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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

Green Clay Minerals  

NASA Astrophysics Data System (ADS)

Color is a problem for scientific study. One aspect is the vocabulary one used to describe color. Mint green, bottle green, and Kelly green are nice names but not of great utility in that people's physical perception of color is not always the same. In some industries, such as colored fabric manufacture, current use is to send a set of standard colors which are matched by the producer. This is similar to the use of the Munsell color charts in geology. None of these processes makes use of physical optical spectral studies. The reason is that they are difficult to obtain and interpret. For a geologist, color is very important but we rarely have the possibility to standardize the method of our color perception. One reason is that color is both a reflective and transmission phenomenon. The thickness of the sample is critical to any transmission characteristics. Hence, a field color determination is different from one made by using a petrographic microscope. Green glauconite in a hand specimen is not the same color in 30 ?m thick thin section seen with a microscope using transmitted light.A second problem is that color in a spectral identification is the result of several absorption emissions,with overlapping signal, forming a complicated spectrum. Interpretation depends very greatly on the spectrum of the light source and the conditions of transmission-reflection of the sample. As a result, for this text, we will not attempt to analyze the physical aspect of green in green clays. In the discussion which follows, reference is made concerning color, to thin section microscopic perception.Very briefly, green clay minerals are green, because they contain iron. This is perhaps not a great revelation to mineralogists, but it is the key to understanding the origin and stability of green clay minerals. In fact, iron can color minerals either red or green or in various shades of orange and brown. The color most likely depends upon the relative abundance of the iron ion valence in the silicate (clay mineral in our case) structure, the specific bonding of these ions, and other factors. In fact, the reasons for coloration are not known completely, but it is certain that a combination of Fe2+ and Fe3+ ions is necessary to give a nice green color to clays. In the green clay minerals discussed here, the colors vary greatly as seen under the optical microscope (not always the same as the one seen in hand specimen). Yellow to blue-green hues can be found. However, for the moment, no clear relation between iron content, iron valence ratio, or other factors such as minor transition element concentrations can be found to explain the greenness of green clay minerals. The fact that a clay is green just indicates a combination of the two oxidation states of iron. The color, however, indicates the key to the formation in nature of green clay minerals.Green clay minerals are in general the product of "mixed valence" conditions of formation, most often in a situation where some iron is reduced from Fe3+ and enters into a silicate mineral structure. In general, iron would rather be an oxide when it is in the trivalent state. The moment iron is reduced to a divalent state under surface or near-surface conditions, it looks for a silicate, sulfide, or carbonate to hide in. The reverse is also true, of course. When a silicate is oxidized, Fe2+ becoming Fe3+, the iron begins to group together in oxide clumps and eventually exits the silicate structure. This is seen in thin section in altered rocks (weathering or hydrothermal action). The production of trivalent, oxidized iron usually results in a brownish or orange mineral.If the geology of the formation of green silicate minerals is relatively well defined, especially at near surface or surface conditions, the question remains how much of the iron is in a reduced oxidation state and how? In the case of reduction of iron in surface environments: if most of the iron goes to Fe2+, one mineral is formed; if only part of it is reduced, another is formed. This is the fundamental geochemical aspect of

Velde, B.

2003-12-01

3

Clay Mineral: Radiological Characterization  

SciTech Connect

Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and {sup 40}K in these clay minerals.The objective of this work is to determine the concentrations of {sup 238}U, {sup 232}Th, {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 40}K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay.Measurement for the determination of {sup 238}U and {sup 232}Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 40}K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906{+-}340 Bq kg{sup -1} for {sup 40}K, 40{+-}9 Bq kg{sup -1} for {sup 226}Ra, 75{+-}9 Bq kg{sup -1} for {sup 228}Ra, 197{+-}38 Bq kg{sup -1} for {sup 210}Pb, 51{+-}26 Bq kg{sup -1} for {sup 238}U and 55{+-}24 Bq kg{sup -1} for {sup 232}Th, considering both kinds of clay.

Cotomacio, J. G. [Centro Universitario Nove de Julho, R: Diamantina, 602-Vila Maria, CEP: 02117-0101, Sao Paulo (Brazil); Silva, P. S. C. [Centro de Metrologia das Radiacoes-Instituto de Pesquisas Energeticas e Nucleares, Av. Prof. Lineu Prestes 2242-Cidade Universitaria-CEP 05508 000 Sao Paulo-Brazil (Brazil); Mazzilli, B. P

2008-08-07

4

Mineral resource of the Month: Clay  

USGS Publications Warehouse

Clays were one of the first mineral commodities used by people. Clay pottery has been found in archeological sites that are 12,000 years old, and clay figurines have been found in sites that are even older.

Virta, Robert L.

2010-01-01

5

PROGRAM AND ABSTRACTS FOR CLAY MINERALS SOCIETY  

E-print Network

r PROGRAM AND ABSTRACTS FOR CLAY MINERALS SOCIETY 28th ANNUAL MEETING NI\\SI\\National Aeronautit &II LPI #12;PROGRAM AND ABSTRACTS FOR CLAY MINERALS SOCIETY 28th ANNUAL MEETING Houston, Texas October contains abstracts that have been accepted for presentation at the Clay Minerals Society 28th Annual

Rathbun, Julie A.

6

Mineral resource of the month: clays  

USGS Publications Warehouse

Clays represent one of the largest mineral commodities in the world in terms of mineral and rock production and use. Many people, however, do not recognize that clays are used in an amazingly wide variety of applications. Use continues to increase worldwide as populations and their associated needs increase. Robert Virta, clay and shale commodity specialist for the U.S. Geological Survey, has prepared the following information about clays.

Virta, Robert

2004-01-01

7

Clay mineralogy of weathering rinds and possible implications concerning the sources of clay minerals in soils.  

USGS Publications Warehouse

Weathering rinds on volcanic clasts in Quaternary deposits in the western US contain only very fine-grained and poorly crystalline clay minerals. Rinds were sampled from soils containing well-developed argillic B horizons in deposits approx 105 yr old or more. The clay-size fraction of the rinds is dominated by allophane and iron hydroxy-oxides, whereas the B horizons contain abundant well-crystallized clay minerals. The contrast between the clay mineralogy of the weathering rinds, in which weathering is isolated from other soil processes, and that of the associated soil matrices suggests a need to reassess assumptions concerning the rates at which clay minerals form and the sources of clay minerals in argillic B horizons. It seems that crystalline clay minerals form more slowly in weathering rinds than is generally assumed for soil environments and that the weathering of primary minerals may not be the dominant source of crystalline clay minerals in Middle to Late Pleistocene soil.-A.P.

Colman, S. M.

1982-01-01

8

Surface geochemistry of the clay minerals  

PubMed Central

Clay minerals are layer type aluminosilicates that figure in terrestrial biogeochemical cycles, in the buffering capacity of the oceans, and in the containment of toxic waste materials. They are also used as lubricants in petroleum extraction and as industrial catalysts for the synthesis of many organic compounds. These applications derive fundamentally from the colloidal size and permanent structural charge of clay mineral particles, which endow them with significant surface reactivity. Unraveling the surface geochemistry of hydrated clay minerals is an abiding, if difficult, topic in earth sciences research. Recent experimental and computational studies that take advantage of new methodologies and basic insights derived from the study of concentrated ionic solutions have begun to clarify the structure of electrical double layers formed on hydrated clay mineral surfaces, particularly those in the interlayer region of swelling 2:1 layer type clay minerals. One emerging trend is that the coordination of interlayer cations with water molecules and clay mineral surface oxygens is governed largely by cation size and charge, similarly to a concentrated ionic solution, but the location of structural charge within a clay layer and the existence of hydrophobic patches on its surface provide important modulations. The larger the interlayer cation, the greater the influence of clay mineral structure and hydrophobicity on the configurations of adsorbed water molecules. This picture extends readily to hydrophobic molecules adsorbed within an interlayer region, with important implications for clay–hydrocarbon interactions and the design of catalysts for organic synthesis. PMID:10097044

Sposito, Garrison; Skipper, Neal T.; Sutton, Rebecca; Park, Sung-ho; Soper, Alan K.; Greathouse, Jeffery A.

1999-01-01

9

Dehydration-induced luminescence in clay minerals  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

10

Lipid Peroxidation Induced by Expandable Clay Minerals  

E-print Network

selected. Screening and monitoring of LP was conducted using a thiobarbituric acid reactive substances antibacterial agent(s), (ii) the chemistry was controlled by the clay mineral composition and surface properties

Ahmad, Sajjad

11

Clay Minerals and Italy the Nannobacterial  

E-print Network

ancestors' hometown of Vallelunga, he could see why they came to America! The X-ray work on Italian clays. Geological Society of America Abstracts with Programs, 26(7), A- 508. Folk, R. L. & Lynch, F. L. (1997 in the Alteration of Volcanic Rocks to Clay Minerals in South Italy. Geological Society of America Abstracts

Yang, Zong-Liang

12

Granular preparations of Azotobacter containing clay minerals  

Microsoft Academic Search

Interaction ofAzotobacter chroococcum 20 with clay minerals increased their cell viability at supraoptimal temperatures. Therefore, clay minerals were used to\\u000a develop granular bacterial preparations with high viable cell counts and stable compositions during long-term storage. The\\u000a titers of viable bacteria in the preparations remained 60–70% of the initial level after 12 months of storage.

I. K. Kurdish; L. V. Titova

2000-01-01

13

'Clay hutches': a novel interaction between bacteria and clay minerals.  

PubMed

Biofilm formation on a low-energy substratum floating on the surface of a water column overlying a polychlorinated biphenyl (PCB)-contaminated sandy clay soil was followed by light and electron microscopy. The biofilms that developed consisted of a dense lawn of clay aggregates, each one of which contained one or more bacteria, phyllosilicates and grains of iron oxide material, all held together by bacterial extracellular polysaccharides (EPS). The clay leaflets were arranged in the form of 'houses of cards' and gave the aggregates the appearance of 'hutches' housing the bacteria. Interestingly, although the soil is poor in carbon, and the weakly bioavailable PCBs constitute the principal source of carbon in this system, the bacteria contained electron-transparent structures presumed to be carbon storage granules. These, and the EPS material present in the hutches, indicate that carbon is not limiting in this system and, as PCBs have been found associated with the clay mineral fraction of the floating substratum, the clay particles may serve as carbon shuttles. The interesting possibilities that the 'clay hutches' may represent a 'soil microhabitat', a 'minimal nutritional sphere' and an 'effective survival unit' for autochthonous bacteria are noted. The formation of clay hutches by bacteria would seem to merit further investigation, particularly regarding their roles in bacterial processes in soil and in geological processes. PMID:11220302

Lünsdorf, H; Erb, R W; Abraham, W R; Timmis, K N

2000-04-01

14

Diamagnetic Orientation of Clay Mineral Grains  

Microsoft Academic Search

The orientations of diamagnetic mineral grains in magnetic fields are observed, for the first time, in suspensions of clay minerals such as talc, kaolinite and sericite. The minerals consist of two-dimensional crystal layers which produce intrinsic diamagnetic anisotropy, \\\\varDeltachi, in the unit cell. In the case of talc suspension with the average diameter of phi 2.4 mum and the thickness

Chiaki Uyeda; Tetsuya Takeuchi; Akio Yamagishi; Muneyuki Date

1991-01-01

15

The Link between Clay Mineral Weathering and the Stabilization of  

E-print Network

The Link between Clay Mineral Weathering and the Stabilization of Ni Surface Precipitates R O B E R of the observed increase in dissolution resistance. Thus, clay mineral weathering and the time-dependent release was derived from weathering of the clay mineral surface. A time-dependent extended X

Sparks, Donald L.

16

Identification of clay minerals by infrared spectroscopy and discriminant analysis.  

PubMed

Identification of clay minerals based on chemometric analysis of measured infrared (IR) spectra was suggested. IR spectra were collected using the diffuse reflection technique. Discriminant analysis and principal component analysis were used as chemometric methods. Four statistical models were created for separation and identification of clay minerals. More than 50 samples of various clay mineral standards from different localities were used for the creation of statistical models. The results of this study confirm that the discriminant analysis of IR spectra of clay minerals could provide a powerful tool for identification of clay minerals. Differentiation of muscovite from illite and identification of mixed structures of illite-smectite were achieved. PMID:21144156

Ritz, Michal; Vaculíková, Lenka; Plevová, Eva

2010-12-01

17

Sorption Energy Maps of Clay Mineral Surfaces  

SciTech Connect

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.

Cygan, Randall T.; Kirkpatrick, R. James

1999-07-19

18

Clay mineral type effect on bacterial enteropathogen survival in soil.  

PubMed

Enteropathogens released into the environment can represent a serious risk to public health. Soil clay content has long been known to have an important effect on enteropathogen survival in soil, generally enhancing survival. However, clay mineral composition in soils varies, and different clay minerals have specific physiochemical properties that would be expected to impact differentially on survival. This work investigated the effect of clay materials, with a predominance of a particular mineral type (montmorillonite, kaolinite, or illite), on the survival in soil microcosms over 96 days of Listeria monocytogenes, Salmonella Dublin, and Escherichia coli O157. Clay mineral addition was found to alter a number of physicochemical parameters in soil, including cation exchange capacity and surface area, and this was specific to the mineral type. Clay mineral addition enhanced enteropathogen survival in soil. The type of clay mineral was found to differentially affect enteropathogen survival and the effect was enteropathogen-specific. PMID:24035982

Brennan, Fiona P; Moynihan, Emma; Griffiths, Bryan S; Hillier, Stephen; Owen, Jason; Pendlowski, Helen; Avery, Lisa M

2014-01-15

19

Clay Mineral Formation and Transformation in Rocks and Soils  

Microsoft Academic Search

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

D. D. Eberl; V. C. Farmer; R. M. Barrer

1984-01-01

20

Electrokinetics of pure clay minerals revisited  

SciTech Connect

Clay minerals have long attracted the attention of colloid scientists. This paper considers, specifically, their important role in the transport of various contaminants from land to sea, e.g., metal ions and organic detrital and man-made material in watercourses. Advance in experimental techniques have enabled precise characterization of clays and then electrokinetic experiments at high electrolyte concentrations, such as in seawater. Three of the most important clay minerals encountered in suspended matter in natural waters, montmorillonite, illite, and chlorite, were prepared in a very pure state. Electrokinetic experiments were done in pure aqueous single and complex electrolyte solutions and in solutions in which natural organic matter was simulated using a humic substance, fulvic acid, of defined provenance and properties, typical of riverine waters. An isoelectric point was found at pH 5.0 {+-} 0.2 for chlorite; none were found for illite and montmorillonite. Only Ca{sup 2+} showed a charging effect on chlorite, indeed a reversal of sign from negative to positive at 1 {times} 10{sup {minus}3} mol dm{sup {minus}3}. Addition of fulvic acid affected only chlorite, illite less, and Na montmorillonite not at all.

Sondi, I.; Biscan, J.; Pravdic, V. [Rudjer Boskovic Inst., Zagreb (Croatia). Center for Marine Research] [Rudjer Boskovic Inst., Zagreb (Croatia). Center for Marine Research

1996-03-25

21

Analysis of mixed-layer clay mineral structures  

USGS Publications Warehouse

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.

Bradley, W. F.

1953-01-01

22

[Mechanism of tritium persistence in porous media like clay minerals].  

PubMed

To investigate the mechanisms of tritium persistence in clay minerals, three types of clay soils (montmorillonite, kaolinite and illite) and tritiated water were used in this study to conduct the tritium sorption tests and the other related tests. Firstly, the ingredients, metal elements and heat properties of clay minerals were studied with some instrumental analysis methods, such as ICP and TG. Secondly, with a specially designed fractionation and condensation experiment, the adsorbed water, the interlayer water and the structural water in the clay minerals separated from the tritium sorption tests were fractionated for investigating the tritium distributions in the different types of adsorptive waters. Thirdly, the location and configuration of tritium adsorbed into the structure of clay minerals were studied with infrared spectrometry (IR) tests. And finally, the forces and mechanisms for driving tritium into the clay minerals were analyzed on the basis of the isotope effect of tritium and the above tests. Following conclusions have been reached: (1) The main reason for tritium persistence in clay minerals is the entrance of tritium into the adsorbed water, the interlayer water and the structural water in clay minerals. The percentage of tritium distributed in these three types of adsorptive water are in the range of 13.65% - 38.71%, 0.32% - 5.96%, 1.28% - 4.37% of the total tritium used in the corresponding test, respectively. The percentages are different for different types of clay minerals. (2) Tritium adsorbed onto clay minerals are existed in the forms of the tritiated hydroxyl radical (OT) and the tritiated water molecule (HTO). Tritium mainly exists in tritiated water molecule for adsorbed water and interlayer water, and in tritiated hydroxyl radical for structural water. (3) The forces and effects driving tritium into the clay minerals may include molecular dispersion, electric charge sorption, isotope exchange and tritium isotope effect. PMID:21634173

Wu, Dong-Jie; Wang, Jin-Sheng; Teng, Yan-Guo; Zhang, Ke-Ni

2011-03-01

23

The effect of clay minerals on diasterane/sterane ratios  

NASA Astrophysics Data System (ADS)

To examine the effect of clay minerals on diasterane/sterane ratios, the mineral compositions of three sample sets of sedimentary rocks displaying a wide range of diasterane/sterane ratios were analysed quantitatively. Diasterane/sterane ratios do not to correlate with clay content but depend on the amount of clay relative to the amount of organic matter (clay/TOC ratios). This correlation may explain the high diasterane/sterane ratios in crude oils and extracts derived from certain carbonate source rocks. Based on the concentrations of regular and rearranged steroids in the sample sets, it is proposed that diasterenes are partly reduced to diasteranes and partly degraded during diagenesis in a ratio largely determined by the availability of clay minerals. It is suggested that the hydrogen atoms required for reduction of the diasterenes originate from the water in the interlayers of clay minerals.

van Kaam-Peters, Heidy M. E.; Köster, Jürgen; van der Gaast, Sjierk J.; Dekker, Marlèn; de Leeuw, Jan W.; Sinninghe Damsté, Jaap S.

1998-09-01

24

The formation of goethite and hydrated clay minerals on Mars  

NASA Technical Reports Server (NTRS)

Laboratory studies reported by Huguenin (1973) on the kinetics and mechanism of the photostimulated oxidation of magnetic and preliminary laboratory data on the weathering of silicates, reported herein, are applied to Mars. Basalts in the Martian dark areas are predicted to alter to hydrated Fe(2 plus or minus) depleted clay minerals, minor goethite, and minor to trace amounts of transition metal oxides such as TiO2, MnO2, and Cr2O3 at a rate of 10 to the minus 1.5 plus or minus 1.5 micron/yr. Some Ca-Mg carbonates are also expected to be formed. The clay minerals are predicted to be more silica-rich than the silicate source material, SiO2 contents of 60% or higher being expected, and strongly depleted in Fe(2+). The oxygen, OH, and H2O contents of the bulk weathering product are predicted to be significantly greater than those of the dark-area source materials, whereas the relative bulk metal abundances should be the same.

Huguenin, R. L.

1974-01-01

25

Microbe-Clay Mineral Reactions and Characterization Techniques  

NASA Astrophysics Data System (ADS)

Clays and clay minerals are ubiquitous in soils, sediments, and sedimentary rocks. They play an important role in environmental processes such as nutrient cycling, plant growth, contaminant migration, organic matter maturation, and petroleum production. The changes in the oxidation state of the structural iron in clay minerals, in part, control their physical and chemical properties in natural environments, such as clay particle flocculation, dispersion, swelling, hydraulic conductivity, surface area, cation and anion exchange capacity, and reactivity towards organic and inorganic contaminants. The structural ferric iron [Fe(III)] in clay minerals can be reduced either chemically or biologically. Many different chemical reductants have been tried, but the most commonly used agent is dithionite. Biological reductants are bacteria, including dissimilatory iron reducing prokaryotes (DIRP) and sulfate-reducing bacteria (SRB). A wide variety of DIRP have been used to reduce ferric iron in clay minerals, including mesophilic, thermophilic, and hyperthermophilic prokaryotes. Multiple clay minerals have been used for microbial reduction studies, including smectite, nontronite (iron-rich smectite variety), illite, illite/smectite, chlorite, and their various mixtures. All these clay minerals are reducible by microorganisms under various conditions with smectite (nontronite) being the most reducible. The reduction extent and rate of ferric iron in clay minerals are measured by wet chemistry, and the reduced clay mineral products are typically characterized with chemical methods, X-ray diffraction, scanning and transmission electron microscopy, Mössbauer spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), UV-vis spectroscopy, and synchrotron-based techniques (such as EXAFS). Microbially reduced smectites (nontronites) have been found to be reactive in reducing a variety of organic and inorganic contaminants. Degradable organic contaminants include pesticides, solvents, explosives, and nitroaromatic and polychlorinated compounds. Inorganic contaminants include Cr(VI), U(VI), and Tc(VII). Despite significant efforts, our understanding of mechanisms of chemical and microbial reduction of ferric iron in clay minerals is still limited. While some studies have presented evidence for a solid-state reduction mechanism, others argue that the clay mineral structure dissolves when the extent of reduction is higher (greater than 30 percent). The electron transfer process is also dependent on the reducing agent. While chemical reduction of ferric iron appears to occur at the basal surfaces, bacteria appear to attack clay minerals at the edges.

Dong, H.; Zhang, G.; Ji, S.; Jaisi, D.; Kim, J.

2008-12-01

26

WEATHERING OF IRONBEARING MINERALS IN SOILS AND SAPROLITE ON THE NORTH CAROLINA BLUE RIDGE FRONT: II. CLAY MINERALOGY  

Microsoft Academic Search

The mineralogy of the clay fraction was studied for soils and saprolite on two Blue Ridge Front mountain slopes. The clay fraction contained the weathering products of primary minerals in the mica gneiss and schist parent rocks. Gibbsite is most abundant in the saprolite and residual soil horizons, where only chemical weathering has been operable. In colluvial soil horizons, where

D. D. AMARASIRIWARDENA; S. W. BUOL

27

Browning of pyrogallol as affected by clay minerals  

Microsoft Academic Search

One of the authors, Kumada(1), has presented the idea that humification must be regarded as browning phenomena of organic matter in soils. The browning reaction can be accelerated non-enzymatically as well as enzymatically, and it is considered that humification would be conducted under the influence of some catalytic actions of clay fraction, composed of various kinds of clay minerals, free

Kyoichi Kumada; Hidemasa Kato

1970-01-01

28

Geochemistry of clay minerals for uranium exploration in the Grants mineral belt, New Mexico  

NASA Astrophysics Data System (ADS)

Clay mineralogy studies of ore rocks versus barren rocks in the Grants mineral belt, New Mexico, show that some combination of chlorite (rosette form), illite, mixed-layer illite-montmorillonite, (±Mg-montmorillonite) are penecontemporaneous with uranium minerals in trend ore; these same clay minerals plus kaolinite are related to the roll-type ore near the main redox front of the Grants mineral belt. Clay minerals from barren rocks are characterized by a greater abundance of Na-montmorillonite, kaolinite, and face-to-edge form chlorite. Chlorites from ore zones contain much more vanadium than do chlorites from barren rocks. Trend orr probably formed from southeasterly flowing waters following paleochannels in the Late Jurassic. These deposits are found almost entirely in reduced rocks, and organic carbon may have been an important reductant to remove U-V-U-V-Se-Mo from solution as carbonate from ore zones contains some organic carbon based on stable isotope studies. Uplift, remobilization, and reprecipitation of some of the trend ore resulted in the formation of redistributed ore, some of which possesses a roll-type geometry. Mineralization for the roll-type ore was apparently controlled by sulfide-sulfate equilibria at or near the main redox front in the Grants mineral belt. Trend and roll-type ore possess different assemblages of clay minerals and different trace element abundances. Laramide-age faults cut both trend ore and some roll-type ores. Stack ore is found in Laramide-age fault zones. Limited oxygen isotopic data from clay minerals collected from two mines at Ambrosia Lake in reduced rocks indicate probable preservation of ancient, formational waters and show no evidence of infiltration by young meteoric waters. This information, plus the pre-Laramide-age faults, suggest, but do not unequivocally prove, that the main redox front has been relatively stable since its formation, probably some time in the Cretaceous. Younger encroachment of the redox front in post-Laramide time is proposed by others, however, and the problem is unresolved. Uranium for the deposits was most likely carried in solution as an oxyion, probably as (UO2(CO3)2·2H2O2- or (UO2(HPO4)2)2-, although organic transport cannot be entirely ruled out. Oxyions of vanadium, selenium, molybdenum and possible arsenic and antimony, are interpreted from Eh-pH diagrams to have been segregated and transported with U6+ soluble species and precipitated when a chemically reducing environment was reached. The rare-earth elements are also enriched in ore zones, but is it not clear if they were transported with the U-V-Se-Mo-(As)-(Sb) suite or derived from a more local source.

Brookins, D. G.

1982-03-01

29

The Influences of Clay Minerals on Methane Hydrate Formation  

NASA Astrophysics Data System (ADS)

Natural gas hydrates exist in sediment, either filling sediment pores or locally aggregated as nodular or massive hydrate. The elucidation of the role of the sediment matrix on gas hydrate formation is crucial to understanding the formation mechanism and accumulation of methane hydrate in natural environments. Clay minerals are common constituents of natural sediments. From the results of field and laboratory investigations, as well as theoretical studies, clay minerals are likely to play an important role in controlling the occurrence of natural gas hydrate. However the mechanism of how clay minerals affect hydrate formation is still not well understood. Present research aims at elucidating the role of clay minerals in hydrate formation through experimental investigations. Three types of clays typical of natural sediments have been selected as the test materials: Na-montmorillonite, Ca-montmorillonite, and Kaolinite. Na-montmorillonite and Ca-montmorillonite are 2:1 types, among which interlayer distances (d-spacing) of Na-montmorillonite and Ca-montmorillonite can increase when soaked in water, while the former has much stronger swelling ability than the latter. Kaolinite is 1:1 type, not able to expand its interlayer distance. For the purpose of comparison, quartz was also tested. The results of the P-T stability conditions of methane hydrate in various water-saturated clay minerals, indicated that Ca-montmorillonite and kaolinite are thermodynamic inhibitors for gas hydrate formation, shifting the stability conditions to a regime of relatively lower temperature and higher pressure, while in situ observations on methane hydrate formation in clay minerals by MRI (Magnetic Resonance Imaging) found that clay minerals are kinetic promoters of gas hydrate formation, shortening the induction time greatly as compared to quartz sand.

Kawasaki, T.; Hailong, L.; Ripmeester, J.; Moudrakovski, I.; Zeng, H.; Lee, J.; Fujii, T.; Nakamizu, M.

2006-12-01

30

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

31

Immersion Freezing of Clay Minerals and its Temperature Dependence  

NASA Astrophysics Data System (ADS)

The immersion mode ice nucleation efficiency of clay minerals was investigated using the AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud chamber. Both monodisperse and polydisperse populations of various clay dust samples as well as hematite and Snomax were examined in the temperature range between -4 ?C and -35 ?C. We observed the immersion mode ice nucleation activity of clay minerals to be strongly depended on the temperature. The time dependence of ice formation inferred by the INAS (Ice Nucleation Active Surface-Site) density is investigated and discussed as a function of cooling rates and by comparing to predicted nucleation rates (i.e., classical nucleation theory with ?-probability density function nucleation scheme). Ice residuals collected through a newly developed pumped counterflow virtual impactor have also been examined by electron microscope analyses to seek the chemical and physical identity of ice nuclei in clay minerals. Brief comparisons of AIDA measurement to the measurements with mobile ice nucleation counters are also presented.

Hiranuma, Naruki; Möhler, Ottmar; Bingemer, Heinz; Bundke, Ulrich; Cziczo, Daniel; Danielczok, Anja; Ebert, Martin; Garimella, Sarvesh; Hoffmann, Nadine; Höhler, Kristina; Kanji, Zamin; Kiselev, Alexei; Raddatz, Michael; Stetzer, Olaf

2013-04-01

32

Microbial Impacts on Clay Mineral Transformation and Reactivity  

NASA Astrophysics Data System (ADS)

Clays and clay minerals are ubiquitous in soils, sedimentary rocks, and pelagic oozes. They play important roles in environmental processes such as nutrient cycling, plant growth, contaminant migration, organic matter maturation, and petroleum production. Iron is a major constituent in clay minerals, and its mobility and stability in different environmental processes is, in part, controlled by the oxidation state. Recent studies have shown that biological reduction of structural Fe(III) in clay minerals can change the physical and chemical properties of clay minerals, such as swelling, cation exchange and fixation capacity, specific surface area, color, and magnetic exchange interactions. As a result of biological reduction of Fe(III), clay minerals also undergo mineral transformations, such as dissolution of smectite and precipitation of illite, siderite and vivianite. These chemical, structural and mineralogical changes of clay minerals have a profound effect on clay mineral reactivity, such as their reactivity with organic and inorganic (i.e., heavy metals and radionuclides) contaminants. Our latest data show that biologically reduced nontronite (a smectite variety) is much more effective in reducing soluble and mobile Tc(VII) to Tc(IV) than unreduced nontronite. The reduced Tc(IV) is insoluble in groundwater and soil and thus is immobile. Biologically reduced nontronite can be prepared by microbially reducing Fe(III) in nontronite by Shewanella putrefaciens in the absence of oxygen. Approximately 30% of structurally Fe(III) can be reduced in this manner. Biogenic Fe(II) can then serve as an electron donor to reduce Tc(VII). Nearly all Fe(II) is available to reduce Tc(VII), with the rate of reduction (typically within weeks) possibly depending on the speciation of Fe(II) (surface sorbed Fe(II) vs. structural Fe(II)). Further investigations are underway to further assess the reversibility of Tc reduction upon exposure to oxygen and to elucidate Tc reduction kinetics. These preliminary results have important implications for in-situ bioremediation efforts, where either chemically or biologically reduced clay minerals can be introduced into a contaminant site for removing heavy metals and radionuclides in groundwater aquifers.

Dong, H.; Jaisi, D.; Fredrickson, J.; Plymale, A.

2006-05-01

33

Intercalation of Trichloroethene by Sediment-Associated Clay Minerals  

SciTech Connect

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.

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

2013-01-01

34

INTERCALATION OF TRICHLOROETHENE BY SEDIMENT-ASSOCIATED CLAY MINERALS  

PubMed Central

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

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

2012-01-01

35

Environmental applications of radiation-induced defects in clay minerals  

NASA Astrophysics Data System (ADS)

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.

Allard, T.

2011-12-01

36

Fluoride content of clay minerals and argillaceous earth materials  

USGS Publications Warehouse

A reliable method, utilizing a fluoride ion-selective electrode, is described for the determination of fluoride in clays and shales. Interference by aluminum and iron is minimal. The reproducibility of the method is about ??5% at different levels of fluoride concentration. Data are presented for various clay minerals and for the <2-??m fractions of marine and nonmarine clays and shales. Fluoride values range from 44 ppm (0.0044%) for nontronite from Colfax, WA, to 51,800 ppm (5.18%) for hectorite from Hector, CA. In general, clays formed under hydrothermal conditions are relatively high in fluoride content, provided the hydrothermal waters are high in fluoride content. Besides hectorite, dickite from Ouray, CO, was found to contain more than 50 times as much fluoride (6700 ppm) as highly crystalline geode kaolinite (125 ppm). The clay stratum immediately overlying a fluorite mineralized zone in southern Illinois was found to have a higher fluoride content than the same stratum in a nonmineralized zone approximately 1 mile away. Nonmarine shales in contact with Australian coals were found to be lower in fluoride content than were marine shales in contact with Illinois coals. It is believed that, in certain instances, peak shifts on DTA curves of similar clay minerals are the result of significant differences in their fluoride content. ?? 1977.

Thomas, J., Jr.; Glass, H.D.; White, W.A.; Trandel, R.M.

1977-01-01

37

Immersion Freezing of Clay Minerals and its Time Dependence  

NASA Astrophysics Data System (ADS)

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.

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

38

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

SciTech Connect

“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.

Randall T. Cygan

2007-06-01

39

[Occurrence relationship between iron minerals and clay minerals in net-like red soils: evidence from X-ray diffraction].  

PubMed

The high purity of clay minerals is a key factor to reconstruct the palaeoclimate in clay mineralogy, however, the existence of iron minerals (such as goethite and hematite) and organics lead to the intergrowth of clay minerals and other minerals, producing other mineral impurities in enriched clay minerals. Although the removal of organics in soil sediments has been fully investigated, the occurrence state of iron minerals remains controversial, hindering the preparation of high-purity clay minerals. Therefore, the occurrence relationship of iron minerals and clay minerals in Jiujiang net-like red soils of the middle to lower reaches of the Yangtze River was investigated using the sequential separation method, which provided some implications for the removal of iron minerals in soil sediments. The results indicated that goethite and hematite were mostly absorbed on the surface of hydroxy-interlayered smectite and illite in the form of films, and the rest were absorbed by kaolinite. PMID:23841442

Yin, Ke; Hong, Han-Lie; Han, Weni; Ma, Yu-Bo; Li, Rong-Biao

2013-04-01

40

First Direct Detection of Clay Minerals on Mars  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

41

Iodide interactions with clay minerals: Batch and diffusion studies  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

42

Geochemical dynamics of cesium sorption by selected clay minerals  

Microsoft Academic Search

This study focuses on the interactions of cesium with selected clay minerals. Cesium is of interest as it is a chief component of high level radioactive waste. Primarily, the thermodynamics and kinetics of Cs exchange reactions were investigated to determine the preference for Cs of a kaolinite, illite, and vermiculite. Thermodynamic studies indicated that Cs was most strongly preferred by

Noll

1989-01-01

43

Removal of diphenhydramine from water by swelling clay minerals.  

PubMed

Frequent detection of pharmaceuticals in surface water and wastewater attracted renewed attention on studying interactions between pharmaceuticals and sludge or biosolids generated from wastewater treatment. Less attention was focused on studying interactions between pharmaceuticals and clay minerals, important soil and sediment components. This research targeted on investigating interactions between diphenhydramine (DPH), an important antihistamine drug, and a montmorillonite, a swelling clay, in aqueous solution. Stoichiometric desorption of exchangeable cations accompanying DPH adsorption confirmed that cation exchange was the most important mechanism of DPH uptake by the swelling clay. When the solution pH was below the pK(a) of DPH, its adsorption on the swelling clay was less affected by pH. Increasing solution pH above the pK(a) value resulted in a decrease in DPH adsorption by the clay. An increase in d(001) spacing at a high DPH loading level suggested interlayer adsorption, thus, intercalation of DPH. The results from this study showed that swelling clays are a good environmental sink for weak acidic drugs like DPH. In addition, the large cation exchange capacity and surface area make the clay a good candidate to remove cationic pharmaceuticals from the effluent of wastewater treatment facilities. PMID:21570085

Li, Zhaohui; Chang, Po-Hsiang; Jiang, Wei-Teh; Jean, Jiin-Shuh; Hong, Hanlie; Liao, Libing

2011-08-01

44

RIETVELD REFINEMENT OF REAL STRUCTURE PARAMETERS OF DISORDERED CLAY MINERALS IN  

E-print Network

-conventional hydrocarbons in Germany) Germany's potential for shale oil and shale gas NIKO seal gas-rich shale shale: sedimentary rock which contains quartz, carbonates and clay minerals #12;clay minerals in shales quartz

Magee, Joseph W.

45

Clay minerals in Alpine Fault gouge: First results from the DFDP-1B pilot hole  

NASA Astrophysics Data System (ADS)

Clay mineralization is increasingly recognized as a key process along fault systems in the upper crust. The Alpine Fault in New Zealand is a major active fault zone with locally large earthquakes. Samples from this fault zone offer excellent opportunity to investigate recent and ancient rupture zones, and the mechanical role of clay mineral transformations and fluid-rock interactions in particular. The Alpine Fault drilling project (DFDP-project) on the South Island of New Zealand sampled two shallow pilot holes; DFDP-1A was drilled down to 100.6 m and DFDP-1B drilled down to 151.4 m. Five samples from borehole DFDP-1B have been investigated by X-ray diffraction, X-ray texture goniometry and electron microscopy. These samples were taken at ~143.3 m (sections 69_2 to 69_2) and ~128.1 m depth (sections 59_1 to 59_1); the latter is the area of principal slip. The bulk rock mineralogy shows similar compositions in all samples with quartz, phyllosilicates (muscovite, chlorite), calcite, zeolite and clay minerals; the dominant clay phases in all samples are illite and chlorite. Importantly, abundant discrete smectite is uniquely present in gouge zones at sections 69_2 (~143.4 m) and 59_1 (~128.1 m). Smectite was likely formed by dissolution-precipitation reactions during displacement and movement of aqueous fluids along permeable fractures, at the expense of host rock minerals. Electron microscopy of fault gouge at section 69_2 shows small illite and smectite particles with pseudo-hexagonal shapes and variable amounts of K, Ca, Mg and Fe, growing adjacent to each other. Some distinct illite and smectite mineral veins form epitaxially on quartz-feldspar mineral surfaces. Clay fabric intensity, measured by X-ray goniometry, is higher outside the gouge zones (true cataclasite, section 69_1) with average fabric intensities of m.r.d. 3.5. Both gouge zones at sections 59_2 and 69_1 exhibit uniformly weak fabrics for illite and chlorite (m.r.d. ~2.5 on average). The weak fabrics in fault gouge support the interpretation that clay fabric development in shallow fault rocks is a function of authigenic mineral growth and not stress-induced particle orientation. The unique localization of smectite in fault gouge indicates that swelling clay minerals may dominate fault behavior at shallow depth, and that temporal and fluid histories may be obtained from study of these fault rocks and samples from planned, deeper drilling.

van der Pluijm, B. A.; Schleicher, A. M.

2012-12-01

46

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

SciTech Connect

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.

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

1993-06-01

47

Ice nucleation efficiency of clay minerals in the immersion mode  

NASA Astrophysics Data System (ADS)

Emulsion and bulk freezing experiments were performed to investigate immersion ice nucleation on clay minerals in pure water, using various kaolinites, montmorillonites, illites as well as natural dust from the Hoggar Mountains in the Saharan region. Differential scanning calorimeter measurements were performed on three different kaolinites (KGa-1b, KGa-2 and K-SA), two illites (Illite NX and Illite SE) and four natural and acid-treated montmorillonites (SWy-2, STx-1b, KSF and K-10). The emulsion experiments provide information on the average freezing behaviour characterized by the average nucleation sites. These experiments revealed one to sometimes two distinct heterogeneous freezing peaks, which suggest the presence of a low number of qualitatively distinct average nucleation site classes. We refer to the peak at the lowest temperature as "standard peak" and to the one occurring in only some clay mineral types at higher temperatures as "special peak". Conversely, freezing in bulk samples is not initiated by the average nucleation sites, but by a very low number of "best sites". The kaolinites and montmorillonites showed quite narrow standard peaks with onset temperatures 238 Kclay minerals strongly depend on the amount of clay mineral present per droplet and on the exact type (location of collection and pre-treatment) of the clay mineral. We suggest that apparently contradictory results obtained by different groups with different setups are indeed in good agreement when only clay minerals of the same type and amount per droplet are compared. The natural sample from the Hoggar Mountains, a region whose dusts have been shown to be composed mainly of illite, showed very similar freezing characteristics (standard and best) to the illites. Relating the concentration of best IN to the dust concentration in the atmosphere suggested that the best IN in the Hoggar sample would be common enough downwind of their source region to account for ambient IN number densities in the temperature range of 250-260 K at least during dust events.

Pinti, V.; Marcolli, C.; Zobrist, B.; Hoyle, C. R.; Peter, T.

2012-07-01

48

Geochemical dynamics of cesium sorption by selected clay minerals  

SciTech Connect

This study focuses on the interactions of cesium with selected clay minerals. Cesium is of interest as it is a chief component of high level radioactive waste. Primarily, the thermodynamics and kinetics of Cs exchange reactions were investigated to determine the preference for Cs of a kaolinite, illite, and vermiculite. Thermodynamic studies indicated that Cs was most strongly preferred by Ca saturated clays. Of the three minerals studied, illite proved to be the most effective in adsorbing Cs as indicated by the Vanselow Selectivity Coefficients (k{sub v}). The k{sub v} values for illite ranged from 5.87 to over 10{sup 10}, depending on the mineral and saturating cation. Kinetics experiments proved to be the most interesting. On 2:1 clay minerals (illite and vermiculite), two simultaneous reactions are postulated. The first, and faster of the two reactions, is believed to correspond to Cs adsorption on surface planar sites. The second reaction may be the adsorption of Cs on interlayer and wedge exchange sites. Kaolinite only shows a single reaction since it is a 1:1 clay mineral. Rate coefficients were calculated and the first reaction was found to be on the order of one magnitude greater than the second reaction. The reactions on kaolinite were similar to this faster reaction. Desorption data indicated that the rate of desorption was one or more orders of magnitude less than the corresponding adsorption rate. It is important to note, however, that studies on the effect of temperature indicated that Arrhenius behavior is not followed in many of these experiments. It is postulated that changes in cation radius ratio, or the availability of exchange sites is causing this Anti-Arrhenius behavior. Finally, it is concluded that illite exhibits the greatest preference for the adsorption of Cs.

