Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

-1

 

Publications des Unités de recherche de la FR‐EST   (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) 

  Année 2008  Ordre alphabétique 

  ‐ 1 ‐  Sorption and leaching of C‐14‐glyphosate in agricultural soils  Al‐Rajab, AJ; Amellal, S; Schiavon, M  AGRONOMY FOR SUSTAINABLE DEVELOPMENT (2008) 28, 419‐428 

  Abstract: Glyphosate ( N-(phosphonomethyl) glycine) is one of the most widely used herbicides in the world to control weeds in agricultural and urban areas. Its increasing use requires special attention to its transfer from terrestrial to aquatic environments. However, knowledge on the leaching of glyphosate and its metabolite aminomethylphosphonic acid ( AMPA) is scarce. Here we aimed to assess the dynamic interactions between glyphosate sorption and leaching; and to identify the main factors that influence the two processes in three undisturbed agricultural soils using microlysimeters under outdoor conditions. We studied the sorption, desorption and leaching of C-14-labelled glyphosate on three soils using batch experiments in the laboratory and lysimeters under natural conditions for 11 months. The laboratory results showed that glyphosate was strongly adsorbed, yielding empirical constants of Freundlich sorption isotherms (K-f) of 16.6 for the clay loam soil, 33.6 for the silt clay loam soil and 34.5 for the sandy loam soil, with n(f) close to 1 in all three cases. Glyphosate was also weakly desorbed, i.e. 5 to 24% ( w)of initially sorbed glyphosate. Sorption and desorption were only pH-dependent. The outdoor results showed that nearly 70% of the initial glyphosate was present in the soil in a non-extractable form at the beginning of the experiment. Conversely, only less than 20% of the initial glyphosate is present in the soil in a nonextractable form after 11 months. These findings suggest that the non-extractable residues become available and take part in biodegradation and leaching. The amounts of C-14-glyphosate derivatives leached were less than 0.28% of the initially applied glyphosate. HPLC analyses showed that the AMPA metabolite generally represented up to 100% of the residues present in the leachates. The results of leaching were highly influenced by the hydrodynamic properties and the biodegradation capacities of the soils. Although glyphosate residues were found in low concentrations in the leachates for almost a year, the contamination of groundwater does not seem to be a concern, regardless of the soil type, if the herbicide is used in accordance with good agricultural practice. DOI : 10.1051/agro:2008014 

 

  ‐ 2 ‐  Predicting methane accumulations generated from humic carboniferous coals in the Donbas fold belt (Ukraine) Alsaab, D; Elie, M; Izart, A; Sachsenhofer, RF; Privalov, VA  AAPG BULLETIN (2008) 92, 1029‐1053 

  Abstract: The numerical modeling of the Ukrainian part of the Donbas fold belt indicates that the coalification pattern was controlled mainly by the maximum burial depth of coal seams and the heat flow (HF) (40-75 mW/m(2)) during the Permian. The coalification pattern was overprinted by magmatic events during the Late Permian in the south syncline (150 mW/m(2)) and during the Permian-Triassic in the north of the Krasnoarmeisk region (120 mW/m2). The coalification pattern shows a strong increase in vitrinite reflectance values toward the east and southeastern parts of the study area likely caused by (1) an eastward increase in burial depth, (2) a probable eastward increase in HF, and, (3) probable magmatic activity. An increase in total erosion toward the eastern and southeastern parts was also observed with a maximum erosional amount of approximately 8 km (5 mi) in the southeastern part of the study area. The basin modeling of this area predicts that the main phase of hydrocarbon generation occurred during the Carboniferous-Early Permian subsidence. The magmatic events that occurred during the Permian-Triassic caused renewed pulses of hydrocarbon generation. A large amount of the generated hydrocarbons was lost to the surface because of a lack of seals. However, the numerical simulation predicts accumulations of about 2 tcf (57 billion m 3) of methane generated from Carboniferous coals in the south and main synclines, where Lower Permian seal rocks are preserved. Finally, this study provides data on methane resources along the northern flank DOI : 10.1306/03250807053 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

-2

‐ 3 ‐  Comparison of hydrocarbon gases (C‐1‐C‐5) production from Carboniferous Donets (Ukraine) and Cretaceous  Sabinas (Mexico) coals  Alsaab, D; Elie, M; Izart, A; Sachsenhofer, RF; Privalov, VA; Suarez‐Ruiz, I; Martinez, L  INTERNATIONAL JOURNAL OF COAL GEOLOGY (2008) 74, 154‐162 

  Abstract: The main purpose of this contribution is to compare the ability of Carboniferous coals from the Donets Basin of the Ukraine and Cretaceous coal from the Sabinas Basin of the Mexico to generate hydrocarbon gases (C-1-C-5). Two bituminous coals from the Donets Basin (2c10YD and 111 Dim; 0.55 and 0.65%R-r respectively) and one bituminous coal from the Sabinas Basin (Olmos, 0.92%R-r) were studied using heating experiments in a confined-pyrolysis system. The highest rank reached during the heating experiments corresponds to the anthracite stage (2.78 and 2.57%R-r) for the 2c10YD and 111 Dim coals and (2.65%R-r) for the Olmos coal. The composition of the generated (C1-C5) gases was evaluated using a thennodesorption-multidimensionaI gas chromatography. The results show that the Carboniferous Donets coals produced more wet gas and methane during pyrolysis than the Cretaceous Olmos coal. This is probably due to their higher liptinite (620%) and collodetrinite content and to the loss of a major part of the petroleum potential of the Olmos coal during natural coalification. C2-C5 compounds are mainly derived from the cracking of liquid hydrocarbons. Ethane is the most stable compound and formed from the cracking of higher hydrocarbon component. Large amounts of methane (up to 81 mg/g coal for the Donets coals and 50 mg/g coal for the Sabinas coal) were formed at high temperatures by cracking of previously formed heavier hydrocarbons and by clealkylation of the coal matrix. A linear relationship was observed between methane generation and the maturity level of both coal types. (0 2007 Elsevier B.V. All rights reserved. DOI : 10.1016/j.coal.2007.11.006 

 

  ‐ 4 ‐  Implications of spatial and temporal evolutions of thermal parameters in basin modelling  Amir, L; Martinez, L; Disnar, JR; Michels, R; Vigneresse, JL; Robin, C; Guillocheau, F  MARINE AND PETROLEUM GEOLOGY (2008) 25, 759‐766 

  Abstract: This paper presents the Paris Basin numerical modelling at a high sequential resolution scale (1-5 my). Simulations were carried out from the computation of thermal gradients and conductivities varying with the burial of genetic units. Geologic heating rates are also calculated throughout the burial of the stratigraphic sequences. Thermal energies are then deduced. The Paris Basin is well known for its hydrocarbon potential in Liassic sediments. This study is focused on an eastwest cross-section through the basin. The results show spatial and temporal variations of thermal parameters from the western to the eastern part of the profile. The reactivation of Hercynian fracture systems during the Mesozoic may be responsible for the computed variations in thermal conductivities and thermal gradients. Major geodynamic events also played a role in the simulated thermal history. Variations of the thermal energy are observed and are well correlated with the burial history of the basin. We suggest linking the simulated thermal energies to the thermal cracking of the organic matter. Our results are consistent with the prediction of hydrocarbon potential in the Cretaceous period. Consequently, this approach provides new insights to improve petroleum generation modelling issues. (C) 2008 Elsevier Ltd. All rights reserved. DOI : 10.1016/j.marpetgeo.2008.03.006 

 

  ‐ 5 ‐  Chaotic particle sedimentation in a rotating flow with time‐periodic strength  Angilella, JR  PHYSICAL REVIEW E (2008) 78, ‐ 

  Abstract: Particle sedimentation in the vicinity of a fixed horizontal vortex with time-dependent intensity can be chaotic, provided gravity is sufficient to displace the particle cloud while the vortex is off or weak. This "stretch, sediment, and fold" mechanism is close to the so-called blinking vortex effect, which is responsible for chaotic transport of perfect tracers, except that in the present case the vortex motion is replaced by gravitational settling. In the present work this phenomenon is analyzed for heavy Stokes particles moving under the sole effect of gravity and of a linear drag. The vortex is taken to be a fixed isolated point vortex, the intensity of which varies under the effect of either boundary conditions or volume force. When the unsteadiness of the vortex is weak and the free-fall velocity is of the order of the fluid velocity, and the particle response time is small, the particle motion equation can be written asymptotically as a perturbed Hamiltonian system, the phase portrait of which displays a homoclinic trajectory. A homoclinic bifurcation is therefore likely to occur, and the contribution of particle inertia to the occurrence of this bifurcation is analyzed asymptotically by using Melnikov's method. DOI : 10.1103/PhysRevE.78.066310 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

-3

‐ 6 ‐  A spectrophotometric measurement of soil cation exchange capacity based on cobaltihexamine chloride  absorbance  Aran, D; Maul, A; Masfaraud, JF  COMPTES RENDUS GEOSCIENCE (2008) 340, 865‐871 

  Abstract: Among numerous methods for cation exchange capacity (CEC) determination for soils and sediments, the cobaltihexamine chloride method is frequently used due to its ability to measure CEC at soil pH. After exchange with Co(NH3)(6)(3+) ions, CEC is estimated via the measurement of the Co remaining in solution. The modified method proposed allows a more rapid determination of CEC based on the measurement of the absorbance at 472 nm of the cobaltihexamine chloride solution before and after exchange. This method has been applied to various soil's horizons from four sites, selected to cover a wide range of CEC and pH values. The model obtained allows one to calculate CEC from absorbance at 472 nm with 95% confidence intervals. As CEC is of relevant meaning in agronomical and environmental purposes, and more recently in ecotoxicological studies, this modified method can be proposed as a rapid test for CEC evaluation. To cite this article: D. Aran et al., C. R. Geoscience 340 (2008). (C) 2008 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved. DOI : 10.1016/j.crte.2008.07.015 

 

  ‐ 7 ‐  Improving models of forest nutrient export with equations that predict the nutrient concentration of tree  compartments  Augusto, L; Meredieu, C; Bert, D; Trichet, P; Porte, A; Bosc, A; Lagane, F; Loustau, D; Pellerin, S; Danjon, F;  Ranger, J; Gelpe, J  ANNALS OF FOREST SCIENCE (2008) 65, ‐ 

