisely determine the mineralization age. In this study, zircon and monazite U-Pb geochronometers and the Rb-Sr isochron method are used to constrain the timing of mineralization. Zircon grains in the ore are closely intergrown or texturally associated with hydrothermal minerals of stage II (e.g., garnet, allanite, and hedenbergite). They may contain primary fluid inclusions and display irregular zoning in cathodoluminescence (CL) images. Zircon grains are rich in U (688 to 2902 ppm) and poor in Th (0.2 to 2.9 ppm). Their δ18OV-SMOW values range from 11.9 to 14.0‰, higher than those of typical magmatic zircon. These textural and compositional features imply that zircon precipitated from 18O- and U-rich hydrothermal fluids, coeval with the minerals of stage II. Monazite occurs in close association with stage II magnetite and allanite and has low contents of Th (<2700 ppm), indicative of a hydrothermal origin. Hydrothermal zircon and monazite have indistinguishable U-Pb ages of 841 ± 12 and 836 ± 18 Ma, respectively, representing the timing of Fe-REE mineralization. There is no direct isotopic constraint on the timing of the Cu-Au mineralization, but geological observations suggest that the Cu-Au and Fe-REE ores most likely formed within a single evolved hydrothermal process. In the plot of 87Rb/86Sr vs. 87Sr/86Sr, the composition of bulk-ore and biotite separates from ore lie along a reference line for 30 Ma

Development of a versatile sample preparation method and its application for rare-earth pattern and Nd isotope ratio analysis in nuclear forensics

International Nuclear Information System (INIS)

Krajko, J.

2015-01-01

An improved sample preparation procedure for trace-levels of lanthanides in uranium-bearing samples was developed. The method involves a simple co-precipitation using Fe(III) carrier in ammonium carbonate medium to remove the uranium matrix. The procedure is an effective initial pre-concentration step for the subsequent extraction chromatographic separations. The applicability of the method was demonstrated by the measurement of REE pattern and 143 Nd/ 144 Nd isotope ratio in uranium ore concentrate samples. (author)

Rare earth elements in the phosphatic-enriched sediment of the Peru shelf

Science.gov (United States)

Piper, D.Z.; Baedecker, P.A.; Crock, J.G.; Burnett, W.C.; Loebner, B.J.

1988-01-01

Apatite-enriched materials from the Peru shelf have been analyzed for their major oxide and rare earth element (REE) concentrations. The samples consist of (1) the fine fraction of sediment, mostly clay material, (2) phosphatic pellets and fish debris, which are dispersed throughout the fine-grained sediment, (3) tabular-shaped phosphatic crusts, which occur within the uppermost few centimeters of sediment, and (4) phosphatic nodules, which occur on the seafloor. The bulk REE concentrations of the concretions suggest that these elements are partitioned between the enclosed detrital material and the apatite fraction. Analysis of the fine-grained sediment with which the samples are associated suggested that this detrital fraction in the concretions should have shale REE values; the analysis of the fish debris suggested that the apatite fraction might have seawater values. The seawater contribution of REE's is negligible in the nodules and crust, in which the apatite occurs as a fine-grained interstitial cement. That is, the concentration of REE's and the REE patterns are predominantly a function of the amount of enclosed fine-grained sediment. By contrast, the REE pattern of the pelletal apatite suggests a seawater source and the absolute REE concentrations are relatively high. The REE P2O5 ratios of the apatite fraction of these samples thus vary from approximately zero (in the case of the crust and nodules) to as much as approximately 1.2 ?? 10-3 (in the case of the pellets). The range of this ratio suggests that rather subtle variations in the depositional environment might cause a significant variation in the REE content of this authigenic fraction of the sediment. Pelletal glauconite was also recovered from one sediment core. Its REE concentrations closely resemble those of the fish debris. ?? 1988.

Traumatic ulcerative granuloma with stromal eosinophilia of the palate showing an angiocentric/angiodestructive growth pattern

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Bernardo Ferreira Brasileiro

2012-01-01

Full Text Available Traumatic ulcerative granuloma with stromal eosinophilia (TUGSE is a benign, self-limiting lesion of the oral mucosa with unknown pathogenesis. A 65-year-old male patient presented with an ulcerative palate lesion, which on microscopic examination exhibited an exuberant polymorphic lymphoid proliferation, numerous eosinophils, and extensive vascular destruction. The atypical lymphoid cells infiltrating the medium-sized vessels showed positivity for CD3, CD30, and granzyme B, implicating an activated cytotoxic T-cell phenotype. The lesion diagnosed as TUGSE achieved complete resolution within 3 months. This unusual presentation has expanded the spectrum of oral CD30+ T-cell atypical infiltrates and must be distinguished from lymphomas showing angiocentric/angiodestructive growth pattern.

Intraspecific Arabidopsis hybrids show different patterns of heterosis despite the close relatedness of the parental genomes.

Science.gov (United States)

Groszmann, Michael; Gonzalez-Bayon, Rebeca; Greaves, Ian K; Wang, Li; Huen, Amanda K; Peacock, W James; Dennis, Elizabeth S

2014-09-01

Heterosis is important for agriculture; however, little is known about the mechanisms driving hybrid vigor. Ultimately, heterosis depends on the interactions of specific alleles and epialleles provided by the parents, which is why hybrids can exhibit different levels of heterosis, even within the same species. We characterize the development of several intraspecific Arabidopsis (Arabidopsis thaliana) F1 hybrids that show different levels of heterosis at maturity. We identify several phases of heterosis beginning during embryogenesis and culminating in a final phase of vegetative maturity and seed production. During each phase, the hybrids show different levels and patterns of growth, despite the close relatedness of the parents. For instance, during the vegetative phases, the hybrids develop larger leaves than the parents to varied extents, and they do so by exploiting increases in cell size and cell numbers in different ratios. Consistent with this finding, we observed changes in the expression of genes known to regulate leaf size in developing rosettes of the hybrids, with the patterns of altered expression differing between combinations. The data show that heterosis is dependent on changes in development throughout the growth cycle of the hybrid, with the traits of mature vegetative biomass and reproductive yield as cumulative outcomes of heterosis at different levels, tissues, and times of development. © 2014 American Society of Plant Biologists. All Rights Reserved.

Mineralogy and geochemistry of trace and Rare Earth Element from the Manaila massive sulphide deposit (Eastern Carpathians, Romania)

Science.gov (United States)

Moldoveanu, S.; Iancu, O. G.; Kasper, H. U.

2012-04-01

Keywords: Eastern Carpathians, Mănăila deposit, REE, trace elements, pyrite The present paper deal with the mineralogy and trace elements geochemistry of sulphide deposits from Mănăila mine field located in NE area of Eastern Carpathians Mountains (Romania). The mineralization occurs within metamorphic rocks of Tulgheş terrane, part of Crystalline-Mezozoic zone of the Eastern Carpathians. The metamorphic rocks in Mănăila area consist of felsic metavolcanics rocks with quartzites and quartz-feldspathic rocks as prevailing types. The P-T metamorphic conditions are typical of greenschis facies with biotite and garnet (Mn-Grt) in mineral assemblage. The mineralogical study was performed using reflected light microscope and Scanning Electron Microscopy (SEM) methods. Thus, the both methods show that the main sulphides minerals are represented by pyrite and chalcopyrite, being followed by sphalerite, galena and little amount of Cu sulphosalts (tetrahedrite and bournonite) and also by gangue minerals (quartz and carbonates). Pyrite occurs as large euhedral to subhedral grains in quartz and small rounded inclusion in chalcopyrite. The trace elements analysis was achieved on whole-rock samples and involved the determination of REE, LIL (Rb, Ba, Sr) and HFS (Y, Zr, Hf, U, Th, Nb, Ta) by ICP-MS method. The concentration of LIL and HFS trace elements in mineralized rocks decrease as follows: Ba > Bi > As > Sb > Co > Ga > Ni > Cd. Even if the barium contents in Mănăila ore is high, baritina (BaSO4) was not identified throught the mineralogical analyses carried out so far. The total rare earth element content (REE) of the samples from Mănăila range from 26.84 to 246.46 ppm. Chondrite - normalized REE patterns of the mineralized rocks show that the LREE are enriched in relation to the HREE. Also a positive Ce anomalies and negative Eu anomalies are present. Y/Ho and Zr/Hf ratios are close to the chondritic ratios indicating Charge-and-Radius-Controlled (CHARAC

The rare earth elements in municipal solid waste incinerators ash and promising tools for their prospecting

Energy Technology Data Exchange (ETDEWEB)

Funari, Valerio, E-mail: valerio.funari@unibo.it [Dipartimento di Scienze Biologiche, Geologiche e Ambientali (BiGeA)—University of Bologna, Piazza di Porta San Donato 1, Bologna (Italy); Bokhari, Syed Nadeem Hussain [General and Analytical Chemistry—Montanuniversität Leoben, Franz-Josef-Str. 18, Leoben (Austria); Vigliotti, Luigi [Istituto di Scienze Marine (ISMAR-CNR)—National Research Council, Via Piero Gobetti 101, Bologna (Italy); Meisel, Thomas [General and Analytical Chemistry—Montanuniversität Leoben, Franz-Josef-Str. 18, Leoben (Austria); Braga, Roberto [Dipartimento di Scienze Biologiche, Geologiche e Ambientali (BiGeA)—University of Bologna, Piazza di Porta San Donato 1, Bologna (Italy)

2016-01-15

Highlights: • The REE concentrations of bottom and fly ashes from municipal incinerators are investigated. • First attempt toward discriminating the magnetic signature (susceptibility) of ashes from incinerators. • New methods and parameters for REE prospecting, which can be determined quickly and with limited costs, are provided. - Abstract: Bottom and fly ashes from Municipal Solid Waste Incinerators (MSWI) are hazardous products that present concern for their safe management. An attractive option to reduce their impact both on the environment and the financial commitment is turning MSWI ashes into secondary raw materials. In this study we present the REE content and distribution of bottom and fly ashes from MSWI after a highly effective digestion method and samples analysis by ICP–MS. The chondrite-normalised REE patterns of MSWI bottom and fly ash are comparable with that of crustal averages, suggesting a main geogenic source. Deviations from typical crustal pattern (e.g., Eu, Tb) disclose a contribution of likely anthropogenic provenance. The correlation with major elements indicates possible sources for REE and facilitates a preliminary resource assessment. Moreover, magnetic susceptibility measurements can be a useful prospecting method in urban ores made of MSWI ashes. The relationship between REE and some influencing parameters (e.g., Pricing Influence Factor) emphasises the importance of MSWI ash as alternative source of REE and the need of further efforts for REE recovery and purification from low concentrations but high flows waste.

Trace Element Abundances in Refractory Inclusions from Antarctic Micrometeorites

Science.gov (United States)

Greshake, A.; Hoppe, P.; Bischoff, A.

1995-09-01

Refractory inclusions are charcteristic components in carbonaceous chondrites. Therefore, refractory inclusions found in micrometeorites can give important hints about the relationship between micrometeorites and carbonaceous chondrites. So far, only a few inclusions were found in micrometeorites [1-4]. In this study we report the first trace element analysis of perovskite and fassaite found in micrometeorites. We studied two Antarctic micrometeorites by ASEM, EMP, and SIMS. The first particle is 120 micrometers in size mainly consisting of a fine-grained matrix of dehydrated former phyllosilikates that enclose a 5 micrometers sized perovskite [5]. The perovskite is surrounded by a 1 micrometers thick rim of ilmenite and contains up to 1.3 wt% FeO as determined by EMP. The trace element abundances were determined by SIMS following the procedure described by [6]. The REE pattern of the perovskite is shown in Fig. 1. The pattern is closely related to the Group II pattern with its typical depletion of the more refractory REEs [7]. It is also very similar to the REE abundances of perovskite from Murchison (CM) [8] and CH-chondrites [9]. This may indicate a relationship between this micrometeorite and components in carbonaceous chondrites. The second micrometeorite is 100 micrometers in size consisting of a fine-grained (20 micrometers across) and a coarse-grained (80 micrometers across) area. Both areas contain fassaite with different chemical compositions. The particle was previously analyzed by Lindstrom and Kloeck [1] without knowing the mineralogy. We carried out SIMS analysis of each area of the micrometeorite separately. The TEE patterns of these two areas are similar and show in general a Group III pattern (20-30x CI) in which the more refractory REEs are not fractionated. The negative Eu anomaly is much more apparent in the coarse-grained area and no Yb anomaly is apparent in one of the areas. This is the first CAI of a micrometeorite showing a Group III REE

Geochemical processes assessed by Rare Earth Elements fractionation at “Laguna Verde” acidic-sulphate crater lake (Azufral volcano, Colombia)

International Nuclear Information System (INIS)

Inguaggiato, Claudio; Burbano, Viviana; Rouwet, Dmitri; Garzón, Gustavo

2017-01-01

The geochemical behaviour of major elements, Fe, Al, Mn, and Rare Earth Elements (REE) was investigated in the “Laguna Verde” acidic crater lake of Azufral volcano (Colombia). The cold lake water (T close to 10 °C) is sulphate-dominated, due to absorption and oxidation of H_2S (pH 2.1–2.7, Eh 196–260 mV), and Na-enriched (Total Dissolved Solids 0.79 g L"−"1). The total amount of REE dissolved in the lake ranges from 3.3 to 9.1 ppb. The REE patterns normalized to the local rocks show a Light Rare Earth Elements (LREE) depletion quite constant in the 15 samples. Similar patterns were already found in the acidic sulphate springs of Nevado del Ruiz volcano-hydrothermal system, caused by the precipitation of alunite and jarosite, absorbing LREE and hence removing them from solution. Alunite and jarosite minerals are not oversaturated at chemical-physical conditions within the lake itself, but alunite becomes oversaturated for temperatures above ≈100 °C, reigning in the underlying hydrothermal system. Water temperatures close to 75 °C were found in the northern part of the lake. Coupling the distribution of REE in lake water (LREE depleted) and the saturation indexes, we suggest that the distribution of REE in the lake water is the result of the alunite precipitation in the northern part of the lake and/or in the deeper hydrothermal system. The acidic hydrothermal fluids mobilize the REE with contents up to ≈5 orders of magnitude higher than seawater; acidic-hydrothermal systems, such as acidic crater lakes, can hence be considered potential REE “reservoirs”. - Highlights: • Acidic crater lakes can be considered potential Rare Earth Elements reservoirs. • Alunite precipitation removes Light Rare Earth Elements. • Rare Earth Elements identify geochemical processes in volcano-hydrothermal systems.

Anthropogenic gadolinium anomalies and rare earth elements in the water of Atibaia River and Anhumas Creek, Southeast Brazil.

Science.gov (United States)

de Campos, Francisco Ferreira; Enzweiler, Jacinta

2016-05-01

The concentrations of rare earth elements (REE), measured in water samples from Atibaia River and its tributary Anhumas Creek, Brazil, present excess of dissolved gadolinium. Such anthropogenic anomalies of Gd in water, already described in other parts of the world, result from the use of stable and soluble Gd chelates as contrast agents in magnetic resonance imaging. Atibaia River constitutes the main water supply of Campinas Metropolitan area, and its basin receives wastewater effluents. The REE concentrations in water samples were determined in 0.22-μm pore size filtered samples, without and after preconcentration by solid-phase extraction with bis-(2-ethyl-hexyl)-phosphate. This preconcentration method was unable to retain the anthropogenic Gd quantitatively. The probable reason is that the Gd chelates dissociate slowly in acidic media to produce the free ion that is retained by the phosphate ester. Strong correlations between Gd and constituents or parameters associated with effluents confirmed the source of most Gd in water samples as anthropogenic. The shale-normalized REE patterns of Atibaia River and Anhumas Creek water samples showed light and heavy REE enrichment trends, respectively. Also, positive Ce anomalies in many Atibaia River samples, as well as the strong correlations of the REE (except Gd) with terrigenous elements, imply that inorganic colloidal particles contributed to the REE measured values.

Mobility of rare earth element in hydrothermal process and weathering product: a review

Science.gov (United States)

Lintjewas, L.; Setiawan, I.

2018-02-01

The Rare Earth Element (REE), consists of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Lu, Ho, Er, Tm, Yb, are important elements to be used as raw materials of advanced technology such as semiconductors, magnets, and lasers. The research of REE in Indonesia has not been done. Several researches were conducted on granitic rocks and weathering product such as Bangka, Sibolga, West Kalimantan, West Sulawesi and Papua. REE can be formed by hydrothermal processes such as Bayan Obo, South China. The REE study on active hydrothermal system (geothermal) in this case also has the potential to produce mineral deposits. The purpose of this review paper is to know the mobility of REE on hydrothermal process and weathering products. Mobility of REE in the hydrothermal process can change the distribution patterns and REE content such as Ce, Eu, La, Lu, Nd, Sm, and Y. Another process besides the hydrothermal is weathering process. REE mobility is influenced by weathering products, where the REE will experience residual and secondary enrichment processes in heavier minerals.

Rare earth element geochemistry of South Atlantic deep sea sediments: Ce anomaly change at approx. 54 My

International Nuclear Information System (INIS)

Wang, Y.L.; Liu, Y.-G.; Schmitt, R.A.; Oregon State Univ., Corvallis; Oregon State Univ., Corvallis; Oregon State Univ., Corvallis

1986-01-01

The geochemistry of the REE (rare earth elements) in oceanic sediments is discussed, based mainly on samples from DSDP Holes 530A and 530B, Leg 75, and Hole 525A, Leg 74. The proposed mechanisms for incorporation of the REE into the marine carbonate phases are adsorption, chiefly onto the carbonate minerals and on Sc, Hf, and Ta-rich FE-Mn hydroxide flocs as carbonate coatings. The Ce anomaly of marine carbonate was used as an indicator of paleo-ocean water redox conditions: the bottom water of the Angola Basin was in a reducing condition in the Cretaceous. At ca. 54 My, the South Atlantic water condition became oxidizing, similar to the present seawater redox condition. This change was related to the improvement of circulation due to the widening of South Atlantic and the subsidence of water circulation barriers such as the Walvis Ridge and perhaps the Romanche Fracture Zone. The REE abundances and patterns of younger sediments in the Angola Basin (YSAB) are very similar to those observed in NASC, PAAS, and ES sediments. The YSAB REE abundances and patterns may represent the average REE distribution of the exposed African continental crust. The strong resemblance of REE distributions of YSAB, NASC, PAAS and ES suggests thorough REE mixing from different sources and the uniformity of the average crustal compositions of different continents: Africa, North America, Australia, and Europe. (author)

Residual levels of rare earth elements in freshwater and marine fish and their health risk assessment from Shandong, China

International Nuclear Information System (INIS)

Yang, Luping; Wang, Xining; Nie, Hongqian; Shao, Lijun; Wang, Guoling; Liu, Yongjun

2016-01-01

The total concentrations of rare earth elements (ΣREE) were quantified in 251 samples from 10 common species of freshwater and marine fish in seventeen cities of Shandong, China. ΣREE obtained from the freshwater fish ranged from 34.0 to 37.9 ngg −1 (wet weight) and marine fish from 12.7 to 37.6 ngg −1 . The ratio of LREE to HREE was 13.7:1 and 10:1 for freshwater and marine fish, respectively. This suggests that freshwater fish exhibit greater REE concentrations than marine fish and the biological effects of LREE are higher than HREE. Results revealed a similar REE distribution pattern between those fish and coastal sediments, abiding the “abundance law”. The health risk assessment demonstrated the EDIs of REEs in fish were significantly lower than the ADI, indicating that the consumption of these fish presents little risk to human health. - Highlights: •Concentrations of rare earth elements in freshwater and marine fishes from the coastlines of Shandong, China are reported. •Statistical analysis and comparison indicates that freshwater fishes exhibit greater REE concentrations than marine fishes. •A similar REE distribution pattern was found between those of fish and coastal sediments, abiding the "abundance law". •Health risk assessment demonstrated that consuming fish is presently at little risk to human health.

Excess europium content in Precambrian sedimentary rocks and continental evolution

Science.gov (United States)

Jakes, P.; Taylor, S. R.

1974-01-01

It is proposed that the europium excess in Precambrian sedimentary rocks, relative to those of younger age, is derived from volcanic rocks of ancient island arcs, which were the source materials for the sediments. Precambrian sedimentary rocks and present-day volcanic rocks of island arcs have similar REE patterns, total REE abundances, and excess Eu, relative to the North American shale composite. The present upper crustal REE pattern, as exemplified by that of sediments, is depleted in Eu, relative to chondrites. This depletion is considered to be a consequence of development of a granodioritic upper crust by partial melting in the lower crust, which selectively retains europium.

Transport and transformation of riverine neodymium isotope and rare earth element signatures in high latitude estuaries: A case study from the Laptev Sea

Science.gov (United States)

Laukert, Georgi; Frank, Martin; Bauch, Dorothea; Hathorne, Ed C.; Gutjahr, Marcus; Janout, Markus; Hölemann, Jens

2017-11-01

Marine neodymium (Nd) isotope and rare earth element (REE) compositions are valuable tracers for present and past ocean circulation and continental inputs. Yet their supply via high latitude estuaries is largely unknown. Here we present a comprehensive dissolved Nd isotope (expressed as εNd values) and REE data set together with seawater stable oxygen isotope (δ18O) compositions of samples from the Laptev Sea recovered in two Arctic summers and one winter. The Laptev Sea is a shallow Siberian Shelf sea characterized by extensive river-runoff, sea-ice production and ice transport into the Arctic Ocean. The large variability in εNd (-6 to -17), REE concentrations (16 to 600 pmol/kg for Nd) and REE patterns is controlled by freshwater supply from distinct riverine sources and open ocean Arctic Atlantic Water. Strikingly and contrary to expectations, except for cerium no evidence for significant release of REEs from particulate phases is found, which is attributed to low amounts of suspended particulate matter and high dissolved organic carbon concentrations present in the contributing rivers. Essentially all shelf waters are depleted in light (L)REEs, while the distribution of the heavy REEs shows a deficiency at the surface and a pronounced excess in the bottom layer. This distribution is consistent with REE removal through coagulation of riverine nanoparticles and colloids starting at salinities near 10 and resulting in a drop of all REE concentrations by ∼30%. With increasing salinity preferential LREE removal is observable reaching ∼75% for Nd at a salinity of 34. Although the delayed onset of dissolved REE removal contrasts with most previous observations from other estuarine environments, it agrees remarkably well with results from recent experiments simulating estuarine mixing of seawater with organic-rich river waters. In addition, melting and formation of sea ice leads to further REE depletion at the surface and strong REE enrichment near the shelf

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

International Nuclear Information System (INIS)

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

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 species are very similar and resemble those in the surface water. The results of this study suggest that there is no significant fractionation between the REEs during their uptake by the plant roots from soil solution. However, the variation of the relative abundance of individual REE occurs in the process of transportation and deposition of REEs in plants. (author)

Interactions of trace elements with fracture filling minerals from the Aespoe Hard Rock Laboratory

International Nuclear Information System (INIS)

Landstroem, O.; Tullborg, E.L.

1995-06-01

This report focuses on the distribution of stable elements and natural radionuclides (e.g. REEs, Th, Ra, Sr and Cs) in natural fracture systems. They have been redistributed by natural processes in the past; mobilization, transport and deposition of which the latter is manifested as 'enrichments' of the elements in fracture fillings. Fillings dominated by Fe-oxyhydroxide, calcite and clay minerals show the highest concentrations. Precipitates from different fractures show large variations in concentration levels of trace elements, REE patterns, and activity and activity ratios of natural radionuclides, reflecting variations in physical, chemical and hydrological properties of the fractures. The incorporation of REEs, Sr, Th and U in calcite is significant. The precipitation rate influences the amount of Sr incorporated and probably other elements as well. Clay minerals have high sorption capacity and are important in the retention of Cs and Sr as well as of REEs, Th, U and Ra. The importance of clay minerals in radionuclide retention is emphasized by the results from this study, even small amounts of clay minerals in fractures and fracture zones can significantly influence the radionuclide migration. Accurate determination of quantities and types of clay minerals is therefore very important for radionuclide migration modelling. 58 refs, 14 figs, 12 tabs

Interactions of trace elements with fracture filling minerals from the Aespoe Hard Rock Laboratory

Energy Technology Data Exchange (ETDEWEB)

Landstroem, O [Studsvik Eco and Safety AB, Nykoeping (Sweden); Tullborg, E L [Terralogica AB (Sweden)

1995-06-01

This report focuses on the distribution of stable elements and natural radionuclides (e.g. REEs, Th, Ra, Sr and Cs) in natural fracture systems. They have been redistributed by natural processes in the past; mobilization, transport and deposition of which the latter is manifested as `enrichments` of the elements in fracture fillings. Fillings dominated by Fe-oxyhydroxide, calcite and clay minerals show the highest concentrations. Precipitates from different fractures show large variations in concentration levels of trace elements, REE patterns, and activity and activity ratios of natural radionuclides, reflecting variations in physical, chemical and hydrological properties of the fractures. The incorporation of REEs, Sr, Th and U in calcite is significant. The precipitation rate influences the amount of Sr incorporated and probably other elements as well. Clay minerals have high sorption capacity and are important in the retention of Cs and Sr as well as of REEs, Th, U and Ra. The importance of clay minerals in radionuclide retention is emphasized by the results from this study, even small amounts of clay minerals in fractures and fracture zones can significantly influence the radionuclide migration. Accurate determination of quantities and types of clay minerals is therefore very important for radionuclide migration modelling. 58 refs, 14 figs, 12 tabs.

Rare earth elements in the banded iron formation of the Griqualand West sequence, northern Cape Province, South Africa

International Nuclear Information System (INIS)

Horstmann, U.E.; Haelbich, I.W.; Cornell, D.H.

1990-01-01

The Proterozoic banded iron-formations (BIF) of the Griqualand West sequence of the Transvaal Supergroup in the northern Cape Province of South Africa have been investigated for their rare earth elements (REE) contents. Twenty three REE analyses were completed using an ICP-AES method. Despite diagenetic and metamorphic processes, it can be concluded from the so far available REE data that the conspicuous differences in REE patterns to those reported from elsewhere indicate the BIF of the Transvaal Supergroup to have originated in relative restricted parts or basins of the Precambrian ocean. 7 refs., 1 fig

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

Science.gov (United States)

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

2015-11-01

Rare earth elements (REE) were used to assess attenuation processes in a passive system for acid mine drainage treatment (Jales, Portugal). Hydrochemical parameters and REE contents in water, soils and sediments were obtained along the treatment system, after summer and winter. A decrease of REE contents in the water resulting from the interaction with limestone after summer occurs; in the wetlands REE are significantly released by the soil particles to the water. After winter, a higher water dynamics favors the AMD treatment effectiveness and performance since REE contents decrease along the system; La and Ce are preferentially sequestered by ochre sludge but released to the water in the wetlands, influencing the REE pattern of the creek water. Thus, REE fractionation occurs in the passive treatment systems and can be used as tracer to follow up and understand the geochemical processes that promote the remediation of AMD. Copyright © 2015 Elsevier Ltd. All rights reserved.

Adolescents with current major depressive disorder show dissimilar patterns of age-related differences in ACC and thalamus

Directory of Open Access Journals (Sweden)

Cindy C. Hagan

2015-01-01

Conclusions: The depressed adolescent brain shows dissimilar age-related and symptom-sensitive patterns of GMV differences compared with controls. The thalamus and ACC may comprise neural markers for detecting these effects in youth. Further investigations therefore need to take both age and level of current symptoms into account when disaggregating antecedent neural vulnerabilities for MDD from the effects of MDD on the developing brain.

Food pattern modeling shows that the 2010 Dietary Guidelines for sodium and potassium cannot be met simultaneously

Science.gov (United States)

Maillot, Matthieu; Monsivais, Pablo; Drewnowski, Adam

2013-01-01

The 2010 US Dietary Guidelines recommended limiting intake of sodium to 1500 mg/d for people older than 50 years, African Americans, and those suffering from chronic disease. The guidelines recommended that all other people consume less than 2300 mg sodium and 4700 mg of potassium per day. The theoretical feasibility of meeting the sodium and potassium guidelines while simultaneously maintaining nutritional adequacy of the diet was tested using food pattern modeling based on linear programming. Dietary data from the National Health and Nutrition Examination Survey 2001-2002 were used to create optimized food patterns for 6 age-sex groups. Linear programming models determined the boundary conditions for the potassium and sodium content of the modeled food patterns that would also be compatible with other nutrient goals. Linear programming models also sought to determine the amounts of sodium and potassium that both would be consistent with the ratio of Na to K of 0.49 and would cause the least deviation from the existing food habits. The 6 sets of food patterns were created before and after an across-the-board 10% reduction in sodium content of all foods in the Food and Nutrition Database for Dietary Studies. Modeling analyses showed that the 2010 Dietary Guidelines for sodium were incompatible with potassium guidelines and with nutritionally adequate diets, even after reducing the sodium content of all US foods by 10%. Feasibility studies should precede or accompany the issuing of dietary guidelines to the public. PMID:23507224

Differentiation history of small bodies in the solar system: the howardite and mesosiderite meteorite parent bodies

International Nuclear Information System (INIS)

Mittlefehldt, D.W.