Noll, M.R.

1989-01-01

49

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

50

Reversibility of soil forming clay mineral reactions induced by plant - clay interactions  

NASA Astrophysics Data System (ADS)

Recent data based upon observations of field experiments and laboratory experiments suggest that changes in phyllosilicate mineralogy, as seen by X-ray diffraction analysis, which is induced by plant action can be reversed in relatively short periods of time. Changes from diagenetic or metamorphic mineral structures (illite and chlorite) to those found in soils (mixed layered minerals in the smectite, hydroxy-interlayer mineral and illites) observed in Delaware Bay salt marsh sediments in periods of tens of years and observed under different biologic (mycorhize) actions in coniferous forests in the soil environment can be found to be reversed under other natural conditions. Reversal of this process (chloritisation of smectitic minerals in soils) has been observed in natural situations over a period of just 14 years under sequoia gigantia. Formation of smectite minerals from illite (potassic mica-like minerals) has been observed to occur under intensive agriculture conditions over periods of 80 years or so under intensive zea mais production. Laboratory experiments using rye grass show that this same process can be accomplished to a somewhat lesser extent after one growing season. However experiments using alfalfa for 30 year growing periods show that much of the illite content of a soil can be reconstituted or even increased. Observations on experiments using zea mais under various fertilizer and mycorhize treatments indicate that within a single growing season potassium can be extracted from the clay (illite layers) but at the end of the season the potassium can be restored to the clay structures and more replaced that extracted. Hence it is clear that the change in clay mineralogy normally considered to be irreversible, illite to smectite or chlorite to smectite observed in soils, is a reversible process where plant systems control the soil chemistry and the soil mineralogy. The changes in clay mineralogy concern mostly the chemical composition of the interlayer ion population of a 2:1 clay structure. However the differences in interlayer ion chemistry give us such mineral names as chloritic hydroxyinterlayered mineral (Mg, OH interlayer), illite (K interlayer), and smectite (essentially hydrated Ca interlayer ions). Extraction of these interlayer ions can be reversed by chemistry engendered by plant regimes.

Barré, P.; Velde, B.

2012-04-01

51

Ice nucleation efficiency of clay minerals in the immersion mode  

NASA Astrophysics Data System (ADS)

Emulsion and bulk freezing experiments were performed to investigate immersion ice nucleation on clay minerals in pure water, using various kaolinites, montmorillonites, illites as well as natural dust from the Hoggar Mountains in the Saharan region. DSC (differential scanning calorimeter) measurements were performed on the kaolinites KGa-1b and KGa-2 from the Clay Mineral Society and kaolinite from Sigma-Aldrich; the montmorillonites SWy-2 and STx-1b from the Clay Mineral Society and the acid treated montmorillonites KSF and K-10 from Sigma Aldrich; the illites NX and SE from Arginotec. The emulsion experiments provide information on the average freezing behaviour characterized by the average nucleation sites. These experiments revealed one to two distinct heterogeneous freezing peaks, which suggest the presence of a low number of qualitatively distinct average nucleation site classes. We refer to the peak at the lowest temperature as "standard peak" and to the one at higher temperatures as "special peak". Conversely, freezing in bulk samples is not initiated by the average nucleation sites, but by a very low number of "best sites". The kaolinites showed quite narrow standard peaks with onset temperatures 239 K < Tonstd < 242 K and best sites with averaged median freezing temperature Tmedbest = 257 K. Only the kaolinite from Sigma Aldrich featured a special peak with freezing onset at 248 K. The illites showed broad standard peaks with freezing onsets at 244 K < Tonstd < 246 K and best sites with averaged median freezing temperature Tmedbest = 262 K. Montmorillonites had standard peaks with onsets 238 K < Tonstd < 240 K and best sites with Tmedbest=257 K. SWy-2, M K10, and KSF featured special peaks with onsets at Tonspcl=247, 240, and 242 K, respectively. M K10 and KSF both from Sigma Aldrich had less intense standard peaks compared to the ones from the Clay Mineral Society suggesting that a fraction of the standard sites are lost by the acid treatment. The acid treatment had however, no evident effect on best sites. Our investigations demonstrate that immersion freezing temperatures of clay minerals strongly depend on the amount of clay mineral present per droplet and on the exact type (location of collection and pre-treatment) of the clay mineral. We suggest that apparently contradictory results obtained by different groups with different setups can indeed be brought into good agreement when only clay minerals of the same type and amount per droplet are compared. The natural sample from the Hoggar Mountains, a region whose dusts have been shown to be composed mainly of illite, showed very similar freezing characteristics to the illites with freezing peak onsets 247 K < Tonstd < 248 K for the average and Tmedbest = 261 K for the best sites. Relating the concentration of best IN to the dust concentration in the atmosphere suggested that the best IN in the Hoggar sample would be common enough downwind of their source region to account for ambient IN number densities in the temperature range of 250-260 K at least during dust events.

Pinti, V.; Marcolli, C.; Zobrist, B.; Hoyle, C. R.; Peter, T.

2012-01-01

52

Some engineering aspects of homoionized mixed clay minerals.  

PubMed

Many studies have been conducted to investigate the physicochemical behavior of pure clay minerals and predict their engineering performance in the field. In this study, the physicochemical properties of an artificial mixture of different clay minerals namely, 40-50% montmorillonite, 20-30% illite and 10-15% kaolin were investigated. The mixture was homoionized with sodium, Na+; calcium, Ca2+; and aluminum, Al3+. The engineering properties studied were consistency limits, sediment volume, compressibility behavior, and hydraulic conductivity. The results revealed that the liquid, plastic and shrinkage limits of soil increased with increasing cation valence. The hydraulic conductivity of the soil also increased with an increase in the valence of the cation at any given void ratio. Aluminum and sodium treated clays had the highest and the lowest modified compression index values, respectively. Furthermore, trivalent cation saturated clayey soil consolidates three times faster than that of monovalent and two times faster than that of divalent. These properties of the soils determined were, in general, similar to those of kaolinite rather than those of montmorillonite. The comparison of the results obtained with the published data in the literature revealed that the physicochemical behavior of the tested clay soil was, in general, similar to that of kaolinite. PMID:12733811

Oren, Ali Hakan; Kaya, Abidin

2003-05-01

53

Immersion freezing of clay minerals and bacterial ice nuclei  

NASA Astrophysics Data System (ADS)

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 populations of (1) various clay dust samples as well as (2) Snomax® (a proxy for bacterial ice nucleators) and (3) hematite are examined in the temperature range between -4°C and -35°C. The temperature dependence of ice formation inferred by the INAS (Ice Nucleation Active Surface-Site) density is investigated and discussed as a function of cooling rate and by comparing to predicted nucleation rates (i.e., classical nucleation theory with ?-probability density function nucleation scheme). To date, we observe that maintaining constant AIDA temperature does not trigger any new ice formation during the immersion freezing experiments with clay dust samples and Snomax®, implying strong temperature dependency (and weak time dependency) within our time scales and conditions of experiments. Ice residuals collected through a newly developed PCVI (Pumped ounter-flow Virtual Impactor) with the 50% cut size diameter of 10 to 20 ?m have also been examined by electron microscope analyses to seek the chemical and physical identity of ice nuclei in clay minerals. In addition to the AIDA results, complementary measurements with mobile ice nucleation counters are also presented.

Hiranuma, Naruki; Möhler, Ottmar; Bingemer, Heinz; Bundke, Ulrich; Cziczo, Daniel J.; Danielczok, Anja; Ebert, Martin; Garimella, Sarvesh; Hoffmann, Nadine; Höhler, Kristina; Kanji, Zamin A.; Kiselev, Alexei; Raddatz, Michael; Stetzer, Olaf

2013-05-01

54

Sorption characteristics of 137 Cs onto clay minerals: Effect of mineral structure and ionic strength  

Microsoft Academic Search

The sorption behavior of137Cs onto kaolinite, bentonite, illite, and zeolite was studied at different ionic strengths of Na+, K+, Ca2+. A significant effect of ionic strengths on the sorption has been observed. Clay minerals with 21 structure (bentonite, illite) showed much higher sorption than that of 11 structure (kaolinite). Zeolite showed high selectivity for137Cs sorption. Sorption behavior of137Cs on clay

Young-Hwan Cho; Chan-Ho Jeong; Pil-Soo Hahn

1996-01-01

55

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

SciTech Connect

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.

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

2011-07-01

56

New techniques for clay mineral identification by remote sensing  

SciTech Connect

In the past three years there have been major advancements in our ability to identify clay minerals by remote sensing. Multispectral scanners, including NASA's Thematic Mapper Simulator (analog for Landsat-D Thematic Mapper) have had several broad-band channels in the wavelength region of 1.0 to 2.5 ..mu..m. In particular, the wavelength region 2.0 to 2.5 ..mu..m contains diagnostic spectral-absorption features for most layered silicates. Computer processing of image data obtained with these scanners has allowed the identification of the presence of clay minerals, without, however, being able to identify specific mineralogies. Studies of areas with known hydrocarbon deposits and porphyry copper deposits have demonstrated the value of this information for rock-type discrimination and recognition of hydrothermal alteration zones. Non-imaging, narrow-band radiometers and spectrometers have been used in the field, from aircraft, and from space to identify individual mineralogical constituents. This can be done because of diagnostic spectral absorption features in the 2.0 to 2.5 ..mu..m region characteristic of different clay types. Preliminary analysis of SMIRR data over Egypt showed that kaolinite, carbonate rocks, and possibly montmorillonite, could be identified directly. Plans are currently under way for development of narrow-band imaging systems which will be capable of producing maps showing the surface distribution of individual clay types. This will represent a major step in remote sensing, by allowing unique identification of minerals rather than the current ability only to discriminate among materials. Applications of this technology will provide geologists with a powerful new tool for resource exploration and general geologic mapping problems.

Abrams, M.J.; Goetz, A.F.H.; Lang, H.

1983-03-01

57

Program and Abstracts for Clay Minerals Society 28th Annual Meeting  

NASA Technical Reports Server (NTRS)

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.

1991-01-01

58

Adsorption of nitrobenzene and n -pentanol from aqueous solution on hydrophilic and hydrophobic clay minerals  

Microsoft Academic Search

The sorption of nitrobenzene andn-pentanol from dilute aqueous solution on swelling clay minerals and their organophilized derivatives (organo clays) was studied. Adsorption excess isotherms were obtained by the immersion method. The basal spacings of the clay minerals were determined by X-ray diffraction measurements. By combining these two independent methods, composition and structure of the interlamellar space could be calculated. On

I. Dékány; A. Farkas; I. Regdon; E. Klumpp; H. D. Narres; M. J. Schwuger

1996-01-01

59

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

E-print Network

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

Paris-Sud XI, Université de

60

Adsorption and separation of proteins by a smectitic clay mineral.  

PubMed

The adsorption of proteins by a smectitic clay mineral was investigated. The clay used in this study is a mixture of montmorillonite and amorphous SiO(2). Due to the high porosity the montmorillonite units are accessible for protein adsorption. The amorphous silica prevents the montmorillonite from swelling and allows column packing. Protein adsorption was performed at different pH under static conditions. Furthermore, static capacities were determined. The material reveals high adsorption capacities for proteins under static conditions (270-408 mg/g), whereby proteins are mainly adsorbed via electrostatic interactions. The Freundlich isotherm is suggested as an adsorption model. For desorption a pH shift was found to be most effective. Binding and elution of human serum albumin and ovalbumin were tested under dynamic conditions. Dynamic capacities of about 40 mg/g for ovalbumin at 764 cm/h were found. The clay mineral provides suitable properties for the application as cost-efficient, alternative separation material. PMID:20340034

Ralla, Kathrin; Sohling, Ulrich; Riechers, Daniel; Kasper, Cornelia; Ruf, Friedrich; Scheper, Thomas

2010-09-01

61

Report on "Methodologies for Investigating Microbial-Mineral Interactions: A Clay Minerals Society Short Course"  

SciTech Connect

A workshop entitled, “Methods of Investigating Microbial-Mineral Interactions,” was held at the Clay Minerals Society meeting at the Pacific Northwest National Laboratory in Richland, WA on June 19, 2004. The workshop was organized by Patricia A. Maurice (University of Notre Dame) and Lesley A. Warren (McMaster University, CA). Speakers included: Dr. P. Bennett, Dr. J. Fredrickson (PNNL), Dr. S. Lower (Ohio State University), Dr. P. Maurice, Dr. S. Myneni (Princeton University), Dr. E. Shock (Arizona State), Dr. M. Tien (Penn State), Dr. L. Warren, and Dr. J. Zachara (PNNL). There were approximately 75 attendees at the workshop, including more than 20 students. A workshop volume was published by the Clay Minerals Society [Methods for Study of Microbe-Mineral Interactions (2006), CMS Workshop Lectures, vol. 14?(Patricia A. Maurice and Leslie A. Warren, eds.) ISBN 978-1-881208-15-0, 166 pp.

Patricia A. Maurice

2010-02-08

62

Aqueous suspensions of natural swelling clay minerals. 2. Rheological characterization.  

PubMed

We report in this article a comprehensive investigation of the viscoelastic behavior of different natural colloidal clay minerals in aqueous solution. Rheological experiments were carried out under both dynamic and steady-state conditions, allowing us to derive the elasticity and yield stress. Both parameters can be renormalized for all sizes, ionic strength, and type of clay using in a first approach only the volume of the particles. However, applying such a treatment to various clays of similar shapes and sizes yields differences that can be linked to the repulsion strength and charge location in the swelling clays. The stronger the repulsive interactions, the better the orientation of clay particles in flows. In addition, a master linear relationship between the elasticity and yield stress whose value corresponds to a critical deformation of 0.1 was evidenced. Such a relationship may be general for any colloidal suspension of anisometric particles as revealed by the analysis of various experimental data obtained on either disk-shaped or lath- and rod-shaped particles. The particle size dependence of the sol-gel transition was also investigated in detail. To understand why suspensions of larger particles gel at a higher volume fraction, we propose a very simplified view based on the statistical hydrodynamic trapping of a particle by an another one in its neighborhood upon translation and during a short period of time. We show that the key parameter describing this hydrodynamic trapping varies as the cube of the average diameter and captures most features of the sol-gel transition. Finally, we pointed out that in the high shear limit the suspension viscosity is still closely related to electrostatic interactions and follows the same trends as the viscoelastic properties. PMID:21591697

Paineau, Erwan; Michot, Laurent J; Bihannic, Isabelle; Baravian, Christophe

2011-06-21

63

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

NASA Astrophysics Data System (ADS)

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.

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

64

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

E-print Network

of kaolinite and illite, and a small amount of halloysite. A little quartz was present in the fine fraction of all samples studied. Percentages of the clay minerals were estimated from X-ray diffraction peak intensities, and from cation-exchange capacity... their mark in the prevailing clay minerals assemblages in sedimentary rocks. Prior to these reports the most extensive studies of marine clay minerals were those of Correns (l937)> who with his associates found REVIEW OF LITERATURE 6 mica (illite...

McAllister, Raymond Francis

2013-10-04

65

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

E-print Network

of spray-dried specimen from 5 grams starting materials ?? 62 4.6 Rietveld, total-sample quantification results ??????????? 66 4.7 CEC of major cation-adsorbing clay mineral groups ???????.. 68 4.8 Measured CEC of aggregate clay fractions and -40... from the feldspar minerals, which then altered to kaolinites and illites. Concretes containing more weathered granites with greater clay mineral content exhibited higher drying shrinkage and lower compressive strength than those with unweathered...

Russell, George 1983-

2012-11-28

66

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

67

Radiolysis of alanine adsorbed in a clay mineral  

SciTech Connect

Optical activity in molecules is a chemical characteristic of living beings. In this work, we examine the hypothesis of the influence of different mineral surfaces on the development of a specific chirality in organic molecules when subjected to conditions simulating the primitive Earth during the period of chemical evolution. By using X-ray diffraction techniques and HPLC/ELSD to analyze aqueous suspensions of amino acids adsorbed on minerals irradiated in different doses with a cobalt-60 gamma source, the experiments attempt to prove the hypothesis that some solid surfaces (like clays and meteorite rocks) may have a concentration capacity and protective role against external sources of ionizing radiation (specifically {gamma}-ray) for some organic compounds (like some amino acids) adsorbed on them. Preliminary results show a slight difference in the adsorption and radiolysis of the D-and L-alanine.

Aguilar-Ovando, Ellen Y.; Negron-Mendoza, Alicia [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico (UNAM), Circuito Exterior s/n, Ciudad Universitaria, Apartado Postal 70-543, Deleg. Coyoacan, C.P. 04510 (Mexico)

2013-07-03

68

Radiolysis of alanine adsorbed in a clay mineral  

NASA Astrophysics Data System (ADS)

Optical activity in molecules is a chemical characteristic of living beings. In this work, we examine the hypothesis of the influence of different mineral surfaces on the development of a specific chirality in organic molecules when subjected to conditions simulating the primitive Earth during the period of chemical evolution. By using X-ray diffraction techniques and HPLC/ELSD to analyze aqueous suspensions of amino acids adsorbed on minerals irradiated in different doses with a cobalt-60 gamma source, the experiments attempt to prove the hypothesis that some solid surfaces (like clays and meteorite rocks) may have a concentration capacity and protective role against external sources of ionizing radiation (specifically ?-ray) for some organic compounds (like some amino acids) adsorbed on them. Preliminary results show a slight difference in the adsorption and radiolysis of the D-and L-alanine.

Aguilar-Ovando, Ellen Y.; Negrón-Mendoza, Alicia

2013-07-01

69

Role of clay minerals in the physicomechanical deterioration of sandstone  

NASA Astrophysics Data System (ADS)

Extensive weathering suffered by sandstone in natural outcrops as well as in historical buildings could be attributed among other mechanisms to the action of wetting and drying cycles. We have recently shown how to quantify the stresses generated during such cycles to determine whether damage can take place. This procedure is further developed in this paper and applied to the Tarifa sandstone, a sandstone with a 7 wt % content of clay minerals and used in the main façade of the church of San Mateo in Tarifa (Cádiz, Spain) for which the relevant material properties are measured. It is shown that tensile stresses during drying can cause cracking of thin elements and that shear forces can cause buckling of wetted surfaces more generally, eventually resulting in scaling and/or contour scaling. These predictions are supported by visual observations on the monument showing degradation patterns characteristic of those types of damage. Similar weathering forms have been observed in natural sandstone landscapes. Application of swelling inhibitors (e.g., cationic surfactants) that selectively adsorb on the clay basal planes, results in a substantial swelling reduction. This confirms that the swelling clays typically present in sandstone are pivotal for its weathering and indicates that swelling inhibitors are a potentially valuable treatment to prevent or minimize damage to stone. The circumstances that would lead to weathering are discussed in relation to sandstone material properties in the wet and dry state. Clay-bearing stones are shown to exhibit softening during wetting, as well as viscoelastic stress relaxation, which is expected to limit the extent of damage. These results may aid in the better understanding of sandstone weathering both in nature and in urban environment and may help develop conservation methods to mitigate wetting/drying damage in ornamental sandstone or to prevent pore plugging in reservoir sandstones.

JiméNez-GonzáLez, Inmaculada; RodríGuez-Navarro, Carlos; Scherer, George W.

2008-06-01

70

Soft X-ray spectromicroscopy study of mineral-organic matter associations in pasture soil clay fractions.  

PubMed

There is a growing acceptance that associations with soil minerals may be the most important overarching stabilization mechanism for soil organic matter. However, direct investigation of organo-mineral associations has been hampered by a lack of methods that can simultaneously characterize organic matter (OM) and soil minerals. In this study, STXM-NEXAFS spectroscopy at the C 1s, Ca 2p, Fe 2p, Al 1s, and Si 1s edges was used to investigate C associations with Ca, Fe, Al, and Si species in soil clay fractions from an upland pasture hillslope. Bulk techniques including C and N NEXAFS, Fe K-edge EXAFS spectroscopy, and XRD were applied to provide additional information. Results demonstrated that C was associated with Ca, Fe, Al, and Si with no separate phase in soil clay particles. In soil clay particles, the pervasive C forms were aromatic C, carboxyl C, and polysaccharides with the relative abundance of carboxyl C and polysaccharides varying spatially at the submicrometer scale. Only limited regions in the soil clay particles had aliphatic C. Good C-Ca spatial correlations were found for soil clay particles with no CaCO3, suggesting a strong role of Ca in organo-mineral assemblage formation. Fe EXAFS showed that about 50% of the total Fe in soils was contained in Fe oxides, whereas Fe-bearing aluminosilicates (vermiculite and Illite) accounted for another 50%. Fe oxides in the soil were mainly crystalline goethite and hematite, with lesser amounts of poorly crystalline ferrihydrite. XRD revealed that soil clay aluminosilicates were hydroxy-interlayered vermiculite, Illite, and kaolinite. C showed similar correlation with Fe to Al and Si, implying a similar association of Fe oxides and aluminosilicates with organic matter in organo-mineral associations. These direct microscopic determinations can help improve understanding of organo-mineral interactions in soils. PMID:24837340

Chen, Chunmei; Dynes, James J; Wang, Jian; Karunakaran, Chithra; Sparks, Donald L

2014-06-17

71

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

E-print Network

that mineral sorption affects transport of natural organic matter to bottom water and to sediments (before sedimentation)? What is the behaviour of clay/organic matter complexes in the deep water? DoesSorption of organic matter on clay minerals in aquatic system and influence on sedimentary organic

Paris-Sud XI, Université de

72

Hydrothermal Effects on Cesium Sorption and Fixation by Clay Minerals and Shales  

Microsoft Academic Search

The effects of hydrothermal conditions on the sorption and fixation of cesium by various clay minerals and shales were investigated. Hydrothermal heating, which may be expected in a radioactive waste repository, altered the clay minerals and shales and led to a decrease in their cation-exchange ca- pacity. Cesium sorption greatly decreased in micaceous vermiculite and in well-crystallized illites con- taining

Sridhar Komarneni; DELLA M. ROY

1980-01-01

73

34. INVESTIGATIONS OF TERTIARY CLAY MINERAL DISTRIBUTIONS AROUND TASMANIA, DSDP, LEG 29  

Microsoft Academic Search

Clay minerals from Tertiary samples of DSDP Sites 280, 281, 282, and 283 were analyzed mainly by X-ray diffraction and cation ex- change methods. Site 282, off the Tasmanian west coast, contains a persistent Australian clay mineral assemblage that reflects deep weathering conditions in Tasmania and basic volcanism increasing from Eocene into the Oligocene. Site 280, south of the South

Victor A. Gostin; Kevin C. Moriarty

74

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

E-print Network

., 2001), and the continental record in the Middle East (Bar-Matthews et al., 1999; Felis et al., 2004Clay 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

Siebel, Wolfgang

75

Cation exchange dynamics confined in a synthetic clay mineral  

NASA Astrophysics Data System (ADS)

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.

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

76

Uranium deposits of The Grants, New Mexico mineral belt. [Geology, geochronology, clay mineralogy, trace element analysis  

Microsoft Academic Search

The Grants mineral belt forms a SE-trending linear belt of U deposits at the southern margin of the San Juan basin. The following geologic studies of the belt were made: stratigraphy, structures, tectonic history, ore deposits and their mineralogy, authigenic minerals, detrital minerals, clay minerals, geochronology, etc. Trace element analyses were carried out, including the U content of rocks. 13

Brookins

1975-01-01

77

Origin of clay-mineral variation in Wisconsinan age sediments from the Lake Michigan basin  

SciTech Connect

Drift samples collected in Wisconsin and Michigan from exposures representative of the Wisconsinan stratigraphy of the Lake Michigan Lobe indicate that clay mineral and shale lithology systematically vary between successive till sheets as a result of differential erosion of two unique source beds: shale bedrock, rich in 10[angstrom] clay (illite) and pre-existing drift (particularly lacustrine clay), depleted in 10[angstrom] clay. A general increase in relative amounts of 10[angstrom] clay and shale clasts begins with early or middle Wisconsinan (Altonian) Glenn Shores till and continues through late Wisconsinan (Woodfordian) Ganges-New Berlin till and Saugatuck-Oak Creek till. Both 10[angstrom] clay and shale decrease in post Mackinaw (late Woodfordian) Interstade Ozaukee-Haven and Two Rivers tills. Clay minerals in till rich in 10[angstrom] clay (Saugatuck-Oak Creek) were derived mainly from extensive erosion and comminution of shale whereas those in tills depleted in 10[angstrom] clay (Ganges-New Berlin, Ozaukee-Haven, and Two Rivers) were eroded mainly from lacustrine clay. Because it is compositionally dissimilar to either the shale or lake clay source and relatively rich in kaolinite, clay minerals in early-middle Wisconsinan Glenn Shores till may have been derived from Sangamon saprolite eroded during an early post-Sangamon ice advance. Variations in source bed erosion and subsequent changes in till lithology result either from depletion of the source bed (Glenn Shores till) or from progressively eroding drift mantling shale outcrops (unroofing) during successive late Wisconsinan ice advances.

Monaghan, G.W. (Geocomp Research, Eaton, NY (United States)); Larson, G.J. (Michigan State Univ., East Lansing, MI (United States). Dept. of Geological Sciences)

1994-04-01

78

Clay Minerals in Mawrth Vallis Region of Mars  

NASA Technical Reports Server (NTRS)

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.

2008-01-01

79

A general evaluation of the frequency distribution of clay and associated minerals in the alluvial soils of ceylon  

USGS Publications Warehouse

Clay mineral analyses were made of several alluvial clay materials from Ceylon. These studies show that the soil materials can be divided into 3 clay mineral provinces on the basis of the frequency distribution of clay and associated minerals. The provinces closely follow the climatic divisions. The characteristic feature of this classification is the progressive development of gibbsite from Dry to Wet Zone areas. Gibbsite has been used as a reliable indicator mineral. ?? 1971.

Herath, J. W.; Grimshaw, R. W.

1971-01-01

80

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

ERIC Educational Resources Information Center

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)

Kohut, Connie K.; And Others

1993-01-01

81

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

82

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

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

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

2012-06-01

83

Palaeozoic clay mineral sedimentation and diagenesis in the Dinant and Avesnes Basins (Belgium, France): relationships with Variscan tectonism  

NASA Astrophysics Data System (ADS)

Clay mineral investigations have been performed on more than 500 limestones and shales sampled in Lower Devonian (Emsian) to Lower Carboniferous (Namurian) outcrops in the Dinant and Avesnes Basins (Ardenne Massif, NW Europe). Clay mineral data have been placed in the palaeoenvironmental and structural histories documented by previous lithological, stratigraphical, palaeontological, diagenetic and tectonic contexts. The clay associations are dominated by illite and chlorite derived partly from the erosion of land masses surrounding the marine domain. The geothermal gradient estimated from correlation with conodont colour alteration index ranges between 40 and 70°C/km. A diachronous northwards migration of the diagenesis/metamorphism interface links to uplift caused by Late Carboniferous compressional folding and overthrusting. Associated clay minerals include smectite, locally preserved from diagenetic changes mainly by early pore closure, that reflect lagoonal or quiet offshore marine conditions. Smectite and subordinate kaolinite abundances decrease upwards during the Devonian in three successive intervals suggesting alternations of sub-arid to drier climates. The local occurrence of corrensite (ordered chlorite-smectite mixed-layer) is attributed to the moderate diagenetic transformation of pre-existing smectite

Han, G.; Preat, A.; Chamley, H.; Deconinck, J.-F.; Mansy, J.-L.

2000-11-01

84

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

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

85

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

NASA Astrophysics Data System (ADS)

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.

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

86

Transport and selective uptake of radium into natural clay minerals  

NASA Astrophysics Data System (ADS)

Understanding of the environmental behavior of Ra is important from the viewpoint of the long-termed repository safety of radioactive waste, but investigation of Ra behavior in natural environment is difficult to detect. We found isotopic evidence of Ra transportation and its selective uptake into clay minerals from Pb isotopic analyses. Illite grains found in calcite veins included in sandstone near the Oklo uranium deposit, Republic of Gabon, show extremely low 207Pb/ 206Pb (˜ 0.0158) isotopic ratios. Although the Pb isotopic ratios of calcite and quartz coexisting with illite indicate the formation age of each component, those of illite do not. In addition, illite grains having low 207Pb/ 206Pb isotopic ratios contain a strongly large amount of Ba (1230 to 6010 ppm) in contrast with low contents of Ba in calcite and quartz (< 0.26 ppm). Considering the chemical similarity between Ba and Ra, the 207Pb/ 206Pb isotopic data suggest an excess of 206Pb due to selective adsorption of 226Ra (and also Ba) into illite grains. This is a very rare example to show evidence of the selective adsorption behavior of Ra from the isotopic excesses of 206Pb, although the adsorption ability of Ra itself in nature was largely reported.

Hidaka, Hiroshi; Horie, Kenji; Gauthier-Lafaye, Françoise

2007-12-01

87

Correlation of the Abundance of Betaproteobacteria on Mineral Surfaces with Mineral Weathering in Forest Soils  

PubMed Central

Pyrosequencing-based analysis of 16S rRNA gene sequences revealed a significant correlation between apatite dissolution and the abundance of betaproteobacteria on apatite surfaces, suggesting a role for the bacteria belonging to this phylum in mineral weathering. Notably, the cultivation-dependent approach demonstrated that the most efficient mineral-weathering bacteria belonged to the betaproteobacterial genus Burhkolderia. PMID:22798365

Lepleux, C.; Turpault, M. P.; Oger, P.; Frey-Klett, P.

2012-01-01

88

Lithium, a preliminary survey of its mineral occurrence in flint clay and related rock types in the United States  

USGS Publications Warehouse

Maximum concentrations of lithium found in samples of flint clay and associated rocks of Pennsylvanian age in different States, in parts per million (ppm), are: Missouri, 5100; Pennsylvania-Maryland, 2100; Kentucky, 890; Ohio, 660; Alabama, 750; and Illinois, 160. Lithium-bearing kaolin deposits are distributed in the Coastal Plain province from New Jersey to Texas, and one occurs in Idaho; maximum lithium concentrations in samples from these deposits range from 64 to 180 ppm. The maximum concentration found in the Arkansas bauxite region is 460 ppm and that in flint clay in Colorado is 370 ppm. Samples from areas other than Pennsylvania, Maryland, Kentucky and Missouri are relatively few in number, represent mostly commercially valuable clays, and represent only a part of the refractory clay deposits in the United States. Data are not available on the clays associated with these deposits that may be unusable because they contain too much lithium as well as other deleterious elements. In both Pennsylvania and Missouri, lithium contents vary regionally between districts and locally between deposits. In samples containing more than 2000 ppm lithium, the lithium occurs in a dioctahedral chlorite mineral very similar to cookeite, which previously has not been recognized in sedimentary clays. The associated clays consist chiefly of well-crystallized kaolinite. The dioctahedral chlorite, however, seems to be most abundant where diaspore and boehmite occur along with the kaolinite. Barium, chromium, copper, phosphorus and strontium are present in some samples in amounts of several hundred pans per million or more, and may contribute to the failure of some clays to perform satisfactorily in firing tests. Lithium-rich clays could serve as a significant lithium resource in the very distant future. Clays that contain as much as 1% lithium may be common enough in Missouri or in Pennsylvania to be produced as a by-product to help support benefication costs for refractory clays. Sufficient amounts of lithium-rich clay may be found in deposits that have been explored, found unsatisfactory for normal refractory uses, and not developed. The lithium-rich clay in some deposits presently being worked may be worth stockpiling for eventual use. ?? 1978.

Tourtelot, H.A.; Brenner-Tourtelot, E. F.

1978-01-01

89

Determination of the composition of the organic matter chemically stabilized by agricultural soil clay minerals: Spectroscopy and Density Fractionation  

NASA Astrophysics Data System (ADS)

The interactions between soil organic matter and clay minerals are considered important processes because of their ability to sequester C in soil for long periods of time, and hence control C in the global C cycle when present. However, differing results have been reported regarding the composition of the soil organic matter - aromatic fractions versus aliphatic fractions - associated with clay minerals. To clarify this critical issue and better understand the C sequestration process in soils, we aimed to determine the nature of the chemically bound natural organic matter on clay surfaces, and to probe the speciation and spatial distribution of C in the soil clay nanoparticles using direct spectroscopic measurements namely solid-state CP-MAS and DP-MAS 13C NMR spectroscopy, x-ray diffraction spectroscopy (XRD), and scanning transmission x-ray microscopy (STXM). We tested the hypotheses that peptides and polysaccharides are stabilized by the smectite-illite clay while the lipids and black carbon are a separate phase; and that they are evenly distributed on clay surfaces. A soil clay fraction (5.5% organic C) was isolated from the surface of a prairie soil (Mollisol) in southwestern Minnesota, characterized by a pH 6.0, 32.5% clay content, and 3.7% organic carbon, using a sonication-sedimentation-siphoning process in distilled water. Then was subjected to density separation combined with low energy ultrasonic dispersion to separate the free organic and black C (light fraction) from the chemically bound C (heavy fraction). The XRD results indicated a dominance of interstratified smectite-illite clays in soil. The 13C-NMR spectra of the soil clay fraction suggested that polysaccharides and polypeptides are the prevailing components of the organic matter associated with the mineral clay, with only a minor component of aromatic C. The light fraction has strong alkyl C-H bands characteristic of fatty acids plus strong C-O bands characteristic of polysaccharides, including the anomeric C band centered at 105 ppm. The aromatic band at 130 ppm and the phenolic C-O band at 150 pm are strong as well indicating the presence of black carbon and lignin-derived components, contrary to the heavy fraction where they are almost absent. STXM results indicated that the proteins are abundant in the soil clay fraction, separate from lipids, and partially associated with saccharides. The black carbon constitutes a separate phase, but is amply present with lipids and lignin-derived compounds in the light fraction. We conclude that (1) the smectite-illite sheets in our soils preferentially retain peptides, and polysaccharides favoring the protection of these normally readily biodegradable fractions relative to the lignin-derived phenolic components; (2) the black carbon constitutes a major component of the light fraction, and is partially attached to the organic matter bonded with the smectitic clays; and (3) the lipids are associated with soil clay fraction as a separate phase, but are not bound to clay minerals.

Oufqir, Sofia; Bloom, Paul; Toner, Brandy; Hatcher, Patrick

2014-05-01

90

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 coring at three key locations along the San Andreas Fault Observatory at depth (SAFOD) drill hole of the dominant authigenic clay species across the San Andreas Fault zone (sampled at 3,066 and 3,436 m measured

91

Subsurface water and clay mineral formation during the early history of Mars  

Microsoft Academic Search

Clay minerals, recently discovered to be widespread in Mars's Noachian terrains, indicate long-duration interaction between water and rock over 3.7 billion years ago. Analysis of how they formed should indicate what environmental conditions prevailed on early Mars. If clays formed near the surface by weathering, as is common on Earth, their presence would indicate past surface conditions warmer and wetter

Bethany L. Ehlmann; John F. Mustard; Scott L. Murchie; Jean-Pierre Bibring; Alain Meunier; Abigail A. Fraeman; Yves Langevin

2011-01-01

92

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

E-print Network

AREAL DISTRIBUTION OF CLAY MINERALS AND THEIR RELATIONSHIP TO PHYSICAL PROPERTIES, GULF OF HEXICO A Thesis by WILLIAM E: HOTTMAN Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December 1975 Major Subject: Oceanography AREAL DISTRIBUTION OF CLAY MINERALS AND THEIR RELATIONSHIP TO PHYSICAL PROPERTIES, GULF OF MEXICO A Thesis by WILLIAM E. HOTTMAN Approved as to style and content by: Chairman...

Hottman, William Edward

2012-06-07

93

Clay Minerals as Solid Acids and Their Catalytic Properties.  

ERIC Educational Resources Information Center

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)

Helsen, J.

1982-01-01

94

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

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.

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

1997-05-01

95

The Efficiency of 24 Minerals as Deposition Ice Nuclei: Focus on Feldspars, Clays and Metals  

NASA Astrophysics Data System (ADS)

While the ice nucleating abilities of clay minerals have been extensively studied, those of the more minor mineralogical components of mineral dust have not been as widely examined. As a result, the deposition ice nucleating abilities of 24 atmospherically-relevant mineral samples were investigated using the University of Toronto continuous flow diffusion chamber at -40.0 × 0.3oC, using the same particle size (200nm) and preparation procedure throughout. The pure minerals' ice nucleating efficiencies were compared to those of complex mixtures (Arizona Test Dust and Mojave Desert Dust) and to that of lead iodide, which in the past was a prospective cloud seeding agent. Requiring a relative humidity with respect to ice (RHi) of 122.0 × 2.0% to activate 0.1% of the particles, lead iodide was the most efficient ice nucleus (IN) considered. Mojave Desert Dust (RHi 126.3 × 3.4%) and Arizona Test Dust (RHi 129.5 × 5.1%) exhibited lower but comparable activities. Through the analysis of a series of clay minerals (kaolinite, illite, montmorillonite), non-clay minerals (e.g. hematite, magnetite, calcite, cerussite, quartz, and other metal-containing species), and feldspar minerals (orthoclase, plagioclase) it was found that the feldspar minerals (particularly orthoclase), and not the clays, were the most efficient ice nuclei. Orthoclase and plagioclase were found to have critical RHi values of 127.1 × 6.3% and 136.2 × 1.3%, respectively. The presence of feldspars (most notably orthoclase) may play a large role in the deposition IN efficiencies of mineral dusts in spite of their lower percentage in composition relative to clay minerals. By contrast, most metal oxides, sulfide and sulfates were poor ice nuclei.

Yakobi-Hancock, J.; Ladino Moreno, L.; Abbatt, J.

2013-12-01

96

[Analysis of XRD spectral characteristics of soil clay mineral in two typical cultivated soils].  

PubMed

The present paper took black soil and chernozem, the typical cultivated soil in major grain producing area of Northeast, as the study object, and determinated the soil particle composition characteristics of two cultivated soils under the same climate and location. Then XRD was used to study the composition and difference of clay mineral in two kinds of soil and the evolutionary mechanism was explored. The results showed that the two kinds of soil particles were composed mainly of the sand, followed by clay and silt. When the particle accumulation rate reached 50%, the central particle size was in the 15-130 microm interval. Except for black soil profile of Shengli Xiang, the content of clay showed converse sequence to the central particle in two soils. Clay accumulated under upper layer (18.82%) in black soil profile while under caliche layer (17.41%) in chernozem profile. Clay content was the least in parent material horizon except in black profile of Quanyanling. Analysis of clay XRD atlas showed that the difference lied in not only the strength of diffraction peak, but also in the mineral composition. The main contents of black soil and chernozem were both 2 : 1 clay, the composition of black soil was smectite/illite mixed layer-illite-vermiculite and that of chernozem was S/I mixture-illite-montmorillonite, and both of them contained little kaolinite, chlorite, quartz and other primary mineral. This paper used XRD to determine the characteristics of clay minerals comprehensively, and analyzed two kinds of typical cultivated soil comparatively, and it was a new perspective of soil minerals study. PMID:25269317

Zhang, Zhi-Dan; Luo, Xiang-Li; Jiang, Hai-Chao; Li, Qiao; Shen, Cong-Ying; Liu, Hang; Zhou, Ya-Juan; Zhao, Lan-Po; Wang, Ji-Hong

2014-07-01

97

Effect of treatment with acids on the state of the surface of natural clay minerals  

Microsoft Academic Search

The state of the surface of natural clay minerals containing montmorillonite (lamellar structure), clinoptilolite (rigid skeleton\\u000a structure), and palygorskite (lamellar-banded structure) and of the same minerals modified with a 17% solution of sulfuric\\u000a acid was examined. It was established that the modification affected the specific surface area and porosity of the minerals\\u000a studied. It was found that the degree of

L. A. Novikova; L. I. Bel’chinskaya; F. Roessner

2006-01-01

98

Clay-mineral suites, sources, and inferred dispersal routes: Southern California continental shelf  

USGS Publications Warehouse

Clay mineralogy is useful in determining the distribution, sources, and dispersal routes of fine-grained sediments. In addition, clay minerals, especially smectite, may control the degree to which contaminants are adsorbed by the sediment. We analyzed 250 shelf sediment samples, 24 river-suspended-sediment samples, and 12 river-bed samples for clay-mineral contents in the Southern California Borderland from Point Conception to the Mexico border. In addition, six samples were analyzed from the Palos Verdes Headland in order to characterize the clay minerals contributed to the offshore from that point source. The <2 ??m-size fraction was isolated, Mg-saturated, and glycolated before analysis by X-ray diffraction. Semi-quantitative percentages of smectite, illite, and kaolinite plus chlorite were calculated using peak areas and standard weighting factors. Most fine-grained sediment is supplied to the shelf by rivers during major winter storms, especially during El Nin??o years. The largest sediment fluxes to the region are from the Santa Ynez and Santa Clara Rivers, which drain the Transverse Ranges. The mean clay-mineral suite for the entire shelf sediment data set (26% smectite, 50% illite, 24% kaolinite+chlorite) is closely comparable to that for the mean of all the rivers (31% smectite, 49% illite, 20% kaolinite+chlorite), indicating that the main source of shelf fine-grained sediments is the adjacent rivers. However, regional variations do exist and the shelf is divided into four provinces with characteristic clay-mineral suites. The means of the clay-mineral suites of the two southernmost provinces are within analytical error of the mineral suites of adjacent rivers. The next province to the north includes Santa Monica Bay and has a suite of clay minerals derived from mixing of fine-grained sediments from several sources, both from the north and south. The northernmost province clay-mineral suite matches moderately well that of the adjacent rivers, but does indicate some mixing from sources in adjacent provinces.

