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Sample records for serpentine group minerals

  1. Bioleaching of serpentine group mineral by fungus Talaromyces flavus: application for mineral carbonation

    Science.gov (United States)

    Li, Z.; Lianwen, L.; Zhao, L.; Teng, H.

    2011-12-01

    Many studies of serpentine group mineral dissolution for mineral carbonation have been published in recent years. However, most of them focus mainly on either physical and chemical processes or on bacterial function, rather than fungal involvement in the bioleaching of serpentine group mineral. Due to the excessive costs of the magnesium dissolution process, finding a lower energy consumption method will be meaningful. A fungal strain Talaromyces flavus was isolated from serpentinic rock of Donghai (China). No study of its bioleaching ability is currently available. It is thus of great significance to explore the impact of T. flavus on the dissolution of serpentine group mineral. Serpentine rock-inhabiting fungi belonging to Acremonium, Alternaria, Aspergillus, Botryotinia, Cladosporium, Clavicipitaceae, Cosmospora, Fusarium, Monascus, Paecilomyces, Penicillium, Talaromyces, Trichoderma were isolated. These strains were chosen on the basis of resistance to magnesium and nickel characterized in terms of minimum inhibiting concentration (MIC). Specifically, the strain Talaromyces flavus has a high tolerance to both magnesium (1 mol/L) and nickel (10 mM/L), and we examine its bioleaching ability on serpentine group mineral. Contact and separation experiments (cut-off 8 000-14 000 Da), as well as three control experiments, were set up for 30 days. At least three repeated tests were performed for each individual experiment. The results of our experiments demonstrate that the bioleaching ability of T. flavus towards serpentine group mineral is evident. 39.39 wt% of magnesium was extracted from lizardite during the bioleaching period in the contact experiment, which showed a dissolution rate at about a constant 0.126 mM/d before reaching equilibrium in 13 days. The amount of solubilized Mg from chrysotile and antigorite were respectively 37.79 wt% and 29.78 wt% in the contact experiment. These results make clear the influence of mineral structure on mineral bioleaching

  2. Platinum-Group Minerals in Chromitites of the Niquelândia Layered Intrusion (Central Goias, Brazil: Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering

    Directory of Open Access Journals (Sweden)

    Nelson Angeli

    2012-10-01

    Full Text Available A variety of platinum-group-minerals (PGM have been found to occur associated with the chromitite and dunite layers in the Niquelândia igneous complex. Two genetically distinct populations of PGM have been identified corresponding to phases crystallized at high temperatures (primary, and others formed or modified during post-magmatic serpentinization and lateritic weathering (secondary. Primary PGM have been found in moderately serpentinized chromitite and dunite, usually included in fresh chromite grains or partially oxidized interstitial sulfides. Due to topographically controlled lateritic weathering, the silicate rocks are totally transformed to a smectite-kaolinite-garnierite-amorphous silica assemblage, while the chromite is changed into a massive aggregate of a spinel phase having low-Mg and a low Fe3+/Fe2+ ratio, intimately associated with Ti-minerals, amorphous Fe-hydroxides, goethite, hematite and magnetite. The PGM in part survive alteration, and in part are corroded as a result of deep chemical weathering. Laurite is altered to Ru-oxides or re-crystallizes together with secondary Mg-ilmenite. Other PGM, especially the Pt-Fe alloys, re-precipitate within the altered chromite together with kaolinite and Fe-hydroxides. Textural evidence suggests that re-deposition of secondary PGM took place during chromite alteration, controlled by variation of the redox conditions on a microscopic scale.

  3. Moessbauer Study of Serpentine Minerals in the Ultramafic Body of Tehuitzingo, Southern Mexico

    International Nuclear Information System (INIS)

    Gonzalez-Mancera, G.; Ortega-Gutierrez, F.; Nava, N. E.; Arriola, H. S.

    2003-01-01

    Serpentine 'polymorph' minerals (chrysotile, lizardite, and antigorite) are hydrous Mg-Fe silicates that commonly form serpentine rock (serpentinite) by hydration of olivine-pyroxene peridotites from the mantle of the Earth. During the complex geologic history of orogenic belts, the redox and hydration state of the mantle changes, and olivine and pyroxenes are replaced by serpentine group minerals during tectonic deformation and uplift. Unfortunately, modern microanalysis of minerals by electron probe does not distinguish the oxidation state of iron, and it has to be assumed or estimated by precise methods, such as Moessbauer spectrometry. The studied samples were collected in the Xayacatlan Formation of the Tehuitzingo area, State of Puebla, within the Paleozoic Acatlan Complex. The original mantle peridotite was completely converted to serpentinite, with secondary crystallization of Fe-Mg oxides, calcsilicates, and carbonates. The three serpentine 'polymorphs' were identified in the studied samples, although with a clear predominance of the high-temperature member antigorite, which was preliminary determined by optical petrography, X-ray diffraction, electron probe, and scanning electron microscopy. Microprobe total iron content in most specimens was +3 substitution at the tetrahedral site may also occur according to some Moessbauer studies. This paper studied the iron valence state and its position in serpentine minerals of the Tehuitzingo ultramafic body using Moessbauer techniques. The analyses in most samples detected one doublet, compatible with Fe +2 in octahedral coordination, but only two specimens displayed two doublets corresponding to Fe +2 and Fe +3 in octahedral coordination. Doublets corresponding to Fe +3 in tetrahedral sites were not found. The parameters obtained for all the Fe +2 doublets are similar (QS=2.76±0.08 mm/sec, and IS=1.12±0.01), whereas the ratio Fe +3 /Fe +2 (0-0.34) has a strong tendency for iron to be in a divalent state. This

  4. Application of k0-based NAA for multielement determination in serpentines and associated minerals

    International Nuclear Information System (INIS)

    Nagendra Kumar, P.V.; S.V. University, Tirupati; Suresh Kumar, N.; King Fahad Specialist Hospital, Dammam; Acharya, R.; Krishna Reddy, L.; Reddy, A.V.R.

    2014-01-01

    The k 0 -based neutron activation analysis method was applied for multielement determination in black and yellow serpentines along with two associated minerals namely altered and unaltered dolomites and intrusive rock dolerite, obtained from the asbestos mines of Cuddapah basin, Andhra Pradesh, India. Concentrations of 20 elements were determined and they were used to predict the process of formation of fibrous chrysotile asbestos. Majority of elements as well as REEs reveal the contribution of elements from both dolerite and dolomite during the process of contact metamorphism in forming the mineral serpentine. (author)

  5. Using MicroFTIR to Map Mineral Distributions in Serpentinizing Systems

    Science.gov (United States)

    Johnson, A.; Kubo, M. D.; Cardace, D.

    2016-12-01

    Serpentinization, the water-rock reaction forming serpentine mineral assemblages from ultramafic precursors, can co-occur with the production of hydrogen, methane, and diverse organic compounds (McCollom and Seewald, 2013), evolving water appropriate for carbonate precipitation, including in ophiolite groundwater flow systems and travertine-producing seeps/springs. Serpentinization is regarded as a geologic process important to the sustainability of the deep biosphere (Schrenk et al., 2013) and the origin of life (Schulte et al., 2006). In this study, we manually polished wafers of ultramafic rocks/associated minerals (serpentinite, peridotite, pyroxenite, dunite; olivine, diopside, serpentine, magnetite), and travertine/constituent minerals (carbonate crusts; calcite, dolomite), and observed mineral boundaries and interfaces using µFTIR analysis in reflection mode. We used a Thermo Nicolet iS50 FTIR spectrometer coupled with a Continuum IR microscope to map minerals/boundaries. We identify, confirm, and document FTIR wavenumber regions linked to serpentinite- and travertine-associated minerals by referencing IR spectra (RRUFF) and aligning with x-ray diffraction. The ultramafic and carbonate samples are from the following field localities: McLaughlin Natural Reserve - a UC research reserve, Lower Lake, CA; Zambales, PH; Ontario, CA; Yellow Dog, MI; Taskesti, TK; Twin Sisters Range, WA; Sharon, MA; Klamath Mountains, CA; Dun Mountain, NZ; and Sussex County, NJ. Our goals are to provide comprehensive µFTIR characterization of mineral profiles important in serpentinites and related rocks, and evaluate the resolving power of µFTIR for the detection of mineral-encapsulated, residual organic compounds from biological activity. We report on µFTIR data for naturally occurring ultramafics and travertines and also estimate the limit of detection for cell membrane components in mineral matrices, impregnating increasing mass proportions of xanthan gum in a peridotite sand

  6. Chromite and other mineral deposits in serpentine rocks of the Piedmont Upland, Maryland, Pennsylvania, and Delaware

    Science.gov (United States)

    Pearre, Nancy C.; Heyl, Allen V.

    1960-01-01

    The Piedmont Upland in Maryland, Pennsylvania, and Delaware is about 160 miles long and at the most 50 miles wide. Rocks that underlie the province are the Baltimore gneiss of Precambrian age and quartzite, gneiss, schist, marble, phyllite, and greenstone, which make up the Glenarm series of early Paleozoic (?) age. These are intruded by granitic, gabbroic, and ultramaflc igneous rocks. Most of the ultramaflc rocks, originally peridotite, pyroxenite, and dunite, have been partly or completely altered to serpentine and talc; they are all designated by the general term serpentine. The bodies of serpentine are commonly elongate and conformable with the enclosing rocks. Many have been extensively quarried for building, decorative, and crushed stone. In addition, chromite, titaniferous magnetite, rutile, talc and soapstone, amphibole asbestos, magnesite, sodium- rich feldspar (commercially known as soda spar), and corundum have been mined or prospected for in the serpentine. Both high-grade massive chromite and lower grade disseminated chromite occur in very irregular and unpredictable form in the serpentine, and placer deposits of chromite are in and near streams that drain areas underlain by serpentine. A group of unusual minerals, among them kammererite, are typical associates of high-grade massive chromite but are rare in lower grade deposits. Chromite was first discovered in the United States at Bare Hills, Md., around 1810. Between 1820 and 1850, additional deposits were discovered and mined in Maryland and Pennsylvania, including the largest deposit of massive chromite ever found in the United States the Wood deposit, in the State Line district. A second period of extensive chromite mining came during the late 1860's and early 1870's. Production figures are incomplete and conflicting. Estimates from the available data indicate that the aggregate production from 27 of 40 known mines before 1900 totaled between 250,000 and 280,000 tons of lode-chromite ore

  7. Mineral textures in Serpentine-hosted Alkaline Springs from the Oman ophiolite

    Science.gov (United States)

    Giampouras, Manolis; Garcia-Ruiz, Juan Manuel; Bach, Wolfgang; Garrido, Carlos J.; Los, Karin; Fussmann, Dario; Monien, Monien

    2017-04-01

    Meteoric water infiltration in ultramafic rocks leads to serpentinization and the formation of subaerial, low temperature, hydrothermal alkaline springs. Here, we present a detailed investigation of the mineral precipitation mechanisms and textural features of mineral precipitates, along as the geochemical and hydrological characterization, of two alkaline spring systems in the Semail ophiolite (Nasif and Khafifah sites, Wadi Tayin massif). The main aim of the study is to provide new insights into mineral and textural variations in active, on-land, alkaline vents of the Oman ophiolite. Discharge of circulating fluids forms small-scale, localized hydrological catchments consisting in unevenly interconnected ponds. Three different types of waters can be distinguished within the pond systems: i) Mg-type; alkaline (7.9 11.6), Ca-OH-rich waters; and iii) Mix-type waters arising from the mixing of Mg-type and Ca-type waters (9.6 ponds were carried out by X-ray diffraction (XRD), Raman spectroscopy and field-emission scanning electron microscopy coupled to dispersive energy spectroscopy (FE-SEM-EDS). Aragonite and calcite are the dominant minerals (95 vol.%) of the total mineralogical index in all sites. Mg-type waters host hydrated magnesium carbonates (nesquehonite) and magnesium hydroxycarbonate hydrates (artinite) due to evaporation. Brucite, hydromagnesite and dypingite presence in Mix-type waters is spatially controlled by the hydrology of the system and is localized around mixing zones between Ca-type with Mg-type waters. Residence time of discharging waters in the ponds before mixing has an impact on fluid chemistry as it influences the equilibration time with the atmosphere. Acicular aragonite is the main textural type in hyper-alkaline Ca-type waters, acting as a substratum for the growth of calcite and brucite crystals. Low crystallinity, dumbbell shaped and double pyramid aragonite dominates in Mix-type water precipitates. Rate of supersaturation is essential

  8. H2-rich fluids from serpentinization: Geochemical and biotic implications

    OpenAIRE

    Sleep, N. H.; Meibom, A.; Fridriksson, Th.; Coleman, R. G.; Bird, D. K.

    2004-01-01

    Metamorphic hydration and oxidation of ultramafic rocks produces serpentinites, composed of serpentine group minerals and varying amounts of brucite, magnetite, and/or FeNi alloys. These minerals buffer metamorphic fluids to extremely reducing conditions that are capable of producing hydrogen gas. Awaruite, FeNi3, forms early in this process when the serpentinite minerals are Fe-rich. Olivine with the current mantle Fe/Mg ratio was oxidized during serpentinization after the Moon-forming impac...

  9. Sliding friction and wear behaviors of surface-coated natural serpentine mineral powders as lubricant additive

    International Nuclear Information System (INIS)

    Zhang Baosen; Xu Yi; Gao Fei; Shi Peijing; Xu Binshi; Wu Yixiong

    2011-01-01

    This work aims to investigate the friction and wear properties of surface-coated natural serpentine powders (SP) suspended in diesel engine oil using an Optimal SRV oscillating friction and wear tester. The worn surface was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). Results indicated that the additives can improve the wear resistance and decrease friction coefficient of carbon steel friction couples. The 0.5 wt% content of serpentine powders is found most efficient in reducing friction and wear at the load of 50 N. The SEM and XPS analysis results demonstrate that a tribofilm forms on the worn surface, which is responsible for the decrease in friction and wear, mainly with iron oxides, silicon oxides, graphite and organic compounds.

  10. Platinum-group element mineralization

    International Nuclear Information System (INIS)

    Gruenewaldt, G.

    1985-01-01

    The purpose of this investigation is to determine the geological processes responsible for the abnormal enrichment of the platinum-group elements (PGE) in the mineralized layers of the Bushveld Complex. Questions asked are: what processes caused enrichment of the Bushveld magma in the PGE ; by what processes were these PGE concentrated in the mineralized layers ; was contamination of the Bushveld magma from external sources important in the formation of the PGE enriched layers ; what are the effects of fractional crystallization on the PGE ratios

  11. Grouping Minerals by Their Formulas

    Science.gov (United States)

    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.…

  12. SIMULTANEOUS MECHANICAL AND HEAT ACTIVATION: A NEW ROUTE TO ENHANCE SERPENTINE CARBONATION REACTIVITY AND LOWER CO2 MINERAL SEQUESTRATION PROCESS COST

    Energy Technology Data Exchange (ETDEWEB)

    M.J. McKelvy; J. Diefenbacher; R. Nunez; R.W. Carpenter; A.V.G. Chizmeshya

    2005-01-01

    Coal can support a large fraction of global energy demands for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Unlike other candidate technologies, which propose long-term storage (e.g., ocean and geological sequestration), mineral sequestration permanently disposes of CO{sub 2} as geologically stable mineral carbonates. Only benign, naturally occurring materials are formed, eliminating long-term storage and liability issues. Serpentine carbonation is a leading mineral sequestration process candidate, which offers large scale, permanent sequestration. Deposits exceed those needed to carbonate all the CO{sub 2} that could be generated from global coal reserves, and mining and milling costs are reasonable ({approx}$4 to $5/ton). Carbonation is exothermic, providing exciting low-cost process potential. The remaining goal is to develop an economically viable process. An essential step in this development is increasing the carbonation reaction rate and degree of completion, without substantially impacting other process costs. Recently, the Albany Research Center (ARC) has accelerated serpentine carbonation, which occurs naturally over geological time, to near completion in less than an hour. While reaction rates for natural serpentine have been found to be too slow for practical application, both heat and mechanical (attrition grinding) pretreatment were found to substantially enhance carbonation reactivity. Unfortunately, these processes are too energy intensive to be cost-effective in their present form. In this project we explored the potential that utilizing power plant waste heat (e.g., available up to {approx}200-250 C) during mechanical activation (i.e., thermomechanical activation) offers to enhance serpentine mineral carbonation, while reducing pretreatment energy consumption and process cost. This project was carried out in collaboration with the Albany Research Center (ARC) to maximize the insight into the

  13. Effect of Hydrochemistry on Mineral Precipitation and Textural Diversity in Serpentinization-driven Alkaline Environments; Insights from Thermal Springs in the Oman Ophiolite.

    Science.gov (United States)

    Bach, W.; Giampouras, M.; Garcia-Ruiz, J. M.; Garrido, C. J.; Los, C.; Fussmann, D.; Monien, P.

    2017-12-01

    shift towards more alkaline conditions due to occasional mixing. This study demonstrates that water mixing, atmospheric CO2 up-take, and evaporation are the main drivers of precipitation and textural differentiation of minerals occurring in serpentinization-driven alkaline environments.

  14. Evolution of borate minerals from contact metamorphic to hydrothermal stages: Ludwigite-group minerals and szaibélyite from the Vysoká - Zlatno skarn, Slovakia

    Science.gov (United States)

    Bilohuščin, Vladimír; Uher, Pavel; Koděra, Peter; Milovská, Stanislava; Mikuš, Tomáš; Bačík, Peter

    2017-09-01

    Borate minerals of the ludwigite group (LGM) and szaibélyite in association with hydroxylclinohumite, clinochlore, a serpentine mineral, magnesian magnetite, spinel, magnesite, dolomite and sulphide minerals, occur in a magnesian exoskarn in the R-20 borehole located in the Vysoká - Zlatno Cu-Au porphyry-skarn deposit, located within the Štiavnica Neogene stratovolcano, Western Carpathians, central Slovakia. The skarn is developed along the contact of Miocene granodiorite to quartz-diorite porphyry and a Middle-Upper Triassic dolomite-shale-psammite-anhydrite sedimentary sequence. The boron minerals were investigated by electron probe micro-analyser (EPMA) and micro-Raman techniques. The source of boron could have been from the granodiorite/quartz diorite intrusion; however some supply of B from adjacent evaporite-bearing sediments is also possible. Based on textural and compositional data, the minerals originated during two stages. (1) An early high-temperature, contact-metamorphic and metasomatic stage comprises coarse-crystalline aggregate of LGM (types 1 to 3) in association with hydroxylclinohumite, magnetite, and rarely spinel inclusions in LGM. Compositional variations of LGM show a crystallization sequence from early azoproite [≤17 wt% TiO2; 0.40 atoms pre formula unit (apfu) Ti, which correspond to ≤79 mol% of the Mg2(Mg0.5Ti0.5)O2(BO3) end-member], Ti-Al-rich members of LGM, "aluminoludwigite "[≤14 wt% Al2O3; ≤0.53 apfu, ≤53 mol% of Mg2AlO2(BO3) end-member] and Al-rich ludwigite in the central zone of crystals, to Ti-Al-poor ludwigite in outer parts of crystals. (2) Minerals of the late retrograde serpentinization and hydrothermal stage form irregular veinlets and aggregates, including partial alteration of hydroxylclinohumite to the serpentine-group mineral and clinochlore, replacement of LGM by szaibélyite, formation of the latest generation of Fe-rich, Ti-Al poor ludwigite in veinlets (type 4), and precipitation of dolomite, magnesite and

  15. Experimental Study of Serpentinization Reactions

    Science.gov (United States)

    Cohen, B. A.; Brearley, A. J.; Ganguly, J.; Liermann, H.-P.; Keil, K.

    2004-01-01

    Current carbonaceous chondrite parent-body thermal models [1-3] produce scenarios that are inconsistent with constraints on aqueous alteration conditions based on meteorite mineralogical evidence, such as phase stability relationships within the meteorite matrix minerals [4] and isotope equilibration arguments [5, 6]. This discrepancy arises principally because of the thermal runaway effect produced by silicate hydration reactions (here loosely called serpentinization, as the principal products are serpentine minerals), which are so exothermic as to produce more than enough heat to melt more ice and provide a self-sustaining chain reaction. One possible way to dissipate the heat of reaction is to use a very small parent body [e.g., 2] or possibly a rubble pile model. Another possibility is to release this heat more slowly, which depends on the alteration reaction path and kinetics.

  16. Numerical quantification of habitability in serpentinizing systems

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    Som, S.; Alperin, M. J.; Hoehler, T. M.

    2012-12-01

    The likely presence of liquid water in contact with olivine-bearing rocks on Mars, the detection of serpentine minerals and of methane emissions possibly consistent with serpentinization, and the observation of serpentine-associated methane-cycling communities on Earth have all led to excitement over the potential of such systems to host life on Mars, even into the present day. However, the habitability of subsurface serpentinizing systems on Mars does not necessarily follow from these qualitative observations. In particular, while the production of H2 during serpentinization could provide methanogens with a needed substrate, the alkaline conditions and corresponding potential for carbon limitation that arise in concert are negatives against which H2 supply must be balanced. We considered this balance via a coupled geochemical-bioenergetic model that weighs the outputs of serpentinization against the metabolic requirements of methanogenesis, in an energetic frame of reference. Serpentinization is modeled using the "Geochemist's Workbench" (GWB) whereby ultramafic harzburgite rocks are reacted with oxygen and sulfate depleted seawater. Reaction kinetics are not explicitly considered, but comparable effects of partial reaction are approximated by assuming post-reaction dilution of equilibrated fluids. The output of GWB serves as the input to the bioenergetic model, which calculates methanogenic energy yields based on spherically-symmetrical diffusion of substrates to a cell followed by reaction at the diffusion-limited rate. Membrane selectivity for substrate transport is explicitly considered. Results will be report updates for two scenarios: (i) High temperature serpentinization followed by cooling and transport of equilibrated fluid to a lower temperature regime accessible to biology; (ii) Serpentinization within the biologically-tolerated range of temperatures. Such coupled models demonstrate that environmental variability with respect to both water-rock reaction

  17. Raman spectroscopy of garnet-group minerals

    Science.gov (United States)

    Mingsheng, P.; Mao, Ho-kwang; Dien, L.; Chao, E.C.T.

    1994-01-01

    The Raman spectra of the natural end members of the garnet-group minerals, which include pyrope, almandine and spessarite of Fe-Al garnet series and grossularite, andradite and uvarovite of Ca-Fe garnet series, have been studied. Measured Raman spectra of these minerals are reasonably and qualitatively assigned to the internal modes, translational and rotatory modes of SiO4 tetrahedra, as well as the translational motion of bivalent cations in the X site. The stretch and rotatory Alg modes for the Fe-Al garnet series show obvious Raman shifts as compared with those for the Ca-Fe garnet series, owing to the cations residing in the X site connected with SiO4 tetrahedra by sharing the two edges. The Raman shifts of all members within either of the series are attributed mainly to the properties of cations in the X site for the Fe-Al garnet series and in the Y site for the Ca-Fe garnet series. ?? 1994 Institute of Geochemistry, Chinese Academy of Sciences.

  18. Change in Frictional Behavior during Olivine Serpentinization

    Science.gov (United States)

    Xing, T.; Zhu, W.; French, M. E.; Belzer, B.

    2017-12-01

    Hydration of mantle peridotites (serpentinization) is pervasive at plate boundaries. It is widely accepted that serpentinization is intrinsically linked to hydromechanical processes within the sub-seafloor, where the interplay between cracking, fluid supply and chemical reactions is responsible for a spectrum of fault slip, from earthquake swarms at the transform faults, to slow slip events at the subduction zone. Previous studies demonstrate that serpentine minerals can either promote slip or creep depend on many factors that include sliding velocity, temperature, pressure, interstitial fluids, etc. One missing link from the experimental investigation of serpentine to observations of tectonic faults is the extent of alteration necessary for changing the frictional behaviors. We quantify changes in frictional behavior due to serpentinization by conducting experiments after in-situ serpentinization of olivine gouge. In the sample configuration a layer of powder is sandwiched between porous sandstone blocks with 35° saw-cut surface. The starting material of fine-grained (63 120 µm) olivine powder is reacted with deionized water for 72 hours at 150°C before loading starts. Under the conventional triaxial configuration, the sample is stressed until sliding occurs within the gouge. A series of velocity-steps is then performed to measure the response of friction coefficient to variations of sliding velocity from which the rate-and-state parameters are deduced. For comparison, we measured the frictional behavior of unaltered olivine and pure serpentine gouges.Our results confirm that serpentinization causes reduced frictional strength and velocity weakening. In unaltered olivine gouge, an increase in frictional resistance with increasing sliding velocity is observed, whereas the serpentinized olivine and serpentine gouges favor velocity weakening behaviors at the same conditions. Furthermore, we observed that high pore pressures cause velocity weakening in olivine but

  19. Mineralizing Filamentous Bacteria from the Prony Bay Hydrothermal Field Give New Insights into the Functioning of Serpentinization-Based Subseafloor Ecosystems.

    Science.gov (United States)

    Pisapia, Céline; Gérard, Emmanuelle; Gérard, Martine; Lecourt, Léna; Lang, Susan Q; Pelletier, Bernard; Payri, Claude E; Monnin, Christophe; Guentas, Linda; Postec, Anne; Quéméneur, Marianne; Erauso, Gaël; Ménez, Bénédicte

    2017-01-01

    Despite their potential importance as analogs of primitive microbial metabolisms, the knowledge of the structure and functioning of the deep ecosystems associated with serpentinizing environments is hampered by the lack of accessibility to relevant systems. These hyperalkaline environments are depleted in dissolved inorganic carbon (DIC), making the carbon sources and assimilation pathways in the associated ecosystems highly enigmatic. The Prony Bay Hydrothermal Field (PHF) is an active serpentinization site where, similar to Lost City (Mid-Atlantic Ridge), high-pH fluids rich in H 2 and CH 4 are discharged from carbonate chimneys at the seafloor, but in a shallower lagoonal environment. This study aimed to characterize the subsurface microbial ecology of this environment by focusing on the earliest stages of chimney construction, dominated by the discharge of hydrothermal fluids of subseafloor origin. By jointly examining the mineralogy and the microbial diversity of the conduits of juvenile edifices at the micrometric scale, we find a central role of uncultivated bacteria belonging to the Firmicutes in the ecology of the PHF. These bacteria, along with members of the phyla Acetothermia and Omnitrophica , are identified as the first chimneys inhabitants before archaeal Methanosarcinales . They are involved in the construction and early consolidation of the carbonate structures via organomineralization processes. Their predominance in the most juvenile and nascent hydrothermal chimneys, and their affiliation with environmental subsurface microorganisms, indicate that they are likely discharged with hydrothermal fluids from the subseafloor. They may thus be representative of endolithic serpentinization-based ecosystems, in an environment where DIC is limited. In contrast, heterotrophic and fermentative microorganisms may consume organic compounds from the abiotic by-products of serpentinization processes and/or from life in the deeper subsurface. We thus propose

  20. H2-rich fluids from serpentinization: geochemical and biotic implications.

    Science.gov (United States)

    Sleep, N H; Meibom, A; Fridriksson, Th; Coleman, R G; Bird, D K

    2004-08-31

    Metamorphic hydration and oxidation of ultramafic rocks produces serpentinites, composed of serpentine group minerals and varying amounts of brucite, magnetite, and/or FeNi alloys. These minerals buffer metamorphic fluids to extremely reducing conditions that are capable of producing hydrogen gas. Awaruite, FeNi3, forms early in this process when the serpentinite minerals are Fe-rich. Olivine with the current mantle Fe/Mg ratio was oxidized during serpentinization after the Moon-forming impact. This process formed some of the ferric iron in the Earth's mantle. For the rest of Earth's history, serpentinites covered only a small fraction of the Earth's surface but were an important prebiotic and biotic environment. Extant methanogens react H2 with CO2 to form methane. This is a likely habitable environment on large silicate planets. The catalytic properties of FeNi3 allow complex organic compounds to form within serpentinite and, when mixed with atmospherically produced complex organic matter and waters that circulated through basalts, constitutes an attractive prebiotic substrate. Conversely, inorganic catalysis of methane by FeNi3 competes with nascent and extant life. Copyright 2004 The National Academy of Sciencs of the USA

  1. Serpentinization processes: Influence of silica

    Science.gov (United States)

    Huang, R.; Sun, W.; Ding, X.; Song, M.; Zhan, W.

    2016-12-01

    Serpentinization systems are highly enriched in molecular hydrogen (H2) and hydrocarbons (e.g. methane, ethane and propane). The production of hydrocarbons results from reactions between H2 and oxidized carbon (carbon dioxide and carbon monoxide), which possibly contribute to climate changes during early history of the Earth. However, the influence of silica on the production of H2 and hydrocarbons was poorly constrained. We performed experiments at 311-500 °C and 3.0 kbar using mechanical mixtures of silica and olivine in ratios ranging from 0 to 40%. Molecular hydrogen (H2), methane, ethane and propane were formed, which were analyzed by gas chromatography. It was found that silica largely decreased H2 production. Without any silica, olivine serpentinization produced 94.5 mmol/kg H2 after 20 days of reaction time. By contrast, with the presence of 20% silica, H2 concentrations decreased largely, 8.5 mmol/kg. However, the influence of silica on the production of hydrocarbons is negligible. Moreover, with the addition of 20%-40% silica, the major hydrous minerals are talc, which was quantified according to an established standard curve calibrated by infrared spectroscopy analyses. It shows that silica greatly enhances olivine hydration, especially at 500 °C. Without any addition of silica, reaction extents were serpentinization at 500 °C and 3.0 kbar. By contrast, with the presence of 50% silica, olivine was completely transformed to talc within 9 days. This study indicates that silica impedes the oxidation of ferrous iron into ferric iron, and that rates of olivine hydration in natural geological settings are much faster with silica supply.

  2. Platinum-Group Minerals and Other Accessory Phases in Chromite Deposits of the Alapaevsk Ophiolite, Central Urals, Russia

    Directory of Open Access Journals (Sweden)

    Federica Zaccarini

    2016-10-01

    Full Text Available An electron microprobe study has been carried out on platinum-group minerals, accessory phases, and chromite in several chromite deposits of the Alapaevsk ophiolite (Central Urals, Russia namely the Bakanov Kluch, Kurmanovskoe, Lesnoe, 3-d Podyony Rudnik, Bol’shaya Kruglyshka, and Krest deposits. These deposits occur in partially to totally serpentinized peridotites. The microprobe data shows that the chromite composition varies from Cr-rich to Al-rich. Tiny platinum-group minerals (PGM, 1–10 µm in size, have been found in the chromitites. The most abundant PGM is laurite, accompanied by minor cuproiridsite and alloys in the system Os–Ir–Ru. A small grain (about 20 μm was found in the interstitial serpentine of the Bakanov Kluch chromitite, and its calculated stoichiometry corresponds to (Ni,Fe5P. Olivine, occurring in the silicate matrix or included in fresh chromite, has a mantle-compatible composition in terms of major and minor elements. Several inclusions of amphibole, Na-rich phlogopite, and clinopyroxene have been identified. The bimodal Cr–Al composition of chromite probably corresponds to a vertical distribution in the ophiolite sequence, implying formation of Cr-rich chromitites in the deep mantle, and Al-rich chromitites close to the Moho-transition zone, in a supra-subduction setting. The presence of abundant hydrous silicate inclusions, such as amphibole and phlogopite, suggests that the Alapaevsk chromitites crystallized as a result of the interaction between a melt enriched in fluids and peridotites. Laurite and cuproiridsite are considered to be magmatic in origin, i.e., entrapped as solid phases during the crystallization of chromite at high temperatures. The sulfur fugacity was relatively high to allow the precipitation of Ir-bearing sulfides, but below the Os–OsS2 buffer. The alloys in the system Os–Ir–Ru are classified as secondary PGM, i.e., formed at low temperature during the serpentinization process. The

  3. Specificity of pyrometamorphic minerals of the ellestadite group

    Science.gov (United States)

    Zateeva, S. N.; Sokol, E. V.; Sharygin, V. V.

    2007-12-01

    Numerous rare and new mineral species are synthesized during the process of pyrometamorphism (Gross, 1977; Chesnokov et al., 1987; Chesnokov and Shcherbakova, 1991; Chesnokov, 1999), including silicooxides, chloride-, fluoride, and sulfate-silicates, carbonate-sulfides, chloride-oxides, etc. Having made sense of numerous findings of compounds of this type, Chesnokov (1999) set forth the concept of the crystallochemical transition at extreme temperatures attaining 1200-1450°C in pyrogenic systems. First of all, intertype transitions (oxygen-bearing-oxygen-free) and interclass transitions (chloride-silicate, carbonate-sulfide, chlorideoxide) are realized. The specificity of pyrometamorphic mineral assemblages consists in the abundance of silicates with additional anions (F-, Cl-, (CO3)2-) (Sokol et al., 2005). Minerals of the ellestadite group Ca10(SiO4)3 - x (SO4)3 - x (PO4)2 x (OH,F,Cl)2 are a spectacular example of these features. In the general case, they are silicate-sulfate-phosphate-hydroxide-chlorides-fluorides. The detailed description of these minerals based on the study of the original collection of pyrometamorphic minerals is presented in this paper.

  4. Cancrinite-group minerals behavior at non-ambient conditions

    Science.gov (United States)

    Lotti, Paolo; Gatta, G. Diego; Kahlenberg, Volker; Merlini, Marco; Alvaro, Matteo; Cámara, Fernando

    2014-05-01

    Cancrinite-group minerals occur in the late stages of alkaline (SiO2)-undersaturated magmatism and in related effusive or contact rocks. So far only few studies have been devoted to the description of the thermo-elastic behavior, phase-stability and P /T -structure evolution (at the atomic scale) of this mineral group. Cancrinite-group minerals have an open-framework structure characterized by the [CAN]-topology. The [CAN]-framework shows large 12-ring channels, parallel to the c crystallographic axis, bound by columns of cages, the so-called can units. While very limited chemical variation is observed in the framework composition (the composition is almost always [Si6Al6O24]) a remarkable chemical variability is reported for the extraframework components in the cancrinite-group minerals. Two subgroups can be identified according to the extraframework content of the can units: the cancrinite- and the davyne-subgroups, showing Na-H2O and Ca-Cl chains, respectively. The channels are stuffed by cations, anions and molecules. We aimed to model the thermo-elastic behavior and the mechanisms of the (P ,T)-induced structure evolution of cancrinite-group minerals, with special interest on the role played by the extraframework population. The study was restricted to the following (CO3)-rich and (SO4)-rich end-members: cancrinite sensu stricto {[(Na,Ca)6(CO3)1.2-1.7][Na2(H2O)2][Al6Si6O24]}, vishnevite {[(Na,Ca,K)6(SO4)][Na2(H2O)2][Al6Si6O24]}, balliranoite {[(Na,Ca)6(CO3)1.2-1.7][Ca2Cl2][Al6Si6O24]} and davyne {[(Na,Ca,K)6((SO4),Cl)][Ca2Cl2][Al6Si6O24]}. Their high-P and low-T (T single-crystal X-ray diffraction, using diamond-anvil cells and (N2)-cryosystems, respectively. The high-T behavior of cancrinite has also been studied by means of in-situ single-crystal X-ray diffraction with a resistive heater. Cancrinite minerals share a similar volume compressibility and thermal expansivity at ambient conditions (cancrinite has KV 0 = 45(2) GPa and αV,293K = 4.88(8)·10-5 K-1

  5. Ultramafic clasts from the South Chamorro serpentine mud volcano reveal a polyphase serpentinization history of the Mariana forearc mantle

    Science.gov (United States)

    Kahl, Wolf-Achim; Jöns, Niels; Bach, Wolfgang; Klein, Frieder; Alt, Jeffrey C.

    2015-06-01

    Serpentine seamounts located on the outer half of the pervasively fractured Mariana forearc provide an excellent window into the forearc devolatilization processes, which can strongly influence the cycling of volatiles and trace elements in subduction zones. Serpentinized ultramafic clasts recovered from an active mud volcano in the Mariana forearc reveal microstructures, mineral assemblages and compositions that are indicative of a complex polyphase alteration history. Petrologic phase relations and oxygen isotopes suggest that ultramafic clasts were serpentinized at temperatures below 200 °C. Several successive serpentinization events represented by different vein generations with distinct trace element contents can be recognized. Measured in situ Rb/Cs ratios are fairly uniform ranging between 1 and 10, which is consistent with Cs mobilization from sediments at lower temperatures and lends further credence to the low-temperature conditions proposed in models of the thermal structure in forearc settings. Late veins show lower fluid mobile element (FME) concentrations than early veins, suggesting a decreasing influence of fluid discharge from the subducting slab on the composition of the serpentinizing fluids. The continuous microfabric and mineral chemical evolution observed in the ultramafic clasts may have implications as to the origin and nature of the serpentinizing fluids. We hypothesize that opal and smectite dehydration produce quartz-saturated fluids with high FME contents and Rb/Cs between 1 and 4 that cause the early pervasive serpentinization. The partially serpentinized material may then be eroded from the basal plane of the suprasubduction mantle wedge. Serpentinization continued but the interacting fluids did not carry a pronounced sedimentary signature, either because FMEs were no longer released from the slab, or due to an en route loss of FMEs. Late chrysotile veins that document the increased access of fluids in a now fluid-dominated regime are

  6. Primary occurrence of a vicsite group mineral in the USSR

    International Nuclear Information System (INIS)

    Tarkhanova, G.A.; Sidorenko, G.A.; Moroz, I.Kh.

    1975-01-01

    Uranyl silicate of the viksite group with the formula (Ksub(11)Nasub(0.5)Casub(0.2))(UOsub(2))sub(2)(Sisub(2)Osub(5))sub(3).4-5.8Hsub(2)O has been found for the first time in the USSR in a milybdenum-uranium deposit. The mineral differs from uranyl silicates of the uranophane and the kasolite group in having a high stability of its crystalline structure and a wide cation isomorphism exhibiting no changes in the crystalline structure

  7. Nuclear microprobe analysis of serpentine from the mid-Atlantic ridge

    International Nuclear Information System (INIS)

    Orberger, Beate; Metrich, Nicole; Mosbah, Michelle; Mevel, Catherine; Fouquet, Yves

    1999-01-01

    At mid-ocean ridges, ultramafic rocks are serpentinized by interaction with seawater-derived fluids. Elements, dissolved in large quantities in seawater, e.g., Na, K, Cl, Br, Ca and Sr, can be, in small amounts, incorporated as traces into the crystal structure of the various serpentine minerals (Mg 3 Si 2 O 5 (OH) 4 ). These trace elements can be used to track the composition of the reacting fluids and to constrain physico-chemical conditions. This paper represents the first application of particle-induced X- and γ-ray emission (PIXE/PIGE) analysis to serpentine using the nuclear microprobe at the Laboratoire Pierre Suee (CEA-CNRS). Three types of serpentine, belonging to two different serpentinization generations, have been analysed in samples collected from the Mid-Atlantic Ridge (14 deg. 45'N/45 deg. W) that exposes serpentinized peridotites on which the Logachev black smoker is placed. The trace elements Cl, F, S, Cu, Zn, Ca, K, Ni, Cr and Mn were detected from several tens to several thousands of ppm. Bromine, As and Sr are close to the detection limit of about 5 ppm. The trace element concentrations and interelement relationships in serpentines vary (a) with the serpentine type and (b) with the geographic location to the black smoker. Chlorine and in part S originated from seawater, whereas Cu, Zn, Ca, K, Ni, Cr and Fe and the major amount of S were mobilized from the unaltered host rock and partitioned between the serpentine and the aqueous solution

  8. Shielded serpentine traveling wave tube deflection structure

    Science.gov (United States)

    Hudson, C.L.; Spector, J.

    1994-12-27

    A shielded serpentine slow wave deflection structure is disclosed having a serpentine signal conductor within a channel groove. The channel groove is formed by a serpentine channel in a trough plate and a ground plane. The serpentine signal conductor is supported at its ends by coaxial feed through connectors. A beam interaction trough intersects the channel groove to form a plurality of beam interaction regions wherein an electron beam may be deflected relative to the serpentine signal conductor. 4 figures.

  9. Mineral composition of enamel from two South African population groups

    Energy Technology Data Exchange (ETDEWEB)

    Retief, D H [University of the Witwatersrand, Johannesburg (South Africa). Dental Research Unit; Turkstra, J [University of Fort Hare, Alice (South Africa). Department of Chemistry; Cleaton-Jones, P E; Biddlecombe, F [Atomic Energy Board, Pelindaba, Pretoria (South Africa). Chemistry Div.

    1979-10-01

    The mineral composition of pooled bulk enamel from Black and White South Africans respectively, resident in the Johannesburg area, was determined by neutron activation analysis and high resolution gamma spectromety. The differences between the concentrations of Ca, Cl, Mg, Na, Br and Co in the enamel of the two population groups were apparently not significant. There was a trend for the concentrations of Al, Ag, Au, Fe, Sb, and Zn to be higher in the enamel from the White subjects and for the concentrations of Mn, Se and Sr to be higher in the enamel from the Black subjects.

  10. Serpentinization history of the Río Guanajibo serpentinite body, Puerto Rico

    Science.gov (United States)

    Roehrig, Erin E.; Laó-Dávila, Daniel A.; Wolfe, Amy L.

    2015-10-01

    The Río Guanajibo serpentinite body (RGSB) near Mayagüez, Puerto Rico, is part of an ophiolite mélange thrust in an oceanic convergent zone. The aim of this study was to characterize the extent and chronology of serpentinization within this peridotite mass. Mineralogy, microstructures, and veining episodes within the RGSB were characterized using optical microscopy, x-ray diffraction (XRD), scanning electron microscopy (SEM), and structural analyses. This study identified, for the first time, all three serpentine polymorphs (i.e., antigorite, chrysotile, lizardite) in serpentinite samples collected from Puerto Rico. Lizardite, the initial serpentine mineral formed from widespread hydration of olivine, was found throughout serpentinite samples. Chrysotile was the most abundant polymorph observed in sheared serpentinite samples, consistent with conditions favoring low fluid to rock ratios, supersaturation and abundant porosity. Antigorite was observed as a replacement texture in serpentinites that were not exposed to greenschist facies metamorphic conditions, and were frequently found in veins with a shear component. The results indicate that metamorphic conditions do not exclusively dictate polymorph formation. The mineralogy and textures observed within the different vein generations reflect the formation conditions, and deformational mechanisms, that occurred during the serpentinization process; six veining episodes (V1 - V6) were identified and grouped into four stages of serpentinization. Stage one (V1 and V2 type veins) represents the earliest stages of serpentinization and was characterized by microscopic fracture networks that formed as a result of cracking during the initial hydration of olivine under low water/rock ratios. During stage two (V3 and V4 type veins), fibrous crack - seal veins formed to accommodate continued volume expansion, via incremental fracture openings, caused by continued hydration of olivine. The ascension of serpentinite into the

  11. Microfracturing and fluid pathways in serpentinizing abyssal peridotites along the Southwest Indian Ridge (62°-65°E)

    Science.gov (United States)

    Rouméjon, S.; Cannat, M.; Agrinier, P.; Godard, M.; Andreani, M.

    2013-12-01

    conditions associated with this serpentinization history and to discuss the nature of serpentinizing fluids, based on a comparison with published work on serpentinites from the Mid-Atlantic Ridge. δ18O values decrease from 5.98‰ to 1.91‰, from mesh texture serpentine to the later recrystallized serpentines. These values probably correspond to temperatures on the order of 200-300°C and to a progressive equilibration with serpentinizing fluid values due to increasing water-rock ratios. Fluid-rock interactions produce serpentine minerals that are enriched in fluid-mobile elements (B, As, Sb, U, Cu) compared to primary minerals in the peridotites and present occasional Eu anomalies that may reflect variable redox conditions during serpentinization.

  12. [Vitamin and minerals consumed food group by Chilean university students].

    Science.gov (United States)

    Durán Aguero, Samuel; Reyes García, Susanne; Gaete, María Cristina

    2013-01-01

    The lifestyle changes in college, students go through periods of physical inactivity and irregular meal times, which leads to increased consumption of processed foods and fast food. To calculate vitamins and minerals intakes for groups in the diet of Chilean university students. We studied 654 university students (18 to 24 years, 54% female), a 7-day food frequency questionnaire was used for dietary assessment, the information collected was classified into 12 groups representing each set of food, and then nutrient intake was determined. The main results were: (a) women had lower intake of most micronutrients than men (b) pantothenic acid, vitamin B12 and E, calcium, magnesium and iron are nutrients that showed mean intakes below the daily recommendations, (c) the consumption of bread is essential for the supply of B vitamins, iron, copper and selenium. In the usual diet of college students, bread is a key to the dietary intake of B vitamins, iron, copper and selenium, as well as dairy products for calcium, meat and fish for vitamin B12 and zinc; vegetables for vitamin A and fruits for vitamin C. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

  13. D/H diffusion in serpentine

    Science.gov (United States)

    Pilorgé, Hélène; Reynard, Bruno; Remusat, Laurent; Le Floch, Sylvie; Montagnac, Gilles; Cardon, Hervé

    2017-08-01

    Interactions between aqueous fluids and ultrabasic rocks are essential processes in a broad range of contexts including hydrothermal alteration on the parent body of carbonaceous chondrites, at mid-oceanic ridge, and in subduction zones. Tracking these processes and understanding reaction kinetics require knowledge of the diffusion of water in rocks, and of isotope fractionation in major minerals forming under hydrous conditions, such as serpentines. We present a study of D/H inter-diffusion in antigorite, a common variety of serpentine. Experiments were performed in a belt apparatus at 315 °C, 450 °C and 540 °C and at 3.0 GPa on natural antigorite powders saturated with interstitial D2O. An experiment was performed in a diamond anvil cell at 350 °C and 2.5 GPa on an antigorite single-crystal loaded with pure D2O. D/(D + H) ratios were mapped using Raman spectroscopy for the experiments at 315 °C, 450 °C and 540 °C and by NanoSIMS for the experiment at 350 °C. As antigorite is a phyllosilicate, diffusion coefficients were obtained for crystallographic directions parallel and perpendicular to the silicate layers (perpendicular and parallel to the c∗-axis, respectively). Arrhenius relations for D/H inter-diffusion coefficients were determined to be DD/H (m2/s) = 4.71 × 10-2 × exp(-207(-33/+58) (kJ/mol)/RT) and DD/H (m2/s) = 1.61 × 10-4 × exp(-192(-34/+93) (kJ/mol)/RT) perpendicular and parallel to the c∗-axis, respectively, and DD/H (m2/s) = 7.09 × 10-3 × exp(-202(-33/+70) (kJ/mol)/RT) for the bulk diffusivity. Assuming D/H inter-diffusion coefficients for antigorite are the same for all serpentine species, closure temperature and diffusion durations are applied to hydrothermal alteration in the oceanic lithosphere, and in CI, CM and CR chondrites. Closure temperatures lie below 300 °C for terrestrial hydrothermal alteration and depend on serpentine variety because they have different typical grain sizes. Closure temperatures lie below 160 °C for

  14. Radiation color and electron-hole centers of serpentines

    International Nuclear Information System (INIS)

    Lyutoev, V.P.; Yukhtanov, P.P.

    1999-01-01

    Radiation-induced coloring of serpentine (Mg 3 [Si 2 O 5 ](OH) 4 ), gamma radiation dose being 30 Mrad, is studied by the ESR and absorption spectroscopy methods. It is ascertained that ionizing radiation gives rise to formation of radiation centers on the mineral basic structural elements. paramagnetic centers and coloring centers, relating to radiation centers, stem from the same type of defects - O - oxygen centers, formed as a result of radiation-induced break of OH-bonds [ru

  15. Study of thermal, radiation and environmental effects on serpentine

    International Nuclear Information System (INIS)

    Raje, Naina; Kalekar, Bhupesh B.; Dubey, K.A.

    2016-01-01

    Physical and chemical properties of a material, such as particle size surface area, magnetic properties, water content, radiation and thermal stability, viscosity, porosity, are responsible for their specific applications. Serpentine is a greenish, layer structured phyllosilicate, known as magnesium hydroxy silicate. The availability of large number of hydroxyl group makes serpentine a potential candidate for nuclear shielding material. Hence present studies have been carried out to understand the stability of serpentine with the variation in thermal, radiation and environmental parameters. Serpentine samples were received from Reactor Projects Division, BARC. An accurately weighed sample was subjected to simultaneous TG - DTA - EGA measurements in air as well as inert atmosphere at the heating rate of 10 °C/min. The sample was heated from room temperature to 1000 °C with a gas flow rate of 100 mL/min in Netzsch thermal analyzer (Model STA409 PC LUXX) connected to Bruker FTIR system (Model - Tensor27) via a 1m long capillary. The sample was subjected to gamma radiation in the range of 10 - 100 kGy using 60 Co gamma source in gamma chamber and was subjected to TG measurements to understand the effect of radiation on the thermal stability of serpentine and the results are being discussed here

  16. Biological Potential in Serpentinizing Systems

    Science.gov (United States)

    Hoehler, Tori M.

    2016-01-01

    Generation of the microbial substrate hydrogen during serpentinization, the aqueous alteration of ultramafic rocks, has focused interest on the potential of serpentinizing systems to support biological communities or even the origin of life. However the process also generates considerable alkalinity, a challenge to life, and both pH and hydrogen concentrations vary widely across natural systems as a result of different host rock and fluid composition and differing physical and hydrogeologic conditions. Biological potential is expected to vary in concert. We examined the impact of such variability on the bioenergetics of an example metabolism, methanogenesis, using a cell-scale reactive transport model to compare rates of metabolic energy generation as a function of physicochemical environment. Potential rates vary over more than 5 orders of magnitude, including bioenergetically non-viable conditions, across the range of naturally occurring conditions. In parallel, we assayed rates of hydrogen metabolism in wells associated with the actively serpentinizing Coast Range Ophiolite, which includes conditions more alkaline and considerably less reducing than is typical of serpentinizing systems. Hydrogen metabolism is observed at pH approaching 12 but, consistent with the model predictions, biological methanogenesis is not observed.

  17. Fibrous Platinum-Group Minerals in “Floating Chromitites” from the Loma Larga Ni-Laterite Deposit, Dominican Republic

    Directory of Open Access Journals (Sweden)

    Thomas Aiglsperger

    2016-11-01

    Full Text Available This contribution reports on the observation of enigmatic fibrous platinum-group minerals (PGM found within a chromitite body included in limonite (“floating chromitite” from Ni-laterites in the Dominican Republic. Fibrous PGM have a Ru-Os-Ir-Fe dominated composition and are characterized by fibrous textures explained by grain-forming fibers which are significantly longer (1–5 µm than they are wide (~100 nm. Back-scattered electron (BSE images suggest that these nanofibers are platinum-group elements (PGE-bearing and form <5 µm thick layers of bundles which are oriented orthogonal to grains’ surfaces. Trace amounts of Si are most likely associated with PGE-bearing nanofibers. One characteristic fibrous PGM was studied in detail: XRD analyses point to ruthenian hexaferrum. However, the unpolished fibrous PGM shows numerous complex textures on its surface which are suggestive for neoformation processes: (i features suggesting growth of PGE-bearing nanofibers; (ii occurrence of PGM nanoparticles within film material (biofilm? associated with PGE-bearing nanofibers; (iii a Si-rich and crater-like texture hosting PGM nanoparticles and an Ir-rich accumulation of irregular shape; (iv complex PGM nanoparticles with ragged morphologies, resembling sponge spicules and (v oval forms (<1 µm in diameter with included PGM nanoparticles, similar to those observed in experiments with PGE-reducing bacteria. Fibrous PGM found in the limonite may have formed due to supergene (bio-weathering of fibrous Mg-silicates which were incorporated into desulphurized laurite during stages of serpentinization.

  18. Platinum-group elements in southern Africa: mineral inventory and an assessment of undiscovered mineral resources: Chapter Q in Global mineral resource assessment

    Science.gov (United States)

    Zientek, Michael L.; Causey, J. Douglas; Parks, Heather L.; Miller, Robert J.

    2014-01-01

    The platinum-group elements, platinum, palladium, rhodium, ruthenium, iridium, and osmium, possess unique physical and chemical characteristics that make them indispensable to modern technology and industry. However, mineral deposits that are the main sources of these elements occur only in three countries in the world, raising concerns about potential disruption in mineral supply. Using information in the public domain, mineral resource and reserve information has been compiled for mafic and ultramafic rocks in South Africa and Zimbabwe that host most of the world’s platinum-group element resources.

  19. Mineralogy of accessory and rare minerals associated with chromite deposits in the Khoy area

    International Nuclear Information System (INIS)

    Emamalipour, A.

    2008-01-01

    The chromite deposits in the Khoy area have lenticular, tubular and vein-like shapes which are found in serpenlinized hurzburgite. Chromite and serpentine are major minerals and hematite and magnetite are minor phases in the chromitic ores .Furthermore, Fe, Ni, Cu, Co, Zn, Ru, Os, Ir, La, Ce, Gd and S elements are found as base metal sulfides, sulfides of platinum group elements, metal oxides, native elements, natural alloys and solid inclusions in chromite grains and or in serpentinic ground mass. These minerals have very fine grain sizes and recognitions of them by ore microscopic method was limited, so the investigations were continued by EMPA. The majority of these minerals have secondary origin and are related with serpentinization. processes and only a few of them have primary origin. Among sulfide minerals bravoite, pyrotite, milerite, linaite and pyrite have secondary origin, whereas pentlandite has primary one. Chalcopyrite has been formed in two generations, as both primary and secondary origins. Among primary platinum group elements minerals lourite ((Ru, Os, Ir)S 2 ) is considerable, which was found as a solid inclusion in the chromite grain and has primary origin. Native metals and natural alloys such as nickel, copper, iron and josephinite (Ni 3 Fe) have been formed in micro fractures of chromite grains filled by serpentine. A few rare earth element-rich compositions were found in micro fractures also and have secondary origin

  20. Minerals

    Science.gov (United States)

    Minerals are important for your body to stay healthy. Your body uses minerals for many different jobs, including keeping your bones, muscles, heart, and brain working properly. Minerals are also important for making enzymes and hormones. ...

  1. Raman Spectroscopy of Serpentine and Reaction Products at High Pressure Using a Diamond Anvil Cell

    Science.gov (United States)

    Burgess, K.; Zinin, P.; Odake, S.; Fryer, P.; Hellebrand, E.

    2012-12-01

    Serpentine is one of the most abundant hydrous phases in the altered subducting plate, and contributes a large portion of the water flux in subduction zones. Measuring and understanding the structural changes in serpentine with pressure aids our understanding of the processes ongoing in oceanic crust and subduction zones. We have conducted high-pressure/high-temperature experiments on serpentine and its dehydration reaction products using a diamond anvil cell. We used the multifunctional in-situ measurement system equipped with a Raman device and laser heating system at the University of Hawaii. Well-characterized natural serpentinite was used in the study. Pressure was determined using the shift of the fluorescence line of a ruby placed next to the sample. Raman spectra of serpentine were obtained at higher pressures than previously published, up to 15 GPa; the peak shift with pressure fits the model determined by Auzende et al. [2004] at lower pressures. Heating was done at several different pressures up to 20 GPa, and reaction products were identified using Raman. Micro-Raman techniques allow us to determine reaction progress and heterogeneity within natural samples containing olivine and serpentine. Auzende, A-L., I. Daniel, B. Reynard, C. Lemaire, F. Guyot (2004). High-pressure behavior of serpentine minerals: a Raman spectroscopic study. Phys. Chem. Minerals 31 269-277.

  2. Nuclear microprobe analysis of serpentine from the mid-Atlantic ridge

    Energy Technology Data Exchange (ETDEWEB)

    Orberger, Beate E-mail: orberger@geol.u-psud.fr; Metrich, Nicole; Mosbah, Michelle E-mail: mosbah@drecam.cea.fr; Mevel, Catherine; Fouquet, Yves

    1999-09-02

    At mid-ocean ridges, ultramafic rocks are serpentinized by interaction with seawater-derived fluids. Elements, dissolved in large quantities in seawater, e.g., Na, K, Cl, Br, Ca and Sr, can be, in small amounts, incorporated as traces into the crystal structure of the various serpentine minerals (Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}). These trace elements can be used to track the composition of the reacting fluids and to constrain physico-chemical conditions. This paper represents the first application of particle-induced X- and {gamma}-ray emission (PIXE/PIGE) analysis to serpentine using the nuclear microprobe at the Laboratoire Pierre Suee (CEA-CNRS). Three types of serpentine, belonging to two different serpentinization generations, have been analysed in samples collected from the Mid-Atlantic Ridge (14 deg. 45'N/45 deg. W) that exposes serpentinized peridotites on which the Logachev black smoker is placed. The trace elements Cl, F, S, Cu, Zn, Ca, K, Ni, Cr and Mn were detected from several tens to several thousands of ppm. Bromine, As and Sr are close to the detection limit of about 5 ppm. The trace element concentrations and interelement relationships in serpentines vary (a) with the serpentine type and (b) with the geographic location to the black smoker. Chlorine and in part S originated from seawater, whereas Cu, Zn, Ca, K, Ni, Cr and Fe and the major amount of S were mobilized from the unaltered host rock and partitioned between the serpentine and the aqueous solution.

  3. Beaufort group uranium mineralization - a model that may aid exploration

    International Nuclear Information System (INIS)

    Stuart-Williams, V.

    1982-01-01

    The ore bodies examined while working on the Pristerognathus Diictodon Assemblage Zone West of Beaufort West are of the URAVAN type (URA - uranium, VAN - vanadium). It was found that uranium mineralization in any one ore body was not strictly random and tends to be associated with a fairly consistent sandstone and siltstone geometry. Mineralization is only found where coalescence between the two sandstones has occurred and it disappears where the sandstones remain coalesced. At a point of coalescence the fluids from the upper and lower sandstone are mixed, the oxidizing fluid penetrating progressively deeper in the sandstone couplet until the entire couplet is oxidizing. This generates a weakly dipping REDOX front. The REDOX front is not considered strong enough to have precipitated uranyl carbonate complexes in transport

  4. Characterization of carbonated serpentine using XPS and TEM

    International Nuclear Information System (INIS)

    Schulze, Roland K.; Hill, Mary Ann; Field, Robert D.; Papin, Pallas A.; Hanrahan, Robert J.; Byler, Darrin D.

    2004-01-01

    With the increasing concentration volume of carbon dioxide in the atmosphere, there has been an increasing interest in carbon dioxide sequestration. One method is to store the carbon dioxide in mineral form, reacting solution dissolved CO 2 to precipitate carbonates. In order to understand whether or not such an endeavor is feasible, the carbonation reaction must first be understood. In this study, the surface of ground serpentine, untreated, heat treated and following a carbonation experiment, has been characterized using X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The results indicate that the mechanism for the reaction involves dissolution of the serpentine through the formation of an amorphous phase and subsequent precipitation of magnesite. The rate limiting step appears to be the diffusion of Mg out of the amorphous phase

  5. Biogeochemical weathering of serpentinites: An examination of incipient dissolution affecting serpentine soil formation

    International Nuclear Information System (INIS)

    Baumeister, Julie L.; Hausrath, Elisabeth M.; Olsen, Amanda A.; Tschauner, Oliver; Adcock, Christopher T.; Metcalf, Rodney V.

    2015-01-01

    Highlights: • Dissolution of primary minerals is important to porosity generation in serpentinites. • Mineral weathering extent in serpentinites follows the order Fe > Mg > Al rich minerals. • Fe-oxidizing bacteria may mediate Fe-rich primary and serpentine mineral alteration. • Serpentinite weathering is strongly impacted by degree of serpentinization. - Abstract: Serpentinite rocks, high in Mg and trace elements including Ni, Cr, Cd, Co, Cu, and Mn and low in nutrients such as Ca, K, and P, form serpentine soils with similar chemical properties resulting in chemically extreme environments for the biota that grow upon them. The impact of parent material on soil characteristics is most important in young soils, and therefore the incipient weathering of serpentinite rock likely has a strong effect on the development of serpentine soils and ecosystems. Additionally, porosity generation is a crucial process in converting rock into a soil that can support vegetation. Here, the important factors affecting the incipient weathering of serpentinite rock are examined at two sites in the Klamath Mountains, California. Serpentinite-derived soils and serpentinite rock cores were collected in depth profiles from each sampling location. Mineral dissolution in weathered serpentinite samples, determined by scanning electron microscopy, energy dispersive spectrometry, electron microprobe analyses, and synchrotron microXRD, is consistent with the order, from most weathered to least weathered: Fe-rich pyroxene > antigorite > Mg-rich lizardite > Al-rich lizardite. These results suggest that the initial porosity formation within serpentinite rock, impacting the formation of serpentine soil on which vegetation can exist, is strongly affected both by the presence of non-serpentine primary minerals as well as the composition of the serpentine minerals. In particular, the presence of ferrous Fe appears to contribute to greater dissolution, whereas the presence of Al within the

  6. Geochemical models of metasomatism in ultramafic systems: Serpentinization, rodingitization, and sea floor carbonate chimney precipitation

    Science.gov (United States)

    Palandri, J.L.; Reed, M.H.

    2004-01-01

    In a series of water-rock reaction simulations, we assess the processes of serpentinization of harzburgite and related calcium metasomatism resulting in rodingite-type alteration, and seafloor carbonate chimney precipitation. At temperatures from 25 to 300??C (P = 10 to 100 bar), using either fresh water or seawater, serpentinization simulations produce an assemblage commonly observed in natural systems, dominated by serpentine, magnetite, and brucite. The reacted waters in the simulations show similar trends in composition with decreasing water-rock ratios, becoming hyper-alkaline and strongly reducing, with increased dissolved calcium. At 25??C and w/r less than ???32, conditions are sufficiently reducing to yield H2 gas, nickel-iron alloy and native copper. Hyperalkalinity results from OH- production by olivine and pyroxene dissolution in the absence of counterbalancing OH- consumption by alteration mineral precipitation except at very high pH; at moderate pH there are no stable calcium minerals and only a small amount of chlorite forms, limited by aluminum, thus allowing Mg2+ and Ca2+ to accumulate in the aqueous phase in exchange for H+. The reducing conditions result from oxidation of ferrous iron in olivine and pyroxene to ferric iron in magnetite. Trace metals are computed to be nearly insoluble below 300??C, except for mercury, for which high pH stabilizes aqueous and gaseous Hg??. In serpentinization by seawater at 300??C, Ag, Au, Pd, and Pt may approach ore-forming concentrations in sulfide complexes. Simulated mixing of the fluid derived from serpentinization with cold seawater produces a mineral assemblage dominated by calcite, similar to recently discovered submarine, ultramafic rock-hosted, carbonate mineral deposits precipitating at hydrothermal vents. Simulated reaction of gabbroic or basaltic rocks with the hyperalkaline calcium- and aluminum-rich fluid produced during serpentinization at 300??C yields rodingite-type mineral assemblages, including

  7. Characterizing and quantifying superparamagnetic magnetite particles in serpentinized mantle peridotite observed in continental ophiolite complexes.

    Science.gov (United States)

    Ortiz, E.; Vento, N. F. R.; Tominaga, M.; Beinlich, A.; Einsle, J. F.; Buisman, I.; Ringe, E.; Schrenk, M. O.; Cardace, D.

    2017-12-01

    Serpentinization of mantle peridotite has been recognized as one of the most important energy factories for the deep biosphere. To better evaluate the habitability of the deep biosphere, it is crucial to understand the link between in situ peridotite serpentinization processes and associated magnetite and hydrogen production. Previous efforts in correlating magnetite and hydrogen production during serpentinization processes are based primarily on laboratory experiments and numerical modeling, being challenged to include the contribution of superparamagnetic-sized magnetites (i.e., extremely fine-grained magnetite, petrographically observed as a "pepper flake" like texture in many natural serpentinized rock samples). To better estimate the abundance of superparamagnetic grains, we conducted frequency-dependent susceptibility magnetic measurements at the Institute of Rock Magnetism on naturally serpentinized rock samples from the Coast Range Ophiolite Microbial Observatory (CROMO) in California, USA and the Atlin Ophiolite (British Columbia). In addition, we conducted multiscale EDS phase mapping, BackScattered Electron (BSE) scanning, FIB-nanotomography and STEM-EELS to identify and quantify the superparamagnetic minerals that contribute to the measured magnetic susceptibility signals in our rock samples. Utilizing a multidisciplinary approach, we aim to improve the estimation of hydrogen production based on the abundance of magnetite, that includes the contribution of superparamagnetic particle size magnetite, to ultimately provide a more accurate estimation of bulk deep-biomass hosted by in situ serpentinization processes.

  8. The production of iron oxide during peridotite serpentinization: Influence of pyroxene

    Directory of Open Access Journals (Sweden)

    Ruifang Huang

    2017-11-01

    Full Text Available Serpentinization produces molecular hydrogen (H2 that can support communities of microorganisms in hydrothermal fields; H2 results from the oxidation of ferrous iron in olivine and pyroxene into ferric iron, and consequently iron oxide (magnetite or hematite forms. However, the mechanisms that control H2 and iron oxide formation are poorly constrained. In this study, we performed serpentinization experiments at 311 °C and 3.0 kbar on olivine (with <5% pyroxene, orthopyroxene, and peridotite. The results show that serpentine and iron oxide formed when olivine and orthopyroxene individually reacted with a saline starting solution. Olivine-derived serpentine had a significantly lower FeO content (6.57 ± 1.30 wt.% than primary olivine (9.86 wt.%, whereas orthopyroxene-derived serpentine had a comparable FeO content (6.26 ± 0.58 wt.% to that of primary orthopyroxene (6.24 wt.%. In experiments on peridotite, olivine was replaced by serpentine and iron oxide. However, pyroxene transformed solely to serpentine. After 20 days, olivine-derived serpentine had a FeO content of 8.18 ± 1.56 wt.%, which was significantly higher than that of serpentine produced in olivine-only experiments. By contrast, serpentine after orthopyroxene had a slightly higher FeO content (6.53 ± 1.01 wt.% than primary orthopyroxene. Clinopyroxene-derived serpentine contained a significantly higher FeO content than its parent mineral. After 120 days, the FeO content of olivine-derived serpentine decreased significantly (5.71 ± 0.35 wt.%, whereas the FeO content of orthopyroxene-derived serpentine increased (6.85 ± 0.63 wt.% over the same period. This suggests that iron oxide preferentially formed after olivine serpentinization. Pyroxene in peridotite gained some Fe from olivine during the serpentinization process, which may have led to a decrease in iron oxide production. The correlation between FeO content and SiO2 or Al2O3 content in olivine- and

  9. Geochemical evidence of present-day serpentinization.

    Science.gov (United States)

    Barnes, I; Lamarche, V C; Himmelberg, G

    1967-05-12

    Ultrabasic (pH > 11) water issues from some fresh ultramafic bodies. The properties of the ultrabasic solutions are believed to be due to current reactions yielding serpentine from primary olivines and pyroxenes. The low concentrations of divalent airon. divalent magnesium, and dissolved silica from the serpentinization require an increase in rock volume.

  10. Giant serpentine intracranial aneurysm: a case report

    International Nuclear Information System (INIS)

    Park, Jae Seong; Lee, Myeong Sub; Kim, Myung Soon; Kim, Dong Jin; Park, Joong Wha; Whang, Kum

    2001-01-01

    The authors present a case of giant serpentine aneurysm (a partially thrombosed aneurysm containing tortuous vascular channels with a separate entrance and outflow pathway). Giant serpentine aneurysms form a subgroup of giant intracranial aneurysms, distinct from saccular and fusiform varieties, and in this case, too, the clinical presentation and radiographic features of CT, MR imaging and angiography were distinct

  11. Nickel speciation in several serpentine (ultramafic) topsoils via bulk synchrotron-based techniques

    Energy Technology Data Exchange (ETDEWEB)

    Siebecker, Matthew G.; Chaney, Rufus L.; Sparks, Donald L.

    2017-07-01

    Serpentine soils have elevated concentrations of trace metals including nickel, cobalt, and chromium compared to non-serpentine soils. Identifying the nickel bearing minerals allows for prediction of potential mobility of nickel. Synchrotron-based techniques can identify the solid-phase chemical forms of nickel with minimal sample treatment. Element concentrations are known to vary among soil particle sizes in serpentine soils. Sonication is a useful method to physically disperse sand, silt and clay particles in soils. Synchrotron-based techniques and sonication were employed to identify nickel species in discrete particle size fractions in several serpentine (ultramafic) topsoils to better understand solid-phase nickel geochemistry. Nickel commonly resided in primary serpentine parent material such as layered-phyllosilicate and chain-inosilicate minerals and was associated with iron oxides. In the clay fractions, nickel was associated with iron oxides and primary serpentine minerals, such as lizardite. Linear combination fitting (LCF) was used to characterize nickel species. Total metal concentration did not correlate with nickel speciation and is not an indicator of the major nickel species in the soil. Differences in soil texture were related to different nickel speciation for several particle size fractionated samples. A discussion on LCF illustrates the importance of choosing standards based not only on statistical methods such as Target Transformation but also on sample mineralogy and particle size. Results from the F-test (Hamilton test), which is an underutilized tool in the literature for LCF in soils, highlight its usefulness to determine the appropriate number of standards to for LCF. EXAFS shell fitting illustrates that destructive interference commonly found for light and heavy elements in layered double hydroxides and in phyllosilicates also can occur in inosilicate minerals, causing similar structural features and leading to false positive results in

  12. Mantle wedge serpentinization effects on slab dips

    Directory of Open Access Journals (Sweden)

    Eh Tan

    2017-01-01

    Full Text Available The mechanical coupling between a subducting slab and the overlying mantle wedge is an important factor in controlling the subduction dip angle and the flow in mantel wedge. This paper investigates the role of the amount of mantle serpentinization on the subduction zone evolution. With numerical thermos-mechanical models with elasto-visco-plastic rheology, we vary the thickness and depth extent of mantle serpentinization in the mantle wedge to control the degree of coupling between the slab and mantle wedge. A thin serpentinized mantle layer is required for stable subduction. For models with stable subduction, we find that the slab dip is affected by the down-dip extent and the mantle serpentinization thickness. A critical down-dip extent exists in mantle serpentinization, determined by the thickness of the overriding lithosphere. If the down-dip extent does not exceed the critical depth, the slab is partially coupled to the overriding lithosphere and has a constant dip angle regardless of the mantle serpentinization thickness. However, if the down-dip extent exceeds the critical depth, the slab and the base of the overriding lithosphere would be separated and decoupled by a thick layer of serpentinized peridotite. This allows further slab bending and results in steeper slab dip. Increasing mantle serpentinization thickness will also result in larger slab dip. We also find that with weak mantle wedge, there is no material flowing from the asthenosphere into the serpentinized mantle wedge. All of these results indicate that serpentinization is an important ingredient when studying the subduction dynamics in the mantle wedge.

  13. Cathodoluminescence (CL) and electron paramagnetic resonance (EPR) studies of clay minerals

    International Nuclear Information System (INIS)

    Goetze, J.; Ploetze, M.; Goette, T.; Neuser, R.D.; Richter, D.K.

    2002-01-01

    Sheet silicates of the serpentine-kaolin-group (serpentine, kaolinite, dickite, nacrite, halloysite), the talc-pyrophyllite-group (talc, pyrophyllite), the smectite-group (montmorillonite), and illite (as a mineral of the mica-group) were investigated to obtain information concerning their cathodoluminescence behavior. The study included analyses by cathodoluminescence (CL microscopy and spectroscopy), electron paramagnetic resonance (EPR), x-ray diffraction (XRD), scanning electron microscopy (SEM) and trace element analysis. In general, all dioctahedral clay minerals exhibit a visible CL. Kaolinite, dickite, nacrite and pyrophyllite have a characteristic deep blue CL, whereas halloysite emission is in the greenish-blue region. On the contrary, the trioctahedral minerals (serpentine, talc) and illite do not show visible CL. The characteristic blue CL is caused by an intense emission band around 400 nm (double peak with two maxima at 375 and 410 nm). EPR measurements indicate that his blue emission can be related to radiation induced defect centers (RID), which occur as electron holes trapped on apical oxygen (Si-O center) or located at the Al-O-Al group (Al substituting Si in the tetrahedron). Additional CL emission bands were detected at 580 nm in halloysite and kaolinite, and between 700 and 800 nm in kaolinite, dickite, nacrite and pyrophyllite. Time-resolved spectral CL measurements show typical luminescence kinetics for the different clay minerals, which enable differentiation between the various dioctahedral minerals (e.g. kaolinite and dickite), even in thin section. (author)

  14. Micro-, to nano-structural relationships in natural serpentines, derived from cationic substitutions.

    Science.gov (United States)

    Munoz, M.; Farges, F.; Andreani, M.; Ulrich, M.; Marcaillou, C.; Mathon, O.

    2014-12-01

    The understanding of the crystal chemistry of serpentine minerals (incl. antigorite, lizardite and chrysotile) is fundamental since serpentinization processes concern very large scientific domains: e.g., natural abiotic hydrogen production (Marcaillou et al., 2011), origins of life (Russell et al., 2010), fluid properties and mobility of metals in subduction zones (Kelley and Cottrell, 2009). This study aims at characterizing relations between the micro-, and nano-structures of the most abundant serpentine polytypes in the oceanic crust. Serpentine theoretical formula is Mg3Si2O5(OH)4 but several natural substitutions are possible and the formula may be written such as: (Mg,Fe2+,Fe3+,Al)3(Si,Al,Fe3+)2O5(OH)4; showing that Fe and Al may play an important role in the crystallization of serpentines. Preliminary crystal chemistry studies, suggest that, 1) the Al content alone cannot be directly correlated to serpentine polytypes (Andreani et al., 2008), 2) the amounts of tetrahedral iron can be significant in the presence of ferric iron (Marcaillou et al., 2011). Because magnetite is usually associated to serpentine, the Fe-speciation characterization of serpentine is delicate. Here, we provide the study of 33 magnetite-free serpentines containing various amounts of Fe and Al. The samples were characterized by SEM, Raman, XRF, as well as XANES, pre-edge, and EXAFS spectroscopy at the Fe K-edge. XANES experimental data were crosschecked and interpreted thanks to ab initio calculations and EXAFS shell-fitting. Also, preliminary 27Al-RMN data is presented. Results suggest relationships between the type and amount of substitution of trivalent cations in minerals, and the microstructures observed. Chrysotile incorporates less trivalent cations than other varieties, which tends to preserve the so-called misfit between the TO layers, and therefore the tubular structure of the mineral. Lizardites mainly involve Fe/Al Tschermak-type substitutions, while M-site vacancy charge

  15. Effects of functional groups and soluble matrices in fish otolith on calcium carbonate mineralization

    Energy Technology Data Exchange (ETDEWEB)

    Ren Dongni; Li Zhuo; Gao Yonghua; Feng Qingling, E-mail: biomater@mail.tsinghua.edu.c [State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2010-10-01

    Calcium carbonate mineralization is significantly influenced by organic matrices in vivo. The effect mainly relies on functional groups in proteins. In order to study the influence of functional groups on calcium carbonate mineralization, -OH, -NH{sub 2} and -COOH groups were grafted onto single crystal silicon chips, and such modified chips were used as substrates in in vitro mineralization experiments. An x-ray photoelectron spectroscopy (XPS) test was conducted to examine the grafting efficiency, and the three groups were successfully grafted. Calcium carbonate mineralization on a modified silicon substrate was examined by a scanning electron microscope (SEM) and x-ray diffraction (XRD), and the results showed that the effects of -OH, -NH{sub 2} and -COOH groups were quite different. Furthermore, a water-soluble protein matrix (WSM) and an acid-soluble protein matrix (ASM) extracted from fish otolith were adsorbed onto the -COOH-modified silicon substrate, and the effects of the protein matrices on calcium carbonate mineralization were studied. The results showed that both WSM and ASM of lapillus could mediate aragonite crystallization, but the size and morphology of the formed crystals were different. The WSM and ASM of asteriscus adsorbed on the silicon substrate had little effect on calcium carbonate mineralization; almost all the crystals were calcite, while both asteriscus WSM and ASM in solution could mediate vaterite crystals, and the morphologies of vaterite crystal aggregates were different.

