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Sample records for chlorites

  1. Diagenetic Chlorite

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari; Friis, Henrik; Hansen, Jens Peter Vind

    2013-01-01

    hydrocarbon seal, and our study demonstrates the influence of early diagenetic quartz on the formation of the chlorite seal. Early opal and microquartz are precipitated close to shale contacts and prevent the interaction between abundant detrital glaucony and pore-fluid and thus the formation of grain...

  2. Experimental determination of chlorite dissolution rates

    International Nuclear Information System (INIS)

    Current concepts of the geological disposal of low- and intermediate-level radioactive wastes in the UK envisage the construction of a mined facility (incorporating cementitious engineered barriers) in chlorite-bearing rocks. To model accurately the fluid-rock reactions within the disturbed zone surrounding a repository requires functions that describe mineral dissolution kinetics under pH conditions that vary from near neutral to highly alkaline. Therefore, an experimental study to determine the dissolution rates of Fe-rich chlorite has been undertaken as part of the Nirex Safety Assessment Research Program. Four experiments have been carried out at 25 C and four at 70 C, both sets using a range of NaCl/NaOH solutions of differing pH (of nominal pH 9.0, 10.3, 11.6 and 13.0 [at 25 C]). Dissolution rates have been calculated and were found to increase with increasing pH and temperature. However, increased pH resulted in non-stoichiometric dissolution possibly due to preferential dissolution of part of the chlorite structure relative to another, or reprecipitation of some elements as thin hydroxide or oxyhydroxide surface coatings on the chlorite. These results also show that chlorite dissolution is appreciably slower than that of albite and quartz at both 25 and 70 C, but slightly faster than that of muscovite at 70 C

  3. Methane oxidation linked to chlorite dismutation

    Science.gov (United States)

    Miller, Laurence G.; Baesman, Shaun M.; Carlström, Charlotte I.; Coates, John D.; Oremland, Ronald S.

    2014-01-01

    We examined the potential for CH4 oxidation to be coupled with oxygen derived from the dissimilatory reduction of perchlorate, chlorate, or via chlorite (ClO−2) dismutation. Although dissimilatory reduction of ClO−4 and ClO−3 could be inferred from the accumulation of chloride ions either in spent media or in soil slurries prepared from exposed freshwater lake sediment, neither of these oxyanions evoked methane oxidation when added to either anaerobic mixed cultures or soil enriched in methanotrophs. In contrast, ClO−2 amendment elicited such activity. Methane (0.2 kPa) was completely removed within several days from the headspace of cell suspensions of Dechloromonas agitata CKB incubated with either Methylococcus capsulatus Bath or Methylomicrobium album BG8 in the presence of 5 mM ClO−2. We also observed complete removal of 0.2 kPa CH4 in bottles containing soil enriched in methanotrophs when co-incubated with D. agitata CKB and 10 mM ClO−2. However, to be effective these experiments required physical separation of soil from D. agitata CKB to allow for the partitioning of O2 liberated from chlorite dismutation into the shared headspace. Although a link between ClO−2 and CH4 consumption was established in soils and cultures, no upstream connection with either ClO−4 or ClO−3 was discerned. This result suggests that the release of O2 during enzymatic perchlorate reduction was negligible, and that the oxygen produced was unavailable to the aerobic methanotrophs.

  4. Methane oxidation linked to chlorite dismutation.

    Directory of Open Access Journals (Sweden)

    Laurence G. Miller

    2014-06-01

    Full Text Available We examined the potential for CH4 oxidation to be coupled with oxygen derived from the dissimilatory reduction of perchlorate, chlorate or via chlorite (ClO2- dismutation. Although dissimilatory reduction of ClO4- and ClO3- could be inferred from the accumulation of chloride ions either in spent media or in soil slurries prepared from exposed freshwater lake sediment, neither of these oxyanions evoked methane oxidation when added to either anaerobic mixed cultures or soil enriched in methanotrophs. In contrast, ClO2- amendment elicited such activity. Methane (0.2 kPa was completely removed within several days from the headspace of cell suspensions of Dechloromonas agitata CKB incubated with either Methylococcus capsulatus Bath or Methylomicrobium album BG8 in the presence of 5 mM ClO2-. We also observed complete removal of 0.2 kPa CH4 in bottles containing soil enriched in methanotrophs when co-incubated with D. agitata CKB and 10 mM ClO2-. However, to be effective these experiments required physical separation of soil from D. agitata CKB to allow for the partitioning of O2 liberated from chlorite dismutation into the shared headspace. Although a link between ClO2- and CH4 consumption was established in soils and cultures, no upstream connection with either ClO4- or ClO3- was discerned. This result suggests that the release of O2 during enzymatic perchlorate reduction was negligible, and that the oxygen produced was unavailable to the aerobic methanotrophs.

  5. Sensitivity of antioxidant-deficient yeast to hypochlorite and chlorite.

    Science.gov (United States)

    Kwolek-Mirek, Magdalena; Bartosz, Grzegorz; Spickett, Corinne M

    2011-08-01

    Sodium hypochlorite and sodium chlorite are commonly used as disinfectants, and understanding the mechanisms of microbial resistance to these compounds is of considerable importance. In this study, the role of oxidative stress and antioxidant enzymes in the sensitivity of the yeast Saccharomyces cerevisiae to hypochlorite and chlorite was studied. Yeast mutants lacking Cu-Zn superoxide dismutase, but not mutants deficient in cytoplasmic and peroxisomal catalase, were hypersensitive to the action of both hypochlorite and chlorite. Both compounds depleted cellular glutathione, induced the production of reactive oxygen species and decreased the viability of the cells. The toxicity of hypochlorite and chlorite was abolished by hypoxic and anoxic conditions and ameliorated by thiol antioxidants and ascorbate. The results demonstrated that the action of hypochlorite and chlorite involves the formation of superoxide and peroxide and that SOD1 is protective, probably by limiting the formation of hydroxyl radicals and damage to proteins. PMID:21761455

  6. Removal of chlorite by reaction with ferrous iron

    OpenAIRE

    Iatrou, Angela

    1991-01-01

    The use of chlorine dioxide as an oxidant and/or disinfectant for drinking water treatment has been an alternative considered when utilities seek to control trihalomethane concentrations. However, concern regarding residual concentrations of chlorite and chlorate have resulted in limitations on applied chlorine dioxide dosages. This study describes the use of ferrous iron as a possible reducing agent for the elimination of residual chlorite from drinking water.

  7. Low-temperature magnetic anisotropy in micas and chlorite

    DEFF Research Database (Denmark)

    Biedermann, Andrea R.; Bender Koch, Christian; Lorenz, Wolfram E A;

    2014-01-01

    of magnetic susceptibility. Because diamagnetic and paramagnetic susceptibility are both linearly dependent on field, separation of the anisotropic contributions requires understanding how the degree of anisotropy of the paramagnetic susceptibility changes as a function of temperature. Note that diamagnetic...... of approximately 6.3-8.7 for individual samples of muscovite, phlogopite and chlorite on cooling from RT to 77 K and between 11.2 and 12.4 for biotite. A decrease in temperature enhances the paramagnetic anisotropy in a mineral. Biotite exhibits a relatively stronger enhancement due to the onset of magnetic......Phyllosilicates, such as micas and chlorite, are common rock-forming minerals and often show preferred orientation in deformed rocks. In combination with single-crystal anisotropy, this leads to anisotropy of physical properties in the rock, such as magnetic susceptibility. In order to effectively...

  8. Ligand Binding to Chlorite Dismutase from Magnetospirillum sp.

    Science.gov (United States)

    De Schutter, Amy; Correia, Hugo D; Freire, Diana M; Rivas, María G; Rizzi, Alberto; Santos-Silva, Teresa; González, Pablo J; Van Doorslaer, Sabine

    2015-10-29

    Chlorite dismutase (Cld) catalyzes the reduction of chlorite to chloride and dioxygen. Here, the ligand binding to Cld of Magnetospirillum sp. (MaCld) is investigated with X-ray crystallography and electron paramagnetic resonance (EPR). EPR reveals a large heterogeneity in the structure of wild-type MaCld, showing a variety of low- and high-spin ferric heme forms. Addition of an axial ligand, such as azide or imidazole, removes this heterogeneity almost entirely. This is in line with the two high resolution crystal structures of MaCld obtained in the presence of azide and thiocyanate that show the coordination of the ligands to the heme iron. The crystal structure of the MaCld-azide complex reveals a single well-defined orientation of the azide molecule in the heme pocket. EPR shows, however, a pH-dependent heme structure, probably due to acid-base transitions of the surrounding amino-acid residues stabilizing azide. For the azide and imidazole complex of MaCld, the hyperfine and nuclear quadrupole interactions with the close-by (14)N and (1)H nuclei are determined using pulsed EPR. These values are compared to the corresponding data for the low-spin forms observed in the ferric wild-type MaCld and to existing EPR data on azide and imidazole complexes of other heme proteins. PMID:26287794

  9. Kinetics of chlorite dismutase in a perchlorate degrading reactor sludge.

    Science.gov (United States)

    Nadaraja, Anupama Vijaya; Veetil, Prajeesh Gangadharan Puthiya; Vidyadharan, Athira; Bhaskaran, Krishnakumar

    2013-01-01

    Kinetics of chlorite dismutase (CD), the terminal enzyme involved in the perchlorate (ClO4(-)) reduction pathway, in a ClO4(-)-degrading bioreactor are reported in this study. Enzyme activity was determined from dissolved oxygen released during disproportionation of chlorite (ClO2(-)). CD activity was in the range 29.8-36.4 U/mg dry weight sludge, and kinetic constants Vmax and K(m) of the enzyme were 37.83 U/mg dry weight and 0.28 mM, respectively. Among reactor operational conditions, enzyme activity was observed at pH 4.0-9.0, with an optimum at pH 6.0. Redox potential in the range -50 to +120mV and NaCl up to 3.5 g/L had no significant effect on CD activity. However, co-occurring pollutants such as ammonium at 10 ppm, nitrite at 50 ppm and EDTA at 100 microM reduced CD activity substantially. The present study highlights ideal bioreactor conditions to avoid ClO2(-) toxicity, while indicating the buffering potential of a mixed microbial system against inhibiting factors to maintain stable CD activity in bioreactors.

  10. Approaches to the Low Grade Metamorphic History of the Karakaya Complex by Chlorite Mineralogy and Geochemistry

    Directory of Open Access Journals (Sweden)

    Sema Tetiker

    2015-04-01

    Full Text Available In this study, chlorite is used to investigate the diagenetic-metamorphic evolution and accurate geological history of the different units belonging to the Karakaya complex, Turkey. Primary and secondary chlorite minerals in the very low-grade metamorphic rocks display interference colors of blue and brown and an appearance of optical isotropy. Chlorites are present in the matrix, pores, and/or rocks units as platy/flaky and partly radial forms. X-ray diffraction (XRD data indicate that Mg-Fe chlorites with entirely IIb polytype (trioctahedral exhibit a variety of compositions, such as brunsvigite-diabantite-chamosite. The major element contents and structural formulas of chlorite also suggest these were derived from both felsic and metabasic source rocks. Trace and rare earth element (REE concentrations of chlorites increase with increasing grade of metamorphism, and these geochemical changes can be related to the tectonic structures, formational mechanics, and environments present during their generation.

  11. Diagenetic alteration process of chlorite in Tyr Member sandstone, Siri Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari; Friis, Henrik; Hansen, Jens Peter Vind

    quartz overgrowths, calcite and chlorite and also minor amount of diagenetic K-feldspar. The investigated materials were core samples of Palaeocene sands referred to the Ty Member from the well Rau 1A. Chlorite was formed as pervasive grain-coating cement, but much porosity was still present. In the oil...... zone and deeper, porous samples were later cemented by macro quartz, with larger amounts in the water zone. Chlorite is found in varying amounts in Rau 1A samples. It can be recognized in SEM as a platy or bladed precipitate, which is mostly rich in iron. Chlorite is present in most samples, although...... only in traceable amounts in the samples which are dominated by microquartz cement. There seem to be two chlorite phases: The first phase occurs as rosettes in a grain coating growth pattern. It is partially intergrown with microquartz or forms a dense mixture of small chlorite rosettes and scattered...

  12. Geochemistry of sericite and chlorite in well 14-2 Roosevelt Hot Springs geothermal system and in mineralized hydrothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Ballantyne, J.M.

    1980-06-01

    Chemical compositions of chlorite and sericite from one production well in the Roosevelt geothermal system have been determined by electron probe methods and compared with compositions of chlorite and sericite from porphyry copper deposits. Modern system sericite and chlorite occur over a depth interval of 2 km and a temperature interval of 250/sup 0/C.

  13. Approaches to the Low Grade Metamorphic History of the Karakaya Complex by Chlorite Mineralogy and Geochemistry

    OpenAIRE

    Sema Tetiker; Hüseyin Yalçın; Ömer Bozkaya

    2015-01-01

    In this study, chlorite is used to investigate the diagenetic-metamorphic evolution and accurate geological history of the different units belonging to the Karakaya complex, Turkey. Primary and secondary chlorite minerals in the very low-grade metamorphic rocks display interference colors of blue and brown and an appearance of optical isotropy. Chlorites are present in the matrix, pores, and/or rocks units as platy/flaky and partly radial forms. X-ray diffraction (XRD) data indicate that Mg-F...

  14. Sedimentary and diagenetic processes at the origin of chlorites formation inside silico-clastic reservoirs; Processus sedimentaires et diagenetiques a l'origine de la formation des chlorites dans les reservoirs silicoclastiques

    Energy Technology Data Exchange (ETDEWEB)

    Tinseau, E.

    2002-06-01

    Diagenetic chlorite in deeply buried petroleum reservoirs give to the formations relatively good reservoir properties. The purpose of this study is, by a multidisciplinary approach, to better understand how chlorites form and to put into evidence the factors which influence their formation. Four case studies have been chosen: the silici-clastic Mulichinco (Valanginian) and Tordillo (Kimmeridgian) formations of the Neuquen basin, Argentina, the Springhill Formation (Lower Cretaceous) of the Austral basin, Argentina, and the Mashirah Bay formation (Precambrian) from the Huqf-Haushi area, Oman. Sedimentological analyses have been combined to petrographical observations (optical microscope, SEM, TEM, HRTEM, Cathodoluminescence), to chemical analyses, to chlorite polytypicism study, and by fluid inclusions micro-thermometry in silicifications. These studies have allowed to precise the diagenetic sequence for each of these formations and to approach the conditions for the formation of diagenetic chlorites for each case, and to conclude the following points: (1) ferro-magnesian chlorites require precursor material such as volcano-clasts. Their presence is associated with continental environments. Their destabilization into chlorite, via smectite, is favoured at the water/sediment interface during marine transgression. (2) ferriferous chlorites formation can happen from glauconitic minerals which contain a 7 angstroms phase like berthierite, and 10-12 angstroms phase as smectite phase, under anoxic conditions. (3) polytypicism variations traduce two different mechanisms for the chlorite formation: ferro-magnesian chlorites form by dissolution-recrystallization process and re-equilibrate with burial, whereas ferriferous chlorite form from berthierite. (author)

  15. Chloritization and associated alteration at the Jabiluka unconformity-type uranium deposit, Northern Territory, Australia

    Science.gov (United States)

    Nutt, Constance J.

    1989-01-01

    Jabiluka is the largest of four known uncomformity-type uranium deposits that are hosted by brecciated and altered metasedimentary rocks in the Pine Creek geosyncline, Northern Territory, Australia. The alteration zone at Jabiluka is dominated by chlorite, but also contains white mica, tourmaline and apatite; hematite is present, but only in minor amounts. Added quartz is mainly restricted to fractures and breccias. Chlorite, which formed during episodic fluid movement, partly to totally replaced all pre-existing minerals. Chloritized rocks are enriched in Mg, and depleted in K, Ca, Na and Si. Five types of chlorite are optically and chemically distinguishable in the rocks at Jabiluka. Chloritization is proposed as a mechanism that lowered the pH of the circulating fluid, and also caused significant loss of silica from the altered rocks. The proposed constraints on alteration, and presumably on at least part of the uranium mineralization, neither require nor preclude the existence of the unconformity as necessary for the formation of ore.

  16. Characteristics of chlorites in seismogenic fault zones: the Taiwan Chelungpu Fault Drilling Project (TCDP core sample

    Directory of Open Access Journals (Sweden)

    Y. Hashimoto

    2007-07-01

    Full Text Available The iron content and the asymmetry of iron and magnesium ions in chlorites are examined for the Chelungpu Fault in Taiwan, which is a seismogenic fault. The samples are collected from the cores drilled for the Taiwan Chelungpu Fault Drilling Project (TCDP. Three fault zones are recognized as candidates for the source of seismogenic materials. The fault zones are composed of fractured-damaged rocks, breccia, gray gouge, black gouge, and black material. Chlorite from each type of rock was analyzed by using X-ray diffraction (XRD. The iron content and asymmetry of the iron and magnesium ions in the chlorites were estimated from the XRD peak ratios. The hydroxide and silicate layers in the black gouge and black material have low iron contents. Many studies have suggested that a temperature rise occurred at the fault zones. In addition, the temperature rise can result in the production of iron oxides such as magnetite or maghemite, as reported by other studies. However, the temperature rise cannot explain the low value of iron content in the chlorites. Another reason for the low value of iron content is the variation in the pH of the fluid, which can be controlled by radical reactions. Therefore, the reactions at the seismogenic fault are due to not only the thermal decomposition resulting from the temperature rise and but also rock-fluid interactions based on the chlorite characteristics.

  17. Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges.

    Science.gov (United States)

    Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis

    2016-05-01

    Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10(-3) S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10(-1) S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front.

  18. Modeling of Turing Structures in the Chlorite-Iodide-Malonic Acid-Starch Reaction System

    Science.gov (United States)

    Lengyel, Istivan; Epstein, Irving R.

    1991-02-01

    Recent experiments on the chlorite-iodide-malonic acid-starch reaction in a gel reactor give the first evidence of the existence of the symmetry breaking, reaction-diffusion structures predicted by Turing in 1952. A five-variable model that describes the temporal behavior of the system is reduced to a two-variable model, and its spatial behavior is analyzed. Structures have been found with wavelengths that are in good agreement with those observed experimentally. The gel plays a key role by binding key iodine species, thereby creating the necessary difference in the effective diffusion coefficients of the activator and inhibitor species, iodide and chlorite ions, respectively.

  19. THE REACTIVITY OF PREHYDROLYZED SOFTWOOD KRAFT PULPS AFTER PROLONGED COOKING FOLLOWED BY CHLORITE DELIGNIFICATION

    Directory of Open Access Journals (Sweden)

    Ulf Germgard

    2011-05-01

    Full Text Available In a laboratory study high-quality spruce chips were prehydrolyzed to remove hemicelluloses and then kraft cooked to different kappa numbers by varying the cooking time. Each pulp sample was then chlorite delignified to selectively remove the remaining lignin. The reactivities of the pulp samples before and after chlorite delignification were determined by Fock’s test, which is supposed to measure the pulp’s reactivity in the conventional viscose process. A number of analyses were carried out to determine which parameters affected pulp reactivity, as, for example: intrinsic viscosity, kappa number, pulp yield, carbohydrate composition, levelling-off degree of polymerization (LODP, and alkali solubility. The results of the study showed that the pulp reactivity increased with decreasing kappa number, and the highest reactivity was obtained after total lignin removal using chlorite delignification. It was also found that the carbohydrate composition had no influence on the pulp reactivity, but lower intrinsic viscosity either obtained by prolonged cooking or chlorite delignification correlated with higher pulp reactivity. Finally, lower alkali solubility, i.e. higher R18, reduced the reactivity.

  20. Influence of drinking water treatments on chlorine dioxide consumption and chlorite/chlorate formation.

    Science.gov (United States)

    Sorlini, Sabrina; Gialdini, Francesca; Biasibetti, Michela; Collivignarelli, Carlo

    2014-05-01

    Disinfection is the last treatment stage of a Drinking Water Treatment Plant (DWTP) and is carried out to maintain a residual concentration of disinfectant in the water distribution system. Chlorine dioxide (ClO2) is a widely used chemical employed for this purpose. The aim of this work was to evaluate the influence of several treatments on chlorine dioxide consumption and on chlorite and chlorate formation in the final oxidation/disinfection stage. A number of tests was performed at laboratory scale employing water samples collected from the DWTP of Cremona (Italy). The following processes were studied: oxidation with potassium permanganate, chlorine dioxide and sodium hypochlorite, coagulation/flocculation with ferric chloride and aluminum sulfate, filtration and adsorption onto activated carbon. The results showed that the chlorine dioxide demand is high if sodium hypochlorite or potassium permanganate are employed in pre-oxidation. On the other hand, chlorine dioxide leads to the highest production of chlorite and chlorate. The coagulation/flocculation process after pre-oxidation shows that chlorine dioxide demand decreases if potassium permanganate is employed as an oxidant, both with ferric chloride and aluminum sulfate. Therefore, the combination of these processes leads to a lower production of chlorite and chlorate. Aluminum sulfate is preferable in terms of the chlorine dioxide demand reduction and minimization of the chlorite and chlorate formation. Activated carbon is the most effective solution as it reduced the chlorine dioxide consumption by about 50% and the DBP formation by about 20-40%.

  1. Mineralogy and geochemistry of laterites developed on chlorite schists in Tchollire region, North Cameroon

    Science.gov (United States)

    Banakeng, L. A.; Zame, P. Zo'o.; Tchameni, R.; Mamdem, L.; Bitom, D.

    2016-07-01

    Laterites developed from the weathering of chlorite schists have been studied in Tchollire region, North Cameroon. They include two profiles: a 5.5 m depth profile in Doudja site and a 12.3 m profile in Fimbe site. The chlorite schists have a lepidoblastic to lepidogranoblastic texture and are mainly composed of chlorite, muscovite, biotite, feldspars and quartz but that of Fimbe is marked by the presence of amphibole. It is felsic with a high SiO2 content (67%) and low Fe2O3 (5.8%) and MgO (2.4%) contents in Doudja site but has a lower content of SiO2 (46%) in the Fimbe site where it is mafic with higher contents in Fe2O3 (12.4%) and MgO (6.3%). The chlorite schists of Doudja show high contents in Zr, Sr, Ta, with moderate contents in Cr, V, U and Zn. That of Fimbe is particularly rich in Cr, V, Ni, Sr and Zn with a moderate Zr content. All chlorite schists have high barium contents (270-393 ppm) with LREE-enrichment. The soils are yellowish and, from bottom to top, are composed of a coarse saprolite, fine saprolite, loose clayey horizon and an organo mineral horizon. The main minerals are chlorite, muscovite, biotite, feldspars, quartz, smectites, vermiculite, kaolinite, hematite and goethite. In Doudja, SiO2 mainly decreases from the bottom to the top of the profile while, Al2O3 and Fe2O3 generally increase; in Fimbe, SiO2 and Al2O3 increase up the profile but Fe2O3 decreases; the general high Fe and corresponding decrease in Mg contents in the soils show that the smectite formed is nontronite. Chromium, V, Cu, Ba and Sr show high contents in the two studied profiles but Zr, U and Ta is higher in Doudja than in Fimbe. Copper generally has high contents in the loose clayey and organo mineral horizons. Nickel is higher in the Fimbe profile and probably issued from the Ni-rich mafic protolith. SiO2 has positive correlations with K2O, Zr, Li and Rb. Correlations of SiO2 with CaO, TiO2 and Cr are negative. Al2O3 and Fe2O3 have a positive correlation with Pb. Doudja

  2. Evaluation of experimental teat dip containing sodium chlorite and lactic acid by excised teat assay.

    Science.gov (United States)

    Schmidt, A L; Oliver, S P; Fydenkevez, M E

    1984-12-01

    An experimental teat dip containing sodium chlorite and lactic acid, diluted in water, was evaluated by excised teat protocol. The teat dip was tested against 21 microorganisms. Included were: Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Numerous strains were tested for strain differences. Environmental bacteria were included because of their increasing importance as a cause of bovine mastitis. All excised teats were dipped in a bacterial suspension containing about 1 X 10(8) cfu/ml. Negative control teats were not dipped in a germicidal compound. Positive controls were dipped in 1% iodophor. Effectiveness of the experimental teat dip was expressed as the percent reduction in mean log of bacteria recovered from dipped teats as compared to numbers recovered from control teats. The sodium chlorite - lactic acid dip caused a greater percent log reduction than iodophor for 14 of 21 strains tested. However, differences were generally slight. The experimental teat dip appeared effective against Gram-negative bacteria. Some differences in percent log reduction were observed between strains of the same species. Lowest effectiveness and greatest strain variation were observed with Staphylococcus aureus for both dips tested. PMID:6530497

  3. Dissimilatory perchlorate reduction linked to aerobic methane oxidation via chlorite dismutase

    Science.gov (United States)

    Oremland, R. S.; Baesman, S. M.; Miller, L. G.

    2013-12-01

    The presence of methane (CH4) in the atmosphere of Mars is controversial yet the evidence has aroused scientific interest, as CH4 could be a harbinger of extant or extinct microbial life. There are various oxidized compounds present on the surface of Mars that could serve as electron acceptors for the anaerobic oxidation of CH4, including perchlorate (ClO4-). We examined the role of perchlorate, chlorate (ClO3-) and chlorite (ClO2-) as oxidants linked to CH4 oxidation. Dissimilatory perchlorate reduction begins with reduction of ClO4- to ClO2- and ends with dismutation of chlorite to yield chloride (Cl-) and molecular oxygen (O2). We explored the potential for aerobic CH4 oxidizing bacteria to couple with oxygen derived from chlorite dismutation during dissimilatory perchlorate reduction. Methane (0.2 kPa) was completely removed within several days from the N2-flushed headspace above cell suspensions of methanotrophs (Methylobacter albus strain BG8) and perchlorate reducing bacteria (Dechloromonas agitata strain CKB) in the presence of 5 mM ClO2-. Similar rates of CH4 consumption were observed for these mixed cultures whether they were co-mingled or segregated under a common headspace, indicating that direct contact of cells was not required for methane consumption to occur. We also observed complete removal of 0.2 kPa CH4 in bottles containing dried soil (enriched in methanotrophs by CH4 additions over several weeks) and D. agitata CKB and in the presence of 10 mM ClO2-. This soil (seasonally exposed sediment) collected from the shoreline of a freshwater lake (Searsville Lake, CA) demonstrated endogenous CH4 uptake as well as perchlorate, chlorate and chlorite reduction/dismutation. However, these experiments required physical separation of soil from the aqueous bacterial culture to allow for the partitioning of O2 liberated from chlorite dismutation into the shared headspace. Although dissimilatory reduction of ClO4- and ClO3- could be inferred from the

  4. Evolution of chlorite composition in the Paleogene prototype basin of Jiyang Depression, Shandong, China, and its implication for paleogeothermal gradient

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Ming; CHEN; XiaoMing; JI; JunFeng; ZHANG; Zhe; ZHANG; Yun

    2007-01-01

    The Dongying Basin,Huimin Basin,and Zhanhua Basin constitute the Jiyang Depression in Shandong Province.They are major oil and gas exploring districts within the depression.Through reconstructions of the paleotemperature of the three basins facilitated with the chlorite geothermometry,the thermal history of the Paleogene prototype basin in Jiyang Depression and its geologic significance were explored.This study reveals that the Si4+ component in chlorites reduces gradually as its buried depth increases,while the AlIV component increases accordingly.The chlorite type changes from silicon-rich diabantite to silicon-poor ferroamesite and prochlorite.The prochlorite in this district only appears in the deep buried depth,high temperature,and relatively old stratigraphies; while the diabantite appears in the shallower buried,low temperature,and newly formed strata; the ferroamesite exists in the conditions between prochlorite and diabantite formation.The diagenetic temperatures of the chlorites in these Paleogene basins are 171―238℃ for the Dongying Basin,160―202℃ for the Huimin Basin,and 135―180℃ for the Zhanhua Basin.The differences of the chlorite diagenetic temperatures in the three basins were controlled by the duration time of the structural depressing processes.Higher temperature indicates longer depression time.The relationship between the chlorite diagenetic temperature and its buried depth indicates that the average paleogeothermal gradient is about 38.3℃/km in the Paleogene prototype basin of Jiyang Depression.It was higher than the present geothermal gradient (29―30℃/km).This phenomenon was attributed to the evolution of the structural dynamics in the depression basin.

  5. Enhancement of the nanofibrillation of wood cellulose through sequential periodate-chlorite oxidation.

    Science.gov (United States)

    Liimatainen, Henrikki; Visanko, Miikka; Sirviö, Juho Antti; Hormi, Osmo E O; Niinimaki, Jouko

    2012-05-14

    Sequential regioselective periodate-chlorite oxidation was employed as a new and efficient pretreatment to enhance the nanofibrillation of hardwood cellulose pulp through homogenization. The oxidized celluloses with carboxyl contents ranging from 0.38 to 1.75 mmol/g could nanofibrillate to highly viscous and transparent gels with yields of 100-85% without clogging the homogenizer (one to four passes). On the basis of field-emission scanning electron microscopy images, the nanofibrils obtained were of typical widths of approximately 25 ± 6 nm. All of the nanofibrillar samples maintained their cellulose I crystalline structure according to wide-angle X-ray diffraction results, and the crystallinity index was approximately 40% for all samples. PMID:22512713

  6. Fe-SAPONITE and Chlorite Growth on Stainless Steel in Hydrothermal Engineered Barrier Experiments

    Science.gov (United States)

    Cheshire, M. C.; Caporuscio, F. A.; McCarney, M.

    2012-12-01

    The United States recently has initiated the Used Fuel Disposition campaign to evaluate various generic geological repositories for the disposal of high-level, spent nuclear fuel within environments ranging from hard-rock, salt/clay, to deep borehole settings. Previous work describing Engineered Barrier Systems (EBS) for repositories focused on low temperature and pressure conditions. The focus of this experimental work is to characterize the stability and alteration of a bentonite-based EBS with different waste container materials in brine at higher heat loads and pressures. All experiments were run at ~150 bar and 125 to 300 C for ~1 month. Unprocessed bentonite from Colony, Wyoming was used in the experiments as the clay buffer material. The redox conditions for each system were buffered along the magnetite-iron oxygen fugacity univariant curve using Fe3O4 and Feo filings. A K-Na-Ca-Cl-based salt solution was chosen to replicate deep groundwater compositions. The experimental mixtures were 1) salt solution-clay; 2) salt solution -clay-304 stainless steel; and 3) salt solution -clay-316 stainless steel with a water/bentonite ratio of ~9. Mineralogy and aqueous geochemistry of each experiment was evaluated to monitor the reactions that took place. No smectite illitization was observed in these reactions. However, it appears that K-smectite was produced, possibly providing a precursor to illitization. It is unclear whether reaction times were sufficient for bentonite illitization at 212 and 300 C or whether conditions conducive to illite formation were obtained. The more notable clay mineral reactions occurred at the stainless steel surfaces. Authigenic chlorite and Fe-saponite grew with their basal planes near perpendicular to the steel plate, forming a 10 - 40 μm thick 'corrosion' layer. Partial dissolution of the steel plates was the likely iron source for chlorite/saponite formation; however, dissolution of the Feo/Fe3O4 may also have acted as an iron source

  7. Scales of equilibrium and disequilibrium during cleavage formation in chlorite and biotite-grade phyllites, SE Vermont

    Science.gov (United States)

    McWilliams, C.K.; Wintsch, R.P.; Kunk, M.J.

    2007-01-01

    Detailed electron microprobe analyses of phyllosilicates in crenulated phyllites from south-eastern Vermont show that grain-scale zoning is common, and sympathetic zoning in adjacent minerals is nearly universal. We interpret this to reflect a pressure-solution mechanism for cleavage development, where precipitation from a very small fluid reservoir fractionated that fluid. Multiple analyses along single muscovite, biotite and chlorite grains (30-200 ??m in length) show zoning patterns indicating Tschermakitic substitutions in muscovite and both Tschermakitic and di/trioctahedral substitutions in biotite and chlorite. Using cross-cutting relationships and mineral chemistry it is shown that these patterns persist in cleavages produced at metamorphic conditions of chlorite-grade, chlorite-grade overprinted by biotite-grade and biotite-grade. Zoning patterns are comparable in all three settings, requiring a similar cleavage-forming mechanism independent of metamorphic grade. Moreover, the use of 40Ar/ 39Ar geochronology demonstrates this is true regardless of age. Furthermore, samples with chlorite-grade cleavages overprinted by biotite porphyroblasts suggest the closure temperatures for the diffusion of Al, Si, Mg and Fe ions are greater than the temperature of the biotite isograd (>???400 ??C). Parallel and smoothly fanning tie lines produced by coexisting muscovite-chlorite, and muscovite-biotite pairs on compositional diagrams demonstrate effectively instantaneous chemical equilibrium and probably indicate simultaneous crystallization. These results do not support theories suggesting cleavages form in fluid-dominated systems. If crenulation cleavages formed in systems in which the chemical potentials of all major components are fixed by an external reservoir, then the compositions of individual grains defining these cleavages would be uniform. On the contrary, the fine-scale chemical zoning observed probably reflects a grain-scale process consistent with a

  8. Elucidation of the mechanism of enzymatic browning inhibition by sodium chlorite.

    Science.gov (United States)

    He, Qiang; Luo, Yaguang; Chen, Pei

    2008-10-15

    Sodium chlorite (SC) is a well known anti-microbial agent and its strong inhibitory effect on enzymatic browning of fresh-cut produce has recently been identified. We investigated the effect of SC on polyphenol oxidase (PPO) and its substrate, chlorogenic acid (CA), as it relates to the mechanisms of browning inhibition by SC. Results indicate that the browning reaction of CA (1.0mM) catalyzed by PPO (33U/mL) was significantly inhibited by 1.0mM SC at pH 4.6. Two PPO isoforms were identified by native polyacrylamide gel electrophoresis, and both were inactivated by SC (3.0mM). This suggests that SC serves as a PPO inhibitor to prevent enzymatic browning. Furthermore, the effect of SC on the stability of CA in both acidic (pH 4.5) and basic conditions (pH 8.3) was studied by UV-Vis scan and LC-MS analysis. The results showed that at the presence of SC (3.0mM), CA (0.1mM) degraded to quinic acid and caffeic acid as well as other intermediates. Hence, the anti-browning property of SC can be attributed to the two modes of action: the inactivation of polyphenol oxidase directly and the oxidative degradation of phenolic substrates.

  9. Removal of Hg~0 with sodium chlorite solution and mass transfer reaction kinetics

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The absorption behavior of Hg0 was studied experimentally by using sodium chlorite solution(NaClO2) as the absorbent in a bubble reactor.Primary influencing factors on removal efficiency of Hg0 such as NaClO2 concentration,pH,reaction temperature and the concentration of Hg0 were investigated.The results indicated that 72.91% of Hg0 removal efficiency could be achieved in acidic NaClO2 solution.The removal mechanism of Hg0 was proposed by analyzing of Hg2+ concentration in ab-sorption solution after reaction and comparing the electrode potentials between NaClO2 species and Hg2+/Hg0.The experimental results of mass transfer-reaction kinetics on oxidation of Hg0 by NaClO2 solution showed that with the increase of NaClO2 concentration and the decrease of pH value,the enhancement factor(E) and ratio of KG(Hg0)/kG(Hg0) increased and the liquid phase mass transfer resistance decreased,which is benefit to the mass transfer adsorption reaction.Although the increase of reaction temperature could improve the enhancement factor(E),but the ratio of KG(Hg0)/kG(Hg0) decreased;as a result,the liquid phase mass transfer resistance increased,therefore,the reaction rate for removal of Hg0 decreased.

  10. Ordinary Toxicity of Chlorine Dioxide and By-products Chlorite and Chlorate in Water

    Institute of Scientific and Technical Information of China (English)

    王丽; 常爱敏; 黄君礼

    2003-01-01

    Acute toxicity and accumulated toxicity of chlorine dioxide (C1O2) and by-products chlorite ( C1O-2 ) and chlorate (C1O-3) in water acted on mice are studied by the method of Horn and accumulation coefficient.Subchronic toxicity of the mixture of C1O2 and C1O-2 and ClO-3 in water acted on rat is studied though feeding test for 90 days, including statistical analysis of variance on weight gaining, food utilization efficiency, index of blood and serum, liver (or kidney)to body weight ratio, and histopathological examination on liver and kidney. The results show that aqueous solution of C1O2, NaC1O2 and NaC1O3 (with the concentration of 276. 5 mg/L, 200 mg/L and 200 mg/L respectively) and the mixed aqueous solution of C1O2 with the concentration of 553 mg/L are actually non poisonous, and non-cumulative aqueous solution as well.

  11. Paragenesis of Cr-rich muscovite and chlorite in green-mica quartzites of Saigaon–Palasgaon area, Western Bastar Craton, India

    Indian Academy of Sciences (India)

    K R Randive; M M Korakoppa; S V Muley; A M Varade; H W Khandare; S G Lanjewar; R R Tiwari; K K Aradhi

    2015-02-01

    Green mica (fuchsite or chromian-muscovite) is reported worldwide in the Archaean metasedimentary rocks, especially quartzites. They are generally associated with a suite of heavy minerals and a range of phyllosilicates. We report the occurrence of green-mica quartzites in the Saigaon–Palasgaon area within Bastar Craton in central India. Mineralogical study has shown that there are two types of muscovites; the chromium-containing muscovite (Cr2O3 0.84–1.84%) and muscovite (Cr2O3 0.00–0.22%). Chlorites are chromium-containing chlorites (Cr2O3 3.66–5.39%) and low-chromium-containing chlorites (Cr2O3 0.56–2.62%), and as such represent ripidolite–brunsvigite varieties. Back scattered electron images and EPMA data has revealed that chlorite occurs in two forms, viz., parallel to subparallel stacks in the form of intergrowth with muscovite and independent crystals within the matrix. The present study indicates that the replacement of chromium-containing chlorite by chromium-containing muscovite is found to be due to increasing grade of metamorphism of chromium-rich sediments. However, the absence of significant compositional gap between aforementioned varieties indicates disparate substitution of cations, especially chromium, within matrix chlorites. The chromium-containing muscovite and muscovite are two separate varieties having distinct paragenesis.

  12. Effectiveness of acidified sodium chlorite and other sanitizers to control Escherichia coli O157:H7 on tomato surfaces.

    Science.gov (United States)

    Inatsu, Yasuhiro; Kitagawa, Tomoko; Bari, Md Latiful; Nei, Daisuke; Juneja, Vijay; Kawamoto, Shinichi

    2010-06-01

    The use of a suitable sanitizer can reduce the risk of produce-related foodborne illnesses. We evaluated the effectiveness of several sanitizers to reduce inoculated Escherichia coli O157:H7 on the surface of cherry tomatoes (Solanum lycopersicum var. cerasiform). Depending on the method of inoculation (dipping/spotting), each of 80 g (eight tomatoes) of inoculated cherry tomatoes was washed in 400 mL of sanitizer solutions or 400 mL distilled water for 5 minutes. The effectiveness of sanitizers on spot-inoculated E. coli O157:H7 on tomato surfaces was found higher than on dip-inoculated tomatoes. Washing with water or chlorine water (0.1 g/L as free chlorine) could reduce 1.3 log CFU/g of E. coli O157:H7 in dip-inoculated (6.8 log CFU/g) tomatoes. Washing with lactic acid (LA) solution (1.0 g/L), phytic acid solution (1.0 g/L), calcinated seashells (oyster/sakhalin surf clam), and 1.0 g/L chitosan in 0.5 g/L LA (Chito) did not exhibit a significant higher effectiveness than that of water wash alone (1.0 log CFU/g). Acidified sodium chlorite (ASC) solution prepared from 0.5 g/L of sodium chlorite and 1.0 g/L LA or phytic acid reduced 3.5 log CFU/g of E. coli O157:H7 in dip-inoculated tomato surfaces. ASC (0.5 g/L of sodium chlorite and 1.0 g/L of LA) wash followed by a second wash with LA exhibited an additional sanitary effectiveness compared to a single wash with ASC. However, washing with ASC followed by a second wash with Chito exhibited an additional 1.0 log CFU/g reduction compared to a secondary wash with water. No significant difference of color, taste, and texture was observed among the washed cherry tomatoes. PMID:20113205

  13. Comparison of the effects of chlorite-oxidized oxyamylose and polyacrylic acid on the multiplication of phytopathogenic viruses.

    Science.gov (United States)

    Kluge, S

    1985-10-01

    Polyacrylic acid (PAA) and chlorite-oxidized oxyamylose (COAM) inhibit the multiplication of tobacco mosaic virus (TMV) in leaf disks by up to 50%. The reduction in TMV content is time-dependent and decreases with longer time intervals between the virus infection and the application of substances. The multiplication of potato virus X (PVX) in leaf disks is not affected by either PAA or COAM. In intact plants PAA produces a strong antiviral effect on both PVX and red clover mottle virus (RCMV). The effect produced by COAM is much less pronounced, although this substance is less toxic and could be used in a higher concentration than PAA. Neither of these compounds has a significant influence on the development of virus-induced necroses in Nicotiana glutinosa, Gomphrena globosa or Phaseolus vulgaris plants when administered one day before or after virus infection.

  14. Multiple hydrothermal and metamorphic events in the Kidd Creek volcanogenic massive sulphide deposit, Timmins, Ontario: evidence from tourmalines and chlorites

    Science.gov (United States)

    Slack, J.F.; Coad, P.R.

    1989-01-01

    The tourmalines and chlorites record a series of multiple hydrothermal and metamorphic events. Paragenetic studies suggest that tourmaline was deposited during several discrete stages of mineralization, as evidence by brecciation and cross-cutting relationships. Most of the tourmalines have two concentric growth zones defined by different colours (green, brown, blue, yellow). Some tourmalines also display pale discordant rims that cross-cut and embay the inner growth zones and polycrystalline, multiple-extinction domains. Late sulphide veinlets (chalcopyrite, pyrrhotite) transect the inner growth zones and pale discordant rims of many crystals. The concentric growth zones are interpreted as primary features developed by the main ore-forming hydrothermal system, whereas the discordant rims, polycrystalline domains, and cross-cutting sulphide veinlets reflect post-ore metamorphic processes. Variations in mineral proportions and mineral chemistry within the deposit mainly depend on fluctuations in temperature, pH, water/rock ratios, and amounts of entrained seawater. -from Authors

  15. Assessment of sodium hypochlorite and acidified sodium chlorite as antimicrobial agents to inhibit growth of Escherichia coli O157:H7 and natural microflora on shredded carrots

    Science.gov (United States)

    The influence of cold tap water, sodium hypochlorite (200 ppm) and acidified sodium chlorite (100, 250, 500 and 1000 ppm) washes on survival and growth of Escherichia coli O157:H7 inoculated onto shredded carrots was determined after treatment and 7 and 14 days of storage. Growth of total mesophilic...

  16. A case of severe chlorite poisoning successfully treated with early administration of methylene blue, renal replacement therapy, and red blood cell transfusion : case report

    NARCIS (Netherlands)

    Gebhardtova, Andrea; Vavrinec, Peter; Vavrincova-Yaghi, Diana; Seelen, Mark; Dobisova, Anna; Flassikova, Zora; Cikova, Andrea; Henning, Robert H.; Yaghi, Aktham

    2014-01-01

    The case of a 55-year-old man who attempted suicide by ingesting <100 mL of 28% sodium chlorite solution is presented. On arrival in the intensive care unit, the patient appeared cyanotic with lowered consciousness and displayed anuria and chocolate brown serum.Initial laboratory tests revealed 40%

  17. Efficacy of sodium hypochlorite and acidified sodium chlorite in preventing browning and microbial growth on fresh-cut produce.

    Science.gov (United States)

    Sun, Shih Hui; Kim, Su Jin; Kwak, Soo Jin; Yoon, Ki Sun

    2012-09-01

    The use of suitable sanitizers can increase the quality of fresh-cut produce and reduce the risk of foodborne illnesses. The objective of this study was to compare the washing effects of 100 mg/L sodium hypochlorite (SH) and 500 mg/L acidified sodium chlorite (ASC) on the prevention of enzymatic browning and the growth of microbial populations, including aerobic plate counts, E. coli, and coliforms, throughout storage at 4°C and 10°C. Fresh-cut zucchini, cucumbers, green bell peppers, and root vegetables such as potatoes, sweet potatoes, carrots, and radishes were used. Compared to SH washing, ASC washing significantly (pfresh-cut produce and prevented browning of fresh-cut potatoes and sweet potatoes during storage. More effective inhibition of aerobic plate counts and coliforms growth was observed on fresh-cut produce treated with ASC during storage at 10°C. Polyphenol oxidase (PPO) activity of fresh-cut potatoes and sweet potatoes was more effectively inhibited after washing with ASC. The use of 500 mg/L ASC can provide effective antimicrobial and anti-browning treatments of fresh-cut produce, including processed root vegetables.

  18. Coupled Petrological and Geodynamic Models of Mantle Flow in Subduction Zones; the Importance of Chlorite in the Emergence of a Low-Viscosity Channel

    Science.gov (United States)

    Smith, P. M.; Baker, L. J.; Asimow, P. D.; Gurnis, M. C.

    2007-12-01

    Seismic velocity and attenuation studies have shown that 5-20 km thick low velocity layers exist above seismically fast slabs and are associated with broad zones of high attenuation in many subduction zones. These observations are generally interpreted as formation of hydrous phases by dehydration of the slab, although the impact of water in nominally anhydrous minerals (NAM) on seismic wave propagation is largely unknown. Recent petrological experiments on hydrous peridotite at subduction zone conditions suggest that chlorite will be stable adjacent to the subducting slab in sufficient quantities to be a significant water sink. We use a scheme that couples a petrological model (pHMELTS) with a 2-D thermal and variable viscosity flow model (ConMan) to model energy and mass transfer within a subduction zone. By varying input parameters including the convergence rate and slab dip we have developed models for cases in the Costa-Rica and Izu- Bonin-Marianas arc systems and are able to predict major and trace element compositions of primary melts, as well as geophysical observables, such as the topography and geoid. We find that the emergence of a slab- adjacent low-viscosity channel (LVC) is a natural consequence of the thermal and chemical controls on mantle dynamics and feedback between them. In our earlier models, as the LVC is dragged downwards by the subducting slab, hornblende breaks down at about 2.5 GPa and other hydrous phases such as serpentine are secondary in importance to the NAM water reservoir. The spatial limit of the LVC is the water-saturated solidus of the hydrated peridotite; the LVC thickens as the peridotite is progressively depleted by melting and the solidus migrates into the warmer wedge, despite water replenishment at depth. pHMELTS is a hybrid of the pMELTS model of Ghiorso and co-workers and includes amphiboles, serpentines and micas. Chlorite was lacking but we have recently rectified this omission. Following De Capitani and co- workers, we

  19. Ultramafic-hosted Hydrothermal Systems at Mid-Ocean Ridges: Serpentinization, Chloritization and Geochemical Controls on Mass-Transfer Processes

    Science.gov (United States)

    Seyfried, W. E.; Pester, N. J.; Ding, K.

    2012-12-01

    concentrations and calculated subseafloor pH and temperature. The Rainbow hydrothermal system is also associated with a dome-like massif and morphology typical of Ocean Core Complexes. In sharp contrast with the LCHF, however, the Rainbow hydrothermal system is characterized by vent fluid temperatures in excess of 365°C, high dissolved Fe, Cu and Zn, and low pH (pH25°C=3.25). In-situ pH for Rainbow vent fluid (369°C) was determined to be 5.0±0.03. Trace alkali element concentrations indicate relatively low fluid/rock ratios, while dissolved B concentrations are depleted relative to seawater, but to a lesser degree than measured for Lost City vent fluid. Moderate concentrations of dissolved silica suggest fluid chemistry buffered by chlorite-fluid equilibria. Fluid flow in close proximity to gabbroic intrusions likely drives hydrothermal convection and mass transfer, although it is still unclear whether gabbroic intrusions alone can account for the enormous heat flux and the long duration of continuous hydrothermal activity observed for the Rainbow hydrothermal system.

  20. Efficacy of two acidified chlorite postmilking teat disinfectants with sodium dodecylbenzene sulfonic acid on prevention of contagious mastitis using an experimental challenge protocol.

    Science.gov (United States)

    Oura, L Y; Fox, L K; Warf, C C; Kempt, G K

    2002-01-01

    Two acidified sodium chlorite postmilking teat disinfectants were evaluated for efficacy against Staphylococcus aureus and Streptococcus agalactiae by using National Mastitis Council experimental challenge procedures. The effect of these teat dips on teat skin and teat end condition was also determined. Both dips contained 0.32% sodium chlorite, 1.32% lactic, and 2.5% glycerin. Dips differed in the amount of sodium dodecylbenzene sulfonic acid (0.53 or 0.27%) added as a surfactant. Both dips significantly reduced new intramammary infection (IMI) rates compared with undipped controls. The dip containing 0.53% dodecylbenzene sulfonic acid reduced new IMI by Staph. aureus by 72% and Strep. agalactiae by 75%. The dip containing 0.27% dodecylbenzene sulfonic acid reduced new IMI by Staph. aureus by 100% and by Strep. agalactiae by 88%. Changes in teat skin and teat end condition for treatment and control groups varied in parallel over time. Teats treated with either teat dip had higher mean teat skin and teat end scores than control teats at some weeks. However, teat skin and teat end condition did not tend to change from the start to the completion of the trial. Application of the two new postmilking teat dips was effective in reducing new IMI from contagious mastitis pathogens. (Key words: teat dip, contagious mastitis, chlorous acid) PMID:11860118

  1. Character of Chlorite and Its Relationship to Uranium Mineralization in Uranium Deposit No.302%302铀矿床绿泥石特征及其与铀成矿的关系

    Institute of Scientific and Technical Information of China (English)

    郭国林; 刘晓东; 潘家永; 张展适; 李兴斌

    2012-01-01

    Based on the EPMA analysis and mineralogy study, the chlorites in uranium deposit No. 302 are classified into 4 types which have 4 occurrences respectively. The forming condition and tempretures of chlorites were discussed and used to deduce the forming condition of uranium forming environment. The forming process of uranium mineralization was believed to experience different tempreture at different stage. In pro-mineralization stage, the hydrothermal solution was of high tempreture and first resulted in the chlorization of biotite, and then the metasomatism of feldspar to form chlorite of feldspar alteration type and fissure filling type. In mineralization stage, the hydrothermal solution was of low tempreture and form disseminated chlorite.%通过对302铀矿床的蚀变矿物绿泥石进行电子探针成分分析和矿物学研究,提出该矿床的绿泥石分属4种成因类型,具有4种产出形态;探讨了绿泥石的形成环境和温度,并以此对铀成矿环境进行推断.302铀矿床的成矿过程可表述为矿前期在相对较高温度的热液流体作用下,黑云母发生绿泥石化蚀变,随后热液继续交代长石,形成长石蚀变型、裂隙充填型绿泥石,进而在成矿期热液温度相对较低的条件下形成浸染型绿泥石.

  2. Study on abatement of chlorite in drinking water pipe network in north city%北方某城市饮用水管网中亚氯酸盐调查

    Institute of Scientific and Technical Information of China (English)

    李妍; 崔崇威; 许铁夫

    2014-01-01

    为保证饮用水给水管网的水质安全,通过现场实验对以二氧化氯为惟一消毒剂的典型管网进行连续试验检测,获得实际管网的二氧化氯消毒副产物亚氯酸盐和氯酸盐的变化规律并对其影响因素进行分析.结果表明,氯酸盐在实际管网中的量均小于0.05 mg/L,而亚氯酸盐在连接管、转弯管和支管的质量浓度分布明显偏低,说明实际管网中的管垢和流速是影响亚氯酸盐质量浓度变化的关键因素.实际管网内二氧化氯消毒副产物的调查分析对消毒剂的安全使用以及饮用水品质的提高具有重要意义.%This paper was designed to study the concentration of chlorite and elucidate the factors on concentration of chlorite in drinking water pipe network disinfected by chlorine di -oxide.The result showed that the lowest concentration of chlorite was connecting tube , elbow tube and branch in drinking water pipe network .The most important impact on chlorite was pipe sordes and flow rate .The transformation of chlorine dioxide disinfection byproducts in pipe network considered drinking water from safe to health play an important role .

  3. Simultaneous determination of bromate, chlorite and haloacetic acids by two-dimensional matrix elimination ion chromatography with coupled conventional and capillary columns.

    Science.gov (United States)

    Teh, Hui Boon; Li, Sam Fong Yau

    2015-02-27

    A new, highly sensitive and reliable two-dimensional matrix elimination ion chromatography (IC) method was developed for simultaneous detection of bromate, chlorite and five haloacetic acids. This method combined the conventional IC in first dimension with capillary IC in the second dimension coupled with suppressed conductivity detection. The first dimension utilizes a high capacity column to partially resolve matrix from target analytes. By optimizing the cut window, the target analytes were selectively cut and trapped in a trap column through the use of a six-port valve, while the separated matrix were diverted to waste. The trapped target analytes were delivered on to the capillary column for further separation and detection. Temperature programming was used to improve selectivity in second dimension column to obtain complete resolution of the target analytes. Compared to the performance of one-dimensional IC, the two-dimensional approach resulted in a significant increase in sensitivity for all target analytes with limit of detection ranging from 0.30 to 0.64μg/L and provided more reliable analysis due to second column confirmation. Good linearity was obtained for all the target analytes with correlation coefficients >0.998. The proposed method was successfully applied to the determination of oxyhalides and haloacetic acids in various matrices with recoveries ranging from 90 to 116% and RSD less than 6.1%. The method allows direct injection of samples and the use of columns with different selectivity, thus significantly reduces the level of false positive results. The method is fully automated and simple, making it practical for routine monitoring of water quality. The satisfactory results also demonstrated that the two-dimensional matrix elimination method coupled with capillary IC is a promising approach for detection of trace substances in complex matrices.

  4. Ion chromatographic determination of trace iodate, chlorite, chlorate, bromide, bromate and nitrite in drinking water using suppressed conductivity detection and visible detection.

    Science.gov (United States)

    Binghui, Zhu; Zhixiong, Zhong; Jing, Yao

    2006-06-16

    An ion chromatography method for the simultaneous determination of trace iodate, chlorite, chlorate, bromide, bromate and nitrite in drinking water has been developed using an anion-exchange column and the suppressed conductivity detector, followed by post-column addition of reagent to enhance visible absorbance detection of ions. A high capacity anion exchange Ion Pac9-HC column (250 mm x 4 mm I.D.) was used. Eight millimole per liter sodium carbonate was used as eluent, an auto-suppression external water mode was selected, 0.5 g/l o-dianisidine.2HCl (ODA)+4.5 g/l KBr+25% methanel+5.6% nitric acid was used as post-column reagent. The post-column reaction (PCR) temperature was at 60 degrees C, and the visible absorbance detected wavelength at 450 nm. The sample's pH and coexist anions had no influence on determination. The method enjoyed a wide linear range and a good linear correlation coefficient (r>0.999). The method detection limits were between 0.023 and 2.0 microg/l. The average recoveries ranged from 87.5 to 110.0%, and the relative standard deviations (RSD) were in the range of 1.1-4.6%. The analytical results by the method of post-column addition of reagent to enhance visible absorbance detection of anions was compared with that of the suppressed conductivity detection, and the former was proved to be better in sensitivity and selectivity. The results showed that this method was accurate, sensitive and might be good for application and suitable for trace analysis at the level of mug/l.

  5. 法国比利牛斯山Trimouns滑石-绿泥石矿床地质与成因%Geology and ore genesis of the Trimouns talc-chlorite ore deposit,Pyrénées,France

    Institute of Scientific and Technical Information of China (English)

    Ph de PARSEVAL; 蒋少涌; F FONTAN; 王汝成; F MARTIN; J FREEET

    2004-01-01

    位于法国比利牛斯山的nimouns矿床是世界上最大的滑石-绿泥石矿床之一.对该矿床形成的条件及滑石和绿泥石矿石的含量已较清楚.它是由不同类型的岩石通过热液交代蚀变而形成的,主要包括白云岩蚀变为滑石为主的矿石和硅铝质岩石(云母片岩和伟晶岩)蚀变为绿泥石为主的矿石.滑石矿石显示片理化结构(滑石片岩)或压实块状结构(块滑石).由伟晶岩蚀变而来的绿泥石矿石为呈绿色的球状矿体,而由云母片岩蚀变而来的绿泥石矿石呈块状或片理状、颜色为灰绿色和深灰色.本文对欧洲这个独一无二的滑石和绿泥石矿床的地质特征和成因进行了总结和讨论.流体包裹体研究表明成矿流体为高盐度(20 to30%eq.wt%NaCl)、中温(320℃)、压为为2.5kbars.磷钇矿和独居石的U-Pb定年结果表明,成矿年代为112~97Ma,成矿作用可能持续了16Ma以上.%The Trimouns deposit, in the French Pyr閚閑s, is one of the largest talc and chlorite exploitation in the world. The conditions of formation and concentration for talc and chlorite ores are now well known. The deposit consists the metasomatic alteration of various rocks, mainly dolostones altered into talc-dominant ore and silico-aluminous rocks (mica schists and pegmatites) into chlorite-dominant ore. The talc ore shows schisteous texture (talc schist) or in compact mass (steatite). The chlorite ore altered from pegmatite show green colors and ball bodies. The chlorite ores altered from mica schists are either massive or schisteous ores with graygreenish and dark gray colors. This paper summarizes the general geology and ore genesis of this exceptional talc and chlorite ore deposit in Europe. Fluid inclusion study shows high salinity of 20 to 30% eq. wt% NaCl, intermediate temperature of 320℃ and pressure of 2.5 kbars for the formation of Trimouns deposit. According to U-Pb dating on xenotime and monazite, the mineralization took

  6. Characterization of Zn-bearing chlorite by Moessbauer and infrared spectroscopy - occurrence associated to the Pb-Zn-Ag deposits of Canoas, PR, Brazil; Caracterizacao de clorita portadora de Zn por espectroscopia Moessbauer e espectroscopia infravermelho - uma ocorrencia associada ao deposito de Pb-Zn-Ag de Canoas, PR, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Imbernon, Rosely Aparecida Liguori [Universidade de Sao Paulo (EACH/USP), SP (Brazil). Escola de Artes, Ciencias e Humanidades; Blot, Alain [Institut de Recherche pour le Developpement (IRD), Paris (France); Pereira, Vitor Paulo [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Geociencias; Franco, Daniel Ribeiro, E-mail: imbernon@usp.br, E-mail: brotalain@free.fr, E-mail: vitor.pereira@ufrgs.br, E-mail: drfranco@on.br [Observatorio Nacional do Brasil (COGE/ON), Rio de Janeiro, RJ (Brazil). Coordenacao de Geofisica

    2011-06-15

    In order to provide new insights on mineralogical aspects of geochemical mapping/natural processes related to the chlorite formation (e.g. crystallochemistry and mechanisms of formation of these materials, which has been applied in different studies of environmental profiles), we investigated chlorite samples associated to the Pb-Zn-Ag sulfide ore from Canoas 1 deposit (Vale do Ribeira, state of Parana, Brazil). By means of Moessbauer (MS) and infrared (IV) spectroscopy, we addressed some issues as those related to the chloritization processes, as well as how Zn would be incorporated into its crystalline structure. Results carried out by ME and IV spectroscopy clearly pointed out for a chlorite occurrence, which in fact incorporates Zn into its structure and also alters the structural patterns for this mineral. Moreover, ME data sets indicated the presence of Fe which is located only in octahedral sites, in trans-configuration, and the Zn emplacement by the chloritization process also occurs in the brucite layer. (author)

  7. 二氧化氯消毒饮用水中亚氯酸盐污染的初步研究%Priliminary Study on Chlorite Pollution of Drinking Water Disinfected by Chlorine Dioxide

    Institute of Scientific and Technical Information of China (English)

    施小平; 周明浩

    2000-01-01

    [Objective] To explore the status of chlorite pollution in drinking water due to chlorine dioxide , aswell as its causes and counter measures. [Methods]A water plant collecting surface water as raw water slightly pol-luted by organic compounds and B water plant collecting ground water without organic compounds pollution wereselected as observed objectives. Chlorine dioxide generators were used in both of A and B water plants, their rawmaterials was chlorite for A plant and chlorate for B plant. The levels of chlorite in treated water from these twowater plants were determined by amperometric titration. [Results]The levels of chlorite in treated water of A waterplant ranged 0.530~0.760 mg/L, 2.6~3.8 times of the standard value, with a over standard rate of 100%, thelevels of B water plant range 0.257~0.733 mg/L, 1.3~3.7 times of the standard value, with a over standard rateof 83.3%. [Conclusion] The treated water of A and B water plants presented higher pollution by chlorite, the by-product of chlorine dioxide disinfection.%[目的]了解二氧化氯消毒饮用水产生的亚氯酸盐(ClO2-)污染现状,并探讨其成因和对策。[方法]选择2个自来水厂,其中甲水厂以受轻度有机物污染的地面水为水源,乙水厂以未受有机物污染的地下水为水源,两个水厂均使用二氧化氯发生器,主要原料甲厂为亚氯酸盐,乙厂为氯酸盐。采用电流滴定仪法测定这2个水厂出厂水中ClO2-浓度。[结果]出厂水ClO2-浓度:甲厂0.530~0.760 mg/L,为标准值的2.6~3.8倍,超标率100%;乙厂0.100~0.733 mg/L,其中超标浓度值范围0.257~0.733 mg/L,为标准值的1.3~3.7倍,超标率83.3%。[结论]甲、乙自来水厂出厂水中由二氧化氯消毒产生的消毒副产物亚氯酸盐污染较严重。

  8. 饮用水中的亚氯酸盐、氯酸盐和溴酸盐的离子色谱测定法%Determination of Chlorite ,Chlorate and Bromate in Drinking Water by Ion Chromatography

    Institute of Scientific and Technical Information of China (English)

    周虹; 周小新

    2009-01-01

    Objective To develop an ion chromatography (IC) for simultaneous determination of chlorite, chlorate and bromate in drinking water. Methods The IC separation was carried out with the IonPAC AS23 column by using 4.5 mmol/L Na_2CO_3-0.8 mmol/L NaHCO_3 at the flow rate of 1.0 ml/min. The injection volume was 250 μl.the temperature of conductivity detector cell and column were 30 ℃ and 35 ℃, respectively. The pressure upon the bottle of mobile phase was 40 kPa. The current of auto-regenerating suppressor was 25 mA. Results The results showed that in the range of 0 to 1 000 mg/L, the calibration equation for chlorite was y=0.009 6+1.600 0 x (r=0.999 3),for bromate was y=0.003 2+3.184 7 x (r=0.999 9),for chlorate was y= 0.001 8+1.788 9 x(r=0.999 9).The detection limit of chlorite,chlorate and bromate were all 5 μg/ L,the recovery rates were 89.0% -108.0% and the relative standard deviations (RSD) were 0.21%-2.70%. Conclusion The method is simple,fast,accurate, sensitive, little interference and is applicable to the simultaneous determination of chlorite, chlorate and bromate in drinking water.%目的 建立同时测定饮用水中亚氯酸盐、氯酸盐和溴酸盐的离子色谱法.方法 选择IonPacAS23色谱柱,淋洗液为4.5mmol/L Na_2CO_3-0.8 mmol/L NaHCO_3,流速为1.0 ml/min,进样量为250 μl,电导检测池温度为30℃,色谱柱温度为35 ℃,流动相瓶加压为40 kPa,抑制器抑制模式为自动再生模式,抑制器电流为25 mA.结果 在0~1 000.0 mg/L范围内,亚氯酸盐的线性方程为:y=0.009 6+1.600 0x,r=0.999 3,检出限为5μg/L;溴酸盐的线性方程为:y=0.003 2+3.184 7x,r=0.999 9,检出限为5μg/L;氯酸盐的线性方程为:y=0.001 8+1.788 9x,r=0.999 9,检出限为5μg/L.加标回收试验结果显示,该方法的平均回收率为89.0%~108.0%,RSD为0.21%~2.70%.结论 该法操作简单、快速、准确,灵敏度高、干扰少,适用于饮用水中亚氯酸盐、氯酸盐和溴酸盐的同时测定.

  9. Production and stability of chlorine dioxide in organic acid solutions as affected by pH, type of acid, and concentration of sodium chlorite, and its effectiveness in inactivating Bacillus cereus spores.

    Science.gov (United States)

    Kim, Hoikyung; Kang, Youngjee; Beuchat, Larry R; Ryu, Jee-Hoon

    2008-12-01

    We studied the production and stability of chlorine dioxide (ClO(2)) in organic acid solutions and its effectiveness in killing Bacillus cereus spores. Sodium chlorite (5000, 10,000, or 50,000 microg/ml) was added to 5% acetic, citric, or lactic acid solution, adjusted to pH 3.0, 4.0, 5.0, or 6.0, and held at 21 degrees C for up to 14 days. The amount of ClO(2) produced was higher as the concentration of sodium chlorite was increased and as the pH of the acid solutions was decreased. However, the stability in production of ClO(2) was enhanced by increasing the pH of the organic acid solutions. To evaluate the lethal activity of ClO(2) produced in various acid solutions as affected by acidulant and pH, suspensions of B. cereus spores were treated at 21 degrees C for 1, 3, 5, or 10 min in hydrochloric acid or organic acid solutions (pH 3.0, 4.0, 5.0, or 6.0) containing ClO(2) at concentrations of 100, 50, or 25 microg/ml. Populations of viable spores treated with ClO(2) at concentrations of 100 or 50 microg/ml in organic acid solutions decreased more rapidly than populations treated with the same concentrations of ClO(2) in HCl. Rates of inactivation tended to increase with higher pH of ClO(2) solutions. Results show that ClO(2) formed in organic acid solutions has higher stability and is more lethal to B. cereus spores than ClO(2) formed at the same concentration in HCl solution. This finding emphasizes the benefits of using organic acid solutions to prepare ClO(2) intended for use as an antimicrobial.

  10. 生活饮用水中溴酸盐、氯酸盐和亚氯酸盐的离子色谱测定法%Determination of bromate, chlorate, and chlorite in drinking water by ion chromatography

    Institute of Scientific and Technical Information of China (English)

    孙卫明; 孙建飞; 王权帅

    2013-01-01

    [ Objective ] To establish a method for determination of bromate, chlorate, and chlorite in drinking water by ion chroma-tography. [ Methods] ] After filtration by 0.22 μm membrane filter, The water samples were put into the ion exchange system of ion chromatography, with the potassium hydroxide eluent. Different ions separated with the different affinity in one separation column and determined quantitatively by the external standard method. [ Results] Recoveries of bromate were 87.5% to 116.0% , and the relative standard deviation (RSD) was 69% ; recoveries of chlorate were 86. 8% to 99.0% , with RSD of 1. 21% ; recoveries of chlorite of 80.1% to 87.0% , with the RSD of 0.93% and the correlation coefficients of all 3 ions were r >0.999 0. [ Conclusion] This method is simple, rapid, can obtain satisfactory separation, with high sensitivity and precision. Also, the recovery meets the methodological requirements. Above all, this method is entirely suitable for the simultaneous determination of bromate, chlorate, and chlorite in drinking water.%目的 建立离子色谱法测定生活饮用水中有溴酸盐、氯酸盐、亚氯酸盐的检测方法.方法 水样经0.22 μm滤膜过滤后,随氢氧化钾淋洗液进入离子色谱的离子交换系统.根据分离柱对不同离子的亲和力不同进行分离,外标法定量.结果 溴酸盐回收率为87.5% ~ 116.0%,相对标准偏差为2.69%;氯酸盐回收率为86.8%~ 99.0%,相对标准偏差为1.21%;亚氯酸盐回收率为80.1% ~ 87.0%,相对标准偏差为0.93%.以上3个项目相关系数均大于0.999 0.结论 该方法检测速度快,样品处理简便,能获得满意的分离效果,具有较高的灵敏度和精密度,回收率也满足方法学要求,完全适合于生活饮用水中有溴酸盐、氯酸盐、亚氯酸盐的同时测定.

  11. Clinical analysis of vitamin B(6): determination of pyridoxal 5'-phosphate and 4-pyridoxic acid in human serum by reversed-phase high-performance liquid chromatography with chlorite postcolumn derivatization.

    Science.gov (United States)

    Rybak, Michael E; Pfeiffer, Christine M

    2004-10-15

    A reversed-phase high-performance liquid chromatography (HPLC) method with fluorometric detection was developed for the routine determination of pyridoxal 5'-phosphate (PLP) and 4-pyridoxic acid (4-PA) in serum. Chlorite postcolumn derivatization was used to oxidize PLP to a more fluorescent carboxylic acid form. Sensitivity improved fourfold for PLP using chlorite postcolumn derivatization over traditional bisulfite postcolumn derivatization. The HPLC injection cycle was 15 min, facilitating a throughput of 60 patient samples (72 injections that included standards and quality control (QC) samples) in 18.5h. Method precision was evaluated using three serum QC pools with PLP and 4-PA concentrations of 11.5-34.8 nmol/L and 10.4-21.0 nmol/L, respectively. Within-run (n=7) repeatabilities were 0.6-1.2% for PLP and 0.9-1.8% for 4-PA. Run-to-run (n=23) reproducibilities were 3.6-6.7% for PLP and 3.7-5.6% for 4-PA. Relative detection (3sigma(0)) and quantitation (10sigma(0)) limits were 0.3 and 0.9 nmol/L, respectively, for both PLP and 4-PA using a 10-microl sample injection volume. Analytical recoveries ranged from 97 to 102%. Patient-matched serum and plasma specimens (n=25) were analyzed to evaluate specimen-type bias. Of the plasma types evaluated, heparinized plasma introduced the lowest relative bias for PLP (-5.3%) and minimal bias for 4-PA (-2.3%) compared with serum. Ethylenediaminetetraacetic acid (EDTA) plasma showed the lowest bias for 4-PA (0.7%) but a relatively high bias for PLP (13.0%) due to a chromatographic interference. Human serum samples from a non-representative population subset (n=303) were commensurate with values published for other vitamin B(6) HPLC methods. These values gave geometric means of 42.4 nmol/L for PLP and 27.3 nmol/L for 4-PA. Medians for PLP and 4-PA were 40.1 and 21.8 nmol/L, respectively. The high sensitivity, precision, and throughput of this method, combined with its minimal serum specimen (150 microl) and sample injection

  12. An EPR study of native radiation-induced paramagnetic defects in sudoite (di-trioctahedral Al-Mg chlorite) from the alteration halo related to unconformity-type uranium deposits

    Science.gov (United States)

    Morichon, Élisa; Allard, Thierry; Beaufort, Daniel; Quirt, David

    2010-03-01

    Natural radiation-induced defects were identified in specimens of sudoite (Al-Mg di-trioctahedral chlorite) related to unconformity-type uranium deposits at the base of the Athabasca Group (Saskatchewan, Canada), using electron paramagnetic resonance (EPR) spectroscopy at X- and Q-band frequencies. X-band spectra indicate the presence of a main native defect, named the As-center, whose EPR signal is dominated by an axially distorted spectrum with apparent principal components as follows: g // = 2,051 and g ⊥ = 2,005, and a secondary defect with apparent component g = 2,025. The study of oriented specimens shows that the main defect has its g // component perpendicular to the ( ab) plane of sudoite. The As-center corresponds to an electron hole located on oxygen atoms of the structure and is likely associated with Si, according to the lack of hyperfine structure. The As-center in sudoite has EPR parameters similar to the A-center in kaolinite and dickite, and the Ai-center in illite. The saturation behavior of EPR spectra as a function of power demonstrates that native defects of sudoite are different from those known in other clays, such as kaolinite, dickite or smectite, but are similar to those of illite. The isochronal annealing data suggest that the main defect in sudoite is stable to more than 300°C. The corresponding defects characterized in sudoite may have the potential for tracing past radionuclide migration around unconformity-type uranium deposits.

  13. Determination of Chlorite, Bromate, Chlorate in Surface Water and Drinking Water by Ion Chromatography%离子色谱法测定地表水和饮用水中亚氯酸盐、溴酸盐和氯酸盐

    Institute of Scientific and Technical Information of China (English)

    窦艳艳; 杨丽莉; 徐荣; 胡恩宇

    2013-01-01

    采用KOH梯度淋洗离子色谱法测定地表水和饮用水中ClO2-、BrO3-和ClO3-,在试验确定的条件下,3种离子与F-、Cl-、NO2-、NO3-、SO2-4、Br-、I-等7种离子分离度良好。 ClO2-、BrO3-、ClO3-在50.0μg/L~1000μg/L范围内线性良好,检出限分别为5.2μg/L、8.9μg/L、7.6μg/L,环境水样加标平行测定的RSD分别为2.1%~5.4%、4.1%~5.4%、2.5%~4.8%,两个质量浓度水平加标的平均回收率分别为93.7%~96.5%、90.3%~94.8%、98.7%~111%。%An ion chromatography method for determining chlorite , bromate and chlorate in surface water and drinking water was studied .The separation of the anions was achieved on an IonPac AS 19 Column with KOH as eluent, the chlorite, bromate, chlorate and other 7 kinds of anions could be well separated and determined within 25 min by employing a concentration gradient .The method has good linearity during the concentration 50.0 μg/L ~1 000 μg/L.The method detection limits of chlorite, bromate and chlorate was 5.2 μg/L, 8.9 μg/L and 7.6 μg/L, respectively.The RSD of the samples were 2.1%~5.4% ( chlorite), 4.1%~5.4%(bromate), and 2.5%~4.8% (chlorate).The recoveries of chlorite, bromate and chlorate in water samples were 93.7%~96.5%, 90.3%~94.8%and 98.7%~111%.

  14. 亚氯酸钠对烤烟酶促棕色化反应及烟叶质量的影响%Effects of sodium chlorite on enzymatic browning reaction and curing quality of flue-cured tobacco

    Institute of Scientific and Technical Information of China (English)

    任杰; 李雨江; 包可翔; 赖成连; 冷平; 孙福山

    2012-01-01

    In order to study the effects of sodium chlorite(SC) on enzyme browning reaction and curing quality,the PPO activity,polyphenol content,chemical composition,smoking quality and economic characters of cured leaves of K326 were investigated.The results indicated that changes of PPO activity of tobacco leaves treated with SC and the control tobacco leaves were similar,but PPO activity of tobacco leaves treated with SC was lower than control tobacco leaves.The scopoletin and chlorogenic acid contents of middle leaves treated with SC were higher than the control leaves,but there was no significant difference of total polyphenol contents between SC treated and the control leaves.The chlorogenic acid,neochlorogenic acid,cryptochlorogenic acid,rutin and total polyphenol contents were higher than the control leaves.SC increased the chlorine and reducing sugar contents obviously,and made the chemical composition more coordinated.SC improved the smoking quality slightly,and increased the economic characters obviously.In conclusion,SC inhibited the enzymatic browning reaction and improved curing quality of flue-cured tobacco.%为研究亚氯酸钠(SC)对烤烟烘烤过程中酶促棕色化反应及烟叶烘烤质量的影响,以K326为试验材料,通过烘烤试验分析了SC对烤烟烘烤过程中多酚氧化酶(PPO)活性、烤后烟叶多酚含量、常规化学成分、感官质量及经济性状的影响。结果表明:SC处理和对照烟叶在烘烤过程中多酚氧化酶(PPO)活性变化表现出基本相同的规律,但SC处理烟叶PPO活性均低于同期对照烟叶。SC处理中部叶莨菪亭和绿原酸含量显著高于对照,但多酚总量与对照无显著差异;SC处理上部叶绿原酸、新绿原酸、隐绿原酸、芸香苷、多酚总量均显著高于对照。SC处理显著提高了烤后烟叶的氯含量和还原糖含量,使化学成分更趋协调。SC处理烤后烟叶感官质量较对照有所改善,经济性状较对照显

  15. Ion chromatography for simultaneous determination of bromate,chlorite and chlorate in drinking water%用离子色谱法同时测定生活饮水中溴酸盐、亚氯酸盐、氯酸盐

    Institute of Scientific and Technical Information of China (English)

    齐春华; 张颖; 王化勇

    2012-01-01

    Objective; To develop an ion chromatography (IC ) for simultaneous determination of chlorite, chlorate and bromate in drinking water. Methods: The IC separation was carried out with the IonPAC AS19 column by using hydroxide eluent at the flow rate of 1.0 ml/min. The injection volume was 500 jxl. Conductivity detection cell temperature was set at 30℃ , column temperature was set at 35℃. Suppressor was in automatic regeneration mode, suppressor current was 87 mA. Results: The results showed that in the range of 0 μg/L to 500 μg/L, the linear e-quation of chlorite was y =2. 640x -0.027, r =0.9999, the detection limit was 0. 1 μg/L; In the range of 0 μg/L ~ 100 μg/L, the linear equation of bromate was y = 1. 342x - 0. 003 , r - 0. 9999 , detection limit was 0. 5 μg/L; In the range of 0 μg/L -500 μg/L, the linear equation of chlorate was y =2. 157x -0. 043 , r -0. 9999, the detection limit was 0.2 μg/L. The recovery rates were 99. 70% ~102.6% and the relative standard deviations (RSD) were 1. 16% ~3.56%. Conclusion; The method is simple,fast,accurate, sensitive, little interference and applicable to the simultaneous determination of chlorite, chlorate and bromate in drinking water.%目的:建立能够同时测定生活饮用水中亚氯酸盐、氯酸盐和溴酸盐的离子色谱法.方法:选择Ion-PacAS19色谱柱,淋洗液为氢氧根淋洗液,流速为1.0 ml/min,进样量为500μl,电导检测池温度为30℃,色谱柱温度为35℃,抑制器抑制模式为自动再生模式,抑制器电流为87 mA.结果:在0μg/L ~ 500.0 μg/L范围内,亚氯酸盐的线性方程为:y=2.640x-0.027,r=0.9999,检出限为0.1 μg/L;在0μg/L ~ 100.0 μg/L溴酸盐的线性方程为:y=1.342x-0.003,r=0.9999,检出限为0.5 μg/L;在0μg/L~500.0 μg/L氯酸盐的线性方程为:y=2.157x-0.043,r=0.9999,检出限为0.2μg/L.加标回收试验结果显示,该方法的平均回收率为99.7% ~102.6%,RSD为1.16% ~3.56%.结论:该法操作简单、快速、准

  16. Simultaneous Determination of Trace Amount of Chlorite,Chlorate and Common Inorganic Anions in Running Water with kOH Isocratic Elution by Ion Chromatographic Method%KOH等度淋洗IC法同时测定自来水中微量ClO2-、ClO3-及常规阴离子

    Institute of Scientific and Technical Information of China (English)

    陈东; 罗倚坪

    2014-01-01

    The method to determine a trace of chlorite, chlorate and common inorganic anions in running water with KOH isocratic elution by ion chromatography was investigated. The conditions of method was that the concentration of KOH is 20. 5 mmol/L, the flow rate is 1. 0 mL/min, and the injection volume is 50 μL. The results showed that the concentration of F-,Cl-,NO3 -, SO4 2-,ClO2 -,ClO3 - in water was determined completely only in 12 minutes. The correlation coefficients of calibration curve was 0. 997 0-0. 999 9,while the detection limits was between 0. 05-7. 00 μg/L. The relative standard deviation( RSD) and the recoveries were between 0. 61%-3. 82%and 97. 6%-101. 7%, respectively. The method was sensitive, accurate and rapid, which was favorable to simultaneous quantification of chlorite, chlorate and common inorganic anions in drinking water.%建立了KOH等度淋洗离子色谱法同时测定自来水中微量亚氯酸盐、氯酸盐及氟化物、氯化物、硝酸盐、硫酸盐的分析方法。该方法以20.5 mmol/L KOH为淋洗液,流速1.0 mL/min,进样量50μL。结果表明,6种阴离子可在12分钟内检测完毕,各离子的线性相关系数为0.9970~0.9999;检出限为0.05~7.00μg/L;精密度为0.61%~3.82%;回收率为97.6%~101.7%,能够满足饮用水中这些指标的定量需要,是一种灵敏、准确、快速的理想方法。

  17. 21 CFR 173.325 - Acidified sodium chlorite solutions.

