References of "Fontaine, François"
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See detailHigh-temperature XRD investigations of phase transformation in mineralogy: examples for clay used in ceramics and phosphate minerals
Fontaine, François ULiege; Hatert, Frédéric ULiege; Fagel, Nathalie ULiege

Poster (2018, September)

High-temperature X-ray diffraction is a technique used to determine the mineralogy of a sample at various, non-ambient, temperatures. It allows the measurement and visualisation of dehydration and ... [more ▼]

High-temperature X-ray diffraction is a technique used to determine the mineralogy of a sample at various, non-ambient, temperatures. It allows the measurement and visualisation of dehydration and oxidation processes, phase transformations (Wahl et al., 1961; Montanari, 2004; Zamporti et al., 2012), reaction processes and crystallite growth (Natter et al., 2001). The approach was tested on two distinct materials, i.e. raw clays used for ceramic production and phosphate minerals. Four clay samples from Westerwald (Germany) were chosen: a Fe rich illite clay, a red, a yellow and a white clay. In addition, two natural phosphate samples were selected: alluaudite [Na2MnFe2+Fe3+(PO4)3] from Townsite, Pringle, South Dakota, USA (sample TOW-01; Hatert, 2002), and triphylite [LiFe2+(PO4)] from Palermo pegmatite, New Hamshire, USA. Mineral transformation and vitrification processes were followed from 30 to 1250°C. [less ▲]

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See detailRaman microspectroscopy, bitumen reflectance and illite crystallinity scale: comparison of different geothermometry methods on fossiliferous Proterozoic sedimentary basins (DR Congo, Mauritania and Australia)
Kabamba Baludikay, Blaise ULiege; François, Camille ULiege; Sforna, Marie-Catherine ULiege et al

in International Journal of Coal Geology (2018)

Sedimentary rocks containing microfossils are crucial archives to reconstitute early life evolution on Earth. However, the preservation of microfossils within rocks depends on several physico-chemical ... [more ▼]

Sedimentary rocks containing microfossils are crucial archives to reconstitute early life evolution on Earth. However, the preservation of microfossils within rocks depends on several physico-chemical factors. Among these factors, the thermal evolution of the host rocks can be decisive. Here, we investigated carbonaceous shale samples containing exquisitely preserved organic-walled microfossils assemblages from three Proterozoic shallow marine sedimentary sequences: the Mbuji-Mayi Supergroup (Democratic Republic of Congo, Congo Basin), the Atar/El Mreïti Group (Mauritania, Taoudeni Basin) and the Kanpa Formation (Australia, Officer Basin). Thermal maturity of these rock samples is evaluated with Raman geothermometry, Raman reflectance, solid bitumen reflectance, illite crystallinity and Thermal Alteration Index. The comparison of results coming from these different techniques validates the use of Raman reflectance on Proterozoic carbonaceous material and especially for poorly-ordered carbonaceous material. We show that extracted kerogen (microfossils and amorphous organic material) is more accurate to estimate the thermal maturity of low-grade temperature Proterozoic sequences than kerogen in thin section. All techniques provide consistent range of temperatures except for Raman geothermometry, giving slightly higher estimates. Raman reflectance appears to be a fast, robust and non-destructive tool to evaluate the thermal maturity of poorly-organized carbonaceous material from Proterozoic rocks. [less ▲]

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See detailUse of different geothermometry methods on fossiliferous Proterozoic sediments to constrain thermal maturity of microfossils and sedimentary basins (DRCongo, Mauritania & Australia)
Kabamba Baludikay, Blaise ULiege; François, Camille ULiege; Sforna, Marie-Catherine ULiege et al

Poster (2018, March)

Evaluate the thermal maturity of old sedimentary basins containing microfossils is crucial to reconstruct early life evolution on Earth. Here, we investigate carbonaceous shale samples containing ... [more ▼]