  Abstract: The objective of this study was to explore the distribution of major nutrients (N, P, K, Ca and Mg) in the aboveground compartments of an intensively managed tree species (Pinus pinaster Ait.). A total of 53 trees were cut down in even-aged stands respectively 8, 16, 26, 32 and 40 years old. The nutrient concentrations of the aboveground compartments were analysed. Nutrient concentrations of foliage did not vary with any of the variables used, except needle age. Nutrient concentrations of living branches, stem bark, stem sapwood, stem heartwood, stemwood and stem decreased with increasing branch diameter, bark thickness, sapwood thickness and heartwood thickness, respectively. Beyond a certain value of the predictive variable (stem diameter approximate to 15 cm; branch diameter approximate to 2.5 cm), the concentration of all the nutrients stabilised. A 50 year-old pine stand was used to obtain a validation dataset for nitrogen concentration. For this nutrient, the regression relationships gave satisfactory estimates for most compartments (mean error = 12-25%) and particularly for the stem. A procedure is proposed to estimate the nutrient exports associated with harvests of Pinus pinaster biomass. DOI : 10.1051/forest:2008059 

 

  ‐ 8 ‐  Distribution of organic pollutants and natural organic matter in urban storm water sediments as a function of  grain size  Badin, AL; Faure, P; Bedell, JP; Delolme, C  SCIENCE OF THE TOTAL ENVIRONMENT (2008) 403, 178‐187 

  Abstract: The sealing of surfaces in urban areas makes storm water management compulsory. Contaminated particles carried from urban surfaces are deposited in infiltration ponds. This gives rise to a highly organic (11% DW) contaminated sedimentary layer (Zn:1.2 mg/g, Cd:15 mg/kg) that could threaten groundwater quality. During infiltration, particle arrangement impacts infiltrating water and sediment exchanges. In this context, understanding particle arrangement and leachable components is essential. This study investigates Organic Matter (OM) not only as a pollutant but also as a substrate and a structuring element. The leachable fraction was collected and grain size fractionation was performed. OM of sediments and isolated fractions were characterized by measuring organic carbon content, isolating aromatic hydrocarbons, saturated hydrocarbons and polar compounds after dichloromethane extraction, and by gas chromatography-mass spectrometry (GCMS) molecular analyses. The organic compounds observed were petroleum byproducts (steranes and terpanes, unresolved complex mixture (UCM) and polycyclic aromatic hydrocarbons (PAH)), but plant and bacteria biomarkers were also found (phytol and derivatives, sterols). Leachable OM consisted of 6% of sediment OM (associated with particles >0.45 mu m). This leachable OM is easily extractable by dichloromethane (96%) and contains fewer macromolecules than other fractions. isolated grain size fractions showed dissimilarities (total organic carbon from 3.5 mg/g to 88.6 mg/g, extraction rate from 24 to 96%, aromatic hydrocarbon distribution) and similarities (proportions of aromatic and saturated hydrocarbons and polar compounds, molecular distribution of saturated hydrocarbons and polar compounds). The results suggest that organic macromolecules take part in the aggregation of sediments and prevent fine particles ( MS2. Close inspection of the electrokinetic results reveals small to significant variations of the pI valuesdepending on the phage considered-with respect to the concentration of indifferent NaNO3 electrolyte. This indicates that features other than chemical and electrostatic in nature play a key role in determining the pI and more generally the electrophoretic mobility mu of viral particles. A qualitative interpretation is given and is based on the consideration of inner electro-osmotic flow within the isolated or aggregated particles. The impact of the flow properties within the particles is further in agreement with recent theoretical formalism developed for the electrokinetics of soft multiplayer particles, the phages analyzed here being some illustrative examples. The determination and qualitative interpretation of the surface properties of the viral particles as reported in the current study are commented within the context of water treatment especially concerning viral removal by membrane filtration processes. (c) 2008 Elsevier Ltd. All rights reserved. DOI : 10.1016/j.watres.2008.02.007 

 

  ‐ 89 ‐  Impact of chemical and structural anisotropy on the electrophoretic mobility of spherical soft multilayer  particles: The case of bacteriophage MS2  Langlet, J; Gaboriaud, F; Gantzer, C; Duval, JFL  BIOPHYSICAL JOURNAL (2008) 94, 3293‐3312 

  Abstract: We report a theoretical investigation of the electrohydrodynamic properties of spherical soft particles composed of permeable concentric layers that differ in thickness, soft material density, chemical composition, and flow penetration degree. Starting from a recent numerical scheme developed for the computation of the direct-current electrophoretic mobility (mu) of diffuse soft bioparticles, the dependence of mu on the electrolyte concentration and solution pH is evaluated taking the known three-layered structure of bacteriophage MS2 as a supporting model system (bulk RNA, RNA-protein bound layer, and coat protein). The electrokinetic results are discussed for various layer thicknesses, hydrodynamic flow penetration degrees, and chemical compositions, and are discussed on the basis of the equilibrium electrostatic potential and hydrodynamic flow field profiles that develop within and around the structured particle. This study allows for identifying the cases where the electrophoretic mobility is a function of the inner structural and chemical specificity of the particle and not only of its outer surface properties. Along these lines, we demonstrate the general inapplicability of the notions of zeta potential () and surface charge for quantitatively interpreting electrokinetic data collected for such systems. We further shed some light on the physical meaning of the isoelectric point. In particular, numerical and analytical simulations performed on structured soft layers in indifferent electrolytic solution demonstrate that the isoelectric point is a complex ionic strengthdependent signature of the flow permeation properties and of the chemical and structural details of the particle. Finally, the electrophoretic mobilities of the MS2 virus measured at various ionic strength levels and pH values are interpreted on the basis of the theoretical formalism aforementioned. It is shown that the electrokinetic features of MS2 are to a large extent determined not only by the external proteic capsid but also by the chemical composition and hydrodynamic flow permeation of/within the inner RNA-protein bound layer and bulk RNA part of the bacteriophage. The impact of virus aggregation, as revealed by decreasing diffusion coefficients for decreasing pH values, is also discussed. DOI : 10.1529/biophysj.107.115477 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 37

‐ 90 ‐  High temperature behavior of electrostatic precipitator ash from municipal solid waste combustors  Le Forestier, L; Libourel, G  JOURNAL OF HAZARDOUS MATERIALS (2008) 154, 373‐380 

  Abstract: Municipal solid waste (MSW) flue gas residues require further treatment prior to disposal or reuse, and vitrification is one of the main solidification-stabilization processes. This paper investigates the high temperature behavior of MSW flue gas residues, performed in laboratory experiments up to 1400 degrees C, and coupled with thermogravimetric analyses, X-ray diffraction, chemical and electron microprobe analyses. Melting temperatures of electrostatic precipitator (ESP) ash are in the range of 1202-1272 degrees C, whereas semi-dry scrubber residues melt between 1900 and 2300 degrees C. We show that the mean liquidus temperature of flue gas residues can be simply evaluated from their CaO content, by using the CaO-SiO2Al2O3 ternary diagram. For ESP ash, the liquidus phase is a Zn-rich aluminous spinel, followed by anorthite at 1225 degrees C, and melilite at 1190 degrees C. The total mass loss reaches 18 wt.% at 1300 degrees C. Moreover, 90% of evaporation takes place below 1000 degrees C, linked to evaporation of C, Cl, S, Na, K, and of the toxic metals Hg, Cd, Pb, Cu. Due to the high partial pressure of chlorine during heating, chloride is the most probable form of evaporation for Cd, Pb, and Cu. However, most of Zn, Cr, Ni, Sb and Sn remain in the vitrified product. (C) 2007 Elsevier B.V. All rights reserved. DOI : 10.1016/j.jhazmat.2007.10.034 

 

  ‐ 91 ‐  Comment on "The biosphere: A homogeniser of Pb‐isotope signals" by C. Reimann, B. Flem, A. Arnoldussen, P.  Englmaier, TE Finne, F. Koller and O. Nordgulen  Le Roux, G; Sonke, JE; Cloquet, C; Aubert, D; de Vleeschouwer, F  APPLIED GEOCHEMISTRY (2008) 23, 2789‐2792 

  Abstract: DOI : 10.1016/j.apgeochem.2008.05.017 

 

  ‐ 92 ‐  Adsorption of phenanthrene on activated carbon increases mineralization rate by specific bacteria  Leglize, P; Alain, S; Jacques, B; Corinne, L  JOURNAL OF HAZARDOUS MATERIALS (2008) 151, 339‐347 

  Abstract: Bioavailability of polycyclic aromatic hydrocarbons (PAH) in soil is affected by PAH sorption to solid phase. We studied the influence of activated carbon (AC) on phenanthrene (PHE) mineralization by five degrading bacterial strains isolated from contaminated soil. PHE adsorption on AC was important and reduced PHE aqueous concentration LIP to 90%. PHE degradation was improved in the presence of activated carbon with three of the bacterial strains, named NAH 1, MATE3 and MATE7, which produced biofilms, whereas it was not improved with the two other ones, which did not produce biofilms, MATE 10 and MATE12. Monitoring PHE distribution during incubation showed that aqueous PHE concentration was significantly higher with the biotilm-producing NAH1 than with MATE10. Bacterial adhesion on AC was also investigated. The precoating of AC with PHE increased NAH1 and MATE3 adhesion to the solid surface (>16 and >13%, respectively). Bacterial properties, such as biofilm production and adhesion to AC capacity seemed to be related to their ability to optimize PHE degradation by improving PHE diffusion and reducing diffusion path length. (C) 2007 Elsevier B.V. All rights reserved. DOI : 10.1016/j.jhazmat.2007.05.089 

 

  ‐ 93 ‐  Spatial variability of nutrient stocks in the humus and soils of a forest massif (Fougeres, France)  Legout, A; Walter, C; Nys, C  ANNALS OF FOREST SCIENCE (2008) 65, ‐ 

  Abstract: In this study, the spatial distribution of nutrient stocks (K, Ca, Mg and P) was examined in humus and soils at the forest massif scale (Foug res forest, France). A random stratified sampling plan including 100 sampling points was used and three potential variation factors of nutrient stocks were tested: age of stand, type of stand (broad-leaved or coniferous trees) and type of soil. Sampling classes were then compared and the variation factors were examined. Results demonstrated that nutrient stocks in the humus were not influenced by the cited factors and only the type of soil influenced nutrient stocks in soils. In fact, stocks of exchangeable elements in soils were much higher in colluviosols-Fluviosols which show redoximorphic characteristics, and available phosphorus stocks were lower than in Alocrisols-Neoluvisols. Moreover, a low variability of nutrient stocks was observed in Alocrisols-Neoluvisols as opposed to Colluviosols-Fluviosols, which may suggest the existence of other variation factors not taken into account in this study (hydromorphic gradient, type and age of stand in hydromorphic zones). DOI : 10.1051/forest:2007080 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 38

