Sample records for abundant clay minerals

  1. The Clay Minerals Society

    NSDL National Science Digital Library

    "The Clay Minerals Society (CMS) is an international community of scientists who promote research in and disseminate information on clay science and technology." The website provides downloads of materials dealing with various aspects of mineralogy, geochemistry, and petrology. Researchers can find out about annual meetings, awards and grants, and publications. Students and educators can find information on teaching materials, clay science workshops, and games. The website offers physical and chemical data for Source and Special Clays.

  2. Lipid Peroxidation Induced by Expandable Clay Minerals

    E-print Network

    Ahmad, Sajjad

    Lipid Peroxidation Induced by Expandable Clay Minerals D A R I A K I B A N O V A , A N T O N I O N and toxicity. Herein, potential hazards of clay particle uptake areaddressed.Thispaperreportsthatthecontentanddistribution of structural Fe influence the ability of expandable clay minerals to induce lipid peroxidation (LP), a major

  3. Clay Minerals and Italy the Nannobacterial

    E-print Network

    Yang, Zong-Liang

    Clay Minerals and Italy ­ the Nannobacterial Connection R. L. FOLK THE UNIVERSITY OF TEXAS AT AUSTIN This work is dedicated to F. Leo Lynch, a brilliant clay mineralogist who died in 2009. During Leo of nannobacterial precipitation of clay minerals were identified. (Lynch, 1994; Folk, Lynch & Rasbury, 1994). Leo

  4. 2005 Minerals Yearbook CLAY AND SHALE

    E-print Network

    2005 Minerals Yearbook CLAY AND SHALE U.S. Department of the Interior U.S. Geological Survey February 2007 #12;CLAY AND SHALE--2005 18.1 CLAY AND SHALE By Robert L. Virta Domestic survey data. The amount of clay sold or used by domestic producers in 2005 was 41.7 million metric tons (Mt) valued at $1

  5. Dehydration-induced luminescence in clay minerals

    NASA Technical Reports Server (NTRS)

    Coyne, L. M.; Lahav, N.; Lawless, J. G.

    1981-01-01

    Reports of triboluminescent phenomena in organic crystalline materials prompted a search for related processes in clay minerals. The reported extensive mechanical distortion produced on freezing and drying of montmorillonite was particularly interesting because of studies of condensation reactions in a wet/dry cycled reaction sequence. The discovery of an unusual luminescent process in several clay minerals is reported and its characteristics are described.

  6. Geochemistry and halmyrolysis of clay minerals, Rio Ameca, Mexico

    Microsoft Academic Search

    Kenneth L. Russell

    1970-01-01

    Clay minerals from the Rio Ameca, Mexico, were vised for a study of the chemical interactions between clay minerals and sea water. Montmorillonite and kaolinite\\/halloysite are the common clay minerals with some amorphous material and illite also present. Clay minerals from the shallow portions of the bay near the river mouth seem to be only detrital material with no visible

  7. Clay Minerals are controlled by the environment - Clay Minerals control the environment

    NASA Astrophysics Data System (ADS)

    Stahr, K.; Zarei, M.

    2012-04-01

    Where clay minerals are analyzed in soils, often there is some confusion, because in the widespread loess-affected and moraine landscapes of Europe quite a variety of clay minerals is found. The sources of these minerals are inherited from the local solid rock, transported through different processes, transformed through mineral changes and inherited from paleo-environments. Very often a miserable assemblage in the clay fraction is found with mica clay, smectite, kaolinite, chlorite and also some quartz. In order to understand the current dynamic of clay mineral formation, very detailed and quantitative analysis in comparison of horizons and landscape are necessary. It is much easier to through light on the development, if conditions are looked for where a single specific mineral can be formed like short range order minerals from volcanic ashes or smectites from basaltic parent material. Old leaching land surfaces will form kaolinitic and in tropical areas gibbsitic clay fractions. In arid environments of deserts and desert fringes, palygorskite and sepiolite can dominate. In general, clay minerals buffer the environment. This is mainly due to the extraordinary large interfaces between mineral surface and pore systems. In the last years mainly the processes of buffering through charging soil solution and of buffering through mineral organic compounds have been analyzed. Development of new microscopic and spectromethods have brought great progress in understanding the role of clays in soil environments.

  8. ORIGINS OF CLAY MINERALS IN THE MOLYCORP MINE GOATHILL NORTH ROCK PILE, QUESTA, NM

    Microsoft Academic Search

    K. Donahue; N. Dunbar; V. McLemore

    There are three principle lines of evidence that indicate the clay minerals found in the Goathill North (GHN) rock pile at the Molycorp mine are predominantly a product of hydrothermal alteration, not weathering. The unweathered drill core and samples from GHN have similar types and abundances of clay-mineral groups based on XRD analysis. Chemical analyses from the electron microprobe reveal

  9. Ostwald ripening of clays and metamorphic minerals

    USGS Publications Warehouse

    Eberl, D.D.; Srodon, J.; Kralik, M.; Taylor, B.E.; Peterman, Z.E.

    1990-01-01

    Analyses of particle size distributions indicate that clay minerals and other diagenetic and metamorphic minerals commonly undergo recrystallization by Ostwald ripening. The shapes of their particle size distributions can yield the rate law for this process. One consequence of Ostwald ripening is that a record of the recrystallization process is preserved in the various particle sizes. Therefore, one can determine the detailed geologic history of clays and other recrystallized minerals by separating, from a single sample, the various particle sizes for independent chemical, structural, and isotopic analyses.

  10. Metachromasy in clay mineral systems

    Microsoft Academic Search

    C. Dobrogowska; L. G. Hepler; D. K. Ghosh; Sh. Yariv

    1991-01-01

    Adsorption of the metachromic (colour depends on concentration) cationic dyes crystal violet (CV) and ethyl violet (EV) by Na-kaolinite and Na-montmorillonite has been studied by visible spectroscopy and titration calorimetry. In the kaolinite system, metachromasy stems from association of the dye cations on the external surface of the clay. Enthalpies of adsorption at small dye\\/clay ratios are ?3.5 and ?3.8

  11. Clay minerals in the Meuse -Haute Marne underground laboratory (France): Possible influence of organic matter on clay mineral evolution

    E-print Network

    Paris-Sud XI, Université de

    Clay minerals in the Meuse - Haute Marne underground laboratory (France): Possible influence of organic matter on clay mineral evolution Francis Claret1,2,* , Boris A. Sakharov3 , Victor A. Drits3 words: Callovo-Oxfordian, Clay minerals, Clay diagenesis, Illite-smectite, Mixed- layering

  12. Clays and other minerals in prebiotic processes

    NASA Technical Reports Server (NTRS)

    Paecht-Horowitz, M.

    1984-01-01

    Clays and other minerals have been investigated in context with prebiotic processes, mainly in polymerization of amino acids. It was found that peptides adsorbed on the clay, prior to polymerization, influence the reaction. The ratio between the amount of the peptides adsorbed and that of the clay is important for the yield as well as for the degrees of polymerization obtained. Adsorption prior to reaction produces a certain order in the aggregates of the clay particles which might induce better reaction results. Excess of added peptides disturbs this order and causes lesser degrees of polymerization. In addition to adsorption, clays are also able to occlude between their layers substances out of the environment, up to very high concentrations.

  13. The Link between Clay Mineral Weathering and the Stabilization of

    E-print Network

    Sparks, Donald L.

    The Link between Clay Mineral Weathering and the Stabilization of Ni Surface Precipitates R O B E R 19717 The formation of transition-metal surface precipitates may occur during sorption to clay minerals formation are poorly understood. We monitored changes in the reversibility of Ni sorbed to a clay mineral

  14. Black Carbon, The Pyrogenic Clay Mineral?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most soils contain significant amounts of black carbon, much of which is present as discrete particles admixed with the coarse clay fraction (0.2–2.0 µm e.s.d.) and can be physically separated from the more abundant diffuse biogenic humic materials. Recent evidence has shown that naturally occurring...

  15. Radiation-induced defects in clay minerals: A review

    NASA Astrophysics Data System (ADS)

    Allard, Th.; Balan, E.; Calas, G.; Fourdrin, C.; Morichon, E.; Sorieul, S.

    2012-04-01

    Extensive information has been collected on radiation effects on clay minerals over the last 35 years, providing a wealth of information on environmental and geological processes. The fields of applications include the reconstruction of past radioelement migrations, the dating of clay minerals or the evolution of the physico-chemical properties under irradiation. The investigation of several clay minerals, namely kaolinite, dickite, montmorillonite, illite and sudoite, by Electron Paramagnetic Resonance Spectroscopy has shown the presence of defects produced by natural or artificial radiations. These defects consist mostly of electron holes located on oxygen atoms of the structure. The various radiation-induced defects are differentiated through their nature and their thermal stability. Most of them are associated with a ? orbital on a Si-O bond. The most abundant defect in clay minerals is oriented perpendicular to the silicate layer. Thermal annealing indicates this defect in kaolinite (A-center) to be stable over geological periods at ambient temperature. Besides, electron or heavy ion irradiation easily leads to an amorphization in smectites, depending on the type of interlayer cation. The amorphization dose exhibits a bell-shaped variation as a function of temperature, with a decreasing part that indicates the influence of thermal dehydroxylation. Two main applications of the knowledge of radiation-induced defects in clay minerals are derived: (i) The use of defects as tracers of past radioactivity. In geological systems where the age of the clay can be constrained, ancient migrations of radioelements can be reconstructed in natural analogues of high level nuclear waste repositories. When the dose rate may be assumed constant over time, the paleodose is used to date clay populations, an approach applied to fault gouges or laterites of the Amazon basin. (ii) The influence of irradiation over physico-chemical properties of clay minerals. An environmental application concerns the performance assessment of the engineered barrier of nuclear waste disposals. In case of a leakage of transuranic elements from the radioactive waste form, alpha recoil nuclei can amorphize smectite after periods of the order of 1000 years according to a worst case scenario, whereas amorphization from ionizing radiation is unlikely. As amorphization greatly enhances the dissolution kinetics of smectite, the sensitivity of the smectites must be taken into account in the prediction of the long term behavior of engineered barriers.

  16. Feasibility of classification of clay minerals by using PAS

    NASA Astrophysics Data System (ADS)

    Honda, Y.; Yoshida, Y.; Akiyama, Y.; Nishijima, S.

    2015-06-01

    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.

  17. Sorption Energy Maps of Clay Mineral Surfaces

    SciTech Connect

    Cygan, Randall T.; Kirkpatrick, R. James

    1999-07-19

    A molecular-level understanding of mineral-water interactions is critical for the evaluation and prediction of the sorption properties of clay minerals that may be used in various chemical and radioactive waste disposal methods. Molecular models of metal sorption incorporate empirical energy force fields, based on molecular orbital calculations and spectroscopic data, that account for Coulombic, van der Waals attractive, and short-range repulsive energies. The summation of the non-bonded energy terms at equally-spaced grid points surrounding a mineral substrate provides a three dimensional potential energy grid. The energy map can be used to determine the optimal sorption sites of metal ions on the exposed surfaces of the mineral. By using this approach, we have evaluated the crystallographic and compositional control of metal sorption on the surfaces of kaolinite and illite. Estimates of the relative sorption energy and most stable sorption sites are derived based on a rigid ion approximation.

  18. 2006 Minerals Yearbook ClaY and Shale

    E-print Network

    2006 Minerals Yearbook ClaY and Shale U.S. Department of the Interior U.S. Geological Survey January 2008 #12;Clay and Shale--2006 18.1 The amount of clay sold or used by domestic producers in 2006 in 2005 (table 1). Common clay and shale accounted for 59% of the tonnage, and kaolin accounted for 55

  19. Diagenetic clays as pore-lining minerals in coalbed methane reservoirs

    SciTech Connect

    Fowler, K.S.; Nick, K.E. [STIM-LAB, Inc., Duncan, OK (United States)

    1996-12-31

    Cleat surfaces from Mary Lee and Black Creek coal seams in the Black Warrior Basin and Fruitland coal from the San Juan Basin show significant amounts of diagenetic quartz, illite, kaolinite, carbonate minerals, barite, gypsum and iron sulfides and sulfates. SEM, XRD, thin section and reflected light microscopy analyses were used to identify and describe diagenetic minerals and surface textures observed along permeable cleat surfaces. SEM-EDS analysis reveals a variety of pore-lining diagenetic minerals with complex crystal morphologies in permeable cleats of preserved core and mine samples. Surface textures were varied from smooth and vitreous, dull and pitted, to rough and irregular with imbedded diagenetic minerals, often clays or sulfides. Illite is the most abundant clay and occurs as surface coatings, aggregates, authigenic crystals embedded in the coal surface, or oriented subparallel to the fracture face. Kaolinite is also abundant and occurs as abraded platelets and loosely attached aggregates packed against steps, as meniscus shapes on smooth fracture faces, and as a thick crust of anhedral crystals. Chlorite, the least abundant clay, appears as sheets of small crystals. Locally abundant sulfate, sulfide and carbonate minerals are present in masses of euhedral crystals or concentrated as thick crusts. Surface irregularities sometimes control the distribution of diagenetic minerals. Coal fines of unambiguous internal origin and masses of clays are often concentrated at surface irregularities such as steps, laminations of interbedded clays, or sulfides and coal and rough areas of fractures. Their distribution suggests mobility within fractures.

  20. Diagenetic clays as pore-lining minerals in coalbed methane reservoirs

    SciTech Connect

    Fowler, K.S.; Nick, K.E. (STIM-LAB, Inc., Duncan, OK (United States))

    1996-01-01

    Cleat surfaces from Mary Lee and Black Creek coal seams in the Black Warrior Basin and Fruitland coal from the San Juan Basin show significant amounts of diagenetic quartz, illite, kaolinite, carbonate minerals, barite, gypsum and iron sulfides and sulfates. SEM, XRD, thin section and reflected light microscopy analyses were used to identify and describe diagenetic minerals and surface textures observed along permeable cleat surfaces. SEM-EDS analysis reveals a variety of pore-lining diagenetic minerals with complex crystal morphologies in permeable cleats of preserved core and mine samples. Surface textures were varied from smooth and vitreous, dull and pitted, to rough and irregular with imbedded diagenetic minerals, often clays or sulfides. Illite is the most abundant clay and occurs as surface coatings, aggregates, authigenic crystals embedded in the coal surface, or oriented subparallel to the fracture face. Kaolinite is also abundant and occurs as abraded platelets and loosely attached aggregates packed against steps, as meniscus shapes on smooth fracture faces, and as a thick crust of anhedral crystals. Chlorite, the least abundant clay, appears as sheets of small crystals. Locally abundant sulfate, sulfide and carbonate minerals are present in masses of euhedral crystals or concentrated as thick crusts. Surface irregularities sometimes control the distribution of diagenetic minerals. Coal fines of unambiguous internal origin and masses of clays are often concentrated at surface irregularities such as steps, laminations of interbedded clays, or sulfides and coal and rough areas of fractures. Their distribution suggests mobility within fractures.

  1. Prolonged triboluminescence in clays and other minerals

    NASA Technical Reports Server (NTRS)

    Lahav, N.; Coyne, L. M.; Lawless, J. G.

    1982-01-01

    Samples of various clays and minerals were ground or fractured and monitored with a liquid scintillation spectrometer in order to obtain triboluminescent decay curves. Kaolinite samples displayed several million counts/min after grinding, with a surface area emission estimated at tens of billions of photons/sq cm of surface. The photon production rates varied with the origin of the sample, and kaolinite continually yielded higher production rates than bentonite. The addition of water to the samples slightly increased the count rate of emitted light, while the addition of the fluorescent molecule substance tryptofan significantly enhanced the count rate. Freezing smears of kaolinite and montmorillonite in liquid nitrogen and in a salt ice mixture also induced triboluminescence in the montmorillonite. A possible connection between powdery triboluminescent materials formed in mining industries and respiratory disorders among miners is suggested.

  2. Implications of abundant hygroscopic minerals in the Martian regolith

    NASA Technical Reports Server (NTRS)

    Clark, B. C.

    1978-01-01

    Converging lines of evidence suggest that a significant portion of the Martian surface fines may consist of salts and smectite clays. Salts can form stoichiometric hydrates as well as eutectic solutions with depressed freezing points; clays contain bound water of constitution and adsorb significant quantities of water from the vapor phase. The formation of ice may be suppressed by these minerals in some regions on Mars, and their presence in abundance would imply important consequences for atmospheric and geologic processes and the prospects for exobiology.

  3. Analysis of mixed-layer clay mineral structures

    USGS Publications Warehouse

    Bradley, W.F.

    1953-01-01

    Among the enormously abundant natural occurrences of clay minerals, many examples are encountered in which no single specific crystallization scheme extends through a single ultimate grain. The characterization of such assemblages becomes an analysis of the distribution of matter within such grains, rather than the simple identification of mineral species. It having become established that the particular coordination complex typified by mica is a common component of many natural subcrystalline assemblages, the opportunity is afforded to analyze scattering from random associations of these complexes with other structural units. Successful analyses have been made of mixed hydration states of montmorillonite, of montmorillonite with mica, of vermiculite with mica, and of montmorillonite with chlorite, all of which are variants of the mica complex, and of halloysite with hydrated halloysite.

  4. Layer Charge of Clay Minerals; Selected papers from the Symposium on Current Knowledge on the Layer Charge of Clay Minerals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This Special issue contains papers based on the contributions presented during the workshop “Current Knowledge on the Layer Charge of Clay Minerals”, held on September 18 and 19, 2004, in the Smolenice Castle, Slovakia. Layer charge is one of the most important characteristics of clay minerals as it...

  5. Clay mineral formation and transformation in rocks and soils

    USGS Publications Warehouse

    Eberl, D.D.

    1983-01-01

    Three mechanisms for clay mineral formation (inheritance, neoformation, and transformation) operating in three geological environments (weathering, sedimentary, and diagenetic-hydrothermal) yield nine possibilities for the origin of clay minerals in nature. Several of these possibilities are discussed in terms of the rock cycle. The mineralogy of clays neoformed in the weathering environment is a function of solution chemistry, with the most dilute solutions favoring formation of the least soluble clays. After erosion and transportation, these clays may be deposited on the ocean floor in a lateral sequence that depends on floccule size. Clays undergo little reaction in the ocean, except for ion exchange and the neoformation of smectite; therefore, most clays found on the ocean floor are inherited from adjacent continents. Upon burial and heating, however, dioctahedral smectite reacts in the diagenetic environment to yield mixed-layer illite-smectite, and finally illite. With uplift and weathering, the cycle begins again. Refs.

  6. Introduction to the properties of clay minerals

    NSDL National Science Digital Library

    stephen Guggenheim

    This activity explores how clay affects the permeability of sands, the effect of chemical differences of the clay (cation exchange), and how these results may be applied to low-level radioactive waste disposal sites.

  7. Toxicological evaluation of clay minerals and derived nanocomposites: a review.

    PubMed

    Maisanaba, Sara; Pichardo, Silvia; Puerto, María; Gutiérrez-Praena, Daniel; Cameán, Ana M; Jos, Angeles

    2015-04-01

    Clays and clay minerals are widely used in many facets of our society. This review addresses the main clays of each phyllosilicate groups, namely, kaolinite, montmorillonite (Mt) and sepiolite, placing special emphasis on Mt and kaolinite, which are the clays that are more frequently used in food packaging, one of the applications that are currently exhibiting higher development. The improvements in the composite materials obtained from clays and polymeric matrices are remarkable and well known, but the potential toxicological effects of unmodified or modified clay minerals and derived nanocomposites are currently being investigated with increased interest. In this sense, this work focused on a review of the published reports related to the analysis of the toxicological profile of commercial and novel modified clays and derived nanocomposites. An exhaustive review of the main in vitro and in vivo toxicological studies, antimicrobial activity assessments, and the human and environmental impacts of clays and derived nanocomposites was performed. From the analysis of the scientific literature different conclusions can be derived. Thus, in vitro studies suggest that clays in general induce cytotoxicity (with dependence on the clay, concentration, experimental system, etc.) with different underlying mechanisms such as necrosis/apoptosis, oxidative stress or genotoxicity. However, most of in vivo experiments performed in rodents showed no clear evidences of systemic toxicity even at doses of 5000mg/kg. Regarding to humans, pulmonary exposure is the most frequent, and although clays are usually mixed with other minerals, they have been reported to induce pneumoconiosis per se. Oral exposure is also common both intentionally and unintentionally. Although they do not show a high toxicity through this pathway, toxic effects could be induced due to the increased or reduced exposure to mineral elements. Finally, there are few studies about the effects of clay minerals on wildlife, with laboratory trials showing contradictory outcomes. Clay minerals have different applications in the environment, thus with a strict control of the concentrations used, they can provide beneficial uses. Despite the extensive number of reports available, there is also a need of systematic in vitro-in vivo extrapolation studies, with still scarce information on toxicity biomarkers such as inmunomodulatory effects or alteration of the genetic expression. In conclusion, a case by case toxicological evaluation is required taking into account that different clays have their own toxicological profiles, their modification can change this profile, and the potential increase of the human/environmental exposure to clay minerals due to their novel applications. PMID:25732897

  8. Immersion freezing of clay minerals and bacterial ice nuclei

    E-print Network

    Hiranuma, Naruki

    2013-01-01

    The immersion mode ice nucleation efficiency of clay minerals and biological aerosols has been investigated using the AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud chamber. Both monodisperse and polydisperse ...

  9. Clay Mineral Assemblages as Proxies for Reconstructing Messinian Paleoenvironments in the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Martinez-Ruiz, Francisca; Comas, Menchu; Vasconcelos, Crisogono

    2014-05-01

    Significant tectonic and climate changes at time of the Messinian Salinity Crisis (MSC) led to a complex sedimentation involving marked changes in sediment composition, particularly in clay mineral assemblages. One of the noticeable mineralogical changes across this time interval is the strong smectite increase in Messinian deposits in comparison to the underlying Tortonian and overlaying Pliocene sediments. As no break in the clay mineralogy is recognized in the open ocean (Chamley et al., 1978), such changes are also distinctive of the Mediterranean basins. Since the early discoveries of the giant Messinian evaporite formation (DSDP Legs 13 and 42A), a vast literature contributed, during the last decades, to the continuous debate and re-examination of the actual Messinian paleoenvironment. Drilled records in the westernmost Mediterranean (Alboran Sea) have shown significant changes in the mineralogical assemblages associated to the Messinian events. This basin is depleted of significant salt deposits. Site 976 (ODP Leg 161) recovered a 670-m-thick, middle Miocene (Serravallian) to Pleistocene/Holocene sedimentary sequence, including a thin interval of Messinian sediment, lying directly upon the metamorphic basement. Analysis of clay mineral assemblages from the sedimentary cover of Hole 976B revealed an homogeneous clay association composed of illite, smectite, chlorite and kaolinite with no major changes in clay mineral abundances except for the sediment interval dated as Messinian, which is characterized by a sharp smectite increase (Martinez-Ruiz et al., 1999). Transmission Electron Microscope analyses of clay minerals revealed that smectite composition corresponds to Al-rich beidellites, which supports the existence of such smectites in peri-Mediterranean soils. Smectite formation was favored by the climate conditions at that time, comprising progressive aridification and the alternation of wet and dry climatic episodes. Diagenesis in these smectites is negligible, further evidencing a detrital origin. However, a closer look at clay mineral associations provides an alternate understanding of clay mineral origin, including the possibility of smectite authigenesis in a Mg-rich paleoenvironment. Furthermore, fibrous clays could have originated in such environments. Relationships between Mg-rich clays and carbonates in Messinian sediments should be a next step to explore further constraints on depositional conditions. Chamley, H., Dunoyer-de-Segonzac, G., & Melieres, F. (1978). Clay minerals in Messinian sediments of the Mediterranean Sea. Initial Reports of the Deep Sea Drilling Project, Vol. 42, Part 1, pp. 389-395. Martinez-Ruiz, F., Comas, M. C., & Alonso, B. (1999). Mineral associations and geochemical indicators in Upper Miocene to Pleistocene sediments in the Alboran Basin. In: Proceedings of the Ocean Drilling Program, Scientific Reports, Vol. 161, pp. 21-37.

  10. Diagenesis of clay minerals from early Eocene shales of Texas 

    E-print Network

    Whynot, John David

    1983-01-01

    -ra Diffraction A semiquantitative estimate of the quartz, feldspar and total clay in the silt and coarse clay fraction of each sample was made from X-ray diffractograms of randomly oriented samples using Schultz's (1964) method (Appendix 1). Schultz's (1964...) method was also used 14 to obtain estimates of the clay minerals in the coarse and fine clay size fractions from diffractograms of Mg-glycerated, and K saturated samples heated to 300'C (Appendix 1). Schultz (1964) reported that this method gives a...

  11. Differentiation of pleistocene deposits in northeastern Kansas by clay minerals

    USGS Publications Warehouse

    Tien, P.-L.

    1968-01-01

    Seventy-four samples from eight stratigraphic sections of lower Pleistocene glacial and glaciofluvial deposits in Doniphan County, extreme northeastern Kansas, were analyzed using X-ray diffraction techniques. Clay-mineral assemblages of the <2 ?? fraction of these deposits are nearly identical, consisting of a mixed-layer clay mineral associated with minor amounts of kaolinite and illite. An attempt was made to differentiate units of till and nontill deposits by using the relative intensities of 001 reflections of "mixed-layer mineral," kaolinite, and illite. At least two tills were recognizable. Associated nontill deposits, could not be differentiated from one another, although the nontills are easily distinguished from tills. ?? 1968.

  12. Adsorption coefficients for TNT on soil and clay minerals

    NASA Astrophysics Data System (ADS)

    Rivera, Rosángela; Pabón, Julissa; Pérez, Omarie; Muñoz, Miguel A.; Mina, Nairmen

    2007-04-01

    To understand the fate and transport mechanisms of TNT from buried landmines is it essential to determine the adsorption process of TNT on soil and clay minerals. In this research, soil samples from horizons Ap and A from Jobos Series at Isabela, Puerto Rico were studied. The clay fractions were separated from the other soil components by centrifugation. Using the hydrometer method the particle size distribution for the soil horizons was obtained. Physical and chemical characterization studies such as cation exchange capacity (CEC), surface area, percent of organic matter and pH were performed for the soil and clay samples. A complete mineralogical characterization of clay fractions using X-ray diffraction analysis reveals the presence of kaolinite, goethite, hematite, gibbsite and quartz. In order to obtain adsorption coefficients (K d values) for the TNT-soil and TNT-clay interactions high performance liquid chromatography (HPLC) was used. The adsorption process for TNT-soil was described by the Langmuir model. A higher adsorption was observed in the Ap horizon. The Freundlich model described the adsorption process for TNT-clay interactions. The affinity and relative adsorption capacity of the clay for TNT were higher in the A horizon. These results suggest that adsorption by soil organic matter predominates over adsorption on clay minerals when significant soil organic matter content is present. It was found that, properties like cation exchange capacity and surface area are important factors in the adsorption of clayey soils.

  13. Intercalation of Trichloroethene by Sediment-Associated Clay Minerals

    SciTech Connect

    Matthieu, Donald E.; Brusseau, Mark; Johnson, G. R.; Artiola, J. L.; Bowden, Mark E.; Curry, J. E.

    2013-01-01

    The objective of this research was to examine the potential for intercalation of trichloroethene (TCE) by clay minerals associated with aquifer sediments. Sediment samples were collected from a field site inTucson, AZ. Two widely used Montmorillonite specimen clays were employed as controls. X-ray diffraction, conducted with a controlled-environment chamber, was used to characterize smectite interlayer dspacing for three treatments (bulk air-dry sample, sample mixed with synthetic groundwater, sample mixed with TCE-saturated synthetic groundwater). The results show that the d-spacing measured for the samples treated with TCE-saturated synthetic groundwater are larger (*26%) than those of the untreated samples for all field samples as well as the specimen clays. These results indicate that TCE was intercalated by the clay minerals, which may have contributed to the extensive elution tailing observed in prior miscible-displacement experiments conducted with this sediment.

  14. INTERCALATION OF TRICHLOROETHENE BY SEDIMENT-ASSOCIATED CLAY MINERALS

    PubMed Central

    Matthieu, D.E.; Brusseau, M.L.; Johnson, G.R.; Artiola, J.L.; Bowden, M.L.; Curry, J.E.

    2012-01-01

    The objective of this research was to examine the potential for intercalation of trichloroethene (TCE) by clay minerals associated with aquifer sediments. Sediment samples were collected from a field site in Tucson, AZ. Two widely used Montmorillonite specimen clays were employed as controls. X-ray diffraction, conducted with a controlled-environment chamber, was used to characterize smectite interlayer d-spacing for three treatments (bulk air-dry sample, sample mixed with synthetic groundwater, sample mixed with TCE-saturated synthetic groundwater). The results show that the d-spacing measured for the samples treated with TCE-saturated synthetic groundwater are larger (~26%) than those of the untreated samples for all field samples as well as the specimen clays. These results indicate that TCE was intercalated by the clay minerals, which may have contributed to the extensive elution tailing observed in prior miscible-displacement experiments conducted with this sediment. PMID:22921434

  15. Environmental applications of radiation-induced defects in clay minerals

    NASA Astrophysics Data System (ADS)

    Allard, T.

    2011-12-01

    Radiation effects on clay minerals have been studied over the last 35 years, providing a wealth of information on environmental and geological processes. They have been applied to the reconstruction of past radioelement migrations in the geosphere, the dating of clay minerals from soils or the evolution of the physico-chemical properties under irradiation. All known radiation-induced point defects in clay minerals are detected using Electron Paramagnetic Resonance Spectroscopy. They mostly consist in electron holes located on oxygen atoms of the structure, and can be differentiated through their nature and their thermal stability. For instance, several are associated to a ? orbital on a Si-O bond. One defect, namely the A-center, is stable over geological periods at ambiant temperature. These point defects are produced mainly by ionizing radiations. By contrast to point defects, it was shown that electron or heavy ion irradiation easily produces amorphization in smectites. Two main applications of radiation-induced defects in clay minerals are derived : (i) the use of defects as tracers of past radioactivity. In geosystems where the age of the clay can be constrained, migrations of radioelements can be reconstructed in natural analogues of the far field of high level nuclear waste repositories. When the dose rate may be assumed constant over time, the paleodose is used to date clay populations, an approach applied to laterites of the Amazon basin. (ii) The influence of radiation on clay mineral properties that remains poorly documented, although it is an important issue in various domains such as the safety assessment of the high level nuclear waste repositories. In case of a leakage of transuranic elements from the radioactive wasteform, alpha recoil nuclei would amorphize smectite after a period much lower than the disposal lifetime. By contrast, amorphisation from ionizing radiation is unlikely over 1 million years. Furthermore, it was shown that amorphization greatly enhances the dissolution kinetics of smectite, a result that must be taken into account in the safety assessment of engineered barriers.

  16. Immersion Freezing of Clay Minerals and its Time Dependence

    NASA Astrophysics Data System (ADS)

    Hiranuma, N.; Moehler, O.; Bundke, U.; Cziczo, D. J.; Danielczok, A.; Ebert, M.; Garimella, S.; Hoffmann, N.; Kanji, Z. A.; Kiselev, A. A.; Raddatz, M.; Stetzer, O.

    2012-12-01

    Immersion ice nucleation efficiency of clay minerals has been investigated using the AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud chamber. Various clay dust samples, including two illite as well as three kaolinite standards, have been examined in the temperature range between 238 K and 255 K. We observed two trends in immersion ice nucleation properties as cloud expansion conditions in the AIDA are varied. First, as previously described in the literature, the supersaturation required for the immersion freezing of clay minerals decreased with decreasing temperature and increasing inferred ice-active surface site densities. Second, the ice nucleation activity of clay minerals strongly depended on the solo-parameter, which is the rate change in temperature (i.e., dNice/dT = ?Nice/?t ÷ ?T/?t). Further time dependence of ice formation is investigated and discussed as a function of cooling rates, ice nuclei (IN), and aerosol concentrations. Ice residuals collected through a pumped counterflow virtual impactor are examined by electron microprobe analyses to seek the true chemical and physical identity of IN in clay minerals. Brief comparisons of AIDA measurement to the measurements with other ice nucleation chambers (e.g., ETH-PINC, FINCH, and commercially available DMT-SPIN) are also presented.

  17. First Direct Detection of Clay Minerals on Mars

    NASA Technical Reports Server (NTRS)

    Singer, R. B.; Owensby, P. D.; Clark, R. N.

    1985-01-01

    Magnesian clays or clay-type minerals were conclusively detected in the martian regolith. Near-IR spectral observations of Mars using the Mauna Kea 2.2-m telescope show weak but definite absorption bands near microns. The absorption band positions and widths match those produced by combined OH stretch and Mg-OH lattice modes and are diagnostic of minerals with structural OH such as clays and amphiboles. Likely candidate minerals include serpentine, talc, hectorite, and sponite. There is no spectral evidence for aluminous hydroxylated minerals. No distinct band occurs at 2.55 microns, as would be expected if carbonates were responsible for the 2.35 micron absorption. High-albedo regions such as Elysium and Utopia have the strongest bands near 2.35 microns, as would be expected for heavily weathered soils. Low-albedo regions such as Iapygia show weaker but distinct bands, consistent with moderate coatings, streaks, and splotches of bright weathered material. In all areas observed, the 2.35-micron absorption is at least three times weaker than would be expected if well-crystallized clay minerals made up the bulk of bright soils on Mars.

  18. Iodide interactions with clay minerals: Batch and diffusion studies

    NASA Astrophysics Data System (ADS)

    Miller, A. W.; Kruichak, J.; Mills, M.; Wang, Y.

    2012-12-01

    Clay minerals are likely candidates to aid in nuclear waste isolation due to their low permeability, favorable swelling properties, and high cation sorption capacities. Iodine-129 is often the major driver of exposure risk from nuclear waste repositories at timescales >10,000 years. Therefore, understanding the geochemical cycling of iodine in clays is critical in developing defensible quantitative descriptions of nuclear waste disposal. Anions are not typically considered to interact with most clays as it is assumed that the fixed negative charge of clays actively repels the dissoloved anion. This is corroborated by many batch studies, but diffusion experiments in compacted clays have shown iodide retardation relative to chloride. The reasons for this are unknown; however, several possible hypotheses include: redox transformation controls on sorption behavior, complex surface charge environments due to overlapping charge domains, and sorption to ancillary minerals or weathering products. Seven different clay minerals have been examined using several techniques to chracterize the surface charge environment and iodide uptake. The use of a series of clays shifts the independent variable away from water chemistry characteristics (pH, contaminant concentration), and toward structural characterisitics of clay minerals including isomorphous substitution and clay texture. Iodide uptake batch experiments were completed with the clay minerals in a range of swamping electrolytes. The results give evidence for a novel uptake mechanism involving ion pair formation and iodide concentration within nano-confined environments. These results were further tested using diffusional columns where nano-confined regimes make up a larger proportion of the total porosity. These columns were compacted to different hydrostatic pressures and saturated with different ionic compositions. Porosity distributions were characterized with a fluoride tracer. Iodide diffusion characteristics were found to be dependent on ionic composition and confining pressure. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corperation, for the U.S. Department of Energy's Nation Nuclear Security Administration under contract DE-AC04-94AL85000.

  19. Enchanted Clays: 44th Annual Meeting of the Clay Minerals Society (June 2007)

    SciTech Connect

    Randall T. Cygan

    2007-06-01

    “Enchanted Clays: 44th Annual Meeting of the Clay Minerals Society” was held in early June 2007 in beautiful and historic Santa Fe, New Mexico, USA. Santa Fe provided an idyllic location in the southwestern United States for the attendees to enjoy technical and social sessions while soaking up the diverse culture and wonderful climate of New Mexico—The Land of Enchantment. The meeting included a large and varied group of scientists, sharing knowledge and ideas, benefitting from technical interactions, and enjoying the wonderful historic and enchanted environs of Santa Fe. Including significant number of international scientists, the meeting was attended by approximately two hundred participants. The meeting included three days of technical sessions (oral and poster presentations), three days of field trips to clay and geological sites of northern New Mexico, and a full day workshop on the stabilization of carbon by clays. Details can be found at the meeting web site: www.sandia.gov/clay.

  20. Fibrous-clay mineral formation and soil evolution in Aridisols of northeastern Patagonia, Argentina

    E-print Network

    Ahmad, Sajjad

    Fibrous-clay mineral formation and soil evolution in Aridisols of northeastern Patagonia, Argentina Patagonia identified fibrous-clay minerals in calcic and petrocalcic horizons developed on old fluvio the occurrence of fibrous-clay minerals in the arid soil environment, and ii) to establish the relationship

  1. Clay minerals in late glacial and Holocene sediments of the northern and southern Aegean Sea

    E-print Network

    Siebel, Wolfgang

    Clay minerals in late glacial and Holocene sediments of the northern and southern Aegean Sea Werner Different source areas, oceanography and climate regimes influenced the clay mineral assemblages and grain and the Holocene. In the North Aegean Sea, clay mineral composition is mainly controlled by sea level evolution

  2. Physicochemical Controls on the Formation of Polynuclear Metal Complexes at Clay Mineral Surfaces

    E-print Network

    Sparks, Donald L.

    Physicochemical Controls on the Formation of Polynuclear Metal Complexes at Clay Mineral Surfaces R. G. Ford Metal sorption to clay minerals may lead to the formation of secondary precipitates, by enhanced dissolution of the clay mineral structure as indicated by enhanced levels of dissolved silica

  3. Geochemical study of evaporite and clay mineral-oxyhydroxide samples from the Waste Isolation Pilot Plant site

    SciTech Connect

    Brookins, D.G. [Univ. of New Mexico, Albuquerque, NM (US). Dept. of Geology

    1993-06-01

    Samples of clay minerals, insoluble oxyhydroxides, and their host evaporites from the WIPP site have been studied for their major and minor elements abundances, x-ray diffraction characteristics, K-Ar ages, and Rb-Sr ages. This study was undertaken to determine their overall geochemical characteristics and to investigate possible interactions between evaporates and insoluble constituents. The evaporite host material is water-soluble, having Cl/Br ratios typical of marine evaporites, although the Br content is low. Insoluble material (usually a mixture of clay minerals and oxyhydroxide phases) yields very high Cl/Br ratios, possibly because of Cl from admixed halide minerals. This same material yields K/Rb and Th/U ratios in the normal range for shales; suggesting little, if any, effect of evaporite-induced remobilization of U, K, or Rb in the insoluble material. The rare-earth element (REE) data also show normal REE/chondrite (REE/CHON) distribution patterns, supporting the K/Rb and Th/U data. Clay minerals yield K-Ar dates in the range 365 to 390 Ma and a Rb-Sr isochron age of 428 {+-} 7 Ma. These ages are well in excess of the 220- to 230-Ma formational age of the evaporites, and confirm the detrital origin of the clays. The ages also show that any evaporite or clay mineral reactions that might have occurred at or near the time of sedimentation and diagenesis were not sufficient to reset the K-Ar and Rb-Sr systematics of the clay minerals. Further, x-ray data indicate a normal evaporitic assemblage of clay minerals and Fe-rich oxyhydroxide phases. The clay minerals and other insoluble material appear to be resistant to the destructive effects of their entrapment in the evaporites, which suggests that these insoluble materials would be good getters for any radionuclides (hypothetically) released from the storage of radioactive wastes in the area.

  4. Potassium Fixation and Supply by Soils with Mixed Clay Minerals.

    E-print Network

    Hipp, Billy W.

    1969-01-01

    B-1090 December 1969 1 potassium Fixation and Supply By Soils With Misd Clay Minerals I KUS A&M UNIVERSITY Tcrv Agricultural Experiment Station r i 0. Kunkel, Acting Director, College Station, Texas Summary to the plants while Cameron clay... supplied onl!. Studies were made on three agriculturally important me/me of exchangeable K. The capacity of all a soils of South Texas and Northern Mexico to determine soils to fix K increased with increasing remo\\dl i their potassium (K)-supplying power...

  5. Water molecules in clay minerals: Thermodynamic functions and hydration

    NASA Astrophysics Data System (ADS)

    Gailhanou, Helène; Amouric, Marc; Olives, Juan; Rogez, Jacques; van Miltenburg, J. C.; van der Berg, G. J. K.; de Weireld, G.; Gaucher, E.; Blanc, P.

    2010-05-01

    Thermodynamic functions and adsorption of water molecules are very important properties for clay minerals. Smectite MX-80 and mixed-layer illite-smectite ISCz-1 were selected. They were first carefully characterized (HRTEM with EDX analysis), revealing original results. Then, the thermodynamic properties of water in clay were obtained by (i) comparison of the thermodynamic properties of anhydrous and hydrated minerals, between 0 and 350 K (adiabatic calorimetry, solution isothermal calorimetry), and (ii) water vapor adsorption isotherms, between 300 and 380 K (magnetic suspension thermobalance). Solution isothermal calorimetry is used to determine the enthalpies of formation of the minerals (1 bar and 298 K). Comparison of the results, for the anhydrous and the hydrated minerals, leads to the enthalpies of hydration at 298 K. Adiabatic calorimetry measurements give the heat capacities of the minerals from 5 to 350 K. Entropies, enthalpies of formation and Gibbs free energies of formation, for the anhydrous and the hydrated minerals, and then, entropies of hydration, enthalpies of hydration and Gibbs free energies of hydration, between 0 and 350 K, are finally obtained. Comparison of two close hydration states leads to the entropy, the enthalpy and the Gibbs free energy of the adsorption reaction: H2O free - H2O adsorbed. The Cp(T) curve, for the heat capacity of water in clay - i.e., the difference between the heat capacities of the hydrated and the anhydrous minerals -, shows that water in clay is a glass at low temperature, undergoes one or two continuous glass transitions between 150 and 270 K, and behaves as free liquid water above 273 K. The two glass transitions might correspond to two types of water molecules: (i) first adsorbed water molecules, bound to the interlayer cations of the clay mineral; (ii) last adsorbed water molecules, not bound to the interlayer cations. In addition, water vapor adsorption isotherms are obtained from 298 to 378 K (magnetic suspension thermobalance) and well fitted with a BET type model (with three layers of adsorbed water molecules). The Gibbs free energy of the adsorption reaction and the Gibbs free energy of hydration, for any hydration state, can be determined. They are in agreement with the above calorimetric values. Gailhanou H., van Miltenburg J.C., Rogez J., Olives J., Amouric M., Gaucher E.C., Blanc P. (2007).Thermodynamic properties of anhydrous smectite, illite and illite-smectite. (Part 1) Geochim Cosmochim. Acta 71, 5463-5473.

  6. CO2 adsorption isotherm on clay minerals and the CO2 accessibility into the clay interlayer

    NASA Astrophysics Data System (ADS)

    Gensterblum, Yves; Bertier, Pieter; Busch, Andreas; Rother, Gernot; Krooß, Bernhard

    2013-04-01

    Large-scale CO2 storage in porous rock formations at 1-3 km depth is seen as a global warming mitigation strategy. In this process, CO2 is separated from the flue gas of coal or gas power plants, compressed, and pumped into porous subsurface reservoirs with overlying caprocks (seals). Good seals are mechanically and chemically stable caprocks with low porosity and permeability. They prevent leakage of buoyant CO2 from the reservoir. Caprocks are generally comprised of thick layers of shale, and thus mainly consist of clay minerals. These clays can be affected by CO2-induced processes, such as swelling or dissolution. The interactions of CO2 with clay minerals in shales are at present poorly understood. Sorption measurements in combination scattering techniques could provide fundamental insight into the mechanisms governing CO2-clay interaction. Volumetric sorption techniques have assessed the sorption of supercritical CO2 onto coal (Gensterblum et al., 2010; Gensterblum et al., 2009), porous silica (Rother et al., 2012a) and clays as a means of exploring the potential of large-scale storage of anthropogenic CO2 in geological reservoirs (Busch et al., 2008). On different clay minerals and shales, positive values of excess sorption were measured at gas pressures up to 6 MPa, where the interfacial fluid is assumed to be denser than the bulk fluid. However, zero and negative values were obtained at higher densities, which suggests the adsorbed fluid becomes equal to and eventually less dense than the corresponding bulk fluid, or that the clay minerals expand on CO2 charging. Using a combination of neutron diffraction and excess sorption measurements, we recently deduced the interlayer density of scCO2 in Na-montmorillonite clay in its single-layer hydration state (Rother et al., 2012b), and confirmed its low density, as well as the expansion of the basal spacings. We performed neutron diffraction experiments at the FRMII diffractometer on smectite, kaolinite and illite samples. These confirmed that CO2 enters the interlayer spaces of monohydrated (D2O) smectites exchanged with Ca. The changes were proven to be fully reversible and mainly take place between 0 and 60 bar CO2. For a smectite exchanged with (CuTrien)2+ a decrease in intensity of the basal reflections with pressure was recorded, but no expansion of the basal spacing was observed. For kaolinite, similar changes in intensity upon CO2 addition were observed, but they correspond to a relative decrease of the intensity of the hk reflections. Measurements on illite yielded an unexpected increase in intensity of the basal reflections upon CO2 charging.

  7. Diagenesis and clay mineral formation at Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    Bridges, J. C.; Schwenzer, S. P.; Leveille, R.; Westall, F.; Wiens, R. C.; Mangold, N.; Bristow, T.; Edwards, P.; Berger, G.

    2015-01-01

    Mars Science Laboratory rover Curiosity found host rocks of basaltic composition and alteration assemblages containing clay minerals at Yellowknife Bay, Gale Crater. On the basis of the observed host rock and alteration minerals, we present results of equilibrium thermochemical modeling of the Sheepbed mudstones of Yellowknife Bay in order to constrain the formation conditions of its secondary mineral assemblage. Building on conclusions from sedimentary observations by the Mars Science Laboratory team, we assume diagenetic, in situ alteration. The modeling shows that the mineral assemblage formed by the reaction of a CO2-poor and oxidizing, dilute aqueous solution (Gale Portage Water) in an open system with the Fe-rich basaltic-composition sedimentary rocks at 10-50°C and water/rock ratio (mass of rock reacted with the starting fluid) of 100-1000, pH of ~7.5-12. Model alteration assemblages predominantly contain phyllosilicates (Fe-smectite, chlorite), the bulk composition of a mixture of which is close to that of saponite inferred from Chemistry and Mineralogy data and to that of saponite observed in the nakhlite Martian meteorites and terrestrial analogues. To match the observed clay mineral chemistry, inhomogeneous dissolution dominated by the amorphous phase and olivine is required. We therefore deduce a dissolving composition of approximately 70% amorphous material, with 20% olivine, and 10% whole rock component.

  8. Evidence for microbial liberation of structurally-coordinated iron in clay minerals as a nutrient source in the world ocean

    NASA Astrophysics Data System (ADS)

    Metcalfe, K. S.; Gaines, R. R.; Trang, J.; Scott, S.; Crane, E. J.; Lackey, J.; Prokopenko, M. G.; Berelson, W.

    2012-12-01

    Clay minerals are the most abundant materials found at the surface of earth and they are the primary constituents of marine sediments. Iron, a limiting nutrient in many marine settings, is a common constituent of clay minerals. Recent in vitro experimental evidence has shown that lab cultures of Fe-reducing bacteria are able to utilize structurally-bound Fe from the crystal lattice of nontronite, an uncommon and particularly Fe-rich (> 12 wt.%) smectitie. Reduction of structurally-coordinated Fe results in both the liberation of Fe(II) to solution, where it is available for other biotic processes, as well as the transformation of smectite to illite. However, it remains unclear: 1. whether Fe-reducers are able to access structurally coordinated Fe found at low wt.% in common clay minerals; and 2. if naturally occuring populations of Fe-reducers are able to reduce structurally coordinated Fe as are some lab strains. In order to address these questions, we conducted in vitro experiments using a suite of sixteen clay minerals with low (0.8 wt.%) to high (13.9 wt.%) Fe concentrations. Clays were treated with Na-dithionite solution to remove surface-bound Fe, isolating for study Fe sourced from within the clay crystal lattice. Experimental evidence clearly indicates that, under in vitro conditions, Fe(III) bound in common clay minerals is available for reduction by the lab strain Shewanella oneidensis MR-1 as well as by naturally-occuring consortia of Fe-reducers cultured from the San Pedro and Santa Monica Basins. Our findings suggest that common clay minerals may represent a large and previously unrecognized pool of bioavailable Fe in the world ocean that contributes significantly to biogeochemical cycling of Fe and C.

  9. Program and Abstracts for Clay Minerals Society 28th Annual Meeting

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This volume contains abstracts that were accepted for presentation at the annual meeting. Some of the main topics covered include: (1) fundamental properties of minerals and methods of mineral analysis; (2) surface chemistry; (3) extraterrestrial clay minerals; (4) geothermometers and geochronometers; (5) smectite, vermiculite, illite, and related reactions; (6) soils and clays in environmental research; (7) kaolinite, halloysite, iron oxides, and mineral transformations; and (8) clays in lakes, basins, and reservoirs.

  10. Bioreduction of Fe-bearing clay minerals and their reactivity toward pertechnetate (Tc-99)

    SciTech Connect

    Bishop, Michael E.; Dong, Hailiang; Kukkadapu, Ravi K.; Liu, Chongxuan; Edelmann, Richard E.

    2011-07-01

    99Technetium (99Tc) is a fission product of uranium-235 and plutonium-239 and poses a high environmental hazard due to its long half-life (t1/2 = 2.13 x 105 y), abundance in nuclear wastes, and environmental mobility under oxidizing conditions [i.e., Tc(VII)]. Under reducing conditions, Tc(VII) can be reduced to insoluble Tc(IV). Ferrous iron [Fe(II)], either in aqueous form or in mineral form, has been used to reduce Tc(VII) to Tc(IV). However, the reactivity of Fe(II) from clay minerals, other than nontronite, toward immobilization of Tc(VII) and its role in retention of reduced Tc(IV) have not been investigated. In this study the reactivity of a suite of clay minerals toward Tc(VII) reduction and immobilization was evaluated. The clay minerals chosen for this study included five members in the smectite-illite (S-I) series, (montmorillonite, nontronite, rectorite, mixed layered I-S, and illite), chlorite, and palygorskite. Fe-oxides were removed from these minerals with a modified dithionite-citrate-bicarbonate (DCB) procedure. The total Fe content of these clay minerals, after Fe-oxide removal, ranged from 0.7 to 30.4% by weight, and the Fe(III)/Fe(total) ratio ranged from 44.9 to 98.5%. X-ray diffraction (XRD) and Mössbauer spectroscopy results showed that after Fe oxide removal the clay minerals were free of Fe-oxides. Scanning electron microscopy (SEM) revealed that little dissolution occurred during the DCB treatment. Bioreduction experiments were performed in bicarbonate buffer (pH-7) with Fe(III) in the clay minerals as the sole electron acceptor, lactate as the sole electron donor, and Shewanella Putrifaciens CN32 cells as mediators. In select tubes, anthraquinone-2,6-disulfate (AQDS) was added as electron shuttle to facilitate electron transfer. The extent of Fe(III) bioreduction was the highest for chlorite (~43 wt%) and the lowest for palygorskite (~4.17 wt%). In the S-I series, NAu-2 was the most reducible (~31 %) and illite the least (~0.4 %). The extent and initial rate of bioreduction were positively correlated with the percent smectite in the S-I series (i.e., layer expandability). Fe(II) in the bioreduced clay minerals subsequently was used to reduce Tc(VII) to Tc(IV) in PIPES buffer. Similar to the trend of bioreduction, in the S-I series, reduced smectite showed the highest reactivity toward Tc(VII), and reduced illite exhibited the least. The initial rate of Tc(VII) reduction, after normalization to clay and Fe(II) concentrations, was positively correlated with the percent smectite in the S-I series. Fe(II) in chlorite and palygorskite was also reactive toward Tc(VII) reduction. These data demonstrate that crystal chemical parameters (layer expandability, Fe and Fe(II) contents, and surface area etc.) play important roles in controlling the extent and rate of bioreduction and the reactivity toward Tc(VII) reduction. Reduced Tc(IV) resides within clay mineral matrix, and this association could minimize any potential of reoxidation over long term.

  11. Neocrystallization, fabrics and age of clay minerals from an exposure of the Moab Fault, Utah

    E-print Network

    Neocrystallization, fabrics and age of clay minerals from an exposure of the Moab Fault, Utah John Pronounced changes in clay mineral assemblages are preserved along the Moab Fault (Utah). Gouge is enriched. These mineralogical changes indicate that clay gouge is formed not solely through mechanical incorporation

  12. Reduced adsorption of caesium on clay minerals caused by various humic substances

    E-print Network

    Paris-Sud XI, Université de

    Reduced adsorption of caesium on clay minerals caused by various humic substances C. Dumat, S!ect of the addition of various humic substances on the adsorption of caesium on two mineral clays has been studied and ionic strength. Only a small proportion of the humic substance was adsorbed on the clays ((10

  13. THE LINK BETWEEN CLAY MINERAL WEATHERING AND THE FORMATION OF NI SURFACE PRECIPITATES

    E-print Network

    Sparks, Donald L.

    THE LINK BETWEEN CLAY MINERAL WEATHERING AND THE FORMATION OF NI SURFACE PRECIPITATES Andreas C, Schlieren, Switzerland Spectroscopic and microscopic studies have shown that Ni and Co sorption by clay:1 or 2:1 phyllosilicates requires the release ofA1 and Si from clay minerals. Due to similar metal

  14. Distribution of Clay Minerals in Lower Cook Inlet and Kodiak Shelf Sediment, Alaska

    E-print Network

    Distribution of Clay Minerals in Lower Cook Inlet and Kodiak Shelf Sediment, Alaska James R. llein-five surface samples from lower Cook Inlet and forty-three from Kodiak shelf, Alaska, were analyzed for clay percentages of clay minerals. This is because modern ocean currents vigorously rework surficial sediment

  15. Clay mineral variations in Holocene terrestrial sediments from the Indus Basin Anwar Alizai a,

    E-print Network

    Clift, Peter

    Clay mineral variations in Holocene terrestrial sediments from the Indus Basin Anwar Alizai a 23 February 2012 Keywords: XRD Clay mineralogy Monsoon Himalaya Indus Delta Floodplain Fluvial processes Large rivers We employed X-ray diffraction methods to quantify clay mineral assemblages

  16. Sorption of organic matter on clay minerals in aquatic system and influence on sedimentary organic preservation.

    E-print Network

    Paris-Sud XI, Université de

    Sorption of organic matter on clay minerals in aquatic system and influence on sedimentary organic on clay surfaces in aquatic environment influence organic sedimentation fluxes. It is well known in sediments ([1]). Direct contacts between clay minerals and organic molecules allow creation of organo

  17. Clay mineral distribution in surface sediments of the South Atlantic: sources, transport, and relation to oceanography

    Microsoft Academic Search

    Rainer Petschick; Gerhard Kuhn; Franz Gingele

    1996-01-01

    Surface samples, mostly from abyssal sediments of the South Atlantic, from parts of the equatorial Atlantic, and of the Antarctic Ocean, were investigated for clay content and clay mineral composition. Maps of relative clay mineral content were compiled, which improve previous maps by showing more details, especially at high latitudes. Large-scale relations regarding the origin and transport paths of detrital

  18. Iron(III)-bearing clay minerals enhance bioreduction of nitrobenzene by Shewanella putrefaciens CN32.

    PubMed

    Luan, Fubo; Liu, Yan; Griffin, Aron M; Gorski, Christopher A; Burgos, William D

    2015-02-01

    Iron-bearing clay minerals are ubiquitous in the environment, and the clay-Fe(II)/Fe(III) redox couple plays important roles in abiotic reduction of several classes of environmental contaminants. We investigated the role of Fe-bearing clay minerals on the bioreduction of nitrobenzene. In experiments with Shewanella putrefaciens CN32 and excess electron donor, we found that the Fe-bearing clay minerals montmorillonite SWy-2 and nontronite NAu-2 enhanced nitrobenzene bioreduction. On short time scales (<50 h), nitrobenzene reduction was primarily biologically driven, but at later time points, nitrobenzene reduction by biologically formed structural Fe(II) in the clay minerals became increasingly important. We found that chemically reduced (dithionite) iron-bearing clay minerals reduced nitrobenzene more rapidly than biologically reduced iron-bearing clay minerals despite the minerals having similar structural Fe(II) concentrations. We also found that chemically reduced NAu-2 reduced nitrobenzene faster as compared to chemically reduced SWy-2. The different reactivity of SWy-2 versus NAu-2 toward nitrobenzene was caused by different forms of structural clay-Fe(II) in the clay minerals and different reduction potentials (Eh) of the clay minerals. Because most contaminated aquifers become reduced via biological activity, the reactivity of biogenic clay-Fe(II) toward reducible contaminants is particularly important. PMID:25565314

  19. Clay minerals in Quaternary marine sediments from the southern Svalbard continental slope: palaeoenvironmental significance

    NASA Astrophysics Data System (ADS)

    Giorgetti, G.; Lucchi, R.; Macri, P.; Sagnotti, L.; Melis, R.; Morigi, C.; Villa, G.; Colmenero-Hidalgo, E.; Sierro, F. J.; Barcena, M.; Villarejo, J.; Camerlenghi, A.; Rebesco, M.

    2012-12-01

    Sediment cores have been collected in glaciomarine sequences from the continental slope of the the Storfjorden and Kveithola troughs (south Svalbard), on the northwestern Barents sea continental margin. This sedimentary system was investigated during the SVAIS and EGLACOM cruises both conceived within the International Polar Year (IPY) in 2007-2009. The cores were digitally X-radiographed and scanned for physical properties with a multi-sensor core logger in order to define sediment facies. Detailed palaeostratigraphic investigations together with palaeomagnetic and rock magnetic analyses and AMS dating were used to constrain the age model and for high-resolution inter-core correlation. Sediment samples were analyzed for textural characteristics and clay mineral content in order to define sediment provenance and depositional mechanisms. The clay mineral assemblage is mainly composed by illite (>40%) with chlorite content ranging between 10-40%, kaolinite ranging between 10-30%, and smectite content always minor than 20%. The older sediments consist of a stiff glacigenic diamicton that deposited during last glacial maximum (LGM) and silty clay sediments interbedded with sandy layers deposited during the previous interglacial stage MIS3. The clay mineral assemblage of the glacigenic diamicton contains mainly illite with no traces of smectite. The post-LGM sediment sequence is characterized by an increasing kaolinite and smectite content. Holocene sediments of the mid-slope contain the highest smectite content. The sediments recovered from the Kveithola Trough are characterized by the highest kaolinite and lowest illite content. On average, sediments in cores from the northern Storfjorden slope show higher illite and lower chlorite and kaolinite contents than sediments in cores from the southern Storfjorden and Kveithola slopes. In the northwestern Barents Sea continental margin, illite and chlorite derive from the meta-sedimentary rocks of Spitsbergen, while kaolinite derives from Triassic mudstones and sandstones, abundant in the eastern islands, and from Quaternary sediments outcropping on the seafloor of the Barents Sea. None of the rocks outcropping in the Svalbard archipelago can yield smectite. Our interpretation is that smectite derives from the basaltic Greenland Faroe Ridge and Iceland being transported to the North by the West Spitsbergen Current (WSC). The clay mineral assemblage of the glacigenic diamicton derives from physically-weathered products originated by subglacial ablation of the rocks outcropping in Svalbard without any influence of the WSC transported sediments. During deglaciation and ice retreat, the strengthened North Atlantic water transported smectite from the South, enriching recent sediments in this clay mineral.

  20. Towards an understanding of the role of clay minerals in crude oil formation, migration and accumulation

    NASA Astrophysics Data System (ADS)

    Wu, Lin Mei; Zhou, Chun Hui; Keeling, John; Tong, Dong Shen; Yu, Wei Hua

    2012-12-01

    This article reviews progress in the understanding of the role of clay minerals in crude oil formation, migration and accumulation. Clay minerals are involved in the formation of kerogen, catalytic cracking of kerogen into petroleum hydrocarbon, the migration of crude oil, and the continued change to hydrocarbon composition in underground petroleum reservoirs. In kerogen formation, clay minerals act as catalysts and sorbents to immobilize organic matter through ligand exchange, hydrophobic interactions and cation bridges by the mechanisms of Maillard reactions, polyphenol theory, selective preservation and sorptive protection. Clay minerals also serve as catalysts in acid-catalyzed cracking of kerogen into petroleum hydrocarbon through Lewis and Brønsted acid sites on the clay surface. The amount and type of clay mineral affect the composition of the petroleum. Brønsted acidity of clay minerals is affected by the presence and state of interlayer water, and displacement of this water is a probable driver in crude oil migration from source rocks. During crude oil migration and accumulation in reservoirs, the composition of petroleum is continually modified by interaction with clay minerals. The clays continue to function as sorbents and catalysts even while they are being transformed by diagenetic processes. The detail of chemical interactions and reaction mechanisms between clay minerals and crude oil formation remains to be fully explained but promises to provide insights with broader application, including catalytic conversion of biomass as a source of sustainable energy into the future.

  1. Clays and Clay Minerals, Vol.45, No.5, 690-708, 1997. COMPARISON OF HEMATITE COAGULATION BY CHARGE

    E-print Network

    Chorover, Jon

    Clays and Clay Minerals, Vol.45, No.5, 690-708, 1997. COMPARISON OF HEMATITE COAGULATION BY CHARGE aggregates were examined by dynamic and static light scattering techniques. A large range in coagulation neutralization or counterion screening was 1.7 2 0.1. A reduction in the rate of coagulation in KC1 for [KC1

  2. Influence of clay minerals on the hydrolysis of carbamate pesticides.

    PubMed

    Wei, J; Furrer, G; Kaufmann, S; Schulin, R

    2001-06-01

    Using batch experiments, we investigated the influence of clay minerals (montmorillonite, beidellite, illite, and vermiculite) on the hydrolysis of five carbamate pesticides: carbosulfan, carbofuran, aldicarb, pirimicarb, and chlorpropham. Compared to the other minerals, montmorillonite had the strongest influence on the hydrolysis of these carbamates. Montmorillonite enhanced the hydrolysis of carbosulfan and aldicarb. In contrast, the hydrolysis of chlorpropham was inhibited by montmorillonite, probably because of its strong adsorption on montmorillonite. The hydrolysis of pirimicarb was not affected by montmorillonite. The presence of organic substances, phosphate, and fluoride in suspensions decreased the catalytic activity of montmorillonite. Surface acidity of montmorillonite and/or formation of surface chelates are probably the key factors of surface catalysis in the case of the hydrolysis of carbosulfan. PMID:11414023

  3. Surficial clay mineral distribution on the southwestern continental margin of India: evidence of input from the Bay of Bengal

    NASA Astrophysics Data System (ADS)

    Chauhan, Onkar S.; Gujar, A. R.

    1996-03-01

    Analyses of spatial distribution of clay minerals, sediment texture, and > 63 ?m fractions of the grab samples from the S W continental margin of India exhibit: (i) higher contents of illite and chlorite on the lower slope and (ii) a well-defined no-clay zone on the entire shelf. Kaolinite and smectite are also present in significant quantities on the slope with traces of gibbsite and palygorskite in some samples. The high contents of illite and chlorite (clay minerals which are not abundant in the soils and estuarine sediments of this region) in the southern region of the study area are evidence for sediment contribution from the Bay of Bengal waters (BBW), which enter this region after the SW monsoon. Distribution trends of kaolinite, smectite, gibbsite, and laterite granules on the slope are suggestive of contribution from chemically weathered soils of Peninsular India.

  4. Kinetic Study of Denatonium Sorption to Smectite Clay Minerals.

    PubMed

    Crosson, Garry S; Sandmann, Emily

    2013-06-01

    The denatonium cation, as a benzoate salt, is the most bitter cation known to modern society and is frequently added to consumer products to reduce accidental and intentional consumption by humans and animals. Denatonium can enter the environment by accidental discharges, potentially rendering water supplies undrinkable. Interactions of denatonium with soil components (i.e., smectite minerals) ultimately control the environmental fate of denatonium, but the current literature is devoid of studies that evaluate denatonium sorption to smectite minerals. This study investigated the mechanism and kinetics of denatonium sorption to smectite clay minerals as a function of smectite type, temperature, pH and ionic strength. Uptake by synthetic mica montmorillonite (Syn-1), Wyoming montmorillonite (SWy-2), and Texas montmorillonite (STx-1b) at 305K was rapid, with equilibrium being reached within 2?min for all clays. Complete removal of denatonium was observed for STx-1b at pH 6.9, while partial removal was observed for Syn-1 and SWy-2. Kinetic behavior of SWy-2 and Syn-1 is consistent with a pseudo-second-order model at 305K. An activation energy of +25.9 kJ/mol was obtained for sorption to Syn-1 and was independent of temperature between 286K and 338K. Activation-free energy (?G*), activation enthalpy (?H*), and activation entropy (?S*) for Syn-1 were found to be +62.91 kJ/mol, +23.36 kJ/mol, and -0.130 kJ/(K·mol), respectively. Sorption capacities at pH 3.6, 6.9, and 8.2 were constant at 1.3×10(-2) g denatonium/g clay; however, the kinetic rate constant increased by 56%, going from acidic to basic solution conditions. Distribution coefficients were negatively correlated with ionic strength, suggesting cation exchange. Collectively, results suggested that smectite minerals can serve as efficient sinks for denatonium cations. This is much-needed information for agencies developing regulations regarding denatonium usage and for water treatment professionals who may ultimately have to treat denatonium-impacted water supplies. PMID:23781128

  5. Kinetic Study of Denatonium Sorption to Smectite Clay Minerals

    PubMed Central

    Crosson, Garry S.; Sandmann, Emily

    2013-01-01

    Abstract The denatonium cation, as a benzoate salt, is the most bitter cation known to modern society and is frequently added to consumer products to reduce accidental and intentional consumption by humans and animals. Denatonium can enter the environment by accidental discharges, potentially rendering water supplies undrinkable. Interactions of denatonium with soil components (i.e., smectite minerals) ultimately control the environmental fate of denatonium, but the current literature is devoid of studies that evaluate denatonium sorption to smectite minerals. This study investigated the mechanism and kinetics of denatonium sorption to smectite clay minerals as a function of smectite type, temperature, pH and ionic strength. Uptake by synthetic mica montmorillonite (Syn-1), Wyoming montmorillonite (SWy-2), and Texas montmorillonite (STx-1b) at 305K was rapid, with equilibrium being reached within 2?min for all clays. Complete removal of denatonium was observed for STx-1b at pH 6.9, while partial removal was observed for Syn-1 and SWy-2. Kinetic behavior of SWy-2 and Syn-1 is consistent with a pseudo–second-order model at 305K. An activation energy of +25.9 kJ/mol was obtained for sorption to Syn-1 and was independent of temperature between 286K and 338K. Activation-free energy (?G*), activation enthalpy (?H*), and activation entropy (?S*) for Syn-1 were found to be +62.91 kJ/mol, +23.36 kJ/mol, and ?0.130 kJ/(K·mol), respectively. Sorption capacities at pH 3.6, 6.9, and 8.2 were constant at 1.3×10?2 g denatonium/g clay; however, the kinetic rate constant increased by 56%, going from acidic to basic solution conditions. Distribution coefficients were negatively correlated with ionic strength, suggesting cation exchange. Collectively, results suggested that smectite minerals can serve as efficient sinks for denatonium cations. This is much-needed information for agencies developing regulations regarding denatonium usage and for water treatment professionals who may ultimately have to treat denatonium-impacted water supplies. PMID:23781128

  6. TOXICOLOGICAL EVALUATION AND METAL BIOAVAILABILITY IN PREGNANT RATS FOLLOWING EXPOSURE TO CLAY MINERALS IN THE DIET

    Microsoft Academic Search

    Melinda C. Wiles; Henry J. Huebner; Evans Afriyie-Gyawu; Robert J. Taylor; Gerald R. Bratton; Timothy D. Phillips

    2004-01-01

    Silicate clays are frequently added to animal feeds to bind and reduce the bioavailability of mycotoxins in the gastrointestinal tract. However, the bioavailability of trace metals in these clay feed additives has not been thoroughly investigated. Clays that act nonselectively may interact with nutrients, minerals, and other feedborne chemicals to pose significant hidden risks. In this study, a calcium montmorillonite

  7. Effects of clay mineral turbidity on dissolved organic carbon and bacterial production

    Microsoft Academic Search

    Todd Tietjen; Anssi V. Vähätalo; Robert G. Wetzel

    2005-01-01

    Effects of inorganic turbidity from clay minerals on allochthonous dissolved organic matter (DOM), its consumption by bacteria and photodegradation by solar radiation were investigated. In controlled experiments of adsorption of DOM of six specific leaf leachates onto montmorillonite, kaolinite, and clay extracted from drainage basin soil, up to 31 mg C of leaf leachate was adsorbed g clay ?1. A suspension

  8. ORIGINAL PAPER On the origin of mixed-layered clay minerals from the

    E-print Network

    ORIGINAL PAPER On the origin of mixed-layered clay minerals from the San Andreas Fault at 2.5­3 km. The characteristics of authigenic illite­smectite (I­S) and chlorite­smectite (C­S) mixed- layer mineral clays of the dominant authigenic clay species across the San Andreas Fault zone (sampled at 3,066 and 3,436 m measured

  9. Review of XRD-based quantitative analyses of clay minerals in soils: the suitability of mineral intensity factors

    Microsoft Academic Search

    Maren Kahle; Markus Kleber; Reinhold Jahn

    2002-01-01

    The determination of the types and relative amounts of the minerals present in soil forms an essential component of most soil characterization efforts. This paper reviews protocols for XRD-based quantitative clay mineral analysis in soils, with emphasis on methods using mineral intensity factors in combination with the so-called 100% approach. We summarize methodological differences and characteristic features and give information

  10. Cation exchange dynamics confined in a synthetic clay mineral

    NASA Astrophysics Data System (ADS)

    Grassi, G.; Michels, L.; Rozynek, Z.; Altoé, M. A. S.; dos Santos, E. C.; da Fonseca, C. L. S.; Droppa, R.; Gholamipour-Shirazi, A.; Fossum, J. O.; da Silva, G. J.

