Sample records for earth element content

  1. [Rare earth elements content in farmland soils and crops of the surrounding copper mining and smelting plant in Jiangxi province and evaluation of its ecological risk].

    PubMed

    Jin, Shu-Lan; Huang, Yi-Zong; Wang, Fei; Xu, Feng; Wang, Xiao-Ling; Gao, Zhu; Hu, Ying; Qiao Min; Li, Jin; Xiang, Meng

    2015-03-01

    Rare earth elements content in farmland soils and crops of the surrounding copper mining and smelting plant in Jiangxi province was studied. The results showed that copper mining and smelting could increase the content of rare earth elements in soils and crops. Rare earth elements content in farmland soils of the surrounding Yinshan Lead Zinc Copper Mine and Guixi Smelting Plant varied from 112.42 to 397.02 mg x kg(-1) and 48.81 to 250.06 mg x kg(-1), and the average content was 254.84 mg x kg(-1) and 144.21 mg x kg(-1), respectively. The average contents of rare earth elements in soils in these two areas were 1.21 times and 0.68 times of the background value in Jiangxi province, 1.36 times and 0.77 times of the domestic background value, 3.59 times and 2.03 times of the control samples, respectively. Rare earth elements content in 10 crops of the surrounding Guixi Smelting Plant varied from 0.35 to 2.87 mg x kg(-1). The contents of rare earth elements in the leaves of crops were higher than those in stem and root. The contents of rare earth elements in Tomato, lettuce leaves and radish leaves were respectively 2.87 mg x kg(-1), 1.58 mg x kg(-1) and 0.80 mg x kg(-1), which were well above the hygienic standard limit of rare earth elements in vegetables and fruits (0.70 mg x kg(-1)). According to the health risk assessment method recommended by America Environmental Protection Bureau (USEPA), we found that the residents' lifelong average daily intake of rare earth elements was 17.72 mg x (kg x d)(-1), lower than the critical value of rare earth elements damage to human health. The results suggested that people must pay attention to the impact of rare earth elements on the surrounding environment when they mine and smelt copper ore in Jiangxi.

  2. [Application of ICP-MS to Detect Rare Earth Elements in Three Economic Macroalgaes in China].

    PubMed

    Zhao, Yan-fang; Shang, De-rong; Zhai, Yu-xiu; Ning, Jin-song; Ding, Hai-yan; Sheng, Xiao-feng

    2015-11-01

    In order to investigate the content and distribution of rare earth elements (REE) in main economic macroalgaes in our country, fifteen rare earth elements in three economic macroalgaes (including 30 samples of kelp, 30 samples of laver and 15 samples of Enteromorpha) were detected using ICP-MS method. Results showed that the total content of REE in different species of macroalgaes was different. The highest total content of REE was in Enteromorpha (16,012.0 ng · g⁻¹), while in kelp and laver, the total REE was similar for two macroalgaes (3887.4 and 4318.1 ng · g⁻¹ respectively). The content of fifteen rare earth elements in kelp ranged from 7.9 to 1496.4 ng · g⁻¹; in laver, it ranged from 8.2 to 1836.6 ng · g⁻¹. For Enteromorpha, the concentration of 15 rare earth elements were between 19.2 and 6014.5 ng · g⁻¹. In addition, the content and distribution of different rare earth elements in different macroalgaes was also different. For kelp, the highest content of REE was Ce (1 496.4 ng · g⁻¹), and the second was La (689.1 ng · g⁻¹). For laver, the highest was Y (1836.6 ng · g⁻¹), and the second was Ce (682.2 ng · g⁻¹). For Enteromorpha, the highest was Ce (6014.5 ng · g⁻¹), and the second was La (2902.9 ng · g⁻¹). Present results also showed that three macroalgaes accumulated the light rare earth elements much more than the high rare earth elements. The light rare earth elements occupied 90.9%, 87.3% and 91.1% for kelp, laver and Enteromorpha respectively. The result that the Enteromorpha had high content of rare earth elements could provide important support for opening new research directions for the utilization of Enteromorpha.

  3. Rare Earth Elements | Alaska Division of Geological & Geophysical Surveys

    Science.gov Websites

    - Mineral Resources main content Rare Earth Elements Rare earth elements and the supply and demand of these deposits containing rare earth elements to meet the perceived future demand. High prices for rare earth earth element occurrences in the DGGS publications catalog. Department of Natural Resources, Division of

  4. A comprehensive analysis of the content of heavy rare-earth elements and platinum in snow samples to assess the ecological hazard of air pollution in urban areas

    NASA Astrophysics Data System (ADS)

    Vinokurov, S. F.; Tarasova, N. P.; Trunova, A. N.; Sychkova, V. A.

    2017-07-01

    Snow samples from the territory of the Setun River Valley Wildlife Sanctuary are analyzed for the content of rare-earth elements, heavy metals, and other hazardous elements by the inductively coupled plasma mass-spectrometry method. The changes in the concentrations of rare-earth elements, Pt, Pd, and indicator ratios of elements in the solid fractions of snow are revealed. A trend toward a decrease in the content of several elements northeastward of the Moscow Ring Road (MRR) is established. The level of seasonal atmospheric contamination of the area under study is assessed, and a possible source is identified.

  5. [Contents of macromineral and trace elements in spirulina (Arthrospira platensis) from France, Chad, Togo, Niger, Mali, Burkina-Faso and Central African Republic].

    PubMed

    Vicat, Jean-Paul; Doumnang Mbaigane, Jean-Claude; Bellion, Yves

    2014-01-01

    Data on mineral elements in spirulinas being limited, we analyzed macrominerals and trace elements of samples from France and Africa. Spirulinas cultivated in France have a composition in macromineral elements similar to those of the literature. The entire contents of trace elements are low. Unlike marine cyanobacteria, they do not concentrate rare-earth elements. Spirulina harvested in Chad has high levels in macrominerals and trace elements, due to traditional drying and harvesting methods. Rare-earth element levels are attributed to this pollution and not to their concentration in spirulinas, because rare-earth element normalized profiles of spirulina are strictly parallel to those of ouadis mud and very different from those of ouadis water. Despite the sometimes high content of total As, normal water consumption in Chad presents no health problems. Spirulinas grown in Togo, Niger, Mali, Burkina-Faso and Central African Republic have chemical compositions similar to those of Chad spirulinas, but with a lower content of macromineral and trace elements, reflecting a lower mineral pollution. Rare-earth element normalized patterns dismiss an aeolian pollution and the pollution is rather of pedological origin. They show no toxicity problem except spirulinas from Burkina-Faso, whose Pb content is too high. The variability of composition of spirulinas can be largely attributed to the mineral pollution of the samples. Significant levels of rare-earth elements sometimes found in the literature reflect this pollution. Copyright © 2013 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  6. [Rare earth elements contents and distribution characteristics in nasopharyngeal carcinoma tissue].

    PubMed

    Zhang, Xiangmin; Lan, Xiaolin; Zhang, Lingzhen; Xiao, Fufu; Zhong, Zhaoming; Ye, Guilin; Li, Zong; Li, Shaojin

    2016-03-01

    To investigate the rare earth elements(REEs) contents and distribution characteristics in nasopharyngeal carcinoma( NPC) tissue in Gannan region. Thirty patients of NPC in Gannan region were included in this study. The REEs contents were measured by tandem mass spectrometer inductively coupled plasma(ICP-MS/MS) in 30 patients, and the REEs contents and distribution were analyzed. The average standard deviation value of REEs in lung cancer and normal lung tissues was the minimum mostly. Light REEs content was higher than the medium REEs, and medium REEs content was higher than the heavy REEs content. REEs contents changes in nasopharyngeal carcinoma were variable obviously, the absolute value of Nd, Ce, Pr, Gd and other light rare earth elements were variable widely. The degree of changes on Yb, Tb, Ho and other heavy rare earth elements were variable widely, and there was presence of Eu, Ce negative anomaly(δEu=0. 385 5, δCe= 0. 523 4). The distribution characteristic of REEs contents in NPC patients is consistent with the parity distribution. With increasing atomic sequence, the content is decline wavy. Their distribution patterns were a lack of heavy REEs and enrichment of light REEs, and there was Eu , Ce negative anomaly.

  7. [Analysis of X-Ray Fluorescence Spectroscopy and Plasma Mass Spectrometry of Pangxidong Composite Granitoid Pluton and Its Implications for Magmatic Differentiation].

    PubMed

    Zeng, Chang-yu; Ding, Ru-xin; Li, Hong-zhong; Zhou, Yong-zhang; Niu, Jia; Zhang, Jie-tang

    2015-11-01

    Pangxidong composite granitoid pluton located in the southwestern margin of Yunkai massif. The metamorphic grade of this pluton increases from outside to inside, that is, banded-augen granitic gneisses, gneissoid granites and granites distribute in order from edge to core. X-Ray Fluorescence Spectroscopy and Plasma Mass Spectrometry are conducted to study the geochemical characteristics of the three types of rocks. The result shows that all the three types of rocks are peraluminous rocks and their contents of main elements and rare earth elements change gradually. From granitic gneisses to granites, the contents of Al₂O₃, CaO, MgO, TiO₂, total rare earth elements and light rare earth elements increase, but the contents of SiO₂ and heavy rare earth elements decrease. It is suggested that the phylogenetic relationship exists between granitic gneisses, gneissoid granites and granites during the multi-stage tectonic evolution process. Furthermore, the remelting of metamorphosed supracrustal rocks in Yunkai massif is probably an important cause of granitoid rocks forming. The evolutionary mechanism is probably that SiO₂ and heavy rare earth elements were melt out from the protolith and gradually enriched upward, but Al₂O₃, CaO, MgO, TiO₂ and light rare earth elements enriched downward.

  8. Google Earth locations of USA and seafloor hydrothermal vents with associated rare earth element data

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Andrew Fowler

    Google Earth .kmz files that contain the locations of geothermal wells and thermal springs in the USA, and seafloor hydrothermal vents that have associated rare earth element data. The file does not contain the actual data, the actual data is available through the GDR website in two tier 3 data sets entitled "Compilation of Rare Earth Element Analyses from US Geothermal Fields and Mid Ocean Ridge (MOR) Hydrothermal Vents" and "Rare earth element content of thermal fluids from Surprise Valley, California"

  9. Composition of monazites from pegmatites in eastern Minas Gerais, Brazil

    USGS Publications Warehouse

    Murata, K.J.; Dutra, C.V.; da Costa, M.T.; Branco, J.J.R.

    1959-01-01

    Two zoned pegmatites in south-eastern Minas Gerais were sampled in detail for their content of monazite and xenotime and the monazite was analysed for certain of the rare-earth elements and thorium. The ratio of xenotime to monazite increases in both pegmatites from the wall toward the quartz core. The content of the less basic rare-earth elements and of thorium in monazite rises in the same direction. These variation trends suggest that during the crystallization of these pegmatites there was a fractionation of the elements leading to a more or less steady enrichment of the less basic rare-earth elements and of thorium in the residual fluids. One mode of explaining these observed effects postulates that the rare-earth elements and thorium were present in pegmatitic fluids as co-ordination complexes rather than as simple cations. ?? 1959.

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    Depletions of volatile siderophile elements (VSE; Ga, Ge, In, As, Sb, Sn, Bi, Zn, Cu, Cd) in mantles of Earth and Moon, constrain the origin of volatile elements in these bodies, and the overall depletion of volatile elements in Moon relative to Earth. A satisfactory explanation has remained elusive [1,2]. We examine the depletions of VSE in Earth and Moon and quantify the amount of depletion due to core formation and volatility of potential building blocks. We calculate the composition of the Earth's PUM during continuous accretion scenarios with constant and variable fO2. Results suggest that the VSE can be explained by a rather simple scenario of continuous accretion leading to a high PT metal-silicate equilibrium scenario that establishes the siderophile element content of Earth's PUM near the end of accretion [3]. Core formation models for the Moon explain most VSE, but calculated contents of In, Sn, and Zn (all with Tc < 750 K) are all still too high after core formation, and must therefore require an additional process to explain the depletions in the lunar mantle. We discuss possible processes including magmatic degassing, evaporation, condensation, and vapor-liquid fractionation in the lunar disk.

  11. Evaluation of Rare Earth Element Extraction from North Dakota Coal-Related Feed Stocks

    NASA Astrophysics Data System (ADS)

    Laudal, Daniel A.

    The rare earth elements consist of the lanthanide series of elements with atomic numbers from 57-71 and also include yttrium and scandium. Due to their unique properties, rare earth elements are crucial materials in an incredible array of consumer goods, energy system components and military defense applications. However, the global production and entire value chain for rare earth elements is dominated by China, with the U.S. currently 100% import reliant for these critical materials. Traditional mineral ores including previously mined deposits in the U.S., however, have several challenges. Chief among these is that the content of the most critical and valuable of the rare earths are deficient, making mining uneconomical. Further, the supply of these most critical rare earths is nearly 100% produced in China from a single resource that is only projected to last another 10 to 20 years. The U.S. currently considers the rare earths market an issue of national security. It is imperative that alternative domestic sources of rare earths be identified and methods developed to produce them. Recently, coal and coal byproducts have been identified as one of these promising alternative resources. This dissertation details a study on evaluation of the technical and economic feasibility of rare earth element recovery from North Dakota lignite coal and lignite-related feedstocks. There were four major goals of this study: i) identify lignite or lignite-related feedstocks with total rare earth element content above 300 parts per million, a threshold dictated by the agency who funded this research as the minimum for economic viability, ii) determine the geochemistry of the feedstocks and understand the forms and modes of occurrence of the rare earth elements, information necessary to inform the development of extraction and concentration methods, iii) identify processing methods to concentrate the rare earth elements from the feedstocks to a target of two weight percent, a value that would be sufficient to leverage existing separation and refining methods developed for the traditional mineral ore industry, and iv) develop a process that is economically viable and environmentally benign. To achieve these overall goals, and to prove or disprove the research hypotheses, the research scope was broken down into three main efforts: i) sampling and characterization of potential feedstocks, ii) laboratory-scale development and testing of rare earth element extraction and concentration methods, and iii) process design and technical and economic feasibility evaluation. In total, 174 unique samples were collected, and several locations were identified that exceeded the 300 ppm total rare earth elements target. The results showed that on a whole sample basis, the rare earths are most concentrated in the clay-rich sediments associated with the coal seams, but on an ash basis in certain locations within certain coal seams the content is significantly higher, an unexpected finding given prior research. At Falkirk Mine near Underwood, North Dakota three coal seams were found to have elevated levels of rare earths, ranging from about 300 to 600 ppm on an ash basis. Additionally, exceptionally high rare earths content was found in samples collected from an outcropping of the Harmon-Hansen coal zone in southwestern North Dakota that contained 2300 ppm on an ash basis. The results dictated that extraction and concentration methods be developed for these rare earth element-rich coals, instead of the mineral-rich sediments. This effort also found that at a commercial-scale, due to non-uniformity of the rare earths content stratigraphically in the coal seams, selective mining practices will be needed to target specific locations within the seams. The bulk mining and blending practices as Falkirk Mine result in a relatively low total rare earths content in the feed coal entering the Coal Creek Power Station adjacent to the mine. Characterization of the coal samples identified that the predominant modes of rare earths occurrence in the lignite coals are associations with the organic matter, primarily as coordination complexes and a lesser amount as ion-exchangeable cations on oxygen functional groups. Overall it appears that about 80-95% of rare earths content in North Dakota lignite is organically associated, and not present in mineral forms, which due to the weak organic bonding, presented a unique opportunity for extraction. The process developed for extraction of rare earths was applied to the raw lignite coals instead of fly ash or other byproducts being investigated extensively in the literature. Rather, the process uses a dilute acid leaching process to strip the organically associated rare earths from the lignite with very high efficiency of about 70-90% at equilibrium contact times. Although the extraction kinetics are quite fast given commercial leaching operations, there is some tradeoff between extraction efficiency and contact time. (Abstract shortened by ProQuest.).

  12. Leaching behavior of rare earth elements in Fort Union lignite coals of North America

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Laudal, Daniel A.; Benson, Steven A.; Addleman, Raymond Shane

    Rare earth elements are crucial materials in an incredible array of consumer goods, energy system components and military defense applications. However, the global production and entire value chain for rare earth elements is dominated by China, with the U.S. currently 100% import reliant for these critical materials. Traditional mineral ores including those previously mined in the U.S., however, have several challenges. Chief among these is that the content of the most critical and valuable of the rare earths are deficient, making mining uneconomical. Further, the supply of these most critical rare earths is nearly 100% produced in China from amore » single resource that is only projected to last another 10 to 20 years. The U.S. currently considers the rare earths market an issue of national security. It is imperative that alternative domestic sources of rare earths be identified and methods developed to produce them. Recently, coal and coal byproducts have been identified as one of these promising alternative resources. This paper details the results of a study on characterization of North Dakota lignite and lignite-related feedstocks as an assessment of their feasibility for rare earth element recovery. The abundance, distribution and modes of occurrence of the rare earth elements in the samples collected were determined in this initial study to inform the selection of appropriate extraction and concentration methods to recover the rare earth elements. Materials investigated include the lignite coals, clay-rich sediments associated with the coal seams, and materials associated with a lignite beneficiation system and power plant. The results show that high rare earth element levels exist both in lignite coals and associated sediments. The form of the rare earth elements in the clay materials is primarily as ultra-fine mineral grains. In the lignite coals, approximately 80-95% of the rare earths content is organically associated, primarily as coordination complexes.« less

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

    PubMed

    Franus, Wojciech; Wiatros-Motyka, Małgorzata M; Wdowin, Magdalena

    2015-06-01

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

  14. Health risk assessment of rare earth elements in cereals from mining area in Shandong, China.

    PubMed

    Zhuang, Maoqiang; Wang, Liansen; Wu, Guangjian; Wang, Kebo; Jiang, Xiaofeng; Liu, Taibin; Xiao, Peirui; Yu, Lianlong; Jiang, Ying; Song, Jian; Zhang, Junli; Zhou, Jingyang; Zhao, Jinshan; Chu, Zunhua

    2017-08-29

    To investigate the concentrations of rare earth elements in cereals and assess human health risk through cereal consumption, a total of 327 cereal samples were collected from rare earth mining area and control area in Shandong, China. The contents of 14 rare earth elements were determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The medians of total rare earth elements in cereals from mining and control areas were 74.22 μg/kg and 47.83 μg/kg, respectively, and the difference was statistically significant (P < 0.05). The wheat had the highest rare earth elements concentrations (109.39 μg/kg and 77.96 μg/kg for mining and control areas, respectively) and maize had the lowest rare earth elements concentrations (42.88 μg/kg and 30.25 μg/kg for mining and control areas, respectively). The rare earth elements distribution patterns for both areas were characterized by enrichment of light rare earth elements. The health risk assessment demonstrated that the estimated daily intakes of rare earth elements through cereal consumption were considerably lower than the acceptable daily intake (70 μg/kg bw). The damage to adults can be neglected, but more attention should be paid to the effects of continuous exposure to rare earth elements on children.

  15. Rare earth element content of cryptocrystalline magnesites of Konya, Turkey

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zedef, Veysel, E-mail: vzedef@selcuk.edu.tr; Russell, Michael

    We examined the rare earth element content of several cryptocrystalline magnesites as well as hydromagnesite, host rock serpentinites, lake water and hot spring water from Turkey. Southwestern Turkey hosts cryptocrystalline magnesites, sedimentary magnesites with presently forming, biologically mediated hydromagnesites and travertines. Our results show the REE content of the minerals, rocks and waters are well below detection limits. One hydromagnesite sample from Lake Salda has slightly high La (2.38ppb), Ce (3.91 ppb) and Nd (1.68 ppb) when compared to other samples, but these are also still below detection limits of the method we followed.

  16. Phase characteristics of rare earth elements in metallic fuel for a sodium-cooled fast reactor by injection casting

    NASA Astrophysics Data System (ADS)

    Kuk, Seoung Woo; Kim, Ki Hwan; Kim, Jong Hwan; Song, Hoon; Oh, Seok Jin; Park, Jeong-Yong; Lee, Chan Bock; Youn, Young-Sang; Kim, Jong-Yun

    2017-04-01

    Uranium-zirconium-rare earth (U-Zr-RE) fuel slugs for a sodium-cooled fast reactor were manufactured using a modified injection casting method, and investigated with respect to their uniformity, distribution, composition, and phase behavior according to RE content. Nd, Ce, Pr, and La were chosen as four representative lanthanide elements because they are considered to be major RE components of fuel ingots after pyroprocessing. Immiscible layers were found on the top layers of the melt-residue commensurate with higher fuel slug RE content. Scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS) data showed that RE elements in the melt-residue were distributed uniformly throughout the fuel slugs. RE element agglomeration did not contaminate the fuel slugs but strongly affected the RE content of the slugs.

  17. Uncovering the Chemistry of Earth-like Planets

    NASA Astrophysics Data System (ADS)

    Zeng, Li; Sasselov, Dimitar; Jacobsen, Stein

    2015-08-01

    We propose to use the evidence from our solar system to understand exoplanets, and in particular, to predict their surface chemistry and thereby the possibility of life. An Earth-like planet, born from the same nebula as its host star, is composed primarily of silicate rocks and an iron-nickel metal core, and depleted in volatile content in a systematic manner. The more volatile (easier to vaporize or dissociate into gas form) an element is in an Earth-like planet, the more depleted the element is compared to its host star. After depletion, an Earth-like planet would go through the process of core formation due to heat from radioactive decay and collisions. Core formation depletes a planet’s rocky mantle of siderophile (iron-loving) elements, in addition to the volatile depletion. After that, Earth-like planets likely accrete some volatile-rich materials, called “late veneer”. The late veneer could be essential to the origins of life on Earth and Earth-like planets, as it also delivers the volatiles such as nitrogen, sulfur, carbon and water to the planet’s surface, which are crucial for life to occur. Here we build an integrative model of Earth-like planets from the bottom up. Thus the chemical compositions of Earth-like planets could be inferred from their mass-radius relations and their host stars’ elemental abundances, and the origins of volatile contents (especially water) on their surfaces could be understood, and thereby shed light on the origins of life on them. This elemental abundance model could be applied to other rocky exoplanets in exoplanet systems.

  18. Uncovering the Chemistry of Earth-like Planets

    NASA Astrophysics Data System (ADS)

    Zeng, L.; Jacobsen, S. B.; Sasselov, D. D.

    2015-12-01

    We propose to use the evidence from our solar system to understand exoplanets, and in particular, to predict their surface chemistry and thereby the possibility of life. An Earth-like planet, born from the same nebula as its host star, is composed primarily of silicate rocks and an iron-nickel metal core, and depleted in volatile content in a systematic manner. The more volatile (easier to vaporize or dissociate into gas form) an element is in an Earth-like planet, the more depleted the element is compared to its host star. After depletion, an Earth-like planet would go through the process of core formation due to heat from radioactive decay and collisions. Core formation depletes a planet's rocky mantle of siderophile (iron-loving) elements, in addition to the volatile depletion. After that, Earth-like planets likely accrete some volatile-rich materials, called "late veneer". The late veneer could be essential to the origins of life on Earth and Earth-like planets, as it also delivers the volatiles such as nitrogen, sulfur, carbon and water to the planet's surface, which are crucial for life to occur. Here we build an integrative model of Earth-like planets from the bottom up. Thus the chemical compositions of Earth-like planets could be inferred from their mass-radius relations and their host stars' elemental abundances, and the origins of volatile contents (especially water) on their surfaces could be understood, and thereby shed light on the origins of life on them. This elemental abundance model could be applied to other rocky exoplanets in exoplanet systems.

  19. Uncovering the Chemistry of Earth-like Planets

    NASA Astrophysics Data System (ADS)

    Zeng, Li; Jacobsen, Stein; Sasselov, Dimitar D.

    2015-01-01

    We propose to use evidence from our solar system to understand exoplanets, and in particular, to predict their surface chemistry and thereby the possibility of life. An Earth-like planet, born from the same nebula as its host star, is composed primarily of silicate rocks and an iron-nickel metal core, and depleted in volatile content in a systematic manner. The more volatile (easier to vaporize or dissociate into gas form) an element is in an Earth-like planet, the more depleted the element is compared to its host star. After depletion, an Earth-like planet would go through the process of core formation due to heat from radioactive decay and collisions. Core formation depletes a planet's rocky mantle of siderophile (iron-loving) elements, in addition to the volatile depletion. After that, Earth-like planets likely accrete some volatile-rich materials, called 'late veneer'. The late veneer could be essential to the origins of life on Earth and Earth-like planets, as it also delivers the volatiles such as nitrogen, sulfur, carbon and water to the planet's surface, which are crucial for life to occur. We plan to build an integrative model of Earth-like planets from the bottom up. We would like to infer their chemical compositions from their mass-radius relations and their host stars' elemental abundances, and understand the origins of volatile contents (especially water) on their surfaces, and thereby shed light on the origins of life on them.

  20. Fast and simultaneously determination of light and heavy rare earth elements in monazite using combination of ultraviolet-visible spectrophotometry and multivariate analysis

    NASA Astrophysics Data System (ADS)

    Anggraeni, Anni; Arianto, Fernando; Mutalib, Abdul; Pratomo, Uji; Bahti, Husein H.

    2017-05-01

    Rare Earth Elements (REE) are elements that a lot of function for life, such as metallurgy, optical devices, and manufacture of electronic devices. Sources of REE is present in the mineral, in which each element has similar properties. Currently, to determining the content of REE is used instruments such as ICP-OES, ICP-MS, XRF, and HPLC. But in each instruments, there are still have some weaknesses. Therefore we need an alternative analytical method for the determination of rare earth metal content, one of them is by a combination of UV-Visible spectrophotometry and multivariate analysis, including Principal Component Analysis (PCA), Principal Component Regression (PCR), and Partial Least Square Regression (PLS). The purpose of this experiment is to determine the content of light and medium rare earth elements in the mineral monazite without chemical separation by using a combination of multivariate analysis and UV-Visible spectrophotometric methods. Training set created 22 variations of concentration and absorbance was measured using a UV-Vis spectrophotometer, then the data is processed by PCA, PCR, and PLSR. The results were compared and validated to obtain the mathematical equation with the smallest percent error. From this experiment, mathematical equation used PLS methods was better than PCR after validated, which has RMSE value for La, Ce, Pr, Nd, Gd, Sm, Eu, and Tb respectively 0.095; 0.573; 0.538; 0.440; 3.387; 1.240; 1.870; and 0.639.

  1. Sulfide Melts and Chalcophile Element Behavior in High Temperature Systems

    NASA Astrophysics Data System (ADS)

    Wood, B. J.; Kiseeva, K.

    2016-12-01

    We recently found that partition coefficients (Di) of many weakly and moderately chalcophile elements (e.g., Cd, Zn, Co, Cr, Pb, Sb, In) between sulfide and silicate melts are simple functions of the FeO content of the silicate liquid: logDi A-Blog[FeO] where [FeO] is the FeO concentration in the silicate, A and B are constants and the latter is related to the valency of the element of interest. In contrast, some strongly chalcophile (e.g Cu, Ni, Ag) and lithophile elements (e.g Mn) show marked deviations from linearity on a plot of logDi vs log[FeO]. More recent experiments show that linear behavior is confined to elements whose affinities for S and O are similar to those of Fe. In the case of elements more strongly lithophile than Fe (Ti, U, REE, Zr, Nb, Ta, Mn) a plot of logDi versus log[FeO] describes a U-shape with the element partitioning strongly into the sulfide at very low FeO and again at very high FeO content of the silicate melt. In contrast, strongly chalcophile elements (Cu, Ni, Ag) describe an n-shape on the plot of logD vs log[FeO]. The result is that lithophile elements such as Nb become more "chalcophile" than Cu at very low and very high FeO contents of the silicate melt. The reasons for this surprising behavior are firstly that, at very low FeO contents the silicate melt dissolves substantial amounts of sulfur, which drives down the activity of FeO and, from mass-action "pulls" the lihophile element into the sulfide. At high FeO contents of the silicate the sulfide itself starts to dissolve substantial amounts of oxygen and lithophile elements follow the oxygen into the sulfide. Given the principles which we have established, we are able to describe the patterns of chalcophile element behavior during partial melting and fractional crystallisation on Earth and also on bodies such as Mercury and Mars which are, respectively, strongly reduced relative to Earth and more oxidised than Earth.

  2. Assessing rare earth elements in quartz rich geological samples.

    PubMed

    Santoro, A; Thoss, V; Ribeiro Guevara, S; Urgast, D; Raab, A; Mastrolitti, S; Feldmann, J

    2016-01-01

    Sodium peroxide (Na2O2) fusion coupled to Inductively Coupled Plasma Tandem Mass Spectrometry (ICP-MS/MS) measurements was used to rapidly screen quartz-rich geological samples for rare earth element (REE) content. The method accuracy was checked with a geological reference material and Instrumental Neutron Activation Analysis (INAA) measurements. The used mass-mode combinations presented accurate results (only exception being (157)Gd in He gas mode) with recovery of the geological reference material QLO-1 between 80% and 98% (lower values for Lu, Nd and Sm) and in general comparable to INAA measurements. Low limits of detection for all elements were achieved, generally below 10 pg g(-1), as well as measurement repeatability below 15%. Overall, the Na2O2/ICP-MS/MS method proved to be a suitable lab-based method to quickly and accurately screen rock samples originating from quartz-rich geological areas for rare earth element content; particularly useful if checking commercial viability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Metal-silicate partitioning and the light element in the core (Invited)

    NASA Astrophysics Data System (ADS)

    Wood, B. J.; Wade, J.; Tuff, J.

    2009-12-01

    Most attempts to constrain the concentrations of “light” elements in the Earth’s core rely either on cosmochemical arguments or on arguments based on the densities and equations of state of Fe-alloys containing the element of concern. Despite its utility, the latter approach yields a wide range of permissible compositions and hence weak constraints. The major problem with the cosmochemical approach is that the abundances in the bulk Earth of all the candidate “light” elements- H, C, O, Si and S are highly uncertain because of their volatile behavior during planetary accretion. In contrast, refractory elements appear to be in approximately CI chondritic relative abundances in the Earth. This leads to the potential for using the partitioning of refractory siderophile elements between the mantle and core to constrain the concentrations of light elements in the core. Recent experimental metal-silicate partitioning data, coupled with mantle abundances of refractory siderophile elements (e.g. Wade and Wood, EPSL v.236, 78—95,2005; Kegler et. al. EPSL v.268, 28-40,2008) have shown that the core segregated from the mantle under high pressure conditions (~40 GPa). If a wide range of elements, from very siderophile, (e.g. Mo) through moderately (Ni, Co, W) to weakly siderophile (V, Cr, Nb, Si) are considered, the Earth also appears to have become more oxidized during accretion. Metal-silicate partitioning of some elements is also sensitive to the light element content of the metal. For example, Nb and W partitioning depend strongly on carbon, Mo on silicon and Cr on sulfur. Given the measured mantle abundances of the refractory elements, these observations enable the Si and C contents of the core to be constrained at ~5% and <2% respectively while partitioning is consistent with a cosmochemically-estimated S content of ~2%.

  4. Technological pretreatment of the synchysite non-oxidized ore

    NASA Astrophysics Data System (ADS)

    Munkhtsetseg, B.; Burmaa, G.

    2013-06-01

    Mongolia has rich deposits of rare, precious, and poly-metallic ores. Nowadays, it is important to research separation of rare earth elements oxides concentrates from the ores, analyze their unique physical chemical characteristics, and purified it. Our investigation on raw materials focuses on rare earth non-oxidized ores. Main mineral in this rock sample is Synchysite (LnCa(CO3)2F. We did technological and thermal pretreatment: direct sulphurization (H2SO4), sulphurization with subsequent roasting (800°C+H2SO4), sulphurization prior to roasting (H2SO4+650°C). Sulphurization method based on dissolution of rare earth mineral into sulfuric acid (93%) according to the reaction. The amount of rare earth element oxides is almost 10 times greater (29.16%) after direct sulphurization process, almost 8 times greater (21.14%) after sulphurization with subsequent roasting, and almost 20 times greater (44.62%) after sulphurization prior to roasting process. After those technological pretreatment raw material's micro elements Thorium and Uranium contents are reduced as follows: H2SO4>800°C+H2SO4>H2SO4+650°C. These results show that cerium group rare earth elements have very good solubility in water at +2°C temperature and decreasing micro elements content uranium and thorium good pretreatment condition is prior to roasting (H2SO4+650°C) of synchysite non-oxidized ore.

  5. Distribution and Geochemistry of Rare-Earth Elements in Rivers of Southern and Eastern Primorye (Far East of Russia)

    NASA Astrophysics Data System (ADS)

    Chudaev, O. V.; Bragin, I. V.; A, Kharitonova N.; Chelnokov, G. A.

    2016-03-01

    The distribution and geochemistry of rare earth elements (REE) in anthropogenic, technogenic and natural surface waters of southern and eastern Primorye, Far East of Russia, are presented in this study. The obtained results indicated that most of REE (up to 70%) were transported as suspended matter, ratio between dissolved and suspended forms varing from the source to the mouth of rivers. It is shown that all REE (except Ce) in the source of the rivers are predominantly presented in dissolved form, however, the content of light and heavy REE is different. Short-term enrichment of light rare earth elements (LREE) caused by REE-rich runoff from waste dumps and mining is neutralized by the increase in river flow rate. Rivers in urban areas are characterized by high content of LREE in dissolved form and very low in suspended one.

  6. Effects of rare earth and acid rain pollution on plant chloroplast ATP synthase and element contents at different growth stages.

    PubMed

    Zhang, Fan; Hu, Huiqing; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2018-03-01

    Combined rare earth and acid rain pollution has become a new environmental problem, seriously affecting plant survival. The effects of these two kinds of pollutants on plant photosynthesis have been reported, but the micro mechanisms are not very clear. In this research, we studied the effects of lanthanum [La(III), 0.08, 1.20 and 2.40 mM] and acid rain (pH value = 2.5, 3.5 and 4.5) on the ATPase activity and gene transcription level and the functional element contents in rice leaf chloroplasts. The results showed that the combined 0.08 mM La(III) and pH 4.5 acid rain increased the ATPase activity and gene transcription level as well as contents of some functional elements. But other combined treatments of acid rain and La(III) reduced the ATPase activity and gene transcription level as well as functional element contents. The change magnitude of the above indexes at rice booting stage was greater than that in seedling stage or grain filling stage. These results reveal that effects of La(III) and acid rain on ATPase activity and functional element contents in rice leaf chloroplasts are related to the combination of La(III) dose and acid rain intensity and the plant growth stage. In addition, the changes in the ATPase activity were related to ATPase gene transcription level. This study would provide a reference for understanding the microcosmic mechanism of rare earth and acid rain pollution on plant photosynthesis and contribute to evaluate the possible environmental risks associated with combined La(III) and acid rain pollution. The effects of La(III) and acid rain on activity and gene transcription level of rice chloroplast ATPase and contents of functional elements were different at different growth stages. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Rare earth element content of thermal fluids from Surprise Valley, California

    DOE Data Explorer

    Andrew Fowler

    2015-09-23

    Rare earth element measurements for thermal fluids from Surprise Valley, California. Samples were collected in acid washed HDPE bottles and acidified with concentrated trace element clean (Fisher Scientific) nitric acid. Samples were pre-concentratated by a factor of approximately 10 using chelating resin with and IDA functional group and measured on magnetic sector ICP-MS. Samples include Seyferth Hot Springs, Surprise Valley Resort Mineral Well, Leonard's Hot Spring, and Lake City Mud Volcano Boiling Spring.

  8. [Effects of rare earth compounds on human peripheral mononuclear cell telomerase and apoptosis].

    PubMed

    Yu, Li; Dai, Yu-Cheng; Yuan, Zhao-Kang; Li, Jie

    2004-07-01

    To study the effects of rare earth exposure on human telomerase and apoptosis of human peripheral mononuclear cells (PBMNs). Rare earth mine lot in Xunwu county, the biggest ion absorptive rare earth mine lot of China, was selected as the study site. Another village of Xunwu county, with comparable geological structure and social environment was selected as the control site. Thirty healthy adults were randomly selected from the study site as exposure group and another 30 healthy adults randomly selected from the control site as control group. The blood content of 15 rare earth elements, including La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, were determined by inductive coupled plasma-source mass spectrometry (ICP-MS). The total contents of rare earth elements in the blood were calculated. The TRAP and FCM assays were carried out to analyse the telomerase and apoptosis of human PBMNCs respectively. In the exposure group, the concentration of La, Ce, Dy and Y were significantly higher (P<0.001), and Pr, Nd, Sm, Gd and Yb were higher than those in the control group (P<0.05). The total content of rare earth in the blood of exposure group showed significant difference compared with control group (P<0.001). Telomerase activity in PBMNs of the exposure group was higher than that in the control group (P<0.05); there were 11 adults in the exposure group (30 adults) and 5 adults in control group (30 adults) showed positive telomerase activity. The average age of the exposure group was (38.69 +/- 8.02) years-old, while the control group was (40.45 +/- 9.02) years-old (P >0.05). It was found that there was a significant relationship between telomerase activity and the total content of rare earth elements (P <0.01). 3. The proportion of apoptosis was not different between the two groups (P >0.05), but the cells in the S-phase and G2-M phase were increased (P <0.01) in the exposed group. The telomerase activity of PBMNs in the rare earth elements exposed group was higher than that of the control group, and there is no effect on apoptotic rate of PBMNs, but may promote the diploid DNA replication, and increase the percentage of G2/M and S phase cells.

  9. Major, minor, trace and rare earth elements in sediments of the Bijagós archipelago, Guinea-Bissau.

    PubMed

    Carvalho, Lina; Figueira, Paula; Monteiro, Rui; Reis, Ana Teresa; Almeida, Joana; Catry, Teresa; Lourenço, Pedro Miguel; Catry, Paulo; Barbosa, Castro; Catry, Inês; Pereira, Eduarda; Granadeiro, José Pedro; Vale, Carlos

    2018-04-01

    Sixty sediment samples from four sites in the Bijagós archipelago were characterized for fine fraction, loss on ignition, major, minor and trace elemental composition (Al, Fe, Ca, Mg, Ti, P, Zr, Mn, Cr, Sr, Ba, B, V, Li, Zn, Ni, Pb, As, Co, U, Cu, Cs and Cd), and the elements of the La-Lu series. Element concentrations were largely explained by the Al content and the proportion of fine fraction content, with the exception of Ca and Sr. Sediments showed enhanced Ti, U, Cr, As and Cd concentrations with respect to estimated upper crust values, most likely mirroring a regional signature. Rare earth elements were in deficit relatively to the North American Shale Composite (NASC), mainly in coarser material. No pronounced Ce-anomaly was observed, while Eu-anomalies were positive in most analyzed sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Determination of rare earth elements concentration at different depth profile of Precambrian pegmatites using instrumental neutron activation analysis.

    PubMed

    Sadiq Aliyu, Abubakar; Musa, Yahaya; Liman, M S; Abba, Habu T; Chaanda, Mohammed S; Ngene, Nnamani C; Garba, N N

    2018-01-01

    The Keffi area hosts abundant pegmatite bodies as a result of the surrounding granitic intrusions. Keffi is part of areas that are geologically classified as North Central Basement Complex. Data on the mineralogy and mineralogical zonation of the Keffi pegmatite are scanty. Hence the need to understand the geology and mineralogical zonation of Keffi pegmatites especially at different depth profiles is relevant as a study of the elemental composition of the pegmatite is essential for the estimation of its economic viability. Here, the relative standardization method of instrumental neutron activation analysis (INAA) has been used to investigate the vertical deviations of the elemental concentrations of rare earth elements (REEs) at different depth profile of Keffi pegmatite. This study adopted the following metrics in investigating the vertical variations of REEs concentrations. Namely, the total contents of rare earth elements (∑REE); ratio of light to heavy rare earth elements (LREE/HREE), which defines the enrichment or depletion of REEs; europium anomaly (Eu/Sm); La/Lu ratio relative to chondritic meteorites. The study showed no significant variations in the total content of rare elements between the vertical depth profiles (100-250m). However, higher total concentrations of REEs (~ 92.65ppm) were recorded at the upper depth of the pegmatite and the europium anomaly was consistently negative at all the depth profiles suggesting that the Keffi pegmatite is enriched with light REEs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. EOS Reference Handbook 1999: A Guide to NASA's Earth Science Enterprise and the Earth Observing System

    NASA Technical Reports Server (NTRS)

    King, M. D. (Editor); Greenstone, R. (Editor)

    2000-01-01

    The content of this handbook includes Earth Science Enterprise; The Earth Observing System; EOS Data and Information System (EOSDIS); Data and Information Policy; Pathfinder Data Sets; Earth Science Information Partners and the Working Prototype-Federation; EOS Data Quality: Calibration and Validation; Education Programs; International Cooperation; Interagency Coordination; Mission Elements; EOS Instruments; EOS Interdisciplinary Science Investigations; and Points-of-Contact.

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

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  13. Water in Earth's mantle: Hydrogen analysis of mantle olivine, pyroxenes and garnet using the SIMS

    NASA Technical Reports Server (NTRS)

    Kurosawa, Masanori; Yurimoto, Hisayoshi; Sueno, Shigeho

    1993-01-01

    Hydrogen (or water) in the Earth's interior plays a key role in the evolution and dynamics of the planet. However, the abundance and the existence form of the hydrogen have scarcely been clear in practice. Hydrogen in the mantle was incorporated in the interior during the formation of the Earth. The incorporated hydrogen was hardly possible to concentrate locally inside the Earth considering its high mobility and high reactivity. The hydrogen, preferably, could be distributed homogeneously over the mantle and the core by the subsequent physical and chemical processes. Therefore, hydrogen in the mantle could be present in the form of trace hydrogen in nominally anhydrous mantle minerals. The hydrogen and the other trace elements in mantle olivines, orthopyroxenes, clinopyroxenes, and garnets were determined using secondary ion mass spectrometry (SIMS) for elucidating (1) the exact hydrogen contents, (2) the correlation between the hydrogen and the other trace elements, (3) the dependence of the hydrogen contents on the depth, and (4) the dependence of the whole rock water contents on the depth.

  14. Development of the "rare-earth" hypothesis to explain the reasons of geophagy in Teletskoye Lake are kudurs (Gorny Altai, Russia).

    PubMed

    Panichev, Alexander M; Seryodkin, Ivan V; Kalinkin, Yuri N; Makarevich, Raisa A; Stolyarova, Tatiana A; Sergievich, Alexander A; Khoroshikh, Pavel P

    2017-12-18

    The mineral and chemical composition of the liquid and lithogenous substances, consumed by the wild ungulate animals, at the kudurs of the Teletskoye Lake, Gorny Altai, Russia, was studied. It was investigated that all examined kudurits are argillous-aleurolitic and get in the interval from 1 to 100 μm with the predominance of the fraction 10 μm. By the mineral composition, the lithogenous kudurits present the quartz-feldspathic-hydromicaceous-chloritic mineral formations with the large content of the quartz particles (20-43%) and sodium-containing plagioclases (albite, 15-32 wt%). The lithogenous kudurits are the products of the reconstitution of the metamorphic cleaving stones as a result of the glacier abrasive effect, subsequent its aqueous deposits and then eolation in the subaerial conditions. The fontinal waters consumed at the kudurs are subsaline chloride-hydrocarbonate-sodium and sulphated-hydrocarbonate-calcium types. It essentially differs by the increased content of rare-earth elements in reference to the lake water. The acid (HCl, pH-1) extracts from the kudurits more actively extract calcium (10-35% of the gross contents; sodium extracts at the level of 1-3%). The most fluent in the microelements composition are Cu, Be, Sr, Co, Cd, Pb, Sc, Y and rare-earth elements. The transit of all these elements into the dissoluted form fluctuates about 10% from the gross contents. The reason of geophagy is related to tendency of herbivores to absorb mineralized subsoils enriched by the biologically accessible forms of rare-earth elements, arisen as a result of vital activity of specific microflora.

  15. Magma Ocean Depth and Oxygen Fugacity in the Early Earth--Implications for Biochemistry.

    PubMed

    Righter, Kevin

    2015-09-01

    A large class of elements, referred to as the siderophile (iron-loving) elements, in the Earth's mantle can be explained by an early deep magma ocean on the early Earth in which the mantle equilibrated with metallic liquid (core liquid). This stage would have affected the distribution of some of the classic volatile elements that are also essential ingredients for life and biochemistry - H, C, S, and N. Estimates are made of the H, C, S, and N contents of Earth's early mantle after core formation, considering the effects of variable temperature, pressure, oxygen fugacity, and composition on their partitioning. Assessment is made of whether additional, exogenous, sources are required to explain the observed mantle concentrations, and areas are identified where additional data and experimentation would lead to an improved understanding of this phase of Earth's history.

  16. Concentrations and health risk assessment of rare earth elements in vegetables from mining area in Shandong, China.

    PubMed

    Zhuang, Maoqiang; Zhao, Jinshan; Li, Suyun; Liu, Danru; Wang, Kebo; Xiao, Peirui; Yu, Lianlong; Jiang, Ying; Song, Jian; Zhou, Jingyang; Wang, Liansen; Chu, Zunhua

    2017-02-01

    To investigate the concentrations of rare earth elements in vegetables and assess human health risk through vegetable consumption, a total of 301 vegetable samples were collected from mining area and control area in Shandong, China. The contents of 14 rare earth elements were determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The total rare earth elements in vegetables from mining and control areas were 94.08 μg kg -1 and 38.67 μg kg -1 , respectively, and the difference was statistically significant (p < 0.05). The leaf vegetable had the highest rare earth elements concentration (984.24 μg kg -1 and 81.24 μg kg -1 for mining and control areas, respectively) and gourd vegetable had the lowest rare earth elements concentration (37.34 μg kg -1 and 24.63 μg kg -1 for mining and control areas, respectively). For both areas, the rare earth elements concentration in vegetables declined in the order of leaf vegetable > taproot vegetable > alliaceous vegetable > gourd vegetable. The rare earth elements distribution patterns for both areas were characterized by enrichment of light rare earth elements. The health risk assessment demonstrated that the estimated daily intakes (0.69 μg kg -1 d -1 and 0.28 μg kg -1 d -1 for mining and control areas, respectively) of rare earth elements through vegetable consumption were significantly lower than the acceptable daily intake (70 μg kg -1 d -1 ). The damage to adults can be neglected, but more attention should be paid to the effects of continuous exposure to low levels of rare earth elements on children. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Fractionation of rare-earth elements in allanite and monazite as related to geology of the Mt. Wheeler mine area, Nevada

    USGS Publications Warehouse

    Lee, D.E.; Bastron, H.

    1967-01-01

    Rare-earth contents of 20 allanites and 13 monazites, accessory minerals from a restricted outcrop area of intrusive granitic rocks, are reported. A quantity called sigma (??), which is the sum of the atomic percentages of La, Ce and Pr, is used as an index of composition with respect to the rare-earth elements. Values of sigma vary from 61.3 to 80.9 at.% for these allanites and monazites, representing an appreciable range of composition in terms of the rare-earth elements. Degree of fractionation of rare earths varies directly with CaO content of the granitic rocks, which in turn depends largely on proximity of limestone. Four xenoliths included in the study suggest that spotty mosaic equilibria are superimposed on the regional gradients and that locally the degree of fractionation of rare earths responds to whole rock composition over distances of a few yards or less. The chemistry of the granitic rocks under study appears to be similar in some respects to that of alkalio rocks and carbonatites. Allanites from the most calcium-rich rocks show a pronounced concentration of the most basic rare earths, and whole-rock concentrations of such rare constituents as total cerium earths, Zr, F, Ti, Ba and Sr increase sympathetically with whole-rock calcium. The explanation for the concentration gradients observed in this chemical system must involve assimilation more than magmatic differentiation. ?? 1967.

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

    PubMed

    Protano, G; Riccobono, F

    2002-01-01

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

  19. Origin and mixing timescale of Earth's late veneer

    NASA Astrophysics Data System (ADS)

    Prescher, C.; Allu Peddinti, D.; Bell, E. A.; Bello, L.; Cernok, A.; Ghosh, N.; Tucker, J.; Wielicki, M. M.; Zahnle, K. J.

    2012-12-01

    Experimental studies on the partitioning behavior of highly siderophile elements (HSE) between silicate and metallic melts imply that the Earth's mantle should have been highly depleted in these elements by core formation in an early magma ocean. However, present HSE contents of the Earth's mantle are ~3 orders of magnitude higher than that expected by experiments. The apparent over-abundance of HSE has commonly been explained by the addition of meteoritic material in the "late veneer" which describes the exogenous mass addition following the moon forming impact and concluding with the late heavy bombardment at ~3.8-3.9 Ga. The strongest evidence for this theory is that the platinum group element (PGE) contents in today's mantle are present in chondritic relative abundances, as opposed to a fractionated pattern expected with metal-silicate partitioning. Archean komatiites indicate that the PGE content of the Earth's mantle increased from about half their present abundances at 3.5 Ga to their present abundances at 2.9 Ga. This secular increase in PGE content suggests a progressive mixing of the late veneer material into the Earth's mantle. However, this time scale also implies that the whole mantle was relatively well mixed by 2.9 Ga. We use a compilation of existing isotopic and trace element data in order to constrain the origin and composition of the late veneer. We use PGE abundances, W abundances and W isotopic compositions in chondritic meteorites and the primitive upper mantle to compute the amount of mass delivered during the late veneer and find the late veneer mass to be ~0.6 % the mass of the bulk silicate Earth (consistent with earlier estimates). We also use the 187Re-187Os and 190Pt-186Os systems to constrain the composition and timing of delivery of the impacting population. We model the efficiency of mantle mixing in this time frame by using 3-dimensional numerical geodynamical simulations and geochemical constraints. Initial parameters include the amount of mass delivered in the late veneer and the Archean internal heating which is at least 4 times higher than the present values, due to the higher abundance of radioactive elements. Another important parameter is the mechanism of mass addition to the Earth. We test three end-member scenarios: (1) a single very large impactor accounting for the entire mass addition, (2) sprinkling of a large number of small impactors over the whole Earth which then mix into the mantle, or (3) by using a size/frequency distribution estimated from the lunar cratering record and corrected for the difference in gravitational cross section of the Earth and the Moon. This project results from collaborations begun at the CIDER II workshop held at KITP, UCSB, 2012.

  20. Effect of CeO2 on TiC Morphology in Ni-Based Composite Coating

    NASA Astrophysics Data System (ADS)

    Cai, Yangchuan; Luo, Zhen; Chen, Yao

    2018-03-01

    The TiC/Ni composite coating with different content of CeO2 was fabricated on the Cr12MoV steel by laser cladding. The microstructure of cladding layers with the different content of CeO2 from the bottom to the surface is columnar crystal, cellular crystal, and equiaxed crystal. When the content of CeO2 is 0 %, the cladding layer has a coarse and nonuniform microstructure and TiC particles gathering in the cladding layer, and then the wear resistance was reduced. Appropriate rare-earth elements refined and homogenised the microstructure and enhanced the content of carbides, precipitated TiC particles and original TiC particles were spheroidised and refined, the wear resistance of the cladding layer was improved significantly. Excessive rare-earth elements polluted the grain boundaries and made the excessive burning loss of TiC particles that reduced the wear resistance of the cladding layer.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  2. Trace element geochemistry of Archean volcanic rocks

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mattigod, Shas V.

    2003-08-01

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

  4. Rare earth elements in intertidal sediments of Bohai Bay, China: concentration, fractionation and the influence of sediment texture.

    PubMed

    Zhang, Yong; Gao, Xuelu; Arthur Chen, Chen-Tung

    2014-07-01

    Surface sediments from intertidal Bohai Bay were assessed using a four-step sequential extraction procedure to determine their concentrations of rare earth elements (REEs) and the chemical forms in which those elements were present. The normalized ratios La/Gd and La/Yb showed that LREE contents were not significantly higher than the middle REEs or HREE contents. A negative Ce anomaly and positive Eu were observed in sand and silty sand sediments, whereas no significant Ce or Eu anomaly was found in clayey silt sediments. Residual fraction of REEs accounted for the majority of their total concentrations. Middle REEs were more easily leached than other REEs, especially in clayey silt sediment. REEs contents in the surface sediment from the intertidal Bohai Sea were consistent with data from the upper continental crust and China shallow sea sediments, indicating that they were generally unaffected by heavily anthropogenic effects from adjacent areas. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Rare earth element contents and multiple mantle sources of the transform-related Mount Edgecumbe basalts, southeastern Alaska

    USGS Publications Warehouse

    Riehle, J.R.; Budahn, J.R.; Lanphere, M.A.; Brew, D.A.

    1994-01-01

    Pleistocene basalt of the Mount Edgecumbe volcanic field (MEF) is subdivided into a plagioclase type and an olivine type. Th/La ratios of plagioclase basalt are similar to those of mid-ocean-ridge basalt (MORB), whereas those of olivine basalt are of continental affinity. Rare earth element (REE) contents of the olivine basalt, which resemble those of transitional MORB, are modelled by 10-15% partial melting of fertile spinel-plagioclase lherzolite followed by removal of 8-13% olivine. It is concluded that olivine basalt originated in subcontinental spinel lherzolite and that plagioclase basalt may have originated in suboceanic lithosphere of the Pacific plate. -from Authors

  6. How Irreversible Heat Transport Processes Drive Earth's Interdependent Thermal, Structural, and Chemical Evolution Providing a Strongly Heterogeneous, Layered Mantle

    NASA Astrophysics Data System (ADS)

    Hofmeister, A.; Criss, R. E.

    2013-12-01

    Because magmatism conveys radioactive isotopes plus latent heat rapidly upwards while advecting heat, this process links and controls the thermal and chemical evolution of Earth. We present evidence that the lower mantle-upper mantle boundary is a profound chemical discontinuity, leading to observed heterogeneities in the outermost layers that can be directly sampled, and construct an alternative view of Earth's internal workings. Earth's beginning involved cooling via explosive outgassing of substantial ice (mainly CO) buried with dust during accretion. High carbon content is expected from Solar abundances and ice in comets. Reaction of CO with metal provided a carbide-rich core while converting MgSiO3 to olivine via oxidizing reactions. Because thermodynamic law (and buoyancy of hot particles) indicates that primordial heat from gravitational segregation is neither large nor carried downwards, whereas differentiation forced radioactive elements upwards, formation of the core and lower mantle greatly cooled the Earth. Reference conductive geotherms, calculated using accurate and new thermal diffusivity data, require that heat-producing elements are sequestered above 670 km which limits convection to the upper mantle. These irreversible beginnings limit secular cooling to radioactive wind-down, permiting deduction of Earth's inventory of heat-producing elements from today's heat flux. Coupling our estimate for heat producing elements with meteoritic data indicates that Earth's oxide content has been underestimated. Density sorting segregated a Si-rich, peridotitic upper mantle from a refractory, oxide lower mantle with high Ca, Al and Ti contents, consistent with diamond inclusion mineralogy. Early and rapid differentiation means that internal temperatures have long been buffered by freezing of the inner core, allowing survival of crust as old as ca.4 Ga. Magmatism remains important. Melt escaping though stress-induced fractures in the rigid lithosphere imparts a lateral component and preferred direction to upper mantle circulation. Mid-ocean magma production over ca. 4 Ga has deposited a slab volume at 670 km that is equivalent to the transition zone, thereby continuing differentiation by creating a late-stage chemical discontinuity near 400 km. This ongoing process has generated the observed lateral and vertical heterogeneity above 670 km.

  7. A volatile topic: Parsing out the details of Earth's formation through experimental metal-silicate partitioning of volatile and moderately volatile elements

    NASA Astrophysics Data System (ADS)

    Mahan, B. M.; Siebert, J.; Blanchard, I.; Badro, J.; Sossi, P.; Moynier, F.

    2017-12-01

    Volatile and moderately volatile elements display different volatilities and siderophilities, as well as varying sensitivity to thermodynamic controls (X, P, T, fO2) during metal-silicate differentiation. The experimental determination of the metal-silicate partitioning of these elements permits us to evaluate processes controlling the distribution of these elements in Earth. In this work, we have combined metal-silicate partitioning data and results for S, Sn, Zn and Cu, and input these characterizations into Earth formation models. Model parameters such as source material, timing of volatile delivery, fO2 path, and degree of impactor equilibration were varied to encompass an array of possible formation scenarios. These models were then assessed to discern plausible sets of conditions that can produce current observed element-to-element ratios (e.g. S/Zn) in the Earth's present-day mantle, while also satisfying current estimates on the S content of the core, at no more than 2 wt%. The results of our models indicate two modes of accretion that can maintain chondritic element-to-element ratios for the bulk Earth and can arrive at present-day mantle abundances of these elements. The first mode requires the late addition of Earth's entire inventory of these elements (assuming a CI-chondritic composition) and late-stage accretion that is marked by partial equilibration of large impactors. The second, possibly more intuitive mode, requires that Earth accreted - at least initially - from volatile poor material preferentially depleted in S relative to Sn, Zn, and Cu. From a chemical standpoint, this source material is most similar to type I chondrule rich (and S poor) materials (Hewins and Herzberg, 1996; Mahan et al., 2017; Amsellem et al., 2017), such as the metal-bearing carbonaceous chondrites.

  8. Effect of Solution Treatment on Microstructure and Properties of Gd - AZ91 Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Li, Yao; Wang, Huiling

    2018-01-01

    In this paper, the Gd-AZ91 alloy was manufactured by adding rare earth element Gd in AZ91 magnesium alloy. The effects of solution treatment on the microstructures of rare earth elements Gd were investigated by means of optical microscopy, scanning electron microscopy, X-ray diffraction analysis and equipment for testing mechanical properties. The experimental results show that the addition of rare earth element Gd in AZ91 magnesium alloy can refine the alloy grain, turn β-Mg17Al12 phase into a discontinuous network or point structure, and produce granular compound Al2Gd in the alloy; when solution temperature is about 380 °C, the alloy structure is the best, the tensile strength of the alloy is the largest with the value larger than 250Mpa; when the solution temperature exceeds 380 °C, the alloy structure is coarsened and the mechanical properties of the alloy are reduced. With the increase of rare earth element Gd content, the tensile strength of the alloy shows a tendency to increase gradually, which Indicates that the addition of a certain amount of rare earth elements Gd can improve the plasticity of the alloy.

  9. Rare earth elements upon assessment of reasons of the geophagy in Sikhote-Alin region (Russian Federation), Africa and other world regions.

    PubMed

    Panichev, Alexander M; Popov, Vladimir K; Chekryzhov, Igor Yu; Seryodkin, Ivan V; Stolyarova, Tatiana A; Zakusin, Sergey V; Sergievich, Alexandr A; Khoroshikh, Pavel P

    2016-12-01

    Rocks eaten by wild animals on the Bolshoy Shanduyskiy kudur in the Sikhote-Alin region (Russian Federation) are zeolite-clay mineral complexes-products of weathering of zeolitized vitric tuffs of rhyolite composition, deposited in aqueous medium within the volcanic caldera of about 55 million years ago. By composition of rock-forming oxides, the tuffs refer to high-potassium calc-alkaline series. In trace elements of most favorite kudurites of the Bolshoy Shanduyskiy kudur, there are significantly increased contents of most of rare earth elements (2-5 times in comparison with surrounding rocks). The results of our analysis of geological and geochemical data on kudurs and kudurites in another part of the Sikhote-Alin, as well as on other regions of the world (particularly, in Africa and Indonesia), taking into account new data on the prevalence of rare earth elements in living matter and their medical and biological properties, enable us to consider the version of causal connection of the geophagy with rare earth elements.

  10. Constraining the Depth of a Martian Magma Ocean through Metal-Silicate Partitioning Experiments: The Role of Different Datasets and the Range of Pressure and Temperature Conditions

    NASA Technical Reports Server (NTRS)

    Righter, K.; Chabot, N.L.

    2009-01-01

    Mars accretion is known to be fast compared to Earth. Basaltic samples provide a probe into the interior and allow reconstruction of siderophile element contents of the mantle. These estimates can be used to estimate conditions of core formation, as for Earth. Although many assume that Mars went through a magma ocean stage, and possibly even complete melting, the siderophile element content of Mars mantle is consistent with relatively low pressure and temperature (PT) conditions, implying only shallow melting, near 7 GPa and 2073 K. This is a pressure range where some have proposed a change in siderophile element partitioning behavior. We will examine the databases used for parameterization and split them into a low and higher pressure regime to see if the methods used to reach this conclusion agree for the two sets of data.

  11. A chemical-spectrochemical method for the determination of rare earth elements and thorium in cerium minerals

    USGS Publications Warehouse

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

    1954-01-01

    In a combined chemical-spectrochemical procedure for quantitatively determining rare earth elements in cerium minerals, cerium is determined volumetrically, a total rare earths plus thoria precipitate is separated chemically, the ceria content of the precipitate is raised to 80??0 percent by adding pure ceria, and the resulting mixture is analyzed for lanthanum, praseodymium, neodymium, samarium, gadolinium, yttrium, and thorium spectrochemically by means of the d.c. carbon arc. Spectral lines of singly ionized cerium are used as internal standard lines in the spectrochemical determination which is patterned after Fassel's procedure [1]. Results of testing the method with synthetic mixtures of rare earths and with samples of chemically analyzed cerium minerals show that the coefficient of variation for a quadruplicate determination of any element does not exceed 5??0 (excepting yttrium at concentrations less than 1 percent) and that the method is free of serious systematic error. ?? 1954.

  12. Accumulation of rare earth elements in human bone within the lifespan.

    PubMed

    Zaichick, Sofia; Zaichick, Vladimir; Karandashev, Vasilii; Nosenko, Sergey

    2011-02-01

    For the first time, the contents of rare earth elements (REEs) in a rib bone of a healthy human were determined. The mean value of the contents of Ce, Dy, Er, Gd, La, Nd, Pr, Sm, Tb, and Yb (10 elements out of 17 total REEs), as well as the upper limit of means for Ho, Lu, Tm, and Y (4 elements) were measured in the rib bone tissue of 38 females and 42 males (15 to 55 years old) using inductively coupled plasma mass spectrometry (ICP-MS). We found age-related accumulation of REEs in the bone tissue of healthy individuals who lived in a non-industrial region. It was calculated that during a lifespan the content of REEs in a skeleton of non-industrial region residents may increase by one to two orders of magnitude. Using our results as indicative normal values and published data we estimated relative Gd accumulation in the bone tissue of patients according to magnetic resonance imaging with contrast agent and La accumulation in the bone tissue of patients receiving hemodialysis after treatment with lanthanum carbonate as a phosphate binder. It was shown that after such procedures contents of Gd and La in the bone tissue of patients are two to three orders of magnitude higher than normal levels. In our opinion, REEs incorporation may affect bone quality and health similar to other potentially toxic trace metals. The impact of elevated REEs content on bone physiology, biochemistry and morphology requires further investigation.

  13. Composition of the earth's upper mantle. II - Volatile trace elements in ultramafic xenoliths

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    Radiochemical neutron activation analysis was used to determine the nine volatile elements Ag, Bi, Cd, In, Sb, Se, Te, Tl, and Zn in 19 ultramafic rocks, consisting mainly of spinel and garnet lherzolites. A sheared garnet lherzolite, PHN 1611, may approximate undepleted mantle material and tends to have a higher volatile element content than the depleted mantle material represented by spinel lherzolites. Comparisons of continental basalts with PHN 1611 and of oceanic ridge basalts with spinel lherzolites show similar basalt: source material partition factors for eight of the nine volatile elements, Sb being the exception. The strong depletion of Te and Se in the mantle, relative to lithophile elements of similar volatility, suggests that 97% of the earth's S, Se and Te may be in the outer core.

  14. Constraining the Depth of the Martian Magma Ocean during Core Formation using Element Partitioning

    NASA Astrophysics Data System (ADS)

    Wijbrans, Ineke; Tronche, Elodie; van Westrenen, Wim

    2010-05-01

    The depth of a planetary magma ocean places first order constraints on the thermal state of a young planet. For the Earth, the depth of the magma ocean is mostly constrained by the pressure-temperature conditions at which Fe-rich metal last equilibrated with the bulk silicate Earth (BSE). These equilibration conditions are thought to correspond to the conditions at the terrestrial magma ocean floor, as this is where the metal ponds before sinking to the core. This depth is estimated by combining the BSE contents of siderophile (iron-loving) elements with metal-silicate partition coefficients (D) at high temperatures and pressures [e.g. 1]. The extent and depth of a magma ocean on Mars are hotly debated. In the case of Mars, the sulphur content of the core is significantly higher than for Earth (10-16 wt% sulphur [2]). The presence of sulphur has been shown to have an effect on the metal-silicate partitioning of some siderophile elements [3], but the current data set is insufficient to be of use for direct application to Martian conditions. We have started an experimental programme to constrain siderophile element partition coefficients for Ni and Co between metal and silicate as a function of temperature, pressure and sulphur content in the metal-alloy. For the silicate composition we used a newly proposed bulk silicate Mars (BSM) [4]. We chose the above-mentioned siderophile elements because their BSM concentrations are reasonably known from studies of Martian meteorites. Our aim is to derive new constraints on the depth of the Martian magma ocean and the chemistry accompanying Martian core formation. Experimental methods: The starting material consisted of a 1:1 mixture of silicate glass + quench crystals in the FeO-CaO-MgO-Al2O3-SiO2 (FCMAS) system with a composition based on [4], and metal consisting of FeS, Fe, Ni, Co, FeP3. Four different metal compositions were used with sulphur contents of 0, 5, 15 and 25wt% respectively. Experiments were made in an end-loaded piston-cylinder using graphite-lined Pt capsules. Experiments were performed at 1, 2 and 3 GPa, and at temperatures of 1600 and 1650 °C, for 5hrs. Electron microprobe was used to determine the concentration of major and minor elements in each phase. Results: Preliminary results show that the sulfur content has an effect on the siderophile element partitioning, even within this small range of pressures and temperatures. With these experiments made with realistic conditions for a Martian magma ocean, we will present a new parameterization of metal-silicate D (Ni and Co) depending on pressure, temperature and sulfur content. References: [1] Righter (2003) Ann. Rev. Earth Planet. Sci. 31, 135-174 [2] Schubert (1990) JGR 95, 14095-14104. [3] Jana and Walker (1997) GCA 61, 5255-5277. [4] Khan and Connolly (2008) JGR, 113, E07003.

  15. Thorium: Issues and prospects in Malaysia

    NASA Astrophysics Data System (ADS)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman; Bahri, Che Nor Aniza Che Zainul

    2015-04-01

    In Malaysia, thorium exists in minerals and rare earth elements production residue. The average range of thorium content in Malaysian monazite and xenotime minerals was found about 70,000 and 15,000 ppm respectively. About 2,636 tonnes of Malaysian monazite was produced for a period of 5 years (2006-2010) and based on the above data, it can be estimated that Malaysian monazite contains about 184.5 tonnes of thorium. Although thorium can become a major radiological problem to our environment, but with the significant deposit of thorium in Malaysian monazite, it has a prospect as a future alternative fuel in nuclear technology. This paper will discuss the thorium issues in Malaysia especially its long term radiological risks to public health and environment at storage and disposal stages, the prospect of exploring and producing high purity thorium from our rare earth elements minerals for future thorium based reactor. This paper also highlights the holistic approach in thorium recovery from Malaysian rare earth element production residue to reduce its radioactivity and extraction of thorium and rare earth elements from the minerals with minimum radiological impact to health and environment.

  16. Trace Elemental Imaging of Rare Earth Elements Discriminates Tissues at Microscale in Flat Fossils

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-01-01

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

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

    PubMed

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

    2015-11-01

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

  19. Statistical Constraints from Siderophile Elements on Earth's Accretion, Differentiation, and Initial Core Stratification

    NASA Astrophysics Data System (ADS)

    O'Rourke, J. G.; Stevenson, D. J.

    2015-12-01

    Abundances of siderophile elements in the primitive mantle constrain the conditions of Earth's core/mantle differentiation. Core growth occurred as Earth accreted from collisions between planetesimals and larger embryos of unknown original provenance, so geochemistry is directly related to the overall dynamics of Solar System formation. Recent studies claim that only certain conditions of equilibration (pressure, temperature, and oxygen fugacity) during core formation can reproduce the available data. Typical analyses, however, only consider the effects of varying a few out of tens of free parameters in continuous core formation models. Here we describe the Markov chain Monte Carlo method, which simultaneously incorporates the large uncertainties on Earth's composition and the parameterizations that describe elemental partitioning between metal and silicate. This Bayesian technique is vastly more computationally efficient than a simple grid search and is well suited to models of planetary accretion that involve a plethora of variables. In contrast to previous work, we find that analyses of siderophile elements alone cannot yield a unique scenario for Earth's accretion. Our models predict a wide range of possible light element contents for the core, encompassing all combinations permitted by seismology and mineral physics. Specifically, we are agnostic between silicon and oxygen as the dominant light element, and the addition of carbon or sulfur is also permissible but not well constrained. Redox conditions may have remained roughly constant during Earth's accretion or relatively oxygen-rich material could have been incorporated before reduced embryos. Pressures and temperatures of equilibration, likewise, may only increase slowly throughout accretion. Therefore, we do not necessarily expect a thick (>500 km), compositionally stratified layer that is stable against convection to develop at the top of the core of Earth (or, by analogy, Venus). A thinner stable layer might inhibit the initialization of the dynamo.

  20. The lead isotopic age of the Earth can be explained by core formation alone.

    PubMed

    Wood, Bernard J; Halliday, Alex N

    2010-06-10

    The meaning of the age of the Earth defined by lead isotopes has long been unclear. Recently it has been proposed that the age of the Earth deduced from lead isotopes reflects volatile loss to space at the time of the Moon-forming giant impact rather than partitioning into metallic liquids during protracted core formation. Here we show that lead partitioning into liquid iron depends strongly on carbon content and that, given a content of approximately 0.2% carbon, experimental and isotopic data both provide evidence of strong partitioning of lead into the core throughout the Earth's accretion. Earlier conclusions that lead is weakly partitioned into iron arose from the use of carbon-saturated (about 5% C) iron alloys. The lead isotopic age of the Earth is therefore consistent with partitioning into the core and with no significant late losses of moderately volatile elements to space during the giant impact.

  1. What Would It Take for an Atmospheric Neutrino Detector to Constrain the Hydrogen Content of the Earth's Core ?

    NASA Astrophysics Data System (ADS)

    Bourret, S.; Coelho, J. A. B.; Kaminski, E. C.; Van Elewyck, V.

    2017-12-01

    The difference between PREM density and seismic profiles in the Earth's core and the values for pure iron and iron-nickel alloys inferred from high pressure/high temperature experiments and ab initio calculations requires the presence of a few wt% of light elements. The nature and amount of these light elements (O, Si, S, H, C...) remains controversial. Recent studies have renewed the interest in H. It is the most abundant element in the nebula and can be easily dissolved in iron in the early stages of Earth's evolution. 1 to 2 wt% of H could explain the difference between PREM and pure iron. However, current geophysical methods alone cannot settle the debate between H and the other candidate elements. Neutrino oscillation tomography using atmospheric neutrinos opens an avenue to collect independent data on Earth's core composition. This method exploits the quantum phenomenon of neutrino flavour oscillations, which depends on the electron density along the path of the neutrino through the Earth. The combination of a neutrino-based measurement of the electron density with the PREM mass density profile constrains the average proton-to-nucleon ratio of the medium (Z/A). Since this parameter varies among chemical elements, e.g. 0.466 for Fe and 1 for H, this technique has the potential to provide unprecedented insights into the chemical composition of the core, and in particular its hydrogen content. Performing such a measurement requires large-size detectors with good efficiency in the relevant energy range and precise determination of the neutrino energy, arrival direction, and flavour. Considering a generic but realistic model of detector response, we quantify the influence of various detector performance indicators on the sensitivity to the average Z/A in the core. We further evaluate the impact of systematic uncertainties, such as those related to the physical model for neutrino oscillations and the incoming flux of atmospheric neutrinos. We consider specific examples of the next-generation detectors planned to start operating within the decade: ORCA, PINGU, Hyper-Kamiokande, and DUNE. We also identify the most crucial improvements required to reach a measurement of the H content of the core with a precision better than 1 wt%.

  2. What Should the FeO Content of a Terrestrial Planet Be?

    NASA Technical Reports Server (NTRS)

    Jones, John H.

    2013-01-01

    Basalts from the Earth, the Moon, Mars, and Vesta are strongly depleted in elements that prefer to reside in the metallic state (siderophile elements). Therefore, it is believed that all these bodies have metallic cores. We do not yet have siderophile element analyses of venusian or mercurian basalts, but we assume that Venus, too, as a terrestrial planet, has a metallic core. For the Earth, Moon, Mercury, and Mars, the moments-of-inertia of these bodies are consistent with metallic cores of various sizes. Because Venus rotates so slowly, it may be difficult to determine the moment-of-inertia of Venus in order to confirm this assumption. However, despite many possible complexities, it seems likely that most of the major and minor terrestrial planets have experienced some sort of metal/silicate equilibration, and we will use this as a boundary condition. One immediate contrast between the Earth and Moon is the difference in FeO content between lunar and terrestrial basalts. Both bodies presumably formed near 1 AU and formed from the same feeding zone of planetesimals, judging by their oxygen isotopes [13]. If, for example, the Moon formed from the Earth by a giant impact, then this event must have occurred before high-pressure equilibria had the opportunity to deplete the Earth s mantle in FeO. Alternatively, the bulk silicate Moon may be dominated by material from the impactor. Regardless, it would be useful to know the pressures where FeO incorporation into a metallic core is not of interest. If the Giant Impact hypothesis is correct, this should set an upper limit for the size of the proto-Earth at the time of the impact.

  3. Levels of platinum group elements and rare-earth elements in wild mushroom species growing in Poland.

    PubMed

    Mleczek, Mirosław; Niedzielski, Przemysław; Kalač, Pavel; Siwulski, Marek; Rzymski, Piotr; Gąsecka, Monika

    2016-01-01

    Due to limited data-describing abilities of mushrooms to accumulate platinum group elements (PGEs) and rare-earth elements (REEs), the aim of this study was to determine, by inductively coupled plasma optical emission spectrometry followed by microwave-assisted sample digestion by nitric acid, the content of these elements in 20 mushroom species (10 above ground and 10 growing on wood), mostly edible, collected near a busy trunk road. The highest content of PGEs in above-ground mushroom species was observed in Lepista gilva and Suillus bovinus fruit bodies (0.38 ± 0.05 and 0.37 ± 0.03 mg kg(-1) DW, respectively), while in mushrooms growing on wood, the highest content was observed in Pleurotus ostreatus (0.35 ± 0.04 mg kg(-1) DW). The mean content of PGEs for both these groups was 0.23 ± 0.08 and 0.26 ± 0.07 mg kg(-1) DW, respectively. The highest content of REEs in Suillus luteus and Tricholoma equestra was 5.03 ± 0.50 and 2.18 ± 0.56 mg kg(-1) DW, respectively, but within mushrooms growing on wood in Ganoderma applanatum fruiting bodies it was 4.19 ± 0.78 mg kg(-1) DW. Mean contents of REEs were 1.39 ± 1.21 and 1.61 ± 0.97 mg kg(-1) DW in above-ground species and species growing on wood, respectively. Generally, the group of mushroom species growing on wood was capable of slightly higher accumulation of both REEs and PGEs. No limits have been established for both the groups until now.

  4. The surface sediment types and their rare earth element characteristics from the continental shelf of the northern south China sea

    NASA Astrophysics Data System (ADS)

    Wang, Shuhong; Zhang, Nan; Chen, Han; Li, Liang; Yan, Wen

    2014-10-01

    The grain size as well as some major and trace elements, including rare earth element (REE), for 273 surface sediment samples collected from the continental shelf of the northern South China Sea were analyzed in this study. The sediment types are mainly sandy silt and silt, making up 60% of the whole samples, and secondly are mud, sandy mud, muddy sand and silty sand, making up 28% of the whole samples, based on grain-size in which the Folk's classification was used. The total REE content (ΣREE) show a wide variation from 21 ppm to 244 ppm with an average value of 155 ppm, which similar to the average ΣREE of the China loess, but much different from that in deep-sea clay, showing a significant terrigenous succession. The REE contents in different sediment types vary greatly, mainly enriching in silt, sandy silt, mud and sandy mud. The REE distribution contours parallel to the coastal, presenting like strips and their contents gradually reduce with increasing distance from the coast. The high content of the western Pearl River Mouth, Shang/Xiachuan Islands and Hailing Bay might be regarded to the coastal current developed from the east to the west along to the Pearl River Mouth in the northern South China Sea. But the chondrite-normalized REE patterns in various sediment types have no difference, basically same as those of coastal rivers and upper crust. They all show relative enrichments in light rare earth element (LREE), noticeable negative Eu anomaly and no Ce anomaly, indicating that those sediments are terrigenous sediments and from the same source region. Further analysis suggest that the sedimentary environment in the study area is relatively stable and granite widely distributed in the South China mainland is the main source of REE, which are transported mainly by the Pearl River. The late diagenesis has little effect on the REE.