‐ 94 ‐  Natural attenuation on a field site contaminated with PAH and heavy metals: fate of polluants and their  toxicity, plant growth and microbial functional diversity  Leyval; Beguiristain; Biache; Cebron; Faure; Masfaraud; Norini; Ouvrard; Vasseur  CONSOIL 2008: THEME E ‐ REMEDIATION CONCEPTS & TECHNOLOGIES, VOLS 1‐3 (2008) , 161‐162 

  Abstract: DOI :  

 

  ‐ 95 ‐  Magnetic compensation of the gravity by using superconducting axisymmetric coils : spherical harmonics  method  Lorin, C; Mailfert, A  8TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'07) (2008) 97, ‐ 

  Abstract: An important work for space research is to study in weightless conditions (microgravity) the behavior of fluids such as liquid oxygen and liquid hydrogen1,2. In addition some magnetic ground-based stations allow to compensate the gravity and to meet space conditions since 19913. The magnetic devices in order to simulate micro-gravity allow low-cost experiments with unlimited time. The issue of the present techniques is to reach the same or better conditions (residual acceleration of the studied fluid) than the ones during the parabolic flights. In this paper, several specific distributions of the magnetic field are determined. These distributions allow to compensate the gravity by means of axisymmetric coils (solenoids). This paper introduces several distributions of the residual forces useful for different kinds of microgravity experiments. DOI :  

 

  ‐ 96 ‐  Magnetic levitation in two‐dimensional geometry with translational invariance  Lorin, C; Mailfert, A  JOURNAL OF APPLIED PHYSICS (2008) 104, ‐ 

  Abstract: The development of activities in space and of the corresponding technologies requires research on the behavior of both matter and biological organisms under weightless conditions. Various methods have been invented in order to simulate weightlessness, for example, drop towers, sounding rockets, or parabolic flights. Magnetic field ground-based devices have also been developed. This paper introduces an optimization method of the magnetic field so as to obtain magnetic levitation in a two-dimensional cylindrical geometry. DOI : 10.1063/1.3000633 

 

  ‐ 97 ‐  Use of principal component analysis to profile temporal and spatial variations of chlorinated solvent  concentration in groundwater  Lucas, L; Jauzein, M  ENVIRONMENTAL POLLUTION (2008) 151, 205‐212 

  Abstract: This work aims at evaluating spatial distribution patterns of concentration variations for chlorinated solvents in groundwater, based on principal component analysis and geographic information system (GIS) tools. The study investigates long-time series of chlorinated solvent concentrations in groundwater measured for 18 contaminated industrial sites. The characterization of contaminant plumes and delineation of pollutant sources are essential for choosing appropriate monitoring and remediation strategies, as contaminated groundwaters are characterized by complex patterns of spatial and temporal concentration variability, with wide unpredictable fluctuations over time. The present work describes the results of a new exploratory statistical method called the Variability Index Method (VIM) applied to environmental data to assess the perfomance of using concentration variations as molecular tracers to reveal aquifer dynamics, industrial impacts, and point sources for contamination plumes. The application of this method provides a useful assessment of controls over contaminant concentration variations as well as support for remediation techniques. (C) 2007 Elsevier Ltd. All rights reserved. DOI : 10.1016/j.envpol.2007.01.054 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 39

‐ 98 ‐  The impact of instability appearance on the quadratic law for flow through porous media  Lucas, Y; Panfilov, M; Bues, M  TRANSPORT IN POROUS MEDIA (2008) 71, 99‐113 

  Abstract: In the present paper, we attempt to explain the macroscopic flow law evolution in porous media according to the Reynolds number. A crenellated channel, considered as an element of such a medium, is used to perform numerical simulations in stationary and non-stationary cases. In the case of non-stationary laminar flows, we point out flow instabilities occurring in the channel at high Reynolds numbers and we focus on their influence on the macroscopic law. We qualitatively prove that they generate an additional quadratic contribution to Forchheimer's law. We use two methods to study this contribution: first, a periodic disturbance, for which the instabilities appearing at the beginning of disturbance become regular oscillations; then a pulse disturbance of the entry velocity field which enables us to link the additional quadratic contribution to the existence of an accumulation of fluid at low velocity in the channel. DOI : 10.1007/s11242-007-9113-8 

 

  ‐ 99 ‐  Chronic copper exposure and fatty acid composition of the amphipod Dikerogammarus villosus: Results from a  field study  Maazouzi, C; Masson, G; Izquierdo, MS; Pihan, JC  ENVIRONMENTAL POLLUTION (2008) 156, 221‐226 

  Abstract: Field study allows assessment of long-term effects on fatty acid (FA) composition of organisms under chronic exposure to metals. One expected effect of copper is peroxidation of lipids and essentially polyunsaturated fatty acids (PUFA). FA analysis was established for the amphipod Dikerogammarus villosus subjected to different degrees of copper exposure (4-40 mu g Cu L-1). A previous study in our team showed that this species regulates its body Cu concentration (106-135 mg Cu kg(-1) dry weight). Despite the high capacity of bioaccumulation, the absence of a correlation between copper concentration in D. villosus and water prevents its use as bioindicator of copper pollution. Both sexes from the most polluted site showed the lowest total FA content, but the highest PUFA percent, mainly of the long-chained variety (C20C22). Mechanisms leading to the prevention of lipid peroxidation in this species were discussed (metallothioneins and intracellular granules) and proposed with support from literature data. (c) 2007 Elsevier Ltd. All rights reserved. DOI : 10.1016/j.envpol.2007.12.010 

 

  ‐ 100 ‐  Midsummer heat wave effects on lacustrine plankton: Variation of assemblage structure and fatty acid  composition  Maazouzi, C; Masson, G; Izquierdo, MS; Pihan, JC  JOURNAL OF THERMAL BIOLOGY (2008) 33, 287‐296 

  Abstract: The effects of the 2003 European heat wave on a freshwater plankton assemblage and its fatty acid (FA) composition were investigated. Composition and FA profiles of four size categories of planktonic organisms collected in 2003 were compared to those of the colder year 2002. Temperature affected plankton population selecting thermophilic ones and had direct and indirect effects on its nutritional quality given by its FA patterns. Among algae, Ceratium hirundinella dominated and occurred at higher temperatures than described in the literature. Cyanobacteria showed a limited development. Diaphanosoma brachyurum was the dominant zooplanktonic species. Thermal environment appeared to favour the dominance of cladocerans and a decline in copepods abundance with cyclopoids (Acanthocyclops robustus) favoured over calanoids. Variation of FA composition with temperature was reflected in the relative proportion of saturated FA (SAFA), monounsaturated FA (MUFA) and polyunsaturated FA (PUFA). Organism exposure to overheated water resulted in increased SAFA and MUFA content at the expense of PUFA.This effect can be promoted in phytoplankton with high light intensity and sunshine duration. (c) 2008 Elsevier Ltd. All rights reserved. DOI : 10.1016/j.jtherbio.2008.03.002 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 40

‐ 101 ‐  Parameter sensitivity analysis for a Drucker‐Prager model following from numerical simulations of indentation  tests  Magnenet, V; Giraud, A; Homand, F  COMPUTATIONAL MATERIALS SCIENCE (2008) 44, 385‐391 

  Abstract: A parameter sensitivity analysis is carried out from numerical simulations of indention tests. The indented material obeys a simple Drucker-Prager behavior with no hardening rule, involving four material properties. For each of the parameters, the sensitivity is defined as the variation of the error function around a reference indentation curve. It is computed for three loading paths and five indenter shapes: spherical, conical, cylindrical, tetrahedral, and pyramidal. Finally, each of the sensitivities are compared with each other and commented on. (C) 2008 Elsevier B.V. All rights reserved. DOI : 10.1016/j.commatsci.2008.03.042 

 

  ‐ 102 ‐  Inelastic constitutive relations for foamed materials: A statistical approach and its application to open‐cell  melamine  Magnenet, V; Rahouadj, R; Bacher, P; Cunat, C  MECHANICS OF MATERIALS (2008) 40, 673‐684 

  Abstract: The aim of this study is to characterize the viscoelastic behavior at finite strain of a melamine foam submitted to multiple loading paths of uniaxial compression. The constitutive law is obtained by specializing a previously proposed model arising from an irreversible thermodynamic approach for several types of material (e.g. polymer, metal alloys) to include the essential microscopic features of this open-cell foam. The model is based on the central concept of relaxed state, which is defined as a thermodynamic state of metas table equilibrium including the strain history effect. In the case of the present material, it is shown that the corresponding relaxed stress may thus be formulated using the tools of statistical mechanics: namely, the Shannon entropy (S) is extremized under adequate geometric constraints. Thus, the Lagrange multipliers associated with these requirements are defined as forces conjugated to the degrees of freedom of the geometrical transformation. By comparing the predictions from the proposed inelastic constitutive model with experimental data for uniaxial compression interrupted by loading-unloading sequences, we conclude that the constitutive relations predict the mechanical behavior of the melamine foam. (c) 2008 Elsevier Ltd. All rights reserved. DOI : 10.1016/j.mechmat.2008.03.003 

 

  ‐ 103 ‐  Mobility of trace elements and oxygen in zircon during metamorphism: Consequences for geochemical tracing  Martin, LAJ; Duchene, S; Deloule, E; Vanderhaeghe, O  EARTH AND PLANETARY SCIENCE LETTERS (2008) 267, 161‐174 

  Abstract: This study addresses the mobility of the rare earth elements (REE), O, U and Pb during the formation of metamorphic zircon by overgrowth and coupled dissolution-reprecipitation. For this purpose, the texture and REE, delta O-18 and U-Pb compositions of zircon crystals from a metabasite, an anatectic granite and a metapelite sampled on Naxos Island (Greece) have been characterised. The behaviour of O and REE during the formation of the zircon metarnorphic domains shows that two end-members can be distinguished: (i) Closed (or partially closed) system behaviour for oxygen and trace elements in zircon formed by coupled dissolution-reprecipitation. Metamorphic domains partially preserve the textural and geochemical characteristics of the precursor zircon. Chemical or isotopic equilibrium between the metamorphic zircon and the matrix is not completely reached for all the elements. Such zircons have to be used with caution for geochemical tracing. When re-equilibration is not complete, the U-Pb system is also not completely reset and the metamorphic domains yield old, scattered ages. (ii) Open system behaviour for oxygen and trace elements in zircon formed by overgrowth. These metamorphic zircons do not show an inherited shape and are devoid of relic magmatic zoning. Their composition reflects growth in an open system at the scale of the zircon grain with the fluid phase and the surrounding minerals. Because equilibrium between the metamorphic zircon and the matrix was thus favoured, zircon crystallisation can be more confidently related to the P-T history and fluid circulation events by geochemical tracing. (C) 2007 Elsevier B.V. All rights reserved. DOI : 10.1016/j.epsl.2007.11.029 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 41