    2014-09-01

    In this work we report X-Ray Diffraction (XRD) and Energy Dispersive X-Ray Spectroscopy (EDS) measurements to investigate the confined cation exchange process in saline aqueous suspensions of a synthetic clay mineral from Lithium-Fluorohectorite to Nickel-Fluorohectorite, as well as the reverse process from Nickel-Fluorohectorite to Lithium-Fluorohectorite and also from Lithium-Fluorohectorite to Sodium-Fluorohectorite. The dynamics of these cation exchanges was followed and it was observed that these processes can be faster than 1 minute. The results are compared to the observations on samples prepared by cation exchange procedures for which the exchange process was performed on the time-scale of months.

  11. Role of clay minerals on the carbonate chemistry in a marine clay formation Lerouge C., Grangeon S., Mazurek M., Wille G.

    E-print Network

    Boyer, Edmond

    Role of clay minerals on the carbonate chemistry in a marine clay formation Lerouge C., Grangeon S., Mazurek M., Wille G. Samples from different levels of the Opalinus clay formation at Benken were studied. At the scale of the formation, the trace element content in calcite is anticorrelated with clay content

  12. Analyses of Adsorption Kinetics Using a Stirred-Flow Chamber: II. Potassium-Calcium Exchange on Clay Minerals

    E-print Network

    Sparks, Donald L.

    on Clay Minerals Matthew J. Eick,* Asher Bar-Tal, Donald L. Sparks, and Sala Feigenbaum ABSTRACT Potassium in soils dominated by vermiculitic and micaceous clay minerals. "DOTASSIUM is AN ESSENTIAL ELEMENT and comparing different ki- netic methods have not been solved. Kinetics of K adsorption on clay minerals have

  13. INFLUENCE OF MECHANICAL COMPACTION AND CLAY MINERAL DIAGENESIS ON THE MICROFABRIC AND PORE-SCALE PROPERTIES OF DEEP-WATER

    E-print Network

    INFLUENCE OF MECHANICAL COMPACTION AND CLAY MINERAL DIAGENESIS ON THE MICROFABRIC AND POREÐWe report on how the effects of mechanical compaction and clay mineral diagenesis have affected comprising a mixture of lath-shaped clay minerals and more equidimensional grains such as quartz and feldspar

  14. MAX--An Interactive Computer Program for Teaching Identification of Clay Minerals by X-ray Diffraction.

    ERIC Educational Resources Information Center

    Kohut, Connie K.; And Others

    1993-01-01

    Discusses MAX, an interactive computer program for teaching identification of clay minerals based on standard x-ray diffraction characteristics. The program provides tutorial-type exercises for identification of 16 clay standards, self-evaluation exercises, diffractograms of 28 soil clay minerals, and identification of nonclay minerals. (MDH)

  15. Formation of replicating saponite from a gel in the presence of oxalate: implications for the formation of clay minerals in carbonaceous chondrites and the origin of life.

    PubMed

    Schumann, Dirk; Hartman, Hyman; Eberl, Dennis D; Sears, S Kelly; Hesse, Reinhard; Vali, Hojatollah

    2012-06-01

    The potential role of clay minerals in the abiotic origin of life has been the subject of ongoing debate for the past several decades. At issue are the clay minerals found in a class of meteorites known as carbonaceous chondrites. These clay minerals are the product of aqueous alteration of anhydrous mineral phases, such as olivine and orthopyroxene, that are often present in the chondrules. Moreover, there is a strong correlation in the occurrence of clay minerals and the presence of polar organic molecules. It has been shown in laboratory experiments at low temperature and ambient pressure that polar organic molecules, such as the oxalate found in meteorites, can catalyze the crystallization of clay minerals. In this study, we show that oxalate is a robust catalyst in the crystallization of saponite, an Al- and Mg-rich, trioctahedral 2:1 layer silicate, from a silicate gel at 60°C and ambient pressure. High-resolution transmission electron microscopy analysis of the saponite treated with octadecylammonium (n(C)=18) cations revealed the presence of 2:1 layer structures that have variable interlayer charge. The crystallization of these differently charged 2:1 layer silicates most likely occurred independently. The fact that 2:1 layer silicates with variable charge formed in the same gel has implications for our understanding of the origin of life, as these 2:1 clay minerals most likely replicate by a mechanism of template-catalyzed polymerization and transmit the charge distribution from layer to layer. If polar organic molecules like oxalate can catalyze the formation of clay-mineral crystals, which in turn promote clay microenvironments and provide abundant adsorption sites for other organic molecules present in solution, the interaction among these adsorbed molecules could lead to the polymerization of more complex organic molecules like RNA from nucleotides on early Earth. PMID:22794298

  16. Clay Minerals in Mawrth Vallis Region of Mars

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This map showing the location of some clay minerals in of a portion of the Mawrth Vallis region of Mars covers an area about 10 kilometers (6.2 mile) wide. The map is draped over a topographical model that exaggerates the vertical dimension tenfold.

    The mineral mapping information comes from an image taken on Sept. 21, 2007, by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Iron-magnesium phyllosilicate is shown in red. Aluminum phyllosyllicate is shown in blue. Hydrated silica and a ferrous iron phase are shown in yellow/green.

    The topographical information comes from the Mars Orbiter Laser Altimeter instrument on NASA's Mars Global Surveyor orbiter.

    Mawrth Vallis is an outflow channel centered near 24.7 degrees north latitude, 339.5 degrees east longitude, in northern highlands of Mars.

    CRISM is one of six science instruments on the Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, Laurel, Md., the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the orbiter.

  17. Sm-Nd dating of Fig Tree clay minerals of the Barberton greenstone belt, South Africa

    NASA Technical Reports Server (NTRS)

    Toulkeridis, T.; Goldstein, S. L.; Clauer, N.; Kroner, A.; Lowe, D. R.

    1994-01-01

    Sm-Nd isotopic data from carbonate-derived clay minerals of the 3.22-3.25 Ga Fig Tree Group, Barberton greenstone belt, South Africa, form a linear array corresponding to an age of 3102 +/- 64 Ma, making these minerals the oldest dated clays on Earth. The obtained age is 120-160 m.y. younger than the depositional age determined by zircon geochronology. Nd model ages for the clays range from approximately 3.39 to 3.44 Ga and almost cover the age variation of the Barberton greenstone belt rocks, consistent with independent evidence that the clay minerals are derived from material of the belt. The combined isotopic and mineralogical data provide evidence for a cryptic thermal overprint in the sediments of the belt. However, the highest temperature reached by the samples since the time of clay-mineral formation was <300 degrees C, lower than virtually any known early Archean supracrustal sequence.

  18. Geochemical Consequences of Widespread Clay Mineral Formation in Mars' Ancient Crust

    NASA Astrophysics Data System (ADS)

    Ehlmann, Bethany L.; Berger, Gilles; Mangold, Nicolas; Michalski, Joseph R.; Catling, David C.; Ruff, Steven W.; Chassefière, Eric; Niles, Paul B.; Chevrier, Vincent; Poulet, Francois

    2013-01-01

    Clays form on Earth by near-surface weathering, precipitation in water bodies within basins, hydrothermal alteration (volcanic- or impact-induced), diagenesis, metamorphism, and magmatic precipitation. Diverse clay minerals have been detected from orbital investigation of terrains on Mars and are globally distributed, indicating geographically widespread aqueous alteration. Clay assemblages within deep stratigraphic units in the Martian crust include Fe/Mg smectites, chlorites and higher temperature hydrated silicates. Sedimentary clay mineral assemblages include Fe/Mg smectites, kaolinite, and sulfate, carbonate, and chloride salts. Stratigraphic sequences with multiple clay-bearing units have an upper unit with Al-clays and a lower unit with Fe/Mg-clays. The typical restriction of clay minerals to the oldest, Noachian terrains indicates a distinctive set of processes involving water-rock interaction that was prevalent early in Mars history and may have profoundly influenced the evolution of Martian geochemical systems. Current analyses of orbital data have led to the proposition of multiple clay-formation mechanisms, varying in space and time in their relative importance. These include near-surface weathering, formation in ice-dominated near-surface groundwaters, and formation by subsurface hydrothermal fluids. Near-surface, open system formation of clays would lead to fractionation of Mars' crustal reservoir into an altered crustal reservoir and a sedimentary reservoir, potentially involving changes in the composition of Mars' atmosphere. In contrast, formation of clays in the subsurface by either aqueous alteration or magmatic cooling would result in comparatively little geochemical fractionation or interaction of Mars' atmospheric, crustal, and magmatic reservoirs, with the exception of long-term sequestration of water. Formation of clays within ice would have geochemical consequences intermediate between these endmembers. We outline the future analyses of orbital data, in situ measurements acquired within clay-bearing terrains, and analyses of Mars samples that are needed to more fully elucidate the mechanisms of martian clay formation and to determine the consequences for the geochemical evolution of the planet.

  19. First-principles study of illite-smectite and implications for clay mineral systems

    Microsoft Academic Search

    Lars Stixrude; Donald R. Peacor

    2002-01-01

    Illite-smectite interstratified clay minerals are ubiquitous in sedimentary basins and they have been linked to the maturation, migration and trapping of hydrocarbons, rock cementation, evolution of porewater chemistry during diagenesis and the development of pore pressure. But, despite the importance of these clays, their structures are controversial. Two competing models exist, each with profoundly different consequences for the understanding of

  20. Use of clay minerals in reconstructing geological processes: recent advances and some perspectives

    Microsoft Academic Search

    J. Srodon

    1999-01-01

    This article reviews that clay literature from the last ten years, which is devoted to the applications of clay minerals in the interpretation of geological processes in sedimentary basins. The results, selected by the author as being of particular interest, are presented, arranged according to the successive phases of the rock cycle. The research field defined in the title has

  1. Dynamic role of “illite-like” clay minerals in temperate soils: facts and hypotheses

    Microsoft Academic Search

    P. Barré; B. Velde; L. Abbadie

    2007-01-01

    Analysis of new data and reinterpretation of published information for clay minerals found in temperate climate soil profiles\\u000a indicates that there is often a gradient of “illite-like” clay minerals with depth. We used the term “illite-like” because\\u000a these observations are based on X-Ray Diffractogram patterns and not on layer charge measurements which allow to define properly\\u000a illite. It appears that

  2. Application of the Modified Methylene Blue Test to Detect Clay Minerals in Coarse Aggregate Fines

    E-print Network

    Pitre, Brandon

    2012-12-04

    ................................................................................................................. 89 vii LIST OF FIGURES Page Figure 2.1. Synthesis pattern for the clay minerals. (from Mitchell and Soga 2005)......... 9 Figure 3.1. Dry sample of aggregate fines... by the following: small particle size, a net negative charge, some degree of plasticity when mixed with water, and high weathering resistance. Clay minerals are primarily hydrous aluminum silicates (Mitchell and Soga 2005). The crystalline 7 structure...

  3. Clay minerals of recent marine sediments to the west of the Mississippi Delta 

    E-print Network

    McAllister, Raymond Francis

    1958-01-01

    CLAY MINERALS OF RECENT MARINE SEDIMENTS 10 THE WEST OP THE MISSISSIPPI DKLTA A Dissertation By RAYMOND ERANCIS McALLI9TER> Jr. Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment... of the requirements for the degree of DOCTOR OF PHILOSOPHY IN OCEANOGRAPHY May* 1958 Major Subject: Geological Oceanography CLAY MINERALS OF RECENT MARINE SEDIMENTS TO THE WEST OF THE MISSISSIPPI DELTA A Dissertation RAYMOND FRANCIS McALLISTER, Jr. Approved...

  4. A Study of the Adsorption of Ni(II) and Cu(II) by Clay Minerals

    Microsoft Academic Search

    M. H. Koppelman; J. G. DILLARD

    1977-01-01

    The adsorption of Ni(II) and Cu(II) on to the clay minerMs kaolinite, chlorite, and illite has been investigated. The quantity of Ni(II) at pH 6 and Cu(II) at pH 5 adsorbed has been found to vary in the manner chlorite > illite > kaolinite. Examination of the mode of bonding of the metal ions to the clay minerals using X-ray

  5. CLAY MINERALOGY ALONG THE LATERITE PROFILE IN HUBEI, SOUTH CHINA: MINERAL EVOLUTION AND EVIDENCE FOR EOLIAN ORIGIN

    E-print Network

    Li, Zhaohui

    CLAY MINERALOGY ALONG THE LATERITE PROFILE IN HUBEI, SOUTH CHINA: MINERAL EVOLUTION AND EVIDENCE in more detail the associated mineralogical evolution, i.e. clay mineral composition, structural characteristics of clays in various beds with different degrees of weathering along the laterite profile

  6. The possible role of nannobacteria (dwarf bacteria) in clay-mineral diagenesis and the importance of careful sample preparation in high-magnification SEM study

    SciTech Connect

    Folk, R.L.; Lynch, F.L. [Univ. of Texas, Austin, TX (United States)

    1997-05-01

    Bacterial textures are present on clay minerals in Oligocene Frio Formation sandstones from the subsurface of the Corpus Christi area, Texas. In shallower samples, beads 0.05--0.1 {micro}m in diameter rim the clay flakes; at greater depth these beads become more abundant and eventually are perched on the ends of clay filaments of the same diameter. The authors believe that the beads are nannobacteria (dwarf forms) that have precipitated or transformed the clay minerals during burial of the sediments. Rosettes of chlorite also contain, after HCl etching, rows of 0.1 {micro}m bodies. In contrast, kaolinite shows no evidence of bacterial precipitation. The authors review other examples of bacterially precipitated clay minerals. A danger present in interpretation of earlier work (and much work of others) is the development of nannobacteria-looking artifacts caused by gold coating times in excess of one minute; the authors strongly recommend a 30-second coating time. Bacterial growth of clay minerals may be a very important process both in the surface and subsurface.

  7. Evaluation of the medicinal use of clay minerals as antibacterial agents.

    PubMed

    Williams, Lynda B; Haydel, Shelley E

    2010-07-01

    Natural clays have been used to heal skin infections since the earliest recorded history. Recently our attention was drawn to a clinical use of French green clay (rich in Fe-smectite) for healing Buruli ulcer, a necrotizing fasciitis ('flesh-eating' infection) caused by Mycobacterium ulcerans. These clays and others like them are interesting as they may reveal an antibacterial mechanism that could provide an inexpensive treatment for this and other skin infections, especially in global areas with limited hospitals and medical resources.Microbiological testing of two French green clays, and other clays used traditionally for healing, identified three samples that were effective at killing a broad-spectrum of human pathogens. A clear distinction must be made between 'healing clays' and those we have identified as antibacterial clays. The highly adsorptive properties of many clays may contribute to healing a variety of ailments, although they are not antibacterial. The antibacterial process displayed by the three identified clays is unknown. Therefore, we have investigated the mineralogical and chemical compositions of the antibacterial clays for comparison with non-antibacterial clays in an attempt to elucidate differences that may lead to identification of the antibacterial mechanism(s).The two French green clays used to treat Buruli ulcer, while similar in mineralogy, crystal size, and major element chemistry, have opposite effects on the bacterial populations tested. One clay deposit promoted bacterial growth whereas another killed the bacteria. The reasons for the difference in antibacterial properties thus far show that the bactericidal mechanism is not physical (e.g., an attraction between clay and bacteria), but by a chemical transfer or reaction. The chemical variables are still under investigation.Cation exchange experiments showed that the antibacterial component of the clay can be removed, implicating exchangeable cations in the antibacterial process. Furthermore, aqueous leachates of the antibacterial clays effectively kill the bacteria. Progressively heating the clay leads first to dehydration (200 degrees C), then dehydroxylation (550 degrees C or more), and finally to destruction of the clay mineral structure by (~900 degrees C). By identifying the elements lost after each heating step, and testing the bactericidal effect of the heated product, we eliminated many toxins from consideration (e.g., microbes, organic compounds, volatile elements) and identified several redox-sensitive refractory metals that are common among antibacterial clays. We conclude that the pH and oxidation state buffered by the clay mineral surfaces is key to controlling the solution chemistry and redox related reactions occurring at the bacterial cell wall. PMID:20640226

  8. Enhanced cellular preservation by clay minerals in 1 billion-year-old lakes

    NASA Astrophysics Data System (ADS)

    Wacey, David; Saunders, Martin; Roberts, Malcolm; Menon, Sarath; Green, Leonard; Kong, Charlie; Culwick, Timothy; Strother, Paul; Brasier, Martin D.

    2014-07-01

    Organic-walled microfossils provide the best insights into the composition and evolution of the biosphere through the first 80 percent of Earth history. The mechanism of microfossil preservation affects the quality of biological information retained and informs understanding of early Earth palaeo-environments. We here show that 1 billion-year-old microfossils from the non-marine Torridon Group are remarkably preserved by a combination of clay minerals and phosphate, with clay minerals providing the highest fidelity of preservation. Fe-rich clay mostly occurs in narrow zones in contact with cellular material and is interpreted as an early microbially-mediated phase enclosing and replacing the most labile biological material. K-rich clay occurs within and exterior to cell envelopes, forming where the supply of Fe had been exhausted. Clay minerals inter-finger with calcium phosphate that co-precipitated with the clays in the sub-oxic zone of the lake sediments. This type of preservation was favoured in sulfate-poor environments where Fe-silicate precipitation could outcompete Fe-sulfide formation. This work shows that clay minerals can provide an exceptionally high fidelity of microfossil preservation and extends the known geological range of this fossilization style by almost 500 Ma. It also suggests that the best-preserved microfossils of this time may be found in low-sulfate environments.

  9. Enhanced cellular preservation by clay minerals in 1 billion-year-old lakes.

    PubMed

    Wacey, David; Saunders, Martin; Roberts, Malcolm; Menon, Sarath; Green, Leonard; Kong, Charlie; Culwick, Timothy; Strother, Paul; Brasier, Martin D

    2014-01-01

    Organic-walled microfossils provide the best insights into the composition and evolution of the biosphere through the first 80 percent of Earth history. The mechanism of microfossil preservation affects the quality of biological information retained and informs understanding of early Earth palaeo-environments. We here show that 1 billion-year-old microfossils from the non-marine Torridon Group are remarkably preserved by a combination of clay minerals and phosphate, with clay minerals providing the highest fidelity of preservation. Fe-rich clay mostly occurs in narrow zones in contact with cellular material and is interpreted as an early microbially-mediated phase enclosing and replacing the most labile biological material. K-rich clay occurs within and exterior to cell envelopes, forming where the supply of Fe had been exhausted. Clay minerals inter-finger with calcium phosphate that co-precipitated with the clays in the sub-oxic zone of the lake sediments. This type of preservation was favoured in sulfate-poor environments where Fe-silicate precipitation could outcompete Fe-sulfide formation. This work shows that clay minerals can provide an exceptionally high fidelity of microfossil preservation and extends the known geological range of this fossilization style by almost 500?Ma. It also suggests that the best-preserved microfossils of this time may be found in low-sulfate environments. PMID:25068404

  10. Elemental Abundance Distributions in Basalt Clays and Meteorites: Is It a Biosignature?

    NASA Technical Reports Server (NTRS)

    Fisk, M. R.; Storrie-Lombardi, M. C.; Joseph, J.

    2005-01-01

    Volcanic glass altered by microorganisms exhibits distinctive textures differing significantly from abiotic alteration [1-4]. We have previously presented morphological evidence of bioweathering in sub-oceanic basalt glass [5] and olivine [6], and noted similar alterations in Nakhla [7]. We have also introduced an autonomous Bayesian probabilistic classification methodology to identify biotic and abiotic alteration in sub-oceanic basalts using elemental abundance data [8]. We now present data from multiple sub-oceanic sites addressing the more general question of utilizing elemental abundance distribution in clays as a valid biosignature for the exploration of putative clay alteration products in meteorites.

  11. Clay Minerals as Solid Acids and Their Catalytic Properties.

    ERIC Educational Resources Information Center

    Helsen, J.

    1982-01-01

    Discusses catalytic properties of clays, attributed to acidity of the clay surface. The formation of carbonium ions on montmorillonite is used as a demonstration of the presence of surface acidity, the enhanced dissociation of water molecules when polarized by cations, and the way the surface can interact with organic substances. (Author/JN)

  12. Effect of cyclodextrins on surface and pore properties of soil clay minerals.

    PubMed

    Jozefaciuk, G; Muranyi, A; Fenyvesi, E

    2001-12-15

    Although cyclodextrins are increasingly used in soil decontamination, little is known about their effects on soil physicochemical properties. In this work, the surface and pore properties of randomly methylated beta-cyclodextrin (RAMEB) and three typical clay minerals were characterized, and the effects of RAMEB concentrations on clay minerals were studied using water vapor adsorption-desorption and mercury intrusion porosimetry techniques. As compared to clay minerals, for pure RAMEB very large surface area and volume of nanometer-size pores (micropores) were determined. Energy of interaction with water vapor, volume of micrometer-size pores (mesopores), and fractal dimensions in both pore size ranges of RAMEB were lower than those of the minerals. When increasing amounts of RAMEB were added to the minerals, the surface area and micropore volume decreased and adsorption energy increased. The volume of mesopores decreased after RAMEB treatments for bentonite and kaolin and increased for illite. As deduced from the fractal dimensions increase, the pore structure of the minerals became more complex with RAMEB addition. The observed changes were in general contrary to these expected when RAMEB and minerals coexist as separate, nonreactive phases and suggested strong interaction of RAMEB with clay minerals. PMID:11775177

  13. Effect of pH on adsorption of arsenic and selenium from landfill leachate by clay minerals

    Microsoft Academic Search

    R. R. Frost; R. A. Griffin

    1977-01-01

    Adsorption of As(V), As(III), and Se(IV) anions from municipal landfill leachate solutions by the clay minerals kaolinite and montmorillonite is strongly dependent upon solution pH. The HâAsOâ⁻ and HSeOâ⁻ ions are the apparent primary As(V) and Se(IV) species being adsorbed by the clay minerals. Activation of the anion adsorption sites on the clay minerals by H\\/sup +\\/ ions is important

  14. Structure of a seafloor hydrothermal system in volcanic sediment: distribution of hydrothermal clay minerals, at the Iheya North Knoll, Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Miyoshi, Y.; Ishibashi, J.; Faure, K.; Uehara, S.

    2012-12-01

    Detailed investigation of clay minerals in hydrothermal fields provides fundamental information for understanding the physical and geochemical conditions within a hydrothermal system. Moreover, stable isotope geochemistry of clay minerals provides constraints on formation temperature. We investigated the distribution of clay minerals by XRD and TEM-EDS in a seafloor hydrothermal field at Iheya North Knoll in the Okinawa Trough, using cored sediment obtained from the Integrated Ocean Drilling Program (IODP) Expedition 331. The chemical composition and isotope values of the representative clay minerals were analyzed to obtain information on the hydrothermal system beneath the seafloor. Vertically, two different clay mineral facies are present. The boundary between the facies was identified at 6 mbsf (meters below the seafloor) at Site C0013 (100 m east of hydrothermal mound) and at 23 mbsf at Site C0014 (450 m east of the mound). In the lower facies (6 - 28 mbsf and 45 mbsf at Site C0013, 23 - 114 mbsf at Site C0014), Mg-chlorite and/or Mg-chlorite-smectite mixed layer minerals are dominant. They are associated with sericite in deeper parts (45 mbsf at Site C0013 and 38 - 114 mbsf at Site C0014). The ?18O values of the clays range from +1.5 to +4.7 ‰ (VSMOW) and the formation temperatures of the Mg-chlorite are estimated to be 230 - 300 °C, assuming a value from 0 to +1.5 ‰ for ?18Owater. The original sediment in the Iheya North Knoll is considered to have been volcanic of felsic chemical composition, so alteration to Mg-rich chlorite would require supply of substantial amount of Mg. Abundant formation of Mg-chlorite is attributed to mixing of hydrothermal fluid and seawater. In the upper facies at both sites, Al-rich clay minerals (kaolinite and montmorillonite) dominate. The ?18O values of clays range between +9.6 and +13.3 ‰ and formation temperatures are estimated to range between 120 - 160 °C. As kaolinite formation is favorable under acidic conditions, the kaolinite may be related to the vapor phase component enriched in CO2 and H2S, which would be generated by boiling of the hydrothermal fluid below the seafloor. In summary, occurrence of different facies of hydrothermal clay minerals reflects substantial variation in both temperature and chemical conditions between the upper and lower sediment layer. This difference may be related to discrete fluid flow within these sediment layers.

  15. Clay Mineral Surface Control of Organic Enrichment in Ancient Black Shales

    NASA Astrophysics Data System (ADS)

    Kennedy, M. J.; Mayer, L. M.; Arkadiusz, D.; Bristow, T. F.

    2006-12-01

    Previous work has shown a strong positive correlation between mineral surface area and adsorption of organic carbon in modern marine sediments. Our studies of black shales of varying thermal maturity and stages of diagenesis show a strong positive correlation between mineral surface area and total organic carbon in representative black shale deposits. This relation suggests that adsorption of dissolved carbon compounds or other mechanisms of preservation by clay mineral surfaces played a fundamental role in the burial and preservation of organic carbon. Additionally we have focused on the interlayer space of 2:1 smectitic clays. Our results imply that both polar and non-polar organic compounds are capable of gaining entry to the interlayer sites of smectite clay minerals and are confirmed by the disrupted X-ray diffraction pattern of the basal cleavage of artificial and natural samples of organic-rich smectitc samples. The MSA-TOC (mineral surface area) association implies organic carbon sequestration in an important class of black shales and petroleum source rocks may be more closely related to patterns of continental weathering and secular clay mineral trends than to the traditional models that consider only ocean water chemistry or marine productivity.

  16. Antarctic subtropical humid episode at the Paleocene-Eocene boundary: Clay-mineral evidence

    Microsoft Academic Search

    Christian Robert; James P. Kennett

    1994-01-01

    Clay-mineral assemblages from East Antarctica have been analyzed at high stratigraphic resolution (20 to 1 ka) throughout the interval from 55.6 to 55.0 Ma, which includes the terminal Paleocene isotopic excursion in Ocean Drilling Program Site 690B on Maud Rise (lat 65°S) in the Weddell Sea region. Changes in the clay associations reflect a major increase in chemical weathering caused

  17. Improved dewatering behavior of clay minerals dispersions via interfacial chemistry and particle interactions optimization

    Microsoft Academic Search

    Angus McFarlane; Kristen Bremmell; Jonas Addai-Mensah

    2006-01-01

    Orthokinetic flocculation of clay dispersions at pH 7.5 and 22?°C has been investigated to determine the influence of interfacial chemistry and shear on dewatering and particle interactions behavior. Modification of pulp chemistry and behavior was achieved by using kaolinite and Na-exchanged (swelling) smectite clay minerals, divalent metal ions (Ca(II), Mn(II)) as coagulants and anionic polyacrylamide copolymer (PAM A) and non-ionic

  18. Comparative studies of mycotoxin adsorption activities by clays and zeolitic minerals 

    E-print Network

    Green, Justin Lane

    1984-01-01

    processing. A variety of clays and zeolitic minerals were tested for their capacity to bind patulin, penicillic acid, ochratoxin A, deoxy- nivalenol and [1- C] deoxynivalenol. Toxin/clay solutions were analyzed in vitro via HPLC using a reverse phase.... . . . . Analyti c extract i on of [I- CJ deoxyni val enol. . . 55 Fi gure 16 17 18 Bulk purification of [1- C] deoxynivalenol. . Radiochromatogram of I. 1- Cj deoxynivalenol. . HPLC chromatogram of patulin. Page 66 84 19 Total ion chromatogram...

  19. Effects of aluminosilicate minerals in clay soil fractions on pore water hydroxide ion concentrations in soil/cement matrices 

    E-print Network

    Cook, Evan Russell

    1998-01-01

    between clay minerals and calcium hydroxide. Pozzolanic reactions between aluminosilicate minerals in soils and portiandite or calcium silicate hydrate, generated by cement hydration, may significantly reduce the hydroxide ion concentration in soi...

  20. Atom exchange between aqueous Fe(II) and structural Fe in clay minerals.

    PubMed

    Neumann, Anke; Wu, Lingling; Li, Weiqiang; Beard, Brian L; Johnson, Clark M; Rosso, Kevin M; Frierdich, Andrew J; Scherer, Michelle M

    2015-03-01

    Due to their stability toward reductive dissolution, Fe-bearing clay minerals are viewed as a renewable source of Fe redox activity in diverse environments. Recent findings of interfacial electron transfer between aqueous Fe(II) and structural Fe in clay minerals and electron conduction in octahedral sheets of nontronite, however, raise the question whether Fe interaction with clay minerals is more dynamic than previously thought. Here, we use an enriched isotope tracer approach to simultaneously trace Fe atom movement from the aqueous phase to the solid ((57)Fe) and from the solid into the aqueous phase ((56)Fe). Over 6 months, we observed a significant decrease in aqueous (57)Fe isotope fraction, with a fast initial decrease which slowed after 3 days and stabilized after about 50 days. For the aqueous (56)Fe isotope fraction, we observed a similar but opposite trend, indicating that Fe atom movement had occurred in both directions: from the aqueous phase into the solid and from the solid into aqueous phase. We calculated that 5-20% of structural Fe in clay minerals NAu-1, NAu-2, and SWa-1 exchanged with aqueous Fe(II), which significantly exceeds the Fe atom layer exposed directly to solution. Calculations based on electron-hopping rates in nontronite suggest that the bulk conduction mechanism previously demonstrated for hematite1 and suggested as an explanation for the significant Fe atom exchange observed in goethite2 may be a plausible mechanism for Fe atom exchange in Fe-bearing clay minerals. Our finding of 5-20% Fe atom exchange in clay minerals indicates that we need to rethink how Fe mobility affects the macroscopic properties of Fe-bearing phyllosilicates and its role in Fe biogeochemical cycling, as well as its use in a variety of engineered applications, such as landfill liners and nuclear repositories. PMID:25671351

  1. Clay mineral diagenesis in Westwater Canyon sandstone member of Morrison Formation, San Juan basin, New Mexico

    SciTech Connect

    Crossey, L.J. (Univ. of New Mexico, Albuquerque (USA))

    1989-09-01

    The Westwater Canyon Sandstone Member and the Brushy Basin and Recapture Shale Members of the Morrison Formation are examined from core located on the southern flank of the San Juan basin, northwestern New Mexico. Clay mineralogy of fine-grained lithologies of the Westwater Canyon Sandstone Member is contrasted with that of coarse-grained lithologies. Two distinct mixed-layer clay populations are present: a high expandable mixed-layer illite/smectite associated with coarse-grained lithologies. Two distinct mixed-layer clay populations are present: a highly expandable mixed-layer illite/smectite associated with coarse-grained units (in addition to chlorite and kaolinite), and an illitic mixed-layer illite/smectite (in some cases ordered and accompanied by traces of chlorite) in the fine-grained units. The expandable component of the mixed-layer clay does not exhibit a trend with depth but is lithology dependent. Coarse-grained samples from the Westwater Canyon Sandstone Member contain numerous mudstone intraclasts. The clay mineralogy of selected clasts has been examined. These lithologic characteristics must be taken into account in interpreting clay mineral diagenesis within the Morrison Formation. Framework grain alternation within the Westwater Canyon Sandstone Member has been linked to lacustrine facies in the overlying Brushy Basin Shale Member. Authigenic clay minerals within the Westwater Canyon Sandstone Member may provide a record of downward-percolating lake fluids. Early diagenetic effects must be recognized in order to interpret the complete diagenetic history of the Westwater Canyon Sandstone Member.

  2. Clay and non-clay minerals in the pharmaceutical and cosmetic industries Part II. Active ingredients

    Microsoft Academic Search

    M. Isabel Carretero; Manuel Pozo

    2010-01-01

    A wide range and variety of minerals are used in the pharmaceutical industry as active ingredients. Such minerals may be administered either orally as antacids, gastrointestinal protectors, antidiarrhoeaics, osmotic oral laxatives, homeostatics, direct emetics, antianemics and mineral supplements, or parenterally as antianemics and homeostatics. They may also be used topically as antiseptics, disinfectants, dermatological protectors, anti-inflammatories, local anesthetics, keratolytic reducers

  3. Clay minerals and metal oxides strongly influence the structure of alkane-degrading microbial communities during soil maturation.

    PubMed

    Steinbach, Annelie; Schulz, Stefanie; Giebler, Julia; Schulz, Stephan; Pronk, Geertje J; Kögel-Knabner, Ingrid; Harms, Hauke; Wick, Lukas Y; Schloter, Michael

    2015-07-01

    Clay minerals, charcoal and metal oxides are essential parts of the soil matrix and strongly influence the formation of biogeochemical interfaces in soil. We investigated the role of these parental materials for the development of functional microbial guilds using the example of alkane-degrading bacteria harbouring the alkane monooxygenase gene (alkB) in artificial mixtures composed of different minerals and charcoal, sterile manure and a microbial inoculum extracted from an agricultural soil. We followed changes in abundance and community structure of alkane-degrading microbial communities after 3 and 12 months of soil maturation and in response to a subsequent 2-week plant litter addition. During maturation we observed an overall increasing divergence in community composition. The impact of metal oxides on alkane-degrading community structure increased during soil maturation, whereas the charcoal impact decreased from 3 to 12 months. Among the clay minerals illite influenced the community structure of alkB-harbouring bacteria significantly, but not montmorillonite. The litter application induced strong community shifts in soils, maturated for 12 months, towards functional guilds typical for younger maturation stages pointing to a resilience of the alkane-degradation function potentially fostered by an extant 'seed bank'. PMID:25535940

  4. EUROPIUM RETENTION ONTO CLAY MINERALS FROM 25 TO 150C: EXPERIMENTAL MEASUREMENTS, SPECTROSCOPIC FEATURES AND SORPTION MODELLING.

    E-print Network

    Paris-Sud XI, Université de

    1 EUROPIUM RETENTION ONTO CLAY MINERALS FROM 25 TO 150°C: EXPERIMENTAL MEASUREMENTS, SPECTROSCOPIC.Tertre@univ-lille1.fr Keywords: europium, sorption, clays, experimental, temperature, Time-Resolved Laser was investigated up to 150°C. The clays were purified samples, saturated with Na in the case of montmorillonite

  5. Toxicological evaluation and metal bioavailability in pregnant rats following exposure to clay minerals in the diet.

    PubMed

    Wiles, Melinda; Huebner, Henry; Afriyie-Gyawu, Evans; Taylor, Robert; Bratton, Gerald; Phillips, Timothy

    2004-06-11

    Silicate clays are frequently added to animal feeds to bind and reduce the bioavailability of mycotoxins in the gastrointestinal tract. However, the bioavailability of trace metals in these clay feed additives has not been thoroughly investigated. Clays that act nonselectively may interact with nutrients, minerals, and other feedborne chemicals to pose significant hidden risks. In this study, a calcium montmorillonite clay (Novasil Plus, NSP) commonly used as an enterosorbent for aflatoxins and a sodium montmorillonite clay (Swy-2) (Source Clay Minerals Repository, Columbia, MO) were examined. Clays were supplemented in the balanced diet of Sprague-Dawley rats during pregnancy at a level of 2% (w/w). Evaluations of toxicity were performed on gestation d 16 and included maternal body weights, maternal feed intakes, litter weights, and embryonic resorptions. Liver, kidneys, tibia, brain, uterus, pooled placentas, and pooled embryonic mass were collected and weighed. Tissues were lyophilized and neutron activation analysis (NAA) was performed. Elements considered by NAA included Al, Ba, Br, Ca, Ce, Co, Cr, Cs, Cu, Dy, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Nd, Ni, Rb, S, Sb, Sc, Se, Sm, Sr, Ta, Tb, Te, Th, Ti, Tl, U, V, Yb, Zn, and Zr. Inductively coupled plasma-mass spectroscopy further confirmed that Al was below detection limits (<0.5 ppm) in the brain. Animals supplemented with either NSP or Swy-2 were similar to controls with respect to toxicity evaluations and metal analysis, with the exception of decreased brain Rb following clay supplementation. Overall, the results of this study suggest that neither NSP nor Swy-2, at relatively high dietary concentrations, influences mineral uptake or utilization in the pregnant rat. PMID:15205041

  6. Reduction And Immobilization Of Hexavalent Chromium By Microbially Reduced Fe-bearing Clay Minerals

    SciTech Connect

    Bishop, Michael E.; Glasser, Paul; Dong, Hailiang; Arey, Bruce W.; Kovarik, Libor

    2014-05-15

    Hexavalent chromium (Cr6+) is a major contaminant in the environment. As a redox-sensitive element, the fate and toxicity of chromium is controlled by reduction-oxidation (redox) reactions. Previous research has shown the ability of structural Fe(II) in naturally present and chemically reduced clay minerals to reduce Cr6+ to Cr(III) as a way of immobilization and detoxification. However, it is still poorly known whether or not structural Fe(II) in biologically reduced clay minerals exhibits a similar reactivity and if so, what the kinetics and mechanisms of Cr6+ reduction are. The objective of this study was to determine the kinetics and possible mechanisms of Cr6+ reduction by structural Fe(II) in microbially reduced clay minerals and the nature of reduced Cr(III). Structural Fe(III) in nontronite (NAu-2), montmorillonite (SWy-2), chlorite (CCa-2), and clay-rich sediments from the Ringold Formation of the Hanford site of Washington State, USA was first bioreduced to Fe(II) by an iron-reducing bacterium Geobacter sulfurreducens with acetate as the sole electron donor and anthraquinone-2,6-disulfate (AQDS) as electron shuttle in synthetic groundwater (pH 7). Biogenic Fe(II) was then used to reduce aqueous Cr6+ at three different temperatures, 10°, 20°, and 30°C, in order to determine the temperature dependence of the redox reaction between Cr6+ and clay-Fe(II). The results showed that nontronite and montmorillonite were most effective in reducing aqueous Cr6+ at all three temperatures. In contrast, most Fe(II) in chlorite was not reactive towards Cr6+ reduction at 10°C, though at 30°C there was some reduction. For all the clay minerals, the ratio of total Fe(II) oxidized to Cr6+ reduced was close to the expected stoichiometric value of 3. Characterization of the Cr-clay reaction product with scanning electron microscopy with focused ion beam and transmission electron microscopy with electron energy loss spectroscopy revealed that reduced chromium was possibly in the form of sub-nanometer Cr2O3 in association with residual clay minerals as micro-aggregates. This textural association was expected to minimize the chance of Cr(III) reoxidation upon exposure to oxidants. These results are important for our understanding of how various clay minerals may be used to reductively immobilize the heavy metal contaminant Cr in the environment.

  7. Implications of Clay Mineral-RNA Interactions for the Origin of Life

    NASA Astrophysics Data System (ADS)

    Stephenson, J. D.; Ditzler, M. A.

    2014-12-01

    Due to its ability to both store information and catalyze reactions, RNA is considered by many to have been the dominant biopolymer at the origin of life. We are screening a large, random RNA population for catalytic activity in the presence and absence of prebiotically relevant clay minerals, to investigate the effect of RNA-clay mineral interactions on RNA function. There is an extensive precedent for screening RNA populations for enzymatic functions such as ligation, cleavage and binding in the laboratory. While several environmental parameters have been explored, previous screens have not considered geological interactions. This is surprising as the role of clay minerals has featured prominently in many origin of life theories. Recent empirical evidence demonstrating that clay minerals can adsorb and protect RNA molecules as well as catalyze RNA polymerization has specifically reinvigorated the proposed importance of clay mineral-RNA interactions. Although the identity of the first true biomolecules remains uncertain, interaction between emerging life and its geological environment appears inevitable. We therefore consider understanding the effect of geological-biological interactions to be of crucial importance when considering the earliest biopolymers at the origin of life. Our screens are from a random population of 10^14 unique random RNA sequences and are conducted with and without montmorillonite clay. We are screening for the ability of sequences to self cleave, one of the most basic enzymatic functions considered important to the earliest biopolymers. Our RNA function screens will therefore illuminate the effect of geological interactions at a crucial stage of early evolution.

  8. Measurement of clay surface areas by polyvinylpyrrolidone (PVP) sorption and its use for quantifying illite and smectite abundance

    USGS Publications Warehouse

    Blum, A.E.; Eberl, D.D.

    2004-01-01

    A new method has been developed for quantifying smectite abundance by sorbing polyvinylpyrrolidone (PVP) on smectite particles dispersed in aqueous solution. The sorption density of PVP-55K on a wide range of smectites, illites and kaolinites is ???0.99 mg/m2, which corresponds to ???0.72 g of PVP-55K per gram of montmorillonite. Polyvinylpyrrolidone sorption on smectites is independent of layer charge and solution pH. PVP sorption on Si02, Fe 2O3 and ZnO normalized to the BET surface area is similar to the sorption densities on smectites. ??-Al 2O3, amorphous Al(OH)3 and gibbsite have no PVP sorption over a wide range of pH, and sorption of PVP by organics is minimal. The insensitivity of PVP sorption densities to mineral layer charge, solution pH and mineral surface charge indicates that PVP sorption is not localized at charged sites, but is controlled by more broadly distributed sorption mechanisms such as Van der Waals' interactions and/or hydrogen bonding. Smectites have very large surface areas when dispersed as single unit-cell-thick particles (???725 m2/g) and usually dominate the total surface areas of natural samples in which smectites are present. In this case, smectite abundance is directly proportional to PVP sorption. In some cases, however, the accurate quantification of smectite abundance by PVP sorption may require minor corrections for PVP uptake by other phases, principally illite and kaolinite. Quantitative XRD can be combined with PVP uptake measurements to uniquely determine the smectite concentration in such sample. ?? 2004, The Clay Minerals Society.

  9. Rare earth distributions in clay minerals and in the clay-sized fraction of the Lower Permian Havensville and Eskridge shales of Kansas and Oklahoma

    Microsoft Academic Search

    Robert L. Cullers; Sambhudas Chaudhuri; Bill Arnold; Moon Lee; Carlton W. Wolf Jr.

    1975-01-01

    The REE (rare earth element) content of a wide variety of clay mineral groups have been analyzed using radiochemical neutron activation and have been found to be quite variable in absolute REE content (range of REE = 5.4-1732) and less variable in relative REE content (range of chondritenormalized La \\/ Lu = 0.9-16.5). The variable REE content of the clay

  10. Removal of Prymnesium parvum (Haptophyceae) and its toxins using clay minerals

    Microsoft Academic Search

    Mario R. Sengco; Johannes A. Hagström; Edna Granéli; Donald M. Andersona

    2005-01-01

    Laboratory experiments were conducted to examine the ability of several clay minerals from Sweden to remove the fish-killing microalga, Prymnesium parvum Carter, from suspension. In their commercial form (i.e. after incineration at 400°C), seawater slurries (salinity = 26) of the three minerals tested were generally ineffective at removing P. parvum from culture within a range of 0.01 to 0.50g\\/L, and

  11. Experimental Constraints on Microbial Liberation of Structural Iron from Common Clay Minerals in Marine Sediments

    NASA Astrophysics Data System (ADS)

    Metcalfe, K. S.; Gaines, R. R.; Trang, J.; Scott, S. W.; Crane, E. J.; Lackey, J.; Prokopenko, M. G.; Berelson, W.

    2013-12-01

    Iron is a limiting nutrient in many marine settings. The marine Fe-cycle is complex because Fe may be used as an electron donor or acceptor and cycled many times before ultimate burial in sediments. Thus, the availability of iron plays a large role in the marine carbon cycle, influencing not only the extent of primary productivity but also the oxidation of organic matter in sediments. The primary constituents of marine sediments are clay minerals, which commonly contain lattice-bound Fe in octahedral sites. In marine settings, the pool of Fe bound within silicate mineral lattices has long been considered reactive only over long timescales, and thus non-bioavailable. In vitro experimental evidence has shown that lab cultures of Fe-reducing bacteria are able to utilize structurally-bound Fe (III) from the crystal lattice of nontronite, an uncommon but particularly Fe-rich (> 12 wt.%) smectite. Importantly, this process is capable of liberating Fe (II) to solution, where it is available to biotic processes as an electron donor. In order to constrain the capacity of naturally-occurring marine bacteria to liberate structurally-coordinated Fe from the lattices of common clay minerals, we exposed a suite of 16 different clay minerals (0.8-13.9 wt.% Fe) to lab cultures of known Fe-reducer S. onenidensis MR-1 and to a natural consortium of Fe-reducing microbes from the San Pedro and Santa Monica Basins over timescales ranging from 7-120 days. Clay minerals were treated with Na-dithionite to extract surface-bound Fe prior to exposure. Crystallographic data and direct measurements of Fe in solution demonstrate the release of structural Fe from all clay minerals analyzed. Neoformation of illite and amorphous quartz were observed. The array of clay minerals and microbes used in this experiment complement past findings and suggest that common clay minerals may represent a large and previously unrecognized pool of bioavailable Fe in the world ocean that contributes significantly to biogeochemical cycling of Fe and C.

  12. Diagenesis of clay minerals from early Eocene shales of Texas

    E-print Network

    Whynot, John David

    1983-01-01

    reaction, octahedral Al in smectites act as electron accep- tors promoting free radial formation and subsequent decarboxylation. In the second reaction, smectites donate protons through dissociation of interlayer water promoting carbonium ion reactions...-Layer Clays Other Temperature ('C) Early Decarboxylation Expulsion of pore waters and indigenous hydrocarbons 80 60 M'ddle Cracking 60 Water available for hydrocarbon migration 50-60 30-40 Discrete Smectite 90 absent. Regular interstratification...

  13. Values of Mineral Modulus of Clay Manika Prasad, Ronny Hofmann, Mike Batzle, Colorado School of Mines; M. Kopycinska-Mller, U. Rabe, and

    E-print Network

    Values of Mineral Modulus of Clay Manika Prasad, Ronny Hofmann, Mike Batzle, Colorado School formations is altered by the presence of clay minerals. Knowledge about the elastic properties of clay is therefore essential for the interpretation and modeling of the seismic response of clay- bearing formations

  14. Effect of purity on adsorption capacities of a Mars-like clay mineral at different pressures

    NASA Technical Reports Server (NTRS)

    Jenkins, Traci; Mcdoniel, Bridgett; Bustin, Roberta; Allton, Judith H.

    1992-01-01

    There has been considerable interest in adsorption of carbon dioxide on Marslike clay minerals. Some estimates of the carbon dioxide reservoir capacity of the martian regolith were calculated from the amount of carbon dioxide adsorbed on the ironrich smectite nontronite under martian conditions. The adsorption capacity of pure nontronite could place upper limits on the regolith carbon dioxide reservoir, both at present martian atmospheric pressure and at the postulated higher pressures required to permit liquid water on the surface. Adsorption of carbon dioxide on a Clay Mineral Society standard containing nontronite was studied over a wide range of pressures in the absence of water. Similar experiments were conducted on the pure nontronite extracted from the natural sample. Heating curves were obtained to help characterize and determine the purity of the clay sample.

  15. Deuterium and oxygen-18 correlation: Clay minerals and hydroxides in Quaternary soils compared to meteoric waters

    Microsoft Academic Search

    James R. Lawrence; Hugh P. Taylor Jr.

    1971-01-01

    D and O 18 of clay minerals and hydroxides in Quaternary soils of the United States correlate directly with D and O 18 of corresponding present-day meteoric waters. Samples from Montana and Idaho are much lower in both D and O 18 than those from coastal areas. The Hawaiian and Gulf Coast samples are highest in D and O 18

  16. Modeling selenite adsorption envelopes on oxides, clay minerals, and soils using the triple layer model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selenite adsorption behavior was investigated on amorphous aluminum and iron oxides, clay minerals: kaolinite, montmorillonite, and illite, and 45 surface and subsurface soil samples from the Southwestern and Midwestern regions of the USA as a function of solution pH. Selenite adsorption decreased ...

  17. Frictional properties of the shallow Nankai Trough accretionary sediments dependent on the content of clay minerals

    NASA Astrophysics Data System (ADS)

    Takahashi, Miki; Azuma, Shuhei; Ito, Hidenori; Kanagawa, Kyuichi; Inoue, Atsuyuki

    2014-12-01

    We conducted triaxial friction experiments on the shallow Nankai Trough accretionary sediments at confining pressures, pore water pressures, temperatures close to their in situ conditions, and axial displacement rates ( V axial) changed stepwise among 0.1, 1, and 10µm/s. The results revealed that their frictional properties change systematically according to the content of clay minerals, smectite in particular. The steady-state friction coefficient ( ? ss) at V axial = 1µm/s decreases with increasing clay mineral content, shown in weight percent, from 0.82 for a sandstone sample (6 wt%), through 0.71 for a tuff sample (?17 wt%), and 0.53 to 0.56 for siltstone samples (29 to 34 wt%), to 0.25 for a claystone sample (42 wt%). Slip-dependent frictional behavior changes accordingly from slip hardening for the sandstone sample, through quasi steady-state slip for the tuff and siltstone samples, to distinct slip weakening for the claystone sample. Although all samples exhibit velocity-strengthening behavior upon stepwise changes in sliding velocity, the ratio of the ( a - b) value to the velocity dependence of steady-state friction (? ? ss/?ln V sliding) decreases with increasing clay mineral content, which implies that the friction component decreases while the flow component increases accordingly. Thus, faulting in the shallow Nankai Trough accretionary prism is likely controlled by the clay mineral content, in particular the smectite content, in the sediments as well as in the fault zones.

  18. High resolution structural investigation of synthetic and natural 2:1 clay-mineral assemblages using

    E-print Network

    Barnes, Sarah-Jane

    using advanced sample preparation and electron microscopy imaging techniques Dirk Schumann Department this thesis project was completed; my wife Katrin Schumann, mother Kerstin J. Schumann, father Bernd H-fringe images. As these clay minerals are interpreted to replicate by template-catalyzed polymerization

  19. INFLUENCE OF TEMPERATURE ON NICKEL SORPTION ON CLAY MINERAL AND OXIDE SURFACES. K. G. Scheckel1

    E-print Network

    Sparks, Donald L.

    INFLUENCE OF TEMPERATURE ON NICKEL SORPTION ON CLAY MINERAL AND OXIDE SURFACES. K. G. Scheckel1- mation of metal precipitates. However, the influence of temperature on the kinetic formation of these metal pre- cipitates has not been studied. The effect of temperature on reaction rates is well known

  20. Minerals and clay minerals assemblages in organic-rich facies: the case study of the Sinemurian-Pliensbachian carbonate deposits of the western Lusitanian Basin (Portugal)

    NASA Astrophysics Data System (ADS)

    Caniço, Ana; Duarte, Luís V.; Silva, Ricardo L.; Rocha, Fernando; Graciano Mendonça Filho, João

    2015-04-01

    The uppermost Sinemurian-Pliensbachian series of the western part of the Lusitanian Basin is composed by hemipelagic carbonates particularly enriched in organic matter. Great part of this succession, considered to be one of the most important potential source rock intervals of Portugal, crops out in the S. Pedro de Moel and Peniche sectors, belonging to the Água de Madeiros and Vale das Fontes formations. In this study, supported by a detailed and integrated stratigraphic framework, we analyzed 98 marly samples (whole-rock mineralogy and clay minerals assemblages) from the aforementioned formations in the S. Pedro de Moel and Peniche sectors. X-ray Diffraction analysis followed the standard procedures and the semi-quantification of the different mineral phases was calculated using MacDiff 4.2.6. The goals of this work are to demonstrate the vertical variability of the mineral composition of these two units and investigate the relationship between the clay minerals assemblages and the content in organic matter (Total organic carbon: TOC). Besides the abundance of calcite and phyllosilicates, whole-rock mineralogy revealed the presence of quartz, potassium feldspar, dolomite, and pyrite (trace amounts). Other minerals like anhydrite, barite and gypsum occur sporadically. The clay minerals assemblages are dominated by illite+illite/smectite mixed-layers (minimum of 59%), always associated with kaolinite (maximum of 37%) and chlorite (maximum of 25%); sporadically smectite occurs in trace amounts. Generally, high TOC levels (i.e., black shale facies with TOC reaching up to 22 wt.% in both units, see Duarte et al., 2010), show a major increase in chlorite and kaolinite (lower values of illite+illite/smectite mixed layers). A kaolinite enrichment is also observed just above the Sinemurian-Pliensbachian boundary (base of Praia da Pedra Lisa Member of Água de Madeiros Formation; values varying between 30 and 37%). This event is associated with a second-order regressive phase, and marks the disappearance of the organic-rich facies and increase of carbonate sedimentation. This enrichment was likely favored by the development of more humid conditions at the Sinemurian-Pliensbachian transition. References Duarte, L.V., Silva, R.L., Oliveira, L.C.V., Comas-Rengifo, M.J., Silva, F. 2010. Organic-rich facies in the Sinemurian and Pliensbachian of the Lusitanian Basin, Portugal: Total Organic Carbon distribution and relation to transgressive-regressive facies cycles. Geologica Acta 8, 325-340.

  1. Stressed swelling clay Arpita Pal Bathija1

    E-print Network

    Liang, Haiyi

    Stressed swelling clay Arpita Pal Bathija1 , Haiyi Liang2 , Ning Lu3 , Manika Prasad4 , and Michael Lee Batzle1 ABSTRACT Clay minerals are present in most sedimentary rocks. They find applicability- spite their abundance and use, swelling of clays under stress has not received enough scientific

  2. The MS-Q Force Field for Clay Minerals: Application to Oil Production Sungu Hwang, Mario Blanco, Ersan Demiralp, Tahir Cagin, and William A. Goddard, III*

    E-print Network

    Çagin, Tahir

    The MS-Q Force Field for Clay Minerals: Application to Oil Production Sungu Hwang, Mario Blanco to model kaolinite and pyrophyllite clay minerals and their interactions with representative organic molecules. The MS-Q FF reproduces the structural parameters for these clay minerals and gives accurate

  3. Kinetics of Ion Exchange on Clay Minerals and Soil: II. Elucidation of Rate-limiting Steps1 R. A. OGWADA ANDD. L. SPARKS2

    E-print Network

    Sparks, Donald L.

    Kinetics of Ion Exchange on Clay Minerals and Soil: II. Elucidation of Rate-limiting Steps1 R. A of this study was to elucidate the rate- limiting steps for K+ adsorption on the clay minerals and soil. We.L. Sparks. 1986. Kinetics of ion exchange on clay minerals and soil: II. Elucidation of rate-limiting steps

  4. Kinetics of Ion Exchange on Clay Minerals and Soil: I. Evaluation of Methods1 R. A. OGWADA AND D. L. SPARKS2

    E-print Network

    Sparks, Donald L.

    Kinetics of Ion Exchange on Clay Minerals and Soil: I. Evaluation of Methods1 R. A. OGWADA AND D. L,vermiculite. Ogwada, R.A., and D.L. Sparks. 1986. Kinetics of ion exchangeon clay minerals and soil: I. Evaluation displacement or flow techniques to investigate kinetics of ion exchange on soils and clay minerals (Sparks

  5. Neocrystallization, fabrics and age of clay minerals from an exposure of the Moab Fault, Utah

    USGS Publications Warehouse

    Solum, J.G.; van der Pluijm, B.A.; Peacor, D.R.

    2005-01-01

    Pronounced changes in clay mineral assemblages are preserved along the Moab Fault (Utah). Gouge is enriched up to ???40% in 1Md illite relative to protolith, whereas altered protolith in the damage zone is enriched ???40% in illite-smectite relative to gouge and up to ???50% relative to protolith. These mineralogical changes indicate that clay gouge is formed not solely through mechanical incorporation of protolith, but also through fault-related authigenesis. The timing of mineralization is determined using 40Ar/39Ar dating of size fractions of fault rocks with varying detrital and authigenic clay content. We applied Ar dating of illite-smectite samples, as well as a newer approach that uses illite polytypes. Our analysis yields overlapping, early Paleocene ages for neoformed (1Md) gouge illite (63??2 Ma) and illite-smectite in the damage zone (60??2 Ma), which are compatible with results elsewhere. These ages represent the latest period of major fault motion, and demonstrate that the fault fabrics are not the result of recent alteration. The clay fabrics in fault rocks are poorly developed, indicating that fluids were not confined to the fault zone by preferentially oriented clays; rather we propose that fluids in the illite-rich gouge were isolated by adjacent lower permeability, illite-smectite-bearing rocks in the damage zone. ?? 2005 Elsevier Ltd. All rights reserved.

  6. Genesis of clay mineral assemblages and micropaleoclimatic implications in the Tertiary Powder River Basin, Wyoming

    SciTech Connect

    Flores, R.M.; Weaver, J.N. (Geological Survey, Denver, CO (USA)); Bossiroy, D.; Thorez, J. (Liege State Univ. (Belgium))

    1990-05-01

    An x-ray diffraction (XRD) study was undertaken on the clay mineralogy of the early Tertiary coal-bearing sequences of the Powder River basin. The vertical and lateral distribution of alternating fluvial conglomerates, sandstones, mudstones, shales, coals, and paleosols reveals a transition from alluvial fans along the basin margin to an alluvial plain and peat bogs basinward. Samples included unweathered shales and mudstones from a borehole and a variety of corresponding surface outcrop samples of Cambrian to Eocene age. Samples older than Tertiary were collected along the basin margin specifically to determine the potential source of parent material during Tertiary sedimentation. XRD analyses were performed on the <2-{mu}m fraction prepared as oriented aggregates. To investigate the materials in their natural state, no chemical pre-treatments the authors applied before the analysis. A series of specific post-treatments, consisting of catonic saturation (Li+, K+), a solution with polyalcohols, heating, acid attack and hydrazine saturation was selectively applied. These post-treatments permit a good discrimination between the mimetic clay minerals such as smectite and illite-smectite mixed layers that constitute the bulk of the clay fraction in the Tertiary rocks. When analyzed only using routine XRD, these swelling minerals are apparently uniformly distributed in the fluvial sedimentary rocks and are better interpreted as a single smectitic population. However, the post-treatments clearly differentiate both qualitatively and quantitatively this smectitic stock. Other clays include illite and kaolinite, which have different degrees of crystallinity, and minor interstratified clays (i.e., illite-chlorite, chlorite-smectite). The clay minerals in pre-Tertiary (and pedogenic) materials are different from those in the Tertiary rocks.

  7. Clay minerals in primitive meteorites and interplanetary dust 1

    NASA Technical Reports Server (NTRS)

    Zolensky, M. E.; Keller, L. P.

    1991-01-01

    Many meteorites and interplanetary dust particles (IDPs) with primitive compositions contain significant amounts of phyllosilicate minerals, which are generally interpreted as evidence of protoplanetary aqueous alteration at an early period of the solar system. These meteorites are chondrites (near solar composition) of the carbonaceous and ordinary varieties. The former are subdivided (according to bulk composition and petrology) into CI, CM, CV, CO, CR, and ungrouped classes. IDPs are extraterrestrial particulates, collected in stratosphere, which have chemical compositions indicative of a primitive origin; they are typically distinct from the primitive meteorites. Characterization of phyllosilicates in these materials is a high priority because of the important physico-chemical information they hold. The most common phyllosilicates present in chondritic extraterrestrial materials are serpentine-group minerals, smectites, and micas. We discuss these phyllosilicates and describe the interpretation of their occurrence in meteorites and IDPs and what this indicates about history of their parent bodies, which are probably the hydrous asteroids.

  8. Bioremediating oil spills in nutrient poor ocean waters using fertilized clay mineral flakes: some experimental constraints.

    PubMed

    Warr, Laurence N; Friese, André; Schwarz, Florian; Schauer, Frieder; Portier, Ralph J; Basirico, Laura M; Olson, Gregory M

    2013-01-01

    Much oil spill research has focused on fertilizing hydrocarbon oxidising bacteria, but a primary limitation is the rapid dilution of additives in open waters. A new technique is presented for bioremediation by adding nutrient amendments to the oil spill using thin filmed minerals comprised largely of Fullers Earth clay. Together with adsorbed N and P fertilizers, filming additives, and organoclay, clay flakes can be engineered to float on seawater, attach to the oil, and slowly release contained nutrients. Our laboratory experiments of microbial activity on weathered source oil from the Deepwater Horizon spill in the Gulf of Mexico show fertilized clay treatment significantly enhanced bacterial respiration and consumption of alkanes compared to untreated oil-in-water conditions and reacted faster than straight fertilization. Whereas a major portion (up to 98%) of the alkane content was removed during the 1 month period of experimentation by fertilized clay flake interaction; the reduced concentration of polyaromatic hydrocarbons was not significantly different from the non-clay bearing samples. Such clay flake treatment could offer a way to more effectively apply the fertilizer to the spill in open nutrient poor waters and thus significantly reduce the extent and duration of marine oil spills, but this method is not expected to impact hydrocarbon toxicity. PMID:23864952

  9. Influence of soil properties on the toxicity of TiO? nanoparticles on carbon mineralization and bacterial abundance.

    PubMed

    Simonin, Marie; Guyonnet, Julien P; Martins, Jean M F; Ginot, Morgane; Richaume, Agnès

    2015-02-11

    Information regarding the impact of low concentration of engineered nanoparticles on soil microbial communities is currently limited and the importance of soil characteristics is often neglected in ecological risk assessment. To evaluate the impact of TiO2 nanoparticles (NPs) on soil microbial communities (measured on bacterial abundance and carbon mineralization activity), 6 agricultural soils exhibiting contrasted textures and organic matter contents were exposed for 90 days to a low environmentally relevant concentration or to an accidental spiking of TiO2-NPs (1 and 500mgkg(-1) dry soil, respectively) in microcosms. In most soils, TiO2-NPs did not impact the activity and abundance of microbial communities, except in the silty-clay soil (high OM) where C-mineralization was significantly lowered, even with the low NPs concentration. Our results suggest that TiO2-NPs toxicity does not depend on soil texture but likely on pH and OM content. We characterized TiO2-NPs aggregation and zeta potential in soil solutions, in order to explain the difference of TiO2-NPs effects on soil C-mineralization. Zeta potential and aggregation of TiO2-NPs in the silty-clay (high OM) soil solution lead to a lower stability of TiO2-NP-aggregates than in the other soils. Further experiments would be necessary to evaluate the relationship between TiO2-NPs stability and toxicity in the soil. PMID:25464292

  10. Iron-rich clay minerals on Mars - Potential sources or sinks for hydrogen and indicators of hydrogen loss over time

    NASA Technical Reports Server (NTRS)

    Burt, D. M.

    1989-01-01

    Although direct evidence is lacking, indirect evidence suggests that iron-rich clay minerals or poorly-ordered chemical equivalents are widespread on the Martian surface. Such clays can act as sources or sinks for hydrogen ('hydrogen sponges'). Ferrous clays can lose hydrogen and ferric clays gain it by the coupled substitution Fe(3+)O(Fe(2+)OH)-1, equivalent to minus atomic H. This 'oxy-clay' substitution involves only proton and electron migration through the crystal structure, and therefore occurs nondestructively and reversibly, at relatively low temperatures. The reversible, low-temperature nature of this reaction contrasts with the irreversible nature of destructive dehydroxylation (H2O loss) suffered by clays heated to high temperatures. In theory, metastable ferric oxy-clays formed by dehydrogenation of ferrous clays over geologic time could, if exposed to water vapor, extract the hydrogen from it, releasing oxygen.

  11. Clay mineral continental amplifier for marine carbon sequestration in a greenhouse ocean

    PubMed Central

    Kennedy, Martin J.; Wagner, Thomas

    2011-01-01

    The majority of carbon sequestration at the Earth’s surface occurs in marine continental margin settings within fine-grained sediments whose mineral properties are a function of continental climatic conditions. We report very high mineral surface area (MSA) values of 300 and 570 m2 g in Late Cretaceous black shales from Ocean Drilling Program site 959 of the Deep Ivorian Basin that vary on subcentennial time scales corresponding with abrupt increases from approximately 3 to approximately 18% total organic carbon (TOC). The observed MSA changes with TOC across multiple scales of variability and on a sample-by-sample basis (centimeter scale), provides a rigorous test of a hypothesized influence on organic carbon burial by detrital clay mineral controlled MSA. Changes in TOC also correspond with geochemical and sedimentological evidence for water column anoxia. Bioturbated intervals show a lower organic carbon loading on mineral surface area of 0.1 mg-OC m-2 when compared to 0.4 mg-OC m-2 for laminated and sulfidic sediments. Although either anoxia or mineral surface protection may be capable of producing TOC of < 5%, when brought together they produced the very high TOC (10–18%) apparent in these sediments. This nonlinear response in carbon burial resulted from minor precession-driven changes of continental climate influencing clay mineral properties and runoff from the African continent. This study identifies a previously unrecognized land–sea connection among continental weathering, clay mineral production, and anoxia and a nonlinear effect on marine carbon sequestration during the Coniacian-Santonian Oceanic Anoxic Event 3 in the tropical eastern Atlantic. PMID:21576498

  12. Reactive Clay Minerals in a land use sequence of disturbed soils of the Belgian Loam Belt

    NASA Astrophysics Data System (ADS)

    Barao, Lucia; Vandevenne, Floor; Ronchi, Benedicta; Meire, Patrick; Govers, Gerard; Struyf, Eric

    2014-05-01

    Clay minerals play a key role in soil biogeochemistry. They can stabilize organic matter, improve water storage, increase cation exchange capacity of the soil (CEC) and lower nutrient leaching. Phytoliths - the biogenic silica bodies (BSi) deposited in cell walls of plants - are important Si pools in soil horizons due to their higher solubility compared to minerals. They provide the source of Si for plant uptake in short time scales, as litter dissolves within soils. In a recent study, we analyzed the BSi pool differences across a set of different land uses (forests, pastures, croplands) in 6 long-term disturbed (multiple centuries) soil sites in the Belgium Loam Belt. Results from a simultaneous chemical extraction in 0.5M NaOH of Si and Al, showed that soils were depleted in the BSi pool while showing high levels of reactive secondary clay minerals, mainly in the deeper horizons and especially in the forests and the croplands. During the extraction, clays were similar in reactivity to the biogenic pool of phytoliths. In order to study the kinetics in a more natural environment, batch dissolution experiments were conducted. Samples from different soil depths for each land use site (0.5 g) were mixed with 0.5 L of demineralised water modified to pH 4, 7 and 10. Subsamples of 2 ml were taken during 3 months. In the end of the period, results for pH 7 showed that in the pastures, where reactive clays were almost absent, the ratio Si/RSi (defined as the Si concentration in the end of the batch experiment divided by the reactive silica extracted from the soil with the alkaline extraction) was lower than 0.005%. The same ratio was higher in the mineral horizons of forests (Si/RSi>0.01%) and croplands (0.005% < Si/RSi <0.01%) where clay minerals were the dominant fraction. These preliminary results highlight the clay minerals' strong potential for Si mobilization. More attention should be paid to this important fraction as it can contribute strongly to Si availability, in close competition with phytoliths and other soluble amorphous Si forms, strongly interfering with frequently applied methods to quantify biogenic Si in soils.