  5. Application of solid phase extraction procedures for rare earth elements determination in environmental samples.

    PubMed

    Pyrzynska, Krystyna; Kubiak, Anna; Wysocka, Irena

    2016-07-01

    Determination of rare earth elements in environmental samples requires often pre-concentration and separation step due to a low metal content and high concentration of the interfering matrix components. A solid phase extraction technique with different kind of solid sorbents offers a high enrichment factor, rapid phase separation and the possibility of its combination with various detection techniques used either in on-line or off-line mode. The recent developments in this area published over the last five years are presented and discussed in this paper. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Phytoextraction of rare earth elements in herbaceous plant species growing close to roads.

    PubMed

    Mikołajczak, Patrycja; Borowiak, Klaudia; Niedzielski, Przemysław

    2017-06-01

    The aim of study was to determine the phytoextraction of rare earth elements (REEs) to roots, stems and leaves of five herbaceous plant species (Achillea millefolium L., Artemisia vulgaris L., Papaver rhoeas L., Taraxacum officinale AND Tripleurospermum inodorum), growing in four areas located in close proximity to a road with varied traffic intensity. Additionally, the relationship between road traffic intensity, REE concentration in soil and the content of these elements in plant organs was estimated. A. vulgaris and P. rhoeas were able to effectively transport REEs in their leaves, independently of area collection. The highest content of REEs was observed in P. rhoeas leaves and T. inodorum roots. Generally, HREEs were accumulated in P. rhoeas roots and leaves and also in the stems of T. inodorum and T. officinale, whereas LREEs were accumulated in T. inodorum roots and T. officinale stems. It is worth underlining that there was a clear relationship between road traffic intensity and REE, HREE and LREE concentration in soil. No positive correlation was found between the concentration of these elements in soil and their content in plants, with the exception of T. officinale. An effective transport of REEs from the root system to leaves was observed, what points to the possible ability of some of the tested plant species to remove REEs from soils near roads.

  7. Rare earth elements concentration in mushroom cultivation substrates affects the production process and fruit-bodies content of Pleurotus ostreatus and Cyclocybe cylindracea.

    PubMed

    Koutrotsios, Georgios; Danezis, Georgios P; Georgiou, Constantinos A; Zervakis, Georgios I

    2018-04-20

    Concentrations of 16 rare earth elements (REEs) and two actinides were determined for the first time both in cultivated mushrooms and in their production substrates by inductively coupled plasma mass spectroscopy. Moreover, the effect of REEs on cultivation parameters and composition of the final product was assessed, together with their potential use for authentication purposes. The concentrations of REEs varied greatly among seven cultivation substrates and correlated with measurements in Cyclocybe cylindracea mushrooms; no such correlation was established in Pleurotus ostreatus. Reduction of hemicellulose, cellulose, and lignin in substrates during P. ostreatus cultivation was positively correlated with REE concentrations, which also affected the production performance depending on the species examined. In all cases, a negative correlation was established between bioconcentration factors (BCF) in mushrooms and REE content in substrates, while the effect of substrate composition on BCF values varied according to the element studied. The estimated daily intake values of REEs through mushroom consumption was at much lower levels than those reported as potentially harmful for human health. The content of REEs in cultivation substrates and in mushrooms revealed that the bioaccumulation of elements differed in each fungus. The nature/origin of substrates seemed to affect the concentration of REEs in mushrooms to a considerable extent. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

  8. Effect of silicon on activity coefficients of siderophile elements (Au, Pd, Pt, P, Ga, Cu, Zn, and Pb) in liquid Fe: Roles of core formation, late sulfide matte, and late veneer in shaping terrestrial mantle geochemistry

    NASA Astrophysics Data System (ADS)

    Righter, K.; Pando, K.; Humayun, M.; Waeselmann, N.; Yang, S.; Boujibar, A.; Danielson, L. R.

    2018-07-01

    Earth's core contains ∼10% of a light element that may be a combination of Si, S, C, O or H, with Si potentially being the major light element. Metal-silicate partitioning of siderophile elements can place important constraints on the P-T-fO2 and composition of the early Earth, but the effect of Si alloyed in Fe liquids is unknown for many of these elements. In particular, the effect of Si on the partitioning of highly siderophile elements (Au, Re and PGE) is virtually unknown. To address this gap in understanding, we have undertaken a systematic study of the highly siderophile elements Au, Pd, and Pt, and the volatile siderophile elements P, Ga, Cu, Zn, and Pb at variable Si content of metal, and 1600 °C and 1 GPa. From our experiments we derive epsilon interaction parameters between these elements and Si in Fe metallic liquids. The new parameters are used to update an activity model for trace siderophile elements in Fe alloys; Si causes large variation in the magnitude of activity coefficients of these elements in FeSi liquids. Because the interaction parameters are all positive, Si causes a decrease in their metal/silicate partition coefficients. We combine these new activity results with experimental studies of Au, Pd, Pt, P, Ga, Cu, Zn and Pb, to derive predictive expressions for metal/silicate partition coefficients which can then be applied to Earth. The expressions are applied to two scenarios for continuous accretion of Earth; specifically for constant and increasing fO2 during accretion. The results indicate that mantle concentrations of P, Ga, Cu, Zn, and Pb can be explained by metal-silicate equilibrium during accretion of the Earth where Earth's early magma ocean deepens to pressures of 40-60 GPa. Au, Pd, and Pt, on the other hand become too high in the mantle in such a scenario, and require a later removal mechanism, rather than an addition as traditionally argued. A late reduction event that removes 0.5% metal from a shallow magma ocean can lower the Au, Pd, and Pt contents to values near the current day BSE. On the other hand, removal of 0.2-1.0% of a late sulfide-rich matte to the core would lower the Au, Pd, and Pt concentrations in the mantle, but not to chondritic relative concentrations observed in the BSE. If sulfide matte is called upon to remove HSEs, they must be later added via a late veneer to re-establish the high and chondritic relative PUM concentrations. These results suggest that although accretion and core formation (involving a Si, S, and C-bearing metallic liquid) were the primary processes establishing many of Earth's mantle volatile elements and HSE, a secondary removal process is required to establish HSEs at their current and near-chondritic relative BSE levels. Mn and P - two siderophile elements that are central to biochemical processes (photosynthesis and triphosphates, respectively) - have significant and opposite interactions with FeSi liquids, and their mantle concentrations would be notably different if Earth had a Si-free core.

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

    NASA Astrophysics Data System (ADS)

    Rodrigues, Luiz Eduardo Oliveira Carmo; Mansur, Marcelo Borges

    The separation of rare earth elements, cobalt and nickel from NiMH battery residues is evaluated in this paper. Analysis of the internal content of the NiMH batteries shows that nickel is the main metal present in the residue (around 50% in weight), as well as potassium (2.2-10.9%), cobalt (5.1-5.5%), rare earth elements (15.3-29.0%) and cadmium (2.8%). The presence of cadmium reveals that some Ni-Cd batteries are possibly labeled as NiMH ones. The leaching of nickel and cobalt from the NiMH battery powder with sulfuric acid is efficient; operating variables temperature and concentration of H 2O 2 has no significant effect for the conditions studied. A mixture of rare earth elements is separated by precipitation with NaOH. Finally, solvent extraction with D2EHPA (di-2-ethylhexyl phosphoric acid) followed by Cyanex 272 (bis-2,4,4-trimethylpentyl phosphinic acid) can separate cadmium, cobalt and nickel from the leach liquor. The effect of the main operating variables of both leaching and solvent extraction steps are discussed aiming to maximize metal separation for recycling purposes.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Thorium: Issues and prospects in Malaysia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman

    2015-04-29

    In Malaysia, thorium exists in minerals and rare earth elements production residue. The average range of thorium content in Malaysian monazite and xenotime minerals was found about 70,000 and 15,000 ppm respectively. About 2,636 tonnes of Malaysian monazite was produced for a period of 5 years (2006-2010) and based on the above data, it can be estimated that Malaysian monazite contains about 184.5 tonnes of thorium. Although thorium can become a major radiological problem to our environment, but with the significant deposit of thorium in Malaysian monazite, it has a prospect as a future alternative fuel in nuclear technology. This papermore » will discuss the thorium issues in Malaysia especially its long term radiological risks to public health and environment at storage and disposal stages, the prospect of exploring and producing high purity thorium from our rare earth elements minerals for future thorium based reactor. This paper also highlights the holistic approach in thorium recovery from Malaysian rare earth element production residue to reduce its radioactivity and extraction of thorium and rare earth elements from the minerals with minimum radiological impact to health and environment.« less

  12. Partitioning of light lithophile elements during basalt eruptions on Earth and application to Martian shergottites

    NASA Astrophysics Data System (ADS)

    Edmonds, Marie

    2015-02-01

    An enigmatic record of light lithophile element (LLE) zoning in pyroxenes in basaltic shergottite meteorites, whereby LLE concentrations decrease dramatically from the cores to the rims, has been interpreted as being due to partitioning of LLE into a hydrous vapor during magma ascent to the surface on Mars. These trends are used as evidence that Martian basaltic melts are water-rich (McSween et al., 2001). Lithium and boron are light lithophile elements (LLE) that partition into volcanic minerals and into vapor from silicate melts, making them potential tracers of degassing processes during magma ascent to the surface of Earth and of other planets. While LLE degassing behavior is relatively well understood for silica-rich melts, where water and LLE concentrations are relatively high, very little data exists for LLE abundance, heterogeneity and degassing in basaltic melts. The lack of data hampers interpretation of the trends in the shergottite meteorites. Through a geochemical study of LLE, volatile and trace elements in olivine-hosted melt inclusions from Kilauea Volcano, Hawaii, it can be demonstrated that lithium behaves similarly to the light to middle rare Earth elements during melting, magma mixing and fractionation. Considerable heterogeneity in lithium and boron is inherited from mantle-derived primary melts, which is dominant over the fractionation and degassing signal. Lithium and boron are only very weakly volatile in basaltic melt erupted from Kilauea Volcano, with vapor-melt partition coefficients <0.1. Degassing of LLE is further inhibited at high temperatures. Pyroxene and associated melt inclusion LLE concentrations from a range of volcanoes are used to quantify lithium pyroxene-melt partition coefficients, which correlate negatively with melt H2O content, ranging from 0.13 at low water contents to <0.08 at H2O contents >4 wt%. The observed terrestrial LLE partitioning behavior is extrapolated to Martian primitive melts through modeling. The zoning observed in the shergottite pyroxenes is only consistent with degassing of LLE from a Martian melt near its liquidus temperature if the vapor-melt partition coefficient was an order of magnitude larger than observed on Earth. The range in LLE and trace elements observed in shergottite pyroxenes are instead consistent with concurrent mixing and fractionation of heterogeneous melts from the mantle.

  13. Influence of phase composition on microstructure and properties of Mg-5Al-0.4Mn-xRE (x = 0, 3 and 5 wt.%) alloys

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Braszczyńska-Malik, K.N., E-mail: kacha@wip.pcz.pl; Grzybowska, A.

    2016-05-15

    The microstructure and mechanical properties investigations of two AME503 and AME505 experimental alloys in as-cast conditions were presented. The investigated materials were fabricated on the basis of the AM50 commercial magnesium alloy with 3 and 5 wt.% cerium rich mischmetal. In the as-cast condition, both experimental alloys were mainly composed of α-Mg, Al{sub 11}RE{sub 3} and Al{sub 10}RE{sub 2}Mn{sub 7} intermetallic phases. Additionally, due to non-equilibrium solidification conditions, a small amount of α + γ divorced eutectic and Al{sub 2}RE intermetallic phase were revealed. The obtained results also show a significant influence of rare earth elements on Brinell hardness, tensilemore » and compression properties at ambient temperature and especially on creep properties at 473 K. Improved alloy properties with a rise in rare earth elements mass fraction results from an increase in Al{sub 11}RE{sub 3} phase volume fraction and suppression of α + γ eutectic volume fraction in the alloy microstructure. Additionally, the influence of rare earth elements on the dendrite arm space value was discussed. The presented results also proved the thermal stability of the intermetallic phases during creep testing. - Highlights: • Two different Mg-5Al-0.4Mn alloys containing 3 and 5 wt.% of rare earth elements were fabricated. • Addition of rare earth elements leads to a reduction of dendrite arm spaces. • Mechanical properties depend on the phase composition of the alloys. • The increase of the rare earth elements content causes rise of the creep resistance.« less

  14. Mineralogical and geochemical evidence for hydrothermal activity at the west wall of 12°50′N core complex (Mid-Atlantic ridge): a new ultramafic-hosted seafloor hydrothermal deposit?

    USGS Publications Warehouse

    Dekov, Vesselin; Boycheva, Tanya; Halenius, Ulf; Billstrom, Kjell; Kamenov, George D.; Shanks, Wayne C.; Stummeyer, Jens

    2011-01-01

    Dredging along the west wall of the core complex at 12°50′N Mid-Atlantic Ridge sampled a number of black oxyhydroxide crusts and breccias cemented by black and dark brown oxyhydroxide matrix. Black crusts found on top of basalt clasts (rubble) are mainly composed of Mn-oxides (birnessite, 10-Å manganates) with thin films of nontronite and X-ray amorphous FeOOH on their surfaces. Their chemical composition (low trace- and rare earth-element contents, high Li and Ag concentrations, rare earth element distribution patterns with negative both Ce and Eu anomalies), Sr–Nd–Pb-isotope systematic and O-isotope data suggest low-temperature (~ 20 °C) hydrothermal deposition from a diffuse vent area on the seafloor. Mineralogical, petrographic and geochemical investigations of the breccias showed the rock clasts were hydrothermally altered fragments of MORBs. Despite the substantial mineralogical changes caused by the alteration the Sr–Nd–Pb-isotope ratios have not been significantly affected by this process. The basalt clasts are cemented by dark brown and black matrix. Dark brown cement exhibits geochemical features (very low trace- and rare earth- element contents, high U concentration, rare earth element distribution pattern with high positive Eu anomaly) and Nd–Pb-isotope systematics (similar to that of MORB) suggesting that the precursor was a primary, high-temperature Fe-sulfide, which was eventually altered to goethite at ambient seawater conditions. The data presented in this work points towards the possible existence of high- and low-temperature hydrothermal activity at the west wall of the core complex at 12°50′N Mid-Atlantic Ridge. Tectonic setting at the site implies that the proposed hydrothermal field is possibly ultramafic-hosted.

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

    USGS Publications Warehouse

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

    1992-01-01

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

  16. Systematic variation of rare earths in monazite

    USGS Publications Warehouse

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

    1953-01-01

    Ten monazites from widely scattered localities have been analyzed for La, Ce, Pr, Nd, Sm, Gd, Y and Th by means of a combined chemical and emission spectrographic method. The analytical results, calculated to atomic percent of total rare earths (thorium excluded), show a considerable variation in the proportions of every element except praseodymium, which is relatively constant. The general variation trends of the elements may be calculated by assuming that the monazites represent different stages in a fractional precipitation process, and by assuming that there is a gradational increase in the precipitability of rare earth elements with decreasing ionic radius. Fractional precipitation brings about an increase in lanthanum and cerium, little change in praseodymium, and a decrease in neodymium, samarium, gadolinium, and yttrium. Deviations from the calculated lines of variation consist of a simultaneous, abnormal increase or decrease in the proportions of cerium, praseodymium, and neodymium with antipathetic decrease or increase in the proportions of the other elements. These deviations are ascribed to abnormally high or low temperatures that affect the precipitability of the central trio of elements (Ce, Pr, Nd) relatively more than that of the other elements. The following semiquantitative rules have been found useful in describing the composition of rare earths from monazite: 1. 1. The sum of lanthanum and neodymium is very nearly a constant at 42 ?? 2 atomic percent. 2. 2. Praseodymium is very nearly constant at 5 ?? 1 atomic percent. 3. 3. The sum of Ce, Sm, Gd, and Y is very nearly a constant at 53 ?? 3 atomic percent. No correlation could be established between the content of Th and that of any of the rare earth elements. ?? 1953.

  17. The tremendous potential of deep-sea mud as a source of rare-earth elements.

    PubMed

    Takaya, Yutaro; Yasukawa, Kazutaka; Kawasaki, Takehiro; Fujinaga, Koichiro; Ohta, Junichiro; Usui, Yoichi; Nakamura, Kentaro; Kimura, Jun-Ichi; Chang, Qing; Hamada, Morihisa; Dodbiba, Gjergj; Nozaki, Tatsuo; Iijima, Koichi; Morisawa, Tomohiro; Kuwahara, Takuma; Ishida, Yasuyuki; Ichimura, Takao; Kitazume, Masaki; Fujita, Toyohisa; Kato, Yasuhiro

    2018-04-10

    Potential risks of supply shortages for critical metals including rare-earth elements and yttrium (REY) have spurred great interest in commercial mining of deep-sea mineral resources. Deep-sea mud containing over 5,000 ppm total REY content was discovered in the western North Pacific Ocean near Minamitorishima Island, Japan, in 2013. This REY-rich mud has great potential as a rare-earth metal resource because of the enormous amount available and its advantageous mineralogical features. Here, we estimated the resource amount in REY-rich mud with Geographical Information System software and established a mineral processing procedure to greatly enhance its economic value. The resource amount was estimated to be 1.2 Mt of rare-earth oxide for the most promising area (105 km 2  × 0-10 mbsf), which accounts for 62, 47, 32, and 56 years of annual global demand for Y, Eu, Tb, and Dy, respectively. Moreover, using a hydrocyclone separator enabled us to recover selectively biogenic calcium phosphate grains, which have high REY content (up to 22,000 ppm) and constitute the coarser domain in the grain-size distribution. The enormous resource amount and the effectiveness of the mineral processing are strong indicators that this new REY resource could be exploited in the near future.

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

    NASA Astrophysics Data System (ADS)

    Yang, Shou Ye; Jung, Hoi Soo; Choi, Man Sik; Li, Cong Xian

    2002-07-01

    Thirty-four samples from the Changjiang and Huanghe were analyzed to characterize their rare earth element (REE) compositions. Although REE concentrations in the Changjiang sediments are higher than those of the Huanghe sediments, the former are less variable. Bulk samples and acid-leachable fractions have convex REE patterns and middle REE enrichments relative to upper continental crust, whereas flat patterns are present in the residual fractions. Source rock composition is the primary control on REE composition, and weathering processes play a minor role. Grain size exerts some influence on REE composition, as demonstrated by the higher REE contents of clay minerals in sediments from both rivers. Heavy minerals contribute about 10-20% of the total REE in the sediments. Apatite is rare in the river sediments, and contributes less than 2% of the REE content, but other heavy minerals such as sphene, allanite and zircon are important reservoirs of residual REE fractions. The Fe-Mn oxides phase accounts for about 14% of bulk REE content in the Changjiang sediments, which could be one of the more important factors controlling REE fractionation in the leachable fraction.

  19. ThMn12-type phases for magnets with low rare-earth content: Crystal-field analysis of the full magnetization process.

    PubMed

    Tereshina, I S; Kostyuchenko, N V; Tereshina-Chitrova, E A; Skourski, Y; Doerr, M; Pelevin, I A; Zvezdin, A K; Paukov, M; Havela, L; Drulis, H

    2018-02-26

    Rare-earth (R)-iron alloys are a backbone of permanent magnets. Recent increase in price of rare earths has pushed the industry to seek ways to reduce the R-content in the hard magnetic materials. For this reason strong magnets with the ThMn 12  type of structure came into focus. Functional properties of R(Fe,T) 12 (T-element stabilizes the structure) compounds or their interstitially modified derivatives, R(Fe,T) 12 -X (X is an atom of hydrogen or nitrogen) are determined by the crystal-electric-field (CEF) and exchange interaction (EI) parameters. We have calculated the parameters using high-field magnetization data. We choose the ferrimagnetic Tm-containing compounds, which are most sensitive to magnetic field and demonstrate that TmFe 11 Ti-H reaches the ferromagnetic state in the magnetic field of 52 T. Knowledge of exact CEF and EI parameters and their variation in the compounds modified by the interstitial atoms is a cornerstone of the quest for hard magnetic materials with low rare-earth content.

  20. Partitioning of Large-ion Lithophile Elements Between Aqueous Fluids and Melts: Role of Saline Fluids in Sub-arc Mantle

    NASA Astrophysics Data System (ADS)

    Kawamoto, T.; Mibe, K.

    2014-12-01

    Chemical fractionation of slab-derived supercritical fluids can play an important role in elemental transfer from subducting slab to the mantle wedge and arc magmatism [1]. Recent findings of saline fluids from sub-arc mantle peridotite indicate that aqueous fluids in mantle wedge can contain 3.7 wt% NaCl in Ichinomageta, Northeast Japan arc [2] to 5.1 wt% NaCl in Pinatubo, Luzon arc [3]. It is, therefore, important to determine the effect of Cl on the trace element partitioning between aqueous fluids and melts. Synchrotron radiation X-ray fluorescence (XRF) analysis is conducted to know Rb, Sr, and Pb partitioning between aqueous fluids and melts [4]. There is a positive correlation between partition coefficients and pressure, as well as salinity. Two slab-derived components, melt and fluid components, are suggested to explain trace element characteristics of arc-basalts in the Mariana arc [5]. The fluid component is characterized by enrichment of alkali and alkali earth elements. Such features can be explained if the fluid component is a saline fluid, because alkali earth elements and Pb are much less mobile with Cl-free fluids than Cl-rich fluids [4]. We suggest that slab-derived components have compositional features consistent with a saline fluid and a melt, which can be formed through a separation of a slab-derived supercritical fluid [1]. Slab derived supercritical fluids contain Cl, and aqueous fluids inherit much of the Cl and some of the large-ion lithophile elements. [1] Kawamoto et al. 2012, Separation of supercritical slab-fluids to form aqueous fluid and melt components in subduction zone magmatism. PNAS, pnas.org/content/109/46/18695 [2] Kumagai et al. Evolution of carbon dioxide bearing saline fluids in the mantle wedge beneath the Northeast Japan arc, CMP [3] Kawamoto et al. 2013, Mantle wedge infiltrated with saline fluids from dehydration and decarbonation of subducting slab. PNAS, pnas.org/content/110/24/9663 [4] Kawamoto et al. 2014, Large ion lithophile elements delivered by saline fluids to the sub-arc mantle, EPS, earth-planets-space.com/content/66/1/61 [5] Pearce et al. 2005, Geochemical mapping of the Mariana arc-basin system: Implications for the nature and distribution of subduction components. G-cubed, onlinelibrary.wiley.com/doi/10.1029/2004GC000895/full

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

    NASA Astrophysics Data System (ADS)

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

    1981-04-01

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

  2. Effect of light elements on the sound velocities in solid iron: Implications for the composition of Earth's core

    NASA Astrophysics Data System (ADS)

    Badro, James; Fiquet, Guillaume; Guyot, François; Gregoryanz, Eugene; Occelli, Florent; Antonangeli, Daniele; d'Astuto, Matteo

    2007-02-01

    We measured compressional sound velocities in light element alloys of iron (FeO, FeSi, FeS, and FeS2) at high-pressure by inelastic X-ray scattering. This dataset provides new mineralogical constraints on the composition of Earth's core, and completes the previous sets formed by the pressure-density systematics for these compounds. Based on the combination of these datasets and their comparison with radial seismic models, we propose an average composition model of the Earth's core. We show that the incorporation of small amounts of silicon or oxygen is compatible with geophysical observations and geochemical abundances. The effect of nickel on the calculated light element contents is shown to be negligible. The preferred core model derived from our measurements is an inner core which contains 2.3 wt.% silicon and traces of oxygen, and an outer core containing 2.8 wt.% silicon and around 5.3 wt.% oxygen.

  3. Trends in the Rare Earth Element Content of U.S.-Based Coal Combustion Fly Ashes.

    PubMed

    Taggart, Ross K; Hower, James C; Dwyer, Gary S; Hsu-Kim, Heileen

    2016-06-07

    Rare earth elements (REEs) are critical and strategic materials in the defense, energy, electronics, and automotive industries. The reclamation of REEs from coal combustion fly ash has been proposed as a way to supplement REE mining. However, the typical REE contents in coal fly ash, particularly in the United States, have not been comprehensively documented or compared among the major types of coal feedstocks that determine fly ash composition. The objective of this study was to characterize a broad selection of U.S. fly ashes of varied geological origin in order to rank their potential for REE recovery. The total and nitric acid-extractable REE content for more than 100 ash samples were correlated with characteristics such as the major element content and coal basin to elucidate trends in REE enrichment. Average total REE content (defined as the sum of the lanthanides, yttrium, and scandium) for ashes derived from Appalachian sources was 591 mg kg(-1) and significantly greater than in ashes from Illinois and Powder River basin coals (403 and 337 mg kg(-1), respectively). The fraction of critical REEs (Nd, Eu, Tb, Dy, Y, and Er) in the fly ashes was 34-38% of the total and considerably higher than in conventional ores (typically less than 15%). Powder River Basin ashes had the highest extractable REE content, with 70% of the total REE recovered by heated nitric acid digestion. This is likely due to the higher calcium content of Powder River Basin ashes, which enhances their solubility in nitric acid. Sc, Nd, and Dy were the major contributors to the total REE value in fly ash, based on their contents and recent market prices. Overall, this study shows that coal fly ash production could provide a substantial domestic supply of REEs, but the feasibility of recovery depends on the development of extraction technologies that could be tailored to the major mineral content and origins of the feed coal for the ash.

  4. Mineralogical and Geochemical Discrimination of the Occurrence and Genesis of Palygorskite in Eocene Sediments on the Northeastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Ye, Chengcheng; Yang, Yibo; Fang, Xiaomin; Hong, Hanlie; Zhang, Weilin; Yang, Rongsheng; Song, Bowen; Zhang, Zhiguo

    2018-03-01

    Palygorskite is a widely used indicator of semiarid to arid environments in paleoclimate studies. In this study, we present detailed mineralogical and geochemical investigations exploring the genesis of palygorskite found in Eocene fluvial sediment in the northern Qaidam Basin on the northeastern Tibetan Plateau. The presence of two types of palygorskite is revealed, based on their crystallinity characteristics and distinctive rare earth element (REE) patterns in the coexisting clay fraction. Well-crystallized palygorskite samples are characterized by remarkably negative Ce anomalies and obvious middle rare earth element enrichment. Poorly crystallized palygorskite samples generally exhibit positive Ce anomalies and less pronounced middle rare earth element enrichment, which resemble those of nonpalygorskite-bearing clay samples. Given the presence of an overall oxidized fluvial sedimentary environment, we attribute the well-crystallized palygorskite (which has textures comprising long, interwoven fibers) to direct precipitation (i.e., neoformation) occurring within a reducing environment during early/postdepositional processes while the poorly crystallized palygorskite (which is characterized by short, club-shaped single crystals) originates as catchment-delivered detritus. These poorly crystallized palygorskites occur mostly in 49.5-47.0 Ma and are accompanied by decreasing kaolinite content, increasing chlorite content, and abundant xerophytic spore-pollen from the Qaidam Basin, and its neighboring Xining Basin. Collectively, these evidences suggest that a less humid climate followed after the Early Eocene Climate Optimum.

  5. Geochemistry of rare earth elements in Permian coals from the Huaibei Coalfield, China

    USGS Publications Warehouse

    Zheng, Lingyun; Liu, Gaisheng; Chou, C.-L.; Qi, C.; Zhang, Y.

    2007-01-01

    The rare earth elements (REEs) in coals are important because of: (a) REE patterns can be an indicator of the nature of source rocks of the mineral matter as well as sedimentary environments; (b) REEs abundance in coal may have industrial-significance. In this study, a total of thirty-four samples of Permian coal, partings, roof, and floor were collected from the Huaibei Coalfield, Anhui Province, China. Abundances of rare earth elements (REEs) and other elements in the samples were determined by inductively coupled-plasma mass spectrometry (ICP-MS) and inductively coupled-plasma atomic emission spectrometry (ICP-AES). The results show that the REEs are enriched in coals in the Huaibei Coalfield as compared with Chinese and U.S. coals and the world coal average. Coals in the Lower Shihezi Formation (No. 7, 5, and 4 Coals) and Upper Shihezi Formation (No. 3) have higher REE abundances than the coals in Shanxi Formation (No. 10). Magmatic intrusion resulted in high enrichment of REEs concentrations in No. 5 and 7 Coals. The REE abundances are positively correlated with the ash content. The mineral matter in these coals is mainly made up of clay minerals and carbonates. The REEs are positively correlated with lithophile elements including Si, Al, Ti, Fe, and Na, which are mainly distributed in clay minerals, indicating that REEs are contained mainly in clay minerals. The REE abundances in coals normalized by the ash are higher than that in partings. REEs abundances of coals cannot be accounted for by the REE content in the mineral matter, and some REEs associated with organic matter in coals. ?? 2007 Elsevier Ltd. All rights reserved.

  6. Sedimentology and geochemistry of mud volcanoes in the Anaximander Mountain Region from the Eastern Mediterranean Sea.

    PubMed

    Talas, Ezgi; Duman, Muhammet; Küçüksezgin, Filiz; Brennan, Michael L; Raineault, Nicole A

    2015-06-15

    Investigations carried out on surface sediments collected from the Anaximander mud volcanoes in the Eastern Mediterranean Sea to determine sedimentary and geochemical properties. The sediment grain size distribution and geochemical contents were determined by grain size analysis, organic carbon, carbonate contents and element analysis. The results of element contents were compared to background levels of Earth's crust. The factors that affect element distribution in sediments were calculated by the nine push core samples taken from the surface of mud volcanoes by the E/V Nautilus. The grain size of the samples varies from sand to sandy silt. Enrichment and Contamination factor analysis showed that these analyses can also be used to evaluate of deep sea environmental and source parameters. It is concluded that the biological and cold seep effects are the main drivers of surface sediment characteristics from the Anaximander mud volcanoes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Evaporative fractionation of volatile stable isotopes and their bearing on the origin of the Moon

    PubMed Central

    Day, James M. D.; Moynier, Frederic

    2014-01-01

    The Moon is depleted in volatile elements relative to the Earth and Mars. Low abundances of volatile elements, fractionated stable isotope ratios of S, Cl, K and Zn, high μ (238U/204Pb) and long-term Rb/Sr depletion are distinguishing features of the Moon, relative to the Earth. These geochemical characteristics indicate both inheritance of volatile-depleted materials that formed the Moon and planets and subsequent evaporative loss of volatile elements that occurred during lunar formation and differentiation. Models of volatile loss through localized eruptive degassing are not consistent with the available S, Cl, Zn and K isotopes and abundance data for the Moon. The most probable cause of volatile depletion is global-scale evaporation resulting from a giant impact or a magma ocean phase where inefficient volatile loss during magmatic convection led to the present distribution of volatile elements within mantle and crustal reservoirs. Problems exist for models of planetary volatile depletion following giant impact. Most critically, in this model, the volatile loss requires preferential delivery and retention of late-accreted volatiles to the Earth compared with the Moon. Different proportions of late-accreted mass are computed to explain present-day distributions of volatile and moderately volatile elements (e.g. Pb, Zn; 5 to >10%) relative to highly siderophile elements (approx. 0.5%) for the Earth. Models of early magma ocean phases may be more effective in explaining the volatile loss. Basaltic materials (e.g. eucrites and angrites) from highly differentiated airless asteroids are volatile-depleted, like the Moon, whereas the Earth and Mars have proportionally greater volatile contents. Parent-body size and the existence of early atmospheres are therefore likely to represent fundamental controls on planetary volatile retention or loss. PMID:25114311

  8. Elemental bioimaging by means of LA-ICP-OES: investigation of the calcium, sodium and potassium distribution in tobacco plant stems and leaf petioles.

    PubMed

    Thyssen, G M; Holtkamp, M; Kaulfürst-Soboll, H; Wehe, C A; Sperling, M; von Schaewen, A; Karst, U

    2017-06-21

    Laser ablation-inductively coupled plasma-optical emission spectroscopy (LA-ICP-OES) is presented as a valuable tool for elemental bioimaging of alkali and earth alkali elements in plants. Whereas LA-ICP-OES is commonly used for micro analysis of solid samples, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) has advanced to the gold standard for bioimaging. However, especially for easily excitable and ubiquitous elements such as alkali and earth alkali elements, LA-ICP-OES holds some advantages regarding simultaneous detection, costs, contamination, and user-friendliness. This is demonstrated by determining the calcium, sodium and potassium distribution in tobacco plant stem and leaf petiole tissues. A quantification of the calcium contents in a concentration range up to 1000 μg g -1 using matrix-matched standards is presented as well. The method is directly compared to a LA-ICP-MS approach by analyzing parallel slices of the same samples.

  9. Modelling of Equilibrium Between Mantle and Core: Refractory, Volatile, and Highly Siderophile Elements

    NASA Technical Reports Server (NTRS)

    Righter, K.; Danielson, L.; Pando, K.; Shofner, G.; Lee, C. -T.

    2013-01-01

    Siderophile elements have been used to constrain conditions of core formation and differentiation for the Earth, Mars and other differentiated bodies [1]. Recent models for the Earth have concluded that the mantle and core did not fully equilibrate and the siderophile element contents of the mantle can only be explained under conditions where the oxygen fugacity changes from low to high during accretion and the mantle and core do not fully equilibrate [2,3]. However these conclusions go against several physical and chemical constraints. First, calculations suggest that even with the composition of accreting material changing from reduced to oxidized over time, the fO2 defined by metal-silicate equilibrium does not change substantially, only by approximately 1 logfO2 unit [4]. An increase of more than 2 logfO2 units in mantle oxidation are required in models of [2,3]. Secondly, calculations also show that metallic impacting material will become deformed and sheared during accretion to a large body, such that it becomes emulsified to a fine scale that allows equilibrium at nearly all conditions except for possibly the length scale for giant impacts [5] (contrary to conclusions of [6]). Using new data for D(Mo) metal/silicate at high pressures, together with updated partitioning expressions for many other elements, we will show that metal-silicate equilibrium across a long span of Earth s accretion history may explain the concentrations of many siderophile elements in Earth's mantle. The modeling includes refractory elements Ni, Co, Mo, and W, as well as highly siderophile elements Au, Pd and Pt, and volatile elements Cd, In, Bi, Sb, Ge and As.

  10. Solvent Extraction of Rare Earth Elements from a Nitric Acid Leach Solution of Apatite by Mixtures of Tributyl Phosphate and Di-(2-ethylhexyl) Phosphoric Acid

    NASA Astrophysics Data System (ADS)

    Ferdowsi, Ali; Yoozbashizadeh, Hossein

    2017-12-01

    Solvent extraction of rare earths from nitrate leach liquor of apatite using mixtures of tributyl phosphate (TBP) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) was studied. The effects of nitrate and hydrogen ion concentration of the aqueous phase as well as the composition and concentration of extractants in the organic phase on the extraction behavior of lanthanum, cerium, neodymium, and yttrium were investigated. The distribution ratio of REEs increases by increasing the nitrate concentration in aqueous phase and concentration of extractants in organic phase, but the hydrogen ion concentration in aqueous phase has a decreasing effect. Yttrium as a heavy rare earth is more sensitive to these parameters than light rare earth elements. Although the composition of organic phase has a minor effect on the extraction of light rare earths, the percent of extraction of yttrium decreases dramatically by increasing the TBP content of organic phase. Mixtures of TBP and D2EHPA can show either synergism or antagonism extraction depending on the concentration and composition of extractants in organic phase. The best condition for separating rare earth elements in groups of heavy and light REEs can be achieved at high nitrate concentration, low H+ concentration, and high concentration of D2EHPA in organic phase. Separation of Ce and La by TBP and D2EHPA is practically impossible in the studied conditions; however, low nitrate concentration and high hydrogen ion concentration in aqueous phase and low concentration of extractants in organic phase favor the separation of Nd from other light rare earth elements.

  11. U, Th, and K in planetary cores: Implications for volatile elements and heat production

    NASA Astrophysics Data System (ADS)

    Boujibar, A.; Habermann, M.; Righter, K.; Ross, D. K.; Righter, M.; Chidester, B.; Rapp, J. F.; Danielson, L. R.; Pando, K.; Andreasen, R.

    2016-12-01

    The accretion of terrestrial planets is known to be accompanied with volatile loss due to strong solar winds produced by the young Sun and due to energetic impacts. It was previously expected that Mercury, the innermost planet is depleted in volatile elements in comparison to other terrestrial planets. These predictions have been recently challenged by the MESSENGER mission to Mercury that detected relatively high K/U and K/Th ratios on Mercury's surface, suggesting a volatile content similar to Earth and Mars. However previous studies showed that Fe-rich metals can incorporate substantial U, Th and K under reducing conditions and with high sulfur contents, which are two conditions relevant to Mercury. In order to quantify the fractionation of these heat-producing elements during core segregation, we determined experimentally their partition coefficients (Dmet/sil) between metal and silicate at varying pressure, temperature, oxygen fugacity and sulfur content. Our data confirm that U, Th, and K become more siderophile with decreasing fO2 and increasing sulfur content, with a stronger effect for U and Th in comparison to K. Hence Mercury's core is likely to have incorporated more U and Th than K, resulting in the elevated K/U and K/Th ratios measured on the surface. The bulk concentrations of U, Th, and K in terrestrial planets (Mercury, Venus, Earth and Mars) are calculated based on geochemical constraints on core-mantle differentiation. Significant amounts of U, Th and K are partitioned into the cores of Mercury, Venus and Earth, but much less into Mars' core. The resulting bulk planet K/U and K/Th correlate with the heliocentric distance, which suggests an overall volatile depletion in the inner Solar System. These results have important implications for internal heat production. The role of impact erosion on the evolution of Th/U ratio will also be addressed.

  12. Archaean ultra-depleted komatiites formed by hydrous melting of cratonic mantle.

    PubMed

    Wilson, A H; Shirey, S B; Carlson, R W

    2003-06-19

    Komatiites are ultramafic volcanic rocks containing more than 18 per cent MgO (ref. 1) that erupted mainly in the Archaean era (more than 2.5 gigayears ago). Although such compositions occur in later periods of Earth history (for example, the Cretaceous komatiites of Gorgona Island), the more recent examples tend to have lower MgO content than their Archaean equivalents. Komatiites are also characterized by their low incompatible-element content, which is most consistent with their generation by high degrees of partial melting (30-50 per cent). Current models for komatiite genesis include the melting of rock at great depth in plumes of hot, diapirically rising mantle or the melting of relatively shallow mantle rocks at less extreme, but still high, temperatures caused by fluxing with water. Here we report a suite of ultramafic lava flows from the Commondale greenstone belt, in the southern part of the Kaapvaal Craton, which represents a previously unrecognized type of komatiite with exceptionally high forsterite content of its igneous olivines, low TiO(2)/Al(2)O(3) ratio, high silica content, extreme depletion in rare-earth elements and low Re/Os ratio. We suggest a model for their formation in which a garnet-enriched residue left by earlier cratonic volcanism was melted by hydration from a subducting slab.

  13. Equation of State of Fe3C and Implications for the Carbon Content of Earth's Core

    NASA Astrophysics Data System (ADS)

    Davis, A.; Brauser, N.; Thompson, E. C.; Chidester, B.; Greenberg, E.; Prakapenka, V. B.; Campbell, A.

    2017-12-01

    Carbon is a common component in protoplanetary cores, as represented by iron meteorites. Therefore, along with silicon, oxygen, and other light elements, it is likely to be an alloying component with iron in Earth's core. Previous studies of the densities of iron carbides have not reached the combined pressure and temperature conditions relevant to Earth's core. To better understand the geophysical implications of carbon addition to Earth's core, we report P-V-T measurements of Fe3C to pressures and temperatures exceeding 110 GPa and 2500 K, using synchrotron X-ray diffraction in a laser heated diamond anvil cell. Fitting these measurements to an equation of state and assuming 1.5% density change upon melting and a 4000 K core-mantle boundary temperature, we report a value of 6 wt% carbon necessary to match the PREM density in the outer core. This value should be considered an upper bound due to the likely presence of other light elements.

  14. Uranium, thorium and REE partitioning into sulfide liquids at high pressure and high temperature: Implications for reduced, S-rich planetary bodies

    NASA Astrophysics Data System (ADS)

    Wohlers, A.; Wood, B. J.

    2017-12-01

    Based on models of the young solar nebula it is likely that the inner planets went through an early reduced phase of accretion with high metal/silicate ratio and low volatile element contents. Mercury is an existing example of a large planetary embryo with these characteristics but also with a very high S content. In order to investigate the geochemical evolution of Mercury-like bodies we experimentally determined the partitioning of lithophile elements (U, Th, Eu, Sm, Nd, Zr, La, Ce, Yb) between sulfide liquid, low-S metals and silicate melt at 1.5 GPa and 1400-2100˚C. Our results, when combined with those of Wohlers and Wood (2015) show that under highly reducing conditions (FeOsilicate<1wt%) U, Sm, Nd and other lithophile elements partition strongly into FeS liquids relative to silicate melts. The dependences of D's on the FeS contents of the metal and FeO contents of the silicate may be understood in terms of exchange reactions: UO2 + 2FeS = 2FeO + US2silicate sulfide silicate sulfideHigh concentrations of FeSmetal and low FeO contents of the silicate melts drive the reaction to the right, yielding high US2 in the sulfide and high DU. A second effect which raises DU (and other lithophile D's) is the S content of the silicate melt. The latter increases rapidly at low FeO contents and reaches 11wt %. This greatly reduces the activity coefficient of FeO, displacing the reaction further to the right. At 1.5GPa and 1400˚C we obtain sulfide-silicate partitioning with DNd/DSm 1.4 and DTh 0.1DU. As temperature increases to 2100˚C, DNd/DSm declines to 1.0 and DTh/DU increases to 0.3. We estimated the effects of accreting a reduced sulfur-rich component (with FeS core) added to early Earth. The results at 1400˚C imply the possibility of a significant ( 11ppm) 142Nd anomaly in silicate Earth and the addition of >8 ppb U to the core, but require an unreasonably high Th/U of silicate Earth (4.54). Results at 2100˚C lead to a 142Nd anomaly of 0 but addition of such a reduced sulfur-rich body could add up to 10 ppb of U to the core, together with 21 ppb Th. This combination would generate 3 TW of the energy required for the geodynamo. In this case, the Th/U ratio of silicate Earth would be 4.3, within the range of some estimates. Wohlers A. & Wood B.J. (2015) A Mercury-like component of early Earth yield uranium in the core and high mantle Nd142. Nature 520, 337-340

  15. Tank bromeliads capture Saharan dust in El Yunque National Forest, Puerto Rico

    NASA Astrophysics Data System (ADS)

    Royer, Dana L.; Moynihan, Kylen M.; Ariori, Carolyn; Bodkin, Gavin; Doria, Gabriela; Enright, Katherine; Hatfield-Gardner, Rémy; Kravet, Emma; Nuttle, C. Miller; Shepard, Lisa; Ku, Timothy C. W.; O'Connell, Suzanne; Resor, Phillip G.

    2018-01-01

    Dust from Saharan Africa commonly blows across the Atlantic Ocean and into the Caribbean. Most methods for measuring this dust either are expensive if collected directly from the atmosphere, or depend on very small concentrations that may be chemically altered if collected from soil. Tank bromeliads in the dwarf forest of El Yunque National Forest, Puerto Rico, have a structure of overlapping leaves used to capture rainwater and other atmospheric inputs. Therefore, it is likely that these bromeliads are collecting in their tanks Saharan dust along with local inputs. Here we analyze the elemental chemistry, including rare earth elements (REEs), of tank contents in order to match their chemical fingerprint to a provenance of the Earth's crust. We find that the tank contents differ from the local soils and bedrock and are more similar to published values of Saharan dust. Our study confirms the feasibility of using bromeliad tanks to trace Saharan dust in the Caribbean.

  16. Rare Earth Element Yttrium Modified Mg-Al-Zn Alloy: Microstructure, Degradation Properties and Hardness

    PubMed Central

    Liu, Long; Yuan, Fulai; Zhao, Mingchun; Gao, Chengde; Feng, Pei; Yang, Youwen; Yang, Sheng; Shuai, Cijun

    2017-01-01

    The overly-fast degradation rates of magnesium-based alloys in the biological environment have limited their applications as biodegradable bone implants. In this study, rare earth element yttrium (Y) was introduced into AZ61 magnesium alloy (Mg-6Al-1Zn wt %) to control the degradation rate by laser rapid melting. The results showed that the degradation rate of AZ61 magnesium alloy was slowed down by adding Y. This was attributed to the reduction of Mg17Al12 phase and the formation of Al2Y phase that has a more active potential, which decreased galvanic corrosion resulting from its coupling with the anodic matrix phase. Meanwhile, the hardness increased as Y contents increased due to the uniform distribution of the Al2Y and Mg17Al12 phases. However, as the Y contents increased further, the formation of excessive Al2Y phase resulted in the increasing of degradation rate and the decreasing of hardness due to its agglomeration. PMID:28772837

  17. Combined effects of simulated acid rain and lanthanum chloride on chloroplast structure and functional elements in rice.

    PubMed

    Hu, Huiqing; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2016-05-01

    Acid rain and rare earth element (REE) pollution exist simultaneously in many agricultural regions. However, how REE pollution and acid rain affect plant growth in combination remains largely unknown. In this study, the combined effects of simulated acid rain and lanthanum chloride (LaCl3) on chloroplast morphology, chloroplast ultrastructure, functional element contents, chlorophyll content, and the net photosynthetic rate (P n) in rice (Oryza sativa) were investigated by simulating acid rain and rare earth pollution. Under the combined treatment of simulated acid rain at pH 4.5 and 0.08 mM LaCl3, the chloroplast membrane was smooth, proteins on this membrane were uniform, chloroplast structure was integrated, and the thylakoids were orderly arranged, and simulated acid rain and LaCl3 exhibited a mild antagonistic effect; the Mg, Ca, Mn contents, the chlorophyll content, and the P n increased under this combined treatment, with a synergistic effect of simulated acid rain and LaCl3. Under other combined treatments of simulated acid rain and LaCl3, the chloroplast membrane surface was uneven, a clear "hole" was observed on the surface of chloroplasts, and the thylakoids were dissolved and loose; and the P n and contents of functional elements (P, Mg, K, Ca, Mn, Fe, Ni, Cu, Zn and Mo) and chlorophyll decreased. Under these combined treatments, simulated acid rain and LaCl3 exhibited a synergistic effect. Based on the above results, a model of the combined effects of simulated acid rain and LaCl3 on plant photosynthesis was established in order to reveal the combined effects on plant photosynthesis, especially on the photosynthetic organelle-chloroplast. Our results would provide some references for further understanding the mechanism of the combined effects of simulated acid rain and LaCl3 on plant photosynthesis.

  18. Petrogenesis of ore-bearing porphyry in non-subduction setting: a case study of the Eocene potassic intrusions in the western Yangtze Block

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Liao, Shi-Yong; Zhou, Qing; Zhang, Xin

    2018-05-01

    In the western Yangtze Block, abundant Eocene ( 38-34 Ma) potassic adakite-like intrusions and associated porphyry copper deposits are exposed in non-subduction setting, including Machangjing, Beiya, Binchuan, Habo and Tongchang intrusions. All these ore-bearing porphyries share many geochemical characteristics of adakite such as depletion in heavy rare earth elements (HREEs), enrichment in Sr and Ba, absence of negative Eu anomalies, high SiO2, Al2O3, Sr/Y, La/Yb and low Y, Yb contents. They also exhibit affinities of potassic rocks, e.g., alkali-rich, high K2O/Na2O ratios and enrichment in light rare earth elements (LREEs) and large ion lithophile elements (LILEs). Their Sr-Nd isotopic ratios are similar to coeval shoshonitic lamprophyres. Geochemical data indicate that they were probably produced by partial melting of newly underplated potassic rocks sourced from a modified and enriched lithospheric mantle. These underplated rocks have elevated oxygen fugacity, water and copper contents, with high metallogenic potential. We propose that all the studied potassic rocks were emplaced in a post-collisional setting, associated with the local removal of lithospheric mantle.

  19. Geochemistry of trace elements in coals from the Zhuji Mine, Huainan Coalfield, Anhui, China

    USGS Publications Warehouse

    Sun, R.; Liu, Gaisheng; Zheng, Lingyun; Chou, C.-L.

    2010-01-01

    The abundances of nine major elements and thirty-eight trace elements in 520 samples of low sulfur coals from the Zhuji Mine, Huainan Coalfield, Anhui, China, were determined. Samples were mainly collected from 10 minable coal seams of 29 boreholes during exploration. The B content in coals shows that the influence of brackish water decreased toward the top of coal seams; marine transgression and regression occurred frequently in the Lower Shihezi Formation. A wide range of elemental abundances is found. Weighted means of Na, K, Fe, P, Be, B, Co, Ni, Cr, Se, Sb, Ba, and Bi abundances in Zhuji coals are higher, and the remainder elements are either lower or equal to the average values of elements in coals of northern China. Compared to the Chinese coals, the Zhuji coals are higher in Na, K, Be, B, Cr, Co, Se, Sn, Sb, and Bi, but lower in Ti, P, Li, V and Zn. The Zhuji coals are lower only in S, P, V and Zn than average U.S. and world coals. Potassium, Mg, Ca, Mn, Sr, As, Se, Sb and light rare earth elements (LREE) had a tendency to be enriched in thicker coal seams, whereas Fe, Ti, P, V, Co, Ni, Y, Mo, Pb and heavy rare earth elements (HREE) were inclined to concentrate in thinner coal seams. The enrichment of some elements in the Shanxi or Upper Shihezi Formations is related to their depositional environments. The elements are classified into three groups based on their stratigraphic distributions from coal seams 3 to 11-2, and the characteristics of each group are discussed. Lateral distributions of selected elements are also investigated. The correlation coefficients of elemental abundances with ash content show that the elements may be classified into four groups related to modes of occurrence of these elements. ?? 2009 Elsevier B.V. All rights reserved.

  20. Processing of spent Ni-MH batteries for the recovery of cobalt, nickel and rare earth elements bearing materials by means of a chemical and electrochemical sequential process

    NASA Astrophysics Data System (ADS)

    Delvasto, P.; Orta Rodríguez, R.; Blanco, S.

    2016-02-01

    Rechargeable Ni-MH batteries contain strategic metal values which are worth to be recovered. In the present work, a preliminary sequential chemical and electrochemical procedure is proposed, in order to reclaim materials bearing Ni, Co and rare earth elements (REE) from Ni-MH spent batteries. Initially, spent batteries are disassembled to separate the electrode materials (anode and cathode), which are then leached with an aqueous solution of 5w% sulphuric acid. The metal content of this solution is checked by atomic absorption spectrometry techniques. The obtained solution is pH-adjusted (with NaOH), until pH is between 4.0 and 4.3; then, it is heated up to 70°C to precipitate a rare earth elements sulphate (Nd, La, Pr, Ce), as determined by means of x-ray fluorescence techniques. The solids-free solution is then electrolyzed, in order to recover a Ni-Co alloy. The electrolysis conditions were established through a cyclic voltammetry technique.

  1. [Effects of arbuscular mycorrhizal fungi on the growth and rare earth elements uptake of soybean grown in rare earth mine tailings].

    PubMed

    Guo, Wei; Zhao, Ren-xin; Zhao, Wen-jing; Fu, Rui-ying; Guo, Jiang-yuan; Zhang, Jun

    2013-05-01

    A greenhouse pot experiment was conducted to investigate the influence of arbuscular mycorrhizal (AM) fungi Glomus versiforme on the plant growth, nutrient uptake, C: N: P stoichiometric, uptake of heavy metals and rare earth elements by soybean (Glycine max) grown in rare earth mine tailings. The aim was to provide a basis for the revegetation of rare earth mine tailings. The results indicated that soybean had a high mycorrhizal colonization and symbiotic associations were successfully established with G. versiforme, with an average rate of approximately 67%. The colonization of G. versiforme significantly promoted the growth of soybean, increased P, K contents, and decreased C: N: P ratios, supporting the growth rate hypothesis. Inoculation with G. versiforme significantly decreased shoots and roots La, Ce, Pr and Nd concentrations of soybean compared to the control treatment. However, inoculation with G. versiforme had no significant effect on the heavy metal concentrations, except for significantly decreased shoot Fe and Cr concentrations and increased root Cd concentrations. The experiment demonstrates that AM fungi have a potential role for soybean to adapt the composite adversity of rare earth tailings and play a positive role in revegetation of rare earth mine tailings. Further studies on the role of AM fungi under natural conditions should be conducted.

  2. Silver contents and Cu/Ag ratios in Martian meteorites and the implications for planetary differentiation

    NASA Astrophysics Data System (ADS)

    Wang, Zaicong; Becker, Harry

    2017-11-01

    Silver and Cu show very similar partitioning behavior in sulfide melt-silicate melt and metal-silicate systems at low and high pressure-temperature (P-T) experimental conditions, implying that mantle melting, fractional crystallization and core-mantle differentiation have at most modest (within a factor of 3) effects on Cu/Ag ratios. For this reason, it is likely that Cu/Ag ratios in mantle-derived magmatic products of planetary bodies reflect that of the mantle and, in some circumstances, also the bulk planet composition. To test this hypothesis, new Ag mass fractions and Cu/Ag ratios in different groups of Martian meteorites are presented and compared with data from chondrites and samples from the Earth's mantle. Silver contents in lherzolitic, olivine-phyric and basaltic shergottites and nakhlites range between 1.9 and 12.3 ng/g. The data display a negative trend with MgO content and correlate positively with Cu contents. In spite of displaying variable initial Ɛ143Nd values and representing a diverse spectrum of magmatic evolution and physiochemical conditions, shergottites and nakhlites display limited variations of Cu/Ag ratios (1080 ± 320, 1 s, n = 14). The relatively constant Cu/Ag suggests limited fractionation of Ag from Cu during the formation and evolution of the parent magmas, irrespectively of whether sulfide saturation was attained or not. The mean Cu/Ag ratio of Martian meteorites thus reflects that of the Martian mantle and constrains its Ag content to 1.9 ± 0.7 ng/g (1 s). Carbonaceous and enstatite chondrites display a limited range of Cu/Ag ratios of mostly 500-2400. Ordinary chondrites show a larger scatter of Cu/Ag up to 4500, which may have been caused by Ag redistribution during parent body metamorphism. The majority of chondrites have Cu/Ag ratios indistinguishable from the Martian mantle value, indicating that Martian core formation strongly depleted Cu and Ag contents, but probably did not significantly change the Cu/Ag ratio of the mantle compared to bulk Mars. Bulk Mars is richer in moderately volatile elements than Earth, however, the Martian mantle displays a much stronger depletion of the moderately volatile elements Cu and Ag, e.g., by a factor of 15 for Cu. This observation is consistent with experimental studies suggesting that core formation at low P-T conditions on Mars led to more siderophile behavior of Cu and Ag than at high P-T conditions as proposed for Earth. In contrast, Cu/Ag ratios of the mantles of Mars and Earth (Cu/AgEarth = 3500 ± 1000) display only a difference by a factor of 3, which implies restricted fractionation of Cu and Ag even at high P-T conditions. The concentration data support the notion that siderophile element partitioning during planetary core formation scales with the size of the planetary body, which is particularly important for the differentiation of large terrestrial planets such as Earth. Collectively, the Ag and Cu data on magmatic products from the mantles of Mars and Earth and the data on chondrites confirm experimental predictions and support the limited fractionation of Cu and Ag during planetary core formation and high-temperature magmatic evolution, and probably also in early solar nebular processes.

  3. Grouping Minerals by Their Formulas

    ERIC Educational Resources Information Center

    Mulvey, Bridget

    2018-01-01

    Minerals are commonly taught in ways that emphasize mineral identification for its own sake or maybe to help identify rocks. But how do minerals fit in with other science content taught? The author uses mineral formulas to help Earth science students wonder about the connection between elements, compounds, mixtures, minerals, and mineral formulas.…

  4. Publications - AR 2010-C | Alaska Division of Geological & Geophysical

    Science.gov Websites

    Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska content DGGS AR 2010-C Publication Details Title: Engineering Geology FY11 project descriptions Authors , Engineering Geology FY11 project descriptions, in DGGS Staff, Alaska Division of Geological & Geophysical

  5. Differentiation of the matter of the moon

    NASA Technical Reports Server (NTRS)

    Vinogradov, A. P.

    1977-01-01

    The following facts were uncovered in comparing the basaltic surface rocks of the moon with terrestrial tholeiitic basalts and ordinary chondrites: (1) there is an excess of the so-called refractory chemical elements, including the group of truly refractory elements, the rare earths, U, and Th, in comparison with their content in primitive terrestrial basalts and chondrites; (2) the so-called siderophilic elements have lower contents in the lunar surface rocks than in terrestrial rocks; (3) the low alkali content (Na, K, Rb) in lunar rocks is established; (4) there is a low content of H2O and the ordinary gases CO2, halides, etc.; (5) the low content of metals with high vapor pressure, (In, Tl, etc.) has been established. It is proposed that U and Th were carried from the internal areas to the peripheral rocks of the moon during magmatic activity, i.e., up to 3 billion years ago. This redistribution of U and Th lead to their concentration in surface layers of the moon, and the heat which they generated was lost into surrounding space. The conclusion is then reached that in order to understand processes on the moon, the chondritic model cannot be used.

  6. Planktonic foraminiferal rare earth elements as a potential new aeolian dust proxy

    NASA Astrophysics Data System (ADS)

    Chou, C.; Liu, Y.; Lo, L.; Wei, K.; Shen, C.

    2012-12-01

    Characteristics of rare earth elements (REEs) have widely been used as important tracers in many fields of earth sciences, including lithosphere research, environmental change, ocean circulation and other natural carbonate materials. Foraminiferal test REE signatures have been suggested to reflect ambient seawater conditions and serve as valuable proxies in the fields of paleoceanography and paleoclimate. Here we present a 60-kyr planktonic foraminifera Globigerinoides ruber (white, 250-300 μm) REE record of a sediment core MD05-2925 (9°20.61'S, 151°27.61'E, water depth 1660 m) from the Solomon Sea. The REE diagram shows two dominant sources of local seawater and nearby terrestrial input. The variability of foraminiferal REE/Ca time series is different from Mg/Ca-inferred sea surface temperature and δ18O records during the past 60-kyr. This inconsistency suggests that planktonic foraminiferal REE content cannot result only from changes in ice volume and temperature. Synchroneity between high planktonic foraminiferal REE content and Antarctic ice core dust amount record implies the same dust sources, probably from Australia or mainland China. Our results suggest that foraminiferal REE can potentially be as a new dust proxy and record dry/humid conditions at the source area.

  7. Mineral resource of the month: rare earth elements

    USGS Publications Warehouse

    ,

    2011-01-01

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

  8. Low hydrogen contents in the cores of terrestrial planets.

    PubMed

    Clesi, Vincent; Bouhifd, Mohamed Ali; Bolfan-Casanova, Nathalie; Manthilake, Geeth; Schiavi, Federica; Raepsaet, Caroline; Bureau, Hélène; Khodja, Hicham; Andrault, Denis

    2018-03-01

    Hydrogen has been thought to be an important light element in Earth's core due to possible siderophile behavior during core-mantle segregation. We reproduced planetary differentiation conditions using hydrogen contents of 450 to 1500 parts per million (ppm) in the silicate phase, pressures of 5 to 20 GPa, oxygen fugacity varying within IW-3.7 and IW-0.2 (0.2 to 3.7 log units lower than iron-wüstite buffer), and Fe alloys typical of planetary cores. We report hydrogen metal-silicate partition coefficients of ~2 × 10 -1 , up to two orders of magnitude lower than reported previously, and indicative of lithophile behavior. Our results imply H contents of ~60 ppm in the Earth and Martian cores. A simple water budget suggests that 90% of the water initially present in planetary building blocks was lost during planetary accretion. The retained water segregated preferentially into planetary mantles.

  9. Towards the development of new phosphors with reduced content of rare earth elements: Structural and optical characterization of Ce:Tb: Al{sub 2}SiO{sub 5}

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chiriu, D.; Stagi, L.; Carbonaro, C.M.

    2016-05-15

    Highlights: • A new promising inert matrix as host of luminescent ions is proposed. • Al2SiO5 matrix is free from Rare earths (critical raw materials). • Doping the matrix with Ce and Tb we obtain an efficient green emitter. • Cerium acts as sensitizer for Terbium emission. - Abstract: A new promising inert matrix as host of luminescent ions is proposed. Al2SiO5 samples, doped with rare earths (Ce, Tb single doped and co-doped) are proposed as good prospect for the development of new UV–vis converter with reduced content of rare earths elements. Structural characterization by Raman, XRD spectroscopy and TEMmore » imaging reveals the sillimanite phase and nano sized dimension of the investigated powders. Optical characterization by steady time and time resolved emission spectroscopy for the single doped and co-doped samples allows to identify an efficient energy transfer from Ce to Tb ions under near UV excitation wavelength. The intense green emission observed in the Ce:Tb co-doped Al2SiO5 system suggests its potential application as efficient blue pumped green emitter phosphor to be exploited for white LED: to this purpose we tested the compound in combination with a red emitting doping ion recording for Ce:Tb:Cr:ASO system a correlated color temperature of 6720 K.« less

  10. Rare earth elements in German soils - A review.

    PubMed

    Mihajlovic, Julia; Rinklebe, Jörg

    2018-08-01

    Rare earth elements (REEs) are increasingly used in high-tech industry, agriculture, and healthcare technologies what leads to their release into soils and waters, and to the transfer into plants what may have negative impacts on human health and the environment. The toxicity and potential mobilization of REEs in soils can be assessed by their content and geochemical behavior along with soil properties. However, those interactions are so far not reviewed in German soils although such a review is important for a better understanding and prediction of the potential mobilization and toxicity. Therefore, this review summarizes the recent knowledge about REE contents and potential mobilization in different soil profiles in Germany. We found that the REE content tends to decrease in dependence on the parent material in the following order: Carbonatite > basalt > orthogneiss > clay slate > loess > sandstone > Pleistocene and Holocene sediments > organic material. Also, we used data of earlier studies, summarized and newly evaluated those data aiming to quantify the factors influencing the total REE content in German soil profiles. The contents of REEs in soil profiles of different parent material showed significant relations with content of clay, carbonate, organic matter, aluminium, iron, and manganese. Geochemical fractionation results suggest that the bioavailability of REEs is relatively low while the residual fraction is relatively high in German soils. In soils, where water fluctuations are important, the redox potential is a key factor controlling the mobilization of REEs also via related changes of pH. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Evaporative fractionation of volatile stable isotopes and their bearing on the origin of the Moon.

    PubMed

    Day, James M D; Moynier, Frederic

    2014-09-13

    The Moon is depleted in volatile elements relative to the Earth and Mars. Low abundances of volatile elements, fractionated stable isotope ratios of S, Cl, K and Zn, high μ ((238)U/(204)Pb) and long-term Rb/Sr depletion are distinguishing features of the Moon, relative to the Earth. These geochemical characteristics indicate both inheritance of volatile-depleted materials that formed the Moon and planets and subsequent evaporative loss of volatile elements that occurred during lunar formation and differentiation. Models of volatile loss through localized eruptive degassing are not consistent with the available S, Cl, Zn and K isotopes and abundance data for the Moon. The most probable cause of volatile depletion is global-scale evaporation resulting from a giant impact or a magma ocean phase where inefficient volatile loss during magmatic convection led to the present distribution of volatile elements within mantle and crustal reservoirs. Problems exist for models of planetary volatile depletion following giant impact. Most critically, in this model, the volatile loss requires preferential delivery and retention of late-accreted volatiles to the Earth compared with the Moon. Different proportions of late-accreted mass are computed to explain present-day distributions of volatile and moderately volatile elements (e.g. Pb, Zn; 5 to >10%) relative to highly siderophile elements (approx. 0.5%) for the Earth. Models of early magma ocean phases may be more effective in explaining the volatile loss. Basaltic materials (e.g. eucrites and angrites) from highly differentiated airless asteroids are volatile-depleted, like the Moon, whereas the Earth and Mars have proportionally greater volatile contents. Parent-body size and the existence of early atmospheres are therefore likely to represent fundamental controls on planetary volatile retention or loss. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  12. Trace element and strontium isotope characteristics of volcanic rocks from Isla Tortuga: a young seamount in the Gulf of California

    USGS Publications Warehouse

    Batiza, Rodey; Futa, K.; Hedge, C.E.

    1979-01-01

    Isla Tortuga is a small isolated central volcano which is located near an actively spreading trough in the Gulf of California. The basalt lavas from Tortuga which have the highest Mg/Fe and Ni contents have trace element abundances and ratios and 87Sr/86Sr which are similar to those of mid-ocean ridge tholeiite. The major element, rare earth element and Sr abundances of fractionated tholeiite (low Mg/Fe) and tholeiitic andesite of Tortuga are consistent with an origin by closed-system fractional crystallization. This hypothesis is not supported by K, Na, Rb and Ba abundances in the lavas nor by their variable 87Sr/86Sr (0.7024-0.7035). It is proposed that the apparent decoupling of light rare earth elements, other incompatible trace elements and 87Sr/86Sr is due to contamination of some Tortuga magmas while they are fractionated in a high-level crustal magma chamber. The mantle source of least-contaminated, high Mg/Fe basalt lavas of Tortuga is similar, although not identical to the source of normal mid-ocean ridge tholeiite; significant differences exist. The reasons for these differences are not yet known. ?? 1979.

  13. Publications - RDF 2015-5 | Alaska Division of Geological & Geophysical

    Science.gov Websites

    Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska

  14. Publications - RI 2009-2 | Alaska Division of Geological & Geophysical

    Science.gov Websites

    Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska

  15. Publications - MP 142 | Alaska Division of Geological & Geophysical Surveys

    Science.gov Websites

    Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Surveys Home Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska Tidal Datum

  16. Publications - RDF 2016-3 | Alaska Division of Geological & Geophysical

    Science.gov Websites

    Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska

  17. Publications - SR 70 | Alaska Division of Geological & Geophysical Surveys

    Science.gov Websites

    Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Surveys Home Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska Tidal Datum

  18. Presentations - Twelker, Evan and Lande, Lauren, 2015 | Alaska Division of

    Science.gov Websites

    Geological & Geophysical Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of (AVO) Mineral Resources Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem

  19. Publications - MP 38 | Alaska Division of Geological & Geophysical Surveys

    Science.gov Websites

    Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Surveys Home Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska Tidal Datum

  20. Publications - SR 45 | Alaska Division of Geological & Geophysical Surveys

    Science.gov Websites

    Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Surveys Home Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska Tidal Datum

  1. Publications - RDF 2016-5 | Alaska Division of Geological & Geophysical

    Science.gov Websites

    Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska

  2. Publications - MP 43 | Alaska Division of Geological & Geophysical Surveys

    Science.gov Websites

    Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Surveys Home Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska Tidal Datum

  3. Publications - MP 149 | Alaska Division of Geological & Geophysical Surveys

    Science.gov Websites

    Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Surveys Home Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska Tidal Datum

  4. Publications - RDF 2014-22 | Alaska Division of Geological & Geophysical

    Science.gov Websites

    Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska

  5. Presentations - Wypych, Alicja and others, 2015 | Alaska Division of

    Science.gov Websites

    Geological & Geophysical Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of (AVO) Mineral Resources Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem

  6. Publications - RDF 2000-4 | Alaska Division of Geological & Geophysical

    Science.gov Websites

    Oxides; Palladium; Platinum; Rare Earth Elements; STATEMAP Project; Trace Metals Top of Page Department Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

  7. Publications - AR 2011-C | Alaska Division of Geological & Geophysical

    Science.gov Websites

    Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska content DGGS AR 2011-C Publication Details Title: Engineering Geology FY12 project descriptions Authors Combellick, R.A., 2012, Engineering Geology FY12 project descriptions, in DGGS Staff, Alaska Division of

  8. The earth's oldest known crust - A geochronological and geochemical study of 3900-4200 Ma old detrital zircons from Mt. Narryer and Jack Hills, Western Australia

    NASA Astrophysics Data System (ADS)

    Maas, Roland; Kinny, Peter D.; Williams, Ian S.; Froude, Derek O.; Compston, William

    1992-03-01

    Trace element characteristics were analyzed and inclusions were identified within a suite of pre-3.9 Ga detritral zircons from western Australia representing the earth's oldest-known minerals. A diversity of trace-element compositions was found, particularly in the REE compositions of the old Mt. Narryer zircons, implying a variety of source-rock compositions and hence, the presence of a differentiated crust in the earth 4.15-4.20 Ga ago. Comparisons drawn with data obtained from younger detrital zircons occurring within the same deposits indicate nothing unique about the chemical compositions of the old grains. A number of interelement covariations were observed among the analyzed grains which were independent of age and isotopic characteristics, most notably that occurring between Lu and Hf. A general positive correlation between total LREE and the U + Th contents is also apparent. The findings indicate an origin in felsic igneous rocks, which has implications for early-Archaean crustal evolution.

  9. Magnetic Nanofluid Rare Earth Element Extraction Process Report, Techno Economic Analysis, and Results for Geothermal Fluids

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pete McGrail

    This GDR submission is an interim technical report and raw data files from the first year of testing on functionalized nanoparticles for rare earth element extraction from geothermal fluids. The report contains Rare Earth Element uptake results (percent removal, mg Rare Earth Element/gram of sorbent, distribution coefficient) for the elements of Neodymium, Europium, Yttrium, Dysprosium, and Cesium. A detailed techno economic analysis is also presented in the report for a scaled up geothermal rare earth element extraction process. All rare earth element uptake testing was done on simulated geothermal brines with one rare earth element in each brine. The raremore » earth element uptake testing was conducted at room temperature.« less

  10. Reconstructing mantle volatile contents through the veil of degassing

    NASA Astrophysics Data System (ADS)

    Tucker, J.; Mukhopadhyay, S.; Gonnermann, H. M.

    2014-12-01

    The abundance of volatile elements in the mantle reveals critical information about the Earth's origin and evolution such as the chemical constituents that built the Earth and material exchange between the mantle and exosphere. However, due to magmatic degassing, volatile element abundances measured in basalts usually do not represent those in undegassed magmas and hence in the mantle source of the basalts. While estimates of average mantle concentrations of some volatile species can be obtained, such as from the 3He flux into the oceans, volatile element variability within the mantle remains poorly constrained. Here, we use CO2-He-Ne-Ar-Xe measurements in basalts and a new degassing model to reconstruct the initial volatile contents of 8 MORBs from the Mid-Atlantic Ridge and Southwest Indian Ridge that span a wide geochemical range from depleted to enriched MORBs. We first show that equilibrium degassing (e.g. Rayleigh degassing), cannot simultaneously fit the measured CO2-He-Ne-Ar-Xe compositions in MORBs and argue that kinetic fractionation between bubbles and melt lowers the dissolved ratios of light to heavy noble gas species in the melt from that expected at equilibrium. We present a degassing model (after Gonnermann and Mukhopadhyay, 2007) that explicitly accounts for diffusive fractionation between melt and bubbles. The model computes the degassed composition based on an initial volatile composition and a diffusive timescale. To reconstruct the undegassed volatile content of a sample, we find the initial composition and degassing timescale which minimize the misfit between predicted and measured degassed compositions. Initial 3He contents calculated for the 8 MORB samples vary by a factor of ~7. We observe a correlation between initial 3He and CO2 contents, indicating relatively constant CO2/3He ratios despite the geochemical diversity and variable gas content in the basalts. Importantly, the gas-rich popping rock from the North Atlantic, as well as the average mantle ratio computed from the ridge 3He flux and independently estimated CO2 content fall along the same correlation. This observation suggests that undegassed CO2 and noble gas concentrations can be reconstructed in individual samples through measurement of noble gases and CO2 in erupted basalts.

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

    PubMed

    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.

  12. Geochemical variations of rare earth elements in Marcellus shale flowback waters and multiple-source cores in the Appalachian Basin

    NASA Astrophysics Data System (ADS)

    Noack, C.; Jain, J.; Hakala, A.; Schroeder, K.; Dzombak, D. A.; Karamalidis, A.

    2013-12-01

    Rare earth elements (REE) - encompassing the naturally occurring lanthanides, yttrium, and scandium - are potential tracers for subsurface groundwater-brine flows and geochemical processes. Application of these elements as naturally occurring tracers during shale gas development is reliant on accurate quantitation of trace metals in hypersaline brines. We have modified and validated a liquid-liquid technique for extraction and pre-concentration of REE from saline produced waters from shale gas extraction wells with quantitative analysis by ICP-MS. This method was used to analyze time-series samples of Marcellus shale flowback and produced waters. Additionally, the total REE content of core samples of various strata throughout the Appalachian Basin were determined using HF/HNO3 digestion and ICP-MS analysis. A primary goal of the study is to elucidate systematic geochemical variations as a function of location or shale characteristics. Statistical testing will be performed to study temporal variability of inter-element relationships and explore associations between REE abundance and major solution chemistry. The results of these analyses and discussion of their significance will be presented.

  13. Pyrometallurgical Extraction of Valuable Elements in Ni-Metal Hydride Battery Electrode Materials

    NASA Astrophysics Data System (ADS)

    Jiang, Yin-ju; Deng, Yong-chun; Bu, Wen-gang

    2015-10-01

    Gas selective reduction-oxidation (redox) and melting separation were consecutively applied to electrode materials of AB5-type Ni-metal hydride batteries leading to the production of a Ni-Co alloy and slag enriched with rare earth oxides (REO). In the selective redox process, electrode materials were treated with H2/H2O at 1073 K and 1173 K (800 °C and 900 °C). Active elements such as REs, Al, and Mn were oxidized whereas relatively inert elements such as Ni and Co were transformed into their elemental states in the treated materials. SiO2 and Al2O3 powders were added into the treated materials as fluxes which were then melted at 1823 K (1550 °C) to yield a Ni-Co alloy and a REO-SiO2-Al2O3-MnO slag. The high-purity Ni-Co alloy produced can be used as a raw material for AB5-type hydrogen-storage alloy. The REO content in slag was very high, i.e., 48.51 pct, therefore it can be used to recycle rare earth oxides.

  14. [An investigation of lanthanum and other metals levels in blood, urine and hair among residents in the rare earth mining area of a city in China].

    PubMed

    Bao, T M; Tian, Y; Wang, L X; Wu, T; Lu, L N; Ma, H Y; Wang, L

    2018-02-20

    Objective: To investigate the levels of lanthanum, cerium, praseodymium, and neodymium in the blood, urine, and hair samples from residents in the rare earth mining area of a city in China, and to provide a scientific basis for the control of rare earth pollution and the protection of population health. Methods: A total of 147 residents who had lived in the rare earth mining area of a city for a long time were selected as the exposure group, and 108 residents in Guyang County of this city who lived 91 km away from the rare earth mining area were selected as the control group. Blood, urine, and hair samples were collected from the residents in both groups. Inductively coupled plasma mass spectrometry was used to determine the content of lanthanum, cerium, praseodymium, and neodymium in blood, urine, and hair samples. Results: In the exposure group, the median levels of lanthanum, cerium, praseodymium, and neodymium were 0.854, 1.724, 0.132, and 0.839 μg/L, respectively, in blood samples, 0.420, 0.920, 0.055, and 0.337 μg/L, respectively, in urine samples, and 0.052, 0.106, 0.012, and 0.045 μg/g, respectively, in hair samples. The exposure group had significantly higher levels of the four rare earth elements in blood, urine, and hair samples than the control group ( P <0.01) . Conclusion: The residents in the rare earth mining area of this city have higher content of lanthanum, cerium, praseodymium, and neodymium in blood, urine, and hair than those in the non-mining area; the content of cerium is highest, followed by lanthanum, neodymium, and praseodymium.

  15. Melting of Fe-Si-O alloys: the Fate of Coexisting Si and O in the Core

    NASA Astrophysics Data System (ADS)

    Arveson, S. M.; Lee, K. K. M.

    2017-12-01

    The light element budget of Earth's core plays an integral role in sustaining outer core convection, which powers the geodynamo. Many experiments have been performed on binary iron compounds, but the results do not robustly agree with seismological observations and geochemical constraints. Earth's core is almost certainly made up of multiple light elements, so the future of core composition studies lies in ternary (or higher order) systems in order to examine interactions between light elements. We perform melting experiments on Fe-Si-O alloys in a laser-heated diamond-anvil cell to 80 GPa and 4000 K. Using 2D multi- wavelength imaging radiometry together with textural and chemical analysis of quenched samples, we measure the high-pressure melting curves and determine partitioning of light elements between the melt and the coexisting solid. Quenched samples are analyzed both in map view and in cross section using scanning electron microscopy (SEM) and electron microprobe analysis (EPMA) to examine the 3D melt structure and composition. Partitioning of light elements between molten and solid alloys dictates (1) the density contrast at the ICB, which drives compositional convection in the outer core and (2) the temperature of the CMB, an integral parameter for understanding the deep Earth. Our experiments suggest silicon and oxygen do not simply coexist in the melt and instead show complex solubility based on temperature. Additionally, we do not find evidence of crystallization of SiO2 at low oxygen content as was recently reported.11 Hirose, K., et al., Crystallization of silicon dioxide and compositional evolution of the Earth's core. Nature, 2017. 543(7643): p. 99-102.

