References of "Juvigné, Etienne"
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See detailTime-history of the gravel sheet in Ardennian rivers over the last 100,000 years
Houbrechts, Geoffrey ULg; Denis, Anne-Cécile ULg; Juvigné, Etienne ULg et al

Poster (2013, August 27)

It is generally held that, in north-western Europe, the main part of the gravel sheets under river beds were deposited during the Weichselian period in a periglacial environment. However, other parameters ... [more ▼]

It is generally held that, in north-western Europe, the main part of the gravel sheets under river beds were deposited during the Weichselian period in a periglacial environment. However, other parameters such as propagation of knickpoints in fluvial networks may also influence incision or aggradation. However, only few studies have dated the periods of formation of the gravel sheets and have described their properties. The first aim of this research was to determine the thickness of the gravel sheets still remaining under the river beds and to estimate the potential incision of these rivers before reaching the bedrock. Then we tried to answer a number of other questions: When did these thick gravel deposits fill the valley bottom? When were the lowest terraces abandoned? When did the rivers incise the bedrock? What is the morphology of the bedrock under the gravel layer? Numerous boreholes were made by percussion drilling in different floodplains of the Ardenne Massif and core samples were taken, down to the bedrock. Afterwards, different volcanic tephra from the Late Pleistocene were used as stratigraphic markers to date the relative periods of terrace formation and to reconstruct the past evolution of the gravel sheets. Pollen and metallurgic slag were also used to date the periods of bed level evolution. In the Ardennian massif, the thickness of the gravel sheet beneath the river beds is very variable (from 10 m in the downstream part of the Ourthe River to less than 1 m in the upper catchments). In some valleys, weathered bedrock has been observed under the gravel sheet to a thickness of several meters. Different phases of accumulation and incision over the last 100,000 years have been dated. Some evolutions can be clearly linked to climate changes but some modifications of bed levels also occurred during the Weichselian period and could be a response to the propagation of knickpoints in the fluvial networks. [less ▲]

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See detailLa pente longitudinale de la terrasse principale de la Meuse revisitée de Seilles à Huy
Juvigné, Etienne ULg; Di Modika, Kevin; Houbrechts, Geoffrey ULg et al

in Bulletin de la Société Géographique de Liège (2013), 61

Des relevés altimétriques géoréférencés ont été appliqués à des contacts cailloutis/substratum de lambeaux de la terrasse principale T4 de la Meuse entre Namur et Liège, à Seilles/Andenne et à Wanze/Huy ... [more ▼]

Des relevés altimétriques géoréférencés ont été appliqués à des contacts cailloutis/substratum de lambeaux de la terrasse principale T4 de la Meuse entre Namur et Liège, à Seilles/Andenne et à Wanze/Huy. Il en résulte que la pente longitudinale du tronçon étudié est identique à celle de la plaine alluviale actuelle, tandis que des travaux antérieurs basés sur l’interprétation de cartes topographiques y voient une contre-pente et impliquent donc inutilement une déformation tectonique pendant le Quaternaire dans le secteur étudié. [less ▲]

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See detailLa pente longitudinale de la terrasse principale de la Meuse revisitée de Seilles à Huy
Juvigné, Etienne ULg; Di Modika, Kevin; Houbrechts, Geoffrey ULg et al

in Bulletin de la Société Géographique de Liège (2013), 61

Des relevés altimétriques géoréférencés ont été appliqués à des contacts cailloutis/substratum de lambeaux de la terrasse principale T4 de la Meuse entre Namur et Liège, à Seilles/Andenne et à Wanze/Huy ... [more ▼]

Des relevés altimétriques géoréférencés ont été appliqués à des contacts cailloutis/substratum de lambeaux de la terrasse principale T4 de la Meuse entre Namur et Liège, à Seilles/Andenne et à Wanze/Huy. Il en résulte que la pente longitudinale du tronçon étudié est identique à celle de la plaine alluviale actuelle, tandis que des travaux antérieurs basés sur l’interprétation de cartes topographiques y voient une contre-pente et impliquent donc inutilement une déformation tectonique pendant le Quaternaire dans le secteur étudié. [less ▲]