Hein, J.R.; Dowling, J.S.; Schuetze, A.; Lee, H.J.

2003-01-01

99

Clay-mineral assemblages from late Quaternary deposits on Vancouver Island, southwestern British Columbia, Canada  

NASA Astrophysics Data System (ADS)

On Vancouver Island, the Dashwood Drift, Cowichan Head Formation, Quadra Sand, and Vashon Drift were deposited during late Pleistocene glacial and interstadial periods and show large variations in clay-mineral contents partly related to changing climatic conditions. Glacial deposits are characterized by iron-rich chlorite, illite (both well crystallized), and smectite with a morphology reflecting rapid derivation from volcanic rocks. The clay mineralogy of nonglacial deposits is more complex, and is marked by the presence of vermiculite, kaolinite, halloysite, and irregular mixed-layer minerals. Nonglacial clay minerals are poorly preserved and show a higher state of alteration due to pedogenesis. Large variations in nonglacial deposits compared to glacial deposits are also due to secondary factors such as selective sorting, soil and rock source variations, differences in sedimentary environment, and diagenesis. These secondary factors do not seem to obliterate significantly the climatic imprint on the clay minerals. These studies also permit the recognition of glacially reworked sediments, the determination of relationships between two units in the same section, and the establishment of the conditions of clay-mineral formation.

Blaise, Bertrand

1989-01-01

100

Potassium Fixation and Supply by Soils with Mixed Clay Minerals.  

E-print Network

clay. If the sequence of weathering on these soils is Illite+Montmorillonite, these data suggest that the use of fixed K by plants proceeds at a faster rate than the decrease in K fixing capacity brought about by the weather- ing process. TABLE 2... clay. If the sequence of weathering on these soils is Illite+Montmorillonite, these data suggest that the use of fixed K by plants proceeds at a faster rate than the decrease in K fixing capacity brought about by the weather- ing process. TABLE 2...

Hipp, Billy W.

1969-01-01

101

Review Article Clay and non-clay minerals in the pharmaceutical and cosmetic industries  

E-print Network

. Such minerals may be administered either orally as antacids, gastrointestinal protectors, antidiarrhoeaics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 3.1.1. Antacids

Ahmad, Sajjad

102

Clay minerals as a factor influencing the biochemical activity of soil microorganisms  

Microsoft Academic Search

The results of the study confirm the significance of clay minerals as a factor influencing the biochemical activity of soil\\u000a microorganisms. The soil microflora is influenced both by the direct effect of clays on the microbial cells and indirectly,\\u000a by their effect on the environment. The direct effect is projected into fundamental processes of the cycle of biogenic elements,\\u000a including

Z. Filip

1973-01-01

103

Michaelis constant ( K m ) of acid phospatase as affected by montmorillonite, illite, and kaolinite clay minerals  

Microsoft Academic Search

The influence of Ca homoionic clay minerals (montmorillonite, illite, and kaolinite) on the activity,Km, andVm values of acid phosphatase was examined in model experiments. At each substrate (p-nitrophenyl phosphate) level tested, the addition of increasing amounts of clays (50, 100, and 150 mg, respectively) decreased the activity and increased theKm value from 1.43×10?3m PNP (in the soluble state) to 82.3×10?3M

H. E. Makboul; J. C. G. Ottow

1979-01-01

104

Molecular dynamics simulations of water, solution, and clay mineral-water systems (Invited)  

NASA Astrophysics Data System (ADS)

Clays and clay minerals together with zeolites are major mineral components in the earth's surface environment. These minerals interact with the atmosphere, natural water, inorganic and organic components in soils, etc. Physicochemical processes in the surface region are generally complex and difficult to understand because of the complicated "molecular" structures and the ambient conditions under wet circumstances. We have investigated the structure and physical/dynamical properties of the mineral-gas/liquid systems by means of molecular simulation methods; molecular dynamics and Metropolis Monte Carlo methods. Swelling of smectite and adsorption of inorganic molecules in clay minerals and zeolites, etc. were simulated and analyzed on the basis of the atomic and molecular processes. We have developed atomic and molecular interaction models of inorganic systems. The models compose of electrostatic, short range repulsive, van der Waals and covalent (radial and angular) terms with respect to all the elements appeared in the mineral-water systems. All of our molecular dynamics simulations (MD) were performed with full degree of freedom of atom motions. Using the model for H2O molecule, the structure and physical properties such as density, diffusion coefficients, etc. of ice polymorphs and water are well reproduced. Alkaliharide aqueous solutions and gas hydrates and their (hydrophobic) solutions are also reasonably simulated. Clay mineral-water interactions are particularly important to understand the mechanical and chemical processes in the environments, in order to develop nano-composite materials, and to use clays in engineering applications. Absorption and swelling are the most remarkable properties of clay minerals, specially smectite. We have investigate these properties by means of molecular simulation methods using various clay minerals-water/solution systems. The swelling curves, the relation between humidity and the basal spacings, were reproduced quantitatively, and nano-scopic structural and dynamic properties of interlayer aqueous solutions were obtained. Wetting of clay mineral surfaces determines the mechanical properties of clays, soils and sedimentary rocks. We investigated the wetting properties of smectite, kaolinite, pyrophyllite, brucite, etc. The wetness of these minerals is quite different with each other. The reson of these difference was demonstrated by our molecular simulations. One of our main purpose of studying clay nano-properties ais to know the fundamental nano-mechanical characteristics of clays, and to apply these properties to predict long term behavior of clay-based materials, such as engineering barriers for radioactive waste disposal. For this purpose, unified nano-micro-macro mechanical approaches should be established (Ichikawa, et al. (1999)“Unified molecular dynamics and homogenization analysis for bentonite behavior: Current results and future possibilities. Engineering Geology, 54, 21-31. Choi, et al. (2008) Transport phenomena in kaolinite clay: Molecular simulation, homogenization analysis. Int.J.Numer. Analy. Meth. Geomech., DOI:10.1002/nag.744.)

Kawamura, K.

2009-12-01

105

ATTENUATION OF POLLUTANTS IN MUNICIPAL LANDFILL LEACHATE BY CLAY MINERALS  

EPA Science Inventory

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 st...

106

Alkali Cation Selectivity and Fixation by Clay Minerals  

Microsoft Academic Search

Two variables must be considered when calculating exchange free energies (AG~ for 2:1 clays: (1) anionic field strength, as expressed by equivalent anionic radius (ra), and (2) interlayer water content, as expressed by interlayer molality. For smectites that are in a state of high hydration, interlayer molality is determined by the cations undergoing exchange. Thus AG~ for an exchanging cation

Dennis D. Eberl

1980-01-01

107

The aggregation of clay minerals and marine microalgal cells : physicochemical theory and implications for controlling harmful algal blooms  

E-print Network

In recent years, the use of clay minerals has emerged as one of the most promising strategies for directly controlling harmful algal blooms (HABs). Its principle is based on the mutual aggregation of algal cells and mineral ...

Sengco, Mario Rhuel

2001-01-01

108

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

The MS-Q Force Field for Clay Minerals: Application to Oil Production Sungu Hwang, Mario Blanco of water, hydrocarbons, and polar organic compounds such as oil field production chemicals on clay mineral and corrosion inhibition). Among the minerals present in the walls of oil reservoirs, clay minerals are believed

Ã?agin, Tahir

109

Influence of the physicochemical properties of clay minerals on the degree of darkening via polycondensation reactions between catechol and glycine  

Microsoft Academic Search

Polycondensation reactions between amino acids and phenols are an important pathway for humification, and clay minerals are able to catalyze these reactions. In the present study, we investigated the influence of the physicochemical properties of some clay minerals on polycondensation reactions between catechol (CT) and glycine (Gly). The polycondensation of CT and Gly was evaluated using the specific absorbance at

Akitaka Miura; Ryo Okabe; Kenji Izumo; Masami Fukushima

2009-01-01

110

Chemistry and mineralogy of clay minerals in Asian and Saharan dusts and the implications for iron availability  

NASA Astrophysics Data System (ADS)

Mineral dust supplied to remote ocean regions stimulates phytoplankton growth through delivery of micronutrients, notably iron (Fe). Although attention is usually paid to Fe (hydr)oxides as major sources of available Fe, Fe-bearing clay minerals are typically the dominant phase in mineral dust. The mineralogy and chemistry of clay minerals in dust particles, however, are largely unknown. We conducted microscopic identification and chemical analysis of the clay minerals in Asian and Saharan dust particles. Cross-sectional slices of dust particles were prepared by focused ion beam (FIB) techniques and analyzed by transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDXS). TEM images of FIB slices revealed that clay minerals occurred as either nano-thin platelets or relatively thick plates. The nano-thin platelets included illite, smectite, illite-smectite mixed layers and their nanoscale mixtures (illite-smectite series clay minerals, ISCMs) which could not be resolved with an electron microbeam. EDXS chemical analysis of the clay mineral grains revealed that the average Fe content was 5.8% in nano-thin ISCM platelets assuming 14% H2O, while the Fe content of illite and chlorite was 2.8 and 14.8%, respectively. In addition, TEM and EDXS analyses were performed on clay mineral grains dispersed and loaded on microgrids. The average Fe content of clay mineral grains was 6.7 and 5.4% in Asian and Saharan dusts, respectively. A comparative X-ray diffraction analysis of bulk dusts showed that Saharan dust was more enriched in clay minerals than in Asian dust, while Asian dust was more enriched in chlorite. The average Fe / Si, Al / Si and Fe / Al molar ratios of the clay minerals, compared to previously reported chemistries of mineral dusts and leached solutions, indicated that dissolved Fe originated from clay minerals. Clay minerals, in particular nanocrystalline ISCMs and Fe-rich chlorite are important sources of available Fe in remote marine ecosystems. Further detailed analyses of the mineralogy and chemistry of clay minerals in global aerosols are required to determine the inputs of Fe available to surface ocean microbial communities.

Jeong, G. Y.; Achterberg, E. P.

2014-06-01

111

Diagenesis of clay minerals from early Eocene shales of Texas  

E-print Network

was rela- tively slow, with sequences reaching thicknesses of only 300 to 450 meters (Fisher and McGowen, 1969). Sediment for these systems was derived from the delta system, chiefly during periods of delta destruc- tion. Delta sediments were supplied... were prepared by packing samples in aluminum holders against filter paper. The coarse and fine clay size fractions were saturated with K or Ng by washing with either 1N KC1 or NgC1 solutions. Ng saturated samples were solvated with 10' glycerol...

Whynot, John David

2012-06-07

112

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

NASA Astrophysics Data System (ADS)

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.

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

1993-09-01

113

Investigating the behaviour of Mg isotopes during the formation of clay minerals  

NASA Astrophysics Data System (ADS)

We present elemental and isotopic data detailing how the Mg isotope system behaves in natural and experimentally synthesized clay minerals. We show that the bulk Mg isotopic composition (?26Mg) of a set of natural illite, montmorillonite and kaolinite spans a 2‰ range, and that their isotopic composition depends strongly on a balance between the relative proportions of structural and exchangeable Mg. After acid leaching, these natural clays become relatively enriched in isotopically heavy Mg by between 0.2‰ and 1.6‰. Results of exchange experiments indicate that the Mg that has adsorbed to interlayer spaces and surface charged sites is relatively enriched in isotopically light Mg compared to the residual clay. The isotopic composition of this exchangeable Mg (-1.49‰ to -2.03‰) is characteristic of the isotopic composition of Mg found in many natural waters. Further experiments with an isotopically characterized MgCl2 solution shows that the clay minerals adsorb this exchangeable Mg with little or no isotopic fractionation, although we cannot discount the possibility that the uptake of exchangeable Mg does so with a slight preference for 24Mg. To characterize the behaviour of Mg isotopes during clay mineral formation we synthesized brucite (Mg(OH)2), which we consider to be a good analogue for the incorporation of Mg into the octahedral sheet of Mg-rich clay minerals or into the brucitic layer of clays such as chlorite. In our experiment the brucite mineral becomes enriched in the heavy isotopes of Mg while the corresponding solution is always relatively enriched in isotopically light Mg. The system reaches a steady state after 10 days with a final fractionation factor (?solid-solution) of 1.0005 at near-neutral pH. This result is consistent with the general consensus that secondary clay minerals preferentially take up isotopically heavy Mg during their formation. However our results also show that exchangeable Mg is an important component within bulk clay minerals and can have an important influence over the bulk clay ?26Mg value. Modeling shows that in certain soils or sediments where the percentage of exchangeable Mg is >30% and the isotopic composition of the exchangeable Mg is around -2‰, the generation of bulk ?26Mg values of <-0.5‰ is likely. On a broader scale, Mg-rich minerals such as smectite and illite are likely to impart a stronger control over the Mg budget in clay rich sediments, and their high structural Mg component is likely to result in bulk sediment ?26Mg values that are closer in composition to the UCC. Despite this, results of modeling, together with experimental observation suggests that the uptake of exchangeable Mg into these clay rich sediments could cause a decrease in the bulk ?26Mg value by up to ˜0.3-0.4‰. This should be accounted for when assessing the ?26Mg value of sediments on a crustal scale.

Wimpenny, Joshua; Colla, Christopher A.; Yin, Qing-Zhu; Rustad, James R.; Casey, William H.

2014-03-01

114

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

115

Clay and non-clay minerals in the pharmaceutical industry Part I. Excipients and medical applications  

E-print Network

) immobilization of limbs and fractures or dental and craniofacial surgical procedures in traumatology, d) bone grafts or construction of orbital implants, and e) spas and aesthetic centers. Examples of such minerals

Ahmad, Sajjad

116

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

E-print Network

The purpose of this study was to implement a new, rapid field method to effectively and accurately detect harmful clay minerals in aggregate fines by using the modified methylene blue (MMB) test. The focus of this study was based on existing...

Pitre, Brandon

2012-12-04

117

Mechanochemical polymerization of styrene initiated by the grinding of layered clay minerals  

Microsoft Academic Search

The polymerization of styrene mechanochemically initiated by the grinding of talc was performed by using a vibrating ball mill. Talc used was one of layered clay minerals as well as montmorillonite. The effect of the grinding of talc on the polymerization of the styrene was investigated by characterizing the polymer formed and talc ground. The results revealed that of all

Masahiro Hasegawa; Mitsumasa Kimata; Itsuo Takahashi

2007-01-01

118

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

E-print Network

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

Sparks, Donald L.

119

Structural Transformation of Clay Minerals by a New Molecular Dynamics Simulation Method  

Microsoft Academic Search

A MD simulation study of 2:1 clay minerals is carried out using a new MD simulation method which is capable of simulating a system under the most general external stress conditions by considering the changes of MD cell size and shape. The tensor defining the cell size and shape is correlated with the atomic level stress tensors (both internal and

Jianfeng Wang; Marte Gutierrez

2010-01-01

120

Catalytic activity of hammerhead ribozymes in a clay mineral environment: implications for the RNA world.  

PubMed

The hypothesized RNA-based world would have required the presence of a protected environment in which RNA, or an RNA-like molecule, could originate and express its biological activity. Recent studies have indicated that RNA molecules adsorbed/bound on clay minerals are able to persist in the presence of degrading agents, to interact with surrounding molecules, and to transmit the information contained in their nucleotide sequences. In this study, we assessed the ability of RNA molecules with catalytic activity to perform a specific reaction in a mineral environment. For this purpose, we investigated the self-cleavage reaction of the hammerhead ribozyme of the Avocado Sun Blotch Viroid (ASBVd), both in the monomeric and in dimeric forms. The monomeric transcript was tightly bound on the clay mineral montmorillonite to form a stable complex, while the behaviour of the dimeric transcript was studied in the presence of the clay particles in the reaction mixture. The results indicated that the hammerhead ribozyme was still active when the monomeric transcript was adsorbed on the clay surface, even though its efficiency was reduced to about 20% of that in solution. Moreover, the self-cleavage of clay-adsorbed molecule was significantly enhanced ( approximately four times) by the presence of the 5' reaction product. The self-cleavage reaction of the dimeric transcript in the presence of montmorillonite indicated that the mineral particles protected the RNA molecules against aspecific degradation and increased the rate of cleavage kinetics by about one order of magnitude. These findings corroborate the hypothesis that clay-rich environments would have been a good habitat in which RNA or RNA-like molecules could originate, accumulate and undergo Darwinian evolutionary processes, leading to the first living cells on Earth. PMID:17125938

Biondi, Elisa; Branciamore, Sergio; Fusi, Luca; Gago, Selma; Gallori, Enzo

2007-03-01

121

Carbon Sequestration by Smectite Clay Minerals in Soils  

Microsoft Academic Search

Molecular simulations can be used to explore fundamental interactions that govern the formation of organo-mineral complexes in soils, complexes that in turn control the size and turnover of soil carbon pools. A suitable model organic molecule, featuring properties and behavior typical of the recalcitrant portion of soil carbon in humic substances, is needed for these simulations. The latest iteration of

Garrison Sposito; Rebecca Sutton

2006-01-01

122

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  

E-print Network

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 ...

Schumann, Dirk

123

Rapid Clay Mineral Formation in Amazon Delta Sediments: Reverse Weathering and Oceanic Elemental Cycles  

NASA Astrophysics Data System (ADS)

Formation of aluminosilicate minerals in marine sediments was proposed over 30 years ago as a potentially important control on the chemistry of the oceans. Until now, this reverse weathering process has been largely discounted because of insufficient direct evidence for its existence. Experiments with unaltered, anoxic, Amazon delta sediments showed that substantial quantities of K-Fe-Mg clay minerals precipitated on naturally occurring solid substrates over times of ~12 to 36 months at ~28^circC. A range of pore-water, solute-flux, and solid-phase criteria indicates that comparable clay mineral precipitation processes occur throughout Amazon shelf sediments, contributing gtrsim3 percent of the weight of the deposits and consuming ~10 percent of the global riverine K^+ flux.

Michalopoulos, Panagiotis; Aller, Robert C.

1995-10-01

124

Clay minerals in primitive meteorites and interplanetary dust 1  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

125

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

USGS Publications Warehouse

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.

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

2005-01-01

126

Clay mineral formation on Mars: Chemical constraints and possible contribution of basalt out-gassing  

NASA Astrophysics Data System (ADS)

We focus on processes possibly occurring on Mars that could affect sufficiently large volumes of rocks to be detected by remote sensing techniques. When compared with the chemical modelling of water-rock interactions, the petrographic and mineralogical characteristics of clay deposited in the prismatic joints of a lava flow from the Parana basin (Brazil) suggest that the clay fraction of lava flows may be formed at least partly during an early post-magmatic stage associated with the degassing of acid volatiles. In view of the literature concerning other contexts, such as meteorites or experimental syntheses, we conclude that the crystallization of anhydrous mafic minerals and the formation of clay mineral are not systematically mutually exclusive phenomena. While clay formation is generally related to chemical reaction pathways, it is not necessarily due to the alteration of pre-existing silicates. Such post-magmatic reactions, even if they are likely to represent only a minor contribution to Martian clay formation limited to early Noachian times, require much lower amounts of water compared to conventional hydrothermal alteration or weathering systems. The products of these reactions can be detected over large surface areas, as in the case of the Mars sites, thus allowing us to envisage a greater diversity of paleogeographic scenarios for Early Mars.

Berger, Gilles; Meunier, Alain; Beaufort, Daniel

2014-05-01

127

Atomistic simulations of clay minerals subject to variably hydrated supercritical CO2  

NASA Astrophysics Data System (ADS)

Commonly occurring clay minerals, such as phyllosilicates, tend to expand as they incorporate water. The ubiquitous presence and importance of clay minerals in caprock seals and shale gas plays undergoing enhanced gas recovery with CO2 requires much better understanding of chemically induced changes in these minerals upon contact with variably wet scCO2. Recent advances in our groups experimental techniques have enabled detailed characterization of the H2O/CO2 intercalation in a variety of montmorillonites. In parallel, we have also initiated density functional (DFT) simulations to help understand the interactions between layered materials and the water-bearing supercritical fluid alone or in the presence of sulfur-containing species, pertinent to mixed-gas injection conditions. Through our simulations, we expect to understand how CO2 interacts with different intra-layer ions under different degrees of hydration or the presence of sulfur-containing species, and how the overall swelling properties of the clays will be affected. Preliminary results indicate that clays with higher degrees of hydration are likely to expand more after CO2 intercalation, as illustrated in Figure 1.; Figure 1. Radial distribution function of Ca-C obtained from DFT-based molecular dynamics simulations of fully hydrated Ca2+ ions in supercritical CO2 show that the CO2 molecules will be found at average distances > 5 Å and can potentially induce higher degrees of swelling.

Glezakou, V.; Schaef, T.; McGrail, P.

2012-12-01

128

Formation of clay minerals and exhumation of lower-crustal rocks at Atlantis Massif, Mid-Atlantic Ridge  

NASA Astrophysics Data System (ADS)

Low-temperature alteration products in gabbros from the ocean floor have significant implications for incipient processes of seawater-rock interaction and exhumation tectonics of the lower-crustal rocks. In this paper we report mode of occurrence and mineralogical characteristics of clay minerals in gabbroic rocks recovered from Integrated Ocean Drilling Program (IODP) Hole U1309D at an oceanic core complex, Atlantis Massif, Mid-Atlantic Ridge at 30°N. The clay minerals were identified by optical microscope, electron microprobe, Raman spectrometer, and transmission electron microscope as mainly composed of mixed-layer saponite-talc, saponite, and vermiculite. They are characteristically rich in iron that is significantly oxidized and distributed into the tetrahedral site, suggesting a relatively high-temperature condition for oxidation. They are restricted to domains near the contacts between olivine and talc or form pseudomorphs after olivine near microcracks filled with zeolite or clay minerals. These facts suggest the infiltration of oxidative seawater and reactions to variable fluid/rock ratios at variable temperatures. Close association of vermiculite with microcracks radiated from serpentinized olivine suggests that the deep infiltration of seawater at an off-axis region was caused by fracturing resulting from serpentinization and enhanced by relatively abundant olivine-rich lithology at Atlantis Massif. Compared with gabbroic rocks of an oceanic core complex at ultraslow-spreading ridge (ODP Hole 735B), those of Atlantis Massif substantially lack mixed-layer smectite-chlorite. Mixed-layer smectite-chlorite is a product of prehnite-actinolite to greenschist facies alteration and looks to preserve a record of ambient thermal structure through which the massif passed on rising to a shallow level. The absence of pervasive formation of mixed-layer smectite-chlorite under relatively reducing conditions suggests low permeability and/or limited fluid-rock reactions on the way to shallow levels. From the observation and consideration of the characteristics of clay minerals, sequence and distribution of static alteration related to fracturing, original lithology, and tectonic settings of the oceanic core complexes, we conclude that Atlantis Massif was more rapidly exhumed to the oxidative subseafloor environment than Atlantis Bank. The difference of exhumation rate possibly reflected either the disparity in spreading rate between the whole ridge systems or regional variation of exhumation tectonics between the two oceanic core complexes.

Nozaka, Toshio; Fryer, Patricia; Andreani, Muriel

2008-11-01

129

Mineralization of clay/polymer aerogels: a bioinspired approach to composite reinforcement.  

PubMed

Clay aerogels, ultra low density materials made via a simple freeze-drying technique, have shown much promise in broad applications because of their low densities, often in the same range as silica aerogels (0.03-0.3 g/cm(3),) but suffering from low mechanical strength. A bioinspired approach to mineralize an active polymer/clay aerogel composite is inspected, showing marked improvement of the mechanical properties with increasing modification. Further property improvement was achieved using a layer-by-layer approach to produce alternate layers of polymer and silica on the surface. PMID:20355926

Johnson, Jack R; Spikowski, Jane; Schiraldi, David A

2009-06-01

130

Leaching of clay minerals in a limestone environment  

USGS Publications Warehouse

Water saturated with CO2 at about 25??C was percolated through mixed beds of limestone or marble fragments and montmorillonite, "illite" and kaolinite in polyethylene tubes for six and fortyfive complete runs. The leachates were analysed for SiO2, A12O3 and Fe2O3, but only SiO2 was found. The minerals lost SiO2 in this order: montmorillonite > kaolinite > "illite". The differential removal of SiO2 during the short period of these experiments suggests a mechanism for the accumulation of bauxite deposits associated with limestones. ?? 1959.

Carroll, D.; Starkey, H. C.

1959-01-01

131

Measurement of Cu and Zn adsorption onto surficial sediment components: new evidence for less importance of clay minerals.  

PubMed

Clay minerals in surficial sediment samples, collected from the Songhua River in China, were separated via sedimentation after removal of Fe/Mn oxides and organic materials; Cu and Zn adsorption onto the sediment components was then evaluated. Clay minerals were examined via X-ray diffraction and scanning electron microscopy. Clay minerals were found to consist mainly of illite, kaolinite, chlorite and an illite/smectite mixed layer. Non-clay minerals were dominated by quartz and orthoclase. The retention of Cu and Zn by clay minerals was 1.6 and 2.5 times, respectively, greater than that of the whole, untreated surficial sediment. Compared to the other critical components in sediments related to metal sorption (Mn oxides, Fe oxides and organic materials), the adsorption capacity of clay minerals was found to be relatively lower on a unit mass basis. These data suggest that, although clay minerals may be important in the adsorption of heavy metals to aquatic sediments, their role is less significant than Fe/Mn oxides and organic materials. PMID:21466918

Wang, Xiaoli; Li, Yu

2011-05-30

132

The interactions of humic compounds with electrolytes and three clay minerals under simulated estuarine conditions  

NASA Astrophysics Data System (ADS)

Laboratory studies of the reactions between dissolved humic substances and dissolved sodium, magnesium, calcium, iron and aluminium are described together with studies of the adsorption of humic substances onto the clay minerals illite, kaolinite and montmorillonite under simulated estuarine conditions. It is demonstrated that only minor quantities of humic substances are precipitated in the presence of Na, Mg and Ca up to ca. 1.5 times their seawater concentrations. The total amount of humic substance precipitated is dependent on the cation present and increases in the order Naclay minerals depend not only on the nature of the compounds or minerals but also on the salinity of the reaction medium. There is evidence that interactions with clay minerals can lead to fractionation of different humic components.

Preston, M. R.; Riley, J. P.

1982-05-01

133

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

134

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

PubMed

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 m(2) 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

Kennedy, Martin J; Wagner, Thomas

2011-06-14

135

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

PubMed Central

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

Kennedy, Martin J.; Wagner, Thomas

2011-01-01

136

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

NASA Technical Reports Server (NTRS)

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.

Burt, D. M.

1989-01-01

137

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

USGS Publications Warehouse

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.

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

1986-01-01

138

Clay-mineral assemblages from some levels of K-118 drill core of Maha Sarakham evaporites, northeastern Thailand  

NASA Astrophysics Data System (ADS)

Clay-mineral assemblages in Middle Clastic, Middle Salt, Lower Clastic, Potash Zone, and Lower Salt, totalling 13 samples from K-118 drill core, in the Maha Sarakham Formation, Khorat Basin, northeastern Thailand were studied. The clay-size particles were separated from the water-soluble salt by water leaching. Then the samples were leached again in the EDTA solution and separated into clay-size particles by using the timing sedimentation. The EDTA-clay residues were divided and analyzed by using the XRD and XRF method. The XRD peaks show that the major-clay minerals are chlorite, illite, and mixed-layer corrensite including traces of rectorite? and paragonite? The other clay-size particles are quartz and potassium feldspar. The XRF results indicate Mg-rich values and moderate Mg?Al atom ratio values in those clay minerals. The variable Fe, Na, and K contents in the clay-mineral assemblages can explain the environment of deposition compared to the positions of the samples from the core. Hypothetically, mineralogy and the chemistry of the residual assemblages strongly indicate that severe alteration and Mg-enrichment of normal clay detritus occurred in the evaporite environment through brine-sediment interaction. The various Mg-enrichment varies along the various members reflecting whether sedimentation is near or far from the hypersaline brine.

Suwanich, Parkorn

139

Subsurface water and clay mineral formation during the early history of Mars.  

PubMed

Clay minerals, recently discovered to be widespread in Mars's Noachian terrains, indicate long-duration interaction between water and rock over 3.7 billion years ago. Analysis of how they formed should indicate what environmental conditions prevailed on early Mars. If clays formed near the surface by weathering, as is common on Earth, their presence would indicate past surface conditions warmer and wetter than at present. However, available data instead indicate substantial Martian clay formation by hydrothermal groundwater circulation and a Noachian rock record dominated by evidence of subsurface waters. Cold, arid conditions with only transient surface water may have characterized Mars's surface for over 4 billion years, since the early-Noachian period, and the longest-duration aqueous, potentially habitable environments may have been in the subsurface. PMID:22051674

Ehlmann, Bethany L; Mustard, John F; Murchie, Scott L; Bibring, Jean-Pierre; Meunier, Alain; Fraeman, Abigail A; Langevin, Yves

2011-11-01

140

Clay mineral facies and lateritization in basalts of the southeastern Parana Basin, Brazil  

NASA Astrophysics Data System (ADS)

Seventeen samples from two lateritic profiles, each with five facies, were studied. These profiles occur on the old planation surface of the plateau basalts of the southern part of ParanáBasin, Brazil. Optical microscopy, X-ray diffraction, electron microprobe, Mössbauer spectroscopy and Fourier Transform Infrared Spectra were used to obtain information about the nature and chemical composition of each weathering facies. In addition, scanning electron microscopy and analyses of clay minerals were performed to detect microcrystalline environmental changes. Both profiles have two major parts: a loose red-clay latosol separated from an underlying mottled clay and an alterite facies; a stone line may or may not be present between the latosol and the underlying units. In both profiles the latosol consists principally of kaolinite, hematite and goethite. Two alterite facies, shaped by differential weathering, are also present in the lower profile: a halloysite-nontronite clayey matrix with a well developed fissure system occurs in the argillaceous alterite and a network of Al-goethite aggregates is typical of the highly porous cortex of the boulder alterite that is found in the stone line and below it. Gibbsite has crystallized in the large pores of porphyritic boulder alterite but is absent in the small pores of the subaphyric boulder alterite. Clay minerals observed in fissures include halloysite associated with goethite and manganese oxides. The basalt has hydrothermal green-clays (mixed layers and trioctahedral smectites) that formed between primary plagioclase, pyroxene and Ti-magnetite crystals while fresh corestones of the boulder alterite have cryptocrystalline iron-rich material. The study of these profiles shows one principal evolutionary trend for clay minerals. This trend is from smectite and mixed layers that form green clays in altered bedrock at the base of the profile to an intermediate association of nontronite and halloysite in the argillaceous alterite to kaolinite in the mottled clay facies at the top of the profile. There is also another trend; the presence of a cryptocrystalline material sequence in the weathering of the corestones. This study of two polycyclic profiles developed on basalts shows the presence of iron-rich laterites in the southern ParanáBasin which are closely similar to the laterites in the northern part of the ParanáBasin.

de Oliveira, M. T. G.; Formoso, M. L. L.; Trescases, J. J.; Meunier, A.

1998-07-01

141

Aqueous suspensions of natural swelling clay minerals. 1. Structure and electrostatic interactions.  

PubMed

In this article, we present a general overview of the organization of colloidal charged clay particles in aqueous suspension by studying different natural samples with different structural charges and charge locations. Small-angle X-ray scattering experiments (SAXS) are first used to derive swelling laws that demonstrate the almost perfect exfoliation of clay sheets in suspension. Using a simple approach based on geometrical constraints, we show that these swelling laws can be fully modeled on the basis of morphological parameters only. The validity of this approach was further extended to other clay data from the literature, in particular, synthetic Laponite. For all of the investigated samples, experimental osmotic pressures can be properly described by a Poisson-Boltzmann approach for ionic strength up to 10(-3) M, which reveals that these systems are dominated by repulsive electrostatic interactions. However, a detailed analysis of the Poisson-Boltzmann treatment shows differences in the repulsive potential strength that are not directly linked to the structural charge of the minerals but rather to the charge location in the structure for tetrahedrally charged clays (beidellite and nontronites) undergoing stronger electrostatic repulsions than octahedrally charged samples (montmorillonites, laponite). Only minerals subjected to the strongest electrostatic repulsions present a true isotropic to nematic phase transition in their phase diagrams. The influence of ionic repulsions on the local order of clay platelets was then analyzed through a detailed investigation of the structure factors of the various clay samples. It appears that stronger electrostatic repulsions improve the liquidlike positional local order. PMID:21476528

Paineau, Erwan; Bihannic, Isabelle; Baravian, Christophe; Philippe, Adrian-Marie; Davidson, Patrick; Levitz, Pierre; Funari, Sérgio S; Rochas, Cyrille; Michot, Laurent J

2011-05-01

142

Adsorption and photooxidation of pharmaceuticals and personal care products on clay minerals  

Microsoft Academic Search

The adsorption and photodegradation behavior of tetracycline (TC), chloramphenicol (CAP) and sulfamethoxazole (SMX) in clay\\u000a mineral dispersion was investigated in this work. Only TC showed significant adsorption to natural montmorillonite and rectorite,\\u000a whereas CAP and SMX adsorbed to natural montmorillonite, kaolinite and rectorite to a much lower extent. The adsorption equilibrium\\u000a constants (L\\/kg) of TC to natural montmorillonite were 332

Yanxiang LiuXujie; Xujie Lu; Feng Wu; Nansheng Deng

143

Oxyanion sorption and surface anion exchange by surfactant-modified clay minerals  

SciTech Connect

In this study the sorption of nitrate (NO{sub 2}{sup {minus}}) and chromate (CrO{sub 4}{sup 2{minus}}) from aqueous solution by surfactant-modified clay minerals was investigated. Both the sorption and desorption of oxyanions were found to follow a Langmuir sorption isotherm. In general, the sorption affinity is higher for chromate than for nitrate, reflecting that the interaction between the divalent anions and the surfactant bilayer is stronger than that between the monovalent anions and the surfactant bilayer. Surfactant-modified kaolinite has a higher sorption capacity for chromate. The sorption capacities for chromate and nitrate are equal for surfactant-modified illite while the sorption capacity for nitrate is higher for surfactant-modified smectite. Desorption by water revealed that chromate sorption was irreversible, while nitrate sorption was slightly reversible. In a mixed solution system, nitrate and chromate compete for the same sorption sites, resulting in a decrease in sorption capacity for each anion. Stoichiometric counterion desorption due to chromate and/or nitrate sorption further confirms that sorption of oxyanions by surfactant-modified clay minerals was due to surface anion exchange. The selectivity coefficients were higher for chromate to replace bromide than for nitrate to replace bromide for surfactant-modified kaolinite, but lower when surfactant-modified illite and smectite were the anion exchangers. The results indicate that surfactant-modified clay minerals are effective sorbents to remove anionic contaminants from water. However, the types of clay minerals should be correctly selected to maximize the contaminant removal efficiency.

Li, Z.

1999-10-01

144

Measuring the specific caesium sorption capacity of soils, sediments and clay minerals  

Microsoft Academic Search

Two methods to quantify the specific Cs sorption capacity of soils and sediments, which is generally believed to be associated with the Frayed Edge Sites (FES) of illitic clay minerals, are described in detail and are critically reviewed. The first method is a direct measurement of the FES capacity, while the second quantifies the combined parameter KDCs×[K+](=KC(K?Cs)×[FES]), i.e. the product

A. de Koning; A. V. Konoplev; R. N. J. Comans

2007-01-01

145

Synthesis of Smectite Clay Minerals: A Critical Review  

SciTech Connect

Smectites are one of the most important groups of phyllosilicates found in soils and sediments, and certainly one of the most difficult to study. New information about the formation mechanisms, impact of structural features on surface properties, and long-term stability of smectites can best be gained from the systematic study of single-phase specimens. In most instances, these specimens can only be obtained through synthesis under controlled conditions. Syntheses of smectites have been attempted (1) at ambient pressure and low-temperature (< 100 C), (2) under moderate hydrothermal conditions (100-1000 C, pressures to several kbars), (3) under extreme hydrothermal conditions (>1000 C or pressures> 10 kbars), and (4) in the presence of fluoride. Of these approaches, syntheses performed under moderate hydrothermal conditions are the most numerous and the most successful in terms of smectite yield and phase- purity. Using hydrothermal techniques, high phase-purity can be obtained for beidellites and several transition-metal smectites. However, synthesis of montmorillonite in high purity remains difficult. Starting materials for hydrothermal syntheses include gels, glasses, and other aluminosilicate minerals. The presence of Mg2+ seems to be essential for the formation of smectites, even for phases such as montmorillonite which contain low amounts of Mg. Highly crystalline smectites can be obtained when extreme temperatures or pressures are used, but other crystalline impurities are always present. Although the correlation between synthesis stability fields and thermodynamic stability fields is good in many instances, metastable phases are often formed. Few studies, however, include the additional experiments (approach from under- and over-saturation, reversal experiments) needed to ascertain the conditions for formation of thermodynamically stable phases. Thorough characterization of synthetic products by modern instrumental and molecular-scale techniques is also needed to better understand the processes leading to smectite formation.

Kloprogge, J T. (unknown); Komarneni, S (Pennsylvania State University); Amonette, James E. (BATTELLE (PACIFIC NW LAB))

1999-01-01

146

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

147

Regional trends in clay mineral fluxes to the Queensland margin and ties to middle Miocene global cooling  

Microsoft Academic Search

Three ODP sites located on the Marion Plateau, Northeast Australian margin, were investigated for clay mineral and bulk mineralogy changes through the early to middle Miocene. Kaolinite to smectite (K\\/S) ratios, as well as mass accumulation rates of clays, point to a marked decrease in accumulation of smectite associated with an increase in accumulation of kaolinite starting at ?15.6 Ma,

Cédric M. John; Thierry Adatte; Maria Mutti

2006-01-01

148

Clay mineral, geochemical and Sr-Nd isotopic fingerprinting of sediments in the Murray-Darling fluvial system, southeast Australia  

Microsoft Academic Search

Clay minerals, trace elements and isotopic signatures ( 87 Sr\\/ 86 Sr; 143 Nd\\/ 144 Nd) were investigated to fingerprint fine-grained sediments (52mm) from the major tributaries of the Murray-Darling fluvial system. Mineralogical, chemical and isotopic signatures in the river clays are clearly inherited from the assemblage of source rocks and soils in the upper catchments of each river. As

F. X. Gingele; P. de Deckker

2005-01-01

149

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

150

Clay mineral burial diagenesis: A case study from the Calabar flank of the Niger Delta  

NASA Astrophysics Data System (ADS)

Detailed clay mineralogic and chemical analyses of Tertiary subsurface sediments of the Agbada and Akata Formations, from two wells on the Calabar Flank of the Niger Delta, have been systematically studied with a view to understanding clay mineral burial diagenesis. Five principal clay minerals, smectite, illite, kaolinite, chlorite and various proportions of mixed-layer illite/smectite were identified. Seven major oxides (SiO 2, Al 2O 3, MgO, Fe 2O 3, CaO, Na 2O, K 2O) were analysed for with an atomic absorption spectrophotometer, with a view to ascertain any depth related variations. The geothermal gradient of the two wells (Uruan-1 and Uda-1) was also calculated. The results appear to suggest a transformation from smectite to a mixed-layer illite/smectite (I/S) phase. The transformation first goes to a random I/S phase, and then to ordered I/S and back to random I/S, even though postulated conditions for a complete transformation to illite did exist. It would therefore seem, from this case study, that neither temperature nor the availability of potassium is the principal factor controlling the transformation. Kaolinite and chlorite distribution does not exhibit any systematic trend that could be related to burial diagenesis. These results provoked an extensive literature review on the subject, and key ideas discerned are summarized here. The prognosis? In the author's opinion, we still have a lot to learn about the factors that control the mechanics and reaction extent of clay mineral burial diagenesis.

Braide, Sokari P.

151

Impact of clay mineral on air oxidation of PAH-contaminated soils.  

