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See detailWEATHERING ON THE DEVONIAN SLATES AND CHARACTERIZATION OF A BENTONITE LAYER IN THE WESTERWALD (GERMANY)
Fontaine, François ULg; 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 detailA climatic change at the Danian/Selandian boundary: increasing weathering fluxes
Devleeschouwer, Xavier; Wouters, Sébastien ULg; Riquier, Laurent et al

Conference (2016)

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See detailGeoheritage in Ardennes (France and Belgium): geology, cultural heritage and landscapes
Fronteau, Gilles; Yans, Johan; Boulvain, Frédéric ULg et al

in Mémoire hors série de la Société géologique de France (2016), 16

The geology of the Western part of the Ardenne Massif is renowned by various stratotypical outcrops. But the Ardennes, highlighted with the geoheritage point of view, can show other specific topics. Some ... [more ▼]

The geology of the Western part of the Ardenne Massif is renowned by various stratotypical outcrops. But the Ardennes, highlighted with the geoheritage point of view, can show other specific topics. Some of these topics are based on geomaterials: the slates from the Cambrian formations, the ancient millstones quarries in lower Devonian sandstones, the red "marbles" and blue or black ornamental limestones from middle and upper Devonian, the fluorine deposits... Others are focused on geomorphological specific sites, linked to local legends. These sites, sometimes already included in the touristic promotion of the Ardennes, can be an excellent entry point to encourage the emergence of a transnational Geopark project in this area. [less ▲]

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See detailIntegrated bio-chemostratigraphical correlations and climatic evolution across the Danian-Selandian boundary at low latitudes
Storme, Jean-Yves ULg; Steurbaut, Etienne; Devleeschouwer, Xavier et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2014), 414

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See detailCarbon-isotope analysis of fossil wood and dispersed organic matter from the terrestrial Wealden facies of Hautrage (Mons Basin, Belgium).
Yans, Johan; Gerards, Thomas ULg; Gerrienne, Philippe ULg et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2010), 291

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See detailCenomanian sands and clays north of the Vesdre valley: the oldest known Cretaceous deposits in eastern Belgium
Demoulin, Alain ULg; Quesnel, Florence; Dupuis, Christian et al

in Geologica Belgica (2010), 11(3), 241-256

A number of motored auger holes have been drilled in 2002 and 2006 in four sand-clay deposits preserved in dissolution pockets within the Dinantian limestones of the watershed north of the Vesdre valley ... [more ▼]

A number of motored auger holes have been drilled in 2002 and 2006 in four sand-clay deposits preserved in dissolution pockets within the Dinantian limestones of the watershed north of the Vesdre valley. These deposits of unknown age are currently classified as (Tertiary) SBL in the new geological map of Wallonia. We present detailed lithostratigraphic logs of the deposits and describe the results of sedimentological and mineralogical analyses. In particular, K-Ar dating of neoformed Mn oxides found at the base of one augerhole at Rechain yielded ages ranging from Cenomanian to Santonian, allowing us to place the Rechain and Andrimont deposits within the early Late Cretaceous. This is fully consistent with their topographic location very close beneath the trace of the pre-Cretaceous erosion surface and makes them the westernmost remains of the Hergenrath Member of the Late Cretaceous Aachen Formation. To the west, the Magnée deposit is more “typical SBL”, probably corresponding to the Late Neogene filling of a dissolution pocket by reworked weathering products of the local Cretaceous cover. [less ▲]

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See detailAn overview of the geology of Belgium.
Pirson, Stéphane ULg; Spagna, Paul; Baele, Jean-Marc et al

in Memoirs of the Geological Survey of Belgium (2008), 55

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See detailWood remains and sporomorphs from the Wealden facies of Hautrage (Mons Basin, Belgium): palaeoclimatic and palaeoenvironnemental implications.
Gerards, Thomas ULg; Yans, Johan; Spagna, Paul et al

in Memoirs of the Geological Survey of Belgium (2008), 55

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See detailQuelques implications paléoclimatiques de l'observation de bois fossiles du Wealdien du bassin de Mons (Belgique) - Résultats préliminaires.
Gerards, Thomas ULg; Yans, Johan; Gerrienne, Philippe ULg

in Carnets de Géologie = Notebooks on Geology (2007), 2007(01), 29-34

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