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See detailLa pente longitudinale de la terrasse principale de la Meuse revisitée de Seilles à Huy
Juvigné, Etienne ULg; Di Modika, Kevin; Houbrechts, Geoffrey ULg et al

in Bulletin de la Société Géographique de Liège (2013), 61

Des relevés altimétriques géoréférencés ont été appliqués à des contacts cailloutis/substratum de lambeaux de la terrasse principale T4 de la Meuse entre Namur et Liège, à Seilles/Andenne et à Wanze/Huy ... [more ▼]

Des relevés altimétriques géoréférencés ont été appliqués à des contacts cailloutis/substratum de lambeaux de la terrasse principale T4 de la Meuse entre Namur et Liège, à Seilles/Andenne et à Wanze/Huy. Il en résulte que la pente longitudinale du tronçon étudié est identique à celle de la plaine alluviale actuelle, tandis que des travaux antérieurs basés sur l’interprétation de cartes topographiques y voient une contre-pente et impliquent donc inutilement une déformation tectonique pendant le Quaternaire dans le secteur étudié. [less ▲]

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See detailLa pente longitudinale de la terrasse principale de la Meuse revisitée de Seilles à Huy
Juvigné, Etienne ULg; Di Modika, Kevin; Houbrechts, Geoffrey ULg et al

in Bulletin de la Société Géographique de Liège (2013), 61

Des relevés altimétriques géoréférencés ont été appliqués à des contacts cailloutis/substratum de lambeaux de la terrasse principale T4 de la Meuse entre Namur et Liège, à Seilles/Andenne et à Wanze/Huy ... [more ▼]

Des relevés altimétriques géoréférencés ont été appliqués à des contacts cailloutis/substratum de lambeaux de la terrasse principale T4 de la Meuse entre Namur et Liège, à Seilles/Andenne et à Wanze/Huy. Il en résulte que la pente longitudinale du tronçon étudié est identique à celle de la plaine alluviale actuelle, tandis que des travaux antérieurs basés sur l’interprétation de cartes topographiques y voient une contre-pente et impliquent donc inutilement une déformation tectonique pendant le Quaternaire dans le secteur étudié. [less ▲]

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See detailLe Ru de Pôleur ancien et sa capture par le Hoëgne
Juvigné, Etienne ULg; Demoulin, Alain ULg; Houbrechts, Geoffrey ULg

in Hautes Fagnes (2013), (1), 18-21

A un moment indéterminé de la période continentale tertiaire qui a suivi le retrait de la mer oligocène des Hautes Fagnes, le Ru de Pôleur (actuellement Hoëgne supérieure) poursuivait son cours vers l'WSW ... [more ▼]

A un moment indéterminé de la période continentale tertiaire qui a suivi le retrait de la mer oligocène des Hautes Fagnes, le Ru de Pôleur (actuellement Hoëgne supérieure) poursuivait son cours vers l'WSW par l’ensellement de Hockai. Au-delà, il empruntait soit la vallée du Ru de Hockai, soit celle du Roannai. Dans les deux cas, il a probablement rencontré la Warche à la bordure occidentale du replat de Cronchamps. Ensuite, il a été capturé en conséquence de l’érosion régressive de la Hoëgne moyenne qui dévalait le flanc NO de la crête de la Vecquée. Ce processus a eu lieu pendant la seconde moitié du Tertiaire, et il a été facilité par l’altération des roches due à la présence de failles transversales perpendiculaires à la crête de la Vecquée à l’endroit du coude que décrit maintenant la vallée. [less ▲]

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See detailReconstitution de la dynamique d'une rivière ardennaise (La Lienne) depuis le Tardiglaciaire grâce à l'analyse géomorphologique et chronostratigraphique d'une tourbière de fond de vallée
Denis, Anne-Cécile ULg; Wastiaux, Cécile ULg; Petit, François ULg et al

in Géomorphologie : Relief, Processus, Environnement (2013), 2

The geomorphological dynamics (incision, lateral mobility, sedimentation rate) of a river typical of the Ardenne region (the Lienne River) were studied at the level of a valley floor peat deposit. This ... [more ▼]