  16. Test and Verification Approach for the NASA Constellation Program

    NASA Technical Reports Server (NTRS)

    Strong, Edward

    2008-01-01

    This viewgraph presentation is a test and verification approach for the NASA Constellation Program. The contents include: 1) The Vision for Space Exploration: Foundations for Exploration; 2) Constellation Program Fleet of Vehicles; 3) Exploration Roadmap; 4) Constellation Vehicle Approximate Size Comparison; 5) Ares I Elements; 6) Orion Elements; 7) Ares V Elements; 8) Lunar Lander; 9) Map of Constellation content across NASA; 10) CxP T&V Implementation; 11) Challenges in CxP T&V Program; 12) T&V Strategic Emphasis and Key Tenets; 13) CxP T&V Mission & Vision; 14) Constellation Program Organization; 15) Test and Evaluation Organization; 16) CxP Requirements Flowdown; 17) CxP Model Based Systems Engineering Approach; 18) CxP Verification Planning Documents; 19) Environmental Testing; 20) Scope of CxP Verification; 21) CxP Verification - General Process Flow; 22) Avionics and Software Integrated Testing Approach; 23) A-3 Test Stand; 24) Space Power Facility; 25) MEIT and FEIT; 26) Flight Element Integrated Test (FEIT); 27) Multi-Element Integrated Testing (MEIT); 28) Flight Test Driving Principles; and 29) Constellation s Integrated Flight Test Strategy Low Earth Orbit Servicing Capability.

  17. Rare earth elements: end use and recyclability

    USGS Publications Warehouse

    Goonan, Thomas G.

    2011-01-01

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

  18. Long Duration Space Missions: Human Subsystem Risks and Requirements

    NASA Technical Reports Server (NTRS)

    Kundrot, Criag E.

    2011-01-01

    This viewgraph presentation reviews the human health and performance risks associated with long duration space flight beyond low earth orbit. The contents include: 1) Human Research Program; 2) Human Subsystem Risks; 3) Human Exploration Framework Team (HEFT) Architecture Elements; 4) Potentially Unacceptable Risks -1; 5) Potentially Unacceptable Risks-2; and 6) Major Mission Drivers of Risk.

  19. Publications - GMC 410 | Alaska Division of Geological & Geophysical

    Science.gov Websites

    ) Keywords Geochemistry; Rare Earth Elements Top of Page Department of Natural Resources, Division of Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

  20. Publications - RDF 2008-2 v. 1.0.1 | Alaska Division of Geological &

    Science.gov Websites

    Geophysical Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska

  1. Publications - GMC 409 | Alaska Division of Geological & Geophysical

    Science.gov Websites

    ) Keywords Geochemistry; Rare Earth Elements Top of Page Department of Natural Resources, Division of Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

  2. Bibliography of Soviet Laser Developments, Number 77, May - June 1985.

    DTIC Science & Technology

    1986-09-01

    B . CONTRACT OR GRANT NUMBER(S) 9. PERFORMING ORGANIZATION NAME AND ADDRESS I0. PROGRAM ELEMENT. PROJECT, TASK Defense Intelligence Agency AREA...TABLE OF CONTENTS I. BASIC RESEARCH A. Solid State Lasers 1. Crystal a. Miscellaneous ................... 1 b . Ruby .. . . . . . . .. . . . . . - c...LiF ............................. 1 2. Rare Earth a. Miscellaneous .......... .. . 1 b . Nd3+ . .. . . . .. . .0 . . . . c. Er3

  3. Rare earth elements in fine-grained sediments of major rivers from the high-standing island of Taiwan

    NASA Astrophysics Data System (ADS)

    Li, Chuan-Shun; Shi, Xue-Fa; Kao, Shuh-Ji; Liu, Yan-Guang; Lyu, Hua-Hua; Zou, Jian-Jun; Liu, Sheng-Fa; Qiao, Shu-Qing

    2013-06-01

    Thirty-eight sediment samples from 15 primary rivers on Taiwan were retrieved to characterize the rare earth element (REE) signature of fluvial fine sediment sources. Compared to the three large rivers on the Chinese mainland, distinct differences were observed in the REE contents, upper continental crust normalized patterns and fractionation factors of the sediment samples. The average REE concentrations of the Taiwanese river sediments are higher than those of the Changjiang and Huanghe, but lower than the Zhujiang. Light rare earth elements (LREEs) are enriched relative to heavy rare earth elements (HREEs) with ratios from 7.48 to 13.03. We found that the variations in (La/Lu)UCC-(Gd/Lu)UCC and (La/Yb)UCC-(Gd/Yb)UCC are good proxies for tracing the source sediments of Taiwanese and Chinese rivers due to their distinguishable values. Our analyses indicate that the REE compositions of Taiwanese river sediments were primarily determined by the properties of the bedrock, and the intensity of chemical weathering in the drainage areas. The relatively high relief and heavy rainfall also have caused the REEs in the fluvial sediments from Taiwan to be transported to the estuaries down rivers from the mountains, and in turn delivered nearly coincidently to the adjacent seas by currents and waves. Our studies suggest that the REE patterns of the river sediments from Taiwan are distinguishable from those from the other sources of sediments transported into the adjacent seas, and therefore are useful proxies for tracing the provenances and dispersal patterns of sediments, as well as paleoenvironmental changes in the marginal seas.

  4. Asteroidal impacts and the origin of terrestrial and lunar volatiles

    NASA Astrophysics Data System (ADS)

    Albarede, Francis; Ballhaus, Chris; Blichert-Toft, Janne; Lee, Cin-Ty; Marty, Bernard; Moynier, Frédéric; Yin, Qing-Zhu

    2013-01-01

    Asteroids impacting the Earth partly volatilize, partly melt (O'Keefe, J.D., Ahrens, T.J. [1977]. Proc. Lunar Sci. Conf. 8, 3357-3374). While metal rapidly segregates out of the melt and sinks into the core, the vaporized material orbits the Earth and eventually rains back onto its surface. The content of the mantle in siderophile elements and their chondritic relative abundances hence is accounted for, not by the impactors themselves, as in the original late-veneer model (Chou, C.L. [1978]. Proc. Lunar Sci. Conf. 9, 219-230; Morgan, J.W. et al. [1981]. Tectonophysics 75, 47-67), but by the vapor resulting from impacts. The impactor's non-siderophile volatiles, notably hydrogen, are added to the mantle and hydrosphere. The addition of late veneer may have lasted for 130 Ma after isolation of the Solar System and probably longer, i.e., well beyond the giant lunar impact. Constraints from the stable isotopes of oxygen and other elements suggest that, contrary to evidence from highly siderophile elements, ˜4% of CI chondrites accreted to the Earth. The amount of water added in this way during the waning stages of accretion, and now dissolved in the deep mantle or used to oxidize Fe in the mantle and the core, may correspond to 10-25 times the mass of the present-day ocean. The Moon is at least 100 times more depleted than the Earth in volatile elements with the exception of some isolated domains, such as the mantle source of 74220 pyroclastic glasses, which appear to contain significantly higher concentrations of water and other volatiles.

  5. Photon interaction studies using 241Am g-rays

    NASA Astrophysics Data System (ADS)

    Ramachandran, N.; Karunakaran Nair, K.; Abdullah, K. K.; Varier, K. M.

    2006-09-01

    We have carried out some photon interaction measurements using 59.54 keV γ-rays from a ^{241}Am source. These include γ attenuation studies as well as photoelectric absorption studies in various samples. The attenuation studies have been made using leaf and wood samples, samples like sand, sugar etc., which contain particles of varying sizes as well as pellets and aqueous solutions of rare earth compounds. In the case of the leaf and wood samples, we have used the γ-ray attenuation technique for the determination of the water content in fresh and dried samples. The variation of the attenuation coefficient with particle size has been investigated for sand and sugar samples. The attenuation studies as well as the photoelectric studies in the case of rare earth elements have been carried out on samples containing such elements whose K-absorption edge energies lie below and close to the γ-energy used. Suitable compounds of the rare earth elements have been chosen as mixture absorbers in these investigations. A narrow beam good geometry set-up was used for the attenuation measurements. A well-shielded scattering geometry was used for the photoelectric measurements. The mixture rule was invoked to extract the values of the mass attenuation coefficients for the elements from those of the corresponding compounds. The results are consistent with theoretical values derived from the XCOM package.

  6. Sources and distribution of yttrium and rare earth elements in surface sediments from Tagus estuary, Portugal.

    PubMed

    Brito, Pedro; Prego, Ricardo; Mil-Homens, Mário; Caçador, Isabel; Caetano, Miguel

    2018-04-15

    The distribution and sources of yttrium and rare-earth elements (YREE) in surface sediments were studied on 78 samples collected in the Tagus estuary (SW Portugal, SW Europe). Yttrium and total REE contents ranged from 2.4 to 32mg·kg -1 and 18 to 210mg·kg -1 , respectively, and exhibited significant correlations with sediment grain-size, Al, Fe, Mg and Mn, suggesting a preferential association to fine-grained material (e.g. aluminosilicates but also Al hydroxides and Fe oxyhydroxides). The PAAS (Post-Archean Australian Shale) normalized patterns display three distinct YREE fractionation pattern groups along the Tagus estuary: a first group, characterized by medium to coarse-grained material, a depleted and almost flat PAAS-normalized pattern, with a positive anomaly of Eu, representing one of the lithogenic components; a second group, characterized mainly by fine-grained sediment, with higher shale-normalized ratios and an enrichment of LREE relative to HREE, associated with waste water treatment plant (WWTP) outfalls, located in the northern margin; and, a third group, of fine-grained material, marked by a significant enrichment of Y, a depletion of Ce and an enrichment of HREE over LREE, located near an inactive chemical-industrial complex (e.g. pyrite roast plant, chemical and phosphorous fertilizer industries), in the southern margin. The data allow the quantification of the YREE contents and its spatial distribution in the surface sediments of the Tagus estuary, identifying the main potential sources and confirming the use of rare earth elements as tracers of anthropogenic activities in highly hydrodynamic estuaries. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    NASA Astrophysics Data System (ADS)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman

    2014-02-01

    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) & 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) &29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of 232Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.

  8. A hydrometallurgical process for the recovery of terbium from fluorescent lamps: Experimental design, optimization of acid leaching process and process analysis.

    PubMed

    Innocenzi, Valentina; Ippolito, Nicolò Maria; De Michelis, Ida; Medici, Franco; Vegliò, Francesco

    2016-12-15

    Terbium and rare earths recovery from fluorescent powders of exhausted lamps by acid leaching with hydrochloric acid was the objective of this study. In order to investigate the factors affecting leaching a series of experiments was performed in according to a full factorial plan with four variables and two levels (4 2 ). The factors studied were temperature, concentration of acid, pulp density and leaching time. Experimental conditions of terbium dissolution were optimized by statistical analysis. The results showed that temperature and pulp density were significant with a positive and negative effect, respectively. The empirical mathematical model deducted by experimental data demonstrated that terbium content was completely dissolved under the following conditions: 90 °C, 2 M hydrochloric acid and 5% of pulp density; while when the pulp density was 15% an extraction of 83% could be obtained at 90 °C and 5 M hydrochloric acid. Finally a flow sheet for the recovery of rare earth elements was proposed. The process was tested and simulated by commercial software for the chemical processes. The mass balance of the process was calculated: from 1 ton of initial powder it was possible to obtain around 160 kg of a concentrate of rare earths having a purity of 99%. The main rare earths elements in the final product was yttrium oxide (86.43%) following by cerium oxide (4.11%), lanthanum oxide (3.18%), europium oxide (3.08%) and terbium oxide (2.20%). The estimated total recovery of the rare earths elements was around 70% for yttrium and europium and 80% for the other rare earths. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Influence of soil characteristics on rare earth fingerprints in mosses and mushrooms: Example of a pristine temperate rainforest (Slavonia, Croatia).

    PubMed

    Fiket, Željka; Medunić, Gordana; Furdek Turk, Martina; Ivanić, Maja; Kniewald, Goran

    2017-07-01

    The present study aims to investigate levels and distribution of rare earth elements (REE) in soils, mosses and mushrooms of a pristine temperate rainforest, a non-polluted natural system, in order to characterise their environmental availability and mobility. The multielement analysis of digested soil, moss and mushroom samples was performed by High Resolution Inductively Coupled Plasma Mass Spectrometry. The distribution of rare earths in mosses and mushrooms was found primarily affected by local pedological setting. Mosses displayed a consistent lithological signature with an almost insignificant REE fractionation compared to soils. Mushrooms showed differences in REE concentrations in certain parts of the fruiting body with regard to their main physiological function and indicated a significant impact of soil organic content on the overall REEs uptake. Results of our work highlight the importance of substrate characteristics on the initial levels of REEs in mosses and mushrooms. Moreover, this study provides baseline data on the rare earth element levels in mosses and mushrooms growing in a pristine forest area characterised by naturally elevated REE levels in the soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Depletions of sulfur and/or zinc in IDPs: Are they reliable indicators of atmospheric entry heating?

    NASA Technical Reports Server (NTRS)

    Flynn, G. J.; Sutton, S. R.; Bajt, S.; Kloeck, W.; Thomas, K. L.; Keller, L. P.

    1993-01-01

    The degree of heating of interplanetary dust particles (IDP's) on Earth atmospheric entry is important in distinguishing cometary particles from main-belt asteroidal particles. Depletions in the volatile elements S and Zn were proposed as chemical indicators of significant entry heating. The S and Zn contents of cosmic dust particles were correlated with physical indicators of atmospheric entry heating, such as the production of magnetite and the loss of solar wind implanted He. The results indicate that the Zn content of IDP's is a useful indicator of entry heating, but the S content seems to be less useful.

  11. Distribution characteristics of rare earth elements in children's scalp hair from a rare earths mining area in southern China.

    PubMed

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

    2004-01-01

    In order to demonstrate the validity of using scalp hair rare earth elements (REEs) content as a biomarker of human REEs exposure, data were collected on REEs exposure levels from children aged 11-15 years old and living in an ion-adsorptive type light REEs (LREEs) mining and surrounding areas in southern China. Sixty scalp hair samples were analyzed by ICP-MS for 16 REEs (La Lu, Y and Sc). Sixteen REEs contents in the samples from the mining area (e.g., range: La: 0.14-6.93 microg/g; Nd: 0.09-5.27 microg/g; Gd: 12.2-645.6ng/g; Lu: 0.2-13.3 ng/g; Y: 0.03-1.27 microg/g; Sc: 0.05-0.30 microg/g) were significantly higher than those from the reference area (range: La: 0.04-0.40 microg/g; Nd: 0.04-0.32 microg/g; Gd: 8.3-64.6 ng/g; Lu: 0.4-3.3ng/g; Y: 0.03-0.29 microg/g; Sc: 0.11-0.36 microg/g) and even much higher than those published in the literature. The distribution pattern of REEs in scalp hair from the mining area was very similar to that of REEs in the mine and the atmosphere shrouding that area. In conclusion, the scalp hair REEs contents may indicate not only quantitatively but also qualitatively (distribution pattern) the absorption of REEs from environmental exposure into human body. The children living in this mining area should be regarded as a high-risk group with REEs (especially LREEs) exposure, and their health status should be examined from a REEs health risk assessment perspective.

  12. Marine phosphorites as potential resources for heavy rare earth elements and yttrium

    USGS Publications Warehouse

    Hein, James; Koschinsky, Andrea; Mikesell, Mariah; Mizell, Kira; Glenn, Craig R.; Wood, Ray

    2016-01-01

    Marine phosphorites are known to concentrate rare earth elements and yttrium (REY) during early diagenetic formation. Much of the REY data available are decades old and incomplete, and there has not been a systematic study of REY distributions in marine phosphorite deposits that formed over a range of oceanic environments. Consequently, we initiated this study to determine if marine phosphorite deposits found in the global ocean host REY concentrations of high enough grade to be of economic interest. This paper addresses continental-margin (CM) and open-ocean seamount phosphorites. All 75 samples analyzed are composed predominantly of carbonate fluorapatite and minor detrital and authigenic minerals. CM phosphorites have low total REY contents (mean 161 ppm) and high heavy REY (HREY) complements (mean 49%), while seamount phosphorites have 4–6 times higher individual REY contents (except for Ce, which is subequal; mean ΣREY 727 ppm), and very high HREY complements (mean 60%). The predominant causes of higher concentrations and larger HREY complements in seamount phosphorites compared to CM phosphorites are age, changes in seawater REY concentrations over time, water depth of formation, changes in pH and complexing ligands, and differences in organic carbon content in the depositional environments. Potential ore deposits with high HREY complements, like the marine phosphorites analyzed here, could help supply the HREY needed for high-tech and green-tech applications without creating an oversupply of the LREY.

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

    PubMed

    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.

  14. Mineralogy and geochemistry of the Neo-Tethyan Orhaneli ultramafic suite, NW Turkey: Evidence for the initiation and evolution of magmatic processes in a developing crust-mantle boundary

    NASA Astrophysics Data System (ADS)

    Uysal, Ibrahim; Dokuz, Abdurrahman; Kapsiotis, Argyris; Kaliwoda, Melanie; Karsli, Orhan; Müller, Dirk; Aydin, Faruk

    2017-04-01

    The eastern Orhaneli ophiolitic massif, located in NW Anatolia, Turkey, forms part of the northwestern branch of the so-called Neotethys Ocean across the Izmir-Ankara-Erzincan Suture Zone. It is comprised mainly of a well preserved ultramafic suite, dominated by voluminous dunite exposures, accompanied by subsidiary harzburgite occurrences. The entire suite is commonly cross cut by a complex network of relatively undeformed clinopyroxenite veins. Clinopyroxene and spinel compositions in harzburgites are moderately depleted, whereas their whole-rock heavy rare earth element (HREE) abundances are consistent with harzburgite formation after approximately 19% dry melting of a spinel-bearing fertile mantle protolith at an extentional geotectonic regime. Nevertheless, textural data indicate that protracted dissolution of pyroxene coupled with precipitation of olivine happened during the transformation of harzburgites to replacive dunites, containing olivine with high Fo [Fo = 100×Mg/(Mg + Fe2+)] content (91.3-94.2) and spinel with elevated Cr# [100×Cr/(Cr + Al)] values (78-82). Such highly depleted mineralogical signatures imply that dunite for harzburgite substitution occurred under hydrous melting conditions in the mantle region above a subducted oceanic slab. Enrichments in incompatible elements (e.g., Cs, Rb and Sr) and the characteristic U-shaped chondrite-normalized rare earth elements (REE) profiles exhibited by replacive dunites along with the elevated TiO2 (0.20-0.36 wt.%) contents in their accessory spinels indicate that the reactive melt had an intermediate affinity between boninite and island arc tholeiite (IAT) regimes. The metasomatic reaction triggered an additional 8% melting of the harzburgite residue. The resultant melt fractionated (,almost in situ,) to crystallize cumulate dunites composed of olivine with relatively high Fo content (88.8-92.3), spinel with moderate Cr# values (62-74), as well as clinopyroxene with a depleted composition (low TiO2 and Al2O3 contents and high Mg#) identical of clinopyroxene in arc-derived peridotites. These magmatically formed dunites are rich in light rare earth elements (LREE) and commonly carry elevated Pt+Pd concentrations (up to 17.92 ppb), especially compared to replacive dunites that are almost deprived of Pt and Pd (up to 3.92 ppb). Further upward movement and differentiation of this melt caused the formation of clinopyroxenites, containing spinel similar in composition to that of cumulate dunites, with elevated Pt+Pd abundances (up to 499.75 ppb) and LREE-depleted multi-element patterns typical of crystallization from a melt with comparable composition between boninite and IAT. Overall data indicate that the studied ultramafic suite represents part of a sub-oceanic Moho transition zone, which preserves mixed mantle and cumulate characteristics.

  15. Thermochemistry of rare earth doped uranium oxides LnxU1-xO2-0.5x+y (Ln = La, Y, Nd)

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Navrotsky, Alexandra

    2015-10-01

    Lanthanum, yttrium, and neodymium doped uranium dioxide samples in the fluorite structure have been synthesized, characterized in terms of metal ratio and oxygen content, and their enthalpies of formation measured by high temperature oxide melt solution calorimetry. For oxides doped with 10-50 mol % rare earth (Ln) cations, the formation enthalpies from constituent oxides (LnO1.5, UO2 and UO3 in a reaction not involving oxidation or reduction) become increasingly exothermic with increasing rare earth content, while showing no significant dependence on the varying uranium oxidation state. The oxidation enthalpy of LnxU1-xO2-0.5x+y is similar to that of UO2 to UO3 for all three rare earth doped systems. Though this may suggest that the oxidized uranium in these systems is energetically similar to that in the hexavalent state, thermochemical data alone can not constrain whether the uranium is present as U5+, U6+, or a mixture of oxidation states. The formation enthalpies from elements calculated from the calorimetric data are generally consistent with those from free energy measurements.

  16. Major and trace element, and Sr isotope compositions of clinopyroxene phenocrysts in mafic dykes on Jiaodong Peninsula, southeastern North China Craton: Insights into magma mixing and source metasomatism

    NASA Astrophysics Data System (ADS)

    Liang, Yayun; Deng, Jun; Liu, Xuefei; Wang, Qingfei; Qin, Cheng; Li, Yan; Yang, Yi; Zhou, Mian; Jiang, Jieyan

    2018-03-01

    Early Cretaceous mafic dyke swarms are widely developed on Jiaodong Peninsula in the southeastern part of the North China Craton (NCC), but their petrogenesis remains enigmatic. We have examined the in-situ major element, trace element and Sr isotope compositions of the clinopyroxene phenocrysts in these dykes in order to evaluate the extent of magma mixing and source metasomatism. Depending on the type of mineral zoning, the clinopyroxene phenocrysts in our samples can be classified into two groups: Group I (reverse zoning) and Group II (no zoning). Based on core compositions, the Group I phenocrysts with obvious reverse zoning can be divided into two subgroups: Groups IA and IB. The cores of Group IA clinopyroxenes have low values of Mg#, low Al2O3 contents, high Na2O contents, and high 87Sr/86Sr ratios, and they were probably derived from newly accreted lower crust that formed through the underplating of basaltic magma. In contrast, the cores of Group IB clinopyroxenes have lower Mg# values and lower contents of Al2O3, ΣREE (total rare earth elements), and incompatible elements, but they have similar 87Sr/86Sr ratios; these cores crystallised from crust-derived andesitic-dacitic magma. Group IA and IB clinopyroxene phenocryst rims (Group I rims) all have similar compositions with higher values of Mg# and higher Al2O3, Cr and Ni contents than the cores. The rims have high 87Sr/86Sr ratios, are enriched in LREEs (light rare earth elements) and LILEs (large ion lithophile elements), and are depleted in HFSEs (high field strength elements); these characteristics indicate that all the high-Mg rims were derived from a similar magma, possibly a relatively primitive magma derived from lithospheric mantle. We suggest, therefore, that the reversely-zoned clinopyroxene phenocrysts (Group I) in the Jiaodong mafic dykes provide evidence of magma mixing between a magma derived from lithospheric mantle and crust-derived andesitic-dacitic melt alongside with the newly accreted lower crust. The Group II clinopyroxene phenocrysts, which lack zoning, display major and trace element compositions and 87Sr/86Sr ratios that are similar to those of the Group I rims, which indicates that all the high-Mg clinopyroxenes were derived from a common source in the lithospheric mantle. These high-Mg clinopyroxenes exhibit high 87Sr/86Sr ratios, high Sr contents and remarkable depletions in HFSEs, reflecting metasomatism of the mantle source by aqueous fluids derived by dehydration of the subducting slab and its marine sediments. The metasomatism of the source reveals that the lithospheric mantle beneath Jiaodong Peninsula was metasomatised by fluids from the subducting Paleo-Pacific slab. Progressive thinning of the lithosphere mantle under the NCC was induced by continuous thermo-mechanical erosion, promoting the partial melting of lithospheric mantle and generating the mafic dykes at Jiaodong. Table A2 Analytical results for the trace element standards used during LA-ICP-MS analyses of clinopyroxene phenocrysts. Table A3 Analytical results for the Sr isotope standards used during MC-ICP-MS analyses of clinopyroxene phenocrysts. Table A4 Major element contents (wt%) of clinopyroxene phenocrysts from the mafic dykes on Jiaodong Peninsula. Table A5 Representative Sr isotopic compositions of clinopyroxene phenocrysts from the mafic dykes on Jiaodong Peninsula. Table A6 Geochemistry of the mafic dykes on Jiaodong Peninsula. Table A7 Partition coefficients (KD) and end-member components used for REE modeling.

  17. Publications - GMC 370 | Alaska Division of Geological & Geophysical

    Science.gov Websites

    (249.0 K) Keywords Rare Earth Elements Top of Page Department of Natural Resources, Division of Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

  18. Identification of species of the Euterpe genus by rare earth elements using inductively coupled plasma mass spectrometry and linear discriminant analysis.

    PubMed

    Santos, Vívian Silva; Nardini, Viviani; Cunha, Luís Carlos; Barbosa, Fernando; De Almeida Teixeira, Gustavo Henrique

    2014-06-15

    The açaí (Euterpe oleracea Mart.) and juçara (Euterpe edulis Mart.) produce similar fruits which are rich in energy, minerals, vitamins and natural compounds with antioxidant and anti-inflammatory properties. Although the drink obtained from these species is similar, it is important to develop tools to establish the identity of the fruit species and growing regions. To assess claims of origin and for other purposes, we use multivariate analysis to investigate the differentiation of açaí and juçara fruits based on rare earth element (REE) content determined by Inductively Coupled Plasma Mass Spectrometry. REE content, in particular Sm, Th, La, Pr, Gd, and especially Ce and Nd varied between species. PCA analysis was not efficient in differentiating açaí from juçara fruit samples. In contrast, LDA analysis permitted a correct differentiation between species with a predictive ability of 83.3%. The methodology that we have applied confirms that REE can be used to differentiate between açaí and juçara fruit samples and to identify their origin. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. The Ins and Outs of Water in the Earth's Mantle

    NASA Astrophysics Data System (ADS)

    Hauri, E. H.; Gaetani, G. A.; Shaw, A. M.; Kelley, K. A.; Saal, A. E.

    2005-12-01

    Most of the hydrogen in the Earth's upper mantle is dissolved in nominally anhydrous minerals such as olivine, orthopyroxene, clinopyroxene and garnet as structural OH [e.g. 1 ]. Considering the significant influence of hydrogen on mantle properties such as solidus temperature, rheology, conductivity and seismic velocity, it is important to understand both the distribution of water among mantle phases and the mass transfer processes that influence water distribution in the Earth's mantle. Despite the important role of water in the mantle, experimental determinations of the equilibrium distribution of trace amounts of hydrogen among coexisting silicate phases remain extremely limited. Improved analytical techniques have recently paved the way for quantitative investigations of water partitioning and abundances in nominally anhydrous mantle minerals [e.g. 2]. Several studies of submarine glasses have revealed correlated increases in incompatible elements and water contents along segments of mid-ocean ridges approaching hotspots [e.g. 3,4]. A source-related increase in the water content of the mantle is typically postulated to explain such observations, but elevated hotspot H2O contents may also relate to pressure differences in partitioning of water, analogous to the case for rare-earth elements (e.g. the "garnet signature"). New experimental water partitioning data illuminate these differences. Hydrogen isotope ratios vary in submarine glasses from ocean ridges, back-arc basins and hotspots, and in hydrous phases from arcs and hotspots, suggesting significant hydrogen isotopic variability in the mantle, which may be related to the subduction of water. Water clearly enters the upper mantle at subduction zones, however the full water budget for any single subduction zone is highly uncertain [e.g. 5]. This uncertainty in the water budget at convergent margins indicates that we do not even know whether the present-day net flux of water is into or out of the Earth. This talk will highlight areas of both knowledge and ignorance on the origin and distribution of water in the Earth's mantle. [1] Bell, D.R. & Rossman, G.R., 1992, Science, 255: 1391-1397. [2] Koga, K. et. al, 2002, Geochem. Geophys. Geosys. 4, doi: 10.1029/2002GC000378. [3] Dixon, J. E. et. al, 2002, Nature 420, 385-389. [4] Asimow, P. D. et. al, 2003, Geochem. Geophys. Geosys. 5, doi:10.1029/2003GC000568. [5] Hilton D. R.. et. al, 2002, in Noble Gases in Cosmochemistry and Geochemistry, 47:319-370.

  20. Chemistry and origin of minor and trace elements in vitrinite concentrates from a rank series from the eastern United States, England, and Australia

    USGS Publications Warehouse

    Lyons, P.C.; Palmer, C.A.; Bostick, N.H.; Fletcher, J.D.; Dulong, F.T.; Brown, F.W.; Brown, Z.A.; Krasnow, M.R.; Romankiw, L.A.

    1989-01-01

    A rank series consisting of twelve vitrinite concentrates and companion whole-coal samples from mined coal beds in the eastern United States, England, and Australia were analyzed for C, H, N, O, ash, and 47 trace and minor elements by standard elemental, instrumental neutron activation analysis (INAA), and direct-current-arc spectrographic (DCAS) techniques. The reflectance of vitrinite, atomic H:C and O:C, and ash-free carbon data were used to determine ranks that range from high-volatile C bituminous coal to meta-anthracite. A van Krevelen (atomic H:C vs. O:C) diagram of the vitrinite concentrates shows a smooth curve having its lowest point at H:C = 0.18 and O:C = 0.01. This improves the van Krevelen diagram by the addition of our vitrinite concentrate from meta-anthracite from the Narragansett basin of New England. Boron content (400-450 ppm) in two Illinois basin vitrinite concentrates was about an order of magnitude higher than B contents in other concentrates analyzed. We attribute this to marine origin or hydrothermal activity. The alkaline-earth elements Ca, Mg and Ba (DCAS) have higher concentrations in our vitrinite concentrates from bituminous coals of the Appalachian basin, than they do in vitrinite concentrates from the marine-roofed bituminous coals of the Illinois basin; therefore, a nonmarine origin for these alkaline-earth elements is postulated for the Appalachian basin coals. An ion-exchange mechanism due to high concentrations of these elements as ions in diagenetic water, but probably not recent ground water, may be responsible for the relatively high values of these elements in Appalachian concentrates. Higher concentrations of Ni and Cr in one of the English vitrinite concentrates and of Zr in the Australian concentrate probably indicate organic association and detrital influence, respectively. ?? 1989.

  1. Early evolution of the Earth: Accretion, atmosphere formation, and thermal history

    NASA Astrophysics Data System (ADS)

    Abe, Yutaka; Matsui, Takafumi

    1986-03-01

    Atmospheric and thermal evolution of the earth growing by planetesimal impacts was modeled by taking into account the blanketing effect of an impact-induced H2O atmosphere and the temperature dependence of H2O degassing. When the water content of planetesimals is larger than 0.1% by weight and the accretion time of the earth is less than 5 × 107 years, the surface of the accreting earth melts and thus a “magma ocean” forms and covers the surface. The formation of a “magma ocean” will result in the initiation of core-mantle separation and mantle differentiation during accretion. Once a magma ocean is formed, the surface temperature, the degree of melting in the magma ocean, and the mass of the H2O atmosphere are nearly constant as the protoplanet grows further. The final mass of the H2O atmosphere is about 1021 kg, a value which is insensitive to variations in the model parameter values such as the accretion time and the water content of planetesimals. That the final mass of the H2O atmosphere is close to the mass of the present oceans suggests an impact origin for the earth's hydrosphere. On the other hand, most of the H2O retained in planetesimals will be deposited in the solid earth. Free water within the proto-earth may affect differentiation of the proto-mantle, in particular, the mantle FeO abundance and the incorporation of a light element in the outer core.

  2. Quantification of rare earth elements using laser-induced breakdown spectroscopy

    DOE PAGES

    Martin, Madhavi; Martin, Rodger C.; Allman, Steve; ...

    2015-10-21

    In this paper, a study of the optical emission as a function of concentration of laser-ablated yttrium (Y) and of six rare earth elements, europium (Eu), gadolinium (Gd), lanthanum (La), praseodymium (Pr), neodymium (Nd), and samarium (Sm), has been evaluated using the laser-induced breakdown spectroscopy (LIBS) technique. Statistical methodology using multivariate analysis has been used to obtain the sampling errors, coefficient of regression, calibration, and cross-validation of measurements as they relate to the LIBS analysis in graphite-matrix pellets that were doped with elements at several concentrations. Each element (in oxide form) was mixed in the graphite matrix in percentages rangingmore » from 1% to 50% by weight and the LIBS spectra obtained for each composition as well as for pure oxide samples. Finally, a single pellet was mixed with all the elements in equal oxide masses to determine if we can identify the elemental peaks in a mixed pellet. This dataset is relevant for future application to studies of fission product content and distribution in irradiated nuclear fuels. These results demonstrate that LIBS technique is inherently well suited for the future challenge of in situ analysis of nuclear materials. Finally, these studies also show that LIBS spectral analysis using statistical methodology can provide quantitative results and suggest an approach in future to the far more challenging multielemental analysis of ~ 20 primary elements in high-burnup nuclear reactor fuel.« less

  3. Black carbon, mass and elemental measurements of airborne particles in the village of Serowe, Botswana

    NASA Astrophysics Data System (ADS)

    Moloi, K.; Chimidza, S.; Lindgren, E. Selin; Viksna, A.; Standzenieks, P.

    Absorption of sunlight by sub-micron particles is an important factor in calculations of the radiation balance of the earth and thus in climate modelling. Carbon-containing particles are generally considered as the most important in this respect. Major sources of these particles are generally considered to be bio-mass burning and vehicle exhaust. In order to characterise size fractionated particulate matter in a rural village in Botswana with respect to light absorption and elemental content experiments were performed, in which simultaneous sampling was made with a dichotomous impactor and a laboratory-made sampler, made compatible with black carbon analysis by reflectometry. The dichotomous impactor was equipped with Teflon filters and the other sampler with glass fibre filters. Energy dispersive X-ray fluorescence was used for elemental analysis of both kinds of filters. It appeared that Teflon filters were the most suitable for the combination of mass-, elemental- and black carbon measurements. The black carbon content in coarse (2.5-10 μm) and fine (<2.5 μm) particles was determined separately and related to elemental content and emission source. The results show that the fine particle fraction in the aerosol has a much higher contribution of black particles than the coarse particle fraction. This observation is valid for the village in Botswana as well as for a typical industrialised city in Sweden, used as a reference location.

  4. Paleoenvironmental signals and paleoclimatic condition of the Early Maastrichtian oil shales from Central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Fathy, Douaa; Wagreich, Michael; Zaki, Rafat; Mohamed, Ramadan S. A.

    2016-04-01

    Early Maastrichtian oil shales are hosted in the Duwi Formation of the Central Eastern Desert, Egypt. The examined member represents up to 20% of the total Duwi Formation. This interval is mainly composed of siliciclastic facies, phosphorites facies and carbonate facies. Oil shales microfacies is mainly composed of smectite, kaolinite, calcite, fluorapatite, quartz and pyrite. They are enriched in a number of major elements and trace metals in particular Ca, P, V, Ni, Cr, Sr, Zn, Mo, Nb, U and Y compared to the post-Archaean Australian shale (PAAS). Chondrite-normalized REEs patterns of oil shales for the studied area display light rare earth elements enrichment relatively to heavy rare earth elements with negative Ce/Ce* and Eu/Eu* anomalies. The most remarkable indicators for redox conditions are enrichments of V, Mo, Ni, Cr, U content and depletion of Mn content. Besides, V/V+Ni, V/Ni, U/Th, Ni/Co, authigentic uranium ratios with presence of framboidal shape of pyrite and its size are reflecting the deposition of these shales under marine anoxic to euxinic environmental conditions. Additionally, the ratio of Strontium (Sr) to Barium (Ba) Sr/Ba reflected highly saline water during deposition. Elemental ratios critical to paleoclimate and paleoweathering (Rb /Sr, Al2O3/TiO2), CIA values, binary diagram between (Al2O3+K2O+Na2O) and SiO2 and types of clay minerals dominated reflect warm to humid climate conditions prevailing during the accumulation of these organic-rich petroleum source rocks.

  5. [Differential study of the bonding characterization of dental porcelain to Ni-Cr alloys].

    PubMed

    Wei, Fang; Zhan, De-song; Wang, Yan-yan

    2008-10-01

    To study the bonding capability when Ni-Cr porcelain alloy was added with Ti, compound rare earth metals and removed the element of Be. Ni-Cr-Ti porcelain alloys manufactured by Institute of Metal Research of Chinese Academy of Sciences were tested. The test alloys were divided into three groups according to whether containing Be and compound rare earth metals or not. And HI BOND Ni-Cr base-metal alloy was chosen as control. The metal-ceramic specimens were prepared for shear test, scanning electron microscope (SEM) and energy spectrum analysis. The shear bond strength of the four groups were analyzed. No significant difference were observed among them (P > 0.05). No crackle was found and they were contacted tightly between the porcelain and metal. The composition and contents of the four groups' interfaces were closed. The shear bond strength of the self-made Ni-Cr-Ti porcelain alloys all can satisfy the clinical requirements. Experimental groups containing Ti, compound rare earth metals and removing the element of Be can be used as better recommendation for clinical practice.

  6. Separation of thorium (IV) from lanthanide concentrate (LC) and water leach purification (WLP) residue

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman

    Thorium (IV) content in industrial residue produced from rare earth elements production industry is one of the challenges to Malaysian environment. Separation of thorium from the lanthanide concentrate (LC) and Water Leach Purification (WLP) residue from rare earth elements production plant is described. Both materials have been tested by sulphuric acid and alkaline digestions. Th concentrations in LC and WLP were determined to be 1289.7 ± 129 and 1952.9±17.6 ppm respectively. The results of separation show that the recovery of Th separation from rare earth in LC after concentrated sulphuric acid dissolution and reduction of acidity to precipitate Th wasmore » found 1.76-1.20% whereas Th recovery from WLP was less than 4% after concentrated acids and alkali digestion processes. Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) was used to determine Th concentrations in aqueous phase during separation stages. This study indicated that thorium maybe exists in refractory and insoluble form which is difficult to separate by these processes and stays in WLP residue as naturally occurring radioactive material (NORM)« less

  7. Rare earth and trace element geochemistry of a fragment of Jurassic seafloor, Point Sal, California

    NASA Technical Reports Server (NTRS)

    Menzies, M.; Blanchard, D.; Brannon, J.; Korotev, R.

    1977-01-01

    Rocks from an ophiolite suite once on the seafloor were analyzed for rare earth elements (REE), Sc, Co, Na2O, Cr, Zn and FeO. Strontium isotope exchange noted in some of the lavas is attributed to basalt-seawater interaction; the Ce abundance in smectite- and zeolite-bearing lavas may also be due to prolonged exposure to seawater. The higher grades of metamorphic rock, however, show no variation from the usual flat or slightly light REE depleted profiles. Plutonic igneous rock, all light REE depleted, have total REE abundances varying by a factor of 100 between the dunites and diorites. In order of decreasing REE abundance are hornblende, clinopyroxene, plagioclase, orthopyroxene and olivine. Calculations of REE contents of liquids in equilibrium with early cumulative clinopyroxenes suggest that the parent to the stratiform sequence was more depleted in light REE than the parent to the lava pile.

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  9. Rare earth elements geochemistry in springs from Taftan geothermal area SE Iran

    NASA Astrophysics Data System (ADS)

    Shakeri, Ata; Ghoreyshinia, Sayedkazem; Mehrabi, Behzad; Delavari, Morteza

    2015-10-01

    Concentrations of rare earth elements (REEs) were determined in springs and andesitic-dacitic rocks of Taftan geothermal field. Hydrochemical results of major ions indicate that thermal springs are Na-SO4-Cl and Ca-SO4-Cl types. Concentrations of REEs are in ranges of 10- 4 to 1.2 and 49 to 62 times of chondrite for springwater and rock samples, respectively. The thermal (STS and TTS) and the cold (APS) springs with low pH values exhibit a very high REE contents (0.64 to 3.15 mg/l). Saturation index indicates that Fe and Al phases can control dissolved REE concentration in FTS and PF cold springs. The speciation of REE complexes indicates dominant presence of LnSO4+ and free ion in the Taftan thermal springs. In APS cold spring with pH 4, fluoride complexes are dominate over the free ion and sulfate species, while in PF and FTS cold springs with pH 6.4 and 7, respectively, carbonate complexes (LnCO3+) are predominant species. Chondrite-normalized pattern for the low-pH waters show very distinctive gull-wing patterns, characteristic feature of acid-sulfate geothermal systems, and are similar to those of the host rocks. Chemical characteristics of rare earth elements in spring and volcanic rock samples indicate that REEs are originated from the andesitic-dacitic host rocks. Whole-rock-normalized REE patterns and petrographic evidences show that rare earth elements leached mainly from marginal alteration of minerals and matrix decomposition in volcanic rocks. In chondrite-normalized REE patterns, significant negative Eu anomaly in the cold springs compare to the thermal and acidic springs indicates that alteration of plagioclase is more intense in the later, corresponding to increasing in temperature and acidic state of reactant water.

  10. A Novel Synthesis Routine for Woodwardite and Its Affinity towards Light (La, Ce, Nd) and Heavy (Gd and Y) Rare Earth Elements.

    PubMed

    Consani, Sirio; Balić-Žunić, Tonci; Cardinale, Anna Maria; Sgroi, Walter; Giuli, Gabriele; Carbone, Cristina

    2018-01-14

    A synthetic Cu-Al-SO₄ layered double hydroxide (LDH), analogue to the mineral woodwardite [Cu 1-x Al x (SO₄) x/2 (OH)₂·nH₂O], with x < 0.5 and n ≤ 3x/2, was synthesised by adding a solution of Cu and Al sulphates to a solution with NaOH. The pH values were kept constant at 8.0 and 10.0 by a continuous addition of NaOH. The material obtained had poor crystallinity, turbostratic structure, and consisted of nanoscopic crystallites. The analyses performed in order to characterise the obtained materials (X-ray diffraction (XRD), thermogravimetry (TG), and Fourier Transform Infra-Red (FTIR) spectroscopy) showed that the Cu-Al-SO₄ LDH is very similar to woodwardite, although it has a smaller layer spacing, presumably due to a lesser water content than in natural samples. The synthesis was performed by adding light rare earth elements (LREEs) (La, Ce, and Nd) and heavy rare earth elements (HREEs) (Gd and Y) in order to test the affinity of the Cu-Al-SO₄ LDH to the incorporation of REEs. The concentration of rare earth elements (REEs) in the solid fraction was in the range of 3.5-8 wt %. The results showed a good affinity for HREE and Nd, especially for materials synthesised at pH 10.0, whereas the affinities for Ce and La were much lower or non-existent. The thermal decomposition of the REE-doped materials generates a mixture of Cu, Al, and REE oxides, making them interesting as precursors in REE oxide synthesis.

  11. A Novel Synthesis Routine for Woodwardite and Its Affinity towards Light (La, Ce, Nd) and Heavy (Gd and Y) Rare Earth Elements

    PubMed Central

    Consani, Sirio; Balić-Žunić, Tonci; Cardinale, Anna Maria; Sgroi, Walter; Giuli, Gabriele; Carbone, Cristina

    2018-01-01

    A synthetic Cu-Al-SO4 layered double hydroxide (LDH), analogue to the mineral woodwardite [Cu1−xAlx(SO4)x/2(OH)2·nH2O], with x < 0.5 and n ≤ 3x/2, was synthesised by adding a solution of Cu and Al sulphates to a solution with NaOH. The pH values were kept constant at 8.0 and 10.0 by a continuous addition of NaOH. The material obtained had poor crystallinity, turbostratic structure, and consisted of nanoscopic crystallites. The analyses performed in order to characterise the obtained materials (X-ray diffraction (XRD), thermogravimetry (TG), and Fourier Transform Infra-Red (FTIR) spectroscopy) showed that the Cu-Al-SO4 LDH is very similar to woodwardite, although it has a smaller layer spacing, presumably due to a lesser water content than in natural samples. The synthesis was performed by adding light rare earth elements (LREEs) (La, Ce, and Nd) and heavy rare earth elements (HREEs) (Gd and Y) in order to test the affinity of the Cu-Al-SO4 LDH to the incorporation of REEs. The concentration of rare earth elements (REEs) in the solid fraction was in the range of 3.5–8 wt %. The results showed a good affinity for HREE and Nd, especially for materials synthesised at pH 10.0, whereas the affinities for Ce and La were much lower or non-existent. The thermal decomposition of the REE-doped materials generates a mixture of Cu, Al, and REE oxides, making them interesting as precursors in REE oxide synthesis. PMID:29342887

  12. Analysis of the combined effects of lanthanum and acid rain, and their mechanisms, on nitrate reductase transcription in plants.

    PubMed

    Xia, Binxin; Sun, Zhaoguo; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2017-04-01

    Rare earth element (REE) pollution and acid rain are major global environmental concerns, and their spatial distributions overlap. Thus, both forms of pollution combine to act on plants. Nitrogen is important for plant growth, and nitrate reductase (NR) is a key plant enzyme that catalyzes nitrogen assimilation. Studying the combined effects of REEs and acid rain on plant nitrogen-based nutrients has important environmental significance. Here, soybean (Glycine max) plants, commonly used for toxicological studies, were exposed to lanthanum (La), a REE, and acid rain to study the NR activities and NR transcriptional levels in the roots. To explain how the pollution affected the NR transcriptional level, we simultaneously observed the contents of intracellular La and nutrient elements, protoplast morphology, membrane lipid peroxidation and intracellular pH. A combined treatment of 0.08mmol/L La and pH 4.5 acid rain increased the NR activity, decreased the NR transcriptional level, increased the intracellular nutrient elements' contents and caused deformations in membrane structures. Other combined treatments significantly decreased the aforementioned parameters and caused serious damage to the membrane structures. The variation in the amplitudes of combined treatments was greater than those of individual treatments. Compared with the control and individual treatments, combined treatments increased membrane permeability, the malondialdehyde content, and intracellular H + and La contents, and with an increasing La concentration or acid strength, the change in amplitude increased. Thus, the combined effects on NR gene transcription in soybean seedling roots were related to the intracellular nutrient elements' contents, protoplast morphology, membranous lipid peroxidation, intracellular pH and La content. Copyright © 2016 Elsevier Inc. All rights reserved.

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

    USGS Publications Warehouse

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

    2011-01-01

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

  14. Profiling elements in Puerh tea from Yunnan province, China.

    PubMed

    Zhang, Jianyang; Ma, Guicen; Chen, Liyan; Liu, Ting; Liu, Xin; Lu, Chengyin

    2017-09-01

    Puerh tea, as the most representative Chinese dark tea, has attracted global interest in recent years. Profiling the levels of metal elements in Puerh tea is very important since its presence is related to human health. In this study, 41 elements in 98 Puerh tea samples from Yunnan province, China including Puerh raw tea and Puerh ripe tea were evaluated by microwave digestion combined with inductively coupled plasma mass spectrometry . The content of toxic elements, essential elements and rare earth elements of Puerh tea from different regions was discussed in detail. The concentrations of Ba, Cr, As, Pb, Bi, Fe, Zn, V, Mn, Be, Ag and Tl showed significant differences (p < 0.05) by ANOVA analysis. Principal component analysis and linear discriminant analysis were used to describe the relationship of Puerh tea from different regions. This study provided a comprehensive database for Puerh tea quality control and intake risk assessment.

  15. Heterogeneity in mantle carbon content from CO2-undersaturated basalts

    PubMed Central

    Le Voyer, M.; Kelley, K.A.; Cottrell, E.; Hauri, E.H.

    2017-01-01

    The amount of carbon present in Earth's mantle affects the dynamics of melting, volcanic eruption style and the evolution of Earth's atmosphere via planetary outgassing. Mantle carbon concentrations are difficult to quantify because most magmas are strongly degassed upon eruption. Here we report undegassed carbon concentrations from a new set of olivine-hosted melt inclusions from the Mid-Atlantic Ridge. We use the correlations of CO2 with trace elements to define an average carbon abundance for the upper mantle. Our results indicate that the upper mantle carbon content is highly heterogeneous, varying by almost two orders of magnitude globally, with the potential to produce large geographic variations in melt fraction below the volatile-free solidus. Such heterogeneity will manifest as variations in the depths at which melt becomes interconnected and detectable, the CO2 fluxes at mid-ocean ridges, the depth of the lithosphere-asthenosphere boundary, and mantle conductivity. PMID:28082738

  16. Seventh Annual V. M. Goldschmidt Conference

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Topics considered include: Subduction of the Aseismic Cocos Ridge Displaced Magma Sources Beneath the Cordillera de Talamanca, Costa Rica; Topography of Transition Zone Discontinuities: A Measure of 'Olivine' Content and Evidence for Deep Cratonic Roots; Uranium Enrichment in Lithospheric Mantle: Case Studies from French Massif Central; Rare-Earth-Element Anomalies in the Decollement Zone of the nankai Accretionary Prism, Japan: Evidence of Fluid Flow?; Rare Earth Elements in Japanese Mudrocks: The Influence of Provenance; The Evolution of Seawater Strontium Isotopes in the Last Hundred Million Years: Reinterpretation and Consequences for Erosion and Climate Models; From Pat to Tats: The Lead Isotope Legacy in the Studies of the Continental Crust-Upper Mantle System; Geochronology of the Jack Hills Detrital Zircons by Precise Uranium-Lead Isotope-Dilution Analysis of Crystal Fragments; Iridium in the Oceans; The Helium-Heat-Lead Paradox; Control of Distribution Patterns of Heavy Metals in Ganga Plain Around Kanpur Region, India, by Fluvial Geomorphic Domains; Geochemical and Isotopic Features of Ferrar Magmatic Provience (Victoria Land, Antarctica); Rare Earth Elements in Marine Fine-Grained Sediments from the Northwestern Portuguese Shelf (Atlantic); Aspects of Arc Fluxes; General Kinetic Model for Dolomite Precipitation Rate with Application to the Secular History of Seawater Composition; High-Precision Uranium-series Chronology from Speleothems; Trace-Element Modeling of Aqueous Fluid-Peridotite Interaction in the Mantle Wedge of Subduction Zones; Rainfall Variations in Southeastern Australia over the Last 500,000 Years from Speleothem Deposition; The Role of Water in High-Pressure Fluids; The Kinetic Conditions of Metamorphic Minearogenesis: Evidence from Minerals and Assemblages.

  17. [Distribution Characteristics and Source Analysis of Dustfall Trace Elements During Winter in Beijing].

    PubMed

    Xiong, Qiu-lin; Zhao, Wen-ji; Guo, Xiao-yu; Chen, Fan-tao; Shu, Tong-tong; Zheng, Xiao-xia; Zhao, Wen-hui

    2015-08-01

    The dustfall content is one of the evaluation indexes of atmospheric pollution. Trace elements especially heavy metals in dustfall can lead to risks to ecological environment and human health. In order to study the distribution characteristics of trace elements, heavy metals pollution and their sources in winter atmospheric dust, 49 dustfall samples were collected in Beijing City and nearby during November 2013 to March 2014. Then the contents (mass percentages) of 40 trace elements were measured by Elan DRC It type inductively coupled plasma mass (ICP-MS). Test results showed that more than half of the trace elements in the dust were less than 10 mg x kg(-1); about a quarter were between 10-100 mg x kg-1); while 7 elements (Pb, Zr, Cr, Cu, Zn, Sr and Ba) were more than 100 mg x kg(-1). The contents of Pb, Cu, Zn, Bi, Cd and Mo of winter dustfall in Beijing city.were respectively 4.18, 4.66, 5.35, 6.31, 6.62, and 8.62 times as high as those of corresponding elements in the surface soil in the same period, which went beyond the soil background values by more than 300% . The contribution of human activities to dustfall trace heavy metals content in Beijing city was larger than that in the surrounding region. Then sources analysis of dustfall and its 20 main trace elements (Cd, Mo, Nb, Ga, Co, Y, Nd, Li, La, Ni, Rb, V, Ce, Pb, Zr, Cr, Cu, Zn, Sr, Ba) was conducted through a multi-method analysis, including Pearson correlation analysis, Kendall correlation coefficient analysis and principal component analysis. Research results indicated that sources of winter dustfall in Beijing city were mainly composed of the earth's crust sources (including road dust, construction dust and remote transmission of dust) and the burning of fossil fuels (vehicle emissions, coal combustion, biomass combustion and industrial processes).

  18. Uranium, yttrium, and rare earth elements accumulation during the Cretaceous anoxic events in carbonaceous rocks in the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Savelyeva, Olga; Philosofova, Tatyana; Bergal-Kuvikas, Olga; Savelyeva, Svetlana

    2017-04-01

    We have studied the carbonate-siliceous section of paleooceanic Albian-Cenomanian deposits on the Kamchatsky Mys peninsula (Eastern Kamchatka, Russia) [1].The section is represented by a rhythmic alternation of planktonic limestones and jaspers, accumulated in the open ocean environment. The rhythmicity can be attributed to climate variations that reflect a fluctuation of astronomical parameters (Milankovitch cycles) [2, 3].The section contains two beds enriched in organic carbon, corresponding to the two oceanic anoxic events - MCE and OAE2 [3]. The maximum content of organic matter in those beds reaches 68%. Our geochemical studies revealed an enrichment of the carbonaceous rocks in some major and trace elements including PGE, in comparison with the surrounding limestone and jasper [4].The accumulation of the ore elements in carbonaceous beds is caused by euxinic conditions during sedimentation.The content of uranium, yttrium, and rare earth elements in carbonaceous rocks is up to 60, 142 and 312 ppm respectively. Phosphate grains (bone detritus) with microinclusions of yttrium and uranium minerals were revealed in the carbonaceous rocks using the scanning electron microscope. These data prove the hypothesis of the sorbtion of U and Y by phosphate detritus from seawater. Microprobe analysis also showed an increased content of Cu, Zn, V in some pyrite framboids, which indicates that these elements are fixed in rocks by Fe-sulphide phase or organic matter under euxinic conditions. Our research may bring us closer to understanding the mechanism of syngenetic accumulation of metals in the black shales. This work was supported by the RFBR (No. 16-05-00546). [1] Palechek, T.N., Savelyev, D.P., Savelyeva, O.L. (2010) Stratigraphy and Geological Correlation 18, (1) 63-82. [2] Savelyeva, O.L. (2010). Vestnik Kraunts. Nauki o zemle 1 (15), 45-55 (in Russian). [3] Savelyev, D.P., Savelyeva, O.L., Palechek, T.N., Pokrovsky, B.G. (2012) Geophysical Research Abstracts, 14, EGU2012-1940. [4] Savelyeva, O., Palesskiy, S., Savelyev, D. (2015) Goldschmidt Abstracts, 2015. 2779.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Blanchard, I.; Badro, J.; Siebert, J.

    We present gallium concentration (normalized to CI chondrites) in the mantle is at the same level as that of lithophile elements with similar volatility, implying that there must be little to no gallium in Earth's core. Metal-silicate partitioning experiments, however, have shown that gallium is a moderately siderophile element and should be therefore depleted in the mantle by core formation. Moreover, gallium concentrations in the mantle (4 ppm) are too high to be only brought by the late veneer; and neither pressure, nor temperature, nor silicate composition has a large enough effect on gallium partitioning to make it lithophile. Wemore » therefore systematically investigated the effect of core composition (light element content) on the partitioning of gallium by carrying out metal–silicate partitioning experiments in a piston–cylinder press at 2 GPa between 1673 K and 2073 K. Four light elements (Si, O, S, C) were considered, and their effect was found to be sufficiently strong to make gallium lithophile. The partitioning of gallium was then modeled and parameterized as a function of pressure, temperature, redox and core composition. A continuous core formation model was used to track the evolution of gallium partitioning during core formation, for various magma ocean depths, geotherms, core light element contents, and magma ocean composition (redox) during accretion. The only model for which the final gallium concentration in the silicate Earth matched the observed value is the one involving a light-element rich core equilibrating in a FeO-rich deep magma ocean (>1300 km) with a final pressure of at least 50 GPa. More specifically, the incorporation of S and C in the core provided successful models only for concentrations that lie far beyond their allowable cosmochemical or geophysical limits, whereas realistic O and Si amounts (less than 5 wt.%) in the core provided successful models for magma oceans deeper that 1300 km. In conclusion, these results offer a strong argument for an O- and Si-rich core, formed in a deep terrestrial magma ocean, along with oxidizing conditions.« less

  1. Water Content of Earth's Continental Mantle Is Controlled by the Circulation of Fluids or Melts

    NASA Technical Reports Server (NTRS)

    Peslier, Anne; Woodland, Alan B.; Bell, David R.; Lazarov, Marina; Lapen, Thomas J.

    2014-01-01

    A key mission of the ARES Directorate at JSC is to constrain models of the formation and geological history of terrestrial planets. Water is a crucial parameter to be measured with the aim to determine its amount and distribution in the interior of Earth, Mars, and the Moon. Most of that "water" is not liquid water per se, but rather hydrogen dissolved as a trace element in the minerals of the rocks at depth. Even so, the middle layer of differentiated planets, the mantle, occupies such a large volume and mass of each planet that when it is added at the planetary scale, oceans worth of water could be stored in its interior. The mantle is where magmas originate. Moreover, on Earth, the mantle is where the boundary between tectonic plates and the underlying asthenosphere is located. Even if mantle rocks in Earth typically contain less than 200 ppm H2O, such small quantities have tremendous influence on how easily they melt (i.e., the more water there is, the more magma is produced) and deform (the more water there is, the less viscous they are). These two properties alone emphasize that to understand the distribution of volcanism and the mechanism of plate tectonics, the water content of the mantle must be determined - Earth being a template to which all other terrestrial planets can be compared.

  2. A history of violence: Insights into post-accretionary heating in carbonaceous chondrites from volatile element abundances, Zn isotopes and water contents

    NASA Astrophysics Data System (ADS)

    Mahan, Brandon; Moynier, Frédéric; Beck, Pierre; Pringle, Emily A.; Siebert, Julien

    2018-01-01

    Carbonaceous chondrites (CCs) may have been the carriers of water, volatile and moderately volatile elements to Earth. Investigating the abundances of these elements, their relative volatility, and isotopes of state-change tracer elements such as Zn, and linking these observations to water contents, provide vital information on the processes that govern the abundances and isotopic signatures of these species in CCs and other planetary bodies. Here we report Zn isotopic data for 28 CCs (20 CM, 6 CR, 1 C2-ung, and 1 CV3), as well as trace element data for Zn, In, Sn, Tl, Pb, and Bi in 16 samples (8 CM, 6 CR, 1 C2-ung, and 1 CV3), that display a range of elemental abundances from case-normative to intensely depleted. We use these data, water content data from literature and Zn isotopes to investigate volatile depletions and to discern between closed and open system heating. Trace element data have been used to construct relative volatility scales among the elements for the CM and CR chondrites. From least volatile to most, the scale in CM chondrites is Pb-Sn-Bi-In-Zn-Tl, and for CR chondrites it is Tl-Zn-Sn-Pb-Bi-In. These observations suggest that heated CM and CR chondrites underwent volatile loss under different conditions to one another and to that of the solar nebula, e.g. differing oxygen fugacities. Furthermore, the most water and volatile depleted samples are highly enriched in the heavy isotopes of Zn. Taken together, these lines of evidence strongly indicate that heated CM and CR chondrites incurred open system heating, stripping them of water and volatiles concomitantly, during post-accretionary shock impact(s).

  3. Elemental characterization of Mt. Sinabung volcanic ash, Indonesia by Neutron Activation Analysis

    NASA Astrophysics Data System (ADS)

    Kusmartini, I.; Syahfitri, W. Y. N.; Kurniawati, S.; Lestiani, D. D.; Santoso, M.

    2017-06-01

    Mount Sinabung is a volcano located in North Sumatera, Indonesia which has been recorded not erupted since 1600. However in 2013 it has been erupted and cause of black thick smog, rain sand and volcanic ash. Volcanic ash containing trace elements material that can be utilized in various applications but still has potential danger of heavy metals. In order to obtain an elemental composition data of volcanic ash, the characterization of volcanic ash were carried out using Neutron Activation Analysis. The volcanic ash was taken from Mt. Sinabung eruption. Samples were irradiated at the rabbit system in the reactor G.A Siwabessy facilities with neutron flux ˜ 1013 n.cm-2.s-1 and then counted using HPGe detector. Method validation was carried out by SRM NIST Coal Fly Ash 1633b and NIST 2711a Montana II Soil with recovery values were in the range of 96-108% and 95-106% respectively. The results showed that major elements; Al, Na, Ca and Fe, concentrations were 8.7, 1.05, 2.98 and 7.44 %, respectively, minor elements K, Mg, Mn, Ti, V and Zn were 0.87%, 0.78%, 0.18%, 0.62%, 197.13 ppm and 109.35 ppm, respectively, heavy metals; As, Cr, Co and Sb, contents were 4.48, 11.75, 17.13 and 0.35 ppm, respectively while rare earth elements such as Ce, Eu, La, Nd, Sm, Yb were 45.33, 1.22, 19.63, 20.34, 3.86, and 2.57 ppm respectively. The results of the elemental contents of volcanic ash that has been obtained can be used as the scientific based data for volcanic material utilization by considering the economic potential of elements contained and also the danger of the heavy metals content.

  4. Correlation between evolution of inclusions and pitting corrosion in 304 stainless steel with yttrium addition.

    PubMed

    Shi, Weining; Yang, Shufeng; Li, Jingshe

    2018-03-19

    Effects of the evolution of inclusions on the pitting corrosion resistance of 304 stainless steel with different contents of the rare-earth element yttrium (Y) were studied using thermodynamic calculations, accelerated immersion tests, and electrochemical measurements. The experimental results showed that regular Y 2 O 3 inclusions demonstrated the best pitting resistance, followed in sequence by (Al,Mn)O inclusions, the composite inclusions, and irregular Y 2 O 3 inclusions. The pitting resistance first decreased, then increased, and then decreased again with increasing Y content, because sulfide inclusions were easily generated when the Y content was low and YN inclusions were easily generated at higher Y contents. The best pitting corrosion resistance was obtained for 304 stainless steel with addition of 0.019% Y.

  5. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    AL-Areqi, Wadeeah M., E-mail: walareqi@yahoo.com; Majid, Amran Ab., E-mail: walareqi@yahoo.com; Sarmani, Sukiman, E-mail: walareqi@yahoo.com

    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMPmore » and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of {sup 232}Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.« less

  6. The ESPAS e-infrastructure: Access to data from near-Earth space

    NASA Astrophysics Data System (ADS)

    Belehaki, Anna; James, Sarah; Hapgood, Mike; Ventouras, Spiros; Galkin, Ivan; Lembesis, Antonis; Tsagouri, Ioanna; Charisi, Anna; Spogli, Luca; Berdermann, Jens; Häggström, Ingemar; ESPAS Consortium

    2016-10-01

    ESPAS, the ;near-Earth space data infrastructure for e-science; is a data e-infrastructure facilitating discovery and access to observations, ground-based and space borne, and to model predictions of the near-Earth space environment, a region extending from the Earth's atmosphere up to the outer radiation belts. ESPAS provides access to metadata and/or data from an extended network of data providers distributed globally. The interoperability of the heterogeneous data collections is achieved with the adoption and adaption of the ESPAS data model which is built entirely on ISO 19100 series geographic information standards. The ESPAS data portal manages a vocabulary of space physics keywords that can be used to narrow down data searches to observations of specific physical content. Such content-targeted search is an ESPAS innovation provided in addition to the commonly practiced data selection by time, location, and instrument. The article presents an overview of the architectural design of the ESPAS system, of its data model and ontology, and of interoperable services that allow the discovery, access and download of registered data. Emphasis is given to the standardization, and expandability concepts which represent also the main elements that support the building of long-term sustainability activities of the ESPAS e-infrastructure.

  7. Laboratory Earth: Connecting Everything to Everything Else Online for Pre-college Educators

    NASA Astrophysics Data System (ADS)

    Gosselin, D.; Bonnstetter, R.; Yendra, S.; Slater, T.

    2007-12-01

    The Laboratory Earth professional development series, which has been funded by NASA, consists of three, three- credit hour, graduate level, distance-delivered, online courses designed for K- 8 (and above) educators. Currently, we have delivered two module-based courses, Laboratory Earth I: Earth and its Systems and Laboratory Earth II: Earth's Natural Resource Systems. A third course tentatively titled, Laboratory Earth: Earth's Changing Environments, is under development. Our objectives are to deliver a high quality professional development experience, improve participant's ability to understand and apply Earth system science concepts in their classroom, and to increase teacher's sense of belonging to a community. Each course consists of four modules that engage students using multiple strategies to meet a variety of learning styles. To document learning, content questions are used to focus the student on the concepts they will be learning throughout the course. These questions are also used to assess the progress the student has made toward learning the concepts from the beginning to the end of the course. Analysis of the responses to the content questions from Lab Earth I demonstrates significant knowledge gains from the beginning to the end of the course. Preliminary data also suggests that the extent of learning is higher in the 8-week version than it is in the 16-week version of the course. An implicit goal of the courses is to help participants focus on learning, not grades. Unfortunately, grades have to be issued. Our grading strategy has evolved to a system that uses the ability of students to master course content along with active participation and the on-time, quality completion of the grading elements in the course. Course content mastery can be demonstrated in a variety of ways and it is up to the student to choose the method that they would like to use. Methods include writing essays, creating presentations, preparing an oral journal, and developing concept maps. If tasks that a student submits are not complete, they are asked to revisit the assignment. The goal is for the student to be intrinsically motivated to learn the material and reduce the need for grades as a motivator and distract from their learning. We want everyone to work until they have the required concept knowledge and understanding. The combined results from STEBI-A (teacher efficacy for teaching science scale), LEO, (scale to assess teacher's sense of community within the course), and BES (Beliefs About Earth Science to assess the degree to which teachers enjoy teaching science) demonstrate statistically significant growth in teachers' sense of cohesion of the course and the value they place on teaching Earth science. The Laboratory Earth series is a key component of an initiative to create a collaborative online, distance delivered, masters degree program at UNL.

  8. Water inventories on Earth and Mars: Clues to atmosphere formation

    NASA Technical Reports Server (NTRS)

    Carr, M. H.

    1992-01-01

    Water is distributed differently on Earth and on Mars and the differences may have implications for the accretion of the two planets and the formation of their atmospheres. The Earth's mantle appears to contain at least several times the water content of the Martian mantle even accounting for differences in plate tectonics. One explanation is that the Earth's surface melted during accretion, as a result of development of a steam atmosphere, thereby allowing impact-devolitalized water at the surface to dissolve into the Earth's interior. In contrast, because of Mars' smaller size and greater distance from the Sun, the Martian surface may not have melted, so that the devolatilized water could not dissolve into the surface. A second possibility is suggested by the siderophile elements in the Earth's mantle, which indicates the Earth acquired a volatile-rich veneer after the core formed. Mars may have acquired a late volatile-rich veneer, but it did not get folded into the interior as with the Earth, but instead remained as a water rich veneer. This perception of Mars with a wet surface but dry interior is consistent with our knowledge of Mars' geologic history.

  9. Provenance and depositional history of continental slope sediments in the Southwestern Gulf of Mexico unraveled by geochemical analysis

    NASA Astrophysics Data System (ADS)

    Armstrong-Altrin, John S.; Machain-Castillo, María Luisa; Rosales-Hoz, Leticia; Carranza-Edwards, Arturo; Sanchez-Cabeza, Joan-Albert; Ruíz-Fernández, Ana Carolina

    2015-03-01

    The aim of this work is to constrain the provenance and depositional history of continental slope sediments in the Southwestern Gulf of Mexico (~1089-1785 m water depth). To achieve this, 10 piston sediment cores (~5-5.5 m long) were studied for mineralogy, major, trace and rare earth element geochemistry. Samples were analyzed at three core sections, i.e. upper (0-1 cm), middle (30-31 cm) and lower (~300-391 cm). The textural study reveals that the core sediments are characterized by silt and clay fractions. Radiocarbon dating of sediments for the cores at different levels indicated a maximum of ~28,000 year BP. Sediments were classified as shale. The chemical index of alteration (CIA) values for the upper, middle, and lower sections revealed moderate weathering in the source region. The index of chemical maturity (ICV) and SiO2/Al2O3 ratio indicated low compositional maturity for the core sediments. A statistically significant correlation observed between total rare earth elements (∑REE) versus Al2O3 and Zr indicated that REE are mainly housed in detrital minerals. The North American Shale Composite (NASC) normalized REE patterns, trace element concentrations such as Cr, Ni and V, and the comparison of REE concentrations in sediments and source rocks indicated that the study area received sediments from rocks intermediate between felsic and mafic composition. The enrichment factor (EF) results indicated that the Cd and Zn contents of the upper section sediments were influenced by an anthropogenic source. The trace element ratios and authigenic U content of the core sediments indicated the existence of an oxic depositional environment.

  10. Effect of H2O on metal-silicate partitioning of Ni, Co, V, Cr, Mn and Fe: Implications for the oxidation state of the Earth and Mars

    NASA Astrophysics Data System (ADS)

    Clesi, V.; Bouhifd, M. A.; Bolfan-Casanova, N.; Manthilake, G.; Fabbrizio, A.; Andrault, D.

    2016-11-01

    This study investigates the metal-silicate partitioning of Ni, Co, V, Cr, Mn and Fe during core mantle differentiation of terrestrial planets under hydrous conditions. For this, we equilibrated a molten hydrous CI chondrite model composition with various Fe-rich alloys in the system Fe-C-Ni-Co-Si-S in a multi-anvil over a range of P, T, fO2 and water content (5-20 GPa, 2073-2500 K, from 1 to 5 log units below the iron-wüstite (IW) buffer and for XH2O varying from 500 ppm to 1.5 wt%). By comparing the present experiments with the available data sets on dry systems, we observes that the effect of water on the partition coefficients of moderately siderophile elements is only moderate. For example, for iron we observed a decrease in the partition coefficient of Fe (Dmet/silFe) from 9.5 to 4.3, with increasing water content of the silicate melt, from 0 to 1.44 wt%, respectively. The evolution of metal-silicate partition coefficients of Ni, Co, V, Cr, Mn and Fe are modelled based on sets of empirical parameters. These empirical models are then used to refine the process of core segregation during accretion of Mars and the Earth. It appears that the likely presence of 3.5 wt% water on Mars during the core-mantle segregation could account for ∼74% of the FeO content of the Martian mantle. In contrast, water does not play such an important role for the Earth; only 4-6% of the FeO content of its mantle could be due to the water-induced Fe-oxidation, for a likely initial water concentration of 1.8 wt%. Thus, in order to reproduce the present-day FeO content of 8 wt% in the mantle, the Earth could initially have been accreted from a large fraction (between 85% and 90%) of reducing bodies (similar to EH chondrites), with 10-15% of the Earth's mass likely made of more oxidized components that introduced the major part of water and FeO to the Earth. This high proportion of enstatite chondrites in the original constitution of the Earth is consistent with the 17O,48Ca,50Ti,62Ni and 90Mo isotopic study by Dauphas et al. (2014). If we assume that the CI-chondrite was oxidized during accretion, its intrinsically high water content suggests a maximum initial water concentration in the range of 1.2-1.8 wt% for the Earth, and 2.5-3.5 wt% for Mars.

  11. Oceanographic Analysis of Sun Glint Images Taken on Space Shuttle Mission STS 41-G.

    DTIC Science & Technology

    1986-03-01

    10. SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASK WORK UNIT ELEMENT NO. NO. NO. ACCESSION NO. ?I TITLE (Include Security Ciassification) OCEANOGRAPHIC...CONTENTS le INTRJODUCTION --- ---. m.--- --..-- --.-- -- -- -- --- -- ---.-. II. WESTERN MEDITERRANEAN OCEANOGRAPHIC OVERVIEV - --------------- 10. A...By computing the arc tangent of 128 n.m./125 n.m. a tilt angle of 45.7’ was approximated for the camera lens. Two simplifications were made. Earth

  12. The Synthesis and Characterization of Some Rare Earth Arsenides.

    DTIC Science & Technology

    1987-09-10

    particular, handling contaminants such as sodium , calcium and potassium can be monitored as well as hydrogen and oxygen content from oxide and hydroxide...trace quantities. Exceptional sensitivities (ppm) can be obtained for easily ionizable elements such as sodium , calcium, potassium, etc. This method of...holmium then reacts with the silica container wall, forming silicide and oxide products. The Nd melt reacts with the container as well. In the longer

  13. Volatile elements in and on lunar volcanic glasses: What do they tell us about lunar genesis?

    NASA Technical Reports Server (NTRS)

    Koeberl, C.

    1984-01-01

    There are good reasons to believe that lunar volcanic glasses originated from a deep interior source. The presence of a thin layer of surface correlated elements on these glasses may indicate that the Moon has some reservoirs that are enriched in volatiles. Since the glasses themselves do not show similar enrichment, the source should be of limited extent. Three scenarios are advanced for the origin of these elements. The mechanism for lunar volcanism differs from the mechanism for volcanism on Earth since the former produces bubbling and the latter explosive fountaining. From the condensation behavior of the volatile compounds, which leads to heterogeneous condensation, it is concluded that comparing element ratios of surface correlated elements gives little sense. It seems as if the volatile reservoirs are of rather limited extent and that they do not enlarge the volatile content of the bulk Moon significantly.

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

    USGS Publications Warehouse

    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.

  15. Spatial variability and geochemistry of rare earth elements in soils from the largest uranium-phosphate deposit of Brazil.

    PubMed

    Cunha, Cleyton Saialy Medeiros; da Silva, Ygor Jacques Agra Bezerra; Escobar, Maria Eugenia Ortiz; do Nascimento, Clístenes Williams Araújo

    2018-02-22

    The Itataia uranium-phosphate deposit is the largest uranium reserve in Brazil. Rare earth elements (REEs) are commonly associated with phosphate deposits; however, there are no studies on the concentrations of REEs in soils of the Itataia deposit region. Thus, the objective of the research was to evaluate the concentration and spatial variability of REEs in topsoils of Itataia phosphate deposit region. In addition, the influence of soil properties on the geochemistry of REEs was investigated. Results showed that relatively high mean concentrations (mg kg -1 ) of heavy REEs (Gd 6.01; Tb 1.25; Ho 1.15; Er 4.05; Tm 0.64; Yb 4.61; Lu 0.65) were found in surface soils samples. Soil properties showed weak influence on the geochemical behavior of REEs in soils, except for the clay content. On the other hand, parent material characteristics, such as P and U, had strong influence on REEs concentrations. Spatial distribution patterns of REEs in soils are clearly associated with P and U contents. Therefore, geochemical surveys aiming at the delineation of ore-bearing zones in the region can benefit from our data. The results of this work reinforce the perspective for co-mining of P, U and REEs in this important P-U reserve.

  16. Accumulation of rare earth elements by siderophore-forming Arthrobacter luteolus isolated from rare earth environment of Chavara, India.

    PubMed

    Emmanuel, E S Challaraj; Ananthi, T; Anandkumar, B; Maruthamuthu, S

    2012-03-01

    In this study, Arthrobacter luteolus, isolated from rare earth environment of Chavara (Quilon district, Kerala, India), were found to produce catechol-type siderophores. The bacterial strain accumulated rare earth elements such as samarium and scandium. The siderophores may play a role in the accumulation of rare earth elements. Catecholate siderophore and low-molecular-weight organic acids were found to be present in experiments with Arthrobacter luteolus. The influence of siderophore on the accumulation of rare earth elements by bacteria has been extensively discussed.

  17. Distribution behavior of uranium, neptunium, rare-earth elements ( Y, La, Ce, Nd, Sm, Eu, Gd) and alkaline-earth metals (Sr,Ba) between molten LiClKCI eutectic salt and liquid cadmium or bismuth

    NASA Astrophysics Data System (ADS)

    Kurata, M.; Sakamura, Y.; Hijikata, T.; Kinoshita, K.

    1995-12-01

    Distribution coefficients of uranium neptunium, eight rare-earth elements (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) and two alkaline-earth metals (Sr and Ba) between molten LiCl-KCI eutectic salt and either liquid cadmium or bismuth were measured at 773 K. Separation factors of trivalent rare-earth elements to uranium or neptunium in the LiCl-KCl/Bi system were by one or two orders of magnitude larger than those in the LiCl-KCl/Cd system. On the contrary, the separation factors of alkaline-earth metals and divalent rare-earth elements to trivalent rare-earth elements were by one or two orders of magnitude smaller in the LiCl-KCl/Bi system.

  18. Alkali element constraints on Earth-Moon relations

    NASA Technical Reports Server (NTRS)

    Norman, M. D.; Drake, M. J.; Jones, J. H.