  16. Effects of functional groups and soluble matrices in fish otolith on calcium carbonate mineralization

    International Nuclear Information System (INIS)

    Ren Dongni; Li Zhuo; Gao Yonghua; Feng Qingling

    2010-01-01

    Calcium carbonate mineralization is significantly influenced by organic matrices in vivo. The effect mainly relies on functional groups in proteins. In order to study the influence of functional groups on calcium carbonate mineralization, -OH, -NH 2 and -COOH groups were grafted onto single crystal silicon chips, and such modified chips were used as substrates in in vitro mineralization experiments. An x-ray photoelectron spectroscopy (XPS) test was conducted to examine the grafting efficiency, and the three groups were successfully grafted. Calcium carbonate mineralization on a modified silicon substrate was examined by a scanning electron microscope (SEM) and x-ray diffraction (XRD), and the results showed that the effects of -OH, -NH 2 and -COOH groups were quite different. Furthermore, a water-soluble protein matrix (WSM) and an acid-soluble protein matrix (ASM) extracted from fish otolith were adsorbed onto the -COOH-modified silicon substrate, and the effects of the protein matrices on calcium carbonate mineralization were studied. The results showed that both WSM and ASM of lapillus could mediate aragonite crystallization, but the size and morphology of the formed crystals were different. The WSM and ASM of asteriscus adsorbed on the silicon substrate had little effect on calcium carbonate mineralization; almost all the crystals were calcite, while both asteriscus WSM and ASM in solution could mediate vaterite crystals, and the morphologies of vaterite crystal aggregates were different.

  17. Effects of functional groups and soluble matrices in fish otolith on calcium carbonate mineralization.

    Science.gov (United States)

    Ren, Dongni; Li, Zhuo; Gao, Yonghua; Feng, Qingling

    2010-10-01

    Calcium carbonate mineralization is significantly influenced by organic matrices in vivo. The effect mainly relies on functional groups in proteins. In order to study the influence of functional groups on calcium carbonate mineralization, -OH, -NH2 and -COOH groups were grafted onto single crystal silicon chips, and such modified chips were used as substrates in in vitro mineralization experiments. An x-ray photoelectron spectroscopy (XPS) test was conducted to examine the grafting efficiency, and the three groups were successfully grafted. Calcium carbonate mineralization on a modified silicon substrate was examined by a scanning electron microscope (SEM) and x-ray diffraction (XRD), and the results showed that the effects of -OH, -NH2 and -COOH groups were quite different. Furthermore, a water-soluble protein matrix (WSM) and an acid-soluble protein matrix (ASM) extracted from fish otolith were adsorbed onto the -COOH-modified silicon substrate, and the effects of the protein matrices on calcium carbonate mineralization were studied. The results showed that both WSM and ASM of lapillus could mediate aragonite crystallization, but the size and morphology of the formed crystals were different. The WSM and ASM of asteriscus adsorbed on the silicon substrate had little effect on calcium carbonate mineralization; almost all the crystals were calcite, while both asteriscus WSM and ASM in solution could mediate vaterite crystals, and the morphologies of vaterite crystal aggregates were different.

  18. Minerals

    Science.gov (United States)

    ... Aren't minerals something you find in the earth, like iron and quartz? Well, yes, but small ... canned salmon and sardines with bones leafy green vegetables, such as broccoli calcium-fortified foods — from orange ...

  19. Serpentinization and its implications for life on the early Earth and Mars.

    Science.gov (United States)

    Schulte, Mitch; Blake, David; Hoehler, Tori; McCollom, Thomas

    2006-04-01

    Ophiolites, sections of ocean crust tectonically displaced onto land, offer significant potential to support chemolithoautotrophic life through the provision of energy and reducing power during aqueous alteration of their highly reduced mineralogies. There is substantial chemical disequilibrium between the primary olivine and pyroxene mineralogy of these ophiolites and the fluids circulating through them. This disequilibrium represents a potential source of chemical energy that could sustain life. Moreover, E (h)-pH conditions resulting from rock- water interactions in ultrabasic rocks are conducive to important abiotic processes antecedent to the origin of life. Serpentinization--the reaction of olivine- and pyroxene-rich rocks with water--produces magnetite, hydroxide, and serpentine minerals, and liberates molecular hydrogen, a source of energy and electrons that can be readily utilized by a broad array of chemosynthetic organisms. These systems are viewed as important analogs for potential early ecosystems on both Earth and Mars, where highly reducing mineralogy was likely widespread in an undifferentiated crust. Secondary phases precipitated during serpentinization have the capability to preserve organic or mineral biosignatures. We describe the petrology and mineral chemistry of an ophiolite-hosted cold spring in northern California and propose criteria to aid in the identification of serpentinizing terranes on Mars that have the potential to harbor chemosynthetic life.

  20. Biofilm formation and potential for iron cycling in serpentinization-influenced groundwater of the Zambales and Coast Range ophiolites.

    Science.gov (United States)

    Meyer-Dombard, D'Arcy R; Casar, Caitlin P; Simon, Alexander G; Cardace, Dawn; Schrenk, Matthew O; Arcilla, Carlo A

    2018-05-01

    Terrestrial serpentinizing systems harbor microbial subsurface life. Passive or active microbially mediated iron transformations at alkaline conditions in deep biosphere serpentinizing ecosystems are understudied. We explore these processes in the Zambales (Philippines) and Coast Range (CA, USA) ophiolites, and associated surface ecosystems by probing the relevance of samples acquired at the surface to in situ, subsurface ecosystems, and the nature of microbe-mineral associations in the subsurface. In this pilot study, we use microcosm experiments and batch culturing directed at iron redox transformations to confirm thermodynamically based predictions that iron transformations may be important in subsurface serpentinizing ecosystems. Biofilms formed on rock cores from the Zambales ophiolite on surface and in-pit associations, confirming that organisms from serpentinizing systems can form biofilms in subsurface environments. Analysis by XPS and FTIR confirmed that enrichment culturing utilizing ferric iron growth substrates produced reduced, magnetic solids containing siderite, spinels, and FeO minerals. Microcosms and enrichment cultures supported organisms whose near relatives participate in iron redox transformations. Further, a potential 'principal' microbial community common to solid samples in serpentinizing systems was identified. These results indicate collectively that iron redox transformations should be more thoroughly and universally considered when assessing the function of terrestrial subsurface ecosystems driven by serpentinization.

  1. Biological role in the transformation of platinum-group mineral grains

    Science.gov (United States)

    Reith, Frank; Zammit, Carla M.; Shar, Sahar S.; Etschmann, Barbara; Bottrill, Ralph; Southam, Gordon; Ta, Christine; Kilburn, Matthew; Oberthür, Thomas; Ball, Andrew S.; Brugger, Joël

    2016-04-01

    Platinum-group elements are strategically important metals. Finding new deposits is becoming increasingly difficult owing to our limited understanding of the processes that affect their mobility in surface environments. Microorganisms have been shown to promote the mobility of metals around ore deposits. Here we show that microorganisms influence the mobility of platinum-group elements in mineral grains collected from Brazil, Australia and Colombia. Scanning electron microscopy showed biofilms covering the platinum-group mineral grains. The biofilms contained abundant platinum-group element nanoparticles and microcrystalline aggregates, and were dominated by Proteobacteria, many of which were closely related to known metal-resistant species. Some platinum-group mineral grains contained carbon, nitrogen, sulfur, selenium and iodine, suggesting the grains may be biogenic in origin. Molecular analyses show that Brazilian platinum-palladium grains hosted specific bacterial communities, which were different in composition from communities associated with gold grains, or communities in surrounding soils and sediments. Nano-phase metallic platinum accumulated when a metallophillic bacterium was incubated with a percolating platinum-containing medium, suggesting that biofilms can cause the precipitation of mobile platinum complexes. We conclude that biofilms are capable of forming or transforming platinum-group mineral grains, and may play an important role for platinum-group element dispersion and re-concentration in surface environments.

  2. Minerals

    Directory of Open Access Journals (Sweden)

    Vaquero, M. P.

    1998-08-01

    Full Text Available The possible changes in the mineral composition of food during frying could be the consequence of losses by leaching, or changes in concentrations caused by exchanges between the food and culinary fat of other compounds. The net result depends on the type of food, the frying fat used and the frying process. Moreover, the modifications that frying produces in other nutrients could indirectly affect the availability of dietary minerals. The most outstanding ones are those that can take place in the fat or in the protein. With respect to the interactions between frying oils and minerals, we have recent knowledge concerning the effects of consuming vegetable oils used in repeated fryings of potatoes without turnover, on the nutritive utilization of dietary minerals. The experiments have been carried out in pregnant and growing rats, which consumed diets containing, as a sole source of fat, the testing frying oils or unused oils. It seems that the consumption of various frying oils, with a polar compound content lower or close to the maximum limit of 25% accepted for human consumption, does not alter the absorption and metabolism of calcium, phosphorous, iron or copper. Magnesium absorption from diets containing frying oils tends to increase but the urinary excretion of this element increases, resulting imperceptible the variations in the magnesium balance. The urinary excretion of Zn also increased although its balance remained unchanged. Different studies referring to the effects of consuming fried fatty fish on mineral bioavailability will also be presented. On one hand, frying can cause structural changes in fish protein, which are associated with an increase in iron absorption and a decrease in body zinc retention. The nutritive utilization of other elements such as magnesium, calcium and copper seems to be unaffected. On the other hand; it has been described that an excess of fish fatty acids in the diet produces iron depletion, but when fatty

  3. Exploration of the Role of Heat Activation in Enhancing Serpentine Carbon Sequestration Reactions

    International Nuclear Information System (INIS)

    McKelvy, M.J.; Chizmeshya, A.V.G.; Diefenbacher, J.; Bearat, H.; Wolf, G.

    2005-01-01

    As compared with other candidate carbon sequestration technologies, mineral carbonation offers the unique advantage of permanent disposal via geologically stable and environmentally benign carbonates. The primary challenge is the development of an economically viable process. Enhancing feedstock carbonation reactivity is key. Heat activation dramatically enhances aqueous serpentine carbonation reactivity. Although the present process is too expensive to implement, the materials characteristics and mechanisms that enhance carbonation are of keen interest for further reducing cost. Simultaneous thermogravimetric and differential thermal analysis (TGA/DTA) of the serpentine mineral lizardite was used to isolate a series of heat-activated materials as a function of residual hydroxide content at progressively higher temperatures. Their structure and composition are evaluated via TGA/DTA, X-ray powder diffraction (including phase analysis), and infrared analysis. The meta-serpentine materials that were observed to form ranged from those with longer range ordering, consistent with diffuse stage-2 like interlamellar order, to an amorphous component that preferentially forms at higher temperatures. The aqueous carbonation reaction process was investigated for representative materials via in situ synchrotron X-ray diffraction. Magnesite was observed to form directly at 15 MPa CO 2 and at temperatures ranging from 100 to 125 C. Carbonation reactivity is generally correlated with the extent of meta-serpentine formation and structural disorder.

  4. Serpentinization and the Formation of H2 and CH4 on Celestial Bodies (Planets, Moons, Comets).

    Science.gov (United States)

    Holm, N G; Oze, C; Mousis, O; Waite, J H; Guilbert-Lepoutre, A

    2015-07-01

    Serpentinization involves the hydrolysis and transformation of primary ferromagnesian minerals such as olivine ((Mg,Fe)2SiO4) and pyroxenes ((Mg,Fe)SiO3) to produce H2-rich fluids and a variety of secondary minerals over a wide range of environmental conditions. The continual and elevated production of H2 is capable of reducing carbon, thus initiating an inorganic pathway to produce organic compounds. The production of H2 and H2-dependent CH4 in serpentinization systems has received significant interdisciplinary interest, especially with regard to the abiotic synthesis of organic compounds and the origins and maintenance of life in Earth's lithosphere and elsewhere in the Universe. Here, serpentinization with an emphasis on the formation of H2 and CH4 are reviewed within the context of the mineralogy, temperature/pressure, and fluid/gas chemistry present in planetary environments. Whether deep in Earth's interior or in Kuiper Belt Objects in space, serpentinization is a feasible process to invoke as a means of producing astrobiologically indispensable H2 capable of reducing carbon to organic compounds.

  5. Mineralizations of the Lavalleja Group (Uruguay), a Probable Neoproterozoic Volcano-sedimentary Sequence

    International Nuclear Information System (INIS)

    Sanchez Bettucci, L.; Oyhantcabal, P.; Loureiro, J.; Basei, M.; Ramos, V.; Preciozzi, F.; Basei, M.

    2004-01-01

    The Lavalleja Group is located in the southern extreme of the Dom Feliciano Belt, being tentatively correlated with the Porongos and Brusque Groups of Brazil. The basement of the Lavalleja Group is probably represented by granitic gneissic rocks of the Campanero Unit with ages, in the southern portion, ranging from 1.75 to 2.1 Ga (U-Pb in zircon). The Lavalleja Group is characterized by narrow bands of meta sedimentary and meta volcanic rocks and it is separated in three formations, namely (from base to top): Zanja del Tigre, Fuente del Puma and Minas. Outcrops assigned to the Minas Formation have been recently correlated with the Arroyo del Soldado Group. Only the Fuente del Puma formation hosts base metals, Au and Ag occurrences. The Fuente del Puma formation is divided into three informal units: sedimentary, volcanic and hornblenditic gabbros. The sedimentary unit is characterized by an important amount of carbonates. Syn collisional to pos tectonic granitic bodies (Carapé Complex) intrudes the Lavalleja Group and the Campanero Unit. Several mineralizations are located in the Fuente del Puma Formation, those associated to Arrospide, Ramallo-Reus, Chape, Valencia, La Oriental, Apolonia, Redondo Hill, La China and La Paloma mines are the most important. In addition, many occurrences of Cu-Zn-Pb were recognized in the region. The Cu-Zn-Pb mineralization includes massive sulfides with pyrite-chalcopyrite-sphalerite-galena-pyrrothyte, arsenopyrite-hematite into small bodies with lenticular shape. The host rock shows frequently hydrothermal alteration. The geochemistry and the geological features of the mineralizations suggest Besshi Massive Sulphide Zn-Cu-Pb and SEDEX Zn-Pb as most probably genetic models for the deposits related to the Neoproterozoic orogeny. Early mineralizations are syngenetic and were formed on the sea floor, although the main mineralizations are related to remobilization during syn- to late-metamorphic events and thrusting

  6. Manganiferous minerals of the epidote group from the Archaean basement of West Greenland

    DEFF Research Database (Denmark)

    Katerinopoulou, Anna; Balic Zunic, Tonci; Kolb, Jochen

    2014-01-01

    The chemical compositions and crystal structures of Mn3+-containing minerals from the epidote group in Greenland rocks are investigated and described in detail. They occur in hydrothermally altered Archaean mafic sequences within the gneissic complex of the North Atlantic craton of West Greenland...

  7. 77 FR 22622 - AP Henderson Group, BPO Management Services, Inc., Capital Mineral Investors, Inc...

    Science.gov (United States)

    2012-04-16

    ... SECURITIES AND EXCHANGE COMMISSION [File No. 500-1] AP Henderson Group, BPO Management Services, Inc., Capital Mineral Investors, Inc., CardioVascular BioTherapeutics, Inc., and 1st Centennial... that there is a lack of current and accurate information concerning the securities of 1st Centennial...

  8. Stable isotope compositions of serpentinite seamounts in the Mariana forearc: Serpentinization processes, fluid sources and sulfur metasomatism

    Science.gov (United States)

    Alt, J.C.; Shanks, Wayne C.

    2006-01-01

    The Mariana and Izu-Bonin arcs in the western Pacific are characterized by serpentinite seamounts in the forearc that provide unique windows into the mantle wedge. We present stable isotope (O, H, S, and C) data for serpentinites from Conical seamount in the Mariana forearc and S isotope data for Torishima seamount in the Izu-Bonin forearc in order to understand the compositions of fluids and temperatures of serpentinization in the mantle wedge, and to investigate the transport of sulfur from the slab to the mantle wedge. Six serpentine mineral separates have a restricted range of ??18O (6.5-8.5???). Antigorite separates have ??D values of -29.5??? to -45.5??? that reflect serpentinization within the mantle wedge whereas chrysotile has low ??D values (-51.8??? to -84.0???) as the result of re-equilibration with fluids at low temperatures. Fractionation of oxygen isotopes between serpentine and magnetite indicate serpentinization temperatures of 300-375 ??C. Two late cross-fiber chrysotile veins have higher ??18O values of 8.9??? to 10.8??? and formed at lower temperatures (as low as ???100 ??C). Aqueous fluids in equilibrium with serpentine at 300-375 ??C had ??18O = 6.5-9??? and ??D = -4??? to -26???, consistent with sediment dehydration reactions at temperatures arc lavas. ?? 2006 Elsevier B.V. All rights reserved.

  9. Evolução geoquímica e mineralógica em perfis de alteração sobre rochas serpentinizadas no sudoeste de Minas Gerais Geochemical and mineralogical evolution in alteration profiles on serpentinized rocks in southwestern Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Pablo Vidal-Torrado

    2007-10-01

    Full Text Available Estudou-se a evolução geoquímica e mineralógica em três perfis distintos de alteração de rochas serpentinizadas que ocorrem nas imediações dos municípios de Alpinópolis e Fortaleza de Minas, no sudoeste do Estado de Minas Gerais, sob regimes de umidade e de temperatura údico e térmico, respectivamente. Nas condições atuais, o grau de evolução química e mineralógica é moderado em relação ao desenvolvido sobre outros tipos de rochas básicas e ultrabásicas da mesma área, caracterizando-se por uma importante perda de Na e Mg e, em menor proporção, de Ca e Si. O Al (localmente também o Fe é o elemento menos móvel dos sistemas. O K é escasso no material de origem e nas zonas de alteração, e ocorre enriquecimento desse elemento nos horizontes superficiais por aporte externo. Os minerais primários mais facilmente intemperizáveis, como o talco, a tremolita e a clorita trioctaédrica, são abundantes ainda na fração argila desses solos tropicais com composição mineralógica pouco comum, mas são todos termodinamicamente instáveis. Do ponto de vista geoquímico, o processo de alteração atual pode ser definido como uma bissialitização, que pode coincidir com ferruginização, com formação de minerais trioctaédricos secundários por transformação direta de estrutura e também por neoformação, todos coexistindo com os minerais primários residuais. No entanto, as fases de maior evolução, em volumes com drenagem mais eficiente, tendem à monossialitização, com formação de caulinitas de diferentes graus de cristalinidade. A assembléia mineralógica existente evidencia a metaestabilidade e o caráter incipiente do sistema pedogenético.The geochemical and mineralogical evolution was studied in three different alteration profiles of ultramafic (serpentine rocks near Alpinópolis and Fortaleza de Minas, in southwestern Minas Gerais State (Brazil. Soil moisture and temperature regimes are udic and thermic

  10. Serpentinization and alteration in an olivine cumulate from the Stillwater Complex, Southwestern Montana

    Science.gov (United States)

    Page, N.J.

    1976-01-01

    Some of the olivine cumulates of the Ultramafic zone of the Stillwater Complex, Montana, are progressively altered to serpentine minerals and thompsonite. Lizardite and chrysotile developed in the cumulus olivine and postcumulus pyroxenes; thompsonite developed in postcumulus plagioclase. The detailed mineralogy, petrology, and chemistry indicate that olivine and plagioclase react to form the alteration products, except for H2O, without changes in the bulk composition of the rocks. ?? 1976 Springer-Verlag.

  11. Crystal structure of ilyukhinite, a new mineral of the eudialyte group

    Energy Technology Data Exchange (ETDEWEB)

    Rastsvetaeva, R. K., E-mail: rast@crys.ras.ru; Rozenberg, K. A. [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Crystallography and Photonics Federal Scientific Research Center (Russian Federation); Chukanov, N. V. [Russian Academy of Sciences, Institute of Problems of Chemical Physics (Russian Federation); Aksenov, S. M. [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Crystallography and Photonics Federal Scientific Research Center (Russian Federation)

    2017-01-15

    The crystal structure of ilyukhinite, a new mineral of the eudialyte group, is studied by X-ray diffraction. The mineral found in pegmatite bodies of the Kukisvumchorr Mountain (Khibiny alkaline complex) is characterized by low sodium content, high degree of hydration, and predominance of manganese over iron. The trigonal cell has the following parameters: a = 14.1695(6) and c = 31.026(1) Å; space group R3m. The structure is refined to final R = 0.046 in the anisotropic approximation of atomic displacements using 1527F > 3σF. The idealized formula of ilyukhinite (Z = 3) is written as (H{sub 3}O,Na){sub 14}Ca{sub 6}Mn{sub 2}Zr{sub 3}Si{sub 26}O{sub 72}(OH){sub 2} · 3H{sub 2}O. The new mineral differs from other representatives of the eudialyte group by the predominance of both oxonium in the N positions of extra-framework cations and manganese in the Ðœ2 position centering the tetragonal pyramid.

  12. The XPS study of physical and chemical forms of neptunium group on the surface of minerals

    Directory of Open Access Journals (Sweden)

    Teterin Anton Yu.

    2010-01-01

    Full Text Available The sorption behavior and the physical and chemical forms of neptunium on the surface of minerals of the two chlorate samples, biotite and kaolin, with different contents of Fe(II was studied. The liquid-liquid extraction and the X-ray photoelectron spectroscopy were employed to identify the valence forms of neptunium. On the basis of the obtained data the quantitative elemental composition of the surface of the studied minerals, as well as the ionic composition of the formed neptunium complexes was determined. It was shown that the Np(IV and Np(VI containing compounds did not form, while the complexes Np(VO+ -hydroxyl did form on the surface. The oxygen ions bonded with iron and oxygen belonging to water and/or of carboxyl were suggested to be present in the equatorial plane of the neptunyl group NpO+.

  13. The mortality experience of a group of Newfoundland fluorspar miners exposed to Rn progeny

    International Nuclear Information System (INIS)

    Morrison, H.; Semenciw, R.; Mao, Y.; Wigle, D.

    1988-02-01

    A cohort study of the mortality experience (1950-1984) of 1,772 Newfoundland fluorspar miners occupationally exposed to high levels of radon daughters has been conducted using two control groups (surface workers and Newfoundland males). Observed numbers of cancers of the lung, salivary gland and buccal cavity/pharynx were significantly elevated among underground miners. A highly significant relationship was noted between radon daughter exposure and risk of dying of lung cancer; the small numbers of salivary gland (n = 2) and buccal cavity/pharynx cancers (n = 6) precluded meaningful analysis of dose-response. Also significantly elevated among underground miners were deaths from silicosis and pneumoconioses. No statistically significant excess was found for any cause of death among surface workers. Using external controls, attributable and relative risk coefficients for lung cancer were estimated as 6.3 per working level month per million person-years and 0.89 percent per working level month respectively. Attributable risk coefficients were similar to some, but not all related mining studies. Relative risk coefficients were highest for those first exposed attributable risks to non-smokers. Relative risks fell sharply with age at observation whereas attributable risks were lowest in the youngest and oldest age groups. Using the risk coefficients from the present study, a miner exposed for 30 years at 4 WLM per year from age 20 has a risk of 7,366 per 100,000 of dying of lung cancer by age 70 using the relative risk model and a risk of 6,371 per 100,000 using the attributable risk model. This compares to 3,740 per 100,000 for a non-exposed male. 85 refs

  14. A stable isotope study of serpentinization in the Fengtien ophiolite, Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Tzen-Fu Yui; Hsueh-Wen Yeh (Univ. of Hawaii, Honolulu (USA)); Chihming Wang Lee (National Taiwan Univ. (Taiwan))

    1990-05-01

    Detailed H- and O-isotopic studies of serpentinites of Fengtien ophiolite have been made in order to enhance our knowledge on the process of serpentinization. Pseudomorphic lizardites have {delta}{sup 18}O = +3.6{per thousand} and {delta}D = {minus}48 to {minus}49{per thousand}; bladed-mat and foliated antigorites have {delta}{sup 18}O = +3.5 to +5.8{per thousand} and {delta}D = {minus}45 to {minus}69{per thousand}; slickensided antigorites have {delta}{sup 18}O = +4.1 to +4.9{per thousand} and {delta}D = {minus}46 to {minus}50{per thousand}; picrolites have {delta}{sup 18}O = +4.2 to +4.3{per thousand} and {delta}D = {minus}65 to {minus}67{per thousand}; and slickensided chrysotiles have {delta}{sup 18}O = +4.1 to +4.5{per thousand} and {delta}D = {minus}80{per thousand}. It is suggested that lizardite might have formed in an oceanic environment, whereas antigorite and chrysotile have formed in continental environments. These results depict complicated multiple serpentinization processes. Isotopic temperatures calculated using {delta}{sup 18}O values of coexisting fissure-filling minerals range from 325 to 370{degree}C, which are consistent with those derived from phase equilibria involving serpentines. The narrow range of {delta}{sup 18}O and wide range of {delta}D values for antigorite and chrysotile also demonstrate that water/rock ratios during these serpentinizations should not have been high. These Fengtien serpentines fall outside either of the continental domains described by Wenner and Taylor (1973, 1974); and fall within their oceanic domain. We suggest that the domains proposed by Wenner and Taylor (1973, 1974) should be extended and that the terms, especially the continental antigorite and the continental lizardite-chrysotile, should be purely occurrence-descriptive.

  15. Heavy Metal Resistant, Alkalitolerant Bacteria Isolated From Serpentinizing Springs in the Zambales Ophiolite, Philippines

    Science.gov (United States)

    Vallalar, B.; Meyer-Dombard, D. R.; Cardace, D.; Arcilla, C. A.

    2016-12-01

    Serpentinization involves hydrologic alteration of ultramafic mantle rocks containing olivine and pyroxene to produce serpentine minerals. The fluids resulting from this reaction are reduced, extremely depleted in dissolved inorganic carbon, and are highly alkaline with pH values typically exceeding 10. Major byproducts of the serpentinizing reaction include iron oxides, hydrogen, methane, and small amounts of organic molecules that provide chemosynthetic energy for subsurface microbial communities. In addition, weathering of serpentine rocks often produces fluids and sediments that have elevated concentrations of various toxic heavy metals such as chromium, nickel, cobalt, copper, and zinc. Thus, microorganisms inhabiting these unique ecological niches must be adapted to a variety of physicochemical extremes. The purpose of this study is to isolate bacteria that are capable of withstanding extremely high concentrations of multiple heavy metals from serpentine fluid-associated sediments. Fluid and sediment samples for microbial culturing were collected from Manleluag Spring National Park located on the island of Luzon, Philippines. The area is part of the Zambales ophiolite range, and hosts several serpentinizing fluid seeps. Fluid emanating from the source pool of the spring, designated Manleluag 2 (ML2), has a pH of 10.83 and temperature of 34.4 °C. Luria-Bertani agar medium was supplemented with varying concentrations of five trace elements - Cu, Cr, Co, Ni, and Zn. Environmental samples were spread on each of these media and colony forming units were subsequently chosen for isolation. In all, over 20 isolates were obtained from media with concentrations ranging from 25 mg/L - 400 mg/L of each metal. Taxonomic identity of each isolate was determined using 16S rRNA gene sequences. The isolates were then tested for tolerance to alkaline conditions by altering LB medium to pH values of 8, 9, 10, 11, and 12. The majority of strains exhibit growth at the highest p

  16. Sulfur in serpentinized oceanic peridotites: Serpentinization processes and microbial sulfate reduction

    Science.gov (United States)

    Alt, J.C.; Shanks, Wayne C.

    1998-01-01

    The mineralogy, contents, and isotopic compositions of sulfur in oceanic serpentinites reflect variations in temperatures and fluid fluxes. Serpentinization of serpentinization of Iberian Margin peridotites occurred at low temperatures (???20??-200??C) and high water/rock ratios. Complete serpentinization and consumption of ferrous iron allowed evolution to higher fO2. Microbial reduction of seawater sulfate resulted in addition of low-??34S sulfide (-15 to -43???) and formation of higher-sulfur assemblages that include valleriite and pyrite. The high SO4/total S ratio of Hess Deep serpentinites (0.89) results in an increase of total sulfur and high ??34S of total sulfur (mean ??? 8???). In contrast, Iberian Margin serpentinites gained large amounts of 34S-poor sulfide (mean total S = 3800 ppm), and the high sulfide/total S ratio (0.61) results in a net decrease in ??34S of total sulfur (mean ??? -5???). Thus serpentinization is a net sink for seawater sulfur, but the amount fixed and its isotopic composition vary significantly. Serpentinization may result in uptake of 0.4-14 ?? 1012 g S yr-1 from the oceans, comparable to isotopic exchange in mafic rocks of seafloor hydrothermal systems and approaching global fluxes of riverine sulfate input and sedimentary sulfide output.

  17. CURRENT BUILDUP IN EMERGING SERPENTINE FLUX TUBES

    International Nuclear Information System (INIS)

    Pariat, E.; Masson, S.; Aulanier, G.

    2009-01-01

    The increase of magnetic flux in the solar atmosphere during active-region formation involves the transport of the magnetic field from the solar convection zone through the lowest layers of the solar atmosphere, through which the plasma β changes from >1 to <1 with altitude. The crossing of this magnetic transition zone requires the magnetic field to adopt a serpentine shape also known as the sea-serpent topology. In the frame of the resistive flux-emergence model, the rising of the magnetic flux is believed to be dynamically driven by a succession of magnetic reconnections which are commonly observed in emerging flux regions as Ellerman bombs. Using a data-driven, three-dimensional (3D) magnetohydrodynamic numerical simulation of flux emergence occurring in active region 10191 on 2002 November 16-17, we study the development of 3D electric current sheets. We show that these currents buildup along the 3D serpentine magnetic-field structure as a result of photospheric diverging horizontal line-tied motions that emulate the observed photospheric evolution. We observe that reconnection can not only develop following a pinching evolution of the serpentine field line, as usually assumed in two-dimensional geometry, but can also result from 3D shearing deformation of the magnetic structure. In addition, we report for the first time on the observation in the UV domain with the Transition Region and Coronal Explorer (TRACE) of extremely transient loop-like features, appearing within the emerging flux domain, which link several Ellermam bombs with one another. We argue that these loop transients can be explained as a consequence of the currents that build up along the serpentine magnetic field.

  18. Iron transformations during low temperature alteration of variably serpentinized rocks from the Samail ophiolite, Oman

    Science.gov (United States)

    Mayhew, Lisa E.; Ellison, Eric T.; Miller, Hannah M.; Kelemen, Peter B.; Templeton, Alexis S.

    2018-02-01

    Partially serpentinized peridotites in the Samail ophiolite in the Sultanate of Oman currently undergo low temperature alteration and hydration both at shallow levels, with water recently in contact with the atmosphere, and at depth, with anoxic, reducing fluids. However, it is unclear how changes in the distribution and oxidation state of Fe are driving the production of energy-rich gases such as hydrogen and methane detected in peridotite catchments. We track the Fe transformations in a suite of outcrop samples representing a subset of the spectrum of least to most altered end-members of the Oman peridotites. We use microscale mineralogical and geochemical analyses including QEMSCAN, Raman spectroscopy, synchrotron radiation X-ray fluorescence (XRF) mapping, and electron microprobe wavelength dispersive spectroscopy. The less-altered peridotites possess a diversity of Fe-bearing phases including relict primary minerals (e.g. olivine, pyroxene, chromite) and secondary phases (e.g. serpentine and brucite). Raman spectroscopy and electron microprobe data (Si/(Mg + Fe)) indicate that much of the serpentine is significantly intergrown with brucite on the sub-micron scale. These data also indicate that the Fe content of the brucite ranges from 10 to 20 wt% FeO. The mineral assemblage of the highly reacted rocks is less diverse, dominated by serpentine and carbonate while olivine and brucite are absent. Magnetite is relatively rare and mainly associated with chromite. Goethite and hematite, both Fe(III)-hydroxides, were also identified in the highly altered rocks. Whole rock chemical analyses reflect these mineralogical differences and show that Fe in the partially serpentinized samples is on average more reduced (∼0.40-0.55 Fe3+/FeTotal) than Fe in the highly reacted rocks (∼0.85-0.90 Fe3+/FeTotal). We propose that olivine, brucite, chromite and, perhaps, serpentine in the less-altered peridotites act as reactive phases during low temperature alteration of the Oman

  19. Geology and associated mineral occurrences of the Araxa Group, Mossamedes Region, Goias, Brazil

    International Nuclear Information System (INIS)

    Simoes, L.S.A.

    1984-01-01

    In the region of Mossamedes, State of Goias, Brazil, the Precambrian metamorphic rocks of the Araxa group were mapped at the scale of 1:25,000, with emphasis on stratigraphic, structural, petrographic and economic aspects. These metamorphites represent a continous stratigraphic sequence which, from bottom to top can be subdivided into five informal lithostratigraphic units: 1) psamitic unit (quartzite, metaconglomerate); 2) psamitic-pelitic unit (quartzite, quartz schist, muscovite schist); 3) lower pelitic - volcanic unit (chlorite - biotite schist, fine grained blastoporphyritic gneiss, amphibolite and calc-schist); 4) upper pelitic - volcanic unit (garnet muscovite schist, biotite schist and gneiss, amphibolite, magnetite muscovite schist); 5) gneissic unit (epidote biotite gneiss, amphibolite). Three types of meta-intrusive rocks were found, besides basic dykes related to Mesozoic magmatism. Four phases of deformation affected the volcano-sedimentary sequence;D 1 , D 2 , D 3 and D 4 , each of them developing distinct deformational features. Barrowian type metamorphism increases progressively from North to South from the biotite zone to the garnet zone (greenschist facies), reaching the staurolite-kyanite zone (amphibolite facies). The magmatism throughout the Group's evolution consists of mafic to felsic volcanic activity, mustly intermediary, as well as three intrusive events. Gold, copper and zinc minerals of economic interest occur within the studied area. The gold mineralizations are related to the pelitic-volcanic sequences. Copper occurs in several rocks from the pelitic-volcanic and gneissic sequences. (Author) [pt

  20. Effect of water activity on rates of serpentinization of olivine.

    Science.gov (United States)

    Lamadrid, Hector M; Rimstidt, J Donald; Schwarzenbach, Esther M; Klein, Frieder; Ulrich, Sarah; Dolocan, Andrei; Bodnar, Robert J

    2017-07-14

    The hydrothermal alteration of mantle rocks (referred to as serpentinization) occurs in submarine environments extending from mid-ocean ridges to subduction zones. Serpentinization affects the physical and chemical properties of oceanic lithosphere, represents one of the major mechanisms driving mass exchange between the mantle and the Earth's surface, and is central to current origin of life hypotheses as well as the search for microbial life on the icy moons of Jupiter and Saturn. In spite of increasing interest in the serpentinization process by researchers in diverse fields, the rates of serpentinization and the controlling factors are poorly understood. Here we use a novel in situ experimental method involving olivine micro-reactors and show that the rate of serpentinization is strongly controlled by the salinity (water activity) of the reacting fluid and demonstrate that the rate of serpentinization of olivine slows down as salinity increases and H 2 O activity decreases.

  1. Effect of water activity on rates of serpentinization of olivine

    Science.gov (United States)

    Lamadrid, Hector M.; Rimstidt, J. Donald; Schwarzenbach, Esther M.; Klein, Frieder; Ulrich, Sarah; Dolocan, Andrei; Bodnar, Robert J.

    2017-07-01

    The hydrothermal alteration of mantle rocks (referred to as serpentinization) occurs in submarine environments extending from mid-ocean ridges to subduction zones. Serpentinization affects the physical and chemical properties of oceanic lithosphere, represents one of the major mechanisms driving mass exchange between the mantle and the Earth's surface, and is central to current origin of life hypotheses as well as the search for microbial life on the icy moons of Jupiter and Saturn. In spite of increasing interest in the serpentinization process by researchers in diverse fields, the rates of serpentinization and the controlling factors are poorly understood. Here we use a novel in situ experimental method involving olivine micro-reactors and show that the rate of serpentinization is strongly controlled by the salinity (water activity) of the reacting fluid and demonstrate that the rate of serpentinization of olivine slows down as salinity increases and H2O activity decreases.

  2. Multiple Comparison of Age Groups in Bone Mineral Density under Heteroscedasticity

    Directory of Open Access Journals (Sweden)

    Ahmet Sezer

    2015-01-01

    Full Text Available Osteoporosis is a silent disease because individuals may not know that they have osteoporosis until their bones become so fragile. Bone mineral density (BMD test helps to detect osteoporosis and determine the risk fractures. This study covers bone measurement data from total body dual energy X-ray absorptiometry scans for 28,454 persons who participated in the 1996–2006 National Health and Nutrition Examination Survey in USA Dual energy X-ray absorptiometry (DXA method is known as the primary method for detecting osteoporosis because of its high precision and accuracy. Testing the equality of the means of normal populations when the variances are unknown and unequal is a fundamental problem in clinical trials and biomedical research. In this study we compare age groups based upon BMD in case of unequal variance being present among the groups. First we test equality of variances among the age groups by the Hartley test. And then Scott-Smith test is used to test equality of BMD means for the age groups. Finally, Tukey-Cramer confidence intervals are constructed to detect which groups start to differ from the reference group in which BMD reaches the peak level.

  3. Crystal structure of bassetite and saleeite. New insight into autunite-group minerals

    Energy Technology Data Exchange (ETDEWEB)

    Dal Bo, Fabrice; Hatert, Frederic [Liege Univ. (Belgium). Lab. de Mineralogie; Mees, Florias [Royal Museum for Central Africa, Tervuren (Belgium); Philippo, Simon [Musee National d' Histoire Naturelle, Luxembourg (Luxembourg). Section Mineralogie; Baijot, Maxime; Fontaine, Francois [Liege Univ. (Belgium). Dept. de Geologie

    2016-06-15

    The crystal structures of two autunite-group minerals have been solved recently. The crystal structure of bassetite, Fe{sup 2+}[(UO{sub 2})(PO{sub 4})]{sub 2}(H{sub 2}O){sub 10}, from the type locality in Cornwall, United Kingdom (Basset Mines) was solved for the first time. Bassetite is monoclinic, space group P2{sub 1}/n, a = 6.961(1), b = 20.039(2), c = 6.974(1) Aa and β = 90.46(1) . The crystal structure of saleeite, Mg[(UO{sub 2})(PO{sub 4})]{sub 2}(H{sub 2}O){sub 10}, from Shinkolobwe, Democratic Republic of Congo, was also solved. Saleeite is monoclinic, space group P2{sub 1}/n, a = 6.951(1), b = 19.942(1), c = 6.967(1) Aa and β = 90.58(1) . The crystal structure investigation of bassetite (R{sub 1} = 0.0658 for 1879 observed reflections with vertical stroke F{sub o} vertical stroke ≥ 4σ{sub F}) and saleeite (R{sub 1} = 0.0307 for 1990 observed reflections with vertical stroke F{sub o} vertical stroke ≥ 4σ{sub F}) confirms that both minerals are topologically identical and that bassetite contains ten water molecules per formula unit. Their structure contains autunite-type sheets, [(UO{sub 2})(PO{sub 4})]{sup -}, consisting of corner-sharing UO{sub 6} square bipyramids and PO{sub 4} tetrahedra. Iron and magnesium are surrounded by water molecules to form Fe(H{sub 2}O){sub 6} or Mg(H{sub 2}O){sub 6} octahedra located in interlayer, between the autunite-type sheets. Two isolated independent water molecules are also located in interlayer. Energy-dispersive X-ray spectroscopy analysis confirmed the chemical composition obtained from structure refinement. These new data prompt a re-assessment of minerals of the autunite and meta-autunite groups.

  4. Carbon dioxide sequestration by direct mineral carbonation with carbonic acid

    Energy Technology Data Exchange (ETDEWEB)

    O' Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P.; Turner, Paul C.

    2000-01-01

    conditions, have achieved roughly 83% conversion of heat treated serpentine and 84% conversion of olivine to the carbonate in 6 hours. The results from the current studies suggest that reaction kinetics can be improved by pretreatment of the mineral, catalysis of the reaction, or some combination of the two. Future tests are intended to examine a broader pressure/temperature regime, various pretreatment options, as well as other mineral groups.

  5. Carbon dioxide sequestration by direct mineral carbonation with carbonic acid

    Energy Technology Data Exchange (ETDEWEB)

    O' Connor, W.K.; Dahlin, D.C.; Nilsen, D.N.; Walters, R.P.; Turner, P.C.

    2000-07-01

    The Albany Research Center (ARC) of the US Department of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite and member (mg{sub 2}SiO{sub 4})], or serpentine [Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}]. This slurry is reacted with supercritical carbon dioxide (CO{sub 2}) to produce magnesite (MgCO{sub 3}). The CO{sub 2} is dissolved in water to form carbonic acid (H{sub 2}CO{sub 3}), which dissociates to H{sup +} and HCO{sub 3}{sup {minus}}. The H{sup +} reacts with the mineral, liberating Mg{sup 2+} cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO{sub 2} pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185 C and a partial pressure of CO{sub 2} (P{sub CO{sub 2}}) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction conditions, have achieved roughly 83% conversion of heat treated serpentine

  6. Characterization of serpentine. A potential nuclear shielding material

    International Nuclear Information System (INIS)

    Sengupta, A.; Rajeswari, B.; Kadam, R.M.; Kshirsagar, R.J.

    2012-01-01

    The use of serpentine as a potential nuclear shielding material necessitates a chemical quality control of the samples before its use in reactors. With this in view, characterization of these mineral samples was carried out using inductively coupled plasma atomic emission spectrometry (ICP-AES) and Instrumental neutron activation analysis (INAA) methods. The analytical results obtained by both ICP-AES and NAA techniques were found to be comparable. Na, Cr, Co, Zn, and Cu were found to be present in all samples of Indian origin while Ga, Ag, Ni, and Cd were found to below the limits of detection. A comparison on the detection limits of elements of interest was also carried out by both the analytical techniques and found to be in good agreement. An infrared spectroscopic investigation was also carried out on all the mineral samples. Bands at 3,689 and 3,648 cm -1 were attributed to inner and outer hydroxyl stretching of Mg-OH, respectively. The weak and broad band centered around 3,416 cm -1 was assigned due to the stretching vibrations of the adsorbed water molecules while three bands at 1076, 1022 and 968 cm -1 were prescribed to the vibrations of the SiO 4 tetrahedra. (author)

  7. Late Byzantine mineral soda high alumina glasses from Asia Minor: a new primary glass production group.

    Directory of Open Access Journals (Sweden)

    Nadine Schibille

    Full Text Available The chemical characterisation of archaeological glass allows the discrimination between different glass groups and the identification of raw materials and technological traditions of their production. Several lines of evidence point towards the large-scale production of first millennium CE glass in a limited number of glass making factories from a mixture of Egyptian mineral soda and a locally available silica source. Fundamental changes in the manufacturing processes occurred from the eight/ninth century CE onwards, when Egyptian mineral soda was gradually replaced by soda-rich plant ash in Egypt as well as the Islamic Middle East. In order to elucidate the supply and consumption of glass during this transitional period, 31 glass samples from the assemblage found at Pergamon (Turkey that date to the fourth to fourteenth centuries CE were analysed by electron microprobe analysis (EPMA and by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS. The statistical evaluation of the data revealed that the Byzantine glasses from Pergamon represent at least three different glass production technologies, one of which had not previously been recognised in the glass making traditions of the Mediterranean. While the chemical characteristics of the late antique and early medieval fragments confirm the current model of glass production and distribution at the time, the elemental make-up of the majority of the eighth- to fourteenth-century glasses from Pergamon indicate the existence of a late Byzantine glass type that is characterised by high alumina levels. Judging from the trace element patterns and elevated boron and lithium concentrations, these glasses were produced with a mineral soda different to the Egyptian natron from the Wadi Natrun, suggesting a possible regional Byzantine primary glass production in Asia Minor.

  8. SERPENTINE COIL TOPOLOGY FOR BNL DIRECT WIND SUPERCONDUCTING MAGNETS

    International Nuclear Information System (INIS)

    PARKER, B.; ESCALLIER, J.

    2005-01-01

    Serpentine winding, a recent innovation developed at BNL for direct winding superconducting magnets, allows winding a coil layer of arbitrary multipolarity in one continuous winding process and greatly simplifies magnet design and production compared to the planar patterns used before. Serpentine windings were used for the BEPC-II Upgrade and JPARC magnets and are proposed to make compact final focus magnets for the EC. Serpentine patterns exhibit a direct connection between 2D body harmonics and harmonics derived from the integral fields. Straightforward 2D optimization yields good integral field quality with uniformly spaced (natural) coil ends. This and other surprising features of Serpentine windings are addressed in this paper

  9. Prediction of Gibbs energies of formation and stability constants of some secondary uranium minerals containing the uranyl group

    International Nuclear Information System (INIS)

    Genderen, A.C.G. van; Weijden, C.H. van der

    1984-01-01

    For a group of minerals containing a common anion there exists a linear relationship between two parameters called ΔO and ΔF.ΔO is defined as the difference between the Gibbs energy of formation of a solid oxide and the Gibbs energy of formation of its aqueous cation, while ΔF is defined as the Gibbs energy of reaction of the formation of a mineral from the constituting oxide(s) and the acid. Using the Gibbs energies of formation of a number of known minerals the corresponding ΔO's and ΔF's were calculated and with the resulting regression equation it is possible to predict values for the Gibbs energies of formation of other minerals containing the same anion. This was done for 29 minerals containing the uranyl-ion together with phosphate, vanadate, arsenate or carbonate. (orig.)

  10. Compositional Evolution of Pyrochlore-Group Minerals in Carbonatites of the Belaya Zima Pluton, Eastern Sayan

    Science.gov (United States)

    Khromova, E. A.; Doroshkevich, A. G.; Sharygin, V. V.; Izbrodin, L. A.

    2017-12-01

    Pyrochlore-group minerals are the main concentrators of niobium in carbonatites of the Belaya Zima alkaline pluton. Fluorcalciopyrochlore, kenopyrochlore and hydropyrochlore were identified in chemical composition. Their main characteristics are given: compositional variation, morphology, and zoning. During evolution from early calcite to late ankerite carbonatites, the UO2, TiO2, REE, and Y contents gradually increased. All carbonatite types are suggested to contain initial fluorcalciopyrochlore. However, in calcite-dolomite and ankerite carbonatites, it is partially or completely hydrated due to hydrothermal processes at the late stage of the pluton. This hydration resulted in the appearance of kenopyrochlore and hydropyrochlore due to removal of Ca, Na and F, and input of Ba, H2O, K, Si, Fe, and probably U and REE. At the last stage of the pluton, this hydrated pyrochlore was replaced by Fe-bearing columbite.

  11. Large-Scale Deformation and Uplift Associated with Serpentinization

    Science.gov (United States)

    Germanovich, L. N.; Lowell, R. P.; Smith, J. E.

    2014-12-01

    Geologic and geophysical data suggest that partially serpentinized peridotites and serpentinites are a significant part of the oceanic lithosphere. All serpentinization reactions are exothermic and result in volume expansion as high as 40%. Volume expansion beneath the seafloor will lead to surface uplift and elevated stresses in the neighborhood of the region undergoing serpentinization. The serpentinization-induced stresses are likely to result in faulting or tensile fracturing that promote the serpentinization process by creating new permeability and allowing fluid access to fresh peridotite. To explore these issues, we developed a first-order model of crustal deformation by considering an inclusion undergoing transformation strain in an elastic half-space. Using solutions for inclusions of different shapes, orientations, and depths, we calculate the surface uplift and mechanical stresses generated by the serpentinization processes. We discuss the topographic features at the TAG hydrothermal field (Mid-Atlantic Ridge, 26°N), uplift of the Miyazaki Plain (Southwestern Japan), and tectonic history of the Atlantic Massif (inside corner high of the Mid-Atlantic Ridge, 30°N, and the Atlantis Transform Fault). Our analysis suggests that an anomalous salient of 3 km in diameter and 100 m high at TAG may have resulted from approximately 20% transformational strain in a region beneath the footwall of the TAG detachment fault. This serpentinization process tends to promote slip along some overlying normal faults, which may then enhance fluid pathways to the deeper crust to continue the serpentinization process. The serpentinization also favors slip and seismicity along the antithetic faults identified below the TAG detachment fault. Our solution for the Miyazaki Plain above the Kyushu-Palau subduction zone explains the observed uplift of 120 m, but the transformational strain needs only be 3%. Transformational strains associated with serpentinization in this region may

  12. The serpentine mitral valve and cerebral embolism

    Directory of Open Access Journals (Sweden)

    Ker James

    2011-02-01

    Full Text Available Abstract Valvular strands, well-delineated filiform masses, attached to cardiac valve edges are associated with cerebral embolism and stroke. Strokes, caused by emboli from valvular strands, tend to occur among younger persons. In this case report a valvular strand, giving a peculiar serpentine appearance to the mitral valve is described. This mitral valvular strand was the only explanation for an episode of cerebral embolism, presenting with a transient right sided hemiparesis. It is proposed that a randomized study involving combined treatment with aspirin and clopidogrel is warranted in young patients with valvular strands, presenting with a first episode of cerebral embolism.

  13. Platinum-group elements and gold in base metal sulfides, platinum-group minerals, and Re-Os isotope compositions of the Uitkomst complex, South Africa

    Czech Academy of Sciences Publication Activity Database

    Trubač, Jakub; Ackerman, Lukáš; Gauert, Ch.; Ďurišová, Jana; Hrstka, Tomáš

    2018-01-01

    Roč. 113, č. 2 (2018), s. 439-461 ISSN 0361-0128 R&D Projects: GA ČR GA13-15390S Institutional support: RVO:67985831 Keywords : binary alloys * copper compounds * economic geology * gold * iridium * isotopes * ore deposits * osmium * palladium * platinum * platinum metals * pyrites * Rhenium * rhenium alloys * ruthenium * solid solutions * sulfur compounds * crustal materials * mass-balance calculations * massive sulfides * mineralized zone * monosulfide solid solutions * platinum group elements * platinum group elements (PGEs) * platinum group minerals Subject RIV: DB - Geology ; Mineralogy; AC - Archeology, Anthropology, Ethnology (ARUB-Q) OBOR OECD: Geology; Archaeology (ARUB-Q) Impact factor: 2.519, year: 2016

  14. Acidic surface functional groups and mineral elements in Lakra coal (Sindh, Pakistan)

    International Nuclear Information System (INIS)

    Saeed, K.; Ishaq, M.; Ahjmad, I.; Shakirullah, M.; Haider, S.

    2010-01-01

    Surface acidity of virgin coal (Lakra Sindh, Pakistan) and variously extracted/leached coal samples with HNO/sub 3/ NaOH, and KMnO/sub 4/, were investigated by aqueous potentiometric titration employing KOH as a titrant. The titration curve of virgin coal showed that its surface might contain carboxylic, carbonyl, phenolic and other weak acidic functional groups such as enols and C-H bond. The titration curves of leached coal samples showed inflections at pH 4-11, being not similar the inflections of carboxylic groups. This inflection might be given by functional groups like CO/sub 2/, phenolic, enols and C-H. Mineral matter such as Fe, K, Zn, Mn and Ni were determined in the ash of coal by atomic absorption spectrophotometer and was found that Fe (3104 micro g/g) in the highest and Ni (36.05 micro g/g) in the lowest quantity is present in virgin coal sample. (author)

  15. Competitive platinum-group-metal (PGM) supply from the Eastern Limb, Bushveld Complex: Geological, mining and mineral economic aspects

    CSIR Research Space (South Africa)

    McGill, JE

    2011-08-01

    Full Text Available -GROUP-METAL (PGM) SUPPLY FROM THE EASTERN LIMB, BUSHVELD COMPLEX: GEOLOGICAL, MINING, AND MINERAL ECONOMIC ASPECTS Dr. Jeannette E. McGill & Prof. Murray W. Hitzman ACKNOWLEDGEMENTS ? COUNCIL FOR SCIENTIFIC AND INDUSTRIAL RESEARCH (CSIR) ? Centre for Mining... Innovation ? Office of Graduate Studies, Fogarty Endowment ? Mr. VISHNU PILLAY (EXECUTIVE HEAD: JV?S ? Anglo Platinum) ? ACADEMIC ADVISORS Prof. Murray Hitzman (Economic Geology); Dr. Hugh Miller (Mining Engineering); Prof. Rodderick Eggert (Mineral...

  16. Present day serpentinization in New Caledonia, Oman and Yugoslavia

    Science.gov (United States)

    Barnes, I.; O'Neil, J.R.; Trescases, J.J.

    1978-01-01

    Geochemical evidence for modern low-temperature serpentinization has been found in three new localities. Apparently the low-temperature reactions are a common mode of formation of the lizardite-chrysotile and brucite assemblage. Possibly the 18O content of serpentine formed at low temperatures is in part inherited from the pyroxene and olivine. ?? 1978.

  17. Quantifying Cr(VI) Production and Export from Serpentine Soil of the California Coast Range.

    Science.gov (United States)

    McClain, Cynthia N; Fendorf, Scott; Webb, Samuel M; Maher, Kate

    2017-01-03

    Hexavalent chromium (Cr(VI)) is generated in serpentine soils and exported to surface and groundwaters at levels above health-based drinking water standards. Although Cr(VI) concentrations are elevated in serpentine soil pore water, few studies have reported field evidence documenting Cr(VI) production rates and fluxes that govern Cr(VI) transport from soil to water sources. We report Cr speciation (i) in four serpentine soil depth profiles derived from the California Coast Range serpentinite belt and (ii) in local surface waters. Within soils, we detected Cr(VI) in the same horizons where Cr(III)-minerals are colocated with biogenic Mn(III/IV)-oxides, suggesting Cr(VI) generation through oxidation by Mn-oxides. Water-extractable Cr(VI) concentrations increase with depth constituting a 7.8 to 12 kg/km 2 reservoir of Cr(VI) in soil. Here, Cr(VI) is produced at a rate of 0.3 to 4.8 kg Cr(VI)/km 2 /yr and subsequently flushed from soil during water infiltration, exporting 0.01 to 3.9 kg Cr(VI)/km 2 /yr at concentrations ranging from 25 to 172 μg/L. Although soil-derived Cr(VI) is leached from soil at concentrations exceeding 10 μg/L, due to reduction and dilution during transport to streams, Cr(VI) levels measured in local surface waters largely remain below California's drinking water limit.

  18. Sedimentology and economic potential of a storm-derived heavy-mineral deposit in the Witteberg group, Cape Province

    Energy Technology Data Exchange (ETDEWEB)

    Cole, D I; Labuschagne, L S

    1982-06-01

    Two heavy-mineral-bearing, very fine-grained sandstone beds occur in the upper part of the Weltevrede Formation of the Witteberg Group, 35 km east-north-east of Willowmore, Cape Province. The beds are located within a 10-m-thick stratigraphic interval approximately 100 m below the base of the Witpoort Formation. The beds are amalgamated and consist of up to 5 units, each representing deposition from a storm-surge ebb current. Nine samples taken from the upper bed and one from the lower were analysed for heavy-mineral content. In order of decreasing abundance the heavy-minerals are rutile, zircon, ilmenite, magnetite, monazite, staurolite and sphene. The zircon contains uranium and the monazite is thorium bearing. Simple linear regression analysis of three elements, three oxides, the heavy mineral fraction and the radiometric response indicate that the proportion of heavy minerals does not vary significantly between samples and that the radiometric response of the beds (determined with a portable gamma-ray scintillometer) is directly related to the heavy mineral content. The heavy minerals are concentrated in the upper 20 cm of each bed where deposition from suspension, during the final phase of storm activity, was predominant. Significant concentrations are limited to the upper bed.

  19. Sedimentology and economic potential of a storm-derived heavy-mineral deposit in the Witteberg group, Cape Province

    International Nuclear Information System (INIS)

    Cole, D.I.; Labuschagne, L.S.

    1982-06-01

    Two heavy-mineral-bearing, very fine-grained sandstone beds occur in the upper part of the Weltevrede Formation of the Witteberg Group, 35 km east-north-east of Willowmore, Cape Province. The beds are located within a 10-m-thick stratigraphic interval approximately 100 m below the base of the Witpoort Formation. The beds are amalgamated and consist of up to 5 units, each representing deposition from a storm-surge ebb current. Nine samples taken from the upper bed and one from the lower were analysed for heavy-mineral content. In order of decreasing abundance the heavy-minerals are rutile, zircon, ilmenite, magnetite, monazite, staurolite and sphene. The zircon contains uranium and the monazite is thorium bearing. Simple linear regression analysis of three elements, three oxides, the heavy mineral fraction and the radiometric response indicate that the proportion of heavy minerals does not vary significantly between samples and that the radiometric response of the beds (determined with a portable gamma-ray scintillometer) is directly related to the heavy mineral content. The heavy minerals are concentrated in the upper 20 cm of each bed where deposition from suspension, during the final phase of storm activity, was predominant. Significant concentrations are limited to the upper bed

  20. Water removal characteristics of parallel serpentine channels

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, K.; Zhou, B.; Quan, P. [Windsor Univ., ON (Canada). Dept. of Mechanical, Automotive and Materials Engineering

    2005-07-01

    A study was conducted in which the liquid water behaviours in parallel serpentine channels with manifolds on the cathode side of a proton exchange membrane (PEM) fuel cell stack were examined. A 3-dimensional, unsteady two-phase flow model within the commercial computational fluid dynamics software package FLUENT was used. Membrane electrode assemblies (MEA) were placed on different sides in the numerical analysis. Several water management issues were identified for this type of fuel cell stack by examining the flow behaviours of liquid water and airflow velocity fields. It was shown that water in the outflow manifold could be blocked by air streams from the gas flow channels, with water flowing continuously into the outflow manifold. It was also shown that the pressure drop along all the unit cells can never increase or decrease at the same pace. Water which adheres to the end wall of both the inlet and outlet manifolds is difficult to remove. It was suggested that faster water drainage can be achieved by keeping the MEA side of the gas flow channels close to the outlet of the outflow manifold. It was also suggested that the collecting and separating effect at the serpentine gas flow channels could improve the water drainage. 8 refs., 10 figs.

  1. Carbonate control of H2 and CH4 production in serpentinization systems at elevated P-Ts

    Science.gov (United States)

    Jones, L. Camille; Rosenbauer, Robert; Goldsmith, Jonas I.; Oze, Christopher

    2010-01-01

    Serpentinization of forsteritic olivine results in the inorganic synthesis of molecular hydrogen (H2) in ultramafic hydrothermal systems (e.g., mid-ocean ridge and forearc environments). Inorganic carbon in those hydrothermal systems may react with H2 to produce methane (CH4) and other hydrocarbons or react with dissolved metal ions to form carbonate minerals. Here, we report serpentinization experiments at 200°C and 300 bar demonstrating Fe2+ being incorporated into carbonates more rapidly than Fe2+ oxidation (and concomitant H2 formation) leading to diminished yields of H2 and H2-dependent CH4. In addition, carbonate formation is temporally fast in carbonate oversaturated fluids. Our results demonstrate that carbonate chemistry ultimately modulates the abiotic synthesis of both H2 and CH4 in hydrothermal ultramafic systems and that ultramafic systems present great potential for CO2-mineral sequestration.

  2. New insight on Li and B isotope fractionation during serpentinization derived from batch reaction investigations

    Science.gov (United States)

    Hansen, Christian T.; Meixner, Anette; Kasemann, Simone A.; Bach, Wolfgang

    2017-11-01

    Multiple batch experiments (100 °C, 200 °C; 40 MPa) were conducted, using Dickson-type reactors, to investigate Li and B partitioning and isotope fractionation between rock and water during serpentinization. We reacted fresh olivine (5 g; Fo90; [B] = anti-correlated with temperature, we argue for an overall attenuation of the isotopic effect through changes in B speciation in saline solutions (NaB(OH)4(aq) and B(OH)3Cl-) as well as variable B fixation and fractionation for different serpentinization product minerals (brucite, chrysotile). Breakdown of the Li-rich olivine and limited Li incorporation into product mineral phases resulted in an overall lower Li content of the final solid phase assemblage at 200 °C ([Li]final_200 °C = 0.77 μg/g; DS/FLi200 °C = 1.58). First order changes in Li isotopic compositions were defined by mixing of two isotopically distinct sources i.e. the fresh olivine and the fluid rather than by equilibrium isotope fraction. At 200 °C primary olivine is dissolved, releasing its Li budget into the fluid which shifts towards a lower δ7LiF of +38.62‰. Newly formed serpentine minerals (δ7LiS = +30.58‰) incorporate fluid derived Li with a minor preference of the 6Li isotope. At 100 °C Li enrichment of secondary phases exceeded Li release by olivine breakdown ([Li]final_100 °C = 2.10 μg/g; DS/FLi100 °C = 11.3) and it was accompanied by preferential incorporation of heavier 7Li isotope that might be due to incorporation of a 7Li enriched fluid fraction into chrysotile nanotubes.

  3. Silicate geothermometry as an indicator of water-rock interaction processes in the serpentinized mafic-ultramafic intrusion of Ylivieska

    International Nuclear Information System (INIS)

    Ruskeeniemi, T.; Blomqvist, R.; Vuorela, P.; Frape, S.K.; Blyth, A.

    1996-01-01

    The aim of the study was to use oxygen and hydrogen isotopes to examine the origin of different generations of serpentine. Of special interest was the study of low-temperature generations that may be correlated with the present meteoric waters. The research was commenced with drill core logging in order to obtain insight into the fracture minerals and their distribution in a mafic-ultramafic intrusion. (39 refs., 17 figs., 5 tabs.)

  4. Gibbs Free Energy of Formation for Selected Platinum Group Minerals (PGM

    Directory of Open Access Journals (Sweden)

    Spiros Olivotos

    2016-01-01

    Full Text Available Thermodynamic data for platinum group (Os, Ir, Ru, Rh, Pd and Pt minerals are very limited. The present study is focused on the calculation of the Gibbs free energy of formation (ΔfG° for selected PGM occurring in layered intrusions and ophiolite complexes worldwide, applying available experimental data on their constituent elements at their standard state (ΔG = G(species − ΔG(elements, using the computer program HSC Chemistry software 6.0. The evaluation of the accuracy of the calculation method was made by the calculation of (ΔGf of rhodium sulfide phases. The calculated values were found to be ingood agreement with those measured in the binary system (Rh + S as a function of temperature by previous authors (Jacob and Gupta (2014. The calculated Gibbs free energy (ΔfG° followed the order RuS2 < (Ir,OsS2 < (Pt, PdS < (Pd, PtTe2, increasing from compatible to incompatible noble metals and from sulfides to tellurides.

  5. Rare and Endangered Geophyte Plant Species in Serpentine of Kosovo

    Directory of Open Access Journals (Sweden)

    Naim Berisha

    2014-12-01

    Full Text Available Our study documents information on rarity, geographical distribution, taxonomy and conservation status of 11 geophyte species in serpentine soils of Kosovo, already included in the Red Book of Vascular Flora of Kosovo. Kosovo’s serpentine vegetation represents a diversity that yet has not been sufficiently explored. Large serpentine complexes are found in the northern Kosovo but also southern part of the country is rich in serpentines, therefore in endemics. Serpentine rocks and soils are characterized by low level of principal plant nutrients (N, P, K, Ca and exceptionally high levels of Mg and Fe. Serpentines play particular importance for flora of the country due to their richness in endemic plant species. The following 11 plant species have been studied: Aristolochia merxmuelleri, Colchicum hungaricum, Crocus flavus, Crocus kosaninii, Epimedium alpinum, Gentiana punctata, Gladiolus illyricus, Lilium albanicum, Paeonia peregrina, Tulipa gesneriana and Tulipa kosovarica. Five out of eleven studied geophytes fall within Critically Endangered IUCN based threat category and five out of eleven are local endemics. Aristolochia merxmuelleri and Tulipa kosovarica are steno-endemic plant species that are found exclusively in serpentine soils. Information in our database should prove to be valuable to efforts in ecology, floristics, biosystematics, conservation and land management.

  6. Thermal activation of serpentine for adsorption of cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Chun-Yan [College of Land and Environment, Shenyang Agricultural University, Shenyang (China); College of Chemistry, Chemical Engineering and Food Safety, Bohai University, Jinzhou (China); Liang, Cheng-Hua, E-mail: liang110161@163.com [College of Land and Environment, Shenyang Agricultural University, Shenyang (China); Yin, Yan [Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang (China); Du, Li-Yu [College of Land and Environment, Shenyang Agricultural University, Shenyang (China)

    2017-05-05

    Highlights: • Thermal activated serpentine was prepared by changing heated temperature. • Thermal activated serpentine exhibited excellent adsorption behavior for cadmium. • The adsorption mechanisms could be explained as formation of CdCO{sub 3} and Cd(OH){sub 2}. • The adsorption obeyed Langmuir model and pseudo second order kinetics model. - Abstract: Thermal activated serpentine with high adsorption capacity for heavy metals was prepared. The batch experiment studies were conducted to evaluate the adsorption performance of Cd{sup 2+} in aqueous solution using thermal activated serpentine as adsorbent. These samples before and after adsorption were characterized by XRD, FT-IR, SEM, XPS, and N{sub 2} adsorption-desorption at low temperature. It was found that serpentine with layered structure transformed to forsterite with amorphous structure after thermal treatment at over 700 °C, while the surface area of the samples was increased with activated temperature and the serpentine activated at 700 °C (S-700) presented the largest surface area. The pH of solution after adsorption was increased in different degrees due to hydrolysis of MgO in serpentine, resulting in enhancing adsorption of Cd{sup 2+}. The S-700 exhibited the maximum equilibrium adsorption capacity (15.21 mg/g), which was 2 times more than pristine serpentine. Langmuir isotherm was proved to describe the equilibrium adsorption data better than Freundlich isotherm and pseudo second order kinetics model could fit the adsorption kinetics processes well. Based on the results of characterization with XPS and XRD, the adsorption mechanisms could be explained as primarily formation of CdCO{sub 3} and Cd(OH){sub 2} precipitation on the surface of serpentine.

  7. Thermal activation of serpentine for adsorption of cadmium

    International Nuclear Information System (INIS)

    Cao, Chun-Yan; Liang, Cheng-Hua; Yin, Yan; Du, Li-Yu

    2017-01-01

    Highlights: • Thermal activated serpentine was prepared by changing heated temperature. • Thermal activated serpentine exhibited excellent adsorption behavior for cadmium. • The adsorption mechanisms could be explained as formation of CdCO_3 and Cd(OH)_2. • The adsorption obeyed Langmuir model and pseudo second order kinetics model. - Abstract: Thermal activated serpentine with high adsorption capacity for heavy metals was prepared. The batch experiment studies were conducted to evaluate the adsorption performance of Cd"2"+ in aqueous solution using thermal activated serpentine as adsorbent. These samples before and after adsorption were characterized by XRD, FT-IR, SEM, XPS, and N_2 adsorption-desorption at low temperature. It was found that serpentine with layered structure transformed to forsterite with amorphous structure after thermal treatment at over 700 °C, while the surface area of the samples was increased with activated temperature and the serpentine activated at 700 °C (S-700) presented the largest surface area. The pH of solution after adsorption was increased in different degrees due to hydrolysis of MgO in serpentine, resulting in enhancing adsorption of Cd"2"+. The S-700 exhibited the maximum equilibrium adsorption capacity (15.21 mg/g), which was 2 times more than pristine serpentine. Langmuir isotherm was proved to describe the equilibrium adsorption data better than Freundlich isotherm and pseudo second order kinetics model could fit the adsorption kinetics processes well. Based on the results of characterization with XPS and XRD, the adsorption mechanisms could be explained as primarily formation of CdCO_3 and Cd(OH)_2 precipitation on the surface of serpentine.

  8. Chevkinite-group minerals from granulite-facies metamorphic rocks and associated pegmatites of East Antarctica and South India

    Science.gov (United States)

    Belkin, Harvey E.; Macdonald, R.; Grew, E.S.

    2009-01-01

    Electron microprobe data are presented for chevkinite-group minerals from granulite-facies rocks and associated pegmatites of the Napier Complex and Mawson Station charnockite in East Antarctica and from the Eastern Ghats, South India. Their compositions conform to the general formula for this group, viz. A4BC2D2Si4O22 where, in the analysed specimens A = (rare-earth elements (REE), Ca, Y, Th), B = Fe2+, Mg, C = (Al, Mg, Ti, Fe2+, Fe3+, Zr) and D = Ti and plot within the perrierite field of the total Fe (as FeO) (wt.%) vs. CaO (wt.%) discriminator diagram of Macdonald and Belkin (2002). In contrast to most chevkinite-group minerals, the A site shows unusual enrichment in the MREE and HREE relative to the LREE and Ca. In one sample from the Napier Complex, Y is the dominant cation among the total REE + Y in the A site, the first reported case of Y-dominance in the chevkinite group. The minerals include the most Al-rich yet reported in the chevkinite group (≤9.15 wt.% Al2O3), sufficient to fill the C site in two samples. Conversely, the amount of Ti in these samples does not fill the D site, and, thus, some of the Al could be making up the deficiency at D, a situation not previously reported in the chevkinite group. Fe abundances are low, requiring Mg to occupy up to 45% of the B site. The chevkinite-group minerals analysed originated from three distinct parageneses: (1) pegmatites containing hornblende and orthopyroxene or garnet; (2) orthopyroxene-bearing gneiss and granulite; (3) highly aluminous paragneisses in which the associated minerals are relatively magnesian or aluminous. Chevkinite-group minerals from the first two parageneses have relatively high FeO content and low MgO and Al2O3 contents; their compositions plot in the field for mafic and intermediate igneous rocks. In contrast, chevkinite-group minerals from the third paragenesis are notably more aluminous and have greater Mg/Fe ratios

  9. Near-wall serpentine cooled turbine airfoil

    Science.gov (United States)

    Lee, Ching-Pang

    2013-09-17

    A serpentine coolant flow path (54A-54G) formed by inner walls (50, 52) in a cavity (49) between pressure and suction side walls (22, 24) of a turbine airfoil (20A). A coolant flow (58) enters (56) an end of the airfoil, flows into a span-wise channel (54A), then flows forward (54B) over the inner surface of the pressure side wall, then turns behind the leading edge (26), and flows back along a forward part of the suction side wall, then follows a loop (54E) forward and back around an inner wall (52), then flows along an intermediate part of the suction side wall, then flows into an aft channel (54G) between the pressure and suction side walls, then exits the trailing edge (28). This provides cooling matched to the heating topography of the airfoil, minimizes differential thermal expansion, revives the coolant, and minimizes the flow volume needed.

  10. Eudialyte-group minerals from the Monte de Trigo alkaline suite, Brazil: composition and petrological implications

    Directory of Open Access Journals (Sweden)

    Gaston Eduardo Enrich Rojas

    Full Text Available ABSTRACT: The Monte de Trigo alkaline suite is a SiO2-undersaturated syenite-gabbroid association from the Serra do Mar alkaline province. Eudialyte-group minerals (EGMs occur in one nepheline microsyenite dyke, associated with aegirine-augite, wöhlerite, låvenite, magnetite, zircon, titanite, britholite, and pyrochlore. Major compositional variations include Si (25.09- 25.57 apfu , Nb (0.31- 0.76 apfu , Fe (1.40-2.13 apfu , and Mn (1.36- 2.08 apfu . The EGMs also contain relatively high contents of Ca (6.13- 7.10 apfu , moderate enrichment of rare earth elements (0.38-0.67 apfu , and a relatively low Na content (11.02-12.28 apfu , which can be correlated with their transitional agpaitic assemblage. EGM compositions indicate a complex solid solution that includes eudialyte, kentbrooksite, feklichevite, zirsilite-(Ce, georgbarsanovite, and manganoeudialyte components. EGM trace element analyses show low Sr and Ba contents and a negative Eu/Eu* anomaly, which are interpreted as characteristic of the parental magma due to the previous fractionation of plagioclase and/or alkali feldspar. The EGMs from the dyke border have higher contents of Fe, Sr (2,161-2,699 ppm, Mg (1,179-3,582 ppm, and Zn (732- 852 ppm than those at the dyke center. These differences are related to the incorporation of xenoliths and xenocrysts of melatheralitic host rock into the nepheline-syenitic magma followed by crystal-melt diffusive exchange.

  11. Metamorphic assemblages and the direction of flow of metamorphic fluids in four instances of serpentinization

    Science.gov (United States)

    Barnes, I.; Rapp, J.B.; O'Neil, J.R.; Sheppard, R.A.; Gude, A.J.

    1972-01-01

    Fluids related to Serpentinization are of at least three types. The first reported (Barnes and O'Neil, 1969) is a fluid of local meteoric origin, the chemical and thermodynamic properties of which are entirely controlled by olivine, orthopyroxene, brucite, and serpentine reactions. It is a Ca+2-OH-1 type and is shown experimentally to be capable of reacting with albite to yield calcium hydroxy silicates. Rodingites may form where the Ca+2-OH-1 type waters flow across the ultramafic contact and react with siliceous country rock. The second type of fluid has its chemical composition largely controlled before it enters the ultramafic rocks, but reactions within the ultramafic rocks fix the thermodynamic properties by reactions of orthopyroxene, olivine, calcite, brucite, and serpentine. The precipitation of brucite from this fluid clearly shows that fluid flow allows reaction products to be deposited at a distance from the point of solution. Thus, textural evidence for volume relations during Serpentinization may not be valid. The third type of fluid has its chemical properties fixed in part before the reactions with ultramafic rocks, in part by the reactions of orthopyroxene, olivine, and serpentine and in part by reactions with siliceous country rock at the contact. The reactions of the ultramafic rock and country rock with the fluid must be contemporaneous and require flow to be along the contact. This third type of fluid is grossly supersaturated with talc and tremolite, both found along the contact. The occurrence of magadiite, kenyaite, mountainite, and rhodesite along the contact is probably due to a late stage low-temperature reaction of fluids of the same thermodynamic properties as those that formed the talc and tremolite at higher temperatures. Oxygen isotope analyses of some of these minerals supports this conclusion. Rodingites form from Ca+2-rich fluids flowing across the contact; talc and tremolite form from silica-rich fluids flowing along the contact

  12. A shallow marine storm-induced heavy-mineral deposit in the Witteberg group near Willomore, Cape Province

    International Nuclear Information System (INIS)

    Cole, D.I.; Labuschagne, L.S.

    1982-01-01

    Two heavy-mineral-bearing sandstone beds were discovered within the Weltevrede Formation of the Witteberg Group during a routine investigation of an aerial radiometric survey. Maximum concentrations of 142 ppm U and 434 ppm Th were determined by x-ray fluorescence analysis. The sandstone beds that were investigated closely resemble amalgamated storm deposits, each unit representing the product of an individual storm. A radiometric survey indicated that the highest concentration of heavy-minerals are limited to the upper 20 cm of the main bed and the indicated resources are as follows: rutile - 2700 tons, zircon - 850 tons, ilmenite - 650 tons, magnetite - 550 tons, monozite - 200 tons, and uranium - 5 tons

  13. Mantle Serpentinization near the Central Mariana Trench Constrained by Ocean Bottom Surface Wave Observations

    Science.gov (United States)

    Cai, C.; Wiens, D. A.; Lizarralde, D.; Eimer, M. O.; Shen, W.

    2017-12-01

    We investigate the crustal and uppermost mantle seismic structure across the Mariana trench by jointly inverting Rayleigh wave phase and group velocities from ambient noise and longer period phase velocities from Helmholtz tomography of teleseismic waveforms. We use data from a temporary deployment in 2012-2013, consisting of 7 island-based stations and 20 broadband ocean bottom seismographs, as well as data from the USGS Northern Mariana Islands Seismograph Network. To avoid any potential bias from the starting model, we use a Bayesian Monte-Carlo algorithm to invert for the azimuthally-averaged SV-wave velocity at each node. This method also allows us to apply prior constraints on crustal thickness and other parameters in a systematic way, and to derive formal estimates of velocity uncertainty. The results show the development of a low velocity zone within the incoming plate beginning about 80 km seaward of the trench axis, consistent with the onset of bending faults from bathymetry and earthquake locations. The maximum depth of the velocity anomaly increases towards the trench, and extends to about 30 km below the seafloor. The low velocities persist after the plate is subducted, as a 20-30 km thick low velocity layer with a somewhat smaller velocity reduction is imaged along the top of the slab beneath the forearc. An extremely low velocity zone is observed beneath the serpentine seamounts in the outer forearc, consistent with 40% serpentinization in the forearc mantle wedge. Azimuthal anisotropy results show trench parallel fast axis within the incoming plate at uppermost mantle depth (2%-4% anisotropy). All these observations suggest the velocity reduction in the incoming plate prior to subduction results from both serpentinized normal faults and water-filled cracks. Water is expelled from the cracks early in subduction, causing a modest increase in the velocity of the subducting mantle, and moves upward and causes serpentinization of the outer forearc

  14. Serpentinization of abyssal peridotites from the MARK area, Mid-Atlantic Ridge: Sulfur geochemistry and reaction modeling

    Science.gov (United States)

    Alt, J.C.; Shanks, Wayne C.