The geomorphological dynamics (incision, lateral mobility, sedimentation rate) of a river typical of the Ardenne region (the Lienne River) were studied at the level of a valley floor peat deposit. This type of site is of major interest as the morphology of ancient fluvial deposits is preserved underneath peat deposits and pollen conserved in the peat allows different phases of the evolution of the river to be dated. The presence of pollen from the Younger Dryas above a pebble sheet perched 1.4 m above the present-day bed, as well as peat deposits from the Preboreal at the level of the present-day bed indicate that a phase of incision occurred during the Younger Dryas-Preboreal transition. Reworked Laacher See tephra was found in the upper part of the perched pebble sheet, which confirms that it had been laid down during the Younger Dryas, in a periglacial context. The Lienne River had probably multiple channels during the Preboreal. After the abandonment of one of the channels, it moved laterally, allowing the peat to spread until it occupied more than two-thirds of valley from the Atlantic phase. The use of slag from steel working as a stratigraphic marker shows low lateral mobility in the Lienne River as well as a low rate of aggradation of the alluvial plain over the last centuries. [less ▲]

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See detailL'origine des mégalithes du Fond de Quarreux (Ardenne, Belgique)
Collard, Sébastien; Juvigné, Etienne ULg; Marion, Jean-Marc ULg et al

in Bulletin de la Société Géographique de Liège (2012), 58

Origin of megaliths of the Fond de Quarreux (Ardenne, Belgium). Distribution of megaliths was studied in the Ambleve valley throughout its gorge developed within the quartzites of the Cambrian-aged La ... [more ▼]

Origin of megaliths of the Fond de Quarreux (Ardenne, Belgium). Distribution of megaliths was studied in the Ambleve valley throughout its gorge developed within the quartzites of the Cambrian-aged La Venne Formation (Fond de Quarreux) in the south-eastern part of high Belgium. The high concentration of megaliths at this place can be essentially explained by mass movements which have occurred on the adjacent slopes in periglacial periods of cold Ocean Isotopic Stages in Quaternary times, and especially the coldest ones i.e. even O.I.S.#22 through #2. Stratigraphical studies of deposits in the Chefna and Ambleve valleys allowed us to place final periglacial deposits during the Younger Dryas. The critical shear stress and the critical unit stream power are used in order to evaluate the Ambleve River competence. It results that, under the present climatic conditions, this river cannot move boulders of more than 50 cm in diameter. Hence, it is concluded that ice rafting has been the main process responsible for carrying away the megaliths which have got the Ambleve river bed throughout the Quaternary Period. [less ▲]

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See detailL'envasement du lac de Butgenbach (Ardenne, Belgique)
Hallot, Eric ULg; Benoit, Morgan; Stasse, Guillaume et al

in Bulletin de la Société Géographique de Liège (2012), 59

In 2004, the Butgenbach lake reservoir (Warche river) has been emptied for the first time since 1932. The sediments deposited have been studied with a double objective : on the one hand to determine the ... [more ▼]

In 2004, the Butgenbach lake reservoir (Warche river) has been emptied for the first time since 1932. The sediments deposited have been studied with a double objective : on the one hand to determine the volume of sediment deposits, and on the other hand to estimate mean soil erosion rate in the catchment. Some five hundreds manual augerings were made using a thin auger (15 mm) throughout the wet and soft sediments (mud) in order to identify the lake deposits that have overlain the previous soft material (flood silts in the flood plain of the river Warche, silty soils on the slopes). Since the expected boundary between both types of materials could not be identified by the naked eye, a qualitative analysis of diatoms, magnetic susceptibility, grain-size distribution and calcination has been made for fifteen thicker cores (3.6 mm across) taken at representative sites. Mean annual area-specific sediment yield amounts to 28 – 33 t.km-².y-1 [less ▲]