Evaluate the thermal maturity of old sedimentary basins containing microfossils is crucial to reconstruct early life evolution on Earth. Here, we investigate carbonaceous shale samples containing exquisitely preserved organic-walled microfossil assemblages from three Proterozoic shallow marine sedimentary sequences: the Mbuji-Mayi Supergroup (Democratic Republic of Congo, Congo Basin), the Atar/El Mreïti Group (Mauritania, Taoudeni Basin) and the Kanpa Formation (Australia, Officer Basin). By comparison with Raman geothermometry, solid bitumen reflectance, illite crystallinity and Thermal Alteration Index, we evaluate and validate the use of Raman reflectance on Proterozoic carbonaceous material and especially for poorly-ordered carbonaceous material. We show that extracted kerogen (microfossils and amorphous organic material) is more accurate to estimate the thermal maturity of low-grade temperature Proterozoic sequences than kerogen in thin section. All the techniques provide consistent range of temperatures except for Raman geothermometry, giving slightly higher estimates. Raman reflectance appears to be a fast and robust tool to evaluate the thermal maturity of poorly-organized carbonaceous material from Proterozoic rocks and by extension could be used to assess the thermal evolution of a sedimentary successions. This work was supported by the ERC StG ELITE FP7/308074; BELSPO IAP PLANET TOPERS, and the Marie-Curie Cofund program. [less ▲]

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See detailWEATHERING ON THE DEVONIAN SLATES AND CHARACTERIZATION OF A BENTONITE LAYER IN THE WESTERWALD (GERMANY)
Fontaine, François ULiege; Hamaekers, Helen; Hoffmann, Andreas et al

Conference (2017, July)

The Westerwald region is one of the largest and oldest clay mining areas of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of ... [more ▼]

The Westerwald region is one of the largest and oldest clay mining areas of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of Devonian rocks. During the Miocene, intense volcanic activities led to a large basalt cover, protecting the clays from the erosion. The two main goals of this study are first to improve the knowledge on the weathering processes of the Devonian slates that led to the current setting of those clay deposits by studying the mineralogical and chemical composition of the clays with depth. The second goal is to characterize a bentonite layer underneath the Miocene basalt cover using quantitative X-ray diffraction, chemical analysis, BET, cation exchange capacity and scanning electron microscope. A 20 meter deep quarry mining the Devonian bedrock in southern Westerwald has been sampled on its entire depth. The XRD results show no significant variations of the mineralogy with depth, except for the phyllosilicates. The minerals of the < 2 μm fraction are illite, kaolinite, smectite and mixed-layers minerals (vermiculite-chlorite and illite-chlorite). The proportions of the minerals in the mixed-layers chlorite-vermiculite vary with depth. At the bottom of the quarry, the proportion of vermiculite is very low while in the top, the proportion of vermiculite is higher. This is explained by the degree of the weathering, logically more intense at the top of the quarry. Trace elements compositions are currently being investigated. A 3 meter thick greenish to brownish bentonite layer has been found in the eastern part of the Westerwald region. The XRD performed on different samples of this bentonite shows a relatively heterogeneous composition: montmorillonite (60-80%), kaolinite (5-12%), illite (0-7%), goethite (2-15%), talc (0-10%), K-feldspars (0-7%), plagioclase (0-4%) and traces of amphibole and pyroxene. This bentonite is probably the result of the weathering of volcanic ashes. Since there are not many outcrops of this bentonite layer, its spatial distribution is studied by drilling. [less ▲]

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See detailHigh-temperature and quantitative XRD study of typical Westerwald clays (Germany)
Fontaine, François ULiege; Fagel, Nathalie ULiege

Poster (2016, July 05)

The Westerwald is one of the largest and oldest clay mining area of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of Devonian ... [more ▼]

The Westerwald is one of the largest and oldest clay mining area of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of Devonian rocks. During the Miocene, intense volcanic activities led to a large basalt cover, protecting the clays from the erosion. The fine fraction is mainly composed of kaolinite and illite, with the possible presence of interstratified I S. Other minerals such as quartz, feldspars, hematite, goethite or anatase are present in variable concentrations. Four typical Westerwald clays were chosen for this study: kaolinite-rich clay, kaolinite-illite clay, a red and a yellow firing clays. The first goal is to perform quantitative XRD using two different methods and to compare them: reference intensity ratio (RIR) and Rietveld (using Topas and BGMN). The second goal is the study of those samples using high-temperature XRD (HTXRD). The samples were heated up to 1250°C and a XRD pattern was obtained in situ every 100°C. The results show the temperatures of vitrification and formation of mullite and cristobalite varying from one sample to another, which is mainly linked to their flux concentration. [less ▲]