    2003-01-01

    The opaque mineralogy and the contents and isotope compositions of sulfur in serpentinized peridotites from the MARK (Mid-Atlantic Ridge, Kane Fracture Zone) area were examined to understand the conditions of serpentinization and evaluate this process as a sink for seawater sulfur. The serpentinites contain a sulfur-rich secondary mineral assemblage and have high sulfur contents (up to 1 wt.%) and elevated ??34Ssulfide (3.7 to 12.7???). Geochemical reaction modeling indicates that seawater-peridotite interaction at 300 to 400??C alone cannot account for both the high sulfur contents and high ??34Ssulfide. These require a multistage reaction with leaching of sulfide from subjacent gabbro during higher temperature (???400??C) reactions with seawater and subsequent deposition of sulfide during serpentinization of peridotite at ???300??C. Serpentinization produces highly reducing conditions and significant amounts of H2 and results in the partial reduction of seawater carbonate to methane. The latter is documented by formation of carbonate veins enriched in 13C (up to 4.5???) at temperatures above 250??C. Although different processes produce variable sulfur isotope effects in other oceanic serpentinites, sulfur is consistently added to abyssal peridotites during serpentinization. Data for serpentinites drilled and dredged from oceanic crust and from ophiolites indicate that oceanic peridotites are a sink for up to 0.4 to 6.0 ?? 1012 g seawater S yr-1. This is comparable to sulfur exchange that occurs in hydrothermal systems in mafic oceanic crust at midocean ridges and on ridge flanks and amounts to 2 to 30% of the riverine sulfate source and sedimentary sulfide sink in the oceans. The high concentrations and modified isotope compositions of sulfur in serpentinites could be important for mantle metasomatism during subduction of crust generated at slow spreading rates. ?? 2003 Elsevier Science Ltd.

  15. A theoretical study of the fast-neutron attenuation in Ghanaian serpentine shields

    International Nuclear Information System (INIS)

    Akaho, E.H.K.; Anim-Sampong, S.

    1994-01-01

    Theoretical calculations were done to determine the suitability of local serpentine rocks for shielding fast neutrons. A coupled neutron-gamma library of 25 energy groups, IRAN3.LIB developed for ANISN/PC was used to generate nuclear data for the tested shields. Calculations were carried out assuming a P 3 scattering order for spherical geometry with S 6 angular quadrature. From the trends of attenuation and computer factors such as relaxation length and transmission there is the indication that the shielding properties of the local shields are better than the foreign serpentine shields used in this study. They are slightly inferior to ordinary concrete employed in shielding power reactors. (author). 9 refs.; 5 tabs.; 5 figs

  16. Evolution of fracture permeability of ultramafic rocks undergoing serpentinization at hydrothermal conditions: An experimental study

    Science.gov (United States)

    Farough, Aida; Moore, Diane E.; Lockner, David A.; Lowell, R.P.

    2016-01-01

    We performed flow-through laboratory experiments on five cylindrically cored samples of ultramafic rocks, in which we generated a well-mated through-going tensile fracture, to investigate evolution of fracture permeability during serpentinization. The samples were tested in a triaxial loading machine at a confining pressure of 50 MPa, pore pressure of 20 MPa, and temperature of 260°C, simulating a depth of 2 km under hydrostatic conditions. A pore pressure difference of up to 2 MPa was imposed across the ends of the sample. Fracture permeability decreased by 1–2 orders of magnitude during the 200–330 h experiments. Electron microprobe and SEM data indicated the formation of needle-shaped crystals of serpentine composition along the walls of the fracture, and chemical analyses of sampled pore fluids were consistent with dissolution of ferro-magnesian minerals. By comparing the difference between fracture permeability and matrix permeability measured on intact samples of the same rock types, we concluded that the contribution of the low matrix permeability to flow is negligible and essentially all of the flow is focused in the tensile fracture. The experimental results suggest that the fracture network in long-lived hydrothermal circulation systems can be sealed rapidly as a result of mineral precipitation, and generation of new permeability resulting from a combination of tectonic and crystallization-induced stresses is required to maintain fluid circulation.

  17. Stable isotope compositions of serpentinite seamounts in the Mariana forearc: Serpentinization processes, fluid sources and sulfur metasomatism

    Science.gov (United States)

    Alt, J.C.; Shanks, Wayne C.

    2006-01-01

    The Mariana and Izu-Bonin arcs in the western Pacific are characterized by serpentinite seamounts in the forearc that provide unique windows into the mantle wedge. We present stable isotope (O, H, S, and C) data for serpentinites from Conical seamount in the Mariana forearc and S isotope data for Torishima seamount in the Izu-Bonin forearc in order to understand the compositions of fluids and temperatures of serpentinization in the mantle wedge, and to investigate the transport of sulfur from the slab to the mantle wedge. Six serpentine mineral separates have a restricted range of ??18O (6.5-8.5???). Antigorite separates have ??D values of -29.5??? to -45.5??? that reflect serpentinization within the mantle wedge whereas chrysotile has low ??D values (-51.8??? to -84.0???) as the result of re-equilibration with fluids at low temperatures. Fractionation of oxygen isotopes between serpentine and magnetite indicate serpentinization temperatures of 300-375 ??C. Two late cross-fiber chrysotile veins have higher ??18O values of 8.9??? to 10.8??? and formed at lower temperatures (as low as ???100 ??C). Aqueous fluids in equilibrium with serpentine at 300-375 ??C had ??18O = 6.5-9??? and ??D = -4??? to -26???, consistent with sediment dehydration reactions at temperatures aragonite veins in metabasalt and siltstone clasts within the serpentinite flows have ??18O = 16.7-24.5???, consistent with the serpentinizing fluids at temperatures <250 ??C. ??13C values of 0.1-2.5??? suggest a source in subducting carbonate sediments. The ??34S values of sulfide in serpentinites on Conical Seamount (-6.7??? to 9.8???) result from metasomatism through variable reduction of aqueous sulfate (??34S = 14???) derived from slab sediments. Despite sulfur metasomatism, serpentinites have low sulfur contents (generally < 164 ppm) that reflect the highly depleted nature of the mantle wedge. The serpentinites are mostly enriched in 34S (median ??34Ssulfide = 4.5???), consistent with a 34S

  18. The diesel exhaust in miners study: II. Exposure monitoring surveys and development of exposure groups.

    NARCIS (Netherlands)

    Coble, J.B.; Stewart, P.A.; Vermeulen, R.; Yereb, D.; Stanevich, R.; Blair, A.; Silverman, D.T.; Attfield, M.

    2010-01-01

    Air monitoring surveys were conducted between 1998 and 2001 at seven non-metal mining facilities to assess exposure to respirable elemental carbon (REC), a component of diesel exhaust (DE), for an epidemiologic study of miners exposed to DE. Personal exposure measurements were taken on workers in a

  19. Neutron activation analysis of minerals from Cuddapah basin geological formations

    International Nuclear Information System (INIS)

    Nagendra Kumar, P.V.; Suresh Kumar, N.; Acharya, R.; Reddy, A.V.R.; Krishna Reddy, L.

    2014-01-01

    Green and yellow serpentines along with two associated minerals namely dolomite and intrusive rock dolerite obtained from the asbestos mines of Cuddapah basin, Andhra Pradesh, India were analyzed by k 0 -based neutron activation analysis (k 0 -NAA) method. Gold ( 197 Au) was used as the single comparator. Two reference materials namely USGS W-1 (geological) and IAEA Soil-7 (environmental) were analyzed as control samples to evaluate the accuracy of the method. A total of 21 elements present at major, minor and trace concentrations were determined in serpentines as well as associated minerals. The elemental concentrations were used for distinguishing and characterizing these minerals, and also to understand the extent of segregation of elements from the associated or host mineral rocks to serpentines. (author)

  20. Unusual metabolic diversity of hyperalkaliphilic microbial communities associated with subterranean serpentinization at The Cedars.

    Science.gov (United States)

    Suzuki, Shino; Ishii, Shun'ichi; Hoshino, Tatsuhiko; Rietze, Amanda; Tenney, Aaron; Morrill, Penny L; Inagaki, Fumio; Kuenen, J Gijs; Nealson, Kenneth H

    2017-11-01

    Water from The Cedars springs that discharge from serpentinized ultramafic rocks feature highly basic (pH=~12), highly reducing (E h serpentinizing system, was dominated by several bacterial taxa from the phyla OD1 ('Parcubacteria') and Chloroflexi. Members of the GPS1 community had, for the most part, the smallest genomes reported for their respective taxa, and encoded only archaeal (A-type) ATP synthases or no ATP synthases at all. Furthermore, none of the members encoded respiration-related genes and some of the members also did not encode key biosynthesis-related genes. In contrast, BS5, fed by shallow water, appears to have a community driven by hydrogen metabolism and was dominated by a diverse group of Proteobacteria similar to those seen in many terrestrial serpentinization sites. Our findings indicated that the harsh ultrabasic geological setting supported unexpectedly diverse microbial metabolic strategies and that the deep-water-fed springs supported a community that was remarkable in its unusual metagenomic and genomic constitution.

  1. Modeling low-temperature serpentinization reactions to estimate molecular hydrogen production with implications for potential microbial life on Saturn's moon Enceladus.

    Science.gov (United States)

    Zwicker, Jennifer; Smrzka, Daniel; Taubner, Ruth-Sophie; Bach, Wolfgang; Rittmann, Simon; Schleper, Christa; Peckmann, Jörn

    2017-04-01

    Serpentinization of ultramafic rocks attracts much interest in research on the origin of life on Earth and the search for life on extraterrestrial bodies including icy moons like Enceladus. Serpentinization on Earth occurs in peridotite-hosted systems at slow-spreading mid-ocean ridges, and produces large amounts of molecular hydrogen and methane. These reduced compounds can be utilized by diverse chemosynthetic microbial consortia as a metabolic energy source. Although many hydrothermal vents emit hot and acidic fluids today, it is more likely that life originated in the Archean at sites producing much cooler and more alkaline fluids that allowed for the synthesis and stability of essential organic molecules necessary for life. Therefore, a detailed understanding of water-rock interaction processes during low-temperature serpentinization is of crucial importance in assessing the life-sustaining potential of these environments. In the course of serpentinization, the metasomatic hydration of olivine and pyroxene produces various minerals including serpentine minerals, magnetite, brucite, and carbonates. Hydrogen production only occurs if ferrous iron within iron-bearing minerals is oxidized and incorporated as ferric iron into magnetite. The PHREEQC code was used to model the pH- and temperature-dependent dissolution of olivine and pyroxene to form serpentine, magnetite and hydrogen under pressure and temperature conditions that may exist on Saturn's icy moon Enceladus. Various model setups at 25 and 50°C were run to assess the influence of environmental parameters on hydrogen production. The results reveal that hydrogen production rates depend on the composition of the initial mineral assemblage and temperature. The current assumption is that there is a gaseous phase between Enceladus' ice sheet and subsurface ocean. To test various scenarios, model runs were conducted with and without the presence of a gas phase. The model results show that hydrogen production is

  2. Management of chronic kidney disease–mineral and bone disorder: Korean working group recommendations

    Directory of Open Access Journals (Sweden)

    Eunah Hwang

    2015-03-01

    Full Text Available For Korean dialysis patients, chronic kidney disease–mineral bone disorder is a serious burden because of cardiovascular calcification and mortality. However, recent epidemiologic data have demonstrated that many patients undergoing maintenance hemodialysis are out of the target ranges of serum calcium, phosphorus, and intact parathyroid hormone. Thus, we felt the necessity for the development of practical recommendations to treat abnormal serum phosphorus, calcium, and iPTH in dialysis patients. In this paper, we briefly comment on the measurement of serum calcium, phosphorus, iPTH, dialysate calcium concentration, dietary phosphorus restriction, use of phosphate binders, and medical and surgical options to correct secondary hyperparathyroidism. In particular, for the optimal management of secondary hyperparathyroidism, we suggest a simplified medication adjustment according to certain ranges of serum phosphorus and calcium. Large-scale, well-designed clinical studies are required to support our strategies to control chronic kidney disease–mineral bone disorder in this country. Based on such data, our practice guidelines could be established and better long-term outcomes should be anticipated in our dialysis patients.

  3. Multistage crack seal vein and hydrothermal Ni enrichment in serpentinized ultramafic rocks (Koniambo massif, New Caledonia)

    Science.gov (United States)

    Cathelineau, Michel; Myagkiy, Andrey; Quesnel, Benoit; Boiron, Marie-Christine; Gautier, Pierre; Boulvais, Philippe; Ulrich, Marc; Truche, Laurent; Golfier, Fabrice; Drouillet, Maxime

    2017-10-01

    Sets of fractures and breccia sealed by Ni-rich silicates and quartz occur within saprock of the New Caledonian regolith developed over ultramafic rocks. The crystallization sequence in fractures is as follows: (1) serpentine stage: lizardite > polygonal serpentine > white lizardite; (2) Ni stage: Ni-Mg kerolite followed by red-brown microcrystalline quartz; and (3) supergene stages. The red-brown microcrystalline quartz corresponds to the very last stage of the Ni sequence and is inferred to have precipitated within the 50-95 °C temperature range. It constitutes also the main cement of breccia that has all the typical features of hydraulic fracturing. The whole sequence is therefore interpreted as the result of hydrothermal fluid circulation under medium to low temperature and fluctuating fluid pressure. Although frequently described as the result of a single downward redistribution of Ni and Mg leached in the upper part of the regolith under ambient temperature, the Ni silicate veins thus appear as the result of recurrent crack and seal process, corresponding to upward medium temperature fluid convection, hydraulic fracturing and subsequent fluid mixing, and mineral deposition.

  4. Reaction-induced fracturing during olivine serpentinization: A mechanistic investigation at the interface scale

    NARCIS (Netherlands)

    Plümper, O.; Røyne, A.; Malthe-Sørenssen, A.; King, H. E.; Jamtveit, B.

    Serpentinization of the Earth's impermeable upper mantle is one of the most fundamental metamorphic hydration reactions. It governs lithospheric weakening, geochemical subduction zone input and possibly even the formation of life-essential building blocks. Serpentinization relies on fluid pathway

  5. Orthogonally interdigitated shielded serpentine travelling wave cathode ray tube deflection structure

    Science.gov (United States)

    Hagen, E.C.; Hudson, C.L.

    1995-07-25

    A new deflection structure which deflects a beam of charged particles, such as an electron beam, includes a serpentine set for transmitting a deflection field, and a shielding frame for housing the serpentine set. The serpentine set includes a vertical serpentine deflection element and a horizontal serpentine deflection element. These deflection elements are identical, and are interdigitatedly and orthogonally disposed relative to each other, for forming a central transmission passage, through which the electron beam passes, and is deflected by the deflection field, so as to minimize drift space signal distortion. The shielding frame includes a plurality of ground blocks, and forms an internal serpentine trough within these ground blocks, for housing the serpentine set. The deflection structure further includes a plurality of feedthrough connectors which are inserted through the shielding frame, and which are electrically connected to the serpentine set. 10 figs.

  6. Deformation, Fluid Flow and Mantle Serpentinization at Oceanic Transform Faults

    Science.gov (United States)

    Rupke, L.; Hasenclever, J.

    2017-12-01

    Oceanic transform faults (OTF) and fracture zones have long been hypothesized to be sites of enhanced fluid flow and biogeochemical exchange. In this context, the serpentine forming interaction between seawater and cold lithospheric mantle rocks is particularly interesting. The transformation of peridotite to serpentinite not only leads to hydration of oceanic plates and is thereby an important agent of the geological water cycle, it is also a mechanism of abiotic hydrogen and methane formation, which can support archeal and bacterial communities at the seafloor. Inferring the likely amount of mantle undergoing serpentinization reactions therefore allows estimating the amount of biomass that may be autotrophically produced at and around oceanic transform faults and mid-ocean ridges Here we present results of 3-D geodynamic model simulations that explore the interrelations between deformation, fluid flow, and mantle serpentinization at oceanic transform faults. We investigate how slip rate and fault offset affect the predicted patterns of mantle serpentinization around oceanic transform faults. Global rates of mantle serpentinization and associated H2 production are calculated by integrating the modeling results with plate boundary data. The global additional OTF-related production of H2 is found to be between 6.1 and 10.7 x 1011 mol per year, which is comparable to the predicted background mid-ocean ridge rate of 4.1 - 15.0 x 1011 mol H2/yr. This points to oceanic transform faults as potential sites of intense fluid-rock interaction, where chemosynthetic life could be sustained by serpentinization reactions.

  7. Time-resolved x-ray diffraction analysis of the experimental dehydration of serpentine at high pressure

    International Nuclear Information System (INIS)

    Inoue, Toru; Yoshimi, Isamu; Yamada, Akihiro; Kikegawa, Takumi

    2009-01-01

    Time-resolved, in situ X-ray diffraction analysis was used to determine the dehydration rate and kinetics of serpentine during experimental dehydration at high pressures. The capsule used comprises a diamond sleeve fitted with Au or Pt lids in order to provide high-quality, time-resolved X-ray diffraction data. Antigorite quickly dehydrated to enstatite + forsterite + fluid within 2 h at 650degC below ∼6 GPa. Avrami modeling of the results and SEM observations of the partially dehydrated sample revealed that the nucleation rate was quite high for enstatite but low for forsterite, showing incubation periods of ∼10 min before appearing. The crystallization of these minerals is controlled largely by the composition of the fluid generated from serpentine dehydration. The dehydration boundary determined below 6 GPa in the present study is consistent with the results of previous phase equilibrium studies. This study indicates that serpentine in a subducting slab dehydrates rapidly below 6 GPa when the slab intersects the dehydration boundary conditions. (author)

  8. Serpentine concrete in the experiment and application of Tianwan nuclear power station

    International Nuclear Information System (INIS)

    Wang Kaihua; Qian Fuhua

    2015-01-01

    The choice of the configuration of the serpentine concrete aggregate is very important. From selection of serpentine concrete raw materials, and test and adjustment of mixture ratio, the paper elaborates in detail the special physical properties and engineering application, and provides detailed information for the promotion and application of the serpentine concrete. (authors)

  9. The application of artificial intelligence for the identification of the maceral groups and mineral components of coal

    Science.gov (United States)

    Mlynarczuk, Mariusz; Skiba, Marta

    2017-06-01

    The correct and consistent identification of the petrographic properties of coal is an important issue for researchers in the fields of mining and geology. As part of the study described in this paper, investigations concerning the application of artificial intelligence methods for the identification of the aforementioned characteristics were carried out. The methods in question were used to identify the maceral groups of coal, i.e. vitrinite, inertinite, and liptinite. Additionally, an attempt was made to identify some non-organic minerals. The analyses were performed using pattern recognition techniques (NN, kNN), as well as artificial neural network techniques (a multilayer perceptron - MLP). The classification process was carried out using microscopy images of polished sections of coals. A multidimensional feature space was defined, which made it possible to classify the discussed structures automatically, based on the methods of pattern recognition and algorithms of the artificial neural networks. Also, from the study we assessed the impact of the parameters for which the applied methods proved effective upon the final outcome of the classification procedure. The result of the analyses was a high percentage (over 97%) of correct classifications of maceral groups and mineral components. The paper discusses also an attempt to analyze particular macerals of the inertinite group. It was demonstrated that using artificial neural networks to this end makes it possible to classify the macerals properly in over 91% of cases. Thus, it was proved that artificial intelligence methods can be successfully applied for the identification of selected petrographic features of coal.

  10. GIS-based identification of areas with mineral resource potential for six selected deposit groups, Bureau of Land Management Central Yukon Planning Area, Alaska

    Science.gov (United States)

    Jones, James V.; Karl, Susan M.; Labay, Keith A.; Shew, Nora B.; Granitto, Matthew; Hayes, Timothy S.; Mauk, Jeffrey L.; Schmidt, Jeanine M.; Todd, Erin; Wang, Bronwen; Werdon, Melanie B.; Yager, Douglas B.

    2015-01-01

    This study, covering the Bureau of Land Management (BLM) Central Yukon Planning Area (CYPA), Alaska, was prepared to aid BLM mineral resource management planning. Estimated mineral resource potential and certainty are mapped for six selected mineral deposit groups: (1) rare earth element (REE) deposits associated with peralkaline to carbonatitic intrusive igneous rocks, (2) placer and paleoplacer gold, (3) platinum group element (PGE) deposits associated with mafic and ultramafic intrusive igneous rocks, (4) carbonate-hosted copper deposits, (5) sandstone uranium deposits, and (6) tin-tungsten-molybdenum-fluorspar deposits associated with specialized granites. These six deposit groups include most of the strategic and critical elements of greatest interest in current exploration.

  11. Characterization of Serpentine Samples from the Coast Range Ophiolite Microbial Observatory with μ-FTIR and XRD. ­­

    Science.gov (United States)

    Sousa, A.; Cardace, D.

    2017-12-01

    Serpentinizing systems hold much promise as potentially habitable environments in diverse planetary settings. They involve abundant and simple ingredients (i.e., the mineral olivine, liquid water), support subsurface microbial communities on Earth (Crespo-Medina et al. 2014; Suzuki et al. 2014; Kelley et al. 2005) and are thought to occur elsewhere in our solar system such as Mars (Schulte et al. 2006; Ehlmann et al. 2010)and possibly ocean worlds (Waite et al. 2017; Vance 2009). Although geochemical and microbial data collection continues in serpentinizing systems, the identification and resolution of potential biosignatures in serpentinites are not yet clear. Specifically, the micro-scale mineralogical contexts in which cell fragments or biofilm residues may be formed and preserved is lacking. Here we report preliminary transmission and reflection mode μ-FTIR spectral maps and XRD diffractograms, obtained with instruments relevant to robotic exploration missions (Blake et al. 2012; Igisu et al. 2009; Leroi et al. 2009). Samples analyzed include ultramafic rock and constituent mineral standards (e.g., olivine) and rocks collected from near surface sites associated with the NASA Astrobiology Institute-funded initiative, the Coast Range Ophiolite Microbial Observatory (CROMO), in Lower Lake, CA (Cardace et al. 2013). These new results provide co-registered, complementary data on astrobiologically important rock and mineral phases related to serpentinization (Crespo-Medina et al. 2014; Twing et al. 2017). Future work will leverage this data set in microbial colonization experiments aimed at parsing background organic loads in serpentinites from surficial/fracture-localized modern biofilm signatures.

  12. Columbite-Group Minerals from New York Pegmatites: Insights from Isotopic and Geochemical Analyses

    Directory of Open Access Journals (Sweden)

    Marian V. Lupulescu

    2018-05-01

    Full Text Available Columbite crystals from niobium-yttrium-fluorine (NYF pegmatites lacking zircon or containing metamict cyrtolite were analyzed for major and minor elements (Electron Microprobe (EMP, trace elements (Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS, and U-Pb geochronology (Laser AblationMulti-Collector-Inductively Coupled Plasma-Mass Spectrometry (LA-MC-ICP-MS. All four pegmatite localities sampled are hosted by the Proterozoic Fordham gneiss and/or Paleozoic Bedford gneiss (Columbite-(Fe; Kinkel and Baylis localities and the Manhattan Schist of Lower Paleozoic age (Columbite-(Mn; Fort George and Harlem River Drive localities and yield Neoacadian ages. The weighted average U-Pb ages are 372.2 ± 8.2 Ma (Baylis Quarry, 371.3 ± 7.3 and 383.4 ± 8.9 Ma (Kinkel Quarry; 383 ± 15 Ma (185th St. and Harlem River Drive; and 372 ± 10 Ma (Fort George. A partial metamict zircon (“cyrtolite” from the Kinkel Quarry yielded a weighted average U-Pb age of 376.9 ± 4.3 Ma. The Neoacadian ages obtained agree with those determined by thermal ionization mass spectrometry (TIMS for zircon from Lithium-Cesium-Tantalum (LCT pegmatites from Connecticut and Maine. No pegmatites temporally associated with the Taconic orogeny were found. The size, lack of common Pb, uniform U concentrations across crystal cross-sections, sufficient but moderate uranium concentrations, lack of metamictization, and consistency in U-Pb isotopic ratios for columbite samples BCB-COL, NYSM #25232, and NYSM #525.8 suggests they show promise as potential standards for oxide mineral LA-MC-ICP-MS geochronological analyses, however, additional characterization using ID-TIMS would be necessary to develop as such.

  13. Serpentinization as a reactive transport process: The brucite silicification reaction

    Science.gov (United States)

    Tutolo, Benjamin M.; Luhmann, Andrew J.; Tosca, Nicholas J.; Seyfried, William E.

    2018-02-01

    Serpentinization plays a fundamental role in the biogeochemical and tectonic evolution of the Earth and perhaps many other rocky planetary bodies. Yet, geochemical models still fail to produce accurate predictions of the various modes of serpentinization, which limits our ability to predict a variety of related geological phenomena over many spatial and temporal scales. Here, we use kinetic and reactive transport experiments to parameterize the brucite silicification reaction and provide fundamental constraints on SiO2 transport during serpentinization. We show that, at temperatures characteristic of the sub-seafloor at the serpentinite-hosted Lost City Hydrothermal Field (150 °C), the assembly of Si tetrahedra onto MgOH2 (i.e., brucite) surfaces is a rate-limiting elementary reaction in the production of serpentine and/or talc from olivine. Moreover, this reaction is exponentially dependent on the activity of aqueous silica (a SiO2 (aq)), such that it can be calculated according to the rate law:

  14. Contrasting serpentinization processes in the eastern Central Alps

    Science.gov (United States)

    Burkhard, D.J.M.; O'Neil, J.R.

    1988-01-01

    Stable isotope compositions have been determined for serpentinites from between Davos (Arosa-Platta nappe, Switzerland) and the Valmalenco (Italy). ??D and ??18O values (-120 to -60 and 6-10???, respectively) in the Arosa-Platta nappe indicate that serpentinization took place on the continent at relatively low temperatures in the presence of limited amounts of metamorphic fluids that contained a component of meteoric water. One sample of chrysotile has a ??18O value of 13??? providing evidence of high W/R ratios and low formation temperature of lizardite-chrysotile in this area. In contrast, relatively high ??D values (-42 to -34???) and low ??18O values (4.4-7.4???) for serpentine in the eastern part of the Valmalenco suggest a serpentinization process that took place at moderate temperatures in fluids that were dominated by ocean water. The antigorite in the Valmalenco is the first reported example of continental antigorite with an ocean water signature. An amphibole sample from a metasomatically overprinted contact zone to metasediments (??D=-36???) indicates that the metasomatic event also took place in the presence of ocean water. Lower ??D values (-93 to -60???) of serpentines in the western part of the Valmalenco suggest a different alteration history possibly influenced by fluids associated with contact metamorphism. Low water/rock ratios during regional metamorphism (and metasomatism) have to be assumed for both regions. ?? 1988 Springer-Verlag.

  15. The effect of polyether on the separation of pentlandite and serpentine

    Directory of Open Access Journals (Sweden)

    Xiaowen Zhou

    2015-10-01

    Full Text Available The effect of polyether on the separation of pentlandite from serpentine has been studied. In addition to flotation and sedimentation tests, electrophoresis and adsorption tests have been conducted. The flotation and sedimentation results show that serpentine impairs flotation performance of pentlandite, by adhering to the pentlandite particles. Addition of the polyether could promote the dispersion of the mixed sample of pentlandite and serpentine in alkaline conditions and significantly reduce adverse effects of serpentine on the pentlandite flotation. The electrophoresis and adsorption tests show that polyether can selectively adsorb onto pentlandite surface through hydrophobic reaction and remove serpentine slime particles from pentlandite surfaces by steric hindrance effect.

  16. Dynamics of soil chemistry in different serpentine habitats from Serbia

    Directory of Open Access Journals (Sweden)

    Vicić Dražen D.

    2014-01-01

    Full Text Available To enhance understanding of edaphic conditions in serpentine habitats, a thorough investigation of chemical and mechanical properties of three soils from disjunct ultramafic outcrops in the central Balkans was undertaken. Soil from a nearby chemically-contrasting limestone habitat was also analyzed. Three plant species differently associated with serpentine (Halacsya sendtneri, Cheilanthes marantae, and Seseli rigidum were references for site and soil selection. Twenty elements were scanned for, and fourteen were measured in seven sequentially-extracted soil fractions. Quantified soil properties also included: pH, levels of free CaCO3, organic matter, P2O5, K2O, N, C, S, cation exchange capacity, total organic carbon, field capacity and soil mechanical composition. The usual harsh components for plant growth in serpentine soil such as elevated Mg:Ca ratio, high levels of Ni, Cr, or Co, were significantly lower in the available fractions. There was a significant positive correlation of organic matter and field capacity, with most available Ca (70-80% found in the mobile, rather than the organically-bound fraction. This showed that a more favorable Mg:Ca ratio is highly dependent upon a higher field capacity, which is also in accordance with a more developed vegetation. Increasing the availability of metals (Al, Ba, Ca, Cr, Cu, Mg, Ni, Zn in a more developed serpentine grassland and forest vegetation, occurred only simultaneously with decrease of the Mg:Ca ratio and rise in other factors of fertility (N, P, K. Progressive development of ecosystem complexity therefore raised the availability of metals, but also reduced harsh Mg:Ca ratio disproportion, boosted levels of nutrients and raised soil field capacity. Principal components analysis confirmed that the main differences among serpentine habitats lay primarily in factors of fertility. The common habitat which hosts all three reference species offers intermediate conditions in a plant habitat

  17. Ex-situ and in-situ mineral carbonation as a means to sequester carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Gerdemann, Stephen J.; Dahlin, David C.; O' Connor, William K.; Penner, Larry R.; Rush, G.E.

    2004-01-01

    The U. S. Department of Energy's Albany Research Center is investigating mineral carbonation as a method of sequestering CO2 from coal-fired-power plants. Magnesium-silicate minerals such as serpentine [Mg3Si2O5(OH)4] and olivine (Mg2SiO4) react with CO2 to produce magnesite (MgCO3), and the calcium-silicate mineral, wollastonite (CaSiO3), reacts to form calcite (CaCO3). It is possible to carry out these reactions either ex situ (above ground in a traditional chemical processing plant) or in situ (storage underground and subsequent reaction with the host rock to trap CO2 as carbonate minerals). For ex situ mineral carbonation to be economically attractive, the reaction must proceed quickly to near completion. The reaction rate is accelerated by raising the activity of CO2 in solution, heat (but not too much), reducing the particle size, high-intensity grinding to disrupt the crystal structure, and, in the case of serpentine, heat-treatment to remove the chemically bound water. All of these carry energy/economic penalties. An economic study illustrates the impact of mineral availability and process parameters on the cost of ex situ carbon sequestration. In situ carbonation offers economic advantages over ex situ processes, because no chemical plant is required. Knowledge gained from the ex situ work was applied to long-term experiments designed to simulate in situ CO2 storage conditions. The Columbia River Basalt Group (CRBG), a multi-layered basaltic lava formation, has potentially favorable mineralogy (up to 25% combined concentration of Ca, Fe2+, and Mg cations) for storage of CO2. However, more information about the interaction of CO2 with aquifers and the host rock is needed. Core samples from the CRBG, as well as samples of olivine, serpentine, and sandstone, were reacted in an autoclave for up to 2000 hours at elevated temperatures and pressures. Changes in core porosity, secondary mineralizations, and both solution and solid chemistry were measured.

  18. Abiotic methane formation during experimental serpentinization of olivine.

    Science.gov (United States)

    McCollom, Thomas M

    2016-12-06

    Fluids circulating through actively serpentinizing systems are often highly enriched in methane (CH 4 ). In many cases, the CH 4 in these fluids is thought to derive from abiotic reduction of inorganic carbon, but the conditions under which this process can occur in natural systems remain unclear. In recent years, several studies have reported abiotic formation of CH 4 during experimental serpentinization of olivine at temperatures at or below 200 °C. However, these results seem to contradict studies conducted at higher temperatures (300 °C to 400 °C), where substantial kinetic barriers to CH 4 synthesis have been observed. Here, the potential for abiotic formation of CH 4 from dissolved inorganic carbon during olivine serpentinization is reevaluated in a series of laboratory experiments conducted at 200 °C to 320 °C. A 13 C-labeled inorganic carbon source was used to unambiguously determine the origin of CH 4 generated in the experiments. Consistent with previous high-temperature studies, the results indicate that abiotic formation of CH 4 from reduction of dissolved inorganic carbon during the experiments is extremely limited, with nearly all of the observed CH 4 derived from background sources. The results indicate that the potential for abiotic synthesis of CH 4 in low-temperature serpentinizing environments may be much more limited than some recent studies have suggested. However, more extensive production of CH 4 was observed in one experiment performed under conditions that allowed an H 2 -rich vapor phase to form, suggesting that shallow serpentinization environments where a separate gas phase is present may be more favorable for abiotic synthesis of CH 4 .

  19. A call to expand regulation to all carcinogenic fibrous minerals

    Science.gov (United States)

    Baumann, F.; Steele, I.; Ambrosi, J.; Carbone, M.

    2013-05-01

    The regulatory term "asbestos" groups only the six fibrous minerals that were commercially used among approximately 400. The carcinogenicity of these six regulated minerals has been largely demonstrated and is related to fiber structure, fiber length/diameter ratio, and bio-persistence. From a public perception, the generic term "asbestos" refers to the fibrous minerals that cause asbestosis, mesothelioma and other cancers. However, other non-regulated fibrous minerals are potentially as dangerous as the regulatory asbestos because they share similar physical and chemical properties, epidemiological studies have demonstrated their relationship with asbestos-related diseases, and both in vitro and in vivo experiments have established the toxicity of these minerals. For example, the non-regulated asbestiform winchite and richterite minerals that contaminated the vermiculite mined from Libby, Montana, (USA) were associated with mesothelioma, lung cancer and asbestosis observed among the area's residents and miners. Many other examples of non-regulated carcinogenic fibrous minerals include, but are not limited to, antigorite, arfvedsonite, balangeroite, carlosturanite, erionite, fluoro-edenite, hornblende, mordenite, palygorskite, and sepiolite. To propose a regulatory definition that would provide protection from all carcinogenic fibers, we have conducted an interdisciplinary literature review to compare the characteristics of "asbestos" and of non-regulated mineral fibers that relate to carcinogenicity. We specifically studied two non-regulated fibrous minerals that are associated with asbestos-related diseases: the serpentine antigorite and the zeolite erionite. Both examples underscore the problem of regulation based on commercial, rather than scientific principles: 1) the occurrence of fibrous antigorite in materials used to pave roads has been correlated with high mesothelioma rates in New Caledonia. Antigorite was also the cause of asbestosis in Poland, and in

  20. Difference in bone mineral density score on dual Xray absorptiometry scan among ethnic groups of Karachi, Pakistan

    International Nuclear Information System (INIS)

    Shaikh, S.A.; Iqbal, J.; Faisal, L.; Islam, Z.U.; Ajmal, R.

    2017-01-01

    To determine the bone mineral density (BMD) scores on Dual energy X ray absorptiometry (DEXA) scan in individuals of different ethnic groups among local population of Karachi, Pakistan. Methodology: This cross sectional study was conducted in Departments of Anatomy and Radiology, Liaquat National Hospital and Medical College Karachi, from June 2016 to March 2017. The data were collected from the patients belonging to different ethnic groups, who were referred for DEXA scan and entered on structured proforma. SPSS 21 was used for data analysis. Results: Out of 232 patients, 206 were females and 26 were males with mean age of 59.6+-10.06 years. Majority of patients were resident of Karachi and belonging to Urdu speaking ethnic group. Mean BMI of patients was 29.3 6.69 and most of patients with osteoporosis were preobese and obese with BMI >25. The relationship of BMD with different ethnic groups showed statistically significant difference where Baloch had high incidence of osteoporosis of forearm and lumbar spine while Sindhi and Pathan had osteoporosis of hip. Conclusion: There is significant difference in BMD score on DEXA scan among different ethnic groups of Karachi. This information can help clinicians advise patients for timely DEXA scan and earlier use of bone preservation treatment. (author)

  1. Mineral composition and geochemistry of the Upper Cretaceous siliciclastics (Nubia Group), Aswan District, south Egypt: Implications for provenance and weathering

    Science.gov (United States)

    Hassan, Abdallah M.

    2017-11-01

    The Upper-Cretaceous clastic succession (Nubia Group) in the area northeast of Aswan includes three rock units, from base upwards: Abu Aggag Formation (Turonian), Timsah Formation (Coniacian -Santonian) and Um Barmil Formation (Santonian - Campanian). Quartz and clay minerals are the predominant phases throughout the whole succession while feldspars are very rare. Kaolinite is overwhelming among the clay minerals, in addition to less important amounts of illite and illite/smectite. The ultrastable heavy minerals are the prevailing non- opaque phases and they significantly change in relative abundance upsection. SiO2, Al2O3 and Fe2O3 are the dominant chemical components. The statistical examination had revealed that the chemical constituents are loaded on three main geochemical trends; the siliceous, the argillaceous and the ferruginous. The enrichment factor shows that the geochemical behavior of the major and trace elements is uniform throughout the sandstones and mudstones of the Abu Aggag Formation. A significant geochemical contrast is documented between the sandstones and mudstones of both the Timsah and the Um Barmil formations. The provenance - critical elemental ratios Ti/Nb and Ti/Y are nearly constant throughout the sandstones and mudstones of the Abu Aggag Formation, and they fall within the range of granitic-granodioritic composition. The Timsah sandstones have Ti/Nb and Ti/Y ratios that are consistent with those of the Abu Aggag rocks, suggesting a similar provenance. These elemental ratios are extremely higher in the Timsah mudstones, reflecting a great influx of mafic material. The Um Barmil sandstones exhibit exceedingly dispersed values of Ti/Nb and Ti/Y, reflecting their derivation from large catchment's areas of different rock types with the eroded products being mixed in various relative proportions. The Ti/Nb and Ti/Y of the Um Barmil mudstones are closely akin to those of the Timsah mudstones suggesting analogous source. The chemical index of

  2. Serpentinization reaction pathways: implications for modeling approach

    Energy Technology Data Exchange (ETDEWEB)

    Janecky, D.R.

    1986-01-01

    Experimental seawater-peridotite reaction pathways to form serpentinites at 300/sup 0/C, 500 bars, can be accurately modeled using the EQ3/6 codes in conjunction with thermodynamic and kinetic data from the literature and unpublished compilations. These models provide both confirmation of experimental interpretations and more detailed insight into hydrothermal reaction processes within the oceanic crust. The accuracy of these models depends on careful evaluation of the aqueous speciation model, use of mineral compositions that closely reproduce compositions in the experiments, and definition of realistic reactive components in terms of composition, thermodynamic data, and reaction rates.

  3. Serpentinization: Getting water into a low permeability peridotite

    Science.gov (United States)

    Ulven, Ole Ivar

    2017-04-01

    Fluid consuming rock transformation processes occur in a variety of settings in the Earth's crust. One such process is serpentinization, which involves hydration of ultramafic rock to form serpentine. With peridotite being one of the dominating rocks in the oceanic crust, this process changes physical and chemical properties of the crust at a large scale, increases the amount of water that enters subduction zones, and might even affect plate tectonics te{jamtveit}. A significant number of papers have studied serpentinization in different settings, from reaction fronts progressing over hundreds of meters te{rudge} to the interface scale fracture initiation te{pluemper}. However, the process represents a complicated multi-physics problem which couples external stress, mechanical deformation, volume change, fracture formation, fluid transport, the chemical reaction, heat production and heat flow. Even though it has been argued that fracture formation caused by the volume expansion allows fluid infiltration into the peridotite te{rudge}, it remains unclear how sufficient water can enter the initially low permeability peridotite to pervasively serpentinize the rock at kilometre scale. In this work, we study serpentinization numerically utilizing a thermo-hydro-mechanical model extended with a fluid consuming chemical reaction that increases the rock volume, reduces its density and strength, changes the permeability of the rock, and potentially induces fracture formation. The two-way coupled hydromechanical model is based on a discrete element model (DEM) previously used to study a volume expanding process te{ulven_1,ulven_2} combined with a fluid transport model based on poroelasticity te{ulven_sun}, which is here extended to include fluid unsaturated conditions. Finally, a new model for reactive heat production and heat flow is introduced, to make this probably the first ever fully coupled chemo-thermo-hydromechanical model describing serpentinization. With this model

  4. Origin of multiple serpentinization events in New Caledonia

    Science.gov (United States)

    Ulrich, M.; Guillot, S.; Muñoz, M.; Picard, C.

    2011-12-01

    Studies on serpentinites around the world have shown that various polymorphs can coexist depending on the temperature, pressure and chemistry of the formation environment. Identifying serpentine polymorphs can thus provide significant constrains on the geodynamic environment at the time of formation. The New Caledonia ophiolite (Southwest Pacific) is one of the world's largest (500 km long, 50 km wide and 2 km thick). Emplaced during Eocene, it is thrust upon the continental Norfolk ridge, which derived from the splitting of the East Gondwana margin during Lower Late Cretaceous. The ophiolite consists of a large continuous massif occurring in the south of the island and some smaller isolated klippes located along the West coast. The peridotites are mostly harzburgite, related to a supra-subduction zone environment. The northernmost massifs are also composed of lherzolites, inherited from the opening of the South Loyalty Basin where the ophiolite was formed. Serpentinization is ubiquitous (usually >50%) independently from the nature of the peridotite. However, numerous studies have focused on the ophiolite but very few on the serpentinite. In this study, we use the Raman spectroscopy to identify serpentine polymorph in each part of the ophiolite. In situ trace element measurements were performed to constrain the behavior of fluid mobile element (FME: As, Sb, B, Li, Cs, Pb, U, Ba, Sr), and we are currently analyzing stable isotopic ratios to investigate the origin of fluids. Our results show that lizardite represents ~90% of the serpentine in the New Caledonia ophiolite. Only the serpentine sole has recorded multiple serpentinization events. In this horizon, the lizardite is crosscut by millimeter to centimeter antigorite veins. Chrysotile is the last polymorph to crystallize in millimeter crackseals. If the formation of the lizardite can be easily related to abyssal history of the ophiolite for the lherzolite and its supra-subduction history for the harzburgite, the

  5. Reactor design considerations in mineral sequestration of carbon dioxide

    International Nuclear Information System (INIS)

    Ityokumbul, M.T.; Chander, S.; O'Connor, William K.; Dahlin, David C.; Gerdemann, Stephen J.

    2001-01-01

    One of the promising approaches to lowering the anthropogenic carbon dioxide levels in the atmosphere is mineral sequestration. In this approach, the carbon dioxide reacts with alkaline earth containing silicate minerals forming magnesium and/or calcium carbonates. Mineral carbonation is a multiphase reaction process involving gas, liquid and solid phases. The effective design and scale-up of the slurry reactor for mineral carbonation will require careful delineation of the rate determining step and how it changes with the scale of the reactor. The shrinking core model was used to describe the mineral carbonation reaction. Analysis of laboratory data indicates that the transformations of olivine and serpentine are controlled by chemical reaction and diffusion through an ash layer respectively. Rate parameters for olivine and serpentine carbonation are estimated from the laboratory data

  6. Evidence of adaptive tolerance to nickel in isolates of Cenococcum geophilum from serpentine soils.

    Science.gov (United States)

    Gonçalves, Susana C; Martins-Loução, M Amélia; Freitas, Helena

    2009-04-01

    Selection for metal-tolerant ecotypes of ectomycorrhizal (ECM) fungi has been reported in instances of metal contamination of soils as a result of human activities. However, no study has yet provided evidence that natural metalliferous soils, such as serpentine soils, can drive the evolution of metal tolerance in ECM fungi. We examined in vitro Ni tolerance in isolates of Cenococcum geophilum from serpentine and non-serpentine soils to assess whether isolates from serpentine soils exhibited patterns consistent with adaptation to elevated levels of Ni, a typical feature of serpentine. A second objective was to investigate the relationship between Ni tolerance and specific growth rates (micro) among isolates to increase our understanding of possible tolerance/growth trade-offs. Isolates from both soil types were screened for Ni tolerance by measuring biomass production in liquid media with increasing Ni concentrations, so that the effective concentration of Ni inhibiting fungal growth by 50% (EC(50)) could be determined. Isolates of C. geophilum from serpentine soils exhibited significantly higher tolerance to Ni than non-serpentine isolates. The mean Ni EC(50) value for serpentine isolates (23.4 microg ml(-1)) was approximately seven times higher than the estimated value for non-serpentine isolates (3.38 microg ml(-1)). Although there was still a considerable variation in Ni sensitivity among the isolates, none of the serpentine isolates had EC(50) values for Ni within the range found for non-serpentine isolates. We found a negative correlation between EC(50) and micro values among isolates (r = -0.555). This trend, albeit only marginally significant (P = 0.06), indicates a potential trade-off between tolerance and growth, in agreement with selection against Ni tolerance in "normal" habitats. Overall, these results suggest that Ni tolerance arose among serpentine isolates of C. geophilum as an adaptive response to Ni exposure in serpentine soils.

  7. Age and geochemistry of the Charlestown Group, Ireland: Implications for the Grampian orogeny, its mineral potential and the Ordovician timescale

    Science.gov (United States)

    Herrington, Richard J.; Hollis, Steven P.; Cooper, Mark R.; Stobbs, Iain; Tapster, Simon; Rushton, Adrian; McConnell, Brian; Jeffries, Teresa

    2018-03-01

    Accurately reconstructing the growth of continental margins during episodes of ocean closure has important implications for understanding the formation, preservation and location of mineral deposits in ancient orogens. The Charlestown Group of county Mayo, Ireland, forms an important yet understudied link in the Caledonian-Appalachian orogenic belt located between the well documented sectors of western Ireland and Northern Ireland. We have reassessed its role in the Ordovician Grampian orogeny, based on new fieldwork, high-resolution airborne geophysics, graptolite biostratigraphy, U-Pb zircon dating, whole rock geochemistry, and an examination of historic drillcore from across the volcanic inlier. The Charlestown Group can be divided into three formations: Horan, Carracastle, and Tawnyinah. The Horan Formation comprises a mixed sequence of tholeiitic to calc-alkaline basalt, crystal tuff and sedimentary rocks (e.g. black shale, chert), forming within an evolving peri-Laurentian affinity island arc. The presence of graptolites Pseudisograptus of the manubriatus group and the discovery of Exigraptus uniformis and Skiagraptus gnomonicus favour a latest Dapingian (i.e. Yapeenian Ya 2/late Arenig) age for the Horan Formation (equivalent to c. 471.2-470.5 Ma according to the timescale of Sadler et al., 2009). Together with three new U-Pb zircon ages of 471.95-470.82 Ma from enclosing felsic tuffs and volcanic breccias, this fauna provides an important new constraint for calibrating the Middle Ordovician timescale. Overlying deposits of the Carracastle and Tawnyinah formations are dominated by LILE- and LREE-enriched calc-alkaline andesitic tuffs and flows, coarse volcanic breccias and quartz-feldspar porphyritic intrusive rocks, overlain by more silicic tuffs and volcanic breccias with rare occurrences of sedimentary rocks. The relatively young age for the Charlestown Group in the Grampian orogeny, coupled with high Th/Yb and zircon inheritance (c. 2.7 Ga) in intrusive

  8. Si-Metasomatism During Serpentinization of Jurassic Ultramafic Sea-floor: a Comparative Study

    Science.gov (United States)

    Vogel, M.; Frueh-Green, G. L.; Boschi, C.; Schwarzenbach, E. M.

    2014-12-01

    The Bracco-Levanto ophiolitic complex (northwestern Italy) represents one of the largest and better-exposed ophiolitic successions in the Northern Apennines. It is considered to be a fragment of heterogeneous Jurassic lithosphere that records tectono-magmatic and alteration histories similar to those documented along the Mid-Atlantic Ridge (MAR), such as at the 15°20'N area and the Atlantis Massif at 30°N. Structural and petrological studies on these rocks provide constraints on metamorphic/deformation processes during formation and hydrothermal alteration of the Jurassic oceanic lithosphere. We present a petrological and geochemical study of serpentinization processes and fluid-rock interaction in the Bracco-Levanto ophiolitic complex and compare these to published data from modern oceanic hydrothermal systems, such as the Lost City hydrothermal field hosted in serpentinites on the Atlantis Massif. Major element and mineral compositional data allow us to distinguish a multiphase history of alteration characterized by: (1) widespread Si-metasomatism during progressive serpentinization, and (2) multiple phases of veining and carbonate precipitation associated with circulation of seawater in the shallow ultramafic-dominated portions of the Jurassic seafloor, resulting in the formation of ophicalcites. In detail, regional variations in Si, Mg and Al content are observed in zones of ophicalcite formation, indicating metasomatic reactions and Si-Al transport during long-lived fluid-rock interaction and channelling of hydrothermal fluids. Rare earth element and isotopic analysis indicate that the Si-rich fluids are derived from alteration of pyroxenes to talc and tremolite in ultramafic rocks at depth. Comparison with serpentinites from the Atlantis Massif and 15°20'N indicates a similar degree of Si-enrichment in the modern seafloor and suggests that Si-metasomatism may be a fundamental process associated with serpentinization at slow-spreading ridge environments

  9. Ziminaite, Fe3+VO4, a new howardevansite-group mineral from the Bezymyannyi volcano, Kamchatka, Russia

    Science.gov (United States)

    Pekov, Igor V.; Siidra, Oleg I.; Yapaskurt, Vasiliy O.; Polekhovsky, Yury S.; Kartashov, Pavel M.

    2018-06-01

    The new mineral ziminaite, ideally Fe3+VO4, was found in fumarole sublimates at the Bezymyannyi volcano, Kamchatka, Russia. Ziminaite occurs as lamellar, tabular or flattened prismatic crystals up to 10 × 30 × 50 μm typically epitaxially overgrowing koksharovite, and as aggregates (up to 0.15 mm) associated with bannermanite in cavities in volcanic scoria. The mineral is translucent, yellowish-brown with an adamantine luster. The calculated density is 3.45 g cm- 3. In reflected light, ziminaite is light grey. Bireflectance is weak, internal reflections are deep yellow. The reflectance values [ R max -R min, % (λ, nm)] are: 17.7-16.3 (470), 15.7-14.1 (546), 15.1-13.8 (589), 14.7-13.6 (650). Chemical composition (wt%) is: MgO 2.20, CaO 0.01, Al2O3 7.81, Fe2O3 27.18, TiO2 4.50, SiO2 0.26, P2O5 0.09, V2O5 57.01, total 99.06. The empirical formula, based on 24 O atoms, is: (Fe3 + 3.29Al1.48Ti0.54Mg0.53)Σ5.84(V6.05Si0.04P0.01)Σ6.10O24 (Z = 1). Ziminaite is triclinic, P \\overline {1}, a 8.012(4), b 9.345(5), c 6.678(3) Å, α 106.992(10), β 101.547(8), γ 96.594(11)º, V 460.4(4) Å3, Z = 6. The strongest reflections of the powder X-ray diffraction pattern [ d,Å( I)( hkl)] are: 3.751(17)(1-21, 12 - 1), 3.539(86)(120), 3.270(67)(01-2), 3.209(100)(2-20), 3.090(20)(2-11, 002), 3.041(18)(03 - 1, 02-2), 2.934(14)(12 - 2, 030) and 1.665(24)(023, 12 - 4). The crystal structure, solved from single-crystal data ( R 1 = 0.085), is based upon heteropolyhedral framework built by VO4 tetrahedra and Fe3+-centred octahedra and five-fold polyhedra. Ziminaite belongs to the howardevansite group being its first member without species-defining uni- or divalent cations and with all large cation sites vacant. The mineral is named after the Zimina volcano situated near the discovery locality.

  10. Expedition 357 Preliminary Report: Atlantis Massif Serpentinization and Life

    OpenAIRE

    Früh-Green, GL; Orcutt, BN; Green, S; Cotterill, C; McCaig, AM; Expedition 357 Scientists,

    2016-01-01

    International Ocean Discovery Program (IODP) Expedition 357 successfully cored an east–west transect across the southern wall of Atlantis Massif on the western flank of the Mid-Atlantic Ridge to study the links between serpentinization processes and microbial activity in the shallow subsurface of highly altered ultramafic and mafic sequences that have been uplifted to the seafloor along a major detachment fault zone. The primary goals of this expedition were to (1) examine the role of serpent...

  11. Apparent Disequilibrium of Inorganic and Organic Carbon Compounds in Serpentinizing Fluids

    Science.gov (United States)

    Robinson, K.; Shock, E.

    2014-12-01

    During serpentinization of ultramafic rocks, ferrous iron in silicates is oxidized to ferric minerals and H2O is reduced to H2. This process is accompanied by the reduction of inorganic carbon, as observed in experiments and natural systems. To test the extent to which stable and metastable equilibria are reached among aqueous organic compounds during serpentinization, we sampled water and dissolved gases from circumneutral surface pools and hyperalkaline seeps in the Samail ophiolite in the Sultanate of Oman and analyzed for various carbon constituents, including dissolved inorganic carbon, dissolved organic carbon, methane, carbon monoxide, formate, acetate, and other small organic acid anions. Measurements of temperature, pH, dissolved H2, O2, major cations, major anions, and major and trace elements were also made. The aqueous composition of the analyzed samples was speciated based on ionic equilibrium interactions in order to obtain activities for inorganic carbon species, reduced carbon species, H2, and O2. The redox disequilibria among carbon species was then assessed using data and parameters for the revised HKF equations of state. This analysis demonstrates that the carbon species in this system are out of equilibrium with respect to one another in ways that cannot be compensated by altering the abundance of the other constituents within analytical uncertainties. Specifically, there is too much formate and too little methane relative to stable and metastable equilibria. This result implies the following: 1) Methane and formate equilibrated in separate parts of the system, given that no reasonable temperature, pressure, or composition changes satisfy equilibrium with their measured abundances. 2) Methane production is kinetically inhibited, as seen in experiments. 3) Microbial methane oxidation altered the abundance of methane and formate; methane oxidation to formate or carbonate is calculated to be extremely thermodynamically favorable in these fluids.

  12. Serpentine Coil Topology for BNL Direct Wind Superconducting Magnets

    CERN Document Server

    Parker, Brett

    2005-01-01

    BNL direct wind technology, with the conductor pattern laid out without need for extra tooling (no collars, coil presses etc.) began with RHIC corrector production. RHIC patterns were wound flat and then wrapped on cylindrical support tubes. Later for the HERA-II IR magnets we improved conductor placement precision by winding directly on a support tube. To meet HERA-II space and field quality goals took sophisticated coil patterns, (some wound on tapered tubes). We denote such patterns, topologically equivalent to RHIC flat windings, "planar patterns." Multi-layer planar patterns run into trouble because it is hard to wind across existing turns and magnet leads get trapped at poles. So we invented a new "Serpentine" winding style, which goes around 360 degrees while the conductor winds back and forth on the tube. To avoid making solenoidal fields, we wind Serpentine layers in opposite handed pairs. With a Serpentine pattern each turn can have the same projection on the coil axis and integral field harmonics t...

  13. Efficacy of woody biomass and biochar for alleviating heavy metal bioavailability in serpentine soil.

    Science.gov (United States)

    Bandara, Tharanga; Herath, Indika; Kumarathilaka, Prasanna; Hseu, Zeng-Yei; Ok, Yong Sik; Vithanage, Meththika

    2017-04-01

    Crops grown in metal-rich serpentine soils are vulnerable to phytotoxicity. In this study, Gliricidia sepium (Jacq.) biomass and woody biochar were examined as amendments on heavy metal immobilization in a serpentine soil. Woody biochar was produced by slow pyrolysis of Gliricidia sepium (Jacq.) biomass at 300 and 500 °C. A pot experiment was conducted for 6 weeks with tomato (Lycopersicon esculentum L.) at biochar application rates of 0, 22, 55 and 110 t ha -1 . The CaCl 2 and sequential extractions were adopted to assess metal bioavailability and fractionation. Six weeks after germination, plants cultivated on the control could not survive, while all the plants were grown normally on the soils amended with biochars. The most effective treatment for metal immobilization was BC500-110 as indicated by the immobilization efficiencies for Ni, Mn and Cr that were 68, 92 and 42 %, respectively, compared to the control. Biochar produced at 500 °C and at high application rates immobilized heavy metals significantly. Improvements in plant growth in biochar-amended soil were related to decreasing in metal toxicity as a consequence of metal immobilization through strong sorption due to high surface area and functional groups.

  14. Automated mapping of mineral groups and green vegetation from Landsat Thematic Mapper imagery with an example from the San Juan Mountains, Colorado

    Science.gov (United States)

    Rockwell, Barnaby W.

    2013-01-01

    Multispectral satellite data acquired by the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) and Landsat 7 Enhanced Thematic Mapper Plus (TM) sensors are being used to populate an online Geographic Information System (GIS) of the spatial occurrence of mineral groups and green vegetation across the western conterminous United States and Alaska. These geospatial data are supporting U.S. Geological Survey national-scale mineral deposit database development and other mineral resource and geoenvironmental research as a means of characterizing mineral exposures related to mined and unmined hydrothermally altered rocks and mine waste. This report introduces a new methodology for the automated analysis of Landsat TM data that has been applied to more than 180 scenes covering the western United States. A map of mineral groups and green vegetation produced using this new methodology that covers the western San Juan Mountains, Colorado, and the Four Corners Region is presented. The map is provided as a layered GeoPDF and in GIS-ready digital format. TM data analysis results from other well-studied and mineralogically characterized areas with strong hydrothermal alteration and (or) supergene weathering of near-surface sulfide minerals are also shown and compared with results derived from ASTER data analysis.

  15. Geochemistry of reduced gas related to serpentinization of the Zambales ophiolite, Philippines

    Science.gov (United States)

    Abrajano, T.A.; Sturchio, N.C.; Kennedy, B.M.; Lyon, G.L.; Muehlenbachs, K.; Böhlke, J.K.

    1990-01-01

    Methane-hydrogen gas seeps with mantle-like C and noble gas isotopic characteristics issue from partially serpentinized ultramafic rocks in the Zambales ophiolite, Philippines. New measurements of noble gas and 14C isotope abundances, rock/mixed-volatile equilibrium calculations, and previous chemical and isotopic data suggest that these reduced gases are products of periodotite hydration. The gas seeps are produced in rock-dominated zones of serpentinization, and similar gases may be ubiquitous in ultramafic terranes undergoing serpentinization.

  16. Controls of faulting and reaction kinetics on serpentinization and double Benioff zones

    OpenAIRE

    Iyer, Karthik; Rüpke, Lars H.; Phipps Morgan, Jason; Grevemeyer, Ingo

    2012-01-01

    The subduction of partially serpentinized oceanic mantle may potentially be the key geologic process leading to the regassing of Earth's mantle and also has important consequences for subduction zone processes such as element cycling, slab deformation, and intermediate-depth seismicity. However, little is known about the quantity of water that is retained in the slab during mantle serpentinization and the pattern of serpentinization that may occur during bending-related faulting; an initial s...

  17. Dynamic control on serpentine crystallization in veins: Constraints on hydration processes in oceanic peridotites

    OpenAIRE

    Andréani , Muriel; Mével , C.; Boullier , A.-M.; Escartín , J.

    2007-01-01

    International audience; Deformation and hydration processes are intimately linked in the oceanic lithosphere, but the feedbacks between them are still poorly understood, especially in ultramafic rocks where serpentinization results in a decrease of rock density that implies a volume increase and/or mass transfer. Serpentinization is accompanied by abundant veining marked by different generations of vein-filling serpentines with a high variety of morphologies and textures that correspond to di...

  18. Evaluation of serpentine ore as a nuclear shielding material using gas chromatographic techniques

    International Nuclear Information System (INIS)

    Singh, B.N.; Unnikrishnan, E.K.; Kumar, Sangita D.

    2007-01-01

    Serpentine ore mixed with cement has been recognized as a candidate shielding material for use in nuclear reactors because of its many desirable properties. Therefore the assessment of serpentine ore for release of volatile gases during exposure to elevated temperatures, irradiation and changes in chemical composition, is essential. The present paper deals with the studies on the serpentine ores using gas chromatography and combustion gas chromatographic techniques. (author)

  19. In situ speciation of the functional groups at mineral/electrolyte interfaces by sum frequency vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Floersheimer, M.; Kruse, K.; Klenze, R.; Kim, J.I. [Institut fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe (Germany); Fanghaenel, Th. [Institut fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe (Germany); Physikalisch-Chemisches Institut, Ruprecht-Karls-Universitaet Heidelberg, Im Neuenheimer Feld 253, D-69120, Heidelberg (Germany)

    2005-07-01

    Full text of publication follows: In order to describe surface reactivity and adsorption/desorption processes on the molecular level, a large number of functional groups has been postulated. In most cases, however, a direct proof for the existence of these species in real aquatic environment is lacking because it is difficult to obtain chemical analytical information in situ under electrolyte with interface selectivity. Here we apply interface selective sum frequency (SF) vibrational spectroscopy to study the (001) and (110) surfaces of sapphire ({alpha}-Al{sub 2}O{sub 3}) under water between pH 4 and 12. This work is part of an ongoing fundamental study of the sorption mechanism of actinides on single crystals faces of sapphire by various experimental and theoretical techniques. Sapphire is used as a simple model for natural clay minerals and related iron phases. In the O-H stretch region of the infrared spectrum between 2800 and 4000 cm{sup -1}, we observe a surprisingly large number of 8 SF bands in total. Two of them are due to the polar ordered water film near the mineral surface which is well known from various aquatic interfaces. The other bands originate from up to 6 different aluminol species or from specifically [1] bound water molecules. The prominent peak of the (001) surface (SF intensity maximum at 3690 cm{sup -1}), we attribute to an OH species bridging two [1-4] aluminium atoms. At the (110) surface, the concentration of this species is considerably smaller. Another aluminol species that can be detected at the (001) and the (110) surface (signal maximum near 3450 cm{sup -1}) exhibits O-H bonds which are almost parallel to the interface plane. This species is probably the in-plane aluminol group predicted in recent molecular dynamics calculations [4]. SF spectroscopy allows us also to measure the absolute polar orientation of the water molecules adjacent to the mineral surface. The inversion of the molecules polar orientation upon alteration of the p

  20. X-ray Photoelectron Spectroscopic and Raman microscopic investigation of the variscite group minerals: Variscite, strengite, scorodite and mansfieldite

    Science.gov (United States)

    Kloprogge, J. Theo; Wood, Barry J.

    2017-10-01

    Several structurally related AsO4 and PO4 minerals, were studied with Raman microscopy and X-ray Photoelectron Spectroscopy (XPS). XPS revealed only Fe, As and O for scorodite. The Fe 2p, As 3d, and O 1s indicated one position for Fe2 +, while 2 different environments for O and As were observed. The O 1s at 530.3 eV and the As 3d 5/2 at 43.7 eV belonged to AsO4, while minor bands for O 1s at 531.3 eV and As 3d 5/2 at 44.8 eV were due to AsO4 groups exposed on the surface possibly forming OH-groups. Mansfieldite showed, besides Al, As and O, a trace of Co. The PO4 equivalent of mansfieldite is variscite. The change in crystal structure replacing As with P resulted in an increase in the binding energy (BE) of the Al 2p by 2.9 eV. The substitution of Fe3 + for Al3 + in the structure of strengite resulted in a Fe 2p at 710.8 eV. An increase in the Fe 2p BE of 4.8 eV was found between mansfieldite and strengite. The scorodite Raman OH-stretching region showed a sharp band at 3513 cm- 1 and a broad band around 3082 cm- 1. The spectrum of mansfieldite was like that of scorodite with a sharp band at 3536 cm- 1 and broader maxima at 3100 cm- 1 and 2888 cm- 1. Substituting Al in the arsenate structure instead of Fe resulted in a shift of the metal-OH-stretching mode by 23 cm- 1 towards higher wavenumbers due to a slightly longer H-bonding in mansfieldite compared to scorodite. The intense band for scorodite at 805 cm- 1 was ascribed to the symmetric stretching mode of the AsO4. The medium intensity bands at 890, 869, and 830 cm- 1 were ascribed to the internal modes. A significant shift towards higher wavenumbers was observed for mansfieldite. The strengite Raman spectrum in the 900-1150 cm- 1 shows a strong band at 981 cm- 1 accompanied by a series of less intense bands. The 981 cm- 1 band was assigned to the PO4 symmetric stretching mode, while the weak band at 1116 cm- 1 was the corresponding antisymmetric stretching mode. The remaining bands at 1009, 1023 and 1035 cm- 1

  1. DEVELOPMENT OF A CO2 SEQUESTRATION MODULE BY INTEGRATING MINERAL ACTIVATION AND AQUEOUS CARBONATION. ANNUAL TECHNICAL PROGRESS REPORT

    International Nuclear Information System (INIS)

    George Alexander; M. Mercedes Maroto-Valer; Parvana Aksoy; Harold Schobert

    2006-01-01

    Mineral carbonation provides a potential option for the long-term storage of carbon dioxide. Serpentine has been chosen as the feedstock mineral, due to its abundance and availability. However, the relatively low reactivity of serpentine has warranted research into physical and chemical treatments that have been shown to greatly increase its reactivity. The use of sulfuric acid as an accelerating medium for the removal of magnesium from serpentine has recently been investigated. In addition to the challenges presented by the dissolution of serpentine, another challenge is the subsequent carbonation of the magnesium ions. A stable hydration sphere for the magnesium ion reduces the carbonation kinetics by obstructing the formation of the carbonation products. Accordingly, this research has evaluated the solubility of carbon dioxide in aqueous solution, the interaction between the dissociation products of carbon dioxide, and the carbonation potential of the magnesium ion

  2. Towards sustainable processing of columbite group minerals: elucidating the relation between dielectric properties and physico-chemical transformations in the mineral phase.

    Science.gov (United States)

    Sanchez-Segado, Sergio; Monti, Tamara; Katrib, Juliano; Kingman, Samuel; Dodds, Chris; Jha, Animesh

    2017-12-21

    Current methodologies for the extraction of tantalum and niobium pose a serious threat to human beings and the environment due to the use of hydrofluoric acid (HF). Niobium and tantalum metal powders and pentoxides are widely used for energy efficient devices and components. However, the current processing methods for niobium and tantalum metals and oxides are energy inefficient. This dichotomy between materials use for energy applications and their inefficient processing is the main motivation for exploring a new methodology for the extraction of these two oxides, investigating the microwave absorption properties of the reaction products formed during the alkali roasting of niobium-tantalum bearing minerals with sodium bicarbonate. The experimental findings from dielectric measurement at elevated temperatures demonstrate an exponential increase in the values of the dielectric properties as a result of the formation of NaNbO 3 -NaTaO 3 solid solutions at temperatures above 700 °C. The investigation of the evolution of the dielectric properties during the roasting reaction is a key feature in underpinning the mechanism for designing a new microwave assisted high-temperature process for the selective separation of niobium and tantalum oxides from the remainder mineral crystalline lattice.

  3. Relationships between global physical activity and bone mineral density in a group of male and female students.

    Science.gov (United States)

    Pasqualini, Leonella; Leli, Christian; Ministrini, Stefano; Schillaci, Giuseppe; Zappavigna, Rosa M; Lombardini, Rita; Scarponi, Anna M; Mannarino, Elmo

    2017-03-01

    Peak of bone mass (PBM) is generally reached about the age of 18 both in boys and girls. Maximizing PBM during growth may contribute to fracture risk reduction in adulthood and in the elderly. The aim of our study was to evaluate the effects on bone mineral density (BMD) of global physical activity (PA), carried out in the past 15 years, in a population of 70 healthy, young male and female subjects aged 22 to 25. BMD of the lumbar spine and total hip was measured using dual-energy X-ray absorptiometry (DEXA); global PA, resulting from sports-related, occupational and commuting PA, was evaluated using validated questionnaires. Women spent more time than men both in sports-related, occupational and commuting PA in the age range between 10-15 years. In the female group global PA positively correlated with BMD of the lumbar spine (r=0.38; P=0.02) and the total hip (r=0.36; P=0.04) and BMD of the lumbar spine was independently predicted by global PA and Body Mass Index. Our retrospective cross-sectional study indicates that global PA, not only sports-related PA, performed during prepubertal age, is associated with a greater PBM in women.

  4. Petrology and Rock Magnetism of the peridotites of Pindos Ophiolite (Greece), insights into the serpentinization process

    Science.gov (United States)

    Bonnemains, D.; Carlut, J. H.; Mevel, C.; Andreani, M.; Escartin, J.; Debret, B.

    2015-12-01

    We present a petrological and magnetic study of a suite of serpentinized peridotites from the Pindos ophiolite spanning a wide range in the degree of serpentinization (from ~10 to 100%). The Pindos ophiolite, in Northern Greece, is a portion of Late Triassic oceanic lithosphere obducted during the convergence of the Apulian and Pelagonian micro-continents. This ophiolite is interpreted mainly as the result of a supra-subduction zone spreading process but its complete history remains largely unknown. Therefore, it is not clear when the ultramafic section was exposed to fluid circulation that resulted in its serpentinization. Element partitioning during serpentinization reactions is dependent on parameters such as temperature and water-rock ratio. In particular, they affect the behavior of the iron released by olivine, which can be taken up either by magnetite, serpentine and/or brucite. Analyses of the reaction products are therefore a key to constrain the conditions during the main stage of the alteration. Our study was designed to gain insight on the conditions prevailing during hydration. Our results indicate that even fully serpentinized samples have a very low magnetization and magnetite content. Moreover, microprobe and μXanes results show that serpentine is the main host of iron in the divalent but also trivalent form. These results are compared with a set of data from serpentinized ultramafics sampled from the ocean floors, as well as from various other ophiolites. We suggest that serpentinization at Pindos occurred at relatively low-temperature (less than 200 °C), therefore not at a ridge environment. In addition, we stress that the presence of trivalent iron in serpentine indicates that serpentinization may remain a producer of hydrogen even when very little magnetite is formed.

  5. In situ electrochemical enrichment and isolation of a magnetite-reducing bacterium from a high pH serpentinizing spring.

    Science.gov (United States)

    Rowe, Annette R; Yoshimura, Miho; LaRowe, Doug E; Bird, Lina J; Amend, Jan P; Hashimoto, Kazuhito; Nealson, Kenneth H; Okamoto, Akihiro

    2017-06-01

    Serpentinization is a geologic process that produces highly reduced, hydrogen-rich fluids that support microbial communities under high pH conditions. We investigated the activity of microbes capable of extracellular electron transfer in a terrestrial serpentinizing system known as 'The Cedars'. Measuring current generation with an on-site two-electrode system, we observed daily oscillations in current with the current maxima and minima occurring during daylight hours. Distinct members of the microbial community were enriched. Current generation in lab-scale electrochemical reactors did not oscillate, but was correlated with carbohydrate amendment in Cedars-specific minimal media. Gammaproteobacteria and Firmicutes were consistently enriched from lab electrochemical systems on δ-MnO 2 and amorphous Fe(OH) 3 at pH 11. However, isolation of an electrogenic strain proved difficult as transfer cultures failed to grow after multiple rounds of media transfer. Lowering the bulk pH in the media allowed us to isolate a Firmicutes strain (Paenibacillus sp.). This strain was capable of electrode and mineral reduction (including magnetite) at pH 9. This report provides evidence of the in situ activity of microbes using extracellular substrates as sinks for electrons at The Cedars, but also highlights the potential importance of community dynamics for supporting microbial life through either carbon fixation, and/or moderating pH stress. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Evolution of spreading rate and H2 production by serpentinization at mid-ocean ridges from 200 Ma to Present

    Science.gov (United States)

    Andreani, M.; García del Real, P.; Daniel, I.; Wright, N.; Coltice, N.

    2017-12-01

    Mid-oceanic ridge (MOR) spreading rate spatially varies today from 20 to 200 mm/yr and geological records attest of important temporal variations, at least during the past 200 My. The spreading rate has a direct impact on the mechanisms accomodating extension (magmatic vs tectonic), hence on the nature of the rocks forming the oceanic lithosphere. The latter is composed of variable amount of magmatic and mantle rocks, that dominate at fast and (ultra-) slow spreading ridges, respectively. Serpentinization of mantle rocks contributes to global fluxes and notably to those of hydrogen and carbon by providing a pathways for dihydrogen (H2) production, carbone storage by mineralization, and carbon reduction to CH4 and possibly complex organic compounds. Quantification of the global chemical impact of serpentinization through geological time requires a coupling of geochemical parameters with plate-tectonic reconstructions. Here we quantify serpentinization extent and concurrent H2 production at MOR from the Jurassic (200 Ma) to present day (0 Ma). We coupled mean values of relevant petro-chemical parameters such as the proportion of mantle rocks, initial iron in olivine, iron redox state in serpentinites, % of serpentinization to high-resolution models of plate motion within the GPlates infrastructure to estimate the lengths in 1 Myr intervals for the global MOR plate boundary (spreading and transform components), and spreading ridges as a function of their rate. The model sensitivity to selected parameters has been tested. The results show that fragmentation of Pangea resulted in elevated H2 rates (>1012 to 1013 mol/yr) starting at 160 Ma compared to Late Mesozoic (<160 Ma) rates (<1011-1012 mol/yr). From 160 Ma to present, the coupled opening of the Atlantic and Indian oceans as well as the variation in spreading rates maintained H2 generation in the 1012 mol/yr level, but with significant excursions mainly related to the length of ultra-slow spreading segments. For

  7. Binding energy and mechanical stability of single- and multi-walled carbon nanotube serpentines

    International Nuclear Information System (INIS)

    Zhao, Junhua; Lu, Lixin; Rabczuk, Timon

    2014-01-01

    Recently, Geblinger et al. [Nat. Nanotechnol. 3, 195 (2008)] and Machado et al. [Phys. Rev. Lett. 110, 105502 (2013)] reported the experimental and molecular dynamics realization of S-like shaped single-walled carbon nanotubes (CNTs), the so-called CNT serpentines. We reported here results from continuum modeling of the binding energy γ between different single- and multi-walled CNT serpentines and substrates as well as the mechanical stability of the CNT serpentine formation. The critical length for the mechanical stability and adhesion of different CNT serpentines are determined in dependence of E i I i , d, and γ, where E i I i and d are the CNT bending stiffness and distance of the CNT translation period. Our continuum model is validated by comparing its solution to full-atom molecular dynamics calculations. The derived analytical solutions are of great importance for understanding the interaction mechanism between different single- and multi-walled CNT serpentines and substrates

  8. Geochemical bioenergetics during low-temperature serpentinization: An example from the Samail ophiolite, Sultanate of Oman

    Science.gov (United States)

    Canovas, Peter A.; Hoehler, Tori; Shock, Everett L.

    2017-07-01

    Various classes of microbial and biomolecular evidence from global studies in marine and continental settings are used to identify a set of reactions that appear to support microbial metabolism during serpentinization of ultramafic rocks. Geochemical data from serpentinizing ecosystems in the Samail ophiolite of Oman are used to evaluate the extent of disequilibria that can support this set of microbial metabolisms and to provide a ranking of potential metabolic energy sources in hyperalkaline fluids that are direct products of serpentinization. Results are used to construct hypotheses for how microbial metabolism may be supported in the subsurface for two cases: ecosystems hosted in rocks that have already undergone significant serpentinization and those hosted by deeper, active serpentinization processes.

  9. GIS-based identification of areas that have resource potential for critical minerals in six selected groups of deposit types in Alaska

    Science.gov (United States)

    Karl, Susan M.; Jones, James V.; Hayes, Timothy S.

    2016-11-16

    Alaska has considerable potential for undiscovered mineral resources. This report evaluates potential for undiscovered critical minerals in Alaska. Critical minerals are those for which the United States imports more than half of its total supply and which are largely derived from nations that cannot be considered reliable trading partners. In this report, estimated resource potential and certainty for the state of Alaska are analyzed and mapped for the following six selected mineral deposit groups that may contain one or more critical minerals: (1) rare earth elements-thorium-yttrium-niobium(-uranium-zirconium) [REE-Th-Y-Nb(-U-Zr)] deposits associated with peralkaline to carbonatitic igneous intrusive rocks; (2) placer and paleoplacer gold (Au) deposits that in some places might also produce platinum group elements (PGE), chromium (Cr), tin (Sn), tungsten (W), silver (Ag), or titanium (Ti); (3) platinum group elements(-cobalt-chromium-nickel-titanium-vanadium) [PGE(-Co-Cr-Ni-Ti-V)] deposits associated with mafic to ultramafic intrusive rocks; (4) carbonate-hosted copper(-cobalt-silver-germanium-gallium) [Cu(-Co-Ag-Ge-Ga)] deposits; (5) sandstone-hosted uranium(-vanadium-copper) [U(-V-Cu)] deposits; and (6) tin-tungsten-molybdenum(-tantalum-indium-fluorspar) [Sn-W-Mo(-Ta-In-fluorspar)] deposits associated with specialized granites.This study used a data-driven, geographic information system (GIS)-implemented method to identify areas that have mineral resource potential in Alaska. This method systematically and simultaneously analyzes geoscience data from multiple geospatially referenced datasets and uses individual subwatersheds (12-digit hydrologic units) as the spatial unit of classification. The final map output uses a red, yellow, green, and gray color scheme to portray estimated relative potential (High, Medium, Low, Unknown) for each of the six groups of mineral deposit types, and it indicates the relative certainty (High, Medium, Low) of that estimate for

  10. Out of the dark: transitional subsurface-to-surface microbial diversity in a terrestrial serpentinizing seep (Manleluag, Pangasinan, the Philippines).