    Science.gov (United States)

    2010-04-01

    ... blanching, cooking, or canning. (f) The additive is used as an antimicrobial agent on processed, comminuted or formed meat food products (unless precluded by standards of identity in 9 CFR part 319) prior to....S.C. 552(a) and 1 CFR part 51. Copies are available from the Division of Petition Control...

  18. [Importance of Chlorite P in prevention and treatment in horticulture].

    Science.gov (United States)

    Szymański, J

    1993-01-01

    The Polish chlorine preparation for prophilaxis and controlling of bacterial blotch in the champignon culture and in order to carry out the general desinfection in champignon houses has been registered. This preparation is useful to general disinfection in greenhouses and other auxiliary spaces instead formalin having the mutagenic and carcinogenic properties.

  19. Recovery modelling and water resources of the abandoned open-pit talc-chlorite-feldspar mine excavations at Lasasai-Bonucoro,Central Sardinia,Italy%意大利撒丁岛中部Lasasai-Bonucoro地区的废弃露天滑石-绿泥石-长石采矿场的水资源及其修复模式

    Institute of Scientific and Technical Information of China (English)

    Maddalena FIORI; Carlo MATZUZZI

    2004-01-01

    In the district of Orani, central Sardinia, several talc-chlorite-feldspar bodies, hosted in Palaeozoic metamorphic rocks and granites, have long been mined by open- pit operations. The mining activity has deeply modified the original landscape of the Lasasai-Bonucoro area. Thus the rearrangement of this area, in particular of the open-pit works that are now occupied by newly formed pools, filled with water from aquifers flowing along faults crossed by mining operations, should be considered as an overall project of landscape restoration. In the first phase of this work, the environmental and hydrogeological characterisation and the general definition of different zones characterised by different sets of intervention operations has already been made. The following step will include the detailed definition of the different technological interventions to be performed. In order to attain a rehabilitation of this area, first of all the interventions will include: 1) smoothing and re-modelling of local morphology in its still rough sites, namely a few points of the mine benches and dumps, by removing the volumes in excess and settling them again in the hollows, on the base of the indications obtained from opportunely plotted sections; 2) restoration of the removed soil covers, and rehabilitation of the newly formed surfaces after waste disposal, trough re-vegetation techniques including settlement of vegetal soil and nutrients, herbaceous essence hydrosowing, temporary automatic sprinkling; 3) rehabilitation of the corrected slopes, and in general of the remaining poorly vegetated surfaces, trough the above re-vegetation techniques.The above operations will result in a slightly modified plane-altimetrical and landscape arrangement. However these interventions will be sufficient to reach a new environmental qualification, characterised by several opportunities of exploitation. Particular conditions, such as the constant outflow of good-quality water and the amenity of

  20. Transformações químicas, físicas e enzimáticas de goiabas 'PEDRO SATO' tratadas na pós-colheita com cloreto de cálcio e 1-metilciclopropeno e armazenadas sob refrigeração Chemical, physical and enzymatic transformations of guavas 'PEDRO SATO' treated at post-harvest with calcium chlorite and 1-methylciclopropone and stored under refrigeration

    Directory of Open Access Journals (Sweden)

    Lucilia Alves Linhares

    2007-06-01

    Full Text Available Com o objetivo de estudar o efeito dos tratamentos com cloreto de cálcio e com 1-MCP associando-se a refrigeração, na conservação e qualidade de goiabas 'Pedro Sato', conduziu-se o experimento em que frutos dessa cultivar foram tratados com solução de CaCl2 a 2% por 5 minutos e com 1-MCP na concentração de 150 nL/L por 12 horas em câmara hermeticamente fechada. Após os tratamentos, os frutos foram armazenados em câmara refrigerada a 10ºC e 90 ± 2% de umidade relativa, por um período de 25 dias. Os resultados indicaram que os tratamentos foram efetivos em manter a qualidade da fruta, salientando-se os frutos tratados com 1-MCP, que mantiveram uma melhor aparência interna e externa, apresentaram menor perda de massa, maior firmeza, menor síntese de vitamina C, menor solubilização de pectinas e menor atividade enzimática, aumentando desta forma a vida pós-colheita das goiabas.With the purpose of investigating the effect of the treatments with calcium chlorite and with 1-methylcyclopropene, associated with refrigeration, on the conservation and quality of guavas 'Pedro Sato', the experiment was carried out in which the fruit of thiscultivar was treated with a solution of 2% CaCl2 for 5 minutes and with 1-MCP at the concentration of 150 nL/L for 12 hours in a tightly sealed chamber. After the treatments, the fruit was stored in a refrigerated chamber at 10ºC and 90 ± 2% of relative humidity for a 25-days period. The results pointed out that the treatments were effective in maintaining fruit quality, stressing the 1-MCP-treated fruit, which kept a better internal and external appearance, presented less loss of mass, greater firmness, less synthesis of vitamin C, less pectin and less activity enzymatic activity, increasing in this way the post-harvest life of guavas.

  1. Computer simulation of Turing structures in the chlorite-iodide-malonic acid system

    DEFF Research Database (Denmark)

    Jensen, O.; Mosekilde, Erik; Borckmans, P.;

    1996-01-01

    The emergence, growth and stabilization of stationary concentration patterns in a continuously fed chemical reation-diffusion system are studied through numerical simulation of the Lengyel-Epstein model. Using the supply of iodine as a control paramter, the regularity of the hexagonal patterns th...

  2. Controlled clinical evaluations of chlorine dioxide, chlorite and chlorate in man.

    OpenAIRE

    Lubbers, J R; Chauan, S; Bianchine, J. R.

    1982-01-01

    To assess the relative safety of chronically administered chlorine water disinfectants in man, a controlled study was undertaken. The clinical evaluation was conducted in the three phases common to investigational drug studies. Phase I, a rising dose tolerance investigation, examined the acute effects of progressively increasing single doses of chlorine disinfectants to normal healthy adult male volunteers. Phase II considered the impact on normal subjects of daily ingestion of the disinfecta...

  3. USING REDUCING AGENTS TO ELIMINATE CHLORINE DIOXIDE AND CHLORITE ION RESIDUALS IN DRINKING WATER

    Science.gov (United States)

    In an effort to determine the viability of various disinfection alternatives, the Evansville, Ind. Water and Sewer Utility is engaged in a pilot-plant investigation to compare chlorine dioxide and ozone pretreatment. As a result of increased speculation that the total residual c...

  4. High-dose stabilized chlorite matrix WF10 prolongs cardiac xenograft survival in the hamster-to-rat model without inducing ultrastructural or biochemical signs of cardiotoxicity

    DEFF Research Database (Denmark)

    Hansen, A; Kemp, K; Kemp, E;

    2001-01-01

    of high dose WF10 as a single drug regimen in the hamster-to-rat xenotransplantation model and searched for possible cardiotoxic side effects. WF10 prolonged cardiac xenograft survival, but did not induce tolerence or inhibit pathological signs of acute rejection. Hamsters from the donor population...

  5. ClO2-—I-—MA化学振荡反应体系的研究%Research on Chlorite-Iodide-Malonic Acid Oscillatory Reaction Systems

    Institute of Scientific and Technical Information of China (English)

    王芳; 施来顺

    2007-01-01

    目的 探讨出封闭反应器中ClO2-—I-—MA化学振荡体系的振荡规律.方法 采用紫外可见分光光度计在I3-的吸收峰(350 nm)处进行时间扫描,从而得到体系中I3-的浓度随时间的变化规律.结果 检测到比率[ClO2-]0/ [I-]0以及MA的浓度对振荡现象的影响.结论 比率[ClO2-]0/ [I-]0对振荡现象的产生有很大的影响,MA的浓度对振荡现象产生与否影响不大.

  6. 酸碱度对次氯酸钠消毒液杀菌效果影响的研究%Study on the influence of acidity-alkalinity on germicidal efficacy of sodium hypo-chlorite disinfectant

    Institute of Scientific and Technical Information of China (English)

    宋金武; 邓金花; 黎洪周; 林秋婵; 李旺海

    2016-01-01

    目的 观察pH值对次氯酸钠消毒液杀菌效果的影响.方法 采用悬液定量杀菌试验方法,观察pH值对次氯酸钠消毒液杀菌效果的影响.结果 次氯酸钠消毒液pH值在5~12范围内,用有效氯100 mg/L作用10 min,对悬液内大肠杆菌杀灭率达到100%,pH值≥11对金黄色葡萄球菌杀灭率下降.次氯酸钠消毒液pH值在5~12范围内,用有效氯200 mg/L作用10 min,对悬液内铜绿假单胞菌和白色念珠菌杀灭率均为100%.次氯酸钠消毒液pH值在5~9范围内,用有效氯500 mg/L作用60 min,对悬液内枯草杆菌黑色变种芽孢的杀灭率均为100%,pH值≥11,其杀灭枯草杆菌黑色变种芽孢效果下降.结论 次氯酸钠消毒液pH值在9以下对细菌杀灭效果影响不明显,而pH值≥11其杀菌效果有所下降,使用中建议将pH值范围设定在7~9为宜.%Objective To observe the influence of pH value on germicidal efficacy of sodium hypochlorite disinfectant. Methods The suspension quantitative germicidal method was used to observe the influence of pH value on germicidal effi-cacy of sodium hypochlorite disinfectant. Results The killing rates of Escherichia coli exposed to sodium hypochlorite disin-fectant at pH 5~12 with 100 mg/L available chlorine for 10 min were 100%, but the killing rates of Staphylococcus aureus were decreased at pH≥11. The killing rates of Pseudomonas aeruginosa and Candida albicans exposed to sodium hypochlo-rite disinfectant at pH 5~12 with 200 mg/L available chlorine for 10 min were 100%. The killing rates of Bacillus subtilis var. nigar spores exposed to sodium hypochlorite disinfectant at pH 5~9 with 500 mg/L available chlorine for 60 min were 100%, but decreased at pH≥11. Conclusion The pH value below 9 has no obvious influence on germicidal effect for so-dium hypochlorite disinfectant, but the germicidal effect has decreased when pH≥11.

  7. The heat capacities of osumilite from 298.15 to 1000 K, the thermodynamic properties of two natural chlorites to 500 K, and the thermodynamic properties of petalite to 1800 K.

    Science.gov (United States)

    Hemingway, B.S.; Robie, R.A.; Kittrick, J.A.; Grew, E.S.; Nelen, J.A.; London, D.

    1984-01-01

    Modifications to an automated low-T, adiabatic calorimeter are described. Thermodynamic data obtained with this instrument are reported for minerals from metamorphic terrains. (U.S. Bureau of Mines Report of Investigations 8451)-J.A.Z.

  8. Determination of Chlorine Dioxide, Chlorine, Chlorite and Chlorate in Water by Ion Chromatography%用离子色谱法测定水中的二氧化氯、氯、亚氯酸根及氯酸根

    Institute of Scientific and Technical Information of China (English)

    田芳; 谢家理

    2004-01-01

    建立了一种测定水中的ClO2、Cl2、ClO-2、ClO-3离子色谱法,在含有碳酸氢钠缓冲溶液的中性条件下,用NaNO2将ClO2、Cl2还原为ClO-2、Cl-,通过测定ClO-2和NO-3的变化值,间接测定ClO2和Cl2.加入硫代乙酰胺(TAA)作掩蔽剂测定ClO-2.

  9. Efficacy of chlorine, acidic electrolyzed water and aqueous chlorine dioxide solutions to decontaminate Escherichia coli O157:H7 from lettuce leaves

    Science.gov (United States)

    This study compared the efficacy of chlorine (20 – 200 ppm), acidic electrolyzed water (50 ppm chlorine, pH 2.6), acidified sodium chlorite (20 – 200 ppm chlorite ion concentration, Sanova), and aqueous chlorine dioxide (20 – 200 ppm chlorite ion concentration, TriNova) washes in reducing population...

  10. Optimization of dicarboxylic acid cellulose synthesis: reaction stoichiometry and role of hypochlorite scavengers.

    Science.gov (United States)

    Sirviö, Juho Antti; Liimatainen, Henrikki; Visanko, Miikka; Niinimäki, Jouko

    2014-12-19

    The reaction conditions in terms of reaction time, sodium chlorite stoichiometry, and the effect of hypochlorite scavengers on the chlorite oxidation of dialdehyde cellulose (DAC) was studied. The impact of storage on the reactivity of DAC fibers was also investigated. It was found that chlorite oxidation of DAC is a rapid reaction, resulting in oxidation of 71% of the aldehyde after only 8 min when 2.5 times excess of sodium chlorite compared to aldehyde groups was used. Reactivity of DAC was observed to decrease quickly during the storage and only 68% of the aldehyde groups reacted after two weeks storage compared to the reaction performed with freshly prepared DAC. Hydrogen peroxide and sulfamic acid were observed to increase the reaction efficiency of chlorite oxidation by reducing the amount of side-reactions between chlorite and hypochlorite. A minor amount of sulfamic acid can be used to replace acetic acid as a catalyst. PMID:25263866

  11. Clays at the natural nuclear reactor at Bangombe, Gabon: migration of actinides

    International Nuclear Information System (INIS)

    Clay minerals were examined from the natural nuclear reactor at Bangombe. The clay mineralogy of the reactor facies is: illite, kaolinite and minor chlorite (FB formation); illite with chlorite and kaolinite in hydrothermal veins (argile de pile); illite and chlorite (reactor core); and (i) chlorite and kaolinite ± illite ± smectite or (ii) illite in the underlying FA formation. Illite crystallinity values are in general highest in rocks that experienced the highest temperatures during reactor operation. Chlorite chemistry varies with respect to position around the reactor: both di-tri and trioctahedral chlorites are present in hydrothermal veins within the argile de pile, dioctahedral chlorites are present in the FA formation within cm of the reactor core, trioctahedral chlorites are present within a meter of the reactor. Chemical data for the argile de pile and the FB formation suggest that formation of the former unit occurred as a result of thermal metamorphism of the FB pelites, as opposed to large-scale dissolution of the sandstones of the FA formation. Autoradiography is used to study the sorptive characteristics of the clays for actinides. The results show that actinide sorption varies in the order: chlorite > illite ≅ kaolinite. (orig.)

  12. OVERVIEW OF DRINKING WATER MUTAGENICITY AND CARCINOGENICITY AND RISK FOR BLADDER CANCER

    Science.gov (United States)

    Among the 11 disinfection by-products (DBPs) in drinking water that are regulated by the U.S. EPA, (a) 2 DBPs (chloroacetic acid and chlorite) are not carcinogenic-in either of 2 species; (b) chlorite is not carcinogenic in 3 rodent assays and has never been tested for genotoxici...

  13. Uranium deposits of the Grants, New Mexico mineral belt (II). [Genesis

    Energy Technology Data Exchange (ETDEWEB)

    Brookins, D.G.

    1979-07-01

    This is part of a study of the genesis of the U deposits of the Grants mineral belt. Enrichment of Mg in ore zones is frequently observed, with chlorite being a common product. Clay mineralogic studies argue for chlorite-illite-montmorillonite associations with ores. The methods include scanning electron microscopy, Eh-pH diagrams, activation analysis, and rare earth element studies. (DLC)

  14. Uranium deposits of the Grants, New Mexico mineral belt (II)

    International Nuclear Information System (INIS)

    This is part of a study of the genesis of the U deposits of the Grants mineral belt. Enrichment of Mg in ore zones is frequently observed, with chlorite being a common product. Clay mineralogic studies argue for chlorite-illite-montmorillonite associations with ores. The methods include scanning electron microscopy, Eh-pH diagrams, activation analysis, and rare earth element studies

  15. Chloriet, chloraat en bromaat in drink- en oppervlaktewater: Voorkomen, herkomst en gezondheidsaspecten

    NARCIS (Netherlands)

    Versteegh JFM; Neele J; Cleven RFMJ

    1992-01-01

    Chlorate and chlorite exist in surface water especially in the rivers Meuse and Rhine. The average concentration of chlorite and chlorate in river water varies from 10 - 40 mug/l during the six months monitoring program in 1991/1992. The concentrations are lowered during dune infiltration and afte

  16. Late-Quaternary variations in clay minerals along the SW continental margin of India: Evidence of climatic variations

    Digital Repository Service at National Institute of Oceanography (India)

    Chauhan, O.S.; Sukhija, B.S.; Gujar, A.R.; Nagabhushanam, P.; Paropkari, A.L.

    Down-core variations in illite, chlorite, smectite and kaolinite (the major clays) in two sup(14)C-dated cores collected along the SW continental margin of India show that illite and chlorite have enhanced abundance during 20-17, 12.5, 11-9.5, and 5...

  17. Alligator Rivers Analogue project. Weathering and its effects on uranium redistribution

    International Nuclear Information System (INIS)

    In the vicinity of the uranium ore deposit at Koongarra, quartz-chlorite schist, the ore host rock, has been subjected to weathering. Although quartz is resistant to weathering, chlorite has been altered to clays and iron minerals. The chlorite weathering and the uranium association with the weathered minerals are the main topics of this study. In order to clarify the weathering of chlorite and its effects on the redistribution of uranium, the processes, mechanisms, and kinetics of the chlorite weathering, and the uranium concentrations in minerals were examined by various methods: X-ray diffraction analysis, scanning electron microscopy, electron microprobe analysis, transmission electron microscopy, autoradiography, visible spectroscopy, alpha and gamma spectrometry. The observed results were compared to those calculated, based on two different models developed for the present study. Water-rock interactions have resulted in the weathering of chlorite and precipitation and sorption of uranyl from the groundwaters with the weathering products. It is concluded that the chlorite weathering affects the uranium retardation factor, and thus uranium redistribution at Koongarra. 55 refs., 20 tabs., 120 figs

  18. Analysis of mechanical behavior of soft rocks and stability control in deep tunnels

    Directory of Open Access Journals (Sweden)

    Hui Zhou

    2014-06-01

    Full Text Available Due to the weakness in mechanical properties of chlorite schist and the high in situ stress in Jinping II hydropower station, the rock mass surrounding the diversion tunnels located in chlorite schist was observed with extremely large deformations. This may significantly increase the risk of tunnel instability during excavation. In order to assess the stability of the diversion tunnels laboratory tests were carried out in association with the petrophysical properties, mechanical behaviors and water-weakening properties of chlorite schist. The continuous deformation of surrounding rock mass, the destruction of the support structure and a large-scale collapse induced by the weak chlorite schist and high in situ stress were analyzed. The distributions of compressive deformation in the excavation zone with large deformations were also studied. In this regard, two reinforcement schemes for the excavation of diversion tunnel bottom section were proposed accordingly. This study could offer theoretical basis for deep tunnel construction in similar geological conditions.

  19. Study on the removal of NOx from simulated flue gas using acidic NaClO2 solution

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The study on the removal of NOx from simulated flue gas has been carried out in lab-scale bubbling reactor using acidic solutions of sodium chlorite. Experiments were performed at various pH values and inlet NO concentrations in absence as well as presence of SO2 gas at 45oC. The effect of SO2 on NO oxidation and NO2 absorption was critically examined. The oxidative ability of sodium chlorite was investigated at different pH values and it was found to be a better oxidant at a pH less than 4. In acidic medium, sodium chlorite decomposed into ClO2 gas, which is believed to participate in NO oxidation as well as in NO2 absorption. A plausible NOx removal mechanism using acidic sodium chlorite solution has been postulated. A maximum NOx removal efficiency of about 81% has been achieved.

  20. Analysis of mechanical behavior of soft rocks and stability control in deep tunnels

    Institute of Scientific and Technical Information of China (English)

    Hui Zhou; Chuanqing Zhang; Zhen Li; Dawei Hu; Jing Hou

    2014-01-01

    Due to the weakness in mechanical properties of chlorite schist and the high in situ stress in Jinping II hydropower station, the rock mass surrounding the diversion tunnels located in chlorite schist was observed with extremely large deformations. This may significantly increase the risk of tunnel instability during excavation. In order to assess the stability of the diversion tunnels laboratory tests were carried out in association with the petrophysical properties, mechanical behaviors and water-weakening properties of chlorite schist. The continuous deformation of surrounding rock mass, the destruction of the support structure and a large-scale collapse induced by the weak chlorite schist and high in situ stress were analyzed. The distributions of compressive deformation in the excavation zone with large deformations were also studied. In this regard, two reinforcement schemes for the excavation of diversion tunnel bottom section were proposed accordingly. This study could offer theoretical basis for deep tunnel construction in similar geological conditions.

  1. Aeolian deposition of Arabia and Somalia sediments on the southwestern continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Chauhan, O.S.

    Kaolinite, smectite, illite and chlorite as major clay minerals and palygorskite and gibbsite in minor quantities have been recorded from the slope of southwestern continental margin of India. Contribution of kaolinite, smectite and gibbsite is from...

  2. 長崎県耕地土壌粘土鉱物地図の作成と利活用

    OpenAIRE

    江頭, 和彦; 中島, 征志郎; 磯田, 雅子

    1997-01-01

    The clay mineralogical map of cultivated soils of Nagasaki prefecture was prepared based on the analytical data of the clay content and clay mineralogical composition of surface soils of paddy fields, upland fields, and lands under perennial crops throughout the prefecture. Following eight categories were used as mapping units: “smectite-dominant”, “smectite-abundant”, “chlorite/mica/vermiculite/intergrade mineral-type(I)“, “chlorite/mica/vermiculite/intergrade mineral-type(II)“, “kaolin mine...

  3. Chlorine dioxide by-products in drinking water and their control by powdered activated carbon

    OpenAIRE

    Grabeel, Margaret N.

    1992-01-01

    The concentrations of chlorine dioxide (CI02), chlorine, chlorite (CIO2), and chlorate (CI03) were evaluated following pretreatment of raw water by CI02 at water treatment plants in New Castle, Pennsylvania; Charleston, West Virginia; Skagit, Washington; and Columbus, Georgia. Chlorite and chlorate concentrations were unaffected by any of the water treatment processes and did not vary as a function of time of travel in the distribution system. Chlorine dioxide, which was ana...

  4. Hidrólise enzimática de casca de arroz utilizando-se celulases: efeito de tratamentos químicos e fotoquímicos Enzymatic hydrolysis of rice hull using cellulases: effect of chemical and photochemical treatments

    OpenAIRE

    Juan Reyes; Patricio Peralta-Zamora; Nelson Durán

    1998-01-01

    In the present work we reported the study of rice hull enzymatic hydrolysis using a commercial cellulase preparation. The results showed that previous treatment with light and sodium chlorite inhibits the enzymatic process (31.4 and 11.8%, respectively) while hydrogen peroxide and ozone favoured the enzymatic production of reducing sugars (5.9 and 54.9%, respectively). Studies performed by quimiluminescence showed that the chlorite treatment produced the most significant change in the structu...

  5. Reorientation mechanisms of phyllosilicates in the mudstone-to-slate transition at Lehigh Gap, Pennsylvania

    Science.gov (United States)

    Ho, Nei-Che; Peacor, Donald R.; van der Pluijm, Ben A.

    1995-03-01

    The mudstone-to-slate transition of the Martinsburg Formation at Lehigh Gap, Pennsylvania, was re-examined using a new transmission-mode X-ray texture goniometer, supplemented by SEM, XRD, and optical studies. Three mesoscopic zones are recognized in the outcrop: (I) mudstone, (II) transition, and (III) slate zone. In the mudstone zone, the mica basal planes are parallel to bedding whereas the preferred orientation of the chlorite basal planes is up to 30° shallower than bedding. The angular difference between chlorite and mica decreases towards the transition zone, becoming subparallel at ca. 50 m from the contact with the overlying Shawangunk Formation. In the transition zone, the preferred orientations of both mica and chlorite are intermediate to bedding and cleavage orientations, which is consistent with mechanical reorientation of phyllosilicates. This is supported by a decrease in March strain with a minimum at ca. 95 m from the contact for both mica and chlorite. SEM observations similarly show the importance of grain rotation in large detrital grains. In the slate zone, both chlorite and mica orientations are parallel to cleavage. Chlorite and mica in the cleavage orientation of the slate zone have high Fe contents, whereas low-Fe mica and Mg > Fe chlorite dominate in the mudstone and transition zone, which indicates that dissolution-neocrystallization is the dominant mechanism in the slate zone. Thus, mechanical rotation of large detrital grains is important in the early stages of cleavage development, with dissolution—neocrystallization occurring at all stages and becoming dominant in the more evolved stages.

  6. 3D modelling of hydrothermal alteration associated with VHMS deposits in the Kristineberg area, Skellefte district, northern Sweden

    Science.gov (United States)

    Chmielowski, Riia M.; Jansson, Nils; Persson, Mac Fjellerad; Fagerström, Pia

    2016-01-01

    This contribution presents a 3D assessment of metamorphosed and deformed, hydrothermally altered volcanic rocks, hosting the massive sulphide deposits of the Kristineberg area in the 1.9 Ga Skellefte mining district in northern Sweden, using six calculated alteration parameters: the Ishikawa alteration index, the chlorite-carbonate-pyrite index and calculated net mass changes in MgO, SiO2, Na2O and Ba. The results, which are also available as film clips in the Supplementary data, confirm inferences from geological mapping; namely that the sericite- and chlorite-rich alteration zones have complex and cross-cutting geometries and that most of these zones are semi-regional in extent and range continuously from surface to over a kilometre deep. The major known massive sulphide deposits occur proximal to zones characterised by coincidence of high values for the alteration index and chlorite-carbonate-pyrite index and large MgO gains, which corresponds to zones rich in magnesian silicates. These zones are interpreted as the original chlorite-rich, proximal parts the alteration systems, and form anomalies extending up to 400 m away from the sulphide lenses. In addition, the stratigraphically highest VHMS are hosted by rocks rich in tremolite, talc, chlorite and dolomite with lesser clinozoisite, which have high chlorite-carbonate-pyrite index and low-medium alteration index values, reflecting a greater importance of some chlorite-carbonate alteration at this stratigraphic level. Vectoring towards massive sulphide deposits in this area can be improved by combining the AI and CCPI indexes with calculated mass changes for key mobile elements. Of the ones modelled in this study, MgO and SiO2 appear to be the most useful.

  7. Modelling study on uranium migration in rocks under weathering condition

    International Nuclear Information System (INIS)

    A modelling study has been completed to understand the effect of rock alteration on uranium migration at the Koongarra ore deposit, Australia. The model considers the weathering process, the mechanism and rate of chlorite alteration, a major mineral of the host rock, and assumes the presence of reversible sorption sites of chlorite and the presence of reversible and irreversible sorption sites of the weathering products. One- and two-dimensional, calculated uranium concentrations were compared with those observed. Good agreement between the calculated and observed uranium concentration profiles was obtained only when an appropriate fraction of uranium is fixed to the irreversible sorption sites of Fe-minerals produced during weathering of chlorite. On the other hand, the conventional Kd model failed to estimate an adequate uranium concentration profile. The results suggest that the fixation of uranium to Fe-minerals has dominated the migration of uranium in the vicinity of the Koongarra ore deposit

  8. Mineralogy and geochemistry of base-metal deposits at Halilar area, NW Turkey

    Science.gov (United States)

    Kiran Yildirim, D.; Abdelnasser, A.; Doner, Z.; Kumral, M.

    2015-12-01

    This study focuses on the base-metal deposits at Halilar area (NW Turkey) by reporting new data obtained from mineralogical, petrographical and geochemical investigation of this deposit. It is to determine key features of the host rocks, mineralogical changes and alteration zones related to this mineralization. Halilar area is located about 25-30 km NE of Edremit in Balikseir district (NW Turkey). This area contains Halilar group that overlies pre-Late Triassic metamorphic rocks and Permian limestone in the surrounding areas. This Halilar group consists of Bagcagiz and Sakarkaya Formations; later intruded by Duztarla granitic rocks. The base metal deposits at study area represent locally Cu-Pb with some Zn vein type deposits. These deposits restricted to fault gouge zone directed NE-SW as well as occurred at the lower boundary of Bagcagiz and Duztarla granite. It also closely associated with intense hydrothermal alteration within brecciation, and quartz stockwork veining. The mineral assemblage includes chalcopyrite, galena, and some sphalerite, with covellite, and goethite in an abundant gangue of quartz and pyrite. Paragenetic relationships reveal three stages of mineralization; pre-ore, ore, and supergene. Wall-rock hydrothermal alteration includes pervasive silicification, sulfidation, carbonatization, and selective chloritization, sericitization and muscovitization. The geochemical studies refer to the altered samples have high CIA relative to the least altered rocks. The relationship between Na2O and K2O with the Ishikawa alteration index refers to the data plot close to chlorite/sericite. Also, based on alteration box plotting (Ishikawa alteration index vs. chlorite-carbonate-pyrite index), they mostly plotted in the field of the hydrothermal alteration close to chlorite and pyrite minerals with more hydrothermal trends; Intense sericite-chlorite ± pyrite alteration, chlorite ± sericite ± pyrite alteration, and sericite-carbonate alteration.

  9. Uruguay geology contributions no. 4

    International Nuclear Information System (INIS)

    Sedimentary facies: the metasiltites and mela sandstones develop granoblastic textures. The present lepidoblastic textures in flexured bands of seri cite and/or chlorite, a fine qranoblastic matrix made by quartz-feldespaths. The carbonates develop mosaic textures with big crystals of calcites and dolomite, generally elongated following metamorphic foliation (seri cite/chlorite). The quartzites develop qranoblastic textures, with few minerals. Volcanics facies: the basic volcanics presents doleritic intersect al textural, that exist saussuritized plagioclase and albitic diabasa with diopside-augite beaches. Usually the pyroxenes develop poiquilitic textural. Present amphiboles of the acti note series and frequently sphene. Others basic rocks are microlitio porfiric, in intersect al or fluidal matrix, with albite microliters in epi dote-chlorite-acti note criploerislalline ground.The stability relationships of the diferents types of basic metavulcanites show low metamorphic facies, with temperatures under 530-550 grades C, being the most Irequenl association: albite+actinote+chlorite+epidote+opaques- opaques.The clastic faciest are integrated by monogenic breccia with elements of varied vulcanites and porfiric rnicrolitic texture. The matrix is made of line quartz and epidote aggregate. The basic volcanism present hyalo-porfiric textures with saussuritized plagiodase pheno crystals, and quartz in a micro lo criptocrystalline ground. Were also defined rocks with porfiric texture in a piromeritic ground as well as rocks with vacuolar microlitic texture.The clastic facies are made by breccias with sharp elements, with rare cement, integrated by pyroclastic products, The volcanics rocks present retrometamorphism of the phenocrystals and devitrification. The plagioclase are traslormated in fine aggregates of albite epidote. The regional metamorphism minerals are represented by the para genesis: quartz+albite+chlorite+epidote+(seri cite-actinole), subfacies quartz albite-chlorite

  10. The Management and Classification of the Typical Soils of the Yıldız Forest Ecosystem

    OpenAIRE

    Cangir, C.; D. Boyraz

    2009-01-01

    The soils of the Yıldız Mountain, namely Entisols, Mollisols, Inceptisols, Ultisols, and Spodosols, from Poyralı, Yeniceköy, Demirköy and northwest of Igneada that were developed on calcareous sandy sediments, chlorite schists, Pliocene sediments and alluvial materials were studied in this paper. Moreover, the Entisols and the Mollisols located at the Kırklareli, Koruköy, Dereköy and the land up to the Bulgarian border developed on metagranites, quartz-quartzitic sediments, chlorite schists, ...

  11. Heavy sediment influx during early Holocene: Inference from clay mineral studies in a core from the western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Reddy, N.P.C.; Rao, K.M.

    % from the core top to 380 cm and further do wn, increases to 85%. Montmorillonite content ranges from 22 to 36% above 380 cm, with a max i mum in the upper 20 cm. Lowest values of mon t morillonite (3 ? 8%) are observed below 380 cm. Chlorite... from 49 to 65% and mon t morillonite content varies from 22 to 36%, with a max i mum in the upper 20 cm. Chlorite ranges between 13 and 17%. The M/I ratio increases from 0.30 to 0.75 up core from the boundary, indicating stead y i n crease in mon...

  12. Mineralogical, IR-spectral and geochemical monitoring of hydrothermal alteration in a deformed and metamorphosed Jurassic VMS deposit at Arroyo Rojo, Tierra del Fuego, Argentina

    Science.gov (United States)

    Biel, C.; Subías, I.; Acevedo, R. D.; Yusta, I.; Velasco, F.

    2012-04-01

    The Arroyo Rojo Zn-Pb-Cu volcanogenic massive sulfide deposit is the main deposit of the Fin del Mundo District in the Fuegian Andes, Argentina. This deposit is hosted by a Middle Jurassic volcanic and volcanoclastic sequence forming the Lemaire Formation. The latter consists, from the base up, of the following: rhyolitic and dacitic porphyritic rocks, ignimbrite, tuff, and flow. It is underlain by a pre-Jurassic basement and overlain by the hyaloclastic andesites of the Yahgán Formation. The Arroyo Rojo consists of stacked lenticular lenses that are associated with disseminated mineralization in both the footwall and the hanging wall. The internal structure of the ore lenses is marked by the occurrence of massive, semi-massive and banded facies, along with stringer and brecciated zones and minor ore disseminations. The mineral assemblage comprises mainly pyrite and sphalerite, with minor amounts of galena and chalcopyrite and rare pyrrhotite, arsenopyrite, tetrahedrite and bournonite. The ores and the volcanic host rocks have metamorphosed to greenschist facies and were overprinted by a penetrative tectonic foliation, which led to the development of mylonitic, and cataclastic textures, recrystallization and remobilization. Primary depositional characteristics and regional and hydrothermal alteration patterns were preserved despite deformation and metamorphism. Therefore, primary banding was preserved between facies boundaries. In addition, some remnants of magmatic origin are recognizable in preserved phenocrysts and volcaniclastic phenoclasts. Most of the volcanic and volcaniclastic rocks of the host sequence show a rhyolitic to rhyo-dacitic composition. Regional seafloor alteration, characterized by the presence of clinozoisite, Fe-chlorite and titanite, along with quartz and albite, is partially obliterated by hydrothermal alteration. The hydrothermal alteration is stratabound with the following assemblages, which developed from the base to top: (1) Quartz-Chlorite

  13. Clay vein and its implication for uranium exploration activity in the northern part of the Alligator Rivers Uranium Field, northern Australia

    International Nuclear Information System (INIS)

    Clay veins have been found by uranium exploration drilling around the Black Rock uranium prospect in the northern part of the alligator Rivers Uranium Field (ARUF), northern Australia. The mineralogical and chemical features are described to clarify relations with uranium mineralization, because it is not accompanied by uranium mineralization. X-ray diffraction and chemical analysis for major elements indicate that the clay vein consists mainly of chlorite (clinochlore to ferroan clinochlore) and lesser mica clay mineral (t-1M dominant). The clay vein is compared with the clay alteration zone around the uranium deposits in ARUF in terms of mode of occurrence, mineral and chemical compositions. Mineral composition of the clay vein is only in accordance with that of the inner alteration halo of the clay alteration zone. It is, however, different from mineral composition of the outer alteration halo in terms of lack of Fe chlorite in the clay vein. Chemical composition of the clay vein is similar to that of the clay alteration zone, except for lack in the vein of high iron content which is observed in some samples of the alteration zone. As a whole, the feature of the clay vein corresponds to the inner alteration zone around the uranium deposit in ARUF. The mode of occurrence of the clay vein is very different from that of the clay alteration zone. Mode of occurrence, and mineral and chemical compositions of the clay vein resemble a chlorite vein in the Lower to Middle Proterozoic sandstone above the Jabiluka deposit, one of major uranium deposit in the ARUF. Because of the similarity between the clay and the chlorite veins, the clay vein is regarded as marginal facies of an alteration zone. The fluid that formed the clay vein is estimated to have been oxidized, because of the existence of hematite and ubiquitous Mg chlorite. This nature is in accordance with the mineralizing fluid that formed the inner alteration zone in the Nabarlek deposit. In conclusion, the vein

  14. Changing sedimentary environment during the late Quaternary: Sedimentological and isotopic evidence from the distal Bengal Fan

    Digital Repository Service at National Institute of Oceanography (India)

    Kessarkar, P.M.; Rao, V.P.; Ahmad, S.M.; Patil, S.K.; AnilKumar, A.; AnilBabu, G.; Chakraborty, S.; SounderRajan, R.

    sediments are predominantly olive black/grey in colour with abundant finer silt-size fractions, low organic carbon and CaCO sub(3), quartz and mica in the coarse fraction, dominant illite and chlorite in the less than 2 Mu m fraction and uniform rock...

  15. Indian summer monsoon and winter hydrographic variations over past millennia resolved by clay sedimentation

    Science.gov (United States)

    Chauhan, Onkar S.; Dayal, A. M.; Basavaiah, Nathani; Kader, U. Syed Abdul

    2010-09-01

    Reconstruction of century-scale Indian monsoon and winter hydrography is made from an AMS-dated core located in the unique region of the southeast Arabian Sea which lies in the pathways of the low-salinity Bay of Bengal Waters, advecting during winter northeast monsoon (NEM). Based upon clay mineral analyses in seawaters, we identify chlorite and kaolinite as specific clays supplied by the Bay of Bengal Waters and local fluvial flux (by the southwest monsoon (SWM) precipitation from the Peninsular India), respectively, along the southwest continental margin of India. An evaluation of clay flux and δ18O in G. ruber portrays century-scale weaker SWM precipitation events during ˜450-650 yr, ˜1000 yr, and 1800-2200 cal yr BP. Kaolinite wt % and flux were found to be low during all these events, though chlorite had a persistent or enhanced flux. From the enhanced flux of chlorite and reduced kaolinite/chlorite ratio, during weaker phases of SWM, we deduce a stronger NEM (winter hydrography), implying an inverse coupling between the summer and the winter monsoon.

  16. Provenance of Holocene sediment on the Chukchi-Alaskan margin based on combined diffuse spectral reflectance and quantitative X-Ray Diffraction analysis

    Science.gov (United States)

    Ortiz, J.D.; Polyak, L.; Grebmeier, J.M.; Darby, D.; Eberl, D.D.; Naidu, S.; Nof, D.

    2009-01-01

    Sediment clay and silt mineral assemblages provide an excellent means of assessing the provenance of fine-grained Arctic sediment especially when a unique mineral assemblage can be tied to specific source areas. The diffuse spectral reflectance (DSR) first derivative measurements and quantitative X-Ray Diffraction (qXRD) on a high-resolution sediment core from the continental slope north of Alaska constrain the sediment mineralogy. DSR results are augmented by measurements on several adjacent cores and compared to surface sediment samples from the northern Alaskan shelf and slope. Using Principal Component Analysis (PCA), we infer that the three leading DSR modes relate to mixtures of smectite + dolomite, illite + goethite, and chlorite + muscovite. This interpretation is consistent with the down core qXRD results. While the smectite + dolomite, and illite + goethite factors show increased variability down core, the chlorite + muscovite factor had highest positive loadings in the middle Holocene, between ca. 6.0 and 3.6??ka. Because the most likely source of the chlorite + muscovite suite in this vicinity lies in the North Pacific, we argue that the oscillations in chlorite + muscovite values likely reflect an increase in the inflow of Pacific water to the Arctic through the Bering Strait. The time interval of this event is associated in other parts of the globe with a non-linear response of the climate system to the decrease in insolation, which may be related to changes in water exchange between the Pacific and Arctic Ocean. ?? 2009 Elsevier B.V.

  17. Quaternary clay mineralogy in the northern South China Sea (ODP Site 1146)--Implications for oceanic current transport and East Asian monsoon evolution

    Institute of Scientific and Technical Information of China (English)

    LIU Zhifei(刘志飞); Alain Trentesaux; Steven C. Clemens; WANG Pinxian(汪品先)

    2003-01-01

    Measurement of clay mineralogy at ODP Site 1146 in the northern South China Sea (SCS) indicates that illite, chlorite, and kaolinite contents increased during glacials and smectite content increased during interglacials. The smectite/(illite+chlorite) ratio and the smectite abundance were determined as mineralogical indicators for the East Asian monsoon evolution. At a 10 ka timescale, prevailing southeasterly surface oceanic currents during interglacials transported more smectite from the south and east areas to the north, showing a strengthened summer monsoon circulation, whereas dominated counter-clockwise surface currents during glacials carried more illite and chlorite from Taiwan as well as from the Yangtze River via the Luzon Strait to the northern SCS, indicating a strongly intensified winter monsoon. Based on a 100 ka timescale, a linear correlation between the smectite/(illite+chlorite) ratio and the sedimentation rate reflects that the winter monsoon has prevailed in the northern SCS in the intervals 2000-1200 ka and 400-0 ka and the summer monsoon did the same in the interval 1200-400 ka. The evolution of the summer monsoon provides an almost linear response to the summer insolation of Northern Hemisphere, implying an astronomical forcing of the East Asian monsoon evolution.

  18. Clay mineral stratigraphy of Miocene to recent marine sediments in the central Mediterranean

    NARCIS (Netherlands)

    Visser, J.P. de

    1992-01-01

    X-ray diffraction analyses were made of the smaller than 2 J..Lm fraction from about 1250 samples of the central Mediterranean Miocene to Recent and the southeastern North-Atlantic Miocene in order to reconstruct climatic changes. Relative quantities of the clay minerals chlorite, illite, pyrophylli

  19. Petrophysics of shale intervals in the Skjold Field, Danish North Sea

    DEFF Research Database (Denmark)

    Mbia, Ernest Ncha; Fabricius, Ida Lykke; Oji, C. O.

    2011-01-01

    interval 6 is mainly shale. X-ray diffraction analysis reveals the dominance of inter-layered smectite/illite in interval 1–3 and upper part of interval 4, whereas illite dominates interval 5 and 6. Other minerals include kaolinite, chlorite, quartz, calcite, Opal-CT, dolomite and plagioclase...

  20. Evaluation of an experimental sodium chlorate product, with and without nitroethane, on Salmonella in cull dairy cattle

    Science.gov (United States)

    Ruminant animals are natural reservoirs for Salmonella. These bacteria can reduce nitrate to nitrite through the membrane bound enzyme nitrate reductase which also has the ability to reduce chlorate to the cytotoxic end-product chlorite. An experimental product containing sodium chlorate (ECP) has...

  1. Petrofabrics, microtextures and dislocation substructures of olivine in a peridotite mylonite (Alpe Arami, Switzerland)

    NARCIS (Netherlands)

    Buiskool Toxopeus, J.M.A.

    1978-01-01

    The development of preferred crystallographic orientation and dimensional fabric of olivine in relation to deformation were investigated in a thin, continuous chlorite peridotite mylonite rim around the garnet peridotite body of Alpe Arami, Ticino, Switzerland. The mylonite is a foliated rock contai

  2. 75 FR 68505 - National Organic Program; Proposed Amendments to the National List of Allowed and Prohibited...

    Science.gov (United States)

    2010-11-08

    ... synthetically-derived substances: Clay-treated microcrystalline wax (CAS 64742-42-3), petrolatum (CAS 8009-03-08), and paraffin wax (CAS 8002-74-2). Clay-treated microcrystalline wax, petrolatum and paraffin waxes... chlorite); and (3) 73 FR 18491, April 4, 2008, (microcrystalline cheesewax, acidified sodium...

  3. Chemical petrology of polymetamorphic ultramafic rocks from Galicia, NW Spain

    NARCIS (Netherlands)

    Maaskant, P.

    1970-01-01

    The investigated polymetamorphic peridotites occur associated with metabasic rocks in several complexes of probably Precambrian age in the northern part of the Hesperian massif (Iberian peninsula). Spinel-clinopyroxene-, spinel-pargasite-, spinel-hornblende- and chlorite-amphibole-peridotites, wehrl

  4. Development of chlorine dioxide releasing film and its application in decontaminating fresh produce

    Science.gov (United States)

    A feasibility study was conducted to develop chlorine dioxide releasing packaging films for decontaminating fresh produce. Sodium chlorite and citric acid powder were incorporated into polylactic acid (PLA) polymer. Films made with different amount of PLA (100 & 300 mg), percentage of reactant (5-60...

  5. A new occurrence of ambient inclusion trails from the ~1900-million-year-old Gunflint Formation, Ontario: nanocharacterization and testing of potential formation mechanisms.

    Science.gov (United States)

    Wacey, D; Saunders, M; Kong, C; Kilburn, M R

    2016-09-01

    Ambient inclusion trails (AITs) are tubular microstructures thought to form when a microscopic mineral crystal is propelled through a fine-grained rock matrix. Here, we report a new occurrence of AITs from a fossilized microbial mat within the 1878-Ma Gunflint Formation, at Current River, Ontario. The AITs are 1-15 μm in diameter, have pyrite as the propelled crystal, are infilled with chlorite and have been propelled through a microquartz (chert) or chlorite matrix. AITs most commonly originate at the boundary between pyrite- and chlorite-rich laminae and chert-filled fenestrae, with pyrite crystals propelled into the fenestrae. A subset of AITs originate within the fenestrae, rooted either within the chert or within patches of chlorite. Sulphur isotope data ((34) S/(32) S) obtained in situ from AIT pyrite have a δ(34) S of -8.5 to +8.0 ‰, indicating a maximum of ~30 ‰ fractionation from Palaeoproterozoic seawater sulphate (δ(34) S ≈ +20 ‰). Organic carbon is common both at the outer margins of the fenestrae and in patches of chlorite where most AITs originate, and can be found in smaller quantities further along some AITs towards the terminal pyrite grain. We infer that pyrite crystals now found within the AITs formed via the action of heterotrophic sulphate-reducing bacteria during early diagenesis within the microbial mat, as pore waters were becoming depleted in seawater sulphate. Gases derived from this process such as CO2 and H2 S were partially trapped within the microbial mat, helping produce birds-eye fenestrae, while rapid microquartz precipitation closed porosity. We propose that propulsion of the pyrite crystals to form AITs was driven by two complementary mechanisms during burial and low-grade metamorphism: firstly, thermal decomposition of residual organic material providing CO2 , and potentially CH4 , as propulsive gases, plus organic acids to locally dissolve the microquartz matrix; and secondly, reactions involving clay minerals that

  6. The mineralogy and chemistry of fine-grained sediments, Morphou Bay, Cyprus

    Directory of Open Access Journals (Sweden)

    C. Neal

    2002-01-01

    Full Text Available The mineralogy and chemistry of the less than 20μm fraction of marine sediments at Morphou Bay, north-west Cyprus, are presented to characterise fine-grained sediment supplies from basic and ultrabasic rocks of the Troodos Massif within a typological setting. The sediments comprise a mixture of smectite, illite, kaolinite and iron rich chlorite. They also contain amorphous iron oxides/hydroxides, calcite (with some magnesium substitution for calcium and an amphibole. Spatial patterns in mineralogy occur: the near-shore sediments are rich in smectite, chlorite, amphibole and amorphous iron oxides/hydroxides, while the offshore sediments are rich in illite and calcite. The sediments are calcium, magnesium, iron, aluminium and potassium bearing, due to the presence of significant amounts of calcite (for Ca, clay minerals and aluminium and iron oxides/hydroxides. Potassium is present within the micaceous mineral illite, but it is also contained within other phases that are difficult to pinpoint. Statistical analysis reveals that the chemical composition of the sediments broadly follows the mineralogy with the dominant feature being related to spatial changes in the mineralogy. The patterns of change reflect a three component mix of clay-sized sediment types: (1 localised lithogenous sources rich in smectite with subsidiary amounts of amorphous iron oxides/hydroxides and amphibole, from Cyprus, the Troodos in particular, (2 illite rich and smectite chlorite and chlorite bearing material of lithogenous origin from other parts of the eastern Mediterranean and (3 calcite, mainly of marine origin. Keywords: smectite, illite, chlorite, kaolinite, calcite, sediments, Morphou Bay, Troodos, Cyprus, Mediterranean, calcium, potassium, magnesium, iron, silicon, phosphorus.

  7. Geochemical and Mineralogical Characteristics of Pleistocene Lignites and Associated Sediments of Marathousa Coal Field,Central Peloponnese,Greece

    Institute of Scientific and Technical Information of China (English)

    A.E.KELEPERTSIS; E.KONTIS

    1997-01-01

    The mineralogy and geochemistry data are presented for thirty-seven shales,four concretions,two carbonate sediments and seven lignites from the Marathousa coal field of the Megalopolis Basin in Greece.The argillaceous rocks consist of chlorite,illite,kaolinte,albite,quartz.opal-A,calcite and dolomite;the concretions of aragonite,gypsum and pyrite;and the carbonate rocks of calcite,quartz and illite.The mineral matter in the lignites consists of gypsum,quartz,albite,chlorite,illite,opal-A,dolomite,pyrite,and rarely calcite and kaolinite Athree-factor model explains the total variaition of major and trace elements in the argillaceous sediments.The first factor is an aluminosilicate factor and involves the following elements:Al,Si,Mg,Na,K,Ti,Mn,Nb,Y,Rb,Zn,Cu,Ni,Cr,Nband V,associated with chlorite,albite and illite.The second factor involves the elements Ca,Sr,Ba,Znand Sc and is related to carbonate lithology and mainly the carbonate concretions with gypsum.The third factor involves Fe and Ce with a weak association with Mn.The diagenesis of the Marathousa sediments and lignites was not very advanced as indicated by (a) the total thickness of the sequence (500m),(b) the presence of biogenic silica(opal-A) and (c) the age of the deposit(Pleistocene).FOr these reasons the rpresence of chlorite,illite and kaolinite in the sediments and lignite is due not to diagenetic reactions but to weathering of the flysch and metamorphic rocks at the edges of the Megalopolis Basin and transport of the weathering products(illite,chlorite,kaolinite)into the basin of deposition.The diagenetic minerals of the Marathousa sequence include pyrite,gypsum,dolomite and aragonite.

  8. Microscale mapping of alteration conditions and potential biosignatures in basaltic-ultramafic rocks on early Earth and beyond.

    Science.gov (United States)

    Grosch, Eugene G; McLoughlin, Nicola; Lanari, Pierre; Erambert, Muriel; Vidal, Olivier

    2014-03-01

    Subseafloor environments preserved in Archean greenstone belts provide an analogue for investigating potential subsurface habitats on Mars. The c. 3.5-3.4 Ga pillow lava metabasalts of the mid-Archean Barberton greenstone belt, South Africa, have been argued to contain the earliest evidence for microbial subseafloor life. This includes candidate trace fossils in the form of titanite microtextures, and sulfur isotopic signatures of pyrite preserved in metabasaltic glass of the c. 3.472 Ga Hooggenoeg Formation. It has been contended that similar microtextures in altered martian basalts may represent potential extraterrestrial biosignatures of microbe-fluid-rock interaction. But despite numerous studies describing these putative early traces of life, a detailed metamorphic characterization of the microtextures and their host alteration conditions in the ancient pillow lava metabasites is lacking. Here, we present a new nondestructive technique with which to study the in situ metamorphic alteration conditions associated with potential biosignatures in mafic-ultramafic rocks of the Hooggenoeg Formation. Our approach combines quantitative microscale compositional mapping by electron microprobe with inverse thermodynamic modeling to derive low-temperature chlorite crystallization conditions. We found that the titanite microtextures formed under subgreenschist to greenschist facies conditions. Two chlorite temperature groups were identified in the maps surrounding the titanite microtextures and record peak metamorphic conditions at 315 ± 40°C (XFe3+(chlorite) = 25-34%) and lower-temperature chlorite veins/microdomains at T = 210 ± 40°C (lower XFe3+(chlorite) = 40-45%). These results provide the first metamorphic constraints in textural context on the Barberton titanite microtextures and thereby improve our understanding of the local preservation conditions of these potential biosignatures. We suggest that this approach may prove to be an important tool in future

  9. Chlorine dioxine DBPs (disinfection by-products in drinking water

    Directory of Open Access Journals (Sweden)

    C. Lasagna

    2013-01-01

    Full Text Available Since the 1970s it has been well known that, though water for human consumption is generally disinfected before being distributed along the network, the use of chemicals results in the formation of many different Disinfection By-Products (DBPs. In the case of chlorine dioxide, the most important and represented DBPs are chlorite and chlorate: after an introduction concerning the current Italian regulation on this subject, in the experimental part the results of a 7-year minitoring campaign, concerning water of different origin collected from taps in various Italian regions, are shown. The analytical technique used for the determination of chlorite and chlorate was Ion Chromatography. The result obtained are finally discussed.

  10. CO{sub 2} mineral trapping: an experimental study on the carbonation of basalts from the eastern Deccan Volcanic Province, India

    Energy Technology Data Exchange (ETDEWEB)

    Rani, Nishi; Pathak, Vamdev; Shrivastava, J.P. [Department of Geology, University of Delhi, Delhi 110007 (India)

    2013-07-01

    Rock specimens from Deccan flood basalts have been reacted in the laboratory under high pCO{sub 2} (5 and 10 bars), total pressure (vessel pressure between 10 and 20 bars), and temperature (100 and 200 deg. C) conditions for 50, 60, 70, and 80 hours. XRD and SEM-EDS analyses show that calcite, aragonite, siderite and magnesite, and clays are derived from the alteration of Deccan basalts under water-saturated, hydrothermal-like conditions. Alteration reactions were accompanied by significant variation in the pH of the reacting aqueous solution, dependent upon time, pCO{sub 2}, and temperature variables of the experiment. Neo-formed secondary products also include significant amounts of smectite, chlorite, and smectite/chlorite mixed layer clays. (authors)

  11. Rodingitization and carbonization processes in Triassic ultramafic cumulates and lavas, Othris Mt, Central Greece

    Science.gov (United States)

    Koutsovitis, Petros; Magganas, Andreas; Economou, Georgios

    2016-04-01

    A Triassic magmatic sequence from the south Othris region is comprised of early stage basaltic pillow lavas, as well as late stage ultramafic rocks, lava flows, high-Mg doleritic dykes and pyroclastic tuffs. The ultramafic rocks include slightly serpentinized wehrlites and lavas consisting of cumulate olivine, variably textured clinopyroxene (cumulate, quench, hollow, skeletal or blade shaped), magnesiohornblende, tremolite, phlogopite, spinel, chlorite, garnet, serpentine, calcite and devitrified glass[1]. Part of their secondary mineralogy developed due to percolation of metasomatic fluids during rodingitization and carbonization processes. In ultramafic rocks from Agia Marina and Mili, rodingitization was rather penetratively and expressed with crystallization of hydrogarnets, accompanied by secondary diopside and chlorite. Hydrogarnets are characterized by their low Ti-contents (recycling thermal carbonated seawater, leached from the rifted Triassic platform carbonates. References. [1] Koutsovitis, Magganas, Ntaflos 2012: Lithos 144-145, 177-193; [2] Koutsovitis, Magganas, Pomonis, Ntaflos 2013: Lithos 172-173, 139-157.

  12. Diagenetic effect on permeabilities of geothermal sandstone reservoirs

    DEFF Research Database (Denmark)

    Weibel, Rikke; Olivarius, Mette; Kristensen, Lars;

    The Danish subsurface contains abundant sedimentary deposits, which can be utilized for geothermal heating. The Upper Triassic – Lower Jurassic continental-marine sandstones of the Gassum Formation has been utilised as a geothermal reservoir for the Thisted Geothermal Plant since 1984 extracting...... and permeability is caused by increased diagenetic changes of the sandstones due to increased burial depth and temperatures. Therefore, the highest water temperatures typically correspond with the lowest porosities and permeabilities. Especially the permeability is crucial for the performance of the geothermal......-line fractures. Continuous thin chlorite coatings results in less porosity- and permeability-reduction with burial than the general reduction with burial, unless carbonate cemented. Therefore, localities of sandstones characterized by these continuous chlorite coatings may represent fine geothermal reservoirs...

  13. Significance of saturation index of certain clay minerals in shallow coastal groundwater, in and around Kalpakkam, Tamil Nadu, India

    Indian Academy of Sciences (India)

    S Chidambaram; U Karmegam; P Sasidhar; M V Prasanna; R Manivannan; S Arunachalam; S Manikandan; P Anandhan

    2011-10-01

    The saturation index of clay minerals like Gibbsite, Kaolinite, Illite, Montmorillonite and Chlorite in groundwater were studied in detail by collecting 29 groundwater samples from the shallow coastal aquifers in and around Kalpakkam. The samples collected were analysed for major cations, anions and trace elements by using standard procedures. The study reveals that pH has a significant role in the saturation index (SI) of minerals. It also shows that the relationship of electrical conductivity to the SI of these minerals is not significant than that of the ionic strength, log pCO2 values, and alumina silica ratio have significant relation to the SI of these clay minerals. The SI of these clay minerals was spatially distributed to identify the areas of higher SI. Silica has good correlation to SI of Kaolinite, Gibbsite and Montmorillonite and Al has good correlation to SI of all the minerals except to that of Chlorite.

  14. Petrographic report on clay-rich samples from Permian Unit 4 salt, G. Friemel No. 1 well, Palo Duro Basin, Deaf Smith County, Texas: unanalyzed data

    International Nuclear Information System (INIS)

    This report presents the results of mineralogic and petrographic analyses performed on five samples of clay-rich rock from salt-bearing Permian strata sampled by drill core from G. Friemel No. 1 Well, Deaf Smith County, Texas. Five samples of clay-rich rock from depths of about 2457, 2458, 2521, 2548, and 2568 feet were analyzed to determine the amounts of soluble phase (halite) and the amounts and mineralogy of the insoluble phases. The amounts of halite found were 59, 79, 47, 40, and 4 weight percent, respectively, for the samples. The insoluble minerals are predominately clay (20 to 60 volume percent) and anhydrite (up to 17 volume percent), with minor (about 1.0%) and trace amounts of quartz, dolomite, muscovite, and gypsum. The clays include illite, chlorite, and interstratified chlorite-smectite. The results presented in this petrographic report are descriptive, uninterpreted data. 2 references, 7 tables

  15. CLAY MINERAL ASSEMBLAGES AND THEIR IMPLICATIONS IN SHIHEZI FORMATION FROM THE HUAIBEI COAL-BEARING STRATA

    Institute of Scientific and Technical Information of China (English)

    黄文辉; 许光泉; 刑军

    1998-01-01

    Clay mineral assemblages in Shihezi Formation of Huaibei coal-bearing strata are determined by X-ray diffraction and Differential Thermal Analyzer, that is restated to the sedimentfaces and climatic changes in the source area, and to a lesser extent, alterations during burial diagenesis. In the Upper Shihezi Formation, the clay fraction is dominated by kaolinite in norther npart of the coal field, which was formed in alluvial sediment environment. But in the South ofHuaibei coal field, the clay mineral assemblage consists of mainly illite that reflects the influenceof sea water. The predominately kaolinite and sederite composition of the clay fraction in the lower Shihezi Formation sediments documents less relief and gentle erosion of kaolinite rich soils developing under warm source area. In the lower part of Shihezi Formation, some chlorite is detected, which suggests transformation of illite or kaolinite to chlorite under conditions of burial diagenesis.

  16. Clay mineralogy, grain size distribution and their correlations with trace metals in the salt marsh sediments of the Skallingen barrier spit, Danish Wadden Sea

    DEFF Research Database (Denmark)

    He, Changling; Bartholdy, Jesper; Christiansen, Christian

    2012-01-01

    metals. The clay assembly of the sediment consists of illite, kaolinite and much less chlorite and smectite. The major clay minerals of illite, kaolinite as well as chlorite correlate very poorly with all the trace metals investigated, due probably to the weak competing strength of these clays compared...... with the other adsorbents and to low availability of the mobile trace metals in the system. Correlation between trace metals and clay minerals may therefore be used as an indicator in environmental assessment. Fine grain fractions of the sediment increased markedly after salt marsh invasion in about 1931......To understand the behavior of trace metals in the salt marsh at Skallingen, Danish Wadden Sea, we investigated a profile from surface to 25 cm depth of the salt marsh sediment, focusing primarily on clay mineralogy and grain size distribution of the sediments and their relationship with trace...

  17. X-ray diffraction analysis of clay stones, Muglad Sedimentary Basin, Sudan

    International Nuclear Information System (INIS)

    This study deals with the theoretical and experimental aspects of X-ray diffraction (XRD) technique. Moreover the XRD technique has been used to investigate the clay mineral types and their distribution for samples obtained from exploration wells in the Mugald Sedimentary Basin in Western Sudan. The studied samples range in depth from 1524 m to 4572 m. The XRD analysis of samples shows that they consist of kaolinite, smectite, illite, chlorite and the mixed-layer smectite/illite. Kaolinite has higher abundance (15 - 72 %) followed by illite (7 - 34 %), smectite (11 - 76 %) and the less abundance of chlorite and the mixed-layer smectite/illite. Non-clay minerals found include quartz and cristabolite. The clay mineral types and their vertical distribution reflect various controls such as environmental, burial diagenesis, source rocks and climatic influences in the Muglad Sedimentary Basin. (author). 19 refs., 11 figs., 3 tabs

  18. Analysis of oxyhalide disinfection by-products and other anions of interest in drinking water by ion chromatography.

    Science.gov (United States)

    Hautman, D P; Bolyard, M

    1992-06-01

    The US Environmental Protection Agency is developing regulations for various drinking water disinfection by-products (DBPs). This effort involves developing analytical methods for the DBPs formed as a result of different disinfection treatments and collecting occurrence data for these species. Ion chromatography is one method being used to analyze drinking water samples for the following inorganic DBPs: chlorite, chlorate and bromate. These anions, however, are difficult to separate from common interfering anions of chloride, carbonate and nitrate. A method is therefore presented by which tetraborate/boric acid is used to separate these anions. Method detection limits of the order of 10 micrograms/l, using conductivity and UV detection were obtained. Stability studies of chlorite showing the effectiveness of ethylenediamine as a preservative and summary data for an occurrence of nitrite, nitrate and the DBP precursor bromide are presented.

  19. Petrographic report on clay-rich samples from Permian Unit 4 salt, G. Friemel No. 1 well, Palo Duro Basin, Deaf Smith County, Texas: unanalyzed data

    Energy Technology Data Exchange (ETDEWEB)

    Fukui, L M

    1983-09-01

    This report presents the results of mineralogic and petrographic analyses performed on five samples of clay-rich rock from salt-bearing Permian strata sampled by drill core from G. Friemel No. 1 Well, Deaf Smith County, Texas. Five samples of clay-rich rock from depths of about 2457, 2458, 2521, 2548, and 2568 feet were analyzed to determine the amounts of soluble phase (halite) and the amounts and mineralogy of the insoluble phases. The amounts of halite found were 59, 79, 47, 40, and 4 weight percent, respectively, for the samples. The insoluble minerals are predominately clay (20 to 60 volume percent) and anhydrite (up to 17 volume percent), with minor (about 1.0%) and trace amounts of quartz, dolomite, muscovite, and gypsum. The clays include illite, chlorite, and interstratified chlorite-smectite. The results presented in this petrographic report are descriptive, uninterpreted data. 2 references, 7 tables.

  20. COMPOSITION OF MINERAL PHASES OF THE GHIDIRIM DIATOMITE

    OpenAIRE

    Vasile Rusu; Aliona Vrînceanu; Igor Polevoi

    2007-01-01

    Studies of the mineralogical composition of diatomite from the Ghidirim location of RM, as well as of the extracted clay phase are presented. The mineral phase of the diatomite contains a number of clay minerals, like montmorillonite (in a mixture with insignificant quantities of slightly chloritized montmorillonite), illite and kaolinite. Diatomite contains also non-clay components as fine-dispersed quartz and amorphous material, the more probable sources of which are opal, amorphous alumosi...

  1. Distribution of clay minerals in drift sediments on the continental rise west of the Antarctic Peninsula, ODP Leg 178, Sites 1095 and 1096

    OpenAIRE

    Hillenbrand, C.-D.; W. Ehrmann

    2001-01-01

    The clay mineral compositions of upper Miocene to Quaternary sediments recovered at Ocean Drilling Program (ODP) Leg 178, Sites 1095 and 1096, from the continental rise west of the Antarctic Peninsula were analyzed in order to reconstruct the Neogene and Quaternary Antarctic paleoclimate and ice dynamics. The clay mineral assemblages are dominated by smectite, illite, and chlorite. Kaolinite occurs only in trace amounts. Analysis of a surface-sample data set facilitates the assignment of thes...

  2. Mineralogy and chemistry of archaeological ceramic fragments from archaeological Dark Earth site in Colombian Amazon Mineralogia e química de fragmentos cerâmicos arqueológicos em sítio com Terra Preta da Amazônia Colombiana

    OpenAIRE

    Marcondes Lima da Costa; Gaspar Morcote Rios; Mônia Maria Carvalho da Silva; Glayce Jholy da Silva; Uliana Molano-Valdes

    2011-01-01

    Several Archaeological Dark Earth (ADE) sites have been already found in the Colombian Amazon forest showing high content of archaeological ceramic fragments similarly to those in the Brazilian Amazon represented by Quebrada Tacana site. Their fragments are yellow to grey colour, display a burned clayey matrix which involves fragments of cariapé and coal and ash particles, besides grains of quartz and micas. The clay matrix is made of metakaolinite, quartz, and some mica flakes, chlorite and ...

  3. Mineralogy, geochemistry, genesis, and industrial application of silica in Arefi area, south of Mashhad

    OpenAIRE

    Mohammad Hassan Karimpour; Azadeh Malekzadeh Shafaroudi; Saeid Saadat

    2014-01-01

    Introduction Arefi quartz-bearing conglomerate (Middle Jurassic) is situated within Binalud structural zone. The unit is trending NW-SE located 25 km south of Mashhad. More than 97% of the pebbles are quartz as mono-crystalline, poly-crystalline, and minor fragments of chert, quartzite, and mica schist. Less that 3% of the remaining minerals are feldspar, mica, chlorite, hornblende, tourmaline, zircon, sphene, and opaque minerals. The cement is mainly silica. Hashemi (Hashemi, 2004) sugges...

  4. Permeability of sheeted dykes beneath oceanic ridges: Strain experiments coupled with 3D numerical modeling of the Troodos Ophiolite, Cyprus

    OpenAIRE

    Coelho, Gabriel; Branquet, Yannick; Sizaret, Stanislas; Arbaret, Laurent; Champallier, Rémi; Rozenbaum, Olivier

    2015-01-01

    Permeability laboratory measurements under in-situ pressures, temperature and strain have been performed on three different diabase alteration facies (metadiabase, chloritized diabase, epidosite) from the Troodos Ophiolite, Cyprus. This aims to study the relations between hydrodynamics, deformation and hydrothermal reaction in the sheeted dyke complex beneath oceanic ridges. The use of water as pore fluid in these experiments favors hydrothermal fluid-rock interactions. All experiments, perfo...

  5. The first data on paleomagnetism of Palaeoproterozoic rocks of the Serpovidny structure (the Kola region, northeastern Baltic Shield

    Directory of Open Access Journals (Sweden)

    Matyushkin A. V.

    2016-03-01

    Full Text Available The orientation of natural magnetization vector components in amphibolites and amphibole schists (magnetite up to 10 % coincides with that of the modern magnetic field vector. Different orientations have been discovered only in quartzitic gneiss (magnetite ≤ 2 % and regressively changed chlorite-amphibole schist. The palaeopole position determined for these rocks corresponds on the apparent pole wander path to ages of 1.95 Ga and ~1.80 Ga, respectively

  6. Chlorine dioxide and by-products in water distribution systems

    OpenAIRE

    Ferreira, Francisco Cardoso

    1991-01-01

    Chlorine dioxide is used as both a pre-oxidant and/or a post-disinfectant in several water treatment plants in the United States. Chlorine dioxide is associated with its byproducts chlorite and chlorate. Chlorine dioxide, chlorine, chlori te and chlorate were sampled in four distribution systems where chlorine dioxide is used for disinfection purposes: Charleston, WV, Columbus, GA, New Castle, PA, and Skagit, WA. The fate of chlorine dioxide and its by-products in dist...

  7. Disinfecting capabilities of oxychlorine compounds.

    OpenAIRE

    Noss, C I; Olivieri, V P

    1985-01-01

    The bacterial virus f2 was inactivated by chlorine dioxide at acidic, neutral, and alkaline pH values. The rate of inactivation increased with increasing pH. Chlorine dioxide disproportionation products, chlorite and chlorate, were not active disinfectants. As chlorine dioxide solutions were degraded under alkaline conditions, they displayed reduced viricidal effectiveness, thereby confirming the chlorine dioxide free radical as the active disinfecting species.

  8. Tonmineral-Neubildung und Paläosalinität im Unteren Muschelkalk des südlichen Germanischen Beckens

    OpenAIRE

    Ruegner, Oliver

    2000-01-01

    Die Nichtkarbonatfraktion des Unteren Muschelkalks (Mittlere Trias) wurde anhand von sechs Bohrprofilen aus dem südlichen Germanischen Becken mittels konventioneller und isotopen-geochemischer Methoden analysiert. Die Tonfraktion besteht im wesentlichen aus der Mineralphase Illit, daneben kommen Illit-Smektit, Kaolinit und Chlorit vor. In der Tonfraktion wurden Borkonzentrationen zwischen 150 und 275 ppm gemessen. Innerhalb der Muschelkalk-Abfolge lassen sich charakteristische Verteilungsmust...

  9. Clay mineralogical and geochemical constraints on late Pleistocene weathering processes of the Qaidam Basin, northern Tibetan Plateau

    Science.gov (United States)

    Miao, WeiLiang; Fan, QiShun; Wei, HaiCheng; Zhang, XiYing; Ma, HaiZhou

    2016-09-01

    At the Qarhan Salt Lake (QSL) on the central-eastern Qaidam Basin, northern Tibetan Plateau, Quaternary lacustrine sediments have a thickness of over 3000 m and mainly composed of organic-rich clay and silty clay with some silt halite and halite. In this study, a 102-m-long sediment core (ISL1A) was obtained from the QSL. Combining with AMS 14C and 230Th dating, clay minerals and major-element concentrations of ISL1A were used to reconstruct the weathering process and trend of the QSL since late Pleistocene. The results reveal that the clay mineral from rocks, gneisses and schists of Eastern Kunlun Mountains on the south of the QSL. The abundance of illite mineral displays an opposite fluctuation trending with that of smectite, chlorite and kaolinite mineral in ISL1A, which is significantly different from the monsoon-controlled regions. Moreover, higher values of illite, kaolinite/chlorite and illite/chlorite ratios, and lower values of smectite, chlorite and kaolinite minerals occurred in 83-72.5 ka, 68.8-54 ka, 32-24 ka, corresponding to late MIS 5, late MIS 4, early MIS 3 and late MIS 3, respectively. These three phases were almost similarly changed with oxygen isotopes of authigenic carbonates and pollen records in ISL1A, which implies that stronger chemical weathering corresponds to higher effective moisture periods of source region in the Qaidam Basin. Based on chemical weathering index and (Al2O3-(CaO + Na2O)-K2O) diagram, chemical weathering degree in this study area takes a varying process from low to intermediate on the whole.

  10. Fluid flow and polymetallic sulfide mineralization in the Kettara shear zone (Jebilet Massif, Variscan Belt, Morocco)

    Science.gov (United States)

    N'diaye, I.; Essaifi, A.; Dubois, M.; Lacroix, B.; Goodenough, K. M.; Maacha, L.

    2016-07-01

    The Kettara shear zone is a regional wrench shear zone within the Jebilet massif of Western Morocco, part of the Variscan orogenic belt. This massif is characterized by bimodal magmatism, largely intrusive, and by a number of polymetallic massive sulfide deposits. A syntectonic mafic-ultramafic intrusion and an adjacent, deformed pyrrhotite-rich massive sulfide deposit are located within a 'compressional jog' of the shear zone. Hydrothermal alteration in both the intrusion and the wall rocks adjacent to the deposit is characterized by syntectonic replacement processes leading to formation of chlorite-schists and quartz ± calcite veins. Fluid inclusions in mineralized (pyrrhotite-bearing) quartz veins from the wall rocks adjacent to the deposit and in veins associated with chlorite-schists within the intrusion indicate a prevalence of H2O-CO2-CH4-N2 and H2O-salt fluid systems. In the mineralized veins the fluid shows reducing conditions, with gas dominated by CH4 and N2 and salinities around 7.5 wt% NaCl, whereas in the chlorite shear zones fluid is CO2 dominated and salinities are higher than 23 wt% NaCl. Hydrogen and oxygen isotopic compositions of chlorite and quartz are similar and demonstrate involvement of metamorphic water in both the deposit and the intrusion. The data are consistent with a regional metamorphic fluid flow through the Kettara shear zone. The migrating metamorphic fluids were reduced in the organic matter-rich host rocks leading to deposition of sulfides in the mineralized veins. There are two possible hypotheses for the origin of these mineralized veins: either they were formed during deformation and remobilization of a syn-sedimentary massive sulfide deposit, or they were formed synchronously with the sulfide deposit during development of the Kettara shear zone.

  11. High and intermediate sulphidation environment in the same hydrothermal deposit: the example of Au-Cu Palai???Islica deposit, Carboneras (Almer??a)

    OpenAIRE

    Carrillo-Ros??a, Javier; Morales-Ruano, Salvador; Boyce, Adrian J.; Fallick, Anthony E.

    2003-01-01

    Two epithermal environments have been identified in the Miocene Palai???Islica Au???Cu deposit: A) Intermediate sulphidation, hosted mainly in quartz veins, comprises pyrite, chalcopyrite, sphalerite and galena as the major sulphides, which are accompanied by a variety of Ag-bearing accessory minerals. Au???Ag alloys are the only gold-bearing phase. The veins are enclosed by sericitic and chloritic alteration. Fluid inclusions in quartz, sphalerite and calcite give Th between 118???453 ??C, a...

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

    OpenAIRE

    Taghipour Batoul; Ahmadnejad Farhad

    2015-01-01

    The Qolqoleh gold deposit is located in the northwestern part of the Sanandaj–Sirjan Zone (SSZ), within the NE–SW trending Qolqoleh shear zone. Oligocene granitoids, Cretaceous meta-limestones, schists and metavolcanics are the main lithological units. Chondrite-normalised REE patterns of the ore-hosting metavolcanics indicate REE enrichment relative to hanging wall (chlorite-sericite schist) and footwall (meta-limestone) rocks. The pattern also reflects an enrich -ment in LREE re...

  13. Alteration of podzolized tills by acid load near Ni-Cu smelters at Monchegorsk, Kola Peninsula, Russia

    Directory of Open Access Journals (Sweden)

    Räisänen, M.L.

    1994-06-01

    Full Text Available Mineralogy and geochemistry of podzolized tills was studied in the area of dieback forest near the Ni-Cu smelters at Monchegorsk, and less extensively forest damage near by Apatity and Kirovsk in the Russian Kola Peninsula. The abundances of main elements (Si, Al, Fe, Mg, Ca, K, Na in the <64 μm fraction were determined by the hot aqua regia digestion method and inductively coupled plasma spectrometry. The clay mineralogy of the silt plus clay fraction was examined by X-ray diffraction after selective extraction and heating treatments. At all study sites, trioctahedral mica and chlorite were totally weathered from the silt and clay fraction (<64 μm of the eluvial layer, leaving behind interstratified mica-vermiculite-smectite clays. In general, the mixed-layer clay of the eluvial layer had low levels of hydroxy interlayering. Illuviated layers were characterized by hydroxy interlayered vermiculite-chlorite. The abundance of chlorite and mica was greater, and the degree of interlayering lower, in parent tills than in the overlying illuviated layers. Regardless of differences in bedrock and till geochemistry, the weathering sequence throughout the podzolized till profile was coherent at most of the sampling sites. Exceptionally, in a few profiles sampled at the totally destroyed forest site, the swelling mixed-layer clay of the eluvial layer displayed a neochloritized structure. On the basis of XRD patterns and geochemistry of the samples, it was inferred that a short-term decomposition of plagioclase had promoted, via inputs of Al-hydroxides, the transformation of mica-vermiculite-smectite to a poorly crystalline interstratification of chlorite-aluminous montmorillonite. The accelerated weathering occurring occasionally in exposed places was probably activated by the strongly acidic load in the vicinity of the smelters and the city of Monchegorsk.

  14. Perchlorate reduction by microbes inhabiting oil reservoirs

    Science.gov (United States)

    Liebensteiner, Martin; Stams, Alfons; Lomans, Bart

    2014-05-01

    Microbial perchlorate and chlorate reduction is a unique type of anaerobic respiration as during reduction of (per)chlorate chlorite is formed, which is then split into chloride and molecular oxygen. In recent years it was demonstrated that (per)chlorate-reducing bacteria may employ oxygenase-dependent pathways for the degradation of aromatic and aliphatic hydrocarbons. These findings suggested that (per)chlorate may be used as oxygen-releasing compound in anoxic environments that contain hydrocarbons, such as polluted soil sites and oil reservoirs. We started to study perchlorate reduction by microbes possibly inhabiting oil reservoirs. One of the organisms studied was Archaeoglobus fulgidus. This extremely thermophilic archaeon is known as a major contributor to souring in hot oil reservoirs. A. fulgidus turned out to be able to use perchlorate as terminal electron acceptor for growth with lactate (Liebensteiner et al 2013). Genome based physiological experiments indicated that A. fulgidus possesses a novel perchlorate reduction pathway. Perchlorate is first reduced to chlorite, but chlorite is not split into chloride and molecular oxygen as occurs in bacteria. Rather, chlorite reacts chemically with sulfide, forming oxidized sulfur compounds, which are reduced to sulfide in the electron transport chain by the archaeon. The dependence of perchlorate reduction on sulfur compounds could be shown. The implications of our findings as novel strategy for microbiological enhanced oil recovery and for souring mitigation are discussed. Liebensteiner MG, Pinkse MWH, Schaap PJ, Stams AJM and Lomans BP (2013) Archaeal (per)chlorate reduction at high temperature, a matter of abiotic-biotic reactions. Science 340: 85-87

  15. Zoning and contamination rate of magnesium and heavy metals of iron, zinc and copper in the north and northwest aquifer of Khoy (Zourabad) based on GIS and determining the contaminated source

    OpenAIRE

    Fariborz Khodadadi; Abdolnaser Fazlnia; Hossein Pirkharrati

    2015-01-01

    Introduction Heavy metals are the most toxic pollutants in aquatic ecosystems. This contamination can result from the release of heavy metal elements during alteration and weathering of ultramafic and mafic rocks (ophiolite zones). Among the important metals and pollutants in the ophiolite; chromium, cobalt, nickel, iron, magnesium, manganese, zinc and copper could be noted. Basically, a mass of serpentine consists of serpentine, amphibole, talc, chlorite, magnetite, and the remainder of o...

  16. Improving Settling Dynamics of Activated Sludge by Adding Fine Talc Powder

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Larsen, Torben; Clauss, F.

    1996-01-01

    . The settling velocity was measured with a recirculated settling column under different concentrations and turbulence levels. Numerical simulation of a secondary settling tank indicates that adding fine powder will improve the overall performance considerably.......The effect of adding varying mixtures of talc and chlorite powder to activated sludge in order to improve the settling characteristic has been studied. The powder is found to improve the settling velocity of the sludge, strictly by increasing the average density of the sludge floc aggregate...

  17. Chemical composition of Kiscellian silty sediment (sivica from the Trobni Dol area, Eastern Slovenia

    Directory of Open Access Journals (Sweden)

    Miha Mišič

    2003-06-01

    Full Text Available Kiscellian marine silt termed »sivica« is widely developed in Tertiary basins of Eastern Slovenia. Chemical composition is rather uniform and reflects the dominance of filosilicates (mainly illite/muscovite, chlorite and montmorillonite and carbonates. PAAS normalised REE and Y abundances are slightly depleted for La, Ce, Pr and Nd, very close to PAAS for Sm, Eu, Gd and Tb, and depleted for Y, Ho, Er, Tm, Yb and Lu.

