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See detailGeochemical and Pb isotopic investigations in peat bogs from Southern Chile: Identification of particles supplies and possible paleoclimate record
De Vleeschouwer, F.; Ibanez, M.; Mattielli, N. et al

in Geochimica et Cosmochimica Acta (2004), 68(11), 478-478

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See detailGeochemical and Pb isotopic investigations in peat bogs from Southern Chile: Identification of particles supplies and possible paleoclimate record
De Vleeschouwer, François ULg; Ibanez, M.; Mattielli, N. et al

in Geochimica et Cosmochimica Acta (2004), 68(11), 478-478

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See detailGeochemical and Pb isotopic signature of peaty sediments from central-south Chile: Identification of particle supplies over the Holocene
De Vleeschouwer, François ULg; Ibanez, Maud; Mattielli, Nadine et al

in Journal of the Chilean Chemical Society [=JCCS] (2008), 53(3), 1640-1649

Two cores from tephra rich peat soils of the Chilean Lake District were investigated for mineral source and potential anthropogenic impact using elemental geochemistry, including rare earth elements, and ... [more ▼]

Two cores from tephra rich peat soils of the Chilean Lake District were investigated for mineral source and potential anthropogenic impact using elemental geochemistry, including rare earth elements, and lead isotopes. The dominant particle source to the area are the Trumaos which are the local ando soils derived from the weathering of volcanic deposits. In Galletue, although short term events of enhanced particle inputs occur, elemental and isotopic signatures show that the Trumaos are the only particle source to the area. In San Pablo de Tregua, punctual events of crustal particle inputs are recorded in Pb enrichment factors and isotopic profiles, reflecting a long range crustal involvement. This site also records the inception of the anthropogenic in the area in recent samples of which Pb enrichment factors and lead isotopic signatures shift drastically. [less ▲]

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See detailGeochemical composition of sediments in the Scheldt
Bouezmarni, Mohamed ULg; Wollast, Roland

in Hydrobiologia (2005), 540(1-3), 155-168

Superficial sediments of the Scheldt estuary were collected with a Van Veen grab at 57 stations between Temse and Vlissingen. They were analysed for major elements (Si, Al, Fe, Ca, Mg, Na, K, Cinorg and ... [more ▼]

Superficial sediments of the Scheldt estuary were collected with a Van Veen grab at 57 stations between Temse and Vlissingen. They were analysed for major elements (Si, Al, Fe, Ca, Mg, Na, K, Cinorg and Corg) and trace metals (Cd, Pb, Cu, Zn, Cr, Ni, Co, Mn and Li). Factor analysis indicates that 44% of the variance can be explained by one factor which exhibits a high saturation for trace metals, organic matter, Al and Fe, all variables typical of fine mud. The high scores of this first factor are almost exclusively present in the upper estuary except for one area in front of Terneuzen. The second factor, which explains 23% of the variance, is typical of the carbonates and the third one (19% of the variance) is representative of the clay minerals. These two factors are more evenly distributed over the estuary. As usual, a strong influence of granulometry on the distribution of trace elements in the sediments was observed. Intercomparison of their composition within the Scheldt or with those of other aquatic systems requires thus a normalization procedure. This problem has been studied in detail by analysing various size fractions (63–16, 16–8, 8–4, <4 m) obtained by elutriation of the sample or by using a parameter characteristic of the fine fraction such as the concentration of a typical element (Al, Fe, Li, Corg). The normalization of trace metals allowed us to evaluate an enrichment factor of the trace elements in the estuarine deposits due to mans activities. In addition, it demonstrates the decrease of the anthropogenic impact on the composition of sediments by comparing the composition of sediments collected in 1976 and in 1994. [less ▲]

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See detailGeochemical constraints on the genesis of the Tellnes Ilmenite deposit, southwest Norway
Wilmart, Edith; Demaiffe, Daniel; Duchesne, Jean-Clair ULg

in Economic Geology & the Bulletin of the Society of Economic Geologists (1989), 84