    Science.gov (United States)

    Woycheese, Kristin M; Meyer-Dombard, D'Arcy R; Cardace, Dawn; Argayosa, Anacleto M; Arcilla, Carlo A

    2015-01-01

    In the Zambales ophiolite range, terrestrial serpentinizing fluid seeps host diverse microbial assemblages. The fluids fall within the profile of Ca(2+)-OH(-)-type waters, indicative of active serpentinization, and are low in dissolved inorganic carbon (DIC) (serpentinizing seep ecosystem studies, particularly with regards to tropical biomes.

  11. An inverted continental Moho and serpentinization of the forearc mantle.

    Science.gov (United States)

    Bostock, M G; Hyndman, R D; Rondenay, S; Peacock, S M

    2002-05-30

    Volatiles that are transported by subducting lithospheric plates to depths greater than 100 km are thought to induce partial melting in the overlying mantle wedge, resulting in arc magmatism and the addition of significant quantities of material to the overlying lithosphere. Asthenospheric flow and upwelling within the wedge produce increased lithospheric temperatures in this back-arc region, but the forearc mantle (in the corner of the wedge) is thought to be significantly cooler. Here we explore the structure of the mantle wedge in the southern Cascadia subduction zone using scattered teleseismic waves recorded on a dense portable array of broadband seismometers. We find very low shear-wave velocities in the cold forearc mantle indicated by the exceptional occurrence of an 'inverted' continental Moho, which reverts to normal polarity seaward of the Cascade arc. This observation provides compelling evidence for a highly hydrated and serpentinized forearc region, consistent with thermal and petrological models of the forearc mantle wedge. This serpentinized material is thought to have low strength and may therefore control the down-dip rupture limit of great thrust earthquakes, as well as the nature of large-scale flow in the mantle wedge.

  12. Fossil evidence for serpentinization fluids fueling chemosynthetic assemblages.

    Science.gov (United States)

    Lartaud, Franck; Little, Crispin T S; de Rafelis, Marc; Bayon, Germain; Dyment, Jerome; Ildefonse, Benoit; Gressier, Vincent; Fouquet, Yves; Gaill, Françoise; Le Bris, Nadine

    2011-05-10

    Among the deep-sea hydrothermal vent sites discovered in the past 30 years, Lost City on the Mid-Atlantic Ridge (MAR) is remarkable both for its alkaline fluids derived from mantle rock serpentinization and the spectacular seafloor carbonate chimneys precipitated from these fluids. Despite high concentrations of reduced chemicals in the fluids, this unique example of a serpentinite-hosted hydrothermal system currently lacks chemosynthetic assemblages dominated by large animals typical of high-temperature vent sites. Here we report abundant specimens of chemosymbiotic mussels, associated with gastropods and chemosymbiotic clams, in approximately 100 kyr old Lost City-like carbonates from the MAR close to the Rainbow site (36 °N). Our finding shows that serpentinization-related fluids, unaffected by high-temperature hydrothermal circulation, can occur on-axis and are able to sustain high-biomass communities. The widespread occurrence of seafloor ultramafic rocks linked to likely long-range dispersion of vent species therefore offers considerably more ecospace for chemosynthetic fauna in the oceans than previously supposed.

  13. CFD Models of a Serpentine Inlet, Fan, and Nozzle

    Science.gov (United States)

    Chima, R. V.; Arend, D. J.; Castner, R. S.; Slater, J. W.; Truax, P. P.

    2010-01-01

    Several computational fluid dynamics (CFD) codes were used to analyze the Versatile Integrated Inlet Propulsion Aerodynamics Rig (VIIPAR) located at NASA Glenn Research Center. The rig consists of a serpentine inlet, a rake assembly, inlet guide vanes, a 12-in. diameter tip-turbine driven fan stage, exit rakes or probes, and an exhaust nozzle with a translating centerbody. The analyses were done to develop computational capabilities for modeling inlet/fan interaction and to help interpret experimental data. Three-dimensional Reynolds averaged Navier-Stokes (RANS) calculations of the fan stage were used to predict the operating line of the stage, the effects of leakage from the turbine stream, and the effects of inlet guide vane (IGV) setting angle. Coupled axisymmetric calculations of a bellmouth, fan, and nozzle were used to develop techniques for coupling codes together and to investigate possible effects of the nozzle on the fan. RANS calculations of the serpentine inlet were coupled to Euler calculations of the fan to investigate the complete inlet/fan system. Computed wall static pressures along the inlet centerline agreed reasonably well with experimental data but computed total pressures at the aerodynamic interface plane (AIP) showed significant differences from the data. Inlet distortion was shown to reduce the fan corrected flow and pressure ratio, and was not completely eliminated by passage through the fan

  14. Inclusions of crichtonite-group minerals in Cr-pyropes from the Internatsionalnaya kimberlite pipe, Siberian Craton: Crystal chemistry, parageneses and relationships to mantle metasomatism

    Science.gov (United States)

    Rezvukhin, Dmitriy I.; Malkovets, Vladimir G.; Sharygin, Igor S.; Tretiakova, Irina G.; Griffin, William L.; O'Reilly, Suzanne Y.

    2018-05-01

    Cr-pyrope xenocrysts and associated inclusions of crichtonite-group minerals from the Internatsionalnaya kimberlite pipe were studied to provide new insights into processes in the lithospheric mantle beneath the Mirny kimberlite field, Siberian craton. Pyropes are predominantly of lherzolitic paragenesis (Cr2O3 2-6 wt%) and have trace-element spectra typical for garnets from fertile mantle (gradual increase in chondrite-normalized values from LREE to MREE-HREE). Crichtonite-group minerals commonly occur as monomineralic elongated inclusions, mostly in association with rutile, Mg-ilmenite and Cr-spinel within individual grains of pyrope. Sample INT-266 hosts intergrowth of crichtonite-group mineral and Cl-apatite, while sample INT-324 contains polymineralic apatite- and dolomite-bearing assemblages. Crichtonite-group minerals are Al-rich (1.1-4.5 wt% Al2O3), moderately Zr-enriched (1.3-4.3 wt% ZrO2), and are Ca-, Sr-, and occasionally Ba-dominant in terms of A-site occupancy; they also contain significant amounts of Na and LREE. T-estimates and chemical composition of Cr-pyropes imply that samples represent relatively low-T peridotite assemblages with ambient T ranging from 720 to 820°С. Projected onto the 35 mW/m2 cratonic paleogeotherm for the Mirny kimberlite field (Griffin et al., 1999b. Tectonophysics 310, 1-35), temperature estimates yield a P range of 34-42 kbar ( 110-130 km), which corresponds to a mantle domain in the uppermost part of the diamond stability field. The presence of crichtonite-group minerals in Cr-pyropes has petrological and geochemical implications as evidence for metasomatic enrichment of some incompatible elements in the lithospheric mantle beneath the Mirny kimberlite field. The genesis of Cr-pyropes with inclusions of crichtonite-group minerals is attributed to the percolation of Ca-Sr-Na-LREE-Zr-bearing carbonate-silicate metasomatic agents through Mg- and Cr-rich depleted peridotite protoliths. The findings of several potentially

  15. Astrophyllite-group minerals from the Ilímaussaq complex, South Greenland (contribution to the mineralogy of Ilímaussaq no. 123)

    DEFF Research Database (Denmark)

    Macdonald, R.; Karup-Møller, Sven; Rose-Hansen, J.

    2007-01-01

    in the formation of kupletskite in some rocks. Altered zones in certain astrophyllites and niobophyllites have compositional features similar to the type 'hydroastrophyllite'. The astrophyllite-group minerals in the hydrothermal veins crystallized at temperatures below 400°C at 1 kbar and under high pH and low......Electron microprobe analyses are presented for astrophyllite-group minerals from hydrothermal veins and pegmatites of the Ilimaussaq complex, South Greenland. The analyses fall mainly into two groups: (1) niobophyllites with the highest Nb/(Nb+Ti) ratios yet recorded (∼0.9), occurring only...... oxygen fugacity, whereas those in the pegmatites were formed from water-rich melts which were hotter (≥450°C), less basic and more oxidized. © 2007 The Mineralogical Society....

  16. Rhizosphere characteristics of indigenously growing nickel hyperaccumulator and excluder plants on serpentine soil

    International Nuclear Information System (INIS)

    Wenzel, W.W.; Bunkowski, M.; Puschenreiter, M.; Horak, O.

    2003-01-01

    Field study reinforces that root exudates may contribute to nickel hyperaccumulation in Thlaspi goesingense Halacsy. - The role of rhizosphere processes in metal hyperaccumulation is largely unexplored and a matter of debate, related field data are virtually not available. We conducted a field survey of rhizosphere characteristics beneath the Ni hyperaccumulator Thlaspi goesingense Halacsy and the metal-excluder species Silene vulgaris L. and Rumex acetosella L. growing natively on the same serpentine site. Relative to bulk soil and to the rhizosphere of the excluder species, we found significantly increased DOC and Ni concentrations in water extracts of T. goesingense rhizosphere, whereas exchangeable Ni was depleted due to excessive uptake of Ni. Chemical speciation analysis using the MINTEQA2 software package revealed that enhanced Ni solubility in Thlaspi rhizosphere is driven by the formation of Ni-organic complexes. Moreover, ligand-induced dissolution of Ni-bearing minerals is likely to contribute to enhanced Ni solubility. Increased Mg and Ca concentrations and pH in Thlaspi rhizosphere are consistent with ligand-induced dissolution of orthosilicates such as forsterite (Mg 2 SiO 4 ). Our field data reinforce the hypothesis that exudation of organic ligands may contribute to enhanced solubility and replenishment of metals in the rhizosphere of hyperaccumulating species

  17. Stable isotope study of serpentinization and metamorphism in the Highland Border Suite, Scotland, UK

    Energy Technology Data Exchange (ETDEWEB)

    Ikin, N.P. (University Coll., Cardiff (UK)); Harmon, R.S. (Southern Methodist Univ., Dallas, TX (USA))

    1983-02-01

    D/H and /sup 18/O//sup 16/O ratios have been measured for whole-rock samples and mineral separates from the mafic and ultramafic rocks of the Cambro-Ordovician Highland Border Suite. The H- and O-isotopic compositions of these rocks record individual stages in a relatively complex 500 Myr old hydrothermal/ metamorphic history. Lizardite serpentinites record a premetamorphic history and indicate that parent harzburgites, dunites, and pyroxenites were serpentinized through low-temperature interaction with meteoric waters during cooling. The other rocks of the Highland Border Suite record subsequent interaction with metamorphic fluids. Amphibolite facies hornblende schists were produced through thrust-related metamorphism of spilitic pillow lavas. During dehydration, D-enriched fluids were driven off from the spilites thus leaving the hornblende schists to equilibrate with a relatively D-depleted internal fluid reservoir. The expelled D-enriched fluids may have mixed with more typical Dalradian metamorphic waters which then exchanged with the remaining mafic rocks and lizardite serpentinites during greenschist facies regional metamorphism to produce antigorite serpentinites and greenschist metaspilites with similar H- and O-isotopic compositions. Serpentinites which have been only partially metamorphosed show intermediate H-isotopic compositions between that of metamorphic antigorite and non-metamorphic lizardite end members.

  18. A stable isotope study of serpentinization and metamorphism in the Highland Border Suite, Scotland, UK

    International Nuclear Information System (INIS)

    Ikin, N.P.; Harmon, R.S.

    1983-01-01

    D/H and 18 O/ 16 O ratios have been measured for whole-rock samples and mineral separates from the mafic and ultramafic rocks of the Cambro-Ordovician Highland Border Suite. The H- and O-isotopic compositions of these rocks record individual stages in a relatively complex 500 Myr old hydrothermal/ metamorphic history. Lizardite serpentinites record a premetamorphic history and indicate that parent harzburgites, dunites, and pyroxenites were serpentinized through low-temperature interaction with meteoric waters during cooling. The other rocks of the Highland Border Suite record subsequent interaction with metamorphic fluids. Amphibolite facies hornblende schists were produced through thrust-related metamorphism of spilitic pillow lavas. During dehydration, D-enriched fluids were driven off from the spilites thus leaving the hornblende schists to equilibrate with a relatively D-depleted internal fluid reservoir. The expelled D-enriched fluids may have mixed with more typical Dalradian metamorphic waters which then exchanged with the remaining mafic rocks and lizardite serpentinites during greenschist facies regional metamorphism to produce antigorite serpentinites and greenschist metaspilites with similar H- and O-isotopic compositions. Serpentinites which have been only partially metamorphosed show intermediate H-isotopic compositions between that of metamorphic antigorite and non-metamorphic lizardite end members. (author)

  19. Mineral Fractionation during Sediment Comminution and Transport in Fluvio-Deltaic and Lacustrine Rocks of the Bradbury Group, Gale Crater, Mars

    Science.gov (United States)

    Siebach, K. L.; Baker, M. B.; Grotzinger, J. P.; McLennan, S. M.; Gellert, R.; Thompson, L. M.; Hurowitz, J.

    2017-12-01

    Mineral distribution patterns in sediments of the Bradbury group in Gale crater, interpreted from observations by the Mars Science Laboratory rover Curiosity, show the importance of transport mechanics in source-to-sink processes on Mars. The Bradbury group is comprised of basalt-derived mudstones to conglomerates exposed along the modern floor of Gale crater and analyzed along a 9-km traverse of the Curiosity rover. Over 110 bulk chemistry analyses of the rocks were acquired, along with two XRD mineralogical analyses of the mudstone. These rocks are uniquely suited for analysis of source-to-sink processes because they exhibit a wide range of compositions, but (based on multiple chemical weathering proxies) they appear to have experienced negligible cation-loss during weathering and erosion. Chemical variations between analyses correlate with sediment grain sizes, with coarser-grained rocks enriched in plagioclase components SiO2, Al2O3, and Na2O, and finer-grained rocks enriched in components of mafic minerals, consistent with grain-size sorting of mineral fractions during sediment transport. Further geochemical and mineralogical modeling supports the importance of mineral fractionation: even though the limited XRD data suggests that some fraction (if not all) of the rocks contain clays and an amorphous component, models show that 90% of the compositions measured are consistent with sorting of primary igneous minerals from a plagioclase-phyric subalkaline basalt (i.e., no corrections for cation-loss are required). The distribution of K2O, modeled as a potassium feldspar component, is an exception to the major-element trends because it does not correlate with grain size, but has an elevation-dependent signal likely correlated with the introduction of a second source material. However, the dominant compositional trends within the Bradbury group sedimentary rocks are correlated with grain size and consistent with mineral fractionation of minimally

  20. Active Microbial Sulfate Reduction in Serpentinization Fluids of the Semail Ophiolite in Oman

    Science.gov (United States)

    Glombitza, C.; Rempfert, K. R.; Templeton, A. S.; Hoehler, T. M.

    2017-12-01

    Dissimilatory sulfate reduction (SR) is among the oldest known microbial processes on Earth. It is the predominant anaerobic microbial process in sulfur-rich marine sediments but it also occurs in subsurface lithoautotrophic ecosystems, where it is driven by radiolytically produced H2 and sulfate [1]. Serpentinization is a process by which H2 is generated in a reaction of water with peridotite rock. This abiotic generation of H2 suggests its potential to power life in rocks as a stand-alone process, independent of the photosynthetic biosphere, because the generated H2 is a key energy source for microbial metabolism. This is of particular interest in understanding the role of water-rock reactions in generating habitable conditions on and beyond Earth. Sulfate is plausibly available in several of the water-bearing environments now known beyond Earth, making SR a potentially important metabolism in those systems. Sulfate minerals are abundant on the surface of Mars [2], suggesting that Martian groundwaters may be sulfate-rich. Sulfate is also postulated to be a component of the oceans of Europa and Enceladus [3, 4]. The inferred presence of both sulfate and peridotite rocks in these environments points toward a potential niche for sulfate reducers and highlights the need to understand how and where SR occurs in serpentinizing systems on Earth. We incubated formation fluids sampled from in the Semail Ophiolite in Oman with a 35-S labelled sulfate tracer and determined the rates of in-situ microbial sulfate reduction. The selected fluids represent different environmental conditions, in particular varying substrate concentrations (sulfate, H2 and CH4) and pH (pH 8.4 to pH 11.2). We found active microbial SR at very low rates in almost all fluids, ranging from 2 fmol mL-1 d-1 to 2 pmol mL-1 d-2. Lowest rates were associated with the hyperalkaline fluids (pH > 10), that had also the lowest sulfate concentration (50-90 µmol L-1). In line with previously determined species

  1. Detection of serpentine in exogenic carbonaceous chondrite material on Vesta from Dawn FC data

    Science.gov (United States)

    Nathues, Andreas; Hoffmann, Martin; Cloutis, Edward A.; Schäfer, Michael; Reddy, Vishnu; Christensen, Ulrich; Sierks, Holger; Thangjam, Guneshwar Singh; Le Corre, Lucille; Mengel, Kurt; Vincent, Jean-Baptist; Russell, Christopher T.; Prettyman, Tom; Schmedemann, Nico; Kneissl, Thomas; Raymond, Carol; Gutierrez-Marques, Pablo; Hall, Ian; Büttner, Irene

    2014-09-01

    The Dawn mission’s Framing Camera (FC) observed Asteroid (4) Vesta in 2011 and 2012 using seven color filters and one clear filter from different orbits. In the present paper we analyze recalibrated HAMO color cubes (spatial resolution ∼60 m/pixel) with a focus on dark material (DM). We present a definition of highly concentrated DM based on spectral parameters, subsequently map the DM across the Vestan surface, geologically classify DM, study its spectral properties on global and local scales, and finally, compare the FC in-flight color data with laboratory spectra. We have discovered an absorption band centered at 0.72 μm in localities of DM that show the lowest albedo values by using FC data as well as spectral information from Dawn’s imaging spectrometer VIR. Such localities are contained within impact-exposed outcrops on inner crater walls and ejecta material. Comparisons between spectral FC in-flight data, and laboratory spectra of meteorites and mineral mixtures in the wavelength range 0.4-1.0 μm, revealed that the absorption band can be attributed to the mineral serpentine, which is typically present in CM chondrites. Dark material in its purest form is rare on Vesta’s surface and is distributed globally in a non-uniform manner. Our findings confirm the hypothesis of an exogenic origin of the DM by the infall of carbonaceous chondritic material, likely of CM type. It further confirms the hypothesis that most of the DM was deposited by the Veneneia impact.

  2. Mineral resources and energy. Report by the 'Soil and underground' group of the Ancre Alliance

    International Nuclear Information System (INIS)

    2015-06-01

    After comments on the growth of the world consumption of raw materials, on the relocation of productions and on the loss of interest by industrialized countries in mineral resources and their dependency, and a discussion of the relationship between energy and mineral raw materials, this study proposes an assessment and a discussion of energy needs for mining and metal industries. In the next part, needs in raw materials for the energy sector are analysed and discussed with respect to their field of application, to their intensity, to energy scenarios, and to application to research. The value chain is then analysed as well as its risks which can be political, industrial, related to infrastructures, economic, environmental, geological, technical, or social. Recycling capacities and the potential of substitution are then addressed. Themes and axis of research are identified for the assessment of needs, social acceptability, geology and exploration, mining, ore processing and metal industry, recycling, and substitution

  3. Interrelation between rifting, faulting, sedimentation, and mantle serpentinization during continental margin formation

    Science.gov (United States)

    Rupke, L.; Schmid, D. W.; Perez-Gussinye, M.; Hartz, E. H.

    2013-12-01

    We explore the conditions under which mantle serpentinization may take place during continental rifting with 2D thermotectonostratigraphic basin models. The basic concept follows the idea that the entire extending continental crust has to be brittle for crustal scale faulting and mantle serpentinization to occur. The new model tracks the rheological evolution of the continental crust and allows for kinetically controlled mantle serpentinization processes. The isostatic and latent heat effects of the reaction are fully coupled to the structural and thermal solutions. A systematic parameter study shows that a critical stretching factor exists for which complete crustal embrittlement and serpentinization occurs. Sedimentation shifts this critical stretching factor to higher values as both deeper burial and the low thermal conductivity of sediments lead to higher crustal temperatures. Serpentinization reactions are therefore only likely in settings with low sedimentation rates and high stretching factors. In addition, we find that the rate of sediment supply has first order controls on the rheology of the lower crust, which may control the overall margin geometry. We further test these concepts in ideas in a case study for the Norwegian margin. In particular, we evaluate whether the inner lower crustal bodies (LCB) imaged beneath the More and Voring margin could be serpentinized mantle. For this purpose we reconstruct multiple 2D transects through a 3D data set. This reconstruction of the Norwegian margin shows that serpentinization reactions are indeed possible and likely during the Jurassic rift phase. Predicted present-day thicknesses and locations of partially serpentinized mantle rocks fit well to information on LCBs from seismic and gravity data. We conclude that some of the inner LCBs beneath the Norwegian margin may, in fact, be partially serpentinized mantle.

  4. What is CCZN-armalcolite? A crystal-chemical discussion and an ad-hoc incursion in the crichtonite-minerals group

    Directory of Open Access Journals (Sweden)

    Gavril Sabau

    2007-10-01

    Full Text Available The status of CCZN-armalcolite, commonly still believed to be a variety of armalcolite s.s., is questionable in view of partial evidence suggesting that it would represent a distinct phase, as initially claimed by its discoverers. Because of the rarity of the mineral, combined with its habitual small grain-size, no successful structural investigation could be undertaken so far. Therefore we attempted a chemical overview of existing and original data pertaining to CCZN-armalcolite. With the view of systematizing structure-composition relationships, we analyzed the topology of large cations – bearing close-packed oxides, while extending the nomenclature in use in order to accommodate further topologies. By using relevant chemical plots, a fair compositional match between CCZN-armalcolite and the crichtonite group minerals was demonstrated, as well as a chemical incompatibility with armalcolite. Stoichiometric crichtonite compositions and matching optical properties allowed identification of at least part of “CCZN-armalcolites” with the mineral loveringite of the crichtonite group. A detailed inspection of structure-composition relationships in crichtonites allowed an insight in their trends and range of chemical variation, as well as a comparison between them and a group of “CCZN-armalcolites” slightly differing from known crichtonites. These “CCZN-armalcolites” departing from normal chemical trends in crichtonites either represent an ordered variety of non-stoichiometric crichtonite or a new group of close-packed oxides. Their composition clustering around formula AM16O30 is temptingly consistent with an hypothetical structure intermediate between magnetoplumbites and crichtonites, based on close-packed stacking of layers made up by triangular clusters of octahedra, stuffed with large cations. A model of such a structure, not encountered so far in minerals, is outlined, displaying a hexagonal symmetry P , with a ≈ 7.45Å and c

  5. Carbon dioxide sequestration by aqueous mineral carbonation of magnesium silicate minerals

    Energy Technology Data Exchange (ETDEWEB)

    Gerdemann, Stephen J.; Dahlin, David C.; O' Connor, William K.; Penner, Larry R.

    2003-01-01

    The dramatic increase in atmospheric carbon dioxide since the Industrial Revolution has caused concerns about global warming. Fossil-fuel-fired power plants contribute approximately one third of the total human-caused emissions of carbon dioxide. Increased efficiency of these power plants will have a large impact on carbon dioxide emissions, but additional measures will be needed to slow or stop the projected increase in the concentration of atmospheric carbon dioxide. By accelerating the naturally occurring carbonation of magnesium silicate minerals it is possible to sequester carbon dioxide in the geologically stable mineral magnesite (MgCO3). The carbonation of two classes of magnesium silicate minerals, olivine (Mg2SiO4) and serpentine (Mg3Si2O5(OH)4), was investigated in an aqueous process. The slow natural geologic process that converts both of these minerals to magnesite can be accelerated by increasing the surface area, increasing the activity of carbon dioxide in the solution, introducing imperfections into the crystal lattice by high-energy attrition grinding, and in the case of serpentine, by thermally activating the mineral by removing the chemically bound water. The effect of temperature is complex because it affects both the solubility of carbon dioxide and the rate of mineral dissolution in opposing fashions. Thus an optimum temperature for carbonation of olivine is approximately 185 degrees C and 155 degrees C for serpentine. This paper will elucidate the interaction of these variables and use kinetic studies to propose a process for the sequestration of the carbon dioxide.

  6. [Update of recommendations for evaluation and treatment of osteoporosis associated to endocrine and nutritional conditions. Working Group on Osteoporosis and Mineral Metabolism of the Spanish Society of Endocrinology].

    Science.gov (United States)

    Reyes-García, Rebeca; García-Martín, Antonia; Varsavsky, Mariela; Rozas-Moreno, Pedro; Cortés-Berdonces, María; Luque-Fernández, Inés; Gómez Sáez, José Manuel; Vidal Casariego, Alfonso; Romero Muñoz, Manuel; Guadalix Iglesias, Sonsoles; Fernández García, Diego; Jódar Gimeno, Esteban; Muñoz Torres, Manuel

    2015-05-01

    To update previous recommendations developed by the Working Group on Osteoporosis and Mineral Metabolism of the Spanish Society of Endocrinology and Nutrition for the evaluation and treatment of osteoporosis associated to different endocrine and nutritional diseases. Members of the Working Group on Osteoporosis and Mineral Metabolism of the Spanish Society of Endocrinology and Nutrition. Recommendations were formulated according to the GRADE system (Grading of Recommendations, Assessment, Development, and Evaluation) to describe both the strength of recommendations and the quality of evidence. A systematic search was made in MEDLINE (Pubmed) using the following terms associated to the name of each condition: AND "osteoporosis", "fractures", "bone mineral density", and "treatment". Papers in English with publication date between 18 October 2011 and 30 October 2014 were included. The recommendations were discussed and approved by all members of the Working Group. This update summarizes the new data regarding evaluation and treatment of osteoporosis associated to endocrine and nutritional conditions. Copyright © 2015 SEEN. Published by Elsevier España, S.L.U. All rights reserved.

  7. Origins of high pH mineral waters from ultramafic rocks, Central Portugal

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Jose M. [Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001, Lisboa (Portugal)], E-mail: jose.marques@ist.ult.pt; Carreira, Paula M. [Instituto Tecnologico e Nuclear, Estrada Nacional No 10, 2686-953 Sacavem (Portugal); Carvalho, Maria Rosario [Departamento de Geologia, Faculdade de Ciencias, Universidade de Lisboa, Ed. C6, 3oP, Campo Grande, 1749-016 Lisboa (Portugal); Matias, Maria J. [Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001, Lisboa (Portugal); Goff, Fraser E. [Earth and Planetary Sciences Department MSCO3-2040, University of New Mexico, Albuquerque, New Mexico 87131-000 (United States); Basto, Maria J.; Graca, Rui C.; Aires-Barros, Luis [Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001, Lisboa (Portugal); Rocha, Luis [Junta de Freguesia, Av. da Libertacao, 45-D, 7460-002, Cabeco de Vide (Portugal)

    2008-12-15

    This paper reviews the geochemical, isotopic ({sup 2}H, {sup 18}O, {sup 13}C, {sup 3}H and {sup 14}C) and numerical modelling approaches to evaluate possible geological sources of the high pH (11.5)/Na-Cl/Ca-OH mineral waters from the Cabeco de Vide region (Central-Portugal). Water-rock interaction studies have greatly contributed to a conceptual hydrogeological circulation model of the Cabeco de Vide mineral waters, which was corroborated by numerical modelling approaches. The local shallow groundwaters belong to the Mg-HCO{sub 3} type, and are derived by interaction with the local serpentinized rocks. At depth, these type waters evolve into the high pH/Na-Cl/Ca-OH mineral waters of Cabeco de Vide spas, issuing from the intrusive contact between mafic/ultramafic rocks and an older carbonate sequence. The Cabeco de Vide mineral waters are supersaturated with respect to serpentine indicating that they may cause serpentinization. Magnesium silicate phases (brucite and serpentine) seem to control Mg concentrations in Cabeco de Vide mineral waters. Similar {delta}{sup 2}H and {delta}{sup 18}O suggest a common meteoric origin and that the Mg-HCO{sub 3} type waters have evolved towards Cabeco de Vide mineral waters. The reaction path simulations show that the progressive evolution of the Ca-HCO{sub 3} to Mg-HCO{sub 3} waters can be attributed to the interaction of meteoric waters with serpentinites. The sequential dissolution at CO{sub 2} (g) closed system conditions leads to the precipitation of calcite, magnesite, amorphous silica, chrysotile and brucite, indicating that the waters would be responsible for the serpentinization of fresh ultramafic rocks (dunites) present at depth. The apparent age of Cabeco de Vide mineral waters was determined as 2790 {+-} 40 a BP, on the basis of {sup 14}C and {sup 13}C values, which is in agreement with the {sup 3}H concentrations being below the detection limit.

  8. Microjet flow control in an ultra-compact serpentine inlet

    Directory of Open Access Journals (Sweden)

    Da Xingya

    2015-10-01

    Full Text Available Microjets are used to control the internal flow to improve the performance of an ultra-compact serpentine inlet. A highly offset serpentine inlet with length-to-diameter ratio of 2.5 is designed and static tests are conducted to analyze the internal flow characteristics in terms of pressure recovery, distortion and flow separation. Flow separation is encountered in the second S-turn, and two strong counter-rotating vortices are formed at the aerodynamic interface plane (AIP face which occupy a quarter of the outlet area and result in severe pressure loss and distortion. A flow control model employing a row of microjets in the second turn is designed based on the internal flow characteristics and simplified CFD simulations. Flow control tests are conducted to verify the control effectiveness and understand the characteristics as a function of inlet throat Mach number, injection mass flow ratio, jet Mach number and momentum coefficient. At all test Mach numbers, microjet flow control (MFC effectively improves the recovery and reduces the distortion intensity. Between inlet throat Mach number 0.2 and 0.5, the strong flow separation in the second S-turn is suppressed at an optimum jet flow ratio of less than 0.65%, resulting in a maximum improvement of 4% for pressure recovery coefficient and a maximum decrease of 75% for circumferential distortion intensity at cruise. However, in order to suppress the flow separation, the injection rate should retain in an effective range. When the injection rate is higher than this range, the flow is degraded and the distortion contour is changed from 90° circumferential distortion pattern to 180° circumferential distortion pattern. Detailed data analysis shows that this optimum flow ratio depends on inlet throat Mach number and the momentum coefficient affects the control effectiveness in a dual stepping manner.

  9. Polyphase serpentinization history of Mariana forearc mantle: observations on the microfabric of ultramafic clasts from ODP Leg 195, Site 1200

    Science.gov (United States)

    Kahl, Wolf-Achim; Jöns, Niels; Bach, Wolfgang; Klein, Frieder

    2013-04-01

    In the forearc of the Mariana subduction zone system, a number of seamounts form from extrusion of blueschist and serpentine mud. Ocean Drilling Program Leg 195 drilled the South Chamorro seamount, where ultramafic clasts occur within the mud matrix. These clasts show a complex serpentinization history, which bears the potential for tracking the alteration history during uplift and cooling of mantle wedge rocks to the seafloor. Moreover, the microfabrics of the highly serpentinized harzburgite and dunite clasts exhibit evidence for multiple fracturing events in the forearc mantle. These, in turn, lead to fluid influx and varied styles of serpentinization of harzburgite and dunite. The serpentinized ultramafic clasts exhibit a variety of microfabrics that range from virtually undeformed to strongly deformed samples. Pervasively serpentinized harzburgites feature either an equigranular fabric of serpentinized olivine and orthopyroxene crystals, or different vein generations related to multiple stages of serpentinization. Several types of fluid pathways in harzburgites are present: (i) veins containing brucite and iron oxides, developed linearly without marked conformance with the rock fabric. In places, these veins developed mm-cm wide halos with finger-shaped serpentinization fronts. Veins of type (i) are either developed as syntaxial veins from a single crack-seal event with large magnetite crystals growing from one wall to the other (as confirmed with high-resolution X-ray microtomography), or formed by multiple fluid events. (ii) serpentine veins that encompass regions of marginally serpentinized, microgranular olivine and large orthopyroxene crystals. (iii) extensional serpentine veins (known as "Frankenstein" type). In the clasts studied, their occurrence is restricted to the halo region of type (i) veins. (iv) as a late-stage feature, extensional veins documenting multiple crack-seal events can be present in the serpentinites (either in undeformed regions with

  10. By-products of the serpentinization process on the Oman ophiolite : chemical and isotopic composition of carbonate deposits in alkaline springs, and associated secondary phases

    Science.gov (United States)

    Sissmann, O.; Martinez, I.; Deville, E.; Beaumont, V.; Pillot, D.; Prinzhofer, A.; Vacquand, C.; Chaduteau, C.; Agrinier, P.; Guyot, F. J.

    2014-12-01

    The isotopic compositions (d13C, d18O) of natural carbonates produced by the alteration of basic and ultrabasic rocks on the Oman ophiolite have been measured in order to better understand their formation mechanisms. Fossil carbonates developed on altered peridotitic samples, mostly found in fractures, and contemporary carbonates were studied. The samples bear a large range of d13C. Those collected in veins are magnesian (magnesite, dolomite) and have a carbon signature reflecting mixing of processes and important fractionation (-11‰ to 8‰). Their association with talc and lizardite suggests they are by-products of a serpentinization process, that must have occurred as a carbon-rich fluid was circulating at depth. On the other hand, the carbonates are mostly calcic when formed in alkaline springs, most of which are located in the vicinity of lithological discontinuities such as the peridotite-gabbro contact (Moho). Aragonite forms a few meters below the surface of the ponds in Mg-poor water, and is systematically associated with brucite (Mg(OH)2). This suggests most of the Mg dissolved at depth has reprecipitated during the fluid's ascension through fractures or faults as carbonates and serpentine. Further up, on the surface waters of the ponds (depleted in Mg and D.I.C.), thin calcite films precipitate and reach extremely negative d13C values (-28‰), which could reflect either a biological carbon source, or kinetic fractionation from pumping atmospheric CO2. Their formation represent an efficient and natural process for carbon dioxide mineral sequestration. The d18O signature from all samples confirm the minerals crystallized from a low-temperature fluid. The hyperalkaline conditions (pH between 11 and 12) allowing for these fast precipitation kinetics are generated by the serpentinization process occurring at depth, as indicated by the measured associated H2-rich gas flows (over 50%) seeping out to the surface.

  11. Study of phosphatic nodules as a possible source of uranium mineralization in warcha sandstone of nilawahan group salt range using SSNTD technique

    International Nuclear Information System (INIS)

    Qureshi, A.A.; Ullah, K.; Ullah, N.; Mohammad, A.

    2004-07-01

    The strong in the sedimentary depositional characteristics between the Warcha Sandstone of Nilawahan Group in the Salt Range and the uranium bearing sandstones of Siwalik Group in the foot hills of Himalaya and Sulaiman Ranges tempted the geologists to investigate the former group for the occurrence of any uranium deposits in it. Like volcanic ash beds in Siwaliks, phosphatic nodules may be a possible source of uranium mineralization in Warcha Sandstone of Nilawahan Group. Samples of phosphatic nodules occurring in the Sandstone of Nilawahan Group Salt Range were analyzed using Solid State Nuclear Track Detention Technique (SSNTD) for the determination of their uranium concentration. The results obtained are quite encouraging and favour the idea of exploring the area in detail for any possible occurrence of uranium deposit. Uranium concentration in these samples ranges from (434 + - 39) ppm to (964+ -81)ppm with and average concentration of (699 + - 62) ppm. (author)

  12. Magnetic properties of variably serpentinized peridotites and their implication for the evolution of oceanic core complexes

    NARCIS (Netherlands)

    Maffione, M.; Morris, A.; Plümper, O.|info:eu-repo/dai/nl/37155960X; van Hinsbergen, D.J.J.|info:eu-repo/dai/nl/269263624

    Serpentinization of ultramafic rocks during hydrothermal alteration at mid-ocean ridges profoundly changes the physical, chemical, rheological, and magnetic properties of the oceanic lithosphere. There is renewed interest in this process following the discovery of widespread exposures of

  13. Water removal characteristics of parallel serpentine channels. Paper no. IGEC-1-035

    International Nuclear Information System (INIS)

    Jiao, K.; Zhou, B.; Quan, P.

    2005-01-01

    Water management in a proton exchange membrane (PEM) fuel cell stack has been a challenging issue on the road to commercialization. This paper presents a numerical investigation of air-water flow in parallel serpentine channels on cathode side of a PEM fuel cell stack by use of the commercial Computational Fluid Dynamics (CFD) software package FLUENT. Different air-water flow behaviours inside the serpentine flow channels with inlet and outlet manifolds were discussed. The results showed that there were significant variations of water distribution and pressure drop in different cells at different times. The 'collecting-and-separating effect' due to the serpentine shape of the gas flow channels, the pressure drop change due to the water distribution inside the outlet manifold were observed. Several gas flow problems of this type of parallel serpentine channels were identified and useful suggestions were given through investigating the flow patterns inside the channels and manifolds. (author)

  14. Fe-Ni-bearing serpentines from the saprolite horizon of Caribbean Ni-laterite deposits: new insights from thermodynamic calculations

    Science.gov (United States)

    Villanova-de-Benavent, Cristina; Domènech, Cristina; Tauler, Esperança; Galí, Salvador; Tassara, Santiago; Proenza, Joaquín A.

    2017-10-01

    Fe-Ni-bearing serpentine from the saprolite horizon is the main Ni ores in hydrous silicate-type Ni laterites and formed by chemical weathering of partially serpentinized ultramafic rocks under tropical conditions. During lateritization, Mg, Si, and Ni are leached from the surface and transported downwards. Fe2+ is oxidized to Fe3+ and fixed as insoluble Fe-oxyhydroxides (mostly goethite) that incorporate Ni. This Ni is later leached from goethite and incorporated in secondary serpentine and garnierite. As a result, a serpentine-dominated saprolite horizon forms over the ultramafic protolith, overlapped by a Fe-oxyhydroxide-dominated limonite horizon. The serpentine from the protolith (serpentine I) is of hydrothermal origin and yields similar Ni (0.10-0.62 wt.% NiO) and lower Fe (mostly 1.37-5.81 wt.% FeO) concentrations than the primary olivine. In contrast, Fe-Ni-bearing serpentine from the saprolite (serpentine II) shows significantly higher and variable Fe and Ni contents, typically ranging from 2.23 to 15.59 wt.% Fe2O3 and from 1.30 to 7.67 wt.% NiO, suggesting that serpentine get enriched in Fe and Ni under supergene conditions. This study presents detailed mineralogical, textural, and chemical data on this serpentine II, as well as new insights by thermodynamic calculations assuming ideal solution between Fe-, Ni- and Mg-pure serpentines. The aim is to assess if at atmospheric pressure and temperature Fe-Ni-bearing serpentine can be formed by precipitation. Results indicate that the formation of serpentine II under atmospheric pressure and temperature is thermodynamically supported, and pH, Eh, and the equilibrium constant of the reaction are the parameters that affect the results more significantly.

  15. U-Pb dating of large zircons in low-temperature jadeitite from the Osayama serpentinite melange, southwest Japan: insights into the timing of serpentinization

    Science.gov (United States)

    Tsujimori, T.; Liou, J.G.; Wooden, J.; Miyamoto, T.

    2005-01-01

    Crystals of zircon up to 3 mm in length occur in jadeitite veins in the Osayama serpentinite mélange, Southwest Japan. The zircon porphyroblasts show pronounced zoning, and are characterized by both low Th/U ratios (0.2-0.8) and low Th and U abundances (Th = 1-81 ppm; U = 6-149 ppm). They contain inclusions of high-pressure minerals, including jadeite and rutile; such an occurrence indicates that the zircon crystallized during subduction-zone metamorphism. Phase equilibria and the existing fluid-inclusion data constrain P-T conditions to P > 1.2 GPa at T > 350°C for formation of the jadeitite. Most U/Pb ages obtained by SHRIMP-RG are concordant, with a weighted mean 206Pb/238U age of 472 ± 8.5 Ma (MSWD = 2.7, n = 25). Because zircon porphyroblasts contain inclusions of high-pressure minerals, the SHRIMP U-Pb age represents the timing of jadeitite formation, i.e., the timing of interaction between alkaline fluid and ultramafic rocks in a subduction zone. Although this dating does not provide a direct time constraint for serpentinization, U-Pb ages of zircon in jadeitite associated with serpentinite result in new insights into the timing of fluid-rock interaction of ultramafic rocks at a subduction zone and the minimum age for serpentinization.

  16. Hajdu-Cheney syndrome associated with serpentine fibulae and polycystic kidney disease

    International Nuclear Information System (INIS)

    Currarino, Guido

    2009-01-01

    Six patients who presented with craniofacial anomalies, musculoskeletal anomalies including elongated and bowed (serpentine) fibulae, and polycystic kidneys are reported. This association of anomalies is referred to as serpentine fibula polycystic kidney syndrome (SFPKS) and is currently interpreted as a manifestation of Hajdu-Cheney syndrome (HCS). We report a new instance of this association of anomalies and review the clinical and radiographic features of HCS and of the reported cases of SFPKS. (orig.)

  17. The H2/CH4 ratio during serpentinization cannot reliably identify biological signatures

    OpenAIRE

    Huang, Ruifang; Sun, Weidong; Liu, Jinzhong; Ding, Xing; Peng, Shaobang; Zhan, Wenhuan

    2016-01-01

    Serpentinization potentially contributes to the origin and evolution of life during early history of the Earth. Serpentinization produces molecular hydrogen (H2) that can be utilized by microorganisms to gain metabolic energy. Methane can be formed through reactions between molecular hydrogen and oxidized carbon (e.g., carbon dioxide) or through biotic processes. A simple criterion, the H2/CH4 ratio, has been proposed to differentiate abiotic from biotic methane, with values approximately lar...

  18. Serpentinization and fluid-rock interaction in Jurassic mafic and ultramafic sea-floor: constraints from Ligurian ophiolite sequences

    Science.gov (United States)

    Vogel, Monica; Früh-Green, Gretchen L.; Boschi, Chiara; Schwarzenbach, Esther M.

    2014-05-01

    The Bracco-Levanto ophiolitic complex (Eastern Liguria) represents one of the largest and better-exposed ophiolitic successions in the Northern Apennines. It is considered to be a fragment of heterogeneous Jurassic lithosphere that records tectono-magmatic and alteration histories similar to those documented along the Mid-Atlantic Ridge, such as at the 15°20'N area and the Atlantis Massif at 30°N. Structural and petrological studies on these rocks provide constraints on metamorphic/deformation processes during formation and hydrothermal alteration of the Jurassic oceanic lithosphere. We present a petrological and geochemical study of deformation processes and fluid-rock interaction in the Bracco-Levanto ophiolitic complex and compare these to modern oceanic hydrothermal systems, such as the Lost City Hydrothermal Field hosted in ultramafic rocks on the Atlantis Massif. A focus is on investigating mass transfer and fluid flow paths during high and low temperature hydrothermal activity, and on processes leading to hydrothermal carbonate precipitation and the formation of ophicalcites, which are characteristic of the Bracco-Levanto sequences. Major element and mineral compositional data allow us to distinguish a multiphase history of alteration characterized by: (1) widespread SiO2 metasomatism during progressive serpentinization, and (2) multiple phases of veining and carbonate precipitation associated with circulation of seawater and high fluid-rock ratios in the shallow ultramafic-dominated portions of the Jurassic seafloor. We observe regional variations in MgO, SiO2 and Al2O3, suggesting Si-flux towards stratigraphically higher units. In general, the ophicalcites have higher Si, Al and Fe concentrations and lower Mg than the serpentinite basement rocks or serpentinites with minimal carbonate veins. Bulk rock trace element data and Sr isotope ratios indicate seawater reacting with rocks of more mafic composition, then channeled towards stratigraphically higher

  19. The “Serpentine Syndrome” (H. Jenny, 1980: A Proxy for Soil Remediation

    Directory of Open Access Journals (Sweden)

    Claudio Bini

    2014-12-01

    Full Text Available Serpentine soils have relatively high concentrations of PTEs (Co, Cr, Cu, Fe, Ni but generally low amounts of major nutrients. They often bear a distinctive vegetation, and a frequently-used approach to understanding serpentine ecology and related environmental hazard has been the chemical analysis of soils and plants. In this paper we report past and current studies on serpentine soils and serpentinophytes. The serpentine vegetation differs from the conterminous non-serpentine areas, being often endemic, and showing macroscopic physionomical characters. Similarly, at microscopic level cytomorphological characteristics of the roots and variations in biochemical parameters were recorded in serpentinophytes. Light microscopy observations showed depressed mitotic activity in the meristematic zone, and consequent reduced root growth. The different tolerance mechanisms responsible for plant adaption to high concentrations of PTEs in serpentine soils can be related to the capacity of plants to limit metal uptake and translocation. The majority of serpentinophytes tend to limit metal absorption to roots: the cell wall constitutes a barrier against metal penetration inside plant tissues. Only a few species are able to accumulate metals in their aerial parts, acting a tolerance mechanism to very high metal concentrations. Serpentinophytes, therefore, could represent proxies for plants  used in remediation of metal-contaminated soils and in phytomining as well.

  20. Changes in plant functional groups, litter quality, and soil carbon and nitrogen mineralization with sheep grazing in an Inner Mongolian Grassland

    Science.gov (United States)

    Barger, N.N.; Ojima, D.S.; Belnap, J.; Shiping, W.; Yanfen, W.; Chen, Z.

    2004-01-01

    This study reports on changes in plant functional group composition, litter quality, and soil C and N mineralization dynamics from a 9-year sheep grazing study in Inner Mongolia. Addressed are these questions: 1) How does increasing grazing intensity affect plant community composition? 2) How does increasing grazing intensity alter soil C and N mineralization dynamics? 3) Do changes in soil C and N mineralization dynamics relate to changes in plant community composition via inputs of the quality or quantity of litter? Grazing plots were set up near the Inner Mongolia Grassland Ecosystem Research Station (IMGERS) with 5 grazing intensities: 1.3, 2.7, 4.0, 5.3, and 6.7 sheep ha -1??yr-1. Plant cover was lower with increasing grazing intensity, which was primarily due to a dramatic decline in grasses, Carex duriuscula, and Artemisia frigida. Changes in litter mass and percentage organic C resulted in lower total C in the litter layer at 4.0 and 5.3 sheep ha-1??yr-1 compared with 2.7 sheep ha -1??yr-1. Total litter N was lower at 5.3 sheep ha-1??yr-1 compared with 2.7 sheep ha -1??yr-1. Litter C:N ratios, an index of litter quality, were significantly lower at 4.0 sheep ha-1??yr -1 relative to 1.3 and 5.3 sheep ha-1??yr -1. Cumulative C mineralized after 16 days decreased with increasing grazing intensity. In contrast, net N mineralization (NH4+ + NO3-) after a 12-day incubation increased with increasing grazing intensity. Changes in C and N mineralization resulted in a narrowing of CO2-C:net Nminratios with increasing grazing intensity. Grazing explained 31% of the variability in the ratio of CO 2-C:net Nmin. The ratio of CO2-C:net N min was positively correlated with litter mass. Furthermore, there was a positive correlation between litter mass and A. frigida cover. Results suggest that as grazing intensity increases, microbes become more C limited resulting in decreased microbial growth and demand for N.

  1. Constitution of a group of Czech and French uranium miners in order to estimate lung cancer risk linked to low chronic exposure to radon decay products

    International Nuclear Information System (INIS)

    Tirmarche, M.; Tomasek, L.

    1996-01-01

    West Bohemian and French uranium miners are characterized by a long duration of exposure to radon and its decay products, in comparison to most of the other groups of miners, studied in the recent international joint analysis by the National Cancer Institute (NCI) in USA. This analysis has confirmed the linearly increasing risk of lung cancer by cumulative radon exposure, describing the different factors that may influence this dose-response relationship. One of the main factors presently discussed is the influence of the exposure-rate effect: in other words, has the same cumulated exposure spread over 10 years the same risk of lung cancer as if it is cumulated in 2 years? The implication of an inverse exposure-rate effect for low chronic exposures as well as some methodological approaches will be discussed and tested by using the data of the Czech and French cohorts. These two cohorts present annual exposures varying by a factor of 5 to 10, French exposure rates being close or even less than 0.1 Working Level during the last 20 years. The project is integrated in a larger European project on uranium miners, co-ordinated by IPSN. (author)

  2. Effects of nitrogen deposition and cattle grazing on productivity, invasion impact, and soil microbial processes in a serpentine grassland

    Science.gov (United States)

    Pasari, J.; Hernandez, D.; Selmants, P. C.; Keck, D.

    2010-12-01

    In recent decades, human activities have vastly increased the amount of biologically available nitrogen (N) in the biosphere. The resulting increase in N availability has broadly affected ecosystems through increased productivity, changes in species composition, altered nutrient cycles, and increases in invasion by exotic plant species, especially in systems that were historically low in N. California serpentine grasslands are N-limited ecosystems historically dominated by native species including several threatened and endangered plants and animals. Cattle grazing has emerged as the primary tool for controlling the impact of nitrophilic exotic grasses whose increased abundance has paralleled the regional traffic-derived increase in atmospheric N deposition. We examined the interactive effects of cattle grazing and N deposition on plant community composition, productivity, invasion resistance, and microbial processes in the Bay Area's largest serpentine grassland to determine the efficacy of current management strategies as well as the biogeochemical consequences of exotic species invasion. In the first two years of the study, aboveground net primary productivity decreased in response to grazing and increased in response to nitrogen addition. However, contrary to our hypotheses the change in productivity was not due to an increase in exotic species cover as there was little overall effect of grazing or N addition on species composition. Microbial activity was more responsive to grazing and N. Potential net N mineralization rates increased with N addition, but were not affected by grazing. In contrast, soil respiration rates were inhibited by grazing, but were not affected by N addition; suggesting strong carbon-limitation of soil microbial activity, particularly under grazing. Site differences in soil depth and grazing intensity were often more important than treatment effects. We suspect that the unusually dry conditions in the first two growing seasons inhibited

  3. Mineralogical, chemical, and crystallographic properties of supergene jarosite-group minerals from the Xitieshan Pb-Zn sulfide deposit, northern Tibetan Plateau, China

    Science.gov (United States)

    Chen, Lei; Li, Jian-Wei; Rye, Robert O.; Benzel, William H.; Lowers, H.A.; He, Ming-Zhong

    2013-01-01

    Supergene jarosite-group minerals are widespread in weathering profiles overlying Pb-Zn sulfide ores at Xitieshan, northern Tibetan Plateau, China. They consist predominantly of K-deficient natrojarosite, with lesser amounts of K-rich natrojarosite and plumbojarosite. Electron microprobe (EMP) analyses, scanning electron microcopy (SEM) investigation, and X-ray mapping reveal that the jarosite-group minerals are characterized by spectacular oscillatory zoning composed of alternating growth bands of K-deficient and K-bearing natrojarosite (K2O >1 wt.%). Plumbojarosite, whenever present, occurs as an overgrowth in the outermost bands, and its composition can be best represented by K0.29Na0.19Pb0.31Fe2.66Al0.22(SO4)1.65(PO4)0.31(AsO4)0.04(OH)7.37. The substitution of monovalent for divalent cations at the A site of plumbojarosite is charge balanced by the substitution of five-valent for six-valent anions in XO,4/sub> at the X site. Thermogravimetric analysis (TGA) of representative samples reveal mass losses of 11.46 wt.% at 446.6 °C and 21.42 wt.% at 683.4 °C due to dehydroxylation and desulfidation, respectively. TGA data also indicate that the natrojarosite structure collapses at 446.6 °C, resulting in the formation of NaFe(SO4)2 and minor hematite. The decomposition products of NaFe(SO4) are hematite and Na,2SO4. Powder X-ray diffraction (XRD) analyses show that the jarosite-group minerals have mean unit-cell parameters of a=7.315 ä and c=016.598 ä. XRD and EMP data support the view that substitutions of Na for K in the A site and full Fe occupancy in the B site can considerably decrease the unit-cell parameter c, but only slightly increase a. The results from this study suggest that the observed oscillatory zoning of jarosite-group minerals at Xitieshan resulted mainly from substitutions of K for Na at the A site and P for S at the X site.

  4. Radiation distribution through serpentine concrete using local materials and its application as a reactor biological shield

    International Nuclear Information System (INIS)

    Kansouh, W.A.

    2012-01-01

    Highlights: ► New serpentine concrete was made and examined as a reactor biological shield. ► Ilmenite–limonite concrete is a better reactor biological shield. ► New serpentine concrete is a better reactor fast neutrons shield than ordinary and hematite–serpentine concretes. ► Serpentine concrete has lower properties as a reactor total gamma rays shields. - Abstract: In the present work attempt has been made to estimate the shielding parameters of the new serpentine concrete (density = 2.4 g/cm 3 ) using local materials on the shielding parameters for two types of heat resistant concretes, namely hematite–serpentine (density = 2.5 g/cm 3 ) and ilmenite–limonite (density = 2.9 g/cm 3 ). Shielding parameters for ordinary concrete (density = 2.3 g/cm 3 ) were also discussed. These parameters were determined experimentally for serpentine concrete and compared with previously published values for other concretes, which had also been obtained using local materials. The leakage spectra of reactor fast neutrons and total gamma photon beams from cylindrical samples of these concrete shields were also investigated using a collimated beam from ET-RR-1 reactor. A neutron–gamma spectrometer was used in order to obtain pulse height spectra of reactor fast neutrons and the total gamma rays leakage through the investigated concrete samples. These spectra were utilized to obtain the energy spectra required in these investigations. Removal cross section Σ R (E n ) and linear attenuation coefficient μ(E g ) for reactor fast neutrons and total gamma rays and their relative coefficients were evaluated and presented. Measured results were compared with those previously measured for other concretes. The results show that ilmenite–limonite concrete is a better reactor biological shield than the other three concretes. Serpentine concrete under investigation is a better reactor fast neutrons shield than ordinary and hematite–serpentine concretes. Serpentine concrete

  5. Experimental investigation of As, Sb and Cs behavior during olivine serpentinization in hydrothermal alkaline systems

    Science.gov (United States)

    Lafay, Romain; Montes-Hernandez, German; Janots, Emilie; Munoz, Manuel; Auzende, Anne Line; Gehin, Antoine; Chiriac, Rodica; Proux, Olivier

    2016-04-01

    While Fluid-Mobile Elements (FMEs) such as B, Sb, Li, As or Cs are particularly concentrated in serpentinites, data on FME fluid-serpentine partitioning, distribution, and sequestration mechanisms are missing. In the present experimental study, the behavior of Sb, As and Cs during San Carlos olivine serpentinization was investigated using accurate mineralogical, geochemical, and spectroscopic characterization. Static-batch experiments were conducted at 200 °C, under saturated vapor pressure (≈1.6 MPa), for initial olivine grain sizes of coefficient increasing such as CsDp/fl = 1.5-1.6 elements are however substantially different. While the As partition coefficient remains constant throughout the serpentinization reaction, the Cs partition coefficient decreases abruptly in the first stages of the reaction to reach a constant value after the reaction is 40-60% complete. Both As and Cs partitioning appear to decrease with increasing initial olivine grain size, but there is no significant difference in the partitioning coefficient between the 30-56 and 56-150 μm grain size after complete serpentinization. X-ray absorption spectroscopy (XAS) measurements combined with X-ray chemical measurements reveal that the As(V) is mainly adsorbed onto the serpentinization products, especially brucite. In contrast, mineralogical characterization combined with XAS spectroscopy reveal redox sensitivity for Sb sequestration within serpentine products, depending on the progress of the reaction. When serpentinization is coefficient compared to that of the serpentine and brucite assemblage. Antimony reduction appears linked to water reduction accompanying the bulk iron oxidation, as half the initial Fe(II) is oxidized into Fe(III) and incorporated into the serpentine products once the reaction is over. The reduction of Sb implies a decrease of its solubility, but the type of secondary Sb-rich phases identified here might not be representative of natural systems where Sb

  6. Exergy Analysis of Serpentine Thermosyphon Solar Water Heater

    Directory of Open Access Journals (Sweden)

    Muhammad Faisal Hasan

    2018-03-01

    Full Text Available The performance of a solar hot water system is assessed for heat pump and domestic heating applications. Thermodynamic analysis on a serpentine-type thermosyphon flat-plate solar heater is conducted using the Second Law of thermodynamics. Exergetic optimization is first performed to determine the parameters for the maximum exergy efficiency using MATLAB optimization toolbox. Geometric parameters (collector surface area, dimensions, and pipe diameter, optical parameters (transmittance absorptance product, ambient temperature, solar irradiation and operating parameters (mass flow rate, fluid temperature, and overall heat transfer (loss coefficient are accounted for in the optimization scheme. The exergy efficiency at optimum condition is found to be 3.72%. The results are validated using experimental data and found to be in good agreement. The analysis is further extended to the influence of various operating parameters on the exergetic efficiency. It is observed that optical and thermal exergy losses contribute almost 20%, whereas approximately 77% exergy destruction is contributed by the thermal energy conversion. Exergy destruction due to pressure drop is found negligible. The result of this analysis can be used for designing and optimization of domestic heat pump system and hot water application.

  7. Mechanics of ultra-stretchable self-similar serpentine interconnects

    International Nuclear Information System (INIS)

    Zhang, Yihui; Fu, Haoran; Su, Yewang; Xu, Sheng

    2013-01-01

    Graphical abstract: We developed analytical models of flexibility and elastic-stretchability for self-similar interconnect. The analytic solutions agree very well with the finite element analyses, both demonstrating that the elastic-stretchability more than doubles when the order of self-similar structure increases by one. Design optimization yields 90% and 50% elastic stretchability for systems with surface filling ratios of 50% and 70% of active devices, respectively. The analytic models are useful for the development of stretchable electronics that simultaneously demand large coverage of active devices, such as stretchable photovoltaics and electronic eye-ball cameras. -- Abstract: Electrical interconnects that adopt self-similar, serpentine layouts offer exceptional levels of stretchability in systems that consist of collections of small, non-stretchable active devices in the so-called island–bridge design. This paper develops analytical models of flexibility and elastic stretchability for such structures, and establishes recursive formulae at different orders of self-similarity. The analytic solutions agree well with finite element analysis, with both demonstrating that the elastic stretchability more than doubles when the order of the self-similar structure increases by one. Design optimization yields 90% and 50% elastic stretchability for systems with surface filling ratios of 50% and 70% of active devices, respectively

  8. Flow in Rotating Serpentine Coolant Passages With Skewed Trip Strips

    Science.gov (United States)

    Tse, David G.N.; Steuber, Gary

    1996-01-01

    Laser velocimetry was utilized to map the velocity field in serpentine turbine blade cooling passages with skewed trip strips. The measurements were obtained at Reynolds and Rotation numbers of 25,000 and 0.24 to assess the influence of trips, passage curvature and Coriolis force on the flow field. The interaction of the secondary flows induced by skewed trips with the passage rotation produces a swirling vortex and a corner recirculation zone. With trips skewed at +45 deg, the secondary flows remain unaltered as the cross-flow proceeds from the passage to the turn. However, the flow characteristics at these locations differ when trips are skewed at -45 deg. Changes in the flow structure are expected to augment heat transfer, in agreement with the heat transfer measurements of Johnson, et al. The present results show that trips are skewed at -45 deg in the outward flow passage and trips are skewed at +45 deg in the inward flow passage maximize heat transfer. Details of the present measurements were related to the heat transfer measurements of Johnson, et al. to relate fluid flow and heat transfer measurements.

  9. Clay minerals assemblage in the Neogene fluvial succession of the Pishin Belt, Pakistan

    DEFF Research Database (Denmark)

    Kasi, Aimal Khan; Kassi, Akhtar Muhammad; Friis, Henrik

    2014-01-01

    indicate derivation of material from the Pre-Miocene sedimentary and meta-sedimentary terrains of the Pishin Belt. X-ray diffraction (XRD) analyses indicate that clay minerals in various mudstones and sandstone samples are identical and detrital in nature and include smectite, chlorite, illite, serpentine...... and kaolinite. Smectite and chlorite are most probably derived from the metavolcanic and mafic volcanic rocks, respectively. Presence of serpentine in samples of the Bostan Formation indicates altered ultramafic rocks as one of the source terrains. Illite is probably recycled from the older sedimentary...

  10. Testing nickel tolerance of Sorghastrum nutans and its associated soil microbial community from serpentine and prairie soils

    International Nuclear Information System (INIS)

    Doherty, Jennifer H.; Ji Baoming; Casper, Brenda B.

    2008-01-01

    Ecotypes of Sorghastrum nutans from a naturally metalliferous serpentine grassland and the tallgrass prairie were assessed for Ni tolerance and their utility in remediation of Ni-polluted soils. Plants were inoculated with serpentine arbuscular mycorrhizal (AM) root inoculum or whole soil microbial communities, originating from either prairie or serpentine, to test their effects on plant performance in the presence of Ni. Serpentine plants had marginally higher Ni tolerance as indicated by higher survival. Ni reduced plant biomass and AM root colonization for both ecotypes. The serpentine AM fungi and whole microbial community treatments decreased plant biomass relative to uninoculated plants, while the prairie microbial community had no effect. Differences in how the soil communities affect plant performance were not reflected in patterns of root colonization by AM fungi. Thus, serpentine plants may be suited for reclamation of Ni-polluted soils, but AM fungi that occur on serpentine do not improve Ni tolerance. - Ni tolerance of Sorghastrum nutans differs slightly between serpentine and prairie populations and is negatively affected by serpentine soil and root inoculation

  11. Selection of greenery plants' group tolerant to mineralized human wastes for their inclusion into intrasystem mass exchange of BTLSS

    Science.gov (United States)

    Tikhomirova, Natalia; Tikhomirov, Alexander A.; Kalacheva, Galina; Ushakova, Sofya; Trifonov, Sergey V.; Pavlova, Anastasiya

    2016-07-01

    A possible way solving the inclusion problem of the human liquid wastes containing sodium chloride into intrasystem mass exchange of bio-technical life support system (BTLSS) is selection of such species of greenery plants that can utilize sodium chloride, be edible for a human and have rather a high productivity. Our previous works showed that salt-accumulating halophyte Salicornia europaea L. was a promising candidate for sodium chloride inclusion into BTLSS mass exchange. However, with the aim of creation of more various human diet possibilities a set of greenery plants cultivated by the water culture method was estimated. Based on preliminary experiments the plants Brassica juncea L., Nasturtium officinale R. Br., Lepidium sativum angustifolia L. and Salicornia europaea L. were chosen as the investigation objects. The nutrient solution for greenery plant's cultivation was obtained after harvesting the wheat plants grown on the solution with mineralized human wastes' addition. The results of the first stage of the investigations carried out showed that plants of Brassica juncea and Lepidium sativum angustifolia are unpromising for their inclusion into BTLSS because of a set of physiological characteristics. On the next stage of investigations, an experimental model of closed ecosystem was created. For that purpose the plants of Salicornia europaea and Nasturtium officinale were introduced in the phototroph unit structure. It was determined that there was deficiency of main macronutrients for Salicornia europaea and Nasturtium officinale including sodium for Salicornia europaea. The deficiency had an effect on plants productivity and on carry-over of sodium from solution by Salicornia europaea. Thus in the future experiment it is necessary to carry out desalinization of solution by Salicornia europaea plants. Nasturtium officinale, that is rich in essential fatty acids and contributes into variety of human vegetable diet is planned to be cultivated by the

  12. Microbial and functional diversity of a subterrestrial high pH groundwater associated to serpentinization.

    Science.gov (United States)

    Tiago, Igor; Veríssimo, António

    2013-06-01

    Microbial and functional diversity were assessed, from a serpentinization-driven subterrestrial alkaline aquifer - Cabeço de Vide Aquifer (CVA) in Portugal. DGGE analyses revealed the presence of a stable microbial community. By 16S rRNA gene libraries and pyrosequencing analyses, a diverse bacterial composition was determined, contrasting with low archaeal diversity. Within Bacteria the majority of the populations were related to organisms or sequences affiliated to class Clostridia, but members of classes Acidobacteria, Actinobacteria, Alphaproteobacteria, Betaproteobacteria, Deinococci, Gammaproteobacteria and of the phyla Bacteroidetes, Chloroflexi and Nitrospira were also detected. Domain Archaea encompassed mainly sequences affiliated to Euryarchaeota. Only form I RuBisCO - cbbL was detected. Autotrophic carbon fixation via the rTCA, 3-HP and 3-HP/4H-B cycles could not be confirmed. The detected APS reductase alpha subunit - aprA sequences were phylogenetically related to sequences of sulfate-reducing bacteria belonging to Clostridia, and also to sequences of chemolithoautothrophic sulfur-oxidizing bacteria belonging to Betaproteobacteria. Sequences of methyl coenzyme M reductase - mcrA were phylogenetically affiliated to sequences belonging to Anaerobic Methanotroph group 1 (ANME-1). The populations found and the functional key markers detected in CVA suggest that metabolisms related to H2 , methane and/or sulfur may be the major driving forces in this environment. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  13. Magnetic properties of serpentinized peridotites from the Zedong ophiolite, Yarlung-Zangbo suture zone, SE Tibet

    Science.gov (United States)

    Li, Z.; Zheng, J.; Moskowitz, B. M.; Xiong, Q.; Liu, Q.

    2017-12-01

    Serpentinized mantle peridotites are widely supposed to be significant sources of the magnetic, gravity and seismic anomalies in mid-oceanic ridges, forearcs and suture zones. However, the relationship between the magnetic properties of variably serpentinized peridotites and the serpentinization process is still under debate. Ophiolite outcrops commonly comprise peridotites in different stages of serpentinization and these ophiolitic peridotites are ideal to investigate the magnetic signatures of suture zones. The Zedong ophiolite locates in the eastern part of the Yarlung-Zangbo suture zone, SE Tibet (China), and the peridotite massif represents the remnants of the Neo-Tethyan lithospheric mantle. The harzburgite and lherzolite samples show densities between 3.316 and 2.593 g cm-3, and vary from the freshest to >90% serpentinized peridotites. The magnetic susceptibility curves from room temperature to 700ºC mainly show the Curie temperatures of 585ºC for pure magnetite. The low-temperature (20-300 K) demagnetization curves show the Verwey transitions at 115-125 K, suggesting that magnetite is also the dominant remanence-carrying phase. The hysteresis data of the peridotites fall in the region of pseudo-single-domain (PSD) and follow the theoretical trends for mixtures of single domain (SD) and multidomain (MD) magnetite. The first-order reversal curve (FORC) diagrams suggest that the magnetite is dominantly interacting SD + PSD particles for S 40% serpentinized samples. The susceptibility and saturation magnetization of the Zedong peridotites range from 0.9 to 30.8 × 10‒3 (SI) and 14.1 to 1318 × 10‒3 Am2 kg‒1, respectively, and both show consistent trends with increasing degrees of serpentinization. The S serpentinization of ophiolitic peridotites, whereas the S > 40% peridotites have higher susceptibilities of 0.02-0.03 (SI) and fall in the region of abyssal peridotites. Our results suggest that the Zedong ophiolitic peridotites probably experienced a

  14. Petrology and Geochemistry of Serpentinized Peridotites from a Bonin Fore-arc Seamount

    Science.gov (United States)

    Tian, L.; Tuoyu, W.; Dong, Y. H.; Gao, J.; Wu, S.

    2016-12-01

    Serpentinites, which contain up to 13 wt.% of water, are an important reservoir for chemical recycling in subduction zones. During the last two decades, many observations documented the occurrence of fore-arc mantle serpentinites in different locations. Here, we present petrology and whole rock chemistry for serpentinized peridotites dredged from the Hahajima Seamount, which is located 20-60 km west of the junction of the Bonin Trench and the Mariana Trench. Combined with published geochemical data of serpentinites from the Torishima Seamount, Conical Seamount and South Chamorro Seamount in the Izu-Bonin-Mariana fore-arc region, it will allow us to better understand the average composition of serpentinized fore-arc mantle overlying the subducting slab and the role of serpentinized mantle playing in the subduction zone geochemical cycle. The studied ultramafic rocks from the Hahajima Seamount are extensively serpentinized and hydrated (73 to 83%), with loss of ignition values ranging between 13 and 15 wt.%. Our results show that the serpentinized peridotites have Mg number from 88 to 90, and the average MgO/SiO2 is 0.93. The average Al2O3 (0.48 wt.%) and CaO (0.23 wt.%) contents are very low, consistent with low clinopyroxene abundances, and the overall depleted character of the mantle harzburgite protoliths. The serpentinized peridotites from the Hahajima Seamount exhibit similar "U" shape rare earth element (REE) patterns ([La/Sm]N = 3.1-3.6), at higher overall abundances, to the Conical and South Chamorro Seamount suites. One exceptional sample shows the similar REE pattern as serpentinized peridotites from the Torishima Seamount, with depleted light REE concentration ([La/Sm]N =0.7). All the serpentinized peridotites from these four fore-arc seamounts show strong enrichment in fluid-mobile and lithophile elements (U, Pb, Sr and Li). The geochemical signature of the serpentinized peridotites from the seamounts in the Izu-Bonin-Mariana fore-arc region could be

  15. Transmission of neutrons in serpentine mixed and ordinary concrete a comparative study

    International Nuclear Information System (INIS)

    Ravishankar, R.; Bhattacharyya, Sarmishtha; Bandyopadhyay, Tapas; Sarkar, P.K.

    2002-01-01

    Full text: In particle accelerator facilities, for radiation shielding, concrete is commonly used for its effectiveness in attenuating neutrons in addition to its good structural and mechanical properties. Neutron attenuation depends largely on the water content in the concrete. Serpentine mixed concrete is reported to retain better water content than ordinary concrete. Experiments have been carried out to compare neutron attenuation properties of Serpentine mixed concrete slabs and ordinary concrete slabs of different thickness. Transmission of neutrons from a 185 GBq Pu-Be neutron source has been studied using NE-213 liquid scintillator detector, along with the associated electronics to discriminate neutron from gamma using pulse shape discrimination techniques. The energy differential neutron spectra transmitted through the concrete slabs and the corresponding dose have been obtained by unfolding the pulse height spectra using the FERDOR-U computer code and proper response matrix data of the NE-213 detector. The neutron transmission factors through both Serpentine and Ordinary concrete slabs have been studied. The results show serpentine mixed concrete slabs can attenuate more neutrons of varying energies compared to ordinary concrete slabs of equal dimensions. From the trend, it has been found out, with the increase in slab thickness, the gain in neutron attenuation increases. This is due to increase in quantity of serpentine with the increase in thickness of, concrete. A Monte Carlo simulation carried out, for theoretical analysis of the results, has been found to be in order

  16. Fabrication and analysis of awl-shaped serpentine microsprings for large out-of-plane displacement

    International Nuclear Information System (INIS)

    Chou, Hui-Min; Chen, Rongshun; Lin, Meng-Ju

    2015-01-01

    This work investigates a novel awl-shaped serpentine microspring for a suspension structure, with a lower spring constant under the same unit layout area in out-of-plane motion. Using Castigliano’s theorem, the spring constant of the microspring was theoretically derived and simulations were performed using COMSOL Multiphysics to verify the theoretical results. The proposed awl-shaped serpentine microspring was successfully fabricated using silicon-based micromachining. Experiments were conducted to compare the theoretical and numerical results, which were in close agreement. In addition, a parameter of spring constant to layout area ratio (K/A) is defined to be used as the index for comparing spring constants under the same unit area. Accordingly, the awl-shaped serpentine microspring has a lower K/A value than the traditional serpentine microspring with the same total effective length and folds. With a greater taper angle, more folds, a smaller beam width, and lower beam thickness, the awl-shaped serpentine microspring has a smaller K/A value. Using the proposed mathematical model, the spring constants of microsprings of various sizes and geometric structures can be calculated in out-of-plane motion before the microstructure is fabricated. Thus, it saves time when designing a microspring with a proper spring constant. (paper)

  17. Transmission of neutrons in serpentine mixed and ordinary concrete- a comparative study

    International Nuclear Information System (INIS)

    Ravishankar, R.; Bhattacharyya, Sarmishtha; Bandyopadhyay, Tapas; Sarkar, P. K.

    2002-01-01

    In particle accelerator facilities, for radiation shielding, concrete is commonly used for its effectiveness in attenuating neutrons in addition to its good structural and mechanical properties. Neutron attenuation depends largely on the water content in the concrete. Serpentine mixed concrete is reported to retain better water content than ordinary concrete. Experiments have been carried out to compare neutron attenuation properties of Serpentine mixed concrete slabs and ordinary concrete slabs of different thickness. Transmission of neutrons from a 185 GBq Pu-Be neutron source has been studied using NE-213 liquid scintillator detector, along with the associated electronics to discriminate neutron from gamma using pulse shape discrimination techniques. The energy differential neutron spectra transmitted through the concrete slabs and the corresponding dose have been obtained by unfolding the pulse height spectra using the FERDOR-U computer code and proper response matrix data of the NE-213 detector. The neutron transmission factors through both Serpentine and Ordinary concrete slabs have been studied. The results show serpentine mixed concrete slabs can attenuate more neutrons of varying energies compared to ordinary concrete slabs of equal dimensions. From the trend, it has been found out, with the increase in slab thickness, the gain in neutron attenuation increases. This is due to increase in quantity of serpentine with the increase in thickness of concrete. A Monte Carlo simulation carried out, for theoretical analysis of the results, has been found to be in order

  18. Vestiges of Submarine Serpentinization Recorded in the Microbiology of Continental Ophiolite Complexes

    Science.gov (United States)

    Schrenk, M. O.; Sabuda, M.; Brazelton, W. J.; Twing, K. I.

    2017-12-01

    The study of serpentinization-influenced microbial ecosystems at and below the seafloor has accelerated in recent years with multidisciplinary drilling expeditions to the Atlantis Massif (X357), Southwest Indian Ridge (X360) and Mariana Forearc (X366). In parallel, a number of studies have surveyed serpentinizing systems in ophiolite complexes which host a range of geologic histories, geochemical characteristics, fluid pathways, and consequently microbiology. As ophiolite complexes originate as seafloor materials, it is likely that a microbiological record of seafloor serpentinization processes is maintained through the emplacement and weathering of continental serpentinites. This hypothesis was evaluated through a global comparison of continental serpentinite springs and groundwater, ranging from highly brackish (saline) to freshwater. One of the most saline sites, known as the Coast Range Ophiolite Microbial Observatory (CROMO), was used as a point-of-comparison to marine serpentinizing systems, such as the Lost City Hydrothermal Field. Although there was little taxonomic overlap between microbial populations in marine and terrestrial systems, both communities harbored an abundance of genes involved in sulfur metabolism, including sulfide oxidation, thiosulfate disproportionation, and sulfate reduction. The phylogeny of key genes involved in these metabolic processes was evaluated relative to published studies and compared between sites. Together, these data provide insights into both the functioning of microbial communities in modern-day serpentinizing systems, and the transport processes that disperse microorganisms between marine and terrestrial serpentinites.

  19. Serpentinization and the origin of hydrogen gas in Kansas

    Energy Technology Data Exchange (ETDEWEB)

    Coveney, R.M. Jr.; Goebel, E.D.; Zeller, E.J.; Dreschhoff, G.A.M.; Angino, E.E.

    1987-01-01

    Hydrogen gas occurs in ten Kansas wells near the Mid-Continent rift system. Since 1982, two wells have yielded small amounts of gases containing an average of 29-37 mole % H/sub 2/, the remainder being chiefly N/sub 2/ with only traces of hydrocarbons. Isotopic compositions for hydrogen (delta D = -740 to -836 per thousand) imply near-ambient (about 10/sup 0/C) equilibration temperatures for the gases, which are among the most deuterium-depleted in nature and resemble the H/sub 2/-rich gases described from ophiolites in Oman. Isotopic values for the Kansas N/sub 2/ differ slightly from those of the atmosphere, but not enough to rule out an atmospheric origin. Because they are low in CH/sub 4/ and CO/sub 2/, expected byproducts of biogenic activity, the gases are probably abiogenic in origin. The existence of such gases near a major rift system, containing mafic rocks, and not far from known kimberlites is consistent with an origin from reactions involving Fe/sup +2/ oxidation, for example during serpentinization. Because the gases may be associated with kimberlites and deep-seated rifting, mantle outgassing is possible, but such an origin would be difficult to reconcile with the low isotopic temperatures. The H/sub 2/ gases from Kansas (and elsewhere) seem to be too low in pressure to have commercial value. However, neither the Kansas gases nor those from other H/sub 2/ occurrences have been adequately examined to assess their importance as potential resources. 4 figures, 3 tables.