‐ 104 ‐  Helium and neon abundances and compositions in cometary matter  Marty, B; Palma, RL; Pepin, RO; Zimmermann, L; Schlutter, DJ; Burnard, PG; Westphal, AJ; Snead, CJ; Bajt, S;  Becker, RH; Simones, JE  SCIENCE (2008) 319, 75‐78 

  Abstract: Materials trapped and preserved in comets date from the earliest history of the solar system. Particles captured by the Stardust spacecraft from comet 81P/Wild2 are indisputable cometary matter available for laboratory study. Here we report measurements of noble gases in Stardust material. Neon isotope ratios are within the range observed in "phase Q," a ubiquitous, primitive organic carrier of noble gases in meteorites. Helium displays He-3/He-4 ratios twice those in phase Q and in Jupiter's atmosphere. Abundances per gram are surprisingly large, suggesting implantation by ion irradiation. The gases are probably carried in high- temperature igneous grains similar to particles found in other Stardust studies. Collectively, the evidence points to gas acquisition in a hot, high ion- flux nebular environment close to the young Sun. DOI : 10.1126/science.1148001 

 

  ‐ 105 ‐  Control of alkali‐metal oxide activity in molten silicates  Mathieu, R; Khedim, H; Libourel, G; Podor, R; Tissandier, L; Deloule, E; Faure, F; Rapin, C; Vilasi, M  JOURNAL OF NON‐CRYSTALLINE SOLIDS (2008) 354, 5079‐5083 

  Abstract: A new thermochemical reactor is designed to control alkali-metal oxide activity simultaneously in several molten silicates at temperature Up to 1400 degrees C. The method consists in imposing an alkali metal vapor pressure in a closed system by Na-(g) evaporation from Na2O-xSiO(2) melt and equilibrating this vapor with the molten silicate samples. By comparison of experiments carried out in regular furnaces, the drastic reduction of the working volume ensures a better control of sodium metal vapor pressure for durations of the order of a hundred of hours. This device has been applied to measuring the sodium solubility and sodium-metal oxide activity at 1350 degrees C in the anorthite-diopside eutectic melt composition of the CaO-MgO-Al2O3-SiO2 system. system. (C) 2008 Elsevier B.V. All rights reserved. DOI : 10.1016/j.jnoncrysol.2008.07.004 

 

  ‐ 106 ‐  The Meso‐Cenozoic thermo‐tectonic evolution of the Eastern Pyrenees: an Ar‐40/Ar‐39 fission track and (U‐ Th)/He thermochronological study of the Canigou and Mont‐Louis massifs  Maurel, O; Monie, P; Pik, R; Arnaud, N; Brunel, M; Jolivet, M  INTERNATIONAL JOURNAL OF EARTH SCIENCES (2008) 97, 565‐584 

  Abstract: Vertical displacements on the SW-NE T (e) over capt fault (Eastern Pyrenees Axial Zone, France), which separates the Variscan Canigou-Caranca and Mont-Louis massifs, were constrained using a thermochronologic multi-method approach. Ar-40/Ar-39 data from the granitic Mont-Louis massif record its Variscan cooling history and reveal no ages younger than Early Cretaceous, while the Canigou-Caranca gneiss massif records systematically younger Ar-40/Ar-39 ages. These younger Ar-40/Ar-39 ages in the Canigou-Caranca gneiss massif are the result of partial to total rejuvenation of argon isotopic systems related to a thermal flow coeval with the Cretaceous HT-BP metamorphism in the North Pyrenean Zone. Only the deepest rocks from the Canigou-Caranca suffered this extensive Mid-Cretaceous thermal overprint probably due to differential burial around 4 km at that time. The post Mid-Cretaceous vertical displacements along the T (e) over capt fault are recorded by "low" temperature thermochronology using K-feldspar Ar-40/Ar-39, zircon and apatite fission track and (UTh)/He datings. The Mont-Louis granite samples experienced a long period of protracted cooling reflecting a lack of thermotectonic activity in this area from Late Palaeozoic to Early Cenozoic, followed by cooling from 55-60 Ma to Late Eocene at a mean rate of 15-20 degrees C/Ma in the final stage. This cooling stage corresponds to T (e) over capt fault reactivation with a reversed component, promoting exhumation of the Mont-Louis roof zone contemporaneously with the south-vergent Pyrenean thrusting. In the Canigou-Caranca massif, the main cooling event occurred from 32 to 18 Ma at a maximum rate of 30 degrees C/Ma during Early Oligocene followed by a more moderate rate of 3 degrees C/Ma from Late Oligocene to Early Burdigalian, coeval with the normal reactivation of the T (e) over capt fault in brittle conditions that accommodated the final exhumation of the massif during the opening of the Gulf of Lion. DOI : 10.1007/s00531-007-0179-x 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 42

‐ 107 ‐  An acanthocephalan parasite boosts the escape performance of its intermediate host facing non‐host  predators  Medoc, V; Beisel, JN  PARASITOLOGY (2008) 135, 977‐984 

  Abstract: Among the potential effects of parasitism on host condition, the 'increased host abilities' hypothesis is a counterintuitive pattern which might be predicted in complex-life-cycle parasites. In the case of trophic transmission, a parasite increasing its intermediate host's performance facing non-host predators improves its probability of transmission to an adequate, definitive host. In the present study, We investigated the cost of infection with the acanthocephalan polymorphus minutus oil the locomotor/escape performance of its intermediate host, the crustacean Gammarus roeseli. This parasite alters the behaviour of its intermediate host making it more vulnerable to predation by avian definitive hosts. We assessed the swimming speeds of gammarids using a stressful treatment and their escape abilities under predation pressure. Despite the encystment of P. minutus in the abdomen of its intermediate host, infected amphipods had significantly higher swimming speeds than uninfected ones (increases of up to 35%). Furthermore, when interacting with, the non-host Crustacean predator Dike rogammarus villosus, the highest escape speeds and greatest distances covered by invertebrates were observed for parasitized animals. The altered behaviour observed among the manipulated invertebrates supported the 'increased host abilities' hypothesis, which has until now remained untested experimentally. The tactic of increasing the ability of infected intermediate hosts to evade potential predation attempts by non-host species is discussed. DOI : 10.1017/S0031182008004447 

 

  ‐ 108 ‐  The basement of Calabria (Southern Italy) within the context of the Southern European Variscides: LA‐ICPMS  and SIMS U‐Pb zircon study  Micheletti, F; Fornelli, A; Piccarreta, G; Barbey, P; Tlepolo, M  LITHOS (2008) 104, 1‐11 

  Abstract: U-Pb spot zircon ages from metagabbros and rnetasediments of the Variscan lower crust in the Serre massif (southern Calabria) have been determined using LA-ICPMS and SIMS. The results, together with the literature data deriving from conventional and spot zircon ages and front Rb-Sr whole-rock isochrons, allow the geological history of the crustal block to be more tightly constrained from the Late Neoproterozoic to the Triassic, with particular emphasis on Variscan evolution. In a peri-Gondwana Pan-African/Cadomian basement, preserving memory of recycled older terrains with West African Craton affinities, mafic and felsic magmas emplaced at ca. 584 Ma (protoliths of metagabbros) and in the range 575537 Ma (protoliths of felsic orthogneisses). Partially or completely recrystallized domains of zircons from metaigneous rocks yield ages ranging from 500 to 440 Ma. These ages (consistent with those of recrystallized cores of magmatic zircon from felsic orthogneisses and with Rb-Sr isochron data for the lower crust metasediments) suggest tectonothermal Ordovician activity, which is likely to be connected to the opening of Palaeozoic basin(s) separating the future Variscan blocks from Gondwana. Most zircon ages in the metasediments cluster in the 340-260 Ma range, which probably corresponds to two major events: (i) crustal thickening between 340 and 300 Ma (Barrowian metamorphic event) and (ii) lower-P/high-T metamorphism, Bt-dehydration inching, crustal extension between 300 and 260 Ma. Triassic ages ranging from 249 4 Ma to 231 5 Ma, together with whole-rock Rb-Sr isochron age at 234 Ma for the lowermost metapelites of the section, Suggest tectonothermal activity, which prepared the opening of the Jurassic Neotethys. Similarities and differences relative to some circum-Mediterranean Variscan lower crust sections are also discussed, which contribute to the knowledge of south European Variscides evolution. (C) 2007 Elsevier B.V. All rights reserved. DOI : 10.1016/j.lithos.2007.11.003 

 

  ‐ 109 ‐  Sol/gel and isotropic/nematic transitions in aqueous suspensions of natural nontronite clay. Influence of  particle anisotropy. 1. Features of the I/N transition  Michot, LJ; Bihannic, I; Maddi, S; Baravian, C; Levitz, P; Davidson, P  LANGMUIR (2008) 24, 3127‐3139 

  Abstract: The phase behavior of a natural nontronite clay was studied for size-selected particles by combining osmotic pressure measurements, visual observations under polarized light, and theological experiments. In parallel, the positional and orientational correlations of the particles were analyzed by small-angle X-ray scattering. Aqueous suspensions of nontronite exhibit a true isotropic/nematic (I/N) transition that occurs before the sol/gel transition, for ionic strengths below 10(-3) M/L. In this region of the phase diagrams, the system appears to be purely repulsive. The I/N transition shifts toward lower volume fractions for increasing particle anisotropy, and its position in the phase diagram agrees well with the theoretical predictions for platelets. SAXS measurements reveal the presence of characteristic interparticular distances in the isotropic, nematic, and gel phases. The swelling law (separation distance vs swelling law) exhibits two regimes. For high volume fractions, the swelling law is one-dimensional as in layered systems and reveals the presence of isolated platelets. At lower volume fraction, distances scale as phi(-1/3), indicating isotropic volumic swelling. Finally, the experimental osmotic pressure curves can be satisfactorily reproduced by considering the interparticle distances between two charged planes whose effective charge is around 10% of the structural charge. DOI : 10.1021/1a703506z 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 43

  ‐ 110 ‐  Real time evaluation of composition and structure of concanavalin A adsorbed on a polystyrene surface  Mielczarski, JA; Dong, J; Mielczarski, E  JOURNAL OF PHYSICAL CHEMISTRY B (2008) 112, 5228‐5237 