  13. Aqueous dissolution, solubilities and thermodynamic stabilities of common aluminosilicate clay minerals: Kaolinite and smectites

    USGS Publications Warehouse

    May, Howard M.; Klnniburgh, D.G.; Helmke, P.A.; Jackson, M.L.

    1986-01-01

    Determinations of the aqueous solubilities of kaolinite at pH 4, and of five smectite minerals in suspensions set between pH 5 and 8, were undertaken with mineral suspensions adjusted to approach equilibrium from over- and undersaturation. After 1,237 days, Dry Branch, Georgia kaolinite suspensions attained equilibrium solubility with respect to the kaolinite, for which Keq = (2.72 ?? 0.35) ?? 107. The experimentally determined Gibbs free energy of formation (??Gf,2980) for the kaolinite is -3,789.51 ?? 6.60 kj mol-1. Equilibrium solubilities could not be determined for the smectites because the composition of the solution phase in the smectite suspensions appeared to be controlled by the formation of gibbsite or amorphous aluminum hydroxide and not by the smectites, preventing attempts to determine valid ??Gf0 values for these complex aluminosilicate clay minerals. Reported solubility-based ??Gf0 determinations for smectites and other variable composition aluminosilicate clay minerals are shown to be invalid because of experimental deficiencies and of conceptual flaws arising from the nature of the minerals themselves. Because of the variable composition of smectites and similar minerals, it is concluded that reliable equilibrium solubilities and solubility-derived ??Gf0 values can neither be rigorously determined by conventional experimental procedures, nor applied in equilibriabased models of smectite-water interactions. ?? 1986.

  14. Adsorption of Pesticides and Their Biodegraded Products on Clay Minerals and Soils

    Microsoft Academic Search

    Yuichi Fushiwaki; Kohei Uranob

    2001-01-01

    Adsorption isotherms of 10 pesticides and their biodegradation intermediates on clay minerals and soils were investigated to predict the fate of pesticides in the environment. The adsorption isotherms were expressed by the Freundlich isotherm equation. Penta- chloronitrobenzene, 2,4,6-trichlorophenyl-4'-nitro- phenylether, and various intermediates were highly adsorbed on soils, although isoprothiolane was only slightly adsorbed. The adsorbabilities of pesticides on ando soil,

  15. Clay minerals from Weichselian glaciolimnic sediments of the S?popolska Plain (NE Poland)

    NASA Astrophysics Data System (ADS)

    Dlugosz, Jacek; Orzechowski, Miroslaw; Kobierski, Miroslaw; Smolczynski, Slawomir; Zamorski, Ryszard

    2009-06-01

    Glaciolimnic deposits sampled from three sedimentation reservoirs located on the S?popolska Plain (northeastern Poland) were investigated. The material under study was deposited in the recession phase of the Pomeranian phase of Vistula (Weichselian) glaciation. The clay fraction was separated by centrifugation after preparation according to Jackson. Mineralogical investigations were done by X-ray diffraction. The analysed deposits had a similar complex composition of clay minerals. The main components were illites mixed with the illite/smectite mineral with percentages < 10 % S. Another part were minerals of the illite/smectite type which had differentiated content of smectite layers (mainly 80-90 % S). There were also chlorite minerals, probably as mixed layer minerals of the chlorite/vermiculite type or HIV with a negligible amount of chlorite layers. The results indicated that all the deposits were of the same age as well as similar deposited material and the samples are different from typical Pomeranian till and typical limnic material of the same age. Small differences observed among the deposits of specific sedimentation reservoirs were probably the result of later processes.

  16. The First X-ray Diffraction Patterns of Clay Minerals from Gale Crater

    NASA Astrophysics Data System (ADS)

    Bristow, T.; Blake, D.; Bish, D. L.; Vaniman, D.; Ming, D. W.; Morris, R. V.; Chipera, S.; Rampe, E. B.; Farmer, J. D.; Treiman, A. H.; Downs, R.; Morrison, S.; Achilles, C.; Des Marais, D. J.; Crisp, J. A.; Sarrazin, P.; Morookian, J.; Grotzinger, J. P.; Team, M.

    2013-12-01

    The Mars Science Laboratory (MSL) Rover, Curiosity spent ~150 sols at Yellowknife Bay (YKB) studying a section of fluvio-lacustrine sedimentary rocks (with potential indications of volcanic influence), informally known as the Yellowknife Bay formation. YKB lies in a distal region of the Peace Vallis alluvial fan, which extends from the northern rim of Gale Crater toward the dune field at the base of Mt Sharp. Sedimentological and stratigraphic observations are consistent with the Yellowknife Bay formation being part of a distal fan deposit, which could be as young as middle Hesperian to even early Amazonian in age (~3.5 to 2.5 Ga). The Yellowknife Bay formation hosts a unit of mudstone called the Sheepbed member. Curiosity obtained powdered rock samples from two drill holes in the Sheepbed Member, named John Klein and Cumberland, and delivered them to instruments in Curiosity. Data from CheMin, a combined X-ray diffraction (XRD)/X-ray fluorescence instrument (XRF), has allowed detailed mineralogical analysis of mudstone powders revealing a clay mineral component of ~20 wt.% in each sample. The clay minerals are important indicators of paleoenvironmental conditions and sensitive recorders of post-depositional alteration processes. The XRD pattern of John Klein reveals a 02l band consistent with a trioctahedral phyllosilicate. A broad peak at ~10A with a slight inflexion at ~12A indicates the presence of 2:1 type clay minerals in the John Klein sample. The trioctahedral nature of the clay minerals, breadth of the basal reflection, and presence of a minor component with larger basal spacing suggests that John Klein contains a trioctahedral smectite (probably saponite), whose interlayer is largely collapsed because of the low-humidity conditions. The XRD patterns show no evidence of corrensite (mixed-layer chlorite/smectite) or chlorite, which are typical diagenetic products of trioctahedral smectites when subjected to burial and heating >60°C in the presence of water. Given estimated geothermal gradients on Mars temperatures <60 °C might still be consistent with (but do not require) moderate burial. However, our ability to identify interstratified minerals is greatly limited by the lack of access to traditional treatments methods used in the lab (e.g., ethylene glycol solvation). Our preferred explanation for the origin of trioctahedral smectites in Sheepbed mudstone is in situ production via reaction of olivine, water and Si-bearing amorphous material, an important mudstone component detected by XRD. Elevated levels of magnetite in the Sheepbed and the trioctahedral monomineralic nature of the clay minerals support this model. These observations, combined with previous studies of olivine stability, support the persistence of circum-neutral hydrous conditions for thousands of years at YKB.

  17. Clay minerals as proxies of the late Quaternary East Asian monsoon evolution in the South China Sea revisited

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Li, X.; He, Z.; Colin, C.; Zhao, Y.

    2012-12-01

    Clay minerals have a significant role in sedimentation and paleoenvironment studies of the South China Sea. Many previous studies showed that the time series variation in late Quaternary clay mineral assemblages presents mostly glacial-interglacial cyclicity, and they were interpreted chemical weathering closely related to contemporaneous climatic changes of source areas. It is quite debatable whether clay minerals can directly indicate the East Asian monsoon evolution. To answer this question, we investigated sediment cores collected in various locations in the South China Sea during the MARCO POLO cruise in 2005, MD05-2904 (2066 m water depth, abbreviated w.d.) and MD05-2905 (1198 m w.d.) in the north, MD05-2901 (1254 m w.d.) and MD05-2899 (2393 m w.d.) in the west, and MD05-2895 (1982 m w.d.) in the south. Our results show that provenance supply and current transport directly control the clay mineralogical compositions in core and surface sediments, with various expression forms in different locations. In the north, the clay mineral assemblage indicates a relationship between surface current transport (for smectite) under the significant influence of the Kuroshio intrusion and deep water transport (for illite and chlorite). In the west, the East Asian monsoons forced surface currents and different clay-composition provenances affect the glacial-interglacial cyclicity of clay mineral variations. In the south, land-sea distribution variations controlled by the sea level change determine the sources of clay minerals. Our new studies suggest that the late Quaternary clay minerals in the South China Sea do not bear contemporaneous paleoclimatic features, and their implication for proxies of the East Asian monsoon evolution is realized through both the provenance supply and current transport processes.

  18. Surficial clay mineral distribution on the southwestern continental margin of India: evidence of input from the Bay of Bengal

    Microsoft Academic Search

    Onkar S. Chauhan; A. R. Gujar

    1996-01-01

    Analyses of spatial distribution of clay minerals, sediment texture, and > 63 ?m fractions of the grab samples from the S W continental margin of India exhibit: (i) higher contents of illite and chlorite on the lower slope and (ii) a well-defined no-clay zone on the entire shelf. Kaolinite and smectite are also present in significant quantities on the slope

  19. Surficial clay mineral distribution on the southwestern continental margin of India: evidence of input from the Bay of Bengal

    Microsoft Academic Search

    Onkar S. Chauhan; A. R. Gujar

    1996-01-01

    Analyses of spatial distribution of clay minerals, sediment texture, and > 63 mum fractions of the grab samples from the S W continental margin of India exhibit: (i) higher contents of illite and chlorite on the lower slope and (ii) a well-defined no-clay zone on the entire shelf. Kaolinite and smectite are also present in significant quantities on the slope

  20. The formation of clay minerals in faulted granite of the Rhine rift system

    NASA Astrophysics Data System (ADS)

    Schleicher, A. M.; Warr, L. N.; Peacor, D. R.; van der Pluijm, B. A.

    2003-04-01

    Although the Rhine Graben is one of the best studied rift systems in the world, there is still relatively little known about the fluid-rock history of the faulted basement rocks, other than in the Soultz-Sous-Forets (HDR borehole). Effective modelling of the regional flow of fluids within the rift sequence and its underlying basement is dependent on knowledge concerning changes in permeability and porosity of basement faults, which can be empirically assessed by studying the alteration history of cataclasite samples. In this contribution we present the results of a combined X-ray diffraction and electron microscopy (SEM and HRTEM) study of low temperature altered cataclasites in the basement granite from two contrasting localities. 1) The Soultz-Sous-Forets borehole site (sampled below 1417 m), that is located in the western part of the rift basin, and 2) the E-W trending Schauenburg Fault, positioned along the eastern Rhine Graben shoulder. This latter structure marks a vertical contact between Permian rhyolite and Variscan granite and is positioned immediately adjacent to the N-S trending basin boundary fault. The alteration mineralogy of the cataclasites sampled from these localities reveal notable differences, which are considered to reflect variations in the faults burial-uplift and fluid history. The Soultz samples contain mostly anhedral and fibrous illite-muscovite (predominantly 2M polytype) and less chlorite as the main alteration products, which occur both as pore-filling minerals and as replacement products of feldspar (both plagioclase and K-feldspar) and biotite. In contrast, in the Schauenburg Fault 1Md illite/smectite polytypes dominate, along with significant quantities of kaolinite. These minerals are also formed by replacement of feldspars and as neocrystallized pore-filling material. Kaolinite is particularly abundant in the center of the fault, where several generations of well-developed pseudohexagonal stacks can be recognized, partially infilling pore-spaces of the fault rock. The origin of these clay growth events is discussed in terms of both Mesozoic and Tertiary thermal history and meteoric input along the margins of the Upper Rhine Graben region.

  1. Authigenic clay minerals in sandstones of the Delaware Mountain Group: Bell Canyon and Cherry Canyon Formations, Waha Field, West Texas

    E-print Network

    Walling, Suzette Denise

    1992-01-01

    AUTHIGENIC CLAY MINERALS IN SANDSTONES OF THE DELAWARE MOUNTAIN GROUP: BELL CANYON AND CHERRY CANYON FORMATIONS, WAHA FIELD, WEST TEXAS A Thesis by SUZETTE DENISE WALLING Submitted to the Office of Graduate Studies of Texas A&M University... in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1992 Major Subject: Geology AUTHIGENIC CLAY MINERALS IN SANDSTONES OF THE DELAWARE MOUNTAIN GROUP: BELL CANYON AND CHERRY CANYON FORMATIONS, WAHA FIELD, WEST TEXAS...

  2. Environmental perturbation in the southern Tethys across the Paleocene\\/Eocene boundary (Dababiya, Egypt): Foraminiferal and clay mineral records

    Microsoft Academic Search

    Sander R. Ernst; Elisa Guasti; Christian Dupuis; Robert P. Speijer

    2006-01-01

    Foraminiferal and clay mineral records were studied in the upper Paleocene to lower Eocene Dababiya section (Egypt). This section hosts the GSSP for the Paleocene\\/Eocene boundary and as such provides an expanded and relatively continuous record across the Paleocene\\/Eocene Thermal Maximum (PETM). Deposition of illite–smectite clay minerals is interpreted as a result of warm and arid conditions in the southern

  3. Investigating the Thermal Limit of Clay Minerals for Applications in Nuclear Waste Repository Design

    NASA Astrophysics Data System (ADS)

    Matteo, E. N.; Miller, A. W.; Kruichak, J.; Mills, M.; Tellez, H.; Wang, Y.

    2013-12-01

    Clay minerals are likely candidates to aid in nuclear waste isolation due to their low permeability, favorable swelling properties, and high cation sorption capacities. Establishing the thermal limit for clay minerals in a nuclear waste repository is a potentially important component of repository design, as flexibility of the heat load within the repository can have a major impact on the selection of repository design. For example, the thermal limit plays a critical role in the time that waste packages would need to cool before being transferred to the repository. Understanding the chemical and physical changes that occur in clay minerals at various temperatures above the current thermal limit (of 100 °C) can enable decision-makers with information critical to evaluating the potential trade-offs of increasing the thermal limit within the repository. Most critical is gaining understanding of how varying thermal conditions in the repository will impact radionuclide sorption and transport in clay materials either as engineered barriers or as disposal media. A variety of clays (illite, mixed layer illite/smectite, montmorillonite, and palygorskite) were heated for a range of temperatures between 100-500 °C. These samples were characterized by a variety of methods, including nitrogen adsorption, x-ray diffraction, thermogravimetric analysis, barium chloride exchange for cation exchange capacity (CEC), and iodide sorption. The nitrogen porosimetry shows that for all the clays, thermally-induced changes in BET surface area are dominated by collapse/creation of the microporosity, i.e. pore diameters < 17 angstroms. Changes in micro porosity (relative to no heat treatment) are most significant for heat treatments 300 °C and above. Alterations are also seen in the chemical properties (CEC, XRD, iodide sorption) of clays, and like pore size distribution changes, are most significant above 300 °C. Overall, the results imply that changes seen in pores size distribution correlate with cation exchange capacity and cation exchange processes. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's Nation Nuclear Security Administration under contract DE-AC04-94AL85000. SAND Number: 2013-6352A.

  4. [Effect of treatments of hydrogen peroxide and sodium dithionite-citrate-bicarbonate on clay minerals of red earth sediments].

    PubMed

    Li, Rong-Biao; Hong, Han-Lie; Yin, Ke; Wang, Chao-Wen; Gao, Wen-Peng; Han, Wen; Wu, Qing-Feng

    2013-04-01

    As classical procedures for pretreatment of soil sediments, hydrogen peroxide (H2O2) and sodium dithionite-citrate-bicarbonate (DCB) treatment methods are very important in removing the organic matter and iron oxides acting as cementing agents in the soils. However, both of these methods have less been focused on the effect on the clay minerals when separating. Here, we report the comparable methods between H2O2 and DCB to reveal their effect on clay minerals in red earth sediments using X-ray diffraction (XRD). The XRD results suggested that mineral particles can be totally decentralized by either H2O2 or DCB method in the soils and high purity clay minerals can be obtained by separating quartz and other impurities from clay minerals effectively. However, the XRD data were distorted by the DCB treatment owning to the cation exchange between Na+ and interlayer cation. On the contrary, the authentic data can be obtained by H2O2 treatment. Therefore, the H2O2 treatment seems to be a more appropriate method to obtain authentic information of clay mineralogy when separating of clay minerals from red earth sediments. PMID:23841441

  5. DE-FG02-06ER15364: Final Technical Report Nanoscale Reactivity of Clays, Clay Analogues (Micas), and Clay Minerals

    SciTech Connect

    Nagy, Kathryn L.

    2008-07-03

    The project objectives were to determine the nanoscale to molecular scale structure of the interface between muscovite mica and aqueous solutions containing various sorbates and to explore systematics that control the incorporation of inorganic and organic chemical components during aging of nanoparticles of iron-oxides and aluminosilicate clays. The basal surface of phyllosilicates is a primary sorbent of environmental contaminants, natural organic matter, and nutrients. Micas are also superb atomically-flat substrates used in materials science and surface physics applications. We applied X-ray scattering techniques using high brilliance synchrotron radiation to investigate molecular-scale details of mica’s interface structure in solutions containing common and toxic cations, anions, and natural organic molecules. Nanoparticles are ubiquitous in the environment and have a high capacity for sorbing contaminants through the combined effects of their high surface areas and pH-dependent surface charge. Aging of nanoparticles from metastable to stable phases can be inhibited by sorption of nonstructural components, but exact mechanisms are unknown. We synthesized Fe-oxides and aluminosilicate clay minerals from aqueous solutions in the presence of selected anions, and organic molecules, and quantified the uptake of these additives during aging and some implications for nanoparticle formation.

  6. Effect of organic matter properties, clay mineral type and thermal maturity on gas adsorption in organic-rich shale systems

    USGS Publications Warehouse

    Zhang, Tongwei; Ellis, Geoffrey S.; Ruppel, Stephen C.; Milliken, Kitty; Lewan, Mike; Sun, Xun

    2013-01-01

    A series of CH4 adsorption experiments on natural organic-rich shales, isolated kerogen, clay-rich rocks, and artificially matured Woodford Shale samples were conducted under dry conditions. Our results indicate that physisorption is a dominant process for CH4 sorption, both on organic-rich shales and clay minerals. The Brunauer–Emmett–Teller (BET) surface area of the investigated samples is linearly correlated with the CH4 sorption capacity in both organic-rich shales and clay-rich rocks. The presence of organic matter is a primary control on gas adsorption in shale-gas systems, and the gas-sorption capacity is determined by total organic carbon (TOC) content, organic-matter type, and thermal maturity. A large number of nanopores, in the 2–50 nm size range, were created during organic-matter thermal decomposition, and they significantly contributed to the surface area. Consequently, methane-sorption capacity increases with increasing thermal maturity due to the presence of nanopores produced during organic-matter decomposition. Furthermore, CH4 sorption on clay minerals is mainly controlled by the type of clay mineral present. In terms of relative CH4 sorption capacity: montmorillonite ? illite – smectite mixed layer > kaolinite > chlorite > illite. The effect of rock properties (organic matter content, type, maturity, and clay minerals) on CH4 adsorption can be quantified with the heat of adsorption and the standard entropy, which are determined from adsorption isotherms at different temperatures. For clay-mineral rich rocks, the heat of adsorption (q) ranges from 9.4 to 16.6 kJ/mol. These values are considerably smaller than those for CH4 adsorption on kerogen (21.9–28 kJ/mol) and organic-rich shales (15.1–18.4 kJ/mol). The standard entropy (?s°) ranges from -64.8 to -79.5 J/mol/K for clay minerals, -68.1 to -111.3 J/mol/K for kerogen, and -76.0 to -84.6 J/mol/K for organic-rich shales. The affinity of CH4 molecules for sorption on organic matter is stronger than for most common clay minerals. Thus, it is expected that CH4 molecules may preferentially occupy surface sites on organic matter. However, active sites on clay mineral surfaces are easily blocked by water. As a consequence, organic-rich shales possess a larger CH4-sorption capacity than clay-rich rocks lacking organic matter. The thermodynamic parameters obtained in this study can be incorporated into model predictions of the maximum Langmuir pressure and CH4- sorption capacity of shales under reservoir temperature and pressure conditions.

  7. Hydrogen and oxygen isotope exchange reactions between clay minerals and water

    USGS Publications Warehouse

    O'Neil, J.R.; Kharaka, Y.K.

    1976-01-01

    The extent of hydrogen and oxygen isotope exchange between clay minerals and water has been measured in the temperature range 100-350?? for bomb runs of up to almost 2 years. Hydrogen isotope exchange between water and the clays was demonstrable at 100??. Exchange rates were 3-5 times greater for montmorillonite than for kaolinite or illite and this is attributed to the presence of interlayer water in the montmorillonite structure. Negligible oxygen isotope exchange occurred at these low temperatures. The great disparity in D and O18 exchange rates observed in every experiment demonstrates that hydrogen isotope exchange occurred by a mechanism of proton exchange independent of the slower process of O18 exchange. At 350?? kaolinite reacted to form pyrophyllite and diaspore. This was accompanied by essentially complete D exchange but minor O18 exchange and implies that intact structural units in the pyrophyllite were inherited from the kaolinite precursor. ?? 1976.

  8. Clays, specialty

    USGS Publications Warehouse

    Virta, R.L.

    1998-01-01

    Part of a special section on the state of industrial minerals in 1997. The state of the specialty clay industry worldwide for 1997 is discussed. The specialty clays mined in the U.S. are ball clay, fuller's earth, bentonite, fire clay, and kaolin. Sales of specialty clays in the U.S. were around 17 Mt in 1997. Approximately 53 kt of specialty clays were imported.

  9. Atomic-level studies of the depletion in reactive sites during clay mineral dissolution

    SciTech Connect

    Sanders, Rebecca L.; Washton, Nancy M.; Mueller, Karl T.

    2012-09-01

    Environmental weathering is typically viewed as a macroscopic phenomenon that is based on a number of competing atomic- or molecular-level processes. One important process is the release of metal or metalloid elements into solution at the water-rock interface. To both explain and predict environmental weathering, the atomic-level “reactive sites” on the surfaces of minerals must be characterized and quantified. Whether these sites are atomic in nature, represented by a chemical bond, or comprise a more complex assemblage of covalently or ionically linked atoms or molecules, the kinetic rate of atomic release (dissolution) depends on the available reactive surface. For one important class of materials, clay minerals, their reactive surface areas are a challenge to quantify as it is well recognized that there are two distinct types of surfaces: edge sites and basal planes1-3. Clay dissolution rates continuously decrease over time as reactive edge sites are preferentially depleted4. Changes in reactive surface area and the difficulties in quantifying this elusive variable have often been cited as one key reason for the complexity in developing accurate rate equations3,5,6. In this work, we demonstrate a solid-state nuclear magnetic resonance (SSNMR) method for counting the number of reactive surface sites on a defined quantity of a clay mineral. Using this SSNMR proxy7-9, changes in reactive surface area were monitored for a series of batch dissolution experiments of low-defect kaolinite KGa-1b at 21 ºC and pH 3 over the course of 80 days. While no changes (within error) were observed for specific surface area (as determined from BET gas isotherm data), the SSNMR proxy revealed decreases in the number of reactive surface sites per gram of kaolinite as a function of dissolution time. This observation can be tied to a concomitant decrease in the rates of release of Si and Al into solution. These results further highlight the need to account for changes in reactive surface area when developing and using dissolution rate models for clay minerals and other heterogeneous materials in the environment.

  10. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2001-01-01

    Part of the 2000 annual review of the industrial minerals sector. A general overview of the ball clay industry is provided. In 2000, sales of ball clay reached record levels, with sanitary ware and tile applications accounting for the largest sales. Ball clay production, consumption, prices, foreign trade, and industry news are summarized. The outlook for the ball clay industry is also outlined.

  11. Mineral Surface Control of Organic Carbon Burial: Secular Rise of Clay Mineral Deposition in the Precambrian and the Rise of Oxygen

    NASA Astrophysics Data System (ADS)

    Kennedy, M. J.; Droser, M. L.; Mayer, L.; Pevear, D.

    2004-12-01

    Accumulation of oxygen in the earth's atmosphere requires burial of organic matter in marine sediments. Today, the major mode of organic carbon burial is in association with detrital pedogenic clay minerals which serve to protect organic matter against biological oxidation during burial in marine sediments. The bulk of detrital clays that are ultimately deposited in marine sediments are formed in biologically active soils that require plant processes to retain water, concentrate weathering produced solutes, stablize soils, and provide an adsorptive media. At some point in Earth history before the colonization of land surfaces by plants and the formation of biotic soils, clay mineral surface limitation may have severely reduced the preservation potential of organic carbon during burial. An important consequence of this would have also been a reduced flux of oxygen to the atmosphere because organic carbon and oxygen release are coupled. Multiple independent lines of evidence indicate a significant change in continental weathering and pedogenic clay mineral formation and establishment of the `clay factory' that coincides with colonization of land surfaces by primitive plant like organisms in the late Precambrian. The enhanced burial efficiency that would have accompanied the shift to the modern mode of detrital pedogenic clay hosted carbon burial would have driven an increase in oxygen levels toward present values. Evidence suggests that this rise in oxygen occurred just prior to the advent of the first complex animals in the Ediacaran.

  12. Clay minerals related to the hydrothermal activity of the Bouillante geothermal field (Guadeloupe)

    NASA Astrophysics Data System (ADS)

    Mas, A.; Guisseau, D.; Patrier Mas, P.; Beaufort, D.; Genter, A.; Sanjuan, B.; Girard, J. P.

    2006-11-01

    The geothermal field of Bouillante (Guadeloupe, FWI) is a high-enthalpy hydrothermal system emplaced in submarine volcanoclastic formations (hyaloclastites, scarce lava flows) and subaerial formations (andesitic lava flows, pyroclastites, lahars) which belong to the Lesser Antilles arc. Three directional wells were drilled in 2001 to optimize the productivity of the geothermal field up to 15 MWe and to investigate the vertical distribution of clay alteration from the surface area down to a depth of 1000 m where temperatures exceed 250 °C. Special attention has been paid to the "clay signature" of the fractured zones which channel the present geothermal fluids. Three successive zones, dominated, respectively by dioctahedral smectite, illite and chlorite were identified at increasing depths. Alteration petrography indicates that these mineralogical clay zones result from the spatial superimposition of at least two successive alteration stages. The first one, assimilated to a propylitic alteration stage, affected all parts of the system and consisted of crystallization of trioctahedral phyllosilicates (chlorite or corrensite), Ca-silicates (heulandite-clinoptilolite, prehnite, pumpelleyite, wairakite and epidote), quartz and minor calcite in replacement of most of the primary minerals of the intersected volcanic or volcanoclastic formations. The later stage of alteration is related to the circulation of the present geothermal fluids and is assimilated to argillic or phyllic alteration. It consists of a more or less intense argillization which results from the crystallization of aluminous dioctahedral clay phases (smectite, illite ± I-S mixed layers, and accessory kaolinite) associated with quartz, calcite, hematite or pyrite. The permeable zones which channel most of the present geothermal fluids are fracture controlled and do not contain specific clay parageneses. However the illite ± I-S mixed layers minerals differ from those of the surroundings by specific properties including both crystal structure and texture. These specific properties (decrease in the expandable component of the illitic material, increase of the illite crystallinity) can be controlled by the nucleation/growth rates operating in zones of active flow regime. Being mainly a product of the earlier propylitic alteration stage, chlorites are much less informative on the fracture controlled permeable levels. However, the compositional variations of chlorites recorded within the shallower fractured zone suggest a significant change in fO 2 conditions related to early circulation of fluids along the major near west striking normal faults (Plateau fault).

  13. Effects of heavy metals on the electrokinetic properties of bacteria, yeast, and clay minerals

    SciTech Connect

    Collins, Y.E.

    1987-01-01

    The electrokinetic patterns of four bacteria (Bacillus subtilis, Bacillus megaterium, Pseudomonas aeruginosa, Agrobacterium radiobacter), two yeasts (Saccharomyces cerevisiae, Canida albicans), and two clay minerals (montmorillonite, kaolinite) in the presence of the chloride salts of heavy metals (Cd, Cr, Cu, Hg, Ni, Pb, Zn) and of Na and Mg were determined by microelectrophoresis. The cells and clays were net negatively charged at pH values above their isoelectric point (pI) in solutions of Na, Mg, Hg, and Pb with an ionic strength (..mu..) of 3 x 10/sup -4/. However, at pH values above pH 5.0, the charge of some bacteria, S. cerevisiae, and kaolinite changed to a net positive charge (charge reversal) in the presence of Cd, Cr, Cu, Ni, and Zn. The charge of the bacteria and S. cerevisiae also reversed in solution of Ni and Cu with a ..mu.. > 3 x 10/sup -4/, whereas there was no reversal in solutions with a ..mu.. < 3 x 10/sup -4/. The clays became net positively charged when the ..mu.. of Cu was > 3 x 10/sup -4/ and that of Ni was > 1.5 x 10/sup -4/. The charge of the cells and clays also reversed in solutions containing both Mg and Ni or both Cu and Ni (except montmorillonite) but not in solutions containing both Mg and Cu (except kaolinite) (..mu.. = 3 x 10/sup -4/). The pI of the cells in the presence of some heavy metals, especially Ni and Cr, was at higher pH values than in the presence of Na and Mg.

  14. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2007-01-01

    The article offers information on ball clay. Among the companies that mine ball clay in the U.S. are H.C. Spinks Clay, Kentucky-Tennessee Clay and Old Hickory Clay. In 2006, an estimated 1.2 million tons of the mineral was sold or used domestically and exported. Forty-percent of the total sales is accounted for ceramic floor and wall tile followed by sanitaryware and miscellaneous ceramics. Its average value was $ 45 per ton in 2006.

  15. Clay fractions from a soil chronosequence after glacier retreat reveal the initial evolution of organo-mineral associations

    NASA Astrophysics Data System (ADS)

    Dümig, Alexander; Häusler, Werner; Steffens, Markus; Kögel-Knabner, Ingrid

    2012-05-01

    Interactions between organic and mineral constituents prolong the residence time of organic matter in soils. However, the structural organization and mechanisms of organic coverage on mineral surfaces as well as their development with time are still unclear. We used clay fractions from a soil chronosequence (15, 75 and 120 years) in the foreland of the retreating Damma glacier (Switzerland) and from mature soils outside the proglacial area (>700 and <3000 years) to elucidate the evolution of organo-mineral associations during initial soil formation. The chemical composition of the clay-bound organic matter (OM) was assessed by solid-state 13C NMR spectroscopy while the quantities of amino acids and neutral sugar monomers were determined after acid hydrolysis. The mineral phase was characterized by X-ray diffraction, oxalate extraction, specific surface area by N2 adsorption (BET approach), and cation exchange capacity at pH 7 (CECpH7). The last two methods were applied before and after H2O2 treatment. We found pronounced shifts in quantity and quality of OM during aging of the clay fractions, especially within the first one hundred years of soil formation. The strongly increasing organic carbon (OC) loading of clay-sized particles resulted in decreasing specific surface areas (SSA) of the mineral phases and increasing CECpH7. Thus, OC accumulation was faster than the supply of mineral surfaces and cation exchange capacity was mainly determined by the OC content. Clay-bound OC of the 15-year-old soils showed high proportions of carboxyl C and aromatic C. This may point to remnants of ancient OC which were inherited from the recently exposed glacial till. With increasing age (75 and 120 years), the relative proportions of carboxyl and aromatic C decreased. This was associated with increasing O-alkyl C proportions, whereas accumulation of alkyl C was mainly detected in clay fractions from the mature soils. These findings from solid-state 13C NMR spectroscopy are in line with the increasing amounts of microbial-derived carbohydrates with soil age. The large accumulation of proteins, which was comparable to those of carbohydrates, and the very low C/N ratios of H2O2-resistant OM indicated strong and preferential associations between proteinaceous compounds and mineral surfaces. In the acid soils, poorly crystalline Fe oxides were the main providers of mineral surface area and important for the stabilization of OM during aging of the clay fractions. This was indicated by (I) the strong correlations between oxalate soluble Fe and both, SSA of H2O2-treated clay fractions and OC content, and (II) the low formation of expandable clays due to small extents of mineral weathering. Our chronosequence approach provided new insights into the evolution of organo-mineral interactions in acid soils. The formation of organo-mineral associations started with the sorption of proteinaceous compounds and microbial-derived carbohydrates on mineral surfaces which were mainly provided by ferrihydrite. The sequential accumulation of different organic compounds and the large OC loadings point to multiple accretion of OM in distinct zones or layers during the initial evolution of clay fractions.

  16. CLAY MINERALOGY OF INSOLUBLE RESIDUES IN MARINE EVAPORITES.

    USGS Publications Warehouse

    Bodine, Marc W., Jr.

    1985-01-01

    Insoluble residues from three sequences of Paleozoic marine evaporites (Retsof salt bed in western New York, Salado Formation in south-eastern New Mexico, and Paradox Member of the Hermosa Formation in southeastern Utah) are rich in trioctahedral clays. Chlorite (clinochlore), corrensite (mixed-layer chlorite-trioctahedral smectite), talc, and illite (the only dioctahedral clay) are the dominant clay minerals; serpentine, discrete trioctahedral smectite (saponite), and interstratified talc-trioctahedral smectite are sporadically abundant. These clay-mineral assemblages differ chemically and mineralogically from those observed in most continental and normal marine rocks, which commonly contain kaolinite, dioctahedral smectite (beidellite-montmorillonite), illite, mixed-layer illite-dioctahedral smectite, and, in most cases, no more than minor quantities of trioctahedral clay minerals. The distinctive clay mineralogy in these evaporite sequences suggests a largely authigenic origin. These clay minerals are thought to have formed during deposition and early diagenesis through interaction between argillaceous detritus and Mg-rich marine evaporite brines.

  17. Neogene sandstone reservoirs of the East Slovakian basin: Zeolites and clay minerals from the alteration of volcanics

    SciTech Connect

    Reed, J.K.; Gipson, M. Jr. (Univ. of South Carolina, Columbia (United States))

    1991-03-01

    Petrographic analyses of core samples from wells in the East Slovakian basin indicate that alteration products of volcanic materials cause porosity loss in sandstone reservoirs. The reservoirs, which produce natural gas, are part of a shallow marine to continental basin fill with interbedded volcaniclastics, tuffs, and volcanites. Abnormally high heat-flow values have been recorded in the basin fill, which reaches up to 7 km in thickness. Both clay minerals and zeolites are found to restrict porosity. Kaolinite, smectite, illite, chlorite, and mixed-layer clay minerals are all identified in various combinations. Zeolites identified include phillipsite, erionite, clinoptilolite, and analcime. These minerals are related to the occurrence of volcanic rock fragments in the reservoir sand and interbedded volcanics, and they occur as diagenetic replacement minerals and cements. The effects of these minerals are compounded by the initial poor reservoir quality caused by immature sediments and calcite cement. Reservoir productivity would probably be increased if drilling and completion practices in the basin reflected the potential effects of the clay minerals and zeolites.

  18. The origin of the pozzolanic activity of calcined clay minerals: A comparison between kaolinite, illite and montmorillonite

    SciTech Connect

    Fernandez, Rodrigo, E-mail: fernandezrod@gmail.co [Laboratory of Construction Materials, IMX, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland); Martirena, Fernando [Centro de Investigacion y Desarrollo de Estructuras y Materiales (CIDEM), Universidad Central 'Marta Abreu' de Las Villas, 54830 Santa Clara (Cuba); Scrivener, Karen L. [Laboratory of Construction Materials, IMX, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland)

    2011-01-15

    This paper investigates the decomposition of three clayey structures (kaolinite, illite and montmorillonite) when thermally treated at 600 {sup o}C and 800 {sup o}C and the effect of this treatment on their pozzolanic activity in cementitious materials. Raw and calcined clay minerals were characterized by the XRF, XRD, {sup 27}Al NMR, DTG and BET techniques. Cement pastes and mortars were produced with a 30% substitution by calcined clay minerals. The pozzolanic activity and the degree of hydration of the clinker component were monitored on pastes using DTG and BSE-IA, respectively. Compressive strength and sorptivity properties were assessed on standard mortars. It was shown that kaolinite, due to the amount and location of OH groups in its structure, has a different decomposition process than illite or montmorillonite, which results in an important loss of crystallinity. This explains its enhanced pozzolanic activity compared to other calcined clay-cement blends.

  19. NMR spectroscopic investigations of surface and interlayer species on minerals, clays and other oxides

    SciTech Connect

    Kirkpatrick, R.J.; Yeongkyoo Kim [Univ. of Illinois, Urbana, IL (United States). Department of Geology; Weiss, C.A. [Army Engineer Waterways Experiment Station, Vicksburg, MS (United States). Structures Laboratory; Cygan, R.T. [Sandia National Laboratories, Albuquerque, NM (United States)

    1996-07-01

    The behavior of chemical species adsorbed on solid surfaces and exchanged into clay interlayers plays a significant role in controlling many natural and technologically important processes, including rheological behavior, catalysis, plant growth, transport in natural pore fluids and those near anthropogenic hazardous waste sites, and water-mineral interaction. Adsorption and exchange reactions have been the focus of intense study for many decades. Only more recently, however, have there been extensive spectroscopic studies of surface species. Among the spectroscopic methods useful for studying surface and exchanged species (e.g., infrared, X-ray photoelectron spectroscopy [XPS] and X-ray absorption spectroscopy [XAS]), nuclear magnetic resonance spectroscopy (NMR) has the considerable advantage of providing not only structural information via the chemical shift and quadrupole coupling constant but dynamical information in the Hz-mHz range via lineshape analysis and relaxation rate measurements. It is also possible to obtain data in the presence of a separate fluid phase, which is essential for many applications. This paper illustrates the range of applications of NMR methods to surface and exchanged species through review of recent work from our laboratory on Cs in clay interlayers and Cs, Na and phosphate adsorbed on oxide surfaces. The substrate materials used for these experiments and our long-term objectives are related to problems of geochemical interest, but the principals and techniques are of fundamental interest and applicable to a wide range of technological problems.

  20. Use of clay-mineral alteration patterns to define syntectonic permeability of joints (cleat) in Pennsylvania anthracite coal

    Microsoft Academic Search

    E. J. Daniels; S. Marshak; S. P. Altaner

    1996-01-01

    Joints (cleat) in Pennsylvania anthracite contain two distinct clay-mineral assemblages, both of which formed by alteration of preexisting kaolinite at peak metamorphic conditions during the Alleghanian orogeny. The first assemblage, NH4-illite or pyrophyllite ± quartz, formed by reaction of kaolinite with methane-rich fluids derived from within the coal. The second assemblage, sudoite ± tosudite ± rectorite ± berthierine, formed by

  1. Chemical and structural analysis of enhanced biochars: thermally treated mixtures of biochar, chicken litter, clay and minerals.

    PubMed

    Lin, Y; Munroe, P; Joseph, S; Ziolkowski, A; van Zwieten, L; Kimber, S; Rust, J

    2013-03-01

    In this study biochar mixtures comprising a Jarrah-based biochar, chicken litter (CL), clay and other minerals were thermally treated, via torrefaction, at moderate temperatures (180 and 220 °C). The objectives of this treatment were to reduce N losses from CL during processing and to determine the effect of both the type of added clay and the torrefaction temperature on the structural and chemical properties of the final product, termed as an enhanced biochar (EB). Detailed characterisation indicated that the EBs contained high concentrations of plant available nutrients. Both the nutrient content and plant availability were affected by torrefaction temperature. The higher temperature (220 °C) promoted the greater decomposition of organic matter in the CL and dissociated labile carbon from the Jarrah-based biochar, which produced a higher concentration of dissolved organic carbon (DOC). This DOC may assist to solubilise mineral P, and may also react with both clay and minerals to block active sites for P adsorption. This subsequently resulted in higher concentrations of plant available P. Nitrogen loss was minimised, with up to 73% of the initial total N contained in the feedstock remaining in the final EB. However, N availability was affected by both torrefaction temperature and the nature of the clay minerals added. PMID:23270707

  2. Isotope fractionation during Ca exchange on clay minerals in a marine environment

    NASA Astrophysics Data System (ADS)

    Ockert, C.; Gussone, N.; Kaufhold, S.; Teichert, B. M. A.

    2013-07-01

    In order to interpret marine porewater profiles it is mandatory to understand the behavior of calcium (Ca) and its isotopes during cation exchange in marine sediments. It has been proposed that the exchange of adsorbed Ca2+ for ammonium, which is a product of organic matter decomposition, results in the releases of light Ca from clay minerals into the porewater (Teichert et al., 2009). In order to investigate the effect of ammonium on Ca isotope fractionation, experiments with clay mineral separates (illites, montmorillonite, kaolinite) and natural marine sediments from the North Atlantic (Integrated Ocean Drilling Project Site U1306A) in artificial seawater were carried out at different temperatures (4, 14, 21 °C) and ammonium concentrations (100, 140, 180 mM). The results of the adsorption experiments, carried out in artificial seawater, show that during adsorption of Ca2+ the light Ca isotopes are favored over the heavier Ca isotopes. This effect is most prominent for the illite samples (1000ln? = -0.82 to -1.15) and kaolinite sample (1000ln? = -1.23 to -2.76), whereas montmorillonite and the natural marine sediments show smaller degrees of fractionation from the fluid in the range of -0.46 to +0.06‰. Determination of the desorbed Ca2+ is based on the adsorbed Ca2+ left on the exchanger and reveals that the desorbed Ca2+ has a significantly different isotopic signature from the surrounding fluid. In general, the degree of Ca isotope fractionation is dependent on the ammonium concentration, and does not show significant influence of temperature. Modeling the Ca2+ desorption induced by ammonium adsorption demonstrates, that according to the prevailing mineralogy and porewater:sediment ratio, desorbed Ca2+ has the potential to shift the porewater isotopy by up to -2.5‰ and needs to be considered when interpreting Ca isotope porewater profiles.

  3. Changes of clay mineral assemblages in Lake Hovsgol (Mongolia) in the course of their transportation and sedimentation

    NASA Astrophysics Data System (ADS)

    Zhdanova, A.; Solotchina, E.; Krivonogov, S.

    2009-04-01

    As known, clay minerals of lake sediments sensitively indicate climatic and environmental changes. Composition of clay mineral assemblages depends on petrography and weathering pattern of parental rocks in lake catchments. Lake Hovsgol, the second large basin in the Baikal Rift Zone, differs from the first one by extremely small drainage area: its ratio to the lake surface is 1.8 (compare with 17 of Lake Baikal). This peculiarity of lake Hovsgol defines the amount of clay minerals deposited in bottom sediments and the value of their transformation in the course of transportation We studied a number of short sediment cores (up to 1.75 m long) obtained from different parts of the lake in the framework of the Hovsgol Drilling Project, 2001-2007. Regularities of modern clay minerals transportation were studied in 80 samples from river mouths and piedmont slopes around the lake. Their mineral composition was determined by X-ray powder diffraction and IR-spectroscopy. For X-ray, we prepared the oriented mounts by transferring the suspension of bulk sample in distilled water onto a glass slide. Slides, dried at room temperature, then were solvated for about 24 hours with ethylene-glycol vapor in an evacuated desiccator. Measurements were conducted on an automated powder diffractometer with CuK? radiation, graphite monochromator. The comparative analysis of clay minerals and their crystallochemical parameters were performed by the original method of modeling X-ray diffraction profiles, based on the calculation of the interference function of the one-dimensional disordered crystals with finite thickness and using a specially developed optimization procedure. Quantitative estimations of the composition of minerals such as quartz, plagioclase, carbonate were made by IR-spectroscopy. Samples were prepared using the KBr pellet method. It was established that the mineral association in bottom sediments includes illite, smectite, chlorite, chlorite-smectite, muscovite, kaolinite and quartz, feldspar, amphibole, carbonates. Except these minerals which were also indentified in the samples collected in drainage basin partly weathered biotite was observed. The total amounts of minerals in some drainage basin samples are higher than in bottom sediment. The quantitative distribution of clay mineral on the bottom depends on the type of parental rocks and their location in drainage basin. For instance, on the eastern shore of the lake where granites and basalt prevail feldspar weathers to smectite and we can observe that in the cores located near this shore more smectite is found than in the cores near the western side where carbonate rocks are widespread. The studying of drainage basin rocks and products of their weathering allows us to understand the clay mineral formation and their alteration during the process of transportation and deposition in lake bottom sediments. The comparison of clay minerals from watershed with these of bottom sediments helps us to evaluate the role of authegenic and diagenetic formation. The work was supported by RFBR, project 08-05-00680.

  4. Is the clogging process in Maqarin natural analogue controlled by accessory clay minerals? A reactive transport study with new data.

    NASA Astrophysics Data System (ADS)

    Shao, H.; Kosakowski, G.; Berner, U.; Kulik, D.; Mäder, U.; Kolditz, O.

    2012-04-01

    The safety of nuclear waste repositories is based on the functionality of multiple natural and engineered barriers for very long time. The barrier system typically combines geochemically different materials that might interact with each other. One example is the long term alteration of sedimentary host rocks by the interaction with high pH pore water from cement materials used for tunnel support, seals and as backfill material. Within this context the Maqarin site in Jordan was investigated since more than 20 years as a natural analogue for rock alterations and pore clogging due to ingress of high pH solutions. In this work we examine the geochemical evolution of Maqarin marl rock in contact with a fracture through which a hyper-alkaline groundwater is circulating. The new reactive transport calculations were performed with the code OpenGeoSys-GEMS and utilize a state-of-the-art geochemical model for cement-clay interactions. The simulations reveal that the precipitation of ettringite, and to a smaller extent the precipitation of calcium-silicate-hydrate (CSH), is responsible for pore clogging in the rock matrix. Clogging of the pore space effectively seals the rock matrix on a centimeter scale after some hundreds of years and suppresses mass transfer of solutes from the fracture into the adjacent rock. In our Maqarin marl rock model typical clay minerals like kaolinite and illite are present in accessory mineral quantities only. A sensitivity analysis reveals that in this setup clay minerals are the main source for Al, necessary for the formation of ettringite-type solid solutions. It is thus the clay mineral content and the dissolution reactions that to a large degree control the spatial and temporal precipitation of ettringites and the associated pore clogging. Recently collected mineralogy and porosity data will be used to re-calibrate the model and to verify our improved findings that overall Maqarin system is controlled by accessory clay minerals.

  5. Clay Minerals of Suspended Matter and Surficial Sediments of Khor Al-Zubair Estuary, NW Arabian Gulf

    NASA Astrophysics Data System (ADS)

    Al-Mussawy, Sabah N.; Basi, Muzahim A.

    1993-02-01

    Distribution of clay minerals in the suspended matter and surficial sediments of 36 samples collected from Khor Al-Zubair estuary revealed the presence of montimorillonite, kaolinite, chlorite, illite and palygorskite in wide variations. These variations are interpreted to be due to: different source areas of these minerals, the complex hydrodynamic conditions in the Khor and to flocculation. No regular distribution of clay minerals (except for montimorillonite) was found in the water samples. In the sediments samples montimorillonite and palygorskite showed a trend of increasing values toward the Arabian Gulf, which interpreted to be brought by Shatt Al-Arab River and/or formed diagenetically. Kaolinite and chlorite increased landward due to eolian effect. Illite values showed an increment near Shatt Al-Basrah Canal caused by the sediments brought by the Euphrates River from Hor Al-Hammar Lake.

  6. Distribution of clay minerals in surface sediments of the western Gulf of Thailand: Sources and transport patterns

    NASA Astrophysics Data System (ADS)

    Shi, Xuefa; Liu, Shengfa; Fang, Xisheng; Qiao, Shuqing; Khokiattiwong, Somkiat; Kornkanitnan, Narumol

    2015-06-01

    A high density sampling program during two joint China-Thailand scientific cruises in 2011-2012 included collection of 152 gravity box cores in the Gulf of Thailand (GoT). Samples from the top 5 cm of each core were analyzed by X-ray diffraction for clay mineral content. Several systemic analytical approaches were applied to examine the distribution pattern and the constraint factors of clay minerals in the surface sediments of the western GoT. The clay minerals mainly comprise illite, kaolinite, chlorite and smectite, having the average weight percent distributions of 50%, 34%, 14% and 2%, respectively. Based on the spatial distribution characteristics and statistical results, the study area can be classified into three provinces. Province I contains high concentrations of smectite, and covers the northern GoT, sediments in this province are mainly from rivers discharging into the upper GoT, especially the Chao Phraya and Mae Klong Rivers. Sediments in Province II are characterized by higher values of illite, located in the central GoT, where fine sediments are contributed by the Mekong River and from the South China Sea. Province ?, in the coastal regions of southwestern GoT close to Malaysia, exhibits a clay mineral assemblage with complex distribution patterns, and may contain terrestrial materials from the Mae Klong River as well as re-suspended sediments. Results of integrative analysis also demonstrate that the hydrodynamic environment in the study area, especially the seasonal various circumfluence and eddies, play an important role in the spatial distribution and dispersal of clay fraction in sediments.

  7. Chemical and Structural Changes in Aluminosilicate Clay Minerals Caused by Exposure to Acid and Implications for Ice Nucleation

    NASA Astrophysics Data System (ADS)

    Sihvonen, S.; Lyktey, N. A.; Freedman, M. A.

    2013-12-01

    Several recent studies have shown that sulfuric acid lowers the activity of clay minerals toward ice nucleation. In order to understand the origins of the reported decrease in ice nucleation activity, we have investigated the chemical and structural changes that occur to swelling and non-swelling clay minerals upon processing with sulfuric and nitric acid. Using X-ray diffraction (XRD), we have observed that kaolinite and montmorillonite reactions with sulfuric acid result in the formation of hydrated aluminum sulfate. In addition, the montmorillonite lattice changes during the reaction. Nitric acid has no effect on either type of mineral. Structural changes to the minerals were additionally visualized using transmission electron microscopy (TEM). These images suggest that sulfuric acid attacks the edges of kaolinite. We have also performed inductively coupled plasma - atomic emission spectroscopy (ICP-AES) to investigate the leaching of cations from these minerals. We will discuss the implications of our results for heterogeneous ice nucleation, and will show results from ice nucleation experiments with our processed minerals.

  8. Heavy metals alter the electrokinetic properties of bacteria, yeasts, and clay minerals

    SciTech Connect

    Collins, Y.E.; Stotzky, G. (New York Univ., NY (United States))

    1992-05-01

    The electrokinetic patterns of four bacterial species (Bacillus subtilis, Bacillus megaterium, Pseudomonas aeruginosa, and Agrobacterium radiobacter), two yeasts (Saccharomyces cerevisiae and Candida albicans), and two clay minerals (montmorillonite and kaolinite) in the presence of the chloride salts of the heavy metals, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, and of Na and Mg were determined by microelectrophoresis. The cells and kaolinite were net negatively charged at pH values above their isoelectric points (pI) in the presence of Na, Mg, Hg, and Pb at an ionic strength ([mu]) of 3 [times] 10[sup [minus]4]; montmorillonite has no pI and was net negatively charged at all pH values in the presence of these metals. However, the charge of some bacteria, S. cerevisiae, and kaolinite changed to a net positive charge (charge reversal) in the presence of Cd, Cr, Cu, Ni, and Zn at pH values above 5.0 and then at higher pH values, again became negative. The charge of the bacteria and S. cerevisiae also reversed in solutions of Cu and Ni with a [mu] of >3 [times] 10[sup [minus]4], whereas there was no reversal in solutions with a [mu] of <3 [times] 10[sup [minus]4]. The clays became net positively charged when the [mu] of Cu was >3 [times] 10[sup [minus]4] and that of Ni was >1.5 [times] 10[sup [minus]4]. The charge of the cells and clays also reversed in solutions containing both Mg and Ni or both Cu and Ni (except montmorillonite) but not in solutions containing both Mg and Cu (except kaolinite). The pIs of the cells in the presence of the heavy metals were at either higher or lower pH values than in the presence of Na and Mg. Exposure of the cells to the various metals at pH values from 2 to 9 for the short times (ca. 10 min) required to measured the electrophoretic mobility did not affect their viability.

  9. Clays, common

    USGS Publications Warehouse

    Virta, R.L.

    1998-01-01

    Part of a special section on the state of industrial minerals in 1997. The state of the common clay industry worldwide for 1997 is discussed. Sales of common clay in the U.S. increased from 26.2 Mt in 1996 to an estimated 26.5 Mt in 1997. The amount of common clay and shale used to produce structural clay products in 1997 was estimated at 13.8 Mt.

  10. Tectonic?palaeoenvironmental forcing of clay-mineral assemblages in nonmarine settings: the Oligocene?Miocene As Pontes Basin (Spain)

    NASA Astrophysics Data System (ADS)

    Sáez, A.; Inglès, M.; Cabrera, L.; de las Heras, A.

    2003-07-01

    Two small, alluvial-lacustrine subbasins developed during the early restraining overstep stages of the Oligocene-Miocene As Pontes strike-slip Basin (NW Spain). Later, the basin evolved into a restraining bend stage and an alluvial-swamp-dominated depositional framework developed. The palaeobiological record demonstrates that the Oligocene-Miocene palaeoclimate in NW Spain was subtropical, warm and humid to subhumid. The metamorphic and igneous basin catchment yielded clay assemblages made up by kaolinite, illite and Al-smectite. Illite occurred as an original mineral in the source rock area, whereas kaolinite and Al-smectite resulted mainly from weathering of feldspar and clinochlore, respectively. This detrital primary clay assemblage remained preserved in the colluvial, alluvial fan and shallow lacustrine facies, whose early diagenesis was influenced by diluted, poorly evolved pore waters with neutral to slightly alkaline pH. The original clay assemblage was mildly to strongly transformed under early diagenetic conditions in the lacustrine and swampy environments where significant hydrochemical and Eh-pH changes took place. A fibrous magnesium-rich clay mineral-dominated assemblage (palygorskite and sepiolite) formed in shallow, saline lakes and palustrine zones under the influence of magnesium-rich, alkaline waters. Moreover, kaolinite-enriched assemblages formed in deep lacustrine, swamp and swamp-related alluvial zones under the influence of slightly to highly acidic pore waters. Pore water acidic conditions, characterising environments with organic matter accumulation, led to early diagenetic transformation of Al-smectite into kaolinite. This process was relatively limited in some environments such as organic matter-rich bottoms in meromictic lacustrine zones, whereas it was pervasive in peat-forming swamp zones. The stratigraphic relationships between the diverse clay mineral assemblages in the As Pontes Basin fill demonstrate the coeval development of rather diverse clay compositions. This clearly reflects the influence on clay assemblages of palaeoenvironmental changes forced by the morphological and tectonic evolution of the catchment-basin system. The interplay between climate and tectonic processes in the source areas did not result in major variations of the clay minerals fed into the basin. Conversely, this tectonic-sedimentation interplay influenced the evolution of the drainage and the water balance in the depositional zones, causing a complex environmental-hydrochemical evolution to occur. As a consequence, drastic early diagenetic changes affected the original clay mineral assemblages and resulted in a variety of early diagenetic assemblages. The As Pontes case study emphasises the major influence of palaeogeographical and tectonosedimentary evolution on the clay mineral record in nonmarine depositional systems. The depositional record in As Pontes Basin demonstrates that morphological and tectonically forced environmental and hydrochemical changes can result in variations similar to those forced by low-order climatic changes and that, in some cases, the role of climate can be negligible.

  11. Areal distribution of clay minerals and their relationship to physical properties, Gulf of Mexico

    E-print Network

    Hottman, William Edward

    1975-01-01

    Objectives. REVIEW OF PERTINENT LITERATURE Clay Mineralogy Physical Properties PROCEDURES 4 6 Sampling. Preparation of Clay Samples for X-Ray Diffraction Analysis. X-Ray Diffraction Transmission Electron Microscopy Procedures CLAY MINERALOGY. 8... Procedures Transmission electron micrographs were taken from Four cores in a northeast-southwest line across the Gulf of Mexico. in order to com- pare the morphology of the clays with the X-ray diffraction data, a small amount of sample was scraped from...

  12. Evaluation of the medicinal use of clay minerals as antibacterial agents

    Microsoft Academic Search

    Lynda B. Williams; Shelley E. Haydel

    2010-01-01

    Natural clays have been used to heal skin infections since the earliest recorded history. Recently, our attention was drawn to a clinical use of French green clay (rich in Fe?smectite) for healing Buruli ulcer, a necrotizing fasciitis (‘flesh-eating’ infection) caused by Mycobacterium ulcerans. These clays and others like them are interesting as they may reveal an antibacterial mechanism that could

  13. Numerical Simulation of Injectivity Effects of Mineral Scaling and Clay Swelling in a Fractured Geothermal Reservoir

    SciTech Connect

    Xu, Tianfu; Pruess, Karsten

    2004-05-10

    A major concern in the development of hot dry rock (HDR) and hot fractured rock (HFR) reservoirs is achieving and maintaining adequate injectivity, while avoiding the development of preferential short-circuiting flow paths such as those caused by thermally-induced stress cracking. Past analyses of HDR and HFR reservoirs have tended to focus primarily on the coupling between hydrology (flow), heat transfer, and rock mechanics. Recent studies suggest that rock-fluid interactions and associated mineral dissolution and precipitation effects could have a major impact on the long-term performance of HFR reservoirs. The present paper uses recent European studies as a starting point to explore chemically-induced effects of fluid circulation in HFR systems. We examine ways in which the chemical composition of reinjected waters can be modified to improve reservoir performance by maintaining or even enhancing injectivity. Chemical manipulations considered here include pH modification and dilution with fresh water. We performed coupled thermo-hydrologic-chemical simulations in which the fractured medium was represented by a one-dimensional MINC model (multiple interacting continua), using the non-isothermal multi-phase reactive geochemical transport code TOUGHREACT. Results indicate that modifying the injection water chemistry can enhance mineral dissolution and reduce clay swelling. Chemical interactions between rocks and fluids will change a HFR reservoir over time, with some changes favorable and others not. A detailed, quantitative understanding of processes and mechanisms can suggest chemical methods for reservoir management, which may be employed to improve the performance of the geothermal system.

  14. Use of clay-mineral alteration patterns to define syntectonic permeability of joints (cleat) in Pennsylvania anthracite coal

    NASA Astrophysics Data System (ADS)

    Daniels, E. J.; Marshak, S.; Altaner, S. P.

    1996-10-01

    Joints (cleat) in Pennsylvania anthracite contain two distinct clay-mineral assemblages, both of which formed by alteration of preexisting kaolinite at peak metamorphic conditions during the Alleghanian orogeny. The first assemblage, NH 4-illite or pyrophyllite ± quartz, formed by reaction of kaolinite with methane-rich fluids derived from within the coal. The second assemblage, sudoite ± tosudite ± rectorite ± berthierine, formed by the reaction of kaolinite with ferromagnesian-bearing hydrothermal fluids which must have come from outside the coal. In an earlier paper, we suggested that the first assemblage indicated clay diagenesis in low-permeability environments, and that the second assemblage indicated clay diagenesis in high-permeability environments. If this premise is correct, then the distribution of clay-mineral alteration assemblages serves to define syntectonic permeability variations in coal cleat. The first assemblage dominates in the coal matrix itself, in isolated cleat, in cleat that parallel the regional trend of Alleghanian folds, and in the mirror portions of cleat oriented perpendicular to the fold trends, suggesting that these regions are low-permeability environments. The second assemblage dominates in the hackle fringe of interconnected cleat that trend perpendicular to the strike of the Appalachian orogen, suggesting that these regions are high-permeability environments. Our results emphasize that syntectonic cleat permeability is a function of cleat orientation, macroscopic cleat interconnectivity and orientation, as well as microscopic cleat-surface morphology.

  15. Clay Mineral Associations in Triassic–Lower Cretaceous Rocks of the Dal'negorsk Key Section, Southern Sikhote Alin

    Microsoft Academic Search

    M. I. Tuchkova; N. Yu. Bragin; K. A. Krylov

    2004-01-01

    Investigation of the Triassic–Lower Cretaceous rocks of the Dal'negorsk key section (southern Sikhote Alin) revealed the following successive associations of authigenic clay minerals: (1) sericite–chlorite (Lower Triassic); (2) mica–chlorite (Anisian–Norian); (3) chlorite–mica (Rhaetian–Lower Jurassic); and (4) smectite–chlorite–mica (Upper Jurassic–Lower Cretaceous). These four associations reflect the primary composition of terrigenous admixture in the siliceous sediments and, hence, serve as important indicators

  16. Use of fast field cycling NMR for the evaluation of the interactions between natural organic matter and clay minerals

    NASA Astrophysics Data System (ADS)

    Conte, Pellegrino; Abbate, Cristina; Baglieri, Andrea; Alonzo, Giuseppe; de Pasquale, Claudio; Nègre, Michéle; Gennari, Mara

    2010-05-01

    Natural organic matter (NOM) is a very important soil and water constituent due to its role in binding organic and inorganic pollutants, thereby affecting their fate in the environmental compartments. Prediction of NOM physical-chemical properties can be efficaciously achieved by studying its structure and three dimensional conformation. Many techniques can be used to this aim. Among others, fast field cycling nuclear magnetic resonance relaxometry (FFC-NMR) appears very suitable due to its ability in monitoring NOM conformational behaviour at very low magnetic fields. The present study aims to the evaluation by FFC-NMR relaxometry of the interactions between a dissolved humic material and two clay minerals. In particular, FFC-NMR showed that either kaolinite or montmorrillonite adsorb part of the organic material. Absorption degree is proportional to the surface area of the two clay minerals, while the adsorbed fraction resulted the most polar part of dissolved organic matter due to the disappearing of the components relaxing at the longest longitudinal relaxation times. This study showed that FFC-NMR is more sensitive than high field NMR spectroscopy in monitoring the conformational changes occurring during the interactions between natural organic matter and clay minerals. Acknowledgements This work was partially funded by Ce.R.T.A. s.c.r.l. (Centri Regionali per le Tecnologie Alimentari; http://www.certa.it/default.asp).

  17. Pathways of clay mineral transport in the coastal zone of the Brazilian continental shelf from Ceará to the mouth of the Amazon River

    Microsoft Academic Search

    J. O. de Morais; M. Tintelnot; G. Irion; L. Souza Pinheiro

    2006-01-01

    The transport pathways of fine sediments (fraction <2 ?m) along the Brazilian continental shelf from Ceará to the Amazon River\\u000a mouth were studied by means of clay mineral analyses. On the continental shelf southeast of the Amazon mouth, fluctuations\\u000a in clay mineral compositions reflect simple mixing between the suspended load of the North Brazil Current and sediment from\\u000a several smaller rivers.

  18. Geochemical studies of clay minerals III. The determination of free silica and free alumina in montmorillonites

    USGS Publications Warehouse

    Foster, M.D.

    1953-01-01

    Determination of free silica by the method proposed made possible the derivation of logical formulas for several specimens of montmorillonites for which the formulas could not be derived from the analyses alone. Other montmorillonites, for which logical formulas could be derived from their analyses, were found to contain small amounts of free silica or free alumina. Others were found to contain neither free silica nor free alumina. The method consists of the following steps: (1) digestion of 1 g of the specimen with 0.5 N NaOH solution in a covered platinum crucible or dish on a steam bath for 4 hrs, stirring the mixture at 30-min intervals, (2) filtration of the undissolved material, followed by washing several times with 1% NaOH solution, (3) neutralization of the filtrate with HCl, addition of 5 ml HCl in excess and determination of SiO and Al2O3 in the usual way and (4) calculation of the amount of free SiO2 or free Al2O3 if any and the amount of attack of the clay structure by the treatment from the ratio of SiO2 to Al2O3 dissolved and the ratio of SiO2 to Al2O3 obtained on analysis. Tests with 5% Na2CO3 solution, the reagent formerly used for the solution of free SiO2 in rocks and minerals, showed that solution of opal by this reagent is always fractional, never complete, no matter how small the amount present or how long the period of treatment. Re-treatment of the sample results in 90-95% solution if 10 mg or less of opal is present, but for larger amounts of opal the percentage dissolved decreases as the amount present increases. On the other hand, 75 ml of 0.5 N NaOH completely dissolves as much as 400 mg of opal in 4 hrs digestion in a covered platinum crucible or dish, on a steam bath. However, a weaker solution or a shorter period of digestion does not effect complete solution. The same amount (75 ml) of 0.5 N NaOH also dissolves 90 mg of cristobalite and 57 mg of quartz having a grain size of less than 2 microns. Use of NaOH also permits determination of the amount of alumina dissolved, and estimation of the extent to which the clay structure was attacked by the treatment. ?? 1953.

  19. Deformation characteristics and associated clay-mineral variation in 2-3 km buried Hota accretionary complex, central Japan

    NASA Astrophysics Data System (ADS)

    Yamamoto, Y.; Kameda, J.; Yamaguchi, H.

    2009-12-01

    Although deformation and physical/chemical properties variation in aseismic-seismic transition zone were essential to examine critical changes in environmental parameters that result in earthquake, they are poorly understood because the appropriate samples buried 2-4 km have not been collected yet (scientific drilling has never reached there and most of ancient examples experienced the deeper burial depth and suffered thermal and physical overprinting). The lower to middle Miocene Hota accretionary complex is a unique example of on land accretionary complex, representing deformation and its physical/chemical properties of sediments just prior to entering the seismogenic realm. The maximum paleotemperature was estimated approximately 55-70°C (based on vitrinite reflectance) indicative of a maximum burial depth about 2-3 km assuming a paleo-geothermal gradient as 25-35°C/km. Accretionary complex in this temperature/depth range corresponds with an intermediate range between the core samples collected from the modern accretionary prism (e.g. Nankai, Barbados, and so on) and rocks in the ancient accretionary complexes on land. This presentation will treat the detailed structural and chemical analyses of the Hota accretionary complex to construct deformation properties of décollement zone and accretionary complex in its 2-3 km depth range and to discuss the interrelation between the early diagenesis (hydrocarbon/cations generation and sediment dewatering, etc.) and transition of the deformation properties. The deformation in this accretionary complex is characterized by two deformation styles: one is a few centimeter-scale phacoidal deformation representing clay minerals preferred orientation in the outer rim, whereas random fabric in the core, quite similar texture to the rocks in the present-Nankai décollement. The other is S-C style deformation (similar deformation to the mélanges in ancient accretionary complex on land) exhibiting block-in-matrix texture and quite intense clay minerals preferred orientation in the matrix, cutting the phacoidal deformation. The host and faulted (S-C structure) rocks composed of hemipelagic siltstone containing 70-80% of clay minerals. Considerable-smectite reduction and positive anomaly of illite/smectite ratio were clearly identified inside the latter S-C structure, which would cause remarkable increase in friction coefficient. Such strain hardening associated with dynamic clay-mineral variation would be the primary mechanism in décollement -zone and/or mélange-zone thickening and fundamental mechanical transition just prior to entering the seismogenic zone. Positive anomaly of the vitrinite reflectance data (Ro) inside infers frictional heating during the deformation plausibly caused the clay mineral variation.