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See detailReconstitution des paléoenvironnements et des activités humaines à partir de l’étude de sédiments prélevés dans le Cap Corse (Corse, France)
Fagel, Nathalie ULiege; Fontaine, François ULiege; Pleuger, Elisa ULiege et al

in Ghilardi, Mathieu (Ed.) La géoarchéologie des îles de Méditerranée (2016)

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See detailCrystal structure of bassetite and saléeite: new insight into autunite-group minerals
Dal Bo, Fabrice ULiege; Hatert, Frédéric ULiege; Mees, Florias et al

in European Journal of Mineralogy (2016)

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See detailIdentification of the main parameters controlling the plasticity of ceramic pastes: The case study of the Marrakech region (Morocco)
El Boudour El Idrissi, Hicham ULiege; Daoudi, Lahcen; Fontaine, François ULiege et al

Poster (2015, July)

Numerous traditional ceramic workshops occur within a range of 10 to 80 km around the city of Marrakech. Our study aims to identify the main parameters controlling the plasticity of pastes used by the ... [more ▼]

Numerous traditional ceramic workshops occur within a range of 10 to 80 km around the city of Marrakech. Our study aims to identify the main parameters controlling the plasticity of pastes used by the artisans. To reach this goal, we characterize by X-ray diffraction, granulometry and plasticity index (PI) the local raw clayey material. <br />The investigation of 26 whole pastes shows the dominance of quartz (20 to 50%) and clay minerals (25 to 60%) with K-feldspar (2 to 17%), plagioclase (2 to 25%), calcite (0 to 18%), dolomite (0 to 15%), goethite (0 to7%) and trace of hematite and anhydrite (< 3%). Amphibole occurs in trace (< 5%) but only in some samples. The clay minerals are diversified, including illite (10 to 40%), kaolinite (2 to 15%), mixed-layer (ML) (0 to 10%), smectite, vermiculite and chlorite (0 to 5%), and pyrophyllite-talc association (0 to 8%). Sepiolite (12%) is only present in one paste. The grain size is made by variable proportions of sand (5 to 65%), silt (12 to 53%) and clayey fraction (18 to 66%). <br />The Plasticity index (PI) indicates the presence of two principals groups of pastes. <br />(1) The first group is characterized by PI values ranging between 15 to 18. Their moderate plasticity behavior is related either to the low rate of clayey fraction and/or to the absence of plastic clays like smectites and mixed layer with smectitic sheets. <br />(2) The PI of second group ranges between 20 to 32. The high plasticity values are influenced by the presence of specific clayey minerals like talc-pyrophyllite or sepiolite, or by the high content of smectite plus smectitic mixed-layers within the clayey (< 2 micron) fraction. Only one sample without any of these plastic minerals but with a high content of clayey fraction is characterized by a high PI value (24). <br />We concluded that the workability of ceramic paste in Marrakech region is controlled by a combination of factors, dominated by the grain size distribution and the content in plastic clay minerals within the fine fraction. [less ▲]

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See detailETUDE DES SÉDIMENTS COTIERS DU CAP CORSE: RECONSTRUCTION PALÉOENVIRONNEMENTALE ET SUIVI DE LA CONTAMINATION EN ÉLÉMENTS TRACES MÉTALLIQUES AU COURS DE LA PÉRIODE HISTORIQUE
Fontaine, François ULiege; Goiran, Jean-Philippe; PRUDENCIO, Isabel et al

Conference (2014, April)

Les sédiments sont d’excellentes archives de la contamination de notre environnement. Depuis l’Antiquité, les activités humaines génèrent des aérosols anthropiques enrichis en métaux lourds (e.g. Pb, Zn ... [more ▼]