    1994-01-01

    Given their range of volatilities, alkali elements are potential tracers of temperature-dependent processes during planetary accretion and formation of the Earth-Moon system. Under the giant impact hypothesis, no direct connection between the composition of the Moon and the Earth is required, and proto-lunar material does not necessarily experience high temperatures. Models calling for multiple collisions with smaller planetesimals derive proto-lunar materials mainly from the Earth's mantle and explicitly invoke vaporization, shock melting and volatility-related fractionation. Na/K, K/Rb, and Rb/Cs should all increase in response to thermal volatization, so theories which derive the Moon substantially from Earth's mantle predict these ratios will be higher in the Moon than in the primitive mantle of the Earth. Despite the overall depletion of volatile elements in the Moon, its Na/K and K/Rb are equal to or less than those of Earth. A new model presented here for the composition of Earth's continental crust, a major repository of the alkali elements, suggests the Rb/Cs of the Moon is also less than that of Earth. Fractionation of the alkali elements between Earth and Moon are in the opposite sense to predictions based on the relative volatilities of these elements, if the Moon formed by high-T processing of Earth's mantle. Earth, rather than the Moon, appears to carry a signature of volatility-related fractionation in the alkali elements. This may reflect an early episode of intense heating on Earth with the Moon's alkali budget accreting from cooler material.

  19. Quantification of seasonal biomass effects on cosmic-ray soil water content determination

    NASA Astrophysics Data System (ADS)

    Baatz, R.; Bogena, H. R.; Hendricks Franssen, H.; Huisman, J. A.; Qu, W.; Montzka, C.; Korres, W.; Vereecken, H.

    2013-12-01

    The novel cosmic-ray soil moisture probes (CRPs) measure neutron flux density close to the earth surface. High energy cosmic-rays penetrate the Earth's atmosphere from the cosmos and become moderated by terrestrial nuclei. Hydrogen is the most effective neutron moderator out of all chemical elements. Therefore, neutron flux density measured with a CRP at the earth surface correlates inversely with the hydrogen content in the CRP's footprint. A major contributor to the amount of hydrogen in the sensor's footprint is soil water content. The ability to measure changes in soil water content within the CRP footprint at a larger-than-point scale (~30 ha) and at high temporal resolution (hourly) make these sensors an appealing measurement instrument for hydrologic modeling purposes. Recent developments focus on the identification and quantification of major uncertainties inherent in CRP soil moisture measurements. In this study, a cosmic-ray soil moisture network for the Rur catchment in Western Germany is presented. It is proposed to correct the measured neutron flux density for above ground biomass yielding vegetation corrected soil water content from cosmic-ray measurements. The correction for above ground water equivalents aims to remove biases in soil water content measurements on sites with high seasonal vegetation dynamics such as agricultural fields. Above ground biomass is estimated as function of indices like NDVI and NDWI using regression equations. The regression equations were obtained with help of literature information, ground-based control measurements, a crop growth model and globally available data from the Moderate Resolution Imaging Spectrometer (MODIS). The results show that above ground biomass could be well estimated during the first half of the year. Seasonal changes in vegetation water content yielded biases in soil water content of ~0.05 cm3/cm3 that could be corrected for with the vegetation correction. The vegetation correction has particularly high potential when applied at long term cosmic-ray monitoring sites and the cosmic-ray rover.

  20. The effect of environmentally friendly hot-dipping auxiliary on the morphology of alloy coatings

    NASA Astrophysics Data System (ADS)

    Chen, Suhong; Guo, Kai; Zhu, Yi; Gao, Feng; Han, Zhijun

    2017-10-01

    Zn-Al-Mg-RE hot-dip alloy coatings which prepared by the environmentally friendly plating auxiliary were investigated by X-ray diffraction (XRD), SEM analysis and salt spray measurement. Significant variation in coating surface morphology and element content are observed with increasing content of Al and Mg in this paper. A reinforced ternary eutectic Zn-Al-MgZn2 is confirmed which attribute to improvement metallographic structure derived from certain ternary eutectic reaction in alloy solidification. For Mg-containing coatings, the enhanced corrosion resistance is observed by corrosion resistance test in salt spray at 35°C with 5% NaCl in terms of corrosion weight changes. It is found that the incorporation of 3 wt.% Mg and 0.1 wt.% rare earth element in to Zn-Al-Mg-RE bath caused structural refinement of the crystal and also helped to achieve excellent surface morphology.

  1. Accumulation and fractionation of rare earth elements (REEs) in the naturally grown Phytolacca americana L. in southern China.

    PubMed

    Yuan, Ming; Liu, Chang; Liu, Wen-Shen; Guo, Mei-Na; Morel, Jean Louis; Huot, Hermine; Yu, Hong-Jie; Tang, Ye-Tao; Qiu, Rong-Liang

    2018-04-16

    The widespread use of rare earth elements (REEs) has resulted in problems for soil and human health. Phytolacca americana L. is a herbaceous plant widely distributed in Dingnan county of Jiangxi province, China, which is a REE mining region (ion absorption rare earth mine) and the soil has high levels of REEs. An investigation of REE content of P. americana growing naturally in Dingnan county was conducted. REE concentrations in the roots, stems, and leaves of P. americana and in their rhizospheric soils were determined. Results showed that plant REEs concentrations varied among the sampling sites and can reach 1040 mg/kg in the leaves. Plant REEs concentrations decreased in the order of leaf > root > stem and all tissues were characterized by a light REE enrichment and a heavy REE depletion. However, P. americana exhibited preferential accumulation of light REEs during the absorption process (from soil to root) and preferential accumulation of heavy REEs during the translocation process (from stem to leaf). The ability of P. americana to accumulate high REEs in the shoot makes it a potential candidate for understanding the absorption mechanisms of REEs and for the phytoremediation of REEs contaminated soil.

  2. Geochemical associations between fluorite mineralization and A-type shoshonitic magmatism in the Keban-Elazig area, East Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Akgul, Bunyamin

    2015-11-01

    Keban fluorite mineralizations are closely related Coniacian-Campanian subvolcanics intruded into Permian-Triassic Keban metamorphites; this event caused pyrometasomatic, porphyry, and vein-type Pb-Zn-Ag, Cu, W, and Pb-Zn-Ag-Mo-F mineralizations. These rocks are syenitic and syenomonzonitic in composition and have high Al2O3, alkali (Na2O + K2O), FeO*/MgO, Zr, Nb, Ta, Ga, Rb, Y, and rare earth element (REE) contents. They are A-type, metaluminous, and all fall in the shoshonitic series field in K2O vs SiO2 and Th/Yb vs Ta/Yb diagrams. The trace element contents and discriminations indicate that the Keban syenitoids were derived from lithospheric mantle metasomatized by oceanic-crust/sediment fluids. The metal and halogen contents of the Keban mineralizations apparently originated from metasomatized mantle and were transported to the crust by syenitoid magmas. Clear resemblances in chondrite-normalized REE patterns, LREE-HREE partionation, and high LILE contents of the magmatics and fluorites indicate a close kinship between the syenitoids and fluorite mineralizations. The HFSE contents of the fluorites are lower than those of the magmatics, as HFSEs are not soluble in aqueous fluids. The fluorites are products of early-phase alkali magmatism (LREE > HREE). The high contents of Rb, Sr, and Ba of fluorites are inherited from the magma, which also has very high contents of these elements. In Sc-∑REE, (La/Yb)n-(Eu/Eu*)n and (Tb/La)n-(Tb/Ca)n diagrams, Keban fluorites fall into distinct areas from Akcakisla-Akdagmadeni and Celikhan-Adiyaman fluorites.

  3. Resource potential for commodities in addition to Uranium in sandstone-hosted deposits: Chapter 13

    USGS Publications Warehouse

    Breit, George N.

    2016-01-01

    Sandstone-hosted deposits mined primarily for their uranium content also have been a source of vanadium and modest amounts of copper. Processing of these ores has also recovered small amounts of molybdenum, rhenium, rare earth elements, scandium, and selenium. These deposits share a generally common origin, but variations in the source of metals, composition of ore-forming solutions, and geologic history result in complex variability in deposit composition. This heterogeneity is evident regionally within the same host rock, as well as within districts. Future recovery of elements associated with uranium in these deposits will be strongly dependent on mining and ore-processing methods.

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

    USGS Publications Warehouse

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

    1958-01-01

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

  5. The Not-So-Rare Earths.

    ERIC Educational Resources Information Center

    Muecke, Gunter K.; Moller, Peter

    1988-01-01

    Describes the characteristics of rare earth elements. Details the physical chemistry of rare earths. Reviews the history of rare earth chemistry and mineralogy. Discusses the mineralogy and crystallography of the formation of rare earth laden minerals found in the earth's crust. Characterizes the geologic history of rare earth elements. (CW)

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

    NASA Technical Reports Server (NTRS)

    Fritsche, H.

    1983-01-01

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

  7. Recovering heavy rare earth metals from magnet scrap

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ott, Ryan T.; McCallum, Ralph W.; Jones, Lawrence L.

    A method of treating rare earth metal-bearing permanent magnet scrap, waste or other material in a manner to recover the heavy rare earth metal content separately from the light rare earth metal content. The heavy rare earth metal content can be recovered either as a heavy rare earth metal-enriched iron based alloy or as a heavy rare earth metal based alloy.

  8. Siderophile Volatile Element Partitioning during Core Formation.

    NASA Astrophysics Data System (ADS)

    Loroch, D. C.; Hackler, S.; Rohrbach, A.; Klemme, S.

    2017-12-01

    Since the nineteen sixties it is known, that the Earth's mantle is depleted relative to CI chondrite in numerous elements as a result of accretion and core-mantle differentiation. Additionally, if we take the chondritic composition as the initial solar nebular element abundances, the Earth lacks 85 % of K and up to 98 % of other volatiles. However one potentially very important group of elements has received considerably less attention in this context and these elements are the siderophile but volatile elements (SVEs). SVEs perhaps provide important information regarding the timing of volatile delivery to Earth. Especially for the SVEs the partitioning between metal melt and silicate melt (Dmetal/silicate) at core formation conditions is poorly constrained, never the less they are very important for most of the core formation models. This study is producing new metal-silicate partitioning data for a wide range of SVEs (S, Se, Te, Tl, Ag, As, Au, Cd, Bi, Pb, Sn, Cu, Ge, Zn, In and Ga) with a focus on the P, T and fO2dependencies. The initial hypothesis that we are aiming to test uses the accretion of major portions of volatile elements while the core formation was still active. The key points of this study are: - What are the effects of P, T and fO2 on SVE metal-silicate partioning? - What is the effect of compositional complexity on SVE metal-silicate partioning? - How can SVE's D-values fit into current models of core formation? The partitioning experiments will be performed using a Walker type multi anvil apparatus in a pressure range between 10 and 20 GPa and temperatures of 1700 up to 2100 °C. To determine the Dmetal/silicate values we are using a field emission high-resolution JEOL JXA-8530F EPMA for major elements and a Photon Machines Analyte G2 Excimer laser (193 nm) ablation system coupled to a Thermo Fisher Element 2 single-collector ICP-MS (LA-ICP-MS) for the trace elements. We recently finished the first sets of experiments and can provide the corresponding datasets. Based on the general understanding of Dmetal/silicate values we expect to depend on the composition, in this particular case this means a variation in sulfur and carbon content of the core composition, and also a change of the redox conditions. The major goal however is to derive a model of core formation on Earth that includes and also explains the SVEs.

  9. Real World of Industrial Chemistry: Technology of the Rare Earths.

    ERIC Educational Resources Information Center

    Kremers, Howard E.

    1985-01-01

    The 17 rare earth elements account for one-fifth of the 83 naturally occurring elements and collectively rank as the 22nd most abundant "element." Properties of these elements (including their chemical similarity), their extraction from the earth, and their uses are discussed. (JN)

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

    PubMed

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

    2012-08-01

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

  11. Synthesis and Characterization of an Earth-Abundant Cu2BaSn(S,Se)4 Chalcogenide for Photoelectrochemical Cell Application.

    PubMed

    Shin, Donghyeop; Ngaboyamahina, Edgard; Zhou, Yihao; Glass, Jeffrey T; Mitzi, David B

    2016-11-17

    Cu 2 BaSnS 4-x Se x films consisting of earth-abundant metals have been examined for photocathode application. Films with different Se contents (i.e., Cu 2 BaSnS 4-x Se x with x ≤ 2.4) were synthesized using a cosputter system with post-deposition sulfurization/selenization annealing treatments. Each film adopts a trigonal P3 1 crystal structure, with progressively larger lattice constants and with band gaps shifting from 2.0 to 1.6 eV, as more Se substitutes for S in the parent compound Cu 2 BaSnS 4 . Given the suitable bandgap and earth-abundant elements, the Cu 2 BaSnS 4-x Se x films were studied as prospective photocathodes for water splitting. Greater than 6 mA/cm 2 was obtained under illumination at -0.4 V versus reversible hydrogen electrode for Pt/Cu 2 BaSnS 4-x Se x films with ∼60% Se content (i.e., x = 2.4), whereas a bare Cu 2 BaSnS 4-x Se x (x = 2.4) film yielded ∼3 mA/cm 2 at -0.4 V/RHE.

  12. Solubility of oxygen in liquid Fe at high pressure and consequences for the early differentiation of Earth and Mars

    NASA Astrophysics Data System (ADS)

    Rubie, D. C.; Gessmann, C. K.; Frost, D. J.

    2003-04-01

    Knowledge of the solubility of oxygen in liquid iron enables the partitioning of oxygen between metal and silicates and the oxidation state of residual silicates to be constrained during core formation in planetary bodies. We have determined oxygen solubility experimentally at 5--23 GPa, 2100--2700 K and oxygen fugacities 1--4 log units below the iron-wüstite buffer in samples of liquid Ni-Fe alloy contained in magnesiowüstite capsules using a multianvil apparatus. Results show that oxygen solubility increases with increasing temperature but decreases slightly with increasing pressure over the range of experimental conditions, at constant oxygen fugacity. Using an extrapolation of the results to higher pressures and temperatures, we have modeled the geochemical consequences of metal-silicate separation in magma oceans in order to explain the contrasting FeO contents of the mantles of Earth and Mars. We assume that both Earth and Mars accreted originally from material with a chondritic composition; because the initial oxidation state is uncertain, we vary this parameter by defining the initial oxygen content. Two metal-silicate fractionation models are considered: (1) Metal and silicate are allowed to equilibrate at fictive conditions that approximate the pressure and temperature at the base of a magma ocean. (2) The effect of settling Fe droplets in a magma ocean is determined using a simple polybaric metal-silicate fractionation model. We assume that the temperature at the base of a magma ocean is close to the peridotite liquidus. In the case of Earth, high temperatures in a magma ocean with a depth >1200 km would have resulted in significant quantities of oxygen dissolving in the liquid metal with the consequent extraction of FeO from the residual silicate. In contrast, on Mars, even if the magma ocean extended to the depth of the current core-mantle boundary, temperatures would not have been sufficiently high for oxygen solubility in liquid metal to be significant. The results show that Earth and Mars could have accreted from similar material, with an initial FeO content around 18 wt%. On Earth, oxygen was extracted from silicates by the segregating metal during core formation, leaving the mantle with its present FeO content of ˜8 wt%. On Mars, in contrast, the segregating metal extracted little or no oxygen and left the FeO content unaltered at ˜18 wt%. A consequence of this model is that oxygen should be an important light element in the Earth's core but not in the Martian core.

  13. MICROBIALLY MEDIATED LEACHING OF RARE EARTH ELEMENTS FROM RECYCLABLE MATERIALS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Reed, D. W.; Fujita, Y.; Daubaras, D. L.

    2016-09-01

    Bioleaching offers a potential approach for recovery of rare earth elements (REE) from recyclable materials, such as fluorescent lamp phosphors or degraded industrial catalysts. Microorganisms were enriched from REE-containing ores and recyclable materials with the goal of identifying strains capable of extracting REE from solid materials. Over 100 heterotrophic microorganisms were isolated and screened for their ability to produce organic acids capable of leaching REE. The ten most promising isolates were most closely related to Pseudomonas, Acinetobacter and Talaromyces. Of the acids produced, gluconic acid appeared to be the most effective at leaching REE (yttrium, lanthanum, cerium, europium, and terbium)more » from retorted phosphor powders (RPP), fluidized cracking catalyst (FCC), and europium-doped yttrium oxide (YOEu). We found that an Acinetobacter isolates, BH1, was the most capable strain and able to leach 33% of the total REE content from the FCC material. These results support the continuing evaluation of gluconic acid-producing microbes for large-scale REE recovery from recyclable materials.« less

  14. Comparative studies on the concentration of rare earth elements and heavy metals in the atmospheric particulate matter in Beijing, China, and in Delft, The Netherlands.

    PubMed

    Wang, C X; Zhu, W; Peng, A; Guichreit, R

    2001-05-01

    Atmospheric particulate matter (APM) was collected at three sampling sites in Beijing, China, from February to June 1998. The concentrations of rare earth elements (REE) and cobalt (Co), zinc (Zn), copper (Cu), cadmium (Cd) and lead (Pb) in the APM were determined by inductively coupled plasma mass spectrometry (ICP-MS). The results obtained in Beijing, China, were compared to that obtained in Delft, the Netherlands, in 1997. The influence of coal combustion was considered. The results demonstrated that the content of APM, the concentrations of REE and Co, Zn, Cd, Pb in the APM in Beijing, China, were higher than that in Delft, the Netherlands. From the ratios of La to Ce, and La to Sm, which may be used as tracers for the origin of the REE, it is concluded that the origins of REE in China differ from those in the Netherlands.

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

    USGS Publications Warehouse

    Lichte, F.E.; Meier, A.L.; Crock, J.G.

    1987-01-01

    A method of analysis of geological materials for the determination of the rare-earth elements using the Inductively coupled plasma mass spectrometric technique (ICP-MS) has been developed. Instrumental parameters and factors affecting analytical results have been first studied and then optimized. Samples are analyzed directly following an acid digestion, without the need for separation or preconcentration with limits of detection of 2-11 ng/g, precision of ?? 2.5% relative standard deviation, and accuracy comparable to inductively coupled plasma emission spectrometry and instrumental neutron activation analysis. A commercially available ICP-MS instrument is used with modifications to the sample introduction system, torch, and sampler orifice to reduce the effects of high salt content of sample solutions prepared from geologic materials. Corrections for isobaric interferences from oxide ions and other diatomic and triatomic ions are made mathematically. Special internal standard procedures are used to compensate for drift in metahmetal oxide ratios and sensitivity. Reference standard values are used to verify the accuracy and utility of the method.

  16. Rare Earth Element Concentration of Wyoming Thermal Waters Update

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Quillinan, Scott; Nye, Charles; Neupane, Hari

    Updated version of data generated from rare earth element investigation of produced waters. These data represent major, minor, trace, isotopes, and rare earth element concentrations in geologic formations and water associated with oil and gas production.

  17. 2nd International Symposium on Fundamental Aspects of Rare-earth Elements Mining and Separation and Modern Materials Engineering (REES-2015)

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

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

  18. Accumulation of alkaline earth metals by the green macroalga Bryopsis maxima.

    PubMed

    Takahashi, Shigekazu; Aizawa, Kyoko; Nakamura, Saki; Nakayama, Katsumi; Fujisaki, Shingo; Watanabe, Soichiro; Satoh, Hiroyuki

    2015-04-01

    Twenty-five days after the disaster at the Fukushima Daiichi nuclear power plant in 2011, we collected samples of the green macroalga Bryopsis maxima from the Pacific coast of Japan. Bryopsis maxima is a unicellular, multinuclear, siphonous green macroalga. Radiation analysis revealed that B. maxima emitted remarkably high gamma radiation of (131)I, (134)Cs, (137)Cs, and (140)Ba as fission products of (235)U. Interestingly, B. maxima contained naturally occurring radionuclides derived from (226)Ra and (228)Ra. Analysis of element content revealed that B. maxima accumulates many ocean elements, especially high quantities of the alkaline earth metals Sr (15.9 g per dry-kg) and Ba (3.79 g per dry-kg), whereas Ca content (12.5 g per dry-kg) was lower than that of Sr and only 61 % of the mean content of 70 Japanese seaweed species. Time-course analysis determined the rate of radioactive (85)Sr incorporation into thalli to be approximately 0.13 g Sr per dry-kg of thallus per day. Subcellular fractionation of B. maxima cells showed that most of the (85)Sr was localized in the soluble fraction, predominantly in the vacuole or cytosol. Given that (85)Sr radioactivity was permeable through a dialysis membrane, the (85)Sr was considered to be a form of inorganic ion and/or bound with a small molecule. Precipitation analysis with sodium sulfate showed that more than 70% of the Sr did not precipitate as SrSO4, indicating that a proportion of the Sr may bind with small molecules in B. maxima.

  19. Geochemistry of the Neoproterozoic metabasic rocks from the Negele area, southern Ethiopia: Tectonomagmatic implications

    NASA Astrophysics Data System (ADS)

    Yihunie, Tadesse; Adachi, Mamoru; Yamamoto, Koshi

    2006-03-01

    Neoproterozoic metabasic rocks along with metasediments and ultramafic rocks constitute the Kenticha and Bulbul lithotectonic domains in the Negele area. They occur as amphibolite and amphibole schist in the Kenticha, and amphibole schist and metabasalt in the Bulbul domains. These rocks are dominantly basaltic in composition and exhibit low-K tholeiitic characteristics. They are slightly enriched in large ion lithophile (LIL) and light rare earth (LRE) elements and depleted in high field strength (HFS) and heavy rare earth (HRE) elements. They exhibit chemical characteristics similar to back-arc basin and island-arc basalts, but include a few samples with slightly higher Y, Zr and Nb contents. Initial Sr isotopic ratios and ɛNd values for the Kenticha metabasic rocks range from 0.7048 to 0.7051 and from 4.7 to 9.6 whereas for the Bulbul metabasic rocks they range from 0.7032 to 0.7055 and from -0.1 to 5.5, respectively. The trace elements and Sr-Nd isotope compositions of samples from the Kenticha and Bulbul domains suggest similar, but isotopically heterogeneous magma sources. The magma is inferred to have derived from depleted source with a contribution from an enriched mantle source component.

  20. Formation of Hadean granites by melting of igneous crust

    NASA Astrophysics Data System (ADS)

    Burnham, A. D.; Berry, A. J.

    2017-06-01

    The oldest known samples of Earth, with ages of up to 4.4 Gyr, are detrital zircon grains in meta-sedimentary rocks of the Jack Hills in Australia. These zircons offer insights into the magmas from which they crystallized, and, by implication, igneous activity and tectonics in the first 500 million years of Earth’s history, the Hadean eon. However, the compositions of these magmas and the relative contributions of igneous and sedimentary components to their sources have not yet been resolved. Here we compare the trace element concentrations of the Jack Hills zircons to those of zircons from the locality where igneous (I-) and sedimentary (S-) type granites were first distinguished. We show that the Hadean zircons crystallized predominantly from I-type magmas formed by melting of a reduced, garnet-bearing igneous crust. Further, we propose that both the phosphorus content of zircon and the ratio of phosphorus to rare earth elements can be used to distinguish between detrital zircon grains from I- and S-type sources. These elemental discriminants provide a new geochemical tool to assess the relative contributions of primeval magmatism and melting of recycled sediments to the continents over geological time.

  1. Geochemistry of carbonatites of the Tomtor massif

    USGS Publications Warehouse

    Kravchenko, S.M.; Czamanske, G.; Fedorenko, V.A.

    2003-01-01

    Carbonatites compose sheet bodies in a 300-m sequence of volcanic lamproites, as well as separate large bodies at depths of >250-300 m. An analysis of new high-precision data on concentrations of major, rare, and rare earth elements in carbonatites shows that these rocks were formed during crystallization differentiation of a carbonatite magma, which resulted in enrichment of the later melt fractions in rare elements and was followed by autometasomatic and allometasomatic hydrothermal processes. Some independent data indicate that the main factor of ore accumulation in the weathered rock zone (also known as the "lower ore horizon" comprising metasomatized volcanics with interbedded carbonatites) was hydrothermal addition of Nb and REEs. The giant size of the Tomtor carbonatite-nepheline syenite massif caused advanced magma differentiation, extensive postmagmatic metasomatism and recrystallization of host rocks, and strong enrichment of carbonatites in incompatible rare and rare earth elements (except for Ta, Zr, Ti, K, and Rb) compared to the rocks of many other carbonatite massifs. We suggest that a wide range of iron contents in carbonatites-2 can be related to extensive magnetite fractionation at the magmatic stage in different parts of the huge massif. Copyright ?? 2003 by MAIK "Nauka/Interperiodica" (Russia).

  2. Two main and a new type rare earth elements in Mg alloys: A review

    NASA Astrophysics Data System (ADS)

    Kong, Linghang

    2017-09-01

    Magnesium (Mg) alloys stand for the lightest structure engineering materials. Moreover, the strengthening of Mg alloys in ductility, toughness and corrosion predominates their wide applications. With adding rare earth elements in Mg, the mechanical properties will be improved remarkably, especially their plasticity and strength. A brief overview of the addition of rare earth elements for Mg alloys is shown. The basic mechanisms of strengthening Mg alloys with rare earth elements are reviewed, including the solid solution strengthening, grain refinement and long period stacking ordered (LPSO) phase. Furthermore, the available rare earth elements are summarized by type, chemical or physical effects and other unique properties. Finally, some challenge problems that the research is facing and future expectations of ra-re-earth Mg alloys are stated and discussed.

  3. Investigating Rare Earth Element Systematics in the Marcellus Shale

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  4. Inert-Gas Condensed Co-W Nanoclusters: Formation, Structure and Magnetic Properties

    NASA Astrophysics Data System (ADS)

    Golkar-Fard, Farhad Reza

    Rare-earth permanent magnets are used extensively in numerous technical applications, e.g. wind turbines, audio speakers, and hybrid/electric vehicles. The demand and production of rare-earth permanent magnets in the world has in the past decades increased significantly. However, the decrease in export of rare-earth elements from China in recent time has led to a renewed interest in developing rare-earth free permanent magnets. Elements such as Fe and Co have potential, due to their high magnetization, to be used as hosts in rare-earth free permanent magnets but a major challenge is to increase their magnetocrystalline anisotropy constant, K1, which largely drives the coercivity. Theoretical calculations indicate that dissolving the 5d transition metal W in Fe or Co increases the magnetocrystalline anisotropy. The challenge, though, is in creating a solid solution in hcp Co or bcc Fe, which under equilibrium conditions have negligible solubility. In this dissertation, the formation, structure, and magnetic properties of sub-10 nm Co-W clusters with W content ranging from 4 to 24 atomic percent were studied. Co-W alloy clusters with extended solubility of W in hcp Co were produced by inert gas condensation. The different processing conditions such as the cooling scheme and sputtering power were found to control the structural state of the as-deposited Co-W clusters. For clusters formed in the water-cooled formation chamber, the mean size and the fraction crystalline clusters increased with increasing power, while the fraction of crystalline clusters formed in the liquid nitrogen-cooled formation chamber was not as affected by the sputtering power. For the low W content clusters, the structural characterization revealed clusters predominantly single crystalline hcp Co(W) structure, a significant extension of W solubility when compared to the equilibrium solubility, but fcc Co(W) and Co3W structures were observed in very small and large clusters, respectively. At high W content, clusters with hcp Co(W), fcc Co(W) or Co3W structures were observed. The magnetic measurements at 10 K and 300 K revealed that the coercivity, saturation magnetization and magnetocrystalline anisotropy of the clusters formed in the water-cooled formation chamber were higher than for clusters formed in the liquid nitrogen-cooled formation chamber. The coercivity and magnetocrystalline anisotropy of the clusters increased as long as W was dissolved into the hcp Co structure. With increasing fraction of Co3W and fcc Co(W) clusters, as observed in the high-W content sample, the magnetic properties deteriorated significantly. The highest coercivity and magnetocrystalline anisotropy of 893 Oe and 3.9 x 106 ergs/cm3, respectively, was obtained at 10 K for the 5 at.% W clusters sputtered at 150 W in the water-cooled formation chamber.

  5. Determination of rare earth elements in tomato plants by inductively coupled plasma mass spectrometry techniques.

    PubMed

    Spalla, S; Baffi, C; Barbante, C; Turetta, C; Turretta, C; Cozzi, G; Beone, G M; Bettinelli, M

    2009-10-30

    In recent years identification of the geographical origin of food has grown more important as consumers have become interested in knowing the provenance of the food that they purchase and eat. Certification schemes and labels have thus been developed to protect consumers and genuine producers from the improper use of popular brand names or renowned geographical origins. As the tomato is one of the major components of what is considered to be the healthy Mediterranean diet, it is important to be able to determine the geographical origin of tomatoes and tomato-based products such as tomato sauce. The aim of this work is to develop an analytical method to determine rare earth elements (RRE) for the control of the geographic origin of tomatoes. The content of REE in tomato plant samples collected from an agricultural area in Piacenza, Italy, was determined, using four different digestion procedures with and without HF. Microwave dissolution with HNO3 + H2O2 proved to be the most suitable digestion procedure. Inductively coupled plasma quadrupole mass spectrometry (ICPQMS) and inductively coupled plasma sector field plasma mass spectrometry (ICPSFMS) instruments, both coupled with a desolvation system, were used to determine the REE in tomato plants in two different laboratories. A matched calibration curve method was used for the quantification of the analytes. The detection limits (MDLs) of the method ranged from 0.03 ng g(-1) for Ho, Tm, and Lu to 2 ng g(-1) for La and Ce. The precision, in terms of relative standard deviation on six replicates, was good, with values ranging, on average, from 6.0% for LREE (light rare earth elements) to 16.5% for HREE (heavy rare earth elements). These detection limits allowed the determination of the very low concentrations of REE present in tomato berries. For the concentrations of REE in tomato plants, the following trend was observed: roots > leaves > stems > berries. Copyright 2009 John Wiley & Sons, Ltd.

  6. Mineralogy and instrumental neutron activation analysis of seven National Bureau of Standards and three Instituto de Pesquisas Tecnologicas clay reference samples

    USGS Publications Warehouse

    Hosterman, John W.; Flanagan, F.J.; Bragg, Anne; Doughten, M.W.; Filby, R.H.; Grimm, Catherine; Mee, J.S.; Potts, P.J.; Rogers, N.W.

    1987-01-01

    The concentrations of 3 oxides and 29 elements in 7 National Bureau of Standards (NBS) and 3 Instituto de Pesquisas Techno16gicas (IPT) reference clay samples were etermined by instrumental neutron activation analysis. The analytical work was designed to test the homogeneity of constituents in three new NBS reference clays, NBS-97b, NBS-98b, and NBS-679. The analyses of variance of 276 sets of data for these three standards show that the constituents are distributed homogeneously among bottles of samples for 94 percent of the sets of data. Three of the reference samples (NBS-97, NBS-97a, and NBS-97b) are flint clays; four of the samples (NBS-98, NBS-98a, NBS-98b, and IPT-32) are plastic clays, and three of the samples (NBS-679, IPT-28, and IPT-42) are miscellaneous clays (both sedimentary and residual). Seven clays are predominantly kaolinite; the other three clays contain illite and kaolinite in the approximate ratio 3:2. Seven clays contain quartz as the major nonclay mineral. The mineralogy of the flint and plastic clays from Missouri (NBS-97a and NBS-98a) differs markedly from that of the flint and plastic clays from Pennsylvania (NBS-97, NBS-97b, NBS-98, and NBS-98b). The flint clay NBS-97 has higher average chromium, hafnium, lithium, and zirconium contents than its replacement, reference sample NBS-97b. The differences between the plastic clay NBS-98 and its replacement, NBS-98b, are not as pronounced. The trace element contents of the flint and plastic clays from Missouri, NBS-97a and NBS-98a, differ significantly from those of the clays from Pennsylvania, especially the average rare earth element (REE) contents. The trace element contents of clay sample IPT-32 differ from those of the other plastic clays. IPT-28 and IPT-42 have some average trace element contents that differ not only between these two samples but also from all the other clays. IPT-28 has the highest summation of the average REE contents of the 10 samples. The uranium content of NBS-98a, 46 parts per million, is very much higher than that of the other clays. Plots of average REE contents of the flint and plastic clays, normalized to chondritic abundances, show that the clays from Missouri differ from the same types of clay from Pennsylvania. The plot of REE contents for the miscellaneous clays shows that the normalized means for the elements lanthanum through samarium for IPT-28 are much greater than those for the other miscellaneous clays. The means for the elements europium through lutetium are similar for all three miscellaneous clays.

  7. Baseline Geochemical Data for Medical Researchers in Kentucky

    NASA Astrophysics Data System (ADS)

    Anderson, W.

    2017-12-01

    According to the Centers for Disease Control, Kentucky has the highest cancer incidence and death rates in the country. New efforts by geochemists and medical researchers are examining ways to diagnose the origin and sources of carcinogenesis. In an effort to determine if naturally occurring geochemical or mineral elements contributes to the cancer causation, the Kentucky Geological Survey has established a Minerals and Geochemical Database that is available to medical researchers for examination of baseline geochemistry and determine if naturally occurring mineral or chemical elements contribute to the high rate of cancers in the state. Cancer causation is complex, so if natural sources can be accounted for, then researchers can focus on the true causation. Naturally occurring minerals, metals and elements occur in many parts of the state, and their presence is valuable for evaluating causation. For example, some data in the database contain maps showing (a) statewide elemental geochemistry, (b) areas of black shale oxidation occurrence, which releases metals in soil and surface waters, (c) some clay deposits in the state that can contain high content of rare earth elements, and (d) site-specific uranium occurrences. Knowing the locations of major ore deposits in the state can also provide information related to mineral and chemical anomalies, such as for base metals and mercury. Radionuclide data in soil and water analyses are limited, so future research may involve obtaining more analyses to determine radon potential. This database also contains information on faulting and geology in the state. Although the metals content of trees may not seem relevant, the ash and humus content of degraded trees affects soil, stream sediment and water geochemistry. Many rural homes heat with wood, releasing metals into the surrounding biosphere. Stressed vegetation techniques can be used to explore for ore deposits and look for high metal contents in soils and rocks. These naturally occurring elements could be used for baseline information related to new collaborative research that integrates medicine, geology, forestry, and botany to predict metal contents of stream sediments, soil residuum, trees, plants, and forest cover and determine their relation to carcinogenesis.

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

    USGS Publications Warehouse

    Birdwell, Justin E.

    2012-01-01

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

  9. Partitioning experiments in the laser-heated diamond anvil cell: volatile content in the Earth's core.

    PubMed

    Jephcoat, Andrew P; Bouhifd, M Ali; Porcelli, Don

    2008-11-28

    The present state of the Earth evolved from energetic events that were determined early in the history of the Solar System. A key process in reconciling this state and the observable mantle composition with models of the original formation relies on understanding the planetary processing that has taken place over the past 4.5Ga. Planetary size plays a key role and ultimately determines the pressure and temperature conditions at which the materials of the early solar nebular segregated. We summarize recent developments with the laser-heated diamond anvil cell that have made possible extension of the conventional pressure limit for partitioning experiments as well as the study of volatile trace elements. In particular, we discuss liquid-liquid, metal-silicate (M-Sil) partitioning results for several elements in a synthetic chondritic mixture, spanning a wide range of atomic number-helium to iodine. We examine the role of the core as a possible host of both siderophile and trace elements and the implications that early segregation processes at deep magma ocean conditions have for current mantle signatures, both compositional and isotopic. The results provide some of the first experimental evidence that the core is the obvious replacement for the long-sought, deep mantle reservoir. If so, they also indicate the need to understand the detailed nature and scale of core-mantle exchange processes, from atomic to macroscopic, throughout the age of the Earth to the present day.

  10. Deep-sea mud in the Pacific Ocean as a potential resource for rare-earth elements

    NASA Astrophysics Data System (ADS)

    Kato, Yasuhiro; Fujinaga, Koichiro; Nakamura, Kentaro; Takaya, Yutaro; Kitamura, Kenichi; Ohta, Junichiro; Toda, Ryuichi; Nakashima, Takuya; Iwamori, Hikaru

    2011-08-01

    World demand for rare-earth elements and the metal yttrium--which are crucial for novel electronic equipment and green-energy technologies--is increasing rapidly. Several types of seafloor sediment harbour high concentrations of these elements. However, seafloor sediments have not been regarded as a rare-earth element and yttrium resource, because data on the spatial distribution of these deposits are insufficient. Here, we report measurements of the elemental composition of over 2,000 seafloor sediments, sampled at depth intervals of around one metre, at 78 sites that cover a large part of the Pacific Ocean. We show that deep-sea mud contains high concentrations of rare-earth elements and yttrium at numerous sites throughout the eastern South and central North Pacific. We estimate that an area of just one square kilometre, surrounding one of the sampling sites, could provide one-fifth of the current annual world consumption of these elements. Uptake of rare-earth elements and yttrium by mineral phases such as hydrothermal iron-oxyhydroxides and phillipsite seems to be responsible for their high concentration. We show that rare-earth elements and yttrium are readily recovered from the mud by simple acid leaching, and suggest that deep-sea mud constitutes a highly promising huge resource for these elements.

  11. The effect of cerium (III) on the chlorophyll formation in spinach.

    PubMed

    Fashui, Hong; Ling, Wang; Xiangxuan, Meng; Zheng, Wei; Guiwen, Zhao

    2002-12-01

    The effect of Ce(3+) on the chlorophyll (chl) of spinach was studied in pot culture experiments. The results showed that Ce(3+) could obviously stimulate the growth of spinach and increase its chlorophyll contents and photosynthetic rate. It could also improve the PSII formation and enhance its electron transport rate of PSII as well. By inductively coupled plasma-mass spectroscopy and atom absorption spectroscopy methods, it was revealed that the rare-earth-element (REE) distribution pattern in the Ce(3+)-treated spinach was leaf > root > shoot in Ce(3+) contents. The spinach leaves easily absorbed REEs. The Ce(3+) contents of chloroplast and chlorophyll of the Ce(3+)-treated spinach were higher than that of any other rare earth and were much higher than that of the control; it was also suggested that Ce(3+) could enter the chloroplast and bind easily to chlorophyll and might replace magnesium to form Ce-chlorophyll. By ultraviolet-visible, Fourier transform infrared, and extended X-ray absorption fine structure (EXAFS) methods, Ce(3+)-coordinated nitrogen of porphyrin rings with eight coordination numbers and average length of the Ce-N bond of 0.251 nm.

  12. GEOCAB Portal: A gateway for discovering and accessing capacity building resources in Earth Observation

    NASA Astrophysics Data System (ADS)

    Desconnets, Jean-Christophe; Giuliani, Gregory; Guigoz, Yaniss; Lacroix, Pierre; Mlisa, Andiswa; Noort, Mark; Ray, Nicolas; Searby, Nancy D.

    2017-02-01

    The discovery of and access to capacity building resources are often essential to conduct environmental projects based on Earth Observation (EO) resources, whether they are Earth Observation products, methodological tools, techniques, organizations that impart training in these techniques or even projects that have shown practical achievements. Recognizing this opportunity and need, the European Commission through two FP7 projects jointly with the Group on Earth Observations (GEO) teamed up with the Committee on Earth observation Satellites (CEOS). The Global Earth Observation CApacity Building (GEOCAB) portal aims at compiling all current capacity building efforts on the use of EO data for societal benefits into an easily updateable and user-friendly portal. GEOCAB offers a faceted search to improve user discovery experience with a fully interactive world map with all inventoried projects and activities. This paper focuses on the conceptual framework used to implement the underlying platform. An ISO19115 metadata model associated with a terminological repository are the core elements that provide a semantic search application and an interoperable discovery service. The organization and the contribution of different user communities to ensure the management and the update of the content of GEOCAB are addressed.

  13. Composition of the core from gallium metal–silicate partitioning experiments

    DOE PAGES

    Blanchard, I.; Badro, J.; Siebert, J.; ...

    2015-07-24

    We present gallium concentration (normalized to CI chondrites) in the mantle is at the same level as that of lithophile elements with similar volatility, implying that there must be little to no gallium in Earth's core. Metal-silicate partitioning experiments, however, have shown that gallium is a moderately siderophile element and should be therefore depleted in the mantle by core formation. Moreover, gallium concentrations in the mantle (4 ppm) are too high to be only brought by the late veneer; and neither pressure, nor temperature, nor silicate composition has a large enough effect on gallium partitioning to make it lithophile. Wemore » therefore systematically investigated the effect of core composition (light element content) on the partitioning of gallium by carrying out metal–silicate partitioning experiments in a piston–cylinder press at 2 GPa between 1673 K and 2073 K. Four light elements (Si, O, S, C) were considered, and their effect was found to be sufficiently strong to make gallium lithophile. The partitioning of gallium was then modeled and parameterized as a function of pressure, temperature, redox and core composition. A continuous core formation model was used to track the evolution of gallium partitioning during core formation, for various magma ocean depths, geotherms, core light element contents, and magma ocean composition (redox) during accretion. The only model for which the final gallium concentration in the silicate Earth matched the observed value is the one involving a light-element rich core equilibrating in a FeO-rich deep magma ocean (>1300 km) with a final pressure of at least 50 GPa. More specifically, the incorporation of S and C in the core provided successful models only for concentrations that lie far beyond their allowable cosmochemical or geophysical limits, whereas realistic O and Si amounts (less than 5 wt.%) in the core provided successful models for magma oceans deeper that 1300 km. In conclusion, these results offer a strong argument for an O- and Si-rich core, formed in a deep terrestrial magma ocean, along with oxidizing conditions.« less

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

    NASA Technical Reports Server (NTRS)

    Schwandt, Craig S.; McKay, Gordon A.

    1997-01-01

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

  15. Effect of the addition of low rare earth elements (lanthanum, neodymium, cerium) on the biodegradation and biocompatibility of magnesium.

    PubMed

    Willbold, Elmar; Gu, Xuenan; Albert, Devon; Kalla, Katharina; Bobe, Katharina; Brauneis, Maria; Janning, Carla; Nellesen, Jens; Czayka, Wolfgang; Tillmann, Wolfgang; Zheng, Yufeng; Witte, Frank

    2015-01-01

    Rare earth elements are promising alloying element candidates for magnesium alloys used as biodegradable devices in biomedical applications. Rare earth elements have significant effects on the high temperature strength as well as the creep resistance of alloys and they improve magnesium corrosion resistance. We focused on lanthanum, neodymium and cerium to produce magnesium alloys with commonly used rare earth element concentrations. We showed that low concentrations of rare earth elements do not promote bone growth inside a 750 μm broad area around the implant. However, increased bone growth was observed at a greater distance from the degrading alloys. Clinically and histologically, the alloys and their corrosion products caused no systematic or local cytotoxicological effects. Using microtomography and in vitro experiments, we could show that the magnesium-rare earth element alloys showed low corrosion rates, both in in vitro and in vivo. The lanthanum- and cerium-containing alloys degraded at comparable rates, whereas the neodymium-containing alloy showed the lowest corrosion rates. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Preliminary geochemical results of corals from the Puerto Morelos Reef, Southeastern Mexico

    NASA Astrophysics Data System (ADS)

    Marquez, N.; Kasper, J.

    2012-04-01

    A microprobe (MB), major, trace and rare earth elements (REE) analyses were carried out in three coral species Acropora palmata, Acropora cervicornis and Gorgonia ventalina at Puerto Morelos, Reef, Southeastern Mexico. This was done to assess the degree in which the corals developed under the different chemical-physical natural and artificial conditions. The corals were cut at the top and middle and based upon the observations by using the MB analysis, results showed the highest concentrations of Ag, Cu, Cr, Ni, S, Sr, Zn y Zr in Gorgonia Ventalina suggesting an impact coming from the industrial discharges and/or rusting of boats in the area. The results of X-ray fluorescence analysis for major and trace elements showed that the Fe , Sr and Zr increase their content in the skeletons of Acropora palmata y Gorgonia ventalina also asociated with the presence of human activity since the area is composed mainly by carbonate source sediments. The rare earth elements (REE) analysis showed that the negative anomaly of Ce suggests a well oxygenated, highly oxidative modern shallow waters, and high nutrients related to suspended matter for Acropora Palmata, Acropora cervicornis y Gorgonia ventalina, The Positive Eu anomaly in the corals are due to the development of the reef linked to the concentration of waters enriched in La. The Nd/Yb ratio indicates a shallow water development for the corals. This is also supported by the Ce/Ce* vs. Pr/Pr* ratios that indicate shallow marine waters in the development of the three corals studied (Ce*= 0.5La+0.5Pr and Pr*= 0.5Ce+0.5Nd). Enrichment of heavy rare earth elements (Gd-Lu) in the corals may be associated with high pH values and CO, OH- ions in the sea water.

  17. Influence of Dy in solid solution on the degradation behavior of binary Mg-Dy alloys in cell culture medium.

    PubMed

    Yang, Lei; Ma, Liangong; Huang, Yuanding; Feyerabend, Frank; Blawert, Carsten; Höche, Daniel; Willumeit-Römer, Regine; Zhang, Erlin; Kainer, Karl Ulrich; Hort, Norbert

    2017-06-01

    Rare earth element Dy is one of the promising alloying elements for magnesium alloy as biodegradable implants. To understand the effect of Dy in solid solution on the degradation of Mg-Dy alloys in simulated physiological conditions, the present work studied the microstructure and degradation behavior of Mg-Dy alloys in cell culture medium. It is found the corrosion resistance enhances with the increase of Dy content in solid solution in Mg. This can be attributed to the formation of a relatively more corrosion resistant Dy-enriched film which decreases the anodic dissolution of Mg. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Sulfur in Earth's Mantle and Its Behavior During Core Formation

    NASA Technical Reports Server (NTRS)

    Chabot, Nancy L.; Righter,Kevin

    2006-01-01

    The density of Earth's outer core requires that about 5-10% of the outer core be composed of elements lighter than Fe-Ni; proposed choices for the "light element" component of Earth's core include H, C, O, Si, S, and combinations of these elements [e.g. 1]. Though samples of Earth's core are not available, mantle samples contain elemental signatures left behind from the formation of Earth's core. The abundances of siderophile (metal-loving) elements in Earth's mantle have been used to gain insight into the early accretion and differentiation history of Earth, the process by which the core and mantle formed, and the composition of the core [e.g. 2-4]. Similarly, the abundance of potential light elements in Earth's mantle could also provide constraints on Earth's evolution and core composition. The S abundance in Earth's mantle is 250 ( 50) ppm [5]. It has been suggested that 250 ppm S is too high to be due to equilibrium core formation in a high pressure, high temperature magma ocean on early Earth and that the addition of S to the mantle from the subsequent accretion of a late veneer is consequently required [6]. However, this earlier work of Li and Agee [6] did not parameterize the metalsilicate partitioning behavior of S as a function of thermodynamic variables, limiting the different pressure and temperature conditions during core formation that could be explored. Here, the question of explaining the mantle abundance of S is revisited, through parameterizing existing metal-silicate partitioning data for S and applying the parameterization to core formation in Earth.

  19. How PNNL Extracts Rare Earth Elements from Geothermal Brine

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None

    2016-07-12

    By looking at a problem at a nanoscale level, PNNL researchers are developing an economic way to extract valuable rare earth elements from geothermal fluids. This novel approach may help meet the high demand for rare earth elements that are used in many clean energy technologies.

  20. Geochemistry of Thorium and Uranium in Soils of the Southern Urals

    NASA Astrophysics Data System (ADS)

    Asylbaev, I. G.; Khabirov, I. K.; Gabbasova, I. M.; Rafikov, B. V.; Lukmanov, N. A.

    2017-12-01

    Specific features of the horizontal and vertical distribution of uranium and thorium in soils and parent materials of the Southern Urals within the Bashkortostan Republic have been studied with the use of mass spectrometry with inductively coupled plasma. The dependence of distribution patterns of these elements on the local environmental conditions is shown. A scale for soil evaluation according to the concentrations of uranium and thorium (mg/kg) is suggested: the low level, up to 3; medium, up to 9; high, up to 15; and very high, above 15 mg/kg. On the basis of to this scale, the ecological state of the soils is evaluated, and the schematic geochemical map of the region is compiled. The territory of Bashkortostan is subdivided into two parts according to the contents of radioactive elements in soils: the western part with distinct accumulation of uranium and the eastern part with predominant thorium accumulation. This finding supports the charriage (thrust fault) nature of the fault zone of the Southern Urals. The vertical distribution patterns of uranium and thorium in soils of the region are of the same character. The dependence between the contents of these two elements and rare-earth elements has been established. The results of this study are applied for assessing the ecological state of soils in the region.

  1. Geochemistry of Archean shales from the Pilbara Supergroup, Western Australia

    NASA Astrophysics Data System (ADS)

    McLennan, Scott M.; Taylor, S. R.; Eriksson, K. A.

    1983-07-01

    Archean clastic sedimentary rocks are well exposed in the Pilbara Block of Western Australia. Shales from turbidites in the Gorge Creek Group ( ca. 3.4 Ae) and shales from the Whim Creek Group ( ca. 2.7 Ae) have been examined. The Gorge Creek Group samples, characterized by muscovite-quartzchlorite mineralogy, are enriched in incompatible elements (K, Th, U, LREE) by factors of about two, when compared to younger Archean shales from the Yilgarn Block. Alkali and alkaline earth elements are depleted in a systematic fashion, according to size, when compared with an estimate of Archean upper crust abundances. This depletion is less notable in the Whim Creek Group. Such a pattern indicates the source of these rocks underwent a rather severe episode of weathering. The Gorge Creek Group also has fairly high B content (85 ± 29 ppm) which may indicate normal marine conditions during deposition. Rare earth element (REE) patterns for the Pilbara samples are characterized by light REE enrichment ( La N/Yb N ≥ 7.5 ) and no or very slight Eu depletion ( Eu/Eu ∗ = 0.82 - 0.99 ). A source comprised of about 80% felsic igneous rocks without large negative Eu-anomalies (felsic volcanics, tonalites, trondhjemites) and 20% mafic-ultramafic volcanics is indicated by the trace element data. Very high abundances of Cr and Ni cannot be explained by any reasonable provenance model and a secondary enrichment process is called for.

  2. Magnesium Content of the Core: an Experimental Study

    NASA Astrophysics Data System (ADS)

    Fiquet, G.; Badro, J.; Auzende, A.; Siebert, J.; Gregoryanz, E.; Guignot, N.

    2006-12-01

    There is still a considerable debate about which light element among sulfur, silicon, oxygen, carbon or hydrogen should be in the core [Poirier, Phys. Earth Planet. Int., 85, 319, 1994]. The nature and distribution of these elements is a standing problem of prime importance, since it controls the freezing point depression at the inner core boundary. In addition to these candidates, new elements have been recently proposed as iron alloying constituants for the core, such as magnesium [Dubrovinskaia et al., Phys. Rev. Lett., 95, 245502, 2005]. We present series of experiments carried out on hot-pressed samples of iron and periclase in a laser-heated diamond-anvil cell, combined with in situ X-ray diffraction analysis and ATEM examination of recovered samples. We show that even at megabar pressures the amount of magnesium released in iron from the equilibrium with magnesium oxide is marginal. This finding is at odds with the 10 at% of magnesium found by Dubrovinskaia et al. [2005] in an iron alloy made from the reaction between iron and a metallic magnesium foil. Our observations suggest that magnesium is unlikely to be an important light element in the Earth's core. In addition, we provide structural data for iron to 130 GPa in excess of 3000 K with reliable pressure and temperature measurements, which enable us to propose a new thermal equation of state for iron at megabar pressures.

  3. The redox state of the mantle during and just after core formation.

    PubMed

    Frost, D J; Mann, U; Asahara, Y; Rubie, D C

    2008-11-28

    Siderophile elements are depleted in the Earth's mantle, relative to chondritic meteorites, as a result of equilibration with core-forming Fe-rich metal. Measurements of metal-silicate partition coefficients show that mantle depletions of slightly siderophile elements (e.g. Cr, V) must have occurred at more reducing conditions than those inferred from the current mantle FeO content. This implies that the oxidation state (i.e. FeO content) of the mantle increased with time as accretion proceeded. The oxygen fugacity of the present-day upper mantle is several orders of magnitude higher than the level imposed by equilibrium with core-forming Fe metal. This results from an increase in the Fe2O3 content of the mantle that probably occurred in the first 1Ga of the Earth's history. Here we explore fractionation mechanisms that could have caused mantle FeO and Fe2O3 contents to increase while the oxidation state of accreting material remained constant (homogeneous accretion). Using measured metal-silicate partition coefficients for O and Si, we have modelled core-mantle equilibration in a magma ocean that became progressively deeper as accretion proceeded. The model indicates that the mantle would have become gradually oxidized as a result of Si entering the core. However, the increase in mantle FeO content and oxygen fugacity is limited by the fact that O also partitions into the core at high temperatures, which lowers the FeO content of the mantle. (Mg,Fe)(Al,Si)O3 perovskite, the dominant lower mantle mineral, has a strong affinity for Fe2O3 even in the presence of metallic Fe. As the upper mantle would have been poor in Fe2O3 during core formation, FeO would have disproportionated to produce Fe2O3 (in perovskite) and Fe metal. Loss of some disproportionated Fe metal to the core would have enriched the remaining mantle in Fe2O3 and, if the entire mantle was then homogenized, the oxygen fugacity of the upper mantle would have been raised to its present-day level.

  4. Innovative Approaches to Remote Sensing in NASA's Earth System Science Pathfinder (ESSP) Program

    NASA Technical Reports Server (NTRS)

    Peri, Frank; Volz, Stephen

    2013-01-01

    NASA's Earth Venture class (EV) of mission are competitively selected, Principal Investigator (PI) led, relatively low cost and narrowly focused in scientific scope. Investigations address a full spectrum of earth science objectives, including studies of the atmosphere, oceans, land surface, polar ice regions, and solid Earth. EV has three program elements: EV-Suborbital (EVS) are suborbital/airborne investigations; EV-Mission (EVM) element comprises small complete spaceborne missions; and EV-Instrument (EVI) element develops spaceborne instruments for flight as missions-of-opportunity (MoO). To ensure the success of EV, the management approach of each element is tailored according to the specific needs of the element.

  5. Opportunities for Small Satellites in NASA's Earth System Science Pathfinder (ESSP) Program

    NASA Technical Reports Server (NTRS)

    Peri, Frank; Law, Richard C.; Wells, James E.

    2014-01-01

    NASA's Earth Venture class (EV) of missions are competitively selected, Principal Investigator (PI) led, relatively low cost and narrowly focused in scientific scope. Investigations address a full spectrum of earth science objectives, including studies of the atmosphere, oceans, land surface, polar ice regions, and solid Earth. EV has three program elements: EV-Suborbital (EVS) are suborbital/airborne investigations; EV-Mission (EVM) element comprises small complete spaceborne missions; and EV-Instrument (EVI) element develops spaceborne instruments for flight as Missions-of-Opportunity (MoO). To ensure the success of EV, frequent opportunities for selecting missions has been established in NASA's Earth Science budget. This paper will describe those opportunities and how the management approach of each element is tailored according to the specific needs of the element.

  6. Geochemistry of Rock Samples Collected from the Iron Hill Carbonatite Complex, Gunnison County, Colorado

    USGS Publications Warehouse

    Van Gosen, Bradley S.

    2008-01-01

    A study conducted in 2006 by the U.S. Geological Survey collected 57 surface rock samples from nine types of intrusive rock in the Iron Hill carbonatite complex. This intrusive complex, located in Gunnison County of southwestern Colorado, is known for its classic carbonatite-alkaline igneous geology and petrology. The Iron Hill complex is also noteworthy for its diverse mineral resources, including enrichments in titanium, rare earth elements, thorium, niobium (columbium), and vanadium. This study was performed to reexamine the chemistry and metallic content of the major rock units of the Iron Hill complex by using modern analytical techniques, while providing a broader suite of elements than the earlier published studies. The report contains the geochemical analyses of the samples in tabular and digital spreadsheet format, providing the analytical results for 55 major and trace elements.

  7. Chelating resin immobilizing carboxymethylated polyethyleneimine for selective solid-phase extraction of trace elements: Effect of the molecular weight of polyethyleneimine and its carboxymethylation rate.

    PubMed

    Kagaya, Shigehiro; Kajiwara, Takehiro; Gemmei-Ide, Makoto; Kamichatani, Waka; Inoue, Yoshinori

    2016-01-15

    The effect of the molecular weight of polyethyleneimine (PEI), defined as a compound having two or more ethyleneamine units, and of its carboxymethylation rate (CM/N), represented by the ratio of ion-exchange capacity to the amount of N on the resin, on the selective solid-phase extraction ability of the chelating resin immobilizing carboxymethylated (CM) PEI was investigated. The chelating resins (24 types) were prepared by immobilization of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, PEI300 (MW=ca. 300), and PEI600 (MW=ca. 600) on methacrylate resins, followed by carboxymethylation with various amounts of sodium monochloroacetate. When resins with approximately the same CM/N ratio (0.242-0.271) were used, the recovery of Cd, Co, Cu, Fe, Ni, Pb, Ti, Zn, and alkaline earth elements increased with increasing the molecular weight of PEIs under acidic and weakly acidic conditions; however, the extraction behavior of Mo and V was only slightly affected. This was probably due to the increase in N content of the resin, resulting in an increase in carboxylic acid groups; the difference in the molecular weight of PEIs immobilized on the resin exerts an insignificant influence on the selective extraction ability. The CM/N ratio considerably affected the extraction behavior for various elements. Under acidic and neutral conditions, the recovery of Cd, Co, Cu, Fe, Ni, Pb, Ti, and Zn increased with increasing CM/N values. However, under these conditions, the recovery of alkaline earth elements was considerably low when a resin with low CM/N ratio was used. This is presumably attributed to the different stability constants of the complexes of these elements with aminocarboxylic acids and amines, and to the electrostatic repulsion between the elements and the protonated amino groups in the CM-PEI. The recovery of Mo and V decreased or varied with increasing CM/N values, suggesting that the extraction of these elements occurred mainly by the anion-exchange reaction. For the separation and preconcentration of trace elements in samples containing large amounts of alkali and alkaline earth elements, the CM-PEI600 resin with CM/N=0.131 (Cu(II) extraction capacity, 0.37mmol g(-)(1)) was found to be the most suitable because it scarcely extracts alkali and alkaline earth elements under acidic and neutral conditions. This resin proved to be convenient for separating and preconcentrating Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, V, and Zn in the certified reference materials (EnviroMAT EU-L-1 wastewater and ES-L-1 ground water) and commercially available table salt. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    USGS Publications Warehouse

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

    1955-01-01

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

  9. Thermal Diffusion Fractionation of Cr and V Isotope in Silicate Melt

    NASA Astrophysics Data System (ADS)

    Lin, X.; Lundstrom, C.

    2017-12-01

    Earth's mantle is isotopically heavy relative to chondrites for V, Cr and some other siderophile elements. A possible solution is that isotopic fractionation by thermal diffusion occurs in a thermal boundary layer between solid mantle and an underlying basal magma ocean (BMO:Labrosse et al.,2007). If so, isotopically light composition might partition into the core, resulting in a complimentary isotopically heavy solid mantle. To verify how much fractionation could happen in this process, piston cylinder experiment were conducted to investigate the fractionation of Cr and V isotope ratios in partially molten silicate under an imposed temperature gradient from 1650 °C to 1350 °C at 1 GPa for 10 to 50 hours to reach a steady state isotopic profile. The temperature profile for experiments was determined by the spinel-growth method at the same pressure and temperature. Experimental runs result in 100% glass at the hot end progressing to nearly 100 % olivine at the cold end. Major and minor element concentrations of run products show systematic changes with temperature. Glass MgO contents increase and Al2O3 and CaO contents decrease by several weight percent as temperature increases across the charge. These are well modeled using IRIDIUM (Boudreau 2003) to simulate the experiments. Isotopic composition measurements of Cr and V at different temperatures are in progress, providing the first determinations of thermal diffusion isotopic sensitivity, Ω (permil isotopic fractionation per temperature offset per mass unit) for these elements. These results will be compared with previously determined Ω for network formers and modifiers and used in a BMO-based thermal diffusion model for formation of Earth's isotopically heavy mantle.

  10. Facile Arsenazo III-Based Assay for Monitoring Rare Earth Element Depletion from Cultivation Media for Methanotrophic and Methylotrophic Bacteria

    PubMed Central

    Hogendoorn, Carmen; Roszczenko-Jasińska, Paula; Martinez-Gomez, N. Cecilia; de Graaff, Johann; Grassl, Patrick; Pol, Arjan; Op den Camp, Huub J. M.

    2018-01-01

    ABSTRACT Recently, methanotrophic and methylotrophic bacteria were found to utilize rare earth elements (REEs). To monitor the REE content in culture media of these bacteria, we have developed a rapid screening method using the Arsenazo III (AS III) dye for spectrophotometric REE detection in the low μM (0.1 to 10 μM) range. We designed this assay to follow LaIII and EuIII depletion from the culture medium by the acidophilic verrucomicrobial methanotroph Methylacidiphilum fumariolicum strain SolV. The assay can also be modified to screen the uptake of other REEs, such as PrIII, or to monitor the depletion of LaIII from growth media in neutrophilic methylotrophs such as Methylobacterium extorquens strain AM1. The AS III assay presents a convenient and fast detection method for REE levels in culture media and is a sensitive alternative to inductively coupled plasma mass spectrometry (ICP-MS) or atomic absorption spectroscopy (AAS). IMPORTANCE REE-dependent bacterial metabolism is a quickly emerging field, and while the importance of REEs for both methanotrophic and methylotrophic bacteria is now firmly established, many important questions, such as how these insoluble elements are taken up into cells, are still unanswered. Here, an Arsenazo III dye-based assay has been developed for fast, specific, and sensitive determination of REE content in different culture media. This assay presents a useful tool for optimizing cultivation protocols, as well as for routine REE monitoring during bacterial growth without the need for specialized analytical instrumentation. Furthermore, this assay has the potential to promote the discovery of other REE-dependent microorganisms and can help to elucidate the mechanisms for acquisition of REEs by methanotrophic and methylotrophic bacteria. PMID:29453257

  11. Facile Arsenazo III-Based Assay for Monitoring Rare Earth Element Depletion from Cultivation Media for Methanotrophic and Methylotrophic Bacteria.

    PubMed

    Hogendoorn, Carmen; Roszczenko-Jasińska, Paula; Martinez-Gomez, N Cecilia; de Graaff, Johann; Grassl, Patrick; Pol, Arjan; Op den Camp, Huub J M; Daumann, Lena J

    2018-04-15

    Recently, methanotrophic and methylotrophic bacteria were found to utilize rare earth elements (REEs). To monitor the REE content in culture media of these bacteria, we have developed a rapid screening method using the Arsenazo III (AS III) dye for spectrophotometric REE detection in the low μM (0.1 to 10 μM) range. We designed this assay to follow La III and Eu III depletion from the culture medium by the acidophilic verrucomicrobial methanotroph Methylacidiphilum fumariolicum strain SolV. The assay can also be modified to screen the uptake of other REEs, such as Pr III , or to monitor the depletion of La III from growth media in neutrophilic methylotrophs such as Methylobacterium extorquens strain AM1. The AS III assay presents a convenient and fast detection method for REE levels in culture media and is a sensitive alternative to inductively coupled plasma mass spectrometry (ICP-MS) or atomic absorption spectroscopy (AAS). IMPORTANCE REE-dependent bacterial metabolism is a quickly emerging field, and while the importance of REEs for both methanotrophic and methylotrophic bacteria is now firmly established, many important questions, such as how these insoluble elements are taken up into cells, are still unanswered. Here, an Arsenazo III dye-based assay has been developed for fast, specific, and sensitive determination of REE content in different culture media. This assay presents a useful tool for optimizing cultivation protocols, as well as for routine REE monitoring during bacterial growth without the need for specialized analytical instrumentation. Furthermore, this assay has the potential to promote the discovery of other REE-dependent microorganisms and can help to elucidate the mechanisms for acquisition of REEs by methanotrophic and methylotrophic bacteria. Copyright © 2018 Hogendoorn et al.

  12. Determination of rare earth elements in environmental matrices by sector-field inductively coupled plasma mass spectrometry.

    PubMed

    Riondato, J; Vanhaecke, F; Moens, L; Dams, R

    2001-07-01

    In the framework of an international certification campaign, sector-field inductively coupled plasma mass spectrometry (sector-field ICP-MS) was used for the accurate determination of the rare earth elements in five candidate reference materials: aquatic plant, calcareous soil, mussel tissue, river sediment, and tuna muscle. All samples were taken into solution by use of microwave-assisted or mixed microwave-assisted / open beaker acid digestion. Subsequently, the samples were appropriately diluted and subjected to ICP-MS analysis. Except for Sc, all the elements involved were determined at low mass resolution (R = 300). For Sc, application of a higher resolution setting (R = 3,000) was required to separate the analyte signal from those of several molecular ions which gave rise to spectral overlap at low mass resolution. Some of the heavier REE can also suffer from spectral overlap attributed to the occurrence of oxide ions (MO+) of the lighter REE and Ba. This spectral overlap could be successfully overcome by mathematical correction. Matrix effects were overcome by use of two carefully selected internal standards, such that external calibration could be used. On each occasion, a geological reference material was analyzed as a quality-control sample and the reliability of all results obtained was additionally checked by means of chondrite normalization. For tuna muscle the content of all REE was below the limit of detection. For calcareous soil and river sediment, low to sub microg g(-1) values were observed, whereas the REE content of aquatic plant and mussel tissue was considerably lower (low to sub ng g(-1)). Overall, the results obtained were in excellent agreement with the average values, calculated on the basis of all "accepted" values, obtained in different laboratories using different techniques.

  13. The behavior of osmium and other siderophile elements during impacts: Insights from the Ries impact structure and central European tektites

    NASA Astrophysics Data System (ADS)

    Ackerman, Lukáš; Magna, Tomáš; Žák, Karel; Skála, Roman; Jonášová, Šárka; Mizera, Jiří; Řanda, Zdeněk

    2017-08-01

    Impact processes are natural phenomena that contribute to a variety of physico-chemical mechanisms over an extreme range of shock pressures and temperatures, otherwise seldomly achieved in the Earth's crust through other processes. Under these extreme conditions with transient temperatures and pressures ≥3000 K and ≥100 GPa, followed by their rapid decrease, the behavior of elements has remained poorly understood. Distal glassy ejecta (tektites) were produced in early phases of contact between the Earth's surface and an impacting body. Here we provide evidence for a complex behavior of Os and other highly siderophile elements (HSE; Ir, Ru, Pt, Pd, and Re) during tektite production related to a hyper-velocity impact that formed the Ries structure in Germany. Instead of simple mixing between the surface materials, which are thought to form the major source of central European tektites (moldavites), and impactor matter, the patterns of HSE contents and 187Re/188Os - 187Os/188Os ratios in moldavites, target sediments and impact-related breccias (suevites) can be explained by several sequential and/or contemporary processes. These involve (i) evaporative loss of partially oxidized HSE from the overheated tektite melt, (ii) mixing of target-derived and impactor-derived HSE vapor (plasma) phases, and (iii) early (high-temperature) condensation of a part of the mixed vapor phase back to silicate melt droplets. An almost complete loss of terrestrial Os from the tektite melt and its replacement with extra-terrestrial Os are indicated by low 187Os/188Os ratios in tektites (<0.163) relative to precursor materials (>0.69). This is paralleled by a co-variation between Os and Ni contents in tektites but not in suevites formed later in the impact process.

  14. Studies on the content of heavy metals in Aries River using ICP-MS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Voica, Cezara, E-mail: Cezara.Voica@itim-cj.ro; Kovacs, Melinda, E-mail: Cezara.Voica@itim-cj.ro; Feher, Ioana, E-mail: Cezara.Voica@itim-cj.ro

    2013-11-13

    Among the industrial branches, the mining industry has always been an important source of environmental pollution, both aesthetically and chemically. Through this paper results of ICP-MS characterization of Aries River Basin are reported. Mining activities from this area has resulted in contamination of environment and its surrounding biota. This is clearly evidenced in analyzed water samples, especially from Baia de Aries site where increased amount of trace elements as Cr, Zn, As, Se, Cd, Pb and U were founded. Also in this site greater amount of rare earth elements was evidenced also. Through monitoring of Aries River from other non-miningmore » area it was observed that the quantitative content of heavy metals was below the maximum permissible levels which made us to conclude that the water table wasn't seriously affected (which possibly might be attributed to the cessation of mining activities in this area from a few years ago)« less

  15. Map of Martian Potassium at Mid-Latitudes

    NASA Image and Video Library

    2003-03-13

    This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element potassium. Potassium, having the chemical symbol K, is a naturally radioactive element and is a minor constituent of rocks on the surface of both Mars and Earth. The region of highest potassium content, shown in red, is concentrated in the northern part of Acidalia Planitia (centered near 55 degrees N, -30 degrees). Several areas of low potassium content, shown in blue, are distributed across the mid-latitudes, with two significant low concentrations, one associated with the Hellas Basin (centered near 35 degrees S, 70 degrees) and the other lying southeast of Elysium Mons (centered near 10 degrees N, 160 degrees). Contours of constant surface elevation are also shown. The long continuous line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south. http://photojournal.jpl.nasa.gov/catalog/PIA04255

  16. Ordinary Stoichiometry of Extraordinary Microbes

    NASA Astrophysics Data System (ADS)

    Neveu, M.; Poret-Peterson, A. T.; Anbar, A. D.; Elser, J. J.

    2013-12-01

    Life on Earth seems to be composed of the same chemical elements in relatively conserved stoichiometric proportions. However, this observation is largely based on observations of biota from habitats spanning a moderate range of temperature and chemical composition (e.g., temperate lakes, forests, grasslands, oceanic phytoplankton). Whether this stoichiometry is conserved in settings that differ radically from such "normal" planetary settings may provide insight into the habitability of environments with radically different stoichiometries, and into possible stoichiometries for putative life beyond Earth. Here we report the first measurements of elemental stoichiometries of microbial extremophiles from hot springs of Yellowstone National Park (YNP). These phototrophic and chemotrophic microbes were collected in locations spanning large ranges of temperature (ambient to boiling) and pH (1 to 9). Microbial biomass was carefully extracted from hot spring sediment substrata following a procedure adapted from [1], which conserves cellular elemental abundances [2]. Their C and N contents were determined by Elemental Analysis Isotope Ratio Mass Spectrometry, and their P and trace element (Mg, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, and non-biogenic Al and Ti) contents were measured by Inductively Coupled Plasma Mass Spectrometry. Residual mineral contamination was an issue in some samples with low measured C and N; we eliminated these from our results. Even in the remaining samples, contamination sometimes prevented accurate determinations of cellular Mg, Ca, Mn, and Fe abundances; however, the cellular Ni, Cu, Zn, and Mo contents were several-fold above contamination level. Although hot spring water and sediment elemental abundances varied by orders of magnitude, the data showed that the extremophiles have a major and trace element stoichiometry similar to those previously measured in "normal" microbial biomass [3-6]. For example, biomass C:N:P ratios resembled those commonly observed in temperate lakes (e.g., C:P ratios of 260 to 1600 and N:P ratios of 35 to 200) while cellular C:Fe ratios were of a similar magnitude to those of marine phytoplankton. Exceptions were Al and Ti, much higher than previously measured, likely because of contamination from residual sediment. Moreover, the low phosphorus contents (high C:P and N:P ratios) are suggestive of limited P supply. Chemotrophs and phototrophs had similar elemental compositions to one another, although Mg, Mn, Ni, and Zn abundances were higher and nearly constant in phototrophs, due to their importance in phototrophic metabolism. Despite the tremendous physical and chemical diversity of YNP environments, the stoichiometry of life in these settings is surprisingly ordinary. Thus, our study supports the view that the biological stoichiometry of life is heavily constrained by the elemental composition of core biomolecules, and that even life in extreme environments must operate within these constraints. In the frame of life detection in exotic locales, these results suggest a general elemental biosignature for life as we know it. References: [1] Amalfitano and Fazi. 2008. J. Microbiol. Meth. 75:237 [2] Neveu et al. L&O: Meth., in review [3] Ho et al. 2003. J. Phycol. 39:1145 [4] Nuester et al. 2012. Front. Microbiol. 3:150 [5] Sterner and Elser. 2002. Ecological Stoichiometry. Princeton U. Press [6] Twining et al. 2011. Deep-Sea Res. II 58:325

  17. Geochronology and geochemistry of the Niujuanzi ophiolitic mélange, Gansu Province, NW China: implications for tectonic evolution of the Beishan Orogenic Collage

    NASA Astrophysics Data System (ADS)

    Wang, Shengdong; Zhang, Kexin; Song, Bowen; Li, Shucai; Li, Ming; Zhou, Jie

    2018-01-01

    The Niujuanzi ophiolitic mélange (NOM), located in the Beishan Orogenic Collage, marks the termination between the Huaniushan arc and Mingshui-Hanshan Massifs. The NOM is mainly composed of gabbros, diabases, plagiogranites, basalts, and greywacke. Two gabbros have ages of 433.8 ± 3.1 and 354.0 ± 3.3 Ma, two plagiogranites have ages of 429.8 ± 2 and 448.7 ± 2.0 Ma, and a diabase has an age of 433.4 ± 3.2 Ma. The gabbros and diabases are calc-alkaline and tholeiitic, with high Al2O3, CaO, and TiO2 contents and low FeOT contents. The gabbros have high Mg# values (49-82), while the diabases have relatively low Mg# values (46-61). The plagiogranites are calc-alkaline and metaluminous, with high SiO2 and Na2O contents and low Al2O3 and K2O contents. The gabbros and diabases are enriched in large iron lithophile elements and slightly depleted in high field strength elements relative to N-MORB and their trace element characteristics are similar to E-MORB. With respect to rare earth element (REE), they have slightly enriched LREEs relative to HREEs. The majority of the plagiogranite trace elements approximate those of the volcanic arc granite. The plagiogranites have obviously enriched LREEs relative to HREEs, with a slightly to strongly negative Eu anomaly, which is similar to ORG but distinct from volcanic arc and within plate granite. The NOM was formed from the Ordovician to the Carboniferous, representing the expansion period of the Niujuanzi Ocean. The gabbros, diabases, and plagiogranites were formed in a mid-ocean ridge environment. The gabbros and diabases were generated by different degrees of partial melting of the mantle, and the plagiogranites derived from both the crystallization differentiation of basaltic magma and the partial melting of amphibolites in the crust.

  18. Manufacturing of Dysprosium-Iron Alloys by Electrolysis in Fluoride-Based Electrolytes. Electrolysis in a Laboratory-Scale Cell

    NASA Astrophysics Data System (ADS)

    Martinez, Ana Maria; Osen, Karen Sende; Støre, Anne; Gudbrandsen, Henrik; Kjos, Ole Sigmund; Solheim, Asbjørn; Wang, Zhaohui; Oury, Alexandre; Namy, Patrick

    2018-04-01

    Electrolytic production of light rare earth elements and rare earth alloys with transition elements takes place in a fluoride-based electrolyte using rare earth oxides as raw material. The optimization of this method, mainly in terms of the energy efficiency and environmental impact control, is rather challenging. Anode effects, evolution of fluorine-containing compounds and side cathode reactions could largely be minimized by good control of the amount of rare earth oxide species dissolved in the fluoride-based electrolyte and their dissolution rate. The Dy2O3 feed rate needed for stable cell operation was studied by following up the anode voltage and gas analysis. On-line analysis of the cell off-gases by FTIR showed that the electrochemical reaction for the formation of Dy-Fe alloy gives mainly CO gas and that CF4 is starting to evolve gradually at anode voltages of ca. 3.25 V. The limiting current density for the discharge of the oxide ions at the graphite anode was in the range of 0.1 to 0.18 A cm-2 at dissolved Dy2O3 contents of ca. 1 wt pct. Modeling of the laboratory cell reactor was also carried out by implementing two models, i.e., an electrical model simulating the current density distribution at the electrodes and a laminal bubbly flow model that explains the electrolyte velocity induced by gas bubble production at the anode.

  19. Behaviour of elements in soils developed from nephelinites at Mount Etinde (Cameroon): Impact of hydrothermal versus weathering processes

    NASA Astrophysics Data System (ADS)

    Etame, J.; Gerard, M.; Bilong, P.; Suh, C. E.

    2009-05-01

    The progressive weathering of 0.65 Ma nephelinites from Mount Etinde (South Western Cameroon) in a humid tropical setting has resulted in the formation of a 150 cm thick weathering crust. The soil profiles consist of three horizons: Ah/Bw/C. A major differentiation of the chemical and mineralogical parameters is related to the complexity of the saprolites, some of which were hydrothermally altered. Bulk geochemical and microgeochemical analyses were performed on selected minerals from the different horizons of two reference profiles, of which one (E 4) was developed from unaltered nephelinite (nephelinite U) while the other (BO 1) formed from hydrothermally altered nephelinite (nephelinite H). The results show that the primary minerals (clinopyroxene, nepheline, leucite, haüyne, titanomagnetite, perovskite, apatite and sphene) experienced differential weathering rates with primary minerals rich in rare earth elements (titanomagnetite, perovskite, apatite and sphene) surviving in the saprolite and the Bw horizons. The weathering of the primary minerals is reflected in the leaching of alkaline and alkaline-earth elements, except for Ba and Rb in the hydrothermalised nephelinite soil. The order of mobility is influenced by hydrothermal processes: Na > K > Rb > Ca > Cs > Sr in nephelinite U soil , Na > K > Sr > Ca > Mg in nephelinite H soil; Rb/Sr and Sr/Mg can be used as indicators of the kinetic of the weathering on nephelinite U and on nephelinite H. Barium enrichment is related to variable concentrations in the nephelinites, to the formation of crandallites and the leaching of surface horizons. The content of metallic elements is higher in nephelinite H soil than in the nephelinite U soil. Results show that hydrothermal alteration leads to an enrichment of light (La, Ce, Nd) and intermediate (Sm, Eu, Dy) rare earth elements. The enrichment in Cr and Pb in the surface horizons is discussed in relation to organic matter activity, the dissolution of magnetites, and the impact of hydrothermal processes as well as atmospheric pollution in the case of lead.