  20. Glacial cycle and precessional period of clay mineral assemblage during late Quaternary in the Western Equatorial Pacific

    NASA Astrophysics Data System (ADS)

    Wu, J.; Liu, Z.; Zhou, C.

    2011-12-01

    Clay mineralogy, coupled with oxygen isotope records and elemental XRF scanning data, have been conducted on Core KX21-2 recovered from the Ontong Java Plateau, Western Equatorial Pacific. The clay mineral assemblage over the last 370 kyr displays strong glacial-interglacial cyclicity, with higher contents of smectite (average 76%), lower contents of chlorite (10%), illite (8%) and kaolinite (6%) during glacials, and vice versa. Fe mainly originates from smectite, and has therefore been used to represent it. In addition to glacial cycle (100 ka), spectral analysis reveals that Fe contents also display precessional period (26.8 ka and 14.4 ka). The question is, why and how the features of high-latitude and tropical-process could be exhibited in concert? The clay mineral assemblage dominating by smectite is detrital, and derived from river sediment of New Guinea, though possibly minor Asian dust. Fluctuation of sea-level combined with contrasting styles of Source-to-Sink in New Guinea cause the glacial-interglacial cycles of clay mineral assemblage. Regardless of sea-level, river sediments can travel across the narrow shelves off the northern New Guinea and then inject directly into New Guinea Coastal Undercurrent, which finally contribute Equatorial Undercurrent. In contrast, when the sea-level were high, only few sediment could be transported from southern New Guinea to the Western Equatorial Pacific, possibly by surface current. Considering the positive correlation between contents of smectite and feldspar/quartz ratios, we conclude that, because of the limitation of weathering time, the contents of smectite essentially indicate the intensity of mechanical erosion, responding to the river runoff and precipitation. Furthermore, due to the regional precipitation pattern is under control of ITCZ, these variations of smectite reflect the meridional migration of ITCZ, indirectly.

  1. Carbonation of Clay Minerals Exposed to scCO2/Water at 200 degrees and 250 degrees C

    SciTech Connect

    Sugama, T.; Ecker, L.; Gill, S.; Butcher, T. (BNL); Bour, D. (AltaRock Energy, Inc.)

    2010-11-01

    To clarify the mechanisms of carbonation of clay minerals, such as bentonite, kaolinite, and soft clay, we exposed them to supercritical carbon dioxide (scCO2)/water at temperatures of 200 and 250 C and pressures of 1500 and 2000 psi for 72- and 107-hours. Bentonite, comprising three crystalline phases, montmorillonite (MMT), anorthoclase-type albite, and quartz was susceptible to reactions with ionic carbonic acid yielded by the interactions between scCO2 and water, particularly MMT and anorthoclase-type albite phases. For MMT, the cation-exchangeable ions, such as Na+ and Ca2+, present in its basal interplanar space, were replaced by proton, H+, from ionic carbonic acid; thereafter, the cations leaching from MMT directly reacted with CO32- as a counter ion of H+ to form carbonate compounds. Such in-situ carbonation process in basal space caused the shrinkage and breakage of the spacing structure within MMT. In contrast, the wet carbonation of anorthoclase-type albite, categorized as rock minerals, entailed the formation of three amorphous by-products, such as carbonates, kaolinite-like compounds, and silicon dioxide. Together, these two different carbonations caused the disintegration and corruption of bentonite. Kaolinite clay containing the amorphous carbonates and silicon dioxide was inert to wet carbonation. We noted only a gain in weight due to its water uptake, suggesting that kaolinite-like by-products generated by the wet carbonation of rock minerals might remain unchanged even during extended exposure. Soft clay consisting of two crystalline phases, dolomite and silicon dioxide, also was unaltered by wet carbonation, despite the uptake of water.

  2. Trace element abundances in major minerals of Late Permian coals from southwestern Guizhou province, China

    USGS Publications Warehouse

    Zhang, J.; Ren, D.; Zheng, C.; Zeng, R.; Chou, C.-L.; Liu, J.

    2002-01-01

    Fourteen samples of minerals were separated by handpicking from Late Permian coals in southwestern Guizhou province, China. These 14 minerals were nodular pyrite, massive recrystallized pyrite, pyrite deposited from low-temperature hydrothermal fluid and from ground water; clay minerals; and calcite deposited from low-temperature hydrothermal fluid and from ground water. The mineralogy, elemental composition, and distribution of 33 elements in these samples were studied by optical microscopy, scanning electron microscope equipped with energy-dispersive X-ray spectrometer (SEM-EDX), X-ray diffraction (XRD), cold-vapor atomic absorption spectrometry (CV-AAS), atomic fluorescence spectrometry (AFS), inductively coupled-plasma mass spectrometry (ICP-MS), and ion-selective electrode (ISE). The results show that various minerals in coal contain variable amounts of trace elements. Clay minerals have high concentrations of Ba, Be, Cs, F, Ga, Nb, Rb, Th, U, and Zr. Quartz has little contribution to the concentration of trace elements in bulk coal. Arsenic, Mn, and Sr are in high concentrations in calcite. Pyrite has high concentrations of As, Cd, Hg, Mo, Sb, Se, Tl, and Zn. Different genetic types of calcite in coal can accumulate different trace elements; for example Ba, Co, Cr, Hg, Ni, Rb, Sn, Sr, and Zn are in higher concentrations in calcite deposited from low-temperature hydrothermal fluid than in that deposited from ground water. Furthermore, the concentrations of some trace elements are quite variable in pyrite; different genetic types of pyrites (Py-A, B, C, D) have different concentrations of trace elements, and the concentrations of trace elements are also different in pyrite of low-temperature hydrothermal origin collected from different locations. The study shows that elemental concentration is rather uniform in a pyrite vein. There are many micron and submicron mosaic pyrites in a pyrite vein, which is enriched in some trace elements, such as As and Mo. The content of trace element in pyrite vein depends upon the content of mosaic pyrite and of trace elements in it. Many environmentally sensitive trace elements are mainly contained in the minerals in coal, and hence the physical coal cleaning techniques can remove minerals from coal and decrease the emissions of potentially hazardous trace elements. ?? 2002 Elsevier Science B.V. All rights reserved.

  3. A recommended procedure for the preparation of oriented clay-mineral specimens for X-ray diffraction analysis; modifications to Drever's filter-membrane peel technique

    USGS Publications Warehouse

    Pollastro, R.M.

    1982-01-01

    Extremely well-oriented clay mineral mounts for X-ray diffraction analysis can be prepared quickly and without introducing segregation using the filter-membrane peel technique. Mounting problems encountered with smectite-rich samples can be resolved by using minimal sample and partial air-drying of the clay film before transfer to a glass slide. Samples containing small quantities of clay can produce useful oriented specimens if Teflon masks having more restrictive areas are inserted above the membrane filter during clay deposition. War]page and thermal shock of glass slides can be controlled by using a flat, porous, ceramic plate as a holding surface during heat treatments.

  4. Detection of Soluble and Fixed NH4+ in Clay Minerals by DTA and IR Reflectance Spectroscopy : A Potential Tool for Planetary Surface Exploration

    NASA Technical Reports Server (NTRS)

    Janice, Bishop; Banin, A.; Mancinelli, R. L.; Klovstad, M. R.; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    Nitrogen is an essential element for life. It is the only element among the six major biogenic elements, C, O, S, O, P, H, whose presence in the Martian soil has not been positively and directly established. We describe here a study assessing the ability to detect NH4 in soils by two methods: differential thermal analysis (DTA) and infrared (IR) reflectance spectroscopy. Four standard clay minerals (kaolinite, montmorillonite, illite and attapulgite) and an altered tephra sample from Mauna Kea were treated with NH4 in this study. Samples of the NH4-treated and leached clays were analyzed by DTA and infrared (IR) reflectance spectroscopy to quantify the delectability of soluble and sorbed/fixed NH4. An exotherm at 270-280 C was clearly detected in the DTA curves of NH4-treated (non-leached) samples. This feature is assigned to the thermal decomposition reaction of NH4. Spectral bands observed at 1.56, 2.05, 2.12, 3.06, 3.3, 3.5, 5.7 and 7.0 microns in the reflectance spectra of NH4-treated and leached samples are assigned to the sorbed/fixed ammonium in the clays. The montmorillonite has shown the most intense absorbance due to fixed ammonium among the leached samples in this study, as a result of its high cation sorption capacity. It is concluded that the presence of sorbed or fixed NH4 in clays may be detected by infrared (IR) reflectance or emission spectroscopy. Distinction between soluble and sorbed NH4 may be achieved through the presence or absence of several spectral features assigned to the sorbed NH4 moietyi and, specifically, by use of the 4.2 micrometer feature assigned to solution NH4. Thermal analyses furnish supporting evidence of ammonia in our study through detection of N released at temperatures of 270-330 C. Based on these results it is estimated that IR spectra measured from a rover should be able to detect ammonia if present above 20 mg NH4/g sample in the surface layers. Orbital IR spectra and thermal analyses measured on a rover may be able to detect ammonia in soils as well but at higher abundances. The spectral features at 3.06 and 7.0 microns due to bound NH4 in clays and altered Hawaiian tephra appear to be the most promising for detection by orbital spectrometers. If N species are present on Mars the sedimentary deposits may be the best regions to look for them.

  5. Attenuation of pollutants in municipal landfill leachate by clay minerals. Final report Dec 72Aug 75

    Microsoft Academic Search

    R. A. Griffin; N. F. Shimp

    1978-01-01

    The first part of this project was a laboratory column study of attenuation of pollutants in municipal solid waste landfill leachate by mixtures of sand and calcium-saturated clays. K, NH4, Mg, Si, and Fe were moderately attenuated; and the heavy metals Pb, Cd, Hg, and Zn were strongly attenuated even in columns with small amounts of clay. Precipitation was the

  6. Variability of Precipitation in Southern California During the Late Quaternary: Inferences From Clay Mineral Assemblages of the Santa Barbara Basin (Images Core MD02-2503)

    NASA Astrophysics Data System (ADS)

    Robert, C.; Tourneur, F.; Chamley, H.

    2003-12-01

    Clay mineral assemblages have been investigated in a late Quaternary sequence cored in the deepest (569m) part of the semi-enclosed Santa Barbara Basin, off Southern California. Core MD02-2503 consists of 45.27m of silty clay, nannofossil silty clay, and nannofossil clay, ranging from dark olive and dark olive grey to dark grey and very dark grey. The sediment is mostly laminated from top to 15.50m and from 18.00m to 21.00m, and massive to slightly bioturbated in other parts with rare laminated intervals below 32.00m. The distribution of laminated intervals in MD 02-2503 and ODP Site 893 nearby is very comparable and suggests an age of approximately 32ka at the bottom of the core. Smectite dominates the clay assemblages and is associated with abundant illite, kaolinite and chlorite being present in low contents. Smectite is especially abundant in the terrigenous load of the Santa Clara river, which drains the semi-arid continental interior of the Transverse Range. Illite is more abundant in the terrigenous load of the Ventura river and short intermittent rivers, as well as in the suspended load of the Santa Ynez river Northwest of the Santa Barbara Basin. The Santa Clara river is the largest source of terrigenous sediment of Southern California and by far the major contributor to the sedimentation of the Santa Barbara Basin, especially during intervals of intense precipitation. The content of smectite in Core MD 02-2503 is used as a tracer of the terrigenous discharges of the Santa Clara river, and related regional precipitation. Their variations are better expressed through relative abundances of smectite and illite (S/I index). Maximum values of the S/I index express intervals of intense precipitation and river discharge, whereas low values of the S/I index express more arid conditions. The S/I index increased from 28ka to 26.5ka and after 21.5ka, suggesting that precipitation intensified in Southern California during an interval marked by a warming of Pacific surface waters, increased lake level in Death Valley and the Mojave area, and glacier advances in the Sierra Nevada. Peak values of the S/I index interpreted as short intervals of maximum precipitation between 19.5ka and 12.5-13ka occurred during the Tioga Glaciation of the Sierra Nevada, and finished in coincidence with the end of Mojave lacustrine episodes and with vegetational changes (decline of pine and stabilization of oak) in the Santa Barbara area. A further interval of intermittently high S/I and intensified precipitation from 10ka to 6.5ka coincides with lacustrine development and oscillations in the California hinterland. Low values of the S/I index after 6.5ka, suggest little precipitation in Southern California as lakes dessicated in the continental interior. A further decrease of S/I and inferred precipitation at 2.8ka to 3.0ka marked the onset of modern conditions in the Santa Barbara area. Major increases of precipitation in the Santa Barbara area coincide with important climatic events: increase of West Pacific surface temperature at 26-28ka, peak of the last glaciation at 21ka, early Holocene moisture and formation of Mediterranean sapropel S1 from 10ka to 6.5ka. The decrease of precipitation after 6.5ka coincides with the development of aridity in the thirties of latitude worldwide.

  7. [X-ray powder diffraction of clay minerals of SZK01 core of Zabuye Lake, Tibetan Plateau].

    PubMed

    Zhang, Xue-Fei; Zheng, Mian-Ping

    2014-11-01

    The present article chooses the core from the borehole SZK01 in Zabuye Lake as the main research object. According to the results of X-ray powder diffraction of clay minerals, the major components are illite, illite and smectite mixed layer mineral (I/S), kaolinite and chlorite. According to the different species and contents of clay, integration of the characteristics of mineral and the results of ?18O, we reestablished the evolution process of paleoclimate in Zabuye Lake. In compaison with SZK02 core in Zabuye, Greenland GISP2 and GRIP and Guliya ice core, it contains 5 stages since 115 ka in Zabuye: the last interglacial (15-75.5 ka), the earlier last glacial (75.5-60 ka), the interstage of the last glacial (60-30.1 ka), the last glacial maximum (30.1-16.7 ka) and deglacial-holocene (since 16.7 ka). We also recognized 6 Heinrich events (H1-H6) and warm event in 71 ka. In particular, the content of kaolinite is low, with the negative-skewed value of ?18O in 52-53 ka, while the value of ?18O in SZK02 and Guliya ice core is negative-skewed too, indicating the cold event in Tibet plateau, named H5-1. All the above demonstrated that the climate in Tibet plateau is global since the earlier last glacial, and it also has regional characteristics. PMID:25752070

  8. Diagenesis of clay mineral assemblages in the Shikoku Basin: Inputs to the Nankai Trough megathrust and seismogenic zone

    NASA Astrophysics Data System (ADS)

    Underwood, M.; Guo, J.; Song, C.

    2012-12-01

    One of the essential components of the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) is to document the composition and diagenetic alteration of sedimentary inputs to the subduction zone of SW Japan. Two sites were drilled seaward of the trench during IODP Expeditions 322 and 333 to demonstrate how those subduction inputs have been influenced by the basement topography of Shikoku Basin. Site C0011 was drilled on the NW flank of Kashinosaki Knoll, and Site C0012 is located near the seamount's summit. The lithostratigraphy expands and condenses from site to site, but the clay mineral assemblages are nearly identical when comparisons are made among coeval units. The early history of sedimentation (middle to late Miocene) was dominated by expandable clay minerals of the smectite group. Contents of smectite in strata older than 5.3 Ma typically exceed 65% of the clay-size fraction, and there are dozens of bentonite layers (altered volcanic ash) interbedded with the hemipelagic mudstones and turbidites. Those percentages amount to >45 wt-% smectite in the bulk mudstone. Volcanic sources for the Miocene clay probably included the ancestral Izu-Bonin island arc, the Izu-Honshu collision zone, and anomalous near-trench magma bodies in the Outer Zone of Honshu and Shikoku Island. As sedimentation progressed into the Pliocene and Pleistocene, mud supplies to the Shikoku Basin shifted increasingly to detrital illite and chlorite eroded from the uplifted accretionary complex (Outer Zone). At Site C0011, the younger hemipelagic-pyroclastic facies (upper Shikoku Basin) contains an average of 43% smectite, 36% illite, and 18% kaolinite + chlorite in the clay-size fraction. At Site C0012, comparable values are S = 51%, I = 32%, and K+C = 14%. XRD results show no evidence of smectite-to-illite diagenesis seaward of the trench, although it is important to note that Site C0011 was abandoned before reaching basaltic basement. We can predict the extent of smectite-to-illite diagenesis using simple kinetic models that account for differences in heat flow from the flank to the summit of Kashinosaki Knoll and rapid burial of Shikoku Basin facies beneath the Quaternary trench wedge. Our modeling results support the notion that illitization does not progress to detectable levels (>20% I in mixed-layer clay) until after the Shikoku Basin deposits are subducted beneath the frontal megathrust. That absence of pre-subduction diagenesis is important to consider when assessing the potential for fluid production and fluid overpressures deeper down-dip along the megathrust, as well as for identifying the potential sources for freshening of interstitial fluids.

  9. Comparison of manure compost and mineral fertilizer for hybrid poplar plantation establishment on boreal heavy clay soils

    Microsoft Academic Search

    Marie Larcheveque; Annie Desrochers; Guy R. Larocque

    • Introduction\\u000a    Clay soils are typically rich in nutrients but are often compact and hard during summer increasing planting shock by limiting\\u000a root development. Recycling farm manure in hybrid poplar plantations may offer additional benefits to mineral fertilizer as\\u000a organic amendment can create better conditions for the early development of roots in addition to nutrient release.\\u000a \\u000a \\u000a \\u000a \\u000a • Material and

  10. Detection and Quantification of Expansive Clay Minerals in Geologically-Diverse Texas Aggregate Fines 

    E-print Network

    Russell, George 1983-

    2012-11-28

    diffraction patterns. Methylene blue adsorption (MBA) and cation exchange capacity (CEC) of clay fractions (< 2µm) and -40 mesh screenings (< 400 µm) were determined for most aggregates. Many of the aggregates exhibited significant quantities of expansive...

  11. Influence of Biogenic Fe(II) on the Extent of Microbial Reduction of Fe(III) in Clay Minerals Nontronite, Illite, and Chlorite

    SciTech Connect

    Jaisi, Deb P.; Dong, Hailiang; Liu, Chongxuan

    2007-03-01

    Microbial reduction of Fe(III) in clay minerals is an important process that affects properties of clay-rich materials and iron biogeochemical cycling in natural environments. Microbial reduction often ceases before all Fe(III) in clay minerals is exhausted. The factors causing the cessation are, however, not well understood. The objective of this study was to assess the role of biogenic Fe(II) in microbial reduction of Fe(III) in various clay minerals. Bioreduction experiments were performed in a batch system, where lactate was used as the sole electron donor, Fe(III) in clay minerals as the sole electron acceptor, and Shewanella putrefaciens CN32 as the mediator with and without an electron shuttle AQDS. Our results showed that bioreduction activity ceased within two weeks with variable extents of bioreduction of structural Fe(III) in clay minerals. When fresh CN32 cells were added to the old cultures (6 months), bioreduction resumed and extents increased. This result indicated that the previous cessation of Fe(III) bioreduction was not necessarily due to the exhaustion of bioavailable Fe(III) in the mineral structure, and suggested that the changes of cell physiology or solution chemistry, such as Fe(II) production during microbial reduction, affected the extent of bioreduction. To investigate the effect of Fe(II) production on Fe(III) bioreduction, a typical bioreduction process (consisting of lactate, clay, cells and AQDS) was separated into two steps: 1. AQDS was reduced by cells in the absence of clay but in the presence of variable Fe(II) concentrations; 2. reduction of Fe(III) in clays by biogenic AH2DS in the absence of cells. The inhibitory effect of Fe(II) on CN32 activity was confirmed. TEM analysis revealed a thick electron dense halo surrounding the cell surfaces that most likely resulted from Fe(II) sorption/precipitation. Such electron dense materials might have blocked or interfered electron transfers on cell surfaces. The inhibitory effect of Fe(II) was also observed in AH2DS reduction of clay Fe(III). The reduction extent consistently decreased with an increasing concentration of presorbed Fe(II) (onto clay surfaces) at the start of reduction experiments. The relative reduction extent (i.e., reduction extent after normalization to the reduction extent when spiked Fe(II) was zero) was similar for all clay minerals studied and showed a systematic decrease with increasing clay-sorbed Fe(II) concentration. These results suggest a similar inhibitory effect of clay-sorbed Fe(II) on the reduction extent for different clay minerals. An equilibrium thermodynamic model was established with independently estimated parameters to evaluate whether the cessation of Fe(III) reduction by AH2DS was due to the exhaustion of reaction free energy. Model-calculated reduction extents were, however, over 50% higher than experimentally measured, indicating that other factors, such as blockage of the electron transfer chain and mineralogy, restricted the reduction extent. This study also revealed that the relative reducibility of Fe(III) in different clay was as follows: nontronite > chlorite > illite. This order is qualitatively consistent with the differences in crystal chemistry of these minerals.

  12. Analysis of organic matter by flash pyrolysis-gas chromatography–mass spectrometry in the presence of Na-smectite: When clay minerals lead to identical molecular signature

    Microsoft Academic Search

    Pierre Faure; Laurent Jeanneau; Frederic Lannuzel

    2006-01-01

    Different studies have already pointed out the influence of clays during the analysis of pure organic compounds (especially alkanols, alkanoic acids) as well as macromolecules (humic acids) by flash pyrolysis-gas chromatography–mass spectrometry (PyGC–MS). Especially, the occurrence of clay minerals favors the generation of aromatic units such as alkylbenzenes and polycyclic aromatic hydrocarbons. So as to better identify the nature of

  13. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2000-01-01

    Part of the 1999 Industrial Minerals Review. The state of the ball clay industry in 1999 is presented. Record highs in the sales and use of ball clay were attained in 1999 due to the continued strength of the U.S. economy. U.S. production was estimated at 1.25 million st for the year, with more than half of that amount mined in Tennessee. Details of the consumption, price, imports, and exports of ball clay in 1999 and the outlook for ball clay over the next few years are provided.

  14. Adsorption mechanisms of emerging micro-pollutants with a clay mineral: Case of tramadol and doxepine pharmaceutical products.

    PubMed

    Thiebault, Thomas; Guégan, Régis; Boussafir, Mohammed

    2015-09-01

    A sodium exchanged smectite clay mineral (Mt) was used as geo-sorbent for the adsorption of tramadol and doxepin: two pharmaceutical products (PPs) defined as emerging pollutants due to their presence at significant concentration in numerous water compartments. The adsorption isotherms for both the temperatures of 20 and 40°C and the derived data determined through the fitting procedure by using Langmuir, Freundlich and Dubinin-Radushkevich equation models explicitly pointed out that the sorption of both tramadol and doxepin is mainly driven by electrostatic interaction. The studied PPs are intercalated in a monolayer arrangement within the interlayer space through a cation exchange in stoichiometric proportion with the Na(+) cations leading to adsorbed PPs amounts that match the cation exchange capacity (CEC) of Mt. Due to their hydrophobic character, additional doxepin molecules could be adsorbed by weak molecular interaction driving to an increase of the adsorbed amount beyond the CEC at low temperature (20°C). The confinement of PPs within the interlayer space of Mt confirms the use of clay minerals as potential material for the wastewater treatment as well as it drives to an amorphous or glassy state, which can find echo in biopharmaceutical applications for a controlled release of PPs. PMID:25950945

  15. The 1.7- to 4.2-micron spectrum of asteroid 1 Ceres - Evidence for structural water in clay minerals

    NASA Technical Reports Server (NTRS)

    Lebofsky, L. A.; Feierberg, M. A.; Larson, H. P.; Johnson, J. R.; Tokunaga, A. T.

    1981-01-01

    A high-resolution Fourier spectrum (1.7-3.5 microns) and medium-resolution spectrophotometry (2.7-4.2 microns) were obtained for Asteroid 1 Ceres. The presence of the 3-micron absorption feature due to water of hydration was confirmed. The 3-micron feature is compared with the 3-micron bands due to water of hydration in clays and salts. It is concluded that the spectrum of Ceres shows a strong absorption at 2.7-2.8 microns due to structural OH groups in clay minerals. The dominant minerals on the surface of Ceres are therefore hydrated clay minerals structurally similar to terrestrial montmorillonites. There is also a narrow absorption feature at 3.1 microns which is attributable to a very small amount of water ice on Ceres. This is the first evidence for ice on the surface of an asteroid.

  16. Crystal growth of a layered silicate clay mineral as revealed by atomic force microscopy

    SciTech Connect

    Carrado, K.A.; Song, Kang [Argonne National Lab., IL (United States); Zajac, G.W. [Amoco Research Center, Naperville, IL (United States)

    1997-12-31

    Non-contact atomic force microscopy, commonly referred to as {open_quotes}tapping mode{close_quotes} AFM, has been used to scan primarily the morphological features of growing hectorite clay crystallites synthesized in the presence of organo-ammonium cations. The use of such cations allows larger crystals to form in this system, making study by AFM feasible. This is the first time that actual temporal {open_quotes}snapshots{close_quotes} of a clay`s nucleation and crystallization processes have been presented. The observed view does not support the perhaps predicted scene of small crystallites slowly ripening into larger and larger plates. Instead, larger and larger aggregates appear to coalesce from a larger number of small crystallites that are closely associated in globular networks similar in appearance to {open_quotes}strings of pearls{close_quotes} at the initial stages of crystallization.

  17. Suitability of the methylene blue test for determination of cation exchange capacity of clay minerals related to ammonium acetate method

    NASA Astrophysics Data System (ADS)

    Miloševi?, Maja; Logar, Mihovil; Doj?inovi?, Biljana; Eri?, Suzana

    2015-04-01

    Cation exchange capacity (CEC) represents one of the most important parameters of clay minerals which reflects their ability to exchange cations with liquid phases in near contact. Measurement of CEC is used for characterizing sample plasticity, adsorbing and swelling properties which later define their usage in industrial purposes. Several methods have been developed over the years for determination of layer charge, charge density, charge distribution, etc. and have been published in numerous papers (Czimerova et al., 2006; Yukselen and Kaya, 2008). The main goal of present study is comparison of suitability of more recent method - methylene blue test in regard to older method - ammonium acetate for determination of CEC. For this study, we selected one montmorillonite clay (Bogovina, Serbia) and two mainly kaolinite clays (Mili?inica, Serbia). Chemicals used for CEC determinations were solution of methylene blue (MB)(14*10-6M/ml) and ammonium acetate (AA) solution (1M). The obtained results are showing generally lower values in case of MB method. The main difference is due to molecular aggregation of MB on the clay surface. AA method is highly sensitive to the presence of CaO. Release of Ca ion from the sample into the solution can limit the saturation of exchange sites by the ammonium ion. This is clearly visible in case of montmorillonite clay. Fe2+ and Mg ions are difficult to move by the ammonium ion because of their ion radius, but in case of MB molecule there is no such restriction in removing them from the exchange sites. MB solution, even in a low concentration (2*10-6M/ml), is showing preferable results in moving the ions from their positions which is already visible after adding a small quantity of solution (25cm3). Both MB-titration and MB-spot test yield similar results and are much simpler methods than AA and they also give other information such as specific surface area (external and internal) whereas AA method only provides information about cations in exchangeable positions. Both methods, methylene blue test and ammonium acetate method, have advantages and disadvantages and differ in their requirements for the sample preparations but in general method selection is depending on the specific application of the given sample. References: - Yukselen, Y. and Kaya, A., Engineering Geology 102 (2008) 38-45 - Czimerova, A., Bujdak, J. and Dohrmann, R., Applied Clay Science 34 (2006) 2-13

  18. Influence of Environmental Factors on Antagonism of Fungi by Bacteria in Soil: Clay Minerals and pH

    PubMed Central

    Rosenzweig, William D.; Stotzky, G.

    1979-01-01

    The soil replica plating technique was used to evaluate the influence of clay minerals and pH on antagonistic interactions between fungi and bacteria in soil. In general, the antagonistic activity of bacteria towards filamentous fungi was greater in soil than on agar. The spread of Aspergillus niger through soil was inhibited by Serratia marcescens when the organisms were inoculated into separate sites in soil, and this antagonistic effect was maintained when the soil was amended with 3, 6, 9, or 12% (vol/vol) montmorillonite, whereas the addition of kaolinite at a concentration of 3% reduced the antagonism and at 6, 9, or 12% totally eliminated it. Similar results were obtained with the inhibition of A. niger by Agrobacterium radiobacter and of Penicillium vermiculatum by either S. marcescens or Nocardia paraffinae. When A. niger and S. marcescens were inoculated into the same soil site, A. niger was inhibited in all soils, regardless of clay content, although the extent of inhibition was greater as the concentration of montmorillonite, but not of kaolinite, increased. A. niger was inhibited more when inoculated as spores than as mycelial fragments and when inoculated 96 h after S. marcescens, but a 1% glucose solution reduced the amount of inhibition when the fungus was inoculated 96 h after the bacterium. When the pH of the soil-clay mixtures was altered, the amount of antagonism usually increased as the pH increased. Antagonism appeared to be related to the cation-exchange capacity and the pH of the soil-clay mixtures. Bacillus cereus and another species of Bacillus showed no activity in soil towards A. niger under any of the environmental conditions tested, even though the Bacillus sp. significantly inhibited A. niger and seven other fungi on agar. PMID:16345477

  19. Clay-mineral and grain-size distributions in surface sediments of the White Sea (Arctic Ocean): indicators of sediment sources and transport processes

    NASA Astrophysics Data System (ADS)

    Saukel, Cornelia; Stein, Rüdiger; Vogt, Christoph; Shevchenko, Vladimir P.

    2010-12-01

    In this study, the grain-size and clay-mineral compositions of 73 surface sediment samples collected in a variety of environmental settings in the White Sea are presented to characterize recent sedimentation processes, reconstruct transport pathways, and identify potential source areas of the terrigenous components. Areas >100 m deep are invariably characterized by silty clay, whereas areas <100 m deep exhibit more heterogeneous grain-size compositions plausibly explained by coastal erosion and (re-)distribution mechanisms, particularly tidal currents. The dominance of sand in the estuarine areas of the Onega and Dvina rivers as well as toward the Gorlo Strait connecting the White Sea with the Barents Sea is attributed to increased current speeds. Illite and smectite are the dominant clay minerals in recent sediments of the southwestern and eastern White Sea sectors, respectively. Their distribution patterns largely depend on the geology of the source areas, and mirror surface circulation patterns, especially in Dvina Bay. Smectite is a key clay mineral in White Sea surface sediments, as it reveals the dominating influence of the Northern Dvina's runoff on sedimentation and water circulation throughout the basin. In comparison to other Eurasian shelf seas, the White Sea is characterized by a greater diversity of clay-mineral assemblages, which range from illite- to smectite-dominated sectors containing variable amounts of chlorite and kaolinite.

  20. An improved radiative transfer model for estimating mineral abundance of immature and mature lunar soils

    NASA Astrophysics Data System (ADS)

    Liu, Dawei; Li, Lin; Sun, Ying

    2015-06-01

    An improved Hapke's radiative transfer model (RTM) is presented to estimate mineral abundance for both immature and mature lunar soils from the Lunar Soil Characterization Consortium (LSCC) dataset. Fundamental to this improved Hapke's model is the application of an alternative equation to describe the effects of larger size submicroscopic metallic iron (SMFe) (>50 nm) in the interior of agglutinitic glass that mainly darken the host material, contrasting to the darkening and reddening effects of smaller size SMFe (<50 nm) residing in the rims of mineral grains. Results from applying a nonlinear inversion procedure to the improved Hapke's RTM show that the average mass fraction of smaller and larger size SMFe in lunar soils was estimated to be 0.30% and 0.31% respectively, and the particle size distribution of soil samples is all within their measured range. Based on the derived mass fraction of SMFe and particle size of the soil samples, abundances of end-member components composing lunar soil samples were derived via minimizing the difference between measured and calculated spectra. The root mean square error (RMSE) between the fitted and measured spectra is lower than 0.01 for highland samples and 0.005 for mare samples. This improved Hapke's model accurately estimates abundances of agglutinitic glass (R-squared = 0.88), pyroxene (R-squared = 0.69) and plagioclase (R-squared = 0.95) for all 57 samples used in this study including both immature and mature lunar soils. However, the improved Hapke's RTM shows poor performance for quantifying abundances of olivine, ilmenite and volcanic glass. Improving the model performance for estimation of these three end-member components is the central focus for our future work.

  1. ROLE OF CLAY MINERALS ON SOIL ORGANIC MATTER FORMATION AND STABILIZATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Maillard reaction, as an alternative theory for soil organic matter (SOM) formation, has not been investigated under conditions relevant for SOM formation. This research was conducted to investigate the distribution of newly formed humic materials into mineralogical distinct clay-size fractions...

  2. The Determination of Surface Basicity of the Oxygen Planes of Expanding Clay Minerals by Acridine Orange

    Microsoft Academic Search

    Diana Garfinkel-Shweky; Shmuel Yariv

    1997-01-01

    The surface basicity of the oxygen planes of four Na–smectites and one Na–vermiculite was studied by visible spectroscopy of clay suspensions saturated with the metachromic cationic dye acridine orange. A metachromic band in the spectrum is an indication of ? interactions in which the cationic dye is involved. Curves describing the wavelength of the metachromic band in the presence of

  3. Monte Carlo Simulation of Interlayer Molecular Structure in Swelling Clay Minerals. 2. Monolayer Hydrates

    Microsoft Academic Search

    N. T. Skipper; GARRISON SPOSITO; FANG-Ru CHOU CHANG

    1995-01-01

    Monte Carlo (MC) simulations of interlayer molecular structure in monolayer hydrates of Na- saturated Wyoming-type montmorillonites and vermiculite were performed. Detailed comparison of the stimulation results with experimental diffraction and thermodynamic data for these clay-water systems indicated good semiquantitative to quantitative agreement. The MC simulations revealed that, in the monolayer hydrate, interlayer water molecules tend to increase their occupation of

  4. Kinetics and thermodynamics studies of copper exchange on Na–montmorillonite clay mineral

    Microsoft Academic Search

    Mervette El-Batouti; Olfat M. Sadek; Fayez F. Assaad

    2003-01-01

    The kinetics of Cu ion exchange on Na–montmorillonite clay has been investigated at 20, 30, and 40°C in water, methanol, and ethanol. The reaction is endothermic in nature. Solvent effects on the reaction rate have been discussed. The thermodynamic activation parameters were calculated and discussed in terms of solvation effects. A multiple reaction rate order equation was used to describe

  5. ADSORPTION, DESORPTION AND OXIDATION OF ARSENIC AFFECTED BY CLAY MINERALS AND AGING PROCESS

    EPA Science Inventory

    Adsorption/desorption and oxidation/reduction of arsenic at clay surfaces are very important to the natural attenuation of arsenic in the subsurface environment. Although numerous studies have concluded that iron oxides have high affinities for the adsorption of As(V), very litt...

  6. Evolution of major mineral compositions and trace element abundances during fractional crystallization of a model lunar composition

    NASA Technical Reports Server (NTRS)

    Drake, M. J.

    1976-01-01

    The evolution of major mineral compositions and trace element abundances during perfect fractional crystallization of a model lunar magma ocean was calculated. The minerals in the model lunar composition were olivine, orthopyroxene, clinopyroxene, and plagioclase. Lunar bulk composition data, major mineral/melt equilibria data, and trace element partition data were taken from published sources. The results show olivine beginning to crystallize at 1380 C. Approximately 50% of the system crystallizes as olivine. From 50 to 60% solidification, orthopyroxene crystallizes alone. During the final 40% solidification, Ca-rich clinopyroxene and plagioclase crystallize together. Various changes in composition of all these minerals are also noted during the process. Concomitant evolution of major element abundances in the melt is followed along with that of trace element abundances. Consequences of the results for constraints on some aspects of the composition of the lunar magma ocean and of the primitive moon are discussed.

  7. Stability of guanine adsorbed in a clay mineral under gamma irradiation at temperatures (77 and 298 K): Implications for chemical evolution studies

    NASA Astrophysics Data System (ADS)

    Meléndez-López, A. L.; Ramos-Bernal, S.; Ramírez-Vázquez, M. L.

    2014-07-01

    Chemical evolution is a physical and chemical preamble prior the appearance of life. In these processes, clay minerals might have played an important role on the early Earth. The relevance of these solids in the emergence of life is due to their ancient origin, wide distribution, and especially, their physico-chemical properties. Clays, therefore, are considered the most likely inorganic materials to promote organic reactions in the primitive Earth. John D. Bernal suggested clays as concentrators of biological precursor molecules, as catalysis and clays might protect these molecules from high-energy radiation. On the other hand, nucleic acid bases and their derivatives are important compounds in biological systems. Their synthesis and stability in environmental conditions are of paramount importance in chemical evolution. The aim of this work is to extend the knowledge of the role of clays in the prebiotic epoch in relation to the behavior of guanine, a nucleic acid base, adsorbed in a clay mineral. To this end, we studied its adsorption in clays, its site of binding, and its survival under a high radiation field and at different temperatures and pH. The results showed guanine adsorption onto clays increased with the decreasing of the pH. This result could be explained by electrostatic forces between guanine positively charged at an acid pH and the negatively charged interlamellar channel of the clay. X-ray diffractograms showed that guanine is adsorbed onto the clay at the interlayer channel. To study the survival of guanine in a high radiation field, the system guanine-clay was irradiated under different irradiation doses, temperatures, and pH. The results showed that more than 90% of the guanine survives, and when the radiolysis is made without clay, the decomposition of this molecule occurs at low irradiation doses. The radiolysis performed at 77 K showed very low decomposition, which is important in cometary chemistry. These results show the protection role of the clay toward ionizing radiation of an organic compound adsorbed into it.

  8. Optical properties of heterogeneous nanosystems based on montmorillonite clay mineral and 5CB nematic liquid crystal

    NASA Astrophysics Data System (ADS)

    Chashechnikova, I.; Dolgov, L.; Gavrilko, T.; Puchkovska, G.; Shaydyuk, Ye.; Lebovka, N.; Moraru, V.; Baran, J.; Ratajczak, H.

    2005-06-01

    The effect of montmorillonite (MMT) clay modification with surfactant cations on the electrooptical properties of the LC-clay nanocomposites consisting of MMT and 4-pentyl-4'-cyanobiphenyl (5CB) nematic liquid crystal was investigated depending on the composite preparation method. We showed that only composites consisting of MMT modified with organic surfactants (alkylbenzyldimethylammonium chlorides with alkyl chain length C 14-C 18) display electrooptical memory effect and contrast. Adding a polar additive (acetone) to the mixture during the composite preparation considerably improves the homogeneity of the composites and their electrooptical performance. Using IR and Raman spectroscopy methods it was shown that in the LC-organoclay composites mutual interaction between the components takes place, which results in alignment of the near-surface layers of both organic and inorganic components of the composite. Due to such interaction, these systems display electrooptical contrast and memory effect. The LC-clay composites consisting of organophobic Na-MMT do not display electrooptical effect because of the absence of interaction between the components, which is confirmed by the IR and Raman spectroscopy data.

  9. Microtomographic quantification of hydraulic clay mineral displacement effects during a CO2 sequestration experiment with saline aquifer sandstone.

    PubMed

    Sell, Kathleen; Enzmann, Frieder; Kersten, Michael; Spangenberg, Erik

    2013-01-01

    We combined a noninvasive tomographic imaging technique with an invasive open-system core-flooding experiment and compared the results of the pre- and postflooded states of an experimental sandstone core sample from an ongoing field trial for carbon dioxide geosequestration. For the experiment, a rock core sample of 80 mL volume was taken from the 629 m Stuttgart Formation storage domain of a saline sandstone aquifer at the CCS research pilot plant Ketzin, Germany. Supercritical carbon dioxide and synthetical brine were injected under in situ reservoir p/T-conditions at an average flow rate of 0.1 mL/min for 256 h. X-ray computed microtomographic imaging was carried out before and after the core-flooding experiment at a spatial voxel resolution of 27 ?m. No significant changes in microstructure were found at the tomographic imaging resolution including porosity and pore size distribution, except of an increase of depositional heterogeneous distribution of clay minerals in the pores. The digitized rock data were used as direct real microstructure input to the GeoDict software package, to simulate Navier-Stokes flow by a lattice Boltzmann equation solver. This procedure yielded 3D pressure and flow velocity fields, and revealed that the migration of clay particles decreased the permeability tensor probably due to clogging of pore openings. PMID:22924476

  10. A comparison of in vitro and in vivo effect of clay minerals, humic acid and micronutrients on the activity of fungicides against Rhizoctonia solani

    Microsoft Academic Search

    Hans R. Kataria; Shyam Sunder

    1988-01-01

    Activity of nine fungicides against mycelial growth ofRhizoctonia solani in potato dextrose broth and in pot tests as seed treatment against cowpea seedling rot in infested soil was differentially in fluenced by clay minerals, humic acid and micronutrients. Humic acid, extracted from farmyard manure, considerably lowered the activity, bothin vitro andin vivo, of all fungicides except chloroneb. Montmorillonite caused substantial

  11. Effect of cadmium on fungi and on interactions between fungi and bacteria in soil: influence of clay minerals and pH

    Microsoft Academic Search

    H. Babich; G. Stotzky

    1977-01-01

    Fungi (Rhizopus stolonifer, Trichoderma viride, Fusarium oxysporum f. sp. conglutinans, Cunninghamella echinulata, and several species of Aspergillus and Penicillium) tolerated higher concentrations of cadmium (Cd) when grown in soil than when grown on laboratory media, indicating that soil mitigated the toxic effects of Cd. In soil amended with clay minerals, montmorillonite provided partial or total protection against fungistatic effects of

  12. Filtration and retention of mineral processing slurries with pumice and common clay: low-cost materials for environmental applications in the small-scale mining industry

    Microsoft Academic Search

    U. Kelm; V. Sanhueza; C. Guzman

    2003-01-01

    The sixth region of Chile hosts the giant El Teniente porphyry copper deposit and several polymetallic districts exploited in small mine works; the latter are situated and processed in a predominantly agricultural area. This mining activity has a potential for environmental damage caused by infiltration of mineral processing slurries. As possible low-cost material for environmental applications, a local common clay

  13. Implications of late Eocene to early Miocene clay mineral assemblages in McMurdo Sound (Ross Sea, Antarctica) on paleoclimate and ice dynamics

    Microsoft Academic Search

    Werner Ehrmann

    1998-01-01

    The clay mineral assemblages of upper Eocene to lower Miocene sediments recovered at the CIROS-1 and MSSTS-1 drill sites on the McMurdo Sound shelf, Antarctica, were analyzed in order to reconstruct the Cenozoic Antarctic paleoclimate and ice dynamics. The assemblages are dominated by smectite and illite, with minor amounts of chlorite and kaolinite. The highest smectite amounts and best smectite

  14. Experimental Determination of Clay Mineral Reactions in Clastic Reservoir Rock Resulting from the Injection of Supercritical CO2

    NASA Astrophysics Data System (ADS)

    Mangini, S. A.; Shaw, C. A.; Skidmore, M. L.

    2013-12-01

    The Cretaceous Frontier Formation of the Powder River Basin, WY has been considered as a potential reservoir for storing anthropogenic CO2. The reservoir zones are composed of fine-grained quartz and potassium feldspar rich sandstones, cemented with clay minerals (kaolinite and interlayered illite and montmorillonite). The purpose of these experiments is to determine whether susceptible minerals such as illite, montmorillonite, and potassium feldspar undergo in-situ 'weathering' reactions when exposed to the high concentrations of carbonic acid generated by the dissolution of supercritical CO2 in formation water. The transformation of these minerals has the potential to: 1.) open up pore space through dissolution; 2.) reduce pore space and/or close pore throats by precipitating new minerals, or 3.) cause little change if the reactions take place slowly. Core samples of the Frontier Formation were obtained from the USGS Core Repository in Denver, CO and their physical and mineralogical properties analyzed. Porosity and permeability of the cores have been determined by helium porosimetry and gas permeability testing. Pore space distribution was analyzed by CT scan. Mineralogy was determined by thin section analysis, X-Ray diffraction, and Scanning Electron Microscopy. Ongoing experiments will expose the cores to CO2 saturated brine in a flow-through reactor at conditions similar to those found in the subsurface (100oC and 15MPa). Changes to the chemical composition of the brine will be determined by withdrawing samples at regular intervals during the experiment and analyzing their contents with ion chromatography and colorimetry. The physical and mineralogical properties of the cores will be analyzed after each experiment and compared to the initial conditions. We will report on the results of these experiments.

  15. Retention of anhydrous ammonia as influenced by clay mineral types, cations, temperature and moisture 

    E-print Network

    McBee, George G

    1956-01-01

    (39) found amaonia increased the availability of certain cations and anions in the soil. Soil moisture has been shown by several investigators to be of importance in anhydrous ammonia retention. Blue and Eno (9, 10) found that retenti. on of ~a... in the oase of Fe. The clay suspensions used for saturation with the previously named cations had all been flocculated previously with Na01. In the case of montmorillonite, additional cwLterial had to be prepared and was then flocoulated with NaC1. ~P...

  16. High gradient magnetic separation of iron oxide minerals from soil clays 

    E-print Network

    Schulze, Darrell Gene

    1977-01-01

    steel wool, placed in a strong magnetic field (1. 6 Tesla), provides the magnetic field and magnetic field gradients necessary to trap weakly magnetic, clay size particles flowing through the filter as a dilute suspension in pH 10. 5 Na C03 solution.... Of the total dithionite-citrate-bicarbonate extractable Fe 0 in 2 3 the 2-0. 2 um size fraction of six soils, 70 to 94X was recovered in the magnetic fraction which consisted of 1. 6 to 27. 7X Fe 0 by weight. For the &0. 2 pm size fraction, 11 to 40X...

  17. Clay minerals in primitive meteorites and interplanetary dust 2. Smectites and micas

    NASA Technical Reports Server (NTRS)

    Keller, L. P.; Zolensky, M. E.

    1991-01-01

    The classification is briefly summarized of stony meteorites and cosmic dust, and the mineralogy and chemistry is described of serpentine group minerals. The occurrence of smectites and micas in extraterrestrial materials is examined. The characterization of fine grained minerals in meteorites and IDPs relies heavily on electron beam instruments, especially the transmission electron microscope (TEM). Typically, phyllosilicates are identified by a combination of high resolution imaging of basal spacings, electron diffraction, and chemical analysis. Smectites can be difficult to differentiate from micas because the smectites lose their interlayer water and the interlayer partly collapse in the high vacuum of the TEM.

  18. Chemical and physical transformations of aluminosilicate clay minerals due to acid treatment and consequences for heterogeneous ice nucleation.

    PubMed

    Sihvonen, Sarah K; Schill, Gregory P; Lyktey, Nicholas A; Veghte, Daniel P; Tolbert, Margaret A; Freedman, Miriam Arak

    2014-09-25

    Mineral dust aerosol is one of the largest contributors to global ice nuclei, but physical and chemical processing of dust during atmospheric transport can alter its ice nucleation activity. In particular, several recent studies have noted that sulfuric and nitric acids inhibit heterogeneous ice nucleation in the regime below liquid water saturation in aluminosilicate clay minerals. We have exposed kaolinite, KGa-1b and KGa-2, and montmorillonite, STx-1b and SWy-2, to aqueous sulfuric and nitric acid to determine the physical and chemical changes that are responsible for the observed deactivation. To characterize the changes to the samples upon acid treatment, we use X-ray diffraction, transmission electron microscopy, and inductively coupled plasma-atomic emission spectroscopy. We find that the reaction of kaolinite and montmorillonite with aqueous sulfuric acid results in the formation of hydrated aluminum sulfate. In addition, sulfuric and nitric acids induce large structural changes in montmorillonite. We additionally report the supersaturation with respect to ice required for the onset of ice nucleation for these acid-treated species. On the basis of lattice spacing arguments, we explain how the chemical and physical changes observed upon acid treatment could lead to the observed reduction in ice nucleation activity. PMID:25211030

  19. Bioavailability of iron in geophagic earths and clay minerals, and their effect on dietary iron absorption using an in vitro digestion/Caco-2 cell model

    PubMed Central

    Seim, Gretchen L.; Ahn, Cedric I.; Bodis, Mary S.; Luwedde, Flavia; Miller, Dennis D.; Hillier, Stephen; Tako, Elad; Glahn, Raymond P.; Young, Sera L.

    2014-01-01

    Geophagy, the deliberate consumption of earth, is strongly associated with iron (Fe) deficiency. It has been proposed that geophagy may be practiced as a means to improve Fe status by increasing Fe intakes and, conversely, that geophagy may cause Fe deficiency by inhibiting Fe absorption. We tested these hypotheses by measuring Fe concentration and relative bioavailable Fe content of 12 samples of geophagic earth and 4 samples of pure clay minerals. Further, we assessed the impact of these samples on the bioavailability of Fe from an Fe-rich test meal (cooked white beans, WB). Fe concentrations were measured with inductively coupled plasma atomic emission spectroscopy. Fe bioavailability was determined using an in vitro digestion/Caco-2 cell model in which ferritin formation was used as an index of Fe bioavailability. Geophagic earth and clay mineral samples were evaluated with this model, both alone and in combination with WB (1:16 ratio, sample:WB). Median Fe concentration of the geophagic earth was 3485 (IQR 2462, 14571) ?g/g and mean Fe concentration in the clay minerals was 2791 (± 1782) ?g/g. All specimens had Fe concentrations significantly higher (p ? 0.005) than the Fe concentration of WB (77 ?g/g). Ferritin formation (i.e. Fe uptake) in cells exposed to geophagic earths and clay minerals was significantly lower than in cells exposed to WB (p ? 0.05) and Fe uptake responses of 11 of the 16 samples were not significantly different from the blank, indicating no bioavailable Fe. When samples were combined with WB, 5 of 16 had mean ferritin levels that were significantly lower (p ? 0.05, one tail) than the WB alone, indicating that the samples inhibited Fe uptake from the WB. None of the ferritin responses of cells exposed to both WB and earth/clay were significantly higher than WB alone. Thus, although geophagic earths and mineral clays are high in total Fe, very little of this Fe is bioavailable. Further, some geophagic earth and clay mineral samples inhibit Fe absorption from foods. In vivo research is warranted to confirm these observations and to determine if geophagic earth samples can be a source of Fe and/or inhibit Fe absorption. PMID:23787405

  20. Oligomerization of glycine on clay mineral surface and implication to oligin of life under seafloor hydrothermal conditions

    NASA Astrophysics Data System (ADS)

    Fuchida, S.; Masuda, H.

    2012-12-01

    The sediments at hydrothermal and/or various parts of the crust has been believed to be good environments to proceed the chemical evolution of life precursor, since minerals promoted oligomerization of amino acids, sugars and lipids on the primitive earth. In this study, the thermal behaviors of glycine (Gly), the simplest amino acid, adsorbed on montmorillonite was observed to evaluate the role of clay minerals and water on the oligomerization under thermal condition of sediments. Gly was adsorbed on montmorillonite was heated at 150 degree C for 3-288 hrs under dry and wet condition. In the latter case, 10 - 60% water was added in the system. The amount of Gly monomer remaining in the montmorillonite exponentially decreased with time; 46% Gly remained in the montmorillonite under dry condition and 74% under wet condition after 288 hrs. The Gly monomer was more stable under hydrothermal condition than dry thermal condtion. FT-IR analysis suggested that the Gly was intercalated in the montmorillonite via hydrogen bond, which is likely to promote to stabilize Gly, between amino group of the Gly and silanol group of the montmorillonite. On the contrast, the yields of peptides were low on motmorillonite after heated under the wet condition: the amounts of glycilglycine (Gly-Gly) and diketopiperazine (DKP) are 0.8% and 0.9%, respectively. The amounts of DKP and GlyGly are 12.9% and 4.8% after heated under the dry condtion. Excessive water would promote to hydrolyze synthesized peptides. New band at 1671cm-1 by FT-IR implies that DKP was condensed on the montmorillonite. DKP was not formed without montmorillonite under the dry condition, although peptide formation is theoretically favorable. Water molecules including in the montmorillonite would act as proton transfer to promote the peptide formation. The peptide formation would be more proceeded under a little wet condition than completely dry condition. Results of this study suggested that deep sediments, where dehydration easily occurs, is more appropriate condition to form and condense oligomer of amino acids than the seafloor surface. Moreover, clay minerals, as catalyst of peptide formation, must be an essential factors to proceed the chemical evolution of precursor life on the primitive earth.

  1. Biological effects of minerals

    SciTech Connect

    Guthrie, G.D. Jr.

    1991-09-01

    In general, clay materials exhibit a range of biological activities, from apparently inactive or slightly active, such as hematite, to highly fibrogenic and carcinogenic, such as fibrous brucite (nemalite). The zeolites also exhibit such as range, with some mordenite being slightly active and erionite being highly active; however, erionite is the only zeolite that has been studied extensively. The diversity of mineral species holds great potential for probing these mechanisms, especially when mineralogical data are integrated with biological data. Unfortunately, many of the studies reporting data on the biological effects of clays and zeolites fail to report detailed mineralogical information; hence, it is difficult at present to interpret the biological activities of minerals in terms of their physical and chemical properties. Important mineralogical data that are only rarely considered in biological research include exact mineralogy of the specimen (i.e., identification and abundance of contaminants), physical and chemical properties of minerals, and surface properties of minerals. 141 refs., 1 fig., 8 tabs.

  2. Reduction and long-term immobilization of technetium by Fe(II) associated with clay mineral nontronite

    SciTech Connect

    Jaisi, Deb P.; Dong, Hailiang; Plymale, Andrew E.; Fredrickson, Jim K.; Zachara, John M.; Heald, S.; Liu, Chongxuan

    2009-06-20

    99Tc is formed mostly during nuclear reactions and is released into the environment during weapons testing and inadvertent waste disposal. The long half-life, high environmental mobility (as Tc(VII)O4-) and its possible uptake into the food chain cause 99Tc to be a significant environmental contaminant. In this study, we evaluated the role of Fe(II) in biologically reduced clay mineral, nontronite (NAu-2), in reducing Tc(VII)O4- to poorly soluble Tc(IV) species as a function of pH and Fe(II) concentration. The rate of Tc(VII) reduction by Fe(II) in NAu-2 was higher at neutral pH (pH 7.0) than at acidic and basic pHs when Fe(II) concentration was low (< 1 mmol/g). The effect of pH, however, was insignificant at higher Fe(II) concentrations. The reduction of Tc(VII) by Fe(II) associated with NAu-2 was also studied in the presence of common subsurface oxidants including iron and manganese oxides, nitrate, and oxygen, to evaluate the effect of the oxidants on the enhancement and inhibition of Tc(VII) reduction, and reoxidation of Tc(IV). Addition of iron oxides (goethite and hematite) to the Tc(VII)-NAu-2 system, where Tc(VII) reduction was ongoing, enhanced reduction of Tc(VII), apparently as a result of re-distribution of reactive Fe(II) from NAu-2 to more reactive goethite/hematite surfaces. Addition of manganese oxides stopped further Tc(VII) reduction, and in case of K+-birnessite, it reoxidized previously reduced Tc(IV). Nitrate neither enhanced reduction of Tc(VII) nor promoted reoxidation of Tc(IV). Approximately 11% of Tc(IV) was oxidized by oxygen. The rate and extent of Tc(IV) reoxidation was found to strongly depend on the nature of the oxidants and concentration of Fe(II). When the same oxidants were added to aged Tc reduction products (mainly NAu-2 and TcO2•nH2O), the extent of Tc(IV) reoxidation decreased significantly relative to fresh Tc(IV) products. Increasing NAu-2 concentration also resulted in the decreased extent of Tc(IV) reoxidation. The results were attributed to the effect of NAu-2 aggregation that effectively retained Tc(IV) in the solid and decreased its vulnerability to reoxidation. Overall, our results implied that bioreduced clay minerals could play an important role in reducing Tc(VII) and in maintaining the long-term stability of reduced Tc(IV).

  3. Deglacial Record in the Illinois River Valley Explains Asynchronous Phases of Meltwater Pulses and Clay Mineral Excursions in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Wang, H.

    2014-12-01

    One prominent event of the Bølling/Allerød (B/A) interstadial was the large meltwater release to global oceans. The Laurentide Ice Sheet (LIS) is usually considered the main source. But, the large LIS meltwater discharge conflicts with the marine record showing an active North Atlantic meridional overturning circulation (AMOC) during the B/A interval. Continuous dune-lacustrine successions in the Illinois River Valley (IRV) have shown complete records of the last deglacial chronozones. Their grain-size distributions and accurate B/A age 14C dates of plant fossils from 15 m deep lacustrine sediment in the IRV suggest that most of the IRV and parts of the adjacent upland were inundated by water. The inundation was caused by a sediment dam interpreted to have been constructed and followed by a breach at the confluence of the Mississippi and Illinois Rivers during the B/A interval due to sediment mobilization by the large meltwater release. The grain size distributions correlate with meltwater pulses and mineralogical excursions in sediments from the Gulf of Mexico (GOM) very well. The blockage and release of illite and chlorite rich fine-grained sediments from the Lake Michigan basin changed the relative abundance of clay minerals and thus the ratio of smectite/(illite + chlorite) in the sediment of the GOM. This finding explains why the meltwater episodes from the LIS and the associated detrital discharges are not synchronous in the sediments in the GOM. The finding also ties meltwater pulses and associated detrital discharges in the GOM closely to the LIS discharges via the Mississippi River Valley on chronozonal scales. Three arguments can be made from this result: 1) unaffected AMOC during B/A interval resulted potentially from the hyperpycnal inflow into the GOM floor; 2) limited volume of the meltwater discharge did not significantly influence the AMOC; and 3) the freshwater input into the GOM from the LIS at this particular location did not significantly influence the AMOC.

  4. Minerals

    MedlinePLUS

    Minerals are important for your body to stay healthy. Your body uses minerals for many different jobs, including building bones, making ... regulating your heartbeat. There are two kinds of minerals: macrominerals and trace minerals. Macrominerals are minerals your ...

  5. Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay

    NASA Astrophysics Data System (ADS)

    Charlet, L.; Scheinost, A. C.; Tournassat, C.; Greneche, J. M.; Géhin, A.; Fernández-Martínez, A.; Coudert, S.; Tisserand, D.; Brendle, J.

    2007-12-01

    The mobility and availability of the toxic metalloid selenium in the environment are largely controlled by sorption and redox reactions, which may proceed at temporal scales similar to that of subsurface water movement under saturated or unsaturated conditions. Since such waters are often anaerobic and rich in Fe 2+, we investigated the long-term (?1 month) kinetics of selenite (Se(IV)O3-) sorption to montmorillonite in the presence of Fe 2+ under anoxic conditions. A synthetic montmorillonite was used to eliminate the influence of structural Fe. In the absence of aqueous Fe 2+, selenite was sorbed as outer-sphere sorption complex, covering only part of the positive edge sites, as verified by a structure-based MUSIC model and Se K-edge XAS (X-ray absorption spectroscopy). When selenite was added to montmorillonite previously equilibrated with Fe 2+ solution however, slow reduction of Se and formation of a solid phase was observed with Se K-edge XANES (X-ray absorption near-edge spectroscopy) and EXAFS (extended X-ray absorption fine-structure) spectroscopy. Iterative transformation factor analysis of XANES and EXAFS spectra suggested that only one Se reaction product formed, which was identified as nano-particulate Se(0). Even after one month, only 75% of the initially sorbed Se(IV) was reduced to this solid species. Mössbauer spectrometry revealed that before and after addition and reduction of Se, 5% of total sorbed Fe occurred as Fe(III) species on edge sites of montmorillonite (?2 mmol kg -1). The only change observed after addition of Se was the formation of a new Fe(II) species (15%) attributed to the formation of an outer-sphere Fe(II)-Se sorption complex. The combined Mössbauer and XAS results hence clearly suggest that the Se and Fe redox reactions are not directly coupled. Based on the results of a companion paper, we hypothesize that the electrons produced in the absence of Se by oxidation of sorbed Fe(II) are stored, for example by formation of surface H 2 species, and are then available for the later Se(IV) reduction. The slow reaction rate indicates a diffusion controlled process. Homogeneous precipitation of an iron selenite was thermodynamically predicted and experimentally observed only in the absence of clay. Interestingly, half of Fe was oxidized in this precipitate (Mössbauer). Since DFT calculations predicted the oxidation of Fe at the water-FeSe solid interface only and not in the bulk phase, we derived an average particle size of this precipitate which does not exceed 2 nm. A comparison with the Mössbauer and XAS spectra of the clay samples demonstrates that such homogenous precipitation can be excluded as a mechanism for the observed slow Se reduction, emphasizing the role of abiotic, heterogeneous precipitation and reduction for the removal of Se from subsurface waters.

  6. Antibiotic eluting clay mineral (Laponite®) for wound healing application: an in vitro study.

    PubMed

    Ghadiri, M; Chrzanowski, W; Rohanizadeh, R

    2014-11-01

    Different materials in form of sponge, hydrogel and film have been developed and formulated for treating and dressing burn wounds. In this study, the potential of Laponite, a gel forming clay, in combination with an antimicrobial agent (mafenide), as a wound dressing material was tested in vitro. Laponite/mafenide (Lap/Maf) hydrogel was formulated in three different ratios of Lap/Maf 1:1, 1:2, 1:3. Laponite/mafenide/alginate (Lap/Maf/Alg) film was also formulated by combining Lap/Maf gel (1:1) with alginate. Intercalation rate of mafenide into the layers of Laponite nanoparticles and physico-chemical properties, including wound dressing characteristics of materials were studied using various analytical methods. Furthermore, the degradation of materials and the release profile of mafenide were investigated in simulated wound exudates fluid and antibacterial effectiveness of the eluted mafenide was tested on a range of bacterial species. The cytotoxicity of materials was also evaluated in skin fibroblast culture. The results showed that mafenide molecules were intercalated between the nano-sized layers of Laponite. The eluted mafenide showed active antibacterial effects against all three tested bacteria. All intercalated mafenide released from Lap/Maf 1:1 and 1:2 gel formulations and nearly 80% release from 1:3 formulation during test period. No significant difference was observed in release profile of mafenide between Lap/Maf/Alg film and Lap/Maf formulations. Wound dressing tests on Lap/Maf/Alg film showed it is a breathable dressing and has capacity to absorb wound exudates. The study showed that prepared Lap/Maf composite has the potential to be used as an antibiotic eluting gel or film for wound healing application. Additionally, Laponite has shown benefits in wound healing processes by releasing Mg(2+) ions and thereby reducing the cytotoxic effect of mafenide on fibroblast cells. PMID:25027303

  7. On the origin of mixed-layered clay minerals from the San Andreas Fault at 2.5–3 km vertical depth (SAFOD drillhole at Parkfield, California)

    Microsoft Academic Search

    A. M. Schleicher; L. N. Warr; B. A. van der Pluijm

    2009-01-01

    A detailed mineralogical study is presented of the matrix of mudrocks sampled from spot coring at three key locations along\\u000a the San Andreas Fault Observatory at depth (SAFOD) drill hole. The characteristics of authigenic illite–smectite (I–S) and\\u000a chlorite–smectite (C–S) mixed-layer mineral clays indicate a deep diagenetic origin. A randomly ordered I–S mineral with ca.\\u000a 20–25% smectite layers is one of

  8. CLAYFORM: a FORTRAN 77 computer program apportioning the constituents in the chemical analysis of a clay or other silicate mineral into a structural formula

    USGS Publications Warehouse

    Bodine, M.W., Jr.

    1987-01-01

    The FORTRAN 77 computer program CLAYFORM apportions the constituents of a conventional chemical analysis of a silicate mineral into a user-selected structure formula. If requested, such as for a clay mineral or other phyllosilicate, the program distributes the structural formula components into appropriate default or user-specified structural sites (tetrahedral, octahedral, interlayer, hydroxyl, and molecular water sites), and for phyllosilicates calculates the layer (tetrahedral, octahedral, and interlayer) charge distribution. The program also creates data files of entered analyses for subsequent reuse. ?? 1987.

  9. Insights into the Mechanism of Fe(II) Adsorption and Oxidation at Fe-Clay Mineral Surfaces from First-Principles Calculations

    SciTech Connect

    Alexandrov, Vitali Y.; Rosso, Kevin M.

    2013-10-02

    Interfacial reactivity of redox-active iron-bearing mineral surfaces plays a crucial role in many environmental processes including biogeochemical cycling of various elements and contaminants. Herein, we apply density-functional-theory (DFT) calculations to provide atomistic insights into the heterogeneous reaction between aqueous Fe(II) and the Fe-bearing clay mineral nontronite Fe2Si4O10(OH)2 by studying its adsorption mechanism and interfacial Fe(II)-Fe(III) electron transfer (ET) at edge and basal surfaces. We find that edge-bound Fe(II) adsorption complexes at different surface sites (ferrinol, silanol and mixed) may coexist on both (010) and (110) edge facets, with complexes at ferrinol FeO(H) sites being the most energetically favorable and coupled to proton transfer. Calculation of the ET activation energy suggests that interfacial ET into dioctahedral Fe(III) sheets is probable at the clay edges and occurs predominantly but not exclusively through the complexes adsorbed at ferrinol sites and might also involve mixed sites. No clear evidence is found for complexes on basal surface that are compatible with ET through the basal sheet despite this experimentally hypothesized ET interface. This study suggests a strong pH-dependence of Fe(II) surface complexation at basal versus edge facets and highlights the importance of the protonation state of bridging ligands and proton coupled electron transfer to facilitate ET into Fe-rich clay minerals.

  10. Synergy between polyaniline and OMt clay mineral in Langmuir-Blodgett films for the simultaneous detection of traces of metal ions.

    PubMed

    de Barros, Anerise; Ferreira, Mariselma; Constantino, Carlos José Leopoldo; Bortoleto, José Roberto Ribeiro; Ferreira, Marystela

    2015-04-01

    We report on Langmuir-Blodgett (LB) films made with emeraldine salt polyaniline (PAni-ES) and organophilic montmorillonite clay mineral (OMt), where synergy between the components was reached to yield an enhanced performance in detecting trace levels of cadmium (Cd(2+)), lead (Pb(2+)) and copper (Cu(2+)). Detection was carried out using square wave anodic stripping (SWAS) voltammetry with indium tin oxide (ITO) electrodes modified with LB films of PAni-ES/OMt nanocomposite, whose data were compared to those obtained with electrodes coated with neat PAni-ES and neat OMt LB films. The enhanced performance in the nanocomposite may be attributed to the stabilizing and ordering effect promoted by OMt in PAni-ES Langmuir films, which then led to more homogeneous LB films. According to X-ray diffraction data, the stacking of OMt layers was preserved in the LB films and therefore the PAni-ES chains did not cause clay mineral exfoliation. Instead, OMt affected the polaronic state of PAni-ES as indicated in UV-vis, Raman and FTIR spectra, also consistent with the changes observed for the Langmuir films. Taken together these results do indicate that semiconducting polymers and clay minerals may be combined for enhancing the electrical properties of nanostructures for sensing and related applications. PMID:25761908

  11. Adsorption of dissolved aluminum on sapphire-c and kaolinite: implications for points of zero charge of clay minerals

    PubMed Central

    2014-01-01

    We have studied the impact of dissolved aluminum on interfacial properties of two aluminum bearing minerals, corundum and kaolinite. The effect of intentionally adding dissolved aluminum on electrokinetic potential of basal plane surfaces of sapphire was studied by streaming potential measurements as a function of pH and was complemented by a second harmonic generation (SHG) study at pH 6. The electrokinetic data show a similar trend as the SHG data, suggesting that the SHG electric field correlates to zeta-potential. A comparable study was carried out on kaolinite particles. In this case electrophoretic mobility was measured as a function of pH. In both systems the addition of dissolved aluminum caused significant changes in the charging behavior. The isoelectric point consistently shifted to higher pH values, the extent of the shift depending on the amount of aluminum present or added. The experimental results imply that published isoelectric points of clay minerals may have been affected by this phenomenon. The presence of dissolved aluminum in experimental studies may be caused by particular pre-treatment methods (such as washing in acids and subsequent adsorption of dissolved aluminum) or even simply by starting a series of measurements from extreme pH (causing dissolution), and subsequently varying the pH in the very same batch. This results in interactions of dissolved aluminum with the target surface. A possible interpretation of the experimental results could be that at low aluminum concentrations adatoms of aluminum (we will refer to adsorbed mineral constituents as adatoms) can form at the sapphire basal plane, which can be rather easily removed. Simultaneously, once the surface has been exposed to sufficiently high aluminum concentration, a visible change of the surface is seen by AFM which is attributed to a surface precipitate that cannot be removed under the conditions employed in the current study. In conclusion, whenever pre-treatment or the starting point of an experiment favor the dissolution of aluminum, dissolved Al may remain in the experimental system and interact with the target surfaces. The systems are then no longer pristine and points of zero charge or sorption data are those of aluminum-bearing systems. PMID:25045321

  12. The Effects of Microbial Fe(III) reduction on Clay Sediment Flocculation and Mineral Transformation

    NASA Astrophysics Data System (ADS)

    Kim, J.; Furukawa, Y.; Newell, S.; Daulton, T.; Dong, H.

