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See detailGeochemistry of cumulates from the Bjerkreim-Sokndal layered intrusion (S. Norway). Part I. Constraints from major elements on the mechanism of cumulate formation and on the jotunite liquid line of descent
Duchesne, Jean-Clair ULg; Charlier, Bernard ULg

in Lithos (2005), 83(3-4), 229-254

Whole-rock major element compositions are investigated in 99 cumulates from the Proterozoic Bjerkreim-Sokndal layered intrusion (Rogaland Anorthosite Province, SW Norway), which results from the ... [more ▼]

Whole-rock major element compositions are investigated in 99 cumulates from the Proterozoic Bjerkreim-Sokndal layered intrusion (Rogaland Anorthosite Province, SW Norway), which results from the crystallization of a jotunite (Fe-Ti-P-rich hypersthene monzodiorite) parental magma. The scattering of cumulate compositions covers three types of cumulates: (1) ilmenite-leuconorite with plagioclase, ilmenite and Ca-poor pyroxene as cumulus minerals, (2) magnetite-leuconorite with the same minerals plus magnetite, and (3) gabbronorite made up of plagioclase, Ca-poor and Ca-rich pyroxenes, ilmenite, Ti-magnetite and apatite. Each type of cumulate displays a linear trend in variation diagrams. One pole of the linear trends is represented by plagioclase, and the other by a mixture of the mafic minerals in constant proportion. The mafic minerals were not sorted during cumulate formation though they display large density differences. This suggests that crystal settling did not operate during cumulate formation, and that in situ crystallization with variable nucleation rate for plagioclase was the dominant formation mechanism. The trapped liquid fraction of the cumulate plays a negligible role for the cumulate major element composition. Each linear trend is a locus for the cotectic composition of the cumulates. This property permits reconstruction by graphical mass balance calculation of the first two stages of the liquid line of descent, starting from a primitive jotunite, the Tjorn, parental magma. Another type of cumulate, called jotunite cumulate and defined by the mineral association from the Transition Zone of the intrusion, has to be subtracted to simulate the most evolved part of the liquid line of descent. The proposed model demonstrates that average cumulate compositions represent cotectic compositions when the number of samples is large (> 40). The model, however, does not account for the K2O evolution, suggesting that the system was open to contamination by roof melts. The liquid line of descent corresponding to the Bjerkreim-Sokndal cumulates differs slightly from that obtained for jotunitic dykes in that the most Ti-, P- and Fe-rich melts (evolved jotunite) are lacking. The constant composition of the mafic poles during intervals where cryptic layering is conspicuous is explained by a compositional balance between the Fe-Ti oxide minerals. which decrease in Fe content in favour of Ti. and the pyroxenes which increase in Fe. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailGeochemistry of cumulates from the Bjerkreim-Sokndal layered intrusion (S. Norway). Part II. REE and the trapped liquid fraction
Charlier, Bernard ULg; Vander Auwera, Jacqueline ULg; Duchesne, Jean-Clair ULg

in Lithos (2005), 83(3-4), 255-276

Rare earth elements in bulk cumulates and in separated minerals (plagioclase, apatite, Ca-poor and Ca-rich pyroxenes, ilmenite and magnetite) from the Bjerkreim-Sokndal layered intrusion (Rogaland ... [more ▼]