1978-01-01

Mesosiderites and howardites are regolith samples of differentiated asteroids. Instrumental neutron activation analysis (INAA) data on whole rock howardites and mesosiderite silicates show that the composition of howardites and mesosiderites are similar, and intermediate between those of eucrites and diogenites. The mesosiderites Mincy, Lowicz and Veramin show an enrichment in light REE and have an REE pattern that is qualitatively similar to that in terrestrial basalts thought to have been formed by small degrees of partial melting. Attempts to model the REE abundances in these mesosiderites indicates that they most likely formed by approx. 2 to 4% partial melting of a source containing low abundances of the rare earths. Since numerous properties separate mesosiderite silicates from howardites, it is clear that they are not samples of a well-mixed regolith from a single parent body. If regolith stirring is efficient on small parent bodies, then mesosiderites and howardites originated on separate parent bodies. Rare earth element patterns give evidence for remelting and fractional crystallization of preexisting cumulates and sequential melting episodes. The mesosiderites appear to contain a slightly greater abundance of diogenite-like material and certainly contain a greater abundance of large olivine clasts. These observations suggest that the mesosiderite parent body crust was more complexly fractionated than the howardite parent body crust. The latter appears to have been dominated by quenched basalt flows

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

Science.gov (United States)

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

2008-12-01

In a semi-arid to arid country like Israel, all freshwater resources are under (over-) utilization. Particularly, the Golan Heights rank as one of the most important extraction areas of groundwater of good quality and quantity. Additionally the mountain range feed to a high degree the most important freshwater reservoir of Israel, the Sea of Galilee. Hence, knowing the sources and characters of the Golan Heights groundwater systems is an instantaneous demand regarding sustainable management and protection. Within the "German-Israeli-Jordanian-Palestinian Joint Research Program for the Sustainable Utilisation of Aquifer Systems", hundreds of water samples were taken from all over the Jordan-Dead Sea rift-system to understand groundwater flow-systems and salinisation. For that purpose, each sample was analysed for major and minor ions, rare earth elements including yttrium (REY) and stable isotopes of water (d18O, d2H). The REY distribution in groundwater is established during infiltration by the first water-rock interaction and consequently reflects the leachable components of sediments and rocks of the recharge area. In well- developed flow-systems, REY are adsorbed onto pore surfaces are in equilibrium with the percolating groundwater, even if the lithology changes (e.g. inter-aquifer flow). Thus, groundwater sampled from wells and springs still show the REY distribution pattern established in the recharge area. Since high temperatures do not occur in Golan Heights, d2H and d18O are less controlled by water-rock interaction than by climatic and geomorphological factors at the time of replenishment. Applying the REY signature as a grouping criterion of groundwaters, d18O vs. d2H plots yield a new dimension in interpreting isotope data. The combined use of hydrochemical and isotopic methods enabled us to contain the areas of replenishment and the flow-paths of all investigated groundwater in the Golan Heights. Despite location, salinity or temperature of spring or

Mineralogy of the rare earth elements

International Nuclear Information System (INIS)

Clark, A.M.

1984-01-01

This paper contains mineralogic properties of the rare earth elements (REE). Notes are given on total REE abundances, distribution patterns, and modes of occurrence. References are confined as far as possible to papers containing usable REE data. The minerals are grouped alphabetically within each major cationic group. The paper includes an alphabetic table of mineral names, chemical formulas, crystal system and section number. It functions as a handy entrance to the mineralogic and bibliographic paper. (G.J.P.)

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

Science.gov (United States)

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

2016-09-01

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

Satellite III non-coding RNAs show distinct and stress-specific patterns of induction

International Nuclear Information System (INIS)

Sengupta, Sonali; Parihar, Rashmi; Ganesh, Subramaniam

2009-01-01

The heat shock response in human cells is associated with the transcription of satellite III repeats (SatIII) located in the 9q12 locus. Upon induction, the SatIII transcripts remain associated with the locus and recruit several transcription and splicing factors to form the nuclear stress bodies (nSBs). The nSBs are thought to modulate epigenetic changes during the heat shock response. We demonstrate here that the nSBs are induced by a variety of stressors and show stress-specific patterns of induction. While the transcription factor HSF1 is required for the induction of SatIII locus by the stressors tested, its specific role in the transcriptional process appears to be stress dependent. Our results suggest the existence of multiple transcriptional loci for the SatIII transcripts and that their activation might depend upon the type of stressors. Thus, induction of SatIII transcripts appears to be a generic response to a variety of stress conditions.

Physico-chemical control on the REE minerals in chloritoid-grade metasediments from a single outcrop (Central Alps, Switzerland)

DEFF Research Database (Denmark)

Janots, Emilie; Berger, Alfons; Engi, Martin

2011-01-01

minerals record fluid/ rock interaction that occurred at different deformation stages. Arsenic concentrations in REE phosphates appear to reflect conditions of elevated oxygen fugacity. In cases where such conditions are not inherited from the sedimentary protolith, the oxidation reflects a hydrothermal......). Allanite formation is texturally coeval with apatite, chloritoid and xenotime, during the main tectono-metamorphic stage. Allanite formation implies significant mass transfer of Ca and P via a fluid phase, which is not clearly related to advective transport. In Ga06, elongate monazite grains have...... a detrital core rimmed by newly formed monazite. Significant arsenic contents are found in newly formed monazite, xenotime and apatite. Monazite texture and composition suggest (re)crystallization by pressure solution, at an oxygen fugacity sufficient to partly oxidize As, S, U, and Fe. Whether...

Recognition of the importance of geogenic sources in the content of metals in PM2.5 collected in the Mexico City Metropolitan Area.

Science.gov (United States)

Morton-Bermea, Ofelia; Garza-Galindo, Rodrigo; Hernández-Álvarez, Elizabeth; Amador-Muñoz, Omar; Garcia-Arreola, Maria Elena; Ordoñez-Godínez, Sara L; Beramendi-Orosco, Laura; Santos-Medina, Graciela L; Miranda, Javier; Rosas-Pérez, Irma

2018-01-17

The study of airborne metals in urban areas is relevant due to their toxic effects on human health and organisms. In this study, we analyzed metals including rare earth elements (REE) in particles smaller than 2.5 μm (PM 2.5 ), collected at five sites around the Mexico City Metropolitan Area (MCMA), during three periods in 2011: April (dry-warm season, DW), August (rainy season, R), and November (dry-cold season, DC). Principal component analysis allowed identifying factors related to geogenic sources and factors related to anthropogenic sources. The recognition of the high impact of geogenic sources in PM 2.5 is in agreement with the REE distribution patterns, which show similar behavior as those shown by igneous rocks, confirming the influence of the regional geogenic material. Metals associated to geogenic sources showed higher concentration (p  0.05) and no similar seasonal pattern among them. These unexpected results exposed outstanding information regarding the identification of different geogenic sources as the main contributors of metals in the atmospheric environment in the MCMA and highlighted the importance of meteorology in the spatial and seasonal metal patterns.

Pulmonary alveolar proteinosis versus exogenous lipoid pneumonia showing crazy-paving pattern: Comparison of their clinical features and high-resolution CT findings

Energy Technology Data Exchange (ETDEWEB)

Choi, Hei Kyung; Park, Chang Min; Goo, Jin Mo; Lee, Hyun Ju (Dept. of Radiology, Seoul National Univ. College of Medicine, and Inst. of Radiation Medicine, Seoul National Univ. Medical Research Center, Seoul (Korea)), e-mail: cmpark@radiol.snu.ac.kr

2010-05-15

Background: Although pulmonary alveolar proteinosis (PAP) and exogenous lipoid pneumonia (ELP) require different treatment strategies, both manifest as a crazy-paving pattern on CT and often have similar clinical manifestations and radiologic features. Purpose: To investigate the clinical features and high-resolution computed tomography (HRCT) findings of PAP and ELP showing the crazy-paving pattern. Material and Methods: The clinical features and HRCT findings of eight patients with pathologically proven PAP and six patients with pathologically proven ELP showing the crazy-paving pattern were retrospectively evaluated. Two radiologists analyzed the HRCT findings of PAP and ELP in consensus in terms of the presence, severity, and extent of illdefined centrilobular nodules, consolidations, ground-glass opacities (GGOs), reticulations, and the crazy-paving pattern. Results: With respect to the clinical features of these two diseases, all patients with ELP were retrospectively found to have a history of oil ingestion. In terms of the HRCT findings, ill-defined centrilobular nodules were seen in five of six patients (83%) with ELP, whereas they were not present in any patient with PAP (P=0.003). Consolidation was also more frequently present in patients with ELP (83%) than in those with PAP (11%), which was statistically different (P=0.0265). In terms of the severity and extent, the crazy-paving pattern and reticulations on HRCT were significantly more extensive and severe in patients with PAP than in those with ELP. Conclusion: PAP and ELP with the crazy-paving pattern have several distinctive characteristics with respect to their HRCT findings as well as history of oil ingestion, and can therefore be distinguished from one another

Neighborhood diversity of large trees shows independent species patterns in a mixed dipterocarp forest in Sri Lanka.

Science.gov (United States)

Punchi-Manage, Ruwan; Wiegand, Thorsten; Wiegand, Kerstin; Getzin, Stephan; Huth, Andreas; Gunatilleke, C V Savitri; Gunatilleke, I A U Nimal

2015-07-01

Interactions among neighboring individuals influence plant performance and should create spatial patterns in local community structure. In order to assess the role of large trees in generating spatial patterns in local species richness, we used the individual species-area relationship (ISAR) to evaluate the species richness of trees of different size classes (and dead trees) in circular neighborhoods with varying radius around large trees of different focal species. To reveal signals of species interactions, we compared the ISAR function of the individuals of focal species with that of randomly selected nearby locations. We expected that large trees should strongly affect the community structure of smaller trees in their neighborhood, but that these effects should fade away with increasing size class. Unexpectedly, we found that only few focal species showed signals of species interactions with trees of the different size classes and that this was less likely for less abundant focal species. However, the few and relatively weak departures from independence were consistent with expectations of the effect of competition for space and the dispersal syndrome on spatial patterns. A noisy signal of competition for space found for large trees built up gradually with increasing life stage; it was not yet present for large saplings but detectable for intermediates. Additionally, focal species with animal-dispersed seeds showed higher species richness in their neighborhood than those with gravity- and gyration-dispersed seeds. Our analysis across the entire ontogeny from recruits to large trees supports the hypothesis that stochastic effects dilute deterministic species interactions in highly diverse communities. Stochastic dilution is a consequence of the stochastic geometry of biodiversity in species-rich communities where the identities of the nearest neighbors of a given plant are largely unpredictable. While the outcome of local species interactions is governed for each

Biogeochemical distribution of rare earths and other trace elements in plants and soils

International Nuclear Information System (INIS)

Laul, J.C.; Weimer, W.C.; Rancitelli, L.A.

1977-01-01

The rare earth concentrations in vegetables (corn, potatoes, peas, and butternut squash) were found to be extremely low: 10 -8 g/g to 10 -10 g/g. The chondritic normalized vegetable REE patterns are fractionated, including a negative Eu anomaly, and behave as a smooth function of the REE ionic radii. These patterns may be governed by the geochemistry of accessory minerals in the host soils. The depletion factors for various elements by vegetables relative to bulk soils are approx. 10 -4 for REE, Hf, Ta, Th, and U; approx. 10 -3 for Al, As, Ba, Cr, Fe, Mn, Sc, Se, And Sr; approx. 10 -2 for Co, Cs, Na, Ni, and Sb; approx. 10 -1 for Rb; and approx. 1 for K, Zn, and Br

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

Science.gov (United States)

Apostolopoulos, Vasso

2013-10-01

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

Sediment Sources, Depositional Environment, and Diagenetic Alteration of the Marcellus Shale, Appalachian Basin, USA: Nd, Sr, Li and U Isotopic Constraints

Science.gov (United States)

Phan, T. T.; Capo, R. C.; Gardiner, J. B.; Stewart, B. W.

2017-12-01

The organic-rich Middle Devonian Marcellus Shale in the Appalachian Basin, eastern USA, is a major target of natural gas exploration. Constraints on local and regional sediment sources, depositional environments, and post-depositional processes are essential for understanding the evolution of the basin. In this study, multiple proxies, including trace metals, rare earth elements (REE), the Sm-Nd and Rb-Sr isotope systems, and U and Li isotopes were applied to bulk rocks and authigenic fractions of the Marcellus Shale and adjacent limestone/sandstone units from two locations separated by 400 km. The range of ɛNd values (-7.8 to -6.4 at 390 Ma) is consistent with a clastic sedimentary component derived from a well-mixed source of fluvial and eolian material of the Grenville orogenic belt. The Sm-Nd isotope system and bulk REE distributions appear to have been minimally affected by post-depositional processes, while the Rb-Sr isotope system shows evidence of limited post-depositional redistribution. While REE are primarily associated with silicate minerals (80-95%), REE patterns of sequentially extracted fractions reflect post-depositional alteration at the intergranular scale. Although the chemical index of alteration (CIA = 54 to 60) suggests the sediment source was not heavily weathered, Li isotope data are consistent with progressively increasing weathering of the source region during Marcellus Shale deposition. δ238U values in bulk shale and reduced phases (oxidizable fraction) are higher than those of modern seawater and upper crust. The isotopically heavy U accumulated in these authigenic phases can be explained by the precipitation of insoluble U in anoxic/euxinic bottom water. Unlike carbonate cement within the shale, the similarity between δ238U values and REE patterns of the limestone units and those of modern seawater indicates that the limestone formed under open ocean (oxic) conditions.

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

The trace and rare earth element characteristics for Kui (Th anomaly, Nb–Ta trough and less spiked patterns, flat REE trends) indicate derivation from a refractory mantle source affected by fluids derived from subduction. Distinct differences in trace and REE characteristics between Daba and Kui can be interpreted in terms ...

Cerium anomalies in the Paleo-Mesozoic pelagic sediments of the Tamba group, southwest Japan

International Nuclear Information System (INIS)

Musashino, Makoto

1994-01-01

The oceanic sediments of the Tamba group, a part of the Japanese Paleo-Mesozoic accretionary prism are geochemically examined. Based on XMA, INAA and XRF analyses, the following results were obtained. These oceanic sediments have various REE patterns which correspond to environmental change on the ocean floor. The REE pattern changes from negative Ce anomaly through LREE>HREE or MREE>LREE≥HREE pattern to positive Ce anomaly in ascending order. And each REE pattern indicates a corresponding sedimentary environment. Negative Ce anomaly indicates that chert was deposited under the influence of hydrothermal activity or diagenetic metal accumulation. Chert with a LREE>HREE or a MREE>LREE≥HREE pattern resemble the sediment with positive Ce anomaly, but the lack of Ce anomaly suggests a less oxic condition of diagenesis or less Ce content in the sea water. Positive Ce anomaly suggests that sediments accumulated at a very slow rate under oxic condition, where authigenic metal flux from sea water resulted in such an REE pattern. Cherts and siliceous shales with positive Ce anomaly are exclusively detected at the upper part of chert-siliceous shale sequences in all successions of the Tamba group. This suggests that sea water of the Panthalassa Ocean was, at least partially, enriched in Ce, resembling the modern Atlantic more than the modern Pacific Ocean. The following causes are considered. Riverine input from surrounding continents was substantial. Reductive regeneration of Ce from continental shelves was active. Ce depleted sea water did not enter from the other 'ocean'. (J.P.N.)

Geochemical characteristics of granitoids and related mafic granulites from the Pan-African Dahomeyide belt, southeastern Ghana

International Nuclear Information System (INIS)

Aidoo, F.

2012-07-01

The Dahorneyide orogenic belt marks the southeastern limit of the West Africa craton (WAC). The belt consists of three structural units which include the deformed eastern edge of the WAC with its cover rocks made up of the Togo and the Buern Structural Units (external nappes), a suture zone assemblage of mafic and ultramafic rocks, and granitoid gneiss-rnigmatite assemblages (east of the suture zone). Geochemical and petrographic characteristics of the granitoids from the external nappes and mafic and ultramafic granulites roeks from the suture zone have been studied with the objective of inferring their petrogenesis and tectonic setting in which they were formed. Twenty five (25) representative samples were selected for petrographic studies and fifteen samples for major and trace elements composition using ICP-AES and ICP-MS respectively. The granitoids gneisses are mainly biotite muscovite gneisses, migmatites and granodiorites made up of quartz (25-68%), biotite (7-30%), plagioclase (8-40%), muscovite (4-20%) with some few pyroxene, sericite and calcite observed in some oF the samples. Within these rocks is an amphibole rich gneiss composed of about 45% amphiboles. The granitoid gneisses contain SiO 2 content of 40.60-68.90 wt. % with low Mg# of 36-46. Geochernically, they are classified as I-type, mctaluminous to peraluminous, magnessian to ferroan, calcic to calc alkali granitoids. They exhibit fractionated REE patterns with (La/Sm) N = 1.80-5.85 and (La/Yb) N = 3.76-76.30, and negative to positive Eu anomalies (Eu/Eu*'' = 0.68-2.10. The primitive mantle-normalised, trace element patterns show that the granitoid gneisses are characterised by enrichment in LILE relative to HFSE and in LREE relative HREE. They display subduction-related trace element characteristics of positive Ba and negative Ti, Ta, Nb and Hf anomalies. The mafic granulites are composed of quartz (16-43%), hornblende (12-45%), plagioclase (13-23%), pyroxene (13-17%), garnet (4

Bilateral versus ipsilesional cortico-subcortical activity patterns in stroke show hemispheric dependence.

Science.gov (United States)

Vidal, Ana C; Banca, Paula; Pascoal, Augusto G; Cordeiro, Gustavo; Sargento-Freitas, João; Gouveia, Ana; Castelo-Branco, Miguel

2018-01-01

Background Understanding of interhemispheric interactions in stroke patients during motor control is an important clinical neuroscience quest that may provide important clues for neurorehabilitation. In stroke patients bilateral overactivation in both hemispheres has been interpreted as a poor prognostic indicator of functional recovery. In contrast, ipsilesional patterns have been linked with better motor outcomes. Aim We investigated the pathophysiology of hemispheric interactions during limb movement without and with contralateral restraint, to mimic the effects of constraint-induced movement therapy. We used neuroimaging to probe brain activity with such a movement-dependent interhemispheric modulation paradigm. Methods We used a functional magnetic resonance imaging block design during which the plegic/paretic upper limb was recruited/mobilized to perform unilateral arm elevation, as a function of presence versus absence of contralateral limb restriction (n = 20, with balanced left/right lesion sites). Results Analysis of 10 right hemispheric stroke participants yielded bilateral sensorimotor cortex activation in all movement phases in contrast with the unilateral dominance seen in the 10 left hemispheric stroke participants. Superimposition of contralateral restriction led to a prominent shift from activation to deactivation response patterns, in particular in cortical and basal ganglia motor areas in right hemispheric stroke. Left hemispheric stroke was, in general, characterized by reduced activation patterns, even in the absence of restriction, which induced additional cortical silencing. Conclusion The observed hemispheric-dependent activation/deactivation shifts is novel and these pathophysiological observations suggest short-term neuroplasticity that may be useful for hemisphere-tailored neurorehabilitation.

Co-residence patterns in hunter-gatherer societies show unique human social structure.

Science.gov (United States)

Hill, Kim R; Walker, Robert S; Bozicević, Miran; Eder, James; Headland, Thomas; Hewlett, Barry; Hurtado, A Magdalena; Marlowe, Frank; Wiessner, Polly; Wood, Brian

2011-03-11

Contemporary humans exhibit spectacular biological success derived from cumulative culture and cooperation. The origins of these traits may be related to our ancestral group structure. Because humans lived as foragers for 95% of our species' history, we analyzed co-residence patterns among 32 present-day foraging societies (total n = 5067 individuals, mean experienced band size = 28.2 adults). We found that hunter-gatherers display a unique social structure where (i) either sex may disperse or remain in their natal group, (ii) adult brothers and sisters often co-reside, and (iii) most individuals in residential groups are genetically unrelated. These patterns produce large interaction networks of unrelated adults and suggest that inclusive fitness cannot explain extensive cooperation in hunter-gatherer bands. However, large social networks may help to explain why humans evolved capacities for social learning that resulted in cumulative culture.

Human microRNA oncogenes and tumor suppressors show significantly different biological patterns: from functions to targets.

Directory of Open Access Journals (Sweden)

Dong Wang

Full Text Available MicroRNAs (miRNAs are small noncoding RNAs which play essential roles in many important biological processes. Therefore, their dysfunction is associated with a variety of human diseases, including cancer. Increasing evidence shows that miRNAs can act as oncogenes or tumor suppressors, and although there is great interest in research into these cancer-associated miRNAs, little is known about them. In this study, we performed a comprehensive analysis of putative human miRNA oncogenes and tumor suppressors. We found that miRNA oncogenes and tumor suppressors clearly show different patterns in function, evolutionary rate, expression, chromosome distribution, molecule size, free energy, transcription factors, and targets. For example, miRNA oncogenes are located mainly in the amplified regions in human cancers, whereas miRNA tumor suppressors are located mainly in the deleted regions. miRNA oncogenes tend to cleave target mRNAs more frequently than miRNA tumor suppressors. These results indicate that these two types of cancer-associated miRNAs play different roles in cancer formation and development. Moreover, the patterns identified here can discriminate novel miRNA oncogenes and tumor suppressors with a high degree of accuracy. This study represents the first large-scale bioinformatic analysis of human miRNA oncogenes and tumor suppressors. Our findings provide help for not only understanding of miRNAs in cancer but also for the specific identification of novel miRNAs as miRNA oncogenes and tumor suppressors. In addition, the data presented in this study will be valuable for the study of both miRNAs and cancer.

An overview of uranium, rare metal and REE mineralisation in the crystallines of Sonbhadra district, Uttar Pradesh, India

International Nuclear Information System (INIS)

Parihar, P.

2014-01-01

Uranium and REE mineralisation hosted by the Proterozoic migmatites and younger intrusives is identified over 350 km"2 in Son Valley area, Sonbhadra district, Uttar Pradesh, which forms the northwestern extension of Chotanagpur Granite Gneiss Complex (CGGC). The rocks exposed include banded gneisses and metasedimentary enclaves, overlain by the Mahakoshal supracrustals and sediments of the Vindhyan Supergroup in the north and Gondwana Supergroup in the south. The craton had undergone repeated rifting, giving rise to intracratonic rift basins for the development of cover rock sequences of arkosic to psammo-pelitic metasediments, which now occur as migmatites comprising pegmatoid leucosomes and biotite melanosomes and associated mesosomes. These intracratonic zones are parallel to the Lower Proterozoic Mahakoshal supracrustals. Anorogenic, rift related plutons of alkali granite of middle Proterozoic age are seen emplaced within Mahakoshal supracrustals, which at places like Kundabhati and Sonwani are episyenitised.

Rare earth elements in soil extracts by ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Tobler, L.; Furrer, V.; Wyttenbach, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Burger, M.; Jakob, A. [AC-Laboratorium Spiez (Switzerland)

1997-09-01

Three different horizons of a soil profile were extracted with water and with a complexing solution. 14 REEs were determined in the extracts. The distribution patterns obtained from the different horizons were rather similar and did not show the large fractionations observed between different plant species growing on this soil. (author) 2 figs., 1 ref.

Fertiliser characterisation: Major, trace and rare earth elements

International Nuclear Information System (INIS)

Otero, N.; Vitoria, L.; Soler, A.; Canals, A.

2005-01-01

In recent years, there has been increasing concern regarding the chemical impact of agricultural activities on the environment so it is necessary to identify contaminants, and/or characterise the sources of contamination. In this study, a comprehensive chemical characterisation of 27 fertilisers of different types used in Spain has been conducted; major, minor and trace elements were determined, including rare earth elements. Results show that compound fertilisers used for fertigation or foliar application have low content of heavy metals, whereas fertilisers used for basal and top dressing have the highest content of both REE and other heavy metals. REE patterns of fertilisers have been determined in order for them to be used as tracers of fertilisers in future environmental studies. Furthermore in this work REE patterns of fertilisers are used as tracers of the source of phosphate in compound fertilisers, distinguishing between phosphorite and carbonatite derived fertilisers. Fertilisers from carbonatites have higher contents of REE, Sr, Ba and Th whereas fertilisers from phosphorites have higher contents of metals of environmental concern, such as Cd, U and As; and the sum of the heavy metals is higher. Some of the analysed fertilisers have Cd concentrations that exceed maximum values established in some countries and can be expected to produce long-term soil accumulation. Furthermore, other elements such as U, As and Cr are 10-50 times higher in concentration than those of Cd, but there is no legislation regarding them, therefore it is necessary to regulate fertiliser compositions in order to achieve environmental protection of soils and waters

Biogeochemical distribution of rare earths and other trace elements in plants and soils

Energy Technology Data Exchange (ETDEWEB)

Laul, J C; Weimer, W C; Rancitelli, L A

1977-01-01

The rare earth concentrations in vegetables (corn, potatoes, peas, and butternut squash) were found to be extremely low: 10/sup -8/ g/g to 10/sup -10/ g/g. The chondritic normalized vegetable REE patterns are fractionated, including a negative Eu anomaly, and behave as a smooth function of the REE ionic radii. These patterns may be governed by the geochemistry of accessory minerals in the host soils. The depletion factors for various elements by vegetables relative to bulk soils are approx. 10/sup -4/ for REE, Hf, Ta, Th, and U; approx. 10/sup -3/ for Al, As, Ba, Cr, Fe, Mn, Sc, Se, And Sr; approx. 10/sup -2/ for Co, Cs, Na, Ni, and Sb; approx. 10/sup -1/ for Rb; and approx. 1 for K, Zn, and Br.

Una nova aproximació a la pobresa infantil. Aplicació de l'indicador europeu "reference budgets" a Catalunya per a àrees densament poblades

OpenAIRE

Cussó Parcerisas, Irene Maria

2017-01-01

Aquesta investigació presenta la construcció de pressupostos de referència – “reference budgets”, els quals il·lustren cistelles de béns i serveis per assolir un nivell de vida acceptable per a diferents tipologies de família en àrees densament poblades de Catalunya, prenent Barcelona com a ciutat de referència. Aquest nivell de vida acceptable reflecteix el mínim de recursos necessaris perquè les persones puguin desenvolupar les diverses posicions i rols socials pertinents. Per elaborar aque...

[Geochemical characteristics and sources of atmospheric particulates in Shanghai during dust storm event].

Science.gov (United States)

Qian, Peng; Zheng, Xiang-min; Zhou, Li-min

2013-05-01

Atmospheric particulates were sampled from three sampling sites of Putuo, Minhang and Qingpu Districts in Shanghai between Oct. , 2009 and Oct. , 2010. In addition, particulate samples were also collected from Nantong, Zhengzhou, Xi'an, and Beijing city where dust storm dust transported along during spring. Element compositions of atmospheric particulates were determined by XRF and ICP-MS. The concentrations of major and trace elements in atmospheric particulates from Putuo, Minhang and Qingpu Districts were similar, indicating their common source. The UCC standardization distribution map showed that the major element composition of dust storm samples was similar to that of loess in northwestern China, indicating that the dust storm dust was mainly derived from Western desert and partly from local area. The REE partition patterns of dust storm dusts among different cities along dust transport route were similar to each other, as well as to those of northern loess, which indicates that the dust storm samples may have the same material source as loess, which mainly comes from crust material. However, the REE partition patterns of non-dust storm particulates were different among the studied cities, and different from those of loess, which suggests that the non-dust storm samples may be mixed with non-crust source material, which is different from dust storm dust and loess. The major element composition and REE partition pattern are effective indicators for source tracing of dust storm dust.

African Dust Transport Captured by Rare Earth Elemental Concentrations in Coral Microatolls

Science.gov (United States)

Ouellette, G., Jr.; DeLong, K.; Herrmann, A.; Huang, C. Y.; Shen, C. C.

2017-12-01

Winds are integral components of the climate system; unfortunately, windsare also among the climate variables that are most difficult to study prior to the instrumentalrecord. Paleoclimatologists use sedimentary dust records (e.g., lake and ocean cores) tounderstand past wind circulation conditions; however, these types of records typically are notamenable to sub-annual interpretation due to their limited temporal resolution. Here wedeveloped a coral-based dust-wind proxy to overcome these temporal limitations by usingtrace (nmol/mol) rare earth elemental concentrations recorded in the skeletons of coralmicroatolls. The rare earth elements (REE; the lanthanides as well as scandium and yttrium)behave similarly in geologic and geochemical systems, and have served as useful proxies ofgeological processes in both deep and shallow time. Corals incorporate REE as they deposittheir exoskeletons that extend incrementally with time forming annual density band couplets.Coral microatolls grow at or near the sea surface, where coral REE concentrations are mostsensitive to dust deposition. Our study site off the west coast of Haiti is down stream of light-REE depleted bedrock whereas REE in African dust, transported by the easterly trade winds,reflect average crustal abundances. This unique "upstream" source signature allows forterrestrial contamination of the dust-wind signal to be ruled out. Light REE concentrations (esp.Nd and Pr) demonstrate an order of magnitude increase within coral aragonite coincident withmajor African dust plume events throughout the past decade, with Nd/Ca and Pr/Ca increasingfrom an average of 27 nmol/mol to an average 144 nmol/mol and an average of 5 nmol/mol toan average of 37 nmol/mol, respectively, during major African dust plume events. Monthly-resolved REE analysis shows these REE peaks coincide with the summer dust season rather thanHaiti's two wet seasons in spring and autumn. Regression of our coral REE dust proxy tosatellite records of

Apatite intergrowths in clinopyroxene megacrysts from the Ostrzyca Proboszczowicka (SW Poland) basanite

Science.gov (United States)

Lipa, Danuta; Puziewicz, Jacek; Ntaflos, Theodoros; Matusiak-Małek, Magdalena

2015-04-01

The Cenozoic basanite from the Ostrzyca Proboszczowicka in Lower Silesia (SW Poland) belongs to numerous lavas occurring in the NE part of the Central European Volcanic Province. Basanite contains clinopyroxene megacrysts up to 3 cm in size. The clinopyroxene has the composition of aluminian-sodian diopside (mg# 0.61-0.70, 0.08-0.12 atoms Na pfu and 0.88-0.93 atoms Ca pfu). Cr is absent. The REE contents are above the primitive mantle reaching up to 18 x PM at Nd. Primitive-mantle normalized REE patterns show enrichment in LREE relative to HREE (LaN/LuN=3.81-5.01). The REE patterns of all the megacrysts show deflection in La-Nd. The trace element patterns are characterized by positive Zr, Hf and in some cases also Ta anomalies, and negative U, La, Sr, Ti and Pb ones. In some samples strong depletion (down to 0.01 x PM) in Rb and Ba is observed.The Ostrzyca megacrysts formed cumulate, which crystallized from magma similar to the host basanite, but more fractionated and enriched in REE, particularly in LREE (Lipa et al., 2014). This happened at mid-crustal depths (10-15 km) and the new pulse of basanitic magma entrained the crystals forming the non-solidified cumulate and brought them to the surface (Lipa et al., 2014). Clinopyroxene megacrysts contain large, transparent, euhedral apatite crystals up to 7 mm. The major element composition indicates the fluor-apatite with F content ranging from 0.87 to 1.93 wt.%. Chlorine content is strongly variable between grains (0.05-1.75 wt.%). Apatite is strongly enriched in LREE relative to HREE (LaN/LuN=60.39-62.23, about 1000 x PM for LREE and about 10 x PM for HREE). The REE patterns are nearly linear, with slight positive Nd and Gd anomalies. The trace element patterns are characterized by very strong negative anomalies of HFSE (Nb, Ta, Zr, Hf, Ti) and Pb, and weaker negative Sr anomaly. Concentration of Yb and Lu is on the level 10 x PM, whereas Rb, Hf and Ti are depleted relative to PM. Apatite preceded clinopyroxene

Nutritional intake of gut failure patients on home parenteral nutrition

International Nuclear Information System (INIS)

DiCecco, S.; Nelson, J.; Burnes, J.; Fleming, C.R.