  20. Bringing together evolution on serpentine and polyploidy: spatiotemporal history of the diploid-tetraploid complex of Knautia arvensis (Dipsacaceae.

    Directory of Open Access Journals (Sweden)

    Filip Kolář

    Full Text Available Polyploidization is one of the leading forces in the evolution of land plants, providing opportunities for instant speciation and rapid gain of evolutionary novelties. Highly selective conditions of serpentine environments act as an important evolutionary trigger that can be involved in various speciation processes. Whereas the significance of both edaphic speciation on serpentine and polyploidy is widely acknowledged in plant evolution, the links between polyploid evolution and serpentine differentiation have not yet been examined. To fill this gap, we investigated the evolutionary history of the perennial herb Knautia arvensis (Dipsacaceae, a diploid-tetraploid complex that exhibits an intriguing pattern of eco-geographic differentiation. Using plastid DNA sequencing and AFLP genotyping of 336 previously cytotyped individuals from 40 populations from central Europe, we unravelled the patterns of genetic variation among the cytotypes and the edaphic types. Diploids showed the highest levels of genetic differentiation, likely as a result of long term persistence of several lineages in ecologically distinct refugia and/or independent immigration. Recurrent polyploidization, recorded in one serpentine island, seems to have opened new possibilities for the local serpentine genotype. Unlike diploids, the serpentine tetraploids were able to escape from the serpentine refugium and spread further; this was also attributable to hybridization with the neighbouring non-serpentine tetraploid lineages. The spatiotemporal history of K. arvensis allows tracing the interplay of polyploid evolution and ecological divergence on serpentine, resulting in a complex evolutionary pattern. Isolated serpentine outcrops can act as evolutionary capacitors, preserving distinct karyological and genetic diversity. The serpentine lineages, however, may not represent evolutionary 'dead-ends' but rather dynamic systems with a potential to further influence the surrounding

  1. Serpentinization of mantle-derived peridotites at mid-ocean ridges: Mesh texture development in the context of tectonic exhumation

    Science.gov (United States)

    Rouméjon, Stéphane; Cannat, Mathilde

    2014-06-01

    At slow spreading ridges, axial detachment faults exhume mantle-derived peridotites and hydrothermal alteration causes serpentinization in a domain extending more than 1 km next to the fault. At the microscopic scale, serpentinization progresses from a microfracture network toward the center of olivine relicts and forms a mesh texture. We present a petrographic study (SEM, EBSD, and Raman) of the serpentine mesh texture in a set of 278 abyssal serpentinized peridotites from the Mid-Atlantic and Southwest Indian Ridges. We show that serpentinization initiated along two intersecting sets of microfractures that have consistent orientations at the sample scale, and in at least one studied location, at the 100 m scale. We propose that these microfractures formed in fresh peridotites due to combined thermal and tectonic stresses and subsequently served as channels for serpentinizing fluids. Additional reaction-induced cracks developed for serpentinization extents <20%. The resulting microfracture network has a typical spacing of ˜60 µm but most serpentinization occurs next to a subset of these microfractures that define mesh cells 100-400 µm in size. Apparent mesh rim thickness is on average 33 ± 19 µm corresponding to serpentinization extents of 70-80%. Published laboratory experiments suggest that mesh rims formation could be completed in a few years (i.e., quasi instantaneous at the plate tectonic timescale). The depth and extent of the serpentinization domain in the detachment fault's footwall are probably variable in time and space and as a result we expect that the serpentine mesh texture at slow spreading ridges forms at variable rates with a spatially heterogeneous distribution.

  2. Determination of mineral constituents in duplicate portion diets of two university student groups by instrumental neutron activation

    International Nuclear Information System (INIS)

    Maihara, V.A.; Favaro, D.I.T.; Silva, V.N.; Cunha, I.I.L.; Vasconcellos, M.B.A.; Gonzaga, I.B.; Silva, V.L.; Cozzolino, S.M.F.

    2001-01-01

    Concentrations of 15 elements were determined simultaneously in duplicate portion diets of two university student groups from Sao Paulo University consisting of nine women (20-23 years) and ten men (20-24 years). The diet samples were prepared by either freeze-drying or drying in a ventilated oven. About 100-200 mg of diets were irradiated for 2 minutes and 8 hours in the IEA-R1 m research reactor and Br, Ca, Cl, Co, Cr, Cs, K, Fe, Mn, Mg, Mo, Na, Rb, Se, and Zn were determined by instrumental neutron activation analysis (INAA). The average daily intakes found in the women and men groups were: 2.1 and 4.3 mg of Br, 501 and 707 mg of Ca; 3.1 and 6.0g of Cl; 12 and 25 mg of Co; 15 and 36μg of Cs; 53 and 63μg of Cr; 5.1 and 10.8 mg of Fe; 1.3 and 2.8 g of K; 134 and 306 mg of Mg; 1,3 and 4.1 mg of Mn; 134 and 302 mg of Mo, 2.0 and 4.1 g of Na; 2.4 and 4.6 mg of Rb; 29 and 41μg of Se; 6.2 and 10.6 mg of Zn, respectively. The daily intakes of Ca, Se and Zn in both groups and Fe in the women groups appeared to be below the U.S. RDA recommendations. For the elements Na and Cl the daily intakes were higher than the recommended values by RDA. (author)

  3. Activation of magnesium rich minerals as carbonation feedstock materials for CO2 sequestration

    International Nuclear Information System (INIS)

    Maroto-Valer, M.M.; Kuchta, M.E.; Zhang, Y.; Andresen, J.M.; Fauth, D.J.

    2005-01-01

    Mineral carbonation, the reaction of magnesium-rich minerals such as olivine and serpentine with CO 2 to form stable mineral carbonates, is a novel and promising approach to carbon sequestration. However, the preparation of the minerals prior to carbonation can be energy intensive, where some current studies have been exploring extensive pulverization of the minerals below 37 μm, heat treatment of minerals up to 650 o C, prior separation of CO 2 from flue gases, and carbonation at high pressures, temperatures and long reaction times of up to 125 atm, 185 o C and 6 h, respectively. Thus, the objective of the mineral activation concept is to promote and accelerate carbonation reaction rates and efficiencies through surface activation to the extent that such rigorous reaction conditions were not required. The physical activations were performed with air and steam, while chemical activations were performed with a suite of acids and bases. The parent serpentine, activated serpentines, and carbonation products were characterized to determine their surface properties and assess their potential as carbonation minerals. The results indicate that the surface area of the raw serpentine, which is approximately 8 m 2 /g, can be increased through physical and chemical activation methods to over 330 m 2 /g. The chemical activations were more effective than the physical activations at increasing the surface area, with the 650 o C steam activated serpentine presenting a surface area of only 17 m 2 /g. Sulfuric acid was the most effective acid used during the chemical activations, resulting in surface areas greater than 330 m 2 /g. Several of the samples produced underwent varying degrees of carbonation. The steam activated serpentine underwent a 60% conversion to magnesite at 155 o C and 126 atm in 1 h, while the parent sample only exhibited a 7% conversion. The most promising results came from the carbonation of the extracted Mg(OH) 2 solution, where, based on the amount of

  4. Contents of several elements in trees grown on the serpentine soil

    International Nuclear Information System (INIS)

    Tomita, Michio; Katayama, Yukio; Takada, Jitsuya; Nishimura, Kazuo.

    1990-01-01

    Determination of Mg-, Ca-, Cr-, Mn-, Fe- and Ni-content in akamatsu (P. densiflora), konara (Q. serrata) and ryoubu (C. barbinervis) which were grown on the serpentine soil, as well as in soil, were performed by the neutron activation method or the atomic absorption spectrophotometry. It turned out that contents of these elements was higher in leaves than wood. It was also found that Ni content in the leaves of konara as well as of ryoubu reflected the concentration of the acid extractable Ni in the serpentine soil. The elemental contents in akamatsu leaves were heavily affected by the characteristic contents of the serpentine soil. It is suggested that these trees are available for the indicator of soil-environment. (author)

  5. Physiological and genomic features of highly alkaliphilic hydrogen-utilizing Betaproteobacteria from a continental serpentinizing site.

    Science.gov (United States)

    Suzuki, Shino; Kuenen, J Gijs; Schipper, Kira; van der Velde, Suzanne; Ishii, Shun'ichi; Wu, Angela; Sorokin, Dimitry Y; Tenney, Aaron; Meng, XianYing; Morrill, Penny L; Kamagata, Yoichi; Muyzer, Gerard; Nealson, Kenneth H

    2014-05-21

    Serpentinization, or the aqueous alteration of ultramafic rocks, results in challenging environments for life in continental sites due to the combination of extremely high pH, low salinity and lack of obvious electron acceptors and carbon sources. Nevertheless, certain Betaproteobacteria have been frequently observed in such environments. Here we describe physiological and genomic features of three related Betaproteobacterial strains isolated from highly alkaline (pH 11.6) serpentinizing springs at The Cedars, California. All three strains are obligate alkaliphiles with an optimum for growth at pH 11 and are capable of autotrophic growth with hydrogen, calcium carbonate and oxygen. The three strains exhibit differences, however, regarding the utilization of organic carbon and electron acceptors. Their global distribution and physiological, genomic and transcriptomic characteristics indicate that the strains are adapted to the alkaline and calcium-rich environments represented by the terrestrial serpentinizing ecosystems. We propose placing these strains in a new genus 'Serpentinomonas'.

  6. Serpentine Robot Model and Gait Design Using Autodesk Inventor and Simulink SimMechanics

    Science.gov (United States)

    Daniel; Iman Alamsyah, Mohammad; Erwin; Tan, Sofyan

    2014-03-01

    The authors introduce gaits of a serpentine robot with linear expansion mechanism where the robot varies its length using joints with three degrees of freedom. The 3D model of the serpentine robot is drawed in Autocad Inventor® and exported to SimMechanics® for straighforward modeling of the kinematics. The gaits are important for robots designed to explore ruins of disasters where the working spaces are very tight. For maximum flexibility of the serpentine robot, we adopted a joint design with three parallel actuators, where the joint is capable of linear movement in the forward axis, and rotational movements around two other axes. The designed linear expansion gaits is calculated for forward movement when the robot is posing straight or turning laterally.

  7. Serpentine Robot Model and Gait Design Using Autodesk Inventor and Simulink SimMechanics

    Directory of Open Access Journals (Sweden)

    Daniel

    2014-03-01

    Full Text Available The authors introduce gaits of a serpentine robot with linear expansion mechanism where the robot varies its length using joints with three degrees of freedom. The 3D model of the serpentine robot is drawed in Autocad Inventor® and exported to SimMechanics® for straighforward modeling of the kinematics. The gaits are important for robots designed to explore ruins of disasters where the working spaces are very tight. For maximum flexibility of the serpentine robot, we adopted a joint design with three parallel actuators, where the joint is capable of linear movement in the forward axis, and rotational movements around two other axes. The designed linear expansion gaits is calculated for forward movement when the robot is posing straight or turning laterally.

  8. CO2 emissions: mineral carbonation and Finnish pulp and paper industry (CO2 Nordic Plus) and use of serpentinites in energy and metal industry (ECOSERP)

    International Nuclear Information System (INIS)

    Fogelholm, C.-J.; Raiski, T.; Teir, S.

    2007-01-01

    Abstract Mineral carbonation has been investigated at Helsinki University of Technology (TKK), laboratory of energy engineering and environmental protection since year 2000. The Finnish Technology Agency Tekes and the Finnish Recovery Boiler Committee are funding through the ClimBus technology programme, in conjunction with the Nordic Energy Research Programme, the research regarding the application of ex situ mineral carbonation processes. One aspect is to verify the possible use of mineral carbonation for the separation, utilisation and long-term storage of carbon dioxide (CO 2 ) in the pulp and paper industry. The Geological Survey of Finland (GTK) has been screening since 2004 the location, quality and suitability of the Finnish processed serpentine and stoped serpentinite storage of mines and in situ serpentinite bodies of ultramafic rock formations for mineral carbonation of CO 2 . Tekes and the GTK are funding development work through the ClimBus technology programme on the utilisation of serpentine and serpentinite for CO 2 sequestration purposes, based on economical and environmental evaluation of mineral and mining processing operations. Also the options for other use of serpentine and serpentinite are evaluated. The most promising magnesium- and calcium-based sources for carbonation are by-products of mining processes of ultramafic rocks (such as serpentinites and serpentine) and steelmaking slags. Carbonated minerals could possibly be used as paper coating materials (PCC), fillers or construction materials. For magnesium carbonate new markets and applications must be developed. (orig.)

  9. CO2 emissions: mineral carbonation and Finnish pulp and paper industry (CONordicPlus) and use of serpentinites in energy and metal industry (ECOSERP)

    International Nuclear Information System (INIS)

    Fogelholm, C.J.; Raiski, T.; Teir, S.

    2006-01-01

    Mineral carbonation has been investigated at Helsinki University of Technology (TKK), laboratory of energy engineering and environmental protection since year 2000. The Finnish Technology Agency Tekes and the Finnish Recovery Boiler Committee are funding through the ClimBus technology programme, in conjunction with the Nordic Energy Research Programme, the research regarding the application of ex situ mineral carbonation processes. One aspect is to verify the possible use of mineral carbonation for the separation, utilisation and long-term storage of carbon dioxide (CO2) in the pulp and paper industry. The Geological Survey of Finland (GTK) has been screening since 2004 the location, quality and suitability of the Finnish processed serpentine and stopped serpentinite storage of mines and in situ serpentinite bodies of ultramafic rock formations for mineral carbonation of CO2. Tekes and the GTK are funding development work through the ClimBus technology programme on the utilisation of serpentine and serpentinite for CO2 sequestration purposes, based on economical and environmental evaluation of mineral and mining processing operations. Also the options for other use of serpentine and serpentinite are evaluated. The most promising magnesium and calcium-based sources for carbonation are by products of mining processes of ultramafic rocks (such as serpentinites and serpentine) and steelmaking slags. Carbonated minerals could possibly be used as paper coating materials (PCC), fillers or construction materials. For magnesium carbonate new markets and applications must be developed. (orig.)

  10. Electron beam irradiation induces abnormal development and the stabilization of p53 protein of American serpentine leafminer, Liriomyza trifolii (Burgess)

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Hyun-Na; Yun, Seung-Hwan; Yoon, Changmann [Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kim, Gil-Hah, E-mail: khkim@chungbuk.ac.kr [Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)

    2012-01-15

    The American serpentine leafminer fly, Liriomyza trifolii (Burgess), is one of the most destructive polyphagous pests worldwide. In this study, we determined electron beam doses for inhibition of normal development of the leaf miner and investigated the effect of electron beam irradiation on DNA damage and p53 stability. Eggs (0-24 h old), larvae (2nd instar), puparia (0-24 h old after pupariation) and adults (24 h after emergence) were irradiated with increasing doses of electron beam irradiation (six levels between 30 and 200 Gy). At 150 Gy, the number of adults that developed from irradiated eggs, larvae and puparia was lower than in the untreated control. Fecundity and egg hatchability decreased depending on the doses applied. Reciprocal crosses between irradiated and unirradiated flies demonstrated that males were more radiotolerant than females. Adult longevity was not affected in all stages. The levels of DNA damage in L. trifolii adults were evaluated using the alkaline comet assay. Our results indicate that electron beam irradiation increased levels of DNA damage in a dose-dependent manner. Moreover, low doses of electron beam irradiation led to the rapid appearance of p53 protein within 6 h; however, it decreased after exposure to high doses (150 Gy and 200 Gy). These results suggest that electron beam irradiation induced not only abnormal development and reproduction but also p53 stability caused by DNA damage in L. trifolii. We conclude that a minimum dose of 150 Gy should be sufficient for female sterilization of L. trifolii. - Highlights: > Electron beam irradiation inhibited normal development of the leaf miner. > Electron beam irradiation inhibited normal reproduction of the leaf miner. > Electron beam irradiation increased levels of DNA damage. > Electron beam irradiation induced p53 stability.

  11. The association between body composition, 25(OH)D, and PTH and bone mineral density in black African and Asian Indian population groups.

    Science.gov (United States)

    George, Jaya A; Micklesfield, L K; Norris, S A; Crowther, N J

    2014-06-01

    There are few data on the contribution of body composition to bone mineral density (BMD) in non-Caucasian populations. We therefore studied the contribution of body composition, and possible confounding of 25-hydroxyvitamin D and PTH, to BMD at various skeletal sites in black African (BA) and Asian Indian (AI) subjects. This was a cross-sectional study in Johannesburg, South Africa. BMD, body fat, and lean mass were measured using dual x-ray absorptiometry and abdominal fat distribution by ultrasound in 714 healthy subjects, aged 18-65 years. Whole-body (subtotal), hip, femoral neck, and lumbar spine (lumbar) BMD were significantly higher in BA than AI subjects (P < .001 for all). Whole-body lean mass positively associated with BMD at all sites in both ethnic groups (P < .001 for all) and partially explained the higher BMD in BA females compared with AI females. Whole-body fat mass correlated positively with lumbar BMD in BA (P = .001) and inversely with subtotal BMD in AI subjects (P < .0001). Visceral adiposity correlated inversely with subtotal BMD in the BA (P = .037) and with lumbar BMD in the AI group (P = .005). No association was found between serum 25-hydroxyvitamin D and BMD. PTH was inversely associated with hip BMD in the BA group (P = .01) and with subtotal (P = .002), hip (P = .001), and femoral BMD (P < .0001) in the AI group. Significant differences in whole-body and site-specific BMD between the BA and AI groups were observed, with lean mass the major contributor to BMD at all sites in both groups. The contribution of other components of body composition differed by site and ethnic group.

  12. The mineral economy of Brazil--Economia mineral do Brasil

    Science.gov (United States)

    Gurmendi, Alfredo C.; Barboza, Frederico Lopes; Thorman, Charles H.

    1999-01-01

    This study depicts the Brazilian government structure, mineral legislation and investment policy, taxation, foreign investment policies, environmental laws and regulations, and conditions in which the mineral industry operates. The report underlines Brazil's large and diversified mineral endowment. A total of 37 mineral commodities, or groups of closely related commodities, is discussed. An overview of the geologic setting of the major mineral deposits is presented. This report is presented in English and Portuguese in pdf format.

  13. Preserved organic matter in the Serpentinized Ocean-Continent Transition of Alpine Tethys

    Science.gov (United States)

    Mateeva, T.; Wolff, G. A.; Kusznir, N.; Manatschal, G.; Wheeler, J.

    2017-12-01

    Serpentinization occurs at slow-spreading ocean ridges and magma-poor rifted continental margins. At modern hydrothermal vents, serpentinization has been observed to support hydrogen-driven microbial environments including methanotrophic biosystems. An important question is: "Are such bio-systems locally restricted to hydrothermal vents or are they more pervasive, being linked with the exhumation of serpentinized mantle at the seafloor?" Fieldwork sampling of km scale exposures of orogenically exhumed serpentinized mantle in the Alps allows 3D mantle sampling that is not possible at ocean ridges and provides an opportunity to investigate the organic matter in an ophiolite sequence relative to the seafloor. Samples from the fossil Tethyan OCT, exhumed during Alpine collisional orogeny, have been examined for the presence or absence of biomarkers typical of methanotrophy within serpentinized exhumed mantle. Samples from the Totalp unit, Tasna nappe and Platta unit of the Eastern Swiss Alps and Chenaillet in the Western Alps from the Tethyan magma-poor OCT were selected for analysis because they have little Alpine deformation and underwent only low-grade Alpine metamorphism. Hand specimens and cores taken from these locations have been analysed to search for the presence or absence of biomarkers in the serpentinite and its overlying lithologies. Thin sections of samples from these OCT locations reveal multiple serpentinization events and calcification phases. All the lithologies sampled show the presence of hydrocarbons such as n-alkanes, low molecular weight polynuclear aromatic hydrocarbons (PAHs, of mixed petrogenic and pyrogenic source), hopanes, steranes (of marine origin), and branched alkanes (pristane and phytane, non-specific marine origin). The identifiable biomarkers and the isotopic data are consistent with organic matter of a marine origin and do not provide any evidence for a methanotrophic bio-system. It is noteworthy that basement mantle rocks still

  14. Repairing the deteriorated thermal insulation in the serpentine - moderator tank - SLCD assemblies

    International Nuclear Information System (INIS)

    Gyongyosi, Tiberiu

    2004-01-01

    Deterioration during operation of the thermal insulation at the upper serpentines in the serpentine assembly in the moderator tank of SLCD (the system of localising the failed fuel) can create problems when one scans the fuel channels in case of failure of one of the ventilated air refrigerator in the rooms of the LAC 10 reactor. Recovering the thermal insulation is absolutely necessary but it is difficult to execute because the loading operation with the granulated layer of diatomaceous filtering agent must be effected directly on the moderator tank after some 24 h from the reactor shut down. The paper presents two possible methods of repairing together with the necessary technological facilities

  15. Visual study of air--water mixtures flowing inside serpentine tubes

    International Nuclear Information System (INIS)

    Farukhi, M.N.; Parker, J.D.

    1974-01-01

    Hydrodynamic behavior of air-water mixtures flowing inside serpentine tubes, with bends in the vertical plane, was investigated. Flow visualization was accomplished by injecting dye into the liquid phase and recording the events on color slides and color movies. For certain combinations of gas and liquid flow rates, in the annular type flow regime, ''film inversion'' was observed in the bend as well as in the straight section immediately downstream of the bend. A new flow regime map particularly applicable to two phase flow inside serpentine tubes is presented. (U.S.)

  16. Inertial particle focusing in serpentine channels on a centrifugal platform

    Science.gov (United States)

    Shamloo, Amir; Mashhadian, Ali

    2018-01-01

    Inertial particle focusing as a powerful passive method is widely used in diagnostic test devices. It is common to use a curved channel in this approach to achieve particle focusing through balancing of the secondary flow drag force and the inertial lift force. Here, we present a focusing device on a disk based on the interaction of secondary flow drag force, inertial lift force, and centrifugal forces to focus particles. By choosing a channel whose cross section has a low aspect ratio, the mixing effect of the secondary flow becomes negligible. To calculate inertial lift force, which is exerted on the particle from the fluid, the interaction between the fluid and particle is investigated accurately through implementation of 3D Direct Numerical Solution (DNS) method. The particle focusing in three serpentine channels with different corner angles of 75°, 85°, and 90° is investigated for three polystyrene particles with diameters of 8 μm, 9.9 μm, and 13 μm. To show the simulation reliability, the results obtained from the simulations of two examples, namely, particle focusing and centrifugal platform, are verified against experimental counterparts. The effects of angular velocity of disk on the fluid velocity and on the focusing parameters are studied. Fluid velocity in a channel with corner angle of 75° is greater than two other channels. Furthermore, the particle equilibrium positions at the cross section of channel are obtained at the outlet. There are two equilibrium positions located at the centers of the long walls. Finally, the effect of particle density on the focusing length is investigated. A particle with a higher density and larger diameter is focused in a shorter length of the channel compared to its counterpart with a lower density and shorter diameter. The channel with a corner angle of 90° has better focusing efficiency compared to other channels. This design focuses particles without using any pump or sheath flow. Inertial particle focusing

  17. Estimated intake of the sweeteners, acesulfame-K and aspartame, from soft drinks, soft drinks based on mineral waters and nectars for a group of Portuguese teenage students.

    Science.gov (United States)

    Lino, C M; Costa, I M; Pena, A; Ferreira, R; Cardoso, S M

    2008-11-01

    In a survey of levels of acesulfame-K and aspartame in soft drinks and in light nectars, the intake of these intense sweeteners was estimated for a group of teenage students. Acesulfame-K was detected in 72% of the soft drinks, with a mean concentration of 72 mg l(-1) and aspartame was found in 92% of the samples with a mean concentration of 89 mg l(-1). When data on the content of these sweeteners in soft drinks were analysed according to flavour, cola drinks had the highest mean levels for both sweeteners with 98 and 103 mg l(-1) for acesulfame-K and aspartame, respectively. For soft drinks based on mineral water, aspartame was found in 62% of the samples, with a mean concentration of 82 mg l(-1) and acesulfame-K was found in 77%, with a mean level of 48 mg l(-1). All samples of nectars contained acesulfame-K, with a mean concentration of 128 mg l(-1) and aspartame was detected in 80% of the samples with a mean concentration of 73 mg l(-1). A frequency questionnaire, designed to identify adolescents having high consumption of these drinks, was completed by a randomly selected sample of teenagers (n = 65) living in the city of Coimbra, in 2007. The estimated daily intakes (EDI) of acesulfame-K and aspartame for the average consumer were below the acceptable daily intakes (ADIs). For acesulfame-K, the EDI was 0.7 mg kg(-1) bw day(-1) for soft drinks, 0.2 mg kg(-1) bw day(-1) for soft drinks based on mineral waters, and 0.5 mg kg(-1) bw day(-1) for nectars, representing 8.0%, 2.2%, and 5.8% of the ADI, respectively. A similar situation was observed for aspartame. In this way, the EDI for soft drinks was 1.1 mg kg(-1) day(-1), representing only 2.9% of the ADI. In respect of nectars, the EDI was 0.2 mg kg(-1) bw day(-1), representing 0.5% of the ADI. Soft drinks based on mineral waters showed the lowest EDI values of 0.3 mg kg(-1) bw day(-1), accounting for 0.7% of the ADI.

  18. Chemistry of a serpentinization-controlled hydrothermal system at the Lost City hydrothermal vent field

    Science.gov (United States)

    Ludwig, K. A.; Kelley, D. S.; Butterfield, D. A.; Nelson, B. K.; Karson, J. A.

    2003-12-01

    The Lost City Hydrothermal Field (LCHF), at 30° N near the Mid-Atlantic Ridge, is an off-axis, low temperature, high-pH, ultramafic-hosted vent system. Within the field, carbonate chimneys tower up to 60 m above the seafloor, making them the tallest vent structures known. The chemistry of the vent structures and fluids at the LCHF is controlled by reactions between seawater and ultramafic rocks beneath the Atlantis massif. Mixing of warm alkaline vent fluids with seawater causes precipitation of calcium carbonate and growth of the edifaces, which range from tall, graceful pinnacles to fragile flanges and colloform deposits. Geochemical and petrological analyses of the carbonate rocks reveal distinct differences between the active and extinct structures. Actively venting chimneys and flanges are extremely porous, friable formations composed predominantly of aragonite and brucite. These structures provide important niches for well-developed microbial communities that thrive on and within the chimney walls. Some of the active chimneys may also contain the mineral ikaite, an unstable, hydrated form of calcium carbonate. TIMS and ICP-MS analyses of the carbonate chimneys show that the most active chimneys have low Sr isotope values and that they are low in trace metals (e.g., Mn, Ti, Pb). Active structures emit high-pH, low-Mg fluids at 40-90° C. The fluids also have low Sr values, indicating circulation of hydrothermal solutions through the serpentinite bedrock beneath the field. In contrast to the active structures, extinct chimneys are less porous, are well lithified, and they are composed predominantly of calcite that yields Sr isotopes near seawater values. Prolonged lower temperature seawater-hydrothermal fluid interaction within the chimneys results in the conversion of aragonite to calcite and in the enrichment of some trace metals (e.g., Mn, Ti, Co, Zn). It also promotes the incorporation of foraminifera within the outer, cemented walls of the carbonate

  19. Evaluating minerals of environmental concern using spectroscopy

    Science.gov (United States)

    Swayze, G.A.; Clark, R.N.; Higgins, C.T.; Kokaly, R.F.; Livo, K. Eric; Hoefen, T.M.; Ong, C.; Kruse, F.A.

    2006-01-01

    Imaging spectroscopy has been successfully used to aid researchers in characterizing potential environmental impacts posed by acid-rock drainage, ore-processing dust on mangroves, and asbestos in serpentine mineral deposits and urban dust. Many of these applications synergistically combine field spectroscopy with remote sensing data, thus allowing more-precise data calibration, spectral analysis of the data, and verification of mapping. The increased accuracy makes these environmental evaluation tools efficient because they can be used to focus field work on those areas most critical to the research effort. The use of spectroscopy to evaluate minerals of environmental concern pushes current imaging spectrometer technology to its limits; we present laboratory results that indicate the direction for future designs of imaging spectrometers.

  20. Batisivite, V8Ti6[Ba(Si2O)]O28, a new mineral species from the derbylite group

    Science.gov (United States)

    Reznitsky, L. Z.; Sklyarov, E. V.; Armbruster, T.; Galuskin, E. V.; Ushchapovskaya, Z. F.; Polekhovsky, Yu. S.; Karmanov, N. S.; Kashaev, A. A.; Barash, I. G.

    2008-12-01

    Batisivite has been found as an accessory mineral in the Cr-V-bearing quartz-diopside metamorphic rocks of the Slyudyanka Complex in the southern Baikal region, Russia. A new mineral was named after the major cations in its ideal formula (Ba, Ti, Si, V). Associated minerals are quartz, Cr-V-bearing diopside and tremolite; calcite; schreyerite; berdesinskiite; ankangite; V-bearing titanite; minerals of the chromite-coulsonite, eskolaite-karelianite, dravite-vanadiumdravite, and chernykhite-roscoelite series; uraninite; Cr-bearing goldmanite; albite; barite; zircon; and unnamed U-Ti-V-Cr phases. Batisivite occurs as anhedral grains up to 0.15-0.20 mm in size, without visible cleavage and parting. The new mineral is brittle, with conchoidal fracture. Observed by the naked eye, the mineral is black and opaque, with a black streak and resinous luster. Batisivite is white in reflected light. The microhardness (VHN) is 1220-1470 kg/mm2 (load is 30 g), the mean value is 1330 kg/mm2. The Mohs hardness is near 7. The calculated density is 4.62 g/cm3. The new mineral is weakly anisotropic and bireflected. The measured values of reflectance are as follows (λ, nm— R {max/'}/ R {min/'}): 440—17.5/17.0; 460—17.3/16.7; 480—17.1/16.5; 500—17.2/16.6; 520—17.3/16.7; 540—17.4/16.8; 560—17.5/16.8; 580—17.6/16.9; 600—17.7/17.1; 620—17.7/17.1; 640—17.8/17.1; 660—17.9/17.2; 680—18.0/17.3; 700—18.1/17.4. Batisivite is triclinic, space group P overline 1 ; the unit-cell dimensions are: a = 7.521(1) Å, b = 7.643(1) Å, c = 9.572(1) Å, α = 110.20°(1), β = 103.34°(1), γ = 98.28°(1), V = 487.14(7) Å3, Z = 1. The strongest reflections in the X-ray powder diffraction pattern [ d, Å ( I, %)( hkl)] are: 3.09(8)(12 overline 2 ); 2.84, 2.85(10)(021, 120); 2.64(8)(21 overline 3 ); 2.12(8)(31 overline 3 ); 1.785(8)(32 overline 4 ), 1.581(10)(24 overline 2 ); 1.432, 1.433(10)(322, 124). The chemical composition (electron microprobe, average of 237 point analyses

  1. Marine Mineral Exploration

    DEFF Research Database (Denmark)

    in EEZ areas are fairly unknown; many areas need detailed mapping and mineral exploration, and the majority of coastal or island states with large EEZ areas have little experience in exploration for marine hard minerals. This book describes the systematic steps in marine mineral exploration....... Such exploration requires knowledge of mineral deposits and models of their formation, of geophysical and geochemical exploration methods, and of data evaluation and interpretation methods. These topics are described in detail by an international group of authors. A short description is also given of marine...

  2. Optimization of seed germination in an Iranian serpentine endemic, Fortuynia garcinii

    NARCIS (Netherlands)

    Salehi Eskandari, Behrooz; Ghaderian, Seyed Majid; Ghasemi, Rasoul; Schat, Henk

    2017-01-01

    Fortuynia garcinii (Brassicaceae) is endemic to serpentine soils in central Iran. It has indehiscent silicles. The effects of its fruit pericarp on seed imbibition and germination were determined. The effects of moist chilling (15 days) and gibberellic acid (GA3, four levels), both alone and

  3. Physiological and genomic features of highly alkaliphilic hydrogen-utilizing Betaproteobacteria from a continental serpentinizing site

    NARCIS (Netherlands)

    Suzuki, S.; Kuenen, J.G.; Schipper, K.; van der Velde, S.; Ishii, S.; Wu, A.; Sorokin, D.Y.; Tenney, A.; Meng, X.Y.; Morrill, P.L.; Kamagata, Y.; Muyzer, G.; Nealson, K.H.

    2014-01-01

    Serpentinization, or the aqueous alteration of ultramafic rocks, results in challenging environments for life in continental sites due to the combination of extremely high pH, low salinity and lack of obvious electron acceptors and carbon sources. Nevertheless, certain Betaproteobacteria have been

  4. Microbial diversity in The Cedars, an ultrabasic, ultrareducing, and low salinity serpentinizing ecosystem.

    Science.gov (United States)

    Suzuki, Shino; Ishii, Shun'ichi; Wu, Angela; Cheung, Andrea; Tenney, Aaron; Wanger, Greg; Kuenen, J Gijs; Nealson, Kenneth H

    2013-09-17

    The Cedars, in coastal northern California, is an active site of peridotite serpentinization. The spring waters that emerge from this system feature very high pH, low redox potential, and low ionic concentrations, making it an exceptionally challenging environment for life. We report a multiyear, culture-independent geomicrobiological study of three springs at The Cedars that differ with respect to the nature of the groundwater feeding them. Within each spring, both geochemical properties and microbial diversity in all three domains of life remained stable over a 3-y period, with multiple samples each year. Between the three springs, however, the microbial communities showed considerable differences that were strongly correlated with the source of the serpentinizing groundwater. In the spring fed solely by deep groundwater, phylum Chloroflexi, class Clostridia, and candidate division OD1 were the major taxa with one phylotype in Euryarchaeota. Less-abundant phylotypes include several minor members from other candidate divisions and one phylotype that was an outlier of candidate division OP3. In the springs fed by the mixture of deep and shallow groundwater, organisms close to the Hydrogenophaga within Betaproteobacteria dominated and coexisted with the deep groundwater community members. The shallow groundwater community thus appears to be similar to those described in other terrestrial serpentinizing sites, whereas the deep community is distinctly different from any other previously described terrestrial serpentinizing community. These unique communities have the potential to yield important insights into the development and survival of life in these early-earth analog environments.

  5. A new modified-serpentine flow field for application in high temperature polymer electrolyte fuel cell

    DEFF Research Database (Denmark)

    Singdeo, Debanand; Dey, Tapobrata; Gaikwad, Shrihari

    2017-01-01

    field design is proposed and its usefulness for the fuel cell applications are evaluated in a high-temperature polymer electrolyte fuel cell. The proposed geometry retains some of the features of serpentine flow field such as multiple bends, while modifications are made in its in-plane flow path...

  6. Plants as extreme environments? Ni-resistant bacteria and Ni-hyperaccumulators of serpentine flora.

    NARCIS (Netherlands)

    Mengoni, A.; Schat, H.; Vangronsveld, J.

    2010-01-01

    During recent years there has been an increasing interest in the bacterial communities occurring in unusual, often extreme, environments. On serpentine outcrops around the world, a high diversity of plant species showing the peculiar features of metal hyperaccumulation is present. These metal

  7. The symbiosis with arbuscular mycorrhizal fungi contributes to plant tolerance to serpentine edaphic stress

    Czech Academy of Sciences Publication Activity Database

    Doubková, Pavla; Suda, Jan; Sudová, Radka

    2012-01-01

    Roč. 4, č. 1 (2012), s. 56-64 ISSN 0038-0717 R&D Projects: GA AV ČR KJB600050812 Institutional research plan: CEZ:AV0Z60050516 Keywords : serpentine syndrome * arbuscular mycorrhizal fungi * reciprocal transplant experiment Subject RIV: EF - Botanics Impact factor: 3.654, year: 2012

  8. Arbuscular mycorrhizal symbiosis alleviates drought stress imposed on Knautia arvensis plants in serpentine soil

    Czech Academy of Sciences Publication Activity Database

    Doubková, Pavla; Vlasáková, E.; Sudová, Radka

    2013-01-01

    Roč. 370, 1-2 (2013), s. 149-161 ISSN 0032-079X R&D Projects: GA AV ČR KJB600050812 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal fungi * drought * serpentine soil Subject RIV: EF - Botanics Impact factor: 3.235, year: 2013

  9. Methane Dynamics in a Tropical Serpentinizing Environment: The Santa Elena Ophiolite, Costa Rica

    Directory of Open Access Journals (Sweden)

    Melitza Crespo-Medina

    2017-05-01

    Full Text Available Uplifted ultramafic rocks represent an important vector for the transfer of carbon and reducing power from the deep subsurface into the biosphere and potentially support microbial life through serpentinization. This process has a strong influence upon the production of hydrogen and methane, which can be subsequently consumed by microbial communities. The Santa Elena Ophiolite (SEO on the northwestern Pacific coast of Costa Rica comprises ~250 km2 of ultramafic rocks and mafic associations. The climatic conditions, consisting of strongly contrasting wet and dry seasons, make the SEO a unique hydrogeological setting, where water-rock reactions are enhanced by large storm events (up to 200 mm in a single storm. Previous work on hyperalkaline spring fluids collected within the SEO has identified the presence of microorganisms potentially involved in hydrogen, methane, and methanol oxidation (such as Hydrogenophaga, Methylobacterium, and Methylibium spp., respectively, as well as the presence of methanogenic Archaea (such as Methanobacterium. Similar organisms have also been documented at other serpentinizing sites, however their functions have not been confirmed. SEO's hyperalkaline springs have elevated methane concentrations, ranging from 145 to 900 μM, in comparison to the background concentrations (<0.3 μM. The presence and potential activity of microorganisms involved in methane cycling in serpentinization-influenced fluids from different sites within the SEO were investigated using molecular, geochemical, and modeling approaches. These results were combined to elucidate the bioenergetically favorable methane production and/or oxidation reactions in this tropical serpentinizing environment. The hyperalkaline springs at SEO contain a greater proportion of Archaea and methanogens than has been detected in any terrestrial serpentinizing system. Archaea involved in methanogenesis and anaerobic methane oxidation accounted from 40 to 90% of total

  10. Laboratory simulations of prebiotic molecule stability in the jarosite mineral group; end member evaluation of detection and decomposition behavior related to Mars sample return

    Energy Technology Data Exchange (ETDEWEB)

    J. Michelle Kotler; Nancy W. Hinman; C. Doc Richardson; Andrew G. Conly; Jill R. Scott

    2009-10-01

    Recently, the prebiotic amino acid glycine has been found associated with natural jarosite samples from various locations around the world. Since the discovery of jarosite on Mars, extensive research focuses on linking this mineral group with possible detection of biosignatures in the geologic record on Earth and Mars. Multiple analytical methods, including extraction and mass spectrometry techniques have identified glycine and other biomolecules in jarosite samples. The jarosite end members jarosite (sensu stricto-potassium jarosite), natrojarosite (sodium jarosite), and ammoniojarosite (ammonium jarosite) have different thermodynamic stabilities, decompose at different rates, and have potentially different susceptibilities to substitution. Planetary protection issues have led to the suggestion that samples returned from Mars would need to be heat-treated before they could be analyzed on Earth. Although heat treatment of the samples would in theory destroy any potential biosignatures, valuable information can be obtained during thermal treatment by employing gravimetric techniques. The relationship between the thermodynamic stability of the jarosite end members and the effect that glycine has on the thermal decomposition behavior of each end member was investigated using thermal gravimetric analysis. Thermal gravimetric analysis has been suggested as a method capable of providing the heat treatment necessary to provide planetary protection while still providing useful information about the original state and composition of the potentially returned materials. Introducing glycine into the synthesis procedure of the potassium, sodium and ammonium jarosite end-member has elucidated the effects that glycine has on the thermal stability of the mineral group. Potassium jarosite appears to be the least susceptible to the effects of glycine, with the sodium and ammonium end members showing marked changes in thermal decomposition behavior and decomposition rates. In

  11. Miners' welfare

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, C

    1984-06-13

    The Miners' Welfare Committee (MWC) was formed in Britain in 1921 and initiated building programmes to provide welfare amenities for miners and families, using architecture to improve the quality of a miner's working and leisure time. The article reviews the MWC's work, and assesses the design and architecture at the Selby Coalfield. (7 refs.)

  12. Micro-structural and compositional variations of hydrothermal epidote-group minerals from a peralkaline granite, Corupá Pluton, Graciosa Province, South Brazil, and their petrological implications

    Directory of Open Access Journals (Sweden)

    Silvio R.F. Vlach

    2012-06-01

    Full Text Available Epidote-group minerals, together with albite, quartz, fluorite, Al-poor and Fe-rich phyllosilicates, zircon, and minor oxides and sulphides, are typical hydrothermal phases in peralkaline alkali-feldspar granites from the Corupá Pluton, Graciosa Province, South Brazil. The epidote-group minerals occur as single crystals and as aggregates filling in rock interstices and miarolitic cavities. They display complex recurrent zoning patterns with an internal zone of ferriallanite-(Ce, followed by allanite-(Ce, then epidote-ferriepidote, and an external zone with allanite-(Ce, with sharp limits, as shown in BSE and X-ray images. REE patterns show decreasing fractionation degrees of LREE over HREE from ferriallanite to epidote. The most external allanite is enriched in MREE. LA-ICP-MS data indicate that ferriallanite is enriched (>10-fold in Ti, Sr and Ga, and depleted in Mg, Rb, Th and Zr relative to the host granite. Allanite has lower Ga and Mn and higher Zr, Nb and U contents as compared to ferriallanite, while epidote is enriched in Sr, U and depleted in Pb, Zr, Hf, Ti and Ga. The formation of these minerals is related to the variable concentrations of HFSE, Ca, Al, Fe and F in fluids remaining from magmatic crystallization, in an oxidizing environment, close to the HM buffer. L-MREE were in part released by the alteration of chevkinite, their main primary repository in the host rocks.Minerais do grupo do epidoto, com albita, quartzo, fluorita, filossilicatos pobres em Al e ricos em Fe, zircão e quantidades menores de óxidos e sulfetos são fases hidrotermais típicas em álcali-feldpato granitos peralcalinos do Pluton Corupá, Província Graciosa, Sul do Brasil. Os minerais do grupo do epidoto ocorrem como cristais individuais ou agregados que preenchem interstícios e cavidades miarolíticas na rocha. Mostram zonamento complexo, recorrente, descrito por uma zona interna de ferriallanita-(Ce, seguida por allanita-(Ce, epidoto-ferriepidoto e uma

  13. Mineral potential for nickel, copper, platinum group elements(PGE), and chromium deposits hosted in ultramafic rocks in the Islamic Republic of Mauritania (phase V, deliverable 67): Chapter G in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)

    Science.gov (United States)

    Taylor, Cliff D.; Marsh, Erin; Anderson, Eric D.

    2015-01-01

    PRISM-I summary documents mention the presence of mafic-ultramafic igneous intrusive rocks in several areas of Mauritania and a number of chromium (Cr) and copper-nickel (Cu-Ni (±Co, Au)) occurrences associated with them. Permissive geologic settings generally include greenstone belts of any age, layered mafic-ultramafic and unlayered gabbro-anorthosite intrusive complexes in cratonic settings, ophiolite complexes, flood basalt provinces, and fluid-rich shear zones cutting accumulations of mafic-ultramafic rocks. Regions of Mauritania having these characteristics that are discussed in PRISM-I texts include the Mesoarchean greenstone belts of the TasiastTijirit terrane in the southwestern Rgueïbat Shield, two separate layered ultramafic complexes in the Amsaga Complex west of Atar, serpentinized metadunites in Mesoarchean rocks of the Rgueïbat Shield in the Zednes map sheet, several lateritized annular mafic-ultramafic complexes in the Paleoproterozoic northwestern portion of the Rgueïbat Shield, and the serpentinized ophiolitic segments of the Gorgol Noir Complex in the axial portion of the southern Mauritanides. Bureau de Recherches Géologiques et Minières (BRGM) work in the “Extreme Sud” zone also suggests that small copper occurrences associated with the extensive Jurassic microgabbroic intrusive rocks in the Taoudeni Basin of southeastern Mauritania could have potential for magmatic Cu-Ni (PGE, Co, Au) sulfide mineralization. Similarly, Jurassic mafic intrusive rocks in the northeastern Taoudeni Basin may be permissive. Known magmatic Cu-Ni deposits of these types in Mauritania are few in number and some uncertainty exists as to the nature of several of the more important ones.

  14. Methane-bearing fluids in subduction zones: an experimental study of abiotic methanogenesis during serpentinization at 12 kbar and 300°C

    Science.gov (United States)

    Lazar, C.; Manning, C. E.

    2009-12-01

    Serpentinization within subduction zones may generate reduced fluids that contain higher concentrations of abiotic methane than near-surface ultramafic environments. We present preliminary experimental data suggesting that the kinetics of abiotic methanogenesis are enhanced at high pressures. Thermodynamic calculations of C-O-H fluid speciations at the low oxygen fugacities attained during early serpentinization suggest complete conversion of oxidized carbon to methane, yet previous field and experimental investigations have reported fluid compositions with CH4/CO2 far below equilibrium (McCollom and Seewald, 2007). Much experimental work, therefore, has focused on CH4 production rates and the kinetic effects of temperature and mineral catalysis (Horita and Berdt, 1999; Foustoukos and Seyfried, 2004). Methane has been shown experimentally to form at very high pressures (Scott et al, 2004), but the quantitative effect of pressure on methanogenesis kinetics is unknown. We present preliminary results of a comparison of methane production rates at 0.35 and 12 kbar, 300°C, using experiments performed in piston cylinder and cold seal hydrothermal apparatus. Carbon was introduced as a roughly 70 mmol solution of isotopically-labeled formic acid, H13COOH, known to decompose to 13CO2 and H2 at run conditions. Roughly 15 mL of this solution, along with 1.9 mg of natural awaruite (Ni3Fe), was loaded into a gold capsule and then sealed via DC spot welding. Awaruite, a known methane catalyst (Horita and Berndt, 1999), was added to increase the overall rates of all experiments in order to boost the concentration for analysis and as an fO2 buffer appropriate for serpentinization. The experiments were held at T and P for approximately 160 hours. After each run, the capsule was placed in a gas vial and punctured with a needle. The contents of the vial were extracted via gas syringe and injected into gas chromatograph mass spectrometer (GC-MS). CH4 concentration in the 12 kbar run

  15. Modeling Late-State Serpentinization on Enceladus and Implications for Methane-Utilizing Microbial Metabolisms

    Science.gov (United States)

    Hart, R.; Cardace, D.

    2017-12-01

    Modeling investigations of Enceladus and other icy-satellites have included physicochemical properties (Sohl et al., 2010; Glein et al., 2015; Neveu et al., 2015), geophysical prospects of serpentinization (Malamud and Prialnik, 2016; Vance et al., 2016), and aqueous geochemistry across different antifreeze fluid-rock scenarios (Neveu et al., 2017). To more effectively evaluate the habitability of Enceladus, in the context of recent observations (Waite et al., 2017), we model the potential bioenergetic pathways that would be thermodynamically favorable at the interface of hydrothermal water-rock reactions resulting from late stage serpentinization (>90% serpentinized), hypothesized on Enceladus. Building on previous geochemical model outputs of Enceladus (Neveu et al., 2017), and bioenergetic modeling (as in Amend and Shock, 2001; Cardace et al., 2015), we present a model of late stage serpentinization possible at the water-rock interface of Enceladus, and report changing activities of chemical species related to methane utilization by microbes over the course of serpentinization using the Geochemist's Workbench REACT code [modified Extended Debye-Hückel (Helgeson, 1969) using the thermodynamic database of SUPCRT92 (Johnson et al., 1992)]. Using a model protolith speculated to exist at Enceladus's water-rock boundary, constrained by extraterrestrial analog analytical data for subsurface serpentinites of the Coast Range Ophiolite (Lower Lake, CA, USA) mélange rocks, we deduce evolving habitability conditions as the model protolith reacts with feasible, though hypothetical, planetary ocean chemistries (from Glien et al., 2015, and Neveu et al., 2017). Major components of modeled oceans, Na-Cl, Mg-Cl, and Ca-Cl, show shifts in the feasibility of CO2-CH4-H2 driven microbial habitability, occurring early in the reaction progress, with methanogenesis being bioenergetically favored. Methanotrophy was favored late in the reaction progress of some Na-Cl systems and in the

  16. A thermodynamic evaluation of the potential for cryptic formation of incidental Au-Fe alloy catalysts during flexible cell experimental studies of abiotic alkanogenesis during serpentinization

    Science.gov (United States)

    Lazar, C.

    2017-12-01

    The formation of abiotic alkanes via CO2 reduction during serpentinization is an important process in astrobiology and geochemistry. Aqueous alkane concentrations in natural settings are often non-equilibrated, thus motivating many experimental studies of CO2 reduction kinetics. A well-established result of such studies is the strong catalytic effect of metallic Feo on the conversion rate of CO2 to alkanes. Because alkanogenetic serpentinization experiments often feature Fe-bearing minerals contained in gold vessels, incidental metallic Feo may precipitate during an experiment as Au-Fe alloy. Such alloy may be catalytic, potentially leading to artificially rapid alkanogenesis and an overestimation of the catalytic strength of nominally nonmetallic Fe-bearing minerals, even if isotopically labeled 13C is used. To evaluate this potential for Au-Fe alloying, a thermodynamic analysis of the effect of oxygen fugacity on Au-Fe mixing has been performed at metamorphic grades relevant to experimental alkanogenesis. The results show that even relatively oxidized metal-free mineral assemblages such as the quartz-fayalite-magnetite buffer (QFM) can stably coexist with an Au-Fe alloy containing a few hundred ppm Fe. Given the strong catalytic effect of metallic Fe, any hydrocarbons generated during a hypothetical experiment containing, for example, the QFM assemblage might be catalyzed by trace Fe in an Au-Fe alloy, not by a QFM mineral. The effect is stronger for assemblages more reducing than QFM, which are notably common in serpentinites. This is a source of experimental uncertainty in reusable flexible gold cell apparatus that cannot be assessed by traditional blank experiments, which only demonstrate the effectiveness of post-run acid-cleaning procedures. A more effective approach would be the chemical analysis of a small, recoverable gold chip embedded into the experimental materials. By assuming that the experimental materials interact identically with the Au chip and

  17. Evaluation of Southern Quebec asbestos residues for CO2 sequestration by mineral carbonation

    Energy Technology Data Exchange (ETDEWEB)

    Beaudoin, G.; Hebert, R.; Constantin, M. [Laval Univ., Quebec City, PQ (Canada); Bonin, G. [LAB Chrysotile Inc., Black Lake, PQ (Canada); Dipple, G. [British Columbia Univ., Vancouver, BC (Canada)

    2003-08-01

    One alternative to help reduce carbon dioxide (CO{sub 2}) levels in the atmosphere is to sequester CO{sub 2} by mineral carbonation using ultramafic rock-hosted magnesian silicates (serpentine, olivine, talc). The carbonation process produces magnesite, which is a geologically stable and an environmentally safe magnesium carbonate. Three CO{sub 2} sinks exist in southern Quebec use such silicates. They are: (1) asbestos mill residues, (2) associated mine waste, and (3) ultramafic bedrock. Extraction of asbestos in the region has been accomplished from serpentinized harzburgite located in the Thetford Mines and Asbestos ophiolitic massifs and also from the highly sheared Pennington Sheet. The physical and chemical properties of magnesium silicate deposits greatly determine their carbonation potential. A wide range of properties was observed in samples obtained from almost all asbestos mill residues and waste. The reaction which takes place depends on the mineral content. The kinetics of the reactions are influenced by humidity and grain size.

  18. Depressing effect of phenoxyl acetic acids on flotation of minerals containing Ca2+/Mg2+ gangues

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Phenoxyl acetic acids were applied to determine their depressing effect on minerals containing Ca2+/Mg2+ gangues. Calcite,mixture of calcite and fluorite, and nickel ore were used in the flotation. And the depression mechanism was studied by the determination of contact angle, zeta potential, adsorptive capacity of collector, and IR analysis as well. It is found that 0.1 mmol/L of phenoxyl acetic acid derived from pyrogallol or gallic acid exhibits strong depressing ability on calcite in almost zero yields at pH value of 9.8, and calcite can be depressed in the flotation of calcite/fluorite mixture for approximate 87% yield of fluorite. The flotation result of practical nickel ore containing serpentine indicates that these two depressants may also show better depression performance to serpentine than traditional depressants such as sodium fluosilicate and carboxylmethyl cellulose. Analysis for the depression mechanism reveals that there exists strong chemical interaction between the depressants and minerals.

  19. Integrating Steel Production with Mineral Carbon Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Klaus Lackner; Paul Doby; Tuncel Yegulalp; Samuel Krevor; Christopher Graves

    2008-05-01

    The objectives of the project were (i) to develop a combination iron oxide production and carbon sequestration plant that will use serpentine ores as the source of iron and the extraction tailings as the storage element for CO2 disposal, (ii) the identification of locations within the US where this process may be implemented and (iii) to create a standardized process to characterize the serpentine deposits in terms of carbon disposal capacity and iron and steel production capacity. The first objective was not accomplished. The research failed to identify a technique to accelerate direct aqueous mineral carbonation, the limiting step in the integration of steel production and carbon sequestration. Objective (ii) was accomplished. It was found that the sequestration potential of the ultramafic resource surfaces in the US and Puerto Rico is approximately 4,647 Gt of CO2 or over 500 years of current US production of CO2. Lastly, a computer model was developed to investigate the impact of various system parameters (recoveries and efficiencies and capacities of different system components) and serpentinite quality as well as incorporation of CO2 from sources outside the steel industry.

  20. Growth Oscillatory Zoning in Erythrite, Ideally Co3(AsO4)2·8H2O: Structural Variations in Vivianite-Group Minerals

    Energy Technology Data Exchange (ETDEWEB)

    Antao, Sytle M.; Dhaliwal, Inayat

    2017-08-01

    The crystal structure of an oscillatory zoned erythrite sample from Aghbar mine, Bou Azzer, Morocco, was refined using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data, Rietveld refinement, space group C2/m, and Z = 2. The crystal contains two sets of oscillatory zones that appear to have developed during epitaxial growth. The unit-cell parameters obtained are a = 10.24799(3) Å, b = 13.42490(7) Å, c = 4.755885(8) Å, β = 105.1116(3)°, and V = 631.680(4) Å3. The empirical formula for erythrite, obtained with electron-probe micro-analysis (EPMA), is [Co2.78Zn0.11Ni0.07Fe0.04]Σ3.00(AsO4)2·8H2O. Erythrite belongs to the vivianite-type structure that contains M1O2(H2O)4 octahedra and M22O6(H2O)4 octahedral dimers that are linked by TO4 (T5+ = As or P) tetrahedra to form complex layers parallel to the (010) plane. These layers are connected by hydrogen bonds. The average [6] = 2.122(1) Å and average [6] = 2.088(1) Å. With space group C2/m, there are two solid solutions: M3(AsO4)2·8H2O and M3(PO4)2·8H2O where M2+ = Mg, Fe, Co, Ni, or Zn. In these As- and P-series, using data from this study and from the literature, we find that their structural parameters evolve linearly with V and in a nearly parallel manner despite of the large difference in size between P5+ (0.170 Å) and As5+ (0.355 Å) cations. Average [4], [6], and [6] distances increase linearly with V. The average distance is affected by M atoms, whereas the average distance is unaffected because it contains shorter and stronger P–O bonds. Although As- and P-series occur naturally, there is no structural reason why similar V-series vivianite-group minerals do not occur naturally or cannot be synthesized.

  1. Luminescence and paramagnetic centers in antigorite and Lizardite, two members of serpentine group: a comparative study

    International Nuclear Information System (INIS)

    Rocca, Rene Rojas

    2008-01-01

    In this work, we are describing crystals luminescent properties of Antigorite (monoclinic, Mg 3-x [Si 2 O 5 ](OH) 4-2x ) and Lizardite (triclinic, Mg 3 [(Si,Fe) 2 O 5 ](OH) 4 ). They were studied simultaneously applying several techniques, like: Thermoluminescence (TL), Optical Absorption (OA), Electron Paramagnetic Resonance (EPR), X-rays diffraction and Inductively Coupled Plasma (ICP). Using cold pressed elements and heating the samples to 350 deg C for TL measurements, we can observe reproductive peaks. Antigorita show well differentiated peaks and intensities, but Lizardite show overlapped and similar intensity peaks. Peaks of both samples occur around 150, 200, 250, 300 deg C, and all them grow linearly up to 2 kGy, saturating for high doses, except 250 deg C peak which continue growing with dose until 172 kGy. TL peaks trap parameters and lifetimes were calculated, the curves were fitted using the GCD method with second order kinetic. The EPR spectrum shows 6 hyperfine structure lines, characteristic of Manganese, besides lines due to Iron. It was possible also to observe two super hyperfine Mn 2+ lines. The EPR signal does not change with irradiation dose in both crystals. These impurities were also detected in the ICP analysis. The OA spectrum of lizardite show bands from 370 to 470 nm which were not observed in antigorite samples probably related to Fe 3+ and Mn 2+ . In the infrared region several (OA) bands of Mg-OH combination were observed. Again the OA spectrum of these crystals does not change with irradiation dose. We conclude that TL samples peaks around 150, 200, 250, 300 deg C can be used for radiation ionizing dosimetry (y-rays and B- particle) for intermediate and high doses. (author)

  2. Thermal, epithermal and thermalized neutron attenuation properties of ilmenite-serpentine heat resistant concrete shield

    International Nuclear Information System (INIS)

    Kany, A.M.I.; El-Gohary, M.I.; Kamal, S.M.

    1994-01-01

    Experimental measurements were carried out to study the attenuation properties of low-energy neutrons transmitted through unheated and preheated barriers of heavy-weight, highly hydrated and heat-resistant concrete shields. The concrete shields under investigation have been prepared from naturally occurring ilmenite and serpentine Egyptian ores. A collimated beam obtained from an Am-Be source was used as a source of neutrons, while the measurements of total thermal, epithermal, and thermalized neutron fluxes were performed using a BF-3 detector, multichannel analyzer and Cd filter. Results show that the ilmenite-serpentine concrete proved to be a better thermal, epithermal and thermalized neutron attenuator than the ordinary concrete especially at a high temperature of concrete exposure. (Author)

  3. Continuous particle separation in a serpentine microchannel via negative and positive dielectrophoretic focusing

    International Nuclear Information System (INIS)

    Church, Christopher; Zhu, Junjie; Nieto, Juan; Keten, Gyunay; Ibarra, Erl; Xuan, Xiangchun

    2010-01-01

    Dielectrophoresis (DEP) has been widely used to focus and separate cells and particles in microfluidic devices. This work first demonstrates negative and positive dielectrophoretic focusing of particles in a serpentine microchannel by changing only the electric conductivity of the suspending fluid. Due to the channel turn-induced dielectrophoretic force, particles are focused to either the centerline or the sidewalls of the channel when their electric conductivity is lower (i.e. negative DEP) or higher (i.e. positive DEP) than that of the fluid. These distinctive dielectrophoretic focusing phenomena in a serpentine microchannel are then combined to implement a continuous separation between particles of different sizes and electric conductivities. Such separation eliminates the fabrication of in-channel microelectrodes or micro-insulators that are typically required in DEP-based separation techniques. A numerical model is also developed to predict the particle motion, and the simulation results agree reasonably with the observed particle focusing and separation behaviors.

  4. A three-dimensional model of PEM fuel cells with serpentine flow channels

    International Nuclear Information System (INIS)

    Nguyen, P.T.; Berning, T.; Bang, M.; Djilali, N.

    2003-01-01

    A three-dimensional computational model of PEM fuel cell with serpentine flow field channels is presented in this paper. This model presents a comprehensive account for all important transport phenomena in fuel cell such as heat transfer, mass transfer, electrode kinetics, and potential fields in the membrane and gas diffusion layers. A new approach of solving for the potential losses across the cell was also developed in this model. The dependency of local current density on oxygen concentration and activation overpotential is fully addressed in this model. The computational domain consists of serpentine gas flow channels, porous gas diffusion layers, catalyst layers, and a membrane. Results obtained from this model are in good agreement with experimental results. (author)

  5. Malenco Serpentine: proposed as a candidate for "Global Heritage Stone Resource" designation

    Science.gov (United States)

    Primavori, Piero

    2017-04-01

    The Malenco Serpentine (Serpentine of Val Malenco) is the commercial name of a meta-peridotitic geological formation, Jurassic-Lower Cretaceous in age, entirely restricted to the borders of the valley of the same name (Malenco Valley), and geographically located in Sondrio Province, Lombardy Region, North Italy. Geologically speaking, it is part of an ophiolithic suture zone situated at the contact of the Austroalpine and Penninic nappes of the Alps (Rhaetian sector); petrographically, it is the result of a polymetamorphic (both regional and contact) and polytectonic history, with the development of a paragenesis of antigorite + chrysotile + chlorite + magnetite + diopside + olivine + titanolivine ± chromite ± pyrite ± brucite, and other iron and copper sulphurs. Malenco Serpentine extends over an area of approximately 170 km2, with a thickness ranging from 1 to 2 km. Lithological and mineralogical features allow the recognition of three distinct lythotypes: 1) a strongly foliated Serpentine - called Serpentine-schist of Val Malenco, with a regular and penetrative schistosity, which makes it possible to split the rock into very fine sheets ("pioda"); 2) a massive Serpentine, with no remarkable foliation, called with different commercial names (Green Vittoria, Green Mare, Green Torre S. Maria etc.); 3) A Clorithic schist (Val Malenco Ollare Stone), in turn subdivisible into two main types, depending on the predominance of Chlorite or Talc, and well known for their thermal behaviour and historical utilization for the production of stoves and cooking pots. The stone is quarried and processed since Middle Ages, and used in building and urban décor since 1800. Particularly, the splittable Serpentine has totally characterized - and still characterizes - the typology of the roofs and the urban style of the Malenco Valley architecture. "Pioda" is the name given to the roofing elements; initially used only for the local building, they were processed and transported out

  6. Serpentinization-Influenced Groundwater Harbors Extremely Low Diversity Microbial Communities Adapted to High pH.

    Science.gov (United States)

    Twing, Katrina I; Brazelton, William J; Kubo, Michael D Y; Hyer, Alex J; Cardace, Dawn; Hoehler, Tori M; McCollom, Tom M; Schrenk, Matthew O

    2017-01-01

    Serpentinization is a widespread geochemical process associated with aqueous alteration of ultramafic rocks that produces abundant reductants (H 2 and CH 4 ) for life to exploit, but also potentially challenging conditions, including high pH, limited availability of terminal electron acceptors, and low concentrations of inorganic carbon. As a consequence, past studies of serpentinites have reported low cellular abundances and limited microbial diversity. Establishment of the Coast Range Ophiolite Microbial Observatory (California, U.S.A.) allowed a comparison of microbial communities and physicochemical parameters directly within serpentinization-influenced subsurface aquifers. Samples collected from seven wells were subjected to a range of analyses, including solute and gas chemistry, microbial diversity by 16S rRNA gene sequencing, and metabolic potential by shotgun metagenomics, in an attempt to elucidate what factors drive microbial activities in serpentinite habitats. This study describes the first comprehensive interdisciplinary analysis of microbial communities in hyperalkaline groundwater directly accessed by boreholes into serpentinite rocks. Several environmental factors, including pH, methane, and carbon monoxide, were strongly associated with the predominant subsurface microbial communities. A single operational taxonomic unit (OTU) of Betaproteobacteria and a few OTUs of Clostridia were the almost exclusive inhabitants of fluids exhibiting the most serpentinized character. Metagenomes from these extreme samples contained abundant sequences encoding proteins associated with hydrogen metabolism, carbon monoxide oxidation, carbon fixation, and acetogenesis. Metabolic pathways encoded by Clostridia and Betaproteobacteria, in particular, are likely to play important roles in the ecosystems of serpentinizing groundwater. These data provide a basis for further biogeochemical studies of key processes in serpentinite subsurface environments.

  7. Early Thermal History of Rhea: The Role of Serpentinization and Liquid State Convection

    OpenAIRE

    Czechowski Leszek; Łosiak Anna

    2016-01-01

    Early thermal history of Rhea is investigated. The role of the following parameters of the model is investigated: time of beginning of accretion, tini, duration of accretion, tac, viscosity of ice close to the melting point, η0, activation energy in the formula for viscosity, E, thermal conductivity of silicate component, ksil, ammonia content, XNH3, and energy of serpentinization, cserp. We found that tini and tac are crucial for evolution. All other parameters are also important, but no dra...

  8. Characterizing Dissolved Organic Matter and Metabolites in an Actively Serpentinizing Ophiolite Using Global Metabolomics Techniques

    Science.gov (United States)

    Seyler, L. M.; Rempfert, K. R.; Kraus, E. A.; Spear, J. R.; Templeton, A. S.; Schrenk, M. O.

    2017-12-01

    Environmental metabolomics is an emerging approach used to study ecosystem properties. Through bioinformatic comparisons to metagenomic data sets, metabolomics can be used to study microbial adaptations and responses to varying environmental conditions. Since the techniques are highly parallel to organic geochemistry approaches, metabolomics can also provide insight into biogeochemical processes. These analyses are a reflection of metabolic potential and intersection with other organisms and environmental components. Here, we used an untargeted metabolomics approach to characterize dissolved organic carbon and aqueous metabolites from groundwater obtained from an actively serpentinizing habitat. Serpentinites are known to support microbial communities that feed off of the products of serpentinization (such as methane and H2 gas), while adapted to harsh environmental conditions such as high pH and low DIC availability. However, the biochemistry of microbial populations that inhabit these environments are understudied and are complicated by overlapping biotic and abiotic processes. The aim of this study was to identify potential sources of carbon in an environment that is depleted of soluble inorganic carbon, and to characterize the flow of metabolites and describe overlapping biogenic and abiogenic processes impacting carbon cycling in serpentinizing rocks. We applied untargeted metabolomics techniques to groundwater taken from a series of wells drilled into the Semail Ophiolite in Oman.. Samples were analyzed via quadrupole time-of-flight liquid chromatography tandem mass spectrometry (QToF-LC/MS/MS). Metabolomes and metagenomic data were imported into Progenesis QI software for statistical analysis and correlation, and metabolic networks constructed using the Genome-Linked Application for Metabolic Maps (GLAMM), a web interface tool. Further multivariate statistical analyses and quality control was performed using EZinfo. Pools of dissolved organic carbon could

  9. Design Methodology and Experimental Verification of Serpentine/Folded Waveguide TWTs

    Science.gov (United States)

    2016-03-17

    FW), oscillation, serpentine, stopband, traveling -wave tube (TWT), vacuum electronics. I. INTRODUCTION DEVELOPMENT of high-power broadband vacuum elec...tron devices (VEDs) beyond Ka-band using conventional coupled-cavity and helix traveling -wave tube (TWT) RF cir- cuit fabrication techniques is...bottom plot. III. G-BAND CIRCUIT DESIGN AND EXPERIMENTAL VALIDATION The primary motivation for the G-band amplifier was to develop a high-power broadband

  10. Technological project of serpentine raw material milling from Dobšiná heaps

    Directory of Open Access Journals (Sweden)

    Alena Pietriková

    2005-11-01

    Full Text Available Serpentine heaps in the surrounding of Dobšiná are an old ecological problem of the city and at the same time a suitable material for the production of MgCl2 and SiO2. The technology of the production is based on the chemical processing of the raw material, which is preceded by the raw material preparation comprising of the mechanical and hydraulic sorting, milling and the magnetic separation operations.

  11. An environmental survey of Serpentine Hot Springs: Geology, hydrology, geochemistry, and microbiology

    Science.gov (United States)

    Nordstrom, D. Kirk; Hasselbach, Linda; Ingebritsen, Steven E.; Skorupa, Dana; McCleskey, R. Blaine; McDermott, Timothy R.

    2015-01-01

    Serpentine Hot Springs is the most visited site in the Bering Land Bridge National Preserve. The hot springs have traditionally been used by the Native people of the Seward Peninsula for religious, medicinal and spiritual purposes and continue to be used in many of the same ways by Native people today. The hot springs are also popular with non-Native users from Nome and other communities, recreational users and pilots from out of the area, and hunters and hikers.

  12. Geogenic Enrichment of PTEs and the " Serpentine Syndrome"(H. Jenny, 1980). A proxy for soil remediation

    Science.gov (United States)

    Bini, Claudio; Maleci, Laura

    2014-05-01

    Serpentine soils have relatively high concentrations of PTEs (e.g., Co, Cr, Cu, Fe, Ni) but generally low amounts of major nutrients. They often bear a distinctive vegetation, and a frequently-used approach to understanding serpentine ecology and environmental hazard has been the chemical analysis of soils and plants. Long-term studies on aspects of serpentine soils and their vegetation provide results on total concentrations, or on plant-available fractions, of soil elements which counteract ecological conditions. For example, there is evidence of Ni toxicity at Ni-concentration >0.3 mg/L in the soil solution (Johnston and Proctor, 1981). The serpentine vegetation differs from the conterminous non-serpentine areas, being often endemic, and showing macroscopic physionomical characters such as dwarfism, prostrate outcome, glaucescence and glabrescence, leaves stenosis, root shortening (what Jenny, 1980, called "the serpentine syndrome"). Similarly, at microscopic level cytomorphological characteristics of the roots and variations in biochemical parameters such as LPO and phenols have been recorded in serpentine native vegetation (Giuliani et al., 2008). Light microscopy observations showed depressed mitotic activity in the meristematic zone, and consequent reduced root growth (Gabbrielli et al., 1990) The metal content of plants growing on serpentine soils at sites with different microclimatic conditions has been examined by several authors (e.g. Bini et al., 1993; Dinelli and Lombini, 1996) . A preferential Ni distribution in epidermis and sclerenchima has been observed in the stem of Alyssum bertoloni, a well known Ni-accumulator plant (Vergnano Gambi, 1975). The different tolerance mechanisms responsible for plant adaption to high concentrations of PTEs in serpentine soils can be related to the capacity of plants either to limit metal uptake and translocation or to accumulate metals in non toxic forms. The majority of serpentine species (e.g. Silene italica) tend

  13. The H2/CH4 ratio during serpentinization cannot reliably identify biological signatures.

    Science.gov (United States)

    Huang, Ruifang; Sun, Weidong; Liu, Jinzhong; Ding, Xing; Peng, Shaobang; Zhan, Wenhuan

    2016-09-26

    Serpentinization potentially contributes to the origin and evolution of life during early history of the Earth. Serpentinization produces molecular hydrogen (H 2 ) that can be utilized by microorganisms to gain metabolic energy. Methane can be formed through reactions between molecular hydrogen and oxidized carbon (e.g., carbon dioxide) or through biotic processes. A simple criterion, the H 2 /CH 4 ratio, has been proposed to differentiate abiotic from biotic methane, with values approximately larger than 40 for abiotic methane and values of serpentinization experiments at 200 °C and 0.3 kbar. However, it is not clear whether the criterion is applicable at a wider range of temperatures. In this study, we performed sixteen experiments at 311-500 °C and 3.0 kbar using natural ground peridotite. Our results demonstrate that the H 2 /CH 4 ratios strongly depend on temperature. At 311 °C and 3.0 kbar, the H 2 /CH 4 ratios ranged from 58 to 2,120, much greater than the critical value of 40. By contrast, at 400-500 °C, the H 2 /CH 4 ratios were much lower, ranging from 0.1 to 8.2. The results of this study suggest that the H 2 /CH 4 ratios cannot reliably discriminate abiotic from biotic methane.

  14. Three-dimensional flow measurements induced from serpentine plasma actuators in quiescent air

    International Nuclear Information System (INIS)

    Durscher, R J; Roy, S

    2012-01-01

    This paper presents three-dimensional flow measurements performed on a dielectric barrier discharge (DBD) actuator with the electrodes in a serpentine design. Such a configuration induces a local pinching and a local spreading of the fluid as one follows along the span of the actuator. In this work two different variations on the serpentine configuration are evaluated: one constructed from patterned circular arcs and one from patterned rectangles. The influence of applied voltage is studied for the former case. To quantify these effects stereo particle image velocimetry (PIV) is used to generate time averaged, spatially resolved measurements of the detailed flow structure. The three components of the velocity vector are measured along spanwise and streamwise cuts. These slices are then reconstructed to provide a three-dimensional view of the induced flow field. The results for the induced flow fields are also compared with stereo-PIV measurements made on a standard linear DBD actuator. A truly three-dimensional induced flow field was observed as a result of the serpentine configuration. These designs could be beneficial for rapid mixing of the local fluid. (paper)

  15. The H2/CH4 ratio during serpentinization cannot reliably identify biological signatures

    Science.gov (United States)

    Huang, Ruifang; Sun, Weidong; Liu, Jinzhong; Ding, Xing; Peng, Shaobang; Zhan, Wenhuan

    2016-09-01

    Serpentinization potentially contributes to the origin and evolution of life during early history of the Earth. Serpentinization produces molecular hydrogen (H2) that can be utilized by microorganisms to gain metabolic energy. Methane can be formed through reactions between molecular hydrogen and oxidized carbon (e.g., carbon dioxide) or through biotic processes. A simple criterion, the H2/CH4 ratio, has been proposed to differentiate abiotic from biotic methane, with values approximately larger than 40 for abiotic methane and values of serpentinization experiments at 200 °C and 0.3 kbar. However, it is not clear whether the criterion is applicable at a wider range of temperatures. In this study, we performed sixteen experiments at 311-500 °C and 3.0 kbar using natural ground peridotite. Our results demonstrate that the H2/CH4 ratios strongly depend on temperature. At 311 °C and 3.0 kbar, the H2/CH4 ratios ranged from 58 to 2,120, much greater than the critical value of 40. By contrast, at 400-500 °C, the H2/CH4 ratios were much lower, ranging from 0.1 to 8.2. The results of this study suggest that the H2/CH4 ratios cannot reliably discriminate abiotic from biotic methane.

  16. Stable and High Ajmalicine or Serpentine Production of Gamma Radiation Induction Mutant Catharantus Roseus

    International Nuclear Information System (INIS)

    Sumaryati Syukur

    2004-01-01

    Catharantus roseus Mutant have been selected by gamma irradiation with 20 krad doses of radiation and characterized as biochemical mutant with anti-feed back inhibition mechanism of tritophan decarboxylase (TDR) enzyme in biosynthetic path way of indole alkaloid. Production of indole alkaloid mainly ajmalicine with high economical values as a pharmaceutical drug for heart attack have been studied by using cell suspension cultures with several variation of medium, elicitors and stress osmosis. This treatment produced variation of indole alkaloid ajmalicine and serpentine. Several induction methods using Murashige and Skoog (MS) medium and polyethylene glycol PEG (6000) 1 to 7%, with hormones concentration of 2,4-D and kinetin as (10 : 1), showed optimal results of ajmalicine range between 20 and 50 nmol/gFW, and serpentine 10 to 60 nmol/gFW. This production increases ten time in mutant (20 Krad) by stress osmotic condition and performed long term stability in culture without subculture. In this paper explanation in detail about the selection methods, stability of mutant and the production of indole alkaloid ajmalicine and serpentine during growth phase, such as adaptation, log, and stationar in suspention culture of mutan cells. (author)

  17. Analysis of Passive Mixing in a Serpentine Microchannel with Sinusoidal Side Walls

    Directory of Open Access Journals (Sweden)

    Muhammad Usman Javaid

    2017-12-01

    Full Text Available Sample mixing is difficult in microfluidic devices because of laminar flow. Micromixers are designed to ensure the optimal use of miniaturized devices. The present study aims to design a chaotic-advection-based passive micromixer with enhanced mixing efficiency. A serpentine-shaped microchannel with sinusoidal side walls was designed, and three cases, with amplitude to wavelength (A/λ ratios of 0.1, 0.15, and 0.2 were investigated. Numerical simulations were conducted using the Navier–Stokes equations, to determine the flow field. The flow was then coupled with the convection–diffusion equation to obtain the species concentration distribution. The mixing performance of sinusoidal walled channels was compared with that of a simple serpentine channel for Reynolds numbers ranging from 0.1 to 50. Secondary flows were observed at high Reynolds numbers that mixed the fluid streams. These flows were dominant in the proposed sinusoidal walled channels, thereby showing better mixing performance than the simple serpentine channel at similar or less mixing cost. Higher mixing efficiency was obtained by increasing the A/λ ratio.

  18. Combined endophytic inoculants enhance nickel phytoextraction from serpentine soil in the hyperaccumulator Noccaea caerulescens.