  20. Geochemistry and mineralogy of Early Archean spherule beds, Baberton Mountain Land, South Africa: Evidence for origin by impact doubtful

    NASA Astrophysics Data System (ADS)

    Koeberl, Christian; Reimold, Wolf Uwe; Boer, Rudolf H.

    1993-09-01

    Spherule layers in the approximately 3.4 Ga Barberton Greenstone Belt, South Africa, have been interpreted as being the result of large asteroid or comet impacts on the early earth. This interpretation was based, among other arguments, on the enrichment of siderophile elements, especially the platinum group elements. We made a detailed mineralogical, petrological and geochemical study of spherule bed samples taken from drill cores and underground esposures at the Princeton, Mt. Morgan and Sheba gold mines, as well as surface localities. The macrostructure of each sample (from within different spherule layer units) shows evidence for multiple (more than five) events over about 30 cm. The mineralogy provides evidence for extensive hydrothermal and metasomatic alterations of the spherule beds. Geochemical analyses of alternating spherule, shale and chert layers show no correlation between the siderophile elements (e.g., Ir, Co, Ni and Au), contrary to that which would be expected if the siderophile elements had an extraterrestrial source. Furthermore, no significant variation in the content of the siderophile elements was detected between spherule layers and shale layers; however, siderophile element contents are high only in layers containing abundant sulphide minerals and having high As, Sb, Se and Cr contents. We suggest that complex mineralizations, similar to those that have formed the Barberton Archean gold deposits or the Bon Accord deposit, were responsible for the siderophile element enrichments in the spherule beds. Nowhere else in the world have such multiple (or even single) spherule beds been observed, and none of the numerous known impact craters (or the Cretaceous-Tertiary boundary) is associated with comparable spherule beds. Known impact debris usually contains less than 1% meteoritic component, if any at all, while Barberton spherules are anomalous in being extremely enriched compared to any known impact deposits.

  1. Rare earth elements and critical metal content of extracted landfilled material and potential recovery opportunities.

    PubMed

    Gutiérrez-Gutiérrez, Silvia C; Coulon, Frédéric; Jiang, Ying; Wagland, Stuart

    2015-08-01

    Rare earth elements (REEs), Platinum group metals (PGMs) and other critical metals currently attract significant interest due to the high risks of supply shortage and substantial impact on the economy. Their uses in many applications have made them present in municipal solid waste (MSW) and in commercial and industrial waste (C&I), since several industrial processes produce by-products with high content of these metals. With over 4000 landfills in the UK alone, the aim of this study was to assess the existence of these critical metals within landfills. Samples collected from four closed landfills in UK were subjected to a two-step acid digestion to extract 27 metals of interest. Concentrations across the four landfill sites were 58±6mgkg(-1) for REEs comprising 44±8mgkg(-1) for light REEs, 11±2mgkg(-1) for heavy REEs and 3±1mgkg(-1) for Scandium (Sc) and 3±1.0mgkg(-1) of PGMs. Compared to the typical concentration in ores, these concentrations are too low to achieve a commercially viable extraction. However, content of other highly valuable metals (Al and Cu) was found in concentrations equating to a combined value across the four landfills of around $400 million, which increases the economic viability of landfill mining. Presence of critical metals will mainly depend on the type of waste that was buried but the recovery of these metals through landfill mining is possible and is economically feasible only if additional materials (plastics, paper, metallic items and other) are also recovered for reprocessing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. A volatile rich Earth's core?

    NASA Astrophysics Data System (ADS)

    Morard, G.; Antonangeli, D.; Andrault, D.; Nakajima, Y.

    2017-12-01

    The composition of the Earth's core is still an open question. Although mostly composed of iron, it contains impurities that lower its density and melting point with respect to pure Fe. Knowledge of the nature and abundance of light elements (O, S, Si, C or H) in the core has major implications for establishing the bulk composition of the Earth and for building the model of Earth's differentiation. Geochemical models of the Earth's formation point out that its building blocks were depleted in volatile elements compared to the chondritic abundance, therefore light elements such as S, H or C cannot be the major elements alloyed with iron in the Earth's core. However, such models should be compatible with the comparison of seismic properties of the Earth's core and physical properties of iron alloys under extreme conditions, such as sound velocity or density of solid and liquid. The present work will discuss the recent progress for compositional model issued from studies of phase diagrams and elastic properties of iron alloys under core conditions and highlight the compatibility of volatile elements with observed properties of the Earth's core, in potential contradiction with models derived from metal-silicate partitioning experiments.

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

    NASA Astrophysics Data System (ADS)

    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 decrease in chlorinity suggests that these changes may be due to the breakdown of olivine and the formation of serpentine and Fe-hydroxy chlorides. Regardless of the starting solid reactants, fluid REE patterns were dominantly controlled by w/r. Atypical fluid REE patterns and high fluid REE contents were obtained at high w/r (⩾5). Whereas typical REE patterns known from many mid-ocean ridge vent fluids, showing relative enrichments of light REEs and a positive Eu anomaly, were obtained at low w/r of 0.5-1. Our results hence clearly show that REE contents and patterns of vent fluids are sensitive to variations in the w/r.

  4. A novel approach for acid mine drainage pollution biomonitoring using rare earth elements bioaccumulated in the freshwater clam Corbicula fluminea.

    PubMed

    Bonnail, Estefanía; Pérez-López, Rafael; Sarmiento, Aguasanta M; Nieto, José Miguel; DelValls, T Ángel

    2017-09-15

    Lanthanide series have been used as a record of the water-rock interaction and work as a tool for identifying impacts of acid mine drainage (lixiviate residue derived from sulphide oxidation). The application of North-American Shale Composite-normalized rare earth elements patterns to these minority elements allows determining the origin of the contamination. In the current study, geochemical patterns were applied to rare earth elements bioaccumulated in the soft tissue of the freshwater clam Corbicula fluminea after exposure to different acid mine drainage contaminated environments. Results show significant bioaccumulation of rare earth elements in soft tissue of the clam after 14 days of exposure to acid mine drainage contaminated sediment (ΣREE=1.3-8μg/gdw). Furthermore, it was possible to biomonitor different degrees of contamination based on rare earth elements in tissue. The pattern of this type of contamination describes a particular curve characterized by an enrichment in the middle rare earth elements; a homologous pattern (E MREE =0.90) has also been observed when applied NASC normalization in clam tissues. Results of lanthanides found in clams were contrasted with the paucity of toxicity studies, determining risk caused by light rare earth elements in the Odiel River close to the Estuary. The current study purposes the use of clam as an innovative "bio-tool" for the biogeochemical monitoring of pollution inputs that determines the acid mine drainage networks affection. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Chemistry of Selected Core Samples, Concentrate, Tailings, and Tailings Pond Waters: Pea Ridge Iron (-Lanthanide-Gold) Deposit, Washington County, Missouri

    USGS Publications Warehouse

    Grauch, Richard I.; Verplanck, Philip L.; Seeger, Cheryl M.; Budahn, James R.; Van Gosen, Bradley S.

    2010-01-01

    The Minerals at Risk and for Emerging Technologies Project of the U.S. Geological Survey (USGS) Mineral Resources Program is examining potential sources of lanthanide elements (rare earth elements) as part of its objective to provide up-to-date geologic information regarding mineral commodities likely to have increased demand in the near term. As part of the examination effort, a short visit was made to the Pea Ridge iron (-lanthanide-gold) deposit, Washington County, Missouri in October 2008. The deposit, currently owned by Wings Enterprises, Inc. of St. Louis, Missouri (Wings), contains concentrations of lanthanides that may be economic as a primary product or as a byproduct of iron ore production. This report tabulates the results of chemical analyses of the Pea Ridge samples and compares rare earth elements contents for world class lanthanide deposits with those of the Pea Ridge deposit. The data presented for the Pea Ridge deposit are preliminary and include some company data that have not been verified by the USGS or by the Missouri Department of Natural Resources, Division of Geology and Land Survey (DGLS), Geological Survey Program (MGS). The inclusion of company data is for comparative purposes only and does not imply an endorsement by either the USGS or MGS.

  6. The New Element Americium (Atomic Number 95)

    DOE R&D Accomplishments Database

    Seaborg, G.T.; James, R.A.; Morgan, L.O.

    1948-01-01

    Several isotopes of the new element 95 have been produced and their radiations characterized. The chemical properties of this tripositive element are similar to those of the typical tripositive lanthanide rare-earth elements. Element 95 is different from the latter in the degree and rate of formation of certain compounds of the complex ion type, which makes possible the separation of element 95 from the lanthanide rare-earths. The name americium (after the Americas) and the symbol Am are suggested for the element on the basis of its position as the sixth member of the actinide rare-earth series, analogous to europium, Eu, of the lanthanide series.

  7. Rare earth element mobility in vesicular lava during low-grade metamorphism

    NASA Astrophysics Data System (ADS)

    Nyström, Jan Olov

    1984-12-01

    A geochemical comparison of basaltic relicts and spilitic domains from two burial metamorphosed flows in central Chile, of similar original composition and rich and poor in amygdules, respectively, demonstrates a relationship between initial vesicularity and rare earth element (REE) mobility. During spilitization the REE were partly leached from permeable parts of the flows and precipitated in voids, now amygdules and veinlets. The REE (excluding Eu) moved coherently in the highly amygdaloidal flow: spilitic domains and amygdules inherited the basaltic REE pattern. Besides being characterized by a positive Eu anomaly, epidotes separated from amygdules have a REE distribution which mimics that of the basalt; the absolute contents range widely, suggesting local and/or temporal REE variations in the metamorphic fluids. Pumpellyite differs by being strongly enriched in heavy REE. Similar ratios of Th, Hf and Ta in samples as contrasting as relict basalt and a geode are consistent with coherent leaching. Coherent mobility, when established for a rock system, can be used to elucidate, for example, whether minerals in cross-cutting veins were formed by local redistribution or from introduced material.

  8. Rare earth element distribution in some hydrothermal minerals: evidence for crystallographic control

    USGS Publications Warehouse

    Morgan, J.W.; Wandless, G.A.

    1980-01-01

    Rare earth element (REE) abundances were measured by neutron activation analysis in anhydrite (CaSO4), barite (BaSO4), siderite (FeCO3) and galena (PbS). A simple crystal-chemical model qualitatively describes the relative affinities for REE substitution in anhydrite, barite, and siderite. When normalized to 'crustal' abundances (as an approximation to the hydrothermal fluid REE pattern), log REE abundance is a surprisingly linear function of (ionic radius of major cation-ionic radius of REE)2 for the three hydrothermal minerals, individually and collectively. An important exception, however, is Eu, which is anomalously enriched in barite and depleted in siderite relative to REE of neighboring atomic number and trivalent ionic radius. In principle, REE analyses of suitable pairs of co-existing hydrothermal minerals, combined with appropriate experimental data, could yield both the REE content and the temperature of the parental hydrothermal fluid. The REE have only very weak chalcophilic tendencies, and this is reflected by the very low abundances in galena-La, 0.6 ppb; Sm, 0.06 ppb; the remainder are below detection limits. ?? 1980.

  9. Shock compression of Fe-Ni-Si system to 280 GPa: Implications for the composition of the Earth's outer core

    NASA Astrophysics Data System (ADS)

    Zhang, Youjun; Sekine, Toshimori; He, Hongliang; Yu, Yin; Liu, Fusheng; Zhang, Mingjian

    2014-07-01

    The shock Hugoniot of an Fe-9 wt %Ni-10 wt %Si system as a model of the Earth's core has been measured up to ~280 GPa using a two-stage light-gas gun. The samples had an average density of 6.853 (±0.036) g/cm3. The relationship between shock velocity (Us) and particle velocity (up) can be described by Us (km/s) = 3.95 (±0.15) + 1.53 (±0.05) up (km/s). The calculated Hugoniot temperatures and the melting curve indicate that the model composition melts above a shock pressure of ~168 GPa, which is significantly lower than the shock-melting pressure of iron (~225 GPa). A comparison of the pressure-density (P-ρ) profiles between the model composition and the preliminary reference Earth model gives a silicon content close to 10 wt %, necessary to compensate the density deficit in the Earth's outer core from seismological observations, if silicon is present as a major light element in the Fe-Ni core system.

  10. Water Contents of the Mantle Beneath the Rio Grande Rift: FTIR Analysis of Kilbourne Hole Peridotite Xenoliths

    NASA Technical Reports Server (NTRS)

    Schaffer, Lillian A.; Peslier, Anne; Brandon, Alan

    2013-01-01

    Although nominally anhydrous mantle minerals contain only trace amounts of water, they are the main reservoir of water in the mantle. Added up at the scale of the Earth's mantle, these trace amounts of water represent oceans worth in mass]. Mantle xenoliths from Kilbourne Hole in southern New Mexico are ideal to study mantle water distribution in a rift tectonic setting as they come from a recently-erupted maar in the middle of the Rio Grande Rift. Eleven lherzolites, one harzburgite, and one dunite are being analyzed for water contents by FTIR. The xenoliths will also be analyzed for major and trace element composition, Fe3+/Summation (Fe) ratios, and characterized petrologically. Olivines exhibit variable water contents with less water at the rims compared to the cores. This is probably due to H loss during decompression and xenolith transport by the host magma. Mantle water contents appear to have been primarily preserved in the core of the olivines, based on diffusion modeling of the typically plateau-shaped water content profiles across these grains. Water concentrations are in equilibrium between clino- and orthopyroxene, but olivine concentrations are typically not in equilibrium with those of either pyroxene. Lherzolites analyzed so far have water contents of 2-12 ppm H2O in olivines, 125-165 ppm H2O in orthopyroxenes, and 328-447 ppm H2O in clinopyroxenes. These water contents are similar to, but with a narrower range, than those for the respective minerals in other continental peridotite xenoliths. The lherzolites have bulk-rock (BR) Al2O3 contents that range between 3.17 and 3.78 wt%, indicating similar degrees of partial melting, which could explain the narrow range of their pyroxene water contents. Primitive mantle normalized rare earth element (REE) profiles of the bulk lherzolites vary from light REE depleted to flat, with no significant differences between, nor relation to, their mineral water contents. Consequently, the metasomatic agents that enriched LREEs in these lherzolites were most likely water-poor. The harzburgite and the dunite have lower weight percent Al2O3 compared to the lherzolites (2.11% and 0.34% respectively) indicating higher degrees of melting. Their olivine water contents, however, are similar to those of the lherzolites. Moreover, no correlations are observed between pyroxene water contents and indices of melting or metasomatism between the lherzolite group, the harzburgite, and the dunite, although the latter has the lowest pyroxene water contents. More samples will be analyzed to determine if the water contents are controlled by melting, metasomatism, or a combination of the two in the Kilbourne Hole mantle.

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

    NASA Technical Reports Server (NTRS)

    Harrison, W. J.

    1981-01-01

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

  12. The elemental abundances (with uncertainties) of the most Earth-like planet

    NASA Astrophysics Data System (ADS)

    Wang, Haiyang S.; Lineweaver, Charles H.; Ireland, Trevor R.

    2018-01-01

    To first order, the Earth as well as other rocky planets in the Solar System and rocky exoplanets orbiting other stars, are refractory pieces of the stellar nebula out of which they formed. To estimate the chemical composition of rocky exoplanets based on their stellar hosts' elemental abundances, we need a better understanding of the devolatilization that produced the Earth. To quantify the chemical relationships between the Earth, the Sun and other bodies in the Solar System, the elemental abundances of the bulk Earth are required. The key to comparing Earth's composition with those of other objects is to have a determination of the bulk composition with an appropriate estimate of uncertainties. Here we present concordance estimates (with uncertainties) of the elemental abundances of the bulk Earth, which can be used in such studies. First we compile, combine and renormalize a large set of heterogeneous literature values of the primitive mantle (PM) and of the core. We then integrate standard radial density profiles of the Earth and renormalize them to the current best estimate for the mass of the Earth. Using estimates of the uncertainties in i) the density profiles, ii) the core-mantle boundary and iii) the inner core boundary, we employ standard error propagation to obtain a core mass fraction of 32.5 ± 0.3 wt%. Our bulk Earth abundances are the weighted sum of our concordance core abundances and concordance PM abundances. Unlike previous efforts, the uncertainty on the core mass fraction is propagated to the uncertainties on the bulk Earth elemental abundances. Our concordance estimates for the abundances of Mg, Sn, Br, B, Cd and Be are significantly lower than previous estimates of the bulk Earth. Our concordance estimates for the abundances of Na, K, Cl, Zn, Sr, F, Ga, Rb, Nb, Gd, Ta, He, Ar, and Kr are significantly higher. The uncertainties on our elemental abundances usefully calibrate the unresolved discrepancies between standard Earth models under various geochemical and geophysical assumptions.

  13. TRUST: A Successful Formal-Informal Teacher Education Partnership Designed to Improve and Promote Urban Earth Science Education

    NASA Astrophysics Data System (ADS)

    Sloan, H.; Drantch, K.; Steenhuis, J.

    2006-12-01

    We present an NSF-funded collaborative formal-informal partnership for urban Earth science teacher preparation and professional development. This model brings together The American Museum of Natural History (AMNH) and Brooklyn and Lehman College of the City University of New York (CUNY) to address science-impoverished classrooms that lack highly qualified teachers by focusing on Earth science teacher certification. Project design was based on identified needs in the local communities and schools, careful analysis of content knowledge mastery required for Earth science teacher certification, and existing impediments to certification. The problem-based approach required partners to push policy envelopes and to invent new ways of articulating content and pedagogy at both intra- and inter-institutional levels. One key element of the project is involvement of the local board of education, teachers, and administrators in initial design and ongoing assessment. Project components include formal Earth systems science courses, a summer institute primarily led and delivered by AMNH scientists through an informal series of lectures coupled to workshops led by AMNH educators, a mechanism for assigning course credit for informal experiences, development of new teaching approaches that include teacher action plans and an external program of evaluation. The principal research strand of this project focuses on the resulting model for formal-informal teacher education partnership, the project's impact on participating teachers, policy issues surrounding the model and the changes required for its development and implementation, and its potential for Earth science education reform. As the grant funded portion of the project draws to a close we begin to analyze data collected over the past 3 years. Third-year findings of the project's external evaluation indicate that the problem-based approach has been highly successful, particularly its impact on participating teachers. In addition to presenting these results, participating teachers from the 2004 and 2006 cohorts discuss their TRUST experiences and the subsequent impact the program has had on their respective Earth science teaching practices and professional lives.

  14. Strategic Materials in the Automobile: A Comprehensive Assessment of Strategic and Minor Metals Use in Passenger Cars and Light Trucks.

    PubMed

    Field, Frank R; Wallington, Timothy J; Everson, Mark; Kirchain, Randolph E

    2017-12-19

    A comprehensive component-level assessment of several strategic and minor metals (SaMMs), including copper, manganese, magnesium, nickel, tin, niobium, light rare earth elements (LREEs; lanthanum, cerium, praseodymium, neodymium, promethium, and samarium), cobalt, silver, tungsten, heavy rare earth elements (yttrium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium), and gold, use in the 2013 model year Ford Fiesta, Focus, Fusion, and F-150 is presented. Representative material contents in cars and light-duty trucks are estimated using comprehensive, component-level data reported by suppliers. Statistical methods are used to accommodate possible errors within the database and provide estimate bounds. Results indicate that there is a high degree of variability in SaMM use and that SaMMs are concentrated in electrical, drivetrain, and suspension subsystems. Results suggest that trucks contain greater amounts of aluminum, nickel, niobium, and silver and significantly greater amounts of magnesium, manganese, gold, and LREEs. We find tin and tungsten use in automobiles to be 3-5 times higher than reported by previous studies which have focused on automotive electronics. Automotive use of strategic and minor metals is substantial, with 2013 vehicle production in the United States, Canada, EU15, and Japan alone accounting for approximately 20% of global production of Mg and Ta and approximately 5% of Al, Cu, and Sn. The data and analysis provide researchers, recyclers, and decision-makers additional insight into the vehicle content of strategic and minor metals of current interest.

  15. Properties of Sn3.8Ag0.7Cu Solder Alloy with Trace Rare Earth Element Y Additions

    NASA Astrophysics Data System (ADS)

    Hao, H.; Tian, J.; Shi, Y. W.; Lei, Y. P.; Xia, Z. D.

    2007-07-01

    In the current research, trace rare earth (RE) element Y was incorporated into a promising lead-free solder, Sn3.8Ag0.7Cu, in an effort to improve the comprehensive properties of Sn3.8Ag0.7Cu solder. The range of Y content in Sn3.8Ag0.7Cu solder alloys varied from 0 wt.% to 1.0 wt.%. As an illustration of the advantage of Y doping, the melting temperature, wettability, mechanical properties, and microstructures of Sn3.8Ag0.7CuY solder were studied. Trace Y additions had little influence on the melting behavior, but the solder showed better wettability and mechanical properties, as well as finer microstructures, than found in Y-free Sn3.8Ag0.7Cu solder. The Sn3.8Ag0.7Cu0.15Y solder alloy exhibited the best comprehensive properties compared to other solders with different Y content. Furthermore, interfacial and microstructural studies were conducted on Sn3.8Ag0.7Cu0.15Y solder alloys, and notable changes in microstructure were found compared to the Y-free alloy. The thickness of an intermetallic compound layer (IML) was decreased during soldering, and the growth of the IML was suppressed during aging. At the same time, the growth of intermetallic compounds (IMCs) inside the solder was reduced. In particular, some bigger IMC plates were replaced by fine, granular IMCs.

  16. Comparing early twentieth century and present-day atmospheric pollution in SW France: A story of lichens.

    PubMed

    Agnan, Y; Séjalon-Delmas, N; Probst, A

    2013-01-01

    Lichens have long been known to be good indicators of air quality and atmospheric deposition. Xanthoria parietina was selected to investigate past (sourced from a herbarium) and present-day trace metal pollution in four sites from South-West France (close to Albi). Enrichment factors, relationships between elements and hierarchical classification indicated that the atmosphere was mainly impacted by coal combustion (as shown by As, Pb or Cd contamination) during the early twentieth century, whereas more recently, another mixture of pollutants (e.g. Sb, Sn, Pb and Cu) from local factories and car traffic has emerged. The Rare Earth Elements (REE) and other lithogenic elements indicated a higher dust content in the atmosphere in the early twentieth century and a specific lithological local signature. In addition to long-range atmospheric transport, local urban emissions had a strong impact on trace element contamination registered in lichens, particularly for contemporary data. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Semiconductor sensor for optically measuring polarization rotation of optical wavefronts using rare earth iron garnets

    DOEpatents

    Duncan, Paul G.

    2002-01-01

    Described are the design of a rare earth iron garnet sensor element, optical methods of interrogating the sensor element, methods of coupling the optical sensor element to a waveguide, and an optical and electrical processing system for monitoring the polarization rotation of a linearly polarized wavefront undergoing external modulation due to magnetic field or electrical current fluctuation. The sensor element uses the Faraday effect, an intrinsic property of certain rare-earth iron garnet materials, to rotate the polarization state of light in the presence of a magnetic field. The sensor element may be coated with a thin-film mirror to effectively double the optical path length, providing twice the sensitivity for a given field strength or temperature change. A semiconductor sensor system using a rare earth iron garnet sensor element is described.

  18. Stratospheric Sampling and In Situ Atmospheric Chemical Element Analysis During Meteor Showers: A Resource Study

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    2000-01-01

    Resources studies for asteroidal mining evaluation have depended historically on remote sensing analysis for chemical elements. During the November 1998 Leonids meteor shower, a stratospheric balloon and various low-density capture media were used to sample fragments from Comet Tempel-Tuttle debris during a peak Earth crossing. The analysis not only demonstrates how potential sampling strategies may improve the projections for metals or rare elements in astromining, but also benchmarks materials during low temperature (-60 F), high dessication environments as seen during atmospheric exposure. The results indicate high aluminum, magnesium and iron content for various sampled particles recovered, but generalization to the sporadic meteors expected from asteroidal sources will require future improvements in larger sampling volumes before a broad-use strategy for chemical analysis can be described. A repeat of the experimental procedure is planned for the November 1999 Leonids' shower, and various improvements for atmospheric sampling will be discussed.

  19. Condensation and fractionation of rare earths in the solar nebula

    NASA Technical Reports Server (NTRS)

    Davis, A. M.; Grossman, L.

    1979-01-01

    The condensation behavior of the rare earth elements in the solar nebula is calculated on the basis of the most recent thermodynamic data in order to construct a model explaining group II rare earth element patterns in Allende inclusions. Models considered all involve the removal of large fractions of the more refractory heavy rare earth elements in an early condensate, followed by the condensation of the remainder at a lower temperature. It is shown that the model of Boynton (1975) in which one rare earth element component is dissolved nonideally in perovskite according to relative activity coefficients can not reasonably be made to fit the observed group II patterns. A model in which two rare earth components control the patterns and dissolve ideally in perovskite is proposed and shown to be able to account for the 20 patterns by variations of the perovskite removal temperature and the relative proportions of the two components.

  20. Membrane assisted solvent extraction for rare earth element recovery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bhave, Ramesh R.; Kim, Daejin; Peterson, Eric S.

    Systems and methods for the recovery of rare earth elements are provided. The systems and methods generally include membrane assisted solvent extraction using permeable hollow fibers having an immobilized organic phase within the pores of the hollow fibers. The permeable hollow fibers are generally in contact with an acidic aqueous feed on one side thereof and a strip solution on another side thereof. The systems and methods generally include the simultaneous extraction and stripping of rare earth elements as a continuous recovery process that is well suited for post-consumer products, end-of-life products, and other recovery sources of rare earth elements.

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

    USGS Publications Warehouse

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

    1997-01-01

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

  2. MaRGEE: Move and Rotate Google Earth Elements

    NASA Astrophysics Data System (ADS)

    Dordevic, Mladen M.; Whitmeyer, Steven J.

    2015-12-01

    Google Earth is recognized as a highly effective visualization tool for geospatial information. However, there remain serious limitations that have hindered its acceptance as a tool for research and education in the geosciences. One significant limitation is the inability to translate or rotate geometrical elements on the Google Earth virtual globe. Here we present a new JavaScript web application to "Move and Rotate Google Earth Elements" (MaRGEE). MaRGEE includes tools to simplify, translate, and rotate elements, add intermediate steps to a transposition, and batch process multiple transpositions. The transposition algorithm uses spherical geometry calculations, such as the haversine formula, to accurately reposition groups of points, paths, and polygons on the Google Earth globe without distortion. Due to the imminent deprecation of the Google Earth API and browser plugin, MaRGEE uses a Google Maps interface to facilitate and illustrate the transpositions. However, the inherent spatial distortions that result from the Google Maps Web Mercator projection are not apparent once the transposed elements are saved as a KML file and opened in Google Earth. Potential applications of the MaRGEE toolkit include tectonic reconstructions, the movements of glaciers or thrust sheets, and time-based animations of other large- and small-scale geologic processes.

  3. Titanium-bearing phases in the Earth's mantle (evidence from experiments in the MgO-SiO2-TiO2 ±Al2O3 system at 10-24 GPa)

    NASA Astrophysics Data System (ADS)

    Sirotkina, Ekaterina; Bobrov, Andrey; Bindi, Luca; Irifune, Tetsuo

    2017-04-01

    Introduction Despite significant interest of experimentalists to the study of geophysically important phase equilibria in the Earth's mantle and a huge experimental database on a number of the model and multicomponent systems, incorporation of minor elements in mantle phases was mostly studied on a qualitative level. The influence of such elements on structural peculiarities of high-pressure phases is poorly investigated, although incorporation of even small portions of them may have a certain impact on the PT-parameters of phase transformations. Titanium is one of such elements with the low bulk concentrations in the Earth's mantle (0.2 wt % TiO2) [1]; however, Ti-rich lithologies may occur in the mantle as a result of oceanic crust subduction. Thus, the titanium content is 0.6 wt% in Global Oceanic Subducted Sediments (GLOSS) [2], and 1.5 wt% TiO2, in MORB [3]. In this regard, accumulation of titanium in the Earth's mantle is related to crust-mantle interaction during the subduction of crustal material at different depths of the mantle. Experimental methods At 10-24 GPa and 1600°C, we studied the full range of the starting materials in the MgSiO3 (En) - MgTiO3 (Gkl) system in increments of 10-20 mol% Gkl and 1-3 GPa, which allowed us to plot the phase PX diagram for the system MgSiO3-MgTiO3 and synthesize titanium-bearing phases with a wide compositional range. The experiments were performed using a 2000-t Kawai-type multi-anvil high-pressure apparatus at the Geodynamics Research Center, Ehime University (Japan). The quenched samples were examined by single-crystal X-ray diffractometer, and the composition of phases was analyzed using SEM-EDS. Results The main phases obtained in experiments were rutile, wadsleyite, MgSiO3-enstatite, MgTiO3-ilmenite, MgTiSi2O7 with the weberite structure type (Web), Mg(Si,Ti)O3 and MgSiO3 with perovskite-type structure. At a pressure of 13 GPa for Ti-poor bulk compositions, an association of En+Wad+Rt is replaced by the paragenesis of Web+Wad+Rt. With increasing Glk content in the starting composition, Gkl+Wad+Rt association is formed. At a pressure of >17 GPa, an association of two phases with Prv-type structure is stable within a narrow range of starting compositions. Addition of Al to the starting material allows us to simulate the composition of natural bridgmanites, since lower mantle bridgmanites are characterized by significant Al contents. In addition, this study shows that, in contrast to Al, the high contents of Ti can stabilize bridgmanite-like compounds at considerably lower pressure (18 GPa) in comparison with pure MgSiO3 bridgmanite. Small crystals of titanium-rich phases, including Ti-Al-Brd and Web were examined by single-crystal X-ray diffractometer, which allowed us to study the influence of Ti on crystallochemical peculiarities of the mantle phases and on the phase transformations. This study was supported by the Foundation of the President of the Russian Federation for Young Ph.D. (projects no. MK 1277.2017.5 to E.A. Sirotkina) and partly supported by the Russian Foundation for Basic Research (project nos. 17-55-50062 to E.A. Sirotkina and A.V.Bobrov) [1] Ringwood, A.E. The chemical composition and origin of the Earth. In: Advances in Earth science. Hurley, P.M. (Editors), M.I.T. Press, Cambridge. 1966. P. 287-356 [2] Plank, T., Langmuir, C.H., 1998. The chemical composition of subducting sediment and its consequences for the crust and mantle. Chemical Geology 145, 325-394. [3] Wilson, M. (1989) Igneous Petrogenesis—A global tectonic approach, 466 p. Kluwer, Dordrecht.

  4. Evolution of the earth's crust: Evidence from comparative planetology

    NASA Technical Reports Server (NTRS)

    Lowman, P. D., Jr.

    1973-01-01

    Geochemical data and orbital photography from Apollo, Mariner, and Venera missions were combined with terrestrial geologic evidence to study the problem of why the earth has two contrasting types of crust (oceanic and continental). The following outline of terrestrial crustal evolution is proposed. A global crust of intermediate to acidic composition, high in aluminum, was formed by igneous processes early in the earth's history; portions survive in some shield areas as granitic and anorthositic gneisses. This crust was fractured by major impacts and tectonic processes, followed by basaltic eruptions analogous to the lunar maria and the smooth plains of the north hemisphere of Mars. Seafloor spreading and subduction ensued, during which portions of the early continental crust and sediments derived therefrom were thrust under the remaining continental crust. The process is exemplified today in regions such as the Andes/Peru-Chile trench system. Underplating may have been roughly concentric, and the higher radioactive element content of the underplated sialic material could thus eventually cause concentric zones of regional metamorphism and magmatism.

  5. Selective liquid chromatographic separation of yttrium from heavier rare earth elements using acetic acid as a novel eluent.

    PubMed

    Kifle, Dejene; Wibetoe, Grethe

    2013-09-13

    One of the major difficulties in the rare earth elements separation is purification of yttrium from heavy rare earth elements. Thus, an HPLC method using acetic acid as novel eluent was explored for selective separation of yttrium form the heavy rare earth elements. When acetic acid is used as a mobile phase yttrium eluted with the lighter lanthanides. This is contrary to its relative position amongst heavier lanthanides when eluents commonly used for separation of rare earth elements were employed. The shift in elution position of yttrium with acetic acid as eluent may reflect a relatively lower stability constant of the yttrium-AcOH complex (in the same order as for the lighter lanthanides) compared to the corresponding AcOH complexes with heavy lanthanides, enabling selective separation of yttrium from the latter. The method was successfully used for selective separation of yttrium in mixed rare earth sample containing about 80% of yttrium and about 20% of heavy rare earth oxides. Thus, the use of AcOH as eluent is an effective approach for separating and determining the trace amounts of heavy rare earth elements in large amounts of yttrium matrix. Separation was performed on C18 column by running appropriate elution programs. The effluent from the column was monitored with diode array detector at absorbance wavelength of 658nm after post column derivatization with Arsenazo III. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Ternary alkali-metal and transition metal or metalloid acetylides as alkali-metal intercalation electrodes for batteries

    DOEpatents

    Nemeth, Karoly; Srajer, George; Harkay, Katherine C; Terdik, Joseph Z

    2015-02-10

    Novel intercalation electrode materials including ternary acetylides of chemical formula: A.sub.nMC.sub.2 where A is alkali or alkaline-earth element; M is transition metal or metalloid element; C.sub.2 is reference to the acetylide ion; n is an integer that is 0, 1, 2, 3 or 4 when A is alkali element and 0, 1, or 2 when A is alkaline-earth element. The alkali elements are Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). The alkaline-earth elements are Berilium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). M is a transition metal that is any element in groups 3 through 12 inclusive on the Periodic Table of Elements (elements 21 (Sc) to element 30 (Zn)). In another exemplary embodiment, M is a metalloid element.

  7. RARE EARTH ELEMENTS: A REVIEW OF PRODUCTION, PROCESSING, RECYCLING, AND ASSOCIATED ENVIRONMENTAL ISSUES

    EPA Science Inventory

    Rare earth elements (REEs) are a group of 15 chemical elements in the periodic table, specifically the lanthanides. Two other elements, scandium and yttrium, have a similar physiochemistry to the lanthanides, are commonly found in the same mineral assemblages, and are often refe...

  8. A middle Permian ophiolite fragment in Late Triassic greenschist- to blueschist-facies rocks in NW Turkey: An earlier pulse of suprasubduction-zone ophiolite formation in the Tethyan belt

    NASA Astrophysics Data System (ADS)

    Topuz, Gültekin; Okay, Aral I.; Schwarz, Winfried H.; Sunal, Gürsel; Altherr, Rainer; Kylander-Clark, Andrew R. C.

    2018-02-01

    The Eastern Mediterranean region within the Tethyan belt is characterised by two main pulses of suprasubduction-zone ophiolite formation during the Early-Middle Jurassic and Late Cretaceous. Despite vast exposures of the Permo-Triassic accretionary complexes, related suprasubduction-zone ophiolites and the timing of subduction initiation leading to the formation of Permo-Triassic accretionary complexes are unknown so far. Here we report on a 40 km long and 0.3 to 1.8 km wide metaophiolite fragment within transitional greenschist- to blueschist-facies oceanic rocks from NW Turkey. The metaophiolite fragment is made up mainly of serpentinite and minor dykes or stocks of strongly sheared metagabbro with mineral assemblages involving actinolite/winchite, chlorite, epidote, albite, titanite and phengite. The metagabbro displays (i) variable CaO and MgO contents, (ii) anomalously high Mg# (= 100 ∗ molar MgO/(MgO + FeOtot)) of 75-88, and (iii) positive Eu anomalies, together with low contents of incompatible elements such as Ti, P and Zr, suggesting derivation from former plagioclase cumulates. The serpentinites comprise serpentine, ± chlorite, ± talc, ± calcite and relict Cr-Al spinel surrounded by ferrichromite to magnetite. Relict Cr-Al spinels are characterised by (i) Cr/(Cr + Al) ratios of 0.45-0.56 and Mg/(Mg + Fe2 +) ratio of 0.76-0.22, (ii) variable contents of ZnO and MnO, and (iii) extremely low TiO2 contents. Zn and Mn contents are probably introduced into Cr-Al spinels during greenschist- to blueschist metamorphism. Compositional features of the serpentinite such as (i) Ca- and Al-depleted bulk compositions, (ii) concave U-shaped, chondrite-normalised rare earth element patterns (REE) with enrichment of light and heavy REEs, imply that serpentinites were probably derived from depleted peridotites which were refertilised by light rare earth element enriched melts in a suprasubduction-zone mantle wedge. U-Pb dating on igneous zircons from three metagabbro samples indicates igneous crystallisation at 262 Ma (middle Permian). Timing of the metamorphism is constrained by incremental 40Ar/39Ar dating on phengitic white mica at 201 Ma (latest Triassic). We conclude that the metaophiolite represents a fragment of middle Permian suprasubduction-zone oceanic lithosphere, involved in a latest Triassic subduction zone. These data, together with several reports in literature, indicate that the middle Permian was a time of suprasubduction-zone ophiolite formation in the Tethyan belt.

  9. K, U, and Th behavior in Martian environmental conditions

    NASA Technical Reports Server (NTRS)

    Zolotov, M. YU.; Krot, T. V.; Moroz, L. V.

    1993-01-01

    The possibility of K, U, and Th content determination from orbit and in situ allows consideration of those elements as geochemical indicators in the planetary studies. In the case of Mars the unambiguous interpretations of such data in terms of igneous rocks are remarkably constrained by the widespread rock alteration and the existence of exogenic deposits. Besides, the terrestrial experience indicates that K, U, and Th contents could be used as indicators of environmental geochemical processes. Thus the determination of K, U, and Th contents in the Martian surface materials could provide the indirect data on the conditions of some exogenic geological processes. The speculations on the K, U, and Th behavior in the Martian environments show that aeolian and aqueous processes leads to the preferential accumulation of K, U, and Th in fine dust material. The separation of K, U, and Th on Mars is smaller in scale to that on Earth.

  10. The role of water content in triboelectric charging of wind-blown sand.

    PubMed

    Gu, Zhaolin; Wei, Wei; Su, Junwei; Yu, Chuck Wah

    2013-01-01

    Triboelectric charging is common in desert sandstorms and dust devils on Earth; however, it remains poorly understood. Here we show a charging mechanism of sands with the adsorbed water on micro-porous surface in wind-blown sand based on the fact that water content is universal but usually a minor component in most particle systems. The triboelectric charging could be resulted due to the different mobility of H(+)/OH(-) between the contacting sands with a temperature difference. Computational fluid dynamics (CFD) and discrete element method (DEM) were used to demonstrate the dynamics of the sand charging. The numerically simulated charge-to-mass ratios of sands and electric field strength established in wind tunnel agreed well with the experimental data. The charging mechanism could provide an explanation for the charging process of all identical granular systems with water content, including Martian dust devils, wind-blown snow, even powder electrification in industrial processes.

  11. The role of water content in triboelectric charging of wind-blown sand

    PubMed Central

    Gu, Zhaolin; Wei, Wei; Su, Junwei; Yu, Chuck Wah

    2013-01-01

    Triboelectric charging is common in desert sandstorms and dust devils on Earth; however, it remains poorly understood. Here we show a charging mechanism of sands with the adsorbed water on micro-porous surface in wind-blown sand based on the fact that water content is universal but usually a minor component in most particle systems. The triboelectric charging could be resulted due to the different mobility of H+/OH− between the contacting sands with a temperature difference. Computational fluid dynamics (CFD) and discrete element method (DEM) were used to demonstrate the dynamics of the sand charging. The numerically simulated charge-to-mass ratios of sands and electric field strength established in wind tunnel agreed well with the experimental data. The charging mechanism could provide an explanation for the charging process of all identical granular systems with water content, including Martian dust devils, wind-blown snow, even powder electrification in industrial processes. PMID:23434920

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

    PubMed

    Yang, Xiuli; Zhang, Junwei; Fang, Xihui

    2014-08-30

    With an increase in number of waste nickel-metal hydride batteries, and because of the importance of rare earth elements, the recycling of rare earth elements is becoming increasingly important. In this paper, we investigate the effects of temperature, hydrochloric acid concentration, and leaching time to optimize leaching conditions and determine leach kinetics. The results indicate that an increase in temperature, hydrochloric acid concentration, and leaching time enhance the leaching rate of rare earth elements. A maximum rare earth elements recovery of 95.16% was achieved at optimal leaching conditions of 70°C, solid/liquid ratio of 1:10, 20% hydrochloric acid concentration, -74μm particle size, and 100min leaching time. The experimental data were best fitted by a chemical reaction-controlled model. The activation energy was 43.98kJ/mol and the reaction order for hydrochloric acid concentration was 0.64. The kinetic equation for the leaching process was found to be: 1-(1-x)(1/3)=A/ρr0[HCl](0.64)exp-439,8008.314Tt. After leaching and filtration, by adding saturated oxalic solution to the filtrate, rare earth element oxalates were obtained. After removing impurities by adding ammonia, filtering, washing with dilute hydrochloric acid, and calcining at 810°C, a final product of 99% pure rare earth oxides was obtained. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Laboratory calibration and field testing of the Chemcatcher-Metal for trace levels of rare earth elements in estuarine waters.

    PubMed

    Petersen, Jördis; Pröfrock, Daniel; Paschke, Albrecht; Broekaert, Jose A C; Prange, Andreas

    2015-10-01

    Little knowledge is available about water concentrations of rare earth elements (REEs) in the marine environment. The direct measurement of REEs in coastal waters is a challenging task due to their ultra-low concentrations as well as the high salt content in the water samples. To quantify these elements at environmental concentrations (pg L(-1) to low ng L(-1)) in coastal waters, current analytical techniques are generally expensive and time consuming, and require complex chemical preconcentration procedures. Therefore, an integrative passive sampler was tested as a more economic alternative sampling approach for REE analysis. We used a Chemcatcher-Metal passive sampler consisting of a 3M Empore Chelating Disk as the receiving phase, as well as a cellulose acetate membrane as the diffusion-limiting layer. The effect of water turbulence and temperature on the uptake rates of REEs was analyzed during 14-day calibration experiments by a flow-through exposure tank system. The sampling rates were in the range of 0.42 mL h(-1) (13 °C; 0.25 m s(-1)) to 4.01 mL h(-1) (13 °C; 1 m s(-1)). Similar results were obtained for the different REEs under investigation. The water turbulence was the most important influence on uptake. The uptake rates were appropriate to ascertain time-weighted average concentrations of REEs during a field experiment in the Elbe Estuary near Cuxhaven Harbor (exposure time 4 weeks). REE concentrations were determined to be in the range 0.2 to 13.8 ng L(-1), where the highest concentrations were found for neodymium and samarium. In comparison, most of the spot samples measured along the Chemcatcher samples had REE concentrations below the limit of detection, in particular due to necessary dilution to minimize the analytical problems that arise with the high salt content in marine water samples. This study was among the first efforts to measure REE levels in the field using a passive sampling approach. Our results suggest that passive samplers could be an effective tool to monitor ultra-trace concentrations of REEs in coastal waters with high salt content.

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

    PubMed

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

    2013-10-01

    Rare earth minerals have been mined for more than 50 years in Inner Mongolia of China. In the mining area rare earth elements (REE) may be significantly accumulated in humans. Therefore, the aim of this paper is to characterize the REE concentrations in hair of local residents. REE concentrations in hair of 118 subjects were determined. The results showed that the mean concentrations of the determined REE in the hair of both females and males were usually higher from mining area than from control area. The mean concentrations of all the fifteen REE were much higher in hair of males than in hair of females from mining area. This suggested that males might be more sensitive to REE than females. In addition, the mean contents of the REE in hair of miners, particularly light REE (La, Ce, Pr and Nd), were usually much higher than the values in hair of non-miners from both mining area and control area, indicating that the miners were exposed to higher concentrations of REE in occupational environment. Among age groups, the relationships between REE concentrations and age groups showed that more and more concentrations of light REE accumulated in body of both females and males with age until 60 years, while heavy REE concentrations decreased with age in males who were exposed to low concentrations of heavy REE. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Geology and description of thorium and rare-earth deposits in the southern Bear Lodge Mountains, northeastern Wyoming

    USGS Publications Warehouse

    Staatz, M.H.

    1983-01-01

    The Bear Lodge Mountains are a small northerly trending range approximately 16 km northwest of the Black Hills in the northeast corner of Wyoming. Thorium and rare-earth deposits occur over an area of 16 km 2 in the southern part of these mountains. These deposits occur in the core of the Bear Lodge dome in a large multiple intrusive body made up principally of trachyte and phonolite. Two types of deposits are recognized: disseminated deposits and veins. The disseminated deposits are made up of altered igneous rocks cut by numerous crisscrossing veinlets. The disseminated deposits contain thorium and rare-earth minerals in a matrix consisting principally of potassium feldspar, quartz, and iron and manganese oxides. Total rare-earth content of these deposits is about 27 times that of the thorium content. The general size and shape of the disseminated deposits were outlined by making a radiometric map using a scintillation counter of the entire Bear Lodge core, an area of approximately 30 km 2 . The most favorable part of this area, which was outlined by the 40 countJs (count-per-second) isograd on the radiometric map, was sampled in detail. A total of 341 samples were taken over an area of 10.6 km 2 and analyzed for as many as 60 elements. Rare earths and thorium are the principal commodities of interest in these deposits. Total rare-earth content of these samples ranged from 47 to 27,145 ppm (parts per million), and the thorium content from 9.3 to 990 ppm. The amount of total rare earths of individual samples shows little correlation with that of thorium. Contour maps were constructed using the analytical data for total rare earths, thorium, uranium, and potassium. The total rare-earth and thorium maps can be used to define the size of the deposits based on what cut-off grade may be needed during mining. The size is large as the 2,000 ppm total rare-earth isograd encloses several areas that total 3.22 km 2 in size, and the 200 ppm thorium isograd encloses several areas that total 1.69 km 2 . These deposits could be mined by open pit. The Bear Lodge disseminated deposits have one of the largest resources of both total rare earths and thorium in the United States, and although the grade of both commodities is lower than some other deposits, their large size and relative cheapness of mining make them an important future resource. Vein deposits in the Bear Lodge Mountains include all tabular bodies at least 5 cm thick. Twenty-six veins were noted in this area. These veins are thin and short; the longest vein was traced for only 137 m. Minerals vary greatly in the amount present. Gangue minerals are commonly potassium feldspar, quartz, or cristobalite intermixed with varying amounts of limonite, hematite, and various manganese oxides. Rare earths and thorium occur in the minerals monazite, brockite, and bastnaesite. Thorium content of 35 samples ranged from 0.01 to 1.2 percent, and the total rare-earth content of 21 samples from 0.23 to 9.8 percent. Indicated reserves were calculated to a depth of one-third the exposed length of the vein. Inferred reserves lie in a block surrounding indicated reserves. Indicated reserves of all veins are only 50 t of Th0 2 and 1,360 t of total rare-earth oxides; inferred reserves are 250 t of Th0 2 and 6,810 t of total rare-earth oxides. The Bear Lodge dome, which underlies the greater part of this area, is formed by multiple intrusive bodies of Tertiary age that dome up the surrounding sedimentary rocks. In the southern part of the core, the younger intrusive bodies surround and partly replace a granite of Precambrian age. This granite is approximately 2.6 b.y. old. The sedimentary rocks around the core are (from oldest to youngest): Deadwood Formation of Late Cambrian and Early Ordovician age, Whitewood Limestone of Late Ordovician age, Pahasapa Limestone of Early Mississippian age, Minnelusa Sandstone of Pennsylvanian and Early Permian age, Opeche Formation of Permian age, Minnek

  16. Rare Earth Element Mines, Deposits, and Occurrences

    USGS Publications Warehouse

    Orris, Greta J.; Grauch, Richard I.

    2002-01-01

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

  17. Halogen content in Lesser Antilles arc volcanic rocks : exploring subduction recycling

    NASA Astrophysics Data System (ADS)

    Thierry, Pauline; Villemant, Benoit; Caron, Benoit

    2016-04-01

    Halogens (F, Cl, Br and I) are strongly reactive volatile elements which can be used as tracers of igneous processes, through mantle melting, magma differentiation and degassing or crustal material recycling into mantle at subduction zones. Cl, Br and I are higly incompatible during partial melting or fractional cristallization and strongly depleted in melts by H2O degassing, which means that no Cl-Br-I fractionation is expected through magmatic differenciation [current thesis]. Thus, Cl/Br/I ratios in lavas reflect the halogen content of their mantle sources. Whereas these ratios seemed quite constant (e.g. Cl/Br =300 as seawater), recent works suggest significant variations in arc volcanism [1,2]. In this work we provide high-precision halogen measurements in volcanic rocks from the recent activity of the Lesser Antilles arc (Montserrat, Martinique, Guadeloupe, Dominique). Halogen contents of powdered samples were determined through extraction in solution by pyrohydrolysis and analysed by Ion Chromatography for F and Cl and high performance ICP-MS (Agilent 8800 Tripe Quad) for Cl, Br and I [3,4]. We show that lavas - and mantle sources - display significant vraiations in Cl/Br/I ratios along the Lesser Antilles arc. These variations are compared with Pb, Nd and Sr isotopes and fluid-mobile elements (Ba, U, Sr, Pb etc.) compositions which vary along the arc from a nothern ordinary arc compositions to a southern 'crustal-like' composition [5,6]. These characteristics are attributed to subducted sediments recycling into the mantle wedge, whose contribution vary along the arc from north to south [7,8]. The proportion of added sediments is also related to the distance to the trench as sediment melting and slab dehydration may occur depending on the slab depth [9]. Further Cl-Br-I in situ measurements by LA-ICP-MS in Lesser Antilles arc lavas melt inclusions will be performed, in order to provide better constraints on the deep halogen recycling cycle from crust to mantle. 1. Villemant, B., Mouatt, J. & Michel, A., 2008. Earth Planet. Sci. Lett. 269(1), 212-229. 2. Kutterolf, S. et al., 2015. Earth Planet. Sci. Lett. 429, 234-246. 3. Michel, A. & Villemant, B., 2003. Geostand. Geoanalytical Res. 27(2), 163-171. 4. Balcone-Boissard, H., Michel, A. & Villemant, B., 2009. Geostand. Geoanalytical Res. 33(4), 477-485. 5. White, W. M. & Dupré, B., 1986. J. Geophys. Res. 91(B6), 5927. 6. Labanieh, S. et al., 2010. Earth Planet. Sci. Lett. 298(1-2), 35-46. 7. Turner, S. et al., 1996. Earth Planet. Sci. Lett. 142(1-2), 191-207. 8. Carpentier, M., Chauvel, C. & Mattielli, N., 2008. Earth Planet. Sci. Lett. 272(1-2), 199-211. 9. Labanieh, S. et al., 2012. J. Petrol. 53(12), 2441-2464.

  18. Cryptic trace-element alteration of Anorthosite, Stillwater complex, Montana

    USGS Publications Warehouse

    Czamanske, G.K.; Loferski, P.J.

    1996-01-01

    Evidence of cryptic alteration and correlations among K, Ba, and LREE concentrations indicate that a post-cumulus, low-density aqueous fluid phase significantly modified the trace-element contents of samples from Anorthosite zones I and II of the Stillwater Complex, Montana. Concentrations of Ba, Ca, Co, Cr, Cu, Fe, Hf, K, Li, Mg, Mn, Na, Ni, Sc, Sr, Th, Zn, and the rare-earth elements (REE) were measured in whole rocks and plagioclase separates from five traverses across the two main plagioclase cumulate (anorthosite) zones and the contiguous cumulates of the Stillwater Complex in an attempt to better understand the origin and solidification of the anorthosites. However, nearly the entire observed compositional range for many trace elements can be duplicated at a single locality by discriminating between samples rich in oikocrystic pyroxene and those which are composed almost entirely of plagioclase and show anhedral-granular texture. Plagioclase separates with high trace-element contents were obtained from the pyroxene-poor samples, for which maps of K concentration show plagioclase grains to contain numerous fractures hosting a fine-grained, K-rich phase, presumed to be sericite. Secondary processes in layered intrusions have the potential to cause cryptic disturbance, and the utmost care must be taken to ensure that samples provide information about primary processes. Although plagioclase from Anorthosite zones I and II shows significant compositional variation, there are no systematic changes in the major- or trace-element compositions of plagioclase over as much as 630 m of anorthosite thickness or 18 km of strike length. Plagioclase in the two major anorthosite zones shows little distinction in trace-element concentrations from plagioclase in the cumulates immediately below, between, and above these zones.

  19. NETL’s Rare Earth Elements Research

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None

    The National Energy Technology Laboratory has established a Rare Earth Elements (REE) program. REEs are a series of 17 chemical elements found in the Earth’s crust. They are an essential component to technology, health care, transportation and national defense.

  20. LA-ICP-MS trace element mapping: insights into the crystallisation history of a metamorphic garnet population

    NASA Astrophysics Data System (ADS)

    George, Freya; Gaidies, Fred

    2017-04-01

    In comparison to our understanding of major element zoning, relatively little is known about the incorporation of trace elements into metamorphic garnet. Given their extremely slow diffusivities and sensitivity to changing mineral assemblages, the analysis of the distribution of trace elements in garnet has the potential to yield a wealth of information pertaining to interfacial attachment mechanisms during garnet crystallisation, the mobility of trace elements in both garnet and the matrix, and trace element geochronology. Due to advances in the spatial resolution and analytical precision of modern microbeam techniques, small-scale trace element variations can increasingly be documented and used to inform models of metamorphic crystallisation. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) in particular, can be used to rapidly quantify a wide range of elemental masses as a series of laser rasters, producing large volumes of spatially constrained trace element data. In this study, we present LA-ICP-MS maps of trace element concentrations from numerous centrally-sectioned garnets representative of the crystal size-distribution of a single sample's population. The study sample originates from the garnet-grade Barrovian zone of the Lesser Himalayan Sequence in Sikkim, northeast India, and has been shown to have crystallised garnet within a single assemblage between 515 ˚C and 565˚C, with no evidence for accessory phase reaction over the duration of garnet growth. Previous models have indicated that the duration of garnet crystallisation was extremely rapid (<1 Myr), with negligible diffusional homogenisation of major divalent cations. Consequently, the trace element record likely documents the primary zonation generated during garnet growth. In spite of straightforward (i.e. concentrically-zoned) major element garnet zonation, trace elements maps are characterised by significant complexity and variability. Y and the heavy rare earth elements are strongly enriched in crystal cores, where there is overprinting of the observed internal fabric, and exhibit numerous concentric annuli towards crystal rims. Conversely, the medium rare earth elements (e.g. Gd, Eu and Sm) exhibit bowl-shaped zoning from core to rim, with no annuli, and core and rim compositions of the medium rare earth elements are the same throughout the population within crystals of differing size. Cr exhibits pronounced spiral zoning, and the average Cr content increases towards garnet rims. In all cases, spirals are centered on the geometric core of the crystals. These LA-ICP-MS maps highlight the complexity of garnet growth over a single prograde event, and indicate that there is still much to be learnt from the analysis of garnet using ever-improving analytical methods. We explore the potential causes of the variations in the distribution of trace elements in garnet, and assess how these zoning patterns may be used to refine our understanding of the intricacies of garnet crystallisation and the spatial and temporal degree of trace element equilibration during metamorphism.

  1. Contents of the JPL Distributed Active Archive Center (DAAC) archive, version 2-91

    NASA Technical Reports Server (NTRS)

    Smith, Elizabeth A. (Editor); Lassanyi, Ruby A. (Editor)

    1991-01-01

    The Distributed Active Archive Center (DAAC) archive at the Jet Propulsion Laboratory (JPL) includes satellite data sets for the ocean sciences and global change research to facilitate multidisciplinary use of satellite ocean data. Parameters include sea surface height, surface wind vector, sea surface temperature, atmospheric liquid water, and surface pigment concentration. The Jet Propulsion Laboratory DAAC is an element of the Earth Observing System Data and Information System (EOSDIS) and will be the United States distribution site for the Ocean Topography Experiment (TOPEX)/POSEIDON data and metadata.

  2. The effect of melt composition on the partitioning of trace elements between titanite and silicate melt

    NASA Astrophysics Data System (ADS)

    Prowatke, S.; Klemme, S.

    2003-04-01

    The aim of this study is to systematically investigate the influence of melt composition on the partitioning of trace elements between titanite and different silicate melts. Titanite was chosen because of its important role as an accessory mineral, particularly with regard to intermediate to silicic alkaline and calc-alkaline magmas [e.g. 1] and of its relative constant mineral composition over a wide range of bulk compositions. Experiments at atmospheric pressure were performed at temperatures between 1150°C and 1050°C. Bulk compositions were chosen to represent a basaltic andesite (SH3 - 53% SiO2), a dacite (SH2 - 65 SiO2) and a rhyolite (SH1 - 71% SiO2). Furthermore, two additional experimental series were conducted to investigate the effect of Al-Na and the Na-K ratio of melts on partitioning. Starting materials consisted of glasses that were doped with 23 trace elements including some selected rare earth elements (La, Ce, Pr, Sm, Gd, Lu), high field strength elements (Zr, Hf, Nb, Ta) and large ion lithophile elements (Cs, Rb, Ba) and Th and U. The experimental run products were analysed for trace elements using secondary ion mass spectrometry at Heidelberg University. Preliminary results indicate a strong effect of melt composition on trace element partition coefficients. Partition coefficients for rare-earth elements uniformly show a convex-upward shape [2, 3], since titanite accommodates the middle rare-earth elements more readily than the light rare-earth elements or the heavy rare-earth elements. Partition coefficients for the rare-earth elements follow a parabolic trend when plotted against ionic radius. The shape of the parabola is very similar for all studied bulk compositions, the position of the parabola, however, is strongly dependent on bulk composition. For example, isothermal rare-earth element partition coefficients (such as La) are incompatible (D<1) in alkali-rich silicate melts and strongly compatible (D>>1) in alkali-poor melt compositions. From our experimental data we present an model that combines the influence of the crystal lattice on partitioning with the effect of melt composition on trace element partition coefficients. [1] Nakada, S. (1991) Am. Mineral. 76: 548-560 [2] Green, T.H. and Pearson, N.J. (1986) Chem. Geol. 55: 105-119 [3] Tiepolo, M.; Oberti, R. and Vannucci, R. (2002) Chem. Geol. 191: 105-119

  3. Equilibrium distribution of rare earth elements between molten KCl-LiCl eutectic salt and liquid cadmium

    NASA Astrophysics Data System (ADS)

    Sakata, Masahiro; Kurata, Masaki; Hijikata, Takatoshi; Inoue, Tadashi

    1991-11-01

    Distribution experiments for several rare earth elements (La, Ce, Pr, Nd and Y) between molten KCl-LiCl eutectic salt and liquid Cd were carried out at 450, 500 and 600°C. The material balance of rare earth elements after reaching the equilibrium and their distribution and chemical states in a Cd sample frozen after the experiment were examined. The results suggested the formation of solid intermetallic compounds at the lower concentrations of rare earth metals dissolved in liquid Cd than those solubilities measured in the binary alloy system. The distribution coefficients of rare earth elements between two phases (mole fraction in the Cd phase divided by mole fraction in the salt phase) were determined at each temperature. These distribution coefficients were explained satisfactorily by using the activity coefficients of chlorides and metals in salt and Cd. Both the activity coefficients of metal and chloride caused a much smaller distribution coefficient of Y relative to those of other elements.

  4. Catalytic Graphitization of Coal-Based Carbon Materials with Light Rare Earth Elements.

    PubMed

    Wang, Rongyan; Lu, Guimin; Qiao, Wenming; Yu, Jianguo

    2016-08-30

    The catalytic graphitization mechanism of coal-based carbon materials with light rare earth elements was investigated using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, selected-area electron diffraction, and high-resolution transmission electron microscopy. The interface between light rare earth elements and carbon materials was carefully observed, and two routes of rare earth elements catalyzing the carbon materials were found: dissolution-precipitation and carbide formation-decomposition. These two simultaneous processes certainly accelerate the catalytic graphitization of carbon materials, and light rare earth elements exert significant influence on the microstructure and thermal conductivity of graphite. Moreover, by virtue of praseodymium (Pr), it was found that a highly crystallographic orientation of graphite was induced and formed, which was reasonably attributed to the similar arrangements of the planes perpendicular to (001) in both graphite and Pr crystals. The interface between Pr and carbon was found to be an important factor for the orientation of graphite structure.

  5. Rare Earth Extraction from NdFeB Magnet Using a Closed-Loop Acid Process.

    PubMed

    Kitagawa, Jiro; Uemura, Ryohei

    2017-08-14

    There is considerable interest in extraction of rare earth elements from NdFeB magnets to enable recycling of these elements. In practical extraction methods using wet processes, the acid waste solution discharge is a problem that must be resolved to reduce the environmental impact of the process. Here, we present an encouraging demonstration of rare earth element extraction from a NdFeB magnet using a closed-loop hydrochloric acid (HCl)-based process. The extraction method is based on corrosion of the magnet in a pretreatment stage and a subsequent ionic liquid technique for Fe extraction from the HCl solution. The rare earth elements are then precipitated using oxalic acid. Triple extraction has been conducted and the recovery ratio of the rare earth elements from the solution is approximately 50% for each extraction process, as compared to almost 100% recovery when using a one-shot extraction process without the ionic liquid but with sufficient oxalic acid. Despite its reduced extraction efficiency, the proposed method with its small number of procedures at almost room temperature is still highly advantageous in terms of both cost and environmental friendliness. This study represents an initial step towards realization of a closed-loop acid process for recycling of rare earth elements.

  6. Water Solubility in the Proto-Lunar Disk

    NASA Astrophysics Data System (ADS)

    Hauri, E. H.; Nakajima, M.

    2016-12-01

    The giant impact model is the scenario most widely accepted for the origin of the Moon, yet no satisfactory version of this model exists to explain the Earth-like H2O content of primitive lunar magmas. Here we investigate the likelihood that H2O from the Earth was transferred to the Moon in the aftermath of the giant impact. Nearly all variants of the giant impact model produce an energetic impact-generated debris disk that eventually coalesces to form the Moon [1]. Here we investigate the behavior of H2O in disks of Bulk Silicate Earth (BSE) composition produced by three impact scenarios; (a) the standard model of a Mars-sized impactor striking the proto-Earth [2]; (b) impact into a fast-spinning Earth [3]; and (c) impact of two sub-earths each being half the mass of the current Earth [4]. All of these models have been shown to be sufficiently energetic that, at maximum entropy and hydrostatic equilibrium following the impact, most of the mass of the proto-lunar disk consists of silicate melt and vapor, with vapor mass fractions ranging from 20-100% and mid-plane temperatures of 3500-6000K [1]. From these models, we calculate the 2D axisymmetric pressure structure of the disk, and calculate the solubility of H2O in liquid droplets that condense from the vapor atmosphere. Assuming a high bulk Earth H2O content of 1000 ppm, at the Roche radius and close to the disk midplane where pressures are highest (1 to 1000 bars), the mass fraction of all H-bearing species in the vapor is calculated to be ≤0.001, and the maximum H2O solubility in silicate melt is predicted to be <50 ppm because most of the water is dissociated at these high temperatures, in agreement with [5]. As the disk cools past the condensation of silicate vapor, the remaining vapor is dominated by Na and similarly volatile elements, with H2O a minor component of the vapor phase from 2500-1000K. The calculated vapor pressures are low at the midplane with strong vertical gradients, and thus calculated H2O solubility ranges widely, from <10 to 100s of ppm. The water content of forming moonlets is thus sensitive to the disk temperature where the moonlets form as the disk cools. [1] Nakajima & Stevenson (2014) Icarus 233:259-267. [2] Canup (2008) Icarus 196:518-538. [3] Cuk & Stewart (2012) Science 338:1047-1052. [4] Canup (2012) Science 338:1052-1055. [5] Pahlevan (2016) EPSL 445:104-113.

  7. Foam model of planetary formation

    NASA Astrophysics Data System (ADS)

    Andreev, Y.; Potashko, O.

    The Analysis of 2637 terrestrial minerals shows presence of characteristic element and isotope structure for each ore irrespective of its site. The model of processes geo-nuclear syntheses elements is offered due to avalanche merge of nucleus which simply explains these laws. Main assumption: nucleus, atoms, connections, ores and minerals were formed in volume of the modern Earth at an early stage of its evolution from uniform proto-substance. Substantive provisions of the model: 1)The most part of nucleus of atoms of all chemical elements of the Earth's crust were formed on the mechanism of avalanche chain merge practically in one stage (in geological scales) in a course of correlated(in scales of a planet) process with allocation of a plenty of heat. 2) Atoms of chemical elements were generated during cooling a planet with preservation of a relative spatial arrangement of nucleus. 3) Chemical compounds have arisen at cooling a surface of a planet and were accompanied by reorganizations (hashing) macro- and geo-scale. 4) Mineral formations are consequence of correlated behaviour of chemical compounds on microscopic scales during phase transition from gaseous or liquid to a firm condition. 5) Synthesis of chemical elements in deep layers of the Earth occurs till now. "Foaming'' instead of "Big Bang" The physical space is continual gas-fluid environment consist of super fluid foam. The continuity, keeping and uniqueness of proto-substance are postulated. Scenario: primary singularity-> droplets(proto-galaxies) droplets(proto-stars)-> droplets(proto-planets)-> droplets(proto- satellites)-> droplets. Proto-planet substance->proton+electron as 1st generation disintegration result of primary foam. Nuclei or nucleonic crystals are the 2nd generation in result of cascade merge of protons into conglomerates. The theory has applied to the analysis of samples of native copper deposit from Rafalovka's ore deposit in Ukraine. The abundance of elements by use of the roentgen fluorescent microanalysis has been made. Changes of a parity of elements are described by nuclear synthesis reactions: 16O+47Ti, 23Na+40Ca, 24Mg+39K, 31P+32S-> 63Cu; 16O+49Ti, 23Na+42Ca, 26Mg+39K, 31P+34S-> 65Cu Dramatical change of isotope parities of 56Fe and 57Fe in the sites of space carried on 3 millimetres. The content of 57Fe is greater then 56Fe in Cu granule.

  8. An assessment of exposure to rare earth elements among patients receiving long-term parenteral nutrition.

    PubMed

    Galusha, Aubrey L; Kruger, Pamela C; Howard, Lyn J; Parsons, Patrick J

    2018-05-01

    Patients receiving long-term parenteral nutrition (PN) are exposed to potentially toxic elements, which may accumulate in bone. Bone samples collected from seven PN patients (average = 14 years) and eighteen hip/knee samples were analyzed for Al as part of a previous investigation. Yttrium was serendipitously detected in the PN bone samples, leading to the present investigation of rare earth elements (REEs). A method for quantitating fifteen REEs in digested bone was developed based on tandem ICP-MS (ICP-MS/MS) to resolve spectral interferences. The method was validated against nine biological reference materials (RMs) for which assigned values were available for most REEs. Values found in two NIST bone SRMs (1400 Bone Ash and 1486 Bone Meal) compared favorably to those reported elsewhere. Method detection limits ranged from 0.9 ng g -1 (Tm) to 5.8 ng g -1 (Y). Median REE values in the PN patient group were at least fifteen times higher than the "control" group, and exceeded all previously reported data for eleven REEs in human bones. REE content in PN bones normalized to the Earth's upper crust revealed anomalies for Gd in two patients, likely from exposure to Gd-containing contrast agents used in MRI studies. A retrospective review of the medical record for one patient revealed an almost certain case of nephrogenic systemic fibrosis, associated with Gd exposure. Analysis of two current PN formulations showed traces of REEs with relative abundances similar to those found in the PN bones, providing convincing evidence that PN solutions were the primary source of REEs in this population. Copyright © 2018 Elsevier GmbH. All rights reserved.

  9. Petrogenesis of Early Cretaceous dioritic dikes in the Shanyang-Zhashui area, South Qinling, central China: Evidence for partial melting of thickened lower continental crust

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Yan, Zhen; Wang, Zongqi; Wang, Kunming

    2018-06-01

    The dioritic dikes distributed in the Shanyang-Zhashui area of the South Qinling region play an important role in understanding the deep magmatic processes and tectonic evolution during the orogenic process. The zircon Usbnd Pb ages of the dioritic dikes indicate that they were emplaced at ∼144 Ma and therefore postdate the dikes that formed in the intracontinental orogenic background after the continental collision between the North China Block (NCB) and the South China Block (SCB). The dioritic dikes have SiO2 contents of 56.86-64.93 wt%; K2O contents of 1.65-3.21 wt%; low MgO (1.50-2.66 wt%), Y (14.4-25.5 ppm) and heavy rare earth element (HREE) contents; low Mg# values (39.9-49); high Sr contents (528-4833 ppm); and high Sr/Y ratios (32.8-189). They exhibit highly fractionated REE and flat HREE patterns, strong enrichment in large ion lithophile elements (LILEs; e.g., Rb, Ba, and U) and depletion in high field strength elements (HFSEs) (e.g., Nb), as well as positive Sr and negative Ti anomalies. Furthermore, these dioritic dikes exhibit (87Sr/86Sr)i ratios ranging from 0.7048 to 0.7083, εNd(t) values ranging from -3.3 to -1.4, and εHf(t) values ranging from -4.1 to 1.6. The geochemical patterns of the dioritic dikes indicate that they possess adakitic characteristics. Moreover, the low MgO contents, Mg# values, Ni contents, Th/Ce ratios, and Srsbnd Ndsbnd Hf isotopic features all indicate that these dioritic dikes were generated by the partial melting of thickened mafic lower crust. The high La/Yb and Sr/Y ratios, low Y and Yb contents, absence of significant Eu anomalies, flat HREE patterns, and low Nb/Ta ratios of these rocks suggest that the adakitic melts were derived from the melting of garnet-bearing amphibolite. The geochronologic, elemental and isotopic evidence suggests that the dioritic dikes may have formed in a locally extensional environment within an overall N-S compressional setting or during the transition from compressional to extensional environments in the Early Cretaceous. This process resulted in the upwelling of the asthenospheric or lithospheric mantle, causing partial melting of the mafic lower crust and forming the adakitic dioritic melts.

  10. Petrography and geochemistry of the primary ore zone of the Kenticha rare metal granite-pegmatite field, Adola Belt, Southern Ethiopia: Implications for ore genesis and tectonic setting

    NASA Astrophysics Data System (ADS)

    Mohammedyasin, Mohammed Seid; Desta, Zerihun; Getaneh, Worash

    2017-10-01

    The aim of this work is to evaluate the genesis and tectonic setting of the Kenticha rare metal granite-pegmatite deposit using petrography and whole-rock geochemical analysis. The samples were analysed for major elements, and trace and rare earth elements by ICP-AES and ICP-MS, respectively. The Kenticha rare metal granite-pegmatite deposit is controlled by the N-S deep-seated normal fault that allow the emplacement of the granite-pegmatite in the study area. Six main mineral assemblages have been identified: (a) alaskitic granite (quartz + microcline + albite with subordinate muscovite), (b) aplitic layer (quartz + albite), (c) muscovite-quartz-microcline-albite pegmatite, (d) spodumene-microcline-albite pegmatite, partly albitized or greisenized, (e) microcline-albite-green and pink spodumene pegmatite with quartz-microcline block, which is partly albitized and greisenized, and (f) quartz core. This mineralogical zonation is also accompanied by variation in Ta ore concentration and trace and rare earth elements content. The Kenticha granite-pegmatite is strongly differentiated with high SiO2 (72-84 wt %) and enriched with Rb (∼689 ppm), Be (∼196 ppm), Nb (∼129 ppm), Ta (∼92 ppm) and Cs (∼150 ppm) and depleted in Ba and Sr. The rare earth element (REE) patterns of the primary ore zone (below 60 m depth) shows moderate enrichment in light REE ((La/Yb)N = ∼8, and LREE/HREE = ∼9.96) and negative Eu-anomaly (Eu/Eu* = ∼0.4). The whole-rock geochemical data display the Within Plate Granite (WPG) and syn-Collisional Granite (syn-COLG) suites and interpret as its formation is crustal related melting. The mineralogical assemblage, tectonic setting and geochemical signatures implies that the Kenticha rare metal bearing granite pegmatite is formed by partial melting of metasedimentary rocks during post-Gondwana assembly and further tantalite enrichment through later hydrothermal-metasomatic processes.

  11. SHRIMP U-Pb ages of xenotime and monazite from the Spar Lake red bed-associated Cu-Ag deposit, western Montana: Implications for ore genesis

    USGS Publications Warehouse

    Aleinikoff, John N.; Hayes, Timothy S.; Evans, Karl V.; Mazdab, Frank K.; Pillers, Renee M.; Fanning, C. Mark

    2012-01-01

    Xenotime occurs as epitaxial overgrowths on detrital zircons in the Mesoproterozoic Revett Formation (Belt Supergroup) at the Spar Lake red bed-associated Cu-Ag deposit, western Montana. The deposit formed during diagenesis of Revett strata, where oxidizing metal-bearing hydrothermal fluids encountered a reducing zone. Samples for geochronology were collected from several mineral zones. Xenotime overgrowths (1–30 μm wide) were found in polished thin sections from five ore and near-ore zones (chalcocite-chlorite, bornite-calcite, galena-calcite, chalcopyrite-ankerite, and pyrite-calcite), but not in more distant zones across the region. Thirty-two in situ SHRIMP U-Pb analyses on xenotime overgrowths yield a weighted average of 207Pb/206Pb ages of 1409 ± 8 Ma, interpreted as the time of mineralization. This age is about 40 to 60 m.y. after deposition of the Revett Formation. Six other xenotime overgrowths formed during a younger event at 1304 ± 19 Ma. Several isolated grains of xenotime have 207Pb/206Pb ages in the range of 1.67 to 1.51 Ga, and thus are considered detrital in origin. Trace element data can distinguish Spar Lake xenotimes of different origins. Based on in situ SHRIMP analysis, detrital xenotime has heavy rare earth elements-enriched patterns similar to those of igneous xenotime, whereas xenotime overgrowths of inferred hydrothermal origin have hump-shaped (i.e., middle rare earth elements-enriched) patterns. The two ages of hydrothermal xenotime can be distinguished by slightly different rare earth elements patterns. In addition, 1409 Ma xenotime overgrowths have higher Eu and Gd contents than the 1304 Ma overgrowths. Most xenotime overgrowths from the Spar Lake deposit have elevated As concentrations, further suggesting a genetic relationship between the xenotime formation and Cu-Ag mineralization.

  12. Geochemical behavior of rare earth elements of the hydrothermal alterations within the Tepeoba porphyry Cu-Mo-Au deposits at Balikesir, NW Turkey

    NASA Astrophysics Data System (ADS)

    Doner, Zeynep; Abdelnasser, Amr; Kiran Yildirim, Demet; Kumral, Mustafa

    2016-04-01

    This work reports the geochemical characteristics and behavior of the rare earth elements (REE) of the hydrothermal alteration of the Tepeoba porphyry Cu-Mo-Au deposit located in the Anatolian tectonic belt at Biga peninsula (Locally Balikesir province), NW Turkey. The Cu-Mo-Au mineralization at this deposit hosted in the hornfels rocks and related to the silicic to intermediate intrusion of Eybek pluton. It locally formed with brecciated zones and quartz vein stockworks, as well as the brittle fracture zones associated with intense hydrothermal alteration. Three main alteration zones with gradual boundaries formed in the mine area in the hornfels rock that represents the host rock, along that contact the Eybek pluton; potassic, propylitic and phyllic alteration zones. The potassic alteration zone that formed at the center having high amount of Cu-sulfide minerals contains biotite, muscovite, and sericite with less amount of K-feldspar and associated with tourmalinization alteration. The propylitic alteration surrounds the potassic alteration having high amount of Mo and Au and contains chlorite, albite, epidote, calcite and pyrite. The phyllic alteration zone also surrounds the potassic alteration containing quartz, sericite and pyrite minerals. Based on the REE characteristics and content and when we correlate the Alteration index (AI) with the light REEs and heavy REEs of each alteration zone, it concluded that the light REEs decrease and heavy REEs increase during the alteration processes. The relationships between K2O index with Eu/Eu* and Sr/Sr* reveals a positive correlation in the potassic and phyllic alteration zones and a negative correlation in the propylitic alteration zone. This refers to the hydrothermal solution which is responsible for the studied porphyry deposits and associated potassic and phyllic alterations has a positive Eu and Sr anomaly as well as these elements were added to the altered rock from the hydrothermal solution. Keywords: Rare earth elements geochemistry; Tepeoba porphyry Cu-Mo-Au deposits; Balikesir; Turkey

  13. Metal-Silicate-Sulfide Partitioning of U, Th, and K: Implications for the Budget of Volatile Elements in Mercury

    NASA Technical Reports Server (NTRS)

    Habermann, M.; Boujibar, A.; Righter, K.; Danielson, L.; Rapp, J.; Righter, M.; Pando, K.; Ross, D. K.; Andreasen, R.