1987-01-01

Nutrient intake patterns were analyzed in 23 patients with gut failure who were receiving home parenteral nutrition (HPN). All patients had stable weights without changes in intravenous calories or protein for 3 consecutive months. Our objectives were to assess oral intake of calories, carbohydrates, fat, and protein, to examine relationships between oral nutrient intakes and disease categories, and to compare oral and intravenous intakes to calculated resting energy expenditure (REE). Two patterns of oral nutrient intake were identified among the patients. Patients with short bowel syndrome, regardless of the underlying disease, consumed calories by mouth that clearly exceeded calculated resting energy expenditure (short bowel, non-Crohn's, 170% of REE; short bowel, Crohn's, 200 of REE); however, calories approximating the REE had to be given via HPN, suggesting that efficiency of absorption was at a very low level. Patients with diffuse gut diseases (radiation enteritis or pseudo-obstruction syndromes) had very low intakes of oral nutrients. The distribution of oral calories among carbohydrate, protein, and fat did not differ among the disease categories

Rare earth elements in street dust and associated health risk in a municipal industrial base of central China.

Science.gov (United States)

Sun, Guangyi; Li, Zhonggen; Liu, Ting; Chen, Ji; Wu, Tingting; Feng, Xinbin

2017-12-01

The content levels, distribution characteristics, and health risks associated with 15 rare earth elements (REEs) in urban street dust from an industrial city, Zhuzhou, in central China were investigated. The total REE content (∑REE) ranged from 66.1 to 237.4 mg kg -1 , with an average of 115.9 mg kg -1 , which is lower than that of Chinese background soil and Yangtze river sediment. Average content of the individual REE in street dust decreased in the order Ce > La > Nd > Y > Pr > Sm > Gd > Dy > Er > Yb > Eu > Ho > Tb > Tm > Lu. The chondrite-normalized REE pattern indicated light REE (LREE) enrichment, a relatively steep LREE trend, heavy REE (HREE) depletion, a flat HREE trend, a Eu-negative anomaly and a Ce-positive anomaly. Foremost heavy local soil and to less degree anthropogenic pollution are the main sources of REE present in street dust. Health risk associated with the exposure of REE in street dust was assessed based on the carcinogenic and non-carcinogenic effect and lifetime average daily dose. The obtained cancer and non-cancer risk values prompt for no augmented health hazard. However, children had greater health risks than that of adults.

Uptake of rare earth elements by dryopteris erythrosora (autumn fern)

International Nuclear Information System (INIS)

Ozaki, Takuo; Enomoto, Shuichi

2001-01-01

Mechanisms of uptake of rare earth elements (REEs) were investigated, particularly those by REE accumulator species (autumn fern). Rare earth elements are practically insoluble under natural conditions, suggesting some unknown mechanisms in REE accumulator species. In the present investigation, two notable phenomena were observed. (1) Concerning the ionic-radius dependence of REE uptake by leaves, nonaccumulator species showed an extremely high uptake for Y compared with the adjacent-ionic-radius REEs in the multitracer, while accumulator species showed no anomaly. (2) REE uptake by autumn fern was influenced by the addition of chelating chemical reagents in the uptake solution, while no effect was observed for nonaccumulator species. (author)

Agave tequilana MADS genes show novel expression patterns in meristems, developing bulbils and floral organs.

Science.gov (United States)

Delgado Sandoval, Silvia del Carmen; Abraham Juárez, María Jazmín; Simpson, June

2012-03-01

Agave tequilana is a monocarpic perennial species that flowers after 5-8 years of vegetative growth signaling the end of the plant's life cycle. When fertilization is unsuccessful, vegetative bulbils are induced on the umbels of the inflorescence near the bracteoles from newly formed meristems. Although the regulation of inflorescence and flower development has been described in detail for monocarpic annuals and polycarpic species, little is known at the molecular level for these processes in monocarpic perennials, and few studies have been carried out on bulbils. Histological samples revealed the early induction of umbel meristems soon after the initiation of the vegetative to inflorescence transition in A. tequilana. To identify candidate genes involved in the regulation of floral induction, a search for MADS-box transcription factor ESTs was conducted using an A. tequilana transcriptome database. Seven different MIKC MADS genes classified into 6 different types were identified based on previously characterized A. thaliana and O. sativa MADS genes and sequences from non-grass monocotyledons. Quantitative real-time PCR analysis of the seven candidate MADS genes in vegetative, inflorescence, bulbil and floral tissues uncovered novel patterns of expression for some of the genes in comparison with orthologous genes characterized in other species. In situ hybridization studies using two different genes showed expression in specific tissues of vegetative meristems and floral buds. Distinct MADS gene regulatory patterns in A. tequilana may be related to the specific reproductive strategies employed by this species.

Magmatic evolution of the Jbel Boho alkaline complex in the Bou Azzer inlier (Anti-Atlas/Morocco) and its relation to REE mineralization

Science.gov (United States)

Benaouda, Rachid; Holzheid, Astrid; Schenk, Volker; Badra, Lakhlifi; Ennaciri, Aomar

2017-05-01

The Jbel Boho complex (Anti-Atlas/Morocco) is an alkaline magmatic complex that was formed during the Precambrian-Cambrian transition, contemporaneous with the lower early Cambrian dolomite sequence. The complex consists of a volcanic sequence comprising basanites, trachyandesites, trachytes and rhyolites that is intruded by a syenitic pluton. Both the volcanic suite and the pluton are cut by later microsyenitic and rhyolitic dykes. Although all Jbel Boho magmas were probably ultimately derived from the same, intraplate or plume-like source, new geochemical evidence supports the concept of a minimum three principal magma generations having formed the complex. Whereas all volcanic rocks (first generation) are LREE enriched and appear to be formed by fractional crystallization of a mantle-derived magma, resulting in strong negative Eu anomalies in the more evolved rocks associated with low Zr/Hf and Nb/Ta values, the younger syenitic pluton displays almost no negative Eu anomaly and very high Zr/Hf and Nb/Ta. The syenite is considered to be formed by a second generation of melt and likely formed through partial melting of underplated mafic rocks. The syenitic pluton consists of two types of syenitic rocks; olivine syenite and quartz syenite. The presence of quartz and a strong positive Pb anomaly in the quartz syenite contrasts strongly with the negative Pb anomaly in the olivine syenite and suggests the latter results from crustal contamination of the former. The late dyke swarm (third generation of melt) comprises microsyenitic and subalkaline rhyolitic compositions. The strong decrease of the alkali elements, Zr/Hf and Nb/Ta and the high SiO2 contents in the rhyolitic dykes might be the result of mineral fractionation and addition of mineralizing fluids, allowing inter-element fractionation of even highly incompatible HFSE due to the presence of fluorine. The occurrence of fluorite in some volcanic rocks and the Ca-REE-F carbonate mineral synchysite in the dykes

Rare earth elements in pore waters from Cabo Friós western boundary upwelling system

Science.gov (United States)

Smoak, J. M.; Silva-Filho, E. V.; Rousseau, T.; Albuquerque, A. L.; Caldeira, P. P.; Moreira, M.

2015-12-01

Rare earth elements (REE) are a group of reactive trace elements in aqueous media, they have a coherent chemical behavior with however a subtle and gradual shift in physicochemical properties allowing their use as tracers of sources and processes. Uncertainties on their oceanic inputs and outputs still remains [Arsouze et al., 2009; Siddall et al., 2008; Tachikawa et al., 2003]. The water-sediment interface were early on identified as a relevant REE source due to the high distribution coefficient between sediments and pore waters [Elderfield and Sholkovitz, 1987] and substantially higher concentration then the water column [Abbott et al., 2015; Haley et al., 2004; Sholkovitz et al., 1989; Soyol-Erdene and Huh, 2013]. Here we present a cross shelf transect of 4 short pore waters REE profiles on a 680 km2 mud bank located in the region of Cabo Frio, Brazil. This study reveals similar trends at the four sites: a REE production zone reflected by a maximum in concentration at the top of the sediment evolving with depth toward a REE consumption zone reflected by a minimum in REE concentrations. PAAS normalized patterns shows 1) a progressive depletion in LREE with depth with HREE/LREE ratios comprised between 1.1 and 1.6 in the 2 first centimeters evolving gradually to ratios comprised between 2.8 and 4.7 above 7 cm 2) A sharp gradient in negative Ce anomaly with Ce/Ce* values reaching 0.3. With maximum Nd concentrations comprised between 780 and 1200 pmol.kg and considering that seawater Nd concentrations of Brazilian shelf bottom waters are comprised between 24 and 50 pmol.Kg-1 we apply the Fick´s First Law of diffusion and estimate that 340 +/- 90 nmol. m-2 Y-1 of Nd is released in the Cabo frio´s mudbank. This flux is in the same order of magnitude of recent estimates by [Abbott et al., 2015] in the slope of Oregon´s margin. Unraveling processes responsible for the REE production zone will help to refine the global REE fluxes estimates.

DNA methylation patterns in tissues from mid-gestation bovine foetuses produced by somatic cell nuclear transfer show subtle abnormalities in nuclear reprogramming

Directory of Open Access Journals (Sweden)

Lee Rita SF

2010-03-01

Full Text Available Abstract Background Cloning of cattle by somatic cell nuclear transfer (SCNT is associated with a high incidence of pregnancy failure characterized by abnormal placental and foetal development. These abnormalities are thought to be due, in part, to incomplete re-setting of the epigenetic state of DNA in the donor somatic cell nucleus to a state that is capable of driving embryonic and foetal development to completion. Here, we tested the hypothesis that DNA methylation patterns were not appropriately established during nuclear reprogramming following SCNT. A panel of imprinted, non-imprinted genes and satellite repeat sequences was examined in tissues collected from viable and failing mid-gestation SCNT foetuses and compared with similar tissues from gestation-matched normal foetuses generated by artificial insemination (AI. Results Most of the genomic regions examined in tissues from viable and failing SCNT foetuses had DNA methylation patterns similar to those in comparable tissues from AI controls. However, statistically significant differences were found between SCNT and AI at specific CpG sites in some regions of the genome, particularly those associated with SNRPN and KCNQ1OT1, which tended to be hypomethylated in SCNT tissues. There was a high degree of variation between individuals in methylation levels at almost every CpG site in these two regions, even in AI controls. In other genomic regions, methylation levels at specific CpG sites were tightly controlled with little variation between individuals. Only one site (HAND1 showed a tissue-specific pattern of DNA methylation. Overall, DNA methylation patterns in tissues of failing foetuses were similar to apparently viable SCNT foetuses, although there were individuals showing extreme deviant patterns. Conclusion These results show that SCNT foetuses that had developed to mid-gestation had largely undergone nuclear reprogramming and that the epigenetic signature at this stage was not a

Neuromolecular Imaging Shows Temporal Synchrony Patterns between Serotonin and Movement within Neuronal Motor Circuits in the Brain

Directory of Open Access Journals (Sweden)

Patricia A. Broderick

2013-06-01

Full Text Available The present discourse links the electrical and chemical properties of the brain with neurotransmitters and movement behaviors to further elucidate strategies to diagnose and treat brain disease. Neuromolecular imaging (NMI, based on electrochemical principles, is used to detect serotonin in nerve terminals (dorsal and ventral striata and somatodendrites (ventral tegmentum of reward/motor mesocorticolimbic and nigrostriatal brain circuits. Neuronal release of serotonin is detected at the same time and in the same animal, freely moving and unrestrained, while open-field behaviors are monitored via infrared photobeams. The purpose is to emphasize the unique ability of NMI and the BRODERICK PROBE® biosensors to empirically image a pattern of temporal synchrony, previously reported, for example, in Aplysia using central pattern generators (CPGs, serotonin and cerebral peptide-2. Temporal synchrony is reviewed within the context of the literature on central pattern generators, neurotransmitters and movement disorders. Specifically, temporal synchrony data are derived from studies on psychostimulant behavior with and without cocaine while at the same time and continuously, serotonin release in motor neurons within basal ganglia, is detected. The results show that temporal synchrony between the neurotransmitter, serotonin and natural movement occurs when the brain is NOT injured via, e.g., trauma, addictive drugs or psychiatric illness. In striking contrast, in the case of serotonin and cocaine-induced psychostimulant behavior, a different form of synchrony and also asynchrony can occur. Thus, the known dysfunctional movement behavior produced by cocaine may well be related to the loss of temporal synchrony, the loss of the ability to match serotonin in brain with motor activity. The empirical study of temporal synchrony patterns in humans and animals may be more relevant to the dynamics of motor circuits and movement behaviors than are studies of

Neuromolecular Imaging Shows Temporal Synchrony Patterns between Serotonin and Movement within Neuronal Motor Circuits in the Brain.

Science.gov (United States)

Broderick, Patricia A

2013-06-21

The present discourse links the electrical and chemical properties of the brain with neurotransmitters and movement behaviors to further elucidate strategies to diagnose and treat brain disease. Neuromolecular imaging (NMI), based on electrochemical principles, is used to detect serotonin in nerve terminals (dorsal and ventral striata) and somatodendrites (ventral tegmentum) of reward/motor mesocorticolimbic and nigrostriatal brain circuits. Neuronal release of serotonin is detected at the same time and in the same animal, freely moving and unrestrained, while open-field behaviors are monitored via infrared photobeams. The purpose is to emphasize the unique ability of NMI and the BRODERICK PROBE® biosensors to empirically image a pattern of temporal synchrony, previously reported, for example, in Aplysia using central pattern generators (CPGs), serotonin and cerebral peptide-2. Temporal synchrony is reviewed within the context of the literature on central pattern generators, neurotransmitters and movement disorders. Specifically, temporal synchrony data are derived from studies on psychostimulant behavior with and without cocaine while at the same time and continuously, serotonin release in motor neurons within basal ganglia, is detected. The results show that temporal synchrony between the neurotransmitter, serotonin and natural movement occurs when the brain is NOT injured via, e.g., trauma, addictive drugs or psychiatric illness. In striking contrast, in the case of serotonin and cocaine-induced psychostimulant behavior, a different form of synchrony and also asynchrony can occur. Thus, the known dysfunctional movement behavior produced by cocaine may well be related to the loss of temporal synchrony, the loss of the ability to match serotonin in brain with motor activity. The empirical study of temporal synchrony patterns in humans and animals may be more relevant to the dynamics of motor circuits and movement behaviors than are studies of static parameters

Rare earth element distributions in the West Pacific: Trace element sources and conservative vs. non-conservative behavior

Science.gov (United States)

Behrens, Melanie K.; Pahnke, Katharina; Paffrath, Ronja; Schnetger, Bernhard; Brumsack, Hans-Jürgen

2018-03-01

Recent studies suggest that transport and water mass mixing may play a dominant role in controlling the distribution of dissolved rare earth element concentrations ([REE]) at least in parts of the North and South Atlantic and the Pacific Southern Ocean. Here we report vertically and spatially high-resolution profiles of dissolved REE concentrations ([REE]) along a NW-SE transect in the West Pacific and examine the processes affecting the [REE] distributions in this area. Surface water REE patterns reveal sources of trace element (TE) input near South Korea and in the tropical equatorial West Pacific. Positive europium anomalies and middle REE enrichments in surface and subsurface waters are indicative of TE input from volcanic islands and fingerprint in detail small-scale equatorial zonal eastward transport of TEs to the iron-limited tropical East Pacific. The low [REE] of North and South Pacific Tropical Waters and Antarctic Intermediate Water are a long-range (i.e., preformed) laterally advected signal, whereas increasing [REE] with depth within North Pacific Intermediate Water result from release from particles. Optimum multiparameter analysis of deep to bottom waters indicates a dominant control of lateral transport and mixing on [REE] at the depth of Lower Circumpolar Deep Water (≥3000 m water depth; ∼75-100% explained by water mass mixing), allowing the northward tracing of LCDW to ∼28°N in the Northwest Pacific. In contrast, scavenging in the hydrothermal plumes of the Lau Basin and Tonga-Fiji area at 1500-2000 m water depth leads to [REE] deficits (∼40-60% removal) and marked REE fractionation in the tropical West Pacific. Overall, our data provide evidence for active trace element input both near South Korea and Papua New Guinea, and for a strong lateral transport component in the distribution of dissolved REEs in large parts of the West Pacific.

Seizures and Sleep in the Thalamus: Focal Limbic Seizures Show Divergent Activity Patterns in Different Thalamic Nuclei.

Science.gov (United States)

Feng, Li; Motelow, Joshua E; Ma, Chanthia; Biche, William; McCafferty, Cian; Smith, Nicholas; Liu, Mengran; Zhan, Qiong; Jia, Ruonan; Xiao, Bo; Duque, Alvaro; Blumenfeld, Hal

2017-11-22

The thalamus plays diverse roles in cortical-subcortical brain activity patterns. Recent work suggests that focal temporal lobe seizures depress subcortical arousal systems and convert cortical activity into a pattern resembling slow-wave sleep. The potential simultaneous and paradoxical role of the thalamus in both limbic seizure propagation, and in sleep-like cortical rhythms has not been investigated. We recorded neuronal activity from the central lateral (CL), anterior (ANT), and ventral posteromedial (VPM) nuclei of the thalamus in an established female rat model of focal limbic seizures. We found that population firing of neurons in CL decreased during seizures while the cortex exhibited slow waves. In contrast, ANT showed a trend toward increased neuronal firing compatible with polyspike seizure discharges seen in the hippocampus. Meanwhile, VPM exhibited a remarkable increase in sleep spindles during focal seizures. Single-unit juxtacellular recordings from CL demonstrated reduced overall firing rates, but a switch in firing pattern from single spikes to burst firing during seizures. These findings suggest that different thalamic nuclei play very different roles in focal limbic seizures. While limbic nuclei, such as ANT, appear to participate directly in seizure propagation, arousal nuclei, such as CL, may contribute to depressed cortical function, whereas sleep spindles in relay nuclei, such as VPM, may interrupt thalamocortical information flow. These combined effects could be critical for controlling both seizure severity and impairment of consciousness. Further understanding of differential effects of seizures on different thalamocortical networks may lead to improved treatments directly targeting these modes of impaired function. SIGNIFICANCE STATEMENT Temporal lobe epilepsy has a major negative impact on quality of life. Previous work suggests that the thalamus plays a critical role in thalamocortical network modulation and subcortical arousal

Provenance and paleoweathering reconstruction of the Mesoproterozoic Hongshuizhuang Formation (1.4 Ga), northern North China

Science.gov (United States)

Luo, Qingyong; Zhong, Ningning; Wang, Yannian; Ma, Ling; Li, Min

2015-10-01

This is the first study presenting major and trace elemental data from the Mesoproterozoic Hongshuizhuang Formation shales in Yanshan basin, North China, in order to reconstruct its provenance and chemical weathering history. The shales are strongly depleted in Na2O and Sr and enriched in Y and transition metal elements relative to upper continental crust. Low Zr concentrations and various discriminant plots (e.g., Th/Sc-Zr/Sc and Al2O3-TiO2-Zr) indicate insignificant mineral sorting or recycling of these shales. The rocks show light rare earth element (REE) enrichment (La/YbCN = 3.99-6.92), flat heavy REE, and significantly negative Eu anomalies (Euan = 0.57-0.68) in chondrite-normalized REE patterns, similar to post-Archean Australian average shales. The fairly uniform REE patterns and trace element ratios indicate that the Hongshuizhuang Formation shales were derived from a felsic source area with granodiorite as the dominant contributor. Mixing calculations suggest a mixture of 30 % granite porphyry, 5 % basalt, and 65 % granodiorite as the possible source of the shales, also supporting that granodiorite was the predominant source. Intense chemical weathering of the source terrain is indicated by high values of the premetasomatized chemical index of alteration, plagioclase index of alteration, Rb/Sr, a strong positive correlation between TiO2 and Al2O3, depletion of CaO, Na2O, and Sr, and mineral compositions. Such strong chemical weathering suggests a warm and wet paleoclimate, perhaps due to high atmospheric CO2 and CH4 concentrations, and a near-equatorial location of the North China Craton in the Columbia supercontinent at 1.4 Ga.

Rare earth and trace element signatures for assessing an impact of rock mining and processing on the environment: Wiśniówka case study, south-central Poland.

Science.gov (United States)

Migaszewski, Zdzisław M; Gałuszka, Agnieszka; Dołęgowska, Sabina

2016-12-01

A detailed hydrogeochemical study was performed in the Wiśniówka mining area (south-central Poland). This covered three acid pit bodies, historic tailings acid ponds, acid pools, and additionally two neighboring rivers. All these acid mine drainage (AMD) waters are characterized by the pH in the range of 1.7 (pools) to 3.5 (tailings ponds). The most interesting is the Podwiśniówka acid pit lake that shows a very low pH (2.2-2.5) and very high concentrations of SO 4 2- (2720-5460 mg/L), Fe (545-1140 mg/L), Al (86.2 mg/L), As (9603-24,883 μg/L), Co (1317-3458 μg/L), Cr (753-2047 μg/L), Cu (6307-18,879 μg/L), Ni (1168-3127 μg/L), and rare earth element (REE) (589-1341 μg/L). In addition, seeps that drain the Podwiśniówka mine tailings and partly aggregate piles form strong acid pools in the mining area. Along with these pools, in which As and REE contents reach 369,726 and 6288 μg/L, respectively, these waters are among the most distinctive As- and REE-rich AMD surface waters across the world. It is noteworthy that the Podwiśniówka acid pit lake and Wiśniówka Duża acid pit sump exhibit different element signatures and REE concentration patterns normalized to North American Composite Shale (NASC): the Podwiśniówka acid pit lake always shows a characteristic roof-shaped medium REE (MREE) profile with distinct enrichments in Gd, Eu, and Tb whereas the other one displays a step-shaped heavy REE (HREE) profile with positive Tb and Gd anomalies. The REE undergo fractionation during weathering and the subsequent leaching of dissolved and suspended fractions from rocks to acid water bodies where these and other elements are further fractionated by geochemical processes. This study shows that the individual REE have greater affinities for Mn, HREE for Fe and SO 4 2- , and only La and Ce for Al. This specific water geochemistry has enabled us to (i) pinpoint the location of AMD "hot spots" originated from quartzite mining and processing operations

Uranium-polymetallic ore-forming system and mechanism of the black rock series in the southeast continental margin of Yangtze plate

International Nuclear Information System (INIS)

Qi Fucheng; Zhang Zilong; He Zhongbo; Li Zhixing; Wang Wenquan; Su Xiangli; Zhang Chao

2011-01-01

It is the indisputable fact that the large scale uranium-polymetallic mineralization had happen in the southeast continental margin of Yangtze plate. The rations of Fe/Ti, (Fe+Mn)/Ti, Al/(Al+Fe+Mn), and Ni-Co-Zn diagrams show that the siliceous rocks and phosphorites are the products of hydrothermal sedimentation in these area. In La/Yb-REE diagrams the data of phosphorites are clustered in the area of basales. Obviously, the source of phophorite's ore-forming materials is closely related with the geological processes at depth. REE patterns are characterized by a low content in total and a gradually increasing with the increasing of REE atomic number, and the NASC-normalized value ranging between the upper and the lower limits of typical hydrothermal deposits. The large scale uranium-polymetallic mineralization was controlled by the environment of continental margin rifting. The authors propose that thermal sedimentation or exhalation-sedimentation is the mechanism of the large scale uranium-polymetallic mineralization in the southeast continental margin of the Yangtze plate. (authors)

Green glass vitrophyre 78526 - An impact of very low-Ti mare basalt composition

Science.gov (United States)

Warner, R. D.; Taylor, G. J.; Kiel, K.; Planner, H. H.; Nehru, C. E.; Ma, M.-S.; Schmitt, R. A.

1978-01-01

Rake sample 78526 is an 8.77 g rock consisting primarily of vitrophyric pale green glass with subordinate mineral and lithic relics. Petrographic and compositional evidence leads to the following conclusions: (1) the bulk composition represents that of a mixture formed by impact melting of at least two different textural and compositional varieties of VLT mare basalt that are now present in the rock as lithic relics and a poorly defined low-Ti mare basalt component observed in thin section only in the form of isolated mineral relics; (2) the admixed VLT mare basalts had REE abundances lower than those found in other mare basalts (but probably higher than emerald green glass) and REE patterns showing significant enrichment of the heavy relative to light REE's, suggesting that they were derived by comparatively high degrees of partial melting of a clinopyroxene-rich source region; and (3) the impact melt supercooled to produce the vitrophyre, with rather sharply contrasting textural domains present in the vitrophyre resulting from differences in nucleation kinetics and degrees of supercooling in various portions of the sample.

Rare earth elements in human and animal health: State of art and research priorities

Energy Technology Data Exchange (ETDEWEB)

Pagano, Giovanni, E-mail: gbpagano@tin.it [University of Naples “Federico II”, Environmental Hygiene, via Cinthia, I-80126 Naples (Italy); Aliberti, Francesco; Guida, Marco [University of Naples “Federico II”, Environmental Hygiene, via Cinthia, I-80126 Naples (Italy); Oral, Rahime [Ege University, Faculty of Fisheries, TR-35100 Bornova, İzmir (Turkey); Siciliano, Antonietta [University of Naples “Federico II”, Environmental Hygiene, via Cinthia, I-80126 Naples (Italy); Trifuoggi, Marco [University of Naples “Federico II”, Department of Chemical Sciences, I-80126 Naples (Italy); Tommasi, Franca [“Aldo Moro” Bari University, Department of Biology, I-70126 Bari (Italy)

2015-10-15

Background: A number of applications have been developed using rare earth elements (REE), implying several human exposures and raising unsolved questions as to REE-associated health effects. Methods: A MedLine survey was retrieved from early reports (1980s) up to June 2015, focused on human and animal exposures to REE. Literature from animal models was selected focusing on REE-associated health effects. Results: Some REE occupational exposures, in jobs such as glass polishers, photoengravers and movie projectionists showed a few case reports on health effects affecting the respiratory system. No case-control or cohort studies of occupational REE exposures were retrieved. Environmental exposures have been biomonitored in populations residing in REE mining areas, showing REE accumulation. The case for a iatrogenic REE exposure was raised by the use of gadolinium-based contrast agents for nuclear magnetic resonance. Animal toxicity studies have shown REE toxicity, affecting a number of endpoints in liver, lungs and blood. On the other hand, the use of REE as feed additives in livestock is referred as a safe and promising device in zootechnical activities, possibly suggesting a hormetic effect both known for REE and for other xenobiotics. Thus, investigations on long-term exposures and observations are warranted. Conclusion: The state of art provides a limited definition of the health effects in occupationally or environmentally REE-exposed human populations. Research priorities should be addressed to case-control or cohort studies of REE-exposed humans and to life-long animal experiments. - Highlights: • An extensive number of activities have been developed utilizing rare earth elements (REE). • The literature of REE-associated health effects in humans, and on animal studies is reviewed. • The main literature gaps are discussed, in epidemiological and in animal studies. • Prospects studies are suggested, aimed at evaluating long-term effects of REE exposures

Rare earth elements in human and animal health: State of art and research priorities

International Nuclear Information System (INIS)

Pagano, Giovanni; Aliberti, Francesco; Guida, Marco; Oral, Rahime; Siciliano, Antonietta; Trifuoggi, Marco; Tommasi, Franca

2015-01-01

Background: A number of applications have been developed using rare earth elements (REE), implying several human exposures and raising unsolved questions as to REE-associated health effects. Methods: A MedLine survey was retrieved from early reports (1980s) up to June 2015, focused on human and animal exposures to REE. Literature from animal models was selected focusing on REE-associated health effects. Results: Some REE occupational exposures, in jobs such as glass polishers, photoengravers and movie projectionists showed a few case reports on health effects affecting the respiratory system. No case-control or cohort studies of occupational REE exposures were retrieved. Environmental exposures have been biomonitored in populations residing in REE mining areas, showing REE accumulation. The case for a iatrogenic REE exposure was raised by the use of gadolinium-based contrast agents for nuclear magnetic resonance. Animal toxicity studies have shown REE toxicity, affecting a number of endpoints in liver, lungs and blood. On the other hand, the use of REE as feed additives in livestock is referred as a safe and promising device in zootechnical activities, possibly suggesting a hormetic effect both known for REE and for other xenobiotics. Thus, investigations on long-term exposures and observations are warranted. Conclusion: The state of art provides a limited definition of the health effects in occupationally or environmentally REE-exposed human populations. Research priorities should be addressed to case-control or cohort studies of REE-exposed humans and to life-long animal experiments. - Highlights: • An extensive number of activities have been developed utilizing rare earth elements (REE). • The literature of REE-associated health effects in humans, and on animal studies is reviewed. • The main literature gaps are discussed, in epidemiological and in animal studies. • Prospects studies are suggested, aimed at evaluating long-term effects of REE exposures

Rare Earth Element Partitioning in Lunar Minerals: An Experimental Study

Science.gov (United States)

McIntosh, E. C.; Rapp, J. F.; Draper, D. S.