    Science.gov (United States)

    Visioli, Giovanna; Vamerali, Teofilo; Mattarozzi, Monica; Dramis, Lucia; Sanangelantoni, Anna M

    2015-01-01

    This study assesses the effects of specific bacterial endophytes on the phytoextraction capacity of the Ni-hyperaccumulator Noccaea caerulescens, spontaneously growing in a serpentine soil environment. Five metal-tolerant endophytes had already been selected for their high Ni tolerance (6 mM) and plant growth promoting ability. Here we demonstrate that individual bacterial inoculation is ineffective in enhancing Ni translocation and growth of N. caerulescens in serpentine soil, except for specific strains Ncr-1 and Ncr-8, belonging to the Arthrobacter and Microbacterium genera, which showed the highest indole acetic acid production and 1-aminocyclopropane-1-carboxylic acid-deaminase activity. Ncr-1 and Ncr-8 co-inoculation was even more efficient in promoting plant growth, soil Ni removal, and translocation of Ni, together with that of Fe, Co, and Cu. Bacteria of both strains densely colonized the root surfaces and intercellular spaces of leaf epidermal tissue. These two bacterial strains also turned out to stimulate root length, shoot biomass, and Ni uptake in Arabidopsis thaliana grown in MS agar medium supplemented with Ni. It is concluded that adaptation of N. caerulescens in highly Ni-contaminated serpentine soil can be enhanced by an integrated community of bacterial endophytes rather than by single strains; of the former, Arthrobacter and Microbacterium may be useful candidates for future phytoremediation trials in multiple metal-contaminated sites, with possible extension to non-hyperaccumulator plants.

  19. Combined endophytic inoculants enhance nickel phytoextraction from serpentine soil in the hyperaccumulator Noccaea caerulescens

    Directory of Open Access Journals (Sweden)

    Giovanna eVisioli

    2015-08-01

    Full Text Available This study assesses the effects of specific bacterial endophytes on the phytoextraction capacity of the Ni-hyperaccumulator Noccaea caerulescens, spontaneously growing in a serpentine soil environment. Five metal-tolerant endophytes had already been selected for their high Ni tolerance (6 mM and plant growth promoting ability. Here we demonstrate that individual bacterial inoculation is ineffective in enhancing Ni translocation and growth of N. caerulescens in serpentine soil, except for specific strains Ncr-1 and Ncr-8, belonging to the Arthrobacter and Microbacterium genera, which showed the highest IAA production and ACC-deaminase activity. Ncr-1 and Ncr-8 co-inoculation was even more efficient in promoting plant growth, soil Ni removal and translocation of Ni, together with that of Fe, Co and Cu. Bacteria of both strains densely colonised the root surfaces and intercellular spaces of leaf epidermal tissue. These two bacterial strains also turned out to stimulate root length, shoot biomass and Ni uptake in Arabidopsis thaliana grown in MS agar medium supplemented with Ni. It is concluded that adaptation of N. caerulescens in highly Ni-contaminated serpentine soil can be enhanced by an integrated community of bacterial endophytes rather than by single strains; of the former, Arthrobacter and Microbacterium may be useful candidates for future phytoremediation trials

  20. Continuing Studies on Direct Aqueous Mineral Carbonation of CO{sub 2} Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    O' Connor, W.K.; Dahlin, D.C.; Nilsen, D.N.; Gerdemann, S.J.; Rush, G.E.; Penner, L.R.; Walters, R.P.; Turner, P.C.

    2002-03-04

    Direct aqueous mineral carbonation has been investigated as a process to convert gaseous CO{sub 2} into a geologically stable, solid final form. The process utilizes a solution of sodium bicarbonate (NaHCO{sub 3}), sodium chloride (NaCl), and water, mixed with a mineral reactant, such as olivine (Mg{sub 2}SiO{sub 4}) or serpentine [Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}]. Carbon dioxide is dissolved into this slurry, by diffusion through the surface and gas dispersion within the aqueous phase. The process includes dissolution of the mineral and precipitation of the magnesium carbonate mineral magnesite (MgCO{sub 3}) in a single unit operation. Activation of the silicate minerals has been achieved by thermal and mechanical means, resulting in up to 80% stoichiometric conversion of the silicate to the carbonate within 30 minutes. Heat treatment of the serpentine, or attrition grinding of the olivine and/or serpentine, appear to activate the minerals by the generation of a non-crystalline phase. Successful conversion to the carbonate has been demonstrated at ambient temperature and relatively low (10 atm) partial pressure of CO{sub 2} (P{sub CO2}). However, optimum results have been achieved using the bicarbonate-bearing solution, and high P{sub CO2}. Specific conditions include: 185 C; P{sub CO2}=150 atm; 30% solids. Studies suggest that the mineral dissolution rate is not solely surface controlled, while the carbonate precipitation rate is primarily dependent on the bicarbonate concentration of the slurry. Current and future activities include further examination of the reaction pathways and pretreatment options, the development of a continuous flow reactor, and an evaluation of the economic feasibility of the process.

  1. [Pneumoconiosis in bauxite miners].

    Science.gov (United States)

    Molinini, R; Pesola, M; Digennaro, M A; Carino, M; Nuzzaco, A; Coviello, F

    1985-01-01

    The authors examined a group of 40 miners who were being working at an Apulian bauxite mine, presently inactive. Radiographic findings of pulmonary micronodulation without significant reduction of lung functions were showed in 15 miners. Mineralogical analysis of mine dust samples excluded any presence of more than 1% free silica. As a result of this study hypotheses have been formulated about pathogenesis of this moderated and non-invasive pneumoconiosis, showed in long exposed subjects to low silica content dusts.

  2. PIXE analysis of nephrite minerals from different deposits

    Science.gov (United States)

    Zhang, Z. W.; Gan, F. X.; Cheng, H. S.

    2011-02-01

    External-beam PIXE was used to determine the major, minor and trace elements of 45 nephrite minerals from 14 different deposits, including China and other countries. Depending on the R∗ value (mole percent of Mg 2+/(Mg 2+ + Fe 2+(3+))) and content of Cr, Co and Ni, two types of nephrite minerals from dolomite and serpentinized ultramafic deposits can be more accurately distinguished. Besides, the nephrite minerals from Xiaomeiling and Wenchuan deposit can be distinguished with others from dolomite deposits, through the content of Sr and Mn/Fe value, respectively. Moreover, depending on the Sr content, clear evidence was given to prove that the raw materials of ancient nephrite artifacts from Liangzhu culture ruins are not from Xiaomeiling nephrite deposit. Furthermore, PIXE as a non-destructive method will be more used to study ancient nephrite artifacts, so these results can provide scientific basis for seeking the provenance of nephrite raw materials.

  3. High Resolution Mineral Mapping of the Oman Drilling Project Cores with Imaging Spectroscopy: Preliminary Results

    Science.gov (United States)

    Greenberger, R. N.; Ehlmann, B. L.; Kelemen, P. B.; Manning, C. E.; Teagle, D. A. H.; Harris, M.; Michibayashi, K.; Takazawa, E.

    2017-12-01

    The Oman Drilling Project provides an unprecedented opportunity to study the formation and alteration of oceanic crust and peridotite. Key to answering the main questions of the project are a characterization of the primary and secondary minerals present within the drill core and their spatial relationships. To that end, we used the Caltech imaging spectrometer system to scan the entire 1.5-km archive half of the core from all four gabbro and listvenite boreholes (GT1A, GT2A, GT3A, and BT1B) at 250 µm/pixel aboard the JAMSTEC Drilling Vessel Chikyu during the ChikyuOman core description campaign. The instrument measures the visible and shortwave infrared reflectance spectra of the rocks as a function of wavelength from 0.4 to 2.6 µm. This wavelength range is sensitive to many mineral groups, including hydrated minerals (phyllosilicates, zeolites, amorphous silica polytypes), carbonates, sulfates, and transition metals, most commonly iron-bearing mineralogies. To complete the measurements, the core was illuminated with a halogen light source and moved below the spectrometer at 1 cm/s by the Chikyu's Geotek track. Data are corrected and processed to reflectance using measurements of dark current and a spectralon calibration panel. The data provide a unique view of the mineralogy at high spatial resolution. Analysis of the images for complete downhole trends is ongoing. Thus far, a variety of minerals have been identified within their petrologic contexts, including but not limited to magnesite, dolomite, calcite, quartz (through an Si-OH absorption due to minor H2O), serpentine, chlorite, epidote, zeolites, mica (fuchsite), kaolinite, prehnite, gypsum, amphibole, and iron oxides. Further analysis will likely identify more minerals. Results include rapidly distinguishing the cations present within carbonate minerals and identifying minerals of volumetrically-low abundance within the matrix and veins of core samples. This technique, for example, accurately identifies

  4. Serpentine tube heat transfer characteristic under accident condition in gas cooled reactors

    International Nuclear Information System (INIS)

    Abouhadra, D.S.; Byrne, J.E.

    2004-01-01

    In nuclear reactors of the Magnox or advanced gas Cooled type, serpentine tubing is used in some designs to generate steam in a once through arrangement. The calculation of accident conditions using two phase flow codes requires knowledge of the heat transfer behavior of the boiler steam side. A series of experiments to study the blowdown characteristics of a typical serpentine boiler section was devised in order to validate the MARTHA section of the MACE code used by nuclear Electric. The tests were carried out on the Thermal Hydraulics Experimental Research Assembly (THERA) loop at Manchester University. The Thermal Hydraulic Experimental Research Assembly was designed to operate with pressures up to 180 bar and temperatures of 450degC. The geometry and dimensions of this test section were similar to part of a gas cooled reactor boiler of the Hinkley Point design. Blowdown from a pressure of 60 bar with subcoolings of 5degC, 50degC, 100degC formed the main part of the programme. A set of tests was conducted using discharge orifices of different sizes to produce depressurization times from 30 s to 10 mins, and in a few cases, the duration of blowdown approached 1 hour. These times were defined using the criterion of blowdown end as a final pressure of 10% of the initial pressure. Pressures, wall and fluid temperatures were all measured at average time intervals of 1.1s during the excursion and an inventory of the remaining water content in the serpentine was taken when the blowdown ended. Some tests were also conducted at an initial pressure of 30 bar. The results obtained show interesting stratification effects for the relatively fast discharge, with substantial wall circumferential temperature variations. For these tests, a relatively small water inventory remained after blowdown. The discharge characteristics of the serpentine in terms of orifice size have been mapped, and tests at 30 bar show the equivalence in terms of orifice size have been mapped

  5. A method for permanent CO2 mineral carbonation

    Energy Technology Data Exchange (ETDEWEB)

    Dahlin, David C.; O' Connor, William K.; Nilsen, David N.; Rush, G.E.; Walters, Richard P.; Turner, Paul C.

    2000-01-01

    The Albany Research Center (ARC) of the U.S. Department of Energy (DOE) has been conducting research to investigate the feasibility of mineral carbonation as a method for carbon dioxide (CO2) sequestration. The research is part of a Mineral Carbonation Study Program within the Office of Fossil Energy in DOE. Other participants in this Program include DOE?s Los Alamos National Laboratory and National Energy Technology Laboratory, Arizona State University, and Science Applications International Corporation. The research has focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC reacts a slurry of magnesium silicate mineral with supercritical CO2 to produce a solid magnesium carbonate product. To date, olivine and serpentine have been used as the mineral reactant, but other magnesium silicates could be used as well. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and consequently, these results may also be applicable to strategies for in-situ geological sequestration. Baseline tests were begun in distilled water on ground products of foundry-grade olivine. Tests conducted at 150 C and subcritical CO2 pressures (50 atm) resulted in very slow conversion to carbonate. Increasing the partial pressure of CO2 to supercritical (>73 atm) conditions, coupled with agitation of the slurry and gas dispersion within the water column, resulted in significant improvement in the extent of reaction in much shorter reaction times. A change from distilled water to a bicarbonate/salt solution further improved the rate and extent of reaction. When serpentine, a hydrated mineral, was used instead of olivine, extent of reaction was poor until heat treatment was included prior to the carbonation reaction. Removal of the chemically bound water resulted in conversion to carbonate similar to those obtained with olivine. Recent results have shown that conversions of nearly 80 pct are achievable after 30 minutes

  6. Isotope analysis of closely adjacent minerals

    International Nuclear Information System (INIS)

    Smith, M.P.

    1990-01-01

    This patent describes a method of determining an indicator of at least one of hydrocarbon formation, migration, and accumulation during mineral development. It comprises: searching for a class of minerals in a mineral specimen comprising more than one class of minerals; identifying in the mineral specimen a target sample of the thus searched for class; directing thermally pyrolyzing laser beam radiation onto surface mineral substance of the target sample in the mineral specimen releasing surface mineral substance pyrolysate gases therefrom; and determining isotope composition essentially of the surface mineral substance from analyzing the pyrolysate gases released from the thus pyrolyzed target sample, the isotope composition including isotope(s) selected from the group consisting of carbon, hydrogen, and oxygen isotopes; determining an indicator of at least one of hydrocarbon formation, migration, and accumulation during mineral development of the target mineral from thus determined isotope composition of surface mineral substance pyrolysate

  7. Calciopetersite from Domašov nad Bystřicí, Northen Moravia (Czech Republic), a new mineral species of the mixite group

    Czech Academy of Sciences Publication Activity Database

    Sejkora, J.; Novotný, P.; Novák, M.; Šrein, Vladimír; Berlepsch, P.

    2005-01-01

    Roč. 43, č. 4 (2005), 1393-1400 ISSN 0008-4476 Institutional research plan: CEZ:AV0Z30460519 Keywords : calciopetersite * new mineral species * X-ray poder diffraction Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.259, year: 2005

  8. Development of a food group-based diet score and its association with bone mineral density in the elderly: the Rotterdam Study

    NARCIS (Netherlands)

    Jonge, de E.A.L.; Kiefte-de Jong, J.C.; Groot, de C.P.G.M.; Voortman, T.; Schoufour, J.D.; Zillikens, M.C.; Hofman, A.; Uitterlinden, A.G.; Franco, O.H.; Rivadeneira, F.

    2015-01-01

    No diet score exists that summarizes the features of a diet that is optimal for bone mineral density (BMD) in the elderly. Our aims were (a) to develop a BMD-Diet Score reflecting a diet that may be beneficial for BMD based on the existing literature, and (b) to examine the association of the

  9. Comparison of three mineral candidates in middle and low-pressure condition. Experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Heng; Zhang, Jun-ying; Zhao, Yong-chun; Wang, Zhi-lang; Pan, Xia; Xu, Jun; Zheng, Chu-guang [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion

    2013-07-01

    ''Greenhouse Effect'', which is scientifically proven to be main caused by the increasing concentration of CO{sub 2}, has become a topic of national and international concern. Mineral carbonation, such as carbonation of alkaline silicate Ca/Mg minerals, analogous to natural weathering processes, is a potentially attractive route to mitigate possible global warming on the basis of industrial imitation of natural weathering processes. In this paper, three typical natural mineral candidates in China, serpentine, olivine and wollastonite, were selected as carbonation raw materials for direct mineral carbonation experiments under middle and low-pressure. A series number of experiments were carried out to investigate the factors that influence the conversion of carbonation reaction, such as reaction temperature, reaction pressure, particle size, solution composition and pretreatment. The solid products from carbonation experiments were filtered, collected, dried and analyzed by X-ray diffraction (XRD) and field scanning electron microscopy equipped with energy dispersive X-ray analysis (FSEM-EDX) to identify the reaction of mineral carbonation. And the method of mass equilibrium after heat decomposition was used to calculate the mineral carbonation conversion. All the XRD and FSEM analysis validate that carbonation reaction was occurred during the experiments and mineral carbonation is one of the potential techniques for carbon dioxide sequestration. The data of mass equilibrium after heat decomposition was collected and then the conversion formula was used to calculate the carbonation conversion of all the three mineral candidates. The mass equilibrium results show that, for all of the three mineral materials, the carbonation conversion increases with the increasing of reaction temperature. But once the temperature increases above 150 C, the conversion of serpentine decreases a little. Reaction pressure is also an important factor to mineral

  10. Lower Crustal Strength Controls on Melting and Serpentinization at Magma-Poor Margins: Potential Implications for the South Atlantic

    Science.gov (United States)

    Ros, Elena; Pérez-Gussinyé, Marta; Araújo, Mario; Thoaldo Romeiro, Marco; Andrés-Martínez, Miguel; Morgan, Jason P.

    2017-12-01

    Rifted continental margins may present a predominantly magmatic continent-ocean transition (COT), or one characterized by large exposures of serpentinized mantle. In this study we use numerical modeling to show the importance of the lower crustal strength in controlling the amount and onset of melting and serpentinization during rifting. We propose that the relative timing between both events controls the nature of the COT. Numerical experiments for half-extension velocities serpentinized mantle underlain by some magmatic products. In contrast, a weak lower crust promotes margins with a gentle crustal tapering, small faults dipping both ocean- and landward and small syn-rift subsidence. Their COT is predominantly magmatic at any ultra-slow extension velocity and perhaps underlain by some serpentinized mantle. These margins can also be either symmetric or asymmetric. Our models predict that magmatic underplating mostly underlies the wide margin at weak asymmetric conjugates, whereas the wide margin is mainly underlain by serpentinized mantle at strong asymmetric margins. Based on this conceptual template, we propose different natures for the COTs in the South Atlantic.

  11. Weak Serpentine-bearing Fault Zones: laboratory evidence and implications for the activity of of oceanic detachments

    Science.gov (United States)

    Tesei, T.; Harbord, C. W. A.; Paola, N.; Collettini, C.; Viti, C.

    2017-12-01

    Serpentinites are major constituents of oceanic lithosphere shear zones located at slow-spreading margins, transform plate boundaries and obduction complexes. Geological and geophysical evidence suggests that these shear zones are inherently weak and, therefore, studies of serpentine friction are of paramount importance to constrain the strength of oceanic faults. However, laboratory friction experiments give a wide range of friction values for serpentine, which are not conclusive to explain the observed fault weakness. These variable results may arise from the difficulties to accurately characterize the mineralogical composition of serpentinite rocks and, hence, from the lack of pure monomineralic reference samples. Here we present laboratory experiments performed on a suite of serpentine samples, whose mineralogical composition was accurately characterized from the hand specimen down to the nanoscale. We observe that the main, low temperature polymorphs components of ocean-floor retrograde serpentinites (e.g. lizardite, chrysotile and polygonal serpentine) exhibit friction coefficients, µ reported, over a range of pressure and temperature conditions. We applied the frictional reactivation theory based on our experimental result to serpentine-bearing oceanic detachments. We show that detachments may slip until they rotate to very shallow dips 15°, as documented along some Atlantic detachments, accommodating large amounts of extension before being abandoned.

  12. Aggregate and Mineral Resources - Minerals

    Data.gov (United States)

    NSGIC State | GIS Inventory — This point occurrence data set represents the current mineral and selected energy resources of Utah. The data set coordinates were derived from USGS topographic maps...

  13. CO{sub 2} emissions: mineral carbonation and Finnish pulp and paper industry (CO{sub Nordic Plus}) and use of serpentinites in energy and metal industry (ECOSERP); Hiilidioksidipaeaestoet: Mineraalikarbonointi ja Suomen massaja paperiteollisuus (CO{sub 2} Nordic plus) ja serpentiinin hyoetykaeyttoe energia- ja metalliteollisuudessa (ECOSERP)

    Energy Technology Data Exchange (ETDEWEB)

    Fogelholm, C.J.; Raiski, T.; Teir, S. [Helsinki Univ. of Technology, Espoo (Finland). Lab of Energy Engineering and Environmental Protection

    2006-12-19

    Mineral carbonation has been investigated at Helsinki University of Technology (TKK), laboratory of energy engineering and environmental protection since year 2000. The Finnish Technology Agency Tekes and the Finnish Recovery Boiler Committee are funding through the ClimBus technology programme, in conjunction with the Nordic Energy Research Programme, the research regarding the application of ex situ mineral carbonation processes. One aspect is to verify the possible use of mineral carbonation for the separation, utilisation and long-term storage of carbon dioxide (CO2) in the pulp and paper industry. The Geological Survey of Finland (GTK) has been screening since 2004 the location, quality and suitability of the Finnish processed serpentine and stopped serpentinite storage of mines and in situ serpentinite bodies of ultramafic rock formations for mineral carbonation of CO2. Tekes and the GTK are funding development work through the ClimBus technology programme on the utilisation of serpentine and serpentinite for CO2 sequestration purposes, based on economical and environmental evaluation of mineral and mining processing operations. Also the options for other use of serpentine and serpentinite are evaluated. The most promising magnesium and calcium-based sources for carbonation are by products of mining processes of ultramafic rocks (such as serpentinites and serpentine) and steelmaking slags. Carbonated minerals could possibly be used as paper coating materials (PCC), fillers or construction materials. For magnesium carbonate new markets and applications must be developed. (orig.)

  14. Serpentine endophytic bacterium Pseudomonas azotoformans ASS1 accelerates phytoremediation of soil metals under drought stress.

    Science.gov (United States)

    Ma, Ying; Rajkumar, Mani; Moreno, António; Zhang, Chang; Freitas, Helena

    2017-10-01

    This study evaluates the potential of serpentine endophytic bacterium to foster phytoremediation efficiency of Trifolium arvense grown on multi-metal (Cu, Zn and Ni) contaminated soils under drought stress. A drought resistant endophytic bacterial strain ASS1 isolated from the leaves of Alyssum serpyllifolium grown in serpentine soils was identified as Pseudomonas azotoformans based on biochemical tests and partial 16S rRNA gene sequencing. P. azotoformans ASS1 possessed abiotic stress resistance (heavy metals, drought, salinity, antibiotics and extreme temperature) and plant growth promoting (PGP) properties (phosphate solubilization, nitrogen fixation, production of 1-aminocyclopropane-1-carboxylate deaminase, siderophore and ammonia). Inoculation of T. arvense with ASS1 considerably increased the plant biomass and leaf relative water content in both roll towel assay and pot experiments in the absence and presence of drought stress (DS). In the pot experiments, ASS1 greatly enhanced chlorophyll content, catalase, peroxidase, superoxide dismutase activities, and proline content (only in the absence of drought) in plant leaves, whereas they decreased the concentrations of malondialdehyde. Irrespective of water stress, ASS1 significantly improved accumulation, total removal, bio-concentration factor and biological accumulation coefficient of metals (Cu, Zn and Ni), while decreased translocation factors of Cu. The effective colonization and survival in the rhizosphere and tissue interior assured improved plant growth and successful metal phytoremediation under DS. These results demonstrate the potential of serpentine endophytic bacterium ASS1 for protecting plants against abiotic stresses and helping plants to thrive in semiarid ecosystems and accelerate phytoremediation process in metal polluted soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Effect of humidity content and direction of the flow of reactant gases on water management in the 4-serpentine and 1-serpentine flow channel in a PEM (proton exchange membrane) fuel cell

    International Nuclear Information System (INIS)

    Khazaee, I.; Sabadbafan, H.

    2016-01-01

    The performance of a PEM (proton exchange membrane) fuel cell depends on design and operating parameters such as relative humidity, operation pressure, and number of channels and direction of the flow of reactant gases. In this study, a three-dimensional, two-phase model has been established to investigate the water management and performance of PEM fuel cell with rectangular geometry and 1-serpentine and 4-serpentine with parallel flow, counter flow and cross flow for hydrogen and oxygen. The numerical simulation was realized with a PEM fuel cell model based on the FLUENT. The active area of each cell is 24.8 cm 2 that its weight is 1300 gr. The material of the gas diffusion layer is carbon clothes, the membrane is nafion117 and the catalyst layer is a plane with 0.004 g cm −2 platinum. Pure hydrogen is used on the anode side and oxygen on the cathode side. Simulation results are obtained for voltage as a function of current density at different humidity. The simulation results are compared with the experimental data, and the agreement is found to be good. The results show that the cell performance at lower voltages increases with increasing humidity in cell with 4-Serpentine flow channel and also in cell with 1-Serpentine flow channel, cell performance at all voltages increases with increasing humidity. In cell with 4-Serpentine and parallel flow channel cell performance is better than counter and cross flow in low voltage and in cell with 1-Serpentine and parallel flow, performance is better than counter and cross flow in high voltage. - Highlights: • Investigation new geometries of a fuel cell. • The effect of geometry on current density, oxygen and water distribution. • The effect of humidity on current density, oxygen and water distribution. • Seeing the interacting and complex electrochemical phenomena.

  16. Geochemistry and geobiology of a present-day serpentinization site in California: The Cedars

    Science.gov (United States)

    Morrill, Penny L.; Kuenen, J. Gijs; Johnson, Orion J.; Suzuki, Shino; Rietze, Amanda; Sessions, Alex L.; Fogel, Marilyn L.; Nealson, Kenneth H.

    2013-05-01

    Ultra-basic (pH 11-12) reducing (-656 to -585 mV) groundwater springs discharging from serpentinized peridotite of The Cedars, CA, were investigated for their geochemistry and geobiology. The spring waters investigated were of meteoric origin; however, geochemical modeling suggests that there were two sources of groundwater, a shallow source with sufficient contact with The Cedars' peridotite body to be altered geochemically by serpentinization, and a deeper groundwater source that not only flows through the peridotite body but was also in contact with the marine sediments of the Franciscan Subduction Complex (FSC) below the peridotite body. We propose that the groundwater discharging from lower elevations (GPS1 and CS1) reflect the geochemistry of the deeper groundwater in contact with FSC, while groundwaters discharging from springs at higher elevations (NS1 and BSC) were a mixture of the shallow peridotite-only groundwater and the deeper groundwater that has been in contact with the FSC. Cell densities of suspended microbes within these waters were extremely low. In the NS1 and BSC spring fluids, cell densities ranged from 102 to 103 cells/ml, while suspended cells at GPS were lower than 10 cells/mL. However, glass slides incubated in the BSC and GPS1 springs for 2-3 weeks were colonized by cells with densities ranging from 106 to 107 cells/cm2 attached to their surfaces. All of the springs were very low (⩽1 μM) in several essential elements and electron acceptors (e.g. nitrate/ammonium, sulfate, and phosphate) required for (microbial) growth, which is not uncommon at sites of continental serpentinization. Gases rich in N2, H2, and CH4 were exsolving from the springs. The stable carbon isotope value (δ13CCH4 = -68 ± 0.6‰) and the CH4/C2+ (>103) of methane and other gaseous hydrocarbons exsolving from NS1 were typical of microbially sourced methane, whereas the isotope values and the CH4/C2+ of BSC and CS1 springs were more enriched in 13C and had CH4/C2

  17. Fumarolic minerals

    DEFF Research Database (Denmark)

    Balic Zunic, Tonci; Garavelli, Anna; Jakobsson, Sveinn Peter

    2016-01-01

    The fumarolic mineralogy of the Icelandic active volcanoes, the Tyrrhenian volcanic belt (Italy) and the Aegean active arc (Greece) is investigated, and literature data surveyed in order to define the characteristics of the European fumarolic systems. They show broad diversity of mineral...... associations, with Vesuvius and Vulcano being also among the world localities richest in mineral species. Volcanic systems, which show recession over a longer period, show fumarolic development from the hightemperature alkaline halide/sulphate, calcic sulphate or sulphidic parageneses, synchronous...... with or immediately following the eruptions, through mediumtemperature ammonium minerals, metal chlorides, or fluoride associations to the late low-temperature paragenesis dominated by sulphur, gypsum, alunogen, and other hydrous sulphates. The situation can be different in the systems that are not recessing but show...

  18. Mineral sands

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    This paper presents an outlook of the Australian mineral sand industry and covers the major operators. It is shown that conscious of an environmentally minded public, the Australian miners have led the way in the rehabilitation of mined areas. Moreover the advanced ceramic industry is generating exciting new perspectives for zircon producers and there is a noticeable growth in the electronic market for rare earths, but in long term the success may depend as much on environmental management and communication skills as on mining and processing skills

  19. SEMTAP (Serpentine End Match TApe program): The Easy Way to Program Your Numerically Controlled Router for the Production of SEM Joints

    Science.gov (United States)

    Ronald E. Coleman

    1977-01-01

    SEMTAP (Serpentine End Match TApe Program) is an easy and inexpensive method of programing a numerically controlled router for the manufacture of SEM (Serpentine End Matching) joints. The SEMTAP computer program allows the user to issue commands that will accurately direct a numerically controlled router along any SEM path. The user need not be a computer programer to...

  20. Nickeliferous minerals in the Cassiar Asbestos Deposit, Northern British Columbia (NTS 104/P/05) - Relevance for Nickel Exploration

    Czech Academy of Sciences Publication Activity Database

    Hora, Z. D.; Langrová, Anna; Pivec, E.

    2011-01-01

    Roč. 2010, 2011-1 (2011), s. 31-35 ISSN 0381-243X Institutional research plan: CEZ:AV0Z30130516 Keywords : Cassiar deposit * MINFILE 104P 005 * chrysolite asbestos * Cr-magnetite * nickel * Ni * heazlewoodite * serpentinization products * nickel minerals * awaruite Subject RIV: DB - Geology ; Mineralogy http://www.em.gov.bc.ca/Mining/Geoscience/PublicationsCatalogue/Fieldwork/Documents/2010/03_Hora_2010.pdf

  1. Concentration factors of uranium mineralization in VII depositional cycle of Shuixigou group, lower-middle Jurassic at Wukurqi uranium deposit, Yili basin

    International Nuclear Information System (INIS)

    Liu Taoyong

    2004-01-01

    Starting with the analysis on uranium mineralization, this paper emphatically discusses factors related to uranium concentration in VII depositional cycle, such as the structure, the paleoclimate, the lithofacies-paleogeography, the lithology, the hydrogeology, the geochemistry, and the content of effective reductant. The author suggests that key factors of uranium migration and concentration at Wukurqi uranium deposit are the existence of ore-hosting formation (sand body), the long-term recharge of oxygen and uranium-bearing groundwater, the existence of effective reductant in ore-hosting formation

  2. Deformation associated to exhumation of serpentinized mantle rocks in a fossil Ocean Continent Transition: The Totalp unit in SE Switzerland

    Science.gov (United States)

    Picazo, S.; Manatschal, G.; Cannat, M.; Andréani, M.

    2013-08-01

    Although the exhumation of ultramafic rocks in slow and ultraslow spreading Mid-Ocean Ridges and Ocean Continent Transitions (OCTs) has been extensively investigated, the deformation processes related to mantle exhumation are poorly constrained. In this paper we present a new geological map and a section across the exhumed serpentinized peridotites of the Totalp unit near Davos (SE Switzerland), and we propose that the Totalp unit is formed by two Alpine thrust sheets. Geological mapping indicates local exposure of a paleo-seafloor that is formed by an exhumed detachment surface and serpentinized peridotites. The top of the exhumed mantle rocks is made of ophicalcites that resulted from the carbonation of serpentine under static conditions at the seafloor. The ophicalcites preserve depositional contacts with Upper Jurassic to Lower Cretaceous pelagic sediments (Bernoulli and Weissert, 1985). These sequences did not exceed prehnite-pumpellyite metamorphic facies conditions, and locally escaped Alpine deformation. Thin mylonitic shear zones as well as foliated amphibole-bearing ultramafic rocks have been mapped. The age of these rocks and the link with the final exhumation history are yet unknown but since amphibole-bearing ultramafic rocks can be found as clasts in cataclasites related to the detachment fault, they pre-date detachment faulting. Our petrostructural study of the exhumed serpentinized rocks also reveals a deformation gradient from cataclasis to gouge formation within 150 m in the footwall of the proposed paleo-detachment fault. This deformation postdates serpentinization. It involves a component of plastic deformation of serpentine in the most highly strained intervals that has suffered pronounced grain-size reduction and a polyphase cataclastic overprint.

  3. Bone mineral accrual across growth in a mixed-ethnic group of children: are Asian children disadvantaged from an early age?

    Science.gov (United States)

    Burrows, Melonie; Baxter-Jones, Adam; Mirwald, Robert; Macdonald, Heather; McKay, Heather

    2009-05-01

    We investigated the contribution of ethnicity, physical activity, body composition, and calcium intake to bone accrual across 7 years of growth. We assessed 80 Caucasian and 74 Asian boys and 81 Caucasian and 64 Asian girls at baseline and retained 155 children across all 7 years. Ethnicity, physical activity, and calcium intake were assessed by questionnaire; fat mass, lean mass, and bone mineral content (BMC) of the whole body (WB), lumbar spine (LS), total proximal femur (PF(TOT)), and femoral neck (FN) were measured using DXA (Hologic QDR 4500). We aligned children on peak height velocity and utilized multilevel modeling to assess bone mineral accrual. Height and lean mass accounted for 51.8% and 44.1% of BMC accrual in children. There was a significant difference in physical activity, calcium intake, and lean mass between Asians and Caucasian boys and girls at baseline and conclusion (p accrual at the FN. In girls, Asians had significantly lower PF(TOT) and FN BMC. Calcium was a significant predictor of WB BMC accrual in boys and girls. In conclusion, our findings highlight the importance of accounting for ethnicity in pediatric studies. Physical activity, dietary calcium, and lean mass positively influence bone accrual and are lower in Asian compared to Caucasian children from a very young age.

  4. Petrography and mineral chemistry of metamorphosed mantle peridotites of Nain Ophiolite (Central Iran

    Directory of Open Access Journals (Sweden)

    Nargess Shirdashtzadeh

    2017-07-01

    Full Text Available Introduction Study of the petrology of the ophiolites as the relics of ancient oceanic lithosphere, is a powerful tool to reconstruct Earth’s history. Mantle peridotites have mostly undergone alteration and serpentinization to some extent. Thus, the relics of metamorphic signatures from the upper mantle and crustal processes from most of the peridotites have been ruined. Several recent papers deal with the mantle peridotites of Nain Ophiolite (e.g. Ghazi et al., 2010. However, no scientific work has been carried out on the metamorphosed mantle peridotites. The study area of the Darreh Deh that is located in the east of the Nain Ophiolite, is composed of huge massifs of metamorphosed mantle peridotites (i.e. lherzolite, clinopyroxene-bearing harzburgite, and harzburgite, and small volumes of dunite, characterized by darker color, higher topographic relief, smaller number of basic intrusives, lower serpentinization degree, and amphibolite-facies metamorphism. In this study, the petrography and mineralogy of metamorphosed peridotites in the Darreh Deh has been considered based on geochemical data. Geological Setting The Mesozoic ophiolitic mélange of Nain is located in the west of CEIM, along the Nain-Baft fault. As a part of a metamorphosed oceanic crust, it is mainly composed of harzburgite, lherzolite, dunite and their serpentinized varieties, chromitite, pyroxenite, gabbro, diabasic dike, spilitized pillow lava, plagiogranite, amphibolite, metaperidotites, schist, skarn, marble, rodingite, metachert and listwaenite (Shirdashtzadeh et al., 2010, 2014a, 2014b. Geochemical investigations indicate a suprasubduction zone in the eastern branch of the Neo-Tethys Ocean (Ghasemi and Talbot, 2006; Shirdashtzadeh et al., 2010, 2014a, 2014b. Materials and Methods Chemical analyses of mineral compositions were carried out using a JEOL JXA8800R wavelength-dispersive electron probe micro-analyzer (accelerating voltage of 15 kV and a beam current of 15 n

  5. Microbial Community Structure in a Serpentine-Hosted Abiotic Gas Seepage at the Chimaera Ophiolite, Turkey.

    Science.gov (United States)

    Neubeck, Anna; Sun, Li; Müller, Bettina; Ivarsson, Magnus; Hosgörmez, Hakan; Özcan, Dogacan; Broman, Curt; Schnürer, Anna

    2017-06-15

    The surface waters at the ultramafic ophiolitic outcrop in Chimaera, Turkey, are characterized by high pH values and high metal levels due to the percolation of fluids through areas of active serpentinization. We describe the influence of the liquid chemistry, mineralogy, and H 2 and CH 4 levels on the bacterial community structure in a semidry, exposed, ultramafic environment. The bacterial and archaeal community structures were monitored using Illumina sequencing targeting the 16S rRNA gene. At all sampling points, four phyla, Proteobacteria , Actinobacteria , Chloroflexi , and Acidobacteria , accounted for the majority of taxa. Members of the Chloroflexi phylum dominated low-diversity sites, whereas Proteobacteria dominated high-diversity sites. Methane, nitrogen, iron, and hydrogen oxidizers were detected as well as archaea and metal-resistant bacteria. IMPORTANCE Our study is a comprehensive microbial investigation of the Chimaera ophiolite. DNA has been extracted from 16 sites in the area and has been studied from microbial and geochemical points of view. We describe a microbial community structure that is dependent on terrestrial, serpentinization-driven abiotic H 2 , which is poorly studied due to the rarity of these environments on Earth. Copyright © 2017 Neubeck et al.

  6. A novel sandwich differential capacitive accelerometer with symmetrical double-sided serpentine beam-mass structure

    International Nuclear Information System (INIS)

    Xiao, D B; Li, Q S; Hou, Z Q; Wang, X H; Chen, Z H; Xia, D W; Wu, X Z

    2016-01-01

    This paper presents a novel differential capacitive silicon micro-accelerometer with symmetrical double-sided serpentine beam-mass sensing structure and glass–silicon–glass sandwich structure. The symmetrical double-sided serpentine beam-mass sensing structure is fabricated with a novel pre-buried mask fabrication technology, which is convenient for manufacturing multi-layer sensors. The glass–silicon–glass sandwich structure is realized by a double anodic bonding process. To solve the problem of the difficulty of leading out signals from the top and bottom layer simultaneously in the sandwich sensors, a silicon pillar structure is designed that is inherently simple and low-cost. The prototype is fabricated and tested. It has low noise performance (the peak to peak value is 40 μg) and μg-level Allan deviation of bias (2.2 μg in 1 h), experimentally demonstrating the effectiveness of the design and the novel fabrication technology. (paper)

  7. Serpentinization as a source of energy at the origin of life.

    Science.gov (United States)

    Russell, M J; Hall, A J; Martin, W

    2010-12-01

    For life to have emerged from CO₂, rocks, and water on the early Earth, a sustained source of chemically transducible energy was essential. The serpentinization process is emerging as an increasingly likely source of that energy. Serpentinization of ultramafic crust would have continuously supplied hydrogen, methane, minor formate, and ammonia, as well as calcium and traces of acetate, molybdenum and tungsten, to off-ridge alkaline hydrothermal springs that interfaced with the metal-rich carbonic Hadean Ocean. Silica and bisulfide were also delivered to these springs where cherts and sulfides were intersected by the alkaline solutions. The proton and redox gradients so generated represent a rich source of naturally produced chemiosmotic energy, stemming from geochemistry that merely had to be tapped, rather than induced, by the earliest biochemical systems. Hydrothermal mounds accumulating at similar sites in today's oceans offer conceptual and experimental models for the chemistry germane to the emergence of life, although the ubiquity of microbial communities at such sites in addition to our oxygenated atmosphere preclude an exact analogy. Published 2010. This article is a US Government work and is in the public domain in the USA.

  8. Serpentine soils affect heavy metal tolerance but not genetic diversity in a common Mediterranean ant.

    Science.gov (United States)

    Frizzi, Filippo; Masoni, Alberto; Çelikkol, Mine; Palchetti, Enrico; Ciofi, Claudio; Chelazzi, Guido; Santini, Giacomo

    2017-08-01

    Natural habitats with serpentine soils are rich in heavy metal ions, which may significantly affect ecological communities. Exposure to metal pollutants results, for instance, in a reduction of population genetic diversity and a diffused higher tolerance towards heavy metals. In this study, we investigated whether chronic exposure to metals in serpentine soils affect accumulation patterns, tolerance towards metal pollutants, and genetic diversity in ants. In particular, we studied colonies of the common Mediterranean ant, Crematogaster scutellaris, along a contamination gradient consisting of two differently contaminated forests and a reference soil with no geogenic contamination. We first evaluated the metal content in both soil and ants' body. Then, we tested for tolerance towards metal pollutants by evaluating the mortality of ants fed with nickel (Ni) solutions of increasing concentrations. Finally, differences in genetic diversity among ants from different areas were assessed using eight microsatellite loci. Interestingly, a higher tolerance to nickel solutions was found in ants sampled in sites with intermediate levels of heavy metals. This may occur, because ants inhabiting strongly contaminated areas tend to accumulate higher amounts of contaminants. Additional ingestion of toxicants beyond the saturation threshold would lead to death. There was no difference in the genetic diversity among ant colonies sampled in different sites. This was probably the result of queen mediated gene flow during nuptial flights across uncontaminated and contaminated areas of limited geographical extent. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Toxic element profiles in selected medicinal plants growing on serpentines in Bulgaria.

    Science.gov (United States)

    Pavlova, Dolja; Karadjova, Irina

    2013-12-01

    Populations of medicinal plants growing on serpentines and their respective soils were analyzed for Fe, Ni, Mn, Cr, Co, Cd, Cu, Zn, and Pb using inductively coupled plasma atomic emission spectrometry. Aqua regia extraction and 0.43 M acetic acid extraction were used for the quantification of pseudototal and bioavailable fractions, respectively, of elements in soil and nitric acid digestion for determination of total element content in plants. Screening was performed to (1) document levels of toxic metals in herbs extensively used in preparation of products and standardized extracts, (2) compare accumulation abilities of ferns and seed plants, and (3) estimate correlations between metal content in plants and their soils. The toxic element content of plants varied from site to site on a large scale. The concentrations of Fe and Ni were elevated while those of Cu, Zn, and Pb were close to average values usually found in plants. The highest concentrations for almost all elements were measured in both Teucrium species. Specific differences in metal accumulation between ferns and seed plants were not recorded. The investigated species are not hyperaccumulators but can accumulate toxic elements, in some cases exceeding permissible levels proposed by the World Health Organization and European Pharmacopoeia. The harvesting of medicinal plants from serpentines could be hazardous to humans.

  10. Turbulence characteristics and mixing performances of viscoelastic fluid flow in a serpentine microchannel

    International Nuclear Information System (INIS)

    Tatsumi, K; Takeda, Y; Nakabe, K; Suga, K

    2011-01-01

    Flow velocity measurement and visualization using particle image velocimetry and fluorescent dye were carried out for a viscoelastic fluid flow in a serpentine microchannel for the purpose to quantitatively evaluate the unsteady flow characteristics that is observed even under very low Reynolds number regime due to the combined effect of the viscoelastic fluid properties and the channel shape. Sucrose water solution (Newtonian fluid) and the polyacrylamide-sucrose water solution (viscoelastic fluid) were used as working fluids. The mixing performance markedly increased when the Reynolds number exceeded a certain value in the polyacrylamide solution case. The single-point, cross-sectional and two-dimensional velocity distributions showed that low frequency fluctuation was produced in the polyacrylamide solution case. Particularly large fluctuation in the channel spanwise direction was observed in the upstream area of the serpentine channel. On the other hand, the amplitude of the fluctuation decreased in the downstream region. The fluctuation in the upstream region is believed to be generated by the flow instability at the curved part of the channel, while the fluctuations in the downstream area were attributed to the local instability and the vortices provided from the upstream region.

  11. Hydrothermal minerals

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.

    flux. Circulation of seawater through the oceanic crust and upper mantle gives rise to a complex series of physical and chemical reactions that lead to the 1) formation of seafloor mineral deposits; 2) alteration of oceanic crust; 3) control... temperature in the high-temperature reaction zone near the heat source. Important parameters in determining the high- temperature fluid composition are • pressure, • temperature, • water/rock ratio, • rock composition, • recharge fluid...

  12. A segmented cell approach for studying the effects of serpentine flow field parameters on PEMFC current distribution

    International Nuclear Information System (INIS)

    Reshetenko, Tatyana V.; Bender, Guido; Bethune, Keith; Rocheleau, Richard

    2013-01-01

    Highlights: ► Effects of a flow field design on PEMFC were investigated. ► A segmented cell was used to study 6- and 10-channel serpentine flow fields. ► 10-Channel flow field improved a fuel cell's performance at high current. ► Performance distribution was more uniform for 10-channel than for 6-channel flow field. ► The performance improvement was due to an increased pressure drop. -- Abstract: A serpentine flow field is a commonly used design in proton exchange membrane fuel cells (PEMFCs). Consequently, optimization of the flow field parameters is critically needed. A segmented cell system was used to study the impact of the flow field's parameters on the current distribution in a PEMFC, and the data obtained were analyzed in terms of voltage overpotentials. 6-Channel and 10-channel serpentine flow field designs were investigated. At low current the segments performance was found to slightly decrease for a 10-channel serpentine flow field. However, increasing the number of channels increased the fuel cell performance when operating at high current and the cell performance became more uniform downstream. The observed improvement in fuel cell performance was attributed to a decrease in mass transfer voltage losses (permeability and diffusion), due to an increased pressure drop. Spatially distributed electrochemical impedance spectroscopy (EIS) data showed differences in the local segment impedance response and confirmed the performance distribution and the impact of the flow field design

  13. Bringing Together Evolution on Serpentine and Polyploidy: Spatiotemporal History of the Diploid-Tetraploid Complex of Knautia arvensis (Dipsacaceae)

    Czech Academy of Sciences Publication Activity Database

    Kolář, Filip; Fér, T.; Štech, M.; Trávníček, Pavel; Dušková, E.; Schönswetter, P.; Suda, Jan

    2012-01-01

    Roč. 7, č. 7 (2012), e39988 E-ISSN 1932-6203 R&D Projects: GA AV ČR KJB600050812; GA AV ČR(CZ) KJB601110627 Institutional research plan: CEZ:AV0Z6005908 Institutional support: RVO:67985939 Keywords : serpentine spetiation * Knautia arvensis * polyploidy Subject RIV: EF - Botanics Impact factor: 3.730, year: 2012

  14. Arbuscular mycorrhizal symbiosis on serpentine soils: the effect of native fungal communities on different Knautia arvensis ecotypes

    Czech Academy of Sciences Publication Activity Database

    Doubková, Pavla; Suda, Jan; Sudová, Radka

    2011-01-01

    Roč. 345, 1-2 (2011), s. 325-338 ISSN 0032-079X R&D Projects: GA AV ČR KJB600050812 Institutional research plan: CEZ:AV0Z60050516 Keywords : arbuscular mycorrhiza * serpentine soils * edaphic stress Subject RIV: EF - Botanics Impact factor: 2.733, year: 2011

  15. 77 FR 47089 - Public Land Order No. 7795; Withdrawal of Public Lands, Clear Creek Serpentine Area of Critical...

    Science.gov (United States)

    2012-08-07

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLCAC09000, 16100000.DQ; CACA 051408] Public Land Order No. 7795; Withdrawal of Public Lands, Clear Creek Serpentine Area of Critical Environmental Concern; California AGENCY: Bureau of Land Management, Interior. ACTION: Public Land Order. SUMMARY: This...

  16. B-type olivine fabric induced by low temperature dissolution creep during serpentinization and deformation in mantle wedge

    Science.gov (United States)

    Liu, Wenlong; Zhang, Junfeng; Barou, Fabrice

    2018-01-01

    The B-type olivine fabric (i.e., the [010] axes subnormal to foliation and the [001] axes subparallel to the lineation) has been regarded as an important olivine fabric for interpreting global trench-parallel S-wave polarization in fore-arc regions. However, strong serpentinization and cold temperature environment in the mantle wedge should inhibit development of the B-type olivine fabric that requires high temperature to activate solid-state plastic deformation. Here we report fabrics of olivine and antigorite generated at low temperatures (300-370 °C) during serpentinization in a fossil mantle wedge of the Val Malenco area, Central Alps. Olivine in the serpentine matrix develops a pronounced B-type fabric, while antigorite in the same matrix displays a strong crystallographic preferred orientation (CPO) with the (001) planes and the [010] axes subparallel to foliation and lineation, respectively. The following evidence leads to the conclusion that the B-type olivine fabric results from dissolution creep assisted by grain boundary sliding (GBS) and grain rotation, rather than solid-state plastic deformation: (1) serpentinization took place at low temperatures and a fluid-enriched environment, ideal for dissolution-precipitation creep; (2) the voids and zigzag boundaries along the interface between antigorite and olivine suggest a fluid dissolution reaction; (3) the primary coarse olivine develops a nearly random fabric, indicating the B-type fabrics in the fine-grained olivine may not be inherited fabrics. These results document for the first time the B-type olivine CPO formed by dissolution creep at low temperatures during serpentinization and provide a mechanism to reconcile petrofabric observations with geophysical observations of trench parallel fast S-wave seismic anisotropy in fore-arc mantle wedge regions.

  17. Low temperature dissolution creep induced B-type olivine fabric during serpentinization and deformation in mantle wedge

    Science.gov (United States)

    Liu, W.; Zhang, J.

    2017-12-01

    The B-type olivine fabric (i.e., the [010]ol axes subnormal to foliation and the [001]ol axes subparallel to the lineation) has been regarded as an important olivine fabric for interpreting global trench-parallel S-wave polarization in fore-arc regions. However, strong serpentinization and cold temperature environment in the mantle wedge should inhibit development of the B-type olivine fabric that requires high temperature to activate solid-state plastic deformation. Here we report fabrics of olivine and antigorite generated at low temperatures (300-370 oC) during serpentinization in a fossil mantle wedge of the Val Malenco area, Central Alps. Olivine in the serpentine matrix develops a pronounced B-type fabric, while antigorite in the same matrix displays a strong crystallographic orientation (CPO) with the (001) and the [010] subparallel to foliation and lineation, respectively. The following evidence leads to the conclusion that the B-type olivine fabric is resulted from dissolution creep assisted by grain boundaries sliding (GBS) and grain rotation, rather than solid-state plastic deformation: (1) serpentinization took place at low temperatures and a fluid-enriched environment, ideal for dissolution-precipitation creep; (2) the voids and zigzag boundaries along the interface between antigorite and olivine suggest a fluid dissolution reaction; (3) the primary coarse olivine develops a nearly random fabric, indicating the B-type fabrics in the fine-grained olivine can't be inherited fabrics. These results document for the first time the B-type olivine CPO formed by dissolution creep at low temperatures during serpentinization and provide a mechanism to reconcile petrofabric observations with geophysical observations of trench parallel fast S-wave seismic anisotropy in fore-arc mantle wedge regions.

  18. The Correlation Between Porosity, Density and Degree of Serpentinization in Ophiolites from Point Sal, California: Implications for Strength of Oceanic Lithosphere

    Science.gov (United States)

    Karrasch, A. K.; Farough, A.; Lowell, R. P.

    2017-12-01

    Hydration and serpentinization of oceanic lithosphere influences its strength and behavior under stress. Serpentine content is the limiting factor in deformation and the correlation between crustal strength and the degree of serpentinization is not linear. Escartin et al., [2001] shows that the presence of only 10% serpentine results in a nominally non-dilatant mode of brittle deformation and reduces the strength of peridotites dramatically. In this study, we measured density and porosity of ophiolite samples from Point Sal, CA that had various degrees of serpentinization. The densities ranged between 2500- 3000 kg/m3 and porosities ranged between 2.1-4.8%. The degree of serpentinization was estimated from mineralogical analysis, and these data were combined with that of 4 other samples analyzed by Farough et al., [2016], which were obtained from various localities. The degree of serpentinization varied between 0.6 and 40%. We found that degree of serpentinization was inversely correlated with density with a slope of 7.25 (kg/m3)/%. Using Horen et al., [1996] models, estimated P-wave velocity of the samples ranged between 6.75-7.90 km/s and S-wave velocity ranged between 3.58-4.35 km/s. There were no distinguishable difference in the results between olivine-rich or pyroxene-rich samples. These results, along with correlations to strength and deformation style, can be used as a reference for mechanical properties of the crust at depth, analysis of deep drill cores and to estimate the rate of weakening of the oceanic crust after the onset of serpentinization reactions.

  19. Commentary: Ex Situ Aqueous Mineral Carbonation

    Energy Technology Data Exchange (ETDEWEB)

    Gadikota, Greeshma, E-mail: gadikota@princeton.edu [Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ (United States)

    2016-05-26

    CO{sub 2} conversion to calcium and magnesium carbonates has garnered considerable attention since it is a thermodynamically downhill pathway to safely and permanently sequester large quantities of CO{sub 2}. This seminal work performed at The National Energy Technology Laboratory in Albany (NETL-Albany) reports the conversion of calcium- and magnesium-bearing silicate minerals, such as olivine [(Mg, Fe){sub 2}SiO{sub 4}], wollastonite (CaSiO{sub 3}), and serpentine [Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}], as they are reacted with CO{sub 2} in an aqueous environment to form magnesium or calcium carbonates. This paper discusses various pretreatment methods of the starting materials, such as grinding or heat treatment of hydroxylated Mg silicates, to enhance the reaction kinetics. The effects of various chemical additives (e.g., NaCl and NaHCO{sub 3}), and reaction parameters, such as temperature, pressure, and reaction time, on the conversion are investigated. Feasibility assessments and energy and economic analyses of the direct carbonation of calcium- and magnesium-bearing minerals are presented.

  20. Chlorellestadite, Ca5(SiO4)1.5(SO4)1.5Cl, a new ellestadite- group mineral from the Shadil-Khokh volcano, South Ossetia

    Science.gov (United States)

    Środek, Dorota; Galuskina, Irina O.; Galuskin, Evgeny; Dulski, Mateusz; Książek, Maria; Kusz, Joachim; Gazeev, Viktor

    2018-05-01

    Chlorellestadite (IMA2017-013), ideally Ca5(SiO4)1.5(SO4)1.5Cl, the Cl-end member of the ellestadite group was discovered in a calcium-silicate xenolith in rhyodacite lava from the Shadil Khokh volcano, Greater Caucasus, South Ossetia. Chlorellestadite forms white, tinged with blue or green, elongate crystals up to 0.2-0.3 mm in length. Associated minerals include spurrite, larnite, chlormayenite, rondorfite, srebrodolskite, jasmundite and oldhamite. The empirical crystal chemical formula of the holotype specimen is Ca4.99Na0.01(SiO4)1.51(SO4)1.46(PO4)0.03(Cl0.61OH0.21F0.11)Σ0.93. Unit-cell parameters of chlorellestadite are: P63/m, a = 9.6002(2), c = 6.8692(2) Å, V = 548.27(3)Å3, Z = 2. Chlorellestadite has a Mohs hardness of 4-4.5 and a calculated density of 3.091 g/cm3. The cleavage is indistinct, and the mineral shows irregular fracture. The Raman spectrum of chlorellestadite is similar to the spectra of other ellestadite group minerals, with main bands located at 267 cm-1 (Ca-O vibrations), and between 471 and 630 cm-1 (SiO4 4- and SO4 2- bending vibrations) and 850-1150 cm-1 (SiO4 4- and SO4 2- stretching modes). Chlorellestadite forms in xenoliths of calcium-silicate composition when they are exposed to Cl-bearing volcanic exhalations at about 1000 °C under low pressure conditions.

  1. Numerical study on channel size effect for proton exchange membrane fuel cell with serpentine flow field

    International Nuclear Information System (INIS)

    Wang Xiaodong; Yan Weimon; Duan Yuanyuan; Weng Fangbor; Jung Guobin; Lee Chiyuan

    2010-01-01

    This work numerically investigates the effect of the channel size on the cell performance of proton exchange membrane (PEM) fuel cells with serpentine flow fields using a three-dimensional, two-phase model. The local current densities in the PEM, oxygen mass flow rates and liquid water concentrations at the interface of the cathode gas diffusion layer and catalyst layer were analyzed to understand the channel size effect. The predictions show that smaller channel sizes enhance liquid water removal and increase oxygen transport to the porous layers, which improve cell performance. Additionally, smaller channel sizes also provide more uniform current density distributions in the cell. However, as the channel size decreases, the total pressure drops across the cell increases, which leads to more pump work. With taking into account the pressure losses, the optimal cell performance occurs for a cell with a flow channel cross-sectional area of 0.535 x 0.535 mm 2 .

  2. Early Thermal History of Rhea: The Role of Serpentinization and Liquid State Convection

    Science.gov (United States)

    Czechowski, Leszek; Łosiak, Anna

    2016-12-01

    Early thermal history of Rhea is investigated. The role of the following parameters of the model is investigated: time of beginning of accretion, tini, duration of accretion, tac, viscosity of ice close to the melting point, η0, activation energy in the formula for viscosity, E, thermal conductivity of silicate component, ksil, ammonia content, XNH3, and energy of serpentinization, cserp. We found that tini and tac are crucial for evolution. All other parameters are also important, but no dramatic differences are found for realistic values. The process of differentiation is also investigated. It is found that liquid state convection could delay the differentiation for hundreds of My. The results are confronted with observational data from Cassini spacecraft. It is possible that differentiation is fully completed but the density of formed core is close to the mean density. If this interpretation is correct, then Rhea could have accreted any time before 3-4 My after formation of CAI.

  3. Performance of Polycrystalline Photovoltaic and Thermal Collector (PVT on Serpentine-Parallel Absorbers Design

    Directory of Open Access Journals (Sweden)

    Mustofa Mustofa

    2017-03-01

    Full Text Available This paper presents the performance of an unglazed polycrystalline photovoltaic-thermal PVT on 0.045 kg/s mass flow rate. PVT combine photovoltaic modules and solar thermal collectors, forming a single device that receive solar radiation and produces heat and electricity simultaneously. The collector figures out serpentine-parallel tubes that can prolong fluid heat conductivity from morning till afternoon. During testing, cell PV, inlet and outlet fluid temperaturs were recorded by thermocouple digital LM35 Arduino Mega 2560. Panel voltage and electric current were also noted in which they were connected to computer and presented each second data recorded. But, in this performance only shows in the certain significant time data. This because the electric current was only noted by multimeter device not the digital one. Based on these testing data, average cell efficieny was about 19%, while thermal efficiency of above 50% and correspondeng cell efficiency of 11%, respectively

  4. Performance of Polycrystalline Photovoltaic and Thermal Collector (PVT on Serpentine-Parallel Absor

    Directory of Open Access Journals (Sweden)

    Mustofa

    2015-10-01

    Full Text Available This paper presents the performance of an unglazed polycrystalline photovoltaic-thermal PVT on 0.045 kg/s mass flow rate. PVT combine photovoltaic modules and solar thermal collectors, forming a single device that receive solar radiation and produces heat and electricity simultaneously. The collector figures out serpentine-parallel tubes that can prolong fluid heat conductivity from morning till afternoon. During testing, cell PV, inlet and outlet fluid temperatures were recorded by thermocouple digital LM35 Arduino Mega 2560. Panel voltage and electric current were also noted in which they were connected to computer and presented each second data recorded. But, in this performance only shows in the certain significant time data. This because the electric current was only noted by multimeter device not the digital one. Based on these testing data, average cell efficiency was about 19%, while thermal efficiency of above 50% and correspondent cell efficiency of 11%, respectively.

  5. Integrated axial and tangential serpentine cooling circuit in a turbine airfoil

    Science.gov (United States)

    Lee, Ching-Pang; Jiang, Nan; Marra, John J; Rudolph, Ronald J; Dalton, John P

    2015-05-05

    A continuous serpentine cooling circuit forming a progression of radial passages (44, 45, 46, 47A, 48A) between pressure and suction side walls (52, 54) in a MID region of a turbine airfoil (24). The circuit progresses first axially, then tangentially, ending in a last radial passage (48A) adjacent to the suction side (54) and not adjacent to the pressure side (52). The passages of the axial progression (44, 45, 46) may be adjacent to both the pressure and suction side walls of the airfoil. The next to last radial passage (47A) may be adjacent to the pressure side wall and not adjacent to the suction side wall. The last two radial passages (47A, 48A) may be longer along the pressure and suction side walls respectively than they are in a width direction, providing increased direct cooling surface area on the interiors of these hot walls.

  6. Evaluation of ilmenite serpentine concrete and ordinary concrete as nuclear reactor shielding

    International Nuclear Information System (INIS)

    Abulfaraj, W.H.; Kamal, S.M.

    1994-01-01

    The present study involves adapting a formal decision methodology to the selection of alternative nuclear reactor concrete shielding. Multiattribute utility theory is selected to accommodate decision maker's preferences. Multiattribute utility theory (MAU) is here employed to evaluate two appropriate nuclear reactor shielding concretes in terms of effectiveness to determine the optimal choice in order to meet the radiation protection regulations. These concretes are Ordinary concrete (O.C.) and Illmenite Serpentile concrete (I.S.C.). These are normal weight concrete and heavy weight heat resistive concrete, respectively. The effectiveness objective of the nuclear reactor shielding is defined and structured into definite attributes and subattributes to evaluate the best alternative. Factors affecting the decision are dose received by reactor's workers, the material properties as well as cost of concrete shield. A computer program is employed to assist in performing utility analysis. Based upon data, the result shows the superiority of Ordinary concrete over Illmenite Serpentine concrete. (Author)

  7. Two-Dimensional Numerical Study on the Migration of Particle in a Serpentine Channel

    Directory of Open Access Journals (Sweden)

    Yi Liu

    2018-01-01

    Full Text Available In this work, the momentum exchange scheme-based lattice Boltzmann method is adopted to numerically study the migration of a circular particle in a serpentine channel for the range of 20 ≤ Re ≤ 120. The effects of the Reynolds number, particle density, and the initial particle position are taken into account. Numerical results include the streamlines, particle trajectories, and final equilibrium positions. Close attention is also paid to the time it takes for the particle to travel in the channel. It has been found that the particle is likely to migrate to a similar equilibrium position irrespective of its initial position when Re is large. Furthermore, there exists a critical solid-to-fluid density ratio for which the particle travels fastest in the channel.

  8. Carbon K-edge spectra of carbonate minerals.

    Science.gov (United States)

    Brandes, Jay A; Wirick, Sue; Jacobsen, Chris

    2010-09-01

    Carbon K-edge X-ray spectroscopy has been applied to the study of a wide range of organic samples, from polymers and coals to interstellar dust particles. Identification of carbonaceous materials within these samples is accomplished by the pattern of resonances in the 280-320 eV energy region. Carbonate minerals are often encountered in the study of natural samples, and have been identified by a distinctive resonance at 290.3 eV. Here C K-edge and Ca L-edge spectra from a range of carbonate minerals are presented. Although all carbonates exhibit a sharp 290 eV resonance, both the precise position of this resonance and the positions of other resonances vary among minerals. The relative strengths of the different carbonate resonances also vary with crystal orientation to the linearly polarized X-ray beam. Intriguingly, several carbonate minerals also exhibit a strong 288.6 eV resonance, consistent with the position of a carbonyl resonance rather than carbonate. Calcite and aragonite, although indistinguishable spectrally at the C K-edge, exhibited significantly different spectra at the Ca L-edge. The distinctive spectral fingerprints of carbonates provide an identification tool, allowing for the examination of such processes as carbon sequestration in minerals, Mn substitution in marine calcium carbonates (dolomitization) and serpentinization of basalts.

  9. Carbon K-edge Spectra of Carbonate Minerals

    Energy Technology Data Exchange (ETDEWEB)

    Brandes, J.; Wirick, S; Jacobsen, C

    2010-01-01

    Carbon K-edge X-ray spectroscopy has been applied to the study of a wide range of organic samples, from polymers and coals to interstellar dust particles. Identification of carbonaceous materials within these samples is accomplished by the pattern of resonances in the 280-320 eV energy region. Carbonate minerals are often encountered in the study of natural samples, and have been identified by a distinctive resonance at 290.3 eV. Here C K-edge and Ca L-edge spectra from a range of carbonate minerals are presented. Although all carbonates exhibit a sharp 290 eV resonance, both the precise position of this resonance and the positions of other resonances vary among minerals. The relative strengths of the different carbonate resonances also vary with crystal orientation to the linearly polarized X-ray beam. Intriguingly, several carbonate minerals also exhibit a strong 288.6 eV resonance, consistent with the position of a carbonyl resonance rather than carbonate. Calcite and aragonite, although indistinguishable spectrally at the C K-edge, exhibited significantly different spectra at the Ca L-edge. The distinctive spectral fingerprints of carbonates provide an identification tool, allowing for the examination of such processes as carbon sequestration in minerals, Mn substitution in marine calcium carbonates (dolomitization) and serpentinization of basalts.

  10. Early Mars serpentinization-derived CH4 reservoirs, H2 induced warming and paleopressure evolution

    Science.gov (United States)

    Lasue, J.; Chassefiere, E.; Langlais, B.; Quesnel, Y.

    2016-12-01

    CH4 has been observed on Mars both by remote sensing and in situ during the past 15 years. Early Mars serpentinization is one possible abiotic mechanism that could not only produce methane, but also explain the observed Martian remanent magnetic field. Assuming a cold early Mars, a cryosphere could trap such CH4 as clathrates in stable form at depth. We recently estimated the maximum storage capacity of such clathrate layer to be about 2x1019 to 2x1020 moles of methane. Such reservoirs may be stable or unstable, depending on many factors that are poorly constrained: major and sudden geological events such as the Tharsis bulge formation, the Hellas impact or the martian polar wander, could have destabilized the clathrates early in the history of the planet and released large quantities of gas in the atmosphere. Here we estimate the associated amounts of serpentinization-derived CH4 stored in the cryosphere that have been released to the atmosphere at the end of the Noachian and the beginning of the Hesperian. Due to rapid clathrate dissociation and photochemical conversion of CH4 to H2, these episodes of massive CH4 release may have resulted in transient H2-rich atmospheres, at typical levels of 10-20% in a background 1-2 bar CO2 atmosphere. We propose that the early Mars cryosphere had a sufficient CH4 storage capacity to have maintained H2-rich transient atmospheres during a total time period up to several Myr or tens of Myr, having potentially contributed - by collision-induced heating effect of atmospheric H2 - to the formation of valley networks during the late Noachian and early Hesperian.

  11. Channel geometric scales effect on performance and optimization for serpentine proton exchange membrane fuel cell (PEMFC)

    Science.gov (United States)

    Youcef, Kerkoub; Ahmed, Benzaoui; Ziari, Yasmina; Fadila, Haddad

    2017-02-01

    A three dimensional computational fluid dynamics model is proposed in this paper to investigate the effect of flow field design and dimensions of bipolar plates on performance of serpentine proton exchange membrane fuel cell (PEMFC). A complete fuel cell of 25 cm2 with 25 channels have been used. The aim of the work is to investigate the effect of flow channels and ribs scales on overall performance of PEM fuel cell. Therefore, geometric aspect ratio parameter defined as (width of flow channel/width of rib) is used. Influences of the ribs and openings current collector scales have been studied and analyzed in order to find the optimum ratio between them to enhance the production of courant density of PEM fuel cell. Six kind of serpentine designs have been used in this paper included different aspect ratio varying from 0.25 to 2.33 while the active surface area and number of channels are keeping constant. Aspect ratio 0.25 corresponding of (0.4 mm channel width/ 1.6mm ribs width), and Aspect ratio2.33 corresponding of (0.6 mm channel width/ 1.4mm ribs width. The results show that the best flow field designs (giving the maximum density of current) are which there dimensions of channels width is minimal and ribs width is maximal (Γ≈0.25). Also decreasing width of channels enhance the pressure drop inside the PEM fuel cell, this causes an increase of gazes velocity and enhance convection process, therefore more power generation.

  12. Organic Minerals in the Origin of Life

    Science.gov (United States)

    Benner, S.; Biondi, E.; Kim, H. J.

    2017-12-01

    Models for the origin of life are plagued by fundamental problems that, due to their difficulty, are called "paradoxes". One of these, known to anyone who has ever worked in a kitchen, is that organics, when given energy and left to itself, does not generate life. Rather, organics devolve to give tarry mixtures that become increasingly complex and increasingly less likely to support life (like asphalt). However, even if those mixtures escape devolution to create something useful for Darwinism, like building blocks for RNA, the water in which they must work is corrosive, leading to their destruction. Even if RNA is created, it is itself easily degraded. One current trend to manage those paradoxes turns to minerals in environments on early Earth. Inorganic minerals containing borate have now been shown to prevent the destruction of ribose (the R in RNA) and other carbohydrates essential for early Earth. Evaporite desert basins supplied with aqueous runoff from tourmaline-containing basalts are ideal environments for forming borate minerals, especially if they are made alkaline by serpentinizing peridotite. In the evaporite environments, drying cycles mitigate the destructive capability of water. Further, we have shown that phosphate is segregated from calcium (avoiding formation of relatively unreacted apatites) if magnesium and borate are present. Further, a common magnesium borophosphate (luneburgite) not only makes phosphate available for prebiotic synthesis, but selectively phosphorylates RNA building blocks as it releases borate to stabilize them against further degradation. Finally, a variety of minerals bind and stabilize RNA itself. Research in this area has also discovered organic minerals that might have been relevant to the origins of life on Earth. Such minerals are scarce on Earth today, since they are easily consumed by microbial communities. However, on a prebiotic Earth, organic minerals could have stored organic species as intermediates towards our

  13. Carbon Isotope Systematics in Mineral-Catalyzed Hydrothermal Organic Synthesis Processes at High Temperature and Pressures

    Science.gov (United States)

    Fu, Qi; Socki, R. A.; Niles, Paul B.

    2011-01-01

    Observation of methane in the Martian atmosphere has been reported by different detection techniques. Reduction of CO2 and/or CO during serpentization by mineral surface catalyzed Fischer-Tropsch Type (FTT) synthesis may be one possible process responsible for methane generation on Mars. With the evidence a recent study has discovered for serpentinization in deeply buried carbon rich sediments, and more showing extensive water-rock interaction in Martian history, it seems likely that abiotic methane generation via serpentinization reactions may have been common on Mars. Experiments involving mineral-catalyzed hydrothermal organic synthesis processes were conducted at 750 C and 5.5 Kbars. Alkanes, alcohols and carboxylic acids were identified as organic compounds. No "isotopic reversal" of delta C-13 values was observed for alkanes or carboxylic acids, suggesting a different reaction pathway than polymerization. Alcohols were proposed as intermediaries formed on mineral surfaces at experimental conditions. Carbon isotope data were used in this study to unravel the reaction pathways of abiotic formation of organic compounds in hydrothermal systems at high temperatures and pressures. They are instrumental in constraining the origin and evolution history of organic compounds on Mars and other planets.

  14. Potential autotrophic metabolisms in ultra-basic reducing springs associated with present-day continental serpentinization

    Science.gov (United States)

    Morrill, P. L.; Miles, S.; Kohl, L.; Kavanagh, H.; Ziegler, S. E.; Brazelton, W. J.; Schrenk, M. O.

    2013-12-01

    Ultra-basic reducing springs at continental sites of serpentinization act as windows into the biogeochemistry of this subsurface exothermic environment rich in H2 and CH4 gases. Biogeochemical carbon transformations in these systems are of interest because serpentinization creates conditions that are amenable to abiotic and biotic reduction of carbon. However, little is known about the metabolic capabilities of the microorganisms that live in this environment. To determine the potential for autotrophic metabolisms, bicarbonate and CO substrate addition microcosm experiments were performed using water and sediment from an ultra-basic reducing spring in the Tablelands, Newfoundland, Canada, a site of present-day continental serpentinization. CO was consistently observed to be utilized in the Live but not the Killed controlled replicates amended with 10% 13C labelled CO and non-labelled (natural C isotope abundance) CO. In the Live CO microcosms with natural C isotope abundance, the residual CO became enriched in 13C (~10 ‰) consistent with a decrease in the fraction of CO remaining. In the Killed CO controlled replicates with natural C isotope abundance the CO showed little 13C enrichment (~1.3 ‰). The data from the Live CO microcosms were well described by a Rayleigh isotopic distillation model, yielding an isotopic enrichment factor for microbial CO uptake of 15.7 ×0.5 ‰ n=2. These data suggest that there was microbial CO utilization in these experiments. The sediment and water from the 13C-labelled and non-labelled, Live and Killed microcosms were extracted for phospholipid fatty acids (PLFAs) to determine changes in community composition between treatments as well as to determine the microbial uptake of CO. The difference in community composition between the Live and Killed microcosms was not readily resolvable based on PLFA distributions. Additionally, the microbial uptake of 13CO had minimal to no affect on the δ13C of the cellular biomarkers, with the

  15. The pretzel sign: angiographic pattern of tortuous intra-aneurysmal blood flow in a giant serpentine aneurysm.

    LENUS (Irish Health Repository)

    Fanning, N F

    2012-02-03

    Giant serpentine aneurysms (GSAs) form a specific subgroup of giant cerebral aneurysms that have pathognomonic angiographic features. We report the angiographic findings of a GSA demonstrating a striking convoluted dynamic flow pattern, which we have called the \\'pretzel sign\\'. The aneurysm was successfully treated by permanent occlusion of the parent vessel using a detachable balloon. GSAs should be identified prior to treatment in view of their particular management requirements.

  16. Aggregates from mineral wastes

    Directory of Open Access Journals (Sweden)

    Baic Ireneusz

    2016-01-01

    Full Text Available The problem concerning the growing demand for natural aggregates and the need to limit costs, including transportation from remote deposits, cause the increase in growth of interest in aggregates from mineral wastes as well as in technologies of their production and recovery. The paper presents the issue related to the group of aggregates other than natural. A common name is proposed for such material: “alternative aggregates”. The name seems to be fully justified due to adequacy of this term because of this raw materials origin and role, in comparison to the meaning of natural aggregates based on gravel and sand as well as crushed stones. The paper presents characteristics of the market and basic application of aggregates produced from mineral wastes, generated in the mining, power and metallurgical industries as well as material from demolished objects.

  17. Economical characteristics of base types of minerals. 1. Metallic minerals

    International Nuclear Information System (INIS)

    Khasanov, A.Kh.

    1990-01-01

    Metallic minerals is raw materials base of black and colour metallurgy. In this article of book author describes the group of black metals (iron, manganese, chromium), group of tempers (titanium, vanadium, nickel, cobalt, molybdenum, tungsten), colour metals (copper, lead, zinc, aluminium, tin, mercury, antimony, bismuth) and etc.

  18. Lung Cancer in uranium miners

    International Nuclear Information System (INIS)

    Zhou Chundi; Fan Jixiong; Wang Liuhu; Huang Yiehan; Nie Guanghua

    1987-01-01

    This paper analyese the clinical data of 39 uranium miners with lung cancer and of 20 patients with lung cancer who have not been exposed to uranium as control. The age of uranium miners with lung cancer was 36∼61 with an average of 48.8, nine years earlier than that of the control group (57.3). In the uranium miner patients the right lung was more susceptible to cancer than the left, the ratio being 2.5:1. However, in the control group the right lung had an equal incidence of cancer as the left lung. The relative frequency of small cell anaplastic carcinoma in uranium miner was higher than that in the control group. In the miner patients the mean occupation history was 11.1 ± 5.2 years; the exposure dose to radon and its daughters in 50% patients was 0.504J(120 WLM). The etiologic factor of lung cancer in uranium miners is strongly attributed, in addition to smoking, to the exposure to radon and its daughters in uranium mines

  19. Glycine Polymerization on Oxide Minerals

    Science.gov (United States)

    Kitadai, Norio; Oonishi, Hiroyuki; Umemoto, Koichiro; Usui, Tomohiro; Fukushi, Keisuke; Nakashima, Satoru

    2017-06-01

    It has long been suggested that mineral surfaces played an important role in peptide bond formation on the primitive Earth. However, it remains unclear which mineral species was key to the prebiotic processes. This is because great discrepancies exist among the reported catalytic efficiencies of minerals for amino acid polymerizations, owing to mutually different experimental conditions. This study examined polymerization of glycine (Gly) on nine oxide minerals (amorphous silica, quartz, α-alumina and γ-alumina, anatase, rutile, hematite, magnetite, and forsterite) using identical preparation, heating, and analytical procedures. Results showed that a rutile surface is the most effective site for Gly polymerization in terms of both amounts and lengths of Gly polymers synthesized. The catalytic efficiency decreased as rutile > anatase > γ-alumina > forsterite > α- alumina > magnetite > hematite > quartz > amorphous silica. Based on reported molecular-level information for adsorption of Gly on these minerals, polymerization activation was inferred to have arisen from deprotonation of the NH3 + group of adsorbed Gly to the nucleophilic NH2 group, and from withdrawal of electron density from the carboxyl carbon to the surface metal ions. The orientation of adsorbed Gly on minerals is also a factor influencing the Gly reactivity. The examination of Gly-mineral interactions under identical experimental conditions has enabled the direct comparison of various minerals' catalytic efficiencies and has made discussion of polymerization mechanisms and their relative influences possible Further systematic investigations using the approach reported herein (which are expected to be fruitful) combined with future microscopic surface analyses will elucidate the role of minerals in the process of abiotic peptide bond formation.