Rare earth elements in bulk cumulates and in separated minerals (plagioclase, apatite, Ca-poor and Ca-rich pyroxenes, ilmenite and magnetite) from the Bjerkreim-Sokndal layered intrusion (Rogaland Anorthosite Province, SW Norway) are investigated to better define the proportion of trapped liquid and its influence on bulk cumulate composition. In leuconoritic rocks (made up of plagioclase, Ca-poor pyroxene, ilmenite, magnetite, olivine), where apatite is an intercumulus phase, even a small fraction of trapped liquid significantly affects the REE pattern of the bulk cumulate, together with cumulus minerals proportion and composition. Contrastingly, in gabbronoritic cumulates characterized by the presence of cumulus Ca-rich pyroxene and apatite, cumulus apatite buffers the REE content. La/Sm and Eu/Eu* VS. P2O2 variations in leuconorites display mixing trends between a pure adcumulate and the composition of the trapped liquid, assumed to be similar to the parental magma. Assessment of the trapped liquid fraction in leuconorites ranges from 2 to 25% and is systematically higher in the north-eastern part of the intrusion. The likely reason for this wide range of TLF is different cooling rates in different parts of the intrusion depending on the distance to the gneissic margins. The REE patterns of liquids in equilibrium with primitive cumulates are calculated with mass balance equations. Major elements modelling (Duchesne, J.C., Charlier, B., 2005. Geochemistry of cumulates from the Bjerkreiin-Sokndal layered intrusion (S. Norway): Part I. Constraints from major elements on the mechanism of cumulate formation and on the jotunite liquid line of descent. Lithos. 83, 299-254) permits calculation of the REE content of melt in equilibrium with gabbronorites. Partition coefficients for REE between cumulus minerals and a jotunitic liquid are then calculated. Calculated liquids from the most primitive cumulates are similar to a primitive jotunite representing the parental magma of the intrusion, taking into account the trapped liquid fraction calculated from the P2O5 content. Consistent results demonstrate the reliability of liquid compositions calculated from bulk cumulates and confirm the hypothesis that the trapped liquid has crystallized as a closed-system without subsequent mobility of REE in a migrating interstitial liquid. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailGeochemistry of granitoids from the south Carpathians: A review
Berza, Tudor; Andar, Petre; Tatu, Mihai et al

in Anuarul Institutului Geologic al României (2000), 71

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See detailGeochemistry of Upper Cretaceous high-K calc-alkaline post-collisional intrusions in the Banat Province (western south Carpathians, Romania)
Dupont, Alain; Vander Auwera, Jacqueline ULg; Pin, Christian et al

in Journal of Conference Abstracts (2001), 6

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See detailGeochemistry, Magnetic Susceptibility and Gamma Ray spectrometry records Across the Frasnian-Famennian boundary at Fuhe, China.
Da Silva, Anne-Christine ULg; Whalen, M; Sliwinski, M et al

in Geologica Belgica Meeting 2012; Moving plates and melting icecaps. Processes and forcing factors; Abstract book (2012)

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See detailA Geocodification for 3D objects terrestrial surveys
Kasprzyk, Jean-Paul ULg; Billen, Roland ULg

in Neutens, Tijs; De Ryck, Marijke; De Maeyer, Philippe (Eds.) Proceedings of the 4th International Workshop on 3D Geo-information (2009, November)

Nowadays, mean 3D data aquisition techniques are photogrammetry and laserscanning. Their advantage is the huge amount of points that can be measured in a very short time on the field. Nevertheless, the ... [more ▼]

Nowadays, mean 3D data aquisition techniques are photogrammetry and laserscanning. Their advantage is the huge amount of points that can be measured in a very short time on the field. Nevertheless, the post-processing associated to these techniques allowing to build a real 3D model from the clouds of points is very long. Therefore, we developed a geocodification ("field to finish") for the 3D data acquisition at a low and/or middle level of details. Despite each point is measured one by one with a total station, the user can gain a lot of time because of the almost-absence of post processing. This paper shows some of the developed techniques and tries to demonstrate the possible complementarity between geocodification, laserscanning and photogrammtry. [less ▲]

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See detailGeodesics on a supermanifold and projective equivalence of superconnections
Leuther, Thomas ULg; Radoux, Fabian ULg; Tuynman, Gijs

in Journal of Geometry & Physics (2013), 67

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See detailGéodésie : le système GPS
Warnant, René ULg

Learning material (2001)

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See detailGéodésie géométrique et astronomie de position
Warnant, René ULg

Learning material (2010)

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See detailGéodésie spatiale
Warnant, René ULg

Learning material (2011)