2016-01-01

The partitioning behavior of rare earth elements (REE) between minerals and melts is widely used to interpret the petrogenesis and geologic context of terrestrial and extra-terrestrial samples. REE are important tools for modelling the evolution of the lunar interior. The ubiquitous negative Eu anomaly in lunar basalts is one of the main lines of evidence to support the lunar magma ocean (LMO) hypothesis, by which the plagioclase-rich lunar highlands were formed as a flotation crust during differentiation of a global-scale magma ocean. The separation of plagioclase from the mafic cumulates is thought to be the source of the Eu depletion, as Eu is very compatible in plagioclase. Lunar basalts and volcanic glasses are commonly depleted in light REEs (LREE), and more enriched in heavy REEs (HREE). However, there is very little experimental data available on REE partitioning between lunar minerals and melts. In order to interpret the source of these distinctive REE patterns, and to model lunar petrogenetic processes, REE partition coefficients (D) between lunar minerals and melts are needed at conditions relevant to lunar processes. New data on D(sub REE) for plagioclase, and pyroxenes are now available, but there is limited available data for olivine/melt D(sub REE), particularly at pressures higher than 1 bar, and in Fe-rich and reduced compositions - all conditions relevant to the lunar mantle. Based on terrestrial data, REE are highly incompatible in olivine (i.e. D much less than 1), however olivine is the predominant mineral in the lunar interior, so it is important to understand whether it is capable of storing even small amounts of REE, and how the REEs might be fractionatied, in order to understand the trace element budget of the lunar interior. This abstract presents results from high-pressure and temperature experiments investigating REE partitioning between olivine and melt in a composition relevant to lunar magmatism.

Distribution of rare earth elements in an alluvial aquifer affected by acid mine drainage: the Guadiamar aquifer (SW Spain)

International Nuclear Information System (INIS)

Olias, M.; Ceron, J.C.; Fernandez, I.; Rosa, J. de la

2005-01-01

This work analyses the spatial distribution, the origin, and the shale-normalised fractionation patterns of the rare earth elements (REE) in the alluvial aquifer of the Guadiamar River (south-western Spain). This river received notoriety in April 1998 for a spill that spread a great amount of slurry (mainly pyrites) and acid waters in a narrow strip along the river course. Groundwaters and surface waters were sampled to analyse, among other elements, the REEs. Their spatial distribution shows a peak close to the mining region, in an area with low values of pH and high concentrations of sulphates and other metals such as Zn, Cu, Co, Ni, Pb, and Cd. The patterns of shale-normalised fractionation at the most-contaminated points show an enrichment in the middle rare earth elements (MREE) with respect to the light (LREE) and heavy (HREE) ones, typical of acid waters. The Ce-anomaly becomes more negative as pH increases, due to the preferential fractionation of Ce in oxyhydroxides of Fe. - Pollution of the aquifer with rare earth elements is documented at a site of a major spill from a mining operation

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

Science.gov (United States)

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

2015-08-18

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

Are predictive equations for estimating resting energy expenditure accurate in Asian Indian male weightlifters?

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Mini Joseph

2017-01-01

Full Text Available Background: The accuracy of existing predictive equations to determine the resting energy expenditure (REE of professional weightlifters remains scarcely studied. Our study aimed at assessing the REE of male Asian Indian weightlifters with indirect calorimetry and to compare the measured REE (mREE with published equations. A new equation using potential anthropometric variables to predict REE was also evaluated. Materials and Methods: REE was measured on 30 male professional weightlifters aged between 17 and 28 years using indirect calorimetry and compared with the eight formulas predicted by Harris–Benedicts, Mifflin-St. Jeor, FAO/WHO/UNU, ICMR, Cunninghams, Owen, Katch-McArdle, and Nelson. Pearson correlation coefficient, intraclass correlation coefficient, and multiple linear regression analysis were carried out to study the agreement between the different methods, association with anthropometric variables, and to formulate a new prediction equation for this population. Results: Pearson correlation coefficients between mREE and the anthropometric variables showed positive significance with suprailiac skinfold thickness, lean body mass (LBM, waist circumference, hip circumference, bone mineral mass, and body mass. All eight predictive equations underestimated the REE of the weightlifters when compared with the mREE. The highest mean difference was 636 kcal/day (Owen, 1986 and the lowest difference was 375 kcal/day (Cunninghams, 1980. Multiple linear regression done stepwise showed that LBM was the only significant determinant of REE in this group of sportspersons. A new equation using LBM as the independent variable for calculating REE was computed. REE for weightlifters = −164.065 + 0.039 (LBM (confidence interval −1122.984, 794.854]. This new equation reduced the mean difference with mREE by 2.36 + 369.15 kcal/day (standard error = 67.40. Conclusion: The significant finding of this study was that all the prediction equations

TKA patients with unsatisfying knee function show changes in neuromotor synergy pattern but not joint biomechanics.

Science.gov (United States)

Ardestani, Marzieh M; Malloy, Philip; Nam, Denis; Rosenberg, Aaron G; Wimmer, Markus A

2017-12-01

Nearly 20% of patients who have undergone total knee arthroplasty (TKA) report persistent poor knee function. This study explores the idea that, despite similar knee joint biomechanics, the neuro-motor synergies may be different between high-functional and low-functional TKA patients. We hypothesized that (1) high-functional TKA recruit a more complex neuro-motor synergy pattern compared to low-functional TKA and (2) high-functional TKA patients demonstrate more stride-to-stride variability (flexibility) in their synergies. Gait and electromyography (EMG) data were collected during level walking for three groups of participants: (i) high-functional TKA patients (n=13); (ii) low-functional TKA patients (n=13) and (iii) non-operative controls (n=18). Synergies were extracted from EMG data using non-negative matrix factorization. Analysis of variance and Spearman correlation analyses were used to investigate between-group differences in gait and neuro-motor synergies. Results showed that synergy patterns were different among the three groups. Control subjects used 5-6 independent neural commands to execute a gait cycle. High functional TKA patients used 4-5 independent neural commands while low-functional TKA patients relied on only 2-3 independent neural commands to execute a gait cycle. Furthermore, stride-to-stride variability of muscles' response to the neural commands was reduced up to 15% in low-functional TKAs compared to the other two groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rare earth elements, U and Th in tunnel dusts of SÃO Paulo City, Brazil

Energy Technology Data Exchange (ETDEWEB)

Nory, Renata M.; Figueireido, Ana Maria G., E-mail: renata.nory@ipen.br, E-mail: anamaria@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

2017-07-01

São Paulo is one of the most populated cities in the world, with about 20 million inhabitants in its metropolitan area, more than 12 million motor vehicles and intense industrial activity. Given its importance as a major urban center in South America and the lack of information concerning urban dust composition, the present study aimed to determine rare earth elements (REEs), U and Th mass fractions in tunnel dust, collected in the Jânio Quadros Tunnel, and to assess their possible sources. The study of REEs distribution in urban environments has become of interest over the last decades, due to the increasing industrial use of these elements. The REEs, that are as common as the most familiar metals, are found in metallurgical additives, fluid cracking catalysts and automobile converter catalysts, among other applications. In this study, which employed Instrumental Neutron Activation Analysis (INAA) as analytical technique, the mass fractions of eight REEs were determined and normalized to the chondrite concentration values. The results showed that major concentrations were found for light REEs, following the sequence Ce > La > Nd > Sm > Yb > Eu > Tb > Lu. The pattern of the results pointed to a natural origin for these elements. Regarding U and Th concentrations, the results varied between 1.0 - 9.4 μg g{sup -1} and 3.3 - 35.9 μg g{sup -1}, respectively. Since there is almost no information about the concentration of these elements in this kind of matrix in São Paulo city, these data are important to support further investigations. (author)

Non-Eosinophilic Nasal Polyps Shows Increased Epithelial Proliferation and Localized Disease Pattern in the Early Stage.

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Dong-Kyu Kim

Full Text Available Non-eosinophilic nasal polyps (NPs show less inflammatory changes and are less commonly associated with lower airway inflammatory disorders such as asthma, compared with eosinophilic NPs. However, the development of non-eosinophilic NPs which is a predominant subtype in Asian population still remains unclear.A total of 81 patients (45 with non-eosinophilic NPs and 36 with eosinophilic NPs were enrolled. Clinical information and computed tomography (CT, endoscopic, and histological findings were investigated. Tissue samples were analyzed for total IgE levels and for mRNA expression levels of interleukin (IL-4, IL-5, IL-13, interferon (IFN-γ, tumor necrosis factor (TNF-α, IL-17A, IL-22, IL-23p19, transforming growth factor (TGF-β1, TGF-β2, TGF-β3, and periostin. Immunostaining assessment of Ki-67 as a proliferation marker was performed.We found that epithelial in-growing patterns such as pseudocysts were more frequently observed in histological and endoscopic evaluations of non-eosinophilic NPs, which was linked to increase epithelial staining of Ki-67, a proliferating marker. Eosinophilic NPs were characterized by high infiltration of inflammatory cells, compared with non-eosinophilic NPs. To investigate the developmental course of each subtype, CT was analyzed according to CT scores and subtypes. Non-eosinophilic NPs showed more localized pattern and maxillary sinus involvement, but lesser olfactory involvement in early stage whereas eosinophilic NPs were characterized by diffuse ethmoidal and olfactory involvement. In addition, high ethmoidal/maxillary (E/M CT scores, indicating ethmoidal dominant involvement, were one of surrogate markers for eosinophilic NP. E/M CT scores was positively correlated with levels of TH2 inflammatory markers, including IL-4, IL-5, periostin mRNA expression and total IgE levels in NPs, whereas levels of the TH1 cytokine, IFN- γ were inversely correlated. Moreover, if the combinatorial algorithm meet the three

The study of geochemical behavior of rare earth elements in apatites from the Hormoz Island, Persian Gulf

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Ali Rostami

2014-04-01

Full Text Available The study area is located about 3 km southwest of the Hormoz Island in the Hormozgan province, in the Persian Gulf. The main rock units in the region consist of a highly altered acidic pluton cratophyre, which is responsible for apatite formation, diabasic dike, marl and altered basalt. Apatite is the only phosphate mineral in the Hormoz Island, which has accumulated REE in its crystal structure. The amount of Na2O and SiO2 oxides in apatite are high and the average content of the main elements Fe, Mg, Al, Ca are 7.5 ppm, 365 ppm, 2880 ppm and 27.8%, respectively. The Y, Mn, Rb contents increase and Sr decreases with increasing magmatic differentiation. It shows that a moderate magmatic differentiation occurred during the crystallization of apatite. The total REE content in the Hormoz apatite is high (1.22-2.25%. LREE/HREE ratio is also high. This means that Hormoz apatites are enriched in light rare earth elements. The REE normalized pattern shows a negative slope with a negative Eu anomaly. According to various diagrams based on apatite composition, it is deduced that the Hormoz apatites belong to mafic I-type granitoids with high oxidation state (Fe2O3/FeO>1.

Akinetic-rigid and tremor-dominant Parkinson's disease patients show different patterns of intrinsic brain activity.

Science.gov (United States)

Zhang, Jiuquan; Wei, Luqing; Hu, Xiaofei; Xie, Bing; Zhang, Yanling; Wu, Guo-Rong; Wang, Jian

2015-01-01

Parkinson's disease (PD) is a surprisingly heterogeneous neurodegenerative disorder. It is well established that different subtypes of PD present with different clinical courses and prognoses. However, the neural mechanism underlying these disparate presentations is uncertain. Here we used resting-state fMRI (rs-fMRI) and the regional homogeneity (ReHo) method to determine neural activity patterns in the two main clinical subgroups of PD (akinetic-rigid and tremor-dominant). Compared with healthy controls, akinetic-rigid (AR) subjects had increased ReHo mainly in right amygdala, left putamen, bilateral angular gyrus, bilateral medial prefrontal cortex (MPFC), and decreased ReHo in left post cingulate gyrus/precuneus (PCC/PCu) and bilateral thalamus. In contrast, tremor-dominant (TD) patients showed higher ReHo mostly in bilateral angular gyrus, left PCC, cerebellum_crus1, and cerebellum_6, while ReHo was decreased in right putamen, primary sensory cortex (S1), vermis_3, and cerebellum_4_5. These results indicate that AR and TD subgroups both represent altered spontaneous neural activity in default-mode regions and striatum, and AR subjects exhibit more changed neural activity in the mesolimbic cortex (amygdala) but TD in the cerebellar regions. Of note, direct comparison of the two subgroups revealed a distinct ReHo pattern primarily located in the striatal-thalamo-cortical (STC) and cerebello-thalamo-cortical (CTC) loops. Overall, our findings highlight the involvement of default mode network (DMN) and STC circuit both in AR and TD subtypes, but also underscore the importance of integrating mesolimbic-striatal and CTC loops in understanding neural systems of akinesia and rigidity, as well as resting tremor in PD. This study provides improved understanding of the pathophysiological models of different subtypes of PD. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rare earth elements in minerals of the ALHA77005 shergottite and implications for its parent magma and crystallization history

Science.gov (United States)

Lundberg, Laura L.; Crozaz, Ghislaine; Mcsween, Harry Y., Jr.

1990-01-01

Analyses of mineral REE and selected minor and trace elements were carried out on individual grains of pyroxenes, whitlockite, maskelynite, and olivine of the Antarctic shergottite ALHA77005, and the results are used to interpret its parent magma and crystallization history. The results of mineral compositions and textural observations suggest that ALHA77005 is a cumulate with about half cumulus material (olivine + chromite) and half postcumulus phases. Most of the REEs in ALHA77005 reside in whitlockite whose modal concentration is about 1 percent. Mineral REE data support previous suggestions that plagioclase and whitlockite crystallized late, and that low-Ca pyroxene initiated crystallization before high-Ca pyroxene. The REE patterns for the intercumulus liquid, calculated from distribution coefficients for ALHA77005 pyroxene, plagioclase, and whitlockite, are in very good agreement and are similar to that of Shergotty.

Beverage consumption patterns among 4-19 y old children in 2009-14 NHANES show that the milk and 100% juice pattern is associated with better diets.

Science.gov (United States)

Maillot, Matthieu; Rehm, Colin D; Vieux, Florent; Rose, Chelsea M; Drewnowski, Adam

2018-05-24

Patterns of beverage consumption among children and adolescents can be indicative of food choices and total diet quality. Analyses of beverage consumption patterns among 8119 children aged 4-19 y were based on the first 24-h recall of the National Health and Nutrition Examination Survey (2009-14 NHANES). Four pre-defined beverage patterns were: 1) milk pattern; 2) 100% juice pattern; 3) milk and 100% juice pattern; and 4) other caloric beverages. Food- and nutrient-based diet quality measures included the Healthy Eating Index 2010. Most children drank other caloric beverages, as opposed to milk (17.8%), 100% juice (5.6%), or milk and 100% juice (13.5%). Drinkers of milk and 100% juice had diets that did not differ from each other in total calories, total and added sugars, fiber, or vitamin E. Milk drinkers consumed more dairy and had higher intakes of calcium, potassium, vitamin A and vitamin D as compared to all other patterns. Juice drinkers consumed more total fruit, same amounts of whole fruit, and had higher intakes of vitamin C as compared to the other consumption patterns. Drinkers of both milk and 100% juice had the highest HEI 2010 scores of all the consumption patterns. Beverage consumption patterns built around milk and/or 100% juice were relatively uncommon. Promoting the drinking of milk and 100% juice, in preference to other caloric beverages, may be an effective strategy to improve children's diet quality. Restricting milk and 100% juice consumption may encourage the selection of other caloric beverages.

Bark and Ambrosia Beetles Show Different Invasion Patterns in the USA.

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Davide Rassati

Full Text Available Non-native bark and ambrosia beetles represent a threat to forests worldwide. Their invasion patterns are, however, still unclear. Here we investigated first, if the spread of non-native bark and ambrosia beetles is a gradual or a discontinuous process; second, which are the main correlates of their community structure; third, whether those correlates correspond to those of native species. We used data on species distribution of non-native and native scolytines in the continental 48 USA states. These data were analyzed through a beta-diversity index, partitioned into species richness differences and species replacement, using Mantel correlograms and non-metric multidimensional scaling (NMDS ordination for identifying spatial patterns, and regression on distance matrices to test the association of climate (temperature, rainfall, forest (cover area, composition, geographical (distance, and human-related (import variables with β-diversity components. For both non-native bark and ambrosia beetles, β-diversity was mainly composed of species richness difference than species replacement. For non-native bark beetles, a discontinuous invasion process composed of long distance jumps or multiple introduction events was apparent. Species richness differences were primarily correlated with differences in import values while temperature was the main correlate of species replacement. For non-native ambrosia beetles, a more continuous invasion process was apparent, with the pool of non-native species arriving in the coastal areas that tended to be filtered as they spread to interior portions of the continental USA. Species richness differences were mainly correlated with differences in rainfall among states, while rainfall and temperature were the main correlates of species replacement. Our study suggests that the different ecology of bark and ambrosia beetles influences their invasion process in new environments. The lower dependency that bark beetles have

Creació automàtica de diccionaris multilingües especialitzats en noves àrees temàtiques

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Joaquim Moré

2009-06-01

Full Text Available En aquest article presentem una eina que genera automàticament diccionaris d'equivalències multilingües especialitzats en noves àrees temàtiques. L'eina explota recursos presents a la xarxa per a cercar les equivalències i verificar-ne la idoneïtat. Aquests recursos són, d'una banda, les viquipèdies, que es poden baixar i processar de manera lliure, i, de l'altra, els materials que institucions terminològiques de referència deixen disponibles. Aquesta eina pot ser útil per als docents que elaboren materials didàctics i per als investigadors que preparen tesis, articles o manuals de referència. També pot ser útil per als traductors i per als terminòlegs que s'ocupen de la normalització terminològica d'una nova àrea temàtica en una llengua determinada, els quals estan interessats a conèixer els conceptes que encara no tenen una denominació normalitzada.

Peanut sensitization pattern in Norwegian children and adults with specific IgE to peanut show age related differences.

Science.gov (United States)

Namork, Ellen; Stensby, Berit A

2015-01-01

Peanuts contain potent food allergens and the prevalence of allergy is reported to increase, especially in children. Since peanut sensitization may differ between different geographical regions, we wanted to investigate the sensitization pattern to the individual peanut allergens in a Norwegian population. Cases reported to the Norwegian Food Allergy Register with sera positive to peanut extract were analyzed for specific IgE (sIgE) to the recombinant peanut allergens Ara h 1, Ara h 2, Ara h 3, Ara h 8 and Ara h 9 and to birch pollen extract. Serum samples negative to the above allergens were analyzed for sIgE to Ara h 6, and sIgE to Pru p 3 in peach were analyzed in sera positive to the cross-reactive allergen Ara h 9. Highest frequency of sIgE to Ara h 2, often co-sensitized to Ara h 1 and 3, were found in the small children up to 6 years of age. From the age of 6 years, sensitization to Ara h 8 was predominant. The sIgE levels to the storage proteins Ara h 1, 2 and 3 were strongly correlated, as was the sIgE levels to Ara h 8 and birch pollen extract. A low sensitization rate of sIgE to Ara h 9 in young adults was observed, which sIgE levels were very strongly correlated to Pru p 3. The sensitization to peanut allergens in a Norwegian population shows a clear age dependent pattern. The results add to the previously published research on the sensitization patterns of peanut sensitized patients in different geographical areas.

Elucidating the formation of terra fuscas using Sr–Nd–Pb isotopes and rare earth elements

International Nuclear Information System (INIS)

Hissler, Christophe; Stille, Peter; Juilleret, Jérôme; Iffly, Jean François; Perrone, Thierry; Morvan, Gilles

2015-01-01

Highlights: • Geochemical evidences on stabile phase confirm Bajocian marl as terra fusca parent material. • Precipitation/Dissolution of secondary carbonates controls geochemistry of labile phases. • This terra fusca sequence record at least four geological and environmental events. - Abstract: Carbonate weathering mantles, like terra fusca, are common in Europe but their formation and evolution is still badly understood. We propose to combine geological, mineralogical and pedological knowledge with trace element and isotope data of a weathering mantle as a novel approach to understand the evolution of terra fuscas. Sr–Nd–Pb isotopes and rare earth element (REE) contents were analyzed in a cambisol developing on a typical terra fusca on top of a condensed Bajocian limestone-marl succession from the eastern side of the Paris Basin. The isotope data, REE distribution patterns and mass balance calculations suggest that the cambisol mirrors the trace element enrichments present in this carbonate lithology, which are exceptionally high compared to global average carbonate. The deeper soil horizons are strongly enriched not only in REE (ΣREE: 2640 ppm) but also in redox-sensitive elements such as Fe (44 wt.%), V (1000 ppm), Cr (700 ppm), Zn (550 ppm), As (260 ppm), Co (45 ppm) and Cd (2.4 ppm). The trace element distribution patterns of the carbonate bedrock are similar to those of the soil suggesting their close genetic relationships. Sr–Nd–Pb isotope data allow to identify four principal components in the soil: a silicate-rich pool close to the surface, a leachable REE enriched pool at the bottom of the soil profile, the limestone on which the weathering profile developed and an anthropogenic, atmosphere-derived component detected in the soil leachates of the uppermost soil horizon. The leachable phases are mainly secondary carbonate-bearing REE phases such as bastnaesite ((X) Ca(CO 3 ) 2 F) (for X: Ce, La and Nd). The isotope data and trace element

Arabidopsis roots and shoots show distinct temporal adaptation patterns toward nitrogen starvation.

Science.gov (United States)

Krapp, Anne; Berthomé, Richard; Orsel, Mathilde; Mercey-Boutet, Stéphanie; Yu, Agnes; Castaings, Loren; Elftieh, Samira; Major, Hilary; Renou, Jean-Pierre; Daniel-Vedele, Françoise

2011-11-01

Nitrogen (N) is an essential macronutrient for plants. N levels in soil vary widely, and plants have developed strategies to cope with N deficiency. However, the regulation of these adaptive responses and the coordinating signals that underlie them are still poorly understood. The aim of this study was to characterize N starvation in adult Arabidopsis (Arabidopsis thaliana) plants in a spatiotemporal manner by an integrative, multilevel global approach analyzing growth, metabolites, enzyme activities, and transcript levels. We determined that the remobilization of N and carbon compounds to the growing roots occurred long before the internal N stores became depleted. A global metabolite analysis by gas chromatography-mass spectrometry revealed organ-specific differences in the metabolic adaptation to complete N starvation, for example, for several tricarboxylic acid cycle intermediates, but also for carbohydrates, secondary products, and phosphate. The activities of central N metabolism enzymes and the capacity for nitrate uptake adapted to N starvation by favoring N remobilization and by increasing the high-affinity nitrate uptake capacity after long-term starvation. Changes in the transcriptome confirmed earlier studies and added a new dimension by revealing specific spatiotemporal patterns and several unknown N starvation-regulated genes, including new predicted small RNA genes. No global correlation between metabolites, enzyme activities, and transcripts was evident. However, this multilevel spatiotemporal global study revealed numerous new patterns of adaptation mechanisms to N starvation. In the context of a sustainable agriculture, this work will give new insight for the production of crops with increased N use efficiency.

Determination of REEs in agricultural soils of Pernambuco by the Neutron Activation Technique

Energy Technology Data Exchange (ETDEWEB)

França, Fernanda Cláudia S.S.; Ticianelli, Regina Beck; Moreira, Edson Gonçalves; Genezini, Frederico Antonio; Albuquerque, Adriana Muniz de Almeida; Silveira, Patrícia Brandão da; Barbosa, Jonnas Thiago de Lima; Almeida, Amanda Correia de; Honorato, Eliane Valentim; Hazin, Clovis Abrahão, E-mail: nanda_lq@hotmail.com, E-mail: valentim@cnen.gov.br, E-mail: emoreira@ipen.br [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil); Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Centro Regional de Ciências Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

2017-11-01

The indiscriminate use of phosphate fertilizers causes adverse effects on biota, mainly due to the contaminants present in the rocks used in their manufacture. Among these contaminants, stand out the Rare Earth Elements (REEs) because of the significant increase in the use in several technological areas, such as in vehicle catalysts and also in fertilizer enrichment. In order to evaluate the levels of La, Sm, Nd, Yb and Lu by the Instrumental Neutron Activation Analysis (INAA), the present study aims to survey the ETRs in agricultural soils in Pernambuco/Brazil. For this study, 120 soil samples with a depth of 20 cm were collected in the main vegetable producing regions of the Metropolitan Region of Recife (RMR), evaluating organic and conventional crops with and without influenced by automotive vehicles. The results obtained when compared to the Netherlands reference values defined by the National Institute of Health and Environment (RIVM). The results were higher in all points for La (35 mg.kg-¹ at 85 mg.kg-¹) Yb, (4 mg.kg-¹ at 11 mg.kg-¹) and Lu (0.3 mg.kg-¹ at 0.7 mg.kg-¹ at 4 mg.kg-¹). For Nd (9 mg.kg-¹ at 137 mg.kg-¹) the concentrations were above the values reported by RIVM in 4 points. Comparing the types of crops evaluated with the literature, the results are found was above for all elements analyzed. It may be related to the increase in the use of phosphate fertilizers. However, in environments using smaller amounts of additives, the results were also significant and the more detailed studies are needed to evaluate other possible contamination pathways. (author)

Determination of REEs in agricultural soils of Pernambuco by the Neutron Activation Technique

International Nuclear Information System (INIS)

França, Fernanda Cláudia S.S.; Ticianelli, Regina Beck; Moreira, Edson Gonçalves; Genezini, Frederico Antonio; Albuquerque, Adriana Muniz de Almeida; Silveira, Patrícia Brandão da; Barbosa, Jonnas Thiago de Lima; Almeida, Amanda Correia de; Honorato, Eliane Valentim; Hazin, Clovis Abrahão

2017-01-01

The indiscriminate use of phosphate fertilizers causes adverse effects on biota, mainly due to the contaminants present in the rocks used in their manufacture. Among these contaminants, stand out the Rare Earth Elements (REEs) because of the significant increase in the use in several technological areas, such as in vehicle catalysts and also in fertilizer enrichment. In order to evaluate the levels of La, Sm, Nd, Yb and Lu by the Instrumental Neutron Activation Analysis (INAA), the present study aims to survey the ETRs in agricultural soils in Pernambuco/Brazil. For this study, 120 soil samples with a depth of 20 cm were collected in the main vegetable producing regions of the Metropolitan Region of Recife (RMR), evaluating organic and conventional crops with and without influenced by automotive vehicles. The results obtained when compared to the Netherlands reference values defined by the National Institute of Health and Environment (RIVM). The results were higher in all points for La (35 mg.kg-¹ at 85 mg.kg-¹) Yb, (4 mg.kg-¹ at 11 mg.kg-¹) and Lu (0.3 mg.kg-¹ at 0.7 mg.kg-¹ at 4 mg.kg-¹). For Nd (9 mg.kg-¹ at 137 mg.kg-¹) the concentrations were above the values reported by RIVM in 4 points. Comparing the types of crops evaluated with the literature, the results are found was above for all elements analyzed. It may be related to the increase in the use of phosphate fertilizers. However, in environments using smaller amounts of additives, the results were also significant and the more detailed studies are needed to evaluate other possible contamination pathways. (author)

Geological and geochemical implications of the genesis of the Qolqoleh orogenic gold mineralisation, Kurdistan Province (Iran

Directory of Open Access Journals (Sweden)

Taghipour Batoul

2015-03-01

Full Text Available The Qolqoleh gold deposit is located in the northwestern part of the Sanandaj-Sirjan Zone (SSZ, within the NE-SW trending Qolqoleh shear zone. Oligocene granitoids, Cretaceous meta-limestones, schists and metavolcanics are the main lithological units. Chondrite-normalised REE patterns of the ore-hosting metavolcanics indicate REE enrichment relative to hanging wall (chlorite-sericite schist and footwall (meta-limestone rocks. The pattern also reflects an enrichment in LREE relative to HREE. It seems that the LREE enrichment is related to the circulation of SO42- and CO2-bearing fluids and regional metamorphism in the Qolqoleh shear zone. Both positive and negative Eu anomalies are observed in shear-zone metavolcanics. These anomalies are related to the degree of plagioclase alteration during gold mineralisation and hydrothermal alteration. In progressing from a metavolcanic protomylonite to an ultramylonite, significant changes occurred in the major/trace element and REE concentration. Utilising an Al-Fe-Ti isocon for the ore-hosting metavolcanics shows that Sc, Y, K, U, P, and M-HREE (except Eu are relatively unchanged; S, As, Ag, Au, Ca, LOI, Rb and LREE are enriched, and Sr, Ba, Eu, Cr, Co and Ni decrease with an increasing degree of deformation. Based on geochemical features and comparison with other well-known shear zones in the world, the study area is best classified as an Isovolume-Gain (IVG type shear zone and orogenic type gold mineralisation.