PubMed

This work investigated the impact of a clay mineral (bentonite) on the air oxidation of the solvent extractable organic matters (EOMs) and the PAHs from contaminated soils. EOMs were isolated from two coking plant soils and mixed with silica sand or bentonite. These samples, as well as raw soils and bentonite/soil mixtures, were oxidized in air at 60 and 100 °C for 160 days. Mineralization was followed by measuring the CO2 produced over the experiments. EOM, polycyclic aromatic compound (PAC), including PAH, contents were also determined. Oxidation led to a decrease in EOM contents and PAH concentrations, these diminutions were enhanced by the presence of bentonite. Transfer of carbon from EOM to insoluble organic matter pointed out a condensation phenomenon leading to a stabilization of the contamination. Higher mineralization rates, observed during the oxidation of the soil/bentonite mixtures, seem to indicate that this clay mineral had a positive influence on the transformation of PAC into CO2. PMID:24816462

Biache, Coralie; Kouadio, Olivier; Lorgeoux, Catherine; Faure, Pierre

2014-09-01

152

Syn- and post-sedimentary controls on clay mineral assemblages in a tectonically active basin, Andean Argentinean foreland  

NASA Astrophysics Data System (ADS)

In the northern part of the Calchaquí Valley (NW Argentina), Palaeogene Andean foreland sediments are represented by a 1400-metre-thick continental succession (QLC: Quebrada de Los Colorados Formation) consisting of claystones, siltstones, sandstones, and conglomerates representing sedimentation in fluvial-alluvial plains and alluvial fan settings. To understand the main syn- and postsedimentary variables controlling the clay mineral assemblages of this succession, we have studied the fine-grained clastic sediments by X-ray diffraction and electron microscopy, along with a detailed sedimentary facies analysis, for two representative sections. In the northern section, the whole succession was sampled and analysed by XRD, whereas in the second section, a control point 15 km to the south, only the basal levels were analysed. The XRD study revealed a strong contrast in clay mineral assemblages between these two sections as well as with sections in the central Calchaquí Valley studied previously. In the northernmost part of the study area, a complete evolution from smectite at the top to R3 illite/smectite mixed-layers plus authigenic kaolinite at the bottom, through R1-type mixed-layers in between, has been recognized, indicating the attainment of late diagenesis. In contrast, the clay mineral assemblages of equivalent foreland sediments cropping out only 15 km to the south contain abundant smectite and micas, subordinate kaolinite and chlorite, and no I/S mixed-layers to the bottom of the sequence. Early diagenetic conditions were also inferred in a previous study for equivalent sediments of the QLC Formation cropping out to the south, in the central Calchaquí Valley, as smectite occurs in basal strata. Burial depths of approximately 3000 m were estimated for the QLC Formation in the central and northern Calchaquí Valley; in addition, an intermediate to slightly low geothermal gradient can be considered likely for both areas as foreland basins are regarded as hypothermal basins. Consequently, the attainment of late diagenesis in the northernmost study area cannot be explained by significant differences in burial depth nor in geothermal gradient in relation to the section 15 km to the south nor with the central Calchaquí Valley. The formation of R3 mixed-layer I/S and authigenic kaolinite in the northern study area was most likely controlled by the circulation of hot, deep fluids along the reverse faults that bounded the Calchaquí valley. These faults were active during the Cenozoic, as evidenced by the syndepositional deformation features preserved in the studied sediments. Stress could also have been a driving force in burial diagenesis at the R3 mixed-layer I/S stage in these young continental sediments.

Do Campo, Margarita; Nieto, Fernando; del Papa, Cecilia; Hongn, Fernando

2014-07-01

153

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

USGS Publications Warehouse

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.

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

2013-01-01

154

Utilization of Hyperion data over Dongargarh, India, for mapping altered\\/weathered and clay minerals along with field spectral measurements  

Microsoft Academic Search

Hyperion data acquired over Dongargarh area, Chattisgarh (India), in December 2006 have been analysed to identify dominant mineral types present in the area, with special emphasis on mapping the altered\\/weathered and clay minerals present in the rocks and soils. Various advanced spectral processes such as reflectance calibration of the Hyperion data, minimum noise fraction transformation, spectral feature fitting (SFF) and

S. Bhattacharya; T. J. Majumdar; A. S. Rajawat; M. K. Panigrahi; P. R. Das

2012-01-01

155

Stable isotope geochemistry of sulfur bearing minerals and clay mineralogy of some soils and sediments in Loot Desert, central Iran  

E-print Network

Stable isotope geochemistry of sulfur bearing minerals and clay mineralogy of some soils Desert Stable isotope geochemistry is a unique technique to study the source of salts in soils and sediments. In the present research, sources of gypsum and other sulfur bearing minerals using stable isotope

Ahmad, Sajjad

156

Adsorption of iron cyanide complexes onto clay minerals, manganese oxide, and soil.  

PubMed

The adsorption characteristics of an iron cyanide complex, soluble Prussian blue KFe(III)[Fe(II)(CN)(6)], were evaluated for representative soil minerals and soil at pH 3.7, 6.4 and 9.7. Three specimen clay minerals (kaolinite, montmorillonite, and illite), two synthesized manganese oxides (birnessite and cryptomelane), and a Drummer soil from Indiana were used as the adsorbents. Surface protonation of variable charge sites increased with decreasing pH yielding positively charged sites on crystal edges and enhancing the attractive force between minerals and iron cyanide complexes. Anion adsorption on clays often is correlated to the metal content of the adsorbent, and a positive relationship was observed between iron or aluminum content and Prussian blue adsorption. Illite had high extractable iron and adsorbed more ferro-ferricyande anion, while kaolinite and montmorillonite had lower extractable iron and adsorbed less. However, less pH effect was observed on the adsorption of iron cyanide to manganese oxides. This may due to the manganese oxide mediated oxidation of ferrocyanide [Fe(II)(CN)(6)(4-)], to ferricyanide [Fe(III)(CN)(6)(3-)], which has a low affinity for manganese oxides. PMID:20665323

Kang, Dong-Hee; Schwab, A Paul; Johnston, C T; Banks, M Katherine

2010-09-01

157

The origin of Ba and REE-bearing aluminium-phosphate-sulphate minerals from the Lohrheim kaolinitic clay deposit (Rheinisches Schiefergebirge, Germany)  

Microsoft Academic Search

Two types of aluminium-phosphate-sulfate minerals are described for the first time from the Lohrheim kaolinitic clay deposit which was laid down during the Tertiary on Devonian rocks of the Rheinisches Schiefergebirge: type A is dominant in gorceixite BaAl3(PO4)2(OH)5 · H2O, type B is abundant in florencite-(Ce) CeAl3(PO4)2(OH)6 and goyazite SrAl3(PO4)2(OH)5· H2O. Both types resulted from weathering of pyritiferous parent material,

H. G. Dill; A. Fricke; K.-H. Henning

1995-01-01

158

Clay mineral content of continental shelf and river sediments, southern California  

USGS Publications Warehouse

This report contains data on the clay mineral content of 250 shelf surface-sediment samples from the California Continental Borderland (Tables 1, 2; Figures 1-7), 79 samples with depth in cores from Santa Monica Bay (Table 3; see Table 1 for surface sediment data for those same cores and for core locations), 24 suspended and 13 bottom sediment samples from rivers draining Southern California (Table 4), and six rock samples or composite rock samples from the Palos Verdes Headland (Table 4). This report is designed as the data repository and these data are discussed in a paper by Hein et al. (2001).

Hein, James R.; Dowling, Jennifer S.

2001-01-01

159

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

SciTech Connect

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.

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

2012-09-01

160

Clay mineral distributions in surface sediments of the Liaodong Bay, Bohai Sea and surrounding river sediments: Sources and transport patterns  

NASA Astrophysics Data System (ADS)

Clay mineralogy of surface sediments throughout the Liaodong Bay and surrounding fluvial samples has been analyzed in order to reveal sources and spatial transport patterns of the detrital fine-grained sediments. Four characteristic end-members in clay compositions were observed from four major provenances, respectively: high content of smectite and scarce chlorite from northern rivers, and Luan River, high illite and low smectite from southern rivers, highest content of illite from eastern rivers, mediate content from western rivers. The sources and distribution patterns of clay minerals are closely related to river inputs, the regional currents, and tide systems. The clays covered in the southwest (SW zone) are primarily supplied by the Luan River and the Liugu River. While the clays in the northern Liaodong Bay (North Zone) derived from the northern rivers seem to be transported mainly via the surface currents. The clay minerals in the southeast (SE zone) sourced from the Laotieshan passage are attributed to the northward residual currents. Furthermore, the materials resulted from bedrocks erosion may bring a few clay minerals.

Dou, Yanguang; Li, Jun; Zhao, Jingtao; Wei, Helong; Yang, Shouye; Bai, Fenglong; Zhang, Daolai; Ding, Xue; Wang, Libo

2014-02-01

161

Radiation Sensitivity of Natural Organic Matter: Clay Mineral Association Effects in the Callovo-Oxfordian Argillite  

SciTech Connect

Clay-rich low-organic carbon formations (e.g., Callovo-Oxfordian argillite in France and Opalinus Clay in Switzerland) are considered as host rocks for radioactive waste disposal. The clay-organic carbon has a strong impact on the chemical stability of the clays. For this reason, the nature of the clay-organic carbon, the release of hydrophilic organic compounds, namely, humic (HA) and fulvic acids (FA) and the radiation sensitivity of the undisturbed host rock organics was investigated. The clay sample originates from Oxfordian argillite (447 m depth, borehole EST 104). HA and FA were extracted following the standard International Humic Substance Society (IHSS) isolation procedure. Synchrotron based (C-, K-, Ca-, O- and Fe-edge XANES) scanning transmission X-ray microscopy (STXM) and FT-IR microspectroscopy was used to identify under high spatial resolution the distribution of clay-organic matter with different functionality using principal component and cluster analysis. The results show that in this old (Jurassic) geological formation, small parts of the organic inventory (1-5%) keeps the structure/functionality and can be mobilized as hydrophilic humic substance type material (HA and FA). Target spectra analysis shows best correlation for isolated humic acids with organics found in smectite-rich regions, whereas the extractable FA has better spectral similarities with the illite mixed layer minerals (MLM) regions. After radiation of 1.7 GGy under helium atmosphere the same rock sample area was investigated for radiation damage. Radiation damage in the smectite and illite-MLM associated organic matter is comparably low with 20-30% total oxygen mass loss and 13-18% total carbon mass loss. A critical dose dc of 2.5 GGy and a optical density after infinite radiation (OD?) of 54% was calculated under room temperature conditions. C(1s) XANES show a clear increase in Cdouble bond; length as m-dashC bonds especially in the illite-MLM associated organics. This results suggests a combination of the formation of Cdouble bond; length as m-dashC bond due to crosslinking via polymerization and mass loss due to bond breaking (scissioning) in the main chain or in side groups of the organic macromolecules upon irradiation.

Schäfer, T.; Michel, P; Claret, F; Beetz, T; Wirick, S; Jacobsen, C

2009-01-01

162

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

NASA Technical Reports Server (NTRS)

The Mars Science Laboratory (MSL) Rover, Curiosity spent approx 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 (approx 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 approx 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 021 band consistent with a trioctahedral phyllosilicate. A broad peak at approx 10A with a slight inflexion at approx 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 >60degC in the presence of water. Given estimated geothermal gradients on Mars temperatures <60 degC 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.

Bristow, Thomas; Blake, David; Bish, David L.; Vaniman, David; Ming, Douglas W.; Morris, Richard V.; Chipera, Steve; Rampe, Elizabeth B.; Farmer, Jack, D.; Treiman, Allan H; Downs, Robert; Morrison, Shaunna; Achilles, Cherie; DesMarais, David J.; Crisp, Joy A.; Sarrazin, Philippe; Morookian, John Michael; Grotzinger. John P.

2013-01-01

163

Ball clay  

USGS Publications Warehouse

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.

Virta, R. L.

2001-01-01

164

Mineral abundance determination: Quantitative deconvolution of thermal emission spectra  

Microsoft Academic Search

A linear retrieval (spectral deconvolution) algorithm is developed and applied to high-resolution laboratory infrared spectra of particulate mixtures and their end- members. The purpose is to place constraints on, and test the viability of, linear spectral deconvolution of high-resolution emission spectra. The effects of addition of noise, data reproducibility, particle size variation, an increasing number of minerals in the mixtures,

Michael S. Ramsey; Philip R. Christensen

1998-01-01

165

Zeolite-clay mineral zonation of volcaniclastic sediments within the McDermitt caldera complex of Nevada and Oregon  

USGS Publications Warehouse

Volcaniclastic sediments deposited in the moat of the collapsed McDermitt caldera complex have been altered chiefly to zeolites and potassium feldspar. The original rhyolitic and peralkaline ash-flow tuffs are included in conglomerates at the caldera rims and grade into a lacustrine series near the center of the collapse. The tuffs show a lateral zeolitic alteration from almost fresh glass to clinoptilolite, clinoptilolite-mordenite, and erionite; to analcime-potassium feldspar; and finally to potassium feldspar. Vertical zonation is in approximately the same order. Clay minerals in associated mudstones, on the other hand, show little lateral variation but a distinct vertical zonation, having a basal dioctahedral smectite, a medial trioctahedral smectite, and an upper dioctahedral smectite. The medial trioctahedral smectite is enriched in lithium (as much as 6,800 ppm Li). Hydrothermal alteration of the volcaniclastic sediments, forming both mercury and uranium deposits, caused a distinct zeolite and clay-mineral zonation within the general lateral zonation. The center of alteration is generally potassium feldspar, commonly associated with alunite. Potassium feldspar grades laterally and vertically to either clinoptilolite or clinoptilolite-mordenite, generally associated with gypsum. This zone then grades vertically and laterally into fresh glass. The clay minerals are a dioctahedral smectite, a mixed-layer clay mineral, and a 7-A clay mineral. The mixed-layer and 7-A clay minerals are associated with the potassium feldspar-alunite zone of alteration, and the dioctahedral smectite is associated with clinoptilolite. This mineralogical zonation may be an exploration guide for mercury and uranium mineralization in the caldera complex environment.

Glanzman, Richard K.; Rytuba, James J.

1979-01-01

166

Clay mineral weathering and contaminant dynamics in a caustic aqueous system. II. Mineral transformation and microscale partitioning  

NASA Astrophysics Data System (ADS)

Microscopic and spectroscopic studies were conducted to assess mineral transformation processes in aqueous suspensions of illite (Il), vermiculite (Vm) and montmorillonite (Mt) that were subjected to weathering in a simulated high-level radioactive tank waste leachate (0.05 m Al T, 2 m Na +, 1 m NO 3-, pH ˜14, Cs + and Sr 2+ present as co-contaminants). Time series (0 to 369 d) experiments were conducted at 298 K, with initial [Cs] 0 and [Sr] 0 concentrations from 10 -5 to 10 - mol kg -. Incongruent clay dissolution resulted in an accumulation of secondary aluminosilicate precipitates identified as nitrate-sodalite, nitrate-cancrinite and zeolite X, by molecular spectroscopy and electron microscopy (XRD, IR, NMR, SEM-EDS and TEM-EDS). Contaminant fate was dependent on competing uptake to parent clays and weathering products. TEM-EDS results indicated that high Il affinity for Cs was due to adsorption at frayed edge sites. The Il system also comprised Sr-rich aluminous precipitates after 369 d reaction time. In Mt systems, Cs and Sr were co-precipitated into increasingly recalcitrant spheroidal precipitates over the course of the experiment, whereas contaminant association with montmorillonite platelets was less prevalent. In contrast, Cs and Sr were found in association with weathered Vm particles despite the formation of spheroidal aluminosilicate precipitates that were comparable to those formed from Mt dissolution.

Choi, Sunkyung; Crosson, Garry; Mueller, Karl T.; Seraphin, Supapan; Chorover, Jon

2005-09-01

167

Clay mineral weathering and contaminant dynamics in a casutic aqueous sytem II. Mineral transformation and microscale partitioning  

SciTech Connect

Microscopic and spectroscopic studies were conducted to assess mineral transformation processes in aqueous suspensions of illite (Il), vermiculite (Vm) and montmorillonite (Mt) that were subjected to weathering in a simulated high-level radioactive tank waste leachate (0.05 m AlT, 2 m Na*, 1 m NO3 *, pH *14, Cs* and Sr2* present as co-contaminants). Time series (0 to 369 d) experiments were conducted at 298 K, with initial [Cs]0 and [Sr]0 concentrations from 10*5 to 10* mol kg*. Incongruent clay dissolution resulted in an accumulation of secondary aluminosilicate precipitates identified as nitrate-sodalite, nitrate-cancrinite and zeolite X, by molecular spectroscopy and electron microscopy (XRD, IR, NMR, SEM-EDS and TEM-EDS). Contaminant fate was dependent on competing uptake to parent clays and weathering products. TEM-EDS results indicated that high Il affinity for Cs was due to adsorption at frayed edge sites. The Il system also comprised Sr-rich aluminous precipitates after 369 d reaction time. In Mt systems, Cs and Sr were co-precipitated into increasingly recalcitrant spheroidal precipitates over the course of the experiment, whereas contaminant association with montmorillonite platelets was less prevalent. In contrast, Cs and Sr were found in association with weathered Vm particles despite the formation of spheroidal aluminosilicate precipitates that were comparable to those formed from Mt dissolution.

Choi, Sunkyung; Crosson, Garry S.; Mueller, Karl T.; seraphin, supapan; Chorover, Jon

2005-04-08

168

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

SciTech Connect

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.

Collins, Y.E.

1987-01-01

169

Mineral abundance determination: Quantitative deconvolution of thermal emission spectra  

Microsoft Academic Search

A linear retrieval (spectral deconvolution) algorithm is developed and applied to high-resolution laboratory infrared spectra of particulate mixtures and their end-members. The purpose is to place constraints on, and test the viability of, linear spectral deconvolution of high-resolution emission spectra. The effects of addition of noise, data reproducibility, particle size variation, an increasing number of minerals in the mixtures, and

Michael S. Ramsey; Philip R. Christensen

1998-01-01

170

Characteristics of Clay Minerals in the Fault Zone of TCDP and its Implications  

NASA Astrophysics Data System (ADS)

The 1999 Chi-Chi earthquake (Mw7.7) induced large ruptures at or near the surface and thus provides us a unique opportunity to study the thrust fault zone after a major earthquake. The materials in deep fault, recovered by the Taiwan Chelungpu-fault Drilling Project (TCDP) are less weathering by shallow or surface processes and enable us to determinate in-situ physical, mechanical and chemical characteristics in the fault zone. Meanwhile, clay reactions such as illite-smectite transformation are not only to estimate the maturity of diagenesis in sedimentary basin, but also to use as heating indicator of faulting in the fault zone. The mechanism of S-I reaction dominantly relies on four variables: 1) time, 2) heat, 3) the availability of K+ and 4) fluids, and the heat is the major factor in this transformation during the faulting. This may give us a hint to estimate the thermal history in the fault zone. The two main fault zones located in 1111m and 1153m deep, respectively, can be identified in the TCDP cores. Based on the XRD data, two characteristics of clay mineralogy can be distinguished in these two fault zones: 1) smectite-rich just occurs within a narrow black materials in 1111 fault zone, and other clay minerals are totally disappeared (only few illite); 2) all kaolinite were gone within a board area in the 1153 fault zone. The former, smectite-rich zone is impossible to be retrograded from illite due to lacking the smectite-illite mixed-layer clays occurred in this zone. It may be devitrified from glasses which were detected by the TEM. Meanwhile, ultra-fine particles in this zone are also identified by the TEM. These evidences, i.e. glasses, ultra-fine particles and smectile-rich zone, suggest that the black materials occurred in the 1111 m deep may be the candidate slip zone of the 1999 Chi-Chi earthquake and provide the information to calculate the fractured and heat energy produced by this event. The consumption of kaolinite occurs in the temperature ranging from 450°C to 550°C and the temperature of chlorite transformed to other minerals is higher than 800°C based on the TGA experiments. Therefore, all kaolinite gone and the existence of chlorite in the 1153 fault zone indicate that this fault zone has been suffered from heating events of 450°C- 800 °C in past earthquakes.

Kuo, L.; Song, S.; Chen, H.

2005-12-01

171

Ball clay  

USGS Publications Warehouse

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.

Virta, R. L.

2007-01-01

172

Mineralogic and isotopic constraints on impact related clay mineral alteration, in the Woodleigh impact structure, Western Australia  

NASA Astrophysics Data System (ADS)

Clay mineral fractions from one of the largest Phanerozoic impact structures, the Woodleigh impact structure were investigated by XRD, electron microscopy and K-Ar and stable isotopic studies. Samples were collected from the central uplifted Precambrian basement granitoid, conglomeratic rocks derived from reworked impact rocks, and from the Ordovician-Devonian sandstones located ˜30 km west of the central uplift. There are remarkable lateral and vertical variations in authigenic clay mineral compositions and illite crystallinity (IC) values (Kübler index). Clay minerals from shocked granitoid basement rocks are mainly smectite-rich (>75%) mixed-layer illite-smectite with some discrete illite formed as an alteration-product (replacement) of biotite. Clay minerals in the conglomeratic rocks consist of mainly illite and Fe-rich chlorite, and in the lower part of the section, chlorite-rich (>50%) mixed-layer chlorite-smectite. Smectite in the oxidised upper part of the conglomeratic section is probably a weathering- product. Clay minerals from the Ordovician-Devonian sandstones further away from the central part of the impact structure include illite, less chlorite, and in the Devonian strata smectite. IC values of the <2 mm grain-size fraction in the conglomeratic rocks range from 0.51 to 0.56 ^o? 2? in the upper part and from 0.75 to 0.82 ^o? 2? in the lower part of the section. Illites from the Ordovician-Devonian sandstones show significantly higher IC values ranging from 0.75 to 1.45 ^o? 2?. Results of the clay mineralogy suggest that variations of clay mineral compositions and IC values are related to the changes in rock lithology and the variable effects of impact-induced hydrothermal processes. K-Ar dating of the authigenic illites of the coarser size-fractions (2-1 ?m and 0.5-0.2 ?m) containing no smectite yield concordant ages around 365 Ma. These K-Ar age data are consistent with previous results (Uysal et al., 2001;EPSL, 192:281--289) and, together with stratigraphic age constraints, confirm that the impact event was coeval with the Late Devonian mass extinction. Woodleigh impact-related clay minerals have significantly high ?18O values from 13.4 to 18.9 ppm. The calculated fluid ?18O values ranges from 6.5 to 11.7 ppm that are highly enriched in 18O relative to seawater, meteoric water and most basinal brines and may indicate the hydrothermal fluids interacted with 18O-rich condensed meteoritic components injected into the crater floor.

Uysal, I. T.; Golding, S. D.; Mory, A. J.; Glikson, A. Y.

2003-04-01

173

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

E-print Network

, diffusion, reaction kinetics, K-ion selective electrode, energies of activation. Ogwada, R.A., and DKinetics of Ion Exchange on Clay Minerals and Soil: II. Elucidation of Rate-limiting Steps1 R. A.L. Sparks. 1986. Kinetics of ion exchange on clay minerals and soil: II. Elucidation of rate-limiting steps

Sparks, Donald L.

174

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

E-print Network

AN INVESTIGATION OF SOME OF THE EFFECTS OF ANHYDROUS AMMONIA ON THE CIAY MINERALS MONTMORILLONITE AND ILLITE A Dissertation By Ell Lamar Whiteley 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 January, 1959 Major Subject* Soil Physics AN INVESTIGATION OF SOME OF THE EFFECTS OF ANHYDROUS AMMONIA ON THE CLAY MINERALS MGNTMORILLONITE AND ILLITE A Dissertation By Eli Lamar...

Whiteley, Eli Lamar

2013-10-04

175

Sedimentary processes on the Mekong subaqueous delta: Clay mineral and geochemical analysis  

NASA Astrophysics Data System (ADS)

Sedimentary processes on the inner Mekong Shelf were investigated by examining the characteristics of sediments sampled in gravity cores at 15 locations, including grain size, clay mineralogy, sediment accumulation rates, and the elemental and stable carbon isotopic composition of organic matter (atomic C/N ratios and ?13C). Deltaic deposits exhibit contrasting characteristics along different sides of the delta plain (South China Sea, SCS hereafter, to the east and Gulf of Thailand, GOT hereafter, to the west) as well as on and off the subaqueous deltaic system. On one hand, cores recovered from the subaqueous delta in the SCS/GOT are consisted of poorly/well sorted sediments with similar/different clay mineral assemblage with/from Mekong sediments. Excess 210Pb profiles, supported by 14C chronologies, indicate either "non-steady" (SCS side) or "rapid accumulation" (GOT side) processes on the subaqueous delta. The ?13C and C/N ratio indicate a mixture of terrestrial and marine-sourced organic matter in the deltaic sediment. On the other hand, cores recovered from areas with no deltaic deposits or seaward of the subaqueous delta show excess 210Pb profiles indicating "steady-state" accumulation with a greater proportion of marine-sourced organic matter. Core analysis's relevance with local depositional environment and previous acoustic profiling are discussed.

Xue, Zuo; Paul Liu, J.; DeMaster, Dave; Leithold, Elana L.; Wan, Shiming; Ge, Qian; Nguyen, Van Lap; Ta, Thi Kim Oanh

2014-01-01

176

Anisotropy on the collective dynamics of water confined in swelling clay minerals.  

PubMed

Collective excitations of water confined in the interlayer space of swelling clay minerals were studied by means of inelastic neutron scattering. The effect of bidimensional confinement on the dynamics of the interlayer water was investigated by using a synthetic Na-saponite sample with a general formula of Si(7.3)Al(0.7)Mg(6)O(20)(OH)(4)Na(0.7) in a bilayer hydration state. Experimental results reveal two inelastic signals, different from those described for bulk water with a clear anisotropy on the low-energy excitation of the collective dynamics of interlayer water, this difference being stronger in the perpendicular direction. Results obtained for the parallel direction follow the same trend as bulk water, and the effect of the confinement is mainly manifested from the fact that clay interlayer water is more structured than bulk water. Data obtained in the perpendicular direction display a nondispersive behavior below a cutoff wavenumber value, Q(c), indicating a nonpropagative excitation below that value. Molecular dynamics simulations results agree qualitatively with the experimental results. PMID:22324768

Jiménez-Ruiz, M; Ferrage, E; Delville, A; Michot, L J

2012-03-15

177

Michaelis constant (K m ) of acid phospatase as affected by montmorillonite, illite, and kaolinite clay minerals.  

PubMed

The influence of Ca homoionic clay minerals (montmorillonite, illite, and kaolinite) on the activity,K m , andV m values of acid phosphatase was examined in model experiments. At each substrate (p-nitrophenyl phosphate) level tested, the addition of increasing amounts of clays (50, 100, and 150 mg, respectively) decreased the activity and increased theK m value from 1.43×10(-3) M PNP (in the soluble state) to 82.3×10(-3)M (montmorillonite), 8.02×10(-3) M (kaolinite), and 7.65×10(-3) M (illite) at the 150 mg level. The maximum enzyme reaction velocity (V m ) remained nearly constant at different amounts of kaolinite and illite, but increased remarkably with rising quantities of montmorillonite. Apparently, the substrate affinity of sorbed acid phosphatase is significantly lower with montmorillonite than with kaolinite or illite. This may be ascribed to an intensive sorption of both substrate and enzyme to the surface as well as to interlattice sites of montmorillonite. PMID:24232494

Makboul, H E; Ottow, J C

1979-09-01

178

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

SciTech Connect

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.

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

179

Heterogeneous Reactions of Gaseous Nitric Acid and Nitrogen Dioxide on the Clay Minerals Kaolinite and Pyrophyllite.  

NASA Astrophysics Data System (ADS)

Airborne clay mineral particles undergo long-range transport because of their small size. As a consequence, heterogeneous reactions on these particles may impact tropospheric photochemical cycles. Diffuse reflectance infrared spectroscopy provided identification of surface adsorbed products formed from the uptake of gaseous nitric acid and nitrogen dioxide on the prototype clay minerals kaolinite and pyrophyllite. The reaction of HNO3 on kaolinite generated several irreversibly adsorbed products on the octahedral aluminum surface, including monodentate, solvated, bidentate and bridged nitrate species and surface adsorbed water. Molecularly adsorbed nitric acid was detected on the tetrahedral silicon surface and a small absorbance displaying faster kinetics suggested that surface defect sites also play a role. Heating the reacted kaolinite to 373 K removed the surface adsorbed water and also caused a decrease of monodentate and solvated nitrate concurrent with an increase in bidentate and bridged nitrates, thereby suggesting an equilibrium between these species. Although molecularly adsorbed nitric acid was the dominant pyrophyllite product, all aluminum bound nitrate species except bidentate were observed, indicating the importance of layer edge reactive sites. Similar products were observed for the uptake of NO2 on kaolinite. Total nitrate concentrations were quantified using ion chromatography, allowing reactive uptake coefficients to be determined. Using BET surface areas, uptake coefficients for NO2 on kaolinite ranged from 8.0×10^{-8} to 2.1×10-7. The reaction was second order with respect to both NO2 and reactive surface sites, suggesting nitrite may also be formed. Strong kaolinite lattice vibrations prevented the detection of adsorbed nitrite, however, UV-visible spectroscopy identified gaseous HONO as a product for the reaction on wet kaolinite.

Hinrichs, R. Z.; Angelini, M. M.

2006-12-01

180

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

SciTech Connect

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.

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

181

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

E-print Network

), respectively, from bottom to top. The clay mineral assemblage of beds B1 and B2 was illite, kaolinite, and chlorite, while that of beds B3 and B4 was mainly kaolinite with minor illite. The bimodal particle defined lattice-fringe image. The illite crystallinity index exhibited a trend of downward decrease, while

Li, Zhaohui

182

CLAY MINERALOGY OF INSOLUBLE RESIDUES IN MARINE EVAPORITES.  

USGS Publications Warehouse

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.

Bodine, Marc W., Jr.

1985-01-01

183

Interplay between cataclasis, clay mineral diagenesis and porosity reduction in deformation bands in unconsolidated arkosic sands  

NASA Astrophysics Data System (ADS)

As a response to tectonic and gravitational stresses, unconsolidated sediments can develop zones of localized deformation, commonly described as deformation bands. These are tabular fault zones in high porosity rocks and sediments characterized by small offsets causing reduction of porosity through grain rotation, translation and fracturing. Classified by deformation mechanism and depth of formation, there are two main types of deformation bands: disaggregation bands, where compaction is achieved only by grain rotation and translation, and cataclastic bands, which show intense grain size reduction by grain fracturing. In various examples the porosity and permeability reduction in these fault zones inhibits the flow of fluids. The timing of deformation band formation relative to diagenesis and fluid migration is relevant in relation to the quality and connectivity of hydrocarbon or groundwater reservoirs. The investigated outcrop in a sandpit near Eisenstadt (Eisenstadt-Sopron Basin, Austria) exposes numerous conjugate deformation bands, which are formed in lower Miocene uncemented, arkosic sands and gravels. These deformation bands formed at shallow burial depth (< 1km) and are kinematically related to the nearby Eisenstadt Fault. This outcrop offers the unique possibility to investigate deformation bands with identical kinematic boundary conditions in highly variable sediments, i.e. with a wide range of different grain sizes from fine sand to coarse gravel, variable porosity and mineral content, different stages of diagenesis and carbonate-free or carbonatic sediments. The fact that cataclasis is one of the dominant mechanisms at these shallow depths (< 1km) is unusual and an exception to most cataclastic bands described in literature. This is probably related to the composition, coarse grain size and the high porosity of the sediments. The coarse host sediment mainly consists of detrital quartz, albite, biotite, sericite, muscovite and metamorphic lithoclasts. The dominant deformation mechanisms and the magnitude of porosity reduction in the carbonate-free lithologies are controlled by the initial mica content, mean grain size, level of alteration and albite content in the host rock. The studied deformation bands show a preferred fracturing of sericitized albite grains and the smearing of micas into the pore space. These processes increase the amount of phyllosilicates in the pore space and facilitate the growth of various authigenic clay minerals like smectite, vermiculite, kaolinite and illite. Because of the changed petrophysical properties the deformation bands show a different diagenetic evolution in comparison with the host rock. We identified 4 steps in the development from a high-porosity host rock to a low porosity deformation band. The measured reduction in porosity by up to 18% is associated with a permeability reduction, reflected in the retention of fluids along the deformation bands with the highest content of authigenic clay minerals.

Lommatzsch, Marco; Exner, Ulrike; Gier, Susanne

2013-04-01

184

Calcium-ammonium exchange experiments on clay minerals using a (45)Ca tracer technique in marine pore water.  

PubMed

Understanding cation exchange processes is important for evaluating early diagenetic and synsedimentary processes taking place in marine sediments. To quantify calcium (Ca) exchange and Ca-ammonium exchange in a seawater environment, we performed experiments with a radioactive (45)Ca tracer on clay mineral standards (Fithian illite, montmorillonite and kaolinite) and marine sediments from the North Atlantic Integrated Ocean Drilling Program Site U1306A in artificial seawater (ASW). The results show that equilibrium during the initial attachment of Ca as well as the exchange of Ca by [Formula: see text] is attained in less than 2 min. On average 8-20% of the exchangeable sites of the clay minerals were occupied by Ca in a seawater medium. The conditional selectivity coefficient, describing the [Formula: see text] exchange in ASW is mineral specific and it was determined to be 0.07 for montmorillonite, 0.05 for a natural marine sediment and 0.013 for Fithian illite. PMID:24437731

Ockert, Charlotte; Wehrmann, Laura M; Kaufhold, Stephan; Ferdelman, Tim G; Teichert, Barbara M A; Gussone, Nikolaus

2014-01-01

185

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

NASA Astrophysics Data System (ADS)

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.

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

1993-02-01

186

Plant Root Responses to Three Abundant Soil Minerals: Silicon, Aluminum and Iron  

Microsoft Academic Search

Silicon (Si), aluminum (Al), and iron (Fe) are the three most abundant minerals in soil; however, their effects on plants differ because they are beneficial, toxic, and essential to plant growth, respectively. High accumulation of silicon in the shoots helps some plants to overcome a range of biotic and abiotic stresses. However, plants vary in their ability to take up

Jian Feng Ma

2005-01-01

187

Environmental Weathering of Aluminosilicate Clay Minerals: Solid-State NMR Studies of Transformations Leading to Radionuclide Sequestration  

SciTech Connect

Mobilities of radionuclides (such as 137Cs and 90Sr) are governed by their interactions with natural soil particles in the saturated and unsaturated zones at Department of Energy sites. High surface area aluminosilicate clay minerals are a component of the natural soils beneath the leaking waste tanks at these sites and serve as possible radionuclide sorbents. However, due to the characteristics of the contaminant medium (high pH, high Al and high ionic strength), clay minerals are susceptible to transformations during exposure to tank waste leachates. We are currently studying the transformation of clays under specific chemical conditions that mimic the composition of known contaminant solutions. In these studies, specimen clay samples are reacted for varying time periods (up to one year) with simulated tank waste leachate solutions. Mineral dissolution and transformation are followed with solution analysis, x-ray diffraction and a number of other analytical methods. We report here results from 27Al MAS NMR at variable magnetic field strengths (up to 18.8 T), 29Si MAS NMR and 1H/29Si CPMAS NMR and evaluate these results along with those of other parallel analytic studies.

Mueller, Karl T.; Crosson, Garry; Chorover, Jon; Choi, Sunkyung

2004-03-28

188

Orientation and optical properties of methylene blue crystal for better understanding of interactions with clay mineral surface  

NASA Astrophysics Data System (ADS)

The properties of cationic dye Methylene blue (MB) adsorbed on diferent surfaces have been investigated intensively over the years and various models for the orientation of its cations have been proposed (Hang and Brindley, 1970; Bujdak et al., 2003; Li and Zare, 2004; Marr III et al., 1973; Bujdak, 2006).The main objective of this work is to investigate and determine orientation and optical properties of metylene blue crystal upon its crystallization on a glass slate and to use those findings in better understanding of interactions with clay minerals. Cationic dyes have very high affinity for clay surfaces and those interactions are easily detected, therefore these dyes are used to determine several properties of clay surfaces (morphology, layer charge, CEC). For this study, we have selected a group of MB crystal and carried out XRD analysis, polarized absorption spectra measurement (400 - 900 nm) and determination of optical properties (pleochroism, determination of twining and extinction angle) using polarizing microscope. Methylene blue crystals are exhibiting mostly needle like habitus with huge difference in width - length ratio. According to X-ray diffraction it is quite obvious that the y (b) axis is perpendicular to the crystal surface. The x (a) and z (c) axis lie in the crystal plane (010). Crystals exhibit prominent dichroism: from blue (E || elong.) to colorless. In accordance with current interpretation of MB spectra peaks at 647 and 570 nm can be assigned as dimer aggregation and peaks at 475 and 406 nm as higher level of aggregation. All of them exhibit pronounced polarization dependence. The group of peaks at lower energy (700 to 900 nm) do not show significant polarization dependence and they correspond to the J - aggregates. Peak at around 800 nm have been noticed as fluorescence active. In dependence with thickness of the crystals and vibration direction we have observed presence of polysynthetic twinning which can be compared with polysynthetic twinning of feldspar minerals. Final result of molecular polymerization is represented as crystal framework of methylene blue. Model of the MB molecular aggregation in the crystal structure could be used as a way for the interpretation of the thin layer structure and the molecular aggregation on the clay surface. References - Hang P.T. & Brindley G.W., (1970), Clays and Clay Minerals, 18, 203-212. - Bujdak J., Iyi N., Kaneko Y. and Sasai R., (2003), Clay Minerals (2003), 38, 561-572. - Li F. and Zare R.N., (2005), J. Phys. Chem. B 2005, 109, 3330-3333. - Marr III, H.E., Stewart, J.M. and Chiu, M.F., (1973), Acta Cryst. (1973), B29, 847. - Bujdak J., (2006), Applied Clay Science 34 (2006) 58 - 73

Miloševi?, Maja; Logar, Mihovil

2013-04-01

189

24. Altaner, S. P. & Ylagan, R. F. Comparison of structural models of mixed-layer illite-smectite and reaction mechanisms of smectite illitization. Clays Clay Minerals 45, 517533 (1997).  

E-print Network

24. Altaner, S. P. & Ylagan, R. F. Comparison of structural models of mixed-layer illite-smectite and reaction mechanisms of smectite illitization. Clays Clay Minerals 45, 517­533 (1997). 25. Ahn, J. H. & Peacor, D. R. A transmission and analytical electron microscopic study of the smectite to illite

Forchhammer, Mads C.

190

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

SciTech Connect

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.

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

1992-05-01

191

Sedimentological control on the clay mineral distribution in the marine and non-marine Palaeogene deposits of Mallorca (Western Mediterranean)  

NASA Astrophysics Data System (ADS)

During the Middle Eocene-Oligocene a marine and non-marine succession, about 1000 m thick, was deposited on Mallorca. Palaeoenvironmental interpretation of these deposits was obtained from sedimentological and palaeontological data in earlier studies. The non-marine environments recorded are: alluvial, fluvial (channel and flood plain deposits) and lacustrine (prevailing terrigenous, organic-rich or carbonate sedimentation). Marine environments are represented by littoral and shelf deposits. In most of these palaeoenvironments, terrigenous sedimentation prevailed except in the marine shelf, where mixed sedimentation was dominant, and in the carbonate and organic-rich lakes. In general, Palaeogene freshwater lakes were perennial, open and exorheic, with carbonate waters. The Palaeogene deposits were derived from Jurassic and Early Cretaceous pelagic and hemipelagic marls. The clay mineral assemblage of these source-area rocks was mostly smectite, interstratified illite-smectite and illite. The weathering of these materials under high temperature and rainfall favoured the hydrolysis of clay minerals and the formation of kaolinite. X-ray diffraction, TEM and EDX analysis were carried out on 108 samples of palaeogene mudstones. Clay minerals identified were illite, interstratified illite-smectite, smectite, chlorite and kaolinite. The various Palaeogene environments (marine, transitional and non-marine) can be distinguished on the basis of different clay mineral assemblages. These assemblages are related to weathering and diagenetic processes as well as to the distance from the source area. Alluvial sediments contain smectite and kaolinite with subordinate amounts of illite. All these clay minerals are of detrital origin. Smectite and kaolinite are present in all environments but the proportion of kaolinite to smectite increases with the distance from the source. The K-rich interstitial waters derived from illite hydrolysis in the source area favoured the formation of mixed-layer illite-smectite in the alluvial flood plain where the stagnation of waters during dry periods allowed the concentration of dissolved ions. Fluvial deposits contain interstratified illite-smectite, smectite, kaolinite, illite and chlorite in variable amounts. Variations in the proportion of illite and the occasional occurrence of chlorite was attributed to compositional differences in the source area and variations in the sediment supply input. The terrigenous and carbonate lakes preserved the detrital clay mineral assemblage carried by the rivers. Organic-rich lakes contain mainly kaolinite and smectite with less illite. Littoral deposits contain kaolinate and illite with minor amounts of smectite and interstratified smectite-illite. Shelf deposits are mostly formed by illite and kaolinite.