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See detailVariabilité des enregistrements polliniques en montagne et reconstitutions paléoécologiques.
David, F; Damblon, F; Farjanel, G et al

in Belgeo (2006), 3

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See detailMetallurgic slag as a tracer in floodplain evolution studies
Houbrechts, Geoffrey ULg; Petit, François ULg; Juvigné, Etienne ULg et al

Conference (2005)

The aim of this study was to estimate sedimentation rates in floodplains and to investigate lateral channel migrations over the last centuries. Considering the difficulties in determining these parameters ... [more ▼]

The aim of this study was to estimate sedimentation rates in floodplains and to investigate lateral channel migrations over the last centuries. Considering the difficulties in determining these parameters using traditional dating methods, we have used different kinds of slag rejected from former metal works. In the Ardenne region (southern part of Belgium), at the end of 14th century, iron factories moved near to rivers in order to take advantage of the hydraulic energy. At the same time, large quantities of slag produced in primitive blast furnaces were piled onto the floodplains, often very close to rivers. Consequently, microslag could be carried away either during floods or by lateral erosion to be deposited on the floodplains downstream. In order to use slag as a stratigraphical tracer, we located slag waste sites along rivers and we dated the periods of furnace activity from historical studies. Afterwards, we measured slag concentrations in the alluvium and we studied their evolutions in different borings. These results allowed us to reconstruct the appearance of the floodplain at the inception of the metal works and to estimate lateral channel mobility over several centuries. Moreover, different kind of tephra and 14C dating have been used in order to date the deposits that have been established before the settlement of metallurgy. [less ▲]

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See detailPhosphate mineral formation in Lake Baïkal sediments and implications for paleoclimate
Fagel, Nathalie ULg; Alleman, L. Y.; André, Luc et al

Poster (2003)

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See detailPhosphate mineral occurrences in Lake Baïkal sediments : Paleo-environment or diagenesis record ?
Fagel, Nathalie ULg; Alleman, L. Y.; André, Luc et al

Poster (2003)

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See detailA method for estimating the migration time of plant species within the time range of 14C-Dating.
Juvigné, Etienne ULg; Bastin, B; Delibrias, G et al

in Quaternary International (1998), 47/48

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See detailA comprehensive pollen- and tephra- based chronostratigraphic model for the Late Glacial and Holocene Period in the French Massif Central.
Juvigné, Etienne ULg; Bastin, B; Delibrias, G et al

in Quaternary International (1996), 34-36

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See detailThe Stavelot Massif from Cambrian to recent. A survey of the present state of knowledge
Bless, M. J. M.; Bouckaert, J.; Camelbeek, L. et al

in Annales de la Société Géologique de Belgique (1990)

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See detailDes traces de glace de ségrégation dans la grotte de Remouchamps (Belgique) : conséquences en ce qui concerne la sédimentation et la paléoclimatologie
Pissart, Albert ULg; Van Vliet-Lanoë, Brigitte; Ek, Camille ULg et al

in Annales de la Société Géologique de Belgique (1988), 111

In countries with a modern temperate climate, the extent of former permafrost is generally estimated from the observation of ice wedge casts, remnants of pingos and palsas, and periglacial involutions ... [more ▼]

In countries with a modern temperate climate, the extent of former permafrost is generally estimated from the observation of ice wedge casts, remnants of pingos and palsas, and periglacial involutions. These features give no indication at all about the depth of permafrost and are ineffective in identifying the limits of former permafrost. A new tool for this research may be found in caves. We already know that speleothems did not grow -- or grew little — during the colder periods of the last glaciation, probably because of the impervious nature of the frozen ground. The discovery, in the Remouchamps Cave, of the marks of segregation ice in loose fills proves that the temperature did fall below 0°C. Only one cycle of freeze/thaw would have been sufficient to create these marks wich have been preserved because there was indeed little biological activity in this environment. The temperature in such caves is generally very close to the mean annual temperature outside the caves. This evidence will thus be useful for tracing the southern limit of the permafrost in Europe. When the permafrost thawed, the melting of the ice caused mass movements in the cave sediments. The ice had blocked some passages and water levels rose to abnormally high levels, depositing sediments at these levels. [less ▲]

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