Biosorption of metal and salt tolerant microbial isolates from a former uranium mining area. Their impact on changes in rare earth element patterns in acid mine drainage.

Science.gov (United States)

Haferburg, Götz; Merten, Dirk; Büchel, Georg; Kothe, Erika

2007-12-01

The concentration of metals in microbial habitats influenced by mining operations can reach enormous values. Worldwide, much emphasis is placed on the research of resistance and biosorptive capacities of microorganisms suitable for bioremediation purposes. Using a collection of isolates from a former uranium mining area in Eastern Thuringia, Germany, this study presents three Gram-positive bacterial strains with distinct metal tolerances. These strains were identified as members of the genera Bacillus, Micrococcus and Streptomyces. Acid mine drainage (AMD) originating from the same mining area is characterized by high metal concentrations of a broad range of elements and a very low pH. AMD was analyzed and used as incubation solution. The sorption of rare earth elements (REE), aluminum, cobalt, copper, manganese, nickel, strontium, and uranium through selected strains was studied during a time course of four weeks. Biosorption was investigated after one hour, one week and four weeks by analyzing the concentrations of metals in supernatant and biomass. Additionally, dead biomass was investigated after four weeks of incubation. The maximum of metal removal was reached after one week. Up to 80% of both Al and Cu, and more than 60% of U was shown to be removed from the solution. High concentrations of metals could be bound to the biomass, as for example 2.2 mg/g U. The strains could survive four weeks of incubation. Distinct and different patterns of rare earth elements of the inoculated and non-inoculated AMD water were observed. Changes in REE patterns hint at different binding types of heavy metals regarding incubation time and metabolic activity of the cells. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ironstones of the Olary Block, South Australia: the use of RNAA and INAA to understand their genesis.

Energy Technology Data Exchange (ETDEWEB)

Plimer, I R [Melbourne Univ., Parkville, VIC (Australia); Lottermoser, B G; Ashley, P M; Lawrie, D C [New England Univ., Armidale, NSW (Australia). Dept. of Geology

1997-12-31

Reactor neutron activation analysis (RNAA) , instrumental neutron activation analysis (INAA) and electron microprobe analysis of ironstones and barite from the Olary Block indicate that these deposits are geochemically similar to modem and ancient submarine hydrothermal precipitates. Geochemical analyses generally show low Mn, Pb, Zn, As and Sb concentrations and elevated Au and Cu values. Major (Al, Si) and trace (REE, Th, U, PGEs) element data show that the ironstones and barite rocks are of hydrothermal origin and that mixing occurred between oxidised (and possibly hypersaline) surficial waters and a hydrothermal fluid similar to that from modem sites of submarine exhalation. Such geochemical similarities imply rapid burial in the volcano-sedimentary pile or sub-seafloor replacement. The REE patterns in the iron formations demonstrate a range from low temperature reduced hydrothermal precipitates, seawater and oxidised hydrothermal precipitates. Geochemical signatures are due to precipitation from hydrothermal fluids of lower temperature with further influence by prolonged exposure to the overlying water column and subaqueous oxidation. 7 refs.

Ironstones of the Olary Block, South Australia: the use of RNAA and INAA to understand their genesis.

Energy Technology Data Exchange (ETDEWEB)

Plimer, I.R. [Melbourne Univ., Parkville, VIC (Australia); Lottermoser, B.G.; Ashley, P.M.; Lawrie, D.C. [New England Univ., Armidale, NSW (Australia). Dept. of Geology

1996-12-31

Reactor neutron activation analysis (RNAA) , instrumental neutron activation analysis (INAA) and electron microprobe analysis of ironstones and barite from the Olary Block indicate that these deposits are geochemically similar to modem and ancient submarine hydrothermal precipitates. Geochemical analyses generally show low Mn, Pb, Zn, As and Sb concentrations and elevated Au and Cu values. Major (Al, Si) and trace (REE, Th, U, PGEs) element data show that the ironstones and barite rocks are of hydrothermal origin and that mixing occurred between oxidised (and possibly hypersaline) surficial waters and a hydrothermal fluid similar to that from modem sites of submarine exhalation. Such geochemical similarities imply rapid burial in the volcano-sedimentary pile or sub-seafloor replacement. The REE patterns in the iron formations demonstrate a range from low temperature reduced hydrothermal precipitates, seawater and oxidised hydrothermal precipitates. Geochemical signatures are due to precipitation from hydrothermal fluids of lower temperature with further influence by prolonged exposure to the overlying water column and subaqueous oxidation. 7 refs.

Rare earth elements and uranium in fountain waters from different towns of the Iron Quadrangle, MG, Brazil

International Nuclear Information System (INIS)

Ferreira, Claudia A.; Palmieri, Helena E.L.; Menezes, Maria Angela de B.C.

2015-01-01

Rare earth elements (REE) and uranium were evaluated in 34 fountain waters collected in different towns of the Iron Quadrangle (IQ), Minas Gerais, Brazil. The IQ is one of the largest and most well-known mineral deposits in the world. Not only extensive iron deposits but also hydrothermal gold deposits are found in this region. Because of the toxicological properties of REE, monitoring of groundwater which is used for drinking water may be useful if relatively high concentrations of REE are expected. The total REE (ΣREE) concentrations in fountain water range from 3 to 33395 ng L -1 . It was observed that fountains with a pH value below 5 presented higher concentration values of the determined elements proposed in this work. This is due to the fact that waters exhibiting low pH values enhance the dissolution of these elements. Moreover, for uranium the values ranged from less than < 2 to 540 ng L -1 . The highest concentrations in waters were observed only in four cities. Statistical methods such as Pearson correlation, PCA and HCA analysis were applied to the data set to shed some light on the behavior of the elements in water in this study. Three major groups with similar characteristics were identified and six diagrams of REE signatures in fountain waters were plotted according to their groupings of subdivisions. Using the REE-Post-Archean Australian Shale (PAAS) normalized patterns it was possible to verify presence of distinct REE signatures and recognize that the two samples belong to the same aquifer type. (author)

Regional Variations of REE Patterns in Sediments from Active Plate Boundaries

DEFF Research Database (Denmark)

Kunzendorf, H.; Stoffers, P.; Gwozdz, R.

1988-01-01

About 150 sediment samples from mid-ocean ridges (East Pacific Rise, Central Indian Ocean Ridge, Carlsberg Ridge and the Red Sea) and from a back-arc spreading environment (Lau Basin) were analyzed by instrumental neutron activation. A ratio method for rare-earth elements involving a plot...... of elemental ratios of Ce/La and Ce/Yb is proposed to characterize marine sediments. In the characterization plot East Pacific Rise and Lau Basin sediments occupy distinct fields in the plot suggesting hydrothermal overprint, while sediments from the Central Indian Ocean and the Carlsberg Ridge plot...

Comparative toxicities of selected rare earth elements: Sea urchin embryogenesis and fertilization damage with redox and cytogenetic effects

Energy Technology Data Exchange (ETDEWEB)

Pagano, Giovanni, E-mail: gbpagano@tin.it [“Federico II” University of Naples, Environmental Hygiene, I-80126 Naples (Italy); Guida, Marco; Siciliano, Antonietta [“Federico II” University of Naples, Environmental Hygiene, I-80126 Naples (Italy); Oral, Rahime [Ege University, Faculty of Fisheries, TR-35100 Bornova, İzmir (Turkey); Koçbaş, Fatma [Celal Bayar University, Faculty of Arts and Sciences, Department of Biology, TR-45140 Yunusemre, Manisa (Turkey); Palumbo, Anna; Castellano, Immacolata; Migliaccio, Oriana [Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples (Italy); Thomas, Philippe J. [Environment Canada, Science & Technology Branch, National Wildlife Research Center – Carleton University, Ottawa, Ontario, Canada K1A 0H3 (Canada); Trifuoggi, Marco [“Federico II” University of Naples, Department of Chemical Sciences, I-80126 Naples (Italy)

2016-05-15

Background: Broad-ranging adverse effects are known for rare earth elements (REE), yet only a few studies tested the toxicity of several REE, prompting studies focusing on multi-parameter REE toxicity. Methods: Trichloride salts of Y, La, Ce, Nd, Sm, Eu and Gd were tested in Paracentrotus lividus sea urchin embryos and sperm for: (1) developmental defects in either REE-exposed larvae or in the offspring of REE-exposed sperm; (2) fertilization success; (3) mitotic anomalies in REE-exposed embryos and in the offspring of REE-exposed sperm, and (4) reactive oxygen species (ROS) formation, and malondialdehyde (MDA) and nitric oxide (NO) levels. Results: REEs affected P. lividus larvae with concentration-related increase in developmental defects, 10{sup −6} to 10{sup −4} M, ranking as: Gd(III)>Y(III)>La(III)>Nd(III)≅Eu(III)>Ce(III)≅Sm(III). Nominal concentrations of REE salts were confirmed by inductively coupled plasma mass spectrometry (ICP-MS). Significant increases in MDA levels, ROS formation, and NO levels were found in REE-exposed embryos. Sperm exposure to REEs (10{sup −5} to 10{sup −4} M) resulted in concentration-related decrease in fertilization success along with increase in offspring damage. Decreased mitotic activity and increased aberration rates were detected in REE-exposed embryos and in the offspring of REE-exposed sperm. Conclusion: REE-associated toxicity affecting embryogenesis, fertilization, cytogenetic and redox endpoints showed different activities of tested REEs. Damage to early life stages, along with redox and cytogenetic anomalies should be the focus of future REE toxicity studies. - Highlights: • Seven rare earth elements exerted different effects on sea urchin early life stages. • Embryo-, spermio- and mitotoxicity, and oxidative/ nitrosative stress were found. • Nominal vs. analytical REE concentrations were checked. • Comparative toxicities were evaluated for the different REE.

Comparative toxicities of selected rare earth elements: Sea urchin embryogenesis and fertilization damage with redox and cytogenetic effects

International Nuclear Information System (INIS)

Pagano, Giovanni; Guida, Marco; Siciliano, Antonietta; Oral, Rahime; Koçbaş, Fatma; Palumbo, Anna; Castellano, Immacolata; Migliaccio, Oriana; Thomas, Philippe J.; Trifuoggi, Marco

2016-01-01

Background: Broad-ranging adverse effects are known for rare earth elements (REE), yet only a few studies tested the toxicity of several REE, prompting studies focusing on multi-parameter REE toxicity. Methods: Trichloride salts of Y, La, Ce, Nd, Sm, Eu and Gd were tested in Paracentrotus lividus sea urchin embryos and sperm for: (1) developmental defects in either REE-exposed larvae or in the offspring of REE-exposed sperm; (2) fertilization success; (3) mitotic anomalies in REE-exposed embryos and in the offspring of REE-exposed sperm, and (4) reactive oxygen species (ROS) formation, and malondialdehyde (MDA) and nitric oxide (NO) levels. Results: REEs affected P. lividus larvae with concentration-related increase in developmental defects, 10 −6 to 10 −4 M, ranking as: Gd(III)>Y(III)>La(III)>Nd(III)≅Eu(III)>Ce(III)≅Sm(III). Nominal concentrations of REE salts were confirmed by inductively coupled plasma mass spectrometry (ICP-MS). Significant increases in MDA levels, ROS formation, and NO levels were found in REE-exposed embryos. Sperm exposure to REEs (10 −5 to 10 −4 M) resulted in concentration-related decrease in fertilization success along with increase in offspring damage. Decreased mitotic activity and increased aberration rates were detected in REE-exposed embryos and in the offspring of REE-exposed sperm. Conclusion: REE-associated toxicity affecting embryogenesis, fertilization, cytogenetic and redox endpoints showed different activities of tested REEs. Damage to early life stages, along with redox and cytogenetic anomalies should be the focus of future REE toxicity studies. - Highlights: • Seven rare earth elements exerted different effects on sea urchin early life stages. • Embryo-, spermio- and mitotoxicity, and oxidative/ nitrosative stress were found. • Nominal vs. analytical REE concentrations were checked. • Comparative toxicities were evaluated for the different REE.

Signature of breccia complex/iron oxide- type U-REE mineralisation in the Khairagarh basin with special reference to Dongargaon- Lohara area, central India

International Nuclear Information System (INIS)

Hansoti, S.K.; Sinha, D.K.

1995-01-01

The Khairagarh basin having late Archaean- early Proterozoic basement is filled up by middle Proterozoic Khairagarh group volcano - sedimentary sequence, laid in the Kotri rift zone (KRZ) with imprints of repetitive volcanic, plutonic and tectonic activities. A strong thermal imprint of ∼ 1.5 Ga has been recorded in rocks of the basin that could be an effect of copious outpouring of basalts, dacites, ignimbrites, together with the emplacements of stocks of gabbros, gabbroic dolerites, dolerites, granites, granophyres, felsites, aplites, and quartz veins. Some of the basement rocks are enriched in Fe, Cu and other base metals and have been emplaced and assimilated by the volcano- plutonic rocks of the Nandgaon group and Malanjkhand granitoids. The Nandgaon group rocks and the Malanjkhand granitoids have anomalous intrinsic abundance of U, REE, Cu, Fe and quite a few metals in different sectors. Thermo-tectonic (∼ 1.5 Ga) reactivation event(s) along the KRZ apart from facilitating formation of agglomerates, ignimbrites and tectonic breccias has promoted emplacement of plutonic and subvolcanic phases and their metasomatising and hydrothermal metal bearing fluids. In the Malanjkhand complex sector Cu±Mo±Fe±Ag±Au±REE±Zn metallisation and in the Dongargarh Massif sector U±Th±F±Fe±Pb±Zn±Cu±REE±Zr metallisation are manifested. The detection of Fe+U+REE ±Cu±Ni metallisation in the Bortalao sandstones of the Dongargaon - Lohara area, located in between Malanjkhand ore zone and the Chandidongri (Dongargarh granite hosted) fluorite-rich and Pb±Zn±Cu±U - bearing ore zone, considered to lie on the same (Malanjkhand - Chandidongri) fault/shear lineament is rated highly significant. This observation supports the prognosis that the terrain lying in between the Dongargarh Massif and the Malanjkhand Granitoid complex should be the locus for the mixing of the respective metal bearing fluids and such a terrain therefore should be considered as a first order

REE and Isotopic Compositions of Lunar Basalts Demonstrate Partial Melting of Hybridized Mantle Sources after Cumulate Overturn is Required

Science.gov (United States)

Dygert, N. J.; Liang, Y.

2017-12-01

Lunar basalts maintain an important record of the composition of the lunar interior. Much of our understanding of the Moon's early evolution comes from studying their petrogenesis. Recent experimental work has advanced our knowledge of major and trace element fractionation during lunar magma ocean (LMO) crystallization [e.g., 1-3], which produced heterogeneous basalt sources in the Moon's mantle. With the new experimental constraints, we can evaluate isotopic and trace element signatures in lunar basalts in unprecedented detail, refining inferences about the Moon's dynamic history. Two petrogenetic models are invoked to explain the compositions of the basalts. The assimilation model argues they formed as primitive melts of early LMO cumulates that assimilated late LMO cumulates as they migrated upward. The cumulate overturn model argues that dense LMO cumulates sank into the lunar interior, producing hybridized sources that melted to form the basalts. Here we compare predicted Ce/Yb and Hf and Nd isotopes of partial melts of LMO cumulates with measured compositions of lunar basalts to evaluate whether they could have formed by end-member petrogenetic models. LMO crystallization models suggest all LMO cumulates have chondrite normalized Ce/Yb 1.5; these could not have formed by assimilation of any LMO cumulate or residual liquid (or KREEP basalt, which has isotopically negative ɛNd and ɛHf). In contrast, basalt REE patterns and isotopes can easily be modeled assuming partial melting of hybridized mantle sources, indicating overturn may be required. A chemical requirement for overturn independently confirms that late LMO cumulates are sufficiently low in viscosity to sink into the lunar interior, as suggested by recent rock deformation experiments [4]. Overturned, low viscosity late LMO cumulates would be relatively stable around the core [5]. High Ce/Yb basalts require that overturned cumulates were mixed back into the overlying mantle by convection within a few

Study on speciation of rare earth elements in soil

International Nuclear Information System (INIS)

Wang Yuqi; Sun Jingxin; Chen Hongmin; Guo Fanqing; Wang Lijun; Zhang Shen

1996-01-01

The contents of rare earth elements (REE) in red soil, yellow brown soil and leached chernozem are studied. After extracted sequentially, REE in these soils are fractionated into seven forms, i.e., (I) water soluble, (II) exchangeable, (III) loosely bound to organic mater, (IV) bound to carbonate and specifically absorbed, (V) bound to Fe-Mn oxides, (VI) tightly bound to organic matter and (VII) residual forms. The contents of REE in every form are determined by NAA (neutron activation analysis). The results show that REE in soils mainly exist in residual form and REE in soluble forms are very limited (<7%)

Magnesium and Titanium Isotopic Compositions of an Unusual Hibonite-Perovskite Refractory Inclusion from Allende: It Is Fun

Science.gov (United States)

Liu, M.-C.; Keller, L. P.; McKeegan, K. D.

2016-01-01

of (sup 26) Al. Delta (sup 25) Mg (mass-dependent fractionation) in hibonite is approximately -5 per mille per atomic mass unit relative to Madagascar hibonite, but is not well constrained for perovskite due to very large uncertainties owing to extremely low Mg contents. Similar to Mg isotopes, SHAL hibonite and perovskite show essentially the same Ti isotopic compositions, with anomalies in (sup 50) Ti of approximately 14 per mille, but the former shows greater Ti isotope fractionation than the latter (2.5 per mille per atomic mass unit versus 0 per mille). Discussion and Conclusions: The Al-Mg and Ti isotopic compositions of SHAL hibonite are consistent with those of HAL, suggesting that SHAL hibonite is a FUN inclusion and likely formed prior to homogenization of (sup 26) Al and Ti isotope variations in the solar nebula. However, the formation mechanisms for SHAL and HAL differ, given the differences in the REE patterns and degrees of oxygen mass-dependent fractionation. The Group-II to Group-III like REE patterns, the Yb depletions, and negative delta (sup 25) Mg observed in SHAL hibonite are all consistent with condensation of the hibonite precursor in a reducing environment.. The lack of large Ce depletions in SHAL hibonite implies that distillation processes that fractionated hibonite's oxygen isotopes must have taken place under a reducing condition, but the extent to which SHAL hibonite was distilled appears to be less than HAL because of the smaller degree of oxygen mass-dependent fractionation. The perovskite shares essentially the same Ti and Mg isotopic compositions as hibonite and probably formed in the same reservoir.. The ultrarefractory REE pattern seen in perovskite likely resulted from gas-solid fractionation which depleted HREEs in this reservoir. This process also explains why SHAL hibonite is generally depleted in HREEs relative to LREEs.

Turtle Flexion Reflex Motor Patterns Show Windup, Mediated Partly by L-type Calcium Channels

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Keith P. Johnson

2017-10-01

Full Text Available Windup is a form of multisecond temporal summation in which identical stimuli, delivered seconds apart, trigger increasingly strong neuronal responses. L-type Ca2+ channels have been shown to play an important role in the production of windup of spinal cord neuronal responses, initially in studies of turtle spinal cord and later in studies of mammalian spinal cord. L-type Ca2+ channels have also been shown to contribute to windup of limb withdrawal reflex (flexion reflex in rats, but flexion reflex windup has not previously been described in turtles and its cellular mechanisms have not been studied. We studied windup of flexion reflex motor patterns, evoked with weak mechanical and electrical stimulation of the dorsal hindlimb foot skin and assessed via a hip flexor (HF nerve recording, in spinal cord-transected and immobilized turtles in vivo. We found that an L-type Ca2+ channel antagonist, nifedipine, applied at concentrations of 50 μM or 100 μM to the hindlimb enlargement spinal cord, significantly reduced windup of flexion reflex motor patterns, while lower concentrations of nifedipine had no such effect. Nifedipine similarly reduced the amplitude of an individual flexion reflex motor pattern evoked by a stronger mechanical stimulus, in a dose-dependent manner, suggesting that L-type Ca2+ channels contribute to each flexion reflex as well as to multisecond summation of flexion reflex responses in turtles. We also found that we could elicit flexion reflex windup consistently using a 4-g von Frey filament, which is not usually considered a nociceptive stimulus. Thus, it may be that windup can be evoked by a wide range of tactile stimuli and that L-type calcium channels contribute to multisecond temporal summation of diverse tactile stimuli across vertebrates.

Rare Earth Elements (La, Ce, Pr, Nd, and Sm from a Carbonatite Deposit: Mineralogical Characterization and Geochemical Behavior

Directory of Open Access Journals (Sweden)

Mohamed Edahbi

2018-02-01

Full Text Available Geochemical characterization including mineralogical measurements and kinetic testing was completed on samples from the Montviel carbonatite deposit, located in Quebec (Canada. Three main lithological units representing both waste and ore grades were sampled from drill core. A rare earth element (REE concentrate was produced through a combination of gravity and magnetic separation. All samples were characterized using different mineralogical techniques (i.e., quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN, X-ray diffraction (XRD, and scanning electron microscopy with X-ray microanalysis (SEM-EDS in order to quantify modal mineralogy, liberation, REE deportment and composition of REE-bearing phases. The REE concentrate was then submitted for kinetic testing (weathering cell in order to investigate the REE leaching potential. The mineralogical results indicate that: (i the main REE-bearing minerals in all samples are burbankite, kukharenkoite-Ce, monazite, and apatite; (ii the samples are dominated by REE-free carbonates (i.e., calcite, ankerite, and siderite; and (iii LREE is more abundant than HREE. Grades of REE minerals, sulfides and oxides are richer in the concentrate than in the host lithologies. The geochemical test results show that low concentrations of light REE are leached under kinetic testing conditions (8.8–139.6 µg/L total light REE. These results are explained by a low reactivity of the REE-bearing carbonates in the kinetic testing conditions, low amounts of REE in solids, and by precipitation of secondary REE minerals.

Development of the determination method of rare earth elements in seawater by ICP-MS with an on-line preconcentration column of improved iminodiacetate resin and its application to Tokyo Bay seawater

International Nuclear Information System (INIS)

Tsuneto, Atsushi; Suzuki, Yoshinari; Furuta, Naoki; Furusho, Yoshiaki

2009-01-01

In order to determine rare earth elements (REEs) in seawater by using inductively coupled plasma mass spectrometry (ICP-MS) with an on-line preconcentration column, we used the improved iminodiacetate chelate resin (MetaSEP ME-2) that had a cation-type alkyl group. Its operating conditions were optimized, and the recoveries of REEs and the removal rates of matrix elements were compared with other resins. Ca and Mg were removed more efficiently under a buffer solution of pH 5.0. The removal efficiencies of Ca and Mg using MetaSEP ME-2 were better than those using other resins. We determined REEs in a seawater reference material (NASS-5) with MetaSEP ME-2. The obtained results were in good agreement with the reference values. We applied this method to the determination of REEs in seawater collected from Tokyo Bay, and evaluated the distribution patterns of REEs. Consequently, the positive anomaly of Gd in the small-molecule fraction was observed. The positive anomaly of Gd can be attributed to the outflow of Gd compounds, which are used for a magnetic resonance imaging contrast medium. (author)

Application of stochastic approach based on Monte Carlo (MC) simulation for life cycle inventory (LCI) of the rare earth elements (REEs) in beneficiation rare earth waste from the gold processing: case study

Science.gov (United States)

Bieda, Bogusław; Grzesik, Katarzyna

2017-11-01

The study proposes an stochastic approach based on Monte Carlo (MC) simulation for life cycle assessment (LCA) method limited to life cycle inventory (LCI) study for rare earth elements (REEs) recovery from the secondary materials processes production applied to the New Krankberg Mine in Sweden. The MC method is recognizes as an important tool in science and can be considered the most effective quantification approach for uncertainties. The use of stochastic approach helps to characterize the uncertainties better than deterministic method. Uncertainty of data can be expressed through a definition of probability distribution of that data (e.g. through standard deviation or variance). The data used in this study are obtained from: (i) site-specific measured or calculated data, (ii) values based on literature, (iii) the ecoinvent process "rare earth concentrate, 70% REO, from bastnäsite, at beneficiation". Environmental emissions (e.g, particulates, uranium-238, thorium-232), energy and REE (La, Ce, Nd, Pr, Sm, Dy, Eu, Tb, Y, Sc, Yb, Lu, Tm, Y, Gd) have been inventoried. The study is based on a reference case for the year 2016. The combination of MC analysis with sensitivity analysis is the best solution for quantified the uncertainty in the LCI/LCA. The reliability of LCA results may be uncertain, to a certain degree, but this uncertainty can be noticed with the help of MC method.

Regularities of the extraction of rare earth elements with triisoamyl phosphate

International Nuclear Information System (INIS)

Danilov, N.A.; Korpusov, G.V.; Utkina, O.V.; Pogorel'skaya, S.A.

1988-01-01

A study was made on practically important regularities of rare earth element (REE) extraction by triisoamyl phosphate (TiAP): isotherms of REE extraction, effect of REE and salting-out agents concentrations in aqueous phase on REE distribution and separation coefficients, effect of HNO 3 concentration and others. The data obtained show, that TiAP is the typical representative of neutral organophosphoric compounds, and its extraction properties are close to those of TBP. The third phase doesn't form during REE nitrate extraction by TiAP solutions in saturated hydrocarbons of any concentration. High selectivity is not observed during separation of cerium subgroup REE by TiAP. TiAP losses are lower than those of TBP due to lower TiAP solubility in water

Herbarium specimens show patterns of fruiting phenology in native and invasive plant species across New England.

Science.gov (United States)

Gallinat, Amanda S; Russo, Luca; Melaas, Eli K; Willis, Charles G; Primack, Richard B

2018-01-01

Patterns of fruiting phenology in temperate ecosystems are poorly understood, despite the ecological importance of fruiting for animal nutrition and seed dispersal. Herbarium specimens represent an under-utilized resource for investigating geographical and climatic factors affecting fruiting times within species, patterns in fruiting times among species, and differences between native and non-native invasive species. We examined over 15,000 herbarium specimens, collected and housed across New England, and found 3159 specimens with ripe fruits, collected from 1849-2013. We examined patterns in fruiting phenology among 37 native and 18 invasive woody plant species common to New England. We compared fruiting dates between native and invasive species, and analyzed how fruiting phenology varies with temperature, space, and time. Spring temperature and year explained a small but significant amount of the variation in fruiting dates. Accounting for the moderate phylogenetic signal in fruiting phenology, invasive species fruited 26 days later on average than native species, with significantly greater standard deviations. Herbarium specimens can be used to detect patterns in fruiting times among species. However, the amount of intraspecific variation in fruiting times explained by temporal, geographic, and climatic predictors is small, due to a combination of low temporal resolution of fruiting specimens and the protracted nature of fruiting. Later fruiting times in invasive species, combined with delays in autumn bird migrations in New England, may increase the likelihood that migratory birds will consume and disperse invasive seeds in New England later into the year. © 2018 Botanical Society of America.

Sustainability of rare earth elements chain: from production to food - a review.

Science.gov (United States)

Turra, Christian

2018-02-01

Rare earth elements (REE) are a group of chemical elements that include lanthanoids (lanthanum to lutetium), scandium and yttrium. In the last decades, the REE demand in the industry and other areas has increased significantly. In general, REE have shown low concentrations in soils, plants, water and atmosphere, but they may accumulate in such environments due to anthropogenic inputs. In areas where there is REE contamination, the slow accumulation of these elements in the environment could become problematic. Many studies have shown environmental areas contaminated with REE and their toxic effects. Thus, it is important to review, in order to improve the current understanding of these elements in the environment, showing the effects of REE exposure in mining, soil, water, plants and food. Besides, there are few suppliers and a limited quantity of these elements in the world. This paper suggests options to improve the sustainability management of REE chain.

On the uniqueness of fully informative rational expectations equilibria

OpenAIRE

Peter DeMarzo; Costis Skiadas

1998-01-01

This paper analyzes two equivalent equilibrium notions under asymmetric information: risk neutral rational expectations equilibria (rn-REE), and common knowledge equilibria. We show that the set of fully informative rn-REE is a singleton, and we provide necessary and sufficient conditions for the existence of partially informative rn-REE. In a companion paper (DeMarzo and Skiadas (1996)) we show that equilibrium prices for the larger class of quasi-complete economies can be characterized as r...