Inglès, M.; Ramos-Guerrero, E.

1995-01-01

192

Clays, common  

USGS Publications Warehouse

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.

Virta, R.L.

1998-01-01

193

Adsorption of reovirus to clay minerals: effects of cation-exchange capacity, cation saturation, and surface area.  

PubMed Central

The adsorption of reovirus to clay minerals has been reported by several investigators, but the mechanisms defining this association have been studied only minimally. The purpose of this investigation was to elucidate the mechanisms involved with this interaction. More reovirus type 3 was adsorbed, in both distilled and synthetic estuarine water, by low concentrations of montmorillonite than by comparable concentrations of kaolinite containing a mixed complement of cations on the exchange complex. Adsorption to the clays was essentially immediate and was correlated with the cation-exchange capacity of the clays, indicating that adsorption was primarily to negatively charged sites on the clays. Adsorption was greater with low concentrations of clays in estuarine water than in distilled water, as the higher ionic strength of the estuarine water reduced the electrokinetic potential of both clay and virus particles. The addition of cations (as chloride salts) to distilled water enhanced adsorption, with divalent cations being more effective than monovalent cations and 10(-2) M resulting in more adsorption than 10(-3) M. Potassium ions suppressed reovirus adsorption to montmorillonite, probably by collapsing the clay lattices and preventing the expression of the interlayer-derived cation-exchange capacity. More virus was adsorbed by montmorillonite made homoionic to various mono-, di-, and trivalent cations (except by montmorillonite homoionic to potassium) than by comparable concentrations of kaolinite homoionic to the same cations. The sequence of the amount of adsorption to homoionic montmorillonite was Al greater than Ca greater than Mg greater than Na greater than K; the sequence of adsorption to kaolinite was Na greater than Al greater than Ca greater than Mg greater than K. The constant partition-type adsorption isotherms obtained when the clay concentration was maintained constant and the virus concentration was varied indicated that a fixed proportion of the added virus population was adsorbed, regardless of the concentration of infectious particles. A heterogeneity within the reovirus population was indicated. PMID:6639022

Lipson, S M; Stotzky, G

1983-01-01

194

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

SciTech Connect

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.

Xu, Tianfu; Pruess, Karsten

2004-05-10

195

Clays and Clay Minerals. Vol. 40. No.3, 355-358, 1992. THE EFFECT OF CLAY DISPERSION ON THE SORPTION OF  

E-print Network

and intercrystalline water. Later, Chiou et al. (1979, 1983) proposed that the sorption of neutral organic chemicals ON THE SORPTION OF ACETONITRILE Key Words-Clay dispersion, Organic sorption, Partition, Sorption mechanism in the two solvents, is a constant. The partition mechanism has been extended to describe the sorption

Sparks, Donald L.

196

Mineral-produced high-pressure striae and clay polish: Key evidence for nonballistic transport of ejecta from Ries crater  

USGS Publications Warehouse

Recently discovered mineral-produced, deeply incised striae and mirror-like polish on broken surfaces of limestone fragments from the sedimentary ejecta of the Ries impact crater of southern Germany are described. The striae and polish were produced under high confining pressures during high-velocity nonballistic transport of the ejecta mass within the time span of the cratering event (measured in terms of seconds). The striae on these fragments were produced by scouring by small mineral grains embedded in the surrounding clay matrix, and the polish was formed under the same condition, by movements of relatively fragment-free clay against the fragment surfaces. The occurrence of these striae and polish is key evidence for estimating the distribution and determining the relative importance of nonballistic and ballistic transport of ejecta from the shallow Ries stony meteorite impact crater.

Chao, E.C.T.

1976-01-01

197

Broad-spectrum in vitro antibacterial activities of clay minerals against antibiotic-susceptible and antibiotic-resistant bacterial pathogens  

PubMed Central

SYNOPSIS Objectives The capacity to properly address the worldwide incidence of infectious diseases lies in the ability to detect, prevent, and effectively treat these infections. Therefore, identifying and analyzing inhibitory agents are worthwhile endeavors in an era when few new classes of effective antimicrobials have been developed. The use of geological nanomaterials to heal skin infections has been evident since the earliest recorded history, and specific clay minerals may prove valuable in the treatment of bacterial diseases, including infections for which there are no effective antibiotics, such as Buruli ulcer and multi-drug resistant infections. Methods We have subjected two iron-rich clay minerals, which have previously been used to treat Buruli ulcer patients, to broth culture testing of antibiotic-susceptible and -resistant pathogenic bacteria to assess the feasibility of using clay minerals as therapeutic agents. Results One specific mineral, CsAg02, demonstrated bactericidal activity against pathogenic Escherichia coli, extended-spectrum ?-lactamase (ESBL) E. coli, S. enterica serovar Typhimurium, Pseudomonas aeruginosa, and Mycobacterium marinum and a combined bacteriostatic/bactericidal effect against Staphylococcus aureus, penicillin-resistant S. aureus (PRSA), methicillin-resistant S. aureus (MRSA), and Mycobacterium smegmatis, while another mineral with similar structure and bulk crystal chemistry, CsAr02, had no effect on or enhanced bacterial growth. The <0.2 ?m fraction of CsAg02 and CsAg02 heated to 200°C or 550°C retained bactericidal activity, while cation-exchanged CsAg02 and CsAg02 heated to 900°C no longer killed E. coli. Conclusions Our results indicate that specific mineral products have intrinsic, heat-stable antibacterial properties, which could provide an inexpensive treatment against numerous human bacterial infections. PMID:18070832

HAYDEL, SHELLEY E.; REMENIH, CHRISTINE M.; WILLIAMS, LYNDA B.

2008-01-01

198

New information on the glacial history of the NW Barents Sea from clay minerals and radiocarbon dates  

NASA Astrophysics Data System (ADS)

Here we present results from new analyses on marine sediment cores that recovered subglacial and postglacial units deposited in the NW Barents Sea during the LGM and the Holocene. We have performed a pilot study on clay-mineral assemblages in three cores collected in palaeo-ice stream troughs surrounding Nordaustlandet (Hinlopen, Erik Eriksen and Kvitøya troughs) to investigate the provenance and pathways of subglacial sediment transported by the Barents Sea Ice Sheet (BSIS) during the LGM and of Holocene marine sediments. In all of the cores there is a clear change in clay mineral composition between the subglacial diamicts and the postglacial muds, and the clay-mineral assemblage in the diamicts is distinctive in each core. This suggests that the clay mineral composition records different pathways of subglacially transported detritus around eastern Svalbard. We interpret these data in relation to local source rocks on the Svalbard archipelago and in the central Barents Sea in order to provide new information regarding the BSIS dynamics during the last glacial period, about which there is still considerable debate for the central-northern Barents Sea sector (cf. Landvik and Ingolfsson, 2013). In addition, new radiocarbon ages from sediment cores around Nordaustlandet suggest that grounded ice had retreated from the shelf break north of Nordaustlandet and in Kvitøya Trough east of Svalbard by 13.3-13.6 14C kyrs BP. This is in line with deglacial dates of 13-13.3 14C kyrs BP from the other major troughs on the northern Barents Sea margin (Saint Anna and Franz Victoria troughs). In Hinlopen Trough our deglacial date confirms that the Polar Front was in the vicinity of the core site on the continental shelf some 20 km landward of the shelf break by 11.0 14C kyrs BP.

Hogan, Kelly; Dowdeswell, Julian; Hillenbrand, Claus-Dieter; Ehrmann, Werner

2014-05-01

199

Failure of Dietary Bentonite Clay, Silent Herder® Mineral Supplement, or Parenteral Banamine® to Alleviate Locoweed Toxicosis in Rats1  

Microsoft Academic Search

To evaluate treatments purportedly beneficial for livestock grazing locoweeds (LW), growing rats were fed diets containing 10 or 20% whole-plant Oxytropis sericea (LW) with and without Silent Herder® mineral mix (1.5% of diet) or ben- tonite clay (1.5% of diet). Pregnant female rats fed 10% LW were treated i.m. with Banamine® (a prostaglandins suppressor) or saline. The LW con- tained

Mari Dugarte-Stavanja; G. Stanley Smith; Thomas S. Edrington; Dennis M. Hallford

200

Geoscientific Applications of Particle Detection and Imaging Techniques withSpecial Focus on the Monitoring Clay Mineral Reactions  

NASA Astrophysics Data System (ADS)

The combined use of focused X-ray, electron, and ion beams offers a diverse range of analytical capabilities for characterizing nanoscale mineral reactions that occur in hydrous environments. Improved image and microanalytical techniques (e.g., electron diffraction and energy-dispersive X-ray spectroscopy), in combination with controlled sample environments, are currently leading to new advances in the understanding of fluid-mineral reactions in the Earth Sciences. One group of minerals playing a key role in the containment of radioactive waste and the underground storage of CO2 is the clay minerals: these small, expandable, and highly adsorbent hydrous phyllosilicates form important low-permeable geological barriers by which waste can be safely deposited. In this article we summarize some of the state-of-the-art particle and imaging techniques employed to predict the behavior of both engineered and natural clay mineral seals in proposed storage sites. Particular attention is given to two types of low-permeability geomaterials: engineered bentonite backfill and natural shale in the subsurface. These materials have contrasting swelling properties and degrees of chemical stability that require detailed analytical study for developing suitable disposal or storage solutions.

Warr, Laurence N.; Grathoff, Georg H.

201

Controls on detrital sedimentation in the Cariaco Basin during the last climatic cycle: insight from clay minerals  

NASA Astrophysics Data System (ADS)

A high resolution analysis of the clay-mineral content of sediments of the Cariaco Basin spanning the last climatic cycle was performed in order to determine how the detrital sedimentation in the basin records climatic oscillations at various timescales. At the scale of glacial-interglacial cycles, the clay-mineral content records changes in the geographic origin of the detrital supply, from a dominantly kaolinite- and smectite-rich southern source during glacial to a more illite-rich northerly source during interglacials. Though possibly influenced by eustatic variations, these changes mostly reflect the latitudinal fluctuations of the intertropical convergence zone (ITCZ). The Eemian shows an increased contribution from the northern source compared to the Holocene. During MIS3, seasonality modulates the effect of ITCZ position and leads to increased smectite contribution. Fluctuations of the smectite and kaolinite contents during Dansgaard/Oeschger cycles reflect changes of runoff intensity. Enhanced supplies in kaolinite during Heinrich-like events and stadials also suggest remobilizations of sediments deposited on the Unare platform resulting from rapid sea-level variations. The Younger Dryas is characterized by a significantly different clay-mineral association reflecting a drastic modification of terrigenous supply. An eolian contribution would explain this peculiar mineralogy, although local contributions cannot be ruled out. A similar event is noted at the MIS6-5 transition pointing for the occurrence of a Younger Dryas-like episode during Termination II.

Riboulleau, A.; Bout-Roumazeilles, V.; Tribovillard, N.

2014-06-01

202

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

USGS Publications Warehouse

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.

Foster, M.D.

1953-01-01

203

Mineralogy. Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite.  

PubMed

Meteorites exposed to high pressures and temperatures during impact-induced shock often contain minerals whose occurrence and stability normally confine them to the deeper portions of Earth's mantle. One exception has been MgSiO3 in the perovskite structure, which is the most abundant solid phase in Earth. Here we report the discovery of this important phase as a mineral in the Tenham L6 chondrite and approved by the International Mineralogical Association (specimen IMA 2014-017). MgSiO3-perovskite is now called bridgmanite. The associated phase assemblage constrains peak shock conditions to ~ 24 gigapascals and 2300 kelvin. The discovery concludes a half century of efforts to find, identify, and characterize a natural specimen of this important mineral. PMID:25430766

Tschauner, Oliver; Ma, Chi; Beckett, John R; Prescher, Clemens; Prakapenka, Vitali B; Rossman, George R

2014-11-28

204

Neogene clay mineral assemblages in the AND2A drill core (McMurdo Sound, Antarctica) and their implications for environmental change  

Microsoft Academic Search

Clay mineral assemblages in sediments from ANDRILL drill core AND-2A were used to reconstruct the Neogene palaeoenvironment. For the first time a clay mineral data set can be presented for southern McMurdo Sound, Ross Sea, Antarctica, that covers an expanded and fairly continuous Lower and Middle Miocene section. Although the occurrence of some authigenic smectites, zeolites and opal-CT documents diagenetic

Daniel Franke; Werner Ehrmann

2010-01-01

205

Oxygen isotope evidence of climate change from pedogenic clay minerals in the Himalayan molasse  

SciTech Connect

In this study, we examine the oxygen isotope ratios of smectite and kaolinite in a stratigraphic sequence of paleosols in the Siwalik Himalayan molasse on the Potwar Plateau, northern Pakistan. There is a 3-4{per_thousand} increase in the smectite {delta}{sup 18}O values synchronous with a {approximately}3.5{per_thousand} increase in {delta}{sup 18}O values of pedogenic calcite at 8.5-6.5 Ma. The covariation of the {delta}{sup 18}O values of smectite with calcite {delta}{sup 18}O values through time strongly suggests a pedogenic origin of smectite and that its {delta}{sup 18}O values reflect the oxygen isotope ratio of the soil water present during pedogenesis. These data show that the {delta}{sup 18}O values of clay minerals in paleosols in aggrading sedimentary sequences are viable paleoclimate indicators. Kaolinite {delta}{sup 18}O values are similar to smectite {delta}{sup 18}O values, as would be expected for pedogenic kaolinite, but there is greater variation in these data which we attribute to incomplete mineral separation. The measured permil oxygen isotope fractionation between calcite and smectite within individual paleosols is, on average, {approximately}3{per_thousand} higher than the equilibrium fractionation. This isotopic disequilibrium can be explained by the calcite forming predominantly during the dry winter season and the smectite forming predominantly during the wet summer season. The synchronous 3.5{per_thousand} increase in oxygen isotope ratios of smectite and calcite at 8.5-6.5 Ma indicates that this {sup 18}O/{sup 16}O increase is not due to diagenesis, but rather results from a climate change. The most likely causes of the {sup 18}O/ {sup 16}O increase in smectite and calcite are either increased aridity resulting in increased soil water evaporation (thus {sup 18}O enrichment) and/or a change from more continental to more marine-sourced precipitation. 83 refs., 8 figs., 2 tabs.

Stern, L.A.; Chamberlain, C.P.; Reynolds, R.C.; Johnson, G.D. [Dartmouth College, Hanover, NH (United States)] [Dartmouth College, Hanover, NH (United States)

1997-02-01

206

Oxygen isotope fractionation effects in soil water via interaction with cations (Mg, Ca, K, Na) adsorbed to phyllosilicate clay minerals  

NASA Astrophysics Data System (ADS)

In isotope-enabled hydrology, soil and vadose zone sediments have been generally considered to be isotopically inert with respect to the water they host. This is inconsistent with knowledge that clay particles possessing an electronegative surface charge and resulting cation exchange capacity (CEC) interact with a wide range of solutes which, in the absence of clays, have been shown to exhibit ?18O isotope effects that vary in relation to the ionic strength of the solutions. To investigate the isotope effects caused by high CEC clays in mineral-water systems, we created a series of monominerallic-water mixtures at gravimetric water contents ranging from 5% to 32%, consisting of pure deionized water of known isotopic composition with homoionic (Mg, Ca, Na, K) montmorillonite. Similar mixtures were also created with quartz to determine the isotope effect of non-, or very minimally-, charged mineral surfaces. The ?18O value of the water in these monominerallic soil analogs was then measured by isotope ratio mass spectrometry (IRMS) after direct headspace CO2 equilibration. Mg- and Ca-exchanged homoionic montmorillonite depleted measured ?18O values up to 1.55‰ relative to pure water at 5% water content, declining to 0.49‰ depletion at 30% water content. K-montmorillonite enriched measured ?18O values up to 0.86‰ at 5% water content, declining to 0.11‰ enrichment at 30% water. Na-montmorillonite produces no measureable isotope effect. The isotope effects observed in these experiments may be present in natural, high-clay soils and sediments. These findings have relevance to the interpretation of results of direct CO2-water equilibration approaches to the measurement of the ?18O value of soil water. The adsorbed cation isotope effect may bear consideration in studies of pedogenic carbonate, plant-soil water use and soil-atmosphere interaction. Finally, the observed isotope effects may prove useful as molecular scale probes of the nature of mineral-water interactions.

Oerter, Erik; Finstad, Kari; Schaefer, Justin; Goldsmith, Gregory R.; Dawson, Todd; Amundson, Ronald

2014-07-01

207

Clay mineral evidence of nepheloid layer contributions to the Heinrich layers in the northwest Atlantic  

Microsoft Academic Search

The clay fraction of four cores drilled in the north Atlantic Ocean was studied at a very high resolution over the last 150 ka in order to record the mineralogical signature of Heinrich events. Factor analysis of clay mineralogy establishes that three independent factors represent the main variations: a `detrital factor' (illite + chlorite + kaolinite), a `smectite factor', and

Viviane Bout-Roumazeilles; Elsa Cortijo; Laurent Labeyrie; Pierre Debrabant

1999-01-01

208

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

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.

Pollastro, R. M.

1982-01-01

209

Climatic and stratigraphic implications of clay mineral changes in Paleocene/Eocene boundary strata -- Eastern United States  

SciTech Connect

A major change in the clay mineral suite from predominantly illite/smectite and illite to predominantly kaolinite is present in uppermost Paleocene neritic deposits in the Salisbury embayment of the northeastern US. The clay mineral change occurred during a time of relatively high sea level and is associated with biotic, climatic, and oceanographic changes. This kaolinite increase in middle-latitude areas of the western North Atlantic Ocean, and similar increases in coeval deep-marine sediments off Antarctica and in the eastern North Atlantic Ocean, suggests that intensified weathering due to increased temperature and precipitation was widespread in the latest Paleocene. In the Salisbury embayment, kaolinite proportions rapidly increase from less than 5% in upper Paleocene strata to maximum values of 50 to 60% near the top of the Paleocene (top of calcareous nannofossil Zone NP 9). High kaolinite proportions continue into the lowest Eocene strata (lowermost zone NP 10), but the kaolinite proportion rapidly decreases to 5% or less within the lower part of Zone NP 10. The pattern of kaolinite increasing to maximum values in the latest Paleocene, followed by decreasing values in the earliest Eocene can be used for correlation within the upper Paleocene and lower Eocene units in the Salisbury embayment. On this basis, it is suggested that during the early Eocene, large parts of the uppermost Paleocene and lowermost Eocene clay were eroded from landward parts of the basin.

Gibson, T.G.; Bybell, L.M.; Owens, J.P.; Mason, D.B.; McCartan, L.; Snow, J.N. (Geological Survey, Reston, VA (United States))

1994-03-01

210

[Mineralogy and genesis of mixed-layer clay minerals in the Jiujiang net-like red soil].  

PubMed

Mineralogy and genesis were investigated using X-ray diffraction (XRD), Fourier infrared absorption spectroscopy (FTIR) and high resolution transmission electron microscopy (HRTEM) to understand the mineralogy and its genesis significance of mixed-layer clay minerals in Jiujiang red soil section. XRD and FTIR results show that the net-like red soil sediments are composed of illite, kaolinite, minor smectite and mixed-layer illite-smectite and minor mixed-layer kaolinite-smectite. HRTEM observation indicates that some smectite layers have transformed into kaolinite layers in net-like red soil. Mixed-layer illite-smectite is a transition phase of illite transforming into smectite, and mixed-layer kaolinite-smectite is a transitional product relative to kaolinite and smectite. The occurrence of two mixed-layer clay species suggests that the weathering sequence of clay minerals in net-like red soil traversed from illite to mixed-layer illite-smectite to smectite to mixed-layer kaolinite-smectite to kaolinite, which indicates that net-like red soil formed under a warm and humid climate with strengthening of weathering. PMID:23285883

Yin, Ke; Hong, Han-Lie; Li, Rong-Biao; Han, Wen; Wu, Yu; Gao, Wen-Peng; Jia, Jin-Sheng

2012-10-01

211

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)

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.

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

2001-01-01

212

doi:10.1016/j.gca.2005.04.004 Clay mineral weathering and contaminant dynamics in a caustic aqueous system  

E-print Network

--Microscopic and spectroscopic studies were conducted to assess mineral transformation processes in aqueous suspensions of illite site comprise micaceous weathering products illite, vermiculite and montmorillonite (Serne et al., 2001 paper, we reported on the time-dependent coupling between Cs and Sr uptake and clay mineral (illite

Chorover, Jon

213

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

214

Conformation heterogeneity and mobility of surfactant molecules in intercalated clay minerals studied by solid-state NMR  

SciTech Connect

The conformation heterogeneity and mobility of surfactant molecules in intercalated montmorillonite clay minerals have been investigated using variable-temperature solid-state {sup 13}C NMR and two-dimensional proton wide-line separation (2D WISE) {sup 1}H--{sup 13}C NMR spectroscopy. Previous FTIR studies by Vaia et al. for the first time revealed the existence of a gauche conformation of surfactant molecules in clay minerals and further illustrated the transition from an ordered conformation, to a liquid crystalline state, to completely liquid-like behavior. The NMR study reported in this paper clearly demonstrates the coexistence of order and disordered chain conformations. Two main resonance peaks are resolved and associated with the backbone alkyl chains: the resonance at 33 ppm corresponds to the ordered conformation (all-trans), and the resonance at 30 ppm corresponds to the disordered conformation (mixture of trans and gauche). The NMR technique allows detailed characterization and quantification of the conformational heterogeneity, which is difficult to determine by other techniques. Furthermore, variable-temperature NMR also directly provides quantitative information on the rigidity of the different conformations. Results from cross-polarization time constant T{sub CH} measurements along with 2D WISE NMR suggest that molecules in the ordered all-trans conformation are as rigid as those in solid crystalline materials and that molecules in the disordered conformation are similar to those in liquid crystalline materials. Upon heating, the molecules in the disordered conformation remain more or less unchanged, while the molecules in the ordered conformation become disordered. However, the intercalated molecules in the clay minerals never attained the complete liquid-like behavior even after all the bound surfactant assumed a disordered conformation.

Wang, L.Q.; Liu, J.; Exarhos, G.J.; Flanigan, K.Y.; Bordia, R.

2000-04-06

215

The role of clay minerals in the reduction of nitrate in groundwater by zero-valent iron.  

PubMed

Bench-scale batch experiments were performed to investigate the feasibility of using different types of clay minerals (bentonite, fuller's earth, and biotite) with zero-valent iron for their potential utility in enhancing nitrate reduction and ammonium control. Kinetics experiments performed with deionized water (DW) and groundwater (GW) revealed nitrate reduction by Fe(0) proceeded at significantly faster rate in GW than in DW, and such a difference was attributed to the formation of green rust in GW. The amendment of the minerals at the dose of 25 g L(-1) in Fe(0) reaction in GW resulted in approximately 41%, 43%, and 33% more removal of nitrate in 64 h reaction for bentonite, fuller's earth, and biotite, respectively, compared to Fe(0) alone reaction. The presumed role of the minerals in the rate enhancement was to provide sites for the formation of surface bound green rust. Bentonite and fuller's earth also effectively removed ammonium produced from nitrate reduction by adsorption, with the removal efficiencies significantly increased with the increase in mineral dose above 5:1 Fe(0) to mineral mass ratio. Such a removal of ammonium was not observed for biotite, presumably due to its lack of swelling property. Equilibrium adsorption experiments indicated bentonite and fuller's earth had maximum ammonium adsorption capacity of 5.6 and 2.1 mg g(-1), respectively. PMID:20797759

Cho, Dong-Wan; Chon, Chul-Min; Jeon, Byong-Hun; Kim, Yongje; Khan, Moonis Ali; Song, Hocheol

2010-10-01

216

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

SciTech Connect

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.

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

2007-03-01

217

Ball clay  

USGS Publications Warehouse

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.

Virta, R. L.

2000-01-01

218

Post-Fire Spatial Patterns of Soil Nitrogen Mineralization and Microbial Abundance  

PubMed Central

Stand-replacing fires influence soil nitrogen availability and microbial community composition, which may in turn mediate post-fire successional dynamics and nutrient cycling. However, fires create patchiness at both local and landscape scales and do not result in consistent patterns of ecological dynamics. The objectives of this study were to (1) quantify the spatial structure of microbial communities in forest stands recently affected by stand-replacing fire and (2) determine whether microbial variables aid predictions of in situ net nitrogen mineralization rates in recently burned stands. The study was conducted in lodgepole pine (Pinus contorta var. latifolia) and Engelmann spruce/subalpine fir (Picea engelmannii/Abies lasiocarpa) forest stands that burned during summer 2000 in Greater Yellowstone (Wyoming, USA). Using a fully probabilistic spatial process model and Bayesian kriging, the spatial structure of microbial lipid abundance and fungi-to-bacteria ratios were found to be spatially structured within plots two years following fire (for most plots, autocorrelation range varied from 1.5 to 10.5 m). Congruence of spatial patterns among microbial variables, in situ net N mineralization, and cover variables was evident. Stepwise regression resulted in significant models of in situ net N mineralization and included variables describing fungal and bacterial abundance, although explained variance was low (R2<0.29). Unraveling complex spatial patterns of nutrient cycling and the biotic factors that regulate it remains challenging but is critical for explaining post-fire ecosystem function, especially in Greater Yellowstone, which is projected to experience increased fire frequencies by mid 21st Century. PMID:23226324

Smithwick, Erica A. H.; Naithani, Kusum J.; Balser, Teri C.; Romme, William H.; Turner, Monica G.

2012-01-01

219

Sediment sources and their contribution along northern coast of the South China Sea: Evidence from clay minerals of surface sediments  

NASA Astrophysics Data System (ADS)

Clay minerals of surface sediment samples from nine bays/harbors along northern coast of the South China Sea (SCS) are used for sediment sources and contribution estimation in the study areas. Results reveal that sediments in the study bays/harbors seem to be a mixture of sediments from the Pearl, Hanjiang River and local islands/rivers, but their clay mineral assemblage is distinct from that of Luzon and Taiwan sediments, indicating that sediments are derived mainly from the neighboring sources through riverine input and partly from localized sediments. Due to input of local sediments in the northern SCS, sediments from both east of the Leizhou Peninsula (Area IV) and next to the Pearl River estuary (PRE, Area II) have high smectite percent. Affected by riverine input of the Pearl and Hanjiang Rivers, sediments in west of the PRE (Area III) and east of the PRE (Area I) have high illite (average 47%) and kaolinite (54%) percents, respectively. Sediment contributions of various major sources to the study areas are estimated as the following: (1) the Hanjiang River provide 95% and 84% sediments in Areas I and II, respectively, (2) the Pearl River supply 79% and 29% sediments in Areas III and IV, respectively and (3) local sediments contribute the rest and reach the maximum (˜71%) in Area IV.

Liu, Jianguo; Yan, Wen; Chen, Zhong; Lu, Jun

2012-09-01

220

Evolution of East Asian monsoon: Clay mineral evidence in the western Philippine Sea over the past 700 kyr  

NASA Astrophysics Data System (ADS)

Clay mineral assemblage of the core MD06-3047 in the western Philippine Sea has been used to trace sediment provenance and transport process and thus to constrain the East Asian monsoon evolution as well as its forcing mechanism over the past 700 kyr. Clay minerals mainly consist of smectite (61%) and illite (23%), with minor chlorite (10%) and kaolinite (6%). Provenance analyses suggest that the smectite originates predominantly from the alteration of nearby Luzon volcanic rocks. Illite is primarily derived from the Asian continent with eolian origin. Illite contents show strong glacial/interglacial cyclicity as constrained by oxygen isotope stratigraphy. Variations of illite contents are ultimately controlled by the East Asian monsoon evolution, characterized by higher illite values during glacials with relatively stronger East Asian winter monsoon but weaker East Asian summer monsoon. During interglacials, enhanced East Asian summer monsoon and rainfall could produce more smectite with poor crystallinity from Luzon to the study core. Spectral analyses of illite content and smectite crystallinity display a strong periodicity at 100 kyr for the East Asian winter monsoon and 100 kyr, 30 kyr, and 23 kyr periodicities for the East Asian summer monsoon, respectively, suggesting the unique forcing processes of the East Asian winter monsoon from high-latitudes (i.e., ice volume) and the East Asian summer monsoon from both high-latitudes and low-latitudes (i.e., tropical Pacific).

Xu, Zhaokai; Li, Tiegang; Wan, Shiming; Nan, Qingyun; Li, Anchun; Chang, Fengming; Jiang, Fuqing; Tang, Zheng

2012-10-01

221

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

PubMed Central

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

Rosenzweig, William D.; Stotzky, G.

1979-01-01

222

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...

223

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)

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.

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

2010-12-01

224

Clay mineral weathering and contaminant dynamics in a caustic aqueous system. I. Wet chemistry and aging effects  

NASA Astrophysics Data System (ADS)

Caustic high level radioactive waste induces mineral weathering reactions that can influence the fate of radionuclides released in the vicinity of leaking storage tanks. The uptake and release of Cs I and Sr II were studied in batch reactors of 2:1 layer-type silicates—illite (Il), vermiculite (Vm) and montmorillonite (Mt)—under geochemical conditions characteristic of leaking tank waste at the Hanford Site in WA (0.05 m Al T, 2 m Na +, 1 m NO 3-, pH ˜14, Cs and Sr present as co-contaminants). Time series (0 to 369 d) experiments were conducted at 298 K, with initial [Cs] 0 and [Sr] 0 concentrations from 10 -5 to 10 -3 mol kg -1. Clay mineral type affected the rates of (i) hydroxide promoted dissolution of Si, Al and Fe, (ii) precipitation of secondary solids and (iii) uptake of Cs and Sr. Initial Si release to solution followed the order Mt > Vm > Il. An abrupt decrease in soluble Si and/or Al after 33 d for Mt and Vm systems, and after 190 d for Il suspensions was concurrent with accumulation of secondary aluminosilicate precipitates. Strontium uptake exceeded that of Cs in both rate and extent, although sorbed Cs was generally more recalcitrant to subsequent desorption and dissolution. After 369 d reaction time, reacted Il, Vm and Mt solids retained up to 17, 47 and 14 mmol kg -1 (0.18, 0.24 and 0.02 ?mol m -2) of Cs, and 0, 27 and 22 mmol kg -1 (0, 0.14 and 0.03 ?mol m -2) Sr, respectively, which were not removed in subsequent Mg exchange or oxalic acid dissolution reactions. Solubility of Al and Si decreased with initial Cs and Sr concentration in Mt and Il, but not in Vm. High co-contaminant sorption to the Vm clay, therefore, appears to diminish the influence of those ions on mineral transformation rates.

Choi, Sunkyung; Amistadi, Mary Kay; Chorover, Jon

2005-09-01

225

Effect of chlorine in clay-mineral specimens prepared on silver metal-membrane mounts for X-ray powder diffraction analysis  

USGS Publications Warehouse

Silver metal-membrane filters are commonly used as substrates in the preparation of oriented clay-mineral specimens for X-ray powder diffraction (XRD). The silver metal-membrane filters, however, present some problems after heat treatment if either the filters or the samples contain significant amounts of chlorine. At elevated temperature, the chloride ions react with the silver substrate to form crystalline compounds. These compounds change the mass-absorption coefficient of the sample, reducing peak intensities and areas and, therefore, complicating the semiquantitative estimation of clay minerals. A simple procedure that eliminates most of the chloride from a sample and the silver metal-membrane substrate is presented here.

Poppe, L. J.; Commeau, J. A.; Pense, G. M.

1989-01-01

226

Near-infrared reflectance spectra of mixtures of kaolin-group minerals: use in clay mineral studies  

USGS Publications Warehouse

Near-infrared (NIR) reflectance spectra for mixtures of ordered kaolinite and ordered dickite have been found to simulate the spectral response of disordered kaolinite. The amount of octahedral vacancy disorder in nine disordered kaolinite samples was estimated by comparing the same spectra to the spectra of reference mixtures. The resulting estimates are consistent with previously published estimates of vacancy disorder for similar kaolin minerals that were modeled from calculated X-ray diffraction patterns. -from Authors

Crowley, J. K.; Vergo, N.

1988-01-01

227

Clay mineral weathering and contaminant dynamics in a casutic aqueous sytem II. Mineral transformation and microscale partitioning  

Microsoft Academic Search

Microscopic and spectroscopic studies were conducted to assess mineral transformation processes in aqueous suspensions of illite (Il), vermiculite (Vm) and montmorillonite (Mt) that were subjected to weathering in a simulated high-level radioactive tank waste leachate (0.05 m AlT, 2 m Na*, 1 m NO3 *, pH *14, Cs* and Sr2* present as co-contaminants). Time series (0 to 369 d) experiments

Sunkyung Choi; Garry S. Crosson; Karl T. Mueller; supapan seraphin; Jon Chorover

2005-01-01

228

Pedogenic clay–mineral transformation in the Weald Basin: implications for Early Cretaceous hinterland climate reconstructions  

Microsoft Academic Search

A thin (approximately 1 m) mottled bed from within the non-marine Wealden sediments of southeast England has been studied mineralogically. This bed is interpreted to have formed through soil processes acting shortly after deposition. Its clay mineralogy has been altered from a detrital vermiculite, illite, kaolinite assemblage to one of an ordered illite–smectite (IS ordering with 15–50% smectite), illite and

Kevin G. G. Taylor

1996-01-01

229

Cesium and Strontium Uptake to Clay Minerals and Their Weathering Products in a Caustic Waste  

Microsoft Academic Search

Weathering behavior and contaminant (Sr and Cs) uptake by specimen clays (illite, vermiculite, montmorillonite and kaolinite) and their secondary solid phase products were studied in batch systems under geochemical conditions characteristic of leaking tank waste at the Hanford Site in WA (0.05 M AlT, 2 M Na+, 1 M NO3 -, pH â14, Cs+ and Sr2+ present as co-contaminants). Time

Sunkyung Choi; Mary Kay Amistadi; Supapan Seraphin; Jon Chorover

2004-01-01

230

Clay Mineral Formation and Evolution in an Experimental Basaltic Weathering Profile  

NASA Astrophysics Data System (ADS)

This work reports on a new experimental approach aimed at understanding basaltic weathering profile chemical evolution processes using a unique packed-bed flow through reactor design that enables in-situ analysis of undisturbed alteration minerals.

Hurowitz, J. A.

2009-03-01

231

Sorption of organic cations to phyllosilicate clay minerals: CEC-normalization, salt dependency, and the role of electrostatic and hydrophobic effects.  

PubMed

Sorption to the phyllosilicate clay minerals Illite, kaolinite, and bentonite has been studied for a wide variety of organic cations using a flow-through method with fully aqueous medium as the eluent. Linear isotherms were observed at concentrations below 10% of the cation-exchange capacity (CEC) for Illite and kaolinite and below 1 mmol/kg (<1% CEC) for bentonite. Sorption to clays was strongly influenced by the electrolyte composition of the eluent but with a consistent trend for a diverse set of compounds on all clays, thus allowing for empirical correction factors. When sorption affinities for a given compound to a given clay are normalized to the CEC of the clay, the differences in sorption affinities between clays are reduced to less than 0.5 log units for most compounds. Although CEC-normalized sorption of quaternary ammonium compounds to clay was up to 10-fold higher than CEC-normalized sorption to soil organic matter, CEC-normalized sorption for most compounds was comparable between clays and soil organic matter. The clay fraction is thus a potentially relevant sorption phase for organic cations in many soils. The sorption data for organic cations to clay showed several regular trends with molecular structure but also showed quite a few systematic effects that we cannot explain. A model on the basis of the molecular size and charge density at the ionized nitrogen is used here as a tool to obtain benchmark values that elucidate the effect of specific polar moieties on the sorption affinity. PMID:24266737

Droge, Steven T J; Goss, Kai-Uwe

2013-12-17

232

Weathering and clay mineral formation in two Holocene soils and in buried paleosols in Tadjikistan: towards a Quaternary paleoclimatic record in Central Asia  

Microsoft Academic Search

The upper part of the Karamaydan section, Tadjikistan, shows the most detailed loess–paleosol sequence yet known for the Brunhes chron, and the central and lower parts of the Chashmanigar section provide similar detail for most of the Matuyama chron. To enable paleoclimates to be deduced, the primary and secondary minerals in the silt and clay fractions must be determined separately

A. Bronger; R. Winter; S. Sedov

1998-01-01

233

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

Microsoft Academic Search

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

Werner Ehrmann

1998-01-01

234

Evolution of clay mineral assemblages and organic matter in the late glacial-Holocene sedimentary infill of Lake Annecy, (northwestern Alps): paleoenvironmental implications  

Microsoft Academic Search

The basin fill of Lake Annecy was investigated from a 44 m core which reached down to glacial sediments of the last glaciation (called Würm in the alpine areas). We analyzed three main parameters: sediment texture (optical microscopy and laser microgranulometry), clay mineral assemblages (CMA by XRD), and organic matter (OM by Rock-Eval pyrolysis). Settling of suspended load, under variable

F. Manalt; C. Beck; J.-R. Disnar; J.-F. Deconinck; P. Recourt

2001-01-01

235

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

236

Cesium and Strontium Uptake to Clay Minerals and Their Weathering Products in a Caustic Waste  

SciTech Connect

Weathering behavior and contaminant (Sr and Cs) uptake by specimen clays (illite, vermiculite, montmorillonite and kaolinite) and their secondary solid phase products were studied in batch systems under geochemical conditions characteristic of leaking tank waste at the Hanford Site in WA (0.05 M AlT, 2 M Na+, 1 M NO3 -, pH {approx}14, Cs+ and Sr2+ present as co-contaminants). Time series experiments were conducted from 0 to 369 days, with initial Cs+ and Sr2+ concentrations ranging from 10-5 to 10-3 M. Cesium sorption after 369 d reaction was the greatest in the order of vermiculite, illite, montmorillonite and kaolinite at 10-3 M Cs/Sr. In the case of Sr, vermiculite showed highest Sr sorption and was followed by kaolinite, montmorillonite and illite at highest loading Cs/Sr after 369 d. Secondary phase products were feldspathoid sodium aluminum nitrate silicate, sodium aluminum nitrate silicate hydrate, Na-Al chabazite and zeolite X in weathered clays. Discrete Sr single phases were found in kaolinite and illite systems after 369 d at 10-3 M Cs/Sr.

Choi, Sunkyung; Amistadi, Mary Kay; Seraphin, Supapan; Chorover, Jon

2004-03-28

237

Monitoring nitrogen leaching for the evaluation of the Dutch minerals policy for agriculture in clay regions.  

PubMed

This paper presents the results of the Dutch monitoring program for agriculture in the clay regions for the period 1996-2000 and evaluates the monitoring strategy. A wide range of farms (25 to 85%) had a NO3--N concentration in tile drainwater higher than the EU standard of 11.3 mg/l. The low figure is related to wet winters; the high, to dry winters. Arable farms are more prone to NO3- leaching than dairy farms. On arable farms, about 25% of the N surplus leached to groundwater and tile drainwater, on dairy farms this was about 15%. N in tile drainwater has shown to be the best indicator for monitoring the effects of farming practice changes in the clay regions. The average NO3--N concentration in tile drainwater was 18.8 and 3.2 mg/l in borehole water on farms where both were monitored. It is known that N use has a relationship with NO3- in tile drainwater and not with NH4+ and organic N. The presented results indicate that crop rotation and precipitation strongly influence NO3- concentration in tile drainwater. PMID:12805827

Fraters, D; Boumans, L J; van Leeuwen, T C; de Hoop, W D

2001-11-01

238

Clay gouge  

NASA Astrophysics Data System (ADS)

Clays are a common component of fault gouge, but their genesis and importance in fault evolution is poorly understood. We present preliminary evidence that clays participate in extensive mineral reactions and microfabric changes during faulting. Rather than thinking of clay reactions as a consequence of mechanical processes or fault localization following diagenetically altered horizons, we see the interplay between clay mineral reactions and mechanical processes as a single, integrated process. Furthermore, faulting may lower kinetic barriers to low-temperature (˜100°C) mineral reactions that are common in sedimentary rocks. Our most striking example of fault diagenesis-deformation is a profile of %illite in mixed-layer illite/smectite in shales beneath the Lewis Thrust, Canada. Whereas burial diagenesis caused minimal smectite-to-illite reaction, shales within meters of the thrust are almost completely converted to illite. The consequences of these changes are manifested in geochemical, geochronologic and microfabric characteristics of clay gouge. In this example, faulting has helped overcome a kinetic barrier in the smectite-to-illite reaction without appreciable addition of heat. In another example we infer that dissolution-precipitation reactions continue during faulting even when smectite has already been completely transformed to illite. If mineral reactions intimately interact with mechanical processes in shallow-crustal faults, then our current understanding of the mechanical and hydraulic properties of fault zones may be incomplete. Syndeformational mineral reactions and associated fabric changes could make faults much weaker than would be expected from evaluation of the static mineral assemblage of gouge and single crystal properties. Syndeformational mineral reactions may promote fault slip (affecting earthquake activity) in gouge-bearing faults under stress conditions considerably lower than predicted from static mineral properties. In addition, fault-induced dissolution-precipitation reactions may contribute to fault localization.