  Abstract: In situ qualitative and quantitative evaluations of adsorbed submonolayers and multilayers of the protein Concanavalin A (ConA) on a polystyrene surface were carried out by attenuated total reflection infrared spectroscopy. The influence of pH and adsorption time on the composition and structure of the adsorbed protein layers was investigated by comparison of the experimental spectra with simulated spectra of hypothetical multilayer systems with the assumed composition, thickness, and structure. This methodology allows the differentiation of observed spectral changes that result from pure optical effects, associated with the passing of an incident beam through the multilayer system, from the chemical and structural changes caused by physicochemical interactions of proteins with polymer surfaces. This represents significant progress since small variations in the band positions or intensities of amide I and amide II infrared absorbance bands have an important interpretation consequence. The applied methodology significantly reduces the misinterpretation of recorded spectra of protein layers and is rewarded by a deep insight of the structure and composition of the samples. The composition, structure, and kinetics of the adsorption of ConA and hydration level of the adsorbed layers were evaluated in detail. Competitive adsorption of bovine serum albumin on pre-adsorbed ConA layers also was investigated to characterize the ConA surface distribution. Parallel studies using X-ray photoelectron spectroscopy support the conclusions drawn from infrared spectroscopic investigations on ConA molecular distributions at the polymer surface. Two-step models that describe ConA submonolayer formation at pH 4.8 and multilayer formation at pH 7.8 are proposed. DOI : 10.1021/jp076794m 

 

  ‐ 111 ‐  Study of archaeological artefacts to refine the model of iron long‐term indoor atmospheric corrosion  Monnier, J; Legrand, L; Bellot‐Gurlet, L; Foy, E; Reguer, S; Rocca, E; Dillmann, P; Neff, D; Mirambet, F; Perrin, S;  Guillot, I  JOURNAL OF NUCLEAR MATERIALS (2008) 379, 105‐111 

  Abstract: The study of long-term indoor atmospheric corrosion is involved in the field of the interim storage of nuclear wastes. Indeed study of archaeological artefacts is one of the only mean to gather information on very long periods. Concerning ancient items, due to the complexity of the system, it is necessary to couple many analytical techniques from the macro to the microscopic scale. This enables to propose a description of the Amiens cathedral chain rust layers, made of a matrix of goethite, with lepidocrocite and akaganeite locally present and marbling of a poor crystallized phase associated to ferrihydrite. Electrochemical measurements permit to study the reduction capacity of the rust layer and to draw reduction mechanisms of the so-called active phases, by in situ experiments coupled with X-ray diffraction and X-ray absorption spectroscopy. (C) 2008 Elsevier B.V. All rights reserved. DOI : 10.1016/j.jnucmat.2008.06.008 

 

  ‐ 112 ‐  Identification of nickel chelators in three hyperaccumulating plants: An X‐ray spectroscopic study  Montarges‐Pelletier, E; Chardot, V; Echevarria, G; Michot, LJ; Bauer, A; Morel, JL  PHYTOCHEMISTRY (2008) 69, 1695‐1709 

  Abstract: We have investigated the accumulation of nickel in a hyperaccumulating plant from the Brassicacae family Leptoplax emarginata (Boiss.) O.E. Schulz. Two supplementary hyperaccumulating plants, which have been the subject of a high number of publications, Alyssum murale Waldst. & Kit and Thlaspi caerulescens J.&C. Presl, and a nonaccumulating species Aurinia saxatilis were also studied for reference. The plants were grown during 4 months in specific rhizoboxes with Ni-bearing minerals as a source of nickel. Nickel speciation was analyzed through X-ray absorption spectroscopy at Ni Kedge (X-ray absorption near edge spectroscopy and extended X-ray absorption fine structure spectroscopy) in the different parts of the plants (leaves, stems and roots) and compared with aqueous solutions containing different organo-Ni(II) complexes. Carboxylic acids (citrate, malate) appeared as the main ligands responsible of nickel transfer within those plants. Citrate was found as the predominant ligand for Ni in stems of Leptoplax and Alyssum, whereas in leaves of the three plants, malate appeared as the chelating organic acid of accumulated metal. Histidine could not be detected either in leaves, stems nor roots of any studied plant sample. (C) 2008 Elsevier Ltd. All rights reserved. DOI : 10.1016/j.phytochem.2008.02.009 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 44

‐ 113 ‐  Mid‐infrared spectroscopy of refractory inclusions (CAIs) in CV and CO chondrites  Morloki, A; Kohler, M; Grady, MM  METEORITICS & PLANETARY SCIENCE (2008) 43, 1147‐1160 

  Abstract: We present laboratory mid-infrared absorption spectra (2.5 mu m to 16.0 mu m) of powdered calcium-aluminumrich inclusions (CAIs) and matrix separated from the carbonaceous chondrites Allende (CV3.2), Vigarano (CV3.3), and Ornans (CO3.3). Two groups of spectra with different features were found for the CAI: in the first group spectra are dominated by spinel, pyroxene, and socialite +/- nepheline, where main features occur at 9.3 mu m, 10.3 mu m, and 11.3 mu m. In the second group, characteristic minerals are spinel and melilite with typical band maxima at 11.0 mu m and 12.3 mu m, and a broad feature between 14.0 mu m and 15.0 mu m. The position of the broad spinel feature probably depends on its iron content. Comparison of band positions in spectra froth the CAI components to observed circumstellar emission spectra indicates the potential occurrence of CAI-like material. Pyroxene- and spinel-rich features could occur in spectra of dust around the Herbig Ae star HD104237, the T Tauri star Hen3-600 and the post-AGB star R Sge. Melilite- and spinel-rich components possibly appear in the spectrum of HD 104237, Hen3-600, 04187_1927, R Sge, and the planetary nebula Hb 12. There is also indication for a spinel component in dust from the Herbig Ae/Be star HD179218. The spectra of the AGB stars R Cas and theta Aps show no features of CAI-type spinel. DOI :  

 

  ‐ 114 ‐  THE LOW DIAPENSIA LAPPONICA HEATHLAND OF SAINT‐PIERRE AND MIQUELON ARCHIPELAGO; ITS  BIOLOGICAL SIGNIFICANCE  Muller, S  REVUE D ECOLOGIE‐LA TERRE ET LA VIE (2008) 63, 391‐396 

  Abstract: The low Diaperisia lapponica heathland of Saint-Pierre and Miquelon Archipelago, its biogeographical significance -The summits of Saint-Pierre and Miquelon archipelago are colonized by a plant community of open low heathland, whose plant composition shows a high concentration of ano-chamaephytes with arctic-alpine distribution, such its Arctostaphylos alpina, Diapensia Iapponica Loiseleuria procumbens and Salty uva-ursi. 'This Plant community can be classified in the achionophitic alliance Loiselcurio-Diapension. which is a typical unit of arctic tundra (Alaska, Labrador. Greenland. Iceland, Lapland. northern Siberia), In more southern areas dominated by boreal or temperate forests. this Unit Occurs oil high summits (for instance Mounts Otish in the Laurentides, Mounts Chic-Chocs in Gasp sic, Mount, S Washington in New Hampshire), where it characterizes all alpine tundra habitat. The occurrence oil the summits of Saint-Pierre and Miquelon archipelago of this Diapensia lapponica and Loiseleuria procumbens community assesses their natural asylvatic character during the postglacial peroid. It Constitute,; an arctic-alpine tundra community, which surmounts the boreal forest with Abies balsamea. This remarkable altitudinal zonation expresses the transition character of the archipelago vegetation between boreal and arctic bioclimatic areas. DOI :  

 

  ‐ 115 ‐  Biosorption study in a mining wastewater reservoir  Naja, G; Mustin, C; Volesky, B; Berthelin, J  INTERNATIONAL JOURNAL OF ENVIRONMENT AND POLLUTION (2008) 34, 14‐27 

  Abstract: An in situ sorption was conducted to assess the behaviour of cations in a mining wastewater reservoir. Sorption experiments on test materials showed that biomass mainly bound uranium, copper, lead, zinc, and nickel, whereas goethite bound arsenic and chromium. Clay minerals bound both barium and rare earth elements. The lacustrine sediments mainly contained iron oxy-hydroxides. Desorption experiments using potentiometric titration were conducted to investigate the effect of pH variations on the stability of the test sorbents after immersion in the lake. Results indicated the presence of weak to very weak acidic functional groups in the sediments attributed to their high content of organic matter affecting the mobility and the behaviour of metals in the lake deposits. DOI :  

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 45

‐ 116 ‐  The Paleogene record of Himalayan erosion: Bengal Basin, Bangladesh  Najman, Y; Bickle, M; BouDagher‐Fadel, M; Carter, A; Garzanti, E; Paul, M; Wijbrans, J; Willett, E; Oliver, G;  Parrish, R; Akhter, SH; Allen, R; Ando, S; Chisty, E; Reisberg, L; Vezzoli, G  EARTH AND PLANETARY SCIENCE LETTERS (2008) 273, 1‐14 

  Abstract: A knowledge of Himalayan erosion history is critical to understanding crustal deformation processes, and the proposed link between the orogen's erosion and changes in both global climate and ocean geochemistry. The most commonly quoted age of India-Asia collision is similar to 50 Ma, yet the record of Paleogene Himalayan erosion is scant - either absent or of low age resolution. We apply biostratigraphic, petrographic, geochemical, isotopic and seismic techniques to Paleogene rocks of the Bengal Basin, Bangladesh, of previously disputed age and provenance. Our data show that the first major input of sands into the basin, in the > 1 km thick deltaic Barail Formation, occurred at 38 Ma. Our biostratigraphic and isotopic mineral ages date the Barail Formation as spanning late Eocene to early Miocene and the provenance data are consistent with its derivation from the Himalaya, but inconsistent with Indian cratonic or Burman margin sources. Detrital mineral lag times show that exhumation of the orogen was rapid by 38 Ma. The identification of sediments shed from the rapidly exhuming southern flanks of the eastern-central Himalaya at 38 Ma, provides a well dated accessible sediment record 17 Myr older than the previously described 21 Ma sediments, in the foreland basin in Nepal. Discovery of Himalayan detritus in the Bengal Basin from 38 Ma: I) resolves the puzzling discrepancy between the lack of erosional evidence for Paleogene crustal thickening that is recorded in the hinterland; 2) invalidates those previously proposed evidences of diachronous collision which were based on the tenet that Himalayan-derived sediments were deposited earlier in the west than the east; 3) enables models of Himalayan exhumation (e.g. by mid crustal channel flow) to be revised to reflect vigorous erosion and rapid exhumation by 38 Ma, and 4) provides evidence that rapid erosion in the Himalaya was coincident with the marked rise in marine Sr-87/Sr-86 values since similar to 40 Ma. Whether 38 Ma represents the actual initial onset of vigorous erosion from the southern flanks of the east-central Himalaya, or whether older material was deposited elsewhere, remains an open question. (C) 2008 Elsevier B.V. All rights reserved. DOI : 10.1016/j.epsl.2008.04.028 