Hydrochemical study of an arsenic-contaminated plain in Guandu, north Taiwan

Science.gov (United States)

Hsiao, Yu-Hsiang

2015-04-01

Arsenic pollution in Guandu Plain, north Taiwan is a critical issue due to highly developed anthropogenic activities. It was considered that arsenic was carried in by surface water system. Two major rivers, Huanggang Creek and South Huang Greek, flow through Guandu Plain. Both creeks originate from Tatung Volcano Group, which is extensively active in post-volcanic activities. In this study, the hydrochemistry along the two major rivers was studied for tracing the source of arsenic pollution in Guandu Plain. The pH values in the upstream water are in the range from 6 to 8 but dramatically decrease down to 2-4.5 in the downstream area. It can be concluded that the creeks are recharged with very low pH geothermal water. In addition, arsenic shows a different spatial distribution. In Huanggang Creek, arsenic concentration is much higher, about 200 ppb to 500 ppb, in the downstream than in the upstream while arsenic concentration is extremely low, below 1 ppb, in the downstream of South Huang Greek. The geochemical results show that rare earth elements (REEs) are depleted in the upstream both in Huanggang creek and South Huang creek, and the NASC-normalized ratios of heavy to light REE (Lu/La) in the upstream are very close to 1. This demonstrates that the upstream water is geochemically dominated by the interaction between water and sedimentary rock. In the downstream, the NASC-normalized REE pattern shows a quit different type which is depleted in light REEs (much higher Lu/La ratio). It is well known that igneous rock is depleted in light REEs; therefore, arsenic is possibly volcanic origin. In this study, PHREEQC, a thermodynamic modeling program, was also utilized to calculate the saturation index (SI) of hydrous ferric oxide (HFO), which can effectively scavenge arsenic in water. The results demonstrate that SI of HFO is mainly controlled by pH in this study. When pH is greater than 3.5, HFO start to precipitate and remove arsenic from water. Therefore, it is

Rare Earth Element Transfer from Soil to Navel Orange Pulp (Citrus sinensis Osbeck cv. Newhall) and the Effects on Internal Fruit Quality

Science.gov (United States)

Cheng, Jinjin; Ding, Changfeng; Li, Xiaogang; Zhang, Taolin; Wang, Xingxiang

2015-01-01

The effects of soil rare earth element (REE) on navel orange quality and safety in rare earth ore areas have gained great attention. This study investigated the transfer characteristics of REE from soil to navel orange pulp (Citrus sinensis Osbeck cv. Newhall) and examined the effects of soil REE on internal fruit quality in Xinfeng County, Jiangxi province, China. Path analysis showed that soil REE, pH, cation exchange capacity (CEC), and Fe oxide (Feox) significantly affected pulp REE concentrations. A Freundlich-type prediction model for pulp REE was established: log[REEpulp] = -1.036 + 0.272 log[REEsoil] - 0.056 pH - 0.360 log[CEC] + 0.370 log[Feox] (n = 114, R2 = 0.60). From the prediction model, it was inferred that even when soil REE and Feox were as high as 1038 mg kg-1 and 96.4 g kg-1, respectively, and pH and CEC were as low as 3.75 and 5.08 cmol kg-1, respectively, pulp REE concentrations were much lower than the food limit standard. Additionally, soil REE levels were significantly correlated with selected fruit quality indicators, including titratable acidity (r = 0.52, P fruit quality. PMID:25806821

Off-line separation and determination of rare earth elements associated with chloroplast pigments of hyperaccumulator Dicranopteris dichotoma by normal-phase liquid chromatography and ICP-MS.

Science.gov (United States)

Wei, Z G; Hong, F S; Yin, M; Li, H X; Hu, F; Zhao, G W; Wong, J W C

2004-10-01

An off-line normal-phase liquid chromatography-ICP-MS method has been used for separation and determination of the rare earth elements (REE) associated with chloroplast pigments of Dicranopteris dichotoma. The stability of REE-bound pigments was tested, and almost no destruction of REE-bound pigments occurred during the so-called normal-phase liquid chromatography. The accumulated free REE ions on the microcrystalline cellulose column were cleaned by elution with 5 mmol L(-1) 2-ethylhexyl hydrogen 2-ethylhexylphosphonate (P507), to avoid exchange of these free ions with metals from the pigments. When these precautions were taken, the method was applied to the study of REE-bound pigments in D. dichotoma. ICP-MS results showed REE were present in chlorophylls and lutein, although REE concentrations in carotene and pheophytin were both below procedural blank levels. By careful analysis of the eluate fractions containing chlorophyll a it was found that REE-bound chlorophyll a in D. dichotoma was slightly enriched in the fractions with relatively short retention time. Results indicated that the retention time of REE-bound chlorophyll a might be slightly less than that of magnesium chlorophyll a, and REE-bound chlorophylls might be of relatively low polarity in comparison with magnesium bound chlorophylls. This phenomenon could be explained by the special double-decker sandwich-structure of REE-bound chlorophylls, as was reported by us and other authors. On the basis of these results we preferred to consider that REE can replace magnesium in chlorophyll a of D. dichotoma, and that the role of REE-bound chlorophylls in photosynthesis cannot be neglected. These data might be useful for understanding of both the properties of REE-bound pigments and the effect of REE on plant photosynthesis.

Physical processes in thin-film electroluminescent structures based on ZnS:Mn showing self-organized patterns

International Nuclear Information System (INIS)

Zuccaro, S.; Raker, Th.; Niedernostheide, F.-J.; Kuhn, T.; Purwins, H.-G.

2003-01-01

Physical processes in thin ZnS:Mn films and their relation to the formation of dynamical patterns in the electroluminescence of AC driven films are investigated. The technique of photo-depolarization-spectroscopy is used to investigate defect states in these films and it is shown that specific features in the spectra correlate with the observed self-organized patterns. Furthermore, the time dependence of the dissipative current is measured at the same samples and compared with current waveforms obtained from numerical simulations of a drift-diffusion model. The results are used to discuss the origin of the self-organized processes in ZnS:Mn-films

Determination of rare earth elements in Solanum lycocarpum in `Cerrado de Emas`- Pirassununga, State of Sao Paulo, Brazil, by neutron activation analysis

Energy Technology Data Exchange (ETDEWEB)

Piorino-Maria, S.; Figueiredo, A.M.G.; Ticianelli, R.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Ceccantini, G. [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil)

1997-10-01

In the present work, the rare earth elements concentration (REE) in plant leaves of the species Solanum lycocarpum from `Cerrado de Emas`, Pirassununga, Sao Paulo, and the soil where they have grown up, was determined by using instrumental neutron activation analysis. The obtained values for most of the light REE (La, Ce, Nd) were higher than the reference values for REE in plants. These results suggest that the light REE are more available in the soil than the heavy REE. The concentration of REE in the plant and the soil were normalized to chondrite contents, showing in the soil diagram a negative anomaly for the concentration of Eu and a positive anomaly for the concentration of Ce, which were not observed in the plant diagram. (author). 11 refs., 1 fig., 2 tabs.

Determination of rare earth elements in Solanum lycocarpum in 'Cerrado de Emas'- Pirassununga, State of Sao Paulo, Brazil, by neutron activation analysis

International Nuclear Information System (INIS)

Piorino-Maria, S.; Figueiredo, A.M.G.; Ticianelli, R.B.; Ceccantini, G.

1997-01-01

In the present work, the rare earth elements concentration (REE) in plant leaves of the species Solanum lycocarpum from 'Cerrado de Emas', Pirassununga, Sao Paulo, and the soil where they have grown up, was determined by using instrumental neutron activation analysis. The obtained values for most of the light REE (La, Ce, Nd) were higher than the reference values for REE in plants. These results suggest that the light REE are more available in the soil than the heavy REE. The concentration of REE in the plant and the soil were normalized to chondrite contents, showing in the soil diagram a negative anomaly for the concentration of Eu and a positive anomaly for the concentration of Ce, which were not observed in the plant diagram. (author). 11 refs., 1 fig., 2 tabs

Economic Assessment for Recycling Critical Metals From Hard Disk Drives Using a Comprehensive Recovery Process

Science.gov (United States)

Nguyen, Ruby Thuy; Diaz, Luis A.; Imholte, D. Devin; Lister, Tedd E.

2017-09-01

Since the 2011 price spike of rare earth elements (REEs), research on permanent magnet recycling has blossomed globally in an attempt to reduce future REE criticality. Hard disk drives (HDDs) have emerged as one feasible feedstock for recovering valuable REEs such as praseodymium, neodymium, and dysprosium. Nevertheless, current processes for recycling electronic waste only focus on certain metals as a result of feedstock and metal price uncertainties. In addition, there is a perception that recycling REEs is unprofitable. To shed some light on the economic viability of REE recycling from U.S. HDDs, this article combines techno-economic information of an electro-hydrometallurgical process with end-of-life HDD availability in a simulation model. The results showed that adding REE recovery to an HDD base and precious metal recovery process was profitable given current prices. Recovered REEs from U.S. HDDs could meet up to 5.2% rest-of-world (excluding China) neodymium magnet demand. Feedstock, aluminum, and gold prices are key factors to recycling profitability. REEs contributed 13% to the co-recycling profit.

Rare earth elements and neodymium isotopes in sedimentary organic matter

Science.gov (United States)

Freslon, Nicolas; Bayon, Germain; Toucanne, Samuel; Bermell, Sylvain; Bollinger, Claire; Chéron, Sandrine; Etoubleau, Joel; Germain, Yoan; Khripounoff, Alexis; Ponzevera, Emmanuel; Rouget, Marie-Laure

2014-09-01

We report rare earth element (REE) and neodymium (Nd) isotope data for the organic fraction of sediments collected from various depositional environments, i.e. rivers (n = 25), estuaries (n = 18), open-ocean settings (n = 15), and cold seeps (n = 12). Sedimentary organic matter (SOM) was extracted using a mixed hydrogen peroxide/nitric acid solution (20%-H2O2-0.02 M-HNO3), after removal of carbonate and oxy-hydroxide phases with dilute hydrochloric acid (0.25 M-HCl). A series of experimental tests indicate that extraction of sedimentary organic compounds using H2O2 may be complicated occasionally by partial dissolution of sulphide minerals and residual carbonates. However, this contamination is expected to be minor for REE because measured concentrations in H2O2 leachates are about two-orders of magnitude higher than in the above mentioned phases. The mean REE concentrations determined in the H2O2 leachates for samples from rivers, estuaries, coastal seas and open-ocean settings yield relatively similar levels, with ΣREE = 109 ± 86 ppm (mean ± s; n = 58). The organic fractions leached from cold seep sediments display even higher concentration levels (285 ± 150 ppm; mean ± s; n = 12). The H2O2 leachates for most sediments exhibit remarkably similar shale-normalized REE patterns, all characterized by a mid-REE enrichment compared to the other REE. This suggests that the distribution of REE in leached sedimentary organic phases is controlled primarily by biogeochemical processes, rather than by the composition of the source from which they derive (e.g. pore, river or sea-water). The Nd isotopic compositions for organic phases leached from river sediments are very similar to those for the corresponding detrital fractions. In contrast, the SOM extracted from marine sediments display εNd values that typically range between the εNd signatures for terrestrial organic matter (inferred from the analysis of the sedimentary detrital fractions) and marine organic matter

Prediction equation of resting energy expenditure in an adult Spanish population of obese adult population.

Science.gov (United States)

de Luis, D A; Aller, R; Izaola, O; Romero, E

2006-01-01

The aim of our study was to evaluate the accuracy of the equations to estimate REE in obese patents and develop a new equation in our obese population. A population of 200 obesity outpatients was analyzed in a prospective way. The following variables were specifically recorded: age, weight, body mass index (BMI), waist circumference, and waist-to-hip ratio. Basal glucose, insulin, and TSH (thyroid-stimulating hormone) were measured. An indirect calorimetry and a tetrapolar electrical bioimpedance were performed. REE measured by indirect calorimetry was compared with REE obtained by prediction equations to obese or nonobese patients. The mean age was 44.8 +/- 16.81 years and the mean BMI 34.4 +/- 5.3. Indirect calorimetry showed that, as compared to women, men had higher resting energy expenditure (REE) (1,998.1 +/- 432 vs. 1,663.9 +/- 349 kcal/day; p consumption (284.6 +/- 67.7 vs. 238.6 +/- 54.3 ml/min; p predicted by prediction equations showed the next data; Berstein's equation (r = 0.65; p prediction equation was REE = 58.6 + (6.1 x weight (kg)) + (1,023.7 x height (m)) - (9.5 x age). The female model was REE = 1,272.5 + (9.8 x weight (kg)) - (61.6 x height (m)) - (8.2 x age). Our prediction equations showed a nonsignificant difference with REE measured (-3.7 kcal/day) with a significant correlation coefficient (r = 0.67; p prediction equations overestimated and underestimated REE measured. WHO equation developed in normal weight individuals provided the closest values. The two new equations (male and female equations) developed in our study had a good accuracy. Copyright 2006 S. Karger AG, Basel.

Bird diversity and dissimilarity show contrasting patterns along heavy metal pollution gradients in the Urals, Russia.

Science.gov (United States)

Belskii, Eugen A; Mikryukov, Vladimir S

2018-05-07

The effects of industrial pollution on bird diversity have been widely studied using traditional diversity measures, which assume all species to be equivalent. We compared species richness and Shannon index with distance-based measures of taxonomic, functional, and phylogenetic diversity (the abundance-weighted mean nearest taxon distances), which describe within-community dissimilarity at terminal branches. Analysis of dissimilarity can shed light on the processes underlying community assembly, i.e., environmental filtering decreases dissimilarity whereas competitive exclusion increases it. In the 2-year study near Karabash and Revda copper smelters in Russia, point counts of nesting birds and habitat descriptions were taken at 10 sites (40 plots) along each pollution gradient. The abundance and diversity of birds showed good repeatability in both regions. The total density of birds, number of species per plot, and Shannon diversity decreased at high toxic load in both regions. The taxonomic, functional, and phylogenetic nearest taxon distances showed the same pattern within regions. Species dissimilarity within communities increased with pollution in Karabash (due to loss of functionally similar species), but did not change in Revda (due to mass replacement of forest species by species of open habitats). Pollution-induced changes in bird communities near Karabash were greater due to the stronger deterioration of the forest ecosystems and less favorable natural conditions (more arid climate, lower diversity and vitality of the tree stand and understorey) compared to Revda. This study emphasizes the need for a multi-level approach to the analysis of bird communities using traditional indices of diversity, functional, taxonomic, or phylogenetic distances between species and environmental variables.

Comparison of the partitioning behaviours of yttrium, rare earth elements, and titanium between hydrogenetic marine ferromanganese crusts and seawater

Science.gov (United States)

Bau, M.; Koschinsky, A.; Dulski, P.; Hein, J.R.

1996-01-01

In order to evaluate details of the partitioning behaviours of Y, rare earth elements (REEs), and Ti between inorganic metal oxide surfaces and seawater, we studied the distribution of these elements in hydrogenetic marine ferromanganese (Fe-Mn) crusts from the Central Pacific Ocean. Nonphosphatized Fe-Mn crusts display shale-normalized rare earths and yttrium (REYSN) patterns (Y inserted between Dy and Ho) that are depleted in light REEs (LREEs) and which show negative anomalies for YSN, and positive anomalies for LaSN, EuSN, GdSN, and in most cases, CeSN. They show considerably smaller Y/ Ho ratios than seawater or common igneous and clastic rocks, indicating that Y and Ho are fractionated in the marine environment. Compared to P-poor crusts, REYSN patterns of phosphatized Fe-Mn crusts are similar, but yield pronounced positive YSN anomalies, stronger positive LaSN anomalies, and enrichment of the HREEs relative to the MREEs. The data suggest modification of REY during phosphatization and indicate that studies requiring primary REY distributions or isotopic ratios should be restricted to nonphosphatized (layers of) Fe-Mn crusts. Apparent bulk coefficients, KMD, describing trace metal partitioning between nonphosphatized hydrogenetic Fe-Mn crusts and seawater, are similar for Pr to Eu and decrease for Eu to Yb. Exceptionally high values of KCeD, which are similar to those of Ti, result from oxidative scavenging of Ce and support previous suggestions that Ce(IV) is a hydroxide-dominated element in seawater. Yttrium and Gd show lower KD values than their respective neighbours in the REY series. Results of modelling the exchange equilibrium between REY dissolved in seawater and REY sorbed on hydrous Fe-Mn oxides corroborate previous studies that suggested the surface complexation of REY can be approximated by their first hydroxide binding constant. Negative "anomalies" occur for stabilities of bulk surface complexes of Gd, La, and particularly Y. The differences in

Volcanism in the Sumisu Rift. Pt. 2

International Nuclear Information System (INIS)

Hochstaedter, A.G.; Gill, J.B.; Morris, J.D.

1990-01-01

A bimodal suite of volcanic rocks collected from the Sumisu Rift by ALVIN provide present day example of the first magmatic products of arc rifting during the initiation of back-arc spreading. The trace element and isotopic composition of these rocks, which are contemporaneous with island arc tholeiite lavas of the Izu-Ogasawara arc 20 km to the east, differ from those of arc rocks and N-MORB in their relative incorporation of both subduction-related and non-subduction-related components. Subduction-related components, i.e., those that distinguish volcanic arc basalts from N-MORB, are less pronounced in rift lavas than in arc lavas. Alkali and alkaline earth to high field strength element and REE ratios as well as 87 Sr/ 86 Sr are intermediate between those of N-MORB and Izu arc lavas and indicate that Sumisu Rift basalts are similar to BABB erupted in other, more mature back-arc basins. These results show that back-arc basins may begin their magmatic evolution with BABB rather than more arc-like lavas. Evidence of non-subduction related components remains after the effects of subduction related components are removed or accounted for. Compared to the arc, higher HFSE and REE concentrations, contrasting REE patterns, and ≤ε Nd in the rift reflect derivation of rift lavas from more enriched components. Although SR basalt resembles E-MORB in many trace element ratios, it is referred to as BABB because low concentrations of Nb are similar to those in volcanic arcs and H 2 O/REE and H 2 O/K 2 O exceed those of E-MORB. Differences in HREE pattern and ε Nd require that the E-MORB characteristics result from source heterogeneities and not lower degrees of melting. Enriched mantle beneath the rift may reflect enriched blobs entrained in a more depleted matrix, or injection of new, more enriched mantle. High 208 Pb/ 204 Pb and moderate 207 Pb/ 204 Pb ratios with respect to Pacific MORB also reflect ancient mantle enrichment. (orig.)

Maxillary and Mandibular First Premolars Showing Three-Cusp Pattern: An Unusual Presentation

Directory of Open Access Journals (Sweden)

Ramakant Nayak

2013-01-01

Full Text Available Dental anatomy is the study of morphology of various teeth in human dentitions. The application of dental anatomy in clinical practice is important, and dentist should have a thorough knowledge regarding the morphology of the teeth. At times as a result of genetic variation, environmental factors, diet of an individual and race, variations in the morphology of the teeth can be observed. These variations have been extensively studied by the researcher in the field of anthropology to define a particular race. The most commonly observed changes include peg-shaped laterals, shovel-shaped incisors, and extra cusp on molar. Common variations documented with regard to maxillary and mandibular first premolars are the variation in the number of roots. But the variations with respect to crown morphology are few. We report a first documented unusual presentation of maxillary and mandibular first premolars with three-cusps pattern in a female patient.

The major and trace element geochemistry of garnets from the Vargem 1 Kimberlite pipe, Minas Gerais State, Brazil

International Nuclear Information System (INIS)

Esperanca, S.; Murray, D.C.; Lambert, D.D.

1995-01-01

ICP-MS minor and trace element analysis of four single red garnets and two purple garnet composites show that: Ni contents of the bulk garnets are consistent with temperatures of equilibration in the range of 1050-1100 C; the amount of LREE enrichment appears to correlate with increasing CR contents in the garnets and, overall, the REE patterns of the six samples show normal rather than sinusoidal characteristics; relative to primitive mantle, the incompatible-element enrichment is selective across the samples but Pb shows a positive anomaly relative to La, Ce and Sr. 9 figs., 2 tabs

Rare earth elements determination in medicinal plants by Neutron Activation Analisys

International Nuclear Information System (INIS)

Goncalves, Rodolfo D.M.R.; Francisconi, Lucilaine S.; Silva, Paulo S.C. da

2013-01-01

Rare Earth Elements (REEs) have been considered nontoxic for human health and for the environment; however, the use of REEs in the development of recent technologies has increased the interest un their biological effects. Some studies related to their concentration in foodstuffs were published but REEs levels in medicinal plants are still unknown. The objective of this study was to determine the Rees concentration in the set of 59 medicinal herbs commonly used by Brazilian folk. Results showed that plants can concentrate REEs in their aerial parts, but the amount transferred to the extract of these plants is relatively low, resulting in little ingestion of these elements by the population during the extract consumption. (author)

Rare earth elements determination in medicinal plants by Neutron Activation Analisys

Energy Technology Data Exchange (ETDEWEB)

Goncalves, Rodolfo D.M.R.; Francisconi, Lucilaine S.; Silva, Paulo S.C. da, E-mail: rdmrg89@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

Rare Earth Elements (REEs) have been considered nontoxic for human health and for the environment; however, the use of REEs in the development of recent technologies has increased the interest un their biological effects. Some studies related to their concentration in foodstuffs were published but REEs levels in medicinal plants are still unknown. The objective of this study was to determine the Rees concentration in the set of 59 medicinal herbs commonly used by Brazilian folk. Results showed that plants can concentrate REEs in their aerial parts, but the amount transferred to the extract of these plants is relatively low, resulting in little ingestion of these elements by the population during the extract consumption. (author)

Sr and Nd isotopic signature of the high-K calc-alkaline magmatism of the central Ribeira belt: the Sao Pedro Granite in Lumiar, RJ; Assinatura isotopica de Sr e Nd do magmatismo calcio-alcalino de alto-K na Faixa Ribeira central: o exemplo do Granito Sao Pedro em Lumiar, RJ

Energy Technology Data Exchange (ETDEWEB)

Mendes, Julio Cezar; Medeiros, Silvia Regina de; Chaves, Eduardo Amorim, E-mail: julio@geologia.ufrj.br, E-mail: silvia@geologia.ufrj.br, E-mail: edupc2@yahoo.com.br [Departamento de Geologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro (RJ) (Brazil)

2011-09-15

In the central-northern Ribeira belt there are many granitic to granodioritic bodies showing varied shape and size, characterizing a late- to post-collisional Ca-alkaline, cordilleran I-type province. The Sao Pedro Granite occurs in the mountain region of Rio de Janeiro State as small post-collisional bodies. It presents isotropic fabric, equigranular to seriate inequigranular texture, as well as local concentration of allanite, which gives discrete composition and texture variation to the rock. The granite has a high-K calcalkaline to alkali-calcic character and weakly peraluminous nature. Despite its short geochemical variation, high Ba, Zr and Th contents besides low concentrations of MgO and CaO are noticeable. High REE contents are associated with fractionated REE patterns showing strong negative Eu anomalies. A crustal origin for the granite can be assumed by its very negative and positive .Nd and .Sr values, respectively, as well as by 87Sr/86Sr initial ratios ranging from 0,718 to 0,740. TDM ages point to paleoproterozoic source, which agrees with geological time of intensive crust generation. (author)

Application of NAA in the sort discrimination of the ancient porcelains

International Nuclear Information System (INIS)

Jia Xiuqin; Huang Zhongxiang; Han Song

2002-01-01

The neutron activation analysis is applied for analyzing the rare earth elements (REE) and trace elements in the ancient porcelains of Yao Zhou and Ru. The results show that there are differences or even significant differences between glazes and roughcasts of these two ancient porcelains in the gross amounts of REE, normalized diagrams of REE and characteristics of trace element contents, which reflecting the composition differences in glazes and roughcasts of the two kinds of porcelains. Thus, the contents of REE and trace elements can be taken for discriminating the ancient porcelains

Rare earth elements as a tool for studying the formation of cemented layers in an area affected by acid mine drainage

International Nuclear Information System (INIS)

Grawunder, Anja; Lonschinski, Martin; Merten, Dirk; Büchel, Georg

2015-01-01

Highlights: • Spatially resolved analysis of 14 rare earth elements (REE) by LA-ICP-MS. • Positive correlation of Mn contents and (positive) Ce anomalies. • Linkage of the two cemented layer’s formation to soil solution and groundwater. - Abstract: In a profile with two cemented layers sampled in an area affected by acid mine drainage, both have rare earth element (REE) signatures with positive Ce anomalies in the Post Archean Australian Shale-normalised patterns. Both cemented layers have higher contents of environmentally relevant metals (Cd, Co, Cu, Fe, Mn, U, and Zn) than the over- and underlying unconsolidated Quaternary sediments and are depleted of Al, Ca, K, and Mg. The cemented layers are enriched in middle and heavy REE, but only the bulk pattern of the lower cemented layer reveals a positive Ce anomaly. For the upper cemented layer, this positive Ce anomaly was only determined by spatially resolved laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) studies only for segments with a high abundance of Mn, occurring as Mn phases as proven by energy dispersive X-ray spectroscopy. The Mn phases are formed secondarily to the ferric cement and are especially enriched in Ce and Co. The Ce anomaly of the lower cemented layer most probably is inherited from groundwater to the ferric cement, whereas the Ce anomaly of the upper cemented layer is the result of preferential scavenging of Ce onto the Mn phases compared to other REE

Thorium, uranium and rare earth elements concentration in weathered Japanese soil samples

International Nuclear Information System (INIS)

Sahoo, Sarata Kumar; Hosoda, Masahiro; Kamagata, Sadatoshi; Sorimachi, Atsuyuki; Ishikawa, Tetsuo; Tokonami, Shinji; Uchida, Shigeo

2011-01-01

The geochemical behavior of thorium, uranium and rare earth elements (REEs) are relatively close to one another while compared to other elements in a geological environment. Radioactive elements like 232 Th and 238 U along with their decay products (e.g. 226 Ra) are present in most environmental matrices and can be transferred to living bodies by different pathways which can lead to the sources of exposure to man. For these reasons, it has been necessary to monitor those natural radionuclides in weathered soil samples to assess the possible hazards. It has been observed that granitic rocks contain higher amounts of U, Th and light REEs compared to other igneous rocks such as basalt and andesites. To better understand the interaction between REEs and soils, the nature of soils must be considered. In this paper, we discussed the distribution pattern of 232 Th and 238 U along with REEs in soil samples of weathered acid rock (granite and ryolite) collected from two prefectures of Japan: (1) Kobe city in Hyogo prefecture and (2) Mutsu city and Higashidori village in Aomori prefecture. (author)

Molybdenite Re-Os dating of Mo-Th-Nb-REE rich marbles: pre-Variscan processes in Moldanubian Variegated Group (Czech Republic

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Drábek Milan

2015-06-01

Full Text Available In an effort to contribute to the discussion concerning the age of rocks of the Moldanubian Variegated Group, we have undertaken Re-Os dating of molybdenite of banded carbonatite-like marbles (CLM from the graphite mine Václav at Bližná (Southern Bohemia, which belong to the metamorphic sequence of this group. The Re-Os model ages for the molybdenites range between 493 and 497 Ma and apparently correspond to the early stages of metamorphism connected with pre-Variscan rift-related tectono-metamorphic events, which affected and recrystallized sedimentary CLM material rich in Mo-Th-Nb-REE. The molybdenite bearing carbonatite like marbles situated in the footwall of Bližná graphite mine have been interpreted as carbonates with a large share of volcano-detritic material derived from contemporaneous primitive alkaline (carbonatite-like volcanism deposited in a shallow marine lagoonal environment. There is no geological evidence for the participation of fluids mobilized from host rocks in the formation of the CLM. Because the Re-Os chronometer in molybdenite is demonstrably stable through later Variscan facies metamorphism, the molybdenite chronometer has not been affected by subsequent thermal overprints associated with the Variscan orogeny.

Detection of rare-earth-mineral phases by scanning electron microscopy/energy dispersive x-rays (SEM/EDX) in the alkaline complexes of Tamil Nadu

International Nuclear Information System (INIS)

Sengupta, S.K.; Nathan, N.P.; Ganesan, V.; Shome, S.

2005-01-01

The alkaline complexes of the Southern Granulite Terrain (SGT) are generally restricted within NNW-SSE-trending Dharmapuri Shear Zone (DSZ), extending from Gudiyatham in the north and Bhavani in the south in Tamil Nadu. REE-rich phases have been studied under EDX (Energy Dispersive X-rays) from the different alkaline suites of Tamil Nadu. In Elagiri, the Th-rich epidote/allanite is concentrically zoned and occurs in the outermost coarse sub-solvus syenite, indicating that the REE concentration is restricted within the late-stage magmatic activity. In Koratti, the apatites are LREE rich. In Samalpatti Complex, the carbonatites host a number of REE-rich minerals commonly classified as betafite, along with nioborutite and nioboilmenite. The niobo-rutile and niobo-ilmenite show exsolved texture. The betafite is zoned with mendelyeerite. Some of the molybdenite in Samalpatti is dendritic indicating incomplete crystallisation. In Sivamalai, the REE phases are generally associated with ferrosyenite and nepheline syenite as adsorbed grains around apatite or carbonate. The REE minerals are Zr-REE titanate, REE-titano silicate and REE-yttrium silicate. In the Pikkili Complex, the REE minerals generally occur as rim around apatite and calcite. A discrete metamict allanite grain with radial cracks occurs within syenite. In Pakkanadu Complex zoned allanite occurs with distinct chemical zonation in syenite. Monazite and celesto-barite are associated with barite suggesting that the REE phases are developed in the late intrusive stage. (author)

Rare Earth Element Phases in Bauxite Residue

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Johannes Vind

2018-02-01

Full Text Available The purpose of present work was to provide mineralogical insight into the rare earth element (REE phases in bauxite residue to improve REE recovering technologies. Experimental work was performed by electron probe microanalysis with energy dispersive as well as wavelength dispersive spectroscopy and transmission electron microscopy. REEs are found as discrete mineral particles in bauxite residue. Their sizes range from <1 μm to about 40 μm. In bauxite residue, the most abundant REE bearing phases are light REE (LREE ferrotitanates that form a solid solution between the phases with major compositions (REE,Ca,Na(Ti,FeO3 and (Ca,Na(Ti,FeO3. These are secondary phases formed during the Bayer process by an in-situ transformation of the precursor bauxite LREE phases. Compared to natural systems, the indicated solid solution resembles loparite-perovskite series. LREE particles often have a calcium ferrotitanate shell surrounding them that probably hinders their solubility. Minor amount of LREE carbonate and phosphate minerals as well as manganese-associated LREE phases are also present in bauxite residue. Heavy REEs occur in the same form as in bauxites, namely as yttrium phosphates. These results show that the Bayer process has an impact on the initial REE mineralogy contained in bauxite. Bauxite residue as well as selected bauxites are potentially good sources of REEs.

Sources, behaviour, and environmental and human health risks of high-technology rare earth elements as emerging contaminants.