  18. Quantitative mapping and statistical evaluation of fracture minerals in the granitic bedrock at Forsmark, Sweden

    Science.gov (United States)

    Löfgren, Martin; Sidborn, Magnus

    2016-10-01

    This article provides quantitative data on occurrences and amounts of fracture minerals that coat discrete fractures in granitic rock at the Forsmark site in Sweden. The data are useful for retardation modelling of radionuclide and other contaminants, and for groundwater composition calculations. In a unique campaign, 2071 open fractures in groundwater conducting rock have been mapped with respect to chlorite, calcite, and pyrite. In total 767 m of drill core has been studied from very shallow rock down to ~1000 m depth. The occurrences of fracture minerals, their thicknesses, and their fractions of surface coverage have been recorded for up to eight layers for each fracture. Detection limits are, for each layer, 0.1 mm for the thickness and 1 % for the surface coverage, except for pyrite crystals where surface coverages down to 0.01 % are detectable. The abundance of data has permitted statistical treatment, using parametric and non-parametric methods. Parametric fittings have been made to log-normal, truncated log-normal, and beta distributions. Chlorite, calcite, and pyrite were found in 57 %, 52 %, and 10 % of all mapped fractures, respectively. The fracture mineral thickness was 0.1 mm for calcite, 0.2 mm for chlorite, and 2 μm for pyrite, as averaged over the fracture surface area. For 50 % and 99 % of all fractures the total fracture coating thickness was less than 0.1 mm and 1 mm, respectively, which is important for diffusion resistance estimates. Average surface coverages were 18 % for calcite, 38 % for chlorite, and 0.5 % for pyrite. These data may be used for calculating the reaction capacity of flow paths.

  19. Abiotic CO2 reduction during geologic carbon sequestration facilitated by Fe(II)-bearing minerals

    Science.gov (United States)

    Nielsen, L. C.; Maher, K.; Bird, D. K.; Brown, G. E.; Thomas, B.; Johnson, N. C.; Rosenbauer, R. J.

    2012-12-01

    Redox reactions involving subsurface minerals and fluids and can lead to the abiotic generation of hydrocarbons from CO2 under certain conditions. Depleted oil reservoirs and saline aquifers targeted for geologic carbon sequestration (GCS) can contain significant quantities of minerals such as ferrous chlorite, which could facilitate the abiotic reduction of carbon dioxide to n-carboxylic acids, hydrocarbons, and amorphous carbon (C0). If such reactions occur, the injection of supercritical CO2 (scCO2) could significantly alter the oxidation state of the reservoir and cause extensive reorganization of the stable mineral assemblage via dissolution and reprecipitation reactions. Naturally occurring iron oxide minerals such as magnetite are known to catalyze CO2 reduction, resulting in the synthesis of organic compounds. Magnetite is thermodynamically stable in Fe(II) chlorite-bearing mineral assemblages typical of some reservoir formations. Thermodynamic calculations demonstrate that GCS reservoirs buffered by the chlorite-kaolinite-carbonate(siderite/magnesite)-quartz assemblage favor the reduction of CO2 to n-carboxylic acids, hydrocarbons, and C0, although the extent of abiotic CO2 reduction may be kinetically limited. To investigate the rates of abiotic CO2 reduction in the presence of magnetite, we performed batch abiotic CO2 reduction experiments using a Dickson-type rocking hydrothermal apparatus at temperatures (373 K) and pressures (100 bar) within the range of conditions relevant to GCS. Blank experiments containing CO2 and H2 were used to rule out the possibility of catalytic activity of the experimental apparatus. Reaction of brine-suspended magnetite nanoparticles with scCO2 at H2 partial pressures typical of reservoir rocks - up to 100 and 0.1 bars respectively - was used to investigate the kinetics of magnetite-catalyzed abiotic CO2 reduction. Later experiments introducing ferrous chlorite (ripidolite) were carried out to determine the potential for

  20. Study of corrosion resistance of chromium-nickel steel in calcium-hypochlorite solution part 2: Steels Č 4574 and Č 4583

    Directory of Open Access Journals (Sweden)

    Tošković D.

    2003-01-01

    Full Text Available This paper shows the results of investigations of corrosion resistance of different samples of chromium-nickel steels Č 4574 and Č 4583 in calcium-hypochlorite solution, by potentiodynamic method. The paper presents continuation of investigations on steels URANUS B6 and Č 4578 published in reference [1]. In this paper comparison of the obtained results is carried out, too, in order to detect steel, which quality is the best choice for calcium hypo chlorite solution requirements.

  1. Disinfection aboard cruise liners and naval units: formation of disinfection by-products using chlorine dioxide in different qualities of drinking water.

    Science.gov (United States)

    Ufermann, Petra; Petersen, Hauke; Exner, Martin

    2011-12-01

    The world-wide deployment of cruise liners and naval units has caused an increased need for the disinfection of drinking water. The main cause for this is the unknown quality of drinking water in foreign harbours--besides the formation of bio-films due to the climatically disadvantageous conditions in the operational area. Water conduits on board are currently disinfected with calcium hypochlorite in case of microbiological contamination. Chemical and physical analyses after disinfection with calcium hypochlorite have shown that organic by-products consisting of trihalomethanes develop in considerable amounts during disinfection. Furthermore, the method is susceptible to handling errors and thus often leads to insufficient disinfection results. Hitherto, the use of other disinfection methods allowed by government regulations, especially chlorine dioxide, is not widely spread. Unlike disinfection with calcium hypochlorite, chlorine dioxide does not lead to the formation of trihalomethanes. Typical disinfection by-products (DBP) are the anions chlorite and chlorate, which are formed in oxidative processes. The formation conditions of these anions have not yet been elucidated. For this reason, the probability of the generation of inorganic by-products after disinfection with chlorine dioxide has been determined, and their occurrence in drinking water on board has been examined with respect to a possible correlation between water quality and the formation of chlorate and chlorite. Therefore, a chromatographic method was developed and validated in order to determine the periodical development of chlorate and chlorite from chorine dioxide in purified water at different pH-values as well as in actual drinking water samples from water conduits on board. The formation of the by-products chlorite and chlorate after disinfection with chlorine dioxide is influenced neither by pH-value nor by chemical properties of the disinfected water. Considering the examined conditions

  2. Clay mineralogy of the Boda Claystone Formation (Mecsek Mts., SW Hungary

    Directory of Open Access Journals (Sweden)

    Németh Tibor

    2016-04-01

    Full Text Available Boda Claystone Formation (BCF is the host rock of the planned site for high level nuclear waste repository inHungary. Samples representing the dominant rock types of BCF were studied: albitic claystone, claystone with high illite content, and analcime bearing claystone. Clay minerals in these three rock types were characterized by Xray powder diffraction (XRD, transmission electron microscopy (TEM and thermal analysis (DTA-TG, and the results were discussed from the point of view of the radionuclide sorption properties being studied in the future. Mineral compositions of bulk BCF samples vary in wide ranges. In the albitic sample, besides the dominant illite, few percent of chlorite represents the layer silicates in the clay fraction. Illite is the dominating phase in the illitic sample, with a few percent of chlorite. HRTEM study revealed that the thickness of illite particles rarely reaches 10 layers, usually are of 5-6 TOT layer thick. Illite crystals are generally thicker in the albitic sample than in the illitic one. The significant difference between the clay mineral characterisitics of the analcimous and the other two samples is that the former contains regularly interstratified chlorite/smectite beside the dominant illite.

  3. Germicidal persistence of teat dips by modified excised teat procedure.

    Science.gov (United States)

    Schmidt, A L; Oliver, S P; Fydenkevez, M E

    1985-01-01

    An excised teat protocol was modified to evaluate persistence of germicidal activity of teat dips over 8 h. Five teat dip formulations, iodophor (1%), chlorhexidine gluconate (.55%), linear dodecyl benzene sulfonic acid (1.94%), sodium chlorite-lactic acid in a water base, and sodium chlorite-lactic acid in a gel base were tested against Escherichia coli and Klebsiella oxytoca. Iodophor and chlorhexidine had high germicidal activity throughout 8 h, whereas dodecyl benzene sulfonic acid had little activity. Germicidal activity of both sodium chlorite-lactic acid teat dips was high initially but declined with time. The gel base dip, however, remained more germicidal than the water base dip. Results were similar for either organism for most teat dips. However, chlorhexidine was less effective and the gel base dip more effective against Klebsiella oxytoca than Escherichia coli. Standard errors often appeared higher for Klebsiella oxytoca than for Escherichia coli. These assays may prove useful for laboratory screening of teat dips to determine germicidal persistence over time. PMID:3884679

  4. SECONDARY MINERAL PARAGENESIS IN THE MAFIC EXTRUSIVE ROCKS FROM THE MT. MEDVEDNICA OPHIOLITE MÉLANGE (CROATIA

    Directory of Open Access Journals (Sweden)

    Damir Slovenec

    2012-12-01

    Full Text Available The samples of partly or completely altered basaltic extrusive rocks from Mt. Medvednica ophiolite mélange were analysed by the optical microscopy and by X-ray powder diffraction (XRD. The chemical composition of minerals from different paragenetic assembleges were determinated by electron probe microanalysis (EPMA and the measured microdomains were documented by back-scattered electrons (BSE imagery. The most widespread alteration processes that affected analysed rocks are albitization, chloritization, epidotization, prehnitization, pumpellyitization, zeolitization and titanitization. Subordinate processes that include formation of limonite, calcite, zoisite, siderite, hematite, Mn-oxydes, pyrite and SiO2-phases were not constrained in this paper. Albitization is fairly dominant alteration process in all rock and its progradation throughout a plagioclase grain is clearly documented by BSE microphotographs and microprobe chemical analysis. Prehnite and laumontite are sporadic alteration products of plagioclases. The chemical components released during the alterations of plagioclases and/or clinopyroxenes along with components from circulating and percolating heated see water and fluids enable formation of chlorites, epidote and pumpellyite. Chlorites and pumpellyite formed also by devitrification of volcanic glass in vitric rim of pillow lavas. Small patches of leucoxene, that is abundant in all samples, represent dense aggregates of titanite nanocrystals replacing ilmenite and/or Ti-magnetite. Epidote-bearing paragenesis in the analyzed rocks record comparatively the highest alterations grade that correspond to the middle grade of greenschist facies metamorphism typical of upper sequence of a see floor crust (the paper is published in Croatian.

  5. Carboxymethylcellulose Obtained by Ethanol/Water Organosolv Process Under Acid Conditions

    Science.gov (United States)

    Ruzene, Denise S.; Gonçalves, Adilson R.; Teixeira, José A.; Pessoa de Amorim, Maria T.

    Sugar cane bagasse pulps were obtained by ethanol/water organosolv process under acid and alkaline conditions. The best condition of acid pulping for the sugarcane bagasse was 0.02 mol/L sulfuric acid at 160°C, for 1h, whereas the best condition for alkaline pulping was 5% sodium hydroxide (base pulp) at 160°C, for 3h. For the residual lignin removal, the acid and alkaline pulps were submitted to a chemical bleaching using sodium chlorite. Pulps under acid and alkaline conditions bleached with sodium chlorite presented viscosities of 3.6 and 7.8 mPas, respectively, and μ-kappa numbers of 1.1 and 2.4, respectively. The pulp under acid condition, bleached with sodium chlorite was used to obtain carboxymethylcellulose (CMC). CMC yield was 35% (pulp based), showing mass gain after the carboxymethylation reaction corresponding to 23.6% of substitution or 0.70 groups-CH2COONa per unit of glucose residue. The infrared spectra showed the CMC characteristic bands and by the infrared technique it was possible to obtain a substitution degree (0.63), similar to the substitution degree calculated by mass gain (0.70).

  6. Clay mineral records of East Asian monsoon evolution during late Quaternary in the southern South China Sea

    Institute of Scientific and Technical Information of China (English)

    LIU Zhifei; C. Colin; A. Trentesaux; D. Blamart

    2005-01-01

    High-resolution clay mineral records combined with oxygen isotopic stratigraphy over the past 190 ka during late Quaternary from core MD01-2393 off the Mekong River in the southern South China Sea are reported to reconstruct a history of East Asian monsoon evolution.The dominating clay mineral components indicate a strong glacial-interglacial cyclicity, with high glacial illite, chlorite, and kaolinite contents and high interglacial smectites content. The provenance analysis indicates the direct input of clay minerals via the Mekong River drainage basin.Illite and chlorite derived mainly from the upper reach of the Mekong River, where physical erosion of meta-sedimentary rocks is dominant. Kaolinite derived mainly from active erosion of inhered clays from reworked sediments in the middle reaches. Smectites originated mainly through bisiallitic soils in the middle to lower reaches of the Mekong River. The smectites/(illite+chlorite)and smectites/kaolinite ratios are determined as mineralogical indicators of East Asian monsoon variations. Relatively high ratios occur during interglacials and indicate strengthened summer-monsoon rainfall and weakened winter-monsoon winds; relatively lower ratios happened in glacials, indicating intensified winter monsoon and weakened summer monsoon. The evolution of the summer and winter monsoons provides an almost linear response to the summer insolation of the Northern Hemisphere, implying an astronomical forcing of the East Asian monsoon evolution.

  7. Biotite weathering in podzolic soil under conditions of a model field experiment

    Science.gov (United States)

    Sokolova, T. A.; Tolpeshta, I. I.; Topunova, I. V.

    2010-10-01

    The biotite changes in the 1-5 μm fraction after its occurrence in the F, H, AE, and E horizons of a pale-podzolic soil for five years under conditions of a model field experiment were assessed by X-ray diffraction analysis. It was found that the main changes of the biotite in all the horizons included the degradational transformation of its crystal lattice to interstratified mica-vermiculite structures and vermiculite. The intensity of this process gradually decreased from the F horizon down the profile in parallel with the decrease in the amount of roots and the abundance and activity of microbiota. Chloritized structures were present among the products of the biotite weathering in the H, AE, and E horizons; the degree of chloritization gradually increased from the H horizon to the E horizon. The main identified products of the biotite weathering in the AE and E horizons formed during the 5 years of the model experiment were identified in the clay and fine-silt fractions from these horizons of the native pale-podzolic soils. Therefore, the vermiculite, soil chlorite, and mixed-layer illite-vermiculite minerals in the soils studied could be considered as products of the recent soil functioning. The obtained results and literature data showed that the weathering of biotite resulted in the formation of K- and Al-buffer systems.

  8. Nature of uranium mineralization and associated wall rock alteration in the White's East area of the Embayment, Rum Jungle, Northern Territory

    International Nuclear Information System (INIS)

    The uranium mineralisation in the White's East area of The Embayment is hosted by Lower Proterozoic schists of the Masson formation which have undergone polyphase deformation and upper greenschist metamorphism. Significant mineralisation is also present in apatite rocks. The ore zones occur near an unconformity with overlying Middle Proterozoic sandstone and breccia conglomerate. Kink breccias and fracture systems related to post Middle Proterozoic reverse faults are the controls for mineralising fluid migration. Pitchblende is the main uranium mineral and it occurs as fine disseminated grains, fibrous webs, clusters composed of botryoidal aggregates and locally as veins. Two generations of uranium mineralisation are present. The first generation (pitchblende I) occurs as fine grained inclusions within chlorite II, and the second (pitchblende II) as hydraulic fracture networks and massive veins intimately associated with sericite-hematite-chlorite III. Two hydrothermal alteration phases have affected both Lower Proterozoic and Middle Proterozoic sequences. The most extensive alteration mineral is chlorite, of which a number of varieties has been identified

  9. Comparative study of microfacies variation in two samples from the Chittenango member, Marcellus shale subgroup, western New York state, USA

    Energy Technology Data Exchange (ETDEWEB)

    Balulla, Shama, E-mail: shamamohammed77@outlook.com; Padmanabhan, E., E-mail: eswaran-padmanabhan@petronas.com.my [Department of Geoscience, Faculty of Geosciencs and Petroleum Engineering Universiti Teknologi PETRONAS, Tronoh (Malaysia); Over, Jeffrey, E-mail: over@geneseo.edu [Department of geological sciences, Geneseo, NY (United States)

    2015-07-22

    This study demonstrates the significant lithologic variations that occur within the two shale samples from the Chittenango member of the Marcellus shale formation from western New York State in terms of mineralogical composition, type of lamination, pyrite occurrences and fossil content using thin section detailed description and field emission Scanning electron microscope (FESEM) with energy dispersive X-Ray Spectrum (EDX). This study is classified samples as laminated clayshale and fossiliferous carbonaceous shale. The most important detrital constituents of these shales are the clay mineral illite and chlorite, quartz, organic matter, carbonate mineral, and pyrite. The laminated clayshale has a lower amount of quartz and carbonate minerals than fossiliferous carbonaceous shale while it has a higher amount of clay minerals (chlorite and illite) and organic matter. FESEM analysis confirms the presence of chlorite and illite. The fossil content in the laminated clayshale is much lower than the fossiliferous carbonaceous shale. This can provide greater insights about variations in the depositional and environmental factors that influenced its deposition. This result can be compiled with the sufficient data to be helpful for designing the horizontal wells and placement of hydraulic fracturing in shale gas exploration and production.

  10. Spectral properties and ASTER-based alteration mapping of Masahim volcano facies, SE Iran

    Science.gov (United States)

    Tayebi, Mohammad H.; Tangestani, Majid H.; Vincent, Robert K.; Neal, Devin

    2014-10-01

    This study applies Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and the Mixture Tuned Matched Filtering (MTMF) algorithm to map the sub-pixel distribution of alteration minerals associated with the Masahim volcano, SE Iran for understanding the spatial relationship between alteration minerals and volcano facies. Investigations of the alteration mineralogy were conducted using field-spectroscopy, X-ray diffraction (XRD) analysis and ASTER Short Wave Infrared (SWIR) spectral data. In order to spectrally characterize the stratovolcano deposits, lithological units and alteration minerals, the volcano was divided into three facies: the Central, Proximal, and Medial-distal facies. The reflectance spectra of rock samples show absorption features of a number of minerals including white mica, kaolinite, montmorillonite, illite, goethite, hematite, jarosite, opal, and chlorite. The end-members of key alteration minerals including sericite (phyllic zone), kaolinite (argillic zone) and chlorite (propylitic zone) were extracted from imagery using the Pixel Purity Index (PPI) method and were used to map alteration minerals. Accuracy assessment through field observations was used to verify the fraction maps. The results showed that most prominent altered rocks situated at the central facies of volcano. The alteration minerals were discriminated with the coefficient of determination (R2) of 0.74, 0.81, and 0.68 for kaolinite, sericite, and chlorite, respectively. The results of this study have the potential to refine the map of alteration zones in the Masahim volcano.

  11. Formation mechanism of ferromagnetic minerals in loess of China: TEM investigation

    Institute of Scientific and Technical Information of China (English)

    CHEN Tianhu; XU Huifang; JI Junfeng; CHEN Jun; CHEN Yang

    2003-01-01

    The results of TEM investigation indicate that magnetite and maghemite are the major ferromagnetic minerals in loess-paleosol sequences. Primary magnetite has the similar morphology and surface characteristics as eolian detrital particles. The magnetite can be classified into two categories, high-titanium and low-titanium, which may be the indicators of magmatic rocks and metamorphic rocks, respectively. TEM investigation at nanometer scale shows that primary detrital magnetite of micron scale had been partially weathered to maghemite of 5~20 nanometer during the pedogenic process, which maintain the pseudomorphism of the aeolian debris. Some chlorite particles were also weathered to nanometer scale magnetite or maghemite in the pedogenic process. So weathering of the two minerals leads to formation of superparamagnetism, which may be the important mechanism of magnetic-susceptibility increase in paleosols. The magnetite or maghemite resulting from the weathering of chlorite contains a small amount of P and S, which is the signal of microbe-mineral interaction, and indicates that microbes may play a certain role in chlorite weathering and formation of superparamagnetic particles.

  12. Formation Rule of Chlorine Dioxide Disinfection By-products%二氧化氯消毒副产物的生成规律研究

    Institute of Scientific and Technical Information of China (English)

    张盛军; 张大钰; 董燕; 王永芳

    2013-01-01

    According to chlorite excessive phenomenon in chlorine dioxide sterilization of drinking water, Xiaoqinghe River and Darning Lake water were selected to study the relationship between chlorine dioxide consumption and chlorite production in the disinfection process. The removal of COD by chlorine dioxide was assessed. The results showed that chlorite production was positively correlated with chlorine dioxide consumption, and had no direct relation with chlorine dioxide dosage and COD concentration in water.%针对二氧化氯在饮用水消毒过程中出现的副产物亚氯酸盐超标现象,以小清河水和大明湖水为处理对象,研究了在消毒过程中二氧化氯的消耗量与亚氯酸盐的产生量之间的关系,同时测定了二氧化氯对COD的去除情况.结果表明,副产物亚氯酸盐的产生量与二氧化氯的消耗量呈正相关关系,而与二氧化氯的投加量及水体中的COD浓度没有直接关系.

  13. Equilibrium and kinetics in metamorphism of pelites in the Nelson aureole, British Columbia

    Science.gov (United States)

    Pattison, D. R. M.

    2009-04-01

    The distribution of metapelitic mineral assemblages in the Nelson aureole, British Columbia, generally conforms to what is predicted from phase equilibria. However, in detail, the mineral textures, mineral compositions and zoning, and sequence and spacing of isograds do not. Two of the main disequilibrium features in the aureole are: (1) delay in the onset and progress of several reactions, ie, thermal overstepping; and (2) unreactivity of staurolite and especially garnet porphyroblasts when they are reactants in higher grade reactions. The thermal overstepping is ascribed primarily to difficulty of nucleation of the product porphyroblasts and sluggishness of dissolution of reactant porphyroblasts required for product mineral growth. The extent to which these barriers to nucleation and growth delay the onset of reaction is related to the reaction affinity of each reaction, which for thermally activated reactions is, in turn, related to the entropy change of the reaction. For a given overstep in temperature, reactions that release large quatities of H2O, such as chlorite-consuming reactions, have a high reaction affinity compared to those which release little or no H2O, such as the chlorite-free staurolite-consuming reaction. Thermal overstepping is consequently expected to be less for the former than for the latter, as was observed in the aureole where ca. 30 °C overstepping was required for garnet growth from a muscovite+chlorite-bearing precursor and ca. 70 °C overstepping was required for growth of Al2SiO5 from a staurolite-bearing, chlorite-free precursor. In all cases reaction progress was strongly influenced by presence or absence of fluid, with fluid presence dramatically lowering kinetic barriers to nucleation and growth, and therefore thermal overstepping. Textural features of rocks from the nearly coincident garnet, staurolite and andalusite isograds are suggestive of a fluid-catalyzed ‘cascade effect' in which reaction took place rapidly and several

  14. Enhanced chlorine dioxide decay in the presence of metal oxides: Relevance to drinking water distribution systems

    KAUST Repository

    Liu, Chao

    2013-07-19

    Chlorine dioxide (ClO2) decay in the presence of typical metal oxides occurring in distribution systems was investigated. Metal oxides generally enhanced ClO2 decay in a second-order process via three pathways: (1) catalytic disproportionation with equimolar formation of chlorite and chlorate, (2) reaction to chlorite and oxygen, and (3) oxidation of a metal in a reduced form (e.g., cuprous oxide) to a higher oxidation state. Cupric oxide (CuO) and nickel oxide (NiO) showed significantly stronger abilities than goethite (α-FeOOH) to catalyze the ClO2 disproportionation (pathway 1), which predominated at higher initial ClO2 concentrations (56-81 μM). At lower initial ClO2 concentrations (13-31 μM), pathway 2 also contributed. The CuO-enhanced ClO2 decay is a base-assisted reaction with a third-order rate constant of 1.5 × 10 6 M-2 s-1 in the presence of 0.1 g L -1 CuO at 21 ± 1 C, which is 4-5 orders of magnitude higher than in the absence of CuO. The presence of natural organic matter (NOM) significantly enhanced the formation of chlorite and decreased the ClO 2 disproportionation in the CuO-ClO2 system, probably because of a higher reactivity of CuO-activated ClO2 with NOM. Furthermore, a kinetic model was developed to simulate CuO-enhanced ClO 2 decay at various pH values. Model simulations that agree well with the experimental data include a pre-equilibrium step with the rapid formation of a complex, namely, CuO-activated Cl2O4. The reaction of this complex with OH- is the rate-limiting and pH-dependent step for the overall reaction, producing chlorite and an intermediate that further forms chlorate and oxygen in parallel. These novel findings suggest that the possible ClO2 loss and the formation of chlorite/chlorate should be carefully considered in drinking water distribution systems containing copper pipes. © 2013 American Chemical Society.

  15. The Geology and Petrography of Yücebelen and Surrounding Area, Torul-Gümüşhane

    Science.gov (United States)

    Doǧacan, Özcan; Özpınar, Yahya

    2013-04-01

    The study area is located in the tectono-stratigraphic zone named "Eastern Pontide Zone" from the northeastern part of Turkey. Eastern Pontides were formed by the subduction of Tethys Ocean under the Eurasian plate, during the Early Cretaceous - Late Eocene. Eastern Pontide orogenic zone can be divided in two tectono-stratigraphic subgroups as the northern and southern zones. The study area is located very close to border of these two subgroups but located in northern zone. In this project, the first geological map of the study area at the scale 1:5000 was made. Subsequently, detailed geological maps at the scale 1:2000 were made for the areas rich in ores. In the study area, Upper Cretaceous volcanic rocks consisting of basalts and basaltic andesites take place at the bottom of the rock sequence. Basalts and basaltic andesites with hyaloophitic, vitrophiric and microporphyric texture comprise plagioclase +pyroxene +chlorite +calcite ±epidote ±chalcedony ±opaque minerals. They are overlain by concordant pyroclastic and dacitic-rhyodacitic rocks. Quarts + K-feldispar ±plagioclase? ±biotite ±chlorite ±calcite ±chalcedony minerals are determined as a result of microscope investigation on samples taken from these rocks. These rocks are overlain by sedimentary rocks intercalated with pyroclastic rocks. All those units mentioned above, were intruded by granitoids of supposed Upper Cretaceous-Eocene age. Granitoids that crop out in the area were classified in terms of Q-ANOR parameters as granodiorites (Adile Hamlet occurrence - investigated in detail), diorites (Tuzlak Hill occurrence- eastern-part of study area) and quartz monzodiorites (İstavroma Hill occurrence- northern part of study area). Adile Hamlet granodiorites comprise plagioclase +pyroxene +chlorite +calcite ±quarts ±epidote +opaque minerals. A sequence of quarts +orthoclase +plagioclase ±chlorite ±epidote ±calcite ±opaque minerals have been determined after investigation of the rock samples

  16. Hydrothermal alteration and magnetic properties of rocks in the Carolina de Michilla stratabound copper district, northern Chile

    Science.gov (United States)

    Townley, Brian; Roperch, Pierrick; Oliveros, Verónica; Tassara, Andres; Arriagada, César

    2007-10-01

    In the Carolina de Michilla district, northern Chile, stratabound copper mineralization is hosted by Jurassic volcanic rocks along the trace of the Atacama fault system. In this study, we present the overall effects of hydrothermal alteration on the magnetic properties of rocks in this district. Two types of metasomatic alteration associations occur, one of regional extent and the other of local hydrothermal alteration associated with copper mineralization (e.g., Lince Estefanía Susana). Regional alteration is interpreted as a low-grade “propylitic association” characterized by an epidote chlorite smectite titanite albite quartz calcite association. The local hydrothermal alteration is characterized broadly by a quartz albite epidote chlorite calcite mineral assemblage. The most pervasive alteration mineral is albite, followed by epidote and, locally, actinolite. These minerals contrast sharply against host rock minerals such as chlorite, calcite, zeolite, prehnite, and pumpellyite, but alteration is constrained to mineralized bodies as narrow and low contrast alteration halos that go outwards from actinolite albite to epidote albite, to epidote chlorite, and finally to chlorite. Hydrothermal alteration minerals, compared to regional alteration minerals, show iron-rich epidotes, a lower chlorite content of the chlorite smectite series, and a nearly total albite replacement of plagioclase in the mineralized zones. Opaque minerals associated with regional alteration are magnetite and maghemite, and those associated to hydrothermal alteration are magnetite, hematite, and copper sulphides. We present paleomagnetic results from nine sites in the Michilla district and from drill cores from two mines. Local effects of hydrothermal alteration on the original magnetic mineralogy indicate similar characteristics and mineralogy, except for an increase of hematite that is spatially associated with the Cu sulphide breccias with low magnetic susceptibilities. Results

  17. Mobility of gold during metamorphism of the Dalradian in Scotland

    Science.gov (United States)

    Pitcairn, I. K.; Skelton, A. D. L.; Wohlgemuth-Ueberwasser, C. C.

    2015-09-01

    Mobility of Au and related metals during metamorphism has been suggested to be the source of metals enriched in orogenic Au deposits. This study investigates the mobility of Au, As, and Sb during metamorphism of the Dalradian metasedimentary rocks of Scotland. The metamorphic processes in the Dalradian of Scotland are extremely well studied, and the terrane is an ideal area to investigate mobility of these metals. Our results show that of the 25 major and trace elements analysed, only Au, As, Sb, S and volatile contents as shown by loss on ignition (LOI) values show systematic variation with the metamorphic grade of the samples. Average Au concentrations decrease from 1.1 ± 0.55 ppb and 0.72 ± 0.34 ppb in chlorite and biotite zone rocks down to 0.4 ± 0.22 ppb and 0.34 ± 0.13 ppb in kyanite and sillimanite zone rocks. Average As concentrations decrease from 4.8 ppm (range 0.5 to 17.8 ppm) and 1.96 ± 1.9 ppm in chlorite and biotite zone rocks down to 0.24 ± 0.15 ppm and 0.2 ± 0.12 ppm in kyanite and sillimanite zone rocks. Average Sb concentrations decrease from 0.18 ± 0.15 ppm and 0.11 ± 0.10 ppm in chlorite and biotite zone rocks down to 0.04 ± 0.02 ppm in both kyanite and sillimanite zone rocks. Sulphur and LOI concentrations also show significant decreases. Mass balance calculations indicate that compared to chlorite and biotite zone samples, sillimanite zone samples have an average mass loss of 62 ± 14%, 94 ± 4% and 74 ± 14% for Au, As, and Sb respectively. Every 1 km3 of chlorite-biotite zone mixed psammitic-pelitic protolith rock that is metamorphosed to sillimanite zone conditions would release 1.5 t Au, 8613 t As, 270 t Sb, and 1.02 Mt S. The mobility of these elements is strongly controlled by the paragenesis of sulphide minerals. Pyrite, sphalerite, galena and cobaltite (as well as gersdorffite) decrease in abundance with increasing metamorphic grade in the Dalradian metasedimentary rocks. A critical aspect of the sulphide paragenesis is the

  18. Deposition of talc - kerolite-smectite - smectite at seafloor hydrothermal vent fields: Evidence from mineralogical, geochemical and oxygen isotope studies

    Science.gov (United States)

    Dekov, V.M.; Cuadros, J.; Shanks, Wayne C.; Koski, R.A.

    2008-01-01

    Talc, kerolite-smectite, smectite, chlorite-smectite and chlorite samples from sediments, chimneys and massive sulfides from six seafloor hydrothermal areas have been analyzed for mineralogy, chemistry and oxygen isotopes. Samples are from both peridotite- and basalt-hosted hydrothermal systems, and basaltic systems include sediment-free and sediment-covered sites. Mg-phyllosilicates at seafloor hydrothermal sites have previously been described as talc, stevensite or saponite. In contrast, new data show tri-octahedral Mg-phyllosilicates ranging from pure talc and Fe-rich talc, through kerolite-rich kerolite-smectite to smectite-rich kerolite-smectite and tri-octahedral smectite. The most common occurrence is mixed-layer kerolite-smectite, which shows an almost complete interstratification series with 5 to 85% smectitic layers. The smectite interstratified with kerolite is mostly tri-octahedral. The degree of crystal perfection of the clay sequence decreases generally from talc to kerolite-smectite with lower crystalline perfection as the proportion of smectite layers in kerolite-smectite increases. Our studies do not support any dependence of the precipitated minerals on the type/subtype of hydrothermal system. Oxygen isotope geothermometry demonstrates that talc and kerolite-smectite precipitated in chimneys, massive sulfide mounds, at the sediment surface and in open cracks in the sediment near seafloor are high-temperature (> 250????C) phases that are most probably the result of focused fluid discharge. The other end-member of this tri-octahedral Mg-phyllosilicate sequence, smectite, is a moderate-temperature (200-250????C) phase forming deep within the sediment (??? 0.8??m). Chlorite and chlorite-smectite, which constitute the alteration sediment matrix around the hydrothermal mounds, are lower-temperature (150-200????C) phases produced by diffuse fluid discharge through the sediment around the hydrothermal conduits. In addition to temperature, other two

  19. Steatite and schist as contenders for the Global Heritage Stone Resource due to their importance in Brazil's natural stone built heritage

    Science.gov (United States)

    Gilberto Costa, Antônio

    2013-04-01

    In Brazil, European natural stones, such as marble and limestone, were used as building material at historically important buildings and monuments, mainly in coastal cities, as well as in contemporary urban centers. However, in the country's central region, these Italian and Portuguese marbles and limestones were scarcely used. Instead, they were substituted for soapstone and several types of schist. As of 1755, the former was employed because of the ease with which it can be worked, essentially in the sculptural art and in the production of ornamental elements. Characterized by the presence of talc, steatite can feature other minerals such as serpentine, chlorite, carbonate, amphiboles, oxides like hematite and magnetite, and sulfites like pyrite, all in broadly variable amounts, which can result in modification of its technological properties (Volumetric Weight, Porosity, Water Absorption, Uniaxial Compression, Abrasion Resistance, Thermal Expansion etc.). In such rocks, talc content will be a decisive factor in their coloration. The higher its talc content is the clearer and softer the stone type will be, which ends up being known as talc stone. In such cases, the rock can display different hues of green, blue and gray. When compared to other rocks, texture patterns containing talc crystals, chlorite and carbonate contribute to low absorption and porosity for steatites. Schists were equally used at historical buildings in the Brazilian inland, especially in constructions in Minas Gerais towns, both in the production of structural elements such as bases, corners, pillars and foundations and in the creation of ornaments. Featuring different compositions, such rocks - which almost always occur interlayered with other ones such as quartzite - display coloration ranging from hues of gray to green to blue. They can be quartz-sericite-albite-chlorite schists featuring great or no amounts of carbonate, magnetite, epidote and tourmaline, sometimes with garnet, such as in

  20. The Damage and Geochemical Signature of a Crustal Scale Strike-Slip Fault Zone

    Science.gov (United States)

    Gomila, R.; Mitchell, T. M.; Arancibia, G.; Jensen Siles, E.; Rempe, M.; Cembrano, J. M.; Faulkner, D. R.

    2013-12-01

    Fluid-flow migration in the upper crust is strongly controlled by fracture network permeability and connectivity within fault zones, which can lead to fluid-rock chemical interaction represented as mineral precipitation in mesh veins and/or mineralogical changes (alteration) of the host rock. While the dimensions of fault damage zones defined by fracture intensity is beginning to be better understood, how such dimensions compare to the size of alteration zones is less well known. Here, we show quantitative structural and chemical analyses as a function of distance from a crustal-scale strike-slip fault in the Atacama Fault System, Northern Chile, to compare fault damage zone characteristics with its geochemical signature. The Jorgillo Fault (JF) is a ca. 18 km long NNW striking strike-slip fault cutting Mesozoic rocks with sinistral displacement of ca. 4 km. In the study area, the JF cuts through orthogranulitic and gabbroic rocks at the west (JFW) and the east side (JFE), respectively. A 200 m fault perpendicular transect was mapped and sampled for structural and XRF analyses of the core, damage zone and protolith. The core zone consists of a ca. 1 m wide cataclasite zone bounded by two fault gouge zones ca. 40 cm. The damage zone width defined by fracture density is ca. 50 m wide each side of the core. The damage zone in JFW is characterized by NW-striking subvertical 2 cm wide cataclastic rocks and NE-striking milimetric open fractures. In JFE, 1-20 mm wide chlorite, quartz-epidote and quartz-calcite veins, cut the gabbro. Microfracture analysis in JFW reveal mm-wide cataclasitic/ultracataclasitic bands with clasts of protolith and chlorite orientated subparallel to the JF in the matrix, calcite veins in a T-fractures orientation, and minor polidirectional chlorite veins. In JFE, chlorite filled conjugate fractures with syntaxial growth textures and evidence for dilational fracturing processes are seen. Closest to the core, calcite veins crosscut chlorite veins

  1. Investigation on type and origin of iron mineralization at Mesgar occurrence, south of Zanjan, using petrological, mineralogical and geochemical data

    Directory of Open Access Journals (Sweden)

    Mohammad Ebrahimi

    2015-04-01

    150 m in length and average 1.5 m in width, reaching a maximum of 3 m. Two stages of mineralization identified at Mesgar. Stage-1 mineralization formed before the hydrothermal brecciation events. This stage is characterized by disseminated fine-grained hematite in the andesitic basalt lavas. Clasts of stage-1 mineralization have been recognized in the hydrothermal breccias of stage-2. Stage-2 is represented by quartz, hematite and chlorite veins and breccias cement. This stage contains abundant hematite, together with minor magnetite and chalcopyrite. The hydrothermal alteration assemblages at Mesgar grade from proximal quartz and chlorite to distal sericite and chlorite-calcite. The quartz and chlorite alteration types are spatially and temporally closely associated with iron mineralization. The sericite and chlorite-calcite alterations mark the outer limit of the hydrothermal system. Supergene alteration (kaolinite is commonly focused along joints and fractures. The ore minerals at Mesgar formed as vein and hydrothermal breccia cements, and show vein-veinlet, massive, brecciated, clastic and disseminated textures. Hematite is the main ore which is accompanied by minor magnetite and chalcopyrite. Goethite is a supergene mineral. Quartz and chlorite are present in the gangue minerals that represent vein-veinlet, vug infill, colloform, cockade and crustiform textures. The Mesgar volcanic host rocks are characterized by LILE and LREE enrichment coupled with HFSE depletion. They have positive U, Th and Pb and negative Ba, Nb, P and Ti anomalies. Our geochemical data indicate a calc-alkaline affinity for the volcanic rocks (Kuster and Harms, 1998; Ulmer, 2001, and suggest that they originated from mantle melts contaminated by the crustal materials (Chappell and White, 1974; Miyashiro, 1977; Harris et al., 1986. The ore zones show lower concentrations of REE, except Ce, relative to fresh volcanic host rocks. LREE are more depleted than HREE. These signatures indicate high

  2. Environment of ore deposition in the Creede mining district, San Juan Mountains, Colorado; Part IV, source of fluids, from oxygen, hydrogen, and carbon isotope studies

    Science.gov (United States)

    Bethke, P.M.; Rye, R.O.

    1979-01-01

    The hydrogen isotopic composition of fluids responsible for formation of the near-surface silver-base metal vein deposits at Creede was measured by direct analysis of inclusion fluids in sphalerite, quartz, and rhodochrosite and was estimated from analyses of illite and chlorite. The oxygen isotopic composition was determined directly on inclusion fluids in sphalerite and was estimated from analyses of quartz, illite, rhodochrosite, siderite, and adularia. The carbon isotopic composition was estimated from analyses of rhodochrosite and siderite. The ranges in isotopic composition for water and CO2 in the fluids associated with the formation of each of the minerals is given below (number of determinations given in parentheses):Mineral delta D (sub H2) O ppm delta 18 O (sub H2) O ppm delta 13 C (sub CO2) ppmSphalerite -81 to -54 (4) -10.1 to -4.5 (4)Quartz -97 to -86 (4) -5.9 to 1.8 (18)Illite -62 to -50 (8) -1.6 to 1.2(7)Chlorite -64 to -55 (10) -2.2 to 0.8 (10)Adularia 4.2 (1)Rhodochrosite -82 to -78 (2) 4.2 to 9.4 (9) -5.7 to -4.2 (9)Siderite 4.9 to 9.9 (6) -6.9 to -2.7 (6)The delta D (sub H2) O and delta 18 O (sub H2) O values of fluids associated with the formation of sphalerite, quartz, illite/chlorite, and carbonate minerals differ substantially from one another, and these differences appear to have been maintained throughout the depositional history, regardless of the positions of the minerals in the paragenetic sequence.The data suggest that waters from three coexisting reservoirs fed the vein system alternately and episodically during vein formation, and apparently there was little mixing of the fluids from the different reservoirs. The hydrogen, oxygen, and carbon isotope data suggest that the carbonate waters were deep seated, probably dominantly magmatic, in origin. The sphalerite and illite/chlorite waters must have been dominantly meteoric in origin and substantially oxygen shifted by exchange with the volcanic country rocks. The quartz waters were

  3. Mineralogía y génesis de las arcillas del Campo de Gibraltar. III. Unidad de Algeciras

    Directory of Open Access Journals (Sweden)

    Ruiz Cruz, M. D.

    1988-08-01

    Full Text Available The study of Algelciras unit, iniciated with the seríes of Rinconcillo (Ruiz Cruz et al., 1987, is now completed. The mineralogical results of the Punta Tarifa series are analyzed, and are compared with the former studies, and, also conclusions relative to the Algeciras unit are exposed. The Punta Tarifa series is characterized by the high content of illite-rich interestratified clay minerals (illite-vermiculite; illite-smectite, illite -vermiculite-smectite, illite-chlorite and the constant presence of chlorites of variable genesis. The differences between these series come from the different content in clay minerals, specially, smectite, palygorskite, kaolinite and chlorite. Differences are related with chemical characteristics of depositional and/or diagenetic environment and, also, with different alteration degree of detrític minerals.Este trabajo completa el estudio de la unidad de Algeciras, iniciado anteriormente (Ruiz Cruz et al., 1987, con el estudio de la serie tipo El Rinconcillo. Se analizan los resultados obtenidos en la serie tipo Punta Tarifa, se comparan con los anteriores y se exponen las conclusiones relativas a la unidad de Algeciras. La serie tipo Punta Tarifa se caracteriza por el porcentaje alto de interestratificados I-V, I-E, I.V-E, CI-I, ricos en láminas de ilita, Y la presencia bastante constante de cloritas con orígenes diversos. Las diferencias entre las series tipo estudiadas vienen dadas especialmente por el diferente contenido en determinados minerales, especialmente esmectitas, paligorskita, caolinita y clorita, que es debido fundamentalmente a diferencias en el medio químico durante el depósito y la diagénesis y, en cierta medida, al diferente grado de alteración de los minerales detríticos.

  4. Fluid–rock interaction across the South Tibetan Detachment, Garhwal Himalaya (India): Mineralogical and geochemical evidences

    Indian Academy of Sciences (India)

    Anubhooti Saxena; Himanshu K Sachan; Pulok K Mukherjee; Dilip K Mukhopadhya

    2012-02-01

    The Malari Leucogranite in the Garhwal Himalaya is cut across by a continental-scale normal fault system called the South Tibetan Detachment (STD). A mineralogical, geochemical and fluid inclusion study of samples from the fault zone of the Malari Granite was performed to reveal the imprints of fluid–rock interaction. Fluid inclusion assemblages observed in the alteration zone indicate the presence of NaCl-dominated aqueous fluids with varied salinity of 6 –16 wt.% of NaCl equivalent. Mineralogical changes include the alteration of feldspar to muscovite and muscovite to chlorite. This alteration took place at temperatures of 275°–335°C and pressures between 1.9 and 4.2 kbars as revealed by the application of chlorite thermometry, fluid isochores, and presence of K-feldspar+muscovite+chlorite+quartz mineral assemblage. Geochemical mass-balance estimates predict 32% volume loss during alteration. An estimated fluid/rock ratio of 82 is based on loss of silica during alteration, and reveals presence of a moderately low amount of fluid at the time of faulting. Results of fluid inclusion and alteration mineralogy indicate that the Malari Leucogranites were exhumed due to normal faulting along the STD and erosion from mid-crustal levels. Most of the leucogranites in the Himalayas occur along the STD and possibly a regional-scale fluid flow all along the STD might have caused similar alteration of leucogranites along this tectonic break. Regional fluid flow was probably concentrated along the STD and channelized through mesoscopic fractures, microcracks and grain boundaries.

  5. Activity diagrams for calcium/hydrogen, sodium/hydrogen, and potassium/hydrogen, and H4SiO4 and their relation to reactions in systems containing radioactive waste forms, cement, and rock in the presence of water

    International Nuclear Information System (INIS)

    In order to identify reactions which can occur in systems containing nuclear waste forms, cement, and repository rock in the presence of water, activity diagrams were calculated from free energies for aluminosilicates and calcium silicates. Groundwater compositions from candidate repository sites in the Palo Duro Basin of Texas, the Delaware Basin of New Mexico, and the Nevada Test Site were plotted on these diagrams. Essentially all of these are shown to be in the calcium zeolite field as shown on the diagram for calcium in the absence of other cations. Chlorite is shown to be stable in this region at the Mg and pH level of the Ogallala if the chlorite is high in iron, and at the Mg and pH level of the Wolfcamp low- or high-Fe chlorites are stable. Potassium and sodium mineral relationships fall in two categories, dilute waters and saline waters. Boreholes at Yucca Flat and Mercury Valley at the Nevada Test Site, and shallow ground water from the Rolling Plains north and east of the Palo Duro Basin are in equilibrium with kaolinite. The brines from the Salado and Rustler formations are in equilibrium with kaolinite and possibly also with sodium-potassium zeolite and illite. Leachates of cement and water, and cement, waste, and water were plotted on the calcium silicate activity diagram. These solutions are in equilibrium with calcium silicate hydrate hydrolysis reactions, with grossular and possibly with Ca-zeolites. Among the calcium silicates, calcium-silicate-hydrate gel (C-S-H gel) and tobermorite are the most likely candidates, but the thermodynamic data are not adequate to distinguish all the possibilities. 37 references, 4 figures, 3 tables

  6. Change of iron species and iron solubility in Asian dust during the long-range transport from western China to Japan

    Directory of Open Access Journals (Sweden)

    Y. Takahashi

    2011-11-01

    Full Text Available In the North Pacific, transport and deposition of mineral dust from Asia appear to be one of major sources of iron which can regulate growth of phytoplankton in the ocean. In this process, it is essential to identify chemical species of iron contained in Asian dust, because bioavailability of iron in the ocean is strongly influenced by the solubility of iron, which in turn is dependent on iron species in the dust. Here, we report that clay minerals (illite and chlorite in the dusts near the source collected at Aksu (western China can be transformed into ferrihydrite by atmospheric chemical processes during their long-range transport to eastern China (Qingdao and Japan (Tsukuba based on the speciation by X-ray absorption fine structure (XAFS and other methods such as X-ray diffraction and chemical extraction. As a result, Fe molar ratio in Aksu (illite : chlorite : ferrihydrite = 70 : 25 : 5 was changed to that in Tsukuba (illite : chlorite : ferrihydrite = 65 : 10 : 25. Moreover, leaching experiments were conducted to study the change of iron solubility. It was found that the iron solubility for the dust in Tsukuba (soluble iron fraction: 11.8 % and 1.10 % for synthetic rain water and seawater, respectively was larger than that in Aksu (4.1 % and 0.28 %, respectively, showing that iron in the dust after the transport becomes more soluble possibly due to the formation of ferrihydrite in the atmosphere. Our findings suggested that secondary formation of ferrihydrite during the transport should be considered as one of important processes in evaluating the supply of soluble iron to seawater.

  7. Late Quaternary clay minerals off Middle Vietnam in the western South China Sea: Implications for source analysis and East Asian monsoon evolution

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    High-resolution clay mineral records combined with oxygen isotopic stratigraphy over the past 450 ka during late Quaternary from Core MD05-2901 off Middle Vietnam in the western South China Sea are reported to reconstruct a history of East Asian monsoon evolution.Variations in Illite,chlorite,and kaolinite contents indicate a strong glacial-interglacial cyclicity,while changes in smectite content present a higher frequency cyclicity.The provenance analysis indicates a mixture of individual clay minerals from various sources surrounding the South China Sea.Smectite derived mainly from the Sunda shelf and its major source area of the Indonesian islands.Illite and chlorite originated mainly from the Mekong and Red rivers.Kaolinite was provided mainly by the Pearl River.Spectral analysis of the kaolinite/(illite+chlorite) ratio displays a strong eccentricity period of 100 ka,implying the ice sheet-forced winter monsoon evolution; whereas higher frequency changes in the smectite content show an ice sheet-forced obliquity period of 41 ka,and precession periods of 23 and 19 ka and a semi-precession period of 13 ka as well,implying the tropical-forced summer monsoon evolution.The winter monsoon evolution is generally in coherence with the glacial-interglacial cyclicity,with intensified winter monsoon winds during glacials and weakened winter monsoon winds during interglacials; whereas the summer monsoon evolution provides an almost linear response to the summer insolation of low latitude in the Northern Hemisphere,with strengthened summer monsoon during higher insolation and weakened summer monsoon during lower insolation.The result suggests that the high-latitude ice sheet and low-latitude tropical factor could drive the late Quaternary evolution of East Asian winter and summer monsoons,respectively,implying their diplex and self-contained forcing mechanism.

  8. Lithologic characteristics and diagenesis of the Devonian Jauf sandstone at Ghawar Field, Eastern Saudi Arabia

    Energy Technology Data Exchange (ETDEWEB)

    Al Ramadan, K.A.; Hussain, M. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Earth Sciences; Imam, B. [Dhaka Univ. (Bangladesh). Dept. of Geology; Saner, S. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Research Inst.

    2004-12-01

    The Lower Devonian Jauf Formation in Saudi Arabia is an important hydrocarbon reservoir. However, in spite of its importance as a reservoir, published studies on the Jauf Formation more specifically on the reservoir quality (including diagenesis), are very few. This study, which is based on core samples from two wells in the Ghawar Field, northeastern Saudi Arabia, reports the lithologic and diagenetic characteristics of this reservoir. The Jauf reservoir is a fine to medium-grained, moderate to well-sorted quartz arenite. The diagenetic processes recognized include compaction, cementation (calcite, clay minerals, quartz overgrowths, and a minor amount of pyrite), and dissolution of the calcite cements and of feldspar grains. The widespread occurrences of early calcite cement suggest that the Jauf reservoir lost a significant amount of primary porosity at a very early stage of its diagenetic history. Early calcite cement, however, prevented the later compaction of the sandstone, thus preserving an unfilled part of the primary porosity. Based on the framework grain-cement relationships, precipitation of the early calcite cement was either accompanied or followed by the development of part of the pore-lining and pore-bridging clay cement. Secondary porosity development occurred due to partial to complete dissolution of early calcite cements and feldspar. Late calcite cement occurs as isolated patches, and has little impact on reservoir quality of the sandstones. In addition to calcite, several different clay minerals including illite and chlorite occur as pore-filling and pore-lining cements. While the pore-filling illite and chlorite resulted in a considerable loss of porosity, the pore-lining chlorite may have helped in retaining the porosity by preventing the precipitation of syntaxial quartz overgrowths. Illite, which largely occurs as hair-like rims around the grains and bridges on the pore throats, caused a substantial deterioration to permeability of the

  9. Hydrothermal alterations and O, H, C isotopic characterization of fluids and minerals in uraniferous massif of Saint Sylvestre (France). Extension to other French intragranitic uranium deposits

    International Nuclear Information System (INIS)

    Petrographical, mineralogical, geochemical and stable isotope (18O/16O, D/H, 13C/12C) studies have been performed on the leucogranitic massif of St Sylvestre (Limousin, Massif Central francais), particularly on the different hydrothermal alterations. The oxygen isotope geochemistry of granites confirms the unicity of the different facies and their sialic origin (delta18O whole rocks = +11.0 +- 0.5 per mill), with a major contribution of detritic sediments rich in organic matter and poor in carbonate (delta13C magm. CO2 = -10.6 per mill). Late lamprophyres have a deep-seated origin (delta18O = + 6 per mill). The pervasive chloritization of granitic biotites occurs during the convective circulation of a fluid of meteoric origin, at temperatures around 350-4500C. The chemical composition of chlorite which is buffered by that of biotite and the large 18O-shift of fluid towards high delta values indicate that water-rock ratio was not very high. Chloritization takes place in high permeability zones. In regions where porosity is generally low, fluids are ''canalised'' in localised micro-fissured zones. Very high water/rock ratios lead to the dissolution of quartz, and the formation of the ''feldspathic episyenite'' alteration facies. The isotopic features of this fluid (delta18O approximately - 8 per mill, deltaD approximately - 50 per mill) indicate an elevated altitude. An isotopically similar fluid is responsible for the later ''micaceous episyenite'' alteration facies, found in fractured zones. Mixing of this fluid with a sedimentary fluid (delta18O approximately + 10 per mill, deltaD approximately - 30 per mill, delta13C approximately - 18 per mill) yielded the conditions necessary for the deposit of primary economic ore. Such fluids, sedimentary or metamorphic in origin, have been recognized in most hercynian intragranitic U and Sn-W deposits

  10. Animal-sediment interactions: the effect of ingestion and excretion by worms on mineralogy

    Directory of Open Access Journals (Sweden)

    S. J. Needham

    2004-01-01

    Full Text Available By controlled experiments that simulate marine depositional environments, it is shown that accelerated weathering and clay mineral authigenesis occur during the combined process of ingestion, digestion and excretion of fine-grained sediment by two species of annelid worms. Previously characterized synthetic mud was created using finely ground, low-grade metamorphic slate (temperature approximately 300°C containing highly crystalline chlorite and muscovite. This was added to experiment and control tanks along with clean, wind-blown sand. Faecal casts were collected at regular intervals from the experimental tanks and, less frequently, from the control tanks. Over a period of many months the synthetic mud (slate proved to be unchanged in the control tanks, but was significantly different in faecal casts from the experimental tanks that contained the worms Arenicola marina and Lumbricus terrestris. Chlorite was preferentially destroyed during digestion in the gut of A. marina. Both chlorite and muscovite underwent XRD peak broadening with a skew developing towards higher lattice spacing, characteristic of smectite formation. A neoformed Fe-Mg-rich clay mineral (possibly berthierine and as-yet undefined clay minerals with very high d-spacing were detected in both A. marina and L. terrestris cast samples. We postulate that a combination of the low pH and bacteria-rich microenvironment in the guts of annelid worms may radically accelerate mineral dissolution and clay mineral precipitation processes during digestion. These results show that macrobiotic activity significantly accelerates weathering and mineral degradation as well as mineral authigenesis. The combined processes of sediment ingestion and digestion thus lead to early diagenetic growth of clay minerals in clastic sediments.

  11. Animal-sediment interactions: the effect of ingestion and excretion by worms on mineralogy

    Directory of Open Access Journals (Sweden)

    D. McIlroy

    2004-09-01

    Full Text Available By controlled experiments that simulate marine depositional environments, it is shown that accelerated weathering and clay mineral authigenesis occur during the combined process of ingestion, digestion and excretion of fine-grained sediment by two species of annelid worms. Previously characterized synthetic mud was created using finely ground, low-grade metamorphic slate (temperature approximately 300°C containing highly crystalline chlorite and muscovite. This was added to experiment and control tanks along with clean, wind-blown sand. Faecal casts were collected at regular intervals from the experimental tanks and, less frequently, from the control tanks. Over a period of many months the synthetic mud (slate proved to be unchanged in the control tanks, but was significantly different in faecal casts from the experimental tanks that contained the worms Arenicola marina and Lumbricus terrestris. Chlorite was preferentially destroyed during digestion in the gut of A. marina. Both chlorite and muscovite underwent XRD peak broadening with a skew developing towards higher lattice spacing, characteristic of smectite formation. A neoformed Fe-Mg-rich clay mineral (possibly berthierine and as-yet undefined clay minerals with very high d-spacing were detected in both A. marina and L. terrestris cast samples. We postulate that a combination of the low pH and bacteria-rich microenvironment in the guts of annelid worms may radically accelerate mineral dissolution and clay mineral precipitation processes during digestion. These results show that macrobiotic activity significantly accelerates weathering and mineral degradation as well as mineral authigenesis. The combined processes of sediment ingestion and digestion thus lead to early diagenetic growth of clay minerals in clastic sediments.

  12. Structure and geochemistry of the Rise and Shine Shear Zone mesothermal gold system, Otago Schist, New Zealand

    International Nuclear Information System (INIS)

    The Rise and Shine Shear Zone is a late metamorphic deformation zone developed in biotite zone Textural Zone 4 schist in Central Otago. The shear zone has been hydrothermally altered, with addition of gold associated with replacement of schist minerals by pyrite and arsenopyrite. Hydrothermal alteration of schist during mineralisation involved replacement of titanite by rutile, recrystallisation of metamorphic quartz, muscovite and chlorite, and addition of ankerite. Mineralised schist has abundant microshears that have developed parallel and subparallel to the pervasive schist foliation, and these microshears contain much of the hydrothermal sulfides and gold. Microshears have been deformed locally by upright syn-mineralisation brittle reverse faults and angular folds that have a southerly axial trend. These more brittle deformation zones are confined to the Rise and Shine Shear Zone. Gold-bearing veins and mineralised breccias, made up of quartz, albite, pyrite, arsenopyrite, calcite, and chlorite, fill extensional sites associated with upright fold zones. Calcite delta18OVSMOW from these late-stage mineralised veins ranges from +7 to +15 per mille and δ13CPDB from -5.3 to -6.6 per mille, are similar to many other gold-bearing vein systems in Otago, but are distinctly different from the Macraes deposit. Mineralisation occurred near to the brittle/ductile transition, at 200-400 degrees C. The upper part of the shear zone was truncated by a shallow northeast-dipping normal fault, the Thomsons Gorge Fault, which juxtaposed shear zone rocks against unmineralised Textural Zone 3 chlorite zone rocks in the middle Cretaceous. The Rise and Shine Shear Zone has some structural and geochemical features in common with the Hyde-Macraes Shear Zone, but also some important differences, and is not a simple strike-extension of that structure. (author). 46 refs., 9 figs., 3 tabs

  13. Mineralogía y génesis de las arcillas de las unidades del Campo de Gibraltar. IV. Unidad de Facinas

    Directory of Open Access Journals (Sweden)

    Ruiz Cruz, M. O.

    1989-08-01

    Full Text Available The Facinas Unit consists of a clayed flysch facies with quartzite and sandstone centimeter layers. According to paleontological data, two beds are distinguished, one lower of Albian-Aptian age, and another, hígher, Upper Cretaceous-Paleocene in age. The mineralogy of the Facinas Unit is very monotonous through all the sequences studied, especially for the concerning to less than 2 fraction. This unít is characterized by an abundance of chlorites of different composition and genesis: Authigenic chlorites are mainly Fe-rich members, whereas chlorites of inherited origin are magnesian. On the other hand, this míneralogical study reveals a common origin and/or evolution for the two beds of the Facinas Unít.Se recogen en este trabajo los resultados obtenidos a partir del estudio mineralógico de la Unidad de Facinas, que presenta dos tramos, uno inferior Albo-Aptense y otro superior Cretácico Superior-Paleoceno. Las secuencias estudiadas muestran una gran similitud litológica y, si bien en las muestras totales se observan ciertas diferencias mineralógicas, la fracción menor de 2 micras es muy homogénea. Caracterizan a esta Unidad la abundancia de cloritas de diferente composición y génesis: cloritas autigénicas, predominantemente ferrosas y cloritas heredadas, magnesianas. Por otra parte, este estudio mineralógico permite indicar un origen y/o evolución común para los dos tramos de la Unidad de Facínas.

  14. Clay mineralogy of the Boda Claystone Formation (Mecsek Mts., SW Hungary)

    Science.gov (United States)

    Németh, Tibor; Máthé, Zoltán; Pekker, Péter; Dódony, István; Kovács-Kis, Viktória; Sipos, Péter; Cora, Ildikó; Kovács, Ivett

    2016-04-01

    Boda Claystone Formation (BCF) is the host rock of the planned site for high level nuclear waste repository inHungary. Samples representing the dominant rock types of BCF were studied: albitic claystone, claystone with high illite content, and analcime bearing claystone. Clay minerals in these three rock types were characterized by Xray powder diffraction (XRD), transmission electron microscopy (TEM) and thermal analysis (DTA-TG), and the results were discussed from the point of view of the radionuclide sorption properties being studied in the future. Mineral compositions of bulk BCF samples vary in wide ranges. In the albitic sample, besides the dominant illite, few percent of chlorite represents the layer silicates in the clay fraction. Illite is the dominating phase in the illitic sample, with a few percent of chlorite. HRTEM study revealed that the thickness of illite particles rarely reaches 10 layers, usually are of 5-6 TOT layer thick. Illite crystals are generally thicker in the albitic sample than in the illitic one. The significant difference between the clay mineral characterisitics of the analcimous and the other two samples is that the former contains regularly interstratified chlorite/smectite beside the dominant illite. Based on the structural and chemical data two illite type minerals are present in the BCF samples: 1M polytype containing octahedral Fe and Mg besides Al, 2M polytype illite generally is free of Fe andMg. Close association of very thin illite plates and nanosized hematite crystals is typical textural feature for BCF. The goal of this study is to provide solid mineralogical basis for further studies focusing on radionuclide sorption properties.

  15. Desalination impacts on the coastal environment: Ash Shuqayq, Saudi Arabia

    International Nuclear Information System (INIS)

    Ash Shuqayq (Saudi Red Sea coast) is approximately 28 km long and characterised by narrow rocky headlands with intermittent pocket beaches. Fifty-two sediment samples from six different environments (beach, dune, sabkha, tidal/lagoon, offshore and wadi) were analysed. Testing showed that beach and dune sands are mainly medium to fine grained, with some very coarse sand (MZ = − 0.59ø). Both beach and dune sands are moderately well to moderately sorted, although some are poorly sorted due to an influx of wadi sediments. Sediment source together with littoral reworking contributed to grain size variation. Carbonate content varied between 1.5% and 23%, whilst the organic content varied between 1.1% and 13%. Spatial analysis showed increasing southward carbonate and organic content, with both correlated (r = 0.57). Sabkha sediments had significantly higher carbonate percentages (t = 2.898; df = 18; p < 0.01) and results suggested origins are similar for both UAE Arabian Sea and Saudi Arabian Red Sea coasts. X-ray diffractions show beach and dune sediments are mainly composed of detrital quartz and plagioclase feldspar with uncommon amounts of chlorites. Analysis of sediment characteristics, composition and shoreline distribution alongside coastal processes, indicate that high chlorite levels are probably caused by desalination processes. Due to human and ecosystem health consequences and the likely increased demand for desalination plants, similar analyses should be undertaken elsewhere, e.g. the Mediterranean. - Highlights: ► New and previously unpublished Red Sea sediment information. ► Sediment chemical and spatial variations established. ► Sabkha origins are similar for both UAE Arabian Sea and Saudi Arabian Red Sea coasts. ► Desalination plant shown as cause of increased marine sediment chlorite levels.

  16. Development of chlorine dioxide releasing film and its application in decontaminating fresh produce.

    Science.gov (United States)

    Ray, Soumi; Jin, Tony; Fan, Xuetong; Liu, Linshu; Yam, Kit L

    2013-02-01

    A feasibility study was conducted to develop chlorine dioxide (ClO(2) )-releasing packaging films for decontaminating fresh produce. Sodium chlorite and citric acid powder were incorporated into polylactic acid (PLA) polymer. Films made with different amounts of PLA (100 and 300 mg), percentages of reactant (5% to 60%), and ratios of sodium chlorite to citric acid (1:2 or 2:1) were prepared using a solvent casting method. The release of ClO(2) from the resultant films was activated by moisture. Increase of reactants in the films produced more ClO(2) while higher PLA content in the films resulted in less release of ClO(2) . The ratio of sodium chlorite to citric acid and activation temperature (22 °C compared with 10 °C) did not affect the ClO(2) release from the films. Antimicrobial efficacy of ClO(2) released from the films was evaluated using grape tomato as a model food. The results indicate that the films were activated by moisture from tomatoes in the package and the released ClO(2) reduced Salmonella spp. and Escherichia coli O157:H7 inoculated on the tomatoes to undetectable levels (<5 colony forming units (CFU)/tomato), achieving more than 3 log reduction. The film-treated tomatoes did not show significant changes in color and texture as compared to controls during storage at 10 °C for 21 d. This study demonstrated the technical feasibility for development of gaseous ClO(2) -releasing packaging system to enhance microbial safety and extend shelf life of fresh produce. PMID:23294122

  17. A study on the ground water flow and hydrogeochemical interaction in fractured rock masses

    International Nuclear Information System (INIS)

    A study site, the Precambrian gneiss complex in the vincinity of Chungyang has been investigated by geologic surface mapping, tunnel mapping and core drilling with chemical analysis and microscopic observation of rock samples and fracture filling materials. Four boreholes at depths between 50 and 200m were drilled. They are located in a potential fracture zone, which was selected based on the topographic characterisitcs and the fracture survey data. The hydraulic characteristics are described based on the results of constant pressure injection test and cross hole test. In the single hole test, the test sections varied between 1 and 5 m. The hydraulic conductivity of local fracture zones ranges from 1xlO-5 to lxlO-7 m/sec whereas that of the intact rock within the depth of 50 m is in the range of 7xlO-8 to 8xlO-9 m/sec. The field dispersivity values obtained from an injection phase range from 0.15 to 4.5 m at varying depths. The whole thickness dispersivity on the 18 m section obtained from a withdrawal phase is 0.4 m. The dispersion test in two well non-circulation mode was carried out along a single fracture set at depth between 11.5-14.5m. The longitudinal dispersivity obtained from the two well test is 8.14 m. The identified minerals of host rocks are quartz, K-feldspar,plagioclase, biotite, muscovite, sericite, chlorite, calcite, pyrite, zircon and opaque minerals. The primary minerals such as feldspar and biotite are highly altered into sericite and chlorite respectively. The fracture-filling materials from core samples identified by as calcite, kaolinite, smectite, chlorite, illitite, quartz, pyrite with fe- and Mn-oxides. (Author)

  18. Fluid inclusion and phase equilibrium studies at the Cannivan Gulch molybdenum deposit, Montana, USA: Effect of CO 2 on molybdenite-powellite stability

    Science.gov (United States)

    Darling, Robert S.

    1994-01-01

    The molybdenum deposit at Cannivan Gulch is characterized by both stockwork- and skarn type mineralization. The vein mineral assemblages, however, differ considerably between the various host rocks. In the Cannivan stock, molybdenite occurs in typical quartz + K-feldspar or quartz + muscovite veins. In the country rocks, molybdenite occurs in chlorite + pyrite + magnetite veins containing variable amounts of quartz, calcite, and epidote. Primary fluid inclusions in quartz and fluorite contain aqueous liquid, CO 2 liquid, and CO 2 vapor (average XCO2 = 0.05). Microthermometric and Laser Raman microspectrographic analyses indicate CO 2 is the principal volatile phase. First melting temperatures in the aqueous portion indicate the dissolved salt is principally NaCl. Final CO 2-clathrate melting temperatures indicate NaCl contents ranging from 2 to 7 wt% relative to H 2O. Homogenization temperatures range from 196 to 272°C. Four chlorite temperatures from two samples range from 296 to 319°C. In P- T space, the four chlorite univariants intersect four fluid inclusion isochores (from the same samples) at temperatures of 300 ± 20° C and 1500 ± 300 bars, which are the inferred P and T of molybdenite formation. Mineral equilibria in vein assemblages from country rocks at Cannivan Gulch indicate fO2 and fS2 conditions of molybdenite formation between the pyrite-pyrrhotite-magnetite and pyrite-magnetite-hematite buffers. Formation of a calcite-molybdenite assemblage over powellite suggests that even small amounts of CO 2 ( XCO2 = 0.05) in an ore fluid greatly extend the stability field of molybdenite to higher oxygen fugacities.

  19. Distribution and composition of authigenic minerals in surface sediments of the western Gulf of Thailand

    Institute of Scientific and Technical Information of China (English)

    WANG Kunshan; SHI Xuefa; QIAO Shuqing; KORNKANITNAN Narumol; KHOKIATTIWONG Somkiat

    2015-01-01

    Generation, morphology, and distribution of authigenic minerals directly reflect sedimentary environment and material sources. Surface sediments were collected from the western Gulf of Thailand during 2011–2012, and 159 samples were analyzed to determine detrital minerals. Authigenic minerals, including siderite, pyrite, and glauconite, are abundant whereas secondary minerals, such as chlorite and limonite, are distributed widely in the study area. Siderite has a maximum content of 19.98 g/kg and appears in three types from nearshore to continental shelf, showing the process of forming-maturity-oxidation. In this process, the MnO content in siderite decreases, but Fe2O3 and MgO content increase. Colorless or transparent siderite pellets are fresh grains generated within a short time and widely distributed throughout the region; high content appears in coastal area where river inputs are discharged. Translucent cemented double pellets appearing light yellow to red are mature grains; high content is observed in the central shelf. Red-brown opaque granular pellets are oxidized grains, which are concentrated in the eastern gulf. Pyrite is mostly distributed in the central continental shelf with an approximately north–south strip. Pyrite are mainly observed in foraminifera shell and distributed in clayey silt sediments, which is similar to that in the Yangtze River mouth and the Yellow Sea. The pyrite in the gulf is deduced from genetic types associated with sulfate reduction and organic matter decomposition. Majority of glauconite are granular with few laminar. Glauconite is concentrated in the northern and southern parts within the boundary of 9.5° to 10.5°N and is affected by river input diffusion. The distribution of glauconite is closely correlated with that of chlorite and plagioclase, indicating that glauconite is possibly derived from altered products of chlorite and plagioclase. The K2O content of glauconite is low or absent, indicating its short

  20. Formation of disinfection byproducts upon chlorine dioxide preoxidation followed by chlorination or chloramination of natural organic matter.

    Science.gov (United States)

    Yang, Xin; Guo, Wanhong; Lee, Wontae

    2013-06-01

    Chlorine dioxide (ClO2) is often used as an oxidant to remove taste, odor and color during water treatment. Due to the concerns of the chlorite formation, chlorination or chloramination is often applied after ClO2 preoxidation. We investigated the formation of regulated and emerging disinfection byproducts (DBPs) in sequential ClO2-chlorination and ClO2-chloramination processes. To clarify the relationship between the formation of DBPs and the characteristics of natural organic matter (NOM), changes in the properties of NOM before and after ClO2 oxidation were characterized by fluorescence, Fourier transform infrared spectroscopy (FTIR), and size and resin fractionation techniques. ClO2 preoxidation destroyed the aromatic and conjugated structures of NOM and transformed large aromatic and long aliphatic chain organics to small and hydrophilic organics. Treatment with ClO2 alone did not produce significant amount of trihalomethanes (THMs) and haloacetic acids (HAAs), but produced chlorite. ClO2 preoxidation reduced THMs, HAAs, haloacetonitriles (HANs) and chloral hydrate (CH) during subsequent chlorination, but no reduction of THMs was observed during chloramination. Increasing ClO2 doses enhanced the reduction of most DBPs except halonitromethanes (HNMs) and haloketones (HKs). The presence of bromide increased the formation of total amount of DBPs and also shifted DBPs to more brominated ones. Bromine incorporation was higher in ClO2 treated samples. The results indicated that ClO2 preoxidation prior to chlorination is applicable for control of THM, HAA and HAN in both pristine and polluted waters, but chlorite formation is a concern and HNMs and HKs are not effectively controlled by ClO2 preoxidation.

  1. Pinite-cordierite from spotted slate of the Brajkovac contact metamorphic aureole (Dudovica locality, central Serbia

    Directory of Open Access Journals (Sweden)

    Vasković Nada

    2013-01-01

    Full Text Available The Paleozoic very low to low-grade metamorphic rocks of the Bukulja-Lazarevac Unit designated as Drina, Golija and Birač formations are contact metamorphosed by the intrusion of the Tertiary Brajkovac granodiorite into spotted slates and hornfelses. In some parts, they are slightly migmatized at the contact. In addition to their outcrops found at the western, eastern and northern parts of the formation, these rocks are also found in boreholes near Dudovica at about 8 km south-west from the pluton. There, at a depth of 110 m, the spotted slates comprise oval to ellipsoid pinite-rich spots which can be regarded as incipient cordierite porphyroblasts (up to 5 mm in diameter overgrowing the existing regional foliation. They are composed of cryptocrystalline mixture of a very fine sericitic material ± light glassy orange „film“ (some kind of an amorphous gel-like material often mixed with limonite matter and are abundant in inclusions: minute quartz and dusty ore minerals (magnetite prevail. In addition, within some spots an increased number of xenotime and monazite inclusions are noted. Minute flakes of neobiotite are formed at the expense of quartz-sericite-chlorite matrix. The secondary chlorite occurring as overgrowths on pinite-cordierite spots shows variable composition (brunsvigite to diabandite. The Mg/Fe+Mg ratio of cryptocrystalline pinitic mixture ranges from 0.14-0.67. The Si vs AlIV+AlVI relations deviate from the ideal muscovite-phengite join due to Tschermak substitution towards chloritic composition or a more complex mixture, including clay minerals (which reflected a decrease of Altot and Si with increase of Fe2+. Obtained data indicates that the cordierite-pinite spots can be related to contact metamorphic processes that occurred within the temperature range 300-450°C. [Projekat Ministarstva nauke Republike Srbije, br. 176019 i br. 176016

  2. Clay mineralogy in agrochernozems of western Ukraine

    Science.gov (United States)

    Papish, I. Ya.; Chizhikova, N. P.; Poznyak, S. P.; Varlamov, E. B.

    2016-10-01

    The mineralogy of clay fractions separated from deep low-humus deep-gleyic loamy typical agrochernozems on loess-like loams of the Upper Bug and Dniester uplands in the Central Russian loess province of Ukraine consists of complex disordered interstratifications with the segregation of mica- and smectite-type layers (hereafter, smectite phase), tri- and dioctahedral hydromicas, kaolinite, and chlorite. The distribution of the clay fraction is uniform. The proportions of the layered silicates vary significantly within the profile: a decrease in the content of the smectite phase and a relative increase in the content of hydromicas up the soil profile are recorded. In the upper horizons, the contents of kaolinite and chlorite increase, and some amounts of fine quartz, potassium feldspars, and plagioclases are observed. This tendency is observed in agrochernozems developed on the both Upper Bug and Dniester uplands. The differences include the larger amounts of quartz, potassium feldspars, and plagioclases in the clay material of the Upper Bug Upland, while the contents of the smectite phase in the soil profiles of the areas considered are similar. An analogous mineral association is noted in podzolized agrochernozems on loess-like deposits in the Cis-Carpathian region of the Southern Russian loess province developed on the Prut-Dniester and Syan-Dniester uplands. The distribution of particle-size fractions and the mineralogy of the clay fraction indicate the lithogenic heterogeneity of the soil-forming substrate. When the drifts change, the mineral association of the soils developed within the loess-like deposits gives place to minerals dominated by individual smectite with some mica-smectite inter stratifications, hydromicas, and chlorite.

  3. Relation between the complex Ginzburg-Landau equation and reaction-diffusion System

    Institute of Scientific and Technical Information of China (English)

    Shao Xin; Ren Yi; Ouyang Qi

    2006-01-01

    The complex Ginzburg-Landau equation(CGLE)has been used to describe the travelling wave behaviour in reaction-diffusion (RD) systems. We argue that this description is valid only when the RD system is close to the Hopf bifurcation,and is not valid when a RD system is away from the onset.To test this,we study spirals and anti-spirals in the chlorite-iodide-malonic acid (CIMA) reaction and the corresponding CGLE.Numerical simulations confirm that the CGLE can only be applied to the CIMA reaction when it is very near the Hopf onset.

  4. 福岡県水田土壌粘土鉱物地図の作成

    OpenAIRE

    江頭, 和彦; 田中, 有希

    1997-01-01

    Fukuoka prefecture has 78,800 ha of paddy soils occupying 15.9% of the whole prefectural area. Analytical data of clay mineralogical composition of paddy soils was used for the preparation of a map of clay mineral distribution. Based on the mineral index and the magnitude of specific surface area, 288 paddy soil samples were classified into 6 categories. Namely, “smectite-dominant”, “smectite-abundant”, “smectite-fair”, “chlorite-type”, “kaolin mineral-type”, and “noncrystalline/layersilicate...

  5. Geothermal alteration of clay minerals and shales: diagenesis

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, C.E.

    1979-07-01

    The objective of this report is to perform a critical review of the data on the mineral and chemical alterations that occur during diagenesis and low-grade metamorphism of shale and other clay-rich rocks - conditions similar to those expected from emplacement of heat-producing radioactive waste in a geologic repository. The conclusions drawn in this document are that the following type of alterations could occur: smectite alteration, ion mobilization, illitic shales, kaolinite reactions, chlorite reactions, organic reactions, paleotemperatures, low temperature shales, high temperature shales, and phase equilibrium changes.

  6. Effets thermique et hydrothermal de la coulée de basalte triasico-liasique sur les argiles du bassin d'Argana (Maroc)Thermal and hydrothermal effects of Triassic Liassic basalt flow deposition on clays (Agana Basin, Morocco)

    Science.gov (United States)

    Daoudi, Lahcen; Pot de Vin, Jean-Luc

    Thermal and hydrothermal effects of Triassic-Liassic basalt flow deposition on sedimentary series of the Argana Basin are responsible for major modifications in detrital clays, until 20 m in depth. It expressed by transformation of detrital smectite to corrensite and moreover to chlorite, and by increasing illite crystallinity. On the 2 m of sediments located immediately under the flow, magnesium-rich hydrothermal fluids have caused precipitation of new mineral phases. To cite this article: L. Daoudi, J.-L. Pot de Vin, C. R. Geoscience 334 (2002) 463-468.

  7. Lead isotope compositions as guides to early gold mineralization: The North Amethyst vein system, Creede district, Colorado

    Science.gov (United States)

    Foley, Nora K.; Ayuso, Robert A.

    1994-01-01

    The North Amethyst vein system, which is hosted by approximately 27 Ma Carpenter Ridge Tuff and approximately 26 Ma Nelson Mountain Tuff, has two mineral associations separated by brecciation and sedimentation in the veins. The early association consists of quartz, rhodonite, hematite, magnetite, electrum (Au (sub 0.3-0.5) Ag (sub 0.7-0.5)) , and Mn carbonate, Au-Ag sulfide, Ag sulfosalt, and base metal sulfide minerals. The later mineral association cuts the Mn- and Au-bearing assemblages and consists of quartz, calcite, sericite, chlorite, hematite, adularia, fluorite, base metal sulfides, and Ag-bearing tetrahedrite.

  8. Chitooligosaccharide-2,5-anhydro-D-mannonic Acid

    Directory of Open Access Journals (Sweden)

    Emil Salim

    2014-08-01

    Full Text Available Chitooligosaccharide with one 2,5-anhydro-D-mannofuranose unit at the reducing end (COSamf was prepared by nitrous deamination of fully N-deacetylated chitosan. The oxidation of the amf-unit by chlorite sodium was achieved in high yield. The chemical structure of the targeted chitooligosaccharide-2,5-anhydro-D-mannonic acid with a degree of polymerization ~10 was fully characterized by NMR spectroscopy, MALDI-TOF mass spectrometry and size-exclusion chromatography. The success of this synthesis opens the way to a new generation of end-functionalized COS building blocks.

  9. Mineral resource of the month: vermiculite

    Science.gov (United States)

    Tanner, Arnold O.