 

  ‐ 117 ‐  Variable weathering response of granite in tropical zones. Example of two sequences studied in Cameroon  (Central Africa)  Nguetnkam, JP; Kamga, R; Villieras, F; Ekodeck, GE; Yvon, J  COMPTES RENDUS GEOSCIENCE (2008) 340, 451‐461 

  Abstract: Two weathering sequences of granite, developed in two bioclimatic zones of Cameroon, have been studied by means of macroscopic and microscopic analyses, X-ray diffraction (XRD), chemical analyses, along with SEM and TEM observations. In the tropical rainforest of South Cameroon, characterized by half-orange hills, steep slopes, and good drainage, the weathering of granite leads to the neoformation of kaolinite and the formation of ferrallitic soil, made up of four horizons that display an acid pH and a SiO2/Al2O3 ratio < 3. In the savannah tropical dry climate of the Extreme North, with lesser-grade slopes and slow water-flow conditions, the weathering of granite leads to the neoformation of beidellite and the formation of chromic vertisol made up of three horizons that display a basic pH and a SiO2/Al2O3 ratio > 3. These results emphasize the influence of climate and local factors on clay minerals and soil formation in the intertropical regions. DOI : 10.1016/j.crte.2008.02.002 

 

  ‐ 118 ‐  Assessing the bleaching capacity of some Cameroonian clays on vegetable oils  Nguetnkam, JP; Kamga, R; Villieras, F; Ekodeck, GE; Yvon, J  APPLIED CLAY SCIENCE (2008) 39, 113‐121 

  Abstract: Four Cameroonian clays, constituted mainly of smectites associated to minor amounts of kaolinite and quartz, have been used to bleach palm oil, cottonseed oil and maize germ oil. Kinetic studies show that the best temperature and contact time for optimum bleaching of vegetable oil varied with the type of oil; these are: 95 degrees C and 2.5 h for palm oil, 85 degrees C and 0.25 h for cottonseed oil, and 85 degrees C and 0.5 h for maize germ oil. The bleaching ability of natural clays was poor when compared with that of industrial adsorbents. Acid activation of Cameroonian clays with IN sulphuric acid solution increased tremendously their adsorptive capacity, which therefore matches those of the industrial adsorbents. Further increase of the concentration of the acid solution used for clay activation did not induce a noticeable increase in the bleaching power of the adsorbents. This was attributed to the fact that the increase in the surface area is due to the fori-nation of silica but the surface area of H-clays remains almost constant over strong acid leaching and silica has very poor bleaching power of vegetable oils. FT-IR spectroscopy studies of the adsorbents after bleaching suggest strong interactions between the clays and adsorbent surface. Acid and iodine values of bleached oils reveal that oils are not deteriorated by clays during the bleaching process. The overall results lead to the conclusion that Cameroonian clays can be converted into potent adsorbents for bleaching vegetable oils. (C) 2007 Elsevier B.V. All rights reserved. DOI : 10.1016/j.clay.2007.05.002 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 46

‐ 119 ‐  Application of in situ cryogenic Raman spectroscopy to analyze synthetic fluid inclusions in the systems CaCl2‐ H2O and MgCl2‐H2O II: Phase transformation behaviour at lower temperatures  Ni, P; Ding, JY; Dubessy, J; Zhang, T  ACTA PETROLOGICA SINICA (2008) 24, 1968‐1974 

  Abstract: In situ cryogenic Raman spectra technique had been successfully used in studying the synthetic fluid inclusions of systems CaCl2-H2O and MgCl2-H2O. The combination of laser Raman microspectroscopy and microthermometry was applied to collect cryogenic Raman spectra on inclusions at different lower temperatures. This study shows that the different freezing methods, which depend on the salt content of inclusions, can be applied to collect effectively the Raman spectra. The salt kinds can be identified by the lower temperature Raman spectra of given salt hydrate and phase transformation behaviour can be record precisely by the systemic Raman spectra collecting. In situ cryogenic Raman spectra study on the synthetic inclusions laid the basis for the application of this technique to natural produced inclusions. It is believed that it will playing an irreplaceable role on the fluid inclusion research field in the future. DOI :  

 

  ‐ 120 ‐  Petrology of the Mio‐Pliocene volcanism to the North and East of Ngaoundere (Adamawa, Cameroon)  Nkouandou, OF; Ngounouno, I; Deruelle, B; Ohnenstetter, D; Montigny, R; Demaiffe, D  COMPTES RENDUS GEOSCIENCE (2008) 340, 28‐37 

  Abstract: Basaltic flows and thirty-five plugs of felsic alkaline volcanic rocks (phonolites and trachytes) of Mio-Pliocene age are exposed to the north and east of Ngaoundere (Adamawa, Cameroon). The series is composed of alkaline basalts, hawaiites, mugearites, benmoreites, phonolites, and trachytes. Despite the gap between basaltic and felsic lavas, major- and trace-element distributions are in favour of a co-magmatic origin for the whole series. The basalts are similar in their chemical and isotopic compositions (0.7031 < Sr-87/Sr-86)(i) < 0.7041; +2.2 < epsilon(Ndi) < +5.0) to basalts from the continental and oceanic sectors of the 'Cameroon Hot Line'. Peralkaline trachytes have a more radiogenic initial Sr isotopic composition (0.7064); they have probably been contaminated by crustal material. The Ngaoundere basalts may derive from 1 to 2% partial melting of an infra-lithospheric source of the FOZO type (79% primitive mantle +20% altered MORB +1% pelagic sediments) at similar to 80-km depth in the garnet stability field. DOI : 10.1016/j.crte.2007.10.012 

 

  ‐ 121 ‐  Physicochemical properties of talc ore from three deposits of Lamal Pougue area (Yaounde Pan‐African Belt,  Cameroon), in relation to industrial uses  Nkoumbou, C; Villieras, F; Njopwouo, D; Ngoune, CY; Barres, O; Pelletier, M; Razafitianamaharavo, A; Yvon, J  APPLIED CLAY SCIENCE (2008) 41, 113‐132 

  Abstract: Three talc deposits were discovered at Ngoung, Lamal POUgUe and Bibodi Lamal (Cameroon). They derived from ultramafic rocks and are enclosed in a Pan-African gamet and muscovite-bearing mica schist of the Yaounde series. The physico-chemical properties of these talc deposits have been investigated by different techniques including Scanning Electron and Transmission Microscopy (SEM and TEM), chemical analyses, X-ray diffraction (XRD), infrared spectroscopy, particle size analysis by laser diffraction and low temperature gas absorption-desorption. The mineralogical composition deduced from XRD is wide (talc+chlorite+tremolite +/- anthophyllite +/- chromite +/- serpentine +/- brucite +/- magnesite +/dolomite), but due to the high talc contents (approximate to 90%) the samples are close to monomineralic. SEM studies reveal that all talc deposits comprise bundles of platy talc and a few prismatic crystals of amphiboles and other contaminating minerals. Laser diffraction confirms the coarse particle size of the talc crystals. Mode values are as high as 105-170 mu m (except two samples displaying 76 and 42 mu m) and d50 ranges from 107 to 25 mu m. The values of specific surface area measured by BET and t-plot methods range from I to 6 m(2)/g and are correlated with external specific surface area measured by laser diffraction. Discrepancies from the trend are due to the semi-crystalline texture of the samples and mostly to intracrystalline structural defects revealed by TEM observations. In infrared spectra, specific absorption bands are distinguished for talc, chlorite, tremolite, carbonates, serpentine, brucite and water. Occasional substitutions in minerals led to a shift in some absorption bands. The chemical composition criteria important for most of the industrial applications such as ceramics and pharmaceutics are closely complied with in untreated samples from these deposits. In summary, high talc proportions, chemical compositions, platy morphology and coarse grain size of its crystals lead to the conclusion that the studied deposits are economically attractive. The data set of the present work is an important tool for choosing the beneficiation methods for specific applications. (C) 2007 Elsevier B.V. All rights reserved. DOI : 10.1016/j.clay.2007.10.006 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 47

‐ 122 ‐  Physicochemical properties of talc ore from Pout‐Kelle and Memel deposits (central Cameroon)  Nkoumbou, C; Villieras, F; Barres, O; Bihannic, I; Pelletier, M; Razafitianamaharavo, A; Metang, V; Ngoune, CY;  Njopwouo, D; Yvon, J  CLAY MINERALS (2008) 43, 317‐337 

  Abstract: Physicochemical properties of representative samples from talc deposits discovered at Pout-Kelle and Memel in Cameroon have been investigated using a variety of techniques. The data allow the study of the mineral crystal-chemistry, chemical and modal compositions, grain size distribution, textures and surface heterogeneity, and morphometric characteristics. As a result, we found that talc (platy or round, Fe-rich) prevails (165-90%) over Cr-chlorite (7-26%), halloysite, chromite, rutile, brucite and magnesite. Chemically, talc ores are made UP Of Si02, MgO, Fe203 and minor A1203- Mode values range from 50 to 55 prn at Memel and from 30 to 90 pin at Pout-Kelle. Specific surface areas measured by BET and t-plot methods range from 1.3 to 2.5 in 2/g. The large values of niorphometric ch aracteri sties are indicative of high crystallinity and platiness. Potential uses of these talc ores in the rubber, plastics and paper industries require beneficiation processes. Interestingly, the Memel deposit and most zones ofthe Pout-Kelle deposit are free of needle-shaped crystals, an advantage for environmental safety. DOI : 10.1180/claymin.2008.043.2.11 

 

  ‐ 123 ‐  Effective solution through the streamline technique and HT‐splitting for the 3D dynamic analysis of the  compositional flows in oil reservoirs  Oladyshkin, S; Royer, JJ; Panfilov, M  TRANSPORT IN POROUS MEDIA (2008) 74, 311‐329 

