References of "Ek, Camille"
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See detailCarbon dioxide in cave air and soil air in some karstic areas of Belgium
Ek, Camille ULg

in Geologica Belgica (2014)

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See detailKarst et CO2. Le transfert de CO2 dans le synclinal carbonifère de Comblain-au-Pont
Ek, Camille ULg; Godissart, Jean

in Ecokarst (2013), 92

CO2, solved in water, is the main factor of karstification. In the caves, CO2 concentration in air raises commonly up to 10 000 ppm and, during summertime, 20 000 and more.

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See detailAir CO2 in Comblain-au-Pont Cave (Belgium). Relationships with soil CO2 and open air meteorology
Godissart, Jean; Ek, Camille ULg

in International Congress of Speleology Proceedings (2013)

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See detailLa dynamique du karst dans le synclinal de Sprimont de 1898 à 2012
Peeters, Alexandre ULg; Ek, Camille ULg; Labarbe, Philippe et al

Conference given outside the academic context (2012)

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See detailDynamique du Karst dans le synclinal de Sprimont de 1898 à 2012
Peeters, Alexandre ULg; Ek, Camille ULg; Labarbe, Philippe et al

Conference (2012, December 08)

1. Une prospection dans le synclinal de Sprimont en 1898 C’est dans un synclinal calcaire de 12 km de long et 1,2 km de large que se situe Sprimont. Le synclinal, qui s’allonge d’est en ouest, est coupé ... [more ▼]

1. Une prospection dans le synclinal de Sprimont en 1898 C’est dans un synclinal calcaire de 12 km de long et 1,2 km de large que se situe Sprimont. Le synclinal, qui s’allonge d’est en ouest, est coupé en deux par la vallée de l’Ourthe. Le présent travail concerne la partie orientale de ce pli. Vers 1898, E. Van den Broeck, E. Martel et E. Rahir parcouraient ce synclinal et cartographiaient ses phénomènes karstiques (Van den Broeck, Martel & Rahir, 1910, vol. ll). 2. Révisions de la cartographie de 1971 à 2000 Raymond Michel entreprit en 1970-71 une révision de la cartographie et constata que beaucoup de pertes s’étaient déplacées, presque toutes vers l’amont, et sur une distance moyenne de 270 m ! Des levés ultérieurs par divers géographes confirmèrent l’extrème mobilité des pertes du vallon et furent consignées dans des cartographies de la CWEPSS et de la DGATLP. À ces mises à jour participèrent notamment D. Closson, A. Jaspar, V. Mousny, M. Salmon, J.-C. Schyns et A. Peeters. 3. Un nouveau levé en 2012 Une nouvelle révision fut entreprise en 2012 par deux équipes qui passèrent chacune trois journées pleines sur le terrain. La prospection s’appuya sur des photos aériennes et les phénomènes furent « géolocalisés » à l’aide d’un petit GPS de terrain (précision env. 10 m). Les pertes karstiques se déplacent au fil du temps, et avec parfois une spectaculaire rapidité. Par exemple, la perte du champ de maïs, au bord de la route N 678 (de Sprimont à Chanxhe) a été localisée en 1995 à 300 m en amont de sa localisation en 1971 ; en 1971, elle était déjà à 350 m en amont de sa situation en 1898. Et en 1999, un autre déplacement de la même perte avait provoqué un effondrement de la route N 678. 4. Conclusions Les phénomènes karstiques du synclinal de Sprimont présentent une dynamique fort active et, dans certains cas, dangereuse pour les travaux des hommes. Les déplacements des points d'enfouissement peuvent poser des problèmes de stabilité des bâtiments et des routes, canalisations, etc., mais aussi des problèmes de pollution. C'est pourquoi il est important de suivre attentivement l'évolution de l'hydrologie karstique. Ceci explique les décisions du Service public de Wallonie de mettre périodiquement à jour la cartographie des phénomènes, et de réglementer les implantations de constructions dans les zones karstiques. [less ▲]

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See detailL'atmosphère de la grotte de Ramioul
Godissart, Jean; Ek, Camille ULg

in Bulletin de la Société Royale Belge d'Etudes Géologiques et Archéologiques "Les Chercheurs de Wallonie" (2010), hors-série n°3

Depuis 2004, un puits de 30 m de la grotte de Ramioul dégage du dioxyde de cargone à des concentrations atteignant 8%. Les concentrations de CO2, O2 et CO ont été enregistrées depuis 2008. Les ... [more ▼]