    2016-01-01

    During formation of the solar system, the Sun produced strong solar winds, which stripped away a portion of the volatile elements from the forming planets. Hence, it was expected that planets closest to the sun, such as Mercury, are more depleted in volatile elements in comparison to other terrestrial planets. However, the MESSENGER mission detected higher than expected K/U and K/Th ratios on Mercury's surface, indicating a volatile content between that of Mars and Earth. Our experiments aim to resolve this discrepancy by experimentally determining the partition coefficients (D(sup met/sil)) of K, U, and Th between metal and silicate at varying pressure (1 to 5 GPa), temperature (1500 to 1900 C), oxygen fugacity (IW-2.5 to IW-6.5) and sulfur-content in the metal (0 to 33 wt%). Our data show that U, Th, and K become more siderophile with decreasing fO2 and increasing sulfur-content, with a stronger effect for U and Th in comparison to K. Using these results, the concentrations of U, Th, and K in the bulk planet were calculated for different scenarios, where the planet equilibrated at a fO2 between IW-4 and IW-7, assuming the existence of a FeS layer, between the core and mantle, with variable thickness. These models show that significant amounts of U and Th are partitioned into Mercury's core. The elevated superficial K/U and K/Th values are therefore only a consequence of the sequestration of U and Th into the core, not evidence of the overall volatile content of Mercury.

  14. Analysis of some metallic elements and metalloids composition and relationships in parasol mushroom Macrolepiota procera.

    PubMed

    Falandysz, Jerzy; Sapkota, Atindra; Dryżałowska, Anna; Mędyk, Małgorzata; Feng, Xinbin

    2017-06-01

    The aim of the study was to characterise the multi-elemental composition and associations between a group of 32 elements and 16 rare earth elements collected by mycelium from growing substrates and accumulated in fruiting bodies of Macrolepiota procera from 16 sites from the lowland areas of Poland. The elements were quantified by inductively coupled plasma quadrupole mass spectrometry using validated method. The correlation matrix obtained from a possible 48 × 16 data matrix has been used to examine if any association exits between 48 elements in mushrooms foraged from 16 sampling localizations by multivariate approach using principal component (PC) analysis. The model could explain up to 93% variability by eight factors for which an eigenvalue value was ≥1. Absolute values of the correlation coefficient were above 0.72 (significance at p < 0.05) for 43 elements. From a point of view by consumer, the absolute content of Cd, Hg, Pb in caps of M. procera collected from background (unpolluted) areas could be considered elevated while sporadic/occasional ingestion of this mushroom is considered safe. The multivariate functional analysis revealed on associated accumulation of many elements in this mushroom. M. procera seem to possess some features of a bio-indicative species for anthropogenic Pb but also for some geogenic metals.

  15. Analysis of rare earth elements in coal fly ash using laser ablation inductively coupled plasma mass spectrometry and scanning electron microscopy

    NASA Astrophysics Data System (ADS)

    Thompson, Robert L.; Bank, Tracy; Montross, Scott; Roth, Elliot; Howard, Bret; Verba, Circe; Granite, Evan

    2018-05-01

    Reference standard NIST SRM 1633b and FA 345, a fly ash sample from an eastern U.S. coal power plant, were analyzed to determine and quantify the mineralogical association of rare earth elements (REE). These analyses were completed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and a scanning electron microscope, equipped with an energy-dispersive X-ray spectrometer (SEM-EDS). Internal standardization was avoided by quantifying elemental concentrations by normalizing to 100% oxides. Mineral grains containing elevated REE concentrations were found in diverse chemical environments, but were most commonly found in regions where Al and Si were predominant. Dividing the spot analyses into time segments yielded plots that showed the REE content changing over time as individual mineral grains were being ablated. SEM-EDS images of FA 345 confirmed the trends that were found in the LA-ICP-MS results. Small grains of apatite, monazite, or zircon were frequently observed as free mineral grains or embedded in amorphous aluminosilicate glass and were not associated with ferrous particles. This finding is consistent with previous reports that magnetic enrichment may be an effective way of concentrating non-magnetic REE phases. Furthermore, aggressive mechanical and chemical-based separation schemes will be required to separate and recover REE from aluminosilicate glass.

  16. Architectures Toward Reusable Science Data Systems

    NASA Astrophysics Data System (ADS)

    Moses, J. F.

    2014-12-01

    Science Data Systems (SDS) comprise an important class of data processing systems that support product generation from remote sensors and in-situ observations. These systems enable research into new science data products, replication of experiments and verification of results. NASA has been building ground systems for satellite data processing since the first Earth observing satellites launched and is continuing development of systems to support NASA science research, NOAA's weather satellites and USGS's Earth observing satellite operations. The basic data processing workflows and scenarios continue to be valid for remote sensor observations research as well as for the complex multi-instrument operational satellite data systems being built today. System functions such as ingest, product generation and distribution need to be configured and performed in a consistent and repeatable way with an emphasis on scalability. This paper will examine the key architectural elements of several NASA satellite data processing systems currently in operation and under development that make them suitable for scaling and reuse. Examples of architectural elements that have become attractive include virtual machine environments, standard data product formats, metadata content and file naming, workflow and job management frameworks, data acquisition, search, and distribution protocols. By highlighting key elements and implementation experience the goal is to recognize architectures that will outlast their original application and be readily adaptable for new applications. Concepts and principles are explored that lead to sound guidance for SDS developers and strategists.

  17. Architectures Toward Reusable Science Data Systems

    NASA Technical Reports Server (NTRS)

    Moses, John

    2015-01-01

    Science Data Systems (SDS) comprise an important class of data processing systems that support product generation from remote sensors and in-situ observations. These systems enable research into new science data products, replication of experiments and verification of results. NASA has been building systems for satellite data processing since the first Earth observing satellites launched and is continuing development of systems to support NASA science research and NOAAs Earth observing satellite operations. The basic data processing workflows and scenarios continue to be valid for remote sensor observations research as well as for the complex multi-instrument operational satellite data systems being built today. System functions such as ingest, product generation and distribution need to be configured and performed in a consistent and repeatable way with an emphasis on scalability. This paper will examine the key architectural elements of several NASA satellite data processing systems currently in operation and under development that make them suitable for scaling and reuse. Examples of architectural elements that have become attractive include virtual machine environments, standard data product formats, metadata content and file naming, workflow and job management frameworks, data acquisition, search, and distribution protocols. By highlighting key elements and implementation experience we expect to find architectures that will outlast their original application and be readily adaptable for new applications. Concepts and principles are explored that lead to sound guidance for SDS developers and strategists.

  18. Experimental Parameters Affecting Stripping of Rare Earth Elements from Loaded Sorptive Media in Simulated Geothermal Brines

    DOE Data Explorer

    Dean Stull

    2016-05-24

    Experimental results from several studies exploring the impact of pH and acid volume on the stripping of rare earth elements (REEs) loaded onto ligand-based media via an active column. The REEs in this experiment were loaded onto the media through exposure to a simulated geothermal brine with known mineral concentrations. The data include the experiment results, rare earth element concentrations, and the experimental parameters varied.

  19. [Distribution characteristic and current situation of soil rare earth contamination in the Bayan Obo mining area and Baotou tailing reservoir in Inner Mongolia].

    PubMed

    Guo, Wei; Fu, Rui-ying; Zhao, Ren-xin; Zhao, Wen-jing; Guo, Jiang-yuan; Zhang, Jun

    2013-05-01

    The pollution status and distribution characteristic of rare earth elements in soil were analyzed around Bayan Obo mining area and Baotou tailing reservoir located in Inner Mongolia grassland ecosystem, aiming at grasping the overall situation of grassland ecosystem pollution caused by rare earth elements and providing basic information as well as theoretical basis. The results indicated that seven rare earth elements in soils from different directions of Baotou tailing reservoir accumulated to a certain extent compared to the soil background value of Inner Mongolia. The pollution degree was Ce > La > Nd > Pr > Sm > Y > Eu. Within 50 m from the edge of tailing reservoir, soil rare earth contamination was the most serious, with the concentrations of La, Ce, Pr, Nd, Sm, Eu and Y reaching 11,45.0 mg x kg(-1), 23,636.0 mg x kg(-1), 4568.16 mg x kg(-1) , 6855.51 mg x kg(-1), 582.18 mg x kg(-1), 94.21 mg x kg(-1)), and 136.25 mg x kg(-1), respectively. Owing to the dominant wind direction of northwest, soils from the southeast were contaminated most seriously. For Bayan Obo mining area, the concentrations of seven rare earth elements in soil from the mining area were significantly higher than those of other areas investigated, with the concentrations of La, Ce, Pr, Nd, Sm, Eu and Y reaching 3112.56 mg x kg(-1), 7142.12 mg x kg(-1), 1467.12 mg x kg(-1), 2552.80 mg x kg(-1), 210.80 mg x kg(-1), 36.20 mg x kg(-1) and 63.22 mg x kg(-1), respectively. The soils of six areas of Bayan Obo mining area were all contaminated by rare earth elements, and the contamination degree was in the order of mining area > outside the dump > east side of the railway > the dump > outside the urban area > west side of the railway. Besides, the transportation of rare earth ore led to the soil rare earth contamination along the railway, and the distribution characteristic of rare earth elements in soils along the railway was affected by the dominant wind direction of northwest. Baotou tailing reservoir and Bayan Obo mining area had the same contamination characteristic, and the concentrations of rare earth elements were in accordance with those in the tailings. The health and stabilization of local grassland ecosystem are being threatened by excessive soil rare earth elements.

  20. Ground-state properties of rare-earth metals: an evaluation of density-functional theory.

    PubMed

    Söderlind, Per; Turchi, P E A; Landa, A; Lordi, V

    2014-10-15

    The rare-earth metals have important technological applications due to their magnetic properties, but are scarce and expensive. Development of high-performance magnetic materials with less rare-earth content is desired, but theoretical modeling is hampered by complexities of the rare earths electronic structure. The existence of correlated (atomic-like) 4f electrons in the vicinity of the valence band makes any first-principles theory challenging. Here, we apply and evaluate the efficacy of density-functional theory for the series of lanthanides (rare earths), investigating the influence of the electron exchange and correlation functional, spin-orbit interaction, and orbital polarization. As a reference, the results are compared with those of the so-called 'standard model' of the lanthanides in which electrons are constrained to occupy 4f core states with no hybridization with the valence electrons. Some comparisons are also made with models designed for strong electron correlations. Our results suggest that spin-orbit coupling and orbital polarization are important, particularly for the magnitude of the magnetic moments, and that calculated equilibrium volumes, bulk moduli, and magnetic moments show correct trends overall. However, the precision of the calculated properties is not at the level of that found for simpler metals in the Periodic Table of Elements, and the electronic structures do not accurately reproduce x-ray photoemission spectra.

  1. Earth, Air, Fire and Water in Our Elements

    ERIC Educational Resources Information Center

    Lievesley, Tara

    2007-01-01

    The idea that everything is made of the four "elements", earth, air, fire and water, goes back to the ancient Greeks. In this article, the author talks about the origins of ideas about the elements. The author provides an account that attempts to summarise thousands of years of theoretical development of the elements in a thousand words or so.

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

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  3. Chondritic late accretion to Mars and the nature of shergottite reservoirs

    NASA Astrophysics Data System (ADS)

    Tait, Kim T.; Day, James M. D.

    2018-07-01

    Mars is considered to have formed as a planetary embryo that experienced extensive differentiation early in its history. Shergottite meteorites preserve evidence for this history, and for late accretion events that affected their mantle sources within Mars. Here we report the first coupled 187Re-187Os, 87Sr/86Sr, highly siderophile element (HSE: Os, Ir, Ru, Pt, Pd, Re) and major element abundance dataset for martian shergottites that span a range of MgO contents, from 6.4 to 30.3 wt.%. The shergottites range from picro-basalt to basaltic-andesite compositions, have enriched to depleted incompatible trace-element compositions, and define fractional crystallization trends, enabling the determination of HSE compatibility for martian magmatism in the order: Os > Ir ≥ Ru ≫ Pt ≥ Pd ≥ Re. This order of compatibility is like that defined previously for Earth and the Moon, but the fractionation of strongly compatible Os, Ir and Ru appears to take place at higher MgO contents in martian magmas, due to early onset of sulfide fractionation. In general, enriched shergottites have lower MgO contents than intermediate or depleted shergottites and have fractionated HSE patterns (Re + Pd + Pt > Ru + Ir + Os) and more radiogenic measured 87Sr/86Sr (0.7127-0.7235) and 187Os/188Os (0.140-0.247) than intermediate or depleted shergottite meteorites (87Sr/86Sr = 0.7010-0.7132; 187Os/188Os = 0.127-0.141). Osmium isotope compositions, corrected for crystallization age, define compositions that are implausibly unradiogenic in some enriched shergottites, implying recent mobilization of Re in some samples. Filtering for the effects of alteration and high Re/Os through crystal-liquid fractionation leads to a positive correlation between age-corrected Sr and Os isotope compositions. Mixing between hypothetical martian crustal and mantle reservoirs are unable to generate the observed Sr-Os isotope compositions of shergottites, which require either distinct and discrete long-term incompatible-element depleted and enriched mantle sources, or originate from hybridized melting of deep melts with metasomatized martian lithosphere. Using MgO-regression methods, we obtain a modified estimate of the bulk silicate Mars HSE composition of (in ng g-1) 0.4 [Re], 7.4 [Pd], 9.6 [Pt], 6.2 [Ru], 3.7 [Ir], 4 [Os], and a long-term chondritic 187Os/188Os ratio (∼0.1312). This result does not permit existing models invoking high-pressure and temperature partitioning of the HSE. Instead, our estimate implies 0.6-0.7% by mass of late accretion of broadly chondritic material to Mars. Our results indicate that Mars could have accreted earlier than Earth, but that disproportional accretion of large bodies and a relative constant flux of accretion of available materials in the first 50-100 Ma of Solar System led to the broad similarity in HSE abundances between Earth and Mars.

  4. Production method for making rare earth compounds

    DOEpatents

    McCallum, R.W.; Ellis, T.W.; Dennis, K.W.; Hofer, R.J.; Branagan, D.J.

    1997-11-25

    A method of making a rare earth compound, such as a earth-transition metal permanent magnet compound, without the need for producing rare earth metal as a process step, comprises carbothermically reacting a rare earth oxide to form a rare earth carbide and heating the rare earth carbide, a compound-forming reactant (e.g., a transition metal and optional boron), and a carbide-forming element (e.g., a refractory metal) that forms a carbide that is more thermodynamically favorable than the rare earth carbide whereby the rare earth compound (e.g., Nd{sub 2}Fe{sub 14}B or LaNi{sub 5}) and a carbide of the carbide-forming element are formed.

  5. Production method for making rare earth compounds

    DOEpatents

    McCallum, R. William; Ellis, Timothy W.; Dennis, Kevin W.; Hofer, Robert J.; Branagan, Daniel J.

    1997-11-25

    A method of making a rare earth compound, such as a earth-transition metal permanent magnet compound, without the need for producing rare earth metal as a process step, comprises carbothermically reacting a rare earth oxide to form a rare earth carbide and heating the rare earth carbide, a compound-forming reactant (e.g. a transition metal and optional boron), and a carbide-forming element (e.g. a refractory metal) that forms a carbide that is more thermodynamically favorable than the rare earth carbide whereby the rare earth compound (e.g. Nd.sub.2 Fe.sub.14 B or LaNi.sub.5) and a carbide of the carbide-forming element are formed.

  6. Partitioning of Mo, P and other siderophile elements (Cu, Ga, Sn, Ni, Co, Cr, Mn, V, and W) between metal and silicate melt as a function of temperature and silicate melt composition

    NASA Astrophysics Data System (ADS)

    Righter, K.; Pando, K. M.; Danielson, L.; Lee, Cin-Ty

    2010-03-01

    Metal-silicate partition coefficients can provide information about the earliest differentiation histories of terrestrial planets and asteroids. Systematic studies of the effects of key parameters such as temperature and melt composition are lacking for many elements. In particular, data for Mo is scarce, but given its refractory nature, is of great value in interpreting metal-silicate equilibrium. Two series of experiments have been carried out to study Mo and P partitioning between Fe metallic liquid and basaltic to peridotitic silicate melt, at 1 GPa and temperatures between 1500 and 1900 °C. Because the silicate melt utilized was natural basalt, there are also measurable quantities of 9 other siderophile elements (Ni, Co, W, Sn, Cu, Mn, V, Cr, Ga and Zn). The Ni and Co data can be used to assess consistency with previous studies. In addition, the new data also allow a first systematic look at the temperature dependence of Cu, Ga, Sn, Cr, Mn V and W for basaltic to peridotitic melts. Many elements exhibit an increase in siderophile behavior at higher temperature, contrary to popular belief, but consistent with predictions from thermodynamics. Using these new data we examine DMomet/sil and DPmet/sil in detail and show that increasing temperature causes a decrease in the former and an increase in the latter, whereas both increase with MgO content of the silicate melt. The depletions of Mo and P in the mantle of the Earth can be explained by metal-silicate equilibrium at magma ocean conditions — both elements are satisfied at PT conditions of an intermediate depth magma ocean for the Earth 22.5 GPa and 2400 °C.

  7. Diatremes of the Hopi Buttes, Arizona; chemical and statistical analyses

    USGS Publications Warehouse

    Wenrich, K.J.; Mascarenas, J.F.

    1982-01-01

    Lacustrine sediments deposited in maar lakes of the Hopi Buttes diatremes are hosts for uranium mineralization of as much as 1500 ppm. The monchiquites and limburgite turfs erupted from the diatremes are distinguished from normal alkalic basalts of the Colorado Plateau by their extreme silica undersaturation and high water, TiO2, and P2O5 contents. Many trace elements are also unusually abundant, including Ag, As, Ba, Be, Ce, Dy, Eu, F, Gd, Hf, La, Nd, Pb, Rb, Se, Sm, Sn, Sr, Ta, Tb, Th, U, V, Zn, and Zr. The lacustrine sediments, which consist predominantly of travertine and clastic rocks, are the hosts for syngenetic and epigenetic uranium mineralization of as much as 1500 ppm uranium. Fission track maps show the uranium to be disseminated within the travertine and clastic rocks, and although microprobe analyses have not, as yet, revealed discrete uranium-bearing phases, the clastic rocks show a correlation of high Fe, Ti, and P with areas of high U. Correlation coefficients show that for the travertines, clastics, and limburgite ruffs, Mo, As, Sr, Co, and V appear to have the most consistent and strongest correlations with uranium. Many elements, including many of the rare-earth elements, that are high in these three rocks are also high in the monchiquites, as compared to the average crustal abundance for the respective rock type. This similar suite of anomalous elements, which includes such immobile elements as the rare earths, suggests that Fluids which deposited the travertines were related to the monchiquitic magma. The similar age of about 5 m.y. for both the lake beds and the monchiquites also appears to support this source for the mineralizing fluids.

  8. Extraction of rare earth elements from low-grade Bauxite via precipitation reaction

    NASA Astrophysics Data System (ADS)

    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.

  9. In-situ measurements of rare earth elements in deep sea sediments using nuclear methods.

    PubMed

    Obhođaš, Jasmina; Sudac, Davorin; Meric, Ilker; Pettersen, Helge E S; Uroić, Milivoj; Nađ, Karlo; Valković, Vlado

    2018-03-21

    The prospecting activities for finding new rare earth elements (REE) sources have increased greatly in recent years. One of the main discoveries was announced in 2011 by Japanese researchers who found large quantities of REE on the ocean seafloor at the sea depths greater than 4,000 m. The classic approach to investigate REE in deep sea sediments is to obtain sediment samples by drilling that is followed by laborious laboratory analysis. This is very expensive, time consuming and not appropriate for exploring vast areas. In order to efficiently explore the ocean floor for REE deposits, the further development of affordable sensors is needed. Here, we propose two nuclear techniques for exploring REE in surface deep sea sediments: i) Passive measurement of lutetium-176 radioactivity, appropriate if long-term in-situ measurements are possible, and ii) The use of the neutron sensor attached to a remotely operated vehicle for rapid in-situ measurement of gadolinium by thermal neutron-capture. Since concentrations of lutetium and gadolinium show strong linear correlation to the total REE concentrations in deep sea sediments, it is possible to deduce the total REE content by measuring Lu or Gd concentrations only.

  10. Chaotic....!! Active and Engaged. Effects of an active learning classroom on student retention and engagement.

    NASA Astrophysics Data System (ADS)

    Palsole, S.; Serpa, L. F.

    2014-12-01

    Scientific literacy has been defined as the foremost challenge of this decade (AAAS, 2012). The Geological Society of American in its position statement postis that due to the systemic nature of the discipline of earth science, it is the most effective way to engage students in STEM disciplines. Given that the most common place for exposure to earth sciences is at the freshman level for non majors, we decided to transform a freshman introductory geology course to an active, student centered course, using an inquiry based approach. Our focus was to ensure the students saw the earth sciences as broadly applicative field, and not an esoteric science. To achieve this goal, we developed a series of problems that required the students to apply the concepts acquired through their self guided learning into the different topics of the course. This self guided learning took the form of didactic content uploaded into the learning management system (the various elements used to deliver the content were designed video clips, short text based lectures, short formative assessments, discussion boards and other web based discovery exercises) with the class time devoted to problem solving. A comparison of student performance in the active learning classroom vs. a traditional classroom as measured on a geoscience concept inventory (the questions were chosen by a third party who was not teaching either courses) showed that the the students in the active learning classroom scored 10% higher on the average in comparison to the traditional class. In addition to this heightened performance, the students in the active classroom also showed a higher degree of content retention 8 weeks after the semester had ended. This session will share the design process, some exercises and efficacy data collected.

  11. Electro-kinetic Separation of Rare Earth Elements Using a Redox-Active Ligand.

    PubMed

    Fang, Huayi; Cole, Bren E; Qiao, Yusen; Bogart, Justin A; Cheisson, Thibault; Manor, Brian C; Carroll, Patrick J; Schelter, Eric J

    2017-10-16

    Purification of rare earth elements is challenging due to their chemical similarities. All of the deployed separation methods rely on thermodynamic properties, such as distribution equilibria in solvent extraction. Rare-earth-metal separations based on kinetic differences have not been examined. Herein, we demonstrate a new approach for rare-earth-element separations by exploiting differences in the oxidation rates within a series of rare earth compounds containing the redox-active ligand [{2-(tBuN(O))C 6 H 4 CH 2 } 3 N] 3- . Using this method, a single-step separation factor up to 261 was obtained for the separation of a 50:50 yttrium-lutetium mixture. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Fast preconcentration of trace rare earth elements from environmental samples by di(2-ethylhexyl)phosphoric acid grafted magnetic nanoparticles followed by inductively coupled plasma mass spectrometry detection

    NASA Astrophysics Data System (ADS)

    Yan, Ping; He, Man; Chen, Beibei; Hu, Bin

    2017-10-01

    In this work, di(2-ethylhexyl)phosphoric acid (P204) grafted magnetic nanoparticles were synthesized by fabricating P204 onto Fe3O4@TiO2 nanoparticles based on Lewis acid-base interaction between Ti and phosphate group under weakly acidic condition. The prepared Fe3O4@TiO2@P204 nanoparticles exhibited excellent selectivity for rare earth elements, and good anti-interference ability. Based on it, a method of magnetic solid phase extraction (MSPE) combined with inductively coupled plasma mass spectrometry (ICP-MS) was developed for fast preconcentration and determination of trace rare earth elements in environmental samples. Under the optimal conditions, the detection limits of rare earth elements were in the range of 0.01 (Tm)-0.12 (Nd) ng L- 1 with an enrichment factor of 100-fold, and the relative standard deviations ranged from 4.9 (Pr) to 10.7% (Er). The proposed method was successfully applied to the determination of rare earth elements in environmental samples, including river water, lake water, seawater and sediment.

  13. Olivine inclusions in Siberian diamonds and mantle xenoliths: Contrasting water and trace-element contents

    NASA Astrophysics Data System (ADS)

    Jean, M. M.; Taylor, L. A.; Howarth, G. H.; Peslier, A. H.; Fedele, L.; Bodnar, R. J.; Guan, Y.; Doucet, L. S.; Ionov, D. A.; Logvinova, A. M.; Golovin, A. V.; Sobolev, N. V.

    2016-11-01

    A subject of continuing debate is how the Earth's lithospheric portion of the upper mantle has remained the thickest (> 200 km) and oldest (> 3 Gy) beneath cratons and is yet surrounded by a vigorously convecting asthenosphere. It is generally admitted that water is a key parameter in the strength and longevity of cratonic roots, because olivine, the main phase of the lithospheric mantle, becomes stronger if its water content decreases. Expanding upon the work presented in Novella et al. (2015) and Taylor et al. (2016), we report new water contents for additional olivine inclusions in diamonds together with the trace-element composition for all olivine inclusions, as well as for mantle xenoliths from various kimberlite pipes located on the Siberian craton. The olivine diamond inclusions from this study have systematically low-water contents (< 50 ppmw H2O), moderate to high forsterite (e.g., Fo91-94) contents and low Ni, Co, and Zn ppm contents (e.g., < 2848, < 108, and < 47 ppm, respectively). In contrast, olivines from Siberian craton mantle xenoliths have a wide range of water contents (6-323 ppmw H2O) and extend to lower-Fo (91-92), Ni, Co, and Zn-rich compositions, compared to the diamond inclusions. Depleted incompatible trace-element concentrations in olivine (0.1-0.001 × Primitive Mantle) advance our hypothesis for the protogenetic origins for the majority of Siberian diamond inclusions. These observations are consistent with the peridotite xenoliths as representing a part of the cratonic lithosphere that has experienced melt re-fertilization, which has also transported water. The olivine diamond inclusions, on the other hand, preserve "micro-samples" of an initial, dry cratonic lithosphere, mostly resulting from melting events. These inclusions are likely sourced from the initial cratonic mantle lithosphere, which thereby, resisted delamination over time, due to its buoyancy and strength, imparted from melt and water depletion, respectively. And thus, our data provides a major argument that the kimberlite-hosted mantle xenoliths may be more metasomatized than common rocks at the base of the Siberian and other cratonic roots away from kimberlite fields.

  14. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Selle, J E

    Attempts were made to apply the Kaufman method of calculating binary phase diagrams to the calculation of binary phase diagrams between the rare earths, actinides, and the refractory transition metals. Difficulties were encountered in applying the method to the rare earths and actinides, and modifications were necessary to provide accurate representation of known diagrams. To calculate the interaction parameters for rare earth-rare earth diagrams, it was necessary to use the atomic volumes for each of the phases: liquid, body-centered cubic, hexagonal close-packed, and face-centered cubic. Determination of the atomic volumes of each of these phases for each element is discussedmore » in detail. In some cases, empirical means were necessary. Results are presented on the calculation of rare earth-rare earth, rare earth-actinide, and actinide-actinide diagrams. For rare earth-refractory transition metal diagrams and actinide-refractory transition metal diagrams, empirical means were required to develop values for the enthalpy of vaporization for rare earth elements and values for the constant (C) required when intermediate phases are present. Results of using the values determined for each element are presented.« less

  15. Critical Zone Weathering and Your Smartphone: Understanding How Mineral Decomposition and Colloid Redistribution Can Generate Rare Earth Element Deposits

    NASA Astrophysics Data System (ADS)

    Bern, C.; Foley, N.

    2014-12-01

    Rare earth elements (REE's) are crucial in the manufacture of smartphones and many other high tech devices. Increasing global demand and relatively narrow geographic sourcing have promoted interest in understanding REE deposit genesis and distribution. Highly weathered, clay-hosted, ion-exchange type deposits in southern China are the source of much of the world's production of the more valuable heavy REEs. Such deposits form as REE-bearing minerals weather and REEs released to solution in ionic form are retained by negatively charged exchange sites on clay minerals. We are investigating the potential for ion-exchange REE deposits in the Piedmont of the southeastern United States, where slow erosion rates have preserved thick (up to 20 m) regolith, as required for such deposits. The Liberty Hill pluton outcrops as coarse-grained biotite-amphibole granite and quartz monzonite over nearly 400 km2 in South Carolina, and has an age of 305 Ma (new SHRIMP ion microprobe zircon age). In weathered profiles over the pluton, ion-exchangeable REE content ranges from 8 to 580 ppm and accounts for 2 to 80% of bulk REE content. Elemental and heavy mineral distributions suggest the wide ranging differences in leachability may be attributable to the amount and distribution of resistant REE-bearing phases (e.g., monazite) relative to more easily weathered phases (e.g., allanite) in the parent granite. The REEs show little mobility within the regolith, indicating the effectiveness of the ion-exchange retention mechanism. In contrast, vertical redistribution of colloidal material shows maximum accumulations at ~1 m depth, as traced by the newly developed dual-phase (colloids vs. solution) mass balance model. The contrast suggests redistributed colloidal material has minimal influence on REE mobilization or retention. Conditions and processes necessary for ion-exchange REE deposit development exist in the Piedmont, but their presence will depend upon favorable parent rock mineralogy.

  16. A nucleosynthetic origin for the Earth's anomalous (142)Nd composition.

    PubMed

    Burkhardt, C; Borg, L E; Brennecka, G A; Shollenberger, Q R; Dauphas, N; Kleine, T

    2016-09-15

    A long-standing paradigm assumes that the chemical and isotopic compositions of many elements in the bulk silicate Earth are the same as in chondrites. However, the accessible Earth has a greater (142)Nd/(144)Nd ratio than do chondrites. Because (142)Nd is the decay product of the now-extinct (146)Sm (which has a half-life of 103 million years), this (142)Nd difference seems to require a higher-than-chondritic Sm/Nd ratio for the accessible Earth. This must have been acquired during global silicate differentiation within the first 30 million years of Solar System formation and implies the formation of a complementary (142)Nd-depleted reservoir that either is hidden in the deep Earth, or lost to space by impact erosion. Whether this complementary reservoir existed, and whether or not it has been lost from Earth, is a matter of debate, and has implications for determining the bulk composition of Earth, its heat content and structure, as well as for constraining the modes and timescales of its geodynamical evolution. Here we show that, compared with chondrites, Earth's precursor bodies were enriched in neodymium that was produced by the slow neutron capture process (s-process) of nucleosynthesis. This s-process excess leads to higher (142)Nd/(144)Nd ratios; after correction for this effect, the (142)Nd/(144)Nd ratios of chondrites and the accessible Earth are indistinguishable within five parts per million. The (142)Nd offset between the accessible silicate Earth and chondrites therefore reflects a higher proportion of s-process neodymium in the Earth, and not early differentiation processes. As such, our results obviate the need for hidden-reservoir or super-chondritic Earth models and imply a chondritic Sm/Nd ratio for the bulk Earth. Although chondrites formed at greater heliocentric distances and contain a different mix of presolar components than Earth, they nevertheless are suitable proxies for Earth's bulk chemical composition.

  17. Alkalic rocks and resources of thorium and associated elements in the Powderhorn District, Gunnison County, Colorado

    USGS Publications Warehouse

    Olson, J.C.; Hedlund, D.C.

    1981-01-01

    Alkalic igneous rocks and related concentrations of thorium, niobium, rare-earth elements, titanium, and other elements have long been known in the Powderhorn mining district and have been explored intermittently for several decades. The deposits formed chiefly about 570 m.y. (million years) ago in latest Precambrian or Early Cambrian time. They were emplaced in lower Proterozoic (Proterozoic X) metasedimentary, metavolcanic, and plutonic rocks. The complex of alkalic rocks of Iron Hill occupies 31 km 2 (square kilometers) and is composed of pyroxenite, uncompahgrite, ijolite, nepheline syenite, and carbonatite, in order of generally decreasing age. Fenite occurs in a zone, in places more than 0.6 km (kilometer) wide, around a large part of the margin of the complex and adjacent to alkalic dikes intruding Precambrian host rock. The alkalic rocks have a radioactivity, chiefly due to thorium, greater than that of the surrounding Powderhorn Granite (Proterozoic X) and metamorphic rocks. The pyroxenite, uncompahgrite, ijolite, and nepheline syenite, which form more than 80 percent of the complex, have fairly uniform radioactivity. Radioactivity in the carbonatite stock, carbonatite dikes, and the carbonatite-pyroxenite mixed rock zone, however, generally exceeds that in the other rocks of the complex. The thorium concentrations in the Powderhorn district occur in six types of deposits: thorite veins, a large massive carbonatite body, carbonatite dikes, trachyte dikes, magnetite-ilmeniteperovskite dikes or segregations, and disseminations in small, anomalously radioactive plutons chiefly of granite or quartz syenite that are older than rocks of the alkalic complex. The highest grade thorium concentrations in the district are in veins that commonly occur in steeply dipping, crosscutting shear or breccia zones in the Precambrian rocks. They range in thickness from a centimeter or less to 5 m (meters) and are as much as 1 km long. The thorite veins are composed chiefly of potassic feldspar, white to smoky quartz, calcite, barite, goethite, and hematite, and also contain thorite, jasper, magnetite, pyrite, galena, chalcopyrite, sphalerite, synchysite, apatite, fluorite, biotite, sodic amphibole, rutile, monazite, bastnaesite, and vanadinite. The Th0 2 content of the thorite veins ranges from less than 0.01 percent to as much as 4.9 percent in high-grade samples. The Th0 2 content is generally less than 1 percent, however, and is only 0.05 to 0.1 percent in many of the veins examined in the district. Samples of the dolomitic carbonatite of Iron Hill mostly range from 3 to 145 ppm (parts per million) thorium. Thirty samples of the carbonatite dikes, the most radioactive rocks within the complex of Iron Hill, contain about 30 to 3,200 ppm thorium and a trace to about 1.5 percent rare-earth oxides. The magnetite-ilmenite-perovskite rocks have a radioactivity of 2 to 12 times the background of Precambrian granite that is attributable chiefly to thorium substitution for calcium in the perovskite. In two analyses the perovskite contains 0.12 and 0.15 percent Th0 2 . Trachyte dikes as much as 25 m thick cut the Precambrian rocks; their radioactivity is generally about two to four times the background of typical Precambrian granite, is locally higher, but is low relative to other types of thorium concentrations. A finegrained granite that is anomalously radioactive occurs in thick, dikelike plutons as much as 1.2 km wide, or more. The thorium content varies widely within the granite bodies. Eight samples of the granite contain 32 to 281 ppm thorium (averaging 115 ppm). The economic potential of thorium in the Powderhorn district is related in part to other elements such as niobium, titanium, iron, and rare earths. The proportions of niobium and rare earths to thorium vary in different parts of the district. Within the carbonatite body of Iron Hill, the Nb 2 0 5 content greatly exceeds Th0 2 , but the Th0 2 -Nb 2 0 5

  18. Properties of iron alloys under the Earth's core conditions

    NASA Astrophysics Data System (ADS)

    Morard, Guillaume; Andrault, Denis; Antonangeli, Daniele; Bouchet, Johann

    2014-05-01

    The Earth's core is constituted of iron and nickel alloyed with lighter elements. In view of their affinity with the metallic phase, their relative high abundance in the solar system and their moderate volatility, a list of potential light elements have been established, including sulfur, silicon and oxygen. We will review the effects of these elements on different aspects of Fe-X high pressure phase diagrams under Earth's core conditions, such as melting temperature depression, solid-liquid partitioning during crystallization, and crystalline structure of the solid phases. Once extrapolated to the inner-outer core boundary, these petrological properties can be used to constrain the Earth's core properties.

  19. Petrography and geochemistry of clastic sedimentary rocks as evidences for provenance of the Lower Cambrian Lalun Formation, Posht-e-badam block, Central Iran

    NASA Astrophysics Data System (ADS)

    Etemad-Saeed, N.; Hosseini-Barzi, M.; Armstrong-Altrin, John S.

    2011-09-01

    Petrography and geochemistry (major, trace and rare earth elements) of clastic rocks from the Lower Cambrian Lalun Formation, in the Posht-e-badam block, Central Iran, have been investigated to understand their provenance. Petrographical analysis suggests that the Lalun conglomerates are dominantly with chert clasts derived from a proximal source, probably chert bearing Precambrian Formations. Similarly, purple sandstones are classified as litharenite (chertarenite) and white sandstones as quartzarenite types. The detrital modes of purple and white sandstones indicate that they were derived from recycled orogen (uplifted shoulders of rift) and stable cratonic source. Most major and trace element contents of purple sandstones are generally similar to upper continental crust (UCC) values. However, white sandstones are depleted in major and trace elements (except SiO 2, Zr and Co) relative to UCC, which is mainly due to the presence of quartz and absence of other Al-bearing minerals. Shale samples have considerably lower content in most of the major and trace elements concentration than purple sandstones, which is possibly due to intense weathering and recycling. Modal composition (e.g., quartz, feldspar, lithic fragments) and geochemical indices (Th/Sc, La/Sc, Co/Th, Cr/Th, Cr/V and V/Ni ratios) of sandstones, and shales (La/Sc and La/Cr ratios) indicate that they were derived from felsic source rocks and deposited in a passive continental margin. The chondrite-normalized rare earth element (REE) patterns of the studied samples are characterized by LREE enrichment, negative Eu anomaly and flat HREE similar to an old upper continental crust composed chiefly of felsic components in the source area. The study of paleoweathering conditions based on modal composition, chemical index of alteration (CIA), plagioclase index of alteration (PIA) and A-CN-K (Al 2O 3 - CaO + Na 2O - K 2O) relationships indicate that probably chemical weathering in the source area and recycling processes have been more important in shale and white sandstones relative to purple sandstones. The results of this study suggest that the main source for the Lalun Formation was likely located in uplifted shoulders of a rifted basin (probably a pull-apart basin) in its post-rift stage (Pan-African basement of the Posht-e-badam block).

  20. Antibacterial, Antifungal and Nematicidal Activities of Rare Earth Ions.

    PubMed

    Wakabayashi, Tokumitsu; Ymamoto, Ayumi; Kazaana, Akira; Nakano, Yuta; Nojiri, Yui; Kashiwazaki, Moeko

    2016-12-01

    Despite the name, rare earth elements are relatively abundant in soil. Therefore, these elements might interact with biosphere during the history of life. In this study, we have examined the effect of rare earth ions on the growth of bacteria, fungi and soil nematode. All rare earth ions, except radioactive promethium that we have not tested, showed antibacterial and antifungal activities comparable to that of copper ions, which is widely used as antibacterial metals in our daily life. Rare earth ions also have nematicidal activities as they strongly perturb the embryonic development of the nematode, Caenorhabditis elegans. Interestingly, the nematicidal activity increased with increasing atomic number of lanthanide ions. Since the rare earth ions did not show high toxicity to the human lymphoblastoid cell line or even stimulate the growth of the cultured cells at 1 mM, it raised the possibility that we can substitute rare earth elements for the antibacterial metals usually used because of their safety.

  1. Components for Maintaining and Publishing Earth Science Vocabularies

    NASA Astrophysics Data System (ADS)

    Cox, S. J. D.; Yu, J.

    2014-12-01

    Shared vocabularies are an important aid to geoscience data interoperability. Many organizations maintain useful vocabularies, with Geologic Surveys having a particularly long history of vocabulary and lexicon development. However, the mode of publication is heterogeneous, ranging from PDFs and HTML web pages, spreadsheets and CSV, through various user-interfaces and APIs. Update and maintenance ranges from tightly-governed and externally opaque, through various community processes, all the way to crowd-sourcing ('folksonomies'). A general expectation, however, is for greater harmonization and vocabulary re-use. In order to be successful this requires (a) standardized content formalization and APIs (b) transparent content maintenance and versioning. We have been trialling a combination of software dealing with registration, search and linking. SKOS is designed for formalizing multi-lingual, hierarchical vocabularies, and has been widely adopted in earth and environmental sciences. SKOS is an RDF vocabulary, for which SPARQL is the standard low-level API. However, for interoperability between SKOS vocabulary sources, a SKOS-based API (i.e. based on the SKOS predicates prefLabel, broader, narrower, etc) is required. We have developed SISSvoc for this purpose, and used it to deploy a number of vocabularies on behalf of the IUGS, ICS, NERC, OGC, the Australian Government, and CSIRO projects. SISSvoc Search provides simple search UI on top of one or more SISSvoc sources. Content maintenance is composed of many elements, including content-formalization, definition-update, and mappings to related vocabularies. Typically there is a degree of expert judgement required. In order to provide confidence in users, two requirements are paramount: (i) once published, a URI that denotes a vocabulary item must remain dereferenceable; (ii) the history and status of the content denoted by a URI must be available. These requirements match the standard 'registration' paradigm which is implemented in the Linked Data Registry, which is currently used by WMO and the UK Environment Agency for publication of vocabularies. Together, these components provide a powerful and flexible system for providing earth science vocabularies for the community, consistent with semantic web and linked-data principles.

  2. Manufacturing of Dysprosium-Iron Alloys by Electrolysis in Fluoride-Based Electrolytes: Oxide Solubility Determinations

    NASA Astrophysics Data System (ADS)

    Martinez, Ana Maria; Støre, Anne; Osen, Karen Sende

    2018-04-01

    Electrolytic production of light rare earth elements and alloys takes place in a fluoride-based electrolyte using rare earth oxides as raw material. The optimization of this method, mainly in terms of the energy efficiency and environmental impact control, is rather challenging. Anode effects, evolution of fluorine-containing compounds, and side cathode reactions could largely be minimized by a good control of the amount of rare earth oxide species dissolved in the fluoride-based electrolyte and their dissolution rate. The oxide content of the fluoride melts REF3-LiF (RE = Nd, Dy) at different compositions and temperatures were experimentally determined by carbothermal analysis of melt samples. The highest solubility values of oxide species, added as Dy2O3 and Dy2(CO3)3, were obtained to be of ca. 3 wt pct (expressed as Dy2O3) in the case of the equimolar DyF3-LiF melt at 1323 K (1050 °C). The oxide saturation values increased with the amount of REF3 present in the molten bath and the working temperature.

  3. Probable age of Autolycus and calibration of lunar stratigraphy

    NASA Technical Reports Server (NTRS)

    Ryder, G.; Bogard, D.; Garrison, D.

    1991-01-01

    Ar-39 - Ar-40 analyses of three petrographically distinct, shocked Apollo 15 KREEP (i.e., high K, rare earth element, P, and other trace element contents) basalt samples demonstrate that a major impact event affected all three samples at about 2.1 Ga. The Copernican System craters Aristillus and Autolycus are to the north. Autolycus, the older of the two, is in a particularly appropriate terrain and is the most likely source of the 2.1 Ga heating and delivery event. With this calibration point, and if Autolycus really is a Copernican crater, the Copernican System lasted twice as long as has previously been suggested. Furthermore, the moon was not subjected to a constant cratering rate over the past 3 billion years; the average rate in the preceding Eratosthenian must have been twice that in the Copernican.

  4. 75 FR 25850 - Materials Strategy Request for Information

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-10

    ... (DOE) is seeking information from stakeholders on rare earth elements and other materials used in... strategic plan for addressing the role of rare earth elements and other materials in energy technologies and...

  5. Anthropogenic disturbance of element cycles at the Earth's surface.

    PubMed

    Sen, Indra S; Peucker-Ehrenbrink, Bernhard

    2012-08-21

    The extent to which humans are modifying Earth's surface chemistry can be quantified by comparing total anthropogenic element fluxes with their natural counterparts (Klee and Graedel, 2004). We quantify anthropogenic mass transfer of 77 elements from mining, fossil fuel burning, biomass burning, construction activities, and human apportionment of terrestrial net primary productivity, and compare it to natural mass transfer from terrestrial and marine net primary productivity, riverine dissolved and suspended matter fluxes to the ocean, soil erosion, eolian dust, sea-salt spray, cosmic dust, volcanic emissions, and for helium, hydrodynamic escape from the Earth's atmosphere. We introduce an approach to correct for losses during industrial processing of elements belonging to geochemically coherent groups, and explicitly incorporate uncertainties of element mass fluxes through Monte Carlo simulations. We find that at the Earth's surface anthropogenic fluxes of iridium, osmium, helium, gold, ruthenium, antimony, platinum, palladium, rhenium, rhodium and chromium currently exceed natural fluxes. For these elements mining is the major factor of anthropogenic influence, whereas petroleum burning strongly influences the surficial cycle of rhenium. Our assessment indicates that if anthropogenic contributions to soil erosion and eolian dust are considered, anthropogenic fluxes of up to 62 elements surpass their corresponding natural fluxes.

  6. Bulk composition of the Moon in the context of models for condensation in the solar nebula

    NASA Technical Reports Server (NTRS)

    Goettel, K. A.

    1984-01-01

    The FeO content of the Moon is substantially higher than the present FeO content of the Earth's mantle. If the Moon formed by fission from the Earth's mantle, then the conclusion that the Earth's mantle must have been much richer in FeO at the time of fission appears firm. If the Moon formed independently in geocentric orbit, then the FeO contents of the two bodies should be similar, because both would be accreting from the same source of silicate material. Therefore, Earth's mantle at the time of lunar formation probably had an FeO content quite similar to the present FeO content of the Moon. This conclusion, if valid, has profound implications in two areas: (1) the differentiation history of the Earth's mantle and core; and (2) the processes responsible for governing the bulk compositions of the terrestrial planets. If Earth had more FeO than previously thought, then the composition differences between Earth and Mars are less than previously believed. This suggests that condensation temperature and heliocentric distance may have been less important in governing planetary compositions and other mechanisms, including iron/silicate fractionation may have been more important. The implication of this model for the compositions of the Moon and the other terrestrial planets are discussed.

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

    PubMed

    Du, Xiaoyue; Graedel, T E

    2013-09-01

    The rare earth elements (REE) are a group of fifteen elements with unique properties that make them indispensable for a wide variety of emerging and conventional established technologies. However, quantitative knowledge of REE remains sparse, despite the current heightened interest in future availability of the resources. Mining is heavily concentrated in China, whose monopoly position and potential restriction of exports render primary supply vulnerable to short term disruption. We have drawn upon the published literature and unpublished materials in different languages to derive the first quantitative annual domestic production by end use of individual rare earth elements from 1995 to 2007. The information is illustrated in Sankey diagrams for the years 1995 and 2007. Other years are available in the supporting information. Comparing 1995 and 2007, the production of the rare earth elements in China, Japan, and the US changed dramatically in quantities and structure. The information can provide a solid foundation for industries, academic institutions and governments to make decisions and develop strategies. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. CO 2-rich komatiitic melt inclusions in Cr-spinels within beach sand from Gorgona Island, Colombia

    NASA Astrophysics Data System (ADS)

    Shimizu, Kenji; Shimizu, Nobumichi; Komiya, Tsuyoshi; Suzuki, Katsuhiko; Maruyama, Shigenori; Tatsumi, Yoshiyuki

    2009-10-01

    The volatile content of komatiite is a key to constrain the thermal and chemical evolution of the deep Earth. We report the volatile contents with major and trace element compositions of ~ 80 melt inclusions in chromian spinels (Cr-spinels) from beach sands on Gorgona Island, Colombia. Gorgona Island is a ~ 90 Ma volcanic island, where picrites and the youngest komatiites known on the Earth are present. Melt inclusions are classified into three types on the basis of their host Cr-spinel compositions: low Ti (P type), high Ti with high Cr # (K1 type) and high Ti with low Cr # (K2 type). Chemical variations of melt inclusions in the Cr-spinels cover all of the island's lava types. P-type inclusions mainly occur in the picrites, K1-type in high-TiO 2 komatiites (some enriched basalts: E-basalts) and K2-type in low-TiO 2 komatiites. The H 2O and CO 2 contents of melt inclusions within Cr-spinels from the beach sand are highly variable (H 2O: 0.03-0.9 wt.%; CO 2: 40-4000 ppm). Evaluation of volatile content is not entirely successful because of compositional alterations of the original melt by degassing, seawater/brine assimilation and post-entrapment modification of certain elements and volatiles. However, the occurrence of many melt inclusions with low H 2O/K 2O ratios indicates that H 2O/K 2O of Gorgona komatiite is not much different from that of modern mid-oceanic ridge basalt (MORB) or oceanic island basalt. Trend of CO 2/Nb and Zr/Y ratios, accounted for by two-component mixing between the least degassed primary komatiite and low-CO 2/Nb evolved basalt, allow us to estimate a primary CO 2/Nb ratio of 4000 ± 2200 or a CO 2 content of 0.16 ± 0.09 wt.%. The determined CO 2/Nb ratio is unusually high, compared to that of MORB (530). Although the presence of CO 2 in the Gorgona komatiite does not affect the magma generation temperature, CO 2 degassing may have contributed to the eruption of high-density magmas. High CO 2/Nb and the relatively anhydrous nature of Gorgona komatiite provide possible resolution to one aspect of the hydrous komatiite debate.

  9. Bioleaching of rare earth elements from monazite sand.

    PubMed

    Brisson, Vanessa L; Zhuang, Wei-Qin; Alvarez-Cohen, Lisa

    2016-02-01

    Three fungal strains were found to be capable of bioleaching rare earth elements from monazite, a rare earth phosphate mineral, utilizing the monazite as a phosphate source and releasing rare earth cations into solution. These organisms include one known phosphate solubilizing fungus, Aspergillus niger ATCC 1015, as well as two newly isolated fungi: an Aspergillus terreus strain ML3-1 and a Paecilomyces spp. strain WE3-F. Although monazite also contains the radioactive element Thorium, bioleaching by these fungi preferentially solubilized rare earth elements over Thorium, leaving the Thorium in the solid residual. Adjustments in growth media composition improved bioleaching performance measured as rare earth release. Cell-free spent medium generated during growth of A. terreus strain ML3-1 and Paecilomyces spp. strain WE3-F in the presence of monazite leached rare earths to concentrations 1.7-3.8 times those of HCl solutions of comparable pH, indicating that compounds exogenously released by these organisms contribute substantially to leaching. Organic acids released by the organisms included acetic, citric, gluconic, itaconic, oxalic, and succinic acids. Abiotic leaching with laboratory prepared solutions of these acids was not as effective as bioleaching or leaching with cell-free spent medium at releasing rare earths from monazite, indicating that compounds other than the identified organic acids contribute to leaching performance. © 2015 Wiley Periodicals, Inc.

  10. Chemical evolution of the Earth: Equilibrium or disequilibrium process?

    NASA Technical Reports Server (NTRS)

    Sato, M.

    1985-01-01

    To explain the apparent chemical incompatibility of the Earth's core and mantle or the disequilibrium process, various core forming mechanisms have been proposed, i.e., rapid disequilibrium sinking of molten iron, an oxidized core or protocore materials, and meteorite contamination of the upper mantle after separation from the core. Adopting concepts used in steady state thermodynamics, a method is devised for evaluating how elements should distribute stable in the Earth's interior for the present gradients of temperature, pressure, and gravitational acceleration. Thermochemical modeling gives useful insights into the nature of chemical evolution of the Earth without overly speculative assumptions. Further work must be done to reconcile siderophile elements, rare gases, and possible light elements in the outer core.

  11. Rare Earth Element Geochemistry for Produced Waters, WY

    DOE Data Explorer

    Quillinan, Scott; Nye, Charles; McLing, Travis; Neupane, Hari

    2016-06-30

    These data represent major, minor, trace, isotopes, and rare earth element concentrations in geologic formations and water associated with oil and gas production. *Note - Link below contains updated version of spreadsheet (6/14/2017)

  12. [Leaching of Rare Earth Elements from Coal Ashes Using Acidophilic Chemolithotrophic Microbial Communities].

    PubMed

    Muravyov, M I; Bulaev, A G; Melamud, V S; Kondrat'eva, T F

    2015-01-01

    A method for leaching rare earth elements from coal ash in the presence of elemental sulfur using communities of acidophilic chemolithotrophic microorganisms was proposed. The optimal parameters determined for rare element leaching in reactors were as follows: temperature, 45 degrees C; initial pH, 2.0; pulp density, 10%; and the coal ash to elemental sulfur ratio, 10 : 1. After ten days of leaching, 52.0, 52.6, and 59.5% of scandium, yttrium, and lanthanum, respectively, were recovered.

  13. Element Abundances in Meteorites and the Earth: Implication for the Accretion of Planetary Bodies

    NASA Astrophysics Data System (ADS)

    Mezger, K.; Vollstaedt, H.; Maltese, A.

    2017-12-01

    Essentially all known inner solar system materials show near chondritic relative abundances of refractory elements and depletion in volatile elements. To a first approximation volatile element depletion correlates with the respective condensation temperature (TC) of the elements. Possible mechanisms for this depletion are incomplete condensation and partial loss by evaporation caused by heating prior to or during the planetesimal accretion. The stable isotope compositions of almost all moderately volatile elements in different meteorite classes show only minor, or no evidence for a Rayleigh-type fractionation that could be attributed to partial condensation or evaporation. The different classes of meteorites also show that the degree of depletion in their parent bodies (i.e. mostly planetesimals) is quite variable, but nevertheless systematic. For primitive and least disturbed carbonaceous chondrites the element depletion pattern is a smooth function of TC. The accessible silicate Earth also shows this general depletion pattern, but in detail it is highly complex and requires differentiation processes that are not solely controlled by TC. If only highly lithophile elements are considered the depletion pattern of the silicate Earth reveals a step function that shows that moderately volatile lithophile elements have abundances that are ca. 0.1 times the chondritic value, irrespective of their TC. This element pattern observed for bulk silicate Earth can be modelled as a mixture of two distinct components: ca. 90% of a strongly reduced planetary body that is depleted in highly volatile elements and ca. 10% of a more volatile element rich and oxidized component. This mixture can account for the apparent Pb- paradox observed in melts derived from the silicate Earth and provides a time constraint for the mixing event, which is ca. 70 My after the beginning of the solar system. This event corresponds to the giant impact that also formed the Moon.

  14. Mantle and crustal contributions to continental flood volcanism

    USGS Publications Warehouse

    Arndt, N.T.; Czamanske, G.K.; Wooden, J.L.; Fedorenko, V.A.

    1993-01-01

    Arndt, N.T., Czamanske, G.K., Wooden, J.L. and Fedorenko, V.A., 1993. Mantle and crustal contributions to continental flood volcanism. In: M.J.R. Wortel, U. Hansen and R. Sabadini (Editors), Relationships between Mantle Processes and Geological Processes at or near the Earth's Surface. Tectonophysics, 223: 39-52. Most continental flood basalts are enriched in incompatible elements and have high initial 87Sr/86Sr ratios and low ??{lunate}Nd values. Many are depleted in Nb and Ta. The commonly-held view that these characteristics are inherited directly from a source in metasomatized lithospheric mantle is inconsistent with the following arguments: (1) thermomechanical modelling demonstrates that flood basalt magmas come mainly from an asthenospheric or plume source, with minimal direct melting of the continental lithospheric mantle. The low water contents of most flood basalts argue against proposals that hydrous lithosphere was the source. (2) Lithospheric mantle normally has low concentrations of incompatible elements, and chondrite-normalized Nb and Ta contents similar to those of other incompatible elements. Such material cannot be the unmodified source of Nb-Ta-depleted basalts such as those from the Karoo, Ferrar, or Columbia River provinces. We suggest there are two main controls on the compositions of continental flood basalts. The first is lithospheric thickness, which strongly influences the depth and degree of mantle melting of a plume or asthenospheric source, and thus has an important influence on the composition of primary magmas. All liquids formed by partial melting of peridotite at sub-lithosphere depths are highly magnesian (20-25 wt.% MgO) but have variable trace-element contents. Where the lithosphere is thick, the source melts at high pressure, garnet is present, the degree of melting is low, and trace-element concentrations are high. This type of magma evolves to produce the high-Ti type of continental flood basalt. Where the lithosphere is thinner, the source ascends to shallower levels, the degree of melting is greater, garnet may be exhausted, and the magmas have lower trace-element contents; these magmas yield low-Ti basalts. The second control is processing of magmas in chambers that were periodically replenished and tapped, while continuously fractionating and assimilating their wall rocks. The uniform compositions of basalts that evolve in such chambers are far removed from those of their picritic parental magmas. Major elements in continental flood basalts reflect control by olivine, pyroxene, and plagioclase crystallization, and this assemblage places the magma chambers at crustal depth. We believe that trace-element and isotopic compositions are also buffered, and that the erupted basalts represent steady-state liquids tapped from these magma chambers. These processes impose a crustal signature on the magmas, as expressed most strongly in the concentrations of incompatible elements (e.g., Nb-Ta anomalies) and their isotopic characteristics. ?? 1993.

  15. Value analysis of neodymium content in shredder feed: toward enabling the feasibility of rare earth magnet recycling.

    PubMed

    Bandara, H M Dhammika; Darcy, Julia W; Apelian, Diran; Emmert, Marion H

    2014-06-17

    In order to facilitate the development of recycling technologies for rare earth magnets from postconsumer products, we present herein an analysis of the neodymium (Nd) content in shredder scrap. This waste stream has been chosen on the basis of current business practices for the recycling of steel, aluminum, and copper from cars and household appliances, which contain significant amounts of rare earth magnets. Using approximations based on literature data, we have calculated the average Nd content in the ferrous shredder product stream to be between 0.13 and 0.29 kg per ton of ferrous scrap. A value analysis considering rare earth metal prices between 2002 and 2013 provides values between $1.32 and $145 per ton of ferrous scrap for this material, if recoverable as pure Nd metal. Furthermore, we present an analysis of the content and value of other rare earths (Pr, Dy, Tb).

  16. Recovery of rare earths from spent NdFeB magnets of wind turbine: Leaching and kinetic aspects.

    PubMed

    Kumari, Aarti; Sinha, Manish Kumar; Pramanik, Swati; Sahu, Sushanta Kumar

    2018-05-01

    Increasing demands of rare earth (RE) metals for advanced technological applications coupled with the scarcity of primary resources have led to the development of processes to treat secondary resources like scraps or end of life products that are often rich in such metals. Spent NdFeB magnet may serve as a potential source of rare earths containing around ∼30% of neodymium and other rare earths. In the present investigation, a pyro-hydrometallurgical process has been developed to recover rare earth elements (Nd, Pr and Dy) from the spent wind turbine magnet. The spent magnet is demagnetized and roasted at 1123 K to convert rare earths and iron to their respective oxides. Roasting of the magnet not only provides selectivity, but enhances the leaching efficiency also. The leaching of the roasted sample with 0.5 M hydrochloric acid at 368 K, 100 g/L pulp density and 500 rpm for 300 min selectively recovers the rare earth elements almost quantitatively leaving iron oxide in the residue. Leaching of rare earth elements with hydrochloric acid follows the mixed controlled kinetic model with activation energy (E a ) of 30.1 kJ/mol in the temperature range 348-368 K. The leaching mechanism is further established by characterizing the leach residues obtained at different time intervals by scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD). Individual rare earth elements from the leach solution containing 16.8 g/L of Nd, 3.8 g/L Pr, 0.28 g/L of Dy and other minor impurity elements could be separated by solvent extraction. However, mixed rare earth oxide of 99% purity was produced by oxalate precipitation followed by roasting. The leach residue comprising of pure hematite has a potential to be used as pigment or can find other applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Are C1 chondrites chemically fractionated - A trace element study

    NASA Technical Reports Server (NTRS)

    Ebihara, M.; Wolf, R.; Anders, E.

    1982-01-01

    Six C1 chondrite samples and a C2 xenolith from the Plainview H5 chondrite were analyzed by radiochemical neutron activation for a large variety of elements, including rare earths. The sample processing is described, including the irradiation, chemical procedure, rare earths separation, counting techniques, radiochemical purity check, and chemical yields. The results of consistency checks on a number of elements are discussed. Abundances for siderophiles, volatiles, and rare earths are presented and discussed. Tests are presented for fractionation of rare earths and other refractories, compositional uniformity of C1's, and interelement correlations. There is no conclusive evidence for nebular fractionation affecting C1's. Three fractionation-prone rare earths have essentially the same relative abundances in C1's and all other chondrite classes, and hence are apparently not fractionated in C1's.

  18. COST-EFFECTIVE RARE EARTH ELEMENT RECYCLING PROCESS FROM INDUSTRIAL SCRAP AND DISCARDED ELECTRONIC PRODUCTS TO VALUABLE MAGNETIC ALLOYS AND PERMANENT MAGNETS - PHASE II

    EPA Science Inventory

    Rare earth element (REE) based Nd-Fe-B and Sm-Co permanent magnets have been widely used because of their excellent magnetic properties. The applications of Nd-Fe-B and Sm-Co rare earth permanent magnets include hybrid electric vehicles (HEVs), power generators for wind tur...

  19. Water contents of clinopyroxenes from sub-arc mantle peridotites

    USGS Publications Warehouse

    Turner, Michael; Turner, Simon; Blatter, Dawnika; Maury, Rene; Perfit, Michael; Yogodzinski, Gene

    2017-01-01

    One poorly constrained reservoir of the Earth's water budget is that of clinopyroxene in metasomatised, mantle peridotites. This study presents reconnaissance Sensitive High-Resolution, Ion Microprobe–Stable Isotope (SHRIMP–SI) determinations of the H2O contents of (dominantly) clinopyroxenes in rare mantle xenoliths from four different subduction zones, i.e. Mexico, Kamchatka, Philippines, and New Britain (Tabar-Feni island chain) as well as one intra-plate setting (western Victoria). All of the sub-arc xenoliths have been metasomatised and carry strong arc trace element signatures. Average measured H2O contents of the pyroxenes range from 70 ppm to 510 ppm whereas calculated bulk H2O contents range from 88 ppm to 3 737 ppm if the variable presence of amphibole is taken into account. In contrast, the intra-plate, continental mantle xenolith from western Victoria has higher water contents (3 447 ppm) but was metasomatised by alkali and/or carbonatitic melts and does not carry a subduction-related signature. Material similar to the sub-arc peridotites can either be accreted to the base of the lithosphere or potentially be transported by convection deeper into the mantle where it will lose water due to amphibole breakdown.

  20. Substitution of Nd with other rare earth elements in melt spun Nd{sub 2}Fe{sub 14}B magnets

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brown, D. N.; Lau, D.; Chen, Z.

    2016-05-15

    This is a contemporary study of rapidly quenched Nd{sub 1.6}X{sub 0.4}Fe{sub 14}B magnetic materials (where X= Nd, Y, Ce, La, Pr, Gd and Ho). A 20% substitution of the Nd component from Nd{sub 2}Fe{sub 14}B can bring about some commercial advantage. However, there will be some compromise to the magnetic performance. Light rare earth elements are definitely more abundant (Y, Ce, La) than the heavier rare earth elements, but when they are included in RE{sub 2}Fe{sub 14}B magnets they tend to lower magnetic performance and thermal stability. Substituting heavy rare earth elements (Gd, Ho) for Nd in Nd{sub 2}Fe{sub 14}Bmore » improves the thermal stability of magnets but causes a loss in magnet remanence.« less

  1. U.S. trade dispute with China over rare earth elements

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2012-03-01

    The U.S. government has brought a new trade case against China over rare earth elements (REE) as well as tungsten and molybdenum, President Barack Obama announced on 13 March. Japan and the European Union also have taken similar actions against China about REEs, which are a group of 17 chemically similar metallic elements that are used in a variety of electronic, optical, magnetic, and catalytic applications. REEs are plentiful in the Earth's crust, although China currently has about 37% of the world's reserves and accounts for more than 95% of the world's production of the elements, according to the British Geological Survey. The United States has requested consultations with China at the World Trade Organization (WTO) concerning "China's unfair export restraints on rare earths, as well as tungsten and molybdenum," the Office of the United States Trade Representative announced in a 13 March statement.

  2. Production and precipitation of rare earth elements in acidic to alkaline coal mine discharges, Appalachian Basin, USA

    NASA Astrophysics Data System (ADS)

    Stewart, B. W.; Capo, R. C.; Hedin, B. C.; Wallrich, I. L. R.; Hedin, R. S.

    2016-12-01

    Abandoned coal mine discharges are a serious threat to ground and surface waters due to their high metal content and often high acidity. However, these discharges represent a potential source of rare earth elements (REE), many of which are considered to be critical resources. Trace element data from 18 coal mine drainage (CMD) sites within the Appalachian Basin suggest CMD is enriched in total REE by 1-4 orders of magnitude relative to concentrations expected in unaffected surface or ground waters. When normalized to the North American Shale Composite (NASC), the discharges generally show a pattern of enrichment in the middle REE, including several identified as critical resources (Nd, Eu, Dy, Tb). In contrast, shale, sandstone and coal samples from Appalachian Basin coal-bearing units have concentrations and patterns similar to NASC, indicating that the REE in CMD are fractionated during interaction with rock in the mine pool. The highest total REE contents (up to 2800 mg/L) are found in low-pH discharges (acid mine drainage, or AMD). A precipitous drop in REE concentration in CMD with pH ≥6.6 suggests adsorption or precipitation of REE in the mine pool at circumneutral pH. Precipitated solids from 21 CMD active and passive treatment sites in the Appalachian Basin, including Fe oxy-hydroxides, Ca-Mg lime slurries, and Si- and Al-rich precipitates, are enriched in total REE content relative to the average CMD discharges by about four orders of magnitude. Similar REE trends in the discharges and precipitates, including MREE enrichment, suggest minimal fractionation of REE during precipitation; direct comparisons over multiple seasonal cycles are needed to confirm this. Although the data are limited, Al-rich precipitates generally have high REE concentrations, while those in iron oxy-hydroxides tend to be lower. Based on the area of mined coal in the Appalachian Basin, estimated infiltration rates, and the mean REE flux from discharges analyzed in this study and that of Cravotta and Brady (2015, Appl. Geochem. 62, 108-130), we estimate that coal mine drainage outflows in this region generate approximately 450 metric tons of dissolved REE per year, a portion of which could be targeted for resource recovery during CMD treatment.

  3. (BRI) Direct and Inverse Design Optimization of Magnetic Alloys with Minimized Use of Rare Earth Elements

    DTIC Science & Technology

    2016-02-02

    Earths ”, MS&T15-Materials Science and Technology 2015 Conference, Columbus, Ohio, October 4-8, 2015. 3. Dulikrvich, G.S., Reddy, S., Orlande, H.R.B...Schwartz, J.and Koch, C.C., “Multi-Objective Design and Optimization of Hard Magnetic Alloys Free of Rare Earths ”, MS&T15-Materials Science and Technology...AFRL-AFOSR-VA-TR-2016-0091 (BRI) Direct and Inverse Design Optimization of Magnetic Alloys with Minimized Use of Rare Earth Elements George

  4. Genetic Nature of Elemental Contents in Wheat Grains and Its Genomic Prediction: Toward the Effective Use of Wheat Landraces from Afghanistan

    PubMed Central

    Yamaoka, Shuhei; Yoshimura, Kazusa; Kondou, Youichi; Onogi, Akio; Matsui, Minami; Iwata, Hiroyoshi; Ban, Tomohiro

    2017-01-01

    Profiling elemental contents in wheat grains and clarifying the underlying genetic systems are important for the breeding of biofortified crops. Our objective was to evaluate the genetic potential of 269 Afghan wheat landraces for increasing elemental contents in wheat cultivars. The contents of three major (Mg, K, and P) and three minor (Mn, Fe, and Zn) elements in wheat grains were measured by energy dispersive X-ray fluorescence spectrometry. Large variations in elemental contents were observed among landraces. Marker-based heritability estimates were low to moderate, suggesting that the elemental contents are complex quantitative traits. Genetic correlations between two locations (Japan and Afghanistan) and among the six elements were estimated using a multi-response Bayesian linear mixed model. Low-to-moderate genetic correlations were observed among major elements and among minor elements respectively, but not between major and minor elements. A single-response genome-wide association study detected only one significant marker, which was associated with Zn, suggesting it will be difficult to increase the elemental contents of wheat by conventional marker-assisted selection. Genomic predictions for major elemental contents were moderately or highly accurate, whereas those for minor elements were mostly low or moderate. Our results indicate genomic selection may be useful for the genetic improvement of elemental contents in wheat. PMID:28072876

  5. A miniature single element effusion cell for the vacuum deposition of transition-metal and rare-earth elements

    NASA Astrophysics Data System (ADS)

    Harris, V. G.; Koon, N. C.

    1997-08-01

    A miniature single element effusion cell has been fabricated and tested that allows for the high-vacuum deposition of a variety of transition-metal and rare-earth elements. The cell is designed to operate under high-vacuum conditions, ≈10-9 Torr, with low power demands, <200 W. The virtues of this evaporator are the simplicity of design and ease of fabrication, assembly, maintenance, and operation.

  6. Alaska's rare earth deposits and resource potential

    USGS Publications Warehouse

    Barker, James C.; Van Gosen, Bradley S.

    2012-01-01

    Alaska’s known mineral endowment includes some of the largest and highest grade deposits of various metals, including gold, copper and zinc. Recently, Alaska has also been active in the worldwide search for sources of rare earth elements (REE) to replace exports now being limitedby China. Driven by limited supply of the rare earths, combined with their increasing use in new ‘green’ energy, lighting, transportation, and many other technological applications, the rare earth metals neodymium, europium and, in particular, the heavy rare earth elements terbium, dysprosium and yttrium are forecast to soon be in critical short supply (U.S. Department of Energy, 2010).

  7. Mineral resource of the month: rare earths

    USGS Publications Warehouse

    Hedrick, James B.

    2004-01-01

    As if classified as a top-secret project, the rare earths have been shrouded in secrecy. The principal ore mineral of the group, bastnäsite, rarely appears in the leading mineralogy texts. The long names of the rare-earth elements and some unusual arrangements of letters, many Scandinavian in origin, may have intimidated even those skilled in phonics. Somewhat obscurely labeled, the rare earths are neither rare nor earths (the historical term for oxides). They are a relatively abundant group of metallic elements that occur in nature as nonmetallic compounds and have hundreds of commercial applications.

  8. A nucleosynthetic origin for the Earth’s anomalous 142Nd composition

    PubMed Central

    Burkhardt, C.; Borg, L.E.; Brennecka, G.A.; Shollenberger, Q.R.; Dauphas, N.; Kleine, T.

    2016-01-01

    A long-standing paradigm assumes that the chemical and isotopic composition of many elements in the bulk silicate Earth are the same as in chondrites1–4. However, the accessible Earth has a greater 142Nd/144Nd than chondrites. Because 142Nd is the decay product of now-extinct 146Sm (t1/2= 103 million years5), this 142Nd difference seems to require a higher-than-chondritic Sm/Nd of the accessible Earth. This must have been acquired during global silicate differentiation within the first 30 million years of Solar System formation6 and implies the formation of a complementary 142Nd-depleted reservoir that either is hidden in the deep Earth6, or was lost to space by impact erosion3,7. Whether this complementary reservoir existed, and whether or not it has been lost from Earth is a matter of debate3,8,9, but has tremendous implications for determining the bulk composition of Earth, its heat content and structure, and for constraining the modes and timescales of its geodynamical evolution3,7,9,10. Here, we show that compared to chondrites, Earth’s precursor bodies were enriched in Nd produced by the slow neutron capture process (s-process) of nucleosynthesis. This s-process excess leads to higher 142Nd/144Nd, and, after correction for this effect, the 142Nd/144Nd of chondrites and the accessible Earth are indistinguishable within 5 parts per million. The 142Nd offset between the accessible silicate Earth and chondrites, therefore, reflects a higher proportion of s-process Nd in the Earth, and not early differentiation processes. As such, our results obviate the need for hidden reservoir or super-chondritic Earth models, and imply a chondritic Sm/Nd for bulk Earth. Thus, although chondrites formed at greater heliocentric distance and contain a different mix of presolar components than Earth, they nevertheless are suitable proxies for Earth’s bulk chemical composition. PMID:27629643

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

    USGS Publications Warehouse

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

    2000-01-01

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

  10. Am phases in the matrix of a U–Pu–Zr alloy with Np, Am, and rare-earth elements

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Janney, Dawn E.; Kennedy, J. Rory; Madden, James W.

    2015-01-01

    Phases and microstructures in the matrix of an as-cast U-Pu-Zr alloy with 3 wt% Am, 2% Np, and 8% rare-earth elements were characterized by scanning and transmission electron microscopy. The matrix consists primarily of two phases, both of which contain Am: ζ-(U, Np, Pu, Am) (~70 at% U, 5% Np, 14% Pu, 1% Am, and 10% Zr) and δ-(U, Np, Pu, Am)Zr 2 (~25% U, 2% Np, 10-15% Pu, 1-2% Am, and 55-60 at% Zr). These phases are similar to those in U-Pu-Zr alloys, although the Zr content in ζ-(U, Np, Pu, Am) is higher than that in ζ-(U, Pu)more » and the Zr content in δ-(U, Np, Pu, Am)Zr 2 is lower than that in δ-UZr 2. Nanocrystalline actinide oxides with structures similar to UO2 occurred in some areas, but may have formed by reactions with the atmosphere during sample handling. Planar features consisting of a central zone of ζ-(U, Np, Pu, Am) bracketed by zones of δ-(U, Np, Pu, Am)Zr 2 bound irregular polygons ranging in size from a few micrometers to a few tens of micrometers across. The rest of the matrix consists of elongated domains of ζ-(U, Np, Pu, Am) and δ-(U, Np, Pu, Am)Zr 2. Each of these domains is a few tens of nanometers across and a few hundred nanometers long. The domains display strong preferred orientations involving areas a few hundred nanometers to a few micrometers across.« less

  11. Geochemical evidence for mixing of three components in martian orthopyroxenite ALH 84001. [Abstract only

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.; Lindstrom, M. M.

    1994-01-01

    ALH 84001, a ferroan martian orthopyroxenite, originally consisted of three petrographically defined components: a cumulus assemblage of orthopyroxene + chromite, a trapped melt assemblage of orthopyroxene(?) + chromite + maskelynite + apatite + augite +/- pyrite, and a metasomatic assemblage of carbonate +/- pyrite. We present the results of Instrumental Neutron Activation Analysis (INAA) study of five bulk samples of ALH 84001, combined with Scanning Ion Mass Spectrometer (SIMS) data on the orthopyroxene, in order to attempt to set limits on the geochemical characteristics of the latter two components, and therefore on the petrogenesis of ALH 84001. The INAA data support the petrographic observations, suggesting that there are at least three components in ALH 84001. We will assume that each of the three geochemically required components can be equated with one of the petrographically observed components. Both trapped melt and metasomatic components in ALH 84001 have higher Na than orthopyroxene based on compositions of maskelynite, apatite, and carbonate. For the metasomatic component, we will assume its Na content is that of carbonate, while for a trapped melt component, we will use a typical Na content inferred for martian meteorite parent melts, approximately 1 wt% Na2O. Under these assumptions, we can set limits on the Light Rare Earth Elements/Heavy Rare Earth Elements (LREE/HREE) ratios of the components, and use this information to compare the petrogenesis of ALH 84001 with other martian meteorites. The above calculations assume that the bulk samples are representative of different portions of ALH 84001. We will also evaluate the possible heterogeneous distribution of mineral phases in the bulk samples as the cause of compositional heterogeneity in our samples.

  12. Effect of some light rare earth elements on seed germination, seedling growth and antioxidant metabolism in Triticum durum.

    PubMed

    d'Aquino, Luigi; de Pinto, Maria Concetta; Nardi, Luca; Morgana, Massimo; Tommasi, Franca

    2009-05-01

    Rare earth elements (REEs) enriched fertilizers have been commonly used in China since the 1980s, thus inducing a growing concern about their environmental impact in agriculture. In this work, the effect of some light REEs nitrate mixture and La(3+) nitrate on seed germination, seedling growth and antioxidant metabolism in Triticum durum was investigated with the aim of clarifying the potential benefits or damages of REEs on plants. Seed pre-soaking for 8 h with La(3+) and REEs nitrate inhibited seed germination at low concentrations (0.01 mM and 0.1 mM), while pre-soaking for 2 and 4 h already inhibited seed germination when higher concentrations (1 mM and 10 mM) of La(3+) and REEs nitrate were used. La(3+) and REEs nitrate treatment also affected seedling growth. Root growth was enhanced and inhibited at low and high concentrations, respectively. Shoot growth was inhibited by La(3+) and REEs nitrate at all tested concentrations after 12 d of treatments. Enzymatic and non enzymatic antioxidants were differently affected by La(3+) and REEs nitrate and their behaviour changed also depending on the plant organ. In roots La(3+) and REEs nitrate treatments induced an increase in ascorbate (ASC) and glutathione (GSH) contents. In shoots only La(3+) nitrate induced an increase in the ASC content whereas GSH decreased following both La(3+) and REEs nitrate treatments. An increase in ASC peroxidase activity was observed in shoots and roots, while catalase did not change in roots and slightly decreased in shoots. The possible role of the increase in some antioxidants as indicators of stress caused by lanthanide treatments is discussed.

  13. Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia

    DOE PAGES

    Keegan, Elizabeth; Kristo, Michael J.; Colella, Michael; ...