    2003-12-01

    This study was undertaken to investigate physicochemical properties of smectite associated with microbial reduction of structural Fe(III). Iron reducing bacterium, Shewanella oneidensis were inoculated with formate as the electron donor and smectite as the sole electron acceptor for the intervals of 3, 12, 24, and 48 hours in anaerobic chamber. The extent of Fe(III) reduction was observed to reach up to 9%. The control, containing microwave radiation heat-killed bacterial cells and M1 media plus formate, was prepared from the same smectite sample. Settling experiments were performed in anaerobic chamber for 1) the bioreduced nontronite samples which contain viable cells and biopolymers secreted by bacteria, with variable incubation time points, and 2) abiotic nonreduced controls having dead cells (no biopolymers). Furthermore, the separate set of incubation was prepared in aerobic condition where the microbial Fe-respiration does not prevail, but viable bacteria produced the biopolymers, and then suspended in a settling column in aerobic condition. Compared with abiotic nonreduced control, Micromeritics Sedigraph measured 2.3-m increase of mean aggregate size and a 30-times faster average settling velocity in the bioreduced nontronite suspensions. In addition, the aerobically inoculated nontronite (no Fe-respiration) shows a similar aggregate size distribution to that of an abiotic nonreduced control. Significant changes in physical properties of smectite induced by microbial Fe(III) reduction were directly observed using Environmental Cell Transmission Electron Microscope (EC-TEM). Particularly, neoformation of minerals in bioreduced smectite sample indicate that environmental factor such as bacterial activity should be considered as a geological variable for the mineral transformation studies. Neoformed Illite phase was identified in bioreduced smectite sample that challenge the conventional concept of smectite-to-illite transformation with far-reaching implications. In floc architecture, several domains of smectite packets are glued by biopolymers secreted by bacteria, and the aspect ratio (thickness/length) of individual smectite particle increases from 0.11 to 0.18. We suggest that surface chemistry changes (more negatively charged on smectite surface) induced by microbial Fe(III) reduction more likely to promote the flocculation by absorbing the cations which bridge the smectite particles and the biopolymers resulting in the increase of mean aggregate size.

  13. Stable Isotope Systematics of Abiotic Nitrite Reduction Coupled with Anaerobic Iron Oxidation: The Role of Reduced Clays and Fe-bearing Minerals

    NASA Astrophysics Data System (ADS)

    Grabb, K. C.; Buchwald, C.; Hansel, C. M.; Wankel, S. D.

    2014-12-01

    Under anaerobic conditions, it is widely assumed that nitrate (NO3-) and nitrite (NO2-) reduction is primarily the result of microbial respiration. However, it has also been shown that abiotic reduction of nitrate and nitrite by reduced iron (Fe(II)), whether mineral-bound or surface-associated, may also occur under certain environmentally relevant conditions. With a range of experimental conditions, we investigated the nitrogen and oxygen stable isotope systematics of abiotic nitrite reduction by Fe(II) in an effort to characterize biotic and abiotic processes in the environment. While homogenous reactions between NO2- and Fe(II) in artificial seawater showed little reduction, heterogeneous reactions involving Fe-containing minerals showed considerable nitrite loss. Specifically, rapid nitrite reduction was observed in experiments that included reduced clays (illite, Na-montmorillonite, and nontronite) and those that exhibited iron oxide formation (ferrihydrite, magnetite and/or green rust). While these iron oxides and clay minerals offer both a source of reduced iron in the mineral matrix as well as a surface for Fe(II) activation, control experiments with corundum as a non-Fe containing mineral surface showed little NO2- loss, implicating a more dominant role of structural Fe in the clays during nitrite reduction. The isotope effects for 15N and 18O (15? and 18?) ranged from 5 to 14‰ for 15? and 5 to 17‰ for 18? and were typically coupled such that 15? ~ 18?. Reactions below pH 7 were slower and the 18? was affected by oxygen atom exchange with water. Although little data exist for comparison with the dual isotopes of microbial NO2- reduction, these data serve as a benchmark for evaluating the role of abiotic processes in N reduction, particularly in sediment systems low in organic carbon and high in iron.

  14. Characterization of clay from northern of Morocco for their industrial application

    NASA Astrophysics Data System (ADS)

    El Ouahabi, Meriam; Fagel, Nathalie

    2010-05-01

    Clays are a natural resource used for millennia. Currently applications such as industrial minerals are diversified. In this context, our goal is to estimate the potential of the many clay deposits in northern of Morocco. The choice of this region is justified by the particular abundance of clay deposits used to manufacture building materials (brick, ceramic and refractories) and pottery. This study focuses on the mineralogical, chemical and geotechnical characterization tests carried out on Tangier-Tetouan and Meknes clays from northern of Morocco. The suitability of raw clay material from those regions in order to produce ceramic and brick has not been tested yet. The results revealed that the studied samples are diversified, kaolinite and illite (Tetouan clay) and kaolinite and illite and smectite and vermiculite (Tangier and Meknes clay) based materials. There were no major differences in grain-size distribution, whereas Meknes clay was more plastic than Tetouan-Tangier clay. The cation exchange capacity show that Meknes and Tangier clay were more important than Tetouan clay. Specific surface area and thermal analaysis complete this caracterization. It was found that almost all technological properties of the Meknes clay deposit are led to the manufacture of ceramic floor tile, and Tetouan-Tangier clay provide opportunities to making brick and ceramic floor. The Tetouan-Tangier and Meknes clay are a potential ceramic raw material for growing Morrocan ceramic tile and brick industries.

  15. Characterization of the Waukesha Illite: A mixed-polytype illite in the Clay Mineral Society repository

    USGS Publications Warehouse

    Grathoff, Georg H.; Moore, D.M.

    2002-01-01

    The Waukesha Illite is an excellent example of the illites found in argillaceous rocks, typical for Paleozoic shales that have undergone significant burial diagenesis during their geologic history. It consists of a mixture of detrital 2M1, interpreted to be a residuum of karstification within Silurian carbonates, and diagenetic 1M and 1Md illite. The chemistry and the age of the illite polytypes are different. Extrapolating to 100%, the 1M and 1Md polytypes have an apparent diagenetic age between 295 and 325 Ma. The chemistry of the 1M polytype could not be determined because of its low abundance. The approximate chemical composition of the 1Md polytype is 0.67 K, 3.6 Si, and 1.9 Al per half unit cell. The 2M1 polytype has an apparent detrital age between 440 and 520 Ma, and an approximate chemical composition per half unit cell of 0.78 K, 3.4 Si, and 2.1 Al, all within our margin of error. X-ray diffraction (XRD) results of both random powder and oriented preparations both indicate that the Waukesha Illite consists of a mixture of illites. The XRD patterns of the random powder preparation indicate it is a physical mixture of three different illite polytypes. This result was confirmed using 3 different methods: (1) by measuring illite polytype-specific reflections; (2) by mixing illite polytype reference samples; and (3) by mixing WILDFIRE calculated XRD patterns. Decomposition of the illite 001 XRD peak from oriented preparations also indicates mixtures of illites. However, the proportions of the three illitic components derived from the oriented 001 peak decomposition differ from those results derived from the analysis of the random powder data. Therefore, the shape of the 001 reflection of the Waukesha Illite cannot be explained by mixing the three different illite polytypes.

  16. How clays weaken faults.

    NASA Astrophysics Data System (ADS)

    van der Pluijm, Ben A.; Schleicher, Anja M.; Warr, Laurence N.

    2010-05-01

    The weakness of upper crustal faults has been variably attributed to (i) low values of normal stress, (ii) elevated pore-fluid pressure, and (iii) low frictional strength. Direct observations on natural faults rocks provide new evidence for the role of frictional properties on fault strength, as illustrated by our recent work on samples from the San Andreas Fault Observatory at Depth (SAFOD) drillhole at Parkfield, California. Mudrock samples from fault zones at ~3066 m and ~3296 m measured depth show variably spaced and interconnected networks of displacement surfaces that consist of host rock particles that are abundantly coated by polished films with occasional striations. Transmission electron microscopy and X-ray diffraction study of the surfaces reveal the occurrence of neocrystallized thin-film clay coatings containing illite-smectite (I-S) and chlorite-smectite (C-S) phases. X-ray texture goniometry shows that the crystallographic fabric of these faults rocks is characteristically low, in spite of an abundance of clay phases. 40Ar/39Ar dating of the illitic mix-layered coatings demonstrate recent crystallization and reveal the initiation of an "older" fault strand (~8 Ma) at 3066 m measured depth, and a "younger" fault strand (~4 Ma) at 3296 m measured depth. Today, the younger strand is the site of active creep behavior, reflecting continued activation of these clay-weakened zones. We propose that the majority of slow fault creep is controlled by the high density of thin (< 100nm thick) nano-coatings on fracture surfaces, which become sufficiently smectite-rich and interconnected at low angles to allow slip with minimal breakage of stronger matrix clasts. Displacements are accommodated by localized frictional slip along coated particle surfaces and hydrated smectitic phases, in combination with intracrystalline deformation of the clay lattice, associated with extensive mineral dissolution, mass transfer and continued growth of expandable layers. The localized concentration of smectite in both I-S and C-S minerals, which probably extends to greater depths (<10 km) is responsible for fault weakening, with cataclasis and fluid infiltration creating nucleation sites for neomineralization on displacement surfaces during continued faulting. The role of newly grown, ultrathin, hydrous clay coatings on displacement surfaces in the San Andreas Fault contrasts with previously proposed scenarios of reworked talc/serpentine phases as an explanation for weak faults and creep behavior at these depths.

  17. Clay mineral assemblages of terrestrial records (Xining Basin, China) during the Eocene-Oligocene climate Transition (EOT) and its environmental implications

    NASA Astrophysics Data System (ADS)

    Zhang, C.; Guo, Z.

    2013-12-01

    The Eocene-Oligocene Transition (EOT) between ~34.0 and 33.5 million years ago, where global climate cooled from 'greenhouse' to 'icehouse' at ~33.5 Ma ago, is one of the great events during Cenozoic climate deterioration. In contrast to the marine records of the EOT, significantly less research has focused on the continental climate change during this time, particularly in inner Asia. We present a comprehensive study of the upper Eocene to lower Oligocene succession with regular alternations of laterally continuous gypsum/gypsiferous layers and red mudstone beds in Tashan section of Xining Basin, which is located at the northeastern margin of the Tibetan Plateau. Clay minerals, which were extracted from this succession, were analyzed qualitatively and semi-quantitatively by using X-ray differaction (XRD). Base on detailed magnetostratigraphic time control, clay mineral compositions of this succession (33.1-35.5 Ma) are compared with open ocean marine records and Northern Hemisphere continental records to understand the process and characteristics of Asian climate change before, during and after EOT. Our results indicate that illite is the dominant clay mineral with less chlorite and variable smectite. Multi-parameter evidence suggests that the source areas of detrital inputs in Tashan have not changed and climate is the main control for the composition of the clay fraction. The characteristics of clay mineral concentrations suggest warm and humid fluctuations with cold and dry conditions and intense of seasonality during ~35.5-34.0 Ma in inner Asian. This changed to cold and dry condition at ~34 Ma and remained so from ~34-33.1 Ma. The comparisons between continental and marine records indicate that the climate changes experienced in the Xining basin region are more consistent with Northern Hemisphere rather than open oceans records. This indicates that paleoclimate changes for inner Asian before, during and after EOT was not controlled by Antarctic ice growth, but may be due to atmospheric cooling linked to the existence and expansion of Northern Hemisphere glaciation.

  18. Evidence of multi-stage faulting by clay mineral analysis: Example in a normal fault zone affecting arkosic sandstones (Annot sandstones)

    NASA Astrophysics Data System (ADS)

    Buatier, Martine D.; Cavailhes, Thibault; Charpentier, Delphine; Lerat, Jérémy; Sizun, Jean Pierre; Labaume, Pierre; Gout, Claude

    2015-06-01

    Fault affecting silicoclastic sediments are commonly enriched in clay minerals. Clays are sensitive to fluid-rock interactions and deformation mechanisms; in this paper, they are used as proxy for fault activity and behavior. The present study focuses on clay mineral assemblages from the Point Vert normal fault zone located in the Annot sandstones, a Priabonian-Rupelian turbidite succession of the Alpine foredeep in SE France. In this area, the Annot sandstones were buried around 6-8 km below the front of Alpine nappes soon after their deposition and exhumed during the middle-late Miocene. The fault affects arkosic sandstone beds alternating with pelitic layers, and displays throw of about thirty meters. The fault core zone comprises intensely foliated sandstones bounding a corridor of gouge about 20 cm thick. The foliated sandstones display clay concentration along S-C structures characterized by dissolution of K-feldspar and their replacement by mica, associated with quartz pressure solution, intense microfracturation and quartz vein precipitation. The gouge is formed by a clayey matrix containing fragments of foliated sandstones and pelites. However, a detailed petrographical investigation suggests complex polyphase deformation processes. Optical and SEM observations show that the clay minerals fraction of all studied rocks (pelites and sandstones from the damage and core zones of the fault) is dominated by white micas and chlorite. These minerals have two different origins: detrital and newly-formed. Detrital micas are identified by their larger shape and their chemical composition with a lower Fe-Mg content than the newly-formed white micas. In the foliated sandstones, newly-formed white micas are concentrated along S-C structures or replace K-feldspar. Both types of newly formed micas display the same chemical composition confirmed microstructural observations suggesting that they formed in the same conditions. They have the following structural formulas: Na0.05 K0.86 (Al 1.77 Fe0.08 Mg0.15) (Si3.22 Al0.78) O10 (OH)2. They are enriched in Fe and Mg compared to the detrital micas. Newly-formed chlorites are associated with micas along the shear planes. According to microprobe analyses, they present the following structural formula: (Al1,48 Fe2,50 Mg1,84) (Si2,82 Al1,18) O10 (OH)8. All these data suggest that these clay minerals are synkinematic and registered the fault activity. In the gouge samples, illite and chlorite are the major clay minerals; smectite is locally present in some samples. In the foliated sandstones, Kubler Index (KI) ((001) XRD peak width at half height) data and thermodynamic calculations from synkinematic chlorite chemistry suggest that the main fault deformation occurred under temperatures around 220 °C (diagenesis to anchizone boundary). KI measured on pelites and sandstones from the hanging and footwall, display similar values coherent with the maximal burial temperature of the Annot sandstones in this area. The gouge samples have a higher KI index, which could be explained by a reactivation of the fault at lower temperatures during the exhumation of the Annot sandstones formation.

  19. Distribution of clay minerals in surface sediments from the eastern Barents and south-western Kara seas

    Microsoft Academic Search

    D. Nürnberg; M. A. Levitan; J. A. Pavlidis; E. S. Shelekhova

    1995-01-01

    Surface samples from the eastern Barents and south-western Kara seas have been analysed for clay mineralogy. Transport paths, the role of regional sources and local bedrock outcrops and the influence of hydrodynamic and glacigenous processes for clay distribution on the shelves are discussed in relation to central Arctic Ocean deep sea and sea ice sediments. Franz Josef Land and Novaya

  20. Stepwise effects of the BCR sequential chemical extraction procedure on dissolution and metal release from common ferromagnesian clay minerals: a combined solution chemistry and X-ray powder diffraction study.

    PubMed

    Ryan, P C; Hillier, S; Wall, A J

    2008-12-15

    Sequential extraction procedures (SEPs) are commonly used to determine speciation of trace metals in soils and sediments. However, the non-selectivity of reagents for targeted phases has remained a lingering concern. Furthermore, potentially reactive phases such as phyllosilicate clay minerals often contain trace metals in structural sites, and their reactivity has not been quantified. Accordingly, the objective of this study is to analyze the behavior of trace metal-bearing clay minerals exposed to the revised BCR 3-step plus aqua regia SEP. Mineral quantification based on stoichiometric analysis and quantitative powder X-ray diffraction (XRD) documents progressive dissolution of chlorite (CCa-2 ripidolite) and two varieties of smectite (SapCa-2 saponite and SWa-1 nontronite) during steps 1-3 of the BCR procedure. In total, 8 (+/-1) % of ripidolite, 19 (+/-1) % of saponite, and 19 (+/-3) % of nontronite (% mineral mass) dissolved during extractions assumed by many researchers to release trace metals from exchange sites, carbonates, hydroxides, sulfides and organic matter. For all three reference clays, release of Ni into solution is correlated with clay dissolution. Hydrolysis of relatively weak Mg-O bonds (362 kJ/mol) during all stages, reduction of Fe(III) during hydroxylamine hydrochloride extraction and oxidation of Fe(II) during hydrogen peroxide extraction are the main reasons for clay mineral dissolution. These findings underscore the need for precise mineral quantification when using SEPs to understand the origin/partitioning of trace metals with solid phases. PMID:18951614

  1. Laboratory experiments on Mars-relevant clay and phosphate minerals yield insights into the aqueous history and potential for habitability on Mars.

    NASA Astrophysics Data System (ADS)

    Hausrath, E.; Adcock, C. T.; Gainey, S.; Hurowitz, J. A.; Tu, V.

    2012-12-01

    Data from Mars landers and orbiters increasingly indicate the occurrence of aqueous geochemical processes, suggesting the presence of environments that may be habitable. These environments, however, differ from terrestrial environments in significant ways. Laboratory experiments can therefore be vital in providing further insight into environmental conditions on Mars, and the implications for habitability. Here we report the results of experiments designed to interpret observations of Mars from landers, orbiters and martian meteorites. Dissolution rates of the Mars-relevant phosphate minerals whitlockite, merrillite, and chlorapatite, as well as amorphous Al- and Fe-phosphates, suggest rapid dissolution of these phases. Phosphate release on Mars may therefore have been greater than on Earth, with important implications for habitability. Measured dissolution rates of nontronite when compared to montmorillonite dissolution rates from the literature suggest that preferential dissolution of nontronite may be able to account for enrichments of montmorillonite and kaolinite in profiles at Mawrth Vallis. Synthesis experiments of clay minerals under oxidizing and reducing conditions may help interpret transitions in clay mineral chemistry as a possible paleoredox indicator.

  2. Minerals

    NSDL National Science Digital Library

    2007-12-12

    This site provides an in-depth look at mineral properties and identification. An alphabetical listing of common minerals allows the user to see a picture and view physical properties of the particular mineral. Properties of minerals are explained, including cleavage, hardness, crystal form, and luster. There are also downloadable labs for crystal models and mineral data sheets. Dichotomous and hardness keys are given for easier mineral identification.

  3. EXTENDING THE PREDICTION OF THE THERMODYNAMIC PROPERTIES OF CLAY

    E-print Network

    Paris-Sud XI, Université de

    EXTENDING THE PREDICTION OF THE THERMODYNAMIC PROPERTIES OF CLAY MINERALS TO THE TRAPPING OF TRACE The thermodynamic properties of clay minerals, which control the stability of these minerals in solution, are still are parameterised using a given set of minerals. For clay minerals, the latter are mainly composed by Si, Al, Fe

  4. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2004-01-01

    Part of the 2003 industrial minerals review. The legislation, production, and consumption of common clay and shale are discussed. The average prices of the material and outlook for the market are provided.

  5. Intercalated clay catalysts

    Microsoft Academic Search

    T. J. Pinnavaia

    1983-01-01

    Recent advances in the intercalation of metal complex cations in smectite clay minerals are leading to the development of new classes of selective heterogeneous catalysts. The selectivity of both metal-catalyzed and proton-catalyzed chemical conversions in clay intercalates can often be regulated by controlling surface chemical equilibria, interlamellar swelling, or reactant pair proximity in the interlayer regions. Also, the intercalation of

  6. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2003-01-01

    Part of the 2002 industrial minerals review. The production, consumption, and price of shale and common clay in the U.S. during 2002 are discussed. The impact of EPA regulations on brick and structural clay product manufacturers is also outlined.

  7. Clay minerals in sediments of Portuguese reservoirs and their significance as weathering products from over-eroded soils: a comparative study of the Maranhão, Monte Novo and Divor Reservoirs (South Portugal)

    NASA Astrophysics Data System (ADS)

    Fonseca, Rita M. F.; Barriga, Fernando J. A. S.; Conceição, Patrícia I. S. T.

    2010-12-01

    The Southern region of Portugal is subjected to several forms of over-erosion. Most leached products, mainly composed of fine particles containing nutrients, metals or pesticides, are easily transported by river flows. When these are hindered by a physical barrier such as a dam, the particulate load accumulates on the bottom of the reservoirs, often leading to a pronounced decrease of water quality. Bottom sediments from three reservoirs were subjected to grain-size analysis and a study of clay minerals by X-ray diffraction. Most sediments contain a diverse set of clay minerals, mostly illites, smectites, chlorites and kaolinites. The nature of the clay minerals reflects the nature of the parent rocks. During the cycles of transport and temporary deposition, they may undergo significant chemical and physical transformations, which lead to an increase of expandable properties and therefore, to a higher cationic exchange capacity, determining its important role as vehicles of environmental pollutants.

  8. Mineral catalysis of the formation of the phosphodiester bond in aqueous solution - The possible role of montmorillonite clays

    NASA Technical Reports Server (NTRS)

    Ferris, James P.; Ertem, Gozen; KAMALUDDIN; Agarwal, Vipin; Hua, Lu Lin

    1989-01-01

    The possible role of montmorillonite clays in the spontaneous formation on the primitive earth of the phosphodiester bond in the presence of water was investigated in experiments measuring the binding of various nucleosides and nucleotides with Na(+)-montmorillonite 22A and the reactions of these compounds with a water-soluble carbodiimide. It was found that, at neutral pH, adenine derivatives bind stronger than the corresponding uracil derivatives, consistent with the protonation of the adenine by the acidic clay surface and a cationic binding of the protonated ring to the anionic clay surface. The reaction of the 5-prime-AMP with carbodiimide resulted in the formation of 2-prime,5-prime-pApA (18.9 percent), 3-prime,5-prime-pApA (11 percent), and AppA (4.8 percent). The yields of these oligomers obtained when poly(U) was used in place of the clay were 15.5 percent, 3.7 percent, and 14.9 percent AppA, respectively.

  9. On the interaction of triarylmethane dye crystal violet with LAPONITE® clay: using mineral nanoparticles to control the dye photophysics.

    PubMed

    Ley, C; Brendlé, J; Walter, A; Jacques, P; Ibrahim, A; Allonas, X

    2015-06-24

    The combination of an organic dye with clays leads to very interesting hybrid materials with original properties. It is found that LAPONITE® nanoparticles have an impact on the photophysical properties of the crystal violet dye inducing a kinetic stabilization of its excited emissive state, turning this nonemissive dye into a fluorescent compound. PMID:26028222

  10. Tracing the Southwest African climate development during the Miocene - changes in elemental distribution and clay mineral composition at DSDP Site 530A (southeastern Angola Basin)

    NASA Astrophysics Data System (ADS)

    Roters, B.

    2009-04-01

    During the middle and late Miocene the climatic system in Southwest Africa was reorganized leading to generally drier conditions as known from today. The reason for this was the cooling of the coastal-near ocean by the initialization of the Benguela Current. Thus the temperature difference between the continent and the sea increased and a system of seaward blowing winds developed. This lead to (1) the development of the Benguela Upwelling System in front of the Namibian coast and (2) it prevented the landward flow of humid air masses. The Mid-Miocene climate change in SW-Africa has been shown by data-sets from the Cape Basin and the Walvis Ridge (Kastanja et al., 2006; Westerhold et al., 2005; Diester-Haass et al., 2002; Roters & Henrich, in press). The DSDP Site 530A is situated in the SE corner of the Walvis Basin at the toe of the Walvis Ridge in a water depth of 4629 m. Today the distance to the coast is about 285 km. The idea is to trace the climatic development between 19 and 9 Myr with the help of (1) a clay mineral record and (2) the results of XRF-scanning of the core. The sediment is carbonate-depleted, which, inversely, enriches the terrigenous components. On the other hand mass accumulation rates are low and the age control of the sediments is difficult. XRF scanning was done on the archive cores at the MARUM, Bremen in a resolution of about 10 kyr, while the clay mineral contents were measured in the isolated clay fraction (< 2µm) on a XRD machine at the AWI, Bremerhaven in a 100 kyr resolution. By grain size analysis it was found that the content of clays (fraction < 2µm) of the sediments averages out to about 75%. The most prominent clays found in the samples are Illites. The remaining material is nearly completely composed of silt. The sediments could have been transported to site 530A by three different processes: (1) in the sediment load of the Kunene River and onwards by surface ocean currents, (2) with the dust load from the African continent and (3) by deeper ocean and bottom currents. In a previous grain size study of these sediments no indications for bottom currents were found. Material, which was suspicious to be transported by mass wasting events, has been excluded from this study. The grain size analysis showed a general coarsening of sediment after 11.5 Myr, when the Benguela Current system began to work. Also peaks of coarser material have been found before that general change. The scope of the here presented work is to trace these developments with chemical data and clay mineral contribution changes. First results show enrichment in Iron and Titanium contents after 11.5 Myr that is explained with higher dust input to the ocean. Literature: Diester-Haass, L., Meyers, P.A., Vidal, L. (2002): The late Miocene onset of high productivity in the Benguela Current upwelling system as part of a global pattern. - Mar. Geol., 180(1-4):87-103. Kastanja, M.M., Diekmann, B., Henrich, R. (2006): Controls on carbonate and terrigenous deposition in the incipient Benguela upwelling system during the middle to the late Miocene (ODP Sites 1085 and 1087).- P3, 241 (3-4):515-530. Roters, B., Henrich, R. (in press): The Middle to Late Miocene climatic development of Southwest Africa derived from the sedimentological record of ODP Site 1085A.- Intl. Jour. Earth Sci., DOI: 10.1007/s00531-008-0398-9. Westerhold, T., Bickert, T., Röhl, U. (2005): Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations.- P3, 217 (3-4):205-222.

  11. Minerals

    NSDL National Science Digital Library

    Mrs. Walls

    2011-01-30

    Create a poster about minerals! Directions: Make a poster about minerals. (20 points) Include at least (1) large picture (15 points) on your poster complete with labels of every part (10 points). (15 points) Include at least three (3) facts about minerals. (5 points each) (15 points) Write at ...

  12. Abundance and diversity of total and nitrifying prokaryotes as influenced by biochemical quality of organic inputs combined with mineral nitrogen

    NASA Astrophysics Data System (ADS)

    Muema, Esther; Vanlauwe, Bernard; Röhl, Carolin; Cadisch, Georg; Rasche, Frank

    2014-05-01

    Ammonia-oxidizing bacteria and archaea (AOB, AOA) co-exist in soil, but they respond differently to distinct fertilization strategies in agricultural soils. Accordingly, effects of organic inputs and combination with mineral nitrogen (N) on AOB and AOA remain poorly understood. The aim of this study was to compare soil amendment with contrasting quality of organic inputs (i.e., high quality Tithonia diversifolia (TD; C/N ratio: 13, Lignin: 8.9 %; Polyphenols: 1.7 %), intermediate quality Calliandra calothyrsus (CC; 13; 13; 9.4) and low quality Zea mays (ZM; 59; 5.4; 1.2)), and combination with mineral N on the abundance (i.e., DNA-based gene quantification) and community structure (i.e., T-RFLP analysis) of total bacterial and archaea (16S rRNA gene), as well as AOB and AOA (targeting the amoA gene) communities in a Humic Nitisol. Soils (0-15 cm depth) were sampled prior to the onset of the rainy season in March 2012 in a 10 years old field experiment established in the central highlands of Kenya in 2002. Since the start of the experiment, organic inputs were applied annually at a rate of 4 Mg C ha-1 and mineral N twice a year as calcium ammonium nitrate (5Ca(NO3)2NH4NO3) at a rate of 120 kg N ha-1 growing season-1. Quality of organic inputs posed only a significant effect on the AOB community structure between TD versus ZM and CC versus ZM. Moreover, TD significantly increased the size of AOB over ZM input, while higher abundances for total bacteria, total archaea and AOA were measured in ZM and TD over CC. This was explained by high and available N in TD, but low lignin and polyphenol contents in TD and ZM as opposed to CC. AOB responded sensitively (i.e., complete community structure separation) to mineral N, specifically when combined with low quality ZM. Hence, AOB community was specifically responsive to quality of organic inputs and combination of low organic input with mineral N over AOA and total prokaryotic communities in the studied soil. The results presented were however, generated on one occasion soil sampling representing the effect of continuous organic and inorganic fertilizer application for ten years. We therefore recommend for prospective research, further investigations to rule out the temporal (short-term) variations of microbial decomposer dynamics at different crops growth stages during a cropping season as well as comparing different soil types.

  13. Quantifying mineral abundances of complex mixtures by coupling spectral deconvolution of SWIR spectra (2.1-2.4 ?m) and regression tree analysis

    USGS Publications Warehouse

    Mulder, V.L.; Plotze, Michael; de Bruin, Sytze; Schaepman, Michael E.; Mavris, C.; Kokaly, Raymond F.; Egli, Markus

    2013-01-01

    This paper presents a methodology for assessing mineral abundances of mixtures having more than two constituents using absorption features in the 2.1-2.4 ?m wavelength region. In the first step, the absorption behaviour of mineral mixtures is parameterised by exponential Gaussian optimisation. Next, mineral abundances are predicted by regression tree analysis using these parameters as inputs. The approach is demonstrated on a range of prepared samples with known abundances of kaolinite, dioctahedral mica, smectite, calcite and quartz and on a set of field samples from Morocco. The latter contained varying quantities of other minerals, some of which did not have diagnostic absorption features in the 2.1-2.4 ?m region. Cross validation showed that the prepared samples of kaolinite, dioctahedral mica, smectite and calcite were predicted with a root mean square error (RMSE) less than 9 wt.%. For the field samples, the RMSE was less than 8 wt.% for calcite, dioctahedral mica and kaolinite abundances. Smectite could not be well predicted, which was attributed to spectral variation of the cations within the dioctahedral layered smectites. Substitution of part of the quartz by chlorite at the prediction phase hardly affected the accuracy of the predicted mineral content; this suggests that the method is robust in handling the omission of minerals during the training phase. The degree of expression of absorption components was different between the field sample and the laboratory mixtures. This demonstrates that the method should be calibrated and trained on local samples. Our method allows the simultaneous quantification of more than two minerals within a complex mixture and thereby enhances the perspectives of spectral analysis for mineral abundances.

  14. Occurrence, abundance and origin of minerals in coals and coal ashes

    Microsoft Academic Search

    Stanislav V. Vassilev; Christina G. Vassileva

    1996-01-01

    The mineralogy of coal and coal ash samples from a wide variety of deposits worldwide has been studied by X-ray diffractometry, light microscopy, SEM, TEM, and DTA-TGA methods. The common major minerals identified in the crystalline matter of coals are quartz, kaolinite, illite, calcite, pyrite, plagioclase, K-feldspar and gypsum, and occasionally dolomite, ankerite, siderite, Fe oxyhydroxides and sulphates. A number

  15. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2000-01-01

    Part of the 1999 Industrial Minerals Review. The clay and shale market in 1999 is reviewed. In the U.S., sales or use of clay and shale increased from 26.4 million st in 1998 to 27.3 million st in 1999, with an estimated 1999 value of production of $143 million. These materials were used to produce structural clay products, lightweight aggregates, cement, and ceramics and refractories. Production statistics for clays and shales and for their uses in 1999 are presented.

  16. An investigation of some of the effects of anhydrous ammonia on the clay minerals montmorillonite and illite 

    E-print Network

    Whiteley, Eli Lamar

    1959-01-01

    type of structure which is formed between the layers of the clay particles. An additional water layer of similar structure is taken up by the ions at higher relative humidities. In montmorillonite saturated with sodium, potassium, or cesium..., the cations apparently are not hydrated, but in the case of the sodium ion, the oriented water layer may grow to very great thicknesses. The lithium ion, which is hydrated, is sur? rounded by three molecules of water of hydration. Calcium and magnesium...

  17. South Asian monsoon history over the past 60 kyr recorded by radiogenic isotopes and clay mineral assemblages in the Andaman Sea

    NASA Astrophysics Data System (ADS)

    Ali, Sajid; Hathorne, Ed C.; Frank, Martin; Gebregiorgis, Daniel; Stattegger, Karl; Stumpf, Roland; Kutterolf, Steffen; Johnson, Joel E.; Giosan, Liviu

    2015-02-01

    The Late Quaternary variability of the South Asian (or Indian) monsoon has been linked with glacial-interglacial and millennial scale climatic changes but past rainfall intensity in the river catchments draining into the Andaman Sea remains poorly constrained. Here we use radiogenic Sr, Nd, and Pb isotope compositions of the detrital clay-size fraction and clay mineral assemblages obtained from sediment core NGHP Site 17 in the Andaman Sea to reconstruct the variability of the South Asian monsoon during the past 60 kyr. Over this time interval ?Nd values changed little, generally oscillating between -7.3 and -5.3 and the Pb isotope signatures are essentially invariable, which is in contrast to a record located further northeast in the Andaman Sea. This indicates that the source of the detrital clays did not change significantly during the last glacial and deglaciation suggesting the monsoon was spatially stable. The most likely source region is the Irrawaddy river catchment including the Indo-Burman Ranges with a possible minor contribution from the Andaman Islands. High smectite/(illite + chlorite) ratios (up to 14), as well as low 87Sr/86Sr ratios (0.711) for the Holocene period indicate enhanced chemical weathering and a stronger South Asian monsoon compared to marine oxygen isotope stages 2 and 3. Short, smectite-poor intervals exhibit markedly radiogenic Sr isotope compositions and document weakening of the South Asian monsoon, which may have been linked to short-term northern Atlantic climate variability on millennial time scales. This article was corrected on 18 MAR 2015. See the end of the full text for details.

  18. Clay complexes support HDS catalyst.

    SciTech Connect

    Marshall, C. L.; Carrado, K.; Chemical Engineering

    2000-01-01

    Hydroprocessing represents a crucial component of petroleum refining operations both in terms of environmental and economic considerations. Regulations concerning maximum amount of sulfur content of gasoline and emissions of sulfur-oxide compounds upon combustion are becoming more and more stringent. One 1994-2000 focus of Argonne National Laboratory (ANL) has been the development of catalysts for hydrodesulfurization (HDS). Typical HDS catalysts are comprised of Co-Mo sulfides or Ni-Mo sulfides on an alumina support. Modification of the pore structure of the support has generated great attention among researchers. Most desulfurization test reactions have used dibenzothiophene (DBT) as the model compound to test various configurations of support material with Co-Mo-S and Ni-Mo-S catalysts. In this testing, the desired product would be biphenyl and hydrogen sulfide (H{sub 2}S). A competing reaction creates cyclohexylbenzene by saturating one aromatic ring prior to desulfurization. Ring saturation requires more costly hydrogen and is not desirable. Fortunately, a more effective catalyst for adding hydrogen at the sulfur site with hydrogenating the aromatic rings has been found. However, this has only been tested on DBT. HDS uses various types of catalysts to add hydrogen to reduce unwanted sulfur compounds. Typically this requires expensive, high-pressure, high-temperature equipment to produce the environmentally friendly low-sulfur fuels. ANL scientists identified several new desulfurization catalysts with improved HDS activity and selectivity. From these new catalysts, it may be possible to achieve HDS processing at lower temperature and pressure. The catalysts used for HDS at ANL are various clay complexes. Natural clays have a history of use in the hydroprocessing industry since they are abundant and inexpensive. ANL's approach is to create synthetic organo-clay complexes (SOCC). An advantage of SOCCs is that the pore size and distribution can be controlled by the synthesis method, and the purity of the synthetic clays is high compared to naturally occurring clay minerals.

  19. Variability of fluvial sediment supply to the Laptev Sea continental margin during Late Weichselian to Holocene times: implications from clay-mineral records

    NASA Astrophysics Data System (ADS)

    Müller, Claudia; Stein, Ruediger

    2000-08-01

    Three sediment cores from the Laptev Sea continental margin were investigated for their clay mineralogy by X-ray diffraction to study the fluvial sediment supply since the late Weichselian. In the study area, the clay-mineral composition of surface sediments is characterized by distinct regional variations. The source area for smectite in the eastern Eurasian Basin is the Putoran Plateau drained by the Khatanga and Yenisei rivers. Currents caused by river discharge and the inflow of Atlantic water masses along the Eurasian continental margin are responsible for sediment distribution. In the sediment cores, smectite and illite contents show an opposite trend which mainly results from variable smectite supply. During MIS 2 the amount of smectite on the Laptev Sea continental margin never exceeds 10 rel.%. Probably, reduced river discharge and the lowered sea level during MIS 2 caused a decreased sediment supply to the Laptev Sea. Additionally, the Putoran Plateau was covered by an ice sheet during the Late Weichselian preventing the erosion of smectite-rich soils. In contrast, maximum smectite contents (up to 30 rel.%) in Holocene sediments result from increased sediment input by the Khatanga River and from the Kara Sea through the Vilkitsky Strait and via St. Anna Trough into the western Laptev Sea.

  20. Clay and framework mineralogy, cation exchange capacity, matrix density, and porosity from geochemical well logging in Kern County, California

    SciTech Connect

    Herron, M.M.; Grau, J.A.

    1987-05-01

    Elemental concentrations of several inorganic elements were determined in a continuous basis with depth using the Schlumberger gamma-ray spectrometry (GST) and natural gamma-ray spectrometry (NGS) logs in a Santa Fe Energy Company well in the Kern Front field in Bakersfield, California. Logs of Al, Si, Ca, K, Fe, Ti, and non-pore H were processed by a matrix multiplication procedure, used previously for a Venezuelan well, into estimated abundances of quartz, feldspar, calcite, ilmenite, and the clay minerals kaolinite, illite, and smectite. A total of 64 core-plug samples were analyzed for elemental content by x-ray fluorescence and neutron activation analysis and for mineralogy by bulk and < 4 ..mu.. clay x-ray diffraction analyses. Log-derived elemental concentrations and mineral abundances show good agreement with the core values. Cation exchange capacity (CEC) is estimated from the abundances of the clay minerals and typical values for these clays. The CEC log agrees well with CEC values determined on the core samples. The mineral abundance logs also permit an estimation of the average matrix density as a function of depth, derived from typical grain densities for each mineral phase. This matrix density log, combined with the bulk density log, yields a porosity log that compares well with over 200 measurements on core.

  1. Varied pathways of river-borne clay minerals in a near-shore marine region: A case study of sediments from the Elbe- and Weser rivers, and the SE North Sea

    NASA Astrophysics Data System (ADS)

    Pache, Tadeus; Brockamp, Olaf; Clauer, Norbert

    2008-07-01

    The <2 ?m fraction of 45 sediment samples from the Elbe and Weser rivers and from the southeastern North Sea (German Bight) was analyzed for its contents of clay minerals and selected chemical elements. This was done to provide new information to the controversial question about the origin and distribution of clays in this near-shore marine region. The proportions of smectite, chlorite, illite and kaolinite were determined from intensities of the (001) basal reflection of the XRD pattern using weighted integrated factors and IR-mineral spectra, which were fitted to the values of the chemical analyses. Illite - the major clay mineral - was characterized by its K/Rb ratios and K-Ar ages. Anthropogenic metal contamination was demonstrated by the Cu, Pb and Zn contents. The results outline significant systematic changes in the proportions of clay minerals, in the K/Rb-ratios, the K-Ar data, and in the heavy-metal contents at the fluvial-estuarine transition and towards the marine environment. These changes result from a progressive mixing of suspended fluvial material with reworked Pleistocene sediments at the bottom of the North Sea. Near shore, the proportion of reworked Pleistocene sediment amounts only 20-30%. The mixture is distributed within a 100 km wide zone, mainly by currents parallel to the coast. It is also transported during flood tide into the estuaries, where it is mixed further with suspended fluvial material. The K/Rb ratios and K-Ar dates obtained from illite prove to be particularly useful for modeling the mixing of the clay minerals as well as their distribution patterns and origin.

  2. Comparison of the sorption behaviors and mechanisms of perfluorosulfonates and perfluorocarboxylic acids on three kinds of clay minerals.

    PubMed

    Zhao, Lixia; Bian, Jingna; Zhang, Yahui; Zhu, Lingyan; Liu, Zhengtao

    2014-11-01

    The sorption of four perfluoroalkyl acids (PFAAs) [perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA)] on three typical minerals [montmorillonite (MM), kaolinite (KL) and hematite (HM)] was studied. The sorption of PFOS and PFHxS was much stronger than PFOA and PFHxA. The sorption of each PFAA on the minerals followed an order of HM>KL>MM, even though MM was positively while KL and HM were negatively charged, implying that the sorption is driven by some other interactions besides electrostatic attraction. The sorption decreased with an increase in pH and a decrease in ionic strength of the solution, and their impacts on PFOS were much stronger than other three PFAAs. Surface complexing and hydrogen-bonding could make great contributions to the sorption of PFOS on the minerals. The results are important for understanding the transport and fate of PFAAs in sediment and ground water. PMID:25113183

  3. Trace element abundance determinations by Synchrotron X Ray Fluorescence (SXRF) on returned comet nucleus mineral grains

    NASA Technical Reports Server (NTRS)

    Flynn, G. J.; Sutton, S. R.

    1989-01-01

    Trace element analyses were performed on bulk cosmic dust particles by Proton Induced X Ray Emission (PIXE) and Synchrotron X Ray Fluorescence (SXRF). When present at or near chondritic abundances the trace elements K, Ti, Cr, Mn, Cu, Zn, Ga, Ge, Se, and Br are presently detectable by SXRF in particles of 20 micron diameter. Improvements to the SXRF analysis facility at the National Synchrotron Light Source presently underway should increase the range of detectable elements and permit the analysis of smaller samples. In addition the Advanced Photon Source will be commissioned at Argonne National Laboratory in 1995. This 7 to 8 GeV positron storage ring, specifically designed for high-energy undulator and wiggler insertion devices, will be an ideal source for an x ray microprobe with one micron spatial resolution and better than 100 ppb elemental sensitivity for most elements. Thus trace element analysis of individual micron-sized grains should be possible by the time of the comet nucleus sample return mission.

  4. Linking dynamics of soil microbial phospholipid fatty acids to carbon mineralization in a 13C natural abundance experiment: Impact of heavy metals and acid rain

    Microsoft Academic Search

    Michael Stemmer; Andrea Watzinger; Karl Blochberger; Georg Haberhauer; Martin H. Gerzabek

    2007-01-01

    A 13C natural abundance experiment including GC-c-IRMS analysis of phospholipid fatty acids (PLFAs) was conducted to assess the temporal dynamics of the soil microbial community and carbon incorporation during the mineralization of plant residues under the impact of heavy metals and acid rain. Maize straw was incorporated into (i) control soil, (ii) soil irrigated with acid rain, (iii) soil amended

  5. Sea-level and provenance controlled clay mineral assemblage since the last 19 ka in the southern South China Sea: records of Core MD05-2894 off the Sunda Shelf

    NASA Astrophysics Data System (ADS)

    Wang, H.; Liu, Z.; Colin, C.; Sathiamurthy, E.; Hantoro, W. S.; Zhao, Y.

    2010-12-01

    High-resolution clay mineral assemblage at Core MD05-2894 (7°2.25'N, 111°33.11'E, water depth 1982 m) in the southern South China Sea is used to investigate the provenance and transport process of fine-grained sediments since the last 19 ka. In order to perform the source analysis, clay minerals in surface sediments of various potential source areas are also analyzed, including the Mekong River, Malay Peninsula, Sumatra, Borneo, and the Sunda Shelf. Clay mineralogical results at Core MD05-2894 indicate the sea level rise as the principal factor to drive provenance changes. During the late glacial stage, the Sunda Shelf was exposed. High values of smectite (average 32%) and kaolinite (27%) at the core suggest a large contribution of fine-grained sediments transported by the potential Sunda paleo-drainage system from Malaysia Peninsula and Sumatra, where kaolinite and smectite are rich. During the deglaciation when the sea level rises, illite and chlorite contents increased with a similar pattern, whereas kaolinite and smectite contents decreased, suggesting more sediment contribution from the Mekong River and Northwest Borneo. During the Holocene, variations in four clay mineral contents keep relatively stable with more illite and chlorite contents than those of the deglaciation and last glacial stage, indicating a mixture of various provenances.

  6. Ball clay

    USGS Publications Warehouse

    Virta, Robert L.

    2010-01-01

    The article reports on the global market performance of ball clay in 2009 and presents an outlook for its 2010 performance. Several companies mined ball call in the country including Old Hickey Clay Co., Kentucky-Tennessee Clay Co., and H.C. Spinks Clay Co. Information on the decline in ball clay imports and exports is also presented.

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

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  8. Clays as prebiotic photocatalysts

    NASA Technical Reports Server (NTRS)

    Coyne, L. M.; Lawless, J.; Lahav, N.; Sutton, S.; Sweeney, M.

    1981-01-01

    Clay minerals catalyze peptide bond formation in fluctuating environments. A number of plausible mechanisms have been proposed and tested. The possibility that clays may actually be energizing the reaction by means of electronic excitation, creating mobile or trapped holes and electrons in the lattice, is explored. It has been discovered that clays emit light upon dehydration. The correlation between dehydration-induced, or thermoluminescent, processes and the yield of glycine oligomers after treatments known to affect the luminescent yields is being tested, in an effort to understand the catalytic mechanism

  9. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2006-01-01

    In 2005, four companies including H.C. Spinks Clay, Kentucky-Tennessee Clay, Old Hickory Clay and Unimin mined ball clay in four states. Based on a preliminary survey of the ball clay industry, production reached 1.32 Mt valued at $53.3 million. Tennessee was the leading ball clay producer state with 61% of domestic production, followed by Texas, Mississippi and Kentucky.

  10. Microtektites and Associated Minerals in the Iridium-Rich Layer of Marine Clay From the Central North Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Leung, I. S.

    2014-12-01

    Our study is based on a sample derived from a deep sea core (GPC3) from the mid-Pacific Ocean floor north of the Hawaiian Islands, provided by Jim Broda, Woods Hole Oceanographic Institution. The 65 Ma K/T boundary layer was identified by measurements of magnetic susceptibility (Doh, 1987) and Ir anomaly (Kyte et al., 1995) which peaked at a down-hole depth of 2055-2056 cm. Our sample of red clay was about 5 cubic cm in size. After wet-sieving for the size fraction greater than 38 microns, we hand-picked grains of interest under a binocular microscope. We found 40 microtektites (glass spherules, mostly devitrified), 12 olive-green aggregates composed of talc/magnetite, and 3 green and blue crystals of silicon carbide (SiC). There are many quartz grains having decorated deformation lamellae or mosaic structures. The olive-green talc/magnetite particles have textures and composition similar to materials found in chondritic meteorites, whereas, SiC crystals are known to occur in carbonaceous chondrites. These particles seem to implicate an affinity to meteorites. Ir-rich deposits world-wide are believed to have settled from dust produced by the Chicxulub Impact, but what object from space created the impact crater is rather uncertain. Our results reported here cannot rule out the possiblilty of impact by comets, because the nature of cometary dust particles are not very well known.

  11. Magnetic composites from minerals: study of the iron phases in clay and diatomite using Mössbauer spectroscopy, magnetic measurements and XRD

    NASA Astrophysics Data System (ADS)

    Cabrera, M.; Maciel, J. C.; Quispe-Marcatoma, J.; Pandey, B.; Neri, D. F. M.; Soria, F.; Baggio-Saitovitch, E.; de Carvalho, L. B.

    2014-01-01

    Magnetic particles as matrix for enzyme immobilization have been used and due to the enzymatic derivative can be easily removed from the reaction mixture by a magnetic field. This work presents a study about the synthesis and characterization of iron phases into magnetic montmorillonite clay (mMMT) and magnetic diatomaceous earth (mDE) by 57Fe Mössbauer spectroscopy (MS), magnetic measurements and X-ray diffraction (XRD). Also these magnetic materials were assessed as matrices for the immobilization of invertase via covalent binding. Mössbauer spectra of the magnetic composites performed at 4.2 K showed a mixture of magnetite and maghemite about equal proportion in the mMMT, and a pure magnetite phase in the sample mDE. These results were verified using XRD. The residual specific activity of the immobilized invertase on mMMT and mDE were 83 % and 92.5 %, respectively. Thus, both magnetic composites showed to be promising matrices for covalent immobilization of invertase.

  12. Sorption of N2 and EGME vapors on some soils, clays, and mineral oxides and determination of sample surface areas by use of sorption data

    USGS Publications Warehouse

    Chiou, C.T.; Rutherford, D.W.; Manes, M.

    1993-01-01

    Vapor sorption isotherms of ethylene glycol monoethyl ether (EGME) at room temperature and isotherms of N2 gas at liquid nitrogen temperature were determined for various soils and minerals. The N2 monolayer capacities [Qm (N2)] were calculated from the BET equation and used to determine the surface areas. To examine whether EGME is an appropriate adsorbate for determination of surface areas, the apparent EGME monolayer capacities [Qm (EGME)ap] were also obtained by use of the BET equation. For sand, aluminum oxide, kaolinite, hematite, and synthetic hydrous iron oxide, which are relatively free of organic impurity and expanding/solvating minerals, the Qm (EGME)ap values are in good conformity with the corresponding Qm (N2) values and would give surface areas consistent with BET (N2) values. For other samples (Woodburn soil, a natural hydrous iron oxide, illite, and montmorillonite), the Qm (EGME)ap values overestimate the Qm (N2) values from a moderate to a large extent, depending on the sample. A high-organic-content peat shows a very small BET (N2) surface area; the EGME/ peat isotherm is linear and does not yield a calculation of the surface area. Large discrepancies between results of the two methods for some samples are attributed to the high solubility of polar EGME in soil organic matter and/ or to the cation solvation of EGME with solvating clays. The agreement for other samples is illustrative of the consistency of the BET method when different adsorbates are used, so long as they do not exhibit bulk penetration and/or cation solvation. ?? 1993 American Chemical Society.

  13. Early diagenesis and clay mineral adsorption as driving factors of metal pollution in sediments: the case of Aveiro Lagoon (Portugal).

    PubMed

    Martins, Maria Virgínia Alves; Mane, Miguel Ângelo; Frontalini, Fabrizio; Santos, José Francisco; da Silva, Frederico Sobrinho; Terroso, Denise; Miranda, Paulo; Figueira, Rubens; Laut, Lazaro Luiz Mattos; Bernardes, Cristina; Filho, João Graciano Mendonça; Coccioni, Rodolfo; Dias, João M Alveirinho; Rocha, Fernando

    2015-07-01

    This work aims to define the factors driving the accumulation of metals in the sediment of the lagoon of Aveiro (Portugal). The role of initial diagenetic processes in controlling trace metal retention in surface sediment is traced by mineralogy, magnetic susceptibility and geochemical analyses. Although several studies have focused on the metal distribution in this polihaline and anthropized coastal lagoon, most of them have been solely focused on the total metal concentrations. This study instead represents the first attempt to evaluate in a vast area of the Aveiro Lagoon the role of biogeochemical processes in metal availability and distribution in three extracted phases: exchangeable cations adsorbed by clay and elements co-precipitated with carbonates (S1), organic matter (S2) and amorphous Mn hydroxides (S3). According to the sediment guideline values, the sediment is polluted by, for instance, As and Hg in the inner area of the Murtosa Channel, Pb in the Espinheiro Channel, Aveiro City canals and Aveiro Harbour, and Zn in the northern area of the Ovar Channel. These sites are located near the source areas of pollutants and have the highest total available concentrations in each extracted phase. The total available concentrations of all toxic metals are however associated, firstly, with the production of amorphous Mn hydroxides in most of the areas and, secondly, with adsorption by organic compounds. The interplay of the different processes implies that not all of the sites near pollution sources have polluted surface sediment. The accumulation of metals depends on not only the pollution source but also the changing in the redox state of the sediments that may cause alterations in the sediment retention or releasing of redox-sensitive metals. Results of this work suggest that the biogeochemical processes may play a significant role in the increase of the pollutants in the sediment of the Aveiro Lagoon. PMID:25666475

  14. Enzyme-clay interactions and their impact on transformations of natural and anthropogenic organic compounds in soil

    SciTech Connect

    Naidja, A.; Huang, P.M.; Bollag, J.M.

    2000-06-01

    Soil is a living system in which enzymes are present either free in solution or bound to clay and clay-humus complexes. Enzyme-clay interactions play a key role in transforming organic compounds in soil environments where the decomposition and synthetic processes are largely catalyzed by enzymes. Scientific evidence indicates that mineral colloids take part in the catalysis of degradative and synthetic reactions of organic compounds. Such information is essential to understanding the role of mineral colloids, the hidden half of the enzyme-mineral colloid complexes, in catalytic reactions. Despite the abundant literature on the enzyme interactions with pure crystalline aluminosilicates, the nature of enzyme association with soil constituents, including both clean and coated clay minerals and other mineral colloids, and the effect on soil processes still remain unclear. This study integrates the existing information, including recent findings on enzyme-mineral colloid interactions and their effect on natural and anthropogenic organic compound transformation in soil. Further, the study focuses on the catalytic role of enzyme-clay complex surfaces in toxic industrial and agricultural compound bioremediation in soil and water environments.

  15. Rare-earth mobility across an interface and also beyond between selected soil clay mineral particles and roots of a selected plant interface: A view based on an experimental study.

    NASA Astrophysics Data System (ADS)

    Weber, R.; Schneider, J.; Chaudhuri, S.

    2009-04-01

    Some recent suggestions of the essentiality of rare-earth elements (REE) for plants have generated much interest in gathering information about processes of mineral weathering in root environments and acquisition of REE by plants from such environments. An additional recent interest on plant acquisition of metals is gaining ground in finding out the measures of plant contribution of various metals present in river water at a regional or global scale. To monitor the path of transfer of REE from a clay mineral rich soil medium to roots of a plant, a species of poplar plant (Populus eugenei) was grown, using small cuttings of stems from a previous poplar plant, in a Ca-smectite clay as a soil medium under a laboratory condition. The <2-micrometer fraction of the clay prior to the planting of the poplar had a total REE concentration of 275 ppm . In contrast , the root attached >2-micron fraction clay had a concentration of 203 ppm. The relatively low concentration for the root clay was accompanied by a slight enrichment in LREE (light rare-earth element) with a small Ce negative anomaly as compared to the equivalent fine clay fraction having no influence of the plant. The translocation of the clay REE from the apparently rhizosphere environment to the roots was, as expected in conformity with the REE fractionation that was observed in the root clays, marked by an enrichment in HREE (heavy rare-earth element), but with some positive Ce, Eu, and Gd anomalies, for the plant roots relative to the clays attached to the roots. The total REE concentration of the plant roots was nearly 39 ppm per gram of dry material. New stems grown from earlier (older) stems had REE concentrations of about 0.19 ppm per gram of dry material, whereas old stems from which new shoots grew (making up the new stems) had concentrations of about 0.22 ppm per gram of dry material. The new stems were found to be only slightly enriched in LREE but with a positive Eu anomaly relative to the older stems from which the new stems grew. The leaves that grew from new stems had a REE concentration of nearly 14 ppm per gram of dry material. The new leaves, however, were HREE enriched with negative anomalies of Sm, Eu, and Gd relative to the new stems from which the leaves grew. The REE patterns in plant organs are reflective of intercellular processes of enzyme influence coupled with reductive adsorptive mechanisms. If river waters could be found with an HREE trend for the dissolved REE, plant organs releasing such REE following decomposition could be a contributing factor to this trend in river waters.

  16. Mineral buffering of contaminated ground water compositions at a hazardous waste site in southwestern Louisiana

    Microsoft Academic Search

    J. S. Hanor; S. Su; K. M. McManus

    1995-01-01

    A study has been made of natural geologic controls on preremediation water chemistry at a hazardous waste site where ground waters contained a variety of organic contaminants, including from <1μg\\/L to 3.5 g\\/L 1,2-dichlorethane. Quartz, plagioclase feldspar, and K-feldspar are the most abundant non-clay minerals in the sand, slit, and clay beds at the site. Calcite and dolomite occur in

  17. Bioremediation of a mineral soil with high contents of clay and organic matter contaminated with herbicide 2,4-dichlorophenoxyacetic acid using slurry bioreactors: Effect of electron acceptor and supplementation with an organic carbon source

    Microsoft Academic Search

    Ireri Robles-González; Elvira Ríos-Leal; Ronald Ferrera-Cerrato; Fernando Esparza-García; Noemí Rinderkenecht-Seijas; Héctor M. Poggi-Varaldo

    2006-01-01

    Ad situ remediation techniques appear as an interesting alternative for the treatment of polluted solid matrices that are not amenable to in situ remediation, such as soils characterized by high contents of clay and organic matter coupled to low hydraulic conductivity and permeability. In this work, the removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from an agricultural mineral soil with high contents

  18. Clay Play

    ERIC Educational Resources Information Center

    Rogers, Liz; Steffan, Dana

    2009-01-01

    This article describes how to use clay as a potential material for young children to explore. As teachers, the authors find that their dialogue about the potential of clay as a learning medium raises many questions: (1) What makes clay so enticing? (2) Why are teachers noticing different play and conversation around the clay table as compared to…

  19. Clay Exploration

    NSDL National Science Digital Library

    2012-06-26

    In this activity, learners explore the possibilities of clay as a natural material. At three stations, learners create sculptures, use natural items such as small pebbles, twigs, and pinecones to embellish clay structures, and paint with clay. These activities help learners discover the sensory qualities of clay as a medium.

  20. The Precursor of the Cretaceous-Tertiary Boundary Clays at Stevns Klint, Denmark, and DSDP Hole 465A

    NASA Astrophysics Data System (ADS)

    Kastner, M.; Asaro, F.; Michel, H. V.; Alvarez, W.; Alvarez, L. W.

    1984-10-01

    Results of detailed mineralogical, chemical, and oxygen isotope analyses of the clay minerals and zeolites from two Cretaceous-Tertiary (K/T) boundary regions, Stevns Klint, Denmark, and Deep Sea Drilling Project (DSDP) Hole 465A in the north central Pacific Ocean, are presented. In the central part of the Stevns Klint K/T boundary layer, the only clay mineral detected by x-ray diffraction is a pure smectite with >95 percent expandable layers. No detrital clay minerals or quartz were observed in the clay size fraction in these beds, whereas the clay minerals above and below the boundary layer are illite and mixed-layer smectite-illite of detrital origin as well as quartz. The mineralogical purity of the clay fraction, the presence of smectite only at the boundary, and the ? 18O value of the smectite (27.2 ± 0.2 per mil) suggest that it formed in situ by alteration of glass. Formation from impact rather than from volcanic glass is supported by its major element chemistry. The high content of iridium and other siderophile elements is not due to the cessation of calcium carbonate deposition and resulting slow sedimentation rates. At DSDP Hole 465A, the principal clay mineral in the boundary zone (80 to 143 centimeters) is a mixed-layer smectite-illite with >= 90 percent expandable layers, accompanied by some detrital quartz and small amounts of a euhedral authigenic zeolite (clinoptilolite). The mixed-layer smectite-illite from the interval 118 to 120 centimeters in the zone of high iridium abundance has a very low rare earth element content; the negative cerium anomaly indicates formation in the marine environment. This conclusion is corroborated by the ? 18O value of this clay mineral (27.1 ± 0.2 per mil). Thus, this mixed-layer smectite-illite formed possibly from the same glass as the K/T boundary smectite at Stevns Klint, Denmark.

  1. Octachlorodibenzodioxin formation on Fe(III)-montmorillonite clay.

    PubMed

    Gu, Cheng; Li, Hui; Teppen, Brian J; Boyd, Stephen A

    2008-07-01

    Polychlorinated dibenzo-p-dioxins (PCDDs) are ubiquitous and highly toxic environmental contaminants found in surface and subsurface soils and in clay deposits. Interestingly, the congener profiles of such PCDDs are inexplicably dissimilar to those of known anthropogenic (e.g., pesticide manufacture, waste incineration) or natural (e.g., forest fire) sources. Characteristic features of soil or clay-associated PCDDs are the dominance of octachlorodibenzo-p-dioxin (OCDD) as the most abundant congener and very low levels of polychlorinated dibenzofurans (PCDFs). These propensities led to the hypothesis of in situ PCDD formation in soils and geologic clay deposits. In this study, we demonstrate the formation of OCDD on the naturally occurring and widely distributed clay mineral montmorillonite under environmentally relevant conditions. When pentachlorophenol (PCP)was mixed with Fe(III)-montmorillonite, significant amounts of OCDD were rapidly (minutes to days) formed (approximately 5 mg OCDD/kg clay) at ambient temperature in the presence of water. This reaction is initiated by single electron transfer from PCP to Fe(III)-montmorillonite thereby forming the PCP radical cation. Subsequent dimerization, dechlorination, and ring closure reactions result in formation of OCDD. This study provides the first direct evidence for clay-catalyzed formation of OCDD supporting the plausibility of its in situ formation in soils. PMID:18678002

  2. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2011-01-01

    The article discusses the latest developments in the global ball clay mining industry, particularly in the U.S., as of June 2011. It cites several firms that are involved in ball clay mining in the U.S., including HC Spins Clay Co. Inc., the Imerys Group and Old Hickory Clay Co. Among the products made from ball clay are ceramic tiles, sanitaryware, as well as fillers, extenders and binders.

  3. minerals

    NASA Astrophysics Data System (ADS)

    Wildner, Manfred; Giester, Gerald; Kersten, Monika; Langer, Klaus

    2014-10-01

    Polarized electronic absorption spectra of colourless chalcocyanite, CuSO4, have been measured using microscope-spectrometric techniques. The spectra are characterized by a structured and clearly polarized band system in the near-infrared spectral range with components centred at 11,720, 10,545, 9,100, and 7,320 cm-1, which have been assigned to crystal field d- d transitions of Cu2+ cations in pseudo-tetragonally elongated CuO6 polyhedra with point symmetry C i (). The polarization behaviour is interpreted based on a D 2( C 2?) pseudo-symmetry. Crystal field calculations were performed for the actual triclinic point symmetry by applying the Superposition Model of crystal fields, as well as in terms of a `classic' pseudo-tetragonal crystal field approach yielding the parameters Dq (eq) = 910, Dt = 395, and Ds = 1,336 cm-1, corresponding to a cubically averaged Dq cub = 679 cm-1. A comparative survey on crystal fields in Cu2+ minerals shows that the low overall crystal field strength in chalcocyanite, combined with a comparatively weak pseudo-tetragonal splitting of energy levels, is responsible for its unique colourless appearance among oxygen-based Cu2+ minerals. The weak crystal field in CuSO4 can be related to the lower position of the SO4 2- anion compared to, e.g. the H2O molecule in the spectrochemical series of ligands.

  4. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2001-01-01

    Part of the 2000 annual review of the industrial minerals sector. A general overview of the common clay and shale industry is provided. In 2000, U.S. production increased by 5 percent, while sales or use declined to 23.6 Mt. Despite the slowdown in the economy, no major changes are expected for the market.

  5. Iodide uptake by negatively charged clay interlayers?

    PubMed

    Miller, Andrew; Kruichak, Jessica; Mills, Melissa; Wang, Yifeng

    2015-09-01

    Understanding iodide interactions with clay minerals is critical to quantifying risk associated with nuclear waste disposal. Current thought assumes that iodide does not interact directly with clay minerals due to electrical repulsion between the iodide and the negatively charged clay layers. However, a growing body of work indicates a weak interaction between iodide and clays. The goal of this contribution is to report a conceptual model for iodide interaction with clays by considering clay mineral structures and emergent behaviors of chemical species in confined spaces. To approach the problem, a suite of clay minerals was used with varying degrees of isomorphic substitution, chemical composition, and mineral structure. Iodide uptake experiments were completed with each of these minerals in a range of swamping electrolyte identities (NaCl, NaBr, KCl) and concentrations. Iodide uptake behaviors form distinct trends with cation exchange capacity and mineral structure. These trends change substantially with electrolyte composition and concentration, but do not appear to be affected by solution pH. The experimental results suggest that iodide may directly interact with clays by forming ion-pairs (e.g., NaI(aq)) which may concentrate within the interlayer space as well as the thin areas surrounding the clay particle where water behavior is more structured relative to bulk water. Ion pairing and iodide concentration in these zones is probably driven by the reduced dielectric constant of water in confined space and by the relatively high polarizability of the iodide species. PMID:26057987

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

    USGS Publications Warehouse

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

    1987-01-01

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

  7. Mineralogical and Chemical Analysis of Fracture and Matrix Minerals in Selected Samples of the Culebra Dolomite

    SciTech Connect

    Bryan, C.R.; Siegel, M.D.; Krumhansl, J.L.

    2001-03-01

    Contaminant release scenarios proposed for the Waste Isolation Pilot Plant (WIPP) repository suggest that the Culebra Dolomite member of the Rustler Formation could be an important radionuclide release path. This thin, vuggy, highly fractured unit is the most transmissive geologic unit overlying the WIPP. Many of the samples obtained from drill cores in the Culebra exhibit fractures that are lined with iron-oxyhydroxide-rich and clay-rich mineral coatings. The coatings are mineralogically distinct from the rock matrix, and may have sorptive characteristics that are different from a clay-poor dolomite matrix. Where locally abundant, such coatings could affect advective/diffusive exchange between matrix blocks and fractures and the accessible mineral surface area available for radionuclide adsorption. Clay minerals are present in the matrix and as fracture coatings in the samples from all the drill core locations examined in this study. Visual examination of rock sample surfaces in the H -19b7 core suggests that at least 7% of the total fracture surface area is coated with iron oxhydroxides or clays. In the samples from H-19b7, the amount of clay disseminated in the matrix varies from <1% to {approx}12 % by weight, and generally increases with stratigraphic height within the unit. In a suite of samples obtained from 12 other locations in the vicinity of the WIPP site, matrix samples from the Culebra contain 0.6--7% clay. These samples were taken from the more transmissive lower two-thirds of the unit (Culebra Units 2-4) which was considered to be the accessible portion of the unit in the WIPP Compliance Certification Application (CCA). Clay minerals also occur as clay-rich laminae and partings with the geometries of primary sedimentary structures and dissolution residues. Such partings are the loci of bedding plane fractures, and have the heaviest clay coatings found in the unit. Crosscutting fractures also commonly exhibit clay mineral coatings, but these are generally discontinuous and much thinner.