Vrolijk, Peter; van der Pluijm, Ben A.

1999-08-01

239

Mars, clays and the origins of life  

NASA Technical Reports Server (NTRS)

To detect life in the Martian soil, tests were designed to look for respiration and photosynthesis. Both tests (labeled release, LR, and pyrolytic release, PR) for life in the Martian soils were positive. However, when the measurement for organic molecules in the soil of Mars was made, none were found. The interpretation given is that the inorganic constituents of the soil of Mars were responsible for these observations. The inorganic analysis of the soil was best fitted by a mixture of minerals: 60 to 80 percent clay, iron oxide, quartz, and soluble salts such as halite (NaCl). The minerals most successful in simulating the PR and LR experiments are iron-rich clays. There is a theory that considers clays as the first organisms capable of replication, mutation, and catalysis, and hence of evolving. Clays are formed when liquid water causes the weathering of rocks. The distribution of ions such as aluminum, magnesium, and iron play the role of bases in the DNA. The information was stored in the distribution of ions in the octahedral and tetrahedral molecules, but that they could, like RNA and DNA, replicate. When the clays replicated, each sheet of clay would be a template for a new sheet. The ion substitutions in one clay sheet would give rise to a complementary or similar pattern on the clay synthesized on its surface. It was theorized that it was on the surface of replicating iron-rich clays that carbon dioxide would be fixed in the light into organic acids such as formic or oxalic acid. If Mars had liquid water during a warm period in its past, clay formation would have been abundant. These clays would have replicated and evolved until the liquid water was removed due to cooling of Mars. It is entirely possible that the Viking mission detected life on Mars, but it was clay life that awaits the return of water to continue its evolution into life based on organic molecules.

Hartman, Hyman

1989-01-01

240

Bio-dissolution of colloidal-size clay minerals entrapped in microporous silica gels.  

PubMed

Four colloidal-size fractions of strongly anisotropic particles of nontronite (NAu-2) having different ratios of basal to edge surfaces were incubated in the presence of heterotrophic soil bacteria to evaluate how changes in mineral surface reactivity influence microbial dissolution rate of minerals. To avoid any particle aggregation, which could change the reactive surface area available for dissolution, NAu-2 particles were immobilized in a biocompatible TEOS-derived silica matrix. The resulting hybrid silica gels support bacterial growth with NAu-2 as the sole source of Fe and Mg. Upon incubation of the hybrid material with bacteria, between 0.3% and 7.5% of the total Fe included in the mineral lattice was released with a concomitant pH decrease. For a given pH value, the amount of released Fe varied between strains and was two to twelve-fold higher than under abiotic conditions. This indicates that complexing agents produced by bacteria play an important role in the dissolution process. However, in contrast with proton-promoted NAu-2 dissolution (abiotic incubations) that was negatively correlated with particle size, bacterial-enhanced dissolution was constant for all size fractions used. We conclude that bio-dissolution of nontronite particles under acidic conditions seems to be controlled by bacterial metabolism rather than by the surface reactivity of mineral. PMID:21807370

Grybos, Malgorzata; Billard, Patrick; Desobry-Banon, Sylvie; Michot, Laurent J; Lenain, Jean-François; Mustin, Christian

2011-10-15

241

Effect of iron oxide coatings on zinc sorption mechanisms at the clay-mineral\\/water interface  

Microsoft Academic Search

Oxide surface coatings are ubiquitous in the environment, but their effect on the intrinsic metal uptake mechanism by the underlying mineral surface is poorly understood. In this study, the zinc (Zn) sorption complexes formed at the kaolinite, goethite, and goethite-coated kaolinite surfaces, were systematically studied as a function of pH, aging time, surface loading, and the extent of goethite coating,

Maarten Nachtegaal; Donald L. Sparks

2004-01-01

242

High resolution variability of clay mineral assemblages in the northern South China Sea during the Mid-Pleistocene Transition and its paleoceanographic significance  

NASA Astrophysics Data System (ADS)

Distribution of clay minerals in modern oceans has been widely used to reconstruct paleoclimates. Their distribution is controlled primarily by the rock type and climate in their source regions and by the transport agents and directions. Temporal changes of clay mineral contents in marine sediment cores could therefore provide useful information on both paleoclimates on adjacent lands and past oceanic circulation patterns. The clay-mineral composition of the Mid-Pleistocene Transition sediments (1000~780 ka) at the Ocean Drilling program (ODP) Site 1144 on the northern slope of South China Sea (SCS) consists mainly of smectite (20~60%) and illite (23~45%), with associated chlorite (10~25%) and kaolinite (4~12%). Hydrodynamic and mineralogical studies indicate that illite and chlorite sources were mainly Taiwan and Pearl River, that smectite originated predominantly from the Luzon volcanic arc, and that kaolinite was primarily derived from the Pearl River. Clay mineral assemblages indicate strong glacial-interglacial cyclicity, with high illite, chlorite, and kaolinite contents during glacials and high smectite content during interglacials. The ratio of smectite/(illite+ chlorite+ kaolinite) was adopted as a proxy for the sea level change. Wavelet analysis and filtering of the proxy for the sea level change reveals the filtering signal of 20 kyr precession cycles experienced a decrease after 900 ka. It may suggest that the influence of tropical ocean for the northern SCS has weakened after MPT. Clay mineral results show that the sea level change has undergone a great variation after MPT, and it caused the transportation mechanism of terrigenous particles changing greatly. There are more terrigenous input during glacial periods on the northern slope of SCS as the extent of sea level change increased which result in the strengthening of shelf reworking on northern slope of SCS.

Tuo, S.; Liu, Z.; Colin, C. C.; Jian, Z.; Jin, H.

2012-12-01

243

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

PubMed

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

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

2014-09-25

244

Clay mineral weathering and contaminant dynamics in a caustic aqueous system I. Wet chemistry and aging effects  

SciTech Connect

Caustic high level radioactive waste induces mineral weathering reactions that can influence the fate of radionuclides released in the vicinity of leaking storage tanks. The uptake and release of CsI and SrII were studied in batch reactors of 2:1 layer-type silicates?illite (Il), vermiculite (Vm) and montmorillonite (Mt)?under geochemical conditions characteristic of leaking tank waste at the Hanford Site in WA (0.05 mAlT, 2 m Na*, 1 m NO3 *, pH *14, Cs and Sr present as co-contaminants). Time series (0 to 369 d) experiments were conducted at 298 K, with initial [Cs]0 and [Sr]0 concentrations from 10*5 to 10*3 mol kg*1. Clay mineral type affected the rates of (1) hydroxide promoted dissolution of Si, Al and Fe, (2) precipitation of secondary solids and (3) uptake of Cs and Sr. Initial Si release to solution followed the order Mt * Vm * Il. An abrupt decrease in soluble Si and/or Al after 33 d for Mt and Vm systems, and after 190 d for Il suspensions was concurrent with accumulation of secondary aluminosilicate precipitates. Strontium uptake exceeded that of Cs in both rate and extent, although sorbed Cs was generally more recalcitrant to subsequent desorption and dissolution. After 369 d reaction time, reacted Il, Vm and Mt solids retained up to 17, 47 and 14 mmol kg*1 (0.18, 0.24 and 0.02 *mol m*2) of Cs, and 0, 27 and 22 mmol kg*1 (0, 0.14 and 0.03 *molm*2) Sr, respectively, which were not removed in subsequent Mg exchange or oxalic acid dissolution reactions. Solubility of Al and Si decreased with initial Cs and Sr concentration in Mt and Il, but not in Vm. High co-contaminant sorption to the Vm clay, therefore, appears to diminish the influence of those ions on mineral transformation rates.

Choi, Sunkyung; Amistadi, Mary K.; Chorover, Jon

2005-04-08

245

The Infrared Spectra Study of Dehydrated and Dehydroxylated Clay Samples  

NASA Astrophysics Data System (ADS)

The OMEGA visible and near infrared imaging spectrometer detected phyllosilicates in ancient Noachian terrains of Mars-an observation later confirmed by CRISM imaging spectrometer. Detailed mapping showed that the phyllosilicates, most of which are clay minerals, are found in ancient, heavily cratered terrains. These clay-bearing deposits contain interbedded and buried craters, and it is possible the clay minerals were repeatedly subjected to high temperatures resulting from impact processes. We hypothesize that the dehydration and dehydroxylation of clay minerals subjected to impact was a widespread process on early Mars, and that dehydrated and dehydroxylated clay minerals may be still abundant on the surface of Mars. The objective of this study is to characterize the infrared spectral features of clay minerals when they are heated to increasingly higher temperatures. Using a Nicolet 6700 FTIR spectrometer, we have acquired mid-infrared reflectance (500cm-1-7000cm-1), far-infrared reflectance (60cm-1-500cm-1) and ATR (attenuated total reflectance)(500cm-1-4000cm-1) spectra of 13 clay samples at different temperatures(from 100°C to 900°C). All of the clay samples have been prepared to be very pure (<2?m size fraction) and they were heated for 24 hours at each temperature. The structures of clay minerals are well known because of their typical layer structure and complex relations with water and OH bonds. Our data show that the infrared spectra of clay minerals changed as the temperature increased, which helps us to understand the temperature-related processes including removal of water and OH groups, change of Si-O bond, even the complete destruction of clay layer structures. Differences among dehydration and dehydroxylation conditions for these clay minerals are also discussed in this work. In our future work, we will continue to collect the infrared spectra of more clay minerals and collect additional data for our samples, including VNIR reflectance, XRD, NMR, and emissivity spectra, which can provide insights into the crystal structures and help us to answer the very first question: is it possible that dehydrated and dehydroxylated clay minerals are an explanation for poorly crystalline or amorphous materials on Mars?

Che, C.; Glotch, T.; Cintrón, I.

2008-12-01

246

Clay mineral contribution from various provenances in the northern South China Sea over the past 400 kyr: implications for the East Asian monsoon evolution  

NASA Astrophysics Data System (ADS)

Clay mineralogy of Core MD12-3432 taken at 2125 m water depth (CIRCEA cruise on board the R.V. Marion Dufresne, IPEV) in the northern South China Sea was investigated in order to understand the time series contribution of terrigenous sediments from various provenances. With calibration of a low-resolution analysis on carbonate concentration and major elements, we converted the XRF core scanned calcium data into a high-resolution carbonate content records. Through referring to the well-dated carbonate record of nearby Core MD05-2904, we established a reliable age model, indicating about 400 kyr ago at the bottom of Core MD12-3432. The clay mineral assemblage is dominated by smectite (23-59%) and illite (22-43%), with minor chlorite (13-27%) and kaolinite (4-13%). The time series variation of clay mineral assemblages indicates strong glacial-interglacial cyclicity. In general, the variation in smectite content is similar to that of carbonate concentration, with higher values during interglacials than during glacials, while illite and chlorite contents showing opposite patterns. The change in kaolinite content shows an independent pattern with high values during glacials, corresponding well with the illite crystallinity variation. The provenance analysis of these clay minerals suggests three end-member sources: all smectites derive from Luzon, all kaolinites originate from the Pearl River, and illite and chlorite are coming from both the Pearl River and Taiwan. Using the linear separation method of illite crystallinity, a time series of the clay mineral contribution from the three major provenances to the northern South China Sea was reconstructed. Combined with spectral analyses, we suggest the clay mineral contribution from Pearl River was mainly influenced by sea level change, while the East Asian summer monsoon controlled the contribution from Luzon. The strong precipitation rate related to intensive East Asian summer monsoon would have enhanced the denudation and intensified the delivery of terrigenous materials from Luzon to the South China Sea. Though Taiwan is also suffering from the monsoon rainfall, the major sediment discharge is caused by strong activities like typhoon rather than average precipitation. Thus, the glacial-interglacial variation in the clay mineral contribution from Luzon indicates the East Asian monsoon evolution. This work is presently conducted in the framework of the Franco-Chinese LIA-MONOCL.

Chen, Quan; Liu, Zhifei; Xie, Xin; Kissel, Catherine

2014-05-01

247

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

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, 14?,571) ?g g?¹ and mean Fe concentration in the clay minerals was 2791 (±1782) ?g g?¹. All specimens had Fe concentrations significantly higher (p ? 0.005) than the Fe concentration of WB (77 ?g g?¹). 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

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

2013-08-01

248

Importance of clay size minerals for Fe(III) respiration in a petroleum-contaminated aquifer  

Microsoft Academic Search

The availability of Fe(III)-bearing minerals for dissimilatory Fe(III) reduction was evaluated in sediments from a petroleum-contaminated sandy aquifer near Bemidji, Minnesota (USA). First, the sediments from a contamin- ated area of the aquifer, in which Fe(III) reduction was the predominant terminal electron accepting process, were compared with sediments from a nearby, uncontaminated site. Data from 0.5 M HCl extraction of

Evgenya S. Shelobolina; Robert T. Anderson; Yury N. Vodyanitskii; Anatolii V. Sivtsov; Richard Yuretich; Derek R. Lovley

2004-01-01

249

Clay mineral weathering and contaminant dynamics in a caustic aqueous system  

Microsoft Academic Search

Caustic high level radioactive waste induces mineral weathering reactions that can influence the fate of radionuclides released in the vicinity of leaking storage tanks. The uptake and release of CsI and SrII were studied in batch reactors of 2:1 layer-type silicates—illite (Il), vermiculite (Vm) and montmorillonite (Mt)—under geochemical conditions characteristic of leaking tank waste at the Hanford Site in WA

Sunkyung Choi; Mary Kay Amistadi; Jon Chorover

2005-01-01

250

Clay mineral weathering and contaminant dynamics in a caustic aqueous system  

Microsoft Academic Search

Microscopic and spectroscopic studies were conducted to assess mineral transformation processes in aqueous suspensions of illite (Il), vermiculite (Vm) and montmorillonite (Mt) that were subjected to weathering in a simulated high-level radioactive tank waste leachate (0.05 m AlT, 2 m Na+, 1 m NO3?, pH ?14, Cs+ and Sr2+ present as co-contaminants). Time series (0 to 369 d) experiments were

Sunkyung Choi; Garry Crosson; Karl T. Mueller; Supapan Seraphin; Jon Chorover

2005-01-01

251

Symbiotic nitrogen fixation in eight Acacia senegal provenances in dryland clays of the Blue Nile Sudan estimated by the 15 N natural abundance method  

Microsoft Academic Search

The symbiotic biological N2fixation by Acacia senegal was estimated using the 15N natural abundance (?\\u000a \\u0009\\u0009\\u0009\\u0009\\u0009\\u0009\\u0009\\u000915N) procedure on eight provenances collected from different environments and soil types grown in a clay soil in the Blue Nile\\u000a region, Sudan. Balanites aegyptiaca (a non-legume) was used as a non-N2-fixing reference plant to allow 15N-based estimates of the proportion of the Acacia N

El Amin Yousif Raddad; Ahmed Ali Salih; Mohamed Ahmed El Fadl; Vesa Kaarakka; Olavi Luukkanen

2005-01-01

252

High gradient magnetic separation of iron oxide minerals from soil clays  

E-print Network

. The titanium oxide minerals, anatase and rutile, were identified by peaks at 3. 52A and 3. 25A respectively (Hutton, 1977). In many D 0 cases, the 3. 52A anatase peak could not be resolved from the 3. 57A kaolinite peak until the kaolinite peak... was destroyed by heating at 550'C. The 3. 52A and 3. 25A peaks are the strongest peaks for anatase and rutile and are the only ones normally observed in routine x-ray diffraction analysis. 25 RESULTS AND DISCUSSION Effectiveness of Magnetic Separation...

Schulze, Darrell Gene

2012-06-07

253

Failure of dietary bentonite clay, Silent Herder mineral supplement, or parenteral Banamine to alleviate locoweed toxicosis in rats.  

PubMed

To evaluate treatments purportedly beneficial for livestock grazing locoweeds (LW), growing rats were fed diets containing 10 or 20% whole-plant Oxytropis sericea (LW) with and without Silent Herder mineral mix (1.5% of diet) or bentonite clay (1.5% of diet). Pregnant female rats fed 10% LW were treated i.m. with Banamine (a prostaglandins suppressor) or saline. The LW contained swainsonine (430 micrograms/g DM) and elicited toxicosis within 10 d at intake of 2 mg/kg BW. In Trial 1, 96 immature male Sprague-Dawley rats (BW approximately 100 g) were fed commercial rat feed (CRF) with and without LW, as follows: 100% CRF, free choice; 100% CRF, restricted intake to equal average intake of rats consuming 10 and 20% LW; 90% CRF+10% LW free choice; and 80% CRF+20% LW free choice. Diets with LW contained either no supplement or supplemental mineral mixture (Silent Herder, 1.5% of diet) or added bentonite clay (1.5% of diet). Twelve rats received each of eight dietary regimens through 28 d. Locoweed depressed (P < .05) feed intake and BW gain, increased (P < .05) relative size of liver, kidneys, heart, spleen, and testes, and altered blood serum components (P < .05) indicating toxicosis. Dietary provision of Silent Herder or bentonite failed to benefit rats that ingested approximately 4 or 8 mg of swainsonine/kg BW daily through 28 d. In Trial 2, 68 young adult female Sprague-Dawley rats (approximately 230 g BW) were mated and directly assigned to three diets (100% CRF, free choice, 100% CRF, intake restricted slightly below average intake of diet by rats consuming LW, or 90% CRF+10% LW free choice) and two treatments (i.m. saline or i.m. Banamine at .25 mg/kg BW daily for 10 d) in a 3 x 2 factorial arrangement. Approximately half (31 of 68) of the impregnated rats were killed at d 10, when Banamine was discontinued, but diets were continued until the remaining females gave birth. Ingested LW provided approximately 2 mg swainsonine/kg BW daily and elicited toxicosis in 10 d, but LW failed to affect numbers of live concepti at d 10 (P > .5) or numbers of offspring at parturition (P > .10). Banamine did not alleviate LW toxicosis of dams (P > .10). Provision of Silent Herder or bentonite in the diet or Banamine i.m. had no benefit for rats fed toxic locoweed. PMID:9222844

Dugarte-Stavanja, M; Smith, G S; Edrington, T S; Hallford, D M

1997-07-01

254

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

NASA Astrophysics Data System (ADS)

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.

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

2007-12-01

255

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

PubMed

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

Ghadiri, M; Chrzanowski, W; Rohanizadeh, R

2014-11-01

256

Dynamics of Late Quaternary North African humid periods documented in the clay mineral record of central Aegean Sea sediments  

NASA Astrophysics Data System (ADS)

The ratio between the clay minerals kaolinite and chlorite has been investigated in high resolution in a late Quaternary sediment core from the central Aegean Sea. The record spans the last ca. 105 ka. The kaolinite/chlorite ratio was used to reconstruct the fine-grained aeolian dust influx from the North African deserts, mainly derived from desiccated lake depressions. It therewith can be used as a proxy for wind activity, aridity and vegetation cover in the source area. The data document three major humid phases in North Africa bracketing the formation of sapropel layers S4, S3 and S1. They occur at > 105-95 ka, 83.5-72 ka and 14-2 ka. The first two phases are characterised by relatively abrupt lower and upper boundaries suggesting a non-linear response of vegetation to precipitation, with critical hydrological thresholds. In contrast, the onset and termination of the last humid period were more gradual. Highest kaolinite/chlorite ratios indicating strongest aeolian transport and aridity occur during Marine Isotope Stage (MIS) 5b, at ca. 95-84 ka. The long-term decrease in kaolinite/chlorite ratios during the last glacial period indicates a gradual decline of deflatable lake sediments in the source areas.

Ehrmann, Werner; Seidel, Martin; Schmiedl, Gerhard

2013-08-01

257

Effect of iron oxide coatings on zinc sorption mechanisms at the clay-mineral/water interface.  

PubMed

Oxide surface coatings are ubiquitous in the environment, but their effect on the intrinsic metal uptake mechanism by the underlying mineral surface is poorly understood. In this study, the zinc (Zn) sorption complexes formed at the kaolinite, goethite, and goethite-coated kaolinite surfaces, were systematically studied as a function of pH, aging time, surface loading, and the extent of goethite coating, using extended X-ray absorption fine structure (EXAFS) spectroscopy. At pH 5.0, Zn partitioned to all sorbents by specific chemical binding to hydroxyl surface sites. At pH 7.0, the dominant sorption mechanism changed with reaction time. At the kaolinite surface, Zn was incorporated into a mixed metal Zn-Al layered double hydroxide (LDH). At the goethite surface, Zn initially formed a monodentate inner-sphere adsorption complex, with typical Zn-Fe distances of 3.18 A. However, with increasing reaction time, the major Zn sorption mechanism shifted to the formation of a zinc hydroxide surface precipitate, with characteristic Zn-Zn bond distances of 3.07 A. At the goethite-coated kaolinite surface, Zn initially bonded to FeOH groups of the goethite coating. With increasing aging time however, the inclusion of Zn into a mixed Zn-Al LDH took over as the dominant sorption mechanism. These results suggest that the formation of a precipitate phase at the kaolinite surface is thermodynamically favored over adsorption to the goethite coating. These findings show that the formation of Zn precipitates, similar in structure to brucite, at the pristine kaolinite, goethite, and goethite-coated kaolinite surfaces at near neutral pH and over extended reaction times is an important attenuation mechanism of metal contaminants in the environment. PMID:15219425

Nachtegaal, Maarten; Sparks, Donald L

2004-08-01

258

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

USGS Publications Warehouse

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.

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

2002-01-01

259

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 ...

260

Mineral catalysis of the formation of the phosphodiester bond in aqueous solution: The possible role of montmorillonite clays  

Microsoft Academic Search

The binding of adenosine to Na+-montmorillonite 22A is greater than 5'-AMP, at neutral pH. Adenine derivatives bind more strongly to the clay than the corresponding uracil derivatives. These data are 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. Other forces must be operative

James P. Ferris; Gözen Ertem; Kamaluddin; Vipin Agarwal; Lu Lin Hua

1989-01-01

261

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

Microsoft Academic Search

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

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

1995-01-01

262

Environmental health criteria 231: Bentonite, kaolin, and selected clay minerals (2005) Environmental Health Criteria, (231), pp. i-175.  

E-print Network

is kaolinite; in addition, it frequently contains quartz, mica, feldspar, illite, and montmorillonite are illite and chlorite. Illite is also a component of ball clays. Illite closely resembles micas, but it has, and cosmetics industries. Common clay and shale, of which illite is often a major component, are used mainly

Ahmad, Sajjad

263

CLAY AND SHALE--2001 18.1 CLAY AND SHALE  

E-print Network

with minor to major amounts of illite, chlorite, smectite minerals, quartz, and organic materials. Bentonites. Common clays contain illite and chlorite as major components. Fire clay comprises mainly kaolinite

264

An EXAFS study on the effects of natural organic matter and the expandability of clay minerals on cesium adsorption and mobility  

NASA Astrophysics Data System (ADS)

The relationship between cesium (Cs) adsorption on clay minerals with various expandabilities and Cs mobility in environment was investigated using sequential extraction, batch adsorption, X-ray diffraction (XRD), generalized adsorption model (GAM), and Cs LIII-edge extended X-ray absorption fine structure (EXAFS) analyses with molecular simulations using the density functional theory (DFT). In particular, the difference between the affinities of illite (non-expansion) and vermiculite (intermediate expansion) for Cs and the effect of humic acid (HA) addition on the Cs/clay mineral system were highlighted in this study. These two factors affect Cs mobility and bioavailability in surface soil and sediments. The batch adsorption results showed that Cs adsorption was inhibited to some extent in the ternary clay + HA + Cs system because of (i) the blocked access of Cs to the frayed edge site (FES) and type II site [inner-sphere (IS) complex in GAM] by HA, and (ii) the reduced availability of the interlayer site in vermiculite. EXAFS analysis further confirmed that the adsorbed Cs in clay minerals was drastically changed by the sequential addition of HA. In addition, the dominant IS complex in the illite + Cs and illite + Cs + HA systems (in which HA was added after Cs adsorption on illite) can be converted to the outer-sphere (OS) complex largely in the illite + HA + Cs system (in which HA was added prior to Cs adsorption). These results are consistent with the sequential extraction and GAM results. The IS complex of dehydrated Cs+ mainly formed at the FES and interlayer site on illite (non-expansion) without resulting in any illite structural changes. However, on vermiculite (intermediate expansion), the dehydrated Cs+ can be adsorbed as an IS complex associated with the siloxane group of the di-trigonal cavity in the tetrahedral SiO4 sheet. This adsorption is accompanied by collapse of the layer, which can be easily coated by HA molecules to prevent Cs fixation. However, a nearly complete OS complex was observed at the planar site of montmorillonite (large expansion). These processes were confirmed by sequential extraction, batch adsorption, XRD, and EXAFS, which clearly showed that Cs mobility in soil highly depends on clay mineral expandability, natural organic matter (NOM), and the coupling of both effects. The atomic-scale information given by EXAFS is consistent with the distribution data from adsorption experiments, GAM, sequential extraction, and DFT. These results can be used as a basis for a clearer understanding of Cs behavior in natural systems.

Fan, Q. H.; Tanaka, M.; Tanaka, K.; Sakaguchi, A.; Takahashi, Y.

2014-06-01

265

Biodegradation and adsorption of C1- and C2-phenanthrenes and C1- and C2-dibenzothiophenes in the presence of clay minerals: effect on forensic diagnostic ratios.  

PubMed

The impact of modified montmorillonites on adsorption and biodegradation of crude oil C1-phenanthrenes, C1-dibenzothiophenes, C2-phenanthrenes and C2-dibenzothiophenes was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. Consequently, the effect on C1-dibenzothiophenes/C1-phenanthrenes, C2-dibenzothiophenes/C2-phenanthrenes, 2+3-methyldibenzothiophene/4-methyldibenzothiophene and 1-methyldibenzothiophene/4-methyldibenzothiophene ratios commonly used as diagnostic ratios for oil forensic studies was evaluated. The clay mineral samples were treated to produce acid activated montmorillonite, organomontmorillonite and homoionic montmorillonite which were used in this study. The different clay minerals (modified and unmodified) showed varied degrees of biodegradation and adsorption of the C1-phenanthrenes, C1-dibenzothiophenes, C2-phenanthrenes and C2-dibenzothiophenes. The study indicated that as opposed to biodegradation, adsorption has no effect on the diagnostic ratios. Among the diagnostic ratios reviewed, only C2-dibenzothiophenes/C2-phenanthrenes ratio was neither affected by adsorption nor biodegradation making this ratio very useful in forensic studies of oil spills and oil-oil correlation. PMID:24275986

Ugochukwu, Uzochukwu C; Head, Ian M; Manning, David A C

2014-07-01

266

Diagenesis of clay minerals and K-bentonites in Late Permian/Early Triassic sediments of the Sichuan Basin (Chaotian section, Central China)  

NASA Astrophysics Data System (ADS)

Detailed clay mineralogical analyses were carried out on Late Permian/Early Triassic carbonate sediments exposed on the Chaotian section (Sichuan Basin, Central China). The clay assemblages are dominantly composed of illite in platform carbonates and clay seams, and illite-smectite mixed-layers (I/S) in tuff layers (K-bentonites) intercalated in the carbonate succession. Detrital and authigenic volcanogenic clay minerals have been partially replaced through illitisation processes during burial, raising questions about diagenetic effects. The precise determination of I/S occurring in K-bentonites shows that the sediments reached a temperature of about 180 °C, which is consistent with (1) previous estimates based on fluid-inclusion homogenisation temperature analysis, (2) the burial depth of the sedimentary series deduced from the post-Palaeozoic geological history of the Sichuan Basin and (3) the new data (Tmax) obtained on organic matter indicating the transition between oil and gas windows. The Wangpo Bed, located close to the Guadalupian-Lopingian Boundary, is interpreted either as a volcanic acidic tuff or as a clastic horizon. This controversial origin probably results from mixed volcanogenic and detrital influences. The Wangpo Bed is therefore interpreted as a reworked bentonite as revealed by the occurrence of I/S similar to those found in tuff layers, together with preserved detrital kaolinite.

Deconinck, J. F.; Crasquin, S.; Bruneau, L.; Pellenard, P.; Baudin, F.; Feng, Q.

2014-02-01

267

The role of clay minerals and fulvic acid to the complexation of Na, Mg, and Ca in stream flows from adjacent forested head watersheds composed of different vegetation  

NASA Astrophysics Data System (ADS)

In order to understand the complexation and flow process in metal elements under a fresh water environment, discharges of Na, Mg, and Ca were measured in streams of adjacent forested head watersheds composed of coniferous evergreen- and deciduous broad leaf- trees. Total elements (T-Na, T-Mg, and T-Ca) and ions (Na+, Mg2+, and Ca2+) in stream flows which passed through 0.45 ?m filters were measured with an ICP and Ion-chromatograph. The remainders of total elements and ions were equated with complex compounds. Then the discharges of Si and fulvic acid, which respectively are the representatives of ligands by clay minerals and humic substances, provided the relationship between the compound discharges and the complexation process of the above metal elements. Even if Na, Mg, and Ca are believed to be mostly free ions in fresh water environments, the rates of the compounds to the total elements ranged 10 to 40 % in the coniferous watershed and 20 to 60 % in the deciduous watersheds. The compounds sometimes occupied more than half of the total elements; this was predominant in the deciduous watershed. These mean that the discharge of compounds is not negligible in watershed hydrology. Possible complexation processes in metal elements are #1) Hydration, #2) Adsorption or substitution with clay minerals, #3) Mineral complex, #4) Adsorption with humic substances as represented by fulvic acid, and #5) Chelate with organic acids as oxalate, formic acid, and pyrrole. Under fresh water environments, #2 and #4 must be the most potential processes of the complexation in metal elements. The relationship between the compounds, Si, and fulvic acid, therefore, supplies useful information to presume the status of the compounds. The compounds-Si relations in both watersheds showed linear correlations (r=0.79 to 0.99) for a stream base flow and stream flow in a small rainstorm. The linear correlations, however, occurred only for the stream flow in the compounds-Si relations at a big rain storm in the deciduous watershed (r=0.89 to 1.00) and also for the storm flow in the compound-fulvic acid relations (r=0.95 to 0.99). These things mean that the metal elements possibly flowed out as organic and/or inorganic complexes and the complexation could have been promoted in the deciduous watershed during rain storms. Thick organic soil, broadly distributing in the deciduous watershed, seems to be reasonable for promoting such complexation due to subsurface water movement in the soil through the contact of the metal elements with clay minerals and fulvic acid. In contrast, the much rainwater flows down below the surface within the loose litter and root-permeated zone developing predominantly in the coniferous watershed, where small clay minerals and humic substances occurs; which represents the rare contact of the metal elements with the clay minerals and fulvic acid in such flow paths. This would be the reason for the small and restrained complexation in the coniferous watershed at the big rain storm. The hydrochemical process in slope-stream systems can be controlled by the complexation affected by both the flow path of rainwater and the distribution of clay minerals and humic substances in soils.

Terajima, Tomomi; Moriizumi, Mihoko; Nakamura, Tomohiro

2010-05-01

268

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)  

NASA Astrophysics Data System (ADS)

A detailed mineralogical study is presented of the matrix of mudrocks sampled from spot coring at three key locations along the San Andreas Fault Observatory at depth (SAFOD) drill hole. The characteristics of authigenic illite-smectite (I-S) and chlorite-smectite (C-S) mixed-layer mineral clays indicate a deep diagenetic origin. A randomly ordered I-S mineral with ca. 20-25% smectite layers is one of the dominant authigenic clay species across the San Andreas Fault zone (sampled at 3,066 and 3,436 m measured depths/MD), whereas an authigenic illite with ca. 2-5% smectite layers is the dominant phase beneath the fault (sampled at 3,992 m MD). The most smectite-rich mixed-layered assemblage with the highest water content occurs in the actively deforming creep zone at ca. 3,300-3,353 m (true vertical depth of ca. 2.7 km), with I-S (70:30) and C-S (50:50). The matrix of all mudrock samples show extensive quartz and feldspar (both plagioclase and K-feldspar) dissolution associated with the crystallization of pore-filling clay minerals. However, the effect of rock deformation in the matrix appears only minor, with weak flattening fabrics defined largely by kinked and fractured mica grains. Adopting available kinetic models for the crystallization of I-S in burial sedimentary environments and the current borehole depths and thermal structure, the conditions and timing of I-S growth can be evaluated. Assuming a typical K+ concentration of 100-200 ppm for sedimentary brines, a present-day geothermal gradient of 35°C/km and a borehole temperature of ca. 112°C for the sampled depths, most of the I-S minerals can be predicted to have formed over the last 4-11 Ma and are probably still in equilibrium with circulating fluids. The exception to this simple burial pattern is the occurrence of the mixed layered phases with higher smectite content than predicted by the burial model. These minerals, which characterize the actively creeping section of the fault and local thin film clay coating on polished brittle slip surfaces, can be explained by the influence of either cooler fluids circulating along this segment of the fault or the flow of K+-depleted brines.

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

2009-02-01

269

Characterization and quantification of Sm(III)/ and Cm(III)/clay mineral outer-sphere species by TRLFS in D2O and EXAFS studies.  

PubMed

In order to assess the long-term safety of deep radioactive waste repositories, a precise characterization of the different sorption processes on a molecular basis and the exact definition of geochemical boundary conditions for their relevance are of immense importance. Through sorption on various minerals the migration of radionuclides will be hindered and their retention will be ensured. Using time-resolved laser fluorescence spectroscopy (TRLFS) and extended X-ray absorption fine structure (EXAFS) spectroscopy, it was possible to identify outer-sphere sorbed trivalent lanthanides and actinides onto different montmorillonites and illite. Furthermore, the quantification of Cm(III)/clay outer-sphere sorption in D(2)O at different ionic strengths was shown. The results were confirmed by ion exchange model calculations. Finally, the structural parameters of a Sm(III)/clay outer-sphere complex were obtained by EXAFS measurements. PMID:21030033

Hartmann, Eva; Brendebach, Boris; Polly, Robert; Geckeis, Horst; Stumpf, Thorsten

2011-01-15

270

ABUNDANCE OF TRACE AND MINOR ELEMENTS IN ORGANIC AND MINERAL FRACTIONS OF COAL  

EPA Science Inventory

The report gives results of subjecting 27 U.S. coals to float/sink, acid, and ion-exchange treatments. From these treatments, coal fractions were obtained and analyzed to determine the organic and mineral associations of 45 elements. Of the elements studied, B, Be, Br, Ge, and Sb...

271

Water adsorption on clay minerals as a function of relative humidity: application of BET and Freundlich adsorption models.  

PubMed

Water adsorption on kaolinite, illite, and montmorillonite clays was studied as a function of relative humidity (RH) at room temperature (298 K) using horizontal attenuated total reflectance (HATR) Fourier transform infrared (FTIR) spectroscopy equipped with a flow cell. The water content as a function of RH was modeled using the Brunauer, Emmett, and Teller (BET) and Freundlich adsorption isotherm models to provide complementary multilayer adsorption analysis of water uptake on the clays. A detailed analysis of model fit integrity is reported. From the BET fit to the experimental data, the water content on each of the three clays at monolayer (ML) water coverage was determined and found to agree with previously reported gravimetric data. However, BET analysis failed to adequately describe adsorption phenomena at RH values greater than 80%, 50%, and 70% RH for kaolinite, illite, and montmorillonite clays, respectively. The Freundlich adsorption model was found to fit the data well over the entire range of RH values studied and revealed two distinct water adsorption regimes. Data obtained from the Freundlich model showed that montmorillonite has the highest water adsorption strength and highest adsorption capacity at RH values greater than 19% (i.e., above ML water adsorption) relative to the kaolinite and illite clays. The difference in the observed water adsorption behavior between the three clays was attributed to different water uptake mechanisms based on a distribution of available adsorption sites. It is suggested that different properties drive water adsorption under different adsorption regimes resulting in the broad variability of water uptake mechanisms. PMID:22181675

Hatch, Courtney D; Wiese, Jadon S; Crane, Cameron C; Harris, Kenneth J; Kloss, Hannah G; Baltrusaitis, Jonas

2012-01-24

272

Discoloration and mineralization of Orange II by using Fe 3+-doped TiO 2 and bentonite clay-based Fe nanocatalysts  

Microsoft Academic Search

Nanostructured catalysts (Fe3+-doped TiO2 and bentonite clay-based Fe nanocomposite (Fe–B)) have been developed for the discoloration and mineralization of a non-biodegradable azo dye, Orange II. The Fe3+-doped TiO2 nanocatalysts synthesized by the sol–gel method and the Fe–B nanocatalyst by the pillaring method were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray reflective fluorescence (XRF), and the BET method.

Jiyun Feng; Raymond S. K. Wong; Xijun Hu; Po Lock Yue

2004-01-01

273

Comparative 40Ar/39Ar and K-Ar dating of illite-type clay minerals: A tentative explanation for age identities and differences  

NASA Astrophysics Data System (ADS)

The 40K/40Ar (K-Ar) and 40Ar/39Ar dating methods are applied here to the same, very small, micrometric illite-type particles that crystallized under low-temperature (< 175 °C) hydrothermal conditions in deeply buried Rotliegend (Permian) gas-bearing sandstones of NW Germany. Four samples with a total of fifteen size fractions from < 2 to 20-40 ?m yield K-Ar ages that range from 166.0 ± 3.4 to 214.0 ± 5.9 Ma. The same size fractions dated by the 40Ar/39Ar method give total-gas ages ranging from 173.3 ± 2.0 to 228.8 ± 1.6 Ma. Nearly all 40Ar/39Ar total-gas ages are slightly older, which cannot be explained by the recoil effect only, the impact of which being amplified by the inhomogeneous shape of the clay minerals and their crystallographic characteristics, with varied crystallinity indices, and a particle width about 10 times large than thickness. The 40Ar/39Ar data outline some advantages, such as the plateaus obtained by incremental step heating of the various size fractions, even if not translatable straight as ages of the illite populations; they allow identification of two generations of authigenic illite that formed at about 200 and 175 Ma, and one detrital generation. However, 40Ar/39Ar dating of clay minerals remains challenging as technical factors, such as the non-standardized encapsulation, may have potential unexpected effects. Both dating methods have their limitations: (1) K-Ar dating requires relatively large samples (ca. 10-20 mg) incurring potential sample homogeneity problems, with two aliquots required for K and Ar analysis for an age determination, also inducing a higher analytical uncertainty; (2) an identified drawback of 40Ar/39Ar dating is Ar recoil and therefore potential loss that occurs during neutronic creation of 39Ar from 39K, mostly in the finer mineral particles. If all the recoiled 39Ar is redistributed into adjacent grains/minerals, the final 40Ar/39Ar age of the analyzed size fraction remains theoretically identical, but it is not systematic in clay-type material. The finest grain sizes (e.g., < 0.2 ?m) are usually least contaminated with detrital components and can be dated by the K-Ar method without special preparation. Alternatively, such fine fractions are most susceptible to 39Ar recoil, and are, therefore, only datable by the 40Ar/39Ar method using an encapsulation technique that still needs to be technically evaluated. In this study, 39Ar recoil during irradiation was quantified by encapsulation; it ranged from about 20% of the total 39Ar for the < 0.2 ?m fractions to ca. 10% for the 2-6 ?m fractions. Basic interpolation of this 39Ar recoil confirms that grain size increasing minimizes the recoil effect, but how it proceeds has still to be explained. Despite recent developments in 40Ar/39Ar dating, the conventional K-Ar method is still a valuable tool for clay dating due to a convenient and straightforward use supported by a standardized and well-controlled technical approach. The present comparison of the two Ar-dating methods as applied to clay material shows that neither method is presently outdated, and that they are even of reciprocal use. Both methods have distinct application fields in clay geochronology and complementary application fields in clay crystallography.