Science.gov (United States)

Gwenzi, Willis; Mangori, Lynda; Danha, Concilia; Chaukura, Nhamo; Dunjana, Nothando; Sanganyado, Edmond

2018-04-26

Recent studies show that high-technology rare earth elements (REEs) of anthropogenic origin occur in the environment including in aquatic systems, suggesting REEs are contaminants of emerging concern. However, compared to organic contaminants, there is a lack of comprehensive reviews on the anthropogenic sources, environmental behaviour, and public and ecological health risks of REEs. The current review aims to: (1) identify anthropogenic sources, transfer mechanisms, and environmental behaviour of REEs; (2) highlight the human and ecological health risks of REEs and propose mitigation measures; and (3) identify knowledge gaps and future research directions. Out of the 17 REEs, La, Gd, Ce and Eu are the most studied. The main sources of anthropogenic REE include; medical facilities, petroleum refining, mining and technology industries, fertilizers, livestock feeds, and electronic wastes and recycling plants. REEs are mobilized and transported in the environment by hydrological and wind-driven processes. Ecotoxicological effects include reduced plant growth, function and nutritional quality, genotoxicity and neurotoxicity in animals, trophic bioaccumulation, chronic and acute toxicities in soil organisms. Human exposure to REEs occurs via ingestion of contaminated water and food, inhalation, and direct intake during medical administration. REEs have been detected in human hair, nails, and biofluids. In humans, REEs cause nephrogenic systemic fibrosis and severe damage to nephrological systems associated with Gd-based contrast agents, dysfunctional neurological disorder, fibrotic tissue injury, oxidative stress, pneumoconiosis, cytotoxicity, anti-testicular effects, and male sterility. Barring REEs in medical devices, epidemiological evidence directly linking REEs in the environment to human health conditions remains weak. To minimize health risks, a conceptual framework and possible mitigation measures are highlighted. Future research is needed to better understand

Rare earth chemistry of gold-bearing sedimentary carbonate horizons from the Abitibi Greenstone Belt, Ontario, Canada

International Nuclear Information System (INIS)

Gibson, I.L.; Roberts, R.G.; Reading, D.J.R.

1984-01-01

The ankerite, gold ore bodies of the Dome Mine, Timmins, Ontario are interflow units, 1 to 3 m thick in a sequence of tholeiitic basalts. The units consist of discontinuous layers of ferroan dolomite, chert and pyroclastic material, and laminations of iron sulfides, tourmaline, and graphite. They have been interpreted as sediments on the basis of their internal structure. Seven Rare Earth elements (REE) (Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb) were determined by instrumental neutron activation analysis, on 10 samples of carbonate material from the ankerite units. The chondrite normalized REE plots have relatively flat patterns with, in some cases, positive Europium anomalies. The flat patterns suggest that the fluids from which the carbonate precipitated was in equilibrium with volcanic rocks of tholeiitic and komatiitic composition. The positive Europium anomalies imply that the fluids were reducing at times. Such patterns are characteristic of Archaean sediments and also the precipitates associated with the discharge of hydrothermal solutions from vents on the East Pacific Rise

Fusion Bead Procedure for Nuclear Forensics Employing Synthetic Enstatite to Dissolve Uraniferous and Other Challenging Materials Prior to Laser Ablation Inductively Coupled Plasma Mass Spectrometry.

Science.gov (United States)

Reading, David G; Croudace, Ian W; Warwick, Phillip E

2017-06-06

There is an increasing demand for rapid and effective analytical tools to support nuclear forensic investigations of seized or suspect materials. Some methods are simply adapted from other scientific disciplines and can effectively be used to rapidly prepare complex materials for subsequent analysis. A novel sample fusion method is developed, tested, and validated to produce homogeneous, flux-free glass beads of geochemical reference materials (GRMs), uranium ores, and uranium ore concentrates (UOC) prior to the analysis of 14 rare earth elements (REE) via laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The novelty of the procedure is the production of glass beads using 9 parts high purity synthetic enstatite (MgSiO 3 ) as the glass former with 1 part of sample (sample mass ∼1.5 mg). The beads are rapidly prepared (∼10 min overall time) by fusing the blended mixture on an iridium strip resistance heater in an argon-purged chamber. Many elements can be measured in the glass bead, but the rare earth group in particular is a valuable series in nuclear forensic studies and is well-determined using LA-ICP-MS. The REE data obtained from the GRMs, presented as chondrite normalized patterns, are in very good agreement with consensus patterns. The UOCs have comparable patterns to solution ICP-MS methods and published data. The attractions of the current development are its conservation of sample, speed of preparation, and suitability for microbeam analysis, all of which are favorable for nuclear forensics practitioners and geochemists requiring REE patterns from scarce or valuable samples.

Extraction of rare earth elements from low-grade Bauxite via precipitation reaction

Science.gov (United States)

Kusrini, E.; Nurani, Y.; Bahari, ZJ

2018-03-01

The aim of this research was to determine the optimum hydrometallurgical parameters to extract the rare earth elements (REE) from low-grade bauxite through acid leaching and precipitation reaction. REE or lanthanide recovery by a precipitation method with sodium sulphate and sodium phosphate as precipitation agents is reported where the effect of pH and recovery of REE are described. The metal composition of REE in low-grade bauxite after treatment were analyzed by ICP-OES. The total recovery values of REE elements at the first precipitation reaction using sodium sulphate as the precipitation agent at pH 3.5 showed ~68.2% of lanthanum, ~18.9% cerium, and ~7.8% yttrium. Lanthanum was the rare-earth element present at the highest concentration in the low-grade bauxite after the series treatments. An optimum pH of 3.5 for precipitation of rare-earth elements using sodium sulphate was demonstrated where this method is recommended for the extraction of REE elements from low-grade bauxite.

Giant cell tumor with secondary aneurysmal bone cyst shows heterogeneous metabolic pattern on {sup 18}F-FDG PET.CT: A case reort

Energy Technology Data Exchange (ETDEWEB)

Park, Hee Jeong; Kwon, Seong Young; Yoon, Yeon Hong [Chonnam National University Hwasun Hospital, Huasun (Korea, Republic of); Cho, Sang Geon; Kim, Jahae; Song, Ho Chun; Kim, Sung Sun; Park, Jin Gyoon [Chonnam National University Hospital, Gwangju (Korea, Republic of)

2016-12-15

Giant cell tumor (GCT) is a generally benign bone tumor accounting for approximately 5 % of all primary bone neoplasms. Cystic components in GCTs that indicate secondary aneurysmal bone cysts (ABCs) are reported in 14 % of GCTs. Although both of them have been described separately in previous reports that may show considerable fluorodeoxyglucose (FDG) uptake despite their benign nature, the findings of GCT with secondary ABC on 18F-FDG positron emission tomography/computed tomography (PET/CT) have not been well-known. We report a case of GCT with secondary ABC in a 26-year-old woman. 18F-FDG PET/CT revealed a heterogeneous hypermetabolic lesion in the left proximal femur with the maximum standardized uptake value of 4.7. The solid components of the tumor showed higher FDG uptake than the cystic components. These observations suggest that the ABC components in GCTs show heterogeneous metabolic patterns on {sup 18}F-FDG PET/CT.

Giant cell tumor with secondary aneurysmal bone cyst shows heterogeneous metabolic pattern on "1"8F-FDG PET.CT: A case reort

International Nuclear Information System (INIS)

Park, Hee Jeong; Kwon, Seong Young; Yoon, Yeon Hong; Cho, Sang Geon; Kim, Jahae; Song, Ho Chun; Kim, Sung Sun; Park, Jin Gyoon

2016-01-01

Giant cell tumor (GCT) is a generally benign bone tumor accounting for approximately 5 % of all primary bone neoplasms. Cystic components in GCTs that indicate secondary aneurysmal bone cysts (ABCs) are reported in 14 % of GCTs. Although both of them have been described separately in previous reports that may show considerable fluorodeoxyglucose (FDG) uptake despite their benign nature, the findings of GCT with secondary ABC on 18F-FDG positron emission tomography/computed tomography (PET/CT) have not been well-known. We report a case of GCT with secondary ABC in a 26-year-old woman. 18F-FDG PET/CT revealed a heterogeneous hypermetabolic lesion in the left proximal femur with the maximum standardized uptake value of 4.7. The solid components of the tumor showed higher FDG uptake than the cystic components. These observations suggest that the ABC components in GCTs show heterogeneous metabolic patterns on "1"8F-FDG PET/CT

Technospheric Mining of Rare Earth Elements from Bauxite Residue (Red Mud): Process Optimization, Kinetic Investigation, and Microwave Pretreatment.

Science.gov (United States)

Reid, Sable; Tam, Jason; Yang, Mingfan; Azimi, Gisele

2017-11-10

Some rare earth elements (REEs) are classified under critical materials, i.e., essential in use and subject to supply risk, due to their increasing demand, monopolistic supply, and environmentally unsustainable and expensive mining practices. To tackle the REE supply challenge, new initiatives have been started focusing on their extraction from alternative secondary resources. This study puts the emphasis on technospheric mining of REEs from bauxite residue (red mud) produced by the aluminum industry. Characterization results showed the bauxite residue sample contains about 0.03 wt% REEs. Systematic leaching experiments showed that concentrated HNO 3 is the most effective lixiviant. However, because of the process complexities, H 2 SO 4 was selected as the lixiviant. To further enhance the leaching efficiency, a novel process based on microwave pretreatment was employed. Results indicated that microwave pretreatment creates cracks and pores in the particles, enabling the lixiviant to diffuse further into the particles, bringing more REEs into solution, yielding of 64.2% and 78.7% for Sc and Nd, respectively, which are higher than the maximum obtained when HNO 3 was used. This novel process of "H 2 SO 4 leaching-coupled with-microwave pretreatment" proves to be a promising technique that can help realize the technological potential of REE recovery from secondary resources, particularly bauxite residue.

Application of the Instrumental Neutron Activation Analysis and High Performance Liquid Chromatography (HPLC) in the rare earth elements determination in reference geological materials

International Nuclear Information System (INIS)

Figueiredo, Ana M.G.; Moraes, Noemia M.P. de; Shihomatsu, Helena M.

1997-01-01

Instrumental Neutron Activation Analysis (INAA) and High Performance Liquid Chromatography (HPLC) were applied to the determination of rare earth elements (REE) in the geological reference materials AGV-1, G-2 and GSP-1 (USGS). Results obtained by both techniques showed good agreement with certified values, giving relative errors less than 10%. The La, Ce, Nd, Sm, Eu, Tb, Yb and Lu REE elements were determined. All the REE except Dy and Y were determined by HPLC. The reference material G94, employed in the International Proficiency Test for Analytical Geochemistry Laboratories (GeoTP1) was analysed. The results obtained are a contribution to REE contents in this sample. The INAA and HPLC application to the determination of REE in this kind of matrix is also discussed. (author). 10 refs., 1 fig., 5 tabs

Petrogenesis of Alta'ameem meteorite (Iraq) inferred from major, trace, REE and PGE+Au content

Science.gov (United States)

Kettanah, Yawooz A.; Ismail, Sabah A.

2018-03-01

Alta'ameem Meteorite (AM) is an unaltered ordinary LL chondrite that hit an area near Kirkuk City in northern Iraq on 1977. It has an ash-gray colour with a thin black fusion crust, and consists of spheroidal chondrules and variously shaped clasts aggregated together by a fine grained matrix. The chondrules of Alta'ameem Meteorite include all known types in similar meteorites elsewhere. Mineralogically, the AM consists of silicates (olivine - Fa27.7; pyroxene - Fs23.2 (Opx) and 20.5 (Cpx); plagioclase - Ab73.5An22.1Or4.7), alloys and metals (taenite, tetrataenite, kamacite, and native copper), oxides (ilmenite and chromite), sulfides (troilite), and phosphates (apatite) as well as few unidentified minerals including a Fe-Ti-Cr oxide and Fe-Ni sulfide. The chemistry of AM is dominated by SiO2, MgO, and FeOt accounting for >91 wt% of the bulk composition with minor amounts of Al2O3, CaO, Na2O, S, Ni and Cr. It contains 3675 ppb REE which is within the range of most chondrites, with a negative (-0.8) Sm- and positive (+1.2) Tb-anomalies and a near flat normalized trend (LaN/YbN = 1.16). The concentration of PGEs and Au, Ni, Co, and Cr is low in comparison to most chondrites. The K/La, Ru/Rh vs. Pt/Pd, and Pd/Ir ratio (1.85), and low PGE indicates that the AM is somewhat distinct from other meteorites. The AM has W0 weathering grade and very weak (S2) shock metamorphism. Although the AM has some petrographical and geochemical differences with other chondrites, it still can be considered as LL5 chondrite.

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

Science.gov (United States)

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

2014-11-01

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

Resting energy expenditure prediction in recreational athletes of 18-35 years: confirmation of Cunningham equation and an improved weight-based alternative.

Science.gov (United States)

ten Haaf, Twan; Weijs, Peter J M

2014-01-01

Resting energy expenditure (REE) is expected to be higher in athletes because of their relatively high fat free mass (FFM). Therefore, REE predictive equation for recreational athletes may be required. The aim of this study was to validate existing REE predictive equations and to develop a new recreational athlete specific equation. 90 (53 M, 37 F) adult athletes, exercising on average 9.1 ± 5.0 hours a week and 5.0 ± 1.8 times a week, were included. REE was measured using indirect calorimetry (Vmax Encore n29), FFM and FM were measured using air displacement plethysmography. Multiple linear regression analysis was used to develop a new FFM-based and weight-based REE predictive equation. The percentage accurate predictions (within 10% of measured REE), percentage bias, root mean square error and limits of agreement were calculated. Results: The Cunningham equation and the new weight-based equation REE(kJ / d) = 49.940* weight(kg) + 2459.053* height(m) - 34.014* age(y) + 799.257* sex(M = 1,F = 0) + 122.502 and the new FFM-based equation REE(kJ / d) = 95.272*FFM(kg) + 2026.161 performed equally well. De Lorenzo's equation predicted REE less accurate, but better than the other generally used REE predictive equations. Harris-Benedict, WHO, Schofield, Mifflin and Owen all showed less than 50% accuracy. For a population of (Dutch) recreational athletes, the REE can accurately be predicted with the existing Cunningham equation. Since body composition measurement is not always possible, and other generally used equations fail, the new weight-based equation is advised for use in sports nutrition.

Association of Sub-continental and Asthenosphere related Volcanism in NW Iran,Implication forMantle thermal perturbation induced by slab break off and collision event

Science.gov (United States)

Jahangiri, A.

2017-12-01

Cenozoic magmatic rocks occur extensively in the north of the Zagros suture zone and constitute a significant component of the continental crust in this segment of the Alpine-Himalayan orogenic belt. They range in age from Eocene to quaternary. Miocene to Plio-Quaternary volcanism with post-collisional related significant is covered vast areas in NW Iran. These volcanic rocks can be divided into three different sub-groups on the basis of their mineralogy, geochemistry and magma sources including: 1. alkaline leucite-bearing mafic rocks, which are characterized with high ratios of K2O/Na2O, high content LILE and low HFS elements like Ti, Nb and Ta. They are display fractionated REE patterns and based on different discrimination diagrams show similarity with subduction related magmas. 2- Olivine basalt to trachy-basaltic samples which shows similarity to within plate basalts with high content of TiO2, Nb, Ta and fractionated REE pattern. However, compared with a global average of OIB, they are display slightly higher LIL elements and lower HFS elements concentrations, features that resemble to the arc magmas and suggest that the source of the magmas may have been contaminated by slab-derived fluids. These rocks have simple mineralogical composition with plagioclase, clinopyroxene and olivine. 3- Dominant dacitic volcanic rocks with adakitic geochemical characteristics such as highly fractionate REE pattern and high Sr/Y ratio. Generation of adakitic magmas can be related to increased temperatures in the subduction zone due to mantle upwelling and slab tearing. Subsequent asthenospheric upwelling could be caused direct melting of sub-continental mantle to produce the alkaline magmas, with high contents of K2O, MgO and volatile rich phase's potassic magmas that led to crystallization of leucite, phlogopite, apatite and olivine in studied samples. Rupture of the continental lithosphere by strike-slip-related transtensional deformation might have caused decompression

Origins of mass-dependent and mass-independent Ca isotope variations in meteoritic components and meteorites

Science.gov (United States)

Bermingham, K. R.; Gussone, N.; Mezger, K.; Krause, J.

2018-04-01

The Ca isotope composition of meteorites and their components may vary due to mass-dependent and/or -independent isotope effects. In order to evaluate the origin of these effects, five amoeboid olivine aggregates (AOAs), three calcium aluminum inclusions (CAIs), five chondrules (C), a dark inclusion from Allende (CV3), two dark fragments from North West Africa 753 (NWA 753; R3.9), and a whole rock sample of Orgueil (CI1) were analyzed. This is the first coupled mass-dependent and -independent Ca isotope dataset to include AOAs, a dark inclusion, and dark fragments. Where sample masses permit, Ca isotope data are reported with corresponding petrographic analyses and rare earth element (REE) relative abundance patterns. The CAIs and AOAs are enriched in light Ca isotopes (δ44/40Ca -5.32 to +0.72, where δ44/40Ca is reported relative to SRM 915a). Samples CAI 5 and AOA 1 have anomalous Group II REE patterns. These REE and δ44/40Ca data suggest that the CAI 5 and AOA 1 compositions were set via kinetic isotope fractionation during condensation and evaporation. The remaining samples show mass-dependent Ca isotope variations which cluster between δ44/40Ca +0.53 and +1.59, some of which are coupled with unfractionated REE abundance patterns. These meteoritic components likely formed through the coaccretion of the evaporative residue and condensate following Group II CAI formation or their chemical and isotopic signatures were decoupled (e.g., via nebular or parent-body alteration). The whole rock sample of Orgueil has a δ44/40Ca +0.67 ± 0.18 which is in agreement with most published data. Parent-body alteration, terrestrial alteration, and variable sampling of Ca-rich meteoritic components can have an effect on δ44/40Ca compositions in whole rock meteorites. Samples AOA 1, CAI 5, C 2, and C 4 display mass-independent 48/44Ca anomalies (ε48/44Ca +6 to +12) which are resolved from the standard composition. Other samples measured for these effects (AOA 5, CAI 1, CAI 2

Chemical and oxygen isotopic properties of ordinary chondrites (H5, L6) from Oman: Signs of isotopic equilibrium during thermal metamorphism

Science.gov (United States)

Ali, Arshad; Nasir, Sobhi J.; Jabeen, Iffat; Al Rawas, Ahmed; Banerjee, Neil R.; Osinski, Gordon R.

2017-10-01

Mean bulk chemical data of recently found H5 and L6 ordinary chondrites from the deserts of Oman generally reflect isochemical features which are consistent with the progressive thermal metamorphism of a common, unequilibrated starting material. Relative differences in abundances range from 0.5-10% in REE (Eu = 14%), 6-13% in siderophile elements (Co = 48%), and >10% in lithophile elements (exceptions are Ba, Sr, Zr, Hf, U = >30%) between H5 and L6 groups. These differences may have accounted for variable temperature conditions during metamorphism on their parent bodies. The CI/Mg-normalized mean abundances of refractory lithophile elements (Al, Ca, Sm, Yb, Lu, V) show no resolvable differences between H5 and L6 suggesting that both groups have experienced the same fractionation. The REE diagram shows subtle enrichment in LREE with a flat HREE pattern. Furthermore, overall mean REE abundances are 0.6 × CI with enriched La abundance ( 0.9 × CI) in both groups. Precise oxygen isotope compositions demonstrate the attainment of isotopic equilibrium by progressive thermal metamorphism following a mass-dependent isotope fractionation trend. Both groups show a slope-1/2 line on a three-isotope plot with subtle negative deviation in Δ17O associated with δ18O enrichment relative to δ17O. These deviations are interpreted as the result of liberation of water from phyllosilicates and evaporation of a fraction of the water during thermal metamorphism. The resultant isotope fractionations caused by the water loss are analogous to those occurring between silicate melt and gas phase during CAI and chondrule formation in chondrites and are controlled by cooling rates and exchange efficiency.

Trends in the Rare Earth Element Content of U.S.-Based Coal Combustion Fly Ashes.

Science.gov (United States)

Taggart, Ross K; Hower, James C; Dwyer, Gary S; Hsu-Kim, Heileen

2016-06-07

Rare earth elements (REEs) are critical and strategic materials in the defense, energy, electronics, and automotive industries. The reclamation of REEs from coal combustion fly ash has been proposed as a way to supplement REE mining. However, the typical REE contents in coal fly ash, particularly in the United States, have not been comprehensively documented or compared among the major types of coal feedstocks that determine fly ash composition. The objective of this study was to characterize a broad selection of U.S. fly ashes of varied geological origin in order to rank their potential for REE recovery. The total and nitric acid-extractable REE content for more than 100 ash samples were correlated with characteristics such as the major element content and coal basin to elucidate trends in REE enrichment. Average total REE content (defined as the sum of the lanthanides, yttrium, and scandium) for ashes derived from Appalachian sources was 591 mg kg(-1) and significantly greater than in ashes from Illinois and Powder River basin coals (403 and 337 mg kg(-1), respectively). The fraction of critical REEs (Nd, Eu, Tb, Dy, Y, and Er) in the fly ashes was 34-38% of the total and considerably higher than in conventional ores (typically less than 15%). Powder River Basin ashes had the highest extractable REE content, with 70% of the total REE recovered by heated nitric acid digestion. This is likely due to the higher calcium content of Powder River Basin ashes, which enhances their solubility in nitric acid. Sc, Nd, and Dy were the major contributors to the total REE value in fly ash, based on their contents and recent market prices. Overall, this study shows that coal fly ash production could provide a substantial domestic supply of REEs, but the feasibility of recovery depends on the development of extraction technologies that could be tailored to the major mineral content and origins of the feed coal for the ash.

87Sr/86Sr and 143Nd/144Nd for disentangling anthropogenic and natural REE contributions in river water during flood events.

Science.gov (United States)

Hissler, Christophe; Stille, Peter; Pfister, Laurent

2017-04-01

The sustainable management of water resources is one of the greatest challenges of the 21st century. Water is a vital resource that is increasingly put under pressure from multiple perspectives. While the global population is on the rise, socio-economic development makes equally rapid progress - eventually compromising access to clean water bodies. Multiple pollution sources constitute an immediate threat to aquatic ecosystems and are likely to cause long lasting contaminations of water bodies that are critical for drinking and/or irrigation water production. There is a pressing need for an adequate quantification of anthropogenic impacts on the critical zone of river basins and the identification of the temporal dynamics of these impacts. As an example, despite the work done to assess the environmental impact of REE pollutions in larger river systems, we are still lacking information on the dynamics of these anthropogenic compounds in relation to rapid hydrological changes. Filling these knowledge gaps is a pre-requisite for the design and implementation of sustainable water resources management strategies. In order to better constrain the relative contributions of both anthropogenic and geogenic trace element sources we propose using a multitracer approach combining elemental and 87Sr/86Sr, 143Nd/144Nd, and 206Pb/207Pb isotopic ratios. The use of these three separate isotopic systems together with REE concentrations is new in the field of anthropogenic source identification in river systems. We observed enrichments in Anthropogenic Rare Earth Elements (AREE) for dissolved Gd and suspended Nd loads of river water. With increasing discharge, AREE anomalies progressively disappeared and gave way to the geogenic chemical signature of the basin in both dissolved and suspended loads. The isotopic data confirm these observations and shed new light on the trace elements sources. On the one hand, dissolved loads have peculiar isotopic characteristics and carry mainly

Rare Earth Element Fluorocarbonate Minerals from the Olympic Dam Cu-U-Au-Ag Deposit, South Australia

Directory of Open Access Journals (Sweden)

Danielle S. Schmandt

2017-10-01

äsite and synchysite may have formed earlier, coincident with hydrothermal alteration of granite releasing Ca from feldspars. Other categories of bastnäsite, notably those co-existing with sulfides, and reaching the top of the IOCG mineralization at Olympic Dam (chalcocite + bornite zone are relatively younger. Such an interpretation is concordant with subtle changes in the REE patterns for the different categories. The common association of bastnäsite and fluorite throughout the deposit is typical of the hematite breccias and can be deposited from neutral, slightly acidic fluids (sericite stability at T ≈ 300 °C.

High Iridium concentration of alkaline rocks of Deccan and ...

Indian Academy of Sciences (India)

R. Narasimhan, Krishtel eMaging Solutions

and nine rare-earth elements (REE: La, Ce, Nd ... Rare earth patterns of different samples of car- bonatite ..... Ray J S 1997 Stable and radioisotopic constraints on the evolution of ... volcanism pre-date the Cretaceous/Tertiary transition?; Earth ...

Petrological mineralogical and geochemical characterization of the granitoids and fracture fillings developed in Ratones Mines (Spain)

International Nuclear Information System (INIS)

Buil Gutierrez, B.

2002-01-01

The petrological, mineralogical and geochemical characterisation of the granitoids and fracture fillings developed in the Ratones Mine (Caceres, Spain) has been done in order to understand rock-water interaction processes which control water geochemical parameters. Special interest has been devoted to the analysis and interpretation of REE patterns in the solid phase (granitoids and fracture fillings) because they constitute geochemical tracers in water-rock interaction process. Moreover, REE are considered as actinide analogues. In order to characterise the solid phase (granitoids and fracture fillings) several investigation scales (system, outcrop, whole rock, mineral and geochemical components) have been considered and different types of samples have been analysed. These factors control the methodological approach used in this investigation. The analytical methods we have used in this investigation are microscope, qualitative and semi-quantitative methods (XRD, SEM,EDAX) and quantitative methods (ICP-MS, XRF, EM, LAM-IC-MS). The bulk of the granitoids located around the Ratones Mine Belongs to the alkaline feldspar granite-sienogranite lihotype and they show a peraluminous and subalkaline pattern. From the mineralogical point of view, they are composed by quartz, K-feldspar (Or>90%), showing sericitation, moscovitization and turmolinization altherations, alkaline plagioclase (An-=-3%), usually altered to sericite, saussirite and less frequently affected by moscovitization processes, Fe-Al biotite, frequently affected by chloritization processes and sometimes replaced by muscovite, and finally muscovite (>2% celadonite and <4% paragonite) both of primary and secondary origin. The differences observed between the different lithotypes are related with the modal proportion of the principal minerals,with the presence or absence of certain accessory minerals ( turmaline, cordierite), with specific textural patterns, grain size and also with the richness in specific

Effects of soil type on leaching and runoff transport of rare earth elements and phosphorous in laboratory experiments.

Science.gov (United States)

Wang, Lingqing; Liang, Tao; Chong, Zhongyi; Zhang, Chaosheng

2011-01-01

Through leaching experiments and simulated rainfall experiments, characteristics of vertical leaching of exogenous rare earth elements (REEs) and phosphorus (P) and their losses with surface runoff during simulated rainfall in different types of soils (terra nera soil, cinnamon soil, red soil, loess soil, and purple soil) were investigated. Results of the leaching experiments showed that vertical transports of REEs and P were relatively low, with transport depths less than 6 cm. The vertical leaching rates of REEs and P in the different soils followed the order of purple soil > terra nera soil > red soil > cinnamon soil > loess soil. Results of the simulated rainfall experiments (83 mm h⁻¹) revealed that more than 92% of REEs and P transported with soil particles in runoff. The loss rates of REEs and P in surface runoff in the different soil types were in the order of loess soil > terra nera soil > cinnamon soil > red soil > purple soil. The total amounts of losses of REEs and P in runoff were significantly correlated.

Geochemistry, mineralization and age of tin-bearing ganites from Pitinga, nortwestern Brazil

International Nuclear Information System (INIS)

Macambira, M.J.B.; Teixeira, J.T.; Daoud, W.E.K.; Costi, H.T.

1987-01-01

One of the important geological units of the Central Amazonian Provinceis formed by anarogenic granit plutons, some of them associated with important ore deposits. The larget ore deposits of SN,Zr,Nb,Ta, and REE in this Province are associeted with the madeira (MD) and Agua Boa (AB) plutons, Pitinga region, NW Brazil. These plutons crosscut the volcanic rocks from Iricoume Group and sediments from Urupi formation, and follow the regional trend, suggesting magma ascension along deep faults. These plutons are composed by three granitic units, which are, in order of emplacement: granite with rapakivi tendency; fine-grained porphyritic granite; and biotite granite. There are metasomatic variations to greisen (in AB pluton) and apogranite (in MD pluton) associated genetically with ore deposits. Major and trace elements contents shown sub-alkalic to peraluminous characteristics, with an increasing of SiO 2 , F,Sn,Rb, and Y, and a decreasing of Al 2 O 3 , FeO,Fe 2 O 3 ,CaO,MgO,TiO 2 ,Sr,Zr and Nb toward the biotite granite. As a whole, AB pluton has the lowest Nb contents, while the MD pluton has the lowest Y and REE contents. The REE patterns of AB and MD are similar, showing high absolute contents, pronounced negative Eu anomalies, and a little fractionated patterns. The apogranite is depleted in LREE by albitization process. Rb-Sr whole-rock isochron constructed with nine samples from AB and MD plutons indicates an age of 1,691 +- 34 Ma with initial ratio of 0.7062 +- 0.0067. The geological and geochemical features of AB and MD plutons are similar with cratogenic bodies originated in tensional regions, as A-type granites. However, the classifications of these plutons in separated regional suites is not well established due to absence of more strong criteria to do so, up to now. (author) [pt

Watson: A new link in the IIE iron chain

Science.gov (United States)

Olsen, Edward; Davis, Andrew; Clarke, Roy S., Jr.; Schultz, Ludolf; Weber, Hartwig W.; Clayton, Robert; Mayeda, Toshiko; Jarosewich, Eugene; Sylvester, Paul; Grossman, Lawrence

1994-01-01

Watson, which was found in 1972 in South Australia, contains the largest single silicate rock mass seen in any known iron meteorite. A comprehensive study has been completed on this unusual meteorite: petrography, metallography, analyses of the silicate inclusion (whole rock chemical analysis, INAA, RNAA, noble gases, and oxygen isotope analysis) and mineral compositions (by electron microprobe and ion microprobe). The whole rock has a composition of an H-chondrite minus the normal H-group metal and troilite content. The oxygen isotope composition is that of the silicates in the IIE iron meteorites and lies along an oxygen isotope fractionation line with the H-group chondrites. Trace elements in the metal confirm Watson is a new IIE iron. Whole rock Watson silicate shows an enrichment in K and P (each approximately 2X H-chondrites). The silicate inclusion has a highly equilibrated igneous (peridotite-like) texture with olivine largely poikilitic within low-Ca pyroxene: olivine (Fa20), opx (Fs17Wo3), capx (Fs9Wo14)(with very fine exsolution lamellae), antiperthite feldspar (An1-3Or5) with less than 1 micron exsolution lamellae (An1-3Or greater than 40), shocked feldspar with altered stoichiometry, minor whitlockite (also a poorly characterized interstitial phosphate-rich phase) and chromite, and only traces of metal and troilite. The individual silicate minerals have normal chondritic REE patterns, but whitlockite has a remarkable REE pattern. It is very enriched in light REE (La is 720X C1, and Lu is 90X C1, as opposed to usual chonditic values of approximately 300X and 100-150X, respectively) with a negative Eu anomaly. The enrichment of whole rock K is expressed both in an unusually high mean modal Or content of the feldspar, Or13, and in the presence of antiperthite.