    2014-04-13

    In early 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. While searching the laboratory, they discovered a small glass jar labelled “Gamma Source” and containing a green powder. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterize and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive rangemore » of parameters were measured, the key ‘nuclear forensic signatures’ used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine.« less

  14. Microelements in anthropogenically contaminated soils in the central part of Petrozavodsk

    NASA Astrophysics Data System (ADS)

    Rybakov, D. S.; Kevlich, V. I.

    2017-06-01

    Urban soils (Urbic Technosols) formed within or near the industrial sites removed of service show a considerable excess over the regional background in the content of Pb, Zn, Cu, Mn, Cr, Ni, as well as over the average content of W, Mo, Pb, Sb, Cr, Cu, Sn, Ni, Zn, and Mn in urban soils. Microelements are concentrated for the most part in the soil fine earth, and above all, in the fraction with particle size <0.1 mm. Surface films (on quartz and feldspar grains) of quartz-feldspar-muscovite (partially with tremolite and chlorite) composition and undifferentiated dispersed mixture of quartz, albite, microcline, muscovite and organomineral soil substance are the strongest concentrators of heavy metals and metalloids. Pb and Sn are partially present in soils as oxides, and a part of Zn and Pb, in the form of substantial admixtures to technogenic chemical compounds. As a whole, distribution of elements in the studied soils is controlled by the specifics and type of contamination, resistance of coarser grains to weathering under the given physicochemical conditions, and by predominantly mineral (quartz-feldspar) composition of the solids in soil layers and the features of elements proper.

  15. Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia.

    PubMed

    Keegan, Elizabeth; Kristo, Michael J; Colella, Michael; Robel, Martin; Williams, Ross; Lindvall, Rachel; Eppich, Gary; Roberts, Sarah; Borg, Lars; Gaffney, Amy; Plaue, Jonathan; Wong, Henri; Davis, Joel; Loi, Elaine; Reinhard, Mark; Hutcheon, Ian

    2014-07-01

    Early in 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. During the search of the laboratory, a small glass jar labelled "Gamma Source" and containing a green powder was discovered. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterise and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive range of parameters were measured, the key 'nuclear forensic signatures' used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  16. Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Keegan, Elizabeth; Kristo, Michael J.; Colella, Michael

    In early 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. While searching the laboratory, they discovered a small glass jar labelled “Gamma Source” and containing a green powder. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterize and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive rangemore » of parameters were measured, the key ‘nuclear forensic signatures’ used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine.« less

  17. Phase relations of Fe-Si-Ni alloys at core conditions: Implications for the Earth inner core

    NASA Astrophysics Data System (ADS)

    Fiquet, G.; Boulard, E.; Auzende, A.; Antonangeli, D.; Badro, J.; Morard, G.; Siebert, J.; Perrillat, J.; Mezouar, M.

    2008-12-01

    The Earth core consists of a liquid outer core and a solid inner core, which are believed to be made predominantly of iron (Fe). Among all crystallographic structures proposed, a consensus has more or less emerged with the hexagonal closed packed structure -hcp- for iron. The question of the structure of this alloy at core conditions, in particular in vicinity of the melting line is however still largely debated. Among others, a possible thermal and chemical stabilization of body-centered cubic iron in the Earth's core has indeed been proposed with the theoretical calculations of Vocadlo et al. [Nature, 424, 536, 2003]. Recent X-ray experiments have shown the existence of such a bcc structure above 220 GPa at high-temperature for iron- nickel alloys [Dubrovinsky et al., Science, 316, 1880, 2007]. It is also known from density systematics that the Earth's core is made of iron alloyed with light elements [see Poirier, Phys. Earth Planet. Int., 85, 319, 1994]. We recently proposed a compositional model for the Earth's inner core from a systematic study of the effect of light elements on sound velocities at high pressure. Our preferred core model is an inner core which contains 2.3 wt % silicon and traces of oxygen [see Badro et al., Earth Planet. Sci. Lett., 254, 233, 2007 for more details]. Recent studies, however, suggest that small amount of silicon or nickel can substantially affect the phase relations and thermodynamic properties of iron alloys. We present results from an X-ray diffraction carried out at ESRF at high-pressure and high-temperature, using a state-of-the-art double sided laser heating system. We address the question of the structure of this alloy at core conditions. Two different alloys have been synthesized for this experiment, with Fe : 92.4, Si : 3.7, Ni 3.9 and Fe: 88.4, Si: 7.3, Ni: 4.3 in wt %, so as to satisfy the core preferred compositional model described in Badro et al. [2007]. The samples were loaded in a diamond anvil cell with neon as pressure transmitting medium transmitting medium, and subsequently analyzed by diffraction collected on a CCD detector during laser-heating at pressure. Experiments were carried out between 20 and 200 GPa, and 1500-5000 K. Our results show an increase of the pressure transition from bcc to hcp with increasing silicon content, with much more precise pressure transitions than previously published. X-ray diffraction pattern contain fcc or hcp at high-temperature and high-pressure conditions. If an expansion of the fcc stability field is observed with increasing silicon and/or nickel content, our observations show a wide stability of hcp-iron alloys up to 200 GPa and high-temperature. These results are discussed in the light of recent experimental and theoretical investigations.

  18. Do Interactive Globes and Games Help Students Learn Planetary Science?

    NASA Astrophysics Data System (ADS)

    Coba, Filis; Burgin, Stephen; De Paor, Declan; Georgen, Jennifer

    2016-01-01

    The popularity of animations and interactive visualizations in undergraduate science education might lead one to assume that these teaching aids enhance student learning. We tested this assumption for the case of the Google Earth virtual globe with a comparison of control and treatment student groups in a general education class of over 370 students at a large public university. Earth and Planetary Science course content was developed in two formats: using Keyhole Markup Language (KML) to create interactive tours in Google Earth (the treatment group) and Portable Document Format (PDF) for on-screen reading (the control group). The PDF documents contained identical text and images to the placemark balloons or "tour stops" in the Google Earth version. Some significant differences were noted between the two groups based on the immediate post-questionnaire with the KML students out-performing the PDF students, but not on the delayed measure. In a separate but related project, we undertake preliminary investigations into methods of teaching basic concepts in planetary mantle convection using numerical simulations. The goal of this project is to develop an interface with a two-dimensional finite element model that will allow students to vary parameters such as the temperatures assigned to the boundaries of the model domain, to help them actively explore important variables that control convection.

  19. Techno-Economic Assessment for Integrating Biosorption into Rare Earth Recovery Process

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jiao, Yongqin; Sutherland, John; Jin, Hongyue

    The current uncertainty in the global supply of rare earth elements (REEs) necessitates the development of novel extraction technologies that utilize a variety of REE source materials. Herein, we examined the techno-economic performance of integrating a biosorption approach into a large-scale process for producing salable total rare earth oxides (TREOs) from various feedstocks. An airlift bioractor is proposed to carry out a biosorption process mediated by bioengineered rare earth-adsorbing bacteria. Techno-econmic asssements were compared for three distinctive categories of REE feedstocks requiring different pre-processing steps. Key parameters identified that affect profitability include REE concentration, composition of the feedstock, and costsmore » of feedstock pretreatment and waste management. Among the 11 specific feedstocks investigated, coal ash from the Appalachian Basin was projected to be the most profitable, largely due to its high-value REE content. Its cost breakdown includes pre-processing (primarily leaching) (8077.71%), biosorption (1619.04%), and oxalic acid precipitation and TREO roasting (3.35%). Surprisingly, biosorption from the high-grade Bull Hill REE ore is less profitable due to high material cost and low production revenue. Overall, our results confirmed that the application of biosorption to low-grade feedstocks for REE recovery is economically viable.« less

  20. Cerium-based, intermetallic-strengthened aluminum casting alloy: High-volume co-product development

    DOE PAGES

    Sims, Zachary C.; Weiss, David; McCall, S. K.; ...

    2016-05-23

    Here, several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanicalmore » properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic.« less

  1. Electrical and thermal conductivity of Fe-C alloy at high pressure: implications for effects of carbon on the geodynamo of the Earth's core

    NASA Astrophysics Data System (ADS)

    Zhang, C.; Lin, J. F.; Liu, Y.; Feng, S.; Jin, C.; Yoshino, T.

    2017-12-01

    Thermal conductivity of iron alloy in the Earth's core plays a crucial role in constraining the energetics of the geodynamo and the thermal evolution of the planet. Studies on the thermal conductivity of iron reveal the importance of the effects of light elements and high temperature. Carbon has been proposed to be a candidate light element in Earth's core for its meteoritic abundance and high-pressure velocity-density profiles of iron carbides (e.g., Fe7C3). In this study, we employed four-probe van der Pauw method in a diamond anvil cell to measure the electrical resistivity of pure iron, iron carbon alloy, and iron carbides at high pressures. These studies were complimented with synchrotron X-ray diffraction and focused ion beam (FIB) analyses. Our results show significant changes in the electrical conductivity of these iron-carbon alloys that are consistent previous reports with structural and electronic transitions at high pressures, indicating that these transitions should be taken into account in evaluating the electrical and thermal conductivity at high pressure. To apply our results to understand the thermal conduction in the Earth's core, we have compared our results with literature values for the electrical and thermal conductivity of iron alloyed with light elements (C, Si) at high pressures. These comparisons permit the validity of the Wiedemann-Franz law and Matthiessen's rule for the effects of light elements on the thermal conductivity of the Earth's core. We found that an addition of a light element such as carbon has an strong effect on the reducing the thermal conductivity of Earth's core, but the magnitude of the alloying effect strongly depends on the identity of the light element and the crystal and electronic structures. Based on our results and literature values, we have modelled the electrical and thermal conductivity of iron-carbon alloy at Earth's core pressure-temperature conditions to the effects on the heat flux in the Earth's core. In this presentation, we will address how carbon as a potential light element in the Earth's core can significantly affect our view of the heat flux across the core-mantle boundary and geodynamo of our planet.

  2. Global occurrence of tellurium-rich ferromanganese crusts and a model for the enrichment of tellurium

    USGS Publications Warehouse

    Hein, J.R.; Koschinsky, A.; Halliday, A.N.

    2003-01-01

    Hydrogenetic ferromanganese oxyhydroxide crusts (Fe-Mn crusts) precipitate out of cold ambient ocean water onto hard-rock surfaces (seamounts, plateaus, ridges) at water depths of about 400 to 4000 m throughout the ocean basins. The slow-growing (mm/Ma) Fe-Mn crusts concentrate most elements above their mean concentration in the Earth's crust. Tellurium is enriched more than any other element (up to about 50,000 times) relative to its Earth's crustal mean of about 1 ppb, compared with 250 times for the next most enriched element. We analyzed the Te contents for a suite of 105 bulk hydrogenetic crusts and 140 individual crust layers from the global ocean. For comparison, we analyzed 10 hydrothermal stratabound Mn-oxide samples collected from a variety of tectonic environments in the Pacific. In the Fe-Mn crust samples, Te varies from 3 to 205 ppm, with mean contents for Pacific and Atlantic samples of about 50 ppm and a mean of 39 ppm for Indian crust samples. Hydrothermal Mn samples have Te contents that range from 0.06 to 1 ppm. Continental margin Fe-Mn crusts have lower Te contents than open-ocean crusts, which is the result of dilution by detrital phases and differences in growth rates of the hydrogenetic phases. Correlation coefficient matrices show that for hydrothermal deposits, Te has positive correlations with elements characteristic of detrital minerals. In contrast, Te in open-ocean Fe-Mn crusts usually correlates with elements characteristic of the MnO2, carbonate fluorapatite, and residual biogenic phases. In continental margin crusts, Te also correlates with FeOOH associated elements. In addition, Te is negatively correlated with water depth of occurrence and positively correlated with crust thickness. Q-mode factor analyses support these relationships. However, sequential leaching results show that most of the Te is associated with FeOOH in Fe-Mn crusts and ???10% is leached with the MnO2. Thermodynamic calculations indicate that Te occurs predominantly as H5TeO6- in ocean water. The speciation of Te in ocean water and charge balance considerations indicate that Te should be scavenged by FeOOH, which is in agreement with our leaching results. The thermodynamically more stable Te(IV) is less abundant by factors of 2 to 3.5 than Te(VI) in ocean water. This can be explained by preferential (not exclusive) scavenging of Te(IV) by FeOOH at the Fe-Mn crust surface and by Fe-Mn colloids in the water column. We propose a model in which the extreme enrichment of Te in Fe-Mn crusts is likely the result of an oxidation reaction on the surface of FeOOH. A similar oxidation process has been confirmed for Co, Ce, and Tl at the surface of MnO2 in crusts, but has not been suggested previously to occur in association with FeOOH in Fe-Mn crusts. Mass-balance considerations indicate that ocean floor Fe-Mn deposits are the major sink for Te in the oceans. The concentration and redox chemistry of Te in the global ocean are likely controlled by scavenging on Fe-Mn colloids in the water column and Fe-Mn deposits on the ocean floor, as is also the case for Ce. ?? 2003 Elsevier Science Ltd.

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

    PubMed

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

    2014-02-01

    The phytotoxicity of rare earth elements (REEs) is still poorly understood. The exposure-response relationships of three native Canadian plant species (common milkweed, Asclepias syriaca L., showy ticktrefoil, Desmodium canadense (L.) DC. and switchgrass, Panicum virgatum L.) and two commonly used crop species (radish, Raphanus sativus L., and tomato, Solanum lycopersicum L.) to the REEs lanthanum (La), yttrium (Y) and cerium (Ce) were tested. In separate experiments, seven to eight doses of each element were added to the soil prior to sowing seeds. Effects of REE dose on germination were established through measures of total percent germination and speed of germination; effects on growth were established through determination of above ground biomass. Ce was also tested at two pH levels and plant tissue analysis was conducted on pooled samples. Effects on germination were mostly observed with Ce at low pH. However, effects on growth were more pronounced, with detectable inhibition concentrations causing 10% and 25% reductions in biomass for the two native forb species (A. syriaca and D. canadense) with all REEs and on all species tested with Ce in both soil pH treatments. Concentration of Ce in aboveground biomass was lower than root Ce content, and followed the dose-response trend. From values measured in natural soils around the world, our results continue to support the notion that REEs are of limited toxicity and not considered extremely hazardous to the environment. However, in areas where REE contamination is likely, the slow accumulation of these elements in the environment could become problematic. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Eocene slab breakoff of Neotethys as suggested by dioritic dykes in the Gangdese magmatic belt, southern Tibet

    NASA Astrophysics Data System (ADS)

    Ma, Xuxuan; Xu, Zhiqin; Meert, Joseph G.

    2016-04-01

    The Gangdese magmatic belt in southern Tibet demarcates an important boundary between the Indian and Eurasian plates. Due to its location and magmatic evolutionary history, it is key to understanding both the history of Neotethys closure and the Indo-Asian collisional process. This study presents new geochronological and geochemical data for dioritic dykes in the southern Gangdese magmatic belt in southern Tibet. U-Pb geochronological results reveal that the dykes were emplaced at ca. 41 Ma and thus broadly coeval with the 40-38 Ma Dazi volcanics and the 42-40 Ma Gaoligong-Tengliang basaltic dykes. Geochemically, these dykes are characterized by alkaline signature, high Mg# (57-63) and low TiO2 contents ( 0.9-1.0), showing notable enrichment of light rare earth elements relative to the heavy rare earth elements, enrichment of incompatible elements (i.e. Cs, Rb, Ba, Th and U), and depletion of high field strength elements (i.e. Nb, Ta and Ti). In addition, a large variation of zircon εHf(t) values (- 10 to + 13) was shown, implying heterogeneity of magma sources. A heterogeneous source is also suggested by the occurrence of xenocrysts in the dykes. These observations suggest that the magma source of the dykes was dominated by partial melting of lithospheric mantle and then subsequently contaminated by crustal material during ascent. In combination with other geological data in the region, we suspect that the slab slicing of the Neotethys played a key role in the formation of the lithospheric mantle-derived dioritic dykes and adakitic granite, asthenosphere-derived volcanics, basaltic dykes, as well as the recently reported strongly fractionated granites.

  5. Chemical Sample Processing for Combined Selenium Isotope and Selenium-Tellurium Elemental Investigation of the Earth's Igneous Reservoirs

    NASA Astrophysics Data System (ADS)

    Yierpan, Aierken; König, Stephan; Labidi, Jabrane; Kurzawa, Timon; Babechuk, Michael G.; Schoenberg, Ronny

    2018-02-01

    The redox-sensitive, chalcophile, and volatile Se stable isotope system offers new perspectives to investigate the origin and evolution of terrestrial volatiles and the roles of magmatic and recycling processes in the development of the redox contrast between Earth's reservoirs. Selenium isotope systematics become more robust in a well-constrained petrogenetic context as can be inferred from Se-Te elemental signatures of sulfides and igneous rocks. In this study, we present a high-yield chemical sample processing method that allows the determination of Se-Te concentrations and Se isotope composition from the same sample digest of silicate rocks by hydride generation isotope dilution (ID) quadrupole inductively coupled plasma mass spectrometry (ICP-MS) and double spike (DS) multicollector (MC)-ICP-MS, respectively. Our procedure yields ˜80% Se-Te recoveries with quantitative separation of relevant interfering elements such as Ge and HG-buffering metals. Replicate analyses of selected international reference materials yield uncertainties better than 0.11‰ (2 s.d.) on δ82/76Se and 3% (r.s.d.) on Se concentration for DS MC-ICP-MS determinations for as low as ˜10 ng sample Se. The precision of Se-Te concentration measurements by ID ICP-MS is better than 3% and 5% (r.s.d.) for total amounts of ˜0.5-1 ng Se and ˜0.2-0.5 ng Te, respectively. The basaltic reference materials have variable Se-Te contents, but their δ82/76Se values are rather uniform (on average 0.23 ± 0.14‰; 2 s.d.) and different from the chondritic value. This altogether provides the methodology and potential to extend the limited data set of coupled Se isotope and Se-Te elemental systematics of samples relevant to study the terrestrial igneous inventory.

  6. Earth Observatory Satellite system definition study. Report no. 5: System design and specifications. Part 1: Observatory system element specifications

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The performance, design, and quality assurance requirements for the Earth Observatory Satellite (EOS) Observatory and Ground System program elements required to perform the Land Resources Management (LRM) A-type mission are presented. The requirements for the Observatory element with the exception of the instruments specifications are contained in the first part.

  7. Understanding the Role of Biology in the Global Environment: NASA'S Mission to Planet Earth

    NASA Technical Reports Server (NTRS)

    Townsend, William F.

    1996-01-01

    NASA has long used the unique perspective of space as a means of expanding our understanding of how the Earth's environment functions. In particular, the linkages between land, air, water, and life-the elements of the Earth system-are a focus for NASA's Mission to Planet Earth. This approach, called Earth system science, blends together fields like meteorology, biology, oceanography, and atmospheric science. Mission to Planet Earth uses observations from satellites, aircraft, balloons, and ground researchers as the basis for analysis of the elements of the Earth system, the interactions between those elements, and possible changes over the coming years and decades. This information is helping scientists improve our understanding of how natural processes affect us and how we might be affecting them. Such studies will yield improved weather forecasts, tools for managing agriculture and forests, information for fishermen and local planners, and, eventually, an enhanced ability to predict how the climate will change in the future. NASA has designed Mission to Planet Earth to focus on five primary themes: Land Cover and Land Use Change; Seasonal to Interannual Climate Prediction; Natural Hazards; Long-Term Climate Variability; and Atmosphere Ozone.

  8. Chemical element accumulation in tree bark grown in volcanic soils of Cape Verde-a first biomonitoring of Fogo Island.

    PubMed

    Marques, Rosa; Prudêncio, Maria Isabel; Freitas, Maria do Carmo; Dias, Maria Isabel; Rocha, Fernando

    2017-05-01

    Barks from Prosopis juliflora (acacia) were collected in 12 sites of different geological contexts over the volcanic Fogo Island (Cape Verde). Elemental contents of Ba, Br, Co, Cr, Fe, K, Na, Zn and some rare earth elements (REE)-La, Ce, Sm, Eu, Tb, Yb, and Lu, were obtained for biological samples and topsoils by using k 0 -standardized and comparative method of instrumental neutron activation analysis (INAA), aiming the evaluation of chemical elements uptake by acacia bark. This first biomonitoring study of Fogo Island showed that, in general, significant accumulations of trace elements present in high amounts in these soils occur. This can be partially explained by the semi-arid climate with a consequent bioavailability of chemical elements when rain drops fall in this non-polluted environment. REE enrichment factors (EFs) increase with the decrease of ionic radius. Heavy REE (HREE) are significantly enriched in bark, which agrees with their release after the primary minerals breakdown and the formation of more soluble compounds than the other REE, and uptake by plants. Among the potential harmful chemical elements, Cr appears to be partially retained in nanoparticles of iron oxides. The high EFs found in tree barks of Fogo Island are certainly of geogenic origin rather than anthropogenic input since industry and the use of fertilizers is scarce.

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

    NASA Astrophysics Data System (ADS)

    Agustawijaya, Didi Supriadi; Karyadi, Karyadi; Krisnayanti, Baiq Dewi; Sutanto, Sutanto

    2017-12-01

    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.

  10. Method of determining lanthanidies in a transition element host

    DOEpatents

    De Kalb, Edward L.; Fassel, Velmer A.

    1976-02-03

    A phosphor composition contains a lanthanide activator element within a host matrix having a transition element as a major component. The host matrix is composed of certain rare earth phosphates or vanadates such as YPO.sub.4 with a portion of the rare earth replaced with one or more of the transition elements. On X-ray or other electromagnetic excitation, trace lanthanide impurities or additives within the phosphor are spectrometrically determined from their characteristic luminescence.

  11. Global-scale water circulation in the Earth's mantle: Implications for the mantle water budget in the early Earth

    NASA Astrophysics Data System (ADS)

    Nakagawa, Takashi; Spiegelman, Marc W.

    2017-04-01

    We investigate the influence of the mantle water content in the early Earth on that in the present mantle using numerical convection simulations that include three processes for redistribution of water: dehydration, partitioning of water into partially molten mantle, and regassing assuming an infinite water reservoir at the surface. These models suggest that the water content of the present mantle is insensitive to that of the early Earth. The initial water stored during planetary formation is regulated up to 1.2 OMs (OM = Ocean Mass; 1.4 ×1021 kg), which is reasonable for early Earth. However, the mantle water content is sensitive to the rheological dependence on the water content and can range from 1.2 to 3 OMs at the present day. To explain the evolution of mantle water content, we computed water fluxes due to subducting plates (regassing), degassing and dehydration. For weakly water dependent viscosity, the net water flux is almost balanced with those three fluxes but, for strongly water dependent viscosity, the regassing dominates the water cycle system because the surface plate activity is more vigorous. The increased convection is due to enhanced lubrication of the plates caused by a weak hydrous crust for strongly water dependent viscosity. The degassing history is insensitive to the initial water content of the early Earth as well as rheological strength. The degassing flux from Earth's surface is calculated to be approximately O (1013) kg /yr, consistent with a coupled model of climate evolution and mantle thermal evolution.

  12. Addressing Rare-Earth Element Criticality: An Example from the Aviation Industry

    NASA Astrophysics Data System (ADS)

    Ku, Anthony Y.; Dosch, Christopher; Grossman, Theodore R.; Herzog, Joseph L.; Maricocchi, Antonio F.; Polli, Drew; Lipkin, Don M.

    2014-11-01

    Rare-earth (RE) elements are enablers for a wide range of technologies, including high-strength permanent magnets, energy-efficient lighting, high-temperature thermal barrier coatings, and catalysts. While direct material substitution is difficult in many of these applications because of the specific electronic, optical, or electrochemical properties imparted by the individual rare-earth elements, we describe an example from the aviation industry where supply chain optimization may be an option. Ceramic matrix composite engine components require environmental barrier coatings (EBCs) to protect them from extreme temperatures and adverse reactions with water vapor in the hot gas path. EBC systems based on rare-earth silicates offer a unique combination of environmental resistance, thermal expansion matching, thermal conductivity, and thermal stability across the service temperature window. Several pure rare-earth silicates and solid solutions have been demonstrated in EBC applications. However, all rely on heavy rare-earth elements (HREEs) for phase stability. This article considers the possibility of using separation tailings containing a mixture of HREEs as a source material in lieu of using the high-purity HREE oxides. This option arises because the desired properties of RE-silicate EBCs derive from the average cation size rather than the electronic properties of the individual rare-earth cations. Because separation tailings have not incurred the costs associated with the final stages of separation, they offer an economical alternative to high-purity oxides for this emerging application.

  13. Initial blood storage experiment

    NASA Technical Reports Server (NTRS)

    Surgenor, Douglas MACN.

    1988-01-01

    The possibility of conducting experiments with the formed elements of the blood under conditions of microgravity opens up important opportunities to improve the understanding of basic formed element physiology, as well as, contribution to improved preservation of the formed elements for use in transfusion. The physiological, biochemical, and physical changes of the membrane of the erythrocyte, platelet, and leukocyte was studied during storage under two specific conditions: standard blood bank conditions and microgravity, utilizing three FDA approved plastic bags. Storage lesions; red cell storage on Earth; platelet storage on Earth; and leukocyte storage Earth were examined. The interaction of biomaterials and blood cells was studied during storage.

  14. Modelling of charged satellite motion in Earth's gravitational and magnetic fields

    NASA Astrophysics Data System (ADS)

    Abd El-Bar, S. E.; Abd El-Salam, F. A.

    2018-05-01

    In this work Lagrange's planetary equations for a charged satellite subjected to the Earth's gravitational and magnetic force fields are solved. The Earth's gravity, and magnetic and electric force components are obtained and expressed in terms of orbital elements. The variational equations of orbit with the considered model in Keplerian elements are derived. The solution of the problem in a fully analytical way is obtained. The temporal rate of changes of the orbital elements of the spacecraft are integrated via Lagrange's planetary equations and integrals of the normalized Keplerian motion obtained by Ahmed (Astron. J. 107(5):1900, 1994).

  15. Polymer monolithic capillary microextraction combined on-line with inductively coupled plasma MS for the determination of trace rare earth elements in biological samples.

    PubMed

    Zhang, Lin; Chen, Beibei; He, Man; Hu, Bin

    2013-07-01

    A rapid and sensitive method based on polymer monolithic capillary microextraction combined on-line with microconcentric nebulization inductively coupled plasma MS has been developed for the determination of trace/ultratrace rare earth elements in biological samples. For this purpose, the iminodiacetic acid modified poly(glycidyl methacrylate-trimethylolpropane trimethacrylate) monolithic capillary was prepared and characterized by SEM and FTIR spectroscopy. Factors affecting the extraction efficiency, such as sample pH, sample flow rate, sample/eluent volume, and coexisting ions were investigated in detail. Under the optimal conditions, the LODs for rare earth elements were in the range of 0.08 (Er) to 0.97 ng/L (Nd) with a sampling frequency of 8.5 h(-1), and the RSDs were between 1.5% (Sm) and 7.4% (Nd) (c = 20 ng/L, n = 7). The proposed method was successfully applied to the analysis of trace/ultratrace rare earth elements in human urine and serum samples, and the recoveries for the spiked samples were in the range of 82-105%. The developed method was simple, rapid, sensitive, and favorable for the analysis of trace/ultratrace rare earth elements in biological samples with limited sample volume. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Environmental Defects And Economic Impact On Global Market Of Rare Earth Metals

    NASA Astrophysics Data System (ADS)

    Charalampides, G.; Vatalis, K.; Karayannis, V.; Baklavaridis, A.

    2016-11-01

    Rare earth elements include the 14 lanthanides as well as lanthanium and often yttrium. Actually, most of them are not very rare and occur widely dispersed in a variety of rocks. Rare earth metals are vital to some of the world's faster growing industries: catalysts, Nd-magnets, ceramics, glass, metallurgy, battery alloys, electronics and phosphors. Worldwide, the main countries for distribution of rare earths deposits include China, USA, Russia, Brasil, India, Australia, Greenland and Malaysia. The mining and processing of rare earth metals usually result in significant environmental defects. Many deposits are associated with high concentrations of radioactive elements such as uranium and thorium, which requires separate treatment and disposal. The accumulation of rare earth elements in soils has occurred due to pollution caused by the exploitation of rare earth resources and the wide use of rare earths as fertilizers in agriculture. This accumulation has a toxic effect on the soil microfauna community. However, there are large differences in market prices due to the degree of purity determined by the specifications in the applications. The main focus of this article is to overview Rare Earth Metals’ overall impact on global economy and their environmental defects on soils during processing techniques and as they are used as fertilizers.

  17. Zinc isotope evidence for sulfate-rich fluid transfer across subduction zones.

    PubMed

    Pons, Marie-Laure; Debret, Baptiste; Bouilhol, Pierre; Delacour, Adélie; Williams, Helen

    2016-12-16

    Subduction zones modulate the chemical evolution of the Earth's mantle. Water and volatile elements in the slab are released as fluids into the mantle wedge and this process is widely considered to result in the oxidation of the sub-arc mantle. However, the chemical composition and speciation of these fluids, which is critical for the mobility of economically important elements, remain poorly constrained. Sulfur has the potential to act both as oxidizing agent and transport medium. Here we use zinc stable isotopes (δ 66 Zn) in subducted Alpine serpentinites to decipher the chemical properties of slab-derived fluids. We show that the progressive decrease in δ 66 Zn with metamorphic grade is correlated with a decrease in sulfur content. As existing theoretical work predicts that Zn-SO 4 2- complexes preferentially incorporate heavy δ 66 Zn, our results provide strong evidence for the release of oxidized, sulfate-rich, slab serpentinite-derived fluids to the mantle wedge.

  18. [Spectroscopic Research on Slag Nanocrystal Glass Ceramics Containing Rare Earth Elements].

    PubMed

    Ouyang, Shun-li; Li, Bao-wei; Zhang, Xue-feng; Jia, Xiao-lin; Zhao, Ming; Deng, Lei-bo

    2015-08-01

    The research group prepared the high-performance slag nanocrystal glass ceramics by utilizing the valuable elements of the wastes in the Chinese Bayan Obo which are characterized by their symbiotic or associated existence. In this paper, inductively coupled plasma emission spectroscopy (ICP), X-ray diffraction (XRD), Raman spectroscopy (Raman) and scanning electron microscopy (SEM) are all used in the depth analysis for the composition and structure of the samples. The experiment results of ICP, XRD and SEM showed that the principal crystalline phase of the slag nanocrystal glass ceramics containing rare earth elements is diopside, its grain size ranges from 45 to 100 nm, the elements showed in the SEM scan are basically in consistent with the component analysis of ICP. Raman analysis indicated that its amorphous phase is a three-dimensional network structure composed by the structural unit of silicon-oxy tetrahedron with different non-bridging oxygen bonds. According to the further analysis, we found that the rare earth microelement has significant effect on the network structure. Compared the nanocrystal slag glass ceramic with the glass ceramics of similar ingredients, we found that generally, the Raman band wavenumber for the former is lower than the later. The composition difference between the glass ceramics and the slag nanocrystal with the similar ingredients mainly lies on the rare earth elements and other trace elements. Therefore, we think that the rare earth elements and other trace elements remains in the slag nanocrystal glass ceramics have a significant effect on the network structure of amorphous phase. The research method of this study provides an approach for the relationship among the composition, structure and performance of the glass ceramics.

  19. Cosmochemical Estimates of Mantle Composition

    NASA Astrophysics Data System (ADS)

    Palme, H.; O'Neill, H. St. C.

    2003-12-01

    In 1794 the German physicist Chladni published a small book in which he suggested the extraterrestrial origin of meteorites. The response was skepticism and disbelief. Only after additional witnessed falls of meteorites did scientists begin to consider Chladni's hypothesis seriously. The first chemical analyses of meteorites were published by the English chemist Howard in 1802, and shortly afterwards by Klaproth, a professor of chemistry in Berlin. These early investigations led to the important conclusion that meteorites contained the same elements that were known from analyses of terrestrial rocks. By the year 1850, 18 elements had been identified in meteorites: carbon, oxygen, sodium, magnesium, aluminum, silicon, phosphorous, sulfur, potassium, calcium, titanium, chromium, manganese, iron, cobalt, nickel, copper, and tin (Burke, 1986). A popular hypothesis, which arose after the discovery of the first asteroid Ceres on January 1, 1801 by Piazzi, held that meteorites came from a single disrupted planet between Mars and Jupiter. In 1847 the French geologist Boisse (1810-1896) proposed an elaborate model that attempted to account for all known types of meteorites from a single planet. He envisioned a planet with layers in sequence of decreasing densities from the center to the surface. The core of the planet consisted of metallic iron surrounded by a mixed iron-olivine zone. The region overlying the core contained material similar to stony meteorites with ferromagnesian silicates and disseminated grains of metal gradually extending into shallower layers with aluminous silicates and less iron. The uppermost layer consisted of metal-free stony meteorites, i.e., eucrites or meteoritic basalts. About 20 years later, Daubrée (1814-1896) carried out experiments by melting and cooling meteorites. On the basis of his results, he came to similar conclusions as Boisse, namely that meteorites come from a single, differentiated planet with a metal core, a silicate mantle, and a crust. Both Daubrée and Boisse also expected that the Earth was composed of a similar sequence of concentric layers (see Burke, 1986; Marvin, 1996).At the beginning of the twentieth century Harkins at the University of Chicago thought that meteorites would provide a better estimate for the bulk composition of the Earth than the terrestrial rocks collected at the surface as we have only access to the "mere skin" of the Earth. Harkins made an attempt to reconstruct the composition of the hypothetical meteorite planet by compiling compositional data for 125 stony and 318 iron meteorites, and mixing the two components in ratios based on the observed falls of stones and irons. The results confirmed his prediction that elements with even atomic numbers are more abundant and therefore more stable than those with odd atomic numbers and he concluded that the elemental abundances in the bulk meteorite planet are determined by nucleosynthetic processes. For his meteorite planet Harkins calculated Mg/Si, Al/Si, and Fe/Si atomic ratios of 0.86, 0.079, and 0.83, very closely resembling corresponding ratios of the average solar system based on presently known element abundances in the Sun and in CI-meteorites (see Burke, 1986).If the Earth were similar compositionally to the meteorite planet, it should have a similarly high iron content, which requires that the major fraction of iron is concentrated in the interior of the Earth. The presence of a central metallic core to the Earth was suggested by Wiechert in 1897. The existence of the core was firmly established using the study of seismic wave propagation by Oldham in 1906 with the outer boundary of the core accurately located at a depth of 2,900km by Beno Gutenberg in 1913. In 1926 the fluidity of the outer core was finally accepted. The high density of the core and the high abundance of iron and nickel in meteorites led very early to the suggestion that iron and nickel are the dominant elements in the Earth's core (Brush, 1980; see Chapter 2.15).Goldschmidt (1922) introduced his zoned Earth model. Seven years later he published details ( Goldschmidt, 1929). Goldschmidt thought that the Earth was initially completely molten and separated on cooling into three immiscible liquids, leading on solidification to the final configuration of a core of FeNi which was overlain by a sulfide liquid, covered by an outer shell of silicates. Outgassing during melting and crystallization produced the atmosphere. During differentiation elements would partition into the various layers according to their geochemical character. Goldschmidt distinguished four groups of elements: siderophile elements preferring the metal phase, chalcophile elements preferentially partitioning into sulfide, lithophile elements remaining in the silicate shell, and atmophile elements concentrating into the atmosphere. The geochemical character of each element was derived from its abundance in the corresponding phases of meteorites.At about the same time astronomers began to extract compositional data from absorption line spectroscopy of the solar photosphere, and in a review article, Russell (1941) concluded: "The average composition of meteorites differs from that of the earth's crust significantly, but not very greatly. Iron and magnesium are more abundant and nickel and sulfur rise from subordinate positions to places in the list of the first ten. Silicon, aluminum, and the alkali metals, especially potassium, lose what the others gain." And Russell continued: "The composition of the earth as a whole is probably much more similar to the meteorites than that of its `crust&'." Russell concludes this paragraph by a statement on the composition of the core: "The known properties of the central core are entirely consistent with the assumption that it is composed of molten iron - though not enough to prove it. The generally accepted belief that it is composed of nickel-iron is based on the ubiquitous appearance of this alloy in metallic meteorites," and, we should add, also on the abundances of iron and nickel in the Sun.Despite the vast amount of additional chemical data on terrestrial and meteoritic samples and despite significant improvements in the accuracy of solar abundances, the basic picture as outlined by Russell has not changed. In the following sections we will demonstrate the validity of Russell's assumption and describe some refinements in the estimate of the composition of the Earth and the relationship to meteorites and the Sun.

  20. Toward an improved determination of Earth's lithospheric magnetic field from satellite observations

    NASA Astrophysics Data System (ADS)

    Kotsiaros, S.

    2016-12-01

    An analytical and numerical analysis of the spectral properties of the gradient tensor, initially performed by Rummel and van Gelderen (1992) for the gravity potential, shows that when the tensor elements are grouped into sets of semi-tangential and pure-tangential parts, they produce almost identical signal content as the normal element. Moreover, simple eigenvalue relations can be derived between these sets and the spherical harmonic expansion of the potential. This theoretical development generally applies to any potential field. First, the analysis of Rummel and van Gelderen (1992) is adapted to the magnetic field case and then the elements of the magnetic gradient tensor are estimated by 2 years of Swarm data and grouped into Γ(1) = {[∇B]rθ,[∇B]rφ} resp. Γ(2) = {[∇B]θθ-[∇B]φφ, 2[∇B]θφ}. It is shown that the estimated combinations Γ(1) and Γ(2) produce similar signal content as the theoretical radial gradient [∇B]rr. These results demonstrate the ability of multi-satellite missions such as Swarm, which cannot directly measure the radial gradient, to retrieve similar signal content by means of the horizontal gradients. Finally, lithospheric field models are derived using the gradient combinations Γ(1) and Γ(2) and compared with models derived from traditional vector and gradient data. The model resulting from Γ(1) leads to a very similar, and in particular cases improved, model compared to models retrieved by using approximately three times more data, i.e. a full set of vector, North-South and East-West gradients. ReferencesRummel, R., and M. van Gelderen (1992), Spectral analysis of the full gravity tensor, Geophysical Journal International, 111 (1), 159-169.

  1. Factors affecting trace element content in periurban market garden subsoil in Yunnan Province, China.

    PubMed

    Zu, Yanqun; Bock, Laurent; Schvartz, Christian; Colinet, Gilles; Li, Yuan

    2011-01-01

    Field investigations were conducted to measure subsoil trace element content and factors influencing content in an intensive periurban market garden in Chenggong County, Yunnan Province, South-West China. The area was divided into three different geomorphological units: specifically, mountain (M), transition (T) and lacustrine (L). Mean trace element content in subsoil were determined for Pb (58.2 mg/kg), Cd (0.89 mg/kg), Cu (129.2 mg/kg), and Zn (97.0 mg/kg). Strong significant relationships between trace element content in topsoil and subsoil were observed. Both Pb and Zn were accumulated in topsoil (RTS (ratio of mean trace element in topsoil to subsoil) of Pb and Zn > or =1.0) and Cd and Cu in subsoil (RTS of Cd and Cu < or = 1.0). Subsoil trace element content was related to relief, stoniness, soil color, clay content, and cation exchange capacity. Except for 7.5 YR (yellow-red) color, trace element content increased with color intensity from brown to reddish brown. Significant positive relationships were observed between Fe content and that of Pb and Cu. Trace element content in mountain unit subsoil was higher than in transition and lacustrine units (M > T > L), except for Cu (T > M > L). Mean trace element content in calcareous subsoil was higher than in sandstone and shale. Mean trace element content in clay texture subsoil was higher than in sandy and sandy loam subsoil, and higher Cu and Zn content in subsoil with few mottles. It is possible to model Pb, Cd, Cu, and Zn distribution in subsoil physico-chemical characteristics to help improve agricultural practice.

  2. Geochemistry and origin of metamorphosed mafic rocks from the Lower Paleozoic Moretown and Cram Hill Formations of North-Central Vermont: Delamination magmatism in the western New England appalachians

    USGS Publications Warehouse

    Coish, Raymond; Kim, Jonathan; Twelker, Evan; Zolkos, Scott P.; Walsh, Gregory J.

    2015-01-01

    The Moretown Formation, exposed as a north-trending unit that extends from northern Vermont to Connecticut, is located along a critical Appalachian litho-tectonic zone between the paleomargin of Laurentia and accreted oceanic terranes. Remnants of magmatic activity, in part preserved as metamorphosed mafic rocks in the Moretown Formation and the overlying Cram Hill Formation, are a key to further understanding the tectonic history of the northern Appalachians. Field relationships suggest that the metamorphosed mafic rocks might have formed during and after Taconian deformation, which occurred at ca. 470 to 460 Ma. Geochemistry indicates that the sampled metamorphosed mafic rocks were mostly basalts or basaltic andesites. The rocks have moderate TiO2 contents (1–2.5 wt %), are slightly enriched in the light-rare earth elements relative to the heavy rare earths, and have negative Nb-Ta anomalies in MORB-normalized extended rare earth element diagrams. Their chemistry is similar to compositions of basalts from western Pacific extensional basins near volcanic arcs. The metamorphosed mafic rocks of this study are similar in chemistry to both the pre-Silurian Mount Norris Intrusive Suite of northern Vermont, and also to some of Late Silurian rocks within the Lake Memphremagog Intrusive Suite, particularly the Comerford Intrusive Complex of Vermont and New Hampshire. Both suites may be represented among the samples of this study. The geochemistry of all samples indicates that parental magmas were generated in supra-subduction extensional environments during lithospheric delamination.

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

    PubMed

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

    2017-01-01

    Studies have shown that residents living near rare earth mining areas have high concentrations of rare earth elements (REEs) in their hair. However, the adverse effects of REEs on human health have rarely been the focus of epidemiological studies. The goal of this study was to evaluate the relationship between REEs in hair and the risk of hypertension in housewives. We recruited 398 housewives in Shanxi Province, China, consisting of 163 women with hypertension (cases) and 235 healthy women without hypertension (controls). We analyzed 15 REEs (lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), Yttrium (Y), cerium (Ce), praseodymium (Pr), and neodymium (Nd)) and calcium (Ca) accumulated in housewives hair over a period of two years. The results revealed that, with the exception of Eu, concentrations of the REEs in hair were higher in the cases than in the controls. The univariate odds ratios (ORs) of the 14 REEs were >1, and four of the REEs (Dy, Tm, Yb, and Y) also had adjusted ORs > 1. The increasing dose-response trends of the four REEs further indicated the potential for increased hypertension risk. Moreover, the REEs were negatively correlated with Ca content in hair. These results might suggest an antagonistic effect of REEs on Ca in the human body. It was concluded that high intake of REEs might increase the risk of hypertension among housewives. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Application of New Partition Coefficients to Modeling Plagioclase

    NASA Technical Reports Server (NTRS)

    Fagan, A. L.; Neal, C. R.; Rapp, J. F.; Draper, D. S.; Lapen, T. J.

    2017-01-01

    Previously, studies that determined the partition coefficient for an element, i, between plagioclase and the residual basaltic melt (Di plag) have been conducted using experimental conditions dissimilar from the Moon, and thus these values are not ideal for modeling plagioclase fractionation in a lunar system. However, recent work [1] has determined partition coefficients for plagioclase at lunar oxygen fugacities, and resulted in plagioclase with Anorthite contents =An90; these are significantly more calcic than plagioclase in previous studies, and the An content has a profound effect on partition coefficient values [2,3]. Plagioclase D-values, which are dependent on the An content of the crystal [e.g., 2-6], can be determined using published experimental data and the correlative An contents. Here, we examine new experimental data from [1] to ascertain their effect on the calculation of equilibrium liquids from Apollo 16 sample 60635,2. This sample is a coarse grained, subophitic impact melt composed of 55% plagioclase laths with An94.4-98.7 [7,8], distinctly more calcic than of previous partition coefficient studies (e.g., [3-6, 9-10]). Sample 60635,2 is notable as having several plagioclase trace element analyses containing a negative Europium anomaly (-Eu) in the rare-earth element (REE) profile, rather than the typical positive Eu anomaly (+Eu) [7-8] (Fig. 1). The expected +Eu is due to the similarity in size and charge with Ca2+, thereby allowing Eu2+ to be easily taken up by the plagioclase crystal structure, in contrast to the remaining REE3+. Some 60635,2 plagioclase crystals only have +Eu REE profiles, some only have -Eu REE profiles, and some +Eu and -Eu analyses in different areas on a single crystal [7, 8]. Moreover, there does not seem to be any core-rim association with the +Eu or -Eu analyses, nor does there appear to be a correlation between the size, shape, or location of a particular crystal within the sample and the sign of its Eu anomaly, which suggests a complex evolution. In order to investigate this sample further, we can calculate the equilibrium liquids, but with An contents distinct from previous experimental studies, we must calculate the appropriate partition coefficients for each trace element analysis.

  5. Rare earths recovery and gypsum upgrade from Florida phosphogypsum

    DOE PAGES

    Liang, Haijun; Zhang, Patrick; Jin, Zhen; ...

    2017-11-01

    Phosphogypsum is a byproduct created during the production of industrial wet-process phosphoric acid. This study focused on recovering rare earth elements (REEs) from a Florida phosphogypsum sample and investigated the effects of removing detrimental impurities such as phosphorus pentoxide (P 2O 5), uranium (U) and fluorine (F) during the leaching process. Experimental results indicated that REE leaching efficiency increased rapidly, reached a maximum and then began to decrease with sulfuric acid concentrations ranging from 0 to 10 percent and temperatures ranging from 20 to 70 °C. At a sulfuric acid concentration of 5 percent and leaching temperature of 50 °C,more » REE leaching efficiency obtained a maximum value of approximately 43 percent. Increasing the leaching time or liquid/solid ratio increased the leaching efficiency. The leaching efficiencies of P 2O 5, U and F consistently increased with sulfuric acid concentration, temperature, leaching time and liquid/solid ratio within the testing ranges. A fine-grain gypsum concentrate, sized smaller than 40 μm, was separated from leached phosphogypsum through elutriation, in which the P 2O 5, U and F content levels were reduced by 99, 70 and 83 percent, respectively, from their content levels in fresh phosphogypsum.« less

  6. Nanostructured crystals of fluorite phases Sr1 - x R x F2 + x ( R = Y, La-Lu) and their ordering: Part III. A study of the refractive indices

    NASA Astrophysics Data System (ADS)

    Glushkova, T. M.; Karimov, D. N.; Krivandina, E. A.; Zhmurova, Z. I.; Sobolev, B. P.

    2009-07-01

    The refractive indices n of Sr1 - x R x F2 + x crystals ( R = Y, La-Lu; 0 ≤ x ≤ 0.5) have been measured at wavelengths of 0.436, 0.546, and 0.589 μm. It is established that n increases when there is an increase in the RF3 content x according to a weakly quadratic law for each R. For the isoconcentration series of Sr0.9 R 0.1F2.1 crystals, the change in n in the series of rare earth elements has a pronounced nonlinear character, which reflects the nonmonotonous change in the properties of compounds in the R series. It is shown that the method of molecular refraction additivity can be used to calculate n for Sr1 - x R x F2 + x crystals. By varying the RF3 content in them, one can obtain optical media with a gradually varied refractive index n in the range 1.44-1.55, thus filling the gap in the n values between high ones for RF3 crystals and low ones for crystals of alkaline earth fluorides MF2.

  7. Rare earths recovery and gypsum upgrade from Florida phosphogypsum

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Liang, Haijun; Zhang, Patrick; Jin, Zhen

    Phosphogypsum is a byproduct created during the production of industrial wet-process phosphoric acid. This study focused on recovering rare earth elements (REEs) from a Florida phosphogypsum sample and investigated the effects of removing detrimental impurities such as phosphorus pentoxide (P 2O 5), uranium (U) and fluorine (F) during the leaching process. Experimental results indicated that REE leaching efficiency increased rapidly, reached a maximum and then began to decrease with sulfuric acid concentrations ranging from 0 to 10 percent and temperatures ranging from 20 to 70 °C. At a sulfuric acid concentration of 5 percent and leaching temperature of 50 °C,more » REE leaching efficiency obtained a maximum value of approximately 43 percent. Increasing the leaching time or liquid/solid ratio increased the leaching efficiency. The leaching efficiencies of P 2O 5, U and F consistently increased with sulfuric acid concentration, temperature, leaching time and liquid/solid ratio within the testing ranges. A fine-grain gypsum concentrate, sized smaller than 40 μm, was separated from leached phosphogypsum through elutriation, in which the P 2O 5, U and F content levels were reduced by 99, 70 and 83 percent, respectively, from their content levels in fresh phosphogypsum.« less

  8. Origin of Volatiles in Earth: Indigenous Versus Exogenous Sources Based on Highly Siderophile, Volatile Siderophile, and Light Volatile Elements

    NASA Technical Reports Server (NTRS)

    Righter, K.; Danielson, L.; Pando, K. M.; Marin, N.; Nickodem, K.

    2015-01-01

    Origin of Earth's volatiles has traditionally been ascribed to late accretion of material after major differentiation events - chondrites, comets, ice or other exogenous sources. A competing theory is that the Earth accreted its volatiles as it was built, thus water and other building blocks were present early and during differentiation and core formation (indigenous). Here we discuss geochemical evidence from three groups of elements that suggests Earth's volatiles were acquired during accretion and did not require additional sources after differentiation.

  9. Superconducting structure

    DOEpatents

    Kwon, Chuhee; Jia, Quanxi; Foltyn, Stephen R.

    2003-04-01

    A superconductive structure including a dielectric oxide substrate, a thin buffer layer of a superconducting material thereon; and, a layer of a rare earth-barium-copper oxide superconducting film thereon the thin layer of yttrium-barium-copper oxide, the rare earth selected from the group consisting of samarium, gadolinium, ytterbium, erbium, neodymium, dysprosium, holmium, lutetium, a combination of more than one element from the rare earth group and a combination of one or more elements from the rare earth group with yttrium, the buffer layer of superconducting material characterized as having chemical and structural compatibility with the dielectric oxide substrate and the rare earth-barium-copper oxide superconducting film is provided.

  10. Superconducting Structure

    DOEpatents

    Kwon, Chuhee; Jia, Quanxi; Foltyn, Stephen R.

    2005-09-13

    A superconductive structure including a dielectric oxide substrate, a thin buffer layer of a superconducting material thereon; and, a layer of a rare earth-barium-copper oxide superconducting film thereon the thin layer of yttrium-barium-copper oxide, the rare earth selected from the group consisting of samarium, gadolinium, ytterbium, erbium, neodymium, dysprosium, holmium, lutetium, a combination of more than one element from the rare earth group and a combination of one or more elements from the rare earth group with yttrium, the buffer layer of superconducting material characterized as having chemical and structural compatibility with the dielectric oxide substrate and the rare earth-barium-copper oxide superconducting film is provided.

  11. Evidence against a chondritic Earth.

    PubMed

    Campbell, Ian H; O'Neill, Hugh St C

    2012-03-28

    The (142)Nd/(144)Nd ratio of the Earth is greater than the solar ratio as inferred from chondritic meteorites, which challenges a fundamental assumption of modern geochemistry--that the composition of the silicate Earth is 'chondritic', meaning that it has refractory element ratios identical to those found in chondrites. The popular explanation for this and other paradoxes of mantle geochemistry, a hidden layer deep in the mantle enriched in incompatible elements, is inconsistent with the heat flux carried by mantle plumes. Either the matter from which the Earth formed was not chondritic, or the Earth has lost matter by collisional erosion in the later stages of planet formation.

  12. A LOW-COST RARE EARTH ELEMENTS RECOVERY TECHNOLOGY - PHASE I

    EPA Science Inventory

    Physical Sciences, Inc., and the University of Kentucky Center for Applied Energy Research propose to develop a unique enabling technology to significantly reduce U.S. dependency for Rare Earth Elements (REE) on foreign suppliers and our global competitors. Our innovation...

  13. Rare Earth Element Concentrations in Submarine Hydrothermal Fluids

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fowler, Andrew; Zierenberg, Robert

    Rare earth element concentrations in submarine hydrothermal fluids from Alarcon Rise, East Pacific Rise, REE concentrations in submarine hydrothermal fluids from Pescadero Basin, Gulf of California, and the Cleft vent field, southern Juan de Fuca Ridge. Data are not corrected to zero Mg.

  14. [Content of mineral elements of Gastrodia elata by principal components analysis].

    PubMed

    Li, Jin-ling; Zhao, Zhi; Liu, Hong-chang; Luo, Chun-li; Huang, Ming-jin; Luo, Fu-lai; Wang, Hua-lei

    2015-03-01

    To study the content of mineral elements and the principal components in Gastrodia elata. Mineral elements were determined by ICP and the data was analyzed by SPSS. K element has the highest content-and the average content was 15.31 g x kg(-1). The average content of N element was 8.99 g x kg(-1), followed by K element. The coefficient of variation of K and N was small, but the Mn was the biggest with 51.39%. The highly significant positive correlation was found among N, P and K . Three principal components were selected by principal components analysis to evaluate the quality of G. elata. P, B, N, K, Cu, Mn, Fe and Mg were the characteristic elements of G. elata. The content of K and N elements was higher and relatively stable. The variation of Mn content was biggest. The quality of G. elata in Guizhou and Yunnan was better from the perspective of mineral elements.

  15. Combined Effects of Lanthanum (III) and Acid Rain on Antioxidant Enzyme System in Soybean Roots.

    PubMed

    Zhang, Xuanbo; Du, Yuping; Wang, Lihong; Zhou, Qing; Huang, Xiaohua; Sun, Zhaoguo

    2015-01-01

    Rare earth element pollution (REEs) and acid rain (AR) pollution simultaneously occur in many regions, which resulted in a new environmental issue, the combined pollution of REEs and AR. The effects of the combined pollution on the antioxidant enzyme system of plant roots have not been reported. Here, the combined effects of lanthanum ion (La3+), one type of REE, and AR on the antioxidant enzyme system of soybean roots were investigated. In the combined treatment of La3+ (0.08 mM) and AR, the cell membrane permeability and the peroxidation of cell membrane lipid of soybean roots increased, and the superoxide dismutase, catalase, peroxidase and reduced ascorbic acid served as scavengers of reactive oxygen species. In other combined treatments of La3+ (0.40 mM, 1.20 mM) and AR, the membrane permeability, malonyldialdehyde content, superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content increased, while the catalase activity decreased. The increased superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content were inadequate to scavenge the excess hydrogen peroxide and superoxide, leading to the damage of the cell membrane, which was aggravated with the increase in the concentration of La3+ and the level of AR. The deleterious effects of the combined treatment of La3+ and AR were stronger than those of the single treatment of La3+ or AR. Moreover, the activity of antioxidant enzyme system in the combined treatment group was affected directly and indirectly by mineral element content in soybean plants.

  16. Combined Effects of Lanthanum (III) and Acid Rain on Antioxidant Enzyme System in Soybean Roots

    PubMed Central

    Zhang, Xuanbo; Du, Yuping; Wang, Lihong; Zhou, Qing; Huang, Xiaohua; Sun, Zhaoguo

    2015-01-01

    Rare earth element pollution (REEs) and acid rain (AR) pollution simultaneously occur in many regions, which resulted in a new environmental issue, the combined pollution of REEs and AR. The effects of the combined pollution on the antioxidant enzyme system of plant roots have not been reported. Here, the combined effects of lanthanum ion (La3+), one type of REE, and AR on the antioxidant enzyme system of soybean roots were investigated. In the combined treatment of La3+ (0.08 mM) and AR, the cell membrane permeability and the peroxidation of cell membrane lipid of soybean roots increased, and the superoxide dismutase, catalase, peroxidase and reduced ascorbic acid served as scavengers of reactive oxygen species. In other combined treatments of La3+ (0.40 mM, 1.20 mM) and AR, the membrane permeability, malonyldialdehyde content, superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content increased, while the catalase activity decreased. The increased superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content were inadequate to scavenge the excess hydrogen peroxide and superoxide, leading to the damage of the cell membrane, which was aggravated with the increase in the concentration of La3+ and the level of AR. The deleterious effects of the combined treatment of La3+ and AR were stronger than those of the single treatment of La3+ or AR. Moreover, the activity of antioxidant enzyme system in the combined treatment group was affected directly and indirectly by mineral element content in soybean plants. PMID:26230263

  17. Petrogenesis of coeval sodic and potassic alkaline magmas at Spanish Peaks, Colorado: Magmatism related to the opening of the Rio Grande rift

    NASA Astrophysics Data System (ADS)

    Lord, A. Brooke Hamil; McGregor, Heath; Roden, Michael F.; Salters, Vincent J. M.; Sarafian, Adam; Leahy, Rory

    2016-07-01

    Approximately coeval, relatively primitive (∼5-10% MgO with exception of a trachyandesite) alkaline mafic dikes and sills at or near Spanish Peaks, CO are divided into relatively sodic and potassic varieties on the basis of K2O/Na2O. Many of these dikes are true lamprophyres. In spite of variable alkali element ratios, the alkaline rocks share a number of geochemical similarities: high LIL element contents, high Ba and similar Sr, Nd and Hf isotope ratios near that of Bulk Earth. One important difference is that the potassic rocks are characterized by lower Al2O3 contents, typically less than 12 wt.%, than the sodic dikes/sills which typically have more than 13 wt.% Al2O3, and this difference is independent of MgO content. We attribute the distinct Al2O3 contents to varying pressure during melting: a mica-bearing, Al-poor vein assemblage for the potassic magmas melted at higher pressure than an aluminous amphibole-bearing vein assemblage for the sodic magmas. Remarkable isotopic and trace element similarities with approximately contemporaneous, nearby Rio Grande rift-related basalts in the San Luis Valley, indicate that the magmatism at Spanish Peaks was rift-related, and that lithosphere sources were shared between some rift magmas and those at Spanish Peaks. High Zn/Fe ratios in the Spanish Peaks mafic rocks point to a clinopyroxene- and garnet-rich source such as lithosphere veined by pyroxenite or eclogite. Lithospheric melting was possibly triggered by foundering of cool, dense lithosphere beneath the Rio Grande rift during the initiation of rifting with the potassic parent magmas generated by higher pressure melting of the foundered lithosphere than the sodic parent magmas. This process, caused by gravitational instability of the lithosphere (Elkins-Tanton, 2007) may be common beneath active continental rifts.

  18. Nanominerals and potentially hazardous elements from coal cleaning rejects of abandoned mines: Environmental impact and risk assessment.

    PubMed

    Fdez-Ortiz de Vallejuelo, Silvia; Gredilla, Ainara; da Boit, Kátia; Teixeira, Elba C; Sampaio, Carlos H; Madariaga, Juan Manuel; Silva, Luis F O

    2017-02-01

    Soils around coal mining are important reservoir of hazardous elements (HEs), nanominerals, and ultrafine compounds. This research reports and discusses the soil concentrations of HEs (As, Cd, Cr, Cu, Ni, Pb, and Zn) in coal residues of abandoned mines. To assess differences regarding environmental impact and risk assessment between coal abandoned mines from the Santa Catarina state, eighteen coal cleaning rejects with different mineralogical and chemical composition, from eight abandoned mines were collected. Nanominerals and ultra-fine minerals from mining-contaminated areas were analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscope (HR-TEM), providing new information on the mineralogy and nano-mineralogy of these coal residues. The total contents of 57 elements (HEs, alkali metals, and rare earth elements) were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The calculation of NWACs (Normalized Average Weighted Concentration), together with the chemometric analysis by Principal component analysis (PCA) confirmed the variability of the samples regarding their city and their mine of origin. Moreover, the results confirmed the existence of hotspots in mines near urban areas. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Basin Excavation, Lower Crust, Composition, and Bulk Moon Mass balance in Light of a Thin Crust

    NASA Technical Reports Server (NTRS)

    Jolliff, B. L.; Korotev, R. L.; Ziegler, R. A.

    2013-01-01

    New lunar gravity results from GRAIL have been interpreted to reflect an overall thin and low-density lunar crust. Accordingly, crustal thickness has been modeled as ranging from 0 to 60 km, with thinnest crust at the locations of Crisium and Moscoviense basins and thickest crust in the central farside highlands. The thin crust has cosmochemical significance, namely in terms of implications for the Moon s bulk composition, especially refractory lithophile elements that are strongly concentrated in the crust. Wieczorek et al. concluded that the bulk Moon need not be enriched compared to Earth in refractory lithophile elements such as Al. Less Al in the crust means less Al has been extracted from the mantle, permitting relatively low bulk lunar mantle Al contents and low pre- and post-crust-extraction values for the mantle (or the upper mantle if only the upper mantle underwent LMO melting). Simple mass-balance calculations using the method of [4] suggests that the same conclusion might hold for Th and the entire suite of refractory lithophile elements that are incompatible in olivine and pyroxene, including the KREEP elements, that are likewise concentrated in the crust.

  20. Selected Trace Element Concentrations in Peat Used for Cosmetic Production - A Case Study from Southern Poland

    NASA Astrophysics Data System (ADS)

    Glina, Bartłomiej

    2016-12-01

    The aim of the study was to assess the concentration of selected trace elements in organic soils used as a source to obtain a unique peat extract for cosmetics production. Peat material for laboratory analysis were collected from fen peatland located in the Prosna River Valley (Borek village). Studied peatland is managed by "Torf Corporation" company as a source of material to obtain peat extract for cosmetics production. In the collected soil samples (four soil profiles) Zn, Cu and Pb concentrations were determined by using atomic absorption spectrometer SpectraAA 220 (Varian), after acid digestion. Obtained results showed that the highest concentrations of selected trace elements were recorded in the surface horizons of organic soils. This fact might be the results of Prosna river flooding or air deposition. Howevere, according to the new Polish regulations (Ordinance of the Minister for Environment 01.09.2016 - the way of conducting contamination assessment of the earth surface), the content of trace elements in the examined soils was greatly belowe the permissible limit for areas from group IV (mine lands). Thus, described soils are proper to obtain peat extract used as a component in cosmetic production.

  1. Research Issues in Image Registration for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Eastman, Roger D.; LeMoigne, Jacqueline; Netanyahu, Nathan S.

    2007-01-01

    Image registration is an important element in data processing for remote sensing with many applications and a wide range of solutions. Despite considerable investigation the field has not settled on a definitive solution for most applications and a number of questions remain open. This article looks at selected research issues by surveying the experience of operational satellite teams, application-specific requirements for Earth science, and our experiments in the evaluation of image registration algorithms with emphasis on the comparison of algorithms for subpixel accuracy. We conclude that remote sensing applications put particular demands on image registration algorithms to take into account domain-specific knowledge of geometric transformations and image content.

  2. Earth Science Content Guidelines Grades K-12.

    ERIC Educational Resources Information Center

    American Geological Inst., Alexandria, VA.

    Teams of teachers, other science educators, and scientists selected from a national search for project writers have proposed using the following set of questions to guide the inclusion of earth science content into the kindergarten through grade 12 curriculum. The Essential Questions are organized in a K-12 sequence by six content areas: (1) Solid…

  3. Method of treating waste water

    DOEpatents

    Deininger, J. Paul; Chatfield, Linda K.

    1991-01-01

    A process of treating water to remove transuranic elements contained therein by adjusting the pH of a transuranic element-containing water source to within the range of about 6.5 to about 14.0, admixing the water source with an alkali or alkaline earth ferrate in an amount sufficient to form a precipitate within the water source, the amount of ferrate effective to reduce the transuranic element concentration in the water source, permitting the precipitate in the admixture to separate and thereby yield a supernatant liquid having a reduced transuranic element concentration, and separating the supernatant liquid having the reduced transuranic element concentration from the admixture is provided. Additionally, a water soluble salt, e.g., a zirconium salt, can be added with the alkali or alkaline earth ferrate in the process to provide greater removal efficiencies. A composition of matter including an alkali or alkaline earth ferrate and a water soluble salt, e.g., a zirconium salt, is also provided.

  4. Demandite, lunar materials and space industrialization

    NASA Technical Reports Server (NTRS)

    Criswell, D. R.

    1977-01-01

    Terrestrial industry consumes a wide range of elements in producing the outputs which support and make industrial societies possible. 'Demandite' is a conceptual or synthetic molecule which is composed of the weight fractions of the major elements consumed by industry. Demandite needed for mature industrial activities in space will differ from the terrestrial composition because solar energy must replace hydrocarbon-energy, lunar and asteroidal bulk compositions are different from mineral deposits on the earth, and the major bulk processing in space will be the creation of radiation shielding for human habitats to provide real estate in space complete with water, atmosphere and life-stock elements. Demandite cost may be dominated by earth to deep space transport cost of minor elemental constituents depleted in the lunar soils unless careful attention is given to substitution of materials, searches of the moon (polar regions) and asteroids for the depleted elements, and continuing lowering of earth to deep space transport costs.

  5. Timing of pyroxenite formation in supra-subduction Josephine Ophiolite, Oregon.

    NASA Astrophysics Data System (ADS)

    Hough, T.; Le Roux, V.; Kurz, M. D.

    2017-12-01

    The Josephine ophiolite is a partly dismembered ophiolite located in southern Oregon and northwestern California (USA). It displays a large ( 640 km2) mantle section that is mostly composed of depleted spinel harzburgite and lherzolite re-equilibrated at temperatures of 900 °C. In addition, the peridotite section of the ophiolite contains minor dunites and pyroxenite veins ranging from orthopyroxenites to clinopyroxenites. Using field, petrological and geochemical data, previous studies have shown that the peridotite experienced 10-20% of hydrous flux melting. In addition, clinopyroxene and orthopyroxene in harzburgites show variable degrees of light rare-earth element (LREE) enrichment, which suggests percolation and re-equilibration with small fractions of boninite melt. Overall, the trace element concentrations of pyroxenes indicate that the harzburgites experienced particularly high degrees of melting in the mantle wedge. We collected a number of orthopyroxenite and clinopyroxenite veins in the mantle section of the Josephine Ophiolite. Here we present the major and rare-earth element (REE) contents of pyroxene in 4 orthopyroxenites and 2 clinopyroxenites and calculate the major element and REE closure temperatures for individual veins. We show that individual pyroxenites record drastic variations in their degree of REE depletion, indicating that multiple generations of melts percolated the peridotite. The pyroxenite veins also record higher REE closure temperatures (>1200 ºC) compared to the surrounding peridotite, potentially indicating rapid cooling after emplacement. REE closure temperatures are also higher than major element closure temperatures. In parallel, we analyzed Sr isotopes by MC-ICPMS in pyroxene separates from 4 veins. Results indicate that the maximum age of emplacement of orthopyroxenite veins corresponds to the age of exhumation. Some clinopyroxenites may have formed during earlier melt percolation events. This study supports the idea that the composition of melts that percolate the mantle wedge can be highly variable and that orthopyroxenites may be the last type of veins to form in those environments.

  6. HISTORY OF THE ORIGIN OF THE CHEMICAL ELEMENTS AND THEIR DISCOVERIES.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    HOLDEN,N.E.

    The origin of the chemical elements show a wide diversity with some of these elements having their origin in antiquity. Still other elements have been synthesized within the past fifty years via nuclear reactions on heavy elements, because these other elements are unstable and radioactive and do not exist in nature. The names of the elements come from many sources including mythological concepts or characters; places, areas or countries; properties of the element or its compounds, such as color, smell or its inability to combine; and the names of scientists. There are also some miscellaneous names as well as somemore » obscure names for particular elements. The claim of discovery of an element has varied over the centuries. Many claims, e.g., the discovery of certain rare earth elements of the lanthanide series, involved the discovery of a mineral ore from which an element was later extracted. The honor of discovery has often been accorded not to the person who first isolated the element but to the person who discovered the original mineral itself, even when the ore was impure and contained many elements. The reason for this is that in the case of these rare earth elements, the ''earth'' now refers to oxides of a metal not to the metal itself. This fact was not realized at the time of their discovery, until the English chemist Humphry Davy showed that earths were compounds of oxygen and metals in 1808. In the early discoveries, the atomic weight of an element and spectral analysis of the element were not available. Later both of these elemental properties would be required before discovery of the element would be accepted. In general, the requirements for discovery claims have tightened through the years and claims that were previously accepted would no longer meet the minimum constraints now imposed. There are cases where the honor of discovery is not given to the first person to actually discover the element but to the first person to claim the discovery in print. If a publication was delayed, the discoverer has often historically been ''scooped'' by another scientist.« less

  7. Geochemical Constraints on Core Formation in the Earth

    NASA Technical Reports Server (NTRS)

    Jones, John H.; Drake, Michael J.

    1986-01-01

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

  8. Rare Earth Oxide Fluoride Nanoparticles And Hydrothermal Method For Forming Nanoparticles

    DOEpatents

    Fulton, John L.; Hoffmann, Markus M.

    2003-12-23

    A hydrothermal method for forming nanoparticles of a rare earth element, oxygen and fluorine has been discovered. Nanoparticles comprising a rare earth element, oxygen and fluorine are also described. These nanoparticles can exhibit excellent refractory properties as well as remarkable stability in hydrothermal conditions. The nanoparticles can exhibit excellent properties for numerous applications including fiber reinforcement of ceramic composites, catalyst supports, and corrosion resistant coatings for high-temperature aqueous solutions.

  9. Rare earth oxide fluoride nanoparticles and hydrothermal method for forming nanoparticles

    DOEpatents

    Fulton, John L [Richland, WA; Hoffmann, Markus M [Richland, WA

    2001-11-13

    A hydrothermal method for forming nanoparticles of a rare earth element, oxygen and fluorine has been discovered. Nanoparticles comprising a rare earth element, oxygen and fluorine are also described. These nanoparticles can exhibit excellent refractory properties as well as remarkable stability in hydrothermal conditions. The nanoparticles can exhibit excellent properties for numerous applications including fiber reinforcement of ceramic composites, catalyst supports, and corrosion resistant coatings for high-temperature aqueous solutions.

  10. Conditions of Core Formation in the Early Earth: Single Stage or Heterogeneous Accretion?

    NASA Technical Reports Server (NTRS)

    Righter, Kevin

    2010-01-01

    Since approx.1990 high pressure and temperature (PT) experiments on metal-silicate systems have showed that partition coefficients [D(met/sil)] for siderophile (iron-loving) elements are much different than those measured at low PT conditions [1,2]. The high PT data have been used to argue for a magma ocean during growth of the early Earth [3,4]. In the ensuing decades there have been hundreds of new experiments carried out and published on a wide range of siderophile elements (> 80 experiments published for Ni, Co, Mo, W, P, Mn, V, Cr, Ga, Cu and Pd). At the same time several different models have been advanced to explain the siderophile elements in Earth's mantle: a) shallow depth magma ocean 25-30 GPa [3,5]; b) deep magma ocean; up to 50 GPa [6,7], and c) early reduced and later oxidized magma ocean [8,9]. Some studies have drawn conclusions based on a small subset of siderophile elements, or a set of elements that provides little leverage on the big picture (like slightly siderophile elements), and no single study has attempted to quantitatively explain more than 5 elements at a time. The purpose of this abstract is to identify issues that have lead to a difference in interpretation, and to present updated predictive expressions based on new experimental data. The resulting expressions will be applied to the siderophile element depletions in Earth's upper mantle.

  11. Seismic sources

    DOEpatents

    Green, M.A.; Cook, N.G.W.; McEvilly, T.V.; Majer, E.L.; Witherspoon, P.A.

    1987-04-20

    Apparatus is described for placement in a borehole in the earth, which enables the generation of closely controlled seismic waves from the borehole. Pure torsional shear waves are generated by an apparatus which includes a stator element fixed to the borehole walls and a rotor element which is electrically driven to rapidly oscillate on the stator element to cause reaction forces transmitted through the borehole walls to the surrounding earth. Longitudinal shear waves are generated by an armature that is driven to rapidly oscillate along the axis of the borehole, to cause reaction forces transmitted to the surrounding earth. Pressure waves are generated by electrically driving pistons that press against opposite ends of a hydraulic reservoir that fills the borehole. High power is generated by energizing the elements for more than about one minute. 9 figs.

  12. Analysis of Rare Earth Elements in Uranium Using Handheld Laser-Induced Breakdown Spectroscopy (HH LIBS)

    DOE PAGES

    Manard, Benjamin T.; Wylie, E. Miller; Willson, Stephen P.

    2018-05-22

    In this paper, a portable handheld laser-induced breakdown spectroscopy (HH LIBS) instrument was evaluated as a rapid method to qualitatively analyze rare earth elements in a uranium oxide matrix. This research is motivated by the need for development of a method to perform rapid, at-line chemical analysis in a nuclear facility, particularly to provide a rapid first pass analysis to determine if additional actions or measurements are warranted. This will result in the minimization of handling and transport of radiological and nuclear material and subsequent exposure to their associated hazards. In this work, rare earth elements (Eu, Nd, and Yb)more » were quantitatively spiked into a uranium oxide powder and analyzed by the HH LIBS instrumentation. This method demonstrates the ability to rapidly identify elemental constituents in sub-percent levels in a uranium matrix. Preliminary limits of detection (LODs) were determined with values on the order of hundredths of a percent. Validity of this methodology was explored by employing a National Institute of Standards and Technology (NIST) standard reference materials (SRM) 610 and 612 (Trace Elements in Glass). Finally, it was determined that the HH LIBS method was able to clearly discern the rare earths elements of interest in the glass or uranium matrices.« less

  13. Analysis of Rare Earth Elements in Uranium Using Handheld Laser-Induced Breakdown Spectroscopy (HH LIBS)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Manard, Benjamin T.; Wylie, E. Miller; Willson, Stephen P.

    In this paper, a portable handheld laser-induced breakdown spectroscopy (HH LIBS) instrument was evaluated as a rapid method to qualitatively analyze rare earth elements in a uranium oxide matrix. This research is motivated by the need for development of a method to perform rapid, at-line chemical analysis in a nuclear facility, particularly to provide a rapid first pass analysis to determine if additional actions or measurements are warranted. This will result in the minimization of handling and transport of radiological and nuclear material and subsequent exposure to their associated hazards. In this work, rare earth elements (Eu, Nd, and Yb)more » were quantitatively spiked into a uranium oxide powder and analyzed by the HH LIBS instrumentation. This method demonstrates the ability to rapidly identify elemental constituents in sub-percent levels in a uranium matrix. Preliminary limits of detection (LODs) were determined with values on the order of hundredths of a percent. Validity of this methodology was explored by employing a National Institute of Standards and Technology (NIST) standard reference materials (SRM) 610 and 612 (Trace Elements in Glass). Finally, it was determined that the HH LIBS method was able to clearly discern the rare earths elements of interest in the glass or uranium matrices.« less

  14. Analysis of Rare Earth Elements in Uranium Using Handheld Laser-Induced Breakdown Spectroscopy (HH LIBS).

    PubMed

    Manard, Benjamin T; Wylie, E Miller; Willson, Stephen P

    2018-01-01

    A portable handheld laser-induced breakdown spectroscopy (HH LIBS) instrument was evaluated as a rapid method to qualitatively analyze rare earth elements in a uranium oxide matrix. This research is motivated by the need for development of a method to perform rapid, at-line chemical analysis in a nuclear facility, particularly to provide a rapid first pass analysis to determine if additional actions or measurements are warranted. This will result in the minimization of handling and transport of radiological and nuclear material and subsequent exposure to their associated hazards. In this work, rare earth elements (Eu, Nd, and Yb) were quantitatively spiked into a uranium oxide powder and analyzed by the HH LIBS instrumentation. This method demonstrates the ability to rapidly identify elemental constituents in sub-percent levels in a uranium matrix. Preliminary limits of detection (LODs) were determined with values on the order of hundredths of a percent. Validity of this methodology was explored by employing a National Institute of Standards and Technology (NIST) standard reference materials (SRM) 610 and 612 (Trace Elements in Glass). It was determined that the HH LIBS method was able to clearly discern the rare earths elements of interest in the glass or uranium matrices.

  15. A nucleosynthetic origin for the Earth’s anomalous 142Nd composition

    DOE PAGES

    Burkhardt, C.; Borg, L. E.; Brennecka, G. A.; ...

    2016-09-14

    A long-standing paradigm assumes that the chemical and isotopic compositions of many elements in the bulk silicate Earth are the same as in chondrites(1-4). But, the accessible Earth has a greater Nd-142/Nd-144 ratio than do chondrites. Because Nd-142 is the decay product of the now-extinct Sm-146 (which has a half-life of 103 million years(5)), this Nd-142 difference seems to require a higher-than-chondritic Sm/Nd ratio for the accessible Earth. This must have been acquired during global silicate differentiation within the first 30 million years of Solar System formation(6) and implies the formation of a complementary Nd-142-depleted reservoir that either is hiddenmore » in the deep Earth(6), or lost to space by impact erosion(3,7). Whether this complementary reservoir existed, and whether or not it has been lost from Earth, is a matter of debate(3,8,9), and has implications for determining the bulk composition of Earth, its heat content and structure, as well as for constraining the modes and timescales of its geodynamical evolution(3,7,9,10). We show that, compared with chondrites, Earth's precursor bodies were enriched in neodymium that was produced by the slow neutron capture process (s-process) of nucleosynthesis. This s-process excess leads to higher Nd-142/Nd-144 ratios; after correction for this effect, the Nd-142/Nd-144 ratios of chondrites and the accessible Earth are indistinguishable within five parts per million. The Nd-142 offset between the accessible silicate Earth and chondrites therefore reflects a higher proportion of s-process neodymium in the Earth, and not early differentiation processes. Our results obviate the need for hidden-reservoir or super-chondritic Earth models and imply a chondritic Sm/Nd ratio for the bulk Earth. Although chondrites formed at greater heliocentric distances and contain a different mix of presolar components than Earth, they nevertheless are suitable proxies for Earth's bulk chemical composition.« less

  16. A nucleosynthetic origin for the Earth’s anomalous 142Nd composition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Burkhardt, C.; Borg, L. E.; Brennecka, G. A.