Detailed reference viewed: 71 (4 ULg)
See detailLa géodésie spatiale à l'Observatoire Royal de Belgique
Warnant, René ULg; Bruyninx, Carine

in Nouvelles de la Science et des Technologies (1995), 13(2/3/4), 29-31

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See detailGeodetic and cartographical standards applied in Belgium
Donnay, Jean-Paul ULg; Lambot, Philippe

in Van Hecke, Etienne (Ed.) A Concise Geography of Belgium (2012)

Definition of datum BD72 and GRS 80, and cartographic systems Belgian Lambert 1972 & Belgian Lambert 2008, now in use in Belgium

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See detailGeoelectrical investigations (DC) on a contaminated site during biostimulation: monitoring results and resolution analysis
Caterina, David ULg; Nguyen, Frédéric ULg

Conference (2012, January 12)

In Belgium, as in many other countries, relatively anarchic economical and industrial development of the past century has resulted in a significant number of contaminated sites. When one of these sites ... [more ▼]

In Belgium, as in many other countries, relatively anarchic economical and industrial development of the past century has resulted in a significant number of contaminated sites. When one of these sites poses a risk to human or ecosystem, measures need to be taken to clean it up. Among these measures, methods using in situ bioremediation are beginning to become more important because of their ease of implementation and their relatively low cost. However, it is often difficult to ensure their effectiveness except by carrying out extensive drilling and sampling, which can be long and expensive while offering only punctual information. Thus, it becomes necessary to use other techniques to overcome these shortcomings. Recently, an increasing interest is being born to use geophysical methods as tools for remediation monitoring. As part of our work, we conducted several electrical resistivity tomography campaigns on a bus station located in Bassenge (Belgium) which has undergone a contamination of hydrocarbons (gasoline) for several years and on which a biostimulation remediation device was set up in order to clean it up. The aim of our investigations was to study the electrical response of the contaminated area during the remediation phase and whether electrical resistivity tomography allowed to monitor its effectiveness. After a year of monitoring, the time lapse images obtained show a significant decrease of electrical resistivities (up to -40%) during biostimulation at the location of the main contaminant plume and an increase again of resistivities from the time the biostimulation was stopped. The electrical response during the biostimulation is in agreement with the models presented by several authors in the literature. The increase again of resistivities after the stimulation is however more surprising and can be explained by several physico-chemical (sorption-desorption processes) or biological (decrease of conductive biofilms) assumptions. The results obtained tend to suggest that it is possible to use electrical resistivity tomography as a tool for qualitative control during the remediation of a contaminated site. However, for a more quantitative use of resistivity models, it is important to assess their reliability through the use of resolution indicators. We therefore developed a methodology to address this issue based on the creation of synthetic models representing simplified cases of field resistivities and we applied it on our case study. The results obtained provided us important information about the reliable parts of the resistivity models. These findings may lead in the future to the development of mathematical models that can link quantitatively geophysical properties to the level of (de)contamination of a site. [less ▲]

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See detailGeoelectrical monitoring on a contaminated site during biostimulation
Caterina, David ULg; Nguyen, Frédéric ULg

Poster (2011, December 01)

In Belgium, as in many other countries, relatively anarchic economical and industrial development of the past century has resulted in a significant number of contaminated sites. When one of these sites ... [more ▼]

In Belgium, as in many other countries, relatively anarchic economical and industrial development of the past century has resulted in a significant number of contaminated sites. When one of these sites poses a risk to human or ecosystem, measures need to be taken to clean it up. Among these measures, methods using in situ bioremediation are beginning to become more important because of their ease of implementation and their relatively low cost. However, it is often difficult to ensure their effectiveness except by carrying out extensive drilling and sampling, which can be long and expensive while offering only punctual information. Thus it becomes necessary to use other techniques to overcome these shortcomings. Recently, an increasing interest is being born to use geophysical methods as tools for remediation monitoring. As part of our work, we conducted several electrical resistivity tomography campaigns on a site contaminated by LNAPLs (gasoline) on which a biostimulation remediation device was set up. The aim of our investigations was to study the electrical response of the contaminated area during the remediation phase and whether electrical resistivity tomography allowed to monitor its effectiveness. After a year of monitoring, the time lapse images obtained show a significant decrease of the electrical resistivity (up to -50%) at the location of the main contaminant plume. This particular response during the biostimulation, in agreement with the models presented by several authors in the literature, tends to suggest that it is possible to use electrical resistivity tomography as a tool for qualitative control during the remediation. These findings may also lead in the future to the development of models to estimate more quantitatively the level of (de)contamination of a site. [less ▲]