Depuis 2004, un puits de 30 m de la grotte de Ramioul dégage du dioxyde de cargone à des concentrations atteignant 8%. Les concentrations de CO2, O2 et CO ont été enregistrées depuis 2008. Les histogrammes de CO2 montrent des maximums hivernaux, des minimums en été, et une production 12 à 20 fois plus grande que les autres grottes de Belgique. Le CO2 provient probablement de l'oxydation de la pyrite par les eaux d'infiltration. [less ▲]

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See detailProblème des karsts en roches silicatées... lacunes d’observation et paradigme du karst
Willems, Luc ULg; Ek, Camille ULg; Rodet, Joël et al

Conference (2009, December 05)

Depuis le développement de la karstologie, la grande majorité des cavités prospectées l'ont été dans les roches carbonatées ou apparentées, réputées fort solubles. Partant de ce principe, les autres ... [more ▼]

Depuis le développement de la karstologie, la grande majorité des cavités prospectées l'ont été dans les roches carbonatées ou apparentées, réputées fort solubles. Partant de ce principe, les autres lithologies n'ont été à ce jour que partiellement investiguées puisque réputées peu ou pas solubles. Pourtant, depuis plusieurs siècles, des grottes et autres formes apparentées sont mentionnées notamment dans des grès, des granites ou les quartzites. Très rapidement, elles ont été catégorisées comme pseudokarst en se basant sur deux principes, le premier, la convergence de forme, le second, les processus physico-chimiques qui présideraient à leur formation seraient différents de ceux rencontrés dans les calcaires. L'évolution des recherches et des techniques de ces vingt dernières années ouvre de nouvelles perspectives sur une réalité karstique commune qui transcenderait les lithologies tant carbonatées que non carbonatées. Peu à peu, elle oblige les chercheurs à se repositionner quant à la notion de karst. [less ▲]

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See detailExtreme increase of CO2 in belgian caves
Ek, Camille ULg; Godissart, Jean

in ICS 2009 Proceedings (2009, July)

We began making CO2 measurements in Belgian caves in 1966. Analyses were conducted in cave halls, galleries, fissures and shafts, in various seasons and at different levels above the floors of the ... [more ▼]

We began making CO2 measurements in Belgian caves in 1966. Analyses were conducted in cave halls, galleries, fissures and shafts, in various seasons and at different levels above the floors of the conduits, and in the absence or presence of other human beings. Our first results were published in 1968. From that time on, we have carried out studies in Poland, Quebec, China and other countries but we have focused most of our work in Belgium. We have discovered over these forty years of study, a strong increase in the observed values of CO2 in Belgian caves. For example, a few of our observations follow. “Trou Joney” (Comblain-au-Pont, province of Liege) is a small and shallow cave. We measured at the central point of the main gallery, 1870 ppm CO2 in July 1966, and 13800 ppm at the same location in July 2007. At the bottom of the shaft of the “Comblain-au Pont” cave, we measured 600 ppm in July 1966 and found 1500 ppm in July 2008. In “La Merveilleuse” cave (Dinant, province of Namur), we measured 800 ppm at the central point of the Big Hall in August 1990, rising to 1700 ppm in August 2008. In the main gallery of the “Fontaine de Rivire” cave (Hamoir, province of Liege), we found 5000 ppm in August 1972, increasing to 9400 ppm in 2008. We conclude that the CO2 content of the atmospheres of many caves in Belgium at least, is very sharply getting higher. The increase is very variable, but omnipresent. Are our measurements significant? We believe that we have validated our instruments and our methods. The increase is probably not a result of local industrial activities. The CO2 curves of Mauna Loa Observatory (Hawaii) and “Mace Head” (Ireland) both show an increase of atmospheric carbon dioxide during the last half century. However, the upsurge of CO2 observed in the caves is much greater than the increase in those well-known surface measurements. There is a very complex interrelationship between temperature, vegetation and biomass activity, and CO2 in the soil and underground. The increase of any one of these three parameters can induce changes in the two others, and hence in the partial pressure of CO2 in cave air. [less ▲]

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See detailCRUE DU GAZ CARBONIQUE DANS L'AIR DES GROTTES
Godissart, Jean; Ek, Camille ULg

in EcoKarst (2009)

Carbone dioxide in cave air is strongly increasing for at least forty years.