  Abstract: Streamline approach is often used as an alternative effective method to classical finite difference technique for solving large heterogeneous fluid flow models in petroleum reservoirs. In the case of complex multi-component fluid system, this approach is scarcely used because the hydrodynamic and thermodynamic flow equations are strongly coupled through nonindependent variables including the pressure, the saturation and the species concentrations. It has been shown recently (Oladyshkin and Panfilov, Two-phase flow with phase transitions in porous media: instability of stationary solutions and a semi-stationary model. Third Biot Conference on Poromechanics, Norman, Oklahoma, USA, 2005; Oladyshkin and Panfilov, Comptes Rendus Acad Sci Mecanique, Elsevier 335(1):7-12, 2007) that assuming quasi steady-state for the pressure field, the hydrodynamic and thermodynamic parts can be split into a set of equations that is referred as HT-split compositional model. In this work, the HT-split model is combined with the streamline technique. This approach has been implemented in gOcad using the StreamLab plug-in. The pressure field and the streamlines are computed using the finite volume flow simulator. The equations that govern the equilibrium between phases are solved separately using a classical nonlinear solver. A multi-component 1D solver has been implemented using the HT-split equations along the streamlines. Tools for visualizing the time evolution of species compositions have been also developed. Finally a simple case study illustrating the technique is presented. It is shown that the HT-splitting method coupled to the streamline technology provides an effective tool to solve complex problems involving multi-compositional flow for any 3D reservoir geometry and for any gas-liquid system. The advantage of such a technology is that the number of components is not limited. DOI : 10.1007/s11242-007-9197-1 

 

  ‐ 124 ‐  Stability of carbon nanotubes to laser irradiation probed by Raman spectroscopy  Olevik, D; Soldatov, AV; Dossot, M; Vigolo, B; Humbert, B; Mcrae, E  PHYSICA STATUS SOLIDI B‐BASIC SOLID STATE PHYSICS (2008) 245, 2212‐2215 

  Abstract: We report on a systematic study of the influence of laser irradiation on the Raman spectra of HiPco-produced single, wall CNTs. Specifically, we have examined the Raman response of bundled CNTs to: i) laser power density; ii) exposure time and iii) photon energy (1.96 and 2.33 eV). Our results show that irreversible destruction of CNTs in the bundles can occur at even low laser power density (0.15 kW/cm(2)). The tubes with smaller diameters are influenced first and the rate of CNT destruction increases with photon energy. Finally, we determined that when investigating destruction of CNT bundles, the use of a low laser power density is required because changes in the structure of the bundles can lead to sample temperature changes for otherwise identical measurement parameters. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim DOI : 10.1002/pssb.200879661 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 48

‐ 125 ‐  Inactivation of E‐coli mediated by high surface area CuO accelerated by light irradiation > 360 nm  Paschoalino, M; Guedes, NC; Jardim, W; Mieluarski, E; Mielczarski, JA; Bowen, P; Kiwi, J  JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A‐CHEMISTRY (2008) 199, 105‐111 

  Abstract: CuO powders with different specific surface areas are reported hereby to inactivate E. coli in aqueous solution in the dark under visible light irradiation lambda > 360 nm. The inactivation of E. coli mediated by the CuO suspensions was investigated as a function of the solution parameters: specific surface area of the Cu-oxides (40-77 m(2)/g), amount of CuO, light intensity and fare of the Cu1+-ion within the inactivation process. The specific surface area of the CuO was observed to play an important role during the E coli inactivation kinetics. The light induced inactivation of E coli in CuO suspensions (1 g/L) was complete within 4 h. The cytotoxicity of E. call when using CuO (77 m(2)/g) was found for CuO concentrations as low as 0.2 g/L. A reaction mechanism is suggested for the Fenton-like reactions due to the Cu-ions/CuO action and the reactive oxygen species (ROS) generated in solution. These highly oxidative radicals decompose Orange II and methylene blue (MB) dyes in aqueous solution of CuO. The CuO in contact with the bacterial suspension shows a change in its surface oxidation state from Cu2+ to Cu1+. The outermost layer of the catalyst (5-7 nm) becomes mainly Cu2O (80%) and CuO (20%) as observed by X-ray photoelectron spectroscopy (XPS). A shift of the Cu 2p(3/2) peak from the initial position at 933.6-932.6 eV upon contact of the E coli with CuO was observed concomitant with the disappearance of the Cu2+ shake-up satellite lines at 942.3 and 962.2 eV. The XPS surface composition of copper catalyst is reported at different stages of E. coli inactivation and it was observed that the reduced copper oxide remains stable during the 4 h needed to inactivate the E coli suspension. (C) 2008 Elsevier B.V. All rights reserved. DOI : 10.1016/j.jphotochem.2008.05.010 

 

  ‐ 126 ‐  The Variscan Tamlalt‐Menhouhou gold deposit, Eastern High‐Atlas, Morocco  Pelleter, E; Cheilletz, A; Gasquet, D; Mouttaqi, A; Annich, M; El Hakour, A; Feraud, G  JOURNAL OF AFRICAN EARTH SCIENCES (2008) 50, 204‐214 

  Abstract: The Tamlalt-Menhouhou gold deposit belongs to the Neoproterozoic Palaeozoic Tamlalt inlier located in the Eastern High-Atlas (Morocco). it occurs in altered Upper Neoproterozoic bimodal volcanic and volcano- sedimentary units outcropping in the Tamlalt-Menhouhou area. Gold mineralization has been identified in quartz veins related to shear-zones associated with a strong quartz-phyllic-argillic alteration. Visible free gold is related to goethite-malachite-barite boxworks in quartz veins. The other alteration minerals accompanying gold mineralization are mainly carbonates, chlorite, hematite, albite and pyrite whose relative proportion defines three alteration types. Ar-40/Ar-39 geochronology performed on phengite grains from phyllic alteration and the auriferous quartz veins, yields plateau ages ranging from 300 +/- 5 Ma to 284 +/- 12 Ma with a weighted mean age of 293 +/- 7 Ma. This identifies a Late Variscan age for the Tamlalt-Menhouhou "shear zones-related" gold deposit and emphasizes the consequences of the Variscan orogeny for gold mineralization in the High-Atlas and AntiAtlas Neoproterozoic inliers. (c) 2007 Elsevier Ltd. All rights reserved. DOI : 10.1016/j.jafrearsci.2007.09.008 

 

  ‐ 127 ‐  Equation of state taking into account dipolar interactions and association by hydrogen bonding: II ‐ Modelling  liquid‐vapour equilibria in the H2O‐H2S, H2O‐CH4 AND H2O‐CO2 systems  Perfetti, E; Thiery, R; Dubessy, J  CHEMICAL GEOLOGY (2008) 251, 50‐57 

  Abstract: The CPAMSA equation of state proposed in Perfetti et al. [Perfetti, E., Thiery, R., Dubessy, J., 2008-this issue. Modelling liquid-vapour equilibria with an equation of state taking into account dipolar interactions and association by hydrogen bonding. I-Application to water and hydrogen sulphide. Chem. Geol.](2008-this issue) results in a better reproduction of the thermodynamic properties of pure water and pure hydrogen sulphide than obtained using the classical CPA or SRK equations of state along the vapour-liquid equilibrium. It considers three contributions. The first contribution represents the reference Van der Waals fluid which is modelled by the SRK cubic ECS. The second contribution accounts for association through hydrogen bonding and is modelled by a term derived from Cubic Plus Association (CPA) theory. The third contribution corresponds to the dipolar interactions and is modelled by the Mean Spherical Approximation (MSA) theory. This present paper extends the CPAMSA equation of state for multi components systems, thus simple mixing rules between dipolar molecules are proposed to model the H2O-H2S binary system using a symmetrical approach. Binary interaction parameters which steps in the cubic terms (i.e. the Van der Waals mixing rule) are optimized on experimental solubility data of gas in aqueous solutions. Calculated phase equilibria in the H2O-H2S, H2O-CO2, H2O-CH4 systems reproduced the experimental data within 7% of average accuracy. Except for the H2C-CH4 system, binary interactions parameters estimated by fitting experimental data are closed to zero. (C) 2008 Elsevier B.V. All rights reserved. DOI : 10.1016/j.chemgeo.2008.02.012 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 49

‐ 128 ‐  Equation of state taking into account dipolar interactions and association by hydrogen bonding. I: Application  to pure water and hydrogen sulfide  Perfetti, E; Thiery, R; Dubessy, J  CHEMICAL GEOLOGY (2008) 251, 58‐66 

  Abstract: A new equation of state (EOS) is proposed to model liquid-vapor-equilibrium of pure components and water gases systems in geological conditions relevant to diagenesis, hydothermal systems, anchimetamorphism and acid gases storage. This new equation of state is based on Statistical Association Fluid Theory and Mean Spherical Approximation Theory and proposes to take into account the respective association by hydrogen bonding and dipolar interactions. The aim of this work was to add these dipolar interactions in addition of cubic and association contributions that were not ever done since typical CPA EOS only take account association by hydrogen bonding. This first paper is focused on the pure water and pure hydrogen sulfide. For pure H2S, the parameters, such as dipole moment and size of the molecule, are fitted to experimental data along the saturation curve. The accuracy of the model, both for saturation pressure and liquid density, is much better as compared to previous cubic EOS. For pure H2O system, the parameters are fitted along the saturation line of water. The accuracy is excellent along this coexistence curve for both saturation pressure and volumes of liquid and vapor. Parameters such as the energy of hydrogen bonding, dipolar moment and size of molecules are compatible with experimental data. In the temperature range of 25-400 degrees C and pressure range of 1-10,000 bar, the model predict satisfactorily the molar volume. This works opens the way to include other components such as gas and salts considering their energy contribution in the Helmholtz energy. (C) 2008 Elsevier B.V. All rights reserved. DOI : 10.1016/j.chemgeo.2008.02.010 

 

  ‐ 129 ‐  Effect of rhizosphere and plant‐related factors on the cadmium uptake by maize (Zea mays L.)  Perriguey, J; Sterckeman, T; Morel, JL  ENVIRONMENTAL AND EXPERIMENTAL BOTANY (2008) 63, 333‐341 

