References of "Ek, Camille"
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See detailL’air des grottes de Belgique s’enrichit en CO2 au fil des années
Ek, Camille ULiege; Godissart, Jean

in Science et Culture (2019), 477

Cave air CO2 rises much faster than open air

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See detailCharacterizing the Eemian-Weichselian transition in northwestern Europe with three multiproxy speleothem archives from the Belgian Han-sur-Lesse and Remouchamps cave systems
Vansteenberge, Stef; Verheyden, Sophie; Genty, Dominique et al

in Quaternary Science Reviews (2019)

Interglacial to glacial transitions represent the most drastic turnovers in the Quaternary climate system. Yet, millennial-scaled climate variability and stochastic internal variability that result in ... [more ▼]

Interglacial to glacial transitions represent the most drastic turnovers in the Quaternary climate system. Yet, millennial-scaled climate variability and stochastic internal variability that result in these transitions remain still poorly understood. Here, three speleothem archives from two different cave systems in Belgium (Han-sur-Lesse and Remouchamps) are investigated using a multiproxy approach in order to characterize the last interglacial to glacial transition. The studied samples roughly span the period between 125 ka and 100 ka, covering a large part of the Eemian and early Weichselian. The speleothems show a high reproducibility for δ13C, which is interpreted as a proxy for past vegetation activity, controlled by vegetation assembly above the cave. All three speleothems show a drastic increase in δ13C between 118 to 117 ka, reflecting a rapid change of vegetation assembly from last interglacial temperate tree species towards glacial more open grass vegetation. This event shows a strong affinity in terms of timing and climatic expression with the Late Eemian Aridity Pulse (LEAP) at 118 ± 1 ka, identified in pollen records from Western Germany. Aligning the chronologies of the two independently dated Han-sur-Lesse speleothem records enables a more precise absolute chronology and provides an age of 117.7 ± 0.5 ka to the start of this event in the Belgian speleothems. This event marks a distinct transition in the Belgian speleothem proxies between Eemian optimum conditions and increased variability during the glacial inception and the start of this event at 117.7 ± 0.5 ka is therefore proposed as the Eemian- Weichselian transition and consequently the start of the glacial inception in the studied speleothems. High-resolution analysis shows that the 117.7 ± 0.5 ka event is initiated by a cooling pulse followed by a decrease in precipitation. A similar short-lived cooling event is also registered in multiple North-Atlantic sediment archives. This study hypothesizes that the origin of the cooling event at 117.7 ka is an internal climate response caused by the substantial amount of freshwater input from degraded ice-sheets by the end of the Eemian (~120-118 ka). There is thus a clear climatic connection between the Belgian speleothems and other continental European archives and North Atlantic marine archives, providing the possibility of improving less constrained chronologies by alignment to the independently constructed speleothem age-depth model presented in this study. [less ▲]

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See detailLE MUR GÉOLOGIQUE DE COMBLAIN Echelle stratigraphique de 540 millions d’années en cours de construction !
Michel, Georges; Remacle, Laurence ULiege; Ek, Camille ULiege

in Eco Karst (2018), 112

A Comblain-au-Pont, à côté de la Carrière du Petit Banc, une curieuse “rampe de pierre” est en construction. Devant à terme atteindre 54m, elle représentera l’ensemble des formations géologiques de la ... [more ▼]

A Comblain-au-Pont, à côté de la Carrière du Petit Banc, une curieuse “rampe de pierre” est en construction. Devant à terme atteindre 54m, elle représentera l’ensemble des formations géologiques de la Belgique, de l’ère Primaire jusqu’à aujourd’hui. [less ▲]

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See detailPoint Dilution Tracer Test to Assess Slow Groundwater Flow in an Auxiliary Karst System (Lake of Fontaine de Rivîre, Belgium)
Meus, Philippe; Flament, Jérémy; Willems, Luc ULiege et al

in Eurokarst 2018 Proccedings (2018)

The quantification of mass transfer through auxiliary karst systems is addressed by using a specific point dilution long-term tracer test. The physical functioning of such systems is usually only inferred ... [more ▼]

The quantification of mass transfer through auxiliary karst systems is addressed by using a specific point dilution long-term tracer test. The physical functioning of such systems is usually only inferred by hydrodynamical and environmental tracer data, whose interpretation often relies on invalidated assumptions. The new approach is a way for experimentally validating or complementing the classical approaches. The lake of Fontaine de Rivîre is an auxiliary karst system in the Frasnian limestones of the Ourthe Valley in Belgium. Its particular confinement was studied by conjunctional use of natural responses and single-point dilution tracer test, with an injection of 41 g of uranine on 22 March 2017. The tracer test was monitored during one year using fluorometers, water and charcoal samplings at five points in the lake and six points at the surface (no connection having been established outside). [less ▲]

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See detailL'échelle géologique de Comblain-au-Pont : un monument à la pierre.
Ek, Camille ULiege

in Achéo-contact. Cercle archéo-historique Le vieil Esneux (2018), 53

A stratigraphic scale of Belgium, made of true stones, is under construction at Comblain-au-Pont (Belgium).In December 2018, the scale had reached the Devonian Period.