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See detailPROPOS DISPARATES AUTOUR DE LA GÉOGRAPHIE PHYSIQUE
Ek, Camille ULg

in Bulletin de la Société géographique de Liège (2009), 52

Rambling thoughts about physical geography Theories and paradigms succeed each other as time passes by. Some of the paradigms display a strong tendency to degenerate into laws and rules. Applied research ... [more ▼]

Rambling thoughts about physical geography Theories and paradigms succeed each other as time passes by. Some of the paradigms display a strong tendency to degenerate into laws and rules. Applied research requires team work and hierarchy. It should not be the only kind of research. Financial support is essential to support fundamental research, some of which must remain independent. Systemic approach to research, even in physical geography, thrusts the Human to the forefront. Man becomes an agent, as well as a subject to the process. Research should be structured and open to provide us with the most essential elements necessary, to correctly validate the theories and to be useful to mankind. [less ▲]

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See detailLa Grotte et l'Abîme de Comblain-au-Pont
Ek, Camille ULg; Godissart, Jean

Book published by Découverte de Comblain-au-Pont et environs, ASBL (2007)

Summary: Historical review; Geology; Cave genesis; Climate; Fauna; Paleontology

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See detailKarsts des craies et calcarénites de la Montagne Saint-Pierre (Basse Meuse liégeoise)
Willems, Luc ULg; Rodet, Joël; Ek, Camille ULg et al

in Bulletin des Chercheurs de la Wallonie (2007), XLVI

The “Montagne Saint-Pierre” (Sint Pietersberg) is a separate part of the Hesbaye plateau, isolated between the lower valleys of the Geer and the Meuse rivers. It is exploited by a big open-air quarry and ... [more ▼]

The “Montagne Saint-Pierre” (Sint Pietersberg) is a separate part of the Hesbaye plateau, isolated between the lower valleys of the Geer and the Meuse rivers. It is exploited by a big open-air quarry and by numerous underground quarries developing galleries on hundreds of kilometers long. Excavated in Cretaceous chalk and calcarenite, these artificial networks allow an exceptional 3-D observation of karsts inside a very porous and permeable rock, less favourable to a concentrated solution. The most numerous of them are “organ pipes” or “earth pipes”. They are vertical tubular solution pipes that may exceed 60 m in depth. Sponge networks and subhorizontal caves occur, without any visible connection with fracturation. Finally, downwards to at least 20 m below the alluvial plain of the Meuse river, pluridecametric nodes of weathered chalk are found. By their size and rounded morphology, the nodes resemble to the natural caves occurring in the calcarenite and intersected by the underground quarries. All the studied karsts allow us to propose a scenario for the genesis of a polyphase karst system. Independently of surface conditions, caves are generated deeply in the phreatic zone (endokarsts). During the downcutting of theMeuse valley, and related to the fluvial terraces, solution pipes (input karsts) are generated. Due to the valley incision and to the lowering of the aquifer,theses solution pipes progress downward and cut the endokarsts. A concentrated water circulation takes place. In the dewatered upper part of the system, caves cut by solution pipes are rapidly filled by superficial deposits. The high porosity of the calcarenite makes it comparable to a sponge. The rock absorbs quickly the out-flows coming from the surface and causes a rapid deposit of the fine particles transported inside horizontal passages. The sealing of these conduits allows their conservation inside a very crumbly rock. [less ▲]

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See detailContribution à l'étude du climat de trois cavités souterraines belges
Piron, Julie; Erpicum, Michel ULg; Ek, Camille ULg et al

in Bulletin de la Société Royale Belge d'Etudes Géologiques et Archéologiques (2007), XLVI

Some temperature and CO2 measures have been made for one year in the cave of Ramioul and in the cave of Comblain-au-Pont, and for six months in the underground quarry of Petit-Lanaye inférieure ... [more ▼]

Some temperature and CO2 measures have been made for one year in the cave of Ramioul and in the cave of Comblain-au-Pont, and for six months in the underground quarry of Petit-Lanaye inférieure. Temperature has been measured by dataloggers. These measures and the comparison between the different caves contributed to a better understanding of their climates. In the cave of Ramioul, closed by non insulated doors, the air movements are relatively low but there are some heat exchanges between the outside and inside air by conduction through the doors. The cave can be divided into two parts each with a different climatic behaviour. High and dangerous CO2 rates have already been measured in this cave. Rates fluctuate in an irregular way and without any connection with the natural seasonal cycle, and the CO2 origins stay uncertain. The cave of Comblain-au-Pont can be divided into two major parts: one enclosed and the other ventilated. The ventilated region is a “wind tube” during the winter, but it doesn’t reverse in the summer. On a larger scale, this region can be considered as a cold air trap despite its two exits, since it has a descendant morphology. <br />In the underground carry of Petit-Lanaye inférieure, the low number of data doesn’t allow a complete diagnosis of the climate organisation, but can give a first idea for the summer period. We can already distinguish some parts that are more or less influenced by the outside temperature fluctuations, probably in relation with some air movements which organised <br />themselves in a complex way in the labyrinthic galleries network. [less ▲]