    2014-01-01

    Vermiculite comprises a group of hydrated, laminar magnesium-aluminum-iron silicate minerals resembling mica. They are secondary minerals, typically altered biotite, iron-rich phlogopite or other micas or clay-like minerals that are themselves sometimes alteration products of amphibole, chlorite, olivine and pyroxene. Vermiculite deposits are associated with volcanic ultramafic rocks rich in magnesium silicate minerals, and flakes of the mineral range in color from black to shades of brown and yellow. The crystal structure of vermiculite contains water molecules, a property that is critical to its processing for common uses.

  10. On the possibilities of occurrence of structure controlled unconformity-proximal uranium mineralization in Madhawanpalli - Rayalgandi Sector, Srisailam Sub-Basin, Cuddapah Basin, Andhra Pradesh

    International Nuclear Information System (INIS)

    The northern margin of Srisailam Sub-basin is well known for its potential to host unconformity proximal uranium mineralization and so far three deposits have been established at Lambapur, Peddagattu and Chitrial. Recent exploration in Madhawanpalli-Rayalgandi sector and follow up sub-surface exploration has indicated uranium mineralization in the granites beneath the cover of Srisailam sediments. The host rock is characterized by intense fracturing, brecciation, cataclasism and alterations like chloritization, illitization and silicification signifying the role of basement structures in uranium mineralization near the unconformity surface. (author)

  11. Clay mineral distribution in surface sediments of the South China Sea and its significance for in sediment sources and transport

    Institute of Scientific and Technical Information of China (English)

    刘建国; 陈木宏; 陈忠; 颜文

    2010-01-01

    Clay minerals of surface sediments in the South China Sea (SCS) are analyzed with X-ray diffraction, and their transport is explored with a grain size trend analysis (GSTA) model. Results show that clay mineral types in various sedimentary environments have different sediment sources and transport routes. Sediments in the northern SCS (north of 20°N) between the southwest of Taiwan Island and the outer mouth of the Pearl River have high contents of illite and chlorite, which are derived mainly from sediment...

  12. The geology and mineralogy of the uranium occurrence at Hoehensteinweg near Poppenreuth (NE Bavaria) - a model of its mode of formation

    International Nuclear Information System (INIS)

    The uranium mineralization consists of U oxides, U titanates, U silicates and secondary U minerals, arranged roughly in order of crystallization. These ores are associated with muscovite, chlorite and smectite. The non-uranium mineralization consists of scheelite, arsenopyrite, native gold, pyrite/chalcopyrite, Bi/Pb-selenides, sulphides and iron sulphides. Scheelite only occurs in the outermost part of the granite (e.g. at Tirschenreuth). Isotope disequilibria show that further redeposition of uranium minerals probably took place in joints and alteration zones in recent or sub-recent times. The uranium mineralization is, on the basis of its geological setting, comparable with the Spanish deposits of Iberian type. (orig./HP)

  13. Geothermal alteration of clay minerals and shales: diagenesis

    International Nuclear Information System (INIS)

    The objective of this report is to perform a critical review of the data on the mineral and chemical alterations that occur during diagenesis and low-grade metamorphism of shale and other clay-rich rocks - conditions similar to those expected from emplacement of heat-producing radioactive waste in a geologic repository. The conclusions drawn in this document are that the following type of alterations could occur: smectite alteration, ion mobilization, illitic shales, kaolinite reactions, chlorite reactions, organic reactions, paleotemperatures, low temperature shales, high temperature shales, and phase equilibrium changes

  14. Les argiles bleues du Cambrien inférieur de Saint-Pétersbourg et leur fissuration. Implications pour des stockages souterrainsLower Cambrian Saint Petersburg blue clays and their fissuration. Implication for underground stages

    Science.gov (United States)

    Arnould, Marcel; Boisson, Jean-Yves; Ivanov, Ivan P.

    2002-12-01

    The Lower Cambrian Saint Petersburg blue clays are composed of predominant illite and chlorite, sometimes accompanied by kaolinite. The <0.1 μm fraction has a high content of illite-smectite mixed layers. Particle-size distribution is more than 50% of clay particles and about 30% of silts. These blue clays correspond to plastic (and soft) clays; they may be compared to the Callovian clays of Bure (France), where storage of natural waste is envisaged. To cite this article: M. Arnould et al., C. R. Geoscience 334 (2002) 1135-1140.

  15. Metabolism and pharmacokinetics of alternate drinking water disinfectants.

    OpenAIRE

    Abdel-Rahman, M S; Couri, D; Bull, R J

    1982-01-01

    The chlorination of surface waters is known to elevate trihalomethanes; consequently, chlorine dioxide (ClO2) is being considered as an alternative disinfectant. The primary products resulting from ClO2 disinfection of waters are chlorites (ClO2-) and chlorates (ClO3-). Studies in rats revealed that ClO2 is converted to chloride (Cl-), ClO2- and ClO3-. ClO2- and ClO3- are excreted as Cl-, ClO2- and Cl-, ClO2-, ClO3-, respectively. Radioactivity was rapidly absorbed from the gastrointestinal t...

  16. Advantages and disadvantages of chemical oxidation and disinfection by ozone and chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Fiessinger, F.; Richard, Y.; Montiel, A.; Musquere, P.

    1981-04-01

    Ozone and chlorine dioxide present definite advantages and disadvantages over chlorination. Chlorination, particularly for the removal of ammonia and the maintenance of a disinfectant residual in the distribution system has decisive advantages and will be difficult to replace. Ozone and chlorine dioxide seem to produce fewer carcinogenic by-products but the risk for acute toxicity, especially from the chlorites which follow chlorine dioxide, is higher than with chlorine. Chlorine dioxide and more particularly ozone should be considered as useful complements to chlorination, but no strong oxidative treatment should be applied before most of the organic matter has been removed.

  17. Arc Magma Genesis from Melting of Mélange Diapirs

    Science.gov (United States)

    Cruz-Uribe, A. M.; Marschall, H.; Gaetani, G. A.

    2015-12-01

    Alkaline basalts occur in many subduction-related volcanic settings, including the Sunda, Izu-Bonin, Honshu, Aeolian, and Aleutian arcs, yet their origin continues to be debated. Recent studies have suggested that buoyant material (mélange) from the slab-wedge interface may rise into the hot corner of the mantle wedge as low-density plumes or diapirs, where it will melt or induce mantle melting due to dehydration. High-pressure mélange rocks represent a mixture of mafic, ultramafic, and sedimentary components, and are often dominated by chlorite. Mélange rocks are also enriched in accessory phases such as monazite, zircon, and rutile, which host a variety of trace elements. We present results from experimental melting of chlorite-rich mélange material at mantle wedge conditions that reproduce many of the compositional features of subduction-related lavas. Piston cylinder experiments were performed at conditions appropriate for mantle wedge diapirs (1030-1280 °C, 1.5-2.5 GPa) using natural mélange rocks from Syros, Greece. Experimental melts derived from omphacite-epidote-phengite bearing chlorite schists range in composition from basaltic trachyandesites to trachydacites to more alkaline melt compositions (50.7-60.73 wt% SiO2, 7.48-12.93 wt% Na2O+K2O). All of the experimental melts are characterized by high alumina contents (16.79-21.36 wt% Al2O3). Minerals coexisting with these melts include clinopyroxene, amphibole (at lower T) or olivine (at higher T), garnet (at higher P), ilmenite and/or rutile, and zircon. Trace element patterns in our experimentally produced melts are similar to those from arc volcanoes worldwide. Experimental melts are enriched in large ion lithophile elements (Cs, Rb, Ba, K, Pb, Sr) and depleted in high field strength elements (Nb, Ta, and Ti). Zirconium and Hf are enriched relative to the rare earth elements (REE), which show flat to heavy REE depleted patterns depending on the presence of residual garnet. Thorium is fractionated

  18. Contact Electrification of Regolith Particles and Chloride Electrolysis: Synthesis of Perchlorates on Mars

    Science.gov (United States)

    Tennakone, K.

    2016-10-01

    Contact electrification of chloride-impregnated martian regolith particles due to eolian agitation and moisture condensation on coalesced oppositely charged grains may lead to spontaneous electrolysis that generates hypochlorite, chlorite, chlorate, and perchlorate with a concomitant reduction of water to hydrogen. This process is not curtailed even if moisture condenses as ice because chloride ionizes on the surface of ice. Limitations dictated by potentials needed for electrolysis and breakdown electric fields enable estimation of the required regolith grain size. The estimated dimension turns out to be of the same order of magnitude as the expected median size of martian regolith, and a simple calculation yields the optimum rate of perchlorate production.

  19. Silver-cobalt mineralization in the Upper Seymchan ore cluster, Northeastern Russia

    Science.gov (United States)

    Goryachev, N. A.; Gamyanin, G. N.; Prokof'ev, V. Yu.; Savva, N. E.; Velivetskaya, T. A.; Ignat'ev, A. V.

    2014-09-01

    This paper is focused on the Early Cretaceous Ag-Bi-Co-sulfoarsenide mineralization atypical of northeastern Asia, which contains diverse Co-Ni sulfoarsenides, Se-bearing Bi sulfotellurites, and Ag-Bi-Pb sulfosalts. The Upper Seymchan ore cluster is located at the boundary between the Paleozoic Omulevka Terrane of carbonate platform and the In'yali-Debin Synclinorium of the Kular-Nera Terrane. These ore-bearing sequences are represented by the Middle Jurassic terrigenous rocks that rest upon the Upper Triassic sandshale rocks of the upper structural stage. The sedimentary rocks are cut through by high-Al granitic plutons and younger granite-porphyry dikes. The orebodies that are superposed on igneous rocks were formed during (1) the quartz-chlorite-tourmaline stage of metasomatic alteration, (2) the main economic tourmaline-chlorite-quartz-sulfoarsenide vein stage, (3) the polysulfide-quartz stage with Ag, Se, Bi minerals, and (4) the postore quartz-calcite stage with fluorite. The epithermal veins of festoon chalcedony-like quartz with Sb-bearing arsenopyrite occupy a special position. In particular orebodies, the chlorite-quartz ore veins dominate at the upper levels, whereas the quartz-tourmaline veins occur at the lower levels. Wall-rock alteration is represented by metasomatic chloritization and tourmalinization up to the formation of monomineralic metasomatic zones. Sulfides and sulfoarsenides are distinguished by anomalous enrichment of sulfur in the light isotope (δ34S = -12.8 to -16.7‰) in contrast to the sulfur isotopic composition of Sb-asenopyrite (-1.7‰) from the genetically different epithermal veins. The oxygen isotopic composition of calcite (the third stage) is uniform at all studied deposits and reveals a tendency to updip enrichment in δ18O within a vertical interval of 200 m. Quartz from ore-bearing and epithermal veins has an almost identical δ18O value (±2‰) but differs from quartz at the tin deposits related to granites of the

  20. [First results on the use of chloramines to reduce disinfection byproducts in drinking water].

    Science.gov (United States)

    Azara, Antonio; Muresu, Elena; Dettori, Marco; Ciappeddu, Pierluigi; Deidda, Antonio; Maida, Alessandro

    2010-01-01

    The presence of disinfection byproducts (DBP) in drinking water raises concerns about the safety of chlorination and is one of the problems inherent the use of surface water as a source of drinking water. In order to reduce the presence of DBP (in particular of chlorites), we evaluated the combined use of chlorine dioxide for primary disinfection and monochloramine for residual disinfection in a water purification plant and distribution system in Sardinia (Italy). The results are very encouraging. Disinfection byproducts were reduced and other parameters were found to be within the recommended standards, indicating further improvements of the purification process.

  1. Petrological studies of plutonic rocks of Ecuador

    International Nuclear Information System (INIS)

    The feldspars of many tonalitic plutonic rocks in the coastal regions and West Andean regions are zoned. This leads to the conclusion that they are relatively flat intrusions and to some extent transition rocks in the subvulcanite direction. This is in accordance with the genetic and chronological relationship between plutonites and the surrounding vulcanites of the Basic Igreous Complex (BIC). The composition of representative minerals, e.g. alkali feldspar, plagioclase feldspar, biotite, chlorite, and amphibole has been determined as well as the age of plutonite samples by the K/Ar dating method. (DG)

  2. Mineralogical study on volcanic ash of the eruption on September 27, 2014 at Ontake volcano, central Japan: correlation with porphyry copper systems

    Science.gov (United States)

    Minami, Yusuke; Imura, Takumi; Hayashi, Shintaro; Ohba, Tsukasa

    2016-04-01

    The volcanic ash of the eruption on September 27, 2014 at Ontake volcano consists mostly of altered rock fragments. The ash contains partly altered volcanic rock fragments consisting of primary igneous minerals (plagioclase, orthopyroxene, titanomagnetite, and feldspars) and volcanic glass accompanied by alteration minerals to some extents, and contains no juvenile fragments. These features indicate that the eruption was a non-juvenile hydrothermal eruption that was derived from the hydrothermal system developed under the crater. The major minerals derived from hydrothermal alteration zones are silica mineral, kaolin-group mineral, smectite, pyrophyllite, muscovite, alunite, anhydrite, gypsum, pyrite, K-feldspar, albite, and rutile. Minor chlorite, biotite, and garnet are accompanied. Five types of alteration mineral associations are identified from observations on individual ash particles: silica-pyrite, silica-pyrite ± alunite ± kaolin, silica-pyrophyllite-pyrite, silica-muscovite ± chlorite, and silica-K-feldspar ± albite ± garnet ± biotite. The associations indicate development of advanced argillic, sericite, and potassic alteration zones under the crater. Occurrence of anhydrite veinlet and the set of alteration zones indicate hydrothermal alteration zones similar to late-stage porphyry copper systems. Comparing the mineral associations with the geologic model of the late-stage porphyry copper systems, the source depths of mineral associations are estimated to range from near surface to >2 km. The depths of advanced argillic alteration, sericite, and potassic zones are 0 to ~2, ~1.5 to ~2, and >2 km, respectively.

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

    Science.gov (United States)

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

    2003-01-01

    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 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.

  4. X-Ray Diffraction (XRD and X-Ray Fluorescence (XRF Analysis of Proto-historic Votive Tablets from Chawas Cave, Hulu Kelantan, Malaysia

    Directory of Open Access Journals (Sweden)

    Zuliskandar Ramli

    2014-02-01

    Full Text Available This research was conducted to determine the origin of votive tablets found in prehistoric and proto-historic site of Chawas Cave in Hulu Kelantan. The votive tablets found in Chawas Cave showed several Buddhist images which are associated with the Srivijaya Kingdom which existed from 7th century AD until 12th century AD. To determine if the votive tablets were produced by communities that lived in Hulu Kelantan, hence the study of the chemical composition of the votive tablets should be carried out. Two techniques were employed in this research, namely the X-Ray Diffraction (XRD and X-Ray Fluorescence (XRF techniques. The techniques will determine the mineral content as well as the major and trace element content of the votive tablets. Analysis showed that all the votive tablet samples have mineral known as clinochlore. Clinochlore is one of the chlorites, namely a group of phyllosilicate minerals. Chlorite is commonly found in igneous rocks as an alteration product of mafic minerals such as pyroxene, amphibole and biotite. The votive tablets were found in a cave which consisted of limestone cave formation and it showed that the votive tablets were not produced by the local community of Hulu Kelantan. Major elements also showed that the chemical composition of the votive tablets is not similar to the composition of clay samples taken from several rivers in Hulu Kelantan.

  5. Fluid inclusion and stable isotope study of telluride mineralization at Mahd Adh Dhahab, Saudi Arabia

    Energy Technology Data Exchange (ETDEWEB)

    Afifi, A.M.; Kelly, W.C.

    1985-01-01

    Mahd Adh Dhahab is unique among Precambrian gold deposits in that it displays many characteristics of epithermal precious metal districts. Au-Ag-Cu-Zn-Pb mineralization occurs principally in the third of five generations of quartz veins. Sulfur isotopic equilibrium was generally maintained among sulfides which range in delta/sup 34/S from -1.8 (galena) to 6.4 (pyrite). The narrow range in delta/sup 34/S of sulfides is inconsistent with large variations in f02 calculated from chlorite +/- pyrite +/- hematite assemblages. Galena-sphalerite pairs yield temperatures in the range 160-270/sup 0/C for stage 3 veins, which fall within the 120-300/sup 0/C range defined by fluid inclusion thermometry. Fluid salinities are in the range 0.5 wt.% NaCl equivalent. The trends indicate mixing of delta/sup 18/O approx. = 0 waters with heavier more oxidized waters during stage 4 deposition which led to non-equilibrium oxidation of H/sub 2/S. deltaD values of vein chlorites fall within a narrow range of -65 to -75, while deltaD measurements of inclusion fluids in quartz display a wider spread from -13 to -43; the lighter values may reflect contamination by secondary inclusions. The stable isotope data indicate probable derivation of both sulfur and carbon from igneous sources. District-wide variation in sulfur and oxygen isotopes indicate the presence of several hydrothermal centers, which has possible significance to exploration.

  6. Geology and geochemistry of palaeoproterozoic low-grade metabasic volcanic rocks from Salumber area, Aravalli Supergroup, NW India

    Indian Academy of Sciences (India)

    L S Shekhawat; M K Pandit; D W Joshi

    2007-12-01

    The Palaeoproterozoic Aravalli Supergroup in Salumber region includes a basal unit of metabasic volcanic rocks (Salumber volcanic rocks) overlain by a volcaniclastic/conglomerate one. Although these volcanic rocks have been metamorphosed to green-schist facies, some primary volcanic features are still preserved. This metabasic volcanic sequence can be further differentiated on the basis of textural variations, and the mineral assemblages are: (a) oligoclase + actinolite + chlorite + epidote; and (b) oligoclase + hornblende+ chlorite + biotite + Fe-Ti oxides. The SiO2 content ranges from ∼47.7 to 55.8% and MgO from ∼4.2 to 12.8%. Geochemical characteristics allow their subdivision into high Mg and Fe tholeiites. Inverse relationship of MgO with silica, alkalis and Zr is generally consistent with fractionation mechanism, also suggested by a change in colour of the rocks from dark greenish to light greenish towards the upper parts of the sequence. These metabasic volcanic rocks are enriched in incompatible trace elements and LREE (La = 30 − 40 × chondrite, Lu = 2 − 5 × chondrite), and demonstrate affinity mainly with MORB and within plate settings in geochemical tectonic discrimination schemes. The geochemical characteristics suggest a complex evolutionary history envisaging derivation of the melt from an enriched heterogeneous lithospheric source.

  7. Bentonite alteration due to thermal-hydro-chemical processes during the early thermal period in a nuclear waste repository

    Energy Technology Data Exchange (ETDEWEB)

    Xu, T.; Senger, R.; Finsterle, S.

    2011-02-01

    After closure of an underground nuclear waste repository, the decay of radionuclides will raise temperature in the repository, and the bentonite buffer will resaturate by water inflow from the surrounding host rock. The perturbations from these thermal and hydrological processes are expected to dissipate within hundreds to a few thousand years. Here, we investigate coupled thermal-hydro-chemical processes and their effects on the short-term performance of a potential nuclear waste repository located in a clay formation. Using a simplified geometric configuration and abstracted hydraulic parameters of the clayey formation, we examine geochemical processes, coupled with thermo-hydrologic phenomena, and potential changes in porosity near the waste container during the early thermal period. The developed models were used for evaluating the mineral alterations and potential changes in porosity of the buffer, which can affect the repository performance. The results indicate that mineral alteration and associated changes in porosity induced by early thermal and hydrological processes are relatively small and are expected to not significantly affect flow and transport properties. Chlorite precipitation was obtained in all simulation cases. A maximum of one percent volume fraction of chlorite could be formed, whose process may reduce swelling and sorption capacity of bentonite clay, affecting the performance of the repository. llitisation process was not obtained from the present simulations.

  8. Change of iron species and iron solubility in Asian dust during the long-range transport from western China to Japan

    Directory of Open Access Journals (Sweden)

    Y. Takahashi

    2011-07-01

    Full Text Available In the North Pacific, transport and deposition of mineral dust from Asia appear to be one of major sources of iron which can regulate growth of phytoplankton in the ocean. In this process, it is essential to identify chemical species of iron contained in Asian dust, because bioavailability of iron in the ocean is strongly influenced by the solubility of iron, which in turn is dependent on iron species in the dust. Here, we report that clay minerals (illite and chlorite in the dusts near the source (western China are transformed into ferrihydrite by atmospheric chemical processes during their long-range transport to eastern China and Japan based on the speciation by X-ray absorption fine structure (XAFS and other methods such as X-ray diffraction and chemical extraction. Moreover, it was found that iron in the dust after the transport becomes more soluble in our leaching experiments conducted for 24 h compared with those for initial dusts possibly due to the formation of ferrihydrite in the atmosphere. Our findings suggested that ferrihydrite secondarily formed during the transport is an important source of soluble iron species, which can be more soluble than clay minerals initially contained in the mineral dust such as illite and chlorite.

  9. Diagenesis and Its Effect on Reservoir Quality of Silurian Sandstones, Tabei Area, Tarim Basin, China

    Institute of Scientific and Technical Information of China (English)

    Zhang Jinliang; Jia Ying; Du Guilin

    2007-01-01

    The diagenetic processes of the Tabei sandstones in the Tarim Basin include compaction, cementation (quartz overgrowths, calcite, clay minerals and a minor amount of pyrite), and dissolution of the feldspar and calcite cement.Porosity was reduced by compaction from an assumed original 40% to about 22.1%. Cementation reduced porosity to 26.6%. The Tabei sandstones lost a little more porosity by compaction than by cementation. Quartz cementation,especially syntaxial quartz overgrowth, is a major cause of porosity-loss in many reservoirs in moderately to deeply buried sandstone. Calcite cementation played a key role in the porosity evolution of sandstones. At the early stage of burial, the early calcite cement occupied most of the pore spaces resulting in significant porosity. On the other hand, some primary porosity has been preserved due to incomplete filling or the presence of scattered patches of calcite cement. In addition to calcite, several clay minerals, including illite and chlorite occurred as pore-filling and pore-lining cements.The pore-lining chlorite may have helped in retaining the porosity by preventing the precipitation of syntaxial quartz overgrowths. Illite, which largely occurred as hair-like rims around the grains and bridges on the pore throats, caused a substantial deterioration of penetrability of the reservoir. Calcite cement dissolution was extensive and contributed significantly to the development of secondary porosity.

  10. A preliminary investigation of microcracks in the overcored borehole 210-020-RST1, 240 level of the Underground Research Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, R.G.

    1992-05-01

    A section of borehole 210-020-RST1 was sampled and thin sections were cut in order to investigate the occurrence of microcracks within the borehole. The petrology of the sample was described and the presence of microcracks was noted. In total, 1894 microcracks were recorded during the investigation. Microcrack sets were defined on the basis of filling type (or lack of filling) and three-dimensional orientations attributed to the microcrack sets based on structural observations. Many microcrack sets are shown to have similar orientations to mesoscopic fractures observed within the Underground Research Laboratory (URL) lease area and within the URL subsurface. The relative age of observed microcracks, in terms of fillings, is from oldest to youngest: fluid-inclusion-filled fractures; unknown filled fractures; chlorite-filled fractures; and coeval in formation, chlorite-, hematite- and sericite-filled fractures. Fractures without filling are considered the youngest. Plates documenting some observed fractures are included. Biases in the generation and interpretation of the data are discussed and alternatives are mentioned. (auth)

  11. Diagenetic fluids evolution and genetic mechanism of tight sandstone gas reservoirs in Upper Triassic Xujiahe Formation in Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHU RuKai; ZOU CaiNeng; ZHANG Nai; WANG XueSong; CHENG Rong; LIU LiuHong; ZHOU ChuanMin; SONG LiHong

    2008-01-01

    The reservoirs of the Upper Triassic Xujiahe Formation in Sichuan Basin have the characteristics of low compositional maturity, low contents of cements and medium textural maturity.The general physical properties of the reservoirs are poor, with low porosity and low permeability, and there are only a few reservoirs with medium porosity and low permeability in local areas.Based on the diagenetic mineral association, a diagenetic sequence of cements is established: early calcites (or micrite siderites)→ first quartz overgrowth→chlorite coatings→dissolution of feldspars and debris→chlorite linings→ second quartz overgrowth (quartz widen or filled in remain intergranular pores and solution pores→ dissolution→third quartz overgrowth (quartz filled in intergranular and intragranular solution pores)→ intergrowth (ferro) calcites→dolomites→ferro (calcites) dolomites→later dissolution→veins of quartz and calcites formation.Mechanical compaction is the main factor in making the reservoirs tight in the basin, followed by the second and third quartz overgrowth.In a long-term closed system, only feldspars and some lithic fragments are dissolved by diagenetic fluids, while intergranular cements such as quartz and calcit are not dissolved and thus have little influence on the porosity of the Xujiahe Formation.This is the third factor that may have kept the sandstones of Xujiahe Formation tight finally.The hydrocarbon was extensively generated from organic materials after the second quartz overgrowth, and selectively entered favorable reservoirs to form tight sandstone gas reservoirs.

  12. X-ray diffraction analysis of mudstone from nw sudan

    International Nuclear Information System (INIS)

    This study deals with the theoretical and experimental aspects of the x-ray diffraction technique (XRD). The XRD technique is used to investigate fine structure of matter, and it is most efficient method for the determination of the mineralogical composition of rocks. The XRD technique is used also to investigate the clay mineralogical of mud-stones of the Nubian sandstones of north western Sudan. The XRD results revealed that the mud-stone samples are composed, in decreasing abundance's of kaolinite, smectite, chlorite and illite. Non-clay minerals reported include quartz, feldspars and geothite. Kaolinite dominates in most of samples with percentages ranging between 78-96%. Smectite comes second in abundance and ranges between 10-24%, followed by chlorite and illite which showed the lowest abundance's. The dominance of kaolinite over smectite indicates that intense chemical weathering and leaching occurred under warm humid climate interrupted by dry periods. Most probably these clay minerals were produced by inheritance and partly by neo formation. The variation of the chemical composition of these mud stones is due basically to differences in clay mineralogy which was controlled by source rock geology, weathering physicochemical behavior of elements, local environment and climatic condition in the past. (Author)

  13. Carbonate cementation as related to the diagenesis of clay in a mixed siliciclastic-carbonate system: Examples from the Centerfield biostrome, east central Pennsylvania

    Energy Technology Data Exchange (ETDEWEB)

    Burns, C.D. (Univ. of North Carolina, Chapel Hill, NC (United States))

    1994-03-01

    The Middle Devonian Mahantango Formation consists of siliciclastic and mixed carbonate-siliciclastic sediment packages that pulse in and out of the stratigraphy. The formation crops out in several places throughout the folded rocks of eastern Pennsylvania and Maryland. The Centerfield Member is one of the mixed siliciclastic-carbonate packages in the Mahantango Fm. This member crops out in east central Pennsylvania. The Centerfield Mbr. has been interpreted as a series of biostromes and contain abundant rugosan corals, crinoids, bryozoans, and brachiopods. The biostromes have undergone a complex diagenetic history. Illite, smectite, chlorite and muscovite have been found with the use of powder x-ray diffraction and petrographic analysis. The smectite and some of the illite are depositional clays, while, the remaining illite, chlorite and muscovite represent recrystallization of the depositional clays. There are six phases of cement in the biostrome. The paragenetic sequence of the cements is as follows: non-ferroan low magnesian calcite (LMC), intermediate ferroan LMC, ferroan LMC, non-ferroan dolomite, ferroan baroque dolomite, and quartz cement in the form of chert and blocky cement. Staining shows that the iron content of the cement changes within individual crystals and between cement phases. Preliminary data suggest that the cements may be directly related to the steady release of ions during the diagenesis of the surrounding clays in the shale.

  14. Mineralogy of Holocene Sediments from the Southwestern Black Sea Shelf (Turkey) in Relation to Provenance, Sea-level and Current Regimes

    Institute of Scientific and Technical Information of China (English)

    Emel BAYHAN; Mustafa ERG(I)N; Abidin TEMEL; Seref KESK(I)N

    2005-01-01

    Grain size and mineral composition of core sediments were used to investigate influences of various terrestrial and marine conditions,which have prevailed on the southwestern Black Sea shelf during the Holocene.Siliciclastic mud with small amounts of sand and gravel from nearby coastal hinterland is the principal sediment type,whereas sediments deposited near the shelf edge and the (I)stanbul Strait and off the Duru Lake (a paleo-river mouth)constitued large quantities of sand and gravel of both biogenic and terrigenic origin.Variable amounts of aragonite,1 nm-micas,quartz,feldspars,calcite and dolomite constitute the dominant non-clay minerals in bulk sediments.The clay mineral assemblage in the < 2 μm fraction is made up of smectite,illite,kaolinite and chlorite.Aragonite and calcite are mainly derived from benthic accumulations,whereas feldspars (mainly plagioclase) and smectite reflect magmaticvolcanic provenance and the distribution of 1 nm-micas and chlorite correlate with nearby metamorphic sources onland.Nevertheless,grain size and mineral distribution generally indicate a combination of effects of wind and wave climate,longshore and offshore cyclonic currents,changing sea-level stands and nearby source rock and morphological conditions.It is also suggested that at least part of clay minerals could be derived from the northwesterly Danube River input.

  15. SEM/EDS characterisation of dusty deposits in precipitation and assessment of their origin

    Directory of Open Access Journals (Sweden)

    Miloš Miler

    2014-07-01

    Full Text Available Detailed scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS analysis of dusty material in rainfall residue, deposited and collected on February 19th 2014 in Ljubljana, was carried out with the intention to characterise it according to its chemical and mineral composition and to assess its origin. The material consists of poorly sorted and sharp-edged particles of mostly very fine-grained silt and clay fractions, which is consistent with long-range aerial transport. Particles are represented by illite, chlorite and kaolinite group clay minerals, quartz, feldspars, carbonates, accessory minerals and secondary Fe-oxy-hydroxide minerals. Quantities of minerals and illite/ kaolinite ratio (4.5 correspond to dusts in rainfall residues originating from Moroccan Atlas, while chlorite/kaolinite ratio (2.8 agrees better with dust from central Libya. The element ratios Al/Si, Ca/Al, K/Ca, Mg/Al, Fe/Al and (Ca+Mg/Fe in the studied dusty deposit are in good agreement with ratios in dusts from rainfall residues originating from Morocco and northern Mauritania. This was also confirmed by the trajectories of cloud movement that caused precipitation with dusty deposit, although the back trajectory HYSPLIT simulation of air masses indicated northern Mauritania, central Niger, southern Algeria, southwestern and central Libya as the most possible source regions.

  16. Palevye (pale) soils of Central Yakutia: Genetic specificity, properties, and classification

    Science.gov (United States)

    Desyatkin, R. V.; Lesovaya, S. N.; Okoneshnikova, M. V.; Zaitseva, T. S.

    2011-12-01

    Permafrost-affected palevye (pale) soils of Central Yakutia are developed from mantle calcareous deposits of different textures and are characterized by the common mica-chloritic association of clay minerals with a higher content of chlorite in comparison with the soils developed from mantle loams and loess-like loams in the European part of Russia. In the pale soils, the distribution of clay minerals in the profile has an even pattern in the loamy variants and a differentiated pattern typical of podzols in the loamy sandy variants. Data on the chemical extracts and Mössbauer spectroscopy indicate that the iron in the pale soils is mainly fixed in silicate minerals. The content of nonsilicate iron represented by the amorphous and weakly crystallized compounds in the pale soils is relatively low. The humus-accumulative horizon in these soils is close to the gray-humus (soddy) AY horizon according to its acid-base characteristics (the soil pH and the degree of base saturation) despite the presence of exchangeable sodium and the shallow occurrence of the calcareous horizon.

  17. Petrology of metabasites in the south of Arousan, northeastern Isfahan province

    Directory of Open Access Journals (Sweden)

    Fereshteh Bayat

    2012-10-01

    Full Text Available Metagabbro, metadiabase and metabasalt of the Chah Palang and Me'raji mountains associated with Lower Paleozoic metamorphites are situated in the south of Arousan. Metabasites of these areas are relatively similar in terms of mineralogy and geochemical characteristics. Rock-forming minerals of the Me'raji metabasites are feldspar, amphibole, biotite, sphene, epidote, chlorite ± calcite. Metagabbro and metadiabase of the Chah Palang area are similar to the Me'raji metabasites in mineralogy and geochemistry. Volcanic rocks are overlain by metagabbros and consist of plagioclase, biotite, sphene, sanidine, chlorite, epidote and iron oxides. The rigid dykes, which are found in the volcanic units are associated with metagabbros and mineralogically are similar to the metavolcanics. Amphibolitic dykes are composed of amphibole, plagioclase and biotite with preferred orientation. Metabasites show limited range of differentiation. Me'raji metabasites are basalt and trachy-basalt in composition, whereas the Chah Palang ones present basalt and trachy-basalt composition. Similar to metabasites of the other parts of Iran, the studied basic rocks demonstrate alkaline to transitional chemical characteristic and are formed in an extensional environment by low-degree partial melting of a garnet-spinel peridotite. Metamorphic episodes have changed the studied rocks to amphibolite and greenschist, but the primitive igneous textures are preserved.

  18. Provenance and depositional age of metavolcano-sedimentary sequences of the Santa Terezinha de Goias, based on Sm-Nd and U-Pb zircon single grain; Proveniencia e idade deposicional de sequencias metavulcano-sedimentares da regiao de Santa Terezinha de Goias, baseada em dados isotopicos Sm-Nd e U-Pb em monocristal de zircao

    Energy Technology Data Exchange (ETDEWEB)

    Dantas, Ellton Luiz; Jost, Hardy; Fuck, Reinhardt A.; Brod, Jose Afonso; Pimentel, Marcio Martins; Meneses, Paulo Roberto [Brasilia Univ., DF (Brazil). Inst. de Geociencias]. E-mail: elton@unb.br

    2001-09-01

    Supracrustal rocks of the Santa Terezinha de Goias region, Central Brazil, presumably represent a southern extension of the Mara Rosa magmatic arc tectonically juxtaposed to Archean terrains and consist of a meta volcanic unit and a meta sedimentary unit. The aim of the paper is to present and discuss the first U-Pb and Sm-Nd data of rocks belonging to both units of that region. U-Pb data of zircons from a felsic meta volcanic rock inter layered with chlorite-rich schists (metandesites?) yield a concordant age of of 660 My, while the Sm-Nd model age of a variety of chlorite-schists indicate a juvenile age between 1.1 and 1.3 Ga. These data indicate that the meta volcanic rocks are Neo proterozoic in age and may be correlated with rocks of the Mara Rosa magmatic arc. On the other hand, the prevailing provenance of rocks belonging to the meta sedimentary unit indicate a Paleoproterozoic, or older, source. Thus, the deposition of both units are explained by means of the erosion of source-areas of variable age. (author)

  19. Chemical modification of cellulose extracted from sugarcane bagasse: Preparation of hydroxyethyl cellulose

    Directory of Open Access Journals (Sweden)

    E.S. Abdel-Halim

    2014-07-01

    Full Text Available Cellulose was extracted from sugarcane bagasse by alkaline extraction with sodium hydroxide followed by delignification/bleaching using sodium chlorite/hexamethylenetetramine system. Factors affecting extraction process, including sodium hydroxide concentration, hexamethylenetetramine concentration and temperature were studied and optimum conditions for alkaline extraction were found to be boiling finely ground bagasse under reflux in 1 N sodium hydroxide solution and then carrying out the delignification/bleaching treatment at 95 °C using 5 g/l sodium chlorite together with 0.02 g/l hexamethylenetetramine. The extracted cellulose was used in the preparation of hydroxyethyl cellulose through reaction with ethylene oxide in alkaline medium. Factors affecting the hydroxyethylation reaction, like sodium hydroxide concentration during the alkali formation step, ethylene oxide concentration, reaction temperature and reaction duration were studied. Optimum conditions for hydroxyethylation reaction were using 20% NaOH solution and 200% ethylene oxide (based on weight of cellulose, carrying out the reaction at 100 °C for 60 min.

  20. Characteristics and genesis of clay minerals in the northern margin of the Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    Wang Linlin; Jiang Bo; Peng Dehua; Yin Chengming; Zeng Chunlin

    2011-01-01

    In order to develop appropriate reservoir protection measures in the northern margin of the Qaidam Basin and improve its oil and gas recovery efficiency, characteristics of clay minerals from eleven clay rock samples from the northern margin of the Qaidam Basin were investigated using X-ray diffraction analysis, the Scanning Electron Microscope (SEM) and energy spectrum analysis. Clay mineral composition and distribution characteristics of the main hydrocarbon reservoirs, I.e., from the Jurassic and Paleogene-Neogene, were explored. We analyzed the main factors which affected these attributes. The results show that the major clay minerals in the northern margin are chlorite, kaolinite, illite, smectite and illite/smectite inter-stratified minerals, Illite is the most widely spread clay mineral in this area.Chlorite is mainly found in the entire Neogene and in shallow horizons of the Paleogene. Smectite is enriched in the shallow Paleogene-Neogene. There are large amounts of kaolinite and illite/smectite inter-stratified minerals in the Jurassic. The major factors affecting the different development of clay minerals in the region are properties of parent rocks, paleoclimate and paleowater media conditions,diagenesis transformation, tectonic and terrain conditions.

  1. Tectonic hydrothermal gold mineralisation in the outboard zone of the Southern Alps, New Zealand

    International Nuclear Information System (INIS)

    Gold-bearing veins cut a belt of low-grade (pumpellyite-actinolite/greenschist facies) schist in the Ben Ohau Range to the east of the Main Divide, in the outboard zone of the Southern Alps continental collisional zone, New Zealand. The schist has been exposed along the currently active Ostler Fault system, which has had c. 5 km of reverse motion since the Pliocene. The veins consist of quartz, ankerite, calcite, chlorite, and pyrite, with minor chalcopyrite and galena. Hydrothermal chlorite contains about 490 ppm Zn, and the gold contains 3-5 wt% Ag. Hydrothermal alteration of host rock is minor apart from Sr enrichment (up to four times background). Fluid inclusions in quartz are aqueous with minor dissolved CO2 and salts (18O = +10 to +14; δ13C = -6 to -10 per thousand) are similar to data from economic metamorphogenic Au deposits of the nearby Otago Schist, but minor meteoric incursion may have occurred. Isotopic data are also similar to veins formed in the inboard zone of the Southern Alps orogen. The Ben Ohau veins demonstrate that gold can be concentrated in low-grade schists distant from the most active part of the hydrothermal system driven by continental collision. (author). 45 refs., 6 figs., 3 tabs

  2. Distribution of clay minerals in marine sediments off Chennai, Bay of Bengal, India:Indicators of sediment sources and transport processes

    Institute of Scientific and Technical Information of China (English)

    Subramanian VEERASINGAM; Ramdoss VENKATACHALAPATHY; Thirunavukkarasu RAMKUMAR

    2014-01-01

    Clay mineralogy, texture size and statistical analyses were carried out on surface sediments from the continental shelf of Chennai, Bay of Bengal, India. The purpose of this study is to characterize the clay mineral distribution and its relation to the hydrodynamics off Chennai to identify the sources and transport pathways of the marine sediments. Characterization of clay minerals in coastal sediments by Fourier Transform Infrared (FTIR) spectroscopy has provided the association of quartz, feldspar, kaolinite, chlorite, illite and iron oxides (magnetite and hematite) derived from river catchments and coastal erosion. Kaolinite, chlorite, illite, iron oxides, and organic matter are the dominant minerals in Cooum, and Adayar region. High quartz and feldspar zones were identified in Marina, which are being confined the sand zone and paralleling the coast. The strong relationships among the wave energy density, sand, quartz and carbonate revealed that wave induced littoral drift system play a dominant role in transportation and deposition of sediments in the Chennai coast. The sediment texture and minerals data are in agreement well with the previous results of hydrodynamics and littoral drift models in this region. Multivariate statistical analyses (correlation, cluster and factor analyses) were carried out and obtained results suggested that clay minerals and organic matter are trapped in silt and clay particles, whereas quartz, feldspar and carbonate are associated with sand particles. Results of sediment sources and transport processes from this study will be useful to predict the fate of the pollutants released from land or the potential change in sediment delivery to coastal areas.

  3. Experimental research on hydrophilic characteristics of natural soft rock at high stress state

    Institute of Scientific and Technical Information of China (English)

    Guo Hongyun; Lei Xiangyang; Zhang Yumei; Yang Guoxing; Niu Zhang

    2015-01-01

    In order to study features of rock–water interaction, a self-developed experimental system called Intelligent Testing System for Water Absorption in Deep Soft Rocks (ITSWADSR) was utilized to analyze the hydrophilic behaviors of natural soft rock at high stress state. Combining X-ray diffraction and mer-cury injection test, main influencing factors on hydrophilic characteristics were studied. According to the results, it could be concluded as the following:(1) the effective porosity, and the content of illite, illite/smectite formation (S=5%) and kaolinite have positive correlation with the water absorption capacity of rock;meanwhile, the initial moisture content, fractal dimension of effective pores, illite/smectite forma-tion (S=30%) and chlorite present negative correlation; (2) among the positive factors, the ascending order is kaolinite, illite/smectite formation (S=5%) and illite;(3) the descending order among the nega-tive factors are chlorite, illite/smectite formation (S=30%) and fractal dimension of the effective pores;(4) influence of effective porosity on the pressurized water absorbing capacity of rock is minimal, while it is maximal in the process of no pressurized water absorption.

  4. Characteristics of fracture in the Takinoue (Kakkonda) goethermal area, iwate prefecture

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, H.; Sato, K.; Miyazaki, S.; Chiba, Y.

    1984-09-01

    Structural contour maps in the Takinoue geothermal area have been made by using data on net slips of faults and fixed-points of bedding planes as well as on strikes and dips of bedding planes. From the relation between the contour maps and distribution of fractures, characteristics of fractures in this area can be pointed out as follows: (1) fractures oblique to the bedding planes caused by flexural bedding are located at the east flank of anticlinal structure; (2) extension of fractures occurred during the period of buildup operation of production wells has been detected by acceleration-sense long-distance AE measurement equipment. Location of determined AE sources coincide fairly well with fractured layers in the Tertiary formations. The result of AE measurements showed that the newly-made fractures extended along the pre-existing faults planes and horizontal fractures; (3) the result of x-ray analysis of samples collected from 11 production wells showed that aureole of rock alteration can be divided into three subzones: chlorite subzone, laumontite subzone and gypsum subzone. Among them, the gypsum subzone is distributed along faults, then, iron-poor chlorite subzone seems to be formed in the formation with high permeability in the process of hydrothermal activity; and (4) well KD-5 drilled into deeper portion of asymmetric anticline produced much amount of geothermal steam which is supplied through vertical fracture zone with fluid temperature higher than formation temperature.

  5. Genesis of the low-permeability reservoir bed of upper Triassic Xujiahe Formation in Xinchang gas field,western Sichuan Depression

    Institute of Scientific and Technical Information of China (English)

    Xu Zhangyou; Zhang Xiaoyu; Wu Shenghe; Zhao Yan

    2008-01-01

    The genesis of a reservoir is a result of the combined action of deposition,diagenesis,tectonic reworking,and interaction of rock and fluid and the evolutionary environment.We discuss the genetic and evolution mechanism of a low-permeability reservoir bed of the Xujiahe Formation in the western Sichuan Depression on the basis of the study of diagenesis,diagenetic reservoir facies and the diagenetic evolution sequence.The research indicated that this reservoir bed can be divided into five types of diagenetic reservoir facies,namely strong dissolution,chlorite-lined intergranular pores,compaction and pressure solution,carbonate cementation and secondary quartz increase.There are,however,just two diagenetic reservoir facies which provide low-permeability reservoir beds,namely strong dissolution and chlorite-lined intergranular pores.We also analyzed their diagenetic evolution sequences and the origin of the low-permeability reservoir bed.Besides,it was also indicated that the composition and structure of sandstones,types of sedimentary microfacies,diagenesis history as well as the tectonic reworking in later periods are the main factors controlling the formation of the low-permeability reservoir bed.The above mentioned factors establish the foundation for the forecasting the distribution of high quality reservoir beds.

  6. A Study on Damage to PLA Knitted Fabrics During Scouring and Bleaching

    Directory of Open Access Journals (Sweden)

    Baig Gulzar A.

    2014-09-01

    Full Text Available Ingeo® PLA (polylactic acid knitted fabric was scoured through an exhaust technique. The scouring was carried out with sodium carbonate in the presence of a detergent at various concentrations and temperatures. The scoured fabric was bleached with various oxidative bleaching agents. Bleaching was carried out with hydrogen peroxide, sodium chlorite and sodium hypochlorite. Hydrogen peroxide was applied by exhaust and cold pad batch (CPB techniques. It was observed that during scouring PLA fabric was degraded at high alkali concentrations and processing temperatures. The scouring temperature above 60ºC proved to be deleterious due to the scouring solution penetrating into the polymer structure and damaged the fiber. Sodium chlorite and sodium hypochlorite caused little damage to the mechanical properties of PLA. Hydrogen peroxide when applied by the CPB technique did not reduce strength appreciably but when applied by the exhaust technique decreased the strength significantly. SEM analysis revealed that hydrogen peroxide caused holes and slit formation in the fiber structure.

  7. Paleoproterozoic volcanic centers of the São Félix do Xingu region, Amazonian craton, Brazil: Hydrothermal alteration and metallogenetic potential

    Science.gov (United States)

    da Cruz, Raquel Souza; Fernandes, Carlos Marcello Dias; Villas, Raimundo Netuno Nobre; Juliani, Caetano; Monteiro, Lena Virgínia Soares; Lagler, Bruno; Misas, Carlos Mario Echeverri

    2016-06-01

    Geological, petrographic, scanning electron microscopy, and X-ray diffraction studies revealed hydrothermalized lithotypes evidenced by overprinted zones of potassic, propylitic, sericitic, and intermediate argillic alterations types, with pervasive and fracture-controlled styles, in Paleoproterozoic volcano-plutonic units of the São Félix do Xingu region, Amazonian craton, northern Brazil. The Sobreiro Formation presents propylitic (epidote + chlorite + carbonate + clinozoisite + sericite + quartz ± albite ± hematite ± pyrite), sericitic (sericite + quartz + carbonate), and potassic (potassic feldspar + hematite) alterations. The prehnite-pumpellyite pair that is common in geothermal fields also occurs in this unit. The Santa Rosa Formation shows mainly potassic (biotite + microcline ± magnetite), sericitic (sericite + quartz + carbonate ± chlorite ± gold), and intermediate argillic (montmorillonite + kaolinite/halloysite + illite) alterations. These findings strongly suggest the involvement of magma-sourced and meteoric fluids and draw attention to the metallogenetic potential of these volcanic units for Paleoproterozoic epithermal and rare and base metal porphyry-type mineralizations, similar to those already identified in other portions of the Amazonian craton.

  8. 3D modelling and sheath folding at the Falun pyritic Zn-Pb-Cu-(Au-Ag) sulphide deposit and implications for exploration in a 1.9 Ga ore district, Fennoscandian Shield, Sweden

    Science.gov (United States)

    Kampmann, Tobias C.; Stephens, Michael B.; Weihed, Pär

    2016-06-01

    Altered and mineralized rocks at the Falun pyritic Zn-Pb-Cu-(Au-Ag) sulphide deposit, situated in the Palaeoproterozoic Bergslagen ore district in the south-western part of the Fennoscandian Shield, have been metamorphosed at low-pressure, amphibolite-facies conditions and affected by ductile deformation. Using combined surface mapping of lithology and structure, drill core logging and microstructural work, the polyphase (D1 and D2) ductile deformation is demonstrated and a 3D model for the deposit created. Mineral associations include quartz, biotite, cordierite, anthophyllite, and minor almandine, andalusite and chlorite in silicate-rich altered rock, calcite or dolomite in marble and tremolite-actinolite or diopside-hedenbergite in skarn. The silicate minerals show varying growth patterns during the different phases of the tectonothermal evolution, with considerable static grain growth occurring between D1 and D2, and even after D2. F2 sheath folding along axes that plunge steeply to the SSE, parallel to a mineral stretching lineation and the dip direction of the S2 foliation, is suggested as a key deformation mechanism forming steeply plunging, cone- to rod-shaped mineralized bodies. This contrasts with a previous structural model invoking fold interference. A major shear zone with talc-chlorite-(quartz-biotite) mineral association separates the northern and southern structural domains at the deposit and bounds the polymetallic massive sulphides to the north.

  9. Provenance and depositional age of metavolcano-sedimentary sequences of the Santa Terezinha de Goias, based on Sm-Nd and U-Pb zircon single grain

    International Nuclear Information System (INIS)

    Supracrustal rocks of the Santa Terezinha de Goias region, Central Brazil, presumably represent a southern extension of the Mara Rosa magmatic arc tectonically juxtaposed to Archean terrains and consist of a meta volcanic unit and a meta sedimentary unit. The aim of the paper is to present and discuss the first U-Pb and Sm-Nd data of rocks belonging to both units of that region. U-Pb data of zircons from a felsic meta volcanic rock inter layered with chlorite-rich schists (metandesites?) yield a concordant age of of 660 My, while the Sm-Nd model age of a variety of chlorite-schists indicate a juvenile age between 1.1 and 1.3 Ga. These data indicate that the meta volcanic rocks are Neo proterozoic in age and may be correlated with rocks of the Mara Rosa magmatic arc. On the other hand, the prevailing provenance of rocks belonging to the meta sedimentary unit indicate a Paleoproterozoic, or older, source. Thus, the deposition of both units are explained by means of the erosion of source-areas of variable age. (author)

  10. Diagenetic fluids evolution and genetic mechanism of tight sandstone gas reservoirs in Upper Triassic Xujiahe Formation in Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The reservoirs of the Upper Triassic Xujiahe Formation in Sichuan Basin have the characteristics of low compositional maturity, low contents of cements and medium textural maturity. The general physical properties of the reservoirs are poor, with low porosity and low permeability, and there are only a few reservoirs with medium porosity and low permeability in local areas. Based on the diagenetic mineral association, a diagenetic sequence of cements is established: early calcites (or micrite siderites) →first quartz overgrowth→chlorite coatings→dissolution of feldspars and debris→chlorite linings→ second quartz overgrowth (quartz widen or filled in remain intergranular pores and solution pores)→dissolution→third quartz overgrowth (quartz filled in intergranular and intragranular solution pores)→intergrowth (ferro) calcites→dolomites→ferro (calcites) dolomites→later dissolution→veins of quartz and calcites formation. Mechanical compaction is the main factor in making the reservoirs tight in the basin, followed by the second and third quartz overgrowth. In a long-term closed system, only feld-spars and some lithic fragments are dissolved by diagenetic fluids, while intergranular cements such as quartz and calcit are not dissolved and thus have little influence on the porosity of the Xujiahe Formation. This is the third factor that may have kept the sandstones of Xujiahe Formation tight finally. The hydrocarbon was extensively generated from organic materials after the second quartz overgrowth, and selectively entered favorable reservoirs to form tight sandstone gas reservoirs.

  11. Petrographical properties of shales from Campos Basin

    Energy Technology Data Exchange (ETDEWEB)

    Rabe, Claudio; Araujo, Ewerton M.P.; Fontoura, Sergio A.B. da [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Civil. Grupo de Tecnologia e Engenharia de Petroleo (GTEP)

    2004-07-01

    This paper presents a petrographical characterization of shales from Albacora, Marlim and Marlim Sul fields (offshore Campos Basin, Brazil). The characterization program included petrography analysis of thin section of undisturbed shale samples, scanning electron microscope (SEM) images and energy dispersive spectrometry (EDS) analysis. The tests were realized with the purpose of obtaining information to observe the nature of the rock microstructure. From the results presented herein, the shales can be described as silty and calciferous. The description of the thin sections indicated that all the shale samples are very similar from the compositional and textural point of view. The samples are rich in clay minerals, that show small size grains and seem homogeneous, and carbonatic cement. The samples are constituted by calcite, quartz, kaolinite, smecite, illite, illite/smectite, kaolinite/illite/smectite, feldspar, plagioclase, dolomite, chlorite and pyrite. The samples showed a great amount of calcium, resultant from the microfossils, that covers partially the clay minerals. Pyrite is also observed as small grains disperse throughout the sample with form of agglomerated pyrite framboids, cubo-octahedral and octahedral crystals. The EDS show the presence of picks of Si, Al, Mg, K and Na particles, indicating the presence of clay minerals, calcite, pyrite and chlorite. (author)

  12. Static and fault-related alteration in the lower ocean crust, IODP Expedition 345, Hess Deep

    Science.gov (United States)

    McCaig, Andrew; Faak, Kathrin; Marks, Naomi; Nozaka, Toshio; Python, Marie; Wintsch, Robert; Harigane, Yumiko; Titarenko, Sofya

    2014-05-01

    IODP Expedition 345 drilled the first holes in the lower plutonic crust at a fast-spreading ridge, recovering primitive layered gabbros (Gillis et al 2014). Alteration can be subdivided into two series: 1) a largely static pseudomorphic alteration affecting predominantly olivine. This began in the amphibolite facies with minor secondary cinopyroxene and hornblendic amphibole replacing primary pyroxene, and sporadically developed corona textures with tremolite and chlorite replacing olivine and plagioclase respectively, but was predominantly in the greenschist and sub-greenschist facies with talc, serpentine, clay minerals,oxides andsulphides replacing olivine, and prehnite and locally other calcsilicates replacing plagioclase, commonly in micro-vein networks. Albitic plagioclase is sporadically developed, and locally zeolite and carbonate. 2) An overprinting metasomatic alteration under sub-greenschist or perhaps lowermost greenschist conditions(zeolite. This alteration is spatially related to cataclastic fault zones and macroscopic veins. Comminuted plagioclase in cataclasites is commonly completely replaced by prehnite, while chlorite may completely pseudomorph olivine, locally with textures suggesting replacement of previous secondary minerals such as talc and serpentine. Chlorite also ubiquitously occurs as patches replacing plagioclase along grain boundaries, locally associated with carbonate and amphibole needles. Metamorphosed dykes show chilled margins within the cataclasites, and are affected by cataclastic deformation. Faults, dykes and overprinting alteration are all inferred to be related to the westward propagation of Cocos-Nazca spreading that formed Hess Deep. Samples of different alteration and cataclastic domains were cut out of this section chips for isotopic analysis. 87Sr/86Sr ratios of cataclasites and dyke rocks are in the range 0.7037 - 0.7048, indicating alteration by seawater at moderate integrated fluxes. The highest values were in

  13. 四川周公山-汉王场地区峨眉山玄武岩中流体类型及活动期次%Fluid types and activities of Emeishan basalt in Zhougong mountain-Hanwang field of Sichuan Province.

    Institute of Scientific and Technical Information of China (English)

    侯明才; 王文楷; 张本健; 王维; 李秀华; 邓敏; 裴森奇; 杨毅

    2013-01-01

    来自汉王场-周公山地区周公2井和汉6井峨眉山玄武岩钻井岩心样品显示峨眉山玄武岩有:隐晶玄武岩、杏仁状玄武岩,凝灰岩,火山角砾岩,凝灰角砾岩,绿帘石岩,赤铁矿染玄武岩,红土化玄武岩和脉岩等九种岩石类型.其中发育的杏仁体成分有:赤铁矿杏仁体、绿帘石杏仁体、石英-绿泥石杏仁体、蛋白石-赤铁矿杏仁体、磁铁矿-赤铁矿杏仁体、榍石-玉髓杏仁体、绿帘石-葡萄石-绿泥石杏仁体、钛铁矿-玉髓-绿泥石-玉髓杏仁体等8种,脉体有:长石脉、赤铁矿脉、石英脉、绿帘石脉、绿泥石、榍石脉、方解石脉、玉髓-水铝英石脉、方解石-赤铁矿脉、方解石-绿泥石脉、石英-方解石脉、石英-绿帘石脉、石英-沥青脉、赤铁矿-玉髓-绿泥石脉、绿帘石-绿泥石-玉髓脉等15种.这些脉体和杏仁体形成于峨眉山玄武岩形成演化的不同阶段,喷溢期流体受岩浆原生组分影响,大气降水影响程度低,温度属高-中温,脉体包裹体盐度-温度为正相关,代表性产物为赤铁矿脉;风化期流体主要来源于大气降水,氧化作用和水解作用对脉体的发育产生了很大影响,这一时期δ13C为低-中负值,包裹体盐度、温度低,以水铝英石脉最为典型;进入埋藏期以后,上覆地层水和深部的卤水对岩石进行改造,这一时期的流体属低-中温,包裹体盐度与温度呈负相关,受有机质影响,δ13C呈高负值,以绿帘石脉最为典型.%Samples from Zhougong 2 well and Han 6 well in Zhougong mountain-Hanwang field show that the Emeishan basalt can be divided into 9 types,cryptocrystalline basalt,amygdaloidal basalt,tuff,volcanic breccia,tuff-breccia,epidosite rock,hematitedbasalt,weathered basalt and vein rock.Minerals and with their combinations such as hematite,epidote,quartz-chlorite,opalhematite,magnetite-hematite,sphene-chalcedony,epidote-prehnite-chlorite,and ilmenite-chalcedony-chlorite

  14. Fate of gold and base metals during metamorphic devolatilization of a pelite

    Science.gov (United States)

    Zhong, Richen; Brugger, Joël; Tomkins, Andrew G.; Chen, Yanjing; Li, Wenbo

    2015-12-01

    Scavenging of gold during metamorphic devolatilization is a widely accepted model for fluid and metal sourcing in orogenic gold deposits. In order to further constrain this process and quantify the capacity of autogenous fluids to release metals from pelites, we investigated the behaviors of S, Au, As, Cu, Pb, and Zn during pelite metamorphic devolatilization using thermodynamic modeling within the Al-As-Au-Cl-Cu-Fe-H-K-Mg-Na-O-Pb-S-Si-Ti-Zn system over a P-T range of 350-650 °C and 0.8-5 kbar. The model revealed that S, Au and base metals are predominantly released via partitioning into the fluid phase during reactions that liberate H2O: the dehydration of chlorite and muscovite, and to a lesser extent, the replacement of pyrite by pyrrhotite. Negligible sulfur is liberated during the pyrite-pyrrhotite transition, because the excess sulfur reacts with Fe in chlorite and muscovite to form pyrrhotite. The sulfidation of chlorite/muscovite releases water, so that a significant amount of Au can be liberated from S-rich pelites at the pyrite to pyrrhotite transition: up to 0.5 ppb Au (as a proportion of bulk rock) can be stripped from a pelite containing 1 wt.% sulfur, whereas only trace amounts of base metals can be mobilized under these conditions. Chlorite dehydration is the most important process in metal extraction; up to 2 ppb Au, 1.5 ppm Cu, 1 ppm Pb and 2 ppm Zn (as proportions of bulk rock) can be extracted from a pelite by autogenous fluids upon crossing the greenschist-amphibolite facies boundary. In comparison, an average pelite contains ∼3 ppb Au, indicating that most Au within an average pelite can be scavenged as a result of the breakdown of chlorite. Prograde metamorphism is an efficient mechanism for generating Au-bearing ore fluids: most Au can be extracted during chlorite dehydration from a source rock of average pelitic composition. In contrast, only a small portion of base metals can be released in autogenous fluids, and therefore only minor

  15. Modelling Iron-Bentonite Interactions

    Science.gov (United States)

    Watson, C.; Savage, D.; Benbow, S.; Wilson, J.

    2009-04-01

    The presence of both iron canisters and bentonitic clay in some engineered barrier system (EBS) designs for the geological disposal of high-level radioactive wastes creates the potential for chemical interactions which may impact upon the long-term performance of the clay as a barrier to radionuclide migration. Flooding of potential radionuclide sorption sites on the clay by ferrous ions and conversion of clay to non-swelling sheet silicates (e.g. berthierine) are two possible outcomes deleterious to long-term performance. Laboratory experimental studies of the corrosion of iron in clay show that corrosion product layers are generally thin ( 250 °C) are dominated by chlorite, whereas lower temperatures produce berthierine, odinite, cronstedtite, or Fe-rich smectite. Unfortunately, the inevitable short-term nature of laboratory experimental studies introduces issues of metastability and kinetics. The sequential formation in time of minerals in natural systems often produces the formation of phases not predicted by equilibrium thermodynamics. Evidence from analogous natural systems suggests that the sequence of alteration of clay by Fe-rich fluids will proceed via an Ostwald step sequence. The computer code, QPAC, has been modified to incorporate processes of nucleation, growth, precursor cannibalisation, and Ostwald ripening to address the issues of the slow growth of bentonite alteration products. This, together with inclusion of processes of iron corrosion and diffusion, has enabled investigation of a representative model of the alteration of bentonite in a typical EBS environment. Simulations with fixed mineral surface areas show that berthierine dominates the solid product assemblage, with siderite replacing it at simulation times greater than 10 000 years. Simulations with time-dependent mineral surface areas show a sequence of solid alteration products, described by: magnetite -> cronstedtite -> berthierine -> chlorite. Using plausible estimates of mineral

  16. Fluid-induced Blueschist Preservation on Syros, Cyclades, Southern Greece

    Science.gov (United States)

    Kleine, B. I.; Huet, B.; Skelton, A. D. L.

    2012-04-01

    Local examples of preservation of high-pressure, low-temperature (HP-LT) mineral assemblages within retrograde metamorphosed greenschist are recorded from the Cyclades, Greece. Several models have been proposed to explain the preservation of HP-LT rocks in these areas. On Sifnos, a capping effect of impermeable marble units below the preserved blueschists caused diversion of the upward, cross-layer infiltration of retrograde fluids [1]. On Tinos, blueschist preservation occurred due to retrograde fluid flow channelization along lithological contacts with high flux rates [2]. HP-LT minerals were preserved in regions adjacent to these contacts where fluid fluxes were smaller. We propose a different mechanism of blueschist preservation based on observations from a costal section near Fabrika on Syros. At this locality a high strain zone cuts through a retrograde greenschist. Along the fault a dark blue halo occurs within the greenschist. Whole rock analyses along a profile from the fault into the greenschist show that only the areas directly adjacent to the deformation zone show chemical evidence of metasomatism, whereas the areas further away are chemically similar to greenschist. Point counting of 1000 evenly spaced points in thin sections of the profile shows a clear blueschist to greenschist transition with a blueschist mineral assemblage (glaucophane+phengite+calcite) nearer to the metasomatic zone and a typical greenschist mineral assemblage (epidote+chlorite+albite) farther away. We propose the following model to explain preservation of HP-LT mineral assemblage in this locality. During retrograde metamorphism a water-rich fluid infiltrated the blueschist rock from below. This occurred close to the brittle-ductile transition. This fluid caused a reaction front to propagate into the overlying blueschist at which its mineral assemblage glaucophane+phengite+calcite was replaced by the greenschist mineral assemblage epidote+albite+chlorite. Upwards-flowing fluid

  17. Paleofluid Flow in the Upper Crust: A Study Case from the Atacama Fault System

    Science.gov (United States)

    Gomila, R.; Arancibia, G.; Cembrano, J. M.; Mitchell, T. M.; Faulkner, D. R.; Jensen Siles, E.

    2014-12-01

    Fault zones and fault-related permeability structures have long been recognized to play a first-order role on fluid flow migration through the crust. However, the nature of the spatial relationship between fault zones and fluid-flow and the evolution of such permeability structures in terms of paleofluid flow quantification is less well understood. This work presents a microfracture analysis aimed to unravel the nature of the fault plumbing system and estimate paleo permeability parameters within the Jorgillo Fault (JF), a subvertical strike-slip fault exposed in the Atacama Fault System in northern Chile. The JF is a ca. 18 km long, NNW striking strike-slip fault with sinistral horizontal separation of ca. 4 km. The JF juxtaposes orthogranulites to the west (JFW) with gabbros to the east side (JFE) wherea 200 m fault-perpendicular transect was mapped and sampled. The fault core consists of ca. 1 m cataclasite bounded by fault gouge zones of ca. 80 cm to the west and 30 cm to the east. A ca. 50 m wide symmetrical damage zone can be observed at field scale. The damage zone in the JFW is characterized by shear fractures and cataclasites whereas the JFE consists of open fractures and veins. The JFW microfracture analysis reveal mm-wide cataclasitic/ultracataclasitic bands orientated subparallel to the JF, calcite veins in a T-fracture orientation, and minor polydirectional chlorite veins. In the JFE, 1-20 mm wide chlorite, quartz-epidote and quartz-calcite veins, can be observed. Chlorite conjugate veins show syntaxial growth textures suggesting dilatational fracturing. Microfractures distribution show shear fractures distributed only in JFW while open fractures are mainly in the JFE. Using models off paleofluid flow, cumulative permeability (i.e. permeability due to all types of microfractures present in the samples) was estimated to range from 2.761x10-11 to 4.89x10-9 m2 on the JFE, and 8.04x10-12 to 4.39x10-8 m2 on the JFW.

  18. Characteristics of Clay Minerals in the Northern South China Sea and Its Implications for Evolution of East Asian Monsoon since Miocene

    Institute of Scientific and Technical Information of China (English)

    Wan Shiming; Li Anchun; Xu Kehui; Yin Xueming

    2008-01-01

    Clay mineral assemblages, crystallinity, chemistry, and micromorphology of clay particles in sediments from ODP Site 1146 in the northern South China Sea (SCS) were analyzed, and used to trace sediment sources and obtain proxy records of the past changes in the East Asian monsoon climate since the Miocene, based on a multi-approach, including X-ray diffraction (XRD) and scanning electron microscopy combined with energy dispersive X-ray spectrometry (SEM-EDS). Clay minerals consist mainly of illite and smectite, with associated chlorite and kaolinite. The illite at ODP Site 1146 has very well-to-well crystallinity, and smectite has moderate-to-poor crystallinity. In SEM the smectite particles at ODP Site 1146 often appear cauliflower-like, a typical micromorphology of volcanic smecites. The smectite at ODP Site 1146 is relatively rich in Si element, but poor in Fe, very similar to the smectite from the West Philippine Sea. In contrast, the chemical composition of illite at ODP Site 1146 has no obvious differences from those of the Loess plateau, Yellow River, Yangtze River, and Pearl River. A further study on sediment source indicates that smectite originates mainly from Luzon, kaolinite from the Pearl River, and illite and chlorite from the Pearl River, Taiwan and/or the Yangtze River. The clay mineral assemblages at ODP Site 1146 were not only controlled by continental eathering regimes surrounding the SCS, but also by the changing strength of the transport processes. The ratios of (illite+chlorite)/smectite at ODP Site 1146 were adopted as proxies for the East Asian monsoon evolution. Relatively higher ratios reflect strongly intensified winter monsoon relative to summer monsoon, in contrast, lower ratios indicate a strengthened summer monsoon relative to winter monsoon. The consistent variation of this clay proxy from those of Loess plateau, eolian deposition in the North Pacific, planktonic, benthic foraminifera, and black carbon in the SCS since 20 Ma shows

  19. Climatic control of sediment transport from the Himalayas to the proximal NE Bengal Fan during the last glacial-interglacial cycle

    Science.gov (United States)

    Joussain, Ronan; Colin, Christophe; Liu, Zhifei; Meynadier, Laure; Fournier, Léa; Fauquembergue, Kelly; Zaragosi, Sébastien; Schmidt, Frédéric; Rojas, Virginia; Bassinot, Franck

    2016-09-01

    Clay mineralogy, siliciclastic grain-size, major elements, 87Sr/86Sr, and εNd analyses of deep-sea sediments cored in the north-eastern Bay of Bengal are used to reconstruct evolution of detrital sources and sediment transport to the proximal part of the Bengal deep-sea fan during the last climatic cycle. εNd values (-13.3 to -9.7) and 87Sr/86Sr ratios (0.721-0.733) indicate a mixture of sediments originating from the Ganges-Brahmaputra rivers and the Indo-Burman ranges. Interglacial Marine Isotopic Stages (MIS) 5 and 1 are associated with a higher contribution of sediments from the Ganges-Brahmaputra river system than is the case for glacial MIS 6, 4, 3, and 2. Siliciclasitic grain-size combined with Si/Al and Si/Fe ratios indicate coarser glacial sediments with numerous turbidite layers. Glacial turbidite layers display similar clay mineralogical compositions to hemipelagic sediments. Only few of turbidite layers (MIS 6, 4, and 2) are slightly unradiogenic (εNd -13.3), suggesting a higher contribution of Ganges-Brahmaputra river sediments. Independently of changes in the sedimentary sources, the smectite/(illite + chlorite) ratio of cores located on the NE Bengal Fan indicates higher inputs of primary minerals (illite and chlorite) from the highlands of the river basins (relief) during glacial MIS 6, 4, 3, and 2 and an increased contribution of pedogenic minerals (smectite and kaolinite) during interglacial MIS 5 and 1. Maximum smectite/(illite + chlorite) ratios during the warm sub-stages of MIS 5 suggest an intensification of summer monsoon rainfall associated with higher rates of physical erosion of the Indo-Gangetic flood-plain and/or dominant summer hydrological conditions transporting a higher proportion of sediments deriving from the Ganges-Brahmaputra rivers to the NE Bengal Fan. In addition, a higher production of smectite in soils of the Indo-Gangetic flood-plain during periods of intensification of monsoon rainfall cannot be excluded.

  20. Fluid-related inclusions in Alpine high-pressure peridotite reveal trace element recycling during subduction-zone dehydration of serpentinized mantle (Cima di Gagnone, Swiss Alps)

    Science.gov (United States)

    Scambelluri, Marco; Pettke, Thomas; Cannaò, Enrico

    2015-11-01

    Serpentinites release at sub-arc depths volatiles and several fluid-mobile trace elements found in arc magmas. Constraining element uptake in these rocks and defining the trace element composition of fluids released upon serpentinite dehydration can improve our understanding of mass transfer across subduction zones and to volcanic arcs. The eclogite-facies garnet metaperidotite and chlorite harzburgite bodies embedded in paragneiss of the subduction melange from Cima di Gagnone derive from serpentinized peridotite protoliths and are unique examples of ultramafic rocks that experienced subduction metasomatism and devolatilization. In these rocks, metamorphic olivine and garnet trap polyphase inclusions representing the fluid released during high-pressure breakdown of antigorite and chlorite. Combining major element mapping and laser-ablation ICP-MS bulk inclusion analysis, we characterize the mineral content of polyphase inclusions and quantify the fluid composition. Silicates, Cl-bearing phases, sulphides, carbonates, and oxides document post-entrapment mineral growth in the inclusions starting immediately after fluid entrapment. Compositional data reveal the presence of two different fluid types. The first (type A) records a fluid prominently enriched in fluid-mobile elements, with Cl, Cs, Pb, As, Sb concentrations up to 103 PM (primitive mantle), ∼102 PM Tl, Ba, while Rb, B, Sr, Li, U concentrations are of the order of 101 PM, and alkalis are ∼2 PM. The second fluid (type B) has considerably lower fluid-mobile element enrichments, but its enrichment patterns are comparable to type A fluid. Our data reveal multistage fluid uptake in these peridotite bodies, including selective element enrichment during seafloor alteration, followed by fluid-rock interaction along with subduction metamorphism in the plate interface melange. Here, infiltration of sediment-equilibrated fluid produced significant enrichment of the serpentinites in As, Sb, B, Pb, an enriched trace

  1. Hydrothermal alteration styles in ancient and modern orogenic gold deposits, New Zealand

    International Nuclear Information System (INIS)

    Orogenic hydrothermal systems in the South Island of New Zealand were active during Mesozoic and late Cenozoic collisional deformation and metamorphism of greywacke/schist terranes. Observations on the currently active mountain-building environment yield insights on processes occurring in the upper 5-15 km of the crust, and observations on an adjacent lithologically identical exhumed ancient mountain belt provide information on processes at 10-20 km in the crust. Hydrothermal fluids were mainly derived from metamorphic dehydration reactions and/or circulating topographically driven meteoric water in these mountain belts. Three geochemically and mineralogically different types of hydrothermal alteration and vein mineralisation occurred in these orogenic belts, and gold enrichment (locally economic) occurred in some examples of each of these three types. The first type of alteration involved fluids that were in or near chemical equilibrium with their greenschist facies host rocks. Fluid flow was controlled by discontinuous fractures, and by microshears and grain boundaries in host rocks, in zones from metres to hundreds of metres thick. Vein and alteration mineralogy was similar to that of the host rocks, and included calcite and chlorite. The second type of alteration occurred where the fluids were in distinct disequilibrium with the host rocks. Fracture permeability was important for fluid flow, but abundant host rock alteration occurred as well. The alteration zones were characterised by decomposition of chlorite and replacement by ankeritic carbonate in zones up to tens of metres thick. The mineralising fluid was deep-sourced and initially rock-equilibrated, with some meteoric input. The third type of mineralisation was controlled almost exclusively by fracture permeability, and host rock alteration was minor (centimetre scale). This mineralisation type commonly involved calcite and chlorite as vein and alteration minerals, and mineralisation fluids had a major

  2. 鄂尔多斯盆地罗庞塬地区长8储层成岩相及其对物性的控制作用%Diagenetic facies and its control over physical property of Chang 8 reservoir in Luopangyuan area of Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    张彬; 屈红军; 李敏; 杨欢; 王力; 郑艳荣

    2013-01-01

    罗庞塬地区长8油层组是定边油田重要的产油层段之一,但总体研究程度较低.文中综合利用物性分析、铸体薄片、扫描电镜、压汞等资料对罗庞塬地区的成岩相及其对物性的影响做了详细研究,得出以下结论:研究区长8油层组主要发育四种成岩相,绿泥石环边胶结—长石溶蚀相、长石溶蚀—铁方解石胶结相、铁方解石连晶胶结相和泥质胶结压实相.储层的物性分布规律明显受成岩相控制,绿泥石环边胶结—长石溶蚀相区储层物性最好,为最有利储集层发育的相带;长石溶蚀—铁方解石胶结相区储层物性稍差,为较有利储集层发育的相带.%Chang 8 oil-bearing layer in Luopangyuan area is one of the important oil producing intervals in Dingbian oil field, but is in low exploration extent. Based on data of physical property analyses, cast-slice, SEM analyses and mercury injection, the paper investigated diagenetic facies in Luopangyuan area and its control over physical property. Draw the following conclusions; the Chang 8 oil-bearing layer of the study area was divided into four diagenetic types of facies combination, including rim cementation-corrosion of chlorites, corrosion and carbonate cementation, poikilitic cementation of calcites and dense-mudstone compaction. The distribution of reservoir quality was obviously controlled by diagenetic facies. The reservoir quality of chlorite-rim cementation-corrosion belts are the best, which were proposed to be the most favorable places for reservoir development. The reservoir quality of corrosion and carbonate cementation is less than chlorite-rim cementation-corrosion belts, which is more favorable places for reservoir development.

  3. DISTRIBUTION PATTERN OF CLAY MINERALS IN SURFACE SEDIMENTS OF SOUTH YELLOW SEA AND THEIR PROVENANCE%南黄海表层沉积物黏土矿物分布及物源

    Institute of Scientific and Technical Information of China (English)

    蓝先洪; 张宪军; 刘新波; 李日辉; 张志珣

    2011-01-01

    通过对南黄海表层沉积物295个站位的黏土矿物含量分析,研究了南黄海表层沉积物黏土矿物的组合特征、分布规律及与物质来源的关系.南黄海表层沉积物中伊利石含量最高,蒙脱石和高岭石含量次之,绿泥石含量最低;黏土矿物的组合类型以伊利石-蒙脱石-高岭石-绿泥石型为主,伊利石-高岭石-蒙脱石-绿泥石型次之;南黄海表层沉积物黏土矿物主要为陆源成因,物质主要来源于黄河和长江的供给.现代黄河物质及老黄河物质主要沉积于南黄海的西部和中部;长江物质主要在南黄海的西南和中北部区域沉积,东部物质反映来自朝鲜半岛的物质对南黄海东部的作用.%The clay minerals composition of the surface sediments in the South Yellow Sea from 295 stations were studied with focus on clay assemblages and their distribution pattern as well as provenance. The research results show that illite dominates in surface sediments of the South Yellow Sea with smectite or kao-linite as the second and chlorite the lowest. The assemblage of illite-smectite-kaolinete-chlorite is the main type of the clay minerals assemblage in the area, followed by the illite-kaolinete-smectite-chlorite assemblage. Clay minerals are mainly from the Yellow River and Yangtze River. Materials from both the recent and the ancient Yellow River deposited mainly in the western, middle part of the South Yellow Sea, while the substance from the Yangtze River deposited mainly in the southwestern and southern parts. In the eastern part of the study area, an influence of the material from the Korean peninsula was observed.

  4. Unbiased isotope equilibrium factors from partial isotope exchange experiments in 3-exchange site systems

    Science.gov (United States)

    Agrinier, Pierre; Javoy, Marc

    2016-09-01

    Two methods are available in order to evaluate the equilibrium isotope fractionation factors between exchange sites or phases from partial isotope exchange experiments. The first one developed by Northrop and Clayton (1966) is designed for isotope exchanges between two exchange sites (hereafter, the N&C method), the second one from Zheng et al. (1994) is a refinement of the first one to account for a third isotope exchanging site (hereafter, the Z method). In this paper, we use a simple model of isotope kinetic exchange for a 3-exchange site system (such as hydroxysilicates where oxygen occurs as OH and non-OH groups like in muscovite, chlorite, serpentine, or water or calcite) to explore the behavior of the N&C and Z methods. We show that these two methods lead to significant biases that cannot be detected with the usual graphical tests proposed by the authors. Our model shows that biases originate because isotopes are fractionated between all these exchanging sites. Actually, we point out that the variable mobility (or exchangeability) of isotopes in and between the exchange sites only controls the amplitude of the bias, but is not essential to the production of this bias as previously suggested. Setting a priori two of the three exchange sites at isotopic equilibrium remove the bias and thus is required for future partial exchange experiments to produce accurate and unbiased extrapolated equilibrium fractionation factors. Our modeling applied to published partial oxygen isotope exchange experiments for 3-exchange site systems (the muscovite-calcite (Chacko et al., 1996), the chlorite-water (Cole and Ripley, 1998) and the serpentine-water (Saccocia et al., 2009)) shows that the extrapolated equilibrium fractionation factors (reported as 1000 ln(α)) using either the N&C or the Z methods lead to bias that may reach several δ per mil in a few cases. These problematic cases, may be because experiments were conducted at low temperature and did not reach high

  5. Rayleigh-type parametric chemical oscillation

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Shyamolina; Ray, Deb Shankar, E-mail: pcdsr@iacs.res.in [Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

    2015-09-28

    We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained Rayleigh-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions.

  6. The effects of hemicelluloses and lignin removal on water uptake behavior of hemp fibers.

    Science.gov (United States)

    Pejic, Biljana M; Kostic, Mirjana M; Skundric, Petar D; Praskalo, Jovana Z

    2008-10-01

    This study investigated the individual influences of hemicelluloses and lignin removal on the water uptake behavior of hemp fibers. Hemp fibers with different content of either hemicelluloses or lignin were obtained by chemical treatment with 17.5% sodium hydroxide or 0.7% sodium chlorite. Various tests (capillary rise method, moisture sorption, water retention power) were applied to evaluate the change in water uptake of modified hemp fibers. The obtained results show that when the content of either hemicelluloses or lignin is reduced progressively by chemical treatment, the capillary properties of hemp fibers are improved, i.e. capillary rise height of modified fibers is increased up to 2.7 times in relation to unmodified fibers. Furthermore, hemicelluloses removal increases the moisture sorption and decreases the water retention values of hemp fibers, while lignin removal decreases the moisture sorption and increases the water retention ability of hemp fibers.

  7. The differences in clay minerals between the northern and southern Chelungpu fault, Taiwan

    Science.gov (United States)

    Hashimoto, Y.