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See detailKarstic Systems in Eastern Belgium: Remouchamps and Noû Bleû
Peeters, Alexandre ULiege; Ek, Camille ULiege

in Demoulin, Alain (Ed.) Landscapes and Landforms of Belgium and Luxembourg (2018)

Belgium is characterised by a wide variety of rocks, including carbonate formations, which are significantly represented in eastern Belgium. Among those formations, Devonian and Carboniferous carbonates ... [more ▼]

Belgium is characterised by a wide variety of rocks, including carbonate formations, which are significantly represented in eastern Belgium. Among those formations, Devonian and Carboniferous carbonates display the most developed karstic features, as illustrated by the two cave systems presented in this chapter. Although both systems are water caves, they differ in many ways. The Remouchamps Cave, developed in the Upper Devonian limestones, is a touristic cave, while the Noû Bleû Cave, developed in the Carboniferous carbonates, is a brand new discovery still under exploration. The two systems are of scientific interest and contain many deposits (speleothems and detrital sediments) providing records of past environmental changes and paleoclimates. Beside the Quaternary dynamics, the present-day dynamics can be highlighted within the karstic basins that encompass the two cave systems. The generation or reactivation of sinkholes and swallow holes is often favoured or triggered by human activity. Furthermore, the two basins offer several good examples of human interaction with karst environments, not only in terms of karstic constraints for humans but also as a resource that must be preserved. [less ▲]

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See detailA case study of anthropogenic impact on the CO2 levels in low-volume profile of the Balcarka Cave (Moravian Karst, Czech Republic)
Lang, Marek; Faimon, Jiri; Ek, Camille ULiege

in Acta Carsologica (2015), 44(1), 71-80

Anthropogenic impact on CO2 levels was studied in the low-volume chamber connected with the low-profile corridor in Balcarka Cave, the show cave in Moravian Karst, during the period of limited ventilation ... [more ▼]

Anthropogenic impact on CO2 levels was studied in the low-volume chamber connected with the low-profile corridor in Balcarka Cave, the show cave in Moravian Karst, during the period of limited ventilation. Modeling showed that the natural CO2 levels were controlled by the CO2 fluxes (up to ~ 3.14 × 10-2 mol s-1) from adjacent spaces. These fluxes changed with cave airflows and ventilation modes. Two main components of anthropogenic impact were recognized: (1) visitor breathing and (2) visitor movement. The CO2 input derived from individual visitor groups varied from 1.96 × 10-4 to 2.45 × 10-3 mol s-1, which was the significant part of the CO2 fluxes from adjacent spaces. The visitor movement induced the airflows up to 0.2 m3 s-1. They exceeded the natural airflows (up to 3.2 × 10-3 m3 s-1) by factor of more than 60. These airflows caused cave ventilation mode’s switching and, significant drop of CO2 fluxes/levels due to changed ventilation. The study therefore indicates that various anthropogenic influences in show cave can balance and neutralize each other, in dependence on cave morphology and seasonal conditions. [less ▲]

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See detailThe relationship between carbon dioxide concentration and visitor numbers in the homothermic zone of the Balcarka Cave (Moravian Karst) during a period of limited ventilation
Lang, Marek; Faimon, Jiri; Ek, Camille ULiege

in International Journal of Speleology (2015), 44(2), 167-176

The evolution of CO2 levels with and without human presence was studied in a selected site (Gallery Chamber) of the homothermic zone of the Balcarka Cave (Moravian Karst, Czech Republic) during the fall ... [more ▼]

The evolution of CO2 levels with and without human presence was studied in a selected site (Gallery Chamber) of the homothermic zone of the Balcarka Cave (Moravian Karst, Czech Republic) during the fall, a period of limited ventilation. There were recognized various factors controlling the cave CO2 levels under different conditions in the exterior and interior. When visitors were absent, CO2 levels were controlled by the advective CO2 fluxes linked to cave airflows and reaching up to ~1.5 x 10-3 mol s-1. These fluxes exceed by orders of magnitude the exchanged diffusive fluxes (up to 4.8 x 10-8 mol s-1) and also the natural net flux (from 1.7 x 10-6 to 6.7 x 10-6 mol s-1) imputing given chamber directly from overburden. The natural net flux, normalized to unitary surface area, was estimated to be 2.8 x 10-8 to 1.1 x 10-7 mol m-2 s-1, based on a perpendicular projection area of the chamber of ~60 m2. When visitors were present, the anthropogenic CO2 flux into the chamber reached up to 3.5 x 10-3 mol s-1, which slightly exceeded the advective fluxes. This flux, recalculated per one person, yields the value of 6.7 x 10-5 mol s-1. The calculations of reachable steady states indicate that anthropogenic fluxes could almost triple the natural CO2 levels if visitors stayed sufficiently long in the cave. [less ▲]