  8. Effect of cadmium on fungi and on interactions between fungi and bacteria in soil: influence of clay minerals and pH.

    PubMed

    Babich, H; Stotzky, G

    1977-05-01

    Fungi (Rhizopus stolonifer, Trichoderma viride, Fusarium oxysporum f. sp. conglutinans, Cunninghamella echinulata, and several species of Aspergillus and Penicillium) tolerated higher concentrations of cadmium (Cd) when grown in soil than when grown on laboratory media, indicating that soil mitigated the toxic effects of Cd. In soil amended with clay minerals, montmorillonite provided partial or total protection against fungistatic effects of Cd, whereas additions of kaolinite provided little or no protection. Growth rates of Aspergillus niger were inhibited to a greater extent by 100 or 250 mug of Cd per g in soil adjusted to pH 7.2 than in the same soil at its natural pH of 5.1. However, there were no differences in the growth rates of Aspergillus fischeri with 100 or 250 mug of Cd per g in the same soil, whether at pH 5.1 or adjusted to pH 7.2. Growth of A. niger and A. fischeri in a soil contaminated with a low concentration of Cd (i.e., 28 mug/g), obtained from a site near a Japanese smelter, did not differ significantly from growth in a soil collected some distance away and containing 4 mug of Cd per g. Growth of A. niger in sterile soil amended with 100 mug of Cd per g and inoculated with Bacillus cereus or Agrobacterium tumefaciens was reduced to a greater extent than in the same soil containing 100 mug of Cd per g but no bacteria. The inhibitory effects of Agrobacterium radiobacter to A. niger were slightly reduced in the presence of 100 mug of Cd per g, whereas the inhibitory effects of Serratia marcescens were enhanced. PMID:18085

  9. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2013-01-01

    Four companies — H.C. Spinks Clay Co., Inc., Imerys, Old Hickory Clay Co. and Unimin Corp. — mined ball clay in five U.S. states in 2012. Production, on the basis of preliminary data, was 900 kt (992,000 st), with an estimated value of $42.3 million. This was a slight increase in tonnage from 886 kt (977,000 st), with a value of $40.9 million in 2011. Tennessee was the leading ball clay producing state, with 63 percent of domestic production, followed by Texas, Mississippi, Kentucky and Indiana. Reported ball clay production from Indiana probably was fire clay rather than ball clay. About 69 percent of total ball clay production was airfloat, 20 percent was crude and 11 percent was water-slurried.

  10. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2011-01-01

    The article discusses the latest developments in the fire clay industry, particularly in the U.S., as of June 2011. It claims that the leading fire clay producer in the U.S. is the state of Missouri. The other major producers include California, Texas and Washington. It reports that the use of heavy clay products made of fire clay like brick, cement and lightweight aggregate has increased slightly in 2010.

  11. Investigating the Influence of Clay Mineralogy on Stream Bank Erodibility

    NASA Astrophysics Data System (ADS)

    Ambers, R. K.; Stine, M. B.

    2005-12-01

    Soil scientists concerned with erosion of agricultural fields and geotechnical engineers concerned with the mechanical behavior of soils under different conditions have both examined the role of clay mineralogy in controlling soil/sediment properties. Fluvial geomorphologists studying stream channel erosion and stability have focused more on the effects of particle-size distribution, vegetation and rooting. The clay mineralogy of bed and bank sediment has the potential to influence cohesiveness and erodibility, however. The goal of this study is to determine the influence of clay mineralogy on the erodibility of natural stream bank sediment, utilizing techniques drawn from pedology and soil mechanics. Bank samples were collected from eleven sites in small watersheds in central and western Virginia. To obtain sediment containing a range of different clay minerals, watersheds with different types of bedrock were chosen for sampling. Rock types included mafic to felsic metamorphic and igneous rocks, shale, sandstone, and limestone. Where stream bank materials were clearly stratified, different layers were sampled separately. X-ray diffraction of the clay-fraction of the sediment indicates the presence of kaolinite, illite, vermiculite, and mixed-layer clay minerals in various abundances in the different samples. Clay content is 9-46%, as determined by the hydrometer method, and textures range from silty clay and silt loam to clay loam and sandy loam. Organic mater contents range from 1-5% by the loss-on-ignition method. Bulk density of intact sediment samples averages 1.5 g/cc. Liquid limits range from 23-41 with one sample having a value of 65; plasticity indices range from 15-22. While these tests predict that the samples would show a range of mechanical behaviors, the channel morphology at the sampling sites was not strikingly different, all having steep cut banks eroded primarily by scour with no evidence of mass movement and most having a width/depth ratio around 4.5. The ASTM pinhole test for identifying dispersive clay soils is being adapted to measure erodibility of intact and remolded sediment samples in the laboratory to look for more subtle differences in behavior under erosive conditions. Factors such as the extent and method of sample compaction are being taken into account in order to standardize the method.

  12. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2013-01-01

    Four companies mined fire clay in three states in 2012. Production, based on a preliminary survey of the fire clay industry, was estimated to be 230 kt (254,000 st) valued at $6.98 million, an increase from 215 kt (237,000 st) valued at $6.15 million in 2011. Missouri was the leading producing state, followed by Colorado and Texas, in decreasing order by quantity. The number of companies mining fire clay declined in 2012 because several common clay producers that occasionally mine fire clay indicated that they did not do so in 2012.

  13. Smart Clays: SAFOD Samples Confirm the Key Role of Newly-formed Clays in Shallow Fault Zones

    NASA Astrophysics Data System (ADS)

    Schleicher, A.; van der Pluijm, B.; Warr, L. N.

    2013-12-01

    Analysis of fault rocks from drill-cores of the San Andreas Fault Observatory at Depth (SAFOD) project in Parkfield (CA) confirm our original hypothesis that active clay growth can occur locally at shallow conditions and that such clay localization affect fault mechanics and fault creep in particular. SAFOD fault rocks contain a variety of newly formed clay minerals including smectite, illite-smectite and chlorite-smectite, as well as illite and chlorite. Brecciated host rock fragments are abundantly coated by polished and/or striated thin-films of hydrated clay minerals, creating an interconnected and pervasive network of displacement surfaces. Ar encapsulation dating of mixed-layer nanocoatings demonstrates recent crystallization and reveal an 'older' fault strand (~8 Ma) at 3066 m measured depth and a 'younger' fault strand (~4 Ma) at 3296 m measured depth. Today, the younger strand is the site of active creep behavior, demonstrating continued (re)activation of clay-weakened zones. Recent experimental work on aseismically creeping segments of SAFOD samples showed frictional strengths that are significantly weaker than neighboring wall rocks, offering independent validation of our model. Using a range of analytical methods that include X-ray diffraction, X-ray goniometry, elemental analysis and electron microscopy, we determined the location and nature of smectitic clay minerals in borehole samples, to assess the extent of smectitic phases in space and depth, any fault zone fabric development, and the swelling behavior of smectitic phases within the fault zone. Beyond the occurrence of illite-smectite in these relatively shallow fault rocks, the localized concentration of chlorite-smectite can extend the role of smectitic clays to depths down to ~10 km. We conclude that ultrathin hydrous clay films, or nanocoatings, on displacement surfaces play a key role in influencing weak fault and creep behavior along the San Andreas Fault at Parkfield, and likely in shallow faults systems elsewhere. These results indicate that scenarios involving talc/serpentine phases or locally enhanced fluid pressure as explanations for mechanically weak crustal faults are not required.

  14. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2006-01-01

    In 2005, six companies mined fire clay in Missouri, Ohio and South Carolina. Production was estimate to be 300 kt with a value of $8.3 million. Missouri was the leading producer state followed by Ohio and South Carolina. For the third consecutive year, sales and use of fire clays have been relatively unchanged. For the next few years, sales of fire clay is forecasted to remain around 300 kt/a.

  15. Zirconium abundance in granulite-facies minerals, with implications for zircon geochronology in high-grade rocks

    Microsoft Academic Search

    Geoffrey Fraser; David Ellis; Stephen Eggins

    1997-01-01

    Zircon growth in high-grade metamorphic rocks may be triggered by net transfer reactions involving the breakdown of a phase bearing zirconium (Zr). We have measured the concentration of Zr in the major minerals in granulite-facies rocks of differing bulk composition. Both garnet and hornblende contain tens of parts per million Zr, and no other major phase contains significant Zr. Simple

  16. Chemical disaggregation of kaolinitic claystones (tonsteins and flint clays)

    USGS Publications Warehouse

    Triplehorn, D.M.; Bohor, B.F.; Betterton, W.J.

    2002-01-01

    The coarse, non-clay fraction of many flint-like kaolinitic claystones often contains mineral grains diagnostic of the claystone's origin and, in the case of tonsteins (altered volcanic ashes), may also provide minerals suitable for radiometric dating. Separation of the non-clay mineral fraction is often difficult because flint clays and flint-like clays resist slaking in water and thus are difficult to disaggregate. Chemical disaggregation of resistant kaolinitic claystones may be achieved by immersion in either hydrazine monohydrate or DMSO for periods ranging from one day to several weeks. Generally, hydrazine monohydrate works more quickly and efficiently than DMSO to disaggregate most kaolinitic claystones and flint clays.

  17. Clay composition and swelling potential estimation of soils using depth of absorption bands in the SWIR (1100-2500 nm) spectral domain

    NASA Astrophysics Data System (ADS)

    Dufréchou, Grégory; Granjean, Gilles; Bourguignon, Anne

    2014-05-01

    Swelling soils contain clay minerals that change volume with water content and cause extensive and expensive damage on infrastructures. Presence of clay minerals is traditionally a good estimator of soils swelling and shrinking behavior. Montmorillonite (i.e. smectite group), illite, kaolinite are the most common minerals in soils and are usually associated to high, moderate, and low swelling potential when they are present in significant amount. Characterization of swelling potential and identification of clay minerals of soils using conventional analysis are slow, expensive, and does not permit integrated measurements. SWIR (1100-2500 nm) spectral domain are characterized by significant spectral absorption bands related to clay content that can be used to recognize main clay minerals. Hyperspectral laboratory using an ASD Fieldspec Pro spectrometer provides thus a rapid and less expensive field surface sensing that permits to measure soil spectral properties. This study presents a new laboratory reflectance spectroscopy method that used depth of clay diagnostic absorption bands (1400 nm, 1900 nm, and 2200 nm) to compare natural soils to synthetic montmorillonite-illite-kaolinite mixtures. We observe in mixtures that illite, montmorillonite, and kaolinite content respectively strongly influence the depth of absorption bands at 1400 nm (D1400), 1900 nm (D1900), and 2200 nm (D2200). To attenuate or removed effects of abundance and grain size, depth of absorption bands ratios were thus used to performed (i) 3D (using D1900/D2200, D1400/D1900, and D2200/D1400 as axis), and (ii) 2D (using D1400/D1900 and D1900/D2200 as axis) diagrams of synthetic mixtures. In this case we supposed that the overall reduction or growth of depth absorption bands should be similarly affected by the abundance and grain size of materials in soil. In 3D and 2D diagrams, the mixtures define a triangular shape formed by two clay minerals as external envelop and the three clay minerals mixtures are located inside of the triangular shape. Clay composition of natural soils were estimated using 3D and 2D diagrams used as standard template from: (i) the average clay composition of the three closer mixtures when soil samples were plotted inside the triangular distribution of mixtures; and (ii) the closer mixture when the soil sample were plotted outside of the triangular distribution of mixtures. Comparison with X-ray diffraction analysis show reliable prediction of montmorillonite content that were used to estimate the swelling potential of soils. This method allows a simple, fast, and low cost method that classes soils into four swelling classes based on comparison with Methylene Blue test, and could be used as complementary or alternative method to traditional geotechnical analysis.

  18. Minerals in our Environment

    NSDL National Science Digital Library

    This downloadable poster (36 in. by 60 in.) describes how minerals are used in household substances and objects, listed by name, with numbers corresponding to locations in a typical house. For example, in the kitchen, appliances contain steel and copper, clay minerals are found in china, and table salt contains the mineral halite.

  19. Clay mineral status of paddy soils from the Tai Lake Region of China in relation to high paddy-rice productivity

    Microsoft Academic Search

    Kazuhiko Egashira; Soichi Iwashita; Shin-ichi Yamasaki

    1997-01-01

    Soil samples which were collected in the Tai Lake region of China during the tour organized after the 14th International Congress of Soil Science in 1990 were analyzed for the determination of the concentration of rare earth elements, particle-size distribution, and clay mineralogical composition. Paddy soils distributed in the plain and polder areas were derived from Xiashu loess. The concentration

  20. Fine-grained clay fraction (,0.2 {mu}m): An interesting tool to approach the present thermal and permeability state in active geothermal systems

    SciTech Connect

    Patrier, P.; Papapanagiotou, P.; Beaufort, D.; Traineau, H.; Bril, H.

    1992-01-01

    We have investigated by X-ray diffraction the very fine grained secondary minerals (< 0.2 {micro}m) developed in geothermal systems, in relation with their present thermal and permeability state. Because the smallest particles are the most reactive part of a rock, they are the youngest mineral phases of the geothermal fields. This study has been performed on two active geothermal fields: Milos field, Greece (130 < T < 320 C) and Chipilapa field, Salvador (90 < T < 215 C). In the Milos field, the mineralogical composition of the < 0.2 {micro}m clay fraction observed in the reservoir strongly differs from the overlying altered metamorphic schists in the presence of abundant quantities of saponite and talc/saponite interstratified minerals at unusually high temperature. These phases are considered to be kinetically control-led ''metastable'' minerals which rapidly evolve towards actinolite and talc for present temperatures higher than 300 C. Their occurrence is a good indicator of discharge in highly permeable zones. In the geothermal field of Chipilapa, the mineralogical composition of the < 0.2 {micro}m clay fractions fairly agrees with the temperatures presently measured in the wells, whereas several discrepancies may be pointed out from the compositions of coarser clay fractions (< 5 {micro}m) which contain minerals inherited from higher temperature stages. Permeable zones may be evidenced from an increase of expandable components in the interstratified minerals and a decrease of the coherent domain of the unexpandable clay particles (chlorite).

  1. Effect of electrolyte on the microstructure and yielding of aqueous dispersions of colloidal clay

    E-print Network

    Samim Ali; Ranjini Bandyopadhyay

    2015-07-10

    Na-montmorillonite is a natural clay mineral and is available in abundance in nature. The aqueous dispersions of charged and anisotropic platelets of this mineral exhibit non-ergodic kinetically arrested states ranging from soft glassy phases dominated by interparticle repulsions to colloidal gels stabilized by salt induced attractive interactions. When the salt concentration in the dispersing medium is varied systematically, viscoelasticity and yield stress of the dispersion show non-monotonic behavior at a critical salt concentration, thus signifying a morphological change in the dispersion microstructures. We directly visualize the microscopic structures of these kinetically arrested phases using cryogenic scanning electron microscopy. We observe the existence of honeycomb-like network morphologies for a wide range of salt concentrations. The transition of the gel morphology, dominated by overlapping coin (OC) and house of cards (HoC) associations of clay particles at low salt concentrations to a new network structure dominated by face-face coagulation of platelets, is observed across the critical salt concentration. We further assess the stability of these gels under gravity using electroacoustics. This study, performed for concentrated clay dispersions for a wide concentration range of externally added salt, is useful in our understanding of many geophysical phenomena that involve the salt induced aggregation of natural clay minerals.

  2. Mineral Composition and Abundance of the Rocks and Soils at Gusev and Meridiani from the Mars Exploration Rover Mini-TES Instruments

    NASA Technical Reports Server (NTRS)

    Christensen, P. R.; Wyatt, M. B.; Glotch, T. D.; Rogers, A. D.; Anwar, S.; Arvidson, R. E.; Bandfield, J. L.; Blaney, D. L.; Budney, C.; Calvin, W. M.

    2005-01-01

    The Miniature Thermal Emission Spectrometer (Mini-TES) has provided remote measurements of mineralogy, thermophysical properties, and atmospheric temperature profile and composition of the outcrops, rocks, spherules, and soils surrounding the Spirit and Opportunity Rovers. The mineralogy of volcanic rocks provides insights into the composition of the source regions and the nature of martian igneous processes. Carbonates, sulfates, evaporites, and oxides provide information on the role of water in the surface evolution. Oxides, such as crystalline hematite, provide insight into aqueous weathering processes, as would the occurrence of clay minerals and other weathering products. Diurnal temperature measurements can be used to determine particle size and search for the effects of sub-surface layering, which in turn provide clues to the origin of surficial materials through rock disintegration, aeolian transport, atmospheric fallout, or induration. In addition to studying the surface properties, Mini-TES spectra have also been used to determine the temperature profile in the lower boundary layer, providing evidence for convective activity, and have determined the seasonal trends in atmospheric temperature and dust and cloud opacity.

  3. Clay sized fraction and powdered whole-rock X-ray analyses from alluvial basin deposits in central and southern New Mexico

    USGS Publications Warehouse

    Anderholm, S.K.

    1985-01-01

    As part of the study of the water quality and geochemistry of Southwest Alluvial Basins (SWAB) in parts of Colorado, New Mexico, and Texas, which is a Regional Aquifer-System Analysis (RASA) program, whole rock x-ray analysis and clay-size fraction mineralogy (x-ray) analysis of selected samples from alluvial basin deposits were done to investigate the types of minerals and clay types present in the aquifers. This was done to determine the plausible minerals and clay types in the aquifers that may be reacting with groundwater and affecting the water quality. The purpose of this report is only to present the whole rock x-ray and clay-fraction mineralogy data. Nineteen surface samples or samples from outcrop of Tertiary and Quaternary alluvial basin deposits in the central and southern Rio Grande rift were collected and analyzed. The analysis of the samples consisted of grain size analysis, and clay-size fraction mineralogy and semiquantitative analysis of the relative abundance of different clay mineral groups present. (USGS)

  4. Graywacke matrix minerals: hydrothermal reactions with columbia river sediments.

    PubMed

    Hawkins, J W; Whetten, J T

    1969-11-14

    Experiments with sands chemically similar to graywackes produced "matrix" minerals at 250 degrees C and a water pressure of 1 kilobar. Starting materials were moderately well sorted sands containing abundant volcanic rock fragments and no detectable clay minerals. The results support the concept that graywacke matrix may form diagenetically by hydration and recrystallization of unstable clasts. Matrix need not be a recrystallized detrial fine fraction. Texture, therefore, is not a reliable criterion for sandstone classification. For graywackes, chemical composition may be more significant. PMID:17815746

  5. Rare earth element abundances in rocks and minerals from the Fiskenaesset Complex, West Greenland. [comparison with lunar anorthosites

    NASA Technical Reports Server (NTRS)

    Henderson, P.; Fishlock, S. J.; Laul, J. C.; Cooper, T. D.; Conard, R. L.; Boynton, W. V.; Schmitt, R. A.

    1976-01-01

    The paper reports activation-analysis determinations of rare-earth-element (REE) and other trace-element concentrations in selected rocks, plagioclase, and mafic separates from the Fiskenaesset Complex. The REE abundances are found to be very low and atypical in comparison with other terrestrial anorthosites. The plagioclases are shown to be characterized by a deficiency in heavy RE elements relative to light ones and a positive Eu anomaly, while the mafic separates are enriched in heavy rare earths and have no Eu anomaly, except in one sample. It is found that the bulk and trace-element abundances of the plagioclases are similar to those observed in some lunar anorthosites, but the degree of Eu anomaly is less in the plagioclases. The data are taken as confirmation of the idea that fractionation processes were involved in the origin of the Complex, and it is concluded that the Complex may have been produced from a magma generated by partial melting of a garnet-bearing source.

  6. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2012-01-01

    Five companies mined fire clay in four states in 2011. Production, based on a preliminary survey of the fire clay industry, was estimated to be 240 kt (265,000 st), valued at $7.68 million, an increase from 216 kt (238,000 st), valued at $6.12 million in 2010. Missouri was the leading producing state, followed by Texas, Washington and Ohio, in decreasing order by quantity.

  7. Characterizing regional soil mineral composition using spectroscopyand geostatistics

    USGS Publications Warehouse

    Mulder, V.L.; de Bruin, S.; Weyermann, J.; Kokaly, Raymond F.; Schaepman, M.E.

    2013-01-01

    This work aims at improving the mapping of major mineral variability at regional scale using scale-dependent spatial variability observed in remote sensing data. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and statistical methods were combined with laboratory-based mineral characterization of field samples to create maps of the distributions of clay, mica and carbonate minerals and their abundances. The Material Identification and Characterization Algorithm (MICA) was used to identify the spectrally-dominant minerals in field samples; these results were combined with ASTER data using multinomial logistic regression to map mineral distributions. X-ray diffraction (XRD)was used to quantify mineral composition in field samples. XRD results were combined with ASTER data using multiple linear regression to map mineral abundances. We testedwhether smoothing of the ASTER data to match the scale of variability of the target sample would improve model correlations. Smoothing was donewith Fixed Rank Kriging (FRK) to represent the mediumand long-range spatial variability in the ASTER data. Stronger correlations resulted using the smoothed data compared to results obtained with the original data. Highest model accuracies came from using both medium and long-range scaled ASTER data as input to the statistical models. High correlation coefficients were obtained for the abundances of calcite and mica (R2 = 0.71 and 0.70, respectively). Moderately-high correlation coefficients were found for smectite and kaolinite (R2 = 0.57 and 0.45, respectively). Maps of mineral distributions, obtained by relating ASTER data to MICA analysis of field samples, were found to characterize major soil mineral variability (overall accuracies for mica, smectite and kaolinite were 76%, 89% and 86% respectively). The results of this study suggest that the distributions of minerals and their abundances derived using FRK-smoothed ASTER data more closely match the spatial variability of soil and environmental properties at regional scale.

  8. UTILIZATION OF SOME CERAMIC INDUSTRIAL WASTES FOR MAKING CLAY-BUILDING BRICKS

    Microsoft Academic Search

    N. G. Abd El-Ghafour; H. S. Hassan; H. H. Assal

    The clay deposits at Kom Osheem area, Fayoum Governorate, Egypt, were previously investigated. These clays are silty to silty mud with a mineralogical composition of montmorillonite, montmorillonite - illite, kaolinite and illite clay minerals in addition to, quartz, feldspar and calcite as the non-clay minerals. Chemically, these clays contain low Al2O3, high SiO2 and low soluble salts. The ceramic properties

  9. Compositional variation in clay mineral fraction of fine and coarse-grained units in Westwater Canyon Member (Morrison Formation, San Juan basin, New Mexico)

    Microsoft Academic Search

    P. O. Eberly; L. J. Crossey

    1989-01-01

    Smectites and mixed-layer illite\\/smectite clays from a suite of core samples drawn from the Westwater Canyon Member of the Morrison Formation (USGS borehole S6) have been examined using analytical electron microscopy (AEM) and x-ray diffraction. Samples from 784 and 808 m deep are fine and coarse-grained, respectively. An intermediate sample (806-m depth) is a sandy siltstone with conspicuous shale intraclasts.

  10. Sedimentary and Related Minerals

    NSDL National Science Digital Library

    Dexter Perkins

    In this three-part exercise, students study hand samples and thin sections of sedimentary minerals and rocks. Part one - Box of Rocks: Students examine a tray of Halides, Carbonates, Borates, and Clays and record their physical properties, composition, habit, and occurence. They note chemical and physical similarities and differences of the minerals. Part two - Definitions: Define a list of terms relevent to the lab. Part three - Minerals in Thin Section: Observe sedimentary minerals in thin section and answer questions about them.

  11. Clay energetics in chemical evolution

    NASA Technical Reports Server (NTRS)

    Coyne, L. M.

    1986-01-01

    Clays have been implicated in the origin of terrestrial life since the 1950's. Originally they were considered agents which aid in selecting, concentrating and promoting oligomerization of the organic monomeric substituents of cellular life forms. However, more recently, it has been suggested that minerals, with particular emphasis on clays, may have played a yet more fundamental role. It has been suggested that clays are prototypic life forms in themselves and that they served as a template which directed the self-assembly of cellular life. If the clay-life theory is to have other than conceptual credibility, clays must be shown by experiment to execute the operations of cellular life, not only individually, but also in a sufficiently concerted manner as to produce some semblance of the functional attributes of living cells. Current studies are focussed on the ability of clays to absorb, store and transfer energy under plausible prebiotic conditions and to use this energy to drive chemistry of prebiotic relevance. Conclusions of the work are applicable to the role of clays either as substrates for organic chemistry, or in fueling their own life-mimetic processes.

  12. Ball clay

    USGS Publications Warehouse

    Virta, R.L.

    2012-01-01

    Four companies — H.C. Spinks Clay Co., Inc., Imerys Group, Old Hickory Clay Co., and Unimin Corp. — mined ball clay in four states in 2011. Production, on the basis of preliminary data, was 940 kt (1.04 million st) with an estimated value of $44.2 million. This is a 3-percent increase in tonnage from 912 kt (1.01 million st) with a value of $41.3 million that was produced in 2010. Tennessee was the leading producing state with 63 percent of domestic production, followed by Texas, Mississippi and Kentucky. About 69 percent of production was airfloat, 20 percent was crude and 11 percent was water-slurried.

  13. Clay mineral provinces in tidal mud flats at Germany's North Sea coast with illite K-Ar ages potentially modified by biodegradation

    NASA Astrophysics Data System (ADS)

    Brockamp, Olaf; Clauer, Norbert

    2012-07-01

    Mineralogical studies, chemical analyses and K-Ar dating were carried out on clay fractions from tidal mud flats along the Lower Saxony coast and its bays to identify material sources and sedimentary processes at this dynamic interface between air, land and sea. From the coast into the bays, sediments are enriched in fine-grained smectite relative to the coarser grained illite, chlorite and kaolinite, due to the weakening of the tidal current energy in the bays. In addition, the study area can be divided into two provinces on the basis of the illite K/Rb ratios and Mg contents. To the west [Schiermonnikoog, Dollart, Ley Bay up to Norderney island], longshore currents carry suspensions from the Belgian and Dutch coasts; to the east [from Langeoog island, Jade Bay to the Helgoland mud area] suspensions from the Elbe and Weser rivers are mixed with submarine reworked glacial sediments, whereas the portion of longshore current suspensions from the west decreases, becoming negligible in the Helgoland mud area off the Elbe and Weser estuaries. The illite K-Ar data vary considerably and fail as source indicators due to differential settling and mixing of the clay material and probably to Ar loss from illite by biodegradation during digestive processes. Only further offshore, outside the zone of dynamic sediment dispersion, do the K-Ar data fit provenance patterns.

  14. Modelling of the physico-chemical behaviour of clay minerals with a thermo-kinetic model taking into account particles morphology in compacted material

    Microsoft Academic Search

    D. Sali; B. Fritz; C. Clément; N. Michau

    2003-01-01

    Modelling of fluid-mineral interactions is largely used in Earth Sciences studies to better understand the involved physicochemical processes and their long-term effect on the materials behaviour. Numerical models simplify the processes but try to preserve their main characteristics. Therefore the modelling results strongly depend on the data quality describing initial physicochemical conditions for rock materials, fluids and gases, and on

  15. PII S0016-7037(98)00136-7 The kinetics of mixed Ni-Al hydroxide formation on clay and aluminum oxide minerals

    E-print Network

    Sparks, Donald L.

    . LAMBLE,3 and DONALD L. SPARKS 1 1 Department of Plant and Soil Sciences, University of Delaware, Newark.05 Å increased in all sorption systems, suggesting further growth of a mixed Ni/Al phase from the surface, which depends on the mineral substrate. Using the Ni linear sorption rates observed

  16. Clay for Little Fingers.

    ERIC Educational Resources Information Center

    Koster, Joan Bouza

    1999-01-01

    Discusses the renewed interest in clay as a modeling compound in early childhood programs; describes the nature of clay and presents a working vocabulary. Suggests methods of working with clay, including introducing clay to children, discovering its uses, clean up, firing clay, and finishing baked clay. Includes activity suggestions and…

  17. A granulometry and secondary mineral fingerprint of chemical weathering in periglacial landscapes and its application to blockfield origins

    NASA Astrophysics Data System (ADS)

    Goodfellow, Bradley W.

    2012-12-01

    A review of published literature was undertaken to determine if there was a fingerprint of chemical weathering in regoliths subjected to periglacial conditions during their formation. If present, this fingerprint would be applied to the question of when blockfields in periglacial landscapes were initiated. These blocky diamicts are usually considered to represent remnants of regoliths that were chemically weathered under a warm, Neogene climate and therefore indicate surfaces that have undergone only a few metres to a few 10s of metres of erosion during the Quaternary. Based on a comparison of clay and silt abundances and secondary mineral assemblages from blockfields, other regoliths in periglacial settings, and regoliths from non-periglacial settings, a fingerprint of chemical weathering in periglacial landscapes was identified. A mobile regolith origin under, at least seasonal, periglacial conditions is indicated where clay(%) ? 0.5*silt(%) + 8 across a sample batch. This contrasts with a mobile regolith origin under non-periglacial conditions, which is indicated where clay(%) ? 0.5*silt(%) - 6 across a sample batch with clay(%) ? 0.5*silt(%) + 8 in at least one sample. A range of secondary minerals, which frequently includes interstratified minerals and indicates high local variability in leaching conditions, is also commonly present in regoliths exposed to periglacial conditions during their formation. Clay/silt ratios display a threshold response to temperature, related to the freezing point of water, but there is little response to precipitation or regolith residence time. Lithology controls clay and silt abundances, which increase from felsic, through intermediate, to mafic compositions, but does not control clay/silt ratios. Use of a sedigraph or Coulter Counter to determine regolith granulometry systematically indicates lower clay abundances and intra-site variability than use of a pipette or hydrometer. In contrast to clay/silt ratios, secondary mineral assemblages vary according to regolith residence time, temperature, and/or precipitation. A microsystems model is invoked as a conceptual framework in which to interpret the concurrent formation of the observed secondary mineral ranges. According to the fingerprint of chemical weathering in periglacial landscapes, there is generally no evidence of blockfield origins under warm Neogene climates. Nearly all blockfields appear to be a product of Quaternary physical and chemical weathering. A more dominant role for periglacial processes in further bevelling elevated, low relief, non-glacial surface remnants in otherwise glacially eroded landscapes is therefore indicated.

  18. Sorption of Cm(III) and Eu(III) onto clay minerals under saline conditions: Batch adsorption, laser-fluorescence spectroscopy and modeling

    NASA Astrophysics Data System (ADS)

    Schnurr, Andreas; Marsac, Rémi; Rabung, Thomas; Lützenkirchen, Johannes; Geckeis, Horst

    2015-02-01

    The present work reports experimental data for trivalent metal cation (Cm/Eu) sorption onto illite (Illite du Puy) and montmorillonite (Na-SWy-2) in NaCl solutions up to 4.37 molal (m) in the absence of carbonate. Batch sorption experiments were carried out for a given ionic strength at fixed metal concentration (mEu = 2 × 10-7 m, labeled with 152Eu for ?-counting) and at a constant solid to liquid ratio (S:L = 2 g/L) for 3 < pHm < 12 (pHm = -log mH+). The amount of clay sorbed Eu approaches almost 100% (with log KD > 5) for pHm > 8, irrespective of the NaCl concentration. Variations in Eu uptake are minor at elevated NaCl concentrations. Time-resolved laser fluorescence spectroscopy (TRLFS) studies on Cm sorption covering a wide range of NaCl concentrations reveal nearly identical fluorescence emission spectra after peak deconvolution, i.e. no significant variation of Cm surface speciation with salinity. Beyond the three surface complexes already found in previous studies an additional inner-sphere surface species with a fluorescence peak maximum at higher wavelength (? ? 610 nm) could be resolved. This new surface species appears in the high pH range and is assumed to correspond to a clay/curium/silicate complex as already postulated in the literature for kaolinite. The 2 site protolysis non-electrostatic surface complexation and cation exchange sorption model (2SPNE SC/CE) was applied to describe Eu sorption data by involving the Pitzer and SIT (specific ion interaction) formalism in the calculation of the activities of dissolved aqueous species. Good agreement of model and experiment is achieved for sorption data at pHm < 6 without the need of adjusting surface complexation constants. For pHm > 6 in case of illite and pHm > 8 in case of montmorillonite calculated sorption data systematically fall below experimental data with increasing ionic strength. Under those conditions sorption is almost quantitative and deviations must be discussed considering uncertainties of measured Eu concentrations in the range of analytical detection limits.

  19. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2004-01-01

    Seven companies mined fire clay in four states during 2003. From 1984 to 1992, production declined to 383 kt (422,000 st) from a high of 1.04 Mt (1.14 million st) as markets for clay-based refractories declined. Since 1992, production levels have been erratic, ranging from 383 kt (422,000 st) in 1992 and 2001 to 583 kt (642,000 st) in 1995. Production in 2003, based on preliminary data, was estimated to be around 450 kt (496,000 st) with a value of about $10.5 million. This was about the same as in 2002. Missouri remained the leading producer state, followed by South Carolina, Ohio and California.

  20. Clay Boats

    NSDL National Science Digital Library

    2014-09-18

    Students use a small quantity of modeling clay to make boats that float in a tub of water. The object is to build boats that hold as much weight as possible without sinking. In the process of designing and testing their prototype creations, students discover some of the basic principles of boat design, gain first-hand experience with concepts such as buoyancy and density, and experience the steps of the engineering design process.

  1. Diagenesis and fluid flow in the San Juan Basin, New Mexico - regional zonation in the mineralogy and stable isotope composition of clay minerals in sandstone.

    USGS Publications Warehouse

    Whitney, G.; Northrop, H.R.

    1987-01-01

    The Westwater Canyon Member of the Upper Jurassic Morrison Formation is a relatively homogeneous, hydrologically continuous 100-m-thick sequence of massive fluvial sandstone, bounded above and below by relatively heterogeneous, hydrologically discontinuous units and has served as a primary conduit for fluids within this stratigraphic interval. Patterns of mineral-fluid reactions suggest a basinwide hydrologic regime in which warm, evolved fluids migrated up-dip from the center of the basin under the influence of a regional hydraulic head. -from Authors

  2. INFLUENCE OF AQUEOUS IONIC STRENGTH ON PESTICIDE SORPTION BY SMECTITE CLAY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our recent studies indicated that many agrochemicals demonstrated a great affinity with smectite clays. Exchangeable cations associated with clay minerals significantly influence pesticide sorption by controlling interlayer distance, the size of sorptive domains, and the ability of sorbate functiona...

  3. Effects of low-molecular-weight organic ligands and phosphate on adsorption of Pseudomonas putida by clay minerals and iron oxide.

    PubMed

    Wu, Huayong; Jiang, Daihua; Cai, Peng; Rong, Xingmin; Huang, Qiaoyun

    2011-01-01

    Adsorption of Pseudomonas putida on kaolinite, montmorillonite and goethite was studied in the presence of organic ligands and phosphate. Citrate, tartrate, oxalate and phosphate showed inhibitive effect on P. putida adsorption by three minerals in a broad range of anion concentrations. The highest efficiencies of the four ligands in blocking the adsorption of P. putida on goethite, kaolinite and montmorillonite were 58-90%, 35-76% and 20-48%, respectively. The ability of organic ligands in prohibiting the binding of P. putida cells to the minerals followed the sequence of citrate>tartrate>oxalate>acetate. The significant suppressive effects on P. putida adsorption were ascribed to the increased negative charges by adsorbed ligands and the competition of ligands with bacterial surface groups for binding sites. The inhibitive effects on P. putida adsorption by organic ligands were also dependent on the steric hindrance of the molecules. Acetate presented promotive effect on P. putida adsorption by kaolinite and goethite at low anion concentrations. The results obtained in this study suggested that the adsorption of bacteria in soils especially in the rhizosphere can significantly be impacted by various organic and inorganic anions. PMID:20843669

  4. Studies of radionuclide sorption by clays in the Culebra Dolomite at the WIPP (Waste Isolation Pilot Plant) site, southeastern New Mexico

    SciTech Connect

    Siegel, M.D.; Lawson, R.Z.; Leckie, J.O.; Park, S.W.; Phillips, S.L.; Hale, F.V.; Sewards, T. (Sandia National Labs., Albuquerque, NM (USA); Stanford Univ., CA (USA); Lawrence Berkeley Lab., CA (USA); New Mexico Univ., Albuquerque, NM (USA))

    1990-01-01

    In the most transmissive parts of the Culebra Dolomite, fluid flow is controlled by fractures. Gypsum (CaSO{sub 4} 2H{sub 2}O) and corrensite (a mixed chlorite/smectite) are the most abundant fracture-fill minerals. Radionuclide/clay interactions may be the dominant mechanism for radionuclide retardation. For this reason, the focus of this study is to examine the extent of the sorption of uranium and plutonium onto clays within the Culebra matrix and fractures. This paper describes several coordinated activities which will evaluate the potential retardation of radionuclide migration by sorption onto clays within the Culebras. These include characterization of the compositions of clays and groundwaters along the flow path; studies of the surface properties of simple reference clays and Culebra clays in dilute solutions and saline mixed electrolytes; development of a database of intrinsic equilibrium constants and specific-interaction parameters for calculations of the aqueous speciation of uranium and plutonium in Na-Cl-Ca-SO{sub 4}-CO{sub 3}-EDTA solutions which range in ionic strength from 0.1--4.0 molal; and measurement of surface complexation constants for uranium and plutonium in simple and mixed electrolyte solutions containing clays. 2 refs., 2 figs.

  5. Formation of hydrocarbons from acid-Clay suspensions by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Cruz-Castañeda, J.; Negron-Mendoza, A.; Ramos-Bernal, S.

    2013-07-01

    The adsorption of certain organic compounds by clays gives rise to the transformation of the adsorbate through the action of the clays. This phenomenon can be enhanced using ionizing radiation. In this context, these kinds of reactions play an important role in many natural and industrial processes. For example, in oil and gas exploration, the source and trap of petroleum hydrocarbons is frequently clay-rich rocks. Clay-water-based muds are also seen as environmentally friendly alternatives to toxic oil-based fluids. The principal processes that occur in sediments are usually held to be of bacterial action and thermal transformation, which may include thermally induced catalytic alteration of the organic debris. On the other hand, radioactive materials are widely distributed throughout Earth. They were more abundant in the past, but are present in petroleum reservoirs. Their presence induced radioactive bombardment, which may have altered these sediments. This important subject has not been extensively studied. The aim of this work is to study the behavior of fatty acids—like behenic acid—and dicarboxylic acids—like fumaric acid—as model compounds, which are adsorbed in a clay mineral (Na-montmorillonite) and exposed to gamma radiation. The results show that the radiation-induced decomposition of the clay-acid system goes along a definitive path (oxidation), rather than following several modes of simultaneous decomposition, as happens in radiolysis without clay or by heating the system. The main radiolytic products for fatty acids are their corresponding hydrocarbons, with one C-atom less than the original acid.

  6. 2007 Minerals Yearbook U.S. Department of the Interior

    E-print Network

    2007 Minerals Yearbook U.S. Department of the Interior U.S. Geological Survey CLAY AND SHALE May (23%), foundry sand bond (17%), and iron ore pelletizing (14%); for common clay and shale, brick (57%), portland cement (19%), and lightweight aggregate (14%); for fire clay, heavy clay products and lightweight

  7. Clay: The Forgotten Art.

    ERIC Educational Resources Information Center

    Martin, Doris Marie

    1995-01-01

    Discusses the tactile and kinesthetic areas of learning children experience when using clay. Includes practical tips for using and storing clay for preschool use and notes the differences between potters' clay and play dough. (HTH)

  8. Structure-related geochemical (REE) and isotopic (K-Ar, Rb-Sr, ? 18O) characteristics of clay minerals from Rotliegend sandstone reservoirs (Permian, northern Germany)

    NASA Astrophysics Data System (ADS)

    Zwingmann, Horst; Clauer, Norbert; Gaupp, Reinhard

    1999-09-01

    Euhedral illite cementing the gas-bearing sandstone reservoirs of the Rotliegend in the Niedersächsische rift system (northern Germany) was studied along a horst-to-graben cross-section to examine its chemical and isotopic characteristics. The data show that differentiated illite particles grew during a tectono-thermal event marked by distinct episodic hydrothermal activities along fault drains and in the poral space of sandstones at 210 Ma and at 195 to 190 Ma in horst positions, at 185 to 175 Ma in the nearby graben, and at 170 to 165 Ma in both the horst and graben. Varied REE distribution patterns and initial 87Sr/ 86Sr ratios (from 0.7124 to 0.7142) relative to illite-particle size outline a high chemical variability of the fluids during illite growth. The ? 18O values of illite range from +20.0 to +12.4‰ and those of chlorite from +12.0 to +6.9‰. The changing ? 18O values of the minerals most likely relate to varied ? 18O values of the fluids, or to different water/rock ratios during crystallization. Differences among the REE and 87Sr/ 86Sr tracers and the ? 18O values of different generations of illite also suggest a changing fluid chemistry relative to time. Significant positive Eu anomalies and negative Ce anomalies in the REE distributions of illite suggest feldspar alteration by the migrating fluids in oxidizing environments.

  9. CLAY AND SHALE--2003 18.1 CLAY AND SHALE

    E-print Network

    CLAY AND SHALE--2003 18.1 CLAY AND SHALE By Robert L. Virta Domestic survey data and tables were of clays--ball clay, bentonite, common clay and shale, fire clay, fuller's earth, and kaolin. Ball clays amounts of biotite, feldspars, and quartz. Common clay and shale contain chlorite and illite as major

  10. Clay microporosity in reservoir sandstones: An application of quantitative electron microscopy in petrophysical evaluation

    SciTech Connect

    Hurst, A. [Univ. of Aberdeen (United Kingdom); Nadeau, P.H. [Statoil, Forus (Norway)

    1995-04-01

    Clay mineral microporosity in sandstones is measured using computer-assisted image analysis of back-scattered electron micrographs of petrographic sections. Diagenetic kaolinite has a variety of textures with microporosity values ranging from 15 to 61%. Diagenetic chlorite has a generally uniform grain-coating texture and microporosity of about 50%. Fibrous illitic clays are difficult to characterize by the same method (an average value of 63% microporosity was recorded), but analysis of stereo-pair micrographs from scanning-electron microscopy analyses reveals that illite commonly has microporosity of approximately 90%. Clay microporosity data are used to calculate effective pore volumes and volumes of clay-bound water for clay minerals in sandstones. Converting from weight percent clay to volume percent clay is important. Microporosity data are valuable input to V{sub shale} evaluation where water saturation is associated with clay mineral type, texture, and volume.

  11. Carboxylic acid sorption on synthetic clays in marine water: in vitro experiments and implications for organo-clay behaviour under marine conditions

    E-print Network

    1 Carboxylic acid sorption on synthetic clays in marine water: in vitro experiments and implications for organo-clay behaviour under marine conditions Sylvain Drouin a , Mohammed Boussafir a* , Jean to investigate the role of clay minerals in organic matter preservation, the fixation of pure organic compounds

  12. Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol : the significance of soluble material

    E-print Network

    Garimella, Sarvesh

    2014-01-01

    This study examines the interaction of clay mineral particles and water vapor to determine the conditions required for cloud droplet formation. Droplet formation conditions are investigated for two common clay minerals, ...

  13. Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material

    E-print Network

    Garimella, Sarvesh

    This study examines the interaction of clay mineral particles and water vapor for determining the conditions required for cloud droplet formation. Droplet formation conditions are investigated for two common clay minerals, ...

  14. 173. NICKEL SORPTION KINETICS ON THE CLAY FRACTION OF A SOIL. D.R. Roberts and D.L. Sparks, Department of Plant and Soil Sciences, University of Delaware, Newark,

    E-print Network

    Sparks, Donald L.

    173. NICKEL SORPTION KINETICS ON THE CLAY FRACTION OF A SOIL. D.R. Roberts and D.L. Sparks on the release of Ni(II) from the clay fraction. Ascertaining the kinetics of nickel sorption on clay minerals

  15. Computer simulation of interlayer water in 2:1 clays

    Microsoft Academic Search

    N. T. Skipper; K. Refson; J. D. C. McConnell

    1991-01-01

    Monte Carlo computer simulation has been used to study water confined between the layers of 2:1 clay minerals. The model systems are based on natural Mg and Na smectites. The simulation cells contain one clay layer, 64 water molecules and four magnesium or eight sodium interlayer cations. These atoms and molecules interact with each other through a new set of

  16. Effects of provenance on clay diagenesis and porosity in upper Wilcox Formation

    SciTech Connect

    Strickler, M.E.; Ferrell, R.E. Jr.

    1989-03-01

    The provenance of sediments in the lower Eocene upper Wilcox Group in southeastern Louisiana was studied in 16 conventional cores from the Lockhart Crossing field by using optical, x-ray diffraction, and electron microprobe methods. Detrital clays were a mixture of highly illitic degraded micas, degraded chlorites, and minor kaolinite derived from the weathered metamorphic, plutonic, and sedimentary rocks of the region. The abundance of gneissic, granitic, and metasedimentary rock fragments, detrital IIb chlorites, 1M and 2M micas, and the iron, magnesium, and aluminum ratios of chlorites and muscovites also support the provenance interpretation. Clay diagenesis in the southeast Louisiana Wilcox differs from the typical smectite-illite sequence reported from the western Gulf of Mexico. The montmorillonite (derived from volcanics) deposited in the Wilcox of southwestern Texas was very unstable at greater burial depths and temperatures and reacted to form illite. This reaction in turn provided cations for cements and authigenic clays that usually have detrimental effects on permeability. Early carbonate cementation and later dissolution of these cements are the most important events affecting porosity and permeability in the Wilcox of the Lockhart Crossing field. Diagenetic kaolinite, which formed at the expense of feldspars, rock fragments, and detrital clays, has had little effect on permeability unless redistributed. Iron-rich glauconites and chlorites could potentially be detrimental to porosity and permeability during acidization. In general, clay diagenesis has had only minor harmful effects on the porosity and permeabilities of the Wilcox in the eastern Gulf of Mexico basin, and provenance rather than diagenesis has been more important in determining the present clay mineral assemblage.

  17. Factors Affecting Clay Formation

    Microsoft Academic Search

    Isaac Barshad

    1957-01-01

    Barshad's method of calculating clay formation from the chemical analyses of the whole soil, the clay fraction, the nonclay fraction, and the mechanical analysis was applied to a large number of soils to determine the effect of climate, topography, parent material, vegetation and time on al~ount of clay formation. The amount of clay formed from )00 g of the nonclay

  18. Herbivore trampling as an alternative pathway for explaining differences in nitrogen mineralization in moist grasslands.

    PubMed

    Schrama, Maarten; Heijning, Pieter; Bakker, Jan P; van Wijnen, Harm J; Berg, Matty P; Olff, Han

    2013-05-01

    Studies addressing the role of large herbivores on nitrogen cycling in grasslands have suggested that the direction of effects depends on soil fertility. Via selection for high quality plant species and input of dung and urine, large herbivores have been shown to speed up nitrogen cycling in fertile grassland soils while slowing down nitrogen cycling in unfertile soils. However, recent studies show that large herbivores can reduce nitrogen mineralization in some temperate fertile soils, but not in others. To explain this, we hypothesize that large herbivores can reduce nitrogen mineralization in loamy or clay soils through soil compaction, but not in sandy soils. Especially under wet conditions, strong compaction in clay soils can lead to periods of soil anoxia, which reduces decomposition of soil organic matter and, hence, N mineralization. In this study, we use a long-term (37-year) field experiment on a salt marsh to investigate the hypothesis that the effect of large herbivores on nitrogen mineralization depends on soil texture. Our results confirm that the presence of large herbivores decreased nitrogen mineralization rate in a clay soil, but not in a sandy soil. By comparing a hand-mown treatment with a herbivore-grazed treatment, we show that these differences can be attributed to herbivore-induced changes in soil physical properties rather than to above-ground biomass removal. On clay soil, we find that large herbivores increase the soil water-filled porosity, induce more negative soil redox potentials, reduce soil macrofauna abundance, and reduce decomposition activity. On sandy soil, we observe no changes in these variables in response to grazing. We conclude that effects of large herbivores on nitrogen mineralization cannot be understood without taking soil texture, soil moisture, and feedbacks through soil macrofauna into account. PMID:23271034

  19. Chemical reactions of organic compounds on clay surfaces.

    PubMed Central

    Soma, Y; Soma, M

    1989-01-01

    Chemical reactions of organic compounds including pesticides at the interlayer and exterior surfaces of clay minerals and with soil organic matter are reviewed. Representative reactions under moderate conditions possibly occurring in natural soils are described. Attempts have been made to clarify the importance of the chemical nature of molecules, their structures and their functional groups, and the Brönsted or Lewis acidity of clay minerals. PMID:2533556

  20. Phosphates in some missouri refractory clays

    USGS Publications Warehouse

    Hall, R.B.; Foord, E.E.; Keller, D.J.; Keller, W.D.

    1997-01-01

    This paper describes in detail phosphate minerals occurring in refractory clays of Missouri and their effect on the refractory degree of the clays. The minerals identified include carbonate-fluorapatite (francolite), crandallite, goyazite, wavellite, variscite and strengite. It is emphasized that these phosphates occur only in local isolated concentrations, and not generally in Missouri refractory clays. The Missouri fireclay region comprises 2 districts, northern and southern, separated by the Missouri River In this region, clay constitutes a major part of the Lower Pennsylvanian Cheltenham Formation. The original Cheltenham mud was an argillic residue derived from leaching and dissolution of pre-Pennsylvanian carbonates. The mud accumulated on a karstic erosion surface truncating the pre-Cheltenham rocks. Fireclays of the northern district consist mainly of poorly ordered kaolinite, with variable but minor amounts of illite, chlorite and fine-grained detrital quartz. Clays of the southern district were subjected to extreme leaching that produced well-ordered kaolinite flint clays. Local desilication formed pockets of diaspora, or more commonly, kaolinite, with oolite-like nubs or burls of diaspore ("burley" clay). The phosphate-bearing materials have been studied by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectral analysis (SEM-EDS) and chemical analysis. Calcian goyazite was identified in a sample of diaspore, and francolite in a sample of flint clay. A veinlet of wavellite occurs in flint clay at one locality, and a veinlet of variscite-strengite at another locality. The Missouri flint-clay-hosted francolite could not have formed in the same manner as marine francolite The evidence suggests that the Cheltenham francolite precipitated from ion complexes in pore water nearly simultaneously with crystallization of kaolinite flint clay from an alumina-silica gel. Calcian goyazite is an early diagenetic addition to its diaspore host. The wavellite and variscite-strengite veinlets are secondary, precipitated from ion complexes in ground water percolating along cracks in the flint clay. The flint clay host of the variscite-strengite veinlet contains strontian crandallite. All of the phosphates contain significant amounts of strontium. The source of P, Ca and Sr was the marine carbonates. Dissolution of these carbonates produced the argillic residue that became the primordial Cheltenham paludal mud, which ultimately altered to fireclay. Preliminary firing tests show that the presence of phosphates lowers fusion temperature. However, it is not clear whether poor refractoriness is due to the presence of phosphates, per se, or to Ca, Sr and other alkaline elements present in the phosphates.

  1. CLAY AND SHALE--2002 18.1 CLAY AND SHALE

    E-print Network

    CLAY AND SHALE--2002 18.1 CLAY AND SHALE By Robert L. Virta Domestic survey data and tables were Roberts, international data coordinator. Companies in the United States mined six types of clays: ball clay, bentonite, common clay and shale, fire clay, fuller's earth, and kaolin. Ball clays consist

  2. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2011-01-01

    The article discusses the latest developments in the global common clay and shale industry, particularly in the U.S. It claims that common clay and shale is mainly used in the manufacture of heavy clay products like brick, flue tile and sewer pipe. The main producing states in the U.S. include North Carolina, New York and Oklahoma. Among the firms that manufacture clay and shale-based products are Mid America Brick & Structural Clay Products LLC and Boral USA.

  3. The Nature of Excess Intercalation of a Quaternary Ammonium Compound in Smectite Clay

    Microsoft Academic Search

    D. A. Lafer; R. Giese

    2010-01-01

    Particular clay minerals, such as the French green clay used by Brunet de Courssou in the treatment of Mycobacterium ulcerans, have intrinsic antibacterial properties that surpass those of most conventional antibiotic treatments. The antimicrobial properties of the French green clay, comprised of 24% Fe-illite and 50% Fe-smectite, have been reproduced by a synthetically generated organically modified smectite (organoclay). The quaternary

  4. Effects of calcination temperature of kaolinite clays on the properties of geopolymer cements

    Microsoft Academic Search

    A. Elimbi; H. K. Tchakoute; D. Njopwouo

    2011-01-01

    The aim of this work is to determine the most convenient calcination temperature of kaolinite clays in view of producing geopolymer cements. In this light, the clay fractions of three kaolin minerals were used. The clay fractions were characterized (chemical and thermal analyses and X-ray diffraction) and then calcined in the temperature range of 450 and 800°C. The obtained amorphous

  5. The role of charcoal on DTA curves of organo-clay complexes: an overview

    Microsoft Academic Search

    Shmuel Yariv

    2004-01-01

    DTA of organo-clay complexes supplemented by other thermal analysis methods supplies information on the thermal reactions, properties and stability of the complex, the amount and properties of the adsorbed water in the organo-clay and on the bonding between the organic species and the clay. It is used to identify the mineral to differentiate between various complexes composed of the same

  6. Sulphate attack and ettringite formation in the lime and cement stabilized marine clays

    Microsoft Academic Search

    G. Rajasekaran

    2005-01-01

    Swelling and shrinkage behaviour of marine clays impose foundation problems that may sometimes results in excessive settlements. Improving the behaviour of soft clays using lime or cement is not new. Recent studies reported the occurrence of high swelling and pavement failures in lime and cement stabilized clays containing sulphates. The above phenomena resulted in the formation of swelling minerals such

  7. Evidence for Smectite Clays from MSL SAM Analyses of Mudstone at Yellowknife Bay, Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    McAdam, A.; Franz, H.; Mahaffy, P. R.; Eigenbrode, J. L.; Stern, J. C.; Brunner, A.; Sutter, B.; Archer, P. D.; Ming, D. W.; Morris, R. V.; Atreya, S. K.; Team, M.

    2013-12-01

    Drilled samples of mudstone from the Sheepbed unit at Yellowknife Bay were analyzed by MSL instruments including the Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments in MSL's Analytical Laboratory. CheMin analyses revealed the first in situ X-ray diffraction based evidence of clay minerals on Mars, which are likely trioctahedral smectites (e.g., saponite) and comprise ~20% of the mudstone sample (e.g., Bristow et al., this meeting). SAM analyses, which heated the mudstone samples to 1000oC and monitored volatiles evolved to perform in situ evolved gas analysis mass spectrometry (EGA-MS), resulted in a H2O trace exhibiting a wide evolution at temperatures <500oC, and an evolution peak at higher temperatures near ~750oC. The low temperature H2O evolution has many potential contributors, including adsorbed H2O, smectite interlayer H2O, and structural H2O/OH from bassanite and akaganeite (identified by CheMin) and H2O/OH from amorphous phases in the sample. The high temperature H2O is consistent with the evolution of H2O from the dehydroxylation of the smectite clay mineral. Comparison to EGA-MS data collected under SAM-like conditions on a variety of clay mineral reference materials indicate that a trioctahedral smectite, such as saponite, is most consistent with the high temperature H2O evolution observed. There may also be SAM EGA-MS evidence for a small high temperature H2O evolution from scoop samples from the Yellowknife Bay Rocknest sand shadow bedform. As in the mudstone samples, this evolution may indicate the detection of smectite clays, and the idea that minor clays may be present in Rocknest materials that could be expected to be at least partially derived from local sources is reasonable. But, because smectite clays were not definitively observed in CheMin analyses of Rocknest materials, they must be present at much lower abundances than the ~20% observed in the mudstone samples. This potential detection underscores the complementary nature of the MSL CheMin and SAM instruments for investigations of martian sample mineralogy. Information on the nature of Yellowknife Bay clay minerals may also be available from the detection of H2 evolved during SAM EGA-MS at high temperature. A likely source of at least some of this H2 is H2O evolved from the smectite clays at high temperature, and it is possible these evolutions can be used in a similar fashion to high temperature H2O releases to provide constraints on the clay minerals in a sample. In addition, the D/H of this high temperature H2, as well as the H2O, can be derived from SAM MS and Tunable Laser Spectrometer (TLS) data, respectively. These D/H values may help to inform the provenance of high and low temperature water evolved from martian samples (Mahaffy et al., this meeting).

  8. Mineral Commodities

    NSDL National Science Digital Library

    Dexter Perkins

    This exercise introduces mineral commodities (elements). Students consider the elements aluminum, iron, copper, nickel, zinc, uranium, lead, gold, mercury and tin and match them with their definintions in a table. Then they use minable grade (minable weight percent) and normal crustal abundance (crustal weight percent) to calculate the concentration factor for several commodities to determine their economic minability. Students then graph their calculations and explain their trend.

  9. Natural Radioactivity of Boron Added Clay Samples

    NASA Astrophysics Data System (ADS)

    Akkurt, I.; ?anakci?, H.; Mavi, B.; Güno?lu, K.

    2011-12-01

    Clay, consisting fine-grained minerals, is an interesting materials and can be used in a variety of diferent fields especially in dermatology application. Using clay such a field it is important to measure its natural radioacitivty. Thus the purpose of this study is to measure 226Ra, 232Th and 40K concentration in clay samples enriched with boron. Three different types of clay samples were prepared where boron is used in different rate. The measurements have been determined using a gamma-ray spectrometry consists of a 3?×3? NaI(Tl) detector. From the measured activity the radium equivalent activities (Raeq), external hazard index (Hex), absorbed dose rate in air (D) and annual effective dose (AED) have also been obtained.

  10. Prolonged triboluminescence in clays and other minerals

    NASA Technical Reports Server (NTRS)

    Lahav, N.; Coyne, L. M.; Lawless, J. G.

    1982-01-01

    The decay curves of various triboluminescent-excited materials were obtained, including well-crystallized and poorly crystallized kaolin, bentonite, quartz, sodium chloride, and chalk calcite. A qualitative increase in triboluminescence was observed for kaolin dipped in water or tryptophan solution compared to dry kaolin, and for frozen kaolin and montmorillonite pastes. Theoretical explanations for the tryptophan effect are discussed.

  11. Silt-clay aggregates on Mars

    Microsoft Academic Search

    Ronald Greeley

    1979-01-01

    Viking observations suggest abundant silt and clay particles on Mars. It is proposed that some of these particles agglomerate to form sand size aggregates that are redeposited as sandlike features such as drifts and dunes. Although the binding for the aggregates could include salt cementation or other mechanisms, electrostatic bonding is considered to be a primary force holding the aggregates

  12. Communicating with Clay.

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2000-01-01

    Presents a unit on clay that is centered around sign language in which students explore the slab method of working with clay. States that each student picks a letter of the sign language alphabet and fashions a clay hand to depict the letter. (CMK)

  13. Geosynthetic clay liner applications

    Microsoft Academic Search

    L. T. McGrath; P. D. Creamer

    1995-01-01

    Geosynthetic clay liners (GCLs) are becoming a popular alternative to compacted clay barrier layers at sanitary landfills. They possess many of the same qualities of compacted clay barrier layers while occupying only a small fraction of the airspace. This is a very attractive feature to waste disposal facility owners and operators. Designing for, and constructing with, a GCL can be

  14. Iodide Sorption to Clays and the Relationship to Surface Charge and Clay Texture - 12356

    SciTech Connect

    Miller, Andrew; Kruichiak, Jessica; Tellez, Hernesto; Wang, Yifeng [Sandia National Laboratories, Albuquerque, NM 87185 (United States)

    2012-07-01

    Iodine is assumed to behave conservatively in clay barriers around nuclear waste repositories and in natural sediments. Batch experiments tend to show little to no sorption, while in column experiments iodine is often retarded relative to tritiated water. Current surface complexation theory cannot account for negatively charged ion sorption to a negatively charged clay particle. Surface protonation and iodide sorption to clay minerals were examined using surface titrations and batch sorption experiments with a suite of clay minerals. Surface titrations were completed spanning a range of both pH values and ionic strengths. For reference, similar titrations were performed on pure forms of an Al-O powder. The titration curves were deconvoluted to attain the pKa distribution for each material at each ionic strength. The pKa distribution for the Al-O shows two distinct peaks at 4.8 and 7.5, which are invariant with ionic strength. The pKa distribution of clays was highly variable between the different minerals and as a function of ionic strength. Iodide sorption experiments were completed at high solid:solution ratios to exacerbate sorption properties. Palygorskite and kaolinite had the highest amount of iodide sorption and montmorillonite had the least. (authors)

  15. The role of reaction affinity and secondary minerals in regulating chemical weathering rates at the Santa Cruz Soil Chronosequence, California

    USGS Publications Warehouse

    Maher, K.; Steefel, Carl; White, A.F.; Stonestrom, D.A.

    2009-01-01

    In order to explore the reasons for the apparent discrepancy between laboratory and field weathering rates and to determine the extent to which weathering rates are controlled by the approach to thermodynamic equilibrium, secondary mineral precipitation, and flow rates, a multicomponent reactive transport model (CrunchFlow) was used to interpret soil profile development and mineral precipitation and dissolution rates at the 226 ka Marine Terrace Chronosequence near Santa Cruz, CA. Aqueous compositions, fluid chemistry, transport, and mineral abundances are well characterized [White A. F., Schulz M. S., Vivit D. V., Blum A., Stonestrom D. A. and Anderson S. P. (2008) Chemical weathering of a Marine Terrace Chronosequence, Santa Cruz, California. I: interpreting the long-term controls on chemical weathering based on spatial and temporal element and mineral distributions. Geochim. Cosmochim. Acta 72 (1), 36-68] and were used to constrain the reaction rates for the weathering and precipitating minerals in the reactive transport modeling. When primary mineral weathering rates are calculated with either of two experimentally determined rate constants, the nonlinear, parallel rate law formulation of Hellmann and Tisserand [Hellmann R. and Tisserand D. (2006) Dissolution kinetics as a function of the Gibbs free energy of reaction: An experimental study based on albite feldspar. Geochim. Cosmochim. Acta 70 (2), 364-383] or the aluminum inhibition model proposed by Oelkers et al. [Oelkers E. H., Schott J. and Devidal J. L. (1994) The effect of aluminum, pH, and chemical affinity on the rates of aluminosilicate dissolution reactions. Geochim. Cosmochim. Acta 58 (9), 2011-2024], modeling results are consistent with field-scale observations when independently constrained clay precipitation rates are accounted for. Experimental and field rates, therefore, can be reconciled at the Santa Cruz site. Additionally, observed maximum clay abundances in the argillic horizons occur at the depth and time where the reaction fronts of the primary minerals overlap. The modeling indicates that the argillic horizon at Santa Cruz can be explained almost entirely by weathering of primary minerals and in situ clay precipitation accompanied by undersaturation of kaolinite at the top of the profile. The rate constant for kaolinite precipitation was also determined based on model simulations of mineral abundances and dissolved Al, SiO2(aq) and pH in pore waters. Changes in the rate of kaolinite precipitation or the flow rate do not affect the gradient of the primary mineral weathering profiles, but instead control the rate of propagation of the primary mineral weathering fronts and thus total mass removed from the weathering profile. Our analysis suggests that secondary clay precipitation is as important as aqueous transport in governing the amount of dissolution that occurs within a profile because clay minerals exert a strong control over the reaction affinity of the dissolving primary minerals. The modeling also indicates that the weathering advance rate and the total mass of mineral dissolved is controlled by the thermodynamic saturation of the primary dissolving phases plagioclase and K-feldspar, as is evident from the difference in propagation rates of the reaction fronts for the two minerals despite their very similar kinetic rate laws. ?? 2009 Elsevier Ltd.

  16. Soil clay content underlies prion infection odds

    USGS Publications Warehouse

    David, Walter W.; Walsh, D.P.; Farnsworth, Matthew L.; Winkelman, D.L.; Miller, M.W.

    2011-01-01

    Environmental factors-especially soil properties-have been suggested as potentially important in the transmission of infectious prion diseases. Because binding to montmorillonite (an aluminosilicate clay mineral) or clay-enriched soils had been shown to enhance experimental prion transmissibility, we hypothesized that prion transmission among mule deer might also be enhanced in ranges with relatively high soil clay content. In this study, we report apparent influences of soil clay content on the odds of prion infection in free-ranging deer. Analysis of data from prion-infected deer herds in northern Colorado, USA, revealed that a 1% increase in the clay-sized particle content in soils within the approximate home range of an individual deer increased its odds of infection by up to 8.9%. Our findings suggest that soil clay content and related environmental properties deserve greater attention in assessing risks of prion disease outbreaks and prospects for their control in both natural and production settings. ?? 2011 Macmillan Publishers Limited. All rights reserved.

  17. Clays in prebiological chemistry

    NASA Technical Reports Server (NTRS)

    Rao, M.; Oro, J.; Odom, D. G.

    1980-01-01

    The ways in which clays have been utilized in studies of prebiological chemistry are reviewed, and an assessment is given of the possible role of clays in prebiological systems. The adsorption of organic molecules on clays has been demonstrated, as has the synthesis of bioorganic monomers in the presence of clays. For instance, amino acids, purines and pyrimidines have been obtained from carbon monoxide and nitric acid in the presence of clays at relatively high temperatures (250-325 C). The oligomerization of biochemical monomers, mediated by clays, has also been shown to result in the formation of polymer molecules basic to life. Clays have also been found to affect the condensation of mononucleotides to oligonucleotides.

  18. Molecular-level analysis of organic matter structure and composition from different soil mineral fractions

    NASA Astrophysics Data System (ADS)

    Clemente, J. S.; Gregorich, E. G.; Simpson, A. J.; Simpson, M. J.

    2009-04-01

    The formation and turnover of soil organic matter (SOM) depends on the inherent chemical characteristics of biomolecular inputs (lignin, proteins, carbohydrates, macromolecular lipids, etc.) as well as the interactions between biomolecules and soil mineral fractions. The objective of this study is to characterize organic matter associated with the light, sand, silt and clay fractions of a Canadian agricultural soil. And, because lignin is believed to be a major contributor in SOM formation and preservation, the oxidation state of lignin in the different mineral fractions was measured using mild alkaline copper oxidation and gas chromatography - mass spectrometery which releases lignin phenols that are indicative of lignin sources and stage of degradation. For example, an increase in the acid/aldehyde (Ad/Al) ratio of lignin phenols has been observed with increased lignin degradation (and oxidation). In this study, lignin phenols from organic matter associated with the clay fraction had higher Ad/Al ratios for both syringyl and vanillyl lignin monomers when compared to that associated with silt, sand and the whole soil. These results suggest that either lignin degradation is enhanced by SOM association with clay surfaces or that oxidized lignin is preserved on clay mineral surfaces via sorption after partial degradation has occurred. The structural characteristics of organic matter from the soil fractions will also be examined by solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Organic matter associated with each mineral fraction will be extracted with NaOH for high resolution solution-state NMR spectroscopy. Results from NMR analysis will determine the relative abundance of functional groups (alkane, aromatic, carbonyl, alkoxy) in each of the soil fractions. Relative intensities of the functional groups are indicative of relative contributions of biomolecular classes such as lipids, lignin, fatty acids, and sugars to the organic matter associated with each fraction. The study comprises our initial steps in characterizing protection mechanisms responsible for the long-term retention and stability of biomolecules and their degradation intermediates in soil.

  19. Molecular-Level Analysis of Organic Matter Structure and Composition from Different Soil Mineral Fractions

    NASA Astrophysics Data System (ADS)

    Clemente, J. S.; Gregorich, E. G.; Simpson, A. J.; Simpson, M. J.