    2004-12-01

    In 1999, we obtained a detailed data about motion of fault from the Taiwan Chi-Chi earthquake. The motion represents the high frequency of acceleration and small slip distance in southern part, and low frequency of acceleration and large slip distance in the northern part. Those differences in the fault motion between the southern and northern parts are coincidence with occurrences of deformation textures of rocks which were sampled by drilling of shallow parts (a few hundreds meter) of the fault in 2000. In the southern core, a relatively strong deformation structure is preserved in total, and gouge containing fragments of pseudotachylytes and ultracataclasites is observed at the Chi-Chi- earthquake fault, which indicates that the main deformation mechanisms for the southern part of the fault was brittle. On the other hands, in the northern part, sand layer with much amount of water is found at the Chi-Chi- earthquake fault zone, and no breakage of sand grain is observed, which suggests that the deformation mechanism for northern part is independent particulate flow. The purpose of this study is to reveal the differences in clay minerals between the southern and northern part of the Chi-Chi earthquake fault. And then, we discuss about rock-fluid interaction and frictional heating characterized in seismogenic fault system. We analyzed clay minerals by X-ray diffract meter (XRD) after classification of rock types such as sandstone, alteration of sandstone and mudstone, breccia, and gouge. 1.33 micron meter of grains are obtained. Oriented sample was made. XRD analysis was conducted under following condition; 35kV, 15mA, 1 degree per minute of scan rate, and 0.02 degree of scan step. Range of 2 theta was from 2 degree to 35 degree. At first, air-dried condition of samples was measured. After that, ethylene glycol solvated samples were measured. The result represents that all samples contain smectite, illite, chlorite. No difference in components of clay mineral is

  8. Analysis of mixed-layer clay mineral structures

    Science.gov (United States)

    Bradley, W.F.

    1953-01-01

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

  9. Apports des phyllosilicates dans la différenciation entre altération hypogène et altération supergène dans le basalte triasique du Moyen Atlas (Maroc)Contribution of phyllosilicates to distinguish between hypogene alteration and weathering in Triassic basalt from Middle Atlas (Morocco)

    Science.gov (United States)

    Dekayir, Abdelilah; Danot, Michel; Allali, Nabil

    2002-09-01

    Triassic basalt of the Middle Atlas has been subject to metamorphic transformation then weathering. Occurrence in both metabasalt and saprolite of ubiquitous clay minerals, such as smectite and mixed layers chlorite-smectite, makes it difficult to distinguish between the two alteration facies and explains the interest of complementary sources of information. In the Bhallil weathering profile, petrographical and mineralogical analyses of primary igneous minerals and their alteration products coupled with Fe oxidation state determination in clay fractions allow to identify three alteration facies: ( i) metamorphic basalt, where iron occurs mainly as the ferrous form; ( ii) the lower part of saprolite, where iron is partially oxidized to its ferric form; ( iii) the upper part of saprolite, where iron is completely oxidized. To cite this article: A. Dekayir et al., C. R. Geoscience 334 (2002) 877-884.

  10. Caractérisation des paragenèses et des paléocirculations fluides dans l'indice d'or de Bleïda (Anti-Atlas, Maroc)Characterization of the paragenesis and the fluid palaeo-circulations in the gold showings of Bleida (Anti-Atlas, Morocco)

    Science.gov (United States)

    Barakat, Ahmed; Marignac, Christian; Boiron, Marie-Christine; Bouabdelli, Mohamed

    2002-01-01

    The gold showings at Bleida are hosted in Late Pan-African N50-80 °E quartz-hematite-chlorite 1 tension lenses that are related to the activity of major sinistral sub-east-west thrusts. Ores result from three superimposed stages of fluid migration. Gold occurs in microcracks offsetting the earlier minerals. Fluids evolved from COHN compositions with a saline component to boiling aqueous fluids. Pressure and temperature decreased from 50 MPa and 300 °C to less than 4 MPa and 150 °C. Thus, the gold showings at Bleida were formed in a typical geothermal (epithermal) setting, likely controlled by the Late Pan-African magmatism. To cite this article: A. Barakat et al., C. R. Geoscience 334 (2002) 35-41

  11. Le volcanisme cambrien du Maroc central : implications géodynamiquesThe Central Morocco Cambrian volcanism: geodynamic implications

    Science.gov (United States)

    Ouali, Houssa; Briand, Bernard; Bouchardon, Jean-Luc; Capiez, Paul

    2003-05-01

    In southeastern Central Morocco, the Bou-Acila volcanic complex is considered of Cambrian age. In spite of low-grade metamorphic effect, initial volcanic texture and mineralogy can be recognized and volcanic rocks are dominated by dolerites and porphyric dolerites. The initial mineralogy is composed of plagioclases, pyroxenes and dark minerals. A secondary mineral assemblage is composed of albite, epidote, chlorite and calcite. According to their immobile elements compositions, the southeastern central Morocco metavolcanites are of within-plate continental tholeiites. This volcanism and those recognized in many other areas in Morocco confirm a Cambrian extensive episode within the Gondwana supercontinent. To cite this article: H. Ouali et al., C. R. Geoscience 335 (2003).To cite this article: H. Ouali et al., C. R. Geoscience 335 (2003).

  12. Genesis of hydrothermal alterations using stable isotope geochemistry in Takestan area (Tarom zone

    Directory of Open Access Journals (Sweden)

    Batool Taghipou

    2015-12-01

    Full Text Available Hydrothermal alteration processes are extensively took place on volcanic and pyroclstics of Takestan area. Existence of abundant, deep fracturing and subvolcanic intrusions are enhanced extend hydrothermal alteration zones. The following alteration zones are determined: propylitic, argillic, advanced argillic and sillicic. There are outcropped and widespread in different size and limit. Formation of siliceous sinter, silicified tuffs with preserved primary sedimentary layering including pure mineralized alunite patches are most outstanding. Quartz, sussoritic plagioclase, chlorite, sericite and alunite are main mineral constituents in the volcanics. On the basis of geochemical data volcanic rocks are rhyolite, dacite, andesite, andesitic-basalt and basalt in composition. Acid-sulfate zone is the type of alteration in Tarom area and alunite is an index mineral of this zone. Results of 18O, D and 34S stable isotope geochemistry on altered minerals (muscovite, kaolinite and alunite, revealed that alteration fluids are magmatic in origin.

  13. Do suspended sediment and bedload move progressively from the summit to the sea along Magela Creek, northern Australia?

    Science.gov (United States)

    Erskine, W. D.; Saynor, M. J.; Turner, K.; Whiteside, T.; Boyden, J.; Evans, K. G.

    2015-03-01

    Soil erosion rates on plots of waste rock at Ranger uranium mine and basin sediment yields have been measured for over 30 years in Magela Creek in northern Australia. Soil erosion rates on chlorite schist waste rock are higher than for mica schist and weathering is also much faster. Sediment yields are low but are further reduced by sediment trapping effects of flood plains, floodouts, billabongs and extensive wetlands. Suspended sediment yields exceed bedload yields in this deeply weathered, tropical landscape, but the amount of sand transported greatly exceeds that of silt and clay. Nevertheless, sand is totally stored above the topographic base level. Longitudinal continuity of sediment transport is not maintained. As a result, suspended sediment and bedload do not move progressively from the summit to the sea along Magela Creek and lower Magela Creek wetlands trap about 90.5% of the total sediment load input.

  14. The effects of retrograde reactions and of diffusion on 39Ar-40Ar ages of micas

    DEFF Research Database (Denmark)

    Allaz, Julien; Engi, Martin; Berger, Alfons;

    2011-01-01

    Effects of metamorphic reactions occurring during decompression were explored to understand their influence on 39Ar-40Ar ages of micas. Monometamorphic metasediments from the Lepontine Alps (Switzerland) were studied. Collected samples reached lower amphibolite facies during the Barrovian....... XRD-data indicated that some mineral separates prepared for Ar-Ar stepwise heating analysis were monomineralic, whereas others were composed of two white micas (muscovite with paragonite or margarite), or biotite and chlorite. In monomineralic samples 37Ar/39Ar and 38Ar/39Ar (proportional to Ca....../K and Cl/K ratios) did not change and the resulting ages can be interpreted unambiguously. In mineral separates containing two white micas, Ca/K and Cl/K ratios were variable, reflecting non-simultaneous laboratory degassing of the two heterochemical Ar-reservoirs. These ratios were used to identify each...

  15. Experimental study of gold activation-transportation in the process of potash metasomatism-alteration ——North China platform gold deposit taken as an example

    Institute of Scientific and Technical Information of China (English)

    WANG; Yurong; HU; Shouxi

    2001-01-01

    Chemical reactions of plagioclase, biotite and their single minerals, as well as a mineral mixture of (plagioclase +biotite+quartz), with KCl and (KCl+KHCO3) solutions were carried out at 150400℃ and 5080 MPa. Experiments show that alkaline fluid promotes plagioclase’s changing into potash feldspar, while acid fluid helps plagioclase, potash feldspar and biotite alteration form chlorite and sericite. After chemical reaction the acidity-alkalinity of solutions often changes reversely. It was observed that gold dissolved from the tube wall and recrystallized on the surfaces of biotite and pyrite. Therefore the transportation and enrichment of gold are related to the elementary effect of the fluid-mineral interfaces. Fe3+-Fe2+, as an oxidition-reduction agent, and volatile components Cl? and CO2 play important roles in the reaction process.

  16. Experimental study of gold activation-transportation in the process of potash metasomatism-alteration——North China platform gold deposit taken as an example

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Chemical reactions of plagioclase, biotite and their singleminerals, as well as a mineral mixture of (plagioclase +biotite+quartz), with KCl and (KCl+KHCO3) solutions were carried out at 150400℃ and 5080 MPa. Experiments show that alkaline fluid promotes plagioclase’s changing into potash feldspar, while acid fluid helps plagioclase, potash feldspar and biotite alteration form chlorite and sericite. After chemical reaction the acidity-alkalinity of solutions often changes reversely. It was observed that gold dissolved from the tube wall and recrystallized on the surfaces of biotite and pyrite. Therefore the transportation and enrichment of gold are related to the elementary effect of the fluid-mineral interfaces. Fe3+-Fe2+, as an oxidition-reduction agent, and volatile components Cl? and CO2 play important roles in the reaction process.

  17. CHLORINE DIOXIDE BLEACHING OF SODA-ANTHRAQUINONE JUTE PULP TO A VERY HIGH BRIGHTNESS

    Directory of Open Access Journals (Sweden)

    M. Sarwar Jahan

    2010-05-01

    Full Text Available Bleaching of soda-anthraquinone jute pulp by chlorine dioxide (ClO2 was studied to reach a target brightness of above 88% for the purpose of using less bleaching chemicals. The performance of either chlorine dioxide or peroxide in the final bleaching to boost brightness was also studied. The experimental results revealed that the final brightness depended on ClO2 charge in the Do and D1 stages. The brightness reversion was lower when the final stage brightening was done by peroxide. The use of Mg(OH2 in the D1 and D2 stages improved the final brightness due to the formation of less chlorate and chlorite during the Mg(OH2- based ClO2 brightening stages. The strength properties of pulp bleached by peroxide in the final stage was slightly better than that from ClO2 as the final ClO2 bleaching stage.

  18. The blueschits from the Kopina Mt., West Sudetes, Poland - what do they tell us about accretion of the Variscides?

    Science.gov (United States)

    Majka, Jarosław; Mazur, Stanisław; Kośmińska, Karolina; Dudek, Krzysztof

    2015-04-01

    Blueschists are tracers of sutures, thus marking fossil subduction zones at convergent plate boundaries and providing important constraints on plate tectonic reconstructions. Their occurrences are scarce in the Variscan belt owing to a strong collisional overprint but just because of that each locality deserves particular attention. The Variscan blueschists must have formed during the early stage of the Variscan Orogeny and may represent a vestige of missing marginal basins fringing the Rheic Ocean at the onset of subduction. The studied rocks from the Kopina Mt. consist mainly of garnet, glaucophane, clinozoisite-epidote, chlorite-I, titanite, hematite and quartz. The original high-pressure assemblage is overprinted by later, lower pressure paragenesis, which comprises mostly Ca-amphiboles, chlorite-II, albite and K-feldspar. The latter occurs in polymineral inclusions in other phases together with albite and chlorite that are interpreted as phengite breakdown products. Garnet shows chemical compositional variation from Alm54Prp3Grs30Sps13 in the cores to Alm66Prp4Grs29Sps1 in the rims. The almandine zoning is bowl-shaped, whereas spessartine profiles show bell-shaped trends. The grossular and pyrope contents are generally constant throughout the grain. Rather gradual changes in the chemical zoning suggest a progressive, one-step garnet growth pattern. Glaucophane, although commonly well preserved, in some cases disintegrates to the albite-chlorite assemblage. The pressure-temperature (P-T) conditions were estimated using the phase equilibrium modelling in the NCKFMMnASHTO system using the PerpleX software. The compositional isopleths cross cut in the stability field of Grt+Gln+Ep+Chl+Pheng+Ttn+Hem+Q. P-T estimates indicate that the peak conditions occur at c. 14-17 kbar and 470-500°C, which corresponds to quite a low geothermal gradient in the range of 8-10°C/km. The P-T conditions estimated lie on a low temperature geotherm that is typical for a relatively

  19. The effect of non-structural components and lignin on hemicellulose extraction.

    Science.gov (United States)

    Liu, Kai-Xuan; Li, Hong-Qiang; Zhang, Jie; Zhang, Zhi-Guo; Xu, Jian

    2016-08-01

    As the important structural component of corn stover, hemicellulose could be converted into a variety of high value-added products. However, high quality hemicellulose extraction is not an easy issue. The present study aims to investigate the effects of non-structural components (NSCs) and lignin removal on alkaline extraction of hemicellulose. Although NSCs were found to have a minimal effect on hemicellulose dissolution, they affected the color values of the hemicellulose extracts. The lignin limited the hemicellulose dissolution and increased the color value by binding to hemicellulose molecules and forming lignin-carbohydrate complexes. Sodium chlorite method can remove about 90% lignin from corn stover, especially the lignin connected to hemicellulose through p-coumaric and ferulic acids. Which increased the hemicellulose dissolution ratio to 93% and reduced the color value 14-28%, but the cost is about 20% carbohydrates lost. PMID:27213576

  20. Mid amphibolite facies metamorphism of harzburgites in the Neoproterozoic Cerro Mantiqueiras Ophiolite, southernmost Brazil

    Directory of Open Access Journals (Sweden)

    HARTMANN LÉO A.

    2003-01-01

    Full Text Available Valuable information is retrieved from the integrated investigation of the field relationships, microstructure and mineral compositions of harzburgites from the Neoproterozoic Cerro Mantiqueiras Ophiolite. This important tectonic marker of the geological evolution of southernmost Brazilian Shield was thoroughly serpentinized during progressive metamorphism, because the oldest mineral assemblage is: olivine + orthopyroxene + tremolite + chlorite + chromite. This M1 was stabilized in mid amphibolite facies - 550-600ºC as calculated from mineral equilibria. No microstructural (e.g. ductile deformation of olivine or chromite or compositional (e.g. mantle spinel remnant of mantle history was identified. A metamorphic event M2 occurred in the low amphibolite facies along 100 m-wide shear zones, followed by intense serpentinization (M3 and narrow 1-3 m-wide shear zones (M4 containing asbestos.

  1. Selective extraction procedure and its importance in a natural analogue study. Case study at the Koongarra uranium deposit

    International Nuclear Information System (INIS)

    A sequential extraction procedure was used to study the distribution of uranium in mineral phases of rocks at the Koongarra uranium deposit as a natural analogue study. The mineral phases studied were adsorbed materials, amorphous iron minerals, crystalline iron minerals, chlorite, and remaining residual mineral phases. The majority of uranium in samples from the weathered zone coexist within crystalline iron minerals, and uranium in the primary ore body mainly occurred as uranium minerals. Downgradient in the unweathered zone, the concentration of uranium in rock was relatively low. From the 234U/238U activity ratios in extracted phases, 234U enrichment was observed in residual mineral phases coated in a microscale by iron minerals, possibly by alpha recoil effect. (author)

  2. Surface Microtextures of Slipping Zone Soil of Some Landslides in the Three Gorges Reservoir District and Their Significance

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The mineral assemblage and content and surface microtextures of slipping zone soil of several landslides in the Three Gorges Reservoir District have been analyzed using the scanning electron microscope (SEM) and X-ray diffractometer (XRD). All the mineral assemblages are similar in these landslides. The main minerals are montmorillonite, illite, kaolinite, chlorite, quartz and feldspar. There are two kinds of surface microtexture in the slipping zone soil, i.e., linear scratches and arcuate scratches. Based on analyses of the changes of the microtextures, one can obtain information about the number, directions and stages of landslide movements. The authors have also studied the mechanism of landslide formation, evaluated the stability of landslides and revival possibility of ancient landslides and forecasted the activity of similar landslides in different districts. The surface microtexture features of stable landslides and mobile landslides are summarized and it is concluded that the existence of filamentous bacteria may result in or increase movements of landslides.

  3. Identificación de metabasaltos alterados mediante datos ASTER Identification of altered metabasalts from ASTER data

    Directory of Open Access Journals (Sweden)

    Silvia Castro Godoy

    2010-06-01

    Full Text Available Los datos del sensor ASTER permitieron desarrollar una metodología sencilla, utilizando las bandas del infrarrojo de onda corta (subsistema SWIR, para prospectar cuerpos ígneos alterados que manifiestan diferencias espectrales con respecto a la roca de caja. A modo de ejemplo se detectó la alteración clorítica presente en metabasaltos intercalados en metasedimentitas de la Formación Puntilla de Uspallata en la Precordillera mendocina.ASTER data allowed developing a simple methodology, using the Short Wave Infrared spectral bands (SWIR, in order to detect alteration minerals that affect igneous bodies and have spectral differences with the country rock. As an example chloritic alteration was detected in metabasalts interbedded in metasediments of Puntilla de Uspallata Formation, Precordillera Mendocina.

  4. Palaeoproterozoic Volcanic Massive Sulphides (VMS) in the Lithuanian crystalline basement: evidences for a back-arc tectonic setting

    Science.gov (United States)

    Skridlaite, Grazina; Siliauskas, Laurynas

    2014-05-01

    In the southwestern part of the East European Craton (EEC), several events of Palaeoproterozoic volcanic arc magmatic activity were recognized in the concealed crystalline basement. In Lithuania, the TTG suites of 1.89 Ga and 1.86-1.84 Ga were later metamorphosed in amphibolite and granulite facies conditions. Remnants of a volcano-sedimentary sequence metamorphosed in green schist and amphibolite facies conditions were discovered in central and southern Lithuania. In southern Lithuania, the upper part of the Lazdijai 13 (Lz13) drilling (at c. 493 m depth) consists of exhalitic quartz chlorite cherts mixed with andesitic rocks. The rocks are impregnated with magnetite in some places replacing calcite. Most of the magnetite grains are overgrown by a dendritic kovelite, which may have formed while magnetite was still in aqueous surrounding. Other accessory minerals are xenotime, zircon, apatite, Sr-Ba sulphates etc. The cherts are underlain by a metaandesite which volcanic structures were obscured by hydrothermal alteration, i.e. the idiomorphic magnetite crystals and porphyritic plagioclase grains were replaced by clay minerals and quartz or muscovite in many places. Thin metamorphosed mudstone layers turned into garnet, biotite (+/-staurolite) and chlorite schists. The rocks were affected by silicification, chloritization, argilitization and carbonatization. Taking into account the rock composition, micro and macro scale alteration zones and absence of breccia, the whole package resembles an outer part of the VMS stockwork. The lower boundary at 526 m is sharp, marked by a quartz vein, below which lies quartz, biotite (+/- chlorite) bearing schist with minor tremolite (former sandstone). It was intensely affected by silicification, and was enriched in Na, K and Ca. Accessory minerals are monazite, xenotime, apatite and detrital zircon. The schist exhibits fine mineral foliation, and is fine-grained. A 4 m thick granitic vein cuts the rock at 654 m depth, below

  5. Studies of radionuclide sorption by clays in the Culebra dolomite at the WIPP site, southeastern New Mexico

    International Nuclear Information System (INIS)

    The ability of radionuclide-rock interactions to retard the migration of plutonium and uranium within clay-lined fractures in the Culebra Dolomite Member of the Rustler Formation is being estimated in support of the performance assessment of the Waste Isolation Pilot Plant. This paper describes progress in three coordinated studies: (1) characterization of the properties of the groundwater and minerals in the Culebra that will control radionuclide retardation; (2) development of a thermodynamic model for the adsorption of uranium onto corrensite, the mixed chlorite-smectite clay mineral found in Culebra fractures; and (3) development of a database of equilibrium constants and interaction parameters for calculations of the aqueous speciation of uranium and plutonium in Na-Cl-Ca-SO4-CO3 solutions which contain organic ligands such as EDTA and range in ionic strength from approximately 0.8 - 6.0 molal. 22 refs., 6 figs., 1 tab

  6. METARHYOLITES OF VRANICA MOUNTAIN IN PALEOZOIC OF CENTRAL BOSNIA

    Directory of Open Access Journals (Sweden)

    Vladimir Majer

    2001-12-01

    Full Text Available Metharyolites of Vranica mountain are roks of emphasized porphyritic texture containing phenocrysts of quartz, K.feldspar and very rarely albite. The groundmass is microcrystallinic, characterized by finegrained phengite, biotite and area consisting of granophyric intergrowths of quartz and feldspar. Accessory minerals are ilmenite, rutila, apatite, zircon and chlorite. Metarhyolites are peraulminous rocks (PI=1.-4.1 having dominantly potassium character (K2O/Na2O=1,3-13,8. Incompatible elements are enriched relative to the normalizing chondrite composition, pointing to the crustal origin of metarhyolite magma. Although phengites typically occur in high pressure rocks, it seems that phengites of metarhyolites of Vranica mountain belong to the seldom group of phengites occurring in the low to medium pressure rocks (the paper is published in Croatian.

  7. Soap-stone in architecture of North European cities. A nomination as a candidate for a Global Heritage Stones Resource

    Science.gov (United States)

    Bulakh, Andrey

    2016-04-01

    Soap stone represents soft Proterozoic rock type from the deposit Nunnalahti situated on the western shore of the big Lake Pielinen in Eastern Finland. It consists of talc (40 - 50 %), magnesite MgCO3 (40 - 50 %), chlorite (5 - 8 %), dolomite, calcite, etc. The colour of the stone is very spectacular and varies from yellow and brownish-yellow to grey, greenish grey. The soft stone is a highly workable material for a sculptor's chisel. It was one of the most popular ornamental rocks used architecture of the Modern style in St Petersburg, Helsinki, Turku, Tampere and other North European cities lately in the XIX-th centuries. Examples are given and discussed. References: Bulakh, A.G., Abakumova, N.B., and Romanovsky, J.V. St Petersburg: a History in Stone. 2010. Print House of St Petersburg State University. 173 p. (In English).

  8. Spinifex-textured komatiites in the south border of the Carajas ridge, Selva Greenstone belt, Carajás Province, Brazil

    Science.gov (United States)

    Siepierski, Lincoln; Ferreira Filho, Cesar Fonseca

    2016-03-01

    Spinifex-textured komatiites in the Selva greenstone belt are the first unequivocal examples of komatiites in the Transition Subdomain of the Carajás Mineral Province. Outcrops of spinifex-textured komatiites, located ∼1.5 km to the south of the Carajás ridge, were discovered during regional exploration for Ni-Cu-(PGE) sulfide deposits by VALE. They are associated with a 3.8 km long unit consisting of variable types of ultramafic rocks (talc schist, serpentinite and spinifex-textured komatiite). This ultramafic unit follows the steep dipping NW-SE trending Selva greenstone belt composed mainly by quartz-chlorite schists (interpreted as metasediments) and chlorite-actinolite schists (interpreted as metabasalts). Greenschist facies metamorphic parageneses characterize all rock types in the Selva greenstone belt. The komatiitic rocks in the Selva belt comprise a sequence of flows consisting of an upper spinifex-textured layer and a lower olivine cumulate layer. Although the spinifex and cumulus textures are well preserved in the field, the primary mineralogy of the komatiites has been completely replaced by greenschist facies metamorphic minerals. Platy olivine spinifex texture, consisting of an array of roughly parallel olivine plates, and random spinifex texture, consisting of randomly oriented olivine plates, are the most common primary volcanic textures in komatiites in the Selva greenstone belt. Platy and random spinifex texture is defined by former plates of olivine replaced by serpentine with minor actinolite, chlorite and magnetite, alternating with former matrix replaced by abundant actinolite and minor chlorite, talc, serpentine, and magnetite. The domains between olivine plates in both platy and random spinifex-textured rocks contain irregular arrays of fine-grained parallel crystals, representing primary fine-grained "quench" clinopyroxene crystals replaced by actinolite. Spinifex-textured komatiites have MgO contents bracket between 22.8 and 26.9 wt

  9. Uranium deposit research, 1983

    International Nuclear Information System (INIS)

    Research on uranium deposits in Canada, conducted as a prerequisite for assessment of the Estimated Additional Resources of uranium, revealed that (a) the uranium-gold association in rudites of the Huronian Supergroup preferably occurs in the carbon layers; (b) chloritized ore at the Panel mine, Elliot Lake, Ontario, occurs locally in tectonically disturbed areas in the vicinity of diabase dykes; (c) mineralization in the Black Sturgeon Lake area, Ontario, formed from solutions in structural and lithological traps; (d) the Cigar Lake deposit, Saskatchewan, has two phases of mineralization: monomineralic and polymetallic; (e) mineralization of the JEB (Canoxy Ltd.) deposit is similar to that at McClean Lake; (f) the uranium-carbon assemblage was identified in the Claude deposit, Carswell Structure; and (g) the Otish Mountains area, Quebec, should be considered as a significant uranium-polymetallic metallogenic province

  10. Features of Clay Minerals in the YSDP102 Core on the Continental Shelf of the Southeast Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    JIANG Xuejun; QU Gaosheng; LI Shaoquan

    2004-01-01

    Ninety-eight clay mineral samples from the YSDP102 core were analyzed by x-ray diffractometer to study the four clay minerals: illite, chlorite, kaolinite and smectite. Twenty-eight samples had been analyzed on the laser particle-size analyzer to reveal the particle features of the sediments. Distribution of the clay minerals and the particle characteristics in the YSDP102 core show that the core experienced three different depositional periods and formed three different sedimentary intervals due to different sediment sources and different depositional environments. Features of the clay minerals and the heavy minerals in the YSDP102 core indicate that coarse-grained sediments and fine-grained sediments result from different sources. The Yellow Sea Warm Current has greatly influenced the sedimentary framework of this region since the current's formation.

  11. Clay mineral distributions in the southern Yellow Sea and their significance

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    To better understand the characteristics of the clay minerals in the southern Yellow Sea, the X-ray quantitative determinations have been carried out for the surface samples obtained from the Yellow Sea. With newly compiled clay mineral synoptic maps, the depositional processes were described for four main clay minerals (illite, chlorite, kaolinite and smectite). The analysis shows that most clay minerals are of terrigenous source with the Huanghe River acting as the major sediment supplier. Besides, the source of muddy sediments in the Yellow Sea was also discussed. As for the central Yellow Sea mud (CYSM), the sediments in its northern part mainly come from the Huanghe River, and those in the rest are of multi-origin. Very similarly, a large amount of sediments in the northern part of the southeastern Yellow Sea Mud (SEYSM) derive from the Keum River and Yeongsan River, while those in the southern part are of multi-origin.

  12. Lability of soil organic carbon in tropical soils with different clay minerals

    DEFF Research Database (Denmark)

    Bruun, Thilde Bech; Elberling, Bo; Christensen, Bent Tolstrup

    2010-01-01

    Soil organic carbon (SOC) storage and turnover is influenced by interactions between organic matter and the mineral soil fraction. However, the influence of clay content and type on SOC turnover rates remains unclear, particularly in tropical soils under natural vegetation. We examined the lability....... Basal soil respiration rates were determined from bulk soils and soil fractions. Substrate induced respiration rates were determined from soil fractions. SOC lability was significantly influenced by clay mineralogy, but not by clay content when compared across contrasting clay minerals. The lability...... of SOC in tropical soils with contrasting clay mineralogy (kaolinite, smectite, allophane and Al-rich chlorite). Soil was sampled from A horizons at six sites in humid tropical areas of Ghana, Malaysian Borneo and the Solomon Islands and separated into fractions above and below 250 µm by wet sieving...

  13. Petrographic and EMP study of metamorphic rocks from the Variscan basement of Dinarides (Vranica Mountains, Bosnia and Herzegovina)

    International Nuclear Information System (INIS)

    The Vranica Mountains are located in the middle part of Bosnia and Herzegovina or in the southeastern part of the Mid - Bosnian schist Mountains (MBSM). The Mid - Bosnian schist Mountains represent one of the largest allochtonous Paleozoic terranes in the Dinarides. This region is characterized by a multistage geodynamic evolution. The presented results concern Variscan metamorphism of the Silur-Devonian protolith formations that occurred mainly during the Early Carboniferous in LT/MP greenschist facies. Petrographical description of metamorphic rocks is completed by EMPA of muscovite, chlorite and chloritoid. The Early Alpine metamorphic overprint is related to the closure of a Tethyan Basin and Early Cretaceous collision of the Adria microplate with the Tissia-Moesia continental Blocks. The Neo-Alpine metamorphic overprint occurred due to the collision of the African and Euroasian Plates. (authors)

  14. Mineralogy of a mudstone at Yellowknife Bay, Gale crater, Mars.

    Science.gov (United States)

    Vaniman, D T; Bish, D L; Ming, D W; Bristow, T F; Morris, R V; Blake, D F; Chipera, S J; Morrison, S M; Treiman, A H; Rampe, E B; Rice, M; Achilles, C N; Grotzinger, J P; McLennan, S M; Williams, J; Bell, J F; Newsom, H E; Downs, R T; Maurice, S; Sarrazin, P; Yen, A S; Morookian, J M; Farmer, J D; Stack, K; Milliken, R E; Ehlmann, B L; Sumner, D Y; Berger, G; Crisp, J A; Hurowitz, J A; Anderson, R; Des Marais, D J; Stolper, E M; Edgett, K S; Gupta, S; Spanovich, N

    2014-01-24

    Sedimentary rocks at Yellowknife Bay (Gale crater) on Mars include mudstone sampled by the Curiosity rover. The samples, John Klein and Cumberland, contain detrital basaltic minerals, calcium sulfates, iron oxide or hydroxides, iron sulfides, amorphous material, and trioctahedral smectites. The John Klein smectite has basal spacing of ~10 angstroms, indicating little interlayer hydration. The Cumberland smectite has basal spacing at both ~13.2 and ~10 angstroms. The larger spacing suggests a partially chloritized interlayer or interlayer magnesium or calcium facilitating H2O retention. Basaltic minerals in the mudstone are similar to those in nearby eolian deposits. However, the mudstone has far less Fe-forsterite, possibly lost with formation of smectite plus magnetite. Late Noachian/Early Hesperian or younger age indicates that clay mineral formation on Mars extended beyond Noachian time.

  15. Rayleigh-type parametric chemical oscillation.

    Science.gov (United States)

    Ghosh, Shyamolina; Ray, Deb Shankar

    2015-09-28

    We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained Rayleigh-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions. PMID:26429035

  16. Parametric spatiotemporal oscillation in reaction-diffusion systems.

    Science.gov (United States)

    Ghosh, Shyamolina; Ray, Deb Shankar

    2016-03-01

    We consider a reaction-diffusion system in a homogeneous stable steady state. On perturbation by a time-dependent sinusoidal forcing of a suitable scaling parameter the system exhibits parametric spatiotemporal instability beyond a critical threshold frequency. We have formulated a general scheme to calculate the threshold condition for oscillation and the range of unstable spatial modes lying within a V-shaped region reminiscent of Arnold's tongue. Full numerical simulations show that depending on the specificity of nonlinearity of the models, the instability may result in time-periodic stationary patterns in the form of standing clusters or spatially localized breathing patterns with characteristic wavelengths. Our theoretical analysis of the parametric oscillation in reaction-diffusion system is corroborated by full numerical simulation of two well-known chemical dynamical models: chlorite-iodine-malonic acid and Briggs-Rauscher reactions. PMID:27078346

  17. COMPOSITION OF MINERAL PHASES OF THE GHIDIRIM DIATOMITE

    Directory of Open Access Journals (Sweden)

    Vasile Rusu

    2007-06-01

    Full Text Available Studies of the mineralogical composition of diatomite from the Ghidirim location of RM, as well as of the extracted clay phase are presented. The mineral phase of the diatomite contains a number of clay minerals, like montmorillonite (in a mixture with insignificant quantities of slightly chloritized montmorillonite, illite and kaolinite. Diatomite contains also non-clay components as fine-dispersed quartz and amorphous material, the more probable sources of which are opal, amorphous alumosilicates, aluminum and iron hydroxides. The applied procedure for separation of clay fractions by sizing settling in liquid media proves to be very useful, enabling possibilities for more accurate identification of the clay constituents of diatomic material. Procedure allows to separate very clean clay fraction especially rich in montmorillonite, which can be utilized itself as mineral adsorbent for practical purposes.

  18. Catalysis of aluminosilicate clay minerals to the formation of the transitional zone gas

    Institute of Scientific and Technical Information of China (English)

    雷怀彦; 师育新; 关平; 房玄

    1997-01-01

    It has been shown that the major clay minerals of the biothermocatalytic transitional zone source rock are montmorillonite, illite/montmorillonite (I/M) interlayer mineral, illite, kaolinite and chlorite. Within the depth of the transitional zone, montmorillonite could convert to the I/M ordered interlayer mineral via the I/M disordered one, i.e. in the intercrystalline layer of montmorillonite, Al3+ replaces Si4+ abundantly, resulting in a surface charge imbalance and the occurrence of a surface acidity. By means of the pyridine analytic method, the surface acidity of these aluminosilicate clay minerals is measured. The catalysis of aluminosilicate clay minerals, such as montmorillonite, illite and kaolinite to the thermo-degraded gas formation of the transitional zone is simulated in the differential thermal analysis-gas chromatography system and the alcohol dehydration catalyzed by clay minerals is employed to discuss this catalytic mechanism. Experiments have shown that montmorillonite is the major

  19. 新型消毒剂-ClO2的制备方法及应用现状%PREPARATION OF NEW DISINFECTANT-ClO2 AND ITS APPLICATION

    Institute of Scientific and Technical Information of China (English)

    郑建华; 韩舞鹰

    2001-01-01

    The preparation method of ClO2, its some present products and application are introduced in this paper. Its preparation methods mainly include chemical and electrolysis methods, and their raw materials are mainly sodium chlorate, sodium chlorite and table salt. The present chloride dioxide products are mainly the stable ClO2 aqueous solution and solid chloride dioxide; the solid chloride dioxide has adsorbing type, gelatifying type and mono-packing type etc. due to different preparation technique. They are extensively applied to the aspects of disinfection, sterilization, algue removal, pulp-bleaching, air purification, food antisepsis and retaining freshness etc. of drinking water, industrial wastewater, hospital sewage, industrial cycle cooling water, fowl slaughter, indoor hygiene, beer production and aquiculture etc.%本文详细地介绍了二氧化氯的制备方法和现有的几种二氧化氯制品及其应用。

  20. MECHANISM OF CHLORATE FORMATION IN CHLORINE DIOIXDE DELIGNIFICATION

    Institute of Scientific and Technical Information of China (English)

    Byung-HoYoon; Li-JunWangI; Se-JongKim

    2004-01-01

    The effect of pH on chlorate formation duringchlorine dioxide delignification of oxygen delignifiedkraft pulp was studied. Chlorate formation was foundto increase slightly when pH was increased from 1.8to 2.5, further increase of pH decreased chlorateformation.The above phenomenon is explained by thecombination of two mechanisms, one by the reactionbetween hypochlorous acid and chlorite, another bythe effect of chlorine on the regeneration of chlorinedioxide. The first mechanism suggests that chlorateformation is highly dependent on HC10concentration which decreases with increasing pHand causes chlorate formation to behave in the sametrend. The second mechanism suggests that chlorinefavors the regeneration of chlorine dioxide whileHCIO favors chlorate formation, thus lowering thepH from about 4 to the acidic end should decreaseschlorate formation. Thethe maximum formation2.5.two opposite effects lead toof chlorate at around pH

  1. Reversed flow injection spectrophotometric determination of low residuals of chlorine dioxide in water using chlorophenol red

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel,simple,rapid,sensitive and highly selective flow injection procedure for the spectrophotometrie determination of chlorine dioxide in the presence of other chlorine species,viz,free chlorine,chlorite,chlorate and hypoehlorite,is developed.The method is based on the discoloration reaction between chlorine dioxide and chlorophenol red and can overcome the shortcomings existed in direct speetrophotometrie determination for chlorine dioxide owing to the serious interference of free and combined chlorine.The procedure gave a linear calibration graph over the range 0-0.71 mg/L of chlorine dioxide.With a detection limit of 0.024 mg/L and a sample throughput of 60 samples/h.

  2. An oxygen isotope and geochemical study of meteoric-hydrothermal systems at Pilot Mountain and selected other localities, Carolina slate belt

    Science.gov (United States)

    Klein, T.L.; Criss, R.E.

    1988-01-01

    Several epigenetic mineral deposits in the Carolina slate belt are intimately related to meteoric-hydrothermal systems of late Precambrian and early Paleozoic age. At Pilot Mountain, low 18O rocks correlate well with zones of strong silicic alteration and alkali leaching accompanied by high alumina minerals (sericite, pyrophyllite, andalusite ?? topaz) and anomalous concentrations of Cu, Mo, Sn, B, and Au. A magmatic source for much of the sulfur and metal is likely, and a subordinate magmatic water component in the fluid of the central zone is possible. This central zone is surrounded by a >30 km2 peripheral zone of low 18O sericite schists, chlorite-sericite schists, and andesitic volcanic rocks. Reconnaissance studies of other alteration zones in the Carolina slate belt have so far disclosed the involvement of meteoric-hydrothermal fluids at the Snow Camp pyrophyllite deposit, at the Hoover Hill and Sawyer Au mines, and probably at the Haile and Brewer Au mines. -from Authors

  3. A field trip guidebook to the type localities of Marland Billings' 1935 Paleozoic bedrock stratigraphy near Littleton, New Hampshire

    Science.gov (United States)

    Rankin, Douglas W.; Rankin, Mary B.

    2014-01-01

    Marland Billings' classic paper published in 1937 in the Geological Society of America Bulletin established a succession of six stratigraphic units in rocks of low metamorphic grade near Littleton, New Hampshire. The two youngest units are fossiliferous in the area, with ages established at the time as “middle” Silurian and Early Devonian. Billings and students mapped the same stratigraphic section in adjacent areas of progressively higher regional metamorphic grade. This work laid the foundation upon which a major part of subsequent work in New England has been directly or indirectly built. This guidebook was written for a field trip held in March 2013 to visit roadcuts that are as close as possible in March to the type localities or areas of Billings’ six-fold stratigraphic succession. Ten stops are in rocks of chlorite grade of Acadian(?) metamorphism; the final stop visits amphibolite of the Ammonoosuc Volcanics. Fieldwork by the authors over the past 20 years confirms Billings’ broad conclusions.

  4. Rayleigh-type parametric chemical oscillation.

    Science.gov (United States)

    Ghosh, Shyamolina; Ray, Deb Shankar

    2015-09-28

    We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained Rayleigh-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions.

  5. Parametric spatiotemporal oscillation in reaction-diffusion systems.

    Science.gov (United States)

    Ghosh, Shyamolina; Ray, Deb Shankar

    2016-03-01

    We consider a reaction-diffusion system in a homogeneous stable steady state. On perturbation by a time-dependent sinusoidal forcing of a suitable scaling parameter the system exhibits parametric spatiotemporal instability beyond a critical threshold frequency. We have formulated a general scheme to calculate the threshold condition for oscillation and the range of unstable spatial modes lying within a V-shaped region reminiscent of Arnold's tongue. Full numerical simulations show that depending on the specificity of nonlinearity of the models, the instability may result in time-periodic stationary patterns in the form of standing clusters or spatially localized breathing patterns with characteristic wavelengths. Our theoretical analysis of the parametric oscillation in reaction-diffusion system is corroborated by full numerical simulation of two well-known chemical dynamical models: chlorite-iodine-malonic acid and Briggs-Rauscher reactions.

  6. Petrography and geochemistry of basaltic rocks from the Conrad fracture zone on the America-Antarctica Ridge

    Science.gov (United States)

    le Roex, Anton P.; Dick, Henry J. B.

    1981-06-01

    Intrusive and extrusive basaltic rocks have been dredged from the Conrad fracture zone (transecting the slow-spreading America-Antarctica Ridge). The majority of rocks recovered are holocrystalline with the dominant mineral assemblage being plagioclase plus clinopyroxene with or without minor Fe-Ti oxides (olivine occurs in only three samples) and many of the samples show evidence of extensive alteration. Secondary minerals include chlorite, actinolite, K- and Na-feldspar, analcite and epidote. In terms of bulk chemistry the rocks are characterized by their generally evolved and highly variable compositions (e.g. Mg *=0.65-0.35;TiO 2=0.7-3.6%;Zr=31-374ppm;Nb=differentiation observed in the Conrad fracture zone basalts implies some additional constraint other than spreading rate on the formation of ferrobasalt and reaffirms the importance of extensive crustal differentiation during the production of this basalt type.

  7. Petrology, composition, and age of intrusive rocks associated with the Quartz Hill molybdenite deposit, southeastern Alaska.

    Science.gov (United States)

    Hudson, T.; Smith, James G.; Elliott, R.L.

    1979-01-01

    A large porphyry molybdenum deposit (Quartz Hill deposit) was recently discovered in the heart of the Coast Range batholithic complex about 70 km E of Ketchikan, SE Alaska. Intrusive rocks associated with the mineral deposit form two composite epizonal to hypabyssal stocks and many dikes in country rocks. All observed metallization and alteration is within the Quartz Hill stock. Molybdenite forms fracture coatings and occurs in veins with quartz. Alteration is widespread and includes development of secondary quartz, pyrite, K-feldspar, biotite, white mica, chlorite, and zeolite. Field relations indicate that the stocks were emplaced after regional uplift and erosion of the Coast Range batholithic complex, and K-Ar data show that intrusion and alteration took place in late Oligocene time, about 27 to 30 Ma ago. Data from the Ketchikan quadrangle indicate that porphyry molybdenum metallization in the Coast Range batholithic complex is associated with regionally extensive but spotty, middle Tertiary or younger, felsic magmatism. -from Authors

  8. Evidence of heterogeneous crustal origin for the Pan-African Mbengwi granitoids and the associated mafic intrusions (northwestern Cameroon, central Africa)

    Science.gov (United States)

    Mbassa, Benoît Joseph; Kamgang, Pierre; Grégoire, Michel; Njonfang, Emmanuel; Benoit, Mathieu; Itiga, Zénon; Duchene, Stéphanie; Bessong, Moïse; Nguet, Pauline Wonkwenmendam; Nfomou, Ntepe

    2016-02-01

    The Mbengwi plutonics consist of intermediate to felsic granitoids forming a continuous magmatic series from monzonite to granite and mafic intrusions. Their mineralogical composition consists of quartz, plagioclases, K-feldspars, biotite, muscovite, and amphibole. The accessory phase includes opaque minerals + titanite ± apatite ± zircon, while secondary minerals are pyrite, phengite, chlorite, epidote, and rarely calcite. These plutonics are assigned high-K calc-alkaline to shoshonitic series, metaluminous to weakly peraluminous and mostly belong to an I-type suite (A/CNK = 0.63-1.2). They are typically post-collisional, with a subduction signature probably being inherited from their protoliths emplaced during the subduction phase. The Sr and Nd isotopic data evidence that these plutonics result from melting of the lower continental crust with variable contribution of the oceanic crust. Their geochemical features are similar to those of western Cameroon granitoids related to the Pan-African D1 event in Cameroon.

  9. Persistent blooms of surf diatoms along the pacific coast U. S. A. I. physical characteristics of the coastal region in relation to the distribution and abundance of the species

    Energy Technology Data Exchange (ETDEWEB)

    Garver, J.L.; Lewin, J.

    1981-01-01

    The surf diatom populations at thirteen beaches along the Oregon and Washington coast were studied from June 1977 through August 1978. Chaetoceros armatum T. West and Asterionella socialis Lewin and Norris, the two species responsible for the blooms, were present in the surf along beaches between Point Grenville, Washington, and Cape Blanco, Oregon. On the basis of the cell densities of these two species, the beaches were arranged into four distinct groups. Discriminant analysis showed that the four groups could also be completely separated by three discriminant functions composed of four physical variables: offshore bottomslope, per cent chlorite, per cent montmorillonite and beach length. The absence of surf diatoms at two beaches south of Cape Blanco can probably be explained by the unsuitable physical conditions along the coast south of the Cape.

  10. Ion chromatography in the manufacture of multilayer circuit boards

    Science.gov (United States)

    Smith, Robert E.

    1990-09-01

    Ion chromatography (IC) has proven useful in analyzing chemical solutions used in the manufacture of multilayer circuit boards. The manufacturing process is described briefly and previously published IC methods are reviewed. Then, methods are described for determining chlorate and chlorite in a brown oxide solution; salicylic acid in an epoxy cure agent; formate, sulfate, and tartrate in an electroless copper bath; anionic detergents in a tin-lead brightener and in a cleaning solution; and aqueous photoresist and nonionic brightener in a tin-lead bath. Anion exchange, reverse phase HPLC on a poly(styrene/divinylbenzene), PS/DVB, column and 2-D liquid chromatography also are described. Chemically suppressed conductivity and photometric detection are used.

  11. Late-Neoproterozoic hydrothermal fluid activity in the Tandilia belt, Argentina

    Directory of Open Access Journals (Sweden)

    Juan C Martínez

    2013-09-01

    Full Text Available In the Barker - Villa Cacique area, Tandilia belt, alteration mineral assemblages were studied by petrography, XRD and EMPA at three different stratigraphic levels: (1 a phyllic alteration at the unconformity palaeoproterozoic basement-neoproterozoic sedimentary succession (TLPU; (2 an advanced argillic alteration in the Las Águilas Formation (middle level; and (3 a phyllic alteration on pyroclastic rocks of the Olavarría Formation (upper level. Special emphasize was placed on the chemical characterization of K-white micas and chlorites. Secondary K-white micas of altered migmatites, from the Las Aguilas and Olavarría Formations have a low paragonite content (Na* 9.5 km for the entire sedimentary pile. Hot fluids would rise from deep-seated realms, metamorphic and/or hidden igneous sources. A correlation with a Brasiliano thermo-tectonic event is hypothesized.

  12. Bench and Full Scale Study of Removal Effect and Mutagenicity on Mesocyclops Leukarti with Chlorine Dioxide

    Institute of Scientific and Technical Information of China (English)

    ZUO Jin-long; YANG Wei; LIU Yan-an; LIN Tao

    2006-01-01

    Mesocyclops Leukarti of zooplankton propagates excessively in eutrophic water body and it can not be effectively inactivated by the conventional process in drinking waterworks for its special surface structure. In this paper, a study of removal efficiency on Mesocyclops Leukarti with chlorine dioxide in a drinking waterworks was performed.Bench scale results showed that chlorine dioxide is more effective against Mesocyclops Leukarti. And Mesocyclops Leukarti could be effectively removed from water by 1.0 mg/L chlorine dioxide preoxidation cooperated with the conventional process during the full scale study. The chlorite, by-preduct of prechlorine dioxide, was constant at 0.45 mg/L after filtration, which was lower than the critical value of the USEPA. GC-MS examination and Ames test showed that the quantity of organics and the mutagenicity in the water treated by chlorine dioxide is obviously less than that of prechlorination.

  13. STABLE CARBON ISOTOPE ANALYSIS OF SUBFOSSIL WOOD FROM AUSTRIAN ALPS

    Science.gov (United States)

    KŁUSEK, MARZENA; PAWEŁCZYK, SŁAWOMIRA

    2015-01-01

    The presented studies were carried out in order to check the usefulness of subfossil wood for stable isotope analysis. The aim of research was also to define the optimal method of subfossil samples preparation. Subfossil samples used during the presented studies are a part of the multi-century dendrochronological scale. This chronology originates in an area situated around a small mountain lake — Schwarzersee, in Austria. The obtained results of stable carbon isotope measurements confirmed that the method of α-cellulose extraction by the application of acidic sodium chlorite and sodium hydroxide solutions removes resins and other mobile compounds from wood. Therefore, in the case of the analysed samples, the additional chemical process of extractives removing was found to be unnecessary. Studied wood samples contained an adequate proportion of α-cellulose similar to the values characteristic for the contemporary trees. This proved an adequate wood preservation which is essential for the conduction of isotopic research. PMID:26346297

  14. Ultramafic rocks in the Namurian C series in the Zebrzydowice area (Rybnik coal region)

    Energy Technology Data Exchange (ETDEWEB)

    Jochemczyk, L.

    1984-08-01

    The chemical and physical properties as well as origin of ultramafic rock samples from the Zebrzydowice area in the Rybnik coal region are evaluated. The ultramafic rocks detected by drilling were situated at depths of 1035 m in the top of dacite-andesite system and thermally alterated claystones. Chemical analyses and X-ray examination show that the ultramafic rock consists of secondarily alterated peridotite. The peridotite consists of chlorite-serpentite, phlogopite, bastite, nepheline and opaque minerals. Its chemical composition is characterized by reduced content of silica and a high content of ferric oxide. The ultramafic rock in the Zebrzydowice area differs from mineral and chemical composition of igneous rocks which occur in Carboniferous strata in the west and the southwest of the Upper Silesia basin. Rock of this type has been recorded in the Upper Silesia basin for the first time. 12 references.

  15. Development of the Extra-low Permeability Oilfield of Ansai

    Institute of Scientific and Technical Information of China (English)

    Hu Wenrui

    1995-01-01

    @@ Reservoir Characteristics Ansai Oilfield is located in Ordos Basin. Its regional structure is a large westward-dipping monocline with dip angle less than 1°. The main producing interval is in Yanchang formation,Triassic, and the depositional environment is a delta deposit of inland fresh water lake. This oilfield is distributed in distributary channel sandstone of delta plain,front underwater distributary channel sandstone and front river mouth bar sandstone of flowershape. Lithologic trap is the primary trap type and shows complex rhythm with average reservoir thickness of 11 to 15 m and Average porosity of 11% to14%. It is fine grained and well sorted sandy arkose. The cementing material is predominantly secondary chlorite, secondary laumontite and calcite with content of 11% to 14%.

  16. Mapping Hydrothermal Alterations in the Muteh Gold Mining Area in Iran by using ASTER satellite Imagery data

    Science.gov (United States)

    Asadi Haroni, Hooshang; Hassan Tabatabaei, Seyed

    2016-04-01

    Muteh gold mining area is located in 160 km NW of Isfahan town. Gold mineralization is meso-thermal type and associated with silisic, seresitic and carbonate alterations as well as with hematite and goethite. Image processing and interpretation were applied on the ASTER satellite imagery data of about 400 km2 at the Muteh gold mining area to identify hydrothermal alterations and iron oxides associated with gold mineralization. After applying preprocessing methods such as radiometric and geometric corrections, image processing methods of Principal Components Analysis (PCA), Least Square Fit (Ls-Fit) and Spectral Angle Mapper (SAM) were applied on the ASTER data to identify hydrothermal alterations and iron oxides. In this research reference spectra of minerals such as chlorite, hematite, clay minerals and phengite identified from laboratory spectral analysis of collected samples were used to map the hydrothermal alterations. Finally, identified hydrothermal alteration and iron oxides were validated by visiting and sampling some of the mapped hydrothermal alterations.

  17. Hydrochemical measures and salinity studies in Inhanhuns` waters, Ceara State, Brazil; Medidas hidroquimicas e estudo da salinizacao das aguas nos Inhamuns

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Carlos Henrique; Santiago, Marlucia Freitas; Mendes Filho, Josue; Frischkorn, Horst [Ceara Univ., Fortaleza, CE (Brazil)

    1996-08-01

    The Inhamuns region is one of the most arid in Ceara Waters exhibit very high salinity. Here we evaluate measurements of chemical parameters (electrical conductivity, EC, and major ions) and {delta}{sup 18} O for waters from wells, springs and surface reservoirs. Results show that springs, with EC of up to nearly 5000 {mu}S/cm, are fed by pluvial water, exchange through dams can be excluded. Electrical conductivity is well correlated with Na{sup +} Mg{sup ++} and Cl{sup -} for waters of various origins, whereas Ca{sup ++} correlates reasonably only for wells. We conclude that aerosol deposition is a major source of salt, Enrichment through evaporation constitutes the most important process for surface water salination. Dissolution of chlorite-silicates is the cause for the magnesian character of underground water. (author) 1 ref., 1 tab.

  18. Study of removal effect on Mesocyclops leukarti with oxidants

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Cyclops of zooplankton propagates prolifically in eutrophic waterbody and it cannot be exterminated by conventional disinfection process. The mutagenicity of Mesocyclops leukarti and its extermination with oxidants in a drinking waterworks in China were studied. Among five oxidants for use in bench-scale, chlorine dioxide is the most effective and the potassium permanganate is the weakest against Mesocyclops leukarti under the same conditions. Full-scale results showed that Mesocyclops leukarti could be effectively removed from water by 1.0 mg/L chlorine dioxide preoxidation combined with conventional removal physical process. After filtration, chlorite, a by-product of prechlorine dioxide, is stable at 0.45 mg/L, which is lower than the critical value of the USEPA. GC-MS examination and Ames test further showed that the quantity of organic substance and the mutagenicity in water treated by chlorine dioxide preoxidation are obviously less than those of prechlorination.

  19. ON THE BLACK LIQUOR AND RECYCLE COOKING OF AS-AQ STRAW PULP

    Institute of Scientific and Technical Information of China (English)

    Haiqiang Shi; Beihai He; Bingyue Liu

    2004-01-01

    Thick black liquor, thin black liquor and solid state sodium hydroxide are added to the liquor treated by sulfur dioxide, then the blended liquor is used to recycle cooking of straw pulp. The black liquor,separated liquor and pulp of every cycles are analyzed respectively. Result shows that the content of lignin and organism in recycle black liquor and separated liquor increases faster in the first three cycles and then continues to increase slowly till four or five times, after that it trends to a stable state. The main organism separated from waste liquor of AS-AQ treated by sulfur dioxide is alkali-lignin,above 50% of total lignin in black liquor. The yield of pulp made from recycle cooking is steady, the hardness of pulp has a great improvement with recycle cooking. The brightness of pulp reduces correspondingly before bleaching, and after bleaching the brightness of pulp is relatively high and steady at the same sodium hypo chlorite dosage.

  20. A Lattice Boltzmann Model for Oscillating Reaction-Diffusion

    Science.gov (United States)

    Rodríguez-Romo, Suemi; Ibañez-Orozco, Oscar; Sosa-Herrera, Antonio

    2016-07-01

    A computational algorithm based on the lattice Boltzmann method (LBM) is proposed to model reaction-diffusion systems. In this paper, we focus on how nonlinear chemical oscillators like Belousov-Zhabotinsky (BZ) and the chlorite-iodide-malonic acid (CIMA) reactions can be modeled by LBM and provide with new insight into the nature and applications of oscillating reactions. We use Gaussian pulse initial concentrations of sulfuric acid in different places of a bidimensional reactor and nondiffusive boundary walls. We clearly show how these systems evolve to a chaotic attractor and produce specific pattern images that are portrayed in the reactions trajectory to the corresponding chaotic attractor and can be used in robotic control.

  1. Hydrated silicate minerals on Mars observed by the Mars Reconnaissance Orbiter CRISM instrument.

    Science.gov (United States)

    Mustard, John F; Murchie, S L; Pelkey, S M; Ehlmann, B L; Milliken, R E; Grant, J A; Bibring, J-P; Poulet, F; Bishop, J; Dobrea, E Noe; Roach, L; Seelos, F; Arvidson, R E; Wiseman, S; Green, R; Hash, C; Humm, D; Malaret, E; McGovern, J A; Seelos, K; Clancy, T; Clark, R; Marais, D D; Izenberg, N; Knudson, A; Langevin, Y; Martin, T; McGuire, P; Morris, R; Robinson, M; Roush, T; Smith, M; Swayze, G; Taylor, H; Titus, T; Wolff, M

    2008-07-17

    Phyllosilicates, a class of hydrous mineral first definitively identified on Mars by the OMEGA (Observatoire pour la Mineralogie, L'Eau, les Glaces et l'Activitié) instrument, preserve a record of the interaction of water with rocks on Mars. Global mapping showed that phyllosilicates are widespread but are apparently restricted to ancient terrains and a relatively narrow range of mineralogy (Fe/Mg and Al smectite clays). This was interpreted to indicate that phyllosilicate formation occurred during the Noachian (the earliest geological era of Mars), and that the conditions necessary for phyllosilicate formation (moderate to high pH and high water activity) were specific to surface environments during the earliest era of Mars's history. Here we report results from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) of phyllosilicate-rich regions. We expand the diversity of phyllosilicate mineralogy with the identification of kaolinite, chlorite and illite or muscovite, and a new class of hydrated silicate (hydrated silica). We observe diverse Fe/Mg-OH phyllosilicates and find that smectites such as nontronite and saponite are the most common, but chlorites are also present in some locations. Stratigraphic relationships in the Nili Fossae region show olivine-rich materials overlying phyllosilicate-bearing units, indicating the cessation of aqueous alteration before emplacement of the olivine-bearing unit. Hundreds of detections of Fe/Mg phyllosilicate in rims, ejecta and central peaks of craters in the southern highland Noachian cratered terrain indicate excavation of altered crust from depth. We also find phyllosilicate in sedimentary deposits clearly laid by water. These results point to a rich diversity of Noachian environments conducive to habitability. PMID:18633411

  2. Mass change calculations of hydrothermal alterations within the volcanogenic metasediments hosted Cu-Pb (-Zn) mineralization at Halilar area, NW Turkey

    Science.gov (United States)

    Kiran Yildirim, Demet; Abdelnasser, Amr; Doner, Zeynep; Kumral, Mustafa

    2016-04-01

    The Halilar Cu-Pb (-Zn) mineralization that is formed in the volcanogenic metasediments of Bagcagiz Formation at Balikesir province, NW Turkey, represents locally vein-type deposit as well as restricted to fault gouge zone directed NE-SW along with the lower boundary of Bagcagiz Formation and Duztarla granitic intrusion in the study area. Furthermore, This granite is traversed by numerous mineralized sheeted vein systems, which locally transgress into the surrounding metasediments. Therefore, this mineralization closely associated with intense hydrothermal alteration within brecciation, and quartz stockwork veining. The ore mineral assemblage includes chalcopyrite, galena, and some sphalerite with covellite and goethite formed during three phases of mineralization (pre-ore, main ore, and supergene) within an abundant gangue of quartz and calcite. The geologic and field relationships, petrographic and mineralogical studies reveal two alteration zones occurred with the Cu-Pb (-Zn) mineralization along the contact between the Bagcagiz Formation and Duztarla granite; pervasive phyllic alteration (quartz, sericite, and pyrite), and selective propylitic alteration (albite, calcite, epidote, sericite and/or chlorite). This work, by using the mass balance calculations, reports the mass/volume changes (gain and loss) of the chemical components of the hydrothermal alteration zones associated with Halilar Cu-Pb (-Zn) mineralization at Balikesir area (Turkey). It revealed that the phyllic alteration has enrichments of Si, Fe, K, Ba, and LOI with depletion of Mg, Ca, and Na reflect sericitization of alkali feldspar and destruction of ferromagnesian minerals. This zone has high Cu and Pb with Zn contents represents the main mineralized zone. On the other hand, the propylitic zone is characterized by addition of Ca, Na, K, Ti, P, and Ba with LOI and Cu (lower content) referring to the replacement of plagioclase and ferromagnesian minerals by albite, calcite, epidote, and sericite

  3. Chemical and mineralogical analysis of devonian black-shale samples from Martin County, Kentucky; Carroll and Washington counties, Ohio; Wise County, Virginia; and Overton County, Tennessee, U.S.A.

    Science.gov (United States)

    Leventhal, J.S.; Hosterman, J.W.

    1982-01-01

    Core samples of Devonian shales from five localities in the Appalachian basin have been analyzed chemically and mineralogically. The amounts of major elements are similar; however, the minor constituents, organic C, S, phosphate and carbonate show ten-fold variations in amounts. Trace elements Mo, Ni, Cu, V, Co, U, Zn, Hg, As and Mn show variations in amounts that can be related to the minor constituents. All samples contain major amounts of quartz, illite, two types of mixed-layer clays, and chlorite in differing quantities. Pyrite, calcite, feldspar and kaolinite are also present in many samples in minor amounts. Dolomite, apatite, gypsum, barite, biotite and marcasite are present in a few samples in trace amounts. Trace elements listed above are strongly controlled by organic C with the exception of Mn which is associated with carbonate minerals. Amounts of organic C generally range from 3 to 6%, and S is in the range of 2-5%. Amounts of trace elements show the following general ranges in ppm (parts per million): Co, 20-40; Cu, 40-70; U, 10-40; As, 20-40; V, 150-300; Ni, 80-150; high values are as much as twice these values. The organic C was probably the concentrating agent, and the organic C and sulfide S together created an environment that immobilized and preserved these trace elements. Closely spaced samples showing an abrupt transition in color also show changes in organic C, S and trace-element contents. Several associations exist between mineral and chemical content. Pyrite and marcasite are the only minerals found to contain sulfide-S. In general, the illite-chlorite mixed-layer clay mineral shows covariation with organic C if calcite is not present. The enriched trace elements are not related to the clay types, although the clay and organic matter are intimately associated as the bulk fabric of the rock. ?? 1982.

  4. Studies on the preparation of value-added products for limestone

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Young Bae; Jeong, Soo Bok; Ko, Won Sik; Park, Je Shin; Oh, Jung Whan [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1997-12-01

    Most of limestone in our country was consumed by the cement and iron/steel making industries and the amount of that was up to 72 million ton in 1996. Recently, importation of high grade limestone that have properties of high whiteness and grade are increased with diversification of chemical products and powder as various qualified filler, because high grade limestone are limited and of few deposit in our country. Therefore, the purpose of this study has investigated to raise to high grade by economical processes with low grade of domestic limestone. In this year, first of all, we investigated the status of application utilize and related industries with the domestic limestone, and then being consideration with condition selected the adequate sample from Andong, Jungsun and Kumsan area. Magnetic materials were involved in impurities of sample, so magnetic separation method was applied in elimination of the ferro-magnetic materials and para-magnetic materials, such as chlorite, muscovite, quartz, dolomite, magnetite, feldspar and so on. The limestone sample has many kinds of impurity. Investigation of flotation was undertaken to eliminate impurities from limestone crude ore and the tests were performed to get a optimum condition adding oleic acid as a promoter, sodium silicate and sodium carbonate as a conditioning agents and MIBC as a frother, while to float the sulfide minerals added amyl xanthate as a promoter, and sulfuric acid as a pH regulator. And most of the impurities involving in flotation sink contained such as quartz, chlorite, muscovite, feldspar, dolomite and so on. Selective crushing and classification methods were performed to eliminate impurities depends on the mineral properties and should be the selective crushing methods are very useful at the manufacturing factory of heavy calcium carbonate with the dry milling system. (author). 36 refs., 46 tabs., 33 figs.

  5. Petrology and radiogeology of the Stripa pluton

    Energy Technology Data Exchange (ETDEWEB)

    Wollenberg, H.; Flexser, S.; Andersson, L.

    1980-12-01

    Both the quartz monzonite and the metavolcanic leptite which it intruded are strongly fractured. Two stages of fracture filling are evident; an earlier stage encompassing quartz, sericite, feldspar, epidote, and chlorite, and a later stage dominated by carbonate minerals. The Stripa quartz monozite is chemically and mineralogically distinct from other plutons in the region. Muscovite is the predominant mica in the quartz monzonite; biotite has been altered to chlorite, hornblende is absent, and accessory minerals are scarce. In contrast, in other plutons in the Stripa region, biotite and hornblende are prominent mafic minerals and accessory minerals are abundant. The Stripa quartz monzonite is also considerably more radioactive than the the leptite and other plutons in the region. Uranium and thorium abundances are both approx. 30 ppM, considerably higher than in normal granitic rocks where the thorium-to-uranium ratio generally exceeds 2. Potassium-argon dating of muscovite from the Stripa quartz monzonite indicates that this rock may be older, at 1691 million years than granitic rock of the neighboring Gusselby and Kloten massifs, whose ages, based on K-Ar dating of biotite, are respectively 1604 and 1640 m.y. Heat flow and heat productivity considerations show that although Stripa quartz monzonite contains high abundances of radioelements, the pluton has little efect on the regional heat flow. If it occurs in a layered plutonic setting, it is not more than 1.5 km thick; otherwise it may comprise a stock, dike, or border phase that is relatively small compared with the large granitic plutons exposed in the region.

  6. Mineralogical variations across Mariano Lake roll-type uranium deposits, McKinley County

    International Nuclear Information System (INIS)

    Mineralogy of core samples from the Mariano orebody was determined. The data obtained were used to develop exploration tools for roll-type uranium deposits. Preliminary interpretations of the physical and chemical conditions of ore deposition were made on the basis of paragenetic relationships. The host sandstones occur between the bentonitic rock units and contain scattered intercalations of detrital montmorillonitic material in the form of clay galls, stringers, and lenses derived from these bentonites. Authigenic clay minerals identified in the host rocks include cellular montmorillonite, platy chlorite, and pseudohexagonal books of kaolinite. The cellular montmorillonite is concentrated in the oxidized zone and appears to have formed prior to ore deposition. Authigenic chlorite is most abundant in the ore zone and has formed at the expense of cellular montmorillonite; its formation is interpreted as being related to the ore-forming processes. Kaolinite in sandstones is the last clay mineral to form and is enriched in the reduced zone. Calcite, considered typical of such deposits, is not found in this orebody. Iron-titanium oxides and their alteration products are the most abundant heavy-mineral species in the host rocks. In addition to anatase and rutile, the alteration products include hematite in the oxidized zone and pyrite in the ore and reduced zones. Carbonaceous material introudced later into the potential ore zone appears to have been responsible for the decomposition of Fe-Ti oxides and the formation of pyrite. The paragenetic relationship indicates oxidation of pyrite by mineralizing solutions, resulting in reduction and subsequent deposition of uranium. The positive correlation between organic carbon and uranium suggests that carbonaceous material also acted as a reductant for uranium

  7. Uranium deposits of Turamdih- Nandup area, Singhbhum district, Bihar and their spatial relationship

    International Nuclear Information System (INIS)

    The Turamdih-Nandup cluster of uranium deposits covering an area of 3.5 km2 in the western part of the Singhbhum shear zone includes low grade deposits of Turamdih (east, south, and west), Keruadungri west, central Keruadungri, and Nandup, holding a substantial part of the estimated uranium reserves of India. Chlorite-quartz schist with magnetite and apatite is the most common host for mineralization, besides chlorite-sericite-quartz schist and to a lesser extent feldspathic schist, all belonging to the Dhalbhum formation of lower proterozoic - late Archaean age. Surface structures indicate that the superimposition of at least three deformational episodes have resulted in transposing the ore body at different levels and shapes in the different sectors of the deposits. The overall structure deciphered in the area is a major asymmetrical synform, trending NW-SE. The uranium lodes are essentially parallel or subparallel to the schistosity. Sericite schists mark the lower part of the mineralized horizon in the subsurface. Evaluation and synthesis of surface and sub-surface data on lithological controls, geometry of the ore horizons, and nature of mineralisation from over 500 boreholes have revealed that the mineralisation in different blocks is in fact the manifestation of single ore body. Uranium mineralisation is of low grade (0.03-0.04 % U3O8), but is compensated by large thickness of ore horizons, some measuring up to 120 m. Further, ore horizons at places, occur very near to the surface making them easily amenable for open cast mining. (author). 18 refs., 7 figs., 2 tabs

  8. Geology of Wadi Wassif Area, Central Eastern Desert, Egypt, With Emphasis on Mineralogy of Stream Sediments

    International Nuclear Information System (INIS)

    This study deals with the geology and mineralogy of stream sediments at Wadi Wassif, C.E.D., Egypt. The area is built up of igneous and metamorphic rocks of Late Precambrian age in addition to Quaternary alluviam deposits. Geologically, the area consists of metavolcanics, older granitoids, Hammamat sediments, younger granites, and Quaternary sediments filling the streams of the studied area. Microscopically, metavolcanics comprise meta andesite, metadacite and crystal tuffs. They are weakly metamorphosed to the green schist facies (chlorite zone). Hammamat sediments comprise conglomerate, sandstone, siltstone and mud stone. They are weakly metamorphosed to the chlorite zone of the green schist facies. Gravity and magnetic separation techniques in addition to microscopic examination for the studied stream sediment samples were applied to evaluate the heavy minerals concentration of these sediments. The average heavy mineral concentration of the stream sediments of Wadi Wassif is 5.56%, ranging from 1.58% and 10.91%. These heavy minerals increase from upstream to downstream of Wadi Wassif. The average contents of the concerned heavy minerals in Wadi Wassif are 0.347% for zircon, 0.058% for thorite, 0.074% for monazite, 0.097 for titanite, 0.038% for rutile. The other heavy minerals include epidot, garnet in addition to opaque minerals; magnetite, ilmenite and hematite. The radiometric study of the stream sediments of Wadi Wassif indicates that the average concentrations of U and Th are 2.9ppm and 17ppm respectively, ranging from 1 to 4ppm for U and 8 to 28ppm for Th, which reveals a significant fractionation during weathering of these sediments.

  9. Mineralogical, geochemical and radiological characterisation of Selmo Formation in Batman area, Turkey.

    Science.gov (United States)

    Isik, Umit; Damla, Nevzat; Akkoca, Dicle Bal; Cevik, Uğur

    2012-06-01

    This work deals with the mineralogical, geochemical and radiological characterisations of Selmo Formation in Batman neighbourhood. The upper Miocene-Pliocene Selmo Formation is common in the centre of Batman and composed of carbonated sandy claystones and silty-sandy stone lenses. The common whole minerals of the samples are quartz, feldspars, calcite and dolomite. The clay minerals are smectite, illite, chlorite and mixed-layer clay (chlorite-smectite). The geochemical mean values of the samples are 51.7% SiO(2); 12.6% Al(2)O(3); 6.2% Fe(2)O(3); 3.6% MgO; 6.3% CaO; 1.1% Na(2)O; 1.7% K(2)O; 0.8% TiO(2); 0.2% P(2)O(5); 0.1% MnO; and 0.03% Cr(2)O(3). In addition, baseline maps for the concentrations of each radionuclide, the radium equivalent activity and the outdoor gamma dose rate distributions have been plotted for the study area. The mean activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs were determined to be 32, 24, 210 and 9 Bq kg(-1), respectively. The assessments of the radiological hazard indices, such as radium equivalent activity, absorbed dose rate in air, annual effective dose equivalent, excess lifetime cancer risk, external hazard index and internal hazard index, were calculated and compared with the internationally accepted reference values. This study shows that the concentrations of radioactivities in the measured samples were within the recommended safety limits and did not pose to be any significant source of radiation hazard.

  10. Mineral Sequestration of Carbon Dixoide in a Sandstone-Shale System

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tianfu; Apps, John A.; Pruess, Karsten

    2004-07-09

    A conceptual model of CO2 injection in bedded sandstone-shale sequences has been developed using hydrogeologic properties and mineral compositions commonly encountered in Gulf Coast sediments. Numerical simulations were performed with the reactive fluid flow and geochemical transport code TOUGHREACT to analyze mass transfer between sandstone and shale layers and CO2 immobilization through carbonate precipitation. Results indicate that most CO2 sequestration occurs in the sandstone. The major CO2 trapping minerals are dawsonite and ankerite. The CO2 mineral-trapping capacity after 100,000 years reaches about 90 kg per cubic meter of the medium. The CO2 trapping capacity depends on primary mineral composition. Precipitation of siderite and ankerite requires Fe+2 supplied mainly by chlorite and some by hematite dissolution and reduction. Precipitation of dawsonite requires Na+ provided by oligoclase dissolution. The initial abundance of chlorite and oligoclase therefore affects the CO2 mineral trapping capacity. The sequestration time required depends on the kinetic rate of mineral dissolution and precipitation. Dawsonite reaction kinetics is not well understood, and sensitivity regarding the precipitation rate was examined. The addition of CO2 as secondary carbonates results in decreased porosity. The leaching of chemical constituents from the interior of the shale causes slightly increased porosity. The limited information currently available for the mineralogy of natural high-pressure CO2 gas reservoirs is also generally consistent with our simulation. The ''numerical experiments'' give a detailed understanding of the dynamic evolution of a sandstone-shale geochemical system.

  11. Hydrothermal alteration in an exhumed crustal fault zone: geochemical mobility in the Caleta Coloso Fault, Atacama Fault System, Northern Chile

    Science.gov (United States)

    Arancibia, G.; Fujita, K.; Hoshino, K.; Mitchell, T. M.; Cembrano, J. M.; Gomila, R.; Morata, D.; Faulkner, D. R.; Rempe, M.

    2013-12-01

    Fault zones must be considered as complex and heterogeneous systems, with areas of high permeability that alternate with very low permeability bands. Strike-slip fault zones play an important role in fluid migration in the crust, and exhumed faults can provide insights into the interrelationships of deformation mechanisms, fluid-rock interactions and bulk chemical redistributions. We determined the mineral chemistry and whole-rock geochemistry of the damage zone and fault core of the Caleta Coloso Fault, a complex major crustal scale strike-slip fault in Northern Chile, in order to constrain the physical and chemical conditions of fluids that lead to strong hydrothermal alteration. Caleta Coloso Fault consists of variably altered protocataclasites, cataclasites and discrete bands of ultracataclasite derived from a protolith of Jurassic tonalite. Hydrothermal alteration associated with fault-related fluid flow is characterized by a very low-grade association composed by chlorite, epidote, albite, quartz and calcite. Chlorite thermometry indicates T-values in the range of 284 to 352 °C (average temperature of 323 °C) and no differences in mineral composition or T-values were observed among different cataclastic rock types. Mass balance and volume change calculations document that the major chemical mobility was observed in protocataclasite, whereas cataclasite and ultracataclasite show smaller changes. This suggests that fluid flow and chemical alteration post-dated the faulting, when the protocataclasite was relatively permeable and the cataclasite and ultracataclasite acted as a barrier for fluid flow having a very low permeability due to extreme grain size reduction during cataclasis.

  12. Mineralization stages of the unique shear zone-hosted "Felsit-type" Sn-polymetallic mineralization in the eastern Erzgebirge, Germany

    Science.gov (United States)

    Járóka, Tom; Seifert, Thomas

    2014-05-01

    The polymetallic cassiterite-bearing mineralization of the "Felsit-type" is located in the NW of the Freiberg mining district within the Großschirma area. The mineralization is hosted by metamorphic rocks of the Preßnitzer Group unit that form the most northeastern part of the Erzgebirge metamorphic core complex. This geological unit is in the Großschirma area predominantly composed of two-mica gneisses and mica schists, whereas intercalations of muscovite-gneiss ("red gneiss"), amphibolites and metacarbonates occur less commonly. These metamorphic rocks were deformed by several NE-SW striking fault zones. The hydrothermal Sn-bearing fluids migrated within shear zones that developed primarily at the contact between different lithotypes. The shear zones are characterized by strong pervasive metasomatic alterations which were triggered by small chlorite-cassiterite-quartz-sulfide-veins. The rock-forming minerals are strongly corroded and displaced by the ore and gangue minerals within the shear zones. The bulk geochemistry of selected drill core samples feature grades up to 0.28 wt. % Sn, 0.15 wt. % Cu, 300 ppm Pb, 140 ppm Zn, 1.1 wt. % F, 250 ppm Li, 820 ppm Rb, 90 ppm Cs, and 130 ppm W. Microscopic and geochemical studies of the samples show that the Sn-polymetallic mineralization of the "Felsit-type" can be distinguished into three different mineralization stages. The first one is dominated by chlorite and quartz. Cassiterite probably appears in two generations with different grain shapes: acicular (Freiberg Ag-Pb-Zn vein-ore district. The origin of the Sn-W mineralization in the Erzgebirge is still under debate.

  13. Thermal Analysis: A Complementary Method to Study the Shurijeh Clay Minerals

    Directory of Open Access Journals (Sweden)

    Golnaz Jozanikohan

    2015-06-01

    Full Text Available Clay minerals are considered the most important components of clastic reservoir rock evaluation studies. The Shurijeh gas reservoir Formation, represented by shaly sandstones of the Late Jurassic-Early Cretaceous age, is the main reservoir rock in the Eastern Kopet-Dagh sedimentary Basin, NE Iran. In this study, X-ray diffraction (XRD, X-ray fluorescence (XRF, scanning electron microscopic (SEM studies, and thermal analysis including differential thermal analysis (DTA, and thermogravimetric analysis (TGA techniques were utilized in the characterization of the Shurijeh clay minerals in ten representative samples. The XRF studies showed that silica and aluminum oxides are present quantities. The XRD test was then used to determine the mineralogical composition of bulk components, as well as the clay fraction. The XRD patterns indicated the presence of dominant amount of quartz and plagioclase, with moderate to minor amounts of alkali feldspar, anhydrite, carbonates (calcite and dolomite, hematite and clay minerals. The most common clays in the Shurijeh Formation were illite, chlorite, and kaolinite. However, in very few samples, glauconite, smectite, and mixed layer clay minerals of both illite-smectite and chlorite-smectite types were also recognized. The XRD results were quantified, using the elemental information from the XRF test, showing that each Shurijeh exhibited low to moderate amounts of clay minerals, typically up to 21%. The amount of illite, the most dominant clay mineral, reached maximum of 13.5%, while the other clay types were significantly smaller. Based on the use of SEM and thermal data, the results of the identification of clay minerals, corresponded with the powder X-ray diffraction analysis, which can be taken into account as an evidence of the effectiveness of the thermal analysis technique in clay typing, as a complementary method besides the XRD.

  14. Karakteristik mineralisasi epitermal di Daerah Taran, Hulu Kahayan, Kalimantan Tengah berdasarkan studi mikroskopis, X-Ray Diffraction (XRD, dan inklusi fluida

    Directory of Open Access Journals (Sweden)

    Danny Zulkifli Herman

    2014-06-01

    Full Text Available http://dx.doi.org/10.17014/ijog.vol1no3.20064Taran area is occupied predominantly by piroclastic rocks and locally intercalations of lenticular claystones and sandstones. The pyroclastic rocks are intruded by diorite, dacite and andesite, leading alteration and mineralization within the host rocks. Mineralization occurs as a vein type and is associated with a number of pervasive alteration types named respectively: quartz-illite- montmorillonite-kaolinite ± pyrite, quartz-illite ± pyrite, quartz-illite-chlorite ± pyrite and quartz- kaolinite-illite ± pyrite. On the other hand, a propylitic alteration also occurs within the andesite intrusion composed of calcite-epidote-chlorite-sericite-quartz ± pyrite. The mineralization is characterized by several zones of quartz stockwork containing gold and associated ore minerals of chalcopyrite, sphalerite, galena, pyrite and argentite. The quartz veins occurs as fi llings of structural openings in the form of milky quartz and amethyst with textures of sugary, comb, and dogteeth. Evaluation work on results of microscopic (petrography and mineragraphy, X-Ray Diffraction (XRD, and fl uid inclusion studies, and chemical analysis of entirely altered rock/quartz vein samples shows that the alteration and mineralization process were closely related to a change of hydrothermal fl uids, from near neutral into acid conditions at a temperature range of >290o – 100oC. The appearances of quartz variation indicate a relationship with repeated episodes of boiling in an epithermal system, as ground water mixed with hot vapor originated from a remained post-magmatic solution. Corresponding to a salinity of average 1,388 equiv.wt.% NaCl, it indicates that the ore minerals bearing quartz veins were deposited at a depth range of 640 – 1020 m beneath paleosurface.  