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See detailGeochemical constraints on the petrogenesis of the O'okiep intrusive rocks (Namaqualand, S. Africa) : a lower crustal mafic source
Duchesne, Jean Clair; Vander Auwera, Jacqueline ULg; Clifford, Tom

in Journal of Conference Abstracts (2001), 6

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See detailGeochemical evidence (C, N and Pb isotopes) of recent anthropogenic impact in south-central Chile from two environmentally distinct lake sediment records
Fagel, Nathalie ULg; Bertrand, Sebastien; Mattielli, Nadine et al

in Journal of Quaternary Science (2010), 25(7), 1100-1112

In this paper, we compare the elemental and isotopic (C, N, Pb) geochemistry of lake sediments from two contrasted environments in south-central Chile. The first lake, Laguna Chica de San Pedro (LCSP), is ... [more ▼]

In this paper, we compare the elemental and isotopic (C, N, Pb) geochemistry of lake sediments from two contrasted environments in south-central Chile. The first lake, Laguna Chica de San Pedro (LCSP), is situated in the urbanised area of the Biobio Region (36°S). The second lake, Lago Puyehue (40° S), is located 400 km to the southeast of LCSP and within an Andean national park. Our aim is to identify environmental impacts associated with increasing industrial activities and land degradation during the last 150 a. In LCSP, shifts in C/N atomic ratios, 13C and 15N from 1915-1937 to the late 1980s are attributed to successive land degradation episodes in the lake watershed. Based on a Pb isotopic mixing model, we estimate that up to 20% of lead in LCSP sediments is supplied from urban atmospheric pollution. By contrast, human impact in the watershed of Lago Puyehue is very limited. We observe no change in organic geochemistry during the last 150 a and lead contamination remains lower than 5%, even during the last decades. Although contamination levels are much higher in LCSP than in Lago Puyehue, a peak in anthropogenic Pb is recorded during the same period (1974-1976) at both sites. This maximum contamination level is consistent with increased industrial activity in the vicinity of Concepción. [less ▲]

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See detailGeochemistry and XRD to differentiate oolitic ironstone geological levels from Germany, Belgium and France and application to the archaeological artefacts
Salomon, Hélène ULg; Goemaere, Eric; Mathis, François ULg et al

Conference (2013, February 07)

Particle Induced X-ray Emission (PIXE) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) have largely demonstrated their capability to analyse trace elements for determining the ... [more ▼]

Particle Induced X-ray Emission (PIXE) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) have largely demonstrated their capability to analyse trace elements for determining the origin of archaeological materials. Trace elements can in fact be used as fingerprint of the geological origin and thus contribute to provenance investigations. This point is an important question for prehistoric studies, as it provides information on mobility, exchanges and interaction between groups of population. We present experimental PIXE configurations which allow to investigate prehistoric oolithic haematite, at the ppm level without any preparation or sampling. We compare the data obtained with two devices, namely AGLAE (Accélérateur Grand Louvre d'Analyse Elémentaire) in Paris and the cyclotron in the Centre Européen d'archéométrie in Liège and we determined the uncertainties of measures. The geological samples were compared in order to estimate de geochemical variability in stratigraphy and in width of oolithic haematite from the Ordovician in Caen region (France) and from the Devonian in Hesbaye (Belgium). These data were also compared to oolithic haematite used during Mesolithic and LBK (Early Neolithic) in both the regions. Furthermore we looked for mineralogical fingerprints by X-Ray Diffraction on disoriented powders. The mineralogical composition is ubiquitous and no discrimination between the stratigraphical layers was possible. [less ▲]

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See detailGeochemistry of bitter brines in the Salar de Coipasa - Bolivia
Lebrun, Vincent; Pacosillo, Pedro; Gutierrez, Jorge et al

in Aardkundige Mededelingen (2002), 12

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See detailGeochemistry of continental rivers of the Virunga Volcanic Province, East Africa
Balagizi, C; Darchambeau, François ULg; Kasereka, M et al

Conference (2013)

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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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