Clauer, Norbert; Zwingmann, Horst; Liewig, Nicole; Wendling, Raymond

2012-10-01

274

Evolution of clay mineral assemblages in the Tinguiririca geothermal field, Andean Cordillera of central Chile: an XRD and HRTEM-AEM study  

NASA Astrophysics Data System (ADS)

HRTEM textural evidence shows that clay minerals in the Tinguiririca geothermal field (Andean Cordillera, central Chile) are the result of direct alteration of former volcanic glass and minerals by hydrothermal fluids at similar temperatures to the present day. They show the classical pattern of diagenetic transformation from smectite at the top to illite at the bottom, with the progressive formation of corrensite and chlorite. The high fluid/rock ratio, disposability of necessary cations and absence of previous detrital phyllosilicates allow the consideration of this area as a natural laboratory to establish the extreme ideal conditions for very low-T reactions. Transformations from smectite to R1 illite-smectite (I-S) and from these to R3 mixed-layers occur respectively at 80-120 °C and 125-180 °C. In spite of ideal genetic conditions, the new-formed minerals show all the defective character and lack of textural and chemical equilibrium previously described in the literature for diagenetic and hydrothermal low-temperature assemblages. Chemistry of smectite-illite phases evolves basically through a diminution of the pyrophyllitic component toward a theoretical muscovite (Si4 + + ? -> Al3 ++ K+). However, a second chemical vector (Si4 ++ Mg2 + ? Al3 ++ Al3 +), that is, decreasing of the tschermack component, also contributes to the evolution toward the less Si-more Al rich muscovite in relation to the original smectite. Residual Mg (and Fe) from the latter reaction is consumed in the genesis of chloritic phases. Nevertheless, as a consequence of the lack of chemical equilibrium (probably because of the short time-scale of the geothermal alteration processes), the composition of clay minerals is highly heterogeneous at the level of a single sample. Consequently, the respective fields of smectite, R1 I-S and R3 I-S overlap each other, making the distinction among these three phases impossible based exclusively on chemical data.

Vázquez, M.; Nieto, F.; Morata, D.; Droguett, B.; Carrillo-Rosua, F. J.; Morales, S.

2014-08-01

275

Mineral catalysis of the formation of the phosphodiester bond in aqueous solution: the possible role of montmorillonite clays.  

PubMed

The binding of adenosine to Na(+)-montmorillonite 22A is greater than 5'-AMP, at neutral pH. Adenine derivatives bind more strongly to the clay than the corresponding uracil derivatives. These data are 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. Other forces must be operative in the binding of uracil derivatives to the clay since the uracil ring system is not basic. The reaction of the 5'-AMP with water soluble carbodiimide in the presence of Na(+)-montmorillonite results in the formation of 2',5'-pApA (18.9%), 3',5'-pApA (11%), and AppA (4.8%). When poly(U) is used in place of the clay the product yields are 2',5'-pApA (15.5%), 3',5'-pApA (3.7%) and AppA (14.9%). The cyclic nucleotide, c(pA)2 is also formed when poly(U) is used. AppA is the principal reaction product when neither clay nor poly(U) is present in the reaction mixture. When 2'-deoxy-5'-AMP reacts with carbodiimide in the presence of Na(+)-montmorillonite 22A the products are dpApA (4.8%), dAppApA (4.5%) and dAppA (17.4%). Cyclic 3',5'-dAMP is the main product (14%) of the reaction of 2'-deoxy-3'-AMP. PMID:11537376

Ferris, J P; Ertem, G; Kamaluddin; Agarwal, V; Hua, L L

1989-01-01

276

Common clay and shale  

USGS Publications Warehouse

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.

Virta, R.L.

2004-01-01

277

Common clay and shale  

USGS Publications Warehouse

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.

Virta, R.L.

2003-01-01

278

Intercalated clay catalysts  

Microsoft Academic Search

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

T. J. Pinnavaia

1983-01-01

279

Surface Area of Homoionic Illite and Montmorillonite Clay Minerals as Measured by the Sorption of Nitrogen and Carbon Dioxide  

Microsoft Academic Search

The surface areas obtained by application of the B.E.T. theory to adsorption isotherms of nitrogen and carbon dioxide gases at 77~ and 195~ respectively on homoionic samples of illite and montmorillonite clays have been examined. The isotherms were obtained using a standard volumetric adsorption system and the results are compared with those obtained by Thomas and Bohor (1968) using a

L. A. G. Aylmore; I. D. SILLS; J. P. QUIRK

1970-01-01

280

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

E-print Network

in montmorillonite/cement matrices by one unit when clay:cement ratios exceed 0.5. Pozzolanic reactions are nearly complete within 32 days. However, a slow, ancillary reaction, possibly sorption of hydroxide ions onto low calcium:silicon ratio calcium silicate...

Cook, Evan Russell

2012-06-07

281

Minerals  

NSDL National Science Digital Library

This interactive lesson on minerals starts with a definition of minerals and compares crystalline and amorphous minerals. The composition is discussed and a chart shows the relative amounts of elements in minerals. Next, there is a discussion of the characteristics by which minerals are identified including luster, color, streak, hardness, and cleavage and fracture along with special properties such as magnetism. The characteristics of calcite, talc, hematite, magnetite, and galena are then observed.

282

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)

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.

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

2010-12-01

283

Comment on "Evaluation of X-ray diffraction methods for determining the crystal growth mechanisms of clay minerals in mudstones, shales and slates," by L. N. Warr and D. R. Peacor  

USGS Publications Warehouse

A recent paper by Warr and Peacor (2002) suggested that our use of the Bertaut-Warren-Averbach technique (MudMaster computer program) for studying changes in crystallite thickness distributions (CTDs) of clay minerals during diagenesis and very low-grade metamorphism is not reliable because it is dependent on many variables which can not be fully controlled. Furthermore, the authors implied that the measured shapes of CTDs cannot be used with confidence to deduce crystal growth mechanisms and histories for clays, based on our CTD simulation approach (using the Galoper computer program). We disagree with both points, and show that the techniques are powerful, reliable and useful for studying clay mineral alteration in rocks. ?? 2003 Schweiz. Mineral. Petrogr. Ges.

Eberl, D. D.; Srodon, J.; Drits, V. A.

2003-01-01

284

Common clay and shale  

USGS Publications Warehouse

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.

Virta, R.L.

2000-01-01

285

Prospecting for clay minerals within volcanic successions: Application of electrical resistivity tomography to characterise bentonite deposits in northern Sardinia (Italy)  

NASA Astrophysics Data System (ADS)

Electrical resistivity tomography (ERT) is applied to prospect for and characterise a bentonitic clay deposit in northern Sardinia. Sardinian bentonites derived from the hydrothermal alteration of thick successions of pyroclastic flows and epiclastites are associated with the Oligo-Miocene calc-alkaline volcanic cycle. The alteration of these rocks is generally controlled by faults that control the local circulation of hydrothermal fluids. Two-dimensional ERT investigations were performed close to a faulted area to define the location, thickness and lateral continuity of the clayey body, and determine how it relates to faulting and stratigraphy. A line-based three-dimensional ERT data acquisition was carried out in a selected area to estimate the available clay reserves. The reliability of these resistivity models was assessed by comparison with local borehole data. Finally, the interpretation of the ERT results was optimised through synthetic modelling of the electrical resistivity imaging technique. The results define the extent and geometry of the bentonitic deposit with good accuracy and outline the scenarios where the ERT method may provide optimal results when prospecting for clay deposits.

Longo, V.; Testone, V.; Oggiano, G.; Testa, A.

2014-12-01

286

Minerals  

NSDL National Science Digital Library

This page is from James Madison University's Department of Geology and Environmental Science. It provides an introduction to minerals, an alphabetical list of minerals and dichotomous keys to identifying minerals in PDF. There are also links to other department pages on igneous, sedimentary, and metamorphic rocks.

Fichter, Lynn S.

2000-09-13

287

Minerals  

NSDL National Science Digital Library

This slide show provides students with basic information on mineralogy. It explains how the term "mineral" is defined, the properties that are used to identify minerals, their importance in daily life, and some general facts. For each identifying property, an example mineral and photograph are provided. Addresses to websites with additional information are also included.

Passow, Michael

288

Minerals  

NSDL National Science Digital Library

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 ...

Walls, Mrs.

2011-01-30

289

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)

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.

Müller, Claudia; Stein, Ruediger

2000-08-01

290

Simulation of Clay Mineral Dehydration Along the NanTroSEIZE Transect, SW Japan: Implications for Fault Properties and Fluid Flow  

NASA Astrophysics Data System (ADS)

At subduction zones, fluids are expelled as porous sediments on the incoming oceanic plate are either subducted or offscraped and accreted. In the upper ~8-10 km, the dominant sources of fluid are tectonically-driven compaction and burial, and the dehydration of hydrous (smectite family) clays. Potentially elevated pore fluid pressure associated with fluid release has been invoked to explain: (1) zones of anomalously low seismic velocity in the outer forearc (LVZ's) located ~13-30 km and ~31-55 km from the trench; (2) high amplitude negative polarity seismic reflectors along major fault zones; and (3) a transition to unstable fault slip. Here, we incorporate the results of existing thermal modeling and Integrated Ocean Drilling Program (IODP) drilling along the NanTroSEIZE transect, offshore SW Japan, to simulate the magnitude and distribution of fluid release from clay dehydration in 2-D. The thermal models define the temperature structure of the margin, and the drilling results provide constraints on the abundance of hydrous clays in the sediment inputs. The regionally averaged wedge geometry and incoming sediment thickness used in our model are defined from seismic reflection data. We simulate smectite transformation by tracking sediments as they are progressively buried and heated in the subduction complex. The reaction progress is then computed from temperatures and exposure time. We evaluate two thermal models: a "hot" scenario, which is consistent with surface heat flow data, and a "cold" scenario that provides a probable lower bound on subsurface temperatures. For our initial suite of simulations, we consider an average bulk smectite abundance of 45 wt%. We then explore the spatial relationships between the locus of clay dehydration and geophysical signatures interpreted to reflect pore fluid and dehydration processes. Finally, we track the evolution of residual pore fluid chemistry due to consolidation and introduction of fresh water from the dehydration reaction. Simulated peak clay dehydration occurs 8-10 km landward of the trench in the hot scenario, and ~17-20 km landward in the cold scenario, well updip of the high reflectivity fault zones and LVZ's. Within the underthrusting sediments, the simulated reaction is 80% complete by ~15 km and ~25 km landward of the trench for the hot and cold scenarios, respectively. Our results indicate that that the geophysical observations do not map the locus of dehydration. We suggest that compaction disequilibrium is a more plausible explanation for both the high reflectivity and LVZ's. Simulated pore water freshening in the upper wedge is negligible in the outer 26 km of the forearc, and reaches a maximum of ~17% by 75 km landward of the trench. In contrast, simulated pore water freshening in the lower wedge and underthrust sediment begins within ~5-8 km of the trench, and reaches ~65% by 30 km landward. Near the trench, deeply sourced fluids will be diluted by mixing with fluids from the hanging wall. Progressive freshening of the deeply sourced fluids, in combination with decreasing compactive sources in the wedge, should lead to less mixing and thus larger signals of deeply sourced fluid flow farther landward.

Saffer, D. M.; Harris, R. N.; Underwood, M.

2012-12-01

291

Ball clay  

USGS Publications Warehouse

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.

Robert L Virta

2010-01-01

292

Infrared spectroscopic studies of the effect of elevated temperature on the association of pyroglutamic acid with clay and other minerals  

NASA Technical Reports Server (NTRS)

Fourier transform i.r. measurements of L-pyroglutamic acid dispersed in a matrix of a clay, silica or alumina have been obtained at various temperatures between 25 and 220 degrees C. The i.r. spectrum of L-pyroglutamic acid varies in a manner dependent upon the matrix material and shows considerable change as the temperature of the mixtures is increased. The differences in the spectrum at elevated temperatures are explained in terms of a chemical reaction between hydroxyl groups in the matrix and the carboxylic acid. The i.r. spectra of trimethylsilyl derivatives of L-pyroglutamic acid and aluminum pyroglutamate were also measured to assist the understanding of spectra and interpretation of the spectral changes dependent upon increasing temperature.

Macklin, J. W.; White, D. H.

1985-01-01

293

Discharge of landfill leachate to streambed sediments impacts the mineralization potential of phenoxy acid herbicides depending on the initial abundance of tfdA gene classes.  

PubMed

To understand the role of abundance of tfdA gene classes belonging to ?- and ?-proteobacteria on phenoxy acid herbicide degradation, streambed sediments were sampled around three seepage meters (SMs) installed in a landfill-impacted groundwater-surface water interface. Highest herbicide mass discharge to SM3, and lower herbicide mass discharges to SM1 and SM2 were determined due to groundwater discharge rates and herbicide concentrations. SM1-sediment with the lowest abundance of tfdA gene classes had the slowest mineralization, whereas SM2- and SM3-sediments with more abundant tfdA genes had faster mineralization. The observed difference in mineralization rates between discharge zones was simulated by a Monod-based kinetic model, which confirmed the role of abundance of tfdA gene classes. This study suggests presence of specific degraders adapted to slow growth rate and high yield strategy due to long-term herbicide exposure; and thus groundwater-surface water interface could act as a natural biological filter and protect stream water quality. PMID:23454590

Bat?o?lu-Pazarba??, Meriç; Milosevic, Nemanja; Malaguerra, Flavio; Binning, Philip J; Albrechtsen, Hans-Jørgen; Bjerg, Poul L; Aamand, Jens

2013-05-01

294

Clay mineralogy and its effect on physical properties in the Gulf of Mexico northwestern continental slope  

E-print Network

The clay mineral composition of sediments deposited in the last six oxygen isotope stages in the Gulf of Mexico continental slope was characterized. Smectite and illite were found to be the two major clay minerals of the clay fraction while...

Berti, Debora

2005-02-17

295

Ball clay  

USGS Publications Warehouse

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.

Virta, R. L.

2006-01-01

296

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)

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.

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

297

Constraints on Mineral-Phase Abundances and Compositions in the Low-Albedo Northern Plains of Mars using MGS-TES, OMEGA, and Laboratory Spectral Data  

Microsoft Academic Search

The abundances and compositions of mineral-phases in the low-albedo northern plains of Mars have been a focus of considerable study and debate in recent years. Large expanses of Acidalia Planitia surface materials are characterized by the MGS-TES Surface Type 2 (ST2) spectral endmember [1]. The ST2 spectrum is distinguished by a rounded, slightly V-shaped 800 to 1200 wavenumber region of

M. B. Wyatt; J. F. Mustard

2006-01-01

298

Clay Play  

ERIC Educational Resources Information Center

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…

Rogers, Liz; Steffan, Dana

2009-01-01

299

Clay Exploration  

NSDL National Science Digital Library

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.

Museum, Chicago C.

2008-01-01

300

CLAY AND SHALE--2002 18.1 CLAY AND SHALE  

E-print Network

primarily of kaolinite with minor to major amounts of illite, chlorite, smectite minerals, quartz of feldspars, biotite, and quartz. Common clay and shale contain illite and chlorite as major components. Fire

301

Ball clay  

USGS Publications Warehouse

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.

Virta, R. L.

2011-01-01

302

Octachlorodibenzodioxin formation on Fe(III)-montmorillonite clay.  

PubMed

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

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

2008-07-01

303

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

SciTech Connect

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.

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

2000-06-01

304

21 CFR 186.1256 - Clay (kaolin).  

Code of Federal Regulations, 2013 CFR

...powder. There are at least three different minerals, kaolinite, dickite, and nacrite, classified as kaolin. Kaolinite or china clay is whiter, less contaminated with extraneous minerals, and less plastic in water. (b) In accordance...

2013-04-01

305

21 CFR 186.1256 - Clay (kaolin).  

...powder. There are at least three different minerals, kaolinite, dickite, and nacrite, classified as kaolin. Kaolinite or china clay is whiter, less contaminated with extraneous minerals, and less plastic in water. (b) In accordance...

2014-04-01

306

21 CFR 186.1256 - Clay (kaolin).  

Code of Federal Regulations, 2012 CFR

...powder. There are at least three different minerals, kaolinite, dickite, and nacrite, classified as kaolin. Kaolinite or china clay is whiter, less contaminated with extraneous minerals, and less plastic in water. (b) In accordance...

2012-04-01

307

21 CFR 186.1256 - Clay (kaolin).  

Code of Federal Regulations, 2010 CFR

...powder. There are at least three different minerals, kaolinite, dickite, and nacrite, classified as kaolin. Kaolinite or china clay is whiter, less contaminated with extraneous minerals, and less plastic in water. (b) In accordance...

2010-04-01

308

Common clay and shale  

USGS Publications Warehouse

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.

Virta, R.L.

2001-01-01

309

Abundances and distribution of minerals and elements in high-alumina coal fly ash from the Jungar Power Plant, Inner Mongolia, China  

USGS Publications Warehouse

The fly ash from the Jungar Power Plant, Inner Mongolia, China, is unique because it is highly enriched in alumina (Al2O3>50%). The fly ash mainly consists of amorphous glass and mullite and trace amounts of corundum, quartz, char, calcite, K-feldspar, clay minerals, and Fe-bearing minerals. The mullite content in fly ash is as high as 37.4% because of high boehmite and kaolinite contents in feed coal. Corundum is a characteristic mineral formed during the combustion of boehmite-rich coal.Samples from the economizer were sieved into six size fractions (<120, 120-160, 160-300, 300-360, 360-500, and >500 mesh) and separated into magnetic, mullite+corundum+quartz (MCQ) and glass phases for mineralogical and chemical analysis. The corundum content increases but amorphous glass decreases with decreasing particle size. Fractions of small particle sizes are relatively high in mullite, probably because mullite was formed from fine clay mineral particles under high-temperature combustion condition. Similarly, fine corundum crystals formed in the boiler from boehmite in feed coal. The magnetic phase consists of hematite, magnetite, magnesioferrite, and MgFeAlO4 crystals. The MCQ phase is composed of 89% mullite, 6.1% corundum, 4.5% quartz, and 0.5% K-feldspar.Overall, the fly ash from the power plant is significantly enriched in Al2O3 with an average of 51.9%, but poor in SiO2, Fe2O3, CaO, MgO, Na2O, P2O5, and As. Arsenic, TiO2, Th, Al2O3, Bi, La, Ga, Ni, and V are high in mullite, and the magnetic matter is enriched in Fe2O3, CaO, MnO, TiO2, Cs, Co, As, Cd, Ba, Ni, Sb, MgO, Zn, and V. The remaining elements are high in the glass fraction. The concentration of K2O, Na2O, P2O5, Nb, Cr, Ta, U, W, Rb, and Ni do not clearly vary with particle size, while SiO2 and Hg decrease and the remaining elements clearly increase with decreasing particle size. ?? 2009 Elsevier B.V.

Dai, S.; Zhao, L.; Peng, S.; Chou, C.-L.; Wang, X.; Zhang, Y.; Li, D.; Sun, Y.

2010-01-01

310

minerals  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

311

Ball clay  

USGS Publications Warehouse

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.

Virta, R. L.

2013-01-01

312

Clay Houses  

ERIC Educational Resources Information Center

In this article, the author describes a project designed for fourth-graders that involves making clay relief sculptures of houses. Knowing the clay houses will become a family heirloom makes this lesson even more worth the time. It takes three classes to plan and form the clay, and another two to underglaze and glaze the final products.

Pedro, Cathy

2011-01-01

313

Mixed-Layered Clays as Evidence for Widespread Diagenesis on Mars  

NASA Astrophysics Data System (ADS)

The abundance of clay mineral deposits in the >3.5 Ga Noachian crust of Mars suggests widespread water-rock interaction and aqueous alteration during the first billion years of the planet's history. In addition, the ancient rock record of Mars is remarkably well preserved compared with that of Earth due to the lack of crustal recycling. However, aqueous and eolian sedimentation, volcanism, and deposition of impact ejecta all likely contributed to the geologic record of Mars for several billion years, and all of these processes would contribute to the burial of near-surface sediments. On Earth, the burial of smectitic clay minerals results in the formation of mixed-layered clay minerals, commonly illite/smectite or chlorite/smectite, which are ultimately transformed to illite and chlorite, respectively. The rate and extent of these processes depend on factors such as initial smectite composition, fluid chemistry, time, and temperature. The oldest smectites on Earth may only be 600 Myr old, whereas smectites identified on Mars are inferred to be >3.5 Gyr old, a remarkable difference even in the absence of plate tectonics for the latter. If Martian clay mineral deposits are truly this ancient and still smectitic, then this would have profound implications for geothermal gradients and/or the duration of water-rock interaction in the ancient crust. Here we examine visible-near infrared CRISM spectra for a variety of Martian clay deposits in greater detail, exploring the possibility that many previously identified smectite deposits are more consistent with mixed-layered chlorite/smectite. Analysis of laboratory data for di- and trioctahedral smectites and mixed-layered chlorite/smectite reveals that subtle differences in the reflectance spectra between these clay minerals can be parameterized and thus allow them to be distinguished from each other. Alhough some ambiguity exists in distinguishing physical mixtures of chlorite and smectite from mixed-layered chlorite/smectite, these cases can often be identified by visual inspection of the reflectance spectra. Application of our derived parameters to CRISM spectra reveals that most clay mineral deposits on Mars are consistent with mixed-layered chlorite/smectite or chlorite, and that smectitic clays are relatively uncommon. This suggests that most clay minerals on Mars have experienced some degree of chloritization and diagenesis if they were originally formed as smectite. Future work that helps to constrain the exact degree of chloritization may also help to constrain the geothermal gradient on early Mars, longevity of crustal fluid circulation, and the potential for Martian clay deposits to preserve organic material.

Milliken, R.; Bristow, T. F.; Bish, D. L.

2011-12-01

314

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

USGS Publications Warehouse

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.

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

315

Modelling the Abundance and Temporal Variation in the Production of Bilberry (Vaccinium myrtillus L.) in Finnish Mineral Soil Forests  

Microsoft Academic Search

Empirical models for the abundance and berry yield of V. myrtillus were constructed using generalized linear mixed model (GLMM) techniques. The percentage coverage of bilberry was predicted as a function of site and stand characteristics using the permanent sample plots of the National Forest Inventory (NFI) in 1995. The number of bilberries was predicted as a function of percentage coverage

Jari Miina; Juha-Pekka Hotanen; Kauko Salo

316

Clay Minerals in Response to the Mid-Pliocene Global Warmth in Polar Regions (ODP, Site 911, Yermak Plateau, Arctic Ocean and Site 1165, Prydz Bay, Antarctica)  

NASA Astrophysics Data System (ADS)

The Mid-Pliocene global warmth (MPGW), a period when the global average temperatures were significantly warmer than the present, was possibly caused by higher CO2 levels than today and significantly stronger ocean thermohaline circulation due to drastic climatic changes in the Southern Ocean. In the Northern Hemisphere, MPGW could have been one decisive trigger for the intensification of glaciation at 2.7 Ma. Some recent studies in the East Antarctica have shown that the East Antarctic Ice Sheet (EAIS) may have varied from a polythermal, dynamic condition to a predominantly cold stable state as recently as the Pliocene period, including MPGW. This presentation may illuminate the Mid-Pliocene climate conditions of the Arctic Ocean and the dynamics of the EAIS based on a clay mineral study. Research of this kind, integrated with other proxies, can provide some indication of how the Earth may respond to the future global warming The Ocean Drilling Program (ODP) Site 911 was drilled on the Yermak Plateau, Arctic Ocean to a depth of 505.8 meters below the seafloor (mbsf). It contained sediments from the Pliocene to Pleistocene ages. ODP Site 1165 was drilled on the Wild Drift on the Continental Rise off Prydz Bay, East Antarctica, to a total depth of 999.1 mbsf. Of special interest is the sediment column between 0 and 50 mbsf, which consists of a well-preserved section of Pliocene- to Pleistocene-age sediments. The Pliocene sediments at Site 911 have higher smectite content and lower kaolinite and chlorite contents compared to the Pleistocene samples. This may indicate more active sea-ice conditions for smectite transportation from the Kara and Laptev Seas during the Pliocene compared to the Pleistocene sea-ice transportation conditions. The Mid-Pliocene sediments at Site 1165 show increasing smectite contents and decreasing illite contents and suggest that the EAIS at that time may have been more dynamic than that during the Plio-Pleistocene transition, to which the results were compared.

Junttila, J.; Strand, K.

2005-12-01

317

Clay alteration of volcaniclastic material in a submarine geothermal system, Bay of Plenty, New Zealand  

NASA Astrophysics Data System (ADS)

The Calypso Hydrothermal Vent Field (CHVF) is located along an offshore extension of the Taupo Volcanic Zone (TVZ), an area of abundant volcanism and geothermal activity on the North Island of New Zealand. The field occurs within a northeast-trending submarine depression on the continental shelf approximately 10-15 km southwest of the White Island volcano in the Bay of Plenty. The graben has been partially filled by tephra from regional subaerial volcanic eruptions, and active hydrothermal venting occurs at several locations along its length. The vents occur at water depths of 160 to 190 m and have temperatures up to 201 °C. Recovered samples from the vent field include variably cemented and veined volcaniclastic sediments containing an assemblage of clay minerals, amorphous silica, barite, As-Sb-Hg sulfides, and abundant native sulfur. The volcanic glass has been altered primarily to montmorillonite and mixed-layer illite-montmorillonite; illite, and possibly minor talc and mixed-layer chlorite-smectite or chlorite-vermiculite are also present. A hydrothermal versus diagenetic origin for the smectite is indicated by the presence of both illite and mixed-layer clays and by the correlation between the abundance of clay minerals and the abundance of native sulfur in the samples. The mineralization and alteration of the volcanic host rocks are similar to that observed in near-neutral pH geothermal systems on land in the TVZ (e.g., Broadlands-Ohaaki). However, the clay minerals in the CHVF have a higher concentration of Mg in the dioctahedral layer and a higher interlayer Na content than clay minerals from Broadlands-Ohaaki, reflecting the higher concentrations of Mg and Na in seawater compared to meteoric water. Minerals formed at very low pH (e.g., kaolinite and alunite), typical of steam-heated acid-sulfate type alteration in the TVZ geothermal environment, were not found. Mixing with seawater likely prevented the formation of such low-pH mineral assemblages. The occurrence of illite and mixed-layer illite-smectite close to the seafloor in the CHVF, rather than at depth as in the Broadlands system, is interpreted to reflect the higher pressures associated with submarine venting. This allows hotter fluids to be discharged before they boil, and thus minerals that are encountered mainly at depth in subaerial geothermal systems can form close to the seafloor.

Hocking, Michael W. A.; Hannington, Mark D.; Percival, Jeanne B.; Stoffers, Peter; Schwarz-Schampera, Ulrich; de Ronde, C. E. J.

2010-04-01

318

Evaluating the geochemically induced swelling/shrinkage of the near-field host clay rock using a THC model and the diffuse double layer theory  

NASA Astrophysics Data System (ADS)

One advantage of emplacing nuclear waste in a clay formation is the potential self-sealing capability due to clay swelling. The swelling properties of the near-field host clay rock can be altered due to geochemical factors, including changes in groundwater geochemistry, proportions of exchangeable cations, and swelling clay mineral abundances. The clay host rock can also undergo geochemical changes due to the interaction with the engineered barrier system (EBS) materials. In this paper, coupled thermal, hydrological, and chemical (THC) models are linked with a swelling model based on diffuse double layer (DDL) theory and changes in the swelling properties of clay host rocks in the near field area are evaluated. Findings based on THC simulations using the reaction-transport code TOUGHREACT include: 1) Significant changes in the swelling pressure could be expected depending on various hydrogeologic and geochemical conditions. The change of hydration rate of the EBS (via the adjustment of tortuosity) could have significant effect on the swelling pressure. 2) Geochemically-induced swelling/shrinkage only occurs in the near-field area, within a few meters from the EBS interface. 3) Swelling/shrinkage induced porosity change is generally much smaller than that caused by mineral precipitation/dissolution. 4) The geochemically-induced swelling/shrinkage of host clay rock is the combined effect of variation in the pore water geochemistry, exchangeable cations, and smectite abundance. Neglecting any of these three latter factors might lead to a miscalculation of the geochemically-induced swelling pressure.

Zheng, L.; Liu, H.; Birkholzer, J. T.; Houseworth, J. E.; Sonnenthal, E. L.

2011-12-01

319

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

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

320

Clay petrology of the Upper Triassic/Lower Jurassic terrestrial strata of the Newark Supergroup, Connecticut Valley, U.S.A.  

NASA Astrophysics Data System (ADS)

The clay mineralogy of the Newark Supergroup (Upper Triassic/Lower Jurassic) in the Connecticut Valley was studied by X-ray diffraction analysis. Clay minerals identified in 126 samples are illite, chlorite, smectite, kaolinite, vermiculite, expandable chlorite, mixed-layer illite/smectite, mixed-layer chlorite/smectite, and mixed-layer chlorite/vermiculite. In general, the rocks are illitic with subordinate amounts of chlorite. However, the various lithofacies in the Newark Supergroup are characterized by distinct clay-mineral assemblages. Red beds of floodplain origin contain clays mainly of detrital nature with 2M illite most abundant. Subordinate amounts of chlorite, smectite, vermiculite, kaolinite and mixed-layer illite/smectite are also present. An interstratified chlorite/vermiculite occurs in red mudstone underlying basalt flows. Lacustrine gray beds are generally characterized by the clay-mineral assemblage 1Md illite + chlorite with minor amounts of smectite ane expandable chlorite. An interstratified chlorite/smectite predominates in gray mudstone associated with perennial lake cycles in the East Berlin Formation. Black shales of deeper lacustrine origin contain the assemblage 1Md ifillite + trioctahedral smectite and traces of chlorite. Illite and smectite also occur as mixed-layer phases. In many respects, the distribution of clay minerals in the Connecticut Valley can be likened to the general scheme proposed for the Permo-Triassic basins of Europe and Africa. These display both vertical and horizontal variations in clay-mineral assemblages that reflect the chemical and spatiotemporal evolution of intrabasin depositional and diagenetic environments. Chemical data indicate that magnesium, especially, was concentrated in the black muds of large perennial lakes that intermittently occupied the Connecticut rift valley. Pore waters derived from these sediments played an important role in the development of Mg-rich 2 : 1 and interstratified clay minerals during early diagenesis.

April, Richard H.

1981-08-01

321

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

322

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)

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.

Dufréchou, Grégory; Granjean, Gilles; Bourguignon, Anne

2014-05-01

323

CHROME MICA.CLAY, TEMPLE MOUNTAIN, UTAH  

Microsoft Academic Search

chrome mica-clay occurs at Temple Mountain, utah in association with uranium mineralization. It contains approximately 0.4 to 0.6 per cent CrzOa and consists of mixed h.rrtonucrrom The rigorous application of r-ray difiraction and allied minerarogical techniques to the fine fractions of clays has gained momentum during recent years. As a result, somewhat indefinite clay material long ago recognized as hydromica

Paur F. Knnn

324

Surface Modification of Clays and Related Materials  

Microsoft Academic Search

This review analyzes various ways by which the surfaces of clay particles and related minerals can be non?covalently modified, as well as some of the analytical approaches with which these surface modifications can be measured and quantified. Among the principal methods of modification of the surface properties of clays and other metal oxide surfaces is treatment with cationic surfactants comprising

C. J. van Oss; R. F. Giese

2003-01-01

325

CLAY AND SHALE--2003 18.1 CLAY AND SHALE  

E-print Network

primarily of attapulgite, calcium-rich montmorillonite, and quartz. In many countries, all calcium-rich montmorillonite clays, including calcium-rich bentonite, are called fuller's earth, and attapulgite is grouped, rutile, and smectite minerals are a few other components of kaolin deposits. Absorption qualities

326

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

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).

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

1992-01-01

327

Heterogeneous clay-manganese(II) oxidation catalyst  

Microsoft Academic Search

A manganese(II)-Schiff base complex has been heterogenized by its intercalation into clay minerals. The incorporation of the homogeneous manganese(II) complexes in the interlayer space of aluminosilicate mineral is accomplished by a cation exchange process. The obtained clay-manganese(II) composite has been studied by chemical analysis, X-ray diffraction and FT-IR spectroscopy. The new catalytic material has been evaluated as oxidation catalyst. Our

D Gournis; M Louloudi; M. A Karakassides; C Kolokytha; K Mitopoulou; N Hadjiliadis

2002-01-01

328

Ball clay  

USGS Publications Warehouse

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.

Virta, R. L.

2012-01-01

329

Constraints on Mineral-Phase Abundances and Compositions in the Low-Albedo Northern Plains of Mars using MGS-TES, OMEGA, and Laboratory Spectral Data.  

NASA Astrophysics Data System (ADS)

The abundances and compositions of mineral-phases in the low-albedo northern plains of Mars have been a focus of considerable study and debate in recent years. Large expanses of Acidalia Planitia surface materials are characterized by the MGS-TES Surface Type 2 (ST2) spectral endmember [1]. The ST2 spectrum is distinguished by a rounded, slightly V-shaped 800 to 1200 wavenumber region of absorption and uniform absorption at low wavenumbers. The same areas are also characterized by an OMEGA spectral signature that is relatively featureless, but with a strong blue slope (decreasing reflectance as a function of wavelength) from 0.9 to 2.6 microns [2]. A central question with both observations is whether they represent the spectral signature of a high-silica primary volcanic lithology (andesite) or the effects of chemical alteration on basaltic surface materials. Ambiguity in classifying the ST2 lithology arises because a spectral component of this unit (20-30 vol %) can be interpreted as volcanic siliceous glass [1, 3] (an abundant phase in andesite) or a combination of secondary phases found in altered basalt (amorphous silica-rich coatings, palagonite, smectite, and zeolite) [4-8]. Similarly, the OMEGA spectrum lacks evidence of distinct mafic mineral bands (found in andesite) as well as molecular vibration absorptions due to H2O and/or OH-, which might indicate the presence of well- crystalline alteration products and phyllosilicates [2]. Constraining these compositions is significant for understanding the petrogenesis of the Martian crust and its subsequent alteration. Identification of widespread andesite may imply an early episode of plate tectonics on Mars while altered basalt would indicate extensive surface-volatile interactions. The objective of this study is to combine TES and OMEGA observations of the low-albedo northern plains for comparison to laboratory thermal infrared and visible/near-infrared measurements of primary volcanic lithologies (basalt to dacite) and chemically weathered basalts from different terrestrial environments. Thermal infrared emission and visible/near-infrared reflectance measurements will be performed on rock chips, sorted particle sizes, and soil samples. Emission spectra have been acquired at Arizona State University using a Nicolet Nexus 670 FTIR spectrometer that has been modified to measure emitted energy over the range of 5 to 50 microns at 2 wavenumber spectral sampling. Bidirectional reflectance measurements from 0.32 to 2.55 microns at 0.05 micron sampling will be collected at the Brown University RELAB facility. Work by [5] on palagonitic alteration rinds developed on basaltic rocks demonstrates the effectiveness of combining wavelength regions in laboratory studies and applying results to orbital observations. In our study, we further this type of work by examining both unaltered volcanics and chemically altered basalts in an effort to constrain interpretations of the igneous lithology and the degree of secondary mineral-phase production in Acidalia Planitia. [1] Bandfield et al. (2000) Science, 287, 1626 1630. [2] Mustard et al. (2005) Science, 1594-1597. [3] Hamilton et al. (2001) JGR, 106, 14,733-14,746. [4] Wyatt and McSween (2002) Nature, 417, 263-266. [5] Morris et al. (2003) 6 Int. Mars. Conf, Abstract 3111. [6] Kraft et al. (2003) GRL, 30, 24, 2288, doi 10.1029.2003GL018848. [7] Ruff (2004) Icarus, 108, 131-143. [8] Michalski et al. (2005) Icarus, 174, 161-177.

Wyatt, M. B.; Mustard, J. F.

2006-12-01

330

Clay at Nili Fossae  

NASA Technical Reports Server (NTRS)

This image of the Nili Fossae region of Mars was compiled from separate images taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and the High-Resolution Imaging Science Experiment (HiRISE), two instruments on NASA's Mars Reconnaissance Orbiter. The images were taken at 0730 UTC (2:30 a.m. EDT) on Oct. 4, 2006, near 20.4 degrees north latitude, 78.5 degrees east longitude. CRISM's image was taken in 544 colors covering 0.36 to 3.92 micrometers, and shows features as small as 18 meters (60 feet) across. HiRISE's image was taken in three colors, but its much higher resolution shows features as small as 30 centimeters (1 foot) across.

CRISM's sister instrument on the Mars Express spacecraft, OMEGA, discovered that some of the most ancient regions of Mars are rich in clay minerals, formed when water altered the planet's volcanic rocks. From the OMEGA data it was unclear whether the clays formed at the surface during Mars' earliest history of if they formed at depth and were later exposed by impact craters or erosion of the overlying rocks. Clays are an indicator of wet, benign environments possibly suitable for biological processes, making Nili Fossae and comparable regions important targets for both CRISM and HiRISE.

In this visualization of the combined data from the two instruments, the CRISM data were used to calculate the strengths of spectral absorption bands due to minerals present in the scene. The two major minerals detected by the instrument are olivine, a mineral characteristic of primitive igneous rocks, and clay. Areas rich in olivine are shown in red, and minerals rich in clay are shown in green. The derived colors were then overlayed on the HiRISE image.

The area where the CRISM and HiRISE data overlap is shown at the upper left, and is about 5 kilometers (3 miles) across. The three boxes outlined in blue are enlarged to show how the different minerals in the scene match up with different landforms. In the image at the upper right, the small mesa -- a flat-topped hill -- at the center of the image is a remnant of an overlying rock layer that was eroded away. The greenish clay areas at the base of the hill were exposed by erosion of the overlying rock. The images at the upper right and lower left both show that the reddish-toned olivine occurs as sand dunes on top of the greenish clay deposits. The image at the lower right shows details of the clay-rich rock, including that they are extensively fractured into small, polygonal blocks just a few meters in size. Taken together, the CRISM and HiRISE data show that the clay-rich rocks are the oldest at the site, that they are exposed where overlying rock has been eroded away, and that the olivine is not part of the clay-rich rock. Rather it occurs in sand dunes blowing across the clay.

Many more images of Nili Fossae and other clay-rich areas will be taken over the next two years. They will be used to try to understand the earliest climate of Mars that is recorded in the planet's rocks.

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad.

CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and map the geology, composition and stratigraphy of surface features. The instrument will also watch the seasonal variations in Martian dust and ice aerosols, and water content in surface materials o leading to new understanding of the climate.

NASA's Jet Propulsion Laboratory, a division of the Califonia Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor and built the spacecraft.

2006-01-01

331

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

E-print Network

. INTRODUCTION Sorption reactions at the mineral/water interface greatly affect the mobility, speciation, fate complexation models have been developed and applied to describe metal sorption reactions at the solid-water investigations were combined with X-ray Absorption Fine Structure (XAFS) measurements to determine Ni sorption

Sparks, Donald L.

332

Characterizing regional soil mineral composition using spectroscopyand geostatistics  

USGS Publications Warehouse

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.

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

2013-01-01

333

Clay for Little Fingers.  

ERIC Educational Resources Information Center

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…

Koster, Joan Bouza

1999-01-01

334

Clay swelling — A challenge in the oilfield  

NASA Astrophysics Data System (ADS)

Water-based drilling fluids are increasingly being used for oil and gas exploration, and are generally considered to be more environmentally acceptable than oil-based or synthetic-based fluids. Unfortunately, their use facilitates clay hydration and swelling. Clay swelling, which occurs in exposed sedimentary rock formations, can have an adverse impact on drilling operations and may lead to significantly increased oil well construction costs. Minimizing clay swelling is therefore an important area attracting a large amount of interest from both academia and industry. To effectively reduce the extent of clay swelling the mechanism by which clay minerals swell needs to be understood so that efficient swelling inhibitors may be developed. Acceptable clay swelling inhibitors must not only significantly reduce clay hydration, but must also meet increasingly stringent environmental guidelines while remaining cost effective. The development of these inhibitors, which are generally based upon water soluble polymers, therefore represents a challenge to oilfield geochemistry. This review aims to provide a comprehensive understanding of the mechanism by which clay minerals swell and what steps have been taken in the development of effective and environmentally friendly clay swelling inhibitors.

Anderson, R. L.; Ratcliffe, I.; Greenwell, H. C.; Williams, P. A.; Cliffe, S.; Coveney, P. V.

2010-02-01

335

Clay Boats  

NSDL National Science Digital Library

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.