  15. Reduction of Surrogates for Escherichia coli O157:H7 and Salmonella during the Production of Nonintact Beef Products by Chemical Antimicrobial Interventions.

    Science.gov (United States)

    Ulbrich, Carson J; Lucia, Lisa M; Arnold, Ashley N; Taylor, T Matthew; Savell, Jeffrey W; Gehring, Kerri B

    2015-05-01

    The efficacy of chemical antimicrobials for controlling Escherichia coli O157:H7 and Salmonella during production of marinated nonintact beef products was evaluated using nonpathogenic surrogates. Boneless beef strip loins were inoculated with either approximately 5.8 or 1.9 log CFU/cm(2) (high and low inoculation levels, respectively) of nonpathogenic rifampin-resistant E. coli. Inoculated strip loins were chilled at 2°C for 24 h, vacuum packaged, and aged for 7 to 24 days at 2°C. After aging, strip loins received no treatment (control) or one of five antimicrobial spray treatments: 2.5% L-lactic acid (pH 2.6), 5.0% L-lactic acid (pH 2.4), 1,050 ppm of acidified sodium chlorite (pH 2.8), 205 ppm of peroxyacetic acid (pH 5.2), or tap water (pH 8.6). Mean application temperatures were 53, 26, 20, and 18°C for lactic acid, water, peroxyacetic acid, and acidified sodium chlorite treatments, respectively. Treated and control strip loins were vacuum tumbled in a commercial marinade. Samples were collected throughout the experiment to track the effects of antimicrobial treatment and processing on inoculated surrogates. For high-inoculation strip loins, the 5.0% L-lactic acid treatment was most effective for reducing surrogates on meat surfaces before marination, producing a 2.6-log mean reduction. Peroxyacetic acid treatment resulted in the greatest reduction of surface-located surrogate microorganisms in marinated product. Water treatment resulted in greater internalization of surrogate microorganisms compared with the control, as determined by enumeration of surrogates from cored samples. Producers of nonintact beef products should focus on use of validated antimicrobial sprays that maximize microbial reduction and minimize internalization of surface bacteria into the finished product.

  16. A possible source of water in seismogenic subduction zones

    Science.gov (United States)

    Kameda, J.; Yamaguchi, A.; Kimura, G.; Iodp Exp. 322 Scientists

    2010-12-01

    Recent works on the subduction megathrusts have emphasized the mechanical function of fluids contributing dynamic slip-weakening. Basalt-hosting fault zones in on-land accretionary complexes present several textures of seismic slip under fluid-assisted condition such as implosion breccia with carbonate matrix and decrepitation of fluid inclusion. In order to clarify initiation and evolution processes of such fault zones as well as possible source of fluid in the seismogenic subduction zone, we examined a mineralogical/geochemical feature of basaltic basement recovered by IODP Exp. 322 at C0012, that is a reference site for subduction input in the Nankai Trough. A total of 10 samples (about 4 m depth interval from the basement top) were analyzed in this study. XRD analyses indicate that all of the samples contain considerable amount of smectite. The smectite does not appear as a form of interstratified phase with illite or chlorite. Preliminary chemical analyses by EDS in TEM suggest that the smectite is trioctahedral saponite with Ca as a dominant interlayer cation. To determine the saponite content quantitatively, cation exchange capacity (CEC) of bulk samples was measured. The samples show almost similar CEC of around 30 meq/100g, implying that bulk rock contains about 30 wt% of saponite, considering a general CEC of 100 meq/100g for monomineralic saponite. Such abundance of saponite might be a result from intense alteration of oceanic crust due to sea water circulation at low temperature. Previous experimental work suggests that saponite might be highly hydrated (two to three water layer hydration form) at the seismogenic P-T condition. Hence, altered upper oceanic crust is a possible water sink in the seismogenic zone. The water stored in the smectite interlayer region will be expelled via smectite to chlorite transition reaction, that might contribute to the dynamic weakening of the seimogenic plate boundary between the basement basalt and overlying

  17. Geological and geochemical studies of the Shujiadian porphyry Cu deposit, Anhui Province, Eastern China: Implications for ore genesis

    Science.gov (United States)

    Wang, Shiwei; Zhou, Taofa; Yuan, Feng; Fan, Yu; White, Noel C.; Lin, Fengjie

    2015-05-01

    Most porphyry deposits in the world occur in magmatic arc settings and are related to subduction of oceanic plates. A small proportion of porphyry deposits occur in intracontinental settings, however they are still poorly understood. Shujiadian, a newly-discovered porphyry Cu deposit, is located in the Middle-Lower Yangtze River Valley metallogenic belt and belongs to the intracontinental class. The deposit has classic alteration zones defined by a core of potassic alteration and local Ca-silicate alteration, which is overprinted by a feldspar-destructive alteration zone and cut by veins containing epidote and chlorite. Wallrocks of the deposit are unreactive quartz-rich sedimentary rocks. Three main paragenetic stages have been recognized based on petrographic observations; silicate stage, quartz-sulfide stage, and sulfide-carbonate stage. Quartz + pyrite + chalcopyrite ± molybdenite veins, and quartz + chalcopyrite + pyrite veins of the quartz-sulfide stage contribute most of the copper, and chalcopyrite + chlorite ± pyrite ± pyrrhotite ± quartz ± illite veins of the sulfide-carbonate stage also contribute part of the copper; all the mineralized veins are associated with feldspar-destructive alteration. Investigations on the fluid inclusions in Shujiadian indicate that the ore-forming fluids had four evolutionary episodes: immiscibility and overpressure in the silicate stage, boiling in the quartz-sulfide stage and mixing with meteoric water in the sulfide-carbonate stage. Sulfur and strontium isotope studies suggest that ore metals were mainly derived from magmatic-hydrothermal fluids, and combined with our study of fluid inclusions, we infer that decompression, changes in oxygen fugacity and sulfur content were the main factors that caused Cu precipitation. Compared with porphyry deposits in magmatic arc settings, there are some differences in the ore-bearing rock, alteration, and the composition of ore-forming fluids.

  18. Co-evolution of monsoonal precipitation in East Asia and the tropical Pacific ENSO system since 2.36 Ma: New insights from high-resolution clay mineral records in the West Philippine Sea

    Science.gov (United States)

    Yu, Zhaojie; Wan, Shiming; Colin, Christophe; Yan, Hong; Bonneau, Lucile; Liu, Zhifei; Song, Lina; Sun, Hanjie; Xu, Zhaokai; Jiang, Xuejun; Li, Anchun; Li, Tiegang

    2016-07-01

    Clay mineralogical analysis and scanning electron microscope (SEM) analysis were performed on deep-sea sediments cored on the Benham Rise (core MD06-3050) in order to reconstruct long-term evolution of East Asian Summer Monsoon (EASM) rainfall in the period since 2.36 Ma. Clay mineralogical variations are due to changes in the ratios of smectite, which derive from weathering of volcanic rocks in Luzon Island during intervals of intensive monsoon rainfall, and illite- and chlorite-rich dusts, which are transported from East Asia by winds associated with the East Asian Winter Monsoon (EAWM). Since Luzon is the main source of smectite to the Benham Rise, long-term consistent variations in the smectite/(illite + chlorite) ratio in core MD06-3050 as well as ODP site 1146 in the Northern South China Sea suggest that minor contributions of eolian dust played a role in the variability of this mineralogical ratio and indicate strengthening EASM precipitation in SE Asia during time intervals from 2360 to 1900 kyr, 1200 to 600 kyr, and after 200 kyr. The EASM rainfall record displays a 30 kyr periodicity suggesting the influence of El Niño-Southern Oscillation (ENSO). These intervals of rainfall intensification on Luzon Island are coeval with a reduction in precipitation over central China and an increase in zonal SST gradient in the equatorial Pacific Ocean, implying a reinforcement of La Niña-like conditions. In contrast, periods of reduced rainfall on Luzon Island are associated with higher precipitation in central China and a weakening zonal SST gradient in the equatorial Pacific Ocean, thereby suggesting the development of dominant El Niño-like conditions. Our study, therefore, highlights for the first time a long-term temporal and spatial co-evolution of monsoonal precipitation in East Asia and of the tropical Pacific ENSO system over the past 2.36 Ma.

  19. Petrography and geochemical study of Nezam-Abad area, Southwest of Shazand, Arak

    Directory of Open Access Journals (Sweden)

    Robabeh Jafari

    2010-05-01

    Full Text Available Nezam-Abad area is located in southwest of Shazand (Arak which is a part of Sanandaj-Sirjan zone. Major intrusive rocks of Nezam-Abad are quartz diorite and minor amount of granodiorite. Leucogranitic, pegmatite dykes and quartz-tourmaline veins were intruded the quartz diorite. Quartz diorites are mainly composed of plagioclase, hornblende, biotite, quartz and pyroxene as major minerals. Major minerals of leucogranite are microcline, orthoclase, albite, quartz, biotite and muscovite. Accessory minerals consist of apatite, zircon, sphene, epidote, allanite, tourmaline and opaque. The presence of hydrous minerals like hornblende and biotite in these rocks indicate that the corresponding magma initially contained >3 wt% H2O (wet magma. The occurrences of garnet and andalusite minerals suggest assimilation process. Primary textures in these rocks are granular, granophyre, and poikilitic. Secondary textures are perthite, myrmekite, sericitization, chloritization and kaolinitization. Later hydrothermal activities and tectonic strains are factors for presence of perthite texture in leucogranite. K amount for sericitization of feldspars come from the K-feldspars and chloritization of biotite. Transformation of biotite to muscovite indicates the act of K rich fluid in later stages. On the basis of chemical analysis on the intrusive rocks, it is shown that the magma was calc-alkaline, metaluminous-peraluminous and medium-K to high-K. Study of major elements in Harker diagrams indicates Al2O3, FeO, Fe2O3 and CaO decrease with increasing of SiO2 and K2O and Na2O increase indicating that fractional crystallization may have played an important role in the formation of granitoid rocks from Nezam-Abad.

  20. Discovery of the Jabiluka uranium deposits, East Alligator River Region, Northern Territory of Australia

    International Nuclear Information System (INIS)

    The Jabiluka One and Two uranium deposits occur in Lower Proterozoic metasediments of the Cahill Formation. The observed part of the Cahill Formation exhibits four horizons which are favourable hosts for uranium mineralization. The host rocks are mainly chlorite and/or graphite schists and their brecciated equivalents which have undergone initial regional prograde metamorphism to amphibolite facies, then retrograde metamorphism to greenschist facies. Mineralization consists of uraninite, mainly filling open spaces and to a lesser extent in disseminated form. Chlorite alteration is intimately associated with the uranium mineralization. A portion of the Jabiluka Two deposit contains economic concentrations of gold. Although the deposits are generally stratabound, structural preparation appears to be the most significant ore control on a local scale. The Jabiluka case history illustrates an effective philosophy which was successful in exploration for stratabound uranium deposits in the East Alligator River Region. This philosophy encompassed the following points: (a) The value of regional appraisals in selection of a property; (b) The recognition of the detection limits of airborne radiometric surveys; (c) The importance of ground prospecting for low-order point-source radiometric anomalies which cannot be detected by airborne survey; (d) The importance of evaluating all anomalies and the flexibility to change priorities as further exploration results are obtained; (e) The necessity of establishing the controls on the mineralization before proceeding with further exploration; (f) The necessity of exploring extensions of favourable lithologies to test for periodicity of mineralization even where cover precludes surface expression; and (g) The desirability for modification of exploration techniques on different types of anomalies

  1. Environmental effect and genetic influence: a regional cancer predisposition survey in the Zonguldak region of Northwest Turkey

    Science.gov (United States)

    Kadir, Selahattin; Önen-Hall, A. Piril; Aydin, S. Nihal; Yakicier, Cengiz; Akarsu, Nurten; Tuncer, Murat

    2008-03-01

    The Cretaceous-Eocene volcano-sedimentary units of the Zonguldak region of the western Black Sea consist of subalkaline andesite and tuff, and sandstone dominated by smectite, kaolinite, accessory chlorite, illite, mordenite, and analcime associated with feldspar, quartz, opal-CT, amphibole, and calcite. Kaolinization, chloritization, sericitization, albitization, Fe-Ti-oxidation, and the presence of zeolite, epidote, and illite in andesitic rocks and tuffaceous materials developed as a result of the degradation of a glass shards matrix, enclosed feldspar, and clinopyroxene-type phenocrysts, due to alteration processes. The association of feldspar and glass with smectite and kaolinite, and the suborientation of feldspar-edged, subparallel kaolinite plates to fracture axes may exhibit an authigenic smectite or kaolinite. Increased alteration degree upward in which Al, Fe, and Ti are gained, and Si, Na, K, and Ca are depleted, is due to the alteration following possible diagenesis and hydrothermal activities. Micromorphologically, fibrous mordenite in the altered units and the presence of needle-type chrysotile in the residential buildings in which cancer cases lived were detected. In addition, the segregation pattern of cancer susceptibility in the region strongly suggested an environmental effect and a genetic influence on the increased cancer incidence in the region. The most likely diagnosis was Li-Fraumeni syndrome, which is one of the hereditary cancer predisposition syndromes; however, no mutations were observed in the p53 gene, which is the major cause of Li-Fraumeni syndrome. The micromorphology observed in the altered units in which cancer cases were detected may have a role in the expression of an unidentified gene, but does not explain alone the occurrence of cancer as a primary cause in the region.

  2. Magnitude and symmetry of seismic anisotropy in mica- and amphibole-bearing metamorphic rocks and implications for tectonic interpretation of seismic data from the southeast Tibetan Plateau

    Science.gov (United States)

    Ji, Shaocheng; Shao, Tongbin; Michibayashi, Katsuyoshi; Oya, Shoma; Satsukawa, Takako; Wang, Qian; Zhao, Weihua; Salisbury, Matthew H.

    2015-09-01

    We calibrated the magnitude and symmetry of seismic anisotropy for 132 mica- or amphibole-bearing metamorphic rocks to constrain their departures from transverse isotropy (TI) which is usually assumed in the interpretation of seismic data. The average bulk Vp anisotropy at 600 MPa for the chlorite schists, mica schists, phyllites, sillimanite-mica schists, and amphibole schists examined is 12.0%, 12.8%, 12.8%, 17.0%, and 12.9%, respectively. Most of the schists show Vp anisotropy in the foliation plane which averages 2.4% for phyllites, 3.3% for mica schists, 4.1% for chlorite schists, 6.8% for sillimanite-mica schists, and 5.2% for amphibole schists. This departure from TI is due to the presence of amphibole, sillimanite, and quartz. Amphibole and sillimanite develop strong crystallographic preferred orientations with the fast c axes parallel to the lineation, forming orthorhombic anisotropy with Vp(X) > Vp(Y) > Vp(Z). Effects of quartz are complicated, depending on its volume fraction and prevailing slip system. Most of the mica- or amphibole-bearing schists and mylonites are approximately transversely isotropic in terms of S wave velocities and splitting although their P wave properties may display orthorhombic symmetry. The results provide insight for the interpretation of seismic data from the southeast Tibetan Plateau. The N-S to NW-SE polarized crustal anisotropy in the Sibumasu and Indochina blocks is caused by subvertically foliated mica- and amphibole-bearing rocks deformed by predominantly compressional folding and subordinate strike-slip shear. These blocks have been rotated clockwise 70-90° around the east Himalayan Syntaxis, without finite eastward or southeastward extrusion, in responding to progressive indentation of India into Asia.

  3. Petrology and radiogeology of the Stripa pluton

    International Nuclear Information System (INIS)

    Both the quartz monzonite and the metavolcanic leptite which it intruded are strongly fractured. Two stages of fracture filling are evident; an earlier stage encompassing quartz, sericite, feldspar, epidote, and chlorite, and a later stage dominated by carbonate minerals. The Stripa quartz monozite is chemically and mineralogically distinct from other plutons in the region. Muscovite is the predominant mica in the quartz monzonite; biotite has been altered to chlorite, hornblende is absent, and accessory minerals are scarce. In contrast, in other plutons in the Stripa region, biotite and hornblende are prominent mafic minerals and accessory minerals are abundant. The Stripa quartz monzonite is also considerably more radioactive than the the leptite and other plutons in the region. Uranium and thorium abundances are both approx. 30 ppM, considerably higher than in normal granitic rocks where the thorium-to-uranium ratio generally exceeds 2. Potassium-argon dating of muscovite from the Stripa quartz monzonite indicates that this rock may be older, at 1691 million years than granitic rock of the neighboring Gusselby and Kloten massifs, whose ages, based on K-Ar dating of biotite, are respectively 1604 and 1640 m.y. Heat flow and heat productivity considerations show that although Stripa quartz monzonite contains high abundances of radioelements, the pluton has little efect on the regional heat flow. If it occurs in a layered plutonic setting, it is not more than 1.5 km thick; otherwise it may comprise a stock, dike, or border phase that is relatively small compared with the large granitic plutons exposed in the region

  4. Hydrophilic characteristics of soft rock in deep mines

    Institute of Scientific and Technical Information of China (English)

    Guo Hongyun; Li Bing; Zhang Yumei; Wang Xinbo; Zhang Feng

    2015-01-01

    A series of water absorption tests on dried soft rock have been conducted by the intelligent testing system for water absorption tests in deep soft rock, including tests of water absorption with and without pres-sure. The results show that the water absorbing capacity of rock with a certain pressure is larger than that of rock without pressure; however, the relationship between the water absorbing percentage and the time can be expressed by w(t)=a(1-e-bt). In bi-logarithmic coordinates, the hydrophilic relationship with time in tests with pressure could be characterized by linearity, while they present concave or convex in tests without pressure. Based on the hypothesis that each influential factor is irrelevant and they have a linear correlation with the water absorbing capacity, we calculated the weight coefficient of each factor according to experimental results under different conditions. The calculations demonstrate that the effec-tive porosity, content of smectite and kaolinite are all positively correlated with the water absorption capacity of rock;meanwhile, the fractal dimension of the effective pores presents a negative correlation with the water absorption capacity of rock. The water absorption capacity with pressure increases with increasing illite, chlorite and chlorite/smectite formation and a decrease in illite/smectite formation and the fractal dimension of the effective pores, while it is opposite in tests without pressure. The weight coefficient of smectite is smallest among positive factors, and the fractal dimension of the effective pores is the smallest amongst the negative factors.

  5. Clay minerals in surface sediments of the Pearl River drainage basin and their contribution to the South China Sea

    Institute of Scientific and Technical Information of China (English)

    LIU ZhiFei; Christophe COLIN; HUANG Wei; CHEN Zhong; Alain TRENTESAUX; CHEN JianFang

    2007-01-01

    Clay minerals have played a significant role in the study of the East Asian monsoon evolution in the South China Sea by being able to track oceanic current variations and to reveal contemporaneous paleoclimatic changes prevailing in continental source areas. As one of the most important rivers inputting terrigenous matters to the northern South China Sea, the Pearl River was not previously paid attention to from the viewpoint of clay mineralogy. This paper presents a detailed study on clay minerals in surface sediments collected from the Pearl River drainage basin (including all three main channels,various branches, and the Lingdingyang in the estuary) by using the X-ray diffraction (XRD) method.The results indicate that the clay mineral assemblage consists dominantly of kaolinite (35%-65%),lesser abundance of chlorite (20%-35%) and illite (12%-42%), and very scare smectite occurrences (generally <5%). Their respective distribution does not present any obvious difference throughout the Pearl River drainage basin. However, downstream the Pearl River to the northern South China Sea, the clay mineral assemblage varies significantly: kaolinite decreases gradually, smectite and illite increase gradually. Additionally, illite chemistry index steps down and illite crystallinity steps up. These variations indicate the contribution of major kaolinite, lesser illite and chlorite, and very scarce smectite to the northern South China Sea from the Pearl River drainage basin. The maximum contribution of clay minerals from the Pearl River is 72% to the northern margin and only 15% to the northern slope of the South China Sea. In both glacials and interglacials, kaolinite indicates that the ability of mechanical erosion occurred in the Pearl River drainage basin.

  6. Influences of petrographic parameters on technological properties of greywackes used for crushed stone production

    Science.gov (United States)

    Prikryl, Richard; Cermak, Martin; Krutilova, Katerina

    2014-05-01

    This study focuses on the influence of petrographic parameters on technological properties of greywackes. These sedimentary rocks make about 27 % of crushed stone market in the Czech Republic. Mainly in Moravia (eastern part of the Czech Republic), greywackes represent almost exclusive high quality aggregate. The behaviour of greywackes varies, however, from quarry to quarry. In this study, we have selected the most important deposits that cover major lithological variation of local greywackes. Studied greywackes were analysed for their petrographic parameters quantitatively (using image analysis of thin sections). The pore space characteristics were determined by using fluorescent dye - epoxy resin impregnated specimens. The studied rocks are composed of subangular and angular quartz grains, lithoclasts (stable rocks: quartzites, and unstable rocks: phylites, metaphylites, siltstones, slates, greywackes, and less frequently acid eruptive rocks), feldspars (orthoclas, microcline, plagioclase), and detrital micas. Detrital and authigenic chlorite has been found as well. The matrix which represents the largest volume of rock-forming components contains a mixture of sericite, chlorite, clay minerals, cements, and clasts in aleuropelitic size. Based on the microscopic examination, all studied rock types were classified as greywacke with fine- to medium-grained massive rock fabric. Only specimen from Bělkovice has shown partly layered structure. Alteration of feldspars and unstable rock fragments represents common feature. Diagenetic features included pressure dissolution of quartz clasts and formation of siliceous and/or calcite cements. Based on the experimental study of technological performance of studied greywackes and its correlation to petrographic features, the average size of clasts and volume of matrix make the driving factors affecting the LA values. The LA values decrease with the increasing of volume of matrix (R = 0.61) and with decreasing average grain

  7. Alteration and petrology of Intrusive Rocks associated with Gold Mineralization at Kuh-E-Zar Gold Deposit, Torbat-e-Heydaryeh

    Directory of Open Access Journals (Sweden)

    Alireza Mazloumi Bajestani

    2009-09-01

    Full Text Available Kuh- e -Zar gold deposit located 35 km west of Torbat-e-Heydaryeh, (Khorassan e- Razavi province, East of Iran. This deposit is a specularite-rich Iron oxide type (IOCG. This mine is situated within Khaf-Bardascan volcanic plutonic belt. Based on recent exploration along this belt, several IOCG type system plus Kuh-e-Zar deposit are discovered. In the study area, several type of tuff and lava having acid to intermediate composition are identified (upper Eocene. Oligo-Miocene granite, granodiorite, synogranite and monzonite intruded upper Eocene andesite-dacite-rhyolite. Intrusive rocks are meta-aluminous, medium to high-K series I-type. Based on spider diagram, intrusive rocks show enrichment in LILE = K, Th, Rb and depletion in HFSE = Nb, Sr, Ti. Based geochemistry of igneous rock, they formed in continental margin subduction zone. Propylitic (chlorite alteration is dominated and covers large area. Silicification is restricted only to mineralized zones. Argillic and albitization is found in certain location and cover small areas. The style of mineralization was controlled by the type and geometry of fault zones. Mineralization is found as vein, stockwork and breccias. Hypogene mineral Paragenesis include: specularite-quartz-gold-chlorite ± chalcopyrite ± pyrite ± galena ± barite. Secondary minerals formed due to oxidation are: goethite, limonite, lepidocrucite, Malachite, Azurite, Covelite, Cerucite, hydrocerucite, Pyrolusite and Smitsonite. In a few localities, chalcopyrite and minor pyrite and galena are found. Based on SEM analysis gold is present as electrum. Mineralization appeared in different type such as vein, stockwork and Hydrothermal breccia in strike sleep fault zone which are hidden inside volcano plutonic rocks. The average gold grade is between 3.02 ppm and ore reserve is estimated more than 3 million tons (cut off grade = 0.7 ppm.

  8. Uruguay geology contributions no. 3

    International Nuclear Information System (INIS)

    The recognised metals are regularly represented by Pb and Zn occurrences with the exception of Mina la Oriental (Cu) and Cerro Estela (Cu-Mo). All of them have as field rocks the volcano-sedimentary sequence of the Lavalleja Group. Three types of mineralizations are recognized: sulphurated amas linked to volcanism, limestones associated mineralizations, and structural controls. Moreover hidrothermalism explains many mineralizations, and is frequently linked to structural factors. Stratigraphy the mineralizations are located at different positions in the series. Apolonia and Chape at the base, Euritina, Reus and La Oriental are intermediate, Valencia Mines, Cu-Mo mineralization and the Mn occurrence at the topo At Apolonia the field rocks are basic metavulcanites. Three types of mineralizations are defined: dissemined Cu in the stockwerk made by chlorite and quartz, galene micro-amas in a epidotized metavulcanite and alteration of sulphurated chloritic levels. It can be classified as proximal sulphurated amas. At Chape the mineralization is fundamentally blende-galene-pyrite in a basic vulcanoclastites. Reus is found in black phyllites in a calcopelitic unit, being the mineralization formed by galene-pyrite. At Euritina the mineralization is made by malachite in a basic metavulcanite. Chape/Reus/Euritina are controled by structural factors associated to hidrothermalism of primary mineralizations. At Mine La Oriental the field rocks is a set of calcareous-chloritite-metamarges-jasper rocks. Mineralization is by Cu and belong to distal sulphurated amas. Valencia Mine is in dolomites with evidences 01emerging volcanic centers wich leed a dolomitic sedimentation. lt is mineralized with blende-galene. The mineralization Cu-Mo belongs to two types: the Mo is the result of periplutonic hidrothermalism and the Cu is associated to de volcano-sedimentary sequence. The Mn occurrences are associated to jasper levels and are constituted by pyrolusite and psilomelane.

  9. Systematic evaluation of satellite remote sensing for identifying uranium mines and mills.

    Energy Technology Data Exchange (ETDEWEB)

    Blair, Dianna Sue; Stork, Christopher Lyle; Smartt, Heidi Anne; Smith, Jody Lynn

    2006-01-01

    In this report, we systematically evaluate the ability of current-generation, satellite-based spectroscopic sensors to distinguish uranium mines and mills from other mineral mining and milling operations. We perform this systematic evaluation by (1) outlining the remote, spectroscopic signal generation process, (2) documenting the capabilities of current commercial satellite systems, (3) systematically comparing the uranium mining and milling process to other mineral mining and milling operations, and (4) identifying the most promising observables associated with uranium mining and milling that can be identified using satellite remote sensing. The Ranger uranium mine and mill in Australia serves as a case study where we apply and test the techniques developed in this systematic analysis. Based on literature research of mineral mining and milling practices, we develop a decision tree which utilizes the information contained in one or more observables to determine whether uranium is possibly being mined and/or milled at a given site. Promising observables associated with uranium mining and milling at the Ranger site included in the decision tree are uranium ore, sulfur, the uranium pregnant leach liquor, ammonia, and uranyl compounds and sulfate ion disposed of in the tailings pond. Based on the size, concentration, and spectral characteristics of these promising observables, we then determine whether these observables can be identified using current commercial satellite systems, namely Hyperion, ASTER, and Quickbird. We conclude that the only promising observables at Ranger that can be uniquely identified using a current commercial satellite system (notably Hyperion) are magnesium chlorite in the open pit mine and the sulfur stockpile. Based on the identified magnesium chlorite and sulfur observables, the decision tree narrows the possible mineral candidates at Ranger to uranium, copper, zinc, manganese, vanadium, the rare earths, and phosphorus, all of which are

  10. Contribution of Clay mineralogy of Bengal Fan deposits at 8°N for understanding of Himalayan provenance and environmental conditions

    Science.gov (United States)

    Huyghe, Pascale; France-Lanord, Christian; IODP Expedition 354 Scientists

    2016-04-01

    The IODP 354 expedition (February-March 2015) focused on the middle part of the Bengal Fan (8°N). Seven sites were drilled along a 320 km- long transect and provided good recovery and excellent data to study both provenance of the material from the Himalayan orogeny and palaeoceanography linked to the Asian monsoon. Neogene sediments consist of an alternation of rapidly deposited, silty to muddy turbidites (10-100 cm/kyr) forming levees of channels intercalated with minor slowly deposited hemipelagic clays (1-2 cm/kyr), which may be found over the whole investigated area. Thick interlevee sand sheet units also occur between channel levees. The turbiditic sand, silt and clay have mineralogical signatures very similar to those of the modern Ganges and Brahmaputra rivers and are therefore relevant for reconstructing time series of erosion, weathering, and changes in Himalayan sources regions. Hemipelagic calcareous clays may provide additional information on environmental conditions throughout the Himalayan basin. Preliminar shipboard XRD analysis revealed that the clayey assemblages of sediments are relatively constant through the Neogene. Turbidite clay assemblages are dominated by detrital illite and chlorite as observed in the modern Himalayan rivers, suggesting that erosion conditions were relatively steady over the last 25 Ma. Hemipelagic clay assemblages vary from 1) identical to the illite-chlorite rich clays of turbidites, characteristic for Himalayan rivers, to 2) smectite rich assemblages enriched in iron and depleted in potassium, representing either more extreme sorting of the same material or input from another source. Further detailed investigation using decomposition of X-Ray diffraction (XRD) patterns reveals much more complex clay assemblages, especially great quantities of mixed-layers, the quantity and mineralogy of which varies and differs in the three depositional units as determined by turbidites levees, hemipelagic clayey beds and interlevees

  11. Geomorphological stability of Permo-Triassic albitized profiles - case study of the Montseny-Guilleries High (NE Iberia)

    Science.gov (United States)

    Parcerisa, D.; Casas, L.; Franke, C.; Gomez-Gras, D.; Lacasa, G.; Nunez, J. A.; Thiry, M.

    2010-05-01

    Massif paleoalteration profiles (≥ 200 m) occur in the upper parts of the Montseny-Guilleries High (NE Catalan Coastal Ranges). The profiles consist of hard albitized-chloritized-hematized facies in the lower part and softer kaolinized-hematized facies in the upper part of the section. Preliminary paleomagnetic data show Triassic ages for both, the albitized and the kaolinized parts, and point to a surficial formation altered under oxidising conditions. Similar paleoalteration profiles have already been described and dated to Triassic ages elsewhere in Europe [Schmitt, 1992; Ricordel et al., 2007; Parcerisa et al., 2009]. These Permian-Triassic alterations are following a succession of different mineral transformations from the top to the base of the profile: 1) Red facies are defined by an increase in the amount and size of haematite crystals leading to the red colour of the rocks. The increase on haematite content is pervasively affecting the whole rock and is accompanied by the kaolinitization of the feldspars. 2) Pink facies: here, the granite shows an uniform pink colouration, which is mainly due to the albitization of the primary Ca-bearing plagioclases, accompanied by a precipitation of minute haematite, sericite, and calcite crystals inside the albite. Additionally primary biotite is fully chloritized. The pink granites are much more resistant to the present-day weathering than the "unaltered" facies at the base of the profile. 3) Spotted facies is characterized by a partial alteration of the rock, which caused a pink-screened aspect to the rock. The alteration developed along the fractures and is less well developed or absent in the non-fractured zones. In the pink-screened facies, the plagioclases are partially albitized and contain numerous hematite inclusions. Biotites are usually almost entirely chloritized. 4) Unaltered facies: These granites are coloured white to greyish, containing plagioclase and K-feldspar that do not show any trace of

  12. The Rožná uranium deposit (Bohemian Massif, Czech Republic): shear zone-hosted, late Variscan and post-Variscan hydrothermal mineralization

    Science.gov (United States)

    Kříbek, Bohdan; Žák, Karel; Dobeš, Petr; Leichmann, Jaromír; Pudilová, Marta; René, Miloš; Scharm, Bohdan; Scharmová, Marta; Hájek, Antonín; Holeczy, Daniel; Hein, Ulrich F.; Lehmann, Bernd

    2009-01-01

    Three major mineralization events are recorded at the Rožná uranium deposit (total mine production of 23,000 t U, average grade of 0.24% U): (1) pre-uranium quartz-sulfide and carbonate-sulfide mineralization, (2) uranium, and (3) post-uranium quartz-carbonate-sulfide mineralization. (1) K-Ar ages for white mica from wall rock alteration of the pre-uranium mineralization style range from 304.5 ± 5.8 to 307.6 ± 6.0 Ma coinciding with the post-orogenic exhumation of the Moldanubian orogenic root and retrograde-metamorphic equilibration of the high-grade metamorphic host rocks. The fluid inclusion record consists of low-salinity aqueous inclusions, together with H2O-CO2-CH4, CO2-CH4, and pure CH4 inclusions. The fluid inclusion, paragenetic, and isotope data suggest that the pre-uranium mineralization formed from a reduced low-salinity aqueous fluid at temperatures close to 300°C. (2) The uraniferous hydrothermal event is subdivided into the pre-ore, ore, and post-ore substages. K-Ar ages of pre-ore authigenic K-feldspar range from 296.3 ± 7.5 to 281.0 ± 5.4 Ma and coincide with the transcurrent reorganization of crustal blocks of the Bohemian Massif and with Late Stephanian to Early Permian rifting. Massive hematitization, albitization, and desilicification of the pre-ore altered rocks indicate an influx of oxidized basinal fluids to the crystalline rocks of the Moldanubian domain. The wide range of salinities of fluid inclusions is interpreted as a result of the large-scale mixing of basinal brines with meteoric water. The cationic composition of these fluids indicates extensive interaction with crystalline rocks. Chlorite thermometry yielded temperatures of 260°C to 310°C. During this substage, uranium was probably leached from the Moldanubian crystalline rocks. The hydrothermal alteration of the ore substage followed, or partly overlapped in time, the pre-ore substage alteration. K-Ar ages of illite from ore substage alteration range from 277.2 ± 5.5 to

  13. Statistical analysis of results from the quantitative mapping of fracture minerals in Forsmark. Site descriptive modelling - complementary studies

    Energy Technology Data Exchange (ETDEWEB)

    Loefgren, Martin (Niressa AB, Norsborg (Sweden)); Sidborn, Magnus (Kemakta Konsult AB, Stockholm (Sweden))

    2010-12-15

    Within the Forsmark site investigation campaign, quantitative mapping of different fracture minerals has been performed. This has been done by studying fracture surfaces of drill core sections from many different boreholes at the Forsmark site /Eklund and Mattsson 2009/. The drill core mapping was focused on the rock in the vicinity of flow anomalies detected by the Posiva Flow Log (PFL). The quantitative mapping was performed only on open fractures. The fracture minerals that were mapped are calcite, chlorite, clay minerals (as a group), hematite, and pyrite. In this present report, data from the quantitative mineral mapping campaign are refined, sorted into different data subsets, and analysed by parametric and non-parametric statistical methods. The data subsets are associated with 21 different rock volumes, representing different elevations, rock domains, fracture domains, and groups of deformation zones. In total 2,071 fractures were mapped at the site, and the most frequent mineral was calcite. Its amount could be quantitatively estimated in 32% of the mapped fractures. Of the other minerals, chlorite was quantitatively estimated in 24%, clay minerals in 11%, pyrite in 10%, and hematite in 0.4% of the mapped fractures. For fractures where the averaged fracture mineral thickness, d{sub mean} [mm], and visible coverage, C{sub vis} [%], could be quantitatively estimated, the following arithmetic means were found: calcite = 0.11 mm and 18%, chlorite = 0.22 mm and 38%, clay minerals = 0.14 mm and 40%, pyrite = 2.3 mum and 0.5%, hematite = 19 mum and 14%. These quantities are based on visual inspection of fracture surfaces and do not include the contribution from non-consolidated fracture fillings. It is shown that there is significant spatial variability of d{sub mean} and C{sub vis} within the examined rock volumes. Furthermore, the non-parametric analyses indicate that there are differences in d{sub mean} and C{sub vis} between the different rock volumes. Even

  14. Statistical analysis of results from the quantitative mapping of fracture minerals in Laxemar. Site descriptive modelling - complementary studies

    Energy Technology Data Exchange (ETDEWEB)

    Loefgren, Martin (Niressa AB, Norsborg (Sweden)); Sidborn, Magnus (Kemakta Konsult AB, Stockholm (Sweden))

    2010-12-15

    Within the Laxemar site investigation campaign, quantitative mapping of different fracture minerals has been performed. This has been done by studying fracture surfaces of drill core sections from many different boreholes at the Laxemar site /Eklund and Mattsson 2008/. The drill core mapping was focused on the rock in the vicinity of flow anomalies detected by the Posiva Flow Log (PFL). The quantitative mapping was performed only on open fractures. The fracture minerals that were mapped are calcite, chlorite, clay minerals (as a group), hematite, and pyrite. In this present report, data from the quantitative mineral mapping campaign are refined, sorted into different data subsets, and analysed by parametric and non-parametric statistical methods. The data subsets are associated with 17 different rock volumes, representing different elevations, rock domains, fracture domains, and groups of deformation zones. In total 1,852 fractures were mapped at the site, and the most frequent mineral was calcite. Its amount could be quantitatively estimated in 51% of the mapped fractures. Of the other minerals, chlorite was quantitatively estimated in 46%, pyrite in 19%, clay minerals in 16%, and hematite in 0.05% of the mapped fractures. For fractures where the averaged fracture mineral thickness, d{sub mean} [mm], and visible coverage, C{sub vis} [%], could be quantitatively estimated, the following arithmetic means were found: calcite = 0.25 mm and 22%, chlorite = 0.29 mm and 41%, pyrite =1.3 mum and 0.2%, and clay minerals = 0.15 mm and 35%. These quantities are based on visual inspection of fracture surfaces and do not include the contribution from non-consolidated fracture fillings. It is shown that there is significant spatial variability of d{sub mean} and C{sub vis} within the examined rock volumes. Furthermore, the non-parametric analyses indicate that there are differences in d{sub mean} and C{sub vis} between the different rock volumes. Even so, the differences are

  15. The Freyenstein Shear Zone - Implications for exhumation of the South Bohemian Batholith (Moldanubian Superunit, Strudengau, Austria)

    Science.gov (United States)

    Griesmeier, Gerit; Iglseder, Christoph; Konstantin, Petrakakis

    2016-04-01

    The Moldanubian superunit is part of the internal zone of the Variscan Orogen in Europe and borders on the Saxothuringian and Sudetes zones in the north. In the south, it is blanketed by the Alpine foreland molasse. Tectonically it is subdivided into the Moldanubian Nappes (MN), the South Bohemian Batholith (SBB) and the Bavarian Nappes. This work describes the ~ 500 m thick Freyenstein shear zone, which is located at the southern border of the Bohemian Massif north and south of the Danube near Freyenstein (Strudengau, Lower Austria). The area is built up by granites of Weinsberg-type, which are interlayered by numerous dikes and paragneisses of the Ostrong nappe system. These dikes include medium grained granites and finegrained granites (Mauthausen-type granites), which form huge intrusions. In addition, smaller intrusions of dark, finegrained diorites und aplitic dikes are observed. These rocks are affected by the Freyenstein shear zone und ductily deformed. Highly deformed pegmatoides containing white mica crystals up to one cm cut through the deformed rocks and form the last dike generation. The Freyenstein shear zone is a NE-SW striking shear zone at the eastern edge of the SBB. The mylonitic foliation is dipping to the SE with angles around 60°. Shear-sense criteria like clast geometries, SĆ structures as well as microstructures show normal faulting top to S/SW with steep (ca. 50°) angles. The Freyenstein shear zone records a polyphase history of deformation and crystallization: In a first phase, mylonitized mineral assemblages in deformed granitoides can be observed, which consist of pre- to syntectonic muscovite-porphyroclasts and biotite as well as dynamically recrystallized potassium feldspar, plagioclase and quartz. The muscovite porphyroclasts often form mica fishes and show top to S/SW directed shear-sense. The lack of syntectonic chlorite crystals points to metamorphic conditions of lower amphibolite-facies > than 450° C. In a later stage fluid

  16. Mineralogía y génesis de las arcillas de la Unidad de Almarchal (series flysch del Campo de Gibraltar. S de España

    Directory of Open Access Journals (Sweden)

    Carrasco, F.

    1990-08-01

    Full Text Available A study of the fine fraction of the Almarchal unit (Campo de Gibraltar flysch series revealed several very characteristic mineralogical associations, closely associated with the types of the rocks in this area. 1. Kaolinite-(illite-swelling minerals, characteristically associated with the lutitic leves, clearly preponderate in this unit.2. Illite-chlorite, a well-developed association found only in calcareous rocks. 3. Chlorite and/or berthierine, a characteristic association of silicified levels. Thus, it is possible to determine a group of levels, typically turbiditic and another group of lutitic levels, probably hemipelagic deposits, in which the content of organic material is noteworthy. The control of the mineralogic evolution by lithology is a result of different permeabilities in alternating levels. In calcareous beds the mineralogy of the fine fraction could result from the diagenetic degradation of aluminosilicates. Diagenetic Fe-rich chlorites, preferably developed in siliceous rocks resulting from the evolution of detrital kaolinites. In lutitic beds, two types of mineral constituents are mixed: Typically detrital mineral species (like kaolinite and diagenetic materials (swelling minerals. The abundance of organic matter in these levels can be related with oceanic anoxic events in Cretaceous time in North Atlantic basins.El estudio de la fracción fina de la Unidad de Almarchal (series flysch del Campo de Gibraltar ha permitido poner de manifiesto varias asociaciones mineralógicas relacionadas estrechamente con los tipos litológicos presentes: 1. Caolinita-(ilita-minerales hinchables, asociación propia de los niveles lutíticos, claramente dominantes en esta Unidad.2. Bita-clorita, asociación bien desarrollada en las rocas calcáreas.3. Clorita y/o bertierina, minerales que caracterizan a los niveles silicificados.En la mayor parte de las secuencias es posible, por lo tanto, determinar una serie de niveles típicamente turbid

  17. The geological and metallogenic setting of stratabound carbonate-hosted Zn-Pb mineralizations in the West Asturian Leonese Zone, NW Spain

    Science.gov (United States)

    Tornos, F.; Ribera, F.; Shepherd, T. J.; Spiro, B.

    1996-01-01

    Several carbonate-hosted stratabound zinc-lead ores in the Ponferrada-Caurel area (NW Spain) are hosted by the Lower to Middle Cambrian Vegadeo Formation. Two clearly distinct groups of mineralizations occur in different stratigraphic positions. The stratiform disseminated ore is located in the Lower Member as irregular and millimetre-thick layers of sphalerite and galena replacing earlier pyrite. The lack of hydrothermal alteration and the heavy C., O and S isotopic signatures suggest that this ore is of premetamorphic origin, the sulphur and fluids being derived from the host carbonates. The more likely source of the sulphide is the abiogenic thermal reduction of sulphate derived from sulphate beds intercalated with the carbonates. The second group of mineralizations is located at the top of the Vegadeo Fm, always along its contact with the overlaying shales and sandstones of the Cabos Series. This group is economically more important and include three styles of strata-bound mineralizations. The more common one is the ‘silica ore’, a hydrothermal rock that traces the contact between the carbonate and the detrital rocks along more than 50 km. Locally, a ‘carbonate-rich ore’ is found along the contact between the silica ore and the Vegadeo Fm. Laterally to these rocks, there are large bodies of the ≪breccia ore≫, made up of sulphides and calcite in a matrix of chlorite. The ore assemblage is composed of sphalerite and galena with minor amounts of chalcopyrite and pyrite. Co-Ni-As sulphides, bismuthinite, tetrahedrite and Pb-Bi sulphosalts are also found as trace minerals. The geological relationships and the isotopic signatures suggest that the three ores are synchronous and of late Hercynian age. They are interpreted as linked with a tectonically driven fluid flow along the stratigraphic contact between the carbonate and the detrital rocks. The model of ore genesis involves the circulation of fluids in likely equilibrium with the detrital rocks that

  18. Architecture of a dolostone-hosted brittle-ductile fault: effects of the interplay between weakening and strain localization mechanisms

    Science.gov (United States)

    Torgersen, Espen; Viola, Giulio

    2014-05-01

    Carbonates can remain mechanically strong under most upper crustal conditions, which is testified by the considerable number of moderate to large earthquakes associated with slip on carbonate-hosted faults. Yet, under certain environmental conditions carbonates decompose into mechanically weak minerals, with major consequences for a fault's rheological behavior. We combine structural analysis with petrography, geochemistry and K-Ar dating of synkinematic illite to investigate the processes that control the initial weakening of dolostone and the subsequent strain localization within brittle-ductile faults, aiming at better understanding why some faults remain strong and seismogenic, while others evolve into weak, creeping systems. The Kvenklubben fault (KF) is exposed in the Repparfjord Tectonic Window, northern Norway and is part of a compressional imbricate stack formed during Caledonian SE-directed nappe emplacement. It dips c. 40° to the NW and juxtaposes greenschist facies metabasalts in the hanging wall against chert-bearing meta-dolostones. The fault core is about 2.5 m thick and is composed of talc-bearing calc-phyllonites at the base and chlorite phyllonites at the top. Kinematic indicators show top-to-the SE thrusting, but also late localized top-to-the NNW extensional reactivation. The complex internal architecture of the fault results from multiple faulting episodes. K-Ar ages document that slip initiated in the lower part of the fault core and propagated upwards. The uppermost part of the fault was reactivated as a normal fault in the Mesozoic. Chlorite geothermometery shows that initial localization at the base of the fault core took place at 180-250 °C, whereas later peak Caledonian deformation occurred under higher temperatures (300-350 °C). This is also supported by sub-grain rotation recrystallization of quartz. Within the footwall dolostones an intraformational thrust fault developed sub-parallel to the main KF strand. Its fault core is

  19. Mineralogical investigations of the interaction between iron corrosion products and bentonite from the NF-PRO Experiments (Phase 1)

    Energy Technology Data Exchange (ETDEWEB)

    Milodowski, A.E.; Cave, M.R.; Kemp, S.J.; Taylor, B.H.; Vickers, B.P.; Green, K.A.; Williams, C.L.; Shaw, R.A. (British Geological Survey (United Kingdom))

    2009-01-15

    observations, potentially indicating the early stages of conversion of montmorillonite towards an iron-rich clay mineral as a result of interaction with Fe released by the corrosion of iron or steel. The cation exchange capacity (CEC) and exchangeable cation chemistry of the bentonite was also seen to be subtly affected by interaction with Fe. Bentonite from within the zones where corroded steel wires were present displayed a slightly reduced CEC, and depletion in exchangeable Ca and Na, and an increase in exchangeable Fe. This is consistent with at least partial displacement of the interlayer cations in montmorillonite by Fe. The loss in CEC might also correlate with a partial conversion of the montmorillonite to chlorite, which is tentatively suggested from the XRD analyses. Fe released from the corroding steel was also observed to displace Ca2+ from the interlayer cation sites in the montmorillonite component. This was manifested by the marked concentration of Ca at the interface with the corroding metal and along the leading edges of 'fronts' of Fe diffusing into the bentonite matrix. The displaced Ca was seen to have re-precipitated as aragonite. The petrographical observations show that the bentonite within the alteration zone, that has reacted with and is enriched by Fe, has a tendency to show significantly reduced shrinkage on sample drying in comparison to the background unaltered bentonite. Conversely, this would suggest that the reacted and altered clay will also have less ability to swell on hydration with water. This behaviour might be consistent with the partial conversion of the montmorillonite to an iron rich dioctahedral smectite such as nontronite, or to non-swelling clay mineral such as chlorite (or chlorite-smectite mixed-layer clay). If this is the case, then this may have important implications for the long-term behaviour of bentonite seals around radioactive waste canisters made of iron or steel

  20. Geochemical, microtextural and petrological studies of the Samba prospect in the Zambian Copperbelt basement: a metamorphosed Palaeoproterozoic porphyry Cu deposit.

    Science.gov (United States)

    Master, Sharad; Mirrander Ndhlovu, N.

    2015-04-01

    , including potassic (biotite+sericite+ quartz), propylitic (clinozoisite+chlorite+saussuritized plagioclase), phyllic (sericite+quartz+ pyrite+hydromuscovite/illite) and argillic (kaolinite+chlorite+dolomite) alteration. The clays were identified with XRD. All the rocks show penetrative deformational textures and fabrics. Our textural studies show that phyllic zone pyrite crystals have quartz-rich pressure shadows, and they predate all phases of deformation. Similarly, in the potassic zone, fracture-controlled biotite stringers in particular orientations are deformed, and partly replaced by chlorite, again showing their pre-deformational, pre-metamorphic origin. Copper sulfide-bearing quartz veinlets are deformed. Many of the alteration assemblages containing biotite or sericite have been deformed into crenulated schists, showing that they were formed early in the deformation history. Coupled with the dating of a Samba metavolcanic rock at 1964±12 Ma (Rainaud et al., 2005, JAES, 42, 1-31), we regard the Samba deposit as a metamorphosed Palaeoproterozoic porphyry-type Cu deposit, which has undergone deformation, and retrograde metamorphism of its alteration assemblages, during the Neoproterozoic Lufilian Orogeny, followed by post-tectonic cooling, which occurred throughout the Copperbelt at about 480±20 Ma. Samba, together with the Mkushi deposits, is part of a long-lived (>100 Ma) Palaeoproterozoic porphyry-Cu province in the Zambian Copperbelt basement, and ore genetic theories for the Copperbelt mineralization must now seriously take this into account.

  1. Mineralogy and Colosation of Oil-Green Jadeite Jade%“油青种”翡翠的矿物学特征及颜色成因

    Institute of Scientific and Technical Information of China (English)

    殷科; 田键; 马遇伯; 吴钰; 汪洋

    2014-01-01

    采用X射线衍射、红外吸收光谱及扫描电镜等现代测试方法,对“油青种”翡翠的矿物学特征及颜色成因进行了深入研究。X射线衍射分析结果显示,“油青种”翡翠“肉”的矿物组成为较纯的硬玉,而“皮”由硬玉、绿泥石及纤蛇纹石等三种矿物组成。红外吸收光谱分析所揭示的矿物组成与X射线衍射较为一致,同时发现“油青种”翡翠“肉”及“皮”具有~2956,~2919和~2850 cm -1等三个典型有机质的特征吸收峰。“油青种”翡翠“肉”中硬玉呈现明显的柱状,结晶程度明显好于“皮”中的硬玉,但“皮”中硬玉比“肉”中硬玉明显富含Mg ,说明“皮”中硬玉发生过强烈的水/岩反应。纤蛇纹石仅在“油青种”翡翠的“皮”中出现,晶面呈现明显的弯曲状。在“油青种”翡翠“肉”的裂隙处及“皮”中均发现片状绿泥石的存在,可能为“油青种”翡翠致色的主要原因。形成于还原性水/岩反应的绿泥石,会吸附或者包裹一定量的有机质,导致“油青种”翡翠出现有机质的特征吸收峰。%Mineralogy and coloration of oil-green jadeite jade were investigated using X-Ray diffraction (XRD) ,Fourier trans-form infrared absorption spectroscopy (FTIR) and scanning electron microscopy (SEM ) .XRD results show that “flesh” of oil-green jadeite jade is mainly composed of relatively pure jadeite ,whereas the“skin”of which is dominated by jadeite ,chlorite and chrysotile .The mineral constituents revealed by FTIR are fairly consistent with XRD . Three typical adsorption peaks of~2 956 ,~2 919 and ~2 850 cm -1 related to organic matters occurred in both “flesh”and“skin”of oil-green jadeite jade .Jade-ite in“flesh”exhibits an obvious columnar growth and has a better crystallinity than that of “skin” .However ,jadeite in“skin”is richer in magnesium than that of

  2. Gemmological and mineralogical investigations and genesis of the kammererite from the Keşiş (Erzincan) and Kop (Erzurum) mountains

    Science.gov (United States)

    Hatipoğlu, Murat; Oğuzer, Melis Buşra; Baki Buzlu, H.

    2013-08-01

    Even though there are many chromitite deposits in Turkey, the most productive chromitite deposits including chromian clinochlore and chromian are present in the eastern Anatolia region. Kammererite (chromian clinochlore), in essence, is one of the rarest clinochlore minerals as a sub-variety of large family of the chlorite minerals. Even though it is the monoclinic IIb-2 polytype, with symmetry C2/m, which is one of the most abundant regular-stacking one-layer chlorites occurring in nature, the crystallization of chromian clinochlore is less abundance. Hence, gem-quality magenta colored kammererite which may be formulized as [Mg5(Al, Cr, Fe)2Si3O10(OH)8] with reference to the abundance of the main oxides in the XRF bulk analyses, is only found in Turkey worldwide. Therefore, they are called Turkish kammererite. Beside of the mineral kammererite, the minerals uvarovite, magnesite, chromian spinel, chlorite and some garnets are also present in the paragenesis. Geological field observations and data in the region reveal that the kammererite specimens are crystallized as remobilized-origin on a chromitite matrix, deposited in the podiform-type chromitite ore deposits, and surrounded by the peridotitic and harzburgitic ultrabasic rocks. Thus, it can be stated that this rare mineral formation is derived from the secondary components of the hydrothermal alteration of the principle amphibole, pyroxene and biotite minerals in the surrounding peridotitic and harzburgitic (partially serpentinitic) rocks where they are embedded throughout the Northeastern Ophiolitic Belt comprising the Keşiş and Kop Mountains in the Eastern Anatolia region of Turkey. In this study, unique loose Turkish kammererite crystals were the first time investigated as both mineralogically and gemmologically. Accordingly, the well-known some further spectroscopic analytical methods were used to characterize and identify in detail for provenance and genesis. Firstly, as a structural characterization, in

  3. Facies metamórficas y edades relativas de las rocas del extremo oriental del Brazo Huemul, provincia de Neuquén Metamorphic facies and relative ages of rocks on the eastern part of Brazo Huemul, Neuquén province

    Directory of Open Access Journals (Sweden)

    M.F. Gargiulo

    2006-06-01

    exposed in the study area are mainly of tonalitic composition and have been correlated with the Subcordilleran Patagonian Batholith because they are crosscut by two different types of dikes. One group of dikes shows an albite - chlorite - epidote - cummingtonite/ grunerite - hornblende mineral assemblage as a consequence of a thermal metamorphic event transitional between albite - epidote hornfels facies and hornblende hornfels conditions. This process has been attributed to the emplacement of the Cordilleran Patagonian Batholith of Cretaceous age. Because of this, the hornfels dikes were correlated with Montes de Oca Formation. The other group of dikes shows a chlorite + pumpellyite + laumontite + chlorite/esmectite + iron oxides assemblage indicating metamorphism in zeolite facies of high temperature or, sometimes shows propilitic alteration and these dikes have been correlated with the Ventana Formation. The differences between these two types of dikes allow the discussion of the relative age of the tonalitic rocks that host them. In this paper it is proposed that this tonalitic body is of Low to Middle Jurassic age.

  4. Systematics of hydrothermal alteration at the volcanic-hosted Falun Zn-Pb-Cu-(Au-Ag) deposit - implications for ore genesis, structure and exploration in a 1.9 Ga ore district, Fennoscandian Shield, Sweden

    Science.gov (United States)

    Kampmann, Tobias C.; Jansson, Nils J.; Stephens, Michael B.; Majka, Jarosław

    2016-04-01

    The Palaeoproterozoic, volcanic-hosted Falun Zn-Pb-Cu-(Au-Ag) sulphide deposit was mined for base and precious metals during several centuries, until its closure in 1992. The deposit is located in a 1.9 Ga ore district in the Bergslagen lithotectonic unit, Fennoscandian Shield, south-central Sweden. Both the ores and their host rock underwent polyphase ductile deformation, and metamorphism under amphibolite facies and later retrograde conditions at 1.9-1.8 Ga (Svecokarelian orogenic system). This study has the following aims: (i) Classify styles and intensities of alteration in the hydrothermally altered zone at Falun; (ii) identify precursor rocks to hydrothermally altered rocks and their spatial distribution at the deposit; (iii) evaluate the chemical changes resulting from hydrothermal alteration using mass change calculations; and (iv) assess the pre-metamorphic alteration assemblages accounting for the observed metamorphic mineral associations in the altered rocks at Falun. Results will have implications for both the ore-genetic and structural understanding of the deposit, as well as for local and regional exploration. Metamorphic mineral associations in the altered rocks include biotite-quartz-cordierite-(anthophyllite) and, more proximally, quartz-anthophyllite-(biotite-cordierite/almandine), biotite-cordierite-(anthophyllite) and biotite-almandine-(anthophyllite). The proximal hydrothermally altered zone corresponds to intense chlorite-style alteration. Subordinate dolomite or calcite marble, as well as calc-silicate (tremolite, diopside) rocks are also present at the deposit. Metavolcanic rocks around the deposit are unaltered, weakly sericitized or sodic-altered. Immobile-element (e.g. Zr, TiO2, Al2O3, REE) systematics of the silicate-rich samples at and around the deposit suggest that the precursors to the hydrothermally altered rocks at Falun were predominantly rhyolitic in composition, dacitic rocks being subordinate and mafic-intermediate rocks

  5. A-type and I-type granitoids and mylonitic granites of Hassan Salaran area of SE Saqqez, Kurdistan, Iran

    Science.gov (United States)

    Abdullah, Fakhraddin Mohammad; Saeed Ahmad, Sheler

    2014-05-01

    event. The mylonitic granites are elongated masses with a NE-SW trend and their contacts with the A-type and I-type granitoids are fault contact. Hand specimens have a layered appearance with green bands made from chlorite and epidote and grey to white bands with quartz and feldspar. These rocks contain plagioclase, quartz and orthoclase under the microscope. Also fine-grained minerals such as quartz, sericite, epidote, chlorite and opaque minerals make the groundmass wrapping the porphyroclasts. Pressure shadows around porphyroclasts of plagioclase and quartz and crystallization of fine-grained quartz and sericite in these places along with intense alteration of plagioclase to epidote and sericite, existence of quartz with different sizes, andaluse extinction in quartz crystals, and elongation of chlorites, resulted from dynamic recrystallisation of biotites all indicate effect of stresses on the rocks. Considering the similar mineralogical composition of the mylonitic rocks with I-type granitoid, it could be concluded that the granodioritic magma, after intrusion and solidification, is changed to mylonite in a shear zone due to tectonical forces.

  6. The influence of natural trace element distribution on the mobility of radionuclides. The exemple of nickel in a clay-rock

    International Nuclear Information System (INIS)

    Highlights: • Ni distribution in the Callovian–Oxfordian formation (Bure, France) was investigated. • Ni is mainly borne by pyrite (Py), chlorite and organic matter (OM). • 63Ni sorption on clays is hindered by competition with trace metals (e.g. Zn, Co). • Additional sorption mechanisms are necessary to explain 63Ni long-term retention. • These may be isotopic exchange and structural incorporation (into calcite, OM or Py). - Abstract: The natural distribution of nickel (Ni) in the Callovian–Oxfordian clay-rich rock of Bure (France) was investigated, together with that of cobalt (Co), zinc (Zn) and lead (Pb). The most Ni-enriched phases are pyrite (∼400 × 10−6 g g−1 Ni), sphalerite (∼300 × 10−6 g g−1), chlorite (∼285 × 10−6 g g−1), organic matter (∼300 × 10−6 g g−1), muscovite (100–200 × 10−6 g g−1) and possibly carbonate minerals (mainly calcite and minor dolomite, ∼10 × 10−6 g g−1). Despite their high abundance (up to ∼80% in the upper part of the formation), carbonate minerals are quantitatively a minor Ni reservoir; most of the Ni is borne by chlorite and pyrite, which are minor mineral phases. Co and Ni have a similar distribution, whereas Pb and Zn have partly different reservoirs (e.g. sphalerite – ZnS). In parallel, the equilibrium between rock and pore water was investigated, and importance of pyrite (or reduced sulfur minerals) as Ni reservoir in the formation was confirmed from an in situ experiment perturbed by oxidation processes. Under unperturbed conditions (laboratory kinetics experiments and in situ pore water sampling), Ni solubility ranges from ∼0.2 to 1 × 10−6 mol L−1. The rock sorption capacities with regards to radioactive Ni (in the range of ∼1.5 × 10−10 mol L−1 to ∼1.5 × 10−9 mol L−1 of spiked 63Ni) were also tested using batch experiments. Sorption kinetics of 63Ni on the Callovian–Oxfordian clay-rich rock was explained by two mechanisms: fast and reversible

  7. Fluid-related modifications of Cr-spinel and olivine from ophiolitic peridotites by contact metamorphism of granitic intrusions in the Ablah area, Saudi Arabia

    Science.gov (United States)

    Ahmed, Ahmed Hassan; Surour, Adel Abdullah

    2016-05-01

    The Ablah serpentinized peridotites and overlying layered metagabbros represent an allochthonous piece of a dismembered ophiolite in the southern Hijaz terrane that belongs to the Neoproterozoic Arabian Shield in Saudi Arabia. On both sides, the ophiolite is bounded by wider domains of granitic intrusions and volcano-sedimentary successions, all together follow a N-S trend. The protolith of the Ablah serpentinized peridotites is mainly harzburgite which is partly or totally serpentinized. Carbonate veins of variable sizes invade and hydrate the serpentinized peridotites. Away from the contact with the granitic intrusions, fresh primary (igneous) olivine and Cr-spinel are preserved in the partly serpentinized peridotites. These relict primary minerals are used to infer their tectonic setting of formation as a nascent spreading center rock association of mid-ocean ridge or back-arc basin setting. Based on the re-distribution of elements related to different thermal effects, three patterns of Cr-spinel modification can be defined. The first pattern can be followed in the partly serpentinized peridotites where Cr-spinel displays simple zoning that is characterized by sharp contact between primary Al-rich cores and secondary Fe3+-rich rims. These cores and rims are homogeneous and show progressive decrease in Mg, Al and Cr, but with remarkable increase in Fe3+ and Fe2+ toward the rims. Mineral assemblage in equilibrium with this type of Cr-spinel is primary olivine + antigorite + chlorite ± talc ± chrysotile. The second pattern of Cr-spinel modification is represented by homogeneous weakly zoned Cr-rich spinel with no distinct sharp contacts between Cr-rich cores and magnetite rims. Cr-spinel cores of this type are rich in Cr and Fe2+, and poor in Mg, Al and Fe3+. The mineral assemblage in equilibrium with this Cr-spinel type is Fe-rich olivine + antigorite + enstatite + chlorite + tremolite + anthophyllite ± talc. The third pattern is defined by pervasive

  8. The Marianas-San Marcos vein system: characteristics of a shallow low sulfidation epithermal Au-Ag deposit in the Cerro Negro district, Deseado Massif, Patagonia, Argentina

    Science.gov (United States)

    Vidal, Conrado Permuy; Guido, Diego M.; Jovic, Sebastián M.; Bodnar, Robert J.; Moncada, Daniel; Melgarejo, Joan Carles; Hames, Willis

    2016-08-01

    The Cerro Negro district, within the Argentinian Deseado Massif province, has become one of the most significant recent epithermal discoveries, with estimated reserves plus resources of ˜6.7 Moz Au equivalent. The Marianas-San Marcos vein system contains about 70 % of the Au-Ag resources in the district. Mineralization consists of Upper Jurassic (155 Ma) epithermal Au- and Ag-rich veins of low to intermediate sulfidation style, hosted in and genetically related to Jurassic intermediate composition volcanic rocks (159-156 Ma). Veins have a complex infill history, represented by ten stages with clear crosscutting relationships that can be summarized in four main episodes: a low volume, metal-rich initial episode (E1), an extended banded quartz episode with minor mineralization (E2), a barren waning stage episode (E3), and a silver-rich late tectonic-hydrothermal episode (E4). The first three episodes are interpreted to have formed at the same time and probably from fluids of similar composition: a 290-230 °C fluid dominated by meteoric and volcanic waters (-3‰ to -0‰ δ18Owater), with <3 % NaCl equivalent salinity and with a magmatic source of sulfur (-1 to -2 ‰ δ34Swater). Metal was mainly precipitated at the beginning of vein formation (episode 1) due to a combination of boiling at ˜600 to 800 m below the paleowater table, and associated mixing/cooling processes, as evidenced by sulfide-rich bands showing crustiform-colloform quartz, adularia, and chlorite-smectite banding. During episodes 2 and 3, metal contents progressively decrease during continuing boiling conditions, and veins were filled by quartz and calcite during waning stages of the hydrothermal system, and the influx of bicarbonate waters (-6 to -8.5 ‰ δ18Owater). Hydrothermal alteration is characterized by proximal illite, adularia, and silica zone with chlorite and minor epidote, intermediate interlayered illite-smectite and a distal chlorite halo. This assemblage is in agreement with

  9. 鄂尔多斯盆地陇东地区长4+5油层组致密砂岩储层成岩作用及成岩相%Diagenesis and diagenetic facies of the Chang 4+5 tight sandstone reservoirs in Longdong area,Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    王峰; 陈蓉; 田景春; 李明瑞; 章辉若; 刘鑫

    2014-01-01

    Based on thin sections,SEM,X-ray diffraction,mercury injection,this paper analyzed the diagenesis and its im-pact on Chang4+5(the 4th and 5th Member of the Yanchang Fm)oil layers in Longdong area,Ordos Basin.Based on the analysis results ,we studied the characteristics of diagenetic facies and the distribution of favorable facies .The Chang4+5 oil layers is at the mid-diagenetic A-B stage ,and the early compaction and carbonate cementation resulted in loss of great numbers of primary pores ,resulting in poor reservoir quality .However,the early chlorite thin film was favorable for the protection of primary pores and dissolution improved reservoir quality .According to the impact of the diagenesis on reser-voir quality,five types of diagenetic facies were identified ,namely chlorite thin film-residual intergranular pore facies , kaolinite cementation-feldspar dissolution facies , illite cementation-feldspar dissolution facies , carbonate cementation facies and siliceous-illite cementation facies .High quality reservoirs are closely related to the diagenetic facies , and the chlorite thin film-residual intergranular pore diagenetic facies is the best in reservoir physical property and petroliferous property ,thus is the most favorable diagenetic facies for oil enrichment in this area .%运用铸体薄片鉴定、扫描电镜、X-衍射及高压压汞等测试方法,系统分析了鄂尔多斯盆地陇东地区长4+5油层组砂岩储层的成岩作用特征及其对储层物性的影响,进而对储层成岩相特征及有利成岩相的分布进行了研究。结果表明:研究区长4+5储层成岩阶段总体处于中成岩阶段A-B期,压实作用与碳酸盐胶结作用造成原始孔隙的大量损失,使储集层物性变差;早期绿泥石薄膜的发育有利于原生孔隙的保存;溶蚀作用使物性得到明显改善。根据成岩作用对物性的影响,划分出绿泥石薄膜-粒间孔相、高岭石胶结-长石溶蚀相、伊

  10. The Marianas-San Marcos vein system: characteristics of a shallow low sulfidation epithermal Au-Ag deposit in the Cerro Negro district, Deseado Massif, Patagonia, Argentina

    Science.gov (United States)

    Vidal, Conrado Permuy; Guido, Diego M.; Jovic, Sebastián M.; Bodnar, Robert J.; Moncada, Daniel; Melgarejo, Joan Carles; Hames, Willis

    2016-01-01

    The Cerro Negro district, within the Argentinian Deseado Massif province, has become one of the most significant recent epithermal discoveries, with estimated reserves plus resources of ˜6.7 Moz Au equivalent. The Marianas-San Marcos vein system contains about 70 % of the Au-Ag resources in the district. Mineralization consists of Upper Jurassic (155 Ma) epithermal Au- and Ag-rich veins of low to intermediate sulfidation style, hosted in and genetically related to Jurassic intermediate composition volcanic rocks (159-156 Ma). Veins have a complex infill history, represented by ten stages with clear crosscutting relationships that can be summarized in four main episodes: a low volume, metal-rich initial episode (E1), an extended banded quartz episode with minor mineralization (E2), a barren waning stage episode (E3), and a silver-rich late tectonic-hydrothermal episode (E4). The first three episodes are interpreted to have formed at the same time and probably from fluids of similar composition: a 290-230 °C fluid dominated by meteoric and volcanic waters (-3‰ to -0‰ δ18Owater), with <3 % NaCl equivalent salinity and with a magmatic source of sulfur (-1 to -2 ‰ δ34Swater). Metal was mainly precipitated at the beginning of vein formation (episode 1) due to a combination of boiling at ˜600 to 800 m below the paleowater table, and associated mixing/cooling processes, as evidenced by sulfide-rich bands showing crustiform-colloform quartz, adularia, and chlorite-smectite banding. During episodes 2 and 3, metal contents progressively decrease during continuing boiling conditions, and veins were filled by quartz and calcite during waning stages of the hydrothermal system, and the influx of bicarbonate waters (-6 to -8.5 ‰ δ18Owater). Hydrothermal alteration is characterized by proximal illite, adularia, and silica zone with chlorite and minor epidote, intermediate interlayered illite-smectite and a distal chlorite halo. This assemblage is in agreement with

  11. Mineralogical investigations of the interaction between iron corrosion products and bentonite from the NF-PRO Experiments (Phase 1)

    International Nuclear Information System (INIS)

    observations, potentially indicating the early stages of conversion of montmorillonite towards an iron-rich clay mineral as a result of interaction with Fe released by the corrosion of iron or steel. The cation exchange capacity (CEC) and exchangeable cation chemistry of the bentonite was also seen to be subtly affected by interaction with Fe. Bentonite from within the zones where corroded steel wires were present displayed a slightly reduced CEC, and depletion in exchangeable Ca and Na, and an increase in exchangeable Fe. This is consistent with at least partial displacement of the interlayer cations in montmorillonite by Fe. The loss in CEC might also correlate with a partial conversion of the montmorillonite to chlorite, which is tentatively suggested from the XRD analyses. Fe released from the corroding steel was also observed to displace Ca2+ from the interlayer cation sites in the montmorillonite component. This was manifested by the marked concentration of Ca at the interface with the corroding metal and along the leading edges of 'fronts' of Fe diffusing into the bentonite matrix. The displaced Ca was seen to have re-precipitated as aragonite. The petrographical observations show that the bentonite within the alteration zone, that has reacted with and is enriched by Fe, has a tendency to show significantly reduced shrinkage on sample drying in comparison to the background unaltered bentonite. Conversely, this would suggest that the reacted and altered clay will also have less ability to swell on hydration with water. This behaviour might be consistent with the partial conversion of the montmorillonite to an iron rich dioctahedral smectite such as nontronite, or to non-swelling clay mineral such as chlorite (or chlorite-smectite mixed-layer clay). If this is the case, then this may have important implications for the long-term behaviour of bentonite seals around radioactive waste canisters made of iron or steel

  12. Mineralogy and microstructure of roofing slate: thermo-optical behaviour and fissility

    Directory of Open Access Journals (Sweden)

    García-Guinea, J.

    1998-09-01

    Full Text Available The mineralogy and microstructure, which affect the slaty cleavage, are linked with the strong preferred orientation of phyllosilicates and this enables the rock to be split into large, thin, flat sheets. Roofing slate samples with different commercial fissilities have been analyzed by radioluminescence (RL, thermoluminescence (3DTL, by X-ray diffraction (XRD, by scanning electron microscopy (SEM using the back-scattered mode (BSEI and by electron microprobe (EMP. They are made up of white micas, chlorite, quartz, detrital feldspars, ilmenite, pyrite, rutile apatite and tourmaline. Texturally, all consist of silt-sized clasts of detrital quartz, feldspars, chlorite-mica stacks, muscovite and ilmenite in a recrystalline, lepidoblastic matrix of white micas and chlorite with quartz lenses, all showing a very strong preferred orientation. The luminescence emission centers are a low broad blue band around the 400 nm spectra positions linked with alkali losses and formation of [AlO4]º defects; a peak at 473 nm interpreted as a the first thermal step (150-300ºC of a non-isothermal dehydroxylation of the slate phyllosilicates; and a 568 nm peak which agrees with Mn2+ point defects in aluminosilicate lattices. The studies on the slaty cleavage could be significant because Spain is the largest producer of roofing slate tiles in the world (87% of world production.

    La exfoliación de las pizarras depende fundamentalmente de su mineralogía y microestructura, especialmente de la fuerte orientación de los filosilicatos. Esta propiedad permite hendir o abrir las pizarras de techar en láminas muy grandes, delgadas y planas. Se han analizado varias pizarras de techar con diferentes calidades comerciales, correspondientes a diferentes grados de físibilidad, por radioluminiscencia (RL, termoluminiscencia espectral (TL3D, difracción de rayos X (DRX, microscopía electrónica de barrido (MEB utilizando el modo backscattered (BSEI

  13. Mineralogy, chemistry of magnetite and genesis of Korkora-1 iron deposit, east of Takab, NW Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Maanijou

    2014-10-01

    Full Text Available Introduction There is an iron mining complex called Shahrak 60 km east of Takab town, NW Iran. The exploration in the Shahrak deposit (general name for all iron deposits of the area started in 1992 by Foolad Saba Noor Co. and continued in several periods until 2008. The Shahrak deposit comprising 10 ore deposits including Korkora-1, Korkora-2, Shahrak-1, Shahrak-2, Shahrak-3, Cheshmeh, Golezar, Sarab-1, Sarab-2, and Sarab-3 deposits Sheikhi, 1995 with total 60 million tons of proved ore reserves. The Fe grade ranges from 45 to 65% (average 50%. The ore reserves of these deposits vary and the largest one is Korkora-1 with 15 million tons of 55% Fe and 0.64% S. The Korkora-1 ore deposit is located in western Azarbaijan and Urumieh-Dokhtar volcanic zone, at the latitude of 36°21.8´, and longitude of 47°32´. Materials and methods Six thin-polished sections were made on magnetite, garnet, and amphibole for EPMA (Electron Probe Micro Analysis. EPMA was performed using a JEOL JXA-733 electron microprobe at the University of New Brunswick, Canada, with wavelength-dispersive spectrometers. Results and discussion Outcropped units of the area are calc-alkaline volcanics of rhyolite, andesite and dacite and carbonate rocks of Qom Formation in which intrusion of diorite to granodiorite and quartzdoirite caused contact metamorphism, alteration plus skarnization and formation of actinolite, talc, chlorite, phlogopite, quartz, calcite, epidote and marblization in the vicinity of the ore deposit. Iron mineralization formed at the contacts of andesite and dacite with carbonates in Oligo-Miocene. The study area consists of skarn, metamorphic rocks, and iron ore zones. The shape of the deposit is lentoid to horizontal with some alteration halos. The ore occurred as replacement, massive, disseminated, open-space filling and breccia. The ore minerals of the deposit include low Ti-magnetite (0.04 to 0.2 wt % Ti, minor apatite, and sulfide minerals such as pyrite

  14. Site investigation SFR. Fracture mineralogy including identification of uranium phases and hydrochemical characterisation of groundwater in borehole KFR106

    International Nuclear Information System (INIS)

    This report presents the fracture mineralogy and hydrochemistry of borehole KFR106. The most abundant fracture minerals in the examined drill core samples are clay minerals, calcite, quartz and adularia; chlorite is also common but is mostly altered and found interlayered with corrensite. The most common clay mineral is a mixed layer clay consisting of illite-smectite. Pyrite, galena, chalcopyrite, barite (-celestine) and hematite are also commonly found in the fractures, but usually in trace amounts. Other minerals identified in the examined fractures are U-phosphate, pitchblende, U(Ca)-silicate, asphaltite, biotite, monazite, fluorite, titanite, sericite, xenotime, rutile and (Ca, REEs)-carbonate. Uranium has been introduced, mobilised and reprecipitated during at least four different episodes: 1) Originally, during emplacement of U-rich pegmatites, probably as uraninite. 2) At a second event, uranium was mobilised under brittle conditions during formation of breccia/cataclasite. Uraninite was altered to pitchblende and partly coffinitised. Mobilised uranium precipitated as pitchblende closely associated with hematite and chlorite in cataclasite and fracture sealings prior to 1,000 Ma. 3) During the Palaeozoic U was remobilised and precipitated as U-phosphate on open fracture surfaces. 4) An amorphous U-silicate has also been found in open fractures; the age of this precipitation is not known but it is inferred to be Palaeozoic or younger. Groundwater was sampled in two sections in borehole KFR106 with pumping sequences of about 6 days for each section. The samples from sections KFR106:1 and KFR106:2 (260-300 m and 143-259 m borehole length, i.e. -261 and -187 m.a.s.l. mid elevation of the section, respectively) were taken in November 2009 and yielded groundwater chemistry data in accordance with SKB chemistry class 3 and 5. In section KFR106:1 and KFR106:2, the chloride contents were 850 and 1,150 mg/L and the drilling water content 6 and 4%, respectively

  15. Alteration hydrothermale et deformation ductile des roches volcaniques acides associees au gisement sulfure de draa sfar (Jebilet Centrales, Maroc

    Directory of Open Access Journals (Sweden)

    Zinbi, Y.

    2005-12-01

    Full Text Available The volcanics and volcanoclastic rocks of Draa Sfar (Central Jebilet, Moroccan hercynian belt are affected by ductile stress and hydrothermal alteration accompanied by a weak degree of metamorphism (greenschist facies. Some N-S oriented shearing zones, affect locally these formations while being the site of an important hydrothermal activity. The consequences of these transformations from a non to slightly- deformed rhyodacite, show that through these ductile shearing zones: (1 the mineralogical assemblage of hydrothermal alteration is essentially formed by chlorite, sericite, quartz and magnetite; (2 the gradual increase of the alteration indexes is accompanied by the destruction of the phenocrists and the recrystallization of the matrix by phyllosilicates and quartz; (3 the progressive transfer of material is more intense in the more deformed zones where the values of Ti, Al and Zr remain constant. These shearing zones played a very important role in the circulation of fluids and the transformation of the rhyodacite of Draa Sfar.Les roches volcaniques et volcanoclastiques de Draa Sfar (Jebilet centrales, Maroc hercynien sont affectées par une déformation ductile accompagnée d’un métamorphisme de faible degré (faciès schistes verts et d’une altération hydrothermale. Des zones de cisaillement de direction N-S, ont affecté localement ces formations tout en étant vecteurs d’une importante activité hydrothermale. Le suivi de ces transformations à partir de la rhyodacite non ou peu déformée, montre qu’à travers ces zones de cisaillements ductiles : (1 l’assemblage minéralogique d’altération hydrothermale est formé essentiellement de chlorite, de séricite, de quartz et de magnétite ; (2 l’augmentation graduelle des indices d’altération s’exprime par la destruction des phénocristaux au profit d’une matrice recristallisée en phyllosilicates et quartz ; (3 le transfert progressif de la matière est plus intense

  16. An experimental evaluation of the reaction of granite with streamwater, seawater and NaCl solutions at 200°C

    Science.gov (United States)

    Savage, David; Bateman, Keith; Milodowski, Antoni E.; Hughes, Colin R.