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See detailPolyphase karst system in Cretaceous chalk and calcarenite of the Belgian-Dutch border
Willems, Luc ULg; Rodet, Joël; Fournier, Matthieu et al

in Zeitschrift für Geomorphologie (2007), 51(3), 361-376

Along the Belgian-Dutch border, underground and surface quarries dug in Cretaceous calcarenite and chalk intersect many karst features as well as deep large nodes of weathered rock. Their observation ... [more ▼]

Along the Belgian-Dutch border, underground and surface quarries dug in Cretaceous calcarenite and chalk intersect many karst features as well as deep large nodes of weathered rock. Their observation allows the reconstruction of the genesis of an original karst system resulting from the merging of initially independent endokarsts and exokarsts. Deep weathering has developed within the Cretaceous formations, creating nodes of weathered chalk and closed cavities. These phenomena are expanded over time and can form interconnected voids. Near the surface, solution pipes are generated under the coarsest deposits of a fluvial terrace capping the Cretaceous formations. These pipes develop vertically and may be related to the progressive lowering of the water table in connection with the incision of the Meuse valley. Some of these phenomena cut up the older endokarsts and organize complex systems of out-flow within the chalk. [less ▲]

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See detailKarsts des craies et calcarénites de la Montagne Saint-Pierre (Basse Meuse liégeoise)
Willems, Luc; Rodet, Joël; Ek, Camille ULg et al

in Bulletin de la Société Royale Belge d'Etudes Géologiques et Archéologiques (2007), XLVI

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See detailLe karst
Ek, Camille ULg; Schyns, Jean-Christophe; Ozer, André ULg

in Direction générale de l'aménagement du territoire, du logement et du patrimoine (Ed.) Les risques majeurs en Région wallonne (2006)

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See detailLe monde souterrain : la genèse des cavernes
Ek, Camille ULg

in Bulletin de la Société Royale des Sciences de Liège (2006), 75

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See detailLes phénomènes karstiques de Wallonie
Ek, Camille ULg

in Acte du colloque - Karst et aménagement du Territoire. (2005)

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See detailBalade géologique le long de l'Ourthe, de Liège à Comblain-au-Pont
Ek, Camille ULg; Barchy, Laurent ULg; Marion, Jean-Marc ULg et al

Article for general public (2004)

The regional governement of Wallonia (Région wallonne, DGARNE) is actually supporting (since 1990) the "New geological map of Wallonia" research program, updating the former edition accomplished between ... [more ▼]

The regional governement of Wallonia (Région wallonne, DGARNE) is actually supporting (since 1990) the "New geological map of Wallonia" research program, updating the former edition accomplished between 1890 and 1919. The Walloon Region wants to enrich it by explicative works aiming to reach a large public like families, young people, etc... and to link physical activities to natural discoveries, in the respect of environment and nature. [less ▲]

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See detailKarst in granitic rocks, South Cameroon: cave genesis and silica and taranakite speleothems
Willems, Luc ULg; Compère, Philippe ULg; Hatert, Frédéric ULg et al

in Terra Nova (2002), 14(5), 355-362

A cave in granitic rocks was studied in Mezesse, South Cameroon. Coralloid speleothems, draperies and dissolution traces on the cave walls attest to its truly karstic nature. The speleothems consist of ... [more ▼]

A cave in granitic rocks was studied in Mezesse, South Cameroon. Coralloid speleothems, draperies and dissolution traces on the cave walls attest to its truly karstic nature. The speleothems consist of microlayers of opal and taranakite (K,NH4)Al-3(PO4)(3)(OH).9H(2)O. They indicate a significant mobilization of silica, Al and K from granite during the formation of the cave. Identification of silicified bacteria in the speleothems layers suggests a possible role of these micro-organisms in silica deposition. The presence of taranakite and of silicified organic remains within the speleothems lead to a better understanding of the genesis of the cave. [less ▲]

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