    2009-05-01

    The formation and turnover of soil organic matter (SOM) depends on the inherent chemical characteristics of biomolecular inputs (lignin, proteins, carbohydrates, macromolecular lipids, etc.) as well as the interactions between biomolecules and soil mineral fractions. The objective of this study is to characterize organic matter associated with the light, sand, silt and clay fractions of a Canadian agricultural soil. And, because lignin is believed to be a major contributor in SOM formation and preservation, the oxidation state of lignin in the different mineral fractions was measured using mild alkaline copper oxidation and gas chromatography - mass spectrometery which releases lignin phenols that are indicative of lignin sources and stage of degradation. For example, an increase in the acid/aldehyde (Ad/Al) ratio of lignin phenols has been observed with increased lignin degradation (and oxidation). In this study, lignin phenols from organic matter associated with the clay fraction had higher Ad/Al ratios for both syringyl and vanillyl lignin monomers when compared to that associated with silt, sand and the whole soil. These results suggest that either lignin degradation is enhanced by SOM association with clay surfaces or that oxidized lignin is preserved on clay mineral surfaces via sorption after partial degradation has occurred. The structural characteristics of organic matter from the soil fractions will also be examined by solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Organic matter associated with each mineral fraction will be extracted with NaOH for high resolution solution-state NMR spectroscopy. Results from NMR analysis will determine the relative abundance of functional groups (alkane, aromatic, carbonyl, alkoxy) in each of the soil fractions. Relative intensities of the functional groups are indicative of relative contributions of biomolecular classes such as lipids, lignin, fatty acids, and sugars to the organic matter associated with each fraction. The study comprises our initial steps in characterizing protection mechanisms responsible for the long-term retention and stability of biomolecules and their degradation intermediates in soil.

  20. Cytotoxicity and mutagenicity assessment of organomodified clays potentially used in food packaging.

    PubMed

    Maisanaba, Sara; Prieto, Ana I; Pichardo, Silvia; Jordá-Beneyto, María; Aucejo, Susana; Jos, Ángeles

    2015-09-01

    Modern food packaging has made great advances as result of global trends and consumer preferences, which are oriented to obtain improved food quality and safety. In this regard, clay minerals, and mainly Montmorillonite (Mt) are attracting considerable interest in food packaging because of the improvements developed in mechanical and barrier properties. Hence, the present work aim to assess the toxicity of four Montmorillonite-based clay minerals, an unmodified clay, Cloisite®Na+ (CNa+), and three modified Mt clays: Cloisite®30B (C30B), a commercial clay, and Clay1 and Clay2, two novel modified organoclays developed by the Packaging, Transport, & Logistics Research Institute (ITENE). First, the cytotoxic effects were studied in the Human Umbilical Vein Endothelial Cells (HUVEC). In addition, the potential mutagenicity of the clays was evaluated by the Ames test. Clay1 did not induce any cytotoxic effects in HUVEC, although it exhibited potential mutagenicity in TA98 Salmonella typhimurium strain. In contrast, Clay2 produced cytotoxicity in endothelial cells but no mutagenicity was recorded. However, CNa+ was not cytotoxic neither mutagenic. And finally, C30B showed positive results in both assays. Therefore, results showed that clay minerals have a different toxicity profile and a case by case toxicity evaluation is required. PMID:25820134

  1. CLAY AND SHALE--1999 18.1 CLAY AND SHALE

    E-print Network

    CLAY AND SHALE--1999 18.1 CLAY AND SHALE By Robert L. Virta Domestic survey data and tables were Roberts, international data coordinator. The amount of clay sold or used by domestic producers in 1999. Production of ball clay, bentonite, common clay and shale, and fuller's earth increased, and production

  2. Ni Sorption/Release on Soil Clay Fractions A Kinetic and EXAFS Study D. R. Roberts, and A. M. Scheidegger

    E-print Network

    Sparks, Donald L.

    Ni Sorption/Release on Soil Clay Fractions A Kinetic and EXAFS Study D. R. Roberts, and A. M in soils have often been studied on standard clay minerals and metal oxides while using a macroscopic/kinetics of Ni (II) on the well characterized clay fraction (

  3. Clay mineralogy of surface sediments as a tool for deciphering river contributions to the Cariaco Basin (Venezuela)

    E-print Network

    Meyers, Steven D.

    Clay mineralogy of surface sediments as a tool for deciphering river contributions to the Cariaco the Cariaco Basin continental shelf and Orinoco delta was investigated in order to constrain the clay was studied using a geo-statistical approach that allows drawing representative clay-mineral distribution maps

  4. Comparison of abundances of chemical elements in mineralized and unmineralized sandstone of the Brushy Basin Member of the Morrison Formation, Smith Lake District, Grants uranium region, New Mexico

    USGS Publications Warehouse

    Pierson, C.T.; Spirakis, C.S.; Robertson, J.F.

    1983-01-01

    Statistical treatment of analytical data from the Mariano Lake and Ruby uranium deposits in the Smith Lake district, New Mexico, indicates that organic carbon, arsenic, barium, calcium, cobalt, copper, gallium, iron, lead, manganese, molybdenum, nickel, selenium, strontium, sulfur, vanadium, yttrium, and zirconium are concentrated along with uranium in primary ore. Comparison of the Smith Lake data with information from other primary deposits in the Grants uranium region and elsewhere in the Morrison Formation of the Colorado Plateau suggests that these elements, with the possible exceptions of zirconium and gallium and with the probable addition of aluminum and magnesium, are typically associated with primary, tabular uranium deposits. Chemical differences between the Ruby and Mariano Lake deposits are consistent with the interpretation that the Ruby deposit has been more affected by post-mineralization oxidizing solutions than has the Mariano Lake deposit.

  5. Polymer-Clay Nanocomposites

    Microsoft Academic Search

    Arimitsu Usuki; Naoki Hasegawa; Makoto Kato; Shiro Kobayashi

    The development of polymer-clay nanocomposite materials, in which nanometer-thick layers of clay are dispersed in polymers, was first achieved about 15 years ago. Since then, the materials have gradually become more widely used in applications such as automotive production. The first practical nylon-clay nanocomposite was synthesized by a monomer intercalation technique; however, the production process has been further developed and a compound

  6. Flow of clays

    NASA Astrophysics Data System (ADS)

    Fossum, J. O.

    2012-04-01

    Recent experimental and theoretical research into physical phenomena in clays is reviewed. Clays' present place in the context of modern materials science is briefly discussed, and illustrated through the rich behavior recently displayed in this physical model system. We will show that in order to understand macroscopic flow behaviors in these systems, it is crucial to know the underlying nanostructures in detail. With the clay nanostructural basis at hand, we will review recent advances in clay systems from the geological example of quick clay flows and avalanches, to materials science and the stability, strength and flow of smart electrorheological clay structures. In the case of natural quick clay, there is now hope of establishing a protocol for avalanche preditction based on rheological sample data. In materials science, the use of electric fields together with flow in order to improve the processing of clay composite materials may open new unexplored avenues. We will finally discuss that due to the interplay of van der Waals and electrostatic forces screened by ions at the nanoscale, clays may either form a glass, or a gel and thus give fundamental insights into the elusive questions related to materials universal aging flow dynamics.

  7. Geochemical effects of electro-osmosis in clays

    Microsoft Academic Search

    J. P. Gustav LochAna; Ana Teresa Lima; Pieter J. Kleingeld

    2010-01-01

    Geochemical effects of electro-osmosis in bentonite clay are studied in the laboratory, where a 6 mm thick bentonite layer\\u000a is subjected to direct current. Acidification and alkalization near anode and cathode are expected, possibly causing mineral\\u000a deterioration, ion mobilization and precipitation of new solids. Afterwards the clay is analysed by XRF and anolyte and catholyte\\u000a are analysed by ICP-MS. In addition,

  8. Field trip guidebook on environmental impact of clays along the upper Texas coast

    NASA Technical Reports Server (NTRS)

    Garcia, Theron D.; Ming, Douglas W.; Tuck, Lisa Kay

    1991-01-01

    The field trip was prepared to provide an opportunity to see first hand some the environmental hazards associated with clays in the Houston, Texas area. Because of the very high clay content in area soils and underlying Beaumont Formation clay, Houston is a fitting location to host the Clay Mineral Society. Examinations were made of (1) expansive soils, (2) subsidence and surface faulting, and (3) a landfill located southeast of Houston at the Gulf Coast Waste Disposal Authority where clay is part of the liner material.

  9. NONINVASIVE COMPLEX RESISTIVITY MEASUREMENTS OF CLAY ORGANIC PROCESSES TO MAP ORGANIC CONTAMINATION AND DEGRADATION OF CLAY BARRIERS F49620-95-1-0350

    Microsoft Academic Search

    Gary R. Olhoeft

    One of the most difficult problems in environmental remediation is location of subsurface organic contaminants (3). Most common organic contaminants are known to react with clay minerals (1, 3). However, while many clay-organic reaction processes are known, only a few have been the subject of detailed studies (1, 4). More problematical, some of these reactions alter the physical properties of

  10. Structure and clay mineralogy: borehole images, log interpretation and sample analyses at Site C0002 Nankai Trough accretionary prism

    NASA Astrophysics Data System (ADS)

    Jurado, Maria Jose; Schleicher, Anja

    2015-04-01

    Our research focused on the characterization of fracture and fault structures from the deep Nankai Trough accretionary prism in Japan. Logging Data and cuttings samples from the two most recent International Ocean Discovery Program (IODP) Expeditions 338 and 348 of the NanTroSEIZE project were analyzed by Logging While Drilling (LWD) oriented images, geophysical logs and clay mineralogy. Both expeditions took place at Site C0002, but whereas Hole C0002F (Expedition 338) was drilled down to 2004.5 mbsf, Hole C0002N and C0002P (Expedition 348) reached a depth of 2325.5 mbsf and 3058.8 mbsf respectively. The structural interpretation of borehole imaging data illustrates the deformation within the fractured and faulted sections of the accretionary prism. All drill holes show distinct areas of intense fracturing and faulting within a very clay-dominated lithology. Here, smectite and illite are the most common clay minerals, but the properties and the role they may play in influencing the fractures, faults and folds in the accretionary prism is still not well understood. When comparing clay mineralogy and fracture/fault areas in hole C0002F (Expedition 338), a trend in the abundance of illite and smectite, and in particular the swelling behavior of smectite is recognizable. In general, the log data provided a good correlation with the actual mineralogy and the relative abundance of clay. Ongoing postcruise preliminary research on hole C0002 N and C0002P (Expedition 348) should confirm these results. The relationship between fracture and fault structures and the changes in clay mineralogy could be explained by the deformation of specific areas with different compaction features, fluid-rock interaction processes, but could also be related to beginning diagenetic processes related to depth. Our results show the integration of logging data and cutting sample analyses as a valuable tool for characterization of petrophysical and mineralogical changes of the structures of the Nankai accretionary prism. This is critical for our understanding of clay-fluid interaction and mechanical properties duing fault displacements and seismogenesis.

  11. Biodegradation of crude oil saturated fraction supported on clays.

    PubMed

    Ugochukwu, Uzochukwu C; Jones, Martin D; Head, Ian M; Manning, David A C; Fialips, Claire I

    2014-02-01

    The role of clay minerals in crude oil saturated hydrocarbon removal during biodegradation was investigated in aqueous clay/saturated hydrocarbon microcosm experiments with a hydrocarbon degrading microorganism community. The clay minerals used for this study were montmorillonite, palygorskite, saponite and kaolinite. The clay mineral samples were treated with hydrochloric acid and didecyldimethylammonium bromide to produce acid activated- and organoclays respectively which were used in this study. The production of organoclay was restricted to only montmorillonite and saponite because of their relative high CEC. The study indicated that acid activated clays, organoclays and unmodified kaolinite, were inhibitory to biodegradation of the hydrocarbon saturates. Unmodified saponite was neutral to biodegradation of the hydrocarbon saturates. However, unmodified palygorskite and montmorillonite were stimulatory to biodegradation of the hydrocarbon saturated fraction and appears to do so as a result of the clays' ability to provide high surface area for the accumulation of microbes and nutrients such that the nutrients were within the 'vicinity' of the microbes. Adsorption of the saturated hydrocarbons was not significant during biodegradation. PMID:23670057

  12. Inter-layered clay stacks in Jurassic shales

    NASA Technical Reports Server (NTRS)

    Pye, K.; Krinsley, D. H.

    1983-01-01

    Scanning electron microscopy in the backscattered electron mode is used together with energy-dispersive X-ray microanalysis to show that Lower Jurassic shales from the North Sea Basin contain large numbers of clay mineral stacks up to 150 microns in size. Polished shale sections are examined to determine the size, shape orientation, textural relationships, and internal compositional variations of the clays. Preliminary evidence that the clay stacks are authigenic, and may have formed at shallow burial depths during early diagenesis, is presented.

  13. Adsorption and Desorption of Nitrogen and Water Vapor by clay

    NASA Astrophysics Data System (ADS)

    Cui, Deshan; Chen, Qiong; Xiang, Wei; Huang, Wei

    2015-04-01

    Adsorption and desorption of nitrogen and water vapor by clay has a significant impact on unsaturated soil physical and mechanical properties. In order to study the adsorption and desorption characteristics of nitrogen and water vapor by montmorillonite, kaolin and sliding zone soils, the Autosorb-iQ specific surface area and pore size analyzer instrument of United State was taken to carry out the analysis test. The adsorption and desorption of nitrogen at 77K and water vapor at 293K on clay sample were conducted. The theories of BET, FHH and hydration energy were taken to calculate the specific surface, surface fractal dimension and adsorption energy. The results show that the calculated specific surface of water vapor by clay is bigger than nitrogen adsorption test because clay can adsorb more water vapor molecule than nitrogen. Smaller and polar water vapor molecule can access the micropore and then adsorb on the mineral surface and mineral intralayer, which make the mineral surface cations hydrate and the mineral surface smoother. Bigger and nonpolar nitrogen molecule can not enter into the micropore as water vapor molecule and has weak interaction with clay surface.

  14. Columns in Clay

    ERIC Educational Resources Information Center

    Leenhouts, Robin

    2010-01-01

    This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

  15. External Resource: Clay Planets

    NSDL National Science Digital Library

    1900-01-01

    In this activity, learners/students use given amounts of clay to create models of the solar system. Learners/students use clay to represent different planets and other objects in the solar system (asteroids, moons, etc.). The learners/students can use as

  16. Sb(III) and Sb(V) Sorption onto Al-Rich Phases: Hydrous Al Oxide and the Clay Minerals Kaolinite KGa-1b and Oxidized and Reduced Nontronite NAu-1

    SciTech Connect

    Ilgen, Anastasia G.; Trainor, Thomas P. (Alaska Fairbanks)

    2012-11-13

    We have studied the immobilization of Sb(III) and Sb(V) by Al-rich phases - hydrous Al oxide (HAO), kaolinite (KGa-1b), and oxidized and reduced nontronite (NAu-1) - using batch experiments to determine the uptake capacity and the kinetics of adsorption and Extended X-ray Absorption Fine Structure (EXAFS) Spectroscopy to characterize the molecular environment of adsorbed Sb. Both Sb(III) and Sb(V) are adsorbed in an inner-sphere mode on the surfaces of the studied substrates. The observed adsorption geometry is mostly bidentate corner-sharing, with some monodentate complexes. The kinetics of adsorption is relatively slow (on the order of days), and equilibrium adsorption isotherms are best fit using the Freundlich model. The oxidation state of the structural Fe within nontronite affects the adsorption capacity: if the clay is reduced, the adsorption capacity of Sb(III) is slightly decreased, while Sb(V) uptake is increased significantly. This may be a result of the presence of dissolved Fe(II) in the reduced nontronite suspensions or associated with the structural rearrangements in nontronite due to reduction. These research findings indicate that Sb can be effectively immobilized by Al-rich phases. The increase in Sb(V) uptake in response to reducing structural Fe in clay can be important in natural settings since Fe-rich clays commonly go through oxidation-reduction cycles in response to changing redox conditions.

  17. Polymer-clay nanocomposites as precursors of nanostructured carbon materials for electrochemical devices: templating effect of clays.

    PubMed

    Fernández-Saavedra, Rocío; Darder, Margarita; Gómez-Avilés, Almudena; Aranda, Pilar; Ruiz-Hitzky, Eduardo

    2008-04-01

    The present work introduces a comparative study on the use of polymer nanocomposites containing clay minerals of different structure, such as montmorillonite and sepiolite as host solids for the templating synthesis of carbon-like materials from different organic precursors. Carbon-clay nanocomposites were obtained by polymerization of either acrylonitrile or sucrose previously inserted in the pores of the clay minerals, followed by their further thermal transformation in carbon-like compounds. Acid treatment of the resulting carbon-clay nanocomposites removes the inorganic templates giving carbon-like materials with different textural features. Polymer-clay, carbon-clay and carbon-like materials have been characterized by applying spectroscopic techniques as FTIR and in situ EIS (electrochemical impedance spectroscopy) and other structural, textural and analytical tools (chemical analysis, XRD, SEM-EDX, TEM-EDX, N2 adsorption isotherms,...). Electrochemical properties of these carbon-clay nanocomposites, as well as their templated carbonaceous materials and their use as electrode materials of different electrochemical devices such as rechargeable Li-batteries, supercapacitors and electrochemical sensors, are also discussed. PMID:18572573

  18. Chemistry, mineralogy and origin of the clay-hill nitrate deposits, Amargosa River valley, Death Valley region, California, U.S.A.

    USGS Publications Warehouse

    Ericksen, G.E.; Hosterman, J.W.; St., Amand, P.

    1988-01-01

    The clay-hill nitrate deposits of the Amargosa River valley, California, are caliche-type accumulations of water-soluble saline minerals in clay-rich soils on saline lake beds of Miocene, Pliocene(?) and Pleistocene age. The soils have a maximum thickness of ??? 50 cm, and commonly consist of three layers: (1) an upper 5-10 cm of saline-free soil; (2) an underlying 15-20 cm of rubbly saline soil; and (3) a hard nitrate-rich caliche, 10-20 cm thick, at the bottom of the soil profile. The saline constituents, which make up as much as 50% of the caliche, are chiefly Cl-, NO-3, SO2-4 and Na+. In addition are minor amounts of K+, Mg2+ and Ca2+, varying, though generally minor, amounts of B2O3 and CO2-3, and trace amounts of I (probably as IO-3), NO-2, CrO2-4 and Mo (probably as MoO2-4). The water-soluble saline materials have an I/Br ratio of ??? 1, which is much higher than nearly all other saline depostis. The principal saline minerals of the caliche are halite (NaCl), nitratite (NaNO3), darapskite (Na3(SO4)(NO3)??H2O), glauberite (Na2Ca(SO4)2), gypsum (CaSO4??2H2O) and anhydrite (CaSO4). Borax (Na2B4O5(OH)4??8H2O), tincalconite (Na2B4O5(OH)4??3H2O) and trona (Na3(CO3)(HCO3)??2H2O) are abundant locally. The clay-hill nitrate deposits are analogous to the well-known Chilean nitrate deposits, and probably are of similar origin. Whereas the Chilean deposits are in permeable soils of the nearly rainless Atacama Desert, the clay-hill deposits are in relatively impervious clay-rich soils that inhibited leaching by rain water. The annual rainfall in the Death Valley region of ??? 5 cm is sufficient to leach water-soluble minerals from the more permeable soils. The clay-hill deposits contain saline materials from the lake beds beneath the nitrate deposits are well as wind-transported materials from nearby clay-hill soils, playas and salt marshes. The nitrate is probably of organic origin, consisting of atmospheric nitrogen fixed as protein by photoautotrophic blue-green algae, which are thought to form crusts on soils at the sites of the deposits when moistened by rainfall. The protein is subsequently transformed to nitrate by autotophic bacteria. ?? 1988.

  19. Zeta Potential Measurements on Three Clays from Turkey and Effects of Clays on Coal Flotation

    PubMed

    Hussain; Dem&idot;rc&idot;; özbayoğlu

    1996-12-25

    There is a growing trend of characterizing coal and coal wastes in order to study the effect of clays present in them during coal washing. Coarse wastes from the Zonguldak Coal Washery, Turkey, were characterized and found to contain kaolinite, illite, and chlorite. These three clays, obtained in almost pure form from various locations in Turkey, have been subjected to X-ray diffraction (XRD) analysis to assess their purity and zeta potential measurements in order to evaluate their properties in terms of their surface charge and point of zero charge (pzc) values. It was found from XRD data that these clays were almost pure and their electrokinetic potential should therefore be representative of their colloidal behavior. All three clay minerals were negatively charged over the range from pH 2.5 to 11. Chlorite and illite have pzc at pH 3 and pH 2.5, respectively, whereas kaolinite has no pzc. The effect of these clays in Zonguldak coal, wastes, and black waters on coal flotation was studied by floating artificial mixtures of Zonguldak clean coal (4.5% ash) and individual clay. The flotation tests on coal/individual clay revealed that each clay influences coal flotation differently according to its type and amount. Illite had the worst effect on coal floated, followed by chlorite and kaolinite. The loss of yield in coal was found to be 18% for kaolinite, 20% for chlorite, and 28% for illite, indicating the worst effect of illite and least for kaolinite during coal flotation. PMID:8978557

  20. Analysis of Layer Charge, Cation and Anion Exchange Capacities, and Synthesis of Reduced Charge Clays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface charge is one of the most important properties of clay minerals. Surface charge is used in classification of 2:1 phyllosilicates and has a strong influence on properties of clays such as hydration, swelling, cation exchange, and reactions with organic molecules. In this chapter, analytical m...

  1. Temperature and pH controls over isotopic fractionation during adsorption of boron on marine clay

    Microsoft Academic Search

    M. R. Palmer; A. J. Spivack; J. M. Edmond

    1987-01-01

    The variation of adsorption constants and isotope fractionation with pH and temperature during the adsorption of B from sea water onto marine clay have been examined. The controls over adsorption are similar to those exhibited by pure clay minerals. The isotope fractionations are the result of equilibrium processes, not kinetic effects. Variations in the measured fractionation factor with pH arise

  2. Mössbauer, X-ray and derivatographic studies on Egyptian Nile clay

    NASA Astrophysics Data System (ADS)

    Eissa, N. A.; Gomaa, S. Sh.; Hassaan, M. Y.; Sallam, H. A.

    1988-12-01

    The constituents of the clay minerals in eighteen Nile clay and two Desert (calcareous) samples, were investigated. The physicochemical transformations induced in the iron containing phases were followed by heat treatment. A conclusion was reached about the behaviour of the ferrous and ferric ions at various temperatures. This behabviour is applied to characterize the archaeological Ancient Egyptian pottery.

  3. Chemical and mineralogical characteristics of French green clays used for healing

    USGS Publications Warehouse

    Williams, L.B.; Haydel, S.E.; Giese, R.F.; Eberl, D.D.

    2008-01-01

    The worldwide emergence of infectious diseases, together with the increasing incidence of antibiotic-resistant bacteria, elevate the need to properly detect, prevent, and effectively treat these infections. The overuse and misuse of common antibiotics in recent decades stimulates the need to identify new inhibitory agents. Therefore, natural products like clays, that display antibacterial properties, are of particular interest. The absorptive properties of clay minerals are well documented for healing skin and gastrointestinal ailments. However, the antibacterial properties of clays have received less scientific attention. French green clays have recently been shown to heal Buruli ulcer, a necrotic or 'flesh-eating' infection caused by Mycobacterium ulcerans. Assessing the antibacterial properties of these clays could provide an inexpensive treatment for Buruli ulcer and other skin infections. Antimicrobial testing of the two clays on a broad-spectrum of bacterial pathogens showed that one clay promotes bacterial growth (possibly provoking a response from the natural immune system), while another kills bacteria or significantly inhibits bacterial growth. This paper compares the mineralogy and chemical composition of the two French green clays used in the treatment of Buruli ulcer. Mineralogically, the two clays are dominated by 1Md illite and Fe-smectite. Comparing the chemistry of the clay minerals and exchangeable ions, we conclude that the chemistry of the clay, and the surface properties that affect pH and oxidation state, control the chemistry of the water used to moisten the clay poultices and contribute the critical antibacterial agent(s) that ultimately debilitate the bacteria. Copyright ?? 2008, The Clay Minerals Society.

  4. Clay Mineralogy in Building Research

    Microsoft Academic Search

    J. E. Gillott

    1962-01-01

    Clay is important in the construction industry both as a building material and as a foundation for structures. Buildings and utensils made of clay date back to the earliest periods of man's civilized development, and the use of clay is intimately associated with his history. Sun-baked clay structures were built during the pre-European period of American history. In the southwest

  5. Occurrences of alunite, prophyllite, and clays in the Cerro La Tiza area, Puerto Rico

    USGS Publications Warehouse

    Hildebrand, Fred Adelbert; Smith, Raymond J.

    1959-01-01

    A deposit of hydrothermally altered rocks in the Cerro La Tiza area located between the towns of Comerio and Aguas Buenas, approximately 25 kilometers southwest of San Juan, Puerto Rico, was mapped and studied to determine the principal minerals, their extent distribution and origin, and the possibility of their economic utilization, especially in Puerto Rico. The Cerro la Tiza area is about 7? kilometers long, has an average width of about 1? kilometers and embraces a total area of approximately 15 square kilometers. The principal mineralized zone, a dike-like mass of light-colored rocks surrounded by dark-colored volcanic country rocks, occupies the crest and upper slopes of east-trending Cerro La Tiza ridge and is believed to be of Late Cretaceous or Eocene age. This zone is approximately 5,300 meters long, 430 meters wide and has an area of approximately 225 hectares (556 acres). The rocks of the mineralized zone are of mixed character and consist mainly of massive quartzose rocks and banded quartz-alunite rocks closely associated with foliated pyrophyllitic, sericitic and clayey rocks. The principal minerals in probably order of abundance are quartz, alunite, pyrophyllite, kaolin group clays (kaolinite and halloysite) and sericite. Minerals of minor abundance are native sulfure, diaspore, svanbergite (?), sunyite (?), hematite, goethite, pyrite, rutile (?) and very small quantities of unidentified minerals. The mineralized zone has broken down to deposits of earth-rock debris of Quaternary age that cover much of the slopes and flanks of Cerro La Tiza. This debris consists generally of fragments and boulders with a very large size range embedded in a clayey matrix. The distribution of the earth-rock debris with respect to the present topography and drainage suggests that it may have undergone at least two cycles of erosion. Underlying the earth-rock debris and completely enclosing the mineralized zone are country rocks of probably Late Cretaceous age. These consist principally of low flows and volcanic and flow breccias but contain thin interbedded siltstones and sandstones. The lavas are generally predominant at the western end of the area and the breccias at the eastern end. The mineralized zone and the country rocks are sheared along two predominant directions that are approximately N 70 degrees E and N 70 degrees W. The ridge of Cerro La Tiza appears to be a broad shear zone through which hydrothermal emanations gained access to the country rocks. The emanations are believed to have originated from intrusive rocks that probably underlie the area. The surrounding area contains both large and small exposed intrusive bodies. The largest one is the San Lorenzo batholith of Late Cretaceous or Eocene age whose exposed northwest edge is approximately 19 kilometers southeast of the eastern end of the Cerro La Tiza area. Other zones of hydrothermally altered rocks were discovered along a mineralized belt extending eastward from Cerro La Tiza through the Rio Gurabo Valley nearly to the Vieques Passage bordering the east coast of Puerto Rico. Other zones were discovered north and south of this belt and still others were found circumventing the San Lorenzo batholith. The most abundant minerals of the mineralized zone can be exploited for economic utilization in Puerto Rico. Alunite can be utilized in the manufacture of aluminum sulfate for water purification. It can also be used in the manufacture of alumina refractory materials. Pyrophyllite can be used as a carrier for insecticides and fungicides. It can also be utilized for the manufacture of ceramic products, as a filler in the soap industry and as a carrier for paint pigments. Kaolinite can be used in the ceramic industry and in the manufacture of glass as a substitute for feldspar. Halloysite might be utilized as a catalyst support in the cracking of petroleum. Tonnages of reserve ore on Cerro La Tiza are calculated to be 1,590,000 inferred short tons (1,4

  6. Sample preparation of x-ray diffraction analysis and clay mineralogy of Devonian shale from the Appalachian basin

    SciTech Connect

    Hosterman, J.W.; Loferski, P.J.

    1981-03-01

    Three well-known methods of preparing the clay fraction for x-ray diffraction analysis were tested and evaluated. Kaolinite was not identified in samples prepared by the two settling methods because of layering due to differing/settling rates of the clay minerals. It is suggested that if one of the two settling methods of sample preparation is used that the clay film should be thin enough for the x-ray beam to penetrate the entire thickness of clay. The vacuum method of sample preparation is preferred. Chlorite, kaolinite, 2M illite (muscovite), and mixed layer are the clay minerals found by x-ray diffraction analysis in Devonian shale of the Appalachian basin. The proportions of mixed-layer clay minerals were determined by comparing areas of selected basal peaks on x-ray diffraction traces of untreated samples with those of samples that had been heated and saturated by ethylene glycol.

  7. Characterisation of kaolinitic clays from the Ivory Coast (West Africa)

    Microsoft Academic Search

    J. Sei; A. Abba Touré; J. Olivier-Fourcade; H. Quiquampoix; S. Staunton; J. C. Jumas; M. Womes

    2004-01-01

    Clays from different deposits in the Ivory Coast (Adattié (ADA), Nieki (NIE), Grand-Bassam (BAS), Nigui-Saff (NS)) were studied using various techniques. Their chemical compositions were determined by X-ray fluorescence and the most important crystalline phases were identified by X-ray diffraction. Kaolinite is the dominant mineral phase with minor amounts of other minerals including quartz, haematite, goethite, lepidocrocite and illite. The

  8. Heterogeneous uptake of nitric acid on Na-montmorillonite clay as a function of relative humidity

    Microsoft Academic Search

    C. D. Mashburn; E. K. Frinak; M. A. Tolbert

    2006-01-01

    Atmospheric mineral aerosol is a potentially important reactive surface that may provide a heterogeneous sink for gas phase species such as nitric acid (HNO3). We have studied the uptake of HNO3 on Na-montmorillonite, a swelling clay mineral, at low temperatures as a function of relative humidity (RH), HNO3 pressure and clay mass. Condensed phase products were probed with transmission Fourier

  9. Common clay and shale

    USGS Publications Warehouse

    Virta, R.L.

    2006-01-01

    At present, 150 companies produce common clay and shale in 41 US states. According to the United States Geological Survey (USGS), domestic production in 2005 reached 24.8 Mt valued at $176 million. In decreasing order by tonnage, the leading producer states include North Carolina, Texas, Alabama, Georgia and Ohio. For the whole year, residential and commercial building construction remained the major market for common clay and shale products such as brick, drain tile, lightweight aggregate, quarry tile and structural tile.

  10. The composition and origin of Ghana medicine clays

    PubMed Central

    van Dongen, Bart E.; Fraser, Sharon E.; Insoll, Timothy

    2011-01-01

    The mineral, organic and elemental composition of medicine clays from three shrines in the Tong Hills in northern Ghana (Gbankil, Kusanaab, and Yaane) are assessed to ascertain what additives they might contain and the implications for their recognition, for example in archaeological contexts. These are clays that are widely used for healing purposes being perceived efficacious in curing multiple ailments and which are given a divine provenance, but their collection is ascribed human agency. The Yaane clay is also supplied as part of the process of obtaining the right to operate the shrine elsewhere making it widely dispersed. Organic geochemical analyses revealed a predominance of plant-derived material with a substantial contribution of microbial origin. Based on these (supported by elemental and mineral analyses), no unnatural organic material could be detected, making an exogenous contribution to these clays unlikely. The implications are that these are wholly natural medicinal substances with no anthropogenic input into their preparation, as the traditions suggest. The very similar mineralogy of all the clays, including a non-medicine clay sampled, suggests that, unless the geology radically differed, differentiating between them analytically in an archaeological contexts would be doubtful. PMID:21810043

  11. Liquid-crystalline aqueous clay suspensions.

    PubMed

    Michot, Laurent J; Bihannic, Isabelle; Maddi, Solange; Funari, Sérgio S; Baravian, Christophe; Levitz, Pierre; Davidson, Patrick

    2006-10-31

    This article demonstrates the occurrence of a true isotropic/nematic transition in colloidal Brownian aqueous suspensions of natural nontronite clay. The liquid-crystalline character is further evidenced by polarized light microscopy and small-angle x-ray scattering experiments in the presence and absence of modest external magnetic fields. The complete phase diagram ionic strength/volume fraction then exhibits a clear biphasic domain in the sol region just before the gel transition in contrast with the situation observed for other swelling clays in which the sol/gel transition hinders the isotropic/nematic transition. Small-angle x-ray scattering measurements of gel samples reveal strong positional and orientational orders of the particles, proving unambiguously the nematic character of the gel and, thus, clearly refuting the still prevalent "house of cards" model, which explains the gel structure by means of attractive interactions between clay platelets. Such order also is observed in various other swelling clay minerals; therefore, this very general behavior must be taken into account to reach a better understanding of the rheological properties and phase behavior of these systems. PMID:17060625

  12. Clay-based polymer nanocomposites: research and commercial development.

    PubMed

    Zeng, Q H; Yu, A B; Lu, G Q; Paul, D R

    2005-10-01

    This paper reviews the recent research and development of clay-based polymer nanocomposites. Clay minerals, due to their unique layered structure, rich intercalation chemistry and availability at low cost, are promising nanoparticle reinforcements for polymers to manufacture low-cost, lightweight and high performance nanocomposites. We introduce briefly the structure, properties and surface modification of clay minerals, followed by the processing and characterization techniques of polymer nanocomposites. The enhanced and novel properties of such nanocomposites are then discussed, including mechanical, thermal, barrier, electrical conductivity, biodegradability among others. In addition, their available commercial and potential applications in automotive, packaging, coating and pigment, electrical materials, and in particular biomedical fields are highlighted. Finally, the challenges for the future are discussed in terms of processing, characterization and the mechanisms governing the behaviour of these advanced materials. PMID:16245517

  13. Controlling Harmful Algal Blooms Through Clay Flocculation1

    Microsoft Academic Search

    MARIO R. SENGCO; DONALD M. ANDERSON

    2004-01-01

    ABSTRACT. The potential use of clays to control harmful algal blooms (HABs) has been explored in East Asia, Australia, the United States, and Sweden. In Japan and South Korea, minerals such as montmorillonite, kaolinite, and yellow loess, have already been used in the field effectively, to protect fish mariculture fromCochlodiniumspp. and other blooms. Cell removal occurs through the flocculation of

  14. Water film thickness in the clay-water system

    Microsoft Academic Search

    Hiroshi Makihara

    1999-01-01

    The permeable press experiment was performed for aqueous clay mineral systems to understand the relationship between the water film thickness and the applied permeable pressure. Water film thickness between particles was calculated from the particle size and the linear drying shrinkage of pressed bodies. The permeable press experimental results were compared to the calculated total interaction pressures between particles using

  15. Clay Formation Dominantly in the Subsurface? Implications for Early Mars Environments

    NASA Astrophysics Data System (ADS)

    Ehlmann, B. L.; Mustard, J. F.; Murchie, S. L.; Bibring, J.; Meunier, A.; Fraeman, A. A.; Langevin, Y.

    2011-12-01

    Alteration minerals preserved in the ancient crust of Mars record changes in water availability, climate, and potential habitats for life during the first billion years of the planet's history. Widespread clay minerals discovered in Noachian (>~3.7 Gyr) terrains indicate long-duration alteration by neutral to high pH water; however, to date, evidence for specific environmental conditions, e.g. weathering, lacustrine, or hydrothermal clay formation, has been ambiguous. We examined mineral associations in clay-bearing terrains, considered relative ages and stratigraphic relationships of alteration mineral-bearing deposits, and evaluated models for aqueous alteration of basalt. Available data are consistent with clay mineral formation by mostly subsurface aqueous processes during the Noachian epoch. Low water:rock ratio processes in largely closed-system conditions formed Fe/Mg phyllosilicates (smectites, chlorites) from basaltic materials at temperatures ranging from ambient to 300 C. The Fe/Mg clay-bearing units formed are volumetrically large and occupy some of the deepest exposed stratigraphic units; however, their formation would have resulted in little change in the bulk chemistry of Noachian crustal rocks. In contrast to the Noachian crustal clay deposits dominated by Fe/Mg phyllosilicates with other diverse hydrated silicate phases, stratigraphically higher deposits contain clay minerals with more Al clays (kaolinite, montmorillonite), silica, and salts. These appear to have formed later under open-system, surface to near-surface alteration. These findings suggest that continuously warm surface conditions with stable liquid water did not need to be maintained in order to form clays during the Noachian. Instead, surface waters may have been geologically brief and the longest-lived aqueous environments on early Mars may have been in the subsurface.

  16. Deuterium abundances

    E-print Network

    M. Lemoine; J. Audouze; L. Ben Jaffel; P. Feldman; R. Ferlet; G. Hebrard; E. B. Jenkins; C. Mallouris; W. Moos; K. Sembach; G. Sonneborn; A. Vidal-Madjar; D. G. York

    1999-03-02

    We discuss the measurements of deuterium abundances in high redshift quasar absorbers, in the solar system and in the interstellar medium. We present new results that indicate spatial variations of the deuterium abundance in the interstellar medium at the level of 50% over scales possibly as small as 10 pc, and discuss plausible causes for the origin of these variations.

  17. Clay-based geothermal drilling fluids

    SciTech Connect

    Guven, N.; Carney, L.L.; Lee, L.J.; Bernhard, R.P.

    1982-11-01

    The rheological properties of fluids based on fibrous clays such as sepiolite and attapulgite have been systematically examined under conditions similar to those of geothermal wells, i.e. at elevated temperatures and pressures in environments with concentrated brines. Attapulgite- and sepiolite-based fluids have been autoclaved at temperatures in the range from 70 to 800/sup 0/F with the addition of chlorides and hydroxides of Na, K, Ca, and Mg. The rheological properties (apparent and plastic viscosity, fluid loss, gel strength, yield point, and cake thickness) of the autoclaved fluids have been studied and correlated with the chemical and physical changes that occur in the clay minerals during the autoclaving process.

  18. Microbial Decomposition of Extracellular DNA in Clay Soils

    NASA Astrophysics Data System (ADS)

    Morrissey, E. M.; McHugh, T. A.; Schwartz, E.; Preteska, L.; Hayer, M.; Hungate, B. A.

    2014-12-01

    Genomic analysis of soil communities can only be useful in predicting ecosystem processes if the genetic data gathered is representative of the microbial community. Consequently, extracellular DNA (eDNA) represents a pool of unexpressed genetic information that may skew genomic analyses. To date, our understanding of the representation of eDNA in metagenomic data and its decomposition in soil is very limited. To address this deficit, we performed a laboratory experiment wherein soils were amended with eDNA and/or clay minerals in a full factorial design. Specifically, the decomposition of 13C labeled E. coli DNA was monitored over a 30-day period in control, Kaolinite-amended, and Montmorillonite-amended soils. The amount of added eDNA carbon (C) remaining in the soil declined exponentially over time, with the majority of decomposition occurring in the first two weeks. Kaolinite significantly decreased eDNA decomposition rates and retained a higher fraction of eDNA-C (~70% remaining) than unamended and Montmorillonite-soils (~40% remaining) after 30 days. Phylogenetic (16S rRNA) sequencing of DNA extracted over the course of the incubation period enabled detection of the added eDNA. The relative abundance of added E. coli DNA decreased ~10-100 fold over 30 days. These results indicate that while a significant fraction of eDNA-C remained in the soil, this carbon was likely no longer in the form of intact strands of DNA amenable to sequencing. In addition, the eDNA affected the composition of the bacterial community. Specifically, the relative abundance of Planctomycetes and TM7 were elevated in soils that received eDNA regardless of clay addition, suggesting these phyla may be particularly effective at degrading eDNA and using it for growth. In conclusion these results indicate that the representation of eDNA in metagenomic sequence data declines rapidly, likely due to fragmentation. However, a fraction of eDNA material was resistant to decomposition, suggesting a substantial amount of recalcitrant eDNA could accumulate over time.

  19. Oxygen and hydrogen isotopic composition of clay minerals of the Bahloul Formation in the region of the Bou Grine zinc–lead ore deposit (Tunisia): evidence for fluid–rock interaction in the vicinity of salt dome cap rock

    Microsoft Academic Search

    A. Bechtel; S. M. Savin; S. Hoernes

    1999-01-01

    The siliciclastic Bahloul Formation of Tunisia is the host for Zn\\/Pb deposits. A detailed study of 18O\\/16O and D\\/H ratios of kaolinite, quartz and calcite was done to elucidate the conditions and mechanism of deposition of the diapir-related Bou Grine Zn\\/Pb ores in the formation. D\\/H and 18O\\/16O ratios of the minerals of the host rock have been affected by

  20. 30. TRACE ELEMENT AND SR-ISOTOPIC CONTENTS OF HYDROTHERMAL CLAYS AND SULFIDES FROM THE SNAKE PIT HYDROTHERMAL FIELD: ODP SITE 649 1

    Microsoft Academic Search

    Kathryn M. Gillis; Alan D. Smith; John N. Ludden

    Several meters of unconsolidated hydrothermal sediment were recovered from the Snake Pit hydrothermal field during ODP Leg 106. Polymetallic sulfides comprise most of the sediment with minor fragments of massive sulfide, organic debris, clay minerals, and fresh glass shards. Trace element and Sr-isotope contents of hydrothermal clays and sulfides from Holes 649B and 649G indicate that these minerals precipitated from

  1. The role of remote sensing in finding hydrothermal mineral deposits on earth.

    PubMed

    Huntington, J F

    1996-01-01

    The identification of surface mineralogical composition using hyperspectral sensors is now the major remote sensing opportunity for exploration geologists seeking refined vectors to potential ore-bearing hydrothermal systems. This involves no less than remote, visible and infrared spectroscopy of the molecular composition of geological materials from remote platforms using a large number of calibrated spectral bands. From field-portable systems to those flying in high-flying aircraft on the edges of space, it is now possible to define a long list of minerals and their weathering products detectable at these wavelengths. These include hydroxyl-bearing minerals such as hydrothermal clays, sulfates, ammonium-bearing minerals, phyllosilicates, iron oxides, carbonates, and a wide range of silicates. Indeed, even the chemical composition of micas and chlorites has been mapped remotely using subtle wavelength shifts in their diagnostic reflectance spectra, indicating varying degrees of Na, K, Al, Mg and Fe substitution. Spatial zones, relative abundances and assemblages of these minerals allow geologists to reconstruct the mineralogical, chemical and sometimes thermal disposition of ancient hydrothermal systems in their search for optimal drilling targets. Such minerals not only result directly from the hydrothermal processes involved but may also 'expose' older host rocks caught up in the process and brought to the surface. New microwave radar systems are also shedding new light on landscape processes, textures and structure and occasionally penetrating dry surface layers to reveal buried structures. PMID:9243018

  2. Silt-clay aggregates on Mars

    NASA Technical Reports Server (NTRS)

    Greeley, R.

    1979-01-01

    Viking observations suggest abundant silt and clay particles on Mars. It is proposed that some of these particles agglomerate to form sand size aggregates that are redeposited as sandlike features such as drifts and dunes. Although the binding for the aggregates could include salt cementation or other mechanisms, electrostatic bonding is considered to be a primary force holding the aggregates together. Various laboratory experiments conducted since the 19th century, and as reported here for simulated Martian conditions, show that both the magnitude and sign of electrical charges on windblown particles are functions of particle velocity, shape and composition, atmospheric pressure, atmospheric composition and other factors. Electrical charges have been measured for saltating particles in the wind tunnel and in the field, on the surfaces of sand dunes, and within dust clouds on earth. Similar, and perhaps even greater, charges are proposed to occur on Mars, which could form aggregates of silt and clay size particles

  3. Wellbore instability mechanisms in clays

    E-print Network

    Akl, Sherif Adel

    2011-01-01

    This dissertation investigates the stability of wellbores drilled in Ko-consolidated clays using non-linear finite element method (FEM) and effective stress soil models to characterize the behavior of clay and unconsolidated ...

  4. Mineral Surface Reactivity in teaching of Science Materials

    NASA Astrophysics Data System (ADS)

    Del Hoyo Martínez, Carmen

    2013-04-01

    In the last fifty years, science materials issues has required the study of air pollution, water and soil to prevent and remedy the adverse effects of waste originating from anthropogenic activity and the development of new energies and new materials. The teaching of this discipline has been marked by lectures on general lines, materials, disciplines, who explained biased objects of reality, but often forgot the task of reconstruction and integration of such visions. Moving from that model, otherwise quite static, to a dynamic relational model, would in our view, a real revolution in education. This means taking a systematic approach to complex both in interpreting reality and in favor when learning. Children relationships are as important or more than single objects, and it is to discover fundamental organizational principles of phenomena we seek to interpret or in other words, find the pattern that connects. Thus, we must work on relationships and also take into account the relation between the observer and the observed. Educate about relationships means that studies should always be considered within a framework of probabilities, not absolute certainties. This model of systemic thinking, dealing with complexity, is a possibility to bring coherence to our educational work, because the complexity is not taught, complexity is live, so that complex thinking is extended (and fed) in a form educate complex. It is the task of teaching to help people move from level to level of decision reviews. This means that systems thinking should be extended in a local action, action that engages the individual and the environment. Science Materials has emerged as a discipline of free choice for pupils attending chemical engineering which has been assigned 6.0 credits. The chemical engineer's professional profile within the current framework is defined as a professional knowledge as a specialization technical / functional, working in a learning organization and the formation of which enables him to continuous innovation. Different materials are used in the adsorption and improvement and design of new adsorbents, most of whom remain under patent, so they do not know the procedures and products used, but in all cases the safety and / or biodegradability of materials used is an important issue in their choice for environmental applications. In regard to materials, safe and low cost must be mentioned clays and clay minerals, whose colloidal properties, ease of generating structural changes, abundance in nature, and low cost make them very suitable for adsorption chemical contaminants. We proposed to use these materials to show the different aspects for the study of the Science Materials. References -del Hoyo, C. (2007b). Layered Double Hydroxides and human health: An overview. Applied Clay Science. 36, 103-121. -Konta, J. (1995). Clay and man: Clay raw materials in the service of man. Applied Clay Science. 10, 275-335. -Volzone, C. (2007). Retention of pollutant gases: Comparison between clay minerals and their modified products. Applied Clay Science. 36, 191-196.

  5. Kimonos in Clay.

    ERIC Educational Resources Information Center

    Stern, Debbie

    1999-01-01

    Describes an art activity for third-grade students where they create their own Japanese clay dolls complete with kimonos and obies after learning about Japanese culture and the importance of kimonos. Discusses the process of making the dolls and kimonos in detail. (CMK)

  6. Organic Pillared Clays

    Microsoft Academic Search

    L. P. Meier; R. Nueesch; F. T. Madsen

    2001-01-01

    Commonly used organophilic clays are modified by alkylammonium cations which hold apart the aluminosilicate layers permanently. The cations fill the interlayer space and are contemplated as flexible pillars, resulting from the mobility of the alkyl chains. Therefore, the interlayer distance varies depending on the layer charge and on the alkyl chain length. Contrary to these cations, rigid pillaring cations guarantee

  7. Rattles of Clay.

    ERIC Educational Resources Information Center

    Banning, Donna

    1983-01-01

    Using the rattles of Native American cultures as inspiration, students used pinching, coiling, and slab and molding techniques to form the bodies of rattles and clay pellets for sound. Surface decoration included glazed and unglazed areas as well as added handles, feathers, and leather. (IS)

  8. Moving Along: Sporting Clay.

    ERIC Educational Resources Information Center

    Hiller, Peter

    2002-01-01

    Presents a junior high school student art project where three-dimensional art sculptures of surfing, snow boarding, or dirt biking were created. Discusses how the students created their three-dimensional works of art using a clay-slab technique. (CMK)

  9. Minerals Yearbook

    NSDL National Science Digital Library

    According to the Minerals Yearbook Web site, the US Geological Survey Minerals Information Team's mission is to collect, analyze, and disseminate information on the domestic and international supply of and demand for minerals and mineral materials essential to the US economy and national security. The yearbook reviews the mineral and material industries of the United States and foreign countries, contains statistical data on materials and minerals, and includes information on economic and technical trends and development. Volume I contains metals and minerals information, volume II US area reports, and volume III international reports. A lot of data is presented in the various documents; thankfully, the site is organized well and easy to navigate.

  10. Ore Minerals

    NSDL National Science Digital Library

    Dexter Perkins

    This three part lab introduces sulfides and other ore minerals. Part one - Ore Minerals: Students fill in a table giving the metal, formula, and mineral group of several ore minerals. Part two - Box of Rocks: Students examine trays of ore minerals and record their physical properties, composition, habit, occurence, economic value, and use and answer questions about color, luster, density, transparency, and availability. Part three - Famous Digs: Students answer a series of questions related to famous ore deposits.

  11. CHEMICAL AND MINERALOGICAL CHARACTERISTICS OF FRENCH GREEN CLAYS USED FOR HEALING.

    PubMed

    Williams, Lynda B; Haydel, Shelley E; Giese, Rossman F; Eberl, Dennis D

    2008-08-01

    The worldwide emergence of infectious diseases, together with the increasing incidence of antibiotic-resistant bacteria, elevate the need to properly detect, prevent, and effectively treat these infections. The overuse and misuse of common antibiotics in recent decades stimulates the need to identify new inhibitory agents. Therefore, natural products like clays, that display antibacterial properties, are of particular interest.The absorptive properties of clay minerals are well documented for healing skin and gastrointestinal ailments. However, the antibacterial properties of clays have received less scientific attention. French green clays have recently been shown to heal Buruli ulcer, a necrotic or 'flesh-eating' infection caused by Mycobacterium ulcerans. Assessing the antibacterial properties of these clays could provide an inexpensive treatment for Buruli ulcer and other skin infections.Antimicrobial testing of the two clays on a broad-spectrum of bacterial pathogens showed that one clay promotes bacterial growth (possibly provoking a response from the natural immune system), while another kills bacteria or significantly inhibits bacterial growth. This paper compares the mineralogy and chemical composition of the two French green clays used in the treatment of Buruli ulcer.Mineralogically, the two clays are dominated by 1Md illite and Fe-smectite. Comparing the chemistry of the clay minerals and exchangeable ions, we conclude that the chemistry of the clay, and the surface properties that affect pH and oxidation state, control the chemistry of the water used to moisten the clay poultices and contribute the critical antibacterial agent(s) that ultimately debilitate the bacteria. PMID:19079803

  12. Characteristics of mineralogy and clay fabric on the petrophysical variation of the Southeastern Yellow Sea Mud (SEYSM), Korea

    NASA Astrophysics Data System (ADS)

    Narantsetseg, Buyanbat; Kim, Gil Young; Chang, Tae Su; Choi, Hun Soo; Kim, Jin Wook

    2013-04-01

    Velocity (compressional wave velocity) and physical properties were measured according to regular depth intervals for sixteen core sediments collected from Southeastern Yellow Sea Mud (SEYSM), Korea. The velocity for core samples was measured using the pulse transmission technique. Physical properties (water content, porosity, density) were measured using weight-volume method. Shear strength was manually measured by hand-vane apparatus. Overall, the muddy sediments with shells dominate in most cores, but the sandy sediments exist in the some depth intervals. Porosity (75?45%) and water content (90?50%) generally decrease with burial depth due to dewatering caused by overburden pressure. Thus the bulk density shows increasing trend (1.5?1.7 g/cm3) however, the grain density does not reflect regular patterns with depth. That is why grain density is determined depending on mineral composition. The velocity and shear strength generally increase with depth reflecting variation of other physical property data. The velocity abruptly decreases from 1480 m/s to 1349 m/s, in depth intervals from 310 cm to 400 cm of station P14. This is probably due to shallow gas within sediments and/or degassing cracks caused by escaped gas. Interestingly, porosity and water content below 90 cm depth of station P03 are significantly changed from 57% to 38% and from 55% to 23%, respectively. Also, the bulk density (1.56?2.04 g/cm3) and velocity (1571?1707 m/s) abruptly increase with burial depth. This is probably responsible for difference of sediment texture, caused by significant increase of sand contents. The sediments at stations P11 and P15 is likely more compacted and/or consolidated than those of stations P02, P03, P07, and P14. This is probably due to difference of compaction and/or consolidation after deposition and sedimentary processes related to sea level change. At stations P02, P03, P07, P11, and P15, X-ray diffractions reveal that the major clay minerals are chlorite, illite, chlorite+kaolinite, and kaolinite. Illite was identified as the most abundant clay mineral. The clay fabric analysis using scanning electron microscopy (SEM) was performed on splitter core samples (at core depth of 10 cm and 290 cm considering physical property data) of station P15. The clay fabric at 10 cm depth shows typical card-house structure and random arrangement of particles. And the clay particles have abundant edge-to-face (EF) and edge to edge (EE) contacts. The sediments at 290 cm depth of station P15 are characterized by decreased porosity (to 58%) and water content (to 36%). And wet bulk density and shear strength are gradually increased (1.65 g/cm3, 11 kPa). Accordingly the clay fabric shows well-oriented arrangements with dominant face-to face (FF) contacts, due to natural sediment compaction caused by overburden pressure.

  13. Proportions of coarse and fine clay across the Cretaceous-Tertiary boundary in Milam, Falls, and Travis Counties, Texas 

    E-print Network

    Smith, John Charles

    1966-01-01

    for the investigation Explanation of Proposed Method Location of Clay Units Investigated Previous Investigations Methods of Investigation Eield Investigations Laboratory Investigations Hesults of the lnvcstigation 15 26 Locality I Locality II Locality III... and fine clay expressed as percentages of the total clay i'rection from Locality I . 30 Lattice spacings, mineral composition, indices, and intensities of typical samples from Locality I 33 Proportions for duplicate fractionations of coarse and fine...

  14. Impact of desiccation on compressional and shear-wave velocities in clay-rocks: a laboratory study

    Microsoft Academic Search

    A. Ghorbani; M. Zamora; Ph. Cosenza

    2009-01-01

    The study of the impact of desiccation on the mechanical parameters of clay-rocks is of crucial importance to characterize the desaturated zone close to the walls of a deep underground repository, excavated into clay-rocks. Three core samples were taken from the Callovo-Oxfordian argillite formation located at the MHM-URL laboratory in Eastern France (40% of clay minerals in average); rich of

  15. Porous networks derived from synthetic polymer-clay complexes

    SciTech Connect

    Carrado, K.A.; Thiyagarajan, P.; Elder, D.L.

    1995-05-12

    Synthetic hectorites were hydrothermally crystallized with direct incorporation of a cationic polymer poly(dimethyl diallyl ammonium chloride) (PDDA), and two neutral cellulosic polymers hydroxypropyl methylcellulose (HPMC) and hydroxyethyl cellulose (HEC). Synthetic PDDA-hectorite displays the lowest d-spacing at 15.8 {Angstrom} along with less polymer incorporation (7.8 wt % organic) than the neutral polymers (18--22 wt % organic). Thermal analysis and small angle neutron scattering were used to further examine the polymer-clay systems. Clay platelets of the largest size and best stacking order occur when cationic PDDA polymer is used. PDDA also enhances these properties over the crystallites prepared for a control mineral, where no polymer is used. HEC acts to aggregate the silica, leaving less to react to form clay. The clay platelets which result from HEC are small, not stacked to a large degree, and oriented randomly. Neutral HPMC acts more like cationic PDDA in that larger clay platelets are allowed to form. The extended microstructure of the clay network remains undisturbed after polymer is removed by calcination. When no polymer is used, the synthetic hectorite has a N{sub 2} BET surface area of 200 M{sup 2}/gm, even after calcination. This increases by 20--50% for the synthetic polymer-hectorites after the polymer is removed by calcination.

  16. Removal of waterborne microorganisms by filtration using clay-polymer complexes.

    PubMed

    Undabeytia, Tomas; Posada, Rosa; Nir, Shlomo; Galindo, Irene; Laiz, Leonila; Saiz-Jimenez, Cesareo; Morillo, Esmeralda

    2014-08-30

    Clay-polymer composites were designed for use in filtration processes for disinfection during the course of water purification. The composites were formed by sorption of polymers based on starch modified with quaternary ammonium ethers onto the negatively charged clay mineral bentonite. The performance of the clay-polymer complexes in removal of bacteria was strongly dependent on the conformation adopted by the polycation on the clay surface, the charge density of the polycation itself and the ratio between the concentrations of clay and polymer used during the sorption process. The antimicrobial effect exerted by the clay-polymer system was due to the cationic monomers adsorbed on the clay surface, which resulted in a positive surface potential of the complexes and charge reversal. Clay-polymer complexes were more toxic to bacteria than the polymers alone. Filtration employing our optimal clay-polymer composite yielded 100% removal of bacteria after the passage of 3L, whereas an equivalent filter with granular activated carbon (GAC) hardly yielded removal of bacteria after 0.5L. Regeneration of clay-polymer complexes saturated with bacteria was demonstrated. Modeling of the filtration processes permitted to optimize the design of filters and estimation of experimental conditions for purifying large water volumes in short periods. PMID:25063930

  17. Metal precipitation in the Cretaceous-Tertiary boundary clay at Stevns Klint, Denmark

    NASA Astrophysics Data System (ADS)

    Schmitz, B.

    1985-11-01

    The theory that enrichment of the Fish Clay in Denmark occurs by the precipitation of metals at a geochemical barrier is proposed. The compositions of the layers of the Fish Clay are described, and a table of the elemental concentrations in the Fish Clay is provided. Data supporting the precipitation of elements as sulfides at the redoxcline include: (1) the chalcophile element abundance pattern in the Fish Clay; (2) the precipitation of metals at the anoxic-oxic boundary; and (3) the large amount of small pyrite spheroids at the redoxcline. A precipitation model depicting the process of elemental enrichment in the Fish Clay, based on metal-bearing pore solutions losing their metals by precipitation upon passing the boundary between the oxic Cretaceous chalk and the overlying anoxic and hydrogen sulfide-rich Fish Clay, is examined.

  18. Degradation of vanillin in soil-clay mixtures treated with simulated acid rain

    SciTech Connect

    Bewley, R.J.F.; Stotzky, G.

    1984-06-01

    Significant vanillin degradation occurred only in soil amended with 9% montmorillonite and not in soil amended with 9% kaolinite or in soil without addition of clay minerals. Progressively decreasing amounts of vanillin were mineralized in the montmorillonite-amended soil with increasing acidification with H/sub 2/SO/sub 4/, and complete inhibition of mineralization occurred at a soil pH of 1.6. 16 references, 1 table.

  19. Effect of iron diagenesis on the transport of colloidal clay in an unconfined sand aquifer

    SciTech Connect

    Ryan, J.N.; Gschwend, P.M. (Massachusetts Inst. of Tech., Cambridge (United States))

    1992-04-01

    The role of Fe diagenesis in the transport of clay colloids was investigated in the Cohansey Sand, an Fe(III) oxide-coated quartz arenite that covers most of the New Jersey Coastal Plain. Based on the authors' past work, they hypothesized that clay had been transported into the sediments, that the clay distribution was controlled by attachment to surface Fe(III) oxides, and that anoxic water infiltrating from a swamp had dissolved Fe(III) oxides and released clay colloids into flowing groundwater. Sediment cores were collected from upland and swamp terrains, and the composition and distribution of the clay-sized and heavy mineral fractions were examined by X-ray diffraction, optical and electron microscopy, separations, and elemental analyses. The clay-sized content of the oxidized sediments was roughly double that of the reduced sediments. Electron microscopy revealed that coatings on the quartz grains had the appearance of infiltrated clay particles. The relationship between clay and surface Fe content indicated that the onset of reducing conditions below the swamp remobilized clay colloids by dissolving Fe(III) oxide cement. Surface Fe(III) oxides were derived from weathering of ilmenite and pseudorutile, Fe-Ti oxides found in the heavy mineral fraction. In the oxidized sediments, Fe was transported from the Fe-Ti oxide grains to quartz surfaces, where it was deposited as surface Fe(III) oxides mixed with kaolinite. Thus, the weathering of Fe-bearing minerals and the formation and dissolution of secondary Fe(III) oxides influenced the mobility of colloidal clay in the Cohansey Sand.

  20. The nanophase iron mineral(s) in Mars soil

    NASA Technical Reports Server (NTRS)

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Mancinelli, R. L.; Gehring, A. U.

    1993-01-01

    A series of surface-modified clays containing nanophase (np) iron oxide/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these "Mars-soil analogs" were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging, specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The clay acted as an effective matrix, both chemically and sterically, preventing the major part of the synthesized iron oxides from ripening, i.e., growing and developing larger crystals. The precipitated iron oxides appear as isodiametric or slightly elongated particles in the size range 1-10 nm, having large specific surface area. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxy mineral such as "green rust," or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable maghemite (gamma-Fe2O3) by mild heat treatment and then to nanophase hematite (alpha-Fe2O3) by extensive heat treatment. After mild heating, the iron-enriched clay became slightly magnetic, to the extent that it adheres to a hand-held magnet, as was observed with Mars soil. The chemical reactivity of the iron-enriched clays strongly resembles, and offers a plausible mechanism for, the somewhat puzzling observations of the Viking biology experiments. Their unique chemical reactivities are attributed to the combined catalytic effects of the iron oxide/oxyhydroxides and silicate phase surfaces. The reflectance spectrum of the clay-iron preparations in the visible range is generally similar to the reflectance curves of bright regions on Mars. This strengthens the evidence for the predominance of nanophase iron oxides/oxyhydroxides in Mars soil. The mode of formation of these nanophase iron oxides on Mars is still unknown. It is puzzling that despite the long period of time since aqueous weathering took place on Mars, they have not developed from their transitory stage to well-crystallized end-members. The possibility is suggested that these phases represent a continuously on-going, extremely slow weathering process.

  1. Analysis of mineral matrices of planetary soil analogues from the Utah Desert

    NASA Astrophysics Data System (ADS)

    Kotler, J. M.; Quinn, R. C.; Foing, B. H.; Martins, Z.; Ehrenfreund, P.

    2011-07-01

    Phyllosilicate minerals and hydrated sulphate minerals have been positively identified on the surface of Mars. Studies conducted on Earth indicate that micro-organisms influence various geochemical and mineralogical transitions for the sulphate and phyllosilicate minerals. These minerals in turn provide key nutrients to micro-organisms and influence microbial ecology. Therefore, the presence of these minerals in astrobiology studies of Earth-Mars analogue environments could help scientists better understand the types and potential abundance of micro-organisms and/or biosignatures that may be encountered on Mars. Bulk X-ray diffraction of samples collected during the EuroGeoMars 2009 campaign from the Mancos Shale, the Morrison and the Dakota formations near the Mars Desert Research Station in Utah show variable but common sedimentary mineralogy with all samples containing quantities of hydrated sulphate minerals and/or phyllosilicates. Analysis of the clay fractions indicate that the phyllosilicates are interstratified illite-smectites with all samples showing marked changes in the diffraction pattern after ethylene glycol treatment and the characteristic appearance of a solvated peak at ˜17 Å. The smectite phases were identified as montmorillonite and nontronite using a combination of the X-ray diffraction data and Fourier-Transform Infrared Spectroscopy. The most common sulphate mineral in the samples is hydrated calcium sulphate (gypsum), although one sample contained detectable amounts of strontium sulphate (celestine). Carbonates detected in the samples are variable in composition and include pure calcium carbonate (calcite), magnesium-bearing calcium carbonate (dolomite), magnesium, iron and manganese-bearing calcium carbonate (ankerite) and iron carbonate (siderite). The results of these analyses when combined with organic extractions and biological analysis should help astrobiologists and planetary geologists better understand the potential relationships between mineralogy and microbiology for planetary missions.

  2. The interrelations of mineral colloids and sodium chloride as measured by pH, conductivity, and water-soluble cations 

    E-print Network

    Crozier, Baalis B

    1952-01-01

    TdovsaxoZsxaxyln 'syToe ~ pTolloo Iaxmrpa s%L QlOIXVD FKMOS HKfiVlL Gkii 'XuarzaaaaOO 'Hd IH GHHOSVHW SV HGIenaa WOIGOS GHV SGIOTIOD 'IVHXRIN LO HROIXVIRHHKQU KLT informtion vhich vill help identify the clay mineral or minerals present in Runt clays a rather... of the various clay minerals that exist in soils, it is quite possible that dii'ferent soil colloids under identical treatments vill react differently. Many of ths physical and chemical properties of soils are 4ependent, upon the surface activity of the clay...

  3. Structure-related geochemical (REE) and isotopic (K-Ar, Rb-Sr, {delta}{sup 18}O) characteristics of clay minerals from Rotliegend sandstone reservoirs (Permian, northern Germany)

    SciTech Connect

    Zwingmann, H.; Clauer, N.; Gaupp, R.

    1999-09-01

    Euhedral illite cementing the gas-bearing sandstone reservoirs of the Rotliegend in the Niedersaechsische rift system (northern Germany) was studied along a horst-to-graben cross-section to examine its chemical and isotopic characteristics. The data show that differentiated illite particles grew during a tectono-thermal event marked by distinct episodic hydrothermal activities along fault drains and in the poral space of sandstones at 210 Ma and at 195 to 190 Ma in horst positions, at 185 to 175 Ma in the nearby graben, and at 170 to 165 Ma in both the horst and graben. Varied REE distribution patterns and initial {sup 87}Sr/{sup 86}Sr ratios (from 0.7124 to 0.7142) relative to illite-particle size outline a high chemical variability of the fluids during illite growth. The {delta}{sup 18}O values of illite range from +20.0 to +12.4% and those of chlorite from +12.0 to +6.9%. The changing {delta}{sup 18}O values of the minerals most likely relate to varied {delta}{sup 18}O values of the fluids, or to different water/rock ratios during crystallization. Differences among the REE and {sup 87}Sr/{sup 86}Sr tracers and the {delta}{sup 18}O values of different generations of illite also suggest a changing fluid chemistry relative to time. significant positive Eu anomalies and negative Ce anomalies in the REE distributions of illite suggest feldspar alteration by the migrating fluids in oxidizing environments.

  4. Mineral Classification

    NSDL National Science Digital Library

    This problem set challenges students to determine the chemical classification of minerals based on their chemical formula (provided). For oxygen-bearing minerals, students must also provide the valences of the various cations.

  5. Chemical weathering on Mars - Thermodynamic stabilities of primary minerals /and their alteration products/ from mafic igneous rocks

    NASA Technical Reports Server (NTRS)

    Gooding, J. L.

    1978-01-01

    Chemical weathering on Mars is examined theoretically from the standpoint of thermodynamic equilibrium between primary rock-forming minerals and the atmospheric gases O2, H2O, and CO2. The primary minerals considered are those common to mafic igneous rocks and include olivine, pyroxene, plagioclase, magnetite, troilite, pyrrhotite, and apatite. The importance of kinetics and reaction mechanisms in controlling possible weathering processes on Mars is discussed within the limits of currently available data, and the possible influence of liquid water on Martian weathering processes is evaluated where appropriate. For gas-solid weathering of mafic igneous rocks at the Martian surface, it is concluded that upon attainment of thermodynamic equilibrium: (1) oxides and carbonates should dominate the mineral assemblage of weathering products; (2) hematite rather than goethite should be the stable mineral form of Fe (III); (3) FeSO4 or FeSO4.H2O could be the stable weathering product of iron sulfides in the absence of liquid water; and (4) kaolinite is apparently the only clay mineral that should be thermodynamically stable over all ranges of temperature and water-vapor abundance at the Martian surface.