    1993-10-01

    Experiments reacting granite with streamwater, seawater, and NaCl solutions have been conducted at 200°C, 50 MPa under batch conditions using direct-sampling autoclaves for durations up to 80 days. Granite-streamwater experiments at 10:1 and 2:1 water/rock ratios produced fluids of low TDS (precipitated was directly related to the amount of Mg present in the initial system. The reaction of granite with seawater produced a fluid of low pH (≈ 3.5), and principal changes in the fluid chemistry as follows: a gain of SiO 2; and losses of sulphate, magnesium, and calcium. Appreciable mobilisation of heavy metals into the fluid phase such as Fe (up to 15 mg/l) and Mn (up to 2 mg/l) were noted. Solid precipitates consisted of anhydrite, caminite (magnesium hydroxide sulphate hydrate) and a mixed-layer smectite-chlorite clay. The low pH of the evolved fluid is attributed to the precipitation of the hydroxyl-consuming mineral phases, caminite and the smectite-chlorite clay. The reaction of granite with NaCl solutions (0.008 and 0.028 M) produced fluids which were similar to those of the streamwater experiments. However, pH was lower in the NaCl experiments (=7.4-7.8), so that the steady-state concentrations of a number of the cationic constituents of the fluids were slightly greater in these experiments compared with the streamwater experiments. The dominant constituent of the product fluids (excepting NaCl) was SiO 2, the concentration of which was buffered by quartz solubility. The sole secondary solid product identified was a sparsely-developed illitic clay. The injection of a Li-Rb-Cs-Na-Cl fluid into the experiments after 1000 hours demonstrated that the concentrations of the rare alkalis in the fluids were controlled by non-equilibrium processes. Other chemical components perturbed by dilution returned to the steady states developed prior to the injection process, demonstrating buffering by metastable reactions with the rock. The steady-state composition of the

  17. Site investigation SFR. Fracture mineralogy including identification of uranium phases and hydrochemical characterisation of groundwater in borehole KFR106

    Energy Technology Data Exchange (ETDEWEB)

    Sandstroem, Bjoern [WSP Sverige AB, Goeteborg (Sweden); Nilsson, Kersti [Geosigma AB, Uppsala (Sweden); Tullborg, Eva-Lena [Terralogica AB, Graabo (Sweden)

    2011-12-15

    This report presents the fracture mineralogy and hydrochemistry of borehole KFR106. The most abundant fracture minerals in the examined drill core samples are clay minerals, calcite, quartz and adularia; chlorite is also common but is mostly altered and found interlayered with corrensite. The most common clay mineral is a mixed layer clay consisting of illite-smectite. Pyrite, galena, chalcopyrite, barite (-celestine) and hematite are also commonly found in the fractures, but usually in trace amounts. Other minerals identified in the examined fractures are U-phosphate, pitchblende, U(Ca)-silicate, asphaltite, biotite, monazite, fluorite, titanite, sericite, xenotime, rutile and (Ca, REEs)-carbonate. Uranium has been introduced, mobilised and reprecipitated during at least four different episodes: 1) Originally, during emplacement of U-rich pegmatites, probably as uraninite. 2) At a second event, uranium was mobilised under brittle conditions during formation of breccia/cataclasite. Uraninite was altered to pitchblende and partly coffinitised. Mobilised uranium precipitated as pitchblende closely associated with hematite and chlorite in cataclasite and fracture sealings prior to 1,000 Ma. 3) During the Palaeozoic U was remobilised and precipitated as U-phosphate on open fracture surfaces. 4) An amorphous U-silicate has also been found in open fractures; the age of this precipitation is not known but it is inferred to be Palaeozoic or younger. Groundwater was sampled in two sections in borehole KFR106 with pumping sequences of about 6 days for each section. The samples from sections KFR106:1 and KFR106:2 (260-300 m and 143-259 m borehole length, i.e. -261 and -187 m.a.s.l. mid elevation of the section, respectively) were taken in November 2009 and yielded groundwater chemistry data in accordance with SKB chemistry class 3 and 5. In section KFR106:1 and KFR106:2, the chloride contents were 850 and 1,150 mg/L and the drilling water content 6 and 4%, respectively

  18. Petrology and radiogeology of the Stripa pluton

    Energy Technology Data Exchange (ETDEWEB)

    Wollenberg, Harold; Flexser, Steve; Andersson, Lennart

    1980-12-01

    To better define the character of the rock encompassing the thermomechanical and hydrological experiments at the Stripa mine in central Sweden, and to help determine the size of the Stripa pluton, detailed studies were conducted of the petrology and radiogeology of the quartz monzonite and adjacent rocks. Petrologic studies emphasized optical petrography, with supplementary X-ray diffraction, X-ray fluorescence and microprobe analyses. Radiogeologic investigations were based primarily on surface and underground gamma-ray spectrometric measurements of uranium, thorium and potassium, supplemented by laboratory gamma spectrometric analyses and fission-track radiographic determinations of the locations and abundance of uranium in the rock matrix. Both the quartz monzonite and the metavolcanic leptite which it intruded are strongly fractured. Two stages of fracture filling are evident; an earlier stage encompassing quartz, sericite, feldspar, epidote, and chlorite, and a later stage dominated by carbonate minerals. The Stripa quartz monzonite is chemically and mineralogically distinct from other plutons in the region. Muscovite is the predominant mica in the quartz monzonite; biotite has been altered to chlorite, hornblende is absent, and accessory minerals are scarce. In contrast, in other plutons in the Stripa region biotite and hornblende are prominent mafic minerals and accessory minerals are abundant. The Stripa quartz monzonite is also considerably more radioactive than the leptite and other plutons in the region. Uranium and thorium abundances are both- 30 ppm, considerably higher than in "normal" granitic rocks where the thorium-to-uranium ratio generally exceeds 2. Potassium-argon dating of muscovite from the Stripa quartz monzonite indicates that this rock may be older, at 1691 million years than granitic rock of the neighboring Gusselby and Kloten massifs, whose ages, based on K-Ar dating of biotite, are respectively 1604 and 1640 m.y. Heat flow and heat

  19. Chloroxyanion Residue Quantification in Cantaloupes Treated with Chlorine Dioxide Gas.

    Science.gov (United States)

    Kaur, Simran; Smith, David J; Morgan, Mark T

    2015-09-01

    Previous studies show that treatment of cantaloupes with chlorine dioxide (ClO2) gas at 5 mg/liter for 10 min results in a significant reduction (P < 0.05) in initial microflora, an increase in shelf life without any alteration in color, and a 4.6- and 4.3-log reduction of Escherichia coli O157:H7 and Listeria monocytogenes, respectively. However, this treatment could result in the presence of chloroxyanion residues, such as chloride (Cl(-)), chlorite (ClO2(-)), chlorate (ClO3(-)), and perchlorate (ClO4(-)), which, apart from chloride, are a toxicity concern. Radiolabeled chlorine dioxide ((36)ClO2) gas was used to describe the identity and distribution of chloroxyanion residues in or on cantaloupe subsequent to fumigation with ClO2 gas at a mean concentration of 5.1 ± 0.7 mg/liter for 10 min. Each treated cantaloupe was separated into rind, flesh, and mixed (rind and flesh) sections, which were blended and centrifuged to give the corresponding sera fractions. Radioactivity detected, ratio of radioactivity to mass of chlorite in initial ClO2 gas generation reaction, and distribution of chloroxyanions in serum samples were used to calculate residue concentrations in flesh, rind, and mixed samples. Anions detected on the cantaloupe were Cl(-) (∼ 90%) and ClO3(-) (∼ 10%), located primarily in the rind (19.3 ± 8.0 μg of Cl(-)/g of rind and 4.8 ± 2.3 μg of ClO3(-)/g of rind, n = 6). Cantaloupe flesh (∼ 200 g) directly exposed to(36)ClO2 gas treatment showed the presence of only Cl(-) residues (8.1 ± 1.0 μg of Cl(-)/g of flesh, n = 3). Results indicate chloroxyanion residues Cl(-) and ClO3(-) are only present on the rind of whole cantaloupes treated with ClO2 gas. However during cutting, residues may be transferred to the fruit flesh. Because Cl(-) is not toxic, only ClO3(-) would be a toxicity concern, but the levels transferred from rind to flesh are very low. In the case of fruit flesh directly exposed to ClO2 gas, only nontoxic Cl(-) was detected. This

  20. Desilicification and iron activation-reprecipitation in the high-grade magnetite ores in BIFs of the Anshan-Benxi area, China: Evidence from geology, geochemistry and stable isotopic characteristics

    Science.gov (United States)

    Li, Hou-Min; Yang, Xiu-Qing; Li, Li-Xing; Zhang, Zhao-Chong; Liu, Ming-Jun; Yao, Tong; Chen, Jing

    2015-12-01

    The high-grade magnetite ores related to banded iron formations (BIFs) in the Anshan-Benxi area, Liaoning Province in China, have been widely interpreted as the product of replacement of protore by epigenetic hydrothermal fluids. The high-grade iron ore reserves in the mining area II (164 million tons) in the Gongchangling (G2) and Qidashan-Wangjiabuzi (QW) iron deposits (11.45 million tons) are the largest deposits in the Anshan-Benxi area. We present a detailed comparison of the geology, geochemical and stable isotopic compositions of the iron ores in the G2 with those in the QW to constrain the role of desilicification and iron activation-reprecipitation in converting the BIFs to high-grade magnetite ores. These two deposits show marked difference in wall-rock alteration, geochemical features, and oxygen and sulfur isotopic compositions. Wall-rock alteration in the G2 is characterized by garnetization, actinolitization, and chloritization, whereas the QW shows chloritization, biotitization and sericitization. The geochemistry of altered rocks in the G2 is characterized by slight REE fractionation, positive Eu and no significant Ce anomalies, whereas the QW is characterized by high ΣREE contents, strong REE fractionation, and the absence of significant Eu and Ce anomalies. High-grade iron ores in the G2 show similar δ18OV-SMOW values for magnetite, lower δ18OV-SMOW values for quartz and higher δ34SV-CDT values for pyrite when compared to the BIFs, whereas the QW shows lower δ18OV-SMOW values for magnetite, similar δ18OV-SMOW values for quartz and similar δ34SV-CDT values for pyrite. These features indicate that desilicification process by hypogene alkaline-rich hydrothermal fluids were possibly responsible for the formation of high-grade iron ores in the G2 whereas iron activation-reprecipitation process by migmatitic-hydrothermal fluids generated the high-grade iron orebodies in QW.

  1. Hydrofracturing of Sediment and Hydrated MORB's during Subduction of Ocean Crust

    Science.gov (United States)

    Nabelek, P. I.

    2015-12-01

    Dehydration accompanying metamorphism of sediment and hydrated mafic ocean crust during ocean plate subduction can potentially lead to fracturing and intraplate tremors. As rocks are buried, they lose porosity and permeability and eventually pass into the lithostatic pressure regime where the porosity and permeability are thought to be very small. Pore fluid pressure generation stemming from metamorphic reactions was modeled using the program SUTRAMET (Nabelek et al., 2014), which is a modified version of the program SUTRA (Voss & Provost, 2002). The program allows modeling of metamorphic reactions at high pressures and temperatures and incorporates transient porosity and permeability changes due to overpressure and changing volumes of metamorphic assemblages. Permeabilities (k) of 10-18 and 10-20 m2 within the brittle regime were modeled. The model assumes continuous subduction with fluids generated at horizons where specific P-T conditions for reactions exist. Temperature gradient was assumed to be 10°C/km and the vertical component of subduction velocity to be at 0.85 cm/y. The model reactions in sediment (Campito Formation of western California as a proxy) and average MORB were generated by the program Theriak-Domino (de Capitani and Petrakakis, 2010). The initial sediment mineralogy includes albite, K-feldspar, phengite, chlorite, and lawsonite. The final mineralogy for the 10°C/km gradient is quartz, phengite, garnet, and pyroxene with jadeite and acmite components. The initial mineralogy of MORB includes chlorite, amphibole, pumpelyite, albite and quartz and the final eclogite mineralogy includes garnet, cpx, kyanite and quartz. Calculations show that at k = 10-18 m2, pore fluid pressure can reach 450 MPa. Pore pressure is reduced by negative ∆V of mineral assemblages stemming from reactions; nevertheless, for the garnet-forming reaction, pore pressure is about 110 MPa. Assuming a tensile strength of 15 MPa and fracture aperture given by rock

  2. Petrology of HP/LT metapelitic rocks of an accretionary wedge, the Central Pontides, Turkey: evidence for tectonic stacking and syn-subduction exhumation

    Science.gov (United States)

    Aygül, Mesut; Okay, Aral; Oberhänsli, Roland

    2015-04-01

    Cretaceous HP/LT chloritoid-bearing metapelitic rocks crop out widely in the central part of the Pontides, northern Turkey. They are associated with eclogite to blueschist-facies metabasites and represent deep levels of an underplated subduction-accretion complex, which is tectonically overlain by low-grade HP phyllite/metasandstone intercalation along an extensional shear zone. Close to the shear zone, the footwall micaschists consist of quartz, phengite, paragonite, chlorite, rutile with syn-kinematic albite porphyroblast formed by pervasive shearing during exhumation. This type of micaschists is tourmaline-bearing and their retrograde nature suggests high-fluid flux along shear zones. Peak metamorphic assemblages are partly preserved in the chloritoid-micaschist farther away from the shear zone. Three peak metamorphic assemblages are identified and their PT conditions are constrained by pseudosections produced by Theriak-Domino and by Raman spectra of carbonaceous material: 1) garnet-chloritoid-glaucophane with lawsonite pseudomorphs (P: 17.5 ± 1 Kbar, T: 390-450 °C) 2) chloritoid with glaucophane pseudomorphs (P: 16-18 Kbar, T: 475 ± 40 °C) and 3) relatively high-Mg chloritoid (17%) with jadeite pseudomorphs (22-25 Kbar; T: 440 ± 30 °C) in addition to phengite, paragonite, quartz, chlorite, rutile. The last mineral assemblage is interpreted as transformation of the chloritoid + glaucophane assemblage to chloritoid + jadeite paragenesis with increasing pressure. Absence of tourmaline suggests that the chloritoid-micaschist did not interact with B-rich fluids during zero strain exhumation. Peak metamorphic assemblages and PT estimates suggest tectonic stacking within wedge with different depths of burial. 40Ar/39Ar phengite age of a pervasively sheared footwall micaschist is constrained to 100.6 ± 1.3 Ma and that of a chloritoid-micaschist is constrained to 91.8 ± 1.8 Ma suggesting exhumation during on-going subduction. Coupling and exhumation of the

  3. Prediction of Diagenetic Facies using Well Logs: Evidences from Upper Triassic Yanchang Formation Chang 8 Sandstones in Jiyuan Region, Ordos Basin, China

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    Lai Jin

    2016-05-01

    Full Text Available The eighth member of Upper Triassic Yanchang Formation (Chang 8 is the major oil reservoir unit in Jiyuan oil field, though with the high potential for oil exploration. The Chang 8 sandstones are characterized with low porosity, low permeability and strong microscopic heterogeneities due to the complex deep-burial diagenetic history. Detailed petrological studies by thin section, X-ray diffraction, scanning electron microscopy, core analysis have been used to investigate the lithogology characteristics, diagenesis, diagenetic minerals and their coupling impacts on reservoir property. The results show that Chang 8 sandstones comprise fine to mediumgrained subarkoses, feldspathic litharenites. The pore systems are dominated by remaining primary intergranular pores, secondary dissolution porosity and micropores. Then, five diagenetic facies were divided in Chang 8 sandstones based on the type and degree of diagenesis, diagenetic minerals assemblages and their coupling effects on the reservoir quality. They consist of grain-coating chlorite weak dissolution facies, unstable component dissolution facies, tight compaction facies, clay minerals filling facies and carbonate cementation facies. The well logging response characteristics of various diagenetic facies are summarized on Gamma Ray (GR, Density Logging (DEN, Acoustic (AC, Compensated Neutron Logging (CNL, and True Formation Resistivity (RT by translating diagenetic facies to well log responses, the diagenetic facies were defined by a set of log responses, and porosity, permeability ranges for each diagenetic facies were determined from core analyses. Well log data of Luo 13 and Chi 212 are processed to evaluate the accuracy of the predictive model. The diagenetic facies are predicted on the vertical profile based on the generated model. Predicted distribution of diagenetic facies precisely coincide with the microscopic observations, and diagenetic facies in Chang 8 sandstones are generally

  4. Diagenetic characteristics and reservoir quality of the Lower Cretaceous Biyadh sandstones at Kharir oilfield in the western central Masila Basin, Yemen

    Science.gov (United States)

    Hakimi, Mohammed Hail; Shalaby, Mohamed Ragab; Abdullah, Wan Hasiah

    2012-06-01

    The Lower Cretaceous Biyadh Formation in the Masila Basin is an important hydrocarbon reservoir. However, in spite of its importance as a reservoir, published studies on the Biyadh Formation more specifically on the diagenesis and relate with reservoir quality, are limited. Based on core samples from one well in the Kharir oilfield, western central Masila Basin, this study reports the lithologic and diagenetic characteristics of this reservoir. The Biyadh sandstones are very fine to very coarse-grained, moderate to well sorted quartzarenite and quartzwacke. The diagenetic processes recognized include mechanical compaction, cementation (carbonate, clay minerals, quartz overgrowths, and a minor amount of pyrite), and dissolution of the calcite cement and feldspar grains. The widespread occurrences of early calcite cement suggest that the Biyadh sandstones lost a significant amount of primary porosity at a very early stage of its diagenetic history. Based on the framework grain-cement relationships, precipitation of the early calcite cement was either accompanied or followed by the development of part of the pore-lining and pore-filling clay cements. Secondary porosity development occurred due to partial to complete dissolution of early calcite cement and feldspar grains. In addition to calcite, several different clay minerals including kaolinite and chlorite occur as pore-filling and pore-lining cements. Kaolinite largely occurs as vermiform and accelerated the minor porosity loss due to pore-occlusion. Chlorite coating grains helps to retain primary porosity a by retarding the envelopment of quartz overgrowths. Porosity and permeability data exhibit good inverse correlation with cement. Thus, reservoir quality is controlled by pore occluding cement. Diagenetic history of the Biyadh sandstones as established here is expected to help better understanding and exploitation of this reservoir. The relation between diagenesis and reservoir quality is as follows: the

  5. Constraining the thermal structure beneath Lusi: insights from temperature record in erupted clasts

    Science.gov (United States)

    Malvoisin, Benjamin; Mazzini, Adriano; Miller, Stephen

    2016-04-01

    Sedimentary units beneath Lusi from surface to depth are the Pucangan formation, the Upper Kalibeng formation where shales and then volcanoclastic clasts are found, the Kujung-Propuh-Tuban formation composed of carbonates and the Ngimbang formation composed of shales. Water and gas geochemistry as well as surface deformation indicate that Lusi is a hydrothermal system rooted at >4 km depth. However, the thermal structure beneath Lusi is still poorly constrained whereas it has first-order impacts on the physical and chemical processes observed during the eruption. In the framework of the Lusi Lab project (ERC grant n° 308126) and of a project of the Swiss National Science Foundation (n°160050) we studied erupted clasts collected at the crater site to determine their source and temperature record. Three types of clasts were studied based on morphological and mineralogical basis. The first type is limestones mainly composed of Ca- and Fe-bearing carbonates. The clasts of the second type are light grey shales (LGS) containing carbonaceous matter, illite/smectite mixture, plagioclase and quartz. The third type is also a shale with a black colour containing hydrocarbons (black shales, BS) and with the additional presence of Na-rich plagioclase, biotite and chlorite. The presence of these latter minerals indicates hydrothermal activity at relatively high temperature. Better constraints on temperature were obtained by using both Raman spectroscopic carbonaceous material thermometry (RSCM) and chlorite geothermometry. Temperatures below 200°C were determined for the LGS with RSCM. BS recorded two temperatures. The first one, around 170°C, is rather consistent with an extrapolation of the geothermal gradient measured before the eruption up to 4,000 m depth. Combined with mineralogical observations, this suggests that BS originate from the Ngimbang formation. The second recorded higher temperature around 250°C indicates heating, probably through interaction with high

  6. TEM analysis of the internal structures and mineralogy of Asian dust particles and the implications for optical modeling

    Directory of Open Access Journals (Sweden)

    G. Y. Jeong

    2014-03-01

    Full Text Available Mineral dust interacts with incoming/outgoing electromagnetic radiation in the atmosphere. This interaction depends on the microphysical properties of the dust particles, including size, mineral composition, external morphology, and internal structure. Ideally all these properties should be accounted for in dust remote sensing, the modeling of single-scattering properties, and radiative effect assessment. There have been many reports on the microphysical characterizations of mineral dust, but no investigations of the internal structures or mineral composition of individual dust particles. We explored the interiors of Asian dust particles using the combined application of focused ion beam thin-slice preparation and high-resolution transmission electron microscopy. The results showed that individual dust particles consisted of numerous mineral grains, which were organized into several types of internal structure: single and polycrystalline cores of quartz, feldspars, calcite, and amphibole often with oriented clay coatings; individual clay agglomerates of nano-thin clay platelets showing preferred to random orientations commonly with coarser mineral inclusions; and platy coarse phyllosilicates (muscovite, biotite, and chlorite. Micron to submicron pores were scattered throughout the interior of particles. Clays in the coatings and agglomerates were dominated by nano-thin platelets of the clay minerals of illite-smectite series including illite, smectite, and their mixed layers with subordinate kaolinite and clay-size chlorite. Submicron iron oxide grains, dominantly goethite, were distributed throughout the clay agglomerates and coatings. Unlike the common assumptions and simplifications, we found that the analyzed dust particles were irregularly shaped with birefringent, polycrystalline, and polymineralic heterogeneous compositions. Accounting for this structural and mineralogical makeup may improve the remote sensing retrieval of dust and the

  7. Diagenesis and reservoir quality evolution of palaeocene deep-water, marine sandstones, the Shetland-Faroes Basin, British continental shelf

    Energy Technology Data Exchange (ETDEWEB)

    Mansurbeg, H. [Department of Earth Sciences, Uppsala University, Villavaegen 16, SE 752 36 Uppsala (Sweden); Morad, S. [Department of Earth Sciences, Uppsala University, Villavaegen 16, SE 752 36 Uppsala (Sweden); Department of Petroleum Geosciences, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Salem, A. [Faculty of Education at Kafr El-Sheikh, Tanta University, Kafr El-Sheikh (Egypt); Marfil, R.; Caja, M.A. [Departmento Petrologia y Geoquimica, Facultad de Geologia, UCM, 28040 Madrid (Spain); El-ghali, M.A.K. (Geology Department, Al-Fateh University, P.O. Box 13696, Libya); Nystuen, J.P. [Department of Geosciences, University of Oslo, P.O. Box 1047 Blindern, NO-0316 Oslo (Norway); Amorosi, A. [Department of Earth Sciences, University of Bologna, Via Zamboni 67, 40127 Bologna (Italy); Garcia, D. [Centre SPIN, Department GENERIC, Ecole Nationale Superieure des Mines de Saint Etienne 158, Cours Fauriel 42023, Saint-Etienne (France); La Iglesia, A. [Instituto de Geologia Economica (CSIC-UCM), Facultad de Geologia, UCM, 28040 Madrid (Spain)

    2008-06-15

    The Palaeocene, deep-water marine sandstones recovered from six wells in the Shetland-Faroes Basin represent lowstand, transgressive and highstand systems tract turbiditic sediments. Mineralogic, petrographic, and geochemical analyses of these siliciclastics are used to decipher and discuss the diagenetic alterations and subsequent reservoir quality evolution. The Middle-Upper Palaeocene sandstones (subarkoses to arkoses) from the Shetland-Faroes Basin, British continental shelf are submarine turbiditic deposits that are cemented predominantly by carbonates, quartz and clay minerals. Carbonate cements (intergranular and grain replacive calcite, siderite, ferroan dolomite and ankerite) are of eogenetic and mesogenetic origins. The eogenetic alterations have been mediated by marine, meteoric and mixed marine/meteoric porewaters and resulted mainly in the precipitation of calcite ({delta}{sup 18}O{sub V-PDB}=-10.9 permille and -3.8 permille), trace amounts of non-ferroan dolomite, siderite ({delta}{sup 18}O{sub V-PDB}=-14.4 permille to -0.6 permille), as well as smectite and kaolinite in the lowstand systems tract (LST) and highstand systems tract (HST) turbiditic sandstone below the sequence boundary. Minor eogenetic siderite has precipitated between expanded and kaolinitized micas, primarily biotite. The mesogenetic alterations are interpreted to have been mediated by evolved marine porewaters and resulted in the precipitation of calcite ({delta}{sup 18}O{sub V-PDB}=-12.9 permille to -7.8 permille) and Fe-dolomite/ankerite ({delta}{sup 18}O{sub V-PDB}=-12.1 permille to -6.3 permille) at temperatures of 50-140 and 60-140 C, respectively. Quartz overgrowths and outgrowth, which post- and pre-date the mesogenetic carbonate cements is more common in the LST and TST of distal turbiditic sandstone. Discrete quartz cement, which is closely associated with illite and chlorite, is the final diagenetic phase. The clay minerals include intergranular and grain replacive

  8. In search of early life: Carbonate veins in Archean metamorphic rocks as potential hosts of biomarkers

    Science.gov (United States)

    Peters, Carl A.; Piazolo, Sandra; Webb, Gregory E.; Dutkiewicz, Adriana; George, Simon C.

    2016-11-01

    The detection of early life signatures using hydrocarbon biomarkers in Precambrian rocks struggles with contamination issues, unspecific biomarkers and the lack of suitable sedimentary rocks due to extensive thermal overprints. Importantly, host rocks must not have been exposed to temperatures above 250 °C as at these temperatures biomarkers are destroyed. Here we show that Archean sedimentary rocks from the Jeerinah Formation (2.63 billion yrs) and Carawine Dolomite (2.55 billion yrs) of the Pilbara Craton (Western Australia) drilled by the Agouron Institute in 2012, which previously were suggested to be suitable for biomarker studies, were metamorphosed to the greenschist facies. This is higher than previously reported. Both the mineral assemblages (carbonate, quartz, Fe-chlorite, muscovite, microcline, rutile, and pyrite with absence of illite) and chlorite geothermometry suggest that the rocks were exposed to temperatures higher than 300 °C and probably ∼400 °C, consistent with greenschist-facies metamorphism. This facies leads to the destruction of any biomarkers and explains why the extraction of hydrocarbon biomarkers from pristine drill cores has not been successful. However, we show that the rocks are cut by younger formation-specific carbonate veins containing primary oil-bearing fluid inclusions and solid bitumens. Type 1 veins in the Carawine Dolomite consist of dolomite, quartz and solid bitumen, whereas type 2 veins in the Jeerinah Formation consist of calcite. Within the veins fluid inclusion homogenisation temperatures and calcite twinning geothermometry indicate maximum temperatures of ∼200 °C for type 1 veins and ∼180 °C for type 2 veins. Type 1 veins have typical isotopic values for reprecipitated Archean sea-water carbonates, with δ13CVPDB ranging from - 3 ‰ to 0‰ and δ18OVPDB ranging from - 13 ‰ to - 7 ‰, while type 2 veins have isotopic values that are similar to hydrothermal carbonates, with δ13CVPDB ranging from - 18

  9. The Cedrolina Chromitite, Goiás State, Brazil: A Metamorphic Puzzle

    Directory of Open Access Journals (Sweden)

    Yuri de Melo Portella

    2016-09-01

    Full Text Available The Cedrolina chromitite body (Goiás-Brazil is concordantly emplaced within talc-chlorite schists that correspond to the poly-metamorphic product of ultramafic rocks inserted in the Pilar de Goiás Greenstone Belt (Central Brazil. The chromite ore displays a nodular structure consisting of rounded and ellipsoidal orbs (up to 1.5 cm in size, often strongly deformed and fractured, immersed in a matrix of silicates (mainly chlorite and talc. Chromite is characterized by high Cr# (0.80–0.86, high Fe2+# (0.70–0.94, and low TiO2 (av. = 0.18 wt % consistent with variation trends of spinels from metamorphic rocks. The chromitite contains a large suite of accessory phases, but only irarsite and laurite are believed to be relicts of the original igneous assemblage, whereas most accessory minerals are thought to be related to hydrothermal fluids that emanated from a nearby felsic intrusion, metamorphism and weathering. Rutile is one of the most abundant accessory minerals described, showing an unusually high Cr2O3 content (up to 39,200 ppm of Cr and commonly forming large anhedral grains (>100 µm that fill fractures (within chromite nodules and in the matrix or contain micro-inclusions of chromite. Using a trace element geothermometer, the rutile crystallization temperature is estimated at 550–600 °C (at 0.4–0.6 GPa, which is in agreement with P and T conditions proposed for the regional greenschist to low amphibolite facies metamorphic peak of the area. Textural, morphological, and compositional evidence confirm that rutile did not crystallize at high temperatures simultaneously with the host chromitite, but as a secondary metamorphic mineral. Rutile may have been formed as a metamorphic overgrowth product following deformation and regional metamorphic events, filling fractures and incorporating chromite fragments. High Cr contents in rutile very likely are due to Cr remobilization from Cr-spinel during metamorphism and suggest that Ti was

  10. Carbon, hydrogen, and oxygen isotope studies of the regional metamorphic complex at Naxos, Greece

    Science.gov (United States)

    Rye, R.O.; Schuiling, R.D.; Rye, D.M.; Jansen, J.B.H.

    1976-01-01

    At Naxos, Greece, a migmatite dome is surrounded by schists and marbles of decreasing metamorphic grade. Sillimanite, kyanite, biotite, chlorite, and glaucophane zones are recognized at successively greater distances from the migmatite dome. Quartz-muscovite and quartz-biotite oxygen isotope and mineralogie temperatures range from 350 to 700??C. The metamorphic complex can be divided into multiple schist-rich (including migmatites) and marblerich zones. The ??18O values of silicate minerals in migmatite and schist units and quartz segregations in the schist-rich zones decrease with increase in metamorphic grades. The calculated ??18OH2O values of the metamorphic fluids in the schist-rich zones decrease from about 15??? in the lower grades to an average of about 8.5??? in the migmatite. The ??D values of OH-minerals (muscovite, biotite, chlorite, and glaucophane) in the schist-rich zones also decrease with increase in grade. The calculated ??DH2O values for the metamorphic fluid decrease from -5??? in the glaucophane zone to an average of about -70??? in the migmatite. The ??D values of water in fluid inclusions in quartz segregations in the higher grade rocks are consistent with this trend. The??18O values of silicate minerals and quartz segregations in marble-rich zones are usually very large and were controlled by exchange with the adjacent marbles. The ??D values of the OH minerals in some marble-rich zones may reflect the value of water contained in the rocks prior to metamorphism. Detailed data on 20 marble units show systematic variations of ??18O values which depend upon metamorphic grade. Below the 540??C isograd very steep ??18O gradients at the margins and large ??18O values in the interior of the marbles indicate that oxygen isotope exchange with the adjacent schist units was usually limited to the margins of the marbles with more exchange occurring in the stratigraphic bottom than in the top margins. Above the 540??C isograd lower ??18O values occur in

  11. Mineralogy of the silica-epidote mineralized zone (SEMZ) in the Cerro Prieto geothermal reservoir, B.C., Mexico; Mineralogia de la zona mineralizada de silice-epidota (ZMSE) del yacimiento geotermico de Cerro Prieto, B.C., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Izquierdo, Georgina; Aragon, Alfonso; Portugal, Enrique; Arellano; Victor M [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Cuernavaca, Morelos (Mexico)]. E-mail: gim@iie.org.mx; Leon, Jesus de; Alvarez, Julio [Comision Federal de Electricidad, B.C. (Mexico)

    2006-07-15

    The distribution of hydrothermal minerals, mineral assemblages and fluid inclusion data were taken from drill cuttings from the production zone of wells all over the Cerro Prieto geothermal field. The production zone has been termed the silica-epidote mineralized zone (SEMZ), and is located in the deep part of the gray shale where thick layers of sandstone are found. Common mineral assemblages show three temperature ranges in the SEMZ: <200 degrees Celsius, 200-250 degrees Celsius and 250-300 degrees Celsius. The first range is characterized by clays, calcite and quartz; the second by quartz, epidote, chlorite and mica, and the third by epidote, amphibole, illite and chlorite. The study of fluid inclusions in authigenic grain quartz has shown two-phase fluid inclusions (liquid + vapor) of different salinities. A wide range exists of homogenization temperatures (Th) and for some wells there is a good agreement between Th and direct temperature measurements. [Spanish] Se determino la distribucion de minerales hidrotermales y las asociaciones parageneticas y se realizo el estudio microtermometrico de inclusiones fluidas a partir de recortes de perforacion de pozos de las distintas areas del campo geotermico de Cerro Prieto. Las muestras de recortes y nucleos de perforacion estudiados provienen de la zona de produccion a la que se le ha denominado Zona Mineralizada de Silice-Epidota (ZMSE), que se encuentra en la parte profunda de la lutita gris con importantes horizontes de areniscas. En esta zona las asociaciones parageneticas mas comunes han mostrado tres intervalos de temperatura para la ZMSE: <200 degrees Celsius, 200-250 degrees Celsius, 250-300 degrees Celsius. El primer intervalo esta caracterizado principalmente por arcillas, calcita y cuarzo; el segundo por cuarzo, epidota, clorita y micas, y el tercero por epidota, anfiboles, illita y clorita. El estudio de inclusiones fluidas en fragmentos de cuarzo autigenico mostro la presencia de inclusiones de dos fases

  12. Metamorphic evolution of the high-pressure metamorphic rocks from the Kemer area (Biga Peninsula, NW Turkey): Implications for the accretionary continental growth and closure of the Intra-Pontide Ocean

    Science.gov (United States)

    Aygül, M.; Topuz, G.; Satır, M.

    2009-04-01

    The northwestern part of the Biga Peninsula, NW Turkey, corresponds to the so-called Intra-Pontide suture, separating the Rhodope-Strandja zone to the north and Sakarya zone to the south. This suture zone is marked by the exposures of high-pressure metamorphics, oceanic accretionary complexes and ophiolites, which are widely covered by Eocene to Miocene volcanics and volcano-clastics, and crosscut by Eocene to Miocene granites. The Kemer area is one of the key-areas where high-pressure metamorphics and an ophiolitic mélange were widely exposed. This contribution deals with the metamorphic evolution of the Kemer high-pressure rocks, and their implications for the geodynamic evolution. The Kemer high-pressure rocks comprise predominantly micaschist, calcschist, marble and minor metabasite and serpentinite. The micaschists contain mineral assemblages involving garnet, phengite (3,30-3,44 c.p.f.u.), paragonite, epidote, chlorite, albite and titanite, and the metabasites consists of garnet, barrosite, albite, chlorite, epidote, albite and titanite. The equilibrium conditions are poorly constrained as 550 ± 50 °C temperature and >8-10 kbar pressure by Fe-Mg partitioning between garnet and phengite, and phengite-barometry, respectively. Timing of the high-pressure metamorphism is constrained as 84-64 Ma by Rb-Sr phengite-whole rock dating on four samples. Although the obtained age values display a wide scatter, they are consistent with geochronological data from the neighboring high-pressure areas: 86 ± 2 Ma from the Şarköy blueschists (Topuz et al. 2008) and 65-69 Ma from the Çamlıca garnet-micaschists (Okay and Satır, 2000). These data in conjunction with those from the literature suggest that Late Cretaceous represent a time of substantional accretionary continental growth related to the northward subduction of the Intra-Pontide Ocean. The closure of the Intra-Pontide Ocean is constrained between Late Cretaceous and Eocene, because Eocene volcanics and volcano

  13. Geology, alteration, and lithogeochemistry of the Hood volcanogenic massive sulfide (VMS) deposits, Nunavut, Canada

    Science.gov (United States)

    Mills, Hannah K.; Piercey, Stephen J.; Toole, Trish

    2016-04-01

    Finlayson Lake). The similarities of the ABVB to other Slave Craton greenstone belts further highlights the overall potential for greenstone-hosted VMS mineralization in the Slave Craton. Chlorite-sericite (+/- quartz) is the dominant hydrothermal alteration assemblage in the Hood deposits and is typical of VMS-style mineralization. Mass change calculations illustrate that elemental changes are typical of VMS environments with gains in Fe2O3, MgO, and base metals associated with chlorite alteration near mineralized zones; K2O gains associated with sericite alteration; and losses of Na2O in both alteration types.

  14. Mineralogy and Geochemistry of Clay Rich Volcano-Sedimentary Units from South of Elazıǧ Basin (Eastern Turkey)

    Science.gov (United States)

    Akkoca, Dicle Bal; Bakır, Zülfü

    2016-04-01

    The investigated area covers Upper Cretaeous Elazıǧ Magmatics and Middle Eocene Maden Group in the southern of Elazıǧ. X-ray powder diffraction (XRD), ICP-AES, ICP-MS were performed on three sections samples belonging to Elazıǧ Magmatics (Yemişlik and Kavallı sections) and Maden Group (Alıncık section), to investigate the depositional environment of volcano-sediments. The Elazıǧ magmatic rocks are composed of diorites, monzodiorites, quartz-diorites, and tonalites, basaltic pillow-lavas, andesitic lavas, and andesitic pyroclastic rocks. The Maden Group has a complex lithology consisting of limestones, red-green clayey limestones, sandstone, agglomerate, tuffs, reddish mudstone and basaltic-andesitic pillow lavas. Yemişlik section is composed mainly of altered grey tuffites, Kavallı section is represented by brown altered sediments, intercalated with basaltic, andesitic lava flows. Reddish mudstones constiture the Alıncık section. All samples consist of clay minerals (chlorite, illite), quartz, and feldspar. Yemişlik and Kavallı sections also contain calcite. Chlorite is the dominant clay in three sections. SiO2, Al2O3, Fe2O3, K2O contents show that Kavallı, Yemişlik and Alıncık samples are convenient with Fe shales and shales. The ratios of TiO2, Zr, Th/Sc, Zr/Sc, Y/Ni-Cr/V, Al/(Al+Fe+Mn) show dominance of neutral-basic volcanism in the area. REE concentrations of samples are normalized to chondrite values. It is determined that low light rare earth elements (LREEs) are enriched in comparison to high rare earth elements (HREEs), and the absence of Eu anomalies shows that our samples are generally mafic in composition. Rare earth elements (REE) of samples were compared with North American shale composite (NASC), European shale (ES) and Post-Archean Australian shale (PAAS). Elements are not in concurrence with these compositions. Th-Hf/3-Nb/16 tectono-magmatic discrimination diagram for samples in the study area indicate that all samples were

  15. Unbiased isotope equilibrium factors from partial isotope exchange experiments in 3-exchange site systems

    Science.gov (United States)

    Agrinier, Pierre; Javoy, Marc

    2016-09-01

    Two methods are available in order to evaluate the equilibrium isotope fractionation factors between exchange sites or phases from partial isotope exchange experiments. The first one developed by Northrop and Clayton (1966) is designed for isotope exchanges between two exchange sites (hereafter, the N&C method), the second one from Zheng et al. (1994) is a refinement of the first one to account for a third isotope exchanging site (hereafter, the Z method). In this paper, we use a simple model of isotope kinetic exchange for a 3-exchange site system (such as hydroxysilicates where oxygen occurs as OH and non-OH groups like in muscovite, chlorite, serpentine, or water or calcite) to explore the behavior of the N&C and Z methods. We show that these two methods lead to significant biases that cannot be detected with the usual graphical tests proposed by the authors. Our model shows that biases originate because isotopes are fractionated between all these exchanging sites. Actually, we point out that the variable mobility (or exchangeability) of isotopes in and between the exchange sites only controls the amplitude of the bias, but is not essential to the production of this bias as previously suggested. Setting a priori two of the three exchange sites at isotopic equilibrium remove the bias and thus is required for future partial exchange experiments to produce accurate and unbiased extrapolated equilibrium fractionation factors. Our modeling applied to published partial oxygen isotope exchange experiments for 3-exchange site systems (the muscovite-calcite (Chacko et al., 1996), the chlorite-water (Cole and Ripley, 1998) and the serpentine-water (Saccocia et al., 2009)) shows that the extrapolated equilibrium fractionation factors (reported as 1000 ln(α)) using either the N&C or the Z methods lead to bias that may reach several δ per mil in a few cases. These problematic cases, may be because experiments were conducted at low temperature and did not reach high

  16. Chloroxyanion Residue Quantification in Cantaloupes Treated with Chlorine Dioxide Gas.

    Science.gov (United States)

    Kaur, Simran; Smith, David J; Morgan, Mark T

    2015-09-01

    Previous studies show that treatment of cantaloupes with chlorine dioxide (ClO2) gas at 5 mg/liter for 10 min results in a significant reduction (P color, and a 4.6- and 4.3-log reduction of Escherichia coli O157:H7 and Listeria monocytogenes, respectively. However, this treatment could result in the presence of chloroxyanion residues, such as chloride (Cl(-)), chlorite (ClO2(-)), chlorate (ClO3(-)), and perchlorate (ClO4(-)), which, apart from chloride, are a toxicity concern. Radiolabeled chlorine dioxide ((36)ClO2) gas was used to describe the identity and distribution of chloroxyanion residues in or on cantaloupe subsequent to fumigation with ClO2 gas at a mean concentration of 5.1 ± 0.7 mg/liter for 10 min. Each treated cantaloupe was separated into rind, flesh, and mixed (rind and flesh) sections, which were blended and centrifuged to give the corresponding sera fractions. Radioactivity detected, ratio of radioactivity to mass of chlorite in initial ClO2 gas generation reaction, and distribution of chloroxyanions in serum samples were used to calculate residue concentrations in flesh, rind, and mixed samples. Anions detected on the cantaloupe were Cl(-) (∼ 90%) and ClO3(-) (∼ 10%), located primarily in the rind (19.3 ± 8.0 μg of Cl(-)/g of rind and 4.8 ± 2.3 μg of ClO3(-)/g of rind, n = 6). Cantaloupe flesh (∼ 200 g) directly exposed to(36)ClO2 gas treatment showed the presence of only Cl(-) residues (8.1 ± 1.0 μg of Cl(-)/g of flesh, n = 3). Results indicate chloroxyanion residues Cl(-) and ClO3(-) are only present on the rind of whole cantaloupes treated with ClO2 gas. However during cutting, residues may be transferred to the fruit flesh. Because Cl(-) is not toxic, only ClO3(-) would be a toxicity concern, but the levels transferred from rind to flesh are very low. In the case of fruit flesh directly exposed to ClO2 gas, only nontoxic Cl(-) was detected. This indicates that ClO2 gas that comes into contact with edible flesh would not pose a

  17. ASPEK PROSES DIAGENESIS TERHADAP SIFAT FISIK BATUPASIR FORMASI KEREK, DAERAH KALIPUTIH DAN SEKITARNYA, KECAMATAN SINGOROJO, KABUPATEN KENDAL, JAWA TENGAH

    Directory of Open Access Journals (Sweden)

    Vanny Hertanto Vahyu

    2012-07-01

    Nichols, 2009, and Packstone (Dunham, 1962; inNichols, 2009. Carbonate sandstones predominantly feldspar and quartz minerals and the lihtology names areCarbonate quartz wackes (Pettijhon, 1975; in Nichols, 2009, and Carbonate feldspathic arenite (Pettijhon, 1975;in Nichols, 2009. There are three minerals type of cement showed in carbonate sandstones which are calcite,chlorite and pyrite cements.The results of this research indicate that the diagenesis stages of carbonate sandstones showed cementation,dissolution, replacement, bioturbation, and compaction processes, and the more stages of diagenesis that occurs incarbonate sandstones will result in reduced porosity and progressively up at for formation stratigraphy excelsiorsediment rock assess its porosity is equal to 1%, 5%, 7% and 15% respectively. The type of cement minerals in thecarbonate sandstone influence porosity, especially in carbonate sandstone which there are chlorite cement that havesmall porosity value of 1%, 5% and 7%. The environment of diagenesis in carbonate sandstones that is phreatic andburial experienced of eogenesis process, mesogenesis process and telogenesis process.

  18. Grain size distribution, clay mineralogy and chemistry of bottom sediments from the outer Thermaikos Gulf, Aegean Sea, Greece

    Directory of Open Access Journals (Sweden)

    K.G. PEHLIVANOGLOU

    2012-12-01

    Full Text Available The Thermaikos Gulf constitutes the NW part of the North Aegean Sea and is limited eastward from the Chalkidiki Peninsula and westward from the Pieria Prefecture. Its plateau covers an area of 3,500 km2. The mechanisms responsible for the grain size distribution into the Gulf, the clay mineralogy and the chemistry of some bottom sediments from the outer Thermaikos Gulf, are examined. Source mixing during transportation, flocculation, differential settling processes and organic matter appear to be the main mechanisms for the distribution of clay minerals in shallow waters. All grain size fractions studied present a wide range of values confirming the extreme variations of the discharged load and the variability in marine processes. Plagioclases predominate over K-feldspars, while quartz is the most abundant mineral present. In addition, micas, chlorites, amphiboles and pyroxenes exist as primary and/or accessory minerals in all samples. Among clay minerals, illite predominates over smectite and smectite over chlorite (+ kaolinite. The ordered interstratified phase of I/S, with 30-35% S layers, is present in the 2-0.25µm fraction. The randomly interstratified phase of I/S, with 50% S layers, is present in the <0.25& micro; m fraction. On average the clay mineral content of the studied samples is: 48% I, 23% S, 17% Ch (+K and 12% others for the 2-0.25µm fraction and 50% I, 30% S and 20% Ch (+K for the <0.25 µm fraction. All these minerals are the weathering products of the rocks from the drainage basins of the rivers flowing into the Gulf, as well as of the Neogene and Quaternary unconsolidated sediments of the surrounding coasts. The terrigenous input, the water mass circulation and, to a lesser extent, the quality of the discharged material and the differential settling of grains, control the grain size distribution within the outer Thermaikos Gulf. The chemical composition of the analysed samples is generally in agreement with their mineral

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

    Science.gov (United States)

    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

    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

  20. Paleoenvironmental Implications of Clay Minerals at Yellowknife Bay, Gale Crater, Mars

    Science.gov (United States)

    Bristow, Thomas F.; Blake, David F.

    2014-01-01

    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 02l 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

  1. Clay minerals and geochemistry of the bottom sediments in the northwestern East China Sea

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Clay minerals of 34 sediments collected from the northwestern continental shelf of the East China Sea have been determined by X-ray diffraction analysis. The clay mineral distribution is mainly controlled by the sediment source and the dominant circulation pattern. The predominant clay mineral in our study area is illite comprising more than 67% of the whole clay fraction. The highest concentration of illite (>68%) is found in the southeastern offshore parts beyond the reach of terrigenous input from the Jeju Island. It means that these illites are largely transported by the Kuroshio Current from the South China Sea (SCS). Smectite is highly concentrated in the northwest middle part and in the outer-shelf mud patch. It seems to be due to the high supply of smectite transported from China where fine-grained sediments are discharged from modern and ancient Huanghe (Yellow) River. The relatively high abundant kaolinite is likely derived from the Changjiang (Yangtze) River via the Taiwan Warm Current. In contrast,large amounts of chlorite and high chlorite/kaolinite ratios occur in the northwestern area, reflecting the transportation by the Yellow Sea Coastal Current from the southern Yellow Sea. The discrimination diagrams clearly show that the sediments in the northwestern East China Sea are ultimately sourced from Chinese rivers, especially from the Huanghe River, whereas the sediment in the northeast part might come from the Jeju Island. The muddy sediments of the Changjiang River's submerged delta have much lower 87Sr/86Sr ratios (0.7162-0.7180) than those of the Shandong Peninsular mud wedge (0.7216-0.7249),which are supposed to be originated from the Huanghe River, suggesting the distribution pattern of 87Sr/86Sr ratios as a new tracer to discriminate the provenance of shelf sediments in the study area. The 87Sr/86Sr ratios of the outer-shelf muddy sediments ranged from 0.7169 to 0.7216 in a wide range and was between those of the Huanghe River and Changjiang

  2. Breakdown of Clays by Ectomycorrhizal Fungi Through Changes in Oxidation State of Iron

    Science.gov (United States)

    Arocena, J. M.; Velde, B.

    2012-04-01

    Organisms are known to play a significant role in the transformation of clay minerals in soils. In our earlier work on canola, barley and alfalfa, we reported that Glomus, an arbuscular mycorrhizae, selectively transformed biotite into 2:1 expanding clays through the oxidation of Fe (II) in biotite to Fe(III). In this presentation, we will share similar results on clay transformations mediated by ectomycorrhizal fungi colonizing the roots of coniferous trees. Clay samples were isolated from rhizosphere soils of sub-alpine fir (Abies lasiocarpa (Hook.) Nutt.) in northern British Columbia (Canada). Chemical and mineralogical properties of these soils had been reported in our earlier paper. In this study, we subjected the clay samples to iron X-ray Absorption Near Edge Spectroscopy (Fe-XANES) at the Canadian Light Source synchrotron facility in Saskatoon (Canada). Our initial results showed relatively higher amounts of Fe (III) than Fe(II) in clays collected from rhizosphere of Piloderma (an ectomycorrhizal fungus) compared to soils influenced by non-Piloderma species and Control (non-rhizosphere soil). Coupled with the results of X-ray diffraction (XRD) analysis, there seems to be a positive relationship between the relative amounts of Fe(III) and the 2:1 expanding clays. This relationship is consistent with our results on agricultural plants in laboratory experiments on biotites where we suggested that oxidation of Fe(II) to Fe(III) results in the formation of 2:1 expanding clays. In a related data set on chlorite alteration we observed that after dithionite-citrate-bicarbonate (DCB) treatment, the d-spacing of a slight portion of chloritic expanding clays shifted to higher angles indicating decreased d-spacing towards micaceous clays. The reductive process initiated through the action of the DCB treatment seems to indicate the collapsed of expandable clays upon the reduction of Fe(III) to Fe(II). Initial results from the Fe-XANES and XRD analysis of DCB

  3. Metamorphic and Ar/Ar geochronology constraints on the Alakeci shear zone: Implications for the extensional exhumation history of the northern Kazdag Massif, NW Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Bonev, N [Sofia University ' St. Kliment Ohridski' , Department of Geology and Paleontology, Sofia 1504 (Bulgaria); Beccaletto, L [BRGM Geological Survey/Geology of Sedimentary Basins, 45060 Orleans, Cedex 2 (France); Robyr, M [Geological Sciences Department, University of Texas, Austin, TX 787 12-0254 (United States); Monie, P [Geosciences, University of Montpellier 2, UMR 5243, 34095 Montpellier Cedex 5 (France)], E-mail: niki@gea.uni-sofia.bg

    2008-07-01

    The Kazdag Massif exposes a metamorphic dome in the Biga Peninsula of northwest Turkey. An extensional origin has been proposed for the dome, limited on both flanks by detachments and/or shear zones. The northern flank is bounded by the extensional Alakeci Shear Zone (ASZ), whose P-T-t path is still poorly known. We therefore focus on its metamorphic conditions and related temporal history to precise its tectono-metamorphic evolution. The local tectonostratigraphy in structurally ascending order comprises: (i) the high-grade metamorphic core rocks of the Kazdag Massif (gneisses and micaschists intercalated with amphibolites and marbles); (ii) the two kilometer-thick ASZ; (iii) the overlaying unmetamorphosed pre-Cenomanian accretionary Cetmi melange; and (iv) Neogene sedimentary and volcanic cover rocks. ASZ mylonites were derived from both the core rocks and the melange lithologies. From the north to the south the mylonitic fabrics in the ASZ depict a top-to-the N-NNE shearing, parallel to the NNE-plunging stretching lineation and NNW-dipping mylonitic foliation. This geometry implies normal sense movement i.e. north-side down-dip extensional displacement along this flank of the Kazdag Massif. The northward transition from ductile to brittle-ductile regime through the ASZ shows that the deformation occurred at decreasing temperatures and degree of metamorphism. The paragenesis in equilibrium within the mylonitic gneisses and schists contains Qtz + Fs + Ms + Bt + Grt {+-} St {+-} Sill, with late retrogressive chlorite after biotite and garnet. Four samples of ASZ rocks yielded pressures between 6.9-5.7 kbar and temperatures between 706-587 deg. C. Three samples from the mylonitic rocks supplied in situ isochron {sup 36}Ar/{sup 40}Ar mica ages between 31.2-24.2 Ma, which we interpret to date the cooling of the mylonites following the P-T decrease across the ASZ. The metamorphic and structural results support the extensional character of the ASZ, and sketch transition

  4. Grain-rimming kaolinite in Permian Rotliegend reservoir rocks

    Science.gov (United States)

    Waldmann, Svenja; Gaupp, Reinhard

    2016-04-01

    Upper Rotliegend sediments of Permian age from the northeast Netherlands show moderate to good reservoir qualities. The predominant control is by the presence of authigenic grain-rimming kaolinite, which has a negative, but in some parts also a positive, effect on reservoir quality. To better understand the formation and distribution of grain-rimming kaolinite, reservoir rocks were studied in terms of composition and diagenetic processes. Petrographic evidence, summarized as a paragenetic sequence, is integrated with geochemical modeling results to identify early mesodiagenetic water-rock interactions under the participation of gases, i.e., CO2 and H2S, released from underlying Carboniferous source rocks. The sediments investigated were deposited at varying distance from the southern flank of the Southern Permian Basin. Sediments near the basin margin are mainly attributed to a fluvial environment and comprise medium to coarse-grained sandstones and conglomerates. There, vermicular kaolinite occurs with a lath-like structure. Distal to the basin margin, mainly in sandstones intercalated with fine-grained playa sediments, comparatively high amounts of grain-rimming kaolinite occur. There, the presence of this mineral has a significant influence on the rock properties and the reservoir quality. Geochemical modeling suggests that the formation of such kaolinites cannot be explained exclusively by in situ feldspar dissolution. The modeling results support evidence that kaolinite can be formed from precursor clay minerals under the presence of CO2-rich formation waters. Such clay minerals could be corrensite, smectite-chlorite mixed-layer minerals, or chlorite that is potentially present in Rotliegend sediments during early diagenesis. Furthermore, the geochemical modeling can reflect several mineral reactions that were identified from petrographic analysis such as the formation of illite and kaolinite at the expense of feldspar dissolution and consequent silica

  5. Remote Sensing, Geology and Geochemistry on the GVIII Uranium Mineralization, Gabal Gattar, North Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    GVIII- uranium occurrence of Gabal Gattar is located at the intersection of Lat. 27° 05' 56and Long. 33° 16' 33to the south of GH-uranium occurrence. This occurrence is hosted in the alkali feldspar granite of Gabal Gattar. It is dissected by NNE-SSW, ENE-WSW and NW-SE faults and fractures. The granite is strongly altered in the zones of these faults and fractures. This granite is composed of K-feldspars, quartz, plagioclase and biotite as essential minerals and zircon, apatite, fluorite as accessories. The secondary minerals are chlorite, sericite, muscovite and iron oxides. The main alterations along the fault and fracture zones are hematitization, silicification, kaolintiization, chloritization and fluoritization that increase at the zones of intersection.The Advanced Spacebome Thermal Emission and Reflection Radiometer (ASTER) discriminated and mapped the hematitized zones in the studied granitic rocks predicting iron oxides as pathfinder minerals that be helpful in localizing high uranium concentration. The compilated and integrated data as alteration zones, geological and structural features using Geographic Information System (GIS) played an important role in correlating, manipulating, visualizing and extracting the information getting a better result for interpretation and evaluation of this occurrence. The study granite is geochemically, alkali- feldspar granite to syenogranite originated from weakly peraluminous magma of alkaline affinity and of within plate tectonic setting due to crustal relaxation. This granite shows many geochemical characterestics similar to the A-type granite, high contents of SiO2, (Na2O + K2O), Rb, Nb, Y, low contents of MgO, CaO and Sr and apparently F-rich granite.Radiometric measurements of GVIII U-occurrence show that the study granite records uranium values between 15 and 28 ppm, while the anomalies record uranium values range from 400 to more than 30000 ppm. Surfacial yellow secondary uranium mineralization was

  6. Glass shards, pumice fragments and volcanic aerosol particles - diagenesis a recorder of volcanic activity?

    Science.gov (United States)

    Obenholzner, J. H.; Schroettner, H.; Poelt, P.; Delgado, H.

    2003-04-01

    Detailed SEM/EDS studies of Triassic (Southern Alps, A, I, Sl) and Miocene (Mixteca Alta, Mexico) tuffs revealed that volcanic glass shards can be replaced by zeolites (analcite), chlorites and smectites preserving the shape of primary shards (1). The Triassic pyroclastic deposits have been incorporated in the pre-Alpine burial diagenesis, the Miocene pyroclastic deposits are bentonites. The volcanologist is impressed by the circumstances that million years old pyroclast relict textures can be sized. Shape parameters obtained by image analysis can be compared with much younger pyroclastic deposits (2). Both deposits have not been effected by shearing. The alteration of pumice fragments of Triassic age is not a simple replacement process. Intergrowth of different illites and chlorites and probably vesicle filling by SiO2 and subsequent overgrowth make a reconstruction sometimes difficult. These processes are accompanied by the formation of REE-, Y- and Zr-bearing minerals as well as with the alteration of zircons. Studies of recently erupted ash from Popocatepetl volcano reveal the presence of a variety of µm-sized contact-metamorphosed clasts being a part of the volcanic ash (3). Such clasts should be present in many older pyroclastic deposits, especially where volcanoes had been situated on massive sedimentary units providing contact metamorphism in the realm of a magma chamber or during magma ascent. Volcanic aerosol particles collected in 1997 from the passively degassing plume of Popocatepetl volcano revealed in FESEM/EDS analysis (H. Schroettner and P. Poelt) a wide spectrum of fluffy, spherical and coagulated spherical particles (µm-sized). Under pre-vacuum conditions they remained stable for ca. 3 years (3). In nature the fate of these particles in the atmosphere is unknown. Are there relicts in marine, lacustrine sediments and ice cores, which could be used as proxies of volcanic activity? (1) Obenholzner &Heiken,1999. Ann.Naturhist.Mus.Wien, 100 A, 13

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

    Science.gov (United States)

    Wang, H.

    2014-12-01

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

  8. Structures, microfabrics and textures of the Cordilleran-type Rechnitz metamorphic core complex, Eastern Alps☆

    Science.gov (United States)

    Cao, Shuyun; Neubauer, Franz; Bernroider, Manfred; Liu, Junlai; Genser, Johann

    2013-01-01

    Rechnitz window group represents a Cordilleran-style metamorphic core complex, which is almost entirely located within nearly contemporaneous Neogene sediments at the transition zone between the Eastern Alps and the Neogene Pannonian basin. Two tectonic units are distinguished within the Rechnitz metamorphic core complex (RMCC): (1) a lower unit mainly composed of Mesozoic metasediments, and (2) an upper unit mainly composed of ophiolite remnants. Both units are metamorphosed within greenschist facies conditions during earliest Miocene followed by exhumation and cooling. The internal structure of the RMCC is characterized by the following succession of structure-forming events: (1) blueschist relics of Paleocene/Eocene age formed as a result of subduction (D1), (2) ductile nappe stacking (D2) of an ophiolite nappe over a distant passive margin succession (ca. E–W to WNW–ESE oriented stretching lineation), (3) greenschist facies-grade metamorphism annealing dominant in the lower unit, and (4) ductile low-angle normal faulting (D3) (with mainly NE–SW oriented stretching lineation), and (5) ca. E to NE-vergent folding (D4). The microfabrics are related to mostly ductile nappe stacking to ductile low-angle normal faulting. Paleopiezometry in conjunction with P–T estimates yield high strain rates of 10− 11 to 10− 13 s− 1, depending on the temperature (400–350 °C) and choice of piezometer and flow law calibration. Progressive microstructures and texture analysis indicate an overprint of the high-temperature fabrics (D2) by the low-temperature deformation (D3). Phengitic mica from the Paleocene/Eocene high-pressure metamorphism remained stable during D2 ductile deformation as well as preserved within late stages of final sub-greenschist facies shearing. Chlorite geothermometry yields two temperature groups, 376–328 °C, and 306–132 °C. Chlorite is seemingly accessible to late-stage resetting. The RMCC underwent an earlier large-scale coaxial

  9. Environmentálne aspekty transformácie nízko-sulfidického postflotačného kalu na antropogénnu pôdu (Smolník, Slovensko

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    Mangová Kristína

    2015-12-01

    Full Text Available An anthropogenic soil developed on the mine tailing impoundment in Smolník was studied to document a transformation of post flotation mud (tailings to the soil. The tailing can be characterised as fine sand to silt grain size milled wall rock mineral matter composed by quartz, mica, chlorite, and siderite with low pyrite content. Surface of the tailing impoundment have been covered by a 10–15 cm thick layer of wood-waste material and forested by pine-plants. Two soil horizons A-topsoil (humus and B-subsoil horizons have been recognised above the post flotation mud (tailings. Oxidation of pyrite and “acid” generation, leach and dissolution of the minerals and precipitation of iron oxy-hydroxides have been main processes beginning the tailings alteration. The processes were indicated by yellowish colours and raised homogeneity of the subsoil tailings. Variegated and relative high content of organic matter (TOC ≈ 3–15 wt. %, neutral to low acid pH (6.01–7.25, decreased amount of carbonates but a saturation with the bases (CEC: 20–80 mmol.100 g-1, especially with Ca2+ characterised A horizon. Contents of 0.5 M HCl extractable fractions of Cu, Pb, Zn and As were locally higher as in the sub-soils, respective as in the tailings/substrate. There were favourable conditions to Fe oxide precipitation as indicated contents of oxalate extractable Fe oxide (FeOX in range 1.3–6.1 wt. % in the soil profile. Besides the iron oxide precipitation the remobilization of metals has been limited by other factors, mainly by organic matter accumulation and by humus formation which actively “aggregated” mineral particles in A horizon. Indicated mixed-layered vermiculite-chlorite or vermiculite-illite minerals formation also suggested a role of organic matter in the soil-pH decrease and primary phyllosilicates transformation. Soil-forming process was positively “accelerated” by fine-milled character and primary mineralogy (pyrite < 5 wt. % of the

  10. Slab melting and magma formation beneath the southern Cascade arc

    Science.gov (United States)

    Walowski, K. J.; Wallace, P. J.; Clynne, M. A.; Rasmussen, D. J.; Weis, D.

    2016-07-01

    The processes that drive magma formation beneath the Cascade arc and other warm-slab subduction zones have been debated because young oceanic crust is predicted to largely dehydrate beneath the forearc during subduction. In addition, geochemical variability along strike in the Cascades has led to contrasting interpretations about the role of volatiles in magma generation. Here, we focus on the Lassen segment of the Cascade arc, where previous work has demonstrated across-arc geochemical variations related to subduction enrichment, and H-isotope data suggest that H2O in basaltic magmas is derived from the final breakdown of chlorite in the mantle portion of the slab. We use naturally glassy, olivine-hosted melt inclusions (MI) from the tephra deposits of eight primitive (MgO > 7 wt%) basaltic cinder cones to quantify the pre-eruptive volatile contents of mantle-derived melts in this region. The melt inclusions have B concentrations and isotope ratios that are similar to mid-ocean ridge basalt (MORB), suggesting extensive dehydration of the downgoing plate prior to reaching sub-arc depths and little input of slab-derived B into the mantle wedge. However, correlations of volatile and trace element ratios (H2O/Ce, Cl/Nb, Sr/Nd) in the melt inclusions demonstrate that geochemical variability is the result of variable addition of a hydrous subduction component to the mantle wedge. Furthermore, correlations between subduction component tracers and radiogenic isotope ratios show that the subduction component has less radiogenic Sr and Pb than the Lassen sub-arc mantle, which can be explained by melting of subducted Gorda MORB beneath the arc. Agreement between pMELTS melting models and melt inclusion volatile, major, and trace element data suggests that hydrous slab melt addition to the mantle wedge can produce the range in primitive compositions erupted in the Lassen region. Our results provide further evidence that chlorite-derived fluids from the mantle portion of the

  11. Shear-hosted base metal mineralisation at the Dana Peaks, Murchison Mountains, Fiordland, New Zealand

    International Nuclear Information System (INIS)

    Darran Suite dioritic, tonalitic and granodioritic plutonic rocks and schistose Loch Burn Formation volcaniclastic rocks in the central Murchison Mountains at the Dana Peaks have been affected by widespread biotite-sericite-chlorite-albite-quartz-pyrite ± carbonate ± epidote/clinozoisite ± titanite/rutile ± actinolite alteration. More intense, paler coloured sericite-albite-quartz-pyrite ± carbonate alteration is concentrated along orange weathered shear zones. Alteration assemblages are transitional between those commonly referred to as propylitic, potassic and phyllic. Altered rocks contain anomalous concentrations of copper, lead, zinc and silver over an area of c. 2.56 km. Metal concentrations 2-5 times those typical of Darran Suite plutonic rocks and the Loch Burn Formation are commonly associated with more extensive weak to moderate intensity alteration. Higher metal grades up to c. 0.5% copper, 1% zinc, 1.3% lead and 30 ppm silver are concentrated in or adjacent to the 1-5 m wide, more intensely altered shear zones which contain entrained lenses of pyritised country rock, breccias and quartz ± K-feldspar ± chlorite ± carbonate ± hematite ± tourmaline veins. Some mineralised rocks also contain traces of tungsten (2-7 ppm), arsenic (<5-35 ppm) and tellurium (0.2-5.4 ppm). Most samples lack detectable molybdenum (<3 ppm), gold (<0.004 ppm) or bismuth (<0.2 ppm), with atypical higher values (40, 0.03 and 50 ppm, respectively) generally restricted to the most intensely altered and/or deformed rocks. The mineralised rocks show a close spatial and temporal relationship with several narrow ductile shear zones that probably developed in the Early Cretaceous between c. 128 and 110 Ma. Mineralised shear zones form minor splays off larger shear zones that are part of a major intra-arc fault system, active along or near the boundary between inboard and outboard parts of the Median Batholith at this time. Traces of similar lead mineralisation are present at the

  12. Radiation chemical effects in the near-field environment of a radwaste repository: {gamma} radiolysis in 6 molal NaCl solutions; Strahlenchemische Effekte im Endlagernahbereich: {gamma}-Radiolyse in 6 molarer NaCl-Loesung

    Energy Technology Data Exchange (ETDEWEB)

    Kelm, M.; Bohnert, E.

    1997-12-01

    The radiation emitted from high-level radioactive wastes in a radwaste repository causes radiolysis products to be formed in brines resulting from water intrusion. The products may alter via redox and complexing reactions the mobilisation processes of radionuclides. The major products of {gamma} radiolysis determined in 6 molal NaCl solution as a function of radiation dose are hydrogen, oxygen, and chlorate. Hypochlorite and chlorite were found to have concentrations in the {mu}Mol/kg range. There was no dependence on dose rate. For the experiments under atmospheric pressure, which allowed radiolytic gas to escape from the solution, the G values measured are 0.46 (H{sub 2}), 0.16 (O{sub 2}), and 0.074 (ClO{sub 3}). In pressurized experiments, with radiolytic gas remaining contained in the solution, the radiolytic effect was much smaller. After approx. 100 days, at a dose of about 2 MGy, gas equilibrium concentrations of some mMol/kg were measured. The results can be qualitatively described by a system of parallel running reaction rate equations. As to quantitative analysis, the reaction model needs to be refined. (orig./CB) [Deutsch] Die Strahlung von hochradioaktiven Abfaellen in einem Endlager im Salz hat zur Folge, dass bei einem Wasserzutritt in den entstehenden Laugen Radiolyseprodukte gebildet werden. Die Radiolyseprodukte koennen durch Redox- und Komplexierungsreaktionen die Mobilisierbarkeit von Radionukliden veraendern. Als Hauptprodukte der {gamma}-Radiolyse wurden in 6 molaler NaCl-Loesung Wasserstoff, Sauerstoff und Chlorat in Abhaengigkeit von der Dosis bestimmt. Hypochlorit und Chlorit erreichten nur Konzentrationen im {mu}Mol/kg-Bereich. Eine Dosisleistungsabhaengigkeit war nicht festzustellen. Bei den Experimenten unter Normaldruck, bei denen die Radiolysegase aus der Loesung entweichen konnten, betrugen die G-Werte 0.46 (H{sub 2}), 0,16 (O{sub 2}) und 0,074 (ClO{sub 3}{sup -}). Bei den Experimenten unter Druck wurden die Radiolysegase in Loesung

  13. Mineralogía y génesis de la fracción fina de la serie de El Rinconcillo (formaciones Flysch del Campo de Gibraltar. SW de España

    Directory of Open Access Journals (Sweden)

    Carrasco, F.

    1987-04-01

    Full Text Available The stratigraphic sequence of El Rinconcillo belong to the Algeciras Unit. Illite, kaolinite, chlorite and interstratified illite-smectite are common minerals for materials of this Unit, but a high proportion of Fe-Al smectites and sporadic presence of palygorskite is characteristic of the series of El Rinconcillo in relation to the others studied in Northern Africa and Southwestern Spain. Illite, kaolinite and chlorite are considered to be inherited minerals. Smectides and interestratified illite-smectite are also inherited in the turbidites but they were formed in the source area by transformation from illite under different weathering degree. Finally, the formation of palygorskite in the Middle Eocene carbonatic turbidites accompanied by many smectide, and no kaolinite, is difficult to explain in relation with turbiditic materials. It is more feasible to suppose a removal process that implicates the existence of a previous clay sediment in which such association -palygorskite + smectite- took place by transformation and/or by neoformation.La serie de El Rinconcillo, atribuida a la Unidad de Algeciras, presenta variaciones mineralógicas notables respecto a las series "tipo" definidas en esta Unidad tanto en el norte de Africa como en el suroeste de España. Aunque en gran parte la mineralogía es común con otras series de esta Unidad (ilita, caolinita, clorita, interestratificados I-E, se diferencia no obstante, por la elevada proporción de esmectita Fe-Al y la presencia esporádica de paligorskita. Ilita, caolinta y clorita, se consideran minerales heredados. La esmectita y los interestratificados I-E son también heredados en las turbiditas, procedentes de la transformación de la ilita en el área fuente bajo diferente grado de meteorización. Finalmente, la formación de paligorskita en las turbidítas calcáreas del Eoceno medio acompañada por esmectita y la ausencia de caolinita en este tramo, es difícil de explicar en relación con

  14. Reduction and immobilization of hexavalent chromium by microbially reduced Fe-bearing clay minerals

    Science.gov (United States)

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

    2014-05-01

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

  15. Recent advances in the study of H environments and behavior in minerals using neutron powder diffraction

    Science.gov (United States)

    Welch, M. D.

    2002-12-01

    It is now possible to probe the structural environments and behavior of H atoms directly in complex minerals such as amphiboles, micas, chlorites and humites using neutron powder diffraction, in some cases as a function of pressure and/or temperature. A combination of high neutron flux and increased detector sensitivity and size offers the chance to see details of H behaviour. In the last year or so the advent of new gasket designs for the Paris-Edinburgh pressure cell allow the use of ethanol/methanol (EtOD/MeOD) as a pressure medium, removing peak broadening arising from deviatoric stress that occurs above 3 GPa for the standard fluorinert pressure medium. Essentially hydrostatic conditions obtain with EtOD/MeOD to 8 GPa at 298 K. A further recent development has been the design of a high P-T module for use with the Paris-Edinburgh cell. These technological improvements in pressure-cell design now allow us to make meaningful correlations between OH vibrational spectra collected at high P and/or T and detailed structural information on H behaviour obtained from neutron diffraction under similar conditions. In this talk I shall discuss recent neutron diffraction experiments on the effect of pressure upon hydrogen bonding in deuterated chlorite to 5 GPa (298 K), and a high P-T study of hydrogen bonding in deuterated brucite to 7 GPa, 1100 K. These two studies illustrate how far high-pressure neutron diffraction has come in the last 5 years. Finally, I shall describe a neutron powder diffraction study (ambient conditions) of leucophoenicite, Mn7Si3O12(OH)2, a close structural analogue of Phase-B and Superhydrous-B: the structure of leucophoenicite is topologically identical to the hydrous sheet of Phase-B and similar to that of Superhydrous-B. For various reasons it was not possible to deuterate the sample. Nonetheless, the two distinct H atoms were approximately located in difference-Fourier maps and then refined isotropically. The H positions in Phase-B were only

  16. Effects of chemical alteration on fracture mechanical properties in hydrothermal systems

    Science.gov (United States)

    Callahan, O. A.; Eichhubl, P.; Olson, J. E.

    2015-12-01

    Fault and fracture networks often control the distribution of fluids and heat in hydrothermal and epithermal systems, and in related geothermal and mineral resources. Additional chemical influences on conduit evolution are well documented, with dissolution and precipitation of mineral species potentially changing the permeability of fault-facture networks. Less well understood are the impacts of chemical alteration on the mechanical properties governing fracture growth and fracture network geometry. We use double-torsion (DT) load relaxation tests under ambient air conditions to measure the mode-I fracture toughness (KIC) and subcritical fracture growth index (SCI) of variably altered rock samples obtained from outcrop in Dixie Valley, NV. Samples from southern Dixie Valley include 1) weakly altered granite, characterized by minor sericite in plagioclase, albitization and vacuolization of feldspars, and incomplete replacement of biotite with chlorite, and 2) granite from an area of locally intense propylitic alteration with chlorite-calcite-hematite-epidote assemblages. We also evaluated samples of completely silicified gabbro obtained from the Dixie Comstock epithermal gold deposit. In the weakly altered granite KIC and SCI are 1.3 ±0.2 MPam1/2 (n=8) and 59 ±25 (n=29), respectively. In the propylitic assemblage KIC is reduced to 0.6 ±0.1 MPam1/2 (n=11), and the SCI increased to 75 ±36 (n = 33). In both cases, the altered materials have lower fracture toughness and higher SCI than is reported for common geomechanical standards such as Westerly Granite (KIC ~1.7 MPam1/2; SCI ~48). Preliminary analysis of the silicified gabbro shows a significant increase in fracture toughness, 3.6 ±0.4 MPam1/2 (n=2), and SCI, 102 ±45 (n=19), compared to published values for gabbro (2.9 MPam1/2 and SCI = 32). These results suggest that mineralogical and textural changes associated with different alteration assemblages may result in spatially variable rates of fracture

  17. Mineralogía y génesis de las arcillas de las unidades del Campo de Gibraltar. V. Unidad de Bolonia

    Directory of Open Access Journals (Sweden)

    Ruiz Cruz, M. D.

    1990-04-01

    Full Text Available The mineralogical results of the Bolonia Unit are analysed in the work. The Cabrito-l section is characterized by the mineralogical association kaolinite-illite-interestratified I-S, and is similar to the section of Punta Tarifa series of the Algeciras Unit. The Pulido section, characterized by the mineralogical association (kaolinite-illite-chlorite, may be considered as the most distal zone of the «areniscoso-micaceo» flysch of the Algeciras Unit. The most significant difference between the fine fractions of these Units is the remarkable development, in the Bolonia Unit, of authigenic chlorites, whose composition shows a diagenetic environment rich in Fe and Mg. On the other hand, the mineralogical composition of the fine fraction has made possible the identification in the Bolonia Unit, not only the «areniscas del Aljibe» levels, but also clay levels of Aljibe Unit, which has not been noticed until now. These mineralogical and lithological aspects lead to consider the Bolonia Unit as an intermediate Unit between the Algeciras and the Aljibe ones.En este trabajo se recogen los resultados obtenidos a partir del estudio mineralógico de la Unidad de Bolonia. De los perfiles estudiados, el del Cabrito, caracterizado por la asociación mineralógica caolinita-ilita, interestratificados I-E, es similar en gran medida a la serie tipo punta Tarifa de la Unidad de Algeciras. El perfil del Pulido, caracterizado por la asociación (caolinita-ilita-clorita puede interpretarse como la parte más distal del flysch areniscoso-micáceo de la Unidad de Algeciras. La diferencia más notable en la mineralogía de la fracción fina entre ambas Unidades se refiere al desarrollo notable, en Bolonia, de cloritas autigénicas, cuya composición indica un medio diagenético rico en Fe y Mg. Por otra parte, la mineralogía de la fracción fina ha permitido identificar en la Unidad de Bolonia no sólo los niveles de areniscas del Aljibe sino tambi

  18. Numerical Simulation of Extent of Carbon Dioxide Plume Injected in the Gyeongsang Basin, Korea

    Science.gov (United States)

    Kihm, J.; Park, S.; Kim, J.

    2012-12-01

    A series of thermo-hydro-chemical numerical simulations was performed to evaluate extent of carbon dioxide plume injected in the Gyeongsang Basin, which is one of the prospective onshore sedimentary basins for geologic storage of carbon dioxide in Korea. The carbon dioxide plume extent is an important factor in estimating storage efficiency and thus storage capacity of carbon dioxide in a storage formation because it represents an actual volume of the storage formation, which is occupied by injected carbon dioxide. The carbon dioxide plume extent is also an essential component in risk analysis of geologic storage of carbon dioxide because most of thermo-hydro-mechanical-chemical responses to carbon dioxide injection occur within it. To evaluate impacts of injection scenarios (i.e., injection rate and period) of carbon dioxide and geological conditions (i.e., thickness and depth) and hydrogeochemical properties (i.e., porosity, intrinsic permeability, salt concentration in groundwater, and volume fraction of chlorite) of a storage formation on the carbon dioxide plume extent, a series of sensitivity tests was also performed. The numerical simulation results show that the carbon dioxide plume extent is significantly affected by such injection scenarios, geological conditions, and hydrogeochemical properties. The carbon dioxide plume extent increases as the injection rate (with a constant injection period) increases, and this trend does not change with time. The carbon dioxide plume extent decreases as the injection period (with a constant total injection amount) increases until about 50 years, while it is not sensitive to the injection period after about 50 years. The carbon dioxide plume extent also decreases as the thickness increases until about 100 years, while it is not sensitive to the thickness after about 100 years. In contrast, the carbon dioxide plume extent decreases as the depth increases, and this trend is intensified with time. On the other hand, the

  19. Reconstruction of seawater chemistry from deeply subducted oceanic crust; hydrogen and oxygen isotope of lawsonite eclogites preserving pillow structure

    Science.gov (United States)

    Hamabata, D., VI; Masuyama, Y.; Tomiyasu, F.; Ueno, Y.; Yui, T. F.; Okamoto, K.