  20. Glycine Polymerization on Oxide Minerals.

    Science.gov (United States)

    Kitadai, Norio; Oonishi, Hiroyuki; Umemoto, Koichiro; Usui, Tomohiro; Fukushi, Keisuke; Nakashima, Satoru

    2017-06-01

    It has long been suggested that mineral surfaces played an important role in peptide bond formation on the primitive Earth. However, it remains unclear which mineral species was key to the prebiotic processes. This is because great discrepancies exist among the reported catalytic efficiencies of minerals for amino acid polymerizations, owing to mutually different experimental conditions. This study examined polymerization of glycine (Gly) on nine oxide minerals (amorphous silica, quartz, α-alumina and γ-alumina, anatase, rutile, hematite, magnetite, and forsterite) using identical preparation, heating, and analytical procedures. Results showed that a rutile surface is the most effective site for Gly polymerization in terms of both amounts and lengths of Gly polymers synthesized. The catalytic efficiency decreased as rutile > anatase > γ-alumina > forsterite > α- alumina > magnetite > hematite > quartz > amorphous silica. Based on reported molecular-level information for adsorption of Gly on these minerals, polymerization activation was inferred to have arisen from deprotonation of the NH 3 + group of adsorbed Gly to the nucleophilic NH 2 group, and from withdrawal of electron density from the carboxyl carbon to the surface metal ions. The orientation of adsorbed Gly on minerals is also a factor influencing the Gly reactivity. The examination of Gly-mineral interactions under identical experimental conditions has enabled the direct comparison of various minerals' catalytic efficiencies and has made discussion of polymerization mechanisms and their relative influences possible Further systematic investigations using the approach reported herein (which are expected to be fruitful) combined with future microscopic surface analyses will elucidate the role of minerals in the process of abiotic peptide bond formation.

  1. Fault rocks and uranium mineralization

    International Nuclear Information System (INIS)

    Tong Hangshou.

    1991-01-01

    The types of fault rocks, microstructural characteristics of fault tectonite and their relationship with uranium mineralization in the uranium-productive granite area are discussed. According to the synthetic analysis on nature of stress, extent of crack and microstructural characteristics of fault rocks, they can be classified into five groups and sixteen subgroups. The author especially emphasizes the control of cataclasite group and fault breccia group over uranium mineralization in the uranium-productive granite area. It is considered that more effective study should be made on the macrostructure and microstructure of fault rocks. It is of an important practical significance in uranium exploration

  2. Recovering byproduct heavy minerals from sand and gravel, placer gold, and industrial mineral operations

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, J.M.; Martinez, G.M.; Wong, M.M.

    1979-01-01

    The Bureau of Mines, as part of an effort to maximize minerals and metals recovery from domestic resources, has investigated the feasibility of recovering heavy minerals as byproducts from sand and gravel, placer gold, and industrial mineral operations in northern California. Sand samples from about 50 locations were treated by gravity separation to yield heavy-mineral cocentrates (black sands). Mineral compositions of the concentrates were determined by chemical analysis and mineralogical examination. Individual zircon, ilmenite, magnetite, platinum-group metals, thoria, and silica products were prepared from heavy-mineral concentrates by selective separation using low- and high-intensity magnetic, high-tension, and flotation equipment.

  3. Minerals Yearbook, volume I, Metals and Minerals

    Science.gov (United States)

    ,

    2018-01-01

    The U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows:Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Chapters on survey methods, summary statistics for domestic nonfuel minerals, and trends in mining and quarrying in the metals and industrial mineral industries in the United States are also included.Volume II, Area Reports: Domestic, contains a chapter on the mineral industry of each of the 50 States and Puerto Rico and the Administered Islands. This volume also has chapters on survey methods and summary statistics of domestic nonfuel minerals.Volume III, Area Reports: International, is published as four separate reports. These regional reports contain the latest available minerals data on more than 180 foreign countries and discuss the importance of minerals to the economies of these nations and the United States. Each report begins with an overview of the region’s mineral industries during the year. It continues with individual country chapters that examine the mining, refining, processing, and use of minerals in each country of the region and how each country’s mineral industry relates to U.S. industry. Most chapters include production tables and industry structure tables, information about Government policies and programs that affect the country’s mineral industry, and an outlook section.The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the Minerals Yearbook are welcomed.

  4. Laboratory of minerals purification

    International Nuclear Information System (INIS)

    2002-01-01

    The laboratory of minerals purification was organized in 1962 where with application of modern physical and chemical methods were investigated the mechanism of flotation reagents interaction with minerals' surface, was elaborated technologies on rising complexity of using of republic's minerals

  5. Mineral resource of the month: vermiculite

    Science.gov (United States)

    Tanner, Arnold O.

    2014-01-01

    Vermiculite comprises a group of hydrated, laminar magnesium-aluminum-iron silicate minerals resembling mica. They are secondary minerals, typically altered biotite, iron-rich phlogopite or other micas or clay-like minerals that are themselves sometimes alteration products of amphibole, chlorite, olivine and pyroxene. Vermiculite deposits are associated with volcanic ultramafic rocks rich in magnesium silicate minerals, and flakes of the mineral range in color from black to shades of brown and yellow. The crystal structure of vermiculite contains water molecules, a property that is critical to its processing for common uses.

  6. South Africa's mineral industry

    International Nuclear Information System (INIS)

    1985-06-01

    The main aim of the Minerals Bureau in presenting this annual review is to provide an up-to-date reference document on the current state of the mineral industry in South Africa. This includes a brief look at the production, trade, economy, resources and deposits of precious metals and minerals, energy minerals, metallic minerals, and non-metallic minerals. One article discusses the production, trade, export, deposits and economy of uranium

  7. Platinum-group elements, S, Se and Cu in highly depleted abyssal peridotites from the Mid-Atlantic Ocean Ridge (ODP Hole 1274A): Influence of hydrothermal and magmatic processes

    Science.gov (United States)

    Marchesi, Claudio; Garrido, Carlos J.; Harvey, Jason; González-Jiménez, José María; Hidas, Károly; Lorand, Jean-Pierre; Gervilla, Fernando

    2013-11-01

    Highly depleted harzburgites and dunites were recovered from ODP Hole 1274A, near the intersection between the Mid-Atlantic Ocean Ridge and the 15°20'N Fracture Zone. In addition to high degrees of partial melting, these peridotites underwent multiple episodes of melt-rock reaction and intense serpentinization and seawater alteration close to the seafloor. Low concentrations of Se, Cu and platinum-group elements (PGE) in harzburgites drilled at around 35-85 m below seafloor are consistent with the consumption of mantle sulfides after high degrees (>15-20 %) of partial melting and redistribution of chalcophile and siderophile elements into PGE-rich residual microphases. Higher concentrations of Cu, Se, Ru, Rh and Pd in harzburgites from the uppermost and lowest cores testify to late reaction with a sulfide melt. Dunites were formed by percolation of silica- and sulfur-undersaturated melts into low-Se harzburgites. Platinum-group and chalcophile elements were not mobilized during dunite formation and mostly preserve the signature of precursor harzburgites, except for higher Ru and lower Pt contents caused by precipitation and removal of platinum-group minerals. During serpentinization at low temperature (desulfurization to S-poor sulfides (mainly heazlewoodite) and awaruite. Contrary to Se and Cu, sulfur does not record the magmatic evolution of peridotites but was mostly added in hydrothermal sulfides and sulfate from seawater. Platinum-group elements were unaffected by post-magmatic low-temperature processes, except Pt and Pd that may have been slightly remobilized during oxidative seawater alteration.

  8. Miscellaneous Industrial Mineral Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes miscellaneous industrial minerals operations in the United States. The data represent commodities covered by the Minerals Information Team...

  9. A nonlinear analysis of the terahertz serpentine waveguide traveling-wave amplifier

    International Nuclear Information System (INIS)

    Li, Ke; Cao, Miaomiao; Liu, Wenxin; Wang, Yong

    2015-01-01

    A nonlinear model for the numerical simulation of terahertz serpentine waveguide traveling-wave tube (SW-TWT) is described. In this model, the electromagnetic wave transmission in the SW is represented as an infinite set of space harmonics to interact with an electron beam. Analytical expressions for axial electric fields in axisymmetric interaction gaps of SW-TWTs are derived and compared with the results from CST simulation. The continuous beam is treated as discrete macro-particles with different initial phases. The beam-tunnel field equations, space-charge field equations, and motion equations are combined to solve the beam-wave interaction. The influence of backward wave and relativistic effect is also considered in the series of equations. The nonlinear model is used to design a 340 GHz SW-TWT. Several favorable comparisons of model predictions with results from a 3-D Particle-in-cell simulation code CHIPIC are presented, in which the output power versus beam voltage and interaction periods are illustrated. The relative error of the predicted output power is less than 15% in the 3 dB bandwidth and the relative error of the saturated length is less than 8%.The results show that the 1-D nonlinear analysis model is appropriate to solve the terahertz SW-TWT operation characteristics

  10. Radiographic features and endovascular treatment of giant serpentine aneurysms (report of 4 cases)

    International Nuclear Information System (INIS)

    Wang Anshun

    2000-01-01

    Objective: To describe the typical CT, MRI and DSA features of intracranial giant serpentine aneurysm (GSA) and discuss the efficacy of it is the endovascular treatment. Methods: Retrograde study of 4 cases of GSA admitted and treated at the center of the present study over the last 2 years was conducted. The literature before June 1988 was reviewed. Results: The findings of CT and MRI scans of GSA resembled those of intracranial neoplasms. Cerebral angiography remained the golden diagnostic criteria for GSA. Two of cases in the present study were treated with detachable balloon occlusion of the parent artery and pre-occlusion EC-IC bypass because of insufficient cross-filling through the Willis circle found on the cross-filling symmetry test. The symptoms and signs of the two patients disappeared on 1-2 year follow-up and follow-up CT study showed no obvious change in aneurysmal size. Conclusion: The GSA is different from the intracranial giant secular or fusiform aneurysms because it has distinctive features on CT, MRI and DSA studies. GSA constitutes a subgroup of the intracranial giant aneurysms. The natural history of GSA is poor so it is necessary to give GSA aggressive management. The endovascular occlusion of the parent artery with functional EC-IC bypass is safe and effective

  11. Kinetics of Grinding of Secondary Serpentine Raw Material at Cascade Operating Mode

    Directory of Open Access Journals (Sweden)

    Marek Matik

    2004-12-01

    Full Text Available The paper deals with the grinding of secondary serpentine material from the Dobšiná´s heap in a ball ceramic mill. The raw material was pre-sieved to prepare fraction of +250 –1,000 µm that was fed to the mill. During batch experiment an amount of oversize on the screen with a mesh size of 200 µm was observed as a function of time. Two speed modes were tested. Firstly, it was the mode designed by mill producer implicit from the structure of milling stand equipped by electromotor, friction gear onto driving shaft with given diameter. The speed of this original alignment attains 40 rmp. Secondly, it was cascade speed mode according to the Haase´s equation, namely 53 rmp, achieved by enlargement of driving shaft diameter. As to winning of required final product 90 % –200 µm, increased speed resulted in the shortening of grinding time from 17.5 to15.7 hour.

  12. Early Archean serpentine mud volcanoes at Isua, Greenland, as a niche for early life.

    Science.gov (United States)

    Pons, Marie-Laure; Quitté, Ghylaine; Fujii, Toshiyuki; Rosing, Minik T; Reynard, Bruno; Moynier, Frederic; Douchet, Chantal; Albarède, Francis

    2011-10-25

    The Isua Supracrustal Belt, Greenland, of Early Archean age (3.81-3.70 Ga) represents the oldest crustal segment on Earth. Its complex lithology comprises an ophiolite-like unit and volcanic rocks reminiscent of boninites, which tie Isua supracrustals to an island arc environment. We here present zinc (Zn) isotope compositions measured on serpentinites and other rocks from the Isua supracrustal sequence and on serpentinites from modern ophiolites, midocean ridges, and the Mariana forearc. In stark contrast to modern midocean ridge and ophiolite serpentinites, Zn in Isua and Mariana serpentinites is markedly depleted in heavy isotopes with respect to the igneous average. Based on recent results of Zn isotope fractionation between coexisting species in solution, the Isua serpentinites were permeated by carbonate-rich, high-pH hydrothermal solutions at medium temperature (100-300 °C). Zinc isotopes therefore stand out as a pH meter for fossil hydrothermal solutions. The geochemical features of the Isua fluids resemble the interstitial fluids sampled in the mud volcano serpentinites of the Mariana forearc. The reduced character and the high pH inferred for these fluids make Archean serpentine mud volcanoes a particularly favorable setting for the early stabilization of amino acids.

  13. One-carbon (bio ?) Geochemistry in Subsurface Waters of the Serpentinizing Coast Range Ophiolite

    Science.gov (United States)

    Hoehler, Tori M.; Mccollom, Tom; Schrenk, Matt; Cardace, Dawn

    2011-01-01

    Serpentinization - the aqueous alteration of ultramafic rocks - typically imparts a highly reducing and alkaline character to the reacting fluids. In turn, these can influence the speciation and potential for metabolism of one-carbon compounds in the system. We examined the aqueous geochemistry and assessed the biological potential of one-carbon compounds in the subsurface of the McLaughlin Natural Reserve (Coast Range Ophiolite, California, USA). Fluids from wells sunk at depths of 25-90 meters have pH values ranging from 9.7 to 11.5 and dissolved inorganic carbon (DIC concentrations) generally below 60 micromolar. Methane is present at concentrations up to 1.3 millimolar (approximately one-atmosphere saturation), and hydrogen concentrations are below 15 nanomolar, suggesting active consumption of H2 and production of CH4. However, methane production from CO2 is thermodynamically unfavorable under these conditions. Additionally, the speciation of DIC predominantly into carbonate at these high pH values creates a problem of carbon availability for any organisms that require CO2 (or bicarbonate) for catabolism or anabolism. A potential alternative is carbon monoxide, which is present in these waters at concentrations 2000-fold higher than equilibrium with atmospheric CO. CO is utilized in a variety of metabolisms, including methanogenesis, and bioavailability is not adversely affected by pH-dependent speciation (as for DIC). Methanogenesis from CO under in situ conditions is thermodynamically favorable and would satisfy biological energy requirements with respect to both Gibbs Energy yield and power.

  14. High-quality GaN epitaxially grown on Si substrate with serpentine channels

    Science.gov (United States)

    Wei, Tiantian; Zong, Hua; Jiang, Shengxiang; Yang, Yue; Liao, Hui; Xie, Yahong; Wang, Wenjie; Li, Junze; Tang, Jun; Hu, Xiaodong

    2018-06-01

    A novel serpentine-channeled mask was introduced to Si substrate for low-dislocation GaN epitaxial growth and the fully coalesced GaN film on the masked Si substrate was achieved for the first time. Compared with the epitaxial lateral overgrowth (ELOG) growth method, this innovative mask only requires one-step epitaxial growth of GaN which has only one high-dislocation region per mask opening. This new growth method can effectively reduce dislocation density, thus improving the quality of GaN significantly. High-quality GaN with low dislocation density ∼2.4 × 107 cm-2 was obtained, which accounted for about eighty percent of the GaN film in area. This innovative technique is promising for the growth of high-quality GaN templates and the subsequent fabrication of high-performance GaN-based devices like transistors, laser diodes (LDs), and light-emitting diodes (LEDs) on Si substrate.

  15. Oxygen Extraction from Minerals

    Science.gov (United States)

    Muscatello, Tony

    2017-01-01

    Oxygen, whether used as part of rocket bipropellant or for astronaut life support, is a key consumable for space exploration and commercialization. In Situ Resource Utilization (ISRU) has been proposed many times as a method for making space exploration more cost effective and sustainable. On planetary and asteroid surfaces the presence of minerals in the regolith that contain oxygen is very common, making them a potential oxygen resource. The majority of research and development for oxygen extraction from minerals has been for lunar regolith although this work would generally be applicable to regolith at other locations in space. This presentation will briefly survey the major methods investigated for oxygen extraction from regolith with a focus on the current status of those methods and possible future development pathways. The major oxygen production methods are (1) extraction from lunar ilmenite (FeTiO3) with either hydrogen or carbon monoxide, (2) carbothermal reduction of iron oxides and silicates with methane, and (3) molten regolith electrolysis (MRE) of silicates. Methods (1) and (2) have also been investigated in a two-step process using CO reduction and carbon deposition followed by carbothermal reduction. All three processes have byproducts that could also be used as resources. Hydrogen or carbon monoxide reduction produce iron metal in small amounts that could potentially be used as construction material. Carbothermal reduction also makes iron metal along with silicon metal and a glass with possible applications. MRE produces iron, silicon, aluminum, titanium, and glass, with higher silicon yields than carbothermal reduction. On Mars and possibly on some moons and asteroids, water is present in the form of mineral hydrates, hydroxyl (-OH) groups on minerals, andor water adsorbed on mineral surfaces. Heating of the minerals can liberate the water which can be electrolyzed to provide a source of oxygen as well. The chemistry of these processes, some key

  16. Minerals from Macedonia: XV. Sivec mineral assemble

    International Nuclear Information System (INIS)

    Boev, Blazho; Jovanovski, Gligor; Makreski, Petre; Bermanec, Vladimir

    2005-01-01

    The paper presents investigations carried out on the collected minerals from the Sivec deposit. It is situated in the vicinity of the town of Prilep, representing a rare occurrence of sugary white dolomite marbles. The application of suitable methods of exploitation of decorative-dimension stones makes possible to obtain large amounts of commercial blocks well known in the world. Despite the existence of dolomite marbles, a series of exotic minerals are typical in Sivec mineralization. Among them, the most significant are: calcite, fluorite, rutile, phlogopite, corundum, diaspore, almandine, kosmatite (clintonite or margarite), clinochlore, muscovite, quartz, pyrite, tourmaline and zoisite. An attempt to identify ten collected minerals using the FT IR spectroscopy is performed. The identification of the minerals was based on the comparison of the infrared spectra of our specimens with the corresponding literature data for the mineral species originating all over the world. The coloured pictures of all studied silicate minerals are presented as well. (Author)

  17. ATOMIC-LEVEL IMAGING OF CO2 DISPOSAL AS A CARBONATE MINERAL: OPTIMIZING REACTION PROCESS DESIGN; A

    International Nuclear Information System (INIS)

    M.J. McKelvy; R. Sharma; A.V.G. Chizmeshya; H. Bearat; R.W. Carpenter

    2001-01-01

    Fossil fuels, especially coal, can support the energy demands of the world for centuries to come, if the environmental problems associated with CO(sub 2) emissions can be overcome. Permanent and safe methods for CO(sub 2) capture and disposal/storage need to be developed. Mineralization of stationary-source CO(sub 2) emissions as carbonates can provide such safe capture and long-term sequestration. Mg-rich lamellar-hydroxide based minerals (e.g., brucite and serpentine) offer a class of widely available, low-cost materials, with intriguing mineral carbonation potential. Carbonation of such materials inherently involves dehydroxylation, which can disrupt the material down to the atomic level. As such, controlled dehydroxylation, before and/or during carbonation, may provide an important parameter for enhancing carbonation reaction processes. Mg(OH)(sub 2) was chosen as the model material for investigating lamellar hydroxide mineral dehydroxylation/carbonation mechanisms due to (i) its structural and chemical simplicity, (ii) interest in Mg(OH)(sub 2) gas-solid carbonation as a potentially cost-effective CO(sub 2) mineral sequestration process component, and (iii) its structural and chemical similarity to other lamellar-hydroxide-based minerals (e.g., serpentine-based minerals) whose carbonation reaction processes are being explored due to their low-cost CO(sub 2) sequestration potential. Fundamental understanding of the mechanisms that govern dehydroxylation/carbonation processes is essential for minimizing the cost of any lamellar-hydroxide-based mineral carbonation sequestration process. This report covers the third year progress of this grant, as well as providing an integrated overview of the progress in years 1-3, as we have been granted a one-year no-cost extension to wrap up a few studies and publications to optimize project impact

  18. Australian mineral industry annual review for 1986

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    This volume of the Australian Mineral Industry Annual Review records the development and performance of the industry during the calendar year 1986. It reports production, consumption, treatment, trade, prices, new developments, exploration, and resources for mineral commodities including fuels, and summarises equivalent developments abroad. Part 1, 'General Review', after briefly surveying the world mineral industry, summarises developments in the Australian mineral industry as a whole. Part 2, 'Commodity Review', covers individual mineral commodities and commodity groups including brown coal, black coal and peat. Part 3, 'Mining Census', tabulates statistics extracted from the Mining Census, together with some mineral processing statistics from the Manufacturing Census. Part 4, tabulates quantity and value data on mineral output provided by the State departments of mines and their equivalents. The commodity review of black coal has been abstracted separately.

  19. Gênese de solos derivados de rochas ultramáficas serpentinizadas no sudoeste de Minas Gerais Genesis of soils formed from ultramafic serpentinized rocks in southwestern Minas Gerais (Brazil

    Directory of Open Access Journals (Sweden)

    Pablo Vidal-Torrado

    2006-06-01

    presença de minerais primários de fácil decomposição até mesmo na fração argila, com destaque para o talco, clorita trioctaedral e ocorrência limitada de tremolita, sendo esta última abundante na fração silte. Óxidos de Fe, caulinita e os interestratificados de clorita-esmectita e de clorita-vermiculita completam a assembléia mineralógica. A tendência de evolução é para B textural ou para B nítico com mineralogia 1:1 e alto conteúdo de óxidos de Fe. Nas fases iniciais de alteração, os alteromorfos já apresentam composição química similar aos agregados do solo, com forte perda de Mg, Ca e Si e acúmulo relativo de Al e Fe. Nas três situações estudadas, ocorreu um rejuvenescimento superficial por erosão diferencial, que acumulou material grosseiro e removeu os finos, contribuindo para o incremento da relação textural.Soils formed from serpentinized rocks or serpentinites constitute a special group of soils on the earth surface. These rocks present ultramafic characteristics, with more than 70 % mafic minerals (iron and magnesium oxides. The mineralogy of serpentinites is poor in silica and aluminum and very rich in Mg. Only few studies have looked into the morphology, mineralogy, genesis and classification of soils developed on this type of parent material. In the humid-tropical climate of southwestern Minas Gerais state, three representative soil profiles were taken from the Morro do Ferro, in the Greenstone Belt area, on young geomorphic surfaces. They were characterized by macro and micromorphological descriptions, particle size distribution and chemical analysis, and X ray mineralogical analysis of the clay and sand fractions. The geochemical alterations in the soil horizons were characterized by EDRX microanalyses of soil thin sections. The soils were classified as Haplic Phaeozern Eutric Regosol and chromic Cambisol. Although these soils are developed in a climate that favors quick weathering, from a morphological and mineralogical

  20. Petrography and mineral chemistry of wehrlites in contact zone of gabbro intrusions and mantle peridotites of the Naein ophiolite

    Directory of Open Access Journals (Sweden)

    Farhad Ghaseminejad

    2014-10-01

    Full Text Available Introduction Geological background Ophiolites have played a major role in our understanding of Earth’s processes ranging from seafloor spreading, melt evolution and magma transport in oceanic spreading centers, and hydrothermal alteration and mineralization of oceanic crust to collision tectonics, mountain building processes, and orogeny. They provide the essential structural, petrological, geochemical, and geochronological evidence to document the evolutionary history of ancient continental margins and ocean basin. Ophiolites include a peridotitic mantle sequence, generally characterized by high-temperature plastic deformation and residual chemistry, and a comagmatic crustal sequence (gabbros, diabase dikes, and submarine basalts, weakly or not deformed. According to this interpretation, ophiolites were allochthonous with respect to their country rocks. They were assembled during a primary accretion stage at an oceanic spreading center, and later tectonically emplaced on a continental margin or island arc (Dilek, 2003. The indigenous dikes of pyroxenites and gabbros that were injected into a melting peridotite, or intrusive dikes of pyroxenite and gabbro that injected when the peridotite was fresh and well below its solidus, are discussed in different ophiolite papers. Pyroxenite formation and contact of gabbro and mantle peridotite are discussed in different articles (Dilek, 2003. When a gabbro intrude a fresh mantle peridotite could not significantly react with it, but if intrusion occurs during the serpentinization, the gabbro will change to rodingite. Geological setting The Naein ophiolitic melanges comprise the following rock units: mantle peridotites (harzburgite, lherzolite, dunite, with associated chromitite, gabbro, pyroxenite, sheeted and swarm dikes, massive basalts, pillow lava, plagiogranite, radiolarian chert, glaubotruncana limestone, rodingite, listvenite, and metamorphic rocks (foliated amphibolitic dike, amphibolite, skarn

  1. A review and comparison of fracture mineral investigations and their application to radioactive waste disposal

    International Nuclear Information System (INIS)

    Blyth, A.R.; Frape, S.K.; Tullborg, E.-L.

    2009-01-01

    A compilation and comparison of fracture mineral studies from the Canadian and Fennoscandian Shields and the French Massif Central shows many similarities indicating larger external control over fracture mineral deposition, with different rock types exerting local controls. The sites investigated represent a wide range of geological settings, and host rock types ranging from felsic intrusive and extrusives to ultramafic intrusives and volcanics that span an age range from 2.5 to 0.36 Ga. Typical fracture minerals found at Canadian Shield sites include calcite, quartz, chlorite and clays, and these do not appear to be dependant on age, erosional depth or geological environment. The Fennoscandian Shield has a much larger variety of fracture filling minerals with epidote, zeolites, prehnite, fluorite, pyrrhotite, Fe oxides, serpentine, graphite, magnesite and barite in addition to the minerals typically found at Canadian Shield sites. The major control on fracture mineral type is most likely variations in rock type, and fluid chemistry and temperature. The C and O isotopic range of calcite is very similar among sites. Late-stage hydrothermal calcite, with strongly depleted δ 18 O values, is common at many sites. All of the sites have calcite with δ 18 O isotopic values in the range of -5 to -20 per mille PDB, indicative of formation from meteoric water or basinal brines that have undergone varying degrees of water/rock interaction. One Canadian and a few Swedish sites have calcite in the shallower portion of the rock that shows isotopic evidence of dissolution and re-precipitation in equilibrium with the present-day waters. There are some striking similarities in fluid inclusion data among sites. Most sites have an elevated temperature (100-300 deg. C), low salinity group of fluid inclusions within the NaCl-H 2 O system, and a lower temperature (50-150 deg. C), higher salinity group of fluid inclusions within the NaCl-CaCl 2 -H 2 O system. Fluid inclusion density

  2. Experimental investigation of serpentine-talc-brucite associations not determined in the nature

    International Nuclear Information System (INIS)

    Abdullayev, Z.B.

    2008-01-01

    The hydrothermal transformation of serpentinites of different mineral composition in the conditions of different valees of temperature and pressure is described. It was determined that mineral composition is independent, serpenites are stable within 520 degrees Celsius temperature and 35 kbar of pressure. There are formed talc-phorsterite association and then phorsterite-enstatite at high temperature up to 600 degrees Celsius and the pressure up to 50 kbar

  3. Numerical investigation of supercritical LNG convective heat transfer in a horizontal serpentine tube

    Science.gov (United States)

    Han, Chang-Liang; Ren, Jing-Jie; Dong, Wen-Ping; Bi, Ming-Shu

    2016-09-01

    The submerged combustion vaporizer (SCV) is indispensable general equipment for liquefied natural gas (LNG) receiving terminals. In this paper, numerical simulation was conducted to get insight into the flow and heat transfer characteristics of supercritical LNG on the tube-side of SCV. The SST model with enhanced wall treatment method was utilized to handle the coupled wall-to-LNG heat transfer. The thermal-physical properties of LNG under supercritical pressure were used for this study. After the validation of model and method, the effects of mass flux, outer wall temperature and inlet pressure on the heat transfer behaviors were discussed in detail. Then the non-uniformity heat transfer mechanism of supercritical LNG and effect of natural convection due to buoyancy change in the tube was discussed based on the numerical results. Moreover, different flow and heat transfer characteristics inside the bend tube sections were also analyzed. The obtained numerical results showed that the local surface heat transfer coefficient attained its peak value when the bulk LNG temperature approached the so-called pseudo-critical temperature. Higher mass flux could eliminate the heat transfer deteriorations due to the increase of turbulent diffusion. An increase of outer wall temperature had a significant influence on diminishing heat transfer ability of LNG. The maximum surface heat transfer coefficient strongly depended on inlet pressure. Bend tube sections could enhance the heat transfer due to secondary flow phenomenon. Furthermore, based on the current simulation results, a new dimensionless, semi-theoretical empirical correlation was developed for supercritical LNG convective heat transfer in a horizontal serpentine tube. The paper provided the mechanism of heat transfer for the design of high-efficiency SCV.

  4. Australian mineral industry annual review for 1984

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    This volume of the Australian Mineral Industry Annual Review records development and performance of the Australian mineral industry during the calendar year 1984. It reports production, consumption, treatment, trade, prices, new developments, exploration, and resources for mineral commodities including fuels, and summarises equivalent developments abroad. Part 1. 'general review' after briefly surveying the world mineral industry, summarises developments in the Australian mineral industry as a whole, under the headings: the industry in the national economy, prices, exploration expenditure, investment, income tax, royalties, structural data, wages and salaries, industrial disputes, and government assistance, legislation, and controls. Part 2. 'commodity review' covers individual mineral commodity groups, from abrasives to zirconium. Part 3, 'mining census', tabulates statistics extracted from the mining census, together with some mineral processing statistics from the manufacturing census. Part 4 tabulates quantity and value data on mineral output provided by state departments of mines and their equivalents. Listed in appendices are: principal mineral producers; ore buyers and mineral dealers; government mining services; analytical laboratories; state mines departments and equivalents; industry, professional and development organisations and associations, etc; summary of mineral royalties payable in the states and territories; and summary of income tax provisions and federal government levies.

  5. Early thermal history of Rhea: the role of serpentinization and liquid state convection

    Science.gov (United States)

    Czechowski, Leszek; Losiak, Anna

    2015-04-01

    Intorduction: Thermal history of Rhea from the beginning of accretion is investigated. The numerical model of convection combined with the parameterized theory is developed. Melting of the satellite's matter, gravitational differentiation and serpentinization of silicates are included. The role of the following parameters of the model is investigated: time of beginning of accretion, duration of accretion, viscosity of ice close to the melting point, activation energy in the formula for viscosity E, thermal conductivity of silicate component, ammonia content X, and energy of serpentinization. 1. Numerical model: In our calculations we use numerical model developed by Czechowski (2012) (see e.g. description in [1]). The model is based on parameterized theory of convection combined with 1-dimensional equation of the heat transfer in spherical coordinates: δT(r,t)- ρcp δt = div(k(r,T ) gradT (r,t))+ Q(r,T), where r is the radial distance (spherical coordinate), ρ is the density [kg m-3], cp [J kg1 K-1 ] is the specific heat, Q [W kg-1] is the heating rate, and k[W m-1 K-1] is the thermal conductivity. Q(r,t) includes sources and sinks of the heat. The equation is solved in time dependent region [0, R(t)]. During accretion the radius R(t) increases in time according to formula: R(t) = atfor tini tac , i.e. after the accretion (see e.g. [2]), where tinidenotes beginning of accretion and tac denotes duration of this process. If the Rayleigh number in the considered layer exceeds its critical value Racr then convection starts. It leads to effective heat transfer. The full description of convection is given by a velocity field and temperature distribution. However, we are interested in convection as a process of heat transport only. For solid state convection (SSC) heat transport can be described by dimensionless Nusselt number Nu. We use the following definition of the Nu: Nu= (True total surface heat flow)/(Total heat flow without convection). The heat transport by

  6. Out of the dark: Transitional subsurface-to-surface microbial diversity in a terrestrial serpentinizing seep (Manleluag, Pangasinan, the Philippines

    Directory of Open Access Journals (Sweden)

    Kristin eWoycheese

    2015-02-01

    Full Text Available In the Zambales ophiolite range terrestrial serpentinizing fluid seeps host diverse microbial assemblages. The fluids fall within the profile of Ca2+-OH--type waters, indicative of active serpentinization, and are low in dissolved inorganic carbon (<0.5 ppm. Influx of atmospheric carbon dioxide affects the solubility of calcium carbonate as distance from the source increases, triggering the formation of meter-scale travertine terraces. Samples were collected at the source and along the outflow channel to determine subsurface microbial community response to surface exposure. DNA was extracted and submitted for high-throughput 16S rRNA gene sequencing on the Illumina MiSeq platform. Taxonomic assignment of the sequence data indicates that 8.1% of the total sequence reads at the source of the seep affiliate with the genus Methanobacterium. Other major classes detected at the source include anaerobic taxa such as Bacteroidetes (40.7% of total sequence reads and Firmicutes (19.1% of total reads. Hydrogenophaga spp. increase in relative abundance as redox potential increases. At the carbonate terrace, 45% of sequence reads affiliate with Meiothermus spp. Taxonomic observations and geochemical data suggest that several putative metabolisms may be favorable, including hydrogen oxidation, H2-associated sulfur cycling, methanogenesis, methanotrophy, nitrogen fixation, ammonia oxidation, denitrification, nitrate respiration, methylotrophy, carbon monoxide respiration, and ferrous iron oxidation, based on capabilities of nearest known neighbors. Scanning electron microscopy and energy dispersive X-ray spectroscopy suggest that microbial activity produces chemical and physical traces in the precipitated carbonates forming downstream of the seep’s source. These data provide context for future serpentinizing seep ecosystem studies, particularly with regards to tropical biomes.

  7. Boron, lithium and methane isotope composition of hyperalkaline waters (Northern Apennines, Italy): Terrestrial serpentinization or mixing with brine?

    International Nuclear Information System (INIS)

    Boschetti, Tiziano; Etiope, Giuseppe; Pennisi, Maddalena; Romain, Millot; Toscani, Lorenzo

    2013-01-01

    Highlights: ► First data on boron and lithium isotope on waters from ophiolites are described. ► High boron and lithium isotope composition may be related to terrestrial serpentinization. ► Methane isotope data show unusual biotic signature. - Abstract: Spring waters issuing from serpentinized ultramafic rocks of the Taro-Ceno Valleys (Northern Apennine, Emilia-Romagna region, Italy) were analyzed for major element, trace element and dissolved gas concentrations and δ 11 B, δ 7 Li, δ 18 O(H 2 O), δ 2 H(H 2 O), δ 13 C(CH 4 ) and δ 2 H(CH 4 ) isotope compositions. Similar to other springs worldwide that issue from serpentinites, the chemical composition of the waters evolves with water–rock interaction from Ca-HCO 3 , through Mg-HCO 3 and ultimately to a hyperalkaline Na-(Ca)-OH composition. Most of the Ca- and Mg-HCO 3 springs have δ 11 B ranging between +16.3‰ and +23.7‰, consistent with the range of low P–T serpentinites. Very high δ 11 B in two springs from Mt. Prinzera (PR10: +39‰; PR01: +43‰) can be related to isotopic fractionation during secondary phase precipitation, as also inferred from δ 7 Li values. In contrast to typical abiogenic isotope signatures of CH 4 from serpentinized rocks, dissolved CH 4 from the Taro-Ceno hyperalkaline springs has an apparent biotic (thermogenic and/or mixed thermogenic-microbial) signature with δ 13 C(CH 4 ) ranging from −57.5‰ to −40.8‰, which is similar to that of hydrocarbons from production wells and natural seeps in adjacent hydrocarbon systems. The data suggest that CH 4 in the hyperalkaline springs investigated in this study may derive from organic matter of the sedimentary (flysch and arenaceous) formations underlying the ophiolite unit. However, small amounts of H 2 were detected in one hyperalkaline spring (PR10), but for two springs with very low CH 4 concentrations (PR01 and UM15) the δ 2 H value could not be measured, so the occurrence of some abiotic CH 4 cannot be excluded

  8. Thermo-hydraulic characteristics of serpentine tubing in the boilers of gas cooled reactors under condition of rapid and slow depressurization

    International Nuclear Information System (INIS)

    Abouhadra, D.S.; Byrne, J.E.

    2003-01-01

    In nuclear reactors of the magnox or advanced gas cooled type, serpentine tubing is used in some designs to generate steam in a once through arrangement. The calculation of accidents using two phase flow codes requires knowledge of the heat transfer behaviour of the boiler steam side. A series of experiments to study the blowdown characteristics of a typical serpentine boiler section was devised in order to validate the MARTHA section of the MACE code used by nuclear electric . The tests were carried out on the thermal hydraulics experimental research assembly (THERA) loop at manchester university. Depressurization from an initial pressure of 60 bar, with fluid subcooling of 5 k, 50 k, and 100 k was controlled by discharging the test section contents through suitably chosen orifices to produce blowdown to 10% of the initial pressure over a time scale of 30 s to 3600 s. pressures and temperatures in the serpentine were measured at average time intervals of approximately 1 s

  9. Redox flow batteries with serpentine flow fields: Distributions of electrolyte flow reactant penetration into the porous carbon electrodes and effects on performance

    Science.gov (United States)

    Ke, Xinyou; Prahl, Joseph M.; Alexander, J. Iwan D.; Savinell, Robert F.

    2018-04-01

    Redox flow batteries with flow field designs have been demonstrated to boost their capacities to deliver high current density and power density in medium and large-scale energy storage applications. Nevertheless, the fundamental mechanisms involved with improved current density in flow batteries with serpentine flow field designs have been not fully understood. Here we report a three-dimensional model of a serpentine flow field over a porous carbon electrode to examine the distributions of pressure driven electrolyte flow penetrations into the porous carbon electrodes. We also estimate the maximum current densities associated with stoichiometric availability of electrolyte reactant flow penetrations through the porous carbon electrodes. The results predict reasonably well observed experimental data without using any adjustable parameters. This fundamental work on electrolyte flow distributions of limiting reactant availability will contribute to a better understanding of limits on electrochemical performance in flow batteries with serpentine flow field designs and should be helpful to optimizing flow batteries.

  10. Surface characterization of bacterial cells relevant to the mineral industry

    NARCIS (Netherlands)

    Sharma, PK; Rao, KH

    Bacteria belonging to the Acidithiobacilli group are widely used in the mineral processing industry in bioleaching and biobeneficiation operations. Paenibacillus polymyxa has also found application in biobeneficiation studies. Microbial adhesion to mineral surface is an essential step,for both

  11. Sorption of Sr and Cs on rocks and minerals. Pt. 1

    International Nuclear Information System (INIS)

    Torstenfelt, B.; Andersson, K.; Allard, B.

    1981-09-01

    The sorption of Sr 90 and Cs 137 on some common Swedish rocks (granite, gneiss, and diabase) and eleven different major rock-forming minerals (quartz, orthoclase, apatite, fluorite, biotite, muscovite, hematite, magnetite, hornblende, calcite, and serpentine) has been studied, using a batch technique. A comparison with the retention obtained in column experiments has been made. The water phase in all experiments has been an artificial groundwater with a composition corresponding to Swedish natural deep groundwaters. The influence of parameters, such as pH (4-11), contact time (1 day-6 months), nuclide concentration (normally 10 -7 M, variations up to 0.1 M has been made), liquid to solid ratio, particle size (three fractions between 0.045 and 0.500 mm) has been studied. An attempt to predict the distribution coefficient for rocks, using known data for the rock-forming minerals gave too low values in all cases. (Auth.)

  12. Preliminary report about minerals raw materials

    International Nuclear Information System (INIS)

    Bossi, J.

    1965-01-01

    The group of experts entrusted to construct the bases to study the mineral matters has established priorities for the development of mineral resources during the next ten years: 1) aerial photography, 2) geological map, 3) mechanisms for the exploitation, 4) budget

  13. Mineral Carbonation Potential of CO2 from Natural and Industrial-based Alkalinity Sources

    Science.gov (United States)

    Wilcox, J.; Kirchofer, A.

    2014-12-01

    Mineral carbonation is a Carbon Capture and Storage (CSS) technology where gaseous CO2 is reacted with alkaline materials (such as silicate minerals and alkaline industrial wastes) and converted into stable and environmentally benign carbonate minerals (Metz et al., 2005). Here, we present a holistic, transparent life cycle assessment model of aqueous mineral carbonation built using a hybrid process model and economic input-output life cycle assessment approach. We compared the energy efficiency and the net CO2 storage potential of various mineral carbonation processes based on different feedstock material and process schemes on a consistent basis by determining the energy and material balance of each implementation (Kirchofer et al., 2011). In particular, we evaluated the net CO2 storage potential of aqueous mineral carbonation for serpentine, olivine, cement kiln dust, fly ash, and steel slag across a range of reaction conditions and process parameters. A preliminary systematic investigation of the tradeoffs inherent in mineral carbonation processes was conducted and guidelines for the optimization of the life-cycle energy efficiency are provided. The life-cycle assessment of aqueous mineral carbonation suggests that a variety of alkalinity sources and process configurations are capable of net CO2 reductions. The maximum carbonation efficiency, defined as mass percent of CO2 mitigated per CO2 input, was 83% for CKD at ambient temperature and pressure conditions. In order of decreasing efficiency, the maximum carbonation efficiencies for the other alkalinity sources investigated were: olivine, 66%; SS, 64%; FA, 36%; and serpentine, 13%. For natural alkalinity sources, availability is estimated based on U.S. production rates of a) lime (18 Mt/yr) or b) sand and gravel (760 Mt/yr) (USGS, 2011). The low estimate assumes the maximum sequestration efficiency of the alkalinity source obtained in the current work and the high estimate assumes a sequestration efficiency

  14. Construction Minerals Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes construction minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

  15. Agricultural Minerals Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes agricultural minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

  16. The Kolmården serpentine marble in Sweden, a building stone found at many levels in the society.

    Science.gov (United States)

    Wikström, Anders; Pereira, Dolores

    2013-04-01

    The Kolmården marble is a green serpentine marble of Svekofennian age (c. 1900 Ma). Serpentine is mainly secondary after diopside. The rock has been used as far back as in the 13th century. But it was mainly due to the start of the building of the Royal castles in Stockholm in the 17th century when the stone became more extensively used. The quarries were in operation until the 1970s and during the last years the production was so rationalized that one finds the stone in stairs, pavement and non structural ornaments within "common" houses all over the country. One can also find this stone in many exclusive places all over the world (e.g. the Paris Opera house, League of Nations building in Geneva, Leeds University Library, Uppsala University, Rockefeller Center, etc). The importance of this stone in international architecture, the good physical and mechanical behaviour observed in its emplacements and the possibilities for preservation of some of the quarries makes the Kolmården marble a good candidate as Global Stone Heritage Stone. The nomination will also trigger international publications on this natural stone to spread its knowledge among scientists and architects to be able to select this rock in case that some restoration on the mentioned important buildings is needed at some point.

  17. Pressure drop and flow distribution characteristics of single and parallel serpentine flow fields for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Baek, Seung Man; Kim, Charn Jung; Jeon, Dong Hyup; Nam, Jin Hyun

    2012-01-01

    This study numerically investigates pressure drop and flow distribution characteristics of serpentine flow fields (SFFs) that are designed for polymer electrolyte membrane fuel cells, which consider the Poiseuille flow with secondary pressure drop in the gas channel (GC) and the Darcy flow in the porous gas diffusion layer (GDL). The numerical results for a conventional SFF agreed well with those obtained via computational fluid dynamics simulations, thus proving the validity of the present flow network model. This model is employed to characterize various single and parallel SFFs, including multi-pass serpentine flow fields (MPSFFs). Findings reveal that under rib convection (convective flow through GDL under an interconnector rib) is an important transport process for conventional SFFs, with its intensity being significantly enhanced as GDL permeability increases. The results also indicate that under rib convection can be significantly improved by employing MPSFFs as the reactant flow field, because of the closely interlaced structure of GC regions that have different path lengths from the inlet. However, reactant flow rate through GCs proportionally decreases as under rib convection intensity increases, suggesting that proper optimization is required between the flow velocity in GCs and the under rib convection intensity in GDLs

  18. Study of temperature effect on the physical properties of ilmenite-serpentine heat resistant concrete radiation shields

    International Nuclear Information System (INIS)

    Kany, A.M.I.; EL-Fouly, M.M.; EL-Gohary, M.I.; Makatious, A.S.; Kamal, S.M.

    1990-01-01

    A series of experimental studies have been carried out to determine the change in unit weigh, compressive strength, water content and neutron macroscopic cross section of a new type of concrete shields made from egyptian ilmenite and serpentine ores when heated for long period at temperatures up to 600 degree C. Results show that the unit weight of the cure concrete has a value of 2.98 Ton/M 3 and decreases with increasing temperature, while the compressive strength reaches a maximum value of 19 Ton/M 2 at 100 degree C. The differential thermal analysis (D.T.A.) of this concrete shows three endothermic peaks at 100 degree C, 48 degree C and 740 degree C. Also, the thermogravimetry analysis (T.G.A.) shows that the cure concrete retains about 11% water content of the total sample weigh and still retains 4.5% of its initial value when heated for long period at 600 degree C. Results also show that the neutron macroscopic cross section (for neutrons of energies < 1 MeV) of the ilmenite-serpentine heat resistant concrete decreases to 18.6% of its initial value after heating to 600 degree C

  19. Mineral commodity summaries 2015

    Science.gov (United States)

    ,

    2015-01-01

    Each chapter of the 2015 edition of the U.S. Geological Survey (USGS) Mineral Commodity Summaries (MCS) includes information on events, trends, and issues for each mineral commodity as well as discussions and tabular presentations on domestic industry structure, Government programs, tariffs, 5-year salient statistics, and world production and resources. The MCS is the earliest comprehensive source of 2014 mineral production data for the world. More than 90 individual minerals and materials are covered by two-page synopses.

  20. Proton induced luminescence of minerals

    Energy Technology Data Exchange (ETDEWEB)

    Calvo del Castillo, H.; Millan, A.; Calderon, T. [Depto. Geologia y Geoquimica, Universidad Autonoma de Madrid, Ctra. Colmenar, km. 15, 28049, Madrid (Spain); Beneitez, P. [Departamento Quimica Fisica Aplicada, Universidad Autonoma de Madrid Cantoblanco, Madrid (Spain); Ruvalcaba S, J.L. [lFUNAM, Circuito de la lnvestigacion Cientifica s/n, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)

    2008-07-01

    This paper presents a summary of Ionoluminescence (IL) for several minerals commonly found in jewellery pieces and/or artefacts of historical interest. Samples including silicates and non-silicates (native elements, halide, oxide, carbonate and phosphate groups) have been excited with a 1.8 MeV proton beam, and IL spectra in the range of 200- 900 nm have been collected for each one using a fiber optic coupled spectrometer. Light emissions have been related to Cr{sup 3+}, Mn{sup 2+} and Pr{sup 3+} ions, as well as intrinsic defects in these minerals. Results show the potential of IL for impurity characterization with high detection limits, local symmetry studies, and the study of the origin of minerals. (Author)

  1. Radon risk in ore miners

    International Nuclear Information System (INIS)

    Beno, M.

    1997-01-01

    Underground workers are exposed to various clastogenic agents. One of these agents, radon, attracts attention of recent research as it causes lung cancer in the population occupationally exposed to its various concentrations especially in mine air of uranium mines or ore mines. This paper is a pilot study in which the numbers of chromosomal aberrations (CA) in lymphocytes of ore mines (Nizna Slana-iron ore, Hnusta-talc ore) located in east central Slovakia were followed and related to the lifetime underground radon exposure and to lifetime smoking. Seventy miners volunteering after an informed consent served as donors of venous blood. Twenty healthy pro-bands, age matched with the miners, which never worked underground (mostly clerks) served as donors of control blood samples. The exposure to radon and smoking has been estimated according to working-records and personal anamnesis. The findings unequivocally showed a small but statistically significant clastogenic effect of the exposure to underground environment of the mines concerned. This study has shown also a small but significant influence of smoking, which in the subgroup of miners working underground less than 1500 shifts may have acted synergically with the underground exposure. It was concluded tat: (1) Significantly higher counts of chromosomal aberrations in lymphocytes of 70 miners than in an age matched control group of 20 white-collar workers were found; (2) The higher counts of chromosomal aberrations could be ascribed to underground exposure of miners and to smoking; (3) The positive dependence of the number of chromosomal aberrations from the exposure to smoking was loose and it was expressed by significantly higher chromosomal aberrations counts in the group of miners working less than 1500 shifts underground; (4) A dependence of chromosomal aberrations counts from the exposure to radon could not be assessed. At relatively low numbers of pro-bands in subgroups it was not ruled out the confounding

  2. Silicoaluminous minerals analysis

    International Nuclear Information System (INIS)

    Puglisi, Celia; Fina, J.P.

    1987-01-01

    A group of silicoaluminous minerals of known composition have been analyzed by means of an energy dispersive electron microprobe. The analysis has been performed using a standarless semiquantitative method. The concentration was calculated using the program included in the software of the on-line computer, based on the ZAF correction. It is well known that it is difficult to analyze Si, Al and Na by this method because the absortion correction in the range of 0.9 to 2.0 KeV is not very accurate and the background substraction is also questionable. The purpose of this work is to evaluate the errors involved in these measurements and the best operation conditions. (Author) [es

  3. Fissure minerals, literature review

    International Nuclear Information System (INIS)

    Larsson, S.Aa.

    1980-01-01

    This paper is a review of methods used for direct and indirect dating of tectonic events. Isotope geochemistry including stable isotopes as well as fission track- dating, fluid inclusion and thermoluminescens techniques have been considered. It has been concluded that an investigation of tectonic (and thermal) events should start with a detailed study of the mineral phases grown in seald fissures as well as minerals from fissure walls. This study should include phase identification, textures as well as mineral chemistry. The information from this study is fundamental for the decision of further investigations. Mineral chemistry including isotopes and fluid inclusion studies will give an essential knowledge about crystallization conditions for fissure minerals concerned. Direct dating using fission tracks as well as radioactive isotopes could be useful for some minerals. Application of thermoluminescens dating on fissure minerals is doubtful. (Auth.)

  4. Influence of dunite mineral additive on strength of cement

    Science.gov (United States)

    Vasilyeva, A. A.; Moskvitina, L. V.; Moskvitin, S. G.; Lebedev, M. P.; Fedorova, G. D.

    2017-12-01

    The work studies the applicability of dunite rocks from Inagli massif (South Yakutia) for the production of mixed (composite) cement. The paper reviews the implementation of dunite for manufacturing materials and products. The chemical and mineral compositions of Inagli massif dunite rocks are presented, which relegate the rocks to magnesia-silicate rocks of low-quality in terms of its application as refractory feedstock due to appreciable serpentinization of dunite. The work presents the results of dunite study in terms of its applicability as an additive to Portland cement. The authors have established that dunite does not feature hydraulicity and can be used as a filling additive to Portland cement in the amount of up to 40%. It was unveiled that the mixed grinding of Portland cement and dunite sand with specific surface area of 5500 cm2/g yields the cement that complies with GOST 31108-2016 for CEM II and CEM V normal-cured cements with strength grades of 32.5 and 42.5. The work demonstrates the benefits of the studies of dunite as a filling additive for producing both Portland cement with mineral component and composite (mixed) cement.

  5. Mineral Facilities of Latin America and Canada

    Science.gov (United States)

    Bernstein, Rachel; Eros, Mike; Quintana-Velazquez, Meliany

    2006-01-01

    This data set consists of records for over 900 mineral facilities in Latin America and Canada. The mineral facilities include mines, plants, smelters, or refineries of aluminum, cement, coal, copper, diamond, gold, iron and steel, nickel, platinum-group metals, salt, and silver, among others. Records include attributes such as commodity, country, location, company name, facility type and capacity if applicable, and generalized coordinates. The data were compiled from multiple sources, including the 2003 and 2004 USGS Minerals Yearbooks (Latin America and Candada volume), data to be published in the 2005 Minerals Yearbook Latin America and Canada Volume, minerals statistics and information from the USGS minerals information Web site (minerals.usgs.gov/minerals), and data collected by USGS minerals information country specialists. Data reflect the most recent published table of industry structure for each country. Other sources include statistical publications of individual countries, annual reports and press releases of operating companies,and trade journals. Due to the sensitivity of some energy commodity data, the quality of these data should be evaluated on a country-by-country basis. Additional information and explanation is available from the country specialists.

  6. Genesis of high-zinc chromite and associated cobalt-mineralized blackwall in the Sykesville District, Maryland piedmont

    Energy Technology Data Exchange (ETDEWEB)

    Wylie, A.G.; Candela, P.A.; Burke, T.M.

    1985-01-01

    Zone, Zn-bearing chromites occur in a serpentinized ultramafite (UM), pelitic schists, the associated blackwall, and a banded Fe oxide-quartz rock (BIR). The spinels are associated with Fe-Cu-Co mineralization in the Sykesville District of the Maryland Piedmont. Within most grains, three main zones can be distinguished based on optical properties and chemistry. The marked discontinuity between the central core and the middle zone (ferrit-chromite (FC)) and the anhedral form of the core suggest that the FC developed by the irreversible dissolution of the core and reprecipitation of FC as a mantle. The outer magnetite zone was added during the latter stages of serpentinization as chemical communication with the original spinel core ceased. The highest Zn contents occur in the spinel cores near the boundary with the FC. ZnO contents of up to 19 wt.% have been measured. To the authors knowledge, these are the highest reported concentrations of Zn in chromite. The Zn/Mg ratio in the spinel cores correlates closely with the host rock mineralogy such that /mu//sub ZnMg/ decreases monotonically from the pelite into the UM. The occurrence of chromite in all rock units and the strong field association between the UM and the BIR suggest that UM material was present on the seafloor. Based on chemical and textural evidence, the authors postulate that Zn was introduced during the earliest stages of the hydrothermal processes accompanying serpentinization and mineralization in a subaqueous environment. Cu and Zn were probably supplied by a seafloor hydrothermal system, and the BIR and Co were produced alteration of the UM unit.

  7. Fluid and element transfer at the slab-mantle interface: insights from the serpentinized Livingstone Fault, New Zealand

    Science.gov (United States)

    Smith, S. A. F.; Scott, J.; Tarling, M.; Tulley, C. J.; le Roux, P. J.

    2017-12-01

    At the slab-mantle interface in subduction zones, hydrous fluids released by dehydration reactions are fluxed upwards into the fore-arc mantle corner. The extent to which these fluids can move across the plate interface shear zone has significant implications for understanding the composition of the mantle wedge and the origin of episodic tremor and slow slip. The >1000 km long Livingstone Fault in New Zealand provides a superbly exposed analogue (both in terms of scale and the rock types involved) for the serpentinite shear zone likely to be present along the slab-mantle interface. The Livingstone Fault is a sheared serpentinite mélange up to several hundreds of meters wide that separates greenschist-facies quartzofeldspathic metasediments (e.g. analogue for slab sediments) from variably-serpentinized harzburgitic peridotite (e.g. analogue for mantle wedge). To track element mobility and paleo-fluid flow across the shear zone, Sr and Nd isotopes were measured in five transects across the metasediments, mélange and serpentinized peridotites. Results show that the mélange and serpentinized peridotites (originally with Sr and Nd similar to Permian MORB) were progressively overprinted with the isotopic composition of the metasediments at distances of up to c. 400 m from the mélange-metasediment contact. Mass balance calculations require that many elements were mobile across the mélange shear zone, but permeability modeling indicates that diffusive transfer of such elements is unrealistically slow. Instead, it appears that fluid and element percolation in to and across the mélange was aided by episodic over-pressuring and fracturing, as indicated by the widespread presence of tremolite-bearing breccias and veins that mutually cross-cut the serpentinite mélange fabrics. Overall, the field and isotopic results indicate that fluid and element redistribution within major serpentinite-bearing shear zones is strongly aided by fracturing and brecciation that are

  8. 43 CFR 19.8 - Prospecting, mineral locations, mineral patents, and mineral leasing within National Forest...

    Science.gov (United States)

    2010-10-01

    ... patents, and mineral leasing within National Forest Wilderness. 19.8 Section 19.8 Public Lands: Interior... § 19.8 Prospecting, mineral locations, mineral patents, and mineral leasing within National Forest... locations, mineral patents, and mineral leasing within National Forest Wilderness are contained in parts...

  9. Radioactive mineral deposits

    Energy Technology Data Exchange (ETDEWEB)

    1948-01-01

    This publication was designed as a guide for uranium and thorium prospectors in Australia. Physical properties, such as color, streak, luster, hardness, fracture, and specific gravity of the uranium and thorium-bearing minerals are summarized and the various methods suitable for detecting radioactivity in minerals are described. Two colored plates show samples of pitchblende (uraninite), autunite, carnotite, monazite, and others of the most important minerals sources of uranium and thorium.

  10. Cancer of lung in miners

    International Nuclear Information System (INIS)

    Kolenic, J.; Jurgova, T.; Volckova, A.; Zimacek, J.

    1995-01-01

    In the period of 1983-1994 was registered at Clinic of occupational diseases 87 cases of professional cancer of lung. Mostly /85/ of cases was related to miners, by whom act as risk factor alpha ionisation from radon. Average age group was 60.2 y, average time of exposition was 21.6 y. Epidermoid carcinoma was the most frequent type of tumor /46.5 %/ of cases/. Smoking plays a supportive role. (authors)

  11. Evaluation of southern Quebec asbestos residues for CO{sub 2} sequestration by mineral carbonation : preliminary result

    Energy Technology Data Exchange (ETDEWEB)

    Huot, F. [Geo-conseils, Cap-Rouge, PQ (Canada); Beaudoin, G.; Hebert, R.; Constantin, M. [Laval Univ., Dept. of Geology and Geological Engineering, Quebec City, PQ (Canada); Bonin, G. [LAB Chrysotile Inc., Black Lake, PQ (Canada); Dipple, G.M. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Earth and Ocean Sciences

    2003-07-01

    Carbon dioxide (CO{sub 2}) sequestration is one approach that can help reduce CO{sub 2} levels in the atmosphere. This paper discusses CO{sub 2} sequestration by mineral carbonation using ultramafic rock-hosted magnesian silicates (serpentine, olivine, talc). The carbonation process produces magnesite, which is a geologically stable and an environmentally safe magnesium carbonate. There are 3 potential CO{sub 2} sinks in southern Quebec that use such silicates. They are: (1) asbestos mill residues, (2) associated mine waste, and (3) ultramafic bedrock. Asbestos is extracted from serpentinized harzburgite located in the Thetford Mines and Asbestos ophiolitic massifs and also from the highly sheared Pennington Sheet. The physical and chemical properties of magnesium silicate deposits greatly determine their carbonation potential. A wide range of properties was observed in samples obtained from almost all asbestos mill residues and waste. The reaction which takes place depends on the mineral content. The kinetics of the reactions are influenced by humidity and grain size.

  12. Magnesium hydroxide extracted from a magnesium-rich mineral for CO2 sequestration in a gas-solid system.

    Science.gov (United States)

    Lin, Pao-Chung; Huang, Cheng-Wei; Hsiao, Ching-Ta; Teng, Hsisheng

    2008-04-15

    Magnesium hydroxide extracted from magnesium-bearing minerals is considered a promising agent for binding CO2 as a carbonate mineral in a gas-solid reaction. An efficient extraction route consisting of hydrothermal treatment on serpentine in HCl followed by NaOH titration for Mg(OH)2 precipitation was demonstrated. The extracted Mg(OH)2 powder had a mean crystal domain size as small as 12 nm and an apparent surface area of 54 m2/g. Under one atmosphere of 10 vol% CO2/N2, carbonation of the serpentine-derived Mg(OH)2 to 26% of the stoichiometric limit was achieved at 325 degrees C in 2 h; while carbonation of a commercially available Mg(OH)2, with a mean crystal domain size of 33 nm and an apparent surface area of 3.5 m2/g, reached only 9% of the stoichiometric limit. The amount of CO2 fixation was found to be inversely proportional to the crystal domain size of the Mg(OH)2 specimens. The experimental data strongly suggested that only a monolayer of carbonates was formed on the crystal domain boundary in the gas-solid reaction, with little penetration of the carbonates into the crystal domain.

  13. High pH microbial ecosystems in a newly discovered, ephemeral, serpentinizing fluid seep at Yanartaş (Chimera), Turkey.

    Science.gov (United States)

    Meyer-Dombard, D'Arcy R; Woycheese, Kristin M; Yargıçoğlu, Erin N; Cardace, Dawn; Shock, Everett L; Güleçal-Pektas, Yasemin; Temel, Mustafa

    2014-01-01

    Gas seeps emanating from Yanartaş (Chimera), Turkey, have been documented for thousands of years. Active serpentinization produces hydrogen and a range of carbon gases that may provide fuel for life. Here we report a newly discovered, ephemeral fluid seep emanating from a small gas vent at Yanartaş. Fluids and biofilms were sampled at the source and points downstream. We describe site conditions, and provide microbiological data in the form of enrichment cultures, Scanning electron microscopy (SEM), carbon and nitrogen isotopic composition of solids, and PCR screens of nitrogen cycle genes. Source fluids are pH 11.95, with a Ca:Mg of ~200, and sediments under the ignited gas seep measure 60°C. Collectively, these data suggest the fluid is the product of active serpentinization at depth. Source sediments are primarily calcite and alteration products (chlorite and montmorillonite). Downstream, biofilms are mixed with montmorillonite. SEM shows biofilms distributed homogeneously with carbonates. Organic carbon accounts for 60% of the total carbon at the source, decreasing downstream to <15% as inorganic carbon precipitates. δ(13)C ratios of the organic carbon fraction of solids are depleted (-25 to -28‰) relative to the carbonates (-11 to -20‰). We conclude that heterotrophic processes are dominant throughout the surface ecosystem, and carbon fixation may be key down channel. δ(15)N ratios ~3‰, and absence of nifH in extracted DNA suggest that nitrogen fixation is not occurring in sediments. However, the presence of narG and nirS at most locations and in enrichments indicates genomic potential for nitrate and nitrite reduction. This small seep with shallow run-off is likely ephemeral, but abundant preserved microterracettes in the outflow and the surrounding area suggest it has been present for some time. This site and others like it present an opportunity for investigations of preserved deep biosphere signatures, and subsurface-surface interactions.

  14. High pH microbial ecosystems in a newly discovered, ephemeral, serpentinizing fluid seep at Yanartaş (Chimaera, Turkey

    Directory of Open Access Journals (Sweden)

    D'Arcy Renee Meyer-Dombard

    2015-01-01

    Full Text Available Gas seeps emanating from ophiolites at Yanartaş (Chimaera, Turkey, have been documented for thousands of years. Active serpentinization produces hydrogen and a range of carbon gases that may provide fuel for life. Here we report a newly discovered, ephemeral fluid seep emanating from a small gas vent at Yanartaş. Fluids and biofilms were sampled at the source and points downstream. We describe site conditions, and provide microbiological data in the form of enrichment cultures, scanning electron microscopy (SEM, carbon and nitrogen isotopic composition of solids, and PCR screens of nitrogen cycle genes. Source fluids are pH 11.95, with a Ca:Mg of ~200, and sediments under the ignited gas seep measure 60°C. Collectively, these data suggest the fluid is the product of active serpentinization at depth. Source sediments are primarily calcite and alteration products (chlorite and montmorillonite. Downstream, biofilms are mixed with montmorillonite. SEM shows biofilms distributed homogeneously with carbonates. Organic carbon accounts for 60% of the total carbon at the source, decreasing downstream to <15% as inorganic carbon precipitates. δ13C ratios of the organic carbon fraction of solids are depleted (−25 to −28 ‰ relative to the carbonates (−11 to −20‰. We conclude that heterotrophic processes are dominant throughout the surface ecosystem, and carbon fixation may be key down channel. δ15N ratios ~ 3‰, and absence of nifH in extracted DNA suggest that nitrogen fixation is not occurring in sediments. However, the presence of narG and nirS at most locations and in enrichments indicates genomic potential for nitrate and nitrite reduction. This small seep with shallow run-off is likely ephemeral, but abundant preserved microterracettes in the outflow and the surrounding area suggest it has been present for some time. This site and others like it present an opportunity for investigations of preserved deep biosphere signatures, and

  15. Brazilian minerals annual report

    International Nuclear Information System (INIS)

    1977-01-01

    Statistics of Brazilian mineral resources and production in 1977 are presented. Data included refer also to economic aspects, market, taxes, government incentives, manpower, exportation, importation, etc [pt

  16. Minerals industry survey, 1984

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    This is the seventh edition of the statistical survey commissioned by the Australian Mining Industry Council. It represents the most comprehensive review of the financial position of the Australian minerals industry and provides timely financial data on the minerals industry. The tables of this survey have been prepared for AMIC by Coopers and Lybrand, Chartered Accountants, based on information supplied to them in confidence by the respondent companies. For the purpose of the survey, the minerals industry has been defined as including exploration for, and extraction and primary processing of, minerals in Australia. The oil and gas industry is not included.

  17. Reagan issues mineral policy

    Science.gov (United States)

    The National Materials and Minerals Program plan and report that President Reagan sent to Congress on April 5 aims to ‘decrease America's minerals vulnerability’ while reducing future dependence on potentially unstable foreign sources of minerals. These goals would be accomplished by taking inventory of federal lands to determine mineral potential; by meeting the stockpile goals set by the Strategic and Critical Material Stockpiling Act; and by establishing a business and political climate that would encourage private-sector research and development on minerals.Now that the Administration has issued its plan, the Subcommittee on Mines and Mining of the House Committee on Interior and Insular Affairs will consider the National Minerals Security Act (NMSA), which was introduced 1 year ago by subcommittee chairman Jim Santini (D-Nev.) [Eos, May 19, 1981, p. 497]. The bill calls for establishing a three-member White-House-level council to coordinate the development of a national minerals policy; amending tax laws to assist the mining industry to make capital investments to locate and produce strategic materials; and creating a revolving fund for the sale and purchase of strategic minerals. In addition, the NMSA bill would allow the secretary of the interior to make previously withdrawn public lands available for mineral development. The subcommittee will hold a hearing on the Administration's plan on May 11. Interior Secretary James Watt has been invited to testify.

  18. International mineral economics

    International Nuclear Information System (INIS)

    Gocht, W.R.; Eggert, R.G.

    1988-01-01

    International Mineral Economics provides an integrated overview of the important concepts. The treatment is interdisciplinary, drawing on the fields of economics, geology, business, and mining engineering. Part I examines the technical concepts important for understanding the geology of ore deposits, the methods of exploration and deposit evaluation, and the activities of mining and mineral processing. Part II focuses on the economic and related concepts important for understanding mineral development, the evaluation of exploration and mining projects, and mineral markets and market models. Finally, Part III reviews and traces the historical development of the policies of international organizations, the industrialized countries, and the developing countries. (orig.)

  19. Mineral statistics yearbook 1994

    International Nuclear Information System (INIS)

    1994-01-01

    A summary of mineral production in Saskatchewan was compiled and presented as a reference manual. Statistical information on fuel minerals such as crude oil, natural gas, liquefied petroleum gas and coal, and of industrial and metallic minerals, such as potash, sodium sulphate, salt and uranium, was provided in all conceivable variety of tables. Production statistics, disposition and value of sales of industrial and metallic minerals were also made available. Statistical data on drilling of oil and gas reservoirs and crown land disposition were also included. figs., tabs

  20. Efecto de la serpentina en la formación de fases mineralógicas y su relación con la resistencia mecánica en sinterizados de mineral de hierro

    Directory of Open Access Journals (Sweden)

    Bedolla, E.

    1995-12-01

    Full Text Available The influence of microstructures formed by serpentine addition on mechanical strength is investigated. It was found that the microstructure formed depends mainly on firing temperature, basicity and serpentine percent. The mineralogical phases present were quantified by the point-count method. The addition of serpentine on acid briquettes (CaO/Si O2 = 0.3, mainly on those fired at 1,275, 1,300 and 1,325 °C, leads to the formation of magnesio-ferrite that diminishes the mechanical strength of fired briquettes, and at the temperature of 1,250 °C the mechanical strength decreases because of the presence of glassy slags. On the other hand, the addition of serpentine on basic briquettes (CaO/Si O2 = 1.2 leads to the formation of olivines and ferrites that improve the mechanical strength of fired briquettes.

    Se estudia la influencia de las microestructuras formadas sobre la resistencia mecánica de mineral de hierro aglomerado con serpentina. Se deduce que la microestructura formada depende de la temperatura de sinterización, de la basicidad y del valor porcentual de serpentina, principalmente. Las fases mineralógicas presentes se cuantificaron utilizando la técnica de conteo por puntos. En briquetas acidas (CaO/SiO2 = 0,3 sinterizadas a 1.275, 1.300 y 1.325 °C, se encontró que la serpentina induce la formación de magnesio-ferritas que traen, como consecuencia, una disminución de la resistencia mecánica, mientras que, a la temperatura de sinterización de 1.250 °C, la aparición de escorias vítreas es la causa principal de la disminución de resistencia. En el caso de briquetas básicas (CaO/SiO2 = 1,2, la adición de serpentina produce la formación de olivinas y calcio-ferritas que originan un aumento de la resistencia mecánica de los sinterizados.

  1. Mineral oil industry

    NARCIS (Netherlands)

    Brasser, L.J.; Suess, M.J.; Grefen, K.; Reinisch, D.W.

    1985-01-01

    In this chapter a general picture is presented of the air pollution aspects in the mineral oil industry. The complete field is covered, starting from drilling operations and the well head up to the delivery of the products to the consumer. A large field of activities as is given by the mineral oil

  2. Vitamins, Minerals, and Mood

    Science.gov (United States)

    Kaplan, Bonnie J.; Crawford, Susan G.; Field, Catherine J.; Simpson, J. Steven A.

    2007-01-01

    In this article, the authors explore the breadth and depth of published research linking dietary vitamins and minerals (micronutrients) to mood. Since the 1920s, there have been many studies on individual vitamins (especially B vitamins and Vitamins C, D, and E), minerals (calcium, chromium, iron, magnesium, zinc, and selenium), and vitamin-like…

  3. Mineral commodity summaries 2018

    Science.gov (United States)

    Ober, Joyce A.

    2018-01-31

    This report is the earliest Government publication to furnish estimates covering 2017 nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for more than 90 individual minerals and materials.

  4. Indochina area mineral prospects

    Energy Technology Data Exchange (ETDEWEB)

    1990-10-05

    Prospects for commercial mining of various minerals are considered for Kampuchea (Cambodia), Laos, Vietnam, Myanmar (Burma) and Thailand. Mineral production is much below its geologic potential for economic and political reasons. Resource potential is limited to tin, tungsten, lead and zinc, barytes and gemstones, and coal. 1 fig.

  5. Chromosomal aberrations in ore miners of Slovakia

    International Nuclear Information System (INIS)

    Beno, M.; Vladar, M.; Nikodemova, D.; Vicanova, M.; Durcik, M.

    1998-01-01

    A pilot study was performed in which the incidence of chromosomal aberrations in lymphocytes of miners in ore mines located in Central Slovakia was monitored and related to lifetime underground radon exposure and to lifetime smoking. The conclusions drawn from the results of the study were as follows: the counts of chromosomal aberrations in lymphocytes of miners were significantly higher than in an age matched control group of white-collar staff; the higher counts of chromosomal aberrations could be ascribed to underground exposure of miners and to smoking; a dependence of chromosomal aberration counts on the exposure to radon could not be assessed. (A.K.)

  6. Protrusive intrusion, dehydration and polymorphism in minerals as possible reason of seismic activity, relation between ophiolite belts and seismic zonation of the territory of Armenia

    Science.gov (United States)

    Harutyunyan, A. V.; Petrosyan, H. M.

    2010-05-01

    In the basis of multiple geological and geophysical data, also on the results of investigations seismic and density properties of rocks at high termobaric conditions, we proposed the petrophisical section and model of evolution of Earth crust of the territory of Armenia. On the proposed model the following interrelated problems are debated: forming of ophiolite belts and volcanic centers, genesis of hydrocarbons by organic and inorganic ways, and also reasons of originating of seismic centers. The reasons of originating of seismic centers in different depths of Earth crust, are miscellaneous. According to the model of Earth crust evolution the ophiolite belts are formed due to permanent protrusive intrusion of serpentinized masses from the foot of the crust (35-50km) into upper horizons. It is natural to assume, that the permanent intrusion of serpentinizd masses through deep faults has drastically occurred accompanying with seismic shakings. This process encourages the development of deep faults. The protrusive intrusion of serpentinized masse accompanied with partial dehydration of serpentinites and serpentinized ultrabasites and new mineral formation. The processes was accompanied also with drastic change of seismic waves and volumes up to 30%. Experiments at high termobaric conditions show, that some minerals undergone polymorphous transformations, accompanied with phase change and drastic change of rocks volume. Particularly plastic calcite, included in the composition of metamorphic rocks to run into the cracks expends and diversifies them. The process described cause some general effects similar to those of the process of dilatancy. Therefore, the protrusive intrusion of serpentinized masses into upper horizons, it dehydrations and polymorphous transformations in different minerals, may be cause of geo-dynamic processes at different depths of Earth crust. It may be assumed, that those processes permanently occur nowadays as well. Comparing the maps of

  7. Taxation of unmined minerals

    International Nuclear Information System (INIS)

    Bremberg, B.P.

    1989-01-01

    This paper reports on the Kentucky Revenue Cabinet which began implementing its controversial unmined minerals tax program. The Revenue Cabinet should complete its first annual assessment under this program in December, 1989. The Revenue Cabinet's initial efforts to collect basic data concerning the Commonwealth's coal bearing lands has yielded data coverage for 5 million of Kentucky's 10 million acres of coal lands. Approximately 1000 detailed information returns have been filed. The returns will be used to help create an undeveloped mineral reserves inventory, determine mineral ownership, and value mineral reserves. This new program is run by the Revenue Cabinet's Mineral Valuation Section, under the Division of Technical Support, Department of Property Taxation. It has been in business since September of 1988

  8. Mineral industry in Australia

    International Nuclear Information System (INIS)

    Parbo, S.A.

    1982-01-01

    The paper reviews the history and growth of the mineral industry in Australia and its significance to the nation's economic growth and overseas trade, particularly over the last twenty years during which time production of coal, iron ore, manganese and mineral sands has increased greatly and new discoveries of petroleum, bauxite and nickel have given rise to major new industries. Australia ranks fourteenths in the value of world trade and is among the world's largest exporters of alumina, iron ore, mineral sands, coal, lead, zinc and nickel. Some details of production, processing and exports of the major minerals are given. Comment is made on the policies and roles of the six State Governments and the Federal Government in respect of ownership and control of the mining, processing and exporting of both energy and non-energy minerals. (orig.) [de

  9. Ilyukhinite (H3O,Na)14Ca6Mn2Zr3Si26O72(OH)2 • 3H2O, a New Mineral of the Eudialyte Group

    Science.gov (United States)

    Chukanov, N. V.; Rastsvetaeva, R. K.; Rozenberg, K. A.; Aksenov, S. M.; Pekov, I. V.; Belakovsky, D. I.; Kristiansen, R.; Van, K. V.

    2017-12-01

    A new eudialyte-group mineral, ilyukhinite, ideally (H3O,Na)14Ca6Mn2Zr3Si26O72(OH)2 · 3H2O, has been found in peralkaline pegmatite at Mt. Kukisvumchorr, Khibiny alkaline pluton, Kola Peninsula, Russia. It occurs as brownish orange, with vitreous luster anhedral grains up to 1 mm across in hydrothermally altered peralkaline rock, in association with aegirine, murmanite, albite, microcline, rhabdophane-(Ce), fluorite, sphalerite and molybdenite. The Mohs hardness is 5; cleavage is not observed. D meas 2.67(2), D calc 2.703 g/cm3. Ilyukhinite is optically uniaxial (-): ω = 1.585(2), ɛ = 1.584(2). The IR spectrum is given. The average chemical composition of ilyukhinite (wt %; electron microprobe, ranges given in parentheses; H2O determined by gas chromatography) is as follows: 3.07 (3.63-4.43) Na2O, 0.32 (0.28-0.52) K2O, 10.63 (10.26-10.90) CaO, 3.06 (2.74-3.22) MnO, 1.15 (0.93-1.37) FeO, 0.79 (0.51-0.89) La2O3, 1.21 (0.97-1.44) Ce2O3, 0.41 (0.30-0.56) Nd2O3, 0.90 (0.77-1.12) TiO2, 10.94 (10.15-11.21) ZrO2, 1.40 (0.76-1.68) Nb2O5, 51.24 (49.98-52.28) SiO2, 1.14 (0.89-1.37) SO3, 0.27 (0.19—0.38) Cl, 10.9(5 )H2O,-0.06-O = C1, total is 98.27. The empirical formula is H36.04(Na3.82K0.20)(Ca5.65Ce0.22La0.14Nd0.07)(Mn1.285Fe0.48)(Zr2.645Ti0.34)Nb0.31Si25.41S0.42Cl0.23O86.82. The crystal structure has been solved ( R = 0.046). Ilyukhinite is trigonal, R3 m; a = 14.1695(6) Å, b = 31.026(1) Å, V = 5394.7(7) Å3, Z = 3. The strongest XRD reflections [ d, Å (I, %) ( hkl)] are 11.44 (82) (101), 7.09 (70) (110), 6.02 (44) (021), 4.371 (89) 205), 3.805 (47) (303, 033), 3.376 (41) (131), 2.985 (100) (315, 128), 2.852 (92) (404). Ilyukhinite was named in memory of Vladimir V. Ilyukhin (1934-1982), an outstanding Soviet crystallographer. The type specimen of ilyukhinite has been deposited in the collection of the Natural History Museum, University of Oslo, Norway.