  Abstract: The characteristics of 12- and 24-day-old maize plants (Zea mays L. cv MB862) related to Cd absorption were investigated with respect to the influence of Cd concentration in the plant organs, to plant age, absorption time and competition with micronutrients. Despite high Cd concentrations in the nutrient solution, hydroponically cultivated maize did not seem to be affected by Cd toxicity, except for the highest Cd level (100 mu mol L-1). There was on average five times more Cd in roots than in shoots and the Cd root to shoot ratio increased with increasing Cd concentration in the nutrient solution. No significant differences were observed between influx measured for 2 h in the middle of the day light period and for a full day period. Plants with different internal Cd concentrations showed similar root absorption characteristics of this metal. The root Cd influxes were three times higher in solutions with low micronutrient contents than in the solutions with higher micronutrient contents, and almost three times higher in 12-day-old roots than in 24-day-old roots. The root Cd influx was linearly related to its concentration in the solution, showing no saturable component. Our results suggest a non-specific and unregulated transport of Cd into the maize root symplast. They also indicate a regulation of the Cd translocation from root to shoot, as well as dependence of parameters of Cd root absorption on plant and rhizosphere conditions which should be taken into account for Cd uptake modelling. (C) 2008 Elsevier B.V. All rights reserved. DOI : 10.1016/j.envexpbot.2007.12.014 

 

  ‐ 130 ‐  Evidence of a critical content in Fe(0) on FoCa7 bentonite reactivity at 80 degrees C  Perronnet, M; Jullien, M; Villieras, F; Raynal, J; Bonnin, D; Bruno, G  APPLIED CLAY SCIENCE (2008) 38, 187‐202 

  Abstract: In order to assess the evolution of the confinement properties of clay engineered barriers (EBS) when in contact with metallic canisters containing radioactive wastes, Fe(0)-bentonite interactions need to be assessed. "45 days-80 degrees C" tests were performed using powdered FoCa7 bentonite and metallic iron. Since one fundamental parameter may be the available quantity of Fe(0), a wide range of Iron/Clay mass ratios (I/C) from 0 to 1/3 is used. The confinement power of clay material results from the swelling properties and the retention capacity. Thus, the major criterion which is chosen to assess the evolution of the confinement properties in this study is the variation of Cation Exchange Capacity (CEC). In parallel, the physico-chemical evolution of bentonite is studied using XRD and EDS-TEM microanalyses. The evolution of the distribution of iron environments is obtained by Fe-57 Mossbauer spectroscopy. This study evidences that both kaolinite and smectite from the bentonite are altered into SiAlFe gels when in contact with Fe(0). These gels maturates into Fe-rich ditrioctahedral phyllosilicates, whose composition is bounded by the one of odinite and greenalite in a Fe-M+-4Si diagram when I/C=1/3. Most of all, it is evidenced that the reaction depends on the available quantity of Fe(0). When the I/C ratio is between 1/30 and 1/7.5, the exchange capacity of FoCa7 bentonite starts decreasing, the consumption of Fe(0) becomes significant, the alteration of smectites occurs and secondary oxides are formed. The crystallization of Fe-rich phyllosilicates is observable when I/C ratio is higher, from a threshold between 1/7.5 and 1/5. Above I/C=1/3.75, initial iron oxides are strongly consumed and participate in the incorporation of Fe2+ and Fe3+ in gels or new phyllosilicates octahedra. These experimental results were used as input data for the prediction of the long-term evolution of the EBS using Crunch reactiontransport model. (C) 2007 Elsevier B.V. All rights reserved. DOI : 10.1016/j.clay.2007.03.002 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 50

  ‐ 131 ‐  Tectonodynamics of fluid‐conducting structural elements and migration of radionuclides in massifs of  crystalline rocks  Petrov, VA; Lespinasse, M; Hammer, J  GEOLOGY OF ORE DEPOSITS (2008) 50, 89‐111 

  Abstract: The principal aspects of reconstruction of conditions and paths of fluid migration in massifs of crystalline rocks are considered. The spatiotemporal relationships between stress fields, brittle failure, and migration of radionuclides are discussed. The main attention is focused on the staged character of tectonic events, fluid circulation conditions, and the sequence of uranium mineral formation as determined with structural, geological, tectonophysical, petrophysical, petrographic, mineralogical and geochemical, microstructural, microthermometric, and radiographic methods. As is exemplified in uranium deposits and massifs of silicic igneous rocks, the comprehensive consideration of the tectonodynamics of fluid-conducting structural elements and radionuclide migration is necessary for providing insights into the localization and redistribution of uranium, the PT conditions of uranium ore formation, and the forecast for long-term safety of disposal of radioactive wastes in crystalline rocks. DOI : 10.1134/S1075701508020013 

 

  ‐ 132 ‐  Characterization for industrial applications of clays from Lembo deposit, Mount Bana (Cameroon)  Pialy, P; Nkoumbou, C; Villieras, F; Razafitianamaharavo, A; Barres, O; Pelletier, M; Ollivier, G; Bihannic, I;  Njopwouo, D; Yvon, J; Bonnet, JP  CLAY MINERALS (2008) 43, 415‐435 

  Abstract: The Lembo clay deposit occurs on orthogneiss, but it also comprises clays with litho-relicts of volcanic rocks. In this study, ten samples from two sites were investigate. The mineralogical compositions consisted of kaolinite + halloysite + illite + quartz + hematite + anatase +/- rutile +/- orthoclase +/- sanidine +/- magnetite +/- maghemite +/- goethite +/- Ba-AlFe-phosphates +/- carbonates +/- sulphates. Kaolinite-halloysite and quartz are the prevailing minerals. Some volcanic derived clays contain Fe-rich kaolinite-halloysite (9.6-14.1 wt.% Fe2O3). The chemical compositions, colours and specific surface area (SSA) measurements reveal two groups of clays: one with a positive whiteness index (1B), small SSA and small Fe content, and the other showing a large SSA, negative IB and relatively large Fe contents. The compositions of the first group are close to those of clays from the Mayouom deposit (Cameroon), and from some European commercial kaolins used in ceramics. Relatively Fe-rich clay materials may conform to most formulations of earthen bricks. As a whole, the Lembo clay deposit comprises various compositions of kaolinitie clays, which may yield the opportunity for extensive application in ceramics. DOI : 10.1180/claymin.2008.043.3.07 

 

  ‐ 133 ‐  Timing of East African Rift development in southern Ethiopia: Implication for mantle plume activity and  evolution of topography  Pik, R; Marty, B; Carignan, J; Yirgu, G; Ayalew, T  GEOLOGY (2008) 36, 167‐170 

  Abstract: Accurate determination of rifting chronology and associated uplift is crucial to understanding the evolution of the East African Rift System (EARS) and for identifying the significance of mantle plumes during continental breakup. This investigation of rift-related cooling along a major fault scarp in southern Ethiopia, using (U-Th)/He thermochronometry, shows that rifting started not before 20 Ma. Therefore, there is an absence of significant rift activity synchronous with the earliest volcanics of the EARS, which are Eocene in age. In contrast, this initial magmatic episode, which preceded the main flood basalts and rifting events by 15-20 Ma, is attributed to convective instabilities above the rising Afar mantle plume. A detailed spatial and temporal quantification of uplift and denudation along this rift shoulder shows that rift development in southern Ethiopia has been continuous since initiation in the Miocene. This direct evidence of denudation is inconsistent with the hypothesis that massive Plio-Pleistocene rifting and associated uplift occurred in this part of the EARS and could have triggered recent aridification. To the contrary, our study rather supports a major contribution of plume-related doming for creation of topographical barriers in the Ethiopian province. DOI : 10.1130/G24233A.1 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 51

‐ 134 ‐  Petroleum and aqueous inclusions from deeply buried reservoirs: Experimental simulations and consequences  for overpressure estimates  Pironon, J; Bourdet, J  GEOCHIMICA ET COSMOCHIMICA ACTA (2008) 72, 4916‐4928 

  Abstract: Synthetic hydrocarbon and aqueous inclusions have been created in the laboratory batch reactors in order to mimic inclusion formation or re-equilibration in deeply buried reservoirs. Inclusions were synthesized in quartz and calcite using pure water and Mexican dead oil, or n-tetradecane (C14H30), at a temperature and pressure of 150 degrees C and 1 kbar. One-phase hydrocarbon inclusions are frequently observed at standard laboratory conditions leading to homogenization temperatures between 0 and 60 degrees C. UV epifluorescence of Mexican oil inclusions is not uniform; blue and greenyellow colored inclusions coexist; however, no clear evidence of variations in fluid chemistry were observed. Homogenization temperatures were recorded and the maxima of T-h plotted on histograms are in good agreement with expected Th in a range of 6 degrees C. Broad histograms were reconstructed showing non-symmetrical Th distributions over a 20 degrees C temperature range centered on the expected Th. This histogram broadening is due to the fragility of the fluid inclusions that were created by re-filling of pre-existing microcavities. Such Th histograms are similar to Th histograms recorded on natural samples from deeply buried carbonate reservoirs. Th values lower than those expected were measured for hydrocarbon inclusions in quartz and calcite, and for aqueous inclusions in calcite. However, the results confirm the ability of fluid inclusions containing two immiscible fluids to lead to PT reconstructions, even in overpressured environments. (C) 2008 Elsevier Ltd. All rights reserved. DOI : 10.1016/j.gca.2008.07.019 

 

  ‐ 135 ‐  Perforative corrosion of pyrite enhanced by direct attachment of Acidithiobacillus ferrooxidans  Pisapia, C; Humbert, B; Chaussidon, M; Mustin, C  GEOMICROBIOLOGY JOURNAL (2008) 25, 261‐273 

  Abstract: This study aimed to determine the relationship between cell adhesion and pyrite corrosion. In order to determine cell adhesion rates, a new in vivo imaging procedure was developed with CLSM. Total bacteria coverage rates remained low ( 14%). Adsorption isotherms pointed out two types of cell adhesion sites. Bacteria adhered mainly to corrosion pittings walls with a higher affinity. They favour the formation of deep corrosion pits by maintaining short-range electronic circulations and they avoid surface passivation. This study completes the common model of bio-corrosion of pyrite and we propose to refine the direct/indirect model by proximal and distal approaches. DOI : 10.1080/01490450802258105 

 

 

Publications des Unités de recherche de la FR-EST (BEF, CRPG, G2R, LAEGO, LEM, LIEBE, LIMOS, LSE) -

Année 2008

- 52

‐ 136 ‐  Igneous layering, fractional crystallization and growth of granitic plutons: The Dolbel batholith in SW niger  Pupier, E; Barbey, P; Toplis, MJ; Bussy, F  JOURNAL OF PETROLOGY (2008) 49, 1043‐1068 

  Abstract: This study reassesses the development of compositional layering during the growth of granitic plutons, with emphasis on fractional crystallization and its interaction with both injection and inflation-related deformation. The Dolbel batholith (SW Niger) consists of 14, kilometre-sized plutons emplaced by pulsed magma inputs. Each pluton has a coarsegrained core and a peripheral layered series. Rocks consist of albite (An(