Importance of nanoparticles and colloids from volcanic ash for riverine transport of trace elements to the ocean: evidence from glacial-fed rivers after the 2010 eruption of Eyjafjallajökull Volcano, Iceland.

Science.gov (United States)

Tepe, Nathalie; Bau, Michael

2014-08-01

Volcanic ashes are often referenced as examples for natural nanoparticles, yet the particle size distribution eruptions at Eyjafjallajökull in 2010. In addition to the dissolved concentrations of rare earth elements (REE), Zr, Hf, Nb, and Th in the 450 nm-filtered waters, we also studied the respective filter residues (river particulates >450 nm) and volcanic ash. In spite of the low solubilities and high particle-reactivities of the elements studied, most water samples show high dissolved concentrations, such as up to 971 ng/kg of Ce and 501 ng/kg of Zr. Except for the pure glacial meltwater and glacial base flow, all waters display the same shale-normalized REE patterns with pronounced light and heavy REE depletion and positive Eu anomalies. While such patterns are unusual for river waters, they are similar to those of the respective river particulates and the volcanic ash, though at different concentration levels. The distribution of dissolved Zr, Hf, Nb, and Th in the waters also matches that of filter residues and ash. This strongly suggests that in all 450 nm-filtered river waters, the elements studied are associated with solid ash particles smaller than 450 nm. This reveals that volcanic ash-derived nanoparticles and colloids are present in these glacial-fed rivers and that such ultrafine particles control the trace element distribution in the surface runoff. Subsequent to explosive volcanic eruptions, these waters provide terrigenous input from landmasses to estuaries, that is characterized by a unique trace element signature and that subsequent to modification by estuarine processes delivers a pulse of nutrients to coastal seawater in regions not affected by plume fall-out. Copyright © 2014 Elsevier B.V. All rights reserved.

Leaching of rare earth elements from fluorescent powder using the tea fungus Kombucha.

Science.gov (United States)

Hopfe, Stefanie; Flemming, Katrin; Lehmann, Falk; Möckel, Robert; Kutschke, Sabine; Pollmann, Katrin

2017-04-01

In most modern technologies such as flat screens, highly effective magnets and lasers, as well as luminescence phosphors, Rare Earth Elements (REE) are used. Unfortunately no environmentally friendly recycling process exists so far. In comparison to other elements the interaction of microorganisms with REE has been studied to a less extent. However, as REE are ubiquitously present in nature it can be assumed that microorganisms play an important role in the biogeochemistry of REE. This study investigates the potential of organic acid-producing microbes for extracting REE from industrial waste. In Germany, 175 tons of fluorescent phosphor (FP) are collected per year as a distinct fraction from the recycling of compact fluorescent lamps. Because the FP contains about 10% of REE-oxides bound in the so-called triband dyes it is a readily accessible secondary resource of REE. Using the symbiotic mixed culture Kombucha, consisting of yeasts and acetic acid bacteria, REE were leached at a significant rate. The highest leaching-rates were observed in shake cultures using the entire Kombucha-consortium or its supernatant as leaching agent compared to experiments using the isolates Zygosaccharomyces lentus and Komagataeibacter hansenii as leaching organisms. During the cultivation, the pH decreased as a result of organic acid production (mainly acetic and gluconic acid). Thus, the underlying mechanism of the triband dye solubilisation is probably linked to the carboxyl-functionality or a proton excess. In accordance with the higher solubility of REE-oxides compared to REE-phosphates and -aluminates, the red dye Y 2 O 3 :Eu 2+ containing relatively expensive REE was shown to be preferentially solubilized. These results show that it is possible to dissolve the REE-compounds of FP with the help of microbial processes. Moreover, they provide the basis for the development of an eco-friendly alternative to the currently applied methods that use strong inorganic acids or toxic

Study of the oxides nature effect of rare and rare earth elements on the aluminium-chromium catalyst properties

International Nuclear Information System (INIS)

Dadashev, B.A.; Abbasov, S.G.; Sarydzhanov, A.A.; AN Azerbajdzhanskoj SSR, Baku. Inst. Neftekhimicheskikh Protsessov)

1975-01-01

Adsorption studies have shown that oxides of rare and rare earth elements REE appreciably influence the structure of aluminium-chrome catalyst. Alkaline promotors, unlike REE, contribute to the formation of developed contact surface. Electrophysical investigations show that oxides of rare elements introduced into the catalyst increase its conductivity and activation energy. As for REE oxides, they decrease the conductivity and increase the activation energy. Catalysts with developed surface and high conductivity are also more active in the reaction of isopentane dehydration

Determination of rare earth elements in biomonitors by neutron activation; Determinacao de elementos terras raras em biomonitores por ativacao neutronica

Energy Technology Data Exchange (ETDEWEB)

Figueiredo, Ana M.G.; Saiki, Mitiko; Ticianelli, R.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Domingos, M.; Alves, E.S.; Marcelli, M.P. [Instituto de Botanica, Sao Paulo, SP (Brazil)

2000-07-01

The rare earth elements (REE) are becoming more and more important from the technological point of view, due to their increasing use in modern industry. Due to this fact, environmental contamination by REE may become significant, and little information are still available about biological effects of REE in plants, animals and human beings. The use of biomonitors to control environmental pollution has been an ecological and economical alternative in Europe and United Sates, to minimize the high costs of conventional equipment s. In the present paper, neutron activation analysis was employed to determine La, Ce, Nd, Sm, Eu, Tb, Yb and Lu in the lichen Canoparmelia texana and in Tillandsia usneoides, species that have been widely used as monitors of atmospheric pollution. The results showed an accumulation of REE in the biomonitors, indicating good possibilities of their utilization in the study of environmental contamination by REE. (author)

Determination of rare earth elements in biomonitors by neutron activation

International Nuclear Information System (INIS)

Figueiredo, Ana M.G.; Saiki, Mitiko; Ticianelli, R.B.; Domingos, M.; Alves, E.S.; Marcelli, M.P.

2000-01-01

The rare earth elements (REE) are becoming more and more important from the technological point of view, due to their increasing use in modern industry. Due to this fact, environmental contamination by REE may become significant, and little information are still available about biological effects of REE in plants, animals and human beings. The use of biomonitors to control environmental pollution has been an ecological and economical alternative in Europe and United Sates, to minimize the high costs of conventional equipment s. In the present paper, neutron activation analysis was employed to determine La, Ce, Nd, Sm, Eu, Tb, Yb and Lu in the lichen Canoparmelia texana and in Tillandsia usneoides, species that have been widely used as monitors of atmospheric pollution. The results showed an accumulation of REE in the biomonitors, indicating good possibilities of their utilization in the study of environmental contamination by REE. (author)

REE distributions in a high-grade Archaean gneiss complex in Scotland: Implications for the genesis of ancient sialic crust

International Nuclear Information System (INIS)

Drury, S.A.

1978-01-01

Seventeen rocks from the Lewisian Gneiss of the Inner Hebrides of Scotland, which represent three distinct lithological types at granulite to greenschist facies of metamorphism show rare-earth element patterns which seem not to have been disturbed by their complex metamorphic history. Some indication of their origin can be obtained by simple geochemical models. (Auth.)

Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration

Science.gov (United States)

Tan, Quanyin; Deng, Chao; Li, Jinhui

2016-01-01

With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency.

Tracking the Depleted Mantle Signature in Melt Inclusions and Residual Glass of Basaltic Martian Shergottites using Secondary Ionization Mass Spectrometry

Science.gov (United States)

Peters, Timothy J.; Simon, Justin I.; Jones, John H.; Usui, Tomohiro; Economos, Rita C.; Schmitt, Axel K.; McKeegan, Kevin D.

2013-01-01

Trace element abundances of depleted shergottite magmas recorded by olivine-hosted melt inclusions (MI) and interstitial mesostasis glass were measured using the Cameca ims-1270 ion microprobe. Two meteorites: Tissint, an olivine-­phyric basaltic shergottite which fell over Morocco July 18th 2001; and the Antarctic meteorite Yamato 980459 (Y98), an olivine-phyric basaltic shergottite with abundant glassy mesostasis have been studied. Chondrite-­normalized REE patterns for MI in Tissint and Y98 are characteristically LREE depleted and, within analytical uncertainty, parallel those of their respective whole rock composition; supporting each meteorite to represent a melt composition that has experienced closed-­system crystallization. REE profiles for mesostasis glass in Y98 lie about an order of magnitude higher than those from the MI; with REE profiles for Tissint MI falling in between. Y98 MI have the highest average Sm/Nd and Y/Ce ratios, reflecting their LREE depletion and further supporting Y98 as one of our best samples to probe the depleted shergotitte mantle. In general, Zr/Nb ratios overlap between Y98 and Tissint MI, Ce/Nb ratios overlap between Y98 MI and mesostasis glass, and Sm/Nd ratios overlap between Y98 mesostasis glass and Tissint MI. These features support similar sources for both, but with subtle geochemical differences that may reflect different melting conditions or fractionation paths during ascent from the mantle. Interestingly, the REE patterns for both Y98 bulk and MI analyses display a flattening of the LREE that suggests a crustal contribution to the Y98 parent melt. This observation has important implications for the origins of depleted and enriched shergottites.

Rare earth elements, yttrium and H, O, C, Sr, Nd and Pb isotope studies in mineral waters and corresponding rocks from NW-Bohemia, Czech Republic

International Nuclear Information System (INIS)

Moeller, P.; Dulski, P.; Gerstenberger, H.; Morteani, G.; Fuganti, A.

1998-01-01

The sparkling waters from the area of Kyselka near Karlovy Vary at the western slope of the Doupovske hory, Bohemia (Czech Republic), and CO 2 -poor waters from two underground boreholes at Jachymov, Krusne hory, Bohemia, have been studied with the aim of characterizing the distribution of rare earth elements, yttrium, and H, O, C, Sr, Nd, Pb isotopes during the low-temperature alteration processes of the host rocks. Additionally, leaching experiments were performed at pH 3 on the granitic and basaltic host rocks from Kyselka and the granite of Jachymov. All REE patterns of the granite- and the basalt-derived waters from the Kyselka area are different from those of their source rocks and the leachates of the latter. This elucidates the inhomogeneous distribution of REE and Y among the solid phases in the altered magmatic rocks. The Eu and Ce anomalies in granite-derived waters are inherited, the Y anomaly is achieved by fluid migration. Yttrium is always preferentially leached by mineral waters, whereas Y/Ho ratios of rocks and their leachates are very similar. The REE abundances in waters from the wells in Jachymov are derived from rocks intensely leached and depleted in easily soluble REE-bearing minerals, whereas the granites and basalts from Kyselka still contain soluble, REE-bearing minerals. A comparison of REE/Ca patterns of the experimental leachates with those of the mineral waters elucidate the high retention of REE in rocks during water-rock interaction. In strongly altered rocks Sr isotope ratios of mineral waters and rocks differ widely, whereas the corresponding Nd isotope ratios are very similar. 207 Pb/ 208 Pb, 206 Pb/ 208 Pb and 206 Pb/ 207 Pb ratios in mineral waters are independent from U/Th ratios in the rocks. 206 Pb/ 208 Pb and 206 Pb/ 207 Pb are lower in mineral waters than in their source rocks and their leachates, which indicates that Pb is primarily derived from solid phases that do not contain significant contents of leachable U and Th

Rare Earth Element Geochemistry And Protoliths Of Schists In ...

African Journals Online (AJOL)

The Nigerian schist belts constitute the most important lithologic units necessary for the unravelling of the geochemical and geodynamic evolution of the basement complex. The schists have however undergone extensive alterations owing to weathering and metamorphism. REE abundance and distribution patterns of ...

Petrology and Geochemistry of Serpentinized Peridotites from a Bonin Fore-arc Seamount

Science.gov (United States)

Tian, L.; Tuoyu, W.; Dong, Y. H.; Gao, J.; Wu, S.

2016-12-01

Serpentinites, which contain up to 13 wt.% of water, are an important reservoir for chemical recycling in subduction zones. During the last two decades, many observations documented the occurrence of fore-arc mantle serpentinites in different locations. Here, we present petrology and whole rock chemistry for serpentinized peridotites dredged from the Hahajima Seamount, which is located 20-60 km west of the junction of the Bonin Trench and the Mariana Trench. Combined with published geochemical data of serpentinites from the Torishima Seamount, Conical Seamount and South Chamorro Seamount in the Izu-Bonin-Mariana fore-arc region, it will allow us to better understand the average composition of serpentinized fore-arc mantle overlying the subducting slab and the role of serpentinized mantle playing in the subduction zone geochemical cycle. The studied ultramafic rocks from the Hahajima Seamount are extensively serpentinized and hydrated (73 to 83%), with loss of ignition values ranging between 13 and 15 wt.%. Our results show that the serpentinized peridotites have Mg number from 88 to 90, and the average MgO/SiO2 is 0.93. The average Al2O3 (0.48 wt.%) and CaO (0.23 wt.%) contents are very low, consistent with low clinopyroxene abundances, and the overall depleted character of the mantle harzburgite protoliths. The serpentinized peridotites from the Hahajima Seamount exhibit similar "U" shape rare earth element (REE) patterns ([La/Sm]N = 3.1-3.6), at higher overall abundances, to the Conical and South Chamorro Seamount suites. One exceptional sample shows the similar REE pattern as serpentinized peridotites from the Torishima Seamount, with depleted light REE concentration ([La/Sm]N =0.7). All the serpentinized peridotites from these four fore-arc seamounts show strong enrichment in fluid-mobile and lithophile elements (U, Pb, Sr and Li). The geochemical signature of the serpentinized peridotites from the seamounts in the Izu-Bonin-Mariana fore-arc region could be

Specific genes involved in synthesis and editing of heparan sulfate proteoglycans show altered expression patterns in breast cancer

International Nuclear Information System (INIS)

Fernández-Vega, Iván; García, Olivia; Crespo, Ainara; Castañón, Sonia; Menéndez, Primitiva; Astudillo, Aurora; Quirós, Luis M

2013-01-01

, experienced a strong deregulation in all patients analyzed. IDCs show alterations in the expression of HSPG genes; principally the expression and localization of proteoglycans and the sulfation patterns of glycosaminoglycan chains, depending on the metastatic nature of the tumor. In addition, the anti-proliferative molecule heparanase 2 experiences strong deregulation, thus highlighting it as a potentially interesting diagnostic factor

Do manganese nodules grow or dissolve after burial? Results from the Central Indian Ocean Basin

Digital Repository Service at National Institute of Oceanography (India)

Pattan, J.N.; Parthiban, G.P.S.

(Elderfield et al., 1981; Glasby et al., 1987). We considered La as a representative element of the REE group because all of the 14 naturally occurring elements were not analysed in all of the studied samples. The mean La content in the buried nodules from red... carrier phase in buried nodules, we plotted La (representing REE group) against combined Fe+Ti+P contents, which shows a strong positive correlation (r = 0.88), suggesting a single REE carrier phase (Fig. 3). This is similar to the earlier observation...

Rare earth element studies of surficial sediments from the southwestern Carlsberg Ridge, Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Pattan, J.N.; Higgs, N.C.

content. REEs show a strong positive correlation with Al+Fe+K+Mg+Na (r sup(2)=0.98) and Mn+Fe+Cu+Ni (r sup(2)=0.86) suggesting that the REE is associated with a combined phase of clays (mainly illite) and Mn-Fe oxyhydroxides. The aeolian input...

Selective intake of potassium from K-bearing silicate minerals by sunflower and upland rice inferred from Eu anomaly. Implication for weathering as a direct consequence of plant physiology

International Nuclear Information System (INIS)

Akagi, Tasuku; Saito, Sakura; Watanabe, Shin-ichi; Sugiyama, Megumi; Ae, Noriharu

2006-01-01

Two crops (sunflower and upland rice) cultivated using three K-bearing minerals and KCl by Sugiyama and Ae (2000) were analyzed for rare earth elements (REEs). The two crops had been reported by them to general more available silica in soil (especially in the case of sunflower) and absorbed silica in plants (especially in the case of upland rice) than that available originally in soil. The K-bearing minerals included biotite, muscovite, and K-feldspar. The REE patterns of individual crop specimens exhibited different extents of Eu anomaly; upland rice exhibited more varying extent of Eu anomaly than sunflower. It is inferred that REEs released from the K-bearing minerals had a longer contact with soil in the case of sunflower than in the case of upland rice. By the scrutiny of the extent of the Eu anomaly, it was found that upland rice took in K and REEs from all the K-bearing minerals, including hardly-soluble feldspar. Eu anomaly can be a good proxy of sources of inorganic nutrients in plants as well as of the directness of absorption of the nutrients. When the present results are viewed from a different angle, they endorse that plant-induced weathering is equivalent to physiological action of plants. (author)

Rare earth elements determined in Antarctic ice by inductively coupled plasma-Time of flight, quadrupole and sector field-mass spectrometry: An inter-comparison study

International Nuclear Information System (INIS)

Dick, D.; Wegner, A.; Gabrielli, P.; Ruth, U.; Barbante, C.; Kriews, M.

2008-01-01

Inductively coupled plasma mass spectrometry (ICP-MS) is a suitable tool for multi-element analysis at low concentration levels. Rare earth element (REE) determinations in standard reference materials and small volumes of molten ice core samples from Antarctica have been performed with an ICP-time of flight-MS (ICP-TOF-MS) system. Recovery rates for REE in e.g. SPS-SW1 amounted to ∼103%, and the relative standard deviations were 3.4% for replicate analysis at REE concentrations in the lower ng L -1 range. Analyses of REE concentrations in Antarctic ice core samples showed that the ICP-TOF-MS technique meets the demands of restricted sample mass. The data obtained are in good agreement with ICP-Quadrupole-MS (ICP-Q-MS) and ICP-Sector Field-MS (ICP-SF-MS) results. The ICP-TOF-MS system determines accurately and precisely REE concentrations exceeding 5 ng L -1 while between 0.5 and 5 ng L -1 accuracy and precision are element dependent

Using Nd-Sr isotopes and rare earth elements to study sediment provenance of the modern radial sand ridges in the southwestern Yellow Sea

International Nuclear Information System (INIS)

Rao, Wenbo; Mao, Changping; Wang, Yigang; Huang, Huiming; Ji, Junfeng

2017-01-01

The radial sand ridges (RSRs) in the southwestern Yellow Sea off the Jiangsu Coast, East China have been intensively studied at least since 1975. Despite decades of studies, the provenance of the RSR sediments remains uncertain. In this study, the Nd-Sr isotopic and REE geochemical compositions of residual sediments (i.e., the acid-insoluble fractions) were investigated to determine the provenance of the RSR sediments. The Nd isotopic composition, PAAS-normalized REE patterns and characteristic parameters (e.g., Sm/Nd, (La/Sm)_N, (Gd/Yb)_N) were merely associated with source rocks but not with particle sorting while the Sr isotopic composition and REE contents of residual sediments were affected by particle sorting in addition to source rocks. The onshore RSR sediments originated mainly from mixing of the fine-grained sediments from various parts of the offshore RSR in terms of REE geochemical and isotopic analyses. Isotopic and REE geochemical comparison further reveals that the RSRs off the Jiangsu Coast were fed chiefly by the dispersal of surface sediments from the Yangtze River Mouth. Surface sediments from the Yangtze River Mouth were directly dispersed to the RSRs along the Jiangsu Coast and significantly affected the seaward part of the offshore RSR and the old Yellow River Delta area by a northward branch of the Changjiang Diluted Freshwater Plume. Only minor quantities of surface sediments from the modern Yellow River Mouth were introduced into the RSRs by the Jiangsu Coastal Current and mainly contaminated the landward part of the offshore RSR area. Our findings highlighted the potential of the Nd isotopes with REE geochemistry to trace the provenance of coastal sediments. - Highlights: • Nd isotopic and REE geochemical compositions of coastal and estuary sediments are mainly associated with source rocks. • Onshore RSR sediments originate from mixing of fine-grained sediments from various parts of the offshore RSR. • The RSRs off the Jiangsu Coast

Rare earth element and uranium-thorium variations in tufa deposits from the Mono Basin, CA

Science.gov (United States)

Wilcox, E. S.; Tomascak, P. B.; Hemming, N.; Hemming, S. R.; Rasbury, T.; Stine, S.; Zimmerman, S. R.

2009-12-01

Samples of fossil tufa deposits from several localities in the Mono Basin, eastern California, were analyzed for trace element concentrations in order to better understand changes in lake composition in the past. These deposits were formed during the last glacial cycle, mostly during deglaciation (Benson et al., 1990, PPP). Three elevations are represented by the analyses. Samples from near Highway 167 were sampled between 2063 and 2069 m asl. Samples from near Thompson Road were sampled between 2015 and 2021 m. One layered mound was sampled at 1955 m. Concentrations of the lanthanide rare earth elements (REE), in particular the heavy/light (HREE/LREE) distributions, have been shown to be sensitive to alkalinity in modern saline lakes (e.g., Johannesson et al., 1994, GRL, 21, 773-776), and the same has been suggested for U/Th (Anderson et al., 1982, Science, 216, 514-516). Holocene to near-modern tufa towers exist in shallow water and around the current shoreline (1945 m). Tufa towers above 2000 m include a characteristic morphology termed thinolite, interpreted to represent pseudomorphs after the very cold water mineral ikaite. Most lower elevation towers do not have the thinolite morphology, but some layered tufa mounds at low elevations include several layers of thinolite, such as the one sampled for this project. Analyses were made on millimeter-scale bulk samples from tufa towers. Measurements were made on sample solutions with a Varian 820MS quadrupole ICP-MS. Mono Basin tufa samples have total REE concentrations ranging from 0.029 to 0.77 times average shales. Samples have flat to moderately HREE-enriched shale-normalized patterns with limited overall variability ([La/Lu]SN of 1.8 to 9.6) but with some variability in the slope of the HREE portion of the patterns. Tufa towers sampled from three elevations have (Gd/Lu)SN of 0.40 to 1.5. The REE patterns of most samples have small positive Ce anomalies, but a minority of samples, all from the layered tufa mound

ICP-AES determination of rare earth elements in coal fly ash samples of thermal power stations: assessment of possible recovery and environmental impact of rare earth elements

International Nuclear Information System (INIS)

Premadas, A.; Mary, Thomas Anitha; Chakrapani, G.

2013-01-01

Accurate determination of rare earth elements (REEs) in ashes of thermal power plants is important in the current scenario due to its economic value, and the pollution caused if they are released in to the environment. Their toxicity to living organisms now gaining importance in international community, and some investigation shows it causes retardation in plant growth. In coal based thermal stations huge quantity of coal used annually as a fuel and lakhs of tones of waste is generated in the form of ashes. Therefore studies were carried out on three aspects - fairly rapid and accurate ICP-AES determination REEs in coal fly ash samples using addition technique, a preliminary acid leaching studies on coal received from three different fired thermal power stations using hydrochloric acid at pH 1 and 2, and quantify the REEs leached, and economic recovery of REEs using di-(2-ethylhexyl) phosphoric acid solvent extraction process or precipitation hydroxides using dilute ammonia solution. The standard addition method of REEs determination using rate and reproducible values, besides the analysis is fast compared to the ion exchange separation of REEs followed by the ICP-AES determination. (author)

Highly fractionated rare-earth elements in ferromagnesian chondrules from the Felix (CO3) meteorite

International Nuclear Information System (INIS)

Misawa, Keiji; Nakamura, Noboru

1988-01-01

Here we describe two ferromagnesian chondrules from the Felix (Ornans-subtype) carbonaceous chondrite which carry a marker signature of REE (rare earth element) fractionation in the nebula. Both show positive Ce and Yb anomalies and one exhibits a light/heavy REE fractionation. On the basis of the REE characteristics of these chondrules, as well as those of the authors' work on Allende (CV) [N Geochim. Cosmochim. Acta. in press], we suggest that one of the precursor materials of chondrules in CO-CV carbonaceous chondrites is a high-temperature condensate from the nebular gas. (author)

MicroRNAs show mutually exclusive expression patterns in the brain of adult male rats

DEFF Research Database (Denmark)

Olsen, Line; Klausen, Mikkel; Helboe, Lone

2009-01-01

BACKGROUND: The brain is a major site of microRNA (miRNA) gene expression, but the spatial expression patterns of miRNAs within the brain have not yet been fully covered. METHODOLOGY/PRINCIPAL FINDINGS: We have characterized the regional expression profiles of miRNAs in five distinct regions...... of the adult rat brain: amygdala, cerebellum, hippocampus, hypothalamus and substantia nigra. Microarray profiling uncovered 48 miRNAs displaying more than three-fold enrichment between two or more brain regions. Notably, we found reciprocal expression profiles for a subset of the miRNAs predominantly found...... (> ten times) in either the cerebellum (miR-206 and miR-497) or the forebrain regions (miR-132, miR-212, miR-221 and miR-222). CONCLUSIONS/SIGNIFICANCE: The results indicate that some miRNAs could be important for area-specific functions in the brain. Our data, combined with previous studies in mice...

Rees valuations

Indian Academy of Sciences (India)

In the above phrase 'give rise to', we are trying to mimic Max Noether's ...... posia in Pure Mathematics, American Mathematical Society (1983) vol 40, ... [23] Le D T and Weber C, A geometrical approach to the Jacobian conjecture for n = 2,.

Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water

International Nuclear Information System (INIS)

Merschel, Gila; Bau, Michael

2015-01-01

High-technology metals — such as the rare earth elements (REE) — have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. - Highlights: • Corbicula fluminea shells are bioarchives of dissolved geogenic REE in

Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water

Energy Technology Data Exchange (ETDEWEB)

Merschel, Gila, E-mail: g.merschel@jacobs-university.de; Bau, Michael

2015-11-15

High-technology metals — such as the rare earth elements (REE) — have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. - Highlights: • Corbicula fluminea shells are bioarchives of dissolved geogenic REE in

Direct Quantification of Rare Earth Elements Concentrations in Urine of Workers Manufacturing Cerium, Lanthanum Oxide Ultrafine and Nanoparticles by a Developed and Validated ICP-MS

Science.gov (United States)

Li, Yan; Yu, Hua; Zheng, Siqian; Miao, Yang; Yin, Shi; Li, Peng; Bian, Ying

2016-01-01

Rare earth elements (REEs) have undergone a steady spread in several industrial, agriculture and medical applications. With the aim of exploring a sensitive and reliable indicator of estimating exposure level to REEs, a simple, accurate and specific ICP-MS method for simultaneous direct quantification of 15 REEs (89Y, 139La, 140Ce, 141Pr, 146Nd, 147Sm, 153Eu, 157Gd, 159Tb, 163Dy, 165Ho, 166Er, 169Tm, 172Yb and 175Lu) in human urine has been developed and validated. The method showed good linearity for all REEs in human urine in the concentrations ranging from 0.001–1.000 μg∙L−1 with r2 > 0.997. The limits of detection and quantification for this method were in the range of 0.009–0.010 μg∙L−1 and 0.029–0.037 μg∙L−1, the recoveries on spiked samples of the 15 REEs ranged from 93.3% to 103.0% and the relative percentage differences were less than 6.2% in duplicate samples, and the intra- and inter-day variations of the analysis were less than 1.28% and less than 0.85% for all REEs, respectively. The developed method was successfully applied to the determination of 15 REEs in 31 urine samples obtained from the control subjects and the workers engaged in work with manufacturing of ultrafine and nanoparticles containing cerium and lanthanum oxide. The results suggested that only the urinary levels of La (1.234 ± 0.626 μg∙L−1), Ce (1.492 ± 0.995 μg∙L−1), Nd (0.014 ± 0.009 μg∙L−1) and Gd (0.023 ± 0.010 μg∙L−1) among the exposed workers were significantly higher (p < 0.05) than the levels measured in the control subjects. From these, La and Ce were the primary components, and accounted for 88% of the total REEs. Lanthanum comprised 27% of the total REEs while Ce made up the majority of REE content at 61%. The remaining elements only made up 1% each, with the exception of Dy which was not detected. Comparison with the previously published data, the levels of urinary La and Ce in workers and the control subjects show a higher trend

Geochemistry, Nd-Pb Isotopes, and Pb-Pb Ages of the Mesoproterozoic Pea Ridge Iron Oxide-Apatite–Rare Earth Element Deposit, Southeast Missouri

Science.gov (United States)