  10. Mineralized Collagen: Rationale, Current Status, and Clinical Applications

    Directory of Open Access Journals (Sweden)

    Zhi-Ye Qiu

    2015-07-01

    Full Text Available This paper presents a review of the rationale for the in vitro mineralization process, preparation methods, and clinical applications of mineralized collagen. The rationale for natural mineralized collagen and the related mineralization process has been investigated for decades. Based on the understanding of natural mineralized collagen and its formation process, many attempts have been made to prepare biomimetic materials that resemble natural mineralized collagen in both composition and structure. To date, a number of bone substitute materials have been developed based on the principles of mineralized collagen, and some of them have been commercialized and approved by regulatory agencies. The clinical outcomes of mineralized collagen are of significance to advance the evaluation and improvement of related medical device products. Some representative clinical cases have been reported, and there are more clinical applications and long-term follow-ups that currently being performed by many research groups.

  11. Mineral transformations during the dissolution of uranium ore minerals by dissimilatory metal-reducing bacteria

    Science.gov (United States)

    Glasauer, S.; Weidler, P.; Fakra, S.; Tyliszczak, T.; Shuh, D.

    2011-12-01

    Carnotite minerals [X2(UO2)2(VO4)2]; X = K, Ca, Ba, Mn, Na, Cu or Pb] form the major ore of uranium in the Colorado Plateau. These deposits are highly oxidized and contain U(VI) and V(IV). The biotransformation of U(VI) bound in carnotite by bacteria during dissimilatory metal reduction presents a complex puzzle in mineral chemistry. Both U(VI) and V(V) can be respired by metal reducing bacteria, and the mineral structure can change depending on the associated counterion. We incubated anaerobic cultures of S. putrefaciens CN32 with natural carnotite minerals from southeastern Utah in a nutrient-limited defined medium. Strain CN32 is a gram negative bacterium and a terrestrial isolate from New Mexico. The mineral and metal transformations were compared to a system that contained similar concentrations of soluble U(VI) and V(V). Electron (SEM, TEM) microscopies and x-ray spectromicroscopy (STXM) were used in conjunction with XRD to track mineral changes, and bacterial survival was monitored throughout the incubations. Slow rates of metal reduction over 10 months for the treatment with carnotite minerals revealed distinct biotic and abiotic processes, providing insight on mineral transformation and bacteria-metal interactions. The bacteria existed as small flocs or individual cells attached to the mineral phase, but did not adsorb soluble U or V, and accumulated very little of the biominerals. Reduction of mineral V(V) necessarily led to a dismantling of the carnotite structure. Bioreduction of V(V) by CN32 contributed small but profound changes to the mineral system, resulting in new minerals. Abiotic cation exchange within the carnotite group minerals induced the rearrangement of the mineral structures, leading to further mineral transformation. In contrast, bacteria survival was poor for treatments with soluble U(VI) and V(V), although both metals were reduced completely and formed solid UO2 and VO2; we also detected V(III). For these treatments, the bacteria

  12. Mineral facilities of Europe

    Science.gov (United States)

    Almanzar, Francisco; Baker, Michael S.; Elias, Nurudeen; Guzman, Eric

    2010-01-01

    This map displays over 1,700 records of mineral facilities within the countries of Europe and western Eurasia. Each record represents one commodity and one facility type at a single geographic location. Facility types include mines, oil and gas fields, and plants, such as refineries, smelters, and mills. Common commodities of interest include aluminum, cement, coal, copper, gold, iron and steel, lead, nickel, petroleum, salt, silver, and zinc. Records include attributes, such as commodity, country, location, company name, facility type and capacity (if applicable), and latitude and longitude geographical coordinates (in both degrees-minutes-seconds and decimal degrees). The data shown on this map and in table 1 were compiled from multiple sources, including (1) the most recently available data from the U.S. Geological Survey (USGS) Minerals Yearbook (Europe and Central Eurasia volume), (2) mineral statistics and information from the USGS Minerals Information Web site (http://minerals.usgs.gov/minerals/pubs/country/europe.html), and (3) data collected by the USGS minerals information country specialists from sources, such as statistical publications of individual countries, annual reports and press releases of operating companies, and trade journals. Data reflect the most recently published table of industry structure for each country at the time of this publication. Additional information is available from the country specialists listed in table 2.

  13. Definitions of Health Terms: Minerals

    Science.gov (United States)

    ... gov/definitions/mineralsdefinitions.html Definitions of Health Terms : Minerals To use the sharing features on this page, ... National Institutes of Health, Office of Dietary Supplements Minerals Minerals are those elements on the earth and ...

  14. Minerals industry survey 1987

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    This is the eleventh Minerals Industry Survey produced by the Australian Mining Industry Council. It represents an invaluable time series on the minerals industry's financial performance, as well as an up to date description of the industry for the latest financial year. The survey has been conceived as a supplement to and expansion of the various Australian Bureau of Statistics and Bureau of Mineral Resources, Geology and Geophysics publications which describe the exploration, mining and smelting and refining industries in Australia. The tables in this survey have been prepared by Coopers and Lybrand, Chartered Accountants, based on information supplied to them in confidence by the respondent companies.

  15. Characterization of clay minerals

    International Nuclear Information System (INIS)

    Diaz N, C.; Olguin, M.T.; Solache R, M.; Alarcon H, T.; Aguilar E, A.

    2002-01-01

    The natural clays are the more abundant minerals on the crust. They are used for making diverse industrial products. Due to the adsorption and ion exchange properties of these, a great interest for developing research directed toward the use of natural clays for the waste water treatment has been aroused. As part of such researches it is very important to carry out previously the characterization of the interest materials. In this work the results of the mineral and elemental chemical composition are presented as well as the morphological characteristics of clay minerals from different regions of the Mexican Republic. (Author)

  16. Chemistry and Isotopic Composition of Slab-Derived Fluids from Serpentine Mud Volcanoes in the Mariana Forearc

    Science.gov (United States)

    Ryan, J. G.; Menzies, C. D.; Teagle, D. A. H.; Price, R. E.; Sissmann, O.; Wheat, C. G.; Boyce, A.

    2017-12-01

    Geological processes at subduction zone margins control seismicity, plutonism/ volcanism, and geochemical cycling between the oceans, crust, and mantle. The down-going plate experiences dehydration, and associated metamorphism alters the physical properties of the plate interface and mantle wedge. The Mariana convergent margin is non-accretionary, and serpentinite mud volcanoes in the pervasively faulted forearc mark loci of fluid and material egress from the subducting slab and forearc mantle. IODP Expedition 366 drilled into three serpentinite mud volcanoes: Yinazao (13 km depth-to-slab); Fantangisña (14 km) and Asùt Tesoru (18 km), allowing comparison with the previously drilled South Chamorro (18 km) and Conical (19 km) Seamounts. We use the changes in chemistry and isotopic composition of porefluids between seamounts to trace the evolution of the downgoing slab and water-rock interactions in the overlying mantle wedge. Boron isotopes allow investigation of the processes governing prograde metamorphism in the downgoing slab, and combined with O, D/H and Sr isotopes are used to assess the balance between seawater and dehydration fluids during mantle wedge serpentinization. The shallowest depth-to-slab seamounts, Yinazao and Fantangisña, are associated with Ca and Sr-enriched, but otherwise solute poor, low alkalinity fluids of pH 11. In contrast, the Asùt Tesoru seamount fluids are markedly higher in Na and Cl, as well as in tracers like B and K, which are associated with the breakdown of slab sheet silicate phases, and are depleted in Ca and Sr compared to seawater. Higher DIC at this site is attributed to slab carbonate decomposition. The elevated pH ( 12.5) is likely due to Fe2+ oxidation, producing H2 and OH- during serpentinization. Asùt Tesoru porefluids are similar to those studied at South Charmorro and Conical Seamounts that have similar depths to slab, although those sites have distinctly lower Na and Cl, but 3-4 times higher B concentrations

  17. Law of radioactive minerals

    International Nuclear Information System (INIS)

    1980-01-01

    Legal device done in order to standardize and promote the exploration and explotation of radioactive minerals by peruvian and foreign investors. This device include the whole process, since the prospection until the development, after previous auction given by IPEN

  18. Mineral Commodity Summaries 2009

    Science.gov (United States)

    ,

    2009-01-01

    Each chapter of the 2009 edition of the U.S. Geological Survey (USGS) Mineral Commodity Summaries (MCS) includes information on events, trends, and issues for each mineral commodity as well as discussions and tabular presentations on domestic industry structure, Government programs, tariffs, 5-year salient statistics, and world production and resources. The MCS is the earliest comprehensive source of 2008 mineral production data for the world. More than 90 individual minerals and materials are covered by two-page synopses. For mineral commodities for which there is a Government stockpile, detailed information concerning the stockpile status is included in the two-page synopsis. Because specific information concerning committed inventory was no longer available from the Defense Logistics Agency, National Defense Stockpile Center, that information, which was included in earlier Mineral Commodity Summaries publications, has been deleted from Mineral Commodity Summaries 2009. National reserves and reserve base information for most mineral commodities found in this report, including those for the United States, are derived from a variety of sources. The ideal source of such information would be comprehensive evaluations that apply the same criteria to deposits in different geographic areas and report the results by country. In the absence of such evaluations, national reserves and reserve base estimates compiled by countries for selected mineral commodities are a primary source of national reserves and reserve base information. Lacking national assessment information by governments, sources such as academic articles, company reports, common business practice, presentations by company representatives, and trade journal articles, or a combination of these, serve as the basis for national reserves and reserve base information reported in the mineral commodity sections of this publication. A national estimate may be assembled from the following: historically reported

  19. sequenceMiner algorithm

    Data.gov (United States)

    National Aeronautics and Space Administration — Detecting and describing anomalies in large repositories of discrete symbol sequences. sequenceMiner has been open-sourced! Download the file below to try it out....

  20. New evidence for the serpentinization of the Palaeozoic basement of southeastern Sicily from joint 3-D seismic velocity and attenuation tomography

    Science.gov (United States)

    Giampiccolo, E.; Brancato, A.; Manuella, F. C.; Carbone, S.; Gresta, S.; Scribano, V.

    2017-12-01

    In this study, we derived the first 3-D P-wave seismic attenuation images (QP) as well as new 3-D VP and VP/VS models for the crust in southeastern Sicily. We used a large data set of local seismic events occurring in the time span 1994-2013. The results of this tomographic study have important implications on the seismic behaviour of the region. Based on velocity and attenuation images, we identified distinct volumes characterized by different fluid content, which correlate well with seismicity distribution. Moreover, the obtained velocity and attenuation tomographies help us to provide a more complete picture of the crustal structure of the area. High VP, high QP and high VP/VS values have been obtained in the crustal basement, below a depth of 8 km, and may be interpreted as due to the presence of serpentinized peridotites. Accordingly, the new model for the degree of serpentinization, retrieved from VP values, shows that the basement has an average serpentinization value of 96 ± 3 vol.% at 8 km, decreasing to 44 ± 5 vol.% at about 18-20 km.

  1. Preparation and utilization of amorphous siliceous materials from serpentine (Mg3Si2O5(OH)4) by acid treatment; Jamonseki no kofuka kachika ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-30

    Concerning the conversion of serpentine, not only its magnesium component but also silica component, into industrial materials, conditions suitable for the production of porous materials and amorphous silica by acid treatment were evaluated, and the properties of the products were evaluated. The silica resulting from the acid treatment of serpentine comes out in different forms, each reflecting the structure of the parent rock, that is, an amorphous mass of planar particles from antigorite and a fascicular mass of filaments from chrysotile. A microporic structure resulted when a small quantity of magnesium was allowed to remain in the skeleton structure and acid treatment conditions were properly adjusted. Several siliceous compounds were prepared for the purpose of finding use for silica from this rock, and then it was found that high-efficiency production of high-crystallinity compounds was possible and that they were furnished with properties fit for use as materials. Furthermore, study was made about the kaolinite reaction in which serpentine would be directly converted into useful materials. 105 refs., 55 figs., 6 tabs.

  2. Mineral industry statistics 1975

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    Production, consumption and marketing statistics are given for solid fuels (coal, peat), liquid fuels and gases (oil, natural gas), iron ore, bauxite and other minerals quarried in France, in 1975. Also accident statistics are included. Production statistics are presented of the Overseas Departments and territories (French Guiana, New Caledonia, New Hebrides). An account of modifications in the mining field in 1975 is given. Concessions, exploitation permits, and permits solely for prospecting for mineral products are discussed. (In French)

  3. Coastal placer minerals

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; Gujar, A.R.

    to be processed and purified to extract the metal either by sulphate or chloride route. The economical aspects of placer mining would involve the cost to benefit ratio, which would encompass the money Selective sorting has resulted in two distinct sediments... or mineral at the national and international levels. Interestingly, though gold is the most sought metal and the prices per gram keep rising, there are others that are much more costly such as diamond and rare earth metals. Uses of Heavy Minerals...

  4. Mineral commodity summaries 2013

    Science.gov (United States)

    ,

    2013-01-01

    Each chapter of the 2013 edition of the U.S. Geological Survey (USGS) Mineral Commodity Summaries (MCS) includes information on events, trends, and issues for each mineral commodity as well as discussions and tabular presentations on domestic industry structure, Government programs, tariffs, 5-year salient statistics, and world production and resources. The MCS is the earliest comprehensive source of 2012 mineral production data for the world. More than 90 individual minerals and materials are covered by two-page synopses. For mineral commodities for which there is a Government stockpile, detailed information concerning the stockpile status is included in the two-page synopsis. Abbreviations and units of measure, and definitions of selected terms used in the report, are in Appendix A and Appendix B, respectively. “Appendix C—Reserves and Resources” includes “Part A—Resource/Reserve Classification for Minerals” and “Part B—Sources of Reserves Data.” A directory of USGS minerals information country specialists and their responsibilities is Appendix D. The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the MCS 2013 are welcomed.

  5. Mineral commodity summaries 2014

    Science.gov (United States)

    ,

    2014-01-01

    Each chapter of the 2014 edition of the U.S. Geological Survey (USGS) Mineral Commodity Summaries (MCS) includes information on events, trends, and issues for each mineral commodity as well as discussions and tabular presentations on domestic industry structure, Government programs, tariffs, 5-year salient statistics, and world production and resources. The MCS is the earliest comprehensive source of 2013 mineral production data for the world. More than 90 individual minerals and materials are covered by two-page synopses. For mineral commodities for which there is a Government stockpile, detailed information concerning the stockpile status is included in the two-page synopsis. Abbreviations and units of measure, and definitions of selected terms used in the report, are in Appendix A and Appendix B, respectively. “Appendix C—Reserves and Resources” includes “Part A—Resource/Reserve Classification for Minerals” and “Part B—Sources of Reserves Data.” A directory of USGS minerals information country specialists and their responsibilities is Appendix D. The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the MCS 2014 are welcomed.

  6. Action of a clay suspension on an Fe(0) surface under anoxic conditions: Characterization of neoformed minerals at the Fe(0)/solution and Fe(0)/atmosphere interfaces

    International Nuclear Information System (INIS)

    Le Pape, Pierre; Rivard, Camille; Pelletier, Manuel; Bihannic, Isabelle; Gley, Renaud; Mathieu, Sandrine; Salsi, Lise; Migot, Sylvie; Barres, Odile; Villiéras, Frédéric; Michau, Nicolas

    2015-01-01

    Highlights: • Immersion of an Fe(0) foil in a clay suspension at 90 °C and in anoxic conditions. • Magnetite was observed on the atmospheric part. • Iron-rich 7 Å serpentines were observed on the clay suspension part. • A gradient in serpentine cristallochemistry was observed. • A pure Fe–Si phyllosilicate was identified at the Fe(0)/clay suspension contact. - Abstract: To better understand the reaction mechanisms involved at the Fe(0)/clay minerals interface, we investigate in the present study the reaction between an Fe(0) surface and a clay suspension extracted from the Callovo-Oxfordian claystone (COx). Batch experiments were carried out under anoxic conditions in sealed autoclave, at 90 °C to mimic predicted radioactive waste disposal conditions. An Fe(0) foil was introduced into the autoclave so that the lower part of the foil was immersed in the clay suspension while the upper part was contacted with the atmosphere of the experimental setup. After two months, the mineralogical deposits that precipitated at the surface of the Fe(0) foil were analyzed using multiple techniques, namely X-ray diffraction (XRD), scanning/transmission electron microscopy associated to microanalysis (SEM/TEM–EDXS), and micro-spectroscopic measurements (μ-FTIR and μ-Raman). Both parts of the Fe(0) foil were then shown to react: magnetite was the main resulting mineral formed at the Fe(0) surface in the atmospheric conditions whereas serpentine 1:1 phyllosilicates were the main end-products in the clay suspension. The analyses performed on the immersed part of the foil revealed a spatial heterogeneity in both serpentine cristallochemistry and morphology, with a gradient from the Fe(0) contact point toward the clay suspension. A pure Fe–Si phyllosilicate ring was observed at the direct contact point with the Fe(0) foil and a progressive incorporation of Al instead of Fe into the clay phases was identified as deposit thickness increased from the Fe(0) surface to

  7. Perovskite, reaction product of a harzburgite with Jurassic– Cretaceous accretionary wedge fluids (Western Carpathians, Slovakia: evidence from the whole-rock and mineral trace element data

    Directory of Open Access Journals (Sweden)

    Putiš Marián

    2016-04-01

    Full Text Available Perovskite (Prv was discovered in an abyssal harzburgite from a “mélange” type blueschist-bearing accretionary wedge of the Western Carpathians (Meliata Unit, Slovakia. Perovskite-1 formation in serpentinized orthopyroxene may be simplified by the mass-balance reaction: Ca2Si2O6 (Ca-pyroxene-member+2Fe2TiO4 (ulvöspinel molecule in spinel+2H2O+O2=2CaTiO3 (Prv+2SiO2+4FeOOH (goethite. Perovskite-2 occurs in a chlorite-rich blackwall zone separating serpentinite and rodingite veins, and in rodingite veins alone. The bulk-rock trace-element patterns suggest negligible differences from visually and microscopically less (“core” to strongly serpentinized harzburgite due to serpentinization and rodingitization: an enrichment in LREE(La,Ce, Cs, ±Ba, U, Nb, Pb, As, Sb, ±Nd and Li in comparison with HREE, Rb and Sr. The U/Pb perovskite ages at ~135 Ma are interpreted to record the interaction of metamorphic fluids with harzburgite blocks in the Neotethyan Meliatic accretionary wedge. Our LA-ICP-MS mineral study provides a complex view on trace element behaviour during the two stages of rodingitization connected with Prv genesis. The positive anomalies of Cs, U, Ta, Pb, As, Sb, Pr and Nd in Cpx, Opx and Ol are combined with the negative anomalies of Rb, Ba, Th, Nb and Sr in these minerals. The similar positive anomalies of Cs, U, Ta, ±Be, As, Sb found in typical serpentinization and rodingitization minerals, with variable contents of La, Ce and Nd, and negative anomalies of Rb, Ba, Th, Nb and Sr suggest involvement of crustal fluids during MP-LP/LT accretionary wedge metamorphism. LA-ICP-MS study revealed strong depletion in LREE from Prv-1 to Prv-2, and a typically negative Eu (and Ti anomaly for Prv-1, while a positive Eu (and Ti anomaly for Prv-2. Our multi-element diagram depicts enrichment in U, Nb, La, Ce, As, Sb, Pr, Nd and decreased Rb, Ba, Th, Ta, Pb, Sr, Zr in both Prv generations. In general, both Prv generations are very close to the

  8. Fundamental understanding of liquid water effects on the performance of a PEMFC with serpentine-parallel channels

    International Nuclear Information System (INIS)

    Le, Anh Dinh; Zhou Biao

    2009-01-01

    A three-dimensional and unsteady proton exchange membrane fuel cell (PEMFC) model with serpentine-parallel channels has been incorporated to simulate not only the fluid flow, heat transfer, species transport, electrochemical reaction, and current density distribution but also the behaviors of liquid water in the gas-liquid flow of the channels and porous media. Using this general model, the behaviors of liquid water were investigated by performing the motion, deformation, coalescence and detachment of water droplets inside the channels and the penetration of liquid through the porous media at different time instants. The results showed that: tracking the interface of liquid water in a reacting gas-liquid flow in PEMFC can be fulfilled by using volume-of-fluid (VOF) algorithm combined with solving the conservation equations of continuity, momentum, energy, species transport and electrochemistry; the presence of liquid water in the channels has a significant impact on the flow fields, e.g., the gas flow became unevenly distributed due to the blockage of liquid water where the high pressure would be suddenly built up and the reactant gas transport in the channels and porous media would be hindered by liquid water occupation

  9. Feasibility of classification of clay minerals by using PAS

    International Nuclear Information System (INIS)

    Honda, Y; Yoshida, Y; Akiyama, Y; Nishijima, S

    2015-01-01

    After the nuclear power plant disaster, the evaluation of radioactive Cs kept in soil, especially in clay minerals and the elucidation of its movement are urgent subjects to promote decontamination. It is known that the extractable level of Cs depends on the sort of clay minerals. We tried to find the characteristics of clay minerals belonging to phillosilicate group using positron annihilation spectroscopy (PAS) and the relationship between the results of PAS and the amounts of substantially extracted Cs from the clay minerals. The results showed that each clay mineral was found to be distinguishable from other clay minerals by PAS and the extraction rate of Cs was different among those clay minerals, however the direct correlation between the results of PAS and the extraction rates of Cs was not found. (paper)

  10. Intrinsic mineral labeling of edible plants: methods and uses

    International Nuclear Information System (INIS)

    Weaver, C.M.

    1985-01-01

    The fate of minerals can be conveniently studied through intrinsic labeling techniques. The mineral of interest is biologically incorporated into the food in a form that can be distinguished analytically from the natural form of the element. Radiolabels have traditionally been used to study such problems as the uptake of minerals by plants, the gross and subcellular mineral distribution in plant tissues, the form and associations of the deposited mineral, and the bioavailability of minerals to animals and humans. The use of stable (nonradioactive) isotopes as a label offers the potential of safely studying bioavailability of minerals from individual foods in human population groups of all ages using foods processed in normal food handling and processing facilities. 114 references

  11. Contribution in the study of the stability of Callovo-Oxfordian clay rock minerals in the presence of iron at 90 deg C

    International Nuclear Information System (INIS)

    Rivard, Camille

    2011-01-01

    In the context of underground disposal of high-level radioactive waste, it is of prime importance to understand the interaction mechanisms between Callovo-Oxfordian clay rock (COx), selected as a potential host-rock by Andra (French national radioactive waste management agency) and metallic iron, that enters the composition of containers and disposal cells. Interactions between metallic iron and COx clay-rock, COx Callovo-Oxfordian clay fraction (SCOx) and pure clay phases (kaolinite, illite, smectites) were investigated at 90 deg. C under anoxic atmosphere in chlorine solution. In order to study the role of COx non clay minerals, the reactivity of mixtures between SCOx and quartz, calcite, dolomite or pyrite, was also studied. Liquid and solid by-products were characterised by chemical analyses, mineralogical and morphometric techniques, at different scales. In our experimental conditions, major evolutions were observed during the first month, which shows that the oxidation of metallic iron is rapid. The release of iron cations in solution, pH increase (8-10) and Eh decrease (reductive conditions) are responsible for the partial dissolution of initial clay phases. Released iron is involved in the crystallization of Fe-serpentines (odinite or berthierite mainly) or precipitates under the form of magnetite in low amount. Fe-serpentine stability is controlled by the redox conditions as the introduction of dioxygen into the system leads to iron exsolution under the form of iron oxides and hydroxides and precipitation of clay particles with composition close to the initial ones. Whereas carbonates and pyrite do not significantly influence SCOx-metallic iron interactions, reaction pathways are modified in the presence of quartz. Indeed, in such conditions one observes a slight decrease of pH, an increase in Eh, the absence of magnetite and differences in the crystal chemistry of Fe-serpentines that are silica enriched, in comparison with those formed without any quartz

  12. Bone mineral content measurement by bone mineral analyzer

    International Nuclear Information System (INIS)

    Yamamoto, Itsuo; Dokoh, Shigeharu; Fukunaga, Masao; Torizuka, Kanji; Kosaka, Tadako.

    1976-01-01

    With a bone mineral analyzer (Studsvik Bone Scanner 7102), bone mineral content (BMC) was validated using various concentrations of standard CaCO 3 . Seventy-five normal subjects, nineteen patients with rheumathoid arthritis (RA) and twenty-two patients with abnormal thyroid function were investigated by this method. Some inherent problems concerning the present measurements were also discussed. Reproducibility of BMC in sixteen normal subjects during a four months interval was +-4% on the mid-shaft of the radius and +-5% on the distal head of the radius, respectively. Although correlation of the single energy method and the dual energy method with the bone scanner was high (r=0.970), the single energy method was probably underestimated due to the fat layer. BMC in normal subjects was highest in 30th and 40th decades for both males and females, and gradually decreased with aging. Males had higher BMC and BMC/bone width than did females. All of the stage 1 group of RA patients, according to roentgenographic staging, revealed normal BMC, but most of stage 2 and 3 groups had abnormally low BMC, suggesting that progression of the disease may be an important factor in BMC values. The BMC of hyperthyroid patients was low, whereas that of euthyroid patients was normal. Serial measurements of BMC in a hyperparathyroid patient and a hyperthyroid patient revealed distinct recurrence of BMC after treatment. (Evans, J.)

  13. Diseases of uranium miners and other underground miners exposed to radon

    International Nuclear Information System (INIS)

    Samet, J.M.

    1991-01-01

    Excess lung cancer has been demonstrated in many groups of underground miners exposed to radon, including uranium miners and those mining other substances in radon-contaminated mines. In the United States, most underground uranium mines had shut down by the late 1980s, but occupational exposure to radon progeny remains a concern for many other types of underground miners and other underground workers. Worldwide, uranium mining continues, with documented production in Canada, South Africa and other African countries, and Australia. Thus, radon in underground mines remains a significant occupational hazard as the end of the twentieth century approaches.39 references

  14. Selective flotation of phosphate minerals with hydroxamate collectors

    Science.gov (United States)

    Miller, Jan D.; Wang, Xuming; Li, Minhua

    2002-01-01

    A method is disclosed for separating phosphate minerals from a mineral mixture, particularly from high-dolomite containing phosphate ores. The method involves conditioning the mineral mixture by contacting in an aqueous in environment with a collector in an amount sufficient for promoting flotation of phosphate minerals. The collector is a hydroxamate compound of the formula; ##STR1## wherein R is generally hydrophobic and chosen such that the collector has solubility or dispersion properties it can be distributed in the mineral mixture, typically an alkyl, aryl, or alkylaryl group having 6 to 18 carbon atoms. M is a cation, typically hydrogen, an alkali metal or an alkaline earth metal. Preferably, the collector also comprises an alcohol of the formula, R'--OH wherein R' is generally hydrophobic and chosen such that the collector has solubility or dispersion properties so that it can be distributed in the mineral mixture, typically an alkyl, aryl, or alkylaryl group having 6 to 18 carbon atoms.

  15. Geochemistry and mineral chemistry of Shahabad gabbroic intrusion, NW Nourabad, Lorestan province

    Directory of Open Access Journals (Sweden)

    Reza Zarei Sahamieh

    2013-10-01

    Full Text Available The Shahabad gabbroic intrusion, with NW-SE trend cropped out at the boundary of Zagros and Sanandaj-Sirjan zones is composed of olivine gabbro, orthogabbro and troctolite. Plagioclase, clinopyroxene and olivine are the main minerals; and magnetite, titanomagnetite and serpentine are minor and secondary minerals. Microprobe analyses of the minerals show that plagioclase is labradorite, pyroxene diopsidic augite and olivine, chrysolite. The rocks appear to have calc-alkaline and metaluminous nature. The plots of some trace elements and composition of clinopyroxenes in the tectonic discrimination diagrams indicate a volcanic arc environment. In addition, spider diagram pattern of elements shows Sr enrichment and Ti, Nb, Zr and P depletion, typical characteristics of volcanic arc subduction related magmas. Furthermore, close similarity between the patterns of spider diagram for the Shahabad pluton with those of Andean basic rocks suggests that the Shahabad calc-alkaline basic magma may have formed in a subduction environment. Based on geological, geochemical and mineralogical features, formation of the gabbros, as a part of ophiolite mélange, is attributed to a suprasubduction system.

  16. Trace mineral interactions during elevated calcium consumption

    International Nuclear Information System (INIS)

    Smith, K.T.; Luhrsen, K.R.

    1986-01-01

    Elevated calcium consumption is reported to affect trace mineral bioavailability. The authors examined this phenomenon in both single dose radio-label test meals and an eight week feeding trial in rats. In the single dose studies, human milk, cows milk, and various calcium sources were examined in relation to radio-iron and radio-zinc retention. 59 Fe retention was greater from human milk than cows milk. However, when the calcium content of human milk was adjusted (with CaHPO 4 or CaCO 3 ) to equal the level in cows milk, iron retention was depressed. Similarly, when calcium sources (CaCO 3 , CaHPO 4 , hydroxy-apatite, bone meal) were examined at different calcium:metal molar ratios, the degree of inhibition on metal retention varied. In general, phosphate salts were more inhibiting than carbonates. In the feeding trial, calcium was fed in diets at normal (0.5%) or elevated (1.5%) levels. Serum, liver, kidney, and bone trace mineral profiles were obtained. In general, most trace elements showed decreased levels in the tissues. Zinc and iron were most striking, followed by magnesium with minor changes in copper. A high calcium:high mineral supplemented group was also fed. Mixed mineral supplementation prevented all calcium interactions. These data indicate the importance of calcium mineral interactions in bioavailability considerations in both milk sources and in mineral supplementation

  17. Microbially mediated mineral carbonation

    Science.gov (United States)

    Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.

    2010-12-01

    Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O → (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily

  18. Quantitative determination of mineral composition by powder X-ray diffraction

    International Nuclear Information System (INIS)

    Pawloski, G.A.

    1986-01-01

    A method is described of quantitatively determining the mineral composition in a test sample containing a number (m) of minerals from a group (n) of known minerals, wherein n=13, where mless than or equal ton, by x-ray diffraction, comprising: determining from standard samples of the known minerals a set of (n) standard coefficients K/sub j/=(X/sub j//X/sub l/)(I/sub l//I/sub j/) for each mineral (j=2...n) in the group of known minerals (j=2...n) relative to one mineral (l) in the group selected as a reference mineral, where X is the weight fraction of the mineral in a standard sample, and I is the x-ray integrated intensity peak of each mineral obtained from the standard sample; obtaining an x-ray diffraction pattern of the test sample; identifying each of the (m) minerals in the test sample for the x-ray diffraction pattern; calculating the relative weight fractions X/sub j//X/sub l/ for each mineral (j=2...m) compared to the reference mineral (l) from the ratio of the measured highest integrated intensity peak I/sub j/ of each mineral in the test sample to the measured highest integrated intensity peak I/sub l/ of the reference mineral in the test sample, and from the previously determined standard coefficients, X/sub j//X/sub l/=K/sub j/(I/sub j//I/sub l/

  19. Minerals in deserts

    International Nuclear Information System (INIS)

    Smith, G.I.

    1982-01-01

    Almost any kind of mineral deposit can occur in desert areas, and the lack of vegetation and soil cover makes finding them easier. Some kinds of deposits, though, are more likely to occur in deserts than elsewhere. Some of these result from processes genetically related to the present desert climate that improved lower grade deposits of ore. One such process, termed secondary enrichment, is most effective in areas with deep water tables, and many low-grade copper, silver, and uranium deposits have been converted into mineable ore by the downward migration and redeposition of soluble metals. In a desert terrane, placer processes are effective whenever running water flowing over steep slopes erodes outcropping ore bodies and transports and concentrates the heavier ore minerals at lower levels, thus converting low-grade or hard-to-mine bedrock deposits into economically workable concentrations. Other kinds of deposits are better preserved in deserts because the lower rainfall at the surface, and the lower volume of flow and the greater depths to groundwater, result in less destruction of soluble ores; deposits of salines and phosphates are the most notable ores affected by these factors. Still other ore deposits are created as a consequence of the arid climate, mostly because the high evaporation rates operating on standing bodies of water produce brines that can lead directly to concentrations of salts and indirectly to secondary minerals, such as zeolites, that are produced by reaction of silicate minerals with saline waters

  20. Carbonizing bituminous minerals

    Energy Technology Data Exchange (ETDEWEB)

    1921-05-01

    A process for carbonizing bituminous minerals, like oil-shale, in a furnace with addition of air in the presence of heat-receiving material is characterized by the fact that to the feed such solid or liquid material (with the exception of oil) is added, which, through vaporization or heat-binding decomposition or conversion, hinders the establishment of excessive temperatures.

  1. Uruguay minerals fuels

    International Nuclear Information System (INIS)

    Goso, H.

    1967-01-01

    In this report the bases for the development of the necessary works of prospection are exposed on mineral fuels of Uruguay. We have taken the set from: coal, lutitas bituminous, uranium, petroleum and disturbs. In all the cases we have talked about to the present state of the knowledge and to the works that we considered necessary to develop in each case

  2. Some physicochemical aspects of water-soluble mineral flotation.

    Science.gov (United States)

    Wu, Zhijian; Wang, Xuming; Liu, Haining; Zhang, Huifang; Miller, Jan D

    2016-09-01

    Some physicochemical aspects of water-soluble mineral flotation including hydration phenomena, associations and interactions between collectors, air bubbles, and water-soluble mineral particles are presented. Flotation carried out in saturated salt solutions, and a wide range of collector concentrations for effective flotation of different salts are two basic aspects of water-soluble mineral flotation. Hydration of salt ions, mineral particle surfaces, collector molecules or ions, and collector aggregates play an important role in water-soluble mineral flotation. The adsorption of collectors onto bubble surfaces is suggested to be the precondition for the association of mineral particles with bubbles. The association of collectors with water-soluble minerals is a complicated process, which may include the adsorption of collector molecules or ions onto such surfaces, and/or the attachment of collector precipitates or crystals onto the mineral surfaces. The interactions between the collectors and the minerals include electrostatic and hydrophobic interactions, hydrogen bonding, and specific interactions, with electrostatic and hydrophobic interactions being the common mechanisms. For the association of ionic collectors with minerals with an opposite charge, electrostatic and hydrophobic interactions could have a synergistic effect, with the hydrophobic interactions between the hydrophobic groups of the previously associated collectors and the hydrophobic groups of oncoming collectors being an important attractive force. Association between solid particles and air bubbles is the key to froth flotation, which is affected by hydrophobicity of the mineral particle surfaces, surface charges of mineral particles and bubbles, mineral particle size and shape, temperature, bubble size, etc. The use of a collector together with a frother and the use of mixed surfactants as collectors are suggested to improve flotation. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Mariana Forearc Serpentine Mud Volcanoes Harbor Novel Communities of Extremophilic Archaea

    Science.gov (United States)

    Curtis, A. C.; Moyer, C. L.

    2005-12-01

    Since the Eocene (45 Ma) the Pacific Plate has been subducting beneath the Philippine Plate in the western Pacific ocean. This process has given rise to the Mariana Islands. As a direct result of this non-accretionary subduction, the Mariana Island Arc contains a broad forearc zone of serpentinite mud volcanoes located between the island chain and the trench. Forearc faulting, due to high pressure and low temperature build-up, produce slurries of mud and rock that mix with slab derived fluids and rise in conduits. Due to dehydration of the overlying mantle, native rock is converted to serpentinite, which squeezes out at fractures along the sea floor. This results in giant mud volcanoes (~30 km diameter and ~2 km high) that form a chain between 50 and 150 km behind the trench axis. Microbial samples were collected using Jason II from seven mud volcanoes along the length of the forearc and community fingerprinting was applied to genomic DNA using terminal restriction length polymorphism (T-RFLP). The resulting data were compared with traditional clone library and sequence analysis from samples obtained from the southernmost mud volcano, South Chamorro, site 1200, holes D and E, sampled during ODP Leg 195. The dominant archaeal phylotypes found clustered into two groups within the Methanobacteria, a class of anaerobic methanogens and methylotrophs. These phylotypes were detected at three of the seven mud volcanoes sampled and comprised 61% of the archaeal clone library from 1200 E. The first group was most closely related to the order Methanobacteriales, however, these novel phylotypes had similarity values of up to 0.90 at best with some resulting at 0.48. The second novel group of phylotypes were most closely related to order Methanosarcinales, with similarity values in the range of 0.50 to 0.22, indicating a relatively weak association with known phylotypes. At 1200 D, phylotypes associated with non-thermophilic Marine Group I Crenarchaeota were detected

  4. Aggregate and Mineral Resources - Industrial Mineral Mining Operations

    Data.gov (United States)

    NSGIC Education | GIS Inventory — An Industrial Mineral Mining Operation is a DEP primary facility type related to the Industrial Mineral Mining Program. The sub-facility types are listed below:Deep...

  5. Mineral Composition of Organically Grown Wheat Genotypes: Contribution to Daily Minerals Intake

    Science.gov (United States)

    Hussain, Abrar; Larsson, Hans; Kuktaite, Ramune; Johansson, Eva

    2010-01-01

    In this study, 321 winter and spring wheat genotypes were analysed for twelve nutritionally important minerals (B, Cu, Fe, Se, Mg, Zn, Ca, Mn, Mo, P, S and K). Some of the genotypes used were from multiple locations and years, resulting in a total number of 493 samples. Investigated genotypes were divided into six genotype groups i.e., selections, old landraces, primitive wheat, spelt, old cultivars and cultivars. For some of the investigated minerals higher concentrations were observed in selections, primitive wheat, and old cultivars as compared to more modern wheat material, e.g., cultivars and spelt wheat. Location was found to have a significant effect on mineral concentration for all genotype groups, although for primitive wheat, genotype had a higher impact than location. Spring wheat was observed to have significantly higher values for B, Cu, Fe, Zn, Ca, S and K as compared to winter wheat. Higher levels of several minerals were observed in the present study, as compared to previous studies carried out in inorganic systems, indicating that organic conditions with suitable genotypes may enhance mineral concentration in wheat grain. This study also showed that a very high mineral concentration, close to daily requirements, can be produced by growing specific primitive wheat genotypes in an organic farming system. Thus, by selecting genotypes for further breeding, nutritional value of the wheat flour for human consumption can be improved. PMID:20948934

  6. Indústria mineral

    Directory of Open Access Journals (Sweden)

    Iran F. Machado

    1998-08-01

    Full Text Available A INDÚSTRIA mineral brasileira é analisada, de modo sucinto, face aos desafios impostos pela globalização contemporânea. As mudanças profundas ocorridas no contexto internacional na última década, abrangendo as esferas política, econômica, social e institucional, exigem uma reflexão aprofundada sobre o papel a ser desempenhado pelo Brasil no comércio internacional de bens minerais. De um lado, as oportunidades de aproveitamento de jazidas de classe internacional, principalmente na Amazônia, são bastante promissoras. Por outro, não se deve ignorar que: a explotação dessas reservas terá de obedecer a critérios de sustentabilidade, seguindo paradigmas já adotados em países desenvolvidos; o Brasil terá de garantir a sua competitividade diante dos seus principais concorrentes (Austrália, CEI, China e Índia. A questão dos minerais estratégicos é também abordada, com ênfase nas preocupações demonstradas pelo Departamento de Estado dos EUA. Finalmente, são alinhados três cenários possíveis para o desempenho futuro da mineração brasileira, instando-se o governo a dedicar maior atenção ao destino do nosso subsolo.THE MINERAL industry of Brazil is briefly analysed vis-à-vis the challenges imposed by the cruenta globalization process. The profound changes that occurred in the international framework during the last decade, encompassing the political, economic, social, and institutional structures, demand a thorough appraisal about the role to be played by Brazil in the international market of mineral commodities. On one hand, the opportunities open for world class deposits, mainly in the Amazon, are very promising. On the other hand, it is mandatory to take into account that: the exploitation of these reserves shall comply with sound sustainability criteria, following guidelines already adopted by some developed countries; Brazil will have to demonstrate its competitiveness among the major competitors (Australia

  7. Studi Komposisi Mineral Tepung Batu Bukit Kamang Sebagai Bahan Baku Pakan Sumber Mineral

    Directory of Open Access Journals (Sweden)

    Khalil

    2007-04-01

    Full Text Available The study was conducted to determine mineral content of limestone originated from natural deposit of Bukit Kamang for feedstuff. Six samples were prepared and chemically analyzed. The first was limestone in meal form as a product of local milling industry. Another five samples were deposit components with different color of blackish, dark blue, blue, light blue and white. There was 21 kinds of mineral determined which were divided into 3 groups: macros (Ca, P, Mg, Na, K, Cl and S, trace minerals (Mn, Zn, Fe, Cu, Se, Co and Mo and toxic elements (As, F, Hg, Cd, Pb, Ni and Cr. The results showed that Bukit Kamang’s limestone contained considerable high essential minerals of Ca, Se, Fe and Mn. The limestone consisted of 38%-40% Ca, 388 ppm Se, 295 ppm Fe and 205 ppm Mn. There were two toxic elements detected: Pb and Cd, but their concentration was found relatively low: 28 and 7 ppm, respectively.

  8. Absenteeism due to sickness in coal miners

    Energy Technology Data Exchange (ETDEWEB)

    Szymczykiewicz, K.

    1980-01-01

    During two consecutive years sickness absence of 8005 miners from two pit coal mines (A and B) of different geological structure and mechanization degree was analysed. It was found that in mine ''A'' 37% had no sick leaves, whereas in mine ''B''--28%. Absence rate was similar in both mines (though the miners' work and living conditions differed), i.e. 5.21% in mine ''A'', and 5.98% in mine ''B''. Thus work and living conditions do not determine general sickness absence rate. The highest absence in both mines was that of miners frequently falling ill for a long time (approx. 5.5% miners). For the group the number of work disablement days was 28.8 and 26.7, respectively. Underground miners' sickness absence was higher than that of surface workers, the rate being 3.8 and 4.0 and 1.1 and 2.1, respectively. The highest absence was that of miners travelling to work on motor cycles (7.1 and 7.3) and bicycles (6.4 and 6.7). Those working regularly in the first shift were more frequently absent from work than those working in different shifts. Miners living in worse conditions had higher absence rate than those living in flats of a higher standard. Also elderly employees and those having children represented a higher absence rate. The highest absence rate was that of workers having four children, the lowest--that of single persons. In addition, specific absence rate of men, especially due to respiratory and circulatory system diseases, was found to be enhanced by smoking. Absence rate of smokers was 2--3 times higher than that of non-smokers.

  9. EDTA chelation therapy alone and in combination with oral high-dose multivitamins and minerals for coronary disease: The factorial group results of the Trial to Assess Chelation Therapy.

    Science.gov (United States)

    Lamas, Gervasio A; Boineau, Robin; Goertz, Christine; Mark, Daniel B; Rosenberg, Yves; Stylianou, Mario; Rozema, Theodore; Nahin, Richard L; Terry Chappell, L; Lindblad, Lauren; Lewis, Eldrin F; Drisko, Jeanne; Lee, Kerry L

    2014-07-01

    Disodium ethylenediaminetetraacetic acid (EDTA) reduced adverse cardiac outcomes in a factorial trial also testing oral vitamins. This report describes the intent-to-treat comparison of the 4 factorial groups overall and in patients with diabetes. This was a double-blind, placebo-controlled, 2 × 2 factorial multicenter randomized trial of 1,708 post-myocardial infarction (MI) patients ≥50 years of age and with creatinine ≤2.0 mg/dL randomized to receive 40 EDTA chelation or placebo infusions plus 6 caplets daily of a 28-component multivitamin-multimineral mixture or placebo. The primary end point was a composite of total mortality, MI, stroke, coronary revascularization, or hospitalization for angina. Median age was 65 years, 18% were female, 94% were Caucasian, 37% were diabetic, 83% had prior coronary revascularization, and 73% were on statins. Five-year Kaplan-Meier estimates for the primary end point was 31.9% in the chelation + high-dose vitamin group, 33.7% in the chelation + placebo vitamin group, 36.6% in the placebo infusion + active vitamin group, and 40.2% in the placebo infusions + placebo vitamin group. The reduction in primary end point by double active treatment compared with double placebo was significant (hazard ratio 0.74, 95% CI 0.57-0.95, P = .016). In patients with diabetes, the primary end point reduction of double active compared with double placebo was more pronounced (hazard ratio 0.49, 95% CI 0.33-0.75, P < .001). In stable post-MI patients on evidence-based medical therapy, the combination of oral high-dose vitamins and chelation therapy compared with double placebo reduced clinically important cardiovascular events to an extent that was both statistically significant and of potential clinical relevance. Copyright © 2014 The Authors. Published by Mosby, Inc. All rights reserved.

  10. Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David; Banfield, Jillian F.

    2010-06-22

    Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence ({mu}XRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from a creek and abandoned mine; these samples are dominated by iron oxyhydroxide-coated structures with sheath, stalk, and filament morphologies. In addition, we characterized the mineralized products of an iron-oxidizing, stalk-forming bacterial culture isolated from the mine. In both natural and cultured samples, microbial polymers were found to be acidic polysaccharides with carboxyl functional groups, strongly spatially correlated with iron oxyhydroxide distribution patterns. Organic fibrils collect FeOOH and control its recrystallization, in some cases resulting in oriented crystals with high aspect ratios. The impact of polymers is particularly pronounced as the materials age. Synthesis experiments designed to mimic the biomineralization processes show that the polysaccharide carboxyl groups bind dissolved iron strongly but release it as mineralization proceeds. Our results suggest that carboxyl groups of acidic polysaccharides are produced by different microorganisms to create a wide range of iron oxyhydroxide biomineral structures. The intimate and potentially long-term association controls the crystal growth, phase, and reactivity of iron oxyhydroxide nanoparticles in natural systems.

  11. Outlook 96: Minerals and Energy

    International Nuclear Information System (INIS)

    1996-01-01

    Papers discussing the future of Australia's minerals and energy are presented under the following headings: Australia in the global minerals and energy markets; minerals exploration; steelmaking raw materials; aluminium and alumina; gold; nickel; base metals; titanium minerals; energy for a sustainable future; electricity; electricity in Asia; crude oil; coal trade; natural gas in Australia and uranium. Relevant papers are individually indexed/abstracted. Tabs., figs., refs

  12. International availability of energy minerals

    Energy Technology Data Exchange (ETDEWEB)

    White, N A [Norman White Associates, London (UK)

    1979-06-01

    Whereas the ultimate world supply of energy minerals - defined as fossil fuels and fissile minerals - is controlled by geological factors, the actual supply at any particular time is controlled by economic feasibility, technological innovations and/or political decisions. This paper identifies and discusses the principal uncertainties surrounding the international availability of energy minerals from now until the end of the century. A brief comparison is also made between energy and non-energy minerals.

  13. The bismuth miners study

    International Nuclear Information System (INIS)

    Grosche, B.; Kreuzer, M.; Kreisheimer, M.; Schnelzer, M.; Tschense, A.; Gottschalk, K.

    2005-01-01

    The Federal Radiation Protection Office carried out a retrospective cohort study on some 60,000 former employees of the SAG/SDAG Wismut. The purpose of the study was to validate the radon-related risk of acquiring lung cancer previously calculated from 11 jointly evaluated studies among miners on the basis of an independent, homogeneous data record of comparable size. A further goal was to study the risk of acquiring extrapulmonal tumours. This paper only briefly describes the sampling, design and methods used in the study, as these were already presented during the Radon Status Talks. The first follow-up on the cohort was completed in 2003. Around this time a job exposure matrix (JEM) suitable for scientific inquiries was made available by the professional miners' association and the roof organisation of professional trade associations (HVBG). This paper is the first to report on the outcome of the risk analysis in direct comparison with the results found by BEIR

  14. Iodine mineral waters

    Directory of Open Access Journals (Sweden)

    Iluta Alexandru

    2011-11-01

    Full Text Available Iodine mineral waters are found especially in sub-Carpathian region, also in regions with Salif deposits. Waters are currently used iodine in drinking cure for chaps and Basedow. Are also indicated in balneology. Iodine water containing at least 1 mg L, there is pure iodine is usually given the nature of other types of mineral waters further: sodium chlorinated water (Bazna (50-70 mg iodine / l, Baile Govora (50 - 70 mg / l, Bălţăteşti (4-5 mg / l, salted Monteoru (30 mg / l, mine water mixed alkaline chlorination, sulphate, which are indicated for crenoterapie (hypo or isotonic to the bathrooms Olăneşti or Călimăneşti-Căciulata.

  15. Rock and mineral magnetism

    CERN Document Server

    O’Reilly, W

    1984-01-01

    The past two decades have witnessed a revolution in the earth sciences. The quantitative, instrument-based measurements and physical models of. geophysics, together with advances in technology, have radically transformed the way in which the Earth, and especially its crust, is described. The study of the magnetism of the rocks of the Earth's crust has played a major part in this transformation. Rocks, or more specifically their constituent magnetic minerals, can be regarded as a measuring instrument provided by nature, which can be employed in the service of the earth sciences. Thus magnetic minerals are a recording magnetometer; a goniometer or protractor, recording the directions of flows, fields and forces; a clock; a recording thermometer; a position recorder; astrain gauge; an instrument for geo­ logical surveying; a tracer in climatology and hydrology; a tool in petrology. No instrument is linear, or free from noise and systematic errors, and the performance of nature's instrument must be assessed and ...

  16. Penggunaan Formula Mineral Lokal dalam Ransum Ayam Petelur

    Directory of Open Access Journals (Sweden)

    Khalil

    2010-08-01

    Full Text Available A mineral formula composed of three locally available materials: limestone originated from Bukit Kamang of West Sumatra, freshwater oyster shell and bone meal and fortified with micro minerals of Cu, Zn and I was investigated as mineral supplement for diet of laying hens. The experimental diets were: P0 (diet contained of 6% commercial mineral, P1 (diet contained of 6% local mineral, P2 (diet contained of 6% Bukit Kamangs’ limestone and P3 (diet contained of 6% fresh water oyster shell meal. The total of four experimental diets was then fed to 120 laying hens. The hens were divided into 3 groups based on body weight: heavy, medium and light. Each group was subdivided into 4 subgroups in accordance with number of treatments, so that each treatment consisted of 3 replicates containing of 10 hens. Parameters measured included: feed intake, hen-day egg production, feed conversion ratio (FCR, eggshell quality, mineral retention and mineral composition of tibia bone. Data were subjected to statistical analysis using variance analysis in a completely block design with 4 treatments and 3 blocks as replicates The results showed that the egg weight and eggshell qualities were found not significantly difference, but different mineral sources gave significant effect on egg production and bone mineralization. The laying performances and tibia bone weight of chickens fed diet mixed with the local mineral formula were found not significantly different with those fed diet mixed with commercial formula, but significantly better (P<0.05 than those of fed diet mixed with only limestone or oyster shell. Hens fed with diet mixed with Bukit Kamangs’ limestone showed better performances and heavier tibia bone than those fed with diet mixed with oyster shell. It was concluded that the local mineral formula could be used as sole mineral source for laying hens. The nutritive value of Bukit Kamangs’ limestone was better than that of fresh water oyster shell.

  17. Characterization lithium mineralized pegmatite

    International Nuclear Information System (INIS)

    Pereira, E.F.S.; Luz Ferreira, O. da; Cancado, R.Z.L.

    1986-01-01

    Lithium economic importance has increased in the last years. In Brazil its reserves, generally pegmatites bodies, are found in Itinga-Aracuai-MG. This study of characterization belongs to a global plan of lithium mineralized bodies research of 'Arqueana de Minerios e Metais Ltda', which purpose is to give subsidies for implementation of pegmatite unit, in order to make better use of them. (F.E.) [pt

  18. 76 FR 6110 - Conflict Minerals

    Science.gov (United States)

    2011-02-03

    ...-10] RIN 3235-AK84 Conflict Minerals AGENCY: Securities and Exchange Commission. ACTION: Proposed rule...'') and would require any such issuer for which conflict minerals are necessary to the functionality or... body of its annual report whether its conflict minerals originated in the Democratic Republic of the...

  19. Flotation of sulphide minerals 1990

    Energy Technology Data Exchange (ETDEWEB)

    Forssberg, K S.E. [ed.; Luleaa University of Technology, Luleaa (Sweden). Division of Mineral Processing

    1991-01-01

    A total of 27 papers presented at the workshop on flotation of sulphide minerals, reprinted from the International Journal of Mineral Processing, vol. 33, nos. 1-4, are included in this book. They cover various aspects of flotation of such minerals as chalcopyrite, pyrrhotite, galena, malachite and pyrite.

  20. Digital mineral logging system

    International Nuclear Information System (INIS)

    West, J.B.

    1980-01-01

    A digital mineral logging system acquires data from a mineral logging tool passing through a borehole and transmits the data uphole to an electronic digital signal processor. A predetermined combination of sensors, including a deviometer, is located in a logging tool for the acquisition of the desired data as the logging tool is raised from the borehole. Sensor data in analog format is converted in the logging tool to a digital format and periodically batch transmitted to the surface at a predetermined sampling rate. An identification code is provided for each mineral logging tool, and the code is transmitted to the surface along with the sensor data. The self-identifying tool code is transmitted to the digital signal processor to identify the code against a stored list of the range of numbers assigned to that type of tool. The data is transmitted up the d-c power lines of the tool by a frequency shift key transmission technique. At the surface, a frequency shift key demodulation unit transmits the decoupled data to an asynchronous receiver interfaced to the electronic digital signal processor. During a recording phase, the signals from the logging tool are read by the electronic digital signal processor and stored for later processing. During a calculating phase, the stored data is processed by the digital signal processor and the results are outputted to a printer or plotter, or both

  1. Concentration of gold, sulphide minerals and uranium oxide minerals by flotation from ores and metallurgical plant products

    International Nuclear Information System (INIS)

    Weston, D.

    1974-01-01

    A process for the recovery by froth flotation of gold and mineral values selected from the group consisting of gold bearing minerals, platinum group minerals, silver group minerals, and uranium group minerals, from ores and metallurgical plant products containing at least gold and at least one of the other said minerals comprising: subjecting a suitably prepared pulp of the material to mechanical agitation in at least one agitation conditioning stage wherein the pH of the said pulp has been lowered with an acid agent to an optimum pH point within the pH range of about 1.5 to 5.0 and wherein the agitation conditioning is for a sufficient period of time to bring about heavy activation of at least one of the said mineral values in at least one subsequent mechanical agitation conditioning stage wherein the said pulp is further agitation conditioned for a sufficient period of time and at an optimum pH point in the pH range of about 6.0 to 11.0 in the presence of at least one collector selected from the group of sulfhydryl anionic collectors to produce the said heavy activation of at least gold and at least one of the other said mineral values; and subsequently in the presence of a frother subjecting and said agitation conditioned pulp to flotation to produce a concentrate enriched in gold and at least one of the othersaid mineral values, and a tailings product impoverished in at least gold and at least one of the other said mineral values

  2. Dynamic contents of energy and organic nutrient in steppe growths of the Mohelenská Serpentine Steppe National Nature Reserve

    Directory of Open Access Journals (Sweden)

    Pavel Veselý

    2006-01-01

    Full Text Available The aim of the study was to determine the dynamics in the content of organic nutrients, ash and energy in dry matter of growths within the Mohelenská Serpentine Steppe National Nature Reserve (NPR, and to document their initial nutritive value before the intended grazing. Plant samples in 1995 and 1996 during the growing season in 14-days intervals from the area of 3 × 1 m2. Amounts of dry matter, fibre, nitrogen substances, fat and ashes were determined in growths according to the ANONYM (2001. Nitrogen-free extract substances (BNLV were determined by final calculating; BE, ME, NEL, NEV, PDIN and PDIE were calculated using the regression equations (VESELÝ and ZEMAN, 1995, 1997. Combining ratio (SP was calculated according to the relation: SP = PDIN (g/NEL (MJ. The dynamics of the contents of dry matter, organic nutrients, ashes and energy were assessed in the growth during the vegetation period and the dynamics was compared with standardized requirements of sheep (no pregnant ewe. Regression and correlation relations for nutrition value of the growths during vegetation period were calculated by use of mathematical-statistical analysis. Only statistically significantly (P<0.05 different parameters form the zero are presented in the paper. The content of dry matter in the growths culminated in summer months (places D8, E13, B17 and it was accompanied by depression in autumn months. After the highest content of crude protein, PDIN and PDIE recorded in spring months summer depression (August followed, this depression was partly balanced by autumn growth of vegetation. The content of ash in steppe growths increased during evaluated period. Similar tendency was registered for fat. Also the contents of fibre and BNLV linearly increased. The contents of nitrogen nutrients and energy corresponded with standardized requirements for sheep during whole vegetation period. Conversely the content of fibre highly exceeded the requirement except in spring

  3. Strength and Deformation Rate of Plate Boundaries: The Rheological Effects of Grain Size Reduction, Structure, and Serpentinization.

    Science.gov (United States)

    Montesi, L.; Gueydan, F.

    2016-12-01

    stress). While this can increase strain rate by another factor of 1000, another process must generate the lithospheric thickness variation in the first place. One possibility is serpentinization, which reduces the strength of the brittle crust, especially when coupled with the development of a fabric in brittle faults.

  4. Occurrence model for magmatic sulfide-rich nickel-copper-(platinum-group element) deposits related to mafic and ultramafic dike-sill complexes: Chapter I in Mineral deposit models for resource assessment

    Science.gov (United States)

    Schulz, Klaus J.; Woodruff, Laurel G.; Nicholson, Suzanne W.; Seal, Robert R.; Piatak, Nadine M.; Chandler, Val W.; Mars, John L.

    2014-01-01

    Magmatic sulfide deposits containing nickel (Ni) and copper (Cu), with or without (±) platinum-group elements (PGE), account for approximately 60 percent of the world’s nickel production. Most of the remainder of the Ni production is derived from lateritic deposits, which form by weathering of ultramafic rocks in humid tropical conditions. Magmatic Ni-Cu±PGE sulfide deposits are spatially and genetically related to bodies of mafic and/or ultramafic rocks. The sulfide deposits form when the mantle-derived mafic and/or ultramafic magmas become sulfide-saturated and segregate immiscible sulfide liquid, commonly following interaction with continental crustal rocks.

  5. Microbial diversity in a submarine carbonate edifice from the serpentinizing hydrothermal system of the Prony Bay (New Caledonia over a 6-year period.

    Directory of Open Access Journals (Sweden)

    Anne ePostec

    2015-08-01

    Full Text Available Active carbonate chimneys from the shallow marine serpentinizing Prony Hydrothermal Field were sampled 3 times over a 6 years period at site ST09. Archaeal and bacterial communities composition was investigated using PCR-based methods (clone libraries, Denaturating Gel Gradient Electrophoresis, quantitative PCR targeting 16S rRNA genes, methyl coenzyme M reductase A and dissimilatory sulfite reductase subunit B genes. Methanosarcinales (Euryarchaeota and Thaumarchaea were the main archaeal members. The Methanosarcinales, also observed by epifluorescent microscopy and FISH, consisted of two phyotypes that were previously solely detected in two other serpentinitzing ecosystems (The Cedars and Lost City Hydrothermal Field. Surprisingly, members of the hyperthermophilic order Thermococcales were also found which may indicate the presence of a hot subsurface biosphere. The bacterial community mainly consisted of Firmicutes, Chloroflexi, Alpha-, Gamma-, Beta- and Delta-proteobacteria and of the candidate division NPL-UPA2. Members of these taxa were consistently found each year and may therefore represent a stable core of the indigenous bacterial community of the PHF chimneys. Firmicutes isolates representing new bacterial taxa were obtained by cultivation under anaerobic conditions. Our study revealed diverse microbial communities in PHF ST09 related to methane and sulfur compounds that share common populations with other terrestrial or submarine serpentinizing ecosystems.

  6. Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN

    Directory of Open Access Journals (Sweden)

    Penny Lea Morrill

    2014-11-01

    Full Text Available Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. CO was consumed in the live experiments but not in the killed controls and the residual CO in the live experiments became enriched in 13 C. The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰. Phospholipid fatty acid concentrations and δ13C values suggest limited incorporation of carbon from CO into microbial lipids. This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth. Environmental DNA sequencing of spring fluids collected at the same time as the addition experiments yielded a large proportion of Hydrogenophaga-related sequences, which is consistent with previous metagenomic data indicating the potential for these taxa to utilize CO.

  7. Microbial diversity in a submarine carbonate edifice from the serpentinizing hydrothermal system of the Prony Bay (New Caledonia) over a 6-year period.

    Science.gov (United States)

    Postec, Anne; Quéméneur, Marianne; Bes, Méline; Mei, Nan; Benaïssa, Fatma; Payri, Claude; Pelletier, Bernard; Monnin, Christophe; Guentas-Dombrowsky, Linda; Ollivier, Bernard; Gérard, Emmanuelle; Pisapia, Céline; Gérard, Martine; Ménez, Bénédicte; Erauso, Gaël

    2015-01-01

    Active carbonate chimneys from the shallow marine serpentinizing Prony Hydrothermal Field were sampled 3 times over a 6 years period at site ST09. Archaeal and bacterial communities composition was investigated using PCR-based methods (clone libraries, Denaturating Gel Gradient Electrophoresis, quantitative PCR) targeting 16S rRNA genes, methyl coenzyme M reductase A and dissimilatory sulfite reductase subunit B genes. Methanosarcinales (Euryarchaeota) and Thaumarchaea were the main archaeal members. The Methanosarcinales, also observed by epifluorescent microscopy and FISH, consisted of two phylotypes that were previously solely detected in two other serpentinitzing ecosystems (The Cedars and Lost City Hydrothermal Field). Surprisingly, members of the hyperthermophilic order Thermococcales were also found which may indicate the presence of a hot subsurface biosphere. The bacterial community mainly consisted of Firmicutes, Chloroflexi, Alpha-, Gamma-, Beta-, and Delta-proteobacteria and of the candidate division NPL-UPA2. Members of these taxa were consistently found each year and may therefore represent a stable core of the indigenous bacterial community of the PHF chimneys. Firmicutes isolates representing new bacterial taxa were obtained by cultivation under anaerobic conditions. Our study revealed diverse microbial communities in PHF ST09 related to methane and sulfur compounds that share common populations with other terrestrial or submarine serpentinizing ecosystems.

  8. Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN.

    Science.gov (United States)

    Morrill, Penny L; Brazelton, William J; Kohl, Lukas; Rietze, Amanda; Miles, Sarah M; Kavanagh, Heidi; Schrenk, Matthew O; Ziegler, Susan E; Lang, Susan Q

    2014-01-01

    Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO) utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. CO was consumed in the live experiments but not in the killed controls and the residual CO in the live experiments became enriched in (13)C. The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰. Phospholipid fatty acid concentrations and δ(13)C values suggest limited incorporation of carbon from CO into microbial lipids. This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth. Environmental DNA sequencing of spring fluids collected at the same time as the addition experiments yielded a large proportion of Hydrogenophaga-related sequences, which is consistent with previous metagenomic data indicating the potential for these taxa to utilize CO.

  9. Deep long-period earthquakes west of the volcanic arc in Oregon: evidence of serpentine dehydration in the fore-arc mantle wedge

    Science.gov (United States)

    Vidale, John E.; Schmidt, David A.; Malone, Stephen D.; Hotovec-Ellis, Alicia J.; Moran, Seth C.; Creager, Kenneth C.; Houston, Heidi

    2014-01-01

    Here we report on deep long-period earthquakes (DLPs) newly observed in four places in western Oregon. The DLPs are noteworthy for their location within the subduction fore arc: 40–80 km west of the volcanic arc, well above the slab, and near the Moho. These “offset DLPs” occur near the top of the inferred stagnant mantle wedge, which is likely to be serpentinized and cold. The lack of fore-arc DLPs elsewhere along the arc suggests that localized heating may be dehydrating the serpentinized mantle wedge at these latitudes and causing DLPs by dehydration embrittlement. Higher heat flow in this region could be introduced by anomalously hot mantle, associated with the western migration of volcanism across the High Lava Plains of eastern Oregon, entrained in the corner flow proximal to the mantle wedge. Alternatively, fluids rising from the subducting slab through the mantle wedge may be the source of offset DLPs. As far as we know, these are among the first DLPs to be observed in the fore arc of a subduction-zone system.

  10. Low back pain and lumbar angles in Turkish coal miners

    Energy Technology Data Exchange (ETDEWEB)

    Sarikaya, S.; Ozdolap, S.; Gumustas, S.; Koc, U. [Zonguldak Karaelmas University, Zonguldak (Turkey). Faculty of Medicine

    2007-02-15

    This study was designed to assess the incidence of low back pain among Turkish coal miners and to investigate the relationship between angles of the lumbar spine and low back pain in coal miners. Fifty underground workers (Group I) and 38 age-matched surface workers (Group II) were included in the study. All the subjects were asked about low back pain in the past 5 years. The prevalence of low back pain was higher in Group I than in Group II (78.0%, 32.4%, respectively, P {lt} 0.001). The results of the study showed that low back pain occurred in 78.0% of Turkish coal miners. Although the nature of the occupation may have influenced coal miners' lumbar spinal curvature, lumbar angles are not a determinant for low back pain in this population. Further extensive studies involving ergonomic measurements are needed to validate our results for Turkish coal mining industry.

  11. RADIOMETRIC TECHNIQUES IN HEAVY MINERAL EXPLORATION AND EXPLOITATION

    NARCIS (Netherlands)

    DEMEIJER, RJ; TANCZOS, IC; STAPEL, C

    1994-01-01

    In recent years the Environmental Research Group of the KVI has been developing a number of radiometric techniques that may be employed in mineral sand exploration. These techniques involve: radiometric fingerprinting for assessing sand provenances and mineralogical composition; thermoluminescence

  12. Study of mortality of Ontario miners, 1955-1977. Pt. 1

    International Nuclear Information System (INIS)

    Muller, J.; Kusiak, R.A.; Wheeler, W.C.; Suranyi, G.; Gentleman, J.F.

    1983-05-01

    A mortality study of Ontario Mines covering the period of 1955 to 1977 was carried out. There are 50,201 men in the study for a total of 754,391 person-years and 6,757 deaths were observed in this population over the period of the study. The most serious hazard in this population was death due to violent causes. The population was subdivided into gold miners, nickel-copper miners, iron ore miners, other ore miners, mixed ore miners, and uranium miners. Only in certain types of miners was an increase in deaths from non-neoplastic lung disease detectable. A significant increase was noted in underground gold miners, mixed ore miners and in uranium miners. This increase was largely due to increased death rates from silicosis and chronic interstitial pneumonia. In addition there were 43 deaths due to silicotuberculosis in gold miners and 36 deaths due to the same cause in mixed ore miners. It is estimated that the total difference between observed and expected deaths from silicosis and chronic interstitial pneumonia as well as from silicotuberculosis which was observed gold miners and in mixed ore miners can actually be attributed to gold mining only. Increased cancer risk in non-uranium miners is observed for cancer of the trachea, bronchus and lung in full-time underground gold miners and full-time underground mixed ore miners, and cancer of the stomach in full-time underground gold miners. It is assumed that the increased risk of lung cancer in both these groups of miners is in fact due to underground gold mining only. As to uranium miners, previous studies have already demonstrated an increased lung cancer risk in these men and this finding was confirmed in this study. Men who have also worked for Eldorado Nuclear Limited show a siginificantly increased risk of death from all causes and from all disease causes

  13. Mineral facilities of Africa and the Middle East

    Science.gov (United States)

    Eros, J.M.; Candelario-Quintana, Luissette

    2006-01-01

    This map displays over 1,500 mineral facilities in Africa and the Middle East. The mineral facilities include mines, plants, mills, or refineries of aluminum, cement, coal, copper, diamond, gold, iron and steel, nickel, platinum-group metals, salt, and silver, among others. The data used in this poster were compiled from multiple sources, including the 2004 USGS Minerals Yearbook (Africa and Middle East volume), Minerals Statistics and Information from the USGS Web site (http://minerals.usgs.gov/minerals/), and data collected by USGS minerals information country specialists. Data reflect the most recent published table of industry structure for each country. Other sources include statistical publications of individual countries, annual reports and press releases of operating companies, and trade journals. Due to the sensitivity of some energy commodity data, the quality of these data should be evaluated on a country-by-country basis. Additional information and explanation is available from the country specialists. See Table 1 for general information about each mineral facility site including country, location and facility name, facility type, latitude, longitude, mineral commodity, mining method, main operating company, status, capacity, and units.

  14. Nuclear minerals in Pakistan

    International Nuclear Information System (INIS)

    Mansoor, M.

    2005-01-01

    Strategic importance of Nuclear Minerals was recognized during early formative years of the Pakistan Atomic Energy Commission, and prospecting for uranium was started in Dera Ghazi Khan in collaboration with the Geological Survey of Pakistan (GSP) as early as 1961. Later, the responsibility for countrywide surveys and exploration was fully entrusted with PAEC and in this respect a Directorate of Nuclear Minerals(DNM) was established in 1966 at Lahore. Later, DNM was shifted to the Atomic Energy Centre (AEC), Lahore building and renamed as Atomic Energy Minerals Centre. It has state-of-the-art Chemistry, Mineralogy, Remote Sensing and Electronics Laboratories and an Ore Processing Pilot Plant. The Centre has Prospecting, Exploration, Geophysics, Geochemistry, Geo-tectonics, Mining and Drilling Sections. Regional Offices have been established to facilitate work at Karachi, Quetta and Peshawar. Siwaliks were recognized as a favorable geological formation of prime importance. Sandstone-shale sequence of Siwaliks Formation is exposed in all provinces of Pakistan and in Azad Jammu and Kashmir (AJK), broadly categorized into Rajanpur-Dera Ghazi Khan, Bannu Basin-Kohat Plateau and Potwar-AJK zones. Baghalchur, Nangar Nai and Taunsa uranium deposits have been discovered in the Rajanpur- D.G. Khan Zone. Qabul Khel and Shanawah Uranium deposits have been discovered in the Shanawah-Kohat Plateau Zone. Prospection and exploration is in progress. The first uranium mine was opened at Baghalchur, and uranium mill was established at D.G Khan in 1977-78 all by indigenous effort. The uranium mine was the most advanced and mechanized mine of that time in the country. Later, a second uranium mine was opened at Qabul Khel in 1992, which was based on a new and advanced in situ leach technology, developed to suit local geological and ore zone parameters. Mining of Nanganai and Taunsa Deposits was started respectively in 1996 and 2002, and is also based on in situ leach technology which is

  15. Minerals and rumen function

    International Nuclear Information System (INIS)

    Smith, R.H.

    1984-01-01

    The mechanisms are discussed of some clinical disorders, characteristic only of ruminants and related to the effects of abnormal mineral intake on rumen function. With particular attention to tropical conditions, consideration is given to: (a) the possible effects of phosphorus deficiency on rumen microbial activity; (b) the depression of rumen microbial synthesis in sulphur deficiency; (c) the inhibition of magnesium absorption from the forestomachs; and (d) the involvement of the rumen microorganisms in leading to copper and vitamin B 12 deficiencies as a result of low intakes of cobalt. (author)

  16. Reducing coal miner absenteeism

    Energy Technology Data Exchange (ETDEWEB)

    Peters, R.H.; Clingan, M.R. (Bureau of Mines, PA (USA). Pittsburgh Research Center)

    1989-09-01

    High absenteeism at coal mines can seriously affect safety and hamper productivity. Several effective strategies for achieving high attendance which mine operators may not have considered are presented and a method is proposed for implementing programs for minimizing absenteeism among coal miners. The best strategies for improving attendance will vary according to the needs and circumstances of the particular mine, however, the process for establishing such a program is relatively invariant. A four-stage process is recommended; evaluate data from prior attendance records, communicate attendance goals and policy, develop and implement an attendance promotion program, and recycle. 12 refs., 5 figs.

  17. United States mineral resources

    Science.gov (United States)

    Brobst, Donald A.; Pratt, Walden P.

    1973-01-01

    The work on this volume began in January 1972, but in a broader sense its production began many years ago. The chapters were written by geologists most of whom have had many years of experience studying the geology of mineral deposits, and more particularly the commodities about which they have written here. A total of nearly 2,300 man-years of professional experience in the geology of mineral resources is represented by the authors of the volume, and about 30 man-years went directly into its preparation. Each chapter contains not only a synthesis of the state of knowledge of the geology of the commodity, but also an appraisal of the known resources, and an examination of the geologic possibilities for finding additional deposits. In January 1972, responsibility for the preparation of the volume was assigned to us as co-editors, and we were given a tentative list of commodities and authors. We provided each author with a suggested outline of general topics to be covered, and some guidelines as to scope and philosophy of approach, but beyond that we avoided any attempt to fit each chapter into a stereotype. Moreover, the types of commodities range from the major metals and industrial minerals such as copper, silver, and fluorspar, which have been the subject of geologic research for years, to other commodities that are of such varied geologic nature (such as pigments or gemstones) or of such minor present importance (such as scandium or thallium) that they cannot be treated from the same viewpoint as the major minerals. The chapters range, therefore, from comprehensive summary reports to general essays that reflect the individuality of the authors as well as the variation among commodities. Throughout the book the emphasis is on geology, but each chapter contains some summary information on uses, technology, and economics. These summaries are not meant to be exhaustive, however, and additional details are in the 1970 edition of "Mineral Facts and Problems" (Bulletin

  18. Refining mineral oils

    Energy Technology Data Exchange (ETDEWEB)

    1946-07-05

    A process is described refining raw oils such as mineral oils, shale oils, tar, their fractions and derivatives, by extraction with a selected solvent or a mixture of solvents containing water, forming a solvent more favorable for the hydrocarbons poor in hydrogen than for hydrocarbons rich in hydrogen, this process is characterized by the addition of an aiding solvent for the water which can be mixed or dissolved in the water and the solvent or in the dissolving mixture and increasing in this way the solubility of the water in the solvent or the dissolving mixture.

  19. RELATIVE TRACE MINERAL BIOAVAILABILITY

    OpenAIRE

    Rchard D. Miles; Peter R. Henry

    2006-01-01

    Para determinar a eficiência de utilização de elementos minerais dietéticos, deve-se conhecer a biodisponibilidade relativa de cada elemento de um determinado ingrediente ou de uma ração completa. Análises químicas da dieta ou de um determinado ingrediente não indicam a efetividade biológica de um nutriente. Existem muitos fatores que influenciam a biodisponibilidade dos minerais, especialmente dos minerais-traço, tais como: nível de consumo do mineral, forma química, digestibilidade da dieta...

  20. A magnetic survey of mineral resources in northeastern Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Batista Rodriguez, Jose Alberto [Instituto Superior Minero Metalurgico de Moa (Cuba)

    2006-01-15

    Interpretation of the aeromagnetic survey of northeastern Cuba at scale 1 50 000 is presented. Mainly ophiolitic rocks are characterized by a high magnetic response. The aeromagnetic data was reduced to the pole and the horizontal and vertical gradients, as well as the upward continuation were calculated. To define areas of serpentinized ultrabasic rocks at surface and depth, the magnetic field transformations were interpreted. We discuss lateral extension of outcrops, thickness variation of the ophiolitic rocks, basement extension and fault zones. Hydrothermal alterations indicate associated precious metal secondary mineralization. Operations are planned to limit damage to mining by siliceous material in Fe+Ni laterites. [Spanish] Cuba, en la cual afloran fundamentalmente rocas ofioliticas caracterizadas por un alto grado de magnetizacion. Los datos aeromagneticos fueron reducidos al polo y luego se realizaron los calculos de gradientes horizontales y verticales y la continuacion analitica ascendente. A partir de los resultados de estas transformaciones se delimitaron zonas donde predominan las rocas ultrabasicas serpentinizadas tanto en superficie como en profundidad, definiendose la extension lateral de estas rocas por debajo de las rocas que afloran en superficie. Tambien se estimaron las variaciones de los espesores de las rocas ofioliticas, el basamento de las rocas que afloran, la presencia de estructuras disyuntivas, y se proponen nuevas estructuras de este tipo. Por ultimo se delimitan las zonas de alteracion hidrotermal, lo cual posee gran importancia, ya que con las mismas se pueden vincular mineralizaciones de metales preciosos. Ademas, su delimitacion en depositos lateriticos permite orientar los trabajos de explotacion minera, teniendo en cuenta el dano que causa al proceso metalurgico la presencia de material silicio en las lateritas Fe+Ni.