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See detailCarbon dioxide in cave air and soil air in some karstic areas of Belgium
Ek, Camille ULiege; Godissart, Jean

in Geologica Belgica (2014)

ABSTRACT. Caves are privileged observatories of underground air and its carbon dioxide content. The carbon dioxide partial pressure in Belgian caves displays seasonal fluctuations with strong summer ... [more ▼]

ABSTRACT. Caves are privileged observatories of underground air and its carbon dioxide content. The carbon dioxide partial pressure in Belgian caves displays seasonal fluctuations with strong summer maxima. Besides, CO2 concentration has risen very significantly in Belgian caves since our first measurements in the nineteen sixties. To understand the cause of this rise, we have been measuring the air in the soil above the Comblain-au-Pont cave since 2008, with a device developed by Jean Godissart. These measurements show clear seasonal variations, the maximum occurring in early summer, well before the maximum in the caves. This confirms the influence of vegetation as a source of carbon dioxide in the caves. It is well known that atmospheric CO2 concentration and temperature are two factors influencing the growth of vegetation. And the stock of vegetation is indeed increasing in Belgium, where the volume of wood in tree trunks in the Walloon Region forests rose about 30% in the thirty years from 1984 to 2005. The increase in vegetation is of course correlative with the soil biological activity. We firmly believe that this explains a large part of the CO2 rise in cave air. [less ▲]

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

in International Congress of Speleology Proceedings (2013)

Carbon dioxide (thought to come in the main from plant root and biomass respiration) displays seasonal variations related to outside temperature, but some oscillations of the CO content of cave air are ... [more ▼]

Carbon dioxide (thought to come in the main from plant root and biomass respiration) displays seasonal variations related to outside temperature, but some oscillations of the CO content of cave air are related to surface barometric variations (i.e., when the barometric pressure falls, a certain amount of air trapped in the remote parts of the system leaks outside and vice versa). A sudden drop of temperature, inducing a chimney effect may cause a drop of the air-CO2 content of a deep pit from 4000 to 1300 ppm. [less ▲]

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See detailLa dynamique du karst dans le synclinal de Sprimont de 1898 à 2012
Peeters, Alexandre ULiege; Ek, Camille ULiege; 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 ULiege; Ek, Camille ULiege; 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 detailGeotourism in the Ourthe valley, Province of Liège, Belgium
Ek, Camille ULiege

in Contact forum. Geoheritage, geoconservation & geotourism (2012)

The Ourthe valley is particularly favourable for projects of geotourism. Between Comblain-au-Pont and Liège, where the river flows into the Meuse River, a lot of outcrops are visible, and at some places ... [more ▼]

The Ourthe valley is particularly favourable for projects of geotourism. Between Comblain-au-Pont and Liège, where the river flows into the Meuse River, a lot of outcrops are visible, and at some places spectacular. At Comblain-au-Pont, a tourist cave, several wild caves, an underground quarry and a geological trail make the village a geological paradise. [less ▲]

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See detailLe système karstique de la Lomme. Quelques points d'observation remarquable
Willems, Luc ULiege; Ek, Camille ULiege

in Professional Paper (2011), 2011/2(309), 11-26

Présentation de quelques sites karstiques remarquables situés sur la commune de Rochefort

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See detailLe système karstique de la Lomme, région de Rochefort, cadre général
Willems, Luc ULiege; Ek, Camille ULiege; Marion, Jean-Marc ULiege

in Professional Paper (2011), 2011/2(309), 3-10

“La Calestienne” is the strip of Devonian limestones which separates the Ardennes from the Famenne and Condroz regions. It contains the most important karstic phenomena in Belgium. The karst system ... [more ▼]

“La Calestienne” is the strip of Devonian limestones which separates the Ardennes from the Famenne and Condroz regions. It contains the most important karstic phenomena in Belgium. The karst system developed over 10 kilometers along the river Lomme (Lhomme) and its main tributary, the Wamme, in the region of Rochefort, illustrates the main characteristics of the Calestienne. The Calestienne around Rochefort is bordered to the northwest by the wide depression of the Famenne shales, the altitude of which oscillates between 150 and 200 meters. In the southeast of this limestone strip, the Ardenne, a region composed of more resistant rocks, rises to altitudes often greater than 400 m. In the landscape, the Calestienne forms a real step at an intermediate altitude. To the Northeast of Rochefort, the limestone strip widens out considerably due to the Gerny anticline. [less ▲]

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

in Bulletin de la Société Royale Belge d'Études Géologiques et Archéologiques (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 ULiege; Ek, Camille ULiege; 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 ULiege; 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 ULiege

in EcoKarst (2009)

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

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