  6. Mineral Chart

    MedlinePLUS

    ... Dynamic Stretching A Guy's Guide to Body Image Mineral Chart KidsHealth > Teens > Miscellaneous > Mineral Chart Print A A A Text Size Type ... sources of calcium. You'll also find this mineral in broccoli and dark green, leafy vegetables. Soy ...

  7. Mineral Properties

    NSDL National Science Digital Library

    Mineralogy 4 Kids

    This site from the Mineralogical Society of America describes the physical properties of minerals in terms that kids will understand. The site also includes the definition of a mineral, an identification chart, and links to descriptions of the physical properties used to identify minerals.

  8. [Kinetics and mechanism of removing Microcystis aeruginosa using clay flocculation].

    PubMed

    Pan, Gang; Zhang, Mingming; Yan, Hai; Zou, Hua; Chen, Hao

    2003-09-01

    Twenty-six natural clays were studied for their kinetics of flocculating and removing algal cells of Microcystis aeruginosa. According to the 8 h equilibrium removal efficiencies and removal rates at a clay-loading of 0.7 g.L-1, all the 26 clays were classified into three categories. Type-I clay, which includes talc, ferric oxide, sepiolite, ferroferric oxide, and kaolinite, has an equilibrium removal efficiency greater than 90%, a t50 (time needed to remove 50% of the algae) of less than 30 min, and a t80 (time needed to remove 80% of the algae) of less than 2.5 h. Type-II clay, which includes argillanceous rocks, attapulgite, rectorite, illite, and argil, etc., has an equilibrium removal efficiency of 50%-80%, a t50 of less than 2.5 h, and a t80 of more than 5 h. Type-III clay consists of 14 minerals, including laterite, zeolite, mica, clinoptilolite, pumice, tripoli, feldspar and quartz, etc. with the removal efficiency less than 50%, and t50 > > 8 h. When the clay loading was decreased to 0.1-0.2 g.L-1, the 8 h equilibrium removal efficiencies for 25 clays declined to below 60%, except for sepiolite, a Type-I clay, which maintained around 90%. After the sepiolite was modified with Fe3+ to increase its surface charge (Zeta potential from -24.0 mV to +0.43 mV at pH 7.4), the initial removal rate was increased remarkably although its 8 h equilibrium removal efficiency was not improved substantially. As a comparison, the 8 h equilibrium removal efficiency of PAC was no greater than 40% at loadings of 0.02-0.2 g.L-1. Following the analysis of the flocculation mechanism it was concluded that the effect of bridging and netting may play a key role in the clay-algae flocculation processes, which may be important for selecting and modifying clays to improve significantly the removal efficiency. PMID:14719252

  9. ABIOTIC ORGANIC REACTIONS AT MINERAL SURFACES

    EPA Science Inventory

    Abiotic organic reactions, such as hydrolysis, elimination, substitution, redox, and polymerization reactions, can be influenced by surfaces of clay and primary minerals, and of metal oxides. This influence is due to adsorption of the reactants to surface Lewis and Bronsted sites...

  10. Provenance of Late Cretaceous to Paleocene submarine fan sandstones in the Norwegian Sea: Integration of heavy mineral, mineral chemical and zircon age data

    Microsoft Academic Search

    A. C. Morton; A. G. Whitham; C. M. Fanning

    2005-01-01

    This paper describes a strategy for effective discrimination and provenance evaluation of sandstones transported by different sediment dispersal systems using an integrated programme of heavy mineral analysis, mineral chemistry and zircon age dating. Sandstones derived from different source regions are initially discriminated using provenance–sensitive heavy mineral parameters (ratios of abundances of stable, hydraulically equivalent minerals). Differences between the heavy mineral

  11. Functionalized synthetic clays designed for polymer-clay nanocomposites

    NASA Astrophysics Data System (ADS)

    Chastek, Thuy Truong

    Polymer-clay nanocomposites have many advantageous properties such as their light weight, transparency, flame retardency, barrier properties, and low cost. Exfoliation of natural clays into commercially important non-polar polymers such as polystyrene (PS) and polypropylene (PP) melts has been limited due to the immiscibility of these polymers with highly polar clays. Current means of addressing this problem, such as treating clays with surfactants, has met with limited success. Motivated by the need for synthetic clays that can be dispersed and exfoliated in non-polar polymer melts without added compatibilizers, we synthesized lamellar silicates and aluminosilicates to act as clay analogs. The flexibility of the sol-gel syntheses allowed hexadecyl and isobutyl functional groups to be covalently attached to the surface of the clays. Incorporating a high content of octahedral aluminum also strengthened the clay layers. The strength and surface functionalities of the layered silicates improved exfoliation during melt blending with PS and PP. We studied the effects of clay layer composition (silicate and alumino-silicate), layer thickness, organic functional groups, aluminum coordination, and covalent linking of surfactants on the performance of the nanocomposites. The lamellar morphology was determined from XRD and TEM. Organic functionalization was determined with solid state NMR and IR spectroscopy. The synthetic clays were mixed with various solvents to help predict their miscibility with PS and PP. Composites were prepared with different molecular weight polymers, which subjected the clays to a wide range of shear stresses. The clays were also pretreated by mixing in a master batch or dispersing in an organic solvent. The effects of PS and PP molecular weight, master batch, and solvent dispersion on the exfoliation of synthetic clays in PS are examined. Rheology and TEM were used to observe the quality of exfoliation and the final aspect ratio of the clay layers in the PS- or PP-nanocomposites. A different type of synthetic clay, potassium niobate (K4Nb 6O17), which has a layered structure formed from crystalline niobate sheets was synthesized and mixed with PMMA latex. The exfoliated layered niobates were found to disperse well in PMMA latex.

  12. Alteration of cameroonian clays under acid treatment. Comparison with industrial adsorbents

    Microsoft Academic Search

    J. P. Nguetnkam; R. Kamga; F. Villiéras; G. E. Ekodeck; A. Razafitianamaharavo; J. Yvon

    2011-01-01

    In view to evaluate an alternative local cheaper source for vegetable oil refiners, three cameroonian clays containing swelling (smectites) and non-swelling (kaolinite) clay minerals were treated with sulphuric acid solutions at concentrations of 1, 2, 4 and 8N at 80°C for 2h. Their alteration and resulting products were characterized by XRD, FT-IR-spectroscopy, chemical analyses, along with TEM-EDS, nitrogen adsorption isotherms

  13. Characterisation of Kaolinitic Clays from the Ivory Coast: Identification of Structural Fe

    Microsoft Academic Search

    J. Sei; A. Abba Touré; J. Olivier-Fourcade; H. Quiquampoix; S. Staunton; J. C. Jumas; M. Womes

    2004-01-01

    Five clays from four different deposits in the Ivory Coast (Adattié, Nieki, Grand-Bassam, Nigui-Saff) were studied by 57Fe Mössbauer spectroscopy and electron paramagnetic resonance (EPR) at room temperature. Their chemical compositions were\\u000a determined by X-ray fluorescence and the most important crystalline phases were identified by X-ray diffraction. In these\\u000a natural clays, kaolinite is the dominant mineral phase with minor amounts

  14. Sedimentary processes on the Bengal continental shelf as revealed by clay-size mineralogy

    Microsoft Academic Search

    M. P. Segall; S. A. Kuehl

    1992-01-01

    Shelf sediment dispersal seaward of the Ganges-Brahmaputra river system is examined during January\\/February (low discharge) through analysis of sediment cores and surface grab samples for clay-size mineralogy. Illite is the dominant mineral in surficial sediments landward of the 50-m isobath, comprising >40% of the clay-size assemblage. Kaolinite concentrations of surficial sediments generally are greater than 20% throughout the area; however,

  15. CLAY AND SHALE--2001 18.1 CLAY AND SHALE

    E-print Network

    and miscellaneous ceramics (14%), sanitaryware (22%), and floor and wall tile (35%) for ball clay; absorbents (25 of lightweight aggregate, brick and structural clay products, and ceramics. The EPA was developing a standard of slimes and dust control is usually required. The rules for disposal of coarse tailings are similar

  16. Mineral magnetic and geochemical records of late Glacial climatic change from two northwest European carbonate lakes

    Microsoft Academic Search

    S. R. Nolan; J. Bloemendal; J. F. Boyle; R. T. Jones; F. Oldfield; M. Whitney

    1999-01-01

    We present the results of mineral magnetic measurements and geochemical analyses of late Glacial sediments from two marl-precipitating lakes in the Northwest of England. Mineral magnetic assemblages dominated by detrital and\\/or authigenic ferrimagnetic minerals, and enhanced delivery of metal elements, characterise a lower (Oldest Dryas) and an upper (Younger Dryas) phase of catchment instability, with detrital clay and silt sedimentation.

  17. Multiscale modeling of clay-water systems

    E-print Network

    Ebrahimi, Davoud

    2014-01-01

    The engineering properties of soils are highly affected by clay content and clay-water interactions. However, existing macro-scale continuum models have no length scale to describe the evolution of the clay microstructure ...

  18. Direct visualization of clay microfabric signatures driving organic matter preservation in fine-grained sediment

    NASA Astrophysics Data System (ADS)

    Curry, Kenneth J.; Bennett, Richard H.; Mayer, Lawrence M.; Curry, Ann; Abril, Maritza; Biesiot, Patricia M.; Hulbert, Matthew H.

    2007-04-01

    We employed direct visualization of organic matter (OM) sequestered by microfabric signatures in organo-clay systems to study mechanisms of OM protection. We studied polysaccharides, an abundant class of OM in marine sediments, associated with the nano- and microfabric of clay sediment using a novel application of transmission electron microscopy, histochemical staining (periodic acid-thiosemicarbazide-silver proteinate), and enzymatic digestion techniques. We used two experimental organo-clay sediment environments. First, laboratory-consolidated sediment with 10% chitin (w/w) added was probed for chitin before and after digestion with chitinase. Second, fecal pellets from the polychaete Heteromastus filiformis were used as a natural environment rich in clay and polysaccharides. Sections of this material were probed with silver proteinate for polysaccharides before and after digestion with a mixture of enzymes (amylase, cellulase, chitinase, dextranase, and pectinase). In both environments, chitin or other polysaccharides were found within pores, bridging clay domains, and attached to clay surfaces in undigested samples. Digested samples showed chitin or polysaccharides more closely associated with clay surfaces and in small pores. Our results imply protective roles for both sorption to clay surfaces and encapsulation within clay microfabric signatures.

  19. Attenuation of pollutants in municipal landfill leachate by passage through clay

    USGS Publications Warehouse

    Griffin, R.A.

    1976-01-01

    To evaluate the potential of clay minerals for attenuating the various chemical constituents of landfill leachate, leachate was passed through laboratory columns that contained various mixtures of calcium-saturated clays and washed quartz sand. Leachates were run through the columns for periods of up to 10 months, during which time effluents were periodically collected and analyzed for 16 chemical constituents. Chloride, Na, and water-soluble organic compounds (COD) were poorly attenuated by passage through the clay columns; K, NH4, Mg, Si, and Fe were moderately attenuated; and heavy metals such as Pb, Cd, Hg, and Zn were strongly attenuated by even small amounts of clay. Concentrations of Ca, B, and Mn in the column effluents increased markedly over the original leachate concentrations. Of the three clays used in the study, montmorillonite had the highest attenuation capability, followed by illite and then kaolinite. Attenuation was a function of the CEC of the clay mineral, the initial exchangeable cations on the clay, the chemical composition of the leachate, and the pH of the leachate.

  20. Analysis of clay layer compression

    NSDL National Science Digital Library

    Charlie Fitts

    Students analyze time series data for long-term ground subsidence in response to dewatering. From this analysis, the students can back-figure the compressibility of a clay lens that is compressing, and the vertical hydraulic conductivity of the clay. The data may be downloaded from the book web site and imported into a spreadsheet for analysis.

  1. Persulfate activation by subsurface minerals

    NASA Astrophysics Data System (ADS)

    Ahmad, Mushtaque; Teel, Amy L.; Watts, Richard J.

    2010-06-01

    Persulfate dynamics in the presence of subsurface minerals was investigated as a basis for understanding persulfate activation for in situ chemical oxidation (ISCO). The mineral-mediated decomposition of persulfate and generation of oxidants and reductants was investigated with four iron and manganese oxides and two clay minerals at both low pH (< 7) and high pH (> 12). The manganese oxide birnessite was the most effective initiator of persulfate for degrading the oxidant probe nitrobenzene, indicating that oxidants are generated at both low and high pH regimes. The iron oxide goethite was the most effective mineral for degrading the reductant probe hexachloroethane. A natural soil and two soil fractions were used to confirm persulfate activation by synthetic minerals. The soil and soil fractions did not effectively promote the generation of oxidants or reductants. However, soil organic matter was found to promote reductant generation at high pH. The results of this research demonstrate that synthetic iron and manganese oxides can activate persulfate to generate reductants and oxidants; however, iron and manganese oxides in the natural soil studied do not show the same reactivity, most likely due to the lower masses of the metal oxides in the soil relative to the masses studied in isolated mineral systems.

  2. Mineral Identification

    NSDL National Science Digital Library

    John Pratte

    This lesson discusses the question 'What is a mineral?' in the context of the guessing game 'Animal, Vegetable, or Mineral?'. It introduces a definition of the term, discusses the criteria used in the definition, and presents the common physical properties used in mineral identification. The lesson includes an activity in which students observe and record the physical properties of ten specimens and attempt to identify them using an online reference for practice.

  3. Can clays ensure nuclear waste repositories?

    NASA Astrophysics Data System (ADS)

    Zaoui, A.; Sekkal, W.

    2015-03-01

    Research on argillite as a possible host rock for nuclear waste disposal is still an open subject since many issues need to be clarified. In the Underground Research Laboratories constructed for this purpose, a damaged zone around the excavation has been systematically observed and characterized by the appearance of micro-fissures. We analyse here -at nanoscale level- the calcite/clay assembly, the main constituents of argillite, under storage conditions and show the fragility of the montmorillonite with respect to calcite. Under anisotropic stress, we have observed a shear deformation of the assembly with the presence of broken bonds in the clay mineral, localised in the octahedral rather than the tetrahedral layers. The stress/strain curve leads to a failure strength point at 18.5 MPa. The obtained in-plane response of the assembly to perpendicular deformation is characterized by smaller perpendicular moduli Ez = 48.28 GPa compared to larger in-plane moduli Ex = 141.39 GPa and Ey = 134.02 GPa. Our calculations indicate the instability of the assembly without water molecules at the interface in addition to an important shear deformation.

  4. Can corn plants inoculated with arbuscular mycorrhiza fungi affect soil clay assemblage?

    NASA Astrophysics Data System (ADS)

    Adamo, P.; Cozzolino, V.; Di Meo, V.; Velde, B.

    2012-04-01

    Plants can extract K from exchangeable and non-exchangeable sites in the soil clay mineral structures. The latter, known as fixed K, is usually seen as an illite layer, i.e. an anhydrous K layer that forms a 1.0 nm structural layer unit as seen by X-ray diffraction. Nutrient availability can be enhanced in the root zone by arbuscular mycorrhiza fungi. In this study, the effects of non-inoculated and Glomus intraradices inoculated corn plant growth under different experimental conditions on soil K-bearing clay minerals were identified. The soil, a Vertic Xerofluvent, was planted in corn in a 2008-2010 randomized field experiment. Bulk and rhizosphere soil sampling was carried out from May to September 2010 from fertilized plots (N200P90K160 and N200P0K160) with and without plants. According to XRD analysis, three major K-bearing minerals were present in soil: smectite-rich mixed layer mineral, illite-rich mixed layer mineral and illite. Results at 40DAS indicate extraction of K from clay minerals by plant uptake, whereas at 130DAS much of the nutrient seems to be returned to the soil. There is an apparent difference between bulk and rhizophere clays. The XRD patterns are not unequivocally affected by Glomus inoculation. There are observable changes in clay mineralogy in fallow unfertilized compared with fertilized soil. In the studied soil, the illite rich mixed-layer minerals seem to be the source of K absorbed by plants, while illite acts as sink of K released from the plant-microorganisms system at the end of the growing season and as source for the following crop.

  5. The nanosphere iron mineral(s) in Mars soil

    NASA Technical Reports Server (NTRS)

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Mancinelli, R. L.; Gehring, A. U.

    1993-01-01

    A series of surface-modified clays containing nanophase (np) iron/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these 'Mars-soil analogs' were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxyl mineral such as 'green rust', or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable meaghemite (gamma-Fe203) by mild heat treatment and then to nanophase hematite (aplha-Fe203) by extensive heat treatment. Their chemical reactivity offers a plausible mechanism for the somewhat puzzling observations of the Viking biology experiments. Their unique chemical reactivities are attributed to the combined catalytic effects of the iron oxide/oxyhydroxide and silicate phase surfaces. The mode of formation of these (nanophase) iron oxides on Mars is still unknown.

  6. Mineral Densities

    NSDL National Science Digital Library

    Students are given cubic cell edge dimensions and asked to calculate mineral densities and vice versa. The final question of this homework assignment provides students with a mineral density and unit cell edge length in order to determine the number of formula units per cell.

  7. Mineral Identification

    NSDL National Science Digital Library

    Michael Passow

    In this activity, students use written and online materials to answer a set of questions on the general properties and identification of minerals. They will learn about physical properties such as color, hardness, and cleavage; special properties such as fluorescence and effervescence; and complete a chart listing properties for a selection of minerals. Links to the necessary information are provided.

  8. Industrial Minerals.

    ERIC Educational Resources Information Center

    Brady, Lawrence L.

    1983-01-01

    Discusses trends in and factors related to the production of industrial minerals during 1982, indicating that, as 1981 marked a downturn in production of industrial minerals, 1982 continued the trend with temporary and permanent cutbacks in mine and plant production. Includes highlights of several conferences/conference papers in this field.…

  9. Mineral Hunt

    NSDL National Science Digital Library

    2012-06-26

    In this activity, learners search for various kinds of items made from minerals around their home or school, including toothpaste, wall paint, kitty litter, and bricks. The PDF contains a check off list as well as recommended sites for more information on minerals.

  10. Mystery Minerals

    NSDL National Science Digital Library

    Susan Morgan

    In this activity, students will discover that minerals have specific characteristics that help to identify them. They will learn that minerals are formed by inorganic processes, are crystalline solids with an internal orderly arrangement of atoms, have specific chemical compositions, and have specific physical and chemical characteristics. They will also learn that minerals are commonly identified by the physical properties they possess, such as hardness, color, crystal shape, specific gravity, and streak. In addition, they will discover some other useful properties such as reaction with hydrochloric acid or a characteristic taste. They should also understand that color is not always a useful property for identifying minerals because it can vary. The students will also develop listening and observational skills and learn the uses of a few common minerals.

  11. Mineral resource of the month: magnesium

    USGS Publications Warehouse

    Kramer, Deborah A.

    2012-01-01

    Magnesium is the eighthmost abundant element in Earth’s crust, and the second-most abundant metal ion in seawater. Although magnesium is found in more than 60 minerals, only brucite, dolomite, magnesite and carnallite are commercially important for their magnesium content. Magnesium and its compounds also are recovered from seawater, brines found in lakes and wells, and bitterns (salts).

  12. Comparison of Floc Growth and Stability in Four Estuarine Clay Simulations

    NASA Astrophysics Data System (ADS)

    Reed, A. H.; Smith, J. P.; Gurzynski, W.; Zhang, G.

    2014-12-01

    Flocculated sediment transport is a primary determinant of hydrodynamics and geomorphology in many muddy nearshore environments which contain significant amounts of clay. In these nearshore and estuarine environments, as in most oceanic environments, the clay mineral occurrence is dominated by the following: montmorillonite (2:1 expandable), illite (2:1 non-expandable) and kaolinite (1:1 non-expandable). However, the percentages of clay minerals within these environments vary significantly. This work addresses the importance of clay mineral percentages on floc growth rates and stability. A series of analyses used four different ratios of montmorillonite, illite and kaolinite; these ratios serve to simulate the clay mineral assemblage in four different rivers. The clay minerals were mixed into saline water within which guar, a nonionic biopolymer, had previously been dissolved. Upon addition, the mixture was shaken vigorously for several minutes and then the system was allowed to settle into a quiescent environment. Flocs were maintained in a quiescent, no-flow environment until analyzed. The analyses consisted of subjecting the flocs to three flow rates within a flow through particle size analyzer, CILAS1190. For each flow rate, floc sizes were quantified and stability was inferred from changes in floc size. The flocs were analyzed during a two month period; assessments were made after 1d, 2d, 7d, 14d, 1m and 2m from the initial mixing. Results indicate that while floc size increased significantly over time, total floc stability changed less significantly. This work suggests that floc growth and stability may be achieved in a relatively short duration of time within quiescent environments. The importance of hydrodynamic stress on floc size and stability will be an important aspect for future research; subjecting flocs to hydrodynamic stress will address the importance of particle collisions and fluid-induced stress on floc size and stability.

  13. USING A MINERAL AGGREGATE TO SUPPLY PHOSPHORUS AND POTASSIUM FOR CONTAINERIZED CROP PRODUCTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is a rising need for increased water and nutrient use efficiency in ornamental container production to maximize profits while minimizing environmental impact. Substrates containing industrial mineral aggregates (clay) can increase water use efficiency and reduce phosphate leaching while retain...

  14. Early diagenetic formation of illite: implications for clay geothermometry

    SciTech Connect

    Fishman, N.S.; Turner-Peterson, C.E.; Owen, D.E.

    1987-05-01

    A concentric zonation of authigenic clays occurs in altered tuff beds deposited in saline-alkaline playa-lake complex that represents the Brushy Basin Member of the Upper Jurassic Morrison Formation in the eastern part of the Colorado Plateau. Along the margins of the playa-lake complex, randomly ordered smectitic mixed-layer clays (80-100% expandable layers) formed upon alteration of silicic volcanic ash. In contrast, stratigraphically equivalent altered tuff beds in the central part of the playa-lake complex contain ordered illitic mixed-layer clays (0-30% expandable layers). This pattern of a basinward increase in illitic layers coincides with the concentric zonation of authigenic minerals in tuff beds from smectite and clinoptilolite (playa margin) to analcime, K-feldspar, and albite (central playa). Temperatures above 90/sup 0/C have been considered necessary for transforming randomly ordered smectitic clays to ordered illitic phases. (It remains unclear whether illitic phases can precipitate directly from solution.) In the Brushy Basin Member, however, zonation of clays occurs irrespective of proximity to sources of heat (intrusive and extrusive igneous bodies) and depth of burial. Instead, the basinward increase in salinity and alkalinity of syndepositional pore waters, which is indicated by the zonation of authigenic zeolites and feldspars in Brushy Basin tuff beds, probably also controlled the basinward increase in illitic content of mixed-layer phases. Thus, illitization possibly resulted from early transformation of precursor clays, or alternatively, by early, direct precipitation. Because pore waters at near-surface temperatures can seemingly control formation of illitic phases, caution should be exercised when using illite as a geothermometer to evaluate the thermal evolution of sedimentary sequences.

  15. Role of organic modifiers on the enhancement of nanochemical properties of clay-based nanocomposites: A nanoscale experimental and multiscale modeling study

    Microsoft Academic Search

    Debashis Sikdar

    2007-01-01

    Polymer clay nanocomposite (PCN) is a novel composite material which is synthesized by mixing expansive clay minerals with polymeric materials in the nanometer length scale. In this research, we have found the mechanisms responsible for enhanced mechanical properties in PCN in comparison to pristine polymer. Photoacoustic (PA) Fourier transform infrared spectroscopy (FTIR) of PCN shows that there are only nonbonded

  16. Interactions of mineral dust with pollution and clouds: An individual-particle TEM study of atmospheric aerosol from Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Pósfai, Mihály; Axisa, Duncan; Tompa, Éva; Freney, Evelyn; Bruintjes, Roelof; Buseck, Peter R.

    2013-03-01

    Aerosol particles from desert dust interact with clouds and influence climate on regional and global scales. The Riyadh (Saudi Arabia) aerosol campaign was initiated to study the effects of dust particles on cloud droplet nucleation and cloud properties. Here we report the results of individual-particle studies of samples that were collected from an aircraft in April 2007. We used analytical transmission electron microscopy, including energy-dispersive X-ray spectrometry, electron diffraction, and imaging techniques for the morphological, chemical, and structural characterization of the particles. Dust storms and regional background conditions were encountered during four days of sampling. Under dusty conditions, the coarse (supermicrometer) fraction resembles freshly crushed rock. The particles are almost exclusively mineral dust grains and include common rock-forming minerals, among which clay minerals, particularly smectites, are most abundant. Unaltered calcite grains also occur, indicating no significant atmospheric processing. The particles have no visible coatings but some contain traces of sulfur. The fine (submicrometer) fraction is dominated by particles of anthropogenic origin, primarily ammonium sulfate (with variable organic coating and some with soot inclusions) and combustion-derived particles (mostly soot). In addition, submicrometer, iron-bearing clay particles also occur, many of which are internally mixed with ammonium sulfate, soot, or both. We studied the relationships between the properties of the aerosol and the droplet microphysics of cumulus clouds that formed above the aerosol layer. Under dusty conditions, when a large concentration of coarse-fraction mineral particles was in the aerosol, cloud drop concentrations were lower and droplet diameters larger than under regional background conditions, when the aerosol was dominated by submicrometer sulfate particles.

  17. Hydration Energy Determines Isovalent Cation Exchange Selectivity by Clay Minerals

    Microsoft Academic Search

    Brian J. Teppen; David M. Miller

    2006-01-01

    Cation exchange is one of the most venerable concepts in soil science, yet it needs rethinking. This paper presents an extremely simple conceptual framework for interpreting many observed trends in cation exchange. Taking the example of Cs-K exchange, the methods of computational molecular mechanics found that Cs-montmorillonite is considerably higher in energy than K-montmorillonite at constant water content, in agreement

  18. Sorption of the herbicide aminocyclopyrachlor by cation modified clay minerals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aminocyclopyrachlor is a newly registered herbicide for the control of broadleaf weeds, grasses, vines and woody species in non-crops, turf, sod farms, and residential areas. At typical soil pH levels, aminocyclopyrachlor is in the anionic form. Anionic pesticides are generally weakly retained by mo...

  19. Cesium Adsorption on Clay Minerals: An EXAFS Spectroscopic

    E-print Network

    Chorover, Jon

    of the influence of Cs loading and exchange- ability on this structural arrangement, we could recognize both inner for exploring the type of Cs binding in environmental samples. Introduction radionuclides is controlled by their sorption onto soil particles (4-6). A variety of factors, including

  20. Study of asphaltenes adsorption onto different minerals and clays

    Microsoft Academic Search

    Dorota Dudášová; Geir Rune Flåten; Johan Sjöblom; Gisle Øye

    2009-01-01

    In gas and oil production, produced water usually contains dispersed solids along with dissolved and dispersed oil. Solids are of reservoir origin as well as corrosion products (e.g. Fe3O4 from pipelines) and waste products of bacterial metabolic activities (e.g. FeS) under anaerobic conditions. These particles are coated with surface active components upon contact with oil. In the present paper we

  1. Occurrence and alteration of clay minerals in the Caribbean Sea 

    E-print Network

    Johnson, Charles Michael

    1973-01-01

    . The + formation of kaolinite or chlorite from gibbsite would also be con- sidered a form of diagenesis. Location of ~Stud The Magdalena River in Colombia drains the northern edge of the Andes Mountains and is the only major river emptying into the Caribbean... of Texas ASM University. The grab sample was taken from within the Magdalene River. This sample represents sediment typical of that brought into the Caribbean by the bed load of the Magdalena River. Five piston cores were taken along a tran- sect from...

  2. Potassium Fixation and Supply by Soils with Mixed Clay Minerals

    E-print Network

    Hipp, Billy W.

    1969-01-01

    OF THE SOILS USED IN THE STUDY were grown from 30 to 32 days, but plants of en all pots were allowed to grow the same length of crop was harvested at the end of the growth period i-: ting the entire plant at soil level. The plants merc rl;.. distilled...

  3. Degradation of Nitrobenzene Using Bio-Reduced Fe-Clays: Progress Towards the Development of an in-situ Groundwater Remediation Technology

    NASA Astrophysics Data System (ADS)

    White, M. L.; Fialips, C. I.

    2008-12-01

    Clay minerals are widely used in agricultural, industrial and environmental engineering applications due to their specific physical and chemical properties and their high abundance in soils in sediments. Currently however, Fe-bearing clays are not widely exploited in these applied fields. Fe-rich smectites, such as nontronite, can contain up to 20wt% of Fe2O3 as structural Fe(III) and if a suitable electron donor is available, this Fe(III) can be utilized by Fe-reducing bacteria as a terminal electron acceptor. When reduced, the overall reactivity of Fe-smectites changes, particularly where interactions with water and various organic compounds are involved. For instance, the presence of reduced Fe-smectites has been found to induce the degradation of certain organic contaminants found in groundwaters and the subsurface, e.g. chlorinated aliphatics and nitroaromatic compounds. The goal of this study is to develop an in-situ groundwater remediation technology that targets redox- sensitive organics, in the form of a permeable Bio Fe-clay barrier. To achieve this, the iron-reducing bacterium Shewanella algae BrY was first used to reduce structural FeIII in <2micron fractions of the Fe- rich smectite nontronite (NAu-2, 41.74wt% Fe2O3) and a Fe-bearing montmorrillonite (Speeton Clay, Yorkshire, UK, ~8wt% Fe2O3). S. algae BrY was able to reduce structural FeIII within these clays to maximum Fe(II)/Fe(II)+Fe(III) ratios 0.34 and 0.19 for the nontronite and Speeton Clay, respectively, in the presence and absence of the electron shuttle, AQDS (9, 10-anthraquinone-2, 6-disulfonic acid). These results are novel because the capability of S. algae BrY to reduce structural Fe(III) in smectite clays has not previously been tested. Nitrobenzene was selected as the test redox-sensitive organic compound as it is a common subsurface contaminant and is of global ecotoxicological concern. To test the capability of bio- reduced Fe-clays to transform nitrobenzene to aniline (the less toxic and more stable degradation product of nitrobenzene), nontronite suspensions with reduction levels of 20% and 30% were spiked with various concentrations of nitrobenzene and monitored for 5 days. Results showed that when reduced clay, S. algae BrY and AQDS were present, 100% of the nitrobenzene had been transformed to aniline within 24 hours. Further recent results suggest that bio-reduced nontronite alone is also capable of degrading nitrobenzene but at a slower rate than when AQDS is present. Future experiments will constrain absorption and degradation rates of nitrobenzene in contact with the reduced Fe-clays and the role(s) of the Fe-reducing bacteria. Results to date will be presented.

  4. Clay mineralogy of surface sediments as a tool for deciphering river contributions to the Cariaco Basin (Venezuela)

    NASA Astrophysics Data System (ADS)

    Bout-Roumazeilles, V.; Riboulleau, A.; ChâTelet, E. Armynot; Lorenzoni, L.; Tribovillard, N.; Murray, R. W.; Müller-Karger, F.; Astor, Y. M.

    2013-02-01

    The mineralogical composition of 95 surface sediment samples from the Cariaco Basin continental shelf and Orinoco delta was investigated in order to constrain the clay-mineral main provenance and distribution within the Cariaco Basin. The spatial variability of the data set was studied using a geo-statistical approach that allows drawing representative clay-mineral distribution maps. These maps are used to identify present-day dominant sources for each clay-mineral species in agreement with the geological characteristics of the main river watersheds emptying into the basin. This approach allows (1) identifying the most distinctive clay-mineral species/ratios that determine particle provenance, (2) evaluating the respective contribution of local rivers, and (3) confirming the minimal present-day influence of the Orinoco plume on the Cariaco Basin sedimentation. The Tuy, Unare, and Neveri Rivers are the main sources of clay particles to the Cariaco Basin sedimentation. At present, the Tuy River is the main contributor of illite to the western part of the southern Cariaco Basin continental shelf. The Unare River plume, carrying smectite and kaolinite, has a wide westward propagation, whereas the Neveri River contribution is less extended, providing kaolinite and illite toward the eastern Cariaco Basin. The Manzanares, Araya, Tortuga, and Margarita areas are secondary sources of local influence. These insights shed light on the origin of present-day terrigenous sediments of the Cariaco Basin and help to propose alternative explanations for the temporal variability of clay mineralogy observed in previously published studies.

  5. Habitable paleoenvironments preserved in pedogenically altered clay-rich sediments at Mawrth Vallis, Mars

    NASA Astrophysics Data System (ADS)

    Horgan, B.; Kahmann-Robinson, J. A.; Bishop, J. L.; Christensen, P.

    2013-09-01

    Using detailed analysis of CRISM observations, we show that clay and sulfate minerals near Mawrth Vallis are consistent with pedogenic alteration of volcaniclastic sediments. Based on terrestrial analogs, the mineral assemblage is consistent with surface weathering under a sustained semi-arid climate locally modified by acid-sulphate reactions due to oxidation of reduced Fe/S phases produced in water logged surface environments.

  6. Tool for Taking Clay Impressions

    NASA Technical Reports Server (NTRS)

    Duncan, R. S.

    1984-01-01

    Clay impression of small parts taken with tool consisting of hollow tube closed at one end. Slots at other end admit part short distance into tube. Impression used to make silicone rubber mold for examination.

  7. GRASSLAND SONGBIRD ABUNDANCE ALONG ROADS AND TRAILS IN SOUTHERN SASKATCHEWAN

    Microsoft Academic Search

    GLENN C. SUTTER; STEPHEN K. DAVIS; DAVID C. DUNCAN

    We conducted roadside and trail-side point count surveys to determine whether grassland bird abundance differs along ditched and non-ditched sampling points in south- western Saskatchewan. Savannah and Vesper Sparrows were more abundant along roads, while Baird's Sparrows, Chestnut-collared Longspurs, and Sprague's Pipits were more abun- dant along trails. Clay-colored Sparrows, Horned Larks, and Western Meadowlarks were de- tected equally along

  8. Jamaican red clay tobacco pipes 

    E-print Network

    Heidtke, Kenan Paul

    1992-01-01

    -made earthenware tobacco pipes has only been undertaken in the last few years. These red clay pipes occur at several colonial sites in North America, the Caribbean, and South America. This thesis will be a detailed study of the red clay pipes found in Jamaica... used on the pipes, and to offer possible explanations for the markings and stylistic attributes of the pipes. Locally made earthenware pipes from other colonial sites in the New World will also be examined to identify possible parallels...

  9. Application of solution-mineral equilibrium chemistry to solution mining of uranium ores

    Microsoft Academic Search

    A. C. Riese; C. J. Propp

    1980-01-01

    Modern methods of uranium solution mining are typically accompanied by gains and losses of mass through reagent consumption by rock-forming minerals, with subsequent formation of clay minerals, gypsum, carbonates, and iron oxyhydroxides. A systematic approach to alleviate such problems involves the application of leach solutions that are in equilibrium with the host-rock minerals but in disequilibrium with the ore-forming minerals.

  10. The Mineral Scoring Technique and Evaluation of Indigenous Browse Species as Natural Mineral Phytocentres for Goats in African Rangelands

    Microsoft Academic Search

    J. D. Kabasa; J. Opuda-Asibo; G. Thinggaard; U. ter Meulen

    2004-01-01

    The utilization and evaluation of indigenous browse species as natural mineral phytocentres for goats was examined by the combined use of mineral concentrations, mineral scores, browse accessibility and abundance in the Ankole rangeland, Uganda. The species Grewia bicolor and Carissa edulis with Acacia albida and Acacia abyssinica with Acacia and lowest (5.3%) in Dichrostachys. Browse accessibility was Acacia hockii was

  11. To what extent clay mineralogy affects soil aggregation? Consequences for soil organic matter stabilization

    NASA Astrophysics Data System (ADS)

    Fernandez-Ugalde, O.; Barré, P.; Hubert, F.; Virto, I.; Chenu, C.; Ferrage, E.; Caner, L.

    2012-12-01

    Aggregation is a key process for soil functioning as it influences C storage, vulnerability to erosion and water holding capacity. While the influence of soil organic C on aggregation has been documented, much less is known about the role of soil mineralogy. Soils usually contain a mixture of clay minerals with contrasted surface properties, which should result on different abilities of clay minerals to aggregation. We took advantage of the intrinsic mineral heterogeneity of a temperate Luvisol to compare the role of clay minerals (illite, smectite, kaolinite, and mixed-layer illite-smectite) in aggregation. In a first step, grassland and tilled soil samples were fractionated in water in aggregate-size classes according to the hierarchical model of aggregation (Tisdall and Oades, 1982). Clay mineralogy and organic C in the aggregate-size classes were analyzed. The results showed that interstratified minerals containing swelling phases accumulated in aggregated fractions (>2 ?m) compared to free clay fractions (<2 ?m) in the two land-uses. The accumulation increased from large macro-aggregates (>500 ?m) to micro-aggregates (50-250 ?m). C concentration and C/N ratio followed the opposite trend. These results constitute a clay mineral-based evidence for the hierarchical model of aggregation, which postulates an increasing importance of the reactivity of clay minerals in the formation of micro-aggregates compared to larger aggregates. In the latter aggregates, formation relies on the physical enmeshment of particles by fungal hyphae, and root and microbial exudates. In a second step, micro-aggregates from the tilled soil samples were submitted to increasingly disaggregating treatments by sonication to evaluate the link between their water stability and clay mineralogy. Micro-aggregates with increasing stability showed an increase of interstratified minerals containing swelling phases and C concentration for low intensities of disaggregation (from 0 to 5 J mL-1). This suggests that swelling phases promote their stability. Swelling phases and organic C decreased for greater intensities of disaggregation. These results and the SEM images taken at different disaggregation intensities indicate that when increasing disaggregation intensity above 5 J mL-1, the recovered material consists on sand particles covered by physical coatings of illite and kaolinite. Our results show that different clay minerals have different contribution to soil aggregation. Swelling phases are especially important for water-stable aggregates formation, whereas illite and kaolinite can either contribute to aggregation or been coated to sand grains in "mineral aggregates", without porosity and organic C protection capability. In conclusion, soils with large proportion of swelling clay minerals have greater potential for carbon storage by occlusion in aggregates and greater resistance to erosion. Tisdall JM, Oades JM (1982) Organic matter and water-stable aggregates in soils. J Soil Sci 62: 141-163.

  12. Provenance of Late Cretaceous to Paleocene submarine fan sandstones in the Norwegian Sea: Integration of heavy mineral, mineral chemical and zircon age data

    Microsoft Academic Search

    A. C. Morton; A. G. Whitham; C. M. Fanning

    2005-01-01

    This paper describes a strategy for effective discrimination and provenance evaluation of sandstones transported by different sediment dispersal systems using an integrated programme of heavy mineral analysis, mineral chemistry and zircon age dating. Sandstones derived from different source regions are initially discriminated using provenance sensitive heavy mineral parameters (ratios of abundances of stable, hydraulically equivalent minerals). Differences between the heavy

  13. Clay and non-clay minerals in the pharmaceutical industry Part I. Excipients and medical applications

    E-print Network

    Ahmad, Sajjad

    ) immobilization of limbs and fractures or dental and craniofacial surgical procedures in traumatology, d) bone, and traumatological applications, and are used in spas and aesthetic centers for therapeutic proposes (Fig. 1

  14. Competitive sorption of pyrene and pyridine to natural clay minerals and reference clay standards 

    E-print Network

    Lee, Lai Man

    2001-01-01

    competing solute, pyridine. Past studies have shown that pyridine can be directly coordinated to exchangeable cations; therefore, it can theoretically compete with pyrene for specific sites. Equilibrium sorption isotherms were modeled with the Freundlich...

  15. Molecular Scale Determinants of Organic Contaminant and Pesticide Sorption by Clays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Clay minerals and soil organic matter (SOM) are generally considered to be the most important soil components in the sorption of aqueous phase organic contaminants. During the past 25 years, much emphasis has been placed on the dominant role of SOM in sorption. However, there is increasing evidence...

  16. In situ inorganic foams prepared from various clays at low temperature

    Microsoft Academic Search

    E. Prud'homme; P. Michaud; E. Joussein; C. Peyratout; A. Smith; S. Rossignol

    2011-01-01

    Geopolymers are amorphous three-dimensional aluminosilicate binder materials that may be synthesized at room or slightly higher temperature by alkaline activation of aluminosilicates obtained from industrial wastes, calcined clays, natural minerals or mixtures of two or more of these materials. Among the different families of geopolymers, those based on potassium show modified thermal and mechanical properties due to the larger size

  17. BEYOND SKOGHOLM COTONEASTER: PERFORMANCE OF HYDRANGEA, AZALEA, JUNIPER AND SPIREA IN A CLAY AMENDED SUBSTRATE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Georgiana industrial mineral aggregates (clay) can be used to amend pine-bark based soilless substrate in the southeastern US to reduce phosphorus (P) leaching, provide nutrients, and increase substrate water buffering capacity. However, the effect on plant growth is species specific. Hydrangea, a...

  18. Ultrafiltration by a compacted clay membrane-II. Sodium ion exclusion at various ionic strengths

    USGS Publications Warehouse

    Hanshaw, B.B.; Coplen, T.B.

    1973-01-01

    Several recent laboratory studies and field investigations have indicated that shales and compacted clay minerals behave as semipermeable membranes. One of the properties of semipermeable membranes is to retard or prevent the passage of charged ionic species through the membrane pores while allowing relatively free movement of uncharged species. This phenomenon is termed salt filtering, reverse osmosis, or ultrafiltration. This paper shows how one can proceed from the ion exchange capacity of clay minerals and, by means of Donnan membrane equilibrium concept and the Teorell-Meyer-Siever theory, develop a theory to explain why and to what extent ultrafiltration occurs when solutions of known concentration are forced to flow through a clay membrane. Reasonable agreement between theory and laboratory results were found. The concentration of the ultrafiltrate was always greater than predicted because of uncertainty in values of some parameters in the equations. Ultrafiltration phenomena may be responsible for the formation of some subsurface brines and mineral deposits. The effect should also be taken into consideration in any proposal for subsurface waste emplacement in an environment containing large quantities of clay minerals. ?? 1973.

  19. Natural Ferrihydrite as an Agent for Reducing Turbidity Caused by Suspended Clays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The turbidity of water can be reduced by the addition of positively charged compounds which coagulate negatively charged clay particles in suspension causing them to flocculate. This research was conducted to determine the effectiveness of the Fe oxide mineral ferrihydrite as a flocculating agent fo...

  20. FINDING THE BALANCE: CALCINED CLAY RATE EFFECTS IN PINE BARK SUBSTRATES.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The addition of 710 um to 300 um (24/28 mesh) calcined (LVM) Georgia palygorksite-bentonite mineral at ~ 11% (by vol.) to pine bark increased "Stogholm" contoneaster dry weight 39% when compared to a pine bark substrate. When clay was used to amend pine bark at rates greater that 12% (by vol.) plan...

  1. Sequestration of volatiles in the martian crust through hydrated minerals

    NASA Astrophysics Data System (ADS)

    Mustard, J. F.; Ehlmann, B. L.; Poulet, F.; Fraeman, A. A.; Carter, J.

    2011-12-01

    The magnitude and history of volatile reservoirs is a key question in understanding Mars' evolution. The volumes of reservoirs for water through time have been estimated on the basis of morphology (e.g. Carr 1996) and modeling while the volume of active identifiable modern reservoirs such as the polar caps, the near-surface cryosphere, and the atmosphere are reasonably well known. One reservoir that has been hypothesized but not examined is the crust where water would be in the form of hydrous minerals. The OMEGA and CRISM experiments on Mars Express and Mars Reconnaissance Orbiter respectively, have shown that phyllosilicate minerals are commonly observed in the Noachian crust of Mars. Modeling has shown that depending on the location the abundance of clays and phyllosilicates can exceed 50% but more typically is less or absent, particularly in the Hesperian and younger terrains (Poulet 2007). Phyllosilicate-bearing outcrops have been observed in the deepest wall exposures of Valles Marineris (8 km below the rim) and in the central peaks of impact craters as large of 100 km. Modeling suggests that the porosity of the crust in maintained to approximate 8-10 km depth permitting the circulation of water to this depth and formation of phyllosilicate and other hydrated minerals. Based on these and other observations it is evident that at least the top 10 km of the crust can be considered to contain hydrated silicate minerals. These observations also show that phyllosilicates are globally present in Noachian crust. We use altered oceanic crust as an analog for the amount of alteration on Mars. Analyses show that the average volume fraction of hydrous phases in the lower oceanic crust is 10%. Simple calculations show this results in a water content of between 1 - 3%. If the upper 10 km of the martian crust is altered to this extent then a global equivalent thickness (GET) of water of 0.3 to 0.9 km is stored in the crust due to alteration minerals. This is comparable to the GET derived from geologic evidence (Carr, 1996). We will expand on these calculations and their implications for the meeting.

  2. The Fluid Memory of Clays in Faults and Folds

    NASA Astrophysics Data System (ADS)

    van der Pluijm, B.; Fitz-Diaz, E.; Haines, S. H.

    2013-12-01

    Constraining fluid sources is key to understanding crustal-scale fluid circulation, rock mechanics, mineral reactions and the origin of economic deposits. The role of meteoric fluids in exhumed fault rocks has been proposed in a few recent studies, notably in mylonites in low-angle normal fault (LANF) systems. However, the extent of meteoric influx and fluid pathways, and a mechanism for infiltration of surface waters up to 10+km depth remains mostly unknown. The occurrence of clay neomineralization in fault rocks and folds has the potential to resolve this question, as clay (trans)formation preserves host fluid information in its isotopic signatures, particularly H. New stable isotope studies of clays in normal faults and folds in the SW US and Mexico show major meteoric input, based on which we propose a mechanism for downward fluid infiltration and upper-crustal circulation. We obtained paired ?18O and ?2H (‰ wrt SMOW) isotopic measurements from neo-formed clays in fault gouge that formed above major LANF detachments in the SW US, which show that clays in brittle fault rocks formed from exchange with pristine to only weakly evolved meteoric fluids. Illite ?18O measurements range from -2.0‰ to +11.5‰, while illite ?2H measurements range from -142‰ to -107‰. Smectite ?18O values are +3.6‰ to 17.9‰, while smectite ?2H measurements are -147‰ to -95‰. The isotopic signature of clays at multiple depths in LANFs indicates that crustal-scale normal fault systems are highly permeable over geologic time scales, and that they are dominated by downward fluid flow of surface waters, instead of buoyancy-driven flow from deeper levels. Clay grain size fractions from folded rocks of the Mexican fold-thrust belt containing chlorite and smectite show very low values in ?2H (-75.9 to -53.9‰), while samples containing illite and kaolinite or pure illite show slightly higher ?2H values (-33.1 to -50.1‰). In these samples the discriminating potential of ?18O values of clay is generally masked by the presence of calcite. The ?2H values in these folds indicate that active fluids infiltrated from the surface during folding, partially diluted by formation fluid. Based on major input of meteoric fluids in these extensional and contractional settings, we propose a dynamic scenario for surface fluid infiltration that involves whole upper crust fluid circulation along interconnected, transient networks of brittle faults and fractures that are activated during regional deformation. Drawdown of meteoric fluids is facilitated by the opening and closing of spaces in these evolving fracture networks.

  3. An Impact Origin for Surface Minerals on Ceres

    NASA Astrophysics Data System (ADS)

    Zolotov, M. Y.

    2013-12-01

    The dwarf planet Ceres is the largest body in the main asteroid belt with a hydrated dark rocky surface and an uncertain internal structure [1,2]. Spectra of Ceres in the near- and mid-infrared ranges show that surface materials may not contain abundant serpentine, saponite, sulfates, olivine, pyroxenes, and organic matter [2,3], which are common in carbonaceous chondrites. However, brucite, Mg carbonates, cronstedtite, and magnetite could be abundant and indicate aqueous processes [2,3]. The formation of abundant brucite, carbonates, and cronstedtite requires open-system low-temperature conditions characterized by elevated water/rock ratios and low fugacities of hydrogen and carbon dioxide. The observed mineralogy is more consistent with a near-surface origin than with a formation within Ceres or on planetesimals. The instability of aqueous solutions at the surface of Ceres implies mineral deposition during transient events of fluidal activity. But a warming of near-surface rocks by thermal processes in the interior requires dehydration of rocks, which is not consistent with the low density of Ceres. The lack of low-solubility sulfates in surface materials does not indicate percolation of interior fluids. Carbonate-bearing fluids may not percolate to the cold surface, especially if Ceres had undergone water-rock differentiation [1,4]. The lack of serpentine in surface materials does not indicate a formation of brucite through aqueous alteration of olivine-rich rocks. Though, the observed minerals could form in impact collisions of ice-rich targets and/or impactors. OH-bearing phases may condense from water-rich impact plumes [5]. Brucite and Mg carbonates could form through hydrolysis and carbonation of condensed MgO formed through evaporation of silicates. Apparently abundant carbonates may indicate an ample oxidation of organics. Ferric iron in magnetite and cronstedtite agrees with water-rich and oxidizing impact settings [5]. Turbulent and disequilibrium environments in impact plumes and surges could have led to deposition of minerals which typically do not form together (e.g., brucite and cronstedtite). Aqueous minerals could have formed in impact clouds, crater outflows, transient ice-covered crater lakes, and related hydrothermal systems. The observed clay-sized and spatially homogeneous surface materials [2] could be gravitationally sorted deposits of impact clouds and surges. The surface materials could have formed through impacts on an icy shell of a differentiated Ceres during the Late Heavy Bombardment (LHB) in the inner solar system, which affected may other asteroids [6]. However, mineral-forming processes during collisions of an undifferentiated and hydrated Ceres with water-rich bodies during LHB remain a possibility. A detection of fluidized crater outflows together with topography and composition of surface materials with Dawn will test this hypothesis. Refs: [1] McCord, T.B. et al. (2011) Space Sci. Rev. 163, 63-76. [2] Rivkin, A.S. et al. (2011) Space Sci. Rev. 101, 1-22. [3] Milliken, R.E., and Rivkin, A.S. (2009) Nature Geoscience 2, 258-261. [4] Castillo-Rogez, J.C., and McCord, T.B. (2010) Icarus 205, 443-459. [5] Gerasimov, M.V. et al. (2002) Deep-Sea Res. II 49, 995-1009. [6] Marchi, S. et al. (2013) Nature Geoscience, 6, 303-307.

  4. Rubber–pristine clay nanocomposites prepared by co-coagulating rubber latex and clay aqueous suspension

    Microsoft Academic Search

    You-Ping Wu; Yi-Qing Wang; Hui-Feng Zhang; Yi-Zhong Wang; Ding-Sheng Yu; Li-Qun Zhang; Jun Yang

    2005-01-01

    The structure of several rubber–clay nanocomposites, including styrene butadiene rubber (SBR)–clay, natural rubber (NR)–clay, nitrile butadiene rubber (NBR)–clay, carboxylated acrylonitrile butadiene rubber (CNBR)–clay nanocomposites, prepared by directly co-coagulating the rubber latex and clay aqueous suspension, were investigated. X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM) micrographs showed that these nanocomposites possessed a unique structure, in which the rubber molecules

  5. The mineral scoring technique and evaluation of indigenous browse species as natural mineral phytocentres for goats in African rangelands.

    PubMed

    Kabasa, J D; Opuda-Asibo, J; Thinggaard, G; ter Meulen, U

    2004-05-01

    The utilization and evaluation of indigenous browse species as natural mineral phytocentres for goats was examined by the combined use of mineral concentrations, mineral scores, browse accessibility and abundance in the Ankole rangeland, Uganda. The species Grewia bicolor and Carissa edulis with > 140% mineral scores and > 70% accessibility were the most valuable mineral phytocentres and were the victims of overgrazing. Acacia albida and Acacia abyssinica with > 130% mineral scores but < 30% browse accessibility were valuable for the cut-and-carry feeding system. Species mineral scores at average and maximum dietary recommendations were < 60%, highlighting the mineral insufficiency of range browse for high-performance goats. Mineral supply potential was highest (35.0%) in the genus Acacia and lowest (5.3%) in Dichrostachsys. Browse accessibility was < 35%, in 69.2% of species. Acacia hockii was the most abundant species (24.5%) but had the lowest mineral score (17.7%). Browse species (90-100%) were deficient in Fe, Mn, Cu and Zn. The combined use of mineral concentrations and mineral scoring technique was superior to the use of mineral concentrations alone in defining mineral adequacy, deficiency and supply potential, making the mineral scoring technique a valuable tool in browse management. PMID:15241970

  6. Carbon and nitrogen mineralization are decoupled in organo-mineral fractions

    NASA Astrophysics Data System (ADS)

    Bimüller, Carolin; Mueller, Carsten W.; von Lützow, Margit; Kreyling, Olivia; Kölbl, Angelika; Haug, Stephan; Schloter, Michael; Kögel-Knabner, Ingrid

    2015-04-01

    To improve our comprehension how carbon and nitrogen mineralization are linked in soils, we used a controlled laboratory mineralization approach and compared carbon and nitrogen dynamics in the bulk soil and in soil fractions. Topsoil of a Rendzic Leptosol from a beech forest site near Tuttlingen, Germany, was fractionated into three particle size classes: sand (2000 to 20 µm), silt (20 to 2 µm), and clay (< 2 µm). Bulk soil and particle size fractions were incubated for 40 weeks allowing periodic destructive sampling. We monitored carbon and nitrogen mineralization dynamics, and assessed carbon respiration as well as nitrogen mineralization and microbial biomass carbon and nitrogen contents. Soil organic matter in the incubated fractions was considered by a subsequent density fractionation. The chemical composition of selected samples was qualitatively evaluated by 13C-NMR spectroscopy. When summing up the mineralization rates of the single fractions, the values for respired carbon equaled the bulk soil, whereas the mathematical recombination of mineral nitrogen in all fractions was significantly less than in bulk soil. Hence, carbon mineralization was not affected by the damage of the aggregated soil structure via fractionation, whereas nitrogen mineralization was reduced. Fractionation increased the surface area providing accessory mineral surfaces, which allowed new binding of especially nitrogen-rich compounds, besides ammonium fixation via cation exchange. Density fractionation revealed that organic matter in the sand fraction contained mainly particulate organic matter present as light material comprising partly decomposed plant remnants. The organic matter in the clay fraction was mostly adsorbed on mineral surfaces. Organic matter in the sand and in the clay fraction was dominated by O/N-alkyl C indicating low recalcitrance, but the C/N ratio of organic matter narrowed with decreasing particle size. These results also imply that the C/N ratio as well as the alkyl C to O/N-alkyl C ratio are not suitable to draw conclusions regarding biological decomposability of plant residues when characterizing soil fractions where organic matter is mainly stabilized by spatial inaccessibility and by organo-mineral interactions. The specific interactions of both carbon and nitrogen containing components with the mineral matrix strongly modulate the mineralization dynamics, leading to a decoupling of these processes.

  7. CO2/clay interactions and the significance for geological storage of carbon dioxide

    NASA Astrophysics Data System (ADS)

    Busch, Andreas; Wentinck, Rick; Bertier, Pieter

    2015-04-01

    For the characterization of CO2 storage reservoirs a number of critical parameters need to be assessed, like storage capacity or injection rate, where a straight-forward work flow based on existing experience in the oil and gas industry is available. Added complexity is in the identification of (potential) leakage pathways along wellbores, faults/fractures or even capillary seal networks. The critical aspects are mechanisms and rates of potential leakage. Over the past few years an improved understanding of the interaction of CO2 with clay minerals was generated, with a major focus on swelling clays, such as montmorillonite. Especially in relatively young and / or low maturity sedimentary basins, smectite contents of the seal lithologies can be high (e.g. North Sea). It was found that for CO2 storage and storage containment non-negligible physical effects result from clays in contact with CO2 and water under pressure, temperature and stress conditions representative for geological reservoirs. It was shown that all clay minerals are able to adsorb significant amounts of CO2, while only smectite swells in the presence of CO2, thereby creating a swelling force that is potentially large and may affect local stress fields. Several cases where this interaction might become important are discussed in this contribution: (1) clay swelling between wellbore cement and host rock, (2) CO2 adsorption of clays in the storage reservoir, (3) clay swelling and the impact on fractures and faults, potentially acting as pathways, for fluid leakage and (4) shrinkage of swelling clays due to dehydration by CO2 and the possible creation of dehydration cracks. This contribution aims at summarizing these effects, increasing awareness and discussing its significance for the geological storage of CO2.

  8. Iodide Sorption to Clays and the Relationship to the Surface Charge Environment

    NASA Astrophysics Data System (ADS)

    Miller, A. W.; Wang, Y.

    2011-12-01

    In performance assessments of nuclear waste repositories, iodine-129 is often the major contributor to dose at time scales ?10,000 years. The breakthrough behavior of iodine is determined by the monovalent, anionic nature and the assumed lack of surface reactivity of the iodide ion. This assumption is corroborated by batch sorption data where iodide sorption to clays is typically very small, and only measurable under specific conditions. This result is consistent with charge repulsion arguments due to the fixed negative charge of clays repelling the anionic iodide. However, in compacted column diffusion experiments, iodide is routinely retarded relative to tritium, and is described with Kd values from ?0.001-2.9ml/g. While small, these values can dramatically change the dose profile in performance assessment calculations. We hypothesize that contributions from the basal plane and edge charge of individual clay particles as well as the physical morphology of the clay particles are contributing to the conflicting behavior. In a series of experiments involving a wide range of clay minerals from the clay bank repository, both surface charge and iodide sorption were examined using surface titrations and batch sorption experiments. The clay minerals studied include: kaolinite, ripidolite, illite, montmorillonite, palygorskite, sepiolite, and an illite/smectite mixed layer clay. Each of these clays was characterized using XRD, and surface titrations in 0.01, 0.1, and 0.5 M NaCl electrolyte. The titrations spanned the pH range from 2.5-10.5 and were automated using an autotitrator. For reference, similar titrations were performed on pure forms of an Al-O powder. The titration curves were interpreted using an inversion method to attain the pKa distribution for each clay and metal oxide at each ionic strength. The pKa distribution for the Al-O shows two distinct peaks at 4.8 and 7.5, which are invariant with ionic strength. The pKa distribution of clays was highly variable between the different minerals and, more importantly, the distribution for an individual clay mineral changed as a function of ionic strength. This behavior implies a more complicated vision of clay surface chemistry than traditional surface complexation descriptions allow. Iodide sorption experiments were completed at relatively high solid:solution ratios to exacerbate sorption properties. The results show a range of sorption behaviors across the clay minerals based on solid:solution ratio, pH, and ionic strength. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  9. Physical Alteration of Martian Dust Grains, Its Influence on Detection of Clays and Identification of Aqueous Processes on Mars

    NASA Technical Reports Server (NTRS)

    Bishop, Janice L.; Drief, Ahmed; Dyar, Darby

    2003-01-01

    Clays, if present on Mars, have been illusive. Determining whether or not clay minerals and other aqueous alteration species are present on Mars provides key information about the extent and duration of aqueous processes on Mars. The purpose of this study is to characterize in detail changes in the mineral grains resulting from grinding and to assess the influence of physical processes on clay minerals on the surface of Mars. Physical alteration through grinding was shown to greatly affect the structure and a number of properties of antigorite and kaolinite. This project builds on an initial study and includes a combination of SEM, HRTEM, reflectance and M ssbauer spectroscopies. Grain size was found to decrease, as expected, with grinding. In addition, nanophase carbonate, Si-OH and iron oxide species were formed.

  10. Reflectance Spectroscopy of Palagonite and Iron-Rich Montmorillonite Clay Mixtures: Implications for the Surface Composition of Mars

    NASA Technical Reports Server (NTRS)

    Orenberg, James; Handy, Jonathan

    1992-01-01

    Mixtures of a Hawaiian palagonite and an iron-rich, montmorillonite clay (15.8 +/- 0.4 wt% Fe as Fe2O3) were evaluated as Mars surface spectral analogs from their diffuse reflectance spectra. The presence of the 2.2 microns absorption band in the reflectance spectrum of clays and its absence in the Mars spectrum have been interpreted as indicating that highly crystalline aluminous hydroxylated clays cannot be a major mineral component of the soil on Mars. The palagonite sample used in this study does not show this absorption feature in its spectrum. In mixtures of palagonite and iron-rich montmorillonite, the 2.2 microns Al-OH clay lattice band is not seen below 15 wt% montmorillonite. This suggests the possibility that iron-rich montmorillonite clay may be present in the soil of Mars at up to 15 wt% in combination with palagonite, and remain undetected in remotely sensed spectra of Mars.

  11. Interaction of polymer with clays.

    SciTech Connect

    Auvray, L.; Lal, J.

    1999-07-02

    Normally synthetic well defined monodisperse discotic laponite clays are known to form a gel phase at mass concentrations as low as a few percent in distilled water. Hydrosoluble polymer polyethylene oxide was added to this intriguing clay system, it was observed that it either prevents gelation or slows it down extremely depending on the polymer weight, concentration or the laponite concentration. Small Angle Neutron scattering (SANS) was used to study these systems because only by isotopic labelling can the structure of the adsorbed polymer layers be determined. The contrast variation technique is specifically used to determine separately the different partial structure factors of the clay and polymer. In this way the signal of the adsorbed chains is separated from the signal of the free chains.

  12. Boron Enrichment in Martian Clay

    PubMed Central

    Nagashima, Kazuhide; Freeland, Stephen J.

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration. PMID:23762242

  13. Characterization of structures of the Nankai Trough accretionary prism from integrated analyses of LWD log response, resistivity images and clay mineralogy of cuttings: Expedition 338 Site C0002

    NASA Astrophysics Data System (ADS)

    Jurado, Maria Jose; Schleicher, Anja

    2014-05-01

    The objective of our research is a detailed characterization of structures on the basis of LWD oriented images and logs,and clay mineralogy of cuttings from Hole C0002F of the Nankai Trough accretionary prism. Our results show an integrated interpretation of structures derived from borehole images, petrophysical characterization on LWD logs and cuttings mineralogy. The geometry of the structure intersected at Hole C0002F has been characterized by the interpretation of oriented borehole resistivity images acquired during IODP Expedition 338. The characterization of structural features, faults and fracture zones is based on a detailed post-cruise interpretation of bedding and fractures on borehole images and also on the analysis of Logging While Drilling (LWD) log response (gamma radioactivity, resistivity and sonic logs). The interpretation and complete characterization of structures (fractures, fracture zones, fault zones, folds) was achieved after detailed shorebased reprocessing of resistivity images, which allowed to enhance bedding and fracture's imaging for geometry and orientation interpretation. In order to characterize distinctive petrophysical properties based on LWD log response, it could be compared with compositional changes derived from cuttings analyses. Cuttings analyses were used to calibrate and to characterize log response and to verify interpretations in terms of changes in composition and texture at fractures and fault zones defined on borehole images. Cuttings were taken routinely every 5 m during Expedition 338, indicating a clay-dominated lithology of silty claystone with interbeds of weakly consolidated, fine sandstones. The main mineralogical components are clay minerals, quartz, feldspar and calcite. Selected cuttings were taken from areas of interest as defined on LWD logs and images. The clay mineralogy was investigated on the <2 micron clay-size fraction, with special focus on smectite and illite minerals. Based on X-ray diffraction analysis measured at room temperature and a relative humidity of ~30%, we compared the shape and size of illite and smectite, as well as their water content and their polytypes. The comparison of cuttings mineralogy with logging while drilling (LWD) data allowed us to characterize structural, petrophysical and mineralogical properties at fracture and fault zones. We also analyzed the relationship between deformation structures and compositional and mineralogical changes. We established a correlation between observed results on clay mineralogy and log responses in relation with the structures and trends characterized on logging data. In general, the log data provide a good correlation with the actual mineralogy and the relative abundance of clay. In particular we analyzed trends characterized by smectite water layers as indication of compaction. These trends were correlated with log response (on sonic velocity) within Unit IV. Our results show the integration of logging data and cutting sample analyses as a valuable tool for characterization of petrophysical and mineralogical changes of the structures of the Nankai accretionary prism.

  14. CLAY AND SHALE--1998 R1 CLAY AND SHALE

    E-print Network

    processors and manufacturers of lightweight aggregate, brick, tile, and whiteware are covered under the MACT be developed by September 2000 (American Ceramic Society Bulletin, 1998). Clay mining has an environmental trees or grasses to prevent or minimize erosion. For processing, the impoundment of slimes and dust

  15. Prions, Radionuclides and Clays: Impact of clay interlayer

    Microsoft Academic Search

    L. Charlet; C. Hureau; O. Sobolev; G. Cuello; Y. Chapron

    2007-01-01

    The physical and chemical processes that are the basis of contaminant retardation in clay rich medium, such as soil or nuclear waste repository, have been studied at the molecular level by a combination of molecular dynamics (MD), electron paramagnetic spectroscopy (EPR) and neutron diffraction with isotopic substitution (NDIS). The speciation of contaminants such as Sm, a radionuclide analogue, and Cu,

  16. Beneficiation of heavy minerals from bituminous sands residues by dry screening

    Microsoft Academic Search

    A. Maskwa; L. Trevoy

    1980-01-01

    The titanium and zirconium-based minerals, present in the first stage centrifuge tailings from the hot water process for extraction of bitumen from bituminous sands, may be concentrated by a dry screening process. The tailings are burned off to provide a dry, essentially carbon-free, mineral mixture. By screening the mixture into three streams of different particle size range, silica and clays

  17. Geomycology: biogeochemical transformations of rocks, minerals, metals and radionuclides by fungi, bioweathering and bioremediation

    Microsoft Academic Search

    Geoffrey M. Gadd

    2007-01-01

    The study of the role that fungi have played and are playing in fundamental geological processes can be termed ‘geomycology’ and this article seeks to emphasize the fundamental importance of fungi in several key areas. These include organic and inorganic transformations and element cycling, rock and mineral transformations, bioweathering, mycogenic mineral formation, fungal–clay interactions, metal–fungal interactions, and the significance of

  18. Effects of mixing energy on the sedimentation of vegetable oil spills by clay.

    PubMed

    Wrenn, B A; Downer, R J; Venosa, A D

    2010-11-01

    The effects of clay dose and mixing energy on the efficiency of vegetable oil sedimentation by clay are investigated. The sedimentation efficiency increased with increasing clay dose to a maximum of about 80% of added oil. The maximum sedimentation efficiency was achieved at a lower clay dose, and the sedimentation efficiency was greater for a given clay dose when the oil was present as a thick oil film rather than as a thinner film. Sedimentation efficiency was relatively constant for mixing energies less than about 0.01 m2 s(-3) (0.01 W kg(-1)) but decreased dramatically at higher energy dissipation rates. Mixing energy may not be an important factor in determining the effectiveness of this response alternative because energy dissipation rates in natural surface water bodies under most typical conditions are less than 0.01 m2 s(-3). The effects of oil film thickness and mixing energy on the efficiency of vegetable oil sedimentation suggests that vegetable oil-mineral aggregates (VOMA) form through a different mechanism to that of petroleum oil-mineral aggregates (OMA). One consequence of the different formation mechanisms is that VOMA are much larger than petroleum OMA. PMID:21121454

  19. Mathematical models for degradation of clay constructions

    E-print Network

    Tradacete, Pedro

    Seminario Mathematical models for degradation of clay constructions: application to Por fortress walls, are made of clay. The place is difficult of access and sparsely populated; this caused quite a good conservation of the clay constructions of the site in general and their decay is due

  20. Hands-on Virtual Clay Adeline Pihuit

    E-print Network

    Paris-Sud XI, Université de

    Hands-on Virtual Clay Adeline Pihuit University of Grenoble and INRIA Paul G. Kry McGill University virtual hand that is modeling soft virtual clay. During interaction, the user is provided both passive of sculpting virtual clay as naturally as he would do it with his hands. Generally, he must deal