    2014-12-01

    In order to understand evolution of life, change of seawater chemistry from Hadean, Archean to present is significant. Pillow structure is well-preserved in the Archean greenstone belt (e.g. Komiya et al., 1999). Oxygen and hydrogen isotope of rims in the pillow is useful conventional tool to decipher chemistry of Paleao-seawater from Archean to Present. However, Archean greenstone belt suffered regional metamorphism from greenschist to Amphibolite facies conditions. Therefore, it is necessary to testify the validity of pillow chemistry from recent (Phanerozoic) metamorphosed greenstone. We have systematically collected pillowed greenstone from blueschist and eclogites. Two eclogite exhibiting pillow structures were chosen for oxygen and hydrogen isotope analysis. One is from Corsica (lawsonite eclogite collected with Dr. Alberto Vidale Barbarone) and another is from Cazadero, Franciscan belt (collected by Dr. Tatsuki Tsujimori). The both are ascribed as MORB from major and trace bulk chemistry and Ca is rich in the core and Na is poor in the rims. The former exhibits garnet, omphacite, lawsonite, and glacophane. Phengite is in core of the pillow and chlorite is in the rims. In the latter, besides garnet, omphacite, epdiote and glaucophane, chlorite is recognized with phengite in the core. Glaucophane is richer in the rims from the both samples, therefore istope analysis of glaucophane was done. Mineral separation was carefully done using micro-mill, heavy liquid and isodynamic separator. 20 mg specimens were used for oxygen isotope analysis and 2mg were for hydrogen analysis. δ18O of the all analysis (7.7 to 8.3) is within the range of unaltered igneous oceanic crust and high temperature hydrothermal alteration although rims (8.3 for Franciscan and 8.0 for Corsica) are higher than cores (7.7 for Franciscan and Corsica). δD data is also consistent with hydrothermal alteration. It is relative higher in core from the Corsica and Franciscan (-45 and -56) than of the

  20. 2.9-1.9 Ga paleoalterations of Archean granitic basement of the Franceville basin (Gabon)

    Science.gov (United States)

    Mouélé, Idalina Moubiya; Dudoignon, Patrick; El Albani, Abderrazak; Meunier, Alain; Boulvais, Philippe; Gauthier-Lafaye, François; Paquette, Jean-Louis; Martin, Hervé; Cuney, Michel

    2014-09-01

    The Archean granitoids in the Kiéné area, Gabon, are overlained by the Paleoproterozoic sediments of the Franceville basin (2.1 Ga). The basin is known for its high-grade uranium deposits among which some have been forming natural nuclear fission reactors. Most of the studies were dedicated to the FA-FB Paleoproterozoic sediments hosting these uranium deposits. Little is known on the Archean basement itself and specifically on the hydrous alteration events it experienced before and after the sediment deposition. The present work is focused on their petrographical, mineralogical and geochemical characterization. Dating the successive alteration events has been attempted on altered monazite crystals. Rocks in different alteration states have been sampled from eight drill cores crosscutting the Archean - Paleoproterozoic unconformity. The Archean granitoids observed in the deepest levels exhibit typical petrographical features of a propylitic alteration while they are intensely illitized up to the unconformity. The propylitic alteration is mainly pervasive but the original texture of the granitoïds is conserved in spite of the formation of new minerals: Mg-chlorite, allanite and epidote forming a typical paragenesis. The illitic alteration is much more invasive near the unconformity. The illitization process leads to the replacement of feldspars and the corrosion of quartz crysals by an illitic matrix while the ferromagnesian minerals are pseudomorphosed by a Fe-chlorite + phengite + hematite assemblage. The final fluid-rock interaction step is marked by fissural deposits of calcite and anhydrite. The δ13C isotopic data show that the fissural carbonates precipitated from diagenetic fluids enriched carbon products deriving from the maturation of organic matter. The U-Pb isotopic analyzes performed on monazite crystals have dated three distinct events: 3.0-2.9 Ga (magmatic), 2.6 Ga (propylitic alteration) and 1.9 Ga (diagenetic illitization). The calculation of

  1. An integrated multidisciplinary re-evaluation of the geothermal system at Valles Caldera, New Mexico, using an immersive three-dimensional (3D) visualization environment

    Science.gov (United States)

    Fowler, A.; Bennett, S. E.; Wildgoose, M.; Cantwell, C.; Elliott, A. J.

    2012-12-01

    We describe an approach to explore the spatial relationships of a geothermal resource by examining diverse geological, geophysical, and geochemical data sets using the immersive 3-dimensional (3D) visualization capabilities of the UC Davis Keck Center for Active Visualization in the Earth Sciences (KeckCAVES). The KeckCAVES is a facility where stereoscopic images are projected onto four, surfaces (three walls and a floor), which the user perceives as a seamless 3D image of the data. The user can manipulate and interact with the data, allowing a more intuitive interpretation of data set relationships than is possible with traditional 2-dimensional techniques. We incorporate multiple data sets of the geothermal system at Valles Caldera, New Mexico: topography, lithology, faults, temperature, alteration mineralogy, and magnetotellurics. With the ability to rapidly and intuitively observe data relationships, we are able to efficiently and rapidly draw conclusions about the subsurface architecture of the Valles Caldera geothermal system. We identify two high-temperature anomalies, one that corresponds with normal faults along the western caldera ring fracture, and one that with the resurgent dome. A cold-temperature anomaly identified adjacent to the resurgent dome high-temperature anomaly appears to relate to a fault controlled graben valley that acts as a recharge zone, likely funneling cold meteoric water into the subsurface along normal faults observed on published maps and cross sections. These high-temperature anomalies broadly correspond to subsurface regions where previous magnetotelluric studies have identified low apparent resistivity. Existing hot springs in the Sulfur Springs area correspond to the only location where our modeled 100°C isotherm intersects the ground surface. Correlation between the first occurrence of key alteration minerals (pyrite, chlorite, epidote) in previously drilled boreholes and our temperature model vary, with chlorite showing a

  2. Metamorphism of mineral matter in coal from the Bukit Asam deposit, south Sumatra, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Susilawati, Rita; Ward, Colin R.

    2006-10-02

    The coal of the Miocene Bukit Asam deposit in south Sumatra is mostly sub-bituminous in rank, consistent with regional trends due to burial processes. However, effects associated with Plio-Pleistocene igneous intrusions have produced coal with vitrinite reflectance up to at least 4.17% (anthracite) in different parts of the deposit. The un-metamorphosed to slightly metamorphosed coals, with Rv{sub max} values of 0.45-0.65%, contain a mineral assemblage made up almost entirely of well-ordered kaolinite and quartz. The more strongly heat-affected coals, with Rv{sub max} values of more than 1.0%, are dominated by irregularly and regularly interstratified illite/smectite, poorly crystallized kaolinite and paragonite (Na mica), with chlorite in some of the anthracite materials. Kaolinite is abundant in the partings of the lower-rank coals, but is absent from the partings in the higher-rank areas, even at similar horizons in the same coal seam. Regularly interstratified illite/smectite, which is totally absent from the partings in the lower-rank coals, dominates the mineralogy in the partings associated with the higher-rank coal beds. A number of reactions involving the alteration of silicate minerals appear to have occurred in both the coal and the associated non-coal lithologies during the thermal metamorphism generated by the intrusions. The most prominent involve the disappearance of kaolinite, the appearance of irregularly interstratified illite/smectite, and the formation of regular I/S, paragonite and chlorite. Although regular I/S is identified in all of the non-coal partings associated with the higher-rank coals, illite/smectite with an ordered structure is only recognised in the coal samples collected from near the bases of the seams. The I/S in the coal samples adjacent to the floor of the highest rank seam also appears to have a greater proportion of illitic components. The availability of sodium and other non-mineral inorganic elements in the original coal

  3. Implications of spinel compositions for the petrotectonic history of abyssal peridotite from Southwest Indian Ridge (SWIR)

    Science.gov (United States)

    Chen, T.; Jin, Z.; Wang, Y.; Tao, C.

    2012-12-01

    Abyssal peridotites generate at mid-ocean ridges. Lherzolite and harzburgite are the main rock types of peridotites in the uppermost mantle. The lherzolite subtype, less depleted and less common in ophiolites, characterizes mantle diapirs and slow-spreading ridges. Along the Earth's mid-ocean ridges, abyssal peridotites undergo hydration reactions to become serpentinite minerals, especially in slow to ultraslow spreading mid-ocean ridges. Spinel is common in small quantities in peridotites, and its compositions have often been used as petrogenetic indicators [1]. The Southwest Indian Ridge (SWIR) is one of the two ultraslow spreading ridges in the world. The studied serpentinized peridotite sample was collected by the 21st Voyage of the Chinese oceanic research ship Dayang Yihao (aka Ocean No. 1) from a hydrothermal field (63.5°E, 28.0°S, and 3660 m deep) in SWIR. The studied spinels in serpentinized lherzolite have four zones with different compositions: relic, unaltered core is magmatic Al-spinels; micro- to nano- sized ferrichromite zoned particles; narrow and discontinuous magnetite rim; and chlorite aureoles. The values Cr# of the primary Al-spinels indicate the range of melting for abyssal peridotites from SWIR extends from ~4% to ~7% [2]. The alteration rims of ferrichromite have a chemical composition characterized by Fe enrichment and Cr# increase indicating chromite altered under greenschist-amphibolite facies. Magnetites formed in syn- and post- serpentinization. Chlorite (clinochlore) formed at the boundary and crack of spinel indicating it had undergone with low-temperature MgO- and SiO2-rich hydrothermal fluids [3]. It suggests that serpentinized lherzolite from SWIR had undergone poly-stage hydration reactions with a wide range of temperature. Acknowledgments: EMPA experiment was carried out by Xihao Zhu and Shu Zheng in The Second Institute of Oceanography and China University of Geosciences, respectively. The work was supported by NSFC

  4. Mesozoic metamorphism and its tectonic implication along the Solonker suture zone in central Inner Mongolia, China

    Science.gov (United States)

    Zhang, Jinrui; Wei, Chunjing; Chu, Hang; Chen, Yaping

    2016-09-01

    The Xing'an-Inner Mongolia Orogenic Belt (XIMOB) exposed in the eastern section of the Central Asian Orogenic Belt (CAOB) is generally thought to have resulted from closure of the Paleo-Asian Ocean. However, disputations still exist on the age and detailed tectonic processes involved in its final amalgamation. The Solonker suture zone in the central Inner Mongolia, once recognized as the major paleo-plate boundary recording the terminal collision of the XIMOB, is characterized by extensive regional low-temperature metamorphism of greenschist to epidote-amphibolite facies with local presence of blueschists, which lacks systematic study. Four metabasite and garnet-mica schist samples were studied for determination of metamorphic P-T evolution using pseudosection and conventional thermobarometry. The two metabasite samples from Wulangou and Daqing Pasture contain actinolite, albite, epidote, chlorite and hornblende (in Daqing Pasture) and are estimated to have peak P-T conditions of 5.2-5.9 kbar/415-450 °C in Wulangou and 7.0-7.9 kbar/470-475 °C in Daqing Pasture. Two garnet-mica schist samples from Shuangjing (or Shuangjing schist) contain garnet porphyroblasts, muscovite, quartz, plagioclase, chlorite with or without potassium feldspar, biotite, and calcite, and are modeled to record prograde P-T vectors respectively of 3.0 kbar/482 °C-3.3 kbar/495 °C and 4.2 kbar/478 °C-4.8 kbar/483 °C, followed by near-isothermal decompression. The zircon U-Pb dating analyses suggest that the metamorphism probably occurred soon afterwards in the Early Mesozoic. The peak P-T conditions for the metabasite and garnet-mica schist samples yield thermal gradients respectively of 18-22 °C/km and 26-33 °C/km, being intermediate and low P/T series, and the metamorphic evolution in these rocks characteristic of clockwise P-T paths may correspond to tectonic thickening and thinning processes. The extensive low-temperature metamorphism of intermediate to low P/T types along the

  5. Mass transfer and trace element redistribution during hydration of granulites in the Bergen Arcs, Norway.

    Science.gov (United States)

    Centrella, Stephen; Austrheim, Håkon; Putnis, Andrew

    2016-04-01

    The Bergen Arcs located on the Western coast of Norway are characterized by Precambrian granulite facies rocks partially hydrated at amphibolite and eclogite facies conditions. Over an area of ca. 1000 km², relict of granulite facies lenses make up only ca. 10% of the observed outcrops. At Hilland Radöy, granulite displays sharp hydration fronts across which the granulite facies assemblage composed of garnet (55%) and clinopyroxene (45%) is replaced by an amphibolite facies mineralogy defined by chlorite, epidote and amphibole. The major element bulk composition does not change significantly across the hydration front, apart from the volatile components (loss on ignition, LOI) that increases from 0.17 wt.% in the granulite to 2.43 wt.% in the amphibolite (Centrella et al., 2015). The replacements of garnet and clinopyroxene are pseudomorphic indicating a perfect preservation of the parent crystal shape. The textural evolution during the replacement is consistent with the coupled dissolution-precipitation mechanism where garnet is replaced by chlorite, epidote and pargasite and clinopyroxene by hornblende and quartz. Based on the observations of an isovolumetric replacement, the mass loss during hydration was estimated at 13%. This study is based on the trace element redistribution during the hydration using the same samples as Centrella et al. (2015). The local mass transfer during the replacement process determined from the major element is also confirmed by the trace element redistribution. The LILE, HFSE and REE losses and gains in replacing the garnet are approximately balanced by the opposite gains and losses associated with the replacement of clinopyroxene. Because the hydration involves reduction of rock density, the volume preservation (isovolumetric reaction), together with the mass balance calculations, requires a significant loss of the mass of the rock to the fluid phase: 13% based on the major element redistribution and around 20% based on the REE

  6. Provenance and composition of unusually chrome and nickel-rich bucket-shaped pottery from Rogaland (southwestern Norway)

    Science.gov (United States)

    Zimmermann, Udo; Kristoffersen, Elna Siv; Fredriksen, Per Ditlef; Bertolino, Silvana A. R.; Andò, Sergio; Bersani, Danilo

    2016-05-01

    We report results from FE-SEM-EDS, geochemical, mineralogical analyses and Raman spectroscopy of pottery of bucket-shaped ceramic from Rogaland (southwestern Norway) dated between the 5th and 6th Century. The study reveals a very rare pottery composition including asbestos-group minerals and an unusual enrichment in compatible elements like Cr (8-27 × Post Archean average shale (PAS), McLennan et al., 2006), Ni (2-8 × normal shale) and Co (2-3 × PAS). X-Rray diffraction and Raman spectroscopy could pinpoint that Ni is introduced by specific Ni-rich talc mineral and chlorite minerals and Cr occurs in a rare Cr-rich talc, and possibly in a Cr-chlorite, these minerals are the most abundant in the pottery, which is supported by strong enrichment in Mg (10-20 × PAS). The addition of Mg, Cr, Ni and Co and other compatible trace elements is to our current knowledge not caused by anthropogenic activity but related to the used materials, which are alteration products of mafic and ultramafic rocks or genetically related to mafic and ultramafic rocks. Rocks of this type are exposed in vicinity of the sampling areas in a region called Karmøy, hosting a world famous ophiolite complex, which is identified as the major source for the mafic and ultramafic component, as the next succession of a similar composition is far further north located in Norway and a number of rock types on Karmøy matches the chemical composition of the pottery. The here reported composition is spectacular and extremely rare - if ever found - in pottery. Our study shows that unusual material sources have been used in pottery production, and this opens for discussion whether the materials were deliberately selected by the manufacturers, thereby expressing a specific social function, in a time period where more functional clay types and additives, and certainly functional and sufficient for use in pottery, where abundant in areas of Rogaland closer to where the pots were found.

  7. From chemical mapping to pressure temperature deformation micro-cartography: mineralogical evolution and mass transport in thermo-mechanic disequilibrium systems: application to meta-pelites and confinement nuclear waste materials; De l'imagerie chimique a la micro-cartographie Pression-Temperature-Deformation: evolution mineralogique et transport de matiere dans des systemes en desequilibre thermomecanique. Applications aux metapelites et aux materiaux de stockage de dechets radioactifs

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, V. de

    2006-03-15

    The mineralogical composition of metamorphic rocks or industrial materials evolves when they are submitted to thermomechanical disequilibria, i.e. a spatial or temporal pressure and temperature evolution, or chemical disequilibria as variations in redox conditions, pH... For example, during low temperature metamorphic processes, rocks re-equilibrate only partially, and thus record locally thermodynamic equilibria increasing so the spatial chemical heterogeneities. Understanding the P-T evolution of such systems and deciphering modalities of their mineralogical transformation imply to recognize and characterize the size of these local 'paleo-equilibria', and so to have a spatial chemical information at least in 2 dimensions. In order to get this information, microprobe X-ray fluorescence maps have been used. Computer codes have been developed with Matlab to quantify these maps in view of thermo-barometric estimations. In this way, P-T maps of mineral crystallisation were produced using the multi-equilibria thermodynamic technique. Applications on two meta-pelites from the Sambagawa blue-schist belt (Japan) and from the Caledonian eclogitic zone in Spitsbergen, show that quantitative chemical maps are a powerful tool to retrieve the metamorphic history of rocks. From these chemical maps have been derived maps of P-T-time-redox-deformation that allow to characterize P-T conditions of minerals formation, and so, the P-T path of the sample, the oxidation state of iron in the chlorite phase. As a result, we underline the relation between deformation and crystallisation, and propose a relative chronology of minerals crystallisation and deformations. The Fe{sup 3+} content map in chlorite calculated by thermodynamic has also been validated by a {mu}-XANES mapping at the iron K-edge measured at the ESRF (ID24) using an innovative method. Another application relates to an experimental study of clay materials, main components of an analogical model of a nuclear

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-15

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

  9. Coupled mass transfer through a fluid phase and volume preservation during the hydration of granulite: An example from the Bergen Arcs, Norway

    Science.gov (United States)

    Centrella, Stephen; Austrheim, Håkon; Putnis, Andrew

    2015-11-01

    The Precambrian granulite facies rocks of Lindås Nappe, Bergen Arcs, Caledonides of W. Norway are partially hydrated at amphibolite and eclogite facies conditions. The Lindås Nappe outcrops over an area of ca. 1000 km2 where relict granulite facies lenses make up only ca. 10%. At Hillandsvatnet, garnetite displays sharp hydration fronts across which the granulite facies assemblage composed of garnet (55%) and clinopyroxene (45%) is replaced by an amphibolite facies mineralogy defined by chlorite, epidote and amphibole. The major element bulk composition does not change significantly across the hydration front, apart from the volatile components (loss on ignition, LOI) that increases from 0.17 wt.% in the granulite to 2.43 wt.% in the amphibolite. However the replacements of garnet and of clinopyroxene are pseudomorphic so that the grain shapes of the garnet and clinopyroxene are preserved even when they are completely replaced. The textural evolution during the replacement of garnet by pargasite, epidote and chlorite and of pyroxene by hornblende and quartz in our rock sample conforms to that expected by a coupled dissolution-precipitation mechanism. SEM and electron microprobe analysis coupled with the software XMapTools V 1.06.1 were used to quantify the local mass transfer required during the replacement processes. The element losses and gains in replacing the garnet are approximately balanced by the opposite gains and losses associated with the replacement of clinopyroxene. The coupling between dissolution and precipitation on both the grain and whole rock spatial scale preserves the volume of the rock throughout the hydration process. However, the hydration involves reduction of rock density and mass balance calculations, together with volume preservation (isovolumetric reaction) require a significant loss of the mass of the rock to the fluid phase. This suggests a mechanism for coupling between the local stress generated by hydration reactions and mass

  10. Source and evolution of ore-forming hydrothermal fluids in the northern Iberian Pyrite Belt massive sulphide deposits (SW Spain): evidence from fluid inclusions and stable isotopes

    Science.gov (United States)

    Sánchez-España, Javier; Velasco, Francisco; Boyce, Adrian J.; Fallick, Anthony E.

    2003-08-01

    A fluid inclusion and stable isotopic study has been undertaken on some massive sulphide deposits (Aguas Teñidas Este, Concepción, San Miguel, San Telmo and Cueva de la Mora) located in the northern Iberian Pyrite Belt. The isotopic analyses were mainly performed on quartz, chlorite, carbonate and whole rock samples from the stockworks and altered footwall zones of the deposits, and also on some fluid inclusion waters. Homogenization temperatures of fluid inclusions in quartz mostly range from 120 to 280 °C. Salinity of most fluid inclusions ranges from 2 to 14 wt% NaCl equiv. A few cases with Th=80-110 °C and salinity of 16-24 wt% NaCl equiv., have been also recognized. In addition, fluid inclusions from the Soloviejo Mn-Fe-jaspers (160-190 °C and ≈6 wt% NaCl equiv.) and some Late to Post-Hercynian quartz veins (130-270 °C and ≈4 wt% NaCl equiv.) were also studied. Isotopic results indicate that fluids in equilibrium with measured quartz (δ18Ofluid ≈-2 to 4‰), chlorites (δ18Ofluid ≈8-14‰, δDfluid ≈-45 to -27‰), whole rocks (δ18Ofluid ≈4-7‰, δDfluid ≈-15 to -10‰), and carbonates (δ18Oankerite ≈14.5-16‰, δ13Cfluid =-11 to -5‰) evolved isotopically during the lifetime of the hydrothermal systems, following a waxing/waning cycle at different temperatures and water/rock ratios. The results (fluid inclusions, δ18O, δD and δ13C values) point to a highly evolved seawater, along with a variable (but significant) contribution of other fluid reservoirs such as magmatic and/or deep metamorphic waters, as the most probable sources for the ore-forming fluids. These fluids interacted with the underlying volcanic and sedimentary rocks during convective circulation through the upper crust.

  11. Fault-zone structure and weakening processes in basin-scale reverse faults: The Moonlight Fault Zone, South Island, New Zealand

    Science.gov (United States)

    Alder, S.; Smith, S. A. F.; Scott, J. M.

    2016-10-01

    The >200 km long Moonlight Fault Zone (MFZ) in southern New Zealand was an Oligocene basin-bounding normal fault zone that reactivated in the Miocene as a high-angle reverse fault (present dip angle 65°-75°). Regional exhumation in the last c. 5 Ma has resulted in deep exposures of the MFZ that present an opportunity to study the structure and deformation processes that were active in a basin-scale reverse fault at basement depths. Syn-rift sediments are preserved only as thin fault-bound slivers. The hanging wall and footwall of the MFZ are mainly greenschist facies quartzofeldspathic schists that have a steeply-dipping (55°-75°) foliation subparallel to the main fault trace. In more fissile lithologies (e.g. greyschists), hanging-wall deformation occurred by the development of foliation-parallel breccia layers up to a few centimetres thick. Greyschists in the footwall deformed mainly by folding and formation of tabular, foliation-parallel breccias up to 1 m wide. Where the hanging-wall contains more competent lithologies (e.g. greenschist facies metabasite) it is laced with networks of pseudotachylyte that formed parallel to the host rock foliation in a damage zone extending up to 500 m from the main fault trace. The fault core contains an up to 20 m thick sequence of breccias, cataclasites and foliated cataclasites preserving evidence for the progressive development of interconnected networks of (partly authigenic) chlorite and muscovite. Deformation in the fault core occurred by cataclasis of quartz and albite, frictional sliding of chlorite and muscovite grains, and dissolution-precipitation. Combined with published friction and permeability data, our observations suggest that: 1) host rock lithology and anisotropy were the primary controls on the structure of the MFZ at basement depths and 2) high-angle reverse slip was facilitated by the low frictional strength of fault core materials. Restriction of pseudotachylyte networks to the hanging-wall of the

  12. Thermal metamorphism of mantle chromites and the stability of noble-metal nanoparticles

    Science.gov (United States)

    González-Jiménez, José M.; Reich, Martin; Camprubí, Antoni; Gervilla, Fernando; Griffin, William L.; Colás, Vanessa; O'Reilly, Suzanne Y.; Proenza, Joaquín A.; Pearson, Norman J.; Centeno-García, Elena

    2015-08-01

    The Loma Baya complex in south-western Mexico is a volume of chromitite-bearing oceanic mantle that records a complex metamorphic history, defined by a first stage of hydrous metamorphism overprinted by a short-lived thermal event associated with an Eocene granite intrusion. During the hydrous metamorphism, the primary magmatic chromite-olivine assemblage was replaced by a secondary, porous intergrowth of Fe2+-rich chromite and chlorite. The heat supplied by an Eocene-age granite intrusion reversed the hydration reaction, producing chromite rims with perfectly developed crystal faces. This third-generation chromite is in equilibrium with highly magnesian (neoformed) olivine and defines a chemical trend analogous to the original magmatic one. The preservation of both reactions in the Loma Baya chromitite provides compelling evidence that the hydration of chromite can be reversed by either prograde metamorphism or any heating event, confirming previous thermodynamic predictions. Understanding these complex features is of particular interest due to the fact that changes in temperature and variable degrees of fluid/rock interaction during metamorphism and intrusion have also significantly affected the chromite-hosted IPGE carrier phases. Here, we propose that the metamorphic fluids involved in the hydrous metamorphism have caused the desulphurization of laurite RuS2, releasing minute particles of Ru-Os-Ir alloys phenomena in natural systems, shedding new light on the kinetic controls of nano- to micron-scale IPGE particle distributions during metamorphism.

  13. 中低温热液近矿围岩蚀变的地球化学模型(以某矿区为例)

    Institute of Scientific and Technical Information of China (English)

    王联魁

    1977-01-01

    Detailed geological studies and systematic examinations in terms of petrology,petrochemistry, mineralogy and minor clement distribution with respect to a number of typical profiles together with some available experimental data, have improved our understanding of the general regularity regarding meso- and epi-hydrothermalal terations of Si-, Al-, K-, Na- rich wallrocks as is referred to as the “geochemical model of alteration evolution” in this paper. General trend and broad similarities are recognizable in the process of hydrothermal alterations. It is clear that the continued variation in ionic eoncentration of hydrothermal solutions act as the fundamental control determining the development of alteration. As a resuit, differentiation and evolution of the hydrothermal solutions have taken place in response to this variation from the inner parts outwards as well as from the lower parts upwards. Temporally, mineralization is to a first approximation contemporancous with, or somewhat later than, alteration. Spatially, it is reflected by the zonal arrangement of alterations in the following sequence: silicification,petnssie alterations(♀),illitization(or sericitization),montmorilloitization,kaolinization,chloritization-albitization(or propylitization),and etc.Preliminary attempts have been made to apply this“model”to iron and ecpper depositions.

  14. Minerals from the Pohorje igneous massif

    Directory of Open Access Journals (Sweden)

    Nina Zupančič

    1995-12-01

    Full Text Available The mineralogical composition of Pohorje igneous rocks was determined by means of optical microscopy and X-ray poviwder diffraction. Quartz, plagioclases and K-feldspars are the major minerals in the granodiorite and its porphyritic varieties. Characteristic and accessory minerals are biotite, hornblende, apatite, orthite, epidote, zircon and opaque minerals. Muscovite, pyroxenes and garnets occur rarely. The major minerals in malchites are plagioclases and hornblende.Restitic crystals of plagioclases, apatite and zircon were present in magma from which the Pohorje igneous body solidified. Sulphides, apatite and zircon precipitated in the first stage of magma crystallisation. In the next stage orthite, epidote and sphene crystallized. Biotite crystals probably formed slightly beforehornblende. The precipitation continued with plagioclases, quartz of first generation, more acid plagioclases, biotite and quartz of second generation. The crystallisation sequence ended with K-feldspar that replaced other minerals.The primary minerals are somewhere autometamorphosed to chlorite, epidote, calcite, sphene, sericite, kaolinite and limonite. In some areas in the NW part of Pohorje igneous body the alteration was hydrothermal.

  15. Zinc-rich clays in supergene non-sulfide zinc deposits

    Science.gov (United States)

    Choulet, F.; Buatier, M.; Barbanson, L.; Guégan, R.; Ennaciri, A.

    2016-04-01

    The nature and the origin of zinc clays are poorly understood. With the example of the Bou Arhous Zn-Pb ore deposit in the Moroccan High Atlas, this study presents new data for the mineralogical and chemical characterization of barren and zinc clays associated with non-sulfide zinc ores. In the field, white to ocher granular clays are associated with willemite (Zn2SiO4), while red clays fill karst-related cavities cutting across the non-sulfide ore bodies. Red clays (kaolinite, chlorite, illite, and smectite) present evidence of stratification that reflects internal sedimentation processes during the karst evolution. White clays contain 7-Å clay mineral/smectite irregular interstratified minerals with less than 20 % of smectite layers. Willemite is partially dissolved and is surrounded by authigenic zinc clay minerals. Together with XRD results, WDS analyses on newly formed clay aggregates suggest that this interstratified mineral is composed of fraipontite and sauconite. CEC measurements support that zinc is only located within the octahedral sheets. These new results support the following process: (i) dissolution of willemite, leading to release of Si and Zn, (ii) interaction between Zn-Si-rich solutions and residual-detrital clays, and (iii) dissolution of kaolinite and formation of interstratified zinc clay minerals that grew over detrital micas.

  16. Differential effects on innate versus adaptive immune responses by WF10.

    Science.gov (United States)

    Giese, Thomas; McGrath, Michael S; Stumm, Susanne; Schempp, Harald; Elstner, Erich; Meuer, Stefan C

    2004-06-01

    Oxidative compounds that are physiologically generated in vivo can induce natural defense mechanisms to enhance the elimination of pathogens and to limit inflammatory tissue damage in the course of inflammation. Here, we have investigated WF10, a chlorite-based non-toxic compound for its functional activities on human PBMC in vitro. WF10 exerts potent immune-modulatory effects through generating endogenous oxidative compounds such as taurine chloramine. Proliferation and IL-2 production of anti-CD3 stimulated PBMC were inhibited by WF10, as was the nuclear translocation of the transcription factor NFATc. In PBMC and monocytes, however, WF10 induced pro-inflammatory cytokines like IL-1beta, IL-8, and TNF-alpha. In the monocytic cell line THP-1, the activation of the transcription factors AP-1 and NFkappaB by WF10 was demonstrated. Inhibition of NFAT regulated genes in activated lymphocytes in concert with the induction of several myeloid cell associated pro-inflammatory genes in monocytes represents a novel mechanism of immune modulation.

  17. Texture and anisotropy analysis of Qusaiba shales

    KAUST Repository

    Kanitpanyacharoen, Waruntorn

    2011-02-17

    Scanning and transmission electron microscopy, synchrotron X-ray diffraction, microtomography and ultrasonic velocity measurements were used to characterize microstructures and anisotropy of three deeply buried Qusaiba shales from the Rub\\'al-Khali basin, Saudi Arabia. Kaolinite, illite-smectite, illite-mica and chlorite show strong preferred orientation with (001) pole figure maxima perpendicular to the bedding plane ranging from 2.4-6.8 multiples of a random distribution (m.r.d.). Quartz, feldspars and pyrite crystals have a random orientation distribution. Elastic properties of the polyphase aggregate are calculated by averaging the single crystal elastic properties over the orientation distribution, assuming a nonporous material. The average calculated bulk P-wave velocities are 6.2 km/s (maximum) and 5.5 km/s (minimum), resulting in a P-wave anisotropy of 12%. The calculated velocities are compared with those determined from ultrasonic velocity measurements on a similar sample. In the ultrasonic experiment, which measures the effects of the shale matrix as well as the effects of porosity, velocities are smaller (P-wave maximum 5.3 km/s and minimum 4.1 km/s). The difference between calculated and measured velocities is attributed to the effects of anisotropic pore structure and to microfractures present in the sample, which have not been taken into account in the matrix averaging. © 2011 European Association of Geoscientists & Engineers.

  18. A simple method to model the reduced environment of lake bottom sapropel formation

    Science.gov (United States)

    Gaskova, Olga L.; Strakhovenko, Vera D.; Ermolaeva, Nadezhda I.; Zarubina, Eugene Yu.; Ovdina, Ekaterina A.

    2016-07-01

    The Kambala and Barchin brackish lakes (Baraba steppe, southern West Siberia) contain an organic-rich sapropel layer that was formed in oxygen-depleted waters. We measured the bulk sediment elemental composition, the water chemistry and determined the mineralogical composition and predominant biota species (Diatoms and Cyanobacteria in phytoplankton community respectively) in the lakes. The result indicates that the first lake has a siliceous type of sapropel and the second a carbonaceous one. A computer thermodynamic model was developed for chemical interaction in water-bottom sediment systems of the Kambala and Barchin Lakes. The surface sodium bicarbonate waters are supersaturated with respect to calcite, magnesite (or low Mg-calcite), quartz and chlorite with minor strontianite, apatite and goethite (pH 8.9-9.3, Eh 0.3 V). Nevertheless, it is shown that during sapropel deposition, deep silt waters should be anoxic (Ehimpact and abiotic reduction. Thermodynamic calculation has shown that silt water is not necessarily euxinic (anoxic and sulfidic). Depending on Eh, sulfate sulfur can dominate in solution, causing the formation of gypsum together with pyrite. An attempt was made to find a reason for solution supersaturation with respect to Ca and Mg ions due to their complexation with humic acids.

  19. Pattern formation in a (2 + 1)-species activator-inhibitor-immobilizer system

    Science.gov (United States)

    Pearson, John E.

    1992-09-01

    The necessary and sufficient conditions for a Turing instability in a (2 + 1)-component reaction-diffusion system are derived. The 2-component subsystem consists of an arbitrary activator-inhibitor system in which the activator and the inhibitor diffuse at identical rates. The activator reacts with an immobile substrate to form an immobile complex which does not diffuse. It is found that the critical wavenumber and the location of the instability in parameter space are independent of the initial substrate concentration. As a special case, the (2 + 1)-variable activator-inhibitor-immobilizer system can be reduced to an activator-inhibitor system in which the activator diffuses more slowly than the inhibitor. This occurs when the time scales in the system satisfy certain constraints. The general results are applied to a (2 + 1)-variable model of the chlorite-iodide-starch reaction recently proposed by Epstein and Lengyel to explain the experimental observation of Turing patterns in a related system. I find an intrinsic wavelength which is within a factor of two of the experimentally observed wavelength, but the necessary conditions for the (2 + 1)-variable system to reduce to a two-variable activator-inhibitor system with rescaled diffusion coefficients are not satisfied.

  20. Microcrack technology. Progress report, 1 April 1979-29 February 1980

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, G.; Caruso, L.; Padovani, E.

    1980-03-01

    Microcracks in samples of core from a 3000-foot hole in the Conway granite, near North Conway, New Hampshire, are abundant and most of them are sealed with siderite, chlorite, quartz, hematite, clay, or microbreccia. The sealed cracks are 1 to 100..mu.. wide, intersect many grain boundaries, often coincide with grain boundaries, and both intersect and contain minerals that are normally rich in U and Th. The abundances of U and Th in 100-gm-bulk samples range from 0.1 to 30 ppM and from 6 to 100 ppM, respectively. The working hypothesis that U and Th have migrated through the microcracks in CO/sub 2/-rich waters is proposed. In the Redstone Quarry core, the presently open microcracks are preferentially oriented; most open cracks have horizontal surfaces. Samples of Devonian shales have been obtained for the purpose of examining microcracks in relation to the production of natural gas. The problems of sample preparation for fissile shale have been largely solved. Samples from the NTS have been prepared for the examination of microcracks in relation to possible disposal sites for radioactive waste.

  1. REASSESSMENT OF THE VOLKONSKOITE-CHROMIAN SMECTITE NOMENCLATURE PROBLEM.

    Science.gov (United States)

    Foord, Eugene E.; Starkey, Harry C.; Taggart, Joseph E.; Shawe, Daniel R.

    1987-01-01

    The name volkonskoite was first used in 1830 to describe a bright blue-green, chromium-bearing clay material from the Okhansk region, west of the Ural Mountains, U. S. S. R. Since that time, the name has been applied to numerous members of the smectite group of clay minerals, although the reported chromium content has ranged from 1% to about 30% Cr//2O//3. The name has also been applied to some chromian chlorites. Because volkonskoite has been used for materials that differ not only in their chromium content but also in their basic structure, the species status of mineral has been unclear. To resolve this uncertainty, two specimens of volkonskoite from (1) Mount Efimiatsk, the type locality in the Soviet Union (USNM 16308) and (2) the Okhansk region in the Perm Basin, U. S. S. R. , (USNM R4820), were examined by several mineralogical techniques. Structural formulas for the two types of samples are given. On the basis of the data presented, volkonskoite appears to be a dioctahedral member of the smectite group that contains chromium as the dominant cation in the octahedral layer. Smectites containing less than this amount of octahedral chromium should not be called volkonskoite.

  2. Metasomatic uranium mineralisation of the Mount Isa North Block

    International Nuclear Information System (INIS)

    Proterozoic uranium deposits of the Mt Isa North Block are centred 40 km north of Mt Isa, NW Queensland. Regionally, the deposits occur within the Leichhardt River Fault Trough of the Mt Isa Inlier. Uranium mineralisation is likely related to the 1 600-1 500 Ma Isan Orogeny. Structurally-controlled uranium mineralisation is preferentially hosted in greenschist facies basalts and interbedded clastic sediments of the Eastern Creek Volcanics (ECV). Uranium deposits of the Mt Isa North Block are defined by the following general characteristics: • Pervasive sodium and calcium metasomatism, expressed as red albitite with finely disseminated hematite and calcite, with distal zones of chlorite and magnetite. • Uraniferous albitite deposits typically comprise en echelon lenses and shoots. • Mineralisation is developed along N- to NE-striking shear zones with associated brittle deformation of the host lithologies. • Host rocks are mostly basalt flows with flow-top breccias and interbedded sandstones and siltstones of the ECV; quartzites are also locally mineralised. • Uranium mineralogy of albitites comprises brannerite, coffinite, uraninite and uraniferous zircon. The Mt Isa North Blocks includes 11 tenements being explored for uranium by Summit Resources. Summit’s five uranium resources total 95.7 Mlb U3O8. Summit is in a 50/50 Joint Venture with Paladin on the Valhalla and Skal deposits. Paladin also has a direct ownership of 81.99% of the issued shares of Summit Resources. (author)

  3. Chondrule Glass Alteration in Type IIA Chondrules in the CR2 Chondrites EET 87770 and EET 92105: Insights into Elemental Exchange Between Chondrules and Matrices

    Science.gov (United States)

    Burger, Paul V.; Brearley, Adrian J.

    2004-01-01

    CR2 carbonaceous chondrites are a primitive group of meteorites that preserve evidence of a variety of processes that occurred in the solar nebula as well as on asteroidal parent bodies. CR2 chondrites are distinct from other carbonaceous chondrites by (among other properties) their relatively high abundance of chondrules (50-60 vol. %) and Fe,Ni metal (5-8 vol. %) [1]. Like the CM2 chondrites, the CRs have been affected by aqueous alteration and according to [2] show a range of degrees of alteration. In weakly- altered CR chondrites, fine-grained matrices and chondrule rims have been partially altered and chondrule mesostases show evidence of incipient aqueous alteration. In these meteorites, glassy mesostasis is still common. However, some CR chondrites, (e.g. Renazzo and Al Rais) show evidence of much more extensive alteration with complete replacement of chondrule mesostasis [2] by chlorite and serpentine. Although the general characteristics of alteration of the CR chondrites have been described, the details of alteration reactions in these meteorites remain unclear. In addition, the setting for aqueous alteration is poorly understood: both asteroidal and preaccretionary alteration scenarios have been proposed [2].

  4. Comparative study of different surface decontaminants on chicken quality.

    Science.gov (United States)

    Sinhamahapatra, M; Biswas, S; Das, A K; Bhattacharyya, D

    2004-10-01

    (1) A comparative study on the effect of different surface decontaminants: hot water at 70 degrees C for one minute; 2% lactic acid for 30 s; 1200 p.p.m. acidified sodium chlorite (ASC) solution for 5 s and 50 p.p.m. chlorine solution for 5 min in the form of dips and sprays on the surface of dressed broilers for 0, 24 and 48 h of storage was conducted. (2) The variables studied were, total plate count (TPC), presumptive coliform count (PCC), pH and extract release volume (ERV). All treatments reduced TPC and PCC. (3) Lactic acid dip and hot water dip were the most effective for reducing TPC (1.36 and 1.28 log/cm2, respectively) with no significant difference between them. (4) ASC and hot water in dip could diminish PCC (1.37 and 1.34 log/cm2, respectively) and did not vary significantly. (5) No treatment affected muscle pH, water holding capacity (WHC), ERV, appearance, smell, tenderness and overall acceptability of treated broilers significantly. (6) Hot water treatment is the cheapest, most convenient and simplest decontamination technique for hygienic and wholesome poultry production. PMID:15623215

  5. Mechanical and mineralogical modifications of petrophysical parameters by deformation bands in a hydrocarbon reservoir (Matzen, Austria)

    Science.gov (United States)

    Kaiser, Jasmin; Exner, Ulrike; Gier, Susanne; Hujer, Wolfgang

    2010-05-01

    In porous sedimentary rocks, fault zones are frequently accompanied by deformation bands. These structures are tabular zones of displacement, where grain rotation and in some cases grain fracturing result in a significant reduction in porosity. Core samples were analyzed close to large normal faults from the most productive hydrocarbon reservoir in the Vienna Basin (Austria), the Matzen oil field. The Badenian terrigeneous sandstones contain predominately quartz, feldspar and dolomite as sub-rounded, detrial grains and are weakly cemented by chlorite and kaolinite. Deformation bands occur as single bands of ca. 1-3 mm thickness and negligible displacement, as well as strands of several bands with up to 2 cm thickness and displacement of 1-2 cm. A dramatic porosity reduction can already be recognized macroscopically. In some samples, the corresponding reduction in permeability is highlighted by different degree of oil staining on either side of the bands. The mineralogical composition of the deformation bands compared to the host rock does not indicate any preferential cementation or diagenetic growth of clay minerals or calcite. Instead, clay minerals are slightly enriched in the host sediment. These observations suggest that the formation of deformation bands predates the cementation in the Matzen sands. Thus, we speculate that the porosity reduction is predominately caused by cataclastic grain size reduction. Identification of the grain scale processes of porosity and permeability reduction, in combination with the analysis of the spatial distribution and orientation of the deformation bands may provide valuable information on the reservoir properties and fluid migration paths.

  6. Uraniferous mineralizations in the Kuusamo Schist Belt, northeastern Finland

    International Nuclear Information System (INIS)

    The Kouveraara Co-Cu-Au mineralization was found in 1982 with the aid of a geophysical ground survey. This survey was connected with research on the Kouvervaara uranium mineralization in the Early Proterozoic Kuusamo Schist Belt, located just south of the Arctic Circle. In further work, using the Kouvervaara sulphide mineralization as a reference, six Co and Au bearing sulphide mineralizations were discovered, with the help of low altitude aerial geophysical techniques. The Co-Au mineralizations, hosted by the Sericite Quartzite Formation, occur within the hydrothermally altered zones. These zones consist of chloritization, carbonatization, sulphidization, sericitization and albitization, the latter being the most extensive. Excluding the Juomasuo mineralization, uranium is only a trace element in these mineralizations. Other characteristic trace elements are molybdenum and tungsten. The Sivakkaharju and Konttiaho Co-Au-U-Mo mineralizations were found by radiometric ground surveys carried out in 1985 and 1986. These hydrothermal mineralizations occur within brecciated quartz-albite-carbonate rocks and are good manifestations of the positive correlation between uranium and gold in the Kuusamo area. Compared with the other sulphide mineralizations, the Au, U, and Mo contents are remarkably high. Genetically, the mineralizations in the Kuusamo area are associated with deep seated fracture and fault zones, controlled by ancient intracontinental hot spot activity and continental rifting. (author). 31 refs, 6 figs, 2 tabs

  7. Determination of the mineral stability field of evolving groundwater in the Lake Bosumtwi impact crater and surrounding areas

    Science.gov (United States)

    Loh, Yvonne Sena Akosua; Yidana, Sandow Mark; Banoeng-Yakubo, Bruce; Sakyi, Patrick Asamoah; Addai, Millicent Obeng; Asiedu, Daniel Kwadwo

    2016-09-01

    Conventional graphical techniques, mass balance geochemical modelling, and multivariate statistical methods were jointly applied to hydrogeochemical data of groundwater from the fractured rock aquifer system, and surface water in the Bosumtwi and surrounding areas to reveal evolutionary trends and the characteristics of evolving groundwater in the area. Four clusters distinguished from the Q-mode hierarchical cluster analysis (HCA) comprised three main groundwater associations and one surface water group (lake water). Although both water resources are of low mineralization (TDS < 1000 mg/l), it was observed that the groundwater from the upper catchment with hydrochemical facies dominated by Nasbnd Mgsbnd HCO3-, evolves to Casbnd Mgsbnd and mixed cations HCO3- water types at the lower reaches. The lake water on the other hand is Nasbnd HCO3- water type. Results from principal component analyses (PCA) and other geochemical interpretations distinguished three sources of variations in the hydrochemistry. Saturation indices of possible reactive mineral phases show groundwater undersaturation relative to albite, anorthite, aragonite, barite, calcite, chlorite, chrysotile, dolomite, gypsum, k-felspar and talc, and supersaturation with respect to gibbsite, kaolinite, Ca-montmorillonite and k-mica in the area. The PCA and other geochemical interpretation identify weathering of feldspars and carbonate mineral dissolution as predominantly influencing the hydrochemistry of the groundwater. Hydrolysis of the aluminosilicates causes the groundwater to reach equilibrium with kaolinite. In addition to dissolution of silicates, the chemical composition of the lake water has been influenced by evaporation and consequent carbonate saturation.

  8. High-strength nanocellulose-talc hybrid barrier films.

    Science.gov (United States)

    Liimatainen, Henrikki; Ezekiel, Ngesa; Sliz, Rafal; Ohenoja, Katja; Sirviö, Juho Antti; Berglund, Lars; Hormi, Osmo; Niinimäki, Jouko

    2013-12-26

    Hybrid organic-inorganic films mimicking natural nacre-like composite structures were fabricated from cellulose nanofibers obtained from sequential periodate-chlorite oxidation treatment and talc platelets, using a simple vacuum-filtration method. As a pretreatment, commercial talc aggregates were individualized into well-dispersed talc platelets using a wet stirred media mill with high-shear conditions to promote the homogeneity and mechanical characteristics of hybrids. The nanofiber-talc hybrids, which had talc contents from 1 to 50 wt %, were all flexible in bending, and possessed tensile strength and Young's modulus values up to 211 ± 3 MPa and 12 ± 1 GPa, respectively, the values being remarkably higher than those reported previously for nanofibrillated cellulose-talc films. Because of the lamellar and well-organized structure of hybrids in which the talc platelets were evenly embedded, they possessed a small pore size and good oxygen barrier properties, as indicated by the preliminary results. The talc platelets decreased the moisture adsorption of highly talc-loaded hybrids, although they still exhibited hydrophilic surface characteristics in terms of contact angles. PMID:24215630

  9. Strong, self-standing oxygen barrier films from nanocelluloses modified with regioselective oxidative treatments.

    Science.gov (United States)

    Sirviö, Juho Antti; Kolehmainen, Aleksi; Visanko, Miikka; Liimatainen, Henrikki; Niinimäki, Jouko; Hormi, Osmo E O

    2014-08-27

    In this work, three self-standing nanocellulose films were produced from birch pulp using regioselective oxidation and further derivatization treatments. The modified celluloses were synthesized using periodate oxidation, followed by chlorite oxidation, bisulfite addition, or reductive amination with amino acid taurine, which resulted in dicarboxylic acid cellulose (DCC), α-hydroxy sulfonic acid cellulose (HSAC), and taurine-modified cellulose (TC), respectively. The nanocelluloses were fabricated by mechanical disintegration using high-pressure homogenization. Mechanical and barrier properties of the nanocellulose films were characterized. Two (2,2,6,6-tetramethyl-piperidin-1-yl)oxyl (TEMPO) oxidation-based nanocellulose films were also produced, and their properties were compared to the periodate-based nanocellulose films. All of the periodate-based nanocellulose films showed high tensile strength (130-163 MPa) and modulus (19-22 GPa). Oxygen barrier properties of the films were superior to many synthetic and composite materials; in particular, the nanofibrillated DCC films had oxygen permeability as low as 0.12 cm(3) μm/(m(2) d kPa) at 50% relative humidity. Compared to films of TEMPO-oxidized nanocelluloses, all of the periodate-based nanocellulose films had similar or even better mechanical and barrier properties, demonstrating versatility of periodate oxidation to obtain nanocellulose films with adjustable properties. Also, for the first time, amino-acid-based cellulose modification was used in the production of nanocellulose. PMID:25089516

  10. Genetic relationships between skarn ore deposits and magmatic activity in the Ahar region, Western Alborz, NW Iran

    Directory of Open Access Journals (Sweden)

    Mollai Habib

    2014-06-01

    Full Text Available Paleocene to Oligocene tectonic processes in northwest Iran resulted in extensive I-type calc-alkaline and alkaline magmatic activity in the Ahar region. Numerous skarn deposits formed in the contact between Upper Cretaceous impure carbonate rocks and Oligocene-Miocene plutonic rocks. This study presents new field observations of skarns in the western Alborz range and is based on geochemistry of igneous rocks, mineralogy of the important skarn deposits, and electron microprobe analyses of skarn minerals. These data are used to interpret the metasomatism during sequential skarn formation and the geotectonic setting of the skarn ore deposit related igneous rocks. The skarns were classified into exoskarn, endoskarn and ore skarn. Andraditic garnet is the main skarn mineral; the pyroxene belongs to the diopside-hedenbergite series. The skarnification started with pluton emplacement and metamorphism of carbonate rocks followed by prograde metasomatism and the formation of anhydrous minerals like garnet and pyroxene. The next stage resulted in retro gradation of anhydrous minerals along with the formation of oxide minerals (magnetite and hematite followed by the formation of hydrosilicate minerals like epidote, actinolite, chlorite, quartz, sericite and sulfide mineralization. In addition to Fe, Si and Mg, substantial amounts of Cu, along with volatile components such as H2S and CO2 were added to the skarn system. Skarn mineralogy and geochemistry of the igneous rocks indicate an island arc or subduction-related origin of the Fe-Cu skarn deposit.

  11. Diagenetic Reactions in Reservoir Strata and Geochemical Properties of Pore Fluid and Its Origin in Songlian Basin

    Institute of Scientific and Technical Information of China (English)

    楼章华; 蔡希源; 等

    1998-01-01

    The reservoirs of the SOngliao Basin are composed of typical unstable sandstones,with high percentages of volcanic fragments and feldspar,In the course of sedimentation and burying,a series of physical and chemical reactions took place between minerals and pore water and water-rock reactions and ion exchange caused changes in ion assemblage of pore water,Hydration-hydrolysis,dissolution and the albitization of feldspar made many ions free from their framework and inter into the pore water,and induced the precipitation of a large amount of authigenic minerals such as smectite and chlorite,During the diagenesis of sandstone.diagenetic reactions involved several stages with increasing depth,and so did the precipitation of authigenic minerals and the transformaiton of minerals.The migration of ions is related with the precipitation,transformation and dissolution of authigenic minerals.Thus,to deepen our study on sandstone diagenesis is an important link for the analysis of ion migration in the evolution of pore water ,the origin and evolution of pore water could be tracked in terms of the geochemistry of fluid inclusions in authigenic minerals.And the isotopic composition of the authigenic mineral calcite can provide its genetic information.

  12. Geochemistry of abyssal peridotites from the super slow-spreading Southwest Indian Ridge near 65°E: Implications for magma source and seawater alteration

    Indian Academy of Sciences (India)

    Zhigang Zeng; Qiaoyun Wang; Xiaomei Wang; Shuai Chen; Xuebo Yin; Zhaoxue Li

    2012-10-01

    The geochemical characteristics of abyssal peridotite samples from one dredge station (27° 49.74′S, 65° 02.14′E, water depth 4473 m) on the super slow-spreading Southwest Indian Ridge (SWIR) near 65°E were investigated. Abyssal peridotites recovered from this site were comprised mainly of lizardite, chlorite, carbonate and magnetite with minor amounts of talc, pyroxene phenocrysts and sparse olivines. Serpentinites exhibit talc veins and major serpentine derived from serpentinization with relict olivine granuloblasts. Olivine grains in serpentinites display exsolution lamellae, indicating the occurrence of talc reduction or decompression during seawater–rock interaction. Pyroxene shows clear cleavage in two directions, with clinopyroxene or orthopyroxene exsolution lamellae. By contrast, bulk rock trace element patterns of serpentinites reveal depletion in most incompatible elements, similarly to the depleted midocean ridge basalt mantle composition, indicating that the SWIR peridotites originated from a depleted mantle source magma and have experienced partial melting. Meanwhile, Rb, Ba, U, Pb, Sr, Li anomalies and the Ce/Pb ratio suggest that these serpentinites have been strongly altered by seawater.

  13. MAGNETITE-HEMATITE IRON ORE OCCURRENCES IN THE TRIASSIC-PALEOZOIC METAMORPHIC COMPLEX OF MEDVEDNICA MOUNTAIN, CROATIA

    Directory of Open Access Journals (Sweden)

    Ivan Jurković

    2005-12-01

    Full Text Available Iron ore occurrences are situated on the south-eastern slopes of the Medvednica Mountain. They occur as discontinous, decameters long and 2-3.5 m thick bedded, poorly mineralized (15-35 % Fe lenses. A narrow, 6 km long, ore zone strikes NE-SW from Tisova Peć to Pustodol-Adolfovac. It is spatially and genetically bounded to the basic volcanogenic-sedimentary series (SEDEX-type, metamorphosed in greenschists during Cretaceous under P 3-3.5 kbar and T 350-400°C. The main minerals of the paragenesis are: quartz, chlorite, hematite, magnetite, stilpnomelane, martite. Similar types of Neo-Proterozoic and Early Paleozoic iron deposits were found in eastern Bosnia - western Serbia, western Macedonia and in the Serbo-Macedonian Mass. In the Triassic period of the Dinarides, magnetite-hematite deposits occur only as iron skarns or as short veins and small sized bodies of pneumatolytic-hydrothermal origin genetically bounded to gabbro-diorite or syenite stock and dykes. In the Triassic vulcanogenic-sedimentary complexes pointing occur only bedded deposits of red hematite, siderite, as well as locally with Mn-oxide ores. The arguments for the Paleozoic age of the Mt. Medvednica iron deposits are more convincing than those proposing theoretically possible Triassic age. The structures, textures and parageneses of the Mt. Medvednica magnetite-hematite occurrences are very similar only to the iron ores situated in the Early Paleozoic metamorphic complexes.

  14. Ion microprobe (SHRIMP dates complex granulite from Santa Catarina, southern Brazil

    Directory of Open Access Journals (Sweden)

    LÉO A. HARTMANN

    2000-12-01

    Full Text Available Complex polymetamorphic granulites have been dated in the Santa Catarina granulite complex of southern Brazil through SHRIMP study of zircon. This complex is dominated by intermediate-acid plutonic rocks and contains small volumes of mafic and ultramafic rocks, and minor quartzite and banded iron formation. Porphyroblasts of orthopyroxene, clinopyroxene and plagioclase in mafic and acid rocks are interpreted as magmatic remnants in a volumetrically dominant granoblastic aggregate (M1 of the same minerals and hornblende. Hornblende formed during a later M2 metamorphic event constitutes rims around pyroxene, but the hornblende is also rimmed by granoblastic simplectites of orthopyroxene, clinopyroxene, hornblende and plagioclase in a second granulite facies event (M3. Chlorite and epidote occur in shear zones (M4. This granulite terrain is part of a Neoproterozoic craton, because it was little affected by the Brasiliano Cycle. The two granulite-facies events (M1 and M3 are dated by U/Pb zircon SHRIMP at about 2.68 and 2.17 Ga, while the magmatic protoliths formed at about 2.72 Ga. The amphibolite facies event (M2 probably occurred close to the 2.17 Ga granulitic metamorphism.

  15. Infrared spectral identification of metasomatic alteration minerals and its implication to gold exploration in Shihu Gold Deposit, Hebei Province, P.R. China

    Science.gov (United States)

    Liu, Jiacheng; Yao, Yuzeng; Wang, Yingpeng; Yuan, Zhou

    2014-11-01

    Hydrothermal alteration is of great importance for mineral exploration, especially the blind ore-hunting due to its larger scale and special zonation compared to the ore bodies. Infrared spectral identification of metasomatic alteration minerals can be done with little or no sample preparation and quantitative result can be obtained. In this paper, 65 wall-rock samples of several horizontal and vertical profiles were selected from Shihu Gold deposit in Hebei Province to do reflectance spectrum measurements by means of rough surface, smooth section and powder with portable ASD FieldSpec®3 spectrometer. ViewspecPro software was used to preprocess the spectrum, and metasomatic alteration minerals were spectrally discriminated by SII (Spectral International Inc) Specmin software package with wavelength of 1100~2500nm. The results shows that: (1) among all the three spectral libraries embedded in SPECMIN software, i.e., ASD, USGS and JPL, ASD spectral library is more suitable for the spectral hydrothermal alteration minerals identification in Shihu Gold Deposit; (2) the observed mineral zonation from wall-rock gneiss to ore-body indicates obvious downtrend of amphibole, chlorite, sericite, carbonate and barite, which is consistent with the microscopic and XRD results; (3) spectral identification of metasomatic alteration minerals is theoretically feasible, which is economic and convenient, and most important of all, the result can be quantitative or semi-quantitative. The results are helpful and successfully applied to the further mineral exploration in Shihu Gold Deposit.

  16. The decolorization of Acid Orange II in non-homogeneous Fenton reaction catalyzed by natural vanadium-titanium magnetite

    Energy Technology Data Exchange (ETDEWEB)

    Liang Xiaoliang; Zhong Yuanhong [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhu Sanyuan; Zhu Jianxi; Yuan Peng [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 (China); He Hongping, E-mail: hehp@gig.ac.cn [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 (China); Zhang Jing [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2010-09-15

    The catalytic activity of natural vanadium-titanium magnetite was investigated in the decolorization of Acid Orange II by non-homogeneous Fenton process. The natural catalysts purified by magnetic separation were characterized using X-ray diffraction (XRD), polarizing microscope, X-ray absorption fine structure (XAFS) analysis and Moessbauer spectroscopy. The obtained results show that the natural samples after magnetic separation mainly contain titanomagnetite, with a small amount of ilmenite and chlorite. Titanomagnetite is doped with vanadium, whose the valency is mainly +3 and occupies the octahedral site. Batch decolorization studies were performed to evaluate the influences of various experimental parameters like initial pH, the amount of catalyst and initial concentration of hydrogen peroxide on the decolorization efficiency of Acid Orange II. The decolorization of the dye mainly relied on degradation. The degradation efficiency was strongly dependent on pH of the medium where it increased as the pH decreased in acid range. The increase of catalyst and hydrogen peroxide could accelerate the degradation. The catalytic property of natural vanadium-titanium magnetite in the degradation of Acid Orange II was stronger than that of synthetic magnetite (Fe{sub 3}O{sub 4}). The catalytic activity of the natural samples was greatly related to the titanomagnetite content. The degradation process was dominated by heterogeneous Fenton reaction, complying with pseudo-first-order rate law. The natural catalyst has a good catalytic stability.

  17. Effect of cleaning methods on bond strength of self-etching adhesive to dentin

    Directory of Open Access Journals (Sweden)

    Juliana Delatorre Bronzato

    2016-01-01

    Full Text Available Aim: The aim of this study was to investigate the influence of cleaning methods to remove zinc oxide-eugenol-based root canal sealer (Endomethasone on the bond strength of the self-etching adhesive to dentin. Materials and Methods: Twenty crowns of bovine incisors were cut to expose the pulp chamber. A zinc oxide- and eugenol-based sealer was placed for 10 min in contact with the pulp chamber dentin. Specimens were divided into four groups according to the cleaning method of dentin used: G1, no root canal sealer (control; G2, 0.9% sodium chlorite (NaCl; G3, ethanol; and G4, followed by diamond drill. After cleaning, the teeth were restored with composite resin and Clearfil SE Bond. All specimens were sectioned to produce rectangular sticks and dentin/resin interface was submitted to microtensile bond testing. The mean bond strengths were analyzed using ANOVA/Tukey (α = 0.05. Results: G3 and G4 showed bond strengths similar to the G1 (P > 0.05. A significant decrease in the bond strength in the G2 was observed (P < 0.05. G1, G3, and G4, the predominant failure mode was the mixed type. The prevalence of adhesive failure mode was verified in the G2. Conclusion: The cleaning methods affected the bond strength of the self-etching adhesive to dentin differently.

  18. Effect of the smear layer in the removal of calcium hydroxide from root canal walls

    Directory of Open Access Journals (Sweden)

    Hakan Arslan

    2012-01-01

    Full Text Available Background: The aim of this study was to investigate whether the smear layer influences the removal of calcium hydroxide from the root canal with manual or rotary instruments. Materials and Methods: The root canals of 48 freshly extracted single-rooted maxillary incisors were prepared to apical size 40 (n=40 and finally irrigated with sodium hypochlorite (group A, or ethylene diamine tetra acetic acid (EDTA followed by sodium hypo chlorite (group B. 20 teeth were assigned to each group, while the remaining eight teeth served as positive and negative controls. Each group was divided into two subgroups of 10 teeth (subgroup I - calcium hydroxide was removed with master apical file; subgroup II - with profile file; and, in all removal procedures, citric acid was used for irrigation. The percentage of calcium hydroxide-[Ca(OH [Ca(OH 2 ] coated surface area was calculated by image processing analysis. Results: Considering the root canal as a whole, the removal of Ca(OH 2 from the dentinal walls in group B showed significantly better results (P<0.05 as compared to group A. Conclusions: Under the conditions of this study, it can be concluded that the smear layer is important in the removal of calcium hydroxide.

  19. Microstructure of a Planting Material Consisting of Nutrition-Expansive Perlitic-Cement Composites

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ji-ru; LIU Zu-de

    2003-01-01

    An ecotypic revetment material consisting of nutrition-expansive perlitic-cement composites is introduced. This planting material can combine vegetation recovery with slope protection. The XRD, SEM and image analysis techniques were used to study its composition and microstructure. Its strength was measured by an electro-hydraulic servo-controlled testing machine. The results show the unconfined compressive strength is about 393.6 kPa, and the average elastic modulus is about 47.0 MPa. The quartz, felspar, chlorite and calcite are the main non-clay minerals in the planting material. Its particles are mainly spherical,and the range of the equivalent diameter is 1.83 to 15.96 μm. The results also show the planting material contains a large amount of micro non-capillary and capillary pores, and has a microstructure characteristic of honeycomb and coralline. CSH gel produced by hydration of cement increases the strength and water stability of the particles. The anisotropy and slight orientation of the particles increase the void cross-section area,providing an explanation of the high permeability for the planting material.The better porosity of the planting material is apt tokeep moisture and nutriment, provides oxygen for plant root breathing, and aids to exhaust the carbon dioxide by means of exchanging with atmosphere, hence it can facilitate vegetation.

  20. (Per)chlorate reduction by an acetogenic bacterium, Sporomusa sp., isolated from an underground gas storage.

    KAUST Repository

    Balk, Melike

    2010-08-03

    A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5-0.8 microm in diameter, and 2-8 microm in length, growing as single cells or in pairs. The cells grew optimally at 37 degrees C, and the pH optimum was around 7. Strain An4 converted various alcohols, organic acids, fructose, acetoin, and H(2)/CO(2) to acetate, usually as the only product. Succinate was decarboxylated to propionate. The isolate was able to respire with (per)chlorate, nitrate, and CO(2). The G+C content of the DNA was 42.6 mol%. Based on the 16S rRNA gene sequence analysis, strain An4 was most closely related to Sporomusa ovata (98% similarity). The bacterium reduced perchlorate and chlorate completely to chloride. Key enzymes, perchlorate reductase and chlorite dismutase, were detected in cell-free extracts.

  1. Clay minerals in uraniferous deposit of Imouraren (Tim Mersoi basin, Niger): implications on genesis of deposit and on ore treatment process

    International Nuclear Information System (INIS)

    Nigerian uraniferous deposits are located in carboniferous and Jurassic formations of Tim Mersoi basin. AREVA is shareholder of 3 mine sites in this area: SOMAIR and COMINAK, both in exploitation since 1960's and IMOURAREN, 80 km further South, whose exploitation is planned for 2015. Mineralization of Imouraren deposit is included in the fluvial formation of Tchirezrine 2 (Jurassic), composed of channels and flood plains. Facies of channel in-fillings range from coarse sandstones to siltstones, while overflow facies are composed of analcimolites. Secondary mineralogy was acquired during 2 stages: 1- diagenesis, with formation of clay minerals, analcime, secondary quartz and albites, and 2- stage of fluids circulations, which induced alteration of detrital and diagenetic minerals, formation of new phases and uranium deposition. A mineralogical zoning, at the scale of deposit resulted from this alteration. The heterogeneity of Tchirezrine 2, at the level of both facies and mineralogy, is also evidenced during ore treatment, as ore reacts differently depending on its source, with sometimes problems of U recovery. Ore treatment tests showed that analcimes and chlorites were both penalizing minerals, because of 1- the sequestration of U-bearing minerals into analcimes, 2- their dissolution which trends to move away from U solubilization conditions (pH and Eh) and to form numerous sulfates, and 3- problems of percolation. A detection method of analcime-rich ores, based on infrared spectroscopy, was developed in order to optimize ore blending and so to reduce negative effects during ore treatment process. (author)

  2. Uranium speciation in the environment: study of opals from Nopal I (Mexico) and mill tailings from Gunnar (Canada)

    International Nuclear Information System (INIS)

    Understanding the processes of uranium migration and sequestration is an important issue for the prediction of radionuclide retardation in the vicinity of uranium mine tailings sites or for the safety assessment of potential high-level nuclear waste repositories. Uranium speciation, controlled by biotic and abiotic factors, represents a key parameter for the control of uranium transfer in the environment. This study firstly deals with uranium speciation in opals from the Nopal I uranium deposit (Mexico). Microscopic observations of opals at the nano-scale revealed the occurrence of vorlanite, cubic CaUO4. This was the first time this rare calcium uranate has been found displaying a cubic morphology, in agreement with its crystal structure. Nopal I opals have been further investigated through time-resolved laser fluorescence spectroscopy. The opals spectra and their comparison with those of experimentally produced standards indicate occurrence of mono- or polymeric uranyl complexes (associated or not with calcium or phosphate) sorbed onto internal surface of opal around pH 7-8. Finally, the speciation of uranium was studied in mill tailings from Gunnar (Canada). In the first tailings site, uranium primarily occurs as monomeric, inner-sphere uranyl complexes sharing edges with Fe(O,OH)6 octahedral sites of iron-oxy-hydroxides and chlorite. Our results suggested that U(VI) co-precipitates with iron (oxy-hydr)oxides predominate in the second tailings sites. Therefore uranium mobility in Gunnar is governed by sorption/desorption and dissolution/(co)precipitation processes. (author)

  3. The effects of low level chlorination and chlorine dioxide on biofouling control in a once-through service water system

    International Nuclear Information System (INIS)

    Continuous chlorination has been successfully used for the control of Corbicula at a nuclear power plant located on the Chattahoochee River in southeastern Alabama, since 1986. The purpose of this study was to investigate further minimization of chlorine usage and determine if chlorine dioxide is a feasible alternative. Four continuous biocide treatments were evaluated for macro and microfouling control effectiveness, operational feasibility, and environmental acceptability. One semi-continuous chlorination treatment was also evaluated for macrofouling control effectiveness. Higher treatment residuals were possible with chlorine dioxide than with chlorination due to the river discharge limitations. At the levels tested, continuous chlorine dioxide was significantly more effective in providing both macro and microfouling control. Semi-continuous chlorination was just as effective as continuous chlorination for controlling macrofouling. The Corbicula treatment programs that were tested should all provide sufficient control for zebra mussels. Chlorine dioxide was not as cost effective as chlorination for providing macrofouling control. The semi-continuous treatment save 50% on chemical usage and will allow for the simultaneous treatment of two service water systems. Chlorite levels produced during the chlorine dioxide treatments were found to be environmentally acceptable. Levels of trihalomethanes in the chlorinated service water were less than the maximum levels allowed in drinking water

  4. POLARIMETRIC SIGNATURES IDENTIFICATION FOR DIFFERENT FEATURES IN RADARSAT-2 POLSAR IMAGE: A CASE STUDY OF HALAYIB AREA, EGYPT

    Directory of Open Access Journals (Sweden)

    A. H. Nasr

    2016-06-01

    Full Text Available In fully polarized SAR (PolSAR data the returned signal from a target contains all polarizations. More information about this target may be inferred with respect to single-polarization. Distinct polarization separates targets due to its different backscattering responses. A Radarsat-2 PolSAR image acquired on December 2013 of part of Halayib area (Egypt was used in this study. Polarimetric signatures for various features (Wadi deposits, Tonalite, Chlorite schist, and Radar penetrated areas were derived and identified. Their Co-polarized and Cross-polarized signatures were generated, based on the calculation of the backscattered power at various ellipticity and orientation angles. Graphical 3D-representation of these features was provided and more details of their physical information are depicted according to their different polarization bases. The results illustrate that polarimetric signatures, obtained due to factors like surface roughness, dielectric constant and feature orientation, can be an effective representation for analyzing various features. The shape of the signature is significant and can also indicate the scattering mechanisms dominating the features response.

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

    International Nuclear Information System (INIS)

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

  6. Antioxidant and DNA damage protecting potentials of polysaccharide extracted from Phellinus baumii using a delignification method.

    Science.gov (United States)

    Jin, Qun-Li; Zhang, Zuo-Fa; Lv, Guo-Ying; Cai, Wei-Ming; Cheng, Jun-Wen; Wang, Jian-Gong; Fan, Lei-Fa

    2016-11-01

    A delignification method was employed to extract the polysaccharide from the fruiting body of Phellinus baumii. The three parameters, processing temperature, ratio of water to raw material and amount of acetic acid every time were optimized using the Box-Behnken design. As a result, the optimal extraction conditions were: processing temperature 70.3°C, ratio of water to raw material of 34.7mL/g and amount of acetic acid of 0.32mL every time. Under these conditions, the highest yield of polysaccharide (10.28%) was obtained. The main fraction (PPB-2) purified from PPB was composed of fucose, arabinose, galactose, glucose, xylose and mannose, while glucose was the predominant monosaccharide. PPB-2 exhibited noticeable antioxidant activity and strong protection against oxidative DNA damage. These findings implied that acid-chlorite delignification was a superior method to extract the polysaccharide from P. baumii and PPB-2 may be useful for cancer chemoprevention. PMID:27516306

  7. Hyperspectral surface materials map of quadrangle 3166, Jaldak (701) and Maruf-Nawa (702) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  8. Hyperspectral surface materials map of quadrangles 3666 and 3766, Balkh (219), Mazar-e Sharif (220), Qarqin (213), and Hazara Toghai (214) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  9. Hyperspectral surface materials map of quadrangle 3362, Shindand (415) and Tulak (416) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  10. Hyperspectral surface materials map of quadrangle 3462, Herat (409) and Chishti Sharif (410) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  11. Hyperspectral surface materials map of quadrangle 3366, Gizab (513) and Nawer (514) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  12. Hyperspectral surface materials map of quadrangles 3360 and 3460, Kawir-e Naizar (413), Kohe-Mahmudo-Esmailjan (414), Kol-e Namaksar (407), and Ghoriyan (408) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  13. Hyperspectral surface materials map of quadrangle 3470, Jalalabad (511) and Chaghasaray (512) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  14. Hyperspectral surface materials map of quadrangle 3564, Jowand (405) and Gurziwan (406) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  15. Hyperspectral surface materials map of quadrangles 2964, 2966, 3064, and 3066, Shah-Esmail (617), Reg-Alaqadari (618), Samandkhan-Karez (713), Laki-Bander (611), Jahangir-Naweran (612), and Sreh-Chena (707) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Hoefen, Todd M.; Kokaly, Raymond F.; King, Trude V.V.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  16. Hyperspectral surface materials map of quadrangles 2962 and 3062, Gawdezereh (615), Galachah (616), Chahar Burjak (609), and Khan Neshin (610) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Hoefen, Todd M.; Kokaly, Raymond F.; King, Trude V.V.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  17. Hyperspectral surface materials map of quadrangle 3264, Naw Zad-Musa Qala (423) and Dihrawud (424) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  18. Hyperspectral surface materials map of quadrangle 3464, Shahrak (411) and Kasi (412) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  19. Hyperspectral surface materials map of quadrangles 3668 and 3768, Baghlan (221), Taluqan (222), Imam Sahib (215), and Rustaq (216) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  20. Hyperspectral surface materials map of quadrangles 3664 and 3764, Char Shengo (123), Shibirghan (124), Jalajin (117), and Kham-Ab (118) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  1. Hyperspectral surface materials map of quadrangle 3164, Lashkar Gah (605) and Kandahar (606) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  2. Hyperspectral surface materials map of quadrangle 3562, Khawja-Jir (403) and Murghab (404) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  3. Hyperspectral surface materials map of quadrangle 3364, Pasaband (417) and Markaz-e Kajiran (418) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  4. Hyperspectral surface materials map of quadrangle 3262, Farah (421) and Hokumat-e-pur-Chaman (422) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  5. Hyperspectral surface materials map of quadrangle 3162, Chakhansur (603) and Kotalak (604) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  6. Hyperspectral surface materials map of quadrangle 3466, La`l wa Sar Jangal (507) and Bamyan (508) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  7. Hyperspectral surface materials map of quadrangle 3568, Pul-e Khumri (503) and Charikar (504) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  8. Hyperspectral Surface Materials Map of Quadrangle 3566, Sangcharak (501) and Sayghan-o-Kamard (502) Quadrangles, Afghanistan, Showing Carbonates, Phyllosilicates, Sulfates, Altered Minerals, and Other Materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  9. Hyperspectral surface materials map of quadrangle 3266, Uruzgan (519) and Moqur (520) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  10. Hyperspectral surface materials map of quadrangle 3368, Ghazni (515) and Gardez (516) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  11. Hyperspectral surface materials map of quadrangle 3770, Faizabad (217) and Parkhaw (218) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  12. Hyperspectral surface materials map of quadrangle 3468, Chak-e Wardak-Siyahgird (509) and Kabul (510) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  13. Hyperspectral surface materials map of quadrangle 3260, Dasht-e-Chah-e-Mazar (419) and Anar Darah (420) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  14. Hyperspectral surface materials map of quadrangle 3570, Tagab-e-Munjan (505) and Asmar-Kamdesh (506) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  15. Hyperspectral surface materials map of quadrangle 3268, Khayr Kot (521) and Urgun (522) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Giles, Stuart A.; Johnson, Michaela R.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  16. Hyperspectral surface materials map of quadrangle 3670, Jurm-Kishim (223) and Zebak (224) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

    Science.gov (United States)

    Kokaly, Raymond F.; King, Trude V.V.; Hoefen, Todd M.; Livo, Keith E.; Johnson, Michaela R.; Giles, Stuart A.

    2013-01-01

    This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,000 feet (15,240 meters (m)), the HyMap™ imaging spectrometer measured reflected sunlight in 128 channels, covering wavelengths between 0.4 and 2.5 μm. The data were georeferenced, atmospherically corrected and converted to apparent surface reflectance, empirically adjusted using ground-based reflectance measurements, and combined into a mosaic with 23-m pixel spacing. Variations in water vapor and dust content of the atmosphere, in solar angle, and in surface elevation complicated correction; therefore, some classification differences may be present between adjacent flight lines. The reflectance spectrum of each pixel of HyMap™ imaging spectrometer data was compared to the reference materials in a spectral library of minerals, vegetation, water, and other materials. Minerals occurring abundantly at the surface and those having unique spectral features were easily detected and discriminated, while minerals having slightly different compositions but similar spectral features were less easily discriminated; thus, some map classes consist of several minerals having similar spectra, such as “Epidote or chlorite.” A designation of “Not classified” was assigned to the pixel when there was no match with reference spectra.

  17. Characterization of potential mineralization in Afghanistan: four permissive areas identified using imaging spectroscopy data

    Science.gov (United States)

    King, Trude V.V.; Berger, Byron R.; Johnson, Michaela R.

    2014-01-01

    As part of the U.S. Geological Survey and Department of Defense Task Force for Business and Stability Operations natural resources revitalization activities in Afghanistan, four permissive areas for mineralization, Bamyan 1, Farah 1, Ghazni 1, and Ghazni 2, have been identified using imaging spectroscopy data. To support economic development, the areas of potential mineralization were selected on the occurrence of selected mineral assemblages mapped using the HyMap™ data (kaolinite, jarosite, hydrated silica, chlorite, epidote, iron-bearing carbonate, buddingtonite, dickite, and alunite) that may be indicative of past mineralization processes in areas with limited or no previous mineral resource studies. Approximately 30 sites were initially determined to be candidates for areas of potential mineralization. Additional criteria and material used to refine the selection and prioritization process included existing geologic maps, Landsat Thematic Mapper data, and published literature. The HyMapTM data were interpreted in the context of the regional geologic and tectonic setting and used the presence of alteration mineral assemblages to identify areas with the potential for undiscovered mineral resources. Further field-sampling, mapping, and supporting geochemical analyses are necessary to fully substantiate and verify the specific deposit types in the four areas of potential mineralization.

  18. Stratigraphic assessment of the Arcelia Teloloapan area, southern Mexico: implications for southern Mexico's post-Neocomian tectonic evolution

    Science.gov (United States)

    Cabral-Cano, E.; Lang, H. R.; Harrison, C. G. A.

    2000-10-01

    Stratigraphic assessment of the "Tierra Caliente Metamorphic Complex" (TCMC) between Arcelia and Teloloapan in southern Mexico, based on photo interpretation of Landsat Thematic Mapper images and field mapping at the 1:100,000 scale, tests different tectonic evolution scenarios that bear directly on the evolution of the southern North American plate margin. The regional geology, emphasizing the stratigraphy of a portion of the TCMC within the area between Arcelia and Teloloapan is presented. Stratigraphic relationships with units in adjacent areas are also described. The base of the stratigraphic section is a chlorite grade metamorphic sequence that includes the Taxco Schist, the Roca Verde Taxco Viejo Formation, and the Almoloya Phyllite Formation. These metamorphic units, as thick as 2.7 km, are covered disconformably by a sedimentary sequence, 2.9 km thick, composed of the Cretaceous marine Pochote, Morelos, and Mexcala Formations, as well as undifferentiated Tertiary continental red beds and volcanic rocks. The geology may be explained as the evolution of Mesozoic volcanic and sedimentary environments developed upon attenuated continental crust. Our results do not support accretion of the Guerrero terrane during Laramide (Late Cretaceous-Paleogene) time.

  19. Evaluation of Water-Mineral Interaction Using Microfluidic Tests with Thin Sections

    Science.gov (United States)

    Oh, Y. S.; Ryu, J. H.; Koh, Y. K.; Jo, H. Y.

    2014-12-01

    For the geological disposal of radioactive wastes, geological settings and groundwater conditions are significantly important because of their effects on a radionuclide migration. One of the preferred host rocks for the radioactive waste disposal is crystalline rock. Fractures in crystalline rocks are main fluid pathways. Groundwater reacts with fracture filling minerals in fracture zones, resulting in physicochemical changes in the minerals and groundwater. In this study, fracture filling mineral-groundwater interactions were investigated by conducting microfluidic tests using thin sections at various conditions (i.e., fluid chemistry and flow rate). Groundwater and rock core samples collected from the KAERI Underground Research Tunnel (KURT) located in the Korea Atomic Energy Research Institute (KAERI) were used in this study. Dominant bedrock is two-mica granite, which contains both biotite and muscovite. Secondary minerals (e.g., chlorite, calcite and clay minerals) occur in fracture and alteration zones. In nature, water-mineral interactions generally take long time. Microfluidic tests were conducted to simulate water-mineral interactions in shorter time with smaller scale. Thin sections of fracture filling minerals, minerals from alteration zones, and natural and synthetic groundwater samples were used for the microfluidic tests. Results showed that water-mineral interactions at various conditions caused changes in groundwater chemistry, dissolution of minerals, precipitation of secondary minerals, and formation of colloids, which can affect radionuclide migration. In addition, the fluid chemistry and flow rate affected characteristics of water-rock interactions.

  20. Geochemistry of Kasnau-Matasukh lignites, Nagaur Basin,Rajasthan (India)

    Institute of Scientific and Technical Information of China (English)

    Prakash K.Singh; Pramod K.Rajak; Mahendra P.Singh; Vijay K.Singh; Amiya S.Naik

    2016-01-01

    The distribution and verticals variation of geochemical components in the Kasnau-Matasukh lignites of Nagaur Basin,Rajasthan,were investigated using microscopy,proximate and ultimate analyses,Rock-Eval Pyrolysis,X-ray diffraction and Fourier Transform Infrared analyses,and major/minor/trace element determination.The relationship of elements with ash content and with macerals have also been discussed.These lignites are stratified,black,dominantly composed of huminite group macerals with subordinated amounts of liptinite and inertinite groups.They are classified as type-Ⅲ kerogen and are mainly gas prone in nature.The concentration (in vol%) of mineral matter is seen to increase towards upper part of seam and so is the concentration (in wt%) of the volatile matter,elemental carbon and sulphur.The common minerals present in these lignitesare mixed clay layer,chlorite,and quartz as identified by X-ray diffraction study.Compared with world average in brown coal,the bulk concentration of Cu is anomalously high in most of the samples while Cd is 2-3 times high and Zn is high in one band.Based on interrelationship,different pyrite forms are noticed to have different preferential enrichment of various elements.The concentration of disseminated pyrite is more than the other pyrite forms and is followed by discrete pyrite grains and massive pyrite.