Les sédiments sont d’excellentes archives de la contamination de notre environnement. Depuis l’Antiquité, les activités humaines génèrent des aérosols anthropiques enrichis en métaux lourds (e.g. Pb, Zn, Cu, Cd, Hg) ou associés (As, Sb). Ces polluants métalliques se mélangent aux aérosols naturels (altération des roches) et leurs retombées sont incorporées dans les sols et les sédiments où ils sont préservés (Boyd, 2004). Sur des sédiments datés, une approche géochimique permet de quantifier l’apport anthropique en éléments métalliques par rapport aux sources naturelles et de reconstituer l’historique de la pollution. Les côtes méditerranéennes sont caractérisées par d’intenses échanges commerciaux, et ce depuis l’Antiquité. Nous proposons une reconstruction paléoenvironnementale ainsi qu’un suivi de la contamination anthropique au cours de la période historique pour différents sites du Cap Corse (France ; Figure 1). Cette région de Méditerranée se caractérise par une riche activité économique au cours de la période historique. Depuis le VIème siècle, la Corse a été colonisée successivement par les Grecs, les Carthaginois, les Etrusques puis par les Romains. En milieu continental, des témoins archéologiques (sépulture, oppidum, chapelle) attestent d’une occupation de cette zone sur une période assez longue. Cependant de nombreuses interrogations subsistent quant à l’importance des établissements, leurs périodes d’occupation, leurs activités économiques et leurs rapports commerciaux avec les autres cités du Cap Corse et des côtes méditerranéennes (de La Brière, 2010). Des carottes de 1 m à 1,5 m ont été prélevées à la tarière dans différents sites du Cap Corse. Les concentrations en éléments majeurs et en éléments traces métalliques ont été mesurées par spectrométrie de masse (ICP-MS), activation neutronique (INAA) et par XRF core scanner. Les datations 14C réalisées sur des macrorestes de matières végétales et charbons montrent que ces carottes couvrent toute la période historique, à l’exception de celle prélevée à Méria qui ne couvre qu’environ 300 ans. Cette carotte a également la particularité de contenir d’importantes concentrations en métaux lourds tels que le Sb (2000 ppm) et l’As (300 ppm). Cette contamination est d’origine locale et liée à la présence d’une ancienne mine d’antimoine à 2 km en amont de Méria. Afin d’obtenir un enregistrement sur les 2000 dernières années, un carottage plus long sera réalisé lors d’une nouvelle campagne de terrain. D’autres carottages seront également réalisés entre la mine et la côte actuelle afin d’observer la variation spatiale dans le but de quantifier l’impact environnemental des activités humaines locales et régionales. [less ▲]

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See detailSTUDY OF ENVIRONMENTAL CONTAMINATION OVER THE HISTORICAL PERIOD: TRACE ELEMENT AND LEAD ISOTOPIC SIGNATURE IN COASTAL SEDIMENTS FROM CAP CORSICA (FRANCE)
Fontaine, François ULiege; lefebvre, lucie; Vranken, François et al

Poster (2014, February)

The Mediterranean coasts have been characterised by intense maritime commercial exchanges since Antiquity. Archeological researches reveal that Cape Corsica (France) may have been an ancient Roman harbor ... [more ▼]

The Mediterranean coasts have been characterised by intense maritime commercial exchanges since Antiquity. Archeological researches reveal that Cape Corsica (France) may have been an ancient Roman harbor. The purpose of this study is first to highlight an anthropogenic contamination due to Roman activities using trace element concentration. Second we aim to identify the contamination sources through Pb isotope composition. Radiocarbon ages performed on macroremains in coastal sediments from Cala Francese (cores CF10-II and CF10-III) allow the localisation of the Roman Period in the sedimentary columns. In core CF 10-II, two major shifts of trace element concentration (such as Pb, Cu, Zn, As and Sb) have been measured at 60-80 and 140-160 cm, corresponding respectively to the Industrial Revolution and to the Roman Period. The same tendency of the Pb concentration is observed in core CF10-III. In this core, the Roman Period is localised between 80 and 140 cm. A major shift in Pb isotopic composition is observed in both core at 140 cm in CF10-II and 60 cm in CD10-III, with a decrease of 206Pb/207Pb ratios and 208Pb/206Pb ratios. All the Pb isotopic ratios match with Pb Roman time signatures from Greece and Spain. Such significant changes in trace metal content and in Pb isotopic signature of sediments are consistent with Human perturbations of the environment during the Roman and Industrial periods. The Pb isotopic signatures measured in Cala Francese are in the same range as those located in other sites of Cape Corsica, indicating a regional contamination. [less ▲]

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