    A long-standing paradigm assumes that the chemical and isotopic compositions of many elements in the bulk silicate Earth are the same as in chondrites(1-4). But, the accessible Earth has a greater Nd-142/Nd-144 ratio than do chondrites. Because Nd-142 is the decay product of the now-extinct Sm-146 (which has a half-life of 103 million years(5)), this Nd-142 difference seems to require a higher-than-chondritic Sm/Nd ratio for the accessible Earth. This must have been acquired during global silicate differentiation within the first 30 million years of Solar System formation(6) and implies the formation of a complementary Nd-142-depleted reservoir that either is hiddenmore » in the deep Earth(6), or lost to space by impact erosion(3,7). Whether this complementary reservoir existed, and whether or not it has been lost from Earth, is a matter of debate(3,8,9), and has implications for determining the bulk composition of Earth, its heat content and structure, as well as for constraining the modes and timescales of its geodynamical evolution(3,7,9,10). We show that, compared with chondrites, Earth's precursor bodies were enriched in neodymium that was produced by the slow neutron capture process (s-process) of nucleosynthesis. This s-process excess leads to higher Nd-142/Nd-144 ratios; after correction for this effect, the Nd-142/Nd-144 ratios of chondrites and the accessible Earth are indistinguishable within five parts per million. The Nd-142 offset between the accessible silicate Earth and chondrites therefore reflects a higher proportion of s-process neodymium in the Earth, and not early differentiation processes. Our results obviate the need for hidden-reservoir or super-chondritic Earth models and imply a chondritic Sm/Nd ratio for the bulk Earth. Although chondrites formed at greater heliocentric distances and contain a different mix of presolar components than Earth, they nevertheless are suitable proxies for Earth's bulk chemical composition.« less

  17. Highly alkaline lavas in a Proterozoic rift zone: Implications for Precambrian mantle metasomatic processes

    NASA Astrophysics Data System (ADS)

    Gaonac'h, H.; Ludden, J. N.; Picard, C.; Francis, D.

    1992-03-01

    An occurrence of Proterozoic nephelinite and basanite lavas and pyroclastic rocks and associated phonolites indicates that the processes that generate modern alkaline magmas in intraplate settings were operative in the Early Proterozoic. These lavas occur near the top of a 1.9 Ga continental-margin sequence in the Cape Smith fold and thrust belt of northern Quebec. The lavas are classified as nephelinites, basanites, and phonolites on the basis of high field strength and rare earth element contents, although large ion lithophile elements, including alkalis, appear to have been strongly depleted by greenschist facies metamorphism and alteration. Certain major elements define trends consistent with low-pressure fractionation dominated by clinopyroxene, which is the only mafic phenocryst present in the lavas. The mafic and felsic lavas have identical 143Nd/144Nd ratios, consistent with consanguinity and a lack of contamination by older crust of the Superior province. Values for ɛNd (1.96 Ga) of +2 represent an enriched mantle source relative to +4 to +5 for the contemporaneous mid-oceanic-ridge basalt reservoir.

  18. Origins--2.

    ERIC Educational Resources Information Center

    Fergusson, J. E.

    1979-01-01

    The abundance and distribution of the elements on the earth can, in part, be explained in terms of chemical properties such as reduction potentials, solubilities, ionic size, densities, melting points, and pH. The relative abundance of the elements, their distribution, and their concentration, particularly on the earth, are discussed. (Author/BB)

  19. Radar Images of the Earth and the World Wide Web

    NASA Technical Reports Server (NTRS)

    Chapman, B.; Freeman, A.

    1995-01-01

    A perspective of NASA's Jet Propulsion Laboratory as a center of planetary exploration, and its involvement in studying the earth from space is given. Remote sensing, radar maps, land topography, snow cover properties, vegetation type, biomass content, moisture levels, and ocean data are items discussed related to earth orbiting satellite imaging radar. World Wide Web viewing of this content is discussed.

  20. Urban fifth graders' connections-making between formal earth science content and their lived experiences

    NASA Astrophysics Data System (ADS)

    Brkich, Katie Lynn

    2014-03-01

    Earth science education, as it is traditionally taught, involves presenting concepts such as weathering, erosion, and deposition using relatively well-known examples—the Grand Canyon, beach erosion, and others. However, these examples—which resonate well with middle- and upper-class students—ill-serve students of poverty attending urban schools who may have never traveled farther from home than the corner store. In this paper, I explore the use of a place-based educational framework in teaching earth science concepts to urban fifth graders and explore the connections they make between formal earth science content and their lived experiences using participant-driven photo elicitation techniques. I argue that students are able to gain a sounder understanding of earth science concepts when they are able to make direct observations between the content and their lived experiences and that when such direct observations are impossible they make analogies of appearance, structure, and response to make sense of the content. I discuss additionally the importance of expanding earth science instruction to include man-made materials, as these materials are excluded traditionally from the curriculum yet are most immediately available to urban students for examination.

  1. Assessment of Bioavailable Concentrations of Germanium and Rare Earth Elements in the Rhizosphere of White Lupin (Lupinus albus L.)

    NASA Astrophysics Data System (ADS)

    Wiche, Oliver; Fischer, Ronny; Moschner, Christin; Székely, Balázs

    2015-04-01

    Concentrations of Germanium (Ge) and Rare Earth Elements in soils are estimated at 1.5 mg kg -1 (Ge), 25 mg kg -1 (La) and 20 mg kg -1 (Nd), which are only roughly smaller than concentrations of Pb and Zn. Germanium and rare earth elements are thus not rare but widely dispersed in soils and therefore up to date, only a few minable deposits are available. An environmental friendly and cost-effective way for Ge and rare earth element production could be phytomining. However, the most challenging part of a phytomining of these elements is to increase bioavailable concentrations of the elements in soils. Recent studies show, that mixed cultures with white lupine or other species with a high potential to mobilize trace metals in their rhizosphere due to an acidification of the soil and release of organic acids in the root zone could be a promising tool for phytomining. Complexation of Ge and rare earth elements by organic acids might play a key role in controlling bioavailability to plants as re-adsorption on soil particles and precipitation is prevented and thus, concentrations in the root zone of white lupine increase. This may also allow the complexes to diffuse along a concentration gradient to the roots of mixed culture growing species leading to enhanced plant uptake. However, to optimize mixed cultures it would be interesting to know to which extend mobilization of trace metals is dependent from chemical speciation of elements in soil due to the interspecific interaction of roots. A method for the identification of complexes of germanium and rare earth elements with organic acids, predominantly citric acid in the rhizosphere of white lupine was developed and successfully tested. The method is based on coupling of liquid chromatography with ICP-MS using a zic-philic column (SeQuant). As a preliminary result, we were able to show that complexes of germanium with citric acid exist in the rhizosphere of white lupin, what may contribute to the bioavailability of this element. These studies have been carried out in the framework of the PhytoGerm project, financed by the Federal Ministry of Education and Research, Germany. The authors are grateful to students and laboratory assistants contributing in the field work and sample preparation.

  2. Multi-objective optimization of chromatographic rare earth element separation.

    PubMed

    Knutson, Hans-Kristian; Holmqvist, Anders; Nilsson, Bernt

    2015-10-16

    The importance of rare earth elements in modern technological industry grows, and as a result the interest for developing separation processes increases. This work is a part of developing chromatography as a rare earth element processing method. Process optimization is an important step in process development, and there are several competing objectives that need to be considered in a chromatographic separation process. Most studies are limited to evaluating the two competing objectives productivity and yield, and studies of scenarios with tri-objective optimizations are scarce. Tri-objective optimizations are much needed when evaluating the chromatographic separation of rare earth elements due to the importance of product pool concentration along with productivity and yield as process objectives. In this work, a multi-objective optimization strategy considering productivity, yield and pool concentration is proposed. This was carried out in the frame of a model based optimization study on a batch chromatography separation of the rare earth elements samarium, europium and gadolinium. The findings from the multi-objective optimization were used to provide with a general strategy for achieving desirable operation points, resulting in a productivity ranging between 0.61 and 0.75 kgEu/mcolumn(3), h(-1) and a pool concentration between 0.52 and 0.79 kgEu/m(3), while maintaining a purity above 99% and never falling below an 80% yield for the main target component europium. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Volatile Loss from the Proto-Lunar Disk

    NASA Astrophysics Data System (ADS)

    Albarede, F.

    2016-12-01

    Exchange of volatile elements between the Moon and Earth depends on the intrinsic volatility of each element in a H-free tenuous gas, gravitational escape, and the mean free path of elements. The H2 pressure in the gas formed by the giant impact is far too low to allow hydrodynamic entrainment of other species. A condition for gravitational escape is, therefore, that thermal velocity exceeds escape velocity at the base of the exosphere where collisions between atoms cease. Away from the Earth, the vertical pull of the disk is only a small fraction of the radial pull of the Earth, which is strong enough to keep all the elements but H and He in terrestrial orbits, and the disk exosphere is thick. The proportion of gas orbiting above the exosphere is small, its temperature has been strongly reduced by adiabatic expansion, and therefore escape of lunar volatiles to Earth should be very limited. Whether elements have been lost by escape from the Moon to Earth nevertheless can be tested by comparing the relative abundances of elements with very similar chemistry and intrinsic volatility, but with very different atomic masses. Standard sequences of mineral condensation from the Solar Nebula and T50 are irrelevant to the proto-lunar disk. Condensation temperatures in the Solar Nebula are known to vary wildly with PH2, and the PH2 of the Solar Nebula is largely insensitive to the condensation of solid mineral phases, such as those forming the mantle and core of planets. Lunar accretion follows an opposite scenario, with an early and dramatic pressure drop due to metal and silicate condensation, which is the rationale behind the intrinsic volatility scale of Albarede et al. (2015). It is observed that, despite a broad mass range, the degree of depletion in the Moon relative to the Earth or CIs is similar for chemical kins, such as the groups of alkali elements (Li, Na, K, Rb, Cs), halogens (F, Cl, Br, I), or Zn and Cd. This observation argues against massive escape of volatile elements from the Moon to Earth and against massive lunar devolatilization. It is therefore suggested that, in agreement with the mineralogy of most lunar samples, volatile depletion of the Moon is inherited from the impactor rather than a result of the impact itself. Albarède, F., E. Albalat, and C.-T. A. Lee (2015), MAPS 50(4), 568-577.

  4. Chemistry of the subalkalic silicic obsidians

    USGS Publications Warehouse

    MacDonald, Ray; Smith, Robert L.; Thomas, John E.

    1992-01-01

    Nonhydrated obsidians are quenched magmatic liquids that record in their chemical compositions details of the tectonic environment of formation and of the differentiation mechanisms that affected their subsequent evolution. This study attempts to analyze, in terms of geologic processes, the compositional variations in the subalkalic silicic obsidians (Si02≥70 percent by weight, molecular (Na2O+K20)>Al2O3). New major- and trace-element determinations of 241 samples and a compilation of 130 published major-element analyses are reported and interpreted. Obsidians from five different tectonic settings are recognized: (1) primitive island arcs, (2) mature island arcs, (3) continental margins, (4) continental interiors, and (5) oceanic extensional zones. Tectonomagmatic discrimination between these groups is successfully made on Nb-Ta, Nb-FeOt and Th-Hf-Ta plots, and compositional ranges and averages for each group are presented. The chemical differences between groups are related to the type of crust in which magmas were generated. With increasingly sialic (continental type) crust, the obsidians show overall enrichment in F, Be, Li, Mo, Nb, Rb, Sn, Ta, U, W, Zn, and the rare-earth elements, and depletion in Mg, Ca, Ba, Co, Sc, Sr, and Zr. They become more potassic, have higher Fe/Mg and F/Cl ratios, and lower Zr/Hf, Nb/Ta, and Th/U ratios. Higher values of total rare-earth elements are accompanied by light rare-earth-element enrichment and pronounced negative Eu anomalies. An attempt is made to link obsidian chemistry to genetic mechanlism. Two broad groups of rocks are distinguished: one generated where crystal-liquid processes dominated (CLPD types), which are the products of crustal anatexis, possibly under conditions of low halogen fugacity, ± crystal fractionation ± magma mixing; and a second group represented by rocks formed in the upper parts of large magma chambers by interplays of crystal fractionation, volatile transfer, magma mixing, and possibly various liquid-state differentiation mechanisms, or in other words a complex interaction of petrogenetic processes (CIPP types). Such rocks may also form by volatile-fluxed partial melting of the wallrocks, and subsequent mixing into the magma reservoir. Compositional ranges and averages for CLPD and CIPP obsidians are given. It is shown by analogy with well-documented, zoned ash-flow ruffs that obsidians fractionated by CIPP have very low Mg, P, Ba, and Sr contents, flat rare-earth-element patterns with extensive Eu anomalies, low K/Rb and Zr/Nb ratios, and relatively high Na2O/K2O ratios. There is, however, considerable compositional overlap between CLPD and CIPP obsidians. The effects of magma mixing, assimilation, and vapor-phase transport in producing compositional variations in the obsidians are briefly assessed. The geochemistry of the subalkalic silicic obsidians is described on an element-by-element basis, in order to provide a database for silicic magma compositions that will hopefully contribute to studies of granitic rocks. Attempts are also made to isolate the geochemical effects of tectonic environment and genetic mechanism for each element, by comparison with data from crystal-liquid equilibria-controlled systems, from ash-flow sheets zoned by CIPP, and from mixed-magma series. A final tabulation relates the complexities of obsidian geochemistry to all the tectonic and genetic variables.

  5. Fractionation of rare earth and other trace elements in crabs, Ucides cordatus, from a subtropical mangrove affected by fertilizer industry.

    PubMed

    Bosco-Santos, Alice; Luiz-Silva, Wanilson; Silva-Filho, Emmanoel Vieira da; Souza, Monique Dias Corrêa de; Dantas, Elton Luiz; Navarro, Margareth Sugano

    2017-04-01

    Fractionation of rare earth elements (REE) and other trace metal concentrations (Th, U, Cd, Cr, Cu, Ni, Pb, and Zn) between mangrove sediments and claw muscles and shells of male crabs (Ucides cordatus) from a subtropical estuary highly impacted by fertilizer industry activities was investigated. This is the first record of REE distribution in these organisms, and the results showed higher accumulations of these metals, U and Th in shells, probably related to the replacement of Ca during molting. Contents of Cd, Cr and Ni were similar in both tissues, but Cu, Zn and Pb were mostly accumulated in the claw muscle with concentrations above those considered safe for human consumption according to the Brazilian legislation. REE fractionation was different in the analyzed tissues being softer in the shells. The results provided evidences that the water absorbed during molting controls the chemistry of REE in shells. In contrast, the chemistry of REE in the claw muscle, in which was observed preferential absorption of light REE, is controlled by diet. REE fractionation obtained for the claw muscles was closely correlated to the observed in the contaminated substrate and in materials related to the production of phosphate fertilizers (contamination source), which supports their transference to this Ucides cordatus tissue without fractionation by the ingestion of sediments. Our results showed the potential use of crab tissues for monitoring REE and trace element sources in mangrove areas, with claw muscle exhibiting the contaminant source fingerprint. Copyright © 2016. Published by Elsevier B.V.

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

    PubMed

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

    2015-03-01

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

  7. Interaction of ultra-depleted MORBs with plagioclase: implications for CO2/Ba ratios

    NASA Astrophysics Data System (ADS)

    Shimizu, K.; Hauri, E.; Saal, A. E.; Perfit, M. R.; Hekinian, R.

    2017-12-01

    Carbon in Earth's upper mantle can significantly reduce its solidus temperature, which in turn can affect other physical properties through generation of partial melt. Carbon content in the depleted upper mantle can be estimated using ultra-depleted mid-ocean ridge basalt (UD-MORB) glasses and melt inclusions that are undersaturated in CO2. CO2 has been shown to behave as a highly incompatible element during mantle melting both through natural samples and experiments. Given its highly incompatible behavior, CO2/Ba and CO2/Nb ratios in CO2 undersaturated UD-MORBs have been used to estimate the CO2/Ba and CO2/Nb ratios and carbon content in Earth's upper mantle. A potential issue with part of this approach is the effect of melt-plagioclase chemical interaction on the CO2/Ba ratios in UD-MORBs. Plagioclase is ubiquitous in the oceanic crust and is enriched in Ba relative to other phases. Chemical interactions (assimilation and/or diffusion) between MORB melts and plagioclase bearing rocks have been shown to affect the Ba (and Sr and Eu) concentrations in MORBs, implying that such processes may also affect their CO2/Ba ratio. Hence, understanding the effect of chemical interaction between plagioclase and UD-MORBs is important for having better constraints on CO2/Ba ratio and carbon content in Earth's upper mantle. In this study, we report on the compositions of olivine-hosted melt inclusions and glasses from the Siqueiros and Garrett transform faults. A subset of melt inclusions in lavas from both transform faults show potential signatures of chemical interaction with plagioclase such as low CO2/Ba, Nb/Ba, and Nd/Sr. CO2 degassing cannot explain the low CO2/Ba ratio in the samples as they are undersaturated in CO2. To better understand the effect of chemical interaction with plagioclase on the composition of UD-MORBs, we model end-member scenarios, which are (1) assimilation of plagioclase and (2) diffusion of elements from plagioclase into the UD-MORBs. In general, the trends produced by these end-member scenarios bracket those observed in the samples (trends between CO2/Ba, Nb/Ba, and Nd/Sr as well as between Al2O3, FeO, and MgO). Hence, chemical interaction with plagioclase may affect the CO2/Ba ratio in UD-MORBs, and care should be taken to evaluate this effect using Nd/Sr and Nb/Ba ratios.

  8. Climate Discovery Online Courses for Educators from NCAR

    NASA Astrophysics Data System (ADS)

    Henderson, S.; Ward, D. L.; Meymaris, K. K.; Johnson, R. M.; Gardiner, L.; Russell, R.

    2008-12-01

    The National Center for Atmospheric Research (NCAR) has responded to the pressing need for professional development in climate and global change sciences by creating the Climate Discovery online course series. This series was designed with the secondary geoscience educator in mind. The online courses are based on current and credible climate change science. Interactive learning techniques are built into the online course designs with assignments that encourage active participation. A key element of the online courses is the creation of a virtual community of geoscience educators who exchange ideas related to classroom implementation, student assessment, and lessons plans. Geoscience educators from around the country have participated in the online courses. The ongoing interest from geoscience educators strongly suggests that the NCAR Climate Discovery online courses are a timely and needed professional development opportunity. The intent of NCAR Climate Discovery is to positively impact teachers' professional development scientifically authentic information, (2) experiencing guided practice in conducting activities and using ancillary resources in workshop venues, (3) gaining access to standards-aligned lesson plans, kits that promote hands-on learning, and scientific content that are easily implemented in their classrooms, and (4) becoming a part of a community of educators with whom they may continue to discuss the challenges of pedagogy and content comprehension in teaching climate change in the Earth system context. Three courses make up the Climate Discovery series: Introduction to Climate Change; Earth System Science - A Climate Change Perspective; and Understanding Climate Change Today. Each course, instructed by science education specialists, combines geoscience content, information about current climate research, hands-on activities, and group discussion. The online courses use the web-based Moodle courseware system (open- source software similar to Blackboard and webCT), utilizing its features to promote dialogue as well as provide rich online content and media. A key element of the online courses is the development and support of an online learning community, an essential component in successful online courses. Interactive learning techniques are built into the course designs with assignments that encourage active participation. Educators (both formal and informal) use the courses as a venue to exchange ideas and teaching resources. A unique feature of the courses is the emphasis on hands-on activities, a hallmark of our professional development efforts. This presentation will focus on the lessons learned in the development of the three online courses and our successful recruitment and retention efforts.

  9. Deep reaching fluid flow in the North East German Basin: origin and processes of groundwater salinisation

    NASA Astrophysics Data System (ADS)

    Tesmer, M.; Möller, P.; Wieland, S.; Jahnke, C.; Voigt, H.; Pekdeger, A.

    2007-11-01

    Major element chemistry, rare-earth element distribution, and H and O isotopes are conjointly used to study the sources of salinisation and interaquifer flow of saline groundwater in the North East German Basin. Chemical analyses from hydrocarbon exploration campaigns showed evidence of the existence of two different groups of brines: halite and halite Ca-Cl brines. Residual brines and leachates are identified by Br-/Cl- ratios. Most of the brines are dissolution brines of Permian evaporites. New analyses show that the pattern of rare-earth elements and yttrium (REY) are closely linked to H and O isotope distribution. Thermal brines from deep wells and artesian wells indicate isotopically evaporated brines, which chemically interacted with their aquifer environment. Isotopes and rare-earth element patterns prove that cross flow exists, especially in the post-Rupelian aquifer. However, even at depths exceeding 2,000 m, interaquifer flow takes place. The rare-earth element pattern and H and O isotopes identify locally ascending brines. A large-scale lateral groundwater flow has to be assumed because all pre-Rupelian aquifer systems to a depth of at least 500 m are isotopically characterised by Recent or Pleistocene recharge conditions.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Fluid rare earth element anlayses from wells RN-12 and RN-19, Reykjanes, Iceland

    DOE Data Explorer

    Andrew Fowler

    2015-07-24

    Results for fluid rare earth elment analyses from Reykjanes wells RN-12 and RN-19. The data have not been corrected for flashing. Samples preconcetrated using chelating resin with IDA functional group (InertSep ME-1). Analyzed using and Element magnetic sctor ICP-MS.

  12. Interactions between exogenous rare earth elements and phosphorus leaching in packed soil columns

    USDA-ARS?s Scientific Manuscript database

    Rare earth elements (REEs) increasingly used in agriculture as an amendment for crop growth may help to lessen environmental losses of phosphorus (P) from heavily fertilized soils. The vertical transport characteristics of P and REEs, lanthanum (La), neodymium (Nd), samarium (Sm), and cerium (Ce), w...

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

    EPA Science Inventory

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

  14. Phase stable rare earth garnets

    DOEpatents

    Kuntz, Joshua D.; Cherepy, Nerine J.; Roberts, Jeffery J.; Payne, Stephen A.

    2013-06-11

    A transparent ceramic according to one embodiment includes a rare earth garnet comprising A.sub.hB.sub.iC.sub.jO.sub.12, where h is 3.+-.10%, i is 2.+-.10%, and j is 3.+-.10%. A includes a rare earth element or a mixture of rare earth elements, B includes at least one of aluminum, gallium and scandium, and C includes at least one of aluminum, gallium and scandium, where A is at a dodecahedral site of the garnet, B is at an octahedral site of the garnet, and C is at a tetrahedral site of the garnet. In one embodiment, the rare earth garment has scintillation properties. A radiation detector in one embodiment includes a transparent ceramic as described above and a photo detector optically coupled to the rare earth garnet.

  15. The Influence of Novel Alloying Additions on the Performance of Magnesium Alloy AZ31B

    DTIC Science & Technology

    2013-11-01

    More recently, alloys using a variety of the rare earth elements have been developed. Typically, these alloys have shown significant improvements...in mechanical properties and to a lesser degree in corrosion performance. However, rare earth elements are often costly and heavier than Mg. Thus...1.0 0.004 Max — — Note: Fe = iron; RE = rare earth . SEM micrograph and energy-dispersive x-ray (EDX) results for selected alloys are shown in

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

    NASA Astrophysics Data System (ADS)

    Hissler, Christophe; Stille, Peter

    2015-04-01

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

  17. The Anthropo-scene: A guide for the perplexed.

    PubMed

    Lorimer, Jamie

    2017-02-01

    The scientific proposal that the Earth has entered a new epoch as a result of human activities - the Anthropocene - has catalysed a flurry of intellectual activity. I introduce and review the rich, inchoate and multi-disciplinary diversity of this Anthropo-scene. I identify five ways in which the concept of the Anthropocene has been mobilized: scientific question, intellectual zeitgeist, ideological provocation, new ontologies and science fiction. This typology offers an analytical framework for parsing this diversity, for understanding the interactions between different ways of thinking in the Anthropo-scene, and thus for comprehending elements of its particular and peculiar sociabilities. Here I deploy this framework to situate Earth Systems Science within the Anthropo-scene, exploring both the status afforded science in discussions of this new epoch, and the various ways in which the other means of engaging with the concept come to shape the conduct, content and politics of this scientific enquiry. In conclusion the paper reflects on the potential of the Anthropocene for new modes of academic praxis.

  18. The Organic Composition of Carbonaceous Meteorites: The Evolutionary Story Ahead of Biochemistry

    PubMed Central

    Pizzarello, Sandra; Shock, Everett

    2010-01-01

    Carbon-containing meteorites provide a natural sample of the extraterrestrial organic chemistry that occurred in the solar system ahead of life's origin on the Earth. Analyses of 40 years have shown the organic content of these meteorites to be materials as diverse as kerogen-like macromolecules and simpler soluble compounds such as amino acids and polyols. Many meteoritic molecules have identical counterpart in the biosphere and, in a primitive group of meteorites, represent the majority of their carbon. Most of the compounds in meteorites have isotopic compositions that date their formation to presolar environments and reveal a long and active cosmochemical evolution of the biogenic elements. Whether this evolution resumed on the Earth to foster biogenesis after exogenous delivery of meteoritic and cometary materials is not known, yet, the selective abundance of biomolecule precursors evident in some cosmic environments and the unique L-asymmetry of some meteoritic amino acids are suggestive of their possible contribution to terrestrial molecular evolution. PMID:20300213

  19. Sound velocity measurements in dhcp-FeH up to 70 GPa with inelastic X-ray scattering: Implications for the composition of the Earth's core

    NASA Astrophysics Data System (ADS)

    Shibazaki, Yuki; Ohtani, Eiji; Fukui, Hiroshi; Sakai, Takeshi; Kamada, Seiji; Ishikawa, Daisuke; Tsutsui, Satoshi; Baron, Alfred Q. R.; Nishitani, Naoya; Hirao, Naohisa; Takemura, Kenichi

    2012-01-01

    We have determined the density evolution of the sound velocity of dhcp-FeH x ( x ≈ 1) up to 70 GPa at room temperature, by inelastic X-ray scattering and by X-ray diffraction. We find that the variation of VP with density is different for the ferromagnetic and nonmagnetic dhcp-FeH x, and that only nonmagnetic dhcp-FeH x follows Birch's law. Combining our results with Birch's law for iron and assuming an ideal two-component mixing model, we obtain an upper bound of the hydrogen content in the Earth's inner core, 0.23(6) wt.% H, corresponding to FeH 0.13(3). The iron alloy with 0.23(6) wt.% H can satisfy the density, and compressional and shear sound velocities of the PREM inner core, assuming that there are no other light elements in the inner core.

  20. Distribution of Alkalis (Na, Cs, Rb) Between Silicate and Sulfide: Implications for Planetary Volatile Depletion

    NASA Technical Reports Server (NTRS)

    Boujibar, A.; Fei, Y.; Righter, K.; Du, Z.; Bullock, E.

    2018-01-01

    The abundances of volatile elements in the Earth's mantle are correlated with their temperatures of condensation. This depletion can be due to either incomplete condensation of the elements during the nebula condensation or evaporation processes during planetary growth. Elements that have affinities with metals (siderophile) and sulfides (chalcophile) are additionally depleted due to their segregation into the core. Therefore, study of lithophile elements could be useful to isolate processes of volatilization and their effect on the abundance of the elements in the Earth's mantle. However, the correlation of these lithophile elements including alkali elements, with their temperatures of condensation shows a significant scatter, which is difficult to reconcile with a depletion by vaporization or incomplete condensation alone.

  1. Trace element contaminants in mineral fertilizers used in Iran.

    PubMed

    Latifi, Zahra; Jalali, Mohsen

    2018-05-25

    The application of mineral fertilizers which have contaminants of trace elements may impose concern regarding the entry and toxic accumulation of these elements in agro-ecosystems. In this study, 57 mineral fertilizers (nitrogen, potassium, phosphate, and compound fertilizers) distributed in Iran were analyzed for their contents of Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn, and Fe. The results revealed that the contents of these trace elements varied considerably depending on the type of the element and the fertilizer. Among these elements, Fe displayed the highest average content, whereas Cd showed the lowest. Generally, the trace element contents in P-containing fertilizers were higher than those in nitrogen and potassium fertilizers. The mean values of trace elements (mg kg -1 ) in P-containing fertilizers were 4.0 (Cd), 5.5 (Co), 35.7 (Cr), 24.4 (Cu), 272 (Mn), 14.3 (Ni), 6.0 (Pb), 226 (Zn), and 2532 (Fe). Comparing trace element contents to limit values set by the German Fertilizer Ordinance showed that the mean contents of potentially toxic trace elements, such as Cd and Pb, were lower than their limit values in all groups of fertilizers. On the other hand, while a number of fertilizers contained a high content of some essential trace elements, particularly Fe, they were not labeled as such.

  2. Siderophile and chalcophile element abundances in oceanic basalts, Pb isotope evolution and growth of the earth's core

    NASA Technical Reports Server (NTRS)

    Newsom, H. E.; White, W. M.; Jochum, K. P.; Hofmann, A. W.

    1986-01-01

    The hypothesis that the mantle Pb isotope ratios reflect continued extraction of Pb into the earth's core over geologic time is evaluated by studying the depeletion of chalcophile and siderophile elements in the mantle. Oceanic basalt samples are analyzed in order to determine the Pb, Sr, and Nd isotropic compositions and the abundances of siderophile and chalcophile elements and incompatible lithophile elements. The data reveal that there is no systematic variation of siderophile or chalcophile element abundances relative to abundances of lithophile elements and the Pb/Ce ratio of the mantle is constant. It is suggested that the crust formation involves nonmagmatic and magmatic processes.

  3. Influence of rare earth content on Mm-based AB 5 metal hydride alloys for Ni-MH batteries-An X-ray fluorescence study

    NASA Astrophysics Data System (ADS)

    Ananth, M. V.; Raju, M.; Manimaran, K.; Balachandran, G.; Nair, Lekshmi M.

    AB 5-type MH alloys with Mm (Misch metal) as the A part (with varied rare earth contents in Mm) were investigated for rare earth by XRF analysis and battery performance by life cycle tests with an objective of understanding the influence of rare earth content on electrochemical hydrogen storage. The La/Ce ratio was found to vary from 0.51 to 18.73. The capacity output varied between 179 and 266 mAh g -1. The results show that the La/Ce ratio has a strong influence on the performance, with the best performance realized with samples having an La/Ce ratio of around 12. La enhancement facilitates easy activation due to refinement in grain size and interstitial dimensions. Also, an orderly influence on crystalline structure could be seen. The study demonstrates that the rare earth content is an essential factor in determining the maximum capacity output because of its influence on crystal orientation as well as an increase in the radius of the interstitials, lattice constants and cell volumes.

  4. Geochemistry of komatiites and basalts from the Rio das Velhas and Pitangui greenstone belts, São Francisco Craton, Brazil: Implications for the origin, evolution, and tectonic setting

    NASA Astrophysics Data System (ADS)

    Verma, Sanjeet K.; Oliveira, Elson P.; Silva, Paola M.; Moreno, Juan A.; Amaral, Wagner S.

    2017-07-01

    The Neoarchean Rio das Velhas and Pitangui greenstone belts are situated in the southern São Francisco Craton, Minas Gerais, Brazil. These greenstone belts were formed between ca. 2.79-2.73 Ga, and consist mostly of mafic to ultramafic volcanics and clastic sediments, with minor chemical sediments and felsic volcanics that were metamorphosed under greenschist facies. Komatiites are found only in the Rio das Velhas greenstone belt, which is composed of high-MgO volcanic rocks that have been identified as komatiites and high-Mg basalts, based on their distinctive geochemical characteristics. The Rio das Velhas komatiites are composed of tremolite + actinolite + serpentine + albite with a relict spinifex-texture. The Rio das Velhas komatiites have a high magnesium content ((MgO)adj ≥ 28 wt.%), an Al-undepleted Munro-type [(Al2O3/TiO2)adj and (CaO/Al2O3)adj] ratio ranging from 27 to 47 and 0.48 to 0.89, relatively low abundances of incompatible elements, a depletion of light rare earth elements (LREE), a pattern of non-fractionated heavy rare- earth elements (HREE), and a low (Gd/Yb)PM ratio (≤ 1.0). Negative Ce anomalies suggest that alteration occurred during greenschist facies metamorphism for the komatiites and high-Mg basalts. The low [(Gd/Yb)PM < 1.0] and [(CaO/Al2O3)adj < 0.9)], high [(Al2O3/TiO2)adj > 18] and high HREE, Y, and Zr content suggest that the Rio das Velhas komatiites were derived from the shallow upper mantle without garnet involvement in the residue. The chemical compositions [(Al2O3/TiO2)adj, (FeO)adj, (MgO)adj, (CaO/Al2O3)adj, Na, Th, Ta, Ni, Cr, Zr, Y, Hf, and REE] indicate that the formation of the komatiites, high-Mg basalts and basalts occurred at different depths and temperatures in a heterogeneous mantle. The komatiites and high-Mg basalts melted at liquidus temperatures of 1450-1550 °C. The Pitangui basalts are enriched in the highly incompatible LILE (large-ion lithophile elements) relative to the moderately incompatible HFS (high field strength) elements. The Zr/Th ratio ranging from 76 to 213 and the relationship between the Nb/Th and Th/Yb ratios indicate that there is no crustal contamination in the Pitangui greenstone basalts. New multi-dimensional discrimination diagrams and conventional normalized multi-element diagrams indicate an island arc (IA) setting for the komatiites and high-Mg basalts from the Rio das Velhas and a mid ocean-ridge (MOR) to IA setting for the basalts from the Pitangui greenstone belts.

  5. Core layering

    NASA Astrophysics Data System (ADS)

    Jacobson, S. A.; Rubie, D. C.; Hernlund, J. W.; Morbidelli, A.

    2015-12-01

    We have created a planetary accretion and differentiation model that self-consistently builds and evolves Earth's core. From this model, we show that the core grows stably stratified as the result of rising metal-silicate equilibration temperatures and pressures, which increases the concentrations of light element impurities into each newer core addition. This stable stratification would naturally resist convection and frustrate the onset of a geodynamo, however, late giant impacts could mechanically mix the distinct accreted core layers creating large homogenous regions. Within these regions, a geodynamo may operate. From this model, we interpret the difference between the planetary magnetic fields of Earth and Venus as a difference in giant impact histories. Our planetary accretion model is a numerical N-body integration of the Grand Tack scenario [1]—the most successful terrestrial planet formation model to date [2,3]. Then, we take the accretion histories of Earth-like and Venus-like planets from this model and post-process the growth of each terrestrial planet according to a well-tested planetary differentiation model [4,5]. This model fits Earth's mantle by modifying the oxygen content of the pre-cursor planetesimals and embryos as well as the conditions of metal-silicate equilibration. Other non-volatile major, minor and trace elements included in the model are assumed to be in CI chondrite proportions. The results from this model across many simulated terrestrial planet growth histories are robust. If the kinetic energy delivered by larger impacts is neglected, the core of each planet grows with a strong stable stratification that would significantly impede convection. However, if giant impact mixing is very efficient or if the impact history delivers large impacts late, than the stable stratification can be removed. [1] Walsh et al. Nature 475 (2011) [2] O'Brien et al. Icarus 223 (2014) [3] Jacobson & Morbidelli PTRSA 372 (2014) [4] Rubie et al. EPSL 301 (2011) [5] Rubie et al. Icarus 248 (2015)

  6. Volatile Content of 4-Vesta: Evidence from Unequilibrated Eucrites

    NASA Technical Reports Server (NTRS)

    Sarafian, A. R.; Nielsen, S. G.; Marschall, H. R.; Gaetani, G. A.; Hauri, E. H.; Righter, K.; Berger, E. L.

    2017-01-01

    Eucrites are a class of basaltic meteorites that, along with the howardites and diogenites, likely derive from the asteroid 4-Vesta. This asteroid is depleted in moderately volatile elements relative to the Earth and carbonaceous chondrites. Extrapolation of this depletion trend predicts that bulk silicate 4-Vesta (BSV) contains at most 250-1000 µg/g H2O, which is approximately a factor of two lower than the H2O content of Earth. To obtain more accurate H2O and F estimates for BSV, we examined four unequilibrated antarctic meteorites, Yamato(Y)-793548, Y-82210, Y-75011, and Y-74450, by EPMA and SIMS. Pyroxenes contain MgO-rich cores and FeO-rich rims, consistent with primary magmatic zoning. Volatile concentrations generally follow patterns expected for growth zoning with lower values in the cores and higher in the rims. These features indicate that thermal metamorphism and other post-crystallization processes did not significantly perturb the volatile contents of these unequilibrated eucrite pyroxenes. We used these data to derive best estimates for the BSV H2O and F content based on experimentally determined pyroxene-melt partition coefficients and models for magma generation on Vesta. In addition, we measured D/H in the early crystallizing pyroxenes and late crystallzing apatites. We find that the D/H of pyroxene and apatite are within error of one another as well as previous measurements of apatite in equilibrated eucrites. These results imply that degassing was minimal or did not fractionate D/H. Degassing may have been limited if eucrites were shallowly emplaced sills or dykes, or the total H2O content of the magmas was too low for vapor saturation. An alternative mechanism for limited D/H fractionation is that degassing did occur, but the H2/H2O of the exsolved vapor was approximately 15:85, as predicted from experiments.

  7. Next-generation Digital Earth.

    PubMed

    Goodchild, Michael F; Guo, Huadong; Annoni, Alessandro; Bian, Ling; de Bie, Kees; Campbell, Frederick; Craglia, Max; Ehlers, Manfred; van Genderen, John; Jackson, Davina; Lewis, Anthony J; Pesaresi, Martino; Remetey-Fülöpp, Gábor; Simpson, Richard; Skidmore, Andrew; Wang, Changlin; Woodgate, Peter

    2012-07-10

    A speech of then-Vice President Al Gore in 1998 created a vision for a Digital Earth, and played a role in stimulating the development of a first generation of virtual globes, typified by Google Earth, that achieved many but not all the elements of this vision. The technical achievements of Google Earth, and the functionality of this first generation of virtual globes, are reviewed against the Gore vision. Meanwhile, developments in technology continue, the era of "big data" has arrived, the general public is more and more engaged with technology through citizen science and crowd-sourcing, and advances have been made in our scientific understanding of the Earth system. However, although Google Earth stimulated progress in communicating the results of science, there continue to be substantial barriers in the public's access to science. All these factors prompt a reexamination of the initial vision of Digital Earth, and a discussion of the major elements that should be part of a next generation.

  8. The chlorine abundance of Earth: Implications for a habitable planet

    NASA Astrophysics Data System (ADS)

    Sharp, Z. D.; Draper, D. S.

    2013-05-01

    The Cl, Br and I contents of Earth are depleted by a factor of 10 relative to predicted values from chondritic and solar abundances. Possible explanations for the apparent discrepancy include (1) unrecognized sequestration of Cl in the core, (2) a much higher nebular volatility than normally presumed or (3) a preferential loss of the heavy halogens during planetary accretion. We tested the first assumption by conducting high pressure-temperature equilibration experiments between silicate and metal. At 15 GPa and 1900 °C, the DCl(metal-silicate) value for Cl is less than 0.007, indicating that the core is not a significant reservoir for Cl. The concentration of Cl in all chondritic classes follows a depletion trend very similar to that of Na and Mn, arguing against a low condensation temperature for Cl. Instead, we propose that the depletion of the heavy halogens is due to their unique hydrophilic behavior. Almost half of Earth's Cl and Br inventory resides in the ocean and evaporites, demonstrating the unique affinity for aqueous solutions for these elements. During planetary accretion, there would have been a strong sequestration of halogens into the crustal reservoir. 'Collisional erosion' during planetary accretion provides a mechanism that would uniquely strip the heavy halogens out of an accreting Earth. Had such loss not occurred, the salinity of the oceans would be 10× the present value, and complex life would probably never have evolved.

  9. Trace element contents in fine particulate matter (PM2.5) in urban school microenvironments near a contaminated beach with mine tailings, Chañaral, Chile.

    PubMed

    Mesías Monsalve, Stephanie; Martínez, Leonardo; Yohannessen Vásquez, Karla; Alvarado Orellana, Sergio; Klarián Vergara, José; Martín Mateo, Miguel; Costilla Salazar, Rogelio; Fuentes Alburquenque, Mauricio; Cáceres Lillo, Dante D

    2018-06-01

    Air quality in schools is an important public health issue because children spend a considerable part of their daily life in classrooms. Particulate size and chemical composition has been associated with negative health effects. We studied levels of trace element concentrations in fine particulate matter (PM 2.5 ) in indoor versus outdoor school settings from six schools in Chañaral, a coastal city with a beach severely polluted with mine tailings. Concentrations of trace elements were measured on two consecutive days during the summer and winter of 2012 and 2013 and determined using X-ray fluorescence. Source apportionment and element enrichment were measured using principal components analysis and enrichment factors. Trace elements were higher in indoor school spaces, especially in classrooms compared with outdoor environments. The most abundant elements were Na, Cl, S, Ca, Fe, K, Mn, Ti, and Si, associated with earth's crust. Conversely, an extremely high enrichment factor was determined for Cu, Zn, Ni and Cr; heavy metals associated with systemic and carcinogenic risk effects, whose probably origin sources are industrial and mining activities. These results suggest that the main source of trace elements in PM 2.5 from these school microenvironments is a mixture of dust contaminated with mine tailings and marine aerosols. Policymakers should prioritize environmental management changes to minimize further environmental damage and its direct impact on the health of children exposed.

  10. [Effects of rare earth elements on soil fauna community structure and their ecotoxicity to Holotrichia parallela].

    PubMed

    Li, Guiting; Jiang, Junqi; Chen, Jie; Zou, Yunding; Zhang, Xincai

    2006-01-01

    By the method of OECD filter paper contact, this paper studied the effects of applied rare earth elements on soil fauna community structure and their ecological toxicity to Holotrichia parallela in bean field. The results showed that there were no significant differences between the treatments and the control in soil fauna species, quantity of main species, and diversity index. Urgent and chronic toxic test showed that the differences between the treatments and the control were not significant. It was suggested that within the range of test dosages, rare earth elements had little ecological toxicity to Holotrichia parallela, and did not change the soil fauna community structure.

  11. Metasomatic Control of Water in Garnet and Pyroxene from Kaapvaal Craton Mantle Xenoliths

    NASA Technical Reports Server (NTRS)

    Peslier, Anne H.; Woodland, Alan B.; Bell, David R.; Lazarov, Marina; Lapen, Thomas J.

    2012-01-01

    Fourier transform infrared spectrometry (FTIR) and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) were used to determine water, rare earth (REE), lithophile (LILE), and high field strength (HFSE) element contents in garnet and pyroxene from mantle xenoliths, Kaapvaal craton, southern Africa. Water enters these nominally anhydrous minerals as protons bonded to structural oxygen in lattice defects. Pyroxene water contents (150-400 ppm in clinopyroxene; 40-250 ppm in orthopyroxene) correlate with their Al, Fe, Ca and Na and are homogeneous within a mineral grains and a xenolith. Garnets from Jagersfontein are chemically zoned for Cr, Ca, Ti and water contents. Garnets contain 0 to 20 ppm H2 Despite the fast diffusion rate of H in mantle m inerals, the observations above indicate that the water contents of mantle xenolith minerals were not disturbed during kimberlite entrainment and that the measured water data represent mantle values. Trace elements in all minerals show various degrees of light REE and LILE enrichments indicative of minimal to strong metasomatism. Water contents of peridotite minerals from the Kaapvaal lithosphere are not related to the degree of depletion of the peridotites. Instead, metasomatism exerts a clear control on the amount of water of mantle minerals. Xenoliths from each location record specific types of metasomatism with different outcomes for the water contents of mantle minerals. At pressures . 5.5 GPa, highly alkaline melts metasomatized Liqhobong and Kimberley peridotites, and increased the water contents of their olivine, pyroxenes and garnet. At higher pressures, the circulation of ultramafic melts reacting with peridotite resulted in co-variation of Ca, Ti and water at the edge of garnets at Jagersfontein, overall decreasing their water content, and lowered the water content of olivines at Finsch Mine. The calculated water content of these melts varies depending on whether the water content of the peridotite (2 wt% HO. 2O) or individual m inerals (<0.5-13 wt% H2O) are used, and also depend on the mineral-melt water partition coefficients. These metasomatic events are thought to have occurred during the Archean and Proterozoic, meaning that the water contents measured here have been preserved since that time and can be used to investigate viscocity and longevity of cratonic mantle roots.

  12. Using News Media Databases (LexisNexis) To Identify Relevant Topics For Introductory Earth Science Classes

    NASA Astrophysics Data System (ADS)

    Cervato, C.; Jach, J. Y.; Ridky, R.

    2003-12-01

    Introductory Earth science courses are undergoing pedagogical changes in universities across the country and are focusing more than ever on the non-science majors. Increasing enrollment of non-science majors in these introductory Earth science courses demands a new look at what is being taught and how the content can be objectively chosen. Assessing the content and effectiveness of these courses requires a quantitative investigation of introductory Earth science topics and their relevance to current issues and concerns. Relevance of Earth science topics can be linked to improved students' attitude toward science and a deeper understanding of concepts. We have used the Internet based national news search-engine LexisNexis Academic Universe (http://www.lexisnexis.org/) to select the occurrence of Earth science terms over the last 12 months, five and ten years both regionally and nationally. This database of term occurrences is being used to examine how Earth sciences have evolved in the news through the last 10 years and is also compared with textbook contents and course syllabi from randomly selected introductory earth science courses across the nation. These data constitute the quantitative foundation for this study and are being used to evaluate the relevance of introductory earth science course content. The relevance of introductory course content and current real-world issues to student attitudes is a crucial factor when considering changes in course curricula and pedagogy. We have examined students' conception of the nature of science and attitudes towards science and learning science using a Likert-scale assessment instrument in the fall 2002 Geology 100 classes at Iowa State University. A pre-test and post-test were administered to see if the students' attitudes changed during the semester using as reference a control group comprised of geoscience undergraduate and graduate students, and faculty. The results of the attitude survey have been analyzed in terms of student demographics and socioeconomic variables (e.g., year in school, gender).

  13. Responses of antioxidant systems after exposition to rare earths and their role in chilling stress in common duckweed (Lemna minor L.): a defensive weapon or a boomerang?

    PubMed

    Ippolito, M P; Fasciano, C; d'Aquino, L; Morgana, M; Tommasi, F

    2010-01-01

    Extensive agriculture application of rare earth elements (REEs) in Far East countries might cause spreading of these metals in aquatic and terrestrial ecosystems, thus inducing a growing concern about their environmental impact. In this work the effects of a mix of different REE nitrate (RE) and of lanthanum nitrate (LA) on catalase and antioxidant systems involved in the ascorbate-glutathione cycle were investigated in common duckweed Lemna minor L. The results indicated that L. minor shows an overall good tolerance to the presence of REEs in the media. Treatments at concentrations up to 5 mM RE and 5 mM LA did not cause either visible symptoms on plants or significant effects on reactive oxygen species (ROS) production, chlorophyll content, and lipid peroxidation. Toxic effects were observed after 5 days of exposition to 10 mM RE and 10 mM LA. A remarkable increase in glutathione content as well as in enzymatic antioxidants was observed before the appearance of the stress symptoms in treated plants. Duckweed plants pretreated with RE and LA were also exposed to chilling stress to verify whether antioxidants variations induced by RE and LA improve plant resistance to the chilling stress. In pretreated plants, a decrease in ascorbate and glutathione redox state and in chlorophyll content and an increase in lipid peroxidation and ROS production levels were observed. The use of antioxidant levels as a stress marker for monitoring REE toxicity in aquatic ecosystems by means of common duckweed is discussed.

  14. Positive anomalous concentrations of Pb in some gabbroic rocks of Afikpo basin southeastern Nigeria.

    PubMed

    Onwualu-John, J N

    2016-08-01

    Gabbroic rocks have intruded the sedimentary sequence at Ameta in Afikpo basin southeastern Nigeria. Petrographic and geochemical features of the rocks were studied in order to evaluate their genetic and geotectonic history. The petrographic results show that the rocks contain plagioclase, olivine, pyroxene, biotite, iron oxide, and traces of quartz in three samples. Major element characteristics show that the rocks are subalkaline. In addition, the rocks have geochemical characteristics similar to basaltic andesites. The trace elements results show inconsistent concentrations of high field strength elements (Zr, Nb, Th, Ta), moderate enrichment of large-ion lithophile elements (Rb, Sr, Ba) and low concentrations of Ni and Cr. Rare earth element results show that the rocks are characterized by enrichment of light rare earth elements, middle rare earth elements enrichment, and depletion of heavy rare earth elements with slight positive europium anomalies. Zinc concentrations are within the normal range in basaltic rocks. There are extremely high concentrations of Pb in three of the rock samples. The high Pb concentrations in some of these rocks could be as a result of last episodes of magmatic crystallization. The rocks intruded the Asu River Group; organic components in the sedimentary sequence probably contain Pb which has been assimilated into the magma at the evolutionary stage of the magma. Weathering of some rocks that contain galena could lead to an increase in the concentration of lead in the gabbroic rocks, especially when the migration and crystallization of magma take place in an aqueous environment. Nevertheless, high concentration of lead is hazardous to health and environment.

  15. Toward understanding early Earth evolution: Prescription for approach from terrestrial noble gas and light element records in lunar soils

    PubMed Central

    Ozima, Minoru; Yin, Qing-Zhu; Podosek, Frank A.; Miura, Yayoi N.

    2008-01-01

    Because of the almost total lack of geological record on the Earth's surface before 4 billion years ago, the history of the Earth during this period is still enigmatic. Here we describe a practical approach to tackle the formidable problems caused by this lack. We propose that examinations of lunar soils for light elements such as He, N, O, Ne, and Ar would shed a new light on this dark age in the Earth's history and resolve three of the most fundamental questions in earth science: the onset time of the geomagnetic field, the appearance of an oxygen atmosphere, and the secular variation of an Earth–Moon dynamical system. PMID:19001263

  16. Volatile accretion history of the Earth.

    PubMed

    Wood, B J; Halliday, A N; Rehkämper, M

    2010-10-28

    It has long been thought that the Earth had a protracted and complex history of volatile accretion and loss. Albarède paints a different picture, proposing that the Earth first formed as a dry planet which, like the Moon, was devoid of volatile constituents. He suggests that the Earth's complement of volatile elements was only established later, by the addition of a small veneer of volatile-rich material at ∼100 Myr (here and elsewhere, ages are relative to the origin of the Solar System). Here we argue that the Earth's mass balance of moderately volatile elements is inconsistent with Albarède's hypothesis but is well explained by the standard model of accretion from partially volatile-depleted material, accompanied by core formation.

  17. Yttrium and rare earth stabilized fast reactor metal fuel

    DOEpatents

    Guon, Jerold; Grantham, LeRoy F.; Specht, Eugene R.

    1992-01-01

    To increase the operating temperature of a reactor, the melting point and mechanical properties of the fuel must be increased. For an actinide-rich fuel, yttrium, lanthanum and/or rare earth elements can be added, as stabilizers, to uranium and plutonium and/or a mixture of other actinides to raise the melting point of the fuel and improve its mechanical properties. Since only about 1% of the actinide fuel may be yttrium, lanthanum, or a rare earth element, the neutron penalty is low, the reactor core size can be reduced, the fuel can be burned efficiently, reprocessing requirements are reduced, and the nuclear waste disposal volumes reduced. A further advantage occurs when yttrium, lanthanum, and/or other rare earth elements are exposed to radiation in a reactor, they produce only short half life radioisotopes, which reduce nuclear waste disposal problems through much shorter assured-isolation requirements.

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

    USDA-ARS?s Scientific Manuscript database

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

  19. Tracing sediment movement on semi-arid watershed using Rare Earth Elements 1988

    USDA-ARS?s Scientific Manuscript database

    A multi-tracer method employing rare earth elements (REE) was used to determine sediment yield and to track sediment movement in a small semiarid watershed. A 0.33 ha watershed near Tombstone, AZ was divided into five morphological units, each tagged with one of five REE oxides. Relative contributi...

  20. Preliminary study on using rare earth elements to trace non-point source phosphorous loss

    USDA-ARS?s Scientific Manuscript database

    The environmental fate of phosphorus (P) is of concern as P is a primary cause of freshwater eutrophication. Rare earth elements (REEs) have been successfully used in the analysis of soil erosion and pollutant sources, as well as in the analysis of mineral genesis. To better understand the potential...

  1. Carbon and sulfur budget of the silicate Earth explained by accretion of differentiated planetary embryos

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Dasgupta, Rajdeep; Tsuno, Kyusei; Monteleone, Brian; Shimizu, Nobumichi

    2016-10-01

    The abundances of volatile elements in the Earth's mantle have been attributed to the delivery of volatile-rich material after the main phase of accretion. However, no known meteorites could deliver the volatile elements, such as carbon, nitrogen, hydrogen and sulfur, at the relative abundances observed for the silicate Earth. Alternatively, Earth could have acquired its volatile inventory during accretion and differentiation, but the fate of volatile elements during core formation is known only for a limited set of conditions. Here we present constraints from laboratory experiments on the partitioning of carbon and sulfur between metallic cores and silicate mantles under conditions relevant for rocky planetary bodies. We find that carbon remains more siderophile than sulfur over a range of oxygen fugacities; however, our experiments suggest that in reduced or sulfur-rich bodies, carbon is expelled from the segregating core. Combined with previous constraints, we propose that the ratio of carbon to sulfur in the silicate Earth could have been established by differentiation of a planetary embryo that was then accreted to the proto-Earth. We suggest that the accretion of a Mercury-like (reduced) or a sulfur-rich (oxidized) differentiated body--in which carbon has been preferentially partitioned into the mantle--may explain the Earth's carbon and sulfur budgets.

  2. Rare earth element scavenging in seawater

    NASA Astrophysics Data System (ADS)

    Byrne, Robert H.; Kim, Ki-Hyun

    1990-10-01

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

  3. Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets.

    PubMed

    Imashuku, Susumu; Wagatsuma, Kazuaki; Kawai, Jun

    2016-02-01

    Scanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium-iron-boron (NdFeB) and samarium-cobalt (Sm-Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm-Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.

  4. Alignment of Content and Pedagogy in an Earth Systems Course for Pre-Service Middle School Teachers

    NASA Astrophysics Data System (ADS)

    Cole, T.; Teed, R.; Slattery, W.

    2006-12-01

    In 2003 the Ohio Department of Education developed the Ohio K-12 Science Content Standards. These new science standards substantially tracked the goals and objectives of The National Research Council's National Science Education Standards. The Ohio K-12 Science Content Standards followed the National Standards in the content areas of Physical Science, Life Science and Earth and Space Science. At the same time, the state's K-12 schools were gearing up for a new high school graduation requirement, the successful passing of a high-stakes Ohio Graduation Test, given during a student's tenth grade year. Earth and Space science questions make up approximately one third of the science test items. To make it more likely that teachers have the requisite science content knowledge Ohio has recently changed from certification of K-12 teachers to a more content rich licensure standard. This new licensure requirement splits the older certification designation of K-8 into the elementary and middle school licensure areas. Under the new licensure requirements middle school licensure candidates wishing to earn a science concentration now have to take 15 semester hours of content class work in Science. The Ohio Department of Education has strongly suggested that teacher preparation institutions develop new courses for middle school educators in all four areas of concentration, including science. In response to this call for new courses science education faculty in all science areas worked together to develop a comprehensive suite of courses that would target the science content standards guidelines in the state and national standards. The newly developed Earth and Space science course is titled Earth Systems. The course carries 4.5quarter hours of credit and is intended expressly for pre-service middle school (grades 4- 9) science teachers. The content is structured around three modules of study that are designed to develop interdisciplinary science content within the context of past, present and future Earth Systems science. Because the course is created for pre-service teachers, the class models the jigsaw teaching technique, an effective and age-appropriate method of science instruction. This enables pre-service teachers to experience a technique they can use in their own classroom. Course content is aligned with all state and national 4-10 Earth/Space Science standards, which supports pre- service Middle School Science teachers by covering the content areas tested in the Praxis Middle School Science test, a requirement for graduation with licensure from Wright State University. It also helps the pre- service teachers gain experience with the content that they will need to teach to their K-12 students, so they will be able to pass the high-stakes Ohio Graduation Test. Assessment of the Earth Systems course suggests that the course leads to increased science content knowledge that leads to success in passing the Praxis Middle Childhood Science Test, and that the pedagogy modeled in the course is used by the pre- service teachers in their own K-12 teaching upon graduation.

  5. Seismic sources

    DOEpatents

    Green, Michael A.; Cook, Neville G. W.; McEvilly, Thomas V.; Majer, Ernest L.; Witherspoon, Paul A.

    1992-01-01

    Apparatus is described for placement in a borehole in the earth, which enables the generation of closely controlled seismic waves from the borehole. Pure torsional shear waves are generated by an apparatus which includes a stator element fixed to the borehole walls and a rotor element which is electrically driven to rapidly oscillate on the stator element to cause reaction forces transmitted through the borehole walls to the surrounding earth. Logitudinal shear waves are generated by an armature that is driven to rapidly oscillate along the axis of the borehole relative to a stator that is clamped to the borehole, to cause reaction forces transmitted to the surrounding earth. Pressure waves are generated by electrically driving pistons that press against opposite ends of a hydraulic reservoir that fills the borehole. High power is generated by energizing the elements at a power level that causes heating to over 150.degree. C. within one minute of operation, but energizing the elements for no more than about one minute.

  6. Rare earth element abundances in rocks and minerals from the Fiskenaesset Complex, West Greenland. [comparison with lunar anorthosites

    NASA Technical Reports Server (NTRS)

    Henderson, P.; Fishlock, S. J.; Laul, J. C.; Cooper, T. D.; Conard, R. L.; Boynton, W. V.; Schmitt, R. A.

    1976-01-01

    The paper reports activation-analysis determinations of rare-earth-element (REE) and other trace-element concentrations in selected rocks, plagioclase, and mafic separates from the Fiskenaesset Complex. The REE abundances are found to be very low and atypical in comparison with other terrestrial anorthosites. The plagioclases are shown to be characterized by a deficiency in heavy RE elements relative to light ones and a positive Eu anomaly, while the mafic separates are enriched in heavy rare earths and have no Eu anomaly, except in one sample. It is found that the bulk and trace-element abundances of the plagioclases are similar to those observed in some lunar anorthosites, but the degree of Eu anomaly is less in the plagioclases. The data are taken as confirmation of the idea that fractionation processes were involved in the origin of the Complex, and it is concluded that the Complex may have been produced from a magma generated by partial melting of a garnet-bearing source.

  7. Rare earth elements minimal harvest year variation facilitates robust geographical origin discrimination: The case of PDO "Fava Santorinis".

    PubMed

    Drivelos, Spiros A; Danezis, Georgios P; Haroutounian, Serkos A; Georgiou, Constantinos A

    2016-12-15

    This study examines the trace and rare earth elemental (REE) fingerprint variations of PDO (Protected Designation of Origin) "Fava Santorinis" over three consecutive harvesting years (2011-2013). Classification of samples in harvesting years was studied by performing discriminant analysis (DA), k nearest neighbours (κ-NN), partial least squares (PLS) analysis and probabilistic neural networks (PNN) using rare earth elements and trace metals determined using ICP-MS. DA performed better than κ-NN, producing 100% discrimination using trace elements and 79% using REEs. PLS was found to be superior to PNN, achieving 99% and 90% classification for trace and REEs, respectively, while PNN achieved 96% and 71% classification for trace and REEs, respectively. The information obtained using REEs did not enhance classification, indicating that REEs vary minimally per harvesting year, providing robust geographical origin discrimination. The results show that seasonal patterns can occur in the elemental composition of "Fava Santorinis", probably reflecting seasonality of climate. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. A Numerical Examination of the Long-Term Coherency of Meteoroid Streams in Near-Earth Orbit

    NASA Astrophysics Data System (ADS)

    Grazier, K. R.; Lipschutz, M. E.

    2000-05-01

    The statement that some small bodies in the Solar System--asteroids, comets, meteors (of cometary origin)--travel in co-orbital streams, would be accepted by planetary scientists without argument. After all, streams have been observed of fragments of at least one comet (Scotti and Melosh, 1993; Weaver et al., 1993), asteroids (Drummond, 1991; Rabinowitz et al., 1993; Binzel and Xu, 1993) and meteoroids of asteroidal origin, like Innisfree (Halliday et al., 1990; cf. Drummond, 1991). Whether members of a stream can be recognized from compositional studies of meteorites recovered on Earth and linked to a common source is more controversial since such linkage would imply variations in the Earth's sampling of extraterrestrial material that persist for tens of Myr. The dates of fall of H chondrites show that many - including Clusters in May, 1855-1895, September, 1812-1831 and Sept.-Oct., 1843-1992 -- apparently derive from specific meteoroids (Lipschutz et al., 1997). Contents of highly volatile elements in these 3 Clusters (selected by one criterion, fall circumstances), when analyzed using multivariate statistical techniques demonstrate that members of each Cluster (i.e. stream) are recognizable by a totally different characteristic criterion: a thermal history distinguishable from those of random H chondrite falls (cf. Lipschutz et al., 1997, for specific references). Antarctic H chondrites with terrestrial ages 50 Myr (Michlovich et al., 1995) also show this. Metallographic and thermoluminescence data for these H chondrites also reflect their thermal histories, and support the existence of such meteoroid streams (Sears et al., 1991; Benoit and Sears, 1993), but cosmogenic noble gas contents do not (Loeken et al., 1993; Schultz and Weber, 1996). Important unanswered orbital dynamic questions are how long a meteoroid stream should be recognizable and what dynamic conditions are implied by Clusters, whose members have cosmic ray exposure ages of some Myr. To begin to address these open issues, we simulate the trajectories of several near-Earth meteoroid streams--some with orbital elements corresponding to suspected streams, others randomly chosen. To integrate the trajectories as accurately as possible, we use an error-optimized modified 13th order Störmer integration scheme, capable of handling close planet/meteoroid approaches (Grazier et al., 1998). Using Drummond's (1979) d' criteria to determine stream membership and coherency as a function of time, we find that stream coherency beyond 100 Ky--certainly beyond 1 My--exists but is rare.

  9. The physics of the earth's core: An introduction

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Melchior, P.

    1986-01-01

    This book is a reference text providing information on physical topics of recent developments in internal geophysics. The text summarizes papers covering theoretical geophysics. Basic formulae, definitions and theorems are not explained in detail due to the limited space. The contents include applications to geodesy, geophysics, astronomy, astrophysics, geophysics and planetary physics. The formal contents include: The Earth's model; Thermodynamics; Hydrodynamics; Geomagnetism; Geophysical implications in the Earth's core.

  10. Empirically assessing the potential release of rare earth elements from black shale under simulated hydraulic fracturing conditions

    DOE PAGES

    Yang, Jon; Verba, Circe; Torres, Marta; ...

    2018-02-01

    Rare earth elements (REEs) are economically important to modern society and the rapid growth of technologies dependent on REEs has placed considerable economic pressure on their sourcing. This study addresses whether REEs could be released as a byproduct of natural gas extraction from a series of experiments that were designed to simulate hydraulic fracturing of black shale under various pressure (25 and 27.5 MPa) and temperature (50, 90, 130 °C) conditions. The dissolved REEs in the reacted fluids displayed no propensity for the REEs to be released from black shale under high pressure and temperature conditions, a result that ismore » consistent across the different types of fluids investigated. Overall, there was a net loss of REEs from the fluid. These changes in dissolved REEs were greatest at the moment the fluids first contacted the shale and before the high temperature and high pressure conditions were imposed, although the magnitude of these changes (10 -4 μg/g) were small compared to the magnitude of the total REE content present in the solid shale samples (10 2 μg/g). These results highlight the variability and complexity of hydraulic fracturing systems and indicate that REE may not serve as robust tracers for fracturing fluid-shale reactions. Additionally, the results suggest that significant quantities of REEs may not be byproducts of hydraulically fractured shales.« less

  11. Empirically assessing the potential release of rare earth elements from black shale under simulated hydraulic fracturing conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yang, Jon; Verba, Circe; Torres, Marta

    Rare earth elements (REEs) are economically important to modern society and the rapid growth of technologies dependent on REEs has placed considerable economic pressure on their sourcing. This study addresses whether REEs could be released as a byproduct of natural gas extraction from a series of experiments that were designed to simulate hydraulic fracturing of black shale under various pressure (25 and 27.5 MPa) and temperature (50, 90, 130 °C) conditions. The dissolved REEs in the reacted fluids displayed no propensity for the REEs to be released from black shale under high pressure and temperature conditions, a result that ismore » consistent across the different types of fluids investigated. Overall, there was a net loss of REEs from the fluid. These changes in dissolved REEs were greatest at the moment the fluids first contacted the shale and before the high temperature and high pressure conditions were imposed, although the magnitude of these changes (10 -4 μg/g) were small compared to the magnitude of the total REE content present in the solid shale samples (10 2 μg/g). These results highlight the variability and complexity of hydraulic fracturing systems and indicate that REE may not serve as robust tracers for fracturing fluid-shale reactions. Additionally, the results suggest that significant quantities of REEs may not be byproducts of hydraulically fractured shales.« less

  12. Using Multithreading for the Automatic Load Balancing of 2D Adaptive Finite Element Meshes

    NASA Technical Reports Server (NTRS)

    Heber, Gerd; Biswas, Rupak; Thulasiraman, Parimala; Gao, Guang R.; Bailey, David H. (Technical Monitor)

    1998-01-01

    In this paper, we present a multi-threaded approach for the automatic load balancing of adaptive finite element (FE) meshes. The platform of our choice is the EARTH multi-threaded system which offers sufficient capabilities to tackle this problem. We implement the question phase of FE applications on triangular meshes, and exploit the EARTH token mechanism to automatically balance the resulting irregular and highly nonuniform workload. We discuss the results of our experiments on EARTH-SP2, an implementation of EARTH on the IBM SP2, with different load balancing strategies that are built into the runtime system.

  13. Using Multi-threading for the Automatic Load Balancing of 2D Adaptive Finite Element Meshes

    NASA Technical Reports Server (NTRS)

    Heber, Gerd; Biswas, Rupak; Thulasiraman, Parimala; Gao, Guang R.; Saini, Subhash (Technical Monitor)

    1998-01-01

    In this paper, we present a multi-threaded approach for the automatic load balancing of adaptive finite element (FE) meshes The platform of our choice is the EARTH multi-threaded system which offers sufficient capabilities to tackle this problem. We implement the adaption phase of FE applications oil triangular meshes and exploit the EARTH token mechanism to automatically balance the resulting irregular and highly nonuniform workload. We discuss the results of our experiments oil EARTH-SP2, on implementation of EARTH on the IBM SP2 with different load balancing strategies that are built into the runtime system.

  14. Carbon footprint assessment of recycling technologies for rare earth elements: A case study of recycling yttrium and europium from phosphor.

    PubMed

    Hu, Allen H; Kuo, Chien-Hung; Huang, Lance H; Su, Chao-Chin

    2017-02-01

    Rare earth elements are key raw materials in high-technology industries. Mining activities and manufacturing processes of such industries have caused considerable environmental impacts, such as soil erosion, vegetation destruction, and various forms of pollution. Sustaining the long-term supply of rare earth elements is difficult because of the global shortage of rare earth resources. The diminishing supply of rare earth elements has attracted considerable concern because many industrialized countries regarded such elements as important strategic resources for economic growth. This study aims to explore the carbon footprints of yttrium and europium recovery techniques from phosphor. Two extraction recovery methods, namely, acid extraction and solvent extraction, were selected for the analysis and comparison of carbon footprints. The two following functional units were used: (1) the same phosphor amounts for specific Y and Eu recovery concentrations, and (2) the same phosphor amounts for extraction. For acid extraction method, two acidic solutions (H 2 SO 4 and HCl) were used at two different temperatures (60 and 90°C). For solvent extraction method, acid leaching was performed followed by ionic liquid extraction. Carbon footprints from acid and solvent extraction methods were estimated to be 10.1 and 10.6kgCO 2 eq, respectively. Comparison of the carbon emissions of the two extraction methods shows that the solvent extraction method has significantly higher extraction efficiency, even though acid extraction method has a lower carbon footprint. These results may be used to develop strategies for life cycle management of rare earth resources to realize sustainable usage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Distribution and Translocation of 141Ce (III) in Horseradish

    PubMed Central

    Guo, Xiaoshan; Zhou, Qing; Lu, Tianhong; Fang, Min; Huang, Xiaohua

    2007-01-01

    Background and Aims Rare earth elements (REEs) are used in agriculture and a large amount of them contaminate the environment and enter foods. The distribution and translocation of 141Ce (III) in horseradish was investigated in order to help understand the biochemical behaviour and toxic mechanism of REEs in plants. Method The distribution and translocation of 141Ce (III) in horseradish were investigated using autoradiography, liquid scintillation counting (LSC) and electron microscopic autoradiography (EMARG) techniques. The contents of 141Ce (III) and nutrient elements were analysed using an inductively coupled plasma-atomic emission spectrometer (ICP-AES). Results The results from autoradiography and LSC indicated that 141Ce (III) could be absorbed by horseradish and transferred from the leaf to the leaf-stalk and then to the root. The content of 141Ce (III) in different parts of horseradish was as follows: root > leaf-stalk > leaf. The uptake rates of 141Ce (III) in horseradish changed with the different organs and time. The content of 141Ce (III) in developing leaves was greater than that in mature leaves. The results from EMARG indicated that 141Ce (III) could penetrate through the cell membrane and enter the mesophyll cells, being present in both extra- and intra-cellular deposits. The contents of macronutrients in horseradish were decreased by 141Ce (III) treatment. Conclusions 141Ce (III) can be absorbed and transferred between organs of horseradish with time, and the distribution was found to be different at different growth stages. 141Ce (III) can enter the mesophyll cells via apoplast and symplast channels or via plasmodesmata. 141Ce (III) can disturb the metabolism of macronutrients in horseradish. PMID:17921527

  16. Insights into the mantle geochemistry of scandium from a meta-analysis of garnet data

    NASA Astrophysics Data System (ADS)

    Chassé, Mathieu; Griffin, William L.; Alard, Olivier; O'Reilly, Suzanne Y.; Calas, Georges

    2018-06-01

    The meta-analysis of about 13,000 analyses of scandium content in garnet grains shows that, below the spinel-garnet transition, this phase carries about three-quarters of the Sc budget of the mantle, indicating its control on Sc mobility. The Sc content of garnets in mafic rocks is low, due to a dilution effect resulting from their high modal content in garnet. Garnets from ultramafic rocks exhibit a wider range of Sc concentrations. We assess the relative influence of thermobarometry, crystal chemistry and fluid-related events on the distribution of Sc in garnet from such rocks to improve the tracking of geochemical processes in the mantle. Pressure and temperature of equilibration in the mantle are second-order factors influencing the Sc content of garnet, while crystal chemistry, in particular Cr/Cr+Al and Ca/Ca+Mg, is the main parameter controlling the compatibility of Sc. Scandium is incorporated in both X and Y sites of Cr-Ca-rich garnets, resulting in a behaviour intermediate between rare-earth elements, incorporated in the X site, and trivalent transition elements, occupying the Y site. This affinity for both sites results in a mild compatibility of Sc in the garnet stability field of the mantle; hence Sc concentration in garnet increases with melt extraction and can be reduced by silicate-melt metasomatism. In contrast, metasomatism by volatile-rich fluids increases the Sc concentration in garnet. The control of garnet on the compatibility of Sc in deep lithospheric rocks demonstrates the potential of using Sc to track the conditions of formation of magmas and their residual rocks, as well as the origin and nature of metasomatic fluids.

  17. Geology, geochronology, and geochemistry of basaltic flows of the Cat Hills, Cat Mesa, Wind Mesa, Cerro Verde, and Mesita Negra, central New Mexico

    USGS Publications Warehouse

    Maldonado, F.; Budahn, J.R.; Peters, L.; Unruh, D.M.

    2006-01-01

    The geochronology, geochemistry, and isotopic compositions of basaltic flows erupted from the Cat Hills, Cat Mesa, Wind Mesa, Cerro Verde, and Mesita Negra volcanic centres in central New Mexico indicate that each of these lavas had unique origins and that the predominant mantle involved in their production was an ocean-island basalt type. The basalts from Cat Hills (0.11 Ma) and Cat Mesa (3.0 Ma) are similar in major and trace element composition, but differences in MgO contents and Pb isotopic values are attributed to a small involvement of a lower crustal component in the genesis of the Cat Mesa rocks. The Cerro Verde rock is comparable in age (0.32 Ma) to the Cat Hills lavas, but it is more radiogenic in Sr and Nd, has higher MgO contents, and has a lower La/Yb ratio. This composition is explained by the melting of an enriched mantle source, but the involvement of another crustal component cannot be disregarded. The Wind Mesa rock is characterized by similar age (4.01 Ma) and MgO contents, but it has enriched rare-earth element contents compared with the Cat Mesa samples. These are attributed to a difference in the degree of partial melting of the Cat Mesa source. The Mesita Negra rock (8.11 Ma) has distinctive geochemical and isotopic compositions that suggest a different enriched mantle and that large amounts of a crustal component were involved in generating this magma. These data imply a temporal shift in magma source regions and crustal involvement, and have been previously proposed for Rio Grande rift lavas. ?? 2006 NRC Canada.

  18. Element Mass Balance in Soils : the Mount Cameroon Case

    NASA Astrophysics Data System (ADS)

    Dia, A.; Chauvel, C.; Bulourde, M.

    2002-12-01

    Mount Cameroon is an active volcano located in Central Africa. Its location in a tropical climate area leads to abundant vegetation and intense weathering conditions that favor rapid alteration. Soils develop rapidly on the flanks of the volcano. We measured major and trace element contents as well as Pb, Nd and Sr isotopic compositions in three soil sections developed on basaltic tuffaceous units. Each section comprises 2-3 units, the upper portions of which are altered to soil (Andepts). The starting material is pyroclastic alkali basalt characterized by marked enrichment in trace elements. To determine the element flux during soil formation, two corrections have to be performed: (1) the parental rock composition has to be determined and (2) addition of Saharan dust as evidenced by [1] has to be corrected for. The starting rock composition is constrained using the Al/Fe vs C.I.A. relationship and the uppermost part of each soil is corrected for its eolian dust contribution (*10%). The budget for each element can then be estimated in the soils. Calculations are performed relative to an `immobile' element whose concentration is assumed to be unchanged during soil formation. We chose Th as a reference because its behavior during magmatic processes is similar to those of U, Rb, Ba, Cs and K which are known to be mobile during weathering processes. Results of the element budget calculations show that: alkali and alkaline earth elements are leached out of the soils (~ 50%). Silica losses (~ 30%) are also clear in all samples. For the other elements, systematic differences exist between bottom and top parts of each soil. The uppermost levels display significant changes Ni, U, Pb, P, Ni and Co contents. These mobilities are most probably related to hydrolysis of primary magmatic minerals triggered by the biological activity. Since the three studied sections correspond to the superposition of several soils where new tephra cover an older soil to be the basis of the formation of a new and younger soil, the element mass balance depends both on the paleoclimate conditions that prevailed during exposure to surface conditions, and on the duration of the exposure to air before the soil was covered by a new eruption. [1] Chauvel C., Dia A and Bulourde M., GCA, Vol 66, 14A, p A132, 2002.

  19. Vocabulary and Content Learning in Grade 9 Earth Science: Effects of Vocabulary Preteaching, Rational Cloze Task, and Reading Comprehension Task

    ERIC Educational Resources Information Center

    Lee, Siok H.

    2010-01-01

    This study examines strategies for supporting vocabulary and content learning in 5 grade 9 Earth Science classes that are part of a SDAIE program (Specially Designed Academic Instruction in English) in an urban California high school. Students received vocabulary and content instruction during a unit on Earthquakes. One group of students performed…

  20. Rock-forming and rare elements in lunar surface material from the Sea of Tranquillity and the Ocean of Storms

    NASA Technical Reports Server (NTRS)

    Shevaleyevskiy, I. D.; Chupakhin, M. S.

    1974-01-01

    Methodological and analytical capabilities associated with spark mass spectrometry and X-ray spectroscopy are presented for the determination of the elemental composition of samples of lunar regolith returned to the earth by Apollo 11 and Apollo 12. Using X-ray spectroscopy, the main constituents of samples of lunar surface material were determined, and using mass spectrometry -- the main admixtures. The principal difference of Apollo 11 samples from Apollo 12 samples was found for elements contained in microconcentrations. This is especially true of rare earth elements.

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