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See detailGeografia, storia e poetiche del fantastico.
Moreno, Paola ULg

in Revue Belge de Philologie et d'Histoire (1997)

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See detailUn géographe en campagne : voir, connaître, représenter et comprendre.
Chevigne, Claire; Schmitz, Serge ULg; Tresegnie, Jean Pierre

in Donnay, Jean-Paul (Ed.) Recherches de géographie humaine, Hommage au Professeur Charles Christians. (1996)

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See detailGeographic and genetic variation of olfactory communication in butterflies: the male sex pheromone of Bicyclus butterfly species
Bacquet, Paul; Brattström, O.; Wang, H. L. et al

in Abstract book (2010, December 17)

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See detailGeographic ecology of soil oribatid mites in deciduous forests
Wauthy, G.; Noti, M.-I.; Dufrêne, Marc ULg

in Pedobiologia (1989), 33(6), 399-416

On a broad, geographic scale (Belgium), soil oribatid mites show relatively simple patterns of spatial distribution and habitat use since 2 groups of species can be defined: "regionally specialist' (RS ... [more ▼]

On a broad, geographic scale (Belgium), soil oribatid mites show relatively simple patterns of spatial distribution and habitat use since 2 groups of species can be defined: "regionally specialist' (RS) species which are rare and restrict their humus type occupancy, and "regionally generalist' (RG) species with reverse attributes. In the locality studied, 7/31 RS species inhabited all or nearly all the stands sampled and used widely disjunctive categories of habitat resources taking into account vertical location within organic layers (litter or humus), humus type (mor or moder) and vegetation (climax or secondary) developed in the study site. Nevertheless, their overlap on these categories was lower on average than the one of the 20 RG species which did not change their patterns on both geographic scales. Some of the 34 other RG species narrowed their local distribution and showed a clear specialization on the habitat categories. To explain the local/regional variations of patterns, it is proposed to interpret the regional distribution shown by soil oribatid mites in terms of tolerance to environmental factors. Then, it is advocated, the role of biotic interactions in the local widening of habitat breadth shown by the RS as well as RG species, and to produce a local non-equilibrium assemblage. -from Authors [less ▲]

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See detailGeographic structure and potential ecological factors in Belgium
Dufrêne, Marc ULg; Legendre, P.

in Journal of Biogeography (1991), 18(3), 257-266

The available potential ecological factors have been scored in the form of presence/absence in Universal Transverse Mercator (UTM) squares in Belgium. A correspondence analysis shows a strong underlying ... [more ▼]

The available potential ecological factors have been scored in the form of presence/absence in Universal Transverse Mercator (UTM) squares in Belgium. A correspondence analysis shows a strong underlying gradient in the data set which induces an extraordinary horseshoe effect. This gradient follows closely the altitude component. Applying the k-means clustering method on UTM squares produced geographically compact groups which are largely hierarchically nested. This indicates strong regional trends in the ecological data set. As homogeneous groups may also be artefacts created by the clustering algorithms on a continuous gradient, the relevance of the borders between homogeneous areas is tested. In general, k-means borders correspond to the main breaking lines between adjacent UTM squares. They can be referred to as natural borders. -Authors [less ▲]

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See detailGeographical allozymes differentiation in wild Phaseolus lunatus L. and its implication for conservation and management of populations
Zoro Bi, I.; Baudoin, Jean-Pierre ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2007), 11(4), 287-297

Detailed reference viewed: 6 (2 ULg)