Engineering K-Phd Program

336

Reversible surface-sorption-induced electron-transfer oxidation of Fe(II) at reactive sites on a synthetic clay mineral  

NASA Astrophysics Data System (ADS)

The sorption of 57Fe(II) onto an Fe-free, mineralogically pure and Ca-saturated synthetic montmorillonite sample (structural formula: Ca 0.15(Al 1.4Mg 0.6)(Si 4)O 10(OH,F) 2), was studied as a function of pH under strictly anoxic conditions (N 2 glove box atmosphere, O 2 content <1 ppm), using wet chemistry and cryogenic ( T = 77 K) 57Fe Mössbauer spectrometry. No Fe(III) was detected in solution at any pH. However, in pH conditions where Fe(II) is removed from solution, a significant amount of surface-bound Fe(III) was produced, which increased with pH from 0% to 3% of total Fe in a pre-sorption edge region (i.e. at pH < 7.5 where about 15% of total Fe is sorbed) to 7% of total Fe when all Fe is sorbed. At low pH, where the pre-sorption edge plateau occurs (2 < pH < 7.5), the total sorbed-Fe amount remained constant but, within this sorbed-Fe pool, the Fe(III)/Fe(II) ratio increased with pH, from 0.14 at pH 2 up to 0.74 at pH 7. The pre-sorption edge plateau is interpreted as cation exchange on interlayer surfaces together with a sorption phenomenon occurring on highly reactive (i.e. high affinity) surface sites. As pH increases and protons are removed from the clay edge surface, we propose that more and more of these highly reactive sites acquire a steric configuration that stabilizes Fe(III) relative to Fe(II), thereby inducing a Fe to clay particle electron transfer. A sorption model based on cation exchange combined with surface complexation and electron transfers reproduces both wet chemical as well as the Mössbauer spectrometric results. The mechanism is fully reversible: sorbed-Fe is reduced as pH decreases (Mössbauer solid-state analyses) and all Fe returned to solution is returned as Fe(II) (solution analyses). This would not be the case if the observed oxidations were due to contaminant oxidizing agents in solution. The present work shows that alternating pH may induce surface redox phenomena in the absence of an electron acceptor in solution other than H 2O.

Géhin, A.; Grenèche, J.-M.; Tournassat, C.; Brendlé, J.; Rancourt, D. G.; Charlet, L.

2007-02-01

337

Desorption of arsenic from clay and humic acid-coated clay by dissolved phosphate and silicate.  

PubMed

Arsenic (As) contaminated aquifers contain iron minerals and clays that strongly bind As at their surfaces. It was suggested that As mobilization is driven by natural organic matter (including fulvic acids (FA) and humic acids (HA)) present in the aquifers either via providing reducing equivalents for reductive dissolution of Fe(III) (hydr)oxides or via competitive desorption of As from the mineral surfaces. In the present study we quantified sorption of As(III) and As(V) to Ca(2+)-homoionized illite (IL) and to kaolinite (Kao) as well as to HA-coated clays, i.e., illite-HA (IL-HA) and kaolinite-HA (Kao-HA) at neutral pH. Clay-HA complexes sorbed 28-50% more As than clay-only systems upon addition of 100?M As(III)/As(V) to 0.5g of clay or HA-clay with Ca(2+) probably playing an important role for HA binding to the clay surface and As binding to the HA. When comparing sorption of As(V) and As(III) to clay and HA-clay complexes, As(V) sorption was generally higher by 15-32% than sorption of As(III) to the same complexes. IL and IL-HA sorbed 11-28% and 6-11% more As compared to Kao and Kao-HA, respectively. In a second step, we then followed desorption of As from Kao, Kao-HA, IL and IL-HA by 100 and 500?M phosphate or silicate both at high (0.41-0.77?mol As/g clay), and low (0.04 to 0.05?mol As/g clay) As loadings. Phosphate desorbed As to a larger extent than silicate regardless of the amount of As loaded to clay minerals, both in the presence and absence of HA, and both for illite and kaolinite. At high loadings of As, the desorption of both redox species of As from clay-HA complexes by phosphate/silicate ranged from 32 to 72% compared to 2-54% in clay only systems meaning that As was desorbed to a larger extent from HA-coated clays compared to clay only systems. When comparing As(III) desorption by phosphate/silicate to As(V) desorption in high As-loading systems, there was no clear trend for which As species is desorbed to a higher extent in the four clay systems meaning that both As species behave similarly regarding desorption from clay surfaces by phosphate/silicate. Similarly, no significant differences were found in high As-loading systems in the amount of As desorbed by phosphate/silicate when comparing Kao vs. IL and Kao-HA vs IL-HA systems meaning that both clay types behave similarly regarding desorption of As by phosphate/silicate. At low As loadings, up to 80% of As was desorbed by phosphate and silicate with no noticeable differences being observed between different As species, different types of clay, clay vs clay-HA or the type of desorbant (phosphate and silicate). The results of this study showed that HA sorption to Ca(2+)-homoionized clay minerals can increase As binding to the clay although the As sorbed to the clay-HA is also released to a greater extent by competing ions such as phosphate and silicate. Desorption of As depended on the initial loadings of As onto the clay/clay-HA. Based on our results, the effect of humic substances on sorption of As and on desorption of As by phosphate and silicate has to be considered in order to fully understand and evaluate the environmental behavior of As in natural environments. PMID:22115087

Sharma, Prasesh; Kappler, Andreas

2011-11-01

338

Clay mineralogy of the riverine sediments of Hainan Island, South China Sea: Implications for weathering and provenance  

NASA Astrophysics Data System (ADS)

Clay mineralogy of 54 fluvial samples collected from 20 major rivers on Hainan Island are investigated in order to determine compositional changes of clay minerals and to assess the weathering processes. The clay mineral assemblages consist dominantly of kaolinite (31-66%), with a lesser abundance of chlorite (22-44%) and illite (4-33%), and a trace amount of smectite (0-15%). Fluvial sediments from the east and northwest of Hainan Island are characterized by a higher kaolinite content and illite chemical index and poorer illite crystallinity than those from southwest Hainan. Only minor smectite (mean of 7%) occurs in the sediments from west Hainan; smectite is total lacking in east Hainan. Compared with the adjacent basins, Hainan Island is characterized by moderate to intensive chemical weathering with strong hydrolysis. Our results suggest that rainfall is the principal factor controlling the intensity of chemical weathering on Hainan Island, with more intense chemical weathering occurring in eastern and northwestern Hainan. Another practical implication of this study is that it provides a “missing” end member (Hainan Island) in the provenance discrimination study focused on the northern South China Sea (SCS). Hainan fine-grained sediments likely play an important role in providing clay minerals to the northern SCS carried by the South China Sea Warm Current (SCSWC) during the summer.

Hu, Bangqi; Li, Jun; Cui, Ruyong; Wei, Helong; Zhao, Jingtao; Li, Guogang; Fang, Xisheng; Ding, Xue; Zou, Liang; Bai, Fenglong

2014-12-01

339

Investigation of the microporous structure of clays and pillared clays by {sup 129}Xe NMR.  

SciTech Connect

{sup 129}Xe NMR spectroscopy of xenon gas adsorbed in clays and pillared clays has been used to glean information on the interlayer gallery height of clays before and after pillaring. Two clay minerals were studied, a Ca{sup 2+}-montmorillonite and Bentonite L. The NMR results indicate that the effective interlamellar spacing of the montmorillonite increased from 5.4 to 8.0 Angstroms after pillaring with aluminum polyoxohydroxy Keggin cations. These data are consistent with X-ray powder diffraction results, which show a corresponding increase in gallery height from 5.6 to 8.4 Angstroms.

Tsaio, C.-J.; Carrado, K. A.; Botto, R. E.; Chemistry

1998-04-01

340

Thermo Gravimetric and Differential Thermal Analysis of Clay of Western Rajasthan (india)  

NASA Astrophysics Data System (ADS)

The paper presents the study of thermo gravimetric and differential thermal analysis of blended clay. Western part of Rajasthan (India) is rich resource of Ball clays and it is mainly used by porcelain, sanitary ware, and tile industry. The quality and grade of clay available in the region vary from one deposit to other. To upgrade the fired colour and strength properties, different variety of clays may be blended together. The paper compares the results of thermal analysis one of blended clay B2 with reference clay of Ukraine which is imported by industries owners. The result revealed that the blended clay is having mineral kaolinite while the Ukrainian clay is Halloysite.

Shekhawat, M. S.

341

A possible energetic role of mineral surfaces in chemical evolution  

NASA Astrophysics Data System (ADS)

The postulated roles of clays and other minerals in chemical evolution and the origin of life are reconsidered in terms of the interaction of these minerals with penetrating sources of energy such as ionizing radiation and mechanical stress. This interaction, including such facets as excitation, degradation, storage, and transfer, is considered here with regard to its profound potential for altering the capabilities of minerals to serve both as substrates for prebiological chemistry and as inorganic prototypic life forms. The interaction of minerals and energy in relationship to surface chemistry is discussed in terms of the spectroscopic properties of minerals, the interaction of energy with condensed phases, some commonly accepted concepts of heterogeneous catalysis in the absence of electronic energy inputs, and some commonly accepted and novel means by which surface activity might be enhanced in the presence of energy inputs. An estimation is made of the potential contribution of two poorly characterized prebiotic energy sources, natural radioactive decay and triboelectric energy. These estimates place a conservative lower limit on their prebiotic abundance. Also some special properties of these energy sources, relative to solar energy, are pointed out which might give them particular suitability for driving reactions occurring under geological conditions. Skeletal support for this broadly defined framework of demonstrated and potential relationships between minerals, electronic excitation, and surface reactivity, as applied to chemical evolution, is provided from the results of our studies on 1/1 clays. We have discovered and partially characterized a number of novel luminescent properties of these clays, that indicate energy storage and transfer processes in clays. These luminescent properties are interpreted in relationship to the electron spin resonance phenomena, to provide a basis for estimating the potential significance of energy storage and transduction in monitoring or driving clay surface chemistry. Consideration of the electronic structure of abundant minerals in terms of band theory and localized defect centers provides a predictive theoretical framework from which to rationalize the capacity of these materials to store and transduce energy. The bulk crystal is seen as a collecting antenna for electronic energy, with the defect centers serving as storage sites. The clay properties produced by isomorphic substitution appear to be intimately associated with all of the life-mimetic chemical processes that have been attributed to clays. It appears sensible to postulate that the energetic properties of these substitutional defect centers may also be influential in these biomimetic processes: the promotion of surface reactions, storage of information, replication with transfer of information, and asymmetric separation of electrical charges, as well as their more recently hypothesized roles in energy storage and transduction. The identity of the sites implicated in all of the biomimetic functions of clays as well as their capacity for energy storage is seen to offer significant potential for coupling these functions to an environmental energy source. A yet more specific and experimentally testable hypothesis is offered for a new biomimetic process performed by clays. This hypothesis is that energy stored near isomorphically substituted sites provides the energetic basis for the coupled transport of electrical charge and/or electronic energy through the clay layer, which operates via environmental activation of electron/hole mobility. This is to say that mobility of charge/electronic excitation between defect centers serves as the basis for a primordial inorganic electron transport chain.

Coyne, Lelia M.

1985-09-01

342

A study of selected chemical admixtures for clay soil stabilization  

E-print Network

Clay, the Type Grumusol: I Field MorpholoSy and GeoSraphy, JF Soil Sci. Soc. of Am. Pt * d', V 1. 20, pp. 8383525, JD56. 12, Whitey 'W A ~ llater Sorption Properties of Homoionic Clay Minerals, " Ph, D. Thesis, University of Illinois, 1955. 13... Clay, the Type Grumusol: I Field MorpholoSy and GeoSraphy, JF Soil Sci. Soc. of Am. Pt * d', V 1. 20, pp. 8383525, JD56. 12, Whitey 'W A ~ llater Sorption Properties of Homoionic Clay Minerals, " Ph, D. Thesis, University of Illinois, 1955. 13...

Gover Belendez, Charles Baker

2012-06-07

343

Reaction of Sodium Hydroxide with Silicate Minerals.  

National Technical Information Service (NTIS)

The reactions of individual silicate minerals with caustic solution were measured over a 1-week period. These silicate minerals included: two feldspars (microcline and albite), two micas (biotite and muscovite), and three clays (chlorite, Kaolinite and mo...

S. D. Thornton

1986-01-01

344

Burnt clay magnetic properties and palaeointensity determination  

NASA Astrophysics Data System (ADS)

Burnt clay structures found in situ are the most valuable materials for archaeomagnetic studies. From these materials the full geomagnetic field vector described by inclination, declination and intensity can be retrieved. The reliability of the obtained directional results is related to the precision of samples orientation and the accuracy of characteristic remanence determination. Palaeointensity evaluations depend on much more complex factors - stability of carried remanent magnetization, grain-size distribution of magnetic particles and mineralogical transformations during heating. In the last decades many efforts have been made to shed light over the reasons for the bad success rate of palaeointensity experiments. Nevertheless, sometimes the explanation of the bad archaeointensity results with the magnetic properties of the studied materials is quite unsatisfactory. In order to show how difficult is to apply a priory strict criteria for the suitability of a given collection of archaeomagnetic materials, artificial samples formed from four different baked clays are examined. Two of the examined clay types were taken from clay deposits from different parts of Bulgaria and two clays were taken from ancient archaeological baked clay structures from the Central part of Bulgaria and the Black sea coast, respectively. The samples formed from these clays were repeatedly heated in known magnetic field to 700oC. Different analyses were performed to obtain information about the mineralogical content and magnetic properties of the samples. The obtained results point that all clays reached stable magnetic mineralogy after the repeated heating to 700oC, the main magnetic mineral is of titano/magnetite type and the magnetic particles are predominantly with pseudo single domain grain sizes. In spite that, the magnetic properies of the studied clays seem to be very similar, reliable palaeointensity results were obtained only from the clays coming from clay deposits. The palaeointensity experiments for the samples formed from the ancient baked clays completely failed to give relibable results.

Avramova, Mariya; Lesigyarski, Deyan

2014-05-01

345

CLAY AND CLAY-SUPPORTED REAGENTS IN ORGANIC SYNTHESES  

EPA Science Inventory

CLAY AND CLAY-SUPPORTED REAGENTS HAVE BEEN USED EXTENSIVELY FOR SYNTHETIC ORGANIC TRANSFORMATIONS. THIS OVERVIEW DESCRIBES THE SALIENT STRUCTURAL PROPERTIES OF VARIOUS CLAY MATERIALS AND EXTENDS THE DISCUSSION TO PILLARED CLAYS AND REAGENTS SUPPORTED ON CLAY MATERIALS. A VARIET...

346

Low-temperature, mineral-catalyzed air oxidation: a possible new pathway for PAH stabilization in sediments and soils.  

PubMed

Reactivity of polycyclic aromatic hydrocarbons (PAHs) in the subsurface is of importance to environmental assessment, as they constitute a highly toxic hazard. Understanding their reactivity in the long term in natural recovering systems is thus a key issue. This article describes an experimental investigation on the air oxidation of fluoranthene (a PAH abundant in natural systems polluted by industrial coal use) at 100°C on different mineral substrates commonly found in soils and sediments (quartz sand, limestone, and clay). Results demonstrate that fluoranthene is readily oxidized in the presence of limestone and clay, leading to the formation of high molecular weight compounds and a carbonaceous residue as end product especially for clay experiments. As demonstrated elsewhere, the experimental conditions used permitted the reproduction of the geochemical pathway of organic matter observed under natural conditions. It is therefore suggested that low-temperature, mineral-catalyzed air oxidation is a mechanism relevant to the stabilization of PAHs in sediments and soils. PMID:20964431

Ghislain, Thierry; Faure, Pierre; Biache, Coralie; Michels, Raymond

2010-11-15

347

Alterations in the non-clay-mineral fraction of pelitic rocks the diagenetic to low-grade metamorphic transition, Ouachita Mountains, Oklahoma and Arkansas  

SciTech Connect

The transformation of smectite to illite has been cited by many authors as a source of silica during diagenesis of mudrocks. Illites themselves, however, undergo chemical changes as they recrystallize into micas during high-grade diagenesis/low-grade metamorphism. Average compositions of phyllosilicates from the literature suggest that an equivalent amount of silica is available from transformation of illite to muscovite as from illitization of smectites. The fate of silica released by this process has not been reported, but could be a major contributor to the silt-size quartz population. The quartz and feldspar fraction of pelites from the Stanley Shale (Mississippian) in the Ouachita Mountains of Oklahoma and Arkansas was separated using sodium bisulfate fusions. The mineralogy and the grain-size distribution of this fraction were determined using standard petro-graphic and X-ray diffraction (XRD) techniques. Bulk rock samples were analyzed using X-ray fluorescence (XRF) and instrumental neutron activation analysis (INAA) methods. The data obtained were related to illite crystallinity and vitrinite reflectance as reported by Guthrie el al. (1986) and Houseknecht and Matthews (1985). The authors results are consistent with reported differences between quartz in schists and their shale precursors, and suggest that release of silica during diagenesis of phyllosilicates continues after the smectite-illite transformation. This silica precipitates as quartz within the pelite, consistent with the suggestion by Blatt (1987) that metapelites are the source of abundant silt-size quartz. The lack of whole-rock chemical variation with thermal maturity implies closed-system behavior across much of the pelite-to-metapelite transition.

Totten, M.W.; Blatt, H. (Univ. of Oklahoma, Norman, OK (United States). School of Geology and Geophysics)

1993-09-01

348

Ionizing radiation-induced defects in smectite clays  

NASA Astrophysics Data System (ADS)

The interaction of ?-rays with smectites induces paramagnetic defects in the structure of these clay minerals. The EPR spectra of three different smectites detect the creation of structural defects and trapping of organic free radicals in the clay structure upon irradiation. The defects are assigned to positive holes or trapped electrons stabilised by existing local charge imbalances in the mineral lattice. The organic radicals are derived from organic compounds present as impurities in the crystal lattice of the clay minerals. In addition, ?-rays cause migration of small interlayer cations (such as Li+) into the layers, as clearly evidenced by EPR and FT-IR reflectance spectroscopies.

Gournis, D.; Mantaka-Marketou, A. E.; Karakassides, M. A.; Petridis, D.

349

Maps showing interpretation, using R-mode factor analysis, of trace-element abundances in heavy-mineral concentrate samples, Delta 1° x 2° Quadrangle, Utah  

USGS Publications Warehouse

A set of heavy-mineral concentrate data for the Delta 1° x 2° quadrangle, Utah Conterminous U.S. Mineral Assessment Program (CUSMAP) project was compiled from results of analyses of samples collected during the National Uranium Resource Evaluation Program (SURE), as well as results obtained from samples collected more recently by the USGS. Data results, sampling methods, and analytical methods are provided in Abrogast and others, 1993; 1990; 1988a; 1988b). A similar report, discussing results obtained from stream-sediment samples, is presented in Zimbelman (1993a). The Delta 1° x 2° quadrangle, Utah (figure 1) contains a variety of hydrothermal mineral deposit types, including porphyry-, vein-, replacement-, and Carlin-type deposits. These deposit types have been worked for commodities including gold, silver, beryllium, uranium, lead, zinc, copper, manganese, and cadmium (Lindsey, 1977; Morris and Mogensen, 1978; Zimbelman and others, 1990; Zimbelman and others, 1988). Heavy-mineral concentrate and stream-sediment samples derived from these hydrothermally altered rocks typically contain many geochemical anomalies (for example, see Zimbelman 1993b, c, d). Element associations characterizing lithology and hydrothermal mineral deposits can be distinguished using R-mode factor analysis. This tool often is useful in reconnaissance-scale surveys where sample anomalies are often weak. and single-element distributions may not help to delineate targets. R-mode factors analysis can help identify geologic trends and areas most likely to contain the mineral deposits. R-mode factor analysis was performed on a data set of results of analyses for 19 elements in 643 samples and produced a six-factor model. These six factors represent the geochemical contributions to the data set provided by lithologic and mineralization processes, The distribution of samples that contain high scores for mineralization-related factors is widespread in the Delta quadrangle. These sample sites are though to relate to both known prospect and mineralization areas, as well as define new areas that are geochemically favorable to contain altered or mineralized rocks.

Zimbelman, David R.

1994-01-01

350

Imprinted Clay Coil Vessels  

ERIC Educational Resources Information Center

The author teaches clay vessel construction in the fifth grade, and it is amazing what can be accomplished in one forty-five minute period when the expectations are clarified in the initial lesson. The author introduces clay coil vessels with a discussion of the sources of clay and how clay relates to fifth-grade science curriculum concepts such…

Lohr, Tresa Rae

2006-01-01

351

Clays in prebiological chemistry  

Microsoft Academic Search

Summary In this review an attempt is made to highlight the structures and properties of clay that may contribute to a better understanding of the role of clays in chemical evolution. 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 (glycine, aspartic acid,

M. Rao; D. G. Odom; J. Oró

1980-01-01

352

Rock Maker: an MS Excel™ spreadsheet for the calculation of rock compositions from proportional whole rock analyses, mineral compositions, and modal abundance  

NASA Astrophysics Data System (ADS)

Rock Maker is a simple software tool that computes bulk rock compositions resulting from mixing or unmixing of rocks or minerals. The calculations describe the chemical expression of processes such as magma mixing, fractional crystallization, assimilation, residual melt extraction, or formation of solid solutions. Rock Maker can also be used for the elimination of thermodynamically inactive or unwanted chemical components from the whole rock composition, such as cores of porphyroblasts that are considered not to be in equilibrium with the matrix. The calculation of the resulting rock composition is essentially based on modal proportions and compositions of different components in rocks, which may include specific portions of the rock or individual mineral phases. Compositional data, obtained using XRF, ICPMS, EDS, or EPMA, may include major and trace element concentrations. Depending upon the nature of the problem to be solved, the concentrations of oxidic and elemental components can be added to, or subtracted from, each other, producing the calculated normalized whole rock composition after completion of the investigated process (mixing, unmixing, depletion, enrichment, etc.). Furthermore, the software allows the calculation of whole rock compositions from ideal mineral compositions, for which modal proportions can be chosen from pre-defined mineral compositions. The data set includes the most common rock forming minerals and allows the addition of further phases. This section can be used to calculate the approximate whole rock compositions from petrographic modal analysis. This part of Rock Maker is specifically suitable as a teaching tool that illustrates the interrelationship between mineral compositions, modes, and the corresponding whole rock compositions.

Büttner, Steffen H.

2012-01-01

353

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

E-print Network

molecules connected to clay surfaces by van der Waals interactions. The high stability of the bonds formed materials. Keywords: organic molecules, carboxylic acids, clays, sorption, organic matter, preservation to investigate the role of clay minerals in organic matter preservation, the fixation of pure organic compounds

354

Ion-exchange reactions on clay minerals coupled with advection/dispersion processes. Application to Na+/Ca2+ exchange on vermiculite: Reactive-transport modeling, batch and stirred flow-through reactor experiments  

NASA Astrophysics Data System (ADS)

The present study aims at testing the validity of using an Na+/Ca2+ ion-exchange model, derived from batch data to interpret experimental Ca2+-for-Na+ exchange breakthrough curves obtained on vermiculite (a common swelling clay mineral in surface environments). The ion-exchange model was constructed considering the multi-site nature of the vermiculite surface as well as the exchange of all aqueous species (Mg2+ derived from the dissolution of the solid and H+). The proposed ion-exchange model was then coupled with a transport model, and the predicted breakthrough curves were compared with the experimental ones obtained using a well stirred flow-through reactor. For a given solute residence time in the reactor (typically 50 min), our thermodynamic model based on instantaneous equilibrium was found to accurately reproduce several of the experimental breakthrough curves, depending on the Na+ and Ca2+ concentrations of the influents pumped through the reactor. However the model failed to reproduce experimental breakthrough curves obtained at high flow rates and low chemical gradient between the exchanger phase and the solution. An alternative model based on a hybrid equilibrium/kinetic approach was thus used and allowed predicting experimental data. Based on these results, we show that a simple parameter can be used to differentiate between thermodynamic and kinetic control of the exchange reaction with water flow. The results of this study are relevant for natural systems where two aquatic environments having contrasted chemistries interact. Indeed, the question regarding the attainment of a full equilibrium in such a system during the contact time of the aqueous phase with the particle/colloid remains most often open. In this context, we show that when a river (a flow of fresh water) encounters marine colloids, a systematic full equilibrium can be assumed (i.e., the absence of kinetic effects) when the residence time of the solute in 1 m3 of the system is ?6200 h.

Tertre, E.; Hubert, F.; Bruzac, S.; Pacreau, M.; Ferrage, E.; Prêt, D.

2013-07-01

355

Seaweed minerals as nutraceuticals.  

PubMed

Seaweed is known as an abundant source of minerals. Mineral composition of seaweed is very changeable because of many exogenous and endogenous factors and differs also within the same species. Principally, seaweed is an excellent source of some essential elements. Mainly, iron and iodine are in high concentration. Seaweeds could be prospective as functional foods and also producers of mineral nutraceuticals. PMID:22054962

Mišurcová, Ladislava; Mach?, Ludmila; Orsavová, Jana

2011-01-01

356

Common clay and shale  

USGS Publications Warehouse

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.

Virta, R.L.

2011-01-01

357

A cids as chemical stabilizers of clay soils  

Microsoft Academic Search

Summary 1. In the acid stabilization of clay soils the aluminosilicate nucleus of the clay minerals is attacked. This process is accompanied by the escape of primarily the aluminum ion from the crystal lattice and the formation of depolymerized silicic acid. As the acid medium is neutralized to pH>3, the latter is condensed into an acid, highly hydrated silica gel,

V. E. Sokolovich

1973-01-01

358

Mineralogy and geochemistry of the clay fraction of till in northern Finland  

NASA Astrophysics Data System (ADS)

The mineralogy and geochemistry of the clay fraction of till in different moraine types and in different bedrock areas in northern Finland have been studied. Moraine types include ground moraine, Rogen moraine, Pulju moraine, Sevetti moraine and Kianta moraine. The bedrock is composed of granite, granite gneiss and mafic volcanite. X-ray diffraction, differential thermal and thermogravimetric analyses, transmission electron microscopy, X-ray fluorescence and atomic absorption spectrometry were used as analytical methods. Quartz, feldspars and amphibole are the primary rock-forming minerals occurring in nearly all the samples of each study area. The clay minerals proper include kaolinite, vermiculite, swelling-lattice vermiculite, chlorite, illite and mixed-layer minerals. Kaolinite occurs most abundantly only in till in the Kittiläarea, where a preglacial weathering crust has been the source rock. Poorly crystalline or amorphous Fe oxides also abound in till at Kittilä. Sodium, Ca and Si have been depleted and Al, Mg, Fe, K, Ti, P and trace elements have been enriched in the clay fraction compared with the fine fraction. The contents of Si, K and Na are higher in the granitic areas and the contents of Cu, Co, Ni and Zn are higher in the mafic volcanite areas. Preglacial weathering has led to the depletion of Si, Mg, Ca, K and Na and to the enrichment of Al, Fe, Ti, P and trace elements in the clay fraction of till in the Kittiläarea. High base metal values in the Inari area suggest the possibility of sulphide mineralizations there and high As values in the Kittiläarea indicate Au potential there. The most important factors controlling the mineralogical and geochemical composition of the clay fraction of the tills in northern Finland are the composition of the bedrock and the possible occurrence of an old weathering crust. The final grain size composition of the tills and consequently the quantitative proportions of the different minerals are often related to the last glacial quarrying and sorting processes; therefore the mineralogical composition of the tills is to a certain extent bound also to the respective moraine types.

Peuraniemi, Vesa; Aario, Risto; Pulkkinen, Pekka

1997-07-01

359

Chemical reactions of organic compounds on clay surfaces.  

PubMed Central

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

Soma, Y; Soma, M

1989-01-01

360

Spectral variability of plagioclase-mafic mixtures (2): Investigation of the optical constant and retrieved mineral abundance dependence on particle size distribution  

NASA Astrophysics Data System (ADS)

Remote sensing data reveal the presence of several igneous-rock forming silicates on the surfaces of various Solar System bodies. Mafic (Mg-Fe silicates) materials were clearly recognized in the past on Mars, Moon, Vesta, and recently the weak absorption of plagioclase has been detected on the lunar highland. The advance in the detection of these important mineral phases encourages the improvement in our capability to quantify the contribution of single end-members in mixed materials.

Carli, C.; Ciarniello, M.; Capaccioni, F.; Serventi, G.; Sgavetti, M.

2014-06-01

361

Using Natural Clays and Spent Bleaching Clay as Cheap Adsorbent for the Removal of Phenol in Aqueous Media  

E-print Network

Abstract-- Clay samples of six different locations of Kurdistan region were characterized. Chemical compositions of the clays were found using XRF technique for the clay powders. The mineralogy of the samples by XRD shows that the clay samples are mostly mixed layer type of Chlorite/Smectite composition with different types and quantities of mineral impurities. Specific surface area (SSA) and cation exchange capacity (CEC) for the clay samples were determined by methylene blue adsorption method. Although the de-oiled spent clays have less SSA and CEC compared with their virgin samples, but their adsorption efficiency is 70-80 % higher than their virgin clays due to the increase in the organophilic character of the de-oiled spent clays, while acid activation of the natural clays has no significant effect on the adsorption efficiency. Charcoal, the universal adsorbent, has removed 58 % of 50 ppm phenol solution, while de-oiled spent clays have removed 80-95 % of the phenol concentration. Index Term-- removal of phenol, de-oiling of clay, spent bleaching clay, adsorption efficiency. I.

unknown authors

362

Natural Radioactivity of Boron Added Clay Samples  

SciTech Connect

Clay, consisting fine-grained minerals, is an interesting materials and can be used in a variety of different fields especially in dermatology application. Using clay such a field it is important to measure its natural radioactivity. Thus the purpose of this study is to measure {sup 226}Ra, {sup 232}Th and {sup 40}K 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''x3'' NaI(Tl) detector. From the measured activity the radium equivalent activities (Ra{sub eq}), external hazard index (H{sub ex}), absorbed dose rate in air (D) and annual effective dose (AED) have also been obtained.

Akkurt, I.; Guenoglu, K. [Sueleyman Demirel University, Faculty of Arts and Sciences, Dept. of Physics, Isparta (Turkey); Canakcii, H. [Gaziantep University, Engineering Faculty, Civil Engineering Dept., Gaziantep (Turkey); Mavi, B. [Amasya University, Faculty of Arts and Sciences, Dept. of Physics, Amasya (Turkey)

2011-12-26

363

ADSORPTION OF BACTERIOPHAGES ON CLAY MINERALS  

EPA Science Inventory

Theability to predict the fate of microorganisms in soil is dependent on an understanding of the process of their sorption on soil and subsurface materials. Presently, we have focused on studying the thermodynamics of sorption of bacteriophages (T-2, MS-2, and...

364

Role of impact excavation in distributing clays over Noachian surfaces  

E-print Network

Role of impact excavation in distributing clays over Noachian surfaces C. J. Barnhart1 and F. Nimmo abundant in the crater wall and rim and less so in distal ejecta. Citation: Barnhart, C. J., and F. Nimmo

Nimmo, Francis

365

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

E-print Network

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, ...

Garimella, Sarvesh

2014-01-01

366

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

E-print Network

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, ...

Garimella, Sarvesh

367

Workability test method for metals applied to examine a workability measure (plastic limit) for clays  

Microsoft Academic Search

The Küre clay (KC) and the Deresakar? clay (DC), taken from the Sö?üt region (Bilecik, Turkey), were examined by chemical analysis, X-ray diffraction (XRD) and thermal analysis techniques. It was determined that the KC and DC, whose basic clay mineral was kaolinite, contained 37% and 66% free quartz as mass percentage, respectively. The compression and upset tests applied to metals

B. Baran; T. Ertürk; Y. Sar?kaya; T. Alemdaro?lu

2001-01-01

368

Mineral Commodities  

NSDL National Science Digital Library

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.

Perkins, Dexter

369

Communicating with Clay.  

ERIC Educational Resources Information Center

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)

Skophammer, Karen

2000-01-01

370

The distribution of secondary mineral phases along an eroding hillslope and its effect on carbon stabilization mechanisms and the fate of soil carbon fractions  

NASA Astrophysics Data System (ADS)

Soil redistribution processes can change soil carbon (C) dynamics drastically by moving carbon from high decomposition and re-sequestration environments at the eroding hillslope to low decomposition and burial at the depositional footslope and valley basin. This leads to not only spatially diverse soil carbon storage throughout the landscape, but also to qualitative changes of the transported carbon and the mineral phase. The interaction between those parameters and the effect on stabilization mechanisms for soil C are still a matter of debate. Here, we present an analysis that aims to clarify the bio/geo-chemical and mineralogical components involved in stabilizing C at various depths along an eroding cropped slope and how this affects the abundance of microbial derived carbon. We use the results of an incubation experiment combined with the abundance of amino sugars in different isolated soil C fractions as a tracer for the stability of the respective fraction. We applied further (i) a sequential extraction of the reactive soil phase using pyrophosphate, oxalate and dithionite-citrate-bicarbonate, and (ii) a qualitative analysis of the clay mineralogy, to analyze the changes in the mineral phase for the different isolated fractions along the slope transect. Our results emphasize the importance of physical protection within microaggregates to stabilize buried, chemically labile C. Our data further indicates that the stability of these aggregates is related to the presence of organo-mineral associations and poorly crystalline minerals. However, decreasing contents of these minerals with depth indicate a temporal limitation of this stabilization mechanism. Non-expandable clay minerals experience a relative enrichment at the depositional site while expandable clay minerals experience the same at the eroding site. These changes in clay mineralogy along the slope are partly responsible for the abundance of silt and clay associated C and the effectiveness of the clay fractions to stabilize C. In summary, our data clearly show that a variety of stabilization mechanisms together with changes in the organic and the mineral phase of soils need to be considered to understand this highly dynamic environment.

Doetterl, Sebastian; Cornelis, Jean-Thomas; Opfergelt, Sophie; Boeckx, Pascal; Bodé, Samuel; Six, Johan; Van Oost, Kristof

2014-05-01

371

Frictional strength and the effective pressure law of montmorillonite and illite clays  

Microsoft Academic Search

Abstract Low-strength clay minerals are a common constituent of fault gouges, and are often cited as a possible explanation for the low ambient shear stresses along the San Andreas fault inferred from heat flow constraints and in situ stress measurements. Montmorillonite, the weakest of the clay minerals, undergoes a gradual phase transition to illite with depth. In order to compare

C. Morrow; B. Radney; J. D. Byerlee

1992-01-01

372

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

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.

Pierson, C.T.; Spirakis, C.S.; Robertson, J.F.

1983-01-01

373

Coal cleaning residues and Fe-minerals implications.  

PubMed

In the present investigation, a study was undertaken to understand the origin of Fe-minerals presents in Brazilian coal mining and to understand the environmental implication and the chemical heterogeneity in the study area. Coal cleaning residue samples rich in clays, quartz, sulphides, carbonates, sulphates, etc. were sampled from Lauro Muller, Urussanga, Treviso, Siderópolis, and Criciúma cities in the Santa Catarina State and a total of 19 samples were collected and Mössbauer, XRD, SEM/EDX, and TEM analyses were conducted on the samples. The major Fe-minerals identified are represented by the major minerals chlorite, hematite, illite, and pyrite, while the minor minerals include, ankerite, chalcopyrite, goethite, hematite, jarosite, maghemite, magnetie, marcasite, melanterite, natrojarosite, oligonite, pyrrhotite, rozenite, schwertmannite, siderite, and sideronatrile. Pyrite is relatively abundant in some cases, making up to around 10% of the mineral matter in several samples. The sulphates minerals such as jarosite and others, probably represent oxidation products of pyrite, developed during exposure or storage. PMID:20127406

Silva, Luis F O; Macias, Felipe; Oliveira, Marcos L S; da Boit, M Kátia; Waanders, Frans

2011-01-01

374

Soil clay content underlies prion infection odds  

PubMed Central

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. PMID:21326232

David Walter, W.; Walsh, Daniel P.; Farnsworth, Matthew L.; Winkelman, Dana L.; Miller, Michael W.

2011-01-01

375

Soil clay content underlies prion infection odds  

USGS Publications Warehouse

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.

David, Walter W.; Walsh, D.P.; Farnsworth, M.L.; Winkelman, D.L.; Miller, M.W.

2011-01-01

376

What makes a natural clay antibacterial?  

PubMed

Natural clays have been used in ancient and modern medicine, but the mechanism(s) that make certain clays lethal against bacterial pathogens has not been identified. We have compared the depositional environments, mineralogies, and chemistries of clays that exhibit antibacterial effects on a broad spectrum of human pathogens including antibiotic resistant strains. Natural antibacterial clays contain nanoscale (<200 nm), illite-smectite and reduced iron phases. The role of clay minerals in the bactericidal process is to buffer the aqueous pH and oxidation state to conditions that promote Fe(2+) solubility. Chemical analyses of E. coli killed by aqueous leachates of an antibacterial clay show that intracellular concentrations of Fe and P are elevated relative to controls. Phosphorus uptake by the cells supports a regulatory role of polyphosphate or phospholipids in controlling Fe(2+). Fenton reaction products can degrade critical cell components, but we deduce that extracellular processes do not cause cell death. Rather, Fe(2+) overwhelms outer membrane regulatory proteins and is oxidized when it enters the cell, precipitating Fe(3+) and producing lethal hydroxyl radicals. PMID:21413758

Williams, Lynda B; Metge, David W; Eberl, Dennis D; Harvey, Ronald W; Turner, Amanda G; Prapaipong, Panjai; Poret-Peterson, Amisha T

2011-04-15

377

Rocks and Minerals  

NSDL National Science Digital Library

This unit provides younger students with an introduction to rocks and minerals. Topics include the definition of a mineral, the physical properties of minerals and how they are measured, and a discussion of quartz, the most basic silicate mineral and one of the most abundant minerals in the Earth's crust. The discussion on rocks includes the rock cycle, the three rock types (igneous, sedimentary, metamorphic), and how they are formed. There is also a vocabulary list and downloadable, printable worksheets for each major topic.

Medina, Philip

2010-09-08

378

Modified clay sorbents  

DOEpatents

A novel modified clay sorbent and method of treating industrial effluents to remove trace pollutants, such as dioxins, biphenyls, and polyaromatics such as benzo(a)pyrene and pentachlorophenol. The novel clay sorbent has a composite structure in which the interlayer space of an expandable clay, such as smectite, is filled with polyvalent or multivalent inorganic cations which forces weaker surfactant cations to locate on the surface of the clay in such an orientation that the resulting composite is hydrophilic in nature. A specific example is cetylpyridinium-hydroxy aluminum-montmorillonite. In certain embodiments, a non-expanding clay, such as kaolinite, is used and surfactant cations are necessarily located on an external surface of the clay. A specific example is cetylpyridinium-kaolinite.

Fogler, H. Scott (Ann Arbor, MI); Srinivasan, Keeran R. (Livonia, MI)

1990-01-01

379

The influence of authigenic clay formation on the mineralogy and stable isotopic record of lacustrine carbonates  

NASA Astrophysics Data System (ADS)

The mineralogical, compositional and stable isotopic variability of lacustrine carbonates are frequently used as proxies for ancient paleoenvironmental change in continental settings, under the assumption that precipitated carbonates reflect conditions and chemistry of ancient lake waters. In some saline and alkaline lake systems, however, authigenic clay minerals, forming at or near the sediment water interface, are a major sedimentary component. Often these clays are rich in Mg, influencing the geochemical budget of lake waters, and are therefore expected to influence the properties of contemporaneous authigenic carbonate precipitates (which may also contain Mg). This paper documents evidence for a systematic feedback between clay mineral and carbonate authigenesis through multiple precessionally driven, m-scale sedimentary cycles in lacustrine oil-shale deposits of the Eocene Green River Formation from the Uinta Basin (NE Utah). In the studied section, authigenic, Mg-rich, trioctahedral smectite content varies cyclically between 9 and 39 wt.%. The highest concentrations occur in oil-shales and calcareous mudstones deposited during high lake level intervals that favored sedimentary condensation, lengthening the time available for clay diagenesis and reducing dilution by other siliciclastic phases. An inverse relation between dolomite percentage of carbonate and trioctahedral smectite abundance suggests the Mg uptake during clay authigenesis provides a first order control on carbonate mineralogy that better explains carbonate mineralogical trends than the possible alternative controls of (1) variable Mg/Ca ratios in lake water and (2) degree of microbial activity in sediments. We also observe that cyclical change in carbonate mineralogy, believed to be induced by clay authigenesis, also causes isotopic covariation between ?13CPDB and ?18OPDB of bulk sediments because of differences in the equilibrium fractionation factors of dolomite and calcite (˜2‰ and ˜2.6%, respectively). This provides an alternative mechanism for the common pattern of isotopic covariation, which is typically attributed to the effect of simultaneous changes in water balance and biological activity on the carbon and oxygen isotopic composition of lake waters. These findings may help improve paleoenvironmental reconstructions based on lacustrine carbonate records by adding to the factors known to influence the mineralogical, compositional and stable isotopic signals recorded by lacustrine carbonates.

Bristow, Thomas F.; Kennedy, Martin J.; Morrison, Keith D.; Mrofka, David D.

2012-08-01

380

Modeling Oil-Mineral Interactions Sungu Hwang, Mario Blanco, and William A. Goddard, III  

E-print Network

Modeling Oil-Mineral Interactions Sungu Hwang, Mario Blanco, and William A. Goddard, III Materials 1 #12;Objectives Forcefield development of calcite and clay minerals Mineral - water, and mineral - chemicals interactions The adsorption of chemicals on minerals The atomistic simulation of the minerals

Goddard III, William A.

381

The role of reaction affinity and secondary minerals in regulating chemical weathering rates at the Santa Cruz Soil Chronosequence, California  

USGS Publications Warehouse

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 t